JPH03180848A - Damping-waterless planographic printing original plate - Google Patents

Abstract

PURPOSE:To improve the sensitivity, image quality and scratch resistance of the above original plate by incorporating prescribed natural proteins into a primer layer. CONSTITUTION:The above original plate is formed by successively laminating a primer layer (A), a photosensitive resin layer and a silicone rubber layer on a base consisting of an Al sheet, etc. At least one kind of the natural proteins selected from casein (e.g. lactic acid casein), gelatin (e.g. photographic gelatin), soybean protein, and albumin and urethane elastomer (e.g. polyether type polyurethane latex) are incorporated into the layer A. A filler, dye for preventing halation, adhesive assistant, etc., may be added at need to the layer A.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to the production of a dampening water-free lithographic printing plate (hereinafter referred to as waterless lithographic printing plate) that is capable of printing without using dampening water. This invention relates to waterless lithographic printing plates.

[Prior art and problems to be solved] Various types of waterless lithographic plates have already been proposed in which a primer layer, a photosensitive resin layer, and a silicone rubber layer are sequentially provided on a support (for example, Japanese Patent Publication No. 44 -23042, Special Publication No. 1977-1
6044, Japanese Patent Publication No. 54-26923, Japanese Patent Publication No. 1983-
80046, Special Publication No. 55-22781, etc.).

In such a waterless lithographic printing plate, the non-image area has a surface made of ink-repellent silicone rubber, while the image area has at least a photosensitive resin layer or primer from which the silicone rubber layer has been removed. The layer has an exposed surface, and ink selectively adheres to and prints only on the areas where the silicone rubber layer has been removed.

However, the silicone rubber layer has low mechanical strength and
A thin layer is easily scratched when the plate is handled, and the ink-receiving areas in the lower layer are exposed, easily causing scratches and stains. On the other hand, when the silicone rubber layer is made thicker in order to increase the strength, the developability deteriorates and it becomes difficult to form fine lines and minute halftone dots in highlighted areas.

In order to improve this problem, according to JP-A-62-194255 and JP-A-1-172834, a primer layer made of epoxy resin or the like or a primer layer mainly composed of gelatin is coated thickly to a thickness of 6 to 100 μm. Although methods have been proposed to alleviate the stress exerted on the printing plate, these methods have not yet been fully satisfactory.

In addition, in a waterless lithographic plate in which a photosensitive resin layer and a silicone rubber layer are sequentially provided on a brimer layer made of a soft urethane elastomer, it has excellent scratch resistance due to the shock absorber effect of the urethane elastomer. The problem is that the elastomer partially dissolves depending on the coating solvent used for the photosensitive resin layer, causing spots on the surface of the photosensitive resin layer and greatly affecting the sensitivity and developability of the waterless lithographic printing plate. was there.

Therefore, as shown in JP-A-61-163343, it has been proposed to crosslink the urethane elastomer or provide an intermediate layer, but crosslinking hardens the elastomer and has the effect of improving scratch resistance. However, the results are still not completely satisfactory, such as a decrease in the amount of carbon dioxide and a complicated manufacturing process.

Therefore, an object of the present invention is to provide a waterless lithographic printing plate having high sensitivity, high image quality, and excellent scratch resistance.

Means for Solving the Problems> Natural proteins exhibit excellent resistance to almost all organic solvents, including ether, ester, and ketone organic solvents that are often used to form photosensitive resin layers. Therefore, the present inventors developed a waterless lithographic printing original plate in which a primer layer, a photosensitive resin layer, and a silicone rubber layer were sequentially provided on a support, and the primer layer contained (a) casein, gelatin, soybean protein, and albumin. By using a mixture of at least one natural protein selected from (b) a urethane elastomer,
It has been found that the above object can be achieved, and the present invention has been made based on this finding.

The present invention will be explained in detail below.

The natural protein (a) in the primer layer of the present invention is at least one protein selected from casein, gelatin, soybean protein, and albumin. Casein is the main component of milk protein and is not a single protein but a mixture of at least three similar proteins. Commercially available caseins include lactic acid casein, sulfate casein, hydrochloric acid casein, rennet casein, etc., depending on the industrial manufacturing method, and the quality and composition of casein differ depending on the manufacturing method. However, any casein, which is a natural polymer in which various amino acids are condensed, can be used.

