JPH0617386B2 - Water-soluble photosensitive resin and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a photosensitive resin that is readily soluble in water and is versatile, and a method for producing the same.

[Conventional technology]

The photosensitive resin is used as a printing plate manufacturing material, a resist for metal corrosion processing, a photosensitive vehicle for paint or printing ink, or an image forming material on a substrate such as a film, a glass plate or a screen. Furthermore, it is also used as an immobilizing material for enzymes and microorganisms.

This photosensitive resin is generally roughly classified into an organic solvent or alkaline aqueous solution developing type and a water developing type, and as the former organic solvent or alkaline aqueous solution developing type photosensitive resin,
Conventionally, those having azide group, cinnamoyl group, acryloyl group and the like as photosensitive groups are known. However, these photosensitive resins are not always satisfactory in terms of sensitivity and price, and since they are water-insoluble, an organic solvent or alkaline aqueous solution must be used as a solvent for the resin and a developing solution, Handling is complicated in the coating and developing processes, and there is a problem in terms of safety and economy.

On the other hand, as the water-developable photosensitive resin, a composition of a water-soluble resin such as polyvinyl alcohol, gelatin, or a glue and a dichromate or a diazodium salt, or a polyvinyl alcohol resin in which a stilbazolium group or an analog group thereof is introduced. It has been known. However, the composition containing dichromate has a good cured film strength,
There is a problem in storage stability of the aqueous solution and the film, and there is a problem of environmental pollution due to hexavalent chromium. Further, the diazonium salt-containing composition is better in storage stability than the above dichromate-containing composition, but it is not yet sufficiently satisfactory, and further, the sensitivity and the strength of the cured film are high. Inferior to dichromate-containing compositions.

The polyvinyl alcohol-based resin having stilbazolium or its related group introduced has high sensitivity and excellent storage stability. However, since the photosensitive group is a quaternary ammonium ion, it tends to swell with water even after photoinsolubilization, and the water resistance of the cured film is poor.
Since quaternary ammonium ions are harmful to many microorganisms, the types of microorganisms that can be immobilized are limited. In addition, since the light absorption coefficient of the photosensitive group is as large as tens of thousands, if a material having a large film thickness is photoinsolubilized, the light does not penetrate to the lower part and sufficient resolution cannot be obtained. Further, since the photoinsolubilization is due to the dimerization reaction of the photosensitive group, the reaction efficiency rapidly decreases as the reaction progresses, and it takes time to completely react and become colorless.

[Problems to be Solved by the Invention]

It is an object of the present invention to provide a photosensitive resin which is water-soluble, has a relatively small extinction coefficient, has practically sufficient sensitivity, film strength and water resistance and is easy to handle, and a method for producing the same.

[Means for Solving the Problems]

As a result of intensive studies on new photosensitive polymer compounds, the present inventors have found that the object can be achieved by introducing pyridinium ylide into polyvinyl alcohol, and based on this finding, the present invention has been accomplished. .

That is, the present invention has the general formula The present invention provides a novel photosensitive resin characterized by comprising a polyvinyl alcohol derivative having a structural unit represented by and having a degree of polymerization of 300 to 3000.

In the polyvinyl alcohol derivative of the present invention, the pyridinium ylide unit is preferably in the range of 0.1 to 5 mol% with respect to the vinyl alcohol unit of polyvinyl alcohol or polyvinyl acetate. The photosensitive constitutional unit itself of the present invention has a hydrophilic structure with an ylide structure, but if it deviates from this range and excessively introduces the constitutional unit, the water solubility of the polymer is remarkably lowered and becomes insoluble in water. Will end up. However, if a polar solvent such as hydroalcohol, dimethylformamide, formamide, or dimethylsulfoxide, or a mixed solvent thereof with water is used as the solvent, the introduction rate of the photosensitive constituent unit can be further increased. The photosensitive resin of the present invention is a novel photocrosslinkable substance which is easily soluble in water and has high sensitivity, has a maximum value of a light absorption spectrum in the vicinity of 315 nm in the form of a film, and becomes insoluble when sensed by light up to 370 nm. . The photosensitive group itself has an ylide structure and is hydrophilic, but it undergoes a transfer reaction upon irradiation with light and changes into a hydrophobic structure.

This product can be obtained, for example, by adding polyvinyl alcohol or partially saponified polyvinyl acetate to the general formula A pyridinium ylide compound represented by or a general formula (Wherein R ¹ and R ² in the formula are each a lower alkyl group or both form an alkylene group), and can be produced by reacting a pyridinium ylide compound.

