JPH10228101A - Photosensitive resin composition for printing plate and photosensitive resin plate material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photosensitive resin compsn. showing high image reproducibility, good water-developing property and enough adaptability for a water-based ink by incorporating a compd. having hydroxyl groups, amide bonds and hydrocarbon groups in the molecule, polymerizable unsatd. groups and a photopolymn. initiator. SOLUTION: This resin compsn. contains (A) a compd. having three or more hydroxyl groups, amide bonds and hydrocarbon groups having >6 carbon atoms in the molecule, (B) polymerizable unsatd. groups and (C) a photopolymn. initiator. The component (A) is a N-alkylglucon amide compd. expressed by formula: R-HNCO(CHOH)4 CH2 OH. In the formula, R is an alkyl group of 6 to 24 carbon atoms. The N-alkylglucon amide compd. contains 0.01 to 20wt.% therein. The compsn. preferably contains a resin, and especially a hydrophilic polymer as an essential component. Further, in order to use the resin for a flexographic printing plate, the compsn. preferably contains a rubber component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive resin composition for a printing plate, and more particularly to a photosensitive resin composition for a printing plate suitably used for flexographic printing with improved water developability. It is.

[0002]

2. Description of the Related Art A photosensitive resin composition in which an elastomer such as chlorinated rubber, styrene-butadiene block copolymer, polyurethane or the like is used as a carrier resin component and an ethylenically unsaturated compound and a photopolymerization initiator are disposed therein is used as a photosensitive resin composition. Utilizing its characteristics, it is useful as a flexographic printing plate material, and many proposals have been made, for example, in U.S. Pat. Nos. 2,948,611 and 3,024,180 and JP-B-51-43374.

Such a photosensitive resin solid printing plate requires halogenated hydrocarbon development, and has problems such as health hazards and environmental pollution. Therefore, a photosensitive resin solid flexographic printing plate which can be developed with water. It is desired to develop a material. For example, Japanese Patent Publication No. 62-42259, Japanese Patent Application Laid-Open No. 61-22339, Japanese Patent Application Laid-Open No. 63-186232, etc. provide a water-developable photosensitive resin solid flexographic printing plate material. There have been proposals for photosensitive resin compositions.

[0004] However, it is difficult to satisfy all of the raw plate strength and water developability of the printing plate material, the flexibility as a flexographic printing plate, and the compatibility with a water-based ink which is a main ink of flexographic printing. No practically satisfactory one has been obtained. In particular, in the developing step, a photosensitive resin solid flexographic printing plate material having practical developability with substantially only neutral water has not been obtained.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks of the prior art, and has as its object to provide high image reproducibility and good water developability. Another object of the present invention is to provide a photosensitive resin composition suitable for a printing plate satisfying compatibility with aqueous ink.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is as follows.
"For a printing plate containing (A) a compound having 3 or more hydroxyl groups, an amide bond and a hydrocarbon group having 6 or more carbon atoms in a molecule, (B) a polymerizable unsaturated compound, and (C) a photopolymerization initiator. The photosensitive resin composition for a printing plate, wherein the component (A) is an N-alkylgluconamide compound represented by the general formula (I).

## STR2 ## R-HNCO (CHOH) ₄ CH ₂ OH (wherein R is an alkyl group having 6 to 24 carbon atoms).
The photosensitive resin composition for a printing plate described above, which is contained in an amount of 20 to 20% by weight. "The photosensitive resin composition for a printing plate according to any one of the above, further comprising a base resin.",
"The printing plate photosensitive resin composition wherein the base resin contains a hydrophilic polymer and rubber.""The printing plate wherein the vulcanized rubber and unvulcanized rubber are dispersed in the hydrophilic polymer. Resin composition for use in printing plates, wherein the photosensitive resin composition according to any one of the above-mentioned is applied on a support utilizing the properties thereof. . ".

[0007]

Embodiments of the present invention will be described below. In the present invention, “weight” means “mass”.

