Lithographic printing plate requiring no fountain solution

A lithographic printing plate requiring no fountain solution comprising a substrate having thereon a silicone rubber layer, wherein the silicone rubber layer comprises (A) 100 parts by weight of a linear diorganopolysiloxane having a trialkoxysilyl group at least at both ends, and (B) 0.1 to 50 parts by weight of a condensation catalyst.

FIELD OF THE INVENTION 
The present invention relates to a lithographic printing plate requiring no 
fountain solution comprising a substrate having thereon a silicone layer 
in which a coating solution for the silicone layer is excellent in aging 
stability. 
BACKGROUND OF THE INVENTION 
Various lithographic printing plates requiring no fountain solution for 
performing lithographic printing using no fountain solutions have been 
proposed. In particular, plates comprising a substrate having thereon a 
photosensitive layer and an ink-repellent layer have excellent 
characteristics. For example, various plates, such as positive, negative, 
ink-repellent upper layer, and ink-repellent lower layer types, have been 
proposed. Specifically, the positive ink-repellent upper layer type plates 
are described in JP-B-44-23042 (the term "JP-B" as used herein means an 
"examined Japanese patent publication") and JP-B-54-26923, and the 
positive ink-repellent lower layer type plates are described in 
JP-A-64-74541 (the term "JP-A" as used herein means an "unexamined 
published Japanese patent application") and JP-A-1-149043. Furthermore, 
the negative ink-repellent upper layer type plates are described in 
JP-B-46-16044, JP-B-61-54222 and JP-A-63-88556, and the negative 
ink-repellent lower layer type plates are described in JP-B-47-2361, 
JP-B-56-14976 and JP-A-1-173027. With the recent progress of 
digitalization of the plate-making process, lithographic printing plates 
requiring no fountain solution comprising a substrate having thereon a 
photosensitive layer and an ink-repellent layer have been proposed. Plates 
comprising silicone rubber as the ink-repellent layer for use in such 
lithographic printing plates are described in, for example, JP-B-54-26923, 
JP-B-55-22781, JP-B-56-23150 and JP-A-2-236550. Plates comprising a 
fluorine resin as the ink-repellent layers are described in, for example, 
JP-A-58-215411 and JP-A-2-103047. Among them, silicone rubber is more 
preferably used from the viewpoint of ink repellency. 
The silicone rubber layer for use in the lithographic printing plates is 
usually obtained by partially crosslink-curing a polymer mainly comprising 
a polysiloxane skeleton with a crosslinking agent. The method for curing 
the silicone rubber layers includes a condensation method in which a 
polysiloxane having a hydroxyl group at both ends are crosslinked with a 
silane compound having at least 3 hydrolytic functional groups directly 
bonded to a silicon atom to form silicone rubber (e.g., JP-B-56-23150, 
JP-A-54-54702, JP-A-61-230151). 
However, when the condensation silicone rubber layer is prepared by using a 
highly reactive silane compound as the crosslinking agent, the 
crosslinking reaction proceeds in the solution state because of the 
moisture in the air, resulting in gelation of a coating solution for the 
silicone rubber layer within several hours after solution preparation. 
Furthermore, when a less reactive silane compound is used as the 
crosslinking agent, it is disadvantageous because the silicone rubber 
layer is poor in curing characteristics after coating. 
SUMMARY OF THE INVENTION 
Therefore, an object of the invention is to provide a lithographic printing 
plate requiring no fountain solution comprising a silicone rubber layer 
having good characteristics which is provided by applying a coating 
solution for a condensation silicone rubber layer having sufficient aging 
stability, and crosslinking-curing it. 
This and other objects of the present invention have been attained by a 
lithographic printing plate having no fountain solution comprising a 
substrate having thereon a silicone rubber layer, wherein the silicone 
rubber layer comprises (A) 100 parts by weight of a linear 
diorganopolysiloxane having a trialkoxysilyl group at least at both ends, 
and (B) 0.1 to 50 parts by weight of a condensation catalyst (hereinafter 
referred to as "the waterless lithographic printing plate of the present 
invention"). 
DETAILED DESCRIPTION OF THE INVENTION 
The present invention will be illustrated in detail below. 
The waterless lithographic printing plate of the present invention has a 
silicone layer and a sensitive material layer. Examples of the sensitive 
material layer include various layers such as a photosensitive layer and a 
thermal-sensitive layer, and primer layers may be provided just on the 
substrate if necessary. 
The silicone layer of the present invention is described. 
Silicone Rubber Layer: 
In the present invention, a condensation silicone rubber provided by curing 
a composition comprising the following components (A) and (B) in the 
following ratio is used as the silicone rubber layer. 
Composition: 
(A) 100 parts by weight of a linear diorganopolysiloxane having 
trialkoxysilyl group at least at both ends (number average molecular 
weight: 3,000 to 1,000,000); 
(B) 0.1 to 50 parts by weight of a condensation catalyst. 
The progress of the crosslinking reaction in the coating solution for the 
silicone rubber layer can be inhibited by using the composition containing 
the above components in the above ratio. As a result, a sufficiently 
stable coating solution can be provided, and the silicone rubber layer 
which is excellent in curing characteristics of a coated film can be 
provided. If the component (B) is less than 0.1 parts by weight, the 
curing characteristics of the coated film are deteriorated; on the other 
hand, the component (B) is more than 50 parts by weight, the coating 
solution is gelled within several hours. 
