U.S. patent number RE39,105 [Application Number 10/763,075] was granted by the patent office on 2006-05-23 for polymethine compounds, method of producing same, and use thereof.
This patent grant is currently assigned to Yamamoto Chemicals, Inc.. Invention is credited to Keiki Chichiishi, Shigeo Fujita, Yasuhisa Iwasaki, Nobuaki Sasaki.
United States Patent |
RE39,105 |
Fujita , et al. |
May 23, 2006 |
Polymethine compounds, method of producing same, and use
thereof
Abstract
The invention provides near infrared absorbing materials showing
high light-to-heat conversion efficiency and high sensitivity to
lasers whose emission bands are within the range of 750 nm to 900
nm, original plates for direct printing plate making, and novel
compounds which can be applied to such absorbing materials and
plates. The compounds are polymethine compounds of the general
formula (I) A detailed description of general formula (I) may be
found in the specification. ##STR00001## wherein R.sub.1 represents
an alkoxy group which may be substituted; R.sub.2 represents an
alkyl group which may be substituted; R.sub.3 and R.sub.4 each
represents a lower alkyl group or R.sub.3 and R.sub.4 taken
together represent a ring; X represents a hydrogen atom, a halogen
atom or a substituted amino group; Y represents an alkoxy group
which may be substituted or an alkyl group which may be
substituted; Z represents a charge neutralizing ion.
Inventors: |
Fujita; Shigeo (Osaka,
JP), Sasaki; Nobuaki (Kyoto, JP),
Chichiishi; Keiki (Kyoto, JP), Iwasaki; Yasuhisa
(Nara, JP) |
Assignee: |
Yamamoto Chemicals, Inc.
(Osaka, JP)
|
Family
ID: |
36424070 |
Appl.
No.: |
10/763,075 |
Filed: |
January 23, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
09598044 |
Jun 20, 2000 |
06342335 |
Jan 29, 2002 |
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Foreign Application Priority Data
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Jun 21, 1999 [JP] |
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11-174235 |
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Current U.S.
Class: |
430/270.1;
101/463.1; 548/469; 430/945; 430/302; 101/453; 430/944 |
Current CPC
Class: |
B41C
1/1008 (20130101); C09B 23/0066 (20130101); G03F
7/00 (20130101) |
Current International
Class: |
G03F
7/00 (20060101) |
Field of
Search: |
;430/270.1,270.11,270.21,302,944,945 ;101/453,463.1 ;548/469 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1 063 231 |
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Dec 2000 |
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EP |
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59-217761 |
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Dec 1984 |
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JP |
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62-82080 |
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Apr 1987 |
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JP |
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62-187091 |
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Aug 1987 |
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JP |
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62-207685 |
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Sep 1987 |
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JP |
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63-319191 |
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Dec 1988 |
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JP |
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1-131277 |
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May 1989 |
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JP |
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10-337962 |
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Dec 1998 |
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JP |
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2001-064255 |
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Mar 2001 |
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JP |
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WO 98/22146 |
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May 1998 |
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WO |
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Other References
Narayanan, Narasimhachari and Gabor Patonay. "A New Method for the
Synthesis of Heptamethine Cyanine Dyes: Synthesis of New
Near-Infrared Fluorescent Labels." J. Org. Chem. 60 (1995):
2391-2395. cited by examiner.
|
Primary Examiner: Gilliam; Barbara L.
Attorney, Agent or Firm: Birch, Stewart, Kolasch &
Birch, LLP
Claims
What is claimed is:
1. A polymethine compound of the following general formula
##STR00030## wherein R.sub.1 represents an alkoxy group which may
be substituted; R.sub.2 represents an alkyl group which may be
substituted; R.sub.3 and R.sub.4 each represents a lower alkyl
group or R.sub.3 and R.sub.4 may combinedly form a cyclic
structure; X represents a hydrogen atom, a halogen atom or a
substituted amino group; Y represents an alkoxy group which may be
substituted or an alkyl group which may be substituted; Z
represents a charge neutralizing ion.
2. A polymethine compound as claimed in claim 1 wherein R.sub.1 is
an alkoxy group containing 1.about.4 carbon atoms, R.sub.2 is an
alkyl group containing 1.about.8 carbon atoms, an alkoxyalkyl group
containing a total of 1.about.8 carbon atoms, a sulfoalkyl group
containing 1.about.8 carbon atoms or a carboxyalkyl group
containing a total of 2.about.9 carbon atoms, and Y is an alkoxy
group containing 1.about.4 carbon atoms or an alkyl group
containing 1.about.4 carbon atoms.
3. A polymethine compound as claimed in claim 1 wherein Z is
Cl.sup.-, Br.sup.-, I.sup.-, ClO.sub.4.sup.-, BF.sub.4.sup.-,
CF.sub.3CO.sub.2.sup.-, PF.sub.6.sup.-, SbF.sub.6.sup.-,
CH.sub.3SO.sub.3.sup.-, p-toluenesulfonate, Na.sup.+, K.sup.+ or
triethylammonium ion.
4. A polymethine compound as claimed in claim 1 wherein R.sub.3 and
R.sub.4 each is methyl or R.sub.3 and R.sub.4 taken together is a
cyclopentane ring or a cyclohexane ring.
5. A polymethine compound as claimed in claim 1 wherein X is H, Cl,
Br or diphenylamino.
6. A polymethine compound as claimed in claim 1 which is a
low-melting crystal modification of
2-(2-{2-chloro-3-[(1,3-dihydro-3,3,7-trimethyl-5-methoxy-1-methoxyethyl-2-
H-indol-2-ylidene)ethylidene]-1-cyclohexen-1-yl}ethenyl)-3,3,7-trimethyl-5-
-methoxy-1-methoxyethyl-indolium-tetrafluoroborate having the
following formula and showing a powder X-ray diffraction pattern
with characteristic peaks at the diffraction angles
(2.theta..+-.0.2.degree.) of 11.6.degree., 14.6.degree.,
15.6.degree., 19.6.degree. and 22.9.degree. in Cu--K.alpha. powder
X-ray diffractometry ##STR00031##
7. A polymethine compound as claimed in claim 1 which is a
high-melting crystal modification of
2-(2-{2-chloro-3-[(1,3-dihydro-3,3,7-trimethyl-5-methoxy-1-methoxyethyl-2-
H-indol-2-ylidene)ethylidene]-1-cyclohexen-1-yl}ethenyl)-3,3,7-trimethyl-5-
-methoxy-1-methoxyethyl-indolium-tetrafluoroborate having the
following formula and showing a powder X-ray diffraction pattern
with a characteristic high-intensity peak at the diffraction angle
(2.theta..+-.0.2.degree.) of 8.4.degree. in Cu--K.alpha. powder
X-ray diffractometry ##STR00032##
8. A polymethine compound as claimed in claim 1 which is a
crystalline methanol adduct of
2-(2-{2-chloro-3-[(1,3-dihydro-3,3,7-trimethyl-5-methoxy-1-methoxyethyl-2-
H-indol-2-ylidene)ethylidene]-1-cyclohexen-1-yl}ethenyl)-3,3,7-trimethyl-5-
-methoxy-1-methoxyethyl-indolium-tetrafluoroborate having the
following formula and showing a powder X-ray diffraction pattern
with characteristic peaks at the diffraction angles
(2.theta..+-.0.2.degree.) of 13.3.degree., 17.4.degree.,
19.8.degree., 21.8.degree. and 26.9.degree. in Cu--K.alpha. powder
X-ray diffractometry ##STR00033##
9. A polymethine compound as claimed in claim 1 which is an
amorphous form of
2-(2-{2-chloro-3-[(1,3-dihydro-3,3,7-trimethyl-5-methoxy-1-methox-
yethyl-2H-indol-2-ylidene)ethylidene]-1-cyclohexen-1-yl}ethenyl)-3,3,7-tri-
methyl-5-methoxy-1-methoxyethylindolium-tetrafluoroborate having
the following formula and showing a powder X-ray diffraction
pattern having no characteristic peak at the diffraction angles
(2.theta..+-.0.2.degree.) in Cu--K.alpha. powder X-ray
diffractometry ##STR00034##
.[.10. A process for producing the polymethine compound of claim 1
which comprises subjecting an indolenium compound of the following
general formula (II) and either a diformyl compound of the
following formula (III) or a dianil compound of the following
formula (IV) to condensation reaction in a dehydrating organic acid
in the presence of a fatty acid salt ##STR00035## wherein R.sub.1
represents an alkoxy group which may be substituted; R.sub.2
represents an alkyl group which may be substituted; R.sub.3 and
R.sub.4 each represents a lower alkyl group or R.sub.3 and R.sub.4
taken together represent a ring; Y represents an alkoxy group which
may be substituted or an alkyl group which may be substituted;
Z.sub.1 represents a charge neutralizing ion; n represents a number
of 0 or 1 ##STR00036## wherein X represents a hydrogen atom, a
halogen atom or a substituted amino group ##STR00037## wherein X
represents a hydrogen atom, a halogen atom or a substituted amino
group..].
