JP2792388B2 - Method for producing hydrophilic copolymer for water development, photosensitive polymer composition for water development using the copolymer, photosensitive flexographic plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a hydrophilic copolymer, a photosensitive polymer composition for water development using the copolymer, and a photosensitive flexographic plate using the composition. is there. More specifically, the present invention provides a method for efficiently producing a copolymer having good hydrophilicity having a main skeleton of a monoolefinic unsaturated monomer unit and a conjugated diene monomer unit optionally introduced. And a photosensitive polymer composition which can be easily developed with a dilute alkaline aqueous solution using the copolymer obtained by this method, and a water-developable photosensitive flexographic plate using the polymer composition. is there.

[0002]

2. Description of the Related Art A photosensitive flexographic printing plate is a relief printing rubber plate comprising a relief formed by using a photosensitive composition molded to a fixed thickness. This is usually
A negative or positive film is brought into close contact with the photosensitive composition and irradiated with active light to form a photosensitive composition layer (hereinafter, referred to as a photosensitive layer).
After exposing selected portions, the unexposed portions are removed to form a relief. In the production of the photosensitive flexographic plate, halogenated hydrocarbons such as 1,1,1-trichloroethane have been conventionally used for removing unexposed portions, but the use of organic solvents has a negative effect on the environment. Had been a problem. In order to solve such a problem, a water-developable photosensitive flexographic plate has recently been proposed. In this flexographic plate, relief is formed by removing unexposed portions with a dilute aqueous solution of sodium hydroxide or the like. In this case, from the solubility of the photosensitive layer in a dilute alkaline aqueous solution and properties such as plate strength required for a printing plate, the flexographic plate has a styrene unit, a butadiene unit, an alkyl acrylate unit, and the like as a main skeleton, Copolymers in which a hydrophilic functional group such as a carboxyl group, a phosphoric acid group, a phosphoric acid ester group, and a sulfonic acid group are introduced are frequently used.
Such a copolymer can be produced by known means such as emulsion polymerization and suspension polymerization. By the way, in the coagulation of a polymer latex such as a styrene-butadiene copolymer and an acrylonitrile-butadiene copolymer obtained by emulsion polymerization using an anionic surfactant,
Using a metal salt such as calcium chloride or aluminum sulfate as a coagulant, polymer latex is allowed to flow down into an aqueous solution of the coagulant, and the whole system is stirred to obtain an aggregate, which is separated and collected as crumb. The method is widely practiced. However, a copolymer having a main skeleton of a styrene unit, a butadiene unit, an alkyl acrylate unit, and the like, into which a hydrophilic functional group such as a carboxyl group, a phosphate group, a phosphate group, or a sulfonic acid group is introduced. When the emulsion polymerization latex obtained using an anionic surfactant is obtained by coagulation with a metal salt, the metal salt reacts with a hydrophilic functional group, so that the hydrophilicity of the copolymer is impaired. I was not spared. Therefore, there has been a serious problem that the copolymer cannot be used for applications requiring hydrophilicity such as a water-developing type photosensitive flexographic plate.

[0003]

SUMMARY OF THE INVENTION Under such circumstances, the present invention provides a hydrophilic composition comprising a monoolefinic unsaturated monomer unit and a conjugated diene monomer unit optionally introduced as a main skeleton. Method for efficiently producing a copolymer having good properties, a photosensitive polymer composition for water development using the copolymer obtained by this method, and a water-developable photosensitive composition using the polymer composition It was also made to provide a sex flexo version.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, it has been found that the gelation of a copolymer having a hydrophilic functional group for water development is carried out by the metal salt. It has been found that this occurs due to ionic bonding with hydrophilic functional groups in the polymer. Further, in order to coagulate such a copolymer having a hydrophilic functional group from an emulsion polymer latex without causing ionic bonds, a specific amine-based compound having a tertiary amine, a quaternary ammonium salt and a polyethylene oxide unit can be used. We focused on the compounds being effective. Then, a monomer mixture of a monoolefinic unsaturated monomer, an unsaturated monomer having a hydrophilic functional group, and a conjugated diene monomer optionally used together, using an anionic surfactant. After obtaining a latex by emulsion polymerization, the latex is coagulated by using at least one selected from tertiary amines, quaternary ammonium salts and specific amine compounds having a polyethylene oxide unit. Gelation in the process is suppressed, and a hydrophilic copolymer can be efficiently obtained, and by using this hydrophilic copolymer, a photopolymerizable unsaturated monomer, and a photosensitizer, a dilute alkaline aqueous solution can be obtained. It has been found that a photosensitive polymer composition that can be easily developed is obtained by using the above method, and that a water-developable photosensitive flexographic printing plate can be obtained by using the polymer composition. The present invention has been completed based on such findings.
That is, the present invention provides a latex obtained by copolymerizing a monomer mixture comprising a monoolefinic unsaturated monomer and an unsaturated monomer having a phosphate ester group under emulsion polymerization conditions, with a tertiary amine. , Quaternary ammonium salts and the general formula

