JPH06250388A - Photosensitive resin composition and flexographic master plate using that - Google Patents

Abstract

PURPOSE:To provide a photosensitive resin compsn. which can be developed with water and has characteristics required for flexographic printing plate. CONSTITUTION:The photosensitive resin compsn. contains reactive microgel (1), compd. having alpha,beta-ethylene unsatd. double bonds (2), and rubber or thermoplastic elastomer (3). The reactive microgel (1) is obtd. by the reaction of microgel fine particles (A) and a compd. (B) having epoxy groups and at least one alpha,beta-ethylene type unsatd. double bond. The microgel fine particles are synthesized by emulsion polymn. of a compd. having alpha,beta-ethylene type unsatd. double bonds with a carboxyl group-contg. compd. as an emulsifier. The flexographic master plate is produced by using this photosensitive resin compsn. Thereby, by using this photosenstive resin compsn., such a flexographic plate that has significantly improved fracture strength, fracture elongation, rubber hardness, etc., and can be developed with water, can be produced.

Description

Detailed Description of the Invention

The present invention relates to a reactive microgel having an α, β-ethylenically unsaturated double bond on the surface of particles.
(1) a photosensitive resin composition containing a compound (2) having an α, β-ethylenically unsaturated double bond, and a rubber or a thermoplastic elastomer (3), and further using the photosensitive resin composition Regarding flexographic printing original plate.

[0001]

2. Description of the Related Art Conventionally, in the field of printing, offset printing,
Gravure printing, flexographic printing and screen printing have been mainly used. In Japan, offset printing is used for mass printing of newspapers and magazines, and gravure printing has been mainly used for color gravure and color printing.
However, flexo printing has become popular with the modernization of packaging. For example, corrugated paper, container paper,
Printing on leaflets, wrapping paper bags, wrapping films, etc. In these fields, the size of one lot is not as large as that of newspapers and magazines, and the accuracy is not so required in color printing. With the development of flexographic printing technology, it has come to be used also in the printing field that requires high precision other than the above.

[0002] In the conventional method for producing a flexographic printing plate, the steps of (a) preparation of a metal plate, (b) mold making, and (c) vulcanization of raw rubber are required, which requires skill and a long time. Therefore, there are two drawbacks, that is, the cost is considerably high, and a plate with high precision cannot be produced. As a solution to these drawbacks, a solvent-developable photosensitive resin plate has been developed, and it has become possible to easily prepare a flexographic printing plate. However, since these plates use a diene rubber such as polybutadiene as a base material, it is common to use a halogen solvent such as trichloroethane or perchlorethylene as a developing solution during development. These halogen-based solvents are beginning to be concerned about their effects on human health and the global environment.
Especially, in terms of the impact on the earth, it is said that it has a great impact on the global warming phenomenon together with CFCs, and some halogen-based solvents
Since 1996, there is a fear that it will not be usable. Under these circumstances, a flexographic printing plate that can be developed without using a halogen-based solvent, particularly a flexographic printing plate that can be developed only with water has been desired.

Therefore, as a result of the research conducted by the present inventors,
A flexographic printing plate containing a reactive microgel (disclosed in Japanese Patent Application Laid-Open No. 2-263805) in which an unsaturated double bond is introduced on the surface of microgel microparticles using a cationic reactive group is developed only with water. It has been found that the contradictory properties of being able to do and having water resistance can be compatible. However, expensive monomers such as dimethylaminoethylmethacrylate are used for the production of such cationic type reactive microgel, and the heat resistance of the flexographic printing plate is not good because it is a cationic type (redox reaction There is a problem such as).

[0004]

DISCLOSURE OF THE INVENTION The inventors of the present invention can produce a photosensitive resin composition containing an anion type reactive microgel at a low cost, and use the photosensitive resin composition for flexographic printing. It was found that the original plate can be developed with water alone and has good heat resistance, and the present invention has been completed.

[0005]

That is, the present invention is
a compound having an α, β-ethylenically unsaturated double bond,
Microgel fine particles (A) synthesized by emulsion polymerization using a carboxyl group-containing compound as an emulsifier, and a compound having an epoxy group and α, β-ethylenically unsaturated double bond (B)
Reactive microgel obtained by reacting with and (1), α, β-
Provided are a photosensitive resin composition containing a compound (2) having an ethylenically unsaturated double bond, and a rubber or a thermoplastic elastomer (3), and a flexographic printing original plate using the photosensitive resin composition.