11. A process for producing low-melting crystals of the polymethine
compound of claim 1 which comprises treating a crystalline solvent
adduct or amorphous form of the polymethine compound of claim 1
with a solvent.
12. A process for producing high-melting crystals of the
polymethine compound of claim 1 which comprises recrystallizing the
polymethine compound of claim 1 from a ketonic or alcoholic
solvent.
13. A near infrared absorbing material comprising the polymethine
compound claimed in claim 1.
14. An original plate for direct printing plate making which
comprises the polymethine compound of claim 1 in a light-to-heat
conversion layer constructed on a substrate.
15. A method of manufacturing a printing plate which comprises
irradiating the original plate for direct printing plate making
claimed in claim 14 with light using a semiconductor laser having a
light emission band of 750 nm.about.900 nm as a light source.
Description
TECHNICAL FIELD
The present invention relates to a novel polymethine compound, a
method of producing the same and a near infrared absorbing material
comprising the same. The polymethine compound of the present
invention absorbs in the near infrared region of 750.about.900 nm
and can be used as a near infrared absorbing material in image
recording utilizing laser beams, for example a near infrared
absorbing material in plate making utilizing laser beams or in
producing laser heat-sensitive recording media. It can further be
utilized as a spectral sensitization dye in electrophotography or
silver halide photography, or a dye for optical disks, for
instance.
BACKGROUND OF THE INVENTION
With recent advances in laser technology, systems of image
recording utilizing laser beams have been explored for implementing
high-speed recording or high-density, high-image-quality recording.
Thus, studies are in progress on image forming systems using laser
heat-sensitive recording materials or laser thermal transfer
recording materials, for instance, as recording systems in which a
laser beam is converted to heat. Furthermore, the rapid spread of
computers and progress in electronics, such as improvements in
digital image processing technology gave impetus to an active
endeavor to develop the so-called computer-to-plate technique (CTP
plate making technique), which makes printing plates directly from
digital data.
In the system of recording images through conversion of laser beams
to heat (laser thermal recording system), a light absorbing
material appropriate to the laser wavelength is used to convert the
light absorbed to heat to thereby form images. However, unless the
laser output is increased markedly, the heat energy required for
image formation can hardly be obtained. Therefore, the advent of a
light absorbing material with good light-to-heat conversion
efficiency has been awaited. In laser thermal recording,
semiconductor lasers are generally used which have light emission
bands in the near infrared region of 750 nm to 900 nm. Near
infrared absorbing materials matching such laser wavelengths
generally absorb in the visible region as well and tend to cause
objectional coloration of the background. Thus, a near infrared
absorber less absorbing in the visible region of the spectrum is
desired.
In the CTP plate making technology, known plate making methods are
classifiable into the irradiating method using a laser beam, the
method comprising writing by means of a thermal head, the method
comprising applying a voltage locally by means of a pin electrode,
the method comprising forming an ink-repelling or ink-receiving
layer with an ink jet, and so forth. Among them, the method using a
laser beam is superior in resolution and in the speed of plate
making to other techniques, so that various image forming
techniques for practicing said method have been investigated.
Further, recently, small-sized, high-output inexpensive
semiconductor lasers having light emission bands in the near
infrared region (750 nm to 900 nm) have become readily available
and are coming to be utilized as exposure light sources in plate
making.
There are two types of direct plate making utilizing laser beams,
namely the photosensitive type and heat-sensitive type. As the
photosensitive plate material, there are known the
electrophotographic system using an organic semiconductor (OPC),
the silver salt system using a silver salt, and so on. These plate
materials require a large-size and expensive equipment for the
manufacture thereof and are relatively expensive as compared with
the conventional presensitized (PS) plates. There is also the
problem associated with the disposal of the used developer.
Heat-sensitive plate materials are disadvantageous in that they are
low in sensitivity as compared with the photosensitive type plate
materials. Nevertheless, they have been intensively investigated
since they can be handled under ordinary interior conditions (in
lighted rooms) and the equipment required is small in size and
inexpensive.
All heat-sensitive plate materials require a light-to-heat
conversion layer for converting light to heat. This light-to-heat
conversion layer contains a light-to-heat conversion agent, for
example a near infrared absorbing material. It is essential for
such a light-to-heat conversion agent to absorb the laser beam used
and, for attaining improved sensitivity, it is necessary that both
the ability to absorb the laser beam used and the light-to-heat
conversion efficiency thereof be sufficiently high.
The light-to-heat conversion agent includes pigment type and dye
type agents. Carbon black is generally used as a pigment type
agent. While various substances have been proposed as dye type
agents, polymethine compounds are in widespread use. For carbon
black, there is a wide assortment of lasers to choose from.
However, carbon black is generally less efficient to absorb laser
beams as compared with dye type substances, thus calling for its
uses in an increased amount. A high-level dispersion technique is
also required.
In cases where a dye type substance is used, it is necessary that
it be highly capable of absorbing the laser beam used and that it
be well compatible with other components such as the image forming
component and resin binder and well soluble in the solvent
employed.
Polymethine compounds have a methine chain linked by conjugated
double bonds within the molecule, absorb in a broad range of the
spectrum from the visible to the near infrared region (340 to 1,400
nm) and have high extinction coefficients at their absorption
maxima. For these and other reasons, polymethine compounds are used
in various fields, for example as photosensitive dyes for silver
salt photography, photosensitive dyes for electrophotography, dyes
for laser recording, or dyes for laser light generation.
Although polymethine compounds are highly capable of absorbing
laser beams, they have several problems to be solved: the compound
matching the laser beam must be selected and most known compounds
are deficient in light stability and poorly compatible with large
forming substances and binder resins, among others.
A large number of polymethine compounds are already known and
compounds having a ring structure interrupting the methine chain
for enhanced durability have been developed. For example, Compound
A is disclosed in JP Kokai S63-319191 (page 3, Compound 9) and
Compound B in Journal of Organic Chemistry, 60, 2392, Table 1.
##STR00002##
However, Compound A and Compound B both have maximum absorption
wavelengths within the range of 785-815 and are not sensitive
enough to small-sized high-output lasers having light emissions in
the range of 820.about.840 nm. Moreover, both Compound A and
Compound B are deficient in solvent solubility and compatibility
with resins, so that the kind of binder resin that can be used is
limited.
OBJECT AND SUMMARY OF THE INVENTION
The present invention has for its object to provide a polymethine
compound which absorbs little in the visible region of the
spectrum, is highly sensitive to semiconductor lasers having
emission bands in the near infrared region (750.about.900 nm),
especially between 820.about.840 nm and, as such, is useful as a
near infrared absorbing material or suited for use in the
light-to-heat conversion layer of a laser thermal recording medium
or a CTP plate.
After a multi-pronged investigation, the inventors of the present
invention discovered a novel polymethine compound, which absorbs
little in the visible region of the spectrum, has good sensitivity
to semiconductor lasers having emission bands in the near infrared
region (750-900 nm) and a high light-to-heat conversion efficiency.
Further, this compound can be used as a near infrared absorbing
material, which can be easily processed for various
applications.
The first invention in the instant application is concerned with a
polymethine compound of the following general formula (I).
##STR00003## wherein R.sub.1 represents an alkoxy group which may
be substituted; R.sub.2 represents an alkyl group which may be
substituted; R.sub.3 and R.sub.4 each represents a lower alkyl
group or R.sub.3 and R.sub.4 taken together represent a ring; X
represents a hydrogen atom, a halogen atom or a substituted amino
group; Y represents an alkoxy group which may be substituted or an
alkyl group which may be substituted; Z represents a charge
neutralizing ion.
The second invention is concerned with a crystal modification,
crystalline methanol adduct or amorphous form of a polymethine
compound of the following formula. ##STR00004##
The third invention is concerned with a process for producing a
polymethylene compound of the above general formula (I) which
comprises condensing an indolenium compound of the following
general formula (II) with either a diformyl compound of the
following general formula (III) or a dianil compound of the
following general formula (IV) using a dehydrating organic acid in
the presence of a fatty acid salt. ##STR00005## wherein R.sub.1
represents an alkoxy group which may be substituted; R.sub.2
represents an alkyl group which may be substituted; R.sub.3 and
R.sub.4 each represents a lower alkyl group or R.sub.3 and R.sub.4
taken together represent a ring; Y represents an alkoxy group which
may be substituted or an alkyl group which may be substituted;
Z.sub.1 represents a charge neutralizing ion; n represents a number
of 0 or 1, ##STR00006## wherein X represents a hydrogen atom, a
halogen atom or a substituted amino group, ##STR00007## wherein X
represents a hydrogen atom, a halogen atom or a substituted amino
group.
The fourth invention is concerned with a process for producing a
high-melting crystalline compound which comprises recrystallizing
said polymethine compound of the first invention from a ketonic or
an alcoholic solvent.
The fifth invention is concerned with a process for producing a
low-melting crystalline compound which comprises treating a
crystalline solvate or amorphous form of said polymethine compound
of the first invention with a herein-defined solvent.
The sixth invention is concerned with a near infrared absorbing
material comprising said polymethine compound of the first
invention.
The seventh invention is concerned with an original plate for
direct printing plate (CTP printing plate) containing said
polymethine compound of the first invention in its light-to-heat
conversion layer as constructed on a support.