Methods for dissolving casein include (1) adding it to ammonia water or a heated solution of alkaline soda salt;
2) There is a method in which an amide compound is added and dissolved in cold water, but in the method using ammonia, the ammonia evaporates after the primer layer is applied and dried, resulting in excellent water resistance of the coating film. Although the method using alkaline soda salt is inferior to the method using ammonia in water resistance, it is advantageous in that no ammonia odor is generated during coating. These can be mixed in various ways depending on the required performance.

As the gelatin, so-called photographic gelatin, which is obtained mainly from cow bones and hides by acid treatment or lime treatment, is used. However, any gelatin can be used as long as it is a natural polymer compound in which various amino acids are condensed. There are many types of amino acids that make up gelatin, and products with various compositions can be obtained depending on the purification conditions, and there are also considerable differences depending on the raw materials, but any of them can be used in the primer layer of the present invention.

In addition, natural proteins such as soybean protein (soybean casein) and albumin, which have chemical properties similar to casein, can also be used in the primer layer of the present invention.

The primer layer used in the present invention preferably contains 5 to 70% of the above natural protein in terms of solvent resistance and scratch resistance.

The urethane elastomer (〇) in the primer layer of the present invention has a 100% modulus of 100k as measured by the method described in Rubber Test Methods (edited by Japan Rubber Association), p. 233.
It is preferable that it is below g/ci.

100kg/cn! In the case of a primer layer containing more than 100% of the scratch resistance, the effect of improving scratch resistance is small.

Such a urethane elastomer ('b) in the primer layer of the present invention may contain, for example, 4,
4'-diphenylmethane diisocyanate, tolylene diisocyanate, naphthylene-l.

Using an organic diisocyanate such as 5-diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, or isophorone diisocyanate, using a polyhydric alcohol such as polyester glycol, polyether glycol, or polymer diol as a soft segment, Also, as a chain extender, ethylene glycol, 1,4
Examples include those synthesized using -butanediol, hexamethylene diamine, etc. under a catalyst such as triethylamine, triethylene diamine, or an organic tin compound.

Since the urethane elastomer (urethane elastomer, etc.) used in the present invention is mixed with the natural protein (a) and applied, it is preferable to emulsify and disperse it in water in advance. - As described in Handbook Ji pages 210 to 213 (1975), emulsification and dispersion can be carried out by several methods such as phase inversion emulsification method, blocked isocyanate method, prepolymer method, and self-emulsification method.

In the primer layer of the present invention, it is preferable to use a hardening agent for gelatin which is generally used in the photographic industry and is described in JP-A-63133153 in order to cross-link and harden natural proteins and strengthen water resistance. Furthermore, the primer layer of the present invention may contain a silane coupling agent.

The silane coupling agent has the effect of improving adhesive strength with the support and imparting water resistance to the primer layer. As the silane coupling agent, - those known for boat fishing, such as "Surface" Volume 21, 157-167
Page (1983) and E.P. Prudeman, “
Silane Coupling Agents” Blenheim Press (1982) [PIueddemann “5il
ane Coupling Agenjs″Plenu
mPress (1982)] can be used. In addition to silane coupling agents, titanate coupling agents and aluminum coupling agents can also be effectively used.

This primer layer may contain fillers such as titanium oxide, calcium carbonate, colloidal silica, and silicone resin powder, dyes and pigments to prevent halation, and adhesion aids (e.g., polymerizable monomers, diazo resins) as necessary.
etc. may be added. Further, a dye, a pH indicator, an acid generator, and a photopolymerization initiator for imparting print-out properties may be appropriately mixed and used.

The thickness of the primer layer is 0.1 to 50 μm, preferably 1
．． It is 0 to 20 μm. If the thickness is less than 0.1 μm, there will be little effect on scratch resistance, while if it is thicker than 50 μm, the drying load during production will increase, which tends to be economically disadvantageous.

As the support used in the present invention, any support can be used as long as it is flexible enough to be set in a common lithographic printing machine and can withstand the load applied during printing. For example, typical substrates include coated paper, metal plates such as aluminum, plastic films such as polyethylene terephthalate, or composites thereof.

The photosensitive resin layer used in the present invention is generally any material as long as exposure to light causes a difference in solubility in a developer or changes in adhesiveness at the interface with the upper silicone rubber layer. It can be used even if

Compounds or compositions constituting such a photosensitive layer include the following.

