WO1994023341A1

WO1994023341A1 - Reactive microgel, photosensitive resin composition containing the same, and flexographic plate material

Info

Publication number: WO1994023341A1
Application number: PCT/JP1993/000425
Authority: WO
Inventors: Tatsuya Hasegawa; Nobumori Kanno
Original assignee: Toyo Ink Manufacturing Co., Ltd.
Priority date: 1993-03-31
Filing date: 1993-03-31
Publication date: 1994-10-13

Abstract

A reactive microgel prepared by the reaction of fine microgel particles (A) prepared by the emulsion polymerization of an α,β-ethylenically unsaturated compound in the presence of a carboxylated compound as the emulsifying agent with an epoxy compound (B) having at least one α,β-ethylenically unsaturated double bond; a photosensitive resin composition comprising the microgel, an α,β-ethylenically unsaturated compound and a rubber or a thermoplastic elastomer; and a flexographic plate material made from the composition and developable with water alone.

Description

Description Reactive microgel, photosensitive resin composition containing the microgel, and flexographic printing plate material

The present invention relates to a reactive microgel having an <<, -ethylenically unsaturated double bond (

1) a photosensitive resin composition comprising the reactive microgel (1), a compound having a / 9 monoethylenically unsaturated double bond (2) and a rubber or a thermoplastic elastomer (3); Flexographic printing plate material using the reactive resin composition.

Background art

Microgels are gelled or crosslinked polymer particles, usually 0.001 to 10 m in diameter, generally less than l jum, approximately the same size as colloids, often synthesized by emulsion polymerization Is done. This microgel is a new polymer material that has attracted attention in recent years. However, those with no reactive groups on the surface of the microgel serve only as a filler, and were used only for the purpose of improving the strength of the material.

Reactive microgels having reactive groups on the surface of the microgel were published in 1975 by Funke of Doi. The microgels synthesized by Funke are emulsified and polymerized under very mild conditions with monomers having two or more a, β-ethylenic unsaturated double bonds, and remain unreacted on the surface. The 3-ethylenically unsaturated double bond was modified with other reagents and converted into various reactive groups. For example, it is a method of converting to an epoxy group using peroxide, a hydroxyl group using borane, a halogen group using hydrogen halide, and a carboxyl group using ozone. However, the reaction to convert to various reactive groups does not take place in a system where water is present, so the microgels must be separated from the aqueous dispersion, purified, and dispersed again in the organic solvent, resulting in cost and cost. There was a limitation in using it as an industrial material from the point of view of labor and the like. Prayer makeup Yamazaki et al. Proposed a method of synthesizing a reactive microgel in one step by emulsion-copolymerizing a polyfunctional monomer having a hydroxyl group, an epoxy group, and an <<, ethylenically unsaturated double bond group (Yamazaki, Hattori, Surface 1987, 25, 86). However, the functional groups that can be introduced by this method are very limited, and in particular, functional groups having a / 3-ethylenically unsaturated double bond are attacked by radicals during emulsion polymerization and react. The synthesis of reactive microgels with, / 3-ethylenically unsaturated double bonds was difficult.

On the other hand, in recent years, flexographic printing has come into the spotlight with the modernization of packaging. However, conventional methods for manufacturing flexographic plates include (a) metal plate making, (mouth) molding, and (c) raw rubber. It requires at least three vulcanization steps, requires sophisticated technology and requires a long time, and the cost cannot be avoided. A flexible resin plate was developed, and it became possible to easily make a flexographic plate.However, since these plates are based on a gen-based rubber such as polybutadiene, trichlorene and perchlorene are used as developers when developing. However, recently, halogen-based solvents have been regulated due to environmental problems and toxicity of the halogen-based solvents to the human body. There in the direction.

Therefore, the emergence of a flexographic plate that can be developed with water that is nontoxic to the human body and that has resistance to water-based ink used in flexographic printing has been awaited. However, it has been difficult for conventional technologies to satisfy the conflicting requirements of water developability, water resistance and alcohol resistance.