The eighth invention is concerned with a method of manufacturing a
printing plate which comprises irradiating the original plate for
direct printing plate of the seventh invention using a
semiconductor laser having a light emission band of 750.about.900
nm as a light source.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an IR absorption spectrum of the polymethine compound
according to Example 1.
FIG. 2 is an IR absorption spectrum of the polymethine compound
according to Example 2.
FIG. 3 is an IR absorption spectrum of the polymethine compound
according to Example 3.
FIG. 4 is an IR absorption spectrum of the polymethine compound
according to Example 4.
FIG. 5 is an IR absorption spectrum of the polymethine compound
according to Example 5.
FIG. 6 is an IR absorption spectrum of the polymethine compound
according to Example 6.
FIG. 7 is an IR absorption spectrum of the polymethine compound
according to Example 7.
FIG. 8 is an IR absorption spectrum of the polymethine compound
according to Example 8.
FIG. 9 is a VIS-NIR absorption spectrum of the polymethine compound
according to Example 1 in diacetone alcohol.
FIG. 10 is a VIS-NIR absorption spectrum of the polymethine
compound according to Example 5 in diacetone alcohol.
FIG. 11 is a VIS-NIR absorption spectrum of the polymethine
compound according to Example 7 in diacetone alcohol.
FIG. 12 is a powder X-ray diffraction pattern of the polymethine
compound according to Example 9.
FIG. 13 is a powder X-ray diffraction pattern of the polymethine
compound according to Example 10.
FIG. 14 is a powder X-ray diffraction pattern of the polymethine
compound according to Example 11.
FIG. 15 is a powder X-ray diffraction pattern of the polymethine
compound according to Example 12.
DETAILED DESCRIPTION OF THE INVENTION
In the following, the present invention is described in detail.
[Polymethine compound]
First, the polymethine compound of the following general formula
(I) according to the first invention and the crystal modification,
crystalline methanol adduct or amorphous form of
2-(2-{2-chloro-3-[(1,3-dihydro-3,3,7-trimethyl-5-methoxy-1-methoxyethyl-2-
H-indol-2-ylidene)ethylidene]-1-cyclohexen-1-yl}ethenyl)-3,3,7-trimethyl-5-
-methoxy-1-methoxyethylindolium-tetrafluoroborate [Compound species
(55)] according to the second invention are now described in
detail. ##STR00008## wherein R.sub.1 represents an alkoxy group
which may be substituted; R.sub.2 represents an alkyl group which
may be substituted; R.sub.3 and R.sub.4 each represents a lower
alkyl group or R.sub.3 and R.sub.4 taken together represent a ring;
X represents a hydrogen atom, a halogen atom or a substituted amino
group; Y represents an alkoxy group which may be substituted or an
alkyl group which may be substituted; Z represents a charge
neutralizing ion.
The alkoxy group for R.sub.1, when it is an unsubstituted alkoxy
group, is preferably a group of 1.about.8 carbon atoms,
particularly 1-4 carbon atoms.
The alkoxy group R.sub.1, when substituted, may have such
substituents as alkyloxy, alkylthio, hydroxy and halogen, although
alkyloxy groups are preferred. The alkoxy group R.sub.1 having an
alkyloxy group is preferably a group containing a total of
2.about.8 carbon atoms, more preferably a total of 2-4 carbon
atoms.
To mention specific examples, the alkoxy group R.sub.1 includes
methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, iso-butoxy,
sec-butoxy, n-pentoxy, iso-pentoxy, n-octyloxy, 2-ethylhexyloxy,
methoxymethoxy, 2-methoxyethoxy and 2-ethoxyethoxy.
When R.sub.2 represents an unsubstituted alkyl group, this group is
preferably a straight-chain or branched-chain alkyl group of 1 to
18 carbon atoms, more preferably a straight-chain or branched-chain
alkyl group of 1 to 8 carbon atoms. Examples are methyl, ethyl,
n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, n-pentyl,
isopentyl, neopentyl, n-hexyl, isohexyl, sec-hexyl, 2-ethylbutyl,
n-heptyl, isoheptyl, sec-heptyl, n-octyl, 2-ethylhexyl, n-decyl,
n-dodecyl, n-pentadecyl and n-octadecyl, among others.
When R.sub.2 represents a substituted alkyl group, this group may
be an alkoxyalkyl group, a sulfoalkyl group or a carboxyalkyl
group, for instance. The alkoxyalkyl group mentioned just above
preferably contains 2 to 8 carbon atoms. As examples, there may be
mentioned 2-methoxyethyl, 3-methoxypropyl, 4-methoxybutyl,
2-ethoxyethyl, 3-ethoxypropyl, 4-ethoxybutyl, 2-n-propoxyethyl,
2-isopropoxyethyl, 3-n-propoxypropyl, 4-n-propoxybutyl,
2-methoxy-2-ethoxyethyl and 2-ethoxy-2-ethoxyethyl.
The sulfoalkyl group mentioned above for R.sub.2 is preferably a
straight-chain or branched-chain sulfoalkyl group of 1 to 18 carbon
atoms, more preferably a straight-chain or branched-chain
sulfoalkyl group of 1 to 8 carbon atoms. Preferably, at least one
of these sulfoalkyl groups represented by R.sub.2 be in the form of
a salt with an alkali metal ion or an alkylammonium ion. As
examples of such sulfoalkyl group, there may be mentioned
2-sulfoethyl, 3-sulfopropyl, 3-sulfobutyl, 4-sulfobutyl,
4-sulfo-3-methylbutyl, 2-(3-sulfopropoxy)ethyl,
2-hydroxy-3-sulfopropyl, 3-sulfo-2-(2-ethoxy)ethoxypropoxy,
5-sulfopentyl, 6-sulfohexyl, 8-sulfooctyl and 6-sulfo-2-ethylhexyl,
and these may each be in the form of a salt with an alkali metal
ion or an alkylammonium ion.
The carboxyalkyl group mentioned above for R.sub.2 is preferably a
straight-chain or branched-chain carboxyalkyl group of 2 to 18
carbon atoms, more preferably a straight-chain or branched-chain
carboxyalkyl group of 2 to 9 carbon atoms. Preferably, at least one
of these carboxyalkyl groups represented by R.sub.2 is in the form
of a salt with an alkali metal ion or an alkylammonium ion. As
examples of such carboxyalkyl group, there may be mentioned
2-carboxyethyl, 3-carboxypropyl, 3-carboxybutyl, 4-carboxybutyl,
4-carboxy-3-methylbutyl, 2-(3-carboxypropoxy)ethyl,
2-hydroxy-3-carboxypropyl, 3-carboxy-2-(2-ethoxy) ethoxypropoxy,
5-carboxypentyl, 6-carboxyhexyl, 8-carboxyoctyl and
6-carboxy-2-ethylhexyl, and these may each be in the form of a salt
with an alkali metal ion or an alkylammonium ion.
The lower alkyl group represented by each of R.sub.3 and R.sub.4
may, for example, be methyl, ethyl, n-propyl, isopropyl, n-butyl,
isobutyl or sec-butyl.
The ring structure formed by R.sub.3 and R.sub.4 taken together
may, for example, be a cyclopropane, cyclobutane, cyclopentane,
cyclohexane or cycloheptane ring. Among them, the cyclobutane,
cyclopentane and cyclohexane rings are preferred.
X represents hydrogen, halogen, (e.g. F, Cl, Br, I), or a
substituted amino group, such as ethylamino, phenylamino,
diphenylamino or morpholino, preferably Cl, Br or
diphenylamino.
When Y is an unsubstituted alkoxy group, it is preferably an alkoxy
group of 1.about.8 carbon atoms, more preferably 1.about.4 carbon
atoms.
When Y is a substituted alkoxy group, the substituent includes
alkyloxy, alkylthio, hydroxy and halogen, preferably alkyloxy. When
Y is an alkoxy group having an alkyloxy group as a substituent, it
is preferably an alkoxy group containing a total of 2.about.8
carbon atoms, more preferably one containing 2-4 carbon atoms.
The alkoxy group Y, as such, includes methoxy, ethoxy, n-propoxy,
iso-propoxy, n-butoxy, iso-butoxy, sec-butoxy, n-pentoxy,
iso-pentoxy, n-octyloxy, 2-ethylhexyloxy, 2-methoxyethoxy and
2-ethoxyethoxy, among others.
When Y is an unsubstituted alkyl group, it is preferably a
straight-chain or branched-chain alkyl group of 1.about.8 carbon
atoms, more preferably one of 1.about.4 carbon atoms. As examples,
there may be mentioned methyl, ethyl, n-propyl, isopropyl, n-butyl,
isobutyl, sec-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl,
isohexyl, sec-hexyl, 2-ethylbutyl, n-heptyl, isoheptyl, sec-heptyl,
n-octyl and 2-ethylhexyl.
