JPS63304244A - Photopolymerizable composition - Google Patents

Abstract

PURPOSE:To improve the wear and chemical resistances of a photopolymerizable compsn. without deteriorating other performance when the compsn. is used for a photosensitive planographic printing plate, by incorporating a copolymer having a specified structure. CONSTITUTION:A copolymer contg. at least 1-20mol.% structural units represented by the formula (where R is H or methyl and -X- is -NH- or -O-) and contg. preferably methacrylic acid or methyl methacrylate as other copolymerizable component is used as a binder. A compd. having >=100 deg.C b.p. under ordinary pressure and contg. two or more polymerizable terminal ethylene groups and a photopolymn. initiator which is activated by active rays of light are added to the binder to obtain a photopolymerizable compsn. The resistance of the compsn. to wear and chemicals such as a plate cleaner used after printing can be improved by using the copolymer as the binder.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a photopolymerizable composition that can be used in photosensitive lithographic printing plates, photoresists, and the like.

More specifically, when used in a photosensitive lithographic printing plate, K and b are excellent in developability with an alkaline aqueous solution containing a small amount of organic solvent, and have excellent chemical resistance to chemicals such as plate cleaners used during printing. This invention relates to a photopolymerizable composition with excellent dye removal and abrasion resistance.

[Prior art and problems to be solved by the invention] Conventionally, the fact that photosensitive lithographic printing plates can be developed with an aqueous alkaline solution or an aqueous alkaline solution containing a small amount of organic solvent has led to reductions in plate-making costs, low pollution and This was desirable in terms of work process management.

As a product that can be selected from the above alkaline water bath solution, a photocurable resin for lithographic printing plates is produced by using a copolymer of methacrylic acid and methyl methacrylate as a binder polymer, and adding a crosslinking agent and a photopolymerization promoter to this binder polymer. For example, the method of
♂9! No., Tokko Sho Geta No. 4t4'93J-, and Tokko Sho 4t4-3 Core 74 are described in the publications such as No. However, although these conventional compositions can be developed with an alkaline aqueous solution or an alkaline aqueous solution containing a small amount of organic solvent, their chemical resistance, pigment loss, and abrasion resistance are not sufficient, and improvements have been desired. .

As a result of consideration, we found that the binder has at least the following general formula (1) % formula % (1) (wherein R is a water 1g atom or a methyl group, -X-
represents -NH- or -〇-. ) It is known that the desired purpose can be achieved by using a polymer containing / to -0 mol of the structural unit, preferably a copolymer containing methacrylic acid and methyl methacrylate as other copolymerization components. With these results, we have completed the present invention.

That is, the gist of the present invention is as follows: ←) The structural unit represented by the following general formula (1) is
Copolymer containing molti, ■ -OH, -0-curve (1) 0.0 ■ 4 for a' (In the formula, R is a hydrogen atom or a methyl group, -X- is -NH- or '-〇-.) (B) A compound with a boiling point under normal pressure of iooo°C or more and containing one or more polymerizable terminal ethylene groups, and (0) Contains a photopolymerization initiator activated by actinic rays. A photopolymerizable composition characterized by:

The present invention will be explained in detail below.

The copolymer used in the present invention contains 7 to 20 moles of the structural unit represented by the above general formula (1). If the content is too small, the chemical resistance, abrasion resistance, and dye removal properties will be reduced, and if the content is too large, the developability when used in a printing plate will be reduced. Examples of the monomer forming the m-acid unit represented by the general formula (1) include p-cyanophenyl (
Examples thereof include meth)acrylamide, 0-cyanophenyl(meth)acrylamide, p-cyanophenyl(meth)acrylate, and 0-cyanophenyl(meth)acrylate. These monomers can be used alone or in combination, but p-cyanophenyl (meth)acrylamide or 0-cyanophenyl (meth)acrylamide is preferred.

Although the units other than the formula (1) constituting the copolymer (←) are not limited to %, it is preferable to use methacrylic acid and methacrylic acid alkyl ester as monomers and to have a structural unit formed from these.