The pyridinium ylide compound used as this raw material is a novel compound, and examples thereof include 4-formyl-N- (1-pyridinio) benzamidate, 4-dimethoxymethyl-N- (1-pyridinio) benzamidate, and 3-. Dimethoxymethyl-N- (1
-Pyridinio) benzamidate, 4-diethoxymethyl-N
-(1-Pyridinio) benzamidate and the like.

On the other hand, polyvinyl alcohol may partially contain unsaponified acetyl groups, but its content is preferably less than 30% in order to maintain water solubility. The degree of polymerization is 300 to 3000.
It is necessary to choose within the range. In this case, if the degree of polymerization is too low, it will not be sufficiently insolubilized, and if it is too high, the viscosity will increase and this may hinder actual use.

The reaction between the above-mentioned pyridinium ylide compound and polyvinyl alcohol or partially saponified polyvinyl acetate, that is, the polymer acetalization reaction can be carried out in water by an acid-catalyzed reaction. In this case, the amount of the pyridinium ylide compound is 0.1 to 5 mol% per vinyl alcohol unit.
It is preferable to use the ratio of As the acid of the catalyst, any of inorganic organic can be used, and examples thereof include hydrochloric acid, sulfuric acid, phosphoric acid, perchloric acid, methanesulfonic acid, p-toluenesulfonic acid, and acidic ion exchange resins. The addition amount may be 0.01 to 0.5 mol /. Reaction at room temperature for about 1 to 24 hours is sufficient. In this polymer acetalization reaction, the concentration of polyvinyl alcohol is 2 to 20 W / W
The range of% is optimal.

The photosensitive resin thus obtained contains a pyridinium ylide unit in which the resin purified as described in Examples contains a pyridinium ylide unit approximately equal to the charging ratio of the acetalization reaction, and a resin having any pyridinium ylide introduction amount can be easily prepared. It can be synthesized, and the raw material pyridinium ylide compound is hardly wasted. The reaction solution in which the acetalization reaction is completed can be used as a highly sensitive photosensitive solution itself after neutralization. The photoinsolubilization does not depend on the dimerization reaction of the photosensitive group, but is a reaction by a single molecule, so that even if the pyridinium ylide compound remaining in the acetalization reaction is present, it does not hinder the insolubilization of the polymer. If the salt generated by the neutralization of the acid of the catalyst interferes, use an acidic ion exchange resin as the catalyst and remove it by filtration after the reaction is completed, or if a basic ion exchange resin is used to neutralize the acid of the catalyst, salts A photosensitive resin solution containing no is easily obtained. Further, the method using such an ion exchange resin has a simple manufacturing process and is excellent in economical efficiency, and is suitable for an industrial manufacturing method. In order to obtain a further purified resin, after the completion of the reaction, the reaction mixture is poured into a coagulation bath of a large amount of non-solvents such as ethanol, acetone, dioxane to precipitate the desired photosensitive resin, which is then separated. It can be achieved by washing with alcohol. INDUSTRIAL APPLICABILITY The photosensitive resin of the present invention is soluble in water, has an extremely low photointroduction rate, and exhibits a practical photosensitivity without using a sensitizer. This resin of the present invention requires a small amount of photosensitive groups and is very economical. The absorption coefficient of the photosensitive group is about several thousand in the form of a film, and since the insolubilization is due to the monomolecular reaction of the photosensitive group, the reaction efficiency does not decrease due to the progress of the reaction, and it can be sufficiently insolubilized even as a resin film with a large film thickness. it can. Further, since the hydrophilic structure is changed to the hydrophobic structure by photoreaction, swelling by water as a developer is suppressed, and the resolution and the water resistance of the cured film are excellent.

〔The invention's effect〕

The photosensitive resin of the present invention is useful as a printing plate-making material, a non-silver salt image forming material, an aqueous paint base, a vehicle for printing ink, and the like. Furthermore, since the photosensitizing group has a charge-separated ylide structure but has no charge as a whole, it is less likely to harm enzymes, microorganisms, plant cells, and animal cells,
Since the insolubilization reaction also changes itself to a nonionic structure due to the monomolecular reaction of the photosensitive group, there is little risk of damaging those biomaterials at the time of insolubilization, and it is also useful as a material for immobilizing biofunctional materials. is there. Further, since it can be applied to a material having a large film thickness and the cured film has excellent transparency, it can be applied to medical optical materials such as intraocular lenses. On the other hand, considering the adhesive strength of polyvinyl alcohol,
It can also be used for applications such as adhesives and binders that have improved characteristics by light irradiation.