[0005]

Embedded image

(Wherein R ¹ is a hydrocarbon group, R ² and R ³
Are divalent hydrocarbon groups, which may be the same or different, and n and m are each 1 to
A method for producing a hydrophilic copolymer for water development, wherein the method comprises coagulation using at least one selected from compounds represented by the following formula: A) a photosensitive polymer composition for water development comprising the hydrophilic copolymer obtained by the above method, (B) a photopolymerizable unsaturated monomer, and (C) a photosensitizer; An object of the present invention is to provide a photosensitive flexographic printing plate obtained by molding the composition into a sheet.

Hereinafter, the present invention will be described in detail. In the present invention, a monomer mixture comprising a monoolefinic unsaturated monomer, an unsaturated monomer having a phosphate ester group, and optionally a conjugated diene monomer is used as an anionic surfactant. Is used for emulsion polymerization to obtain a copolymer latex. As the monoolefinically unsaturated monomer,
(A) Acrylic esters and methacrylic esters corresponding thereto, and (B) vinyl group-containing compounds other than the monomer (A) and the conjugated diene-based monomer are used. Examples of the monomer (a) include methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, dodecyl acrylate, methoxyethyl acrylate, ethoxyethyl acrylate, cyanoethyl acrylate, and hydroxyethyl acrylate. And acrylates such as hydroxypropyl acrylate and methacrylates corresponding thereto. Examples of the monomer (b) include styrene, acrylonitrile, vinyl chloride, ethylidene norbornene, propenyl norbornene, and dicyclopentadiene. These may be used alone or in combination of two or more.
It does not matter if (b) the monomer and (b) the monomer are used in combination. These monoolefinically unsaturated monomers are usually used in a proportion of 70 to 95% by weight based on the total amount of the raw material monomers when a conjugated diene-based monomer described below is not used. When a rubber-like copolymer is obtained without using a conjugated diene-based monomer described later, the monomer (A) is used as a main component, and the monomer (B) is optionally replaced with the monomer (A). ), (B) It is desirable to use it in a proportion of 20% by weight or less based on the total amount of the monomers. (B) If the amount of the monomer exceeds 20% by weight, the copolymer does not become rubbery. Therefore, the copolymer of the present invention is used for applications requiring rubber elasticity such as a photosensitive flexographic plate. Can not do. On the other hand, as the conjugated diene-based monomer optionally used, for example, 1,3-butadiene,
Examples include isoprene, chloroprene, and 1,3-pentadiene. These may be used alone or in combination of two or more. The conjugated diene-based monomer may be used as a raw material if necessary in order to adjust the rubber elasticity of the copolymer used in the present invention and the water-resistant ink resistance of a photosensitive flexographic plate using the copolymer. It is usually used in a proportion of 90% by weight or less based on the total body weight. In addition, the total amount of the monoolefinic unsaturated monomer and the monoolefinic unsaturated monomer is usually 70 to 95% by weight based on the total amount of the raw material monomers.
The hydrophilic functional group used in the copolymer according to the present invention,
Since the copolymer according to the present invention is used for a photosensitive flexographic printing plate because it is a phosphate ester group, it is preferable from the viewpoint of washability of the photosensitive layer (speed of dissolving in a dilute alkaline aqueous solution) when obtaining the printing plate. Examples of the phosphoric ester group-containing monomer include, for example, a general formula

[0008]

Embedded image

[0009] (R ⁴ in the formula is a hydrogen atom or a methyl group, R ⁵
Is a hydrogen atom, a methyl group, a halomethyl group, etc., p is 1-2
(An integer of 3 and q is 1 or 2) can be used.
Specific examples of the phosphate group-containing unsaturated monomer represented by the general formula [2] include ethylene phosphate (meth) acrylate, trimethylene phosphate (meth) acrylate, propylene phosphate (meth) acrylate, Tetramethylene (meth) acrylate, (bis) ethylene (meth) acrylate, (bis) trimethylene (meth) acrylate, (bis) tetramethylene (meth) acrylate, diethylene glycol (meth) acrylate , Triethylene glycol (meth) acrylate phosphate, polyethylene glycol (meth) acrylate phosphate, (bis) diethylene glycol (meth) acrylate phosphate, (bis) triethylene glycol (meth) acrylate phosphate, (bis) polyethylene phosphate Guri (Meth) acrylate, and these may be used alone or in combination of two or more. In addition, from the viewpoints of washability of the photosensitive layer and processability as a photosensitive composition. It is usually used at a ratio of 5 to 30% by weight based on the total amount of the raw material monomers. The copolymer according to the present invention further optionally,
A polyfunctional vinyl compound containing two or more vinyl bonds in one molecule and having the same reactivity may be introduced. Examples of such compounds include polyacrylates such as ethylene glycol diacrylate, trimethylolpropane triacrylate, and propylene glycol diacrylate, and polyvalent methacrylates corresponding thereto, and further include divinylbenzene and trivinyl. Benzene and the like can be mentioned. These may be used alone or in combination of two or more, and are usually used at a ratio of 0 to 10% by weight based on the total amount of the raw material monomers.