Component (A) (Linear diorganopolysiloxane having trialkoxysilyl groups at 
least at both ends): 
The diorganopolysiloxane of the component (A) for use in the present 
invention is preferably represented by the following formula (I): 
##STR1## 
In formula (I), R.sup.1 represents a methyl group, an ethyl group or a 
propyl group, preferably a methyl group in terms of the curing 
characteristics; and R.sup.2 and R.sup.3 each represents an unsubstituted 
or substituted alkyl, alkenyl or aryl group having 1 to 10 carbon atoms. 
Furthermore, the diorganopolysiloxane of component (A) may be either a 
homopolymer having the same repeating unit or a copolymer containing the 
different repeating units in which R.sup.2 and R.sup.3 are different. In 
terms of ink repellency, however, it is preferred that 60% or more of 
R.sup.2 and R.sup.3 are a methyl group, a vinyl halide group, or a phenyl 
halide group. X and Y each represents an unsubstituted or substituted 
alkyl, alkenyl or aryl group having 1 to 10 carbon atoms, or a group 
represented by the following formula (II) or (III). X and Y may be the 
same or different, but at least one of X and Y is selected from the 
following formula (II) or (III): 
##STR2## 
In formula (III), R.sup.4 is an unsubstituted or substituted alkyl, alkenyl 
or aryl group having 1 to 10 carbon atoms. In formula (I), m is an integer 
of 5 or more, and n is an integer of 0 or more. In formulas (II) and 
(III), p is an integer of 0 or more. In formulas (I) and (II), L is a 
divalent connecting group, such as --O-- or an unsubstituted or 
substituted alkylene group having 1 to 10 carbon atoms. The plurality of 
R.sup.1, R.sup.2, R.sup.3, R.sup.4, X, Y, and L may be the same or 
different. The number average molecular weight of component (A) is 3,000 
to 1,000,000, more preferably 5,000 to 200,000. If it is less than 3,000, 
the coated film is markedly hard, resulting in poor press life and ink 
repellency. If it is more than 1,000,000, the curing characteristics of 
the coated film are poor. 
Component (B) (Condensation catalyst): 
The condensation catalyst for use in the present invention can be selected 
from known catalysts such as carboxylates of metals (for example, tin, 
titanium, zinc, lead, calcium, manganese, e.g., dibutyltin acetate, 
dibutyltin octylate, dibutyltin laurate, tetrabutyl titanate, 
tetra-2-ethylhexyl titanate, triethanolamine titanate, tetraisopropenyloxy 
titanate, lead octylate, lead naphthenate), and chloroplatinic acid. 
These components (B) may be used either alone or as a combination of two or 
more of them. The content thereof is 0.1 to 50 parts by weight, preferably 
0.5 to 10 parts by weight, based on 100 parts by weight of component (A). 
Other components: 
The silicone rubber layer may contain an alkoxysilane compound represented 
by the following formula (IV) or an oligomer provided by condensation of 2 
to 10 molecules thereof, if necessary. 
EQU (R.sup.5).sub.u.Si.(OR.sup.6).sub.v (IV) 
wherein R.sup.5 represents an alkyl, alkenyl or aryl group having 1 to 10 
carbon atoms; R.sup.6 represents a methyl group, an ethyl group or a 
propyl group; and u and v are an integer of 0 to 4, with the proviso that 
u+v is 4, and v represents an integer of 2 or more. v is preferably 3 or 
more, and more preferably 3. Examples of the alkoxysilane compound include 
tetramethoxysilane, methyltrimethoxysilane, isobutyltrimethoxysilane, 
decyltrimethoxysilane, vinyltrimethoxysilane, phenyl trimethoxysilane, 
dimethyldimethoxysilane, diphenyldimethoxysilane, tetraethoxysilane, 
methyltriethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane, 
dimethyldiethoxysilane, diphenyldiethoxysilane, tetrapropoxysilane, 
methyltripropoxysilane, vinyltripropoxysilane, phenyltripropoxysilane, 
dimethyldipropoxysilane and diphenyldipropoxysilane. Examples of the 
oligomer provided by condensation of 2 to 10 molecules thereof include 
oligomers represented by the following formulae (V) to (IX). Furthermore, 
partially hydrolyzed products thereof also give the same effect. However, 
they are not limited thereto. 
##STR3## 
By adding the alkoxysilane or the oligomer thereof, the aging stability of 
the coating solution for the silicone rubber layer, and the curing 
characteristics of the coated film can be improved. 
Furthermore, inorganic fine powders (e.g., silica, calcium carbonate, 
titanium oxide), adhesive auxiliaries (e.g., silane coupling agents, 
titanate coupling agents, aluminum coupling agents), photopolymerization 
initiators, aromatic group-substituted polydimethylsiloxanes (as disclosed 
in JP-A-1-179047) and silicone oil may be added. 
Coating solvent: 
Coating solvent for the silicone rubber layers for use in the present 
invention include aliphatic hydrocarbons such as pentane, hexane, heptane, 
"Isopar E, G, H" (manufactured by Esso Chemical Co., Ltd.), gasoline and 
kerosine. Furthermore, a high polar solvent can also be added within a 
limit of 20 parts by weight to the above solvents mainly composed of 
aliphatic hydrocarbons. Examples of the high polar solvent include water, 
alcohols, esters, ketones, ethers, aromatic hydrocarbons and carboxylic 
acids. 
The silicone rubber layer of the present invention can be obtained by 
forming the coated film by using the coating solution containing the 
coating solvent and above-mentioned components, and drying the coated 
films. The drying is preferably conducted at 50 to 170.degree. C. for 30 
seconds to 5 minutes. 
