JPH0527419A - Photosensitive resin plate - Google Patents

Abstract

PURPOSE:To uniformly prevent the adhesion of the surface of the photo-sensitive layer of a photosensitive resin plate. CONSTITUTION:A layer of a mixture of perfectly or partially saponified polyvinyl acetate with a water-soluble cellulose deriv. is formed on the surface of a photosensitive layer contg. polyvinyl alcohol as base resin on a substrate. The mixture satisfies an inequality a/(a+b)>=0.95 [where a is the amt. (pis. wt.) of the polyvinyl acetate and b is the amt. (pts. wt.) of the cellulose deriv.].

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive resin plate used for forming a plate surface for letterpress printing, and more specifically, it suppresses tackiness caused on the surface of a photosensitive layer and causes troubles. The present invention relates to a photosensitive resin plate that prevents

[0002]

2. Description of the Related Art Polyvinyl alcohol (hereinafter "PVA")
Since a photosensitive layer containing a) as a base resin contains a large amount of a photopolymerizable monomer, a plasticizer, etc., it often has tackiness on the surface of the photosensitive layer. Therefore, when exposing the original film (negative film) and the photosensitive layer in close contact, uniform adhesion between the original film and the photosensitive layer is obstructed, or when the original film is peeled from the photosensitive layer after exposure. ,
There is a problem that a part of the surface of the photosensitive layer is transferred to the original film and the original film and the photosensitive layer are damaged.

As a method for solving such a problem, the following method has been proposed. A method in which a film having a microporous surface is pressure-bonded to the surface of the photosensitive layer and then peeled to form a matte surface of the photosensitive layer (JP-A-48-45304), which does not remain on the surface of the photosensitive layer after exposure and development. PVA
(Japanese Patent Application Laid-Open Nos. 51-49,803, 52-110,010 and 58-58)
No. 18,633, Japanese Patent Application Laid-Open No. 61-17,148), a method of forming a specific polyvinyl alcohol film remaining on the surface of a photosensitive layer after exposure and development (Japanese Patent Publication No. 3-2).
No. 7,109, Japanese Patent Laid-Open No. 1-287,671)
and so on.

[0004]

However, in the method (1), the photosensitive layer has only irregularities and the tackiness itself has not been improved, so that the adhesiveness to the original film cannot be sufficiently enhanced.

In another method, the photosensitive layer and PVA are used.
The coating easily peels off, and when the cover film provided on the PVA coating is peeled off, the PVA coating adheres to the cover film side and components such as photopolymerizable monomers contained in the photosensitive layer surface diffuse into the PVA coating. However, the photosensitive layer has non-uniform photosensitivity. As a result, a part of the PVA coating cured during exposure remains as spots on the pattern after development, and a good printing plate cannot be obtained.

Furthermore, Japanese Patent Publication No. 3-27,109 discloses a method of providing an anti-adhesion layer containing PVA and a water-soluble cellulose derivative, but the amount of the water-soluble cellulose derivative used is small. Otherwise it will not have the effect,
There is a problem that the more the water-soluble cellulose derivative is used, the more the tackiness increases.

Further, JP-A-1-287,671 discloses that the saponification degree is in the range of -10 to 10 mol% and the polymerization degree is 0 with respect to the completely saponified or partially saponified PVA used in the photosensitive layer. There is disclosed a photosensitive resin plate in which an anti-adhesion layer made of completely saponified or partially saponified PVA in the range of 0.5 to 1.5 times is provided on the surface of the photosensitive layer. However, such a PVA coating has a forming ability. Not only bad, but pinholes are likely to occur,
When the film is brought into close contact with the original drawing film, a partial poor adhesion occurs.

[0008]

The present invention solves these problems and, in a photosensitive resin plate having photosensitivity using PVA as a base resin, uniformly prevents the tackiness of the surface of the photosensitive layer, and The purpose of the present invention is to provide a photosensitive resin plate capable of reproducing a clear image without uneven printing pressure during printing.

The inventors of the present invention are keen to develop a photosensitive resin plate capable of uniformly preventing tackiness of the surface of the photosensitive layer and capable of reproducing a clear image without uneven printing pressure during printing. As a result of repeated studies, it was found that the object can be achieved by providing a specific layer composed of PVA and a water-soluble cellulose derivative on the surface of the photosensitive layer, and the present invention was completed based on this finding.

That is, according to the present invention, a layer of a mixture of completely saponified or partially saponified polyvinyl acetate and a water-soluble cellulose derivative is provided on the surface of a photosensitive layer having polyvinyl alcohol as a base resin provided on a support, When the amount of fully saponified or partially saponified polyvinyl acetate is a part by weight and the water-soluble cellulose derivative is b part by weight, the mixture ratio (a / a + b) of the mixture is 0.95 or more.