Monofunctional compounds having an α, β-ethylenically unsaturated double bond include (a) (meth) acrylate compounds: methyl (meth) acrylate, ethyl (meth) acrylate, Propyl (meth) acrylate, Isopropyl (meth) acrylate,
Butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, lauryl (meth) acrylate, etc., C1-C18 alkyl ester of (meth) acrylic acid: allyl (meth) acrylate, etc. ) C2-C20 alkenyl ester of acrylic acid: C2-C20 hydroxylalkyl of (meth) acrylic acid such as hydroxylethyl (meth) acrylate, hydroxylethyl (meth) acrylate, hydroxypropyl (meth) acrylate and hydroxypropyl (meth) acrylate. Ester: C3 to C19 alkenyloxyl alkyl ester of (meth) acrylic acid such as allyloxylethyl (meth) acrylate: (meth) acrylic acid, ethylene glycol, propylene glycol, butane glycol, pentyl glycol , Polyethylene glycol,
Propylene glycol, polycaprolactone polyol, polyester polyol, acrylic polyol, butadiene glycol, isoprene glycol and other glycols are modified with diisocyanate and reacted with acrylic monomers having one OH group such as 2-hydroxyacrylate and 2-hydroxymethacrylate. (B) Vinyl aromatic compound: styrene, α-methylstyrene, vinyltoluene, p-chlorostyrene, etc. (c) Others: acrylonitrile, methacrylonitrile, methylisopropenyl ketone: vinyl acetate, Vinyl propionate etc. can be mentioned.

Next, as a polyfunctional compound having two or more functional groups for three-dimensionally crosslinking the inside of the microgel particles, trimethylolpropane tri (meth) acrylic acid ester and di (meta) of glycols can be used. ) Acrylic acid ester, di (meth) acrylic acid ester of polyol,
Examples thereof include (meth) acrylate compounds such as polyester di (meth) acrylic acid esters. Further, glycols such as ethylene glycol, propylene glycol, butane glycol, pentyl glycol, polyethylene glycol, propylene glycol, polycaprolactone polyol, polyester polyol, acrylic polyol, butadiene glycol, and isoprene glycol are modified with diisocyanate to prepare isocyanate groups at both ends of the molecule. Examples of the urethane compound include a urethane compound obtained by reacting with an acrylic monomer having one OH group. Furthermore, a compound having a functional group such as polybutadiene or polyisoprene having an epoxy group, an acid anhydride group or the like at the terminal or side chain, and an α, β-ethylenically unsaturated double bond, For example, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate and other C2 to C20 hydroxyalkyl esters, polydienes obtained by reacting allyl alcohol, allylamine, etc., and excessive amounts of hydroxyl groups at the terminals and side chains. Examples thereof include polydienes obtained by reacting a diisocyanate group and reacting the remaining isocyanate group with a hydroxyalkyl ester or allyl alcohol.

These compounds are appropriately selected according to the desired physical properties and may be used alone or in combination of two or more. However, when a monofunctional compound is used, it does not three-dimensionally crosslink by itself, and therefore it is necessary to use it in combination with a polyfunctional compound or to use a polyfunctional reactive emulsifier as an emulsifier described later. When the obtained reactive microgel is used as a flexographic printing plate material, it is desirable to use a urethane compound or a polydiene.

As the carboxyl group-containing compound, those having an effect as an emulsifier are usually used, in which the carboxyl group in the carboxyl group-containing compound is neutralized with an alkali metal, amines or ammonium to form a carboxylate salt. To be Among such emulsifiers, low molecular weight emulsifiers include saturated fatty acids such as caprylic acid, lauric acid, stearic acid, acrylic acid, methacrylic acid,
There are reaction products of reactive monomers such as maleic acid and itaconic acid with alkali metals, amines, ammonium and the like.

