JPH0363736B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel water-developable photosensitive resin composition, which is a partially saponified polyvinyl acetate-based resin composition that provides a printing plate material with high image reproducibility and flexibility. This invention relates to a photosensitive resin composition.

There are several known examples of systems in which partially saponified polyvinyl acetate is used as a main resin as a photosensitive resin composition that utilizes a photoinsolubilization reaction by photopolymerization and can be developed with neutral water. Known examples can be roughly divided into two types. The first system imparts photosensitivity by blending partially saponified polyvinyl acetate with a photopolymerizable monomer mainly consisting of a monofunctional (meth)acrylic ester having a hydroxyl group (particularly (1977-39401, Special Publication 50-3041, Special Publication 52-27561). In addition, the second system is produced by reacting a compound having an unsaturated group with the hydroxyl group of partially saponified polyvinyl acetate.
It imparts photopolymerizability. (Tokuko Showa 48-
6962, JP 49-5923, JP 48-55282, JP 48-65292, JP 48-66151, JP 50-
30602, JP 50-45087, JP 54-138090).

Known examples of the first system mainly include monofunctional (meth)acrylic acid esters having a hydroxyl group and one unsaturated group, such as β-hydroxyethyl (meth)acrylate and β-hydroxypropyl (meth)acrylate. have been shown to be used as photopolymerizable monomers. These monofunctional ester monomers have extremely good compatibility with partially saponified polyvinyl acetate. Therefore, it plays a role in helping the polyfunctional ester and benzoin alkyl ether photosensitizer, which have poor compatibility with partially saponified polyvinyl acetate, to be compatible. However, in order to obtain sufficient compatibility, a large amount of monofunctional (meth)acrylic acid ester having a hydroxyl group must be used. Therefore, in this case, the crosslinked structure formed by photopolymerization has low three-dimensionality because it is a polymer mainly composed of monofunctional acrylic ester, and as a result, for example, the water resistance of the photocured part may be poor. It is often the case that a portion of the photocured portion dissolves into water during development. Therefore, it is difficult to apply it to printing plate materials that require a high degree of image reproducibility. In order to modify this point, for example,
-27602 proposes the use of polyfunctional unsaturated monomers having two or more unsaturated groups and more hydroxyl groups in the same molecule. Since this polyfunctional unsaturated monomer has three or more hydroxyl groups, it has good compatibility with partially saponified polyvinyl acetate, and the crosslinked structure formed by photopolymerization is formed by the polyfunctional unsaturated monomer. Since it uses , it has a high density. However, this crosslinked structure has strong hydrophilic properties due to the excessive number of bonded hydroxyl groups, resulting in insufficient water resistance of the photocured area, making it unsuitable for applications that require a high degree of image reproducibility. Have difficulty. As mentioned above, all known examples of attempts to impart photosensitivity by blending photopolymerizable monomers into partially saponified polyvinyl acetate have high sensitivity due to insufficient water resistance in the photocured part. It was difficult to put it into practical use for printing plate materials that require high image reproducibility.

Regarding the second series of unsaturated groups that impart photosensitivity to partially saponified polyvinyl acetate, Japanese Patent Publication No. 48-6962, Japanese Unexamined Patent Publication No. 48-66151,
Japanese Patent Application Laid-open No. 45087-1987 introduces unsaturated groups by reacting maleic acid or its derivatives with the hydroxyl groups of partially saponified polyvinyl acetate;
55282 is a cinnamate ester, and JP-A-48-65292 is a reaction with an unsaturated lactone in the same way. However, in order to obtain sufficient image reproducibility as a printing plate material simply by introducing unsaturated groups into partially saponified polyvinyl acetate, it is necessary to introduce a large amount of unsaturated groups. The partially saponified polyvinyl acetate polymer itself must have sufficient photopolymerizability. For this purpose, a large amount of hydroxyl groups, which impart water solubility to partially saponified polyvinyl acetate, must be replaced, resulting in a significant decrease in water developability. As described above, attempts to impart photosensitivity solely by introducing unsaturated groups into partially saponified polyvinyl acetate have difficulty achieving both high image reproducibility and good water developability. In order to improve these shortcomings, the N-
By reacting methylol acrylamide with the hydroxyl groups of partially saponified polyvinyl acetate to introduce unsaturated groups,
It is proposed to blend this polymer with a photopolymerizable (meth)acrylate. Also, JP-A-54
-138090 proposes introducing an unsaturated group into partially saponified polyvinyl acetate by reacting with an unsaturated aldehyde such as acrolein, and adding a photopolymerizable (meth)acrylate to this. . However, in these cases, since the unsaturated group introduced into the partially saponified polyvinyl acetate is not a (meth)acryloyl group, copolymerizability with the (meth)acryloyl group of the photopolymerizable monomer is poor. Therefore, the probability that the partially saponified polyvinyl acetate polymer participates in the crosslinking reaction formed by polymerization of the photopolymerizable monomer is low, and the expected improvement in image reproducibility is not observed.