When Y is a substituted alkyl group, the substituent includes
alkyloxy, alkylthio, hydroxy, halogen, etc. but is preferably
alkyloxy. When Y is an alkyl group having an alkyloxy group as a
substituent, it is preferably one containing a total of 2.about.4
carbon atoms. As specific examples, there may be mentioned
2-methoxyethyl, 3-methoxypropyl, 4-methoxybutyl, 2-ethoxyethyl,
3-ethoxypropyl, 4-ethoxybutyl, 2-n-propoxyethyl,
2-iso-propoxyethyl, 3-n-propoxypropyl, 4-n-propoxybutyl,
2-methoxy-2-ethoxyethyl, and 2-ethoxy-2-ethoxyethyl.
Z represents a charge neutralizing ion and may, for example, be
F.sup.-, Cl.sup.-, Br.sup.-, I.sup.-, BrO.sub.4.sup.-,
ClO.sub.4.sup.-, p-toluenesulfonate, CH.sub.3SO.sub.3.sup.-,
BF.sub.4.sup.-, CH.sub.3CO.sub.2.sup.-, CF.sub.3CO.sub.2.sup.-,
PF.sub.6.sup.-, SbF.sub.6.sup.-, Na.sup.+, K.sup.+ or
triethylammonium ions. Particularly preferred among these are
Cl.sup.-, Br.sup.-, I.sup.-, ClO.sub.4.sup.-, p-toluenesulfonate,
CH.sub.3SO.sub.3.sup.-, BF.sub.4.sup.-, CF.sub.3CO.sub.2.sup.-,
PF.sub.6.sup.-, SbF.sub.6.sup.-, Na.sup.+, K.sup.+, and
triethylammonium ion.
Z represents a charge neutralizing ion and may, for example, be
F.sup.-, Cl.sup.-, Br.sup.-, I.sup.-, BrO.sub.4.sup.-,
ClO.sub.4.sup.-, p-toluenesulfonate, CH.sub.3SO.sub.3.sup.-,
BF.sub.4.sup.-, CH.sub.3CO.sub.2.sup.-, CF.sub.3CO.sub.2.sup.-,
PF.sub.6.sup.- or SbF.sub.6.sup.-. Particularly preferred among
these are Cl.sup.-, Br.sup.-, I.sup.-, CO.sub.4.sup.-,
p-toluenesulfonate, CH.sub.3SO.sub.3.sup.-, BF.sub.4.sup.-,
CF.sub.3CO.sub.2.sup.-, PF.sub.6.sup.- and SbF.sub.6.sup.-.
The following is a partial listing of the preferred examples of the
polymethine compound of general formula (I). ##STR00009##
##STR00010## ##STR00011## ##STR00012## ##STR00013## ##STR00014##
##STR00015## ##STR00016## ##STR00017## ##STR00018## ##STR00019##
##STR00020## ##STR00021##
Among the compounds (1) through (65) mentioned above as specific
examples, the compounds represented by the following general
formula (V) may alternatively be represented by the general formula
(VI) given below. ##STR00022## wherein R.sub.1.about.R.sub.4, X and
Y are respectively as defined above; M represents Na, K or
triethylammonium.
For example, Compound (51) may optionally be written as follows.
##STR00023##
Among specific polymethine compounds of general formula (I)
according to the invention, some may occur as crystal
modifications, crystalline solvates and amorphous compounds. For
example, Compound (55) may exist as the a-crystal (low-melting
compound), which, in the powder X-ray diffractometry using the
Cu--K.alpha. rays, shows characteristic peaks at the diffraction
angles (2.theta..+-.0.2.degree.) of 11.6.degree., 14.6.degree.,
15.6.degree., 19.6.degree. and 22.9.degree., the .beta.-crystal
(high-melting compound) which shows a characteristically strong
peak at the diffraction angles (2.theta..+-.0.2.degree.) of
8.4.degree., the crystalline methanol adduct which shows
characteristic peaks at the diffraction angles
(2.theta..+-.0.2.degree.) of 13.3.degree., 17.4.degree.,
19.8.degree., 21.8.degree. and 26.9.degree., and the amorphous
compound showing no characteristic diffraction
(2.theta..+-.0.2.degree.) peak.
[Method for production of the polymethine compound and its crystal
modification]
The polymethine compound of the present invention can be typically
produced by subjecting an indolenium compound represented by the
general formula (II) and a diformyl compound represented by the
general formula (III) or a dianil compound represented by the
general formula (IV) to condensation reaction in the presence of a
fatty acid salt in a dehydrating organic acid. ##STR00024## (In the
above formula, R.sub.1.about.R.sub.4, Y, Z.sub.1 and n are
respectively as defined above.) ##STR00025## (In the above formula,
X is as defined above.) ##STR00026## (In the above formula, X is as
defined above.)
In the above condensation reaction, the fatty acid salt is, for
example, sodium acetate, potassium acetate, calcium acetate, sodium
propionate, potassium propionate or the like.
Such fatty acid salt is used generally in an amount of about 0.1 to
5 moles, preferably about 0.5 to 2 moles, per mole of the compound
of general formula (III).
As the dehydrating organic acid, there may be mentioned acetic
anhydride, propionic anhydride, butyric anhydride,
.gamma.-butyrolactone and the like.
Such dehydrating organic acid is used generally in an amount of
about 10 to 100 moles, preferably about 20 to 50 moles, per mole of
the compound of general formula (II).
As to the ratio of the compound of general formula (II) to the
compound of general formula (III) or (IV) the latter is used
generally in an amount of about 0.2 to 1.5 moles, preferably about
0.4 to 0.7 moles, per mole of the former.
The above reaction can proceed generally to about 10 to 150.degree.
C., preferably at room temperature to 120.degree. C., and will go
to completion generally in several minutes to about 3 hours.
After the reaction, the desired product can be readily isolated
from the reaction mixture, for example, by pouring a poor solvent,
such as water, methanol, ethanol, n-propanol, isopropanol or
n-butanol, into said mixture or discharging said mixture into a
poor solvent such as water, methanol, ethanol, n-propanol,
isopropyl alcohol or n-butanol. The product can be readily purified
in the conventional manner, for example by recrystallization,
columnwise separation and/or other appropriate means.
Some species of the polymethine compound of general formula (I)
according to the invention may exist as crystal modification,
crystalline solvates or amorphous forms and, depending on the
method of isolation prior to purification and/or the method of
purification, may each be available as a crystalline modification,
crystalline solvate or an amorphous form or a mixture thereof.
Among such forms of the polymethine compound of the invention, the
low-melting compound can be produced by treating the crystalline
solvate or amorphous compound with a solvent, such as a ketone, an
alcohol, or a mixture thereof with an ester and/or ether, for
example, by the contact method. This treatment is preferably
carried out under conditions avoiding recrystallization, for
example by dispersing the compound in a solvent the amount and
temperature of which are so controlled that the solid polymethine
compound is not completely dissolved. The contact treatment
includes not only dispersing the polymethine compound in such a
solvent or merely contacting the compound with the solvent.
The high-melting compound is a thermally stable crystalline
compound and can be produced by a recrystallization method using a
solvent in which the low-melting compound, crystalline solvate or
amorphous compound or a mixture of the low-melting compound,
high-melting compound, crystalline solvate and amorphous compound
is thoroughly soluble, such as a ketone, an alcohol or a
ketone-alcohol mixture. This recrystallization is preferably
carried out by dissolving the polymethine compound thoroughly in
the solvent and allowing the system to ripen gradually or adding
seed crystals.
The ketone which can be used for such contact treatment or
recrystallization includes a variety of carbonyl-containing
solvents such as acetone, methyl ethyl ketone, methyl propyl
ketone, methyl butyl ketone, methyl isopropyl ketone, methyl amyl
ketone, diethyl ketone, ethyl butyl ketone, dipropyl ketone,
diusopropyl ketone, diacetone alcohol, cyclohexanone, etc. The
alcohol includes but is not limited to methanol, ethanol,
n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol,
tert-butanol, n-amyl alcohol methylamyl alcohol, 2-ethylhexanol,
n-octanol, cyclohexanol and 2-ethylcyclohexanol. The ester which
can be used for the contact treatment includes methyl acetate,
ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl
acetate, isoamyl acetate, n-butyl butyrate, etc., and the ether
includes diethyl ether, isopropyl ether, n-butyl ether and diglyme,
among others.
The amount of the solvent to be used in the contact treatment for
production of the low-melting compound is dependent on the
solubility of the polymethine compound therein and may be
2.about.70 times by weight, preferably 3.about.50 times by weight,
within the range not causing complete dissolution of the
polymethine compound. If the amount of the solvent exceeds the
above range, the product yield will be reduced to sacrifice the
efficiency of production. The treating temperature varies with the
kind of solvent but is generally about -10.about.70.degree. C.,
preferably 0.about.50.degree. C. To the solvent for the dispersion
treatment, poor solvents such as esters and/or ethers can be
added.
The amount of the recrystallization solvent for production of the
high-melting compound is also dependent on the solubility of the
polymethine compound therein, and may be 3.about.100 times by
weight, preferably 5.about.70 times by weight, based on the
polymethine compound within the range in which the polymethine
compound is completely soluble. If the amount of the solvent is too
small, the crystalline solvate tends to form under certain
conditions. If the amount of the solvent is too large, the product
yield will be reduced to sacrifice the efficiency of production.