(A) Photopolymerizable photosensitive resin layer: (1) Monomer or oligomer having an olefinically unsaturated double bond group, (2) a polymeric compound having film-forming ability, used as necessary, and (3 ) A layer of a photopolymerizable composition comprising a photopolymerization initiator. The above components (1) to (3)
) in the photosensitive resin layer containing components (1) and [2) bonded together, i.e., having a photopolymerizable or photocrosslinkable and olefinic unsaturated double bond group in the side chain. A photosensitive resin layer containing a polymer compound having film-forming ability is also suitable for use in the present invention. In addition, in the compound in which components (1) and (2) are combined,
A photosensitive resin layer to which monomers or oligomers are added is more suitable. However, the present invention is not limited to these.

Such monomers or oligomers include monofunctional acrylates and methacrylates such as polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, and phenoxyethyl(meth)acrylate; polyprolene glycol di(meth)acrylate, and Methylolethane tri(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, hexanediol di(meth)acrylate,
Trimethylolpropane tri(acryloyloxypropyl) ether, tri(acryloyloxyethyl)
Isocyanurate, calcium (meth)acrylate, (
Sodium meth)acrylate, polyfunctional alcohol such as glycerin or trimethylolethane, which is converted into (meth)acrylate after adding ethylene oxide or propylene oxide, Japanese Patent Publication No. 48-41708, Japanese Patent Publication No. 50-6034 Urethane acrylates as described in JP-A No. 51-37193, polyester acrylates as described in JP-A-48-64183, JP-B No. 4943191, and JP-A-52-30490, epoxy Polyfunctional acrylates and methacrylates such as epoxy acrylates made by reacting resin with (meth)acrylic acid, U.S. Patent No. 4,540,649
Examples include N-methylolacrylamide derivatives described in Japanese Patent Publication No. Furthermore, Japan Adhesive Association Journal Vol.

20, Nα7. Those introduced as photocurable monomers and oligomers on pages 300 to 308 can also be used. These monomers and oligomers generally account for 70 to 1% by weight, preferably 50 to 1% by weight of the total photosensitive resin layer.
Contained at 3% by weight.

Component (2): Compound having film-forming ability Polymer compounds having such film-forming ability include methacrylic acid copolymer, acrylic acid copolymer, crotonic acid copolymer, maleic acid copolymer, Esterified maleic acid copolymer, acidic cellulose derivative, polyvinylpyrrolidone, polyethylene oxide, alcohol-soluble nylon, polyester, unsaturated polyester, polyurethane, polystyrene, epoxy resin, phenoxy resin, polyvinyl butyral, polyvinyl formal, polyvinyl chloride, polyvinyl Examples include alcohol, partially acetalized polyvinyl alcohol, water-soluble nylon, water-soluble urethane, gelatin, and water-soluble cellulose derivatives.

Polymer compounds in which components (1) and (2) are combined Examples of such polymer compounds include allyl (meth)acrylate/acrylate as described in JP-A-59-53836;
(meth)acrylic acid/other addition-polymerizable vinyl monomer copolymers as needed, and their alkali metal salts or amine salts; hydroxyethyl ((meth)acrylate/ <Meth)acrylic acid/alkyl (meth)acrylate copolymer and its alkali metal salt or amine salt reacted with (meth)acrylic acid chloride; JP-A-59-710
Pentaerythritol triacrylate added to a maleic anhydride copolymer by half-esterification as described in Publication No. 48, and its alkali metal salt or amine salt; monohydroxy added to a styrene/maleic anhydride copolymer Alkyl (meth)acrylates, polyethylene glycol mono (meth)acrylates, polypropylene glycol mono (meth)acrylates added by half-esterification, and their alkali metal salts and amine salts;
(Meth>acrylic acid copolymers and crotonic acid copolymers in which part of the carboxylic acid is reacted with glycidyl (meth)acrylate, and their alkali metal salts and amine salts; hydroxyalkyl (meth)acrylate copolymers, Polyvinyl formal, polyvinyl butyral reacted with maleic anhydride or itaconic anhydride, and their alkali metal salts and amine salts; hydroxyalkyl (meth)acrylate/(meth)acrylic acid copolymer with 2,4-tolylene diisocyanate /Hydroxyalkyl (meth)acrylate-1/i adducts and their alkali metal salts and amine salts; one of the <meth)acrylic acid copolymers described in JP-A No. 59-53836 (meth)vinyl acrylate/(meth)acrylic acid copolymer and its alkali metal salt or amine salt; (meth)oriru acrylate /sodium styrene sulfonate copolymer; (meth) vinyl acrylate/sodium styrene sulfonate copolymer,
(meth)allyl acrylate/acrylamide-l, 1
- Sodium dimethylethylene sulfonate copolymer, (
meth) Vinyl acrylate/acrylamide-1゜1-dimethylethylene sulfonate sodium copolymer, 2-allyloxyethyl methacrylate/methacrylic acid copolymer, 2-allyloxyethyl methacrylate/2-methacryloxyethyl hydrogen succinate Copolymers and the like can be mentioned.