[0010] The emulsion polymerization method used in the present invention comprises:
In an aqueous medium containing an emulsifier and a polymerization initiator,
This is a method of copolymerizing each monomer. As the emulsifier, an anionic surfactant is usually used. Examples thereof include known ones used in emulsion polymerization, such as alkylbenzene sulfonates, alkyl sulfonates, alkyl sulfates, fatty acid metal salts, polyoxyalkyl ether sulfates, and polyoxyethylene carboxylate sulfates. Salt, polyoxyethylene alkyl phenyl ether sulfate, succinic acid dialkyl sulfonate and the like. These may be used alone or in combination of two or more, and the amount of use is selected in the range of 0.1 to 5 parts by weight per 100 parts by weight of the monomer usually used. On the other hand, as the polymerization initiator, a water-soluble inorganic peroxide or a combination of a water-soluble reducing agent and an organic peroxide is used. Examples of the water-soluble inorganic peroxide include potassium persulfate and ammonium persulfate. As a water-soluble reducing agent,
For example, a reducing agent used as a normal water-soluble radical redox polymerization catalyst component, for example, ethylenediaminetetraacetic acid or its sodium salt or potassium salt, or a complex compound thereof with a heavy metal such as iron, copper, or chromium, or sulfinic acid Or its sodium or potassium salt, L-ascorbic acid or its sodium salt, potassium salt, calcium salt, ferrous pyrophosphate, ferrous sulfate, ferrous ammonium sulfate, sodium sulfite, sodium acid sulfite, formaldehyde sulfoxyl Sodium acid, reducing sugars, etc., may be used alone or in combination of two or more. The amount of these reducing agents to be used is usually 0.00 per 100 parts by weight of the monomers used.
It is selected in the range of 01 to 5 parts by weight.

The organic peroxides include, for example, cumene hydroperoxide, p-cymene hydroperoxide, t-butylisopropylbenzene hydroperoxide, diisopropylbenzene hydroperoxide, p-
Hydroperoxides such as menthane hydroperoxide, decalin hydroperoxide, t-amyl hydroperoxide, t-butyl hydroperoxide, isopropyl hydroperoxide and the like can be mentioned. These organic peroxides may be used singly or in combination of two or more.
The amount is selected from the range of 0.001 to 5 parts by weight per 0 parts by weight, and these are used in combination with the above water-soluble reducing agent. In the present invention, adjustment of the molecular weight of the copolymer is performed by t
-Known molecular weight regulators such as dodecyl mercaptan and dialkyl xanthogen disulfide are used. The amount used is usually selected from the range of 0.1 to 5 parts by weight per 100 parts by weight of the total amount of all the monomers. In this emulsion polymerization, higher fatty acids, higher alcohols, inorganic salts, water-soluble polymer compounds and the like may be used in combination in order to promote the action of the emulsifier and polymerization catalyst used. In this emulsion polymerization, the polymerization agent such as each monomer or polymerization initiator may be added in its entirety before the start of the reaction, or may be arbitrarily divided and added after the start of the reaction. The polymerization is usually carried out in an atmosphere of an inert gas such as nitrogen at a temperature in the range of 0 to 80 ° C., but the operating conditions such as temperature and stirring can be arbitrarily changed during the reaction. Further, the polymerization system may be any of a continuous system and a batch system. In this way, a latex in which the copolymer having a particle size of about 0.03 to 0.7 μm is uniformly dispersed is obtained. In the present invention, in order to coagulate the polymer latex thus obtained, a tertiary amine, a quaternary ammonium salt and a compound represented by the general formula

[0012]