The support used in the present invention includes:
Although not particularly limited, examples thereof include resin films such as polyester, polyamide, and polystyrene that are used in conventional photosensitive resin plates, and plates such as iron and aluminum provided with an antihalation layer.

The photosensitive layer using the PVA as the base resin of the present invention is a resin having the completely saponified or partially saponified PVA as the base resin, a photopolymerizable monomer having at least one photopolymerizable alkenyl group, Also, a composition containing a photopolymerization initiator as a main component and, if necessary, a thermal polymerization inhibitor, a coloring agent such as a dye or a pigment, and a plasticizer is used.

The component (1) can be appropriately selected depending on what is used as the developing solution. For example, when the aqueous solution is used as the developing solution, the aqueous solution PVA may be used. In this case, the degree of saponification of PVA is about 65 to 98%.
It is desirable to set the range to. Further, the PVA may be a modified PVA having an unsaturated group introduced therein.

The completely saponified or partially saponified polyvinyl alcohol constituting the mixture layer provided on the surface of the photosensitive layer of the present invention has a polymerization degree of 300 to 1000 and a saponification degree of 70.
It is preferably ˜100 mol%. Degree of polymerization is 300
If it is smaller than the above, there is no film forming ability of PVA,
Moreover, the anti-adhesion effect is small. If the degree of polymerization exceeds 1,000, the development time is unduly increased during development, which is not preferable. If the saponification degree is less than 70, the anti-adhesion effect is not exhibited.

On the other hand, examples of the water-soluble cellulose derivative constituting the mixture layer include carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, ethyl cellulose, ethyl hydroxyethyl cellulose and carboxymethyl ethyl cellulose.

When the fully saponified or partially saponified polyvinyl alcohol constituting the mixture layer is a part by weight and the water-soluble cellulose derivative is b part by weight, the mixture ratio (a / a + b) of these mixtures is 0. It is necessary to be 95 or more. If it is less than 0.95, the anti-sticking effect is small,
Further, when the water-soluble cellulose derivative is not used, that is, when the ratio is 1, the film forming ability is small and pinholes are generated, which is not preferable. The above-mentioned components constituting the mixture layer may be used alone or in combination of two or more.

Further, the mixture layer is usually used in the range of 0.1 to 20 μm, preferably 0.5 to 4 μm. If it is less than 0.1 μm, the anti-adhesion effect is lowered. On the other hand, when it exceeds 20 μm, light scattering occurs in the mixture layer during exposure through the original drawing film, resulting in poor image reproducibility. If necessary, a surfactant, a plasticizer, a photopolymerizable monomer, and a photopolymerization initiator may be added to the mixture layer of the present invention within a range that does not reduce the anti-adhesion effect.

A cover film may be further covered on the mixture layer of the photosensitive resin plate of the present invention to protect the plate surface. Examples of such a cover film include, but are not limited to, polyester, polyamide, polystyrene, polypropylene, polycarbonate, polyvinyl chloride, polyvinylidene chloride, polyacrylate and polymethacrylate.

When a matte film is used for these cover films, the mixture layer is also matted, so that the adhesion to the original film can be further improved. As a method of matting the surface of the cover film,
For example, a chemical polishing method in which the surface of the film is treated with an alkali or an acid to corrode the surface, a sand blast method in which fine particles are sprayed onto the film surface to form irregularities on the surface, and water containing fine particles is sprayed onto the film surface. There are a liquid honing method for forming irregularities on the film surface, a coating method for coating the film surface with a resin containing fine particles, and the like. Among these methods, the coating method is advantageous because the surface roughness can be made constant.

As an example of a suitable method for producing the photosensitive resin plate of the present invention, a mixture layer comprising PVA and a water-soluble cellulose derivative is formed on the photosensitive layer. In this case, the following method is recommended. A method in which a mixture layer of PVA and a water-soluble cellulose derivative is applied on a cover film with a solution dissolved in a solvent such as water and / or methanol, and the dried one is pressed onto the surface of a photosensitive layer formed on a support, A method of forming a mixture layer composed of PVA and a water-soluble cellulose derivative on the surface of a photosensitive layer formed on a support and laminating a cover film if necessary, a method of coating a solution composed of PVA and a water-soluble cellulose derivative on the cover film and drying the solution. Then, there is a method in which a photosensitive layer is cast thereon, dried, and a support is laminated on the surface of the photosensitive layer via an adhesive. The photosensitive resin plate obtained in this way has a uniform coating without pinholes on the photosensitive layer. Image exposure is possible.