Thus, as a result of intensive studies, the present inventors have discovered an addition reaction that occurs in water. By using this addition reaction, it was found that a reactive microgel having a quantitatively added <<, / 3-ethylenically unsaturated double bond can be produced without isolating the microgel from the aqueous dispersion. The present invention has been achieved. Further, as a result of studying the application of the reactive microgel to a water-developing type flexographic plate, the reactive microgel (1), (2) and (3) a compound having a monoethylenically unsaturated double bond and a rubber or Thermoplastic Unlike a conventional flexographic printing plate, the original plate for flexographic printing using a photosensitive resin composition containing a lastmer (3) can be developed with water alone after exposing the image area, and has water resistance, alcohol resistance, etc. It was found to be excellent and rich in rubber elasticity. Disclosure of the invention

The present invention provides a microgel fine particle (A) in which a compound having a, 2,3-ethylenically unsaturated double bond is synthesized by emulsion polymerization using a carboxyl group-containing compound as an emulsifier, a carboxy group and at least one α, 3 —Provide a reactive microgel (1) obtained by reacting with a compound having an ethylenically unsaturated double bond (II).

Further, the present invention provides a photosensitive resin composition comprising the reactive microgel (1), a, a compound having a 3-ethylenically unsaturated double bond (2) and a rubber or a mature plastic elastomer (3). provide. The present invention further provides a flexographic printing plate comprising the photosensitive resin composition.

Hereinafter, the reactive microgel (1) of the present invention will be described in detail.

Examples of monofunctional compounds having an ethylenically unsaturated double bond include the following (a), (b) and (c).

(a) (meth) acrylate compounds: (meth) methyl acrylate, (meth) acrylic acid ethyl, (meth) propyl acrylate, (meth) isopropyl acrylate, (meth) butyl acrylate, (meth) -C and _B alkyl esters of (meth) acrylic acid such as hexyl acrylate, octyl (meth) acrylate, and lauryl (meth) acrylate: C of (meth) acrylic acid such as acryl (meth) acrylate

2 -C _{2 0} alkenyl esters: hydroxyl E chill (meth> Akurireto, hydrin port Kishiruechiru (meth) Akurireto, hydroxypropionic Building (meth) Akurire bets, hydroxypropyl (meth) Akurireto etc. (meth) C ₂ ~ acrylic acid c ₂ hydroxyl alkyl ester. § Lil O hexyl E chill (meth) Akurire bets, etc. (meth) C ₃ -C acrylic acid, 9 alkenyl O hexyl esters:

(Meth) acrylic acid, etc., and A urethane compound obtained by modifying a glycol with diisocyanate and reacting it with an acryl monomer having one OH such as 2-hydroxyacrylate or 2-hydroxymethacrylate. Examples of the glycols include ethylene glycol, propylene glycol, butane glycol, pentyl glycol, polyethylene glycol, propylene glycol, polybutyrolactone polyol, polyester diol, acryl diol, butadiene glycol, and isopropyl glycol.

(b) Vinyl aromatic compounds: styrene, α-methylstyrene, vinyltoluene, chlorostyrene, etc. are exemplified.

(c) Others: acrylonitrile, methacrylonitrile, methyl isopropenyl ketone: vinyl acetate, vinyl propionate and the like.

Next, polyfunctional compounds having two or more functional groups for three-dimensionally cross-linking the inside of the microgel particles include trimethylolpropane tri (meth) acrylate, and glycol di (meth) acrylate. Examples thereof include (meth) acrylate compounds such as di (meth) acrylates of esters and polyols and di (meth) acrylates of polyesters.

Further, a urethane compound obtained by modifying a glycol with diisocyanate to form isosinate groups at both molecular ends and reacting the resulting isocyanate group with an acrylyl monomer having one molecule can be cited. Examples of the glycols include ethylene glycol, propylene glycol, butane glycol, pentyldaricol, polyethylene glycol, propylene glycol, polyprolactone polyol, polyester polyol, acrylic polyol, butadiene glycol, isoprenglycol, and the like. .

Furthermore, a polybutadiene polyisoprene having an epoxy group, an anhydride group or the like at a terminal or a side chain has a functional group which reacts with these groups and a <<, 3-ethylenically unsaturated double bond. Excess diisocyanate groups are reacted with polygens obtained by reacting compounds and hydroxyl groups at the terminals and side chains, and the remaining isocyanates are reacted. Examples of the borigens obtained by reacting a cyanate group with a hydroxyalkylesterpolyaryl alcohol. Examples of the compound having a β-ethylenically unsaturated double bond include C _{2 to} C ₂ such as hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate. Examples thereof include hydroxyalkyl esters, aryl alcohols and aryl amines.