[0008] The composition of the present invention preferably contains a base resin. In particular, it is preferable to use a hydrophilic polymer as an essential component. For use as a flexographic printing plate, it is preferable to further contain a rubber component.

The hydrophilic polymer of the present invention refers to a polymer having the property of dissolving and / or dispersing in water. For example, a polymer formed into a film is immersed in water at 23 ° C., and after 24 hours, the polymer is dissolved. The film loses or disintegrates by 50% by weight or more by eluting the whole surface or partially, or by swelling and dispersion of the polymer and dispersion in water.

Examples of such hydrophilic polymers include polymers soluble in alcohol and / or water, and polyamides, partially saponified polyvinyl acetates, celluloses and the like can be used. From the viewpoint of compatibility with the photopolymerizable unsaturated compound, it is preferable to mainly use polyamide.

The present invention has found a photosensitive resin composition which can be developed with neutral water and can be applied to printing with an aqueous ink by utilizing such a characteristic property of a hydrophilic polymer, particularly a hydrophilic polyamide. It is.

The hydrophilic polyamide used in the present invention includes all conventionally proposed hydrophilic polyamides. For example, polyamides containing a sulfonic acid group or a sulfonate group obtained by copolymerizing sodium 3,5-dicarboxybenzenesulfonate as disclosed in JP-A-48-72250, No. 43465, a polyamide having an ether bond obtained by copolymerizing any one of a dicarboxylic acid, a diamine and a cyclic amide having an ether bond in a molecule;
No. 0-7605, a polyamide containing a basic nitrogen obtained by copolymerizing N, N'-di (γ-aminopropyl) piperazine and the like, and these polyamides are coated with acrylic acid or the like. Graded polyamide, having a molecular weight of 15 as proposed in JP-A-55-74537.
Copolymerized polyamide containing 0 to 1500 polyether segments, and ring-opening polymerization of α- (N, N′-dialkylamino) -ε-caprolactam or α- (N,
N′-dialkylamino) -ε-caprolactam and ε-
Examples include polyamides obtained by ring-opening copolymerization of caprolactam.

Among these hydrophilic polyamides, copolymerized polyamides containing a polyether segment having a molecular weight of 150 to 1500, more specifically, having a terminal amino group and a polyether segment having a molecular weight of 150 to 1500 are preferred.
A copolymer polyamide containing 1500 to 30% by weight of a structural unit composed of polyoxyethylene and an aliphatic dicarboxylic acid or a diamine is preferably used.

These hydrophilic polyamides may be used alone or as a mixture of two or more.

For use as a flexographic printing plate,
It is preferable that the base resin further contains rubber.
The rubber of the present invention refers to unvulcanized rubber or vulcanized rubber or both. The vulcanized rubber is obtained by vulcanizing an unvulcanized rubber. The unvulcanized rubber is not particularly limited, and a so-called solid rubber having a molecular weight of 40,000 or more is preferably used. For example, raw rubber or elastomer such as high molecular weight isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber, nitrile rubber, butyl rubber, acrylic rubber, epichlorohydrin rubber, silicone rubber, and styrene-
Butadiene copolymer, styrene-isoprene copolymer,
Examples include copolymers of dienes such as butadiene-acrylic acid copolymer, and copolymers of olefins such as ethylene-propylene copolymer and ethylene-vinyl acetate copolymer. Among them, copolymers of dienes or olefins are preferably used. As these unvulcanized rubbers, both self-vulcanizable and non-self-vulcanizable rubbers are suitable for the practice of the present invention. Non-self-vulcanizable rubbers require the presence of a vulcanizing agent to vulcanize the rubber at processing temperatures to a rubber gel content of at least about 80% or more. Self-vulcanizable rubber, as the name implies, vulcanizes at processing temperatures to the extent that the gel content of the rubber is at least about 80% or more without a vulcanizing agent.