The recrystallization temperature is dependent on the solvent used
but is generally about 20.about.150.degree. C., preferably
30.about.120.degree. C. As the recrystallization solvent, a
ketone-alcohol mixture can be used.
Among species of the compound of general formula (I) according to
the invention, the compound of the following formula, for instance,
may assume a plurality of distinct forms varying in powder X-ray
diffraction pattern, namely the low-melting compound (m.p.
195.about.197.degree. C., .alpha.-crystal), high-melting compound
(m.p. 204.about.206.degree. C., .beta.-crystal), crystalline
methanol adduct, and amorphous compound. ##STR00027##
According to the method of isolation prior to purification and/or
the method of purification, the above polymethine compound may
assume the low-melting compound, high-melting compound, crystalline
solvate or amorphous compound or a mixture of the low-melting
compound, high-melting compound, crystalline solvate and amorphous
compound.
The low-melting compound and high-melting compound can be
respectively produced by the methods described hereinbefore. The
crystalline methanol adduct can be produced by a procedure which
comprises dissolving the high-melting compound, low-melting
compound or amorphous compound or a mixture thereof in methanol,
concentrating the solution under reduced pressure until the residue
becomes 2.about.5 times the amount of the solid matter and
filtering the same. The amorphous compound can be produced by a
procedure which comprises dissolving the isolated high-melting
compound, low-melting compound, crystalline methanol adduct or
amorphous compound or a mixture thereof thoroughly in acetone,
concentrating the solution under reduced pressure, and drying the
residue.
The compound represented by the general formula (II) can be
synthesized, for example, by the method described in, inter alia,
JP Kokai H01-131277.
The diformyl compound represented by the general formula (III) can
be synthesized, for example, by the method described in Journal of
Organic Chemistry, 42, 885-888 (1977), for instance. The dianil
compound represented by the general formula (IV) can be readily
synthesized by reacting the diformyl compound of general formula
(III) with aniline hydrochloride.
[Near infrared absorbing material]
The near infrared absorbing material of the present invention may
contain a binder resin in addition to the polymethine compound of
general formula (I).
The near infrared absorbing material may comprise one or more of
various known near infrared absorbing materials in combination with
the polymethine compound of general formula (I) within the limits
beyond which the object of the present invention cannot be
fulfilled.
As the known near infrared absorbers which can be used in
combination, there may be mentioned carbon black, aniline black and
other pigments, the various polymethine dyes (cyanine dyes),
phthalocyanine dyes, dithiol metal complex dyes, naphthoquinone and
anthraquinone dyes, triphenylmethane (-like) dyes, aluminum,
diimmonium dyes, etc. which are described in "Kagaku Kogyo
(Chemical Industry)", May, 1986, pages 45-51 under the title "Near
infrared absorbing dyes" or in the monograph "Development and
Market Trends of Functional Dyes for the Nineties", published by
CMC, 1990, Chapter 2, Paragraphs 2 and 3, and, further, azo dyes,
indoaniline metal complex dyes, intermolecular CT dyes and other
pigments and dyes.
The binder resin is not particularly restricted but includes, among
others, homopolymers and copolymers based on acrylic acid,
methacrylic acid, acrylic esters, methacrylic esters and other
acrylic monomers, methylcellulose, ethylcellulose, cellulose
acetate and other cellulosic polymers, polystyrene, vinyl
chloride-vinyl acetate copolymers, polyvinylpyrrolidone, polyvinyl
butyral, polyvinyl alcohol and other polymers and copolymers of
vinyl compounds, polyesters, polyamides and other condensate
polymers, butadiene-styrene copolymers and other rubber-like
thermoplastic polymers, and polymers obtained by polymerization and
crosslinking of epoxy compounds or other photopolymerizable
compounds.
When the near infrared absorbing material of the present invention
is to be applied to optical recording materials such as optical
cards, such products can be manufactured by applying a solution of
the near infrared absorbing material in an organic solvent to
suitable substrates made of glass or plastics, for instance, by any
of the various techniques so far used or explored, for example by
spin coating. The resin for use in preparing said substrates is not
particularly restricted but includes, among others, acrylic resins,
polyethylene resins, vinyl chloride resins, vinylidene chloride
resins, polycarbonate resins and the like. The solvent to be used
in spin coating is not particularly restricted but includes, among
others, hydrocarbons, halogenated hydrocarbons, ethers, ketones,
alcohols and cellosolves and, among them, alcohols, such as
methanol, ethanol and propanol, and cellosolve solvents, such as
methylcellosolve and ethylcellosolve, are particularly
preferred.
When the near infrared absorbing material of the present invention
is to be applied to near infrared absorbing filters, infrared
blocking materials or films for agricultural use, these can be
produced by admixing the near infrared absorbing material with a
plastic resin, if necessary together with an organic solvent, and
molding the mixture into sheets or films by any of the various
techniques so far explored, for example by injection molding or
casting. The resin to be used is not particularly restricted but
includes, among others, acrylic resins, polyethylene resins, vinyl
chloride resins, vinylidene chloride resins, polycarbonate resins
and the like. The solvent to be used is not particularly restricted
but includes, among others, hydrocarbons, halogenated hydrocarbons,
ethers, ketones, alcohols and cellosolves and, among them,
alcohols, such as methanol, ethanol and propanol, and cellosolve
solvents, such as methylcellosolve and ethylcellosolve, are
particularly preferred.
When the near infrared absorbing material of the present invention
is used in laser thermal transfer recording materials, laser
heat-sensitive recording materials and like recording materials, a
chromogen component or a colorant component, for instance, may be
incorporated in the near infrared absorbing material, or a layer
containing a chromogen component or a colorant component, for
instance, may be provided separately. Usable as the chromogen or
colorant component are those substances capable of forming images
as the result of a physical or chemical change due to heat which
have so far been explored in various ways, for example subliming
dyes or pigments, electron-donating dye precursors combined with an
electron-accepting compound, and polymerizable polymers. Thus, for
example, the colorant component in a laser thermal transfer
recording material is not particularly restricted but includes
inorganic pigments such as titanium dioxide, carbon black, zinc
oxide, Prussian blue, cadmium sulfide, iron oxide, and lead, zinc,
barium and calcium chromates, and organic pigments such as azo,
thioindigo, anthraquinone, anthanthrone, triphenodioxane,
phthalocyanine, quinacridone and other type pigments. As dyes,
there may be mentioned acid dyes, direct dyes, disperse dyes, oil
colors, metal-containing oil colors, and so forth.
The chromogen component for use in a laser heat-sensitive recording
material is not particularly restricted but may be any of those
chromogens conventionally used in heat-sensitive recording
materials. As the electron-donating dye precursors, namely
substances capable of donating an electron or electrons and
accepting a proton or protons from an acid or acids or the like to
thereby develop a color, use may be made of those compounds having
such a partial skeleton as a lactone, lactam, sultone, spiropyran,
ester or amide structure and capable of undergoing ring opening or
cleavage of such partial skeleton upon contact with an
electron-accepting compound. Thus, for example, there may be
mentioned triphenylmethane compounds, fluoran compounds,
phenothiazine compounds, indolylphthalide compounds, lueco auramine
compounds, rhodamine lactam compounds, triphenylmethane compounds,
triazene compounds, spiropyran compounds and fluorene compounds,
among others. As the electron-accepting compound, there may be
mentioned phenolic compounds, organic acids or salts thereof, and
hydroxybenzoic acid esters, among others.
[An original plate for direct plate making]
The polymethine compound of the present invention can be
judiciously used as a near infrared absorbing material in original
plates for direct plate making. The original plates for direct
plate making comprise a light-to-heat conversion layer provided on
a substrate. A silicone rubber layer and/or a protective layer may
be provided on the light-to-heat conversion layer.
The components constituting the light-to-heat conversion layer
include, in addition to the polymethine compound of the present
invention, an image forming component, a binder resin and so forth.
Alternatively, a layer containing an image forming component may be
provided on the light-to-heat conversion layer.
Useful as the image forming component are those substances which
can form images as the result of a physical or chemical change due
to heat and which have so far been explored in various ways. Thus,
for example, there may be mentioned, without any particular
restriction, those containing a microencapsulated heat-fusible
substance and a binder resin, among others, as disclosed in JP
Kokai H03-108588, those containing a blocked isocyanate, among
others, together with an active hydrogen-containing binder on a
substrate having a hydrophilic surface as disclosed in JP Kokai
S62-164049, those containing a microencapsulated lipophilic
component and a hydrophilic binder polymer, among others, as
disclosed in JP Kokai H07-1849, those containing an acid precursor,
a vinyl ether group-containing compound and an alkali-soluble
resin, for instance, as disclosed in JP Kokai H08-220752, those
containing a hydroxy-containing macromolecular compound and an
o-naphthoquinone diazide compound, among others, as disclosed in JP
Kokai H09-5993, those containing nitrocellulose, among others, as
disclosed in JP Kokai H09-131977, and those containing a
polymerization initiator and an ethylenically unsaturated monomer,
oligomer or macromonomer, among others, as disclosed in JP Kokai
H09-14626. Optionally, a silicon rubber layer may be laid on the
light-to-heat conversion layer (photosensitive or heat-sensitive
layer) so that said silicone rubber layer may be subjected to firm
adhesion or peeling off after exposure to thereby form image areas,
as disclosed in JP Kokai H09-80745, JP Kokai H09-131977, JP Kokai
H09-146264 and elsewhere.