As mentioned above, in known examples of using partially saponified polyvinyl acetate as the main resin and imparting photosensitivity using photopolymerization reactions, fine lines such as 133 lines, 3% halftone dots, and 50μ fine lines are used. It has been difficult to put this into practical use in printing plate materials that require image reproduction.

The present inventors have intensively studied a partially saponified polyvinyl acetate photosensitive resin composition that has high image reproducibility and is developable with neutral water, and as a result, has arrived at the present invention described below.

That is, the present invention relates to a photosensitive resin composition characterized by comprising the following components A, B, and C.

A Partially saponified polyvinyl acetate with saponification degree of 60 to 99 mol% 100 parts by weight B Molecular weight 2000 or less selected from the following groups (a), (b) and (c), 2 pieces in the same molecule 10 to 300 parts by weight of a polyfunctional (meth)acrylate having the above (meth)acryloyl groups and at the same time a number of hydroxyl groups not exceeding the number of (meth)acryloyl groups (a) Polyvalent glycidyl ether and (meth)acrylic (b) adducts of polyhydric glycidyl ethers and 2-hydroxyethyl (meth)acrylate; (c) adducts of glycidyl (meth)acrylates and saturated or unsaturated carboxylic acids, alcohols, primary or secondary Adduct C with a class amine A saturated compound having a hydroxyl group in the molecule and having a molecular weight of 1000 or less and a boiling point of 150°C or more selected from the group of glycerin, alkylene glycols, and polyalkylene glycols 1 to 60 parts by weight , a partially saponified polyvinyl acetate-based photosensitive resin composition developable with neutral water and excellent in image reproducibility and printing plate flexibility, comprising components A, B, and C as described above. It is.

Each component of the present invention will be explained in detail below.

The partially saponified polyvinyl acetate used as a raw material for component A has a degree of saponification of 60 to 99 mol%. If the degree of saponification is less than 60 mol%, the water solubility will drop significantly and water development will become impossible, so the lower limit of the degree of saponification is 60 mol%. Further, completely saponified polyvinyl acetate having a degree of saponification of 100 mol % cannot be used because of its poor solubility in water at room temperature and its poor compatibility with component B. Therefore, the upper limit of saponification degree is 99
It is mole%. For the above reasons, the partially saponified polyvinyl acetate of component A needs to have a degree of saponification of 60 to 99 mol%.

Regarding the molecular weight, any molecular weight can be used, but from the viewpoint of compatibility with component B, a polymerization degree of 200 to 2000 is preferable. It is also possible to use two or more types of components with different degrees of saponification or polymerization as component A.

Examples of polyfunctional (meth)acrylates having a molecular weight of 2000 or less of component B and having two or more (meth)acryloyl groups and a number of hydroxyl groups not exceeding the number of (meth)acryloyl groups in the same molecule include, for example: Examples include: However, it is not limited to this as long as it satisfies the conditions. Glycerol di(meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, trimethylolethane di(meth)acrylate, tetramethylolethane di(meth)acrylate
Obtained by the reaction of the epoxy group of polyvalent glycidyl ethers such as acrylate, tetramethylolethane tri(meth)acrylate, and ethylene glycol diglycidyl ether with the active hydrogen of an unsaturated carboxylic acid such as (meth)acrylic acid. Polyfunctional (meth)acrylates having two or more (meth)acryloyl groups and the same number of hydroxyl groups, as well as addition reactions of polyvalent glycidyl ether and unsaturated alcohols such as 2-hydroxyethyl (meth)acrylate. A polyfunctional (meth)acrylate having two or more (meth)acryloyl groups and the same number of hydroxyl groups obtained by
Conversely, unsaturated compounds with epoxy groups such as glycidyl (meth)acrylate and saturated or unsaturated carboxylic acids, alcohols, primary or secondary
A polyfunctional (meth)acrylate having two or more (meth)acryloyl groups and not exceeding the number of hydroxyl groups obtained by an addition reaction with a compound having active hydrogen such as a class amine. be. It is also possible to use two or more types of B components together.