This polymer compound generally contains 30-9% of the total photosensitive resin layer.
0% by weight, preferably 50-97% by weight.

Component (3): Photopolymerization initiator As such a photopolymerization initiator, U.S. Pat.
7,660; α- as disclosed in U.S. Pat. Nos. 2.367,661 and 2.367,670;
carbonyl compounds, acyloin ethers as disclosed in U.S. Pat. No. 2.448.828, alpha-hydrocarbon substituted aromatic acyloins as disclosed in U.S. Pat. No. 2.722.512; Compounds, polynuclear bovine non compounds disclosed in U.S. Pat. No. 3.046.127 and U.S. Pat. No. 2.951.758,
The triarylimidazole dimer/p-aminophenyl ketone combination disclosed in U.S. Pat. No. 549.367, the benzothiazole compounds disclosed in U.S. Pat.
Benzothiazole compounds/trihalomethyl-5-triazine compounds disclosed in US Pat. No. 239.850 and acridine and phenazine compounds disclosed in US Pat. No. 3.751.259, US Pat. Oxadiazole compounds disclosed in U.S. Pat. No. 3,954.475, JP-A-53-133428, U.S. Pat.
No. 23, JP-A-60-105667, JP-A-62-5
8241, trihalomethyl-5-triazine compounds having a chromophoric group disclosed in Japanese Patent Application No. 61-227489, JP-A-59-197401, JP-A-6
Examples include benzophenone group-containing peroxyester compounds disclosed in Japanese Patent No. 0-76503.

The amount of these photopolymerization initiators added is 0.1 to 20% by weight, preferably 1 to 10% by weight, based on the total photosensitive resin layer.

In addition to the other components mentioned above, a small amount of photocurable diazo resin may be added to the photosensitive resin layer in order to improve the adhesion with the primer layer. Such diazo resins include U.S. Pat. No. 3.867,147 and U.S. Pat. No. 2.632.70.
Examples include those described in No. 3 specification, but in particular aromatic diazonium salts and active carbonyl-containing compounds (e.g.
Diazo resins typified by condensates with formaldehyde (formaldehyde) are useful. Preferred diazo resins include, for example, fluorophosphates, tetrafluoroborates, and phosphates of condensates of p-diazodiphenylamine and formaldehyde or acetaldehyde. Also, sulfonates of condensates of p-diazodiphenylamine and formaldehyde (e.g., [)-toluenesulfonate, 2
-Methoxy-4-hydroxy-5-benzoylbenzenesulfone! Salts, etc.), phosphinates, organic carboxylates, etc. are also preferred.

The preferred amount of the diazo resin added is 0.1 to 5% by weight based on the total photosensitive resin layer. Furthermore, it is preferable to add a thermal polymerization inhibitor to the photosensitive resin layer, such as pydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4. 4'-thiobis(3-methyl-
6-t-butylphenol), 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2-mercaptobenzimidazole, and the like are useful. Further, depending on the case, a dye or pigment may be added for the purpose of coloring the photosensitive resin layer, or a pH indicator or a leuco dye may be added as a print-out agent. Depending on the purpose, a small amount of polydimethylsiloxane, methylstyrene-modified polydimethylsiloxane, olefin-modified polydimethylsiloxane, polyether-modified polydimethylsiloxane,
A silicone compound such as a silane coupling agent, silicone diacrylate, or silicone dimethacrylate may be added. Furthermore, a fluorine-based surfactant or a fluorine-based surface alignment agent may be added to improve coating suitability.

