JPH08211596A - Photosensitive resin composition for printing plate and original plate for printing plate - Google Patents

Abstract

PURPOSE: To ensure superior flexographic ink resistance and flexibility by incorporating an ethylenically unsatd. compd., polyurethane having carboxyl groups, a gelling agent and a photopolymn. initiator. CONSTITUTION: This photosensitive resin compsn. contains an ethylenically unsatd. compd., polyurethane having carboxyl groups, a gelling agent and a photopolymn. initiator. The gelling agent has such characteristics as to make this compsn. gel, 12-hydroxystearic acid or benzylidene sorbitol is preferably used as the gelling agent and plural kinds of compds. may be used in combination. The polyurethane is used by 1-100 pts.wt. per 100 pts.wt. of the ethylenically unsatd. compd., the gelling agent is used by 0.1-20 pts.wt. and the photopolymn. initiator is used by 0.01-10 pts.wt.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive resin composition for a printing plate, and more particularly to a photosensitive resin composition for a printing plate and a water-developable printing plate having improved printing durability and flexibility. It relates to the original plate.

[0002]

2. Description of the Related Art A photosensitive resin composition in which an elastomer such as chlorinated rubber, styrene-butadiene block copolymer and polyurethane is used as a carrier resin component and an ethylenically unsaturated compound and a photopolymerization initiator are added to Utilizing the characteristics, it is useful as a flexographic printing plate material, for example, US Pat. Nos. 2,948,611 and 3,024.
No. 180, Japanese Patent Publication No. 51-43374, etc.
Many suggestions have been made.

Since such a photosensitive resin plate material requires a halogenated hydrocarbon as a developing solution, development of a photosensitive resin flexographic printing plate material which can be developed with water is desired. For example, US Pat. No. 023,973, No. 4,17
7,074, 4,247,624, 4,27
No. 2,608, No. 4,275,142, No. 4,41
No. 5,649, No. 4,431,723, No. 4,44
No. 6,220, No. 4,464,456, No. 4,51
Nos. 7,279, 4,689,298 and the like propose a photosensitive resin composition for providing a water-developable photosensitive resin flexographic printing plate material.

However, it is difficult to achieve both water developability, compatibility with water-based ink, which is the main ink for flexographic printing, and printing resistance, and it has not yet been practically satisfactory. For the purpose of solving the above problems, a photosensitive resin plate material that can be developed with water and has printing resistance to an ink containing a polar solvent such as water / alcohol is under study, and mainly liquid components. It is known that a desired photosensitive resin plate material can be obtained by gelling and solidifying a large amount of a photocurable component consisting of a small amount of a specific resin component, and further using a specific component known as an organic solvent gelling agent. (For example, JP-A-63-278053 and JP-A-63-287845). However, it is still not completely satisfactory in terms of water developability and flexographic printing resistance, and further improvement has been desired.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a photosensitive resin composition for a printing plate and a printing plate precursor which are excellent in flexo ink resistance and flexibility by improving the conventionally proposed technique. It is in.

[0006]

Means for Solving the Problems The present invention, which achieves the above objects, comprises (A) an ethylenically unsaturated compound, (B) a carboxyl group-containing polyurethane, (C) a gelling agent, and (D) a photopolymerization initiator. It is characterized by a photosensitive resin composition for a printing plate and a printing plate precursor comprising a sheet of this composition.

The present inventors have found that a photosensitive resin composition obtained by solidifying a large amount of an ethylenically unsaturated compound with a specific resin and a specific gelling agent has excellent water developability and is suitable for flexographic inks. It has been found that the present invention provides a solid flexographic printing plate material that is suitable and flexible, and has reached the present invention. As the ethylenically unsaturated compound which is the component (A) of the present invention, a radically polymerizable compound is usually used, and a monomer having a (meth) acryloyl group (hereinafter referred to as an acrylic monomer) is generally used. . Known acrylic monomers can be used. Moreover, the number average molecular weight of the acrylic monomers is 500 to 30,000.
The polyene compound can be used in combination.