In this case, monomers that provide the structural units formed by methacrylic acid alkyl esters include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, pentyl methacrylate, and 4-ethylhexyl methacrylate. Examples include using one or more of them in combination, and methyl methacrylate, ethyl methacrylate, and more preferably methyl methacrylate are suitable.

Furthermore, it is also possible to copolymerize other copolymerizable monomers depending on the required use. Such copolymerizable monomers include acrylic acid esters such as methyl acrylate, ethyl acrylate, tetravir acrylate, butyl acrylate, and hexyl acrylate, vinyl chloride, acrylonitrile, styrene, and vinyl such as vinyl acetate. Compounds can be mentioned. In particular, these monomers are expressed in amounts charged relative to the monomer forming the unit of general formula (1), methacrylic acid, and methacrylic acid alkyl ester (the same applies hereinafter). It is desirable that it be less than θ molti, preferably less than y0 molti.

The copolymer (A) of the present invention can be synthesized from these desired monomers by conventional radical polymerization, and methods such as general Km turbid polymerization and solution polymerization can be used.

Thus, the monomer ratio in the obtained copolymer is approximately proportional to the molar ratio of the monomers charged.

When the above-mentioned methacrylic acid and methacrylic acid alkyl ester are used as copolymer components, the monomers forming the general formula (1) are mixed with / to -0 mol, methacrylic acid 3 to 4 tO mol, and methacrylic acid alkyl ester 30 to 4 tO mol. ? It is preferable to carry out the reaction by charging θmolti. In particular, the copolymer (c)) is made of monomers forming the unit of general formula (1), methacrylic acid, methyl methacrylate, and ethyl acrylate. Preferably, the copolymer is
Furthermore, a copolymer containing acrylonitrile as a monomer is preferred.

The usage ratio of these monomers is such that the monomers forming the structural unit of general formula (1) are /~20 molt, preferably /~/θ
molty, methacrylic acid is /-j-0 molty, preferably j-4tO molty, particularly preferably 3 to 30 molty, ethyl acrylate is /-410 molty, preferably 3 to 3
0 mole, especially preferably! 〜-〇molti, acrylonitrile cuff ~da 0 molti, preferably 3 to 30 molti,
Especially preferably! A copolymer having a composition selected from the range of ~-Omolti and the remainder being methyl methacrylate is preferred.

When the composition of the present invention is used in a lithographic printing plate, if the amount of methacrylic acid used is small, the solubility in the developer tends to be too low, and the plate stains due to ink adhering to unexposed areas after development. If the amount is too high, the solubility in the developer becomes too high, making it easy for the image to disappear when the methacrylic acid alkyl ester is used, and the ink receptivity is improved when an alkyl methacrylate ester is used.

The preferred weight average molecular weight of the above-mentioned copolymer GA) of the present invention is 10,00θ~zoo, θoo, and furthermore koθ, ooθ~
4too, ooo, particularly preferably 4to, o o
o~λθo, o o o. If the weight average molecular weight is small, the solubility in the developer will be too high and the image will easily disappear during development.If the weight average molecular weight is large, the solubility in the developer will decrease and the unexposed areas will dissolve during development. It becomes difficult.

The boiling point under normal pressure used in the present invention is 100°C or higher, and 1
Compound Φ containing one or more terminal ethylene groups that can be combined
), any known virtuous material can be used. for example,
Unsaturated carboxylic acids, esters of unsaturated carboxylic acids and aliphatic polyhydroxy compounds, esters of unsaturated carboxylic acids and aromatic polyhydroxy compounds, unsaturated carboxylic acids and polyhydric carboxylic acids, and the aforementioned aliphatic polyhydroxy compounds, esters obtained by esterification reaction with polyhydric hydroxy compounds such as aromatic polyhydroxy compounds, etc. Specifically, examples include esters obtained by esterification reaction with polyhydric hydroxy compounds such as aromatic polyhydroxy compounds. (meth)acrylate, triethylene glycol di(meth)
acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol triacrylate,
Examples include hydroquinone di(meth)acrylate, pyrogallol triacrylate, 2,2'-bis(4t-acryloxy-jethoxyphenyl)propane, and the like.