If the thickness of the silicone rubber layer for use in the present 
invention is too thin, the ink repellency is decreased so as to cause easy 
development of scratches. On the other hand, if the thickness is too 
thick, the developing characteristics are deteriorated. The thickness is 
therefore preferably 0.5 to 5 g/m.sup.2, and more preferably 1 to 3 
g/m.sup.2. 
In the waterless lithographic printing plates of the present invention, 
various ink-repellent layers may be coated on the silicone rubber layer. 
Furthermore, an intermediate layer may be provided between the sensitive 
material layer and the silicone rubber layer for enhancing the adhesive 
force between the sensitive material layer and the silicone rubber layer 
or preventing poisoning of the catalyst contained in the silicone rubber 
layer composition. 
Cover film: 
In order to protect a surface of the silicone rubber layer, the silicone 
rubber layer may be laminated with a transparent film such as 
polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, 
polyvinyl alcohol, polyethylene terephthalate and cellophane films, or may 
be coated with polymers. Oriented films may be used as such films. 
Furthermore, the matte treatment may be applied to these films to improve 
the vacuum adhesion to printing frames in image exposing, and contact 
faces of the films with the silicone rubber layers may be coated in order 
to improve the separating property thereof. 
Next, the substrate for use in the present invention is explained. 
Substrate: 
The waterless lithographic printing plate solution of the present invention 
has such pliability as to be set on an ordinary printing machine and at 
the same time withstand the printing pressure in printing. Accordingly, 
examples of the substrate for use in the present invention include coated 
paper, metal plates such as an aluminum plate, plastic films such as a 
polyethylene terephthalate film, rubber and composites thereof (e.g., 
paper sandwiched between a pair of aluminum sheets). Preferred substrates 
are aluminum and aluminum alloys, such as alloys of aluminum with silicon, 
copper, manganese, magnesium, chromium, zinc, lead, bismuth or nickel. 
Before an aluminum plate is used as a substrate, the plate is subjected to 
degreasing by showering or dipping in an aqueous acid solution in order to 
remove rolling oil from its surface. While any of acids known as 
degreasing agents for metals may be used, sulfuric acid or phosphoric acid 
is preferred. The acid processing is preferably followed by washing with 
water for an appropriate time. If desired, the degreased aluminum plate 
may be subjected to surface processing, such as graining, anodizing, or 
processing with an aqueous solution of silicate, e.g., sodium silicate or 
potassium silicate (that is, silicate processing). Among these, the 
silicate processing is preferred. In order to improve adhesion to a 
coating film, the substrate may be further processed with a silane 
coupling agent. 
In the waterless lithographic printing plate of the present invention, a 
primer layer may coated just on the substrate. Next, the primer layer is 
explained below. 
Primer Layer: 
If desired, a primer layer may be provided between a substrate and a 
photosensitive layer. As a primer layer for use in the present invention, 
various primers can be selected for particular purposes, such as 
improvement of adhesion between a substrate and a photosensitive layer, 
antihalation, dyeing of an image area, and improvement of printing 
characteristics. Examples of the primer layer include a layer formed by 
applying a photosensitive polymer of various kinds and exposing the 
polymer to cure before forming a photosensitive layer as disclosed in 
JP-A-60-22903; a layer formed by thermosetting an epoxy resin as disclosed 
in JP-A-62-50760; a layer formed by hardening gelatin as disclosed in 
JP-A-63-133151; a layer formed by using a urethane resin and a silane 
coupling agent as disclosed in JP-A-3-200965; and a layer formed by using 
a urethane resin disclosed in JP-A-3-273248. A hardened film of gelatin or 
casein is also effective as a primer layer. To soften a primer layer, the 
above-mentioned primer layer may contain a polymer having a glass 
transition point of room temperature or less, such as polyurethane, 
polyamide, styrene-butadiene rubber, carboxy-modified styrene-butadiene 
rubber, acrylonitrile-butadiene rubber, carboxy-modified 
acrylonitrile-butadiene rubber, polyisoprene, acrylate rubber, 
polyethylene, chlorinated polyethylene or chlorinated polypropylene. The 
amount added of the polymer is arbitrary. It is possible to form a primer 
layer solely of these polymers as long as the coating solution has 
film-forming properties. The primer layer may further contain various 
additives meeting the above-mentioned purposes, for example dyes, pH 
indicators, printing-out agents, photopolymerization initiators, adhesion 
assistants (e.g., polymerizable monomers, diazo resins, silane coupling 
agents, titanate coupling agents, aluminum coupling agents), pigments 
(e.g., titanium dioxide), and silica powder. The primer layer may be 
hardened or cured on exposure to light after application. The primer layer 
is applied to a dry thickness of from 0.1 to 20 g/m.sup.2, preferably from 
1 to 10 g/m.sup.2. 
Then, the sensitive material layer is described. The sensitive material 
layer for use in the present invention includes a photosensitive layer and 
a thermal-sensitive layer. First, the photosensitive layer and the 
developing method thereof are illustrated. 
Photosensitive layer: 
The photosensitive layer for use in the present invention may be any 
photosolubilization-photosensitive layers or 
photoinsolubilaization-photosensitive layers, as long as they produce 
changes in solubility in developing solutions and in adhesive force to the 
silicone rubber layer before and after exposure. Specifically, examples of 
the photosolubilization-photosensitive layers include photosensitive 
layers comprising an o-quinoneazide compound, an o-nitrobenzylcarbinol 
ester compound usually used in positive presensitized (PS) plates, wipe-on 
plates, and photoresists; photosensitive layers comprising a complex of a 
diazo compound with an inorganic or organic acid; and photosensitive 
layers comprising an acid-generating agent and a compound having an 
acid-decomposable group. Furthermore, photoseparation-photosensitive 
layers are also used which are obtained by crosslinking the 
photosolubilization-photosensitive compound with a multifunctional 
compound to make them slightly soluble or insoluble in the developing 
solution. 