The acrylic monomers used in the present invention are not particularly limited, but have a boiling point of 150 having at least one hydroxyl group or carboxyl group in the molecule.
(Meth) acrylates having a temperature of not lower than 0 ° C., or derivatives of these organic acid anhydrides or amines are preferably used. As the (meth) acrylates having one or more hydroxyl groups or carboxyl groups in the molecule and having a boiling point of 150 ° C. or more, all known compounds corresponding to these conditions can be used. For example, caprolactone-modified 2-hydroxyethyl methacrylate Alternatively, caprolactone-modified 2-hydroxyethyl acrylate (hereinafter, both of them will be abbreviated as caprolactone-modified 2-hydroxyethyl (meth) acrylate. Further, in the following description, all the description of (meth) acrylate is the combination of both acrylate and methacrylate. , Caprolactone-modified 2-hydroxypropyl (meth) acrylate, β-hydroxyethyl-β′-
Ethylene oxide modified phthalic acid (meth) acrylate such as acryloyloxyethyl phthalate, propylene oxide modified phthalic acid (meth) acrylate, 3
-Phenoxy-2-hydroxypropyl (meth) acrylate, 3-butoxy-2-hydroxypropyl (meth) acrylate, etc., or alkylene oxides, lactones adducts and acid anhydride adducts of these compounds with hydroxyl groups, such as di- 2-hydroxyethyl (meth) acrylate modified with caprolactone, 2-hydroxyethyl (meth) acrylate modified with tricaprolactone, β-hydroxydi (ethyleneoxy) ethyl-β'-acryloyloxyethyl phthalate, and 2-hydroxyethyl (meth ) Acrylate and phthalic anhydride or succinic acid adduct, and salts of (meth) acrylates having a carboxyl group in the above compound and a tertiary amine compound, but not limited to these.
It is also possible to use two or more types in combination.

The polyene compound having a number average molecular weight of 500 to 30,000 used together with the acrylic monomer component is generally known as a liquid rubber. Specifically, the number average molecular weight of substantially no crystallinity is 500 to 3,000.
0, preferably polybutadiene having a number average molecular weight of 500 to 5,000, polyisoprene having a number average molecular weight of 500 to 30,000, preferably 5,000 to 30,000, or a conjugated diene monomer such as butadiene, isoprene or pentadiene and olefins. Copolymers having a number average molecular weight of 500 to 30,000, and further modified products utilizing the reactivity of the end groups or molecular chains of these polyenes, intramolecular or terminal maleated products, epoxidized products, acryloyl or methacryloylated products, etc. are used. Particularly, ring-opened products of maleic anhydride-modified polyenes with alcohols, maleic acid-modified polyenes, and polyenes having a carboxyl group at the terminal are preferably used.

The amount of the ethylenically unsaturated compound (A) used is 2 to 80% by weight in the whole photosensitive resin composition, and 10 to 6%.
0% by weight, and further preferably 20 to 50% by weight. If the content is low, the mechanical flex life of the desired flexographic printing plate will be insufficient, and if it is high, the alcohol-containing ink resistance of the printing plate will be insufficient. When a polyene compound having a number average molecular weight of 500 to 30,000 is mixed with acrylic monomers, the amount of the polyene compound used is preferably 80% by weight or less, more preferably 70% by weight or less of the ethylenically unsaturated compound. is there. If it is more than 80% by weight, the water developability tends to be insufficient in practical use.

The carboxyl group-containing polyurethane which is the component (B) of the present invention includes, for example, polyisocyanate (a), polymer polyol (b), α, α-dimethylol monocarboxylic acid (c) and, if necessary, It can be obtained by reacting the chain extender (d) and / or the polymerization terminator (e) in a suitable organic solvent, and the number average molecular weight thereof is preferably 5,000 to 40,000.

Polyisocyanate (a) used here
Examples of the aliphatic diisocyanate include trimethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate and 1,3-butylene. Diisocyanate, 2,4,4-, or 2,
2,4-trimethylhexamethylene diisocyanate,
2,6-diisocyanate methyl caproate etc. can be mentioned.

Examples of the alicyclic diisocynate include 1,3-cyclopentane diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanate methyl-3,
5,5-trimethylcyclohexyl isocyanate,
4,4'-methylenebis (cyclohexyl isocyanate), methyl-2,4 cyclohexane diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, 1,4-bis (isocyanatomethyl) cyclohexane and the like can be mentioned.

Examples of the araliphatic diisocyanate include 1,3- or 1,4-xylylene diisocyanate, or a mixture thereof, ω, ω'-diisocyanate-1,4-diethylbenzene, 1,3- or 1,4. -Bis (1-isocyanate-1-methylethyl) benzene or a mixture thereof may be mentioned. Examples of aromatic diisocyanates include m-phenylene diisocyanate, p-phenylene diisocyanate, 4,
4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4- or 2,6-tolylene diisocyanate, 4,4'-toluidine diisocyanate,
4,4'-diphenyl ether diisocyanate etc. can be mentioned.

Examples of the derivatives of these isocyanate compounds include carbodiimide, uretdione, uretonimine, burette, allophanate and isocyanurate modified products. These may be used alone or as a mixture of two or more. The polymer polyol (b) is a polyether polyol, for example, one obtained by polymerizing or copolymerizing alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) and / or heterocyclic ether (tetrahydrofuran, etc.).