In the present invention, the vulcanizing agent component of the rubber is not particularly limited, and vulcanizing agents and vulcanizing agents commonly used for vulcanizing diene rubber can be used. All vulcanizing agents and vulcanizing systems applicable to vulcanization of diene rubbers, such as peroxide, azide, quinoid or accelerated sulfur vulcanizing systems, can be used in the practice of the present invention. Combinations of maleimide and peroxide or disulfide accelerators can be used. A sufficient amount of vulcanizing agent is used to achieve essentially complete vulcanization of the rubber. Excess vulcanizing agents should be avoided. The reason for this is that much more than is necessary to completely vulcanize the rubber will result in poor properties, such as a loss of the water soluble and / or dispersible properties of the hydrophilic polymer.

In order to achieve both the water developability of the printing plate material and the compatibility of the printing plate with the aqueous ink, it is preferable that rubber is dispersed in these hydrophilic polymers. As a method of dispersing the rubber in the hydrophilic polymer, there is a method in which the hydrophilic polymer and the unvulcanized rubber are melt-mixed, and then, the unvulcanized rubber is vulcanized in some cases. Melt mixing refers to mixing two or more polymers at a temperature equal to or higher than the softening point.
By performing the melt mixing, the rubber particles having a small size are dispersed throughout the continuous hydrophilic polymer matrix, and thereafter, the rubber particles are vulcanized to obtain a desired blend polymer. The process for producing the blended polymer involves mixing the hydrophilic polymer with the unvulcanized rubber and, if required, a vulcanizing agent, and then subjecting the blend to conventional mastication at a temperature sufficient to effect vulcanization. The mixing is performed using an apparatus such as a mixing extruder such as a Banbury mixer, a Brabender mixer or a twin screw. The hydrophilic polymer and rubber are mixed at a temperature sufficient to soften the hydrophilic polymer, or more usually at a temperature above the melting point if the hydrophilic polymer is normal and crystalline. After intimate mixing of the hydrophilic polymer and the rubber, a vulcanizing agent is added if necessary. Heating and mastication at the vulcanization temperature is generally sufficient to complete the vulcanization formation in minutes or less. However, higher temperatures can be used if shorter times are desired. A suitable temperature range for the formation of vulcanization is from the melting temperature of the hydrophilic polymer to the decomposition temperature of the rubber, which is generally about 100 ° C.
~ 250 ° C, but its maximum temperature varies somewhat depending on the type of rubber, the presence of the antidegradant and the mixing time. Typically this range is between about 130C and 250C. A preferred range is from about 150C to 230C. In order to obtain a good rubber vulcanized blend polymer, it is important to continue mixing until the vulcanization occurs without stopping mixing.

The mixing ratio of the hydrophilic polymer to the rubber is preferably 1: 9 to 8: 2, more preferably 1: 9 by weight.
5 to 5.

The amount of the hydrophilic polymer used is preferably from 3 to 40% by weight, more preferably from 5 to 20% by weight in the whole photosensitive resin composition. When the amount is less than 3% by weight, the developability is lowered and the form retention of the raw plate is lowered. 4
If the amount is more than 0% by weight, the water resistance of the printing plate is reduced, and the printing durability is deteriorated.

The amount of rubber used is 1 in all photosensitive resin compositions.
It is preferably from 0 to 80% by weight, more preferably from 30 to 70% by weight. The rubber includes not only a rubber of a blended polymer but also a rubber emulsion added at the time of preparing the photosensitive resin composition and fine particles of vulcanized rubber. When the amount is less than 10% by weight, the flexibility of the printing plate is reduced. When the amount is more than 80% by weight, the developability is reduced.

The component (A) which is a feature of the present invention has three or more hydroxyl groups, amide bonds and hydrocarbon groups having 6 or more carbon atoms in the molecule. Further, the number of hydroxyl groups is preferably 5 or more. By having these functional groups, the compatibility between the hydrophilic polymer and other components, for example, rubber, can be improved, and the rubber has an average particle diameter of 0.001 to 10 μm in the hydrophilic polymer.
By dispersing as m particles, water developability is significantly improved.

As the component (A), an N-alkylgluconamide compound represented by the following formula can be preferably used.