These compounds are appropriately selected depending on the desired physical properties, and may be used alone or in combination of two or more.

However, when a monofunctional compound is used, three-dimensional crosslinking is not performed by itself. Therefore, it is necessary to use a polyfunctional reactive emulsifier in combination with a polyfunctional compound or as an emulsifier described later.

When the obtained reactive microgel is used for a flexographic printing plate, it is preferable to use a urethane compound or a borigen.

The carboxyl group-containing compound has an effect as an emulsifier, and is usually a carboxylate in which the carboxyl group in the carboxyl group-containing compound is neutralized with an alkali metal, an amine, ammonium or the like. .

Among such emulsifiers, examples of the low-molecular emulsifier include a reaction product of a reactive monomer with an alkali metal, an amine, ammonia, or the like. Examples of the reactive monomer include saturated fatty acids such as caprylic acid, lauric acid and stearic acid, acrylic acid, methacrylic acid, maleic acid, itaconic acid and the like.

Examples of the polymer emulsifier include a homopolymer of a reaction product of a reactive monomer having a carboxyl group and an alkali metal, an amine, ammonia, or the like. Examples of the reactive monomer having a carboxyl group include acrylic acid, methacrylic acid, maleic acid, and itaconic acid. Alternatively, a product obtained by copolymerizing a reaction product of the above-mentioned reactive monomer having a carboxyl group with an alkali metal, an amine, ammonium or the like and one or more other reactive monomers can also be selected. Other reactive monomers include (meth) methyl acrylate, (meth) ethyl acrylate, (meth) propyl acrylate, (meth) butyl acrylate, (meth) acrylic To acid hexyl, etc. (meth) Contact to c _{1 8} alkyl esters of acrylic acid: glycidyl

(Meth) acrylates: of (meth) acrylic acid such as aryl (meth) acrylate

C ₂ -C ₈ alkenyl ester hydroxy E chill (meth) Akurireto etc. (meth) c ₂ to c ₈ hydroxyalkyl esters of acrylic acid: Ariruokishirue Chiruakurireto etc. (meth) C ₃ ~0 _{1 8} Aruke acrylic acid Examples include vinyl monomers such as niloxyl alkyl esters.

When a polymer emulsifier is used, the reaction between a reactive monomer having a carboxyl group and an alkali metal, an amine, or ammonia, as described above, is performed by homopolymerization or copolymerization with another vinyl monomer, as described above. And may be carried out after homopolymerization or copolymerization with another vinyl monomer.

Alkali metal used to neutralize these emulsifiers includes sodium hydroxide, potassium hydroxide, calcium hydroxide and the like, and amines include monoethanolamine, diethanolamine, and triethanolamine. Ethanolamine, triethylamine, triptylamine, dimethyldodecylamine and the like.

These emulsifiers can be used as they are, or by reacting a part of the carboxyl group with an ethoxy group such as glycidyl (meth) acrylate, to form a reactive emulsifier into which an, / 3-ethylenically unsaturated double bond is introduced. Can also be used as Since the above-mentioned polymer emulsifier can control the degree of water solubility, it is a preferable emulsifier in applications requiring water resistance. For the purpose of assisting emulsification, an anionic or nonionic low molecular surfactant may be used in combination with the above-mentioned polymeric emulsifier within a range not to impair the physical properties such as water resistance.

Examples of nonionic surfactants include polyoxyethylene alkyl ethers such as boroxyethylene lauryl ether, boroxyethylene stearyl ether, and polyoxyethylene cetyl ether: polyoxyethylene octylphenyl ether: polyoxyethylene Alkyl allyl ether: boroxyethylene derivative: oxyethylene / oxypropylene block copolymer: sorbitan such as sorbitan monolaurate, sorbitan monostearate, sorbitan trioleate Fatty acid ester: glycerin fatty acid ester: polyoxyethylene fatty acid ester and the like.