Specifically, polyethylene glycol, polypropylene glycol, polyethylene-polypropylene glycol (block or random), polyethylene-
Tetramethylene glycol (block or random),
Polyester polyols such as polytetramethylene ether glycol and polyhexane methylene ether glycol, for example, those obtained by polycondensing a divalent carboxylic acid and a low molecular weight polyol.

Specific examples of the saturated aliphatic dicarboxylic acid include oxalic acid, malonic acid, succinic acid, methylsuccinic acid, glutaric acid, adipic acid, 1,1-dimethyl-1,3-dicarboxypropane, 3-Methyl-3-ethylglutaric acid, azelaic acid, sebacic acid, other aliphatic dicarboxylic acids (C11-13), het acid and acid anhydrides of these carboxylic acids, that is, oxalic anhydride and succinic anhydride , Anhydrous 2-alkyl (C12-18)
Examples thereof include succinic acid and acid halides composed of these carboxylic acids, that is, oxalic acid dichloride, adipic acid dichloride, sebacic acid dichloride and the like.

Examples of the aliphatic unsaturated dicarboxylic acid include maleic acid, fumaric acid, itaconic acid, 1-butene-
2,4-dicarboxylic acid (also known as 2-methylene glutaric acid), alkenyl (C1-50) -substituted succinic acid, 2-alkenyl-substituted (C8-50) succinic acid, 1-alkyl (or alkenyl, C8-24) -1 -Pentene-4,
5-dicarboxylic acid, and acid anhydrides thereof, namely maleic anhydride, itaconic anhydride, 1,2-dimethylmaleic anhydride, succinic anhydride of alkenyl (C8-50), and 2- (1-octadecenyl anhydride. Examples thereof include succinic acid, tetrahydrophthalic anhydride, 3-methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, and fumaric acid dichloride which is an acid halide.

Examples of the aromatic divalent carboxylic acid include orthophthalic acid, isophthalic acid, terephthalic acid, toluene dicarboxylic acid, phthalic anhydride, benzylcarboxylic acid chloride and isophthalic acid chloride. Examples of the dihydric alcohol include ethylene glycol, propanediol, 1,4-butylene glycol, 1,3-butylene glycol, 1,2-butylene glycol, 1,6-hexanediol, neopentyl glycol and alkane (C7-22). ) Diol, diethylene glycol, triethylene glycol, dipropylene glycol, cyclohexanedimethanol, alkane-
1,2-diol (C17-20), hydrogenated bisphenol A, 1,4-dihydroxy-2-butene, 2,6-
Examples thereof include dimethyl-1-octene-3,8-diol, bisphenol A and glycerin monoallyl ether.

Examples of the trihydric alcohol include glycerin, 2-methyl-2-hydroxymethyl-1,3-propanediol, 2,4-dihydroxy-3-hydroxymethylpentane, 1,2,6-hexanetriol,
1,1,1, -tris (hydroxymethyl) propane,
2,2-bis (hydroxymethyl) -3-butanol,
And other aliphatic triols (C8-24) and the like. Polylactone polyols such as polycaprolactone diols or triols, poly-3-
Methylvalerolactone diol, etc. Polycarbonate polyols such as polyhexamethylene carbonate diol. Examples include polyolefin polyols such as polybutadiene glycol, polyisoprene glycol or hydrides thereof, and mixtures of two or more thereof.

Each of the polymeric polyol components may be used alone or as a mixture of two or more kinds, and the molecular weight thereof is usually 500 to 5000, preferably 1000 to 3.
000. The α, α-dimethylolmonocarboxylic acid (c) is a component for making a carboxyl group pendant from the resin skeleton in order to allow later water development within a practical range as a plate material, and specific examples include α, α. -Dimethylol acetic acid, α, α-dimethylol propionic acid,
Examples include α, α-dimethylol butyric acid.

The equivalent ratio of the polyisocyanate (a) to the polymer polyol (b) is usually 10.0 to 0.5,
It can be preferably used in the range of 6.0 to 1.0. If this equivalent ratio exceeds 10.0, the resin composition becomes hard and cannot be suitably used as a plate material. The amount of α, α-dimethylolmonocarboxylic acid (c) is 0.3 to 10% by weight, preferably 1 to 10% in the urethane prepolymer formed by reacting (a) to (e) as a carboxyl group (—COOH). It can be used in the range of up to 5% by weight. When the carboxyl group content is less than 0.3% by weight, it is difficult to obtain water developability within a practical range in the later plate making stage, and when it exceeds 10% by weight, the polymer has high hydrophilicity and a high water swelling rate,
It is not preferable because the suitability for water-based ink is reduced.