The amount of these additives added is usually 10% by weight or less based on the total photosensitive resin layer. Furthermore, in some cases, to strengthen the adhesion with the silicone rubber layer, silica powder or hydrophobic silica powder whose surface has been treated with a (meth)acryloyl group or allyl group-containing silane coupling agent is applied to the entire photosensitive resin layer. It may be added in an amount of 50% by weight or less.

(B) Photodimerization type photosensitive layer: The following groups in the main chain or side chain of the polymer: or (R has 1 to 1 carbon atoms 0 alkyl group) (R,, R2 each represents an alkyl group, R.

and 2 may be taken together to form a 5- or 6-membered ring) or (R represents an alkyl group having 1 to 10 carbon atoms).

For example, polymers whose main component is a photosensitive polymer such as stellates, polyamides, and polycarbonates with a photosensitive group in the main chain or side chain of the polymer, for example, U.S. Pat. .707.373 and 3.453.237); from (2-properidene) malonic acid compounds such as cinnamylidene malonic acid and difunctional glycols; derived photosensitive polyesters (e.g., U.S. Pat. No. 2.956.878 and U.S. Pat.
．． 173.737); cinnamate esters of hydroxyl-containing polymers such as polyvinyl alcohol, starch, cellulose, and the like (e.g., U.S. Pat. 2.690.966
No. 2.752.372, No. 2, 732.30
Photosensitive polymers as described in the specifications of No. 1, etc.)
, and also JP-A-58-25302 and JP-A-59-17550.
The polymers described in the above publication are included.

(C) Composed of a photocurable diazo resin or azide resin, a photosensitizer if necessary, and some filler additives: As the photocurable diazo resin, Vara diazo diphenylamine, Vara diazo monoethylaniline , a zinc chloride double salt of a condensate of a diazo amine and formaldehyde, such as diazobenzylethylaniline.

This photosensitive resin layer is essentially different from the photosensitive resin layer mentioned in (A) in that it does not contain a compound having a photopolymerizable unsaturated double bond group.

Examples of photocurable azide resins include acidophthalate ester of polyvinyl alcohol, azidobenzoate ester, ester of styrene-maleic anhydride copolymer, and aromatic azide alcohol such as β-(4-azidophenol)ethanol. can be given.

As the photosensitizer, filler, and additives, those listed in the example (A) can be used.

The silicone rubber layer preferably used in the present invention is a linear or partially crosslinked polydiorganosiloxane and has the following repeating units.

Here, R represents an alkyl group, an aryl group, an alkenyl group, or a combination of these monovalent groups, and these are halogen atoms, amine groups, hydroxy groups, alkoxy groups, aryloxy groups, (meth)acryloxy groups, thiol It may have a functional group such as a group. In addition, silicone rubber may contain fine powders of inorganic substances such as silica, calcium carbonate, and titanium oxide, adhesives and photopolymerization with the above-mentioned silane coupling agents, titanate coupling agents, and aluminum coupling agents. An initiator may also be added.

As a raw material for the above-mentioned high molecular weight polymer (silicone rubber) whose main skeleton is polysiloxane, polysiloxane having a molecular weight of several thousand to several hundred thousand and having a functional group at the end is used.
This is crosslinked and cured in the following manner to obtain a silicone rubber layer. Specifically, a silane crosslinking agent represented by the following general formula is mixed into the polysiloxane having a hydroxyl group at both ends or only at one end, and if necessary, an organometallic compound such as an organotin compound is added. A catalyst such as an inorganic acid or an amine is added, and the polysiloxane and the silane crosslinking agent are heated or condensed and cured at room temperature.

R, SiX, -n Here, n is an integer of 1 to 3, R is a substituent group similar to R shown above, and X represents a group such as ichi-Ko, -〇R2, -〇Ac, or a group. Here, R2 and R3 have the same meaning as R described above, and R2 and R3 may be the same or different. Moreover, Ac represents an acetyl group.

Other organopolysiloxanes with hydroxyl groups at the ends,
The hydrogen polysiloxane crosslinking agent and, if necessary, the above-mentioned silane crosslinking agent are condensed and cured.