Embedded image

(Wherein R ¹ is a hydrocarbon group, R ² and R ³ are each a divalent hydrocarbon group, and they may be the same or different, and n and m each represent 1 to 6
An integer of 0 and k is 0 or 1. At least one amine compound selected from the compounds represented by the formula (1) is used. Examples of the tertiary amine include N, N-dimethylstearylamine, N, N-dimethyllaurylamine,
N, N-dimethylphenylamine, N, N-dimethylnaphthylamine, N, N-diethylstearylamine,
N-diethyllaurylamine, N, N-diethylphenylamine, N, N-diethylnaphthylamine, N-ethyl-N-methylphenylamine, N-ethyl-N-methyllaurylamine, N-ethyl-N-methylnaphthylamine, N-ethyl-N-propylaniline and the like. Examples of the quaternary ammonium salt include a cationic surfactant known in the latex formulation such as lauryltrimethylammonium chloride, stearyltrimethylammonium chloride, dilauryldimethylammonium chloride, and distearyldimethylammonium chloride. On the other hand, in the compound represented by the general formula [1], when k is 0, for example, N-mono (polyoxyethylene) dodecylamine, N
-Mono (polyoxypropylene) dodecylamine, N-
Examples thereof include alkylamine ethylene oxide derivatives such as mono (polyoxyethylene) stearylamine, and alkylamine propylene oxide derivatives. Also, k
Examples of the compound wherein is 1 include alkyl such as N, N-bis (polyoxyethylene) dodecylamine, N, N-bis (polyoxypropylene) dodecylamine and N, N-bis (polyoxyethylene) stearylamine. Examples thereof include an amine ethylene oxide derivative and an alkylamine propylene oxide derivative.

In the present invention, one of these amine compounds may be used alone, or two or more thereof may be used in combination. Upon coagulation, the compound is usually used in an amount of 0.1 to 10
% By weight, and a copolymer latex is added to the aqueous solution. Thereafter, the entire system is stirred at room temperature or under warming until coagulation is complete. Aggregation of latex by the compound is slower than when a metal salt is used,
In general, a high molecular weight polyalkylene oxide having a polyoxyethylene chain has an action of coagulating a substance suspended in water. The polyoxyethylene chain of the amine compound used in the present invention is not so large that a substance suspended alone in water can be aggregated. However, in the present invention,
It is thought that the hydrophilic polymer can be efficiently coagulated from the latex by the above two effects.
After coagulation of the polymer latex in this way, a treatment by a known method such as dehydration and drying is performed to obtain the hydrophilic copolymer according to the present invention. The photosensitive polymer composition using the hydrophilic copolymer obtained by the method of the present invention includes a photosensitive flexographic plate described below, a plate material of a screen printing plate, a photoresist, a paint, a coating agent, an adhesive, a film, It can be preferably used for sheet materials, impregnated materials, and other molded products.

The photosensitive polymer composition for water development of the present invention comprises:
In addition to the hydrophilic copolymer obtained as described above as the component (A), the photopolymerizable unsaturated monomer as the component (B) and the photosensitizer as the component (C) are essential components. It is necessary to contain. Examples of the photopolymerizable unsaturated monomer used as the component (B) include aromatic vinyl compounds such as styrene, α-methylstyrene, m-methylstyrene, and p-methoxystyrene, and acrylonitrile and methacrylonitrile. Unsaturated nitrile compounds, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, etc.
23 alkyl alcohol (meth) acrylates,
(Meth) acrylates of hydroxyalkyl alcohols such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate; (meth) acrylates of alkoxyalkylene glycols such as methoxyethylene glycol and methoxypropylene glycol; maleic acid Monoesters of unsaturated polycarboxylic acids such as monoethyl, monomethyl fumarate, monoethyl itaconate, dimethyl maleate, diethyl maleate, dibutyl maleate, dioctyl maleate,
Diesters such as diethyl fumarate, dibutyl fumarate, dioctyl fumarate, dimethyl itaconate, diethyl itaconate, dibutyl itaconate, dioctyl itaconate, acrylamide, methacrylamide, N, N'-methylenebisacrylamide, N, N ' (Meth) acrylamides such as hexamethylenebisacrylamide, ethylene glycol di (meth) acrylate, polyalkylene glycol (alkylene glycol units 2 to 23)
), Di (meth) acrylate, glycerin, pentaerythritol, trimethylolalkane, tetramethylolalkane (alkanes such as methane, ethane and propane) such as di (meth) acrylate, tri (meth) acrylate, Tetra (meth) acrylate, oligo (meth) acrylates, 2- (meth)
Examples thereof include (meth) acrylates having an acidic functional group such as acryloyloxyethyl succinic acid, 2- (meth) acryloylethyl hexahydrophthalic acid, and 2- (meth) acryloyloxyethyl acid phosphate.

These photopolymerizable unsaturated monomers may be used singly or in combination of two or more. The compounding amount is usually the hydrophilic copolymer of the component (A). 10
5 to 300 parts by weight, preferably 10 to 10 parts by weight
It is selected in the range of 200 parts by weight. When the amount is less than 5 parts by weight, the resulting photosensitive composition is insufficiently cured by active light, so that the mechanical properties of the flexographic plate may be deteriorated. Rubber elasticity and solvent resistance tend to decrease, which is not preferable. Further, in the composition of the present invention, as the photosensitizer used as the component (C), those usually used as a photoreaction initiator, for example, α-diketones such as diacetyl and benzyl, and acyloins such as benzoin and pivaloin , Benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether and the like, and polynuclear quinones such as anthraquinone and 1,4-naphthoquinone. One of these photosensitizers may be used, or two or more thereof may be used in combination.
0.1 to 10 parts by weight, preferably 1 to 100 parts by weight
It is selected in the range of up to 5 parts by weight. If the amount is less than 0.1 part by weight, the resulting photosensitive composition will be insufficiently cured by actinic light, and if it exceeds 10 parts by weight, all of the added photosensitizer will not participate in the reaction, which is uneconomical. In addition, the absorption of the exposed active light tends to decrease the reaction speed to light, which is not preferable.