Since these B components have a hydroxyl group in their molecules, they exhibit a certain degree of compatibility with the partially saponified polyvinyl acetate of A component, which is a hydrophilic polymer. Also,
Since it has two or more (meth)acryloyl groups in the same molecule, the crosslinked structure produced by photopolymerization of component B will be sufficiently three-dimensional and extremely dense. Furthermore, since the number of hydroxyl groups does not exceed the number of (meth)acryloyl groups, it is possible to prevent the water resistance of the resulting crosslinked structure from being degraded by excessive hydroxyl groups. For the above reasons, the water resistance of the photocured portion is good, and it is possible to obtain a high degree of image reproducibility.

For example, the amount of component B used is 100% of component A.
If the amount is less than 10 parts by weight, the density of the crosslinked structure produced by photopolymerization will be insufficient, making it impossible to obtain good image reproducibility. On the other hand, if the amount is 300 parts by weight or more, the crosslinked structure generated by photopolymerization becomes overcrowded, making the photocured part brittle and causing serious problems such as cracks. However, B
The amount of ingredients used is 10 to 300 parts per 100 parts by weight of ingredient A.
Must be in the range of parts by weight, 50 to 150
Parts by weight are the more preferred usage amounts. The B component is
Since it has a hydroxyl group in its molecule, its compatibility with component A is relatively good. However, the molecular weight is 2000
The molecular weight of component B is preferably 2,000 or less, since compatibility tends to decrease rapidly if the molecular weight exceeds 2,000.

Examples of the saturated compound having a hydroxyl group in the molecule having a molecular weight of 1000 or less and a boiling point of 150° C. or more as component C include the following. n
-Hexyl alcohol, heptyl alcohol, isoheptyl alcohol, n-octyl alcohol, isooctyl alcohol, n-decyl alcohol, benzyl alcohol, cyclohexanol, butyl cellosolve, phenyl cellosolve, hexyl cellosolve, 2-methoxymethoxyethanol, ethylene glycol, ethylene Glycol monoacetate, diethylene glycol, methyl carbitol, ethyl carbitol, butyl carbitol, diethylene glycol monoacetate, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, tetraethylene glycol, propylene glycol, dipropylene glycol, Tripropylene glycol, polyethylene glycol with a molecular weight of 1000 or less, polypropylene glycol with a molecular weight of 1000 or less, 1,
4-butanediol, 1,5-pentanediol, glycerin, glycerin monoacetate, glycerin diacetate, glycerin monobutyrate, glycerin dibutyrate, diglycerin, trimethylolmethane, trimethylolethane, trimethylolpropane, hexanetriol, tetra These include methylolmethane, tetramethylolethane, and triethanolamine. It is also possible to use two or more types of C components together.

The molecular weight of component C needs to be 1000 or less; if it is more than that, the compatibility with components A and B will be poor, so it cannot play a role in improving the compatibility of components A and B. Can not. The reason why the compatibility between the A component and the B component is improved by using the C component is estimated as follows, for example. That is, although component B has a hydroxyl group in its molecule and has some degree of compatibility with partially saponified polyvinyl acetate of component A, which is a hydrophilic polymer, for example, when the solvent is rapidly removed during plate formation, When removed or rapidly cooled, part of the B component often oozes out onto the surface of the plate, or phase separation of the A and B components occurs inside the plate, resulting in cloudiness. Furthermore, if the plate material is stored for a long time under high humidity conditions, development may be observed in which part of the B component gradually seeps into the plate surface. However, when component C is added, component C has a certain degree of compatibility with both component A and component B due to the action of its hydroxyl group, so it helps the compatibility between component A and component B. It seems that these problems can be solved by playing a role. Also, C
By adding the components, the moldability during plate production is also improved. When octyl alcohol or the like is used as component C, for example, it can be expected to have the effect of eliminating bubbles generated when a partially saponified polyvinyl acetate plate material is developed with water.

Generally, when a low molecular weight saturated compound such as component C is added to a photosensitive resin composition, photocurability deteriorates, and image reproducibility usually deteriorates rapidly. However, in the case of the present invention, component B is a polyfunctional (meth)acrylate having two or more (meth)acryloyl groups, so the crosslinked structure produced by photopolymerization is sufficiently three-dimensional and has a low density. Since the crosslinked structure does not contain excess hydroxyl groups, the water resistance of the photocured portion is extremely good. Therefore, even if a relatively large amount of the low molecular weight saturated compound of component C is contained, the water resistance of the photocured portion is only slightly reduced, and a high degree of image reproducibility can be maintained.

