U.S. patent application number 10/054766 was filed with the patent office on 2003-07-10 for two-layer imageable composition including non-volatile acid in bottom layer.
This patent application is currently assigned to KODAK POLYCHROME GRAPHICS, L.L.C.. Invention is credited to Haley, Neil, Kalamen, John.
Application Number | 20030129526 10/054766 |
Document ID | / |
Family ID | 25464650 |
Filed Date | 2003-07-10 |
United States Patent
Application |
20030129526 |
Kind Code |
A1 |
Haley, Neil ; et
al. |
July 10, 2003 |
Two-layer imageable composition including non-volatile acid in
bottom layer
Abstract
The present invention provides an imageable composition, which
includes a bottom layer including a first strong, non-volatile acid
having a pKa of not more than about 8 and coated thereon a top
layer including an acid curable composition, an acid generator, an
infrared absorber and optionally a colorant. The present invention
further provides an imageable element, which includes a substrate
and an imageable composition according to the present invention
coated on a surface of the substrate. Also provided is method of
producing an imaged element according to the present invention.
Inventors: |
Haley, Neil; (Wellington,
CO) ; Kalamen, John; (Loveland, CO) |
Correspondence
Address: |
VAZKEN ALEXANIAN
OHLANDT, GREELEY, RUGGIERO & PERLE, L.L.P.
10th FLOOR
ONE LANDMARK SQUARE
STAMFORD
CT
06901-2682
US
|
Assignee: |
KODAK POLYCHROME GRAPHICS,
L.L.C.
NORWALK
CT
|
Family ID: |
25464650 |
Appl. No.: |
10/054766 |
Filed: |
January 22, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10054766 |
Jan 22, 2002 |
|
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09933884 |
Aug 21, 2001 |
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Current U.S.
Class: |
430/176 ;
430/163; 430/270.1; 430/325; 430/330; 430/926; 430/944 |
Current CPC
Class: |
G03F 7/016 20130101;
B41C 2210/10 20130101; B41C 1/1016 20130101; B41C 2210/14 20130101;
B41C 2210/24 20130101; B41C 2210/262 20130101; G03F 7/0045
20130101; B41C 2210/22 20130101; B41C 2210/06 20130101; G03F 7/021
20130101; B41C 2210/26 20130101; B41C 1/1008 20130101; B41C 2210/04
20130101; G03F 7/0382 20130101 |
Class at
Publication: |
430/176 ;
430/163; 430/325; 430/330; 430/926; 430/944; 430/270.1 |
International
Class: |
G03F 007/021; G03F
007/30 |
Claims
What is claimed is:
1. An imageable composition comprising: a bottom layer comprising a
first strong, non-volatile acid having a pKa of not more than about
8; and coated thereon a top layer comprising an acid curable
composition, an acid generator, an infrared absorber and optionally
a colorant.
2. The composition of claim 1, wherein said first strong,
non-volatile acid has a pKa of not more than about 4.
3. The composition of claim 2, wherein said strong non-volatile
acid is a sulfonic acid represented by the
formula:R--SO.sub.3Hwherein R is selected from the group consisting
of: a substituted or unsubstituted hydrocarbyl of 1 to 22 carbon
atoms, a substituted or unsubstituted aryl of 6 to 22 carbon atoms
and a mixture thereof.
4. The composition of claim 3, wherein R is selected from the group
consisting of: linear, branched or cyclic alkyl of 1 to 22 carbon
atom, linear, branched or cyclic haloalkyl of 1 to 22 carbon atom
having at least one halogen and a mixture thereof.
5. The composition of claim 3, wherein said sulfonic acid is an
aryl sulfonic acid represented by the formula: 16wherein each of
R.sup.1, R.sup.2, R.sup.3, R.sup.4 and R.sup.5 is independently
selected from the group consisting of: hydrogen, alkyl of 1 to 12
carbon atoms, haloalkyl of 1 to 22 carbon atoms having at least one
halogen, aryl of 6 to 12 carbon atoms, halogen, hydroxy, alkoxy,
cyano, nitro, alkoxycarbonyl and acyl.
6. The composition of claim 5, wherein said acyl is represented by
the formula: 17wherein R.sup.6 is selected from the group
consisting of: hydrogen, alkyl of 1 to 12 carbon atoms, haloalkyl
of 1 to 12 carbon atoms having at least one halogen, alkoxy, cyano,
nitro, alkoxycarbonyl and acetyl
7. The composition of claim 5, wherein said aryl sulfonic acid is
represented by the formula: 18wherein each of R.sup.1, R.sup.4 and
R.sup.6 is independently selected from the group consisting of:
hydrogen, alkyl of 1 to 12 carbon atoms, haloalkyl of 1 to 12
carbon atoms having at least one halogen, aryl of 6 to 12 carbon
atoms, halogen, hydroxy, alkoxy, cyano, nitro, alkoxycarbonyl and
acyl and wherein R.sup.7 is selected from the group consisting of:
hydrogen, alkyl of 1 to 12 carbon atoms, haloalkyl of 1 to 12
carbon atoms having at least one halogen, aryl of 6 to 12 carbon
atoms, alkoxycarbonyl and acyl.
8. The composition of claim 7, wherein said aryl sulfonic acid is
3-benzoyl-4-hydroxy-6-methoxybenzenesulfonic acid.
9. The composition of claim 1, wherein said acid curable
composition comprises: a binder; and a crosslinking agent for said
binder.
10. The composition of claim 9, wherein said binder comprises a
polymer having at least two reactive groups each independently
selected from the group consisting of: hydroxy, carboxylic acid,
amine, carbamate, amide, sulfonamide and imide.
11. The composition of claim 10, wherein said reactive group in
said polymer is a hydroxy group.
12. The composition of claim 11, wherein said polymer is selected
from the group consisting of: a polyol, a polyether polyol, a
novolak resin, a resole resin, a hydroxyfunctional acrylic resin, a
hydroxyfunctional polyester resin and combination thereof.
13. The composition of claim 9, wherein said binder is a novolak
resin.
14. The composition of claim 9, wherein said crosslinking agent is
selected from the group consisting of: a resole resin, an amino
resin, an amido resin, an epoxy compound having at least two
epoxide groups and a combination thereof.
15. The composition of claim 14, wherein said crosslinking agent is
resole resin.
16. The composition of claim 14, wherein said binder is a novolak
resin.
17. The composition of claim 14, wherein said crosslinking agent is
an amino resin having at least two alkoxymethyl groups.
18. The composition of claim 17, wherein said amino resin is
selected from the group consisting of: an alkoxymethylated melamine
resin, an alkoxymethylated benzoguanamine resin, an
alkoxymethylated glycoluril, an alkoxymethylated polyacrylamid, an
alkoxymethylated polymethacrylamid and a combination thereof.
19. The composition of claim 18, wherein said amino resin is an
alkoxymethylated melamine resin having from about 2 to about 6
methoxymethyl groups.
20. The composition of claim 9, further comprising an isocyanate
crosslinker having at least two isocyanate groups.
21. The composition of claim 1, wherein said bottom layer further
comprises a binder selected from the group consisting of: a novolak
resin, a resole resin, an amino resin, an epoxy resin, a
polyurethane resin, a polyacetal resin and a combination
thereof.
22. The composition of claim 8, wherein said acid generator is an
ultraviolet, visible or infrared radiation or heat activated
compound.
23. The composition of claim 22, wherein said an acid generator is
selected from the group consisting of: an onium salt, a covalently
bound sulfonate group containing compound,
hydrocarbylsulfonamido-N-hydrocarbyl sulfonate and a combination
thereof.
24. The composition of claim 23, wherein said acid generator is an
onium salt.
25. The composition of claim 24, wherein said onium salt has a
non-nucleophilic counter anion selected from the group consisting
of: tetrafluoroborate, hexafluorophosphate, hexafluoroarsenate,
hexafluoroantimonate, tetrakis(pentafluorophenyl)borate, triflate,
pentafluoropropionate, pentafluoroethanesulfonate,
benzenesulfonate, p-methylbenzenesulfonate and
pentafluorobenzenesulfonate.
26. The composition of claim 24, wherein said onium salt is
selected from the group consisting of: an iodonium salt, a
sulfonium salt, a hydrocarbyloxysulfonium salt, a
hydrocarbyloxyammonium salt, an aryl diazonium salt and a
combination thereof.
27. The composition of claim 26, wherein said
hydrocarbyloxyammonium salt is a salt of an N-hydrocarbyloxy
substituted nitrogen containing heterocyclic compound.
28. The composition of claim 27 wherein said N-hydrocarbyloxy
substituted nitrogen containing heterocyclic compound is
N-ethoxyisoquinolinium hexafluorophosphate.
29. The composition of claim 26, wherein said iodonium salt is
4-octyloxyphenyl phenyliodonium hexafluoroantimonate.
30. The composition of claim 26, wherein said acid generator is a
monomeric or oligomeric aromatic diazonium salt.
31. The composition of claim 30, wherein said diazonium salt has a
counter anion other than a halide.
32. The composition of claim 31, wherein said counter anion is
selected from the group consisting of: sulfate, bisulfate,
tetrafluoroborate, hexafluorophosphate, hexafluoroarsenate,
hexafluoroantimonate, tetrakis(pentafluorophenyl)borate, triflate,
pentafluoropropionate, pentafluoroethanesulfonate,
benzenesulfonate, p-methylbenzenesulfonate and
pentafluorobenzenesulfonate.
33. The composition of claim 30, wherein said diazonium salt is
selected from the group consisting of:
2-methoxy-4-phenylaminobenzene diazonium hexafluorophosphate
represented by the formula: 192-methoxy-4-phenylamin-
obenzenediazonium p-toluenesulfonate represented by the formula: 20
an oligomeric diazonium salt selected from the group consisting of
compounds represented by the formula: 21 wherein n is from 1 to 11;
and a combination of any of the aforementioned compounds.
34. The composition of claim 1, wherein said acid curable
composition further comprises a second strong, non-volatile acid
having a pKa of not more than about 8.
35. The composition of claim 34, wherein said second strong,
non-volatile acid has a pKa of not more than about 4.