The binder resin to be used in the light-to-heat conversion layer
is not particularly restricted but includes, among others,
homopolymers or copolymers of acrylic acid, methacrylic acid,
acrylic esters, methacrylic esters or like acrylic monomers,
methylcellulose, ethylcellulose, cellulose acetate and like
cellulosic polymers, polystyrene, vinyl chloride-vinyl acetate
copolymers, polyvinylpyrrolidone, polyvinyl butyral, polyvinyl
alcohol and like vinyl polymers and copolymers of vinyl compounds,
polyesters, polyamides and like polycondensates, butadiene-styrene
copolymers and like rubber-like thermoplastic polymers, and
polymers obtained by polymerization and crosslinking of epoxy
compounds or like photopolymerizable compounds.
The original plate for plate making as provided by the present
invention should be flexible so that it may be set on a
conventional printing press and, at the same time, it should be
able to endure the pressure applied at the time of printing. Thus,
as the substrate or support member to be used, there may be
mentioned, among others, paper, plastic-laminated (e.g.
polyethylene-, polypropylene, or polystyrene-laminated) paper,
sheets of a metal such as aluminum (inclusive of aluminum alloys),
zinc or copper, films made of a plastic such as cellulose
diacetate, cellulose triacetate, cellulose butyrate, polyethylene
terephthalate, polyethylene, polystyrene, polypropylene,
polycarbonate or polyvinyl acetal, and the like. Typical among them
are coated paper, sheets of a metal such as aluminum, plastic films
such as polyethylene terephthalate films, rubber sheets, and
composite materials produced from such materials. Preferred are
aluminum sheets, aluminum-containing alloy sheets and plastic
films. The substrate has a thickness of 25 .mu.m to 3 mm,
preferably 100 .mu.m to 500 .mu.m.
The original plate for plate making is produced generally by
dissolving or dispersing the polymethine compound, image forming
component, binder resin and other necessary components in an
organic solvent and applying the solution or dispersion to the
substrate.
As the solvent used for said application, there may be mentioned
water, alcohols such as methyl alcohol, isopropyl alcohol, isobutyl
alcohol, cyclopentanol, cyclohexanol and diacetone alcohol,
cellosolves such as methylcellosolve and ethylcellosolve, aromatic
solvents such as toluene, xylene and chlorobenzene, esters such as
ethyl acetate, butyl acetate, isoamyl acetate and methyl
propionate, ketones such as acetone, methyl ethyl ketone, methyl
isobutyl ketone and cyclohexanone, chlorinated hydrocarbons such as
methylene chloride, chloroform and trichloroethylene, ethers such
as tetrahydrofuran and dioxase, and aprotic polar solvents such as
N,N-dimethylformamide and N-methylpyrrolidone.
Between the substrate and light-to-heat conversion layer, there may
be provided a primer layer for the purpose of improving
adhesiveness or printability, or the substrate itself may be
subjected to surface treatment. Thus, for example, a layer of any
of various photosensitive polymers may be cured by exposure to
light prior to providing the light-to-heat conversion layer, as
disclosed in JP Kokai S60-22903, a layer of an epoxy resin may be
heat-cured, as disclosed in JP Kokai S62-50760, a gelatin layer may
be hardened, as disclosed in JP Kokai S63-133151 and, further, a
urethane resin and a silane coupling agent may be used, as
disclosed in JP Kokai H03-200965, or a urethane resin may be used,
as disclosed in JP Kokai H03-273248.
As regards the protective layer for surface protection of the
light-to-heat conversion layer or silicone rubber layer,
transparent films made of polyethylene, polypropylene, polyvinyl
chloride, polyvinylidene chloride, polyvinyl alcohol, polyethylene
terephthalate or cellophane, for instance, may be used for
lamination. Such films may be stretched or oriented prior to
application.
The original plate for direct printing plate making according to
the present invention is tailored to a semiconductor laser having a
certain light emission band. Thus, in order to fabricate a printing
plate using the above original plate, it is irradiated with laser
light using a semiconductor laser having an emission band of
750.about.900 nm, preferably 770.about.850 nm, in accordance with
the known plate-making method to form image and non-image areas
according to digital data from a computer or the like.
EXAMPLES
The following examples illustrate the present invention in further
detail. These examples, however, are by no means limitative of the
scope of the present invention.
Example 1
Polymethine compound [synthesis of compound (11)]
A compound of general formula (II) (R.sub.1=methoxy,
R.sub.2=methoxyethyl, R.sub.3=R.sub.4=methyl, Y=7-methoxy,
Z=ClO.sub.4.sup.-, n=1) (3.79 g), 0.86 g of a compound of general
formula (III) (X=Cl) and 3.36 g of potassium acetate were added to
50 ml of acetic anhydride, and the mixture was stirred at
45.about.50.degree. C. for 60 minutes and then discharged into 300
ml of a 2% aqueous solution of KClO.sub.4. The resulting
crystalline precipitate was collected by filtration, washed with
water and recrystallized from isopropyl alcohol to give 2.95 g of
the compound (11) specifically shown hereinabove.
The elemental analysis data, melting point, absorption maximum
wavelength (.lamda.max) and gram extinction coefficient
(.epsilon.g) of this compound were as follows:
Elemental analysis (C.sub.40H.sub.52Cl.sub.2N.sub.2O.sub.10)
MW=791.8;
TABLE-US-00001 C H N Calcd. (%) 60.68 6.62 3.54; Found (%) 59.96
6.49 3.58.
Melting point (.degree. C.): 152.about.153.degree. C.; .lamda.max:
832 nm (in diacetone alcohol); .epsilon.g: 2.80.times.10.sup.5
ml/gcm.
The IR spectrum of the compound obtained is shown in FIG. 1.
The VIS-NIR absorption spectrum of the compound obtained is shown
in FIG. 9.
Example 2
Polymethine compound [synthesis of compound (12)]
A compound of general formula (II) (R.sub.1=methoxy,
R.sub.2=methoxyethyl, R.sub.3=R.sub.4=methyl, Y=7-methoxy,
Z=I.sup.-, n=1) (4.05 g), 1.80 g of a compound of general formula
(IV) (X=Cl) and 3.36 g of potassium acetate were added to 50 ml of
acetic anhydride, and the mixture was stirred at
45.about.50.degree. C. for 60 minutes and then discharged into 300
ml of a 2% aqueous solution of KI. The resulting crystalline
precipitate was collected by filtration, washed with water and
recrystallized from isopropyl alcohol to give 2.56 g of the
compound (12) specifically shown hereinabove.
The elemental analysis data, melting point, absorption maximum
wavelength (.lamda.max) and gram extinction coefficient
(.epsilon.g) of this compound were as follows:
Elemental analysis (C.sub.40H.sub.52ClIN.sub.2O.sub.6):
MW=819.2;
TABLE-US-00002 C H N Calcd. (%) 58.65 6.40 3.42; Found (%) 58.36
6.43 3.32.
Melting point (.degree. C.): 167.about.168.degree. C.; .lamda.max:
832 nm (in diacetone alcohol); .epsilon.g: 2.65.times.10.sup.5
ml/gcm.
The IR spectrum of the compound obtained is shown in FIG. 2.
Example 3
Polymethine compound [synthesis of compound (13)]
The compound (13) specifically shown hereinabove was obtained in
the same manner as Example 1 except that 3.65 g of the
corresponding compound (II) (R.sub.1=methoxy, R.sub.2=methoxyethyl,
R.sub.3=R.sub.4=methyl, Y=7-methoxy, Z=BF.sub.4.sup.-, n=1) was
used and that 300 ml of a 2% aqueous solution of KBF.sub.4 was used
in lieu of 300 ml of the 2% aqueous solution of KClO.sub.4. The
yield was 2.92 g.
The elemental analysis data, melting point, absorption maximum
wavelength (.lamda.max) and gram extinction coefficient
(.epsilon.g) of this compound were as follows:
Elemental analysis (C.sub.40H.sub.52BClF.sub.4N.sub.2O.sub.6):
MW=779.1;
TABLE-US-00003 C H N Calcd. (%) 61.66 6.73 3.60; Found (%) 61.39
6.75 3.55.
Melting point (.degree. C.): 150.about.152.degree. C.; .lamda.max:
832 nm (in diacetone alcohol); .epsilon.g: 2.85.times.105
ml/gcm.
The IR spectrum of the compound obtained is shown in FIG. 3.
Example 4
Polymethine compound [synthesis of compound (17)]
The compound (17) specifically shown hereinabove was obtained in
the same manner as Example 1 except that 4.06 g of the compound of
formula (II) (R1=methoxy, R.sub.2=R.sub.3=R.sub.4=methyl,
Y=6-methoxy, Z=p-toluenesulfonate, n=1) was used and that 300 ml of
a 2% aqueous solution of p-toluenesulfonic acid was used in lieu of
300 ml of the 2% aqueous solution of KClO.sub.4. The yield was 2.72
g.