The photoinsolubilization-photosensitive layers include photopolymerizable 
photosensitive layers, photo-crosslinking photosensitive layers and 
photosensitive layers comprising a diazo resin and a binder resin. 
The o-quinoneazide compound is a compound having at least one 
o-quinonediazido group, preferably at least one o-benzoquinonediazido 
group or o-naphthoquinonediazido group, and includes known compounds 
having various structures, for example, compounds described in J. Coser, 
Light Sensitive Systems, pages 339 to 353, John Wiley and Sons (1965). For 
example, they include esters of various hydroxyl compounds and 
benzoquinone-1,2-diazidosulfone, naphthoquinone-1,2-diazidosulfone, or 
other sulfonates. The hydroxyl compounds include condensed resins of 
phenols such as phenol, cresol and pyrogallol and carbonyl 
group-containing compounds such as formaldehyde, benzaldehyde and acetone, 
particularly resins obtained by condensation in the presence of acidic 
catalysts. 
Examples of the complex of a diazo compound with inorganic or organic acid 
include a photosensitive complex of diazophenylamine and phosphotungstic 
acid. 
Of the photosensitive layers containing a acid-generating agent and a 
compound having an acid-decomposable group, the compound having an 
acid-decomposable group include o-carboxylic acids and acetal. These 
photosensitive layer compositions are described in, for example, U.S. Pat. 
Nos. 4,101,323, 4,247,611, and 4,311,782. 
The photopolymerizable photosensitive layer of the present invention 
comprises at least (1) a monomer, oligomer or macromonomer each having at 
least one photopolymerizable ethylenic unsaturated group, (2) a 
photopolymerization initiator, and (3) a film-formable polymer. 
Component (1): Monomer, oligomer or macromonomer each containing at least 
one photopolymerizable ethylenic unsaturated group: 
Examples of the monomer, oligomer and macromonomer include 
(1) acrylic or methacrylic acid esters of alcohols (for example, ethanol, 
propanol, hexanol, 2-ethylhexanol, glycerine, hexanediol, 
trimethylolpropane, pentaerythritol, sorbitol, triethylene glycol, 
(poly)ethylene glycol, (poly)propylene glycol; ethylene oxide, propylene 
oxide or their mixed adducts of, e.g., glycerine, hexanediol, 
trimethylolpropane, pentaerythritol, sorbitol); 
(2) reaction products of amines (for example, ethylamine, butylamine, 
benzylamine, ethylenediamine, hexamethylenediamine, diethylenetriamine, 
xylylenediamine, ethanolamine, aniline, oxyethylenediamines 
oxypropylenediamines described in JP-A-6-118629, and adducts of 
xylylenediamine and ethylene oxide described in Japanese Patent 
Application No. 6-328730) and glycidyl acrylate, glycidyl methacrylate or 
allylglycidyl; 
(3) reaction products of carboxylic acids (for example, acetic acid, 
propionic acid, benzoic acid, acrylic acid, methacrylic acid, succinic 
acid, maleic acid, phthalic acid, tartaric acid and citric acid) and 
glycidyl acrylate, glycidyl methacrylate or allylglycidyl; 
(4) amide derivatives (for example, acrylamide, N-methylolacrylamide, 
t-butylacrylamide, methylenebisacrylamide, diacetoneacrylamide, 
xylylenediacrylamide); and 
(5) styrene derivatives (for example, p-hydroxystyrene, p-methylolstyrene). 
More specifically, they include urethane acrylates described in 
JP-B-48-41708, JP-B-50-6034 and JP-A-51-37193; polyester acrylates 
described in JP-A-48-64183, JP-B-49-43191 and JP-B-52-30490; 
multifunctional acrylates and methacrylates such as epoxy (meth)acrylates 
obtained by reacting epoxy resins with (meth)acrylic acids; and 
N-methylolacrylamide derivatives described in U.S. Pat. No. 4,540,649. 
Further, photocurable monomers and oligomers described in Nippon 
Setchaku-zai Kyokaishi, 20(7):300-308 (1984) and macromonomers described 
in Dreyfuss, P. & Quirk, R. P., Encycl. Polym. Sci. Eng., 7:551 (1987), 
Kagaku Kogyo, 38:56 (1987) and Kobunshi Kakoh, 35:262 (1986) can also be 
used. However, they are not limited thereto, and in the multifunctional 
monomers, unsaturated groups may exist as mixtures of acrylic, 
methacrylic, allyl, and vinyl groups. Furthermore, they may be used alone 
or in combination. The amount thereof used is 5 to 80 parts by weight, 
preferably 30 to 70 parts by weight, based on the total solid weight of 
the photopolymerizable photosensitive layer. 
Component (2): Photopolymerizable initiator 
The photopolymerization initiator for use in the present invention can be 
selected from compounds, either sensitized or non-sensitized, capable of 
generating radicals through photolysis. Specific but non-limiting examples 
of photopolymerization initiators include: 
(a) benzophenone derivatives, such as benzophenone, 
dimethylaminobenzophenone, diethylaminobenzophenone, xanthone, anthrone, 
thioxanthone, acridone, 2-chloroacridone, 2-chloro-N-n-butylacridone, 
2,4-diethylthioxanthone, and fluorenone; 
(b) benzoin derivatives, such as benzoin, benzoin methyl ether, and benzoin 
ethyl ether; 
(c) quinones, such as p-benzoquinone, .beta.-naphthoquinone, and 
.beta.-methylanthraquinone; 
(d) sulfur compounds, such as dibenzyl disulfide and di-n-butyl disulfide; 
(e) azo or diazo compounds, such as 2-azobisisobutyronitrile, 
1-azo-bis-1-cyclohexanecarbonitrile, p-diazobenzylethylaniline, and Congo 
Red; 
(f) halogen compounds, such as carbon tetrachloride, silver bromide, 
.alpha.-chloromethylnaphthalene, trihalomethyl-s-triazine compounds, and 
trihalomethyloxadiazole compounds; and 
(g) peroxides, such as benzoyl peroxide. 
