U.S. patent application number 12/498325 was filed with the patent office on 2010-01-07 for polymer having polymerizable group, polymerizable composition, planographic printing plate precursor, and planographic printing method using the same.
Invention is credited to Kazuto KUNITA, Sumiaki Yamasaki.
Application Number | 20100003618 12/498325 |
Document ID | / |
Family ID | 35517371 |
Filed Date | 2010-01-07 |
United States Patent
Application |
20100003618 |
Kind Code |
A1 |
KUNITA; Kazuto ; et
al. |
January 7, 2010 |
POLYMER HAVING POLYMERIZABLE GROUP, POLYMERIZABLE COMPOSITION,
PLANOGRAPHIC PRINTING PLATE PRECURSOR, AND PLANOGRAPHIC PRINTING
METHOD USING THE SAME
Abstract
A polymer having a polymerizable group and an alkyleneoxy groups
on side chains thereof, and a polymerizable composition containing
the polymer. The polymerizable composition preferably contains a
polymerizable compound and a polymerization initiator. Also
provided is a planographic printing plate precursor having a
polymerizable layer on a hydrophilic support, the polymerizable
layer containing a polymer having a polymerizable on a side chain
thereof. The planographic printing plate precursor can form an
image without being subjected to an alkali development. An
undercoat layer containing a specific copolymer may be provided
between the support and the photopolymerizable layer.
Inventors: |
KUNITA; Kazuto;
(Shizuoka-ken, JP) ; Yamasaki; Sumiaki;
(Shizuoka-ken, JP) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Family ID: |
35517371 |
Appl. No.: |
12/498325 |
Filed: |
July 6, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12073796 |
Mar 10, 2008 |
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12498325 |
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11182830 |
Jul 18, 2005 |
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12073796 |
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Current U.S.
Class: |
430/287.1 |
Current CPC
Class: |
C08F 8/14 20130101; G03F
7/3035 20130101; C08F 8/14 20130101; C08F 212/34 20130101; C08F
2/50 20130101; G03F 7/0388 20130101; B41C 2210/20 20130101; C08F
12/26 20130101; C08F 8/26 20130101; C08F 220/40 20130101; C08F
220/18 20130101; B41C 2201/10 20130101; B41C 1/1016 20130101; B41M
5/368 20130101; C08F 222/104 20200201; C08F 220/40 20130101; C08F
220/40 20130101; C08F 222/102 20200201; B41C 2210/04 20130101; B41C
2201/14 20130101; C08F 4/00 20130101; C08F 220/54 20130101; C08F
12/22 20130101; C08F 8/14 20130101; C08F 8/14 20130101; C08F 220/14
20130101; C08F 220/40 20130101; C08F 220/28 20130101; C08F 220/54
20130101; C08F 220/14 20130101; C08F 220/56 20130101; C08F 220/14
20130101; C08F 220/54 20130101; C08F 226/06 20130101; C08F 220/14
20130101; C08F 220/382 20200201; C08F 220/14 20130101; C08F 220/54
20130101; C08F 220/18 20130101; C08F 220/14 20130101; C08F 226/10
20130101; C08F 220/382 20200201; C08F 220/14 20130101; C08F 220/40
20130101; B41C 1/1008 20130101; C08F 12/30 20130101; B41C 2201/04
20130101; C08F 220/20 20130101; C08F 8/26 20130101; C08F 222/1006
20130101; C08F 220/54 20130101; B41C 2201/02 20130101; B41C 2210/06
20130101; C08F 222/00 20130101; B41C 2210/24 20130101; C08F 212/14
20130101; B41C 2201/06 20130101; B41C 2210/22 20130101; C08F 220/22
20130101; Y10S 430/145 20130101; C08F 220/06 20130101 |
Class at
Publication: |
430/287.1 |
International
Class: |
G03F 7/004 20060101
G03F007/004 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 10, 2004 |
JP |
2004-264486 |
Sep 14, 2004 |
JP |
2004-266489 |
Jun 13, 2005 |
JP |
2005-172871 |
Claims
1-19. (canceled)
20. A planographic printing plate precursor comprising a support
and a laser-sensitive recording layer, wherein the planographic
printing plate can be used for printing after exposure without
being developed with an alkaline developer, the recording layer
includes a polymer having a polymerizable group on a side chain
thereof, and wherein: the planographic printing plate precursor is
developable by i) attaching the planographic printing plate
precursor to a printing machine; ii) imagewise exposing the
planographic printing plate precursor to laser light; and iii)
supplying printing ink and moistening water to the planographic
printing plate precursor so as to remove the recording layer in
unexposed regions and so as to generate a printing plate and
conduct printing, the polymer has a group represented by formula
(1), (2), or (3) on a side chain thereof: ##STR00183## wherein in
formulae (1) to (3), X represents an oxygen atom, a sulfur atom, or
--N--R.sup.12; Y represents an oxygen atom, a sulfur atom, or
--N--R.sup.12; Z represents an oxygen atom, a sulfur atom,
--N--R.sup.12, or a phenylene group; and R.sup.1 to R.sup.12 each
independently represent a monovalent substituent, the polymer does
not have an alkali-soluble group, and the planographic printing
plate precursor further comprises an undercoat layer provided
between the support and the recording layer, and the undercoat
layer includes a copolymer comprising a first repeating unit having
an ethylenic unsaturated bond and a second repeating unit having a
functional group capable of interacting with a surface of the
support.
21. The planographic printing plate precursor according to claim
20, wherein the copolymer in the undercoat layer comprises a
repeating unit represented by the following formula (I)
##STR00184## wherein in formula (I), x and y represent
copolymerization ratios, A.sub.1 represents a repeating unit having
an ethylenic unsaturated bond and A.sub.2 represents a repeating
unit represented by the following formula (A2) ##STR00185## wherein
in formula (A2), R.sub.1 to R.sub.3 each independently represent a
hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a
halogen atom, L represents a divalent connecting group selected
from the group consisting of --CO--, --O--, --NH--, a divalent
aliphatic group, a divalent aromatic group, and a combination
thereof and Q represents the following group: ##STR00186## wherein
M.sub.1 and M.sub.2 each independently represent a hydrogen atom, a
metal atom or an ammonium group, and when the repeating unit
represented by (A2) does not contain a hydrophilic portion, the
copolymer may further include a repeating unit represented by the
following formula (A3) ##STR00187## wherein in formula (A3),
R.sub.1 to R.sub.3 each independently represent a hydrogen atom, an
alkyl group having 1 to 6 carbon atoms, or a halogen atom, L
represents a divalent connecting group selected from the group
consisting of --CO--, --O--, --NH--, a divalent aliphatic group, a
divalent aromatic group, and a combination thereof and W represents
the following group: ##STR00188## wherein M.sub.1 represents a
hydrogen atom, a metal atom or an ammonium group.
22. The planographic printing plate precursor according to claim
20, wherein the recording layer includes a copolymer comprising a
first repeating unit having an ethylenic unsaturated bond and a
second repeating unit having a functional group capable of
interacting with a surface of the support.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional application of co-pending
application Ser. No. 12/073,769, filed on Mar. 10, 2008, which is a
divisional application of application Ser. No. 11/182,830, filed on
Jul. 18, 2005, the entire contents of which are hereby incorporated
by reference and for which priority is claimed under 35 U.S.C.
.sctn.120.
[0002] This application claims priority under 35 USC .sctn.119 to
Japanese patent Application Nos. 2004-264486, 2004-266489, and
2005-172871, the disclosure of which is hereby incorporated by
reference.
BACKGROUND OF THE INVENTION
[0003] 1. Field of the invention
[0004] The invention is concerned with a polymerizable composition
which can be polymerized and cured by light or heat, a planographic
printing plate precursor using the same, and a planographic
printing method using the same. Specifically, the invention relates
to a stable polymerizable composition capable of polymerizing with
high sensitivity which is useful for use in a recording layer of a
planographic printing plate precursor which can be used for
printing without being alkali-developed after exposure to laser
light. The invention also relates to a planographic printing plate
precursor and a planographic printing method using the printing
plate precursor, the method comprising on-press development but not
comprising usual development operation.
[0005] 2. Description of the related art
[0006] Generally, a planographic printing plate comprises
lipophilic image portions receiving ink at printing and hydrophilic
non-image portions receiving moistening water. The planographic
printing comprises: forming ink-receiving portions which are
lipophilic image portions and moistening water receiving portions
(ink-repelling portions) which are hydrophilic non-image portions
on a planographic printing plate so as to make irregularity of ink
adhesiveness on the surface of the planographic printing plate;
allowing ink to adhere only to the image portions utilizing the
repulsion between water and oil-based ink; and transferring the ink
to a member (such as paper) on which the image is to be printed to
conduct printing.
[0007] Planographic printing plate precursors (PS plates) have been
widely used for making planographic printing plates, which printing
plate precursors have a hydrophilic support and a lipophilic
photosensitive resin layer (image-recording layer) on the support.
Usually, the planographic printing plate precursor is exposed to
light which has passed an element having an image such as a lith
film, and then the image-recording layer in non-image portions is
removed by being dissolved in an alkaline developer or an organic
solvent while allowing the image-recording layer in image portions
to remain so that the surface of the hydrophilic support is
partially exposed in accordance with the image to form a
planographic printing plate.
[0008] Conventionally, recording materials each having a resin
layer which can be polymerized and cured by light or heat have been
widely used as recording materials for planographic printing plate
precursors.
[0009] Digitalization techniques have been spreading widely which
process, store, and output image information electronically by
using computers. In accordance with the development of
digitalization techniques, new image out-put methods have been put
into practice which are adapted to such digitalization techniques.
As a result, there is a demand for computer-to-plate (CTP)
techniques which comprise scanning a printing plate precursor with
a light with high directivity such as a laser light according to
digitalized image information, thereby directly producing a
printing plate without using a lith film. Accordingly, it has been
an important issue to develop an image-recording material adapted
for such techniques.
[0010] An image-recording material proposed as a scan-exposable
recording material has a constitution in which a hydrophilic
support has thereon a lipophilic photosensitive resin layer
(hereinafter occasionally referred to as "photosensitive layer")
including a photosensitive compound capable of generating active
species such as radicals and Bronsted acids upon exposure to laser
light. This image-recording material is commercially available as a
planographic printing plate precursor. A negative planographic
printing plate can be obtained by: scanning the planographic
printing plate precursor with a laser light according to digital
information to generate active species which causes chemical or
physical changes of the photosensitive layer, thereby
insolubilizing the photosensitive layer; and then developing the
planographic printing plate precursor.
[0011] Specifically, a planographic printing plate with high
resolution and high ink-affinity can be obtained efficiently by a
simple developing treatment when the planographic printing plate
precursor has a hydrophilic support and a photopolymerizable
photosensitive layer (recording layer) containing a
photopolymerization initiator excellent in response speed, an
addition-polymerizable ethylenic unsaturated compound, and a binder
polymer which is soluble in an alkaline developer, and an optional
oxygen-blocking protective layer on the support. A planographic
printing plate having the desired characteristics can be produced
from such a planographic printing plate precursor.
[0012] A highly-sensitive radical-polymerizable recording material
suitable for use as a recording layer of a planographic printing
plate usually comprises a combination of an alkali-soluble polymer
binder and a polymerizable crosslinking agent (monomer or
oligomer). In order to improve sensitivity of a polymerizable
composition containing the combination, techniques have been
proposed; a technique disclosed in Japanese Patent Application
Laid-Open (JP-A) No. 2000-187322 provides a radical polymerizable
group to the binder, and a technique disclosed in JP-A No.
2001-290271 introduces a phenyl group substituted by a vinyl group
to a side chain of the binder. When the binder polymer has a
radical polymerizable group, the binder, which is a
high-molecular-weight compound, can directly participate in
cross-linking, thus enhancing the cross-linking effects by
molecular-weight effects and improving the sensitivity. However,
the introduction of the polymerizable group makes thermally
instable the polymer and the polymerizable composition containing
the polymer. The image quality is deteriorated when such techniques
are applied; particularly, the polymerizable composition may
deteriorate because of the high gelling efficiency of the
cross-linking binder when stored in a condition of high temperature
and high humidity, and decrease in developability of a non-image
portion may cause poor reproducibility of thin lines if the
non-image portion is a space between the thin lines. Therefore,
there has been a need for a composition which cures with high
sensitivity to form a tough film only in exposed portions while
maintaining high removability of non-exposed portions.
[0013] In conventional techniques, a process for making a
planographic printing plate has to have a process for removing
non-image portions after exposure; the non-image portions are
removed by being dissolved in a developer suitable for the
image-recording layer. It has been an issue to eliminate the need
for the additional wet process described above or simplify the wet
process. Particularly, the industry has paid attention to the
disposal of the waste liquid occurring in the wet process, in
consideration of the global environment; accordingly, there is a
stronger request for solving the above problems.
[0014] As a simple method for making a printing plate which can
solve the problems, an on-press development method has been
proposed in which the recording layer is such a recording layer
that non-image portions of the planographic printing plate
precursor can be removed in a usual printing procedure, and in
which the non-image portions is removed on the printing machine to
form a planographic printing plate.
[0015] Specifically, the on-press development may be carried out in
the following manners: a method using a planographic printing plate
precursor having such an image-recording layer as to be dissolved
or dispersed in an emulsion containing the moistening water and the
solvent of the ink or in an emulsion containing the moistening
water and the ink; a method comprising physically removing the
image-recording layer by the contact between the image-recording
layer and the rollers or blanket cylinder; and a method comprising
weakening the cohesive force of the image-recording layer or the
adhesion force working between the image-recording layer and the
support by penetration of the moistening water and the ink solvent
into the image-recording layer, and physically removing the
image-recording layer by the contact between the image-recording
layer and the rollers or blanket cylinder.
[0016] In the invention, the term "developing treatment" refers to
a treatment in which: a planographic printing plate precursor which
was exposed to infrared laser light or the like is brought into
contact with a liquid (usually an alkaline developer) using an
apparatus (usually, an automatic processor) which is not a printing
machine such that non-exposed portions are removed to expose the
surface of the hydrophilic support. In the invention, the term
"on-press development" refers to a method or treatment in which a
planographic printing plate precursor is brought into contact with
a liquid (usually a non-alkaline aqueous solution such as printing
ink and moistening water) using a printing machine such that
non-exposed portions of the planographic printing plate precursor
is removed to expose the surface of the hydrophilic support.
[0017] A planographic printing plate precursor disclosed in
Japanese Patent 2938397 etc. is an image-recording material capable
of on-press development which has, on a hydrophilic support, an
image-recording layer containing hydrophobic thermoplastic polymer
particles dispersed in a hydrophilic binder. The planographic
printing plate precursor can be developed on-press with moistening
water and/or ink and exhibits excellent on-press developability;
the planographic printing plate precursor is exposed to a laser
light to fuse the thermoplastic polymer particles to form an image
and then attached to the cylinder of a printing machine, and then
developed on-press. However, when the image is formed by mere
thermal fusion of the particles, the strength of the obtained image
is poor and printing durability is insufficient; particularly, the
adhesion between the support and the ink-receiving layer is very
weak.
[0018] A planographic printing plate precursor having, on a
hydrophilic support, microcapsules containing a polymerizable
compound has been proposed for example in JP-A Nos. 2001-277740 and
2001-277742.
[0019] Further, a planographic printing plate precursor having, on
a support, a photosensitive layer containing an infrared absorber,
a radical polymerization initiator, and a polymerizable compound
has been proposed for example in JP-A No. 2002-287334.
[0020] Another planographic printing plate precursor capable of
on-press development has been disclosed for example in JP-No.
2002-287334. This planographic printing plate precursor has, on a
support, a photosensitive layer containing an infrared absorber, a
radical polymerization initiator such as an onium salt or an
organic borate compound, and a polymerizable compound having an
ethylenic unsaturated double bond such as acrylic ester.
[0021] The image portion formed by the polymerization has a higher
denseness of chemical bonds in the image portion than the image
portion formed by the thermal fusion of polymer particles.
Therefore, the image portion formed by the polymerization has a
better image strength; however, even such a planographic printing
plate precursor fails to achieve sufficient on-press
developability, printing durability, and polymerization efficiency
(sensitivity) from the practical viewpoint, whereby the
planographic printing plate precursor has not been put into
practice.
[0022] Therefore, there is a need for a polymerizable composition
which has high sensitivity and curability and which enables easy
removal of non-cured portions with a non-alkaline water or the like
without requiring removing treatment with an excessive amount of
developer.
SUMMARY OF THE INVENTION
[0023] After intensive research, the inventors have found that the
above problems can be solved by using a radical-crosslinkable
alkali-soluble polymer having a polymerizable group on a side chain
and having a partial structure with a high
water-dispersability.
[0024] A first aspect of the invention is to provide a
radical-crosslinkable polymer having a polymerizable group and an
alkyleneoxy group on a side chain or side chains thereof. The
polymerizable group may be a styrene group.
[0025] A second aspect of the invention is to provide a
polymerizable composition. The polymerizable composition includes a
radical-crosslinkable polymer (hereinafter occasionally referred to
as "specific polymer (A)") having a styrene group and an
alkyleneoxy group on a side chain or side chains thereof.
[0026] The polymerizable composition may further comprise a
polymerizable compound and a polymerization initiator. From the
viewpoint of sensitivity, the polymerizable composition may further
comprise a sensitizing colorant.
[0027] The mechanism of the present invention is supposed to be as
follows: the polymer binder of the invention has, on a side chain,
a styrene group, which is hydrophobic and which improves the
strength of the cured film; the polymer binder of the invention
further has an alkyleneoxy group, which is hydrophilic and capable
of crosslinking by a chain reaction; the combination of the two
groups provides synergetic effects, thereby imparting superior
characteristics to the polymerizable composition.
[0028] When the polymerizable composition is used, a cured film
with excellent water resistance is formed in exposed portions by
crosslinking between hydrophobic styrene groups; further,
alkyleneoxy groups can cause chain reactions involving radicals
when the hydrogen adjacent to the oxygen is pulled out, thereby
improving the cross-linking denseness and sensitivity. The obtained
film is strong and cannot be removed by moistening water or water
containing a surfactant used in printing.
[0029] In unexposed portions, uncured film is easily removed at
printing by contact with ink, moistening water, a water containing
a surfactant, or the like since the alkyleneoxy group has a high
hydrophilicity and high dispersibility in water. Therefore, a
planographic printing plate precursor having a recording layer
including the polymerizable composition can form an image with
clear distinction between unexposed portions and exposed portions
on a printing machine without being subjected to an
alkali-developing treatment. The planographic printing plate
precursor can form an image with high quality without being
subjected to an alkali-developing treatment, supposedly because of
the mechanism described above.
[0030] The polymerizable composition of the invention may be used
suitably as a recording layer of a planographic printing plate
precursor which is capable of direct plate-making and which is
adapted for an infrared LD laser having a wavelength of 800 nm or
longer or an ultraviolet LD laser having a wavelength in the range
of 300 nm to 450 nm. Exposure with an infrared LD laser uses a
mechanism for image formation in which light is converted to heat
which then generate radicals to proceed polymerization. Although
exposure with an infrared LD laser enables exposure with high
illumination, the curing caused by a radical reaction is
insufficient in the neighborhood of the support because of heat
diffusion. However, such a problem can be solved by using the
polymerizable composition of the invention because: in exposed
portions (image portions), the hydrophobic styrene groups form a
strong cured film to which moistening water or the like is
difficult to penetrate at the time of printing, and the film
formation occurs with high sensitivity owing to the characteristics
of the alkyleneoxy groups, and the alkyleneoxy groups further
increase crosslinking denseness of the film. On the other hand, the
illumination intensity of an ultraviolet LD laser used for
recording is low. The polymerizable composition of the invention is
also suitable for exposure by an ultraviolet LD laser since the
polymerizable composition of the invention has high sensitivity and
curability and can form a dense film.
[0031] A third aspect of the invention is to provide a planographic
printing plate precursor comprising a support and a laser-sensitive
recording layer disposed on the support, wherein the planographic
printing plate precursor can be used for printing after exposure
without being developed with an alkaline developer, and the
recording layer includes a polymer having a polymerizable group on
a side chain thereof. The support may be a hydrophilic support. The
polymerizable group may be a styrene group or a group having an
ethylenic unsaturated bond.
[0032] A fourth aspect of the invention is to provide a
planographic printing plate precursor comprising a support and a
recording layer including a polymerizable composition disposed on
the support, wherein the planographic printing plate precursor is
capable of recording image by laser exposure, the planographic
printing plate can be used for printing after exposure without
being developed with an alkaline developer, and the polymerizable
composition includes a radical-crosslinkable polymer (specific
polymer (A)) having a styrene group and an alkyleneoxy group on a
side chain or side chains thereof.
[0033] A fifth aspect of the invention is to provide a planographic
printing method comprising: attaching a planographic printing plate
precursor to a printing machine; imagewise exposing the
planographic printing plate precursor to laser light; and supplying
printing ink and moistening water to the planographic printing
plate precursor so as to remove a laser-sensitive recording layer
in unexposed regions and so as to conduct printing, wherein the
planographic printing plate precursor comprises a support and the
laser-sensitive recording layer disposed on the support, and the
laser-sensitive recording layer includes a polymer having a
polymerizable group on a side chain thereof.
[0034] A sixth aspect of the invention is to provide a planographic
printing plate precursor. The planographic printing plate precursor
can form an image without being subjected to an alkali-developing
treatment. The planographic printing plate precursor has a
laser-sensitive photopolymerizable layer on a hydrophilic support,
and the photopolymerizable layer includes a polymer compound having
at least one ethylenic unsaturated bond on side chains.
[0035] The polymer compound having at least one ethylenic
unsaturated bond on side chains may be a polymer compound having at
least one group selected from groups represented by the following
formulae (1) to (3).
##STR00001##
[0036] In the formulae, X and Y each independently represent an
oxygen atom, a sulfur atom, or --N--R.sup.12; Z represents an
oxygen atom, a sulfur atom, --N--R.sup.12, or a phenylene group;
and R.sup.1 to R.sup.12 each independently represent a monovalent
substitutent.
[0037] The photopolymerizable layer may include a microcapsule. In
an embodiment, the photopolymerizable layer or another layer
includes a copolymer comprising a repeating unit (a1) including an
ethylenic unsaturated group and a repeating unit (a2) including a
functional group capable of interacting with the surface of the
support.
[0038] A seventh aspect of the invention is to provide a
planographic printing method comprising:
[0039] imagewise exposing a planographic printing plate precursor
comprising a hydrophilic support and a laser-sensitive
photopolymerizable layer disposed on the support to a laser
light;
[0040] attaching the planographic printing plate precursor to a
printing machine;
[0041] providing the planographic printing plate precursor with
moistening water and printing ink;
[0042] removing unexposed portions of the photopolymerizable layer;
and
[0043] using the obtained planographic printing plate for printing,
wherein the planographic printing plate precursor is capable of
forming image after exposure without being developed with an alkali
developer, and the photopolymerizable layer includes a polymer
having at least one ethylenic unsaturated bond on a side chain or
side chains thereof. The imagewise exposure may be conducted before
the attachment to the printing machine, or the attachment to the
printing machine may be conducted before the imagewise
exposure.
DETAILED DESCRIPTION OF THE INVENTION
[0044] The radical-crosslinkable polymer of the invention has a
polymerizable group and an alkyleneoxy group on a side chain or
side chains thereof. In the following, the radical-crosslinkable
polymer is described using an exemplary embodiment in which the
polymerizable group is a styrene group.
First Embodiment
[0045] In the following, a first embodiment of the invention is
described in detail.
Polymerizable Composition and Radical-Crosslinkable Polymer
[0046] The polymerizable composition of the first embodiment
includes a radical-crosslinkable alkali-soluble polymer (A) having
a styrene group and an alkyleneoxy group on a side chain or side
chains.
[0047] Preferably, the polymerizable composition further includes a
polymerizable compound and a polymerization initiator. It is
preferable to incorporate a sensitizing colorant to the
polymerizable composition from the viewpoint of sensitivity. In the
following, the radical crosslinkable alkali-soluble polymer (A)
(occasionally referred to as simply "specific polymer (A)"
hereinafter) having a styrene group and an alkyleneoxy group on a
side chain or side chains is described in detail.
Specific Polymer (A)
[0048] The specific polymer (A) of the first embodiment is not
particularly limited as long as a single molecule of the polymer
has a styrene group and an alkyleneoxy group on a side chain or
side chains. The structural unit of the specific polymer (A) may be
any known structural unit or a combination of known structural
units.
[0049] The glass transition point (Tg) of the specific polymer (A)
is preferably 60.degree. C. or lower from the viewpoints of
curability (printing durability) of exposed portions and
removability of unexposed portions. The glass transition point is
more preferably 50.degree. C. or lower, still more preferably
30.degree. C. or lower. The lower limit of the glass transition
point is preferably -50.degree. C.
[0050] The existence form of the styrene group and alkyleneoxy
group in the molecule is not particularly limited. For example, the
specific polymer (A) may be obtained by copolymerization of a
structural unit having a styrene group on a side chain thereof, a
structural unit having an alkyleneoxy group on a side chain
thereof, and other optional structural units. In another example,
the specific polymer (A) may be obtained by polymerization of a
structural unit having a styrene group and an alkyleneoxy group or
copolymerization of structural units including a structural unit
having a styrene group and an alkyleneoxy group. As an alternative,
such structures may be introduced to the main chain of a polymer as
side chains.
[0051] As described above, the glass transition point of the
specific polymer (A) is preferably 60.degree. C. or lower. In order
to adjust the glass transition point to the range, a structural
unit having a low glass transition point may be introduced into the
molecule.
[0052] The specific polymer (A) is preferably an organic
high-molecular-weight polymer which is soluble or swellable in
water or weakly alkaline water, whereby development with water or
weakly alkaline water is possible.
[0053] In the specific polymer (A), a styrene group is connected to
the main chain of the polymer directly or via a connecting group.
The connecting group is not particularly limited, and may be an
arbitrary connecting group, an atom such as N or O, or a
combination thereof. The phenyl group and vinyl group in the
styrene group each may have a substituent. The substituent may be,
for example, a halogen atom, a carboxyl group, a sulfo group, a
nitro group, a cyano group, an amide group, an amino group, an
alkyl group, an aryl group, an alkoxy group, or an aryloxy
group.
[0054] The specific polymer (A) may include a structural unit
having a side chain structure represented by the following formula
(S) as the side chain having a styrene group.
##STR00002##
[0055] In formula (S), Z.sup.1 represents a connecting group;
R.sup.1, R.sup.2, and R.sup.3 each independently represent a
hydrogen atom, a halogen atom, a carboxyl group, a sulfo group, a
nitro group, a cyano group, an amide group, an amino group, an
alkyl group, an aryl group, an alkoxy group, or an aryloxy group,
each of which may have a substituent such as an alkyl group, an
amino group, an aryl group, an alkenyl group, an carboxyl group, a
sulfo group, or a hydroxyl group; R.sup.4 represents a group or an
atom each of which is capable of being bonded to the benzene ring,
such as an alkyl group, an aryl group or a halogen atom which may
be a substituted oxy group, a substituted thio group, a substituted
amino group, or a substituted carbonyl group, and R.sup.4 may have
a substituent selected from the examples of substituents on
R.sup.1, R.sup.2, and R.sup.3; n represents 0 or 1; ml represents
an integer of 0 to 4; and k1 represents an integer of 1 to 4.
[0056] The connecting group represented by Z.sup.1 is preferably
--O`3, --S--, an alkylene group, an alkenylene group, an arylene
group, --N(R.sup.5)--, --C.dbd.(O)--O--, --C(R.sup.6).dbd.N--,
--C.dbd.(O)--, a sulfonyl group, a heterocyclic group, the group
described below, or a connecting group formed by combination of two
or more connecting groups which may be selected from the above
connecting groups. R.sup.5 and R.sup.6 each independently represent
a hydrogen atom, an alkyl group, or an aryl group.
##STR00003##
[0057] The above connecting groups each may have a substituent such
as an alkyl group, an aryl group, or a halogen atom.
[0058] The connecting group which connects a styrene structure to
the main chain is preferably has a structure containing a
heterocyclic group. The heterocyclic group may be a
nitrogen-containing heterocyclic group, a furan group, or a
thiophene group. Examples of the nitrogen-containing heterocyclic
group include a pyrrol ring, a pyrazol ring, an imidazole ring, a
triazole ring, a tetrazole ring, an isooxazole ring, an oxazole
ring, an oxadiazole ring, an isothiazole ring, a thiazole ring, a
thiadiazole ring, a thiatriazole ring, an indole ring, an indazole
ring, a benzimidazole ring, a benzotriazole ring, a benzoxazole
ring, a benzthiazole ring, a benzoselenazole ring, a
benzothiadiazole ring, a pyridine ring, a pyridazine ring, a
pyrimidine ring, a pyrazine ring, a triazine ring, a quinoline
ring, and a quinoxaline ring. Such heterocyclic groups each may
have a substituent and the substituent may be selected from halogen
atoms, carboxyl groups, sulfo groups, nitro groups, cyano groups,
amide groups, amino groups, alkyl groups, aryl groups, alkoxy
groups, and aryloxy groups.
[0059] Examples of a structural unit having the side-chain
structure which includes a styrene group and which is represented
by the above formula are shown below (K-1 to K-20). However, the
invention is not limited to those examples.
##STR00004## ##STR00005## ##STR00006##
[0060] The structural unit represented by formula (S) is preferably
a structural unit in which R.sup.1 and R.sup.2 are hydrogen atoms
and R.sup.3 is a hydrogen atom or an alkyl group having 4 or less
carbon atoms such as a methyl group or an ethyl group. The
connecting group is preferably a connecting group including a
heterocycle, and k1 is preferably 1 or 2.
[0061] Only a single type of structural unit represented by formula
(S) may be included in the specific polymer (A) or two or more
types of structural units represented by formula (S) may be
included in the specific polymer (A).
[0062] The proportion of the structural unit having a side-chain
structure represented by formula (S) to the total structural units
constituting the specific polymer (A) is preferably 1% by mol to
50% by mol, more preferably 1% by mol to 40% by mol. The content of
the structural unit having a side-chain structure represented by
formula (S) per 1 g of the specific polymer (A) is preferably 0.01
mmol to 7.0 mmol, more preferably 0.01 mmol to 5.0 mmol, still more
preferably 0.01 mmol to 4.0 mmol.
[0063] The specific polymer (A) may include a side-chain structural
unit represented by the following formula (AO) as the side chain
having an alkyleneoxy group.
##STR00007##
[0064] In formula (AO), Z.sup.A represents a connecting group;
R.sup.A1 represents an alkylene group; R.sup.A2 represents a
hydrogen atom, an alkyl group, or an aryl group; and n represents
an integer of 1 to 20.
[0065] The connecting group represented by Z.sup.A may be selected
from the connecting groups cited in the description of the
connecting group Z in formula (S).
[0066] The alkylene group represented by R.sup.A1 may be alkylene
group obtained by removing an arbitrary hydrogen atom form an alkyl
group having 1 to 20 carbon atoms. The alkylene group is preferably
a linear alkylene group having 1 to 12 carbon atoms, a branched
alkylene group having 3 to 12 carbon atoms, or a cyclic alkylene
group having 5 to 10 carbon atoms.
[0067] R.sup.A2 is preferably an alkyl group having 1 to 18 carbon
atoms, an aryl group having 6 to 18 carbon atoms, or a hydrogen
atom, more preferably an alkyl group having 1 to 3 carbon
atoms.
[0068] n is preferably an integer of 1 to 12, more preferably an
integer of 3 to 10.
[0069] Only a single type of structural unit represented by formula
(AO) may be included in the specific polymer (A), or two or more
types of structural units represented by formula (AO) may be
included in the specific polymer (A).
[0070] In the specific polymer (A), the proportion of the
structural unit represented by formula (AO) to the total structural
units constituting the specific polymer (A) is preferably 5% by mol
to 90% by mol, more preferably 20% by mol to 70% by mol.
[0071] The glass transition point (Tg) of the specific polymer (A)
is preferably 60.degree. C. or lower. The glass transition point of
the specific polymer (A) may be adjusted to the range by
incorporating a structural unit with a low Tg into the specific
polymer (A).
[0072] Preferable examples of the structural unit with a low Tg
include acrylate monomers and methacrylate monomers. The structural
unit with a low Tg is preferably a methacrylic ester of a
long-chain alkyl. The long-chain alkyl is preferably connected to
methacrylic acid via an ester group or an ether group.
[0073] The introduction of such a structural unit with a low Tg is
advantageous also from the viewpoints of curability (printing
durability) and removability of unexposed portions. Structural
units represented by the following formulae (I) to (IV) are
preferable as structural units having low Tgs.
##STR00008##
[0074] In formulae (I) to (IV), R.sup.1 represents an alkyl group,
preferably an alkyl group having 1 to 12 carbon atoms, more
preferably an alkyl group having 4 to 8 carbon atoms.
[0075] R.sup.2 represents an alkyl group having 4 to 12 carbon
atoms, preferably a linear alkyl group having 4 to 6 carbon
atoms.
[0076] R.sup.3 represents an alkylene group, preferably an alkylene
group having 2 to 6 carbon atoms. R.sup.4 represents an alkyl group
whose preferable examples are the same as in the case of the alkyl
group represented by R.sup.1.
[0077] R.sup.5 represents an alkylene group whose preferable
examples are the same as in the case of the alkylene group
represented by R.sup.3. R.sup.6 represents a hydrogen atom or an
alkyl group. When R.sup.6 represents an alkyl group, preferable
examples thereof are the same as in the case of the alkyl group
represented by R.sup.1.
[0078] Among formulae (I) to (IV), formula (IV) is included in the
scope of formula (AO). Accordingly, when the specific polymer (A)
includes an adequate amount of a structural unit represented by
formula (IV), the specific polymer (A) has a high sensitivity and
hydrophilicity owing to the alkyleneoxy group and also has high
printing durability and developability owing to the low Tg.
[0079] Only a single type of structural unit with a low Tg may be
used, or two or more types of structural units with low Tgs may be
used.
[0080] A structural unit represented by any of formulae (I) to (IV)
may be incorporated into the specific polymer (A) by adding the
structural unit to the copolymerization components of the specific
polymer (A) and conduct copolymerization by a usual radical
polymerization method.
[0081] The content of such a structural unit with a low Tg in the
specific polymer (A) is preferably 0% by mol to 60% by mol, more
preferably 10% by mol to 40% by mol.
[0082] In addition to the above-described side-chain structural
unit, the specific polymer (A) may further include a structural
unit having an alkali-soluble group on a side chain thereof. The
alkali-soluble group is preferably incorporated into the specific
polymer (A) by adding a structural unit having an alkali-soluble
group on a side chain thereof to copolymerization components. In
the structural unit having an alkali-soluble group as a
copolymerization component, the alkali-soluble group is preferably
selected from the following groups (1) to (6) from the viewpoint of
solubility of the specific polymer (A) in an alkaline developer.
The structural unit may include two or more such alkali-soluble
groups.
[0083] (1) Phenolic hydroxyl groups (--Ar--OH)
[0084] (2) Sulfonamide groups (--SO.sub.2NH--R)
[0085] (3) Substituted sulfonamide groups (occasionally referred to
as "active imide groups" hereinafter) (--SO.sub.2NHCOR,
--SO.sub.2NHSO.sub.2R, --CONHSO.sub.2R)
[0086] (4) Carboxylic acid groups (--CO.sub.2H)
[0087] (5) Sulfonic acid groups (--SO.sub.3H)
[0088] (6) Phosphoric acid groups (--OPO.sub.3H.sub.2)
[0089] In the above groups (1) to (6), Ar represents a divalent
aryl connecting group which may have a substituent, and R
represents a hydrogen atom or a hydrocarbon group which may have a
substituent.
[0090] The specific polymer (A) may further include other
structural units as copolymerization components for the purpose of
improving film properties, in addition to essential structural
units such as the structural unit having a side-chain structure
having a styrene group and a structural unit having an alkyleneoxy
group and the optional structural unit having an alkali-soluble
group.
[0091] Examples of such other structural units in the specific
polymer (A) include structural units derived from known monomers
such as arylic esters, methacrylic esters, acrylamides,
methacrylamides, vinylesters, styrenes, arylic acids, methacrylic
acids, acrylonitrile, maleic anhydride, and maleic imide.
[0092] Examples of the acrylic esters include methyl acrylate,
ethyl acrylate, (n- or i-)propyl acrylate, (n-, i-, sec- or
t-)butyl acrylate, amyl acrylate, 2-ethylhexyl acrylate, dodecyl
acrylate, chloroethyl acrylate, 2-hydroxyethyl acrylate,
2-hydroxypropyl acrylate, 5-hydroxypentyl acrylate, cyclohexyl
acrylate, allyl acrylate, trimethylolpropane monoacrylate,
pentaerythritol monoacrylate, glycidyl acrylate, benzyl acrylate,
methoxybenzyl acrylate, chlorobenzyl acrylate,
2-(p-hydroxyphenyl)ethyl acrylate, furfuryl acrylate,
tetrahydrofurfuryl acrylate, phenyl acrylate, chlorophenyl
acrylate, and sulfamoylphenyl acrylate.