〔Example〕

Next, the present invention will be described in more detail based on Examples and Reference Examples.

Reference Example 1 30 g of 4-formylbenzoic acid, 26 g of 2,2-dimethoxypropane, 100 ml of anhydrous methanol, and 0.2 g of p-toluenesulfonic acid were mixed and stirred overnight to give a colorless solution. Add 0.15g anhydrous potassium carbonate to this solution and add
After stirring for a period of time, the solution was concentrated and crystallized. This was dissolved in diethyl ether, washed with water, and the ether solution was dried over anhydrous magnesium sulfate and concentrated. The precipitated crystals are washed with a mixed solution of ether-hexane (1: 1),
g of 4-dimethoxymethylbenzoic acid was obtained. Melting point 126-127
° C.

Reference Example 2 1.96 g of 4-dimethoxymethylbenzoic acid cooled in an ice bath,
To a solution of 1.2 g of triethylamine and 15 ml of methylene chloride, 1.3 g of thionyl chloride was added dropwise with stirring. After 30 minutes, the ice bath was removed, and the mixture was stirred at room temperature for another hour. This solution was added dropwise to a mixture of 2.22 g of 1-aminopyridinium iodide, 15 ml of methanol, and 5.53 g of anhydrous potassium carbonate while stirring under ice cooling. After stirring overnight, the mixture was concentrated. Dissolve the concentrated residue in water,
It was extracted three times with methylene chloride. The methylene chloride solution was dried over anhydrous magnesium sulfate and concentrated. Crystallization from benzene-cyclohexane gave 1.35 g of 4-dimethoxymethyl-N- (1-pyridinio) benzamidate. 93.
Decomposes at 5 ° C.

Example 1 25% of 1.9 g of completely saponified polyvinyl alcohol having a polymerization degree of 1700
Dissolve in ml water and then 113 mg 4-dimethoxymethyl-N-
(1-Pyridinio) benzamidate was added and dissolved. To this solution, 0.25 ml of concentrated hydrochloric acid was added, and after stirring at room temperature for 24 hours, 0.31 ml of 1 mol / lithium hydroxide solution was added to make the solution slightly alkaline. This solution was poured into a large amount of ethanol little by little, and the resulting precipitate was washed with ethanol and dried. Yield 1.57g. This polymer has shoulder absorption around 300 nm in aqueous solution and has 4-dimethoxymethyl-N- (1-pyridinio)
By using the extinction coefficient of benzamidate, the pyridinium ylide was 0.97 mol% per vinyl alcohol unit. Prepared from an aqueous solution by spin coating,
The film dried at 80 ° C. for 30 minutes had an absorption maximum at 315 nm, and its extinction coefficient was 5.2 × 10 ³ . A negative image was provided by extracting 300-380 nm light with a filter using a 500 W ultra-high pressure mercury lamp and irradiating the film for 30 seconds. Sensitivity measured by changing the exposure time was calculated using ammonium dichromate with a polymerization degree of 1700.
It was about one-eighth as compared with the composition in which 10 W / W% was mixed with polyvinyl alcohol.

Example 2 40 g of 3.3 g of completely saponified polyvinyl alcohol having a degree of polymerization of 1700
Dissolve in 63 ml water and then 631 mg 4-dimethoxymethyl-N-
(1-Pyridinio) benzamidate was added and dissolved.
0.42 ml concentrated hydrochloric acid was added to this solution, and after 24 hours at room temperature, 1 m
It was neutralized by adding 5.5 ml of a lithium hydroxide solution of ol /.
The film prepared from this solution was exposed to light as in Example 1 to give a negative image. The amount of pyridinium ylide introduced into this polymer, which had been purified by precipitation with ethanol, was 3.13 mol% per vinyl alcohol unit.

Claims (3)

[Claims] 1. A general formula A photosensitive resin comprising a polyvinyl alcohol derivative having a structural unit represented by and having a degree of polymerization of 300 to 3000. 2. Polyvinyl alcohol or partially saponified polyvinyl acetate and the general formula A pyridinium ylide compound represented by or a general formula ^2. A pyridinium ylide compound represented by the formula: wherein R ¹ and R ² are each a lower alkyl group or both form an alkylene group. Manufacturing method of photosensitive resin. 3. The method according to claim 2, wherein the pyridinium ylide compound is used in a proportion of 0.1 to 5 mol% based on the vinyl alcohol unit of polyvinyl alcohol or polyvinyl acetate.