36. The composition of claim 35, wherein said strong non-volatile
acid is a sulfonic acid represented by the
formula:R---O.sub.3Hwherein R is selected from the group consisting
of: a substituted or unsubstituted hydrocarbyl of 1 to 22 carbon
atoms, a substituted or unsubstituted aryl of 6 to 22 carbon atoms
and a mixture thereof.
37. The composition of claim 36, wherein R is selected from the
group consisting of: linear, branched or cyclic alkyl of 1 to 22
carbon atom, linear, branched or cyclic haloalkyl of 1 to 22 carbon
atom having at least one halogen and a mixture thereof.
38. The composition of claim 36, wherein said sulfonic acid is an
aryl sulfonic acid represented by the formula: 22wherein each of
R.sup.1, R.sup.2, R.sup.3, R.sup.4 and R.sup.5 is independently
selected from the group consisting of: hydrogen, alkyl of 1 to 12
carbon atoms, haloalkyl of 1 to 22 carbon atoms having at least one
halogen, aryl of 6 to 12 carbon atoms, halogen, hydroxy, alkoxy,
cyano, nitro, alkoxycarbonyl and acyl.
39. The composition of claim 38, wherein said acyl is represented
by the formula: 23wherein R.sup.6 is selected from the group
consisting of: hydrogen, alkyl of 1 to 12 carbon atoms, haloalkyl
of 1 to 12 carbon atoms having at least one halogen, alkoxy, cyano,
nitro, alkoxycarbonyl and acetyl
40. The composition of claim 38, wherein said aryl sulfonic acid is
represented by the formula: 24wherein each of R.sup.1, R.sup.4 and
R.sup.6 is independently selected from the group consisting of:
hydrogen, alkyl of 1 to 12 carbon atoms, haloalkyl of 1 to 12
carbon atoms having at least one halogen, aryl of 6 to 12 carbon
atoms, halogen, hydroxy, alkoxy, cyano, nitro, alkoxycarbonyl and
acyl and wherein R.sup.7 is selected from the group consisting of:
hydrogen, alkyl of 1 to 12 carbon atoms, haloalkyl of 1 to 12
carbon atoms having at least one halogen, aryl of 6 to 12 carbon
atoms, alkoxycarbonyl and acyl.
41. The composition of claim 40, wherein said aryl sulfonic acid is
3-benzoyl-4-hydroxy-6-methoxybenzenesulfonic acid.
42. The composition of claim 34, wherein said first and said second
strong, non-volatile acids are the same.
43. The composition of claim 34, wherein said first and said second
strong, non-volatile acids are different acids.
44. The composition of claim 1, further comprising a photothermal
converter material.
45. The composition of claim 1, wherein said counter anion of said
infrared absorber is the conjugate base of a non-volatile acid.
46. The composition of claim 45, wherein said non-volatile acid has
a counter anion other than a halide.
47. The composition of claim 46, wherein said counter anion is
selected from the group consisting of: sulfate, bisulfate,
tetrafluoroborate, hexafluorophosphate, hexafluoroarsenate,
hexafluoroantimonate, tetrakis(pentafluorophenyl)borate, triflate,
pentafluoropropionate, pentafluoroethanesulfonate,
benzenesulfonate, p-methylbenzenesulfonate and
pentafluorobenzenesulfonate.
48. The composition of claim 1, wherein said infrared absorber is
selected from the group consisting of: a pigment, a dye and a
combination thereof.
49. The composition of claim 48, wherein said infrared absorber is
a pigment selected from the group consisting of: black pigments,
yellow pigments, orange pigments, brown pigments, red pigments,
purple pigments, blue pigments, green pigments, fluorescent
pigments, metal powder pigments, polymer bond pigments, insoluble
azo pigments, azo lake pigments, condensation azo pigments, chelate
azo pigment, phthalocyanine pigments, anthraquinone pigments,
perylene pigments, perynone pigments, thioindigo pigments,
quinacridone pigments, dioxazine pigments, isoindolinone pigments,
quinophthalone pigments, colored lake pigments, azine pigments,
nitroso pigments, nitro pigments, natural pigments, fluorescent
pigments, inorganic pigments, carbon black, Paris Blue, Prussian
Blue and a combination thereof.
50. The composition of claim 48, wherein said infrared absorber is
a dye selected from the group consisting of: cyanine dyes,
squarylium dyes, pyrylium salts and nickel thiolate complexes.
51. The composition of claim 1, wherein said colorant is selected
from the group consisting of a colorant dye, a colorant pigment and
a combination thereof.
52. The composition of claim 1, wherein said colorant dye is a blue
colorant dye represented by the formula: 25
53. The composition of claim 1, wherein at least one of said
infrared absorber and said colorant has a counter anion derived
from a non-volatile acid.
54. An imageable element comprising: a substrate; and an imageable
composition coated on a surface of said substrate, said imageable
composition comprising: a bottom layer comprising a first strong,
non-volatile acid having a pKa of not more than about 8; and coated
thereon a top layer comprising an acid curable composition, an acid
generator, an infrared absorber and optionally a colorant.
55. The imageable element of claim 54, wherein said imageable
composition comprises a photothermal converting material.
56. A method of producing an imaged element comprising the steps
of: providing an imageable element comprising a substrate and an
imageable composition coated on a surface of said substrate, said
imageable composition comprising: a bottom layer comprising a first
strong, non-volatile acid having a pKa of not more than about 8,
and coated thereon a top layer comprising an acid curable
composition, an acid generator, an infrared absorber and optionally
a colorant; imagewise exposing said imageable element to radiation
to produce an imagewise exposed element having exposed and
unexposed regions; baking said imagewise exposed element at a
temperature and period of time sufficient to produce a cured
element; and contacting said cured element and a developer to
remove the unexposed regions and thereby produce said imaged
element.
57. The method of claim 56, wherein said exposing step is carried
out using an infrared laser.
Description
[0001] This application is a Continuation-In-Part and claims
priority from U.S. application Ser. No. 09/933,884, filed Aug. 21,
2001.
BACKGROUND OF THE INVENTION
[0002] 1. FIELD OF THE INVENTION
[0003] The present invention relates to an imageable composition,
which includes a bottom layer including a first strong,
non-volatile acid and coated thereon a top layer including an acid
curable composition, an acid generator and an infrared absorber.
Preferably, at least one of infrared absorber and colorant has a
counter anion derived from a non-volatile acid. More particularly,
the present invention relates to a thermally imageable composition
in which the top layer further includes a second strong,
non-volatile acid.
[0004] 2. DESCRIPTION OF THE PRIOR ART
[0005] Printing plates having a coating of a thermally imageable
composition that includes an acid curable composition and either a
"free acid" cure catalyst or a "latent acid" cure catalyst, such
as, an acid generator, are known. However, each of these systems
suffers from disadvantages, which include difficulty of controlling
the cure rates.
[0006] The difficulty of controlling cure rates becomes even more
acute if the one or more ingredients of the thermally imageable
composition have counter anions that are derived from a volatile
acid. Thus, if an ingredient of the thermally imageable composition
has a counter anion, such as, a halide ion derived from a volatile
acid, the halide ion is converted to the volatile acid by combining
with a proton under the strongly acidic cure conditions to produce
the non-volatile acid. The volatile acid, for example, HF, HCl, HBr
or Hl, would then be easily volatilized and lost under the
conditions of thermal imaging and subsequent baking, thereby
reducing the cure rate. If a "latent acid" cure catalyst having a
counter anion derived from a volatile acid is used, the cure rate
would also be reduced to unacceptably low levels because of the
loss of the volatile acid under the conditions of thermal imaging
and subsequent baking.
[0007] U.S. Pat. No. 5,965,319 and Japanese Patent Application JP
10-039,509 describe a negatively working composition having an IR
absorber, novolak and resole resins, and an iodonium, sulfonium or
diazonium salt, with a sulfonate group as counter ion. There is no
teaching that the presence of a "subbing" layer of a strong,
non-volatile acid, such as, a sulfonic acid, as a discrete additive
or the presence of a dye having a counter anion derived from a
non-volatile acid, such as, D11 dye, will improve cure rate and
processing latitude.
[0008] U.S. Pat. No. 6,042,987 describes a thermal negative system
in which an acid is produced from a typical generator upon exposure
to IR radiation. This promotes cross-linking between a novolak and
a crosslinking species.
[0009] Japanese Patent Application JP 11-268,438 describes a
thermal positive plate having a novolak resin and an IR absorber
that has a thermally decomposable sulfonate directly attached
thereto. At unimaged regions of the plate, the absorber acts as an
insolubiliser and, at imaged areas, it acts as a dissolution
accelerant. Japanese Patent Application JP 10-193,554 describes a
negative plate having excellent run length by virtue of a new,
improved polymer. Japanese Patent Application JP 3-291,665
discloses conventionally imaged negative plate systems. There is no
disclosure that the presence of a "subbing" layer of a strong,
non-volatile acid, or the presence of a strong, non-volatile acid
as a discrete additive or the presence of a dye having a counter
anion derived from a non-volatile acid, such as, D11 dye, which has
counter anions that combine with protons to produce non-volatile
acids, will improve cure rate and processing latitude.
[0010] U.S. Pat. Nos. 5,340,699 and 5,919,601 describe imageable
compositions having a binder, a crosslinker, an acid generator and
an infrared absorber. These patents do not describe the use of a
strong acid in addition to the acid generator, or the presence of a
"subbing" layer of a strong, non-volatile acid, or that added
sulfonic acids would improve plate speed or processing latitude.
Further, even though an IR dye having a p-toluene sulfonate anion
is disclosed, it is not disclosed that this anion will improve
plate speed or processing latitude by combining with a proton to
produce a non-volatile acid.
[0011] U.S. Pat. No. 5,641,608 describes ablative and
positive/negative solubility differential systems for PCB
precursors. The negative systems rely on adding an amine active
ingredient just prior to use, or by employing a "UV flood then IR
exposure" process. U.S. Pat. No. 5,763,134 describes a composition
having an acid generator, typically a triazine, and a squarylium
dye having a defined nucleus. European Patent Application EP
632,003 describes MeO-- and Me- containing phenol compounds for use
as improved heat curing additives in conventional positive
plates.