[0093] Examples of the methacrylic esters include methyl
methacrylate, ethyl methacrylate, (n, or i-)propyl methacrylate,
(n, i-, sec- or t-)butyl methacrylate, amyl methacrylate,
2-ethylhexyl methacrylate, dodecyl methacrylate, chloroethyl
methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl
methacrylate, 5-hydroxypentyl methacrylate, cyclohexyl
methacrylate, allyl methacrylate, trimethylolpropane
monomethacrylate, pentaerythritol monomethacrylate, glycidyl
methacrylate, methoxybenzyl methacrylate, chlorobenzyl
methacrylate, 2-(p-hydroxyphenyl)ethyl methacrylate, furfuryl
methacrylate, tetrahydrofurfuryl methacrylate, phenyl methacrylate,
chlorophenyl methacrylate, and sulfamoylphenyl methacrylate.
[0094] Examples of the acrylamides include acrylamide,
N-methylacrylamide, N-ethylacrylamide, N-propylacrylamide,
N-butylacrylamide, N-benzylacrylamide, N-hydroxyethylacrylamide,
N-phenylacrylamide, N-tolylacrylamide,
N-(p-hydroxyphenyl)acrylamide, N-(sulfamoylphenyl)acrylamide,
N-(phenylsulfonyl)acrylamide, N-(tolylsulfonyl)acrylamide,
N,N-dimethylacrylamide, N-methyl-N-phenylacrylamide, and
N-hydroxyethyl-N-methylacrylamide.
[0095] Examples of the methacrylamides include methacrylamide,
N-methylmethacrylamide, N-ethylmethacrylamide,
N-propylmethacrylamide, N-butylmethacrylamide,
N-benzylmethacrylamide, N-hydroxyethylmethacrylamide,
N-phenylmethacrylamide, N-tolylmethacrylamide,
N-(p-hydroxyphenyl)methacrylamide,
N-(sulfamoylphenyl)methacrylamide,
N-(phenylsulfonyl)methacrylamide, N-(tolylsulfonyl)methacrylamide,
N,N-dimethylmethacrylamide, N-methyl-N-phenylmethacrylamide, and
N-hydroxyethyl-N-methylmethacrylamide.
[0096] Examples of the vinylesters include vinyl acetate, vinyl
butyrate and vinyl benzoate.
[0097] Examples of the styrenes include styrene, methylstyrene,
dimethylstyrene, trimethylstyrene, ethylstyrene, propylstyrene,
cyclohexylstyrene, chloromethylstyrene, trifluoromethylstyrene,
ethoxymethylstyrene, acetoxymethylstyrene, methoxystyrene,
dimethoxystyrene, chlorostyrene, dichlorostyrene, bromostyrene,
iodostyrene, fluorostyrene, and carboxystyrene.
[0098] Among these monomers, acrylic esters, methacrylic esters,
acrylamides, methacrylamides, vinylesters, styrenes, acrylic acids,
methacrylic acids and acrylonitriles each having 20 or less carbon
atoms are preferable.
[0099] In the following, specific examples (Q-1 to Q-15) of the
specific polymer (A) of the first embodiment are shown below.
However, the invention is not limited thereto. In the examples, Mw
represents the weight-average molecular weight of each polymer, and
Tg represents the glass transition point of each polymer. Further,
the ratio (% by weight) of each structural unit in each polymer is
also shown in the examples.
##STR00009## ##STR00010## ##STR00011## ##STR00012##
##STR00013##
[0100] The weight-average molecular weight of the specific polymer
(A) is selected in accordance with the intended use of the
polymerizable composition. Usually, the film property improves as
the molecular weight increases; however, image-forming property
upon polymerization and curing deteriorates as the molecular weight
increases. In contrast, when the molecular weight is low, the
image-forming property is improved, but film property (printing
durability) is deteriorated. The weight-average molecular weight of
the specific polymer (A) in the first embodiment is preferably 2000
to 1000000 from the viewpoints of sensitivity and film property,
more preferably 5000 to 500000, still more preferably 10000 to
300000.
[0101] Only a single type of specific polymer (A) may be used, or
two or more types of specific polymers (A) may be used. The amount
of the specific polymer may be 20% by weight to 80% by weight based
on the total solids of the polymerizable composition, preferably
30% by weight to 70% by weight based on the total solids of the
polymerizable composition.
[0102] As long as the effects of the invention are obtained, binder
polymers other than the specific polymer (A) may be used in
combination with the specific polymer (A). The amount of the other
polymers may be 1% by weight to 60% by weight based on the total
weight of the binder polymers, preferably 1% by weight to 40% by
weight based on the total weight of the binder polymers, more
preferably 1% by weight to 20% by weight based on the total weight
of the binder polymers. The other binder polymers may be selected
from known binder polymers without particular restrictions, and
examples thereof include binders each having an acrylic main chain
and urethane binders which are commonly used as film-forming
polymers of polymerizable compositions.
[0103] The total sum of the weight of the specific polymer and the
weights of other optional polymers in the polymerizable composition
may be suitably selected, and is usually 10% by weight to 90% by
weight based on the total weight of involatile components,
preferably 20% by weight to 80% by weight based on the total weight
of involatile components, more preferably 30% by weight to 70% by
weight based on the total weight of involatile components. These
ranges are also applicable in the recording layer of a planographic
printing plate precursor described later.
[0104] The planographic printing plate precursor of the invention
comprises a support and a laser-sensitive recording layer disposed
on the support, wherein the planographic printing plate precursor
can be used for printing without being subjected to an alkali
development, and the recording layer includes a polymer having a
polymerizable group on a side chain thereof. The support may be a
hydrophilic support.
Second Embodiment
[0105] In the following, the second embodiment of the invention is
described in detail.
[0106] The planographic printing plate precursor of the second
embodiment has a laser-sensitive photopolymerizable layer on a
hydrophilic support. The components in the photopolymerizable layer
are described in the following.
Photopolymerizable Layer
Polymer Having Ethylenic Unsaturated Bond on Side Chain
[0107] In the second embodiment, a polymer compound having at least
one ethylenic unsaturated bond on a side chain or side chains is
used as a binder resin from the viewpoints of film property of the
photopolymerizable layer and on-press developability. The polymer
compound having at least one ethylenic unsaturated bond on a side
chain or side chains is preferably a polymer compound having at
least one group selected from the groups represented by formulae
(1) to (3) below on a side chain or side chains thereof. This
polymer compound having at least one group selected from the groups
each represented by formula (1), (2), or (3) on a side chain or
side chains is occasionally referred to as "specific polymer (B)"
hereinafter.
##STR00014##
[0108] In the formulae, X and Y each independently represent an
oxygen atom, a sulfur atom, or --N--R.sup.12. Z represents an
oxygen atom, a sulfur atom, --N--R.sup.12, or a phenylene group.
R.sup.1 to R.sup.12 each independently represent a monovalent
substituent.
[0109] In formula (1), R.sup.1 to R.sup.3 each independently
represent a monovalent substituent. For example, R.sup.1 may be a
hydrogen atom or a monovalent organic group such as an alkyl group
which may be substituted. R.sup.1 is preferably a hydrogen atom, a
methyl group, a methylalkoxy group, or a methyl ester group.
R.sup.2 and R.sup.3 may each independently represent a hydrogen
atom, a halogen atom, an amino group, a dialkylamino group, a
carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro
group, a cyano group, an alkyl group which may be substituted, an
aryl group which may be substituted, an alkoxy group which may be
substituted, an aryloxy group which may be substituted, an
alkylamino group which may be substituted, an arylamino group which
may be substituted, an alkylsulfonyl group which may be
substituted, or an arylsulfonyl group which may be substituted.
R.sup.2 and R.sup.3 are each preferably a hydrogen atom, a carboxyl
group, an alkoxycarbonyl group, an alkyl group which may be
substituted, or an aryl group which may be substituted. The
substituent to be introduced may be a methoxycarbonyl group, an
ethoxycarbonyl group, an isopropoxycarbonyl group, a methyl group,
an ethyl group or a phenyl group. X represents an oxygen atom, a
sulfur atom, or --N--R.sup.12, and R.sup.12 may be an alkyl group
which may be substituted.
[0110] In formula (2), R.sup.4 to R.sup.8 each independently
represent a monovalent substituent, and examples thereof include a
hydrogen atom, a halogen atom, an amino group, a dialkylamino
group, a carboxyl group, an alkoxy carbonyl group, a sulfo group, a
nitro group, a cyano group, an alkyl group which may be
substituted, an aryl group which may be substituted, an alkoxy
group which may be substituted, an aryloxy group which may be
substituted, an alkylamino group which may be substituted, an
arylamino group which may be substituted, an alkylsulfonyl group
which may be substituted, or an arylsulfonyl group which may be
substituted. R.sup.4 and R.sup.8 are each preferably a hydrogen
atom, a carboxyl group, an alkoxycarbonyl group, an alkyl group
which may be substituted, or an aryl group which may be
substituted. The substituent to be introduced may be a
methoxycarbonyl group, an ethoxycarbonyl group, an
isopropoxycarbonyl group, a methyl group, an ethyl group or a
phenyl group. Y represents an oxygen atom, a sulfur atom, or
--N--R.sup.12, and R.sup.12 may be an alkyl group which may be
substituted.
[0111] In formula (3), R.sup.9 to R.sup.11 each independently
represent a monovalent substituent, and examples thereof include a
hydrogen atom, a halogen atom, an amino group, a dialkylamino
group, a carboxyl group, an alkoxy carbonyl group, a sulfo group, a
nitro group, a cyano group, an alkyl group which may be
substituted, an aryl group which may be substituted, an alkoxy
group which may be substituted, an aryloxy group which may be
substituted, an alkylamino group which may be substituted, an
arylamino group which may be substituted, an alkylsulfonyl group
which may be substituted, or an arylsulfonyl group which may be
substituted. R.sup.9 and R.sup.11 are each preferably a hydrogen
atom, a carboxyl group, an alkoxycarbonyl group, an alkyl group
which may be substituted, or an aryl group which may be
substituted. The substituent to be introduced may be a
methoxycarbonyl group, an ethoxycarbonyl group, an
isopropoxycarbonyl group, a methyl group, an ethyl group or a
phenyl group. Z represents an oxygen atom, a sulfur atom,
--N--R.sup.12, or a phenylene group, and R.sup.12 may be an alkyl
group which may be substituted.
[0112] Among the specific polymers (B), compounds having groups
represented by (1) on side chains can be synthesized by at least
one of the following methods (1) and (2).
Synthesis Method (1)
[0113] This method comprises: synthesizing a polymer compound by
polymerization of a at least one of radical-polymerizable compounds
each represented by the following formula (4) or (5); and treating
the polymer compound with a base to cause an elimination reaction
such that X.sup.1 and Z.sup.1 in the formula are eliminated,
thereby obtaining the desired polymer compound.
##STR00015##
[0114] In the formulae, X.sup.1 and Z.sup.1 each independently
represent a dissociative group which is to be removed by the
elimination reaction. In the elimination reaction, Z.sup.1 is
pulled out by action of the base, and X.sup.1 is eliminated.
Preferably, X.sup.1 is a group which can dissociate as an anion and
Z.sup.1 is a group which can dissociate as a cation.
[0115] Examples of the group represented by X.sup.1 include halogen
atoms, sulfonic acid groups, sulfinic acid groups, carboxyl groups,
cyano groups, ammonium groups, azide groups, sulfonium groups,
nitro groups, hydroxyl groups, alkoxy groups, phenoxy groups,
thioalkoxy groups, and oxonium groups. X.sup.1 is preferably a
halogen atom, a sulfonic acid group, an ammonium group or a
sulfonium group. X.sup.1 is more preferably a chlorine atom, a
bromine atom, an iodine atom, an alkylsulfonic acid group, or an
arylsulfonic acid group. Examples of the alkylsulfonic acid groups
include a methane sulfonic acid group, an ethane sulfonic acid
group, a 1-propane sulfonic acid group, an isopropyl sulfonic acid
group, a 1-butane sulfonic acid group, a 1-octyl sulfonic acid
group, a 1-hexadecane sulfonic acid group, a trifluoromethane
sulfonic acid group, a trichloromethan sulfonic acid group, a
2-chloro-1-ethane sulfonic acid group, a 2,2,2,-trifluoroethane
sulfonic acid group, a 3-chloropropane sulfonic acid group, a
perfluoro-1-butane sulfonic acid group, a perfuluoro-1-octane
sulfonic acid group, a 10-camphor sulfonic acid group, and a benzyl
sulfonic acid group. Examples of the arylsulfonic acid group
include benzene sulfonic acid group, a trans-.beta.-styrene
sulfonic acid group, a 2-nitrobenzene sulfonic acid group, a
2-acetylbenzene sulfonic acid group, a 3-(trifluoromethyl)benzene
sulfonic acid group, a 3-nitrobenzene sulfonic acid group, a
4-nitrobenzene sulfonic acid group, a p-toluene sulfonic acid
group, a 4-tert-butylbenzene sulfonic acid group, a 4-fluorobenzene
sulfonic acid group, a 4-chlorobenzene sulfonic acid group, a
4-bromobenzene sulfonic acid group, a 4-iodobenzene sulfonic acid
group, a 4-methoxybenzene sulfonic acid group, a
4-(trifluoromethoxy)benzene sulfonic acid group, a
2,5-dichlorobenzene sulfonic acid group, a
2-nitro-4-(trifluoromethyl)-benzene sulfonic acid group, a
4-chloro-3-nitrobenzene sulfonic acid group, a 2,4-dinitrobenzene
sulfonic acid group, a 2-mesitylene sulfonic acid group, a
2,4,6-triisopropylbenzene sulfonic acid group, a pentafluorobenzene
sulfonic acid group, a 1-naphthalene sulfonic acid group, and a
2-naphthalene sulfonic acid group.
[0116] Z.sup.1 may be, for example, a hydrogen atom, a halogen
atom, an ammonium group, a sulfonium group, a phosphonium group, or
an oxonium group, preferably a hydrogen atom. When Z.sup.1 is a
hydrogen atom, the base pulls out the proton, thus causing the
elimination of X.sup.1.
[0117] In the second embodiment, a combination of X.sup.1 and
Z.sup.1 is preferably such a combination that X.sup.1 is a halogen
atom and Z.sup.1 is a hydrogen atom. In this case, X.sup.1 leaves
as an anion and Z.sup.1 leaves as a cation.
[0118] In formulae (4) and (5), R.sup.13 may be, for example, a
hydrogen atom or an alkyl group which may be substituted,
preferably a hydrogen atom, a methyl group, a methylalkoxy group or
a methylester group. Q represents an oxygen atom, --NH--, or
NR.sup.14-- and R.sup.14 represents an alkyl group which may be
substituted. A represents a divalent organic connecting group.
[0119] In formulae (4) and (5), the divalent organic connecting
group represented by A is preferably comprised of a combination of
1 to 60 carbon atom(s), 0 to 10 nitrogen atom(s), 0 to 50 oxygen
atom(s), 1 to 100 hydrogen atom(s), and 0 to 20 sulfur atom(s).
Specific examples of the connecting group include connecting groups
each comprised of a combination of the following structural
units.
##STR00016##
(Base Used for Elimination Reaction)
[0120] In the method for synthesizing a polymer compound having at
least one group represented by formula (1) on a side chain or side
chains, a treatment with a base causes an elimination reaction of a
specific functional group to remove X.sup.1 and Z.sup.1 in formula
(1), thereby obtaining a radical-reactive group. The base used in
the elimination reaction is preferably an alkali metal hydride, an
alkali metal hydroxide, an alkali metal carbonate, an organic amine
compound, or a metal alkoxide compound.
[0121] Examples of the hydride, hydroxide, and carbonate of an
alkali metal include sodium hydride, calcium hydride, potassium
hydride, sodium hydroxide, potassium hydroxide, calcium hydroxide,
potassium carbonate, sodium carbonate, potassium hydrogen
carbonate, and sodium hydrogen carbonate.
[0122] Examples of the organic amine compound include
trimethylamine, triethylamine, diethylmethylamine, tributylamine,
triisobutylamine, trihexylamine, trioctylamine,
N,N-dimethylcyclohexylamine, N,N-diethylcyclohexylamine,
N-methyldicyclohexylamine, N-ethyldicyclohexylamine, pyrrolidine,
1-methylpyrrolidine, 2,5-dimethylpyrrolidine, piperidine,
1-methylpiperidine, 2,2,6,6-tetramethylpiperidine, piperazine,
1,4-dimethylpiperazine, quinuclidine,
1,4-diazabicyclo[2,2,2]-octane, hexamethylenetetramine, morpholine,
4-methylmorpholine, pyridine, picoline, 4-dimethylaminopyridine,
lutidine, 1,8-diazabicyclo[5,4,0]-7-undecene (DBU),
N,N'-dicyclohexylcarbodiimide (DCC), diisopropylethylamine, and a
Schiff base.
[0123] Examples of the metal alkoxide compound include sodium
methoxide, sodium ethoxide, and potassium t-butoxide. Only a single
base compound may be used, or a mixture of two or more base
compounds may be used.
[0124] In the elimination reaction, the solvent for adding the base
may be, for example, ethylene dichloride, cyclohexanone, methyl
ethyl ketone, acetone, methanol, ethanol, propanol, butanol,
ethyleneglycol monomethyl ether, ethyleneglycol monoethyl ether,
2-methoxyethyl acetate, 1-methoxy-2-propanol, 1-methoxy-2-propyl
acetate, N,N-dimethylformamide, N,N-dimethylacetamide,
dimethylsulfoxide, toluene, ethyl acetate, methyl lactate, ethyl
lactate, or water. Only a single type of solvent may be used, or
two or more types of solvents may be used in combination.
[0125] The amount of the base to be used may be not larger than an
amount equivalent to the amount of the specific functional groups
in the compound, or may be not smaller than the amount equivalent
to the amount of the specific functional groups in the
compound.
[0126] When an excessive amount of a base is used, it is preferable
to add an acid or the like after the elimination reaction so as to
remove the excessive base. The acid may be an inorganic acid such
as hydrochloric acid, sulfuric acid, nitric acid, hydrobromic acid,
and perchloric acid, or an organic acid such as acetic acid,
fluoroacetic acid, trifluoroacetic acid, methanesulfonic acid,
p-toluenesulfonic acid, and trifluoromethanesulfonic acid.
[0127] The temperature at the elimination reaction may be room
temperature, a lowered temperature, or an elevated temperature. The
temperature is preferably -20.degree. C. to 100.degree. C.
[0128] Examples of radical-polymerizable compounds each represented
by formula (4) or (5) are shown below, but the examples should not
be construed as limiting the invention.
##STR00017## ##STR00018## ##STR00019## ##STR00020## ##STR00021##
##STR00022## ##STR00023## ##STR00024## ##STR00025##
Synthesis Method (2)
[0129] This method comprises: synthesizing a trunk polymer compound
(compound constituting the main chain) by polymerization of at
least one radical polymerizable compound having a functional group;
and allowing a functional group on a side chain of the trunk
polymer compound to react with a compound having a structure
represented by the following formula (6).
##STR00026##
[0130] The functional group on the radical polymerizable compound
used for the synthesis of the trunk polymer compound in the
synthesis method (2) may be, for example, a hydroxyl group, a
carboxyl group, a carboxylic acid halide group, an anhydrous
carboxylic acid group, an amino group, a halogenated alkyl group,
an isocyanate group, or an epoxy group. The radical polymerizable
compound having such a functional group may be, for example,
2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate,
4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, acrylic acid,
methacrylic acid, acrylic acid chloride, methacrylic acid chloride,
methacrylic acid anhydride, N,N-dimethyl-2-aminoethyl methacrylate,
2-chloroethyl methacrylate, 2-isocyanic acid ethyl methacrylate,
glycidyl acrylate, or glycidyl methacrylate. In the method,
polymerization of at least one type of radical-polymerizable
compound described above is conducted while other
radical-polymerizable compounds may be optionally added, so as to
form a trunk polymer compound, and then a compound having a group
represented by formula (6) is allowed to react with the trunk
polymer compound to form the desired polymer compound. Examples of
the compound having a group represented by formula (6) include the
above-described examples of the radical-polymerizable compound
having a functional group.
[0131] A specific polymer (B) having a group represented by formula
(2) can be synthesized by at least one of the following synthesis
methods (3) and (4).
Synthesis Method (3)
[0132] This method comprises: polymerizing at least one
radical-polymerizable compound having a first unsaturated group
represented by formula (2) and a second ethylenic unsaturated group
with higher addition-polymerizability than the first unsaturated
group while optionally adding other radical-polymerizable compound,
so as to form a polymer compound. This method uses a compound
having two or more ethylenic unsaturated group with different
addition-polymerizability, such as an allyl methacrylate.
Synthesis Method (4)
[0133] This method comprises: polymerizing at least one
radical-polymerizable compound having a functional group to form a
polymer compound; and then allowing the functional group on a side
chain to react with a compound having a structure represented by
the following formula (7) so as to incorporate a group represented
by formula (2) into the polymer compound.
##STR00027##
[0134] The radical-polymerizable compound having a first
unsaturated group represented by formula (2) and a second ethylenic
unsaturated group with a higher addition-polymerizability than the
first unsaturated group may be, for example, allyl acrylate, allyl
methacrylate, 2-allyloxyethyl acrylate, propargyl acrylate,
propargyl methacrylate, N-allyl acrylate, N-allyl methacrylate,
N,N-diallyl acrylate, N,N-diallyl methacrylate, allyl acrylamide,
or allyl methacrylamide. Examples of the polymer compound obtained
by polymerizing at least one radical-polymerizable compound having
a functional group include the examples of the
radical-polymerizable group having a functional group described in
the synthesis example (2).
[0135] The compound having a structure represented by formula (7)
may be allyl alcohol, allyl amine, diallyl amine, 2-allyloxyethyl
alcohol, 2-chloro-1-butene, or allyl isocyanate.
[0136] A specific polymer compound (B) having a group represented
by formula (3) on a side chain can be synthesized by at least one
of the following synthesis methods (5) and (6).
Synthesis Method (5)
[0137] This method comprises: polymerizing at least one
radical-polymerizable compound having a first unsaturated group
represented by formula (3) and a second ethylenic unsaturated group
with higher addition-polymerizability than the first unsaturated
group while optionally adding other radical-polymerizable compound,
so as to form a polymer compound.
Synthesis Method (6)
[0138] This method comprises: polymerizing at least one
radical-polymerizable compound having a functional group to form a
polymer compound; and then allowing the functional group on a side
chain to react with a compound having a structure represented by
the following formula (8) so as to incorporate a group represented
by formula (3) into the polymer compound.
##STR00028##
[0139] The radical-polymerizable compound having a first
unsaturated group represented by formula (3) and a second ethylenic
unsaturated group with a higher addition-polymerizability than the
first unsaturated group may be, for example, vinyl acrylate, vinyl
methacrylate, 2-phenylvinyl acrylate, 2-phenylvinyl methacrylate,
1-propenyl acrylate, 1-propenyl methacrylate, vinyl acrylamide, or
vinyl methacrylamide. Examples of the polymer compound obtained by
polymerizing at least one radical-polymerizable compound having a
functional group include the examples of the radical-polymerizable
group having a functional group described in the synthesis example
(2). The compound having a structure represented by formula (8) may
be 2-hydroxyethyl monovinyl ether, 4-hydroxybutyl monovinyl ether,
diethylene glycol monovinyl ether, or 4-chloromethylstyrene.
(Thermal Polymerization Inhibitor)
[0140] In the synthesis methods of specific polymer (B), it is
preferable to use a thermal polymerization inhibitor in order to
inhibit thermal radical reaction of the generated radical-reactive
group. The thermal polymerization inhibitor may be hydroquinone,
p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butyl catecol,
benzoquinone, 4,4'-thiobis(3-methyl-6-t-butylphenol),
2,2'-methylene bis(4-methyl-6-t-butylphenol),
N-nitroso-N-phenylhydroxylamine aluminum salt,
2,2,6,6,-tetramethylpyperidine-1-oxyl-(TEMPO), 4-hydroxy-TEMPO free
radical, 3,3,5,5-tetramethyl-1-pyrroline-N-oxide,
4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl, 3-(aminomethyl)proxyl
free radical, 3-carboxy-proxyl free radical, 4-amino-TEMPO free
radical, 4-carboxy-TEMPO free radical, a thiosulfate compound, a
ferrocene compound, a thiol compound, a sulfide compound, a
disulfide compound, or a borate salt compound. The amount of the
thermal polymerization inhibitor is 10 ppm to 10% by weight based
on the weight of the reaction system.
[0141] Preferably, the specific polymer (B) does not have an
alkali-soluble group. A radical-polymerizable compound having a
hydrophilic group may be included in the specific polymer (B) as a
copolymerization component for the purpose of improving on-press
developability or the like. The hydrophilic group may be an amide
group, a hydroxyl group, an ether group, or an onium salt group,
preferably a sulfonic acid group, an amide group, a hydroxyl group
or an ether group. Examples of the radical-polymerizable compound
having a hydrophilic group include acrylamide, methacrylamide,
N,N-dimethylacrylamide, N-isopropylacrylamide, N-vinyl pyrrolidone,
N-vinyl acetoamide, N-acryloyl morpholine, 2-hydroxyethyl acrylate,
2-hydroxyethyl methacrylate, glycerol monomethacrylate, glycerol
monoacrylate, methoxypolyethyleneglycol monomethacrylate,
methoxypolyethyleneglycol monoacrylate, polyethyleneglycol
monomethacrylate, polyethyleneglycol monoacrylate, polypropylene
glycol monomethacrylate, polypropyleneglycol monoacrylate,
polyethyleneglycol-polypropyleneglycol monomethacrylate,
polyethyleneglycol-polypropyleneglycol monoacrylate,
poly(ethyleneglycol-tetramethyleneneglycol)monomethacrylate,
poly(ethyleneglycol-tetramethyleneglycol)monoacrylate,
poly(propyleneglycol-tetramethyleneglycol)monomethacrylate, and
poly(propyleneglycol-tetramethyleneglycol)monoacrylate. A single
type of radical-polymerizable compound having a hydrophilic group
may be added, or two or more types of such compounds may be added.
The proportion of the radical-polymerizable compound having a
hydrophilic group to the entire copolymer is preferably 0 to 85% by
mol, more preferably 5 to 70% by mol.
[0142] It is preferable to incorporate other radical-polymerizable
compounds than those described above into the specific polymer (B)
as copolymerization components for the purpose of improving
properties such as image strength as long as the effect of the
invention is maintained. The radical-polymerizable compounds which
can be included in the specific polymer (B) as copolymer components
may be selected from acrylic esters, methacrylic esters,
N,N-bis-substituted acrylamides, N,N-bis-substituted
methacrylamides, styrenes, acrylonitriles, and
methacrylonitrils.
[0143] Examples of the radical-polymerizable compounds which can be
included in the specific polymer (B) as copolymer components
include: acrylic esters such as alkyl acrylates (the number of
carbon atoms in the alkyl group is preferably 1 to 20, and the
alkyl acrylates include methyl acrylate, ethyl acrylate, propyl
acrylate, butyl acrylate, amyl acrylate, ethylhexyl acrylate, octyl
acrylate, t-octyl acrylate, chloroethyl acrylate,
2,2-dimethylhydroxypropyl acrylate, 5-hydroxypentyl acrylate,
trimethylolpropane monoacrylate, pentaerythritol monoacrylate,
glycidyl acrylate, benzyl acrylate, methoxybenzyl acrylate,
furfuryl acrylate, and tetrahydrofurfuryl acrylate); aryl acrylates
such as phenyl acrylate; methacrylic esters such as alkyl
methacrylates (the number of carbon atoms in the alkyl group is
preferably 1 to 20, and the alkyl methacrylates include methyl
methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl
methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl
methacrylate, benzyl methacrylate, chlorobenzyl methacrylate, octyl
methacrylate, 4-hydroxybutyl methacrylate, 5-hydroxypentyl
methacrylate, 2,2-dimethyl-3-hydroxypropyl methacrylate,
trimethylolpropane monomethacrylate, pentaerythritol
monomethacrylate, glycidyl methacrylate, furfuryl methacrylate, and
tetrahydrofurfuryl methacrylate); aryl methacrylates such as phenyl
methacrylate, cresyl methacrylate, and naphtyl methacrylate;
styrenes such as styrene and alkyl styrenes (examples thereof
include methylsyrene, dimethylstyrene, trimethylstyrene,
ethylstyrene, diethylstyrene, isopropylstyrene, butylstyrene,
hexylstyrene, cyclohexylstyrene, decylstyrene, benzylstyrene,
chloromethylstyrene, trifluoromethylstyrene, ethoxymethylstyrene,
and acetoxymethylstyrene); alkoxy styrenes such as methoxystyrene,
4-methoxy-3-methylstyrene, and dimethoxystyrene; halogen styrenes
such as chlorostyrene, dichlorostyrene, trichlorostyrene,
tetrachlorostyrene, pentachlorostyrene, bromostyrene,
dibromostyrene, iodostyrene, fluorostyrene, trifluorostyrene,
2-bromo-4-trifluoromethylstyrene, and
4-fluoro-3-trifluoromethylstyrene; acrylonitrile; and
methacrylonitrile. Among them, acrylic esters, methacrylic esters
and styrenes are preferable. Only one radical-polymerizable
compound or two or more radical-polymerizable compounds may be
copolymerized with the compound having a group represented by
formula (1), (2), or (3). The proportion of such other
radical-polymerizable compounds in the specific polymer (B) is 0 to
95% by mol, more preferably 20 to 90% by mol.
[0144] The specific polymer (B) may be a homopolymer, or a
copolymer of some radical-polymerizable compounds each having a
group represented by formula (1), (2), or (3), or a copolymer of at
least one radical-polymerizable compound having a group represented
by formula (1), (2), or (3) and at least one such other
radical-polymerizable compound as described above. When the
specific polymer (B) is a copolymer, the copolymer may be a block
copolymer, a random copolymer or a graft copolymer.
[0145] The solvent to be used for synthesis of the specific polymer
(B) may be, for example, ethylene dichloride, cyclohexanone, methyl
ethyl ketone, acetone, methanol, ethanol, propanol, butanol,
ethyleneglycol monomethyl ether, ethyleneglycol monoethyl ether,
2-methoxyethyl acetate, 1-methoxy-2-propanol, 1-methoxy-2-propyl
acetate, N,N-dimethyl formamide, N,N-dimethyl acetoamide, dimethyl
sulfoxide, toluene, ethyl acetate, methyl lactate, or ethyl
lactate. Only a single solvent may be used, or a mixture of two or
more solvents may be used.
[0146] The specific polymer (B) has a weight-average molecular
weight of preferably 2,000 or larger, more preferably 5,000 to
300,000. The specific polymer (B) may include unreacted monomers.
The content of the unreacted monomers in the specific polymer (B)
is preferably 15% by weight or lower.
[0147] The content of the specific polymer (B) in the planographic
printing plate precursor of the second embodiment is preferably 5
to 95% by mass based on the solid content of the photopolymerizable
layer, more preferably 10 to 85% by mass based on the solid content
of the photopolymerizable layer. When the content of the specific
polymer (B) is in the above ranges, the strength of image portions
and image-forming property are improved.
[0148] The photopolymerizable layer of the second embodiment may
further include the specific polymer (A) described above. In this
case, preferable examples of the specific polymer (A) are the same
as in the first embodiment.
Polymerizable Compound
[0149] A polymerizable compound may be used in the polymerizable
composition of the first embodiment or in the photopolymerizable
layer of the second embodiment. The polymerizable compound is an
addition-polymerizable compound having at least one ethylenic
unsaturated double bond. The number of ethylenic unsaturated bond
in the polymerizable compound is at least one, preferably two or
more. Such a compound is well-known in the art, and is not
particularly limited. The polymerizable compound may be a monomer,
a prepolymer such as a dimer, a trimer, or an oligomer, or a
mixture thereof, or a copolymer thereof. The monomer or copolymer
of monomers may be, for example, an unsaturated carboxylic acid
(such as acrylic acid, methacrylic acid, itaconic acid, crotonic
acid, isocrotonic acid or maleic acid), or an ester or amide of
such an unsaturated carboxylic acid, and is preferably: an ester of
an unsaturated carboxylic acid and an aliphatic polyhydric alcohol;
an amide of an unsaturated carboxylic acid and an aliphatic
polyamine; a product of an addition-reaction between an unsaturated
carboxylic ester or amide having a nucleophilic substituent such as
a hydroxyl group, an amino group, and a mercapto group, and a
monofunctional or polyfunctional isocyanate or epoxy; a product of
dehydration-condensation of such an unsaturated carboxylic ester or
amide having a nucleophilic group and a monofunctional or
polyfunctional carboxylic acid; a product of an addition-reaction
between an unsaturated carboxylic ester or amide having an
electrophilic substituent such as isocyante group or an epoxy group
and a monofunctional or polyfunctional alcohol, amine, or thiol; or
a product of substitution reaction of an unsaturated carboxylic
ester or amide having a dissociative group such as a halogen group
or a tosyloxy group with a monofunctional or polyfunctional
alcohol, amine or thiol. The unsaturated carboxylic acid used in
the above examples may be replaced by an unsaturated phosphonic
acid, styrene, or a vinyl ether.
[0150] When the monomer is an ester between an aliphatic polyhydric
alcohol and an unsaturated carboxylic acid, examples of the monomer
include: acrylic esters such as ethyleneglycol diacrylate,
triethyleneglycol diacrylate, 1,3-butanediol diacrylate,
tetramethyleneglycol diacrylate, propyleneglycol diacrylate,
neopentylglycol diacrylate, trimethylolpropane triacrylate,
trimethylolpropane tri(acryloyloxypropyl)ether, trimethylolethane
triacrylate, hexanediol diacrylate, 1,4-cyclohexanediol diacrylate,
tetraethyleneglycol diacrylate, pentaerythritol diacrylate,
pentaerythritol triacrylate, pentaerythritol tetraacrylate,
dipentaerythritol diacrylate, dipentaerythritol hexaacrylate,
sorbitol triacrylate, sorbitol tetraacrylate, sorbitol
pentaacrylate, sorbitol hexaacrylate,
tri(acryloyloxyethyl)isocyanurate, and polyester acrylate oligomer
isocyanurate EO-modified triacrylate; methacrylic esters such as
tetramethylene glycol dimethacrylate, triethylene glycol
dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane
trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol
dimethacrylate, 1,3-butanediol dimethacrylate, hexanediol
dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol
trimethacrylate, pentaerythritol tetramethacrylate,
dipentaerythritol dimethacrylate, dipentaerythritol
hexamethacrylate, sorbitol trimethacrylate, sorbitol
tetramethacrylate, bis
[p-(3-methacryloxy-2-hydroxypropoxy)phenyl]dimethylmethane, and
bis[p-(acryloxyethoxy)phenyl]dimethylmethane; itaconic esters such
as ethylene glycol diitaconate, propylene glycol diitaconate,
1,3-butanediol diitaconate, 1,4-butanediol diitaconate,
tetramethylene glycol diitaconate, pentaerythritol diitaconate, and
sorbitol tetraitaconate; crotonic esters such as ethylene glycol
dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol
dicrotonate, and sorbitol tetracrotonate; isocrotonic esters such
as ethylene glycol diisocrotonate, pentaerythritol diisocrotonate,
and sorbitol tetraisocrotonate; maleic esters such as ethylene
glycol dimaleate, triethylene glycol dimaleate, pentaerythritol
dimaleate, and sorbitol tetramaleate; and mixtures of two or more
ester monomers which may be selected from the above ester
monomers.
[0151] Other examples of esters include esters of aliphatic
alcohols described in JP-B No. 51-47334 and JP-A No. 57-196231 (the
disclosures of which are incorporated herein by reference), esters
having aromatic skeletons described in JP-A Nos. 59-5240, 59-5241,
and 2-226149 (the disclosures of which are incorporated herein by
reference), and esters having amino groups described in JP-A No.
1-165613 (the disclosure of which is incorporated herein by
reference). A mixture of ester monomers can also be used.
[0152] When the monomer is an amide between an aliphatic polyamine
compound and an unsaturated carboxylic acid, examples thereof
include methylene bisacrylamide, methylene bismethacrylamide,
1,6-hexamethylene bisacrylamide, 1,6-hexamethylene
bismethacrylamide, diethylenetriamine trisacrylamide, xylylene
bisacrylamide and xylylene bismethacrylamide. Amide monomers having
cyclohexylene structures disclosed in JP-B No. 54-21726 (the
disclosure of which is incorporated herein by reference) are also
preferable.
[0153] Urethane-based addition-polymerizable compounds each
prepared by addition-reaction between an isocyanate and a hydroxyl
group are also preferable and example thereof include vinylurethane
compounds described in JP-B No. 48-41708 (the disclosure of which
is incorporated by reference herein) which each have two or more
polymerizable vinyl groups and which are each obtained by adding a
vinyl monomer having a hydroxyl group represented by the following
formula (A) to a polyisocyanate compound having two or more
isocyanate groups.
CH.sub.2.dbd.C(R.sup.V1)COOCH.sub.2CH(R.sup.V2)OH Formula (A)
[0154] In formula (A), R.sup.V1 and R.sup.V2 each independently
represent H or CH.sub.3.
