JPS60122937A - Photosensitive resin composition - Google Patents

Abstract

PURPOSE:To obtain a partially saponified polyvinyl acetate type photosensitive resin compsn. for preparing a printing resin plate superior in image reproducibility, printing aptitude, water-developability, etc., by incorporating a specified photopolymerizable vinyl monomer in a partially saponified vinyl acetate. CONSTITUTION:The present photosensitive resin compsn. is obtained by condensing glycerin in the presence of alkali to prepare polyglycerin represented by the formula, esterifying it with an unsatd. 3-40C carboxylic acid, such as acrylic or maleic acid, to prepare a photopolymerizable vinyl monomer, mixing 10-200pts. wt. of it with 100pts.wt. of polyvinyl acetate saponified by 60-99mol%, and further, when needed, a photosensitizer, such as benzophenone, a heat stabilizer, such as hydroquinone, a colorant, a UV absorber etc.

Description

Detailed Description of the Invention [Technical Yono] The present invention provides a photosensitive resin composition for use in a partially saponified polyvinyl acetate photosensitive resin plate that has high image reproducibility, printability, and good water developability. It is related to.

[Description of prior art]

Photosensitive resin plate materials for letterpress, lithographic and intaglio printing have recently been put into practical use, and have a structure in which a photopolymerizable photosensitive resin layer is provided on a metal or plastic substrate. These plate materials are made by attaching a negative or positive original film with a transparent part to a photosensitive resin layer, and then irradiating it with actinic rays to cause photopolymerization of the photosensitive resin layer corresponding to the transparent part of the original film. Then, a relief image is formed on the substrate by eluting the unpolymerized portion with a suitable solvent.

In this way, photosensitive resin compositions that utilize photopolymerization reactions are used for various purposes including printing plates. Among these, photosensitive resins that can be developed by eluting the unpolymerized portion with neutral water are those in which partially saponified polyvinyl acetate is used as a base polymer and a photopolymerizable monomer is blended with this to impart photosensitivity. has been put into practical use.

As a photopolymerizable vinyl monomer to be added to partially saponified polyvinyl acetate, 2-hydroxyethyl methacrylate is well known (for example, Japanese Patent Publication No. 39401/1983).

However, since 2-hydroxyethyl methacrylate is a 91-functional vinyl monomer having only one vinyl group in one molecule, the density of the six-dimensional structure formed by photopolymerization is insufficient. Therefore, the water control properties of the photopolymerized portion become insufficient, making it difficult to obtain a high degree of image reproducibility.

[Purpose of the invention]

An object of the present invention is to provide a water-developable partially saponified polyvinyl acetate photosensitive resin that has high image reproducibility and excellent printability.

[Structure of the invention]

The present invention relates to a photosensitive resin composition characterized by comprising primary A and B components.

A, 100 parts by weight of partially saponified polyvinyl acetate with a degree of saponification of 60 to 99 mol% B, an esterification reaction between polyglycerin represented by the following general formula and an unsaturated carboxylic acid having 3 to 40 carbon atoms. Photopolymerizable vinyl monomer obtained from 10 to 200
Parts by weight where n=0 to 20 Component A is partially saponified polyvinyl acetate having a degree of saponification of 60 to 99 mol%. If the degree of saponification is less than 60 molar, the water solubility of the polymer will drop significantly, making water development impossible when used in a 9 plate material. In addition, the degree of saponification is 10
Even in the case of 0 molt, it is difficult to use because the solubility in water at room temperature is very low. For the above reasons, the degree of saponification of the partially saponified polyvinyl acetate of component A is 60.
It needs to be in the range of ~99 mol%, more preferably 65-95 mol%.

Any degree of polymerization of component A can be used, but if the degree of polymerization is too low, the resulting relief will lack water resistance. On the other hand, if the degree of polymerization is too high, the water developability of i decreases. For these reasons, the degree of polymerization of component A is 200 to 40.
It is preferably in the range of 00. It is also possible to use two or more types of components having different degrees of saponification or degrees of polymerization together as component A, as long as the average degree of saponification after mixing is in the range of 60 to 99 mol%.

Partially saponified polyvinyl acetate with a double bond introduced by reacting an unsaturated epoxy compound such as glycidyl methacrylate with the terminal carboxyl group of partially saponified polyvinyl acetate (component A) or other monomers such as allyl sulfonic acid can be prepared. 1
Partially saponified polyvinyl acetate copolymerized in a small amount in the range of ~10 molar, and partially saponified polyvinyl acetate modified by reacting ethylene oxide to the hydroxyl group, as well as partially saponified polyvinyl acetate, etc. degree of oxidation is 60 to 99 mol%
It can be used if it satisfies the following range.