[0012] None of the above disclosures teach or suggest that the
presence of a a strong, non-volatile acid, the presence of a
"subbing" layer including a strong, non-volatile acid, such as, a
sulfonic acid, and/or the presence of dyes, such as, D11 dye, which
has counter anions that combine with protons to produce
non-volatile acids, will improve cure rate and processing latitude
when included in the composition.
[0013] Accordingly, it is an object of the present invention to
improve the speed and processing latitude and robustness of
thermal, pre-heated, negative working patterning compositions,
especially printing plates, while maintaining adequate shelf
life.
[0014] It is another object of the present invention to improve the
formulating scope of negative working imageable compositions.
[0015] It is still another object of the present invention to
improve speed and fog control of such compositions without having a
deleterious effect on plate performance.
[0016] It is yet another object of the present invention to achieve
plate improvements with only small amounts of a strong,
non-volatile acid.
[0017] These and other objectives are achieved by an imageable
composition according to the present invention, which uses only
small amounts of a strong, non-volatile acid and has an improved
cure rate, processing latitude, processing robustness, long shelf
life of the acid curable composition, improved formulating scope
and moderate energy requirement of the acid generation step.
SUMMARY OF THE INVENTION
[0018] The present invention provides an imageable composition,
which includes a bottom layer including a first strong,
non-volatile acid having a pKa of not more than about 8 and coated
thereon a top layer including an acid curable composition, an acid
generator, an infrared absorber and optionally a colorant.
[0019] The present invention further provides an imageable element,
which includes a substrate and an imageable composition coated on a
surface of the substrate, the imageable composition including: a
bottom layer including a first strong, non-volatile acid having a
pKa of not more than about 8; and coated thereon a top layer
including an acid curable composition, an acid generator, an
infrared absorber and optionally a colorant.
[0020] The present invention further provides a method of producing
an imaged element. The method includes the steps of:
[0021] providing an imageable element including a substrate and an
imageable composition coated on a surface of the substrate, the
imageable composition including: a bottom layer including a first
strong, non-volatile acid having a pKa of not more than about 8,
and coated thereon a top layer including an acid curable
composition, an acid generator, an infrared absorber and optionally
a colorant;
[0022] imagewise exposing the imageable element to radiation to
produce an imagewise exposed element having exposed and unexposed
regions;
[0023] baking the imagewise exposed element at a temperature and
period of time sufficient to produce a cured element; and
[0024] contacting the cured element and a developer to remove the
unexposed regions and thereby produce the imaged element.
[0025] It was unexpectedly discovered that inclusion in the
thermally imageable compositions of dyes, such as, D11 dye, which
have counter anions that combine with protons to produce
non-volatile acids, significantly improves cure rate and processing
latitude of the composition. It was also found that incorporating a
small amount of a sulfonic acid into pre-heat, thermal plate
increases the speed of the thermal plate and allows maximum image
density at wider pre-heat temperatures. It also provides
significantly improved processing latitude while maintaining an
adequate shelf life.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 depicts a plot of Solid Density (D.sub.max) of
thermally exposed, pre-heated and developed plates versus Exposure
Energy (mJ/cm.sup.-2).
DETAILED DESCRIPTION OF THE INVENTION
[0027] Lithographic printing plate precursors, i.e., imageable
elements, typically include a radiation imageable coating applied
over a support material, such as, an aluminum substrate. If after
exposure to radiation, the exposed regions of the coating become
soluble and are removed in the developing process, revealing the
underlying hydrophilic surface of the support, the plate is called
a positive-working printing plate. Conversely, if exposed regions
of the plate become insoluble in the developer and the unexposed
regions are removed by the developing process, the plate is called
a negative-working plate. In each instance, the regions of the
radiation-sensitive layer that remain (i.e., the image areas) are
ink-receptive and the regions of the hydrophilic surface revealed
by the developing process accept water and repel ink.
[0028] To improve cure rate and processing latitude of the
thermally imageable layer, the present invention provides an
imageable composition, which includes a bottom layer including a
first strong, non-volatile acid having a pKa of not more than about
8 and coated thereon a top layer including an acid curable
composition, an acid generator, an infrared absorber and optionally
a colorant. Preferably, at least one of the infrared absorber and
the colorant has a counter anion derived from a non-volatile
acid.
[0029] Incorporating a bottom layer, also referred to herein as a
"subbing" layer, of a strong, non-volatile acid, such as, a
sulfonic acid, onto the aluminum support before applying the heat
sensitive pre-heated, negative working, thermal composition,
increases the speed of the system and allows maximum image density
at wider pre-heat temperatures, resulting in an improved processing
latitude, while maintaining an adequate shelf-life. Surprisingly,
only very small amounts of a strong, non-volatile acid, such as, a
sulfonic acid material is required to achieve such plate
improvements. The term "pre-heated plate" in the context of the
present invention refers to a plate that is heated after an
imagewise exposure, but before development.
[0030] The "subbing" layer may be applied to the support using a
suitable method known in the art, such as, bar coating, whirl
coating, reverse roll coating, curtain coating, dip coating or slot
coating. The "subbing" layer and the top layer may be applied by
the same method, or each can be applied by a different method,
including any of the above application methods. The present
invention is useful in negative-working printing plates, such as,
Thermal Printing Plate/830, available from Kodak Polychrome
Graphics, Norwalk, Conn.
[0031] The term "hydrocarbyl" in the context of the present
invention refers to a linear, branched or cyclic alkyl, alkenyl,
aryl, aralkyl or alkaryl of 1 to 22 carbon atoms, substituted
derivatives thereof, wherein the substituent group is selected from
halogen, hydroxy, hydrocarbyloxy, carboxyl, ester, ketone, cyano,
amino, amido and nitro groups. Hydrocarbyl groups in which the
carbon chain is interrupted by oxygen, nitrogen or sulfur are also
included in the term "hydrocarbyl".
[0032] Preferably, the imageable composition of the present
invention is thermally imageable, so that the imageable element
according to the present invention is infrared radiation imageable.
Thus, in the method of the present invention, the step of imagewise
exposing the imageable element to radiation is preferably carried
out using an infrared radiation. Upon such imaging the developer
solubility of the imaged area is decreased to allow differentiation
between imaged and non-imaged areas upon development.
[0033] It has been found that replacing the current blue dye
(Victoria Blue FBO) with D11 blue dye into pre-heat, thermal plate
increases the speed of the thermal plate and allows maximum image
density at wider pre-heat temperatures (improved processing
latitude). It is believed that such improvements result from the
presence of one or more components in the composition which contain
anions derived from a non-volatile acid so that when such anions
are combined with a proton, they produce a non-volatile acid, which
cannot escape from the coating during processing.
[0034] The anions capable of producing a non-volatile acid might be
donated from an IR dye, such as the following: 1
[0035] Alternatively, the anions capable of producing non-volatile
acid might be provided from, for example, a blue colorant dye, such
as D11 dye having the structure A shown below: 2
[0036] In the context of the present invention, the term "colorant"
includes colorant dyes and colorant pigments.
[0037] The acid curable composition can include a binder and a
crosslinking agent for that binder. Suitable binders include
polymers that have at least two, preferably more than two reactive
groups, such as, hydroxy, carboxylic acid, amine, carbamate, amide,
sulfonamide or imide. Preferably, the reactive group is a hydroxy
group, such that, the polymer can be a polyol, a polyether polyol,
a novolak resin, a hydroxyfunctional acrylic resin, a
hydroxyfunctional polyester resin and combination thereof.
[0038] The crosslinking agent can be any suitable crosslinking
agent known in the art and includes crosslinking agents, such as, a
resole resin, an amino resin, an amido resin, an epoxy compound
having at least two epoxide groups and the like. A combination of
the aforementioned crosslinkers can also be used.
[0039] The crosslinking agent preferably is an amino resin that has
at least two alkoxymethyl groups, including amino resins, such as,
an alkoxymethylated melamine resin, an alkoxymethylated
benzoguanamine resin, an alkoxymethylated glycoluril, an
alkoxymethylated polyacrylamid, an alkoxymethylated
polymethacrylamid and a combination thereof. Preferably, the alkyl
group in the alkoxymethylated amino resins is derived from an
alcohol of 1 to 4 carbon atoms, such as methanol, ethanol,
propanol, butyl alcohol, isomers thereof and mixtures thereof.
Examples of such amino resins include alkoxymethylated melamine
resins having from about 2 to about 6 methoxymethyl groups.
[0040] The acid curable composition can include a self-crosslinking
material, such as, a resole resin. However, in addition to the
resole resin, the acid curable composition can further include a
polymer having at least two reactive groups, such as, hydroxy,
carboxylic acid, amine, carbamate, amide, sulfonamide or imide, to
form a crosslinked network with the resole resin. Preferably, the
acid curable composition includes a resole resin and a novolak
resin.
[0041] The acid curable composition can further contain an
isocyanate crosslinker that has at least two, preferably more than
two isocyanate groups. Such isocyanate crosslinkers include
diisocyanates, such as, isophorone diisocyanate,
methylene-bis-phenyl diisocyanate, toluene diisocyanate,
hexamethylene diisocyanate, tetramethylxylylene diisocyanate,
dimers thereof, adducts thereof with diols or triols, and mixtures
thereof.
[0042] The imageable composition of the present invention also
includes, in the top layer, an acid generator, which is an
ultraviolet, visible or infrared radiation or heat activated
compound. Upon exposure to ultraviolet, visible radiation, infrared
radiation or heat, either directly, or indirectly through heat
transfer from an infrared absorbing compound, the acid generator
produces a free acid, which acts as a cure catalyst for the curing
process.
[0043] Suitable acid generators include onium salts, covalently
bound sulfonate group containing compounds,
hydrocarbylsulfonamido-N-hydrocarby- l sulfonate and a combination
thereof. Examples of the covalently bound sulfonate group
containing compounds include hydrocarbyl sulfonates, such as,
methyl tosylate, ethyl tosylate, benzoin tosylate, and the
like.