When producing the component (B), a chain extender (d) may be used if necessary. As the chain extender (d), the aforementioned low molecular weight glycols can be used alone or as a mixture of two or more kinds. When a chain extender is used, the equivalent ratio (a) / (d) to the above polyisocyanate (a) is preferably 2 or more. (A)
When / (d) is less than 2, it is not preferable because the hard segment portion in the resin component is too much and the hardness becomes high.

Further, if necessary, the polymerization terminator (e) may be a low molecular weight monoalcohol (methanol, ethanol,
Butanol, cyclohexanol, etc.) may also be used. The carboxyl group-containing urethane (B) of the present invention can be produced by a well-known method such as bulk polymerization or solution polymerization, and preferably the usual solution polymerization method of a thermoplastic polyurethane resin shown below can be mentioned.

That is, in the presence of an organic solvent, the following (a),
(B), (c) If necessary, (d) and / or (e) are reacted by a multistep method. At this time, the reaction temperature is not higher than the boiling point of the solvent and is 20 to 150 ° C, preferably 50 to 120 ° C. In order to accelerate the reaction,
Tin-based catalysts used in the urethanization reaction (for example, stannas octoate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin mercaptide, dibutyltin thiocarboxylate, dibutyltin dimaleate, dioctyltin mercaptide, dioctyltin thiol) Carboxylate etc.) can be used.

The organic solvent preferably has no active hydrogen, the component (c) is soluble, and has a relatively low boiling point. Specifically, acetone, methyl ethyl ketone, tetrahydrofuran, dioxane, Examples thereof include ethyl acetate and butyl acetate. The polyurethane having a carboxyl group as the component (B) is preferably used in the range of 1 to 100 parts by weight, more preferably 5 to 70 parts by weight, based on 100 parts by weight of the ethylenically unsaturated compound. When the amount used is less than 1 part by weight, flexibility is often insufficiently imparted to the printing plate, and when it is more than 100 parts by weight, the water swelling rate of the printing plate becomes large and the suitability for water-based ink decreases. It is not preferable because it is large.

The gelling agent, which is the component (C) of the present invention, has the property of gelling the composition and includes 12-hydroxystearic acid, benzylidene sorbitols,
Benzylidene xylitols and N-acylamine acid derivatives are preferably used, and a single compound or a plurality of compounds are used in combination. As a result, the shape retention of the photosensitive resin composition becomes practical.

Specifically, 12-hydroxystearic acid, 1,3: 2,4-dibenzylidene sorbitol,
1,3: 2,4: 5,6-tribenzylidene sorbitol, 1,3: 2,4-p-p'-ditoluylidene sorbitol, 1,3: 2,4-4-p-p'-diethyl benzylidene sorbitol , 1,3: 2,4-dibenzylidene xylitol, N-lauroyl-L-glutamic acid-α,
γ-di-n-butylamide is a typical compound, and the amount of these (C) component compounds used is within the range of 0.1 to 20 parts by weight with respect to 100 parts by weight of the ethylenically unsaturated compound component. If the amount used is less than 0.1 parts by weight, the shape retention of the desired flexographic printing plate material becomes insufficient, and if it is more than 20 parts by weight, the printing durability of the obtained printing plate tends to be poor. .

As the photopolymerization initiator which is the component (D) of the present invention, all conventionally known compounds can be used. For example,
Examples thereof include benzoin alkyl ethers, benzophenones, anthraquinones, benzyls, acetophenones and diacetyls. These photopolymerization initiators can be used in the range of 0.01 to 10 parts by weight with respect to 100 of the ethylenically unsaturated compound, and if the amount is less than 0.01 parts by weight, the photocurability will be insufficient. If the amount is more than the amount by weight, the mechanical printing durability of the printing plate tends to be insufficient.

In the photosensitive resin composition of the present invention, the component (C) basically functions as a gelling agent, but if necessary, it may be used as a polymer gelling aid. Polymer components can be used in combination. As such a polymer, a polymer having a number average molecular weight of 10,000 or more and having a functional group or bond which produces a strong hydrogen bond between molecules such as an amide bond, a hydroxyl group and a carboxyl group in the molecule or a polymer having a partial crystallinity is used. Copolymerized polyamides, especially polyether ester amides or polyether amides having polyethylene oxide segments, can be used, if desired, in particular for the purposes of the invention.

The photosensitive resin composition of the present invention may contain a thermoplastic resin soluble in the component (A), if necessary, to impart flexibility to the printing plate. The thermoplastic resin is not particularly limited, but is a raw material rubber or elastomer such as nitrile rubber, butyl rubber, acrylic rubber, epichlorohydrin rubber, silicone rubber, urethane rubber, ethylene-propylene copolymer, ethylene-
Examples thereof include copolymers of olefins such as vinyl acetate copolymer.