The elemental analysis data, melting point, absorption maximum
wavelength (.lamda.max) and gram extinction coefficient
(.epsilon.g) of this compound were as follows:
Elemental analysis (C.sub.43H.sub.51ClN.sub.2O.sub.7S):
MW=775.4;
TABLE-US-00004 C H N Calcd. (%) 66.61 6.63 3.61; Found (%) 65.96
6.72 3.54.
Melting point (.degree. C.): 169.about.171.degree. C.; .lamda.max:
831 nm (in diacetone alcohol); .epsilon.g: 2.60.times.10.sup.5
ml/gcm.
The IR spectrum of the compound obtained is shown in FIG. 4.
Example 5
Polymethine compound [synthesis of compound (19)]
The compound (19) specifically shown hereinabove was obtained in
the same manner as Example 2 except that 3.61 g of the
corresponding compound (II) (R1=methoxy, R.sub.2=methoxyethyl,
R.sub.3=R.sub.4=methyl, Y=7-methoxy, Z=ClO.sub.4.sup.-, n=1) was
used and that 300 ml of a 2% aqueous solution of KClO.sub.4 was
used in lieu of 300 ml of the 2% aqueous solution of KI. The yield
was 3.05 The elemental analysis data, melting point, absorption
maximum wavelength (.lamda.max) and gram extinction coefficient
(.epsilon.g) of this compound were as follows:
Elemental analysis (C.sub.40H.sub.52Cl.sub.2N.sub.2O.sub.8):
MW=759.8;
TABLE-US-00005 C H N Calcd. (%) 63.23 6.90 3.69; Found (%) 62.97
6.85 3.73.
Melting point (.degree. C.): 197.about.198.degree. C.; .lamda.max:
822 nm (in diacetone alcohol); .epsilon.g: 3.12.times.10.sup.5
ml/gcm.
The IR spectrum of the compound obtained is shown in FIG. 5.
The VIS-NIR absorption spectrum of the compound obtained is shown
in FIG. 10.
Example 6
Polymethine compound [synthesis of compound (47)]
The compound (47) specifically shown hereinabove was obtained in
the same manner as Example 1 except that 4.34 g of the compound of
formula (II) (R.sub.1=methoxy, R.sub.2=methoxyethyl,
R.sub.3=R.sub.4=methyl, Y=7-methoxy, Z=p-toluenesulfonate, n=1) was
used and that 300 ml of a 2% aqueous solution of p-toluenesulfonic
acid was used in lieu of 300 ml of the 2% aqueous solution of
KClO.sub.4. The yield was 2.70 g.
The elemental analysis data, melting point, absorption maximum
wavelength (.lamda.max) and gram extinction coefficient
(.epsilon.g) of this compound were as follows:
Elemental analysis (C.sub.47H.sub.59ClN.sub.2O.sub.7S):
MW=831.5;
TABLE-US-00006 C H N Calcd. (%) 67.89 7.15 3.37; Found (%) 67.20
7.24 3.45.
Melting point (.degree. C.): 205.about.207.degree. C.; .lamda.max:
822 nm (in diacetone alcohol); .epsilon.g: 2.80.times.105
ml/gcm.
The IR spectrum of the compound obtained is shown in FIG. 6.
Example 7
Polymethine compound [synthesis of compound (51)]
A compound of general formula (II) (R.sub.1=methoxy,
R.sub.2=3-sulfopropyl, R.sub.3=R.sub.4=methyl, Y=7-methyl, n=0)
(3.25 g), 1.80 g of a compound of general formula (IV) (X=Cl) and
3.36 g of potassium acetate were added to 50 ml of acetic
anhydride, and the mixture was stirred at 65.about.70.degree. C.
for 60 minutes. Then, 200 ml of isopropyl alcohol was added and the
resulting mixture was further stirred at the same temperature for
60 minutes. After evaporation to dryness, 100 ml of ethyl acetate
was added, and the mixture was stirred at room temperature for an
hour. The resulting crystalline precipitate was collected by
filtration, washed with 10 ml of ethyl acetate and recrystallized
from 100 ml of methanol. The crystals obtained were dissolved in a
solution composed of 2 g of sodium acetate, 100 ml of methanol and
100 ml of isopropyl alcohol, and the solvents were distilled off at
ordinary pressure. The resulting crystalline precipitate was
collected by filtration and dried to give 2.30 g of the compound
(51) specifically shown hereinabove.
The elemental analysis data, absorption maximum wavelength
(.lamda.max) and gram extinction coefficient (.epsilon.g) of this
compound were as follows:
Elemental analysis (C.sub.40H.sub.50ClN.sub.2NaO.sub.8S.sub.2):
MW=809.4;
TABLE-US-00007 C H N Calcd. (%) 59.36 6.23 3.46; Found (%) 58.69
6.37 3.37.
Melting point (.degree. C.): 260.about.261.degree. C. (decomp.);
.lamda.max: 824 nm (in diacetone alcohol); .epsilon.g:
2.82.times.10.sup.5 ml/gcm.
The IR spectrum of the compound obtained is shown in FIG. 7.
The VIS-NIR absorption spectrum of the compound obtained is shown
in FIG. 11.
Example 8
Polymethine compound [synthesis of compound (55)]
The compound (55) specifically shown hereinabove was obtained in
the same manner as Example 2 except that 3.62 g of the
corresponding compound (II) (R.sub.1=methoxy, R.sub.2=methoxyethyl,
R.sub.3=R.sub.4=methyl, Y=7-methoxy, Z=BF.sub.4.sup.-, n=1) was
used and that 300 ml of a 2% aqueous solution of KBF.sub.4 was used
in lieu of 300 ml of the 2% aqueous solution of KI. The yield was
2.20 g.
The elemental analysis data, melting point, absorption maximum
wavelength (.lamda.max) and gram extinction coefficient
(.epsilon.g) of this compound were as follows:
Elemental analysis (C.sub.40H.sub.52BClF.sub.4N.sub.2O.sub.4):
MW=747.1;
TABLE-US-00008 C H N Calcd. (%) 64.30 7.02 3.75; Found (%) 64.21
6.91 3.70.
Melting point (.degree. C.): 198.about.199.degree. C.; .lamda.max:
822 nm (in diacetone alcohol); .epsilon.g: 3.20.times.105
ml/gcm.
The IR spectrum of the compound obtained is shown in FIG. 6.
Example 9
Polymethine compound [preparation of amorphous form of compound
(55)]
The compound (55) obtained in Example 8 (2.0 g) was dissolved in 20
ml of acetone and the solution was concentrated and dried to give
1.95 g of the amorphous form of compound (55).
The elemental analysis data, melting point, absorption maximum
wavelength (.lamda.max) and gram extinction coefficient
(.epsilon.g) of this compound were as follows:
Elemental analysis (C.sub.40H.sub.52BCF.sub.4N.sub.2O.sub.4):
MW=747.1;
TABLE-US-00009 C H N Calcd. (%) 64.30 7.02 3.75; Found (%) 64.24
6.99 3.69.
Melting point (.degree. C.): indefinite; .lamda.max: 822 nm (in
diacetone alcohol); .epsilon.g: 3.18.times.20.sup.5 ml/gcm.
The powder X-ray diffraction pattern is shown in FIG. 12.
Example 10
Polymethine compound [preparation of the .beta.-crystal form of
compound (55)]
The compound (55) obtained in Example 8 (2.0 g) was recrystallized
from 30 ml of methanol to give 1.42 g of the .beta.-crystal of
compound (55).
The elemental analysis data, melting point, absorption maximum
wavelength (.lamda.max) and gram extinction coefficient
(.epsilon.g) of this compound were as follows:
Elemental analysis (C.sub.40H.sub.52BClF.sub.4N.sub.2O.sub.4):
MW=747.1;
TABLE-US-00010 C H N Calcd. (%) 64.30 7.02 3.75; Found (%) 64.25
6.96 3.71.
Melting point (.degree. C.): 204.about.206.degree. C.; .lamda.max:
822 nm (in diacetone alcohol); .epsilon.g: 3.21.times.105
ml/gcm.
The powder X-ray diffraction pattern is shown in FIG. 13.
Example 11
Polymethine compound [preparation of the crystalline methanol
adduct of compound (55)]
The compound (55) obtained in Example 8 (2.0 g) was dissolved in 50
ml of methanol, and using an evaporator, the solution was
concentrated under reduced pressure to 7 g. After cooling, this
residue was recovered by filtration and dried to give 1.92 of the
crystalline methanol adduct of compound (55).
The melting point, absorption maximum wavelength (.lamda.max) and
gram extinction coefficient (.epsilon.g) of this compound were as
follows:
Melting point (.degree. C.): .about.180.degree. C.; .lamda.max: 822
nm (in diacetone alcohol); .epsilon.g: 2.92.times.10.sup.5
ml/gcm.
The powder X-ray diffraction pattern is shown in FIG. 14.