[0044] When an ultraviolet radiation is used with a thermally
activated acid generator, the composition can further include a
photothermal converter material for converting ultraviolet energy
to thermal energy. In addition, a UV/visible sensitizer selected
from monomolecular or polymeric compounds containing an anthracene
moiety, thioxanthone moiety or alkylaminobenzophenone moiety can
also be used. However, in the case of UV-activated acid generators,
the use of a photothermal converter material is not necessary.
[0045] The term "volatile acid" in the context of the present
invention refers to hydrogen halides such as HF, HCl, HBr and Hl,
which can escape from the imageable composition during imaging
and/or baking steps. The term "non-volatile acid" in the context of
the present invention refers to any non-halogen acid.
[0046] The use of counter anions derived from a non-volatile acid,
which can combine with protons to produce non volatile acids
increases the speed of thermally imageable, pre-heated, negatively
working patterning compositions, especially printing plates.
[0047] Preferably, the acid generator is an onium salt that has a
non-nucleophilic counter anion derived from a non-volatile acid,
such as, sulfate, bisulfate, tetrafluoroborate,
hexafluorophosphate, hexafluoroarsenate, hexafluoroantimonate,
tetrakis(pentafluorophenyl)-bor- ate, triflate,
pentafluoropropionate, pentafluoroethanesulfonate,
benzenesulfonate, p-methylbenzenesulfonate and
pentafluorobenzenesulfonat- e.
[0048] Examples of such onium salts include iodonium salts,
sulfonium salts, hydrocarbyloxysulfonium salts,
hydrocarbyloxyammonium salts, aryl diazonium salts and combinations
thereof. Examples of the hydrocarbyloxy ammonium salts include the
salts of N-hydrocarbyloxy substituted nitrogen containing
heterocyclic compounds, such as, N-ethoxyisoquinolinium
hexafluorophosphate. Examples of the iodonium salts include
4-octyloxyphenyl phenyliodonium hexafluoroantimonate.
[0049] Preferably, the acid generator is a monomeric or oligomeric
aromatic diazonium salt. The monomeric and oligomeric diazonium
salts can be any diazonium salt known in the art that is suitable
for use in thermal imaging, provided that the diazonium salt has a
counter anion that is other than halide.
[0050] Examples of such counter anions include sulfate, bisulfate,
tetrafluoroborate, hexafluorophosphate, hexafluoroarsenate,
hexafluoroantimonate, tetrakis(pentafluorophenyl)borate, triflate,
pentafluoropropionate, pentafluoroethanesulfonate,
benzenesulfonate, p-methylbenzenesulfonate and
pentafluorobenzenesulfonate. Preferably, such diazonium salts are
aromatic and more preferably, are derivatives of
diphenylamine-4-diazonium salts, including, for example, for
example, 4-diazodiphenylamine sulfate. Examples of such aromatic
diazonium salts include: diphenyl-4-diazonium sulfate;
2-4-(N-(naphthyl-2-methyl)-N-propy- lamino)-benzenediazonium
sulfate; chloro-diphenyl-4-diazonium sulfate;
4-(3-phenylpropylamino)-benzenediazonium sulfate;
4-(N-ethyl-N-(benzyl)-a- mino)-benzenediazonium sulfate;
4-(N,N-dmethyl-amino)-benzenediazonium tetrafluoroborate;
4-(N-(3-phenyl-mercapto-propyl)-N-ethyl-amino)-2-chlor-
obenzenediazonium sulfate; 4-(4-methylphenoxy)-benzenediazonium
sulfate; 4-(phenylmercapto)-benzenediazonium sulfate;
4-phenoxybenzenediazonium sulfate;
4-(benzoylamino)-benzenediazonium hexafluorophosphate;
methylcarbazole-3-diazonium sulfate;
3-methyl-diphenyleneoxide-2-diazoniu- m sulfate,
3-methyldiphenylamine-4-diazonium sulfate,
2,3',5-trimethoxydiphenyl-4-diazonium sulfate;
2,4',5-triethoxydiphenyl-4- -diazonium sulfate;
4-(3-(3-methoxyphenyl)-propylamino)-benzenediazonium sulfate;
4-(N-ethyl-N-(4-methoxybenzyl)-amino)-benzenediazonium sulfate;
4-(N-(naphthyl-(2)-methyl)-N-n-propylamino)methoxybenzenediazonium
sulfate;
4-(N-(3-phenoxypropyl)-N-methylamino)-2,5-dimethoxybenzenediazon-
ium tetrafluoroborate;
4-(N-(3-phenylmercaptopropyl)-N-ethylamino)-2-chlor-
o-5-methoxybenzenediazonium sulfate;
4-(4-(3-methylphenoxy)-phenoxy)-2,5-d- imethoxybenzenediazonium
sulfate; 4-(4-methoxy-phenylmercapto)-2,5-diethox-
ybenzenediazonium sulfate; 2,5-diethoxy-4-phenoxybenzenediazonium
sulfate; 4-(3,5-dimethoxybenzoylamino)-2,5-diethoxybenzenediazonium
hexafluorophosphate; methoxycarbazole-3-diazonium sulfate;
3-methoxy-diphenyleneoxide-2-diazonium sulfate and
methoxydiphenylamine-4-diazonium sulfate.
[0051] Diazonium salts derived from the following amines are also
suitable for use in the present invention:
4-amino-3-methoxydiphenylamine, 4-amino-2-methoxydiphenylamine,
4'-amino-2-methoxydiphenylamine, 4'-amino-4-methoxydiphenylamine,
4-amino-3-ethoxydiphenylamine, 4-amino-3-hexyloxydiphenylamine,
4-amino-3-beta-hydroxyethoxy-diphenylami- ne,
4'-amino-2-methoxy-5-methyldiphenylamine,
4-amino-3-methoxy-6-methyldi- phenylamine,
4'-amino-4-n-butoxydiphenylamine, 4'-amino-3',4-dimethoxydiph-
enylamine, 4-amino-diphenylamine, 4-amino-3-methyl-diphenylamine,
4-amino-3-ethyldiphenylamine, 4'-amino-3-methyl-diphenylamine,
4'-amino-4-methyl-diphenylamine,
4'-amino-3,3'-dimethyldiphenylamine,
3'-chloro-4-amino-diphenylamine, 4-aminodiphenylamine-2-sulfonic
acid, 4-aminodiphenylamine-2-carboxylic acid,
4-aminodiphenylamine-2'-carboxyli- c acid and
4'-bromo-4-aminodiphenylamine. Preferred are 4-amino-diphenylamine,
3-methyl-4-aminodiphenylamine, 3-alkoxy-4-aminodiphenylamines
having 1 to 3 carbon atoms in the alkoxy group and
3-methoxy-4-aminodiphenylamine.
[0052] Preferably, the counter anion of the aromatic diazonium salt
can be mesitylene sulfonate, toluene sulfonate, methane sulfonate,
naphthalene sulfonate, trifluoromethane sulfonate,
hexafluorophosphate and tetrafluoroborate.
[0053] Examples of the particularly preferred monomeric aromatic
diazonium salts include 2-methoxy-4-phenylaminobenzenediazonium
hexafluorophosphate (diazo MSPF6) represented by the formula: 3
[0054] 2-methoxy-4-phenylaminobenzenediazonium p-toluenesulfonate
represented by the formula: 4
[0055] and a combination thereof.
[0056] Examples of the particularly preferred oligomeric aromatic
diazonium salts include compounds represented by the formula: 5
[0057] which is manufactured by St. Jean Photochemicals, Quebec,
Canada, under the trade name DTS-18; 6
[0058] wherein n is from 1 to I 11; and a combination thereof.
Mixtures of any of the aforementioned diazonium salts are also
suitable.
[0059] In addition to the acid generator, the imageable composition
of the present invention can optionally include a strong acid in
the acid curable composition, which is in the top layer.
[0060] The imageable composition of the present invention includes
a strong acid in the bottom layer. In addition to the strong,
non-volatile acid, the bottom layer can optionally include a
binder, such as, a novolak resin, a resole resin, an amino resin,
an epoxy resin, a polyurethane resin, a polyacetal resin or a
combination thereof.
[0061] The term "strong acid" is defined herein as an acid that has
a pKa of not more than about 8. Preferably, the strong acid of the
present invention has a pKa of not more than about 5. More
preferably, the strong acid of the present invention has a pKa of
not more than about 4. Examples of such strong acids include
sulfonic acids represented by the formula:
R--SO.sub.3H
[0062] wherein R is a substituted or unsubstituted hydrocarbyl of 1
to 22 carbon atoms, a substituted or unsubstituted aryl of 6 to 22
carbon atoms. Mixtures of these acids can also be used to obtain
desired cure rates and properties.
[0063] The alkyl sulfonic acids can be represented by the above
formula, wherein the R group is preferably a linear, branched or
cyclic alkyl of 1 to 22 carbon atom or a linear, branched or cyclic
haloalkyl of 1 to 22 carbon atom having at least one halogen.
Mixtures of these acids can also be used. Preferably, the haloalkyl
group has two or more halogen atoms. Preferred halogens include
chlorine and fluorine.
[0064] The aryl sulfonic acids can be represented by the formula:
7
[0065] wherein each of R.sup.1, R.sup.2, R.sup.3, R.sup.4 and
R.sup.5 can independently be hydrogen, an alkyl of 1 to 12 carbon
atoms, a haloalkyl of 1 to 22 carbon atoms having at least one
halogen, an aryl of 6 to 12 carbon atoms, a halogen, a hydroxy, an
alkoxy, a cyano, a nitro, an alkoxycarbonyl or an acyl group
represented by the formula: 8
[0066] wherein R.sup.6 can be hydrogen, alkyl of 1 to 12 carbon
atoms, haloalkyl of 1 to 12 carbon atoms having at least one
halogen atom, alkoxy, cyano, nitro, alkoxycarbonyl and acetyl.
[0067] A preferred class of aryl sulfonic acids can be represented
by the formula: 9
[0068] wherein each of R.sup.1, R.sup.4 and R.sup.6 can be
hydrogen, alkyl of 1 to 12 carbon atoms, haloalkyl of 1 to 12
carbon atoms having at least one halogen, aryl of 6 to 12 carbon
atoms, halogen, hydroxy, alkoxy, cyano, nitro, alkoxycarbonyl or
acyl and wherein R.sup.7 can be hydrogen, alkyl of 1 to 12 carbon
atoms, haloalkyl of 1 to 12 carbon atoms having at least one
halogen, aryl of 6 to 12 carbon atoms, alkoxycarbonyl and acyl. An
example of such an aryl sulfonic acid is
3-benzoyl-4-hydroxy-6-methoxybenzenesulfonic acid.