These initiators may be used either individually or as a combination of two 
or more thereof. The initiator is used in an amount of from 0.1 to 25%, 
preferably from 3 to 20%, by weight, based on all compositions in the 
photopolymerizable photosensitive layer. 
Component (3): Film-formable polymeric compound 
The film-formable polymeric compounds for use in the present invention 
include polymers or copolymers described below. (1) vinyl polymers, such 
as polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl 
methyl ether, polyvinyl chloride, polyethylene, and copolymers thereof; 
(2) (meth)acrylate polymers, alkyl(meth)acrylamide polymers, such as 
polyethyl (meth)acrylate, polybutyl (meth)acrylate, 
poly-t-butylacrylamide, polydiacetonacrylamide, and copolymers thereof; 
(3) unvulcanized rubber, such as natural rubber, polybutadiene, 
polyisobutylene, polyneoprene, and copolymers thereof; 
(4) polyethers, such as polyethylene oxide, and polypropylene oxide; 
(5) polyamides, such as copolymers of caprolactam, laurolactam, 
hexamethylenediamine, 4,4'-bis-aminocyclohexylmethane, 
2,4,4-trimethylhexamethylenediamine, isophoronediamine, diglycols, 
isophthalic acid, adipic acid and sebacic acid; 
(6) polyesters, such as a condensation product between terephthalic acid or 
adipic acid and ethylene glycol or 1,4-butanediol; and 
(7) polyurethanes, such as those obtained from hexamethylene diisocyanate, 
tolylene diisocyanate, naphthalene-1,5-diisocyanate or isophorone 
diisocyanate and ethylene glycol, 1,4-butanediol or polyester. 
Isophoronediamine or hexamethylenediamine may be used as a chain extender. 
Additionally, high polymers having a photopolymerizable or 
photo-crosslinkable olefinically unsaturated double bond on their side 
chain(s) can also be used as film-formable polymeric compounds. 
The above-mentioned polymeric compounds may be used either individually or 
as a combination of two or more thereof. They are used in an amount of 
from 10 to 90%, preferably from 25 to 75%, by weight based on all 
compositions in the photopolymerizable photosensitive layer. 
Other Components: 
In addition to the aforesaid components, a thermal polymerization inhibitor 
is preferably contained. Example thereof include hydroquinone, 
p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butyl catechol, 
4,4'-thiobis(3-methyl-6-t-butylphenol), 
2,2'-methylenebis(4-methyl-6-t-butylphenol), and 2-mercaptobenzimidazole. 
For the purpose of coloring the photopolymerizable photosensitive layer, 
the composition may contain a dye or a pigment or, as a printing-out 
agent, a pH indicator or a leuco dye. According to the end use, the 
composition may further contain a small amount of a silicone compound, 
such as polydimethylsiloxane, methylstyrene-modified polydimethylsiloxane, 
olefin-modified polydimethylsiloxane, polyether-modified 
polydimethylsiloxane, a silane coupling agent, silicone diacrylate, or a 
silicone dimethacrylate. A silicone surfactant or fluorine surfactant may 
be added for the improvement of coating properties. A diazo resin may be 
added for the improvement of adhesion of a photopolymerizable 
photosensitive layer and a primer layer. Further, a plasticizer for the 
improvement of softness (e.g., polyethylene glycol, polypropylene glycol, 
tricresyl phosphate) or a stabilizer (e.g., phosphoric acid) may be added. 
These additives are generally used in an amount of 10% or less by weight 
based on all compositions in the photopolymerizable photosensitive layer. 
Sometimes, hydrophobic silica powders having been processed with a 
(meth)acryloyl or allyl group-containing silane coupling agent may be 
added in an amount of 10% or less by weight based on all compositions in 
the photopolymerizable photosensitive layer. 
Furthermore, the photocrosslinking photosensitive layer include layers 
mainly comprising photosensitive polymers such as polyesters, polyamides 
and polycarbonates having --CH.dbd.CH--CO-- as a photosensitive group on 
the main chain or on side chains of the polymers. Examples thereof include 
photosensitive polyesters obtained by a poly-condensation reaction of 
phenylenediacrylic acid or esters thereof and a polyhydric alcohol as 
described in JP-B-55-22781 and JP-A-55-40415; vinyl polymers having a 
maleimido group at side chains thereof as described in JP-A-64-35547; 
(2-propenylidene)malonic acid compounds such as cinnamylidene-malonic acid 
as described in U.S. Pat. No. 2,956,878; and photosensitive polyesters 
derived from difunctional glycols. 
The diazo resin comprising diazo resins and binder resins for use in the 
photosensitive layer include condensation products of aromatic dizaonium 
salts and formaldehyde. Particularly preferred examples thereof include 
salts of condensation products of p-diazodiphenylamine and formaldehyde or 
acetaldehyde such as inorganic salts of diazo resins which are reaction 
products of hexafluorophosphates, tetrafluoroborates, perchlorates or 
periodates and the above-mentioned condensation products, and organic 
salts of diazo resins which are reaction products of the above-described 
condensation products and sulfonic acid derivatives as described in U.S. 
