JP2002055447A - Photosensitive resin composition, printing original plate comprising the same and method for producing printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive resin composition excellent in developability and image reproducibility, formable after heat melting and used for producing a relief printing plate. SOLUTION: (1) The photosensitive resin composition contains a partially saponified polyvinyl acetate having 20 to <50 mol% saponification degree and a photopolymerizable unsaturated compound having an ethylenic double bond in its molecule. (2) In the photosensitive resin composition (1), the photopolymerizable unsaturated compound is contained by 20-300 pts.wt. based on 100 pts.wt. partially saponified polyvinyl acetate. (3) An anionic surfactant may further be contained in the photosensitive resin composition (1). (4) An original plate for printing with at least a substrate and a layer of the photosensitive resin composition (1) is provided. In a method for producing a printing plate by exposing the original plate (4) and developing it with a developing solution, an anionic surfactant is contained in the developing solution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a photosensitive resin composition,
The present invention relates to a method for producing a printing original plate and a printing plate comprising the same, and in particular, to provide a photosensitive resin composition for preparing a relief plate for printing that is excellent in developability and image reproducibility, and that can be subjected to hot melt molding. is there.

[0002]

2. Description of the Related Art In general, a photosensitive resin composition used for a printing relief plate contains a soluble polymer photopolymerizable unsaturated group-containing compound and a photopolymerization initiator as essential components. An additive such as a plasticizer is compounded.

The photosensitive resin composition is irradiated with actinic rays through a negative film (or a positive film) having a transparent image area to cure the photosensitive layer in the exposed area, and then the unexposed area of the photosensitive layer is appropriately cured. By dissolving and removing with a solvent,
Creating relief molds for printing purposes is widely known.

As described above, photosensitive resin compositions utilizing a photopolymerization reaction often use partially saponified polyvinyl acetate as a soluble polymer which can be developed by dissolving and removing unpolymerized portions with neutral water. Proposed. For example,
JP-B-46-39401, JP-B-50-30903, JP-A-50-27602, JP-A-48-87903, JP-A-57-124730, JP-A-57-212217, JP-A-59-172644, JP-A-59-172644, No. 60-51833. Since these partially saponified polyvinyl acetates are developed with neutral water, a water-soluble or water-swellable partially saponified polyvinyl acetate having a degree of saponification of 50 mol% or more and at least 60 mol% or more is proposed. Have been. As is well known, the softening temperature of polyvinyl acetate rises sharply with the increase of the saponification degree, and at least the saponification degree is 60
When it becomes water-swellable or water-soluble at mol% or more, the melting point of the polymer becomes close to its thermal decomposition temperature, and the thermoplasticity becomes poor. Therefore, in order to form the photosensitive resin composition into a sheet, a solution casting method such as casting a photosensitive resin composition containing a solvent such as water into a sheet and then heating for a long time is adopted. However, this method has a problem that the productivity is inferior to the melt molding method in which the photosensitive resin composition is molded into a sheet in a molten state.

[0005] In addition, the partially saponified polyvinyl acetate becomes less compatible with the photopolymerizable unsaturated group-containing compound with an increase in the degree of saponification, and becomes a highly hydrophilic photopolymerizable compound such as an acrylamide-based compound or a compound containing a hydroxyl group. Only compounds containing unsaturated groups become compatible. This is very disadvantageous in the design of the photosensitive resin composition, and the performance of the photopolymer is limited, and specifically, the image reproducibility is inferior.

[Problems to be solved by the invention]

[0006] Partially saponified polyvinyl acetate is a material which is suitable as a raw material polymer for a photosensitive resin composition because of its good heat and light stability and its cost and safety. Therefore, the degree of saponification is limited. The present invention relates to a photosensitive resin composition comprising a partially saponified polyvinyl acetate as a base resin, and an object of the present invention is to improve the conventional disadvantages and to be useful for making a relief plate, that is, a hot-melt method. An object of the present invention is to provide a photosensitive resin composition which can be molded and has excellent developability and image reproducibility.