The photosensitive resin composition of the present invention may contain a plasticizer component such as alkylbenzene sulfonamides, alkylene glycols, glycerins, tertiary amine compounds and liquid polyolefins, if necessary. The tertiary amine compound is not particularly limited, but a compound having a (meth) acryloyl group in a stock solution preparation step of the photosensitive resin composition of the present invention using a primary amine or a secondary amine as a reactive additive component. A method of reacting with a compound to give a tertiary amine is particularly preferably used.

The structure of the final tertiary amine compound in the photosensitive resin composition of the present invention is a polyvalent amine having at least one hydroxyl group in the molecule and having a molecular weight of 300 or more, preferably 700 or more. Specifically, specifically, isophoronediamine, metaxylylenediamine, triethylenetetramine, diethylenetriamine, α, ω-diaminopoly (alkylene glycol), an acrylate adduct from dimer acid amidoamine, and the like are preferably used. At least a part of these tertiary amine compounds may have a carboxylate salt structure in the photosensitive resin composition.

A polymerization inhibitor (E) may be added to increase the thermal stability of the photosensitive resin composition of the present invention. Preferable polymerization inhibitors include phenols, hydroquinones, catechols, and phenothiazine. These heat stabilizers can be used in the range of 0.001 to 5% by weight based on the total composition. Other additives such as dyes, pigments, surfactants, defoamers, ultraviolet absorbers, and fragrances can be added.

As a method for producing the photosensitive resin composition of the present invention, first, a resin component is added to an ethylenically unsaturated compound obtained by mixing a liquid component such as a heat stabilizer and a plasticizer, and the mixture is stirred at 70 to 70%. After heating and heating to 200 ° C., preferably 100 to 180 ° C. to dissolve the resin component, the photopolymerization initiator and other additive components are mixed and dissolved to produce a substantially solvent-free solution. A reactive plasticizer component may be added at this stage. This solution can be cast, cast, or cooled to directly obtain a molded product. The photosensitive resin composition of the present invention is characterized by being a substantially thermoreversible gel, is a solid having practical strength at room temperature, and becomes a liquid having a relatively low viscosity when heated. Therefore, an easy molding method utilizing this characteristic can be applied. The photosensitive resin composition of the present invention can be designed to be a liquid having a poise of 100 poise or less at 150 ° C., and further a liquid having a poise of 100 poise or less at 120 ° C.

In order to form a printing plate material using the photosensitive resin composition of the present invention, for example, a solution of the composition is directly cast on a support or a cover film to form a sheet. You can If necessary, when a solvent is used, dry film formation may be performed, but since it is usually molded without a solvent, a photosensitive resin sheet can be produced only by cooling, and a thick resin film can be formed. Molding is also easy. In order to improve the adhesion to the negative film, it is preferable to form a thin film layer mainly made of a water-soluble or dispersible resin on the upper surface of the photosensitive resin sheet.

As the support, a metal plate such as steel, stainless steel, aluminum or copper having an adhesive layer if necessary, a plastic sheet such as a polyester film, a synthetic rubber sheet or the like is used, and a photosensitive resin composition is usually used. It is formed to a thickness of 0.1 to 10 mm. In order to form a relief image for printing using the photosensitive resin composition of the present invention, a negative or positive original image film is adhered onto the photosensitive resin composition prepared as described above, and usually 300 to 450 mμ. UV rays from high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, xenon lamps, chemical lamps, carbonace lamps, etc., centered on the wavelength, are irradiated to cure them by photoreaction. Then, the uncured portion is eluted or dispersed in water using a spray type developing device or a brush type developing device to form a relief on the support. If necessary, dry it in the air,
Alternatively, for example, flexographic printing can be obtained by performing actinic ray treatment in vacuum.

[0038]

EXAMPLES The present invention will be described in detail below with reference to examples. The number of parts used in the following examples is part by weight, and the number average molecular weight unless otherwise specified is the value determined by the GPC method.

Synthesis Example B-1 Tolylene diisocyanate (TDI-80) was placed in a 2-liter flask equipped with a thermometer, a condenser and a stirrer.
Takeda Pharmaceutical Co., Ltd. "Takenate" 80) 10
3.2 g, dimethylolpropionic acid (DMPA) 5
2.9 g and 180 g of methyl ethyl ketone (MEK)
And were charged and reacted at 75 ° C. for 1 hour to dissolve DMPA. To this, polytetramethylene glycol (PTMG2000 manufactured by Mitsubishi Kasei Co., Ltd., hydroxyl value 57.7 mg KO)
H / g) 383.9 g was added to carry out polymerization, and MEK 1080 g and urethanation catalyst stannas octoate (“Stannocto” manufactured by Yoshitomi Pharmaceutical Co., Ltd.) 180 mg were added in three portions as the polymerization viscosity increased. did. Finally 1
Polymerization was stopped by eliminating residual isocyanate with 15.5 g of butanol, solid content 30%, carboxyl group content 3.26% by weight (vs. solid content), solution viscosity at 25 ° C. 1
A pale yellow transparent resin solution of 420 cps was obtained. The molecular weight of the obtained resin is 1 in terms of polystyrene.
It was 1800 and the weight average molecular weight was 58,800.