Other K Ha, ethylene bis(meth)acrylamide,
Examples include (meth)acrylamides such as hexamethylenebis(meth)acrylamide, vinyl urethane compounds, and epoxy(meth)acrylates.

Furthermore, as the photopolymerization initiator←), conventionally known ones that can be activated by actinic rays can be used, such as hachenzoin, benzoin alkyl ether, benzophenone, anthraquinone, benzyl, Michler's ketone, a complex system of biimidazole and Michler's ketone, etc. Any of them can be suitably used. In addition, in order to effectively sensitize the visible light of an argon ion laser, for example, a composite system of biimidazole and a ruaminostyryl derivative in sial 1.2. ￥, 4-tris (trichloromethyl)
-i, 3. Complex system of t-triazine and cyanine dye derivative, λ, 4t, 4-) lis(trichloromethyl)
A composite system of -/, J, j-triazine and a thiavi IJ derivative is suitable.

The proportions of the components constituting the photopolymerizable composition of the present invention are usually 10 to 20% by weight, preferably 30 to 10% by weight for the copolymer (A), and 10 to 20% by weight for the copolymer (A), and 30 to 10% by weight for the addition type unsaturated compound. (
81 is 20 to 0% by weight, preferably 4to-tro
Weight/weight photopolymerization initiator (q is selected from the range of 0.1 to 1, preferably 0.6 to 30 weight).

In the photopolymerizable composition of the present invention, a 9-polymer having a polyfunctional ethylenically unsaturated group at the side chain or end can be mixed and used, if necessary. It is possible to improve the adhesion to the base material when the base material is used.

The copolymer having a polyfunctional ethylenically unsaturated group in its side chain or terminal is composed of a polymer having a carboxylic acid or carboxylic anhydride in its side chain or terminal and a polyfunctional ethylenically unsaturated compound having a hydroxyl group. It can be easily obtained by carrying out an ester reaction using a known method.

Examples of polymers having carboxylic a1 or carboxylic anhydride in the side chain or terminal include (meth)acrylic acid homopolymers, (meth)acrylic acid/(meth)acrylic acid ester copolymers, and methylene/(meth)acrylic acid ester copolymers. ) Acrylic acid copolymers, methylene/maleic anhydride copolymers, and the like.

For these copolymers, if the molecular weight is too large, the imageability will be poor, and if the molecular weight is too small, the sensitivity and strength of the photocured bond will decrease, so the average molecular weight of the copolymer is /
, θ00 to jO,000 is preferable, particularly 2,
000~/θ, 000A4 Tsuru-ichi de z11-beginning 7 Specific examples of the polyfunctional ethylenically unsaturated compound include pentaerythritol triacrylate, pentaerythritol trimethacrylate, pentaerythritol diacrylate, pentaerythritol dimethacrylate, Trimethylolethane diacrylate, trimethylolethane dimethacrylate, trimethylolpropane diacrylate, trimethylolpropane dimethacrylate, dimethylolmethanol diacrylate, dimethylolmethanol dimethacrylate, trimethylolmethane diacrylate, trimethylolmethane dimethacrylate, etc. can be mentioned.

The reaction method for these polymers and polyfunctional ethylenically unsaturated compounds is the generally known esterification reaction between carboxylic acid and alcohol. For example, ethers or aromatic hydrocarbons are used as the reaction solvent. A method of heating in the presence of a catalyst such as sulfuric acid or para-toluenesulfonic acid can be mentioned. Furthermore, for carboxylic acid anhydrides, esterification products with unsaturated compounds having hydroxyl groups can be easily obtained by simply heating them in a solvent such as ethers or aromatic hydrocarbons. In addition, for example,
Examples include a method in which a polymeric carboxylic acid is converted into a carboxylic acid chloride using thionyl chloride or the like, and then reacted with an unsaturated compound having a hydroxyl group under an alkali catalyst such as pyridine or triethanolamine. In addition, when carrying out these reactions, in order to suppress addition polymerization of polyfunctional ethylenically unsaturated compounds, it is better to have a reducing substance present as a polymerization inhibitor in the reaction system. Noihydroquinone is effective as such a compound.