In addition, an addition-type silicone rubber layer crosslinked by an addition reaction between a 3 S i H group and a -CH=CH- group is also useful. The addition-type silicone rubber layer is relatively unaffected by humidity during curing, and can be crosslinked at high speed.
It has the advantage that certain physical properties can be easily obtained. In the case of a condensation type silicone rubber layer, if carboxylic acid is present in the photosensitive resin layer, curing failure may occur depending on the crosslinking agent used, whereas with an addition type silicone rubber layer, curing is sufficient even in the presence of carboxylic acid. happens. Since carboxylic acid can be present in the photosensitive resin layer in this way, it is possible to easily design a photosensitive printing plate that can be developed with a developer mainly containing water or alkaline water. The addition-type silicone rubber layer used here is obtained by the reaction of a polyvalent hydrogen organopolysiloxane and a polysiloxane compound having two or more -CH=CH- bonds in one molecule, and preferably contains the following components: : (1) 100 parts by weight of an organopolysiloxane having at least two alkenyl groups (more preferably vinyl groups) directly bonded to silicon atoms in one molecule (2) At least two S i H bonds in one molecule
Onoganohydrodiene polysiloxane 0.1
~1000 parts by weight (3) Addition catalyst A composition made of 0.00001 to 10 parts by weight is cured and crosslinked. Ingredient (1)
The alkenyl group may be located either at the end or in the middle of the molecular chain, and organic groups other than the alkenyl group include substituted or unsubstituted alkyl groups and aryl groups. Ingredient (1)
Optionally, it may have a trace amount of hydroxyl group. Ingredient (2)
reacts with component (1) to form a silicone rubber layer, but also plays the role of imparting adhesiveness to the photosensitive resin layer.

The hydrogen group in component (2) may be located either at the end or in the middle of the molecular chain, and the organic groups other than hydrogen are selected from the same ones as in component (1). In order to improve ink repellency, it is preferable that 60% or more of the organic groups in component (1) and component (2) be methyl groups. Ingredients (1) and (2)
The molecular structure of may be linear, cyclic, or branched, and the molecular weight of at least one of them is 1. It is preferable from the viewpoint of rubber physical properties that it exceeds o o o, and furthermore, component (1)
The molecular weight of preferably exceeds 1.000.

Examples of component (1) include α,ω-divinylpolydimethylsiloxane, (methylvinylsiloxane)(dimethylsiloxane) copolymer having methyl groups at both ends, and component (2), which has methyl groups at both ends. Examples include polydimethylsiloxane, α,ω-dimethylpolymethylhydrodienesiloxane, (methylhydrodienesiloxane)(dimethylsiloxane) copolymer having methyl groups at both ends, and cyclic polymethylhydrodienesiloxane.

The addition catalyst of component (3) is arbitrarily selected from known ones, but platinum-based compounds are particularly preferred, and examples include simple platinum, platinum chloride, chloroplatinic acid, and olefin-coordinated platinum. To control the curing rate of these compositions, organopolysiloxanes containing vinyl groups such as tetracyclo(methylvinyl)siloxane, alcohols containing carbon-carbon triple bonds, acetone, methyl ethyl ketone, methanol, ethanol, propylene glycol monomethyl It is also possible to add crosslinking inhibitors such as ethers.

In these compositions, an addition reaction occurs and curing begins when the three components are mixed, but the curing rate is characterized by rapidly increasing as the reaction temperature increases. Therefore, in order to lengthen the pot life of the composition until it turns into a rubber and shorten the curing time on the photosensitive resin layer, the curing conditions for the composition are set at a temperature within a range that does not change the characteristics of the substrate and the photosensitive resin layer. From the viewpoint of stability of adhesive force with the photosensitive resin layer, it is preferable to maintain the photosensitive resin at a high temperature until completely cured.

In addition to these compositions, known adhesion promoters such as alkenyltrialkoxysilanes may be added, or organopolysiloxanes containing hydroxyl groups, silanes containing hydrolyzable functional groups (or It is also optional to add siloxane), and it is also optional to add a known filler such as silica for the purpose of improving the rubber strength.

The silicone rubber layer in the present invention serves as a printing ink repellent layer, and if the thickness is small, the ink repellency decreases,
If there are problems such as easy scratches and the thickness is large,
The thickness should be from 0.5 to
5 μm is suitable.