[0069] The imageable composition of the present invention includes
an infrared absorber. Preferably, the infrared absorber has a
counter anion derived from a non-volatile acid. Suitable infrared
absorbers include pigments and dyes, or a combination thereof.
[0070] Examples of the preferred pigments include black pigments,
yellow pigments, orange pigments, brown pigments, red pigments,
purple pigments, blue pigments, green pigments, fluorescent
pigments, metal powder pigments, polymer bond pigments, insoluble
azo pigments, azo lake pigments, condensation azo pigments, chelate
azo pigment, phthalocyanine pigments, anthraquinone pigments,
perylene pigments, perynone pigments, thioindigo pigments,
quinacridone pigments, dioxazine pigments, isoindolinone pigments,
quinophthalone pigments, colored lake pigments, azine pigments,
nitroso pigments, nitro pigments, natural pigments, fluorescent
pigments, inorganic pigments, carbon black, Paris Blue, Prussian
Blue or any combination thereof.
[0071] Examples of the preferred dyes include cyanine dyes,
squarylium dyes, pyrylium salts and nickel thiolate complexes.
[0072] A particularly useful class of infrared absorbing dyes
includes compounds represented by the formula: 10
[0073] wherein each R.sup.1, R.sup.2, R.sup.3 and R.sup.4 is
independently selected from the group consisting of: a linear,
branched or cyclic alkyl of 1 to 12 carbon atoms, alkenyl of 1 to
12 carbon atoms, alkoxy of 1 to 12 carbon atoms in the alkyl and
aryl of 1 to 12 carbon atoms,
[0074] wherein each pair selected from the group consisting of:
R.sup.1 and R.sup.1 and R.sup.3 and R.sup.4 may be bonded together
to form a fused aromatic ring;
[0075] wherein each R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9 and
R.sup.10 is independently selected from the group consisting of: a
linear, branched or cyclic alkyl of 1 to 12 carbon atoms, wherein
each of the alkyls can independently have a substituent;
[0076] wherein each R.sup.11, R.sup.12 and R.sup.13 is
independently selected from the group consisting of: hydrogen
halogen, a linear, branched or cyclic alkyl of 1 to 8 carbon atoms,
wherein each of the alkyls can independently have a substituent;
wherein R.sup.12 may be bonded to R.sup.11 0r R.sup.13 to from a
ring structure; and when m is greater than 2, a plurality of
R.sup.12 may bonded to each other to form a ring structure;
[0077] wherein each R.sup.14 and R.sup.15 is independently selected
from the group consisting of: hydrogen halogen, a linear, branched
or cyclic alkyl of 1 to 8 carbon atoms, wherein each of the alkyls
can independently have a substituent; wherein R.sup.14 may be
bonded to R.sup.15 to form a ring structure; and when m is greater
than 2, a plurality of R.sup.14 may bonded to each other to form a
ring structure; and
[0078] wherein m is an integer from 1 to 8; and X.sup.31 is a
counter anion derived from either a volatile or a non-volatile
acid.
[0079] Preferably, the counter anion in the above infrared
absorbing dyes is derived from a non-volatile acid. Alternatively,
the colorant, such as, the colorant dye or the colorant pigment,
which may also be present in the composition, can have a
non-volatile counter anion. If both an infrared absorbing dye and a
colorant are present, preferably at least one of the two, i.e.,
either the infrared absorber or the colorant, and more preferably
both, have a counter anion derived from a non-volatile acid.
However, if only an infrared absorbing dye is present in the
composition, then the infrared absorbing dye preferably has a
counter anion derived from a non-volatile acid. However, either the
colorant or the infrared absorbing dye, or both, can have counter
anions derived from a volatile acid.
[0080] Specific examples of dyes having a counter anion derived
from a non-volatile acid include the following compounds: 11
[0081] These dyes have the property of generating heat upon
absorbing light. Furthermore, they have an infrared absorb band in
the range from 700 to 1200 nm and thus, are suitable for use in the
imageable compositions of the present invention.
[0082] Further examples of dyes and pigments include triarylamine
dyes, thiazolium dyes, indolium dyes, oxazolium dyes, cyanine dyes,
polyaniline dyes, polypyrrole dyes, polythiophene dyes, thiolene
metal complex dyes, carbon black and polymeric phthalocyanine blue
pigments and those that are mentioned in U.S. Pat. Nos. 5,919,601;
3,218,167; and 3,884,693, the contents of which are incorporated
herein by reference in their entirety as fully set forth.
[0083] The present invention also provides an imageable element,
which employs the imageable composition of the present invention.
The imageable element includes a substrate and an imageable
composition according to the present invention coated on a surface
of the substrate.
[0084] The substrate of the imageable element is typically an
aluminum sheet. However, other materials that are commonly known to
those skilled in the art can also be used.
[0085] Suitable substrates include any sheet material
conventionally used to prepare lithographic printing plates,
including metals such as aluminum sheets; paper; paper coated on
one or both sides with an alpha-olefin polymer such as
polyethylene; acetate films such as polyvinyl acetate and cellulose
acetate film; polyvinyl acetal film; polystyrene film;
polypropylene film; polyester film such as polyethylene
terephthalate film; polyamide film; polyimide film; nitrocellulose
film; polycarbonate film; polyvinylchloride film; composite films
such as polyester, polypropylene or polystyrene film coated with
polyethylene film; metalized paper or films; metal/paper laminates;
Perlon gauze; plates of magnesium, zinc, copper, anodized aluminum,
electrochemically roughened aluminum, steel, and the like.
[0086] A preferred substrate for the imageable element of present
invention is an aluminum sheet. The surface of the aluminum sheet
may be treated with metal finishing techniques known in the art
including physical roughening, electrochemical roughening, chemical
roughening, anodizing, and silicate sealing and the like.
[0087] The preferred aluminum substrate is
electrochemically-grained and anodized aluminum, such as commonly
used for lithographic printing plates. Anodized substrates can be
prepared using sulfuric acid anodization, phosphoric acid
anodization or a combination thereof. Other conventional
anodization methods can also be used in the preparation of the
anodized substrate of the present invention.
[0088] Prior to the application of the subbing layer, the aluminum
substrate is preferably grained, anodized and post-treated.
Graining (or roughening) can be accomplished by mechanical or
electrochemical processes or by a combination of both processes.
Preferred post-treatments include silication and polyvinyl
phosphonic acid. Post-treatment with phosphate or
phosphate/fluoride, followed by silication, can also be used.
[0089] The imageable layer can then be applied using the
application methods known in the art.
[0090] Preferably, the strong, non-volatile acid, such as, a
sulfonic acid, is applied onto the aluminum support before applying
the heat sensitive preheated, negative working, thermal
composition.
[0091] Typically, the strong, non-volatile acid is dissolved in
water and the aqueous solution is coated onto the aluminum
substrate. In a laboratory environment, the subbing layer can be
applied by means of a wire wound bar, such that the dry film
coverage is, for example, about 0.04 gm.sup.-2. In a manufacturing
environment, the subbing layer is typically applied by slot coating
or reverse roll coating. The bottom layer (sub layer) is then
dried, for example, at about 90.degree. C. for about 90
seconds.
[0092] The acid curable composition in the top layer on the other
hand is typically dissolved in a solvent, preferably an organic
solvent or solvents and, thereafter, applied onto the bottom layer
(sub layer).
[0093] After proper drying, the coating weight of the imaging layer
preferably is in the range of about 0.2 to about 5.0 g/m.sup.2, and
more preferably in the range from about 0.7 to about 2.5
g/m.sup.2.
[0094] The imageable element of the present invention is suitable
for use in single as well as multilayer imageable elements that are
useful in lithographic printing, including lithographic printing
plates that can be thermally imaged by imagewise exposure with a
laser or a thermal printing head. The multilayer imageable element
is useful as a precursor for a lithographic printing member.
[0095] In addition to the imageable layer, the imageable element
can have additional layers, such as, an underlying layer.
[0096] Possible functions of an underlying layer include:
[0097] (1) to enhance developability of the imagewise unexposed
areas; and
[0098] (2) to act as a thermal insulating layer for the imagewise
exposed areas.
[0099] Such thermal insulating polymeric layer prevents otherwise
rapid heat dissipation, for example, through the heat conducting
aluminum substrate. This allows more efficient thermal imaging
throughout of the imageable layer, particularly in the lower
sections. In accordance with these functions, the underlying layer
should be soluble or at least dispersible in the developer and,
preferably, have a relatively low thermal conductivity
coefficient.
[0100] The imageable element can further have an overlying layer.
Possible functions of an overlying layer include:
[0101] (1) to prevent damage, such as scratching, of the surface
layer during handling prior to imagewise exposure; and
[0102] (2) to prevent damage to the surface of the imagewise
exposed areas, for example, by over-exposure, which could result in
partial ablation.
[0103] The overlying layer should be soluble, dispersible or at
least permeable to the developer.
[0104] Further, known plasticizers, adhesion promoters, flow
control agents and/or UV absorbers can be added to the copying
compositions of the invention. The type and quantity of such
additives depend on the purpose for which the imageable element
according to the present invention is intended for use. In any
case, however, care must be taken that the substances added do not
absorb an excessive proportion of the radiation required for acid
generation and thus reduce the crosslinking sensitivity of the
composition.
[0105] Suitable plasticizers include dioctyl phthalate, dibutyl
phthalate, diisooctyladipate, nitro esters, alkyl and aryl
phosphate esters, chlorinated paraffins. Glycols or aliphatic
polyols can also be added. If it is desired to ensure good
storability under relative high atmospheric moisture conditions,
the use of water-insoluble plasticizers is preferred.
[0106] Adhesion promoters can also be added. Suitable adhesion
promoters include monomeric or polymeric organic silanes,
nitrogen-containing heterocyclic compounds, such as those disclosed
in U.S. Pat. Nos. 3,645,722, 3,622,234, and 3,827,908, heterocyclic
mercaptan compounds, mercapto alkanoic acid anilides and mercapto
alkanoic acid esters.