As the ratio of the polyfunctional ethylenically unsaturated groups introduced into the side chains of the polymer increases, the sensitivity improves, but the developability with respect to alkaline aqueous solutions decreases. Therefore, although it varies depending on the f1 class of the polymer used or the developing solution used, 0.0% of the carboxyl group of the original polymer is
3 to θ, r equivalent, particularly preferably 0.70 to 0. r0
Suitably, an equivalent amount of polyfunctional ethylenically unsaturated compound is added to the side chain of the polymer.

The amount of the copolymer having the side chain or terminal ysK polyfunctional ethylenically unsaturated group to be added is based on the copolymer of the present invention). It is appropriate to mix about ~j00'lL children.

In the present invention, a polymeric organic acid can be used for the purpose of improving developability, if necessary.

The polymeric acid is water soluble and has a concentration of 100 II/l in water.
It is possible to dissolve more than 1F. Such high-molecular organic acids are usually monomer units having carboxyl [j0~
Those having 700 moles of SaW, for example, acrylic acid polymers and their polymers, methacrylic acid polymers and copolymers thereof, and carboxylic acid-modified novolac resins. Among these, acrylic acid polymers are particularly preferred.

The weight average molecular weight of the polymeric organic acid is /, 000 to 100.
000. Preferably j, 000 to 3o, oo.

It is best to choose from the range. The amount used is 0.1 to 71% by weight, preferably 7 to 70% by weight in the photopolymerizable composition of the present invention.

As another component, a lipophilic plasticizer can be used, if necessary, for the purpose of improving storage stability.

Examples of lipophilic plasticizers include phthalic acid diesters, aliphatic dibasic acid esters, phosphoric acid triesters, and glycol esters. Specific examples of phthalic acid diesters include dibutyl phthalate, di-n-octyl phthalate,
Specific examples of di(-monoethylhexyl) phthalate, dinonyl phthalate, dilauryl phthalate, butyllauryl phthalate, butylbenzyl phthalate, and aliphatic dibasic acid esters include di(,2-ethylhexyl) adipate, Specific examples of di(-monoethylhexyl) bacate and triester phosphate include tricresyl phosphate and tri(-monoethylhexyl) phosphate.
Specific examples of the glycol esters (2-ethylhexyl) and glycol esters include polyethyl glycol esters and the like. Particularly preferred are phthalic acid diesters. The preferred usage amount is 0. /~ttto wt%, especially o3~3
0 weight.

Furthermore, known colorants may be used in combination with other components of the photopolymerizable composition of the present invention.

As a coloring agent, for example, Victoria Vinia Blue BOH
, crystal violet, methyl violet, ethyl violet, rhodamine B, guiacryl brilliant red 4B-N, or pigments such as phthalocyanine blue or chromophthal red, and the amount used is 0.1 to 20% by weight. Preferably 0.1-7
A range of 0% by weight is preferable.

Further, it is desirable to add a small amount of a thermal polymerization inhibitor to prevent unnecessary thermal polymerization of addition polymerizable unsaturated compounds that can be polymerized during storage.

Thermal polymerization inhibitors useful in the present invention include alkylated phenols such as λ,t-di-tertiary-butyl-nomethylphenol and alkylated bisphenols such as λ1.2-
Methylene-bis(4t-methyl-6-tert-butylphenol), i, 3°! -trimethyl-co, 4t, -tris(3,!-di-tert-butyl-hydroxybenzyl)benzene, -(4t-hydroxy-31-t)
-tert-butylanilino) -a,t-bis-(n
~octylthio) −/, 3. Examples include z-triazine, polymerized trimethyldihydroquinone, and dilaurylthiocyclobionate. Furthermore, a coating aid or the like may be added to modify or adjust the physical properties. Even if such additives are added in an amount equal to or less than the weight ratio of DA to the total weight of the three components A and O, the photopolymerizable composition of the present invention having a composition of 0 or more can be used without a solvent. Form a photosensitive material or dissolve it in a suitable solvent to make a solution, apply this onto a support and dry it to form a photosensitive material.
Ail. Examples of solvents include methyl ethyl ketone,
Acetone, cyclohexanone, ethyl acetate, butyl acetate, amyl acetate, ethyl propionate, toluene, xylene, benzene, monochrome benzene, gastric loform, carbon tetrachloride, trichloroethylene, trichloroethane, dimethylformamide, methyl cellosolve, ethyl cellosolve, butyl cellosolve, Examples of alcohols include tetrahydrofuran, pentoxone, methanol, ethanol, gropanol, propylene glycol monoethyl ether, and propylene glycol monoethyl ether.