[0155] Other examples of the monomer include: urethane acrylates
disclosed in JP-A No. 51-37193 and JP-B Nos. 2-32293 and 2-16765
(the disclosures of which are incorporated herein by reference);
urethane compounds having ethylene oxide skeletons such as urethane
compounds disclosed in JP-B Nos. 58-49860, 56-17654, 62-39417, and
62-39418 (the disclosures of which are incorporated herein by
reference); addition-polymerizable compounds having an amino
structure or a sulfide structure disclosed in JP-A Nos. 63-277653,
63-260909, and 1-105238 (the disclosures of which are incorporated
herein by reference), which enables remarkably quick exposure of
the photopolymerizable composition or photopolymerizable layer.
[0156] Still other examples of the monomer include: polyester
acrylates such as polyester acrylates disclosed in JP-A No.
48-64183 and JP-B Nos. 49-43191 and 52-30490 (the disclosures of
which are incorporated herein by reference); polyfunctional
acrylates and methacrylates such as epoxy acrylates obtained by a
reaction of an epoxy resin and (meth)acrylic acid; unsaturated
compounds disclosed in JP-B Nos. 46-43946, 1-40337, and 1-40336
(the disclosures of which are incorporated herein by reference);
vinylphosphonic acid compounds disclosed in JP-A No. 2-25493 (the
disclosure of which is incorporated herein by reference); monomers
having perfluoroalkyl groups disclosed in JP-A No. 61-22048 (the
disclosure of which is incorporated herein by reference); and
photocurable monomer and oligomer disclosed in Nihon Secchaku
Kyoukaishi vol. 20 (1984), No. 7, pp. 300 to 308, the disclosure of
which is incorporated herein by reference.
[0157] The polymerizable compound may be a polyfunctional styrene
crosslinking agent represented by the following formula, which is
described in JP-A No. 2001-290271, pp. 13 to 14, the disclosure of
which is incorporated herein by reference. This polyvalent styrene
crosslinking agent has two or more phenyl groups each having a
vinyl group. When such a polyvalent styrene crosslinking agent is
used, styryl radicals are generated by a polymerization initiator,
and then the styryl radicals combine with each other, so that the
polymerizable composition or the photopolymerizable layer is
crosslinked, thereby achieving higher sensitivity.
##STR00029##
[0158] In the formula, Z.sup.2 represents a connecting group,
R.sup.21, R.sup.22, and R.sup.23 each independently represent a
hydrogen atom, a halogen atom, a carboxyl group, a sulfo group, a
nitro group, a cyano group, an amide group, an amino group, an
alkyl group, an aryl group, an alkoxy group, or an aryloxy group,
each of which may be substituted by an alkyl group, an amino group,
an aryl group, an alkenyl group, a carboxyl group, a sulfo group, a
hydroxyl group, or the like. R.sup.24 represent a group or atom
which can be bonded to the benzene ring. m.sup.2 represents an
integer of 0 to 4, and k.sup.2 represents an integer of 2 or
larger.
[0159] The connecting group represented by Z.sup.2 may be --O--,
--S--, an alkylene group, an alkenylene group, an arylene group,
--N(R.sup.5)--, --C.dbd.(O)--O--, --C(R.sup.6).dbd.N--,
--C.dbd.(O)--, a sulfonyl group, a heterocyclic group, or a
connecting group comprised of a combination of two or more
connecting groups which may be selected from the above connecting
groups. R.sup.5 and R.sup.6 each independently represent a hydrogen
atom, an alkyl group, or an aryl group. The connecting group
represented by Z.sup.2 may have a substituent such as an alkyl
group, an aryl group, or a halogen atom.
[0160] When the connecting group represented by Z.sup.2 contains a
heterocyclic group, the heterocyclic group may be a
nitrogen-containing heterocyclic ring such as a pyrrole ring, a
pyrazole ring, an imidazole ring, a triazole ring, a tetrazole
ring, an isooxazole ring, an oxazole ring, an oxadiazole ring, an
isothiazole ring, a thiazole ring, a thiadiazole ring, a
thiatriazole ring, an indole ring, an indazole ring, a
benzimidazole ring, a benzotriazole ring, a benzoxazole ring, a
benzthiazole ring, a benzoselenazole ring, a benzothiadiazole ring,
a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine
ring, a triazine ring, a quinoline ring or a quinoxaline ring, or a
furan ring, or a thiophene ring, each of which may have a
substituent such as an alkyl group, an aryl group, or a halogen
atom.
[0161] The polyfunctional styrene crosslinking agent is preferably
a compound in which R.sup.21 and R.sup.22 are both hydrogens,
R.sup.23 is a hydrogen atom or a lower-alkyl group having 4 or less
carbon atoms (such as a methyl group or an ethyl group), and m is 2
to 10. In the following, examples ((C-1) to (C-11)) of the
polyfunctional styrene crosslinking agent are shown below, but the
examples should not be construed as limiting the invention.
##STR00030## ##STR00031## ##STR00032##
[0162] In the invention, these monomers may be used in the form of
a prepolymer such as a dimer, a trimer, or an oligomer, in the form
of a mixture thereof, or in the form of a copolymer thereof.
[0163] The polymerizable group to be used is preferably an ester
between an unsaturated carboxylic acid and an aliphatic polyhydric
alcohol compound or an amide between an unsaturated carboxylic acid
and an aliphatic polyamine compound, more preferably an ester
between an unsaturated carboxylic acid and an aliphatic polyhydric
alcohol compound from the viewpoint of developability and printing
durability of the recording layer of the resultant planographic
printing plate precursor.
[0164] In the first embodiment, the amount of the polymerizable
compound to be used is preferably 5 to 90% by mass based on the
total amount of the solids in the polymerizable composition, more
preferably 10 to 80% by mass, still more preferably 20 to 75% by
mass, from the viewpoint of film forming property, printing
durability, and storage stability.
[0165] In the second embodiment, the amount of the polymerizable
compound is preferably 5 to 80% by mass based on the involatile
components in the photopolymerizable layer, more preferably 25 to
75% by mass. Only a single polymerizable compound may be used or
two or more polymerizable compounds may be used. Details of use of
the addition-polymerizable compound may be determined in
consideration of the degree of polymerization inhibition by oxygen,
resolution, fogging, change in refractive index, and surface
adhesiveness. An appropriate structure, an adequate amount to be
added, and an appropriate composition of the polymerizable compound
may be determined in consideration of the above factors. In some
cases, a layer constitution and a coating method such as
undercoating and overcoating may be adopted.
[0166] The details of use of the polymerizable compound may be
determined in accordance with the desired properties of the
resultant planographic printing plate precursor, the details
include the structure of the polymerizable compound, the amount of
the polymerizable compound, and whether only a single polymerizable
compound is used or two or more polymerizable compounds are used.
The details may be determined in consideration of the factors
described below.
[0167] From the viewpoint of sensitivity, the amount of unsaturated
groups per molecule is preferably large, and, in many cases, the
polymerizable compound preferably has two or more unsaturated
groups. In order to heighten the strength of image portions (cured
film), the polymerizable compound preferably has three or more
unsaturated groups. It is preferable to adjust both sensitivity and
strength by using polymerizable compounds each having a different
number of unsaturated groups and/or a different type of
polymerizable group (which may be selected from an acrylic ester, a
methacrylic ester, a styrene compound, or a vinyl ether
compound).
[0168] The selection and use of the addition-polymerizable compound
largely affect the compatibility of the addition-polymerizable
compound with other components (such as a binder polymer, an
initiator, and a colorant) in the photopolymerizable layer or in
the polymerizable composition and dispersibility of the
addition-polymerizable compound in such other components. For
example, the compatibility with other components can be sometimes
improved by use of an addition-polymerizable compound with a low
purity or use of two or more addition-polymerizable compounds. A
specific structure may be selected in order to improve the adhesion
to the support or an overcoat layer described below.
[0169] In the invention, there are several methods for
incorporating components of the photopolymerizable layer described
above and other components into the photopolymerizable layer or for
incorporating components of the polymerizable composition into the
polymerizable composition. A method disclosed in JP-A No.
2002-287334 (the disclosure of which is incorporated herein by
reference) comprises dissolving the components in an appropriate
solvent to form a coating liquid and applying the coating liquid so
as to make a molecular-dispersion-type image-forming layer. Another
method disclosed in JP-A Nos. 2001-277740 and 2001-277742 comprises
encapsulating some of the components or all of the components and
incorporating the microcapsules into the image-recording layer so
as to make a microcapsule-type image-recording layer. In this
method, there may be components which are not contained in the
microcapsules. The microcapsule-type image-recording layer
preferably has such a constitution that hydrophobic components are
contained in microcapsules and hydrophilic components are present
outside the microcapsules. The image-recording layer is preferably
a microcapsule-type image-recording layer from the viewpoint of
obtaining superior on-press developability.
[0170] Known methods can be used for encapsulating components of
the photopolymerizable layer or components of the
photopolymerizable composition. The following methods are examples
of methods for forming microcapsules: methods using coacervation
disclosed in U.S. Pat. Nos. 2,800,457 and 2,800,485 (the
disclosures of which are incorporated herein by reference); methods
involving surface polymerization disclosed in U.S. Pat. No.
3,287,154 and JP-B Nos. 38-19574 and 42-446 (the disclosures of
which are incorporated herein by reference); methods using
precipitation of polymers disclosed in U.S. Pat. Nos. 3,418,250 and
3,660,304; methods using isocyanate polyol wall materials disclosed
in U.S. Pat. No. 3,796,669 (the disclosure of which is incorporated
herein by reference); methods using isocyanate wall materials
disclosed in U.S. Pat. No. 3,914,511 (the disclosure of which is
incorporated herein by reference); methods using a
urea-formaldehyde wall-forming material or a urea
formaldehyde-resorcinol wall forming material disclosed in U.S.
Pat. Nos. 4,001,140, 4,087,376, and 4,089,802 (the disclosures of
which are incorporated herein by reference); methods using wall
materials such as melamine-formaldehyde resins and hydroxycellulose
disclosed in U.S. Pat. No. 4,025,445 (the disclosure of which is
incorporated herein by reference); in situ methods involving
polymerization of monomers disclosed in JP-B Nos. 36-9163 and
51-9079 (the disclosures of which are incorporated herein by
reference); spray-drying methods disclosed in GB No. 930422 and
U.S. Pat. No. 3,111,407 (the disclosures of which are incorporated
herein by reference); and electrolytic dispersion cooling methods
disclosed in GB Patent Nos. 952807 and 967074 (the disclosures of
which are incorporated herein by reference). Methods other than the
above are also usable.
[0171] In the invention, the microcapsule wall is preferably a wall
which has three-dimensional crosslinking and which can be swollen
by a solvent. From such viewpoints, the wall material of the
microcapsule is preferably polyurea, polyurethane, polyester,
polycarbonate, polyamide, or a mixture thereof, more preferably
polyurea or polyurethane. The microcapsule wall may contain a
compound having a crosslinkable functional group such as an
ethylenic unsaturated bond which compound can be introduced to the
binder polymer described above.
[0172] The average particle size of the microcapsule is preferably
0.01 to 3.0 .mu.m, more preferably 0.05 to 2.0 .mu.m, still more
preferably 0.10 to 1.0 .mu.m. When the average particle diameter of
the microcapsule is within the above ranges, the resolution and
storage stability are improved.
Polymerization Initiator
[0173] The polymerizable composition of the first embodiment and
the photopolymerizable layer of the second embodiment preferably
contain a polymerization initiator from the viewpoint of
sensitivity. The polymerization initiator may be selected from
known photopolymerization initiators disclosed in patent documents
and other literatures and combinative systems (photopolymerization
initiation systems) each comprising two or more photopolymerization
initiators.
[0174] The photopolymerization initiator is preferably selected
from: (a) aromatic ketones; (b) aromatic onium salt compounds; (c)
organic peroxides; (d) thio compounds; (e) hexaaryl biimidazole
compounds; (f) ketoxime ester compounds; (g) borate compounds; (h)
azinium compounds; (i) metallocene compounds; (j) active ester
compounds; and (k) compounds having carbon-halogen bond. Specific
examples of (a) to (k) are shown below, but such examples are not
intended to limit the scope of the invention.
(a) Aromatic Ketones
[0175] In the invention, preferred examples of (a) aromatic ketone
as a polymerization initiator include the compounds each having a
benzophenone skeleton or a thioxanthone skeleton disclosed in J. P.
Fouassier and J. F. Rabek, RADIATION CURING IN POLYMER SCIENCE AND
TECHNOLOGY, pp. 77-117, 1993, (the disclosure of which is
incorporated herein by reference), such as the following
compounds:
##STR00033## ##STR00034##
[0176] In particular, preferable examples of (a) aromatic ketones
include:
[0177] .alpha.-thiobenzophenone compounds disclosed in JP-B No.
47-6416 (the disclosure of which is incorporated herein by
reference) and benzoin ether compounds disclosed in JP-B No.
47-3981 (the disclosure of which is incorporated herein by
reference), such as the following compound:
##STR00035##
[0178] .alpha.-substituted benzoin compounds disclosed in JP-B No.
47-22326 (the disclosure of which is incorporated herein by
reference), such as the following compound:
##STR00036##
[0179] benzoin derivatives disclosed in JP-B No. 47-23664 (the
disclosure of which is incorporated herein by reference), aroyl
phosphonate esters disclosed in JP-A No. 57-30704 (the disclosure
of which is incorporated herein by reference) and
dialkoxybenzophenone disclosed in JP-B No. 60-26483 (the disclosure
of which is incorporated herein by reference), such as the
following compound:
##STR00037##
[0180] benzoin ethers disclosed in JP-B No. 60-26403 and JP-A No.
62-81345 (the disclosures of which are incorporated herein by
reference), such as the following compound:
##STR00038##
[0181] .alpha.-aminobenzophenones disclosed in JP-B No. 01-34242,
U.S. Pat. No. 4,318,791 and European Patent No. 0284561 A1 (the
disclosures of which are incorporated herein by reference), such as
the following compounds:
##STR00039##
[0182] p-di(dimethylaminobenzoyl)benzene disclosed in JP-A No.
2-211452 (the disclosure of which is incorporated herein by
reference), such as the following compound:
##STR00040##
[0183] thio-substituted aromatic ketones disclosed in JP-A No.
61-194062 (the disclosure of which is incorporated herein by
reference), such as the following compound:
##STR00041##
[0184] acylphosphine sulfides disclosed in JP-B No. 2-9597 (the
disclosure of which is incorporated herein by reference), such as
the following compounds:
##STR00042##
[0185] acylphosphines disclosed in JP-B No. 2-9596 (the disclosure
of which is incorporated herein by reference), such as the
following compounds:
##STR00043##
[0186] thioxanthones disclosed in JP-B No. 63-61950 (the disclosure
of which is incorporated herein by reference), and coumarins
disclosed in JP-B No. 59-42864 (the disclosure of which is
incorporated herein by reference).
(b) Onium Salt Compounds
[0187] In the invention, preferred examples of (b) onium salt
compound for use as the structure having the ability to initiate
polymerization include the compounds respectively represented by
formulae (1) to (3) below.
##STR00044##
[0188] In formula (1), Ar.sup.1 and Ar.sup.2 each independently
represent an aryl group having 20 or less carbon atoms which may
have a substituent. When the aryl group has a substituent, the
substituent is preferably a halogen atom, a nitro group, an alkyl
group having 12 or less carbon atoms, an alkoxy group having 12 or
less carbon atoms, or an aryloxy group having 12 or less carbon
atoms. (Z.sup.2).sup.- represents a counter ion selected from the
group consisting of halogen ions, a perchlorate ion, carboxylate
ions, a tetrafluoroborate ion, a hexafluorophosphate ion, and
sulfonate ions. (Z.sup.2).sup.- is preferably a perchlorate ion, a
hexafluorophosphate ion, or an arylsulfonate ion.
[0189] In formula (2), Ar.sup.3 represents an aryl group having 20
or less carbon atoms which may have a substituent. The substituent
is preferably a halogen atom, a nitro group, an alkyl group having
12 or less carbon atoms, an alkoxy group having 12 or less carbon
atoms, an aryloxy group having 12 or less carbon atoms, an
alkylamino group having 12 or less carbon atoms, a dialkylamino
group having 12 or less carbon atoms, an arylamino group having 12
or less carbon atoms, or a diarylamino group having 12 or less
carbon atoms. (Z.sup.3).sup.- represents a counter ion whose
definition is the same as that of (Z.sup.2).sup.-.
[0190] In formula (3), R.sup.23, R.sup.24 and R.sup.25 each
independently represent a hydrocarbon group having 20 or less
carbon atoms which may have a substituent. The substituent is
preferably a halogen atom, a nitro group, an alkyl having 12 or
less carbon atoms, an alkoxy group having 12 or less carbon atoms,
or an aryloxy group having 12 or less carbon atoms. (Z.sup.4).sup.-
represents a counter ion whose definition is the same as that of
(Z.sup.2).sup.-.
[0191] Examples of (b) onium salt compounds include the onium salt
compounds disclosed in JP-A No. 2001-133969, paragraphs
[0030]-[0033], JP-A No. 2001-92127, paragraphs [0096]-[0101] and
JP-A No. 2001-343742, paragraphs [0015]-[0046], the disclosures of
which are incorporated by reference herein.
[0192] The onium salt used in the invention preferably has an
absorption peak wavelength of 400 nm or shorter, more preferably
360 nm or shorter. When the absorption peak is in the ultraviolet
region as described above, the planographic printing plate
precursor can be handled under safe light.
(c) Organic Peroxides
[0193] Examples of (c) organic peroxide as a polymerization
initiator include most organic compounds having at least one
oxygen-oxygen bond in the molecule. Specific examples thereof
include methyl ethyl ketone peroxide, cyclohexanone peroxide,
3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone
peroxide, acetylacetone peroxide,
1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane,
1,1-bis(tert-butylperoxy)cyclohexane,
2,2-bis(tert-butylperoxy)butane, tert-butyl hydroperoxide, cumene
hydroperoxide, diisopropylbenzene hydroperoxide, paramethane
hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide,
1,1,3,3-tetramethylbutyl hydroperoxide, di-tert-butyl peroxide,
tert-butylcumyl peroxide, dicumyl peroxide,
bis(tert-butylperoxyisopropyl)benzene,
2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 2,5-hexanoyl peroxide,
succinic peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide,
meta-toluoyl peroxide, diisopropyl peroxydicarbonate,
di-2-ethylhexyl peroxydicarbonate, di-2-ethoxyethyl
peroxydicarbonate, dimethoxyisopropyl peroxycarbonate,
di(3-methyl-3-methoxybutyl)peroxydicarbonate, tert-butyl
peroxyacetate, tert-butyl peroxypivalate, tert-butyl
peroxyneodecanoate, tert-butyl peroxyoctanoate, tert-butyl
peroxy-3,5,5-trimethylhexanoate, tert-butyl peroxylaurate,
tert-carbonate,
3,3',4,4'-tetra(tert-butylperoxycarbonyl)benzophenone,
3,3',4,4'-tetra(tert-amylperoxycarbonyl)benzophenone,
3,3',4,4'-tetra(tert-hexylperoxycarbonyl)benzophenone,
3,3',4,4'-tetra(tert-octylperoxycarbonyl)benzophenone,
3,3',4,4'-tetra(cumylperoxycarbonyl)benzophenone,
3,3',4,4'-tetra(p-isopropylcumylperoxycarbonyl)benzophenone,
carbonyl di(tert-butylperoxy dihydrogen diphthalate), and carbonyl
di(tert-hexylperoxy dihydrogen diphthalate).
[0194] Among them, preferred are peroxide esters such as
3,3',4,4'-tetra(tert-butylperoxycarbonyl)benzophenone,
3,3',4,4'-tetra(tert-amylperoxycarbonyl)benzophenone,
3,3',4,4'-tetra(tert-hexylperoxycarbonyl)benzophenone,
3,3',4,4'-tetra(tert-octylperoxycarbonyl)benzophenone,
3,3',4,4'-tetra(cumylperoxycarbonyl)benzophenone,
3,3',4,4'-tetra(p-isopropylcumylperoxycarbonyl)benzophenone, and
di-tert-butyl diperoxyisophthalate.
(d) Thio Compounds
[0195] In the invention, preferred examples of (d) thio compounds
as polymerization initiators include compounds represented by
Formula (4):
##STR00045##
[0196] In formula (4), R.sup.26 represents an alkyl group, an aryl
group or a substituted aryl groups; R.sup.27 represents a hydrogen
atom or an alkyl groups; or R.sup.26 and R.sup.27 represent such
nonmetallic atomic groups that R.sup.26 and R.sup.27 are bonded to
each other to form a five- to seven-membered ring optionally
containing a hetero atom selected from oxygen atoms, sulfur atoms
and nitrogen atoms.
[0197] In formula (4), when any of R.sup.26 and R.sup.27 represents
an alkyl group, the alkyl group preferably has 1 to 4 carbon atoms.
When any of R.sup.26 and R.sup.27 represents an aryl group, the
aryl group is preferably an aryl group having 6 to 10 carbon atoms,
such as a phenyl group or a naphthyl group. When any of R.sup.26
and R.sup.27 represents a substituted aryl group, the substituted
aryl group may be an aryl group substituted by a halogen atom such
as a chlorine atom, an aryl substituted by an alkyl group such as a
methyl group, or an aryl group substituted by an alkoxy group such
as a methoxy group or an ethoxy group. R.sup.27 is preferably an
alkyl group having 1 to 4 carbon atoms. Examples of the thio
compound represented by formula (4) include the following
compounds:
TABLE-US-00001 TABLE 1 No. R.sup.26 R.sup.27 1 --H --H 2 --H
--CH.sub.3 3 --CH.sub.3 --H 4 --CH.sub.3 --CH.sub.3 5
--C.sub.6H.sub.5 --C.sub.2H.sub.5 6 --C.sub.6H.sub.5
--C.sub.4H.sub.9 7 --C.sub.6H.sub.4Cl --CH.sub.3 8
--C.sub.6H.sub.4Cl --C.sub.4H.sub.9 9 --C.sub.6H.sub.4--CH.sub.3
--C.sub.4H.sub.9 10 --C.sub.6H.sub.4--OCH.sub.3 --CH.sub.3 11
--C.sub.6H.sub.4--OCH.sub.3 --C.sub.2H.sub.5 12
--C.sub.6H.sub.4--OC.sub.2H.sub.5 --CH.sub.3 13
--C.sub.6H.sub.4--OC.sub.2H.sub.5 --C.sub.2H.sub.5 14
--C.sub.6H.sub.4--OCH.sub.3 --C.sub.4H.sub.9 15
--(CH.sub.2).sub.2-- 16 --(CH.sub.2).sub.2--S-- 17
--CH(CH.sub.3)--CH.sub.2--S-- 18 --CH.sub.2--CH(CH.sub.3)--S-- 19
--C(CH.sub.3).sub.2--CH.sub.2--S-- 20
--CH.sub.2--C(CH.sub.3).sub.2--S-- 21 --(CH.sub.2).sub.2--O-- 22
--CH(CH.sub.3)--CH.sub.2--O-- 23 --C(CH.sub.3).sub.2--CH.sub.2--O--
24 --CH.dbd.CH--N(CH.sub.3)-- 25 --(CH.sub.2).sub.3--S-- 26
--(CH.sub.2).sub.2--CH(CH.sub.3)--S-- 27 --(CH.sub.2).sub.3--O-- 28
--(CH.sub.2).sub.5-- 29 --C.sub.6H.sub.4--O-- 30
--N.dbd.C(SCH.sub.3)--S-- 31 --C.sub.6H.sub.4--NH-- 32
##STR00046##
(e) Hexaarylbiimidazole Compounds
[0198] In the invention, examples of (e) hexaarylbiimidazole
compounds as polymerization initiators include lophine dimers
disclosed in JP-B Nos. 45-37377 and 44-86516 (the disclosures of
which are incorporated herein by reference), such as
2,2'-bis(o-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole,
2,2'-bis(o-bromophenyl)-4,4',5,5'-tetraphenylbiimidazole,
2,2'-bis(o,p-dichlorophenyl)-4,4',5,5'-tetraphenylbiimidazole,
2,2'-bis(o-chlorophenyl)-4,4',5,5'-tetra(m-methoxyphenyl)biimidazole,
2,2'-bis(o,o'-dichlorophenyl)-4,4',5,5'-tetraphenylbiimidazole,
2,2'-bis(o-nitrophenyl)-4,4',5,5'-tetraphenylbiimidazole,
2,2'-bis(o-methylphenyl)-4,4',5,5'-tetraphenylbiimidazole, and
2,2'-bis(o-trifluorophenyl)-4,4',5,5'-tetraphenylbiimidazole.
(f) Ketoxime Ester Compounds
[0199] In the invention, examples of (f) ketoxime ester compounds
as polymerization initiators include 3-benzoyloxyiminobutan-2-one,
3-acetoxyiminobutan-2-one, 3-propionyloxyiminobutan-2-one,
2-acetoxyiminopentan-3-one, 2-acetoxyimino-1-phenylpropan-1-one,
2-benzoyloxyimino-1-phenylpropan-1-one,
3-p-toluenesulfonyloxyiminobutan-2-one, and
2-ethoxycarbonyloxyimino-1-phenylpropan-1-one.
(g) Borate Compounds
[0200] In the invention, examples of (g) borate compounds as
polymerization initiators include compounds represented by formula
(5):
##STR00047##
[0201] In formula (5), R.sup.28, R.sup.92, R.sup.30, and R.sup.31
each independently represent a substituted or unsubstituted alkyl
group, a substituted or unsubstituted aryl group, a substituted or
unsubstituted alkenyl group, a substituted or unsubstituted alkynyl
group, or a substituted or unsubstituted heterocyclic group; two or
more of R.sup.28, R.sup.29, R.sup.30, and R.sup.31 may be combined
to form a ring structure; at least one of R.sup.28, R.sup.29,
R.sup.30, and R.sup.31 is a substituted or unsubstituted alkyl
group; and (Z.sup.5).sup.+ represents an alkali metal cation or a
quaternary ammonium cation.
[0202] When any of R.sup.28 to R.sup.31 represents an alkyl group,
the alkyl may be linear, branched or cyclic and has preferably 1 to
18 carbon atoms. Examples thereof include a methyl group, an ethyl
group, a propyl group, an isopropyl group, a butyl group, a pentyl
group, a hexyl group, an octyl group, a stearyl group, a cyclobutyl
group, a cyclopentyl group, and a cyclohexyl group. When any of
R.sup.28 to R.sup.31 represents a substituted alkyl group, the
substituted alkyl group may be an alkyl group obtained by providing
any of the above alkyl groups with a substituent which may be
selected from halogen atoms (such as --Cl and --Br), a cyano group,
a nitro group, aryl groups (preferably a phenyl groups), a hydroxyl
group, --COOR.sup.32 groups (wherein R.sup.32 represents a hydrogen
atom, an alkyl having 1 to 14 carbon atoms or an aryl group),
--OCOR.sup.33 groups (wherein R.sup.33 represents an alkyl group
having 1 to 14 carbon atoms or an aryl group), --OR.sup.34 groups
(wherein R.sup.34 represents an alkyl group having 1 to 14 carbon
atoms or an aryl group), and substituents represented by the
following formula:
##STR00048##
[0203] wherein R.sup.35 and R.sup.36 each independently represent a
hydrogen atom, an alkyl group having 1 to 14 carbon atoms or an
aryl group.
[0204] When any of R.sup.28 to R.sup.31 represents an aryl group,
the aryl group may be an aryl group having 1 to 3 rings such as a
phenyl group and a naphthyl group. When any of R.sup.28 to R.sup.31
represents a substituted aryl group, the substituted aryl group may
be an aryl group obtained by providing such an aryl group as
described above with a substituent which may be selected from: the
substituents cited as examples of the substituent of the
substituted alkyl group, and alkyl groups having 1 to 14 carbon
atoms. The alkenyl group represented by any of R.sup.28 to R.sup.31
may be a linear, branched or cyclic alkenyl group having 2 to 18
carbon atoms. Examples of the substituent in the substituted
alkenyl group represented by any of R.sup.28 to R.sup.31 include
the substituents cited as examples of the substituent in the
substituted alkyl group. The alkynyl represented by any of R.sup.28
to R.sup.31 may be a linear or branched alkynyl group having 2 to
28 carbon atoms. Examples of the substituent in the substituted
alkynyl group represented by any of R.sup.28 to R.sup.31 include
the substituents cited as examples of the substituent in the
substituted alkyl group. The heterocyclic group represented by any
of R.sup.28 to R.sup.31 may be a heterocyclic group having a
heterocycle comprised of five or more atoms including at least one
of N, S and O, preferably a five- to seven-membered heterocyclic
group containing at least one of N, S and O. Such a heterocyclic
group may contain a fused ring and may have any of the
above-described substituents for the substituted aryl group.
Specific examples of the compound represented by formula (5)
include the compounds disclosed in U.S. Pat. Nos. 3,567,453 and
4,343,891 and European Patent Nos. 109,772 and 109,773 (the
disclosures of which are incorporated herein by reference) and the
following compounds:
##STR00049##
[0205] (h) Azinium Compounds
[0206] In the invention, examples of (h) azinium compounds as
polymerization initiators include compounds having N--O bonds
disclosed in JP-A Nos. 63-138345, 63-142345, 63-142346, and
63-143537, and JP-B No. 46-42363, the disclosures of which are
incorporated herein by reference.
(i) Metalocene Compounds
[0207] Examples of the (i) metalocene compounds as polymerization
initiators include titanocene compounds described in JP-A Nos.
59-152396, 61-151197, 63-41484, 2-249 and 2-4705 (the disclosures
of which are incorporated herein by reference), and iron-arene
complexes described in JP-A Nos. 1-304453 and 1-152109 (the
disclosures of which are incorporated herein by reference).
[0208] Specific examples of the titanocene compound include [0209]
di-cyclopentadienyl-Ti-dichloride, [0210]
di-cyclopentadienyl-Ti-bisphenyl, [0211]
di-cyclopentadienyl-Ti-bis-2,3,4,5,6-pentafluorophen-1-yl, [0212]
di-cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, [0213]
di-cyclopentadienyl-Ti-bis-2,4,6-trifluorophen-1-yl, [0214]
di-cyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, [0215]
di-cyclopentadienyl-Ti-bis-2,4-difluorophen-1-yl, [0216]
di-methylcyclopentadienyl-Ti-bis-2,3,4,5,6-pentafluorophen-1-yl,
[0217]
di-methylcyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl,
[0218] di-methylcyclopentadienyl-Ti-bis-2,4-difluorophen-1-yl,
[0219]
bis(cyclopentadienyl)-bis(2,6-difluoro-3-(pyr-1-yl)phenyl)titanium
[0220]
bis(cyclopentadienyl)bis[2,6-difluoro-3-(methylsulfonamide)phenyl]titaniu-
m, [0221]
bis(cyclopentadienyl)bis[2,6-difluoro-3-(N-butylpivaroyl-amino)p-
henyl]titanium, [0222]
bis(cyclopentadienyl)bis[2,6-difluoro-3-(N-butyl-(4-chlorobenzoyl)amino)p-
henyl]titanium, [0223]
bis(cyclopentadienyl)bis[2,6-difluoro-3-(N-benzyl-2,2-dimethylpentanoylam-
ino)phenyl]titanium, [0224]
bis(cyclopentadienyl)bis[2,6-difluoro-3-(N-(2-ethylhexyl)-4-tolyl-sulfony-
l)aminolphenyl]titanium, [0225]
bis(cyclopentadienyl)bis[2,6-difluoro-3-(N-(3-oxaheptyl)-benzoylamino)phe-
nyl]titanium, [0226]
bis(cyclopentadienyl)bis[2,6-difluoro-3-(N-(3,6-dioxadecyl)-benzoylamino)-
phenyl]titanium, [0227]
bis(cyclopentadienyl)bis[2,6-difluoro-3-(trifluoromethylsulfonylamino)phe-
nyl]titanium, [0228]
bis(cyclopentadienyl)bis[2,6-difluoro-3-(trifluoroacetylamino)phenyl]tita-
nium, [0229]
bis(cyclopentadienyl)bis[2,6-difluoro-3-(2-chlorobenzoylamino)phenyl]tita-
nium, [0230]
bis(cyclopentadienyl)bis[2,6-difluoro-3-(4-chlorobenzoylamino)phenyl]tita-
nium, [0231]
bis(cyclopentadienyl)bis[2,6-difluoro-3-(N-(3,6-dioxadecyl)-2,2-dimethylp-
entanoylamino)phenyl]titanium, [0232]
bis(cyclopentadienyl)bis[2,6-difluoro-3-(N-(3,7-dimethyl-7-methoxyoctyl)b-
enzoylamino)phenyl]titanium, and [0233]
bis(cyclopentadienyl)bis[2,6-difluoro-3-(N-cyclohexylbenzoylamino)phenyl]-
titanium.
(j) Active Ester Compounds
[0234] In the invention, examples of (j) active ester compounds as
polymerization initiators include imidosulfonate compounds
disclosed in JP-B No. 62-6223 (the disclosure of which is
incorporated herein by reference) and active sulfonate compounds
disclosed in JP-B No. 63-14340 and JP-A No. 59-174831 (the
disclosures of which are incorporated herein by reference).
(k) Compounds having Carbon-Halogen Bonds
[0235] In the invention, examples of (k) compounds having
carbon-halogen bonds as polymerization initiators include compounds
respectively represented by Formulae (6) to (12) below.
##STR00050##
[0236] In formula (6), X.sup.2 represents a halogen atom; Y.sup.1
represents --C(X.sup.2).sub.3, --NH.sub.2, --NHR.sup.38,
--NR.sup.38, or --OR.sup.38, wherein R.sup.38 represents an alkyl
group, a substituted alkyl group, an aryl group, or a substituted
aryl group; and R.sup.37 represents --C(X.sup.2 ).sub.3, an alkyl
group, a substituted alkyl group, an aryl group, a substituted aryl
group, or a substituted alkenyl group.
##STR00051##
[0237] In formula (7), R.sup.39 represents an alkyl group, a
substituted alkyl group, an alkenyl group, a substituted alkenyl
group, an aryl group, a substituted aryl group, a halogen atom, an
alkoxy group, a substituted alkoxyl group, a nitro group, or a
cyano group; X.sup.3 represents a halogen atom; and n represents an
integer of 1 to 3.
R.sup.40-Z.sup.6-CH.sub.(2-m)(X.sup.3).sub.mR.sup.41 Formula
(8)
[0238] In formula (8), R.sup.40 represents an aryl group or a
substituted aryl group; R.sup.41 represents any of the groups shown
below or a halogen atom; Z.sup.6 represents --C(.dbd.O)--,
--C(.dbd.S)-- or --SO.sub.2--; X.sup.3 represents a halogen atom;
and m represents an integer of 1 or 2.
##STR00052##
[0239] In the formulae, R.sup.42 and R.sup.43 each independently
represent an alkyl group, a substituted alkyl group, an alkenyl
group, a substituted alkenyl group, an aryl group, or a substituted
aryl group; and R.sup.44 has the same definition as that of
R.sup.38 in formula (6).
##STR00053##
[0240] In formula (9), R.sup.45 represents a substituted or
non-substituted aryl or heterocyclic group; R.sup.46 represents a
trihaloalkyl or trihaloalkenyl group having 1 to 3 carbon atoms;
and p represents 1, 2 or 3.
##STR00054##
[0241] The compound represented by formula (10) is a carbonyl
methylene heterocyclic compounds having a trihalogenomethyl group.
In formula (10), L.sup.7 represents a hydrogen atom or
--CO--(R.sup.47)q(C(X.sup.4).sub.3)r; Q.sup.2 represents a sulfur
atom, a selenium atom, an oxygen atom, a dialkylmethylene group, an
alkene-1,2-ylene group, a 1,2-phenylene group, or N--R; M.sup.4
represents a substituted or unsubstituted alkylene or alkenylene
group, or a 1,2-arylene group; R.sup.48 represents an alkyl group,
an aralkyl group or an alkoxyalkyl group; R.sup.47 represents a
carbocyclic or heterocyclic bivalent aromatic group; X.sup.4
represents a chlorine atom, a bromine atom or an iodine atom; q
represents 0 or 1; and r represents 1 when q represents 0 and r
represents 1 or 2 when q represents 1.
##STR00055##
[0242] The compound represented by formula (11) represents a
4-halogeno-5-(halogenomethyl-phenyl)-oxazole derivative. In formula
(11), X.sup.5 represents a halogen atom; t represents an integer of
1 to 3; s represents an integer of 1 to 4; R.sup.49 represents a
hydrogen atom or CH.sub.3-tX.sup.5.sub.t; and R.sup.50 represents a
substituted or non-substituted unsaturated organic group with a
valence of s.
##STR00056##
[0243] The compound represented by formula (12) is a
2-(halogenomethyl-phenyl)-4-halogeno-oxazole derivative. In formula
(12), X.sup.6 represents a halogen atom; v represents an integer of
1 to 3; u represents an integer of 1 to 4; R.sup.51 represents a
hydrogen atom or CH.sub.3-vX.sup.6.sub.v; and R.sup.52 represents a
substituted or non-substituted unsaturated organic group with a
valence of u.
[0244] Specific examples of such compounds having carbon-halogen
bonds include: the compounds disclosed in Wakabayashi et al., Bull.