Components other than those described above can be added to the photosensitive polymer composition of the present invention as needed. Such components include plasticizers, storage stabilizers, elastomeric polymers, and the like. Examples of the plasticizer include hydrocarbon oils such as naphthenic oil and paraffin oil, and a molecular weight of 3
000 or less low molecular weight polystyrene, α-methylstyrene-vinyltoluene copolymer, petroleum resin, polyacrylate, polyester resin, polyterpene resin, polyisoprene and its hydrogenated product, liquid 1,2- and 1,4-polybutadiene and Examples thereof include terminal modified products thereof, hydroxides or carboxylated products thereof, liquid acrylonitrile-butadiene copolymers, carboxylated products thereof, and liquid styrene-butadiene copolymers. These may be used alone or in combination of two or more. These are used for assisting the production and molding of the photosensitive polymer composition, promoting removal of unexposed portions, adjusting hardness of exposed and cured portions, and the like. Depending on these target properties, it is added in the range of 5 to 200 parts by weight per 100 parts by weight of the copolymer of component (A). Examples of the storage stabilizer include hydroquinone, p-methoxyphenol, pt-butylcatechol, hydroxyaromatic compounds such as 2,6-di-t-butyl-p-cresol, and pyrogallol, benzoquinone, p-toluquinone , Quinones such as p-xyloquinone, and amines such as phenyl-α-naphthylamine. One of these storage stabilizers may be used alone, or two or more of them may be used in combination. The amount of the storage stabilizer is usually 0.01 to 2 per 100 parts by weight of the copolymer of the component (A). It is selected in the range of parts by weight.

In the photosensitive polymer composition of the present invention, a known elastomeric polymer may be used, if necessary, within a range not to impair the purpose of the present invention. Examples of such polymers include butadiene polymers, isoprene polymers, chloroprene polymers, styrene-butadiene copolymers, styrene-isoprene copolymers, styrene-chloroprene copolymers, acrylonitrile-butadiene copolymers, Acrylonitrile-isoprene copolymer, acrylonitrile-
Chloroprene copolymer, methyl methacrylate-butadiene copolymer, methyl methacrylate-isoprene copolymer, methyl methacrylate-chloroprene copolymer, methyl acrylate-butadiene copolymer, methyl acrylate-isoprene copolymer, Methyl acrylate-chloroprene copolymer, acrylonitrile-butadiene-styrene copolymer, acrylonitrile-isoprene-styrene copolymer, acrylonitrile-chloroprene-styrene copolymer, epichlorohydrin polymer, epichlorohydrin-ethylene oxide copolymer, epichlorohydrin-
Propylene oxide copolymer, epichlorohydrin rubber, chlorinated polyethylene, vinyl chloride copolymer, vinylidene chloride, chlorinated polypropylene, chlorinated ethylene-propylene rubber, ethyl acrylate-acrylonitrile copolymer, butyl acrylate-acrylonitrile copolymer , Methyl methacrylate-acrylonitrile copolymer,
Butyl acrylate-styrene-acrylonitrile copolymer; Among them, preferred are thermoplastic elastomeric block copolymers such as styrene-butadiene-styrene block copolymer and styrene-isoprene-styrene block copolymer. The copolymer may have any of a linear structure and a radial structure as long as it has at least one ABA unit.