The boiling point of component C is 150°C or less,
Since it only serves as a solvent for the photosensitive resin composition and is removed from the printing plate during the drying process during printing, it plays the original role of helping the compatibility of components A and B during printing. I can't fulfill it.
Further, if the boiling point is 150°C or lower, if a portion remains inside the plate material, it will evaporate over time, causing a significant change in plate hardness over time. For the above reasons, it is necessary that the boiling point of component C be 150°C or higher.

Since component C has a boiling point of 150°C or higher, all or most of it remains inside the plate even after the plate is molded. Therefore, it also plays the role of imparting flexibility to the exposed plate, eliminates the problem of cracks in cold weather, and improves ink transferability.

If the amount of component C used is less than 1 part by weight per 100 parts by weight of component A, it will not be able to play a role in promoting compatibility between component A and component B. 60 on the contrary
If it is added in excess of parts by weight, the water resistance of the photocured area will be significantly reduced and the image reproducibility will be significantly reduced. From this, it is necessary that the amount of component C used is in the range of 1 to 60 parts by weight, preferably 5 to 60 parts by weight.
50 parts by weight.

All conventionally known compounds can be used as the photosensitizer for quickly carrying out the photopolymerization reaction of the composition of the present invention. Examples include benzoin alkyl ethers, benzophenones, anthraquinones, benzyls, acetonephenones, diacetyls, and the like. These photosensitizers can be used in an amount of 0.01 to 10% by weight based on the total composition.

All known thermal polymerization inhibitors can be used to increase the thermal stability of the compositions of the invention. Preferred thermal polymerization inhibitors include phenols, hydroquinones, catechols, etc., and can be used in an amount of 0.001 to 5% by weight based on the total amount of the composition. Furthermore, dyes, pigments, surfactants, antifoaming agents, ultraviolet absorbers, etc. can also be added.

The usual production of the composition of the present invention involves heating and dissolving the partially saponified polyvinyl acetate as the component A in a mixed solvent of water/alcohol, and then dissolving the polyfunctional (meth) component as the component B.
Acrylate, a saturated compound having a hydroxyl group as component C, a photosensitizer, a thermal polymerization inhibitor, etc. are added and stirred to mix thoroughly. In this way, a photosensitive resin solution is obtained.

In order to form a photosensitive layer from the above-mentioned mixed solution, the photosensitive layer can be formed by, for example, distilling off the solvent, drying, granulating the granulated product, and heating and pressing it onto a support using a press or the like. It is also possible to form a photosensitive sheet by a dry film forming method and adhere the sheet to a support to form a photosensitive layer. Furthermore, the photosensitive layer can also be obtained by dry film forming directly on the support. As the support, metal plates such as iron, stainless steel, aluminum, and copper, synthetic resin sheets such as polyester film, and synthetic rubber sheets such as styrene-butadiene are used. The photosensitive layer is preferably formed to have a thickness of 0.1 to 10 mm.

In order to form a relief image for printing using the photosensitive resin composition of the present invention, a negative or positive original image film is closely adhered to the photosensitive layer prepared as described above. UV light from a high-pressure mercury lamp, ultra-high-pressure mercury lamp, metal halide lamp, xenon lamp, carbon arc lamp, or chemical lamp is irradiated to effect curing by photopolymerization. Next, a relief is formed on the support by dissolving the uncured portion into water using a spray developing device or a brush developing device using neutral water.

The photosensitive composition of the present invention is developable with neutral water.
The present invention provides a photosensitive resin material that has a high degree of image reproducibility and can be applied to high-grade printing applications that require the reproduction of fine images such as 3% halftone dots of 133 lines and fine lines of 50 μm. This uses a partially saponified polyvinyl acetate as the component A, which has good water solubility, as the base polymer, a polyfunctional (meth)acrylate as the component B as the photopolymerizable monomer, and a saturated polyvinyl acetate with a hydroxyl group as the component C. This is because the compound improves the compatibility between component A and component B. That is, since component B has a hydroxyl group in its molecule, it has a certain degree of compatibility with component A, partially saponified polyvinyl acetate. However, since their compatibility is not always sufficient, phase separation and seepage onto the plate surface often occur during plate molding. Adding component C solves this problem, and components A and B become completely compatible. This is thought to be because component C has a certain degree of compatibility with component A and component B due to the action of the hydroxyl group in the molecule. When the plate material thus obtained is irradiated with actinic rays, the photopolymerization of component B proceeds rapidly and uniformly, and component A is produced by photopolymerization of the polyfunctional (meth)acrylate of component B. Uniformly and efficiently included in the dense crosslinked structure. Moreover, since the crosslinked structure formed by photopolymerization of component B is composed of polyfunctional (meth)acrylate, monofunctional (meth)acrylate
It has a much higher density than when the main component is acrylate, and the number of hydroxyl groups in component B is
Since the number is less than or equal to the number of (meth)acryloyl groups, the water resistance of the crosslinked structure itself is also good. Therefore, C
Even if the component contains a saturated compound with a hydroxyl group,
The photocured part has good water resistance and a high degree of image reproducibility. In addition, the C component is contained in the plate material after exposure and has the effect of imparting flexibility. As described above, each of the three components A, B, and C is an essential component of the photosensitive resin composition of the present invention, and by combining these three components, high image reproducibility and flexibility of the exposed plate are achieved. is obtained.