The above photopolymerizable composition of the present invention can be applied to a support such as a polymer film or a metal plate such as a polyethylene terephthalate film, a zinc plate for printing, an aluminum plate for printing, a silicon wafer, a chromium-deposited glass plate, etc. in a conventional manner. The coating can be applied by well-known coating methods such as dip coating, coating rod, spray coating, spray coating, and roll coating.

When used as a photosensitive lithographic printing plate, it is preferable to use one coated on a printing aluminum plate whose surface has been anodized, especially aluminum which has been anodized in a bath of phosphoric acid or a mixed acid bath of phosphoric acid and sulfuric acid. Since the plate has good adhesion to the photopolymerizable composition of the present invention, it is preferable to %b0. Exposure light sources that can be applied to the photopolymerizable composition of the present invention include a carbon arc, a high-pressure mercury lamp, a xenon lamp, and a metal halide. lamps, fluorescent lamps, tungsten lamps, argon ion lasers, helium cadmium lasers,
Krypton laser etc./? UV rays of On31 or higher,
General-purpose light sources including visible light can be suitably used.

The photopolymerizable composition of the present invention can form a corresponding image on a support by imagewise exposure using such a light source and then developing with an aqueous alkaline solution or an aqueous solution containing an organic solvent and an alkali. Can be done.

The alkaline aqueous solution has a pH of l~/3, preferably pH9
It consists of enough alkaline material at 11 degrees to give ~/-2. In addition, the water bath solution may further contain a buffer, a surfactant, a dye, or a pigment.

Suitable alkalis include inorganic alkaline agents such as sodium silicate, potassium silicate, sodium hydroxide, aqueous potassium, lithium hydroxide, trisodium phosphate, trisodium phosphate, sodium bicarbonate, and trimethylamine. , diethylamine, monoethanolamine,
Examples include organic amine compounds such as n-butylamine, monoethanolamine, jetanolamine, and triethanolamine, and these can be used alone or in combination. Examples of the surfactant include polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene alkyl esters,
Nonionic surfactants such as sorbitan alkyl esters and monoglyceride alkyl esters; anionic surfactants such as rubenzenesulfone salts in alcohol, alkylnaphthalenesulfone M salts, alkyl sulfates, alkyl sulfonates, and sulfosuccinate ester salts; alkyl Ampholytic surfactants such as betaines and amino #1s can be used, and it is appropriate to incorporate them in a range of 0.7 to -txt%.

Aqueous solutions containing organic solvents and alkalis are
~! O capacity arrogant, preferably 1~ko! It is appropriate to include a capacitor.

Examples of organic solvents include Inglobil alcohol,
Benzyl alcohol, ethyl cellosolve, butyl cellosolve, diacetone alcohol, etc. can be contained as necessary, and it is particularly preferable to select one from those that are miscible with water.

In addition, in the photopolymerizable composition of the present invention, in the case of a photopolymerizable photosensitive composition containing an addition polymerizable unsaturated compound, etc.
Further, known techniques for preventing adverse effects such as a decrease in sensitivity due to oxygen, such as providing a removable transmissive cover sheet on the photosensitive composition layer, or using waxy substances with low oxygen permeability, [Examples] ] Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited by these Examples unless the gist thereof is exceeded.

Reference example/ (Al, % +=Nium surface treatment/) Thickness 0
．． 24tIIM aluminum plate! After degreasing in an aqueous sodium hydroxide solution, the temperature was 30°C and the current density was changed to a 0.3% nitric acid aqueous solution. OA/, d, processing time 30
Electrolytic etching treatment was performed under conditions of seconds. Then,
A desmutting treatment was carried out using an aqueous sodium hydroxide solution, and then anodizing treatment was carried out in a sulfuric acid bath at a temperature of JO''C1 current density of /64 and a treatment time of 30 seconds.