Synthesis Example B-2 In the same manner as Synthesis Example B-1, TDI-80 113.7.
g, DMPA 52.7 g, PTMG2000 21
2.3 g, adipic acid / maleic anhydride / neopentyl glycol / 1,6-hexanediol unsaturated polyester (hydroxyl value 104.7 mg KOH / g, double bond equivalent 2394 g / ep) 161.4 g, MEK
1260 g, "Stanoct" 180 mg, and 1-butanol 17.0 g, solid content 30%, carboxyl group content 3.28 wt% (relative to solid content), double bond equivalent 801
0g / ep (relative to solid content), solution viscosity at 25 ° C 5600cp
s, number average molecular weight 22,000, weight average molecular weight 1330
00 urethane resin was obtained.

Synthesis Example B-3 In the same manner as Synthesis Example B-1, TDI-80 117.5.
g, DMPA 52.1 g, PTMG3000 (manufactured by Mitsubishi Kasei Co., Ltd., hydroxyl value 37.7 mg KOH / g) 103.
3g, "Takelac" P-21 (Takeda Pharmaceutical Co., Ltd.)
Made, bifunctional PPG, hydroxyl value 59.9 mg KOH / g) 2
A prepolymer having an isocyanate group content of 1.32% by weight was synthesized with 60.2 g and MEK 180 g, and the chain was extended with ethylene glycol 7.0 g. After that, MEK720g, "Stannoct" 180mg as the polymerization viscosity increases.
Was added in several times, the extension was stopped at 17.6 g of 1-butanol, the solid content was 37.5%, the carboxyl group content was 3.24% by weight (relative to the solid content), and the solution viscosity at 25 ° C. was 37.
00 cps, number average molecular weight 18,000, weight average molecular weight 1
26000 urethane resins were obtained.

Synthesis Example B-4 In the same manner as in Synthesis Example B-1, 4,4'-diphenylmethane diisocyanate (MDI) 134.3 g, DMPA.
47.9 g, PTMG2000 357.8 g, ME
K 1260 g, solid content 30%, carboxyl group content 2.98% by weight, solution viscosity at 25 ° C. 3480 cps
, Number average molecular weight 14500, weight average molecular weight 7660
A urethane resin of 0 was obtained.

Synthesis Example B-5 In the same manner as in Synthesis Example B-1, MDI 104.8 g, D
MPA 28.1g, PTMG2000 407.2
g, MEK 1260 g gave a urethane resin having a solid content of 30%, a carboxyl group content of 1.75 wt% (relative to solid content), a solution viscosity at 25 ° C. of 2950 cps, a number average molecular weight of 24600, and a weight average molecular weight of 86200.

Synthesis Example X-1 A copolyamide comprising the following components was synthesized according to a known formulation (for example, JP-A-55-79437).

Equimolar salt of ε-caprolactam / hexamethylenediamine and adipic acid / α, ω-diaminopropylpolyoxyethylene (number average molecular weight 1000) and equimolar salt of adipic acid = 20/20/60 The number average molecular weight of the copolymer polyamide was 33000 as determined by the terminal group quantification method of primary amino groups and carboxyl groups, which are the terminal groups. Synthesis Example X-2 1 mol of isophoronediamine as an additive component and 2-
An adduct of 1 mol of ethylhexyl glycidyl ether (reacted at 70 ° C. for 3 hours) was synthesized.

Example 1 60 parts of β-hydroxyethyl-β'-acryloyloxyethyl phthalate, 10 parts of caprolactone-modified 2-hydroxyethyl methacrylate, 20 parts of the carboxyl group-containing polyurethane obtained in Synthesis Example B-1, urethane rubber "Takelac" UR-E (manufactured by Takeda Pharmaceutical Co., Ltd.)
5 parts, 0.1 parts of heat stabilizer hydroquinone are mixed and heated,
After the temperature was raised and the mixture was stirred at 105 ° C. for 1 hour, 5 parts of α, ω-diaminopoly (propylene oxide) was added, and the mixture was further stirred at 140 ° C. for 20 minutes and then 1.5 parts of benzyl dimethyl ketal as a photopolymerization initiator, 3 parts of carboxylated tetra (oxyethylene) lauryl ether as a surfactant component, 3 parts of dibenzylidene sorbitol as a gelling agent component, N-lauroyl-L-glutamic acid-
2 parts of α-γ-di-n-butyramide were added and dissolved.
The solution thus obtained was cast on a polyester substrate having a thickness of 100 μ, which had been coated and cured with a polyester adhesive in advance, so that the photosensitive layer had a thickness of 3000 μ, coated, and allowed to stand at room temperature. And the compression strength of the raw plate is 3kg / cm
A solid photosensitive resin printing plate material of No. ² was obtained.