[0021]

The present invention will be described in more detail by way of examples, which should not be construed as limiting the invention thereto.

Example 1 10 parts by weight of PVA having a saponification degree of 99 mol% and a degree of polymerization of 300, 0.3 parts by weight of hydroxypropylethylcellulose (Metronose 65SH50 manufactured by Shin-Etsu Chemical Co., Ltd.), 120 parts by weight of water, and 60 parts by weight of methanol A mixed layer forming solution was prepared by dissolving the mixed layer forming solution in parts. This solution was applied on a polyester film having a membrane pressure of 125 μm to serve as a cover film and dried at 100 ° C. for 2 minutes to form a 1 μm thick mixture layer. On the other hand, the photosensitive layer has a saponification degree of 73 mol%, a polymerization degree of 500, and 100 parts by weight of partially saponified PVA,
100 parts by weight of photosensitive reaction product, ethylene glycol 1
0 parts by weight, benzoin isopropyl ether 4 parts by weight,
A solution prepared by heating 0.05 parts by weight of methylhydroquinone in 200 parts by weight of water was cast on a polyester film having an antihalation layer provided beforehand and dried at 40 ° C. for 15 hours to form a photosensitive layer having a thickness of 0.7 mm. Formed.

The photosensitive reaction product was prepared by dissolving 0.25 part by weight of methylhydroquinone in 10 parts by weight of water, and adding 74 parts by weight of dimethylol ether, 202 parts by weight of N-methylolacrylamide, and 2 parts by weight of ammonium chloride. Was added and the mixture was heated to 80 ° C. and stirred for 2 hours. Next, this reaction product was poured into 1000 parts by weight of acetone, and the precipitate was filtered off to obtain a polymeric condensate (photosensitive reaction product).

The surface of the photosensitive layer thus formed had strong adhesiveness, and the vacuum adhesion to the original film was extremely poor. So water: methanol = 1: 2 on this surface
(Weight ratio) of the mixed solvent was applied thinly, and the cover film having the mixture layer formed thereon was laminated and pressure-bonded so that the mixture layer was in contact with the photosensitive surface to prepare a photosensitive resin plate.

Next, when the cover film of the obtained photosensitive resin plate was peeled off, the mixture layer was transferred and adhered to the surface of the photosensitive layer, and the surface of the mixture layer was not tacky. Further, when an original drawing film was placed on this photosensitive resin plate and vacuum-adhered, the original film was evenly adhered to the surface of the photosensitive resin plate. Subsequently, after exposure with a chemical lamp, the original drawing film was peeled off. As a result, it could be easily peeled off and the surface of the photosensitive layer was not damaged.

Then, using a brush type washing machine, 3
Development was performed for 2 minutes with warm water at 5 ° C., followed by drying and post-exposure. When the printing plate on which the pattern was formed was observed, the edge portion of the image was sharp and the image reproducibility was good with no blurring. When this plate was put on a printing machine and a printing test was conducted, a good printed matter was obtained.

Comparative Example 1 5 parts by weight of PVA having a saponification degree of 99 mol% and a weight degree of 300,
Hydroxypropyl ethyl cellulose (Shin-Etsu Chemical Co., Ltd.)
5 parts by weight of METOLOSE 65SH50) manufactured by K.K., was dissolved in a mixed solvent consisting of 120 parts by weight of water and 60 parts by weight of methanol to prepare a mixture layer forming solution. This solution is applied to a film thickness of 125
Apply it on a polyester film of μm and
Dry for 1 minute to form a 1 μm thick mixture. This was pressure-bonded onto the photosensitive layer obtained in Example 1 to prepare a photosensitive resin plate.

When this photosensitive resin plate was made in the same manner as in Example 1, the surface of the photosensitive layer was tacky. When the original films were stacked and vacuum-adhered, the original film and the photosensitive layer were evenly adhered. I couldn't. Further, when the formed pattern was observed, the image edge portion was rounded, and burning blur was generated.

Comparative Example 2 10 parts by weight of PVA having a saponification degree of 99 mol% and a weight of 300 was dissolved in a mixed solvent of 120 parts by weight of water and 60 parts by weight of methanol, and this was coated on a 125 μm polyester film, The film was dried at 2 ° C. for 2 minutes to form a film having a thickness of 1 μm, but many pinholes were generated in this film.

On the photosensitive layer obtained in Example 1, a photosensitive resin plate pressure-bonded was prepared. When the cover film was peeled off and the original film was stacked and vacuum-contacted, the mixture layer could not be evenly adhered because the portion where many pinholes were generated was sticky. Further, exposure, development, drying and post-exposure were carried out in the same manner as in Example 1 to prepare a printing plate, which was observed. As a result, a circular burning blur having a diameter of about 5 mm occurred.