[0023]

Embedded image R-HNCO (CHOH) ₄ CH ₂ OH (wherein R is an alkyl group having 6 to 24 carbon atoms) ”In the N-alkylgluconamide compound of the present invention represented by the above general formula, R is a straight-chain or branched-chain alkyl group, and the alkyl group having 6 to 24 carbon atoms is suitable for the purpose of the present invention. If the carbon number of the alkyl group is less than 6, the moldability of the rubber-containing photosensitive resin composition tends to decrease, and if it is large, the properties as a printing plate tend to be lost. It is better to select from the range.

Examples of these N-alkylgluconamide compounds include N-hexylgluconamide, N-heptylgluconamide, N-octylgluconamide,
-Nonylgluconamide, N-decylgluconamide,
N-undecyl gluconamide, N-dodecyl gluconamide, N-tridecyl gluconamide, N-tetradecyl gluconamide, N-pentadecyl gluconamide, N-heptadecyl gluconamide, N-octadecyl gluconamide, N-nona Decyl gluconamide, N
-Eicosylgluconamide, N-heneicosylgluconamide, N-docosylgluconamide, N-tricosylgluconamide and the like.

As the addition of the component (A) to the rubber-containing photosensitive resin composition, one kind or two or more kinds can be appropriately selected and used. However, the amount used can vary depending on the type of the base resin used, for example, rubber or hydrophilic polymer, or the molding means, but is usually 0.01 to 20% by weight in the total photosensitive resin composition. Preferably, it is 0.1 to 10% by weight.

The component (A) of the present invention can be used in combination with a conventionally used lubricant or release agent.

The component (A) of the present invention may be used when kneading with the base resin in advance, and when preparing the rubber-containing photosensitive resin composition, a dye, a pigment, a surfactant, an antifoaming agent,
It can be kneaded and used together with various additives such as an ultraviolet absorber and a fragrance.

The total amount of the base resin is preferably 20 to 90% by weight, more preferably 50 to 80% by weight in the whole photosensitive resin composition. If the amount is less than 20% by weight, the obtained plate surface will have high adhesion or the plate will lose its shape retention. If the content is more than 90% by weight, the photosensitive characteristics of the plate, particularly the image reproducibility, will be reduced.

[0029] The polymerizable unsaturated compound (B) is added to the composition of the present invention. Specifically, the following are mentioned. 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl acrylate, 2-hydroxybutyl methacrylate, 3
-Chloro-2-hydroxypropyl acrylate, 3-
Monoacrylates and monomethacrylates having a hydroxyl group such as chloro-2-hydroxypropyl methacrylate. Polyhydric acrylates and methacrylates obtained by reacting a polyhydric alcohol such as ethylene glycol with an unsaturated carboxylic acid such as acrylic acid or methacrylic acid. Unsaturated epoxy compounds such as glycidyl acrylate, glycidyl methacrylate, 3,4-epoxycyclohexyl acrylate and 3,4-epoxycyclohexyl methacrylate; Polyhydric acrylates and polyhydric methacrylates having a hydroxyl group which are synthesized by the reaction of a polyhydric glycidyl ether such as ethylene glycol diglycidyl ether and an unsaturated carboxylic acid such as acrylic acid and methacrylic acid. Polyhydric acrylates and methacrylates having a hydroxyl group, which are synthesized by reacting an unsaturated epoxy compound such as glycidyl methacrylate with an unsaturated carboxylic acid such as acrylic acid or methacrylic acid. Acrylamide, methacrylamide, N-methylol acrylamide, N-methylol methacrylamide, diacetone acrylamide, methylenebisacrylamide, N-methylol acrylamide or polyhydric acrylamide obtained by condensation reaction of polyhydric alcohol with N-methylol methacrylamide and polyhydric acrylamide Acrylamide-based photopolymerizable monomers such as methacrylamide and the like, and preferably, acrylic or methacrylic esters having a hydroxyl group and acrylic or methacrylamides are used.