As the polymer emulsifier, a homopolymer of a reaction product of a reactive monomer having a carboxyl group such as acrylic acid, methacrylic acid, maleic acid or itaconic acid with an alkali metal, amines or ammonium, or Reaction products of the above reactive monomers with alkali metals, amines or ammonium, and other reactive monomers such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, (meth) acrylic C1 to C18 alkyl ester of (meth) acrylic acid such as butyl acid and hexyl (meth) acrylate: Glycidyl (meth) acrylate: C2 to C8 alkenyl ester of (meth) acrylic acid such as allyl (meth) acrylate: hydroxyethyl C2 to C8 of (meth) acrylic acid such as (meth) acrylate B alkoxyalkyl ester of (meth) allyl oxyl acrylate can choose those obtained by copolymerizing a selected vinyl monomers one or more of the like C3 ～C19 alkenyloxyl alkyl esters of acrylic acid. When a high molecular weight emulsifier is used, the reaction of a reactive monomer having a carboxyl group with an alkali metal, amines, ammonia or the like is carried out before homopolymerization or copolymerization with another vinyl monomer as shown above. Alternatively, it may be carried out after homopolymerization or copolymerization with another vinyl monomer.

Alkali metals used to neutralize these emulsifiers include sodium hydroxide, potassium hydroxide, calcium hydroxide and the like, and amines include monoethanolamine, diethanolamine, triethanolamine, Examples thereof include triethylamine, tributylamine, dimethyldodecylamine and the like. These emulsifiers are used as they are or as a reactive emulsifier in which an α, β-ethylenically unsaturated double bond is introduced by reacting an epoxy group such as glycidyl (meth) acrylate with a part of a carboxyl group. be able to. The polymeric emulsifier can control the degree of water solubility, and is therefore a preferred emulsifier in applications requiring water resistance.

Further, for the purpose of assisting the emulsification, an anionic system,
A nonionic low-molecular-weight surfactant may be used in combination with the above-mentioned polymer emulsifier as long as the physical properties such as water resistance are not impaired. Nonionic surfactants include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether,
Polyoxyethylene alkyl ether such as polyoxyethylene cetyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene derivative, oxyethylene
Examples thereof include sorbitan fatty acid esters such as oxypropylene block copolymer, sorbitan monolaurate, sorbitan monostearate, and sorbitan trioleate, glycerin fatty acid esters, and polyoxyethylene fatty acid esters.

Examples of the anionic surfactant include fatty acid salts such as sodium stearate and potassium oleate, sodium lauryl sulfate, triethanolamine lauryl sulfate, alkyl sulfates such as ammonium lauryl sulfate, alkylbenzene sulfonates, and alkylnaphthalene sulfone. Acid salt, alkyl sulfosuccinate,
Examples thereof include alkyl diphenyl ether disulphonate, alkyl phosphate, and polyoxyethylene alkyl sulfate ester salt.

These emulsifiers are used in an amount of 0.1 to 50% by weight, preferably 0.1 to 20% by weight, based on the compound having an α, β-ethylenically unsaturated double bond, and the emulsion polymerization temperature is 50%.
~ 95 ° C, preferably 65 ~ 80 ° C. Α during emulsion polymerization
The total solid content of the compound having a β-ethylenically unsaturated double bond and the emulsifier is 10 to 50% by weight, preferably 10 to 35% by weight. In the present invention, the particle size of the microgel fine particles (A) produced by emulsion polymerization is usually 0.01 to 200 μm as measured by the light scattering method.

The microgel fine particles (A) thus obtained have carboxyl groups on the surface, epoxy groups and α, β
-A reactive microgel having an α, β-ethylenically unsaturated double bond on the surface is produced by reacting with an epoxy group of the compound (B) having an ethylenically unsaturated double bond. Examples of the compound (B) having an epoxy group and an α, β-ethylenically unsaturated double bond include glycidyl (meth)
Acrylate, N-glycidyl acrylamide, glycidyl allyl ether, 1,2-epoxy-5-hexene, etc.,
An epoxy compound having at least one α, β-ethylenically unsaturated double bond may be mentioned. These compounds (B)
Are appropriately selected depending on the desired physical properties and can be used alone or in combination of two or more.

The compound (B) can be reacted at a free ratio of 1 to 100 mol% with respect to the carboxyl groups on the surface of the microgel. This reaction is carried out by mixing an epoxy compound in a microgel aqueous dispersion, and then at 30 to 90 ° C, preferably
Simply stir at a temperature of 60-80 ° C for 2 hours or more to finish.
As described above, the present invention has an advantage that the reaction can be performed even in an aqueous dispersion. The reactive microgel of the present invention is provided as an aqueous dispersion as it is, or as an organic solvent dispersion in which water is partially or wholly removed by azeotropic distillation with a solvent such as aromatic hydrocarbons, alcohols and ketones. . When it is desired to use it in a dry state, it can be made into powder by a usual drying method, preferably after coagulating the aqueous dispersion, washing the coagulated product, drying and finely pulverizing it, or spray drying. it can.