[0107] The present invention also provides a method of producing an
imaged element, which includes the steps of:
[0108] providing an imageable element including a substrate and an
imageable composition coated on a surface of the substrate, the
imageable composition including: a bottom layer including a first
strong, non-volatile acid having a pKa of not more than about 8,
and coated thereon a top layer including an acid curable
composition, an acid generator, an infrared absorber and optionally
a colorant;
[0109] imagewise exposing the imageable element to radiation to
produce an imagewise exposed element having exposed and unexposed
regions;
[0110] baking the imagewise exposed element at a temperature and
period of time sufficient to produce a cured element; and
[0111] contacting the cured element and a developer to remove the
unexposed regions and thereby produce the imaged element.
[0112] The method can be practiced by imagewise exposing the
imageable element to ultraviolet radiation provided that the
thermally imageable composition includes a photothermal converting
material. The exposing step of this method is preferably carried
out using an infrared laser. However, other methods such as visible
or UV laser imaging may also be used, provided that a
photoconverter, i.e., a photothermal converter, is present. Thus,
for exposure with such visible or UV radiation sources, the
imageable composition generally includes a photothermal converting
material.
[0113] The printing plates, forms, screens, resists and the like,
are prepared in the customary manner from the appropriate
materials. After exposure, the non-image areas of the layer, which
have retained their solubility, are removed by treatment with a
suitable developer, such as, an aqueous acid or base solution.
[0114] The imaging layer of the imageable element is negative
working.
[0115] Preferably, the imaging layer is thermally imageable, so
that the imageable element according to the present invention is
infrared radiation imageable. Thus, in the method of the present
invention, the step of imagewise exposing the imageable element to
radiation is carried out using an infrared radiation. Upon such
imaging the developer solubility of the imaged area is decreased to
allow differentiation between imaged and non-imaged areas upon
development.
[0116] Following imagewise exposure by analog or digital means, an
imaged element having exposed areas and complimentary unexposed
areas is obtained. Thereafter, the exposed plate precursor is baked
at a temperature from about 220.degree. F. to about 280.degree. F.,
preferably from about 240.degree. F. to about 260.degree. F. for a
period of time from about 45 seconds to about 75 seconds,
preferably from about 55 seconds to about 65 seconds. The exposed
plate precursor is then developed with a developer capable of
selectively removing the uncrosslinked materials in the unexposed
regions.
[0117] The developer composition is dependent on the nature of the
polymeric substance, but is preferably an aqueous composition.
Common components of aqueous developers include surfactants,
chelating agents, such as, salts of ethylenediamine tetraacetic
acid, organic solvents, such as, benzyl alcohol, ethylene glycol
monomethyl ether, ethylene glycol monoethyl ether, diacetone
alcohol, butyl acetate, ethylene glycol methyl ether acetate,
methyl isobutyl ketone and a mixture thereof, and alkaline
components, such as organic amines, including alkanol amines, such
as triethanol amine and methyl diethanol amine, inorganic
metasilicates, organic metasilicates, hydroxides and
bicarbonates.
[0118] The pH of the aqueous developer is preferably within about 5
to about 14, depending on the nature of the composition of the
imaging layer. The development can be performed by any known
manner, for instance, by rubbing the plate surface with a
developing pad containing the foregoing developer or by pouring the
developer on the plate surface and then rubbing the surface with a
developing brush in water.
[0119] The inventors have surprisingly discovered that
incorporating a small amount of a sulfonic acid into pre-heat,
thermal plate increases the speed of the thermal plate and allows
maximum image density at wider pre-heat temperatures. In addition,
it provides significantly improved processing latitude while
maintaining an adequate shelf life.
[0120] For example, when an experiment was completed adding 0 to 1
% 3-benzoyl-4-hydroxy-6-methoxybenzenesulfonic acid (HMBS) into a
series of coatings for thermal pre heat plates, dramatic increases
in speed were found at 0.04% level. In addition the formulation had
a 30 to 40.degree. F. pre heat window. With pre heat plates
including the 3-benzoyl-4-hydroxy-6-methoxybenzene sulfonic acid
(HMBS), plate speed was around 80 MJ/cm.sup.-2 with a 250.degree.
F. pre-heat temperature, when the plate system was developed in
MX1710.
[0121] The present invention further provides an improved
formulating scope. Previous attempts to improve speed and fog
control have had deleterious effects on plate performance. Thus, if
one is able to prepare a fast plate, a plate having a poor shelf
life is obtained. Conversely, if a plate having a good shelf life
is prepared, a slow plate is obtained. In contrast, the present
invention provides a substantial improvement in the speed and
processing robustness of thermal, pre-heated, negatively working
patterning compositions, such as, printing plates, forms, screens,
resists, and the like, while maintaining adequate shelf life,
improvements in plate speed and increased processing latitude of
thermal, pre-heat negative plates.
[0122] The invention is further described in the following
examples, which are intended to be illustrative and not
limiting.
EXAMPLES
[0123] The following are referred to hereinafter:
[0124] (1) Resin A--a resole resin, UCAR phenolic resin BKS-5928 as
supplied by Union Carbide Corporation.
[0125] (2-a) Resin B--a novolak resin solution, N13 as supplied by
Eastman Kodak Company.
[0126] (2-b) Resin BB--a solid novolak resin, N-9P as supplied by
Eastman Kodak Company.
[0127] (3) Acid generator A--Diazo MSPF6 as supplied by Diversitec
Corporation, Fort Collins, Colorado having the following structure:
12
[0128] (4) IR dye A--having the following structure: 13
[0129] (5) Terephthaldehyde as supplied by Aldrich Chemical
Company, Milwaukee, Wis.
[0130] (6) Blue dye A--Simbase Victoria Blue FBO 23363, as supplied
by Charkit Chemical Corporation, Darien, Conn.
[0131] (7) Blue Dye B--D11 dye having the structure: 14
[0132] (8) Substrate--0.3 mm thick sheets of aluminum that had been
electrograined, anodised and post-anodically treated with an
aqueous solution of an inorganic phosphate.
[0133] (9-a) Developer A--9005+ as supplied by Kodak Polychrome
Graphics.
[0134] (9-b) Developer AA--MX1710 as supplied by Kodak Polychrome
Graphics.
[0135] (10) Creo trendsetter 3244: a commercially available
platesetter, operating at a wavelength of 830 nm, as supplied by
Creo products of Canada.
[0136] (11) Gretag Macbeth D19C densitometer: a commercially
available densitometer as supplied by Color data systems Limited of
the Wirral, UK.
[0137] (12) HMBS--3-benzoyl-4-hydroxy-6-methoxybenzenesulfonic acid
as supplied by Aldrich
[0138] (13) Development aid XDSA, having the structure: 15
Examples C1, 1 and 2
[0139] Coating formulations included solutions of the components
described in table 1 in 1-methoxypropan-2-ol/acetone 92:8 (w:w).
Plates were prepared by coating the formulations onto the aluminum
substrate by means of a whirl coater. The formulation
concentrations were selected to provide dry films having a coating
weight of 120 mg/ft. The coated plates were dried at 100.degree. C.
for 90 seconds. The film weights were measured after thorough air
drying over several days.
1 TABLE 1 Example C1 1 2 Component Parts by Weight Resin A 28.2
28.2 28.0 Resin B 48.3 48.3 47.9 Acid Generator A 7.5 7.5 7.4 IR
Dye A 8.6 8.6 8.5 Terephthaldehyde 6.5 6.5 6.4 Blue Dye A 0.9 0.9
Blue Dye B 0.9 0.9
Ascertaining Fog Point
[0140] Unimaged plate samples were placed in a heavy duty Wisconsin
oven (conveyor speed=2.5 feet/min) starting at a temperature of
275.degree. F. and decreasing by 5.degree. F. intervals. After
processing in a Mercury Mark V processor (containing 9005+developer
at 25.degree. C., processing speed 740 mm/min) the plates were
visually appraised for any remaining green coating. The point at
which the plates became completely free of coating was noted. In
this case, this was 268.degree. F. for all examples.
Thermal Exposure
[0141] Additional plate samples were then imaged on the Creo
Trendsetter at 54, 63, 76, 95, 127 and 190 mJ/cm.sup.-2, using an
internal solid image pattern (100% exposure). They were then
pre-heated in the Wisconsin oven as above, at 258.degree. F.
(10.degree. F. below fog point), and processed in the Mercury
processor as above.
[0142] The completed plates were assessed in 2 ways;
[0143] (a) The solid density (D.sub.max) of the thermally exposed,
pre-heated and developed coating was measured using an X-rite 408
densitometer
[0144] (b) The plates were visually appraised for banding
(variations in the solid coating from dark to light green caused by
incomplete cross-linking of the coating during pre-heating).
Results
[0145] Table 2 shows the presence of D11 dye reduces the amount of
imaging energy required to produce an exposed negative working
coating.
[0146] The results are expressed graphically in FIG. 1.
[0147] Table 3 shows the presence of D11 dye, increases the
resistance to banding.
2 TABLE 2 D.sub.max at stated imaging energy density (mJ/cm.sup.-2)
Example 54 63 76 95 127 190 C1 0.38 0.44 0.70 0.91 0.90 0.86 1 0.51
0.79 0.90 0.90 0.85 0.83 2 0.40 0.55 0.84 0.90 0.89 0.85
[0148]
3 TABLE 3 Presence of banding Example 54 63 76 95 127 190 C1 yes
yes Yes yes no no 1 yes yes No no no no 2 yes yes Yes no no no
Examples C2 and 3
[0149] Coating formulations included solutions of the components
described in Table 4 in 1-methoxypropan-2-ol/acetone 92:8
(w:w).
4 TABLE 4 Example C2 3 Component Parts by Weight Resin A 28.6 28.6
Resin B 48.4 48.4 Acid Generator A 7.5 7.5 IR Dye A 7.8 7.8
Terephthaldehyde 6.5 6.5 Blue Dye A 1.2 Blue Dye B 1.2
[0150] Plates were prepared by coating the formulations onto the
aluminum substrate by means of a whirl coater. The formulation
concentrations were selected to provide dry films having a coating
weight of 120 mg/ft. The coated plates were dried at 100.degree. C.
for 90 seconds. The film weights were measured after thorough air
drying over several days.