The proportion of the component (B) in the photosensitive resin composition is preferably in the range of 10 to 80% by weight. More preferably, it is 10 to 60% by weight. When the proportion of the component (B) in the photosensitive resin composition is less than 10% by weight, the density of a crosslinked structure generated by photopolymerization is insufficient, so that the solvent for a water-based aqueous ink diluent is insufficient. Swelling is likely to occur, and swelling and destruction of the solid portion during printing and poor printing are likely to occur. In addition, sufficient image reproducibility cannot be obtained due to insufficient crosslinking density. In addition, if a photopolymerizable unsaturated compound having higher crosslinkability is used to obtain high quality image reproducibility, the plate hardness of the printing plate material is increased, and the ink adhesion to a printing material is reduced, and a good printed material is obtained. become unable. Conversely, if the proportion of the photopolymerizable unsaturated compound in the photosensitive resin composition is large, the density of the crosslinked structure generated becomes excessive, and thus the relief made by the plate-making tends to crack during printing.

In the present invention, a photopolymerization initiator is blended as the component (C). This has the ability to initiate polymerization of the component (B) by light irradiation. For example, there are benzoin alkyl ethers, benzophenones, anthraquinones, benzyls, acetophenones, diacetyls and the like. These photopolymerization initiators can be used in the range of 0.01 to 10% by weight based on the total amount of the photosensitive resin composition.

In the photosensitive resin composition of the present invention, ethylene glycol, diethylene glycol, triethylene glycol, glycerin, trimethylolpropane, and trimethylol may be used as a compatibilizer between the base resin, in particular, the hydrophilic polymer and the photopolymerizable unsaturated compound. Polyhydric alcohols such as ethane,
It is also possible to add N-ethyl-p-toluenesulfonamide, N-butylbenzenesulfonamide, N-methylbenzenesulfonamide and the like. These polyhydric alcohols and sulfonamide compounds have the effect of increasing the flexibility of the photopolymerized portion and preventing the occurrence of relief cracks. Such polyhydric alcohols and sulfonamide compounds can be used in a range of 30% by weight or less based on the photosensitive resin composition.

In order to improve the thermal stability of the photosensitive resin composition of the present invention, a conventionally known polymerization inhibitor can be used. Preferred thermal polymerization inhibitors include phenols, hydroquinones, catechols and the like. These thermal polymerization inhibitors are used in an amount of 0.0
It can be used in the range of 01 to 5% by weight. Also,
Dyes, pigments, surfactants, defoamers, ultraviolet absorbers, fragrances and the like can be added.

The method for producing the composition of the present invention includes:
For example, by heating and dissolving a blend polymer of a hydrophilic polymer and a vulcanized rubber in a mixed solvent of water / alcohol,
After only the hydrophilic polymer is dissolved and the micro-dispersed rubber in the molten mixture diffuses into the solution, the unsaturated epoxy compound is added to cause an addition reaction to the polymer. Then, it is common to add a photopolymerizable unsaturated compound, a photopolymerization initiator, and a heat stabilizer, stir and mix well. Thus, a photosensitive resin solution is obtained.

By adding an unsaturated epoxy compound to the solution of the molten mixture of the hydrophilic polymer and the rubber and adding the unsaturated epoxy compound to the terminal carboxyl groups of the hydrophilic polymer and the rubber, the polymer or the rubber itself can be photopolymerized. The relief network created by the photopolymerization reaction with the photopolymerizable compound is formed at a higher density, and the resulting relief has good water resistance and can maintain high image reproducibility. In addition, since the relief is tough, problems such as cracking during printing can be prevented.

In order to form a photosensitive layer from the above-mentioned mixed solution, for example, most of the solvent can be distilled off, then heated to a molten state and extruded onto a support. It is also possible to form a photosensitive sheet by a dry film-forming method and bond the sheet to a support to form a photosensitive layer. Further, the photosensitive layer can be obtained by dry film formation directly on the support. As the support, a metal plate such as steel, stainless steel, aluminum, or copper, a plastic sheet such as a polyester film, or a synthetic rubber sheet such as a styrene-butadiene copolymer is used. The photosensitive layer is preferably formed to a thickness of 0.01 to 10 mm. By coating the photosensitive resin composition of the present invention on the support in this manner, a photosensitive resin plate material can be obtained.