Chem. Soc. Japan, 42, 2924 (1969) (the disclosure of which is
incorporated herein by reference) such as
2-phenyl-4,6-bis(trichloromethyl)-S-triazine,
2-(p-chlorophenyl)-4,6-bis(trichloromethyl)-S-triazine,
2-(p-tolyl)-4,6-bis(trichloromethyl)-S-triazine,
2-(p-methoxyphenyl)-4,6-bis(trichloromethyl)-S-triazine,
2-(2',4'-dichlorophenyl)-4,6-bis(trichloromethyl)-S-triazine,
2,4,6-tris(trichloromethyl)-S-triazine,
2-methyl-4,6-bis(trichloromethyl)-S-triazine,
2-n-nonyl-4,6-bis(trichloromethyl)-S-triazine, and
2-(.alpha.,.alpha.,.beta.-trichloroethyl)-4,6-bis(trichloromethyl)-S-tria-
zine; the compounds disclosed in U.K. Patent No. 1,388,492 (the
disclosure of which is incorporated herein by reference) such as
2-styryl-4,6-bis(trichloromethyl)-S-triazine,
2-(p-methylstyryl)-4,6-bis(trichloromethyl)-S-triazine,
2-(p-methoxystyryl)-4,6-bis(trichloromethyl)-S-triazine, and
2-(p-methoxystyryl)-4-amino-6-trichloromethyl-S-triazine; the
compounds disclosed in JP-A No. 53-133428 (the disclosure of which
is incorporated herein by reference) such as
2-(4-methoxy-naphtho-1-yl)-4,6-bis-trichloromethyl-S-triazine,
2-(4-ethoxy-naphtho-1-yl)-4,6-bis(trichloromethyl)-S-triazine,
2-[4-(2-ethoxyethyl)-naphtho-1-yl]-4,6-bis(trichloromethyl)-S-triazine,
2-(4,7-dimethoxy-naphtho-1-yl]-4,6-bis-trichloromethyl-S-triazine,
and 2-(acenaphtho-5-yl)-4,6-bis-trichloromethyl-S-triazine; and the
compounds disclosed in German Patent No. 3,337,024 (the disclosure
of which is incorporated herein by reference) such as the following
compounds:
##STR00057##
[0245] Specific examples of compounds having carbon-halogen bonds
also include: the compounds disclosed in F. C. Schaefer et al., J.
Org. Chem., 29, 1527 (1964) (the disclosure of which is
incorporated herein by reference) such as
2-methyl-4,6-bis(tribromomethyl)-S-triazine,
2,4,6-tris(tribromomethyl)-S-triazine,
2,4,6-tris(dibromomethyl)-S-triazine,
2-amino-4-methyl-6-tribromomethyl-S-triazine, and
2-methoxy-4-methyl-6-trichloromethyl-S-triazine; and the compounds
disclosed in JP-A No. 62-58241 (the disclosure of which is
incorporated herein by reference) such as the following
compounds:
##STR00058##
[0246] Specific examples of compounds having carbon-halogen bonds
also include the compounds disclosed in JP-A No. 05-281728 such as
the following compounds:
##STR00059##
[0247] Specific examples of compounds having carbon-halogen bonds
also include compounds shown below, which can be easily synthesized
by one skilled in the art according to the synthesis method
described in M. P. Hutt, E. F Elslager and L. M. Herbel, Journal of
Heterocyclic Chemistry, vol. 7 (No. 3), page 511 et seq. (1970),
the disclosure of which is incorporated herein by reference.
##STR00060##
[0248] Examples of polymerization initiators further include
specific aromatic sulfonium salts disclosed in JP-A Nos.
2001-92127, 2002-148790, and 2002-006482, the disclosures of which
are incorporated herein by reference. The polymerization initiator
is preferably a titanocene compound, an aromatic sulfonium salt, or
a trihalomethyl-S-triazine compound.
[0249] Only a single polymerization initiator may be used, or two
or more polymerization initiators may be used. The amount of
polymerization initiator(s) in the polymerizable composition is
preferably 0.01 to 10% by mass based on the total solids, more
preferably 0.1 to 2% by mass based on the total solids. When the
polymerizable composition is used for a recording layer of a
planographic printing plate precursor, a preferable range of the
amount of polymerization initiator(s) is the same as the range
described above.
[0250] Various photopolymerization initiators (systems) have been
proposed for light sources including blue-ray semiconductor lasers,
Ar lasers, second harmonic wave of IR semiconductor lasers, and
SHG-YAG lasers. Examples thereof include: photo-reductive dyes
disclosed in U.S. Pat. No. 2,850,445, such as rose bengal, eosine,
and erythrosine; and combinations of dyes and initiators such as
complex initiator systems of dyes and amines described in JP-B No.
44-20189, combination systems containing hexaaryl biimidazoles,
radical generators, and dyes disclosed in JP-B No. 45-37377,
systems containing hexaaryl biimidazoles and p-dialkylamino
benzylidene ketone disclosed in JP-B No. 47-2528 and JP-A No.
54-155292, systems containing cyclic cis-.alpha.-dicarbonyl
compounds and dyes disclosed in JP-A No. 48-84183, systems
containing cyclic triazines and melocyanines disclosed in JP-A No.
54-151024, systems containing 3-keto cumarine and activators
disclosed in JP-A Nos. 52-112681 and 58-15503, systems containing
biimidazoles, styrene derivatives and thiols (disclosed in JP-A No.
59-140203), systems containing organic peroxides and dyes disclosed
in JP-A Nos. 59-1504, 59-140203, 59-189340, and 62-174203 and JP-B
No. 62-1641 and U.S. Pat. No. 4,766,055, systems containing dyes
and active halogen compounds disclosed in JP-A No. 63-1718105,
63-258903, and 3-264771, systems containing dyes and borate
compounds disclosed in JP-A Nos. 62-143044, 62-150242, 64-13140,
64-13141, 64-13142, 64-13143, 64-13144, 64-17048, 1-229003,
1-298348, and 1-138204, systems containing colorants having
rhodanine cycles and radical generators disclosed in JP-A Nos.
2-179643 and 2-244050, systems containing titanocenes and 3-keto
cumarine disclosed in JP-A No. 63-221110, systems containing
titanocenes, xantene colorants, and addition-polymerizable
ethylenic unsaturated compounds each having an amino group or an
urethane group disclosed in JP-A Nos. 4-221958 and 4-219756,
systems containing titanocenes and specific melocyanine colorants
disclosed in JP-A No. 6-295061, and systems containing titanocenes
and colorants having benzopyrane cycles disclosed in JP-A No.
8-334897. The disclosures of the above patent documents are
incorporated herein by reference.
[0251] The photopolymerization initiator (system) in the
polymerizable composition or photopolymerizable layer
(photosensitive layer) may contain a titanocene. The titanocene
compound used in the photopolymerization initiator (system) may be
any compound which can generate an active radical when irradiated
with light in the presence of a sensitizing colorant described
later. The titanocene compound may be selected from various
titanocene compounds described in JP-A Nos. 59-152396, 61-151197,
63-41483, 63-41484, 2-249, 2-291, 3-27393, 3-12403 and 6-41170, the
disclosures of which are incorporated herein by reference.
[0252] Specific examples thereof include
di-cyclopentadienyl-Ti-dichloride,
di-cyclopetadienyl-Ti-bis-phenyl,
di-cyclopentadienyl-Ti-bis-2,3,4,5,6-pentafluorophen-1-yl
(hereinafter referred to as "T-1"),
di-cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl,
di-cyclopentadienyl-Ti-bis-2,4,6-trifluorophen-1-yl,
di-cyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl,
di-cyclopentadienyl-Ti-bis-2,4-di-fluorophen-1-yl,
di-methylcyclopentadienyl-Ti-bis-2,3,4,5,6-pentafluorophen-1-yl,
di-methylcyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl,
di-methylcyclopentadienyl-Ti-bis-2,4-difluorophen-1-yl, and
bis(cyclopentadienyl)-bis(2,6-difluoro-3-(pyl-1-yl)phenyl titanium
(hereinafter referred to as "T-2").
[0253] The titanocene compounds may be chemically modified such
that the characteristics of the photosensitive layer is improved.
For example, the chemical modification may be binding of the
titanocene compounds to sensitizing colorants or radical generating
moieties such as addition-polymerizable unsaturated compounds,
introduction of hydrophilic moieties, introduction of substituents
for improving compatibility and/or preventing precipitation of
crystal, introduction of substituents for improving adhesion, and
polymerization of the titanocene compounds.
[0254] Details of the use of the titanocene compounds may be
arbitrary selected in accordance with the desired characteristics
of the resulting planographic printing plate precursor, similarly
to the case of the addition-polymerizable compound described above.
The compatibility with the photosensitive layer may be improved by
using two or more titanocene compounds. The amount of
photopolymerization initiators such as titanocene compounds is
preferably large from the viewpoint of sensitivity. The amount of
photopolymerization initiators may be 0.5 to 80 parts by mass based
on 100 parts by mass of volatile components in the photosensitive
layer, preferably 1 to 50 parts by mass based on 100 parts by mass
of volatile components in the photosensitive layer. When the light
source is a white light source or a yellow light source, the amount
of titanocene compounds to be used is preferably small from the
viewpoint of fogging caused by a light at around 500 nm. However,
when titanocene compound is used in combination with sensitizing
colorants, sufficient sensitivity can be obtained even with an
amount of titanocene compounds of 6 parts by mass or less (which
may be 1.9 parts by mass or less, or 1.4 parts by mass or
less).
[0255] The radical polymerization initiator used for initiating
curing of the addition-polymerizable compound and allowing the
curing to proceed may be a thermal polymerization initiator. The
thermal polymerization initiator may be a thermally-decomposable
radical generator which is decomposed by heat to generate a
radical. When such a radical generator is used in combination with
an IR absorber described later, the IR absorber emits heat upon
irradiation with a IR laser beam and the radical generator
generates a radical, thereby enabling recording.
[0256] The radical generator may be an onium salt, a triazine
compound having a trihalomethyl group, a peroxide, an azo-based
polymerization initiator, an azide compound, a quinone diazide, an
oxime ester compound, or a triarylmonoalkyl borate compound. An
onium salt and an oxime ester compound are preferable because of
their high sensitivity. In the following, an onium salt as
polymerization initiators are described. The onium salt may be an
iodonium salt, a diazonium salt, or a sulfonium salt. In the
invention, these onium salts function not as acid generators but as
initiators for radical polymerization. In the invention, the onium
salt is preferably an onium salt represented by formula (A), (B),
or (C).
##STR00061##
[0257] In the formula (A), Ar.sup.11 and Ar.sup.12 each
independently represent a substituted or non-substituted aryl group
having 20 or less carbon atoms. When the aryl group has a
substituent, the substituent is preferably selected from halogen
atoms, a nitro group, alkyl groups each having 12 or less carbon
atoms, alkoxy groups each having 12 or less carbon atoms, and
aryloxy groups each having 12 or less carbon atoms. Z.sup.11-
represents a counter-ion which may be selected from halogen ions,
perchlorate ions, a tetrafluoroborate ion, a hexafluorophosphate
ion, a carboxylate ion, and sulfonic ions. Z.sup.11- preferably
represents a perchlorate ion, a hexafluorophosphate ion, a
carboxylate ion, or an aryl sulfonic acid ion.
[0258] In the formula (B), Ar.sup.21 represents a substituted or
non-substituted aryl group having 20 or less carbon atoms. When the
aryl group has a substituent, the substituent is preferably
selected from halogen atoms, a nitro group, alkyl groups each
having 12 or less carbon atoms, alkoxy groups each having 12 or
less carbon atoms, aryloxy groups each having 12 or less carbon
atoms, alkylamino groups each having 12 or less carbon atoms,
dialkylamino groups each having 12 or less carbon atoms, aryl amino
groups each having 12 or less carbon atoms, and diaryl amino groups
each having 12 or less carbon atoms. Z.sup.21- represents a
counter-ion having the same definition as that of Z.sup.11-.
[0259] In the formula (C), R.sup.31, R.sup.32 and R.sup.33 each
independently represent a substituted or non-substituted
hydrocarbon group having 20 or less carbon atoms. When the
hydrocarbon group has a substituent, the substituent is preferably
selected from halogen atoms, a nitro group, alkyl groups each
having 12 or less carbon atoms, alkoxy groups each having 12 or
less carbon atoms, and aryloxy groups each having 12 or less carbon
atoms. Z.sup.31- represents a counter-ion having the same
definition as that of Z.sup.11-.
[0260] Onium salts as polymerization initiators (radical
generators) may be selected from the onium salts disclosed in JP-A
No. 2001-133696, the disclosure of which is incorporated herein by
reference. In the following, examples ([OI-1] to [OI-10]) of onium
salts represented by formula (A), examples ([ON-1] to [ON-5]) of
onium salts represented by formula (B), and examples ([OS-1] to
[OS-7]) of onium salts represented by formula (C) are shown below.
However, the examples should not be construed as limiting the
invention.
##STR00062## ##STR00063## ##STR00064## ##STR00065##
[0261] The polymerization initiator used in the invention may have
an absorption peak of 400 nm or shorter, preferably 360 nm or
shorter. When the absorption wavelength is in the UV range, it is
possible to handle the resultant planographic printing plate
precursor under white light.
[0262] The polymerization initiator may also be an aromatic
sulfonium salt selected from the specific aromatic sulfonium salts
disclosed in JP-A Nos. 2002-148790, 2002-350207, and 2003-006552,
the disclosures of which are incorporated herein by reference. In
the following, typical examples thereof are shown.
##STR00066## ##STR00067##
[0263] In the following, an oxime ester compound as a
polymerization initiator is described. The oxime ester compound is
preferably a compound represented by the following formula (D).
##STR00068##
[0264] In formula (D), X represents a carbonyl group, a sulfone
group, or a sulfoxide group; Y represents a cyclic or
straight-chain alkyl, alkenyl, or alkynyl group having 1 to 12
carbon atoms, an aryl group having 6 to 18 carbon atoms, or a
heterocyclic group. The aryl group refers to an aromatic
hydrocarbon compound such as a benzene ring, a naphthalene ring, an
anthracene ring, a phenanthrene group, a pyrene group, or a
triphenylene group. The heterocyclic ring refers to an aromatic
compound whose cycle has at least one atom selected from nitrogen
atoms, sulfur atoms, and oxygen atoms, and examples thereof include
a pyrrole group, a furan group, a thiophene group, a selenophene
group, a pyrazole group, an imidazole group, a triazole group, a
tetrazole group, an oxazole group, a thiazole group, an indole
group, a benzofuran group, a benzimidazole group, a benzoxazole
group, a benzthiazole group, a pyridine group, a pyrimidine group,
a pyrazine group, a triazine group, a quinoline group, a carbazole
group, an acridine group, and compounds such as phenoxazine and
phenothiazine. The substituent represented by Y may be substituted
by: a halogen atom; a hydroxyl group; a nitrile group; a nitro
group; a carboxyl group; an aldehyde group; an alkyl group; a thiol
group; an aryl group; or a compound containing an alkenyl group, an
alkynyl group, an ether group, an ester group, an urea group, an
amino group, an amide group, a sulfide group, a disulfide group, a
sulfoxide group, a sulfo group, a sulfone group, a hydrazine group,
a carboyl group, an imino group, a halogen atom, a hydroxyl group,
a nitrile group, a nitro group, a carboxyl group, a carbonyl group,
an urethane group, an alkyl group, a thiol group, an aryl group, a
phosphoroso group, a phospho groupo, or a carbonyl ether group.
[0265] In formula (D), Z represents a nitrile group, a halogen
atom, a hydrogen atom, an amino group, or a group within the range
of groups that Y in formula (D) can represent. Z in formula (D) may
have a substituent such as: a halogen atom; a hydroxyl group; a
nitrile group; a nitro group; a carboxyl group; an aldehyde group;
an alkyl group; a thiol group; an aryl group; or a compound
containing an alkenyl group, an alkynyl group, an ether group, an
ester group, an urea group, an amino group, an amide group, a
sulfide group, a disulfide group, a sulfoxide group, a sulfo group,
a sulfone group, a hydrazine group, a carboyl group, an imino
group, a halogen atom, a hydroxyl group, a nitrile group, a nitro
group, a carboxyl group, a carbonyl group, an urethane group, an
alkyl group, a thiol group, an aryl group, a phosphoroso group, a
phospho groupo, or a carbonyl ether group.
[0266] In formula (D), W represents a divalent organic group which
may be a methylene group, a carbonyl group, a sulfoxide group, a
sulfone group, or an imino group. The methylene group or the imino
group may be substituted by a compound containing a group such as:
an alkyl group; an ester group; a nitrile group, a carbonyl ether
group, a sulfo group, a sulfo ether group, or an ether group. n
represents an integer of 0 or 1.
[0267] In formula (D), V represents a cyclic or straight-chain
alkyl, alkenyl, or alkynyl group having 1 to 12 carbon atoms, or an
aryl, alkoxy, or aryloxy group having 6 to 18 carbon atoms. The
aryl group may be an aromatic hydrocarbon compound such as a
benzene ring, a naphthalene ring, an anthracene ring, a
phenanthrene group, a pyrene group, or a triphenylene group, or an
aromatic compound containing a hetero-atom such as a pyrrole group,
a furan group, a thiophene group, a selenophene group, a pyrazole
group, an imidazole group, a triazole group, a tetrazole group, an
oxazole group, a thiazole group, an indole group, a benzofuran
group, a benzimidazole group, a benzoxazole group, a benzthiazole
group, a pyridine group, a pyrimidine group, a pyrazine group, a
triazine group, a quinoline group, a carbazole group, an acridine
group, or a compounds such as phenoxazine or phenothiazine.
[0268] The group represented by V may be substituted by: a halogen
atom; a hydroxyl group; a nitrile group; a nitro group; a carboxyl
group; an aldehyde group; an alkyl group; a thol group; an aryl
group; or a compound containing an alkenyl group, an alkynyl group,
an ether group, an ester group, an urea group, an amino group, an
amide group, a sulfide group, a disulfide group, a sulfoxide group,
a sulfo group, a sulfone group, a hydrazine group, a carbonyl
group, an imino group, a halogen atom, a hydroxyl group, a nitrile
group, a nitro group, a carboxyl group, a carbonyl group, an
urethane group, an alkyl group, a thiol group, an aryl group, a
phosphoroso group, a phospho group, or a carbonyl ether group.
[0269] V and Z may be bonded to each other to form a ring.
[0270] In the oxime ester compound represented by formula (D), X is
preferably a carbonyl group, Y is preferably an aryl group or a
benzoyl group, Z is preferably an alkyl group or an aryl group, W
is preferably a carbonyl group, V is preferably an aryl group, from
the viewpoint of sensitivity. V is more preferably an aryl group
having a thioether substituent.
[0271] In formula (D), the structure of the N--O bond may be in the
E-form or in the Z-form.
[0272] The oxime ester compound may be a compound selected from the
compounds described in: Progress in Organic Coatings, 13 (1985) pp.
123-150; J. C. S Perkin II (1979) pp. 1653-1660; Journal of
Photopolymer Science and Technology (1995) pp. 205-232; J. C. S
Perkin II (1979) pp. 156-162; JP-A Nos. 2000-66385 and 2000-80068,
the disclosures of which are incorporated herein by reference.
[0273] Examples of the oxime ester compound are shown below.
However, the examples should not be construed as limiting the
invention.
##STR00069## ##STR00070## ##STR00071## ##STR00072## ##STR00073##
##STR00074## ##STR00075## ##STR00076## ##STR00077## ##STR00078##
##STR00079## ##STR00080## ##STR00081## ##STR00082## ##STR00083##
##STR00084## ##STR00085## ##STR00086## ##STR00087##
[0274] The polymerization initiator may be added such that the
amount of the polymerization initiator in the photopolymerizable
layer is 0.1 to 50% by mass based on the total amount of the solids
in the photopolymerizable layer, preferably 0.5 to 30% by mass
based on the total amount of the solids in the photopolymerizable
layer, more preferably 1 to 20% by mass based on the total amount
of the solids in the photopolymerizable layer, from the viewpoints
of sensitivity and stains developing in non-image portions at
printing. Only a single polymerization initiator may be used or two
or more polymerization initiators may be used. The polymerization
initiator may be included in the same layer as the layer containing
other components, or may be included in a separate layer.
Sensitizing Colorant
[0275] The polymerizable composition of the first embodiment and
the photopolymerizable layer of the second embodiment may include a
sensitizing colorant from the viewpoint of sensitivity. The
sensitizing colorant may have an absorption peak at a wavelength
within the wavelength range of 350 nm to 850 nm. The sensitizing
colorant may be a spectral sensitizing dye, or a dye or pigment
which interacts with a photopolymerization initiator upon
absorption of light from a light source. The sensitizing dye or
pigment may be a polynuclear aromatic compound (such as pyrene,
perylene, or triphenylene), a xanthene (such as fluorescein,
eosine, erythrosine, rhodamine B, or rose Bengal), a cyanine (such
as thiacarbocyanine or oxacarbocyanine), a merocyanine (such as
merocyanine or carbomerocyanine), a thiazine (such as thionine,
methylene blue, or toluidine blue), an acridine (such as acridine
orange, chloroflavine, or acryflavine), a phthalocyanine (such as
phthalocyanine or a metal phthalocyanine), a porphyrin (such as
tetraphenylporphirin or a porphyrin whose center is substituted by
a metal), a chlorofyll (such as chlorophyll, chlorophylline, and a
chlorophyll whose center is substituted by a metal), a metal
complex (such as the compound described below), an anthraquinone
(such as anthraquinone), or a squarium (such as squarium).
##STR00088##
[0276] The sensitizing dye or pigment may be selected from styryl
colorants described in JP-B No. 37-13034 (the disclosure of which
is incorporated herein by reference) and examples thereof include
the following compounds:
##STR00089##
[0277] The sensitizing dye or pigment may be selected from cationic
dyes disclosed in JP-A No. 62-143044, the disclosure of which is
incorporated herein by reference. Examples thereof include the
following compounds.
##STR00090##
[0278] The sensitizing dye or pigment may be selected from
quinoxalinium salts disclosed in JP-B No. 59-24147, the disclosure
of which is incorporated herein by reference. Examples thereof
include the following compounds.
##STR00091##
[0279] The sensitizing dye or pigment may be selected from novel
methylene blue compounds disclosed in JP-A No. 64-33104, the
disclosure of which is incorporated herein by reference. Examples
thereof include the following compounds.
##STR00092##
[0280] The sensitizing dye or pigment may be selected from
anthraquinones disclosed in JP-A No. 64-56767, the disclosure of
which is incorporated herein by reference. Examples thereof include
the following compounds.
##STR00093##
[0281] The sensitizing dye or pigment may be selected from
benzoxanthene dyes disclosed in JP-A No. 2-1714, and acridines
disclosed in JP-A Nos. 2-226148 and 2-226149, the disclosures of
which are incorporated herein by reference. Examples thereof
include the following compounds.
##STR00094##
[0282] The sensitizing dye or pigment may be selected from pyrylium
salts disclosed in JP-B No. 40-28499, the disclosure of which is
incorporated herein by reference. Examples thereof include the
following compounds.
##STR00095##
[0283] The sensitizing dye or pigment may be selected from cyanines
disclosed in JP-B No. 46-42363, the disclosure of which is
incorporated herein by reference. Examples thereof include the
following compounds.
##STR00096##
[0284] The sensitizing dye or pigment may be selected from
benzofuran colorants disclosed in JP-A No. 2-63053, the disclosure
of which is incorporated herein by reference. Examples thereof
include the following compounds.
##STR00097##
[0285] The sensitizing dye or pigment may be selected from
conjugate ketone colorants disclosed in JP-A Nos. 2-85858 and
2-216154, the disclosures of which are incorporated herein by
reference. Examples thereof include the following compounds.
##STR00098##
[0286] The sensitizing dye or pigment may be selected from
colorants disclosed in JP-A No. 57-10605 and azo cinnamylidene
derivatives disclosed in JP-B No. 2-30321, the disclosures of which
are incorporated herein by reference. Examples thereof include the
following compound.
##STR00099##
[0287] The sensitizing dye or pigment may be selected from cyanine
colorants disclosed in JP-A No. 1-287105, the disclosure of which
is incorporated herein by reference. Examples thereof include the
following compounds.
##STR00100##
[0288] The sensitizing dye or pigment may be selected from xanthene
colorants disclosed in JP-A Nos. 62-31844, 62-31848, and 62-143043,
the disclosures of which are incorporated herein by reference.
Examples thereof include the following compounds.
##STR00101##
[0289] The sensitizing dye or pigment may be selected from
aminostyryl ketones disclosed in JP-B No. 59-28325, the disclosure
of which is incorporated herein by reference. Examples thereof
include the following compounds.
##STR00102##
[0290] The sensitizing dye or pigment may be selected from
colorants represented by the following formulae (13) to (15)
disclosed in JP-A No. 2-179643, the disclosure of which is
incorporated herein by reference.
##STR00103##
[0291] In formulae (13) to (15), A.sup.3 represents an oxygen atom,
a sulfur atom, a selenium atom, a tellurium atom, a nitrogen atom
substituted by an alkyl or aryl group, or a carbon atom substituted
by two alkyl groups; Y.sup.2 represents a hydrogen atom, an alkyl
group, a substituted alkyl group, an aryl group, a substituted aryl
group, an aralkyl group, an acyl group or a substituted
alkoxycarbonyl group; and R.sup.53 and R.sup.54 each independently
represent a hydrogen atom, an alkyl group having 1 to 18 carbon
atoms, or a substituted alkyl group having 1 to 18 carbon atoms in
which the substituent is selected from --OR.sup.55,
--(CH.sub.2CH.sub.2O), --R.sup.55, halogen atoms (F, Cl, Br, and
I), and groups represented by the following formulae (wherein
R.sup.55 represents a hydrogen atom or an alkyl group having 1 to
10 carbon atoms; B.sup.1 represents a dialkylamino group, a
hydroxyl group, an acyloxy group, a halogen atom, or a nitro group;
and w represents an integer of 0 to 4).
##STR00104##
[0292] The sensitizing dye or pigment may be selected from
merocyanine colorants represented by the following formula (16)
disclosed in JP-A No. 2-244050, the disclosure of which is
incorporated herein by reference. Examples thereof include the
following compounds.
##STR00105##
[0293] In formula (16), R.sup.56 and R.sup.57 each independently
represent a hydrogen atom, an alkyl group, a substituted alkyl
group, an alkoxycarbonyl group, an aryl group, a substituted aryl
group, or an aralkyl group. A represents an oxygen atom, a sulfur
atom, a selenium atom, a tellurium atom, a nitrogen atom
substituted by an alkyl or aryl group, or a carbon atom substituted
by two alkyl groups. X.sup.7 represents a non-metal atomic group
necessary for forming a nitrogen-containing heterocyclic
five-membered ring. Y.sup.3 represents a substituted phenyl group,
a substituted or non-substituted polynuclear aromatic cycle, or a
substituted or non-substituted aromatic heterocycle. Z.sup.7
represents a hydrogen atom, an alkyl group, a substituted alkyl
group, an aryl group, a substituted aryl group, an aralkyl group,
an alkoxy group, an alkylthio group, an arylthio group, a
substituted amino group, an acyl group, or an alkoxycarbonyl group.
Z.sup.7 and Y.sup.3 may be bonded to each other to form a ring.
Examples of compounds represented by formula (16) include the
following.
##STR00106##
[0294] The sensitizing dye or pigment may be selected from
merocyanine colorants represented by the following formula (17)
disclosed in JP-B No. 59-28326, the disclosure of which is
incorporated herein by reference.
##STR00107##
[0295] In formula (17), R.sup.58 and R.sup.19 each independently
represent a hydrogen atom, an alkyl group, a substituted alkyl
group, an aryl group, a substituted aryl group, or an aralkyl
group. X.sup.8 represents a substituent having a Hammett's .sigma.
value of -0.9 to +0.5.
[0296] The sensitizing dye or pigment may be selected from
merocyanine colorants represented by the following formula (18)
disclosed in JP-A No. 59-89303, the disclosure of which is
incorporated herein by reference.
##STR00108##
[0297] In formula (18), R.sup.60 and R.sup.61 each independently
represent a hydrogen atom, an alkyl group, a substituted alkyl
group, an aryl group, a substituted aryl group, or an aralkyl
group. X.sup.9 represents a substituent having a Hammett's .sigma.
value of -0.9 to +0.5. Y.sup.4 represents a hydrogen atom, an alkyl
group, a substituted alkyl group, an aryl group, a substituted aryl
group, an aralkyl group, an acyl group, or an alkoxycarbonyl group.
Examples of compounds represented by formula (18) include the
following compounds.
##STR00109##
[0298] The sensitizing dye or pigment may be selected from
merocyanine colorants represented by the following formula (19)
disclosed in JP-A No. 6-269047, the disclosure of which is
incorporated herein by reference.
##STR00110##
[0299] In formula (19), R.sup.62, R.sup.63, R.sup.64, R.sup.65,
R.sup.70, R.sup.71, R.sup.72, and R.sup.73 each independently
represent a hydrogen atom, a halogen atom, an alkyl group a
substituted alkyl group an aryl group, a substituted aryl group, a
hydroxyl group, a substituted oxy group, a mercapto group, a
substituted thio group, an amino group, a substituted amino group,
a substituted carbonyl group, a sulfo group, a sulfonato group, a
substituted sulfinyl group, a substituted sulfonyl group, a
phosphono group, a substituted phosphono group, a phosphonato
group, a substituted phosphonato group, a cyano group, or a nitro
group, wherein a bond may be formed between R.sup.62 and R.sup.63,
between R.sup.63 and R.sup.64, between R.sup.64 and R.sup.65,
between R.sup.70 and R.sup.71, between R.sup.71 and R.sup.63, or
between R.sup.63 and R.sup.64, to form an aliphatic ring or an
aromatic ring. R.sup.66 represents a hydrogen atom, an alkyl group,
a substituted alkyl group, an aryl group, or a substituted aryl
group. R.sup.67 represents a substituted or non-substituted
alkenylalkyl group or a substituted or non-substituted alkynylalkyl
group. R.sup.68 and R.sup.69 each independently represent a
hydrogen atom, a halogen atom, an alkyl group, a substituted alkyl
group, an aryl group, a substituted aryl group, or a substituted
carbonyl group. Examples of compounds represented by formula (19)
include the following compounds.
##STR00111##
[0300] The sensitizing dye or pigment may be selected from
benzpyran colorants represented by the following formula (20)
disclosed in JP-A No. 7-164583, the disclosure of which is
incorporated herein by reference.
##STR00112##
[0301] In formula (20), R.sup.74 to R.sup.77 each independently
represent a hydrogen atom, a halogen atom, an alkyl group, an aryl
group, a hydroxyl group, an alkoxy group, or an amino group.
R.sup.74 to R.sup.77 may be bonded to each other to form a ring
comprised of non-metallic atoms including at least one carbon atom.
R.sup.78 represents a hydrogen atom, an alkyl group, an aryl group,
an aromatic heterocyclyl group, a cyano group, an alkoxy group, a
carboxyl group, or an alkenyl group. R.sup.79 represents a hydrogen
atom, an alkyl group, an aryl group, an aromatic heterocyclyl
group, a cyano group, an alkoxy group, a carboxyl group, an alkenyl
group, or -Z.sup.7-R.sup.78, in which Z.sup.7 represents a carbonyl
group, a sulfonyl group, a sulfinyl group, or an arylene dicarbonyl
group. R.sup.78 and R.sup.79 may be bonded to each other to form a
ring comprised of non-metallic atoms. A.sup.5 represents an O atom,
an S atom, an NH group, or an N atom which may have a substituent.
B.sup.2 represents an O atom or .dbd.C(G.sup.7)(G.sup.8). G.sup.7
and G.sup.8 may be the same as each other, or different from each
other. G.sup.7 and G.sup.8 each represent a hydrogen atom, a cyano
group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyl
group, an arylcarbonyl group, an alkylthio group, an arylthio
group, an alkylsulfonyl group, an aryl sulfonyl group, or a
fuluorosulfonyl group. At least one of G.sup.7 and G.sup.8 is
different from a hydrogen atom. G.sup.7 and G.sup.8 may be bonded
to each other to form a ring comprised of non-metallic atoms
including at least one carbon atom.
[0302] The sensitizing dye may be selected from merocyanine
colorants described in JP-B No. 61-9621, and indolenine cyanine
colorants described in JP-A No. 2002-278057, the disclosures of
which are incorporated herein by reference. The amount of the
sensitizing colorant may be 0.1 to 50% by mass, preferably 0.5 to
30% by mass, more preferably 1 to 20% by mass, based on the total
amount of the solids in the polymerizable composition or the
photopolymerizable layer.
[0303] Furthermore, the following infrared absorbers (dyes or
pigments) can be preferably used as sensitizing colorants. Examples
of the dyes include cyanine dyes described in JP-A Nos. 58-125246,
59-84356, 59-202829 and 60-78787 (the disclosures of which are
incorporated herein by reference), cyanine dyes described in GB
Patent No. 434,875 (the disclosure of which is incorporated herein
by reference), and the specific indolenine cyanine colorants
described above.
[0304] Near-infrared absorbing sensitizing agents described in U.S.
Pat. No. 5,156,938 (the disclosure of which is incorporated herein
by reference) are also preferable, and examples of IR absorbers
further include substituted arylbenz(thio)pyrylium salts described
in U.S. Pat. No. 3,881,924 (the disclosure of which is incorporated
herein by reference), trimethinethiapyrylium salts described in
JP-A No. 57-142645 (U.S. Pat. No. 4,327,169, the disclosures of
which are incorporated herein by reference), pyrylium compounds
described in JP-A Nos. 58-181051, 58-220143, 59-41363, 59-84248,
59-84249, 59-146063 and 59-146061 (the disclosures of which are
incorporated herein by reference), cyanine colorants described in
JP-A No. 59-216146 (the disclosure of which is incorporated herein
by reference), pentamethinethiopyrylium salts described in U.S.
Pat. No. 4,283,475 (the disclosure of which is incorporated herein
by reference), and pyrylium compounds described in JP-B Nos.
5-13514 and 5-19702 (the disclosures of which are incorporated
herein by reference) can also be used.
[0305] Examples of IR absorbing colorants further include
near-infrared absorbing dyes shown by the formulae (I) and (II) in
U.S. Pat. No. 4,756,993 (the disclosure of which is incorporated
herein by reference), and phthalocyanine dyes described in EP-A No.
916,513A2 (the disclosure of which is incorporated herein by
reference).
[0306] Examples of IR absorbing colorants further include anionic
infrared absorbers described in JP-A No. 11-338131 (the disclosure
of which is incorporated herein by reference). The anionic infrared
absorbers as used herein refer to colorants whose nuclei contain
anionic structures but do not contain cationic structures, and
which substantially absorb infrared rays. Examples thereof include
(c1) anionic metal complexes, (c2) anionic carbon blacks, (c3)
anionic phthalocyanines and (c4) compounds represented by the
following formula (21). The counter-cation of the anionic infrared
absorber is a monovalent cation such as a proton, or a polyvalent
cation.
[G.sup.9-M.sup.5-G.sup.10].sub.m(X.sup.10).sup.+ Formula (21)
[0307] The anionic metal complex (c1) as used herein refers to a
complex substantially absorbing light whose net charge (including
charges of the ligands and the central metal) is anionic.
[0308] Examples of the anionic carbon black (c2) include carbon
black to which an anionic group is bound such as a sulfonic acid
group, a carboxylic acid group or a phosphonic acid group. In order
to introduce such a group into carbon black, carbon black may be
oxidized with a predetermined acid as described in Carbon Black
Binran, Third Edition (Carbon Black Handbook, Third Edition), p.
12, edited by Society of Carbon Black, Apr. 5, 1995, published by
Society of Carbon Black, the disclosure of which is incorporated
herein by reference.
[0309] The anionic phthalocyanine (c3) as used herein refers to a
compound in which an anionic group selected from the anionic groups
mentioned as substituents in the description of (c2) is bonded to
the phthalocyanine skeleton to form an anion.
[0310] The compound (c4) represented by formula (21) will be
described in detail. In formula (21), G.sup.9 represents an anionic
substituent; G.sup.10 represents a neutral substituent;
(X.sup.10).sup.+ represents a monovalent to m-valent cation such as
a proton, wherein m represents an integer of 1 to 6; and M.sup.5
represents a conjugated chain, which may have a substituent and may
have a cyclic structure. The conjugated chain M.sup.5 can be
represented by the following formula:
##STR00113##
[0311] In the formula, R.sup.80, R.sup.81 and R.sup.82 each
independently represents a hydrogen atom, a halogen atom, a cyano
group, an alkyl group, an aryl group, an alkenyl group, an alkynyl
group, a carbonyl group, a thio group, a sulfonyl group, a sulfinyl
group, an oxy group or an amino group. R.sup.80, R.sup.81 and
R.sup.82 may be bonded to each other to form a cyclic structure,
and n represents an integer of 1 to 8.
[0312] Among the anionic infrared absorbers represented by formula
(21), the following compounds IRA-1 to IRA-5 are preferable.
##STR00114##
[0313] The cationic infrared absorbers IRC-1 to IRC-44 shown below
are also preferable.
##STR00115## ##STR00116## ##STR00117## ##STR00118## ##STR00119##
##STR00120##
[0314] In the foregoing structural formulae, T.sup.- represents a
monovalent counter anion, preferably a halogen anion (such as F,
Cl.sup.-, Br.sup.- or I.sup.-), a Lewis acid anion (such as
BF.sub.4.sup.-, PF.sub.6.sup.-, SbCl.sub.6.sup.- or
ClO.sub.4.sup.-), an alkylsulfonate anion or an arylsulfonate
anion.