A compound having an α, β-ethylenically unsaturated double bond with respect to 100 parts by weight of the reactive microgel (1).
The photosensitive resin composition of the present invention can be obtained by mixing 1 to 200 parts by weight of (2) and 1 to 200 parts by weight of rubber or thermoplastic elastomer (3) (as solid content).
More preferably, the compound having an α, β-ethylenically unsaturated double bond with respect to 100 parts by weight of the reactive microgel.
1 to 100 parts by weight of (2) and 1 to 100 parts by weight of rubber or thermoplastic elastomer (3) are mixed.

As the compound (2) having an α, β-ethylenically unsaturated double bond, one or more kinds of monomers, oligomers and prepolymers can be used. For example, in the material of the core of the above-mentioned reactive microgel. The same compounds as those having a certain α, β-ethylenically unsaturated double bond can be mentioned.
Preferred are oligomers and prepolymers. Among these, a compound having flexibility, flexibility, toughness, rubber elasticity, etc. in the state after crosslinking and curing is preferable, and for example, a urethane compound having an α, β-ethylenically unsaturated double bond, a terminal or a side chain Examples thereof include polydienes having an α, β-ethylenically unsaturated double bond, that is, urethane acrylate and polybutadiene acrylate.

The rubber or thermoplastic elastomer (3) added for the purpose of supplementing rubber elasticity includes butadiene rubber, styrene-butadiene rubber, isoprene rubber and styrene-
Examples include isoprene rubber, neoprene rubber, acrylonitrile butadiene rubber, chloroprene rubber, acrylic rubber, urethane rubber, silicone rubber, raw rubber, urethane elastomer, and one or more of these rubbers are arbitrarily selected and used. be able to.

When the reactive microgel powder is used, these materials are mixed by a kneader, a two-roll, an extruder or the like. When an aqueous dispersion of reactive microgel is used, it may be mixed with an aqueous dispersion of styrene-butadiene rubber, isoprene rubber, urethane rubber or the like. Further, the photosensitive resin composition of the present invention may be mixed with a thermal polymerization inhibitor, a photoinitiator, an antioxidant if necessary, a colorant, an extender pigment, a slip agent,
An antifoaming agent may be added to the extent that the original properties are not impaired.

The photosensitive resin composition of the present invention is formed into a sheet having a thickness of about 1 to 8 mm by using a hot press, an extrusion molding machine, etc., and a base film and a cover film are provided on both sides of this sheet, if necessary. Thus, an original plate for flexographic printing is obtained. The negative film of the original is brought into close contact with the flexographic printing original plate and irradiated with ultraviolet rays for a certain period of time to cure the resin in the original plate. The negative film is peeled off, and the uncured portion of the original plate is washed off with a brush in water to obtain a flexographic printing plate having sufficient rubber elasticity.

[0022]

EXAMPLES The present invention will be described in more detail with reference to examples. In the examples, "part" and "%" mean "part by weight" and "% by weight", respectively. Before describing the examples, a synthesis example of each component used in the examples will be described. (Synthesis example a) Synthesis of polymeric emulsifier 90 parts of acrylic acid (70 mol% neutralized with sodium hydroxide),
10 parts of butyl acrylate and 400 parts of deionized water were heated to 80 ° C. in a nitrogen atmosphere while stirring in a 1 liter reaction vessel. Add 16 parts of 5% azobisamidinopropane dihydrochloride (hereinafter referred to as AAPD) aqueous solution, hold for 2 hours, and then add 5% AAPD.
After adding 4 parts of the aqueous solution, the reaction mixture was heated to 80 ° C after the addition was completed.
Polymerization was completed by holding for a period of time to obtain a non-reactive polymer emulsifier.

(Synthesis Example b) Synthesis of Reactive Polymer Emulsifier 100 parts of the polymer emulsifier obtained in Synthesis Example a and 14.6 parts of glycidyl methacrylate (hereinafter referred to as GMA) are stirred in a 1 liter reaction vessel at 80 The mixture was heated to ° C and reacted for 4 hours to obtain a reactive polymer emulsifier.