In order to form a printing plate using the photosensitive resin plate material of the present invention, a negative or positive original film is brought into close contact with the photosensitive layer prepared as described above, and a wavelength of about 300 to 400 mμ is usually applied. UV light from a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a xenon lamp, a carbon arc lamp, or a chemical lamp is used to insolubilize by photopolymerization. Next, the unpolymerized portion is eluted in water with a spray developing device or a brush developing device using neutral water to form a relief on the support.

After drying, the plate can be treated with actinic rays in the air or in a vacuum to obtain a printing plate.

The photosensitive resin composition of the present invention has high image reproducibility and, if necessary, flexibility as a flexographic printing plate, has good water developability, and is compatible with aqueous inks. Is satisfied.

This is because the photosensitive resin composition itself can be made water developable by adding a certain ratio of the hydrophilic polymer and the rubber, and since the water-insoluble rubber is contained, the flexibility of the printing plate is increased. And further improved the resistance to aqueous inks obtained by dissolving the resin in a solvent containing water as a main component.

[0041]

The present invention will be described below in detail with reference to examples.

The parts used in the following examples are parts by weight, and unless otherwise specified, the number average molecular weight is a value determined by a combination of a viscosity measurement method and a GPC method. The relative viscosity [ηr] was measured at 25 ° C. by dissolving the polymer in 98% sulfuric acid at a rate of 1 g / 100 cc.

Hereinafter, synthetic examples of the hydrophilic polyamide used in each example will be described.

Synthesis Example A-1: Equimolar salt of ε-caprolactam / hexamethylenediamine and adipic acid / equimolar salt of α, ω-diaminopropylpolyoxyethylene (number average molecular weight 1000) and adipic acid = 20/20 / 60 The terminal group of the copolymerized polyamide obtained here was determined to be 4.0 × 10 −5 mol / g of primary amino group and 2.1 × 10 −5 mol / g of carboxyl group. The number average molecular weight by the method was approximately 33,000.

A-2: 113 g of ε-caprolactam, 17.6 g of hexamethylenediamine and 66 g of α-aminocaproic acid were charged in an autoclave, and after purging with nitrogen, the contents were reacted at a temperature of 230 ° C. for 3 hours. . After cooling, 2 mmg of 3-hydroxy-butanesulfonic acid lactone and 13.8 g of potassium sulfate were added to the reaction mixture, and the mixture was replaced with nitrogen and reacted again at a temperature of 230 ° C for 1 hour to obtain a copolymerized polyamide.

A-3: 50 parts of N, N, -di (γ-aminopropyl) piperazine adipate, 30 parts of ε-caprolactam, 20 parts of water and 0.3 parts of n-butylamine are autoclaved. After being charged into the reactor and being purged with nitrogen, tightly closed and gradually heated. From the time when the internal pressure reached 10 kg / m ³ , water was distilled off until the pressure could not be maintained, the pressure was returned to normal pressure in about 2 hours, and then the reaction was performed at normal pressure for 1 hour. The highest polymerization reaction temperature was 255 ° C. The obtained polymer was a transparent pale yellow polyamide having a softening point of 90 to 105 ° C. and [ηr] of 2.3.

A-4: 90 parts of α-dimethylamino-ε-caprolactam and 10 parts of water are charged into an autoclave, replaced with nitrogen, sealed, and gradually heated. Internal pressure is 3.
When the pressure reached 5 kg / m ³ , water was distilled off until the pressure could not be maintained, the pressure was returned to normal pressure in about 2 hours, and the reaction was performed at normal pressure for 2 hours. The maximum polymerization temperature is 260
° C. [Ηr] of the obtained polymer was 2.5.