In the photosensitive lithographic printing plate that does not require dampening water as described herein, it is optional to further coat various silicone rubber layers on the silicone rubber layer, and the adhesion between the photosensitive resin layer and the silicone rubber layer is also optional. It is also optional to provide an adhesive layer between the photosensitive resin layer and the silicone rubber layer for the purpose of increasing the strength or preventing poisoning of the catalyst in the silicone rubber composition. For surface protection of silicone rubber layer,
On the silicone rubber layer, a transparent film such as polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyethylene terephthalate, cellophane, etc. may be laminated or a polymer coating may be applied.

The photosensitive planographic printing plate that does not require dampening water according to the present invention is exposed to light through the original image, and then developed using a developer that can dissolve or llR11 partially or completely the photosensitive resin layer in the image area, or that can swell the silicone rubber layer. Developed with liquid. In this case, there are cases in which the photosensitive resin layer in the image area and the silicone rubber layer thereon are removed, and cases in which only the silicone rubber layer in the image area is removed, and this can be controlled by the strength of the developer. .

As the developer used in the present invention, those known as developers for photosensitive lithographic printing plates that do not require dampening water can be used. For example, aliphatic hydrocarbons [hexane, heptane,
'Isopar E, H, G' (trade name of aliphatic hydrocarbons manufactured by Esso Chemical @)] or gasoline, kerosene, etc., aromatic hydrocarbons (toluene, xylene, etc.), or halogenated hydrocarbons (triclene, etc.) Preferably, the following polar solvents are added to the solvent, or the polar solvent itself is used.

Alcohols (methanol, ethanol, propatool, benzyl alcohol, ethylene glycol monophenyl ether, 2-methoxyethanol, 2-ethoxyethanol, carpitol monoethyl ether, carpitol monomethyl ether, triethylene glycol monomethyl ether, propylene glycol monomethyl ether) , propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, polyethylene glycol monomethyl ether, propylene glycol, polypropylene glycol, triethylene glycol, tetraethylene glycol) Ketones (acetone, methyl ethyl ketone) Esters (ethyl acetate, methyl lactate, ethyl lactate) , butyl lactate,
propylene glycol monomethyl ether acetate,
Calpitol acetate, dimethyl phthalate, diethyl phthalate) Others (triethyl phosphate, tricresidyl phosphate) Adding water to the above organic solvent developer, or solubilizing the above organic solvent in water using a surfactant, etc. Furthermore, alkaline agents such as sodium carbonate, monoethanolamine, jetanolamine, triethanolamine, sodium silicate, potassium silicate, sodium hydroxide, potassium hydroxide, sodium borate, etc. are added thereto. Or, in some cases, simply tap water or alkaline water can be used as a developer.

Furthermore, dyes such as crystal violet and astrazone red can be added to the developer to dye the image area simultaneously with development.

Development can be carried out by a known method, for example, by rubbing the printing plate with a developing pad containing a developer as described above, or by pouring the developer onto the printing plate and then rubbing it under water with a developing brush. As a result, the silicone rubber layer and photosensitive resin layer in the image area are removed, exposing the surface of the substrate or the brimer layer, which becomes the ink receiving area, or only the silicone rubber layer in the image area is removed and the photosensitive layer is exposed. is exposed and that part becomes the ink receiving area.

〔Example〕

The present invention will be further explained below with reference to Examples, but the present invention is not limited to these Examples.

In addition, although the results of the forced scratch test are shown in the text,
The test method was to rub the non-image area of the printing plate with an aluminum plate, print using a Heidelberg GTO printing machine with the dampening water supply device removed and Toyo Aquares Five ink made by Toyo Ink, and measure the amount of scratches covered with ink. This was determined by.

Example 1.2 The following primer layer composition (a) was applied to a smooth aluminum plate degreased in a conventional manner to a dry weight of 10.0 g/m', and then heated at 120°C for 3 minutes. Heat and dry harden.

A solution consisting of was heated to 70°C, and the following casein powder was added and dissolved while stirring.

Next, the following components were blended into this casein aqueous solution to prepare a primer layer composition (a).

Next, on the primer layer, 3.0 g of photosensitive resin layer compositions (A) and (B) consisting of the following components were applied in dry weight.
/m' and dried at 100°C for 1 minute.

These are referred to as Examples 1 and 2, respectively.