[0315] The alkyl group in the alkylsulfonate is a linear, branched
or cyclic alkyl group having 1 to 20 carbon atoms, and specific
examples thereof include a methyl group, an ethyl group, a propyl
group, a butyl group, a pentyl group, a hexyl group, a heptyl
group, an octyl group, a nonyl group, a decyl group, an undecyl
group, a dodecyl group, a tridecyl group, a hexadecyl group, an
octadecyl group, an eicosyl group, an isopropyl group, an isobutyl
group, a sec-butyl group, a tert-butyl group, an isopentyl group, a
neopentyl group, a 1-methylbutyl group, an isohexyl group, a
2-ethylhexyl group, a 2-methylhexyl group, a cyclohexyl group, a
cyclopentyl group and a 2-norbornyl group. Among these, preferable
are a linear alkyl group having 1 to 12 carbon atoms, a branched
alkyl group having 3 to 12 carbon atoms, and a cyclic alkyl group
having 5 to 10 carbon atoms.
[0316] The aryl group in the arylsulfonate is a group containing
one benzene ring, a group containing a condensed ring comprised of
two or three benzene rings, or a group containing a condensed ring
comprised of a benzene ring and a 5-membered unsaturated ring.
Specific examples thereof include a phenyl group, a naphthyl group,
an anthryl group, a phenanthryl group, an indenyl group, an
acenabutenyl group and a fluorenyl group. Among these, a phenyl
group and a naphthyl group are preferable.
[0317] The following non-ionic infrared absorbents IRN-1 to IRN-9
are also preferable.
##STR00121## ##STR00122##
[0318] The anionic infrared absorber is preferably IRA-1, the
cationic infrared absorber is preferably IRC-7, IRC-30, IRC-40 or
IRC-42, the nonionic infrared absorber is preferably IRN-9.
[0319] When the planographic printing plate precursor is subjected
to image formation with a laser light source emitting infrared
light of 760 nm to 1200 nm, it is preferable to incorporate an IR
absorber into the polymerizable composition or the
photopolymerizable layer. The IR absorber has a function of
converting absorbed infrared light to heat. The heat thus generated
decomposes a polymerization initiator (radical generator) to
generate a radical. The IR absorber may be a dye or pigment having
an absorption peak within the wavelength range of 760 nm to 1200
nm.
[0320] The IR absorber may be a dye selected from known dyes
disclosed, for example, in "Senryou Binran" edited by organic
synthesis chemistry association (1970), the disclosure of which is
incorporated herein by reference. The IR absorber may be an azo
dye, a metal complex azo dye, a pyrazolone azo dye, a
naphthoquinone dye, an anthraquinone dye, a phthalocyanine dye, a
carbonium dye, a quinoneimine dye, a methin dye, a cyanine dye, a
squalirium dye, a pyrylium salt, or a metal thiolate complex. The
IR absorbing dye may be selected from: cyanine dyes such as cyanine
dyes disclosed in JP-A Nos. 58-125246, 59-84356, and 60-78787;
methine dyes such as methine dyes disclosed in JP-A Nos. 58-173696,
58-181690, and 58-194595 (the disclosures of which are incorporated
herein by reference); naphthoquinone dyes such as naphthoquinone
dyes disclosed in JP-A Nos. 58-112793, 58-224793, 59-48187,
59-73996, 60-52940, and 60-63744 (the disclosures of which are
incorporated herein by reference); and squalirium dyes such as
squalirium dyes disclosed in JP-A No. 58-112792 (the disclosure of
which is incorporated herein by reference).
[0321] Examples of IR absorbing colorants further include specific
indolenine cyanine colorants shown below which are disclosed in
JP-A No. 2002-278057.
##STR00123##
[0322] The IR absorbing dye may be a cyanine dye, a squalirium dye,
a pyrylium salt, a nickel thiolate complex, or an indolenine
cyanine dye. The IR absorbing dye is preferably a cyanine dye or an
indolenine cyanine dye. Cyanine dyes represented by the following
formula (i) are more preferable.
##STR00124##
[0323] X.sup.1 represents a hydrogen atom, a halogen atom,
--NPh.sub.2, X.sup.2-L.sup.1, or a group shown below.
##STR00125##
[0324] X.sup.1 represents an oxygen atom, a nitrogen atom, or a
sulfur atom. L.sup.1 represents a hydrocarbon group having 1 to 12
carbon atoms, an aromatic ring having a hetero-atom, or a
hydrocarbon group having 1 to 12 carbon atoms and at least one
hetero-atom. The term "hetero-atom" used here refers to N, S, O, a
halogen atom, or Se.
[0325] Xa.sup.- represents a counter anion. R.sup.a represents a
substituent selected from a hydrogen atom, alkyl groups, aryl
groups, substituted amino groups, non-substituted amino groups, and
halogen atoms.
[0326] In formula (i), R.sup.1 and R.sup.2 each independently
represent a hydrocarbon group having 1 to 12 carbon atoms. R.sup.1
and R.sup.2 are each preferably a hydrocarbon group having 2 or
more carbon atoms, from the viewpoint of storage stability of a
coating solution for recording layer. In a preferable structure,
R.sup.1 and R.sup.2 are bound to each other to form a five-membered
or six-membered ring.
[0327] Ar.sup.1 and Ar may be the same as each other or different
from each other. Ar.sup.1 and Ar.sup.2 each represent an aromatic
hydrocarbon group which may have a substituent. The aromatic
hydrocarbon group may be a benzene ring or a naphthalene ring. The
substituent may be a hydrocarbon group having 12 or less carbon
atoms, a halogen atom, or an alkoxy group having 12 or less carbon
atoms. Y.sup.1 and Y.sup.2 may be the same as each other or
different from each other. Y.sup.1 and Y.sup.2 each represent a
sulfur atom or a dialkylmethylene group having 12 or less carbon
atoms. R.sup.3 and R.sup.4 may be the same as each other or
different from each other. R.sup.3 and R.sup.4 each represent a
hydrocarbon group having 20 or less carbon atoms which may have a
substituent. The substituent may be an alkoxy group having 12 or
less carbon atoms, a carboxyl group, or a sulfo group. R.sup.5 to
R.sup.8 each independently represent a hydrogen atom or a
hydrocarbon group having 12 or less carbon atoms, preferably a
hydrogen atom from the viewpoint of availability of raw materials.
Z.sub.a.sup.- represents a counter-anion. Z.sub.a.sup.- is
unnecessary when the cyanine colorant represented by formula (i) is
electrically neutralized by an anionic substituent within the
cyanine colorant molecule. Z.sub.a.sup.- may be a halogen ion, a
perchloric acid ion, a tetrafluoroborate ion, a hexafluorophosphate
ion, or a sulfonic acid ion, preferably a perchloric acid ion, a
hexafluorophosphate ion, or an arylsulfonic acid ion, from the
viewpoint of storage stability of a coating liquid for the
recording layer.
[0328] Examples of cyanine dyes represented by formula (i) include
cyanine dyes disclosed in paragraphs [0017] to [0019] of JP-A No.
2001-133969, the disclosure of which is incorporated herein by
reference. The specific indolenine cyanine colorants described
above which are disclosed in JP-A No. 2002-278057 are also
preferable.
[0329] The IR absorber may be added to the same layer as the layer
containing other components, or may be added to a separate layer.
The IR absorber may be added such that the polymerizable
composition layer or the photopolymerizable layer of the resultant
negative planographic printing plate precursor has an absorbance of
0.3 to 1.2 (preferably 0.4 to 1.1) at the absorption peak in the
wavelength range of 760 nm to 1200 nm when measured by a reflection
measuring method. When the absorbance is in the range, the
polymerization of the polymerizable composition or the
photopolymerizable layer proceeds uniformly with respect to the
direction of the depth of the layer, and the cured film in image
areas has high strength and adhesion to the support.
[0330] The absorbance of the polymerizable composition layer or the
photopolymerizable layer may be adjusted by the amount of IR
absorber to be added to the layer and by the thickness of the
layer. The absorbance may be measured by a usual method. For
example, the absorbance may be measured by: forming a polymerizable
composition layer or a photopolymerizable layer on a reflective
support such as aluminum such that the layer has a predetermined
thickness which corresponds to an adequate dry coating weight as a
planographic printing plate; and then measuring the reflection
density by an optical densitometer. As an alternative, the
absorbance may be measured by a spectrophotometer according to a
reflection method using an integrating sphere.
Pigment
[0331] Examples of the pigment used in the invention include
commercially available pigments and pigments described in Color
Index (C.I.) Handbook, Saishin Ganryo Binran (Newest Pigment
Handbook) (edited by Society of Pigment Technique, Japan (1977)),
Saishin Ganryo Oyo Gijutu (Newest Pigment Application Techniques)
(CMC Press (1986)) and Insatsu Ink Gijutu (Printing Ink Techniques)
(CMC Press (1984)), the disclosures of which are incorporated
herein by reference.
[0332] Examples of the pigment include black pigments, yellow
pigments, orange pigments, brown pigments, red pigments, violet
pigments, blue pigments, green pigments, fluorescent pigments,
metal powder pigments and pigments bound to polymers. Specific
examples thereof include insoluble azo pigments, azo lake pigments,
condensed azo pigments, chelate azo pigments, phthalocyanine
pigments, anthraquinone pigments, perylene pigments, perynone
pigments, thioindigo pigments, quinacridone pigments, dioxazine
pigments, isoindolinone pigments, quinophthalone pigments, dyed
lake pigments, azine pigments, nitroso pigments, nitro pigments,
natural pigments, fluorescent pigments, inorganic pigments and
carbon black. Among these pigments, carbon black is preferable.
[0333] The pigment may be used without a surface treatment or may
be used after being subjected to a surface treatment. Examples of
surface treatments include a method of coating a resin or wax on
the surface, a method of attaching a surfactant, and a method of
binding a reactive substance (such as a silane coupling agent, an
epoxy compound or a polyisocyanate) onto the surface of the
pigment. These surface treatments are described in Kinzoku Sekken
no Seishitu to Oyo (Natures and Applications of Metallic Soap)
(Saiwai Shobo Co., Ltd.), Insatsu Ink Gijutsu (Printing Ink
Techniques) (CMC Press (1984)), and Saishin Ganryo Oyo Gijutsu
(Newest Pigment Application Techniques) (CMC Press (1986)), the
disclosures of which are incorporated herein by reference.
[0334] The particle diameter of the pigment is preferably 0.01
.mu.m to 10 .mu.m, more preferably 0.05 .mu.m to 1 .mu.m, and still
more preferably 0.1 .mu.m to 1 .mu.m, from the viewpoints of
dispersion stability and evenness of the film. When the particle
diameter is in the range, stability of the pigment dispersion in
the polymerizable composition or the photopolymerizable layer
coating liquid and uniformity of the obtained layer are
improved.
[0335] As a method for dispersing the pigment, conventionally known
dispersing techniques utilized in production of inks and toners can
be used. Examples of dispersing machines include an ultrasonic wave
dispersing instrument, a sand mill, an attritor, a pearl mill, a
super mill, a ball mill, an impeller, a disperser, a KD mill, a
colloid mill, a dynatron, a three-roll mill and a pressure kneader.
Details thereof are described in Saishin Ganryo Oyo Gijutsu (Newest
Pigment Application Techniques) (CMC Press (1986)).
[0336] The sensitizing colorant added for accelerating the curing
reaction of the polymerizable composition or the photopolymerizable
layer may be directly added to the composition or the layer
together with other components, or may be added to a separate layer
adjacent to the layer containing other components. The latter
method can provide similar effects as the effects the former method
provides.
[0337] When a planographic printing plate precursor has a negative
image-recording layer which is the polymerizable composition layer
or the photopolymerizable layer, the sensitizing colorant may be
added to the same layer as the image forming layer or to a separate
layer. The optical density of the recording layer may be 0.1 to 3.0
at the absorption peak in the wavelength range of 300 to 1,200 nm.
When the optical density is in the range, high-sensitivity
recording is possible. The optical density is determined by the
amount of the sensitizing colorant and the thickness of the
recording layer, and can be controlled by those factors.
[0338] The optical density of the recording layer can be measured
by an ordinary method. Examples of measuring methods include a
method comprising forming a recording layer on a transparent or
white support such that the thickness of the recording layer is a
predetermined thickness corresponding to an adequate dry coating
weight as a planographic printing plate, and measuring the optical
density by a transmission-type optical densitometer, and a method
comprising forming a recording layer on a reflective support such
as aluminum, and measuring the reflection density.
[0339] The amount of the pigment or dye may be 0.01 to 50% by mass,
preferably 0.1 to 10% by mass, based on the total amount of the
solids in the recording layer. In the case of the dye, the amount
thereof may be 0.5 to 10% by mass based on the total amount of the
solids in the recording layer. In the case of the pigment, the
amount thereof may be 0.1 to 10% by mass based on the total amount
of the solids in the recording layer. When the amount of the dye or
pigment is in the range, the recording layer has high sensitivity
and is uniform and highly durable.
[0340] When the sensitizing colorant is used, the ratio by mol of
the polymerization initiator to the sensitizing dye in the
polymerizable composition or the photopolymerizable layer may be in
the range of 100:0 to 1:99, preferably in the range of 90:10 to
10:90, still more preferably in the range of 80:20 to 20:80.
[0341] The polymerizable composition or the photopolymerizable
layer may include a co-sensitizer which may be selected from known
compounds each having a function of improving sensitivity or
suppressing polymerization inhibition by oxygen.
[0342] The co-sensitizer may be an amine and may be selected, for
example from amine compounds disclosed in M. R. Sanders "Journal of
Polymer Society" vol. 10 (1972), p. 3173, JP-B No. 44-20189, JP-A
Nos. 51-82102, 52-134692, 59-138205, 60-84305, 62-18537, and
64-33104, and Research Disclosure no. 33825, the disclosures of
which are incorporated herein by reference. The amine may be
triethanol amine, ethyl p-dimethylamino benzoate, p-formyldimethyl
aniline, or p-methylthiodimethyl aniline.
[0343] Other examples of the co-sensitizer include thiols and
sulfides, such as thiol compounds disclosed in JP-B No. 55-500806
and JP-A Nos. 53-702 and 5-142772 (the disclosures of which are
incorporated herein by reference) and disulfide compounds disclosed
in JP-A No. 56-75643 (the disclosure of which is incorporated
herein by reference). Specific examples thereof include
2-mercaptobenzothiazol, 2-mercaptobenzoxazol,
2-mercaptobenzimnidazole, 2-mercapto-4(3H)-quinazoline, and
.beta.-mercaptonaphthalene.
[0344] Other examples of the co-sensitizer include: amino acid
compounds (such as N-phenylglycine, N-phenylimino diacetate, and
derivatives thereof); organic metal compounds such as tributyl tin
acetate disclosed in JP-B No. 48-42965 (the disclosure of which is
incorporated herein by reference); hydrogen donors disclosed in
JP-B No. 55-34414 (the disclosure of which is incorporated herein
by reference); sulfur compounds such as trithiane disclosed in JP-A
No. 6-308727 (the disclosure of which is incorporated herein by
reference); phosphorus compounds such as diethyl phosphite
disclosed in JP-A No. 6-250389 (the disclosure of which is
incorporated herein by reference); and Si--H compounds and Ge--H
compounds disclosed in JP-A No. 8-65779 (the disclosure of which is
incorporated herein by reference).
[0345] When the co-sensitizer is used, the amount thereof may be
0.01 to 50 parts by mass, preferably 0.02 to 20 parts by mass, more
preferably 0.05 to 10 parts by mass, based on 1 part by mass of
polymerization initiator.
Other Components
[0346] In addition to the above components, various additives may
be optionally added to the polymerizable composition of the first
embodiment or to the photopolymerizable layer of the second
embodiment. Examples of the additives include laser-light
absorbers, surfactants, coloring agents, print-out agents,
polymerization inhibitors such as thermal polymerization
inhibitors, plasticizers, inorganic particles, and
low-molecular-weight hydrophilic compounds. Such additives may be
added to the polymerizable composition or to the photopolymerizable
layer in the form of molecular dispersion. As an alternative,
additives may be contained in microcapsules together with the
polymerizable compound.
Surfactant
[0347] It is preferable to use a surfactant in the polymerizable
composition or in the photopolymerizable layer for the purpose of
improving on-press developability at initiation of printing and
improving properties of the coating surface. The surfactant may be
a nonionic surfactant, an anionic surfactant, a cationic
surfactant, an amphoteric surfactant, or a fluorine-based
surfactant. Only a single surfactant may be used, or two or more
surfactants may be used.
[0348] The nonionic surfactant is not particularly limited and may
be a known nonionic surfactant. Examples thereof include
polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers,
polyoxyethylene polystyrylphenyl ethers, polyoxyethylene
polyoxypropylene alkyl ethers, glycerine fatty acid partial esters,
sorbitan fatty acid partial esters, pentaerythritol fatty acid
partial esters, propylene glycol mono-fatty-acid esters, sucrose
fatty acid partial esters, polyoxyethylene sorbitan fatty acid
partial esters, polyoxyethylene sorbitol fatty acid partial esters,
polyethylene glycol fatty acid esters, polyglycerin fatty acid
partial esters, polyoxyethylenized castor oils, polyoxyethylene
glycerine fatty acid partial esters, fatty acid diethanol amides,
N,N-bis-2-hydroxyalkylamines, polyoxyethylene alkyl amines,
triethanolamine fatty acid esters, trialkylamine oxides,
polyethylene glycol, and copolymers of polyethylene glycol and
polypropylene glycol.
[0349] The anionic surfactant used in the invention is not
particularly limited, and may be a conventionally known anionic
surfactant. Examples thereof include fatty acid salts, abietates,
hydroxyalkane sulfonic acid salts, alkane sulfonic acid salts,
dialkylsulfosuccinic ester salts, linear alkyl benzene sulfonates,
branched alkyl benzene sulfonates, alkyl naphthalene sulfonates,
alkyl phenoxy polyoxyethylene propyl sulfonic acid salts,
polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl
taurine sodium salt, N-alkyl sulfosuccinic monoamide disodium
salts, petroleum sulfonic acid salts, sulfated tallow oil, sulfuric
ester salts of alkyl esters of fatty acids, alkyl sulfuric ester
salts, polyoxyethylene alkyl ether sulfuric ester salts, fatty acid
monoglyceride sulfuric ester salts, polyoxyethylene alkyl phenyl
ether sulfuric ester salts, polyoxyethylene styryl phenyl ether
sulfuric ester salts, alkyl phosphoric ester salts, polyoxyethylene
alkyl ether phosphoric ester salts, polyoxyethylene alkyl phenyl
ether phosphoric ester salts, partially saponified styrene-maleic
anhydride copolymers, partially saponified olefin-maleic anhydride
copolymers and formalin condensates of naphthalene sulfonic acid
salts.
[0350] The cationic surfactant used in the invention is not
particularly limited, and may be a conventionally known cationic
surfactant. Examples thereof include alkyl amine salts, quaternary
ammonium salts, polyoxyethylene alkyl amine salts and polyethylene
polyamine derivatives.
[0351] The amphoteric surfactant used in the invention is not
particularly limited, and may be a conventionally known amphoteric
surfactant. Examples thereof include carboxy betaines,
aminocarboxylic acids, sulfobetaines, aminosulfates and
imidazolines.
[0352] Examples of the surfactant further includes the surfactants
obtained by replacing the polyoxyethylene in the above surfactants
by another polyoxyalkylene such as a polyoxymethylene, a
polyoxypropylene, or a polyoxybutylene.
[0353] Fluorine-based surfactants containing perfluoroalkyl groups
are further preferable. Examples of the fluorine-based surfactants
include: anionic surfactants such as perfluoroalkyl carboxylic acid
salts, perfluoroalkyl sulfonic acid salts and perfluoroalkyl
phosphoric acid salts; amphoteric surfactants such as
perfluoroalkyl betaine; cationic surfactants such as perfluoroalkyl
trimethyl ammonium salts; and nonionic surfactants such as
perfluoroalkyl amine oxides, perfluoroalkyl ethylene oxide adducts,
oligomers each having a perfluoroalkyl group and a hydrophilic
group, oligomers each having a perfluoroalkyl group and a
lipophilic group, oligomers each having a perfluoroalkyl group, a
hydrophilic group, and a lipophilic group, and urethanes each
having a perfluoroalkyl group and a lipophilic group. The
fluorine-based surfactants described in JP-A Nos. 62-170950,
62-226143, and 60-168144 (the disclosures of which are incorporated
herein by reference) are also preferable.
[0354] Only a single surfactant may be used or two or more
surfactants may be used. The content of the surfactant in the total
solid of the polymerizable composition or photopolymerizable layer
may be 0.001 to 10% by mass, preferably 0.01 to 5% by mass.
Polymerization Inhibitor
[0355] It is preferable to add a small amount of a thermal
polymerization inhibitor to the polymerizable composition or the
photopolymerizable layer in order to inhibit undesired thermal
polymerization of the polymerizable compound in the composition or
layer during the production or storage thereof.
[0356] Preferable examples of the thermal polymerization inhibitor
include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol,
pyrogallol, t-butyl catechol, benzoquinone,
4,4'-thiobis(3-methyl-6-t-butyl phenol), 2,2'-methylene
bis(4-methyl-6-t-butyl phenol), N-nitroso-N-phenyl hydroxylamine
aluminum salt, and N-nitrosophenylhydroxylamine cerium (III)
salt.
[0357] The amount of the thermal polymerization inhibitor to be
added is preferably about 0.01 to about 5% by weight relative to
the total amount of the composition or layer.
[0358] In order to prevent the polymerization inhibition by oxygen,
a higher fatty acid derivative such as behenic acid or behenic
amide may be added such that the higher fatty acid derivative is
present on the surface of the photosensitive layer in a drying
process after coating. The amount of the higher fatty acid
derivative to be added may be about 0.1% by mass to about 10% by
mass, preferably about 0.5% by mass to about 10% by mass, relative
to the amount of the polymerizable composition or the
photopolymerizable layer.
[0359] Further, a dye or a pigment may be added in order to color
the recording layer. By addition of a dye or pigment, the resulting
planographic printing plate precursor becomes easier to check by
visual inspection or by an image density measuring instrument. The
colorant is preferably a pigment since many dyes tend to decrease
the exposure sensitivity of the polymerizable composition or the
photopolymerizable layer. Accordingly, when a dye is used as the
colorant, it is necessary to consider such characteristics. The
colorant may be a pigment such as a phthalocyanine pigment, an azo
pigment, carbon black, or titanium oxide, or a dye such as ethyl
violet, crystal violet, an azo dye, an anthraquinone dye, or a
cyanine dye. The amount of the dye and pigment to be added may be
about 0.5% by mass to about 5% by mass based on the amount of the
polymerizable composition or the photopolymerizable layer.
[0360] For example, dyes having large absorption in the visible
light range can be used as colorants for an image. Specific
examples of the colorants include Oil Yellow #101, Oil Yellow #103,
Oil Pink #312, Oil Green BG, Oil Blue BOS, Oil Blue #603, Oil Black
BY, Oil Black BS, Oil Black T-505 (which are manufactured by Orient
Chemical Industries, Ltd.), Victoria Pure Blue, Crystal Violet
(CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B
(CI145170B), Malachite Green (CI42000), Methylene Blue (CI52015),
and the dyes disclosed in JP-A 62-293247 (the disclosure of which
is incorporated herein by reference). The colorants may be selected
from pigments such as phthalocyanine pigments, azo pigments, carbon
black and titanium oxide.
[0361] The addition of the colorants is preferable since the
addition enables easy differentiation between the image region and
the non-image region after image formation. The amount of the
colorant to be added may be 0.01 to 10% by mass based on the total
solid of the polymerizable composition or the photopolymerizable
layer.
<Print-Out Agent>
[0362] A compound whose color can be changed by an acid or by a
radical may be added to the photopolymerizable composition or the
photopolymerizable layer in order to form a printout image. Such a
compound may be, for example, a colorant such as a diphenyl methane
colorant, a triphenyl methane colorant, a thiazine colorant, an
oxazine colorant, a xanthene colorant, an anthraquinone colorant,
an iminoquinone colorant, an azo colorant, or an azomethine
colorant.
[0363] Specific examples thereof include dyes such as Brilliant
Green, Ethyl Violet, Methyl Green, Crystal Violet, Basic Fuchsin,
Methyl Violet 2B, Quinaldine Red, Rose Bengal, Metanil Yellow,
Thymol Sulfophthalein, Xylenol Blue, Methyl Orange, Paramethyl Red,
Congo Red, Benzopurprin 4B, .alpha.-Naphthyl Red, Nile Blue 2B,
Nile Blue A, Methyl Violet, Malachite Green, Parafuchsin, Victoria
Pure Blue BOH [manufactured by Hodogaya Kagaku Co., Ltd.], Oil Blue
#603 [manufactured by Orient Chemical Industries, Ltd.], Oil Pink
#312 [manufactured by Orient Chemical Industries, Ltd.], Oil Red 5B
[manufactured by Orient Chemical Industries, Ltd.], Oil Scarlet
#308 [manufactured by Orient Chemical Industries, Ltd.], Oil Red OG
[manufactured by Orient Chemical Industries, Ltd.], Oil Red RR
[manufactured by Orient Chemical Industries, Ltd.], Oil Green #502
[manufactured by Orient Chemical Industries, Ltd.], Spirone Red BEH
Special [manufactured by Hodogaya Kagaku Co., Ltd.], m-Cresol
Purple, Cresol Red, Rhodamine B, Rhodamine 6G, Sulforhodamine B,
Auramine, 4-p-diethylaminophenyl iminonaphthoquinone,
2-carboxyanilino-4-p-diethylaminophenyl iminonaphthoquinone,
2-carboxystearylamino-4-p-N,N-bis(hydroxyethyl)amino-phenyliminonaphthoqu-
inone, 1-phenyl-3-methyl-4-p-diethylaminophenylimino-5-pyrazolone
and 1-.beta.-naphthyl-4-p-diethylaminophenylimino-5-pyrazolone, and
leuco dyes such as p,p',p''-hexamethyl triaminophenyl methane
(Leuco Crystal Violet) and Pergascript Blue SRB (manufactured by
Ciba-Geigy).
[0364] In addition to the printout agents described above,
preferable examples of the printout agent further include leuco
dyes known as materials for thermal sensitive paper and pressure
sensitive paper. Specific examples thereof include crystal violet
lactone, malachite green lactone, benzoyl leucomethylene blue,
2-(N-phenyl-N-methylamino)-6-(N-p-tolyl-N-ethyl)amino-fluoran,
2-anilino-3-methyl-6-(N-ethyl-p-toluidino)fluoran, 3,6-dimethoxy
fluoran,
3-(N,N-diethylamino)-5-methyl-7-(N,N-dibenzylamino)-fluoran,
3-(N-cyclohexyl-N-methylamino)-6-methyl-7-anilinofluoran,
3-(N,N-diethylamino)-6-methyl-7-anilinofluoran,
3-(N,N-diethylamino)-6-methyl-7-xylidinofluoran,
3-(N,N-diethylamino)-6-methyl-7-chlorofluoran,
3-(N,N-diethylamino)-6-methoxy-7-aminofluoran,
3-(N,N-diethylamino)-7-(4-chloroanilino)fluoran,
3-(N,N-diethylamino)-7-chlorofluoran, 3-(N,N-diethylamino)-7-benzyl
aminofluoran, 3-(N,N-diethylamino)-7,8-benzofluoran,
3-(N,N-dibutylamino)-6-methyl-7-anilinofluoran,
3-(N,N-dibutylamino)-6-methyl-7-xylidinofluoran,
3-piperidino-6-methyl-7-anilinofluoran,
3-pyrrolidino-6-methyl-7-anilinofluoran,
3,3-bis(1-ethyl-2-methylindol-3-yl)phthalide,
3,3-bis(1-n-butyl-2-methylindol-3-yl) phthalide,
3,3-bis(p-dimethylaminophenyl)-6-dimethyl amino phthalide,
3-(4-diethylamino-2-ethoxyphenyl)-3-(1-ethyl-2-methylindol-3-yl)-4-phthal-
ide, and
3-(4-diethylaminophenyl)-3-(1-ethyl-2-methylindol-3-yl)phthalide.
[0365] The amount of the dye whose color is changed by an acid or
by a radical is 0.01% by mass to 10% by mass based on the total
amount of the solids in the polymerizable composition or
photopolymerizable layer.
[0366] In addition to the above additives, known additives may be
added such as inorganic fillers and plasticizers for improving the
characteristics of the cured film and sensitizing agents for
improving ink adhesion to the surface of the photosensitive
layer.
<Plasticizer>
[0367] In the invention, a plasticizer may be included in the
polymerizable composition or in the photopolymerizable layer in
order to improve on-press developability.
[0368] Preferable examples of the plasticizer include: phthalic
esters such as dimethyl phthalate, diethyl phthalate, dibutyl
phthalate, diisobutyl phthalate, dioctyl phthalate, octyl capryl
phthalate, dicyclohexyl phthalate, didodecyl phthalate, ditridecyl
phthalate, butyl benzyl phthalate, diisodecyl phthalate and diallyl
phthalate; glycol esters such as dimethyl glycol phthalate, ethyl
phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, butyl
phthalyl butyl glycolate and triethylene glycol dicaprylate ester;
phosphoric esters such as tricresyl phosphate and triphenyl
phosphate; aliphatic dibasic acid esters such as diisobutyl
adipate, dioctyl adipate, dimethyl sebacate, dibutyl sebacate,
dioctyl azelate and dibutyl maleate; and polyglycidyl methacrylate,
triethyl citrate, glycerin triacetyl ester and butyl laurate.
[0369] The content of the plasticizer may be about 30% by mass or
less based on the total amount of the solids of the polymerizable
composition or the photopolymerizable layer. When a binder is used,
the amount of the plasticizer may be 10% by mass or smaller based
on the total amount of the binder and compounds having ethylenic
unsaturate double bonds.
<Inorganic Particles>
[0370] In the invention, the polymerizable composition or the
photopolymerizable layer may further include inorganic particles in
order to improve the strength of the cured film in image areas and
to improve the on-press developability of non-image areas.
[0371] Examples of the inorganic particles include, for example,
silica, alumina, magnesium oxide, titanium oxide, magnesium
carbonate, calcium alginate and mixtures thereof. Even if inorganic
particles cannot convert light to heat, the inorganic particles may
be used for reinforcing the coating film and improving the
interfacial adhesiveness by surface roughening.
[0372] The average particle diameter of the inorganic particles is
preferably 5 nm to 10 .mu.m, more preferably 0.5 .mu.m to 3 .mu.m.
When the average particle diameter is in the range, the inorganic
particles can be dispersed stably in the polymerizable composition
or in the photopolymerizable layer, whereby excellent film strength
of the polymerizable composition layer or the photopolymerizable
layer is obtained and a highly hydrophilic non-image areas which
are hardly blemished during printing are obtained.
[0373] The inorganic particles such as described above are easily
available as commercially available products such as colloidal
silica dispersions.
[0374] The content of the inorganic particles is preferably 40% by
mass or lower, more preferably 30% by mass or lower, based on the
total amount of the solids of the polymerizable composition or the
photopolymerizable layer.
<Low-Molecular-Weight Hydrophilic Compound>
[0375] In the invention, the polymerizable composition or the
photopolymerizable layer may further include a hydrophilic
low-molecular-weight compound in order to improve on-press
developability. The hydrophilic low-molecular-weight compound may
be a water-soluble organic compound. Examples thereof include:
glycols such as ethylene glycol, diethylene glycol, triethylene
glycol, propylene glycol, dipropylene glycol and tripropylene
glycol, and ether derivatives thereof and ester derivatives
thereof; polyhydroxy compounds such as glycerin and
pentaerythritol; organic amines such as triethanol amine, diethanol
amine, and monoethanol amine, and salts thereof; organic sulfonic
acids such as toluene sulfonic acid and benzene sulfonic acid, and
salts thereof; organic phosphonic acids such as phenyl phosphonic
acid, and salts thereof; and organic carboxylic acids such as
tartaric acid, oxalic acid, citric acid, malic acid, lactic acid,
gluconic acid and amino acids, and salts thereof.
[0376] Further, other additives such as UV initiators and thermal
crosslinking agents may also be used for the purpose of enhancing
the effects of post-development heating/exposure treatment
described later which aims at improving the film strength (printing
durability) of the planographic printing plate precursor.
[0377] The polymerizable composition of the invention may be used
in a planographic printing plate precursor described below. In
addition, the polymerizable composition may be used for highly
sensitive photomoldable materials, for hologram materials utilizing
change in refractive index upon polymerization, and for production
of electronic materials such as photoresists.
<Formation of Polymerizable Composition Layer and
Photopolymerizable Layer>
[0378] In the invention, the polymerizable composition layer and
the photopolymerizable layer can be each formed by dispersing or
dissolving the necessary components described above in a solvent to
prepare a coating liquid and then applying the coating liquid.
Examples of the solvent include, but are not limited to: ethylene
dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol,
propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol,
2-methoxyethyl acetate, 1-methoxy-2-propyl acetate,
dimethoxyethane, methyl lactate, ethyl lactate,
N,N-dimethylacetamide, N,N-dimethylformamide, tetramethyl urea,
N-methyl pyrrolidone, dimethyl sulfoxide, sulfolane,
.gamma.-butyrolactone, toluene and water. Only a single solvent may
be used or a mixture of two or more solvents may be used. The total
solid content of the coating liquid is preferably 1 to 50% by
weight. It is possible to form the polymerizable composition layer
or the photopolymerizable layer by: preparing coating liquids each
including different or overlapping components dissolved or
dispersed in a same type of solvent or in different solvents, then
repeating coating and drying to form the layer.
[0379] The amount (in terms of the solid amount) of the
polymerizable composition layer or photopolymerizable layer, which
was formed on the support by coating and drying, may be changed in
accordance with the intended use, and is preferably 0.3 to 3.0
g/m.sup.2 in general. When the amount is in this range, an image
recording layer with high sensitivity and excellent film properties
can be obtained.
[0380] The coating may be conducted by any of various methods whose
examples include bar coating, spin coating, spray coating, curtain
coating, dip coating, air knife coating, blade coating and roll
coating.
[0381] The planographic printing plate precursor of the invention
may include a copolymer (hereinafter occasinally referred to as
"specific copolymer") comprising a repeating unit (a1) having an
ethylenic unsaturated bond and a repeating unit (a2) having a
functional group which can interact with the support surface, in
the polymerizable composition layer or the photopolymerizable
layer. The specific copolymer preferably has a hydrophilic
moiety.
[0382] The specific copolymer is preferably a copolymer comprising
a repeating unit represented by the following formula (I).
##STR00126##
[0383] In formula (I), A.sub.1 represents a repeating unit having
an ethylenic unsaturated bond and A.sub.2 represents a repeating
unit having a functional group capable of interacting with the
support surface. x and y represent copolymerization ratios.
[0384] In formula (I), the repeating unit represented by A.sub.1 is
preferably a repeating unit represented by the following formula
(A1).
##STR00127##
[0385] In formula (A1), R.sub.1 to R.sub.3 each independently
represent a hydrogen atom, an alkyl group having 1 to 6 carbon
atoms, or a halogen atom. R.sub.4 to R.sub.6 each independently
represent a hydrogen atom, an alkyl group having 1 to 6 carbon
atoms, a halogen atom, an acyl group, or an acyloxy group. R.sub.4
and R.sub.5 may be bonded to each other to form a ring, and R.sub.5
and R.sub.6 may be bonded to each other to form a ring. L
represents a divalent connecting group selected from the group
consisting of --CO--, --O--, --NH--, a divalent aliphatic group, a
divalent aromatic group, or a combination thereof.
[0386] When L represents a combination of divalent connecting
groups, examples thereof include the following examples. In the
examples, the left end is bound to the main chain and the right end
is bound to an ethylenic unsaturated bond.
[0387] L1: --CO--NH-divalent aliphatic group-O--CO--
[0388] L2: --CO-divalent aliphatic group-O--CO--
[0389] L3: --CO--O-divalent aliphatic group-O--CO--
[0390] L4: -divalent aliphatic group-O--CO--
[0391] L5: --CO--NH-divalent aromatic group-O--CO--
[0392] L6: --CO-divalent aromatic group-O--CO--
[0393] L7: -divalent aromatic group-O--CO--
[0394] L8: --CO-divalent aliphatic group-CO--O-divalent aliphatic
group-O--CO--
[0395] L9: --CO-divalent aliphatic group-O--CO-divalent aliphatic
group-O--CO--
[0396] L10: --CO-divalent aromatic group-CO--O-divalent aliphatic
group-O--CO--
[0397] L11: --CO-divalent aromatic group-O--CO-divalent aliphatic
group-O--CO--
[0398] L12: --CO-divalent aliphatic group-CO--O-divalent aromatic
group-O--CO--
[0399] L13: --CO-divalent aliphatic group-O--CO-divalent aromatic
group-O--CO--
[0400] L14: --CO-divalent aromatic group-CO--O-divalent aromatic
group-O--CO--
[0401] L15: --CO-divalent aromatic group-O--CO-divalent aromatic
group-O--CO--
[0402] The term "divalent aliphatic group" used in the above
examples refers to an alkylene group, a substituted alkylene group,
an alkenylene group, a substituted alkenylene group, an alkynylene
group, a substituted alkynylene group, or a polyalkyleneoxy group.