Example 1 20 parts of the copolymerized polyamide obtained in Synthesis Example A-1 and a carboxylated nitrile-butadiene rubber (Nipol 1072) were used using an internal mixer operated at 160 ° C.
20 parts of Nippon Zeon Co., Ltd. and partially cross-linked nitrile butadiene rubber (Nipol DN214 Nippon Zeon Co., Ltd.)
20 parts) and 40 parts of butadiene rubber (Nipol BR-1220L made by Nippon Zeon Co., Ltd.) were melt-mixed for 10 minutes, and then m
0.2 part of phenylene bismaleimide was added and the total mixing time was 15 minutes. The form of the polymer blend was observed with a scanning electron microscope (JSM-T300, manufactured by JEOL Ltd., measurement conditions: reflection electron composition image). As a result of the observation,
It was confirmed that the rubber obtained by vulcanizing the A-1 polymer in the sea had a sea-island dispersion structure in which islands were formed, and the diameter of the spherical body was in the range of 0.5 to 4 microns.

Forty parts of the polymer blend thus obtained and 2 parts by weight of sodium methylenebisnaphthalenesulfonate were kneaded with a closed mixer at 160 ° C. for 3 minutes, and then butadiene latex (Nipol LX111NF) was mixed.
Non-volatile content 55% Nippon Zeon Co., Ltd.) Solid content conversion 1
0 parts, carboxy-modified acrylic butadiene latex (LM511-1 50% non-volatile content 50%, manufactured by Dainippon Ink and Chemicals, Inc.) solid content 15 parts, and phenoxy polyethylene glycol acrylate 2 as a polymerizable unsaturated compound
0 parts by weight and glycerin diglycidyl diacrylate 10
Parts by weight and 2 parts by weight of N-stearyl gluconamide (Plastrogin J manufactured by Fujisawa Pharmaceutical Co., Ltd.) and added at 140 ° C.
For 15 minutes, and 1 part by weight of dimethylbenzyl ketal as a photoinitiator was added, followed by kneading at 140 ° C. for 10 minutes. The photosensitive resin composition obtained in this manner was
In a press machine heated to 0 ° C., the thickness of the photosensitive layer is placed between a 100 μm-thick polyester substrate on which a polyester-based adhesive has been applied and cured in advance and a polyester cover film on which a polyvinyl alcohol has been applied in advance. Saga 17
The printing plate material was obtained by pressing the photosensitive resin composition so as to have a thickness of 00 μm.

The form of the plate material was observed with a scanning electron microscope (JSM-T300, manufactured by JEOL Ltd., measuring conditions: reflection electron composition image). As a result of the observation, it has a sea-island dispersion structure composed of an A-1 polymer and a sea composed of a photopolymerizable unsaturated compound, and an unvulcanized rubber and an island of vulcanized rubber. It was confirmed that it was in the range of 4 microns.

On the photosensitive layer of this printing plate material, a gray scale negative film for sensitivity measurement (manufactured by Stoffer, 2
1 Steps Sensitivity Guide)
And negative film for image reproducibility evaluation (150 lines 3%,
5%, 10% halftone dots, 200 μm diameter and 300 μm
Independent points, widths of 50 and 70 μm with fine lines) were brought into close contact with each other in a vacuum, and exposure was performed for 5 minutes from a distance of 5 cm with an exposure apparatus in which 15 20 W high-intensity chemical lamps were arranged.

After the completion of the exposure, development was carried out using a brush type washing machine (solution temperature 35 ° C.) containing neutral water. A relief image having a depth of 1000 μm was formed in a developing time of 5 minutes. As a result of evaluating the relief image, it was found that the gray scale portion remained up to 16 steps, and the image portion almost completely reproduced 3% halftone dots, 200 μm independent points, 50 μm fine lines, and the like. The printing plate had a Shore A hardness of 55 after post-exposure of actinic rays. Using this printing plate, a flexographic printing test was performed on 100,000 sheets using an aqueous ink to obtain a good printed matter.