On the photosensitive layer of this printing plate material, a gray scale negative film for measuring sensitivity (manufactured by Stouffer, 21Steps
Sensitivity Guide) and negative film for image reproducibility evaluation (150 lines 3%, 5%, 10% halftone dots, diameters 200μ, 300μ independent points, width 50 and 70μ thin lines are) vacuum-contacted and 2KW ultra high pressure mercury lamp Was exposed for 3 minutes from a distance of 1 m.

After completion of the exposure, development was carried out with a brush type washing machine (liquid temperature 30 ° C.) containing neutral water. Development time 10
In minutes, a relief image with a depth of 700 μ was formed. As a result of evaluating this relief image, it was found that the gray scale portion remained up to 13 steps, and the image portion reproduced almost completely 5% halftone dots, 300μ independent points, 50μ fine lines and the like. The hardness of the printing plate was Shore A hardness of 65 after the completion of post-exposure of actinic rays. Using this printing plate, a flexographic printing test was performed on 100,000 sheets using a water-based ink, and good printed matter was obtained. Comparative Example 1 In Example 1, dibenzylidene sorbitol, N-
A photosensitive resin printing plate material was similarly obtained without using lauroyl-L-glutamic acid-α / γ-di-n-butyramide, but the compression strength of this raw plate material was less than 1 kg / cm ² , so handling was performed. It was poor in properties and did not have practical strength as a solid printing plate material. Example 2 "M3000-20", which is an addition product of 1 mol of maleic anhydride to 1 mol of polybutadiene having a number average molecular weight of 3000.
(Nippon Petrochemical Co., Ltd.) 20 parts, β-hydroxyethyl β′-acryloyloxyethyl phthalate 25 parts,
20 parts of caprolactone-modified 2-hydroxyethylmethacrylate, 7 parts of polyetheramide obtained in Synthesis Example X-1, 20 parts of polyurethane obtained in Synthesis Example B-2,
Heat stabilizer Hydroquinone (0.05 parts) was mixed, heated, heated, stirred at 105 ° C. for 1 hour, added with 10 parts of the additive shown in Synthesis Example X-2, and further stirred at 140 ° C. for 20 minutes. 1.5 parts of benzyl dimethyl ketal as a photopolymerization initiator, 4 parts of 12-hydroxystearic acid as a gelling agent component, 6.5 parts of dibenzylidene sorbitol,
N-lauroyl-L-glutamic acid-α · γ-di-n-
2 parts of butyramide were added and dissolved. The solution thus obtained was cast onto a 100 μm-thick polyester substrate on which a polyester-based adhesive had been applied and cured in advance so that the photosensitive layer had a thickness of 3000 μm, and the mixture was allowed to stand at room temperature. Thus, a solid photosensitive resin printing plate material was obtained.

This printing plate material was exposed for 20 seconds from a distance of 15 cm by an exposure device in which 15 20 W chemical lamps were arranged side by side. Then, on the photosensitive layer, a grayscale negative film for sensitivity measurement (manufactured by Stouffer, 21Steps Sensitiv
City Guide) and negative film for image reproducibility evaluation (150
Lines 3%, 5%, 10 dots, diameter 200μ, and 300μ
Separate points, widths 50 and 70 thin lines are attached in vacuum,
Exposure was performed for 10 minutes from a distance of 15 cm with an exposure device in which 15 20 W chemical lamps were lined up. After completion of the exposure, development was performed with a brush type washing machine (liquid temperature 30 ° C.) containing neutral water. A relief image having a depth of 700 μ was formed at a developing time of 5 minutes.

As a result of evaluating this relief image, the gray scale part remains up to 14 steps, and the image part is 5%.
It was found that halftone dots, 300μ independent points, 50μ thin lines, etc. were almost completely reproduced. The printing plate had a Shore A hardness of 57 after the end of exposure to actinic radiation. Using this printing plate, a flexographic printing test was performed on 100,000 sheets using a water-based ink containing 20% of an alcohol solvent, and a good printed matter was obtained. Comparative Example 2 A photosensitive resin plate material was obtained in the same manner as in Example 2 except that the B-2 component was 0 part. When exposure and development were carried out in the same manner as in Example 2, a relief image having a depth of 700 μm was obtained with a development time of 5 minutes. The gray scale part remains up to 14.5 steps, and the image part is 5% halftone dot, 300μ independent point, 5
A printing plate in which 0 μ fine lines and the like were almost completely reproduced was obtained.
The hardness of the printing plate was Shore A hardness 67 after the completion of post-exposure with actinic rays.