(Synthesis Example c) Synthesis of Reactive Microgel 95 parts of styrene, 5 parts of divinylbenzene, 250 parts of polymer emulsifier synthesized in Synthesis Example a (solid content adjusted to 20%), 250 parts of deionized water In a 1 liter reaction vessel, the mixture was heated to 80 ° C. in a nitrogen atmosphere while stirring. 16 parts of 5% AAPD aqueous solution was added and kept for 2 hours, then 4 parts of 5% AAPD aqueous solution was added, and after the addition was completed, the reaction mixture was kept at 80 ° C for 4 hours to complete the polymerization, and the non-reactive micro An aqueous gel dispersion was obtained. The microgel particle size in the dispersion was measured by the light scattering method to be about 80.
was nm. After leaving the obtained non-reactive microgel aqueous dispersion overnight, 14.6 parts of glycidyl methacrylate was added, and the mixture was heated to 80 ° C in an air atmosphere and stirred for 4 hours to give α to the surface of the microgel. A reactive microgel aqueous dispersion having a β-ethylenically unsaturated double bond was obtained.

(Synthesis Example d) Synthesis of Reactive Microgel 100 parts of dimethacrylate modified polybutadiene (“R-45ACR-LC” manufactured by Idemitsu Petrochemical Co., Ltd.), nonionic surfactant (“Emulgen 810” manufactured by Kao Corporation) ) 10 parts, 100 parts of the polymeric emulsifier synthesized in Synthesis Example a (solid content adjusted to 20%), and 284 parts of deionized water were heated to 80 ° C. in a 1 liter reaction vessel with stirring in a nitrogen atmosphere. . 16 parts of 5% AAPD aqueous solution was added and kept for 2 hours, then 4 parts of 5% AAPD aqueous solution was added, and after the addition was completed, the reaction mixture was kept at 80 ° C for 4 hours to complete the polymerization, and the non-reactive micro An aqueous gel dispersion was obtained. The measurement result of the microgel particle size in the dispersion by the light scattering method is about 2
It was 00 nm. After leaving the obtained non-reactive microgel aqueous dispersion overnight, 5.9 parts of glycidyl methacrylate was added, and the mixture was heated to 80 ° C in an air atmosphere and stirred for 4 hours to prepare the reactive microgel aqueous dispersion. A liquid was obtained.

Synthesis Example e) Synthesis of Reactive Microgel Instead of the polymer emulsifier synthesized in Synthesis Example a, Synthesis Example b
A non-reactive microgel aqueous dispersion was obtained in the same manner as in Synthesis Example d, except that the reactive polymer emulsifier synthesized in (3) was used. The measurement result of the particle size of the microgel in the dispersion liquid by the light scattering method was about 200 nm. After leaving the obtained non-reactive microgel aqueous dispersion overnight, 2 parts of glycidyl methacrylate was added, and the mixture was heated to 80 ° C in an air atmosphere and heated to 4 ° C.
A reactive microgel aqueous dispersion was obtained by stirring for an hour.

(Synthesis Example f) Synthesis of non-reactive microgel 100 parts of "R-45ACR-LC", 10 parts of "Emulgen 810", 100 parts of polymeric emulsifier synthesized in Synthesis Example b (solid content 20%) (Preparation), 290 parts of deionized water was heated to 80 ° C. in a nitrogen atmosphere while stirring in a 1 liter reaction vessel. 16% 5% AAPD aqueous solution
1 part of the solution and kept for 2 hours, then 4 parts of 5% AAPD aqueous solution was added, and after the addition was completed, the reaction mixture was kept at 80 ° C. for 4 hours to complete the polymerization, and a non-reactive microgel aqueous dispersion was obtained. It was
The measurement result of the particle size of the microgel in the dispersion liquid by the light scattering method was about 200 nm.

(Synthesis example g) Synthesis of urethane methacrylate 100 parts of polyester diol having a molecular weight of 1000 obtained by polycondensation reaction of butanediol and adipic acid, 75 parts of diphenylmethane diisocyanate and 0.1 part of tin octenoate are mixed and mixed in a flask. After reacting at 60 ° C. for 30 minutes and then at 80 ° C. for 4 hours, 26 parts of 2-hydroxyethyl methacrylate was added and further reacted at 80 ° C. for 3 hours to obtain urethane methacrylate.