Pat. No. 3,200,309. In the present invention, the ratio of the diazo resin 
to the photosensitive layer is 20 to 95 parts by weight, and preferably 35 
to 80 parts by weight. 
Various high-molecular compounds can be used as the binder resin. However, 
preferred examples thereof include copolymers of a monomer having an 
aromatic hydroxyl group as described in JP-A-54-98613 (e.g., 
N-(4-hydroxyphenyl)-acrylamide, N-(4-hydroxyphenyl)methacrylamide, o-, m- 
or p-hydroxystyrene, o-, m- or p-hydroxyphenyl methacrylate) and other 
monomer; polymers containing a hydroxyethyl (meth)acrylate unit as a main 
repeating unit as described in U.S. Pat. No. 4,123,276; copolymer resins 
comprising a monomer unit having a phenolic hydroxyl group and a monomer 
unit having an alcoholic hydroxyl group as described in JP-A-3-158853; 
natural resins (e.g, shellac, rosin); polyvinyl alcohols; polyamide resins 
as described in U.S. Pat. No. 3,751,257; linear polyurethane resins as 
described in U.S. Pat. No. 3,660,097; phthalated polyvinyl alcohol resins; 
epoxy resins obtained by condensation of bisphenol A and epichlorohydrin; 
and cellulose derivatives (e.g., cellulose butylate, cellulose acetate). 
The photocrosslinking photosensitive layer and the photosensitive layer 
comprising the diazo resin may also contain additives such as dyes, 
surfactants, plasticizers, and stabilizers. 
The photosensitive layer composition for use in the present invention is 
dissolved in an appropriate solvent such as water, 2-methoxyethanol, 
2-methoxyethyl acetate, propylene glycol methylethyl acetate, methyl 
lactate, propylene glycol monomethyl ether, ethanol, methyl ethyl ketone, 
N,N-dimethylacetamide, methyl pyruvate, ethyl pyruvate and methyl 
3-methoxypropionate alone or in mixed solvents thereof, and coated on a 
substrate. The amount thereof coated after drying is preferably 0.1 to 20 
g/m.sup.2, and more preferably 0.5 to 10 g/m.sup.2. 
Development processing: 
The waterless lithographic printing plate of the present invention using 
the photosensitive layer described herein is exposed through a transparent 
original, and then developed with a developing solution which can partly 
dissolve or swell the photosensitive layer of image areas (unexposed 
areas). 
In the present invention, known developing solutions for waterless 
lithographic printing plates can be used as the developing solution. 
However, water or an aqueous solution of water-soluble organic solvent 
mainly comprising water is preferably used. Taking into account safety and 
inflammability, the concentration of the water-soluble solvent is 
preferably less than 40% by weight. Examples of the known solvents include 
aliphatic hydrocarbons (e.g., hexane, heptane, "Isopar E, G, H" 
(manufactured by Esso Kagaku Co.), gasoline, kerosine), aromatic 
hydrocarbons (e.g., toluene, xylene), and hydrocarbon halides (e.g., 
Trichlene) each containing the following polar solvents; and the following 
polar solvents. 
The polar solvents include alcohols (e.g., methanol, ethanol, propanol, 
isopropanol, benzyl alcohol, ethylene glycol monomethyl ether, 
2-ethoxyethanol, diethylene glycol monohexyl ether, triethylene glycol 
monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol 
monomethyl ether, polyethylene glycol monomethyl ether, polypropylene 
glycol, tetraethylene glycol), 
ketones (acetone, methyl ethyl ketone), 
esters (ethyl acetate, methyl lactate, butyl lactate, propylene glycol 
monomethyl ether acetate, diethylene glycol acetate, diethyl phthalate), 
and 
others (triethyl phosphate, tricresyl phosphate). 
In addition, a developing solution in which water is added to the organic 
solvent developing solution, a developing solution in which the organic 
solvent is solubilized in water by use a surfactant, and a developing 
solution in which an alkali agent (e.g., sodium carbonate, diethanolamine, 
sodium hydroxide) are further added thereto. 
Furthermore, dyes such as Crystal Violet, Victoria Pure Blue and Astrazone 
Red can be added to the developing solution to dye image areas 
simultaneously with development. 
The development can be conducted by known methods such as rubbing of plate 
faces with developing pads containing the developing solutions as 
described above, and rubbing of plate faces with developing brushes after 
pouring of the developing solutions on the plate faces. The temperature of 
the developing solution can be arbitrarily selected, but is preferably 
10.degree. C. to 60.degree. C. The development removes the silicone rubber 
layer of the image areas to convert the areas to ink-repellent areas. 
In order to confirm the thus obtained image forming characteristics of the 
printing plate, the exposed image area can be dyed with a dyeing solution 
to make the exposed image area detectable. When the developing solution 
does not contain the dye for dyeing the exposed image area, the area is 
treated with the dyeing solution after the development. Only the exposed 
image area of the photosensitive layer is dyed by softly rubbing the image 
area with a pad impregnated with the dyeing solution. It can be confirmed 
thereby whether the development is fully perplated to highlights or not. 
As the dyeing solution, a solution or a dispersion is used in which one or 
more dyes selected from water-soluble disperse dyes, acid dyes and basic 
dyes are dissolved or dispersed in a solvent such as water, alcohol, 
ketones or ethers, or in a mixed solvent of two or more of them. In order 
to improve the dye affinity, it is also effective to add carboxylic acids, 
amines, surfactants, dyeing auxiliaries, or antifoaming agents. 