Reference example 2 (Aluminum plate surface treatment) Thickness 0.14
After degreasing a 1M11 aluminum plate in a 1% aqueous sodium hydroxide solution, 0. ! In molar aqueous hydrochloric acid solution, temperature, 2IC1 current density! OA/1M, processing time λ! Electrolytic etching treatment was performed under conditions of seconds. Next, 1%
Desmut treatment was performed with an aqueous sodium hydroxide solution, and then in a 30% sulfuric acid bath at a temperature of 30°C and a current density of t<A.
Anodization treatment was performed under the conditions of /J and treatment time of 30 seconds.

Reference example 3 (Aluminum plate surface treatment 3) Sharpness 0.24
After degreasing the aluminum and ram plates of TU in a JQK sodium hydroxide aqueous solution, 4to.

Graining was carried out using a rotating knife brush in a suspension of Messier crystal Bamisu water. Next, li#11 was subjected to polar oxidation treatment in a 4tO @ phosphoric acid bath at a temperature of 4to°C, a current density of 4tA/dd, and a treatment time of 30 seconds.

Synthesis example / Methyl methacrylate (MMA) / Methacrylic & (MAA) / Acrylic acid (mA) / Acrylonitrile (MN) / P-cyanophenylmethacrylamide (OP-/) [nignia: /2: 10: molar ratio (raw material charging ratio)] In a reaction vessel equipped with a stirrer and equipped with a reflux condenser and a nitrogen inlet, methacrylic acid 47- as the reaction am, and MMA, MAA, and Oi as monomers.

KAko/y, AN j, J, OF-//,
G Jl, and azobisisobutyronitrile (from A to M) 0. Juri I was added and reacted at an external temperature of 70°C for 7 hours. Next, the 1 reaction solution was poured into water with stirring, and the precipitate was dried over F to obtain the desired copolymer. (
This was used in Example 7 described later. ) The molecular weight was determined to be a weight average molecular weight of 10,000 using gel permeability chromatography.

In the same manner as above, the monomer composition of the preparation and the N
By appropriately changing the amount of , copolymers having the composition ratios shown in Table 1 were obtained.

Synthesis Example, 2 Synthesis of MCt Binder Styrene/Anhydrous! Leic acid copolymer (trivalent chemical styrite OM-co L1
Molecular weight approximately z, ooo) r, or # (o, o4t4t
), pentaerythritol triacrylate, / dag
(o, oλ moles), hydroquinone 20 cape was dissolved in dioxane totiltc, heated and stirred at 100"C for a long time, dropped into a large amount of water to precipitate, dried in vacuum, and obtained a carboxylic acid half ester polymer. (monofunctional resin) was synthesized.

Examples / ~ 2 and Comparative Examples / ~ Table / 1C Copolymers and trimethylolpropane triacrylate (Osaka Organic Chemical Industry Co., Ltd. TM) with various composition ratios shown
Dissolve 0 part of Pj in 1100 parts of ethylcetate,
To this, cordipenzoylmethylene-N-methyl-β-
Naphthothiazoline part λ, a, t-) lis(trichloromethytree/, JJ-) lyazine part, 1 part di(λ-ethylhexyl) phthalate, 0. ! , and 7 parts of Victoria Piao Blue BOH (Odougaya Chemical Industry Co., Ltd.) were added and dissolved to obtain a photosensitive solution. This photosensitive solution was applied to an aluminum plate that had been subjected to any of the seven treatments listed in Reference Example/~3. - was applied to give a dry layer thickness of 7-. Further, a polyvinyl alcohol aqueous solution was applied to the surface of this photosensitive layer to provide a protective layer having a dry film thickness of -Q/- to prepare a photosensitive lithographic printing plate. A negative star transmission film was vacuum-adhered to the surface of the resulting photosensitive lithographic printing plate, and J
kW high pressure mercury lamp (Kushio Unipulse UMli-3
000) from a light source distance of 7m! After second image exposure,
Negative PB plate developer BDN-2 manufactured by Konishiroku Photo Industry ■
Develop by rubbing the surface of the lithographic printing plate with an applicator using a cotton pad for 7 minutes with a 70 times diluted solution of / (negative development), or use developer solution for positive fJP 8 plate 5DR-/ manufactured by Konishiroku Photo Industry ■. The 10-fold diluted solution was developed by rubbing the surface of the lithographic printing plate with an applicator using a line pad for 7 minutes (positive development).