Example 2 10 parts by weight of PVA having a saponification degree of 88 mol% and a polymerization degree of 500, methyl cellulose (manufactured by Shin-Etsu Chemical Co., Ltd., SM-
100) 0.2 parts by weight of water, 120 parts by weight of water, 6 parts of methanol
A solution dissolved in 0 part by weight was used as a mixture layer forming solution. On the other hand, a cyclohexanone solution of 5% of a saturated polyester resin having a weight degree of about 20,000 was prepared and used as a solution for forming an adhesive layer.

The above adhesive layer forming solution was applied onto a polyester film having a thickness of 125 μm so that the dry film thickness was 1 μm, and dried at 150 ° C. for 1 minute, and then the mixture layer forming solution was changed to a dry film thickness of 2 μm. And apply 120
After drying at 30 ° C. for 30 seconds, a film composed of a polyester film, an adhesive layer and a mixture layer was formed. The mixture layer at this time was able to form a uniform film and had no defects.

As the photosensitive resin plate composition, 100 parts by weight of PVA having a degree of saponification of 90 mol% and a degree of polymerization of 500, 80 parts by weight of a reaction product obtained by reacting polyglycerin with N-methylol acrylamide, polyethylene glycol 20 parts by weight of acrylate, 1 part by weight of benzoin isopropyl ether, 0.05 part by weight of methylhydroquinone and 10 parts of water
What was heated and melt | dissolved in 0 weight part was prepared. This photosensitive resin solution was cast on a polyester film provided with an antihalation layer in advance and dried at 40 ° C. for 15 hours to form a photosensitive layer having a thickness of 0.7 mm. This photosensitive layer had a strong adhesive force and had poor vacuum adhesion to the original drawing film.

Onto the surface of the photosensitive layer, the three-layer film prepared above was pressure-bonded so that the mixture layer was in contact with the surface of the photosensitive layer. A plate was prepared in the same manner as in Example 1 using the obtained photosensitive resin plate. When the original film was overlaid and vacuum-contacted, the original film could be evenly adhered to the surface of the photosensitive resin plate. The obtained printing plate was free from blurring and a sharp image was obtained.

Example 3 100 parts by weight of a saturated polyester resin having a degree of polymerization of about 20,000 was dissolved in 3800 parts by weight of cyclohexanone, and 10 parts by weight of silicon dioxide powder having an average particle diameter of 5 μm was dispersed therein to obtain Coronate L ( 2 parts by weight of an isocyanate compound manufactured by Nippon Polyurethane Co., Ltd. was added to obtain a coating agent for forming a matting layer. In addition, 100 parts by weight of a saturated polyester resin having a degree of polymerization of about 20,000 was added to cyclohexane380.
It was dissolved in 0 part by weight and used for forming an adhesive.

On the polyester film having a thickness of 125 μm, the coating agent for forming the matting layer is dried to a thickness of 4 μm.
It was applied so as to have m, and dried at 100 ° C. for 5 minutes in order to volatilize cyclohexanone. The surface roughness thus obtained was Ra = 0.5 μm. A solution for forming an adhesive layer was applied onto this so that the dry film thickness was 1 μm, and 10
It was dried at 0 ° C for 10 minutes. The film thus obtained is subjected to heat treatment at 60 ° C. for 4 days, and then the mixture layer-forming solution of Example 1 is applied on the adhesive layer so that the dry film thickness is 2 μm, and the temperature is 120 ° C. for 30 seconds. It dried and formed the laminated body which consists of a mat film, an adhesive layer, and a mixed compound layer. The photosensitive layer obtained in Example 1 was pressure-bonded to this laminate to prepare a photosensitive resin plate. The result was as good as in Example 1.

[0037]

As is apparent from the above description, according to the present invention, by providing the specific layer of PVA and the water-soluble derivative on the surface of the photosensitive layer, the tackiness of the surface of the photosensitive layer is uniformly prevented. In addition, it can be suitably used as a photosensitive resin plate capable of reproducing a clear image without uneven printing pressure during printing.

Claims (1)

Claim: What is claimed is: 1. A layer of a mixture of completely saponified or partially saponified polyvinyl acetate and a water-soluble cellulose derivative on the surface of a photosensitive layer comprising polyvinyl alcohol as a base resin provided on a support. And the total saponified or partially saponified polyvinyl acetate is a part by weight and the water-soluble cellulose derivative is b part by weight, the mixture ratio (a / a +) of the mixture is
A photosensitive resin plate characterized in that b) is 0.95 or more.