The photosensitive composition of the present invention exhibits its effects most when used as a letterpress material, but it can be used as a lithographic material,
It can also be used as an intaglio material, stencil material, and photoresist.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 Propylene glycol diglucidyl ether 1
2 moles of acrylic acid, 1% by weight of triethylbenzylammoniur chloride, and 0.1% by weight of hydroquinone monomethyl ether were placed in a 3-necked flask and heated to 800°C under nitrogen gas flow.
Allowed time to react. As a result of examining the infrared absorption spectrum of the obtained reaction product, it was found that the following hydroxyl group was
It was confirmed that a polyfunctional acrylate having two acryloyl groups was produced.

Saponification degree 80 as partially saponified polyvinyl acetate
The one with mol% and degree of polymerization of 500 was selected. 100 parts by weight of this partially saponified polyvinyl acetate was heated and dissolved at 80°C in a mixed solvent of ethanol/water (50/50 weight ratio). Next, 60 parts by weight of the bifunctional acrylate obtained by the addition reaction of propylene glycol diglycidyl ether and acrylic acid, 30 parts by weight of diethylene glycol, 2 parts by weight of dimethylbenzyl ketal as a photosensitizer, and thermal polymerization inhibited. 0.01 part by weight of hydroquinone was added as an agent and thoroughly stirred and mixed.

The photosensitive resin composition solution thus obtained was cast onto a 150μ thick polyester film coated with a polyester adhesive in advance so that the dry thickness was 950μ including the substrate. did. Then, the mixture was placed in a hot air oven at 60° C. for 5 hours to completely remove the solvent. The photosensitive layer obtained was transparent and no monomer seepage was observed on the plate surface.

The surface of the photosensitive layer thus obtained was thinly coated with a solvent of water/ethanol = 50/50 (weight ratio), and a cover film was attached by pressing a 100 μm thick polyester film onto the surface. This plate material was stored in the dark for 10 days.

Peel off the cover film of the plate material, and place a grayscale negative film for sensitivity measurement (Stouffer 21 Steps Sensitivity Guide) and a negative film for image reproducibility evaluation (133 lines, 3 lines) on the photosensitive layer.
%, 5%, and 10% halftone dots, diameters of 200μ and 300μ independent dots, widths of 50μ and 70μ with thin lines) were vacuum-adhered and exposed for 2 minutes with a high-pressure mercury lamp.

After exposure, development was carried out using a brush type washing machine (liquid temperature: 30°C) containing neutral water. After a development time of 2 minutes, the non-image area was completely dissolved into water, and a relief image could be obtained.

As a result of evaluating the obtained relief, it was found that the gray scale part remained up to 16 steps, indicating high sensitivity. It was confirmed that fine details such as 3% halftone dots, 200μ independent points, and 50μ thin lines were completely reproduced in the image area. The hardness of the printing plate is Shore D60
It was hot.

When a printing test was carried out using the plate material obtained in this manner, a sharp printed product with no thick lines was obtained.

Example 2 1 mole of ethylene glycol diglycidyl ether, 2 moles of methacrylic acid, 2% by weight of triethylbenzylammonium chloride, and 0.1% by weight of hydroquinone monomethyl ether were placed in a 3-necked flask and reacted at 80°C for 6 hours. It was found from the infrared absorption spectrum of the obtained reaction product that a polyfunctional methacrylate having two each of unsaturated groups and two hydroxyl groups having the following structure was produced.