Using the obtained photosensitive lithographic printing plate, sensitivity, abrasion resistance, ink receptivity and chemical resistance were evaluated by the following methods, and the results are shown in Table 1.

(1) Sensitivity Sensitivity is expressed by the highest number of solid steps (the number of remaining photosensitive layers) K on a step tablet (step tablet image to be imaged), and the higher the number of peta steps, the higher the sensitivity.

(2) Using a printing plate obtained by vacuum-adhering an abrasion-resistant flat screen film, exposing it to light, and developing it, apply a load of 100 I, and apply Kodak's polymethic cleaner using an applicator to the printing plate. After rubbing 300 times, the deterioration of the image area was visually observed and evaluated using the following // point evaluation method.

/θ...--Extremely good.

!・・・・・・-The FiIJ main part has deteriorated considerably and small dots are flying.

O...-m- Using the printing plate obtained by filling in the disappearing image area, M: Sakura Great Gum Liquid (8GQ-J), B: Saxi Plate Gum Liquid (
Japan GW-Co) or C: After applying Fuji Plate gum solution (GU) and drying it, rub it lightly with a cellulose sponge 3 times and observe with a sac, and check the following! Each of A, B, and C was evaluated using the point evaluation method.

! ......-Extremely good. The ink is completely deposited on the image area.

3...--The ink is about the size of the image section! Only Qchi has been fleshed out.

／・・・・－・・The ink is almost not inked on Ao (
4) Using a printing plate obtained by developing a chemical-resistant transparent film without light in the SB state, immerse it in A Polymetic cleaner manufactured by Nikodak for Q minutes B: 3 in Lufit manufactured by Toka Shiki Co., Ltd. Partial immersion C: Dainichiseika Kaisha Ultra Plate Cleaner//θ
Minute immersion D: Development ink SP manufactured by Konishiroku Photo Industry Co., Ltd.

The deterioration state of the image area after being immersed in -/ for 60 minutes was visually observed. Each of the treatments A to D was evaluated using a point evaluation method.

! ......-Extremely good.

3...The rfMs section has deteriorated considerably and small dots are missing.

/・・・・・・-Image part disappears.

Monomer ap-2,0F-J in the table/herein.

op-a represents 0-cyanophenyl methacrylamide, p-cyanophenyl acrylamide, and p-cyanophenyl methacrylate, respectively.

In addition, comparative example/
In both cases, color loss occurred in the chemical resistance test.

〔Effect of the invention〕

As is clear from the examples, the photopolymerizable composition of the present invention is
By containing a copolymer with a specific structure, it is possible to improve the abrasion resistance and chemical resistance of photosensitive lithographic printing halftone plates without degrading other properties, making it extremely useful industrially. .

Sender: Santan Kasei Kogyo Co., Ltd. Representative Patent Attorney Hase - Others/names

Claims (4)

[Claims] (1) (A) A copolymer containing 1 to 20 mol% of the structural unit represented by the following general formula (I), ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・・・・
・(I) (In the formula, R is a hydrogen atom or a methyl group, and -X- represents -NH- or -O-.) (B) A polymerizable terminal with a boiling point of 100°C or higher under normal pressure A photopolymerizable composition comprising: a compound containing two or more ethylene groups; and (C) a photopolymerization initiator activated by actinic rays. (2) Claims characterized in that the monomer forming the structural unit represented by general formula (I) is p-cyanophenyl (meth)acrylamide or o-cyanophenyl (meth)acrylamide. The photopolymerizable composition described in (1). (3) Claims (1) or (2) characterized in that the copolymer (A) is a copolymer further containing a structural unit formed from methacrylic acid and methyl methacrylate. The photopolymerizable composition described in . (4) The weight average molecular weight of copolymer (A) is 10,000
500,000, the photopolymerizable composition according to any one of claims (1) to (3).