Examples of the anionic surfactant include fatty acid salts such as sodium stearate and potassium oleate: alkyl sulfates such as sodium lauryl sulfate, triethanolamine lauryl sulfate, and ammonium lauryl sulfate: alkylbenzene sulfonate: alkyl Naphthalene sulfonate: Alkyl sulfosuccinate: Alkyl diphenyl ether disulfonate: Alkyl phosphate: Polyoxyethylene alkyl sulfate.

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 a 3-ethylenically unsaturated double bond. The emulsion polymerization temperature is 50 to 95, preferably 65 to 95%. it is a ~80 ^e C.

At the time of emulsion polymerization, the solid content of the compound having an <<, β-technylene 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 formed 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 a carboxyl group on the surface. The reactive microgel of the present invention is obtained by reacting a carboxyl group on the surface with an epoxy group and an ethoxy group of a compound (Β) having at least an α, / 3-ethylenically unsaturated double bond. It is.

Compounds (Β) include α, β-ethylenically unsaturated double bonds such as glycidyl (meth) acrylate, Ν-glycidylacrylamide, glycidylaryl ether, 1,2-epoxy-5-hexene, etc. Epoxy compounds. These compounds (Β) are appropriately selected according to the desired physical properties, and can be used alone or in combination of two or more thereof, and can be used in an amount of 1 to 100 mol% based on the carboxyl group on the microgel surface. The reaction can be performed at any ratio.

This reaction is to mix Ebokishi compound microgel aqueous dispersion, 30 to 90 ^e C, preferably terminated by simply撐拌least 2 hours at a temperature of 60 to 80. in this way, The reactive microgel of the present invention has an advantage that it can be produced even in an aqueous dispersion.

The reactive microgel of the present invention can be used as an aqueous dispersion or as an aqueous dispersion of an organic solvent in which water is partially or entirely removed by azeotropic distillation by mixing it with a solvent such as aromatic hydrocarbons, alcohols and ketones. Provided as a liquid. When it is desired to use the composition in a dry state, a usual drying method, preferably a method of coagulating the aqueous dispersion, washing and drying the coagulated material to obtain a fine powder, vacuum drying, freeze drying, or spray drying is used. Obtainable.

1 to 200 parts by weight of compound (2) having an ethylenically unsaturated double bond and 1 to 200 parts by weight of rubber or thermoplastic elastomer (3) per 100 parts by weight of reactive microgel (1) The photosensitive resin composition of the present invention can be obtained by mixing in the range of (parts in solid content). More preferably, the compound having a,, / 3-ethylenically unsaturated double bond is 1 to 100 parts by weight, based on 100 parts by weight of the reactive microgel, and 100 parts by weight of the rubber or the thermoplastic elastomer (3). Mix in the range of 1 to 100 parts by weight.

«. As the compound (2) having a 3-ethylenically unsaturated double bond, one or more of monomers, oligomers, and prepolymers can be used. For example, the same material as the material of the core of the reactive microgel described above, that is, the compound having an α, monoethylenically unsaturated double bond, which is the material of the microgel fine particles, can be mentioned. Preferred are oligomers and prepolymers. Among them, compounds having flexibility, flexibility, toughness, rubber elasticity, and the like in a state after crosslinking and curing are preferable. For example, <<, a urethane compound having a β-ethylenically unsaturated double bond, a polygen having a ,, 9-ethylenically unsaturated double bond at a terminal or a side chain, that is, urethane acrylate, polybutadiene acrylate, etc. Is mentioned.

Rubber or thermoplastic elastomer (3) added to supplement rubber elasticity include butadiene rubber, styrene-butadiene rubber, isoprene rubber, styrene-isoprene rubber, neoprene rubber, acrylonitrile-butadiene rubber, chlorophenylene rubber, acrylic rubber, Urethane rubber, silicone rubber, raw rubber, urethane elastomer And one or more of these rubbers or thermoplastic elastomers can be arbitrarily selected and used.

When a powder of reactive microgel is used, these materials are mixed using a kneader, two-roll, extruder, or the like. When an aqueous dispersion of a reactive microgel is used, it may be mixed with the above-mentioned aqueous dispersion of styrene-butadiene rubber, isoprene rubber, urethane rubber or the like.