[0007]

The inventors of the present invention have made intensive studies, studies, and studies to solve the above-mentioned problems, and have finally completed the present invention. That is, the present invention provides a photosensitive composition comprising partially saponified polyvinyl acetate having a degree of saponification of at least 20 mol% and less than 50 mol%, and a photopolymerizable unsaturated compound having an ethylenic double bond in the molecule. Resin composition. The photosensitive resin composition as described above, wherein 20 to 300 parts by weight of the photopolymerizable unsaturated compound is mixed with 100 parts by weight of partially saponified polyvinyl acetate. The photosensitive resin composition as described above, further comprising an anionic surfactant. An original printing plate comprising at least a support and the above-described photosensitive resin composition layer. A method for producing a printing plate using the developer by exposing the printing plate precursor to light as described above, wherein the developer contains an anionic surfactant.

[0008] The partially saponified polyvinyl acetate having a degree of saponification of 20 mol% or more and less than 50 mol% used in the present invention is a method in which polyvinyl acetate having a degree of polymerization of 100 to 3000 is prepared by using an acid or alkali catalyst. And can be obtained by saponification. If the average degree of polymerization is less than 100, the water resistance is poor and the strength is low. On the other hand, if the degree of polymerization exceeds 3,000, the developability is lowered or the viscosity becomes high, making it difficult to handle. More preferably, the average degree of polymerization is from 200 to 2,000.

In the present invention, the degree of saponification is 20 mol%.
It is at least 50 mol%, preferably 25 to 45 mol%, particularly preferably 30 to 45 mol%. Saponification degree 50
If it is not less than 13 mol%, the flow temperature of the photosensitive resin composition is 13%.
When the temperature becomes 0 ° C. or higher, gelation easily occurs and melt molding becomes difficult. If the saponification degree is less than 20 mol%, the melting point of the polymer decreases to around 50 ° C., and the temperature at which the physical properties of the photopolymer of the photosensitive resin composition decreases near room temperature, which is not practically preferable. In addition, the drawback that organic solvent resistance is deteriorated becomes significant.

Next, the photopolymerizable unsaturated group-containing compound used in the present invention is a compound containing one or more photopolymerizable unsaturated groups in the molecule, and known compounds can be used. Examples of such compounds include alkyl esters such as acrylic acid and methacrylic acid, hydroxyethyl acrylate, hydroxypropyl acrylate, acrylamide, methacrylamide, N-methylolacrylamide, N-acryloylmorpholine, pentaerythritol diacrylate, and pentaerythritol triacrylate. Acrylate, glycerol dimethacrylate, polyhydric acrylate obtained by subjecting polyhydric glycidyl ether such as ethylene glycol diglycidyl ether to a compound having an ethylenically unsaturated bond and active hydrogen such as unsaturated carboxylic acid or unsaturated alcohol by addition reaction, Of unsaturated epoxy compounds such as methacrylate, glycidyl acrylate and methacrylate and compounds having active hydrogen such as carboxylic acids and amines Pressurized reactant, such as unsaturated polyesters or unsaturated polyurethanes. These monomers can be used alone or in combination of two or more.

These photopolymerizable unsaturated group-containing compounds include:
20 to 100 parts by weight of partially saponified polyvinyl acetate
300 parts by weight are blended, preferably 20 to 200 parts by weight, and particularly preferably 50 to 150 parts by weight. Further, the content of the photopolymerizable unsaturated group-containing compound in the photosensitive resin composition is preferably 5 to 75% by weight, more preferably 10 to 75% by weight.
~ 65% by weight, especially 15-60% by weight is desirable. If the amount is less than 5% by weight, the photocurability is poor, and an image hardly remains after development. Conversely, if it is more than 75% by weight, the curing shrinkage is undesirably large.

As the initiator, any of those conventionally known as photopolymerization initiators can be used. Specifically, benzophenones, benzoins, acetophenones, benzyls, benzoin alkyl ethers, benzylalkyl ketals, anthraquinones, thioxanthones and the like can be used. Specific examples include benzophenone, benzoin, acetophenone, benzoin methyl ether, benzoin ethyl ether, benzyldimethyl ketal, anthraquinone, 2-chloroanthraquinone, thioxanthone, and 2-chlorothioxanthone. These are preferably contained in the photosensitive resin composition in an amount of 0.05 to 5% by weight. When the amount is less than 0.05% by weight, the photopolymerization initiation ability is hindered. When the amount is more than 5% by weight, photocuring in the thickness direction is deteriorated, and an image is easily chipped.