Using this printing plate, a flexographic printing test was carried out using a water-based ink, but from around 30,000 sheets, the image area of the printing plate was chipped. It is considered that since the B-2 component was not added, the flexibility of the printing plate was insufficient and the printing durability was lowered. Example 3 In Example 1, 30 parts of the carboxyl group-containing polyurethane of Synthesis Example B-3 was used instead of 20 parts of the carboxyl group-containing polyurethane of Synthesis Example B-1, and 5 parts of α, ω-diaminopoly (propylene oxide) was used. Synthesis Example X
A flexographic printing plate was obtained in the same manner as in Example 1 by using -2 and 10 parts. When exposed to the same exposure conditions as in Example 1 and developed with a brush type washing machine (liquid temperature 30 ° C.) containing neutral water, a relief image of 700 μ was formed in a developing time of 7 minutes.

When this relief image was evaluated, the grayscale portion remained until 14 steps and the remaining image was 5% halftone dot, 30
Almost 0μ independent points and 50μ thin lines were reproduced. The hardness of the printing plate is Shore A hardness 6 after the post-exposure of actinic rays.
It was 3. This printing plate was used with water-based ink 1
A flexographic printing test of 00000 sheets was performed, and good printed matter was obtained. Example 4 A flexographic printing plate was prepared in the same manner as in Example 1 except that 20 parts of the carboxyl group-containing polyurethane of Synthesis Example B-4 was used instead of 30 parts of the carboxyl group-containing polyurethane of Synthesis Example B-3. Obtained. When exposed to the same exposure conditions as in Example 1 and developed with a brush type washing machine (liquid temperature 30 ° C.) containing neutral water, a relief image of 700 μ was formed in a developing time of 7 minutes.

When this relief image was evaluated, the grayscale part remained in 14 steps until the remaining image was 5% halftone dot, 30%
Almost 0μ independent points and 50μ thin lines were reproduced. The hardness of the printing plate is Shore A hardness 6 after the post-exposure of actinic rays.
It was 7. Using this printing plate, a flexographic printing test was performed on 100,000 sheets using a water-based ink, and good printed matter was obtained. Example 5 A flexographic printing plate was obtained in the same manner as in Example 1 except that 20 parts of the polyurethane of Synthesis Example B-5 was used instead of 20 parts of the polyurethane containing the carboxyl group of Synthesis Example B-1. When exposed under the same exposure conditions as in Example 1 and developed with a brush washing machine (liquid temperature 30 ° C.) containing neutral water, a relief image of 700 μ was formed in a developing time of 30 minutes.

When this relief image was evaluated, the grayscale portion remained in 14 steps until the remaining image was 5% halftone dot, 30
Almost 0μ independent points and 50μ thin lines were reproduced. The hardness of the printing plate is Shore A hardness 5 after the post-exposure of actinic rays.
It was 9. Using this printing plate, a flexographic printing test was performed on 100,000 sheets using a water-based ink, and good printed matter was obtained.

[0055]

EFFECT OF THE INVENTION Since the present invention is constituted as described above, in a flexographic printing using a water-based ink or other flexographic ink, a photosensitive resin composition which gives a flexographic printing plate having excellent printing resistance and flexibility is provided. Obtainable.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location G03F 7/031 7/035 (72) Inventor Masakazu Masui 4-1-402 Izumi-cho, Takarazuka-shi, Hyogo (72) Inventor Fumiaki Hirata 3-39-22 Mozumoumecho, Sakai City, Osaka Prefecture

Claims (4)

[Claims] 1. The following (A), (B), (C) and (D)
A photosensitive resin composition for a printing plate containing a component. (A) Ethylenically unsaturated compound (B) Carboxyl group-containing polyurethane (C) Gelling agent (D) Photopolymerization initiator 2. The printing plate according to claim 1, wherein the component (C) is at least one compound selected from the group consisting of 12-hydroxystearic acid, benzylidene sorbitols, benzylidene xylitols, and N-acylamine acid derivatives. Photosensitive resin composition for use. 3. With respect to 100 parts by weight of the component (A),
The component (B) is 1 to 100 parts by weight, and the component (C) is 0.1 to 0.1 parts by weight.
The photosensitive resin composition for a printing plate according to claim 1 or 2, wherein 20 parts by weight and the component (D) are 0.01 to 10 parts by weight. 4. A printing plate original plate comprising a sheet of the printing plate photosensitive resin composition according to any one of claims 1 to 3.