(Example 1) The reactive microgel aqueous dispersion prepared in Synthesis Example c was placed in a vat and dried in an oven at 50 ° C for 1 day to obtain a microgel powder. 60 parts of the obtained microgel powder, 20 parts of urethane methacrylate synthesized in Synthesis Example g, 20 parts of polybutadiene rubber (“JSR BR02LL” manufactured by Japan Synthetic Rubber Co., Ltd.) and a photoinitiator (“Darocurure 2959” manufactured by Merck) 5 The parts were dispersed with a two-roll mill to obtain a microgel mixture. The obtained microgel mixture was formed into a uniform film having a thickness of about 3 mm under the conditions of 50 ° C. and 100 Kg / cm ² with a pressing machine.

Example 2 The procedure of Example 1 was repeated except that the reactive microgel synthesized in Synthesis Example c was replaced with the reactive microgel synthesized in Synthesis Example c. A uniform film was obtained. (Example 3) A uniform film having a thickness of about 3 mm was obtained in the same manner as in Example 1 except that the reactive microgel synthesized in Synthesis Example e was used instead of the reactive microgel synthesized in Synthesis Example c. Got

Example 4 A uniform thickness of about 3 mm was obtained in the same manner as in Example 2 except that polybutadiene diacrylate (“M-1000-80” manufactured by Idemitsu Petrochemical Co., Ltd.) was used instead of urethane methacrylate. A film was obtained. (Example 5) Instead of urethane methacrylate, "M-10
A uniform film having a thickness of about 3 mm was obtained in the same manner as in Example 3 except that "00-80" was used.

Example 6 A styrene / isoprene / styrene block copolymer (“Clayton D1320X” manufactured by Shell Chemical Co.) was used in place of “JSR BR02LL”.
A uniform film having a thickness of about 3 mm was obtained in the same manner as in Example 3. (Example 7) Instead of "JSR BR02LL", "Clayton D1"
The thickness is about 3 in the same manner as in Example 5 except that "320X" is used.
A uniform film of mm was obtained.

Comparative Example 1 A resin mixture was obtained in the same manner as in Example 1 except that the reactive microgel powder was removed in Example 1. The resin mixture thus obtained was formed into a uniform film having a thickness of about 3 mm under the conditions of 50 ° C. and 100 Kg / cm ² with a press. Comparative Example 2 A uniform thin film having a thickness of about 3 mm was prepared in the same manner as in Example 1 except that the non-reactive microgel synthesized in Synthesis Example f was used in place of the reactive microgel synthesized in Synthesis Example c. A film was obtained.

(Comparative Example 3) A uniform film having a thickness of about 3 mm was obtained in the same manner as in Comparative Example 1 except that "M-1000-80" was used instead of urethane methacrylate. (Comparative Example 4) Instead of "JSR BR02LL", "Clayton D1"
The thickness is about 3 in the same manner as in Comparative Example 1 except that "320X" is used.
A uniform film of mm was obtained.

(Evaluation of physical properties of flexographic printing plate material) The films obtained in Examples 1 to 7 and Comparative Examples 1 to 3 were irradiated with ultraviolet rays of 4000 mJ / cm ² to obtain cured films. The results of measuring the tensile strength, elongation, rubber hardness, water resistance, and IPA (isopropyl alcohol resistance) of this cured film at 25 ° C are shown in Table 1.
Shown in. Tensile strength: Cut to a width of 10 mm, and measured with a tensile tester under conditions of a tensile speed of 50 mm / min. Rubber hardness: Measured according to JIS-K6301. Water resistance: 24 in each ion-exchanged water and IPA
It was evaluated by immersing it for a period of time and measuring its swelling / IPA resistance rate. Swelling rate = ((weight after soaking for 24 hours / weight before soaking) -1) * 10
0 resolution: The thinnest line width obtained by overlaying a film for a mask having a pattern of various line widths on the film and irradiating with the above ultraviolet rays and developing with water was defined as the resolution.

[0036]

[Table 1]

[0037]

According to the present invention, a flexographic printing plate material which can be cured with high sensitivity and whose uncured portion can be developed with water alone can be obtained at low cost.

Claims (2)

[Claims] 1. Microgel fine particles (A) prepared by emulsion polymerization of a compound having an α, β-ethylenically unsaturated double bond using a carboxyl group-containing compound as an emulsifier, an epoxy group and an α, β-ethylenic compound. Reactive microgel prepared by reacting compound (B) having unsaturated double bond (1)
, A compound having an α, β-ethylenically unsaturated double bond
A photosensitive resin composition comprising (2) and a rubber or a thermoplastic elastomer (3). 2. A flexographic original plate comprising the photosensitive resin composition according to claim 1. [0000]