In the photosensitive resin composition of the present invention, a thermal polymerization inhibitor, a photoinitiator, an antioxidant may be mixed as necessary, and a colorant, an extender, a lubricant, an antifoaming agent, etc. It may be added to the extent that the properties are not impaired.

When the photosensitive resin composition of the present invention is used as a flexographic printing plate material, it is formed into a sheet having a thickness of about 1 to 8 mm using a mature resin, an extrusion molding machine, or the like. A base film and a cover film are provided on both sides. Then, the negative film of the document is brought into close contact with the sheet, and the resin in the sheet is cured by irradiating it with ultraviolet light for a certain time. By peeling the negative film and washing the uncured portion of the sheet with a brush in water, a flexographic printing plate having sufficient rubber elasticity can be obtained. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in more detail with reference to Examples. In the examples, “parts” and “%” indicate “parts by weight” and “% by weight”, respectively.

(Example 1)

(a) Synthesis of non-reactive polymer 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 in a nitrogen atmosphere with stirring in a 1-liter reaction vessel. 5% § (referred to hereinafter as AAPD) zone bis amidinopropane dihydrochloride aqueous solution were added 16 parts of 2 hours, then added 5% AAPD solution 4 parts, 80 added after the end of the reaction mixture ^e C For 4 hours to complete the polymerization to obtain a non-reactive polymer emulsifier. (b) Synthesis of reactive microgel

Nitrogen, 95 parts of styrene, 5 parts of divinylbenzene, 250 parts of non-reactive polymer emulsifier synthesized with (a) (adjusted to 20% solids), and 250 parts of deionized water in a 1 liter reactor with stirring Heated to 80 in atmosphere. Add 16 parts of 5% AAPD aqueous solution and hold for 2 hours, then add 4 parts of 5% AAPD aqueous solution, and after completion of addition, keep the reaction mixture at 80C for 4 hours to complete polymerization and complete non-reactive microgel. An aqueous dispersion was obtained. The measurement result of the microgel particle diameter in this dispersion by the light scattering method was about 80 nm. After leaving the obtained non-reactive microgel aqueous dispersion overnight, 17.8 parts of glycidyl methacrylate was added, and the mixture was heated to TC in an air atmosphere and stirred for 4 hours to form a microgel surface. First, a reactive microgel ^ dispersion with a β-ethylenically unsaturated double bond was obtained.

(Example 2)

(c) Synthesis of reactive polymer emulsifier

100 parts of the non-reactive polymer emulsifier obtained in Example 1 (a) and 14,6 parts of glycidyl methacrylate (hereinafter referred to as GMA) were heated to 80C in a 1-liter reaction vessel while stirring. Stirring was continued for an hour to obtain a reactive polymer emulsifier.

(d) Synthesis of reactive microgel

100 parts of modified diatalylate of boributadiene (trade name: R-45ACR-LC, manufactured by Idemitsu Petrochemical Co., Ltd.), 10 parts of nonionic surfactant (trade name: Marugen 810, manufactured by Kao Corporation), (c) synthesized reactive polymer emulsifier 100 parts (adjust the solid 20%), under stirring 290 parts of deionized water in a 1 liter reaction vessel was heated to 80 ^e C in a nitrogen atmosphere. The 5% AAPD aqueous solution was added 16 parts of 2 hours, then added 5% AAPD aqueous solution 4 parts, the end of the addition after the reaction mixture was complete the polymerization was maintained for 4 hours to 80 ^e C, non-reactive An aqueous microgel dispersion was obtained. The measurement result of the microgel particle diameter in this dispersion by the light scattering method was about 200 mn.

After leaving the obtained non-reactive aqueous gel dispersion of mic mouth gel overnight, add 7.1 parts of glycidyl methacrylate, heat to 80 ° C in an air atmosphere, and stir for 4 hours. As a result, a reactive microgel aqueous dispersion having <<.; 3-ethylenically unsaturated double bond on the surface of the microgel was obtained.

(Comparative Example 1)

Comparative Example 1 is a non-reactive microgel aqueous dispersion containing no glycidyl methacrylate in Example 1.

(Comparative Example 2)

The non-reactive microgel aqueous dispersion in Example 2 to which glycidyl methacrylate was not added is referred to as Comparative Example 2.