The printing plate dyed with the dyeing solution is preferably washed with 
water, followed by drying, which can remove the dye adhered to a non-image 
area or the back of the plate and inhibit the stickiness of the plate 
surfaces, resulting in improvement in handling characteristics of the 
printing plate. 
When the thus treated printing plates are stored in piles, guard sheets are 
preferably inserted therebetween to protect the printing plates. 
It is preferred that the development processing, the dyeing processing, the 
subsequent washing and drying as described above are conducted with an 
automatic processor. A preferred example of such an automatic processor is 
described in JP-A-2-22061. 
Sensitive material layers other than photosensitive layer: 
The sensitive material layers other than the photosensitive layer which are 
used in the present invention include discharge ablation image formation 
conductive layers described in JP-B-40-21879, JP-A-50-106509, and 
JP-W-4-501684 (the term "JP-W" as used herein means an "unexamined 
published international patent application"); laser ablation image 
formation thermally sensitive layers described in JP-B-40-21879, 
JP-A-6-55723, and JP-A-6-186750; thermal transfer image formation 
thermally sensitive layers described in JP-A-2-292043, JP-A-4-126295, 
JP-A-4-151292, and JP-A-4-263994; and thermal fusion image formation 
thermally sensitive layers described in JP-B-4-73715 and JP-A-1-192555. 
The present invention is now illustrated in greater detail by way of the 
following examples, but it should be understood that the present invention 
is not to be construed as being limited thereto. In the following 
examples, all parts, percents, ratios and the like are by weight unless 
otherwise indicated.

EXAMPLES 1 TO 8 
Waterless lithographic printing plates were produced in the following 
manner. 
Primer layer: 
An aluminum plate of JIS A 1050 having a thickness of 0.3 mm was degreased 
by the usual method, and immersed in a 1% aqueous solution of KBM603 
(manufactured by Shin-Etsu Chemical Co. Ltd.), a silane coupling agent, 
followed by drying at room temperature. The aluminum plate was coated with 
the following coating solution to form primer layer to give a dry weight 
of 4 g/m.sup.2, and dried at 140.degree. C. for 2 minutes. 
______________________________________ 
Sanprene IB1700D 10 parts 
(produced by Sanyo Chemical Industries, 
Ltd.) 
Hexafluorophosphate of condensation 
0.1 parts 
product of p-diazodiphenylamine and 
paraformaldehyde 
TiO.sub.2 0.1 parts 
MFC323 0.03 parts 
(produced by Dainippon Ink and 
Chemicals, Inc.) 
Propylene glycol methyl ether acetate 
50 parts 
Methyl lactate 20 parts 
Pure water 1 part 
______________________________________ 
Then, the primer layer was exposed by 20 counts by using an FT26IV UDNS 
ULTRA-PLUS FLIPTOP PLATE MAKER vacuum exposing device manufactured by Nu 
Ark Company. 
Photosensitive layer: 
The aluminum plate on which the above primer layer was plated was coated 
with a photopolymerizable photosensitive solution having the following 
composition to give a dry weight of 3 g/m.sup.2, and dried at 120.degree. 
C. for 1 minute. 
______________________________________ 
Polyurethane resin (isophorone 
1.5 parts 
diisocyanate/polyester (adipic 
acid/1,4-butanediol/ethylene/ 
glycol)/isophoronediamine) 
Adduct of 1 mol of m-xylylene- 
1.5 parts 
diamine/4 mol of glycidyl 
methacrylate 
Sartomer 9035 (produced by 
0.3 parts 
Somar Co.) 
Polyethylene glycol (Mw = 400) 
0.05 parts 
Ethyl Michler's ketone 0.4 parts 
2,4-Diethylthioxanthone 0.05 parts 
9-Fluorenone 0.05 parts 
Aizen Victoria Blue BHconc 
0.01 parts 
(produced by Hodogaya Chemical 
Co., Ltd.) 
Fluorine surfactant (Megafac F177, 
0.01 parts 
manufactured by Dainippon Ink and 
Chemicals, Inc.) 
Methyl ethyl ketone 20 parts 
Propylene glycol monomethyl ether 
20 parts 
______________________________________ 
Silicone rubber layer: 
A condensation silicone rubber solutions having the following composition 
was prepared. Then, a 10 g sample was collected and allowed to stand to 
examine the gelation initiation time of the coating solutions. On the 
other hand, a 200 g sample was collected, and the viscosity of the coating 
solution was measured with stirring. The residual silicone rubber solution 
was applied over the above photopolymerizable photosensitive layer to give 
a dry weight of 2 g/m.sup.2, and dried at 130.degree. C. for 2 minutes. 
After drying, the degree of swelling of the cured silicone rubber layers 
with Isopar G (produced by Esso Chemical Co.) was measured. 
______________________________________ 
Polydimethylsiloxane having 
9 parts 
trialkoxysilyl groups at both ends 
shown in Table 1 
Condensation catalyst shown in Table 1 
(see Table 1) 
Alkoxysilane compound or oligomer 
(see Table 1) 
shown in Table 1 
Isopar G (produced by Esso 
120 parts 
Kagaku Co.) 
______________________________________ 
The thus obtained silicone rubber layer was laminated with a 12-.mu.m thick 
biaxial oriented polypropylene film one side so that the surface of the 
film not matted was brought into contact with the silicone rubber layer, 
thereby obtaining a waterless lithographic printing plate of the present 
invention. 
Comparative Examples 1 To 6 
Silicone rubber layer: 
After preparation of condensation type silicone rubber solutions having the 
following compositions, the gelation initiation time and the viscosity of 
the coating solutions, and the degree of swelling of the coated films were 
measured by the same methods as with Examples 1 to 8. 