In addition, as component A, other polymers such as cellulose derivatives such as methylcellulose, polyalkylene oxides such as polyethylene oxide, copolymers of dialkylamino (meth)acrylate and 2-hydroxyethyl (meth)acrylate, etc. may be added in an amount of 1 to 20% by weight or less. It is also possible to mix and use it in a small amount range.

The photopolymerizable monomer used as component B in the present invention is obtained by an esterification reaction between polyglycerin and an unsaturated carboxylic acid having 5 to 40 carbon atoms.

The polyglycerin used in the present invention is a compound having a structure represented by the following general formula.

When condensing with glycerin in the presence of an alkali, n = 0 to 20. When n = 0, diglycerin has the lowest molecular weight among polyglycerin. If n exceeds 20, the molecular weight becomes too high and the compatibility between the obtained photopolymerizable vinyl monomer and component A rapidly decreases. Therefore, n is 0
It is essential that n=20, preferably n=
It ranges from 0 to 10.

The unsaturated carboxylic acid to be esterified with polyglycerin has 3. 40 and has a carboxyl group and an unsaturated group in the molecule, all of them have zero working capacity. Specifically, the following may be mentioned, but the invention is not limited to these.

Unsaturated carboxylic acids obtained by esterifying saturated polycarboxylic anhydrides such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, cinnamic acid, and phthalic anhydride with unsaturated alcohols such as 2-hydroxymethacrylate. etc. Among these, acrylic acid and methacrylic acid are particularly preferably used.

The number of carbon atoms in the unsaturated carboxylic acid must be in the range of 6 to 40. Acrylic acid, which is an unsaturated carboxylic acid with the smallest molecular weight, has 6 carbon atoms. Number of carbons is 40
If it exceeds 1, the molecular weight of the unsaturated carboxylic acid becomes too large, resulting in an excessive molecular weight of the compound Y; For the above reasons, the number of carbon atoms needs to be in the range of 3 to 40, preferably kj, ro to 30.

The photopolymerizable monomer of component B can be obtained by esterifying the hydroxyl group of polyglycerin and the carboxyl group of an unsaturated carboxylic acid.

This reaction is carried out under nine standard esterification conditions.

It is also possible to obtain the same product by using an anhydride as the unsaturated carboxylic acid and reacting it with the hydroxyl group of polyglycerin. Since polyglycerin has (n+4) hydroxyl groups as shown in the general formula, any number of them can be esterified with an unsaturated carboxylic acid. In order to obtain good image reproducibility, it is preferable to introduce one or more unsaturated bonds on average per molecule of the B component. Since the remaining hydroxyl group has the function of imparting compatibility to component B with component A, it is preferable to leave an average of one or more hydroxyl groups in one molecule. In this way, the ratio of hydroxyl groups to unsaturated groups in one molecule of the photopolymerizable vinyl monomer is 1.
It is determined by the molar ratio of polyglycerin and unsaturated carboxylic acid to be reacted.

The amount of component B used must be in the range of 10 to 200 parts by weight based on 100 parts by weight of partially saponified polyvinyl acetate of component A. If it is less than 10 parts by weight, sufficient image reproducibility cannot be obtained because the density of the six-dimensional structure formed by photopolymerization is insufficient. On the contrary, 200
If the amount exceeds the weight part, the density of the three-dimensional structure becomes excessive and the relief becomes brittle, causing problems such as cranking during printing. From the above, it is necessary that the amount of component B used is in the range of 10 to 200 parts by weight, preferably 30 to 150 parts by weight, per 100 parts by weight of component A. It is also possible to use two or more types of B components together.

In the photosensitive resin composition of the present invention, ethylene glycol, diethylene glycol, triethylene glycol, glycerin, cycloheptaline, or It is also possible to add polyhydric alcohols such as methylolpropane and trimethylolethane. These polyhydric alcohols can be used to increase the flexibility of the photopolymerizable portion.
The effect of preventing relief cracks from occurring is also recognized.

Such polyhydric alcohol can be used in an amount of 30% by weight or less based on the photosensitive resin composition.

All conventionally known compounds can be used as the photosensitizer for quickly carrying out the photopolymerization reaction of the composition of the present invention. For example, benzoin alcohol ethers, benzophenones, anthraquinones, benzyls,
Acetophenones.