(Evaluation of physical properties of reactive microphone gel)

The evaluation of the reactive microgel as a means of improving the physical properties of the acrylic resin, that is, the evaluation of the characteristics of the reactive microgel as a photosensitive resin was performed as follows.

The reactive microgel aqueous dispersion and the non-reactive microgel aqueous dispersion of Examples 1-2 and Comparative Examples 1-2 were respectively 50% (solid content ratio) with respect to the aqueous solution of the photosensitive acryl resin and the aqueous solution of the non-photosensitive acryl resin. And 5% of the total solid content of Darocur 2959 (trade name, manufactured by Merck) as a photopolymerization initiator was added as a non-photosensitive acryl resin. A reactive polymer emulsifier synthesized in Example 2 was used as the photosensitive acrylic resin.

Using this mixed solution, a film having a thickness of about 200 m was formed by a casting method, and then cured by irradiating 200 mJ of ultraviolet light.

The film after the ultraviolet irradiation was cut into a strip having a width of 10 mm, and the tensile strength of the film was measured using a tensile tester under the conditions of a tensile speed of 3θ / «ηηη. Table 1 shows the results. Two

Sample tensile strength

Microgel acrylic resin (kg / cm ² ) Example 1 Photosensitive acrylic resin 7 8 9

Non-photosensitive acrylic resin 2

2 Photosensitive acryl resin 9 2 5

2 Non-photosensitive acrylic resin 3 8 6

Comparative Example 1 Photosensitive acrylic resin 3 2

Non-photosensitive acrylic resin 9 2

2 Photosensitive acrylic resin 4 4 7

2 Non-photosensitive acrylic resin 1 5 0

(Example 3)

(e) Synthesis of urethane methacrylate

100 parts of a polyester diol having a molecular weight of 1000 obtained by the polycondensation reaction of butanediol and adipic acid, 100 parts of diphenylmethanediisocyanate, and 0.1 part of tin octanoate were mixed and mixed in a flask. After reacting at 30 ° C for 30 minutes and then at 80 ° C for 4 hours, add 26 parts of 2-hydroxyethyl methacrylate and further add 80 parts. The mixture was reacted with C for 3 hours to obtain urethane methacrylate.

The reactive microgel aqueous dispersion synthesized in Example 1 was placed in a vat and dried in an oven at 50 for 1 day. 60 parts of microgel powder obtained, and the urethane methacrylate synthesized in (e) 20 20 parts, Bolibutadiene rubber (trade name: JSR BR02LL. Manufactured by Nippon Synthetic Rubber Co., Ltd.) and 5 parts of Darocur-1959 (trade name, manufactured by Merck) are added and dispersed by two rolls, and the microgel mixture is dispersed. obtained. the thus microgel mixture obtained at 50 by a pressing machine, and a uniform film having a thickness of about 3 Jour under conditions of lOOKg / cm ²

(Example 4) A uniform film having a thickness of about 3 mtn was obtained in the same manner as in Example 3, except that the aqueous dispersion liquid of the gel with a reactive microphone mouth was prepared in Example 2.

(Example 5)

The same operation as in Example 3 was performed except that polybutadiene diacrylate (trade name: H-1000-80, manufactured by Nippon Oil Co., Ltd.) was used instead of urethane methacrylate (e) to obtain a uniform thickness of about 3. A good film was obtained.

(Example 6)

A uniform film having a thickness of about 3 was obtained in the same manner as in Example 4, except that M-1000-80 was used instead of urethane methacrylate (e).

(Example 7)

A uniform film having a thickness of about 3 mm was obtained in the same manner as in Example 3, except that styrene 'isoprene.Styrene block copolymer (trade name: Clayton D1320X, manufactured by Shell Chemical Co., Ltd.) was used instead of the polybutadiene rubber. I got

(Example 8)

A uniform film having a thickness of about 3 m «n was obtained in the same manner as in Example 4, except that Clayton D1320X was used instead of polybutadiene.

(Comparative Example 3)

The same procedure as in Example 3 was carried out except that the aqueous non-reactive microgel dispersion synthesized in Comparative Example 1 was used instead of the aqueous reactive microgel dispersion synthesized in Example 1, and the thickness was reduced. Was obtained.