The polymer block A is composed of at least one polymer of a monovinyl aromatic compound such as styrene, α-methylstyrene and ethylstyrene, or a copolymer of a monomer copolymerizable with the compound. And the number average molecular weight is 2
It is a thermoplastic and non-elastomeric polymer block having a glass transition temperature of 000 to 100000 and a glass transition temperature of 25 ° C. or higher. On the other hand, the polymer block B is one or more polymers of conjugated dienes such as 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, and 1,3-pentadiene, or copolymerized with conjugated dienes. Composed of a copolymer with a possible monomer and having a number average molecular weight of 25,000 to 1
It is an elastomeric polymer having a glass transition temperature of 10,000,000 or less. At this time, the ratio of the polymer block A to the polymer block B is in the range where the block copolymer becomes an elastomer, that is, the ratio of the polymer block A to all the blocks in the copolymer is 5 to 50% by weight, preferably Should be in the range of 10 to 40% by weight. If the proportion of the polymer block A exceeds 50% by weight, the block copolymer does not become an elastomer, so that the photosensitive flexographic plate of the present invention cannot have rubber elasticity. Therefore,
The block copolymer cannot be used for the photosensitive flexographic plate of the present invention. On the other hand, if it is less than 5% by weight, the block copolymer becomes rubbery at room temperature, so that the photosensitive flexographic plate of the present invention tends to shrink and lacks dimensional stability. The elastomeric polymer may be used alone or in combination of two or more. When the thermoplastic elastomeric block copolymer is used, the amount used is 5 to 40% by weight, preferably 5 to 40% by weight, based on the total amount of the photosensitive polymer composition, from the viewpoint of the strength and printing durability of the photosensitive flexographic printing plate. Desirably, it is 30% by weight. The photosensitive polymer composition of the present invention can be prepared by various methods. For example, mixing and kneading using a conventional rubber kneading machine such as a kneader or a roll mill, an extruder,
A sheet having a desired thickness can be prepared using a molding machine such as a press or a calender. If desired, the photosensitive composition of the present invention is dissolved in an appropriate solvent such as chloroform, carbon tetrachloride, trichloroethane, methyl ethyl ketone, diethyl ketone, benzene, toluene, tetrahydrofuran, and the mixture is injected into a frame. Then, by evaporating the solvent, a sheet can be prepared. By heating, extruding or calendering this sheet, a sheet having high thickness accuracy can be obtained, and this sheet can be preferably used as a photosensitive flexographic plate.

The photosensitive polymer composition of the present invention has a surface such as polypropylene, polyethylene, polyethylene terephthalate, etc. on its surface in order to prevent contamination or damage of the photosensitive layer during storage or operation after forming into a sheet. A peelable thin transparent film layer can be provided as a base film layer or a protector film layer. As a feature of the photosensitive flexographic printing plate of the present invention, developability with a dilute alkaline aqueous solution can be mentioned. Examples of the diluted alkaline aqueous solution used as the developer include low-concentration aqueous solutions of about 0.1 to 4.0% by weight such as sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonia, and lithium carbonate. In addition, the plate is not limited to such a dilute alkaline aqueous solution, but also a mixed solvent of an alkaline aqueous solution and an alcohol or a ketone, a mixed solvent of a halogenated organic solvent and an alcohol or a ketone, or an aqueous solution of various surfactants. It can be developed. As the surfactant used here, in addition to the aforementioned anionic surfactant and cationic surfactant, amphoteric surfactants such as alkylaminocarboxylates, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, glycerin fatty acid Nonionic surfactants such as esters, pentaerythritol fatty acid esters, and fatty acid alkanolamides. The photosensitive flexographic printing plate of the present invention has a high photosensitivity and requires only a short exposure time, and has a very high solubility in a dilute alkaline aqueous solution, so that it can be developed in about 1 to 10 minutes, and after drying, It has features such as immediate printing, and by using this flexo plate, the plate making process is simpler and the work time is greatly reduced compared to the conventional plate making of rubber plates for flexographic printing. be able to. Furthermore, the photosensitive flexographic plate of the present invention
It goes without saying that printing can be performed with a solvent-type flexo ink, but printing with an aqueous flexo ink that is being used in place of the solvent-type flexo ink from the viewpoint of air pollution is possible because of good water resistance.

[0021]

Next, the present invention will be described in more detail by way of examples, which should not be construed as limiting the present invention. The physical properties of the copolymer and flexographic plate were determined as follows. (1) Mooney viscosity Measured according to JIS K-6300. (2) Workability Mastication was performed with a 6-inch roll (50 ° C.), and the state of the obtained sheet was determined. ：: A smooth sheet is obtained. △: A good sheet is obtained although there are fine irregularities. X: A sheet cannot be obtained. (3) Alkali-soluble composition is pressed to prepare a sheet having a thickness of 3 mm. Then, the unexposed photosensitive layer was dissolved in a 1% by weight aqueous sodium hydroxide solution at 40 ° C. using a nylon brush with a nylon brush to dissolve 1 mm. (4) Hardness The composition was pressed to produce a 3 mm thick sheet,
Using a W / cm ² ultraviolet lamp, exposure treatment was performed for 10 minutes on both sides to obtain a cured product. The hardness of this cured product is measured according to JISK-630.
Measured according to 1. (5) Resolution One side of a sheet of each composition having a thickness of 3.0 mm obtained by the same method as in the above (3) was exposed using a 5 mW / cm ² ultraviolet lamp. Next, a negative film for reproducibility evaluation was brought into close contact with the unexposed surface, and this surface was exposed to the light source for 15 minutes. Remove the negative film,
Unexposed portions were dissolved and removed in a weight% aqueous sodium hydroxide solution using a nylon brush. After that, it was dried at 70 ° C. for 10 minutes.
After re-exposure for one minute, a relief image for evaluating the resolution was created. With respect to this relief image, the reproduction state of the fine line in the convex image portion and the state of engraving of the fine line in the concave image portion were observed with a stereo microscope of 50 times, and each was evaluated according to the following criteria.