In the photosensitive resin composition of the present invention, hydroquinone, hydroquinone monomethyl ether, cuperon, diethylhydroxylamine, 2,6-di-t-butyl-p-cresol, etc. may be added as a stabilizer in addition to the above.
You may make it contain 1-5 weight%. Further, the physical properties of the photo-cured product can be changed by adding a low-molecular plasticizer such as an ester or an amide as a plasticizer, or an oligomer such as polyester, polyether, or liquid rubber. In addition, the photosensitive resin layer may be colored by adding a known dye or pigment to sharpen the formed image area. Further, as the anionic surfactant, for example, sodium laurylbenzenesulfonate, sodium lauryl sulfate, sodium oleate and the like are contained in an amount of 1% by weight to 5% by weight, preferably 1.5 to 4.5% by weight. Development with fresh water such as tap water becomes possible.

The composition of the present invention may be, for example, hot pressed, cast,
Alternatively, a sheet having a desired thickness can be formed by any known method such as melt extrusion and solution casting. The sheet is laminated on a support with or without a known adhesive. As the support, any material such as steel, aluminum, glass, a plastic film such as a polyester film, and a metal-deposited film can be used.

When a photosensitive resin plate comprising a photosensitive layer and a support is supplied as a raw plate, a protective layer is laminated on the photosensitive layer in contact with the photosensitive layer. The protective layer is made of a film-like plastic, for example, a polyester having a thickness of 1 to 3 μm, which is transparent and does not stick to a 125 μm-thick polyester film and is dispersed or dissolved in a developer.
A protective material applied with a thickness of m is used. By contacting this thin film with the photosensitive layer, even when the surface adhesion of the photosensitive layer is strong, the operation of peeling off the film-like plastic of the protective layer at the time of the next exposure operation of the protective layer can be easily performed. it can.

A layer of such a composition alone or a photosensitive original plate comprising this layer and a support are laminated by closely contacting a negative film or a positive film having a transparent image portion on the photosensitive layer, and When exposure is carried out by irradiating with actinic rays from above, only the exposed portions are insolubilized and cured. As the actinic ray, a light source such as a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a xenon lamp, and a chemical lamp, usually having a wavelength of 300 to 450 nm is used.

Then, a suitable solvent, especially a lower alcohol which is a solvent for dissolving or swelling the polyvinyl alcohol having a low degree of saponification of the present invention, or a water mixture thereof such as methanol, ethanol, propyl alcohol and the like. Mixtures containing from 10% to 50% by weight of water can be used. Further, an aqueous solution containing 0.5 to 10% by weight, preferably 1 to 8% by weight of an anionic surfactant can be used. Examples of the anionic surfactant include sodium laurylbenzenesulfonate, sodium lauryl sulfate, and sodium oleate. When the anionic surfactant is contained in the photosensitive resin composition as described above, development with fresh water such as tap water becomes possible. By these means, a letterpress having a clear image portion is obtained.
For this purpose, a spray developing device or a brush developing device can be used.

[0018]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. The number of parts in the examples is parts by weight. Example 1 Low saponification degree polyvinyl acetate (Saponification degree: 40 mol%:
680 parts of LM-10HD (manufactured by Kuraray Co., Ltd.) were mixed with 500 parts of methanol in a heating dissolution vessel with stirring for 2 hours at 60 ° C. to completely dissolve the polymer. A solution prepared by dissolving 30 parts of sodium laurylbenzenesulfonate in 10 parts of water, 10 parts of hydroquinone monomethyl ether, and 3 parts of an acrylic acid adduct of bisphenol A diglycidyl ether.
06 parts and 10 parts of benzyl dimethyl ketal.
Dissolved for minutes. Next, the temperature was gradually raised to distill off methanol and water, and concentrated until the temperature in the kettle reached 110 ° C.
At this stage, a viscous photosensitive resin composition having fluidity was obtained.

Next, a copolymerized polyester (Vylon RV)
-30SS manufactured by Toyobo Co., Ltd.), a polyfunctional isocyanate (Coronate L, manufactured by Nippon Polyurethane Co., Ltd.), and a reaction product of a brown dye coated with a 15 μm-thick film.
The photosensitive resin composition is cast by contacting the film with a μm polyester film as a support. 2 μm thick polyvinyl alcohol (AH-24 Nippon Synthetic Chemical Co., Ltd.)
The polyester film having a thickness of 125 μm coated with the coating of (1) was formed into a sheet-like laminate having a total thickness of 1080 μm using a laminator, with the coating side being in contact with the photosensitive resin composition. This sheet solidified into a hard plate at room temperature.