(Comparative Example 4)

The thickness was operated in the same manner as in Example 3 except that the non-reactive microgel aqueous dispersion synthesized in Comparative Example 2 was used instead of the reactive microphone-mouth gel aqueous dispersion synthesized in Example 1. A uniform film of about 3 mm was obtained.

(Comparative Example 5)

A uniform film having a thickness of about 3 was obtained in the same manner as in Comparative Example 4, except that M-1000-80 was used instead of urethane methacrylate (e). (Comparative Example 6)

A uniform film having a thickness of about 3 mm was obtained in the same manner as in Comparative Example 4, except that Clayton D1320X was used instead of polybutadiene.

(Evaluation of physical properties of flexographic printing plates)

The films obtained in Examples 3 to 8 and Comparative Examples 3 to 5 were irradiated with ultraviolet rays of 4000 mJ / _cm ² to obtain cured films. The cured film has a tensile strength, elongation, rubber hardness, water resistance, and IPA (isopropyl alcohol) resistance of 25. Table 2 shows the results measured in C.

Tensile strength: Cut to a width of 10 mm, and measured with a tensile tester at a tensile speed of 50 _mm / min in elongation.

Rubber hardness: Measured according to JIS-K6301.

Water resistance: Each was immersed in ion-exchanged water and IPA for 24 hours, and its swelling was evaluated by measuring the IPA resistance rate.

Swelling rate = ((weight after immersion for 24 hours, weight before immersion) -1) X100 Resolution: Overlap the mask film with various line width patterns on the film and irradiate with the above ultraviolet rays, and develop with water. The thinnest line width obtained by using the resolution was defined as the resolution.

Table 2 Tensile strength Elongation Rubber hardness Water, J β expansion κ / moisture ιΙ¾ rate -τ ^ ΙΡΑ expansion rate

(kg / cm ² ) (Ϊ) (%) (%) ι xm) Example 3 38 150 70 3 11 50 Example 4 35 330 50 3 12 50 Example 5 33 160 68 4 13 5 o Example 6 36 330 51 3 11 50 Example 7 37 140 69 4 12 50 Example 8 35 340 48 3 12 50 Comparative example 3 22 140 68 4 14 100 Comparative example 4 20 300 69 4 13 100 Comparative example 5 24 310 51 3 15 100 Comparative Example 6 23 310 52 3 13 100 Industrial applicability

According to the present invention, a reactive microgel having a hydrophilic group and a double bond efficiently and quantitatively on its surface is provided. Further, according to the present invention, there is provided a photosensitive resin composition comprising the reactive microgel, a compound having an ethylenically unsaturated double bond, and a rubber or a thermoplastic elastomer. According to the present invention, there is further provided a flexographic printing plate material which is excellent in rupture strength, rupture elongation, rubber hardness and water resistance by using the photosensitive resin composition, and can develop an uncured portion with water alone. Is done.

Claims

The scope of the claims

1. Microgel fine particles (A) synthesized by emulsion polymerization of a compound having an a, / 9-ethylenically unsaturated double bond using a carboxyl group-containing compound as an emulsifier, and an epoxy group and at least one a, β-ethylene A reactive microgel characterized by reacting with a compound having an unsaturated double bond (Β).

2. The method according to claim 1, wherein a nonionic surfactant or an anionic surfactant is used in combination with a carboxyl group-containing compound as an emulsifier when the microgel fine particles (Α) are emulsion-polymerized. Reactive microgel.

3. A carboxyl group-containing compound and a surfactant as an emulsifier are added in an amount of 0.1 to 50% by weight based on a compound having an α, β monoethylenically unsaturated double bond. The reactive microgel according to claim 1, wherein

4. It comprises the reactive microgel (1) according to claim 1, a compound having an ethylenically unsaturated double bond (2), and a rubber or a thermoplastic elastomer (3). Photosensitive resin composition.

5. Reactive microgel (1) 100 parts by weight, <<, compound having a / 3-ethylenically unsaturated double bond (2) 1 to 200 parts by weight, rubber or thermoplastic elastomer (3) 5. The photosensitive resin composition according to claim 4, comprising 1 to 200 parts by weight.

6. A plate for flexographic printing, characterized by using the photosensitive resin composition according to claim 4.