______________________________________ 
.alpha., .omega.-Dihydroxypolydimethylsiloxane 
9 parts 
(the degree of polymerization: about 900) 
Dibutyltin octylate (see Table 1) 
Condensation crosslinking agent 
(see Table 1) 
shown in Table 1 
Isopar G (produced by Esso 
120 parts 
Chemical Co.) 
______________________________________ 
The thus obtained silicone rubber layer was laminated with a polypropylene 
film in the same manner as in Examples 1 to 8 to obtain a comparative 
waterless lithographic printing plate. 
TABLE 1 
______________________________________ 
Polydimethylsiloxane Condensation 
(a) (b) Condensation 
crosslinking 
Polymerization degree 
catalyst Agent 
700 500 900 (c) (d) (e) (f) (g) 
______________________________________ 
Example 1 
9.0 0 0 0.01 0 0 0 0 
Example 2 
9.0 0 0 0.02 0 0 0 0 
Example 3 
0 9.0 0 0.01 0 0 0 0 
Example 4 
4.5 4.5 0 0.01 0 0 0 0 
Example 5 
9.0 0 0 0 0.01 
0 0 0 
Example 6 
9.0 0 0 0.01 0 1 0 0 
Example 7 
9.0 0 0 0.01 0 2 0 0 
Example 8 
9.0 0 0 0.01 0 0 1 0 
Comp. 0 0 9.0 0.01 0 1 0 0 
Example 1 
Comp. 0 0 9.0 0.02 0 1 0 0 
Example 2 
Comp. 0 0 9.0 0.01 0 2 0 0 
Example 3 
Comp. 0 0 9.0 0.01 0 0 0 1 
Example 4 
Comp. 0 0 9.0 0.02 0 0 0 1 
Example 5 
Comp. 0 0 9.0 0.01 0 0 0 2 
Example 6 
______________________________________ 
Notes: 
(a): Trimethoxysilyl at both ends 
(b): Hydroxysilyl at both ends 
(c): Dibutyltin octylate 
(d): Tetrabutyl Titanate 
(e): Methyltrimethoxysilane 
(f): 3:7 Mixture of oligomers represented by formulas (VII) and (VIII) 
(g): Methyltriacetoxysilane 
For these printing plates, every sheet was superimposed on a positive film 
having a halftone dot image of 200 lines/inch and a gray scale (G/S) 
having a optical density difference of 0.15, and exposed by 20 counts by 
using an FT26IV UDNS ULTRA-PLUS FLIPTOP PLATE MAKER vacuum exposing device 
manufactured by Nu Ark Company. Then, the laminated film was peeled off, 
and immediately subjected to the following development processing. 
Development processing: 
The printing plates were immersed in water at 35.degree. C., and rubbed 
with a developing pad to remove the silicone rubber layers of the 
unexposed areas. Subsequently, the plates were dyed with a dyeing solution 
having the following composition, and the sensitivity (G/S clear 
sensitivity) and the dot reproduction (halftone dot area of reproducible 
highlights, unit: %) were evaluated. 
(Dyeing Solution) 
______________________________________ 
Crystal Violet 0.1 parts 
Diethylene Glycol Monoethyl Ether 
15 parts 
Pure Water 85 parts 
______________________________________ 
TABLE 2 
__________________________________________________________________________ 
Silicone 
Coating solution for silicone rubber layer 
rubber layer 
10 g, Still 200 g, Stirring sample 
coated film 
Pressing properties 
standing sample 
Solution viscosity (cps) 
lubrication 
Dot 
Gelation 
Just after degree reproduction 
Sample 
initiation time 
preparation 
After 10 hr 
(%) Sensitivity 
(%) 
__________________________________________________________________________ 
Example 1 
10 hr or more 
3.0 3.0 160 8 2 
Example 2 
10 hr or more 
3.0 3.0 155 8 2 
Example 3 
10 hr or more 
2.4 2.4 150 9 2 
Example 4 
10 hr or more 
2.7 2.7 155 8 2 
Example 5 
10 hr or more 
3.0 3.0 160 8 2 
Example 6 
10 hr or more 
3.0 3.0 160 8 2 
Example 7 
10 hr or more 
3.0 3.0 165 9 3 
Example 8 
10 hr or more 
3.0 3.0 155 8 2 
Comparative 
10 hr or more 
3.8 3.8 curing failed 
-- -- 
Example 1 
Comparative 
10 hr or more 
3.8 3.8 curing failed 
-- -- 
Example 2 
Comparative 
10 hr or more 
3.8 3.8 curing failed 
-- -- 
Example 3 
Comparative 
after 2 hr 
3.8 8.5 160 9 3 
Example 4 
Comparative 
after 1 hr 
3.8 8.9 150 9 3 
Example 5 
Comparative 
after 3 hr 
3.8 7.4 150 7 2 
Example 6 
__________________________________________________________________________ 
The results in Table 2 show that the waterless lithographic printing plates 
of the present invention are significantly improved in aging stability of 
the coating solutions for the silicone rubber layers while keeping good 
curing properties of the coated silicone rubber films, sensitivity and dot 
reproducibility. 
According to the present invention, gelation of the polysiloxanes caused by 
condensation in the coating solutions is inhibited, and the waterless 
lithographic printing plates excellent in aging stability of the coating 
solutions for the silicone rubber layers. 
While the invention has been described in detail and with reference to 
specific embodiments thereof, it will be apparent to one skilled in the 
art that various changes and modifications can be made therein without 
departing from the spirit and scope thereof.