Examples include diacetyls. These photosensitizers are
It can be used in a range of 0.01 to 10% by weight based on the total composition.

All conventionally known polymerization inhibitors can be used to increase the thermal stability of the photosensitive composition of the present invention. Preferred thermal polymerization inhibitors include phenols, hydroquinones, catechols, and the like. These heat stabilizers 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 method for preparing the composition of the present invention includes heating and dissolving the partially saponified polyvinyl acetate as component A in a mixed solvent of water/alcohol, and then adding the photopolymerizable monomer and photosensitizer as component B, and the heat stabilizer as component B. Add agents, etc.

It is common to mix thoroughly by stirring.

The following method can be used to form a photosensitive layer from the photosensitive resin solution thus obtained. for example,
After most of the solvent is distilled off, it can be heated to a molten state and extruded onto a support to be shaped. It is also possible to form a photosensitive layer by making a photosensitive sheet by a dry film forming method and adhering this sheet onto a support. Furthermore, the photosensitive layer can also be obtained by dry film forming directly on the support. The support is made of steel or stainless steel.

Metal plates such as aluminum and copper, plastic sheets such as polyester filtrate, and synthetic rubber sheets such as styrene-butane copolymer are used. The photosensitive layer is 0
It is preferable to form it to a thickness of 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 film is closely adhered to the photosensitive layer prepared as described above.
Ultraviolet rays from a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metalnolide lamp, a xenon lamp, a carbon arc lamp, or a chemical lamp having a wavelength of 00 to 400 mμ are irradiated to effect insolubilization by photopolymerization. Next, a relief is formed on the support by dissolving the unpolymerized portion into water using a spray developing device or a brush developing device using neutral water.

The photosensitive composition of the present invention has good water developability and provides a printing plate material with high image reproducibility and durability during printing. This is achieved by introducing an arbitrary unsaturated group into one molecule of the photopolymerizable vinyl monomer of component B by controlling the molecular weight of polyglycerin and the molar ratio of polyglycerin and unsaturated carboxylic acid during esterification. This is because it is possible to leave any hydroxyl group.

In other words, it has become possible to select a photopolymerizable vinyl monomer as component B that has an optimum amount of unsaturated groups in relation to the partially saponified polyvinyl acetate as component A. In this respect, there is novelty not found in conventional photosensitive resin compositions.

The photosensitive resin composition of the present invention is most effective when used as a letterpress printing material, but it can also be used as a lithographic printing material, an intaglio printing material, a stencil printing material, or a photoresist.

The present invention will be explained in more detail with reference to Examples below.

Example 1 A photopolymerizable vinyl monomer was synthesized as follows. First, 1 mole of polyglycerin with the following structural formula and 25 moles of acrylic acid were placed in a trisol flask with a trap, and esterification was carried out under reflux for 4 hours using benzene as a solvent and sulfuric acid as a catalyst. caused a reaction.

From the measurement results of the hydroxyl value and infrared absorption spectrum of the reaction product obtained by distilling off benzene after neutralization and washing with water, it was found that an average of 25 of the 5 water groups in the polyglycerin above were acrylic. An acryloyl group is introduced by reacting with an acid, and an average of 2.
It was found that 5 hydroxyl groups remained.

Next, 100 parts by weight of partially saponified polyvinyl acetate with saponification degree of 80 mol% and ml: Ix600 was added to ethanol/water = 5
The mixture was dissolved in 200 parts by weight of a mixed solvent of 0.0150 (weight ratio) by heating at 80°C. To this was added 80 parts by weight of the photopolymerizable vinyl monomer obtained previously, and 2 parts of dimethylbenzyl ketal as a photosensitizer.

Hydroquinone monomethyl ether 0 as a heat stabilizer
．． 1 part by weight was added and thoroughly stirred and mixed.

The photosensitive resin solution thus obtained was poured onto a steel substrate (thickness 270μ) that had been coated with a polyester/diisocyanate adhesive and cured in advance so that the total thickness after drying was 950μ. It was extended. This is 60
The solvent was removed by placing it in a hot air oven at °C for 4 hours.

After storing the obtained photosensitive resin plate material in the dark for one week,
Test negative film (135 lines, 5 inches).

10% halftone dot part 1 width 50μ and 70μ thin line part, diameter 20
(0 μ and 300 μ independent point portions) were vacuum-adhered and exposed for 2 minutes with an ultra-high pressure mercury lamp. Next.