As the saponified polyvinyl acetate, one with a degree of saponification of 71 mol% and a degree of polymerization of 600 was selected. 100 parts by weight of this partially saponified polyvinyl acetate was added to water/ethanol =
It was dissolved in a mixed solvent of 40/60 (weight ratio) at 90°C.
Next, 75 parts by weight of the bifunctional methacrylate previously obtained by reacting 1 mole of ethylene glycol diglycidyl ether and 2 moles of methacrylic acid, 23 parts by weight of trimethylolpropane, 2 parts by weight of photosensitizer dimethylbenzyl ketal, and thermal polymerization inhibition. 0.1 part by weight of hydroquinone monomethyl ether was added and thoroughly mixed with stirring.

The photosensitive resin solution thus obtained was cast onto a 250μ thick steel base coated with epoxy adhesive so that the dry thickness was 700μ (including the steel base). did. This is 60
The solvent was completely removed by placing it in an oven at ℃ for 4 hours.

After storing this plate material in a dark place for 5 days, the same test negative film as in Example 1 was vacuum-adhered to the photosensitive layer and exposed to a chemical lamp for 7 minutes. Then,
Developing was carried out using a spray type developing machine (liquid temperature: 35°C, pressure: 3 Kg/cm ² ) containing neutral water. In 4 minutes, the non-image area was completely eluted and a relief image was obtained.

When the obtained relief was evaluated, it was found that the gray scale remained up to 16 steps, indicating high sensitivity. Image is 3% halftone, 200μ
It was found that the independent point and 50μ thin line were reproduced. The hardness of the printing plate was Shore D55, and a flexible printing plate was obtained.

Example 3 1 mol of glycidyl methacrylate, 1 mol of methacrylic acid, 1% by weight of triphenylphosphine,
0.1% by weight of hydroquinone monomethyl ether was charged into a three-necked flask and reacted at 80°C for 9 hours. It was found from the infrared absorption spectrum of the reactant that a polyfunctional methacrylate having two unsaturated groups and one hydroxyl group was produced as shown below.

A partially saponified polyvinyl acetate with a degree of saponification of 90 mol% and a degree of polymerization of 800 was selected. 100 parts by weight of this partially saponified polyvinyl acetate was added to water/ethanol =
It was dissolved in a mixed solvent of 60/40 (weight ratio) at 70°C.
Next, 90 parts by weight of bifunctional methacrylate previously obtained by the addition reaction of glycidyl methacrylate and methacrylic acid, 10 parts by weight of ethylene glycol, and 5 parts by weight of benzophenone were added and thoroughly stirred and mixed.

The photosensitive resin solution obtained in this way is coated with epoxy adhesive beforehand.
Dry thickness on 350μ aluminum substrate
It was cast to a thickness of 700μ (including the substrate). This was placed in an oven at 60°C for 2 hours to completely remove the solvent.

After storing the obtained plate material in the dark for 3 days, the same test negative film as in Example 1 was vacuum-adhered to the photosensitive layer, and exposed for 1 minute with a high-pressure mercury lamp. Then, it was developed for 3 minutes using the same spray type developer as in Example 2 to obtain a relief image.

As a result of evaluating the obtained relief image, it was found that the gray scale part remained up to 15 steps. The image is 3
It was confirmed that % halftone dots, 200μ independent points, and 50μ fine lines were reproduced without any problems. Printing plate hardness is Shore D72
It was hot.

A printing test was conducted using this printing plate, and very sharp prints were obtained without thick lines. Furthermore, there were no problems such as cracks appearing on the printing plate during printing.

Claims (1)

[Scope of Claims] 1. A photosensitive resin composition comprising the following components A, B and C. A Partially saponified polyvinyl acetate with saponification degree of 60 to 99 mol% 100 parts by weight B Molecular weight 2000 or less selected from the following groups (a), (b) and (c), 2 pieces in the same molecule 10 to 300 parts by weight of a polyfunctional (meth)acrylate having the above (meth)acryloyl groups and at the same time a number of hydroxyl groups not exceeding the number of (meth)acryloyl groups (a) Polyvalent glycidyl ether and (meth)acrylic (b) adducts of polyhydric glycidyl ethers and 2-hydroxyethyl (meth)acrylate; (c) adducts of glycidyl (meth)acrylates and saturated or unsaturated carboxylic acids, alcohols, primary or Adduct with secondary amine C: 1 to 60 parts by weight of a saturated compound having a hydroxyl group in the molecule and having a molecular weight of 1000 or less and a boiling point of 150°C or higher selected from the group of glycerin, alkylene glycols and polyalkylene glycols.