Reproducibility of 0.2 mm wide convex fine line The case where the shape of the convex fine line is not distorted, has no thickness, and is reproduced with the same width as the negative is regarded as a “completely reproduced state”, and according to the following criteria. evaluated. ○: Negative reproduction is complete △: Negative reproduction is almost complete ×: Negative reproduction is incomplete 0.7 mm wide concave fine line reproducibility There is no wavy jagged shape of concave fine line The state in which the edge was sharp and the groove of the concave fine line was deeply carved was regarded as “the state completely reproduced”, and evaluated according to the following criteria. ：: The groove of the concave fine line is deep and the edge is carved sharply. △: The groove of the concave fine line is slightly shallow, but there is no problem in practical use. ×: The groove of the concave fine line is shallow. (6) Rubber elasticity BS -903, Pt. A. The measurement was performed using the flat portion of the sample for evaluating a relief image in accordance with the 8-tripso test method. Return angle θ _d after pendulum hits the sample
And calculate the rebound resilience value R

R = [(1−COS θ _d ) / (1−COS θ _o )] × 100. Based on this value, evaluation was performed according to the following criteria. Here, θ _o is the angle of the pendulum before the test, and in this example, 4 _°
5 °. A: Rebound resilience value is 60% or more B: Rebound resilience value is 50% or more and less than 60% C: Rebound resilience value is less than 50% The higher the rebound resilience value, the better the rubber elasticity. Is shown.

Polymerization Example 1 Polymerization was carried out at 50 ° C. in an autoclave having an internal volume of 10 liters using the following monomers and polymerization agents. Weight, polymerization agent weight parts butadiene 50 butyl acrylate 35 ethylene methacrylate 15 sodium dodecylbenzenesulfonate 2 potassium persulfate 0.3 t-dodecylmercaptan 0.4 water 200 In the polymerization, 95% of the total monomers were added. Was reached, a terminator was added, and after cooling with water, an emulsion polymerization emulsion was obtained. Polymerization Example 2 An emulsion polymerization emulsion was obtained in the same manner as in Polymerization Example 1, except that 34.6 parts by weight of ethyl acrylate and 0.4 part by weight of ethylene glycol dimethacrylate were used instead of butyl acrylate. . Polymerization Example 3 An emulsion polymerization emulsion was obtained in the same manner as in Polymerization Example 1, except that butadiene was replaced by 35 parts by weight of methyl acrylate and the amount of butyl acrylate was changed to 50 parts by weight.

Example 1 A coagulant was prepared by dissolving 7 g of N-mono (polyoxyethylene) dodecylamine in 1000 g of water. Next, the emulsion obtained in Polymerization Example 1 was slowly added to the coagulant, and the mixture was stirred for about 2 minutes to coagulate the emulsion. The generated crumb was collected and dried at 70 ° C. for 4 hours. Thus, a hydrophilic copolymer was obtained. This copolymer 10
To 0 g, 20 g of nonaethylene glycol dimethacrylate as a photopolymerizable unsaturated monomer, 20 g of nonaethylene glycol acrylate, 1.5 g of benzoin methyl ether as a photopolymerization initiator and 0.2 g of hydroquinone as a storage stabilizer were added. The photosensitive composition was prepared by kneading at 80 ° C. for 10 minutes with a Brabender having a volume of 200 ml. Next, the composition was sandwiched between polyethylene terephthalate films having a thickness of 0.1 mm, and formed into a thickness of 3.0 mm using a vacuum press. This photosensitive composition maintained its solidity, and there was no problem in handleability. Then, the polyethylene terephthalate film was peeled off, and the optical density of the film was 3.
8 and then exposed for 5 minutes with a commercially available UV exposure machine for photosensitive resin (5 mW / cm ² ,
(320-400 nm) When a developing treatment was performed using a 1% by weight aqueous solution of sodium hydroxide, the unexposed portions were completely dissolved and removed, and a flexographic printing plate faithful to the original was obtained. The plate had rubber elasticity and hardness (Shore A, measured at 20 ° C.) of 55. Further, when the printing plate was subjected to actual flexographic printing, a printed matter faithful to the original image was obtained. Table 1 shows the physical properties of the copolymer, the photosensitive composition and the flexographic printing plate. Examples 2-6, Comparative Examples 1-3 Except for using those shown in Table 1 as a coagulant, a hydrophilic copolymer was obtained in the same manner as in Example 1, and a photosensitive composition was prepared. In addition, a flexographic printing plate was created. The physical properties are shown in Table 1.