Ascertaining Fog Point
[0151] Unimaged plate samples were placed in a heavy duty Wisconsin
oven (conveyor speed=2.5 feet/min) starting at a temperature of
275.degree. F. and decreasing by 5.degree. F. intervals.
[0152] After processing in a Mercury Mark V processor (containing
9005+ developer at 25.degree. C., processing speed 740 mm/min) the
plates were visually appraised for any remaining green coating. The
point at which the plates became completely free of coating was
noted. In this case, this was 279.degree. F. for example C2 and
271.degree. F. for Example 3.
Thermal Exposure
[0153] Additional plate samples were then imaged on the Creo
Trendsetter at 74, 79, 84, 90, 95, 100, 105, 111, 116, 121, 126,
132, 137, 142, 148, 153,158 and 163 mJ/cm.sup.-2, using an internal
solid image pattern (100% exposure). They were then pre-heated in
the Wisconsin oven as above, at 2, 7, 12,17 and 22.degree. F. below
the relevant fog point, and were processed in the Mercury processor
as above.
[0154] The completed plates were assessed for banding (Table 5). It
can be seen that the presence of D11 dye increases the resistance
to banding.
5 TABLE 5 Presence of banding Imaging Energy 2.degree. F. below fog
7.degree. F. below fog 12.degree. F. below fog 17.degree. F. below
fog 22.degree. F. below fog Density mJcm.sup.-2 C2 3 C2 3 C2 3 C2 3
C2 3 74 Yes Slight Yes Yes Yes Yes Yes Yes Yes Yes 79 Yes No Yes
Slight Yes Yes Yes Yes Yes Yes 84 Yes No Yes No Yes Slight Yes Yes
Yes s 90 Yes No Yes No Yes No Yes Yes Yes Yes 95 Yes No Yes No Yes
No Yes No Yes Slight 100 Slight No Yes No Yes No Yes No Yes Slight
105 No No Slight No Yes No Yes No Yes Slight 111 No No No No Yes No
Yes No Yes No 116 No No No No Slight No Slight No Yes No 121 No No
No No No No Slight No Yes No 126 No No No No No No Slight No Yes No
132 No No No No No No Slight No Yes No 137 No No No No No No Slight
No Yes No 142 No No No No No No Slight No Yes No 148 No No No No No
No Slight No Yes No 153 No No No No No No Slight No Yes No 158 No
No No No No No No No Yes No 163 No No No No No No No No Slight
No
Examples 4 to 8
[0155] Coating formulations included solutions of the components
described in table 6 in 1-methoxypropan-2-ol/acetone 92:8 (w:w).
Plates were prepared by coating the formulations onto the aluminum
substrate by means of a whirl coater. The formulation
concentrations were selected to provide dry films having a coating
weight of 120 mg/ft. The coated plates were dried at 100.degree. C.
for 90 seconds. The film weights were measured after thorough air
drying over several days.
6 TABLE 6 Example 4 5 6 7 8 Component Parts by Weight Resin A 28.48
28.47 28.44 28.42 28.41 Resin B 48.60 48.55 48.51 48.49 48.46 Acid
Generator A 7.54 7.53 7.53 7.52 7.52 IR Dye A 7.88 7.87 7.86 7.86
7.85 Terephthaldehyde 6.54 6.53 6.52 6.52 6.52 Blue Dye B 0.96 1.05
1.14 1.19 1.24
Thermal Exposure
[0156] Plate samples were then imaged on the Creo Trendsetter at
55,64, 77,96,129 and 194 mJ/cm.sup.-2, using an internal solid
image pattern (100% exposure). They were then pre-heated in the
heavy duty Wisconsin oven (conveyor speed=2.5 feet/min), at a
temperature of 260.degree. F. After processing in a Mercury Mark V
processor (containing 9005+ developer at 25.degree. C., processing
speed 740 mm/min), the solid density (D.sub.max) of the thermally
exposed, pre-heated and developed plates was measured using an
X-rite 408 densitometer. MJ/cm.sup.-2
[0157] Table 7 shows increasing amounts of D11 dye, increase the
D.sub.max of the coating (i.e., the plate has a faster imaging
speed).
7 TABLE 7 D.sub.max at stated imaging energy density (mJ/cm.sup.-2)
Example 55 64 77 96 129 194 4 0.39 0.72 0.87 0.87 0.85 0.82 5 0.39
0.72 0.87 0.88 0.87 0.84 6 0.42 0.75 0.96 0.94 0.92 0.89 7 0.48
0.72 0.92 0.91 0.89 0.89 8 0.48 0.75 0.92 0.95 0.95 0.89
Examples C9, 9 and 10
[0158] For example 9, HMBS (0.4 g) was dissolved in water (200 g).
This was coated onto the aluminum substrate by means of a wire
wound bar, such that the dry film coverage was 0.04 gm.sup.-2. The
bottom layer (sub layer) was dried at 90.degree. C. for 90
seconds.
[0159] For example 10, HMBS (0.5 g) was dissolved in water (200 g).
This was coated onto the aluminum substrate as described above,
such that the dry film coverage was 0.05 gm.sup.-2.
[0160] For example C9, aluminum substrate was left unchanged.
[0161] Next, a coating formulation including the components
described in Table 8, in 1-methoxypropan-2-ol/acetone 97:3 (w:w)
was prepared. This was coated over the supports above, by means of
a wire wound bar and was dried at 90.degree. C. for 90 seconds. The
formulation concentrations were selected to provide dry films
having a coating weight of 120 mg/ft.
8 TABLE 8 Component Parts by Weight Resin A 39.99 Resin BB 51.23
Acid Generator A 2.57 IR Dye A 2.77 Terephthaldehyde 2.28 Blue Dye
A 0.30 XDSA 0.86
[0162] The plates were then imaged on the Creo Trendsetter at 84,
89, 95, 102, 110, 119, 130, 144, 160, 181, 209, 245, 298 and 379
mJcm.sup.-2, using an internal solid image pattern (100% exposure).
After imaging the plates were heated in a forced air oven at 230,
240, 250, 260 or 270.degree. F. for 1 minute, cooled and processed
in a mechanical processor using developer AA. The solid density
(D.sub.max) of the remaining coating was then measured using the
Gretag densitometer. The results can be seen in tables 9 to 13
below.
9TABLE 9 230 F. Heating Step D.sub.max at stated imaging energy
density/mJcm.sup.-2 Example 84 89 95 102 110 119 130 144 160 181
209 245 298 379 C9 0.61 0.61 0.61 0.61 0.61 0.61 0.60 0.61 0.60
0.62 0.66 0.73 0.76 0.79 9 0.61 0.61 0.60 0.60 0.68 0.74 0.76 0.80
0.84 0.85 0.86 0.88 0.92 0.95 10 1.06 1.09 1.1 1.11 1.09 1.10 1.12
1.13 1.12 1.09 1.09 1.14 1.14 1.13
[0163]
10TABLE 10 240 F. Heating Step D.sub.max at stated imaging energy
density/mJcm.sup.-2 Example 84 89 95 102 110 119 130 144 160 181
209 245 298 379 C9 0.60 0.59 0.60 0.60 0.60 0.60 0.62 0.70 0.74
0.78 0.80 0.85 0.90 0.96 9 0.64 0.93 1.07 1.05 1.06 1.11 1.15 1.14
1.13 1.09 1.13 1.10 1.08 1.08 10 1.06 1.10 1.14 1.15 1.16 1.17 1.18
1.17 1.17 1.14 1.12 1.11 1.11 1.09
[0164]
11TABLE 11 250 F. Heating Step D.sub.max at stated imaging energy
density/mJcm.sup.-2 Example 84 89 95 102 110 119 130 144 160 181
209 245 298 379 C9 0.60 0.60 0.60 0.60 0.63 0.69 0.78 0.90 0.96
1.02 1.04 1.07 1.10 1.11 9 0.90 1.08 1.13 1.14 1.15 1.15 1.15 1.15
1.15 1.15 1.12 1.09 1.07 1.06 10 1.14 1.16 1.17 1.19 1.19 1.19 1.21
1.21 1.21 1.20 1.18 1.15 1.14 1.11
[0165]
12TABLE 12 260 F. Heating Step D.sub.max at stated imaging energy
density/mJcm-2 Example 84 89 95 102 110 119 130 144 160 181 209 245
298 379 C9 0.60 0.59 0.59 0.60 0.67 0.76 0.87 1.04 1.11 1.16 1.17
1.17 1.17 1.19 9 1.11 1.18 1.22 1.23 1.23 1.24 1.27 1.27 1.29 1.26
1.21 1.19 1.19 1.16 10 1.14 1.16 1.18 1.18 1.18 1.19 1.18 1.18 1.18
1.18 1.16 1.14 1.14 1.14
[0166]
13TABLE 13 270 F. Heating Step D.sub.max at stated imaging energy
density/mJcm.sup.-2 Example 84 89 95 102 110 119 130 144 160 181
209 245 298 379 C9 0.61 0.61 0.61 0.68 0.76 0.90 1.01 1.14 1.21
1.21 1.22 1.20 1.17 1.21 9 1.14 1.17 1.17 1.16 1.15 1.15 1.15 1.14
1.14 1.14 1.15 1.16 1.15 1.16 10 1.17 1.20 1.22 1.23 1.23 1.23 1.23
1.23 1.22 1.21 1.20 1.20 1.20 1.18
[0167] Tables 9 to 13 show that:
[0168] (1) Addition of sulfonic acid as a sub layer (laid down
immediately before the application of the imaging layer) reduces
the amount of imaging energy required to achieve an exposed
negative working coating; and
[0169] (2) Increasing temperature of the heating stage also reduces
the amount of imaging energy required to achieve an exposed
negative working coating.