The divalent aliphatic group is preferably an alkylene group, a
substituted alkylene group, an alkenylene group, or a substituted
alkenylene group, more preferably an alkylene group or a
substituted alkylene group.
[0403] The divalent aliphatic group preferably has a chain
structure rather than a cyclic structure, and is preferably linear
rather than branched. The divalent aliphatic group preferably has 1
to 20 carbon atoms, more preferably 1 to 15 carbon atoms, still
more preferably 1 to 12 carbon atoms, further more preferably 1 to
10 carbon atoms, most preferably 1 to 8 carbon atoms.
[0404] Examples of substituents on the divalent aliphatic group
include halogen atoms (F, Cl, Br, and I), hydroxyl groups, carboxyl
groups, amino groups, cyano groups, aryl groups, alkoxy groups,
aryloxy groups, acyl groups, alkoxycarbonyl groups, aryloxycarbonyl
groups, acyloxy groups, monoalkylamino groups, dialkylamino groups,
arylamino groups, and diarylamino groups.
[0405] The term "divalent aromatic group" used in the above
examples refers to an aryl group or a substituted aryl group. The
divalent aromatic group is preferably a phenylene group, a
substituted phenylene group, a naphthylene group, or a substituted
naphthylene group. Examples of substituents on the divalent
aromatic group include the substituents cited as examples of the
substituents on the divalent aliphatic group, and alkyl groups.
[0406] In formula (I), the repeating unit represented by A.sub.2
may be a repeating unit represented by the following formula
(A2).
##STR00128##
[0407] In formula (A2), the definitions of R.sub.1 to R.sub.3 and L
are the same as in formula (A1). Q represents a functional group
(hereinafter occasionally referred to as "specific functional
group" capable of interacting with the support surface. The
specific functional group may be a group which can interact with
Si--OH, Si--O.sup.-, Al.sup.3+, aluminum oxide, zirconium oxide, or
the like present on the support surface. The interaction may be an
ionic bond, a hydrogen bond, a polar interaction, or a van der
Waals interaction. Examples of the specific functional group are
shown below.
##STR00129##
[0408] In the formulae, R.sub.11 to R.sub.13 each independently
represent a hydrogen atom, an alkyl group, an aryl group, an
alkynyl group, or an alkenyl group; M.sub.1 and M.sub.2 each
independently represent a hydrogen atom, a metal atom, or an
ammonium group; and X.sup.- represents a counter-anion.
[0409] Among these examples, the specific functional group is
preferably an onium salt group such as an ammonium group or a
pyridinium group, a phosphoric ester group, a phosphonic acid
group, a boric acid group, or a .beta.-diketone group such as an
acetylacetone group.
[0410] In formula (A2), L represents a divalent connecting group
selected from the group consisting of --CO--, --O--, --NH--, a
divalent aliphatic group, a divalent aromatic group, and a
combination thereof.
[0411] When L represents a combination of divalent connecting
groups, examples thereof include the above-described examples of L
in formula (A1) and the following combinations. In the following
exemplary combinations, the left end is bound to the main chain and
the right end is bound to an ethylenic unsaturated bond. [0412]
L16: --CO--NH-- [0413] L17: --CO--O-- [0414] L18: -divalent
aromatic group-
[0415] In the repeating unit represented by formula (A2), there may
be a hydrophilic portion. When the repeating unit represented by
(A2) does not contain a hydrophilic portion, the specific copolymer
preferably further includes a repeating unit represented by the
following formula (A3).
##STR00130##
[0416] In formula (A3), the definitions of R.sub.1 to R.sub.3 and L
are the same as in formula (A1). W represents any of the following
groups.
##STR00131##
[0417] In the formulae, the definition of M.sub.1 is the same as in
formula (A2). R.sub.7 and R.sub.8 each independently represent a
hydrogen atom or a linear or branched alkyl group having 1 to 6
carbon atoms. R.sub.9 represents a linear or branched alkylene
group having 1 to 6 carbon atoms. R.sub.10 represents a hydrogen
atom or an alkyl group having 1 to 12 carbon atoms. n represents an
integer of 1 to 100.
[0418] The molecular weight of the specific copolymer is preferably
500 to 100,000, more preferably 700 to 50,000 in terms of
weight-average molecular weight. The proportion of the repeating
unit (al) to all the monomers in the specific copolymer is
preferably 5 to 80% by mol, more preferably 10 to 50% by mol. The
proportion of the repeating unit (a2) to all the monomers in the
specific copolymer is preferably 5 to 80% by mol, more preferably
10 to 50% by mol. The proportion of the repeating unit (a3) to all
the monomers in the specific copolymer is preferably 5 to 80% by
mol, more preferably 10 to 50% by mol.
[0419] Preferable structures of the specific copolymer in the
invention are shown below, but the structures should not be
construed as limiting the invention.
##STR00132## ##STR00133## ##STR00134## ##STR00135## ##STR00136##
##STR00137## ##STR00138## ##STR00139## ##STR00140## ##STR00141##
##STR00142## ##STR00143## ##STR00144## ##STR00145##
##STR00146##
[0420] In the invention, the specific copolymer may be contained in
the recording layer, or may be contained in a layer adjacent to the
recording layer such as an undercoat layer (intermediate layer)
provided between the support and the recording layer. It is
preferable to use the specific copolymer in the undercoat layer
from the viewpoint of obtaining the effects of the invention. Since
the undercoat layer works as a thermal insulating layer, heat
generated upon exposure to infrared laser light does not
transmitted to the support but is efficiently used for image
recording, thus improving sensitivity. Further, the undercoat layer
makes it easier to peel the recording layer from the support in
unexposed areas, thus improving on-press developability.
[0421] When the specific copolymer is used in the undercoat layer,
the specific copolymer may be added after being dissolved in a
solvent. The solvent may be water or an organic solvent such as
methanol, ethanol, propanol, isopropanol, ethylene glycol, hexylene
glycol, THF, DMF, 1-methoxy-2-propanol, dimethyl acetamide, or
dimethyl sulfoxide. The solvent is preferably an alcohol. The
solvent may be a mixture of solvents.
[0422] The concentration of a coating liquid for undercoat layer is
preferably 0.001 to 10% by mass, more preferably 0.01 to 5% by
mass, still more preferably 0.05 to 1% by mass. The undercoat layer
may optionally include a surfactant in accordance with the
necessity.
[0423] The coating weight of the undercoat layer (in terms of solid
amount) is preferably 0.1 to 100 mg/m.sup.2, more preferably 3 to
30 mg/m.sup.2.
Planographic Printing Plate Precursor
[0424] The polymerizable composition and the photopolymerizable
layer of the invention can be used as a negative recording layer of
a planographic printing plate precursor. In the following, the
planographic printing plate precursor is described. The
planographic printing plate precursor has a constitution in which
the photopolymerizable layer or a recording layer containing the
polymerizable composition is provided on a support. The
planographic printing plate precursor may further comprise other
optional layers.
Recording Layer
[0425] In the first embodiment, the recording layer (photosensitive
layer) of the planographic printing plate precursor is a
polymerizable photosensitive layer which comprises the
polymerizable composition including the specific polymer (A), a
polymerizable compound (an addition-polymerizable compound), and a
polymerization initiator as essential components. The
photopolymerizable layer of the second embodiment is as described
above.
[0426] When exposed to a laser light, the polymerization initiator
in the polymerizable photosensitive layer decomposes to generate a
radical, and the radical causes polymerization of the polymerizable
compound. The planographic printing plate precursor is suitable for
direct printing-plate-making by irradiation with a laser light
having a wavelength of 300 to 1,200 nm. The printing plate
precursor is particularly suitable for recording by semiconductor
lasers such as ultraviolet LD and infrared LD as exposure light
sources, as described above. The planographic printing plate
precursor has high printing durability, image-forming property, and
on-press developability when compared to conventional printing
plate precursors.
[0427] In the planographic printing plate precursor, it is possible
to provide an intermediate layer between the recording layer and
the support so as to improve the adhesion of the recording layer to
the support and so as to improve removability of the recording
layer in unexposed areas at development.
[0428] The recording layer may include a compound capable of
interacting with the support. Such a compound may be a compound
having a diazonium structure, or a phosphon compound. The compound
may be added to the recording layer or to the coating composition
for an undercoat layer. The addition of the compound improves
adhesion and printing durability.
[0429] The removability of non-image areas can be improved by
addition of a hydrophilic polymer such as polyacrylic acid or
polysulfonic acid or by formation of an undercoat layer containing
such a hydrophilic polymer. As a result, the developability of
non-image areas is improved and blemish in the non-image areas can
be prevented effectively.
[0430] When a recording layer is formed by coating a support with
the polymerizable composition of the invention, or when the
photopolymerizable layer of the invention is formed on a support,
components of the polymerizable composition or components of the
photopolymerizable layer may be dissolved in an organic
solvent.
[0431] The organic solvent may be selected from: acetone, methyl
ethyl ketone, cyclohexane, ethyl acetate, ethylene dichloride,
tetrahydrofuran, toluene, ethylene glycol monomethyl ether,
ethylene glycol monoethyl ether, ethylene glycol dimethyl ether,
propylene glycol monomethyl ether, propylene glycol monoethyl
ether, acetyl acetone, cyclohexanone, diacetone alcohol,
ethyleneglycol monomethyl ether acetate, ethyleneglycol ethyl ether
acetate, ethyleneglycol monoisopropyl ether, ethyleneglycol
monobutyl ether acetate, 3-methoxypropanol, methoxymethoxyethanol,
diethyleneglycol monomethyl ether, diethyleneglycol monoethyl
ether, diethyleneglycol dimethyl ether, diethyleneglycol diethyl
ether, propyleneglycol monomethyl ether acetate, propyleneglycol
monoethyl ether acetate, 3-methoxypropyl acetate,
N,N-dimethylformamide, dimethylsulfoxide, .gamma.-butyrolactone,
methyl lactate, and ethyl lactate. Only a single solvent may be
used or a mixture of two or more solvents may be used. The solid
content of the coating liquid may be 2 to 50% by mass.
[0432] The coating weight of the recording layer affects
sensitivity and developability of the recording layer and strength
and printing durability of the exposed film; therefore, the coating
weight may be selected in accordance with the intended use. When
the coating weight is too small, the printing durability tends to
be low. When the coating weight is too large, the sensitivity tends
to be low, exposure takes longer time, and development also takes
longer time.
[0433] When the planographic printing plate precursor is used for
scan-exposure, the dry coating weight of the recording layer may be
about 0.1 g/m.sup.2 to about 10 g/m.sup.2, preferably 0.5 g/m.sup.2
to 5 g/m.sup.2.
<Support>
[0434] The support used in the planographic printing plate
precursor is not particularly limited and may be selected from
known supports for planograpic printing plates. The support may be
hydrophilic.
[0435] The support is preferably a dimensionally stable plate.
Examples thereof include paper, a plastic laminated paper (such as
a polyethylene laminated paper, a polypropylene laminated paper, or
a polystyrene laminated paper), a metal plate (such as an aluminum
plate, a zinc plate, or a copper plate), a plastic film (such as a
cellulose diacetate film, a cellulose triacetate film, a cellulose
propionate film, a cellulose butyrate film, a cellulose acetate
butyrate film, a cellulose nitrate film, a polyethylene
terephthalate film, a polyethylene film, a polystyrene film, a
polypropylene film, a polycarbonate film, or a polyvinyl acetal
film), a paper on which a metal such as described above is
laminated or vapor-deposited, and a plastic film on which a metal
such as described above is laminated or vapor-deposited. The
surface of the support may be subjected to an appropriate known
physical or chemical treatment for the purpose of imparting
hydrophilicity to the surface or for improving the strength of the
support, in accordance with the necessity.
[0436] The support is preferably paper, a polyester film or an
aluminum plate. An aluminum plate is particularly preferable
because it is excellent in dimensional stability and relatively
inexpensive and because higher hydrophilicity or strength can be
imparted to the surface by a surface treatment in accordance with
the necessity. A complex sheet in which an aluminum sheet is
laminated on a polyethylene terephthalate film is also preferable
and examples thereof are disclosed in JP-B No. 48-18327, the
disclosure of which is incorporated herein by reference.
[0437] The aluminum plate is preferably a pure aluminum plate or an
alloy plate containing aluminum as the main component and trace
amounts of heteroelements, or a plastic film on which aluminum is
laminated or vapor-deposited, or an aluminum thin film laminated
with plastic, or an aluminum alloy thin film laminated with
plastic. Examples of the heteroelements contained in the aluminum
alloy include silicon, iron, manganese, copper, magnesium, chrome,
zinc, bismuth, nickel, and titanium. The content of the
heteroelements in the alloy is preferably 10% by mass or lower.
Although a pure aluminum plate is preferable, production of
absolutely pure aluminum is difficult from the viewpoint of
refining techniques. The aluminum plate used in the invention may
be an aluminum plate containing trace amounts of
heteroelements.
[0438] The composition of the aluminum plate is not limited, and
any conventionally known aluminum plates can be used in accordance
with the necessity. The thickness of the aluminum plate is
preferably 0.1 to 0.6 mm, more preferably 0.15 to 0.4 mm, still
more preferably 0.2 mm to 0.3 mm.
[0439] When the support has a surface formed by aluminum, it is
preferable to subject the surface to a surface treatment such as a
roughening (graining) treatment, an immersion treatment in an
aqueous solution of sodium silicate, potassium fluorozirconate, or
a phosphate, or an anodizing treatment prior to use.
[0440] Various methods can be employed for the roughening of the
surface of the aluminum plate. For example, the roughening may be
conducted by: a mechanical surface roughening, an electrochemical
surface roughening (method of electrochemically dissolving the
surface) or a chemical surface roughening (method of chemically and
selectively dissolving the surface). The mechanical surface
roughening method may be a known method such as ball grinding,
brush grinding, blast grinding, buff grinding, or the transfer
method of transferring an embossed shape on an embossed roll to the
aluminum plate during the rolling of aluminum. The electrochemical
roughening method may be a method of roughening the surface in an
electrolysis solution containing hydrochloric acid or nitric acid
with alternating current or direct current, or a method of using a
mixed acid as described in JP-A 54-63902, the disclosure of which
is incorporated by reference herein.
[0441] Before the surface of the aluminum plate is roughened, the
aluminum plate may be subjected to a degreasing treatment with e.g.
a surfactant, an organic solvent or an aqueous alkali solution so
as to remove the rolling oil from the surface, in accordance with
the necessity.
[0442] In an embodiment, the aluminum plate whose surface has been
roughened is subjected to an alkali etching treatment with an
aqueous solution of potassium hydroxide, sodium hydroxide, or the
like, then to a neutralization treatment, then optionally to an
anodizing treatment which improves the abrasion resistance.
[0443] The electrolyte used in the anodizing treatment of the
aluminum plate may be selected from various electrolytes capable of
forming a porous oxide film. Generally, the electrolyte is selected
from sulfuric acid, hydrochloric acid, oxalic acid, chromic acid,
and mixed acids thereof. The concentration of the electrolyte is
determined suitably in accordance with the type of the
electrolyte.
[0444] The conditions for the anodizing treatment may be changed
depending on the electrolyte and cannot be generalized. Usually,
the concentration of the electrolyte is preferably 1 to 80% by
mass, the liquid temperature is preferably 5 to 70.degree. C., the
current density is preferably 5 to 60 A/dm.sup.2, the voltage is
preferably 1 to 100 V, and the electrolysis time is preferably 10
seconds to 5 minutes. The amount of the anodized film is preferably
1.0 to 5.0 g/m.sup.2, more preferably 1.5 to 4.0 g/m.sup.2. When
the amount of the anodized film is in this range, high printing
durability and excellent flaw resistance of non-image regions of
the planographic printing plate can be obtained.
[0445] After the surface-roughening, the aluminum plate may be
immersed in a sodium silicate solution so as to impart
hydrophilicity to the surface. For example, the aluminum plate may
be immersed in an aqueous solution of an alkali metal silicate
after anodization, as described in JP-B No. 47-5125, the disclosure
of which is incorporated herein by reference.
[0446] The anodization may be conducted by applying an electric
current to the aluminum plate (as the anode) placed in an
electrolytic liquid which is an aqueous or non-aqueous solution of
an inorganic acid (such as phosphoric acid, chromic acid, sulfuric
acid or boric acid) or an organic acid (such as oxalic acid or
sulfamic acid) or a salt thereof, or a combination of such
solutions.
[0447] A hydrophilicity-imparting treatment of the support surface
with a silicate compound may be silicate electrodeposition such as
electrodeposition disclosed in U.S. Pat. No. 3,658,662, the
disclosure of which is incorporated herein by reference. Other
examples thereof include a surface treatment which is a combination
of an electrically-grained support, the anodization described
above, and a sodium silicate treatment. Such a surface treatment is
disclosed in JP-B No. 46-27481 and JP-A Nos. 52-58602 and 52-30503.
Still other examples include a treatment in which mechanical
surface-roughening, chemical etching, electrolytic graining,
anodization, and a treatment with sodium silicate are conducted
sequentially, as described in JP-A No. 56-28893, the disclosure of
which is incorporated herein by reference.
[0448] After such treatments, the support may be undercoated with a
water-soluble resin (such as polyvinyl phosphonic acid, a polymer
or copolymer having a sulfonic acid group on a side chain, or
polyacrylic acid), a water-soluble metal salt (such as zinc
borate), an yellow dye, or an amine salt.
[0449] Another example of the hydrophilicity imparting treatment of
the support surface may be a sol-gel treated support to which
functional groups capable of undergoing addition reaction by
radicals are covalently bound, as described in JP-A No. 7-159983,
the disclosure of which is incorporated herein by reference.
[0450] The surface treatment may be a treatment of providing a
waterproof hydrophilic layer as a surface layer to an arbitrary
support. Such a surface layer may be a layer comprised of an
inorganic pigment and a binder disclosed in U.S. Pat. No. 3,055,295
and JP-A No. 56-13168 (the disclosures of which are incorporated
herein by reference), a hydrophilic swelling layer disclosed in
JP-A No. 9-80744 (the disclosure of which is incorporated herein by
reference), or a sol-gel membrane comprised of titanium oxide,
polyvinyl alcohol, and a silicate disclosed in WO 94/18005 (the
disclosure of which is incorporated herein by reference).
[0451] Other examples of methods for imparting hydrophilicity
include: alkali metal silicate methods disclosed in U.S. Pat. Nos.
2,714,066, 3,181,461, 3,280,734, and 3902734 (the disclosures of
which are incorporated herein by reference), the methods comprising
immersing or electrolyzing the support in an aqueous solution of
sodium silicate or the like; a method disclosed in JP-B No.
36-22063 (the disclosure of which is incorporated herein by
reference), the method comprising treating the support with
potassium fluorozirconate; and methods disclosed in U.S. Pat. Nos.
3,276,868, 4,153,461, and 4,689,272 (the disclosures of which are
incorporated herein by reference), the methods comprising treating
the support with polyvinyl phosphonic acid.
[0452] When the support is a support whose surface has insufficient
hydrophilicity such as polyester film, it is preferable to coat the
surface with a hydrophilic layer so as to impart hydrophilicity to
the surface. The hydrophilic layer may be selected from: a
hydrophilic layer formed by application of a coating liquid
containing colloid of an oxide or hydroxide of at least one element
selected from beryllium, magnesium, aluminium, silicon, titanium,
boron, germanium, tin, zirconium, iron, vanadium, antimony, and
transition metals disclosed in JP-A No. 2001-199175, the disclosure
of which is incorporated herein; a hydrophilic layer having organic
hydrophilic matrix obtained by crosslinking or pseudocrosslinking
of an organic hydrophilic polymer disclosed in JP-A No. 2002-79772,
the disclosure of which is incorporated herein; a hydrophilic layer
having inorganic hydrophilic matrix obtained by sol-gel conversion
caused by hydrolysis or condensation of polyalkoxysilane, a
titanate, a zirconate, or an aluminate; or a hydrophilic layer
comprised of an inorganic thin film having a surface containing a
metal oxide. Among them, the hydrophilic layer is preferably a
hydrophilic layer formed by application of a coating liquid
containing colloid of an oxide or hydroxide of silicon.
[0453] When the support is a polyester film or the like, it is
preferable to provide an antistatic layer on one side of the
support or both sides of the support. When the antistatic layer is
provided on one side, the side may be the hydrophilic layer side or
the side opposite to the hydrophilic layer side. When an antistatic
layer is provided between the support and the hydrophilic layer,
the antistatic layer improves adhesion of the hydrophilic layer.
The antistatic layer may be a polymer layer in which metal oxide
particles or matte agents are dispersed and which is disclosed in
JP-A No. 2002-79772, the disclosure of which is incorporated
herein.
[0454] The center-line average roughness of the support is
preferably 0.10 to 1.2 .mu.m. When the center-line average
roughness is in the range, contact characteristics between the
support and the polymerizable composition layer or the
photopolymerizable layer are improved and high printing durability
and stain resistance can be achieved.
[0455] The hydrophilicity-imparting treatment may be conducted in
order to make the support surface hydrophilic, in order to prevent
undesirable reactions in the photopolymerizable composition layer
or in the photopolymerizable layer, or in order to improve adhesion
of the photosensitive layer.
Sealing Treatment
[0456] The support having an anodized film which has been subjected
to the above surface treatments may be used as the support as it
is. However, for the purpose of further improving adhesion to the
upper layer, hydrophilicity, stain resistance, thermal insulating
properties etc., the support may be further subjected to optional
treatments such as: the treatment for enlarging micropores in the
anodized film described in JP-A Nos. 2001-253181 and 2001-322365
(the disclosures of which are incorporated hereinby reference), a
sealing treatment, and a surface hydrophilicity-imparting treatment
in which the support is immersed in an aqueous solution containing
a hydrophilic compound. The enlargement treatment and sealing
treatment are not limited to the examples described above, and any
known treatments can be conducted.
[0457] For example, the sealing treatment may be vapor sealing, a
treatment only with fluorozirconic acid, a treatment with sodium
fluoride, or vapor sealing involving addition of lithium
chloride.
[0458] The sealing treatment which can be conducted in the
invention is not particularly limited, and may be conducted by a
conventionally known method. The sealing treatment is preferably a
sealing treatment with an aqueous solution containing an inorganic
fluorine compound, a sealing treatment with water vapor, or a
sealing treatment with hot water. Hereinafter, these methods are
described respectively.
<Sealing Treatment with an Aqueous Solution Containing an
Inorganic Fluorine Compound>
[0459] In a sealing treatment with an aqueous solution containing
an inorganic fluorine compound, the inorganic fluorine compound to
be used is preferably a metal fluoride.
[0460] Specific examples thereof include sodium fluoride, potassium
fluoride, calcium fluoride, magnesium fluoride, sodium
fluorozirconate, potassium fluorozirconate, sodium fluorotitanate,
potassium fluorotitanate, ammonium fluorozirconate, ammonium
fluorotitanate, potassium fluorotitanate, fluorozirconic acid,
fluorotitanic acid, hexafluorosilicic acid, nickel fluoride, iron
fluoride, fluorophosphoric acid and ammonium fluorophosphate.
Preferable among these compounds are sodium fluorozirconate, sodium
fluorotitanate, fluorozirconic acid and fluorotitanic acid.
[0461] The concentration of the inorganic fluorine compound in the
aqueous solution is preferably 0.01% by mass or higher, more
preferably 0.05% by mass or higher, in respect of sufficient
sealing of micropores in the anodized film. The concentration of
the inorganic fluorine compound in the aqueous solution is
preferably 1% by mass or lower, more preferably 0.5% by mass or
lower, in respect of stain resistance.
[0462] The aqueous solution containing an inorganic fluorine
compound preferably further contains a phosphate compound. When the
phosphate compound is contained in the aqueous solution, the
hydrophilicity of the surface of the anodized film is improved thus
improving on-press developability and stain resistance.
[0463] The phosphate compound is preferably selected from metal
phosphates such as phosphates of alkali metals and phosphates of
alkaline earth metals.
[0464] Specific examples thereof include zinc phosphate, aluminum
phosphate, ammonium phosphate, diammonium hydrogen phosphate,
ammonium dihydrogen phosphate, monoammonium phosphate,
monopotassium phosphate, monosodium phosphate, potassium dihydrogen
phosphate, dipotassium hydrogen phosphate, calcium phosphate,
sodium ammonium hydrogen phosphate, magnesium hydrogen phosphate,
magnesium phosphate, ferrous phosphate, ferric phosphate, sodium
dihydrogen phosphate, sodium phosphate, disodium hydrogen
phosphate, lead phosphate, diammonium phosphate, calcium dihydrogen
phosphate, lithium phosphate, phosphotungstic acid, ammonium
phosphotungstate, sodium phosphotungstate, ammonium
phosphomolybdate, sodium phosphomolybdate, sodium phosphite, sodium
tripolyphosphate and sodium pyrophosphate. Among these, sodium
dihydrogen phosphate, disodium hydrogen phosphate, potassium
dihydrogen phosphate and dipotassium hydrogen phosphate are
preferable.
[0465] The combination of the inorganic fluorine compound and the
phosphate compound is not particularly limited. In a preferable
embodiment, the aqueous solution includes sodium fluorozirconate as
the inorganic fluorine compound and sodium dihydrogen phosphate as
the phosphate compound.
[0466] The concentration of the phosphate compound in the aqueous
solution is preferably 0.01% by mass or higher, more preferably
0.1% by mass or higher, from the viewpoint of improving on-press
developability and stain resistance. The concentration of the
phosphate compound in the aqueous solution is preferably 20% by
mass or lower, more preferably 5% by mass or lower, in respect of
the solubility.
[0467] The ratios of the respective compounds in the aqueous
solution are not particularly limited. The ratio by mass of the
inorganic fluorine compound to the phosphate compound is preferably
in the range of 1/200 to 10/1, more preferably in the range of 1/30
to 2/1.
[0468] The temperature of the aqueous solution is preferably
20.degree. C. or higher, more preferably 40.degree. C. or higher,
but preferably 100.degree. C. or lower, more preferably 80.degree.
C. or lower.
[0469] The pH of the aqueous solution is preferably 1 or higher,
more preferably 2 or higher, but preferably 11 or lower, more
preferably 5 or lower.
[0470] The method of sealing with the aqueous solution containing
an inorganic fluorine compound is not particularly limited, and
examples thereof include a dipping method and a spraying method.
Only a single kind of sealing treatment may be conducted or two or
more kinds of sealing treatments may be conducted in combination.
Each sealing treatment may be conducted only once, or may be
conducted for twice or more.
[0471] The dipping method is preferable for conducting the sealing
treatment. When the dipping method is used in the treatment, the
treatment time is preferably at least 1 second, more preferably at
least 3 seconds, but preferably 100 seconds or shorter, more
preferably 20 seconds or shorter.
<Sealing Treatment with Water Vapor>
[0472] The sealing treatment with water vapor may be conducted by,
for example, allowing the anodized film to continuously or
intermittently contact with pressurized water vapor or water vapor
of atmospheric pressure.
[0473] The temperature of the water vapor is preferably 80.degree.
C. or higher, more preferably 95.degree. C. or higher, but
preferably 105.degree. C. or lower.
[0474] The pressure of the water vapor is preferably in the range
of from (atmospheric pressure-50 mmAq) to (atmospheric pressure+300
mmAq). In an embodiment, the pressure of the water vapor is
preferably in the range of 1.008.times.10.sup.5 to
1.043.times.10.sup.5 Pa.
[0475] The duration of the contact with water-vapor is preferably 1
second or longer, more preferably 3 seconds or longer, but
preferably 100 seconds or shorter, more preferably 20 seconds or
shorter.
<Sealing Treatment with Hot Water>
[0476] The sealing treatment with hot water may be conducted, for
example by dipping an aluminum plate having an anodized film formed
thereon in hot water. The hot water may include an inorganic salt
(for example, a phosphate) or an organic salt.
[0477] The temperature of the hot water is preferably 80.degree. C.
or higher, more preferably 95.degree. C. or higher, but preferably
100.degree. C. or lower. The dipping time is preferably 1 second or
longer, more preferably 3 seconds or longer, but preferably 100
seconds or shorter, more preferably 20 seconds or shorter.
Backcoat Layer
[0478] A backcoat layer may be provided to the back side of the
support after the support is subjected to a surface treatment or
after the surface is provided with an undercoat layer.
[0479] The backcoat may be a layer comprised of an organic polymer
compound described in JP-A 5-45885 (the disclosure of which is
incorporated herein by reference) or a layer comprised of a metal
oxide obtained by hydrolysis and polycondensation of an organic or
inorganic metal compound described in JP-A No. 6-35174 (the
disclosure of which is incorporated herein by reference). It is
preferable to use silicon alkoxy compounds such as
Si(OCH.sub.3).sub.4, Si(OC.sub.2H.sub.5).sub.4,
Si(OC.sub.3H.sub.7).sub.4 and Si(OC.sub.4H.sub.9).sub.4 because
these starting materials are easily available and inexpensive.
Undercoat Layer
[0480] In the planographic printing plate precursor of the
invention, an undercoat layer may be optionally provided between
the support and the polymerizable composition layer or
photopolymerizable layer. Because the undercoat layer functions as
a thermal insulator layer, heat generated upon exposure to light
from an infrared laser can be efficiently utilized without
diffusing into the support, thus achieving higher sensitivity. In
unexposed areas, the undercoat layer improves on-press
developability by facilitating release of the polymerizable
composition layer or photopolymerizable layer from the support.
[0481] The undercoat layer material may be a silane coupling agent
having an addition-polymerizable ethylenic double bond reactive
group described in JP-A No. 10-282679 (the disclosure of which is
incorporated herein by reference) or a phosphorus compound having
an ethylenic double bond reactive group.
[0482] The coating weight (in terms of the solid content) of the
undercoat layer is preferably 0.1 to 100 mg/m.sup.2, more
preferably 3 to 30 mg/m.sup.2.
Protective Layer
[0483] In the planographic printing plate precursor of the
invention, a protective layer may be optionally provided on the
polymerizable composition layer or on the photopolymerizable layer
for the purpose of prevention of the flaw on the image recording
layer, oxygen blocking, and prevention of ablation upon exposure
with a high-intensity laser. A protective layer may be provided
particularly when the planographic printing plate precursor is to
be exposed by scanning exposure. Exposure of a planographic
printing plate precursor is conducted usually in the air, and the
protective layer prevents the incorporation of low-molecular-weight
compounds in the air (such as oxygen and basic substances) into the
image recording layer, which low-molecular-weight compounds inhibit
the image formation reaction in the photosensitive layer caused by
the exposure. In this manner, the protective layer prevents
inhibition of the image formation reaction in the air upon exposure
to light. Accordingly, the protective layer preferably has a low
permeability to low-molecular-weight compounds such as oxygen. The
protective layer preferably has a high transmittance to the light
used in the exposure. The protective layer is preferably capable of
adhering tightly to the image recording layer. The protective layer
is preferably easily removable with an on-press development after
exposure.
[0484] The protective layer having such properties has been
extensively examined and described in detail in U.S. Pat. No.
3,458,311 and JP-B No. 55-49729, the disclosures of which are
incorporated by reference herein.
[0485] The material used in the protective layer is preferably a
water-soluble polymer compound having relatively high
crystallinity. Specific examples thereof include water-soluble
polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, acidic
celluloses, gelatin, gum arabic and polyacrylic acid. When
polyvinyl alcohol is used as a main component, the protective layer
has superior basic characteristics such as oxygen impermeability
and removability upon development. The polyvinyl alcohol may be
partially substituted by groups such as esters, ethers and acetals
and may partially include other copolymerizable components insofar
as it contains unsubstituted vinyl alcohol units which impart the
oxygen blocking property and water solubility required for the
protective layer. The water-soluble polymer is preferably a mixture
including polyvinyl alcohol and 15% by mass to 50% by mass of
polyvinyl pyrrolidone, from the viewpoint of storage stability.
[0486] The polyvinyl alcohol may be a polyvinyl alcohol having a
hydrolysis degree of 71 to 100% and a molecular weight of 300 to
2400. Specific examples thereof include PVA-105, PVA-110, PVA-117,
PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS, PVA-CST, PVA-HC,
PVA-203, PVA-204, PVA-205, PVA-210, PVA-217, PVA-220, PVA-224,
PVA-217EE, PVA-217E, PVA-220E, PVA-224E, PVA-405, PVA-420, PVA-613
and L-8, all of which are manufactured by Kuraray Co., Ltd.
[0487] The components (the type of PVA and additives to be used) of
the protective layer, the coating weight, etc. are selected in
consideration of oxygen blocking property, removability upon
development, fogging property, adhesiveness, flaw resistance, and
the like. In general, as the degree of hydrolysis of PVA is
increased (as the content of unsubstituted vinyl alcohol units in
the protective layer is increased) or as the thickness of the layer
is increased, the oxygen blocking property is enhanced to improve
the sensitivity. However, excessive oxygen blocking property is not
preferred, which may result in undesired polymerization reaction
during production or raw storage, and unnecessary fogging and line
thickening upon imagewise exposure. Accordingly, the oxygen
permeability A at 25.degree. C., 1 atm is preferably
0.2.ltoreq.A.ltoreq.20 (cc/m.sup.2 day).
[0488] As other components in the protective layer, glycerin,
dipropylene glycol etc. can be added in an amount of a few % by
mass based on the amount of the (co)polymer, in order to impart
flexibility to the protective layer. Further, anionic surfactants
such as sodium alkylsulfate and sodium alkylsulfonate, amphoteric
surfactants such as alkylaminocarboxylates and
alkylaminodicarboxylates and nonionic surfactants such as
polyoxyethylene alkyl phenyl ether may be added in an amount of a
few % by mass based on the amount of the (co)polymer.
[0489] The thickness of the protective layer may be 0.05 to 4
.mu.m, preferably 0.1 to 2.5 .mu.m.
[0490] In addition, adhesion to the image region and flaw
resistance are also very important in handling of the planographic
printing plate precursor. That is, when the hydrophilic protective
layer including a water-soluble polymer is laminated on the
lipophilic polymerizable layer, the protective layer easily peels
because of insufficient adhesion between the layers, so that
defects such as insufficient film curing in the peeling portion
occur because of inhibition of the polymerization by oxygen.
[0491] Towards this problem, various proposals have been made for
the purpose of improving the adhesion between the layers. For
example, U.S. Pat. Nos. 292,501 and 44,563, JP-A 49-70702 and GB
Patent Application (Laid-Open) No. 1303578 (the disclosures of
which are incorporated herein by reference) disclose a method
comprising incorporating an acrylic emulsion, a water-insoluble
vinyl pyrrolidone-vinyl acetate copolymer, or the like in an amount
of 20 to 60% by mass into a hydrophilic polymer primarily
comprising polyvinyl alcohol and then laminating the mixture on the
polymerizable layer thereby achieving satisfactory adhesion. Any
known techniques can be applied to the protective layer in the
invention. The method for applying the protective layer is
described in detail, for example in U.S. Pat. No. 3,458,311 and
JP-A 55-49729, the disclosures of which are incorporated by
reference herein.
[0492] Further, the protective layer may have other functions. For
example, when a colorant (for example, a water-soluble dye) which
has high transmittance to the light used for exposure (for example,
760 nm to 1200 nm in the case of an infrared laser) but efficiently
absorbs lights of other wavelengths is added to the protective
layer, adaptability to safelight is improved without deteriorating
the sensitivity.
[0493] For instance, when a laser light is used as the light
source, there may be a requirement that the photosensitive
composition should have high sensitivity in the wavelength of the
light source but should not have high sensitivity outside the
wavelength range. For example, when the light source is a light
source emitting a light in an infrared region of 750 nm or longer,
the planographic printing plate precursor is substantially able to
be handled in a lighted room. However, actually, the planographic
printing plate precursor may be sensitive to a light of a shorter
wavelength such as light from a fluorescent lamp. In such a case,
it is preferable to add a coloring agent (such as a water-soluble
dye) which has high transmittance to the light from the light
source but efficiently absorbs lights of wavelengths of shorter
than 700 nm. In another example, when the light source emits a
light in a ultra-violet region of 450 nm or shorter, the
planographic printing plate precursor is substantially able to be
handled under safelight. However, in actual, the planographic
printing may be sensitive to visible lights of 500 nm or longer. In
such a case, adaptability to safelight can be improved without
reduction in sensitivity by adding a coloring agent (such as
water-soluble dye) which has high transmittance to the light from
the light source but efficiently absorbs lights of 500 nm or
longer.
[0494] Known methods can be used without limitation for exposing
the planographic printing plate precursor comprising the
polymerizable composition or the photopolymerizable layer. The
light source used for exposure of the planographic printing plate
precursor may be selected from known light sources without
particular limitation. The light emission wavelength of the light
source may be 300 nm to 1200 nm, and the light source may be a
laser selected from various lasers. The light source may be a
semiconductor laser emitting an infrared light of 760 nm to 1200
nm.
[0495] The light source is preferably a laser. The following lasers
are examples of available lasers emitting lights of 350 to 450
nm.