Spray type washing machine filled with 60℃ tap water (pressure 4K)
g/cIn2) for 4 minutes to completely remove unpolymerized portions. As a result of examining the obtained relief, 5 halftone dots, 5
It was found that 0μ thin lines, 200μ independent points, etc. were reproduced without problems.

A printing test was carried out using the plates obtained as described in UJ, 2 and L, and printing of up to 500,000 sheets was completed without any problems such as occurrence of relief cracks.

The print quality of the obtained printed matter was very sharp and good.

Example 2 Diglycerin having the following structural formula was selected as polyglycerin. A photopolymerizable vinyl monomer was obtained by esterifying 1 mole of this with 1.5 moles of methacrylic acid.

0HOH0HOH From the analysis results of the photopolymerizable vinyl monomer obtained, it was found that methacryloyl groups were introduced into an average of 1.5 of the 4 hydroxyl groups of polyglycerin, and an average of 2.5 hydroxyl groups remained. .

Next, 100 parts by weight of partially saponified polyvinyl acetate with a degree of saponification of 90 mol/1 degree of polymerization of 1000 was added to ethanol/water = 30/
It was heated and dissolved in a mixed solvent of 70' (weight ratio) at 80°C. 'To this, the previously obtained photopolymerizable vinyl monomer 6Of
1 part of fi, 10 parts by weight of diethylene glycol, 2 parts by weight of the photosensitizer penzoin isoglopylether, and 0.01 part by weight of the heat stabilizer hydroquinone were added and mixed with thorough stirring.

The photosensitive resin solution thus obtained was coated with epoxy adhesive and cured in advance to a thickness of 700 μm.
on an aluminum substrate with a total dry thickness of 125 mm.
Casting was carried out so that the thickness was 0μ. This was placed in an oven at 60° C. for 3 hours to remove the solvent.

The same test negative film as in Example 1 was vacuum-adhered to the obtained photosensitive resin plate and exposed to ultraviolet light from a chemical lamp for 5 minutes. Next, the film was developed for 2 minutes using a brush-type washing machine containing tap water at 30° C. to completely remove unpolymerized portions. As a result of examining the obtained relief, it was confirmed that it had sufficient image reproducibility.

Example 3 A polyglycerin having the following structural formula was esterified with 1 mole of polyglycerin, 4 moles of acrylic acid, and 2 moles of methacrylic acid to obtain a photopolymerizable vinyl monomer. As a result of analysis, it was confirmed that this photopolymerizable vinyl monomer contained an average of 4 acryloyl groups, an average of 2 methacryloyl groups, and an average of 8 hydroxyl groups.

Next, 100 parts by weight of partially phosphorized poly(vinyl chloride) having a degree of saponification of 70 molar and a degree of polymerization of 400 was mixed with ethanol/water.
180 parts by weight of a 60/40 (weight ratio) mixed solvent at 80°C
Dissolved by heating. To this, 40 parts by weight of the photopolymerizable vinyl monomer obtained previously, 20 parts by weight of the photopolymerizable vinyl monomer obtained in Example 1, 10 parts by weight of 2-hydroxyethyl methacrylate, and 4 parts by weight of benzophenone as a photosensitizer. 1 part and thoroughly stirred and mixed.

The photosensitive resin solution thus obtained was placed in a vacuum kneader at 80° C., and the solvent was distilled off to concentrate the remaining solvent to 8 g (weight). This was led to an extruder at 90°C, and a polyester film (thickness 200μ) coated with a polyester adhesive was coated with a total thickness of 40°C.
It was discharged from the nozzle so that the concentration was 0μ. Next, a polyester film (thickness 100 μm) whose surface had been matted by chemical etching was laminated on the surface of the photosensitive layer, and a cover film was attached.

Place the obtained photosensitive resin plate with cover film in a dark place.
After storage for a week, the cover film was peeled off and Example 1
Exposure and development were carried out in the same manner as above.

When the obtained relief was examined, it was confirmed that it had sufficient image reproducibility. Furthermore, from the results of the printing test, it was found that it had good printability.

Patent applicant Higashi Shikikai Co., Ltd.

Claims (1)

[Scope of Claims] A, 100 parts by weight of partially saponified polyvinyl acetate with a degree of saponification of 60 to 99 mol.B, polyglycerin represented by the following general formula and an unsaturated carboxylic acid having 6 to 40 carbon atoms A photosensitive resin composition which is obtained by an esterification reaction and is photopolymerizable, where n=Q~20.