Composition for photosensitive resin layer (A) Composition for photosensitive resin layer (B) 2.0% dry weight of the following composition for silicone rubber layer was applied on these photosensitive resin layers (A) and (B). It was coated at a concentration of 0 g/m' and dried at 140°C for 2 minutes to obtain a silicone rubber layer.

A single-sided matted polypropylene film having a thickness of 9 μm was laminated on the surface of the silicone rubber layer obtained as described above to obtain a waterless lithographic original plate.

A positive film was layered on this printing original plate, and the film was vacuum-adhered to the original printing plate.
-PL[l5FLIP-TOP PLATB! , I.A.K.
After 30 counts of exposure with MiR, the laminate film was peeled off and immersed for 1 minute in a developer consisting of 12 parts by weight of benzyl alcohol, 5 parts by weight of sodium isopropylnaphthalene sulfonate, 1 part by weight of triethanolamine and 82 parts by weight of water. When rubbed with a developing pad, the photosensitive resin layer and silicone rubber layer in the unexposed areas were removed.

As a result, a waterless lithographic printing plate was obtained that faithfully reproduced the image of the positive film over the entire surface of the printing plate.

Example 3 On the same primer layer as in Examples 1 and 2, 4.0 g of photosensitive resin layer composition (C) consisting of the following components was applied in dry weight.
/m' and dried at 100°C for 1 minute.

Composition for Photosensitive Resin Layer (C) 0 parts by weight of dimethylformamide A silicone rubber layer similar to Examples 1 and 2 was provided on this photosensitive resin layer to prepare Example 3.

The printing original plate of Example 3 was exposed to light in the same manner as in Example 1.2, and after peeling off the laminate film, it was immersed in polypropylene glycol (molecular weight 200) at 40° C. for 1 minute. After immersion, the processing liquid on the plate surface was removed with a rubber squeegee, and the silicone rubber layer in the unexposed areas was removed by rubbing it with a developing pad while showering with water. As a result, a waterless Heiichizaka printing plate that faithfully reproduced the image of the positive film was obtained.

Examples 4 to 6 Primer layer compositions (b) to (d) below were applied to a smooth aluminum plate degreased in the same manner as in Example 1 to a dry weight of 10 g/m'', and heated at 120°C for 3 minutes. It was heated to dry and harden.

Primer layer composition (b) Ingredients below: After mixing and sufficiently swelling, the mixture was heated and dissolved at 40°C.

Next, the following components were blended into this gelatin aqueous solution to prepare a primer layer composition (b).

Brimer footwear composition (d) The photosensitive resin layer composition (A>) was applied to the primer layers (b) to (d) prepared in this way at a dry weight of 3°O.
g/m' and dried at 100°C for 1 minute. Next, the silicone rubber footwear composition was applied onto this photosensitive resin layer at a dry weight of 2.0 g/m'' and dried at 140°C for 2 minutes to obtain a silicone rubber layer. A waterless lithographic printing plate was obtained by carrying out the same treatment as in Example (2).

Comparative Example 1 As a comparative example, a waterless lithographic printing original plate was prepared in the same manner as in Example 1, except that the polyether type polyurethane latex was removed from the primer layer composition (a) and the solid content was replaced with lactic acid casein. A waterless lithographic printing plate of Comparative Example 1 was obtained by the same operation as in Example 1.

Comparative Example 2 The lactic acid casein was removed from the primer layer composition (A) and the solid content was converted into polyether type polyurethane latex (
A waterless lithographic printing plate was prepared in the same manner as in Example 1, except that the waterless lithographic printing plate was replaced with Bondic 1050), and a waterless lithographic printing plate of Comparative Example 2 was obtained in exactly the same manner as in Example 1.

Table 1 summarizes the forced scratch printing results of all printing plates obtained in Examples 1 to 6 and Comparative Examples 1 and 2.

〔Effect of the invention〕

The waterless lithographic printing original plate according to the present invention has excellent scratch resistance and can provide printed matter that faithfully reproduces the image of a positive film.

Claims (1)

[Scope of Claims] A lithographic printing original plate that does not require dampening water, in which a primer layer, a photosensitive resin layer, and a silicone rubber layer are sequentially provided on a support,
A dampening water-less lithographic printing characterized in that the primer layer contains the following components: (a) at least one natural protein selected from casein, gelatin, soybean protein, and albumin, and (b) a urethane elastomer. Original plate.