[0496] Examples of gas lasers include an Ar ion laser (364 nm, 351
nm, from 10 mW to 1 W), Kr ion laser (356 nm, 351 nm, from 10 mW to
1 W), and He--Cd laser (441 nm, 325 nm, from 1 mW to 100 mW);
examples of solid lasers include a combination of Nd:YAG
(YVO.sub.4) and a SHG crystal (twice) (355 nm, from 5 mW to 1 W)
and a combination of Cr:LiSAF and an SHG crystal (430 nm, 10 mW);
examples of semiconductor lasers include KNbO.sub.3, a ring
resonator (430 nm, 30 mW), a combination of a waveguide-type
wavelength converter with AlGaAs and InGaAs semiconductors (from
380 to 450 nm, from 5 mW to 100 mW), a combination of a
waveguide-type wavelength converter with AlGaInP and AlGaAs
semiconductors (from 300 to 350 nm, from 5 mW to 100 mW), and
AlGaInN (from 350 to 450 nm, 5 mW to 30 mW); and examples of pulse
lasers include a N.sub.2 laser (337 nm, from 0.1 to 10 mJ pulse)
and XeF (351 nm, from 10 to 250 mJ pulse).
[0497] In particular, AlGaInN semiconductor laser (commercially
available semiconductor laser of InGaN type, from 400 to 410 nm,
from 5 to 30 mW) is advantageous from the viewpoints of wavelength
characteristics and cost.
[0498] Examples of available light sources in the range of 450 to
700 nm include an Ar.sup.+ laser (488 nm), a YAG-SHG laser (532
nm), a He--Ne laser (633 nm), a He--Cd laser, and a red
semiconductor laser (from 650 to 690 nm). Examples of available
light sources in the range of 700 to 1200 nm include a
semiconductor laser (from 800 to 850 nm) and a Nd-YAG laser (1064
nm).
[0499] Examples of usable light sources further include a ultrahigh
pressure mercury lamp, a high-pressure mercury lamp, a
medium-pressure mercury lamp, a low-pressure mercury lamp, a
chemical lamp, a carbon arc lamp, a Xenon lamp, a metal halide
lamp, an ultra-violet laser lamp (such as an ArF excimer laser or a
KrF excimer lamp), a visible-light laser lamp, a fluorescent lamp,
a tungsten lamp, sun light, and radiation such as an electron beam,
X-ray, an ion beam or an infrared ray.
[0500] Among these, the light source for imagewise exposure of the
image recording material of the invention is preferably a light
source having an emission wavelength in the wavelength region from
near infrared to infrared region, more preferably a solid laser or
a semiconductor laser.
[0501] The exposure system may be the internal drum method, the
external drum method, or the flat bed method. When the recording
layer components are highly water-soluble, the recording layer is
soluble in neutral water or weakly alkaline water, whereby the
planographic printing plate can be exposed and developed on a
printing machine after mounted on the printing machine, thus
removing the necessity for a developing treatment of immersing the
printing plate in a liquid. This method is an example of on-press
developments.
Printing
[0502] The planographic printing method using the planographic
printing plate precursor of the invention is not particularly
limited. In the following, preferable examples of planographic
printing methods using the planographic printing plate precursor of
the invention are described. The planographic printing method of
the invention comprises: imagewise exposing a planographic printing
plate precursor having the image-recording layer described above on
a support; and conducting printing by supplying oil-based ink and
an aqueous component such as moistening water to the exposed
planographic printing plate precursor. In this method, the exposed
planographic printing plate precursor is not subjected to a
developing treatment such as a wet developing treatment with an
alkaline developer. In the method, regions of the image-recording
layer of the planographic printing plate precursor are removed by
at least one of non-alkaline water such as moistening water and
oil-based ink at the beginning of printing if the regions have not
been exposed to the laser light.
[0503] In the planographic printing method of the invention, as
described above, the planographic printing plate precursor of the
invention is imagewise expoesd to an infrared laser light and then
used for printing by supplying oil-based ink and an aqueous
component, and the method does not comprise a developing treatment
step.
[0504] In a specific example of the method, the planographic
printing plate precursor is exposed to an infrared laser light, and
then mounted on a printing machine and used for printing without a
developing treatment step. In another example of the method, the
planographic printing plate precursor is mounted on a printing
machine, and then exposed to an infrared laser light and used for
printing without a developing treatment step. However, the light
source is not limited to the infrared laser.
[0505] When printing is conducted by supplying an aqueous component
and oil-based ink to the planographic printing plate precursor
which was imagewise exposed to a laser light but has not been
subjected to a developing treatment such as a wet developing
treatment, cured recording layer in exposed regions forms oil-based
ink receiving regions having lipophylic surface and uncured
recording layer in non-exposed regions is dissolved or dispersed in
the supplied aqueous component and/or oil-based ink whereby
hydrophilic support surface is exposed.
[0506] As the result, aqueous components adhere to the hydrophilic
surface which is now exposed, and oil-based ink adheres to the
image-recording layer in the regions which were exposed to the
laser light, whereby the printing can be conducted. The first
substance to be supplied to the surface of the planographic
printing plate precursor may be an aqueous component or oil-based
ink, preferably oil-based ink from the viewpoint of preventing
contamination of the aqueous component with the recording layer in
the regions which were not exposed to the laser light. The aqueous
component may be moistening water for usual planographic printing.
The oil-based ink may be an ink for usual planographic
printing.
[0507] In this way, the planographic printing plate precursor is
developed on-press on an off-set press, and then used for printing
to produce a lot of printed sheets.
[0508] Since the recording layer of the planographic printing plate
precursor of the invention is the polymerizable composition layer
or the photopolymerizable layer of the invention, the curability of
exposed regions is superior, whereby the exposed regions can be
cured quickly by being subjected to a laser exposure to form
ink-receiving regions having hydrophobic surface with strength. In
unexposed regions, the recording layer can be removed in a short
time by contact with moistening water and/or ink because the
uncured recording layer inherently has high solubility and
dispersibility in the moistening water and/or ink. Accordingly, the
planographic printing plate precursor is particularly suitable for
planographic printing method with on-press development which
removes the necessity for a particular developing treatment.
[0509] Although the planographic printing plate precursor of the
invention has high on-press developability, the planographic
printing plate precursor can be developed by a usual process; after
imagewise exposure, the planographic printing plate precursor may
be subjected to a wet developing treatment with a developer such
that unexposed regions of the recording layer are removed to form
an image. In the following, the printing plate making with an
alkali developing treatment is described.
[0510] The developer is preferably a developer described in JP-B
No. 57-7427 (the disclosure of which is incorporated herein by
reference), and the developer may include an inorganic alkali agent
(such as sodium silicate, potassium silicate, sodium hydroxide,
potassium hydroxide, lithium hydroxide, sodium tertiary phosphate,
sodium secondary phosphate, ammonium tertiary phosphate, ammonium
secondary phosphate, sodium metasilicate, sodium bicarbonate, and
ammonia water) or an organic alkali agent (such as monoethanol
amine or diethanol amine). The concentration of such an alkaline
solution is preferably 0.1 to 10% by mass, more preferably 0.5 to
5% by mass.
[0511] The alkaline solution may further include a small amount of
a surfacetant or a small amount of an organic solvent such as
benzyl alcohol, 2-phenoxyethanol, or 2-butoxyethanol, in accordance
with the necessity. Examples of the developer include the
developers described in U.S. Pat. Nos. 3,375,171 and 3,615,480 and
JP-A Nos. 50-26601 and 58-54341 and JP-B Nos. 56-39464 and
56-42860, the disclosures of which are incorporated by reference.
The developer disclosed in JP-A No. 2002-202616 which contains a
specific aromatic nonionic surfactant is preferable from the
viewpoint of developability.
[0512] As an alternative, the planographic printing plate precursor
of the invention which was imagewise exposed to a laser light may
be developed by a developer which is a non-alkaline aqueous
solution with pH of 10 or lower. The non-alkaline aqueous solution
may be water or an aqueous solution whose main component is water
(containing 60% by mass or more of water), preferably an aqueous
solution with the same composition as a general known moistening
water, or an aqueous solution containng a surfactnt which may be
anionic, nonionic, or cationic. pH of the developer may be 2 to 10,
preferably 3 to 9, more preferably 5 to 9.
[0513] The non-alkaline aqueous solution as the developer may
contain an organic acid, an inorganic acid, or an inorganic
salt.
[0514] The organic acid may be citric acid, acetic acid, oxalic
acid, malonic acid, salicylic acid, caprylic acid, tartaric acid,
malic acid, lactic acid, levulinic acid, p-toluenesulfonic acid,
xylenesulfonic acid, phytic acid, or an organic phosphonic acid.
The organic acid may be in the form of an alkali metal salt thereof
or an ammonium salt thereof. The content of the organic acid in the
developer is preferably 0.01 to 5% by mass.
[0515] The inorganic acid or inorganic salt may be phosphoric acid,
metaphosphoric acid, ammonium primary phosphate, ammonium secondary
phosphate, sodium primary phosphate, sodium secondary phosphate,
potassium primary phosphate, potassium secondary phosphate, sodium
tripolyphosphate, potassium pyrophosphate, sodium
hexamethaphosphate, magnesium nitrate, sodium nitrate, potassium
nitrate, ammonium nitrate, sodium sulfate, potassium sulfate,
ammonium sulfate, sodium sulfite, ammonium sulfite, sodium hydrogen
sulfate, or nickel sulfate. The contant of the inorganic acid and
inorganic salt in the developer is preferably 0.01 to 5% by
mass.
[0516] Examples of anionic surfactants usable in the developer
include salts of fatty acids, salts of abietic acid, salts of
hydroxyalkane sulfonic acids, salts of alkane sulfonic acids, salts
of dialkylsulosuccinic acids, salts of linear alkylbenzene sulfonic
acids, salts of branched alkylbenzene sulfonic acids, salts of
alkylnaphthalene sulfonic acids, salts of
alkylphenoxypolyoxyethylenepropyl sulfonic acids, salts of
polyoxyethylenealkyl sulfophenyl ethers, sodium salt of
N-methyl-N-oleyltaurine, disodium salts of N-alkyl sulfosuccinic
acid monoamide, salts of petroleum sulfonic acids, sulfated castor
oil, sulfated beef tallow oil, salts of sulfuric esters of fatty
acid alkyl esters, salts of alkyl sulfates, salts of sulfuric
esters of polyoxyehtylene alkyl ethers, salts of sulfuric esters of
fatty acid monoglycerides, salts of sulfuric esters of
polyoxyethylenealkylphenyl ethers, salts of sulfuric esters of
polyoxyethylenestyrylphenyl ethers, salts of alkylphosphoric
esters, salts of phosphoric esters of polyoxyethylenealkyl ethers,
salts of phosphoric esters of polyoxyethylenealkylphenyl ethers,
partially saponified products of styrene-maleic anhydride
copolymers, partially saponified products of olefine-maleic
anhydride copolymers, and formaline condensates of salts of
naphthalene sulfonic acids. Preferable among the examples are salts
of dialkyl sulfosuccinic acids, salts of alkyl sulfates, and salts
of alkylnaphthalene sulfonic acids.
[0517] The cationic surfactant used in the developer is not
particularly limited, and may be selected from known cationic
surfactants. Examples therof include alkyl amines, quaternary
ammonium salts, salts of polyoxyethylene alkyl amines, and
polyethylene polyamine derivatives.
[0518] Examples of nonionic surfactants usable in the developer
include polyethyleneglycol-type higher alcohol ethylene oxide
adducts, alkylphenol ethylene oxide adducts, fatty acid ethylene
oxide adducts, polyhydric alcohol fatty acid ester ethylene oxide
adducts, higher alkylamine ethylene oxide adducts, fatty acid amide
ethylene oxide adducts, oil ethylene oxide adducts,
polypropyleneglycol ethyleneoxide adducts,
dimethylsiloxane-ethylene oxide block copolymers,
dimethylsiloxane-(propylene oxide-ethylene oxide) block copolymers,
polyhydric-alcohol-type fatty acid esters of glycerol, fatty acid
esters of pentaerythritol, fatty acid esters of sorbitol, fatty
acid esters of sorbitan, fatty acid esters of sucrose, alkyl ethers
of polyhydric alcohols, and fatty acid amides of alkanol
amines.
[0519] Only a single nonionic surfactant may be used, or a mixture
of two or more nonionic surfactants may be uesd. In the invention,
preferable are sorbitol fatty acid ester ethylene oxide adducts,
sorbitan fatty acid ester ethylene oxide adducts,
polypropyleneglycol ethylene oxide adducts,
dimethylsiloxane-ethylene oxide block copolymers,
dimethylsiloxane-(propylene oxide-ethylene oxide) block copolymers
and fatty acid esters of polyhydric alcohols.
[0520] The nonionic surfactant usable in the invention is
preferably a nonionic surfactant with HLB (Hydrophile-Lipophile
Balance) value of 6 or higher, more preferably 8 or higher, from
the viewpoint of stable solubility in water and miscibility with
water. The concentration of nonionic surfactants in the developer
is preferably 0.01 to 10% by mass, more preferably 0.01 to 5% by
mass.
[0521] Also usable are acetylene glycol oxyethylene adducts,
acetylene alcohol oxyethylene adducts, fluorine-based surfactants
and silicon-based surfactants.
[0522] The developer is preferably a developer containing a
nonionic surfactant from the viewpoint of suppression of
foaming.
[0523] The developer may contain an organic solvent. The organic
solvent may be an aliphatic hydrocarbon (such as hexane, heptane,
ISOPAR E, H, and G'' (manufacutred by Exon Mobil Corporation),
gasoline, or kerosene), an aromatic hydrocarbon (such as toluene or
xylene), a halogenated hydrocarbon (methylene dichloride, ethylene
dichloride, trichloroehylene, or monochlorobenzene), or any of the
polar solvents described below.
[0524] Examples of polar solvents include alcohols (such as
methanol, ethanol, propanol, isopropanol, benzyl alcohol,
ethyleneglycol monomethyl ether, 2-ethoxyethanol, diethyleneglycol
monoethyl ether, diethyleneglycol monohexyl ether,
triethyleneglycol monomethyl ether, propyleneglycol monoethyl
ether, dipropyleneglycol monomethyl ether, polyethyleneglycol
monomethyl ether, polypropyleneglycol, tetraethylene glycol,
ethyleneglycol monobutyl ether, ethylene glycol monobenzyl ether,
ethyleneglycol, monophenyl ether, methylphenyl carbinol, n-amyl
alcohol, and methylamyl alcohol), ketones (such as acetone, methyl
ethyl ketone, ethyl butyl ketone, methyl isobutyl ketone, and
cyclohexanone), esters (such as ethyl acetate, propyl acetate,
butyl acetate, amyl acetate, benzyl acetate, methyl lactate, butyl
lactate, ethyleneglycol monobutyl acetate, propyleneglycol
monomethyl ether acetate, diethyleneglycol acetate, diethyl
phthalate, and butyl levulinate), and other polar solvents (such as
triethyl phosphate, tricresyl phosphate, N-phenyl ethanolamine, and
N-phenyl diethanol amine).
[0525] When the organic solvent is not water-soluble, the organic
solvent may be mixed into the developer by using a surfactant or
the like. When the developer contains an organic solvent, the
content of the organic solvent is preferably lower than 40% by mass
from the viewpoints of safety and inflammability.
[0526] The developer may further contain water-soluble polymer
compounds such as: soybean polysaccharides, modified starches, gum
arabic, dextrin, cellulose derivatives (such as carboxymethyl
cellulose, carboxyethyl cellulose, and methyl cellulose) and
derivatives thereof, pullulan, polyvinyl alcohol and derivatives
thereof, polyvinyl pyrrolidone, polyacrylamide, acrylamide
copolymers, vinyl methyl ether-maleic anhydride copolymers, vinyl
acetate-maleic anhydride copolymers, and styrene-maleic anhydride
copolymers.
[0527] The soybean polysaccharides may be known soybean
polysaccharides, such as commercially available SOYAFIBE
manufactured by Fuji Oil Co., Ltd. of various grades. The soybean
polysaccharides are preferably such polysaccharides that 10% by
mass aqueous solutions of the respective polysaccharides have
viscosities in the range of 10 mPa/sec to 100 mPa/sec.
[0528] The modified starches may be known modified starches, such
as modified polysaccharides each obtained by: partially
decomposing, with an acid or an enzyme, a starch such as a starch
of corn, Irish potato, tapioca, rice or wheat such that the number
of glucose residues per molecule becomes 5 to 30; and then adding
oxypropylene to the partially decomposed starch in an alkali.
[0529] Only a single water-soluble polymer compound may be used, or
two or more water-soluble polymer compounds may be uesd. The
content of water-soluble polymer compounds in the developer is
preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by
mass.
[0530] The developer may further include an antiseptic agent, a
chelete compound, an antifoaming agent, or the like.
[0531] The antiseptic agent may be selected from: phenol and
derivatives thereof; formaline; imidazole derivatives; sodium
dehydroacetate; 4-isothiazoline-3-on derivatives;
benzisothiazoline-3-on; benztriazol derivatives; amidine guanidine
derivatives; quaternary ammonium salts; derivatives of pyridine,
quinoline, guanidine, and the like; diazine; derivatives of
triazol; oxazol; derivatives of oxazine; and nitrobromo alocohols
such as 2-bromo-2-nitropropane-1,3-diol,
1,1-dibromo-1-nitro-2-ethanol, and
1,1-dibromo-1-nitro-2-propanol.
[0532] The chelate compound may be selected from organic phosphonic
acids and phosphonoalkanetricarboxylic acids, such as:
ethylenediaminetetraacetic acid, potassium salts thereof, and
sodium salts thereof; diethylenetriaminepentaacetic acid, potassium
salts thereof, and sodium salts thereof;
triethylenetetraminehexaacetic acid, potassium salts thereof, and
sodium salts thereof; hydroxyethylethylenediaminetriacetic acid,
potassium salts thereof, and sodium salts thereof; nitrilotriacetic
acid and sodium salts thereof; 1-hydroxyethane-1,1-diphosphonic
acid, potassium salts thereof, and sodium salts thereof; and
aminotri(methylenephosphonic acid), potassium salts thereof, and
sodium salts thereof. The counter-cations of such salts may be
replaced by organic amines.
[0533] The antifoaming agent may be a general self-emulsifiable
silicone-type antifoaming agent, a general emulsifiable
silicone-type antifoaming agent, or a nonionic surfactant with a
HLB value of 5 or lower. The antifoaming agent is preferably a
silicone antifoaming agent. The silicone antifoaming agent may be
emulsifiable or solubilizable.
[0534] The development treatment with a non-alkaline aqueous
solution can be conducted by an automatic processor equipped with a
developer supplying unit and a rubbing member. The automatic
processor may be selected from: automatic processors which rub the
surface of an imagewise exposed planographic printing plate
precursor while transporting the planographic printing plate
precursor disclosed in JP-A Nos. 2-220061 and 60-59351 (the
disclosures of which are incorporated herein by reference); and
automatic processors which rub the surface of an imagewise exposed
planographic printing plate precursor placed on a cylinder while
rotating the cylinder disclosed in U.S. Pat. Nos. 5,148,746 and
5,568,768 and GB Patent No. 2297719 (the disclosures of which are
incorporated herein by reference). The automatic processor is
preferably an automatic processor which uses a rotatable brush roll
as the rubbing member. In the invention, after subjected to the
rubbing treatment, the planographic printing plate may be subjected
to further treatments such as water-washing, drying, and
desensitizing treatment.
[0535] The temperature of the developer may be an arbitrary
temperature, preferably 10.degree. C. to 50.degree. C.
[0536] In an embodiment, the planographic printing plate which was
developed by using a developer and replenisher is washed with
water, and then washed with a rinsing liquid containing a
surfactant or the like so as to remove the developer, and then
treated with a desensitizing liquid containing gum arabic and/or a
starch derivative. The post-treatment for the image-recording
material as a printing plate may be a combination of such
treatments.
[0537] In the process of making a planographic printing plate, the
entire surface of the planographic printing plate precursor may be
heated before exposure, during exposure, or between exposure and
development. When the planographic printing plate precursor is to
be developed on-press, it is preferable to expose the entire
surface to light or to heat the entire surface within a period from
before exposure to printing. Such heating or exposure fascilitates
image-forming reaction in the recording layer, thus improving
sensitivity, printing durability, and stability of sensitivity.
Generally, such heating or exposure conducted before development or
before printing is preferably carried out under a mild condition
which does not affect non-image regions, so as to prevent fogging
in the non-image portions. From the viewpoint, the heating
temperature is preferably 150.degree. C. or lower.
[0538] In a process for making a printing plate having a developing
treatment step, the entire surface of the planographic printing
plate precursor after development may be subjected to heating or
exposure so as to improve image strength and printing
durability.
[0539] Since post-development heating does not have the limitation
imposed in the case of pre-development heating, the heating
condition may be harsh, and may be 200 to 500.degree. C. In the
temperature range, image strength is sufficiently improved without
causing deterioration of the support or thermal decomposition of
image regions. When the planographic printing plate precursor is
subjected to scanning exposure, the method of the exposure is not
particularly limited and may be a known method.
Examples
[0540] In the following, the present invention is further described
with reference to Examples. However, Examples should not be
construed as limiting the invention. In Examples, the evaluation of
the polymerizable composition of the invention is conducted by
evaluation of a planographic printing plate precursor having a
recording layer containing the polymerizable composition.
Examples 1 to 10 and Comparative Examples 1 to 10
Preparation of Support
[0541] An aluminum plate with a thickness of 0.3 mm was immersed in
a 10% by mass aqueous sodium hydroxide solution having a
temperature of 60.degree. C. for 25 seconds so as to etch the
surface of the alminum plate. Then the aluminum plate was washed
with water, and then washed with 20% by mass nitric acid to conduct
neutralization, and then washed with water. Then, the aluminum
plate was subjected to electrolytic surface roughning in a 1% by
mass aqueous nitric acid solution with a quantity of anode
electricity of 300 C/dm.sup.2, using a sine wave alternating
current. Subsequently, the aluminum plate was immersed in a 1% by
mass aqueous sodium hydroxide solution having a temperature of
40.degree. C. for 5 seconds, then immersed in a 30% by mass aqueous
sulfuric acid solution having a temperature of 60.degree. C. to
conduct desmutting for 40 seconds. Then, the aluminum support is
subjectd to anodization for 2 minutes in a 20% by mass aqueous
sulfuric acid solution at an electric current density of 2
A/dm.sup.2 such that the thickness of the anodic oxide film was 2.7
g/m.sup.2. After the anodization, the surface roughness of he
aluinum plate was 0.3 .mu.m (in terms of Ra value according to JIS
(Japanese Industrial Standards) B0601, the disclosure of which is
incorporated herein by reference).
[0542] The backside of the obtained aluminum support was coated
with the following backcoat coating liquid by a bar coater, and
then dried at 100.degree. C. for 1 minute, so that a backcoat layer
with a coating weight after drying of 70 mg/m.sup.2 was formed on
the support.
TABLE-US-00002 <Sol-Gel Reaction Requid> Tetraethyl silicate
50 parts by mass Water 20 parts by mass Methanol 15 parts by mass
Phosphoric acid 0.05 part by mass
[0543] The above substances were mixed and stirred. 5 minutes after
initiation of the mixing, heat generation started. The mixture was
allowed to react for 60 minutes, and then a liquid having the
following composition was added to the mixture to form the backcoat
coating liquid.
TABLE-US-00003 Pyrogallol-formaldehyde condensation resin 4 parts
by mass (melecular weight 2,000) Dimethyl phthalate 5 parts by mass
Fluorine-based surfactant (N- 0.7 part by mass
butylperfluorooctanesulfonamide etylacrylate- polyoxyethylene
acrylate copolymer with a molecular weight of 20,000) Methanol
silica sol (manufactured by Nissan 50 parts by mass Kagaku
Industries Ltd., with a methanol content of 30% by mass) Methanol
800 parts by mass
Formation of Recording Layer
[0544] The aluminum support having the backcoat layer was coated
with a photopolymerizable composition (recording layer coating
liquid) with the following composition such that the coating weight
after drying was 1.5 g/m.sup.2, then dried at 100.degree. C. for 1
minute to form a recording layer.
TABLE-US-00004 <Recording layer coating liquid> Binder
polymer (specific polymer (A) or comparative polymer 0.5 g shown in
Table 2 or Polymerization initiator (compound shown in Table 2 or
3) 0.3 g Sensitizing colorant (compound shown in Table 2 or 3) 0.3
g Polymerizable compound (compound shown in Table 2 or 3) 1.5 g
Methyl ethyl ketone 9.0 g Propyleneglycol monomethyl ether 8.0 g
Methanol 10.0 g
Formation of Protective Layer
[0545] 3 mass % aqueous solution of polyvinyl alcohol
(saponification degree: 98% by mol, polymerization degree: 550) was
coated on the recording layer such that the coating weight after
drying was 2 g/m.sup.2, and then dried at 100.degree. C. for 2
minutes to form a protective layer. Tables 2 and 3 also show
whether or not the protective layer was provided.
[0546] The planographic printing plate precursors of Examples 1 to
10 and Comparative examples 1 to 10 were produced as described
above.
Exposure of Planographic Printing Plate Precursor to Light
[0547] Each of the produced planographic printing plate precursors
was subjected to scanning exposure by using a laser suitable for
the planographic printing plate precursor. Details of the exposure
conditions are as follows.
[0548] (1) Planographic printing plate precursors of Examples 1 to
5 and Comparative examples of 1 to 5
[0549] Each planographic printing plate precursor was subjected to
scanning exposure with an InGaN-type semiconductor laser having an
oscillation wavelength of 400 nm. In the exposure, the beam
diameter on the surface of the printing plate precursor was 25
.mu.m and exposure energy density was 0.15 mJ/cm.sup.2.
[0550] (2) Planographic printing plate precursors of Examples 6 to
10 and Comparative examples of 6 to 10
[0551] Each planographic printing plate precursor was subjected to
exposure with a TRENDSETTER 3244 VFS manufactured by Creo Inc.
equipped with a 40 W water-cooling infrared semiconductor laser
(830 nm). In the exposure, the output was 9 W, the rotating speed
of the external drum was 210 rpm, the energy on the surface of the
printing plate precursor was 100 mJ/cm.sup.2, and the resolution
was 2400 dpi.
Printing Plate Making
[0552] After exposure, each planographic printing plate was
attached to a Heidel KOR-D and used for printing without being
subjected to a wet developing treatment with an alkaline
developer.
Evaluation of Sensitivity
[0553] Sensitivity of each planographic printing plate precursor
was evaluated using the above-described exposure light source.
[0554] In the evaluation of the sensitivity, each planographic
printing plate precursor is developed on-press and image formation
was observed. The exposure was gradually decreased while checking
the image formation after the on-press development, so that the
minimum exposure required for image formation was determined. The
planographic printing plate precursors of Examples 1 and 6 were
assumed to be standard planographic printing plate precursors in
the respective exposure manners (with respective exposure
wavelengths). Assuming the sensitivities of the planographic
printing plate precursors of Examples 1 and 6 are 1.0 in the
respective exposure manners, the sensitivities of the other
planographic printing plate precursors are expressed in terms of
relative sensitivities to the sensitivity of the standard
planographic printing plate precursor. The relative sensitivity can
be expressed by the following formula:
relative sensitivity=(the minimum exposure required for the
standard planographic printing plate precursor/the minimum exposure
required for the planographic printing plate precursor of
interest)
[0555] Accordingly, a planographic printing plate precursor has
higher sensitivity and better characteristic if the relative
sensitivity of the planographic printing plate precursor is
higher.
Evaluation of Image Quality and Printing Durability
[0556] Each planographic printing plate precursors was subjected to
scanning exposure with the laser described above to form a 0.5%
halftone dot image (highlight). After the exposure, as described
above, each planographic printing plate precursor was directly
attached to Heidel KOR-D printing machine and developed on-press by
being supplied with ink and moistening water in a printing process,
and the printing process was continued to determine the number of
sheets (hereinafter referred to as "number S") on which the image
was printed with satisfactory quality. The number of sheets was
considered as the index representing printing durability. The
printing durability of the standard planographic printing plates
(planographic printing plates of Examples 1 and 6 in respective
exposure manners) was assumed to be 200, and the printing
durabilities of other planographic printing plates were expressed
in terms of relative value to the printing durability of the
standard planographic printing plate. In other words, the printing
durability of a planographic printing plate was expressed by the
formula:
Relative printing durability=(the number S of the planographic
printing plate of interest/the number S of the standard
planographic printing plate).times.200.
[0557] Accordingly, a planographic printing plate with a higher
relative printing durability has a better characteristic (higher
printing durability). The relative printing durability practically
reflects printing durability in the case where the printed image is
a high definition image of 0.5% halftone dot image.
Evaluation of On-Press Developability
[0558] In the above-described evaluations of the sensitivity and
the printing durability, the number of waste sheets discharged
until on-press development was completed, that is the number of
waste sheets which had been discharged until the desired image was
formed on the printing plate was considered as an index
representing the on-press developability. When the number of waste
sheets is smaller, the planographic printing plate has better
on-press developability. The number of waste sheets are preferably
50 or smaller from the practical viewpoint.
Evaluation of Storage Stability
[0559] Each sample was stored in a condition of 45.degree. C. 75%
RH (relative humidity) for 2 days, and then the sensitivity was
evaluated in the same manner as "Evaluation of Sensitivity." The
sensitivity ratio of sensitivity before storage to sensitivity
after storage was caluculated according to the following formula,
and the sensitivity ratio was considered as an index representing
storage stability. When there is no change in sensitivity, the
sensitivity ratio was 1.0. Therefore, the storage stability is
higher if the sensitivity ratio is nearer to 1.0.
Sensitivity ratio=[(sensitivity before storage)/(sensitivity after
storage at 45.degree. C. 75% RH for 2 days)]
[0560] The evaluation results for Examples 1 to 5 and Comparative
examples 1 to 5 are shown in Table 2, and the evaluation results
for Examples 6 to 10 and Comparative examples 6 to 10 are shown in
Table 3.
TABLE-US-00005 TABLE 2 Polymerization Sensitizing Polymerizable
Protective Relative Printing On-press Storage Polymer Initiator
Colorant Compound Layer Sensitivity Durability developability
Stability Example 1 Q-1 X-1 Y-1 R-1 Formed 1.0 200 29 1.0 Example 2
Q-3 X-1 Y-1 R-1 Formed 1.1 200 30 1.05 Example 3 Q-8 X-1 Y-1 R-1
Formed 1.0 180 35 1.05 Example 4 Q-10 X-2 Y-2 R-2 Formed 1.1 210 31
1.0 Example 5 Q-11 X-2 Y-2 R-1 Formed 1.0 190 32 1.05 Comp. Ex. 1
T-1 X-1 Y-1 R-1 Formed 0.9 150 103 1.2 Comp. Ex. 2 T-3 X-1 Y-1 R-1
Formed 0.8 150 110 1.1 Comp. Ex. 3 T-8 X-1 Y-1 R-1 Formed 0.9 160
106 1.2 Comp. Ex. 4 T-10 X-2 Y-2 R-2 Formed 0.9 160 131 1.2 Comp.
Ex. 5 T-11 X-2 Y-2 R-1 Formed 0.8 160 122 1.3
TABLE-US-00006 TABLE 3 Polymerization Sensitizing Polymerizable
Protective Relative Printing On-press Storage Polymer Initiator
Colorant Compound Layer Sensitivity Durability developability
Stability Example 6 Q-2 X-3 Y-5 R-3 Not Formed 1.0 200 25 1.05
Example 7 Q-10 X-3 Y-5 R-4 Not Formed 1.0 190 29 1.0 Example 8 Q-7
X-3 Y-6 R-3 Not Formed 1.1 200 31 1.0 Example 9 Q-5 X-4 Y-5 R-4 Not
Formed 1.1 200 27 1.05 Example 10 Q-1 X-4 Y-6 R-4 Not Formed 1.1
190 36 1.0 Comp. Ex. 6 T-2 X-3 Y-5 R-3 Not Formed 0.9 160 104 1.3
Comp. Ex. 7 T-10 X-3 Y-5 R-4 Not Formed 0.8 160 121 1.1 Comp. Ex. 8
T-7 X-3 Y-6 R-3 Not Formed 0.9 170 103 1.2 Comp. Ex. 9 T-5 X-4 Y-5
R-4 Not Formed 0.8 160 112 1.2 Comp. Ex. 10 T-1 X-4 Y-6 R-4 Not
Formed 0.8 170 126 1.1
[0561] Polymerization initiators (X-1 to X-4), sensitizing
colorants (Y-1 to Y-6), and polymerizable compounds (R-1 to R-4)
described in Tables 2 and 3 are shown below.
##STR00147## ##STR00148## ##STR00149##
[0562] Polymers (T-1) to (T-3), (T-5), (T-7) to (T-8), and (T-10)
to (T-11) used in Comparative examples are shown below together
with their weight-average molecular weights (Mw) and Tg. Polymers
(T-1) to (T-3), (T-5), (T-7) to (T-8), and (T-10) to (T-11) have
structures respectively similar to the structures of polymers (Q-1)
to (Q-3), (Q-5), (Q-7) to (Q-8), and (Q-10) to (Q-11) used in
Examples. For example, comparative polymer (T-1) has a similar
structure to the structure of the reprentative compound (Q-1) of
the invention except that polymer (T-1) does not have an
alkyleneoxy group on its side chain which alkyleneoxy group is
essential for the first embodiment of the invention.
##STR00150## ##STR00151## ##STR00152##
[0563] As is clear from Tables 2 and 3, the planographic printing
plate precursors having recording layers comprised of the
polymerizable compositions of the invention containing the specific
polymer (.LAMBDA.) could record image with high sensitivity, and
exhibited high on-press developability, printing durability, and
storage stability. Further, the planographic printing plate
precursors could form high-quality image. This characteristic was
clarified by the reproducibility of the high-definition 0.5%
halftone dot image. The combinations of the polymerizable
composition of the invention and suitable initiators, sensitizing
colorants, and the like provided superior results in both exposure
wavelengths of 400 nm (ultraviolet region) and 840 nm (infrared
region).
[0564] In contrast, the planographic printing plate precursors of
Comparative examples in which polymers which are out of the scope
of the invention and which do not have alkyleneoxy groups were used
exhibited worse characteristics in all of the sensitivity, the
printing durability, and the storage stability than the
planographic printing plate precursors of Examples. Particularly,
the on-press developability of the planographic printing plate
precursors of Comparative examples are lower than the practical
level.
Synthesis of Compound (M-1)
[0565] In 1000 ml three-neck flask, 133 g of 2-hydroxyethyl
methacrylate was dissolved in 520 ml of THF, and the solution was
cooled to 0.degree. C. Then, 130 g of 3-chloropropionic acid
chloride was dropped over 1 hour into the solution, using a
dropping funnel. Then, the temperature of the mixture was allowed
to gradually rise to room temperature. The mixture was stirred at
room temperature for 12 hours, and then the mixture was added to 1
L of ice-cold water. The obtained mixture was stirred for 1 hour,
and then subjected to extraction with 2 L of ethyl acetate for
three times. The obtained organic phase was washed with water, then
with a saturated aqueous solution of sodium hydrogen carbonate, and
then with a saturated saline solution, and then dried with
magnesium sulfate, and then subjected to filtration. Subsequently,
the solvent was removed in a reduced pressure by using a rotary
evaporator. The residue was purified by a silica gel column
chromatography (solvent: hexane/ethyl acetate) so that 180 g of
compound (M-1) was obtained. The structure of compound (M-1) was
confirmed by NMR, mass spectroscopy, and IR.
Synthesis of Compound (M-5)
[0566] Compound (M-5) was obtained in the same manner as the
synthesis of compound (M-1), except that 4-hydroxybutyl
methacrylate was used in place of 2-hydroxyethyl methacrylate.
Synthesis of Compound (M-13)
[0567] In 500 ml three-neck flask, 250 ml of acetone was added to
58.6 g of 2-hydroxyethyl methacrylate, and the mixture was stirred.
39.2 g of pyridine and 0.1 g of p-methoxyphenol were added to the
mixture, and the obtained mixture was cooled in an ice-bath
containing ice-cold water. After the temperature of the mixture
liquid became 5.degree. C. or lower, 114.9 g of 2-bromoisobutanoic
acid bromide was dropped to the mixture over 3 hours using a
dropping funnel. After completion of the dropping, the ice bath was
removed and the mixture was stirred for another 3 hours. The
mixture was then added to 750 ml of water and the obtained mixture
was stirred for 1 hour. The mixture was subjected to extraction
with 500 ml of ethyl acetate for 3 times using a separating funnel.
The organic phase was washed with 500 ml of 1M hydrochloric acid,
then with 500 ml of a saturated aqueous solution of sodium hydrogen
carbonate, and then with 500 ml of a saturated saline solution.
Subsequently, 100 g of magnesium sulfate was added to the organic
phase so that the organic phase was dehydrated and dried. The dried
organic phase was subjected to filtration, then the solvent was
removed in a reduced pressure, so that 120.3 g of residue was
obtained. The residue was found to be compound (M-13) by
.sup.1H-NMR, IR, and mass spectroscopy. Its purity was found to be
95% when measured by a HPLC (High Performance Liquid
Chromatography).