Examples 11 and 12
[0170] Example 11 was prepared as described in example 9 and
example 12 as in example 10, except that the imaging layer was
applied to the sulfonic acid sub layer after 48 hours. The results
can be seen in Tables 14 to 18 below:
14TABLE 14 230 F. Heating Step D.sub.max at stated imaging energy
density/mJcm.sup.-2 Example 84 89 95 102 110 119 130 144 160 181
209 245 298 379 11 0.59 0.59 0.59 0.60 0.60 0.65 0.72 0.74 0.77
0.84 0.82 0.85 0.89 0.95 12 0.79 0.82 0.78 0.88 0.98 1.03 1.06 1.06
1.06 1.03 1.00 1.00 0.99 0.97
[0171]
15TABLE 15 240 F. Heating Step D.sub.max at stated imaging energy
density/mJcm.sup.-2 Example 84 89 95 102 110 119 130 144 160 181
209 245 298 379 11 0.67 0.73 0.87 0.87 0.93 1.04 1.10 1.13 1.13
1.12 1.09 1.10 1.11 1.11 12 0.85 1.03 1.10 1.12 1.11 1.12 1.12 1.11
1.11 1.11 1.12 1.13 1.10 1.09
[0172]
16TABLE 16 250 F. Heating Step D.sub.max at stated imaging energy
density/mJcm.sup.-2 Example 84 89 95 102 110 119 130 144 160 181
209 245 298 379 11 1.08 1.12 1.17 1.18 1.18 1.18 1.18 1.18 1.18
1.16 1.16 1.16 1.15 1.15 12 1.11 1.15 1.15 1.16 1.17 1.18 1.18 1.19
1.19 1.19 1.18 1.18 1.17 1.18
[0173]
17TABLE 17 260 F. Heating Step D.sub.max at stated imaging energy
density/mJcm.sup.-2 Example 84 89 95 102 110 119 130 144 160 181
209 245 298 379 11 1.13 1.17 1.20 1.21 1.22 1.22 1.23 1.24 1.22
1.21 1.18 1.18 1.18 1.17 12 1.11 1.16 1.18 1.19 1.20 1.20 1.20 1.21
1.20 1.19 1.17 1.15 1.16 1.17
[0174]
18TABLE 18 270 F. Heating Step D.sub.max at stated imaging energy
density/mJcm.sup.-2 Example 84 89 95 102 110 119 130 144 160 181
209 245 298 379 11 1.18 1.18 1.20 1.20 1.20 1.19 1.18 1.19 1.18
1.17 1.17 1.18 1.17 1.17 12 1.15 1.18 1.19 1.19 1.20 1.21 1.21 1.20
1.19 1.18 1.18 1.19 1.18 1.19
[0175] Tables 14 to 18 show that:
[0176] (1) The sulfonic acid sub layer maybe laid down at a
substantially different time to the application of the imaging
layer, without deleterious effect on plate performance (for
example, compare Table 17 with Table 12); and
[0177] (2) Increasing temperature of the heating stage again
reduces the amount of imaging energy required to achieve an exposed
negative working coating.
Examples C13, 14 and 15
[0178] Example C13 was prepared as described in example C9, example
14 as in example 10 and example 14 as in example 11, except that
plate samples were aged in an environmental cabinet (80% RH, 104F.)
for 7 days prior to imaging, pre-heating and processing. After
processing these aged plates were also read via the Gretag
densitometer. The results can be seen in Tables 19 to 23.
19TABLE 19 230 F. Heating Step D.sub.max at stated imaging energy
density/mJcm.sup.-2 Example 84 89 95 102 110 119 130 144 160 181
209 245 298 379 C13 0.60 0.60 0.60 0.61 0.60 0.60 0.61 0.61 0.60
0.60 0.61 0.63 0.65 0.67 14 0.60 0.60 0.61 0.61 0.61 0.61 0.61 0.61
0.61 0.61 0.61 0.62 0.62 0.64 15 0.61 0.61 0.61 0.61 0.61 0.61 0.61
0.62 0.61 0.64 0.66 0.66 0.66 0.67
[0179]
20TABLE 20 240 F. Heating Step D.sub.max at stated imaging energy
density/mJcm.sup.-2 Example 84 89 95 102 110 119 130 144 160 181
209 245 298 379 C13 0.60 0.60 0.60 0.60 0.62 0.67 0.78 0.83 0.85
0.88 0.90 0.91 0.96 0.97 14 0.61 0.62 0.66 0.75 0.85 0.90 0.93 0.96
0.97 0.98 0.98 0.99 1.01 1.05 15 0.61 0.63 0.67 0.69 0.74 0.76 0.75
0.77 0.83 0.85 0.86 0.90 0.93 0.93
[0180]
21TABLE 21 250 F. Heating Step D.sub.max at stated imaging energy
density/mJcm.sup.-2 Example 84 89 95 102 110 119 130 144 160 181
209 245 298 379 C13 0.61 0.61 0.63 0.74 0.88 0.94 0.98 1.02 1.04
1.06 1.13 1.14 1.16 1.16 14 0.75 0.87 0.93 0.96 1.03 1.07 1.11 1.14
1.18 1.18 1.18 1.18 1.17 1.17 15 0.68 0.75 0.80 0.80 0.83 0.85 0.87
0.89 0.94 0.96 1.01 1.00 1.05 1.07
[0181]
22TABLE 22 260 F. Heating Step D.sub.max at stated imaging energy
density/mJcm.sup.-2 Example 84 89 95 102 110 119 130 144 160 181
209 245 298 379 C13 0.62 0.68 0.78 0.88 0.97 1.05 1.08 1.12 1.13
1.16 1.20 1.20 1.20 1.20 14 1.01 1.07 1.12 1.19 1.21 1.24 1.27 1.29
1.30 1.29 1.32 1.31 1.30 1.30 15 0.91 0.93 0.93 0.95 0.98 0.99 1.01
1.03 1.06 1.08 1.11 1.14 1.17 1.17
[0182]
23TABLE 23 270 F. Heating Step D.sub.max at stated imaging energy
density/mJcm.sup.-2 Example 84 89 95 102 110 119 130 144 160 181
209 245 298 379 C13 0.73 0.93 1.03 1.06 1.08 1.08 1.12 1.18 1.26
1.30 1.32 1.35 1.37 1.37 14 1.11 1.16 1.26 1.27 1.28 1.31 1.35 1.36
1.37 1.36 1.36 1.33 1.33 1.33 15 1.12 1.16 1.16 1.15 1.17 1.18 1.20
1.20 1.23 1.26 1.26 1.29 1.28 1.29
[0183] Tables 19 to 23 show that:
[0184] (1) The aging test slows all the plate samples down (i.e.
more imaging energy is required to achieve an exposed negative
working coating) but the sulfonic acid sub layer is not slowed any
more or less especially, than the control;
[0185] (2) Increasing temperature of the heating stage again
reduces the amount of imaging energy required to achieve an exposed
negative working coating with the aged plates; and
[0186] (3) The presence of the sulfonic acid sub layer allows
improves image density at lower pre-heat temperatures.
Examples 15 and 16
[0187] Example 15 was prepared as described in example 11 and
example 16 as in example 12, except that plate samples were aged in
an environmental cabinet (80% RH, 104.degree. F.) for 7 days prior
to imaging, pre-heating and processing. After processing these aged
plates were also read via the Gretag densitometer. The results can
be seen in Tables 24 to 28.
24TABLE 24 230 F. Heating Step D.sub.max at stated imaging energy
density/mJcm.sup.-2 Example 84 89 95 102 110 119 130 144 160 181
209 245 298 379 15 0.63 0.63 0.64 0.63 0.63 0.62 0.63 0.62 0.62
0.62 0.63 0.66 0.65 0.65 16 0.60 0.60 0.60 0.60 0.60 0.60 0.61 0.60
0.60 0.60 0.61 0.66 0.68 0.68
[0188]
25TABLE 25 240 F. Heating Step D.sub.max at stated imaging energy
density/mJcm.sup.-2 Example 84 89 95 102 110 119 130 144 160 181
209 245 298 379 15 0.60 0.60 0.60 0.61 0.63 0.65 0.72 0.74 0.79
0.81 0.83 0.85 0.90 0.91 16 0.62 0.64 0.70 0.72 0.80 0.86 0.91 0.98
1.00 1.02 1.03 1.06 1.08 1.05
[0189]
26TABLE 26 250 F. Heating Step D.sub.max at stated imaging energy
density/mJcm.sup.-2 Example 84 89 95 102 110 119 130 144 160 181
209 245 298 379 15 0.68 0.74 0.77 0.81 0.80 0.85 0.87 0.91 0.99
1.02 1.06 1.07 1.12 1.16 16 0.81 0.95 1.00 1.04 1.09 1.12 1.13 1.18
1.18 1.21 1.24 1.22 1.17 1.17
[0190]
27TABLE 27 260 F. Heating Step D.sub.max at stated imaging energy
density/mJcm.sup.-2 Example 84 89 95 102 110 119 130 144 160 181
209 245 298 379 15 0.95 0.99 1.02 1.03 1.03 1.05 1.08 1.14 1.16
1.18 1.20 1.24 1.24 1.24 16 1.20 1.23 1.25 1.27 1.29 1.30 1.35 1.36
1.38 1.42 1.41 1.41 1.41 1.41
[0191]
28TABLE 28 270 F. Heating Step D.sub.max at stated imaging energy
density/mJcm.sup.-2 Example 84 89 95 102 110 119 130 144 160 181
209 245 298 379 15 1.12 1.13 1.14 1.17 1.20 1.20 1.22 1.23 1.27
1.29 1.31 1.32 1.31 1.29 16 1.28 1.33 1.35 1.37 1.40 1.44 1.43 1.45
1.47 1.48 1.46 1.49 1.49 1.49
[0192] Tables 24 to 28 show that:
[0193] (1) The aging test slows all the plate samples down
(comparing Table 26 to 16, for example); and
[0194] (2) Increasing temperature of the heating stage again
reduces the amount of imaging energy required to achieve an exposed
negative working coating with the aged plates.
[0195] The present invention has been described with particular
reference to the preferred embodiments. It should be understood
that variations and modifications thereof can be devised by those
skilled in the art without departing from the spirit and scope of
the present invention. Accordingly, the present invention embraces
all such alternatives, modifications and variations that fall
within the scope of the appended claims.
* * * * *