After storing the obtained raw plate for 7 days or more,
A 125 μm-thick polyester film was peeled off, and a test negative film (a gray scale negative film for sensitivity measurement and a negative film of an image for evaluating image reproducibility) were brought into close contact with each other under vacuum, and exposed to an ultra-high pressure mercury lamp for 40 seconds. Next, using tap water as a developer with a brush type washer (100 μmφ nylon brush, JW-A2-PD type manufactured by JEOL Ltd.),
A relief image was obtained by developing at 3 ° C. for 3 minutes. After further drying at 60 ° C. for 5 minutes with hot air and post-exposure with an ultra-high pressure mercury lamp for 30 seconds, the resulting relief was evaluated.
A 0 μm independent point and a 30 μm thin line were reproduced. As a result of performing a printing test with this relief, a printed matter having a sharp print without an image thickening was obtained.

Comparative Example 1 Low saponification degree polyvinyl acetate (Saponification degree: 65 mol%:
55 parts of SMR-30M (manufactured by Shin-Etsu Chemical Co., Ltd.) are mixed in 30 parts of methanol and 70 parts of water in a heating and melting vessel with stirring.
C. for 2 hours to completely dissolve the polymer. 01 parts of hydroquinone monomethyl ether, bisphenol A
A mixture of 439 parts of an acrylic acid adduct of diglycidyl ether and 10 parts of benzyldimethyl ketal was dissolved for 30 minutes, and the temperature was gradually raised to distill methanol and water. Above this point, the fluidity was lost and concentration was no longer possible. Since it was dissolved in the methanol / water mixture, it was confirmed that it was not due to a chemical reaction.

Example 2 Low saponification degree polyvinyl acetate (36 mol% saponification degree:
550 parts (SMR-30L, manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed with 500 parts of methanol in a heating and dissolving vessel with stirring at 60 ° C. for 1 hour to completely dissolve the polymer. 1.0 part of hydroquinone monomethyl ether, 0.2 parts of diethylhydroxylamine, 100 parts of diethylene glycol dimethacrylate, 339 parts of an acrylic acid adduct of propylene glycol diglycidyl ether and 10 parts of benzyldimethyl ketal are mixed for 30 minutes. Dissolved. Next, the temperature was gradually increased to distill methanol, and the temperature in the kettle was reduced to 11
The mixture was concentrated to 0 ° C. to obtain a fluid and viscous photosensitive resin composition.

A sheet-like laminate was formed in the same manner as in Example 1, and after exposure, developed using tap water as a developer, it was difficult to remove non-image areas. Therefore, when a developer in which 3% by weight of sodium dibutylnaphthalenesulfonate was dissolved in tap water was used, a clear relief image could be obtained in 8 minutes.

[0024]

As described above, according to the present invention, when a partially saponified polyvinyl acetate-based photosensitive resin composition is obtained, molding can be performed by a hot-melt method by using polyvinyl acetate having a lower saponification degree than before. It is possible, the image reproducibility is good, and the use of an anionic surfactant makes it possible to carry out aqueous development. Therefore, by adopting the present invention, the photosensitive resin can be used and provided in a wider range, which greatly contributes to the industry.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C08F 263/04 C08F 263/04 4J026 G03F 7/00 501 G03F 7/00 501 7/004 504 7/004 504 7/027 7/027 7/32 7/32. EA04 EA08 GA01 4J011 AA05 AC04 PA68 PA69 PC02 QA03 QA12 QA23 QA34 SA01 SA21 SA31 SA41 SA51 SA61 UA01 VA04 WA01 4J026 AA38 AC23 BA12 BA27 BA28 BA32 BB01 BB02 DB06 DB11 DB36 EA02 FA05 GA07 GA08

Claims (5)

[Claims] 1. A photosensitive composition comprising partially saponified polyvinyl acetate having a degree of saponification of at least 20 mol% and less than 50 mol% and a photopolymerizable unsaturated compound having an ethylenic double bond in the molecule. Resin composition. 2. The photosensitive resin composition according to claim 1, wherein the photopolymerizable unsaturated compound is blended in an amount of 20 to 300 parts by weight based on 100 parts by weight of the partially saponified polyvinyl acetate. 3. The photosensitive resin composition according to claim 1, further comprising an anionic surfactant. 4. An original printing plate comprising at least a support and the photosensitive resin composition layer according to claim 1. 5. A method for producing a printing plate by exposing a printing plate precursor according to claim 4 and using a developer, wherein the developer contains an anionic surfactant. Plate production method.