Example 12
Polymethine compound [preparation of the .alpha.-crystal form of
compound (55)]
The amorphous form of compound (55) obtained in Example 9 (1.5 g)
was dispersed in 20 ml of methanol at room temperature to give 1.23
g of the a-crystal of compound (55).
The elemental analysis data, melting point, absorption maximum
wavelength (.lamda.max) and gram extinction coefficient
(.epsilon.g) of this compound were as follows:
Elemental analysis (C.sub.40H.sub.52BClF.sub.4N.sub.2O.sub.4):
MW=747.1;
TABLE-US-00011 C H N Calcd. (%) 64.30 7.02 3.75; Found (%) 64.21
6.93 3.71.
Melting point (.degree. C.): 195.about.197.degree. C.; .lamda.max:
822 nm (in diacetone alcohol); .epsilon.g: 3.20.times.105
ml/gcm.
The powder X-ray diffraction pattern is shown in FIG. 15.
[Maximum absorption wavelength]
The maximum absorption wavelength (.lamda.max) of the polymethine
compound of the present invention in diacetone alcohol as well as
those of known Compound A and Compound B were measured. The results
are shown in Table 1.
TABLE-US-00012 TABLE 1 .lamda.max Compound (11) 832 nm Compound
(12) 832 nm Compound (13) 832 nm Compound (17) 831 nm Compound (19)
822 nm Compound (47) 822 nm Compound (51) 824 nm Compound (55) 822
nm Compound A 788 nm Compound B 812 nm
[Solubility Test]
The solubility of the polymethine compound of the invention in
methyl ethyl ketone as well as the solubilities of said known
Compound A and Compound B were measured. Solubility measurements
were carried out by the following method.
Method:
A 5 ml screw tube was charged with 200 mg of each polymethine
compound and 1 ml of methyl ethyl ketone and agitated for
dissolution with Mix-Rotor at 25.degree. C. overnight. Each sample
was visually inspected for insoluble matter. When no insoluble
residue was found, the solubility was rated .gtoreq.20%. When an
insoluble residue was found, the solubility was rated less than
20%.
Except that each polymethine compound was used in the amounts of
150 mg, 100 mg, 50 mg, 30 mg and 10 mg instead of 200 mg, the above
procedure was repeated and solubility measurements were made in the
same manner. The results are shown in Table 2.
TABLE-US-00013 TABLE 2 Solubility (g/ml) Compound (11) .gtoreq.20%
Compound (12) .gtoreq.10%, .gtoreq.15% Compound (13) .gtoreq.20%
Compound (19) .gtoreq.20% Compound (47) .gtoreq.20% Compound (55)
.gtoreq.20% Compound A .gtoreq.3%, .gtoreq.5% Compound B
.gtoreq.1%, .gtoreq.3%
As the compound (55) in Tables 1 and 2, the compound synthesized in
Example 8 was used for measurement.
Example 13
Production of a Near Infrared Absorbing Material
A sample was produced by applying, to a polyethylene terephthalate
(PET) film having an average thickness of 5 .mu.m, a solution of 10
g of Delpet SON (acrylic resin; product of Asahi Chemical Industry;
as a binder) and 0.2 g of the above compound (11) in 90 g of a
toluene-methyl ethyl ketone (1/1) mixture using a wire bar to give
a dry film thickness of about 5 .mu.m.
Laser beams from a single mode semiconductor laser (wavelength: 830
nm) were converged by means of a lens so that a beam diameter of 10
.mu.m might be attained on the surface of said sample. The
semiconductor was adjusted so that the power of the laser beam
arriving at said surface might be varied within the range of 50 to
200 mW. The sample was thus irradiated with a single pulse at a
pulse width of 20 .mu.s. After completion of the irradiation, the
sample was observed under the light microscope. When the laser
power arriving at the surface was 50 mW, through hole formation
with a diameter of about 10 .mu.m was confirmed.
Example 14
Production of a Near Infrared absorbing Material
The procedure of Example 13 was followed in the same manner except
that 0.2 g of the compound (19) was used in lieu of 0.2 g of the
compound (11). The sample after completion of the irradiation was
examined under an optical microscope, whereupon through hole
formation with a diameter of about 10 .mu.m was confirmed when the
laser power arriving at the surface was 50 mW.
Example 15
Making of an Original Plate for direct Printing Plate Making
(Formation of an undercoat layer)
On a polyethylene terephthalate film having a thickness of 175
.mu.m, there was formed a gelatin layer as a primer layer so that
the dry film thickness of said gelatin layer amounted to 0.2
.mu.m.
(Formation of a light-to-heat conversion layer)
A light-to-heat conversion layer was formed by applying a coating
composition prepared in accordance with the recipe given below to
the above gelatin-coated polyethylene terephthalate film to a dry
film thickness of 2 .mu.m.
TABLE-US-00014 Compound No. (11) 0.1 weight part Crisvon 3006LV
(polyurethane; 5.0 weight parts Product of Dainippon Ink and
Chemicals) Solsperse S27000 (product of ICI) 0.4 weight part
Nitrocellulose (containing 30% of 4.2 weight parts n-propanol)
Xylylenediamine (1 mole)-glycidyl 2.0 weight parts methacrylate (4
moles) adduct Ethyl Michler's ketone 0.2 weight part
Tetrahydrofuran 90 weight parts (Formation of a silicone rubber
layer)
A silicone rubber layer was formed on the above light- to-heat
conversion layer by applying thereto a coating composition prepared
in accordance with the recipe given below to a dry film thickness
of 2 .mu.m.
TABLE-US-00015 .alpha.,.omega.-Divinylpolydimethylsiloxane 9.0
weight parts (degree of polymerization: ca 700)
(CH.sub.3).sub.3Si--O--(SiH(CH.sub.3)--O).sub.n--Si(CH.sub.3).sub.3
0.6 we- ight part Polydimethylsiloxane (degree of 0.5 weight part
polymerization: ca 8,000) Olefin-chloroplatinic acid 0.08 weight
part Inhibitor HC.ident.C--C(CH.sub.3).sub.2--O--Si(CH.sub.3).sub.3
0.07 weight part Isopar-G (product of Esso Chemical) 55 weight
parts
Writing was made on the plate obtained in the above manner, using a
semiconductor laser with an oscillation wavelength of 830 nm and a
beam diameter of 10 .mu.m. The power on the plate was 110 mW. A
printing plate with sharp edges could be produced; the laser
recording sensitivity was 200 mJ/cm.sup.2 and the resolution was 8
.mu.m.
Example 16
Making of an Original Plate for Direct Printing Plate Making
A plate for direct printing plate making was produced in the same
manner as in Example 11 except that, in Example 15, 0.1 weight part
of the compound (47) was used in lieu of 0.1 weight part of the
compound (11).
Writing was made on the plate obtained in the above manner, using a
semiconductor laser with an oscillation wavelength of 830 nm and a
beam diameter of 10 .mu.m. The power on the plate was 110 mW. A
printing plate with sharp edges could be produced; the laser
recording sensitivity was 200 mJ/cm.sup.2 and the resolution was 8
.mu.m.
Example 17
Making of an Original Plate for Direct Printing Plate Making
A plate for direct printing plating making was manufactured in the
same manner as Example 11 except that, in Example 15, 0.1 weight
part of the compound (55) in Table 1 was used in lieu of 0.1 weight
part of the compound (11).
Writing was made on the plate obtained in the above manner, using a
semiconductor laser with an oscillation wavelength of 830 nm and a
beam diameter of 10 .mu.m. The power on the plate was 110 mW. A
printing plate with sharp edges could be produced; the laser
recording sensitivity was 200 mJ/cm.sup.2 and the resolution was 8
.mu.m.
Comparative Example 1
The procedure of Example 13 was repeated except that 0.2 g of the
polymethine compound having the structural formula shown below,
which is described in JP Kokai S63-319191, was used in lieu of 0.2
g of the compound (11). In a light microscopic examination of the
sample after completion of the irradiation, no through hole
formation was observed even when the laser power arriving at the
surface was 100 mW. ##STR00028##
Comparative Example 2
Except that, in Example 13, 0.2 g of the polymethine compound of
the following chemical formula as described in Journal of Organic
Chemistry 60, 2392, Table 1 was used in lieu of 0.2 g of the
compound (11), the procedure described in Example 13 was repeated.
In a light microscopic examination of the sample after completion
of the irradiation, no through hole formation was observed even
when the laser power arriving at the surface was 50 mW.
##STR00029##
EFFECTS OF THE INVENTION
The polymethine compound of general formula (I) shows less
absorption in the visible region, and the near infrared absorbing
material comprising this compound can be used with advantage in
laser thermal transfer recording materials and laser heat-sensitive
recording materials having good sensitivity to laser light with a
high light-to-heat conversion efficiency and, therefore, enabling
high-speed recording for high-density, high-quality records. The
polymethine compound of general formula (I) is quite highly soluble
in various solvents used for making the light-to-heat conversion
layer of original plates for direct printing plate making and has
good compatibility with various binder resins and other components,
facilitating preparation of coating compositions. It can thus form
uniform light-to-heat conversion layers and is particularly suited
for use in the manufacture of original plates for direct printing
plate making.
* * * * *