Comparative Example 1 A photosensitive resin printing plate material was obtained in the same manner as in Example 1 except that N-stearylgluconamide was not used. At this time, the moldability when pressing the photosensitive resin composition was poor. In order to obtain a printing plate in the same manner as in Example 1, after completion of exposure, a relief image having a depth of 1000 μm is formed with a brush-type washing machine (liquid temperature 35 ° C.) containing neutral water. The developing time was 25 minutes and was very slow.

Comparative Example 2 A printing plate was obtained in the same manner as in Example 1 except that montan wax (manufactured by Wax OP Hoechst Co., Ltd.) was used in place of N-stearylgluconamide. At this time, the moldability when pressing the photosensitive resin composition was good,
In order to obtain a printing plate in the same manner as in Example 1, after completion of exposure, a relief image having a depth of 1000 μm is formed with a brush-type washing machine (liquid temperature 35 ° C.) containing neutral water. The development time was as long as 20 minutes and was very slow.

Comparative Example 3 The N-stearylgluconamide of Example 1 was replaced with ethylenebisstearic acid amide (Slipax E Nippon Kasei)
A printing plate was obtained in the same manner as in Example 1 except that the printing plate was replaced with a printing plate. At this time, the moldability when pressing the photosensitive resin composition was good. However, this printing plate material was brush-washed with neutral water after completion of exposure to obtain a printing plate in the same manner as in Example 1. It took 20 minutes to develop a relief image having a depth of 1000 μm with a dipping machine (liquid temperature of 35 ° C.), which was very slow.

Example 2 A printing plate was obtained in the same manner as in Example 1 except that 1 part by weight of N-stearylgluconamide was added when obtaining the polymer blend of Example 1. After the completion of the exposure, development was carried out using a brush-type washing machine containing neutral water (solution temperature 35 ° C.). With a development time of 4 minutes, a relief image having a depth of 1000 μm was formed. As a result of evaluating the relief image, it was found that the gray scale portion remained up to 16 steps, and the image portion almost completely reproduced 3% halftone dots, 200 μm independent points, 50 μm fine lines, and the like. The printing plate had a Shore A hardness of 53 after the completion of the post-exposure of the actinic ray. Using this printing plate, a flexographic printing test was performed on 100,000 sheets using an aqueous ink to obtain a good printed matter.

[0057]

The photosensitive resin composition for a printing plate of the present invention comprises:
Excellent image reproducibility, and has good water developability,
This satisfies compatibility with aqueous inks. Furthermore, when a hydrophilic polymer and rubber are used as the base resin, flexibility as a flexographic printing plate is provided.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI G03F 7/037 G03F 7/037

Claims (8)

[Claims] (A) a compound having at least three hydroxyl groups, an amide bond and a hydrocarbon group having 6 or more carbon atoms in a molecule,
A photosensitive resin composition for a printing plate, comprising (B) a polymerizable unsaturated compound and (C) a photopolymerization initiator. 2. The method according to claim 1, wherein the component (A) is a compound represented by the general formula (I):
The photosensitive resin composition for a printing plate according to claim 1, which is an alkyl gluconamide compound. ## STR1 ## _{R-HNCO (CHOH) 4 CH} 2 OH ( wherein, R is an alkyl group having 6 to 24 carbon atoms) 3. The photosensitive resin composition for a printing plate according to claim 2, wherein the composition contains 0.01 to 20% by weight of the N-alkylgluconamide compound. 4. The photosensitive resin composition for a printing plate according to claim 1, further comprising a base resin. 5. The printing plate photosensitive resin composition according to claim 4, wherein the base resin contains a hydrophilic polymer and a hydrophobic rubber. 6. The photosensitive resin composition for a printing plate according to claim 5, wherein the vulcanized rubber and the unvulcanized rubber are dispersed in the hydrophilic polymer. 7. A photosensitive resin plate material obtained by coating the photosensitive resin composition for a printing plate according to claim 1 on a support. 8. The photosensitive resin plate material according to claim 7, which is for flexographic printing.