Synthesis of Compound (M-17)
[0568] In 500 ml three-neck flask, 54.8 g of methacrylic acid and
0.1 g of p-methoxyphenol were dissolved in 250 ml of
N,N-dimethylacetamide, and the solution was cooled in an ice bath
containing ice-cold water. After the solution was cooled to
5.degree. C. or lower, 96.8 g of DBU was dropped therein over 1
hour, and then 96.0 g of 6-bromo-1-hexanol was dropped therein over
1.5 hours. After completion of the dropping, the ice bath was
removed, and the mixture was stirred for 8 hours. The mixture was
added to 750 ml of water, and the obtained mixture was stirred for
1 hour. The mixture was subjected to extraction with 300 ml of
ethyl acetate for three times using a separating funnel. The
organic phase was washed with 300 ml of 1M hydrochloric acid, then
washed with 300 ml of a saturated aqueous solution of sodium
hydrogen carbonate, and then washed with 300 ml of a saturated
saline solution. Then, 100 g of magnesium sulfate was added to the
organic phase so that the organic phase was dehydrated and dried.
Then, the dried organic phase was subjected to filtration.
Subsequently, the solvent was removed in a reduced pressure to
obtain residue in an amount of 100.3 g. 50.0 g of the residue, 23.5
g of pyridine, and 0.1 g of p-methoxyphenol were put in a 500 ml
three-neck flask, and dissolved in 200 ml of acetone. The solution
was cooled in an ice bath containing ice-cold water. After the
solution was cooled to 5.degree. C. or lower, 68.3 g of
2-bromoisobutanoic acid bromide was dropped therein over 1.5 hours,
using a dropping funnel. After completion of the dropping, the ice
bath was removed, and the mixture was stirred for 3 hours. The
mixture was added to 500 ml of water and stirred for 1 hour. The
obtained mixture was subjected to extraction with 500 ml of ethyl
acetate for three times, using a separating funnel. The organic
phase was washed with 500 ml of 1M hydrochloric acid, and then
washed with 500 ml of a saturated aqueous solution of sodium
hydrogen carbonate, and then washed with 500 ml of a saturated
saline solution. Subsequently, 100 g of magnesium sulfate was added
to the organic phase so that the organic phase was dehydrated and
dried. The dried organic phase was then subjected to filtration.
Then, the solvent was removed in a reduced pressure to obtain 80.3
g of residue. The residue was found to be compound (M-17) by
.sup.1H-NMR, IR, and mass spectroscopy. Its purity was found to be
95% when measured by a HPLC.
Synthesis of Compound (M-32)
[0569] In 1000 ml three-neck flask, 152.6 g of 4-chloromethylstyme,
183.7 g of 2-bromoisobutanoic acid, and 0.2 g of p-methoxyphenol
were dissolved in 500 ml of N,N-dimethylacetamide. The obtained
mixture was cooled in an ice-bath containing ice-cold water. After
the temperature of the mixture liquid became 5.degree. C. or lower,
167.5 g of DBU was dropped into the mixture over 3 hours using a
dropping funnel. After completion of the dropping, the ice bath was
removed and the mixture was stirred for another 8 hours. The
mixture was then added to 1000 ml of water and the obtained mixture
was stirred for 1 hour. The mixture was subjected to extraction
with 500 ml of ethyl acetate for 3 times using a separating funnel.
The organic phase was washed with 500 ml of 1M hydrochloric acid,
then with 500 ml of a saturated aqueous solution of sodium hydrogen
carbonate, and then with 500 ml of a saturated saline solution.
Subsequently, 100 g of magnesium sulfate was added to the organic
phase so that the organic phase was dehydrated and dried. The dried
organic phase was subjected to filtration, then the solvent was
removed in a reduced pressure, so that 254.8 g of residue was
obtained. The residue was found to be compound (M-32) by
.sup.1H-NMR, IR, and mass spectroscopy. Its purity was found to be
94% when measured by a HPLC.
Synthesis of Compound (M-18)
[0570] 174.2 g of diethyleneglycol methacrylate, 138.0 g of
potassium carbonate, 0.1 g of p-methoxyphenol, and 400 ml of
acetone were put in a 1000 ml three-neck flask. The obtained
mixture was cooled in an ice-bath containing ice-cold water. After
the temperature of the mixture liquid became 5.degree. C. or lower,
229.9 g of 2-bromoisobutanoic acid bromide was dropped into the
mixture over 1.5 hours using a dropping funnel. After completion of
the dropping, the ice bath was removed and the mixture was stirred
for another 3 hours. The mixture was then added to 800 ml of water
and the obtained mixture was stirred for 1 hour. The mixture was
subjected to extraction with 500 ml of ethyl acetate for 3 times
using a separating funnel. The organic phase was washed with 500 ml
of 1M hydrochloric acid, then with 500 ml of a saturated aqueous
solution of sodium hydrogen carbonate, and then with 500 ml of a
saturated saline solution. Subsequently, 100 g of magnesium sulfate
was added to the organic phase so that the organic phase was
dehydrated and dried. The dried organic phase was subjected to
filtration, then the solvent was removed in a reduced pressure, so
that 300.1 g of residue was obtained. The residue was found to be
compound (M-18) by .sup.1H-NMR, IR, and mass spectroscopy.
Synthesis Example 1
Synthesis of Polymer (P-1) (Specific Example of the Above-Described
Synthesis Method 1)
[0571] 60 g of N,N-dimethylacetamide was placed in a 500 ml
three-neck flask provided with a condenser and a stirrer, and
heated in a nitrogen air flow to 75.degree. C. A solution obtained
by dissolving 18.4 g of compound (M-13), 7.6 g of
N,N-dimethylacrylamide, 20 g of methyl methacrylate, and 0.38 g of
V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) in 60 g
of N,N-dimethylacetamide was dropped therein over 2 hours. After
completion of the dropping, the obtained mixture was heated to
90.degree. C., and stirred for 2 hours. Subsequently, the mixture
was cooled to room temperature, then added to 3 L of water to
precipitate a polymer. The precipitated polymer was collected by
filtration, then washed with water, then dried to obtain 44 g of
polymer. The weight-average molecular weight of the polymer was
measured by a gel permeation chromatography (GPC) method using
polystyrene as the standard substance, and was found to be 110,000.
Therefore, it was confirmed that a proper polymerization had
occurred.
[0572] In a 200 ml three-neck flask, 26.0 g of the obtained polymer
and 0.1 g of p-methoxy phenol was dissolved in a mixture of 60 g of
N,N-dimethylacetamide and 60 g of acetone. The obtained solution
was cooled in an ice bath containing ice-cold water. After the
solution was cooled to 5.degree. C. or lower, 20.3 g of
1,8-diazabicyclo[5.4.0]-7-undecene (DBU) was dropped into the
solution over 1 hour using a dropping funnel. After completion of
the dropping, the ice bath was removed, and the obtained mixture
was stirred for 8 hours. The mixture was added to 2 L of water to
precipitate polymer (P-1). The precipitated polymer was collected
by filtration, then washed with water, than dried to give 18.2 g of
polymer. The obtained polymer was measured by .sup.1H-NMR, and it
was confirmed that 100% of the side chains derived from polymer
(M-13) had been converted to ehylene methacrylate groups. The
weight-average molecular weight of the polymer was measured by a
gel permeation chromatography (GPC) method using polystyrene as the
standard substance, and was found to be 100,000.
Synthesis Example 2
Synthesis of Polymer (P-2) (Specific Example of the Above-Described
Synthesis Method 2)
[0573] 35 g of methyl ethyl ketone was placed in a 300 ml
three-neck flask provided with a condenser and a stirrer, and
heated to 75.degree. C. Under nitrogen air flow, a solution
obtained by dissolving 15.6 g of 2-hydroxyethyl methacrylate, 6.9 g
of N,N-dimethylacrylamide, 12.0 g of methyl methacrylate, and 0.775
g of V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) in
35 g of mehyl ethyl ketone was dropped therein over 2.5 hours.
Then, the obtained mixture was allowed to react at 75.degree. C.
for 2 hours. Then, the mixture was cooled to 0.degree. C.
Subsequently, 10.9 g of acrylic acid chloride was dropped into the
mixture while the mixture was stirred. The obtained mixture was
allowed to react for 12 hours while the temperature of the mixture
rose gradually to room temperature. The mixture was then added to 3
L of water to precipitate a polymer. The precipitated polymer was
collected by filtration, then washed, then dried to obtain polymer
(P-2). Its NMR spectrum confirmed the introduction of acryl groups
to side chains in polymerization. The weight-average molecular
weight of the polymer was measured by a gel permeation
chromatography (GPC) method using polystyrene as the standard
substance, and was found to be 85,000.
Synthesis Example 3
Synthesis of Polymer (P-3) (Specific Example of the Above-Described
Synthesis Method 3)
[0574] 68.6 g of 1-methoxy2-propanol was placed in a 500 ml
three-neck flask provided with a condenser and a stirrer, and
heated to 75.degree. C. Under nitrogen air flow, a solution
obtained by dissolving 33.8 g of 2-allyloxyethyl methacrylate, 20 g
of methyl methacrylate, 14.8 g of N-vinyl pyrrolidone, and 0.97 g
of V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) in
68.6 g of 1-methoxy-2-propanol was dropped therein over 2.5 hours.
Then, the obtained mixture was allowed to react at 75.degree. C.
for 2 hours. Then, the mixture was subjected to filtration, then
washed, then dried to obtain polymer (P-3). The weight-average
molecular weight of the polymer was measured by a gel permeation
chromatography (GPC) method using polystyrene as the standard
substance, and was found to be 120,000.
Synthesis Example 4
Synthesis of Polymer (P-4) (Specific Example of the Above-Described
Synthesis Method 4)
[0575] 33.5 g of methyl ethyl ketone was placed in a 500 ml
three-neck flask provided with a condenser and a stirrer, and
heated to 75.degree. C. Under nitrogen air flow, a solution
obtained by dissolving 7.2 g of methacrylic acid chloride, 20 g of
t-butyl methacrylate, 6.3 g of methoxytetraethyleneglycol
monomethacrylate, and 0.37 g of V-601 (manufactured by Wako Pure
Chemical Industries, Ltd.) in 33.5 g of mehyl ethyl ketone was
dropped therein over 2.5 hours. Then, the obtained mixture was
allowed to react at 75.degree. C. for 2 hours. Then, the mixture
was cooled to 0.degree. C. Subsequently, 7.0 g of 2-allyloxyethyl
alcohol was dropped into the mixture while the mixture was stirred.
The obtained mixture was allowed to react for 12 hours while the
temperature of the mixture rose gradually to room temperature. The
mixture was then added to 3 L of water to precipitate a polymer.
The precipitated polymer was collected by filtration, then washed,
then dried to obtain polymer (P-4). Its NMR spectrum confirmed the
introduction of allyl groups to side chains in polymerization. The
weight-average molecular weight of the polymer was measured by a
gel permeation chromatography (GPC) method using polystyrene as the
standard substance, and was found to be 105,000.
Synthesis Example 5
Synthesis of Polymer (P-5) (Specific Example of the Above-Described
Synthesis Method 5)
[0576] 36 g of N,N-dimethylacetamide was placed in a 500 ml
three-neck flask provided with a condenser and a stirrer, and
heated to 75.degree. C. Under nitrogen air flow, a solution
obtained by dissolving 30 g of allyl methacrylate, 5.6 g of
2-acrylamide-2-methyl-1-propanesulfonic acid, and 0.48 g of V-601
(manufactured by Wako Pure Chemical Industries, Ltd.) in 36 g of
N,N-dimethylacetamide was dropped therein over 2.5 hours. Then, the
obtained mixture was allowed to react at 75.degree. C. for 2 hours.
Then, the mixture was subjected to filtration, then washed, then
dried to obtain polymer (P-5). The weight-average molecular weight
of the polymer was measured by a gel permeation chromatography
(GPC) method using polystyrene as the standard substance, and was
found to be 120,000.
Synthesis Example 6
Synthesis of Polymer (P-6) (Specific Example of the Above-Described
Synthesis Method 6)
[0577] 40 g of N,N-dimethylacetamide was placed in a 500 ml
three-neck flask provided with a condenser and a stirrer, and
heated to 75.degree. C. Under nitrogen air flow, a solution
obtained by dissolving 16.6 g of methacrylic acid chloride, 3.4 g
of methacrylic amide, 20 g of methyl methacrylate, and 0.65 g of
V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) in 40 g
of N,N-dimethylacetamide was dropped therein over 2.5 hours. Then,
the obtained mixture was allowed to react at 75.degree. C. for 2
hours. Then, the mixture was cooled to 0.degree. C. Subsequently,
16.9 g of 2-hydroxyethylmonobinyl ether was dropped into the
mixture while the mixture was stirred. The obtained mixture was
allowed to react for 12 hours while the temperature of the mixture
rose gradually to room temperature. The mixture was then added to 3
L of water to precipitate a polymer. The precipitated polymer was
collected by filtration, then washed, then dried to obtain polymer
(P-6). Its NMR spectrum confirmed the introduction of vinyl groups
to side chains in polymerization. The weight-average molecular
weight of the polymer was measured by a gel permeation
chromatography (GPC) method using polystyrene as the standard
substance, and was found to be 85,000.
Synthesis Examples 7 to 20
[0578] Polymers 7 to 20 were synthesized in similar manners to
Synthesis Examples 1 to 6 while changing types of monomers and
proportions of components. The weight-average molecular weight of
each polymer was measured in the same manner as in Synthesis
Examples 1 to 6. The specific polymers obtained above are shown
below with structures of structure units, mol ratios thereof, and
the measured weight-average molecular weight of the specific
polymer.
TABLE-US-00007 TABLE 4 Weight-Average Polymer Composition of
Synthesized Polymer (mol %) Molecular Weight P-1 ##STR00153##
100,000 P-2 ##STR00154## 85,000 P-3 ##STR00155## 120,000 P-4
##STR00156## 105,000 P-5 ##STR00157## 120,000
TABLE-US-00008 TABLE 5 Weight-Average Polymer Composition of
Synthesized Polymer (mol %) Molecular Weight P-6 ##STR00158##
110,000 P-7 ##STR00159## 95,000 P-8 ##STR00160## 110,000 P-9
##STR00161## 120,000 P-10 ##STR00162## 140,000
TABLE-US-00009 TABLE 6 Weight-Average Polymer Composition of
Synthesized Polymer (mol %) Molecular Weight P-11 ##STR00163##
90,000 P-12 ##STR00164## 95,000 P-13 ##STR00165## 130,000 P-14
##STR00166## 115,000 P-15 ##STR00167## 140,000
TABLE-US-00010 TABLE 7 Weight-Average Polymer Composition of
Synthesized Polymer (mol %) Molecular Weight P-16 ##STR00168##
100,000 P-17 ##STR00169## 75,000 P-18 ##STR00170## 60,000 P-19
##STR00171## 85,000 P-20 ##STR00172## 110,000
Preparation of Planographic Printing Plate Precursor
(1) Preparation of Support
<Support A>
[0579] An aluminum plate (material 1050) with a thickness of 0.3 mm
was subjected to a degreasing treatment with a 10% by mass aqueous
sodium aluminate solution at 50.degree. C. for 30 seconds so as to
remove rolling oil from surface of the aluminum plate. Then,
surface of the aluminum plate was grained by using three nylon
brushes with bundles of fibers having a fiber diameter of 0.3 mm
and an aqueous suspension (with specific gravity of 1.1 g/cm.sup.3)
of pumice having a median diameter of 25 .mu.m. Then, surface of
the aluminum plate was washed well with water. The aluminum plate
was immersed in a 25% aqueous sodium hydroxide solution having a
temperature of 45.degree. C. for 9 seconds so as to be etched, then
washed with water, then immersed in a 20% nitric acid having a
temperature of 60.degree. C. for 20 seconds, and then washed with
water. The etched amount of the grained surface was about 3
g/m.sup.2.
[0580] Then, the aluminum surface was subjected to a continuous
electrochemical surface-roughening treatment with 60 Hz alternating
voltage. The electrolytic solution used in the surface roughening
was a 1% by mass aqueous nitric acid solution (containing 0.5% by
mass of aluminum ion) and its temperature was 50.degree. C. The
waveform of the alternating voltage was a trapezoidal waveform in
which the time Tp the current took to increase from 0 to the peak
current was 0.8 msec and the duty ratio was 1:1. In the surface
roughening, the counter electrode was a carbon electrode, the
auxiliary anode was ferrite. The current density was 30 A/dm.sup.2
at the peak and the proportion of the current through the auxiliary
electrode was 5% of the current generated by the power source. In
the electrolysis with nitric acid, the anode electricity quantity
of the aluminum plate was 175 C/dm.sup.2. Subsequently, the
aluminum plate was subjected to spray washing.
[0581] Then, the aluminum plate was subjected to another
electrochemical surface roughening in a similar manner to the
above-described electrolysis with nitric acid, using 0.5% by mass
aqueous hydrochloric acid solution (containing 0.5% by mass of
aluminum ion) at a liquid temperature of 50.degree. C. with an
anode electricity quantity of the aluminum plate of 50 C/dm.sup.2.
Subsequently, the aluminum plate was washed with sprayed water. The
aluminum plate was subjected to a direct-current anodization in 15%
sulfuric acid (containing 0.5% by mass of aluminum ion) at an
electric current density of 15 A/dm.sup.2 to form anodic oxide film
of 2.5 g/m.sup.2. Then, the aluminum plate was washed with water,
then dried to give a support A. The center-line average roughness
(Ra) of the support was measured by using a needle with a diameter
of 2 .mu.m, and was found to be 0.51 .mu.m.
<Suport B>: FZP Treated Support
[0582] An aluminum plate having an anodic oxide film was prepared
in the same manner as the preparation of support A described above.
The aluminum plate was then immersed in a heated solution of
75.degree. C. at pH 3.7 containing 0.1% of sodium fluorozirconate
and 1% of sodium dihydrogen phosphate for 10 seconds to conduct
sealing, and used as support B.
<Support C>: FZP Pore-Widening Treatment
[0583] An aluminum plate having an anodic oxide film was prepared
in the same manner as the preparation of support A described above.
The aluminum plate was then treated with 1% by mass aqueous sodium
hydroxide solution having a temperature of 60.degree. C. for 10
seconds to enlarge the pores in the anodic oxide film. By this
treatment, the pore size of the anodic oxide film became 20 nm.
After the pore-widening treatment, the aluminum plate was immersed
in a heated solution of 75.degree. C. at pH 3.7 containing 0.1% of
sodium fluorozirconate and 1% of sodium dihydrogen phosphate for 10
seconds to conduct sealing, and used as support C.
<Support D>: Support Sealed by Steam
[0584] An aluminum plate having an anodic oxide film was prepared
in the same manner as the preparation of support A described above.
The aluminum plate was then exposed to saturated steam atmosphere
for 10 seconds to conduct sealing, and used as support D.
[0585] The supports A, B, C, and D were treated with a 2.5% by mass
aqueous sodium silicate solution of 30.degree. C. for 10 seconds.
The center-line average roughness (Ra) of each support was measured
by using a needle with a diameter of 2 .mu.m. As a result, it was
found that the supports A to D all had a center-line average
roughness of 0.51 .mu.m.
(2) Formation of Undercoat Layer
[0586] Each of the supports was coated with the following
undercoating liquid (1) such that the coating weight after drying
was 10 mg/m.sup.2. The coated support was used for experiments
described below.
TABLE-US-00011 Undercoating liquid (1) Undercoating compound (1)
(Molecular 0.017 g weight 30,000) Methanol 9.00 g Water 1.00 g
Undercoating Compound (1) ##STR00173##
(3) Formation of Image-Recording Layer
Example 11
[0587] An image-recording layer coating liquid (1) with the
following composition was coated on th support B by a bar-coating
method, and the coated support was dried in an oven at 100.degree.
C. for 60 seconds to form an image-recording layer with a dry
coating weight of 1.0 g/m.sup.2. The support having the
image-recording layer was used as a planographic printing plate
precursor.
[0588] The image-recording layer coating liquid (1) was obtained by
mixing the following photosensitive liquid (1) and microcapsule
liquid (1) immediately before coating.
TABLE-US-00012 <Photosensitive liquid (1)> Specific polymer
(P-7) 0.162 g Polymerization initiator (1) shown below 0.100 g
Infrared absorber (1) shown below 0.020 g Polymerizable monomer,
ARONIX M-215 0.385 g (manufactured by Toa Gosei Co., Ltd.)
Fluorine-based surfactant (10 shown below 0.044 g Methyl ethyl
ketone 1.091 g 1-methoxy-2-propanol 8.609 g <Microcapsule liquid
(1)> Microcapsule (1) synthesized as described below 2.640 g
Water 2.425 g Polymerization Initiator (1) ##STR00174## Infrared
absorber (1) ##STR00175## Fluorine-based surfactant (1)
##STR00176##
[0589] Synthesis of Microcapsule (1)
[0590] As the oil phase, 10 g of an adduct (TAKENATE D-110 N
manufactured by Mitsui Takeda Chemicals Inc.) of trimethylol
propane and xylenediisocyanate, 3.15 g of pentaerythritol
triacrylate (SR444 manufactured by Nippon Kayaku Co., Ltd.), 0.35 g
of an infrared absorber (2) shown below, 1 g of
3-(N,N-diethylamino)-6-methyl-7-anilinofluoran (ODB manufactured by
Yamamoto Chemicals Inc.), and 0.1 g of PIONIN A-41 C (manufactured
by Takemoto Oil & Fat Co., Ltd.) were dissolved in 17 g of
ethyl acetate. As the aqueous phase, 40 g of a 4% by mass aqueous
solution of PVA-205 was prepared. The oil phase and the aqueous
phase were mixed and subjected to emulsification with a homogenizer
at 12000 rpm for 10 minutes. The obtained emulsion was added to 25
g of distilled water, and then the obtained mixture was stirred at
room temperature for 30 minutes, and then stirred at 40.degree. C.
for 3 hours to form microcapsules. The obtained microcapsule liquid
was diluted with distilled water such that its solid content became
15% by mass. The average diameter of the microcapsules was 0.2
.mu.m.
Examples 12 to 20
[0591] Planographic printing plate precursors of Examples 12 to 20
having recording layers were each prepared in the same manner as
the preparation of the planographic printing plate precursor of
Example 11 except that the support and the specific polymer shown
in the Table below were used.
TABLE-US-00013 TABLE 8 Support Specific Polymer Example 12 A P-2
Example 13 A P-3 Example 14 A P-4 Example 15 B P-5 Example 16 B
P-11 Example 17 B P-12 Example 18 C P-13 Example 19 C P-14 Example
20 D P-15
Comparative Example 11
[0592] The planographic printing plate precursor of Comparative
example 11 having a recording layer was prepared in the same manner
as the preparation of the planographic printing plate precursor of
Example 11, except that the support was the support B and that the
polymer used was a comparative polymer (1) (Weight average
molecular weight 50,000) shown below.
##STR00177##
Example 21
[0593] The support A was coated with an image-recording layer
coating liquid with the following composition by a bar-coating
method, and then dried in an oven at 100.degree. C. for 60 seconds
to form an image-recording layer with a dry coating weight of 1.0
g/m.sup.2, thereby obtaininig a planographic printing plate
precursor.
TABLE-US-00014 <Image-recording layer coating liquid (2)>
Infrared absorber (2) shown below 0.05 g Polymerization initiator
(1) shown above 0.20 g Specific polymer (P-1) 0.50 g Polymerizable
monomer, ARONIX M-215 1.00 g (manufactured by Toa Gosei Co., Ltd.)
Naphthalenesulfonic acid salt of Victoria Pure Blue 0.02 g
Fluorine-based surfactant (1) shown above 0.10 g Methyl ethyl
ketone 18.0 g Infrared absorber (2) ##STR00178##
Examples 22 to 30
[0594] Planographic printing plate precursors of Examples 22 to 30
having recording layers were each prepared in the same manner as
the preparation of the planographic printing plate precursor of
Example 21 except that the support and the specific polymer shown
in the Table below were used.
TABLE-US-00015 TABLE 9 Support Specific Polymer Example 22 A P-6
Example 23 A P-8 Example 24 B P-9 Example 25 B P-10 Example 26 B
P-16 Example 27 C P-17 Example 28 C P-18 Example 29 D P-19 Example
30 D P-20
Comparative Example 12
[0595] The planographic printing plate precursor of Comparative
example 12 having a recording layer was prepared in the same manner
as the preparation of the planographic printing plate precursor of
Example 21, except that the support was the support A and that the
polymer used was a comparative polymer (2) (Weight average
molecular weight 50,000) shown below.
##STR00179##
2. Exposure and Printing
[0596] Each of the planographic printing plate precursors of
Examples and Comparative exampels was subjected to exposure with a
TRENDSETTER 3244 VX manufactured by Creo Inc. equipped with a 40 W
water-cooling infrared semiconductor laser. In the exposure, the
output was 9 W, the rotating speed of the external drum was 210
rpm, and the resolution was 2400 dpi. The image used for exposure
had thin-line chart. After exposure, each planographic printing
plate precursor was attached to the cylinder of a printing machine
SOR-M manufactured by Heidelberg without being subjected to a
developing treatment. Moistening water and ink were supplied to the
printing plate precursor. The moistening water was a mixture of an
etching solution EU-3 (manufactured by Fuji Photo Film Co., Ltd.),
water, and isopropyl alcohol (EU-3/water/isopropyl alcohol=1/89/10
by volume). The ink was TRANS-G (N) black ink manufactured by
Dainippon Ink and Chemicals Incorporated. Then, printing was
conducted at a printing speed of 6000 sheets per hour to print 100
sheets.
[0597] The number of printed sheets discharged until on-press
development of the unexposed regions of the image-recording layer
was completed and transfer of ink to the printed sheet in unexposed
regions stopped, was counted. The number was considered as an index
reflecting on-press developability. In each planographic printing
plate precursor, the number was 100 or smaller; that is printed
sheets without blemish in non-image regions could be obtained
before 100 sheets were printed.
3. Evaluation
[0598] In general, higher exposure results in higher curing degree
of the image-recording layer (photosensitive layer) while lower
exposure results in lower curing degree of the image-recording
layer, in the case of a negative planographic printin plate
precursor. When the curing degree of the image-recording layer is
too low, the printing durability of the planographic printing plate
is low, resulting in insufficient reproducibility of small dots and
thin lines. In contrast, when the curing degree of the
image-recordiing layer is high, the printing durability is high and
the reproducibility of small dots and thin lines is satisfactory.
In this example, reproducibility of thin lines and printing
durability of each negative planographic printing plate was
evaluated with respect to the same exposure condition described
above. The printing durability and reproducibility of thin lines
were considered as indexes representing sensitivity. In other
words, sensitivity of a planographic printing plate precursor is
higher if printing durability (in terms of the number of sheet the
printing plate can print) is higher. Similarly, sensitivity of a
planographic printing plate precursor is higher if reproducibility
of thin lines (in terms of the width of thin lines) is better.
(1) Reproducibility of Thin Lines
[0599] As described above, it was confirmed that a printed sheet
without ink stains in non-image regions was obtained before 100
sheets were printed. Then, another 500 sheets were printed. The
thin line chart printed on the 600 th (in total) sheet was observed
with a 25-power loupe, the original chart having thin lines with
width of 10, 12, 14, 16, 18, 20, 25, 30, 35, 40, 60, 80, 100, and
200 .mu.m, respectively. The minimum width of the ink lines without
a break was used for evaluation of reproducibility of thin
lines.
(2) Printing Durability
[0600] Printing was continued even after the print for evaluation
of thin line reproducibility was obtained. As the number of printed
sheets increased, the image-recording layer was gradually worn and
its ink receiving property lowered, resulting in decrease in ink
density on printed sheets. The number of sheets printed before the
ink density (reflection density) became (initial ink density -0.1)
was used for evaluation of printing durability. The initial ink
density refers to the ink density at starting of the printing.
[0601] The results are shown in Table 10 together with the results
of on-press developability.
TABLE-US-00016 TABLE 10 Printing On-press Reproducibility
Durability Developability of Thin Lines (Number (Number of Sheets)
(.mu.) of Sheets) Example 11 25 16 20000 Example 12 30 16 20000
Example 13 35 25 14000 Example 14 25 25 14000 Example 15 25 30
14000 Example 16 40 20 18000 Example 17 40 16 20000 Example 18 25
20 18000 Example 19 35 16 20000 Example 20 25 18 18000 Example 21
35 16 20000 Example 22 30 25 15000 Example 23 25 30 14000 Example
24 35 25 15000 Example 25 35 16 20000 Example 26 25 18 20000
Example 27 25 20 18000 Example 28 35 16 20000 Example 29 35 20
20000 Example 30 25 16 20000 Comp. Ex. 11 30 40 5000 Comp. Ex. 12
30 60 2000
[0602] As is clear from the results shown in Table 10, the
planographic printing plate precursors having photopolymerizable
layers containing the specific polymers of the invention exhibited
superior results with respect to all of the on-press,
developability, the reproducibility of thin lines, and the printing
durability. In contrast, Comparative examples 11 and 12 in which
polymers without ethylenic unsaturated bond on side chains were
used showed inferior results with respect to the reproducibility of
thin lines and the printing durability.
Examples 31 to 35
[0603] The support shown in Table 11 below was coated with an
image-recording layer coating liquid (3) with the following
composition by a bar-coating method, then dried in an oven at
100.degree. C. for 60 seconds to form an image-recording layer with
a dry coating weight of 1.0 g/m.sup.2. A protective layer coating
liquid (1) with the following composition was coated thereon to
give a dry coating amount of 0.5 g/m.sup.2, and dried at
120.degree. C. for 1 minute, to give a planographic printing plate
precursor.
TABLE-US-00017 <Image-recording layer coating liquid (3)>
Polymerization initiator (2) shown below 0.2 g Sensitizing colorant
(1) shown below 0.5 g Specific polymer compound (shown in Table 11)
6.0 g Polymerizable monomer, isocyanuric acid EO-modified 12.4 g
triacrylate (M315 manufactured by Toa Gosei Co., Ltd.) Leuco
crystalviolet 3.0 g Aluminum salt of N-nitrosophenylhydroxylamine
0.1 g as a thermal polymerization initiator Tetraethylammonium
chloride 0.1 g Fluorine-based surfactant (1) 0.1 g Methyl ethyl
ketone 70.0 g Polymerization Initiator (2) ##STR00180## Sensitizing
Dye (1) ##STR00181## <Protective layer coating liquid (1)>
Polyvinyl alcohol (saponification degree of 95% 40 g by mol,
polymerization degree of 800) Polyvinyl pyrrolidine (molecular
weight of 50,000) 5 g Poly(vinylpyrrolidine/vinyl acetate (1/1))
with 5 g molecular weight of 70,000 Water 950 g
Comparative Example 13
[0604] A planographic printing plate precursor having an
image-recording layer was prepared in the same manner as in Example
31 except that the comparative polymer (1) was used in place of the
specific polymer.
Examples 36 to 40
[0605] Planographic printing plate precursors were prepared in the
same manner as the preparation of the planographic printing plate
precursors of Examples 31 to 35, except that an image-recording
layer coating liquid (4) was used in place of the image-recording
layer coating liquid (3) described above.
TABLE-US-00018 <Image-recording layer coating liquid (4)>
Polymerization initiator (3) shown below 0.2 g Specific polymer
(shown in Table 11) 3.0 g Polymerizable monomer, isocyanuric acid
EO-modified 6.2 g triacrylate (M315 manufactured by Toa Gosei Co.,
Ltd.) Leuco crystalviolet 3.0 g Aluminum salt of
N-nitrosophenylhydroxylamine as 0.1 g a thermal polymerization
initiator Fluorine-based surfactant (1) 0.1 g Microcapsule (1) 10.0
g (in terms of solid amount) Methyl ethyl ketone 35.0 g
1-methoxy-2-propanol 35.0 g Water 10.0 g Polymerization Initiator
(3) ##STR00182##
Comparative example 14
[0606] A planographic printing plate precursor was prepared in the
same manner as in Example 36, except that a comparative polymer (2)
was used in place of the specific polymer in the formation of an
image-recording layer.
Exposure Method
[0607] Each planographic printing plate precursor was subjected to
exposure with a 375 nm or 405 nm semiconductor laser with an output
of 2 mW. In the exposure, the circumference of the external drum
was 900 mm, the drum rotating velocity was 800 rpm, and the
resolution was 2400 dpi. The time the laser took to write one pixel
is shown in Table 12.
Printing Method
[0608] After exposure, each planographic printing plate precursor
was attached to the cylinder of SOR-M manufactured by Heidelberg
without being subjected to a developing treatment. Moistening water
and ink were supplied to the printing plate precursor. The
moistening water was a mixture of an etching solution EU-3
(manufactured by Fuji Photo Film Co., Ltd.), water, and isopropyl
alcohol (EU-3/water/isopropyl alcohol=1/89/10 by volume). The ink
was TRANS-G (N) black ink manufactured by Dainippon Ink and
Chemicals Incorporated. Then, printing was conducted at a printing
speed of 6000 sheets per hour to print 100 sheets. The
image-recording layer in unexposed regions was removed on-press,
and prints without ink stains in non-image regions were
obtaind.
Evaluation of Planograhic Printing Plate Precursor
[0609] Reproducibility of thin lines, on-press developability and
printing durability were evaluated in the same manner as in
Examples 11 to 30.
<Sensitivity>
[0610] After the printing of 100 sheets for confirmation of prints
with no ink stains in non-image regions, the printing was continued
to print further 500 sheets. The minimum exposure required for
achieving uniform ink density in image regions of the 600th (in
total) sheet was determined to evaluate sensitivity.
<Safety Under White Light>
[0611] Unexposed planographic printing plate precursors were left
under a white fluorescent lump such that the light intensity on the
surface of the planographic printing plate precursors was 400 lux.
After the exposure to white light, planograhic printing plate
precursors which needed a developing treatment were subjected to a
development treatment. Then, similarly to the above, all the
planographic printing plate precursors were each attached to the
cylinder of SOR-M manufactured by Heidelberg, and used for printing
100 sheets. For each planographic printing plate precursor, the
longest time of the exposure to white light which did not cause ink
stains on the 100th sheet was measured. If the longest time is
longer, the planographic printing plate precursor can be handled
more safely under white light.
[0612] The results of the evaluations are shown in Table 12.
TABLE-US-00019 TABLE 11 Support Specific Polymer Example 31 A P-7
Example 32 A P-2 Example 33 B P-3 Example 34 C P-4 Example 35 D P-5
Example 36 A P-11 Example 37 A P-12 Example 38 B P-13 Example 39 C
P-14 Example 40 D P-15
TABLE-US-00020 TABLE 12 On-press Printing Reproducibility
Developability Durability Writing time per Sensitivity of Thin
Lines (Number of (Number of White Light Light Source pixel
(mJ/cm.sup.2) (.mu.m) Sheets) Sheets) Safety (Minutes) Example 31
405 nm 0.9 .mu.S 0.18 12 25 20000 240 Example 32 Semiconductor 0.9
.mu.S 0.2 12 30 18000 240 Example 33 Laser 0.9 .mu.S 0.2 12 35
15000 240 Example 34 0.9 .mu.S 0.23 14 25 14000 240 Example 35 0.9
.mu.S 0.22 14 25 19000 240 Example 36 375 nm 0.9 .mu.S 0.05 10 40
18000 240 Example 37 Semiconductor 0.9 .mu.S 0.07 10 40 20000 180
Example 38 Laser 100 .mu.S 0.07 10 25 18000 180 Example 39 100
.mu.S 0.15 12 35 20000 180 Example 40 1 mS 0.15 14 25 18000 180
Comp. Ex. 3 405 nm 0.9 .mu.S 0.2 12 30 5000 240 Semiconductor Laser
Comp. Ex. 4 375 nm 0.9 .mu.S 0.25 14 30 2000 180 Semiconductor
Laser
[0613] The photopolymerizable composition of the invention is
particularly suitable for a recording layer of a planographic
printing plate precursor for scanning exposure, but may be used in
other applications such as highly sensitive photo-molding material,
a hologram material utilizing change in refractive index upon
polymerization, or production of electronic materials such as
photoresists.
[0614] According to the invention, a photopolymerizable composition
is provided which can be polymerized and cured by exposure to laser
light or the like with high sensitivity such that unexposed areas
can be removed without being subjected to a wet developing
treatment with an excessive amount of aqueous alkaline solution.
According to the invention, a planographic printing plate precursor
is provided which can form image by laser exposure with high
sensitivity. Image regions thereof are excellent in adhesion to the
support, and non-image regions thereof can be removed easily in a
printing process without being subjected to a wet developing
treatment. The planographic printing plate precursor can form
high-quality image.
[0615] The invention further provides a planographic printing
method in which image can be recorded on the planographic printing
plate precursor directly from digintal data stored in a computor or
the like. In the method, the planographic printing plate precursor
is developed on-press without having been subjected to a wet
developing treatment. This method makes it possible to obtain a lot
of good prints with a practical energy amount.
[0616] The polymerizable composition of the invention can be
polymerized and cured with high sensitivity by exposure with an
infrared LD laser or an ultraviolet LD laser to form a cured film
excellent in hydrophobicity and crosslinking density. Unreacted
regions (unexposed regions) thereof have high water dispersibility,
whereby the unreacted regions can be removed without being
subjected to a wet developing treatment. A planographic pinting
plate precursor of the invention having a recording layer
containing the polymerizable composition can form image with high
sensitivity, and the planographic printing plate precursor can be
used for printing after exposure without need for a wet developing
treatment with an alkaline developer. The planographic printing
plate precursor can form high quality image.
* * * * *