[0025]

[Table 1]

(Note) Type of coagulant 1. N-mono (polyoxyethylene) dodecylamine 2. N, N-bis (polyoxyethylene) dodecylamine 3. N, N-bis (polyoxyethylene) octadecylamine 4. Lauryl trimethyl ammonium chloride 5. Stearyl trimethyl ammonium chloride 6. N, N-dimethyllaurylamine Magnesium sulfate 8. Calcium chloride 9. Aluminum Sulfate Examples 7, 8 Comparative Example 4 A hydrophilic copolymer was prepared in the same manner as in Example 1 except that the emulsion obtained in Polymerization Example 2 was used and the coagulant shown in Table 2 was used. Thus, a photosensitive composition was prepared, and a flexographic printing plate was further prepared. The physical properties are shown in Table 2.

[0027]

[Table 2]

(Note) The meaning of the number of the coagulant is the same as the footnote in Table 1. Examples 9 to 14, Comparative Examples 5 to 7 A hydrophilic copolymer was prepared in the same manner as in Example 1 except that the emulsion obtained in Polymerization Example 3 was used, and that the coagulant shown in Table 3 was used. Was obtained, a photosensitive composition was prepared, and a flexographic printing plate was further prepared. Table 3 shows the physical properties.

[0029]

[Table 3]

(Note) The meaning of the number of the coagulant is the same as the footnote in Table 1. As is clear from each table, Examples 1 to 1 were used.
The copolymer obtained by the method 4 of the present invention retains hydrophilicity and can be kneaded with various compounds. Accordingly, by using the copolymer, a photosensitive composition having excellent processability, developability with an aqueous alkali solution, water resistance, and hardness of a cured product can be obtained, which is used for a water-soluble photosensitive flexographic plate. It is suitable as a material. On the other hand, the copolymers of Comparative Examples 1 to 7 obtained using the metal salt were not hydrophilic and could not be kneaded with various compounds, so that the photosensitive composition and the flexographic printing plate were not used. Could not be evaluated.

[0031]

According to the method of the present invention, the monoolefinically unsaturated monomer, the unsaturated monomer having a hydrophilic functional group and the optionally used conjugated diene monomer can be obtained by emulsion polymerization. By coagulating the polymer latex with a specific amine compound, a hydrophilic copolymer suitably used for the photosensitive composition for water development can be efficiently obtained. The photosensitive polymer composition for water development of the present invention containing the hydrophilic copolymer has excellent photosensitivity, processability and developability with an aqueous alkali solution, and the cured product has excellent water resistance and rubber elasticity. It has characteristics and is suitably used as a material for a water-developable photosensitive flexographic plate.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01L 21/027 H01L 21/30 502R (72) Inventor Takao Suzuki 1-2-1 Yoko, Kawasaki-ku, Kawasaki-shi, Kanagawa Japan Zeon stocks (56) References JP-A-3-171139 (JP, A) JP-A-53-10648 (JP, A) JP-A-61-22339 (JP, A) JP-A-60-211451 (JP, A) JP-A-49-87739 (JP, A) JP-A-49-87740 (JP, A) JP-A-51-31789 (JP, A) JP-A-59-155402 (JP, A) JP-A-61-266417 (JP, A) JP-A-6-506261 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03F 7/027 C08F 6/22 G03F 7/00 502 G03F 7/004 501 G03F 7/038 H01L 21/027

Claims (4)

(57) [Claims] 1. A monoolefinically unsaturated monomer and phosphoric acid
A latex obtained by copolymerizing a monomer mixture comprising an unsaturated monomer having an ester group under emulsion polymerization conditions is converted into a tertiary amine, a quaternary ammonium salt and a compound represented by the general formula: (Wherein R ¹ is a hydrocarbon group, R ² and R ³ are each a divalent hydrocarbon group, and they may be the same or different, and n and m are each an integer of 1 to 60;
(k is 0 or 1), and is coagulated using at least one selected from the compounds represented by the following formulas:
A method for producing a hydrophilic copolymer for water development . 2. A monomer mixture comprising a monoolefinic unsaturated monomer, a conjugated diene monomer and an unsaturated monomer having a phosphoric ester group is copolymerized under emulsion polymerization conditions. The latex is made up of a tertiary amine, a quaternary ammonium salt and a compound of the general formula (Wherein R ¹ is a hydrocarbon group, R ² and R ³ are each a divalent hydrocarbon group, and they may be the same or different, and n and m are each an integer of 1 to 60;
(k is 0 or 1), and is coagulated using at least one selected from the compounds represented by the following formulas:
A method for producing a hydrophilic copolymer for water development . 3. The method according to claim 1, wherein (A) is selected from the group consisting of:
Copolymer obtained by the method, (B) photopolymerizable unsaturated
Photosensitizer for water development comprising a monomer and (C) a photosensitizer
Polymer composition. 4. The photosensitive polymer composition for water development according to claim 3,
A photosensitive flexographic plate obtained by molding into a sheet.