JPS6341923B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for purifying an aqueous solution of a photosensitive resin, particularly an aqueous solution of a polyvinyl alcohol derivative containing a stilbazolium group or a styrylquinolinium group. Background of the Technology Photosensitive resin is a material that hardens or becomes insoluble when exposed to light, and is generally used for printing plate materials such as letterpress, lithographic, flat intaglio, and gravure plates, or for metal corrosion processing in the production of printed substrates, integrated circuits, name plates, etc. Widely used in photoresists. Furthermore, photosensitive resins are also widely put into practical use for forming image-forming films on substrates such as films, glass plates, screens, or fabrics. Photosensitive resins having photosensitive residues such as azide groups, cinnamoyl groups, and acryloyl groups have been known so far. These resins do not necessarily have satisfactory sensitivity, and many of them are insoluble in water. Therefore, when an organic solvent or an alkaline aqueous solution is used as a solvent, there are inconveniences in handling during coating and developing steps. On the other hand, as water-soluble photosensitive resins, compositions of aqueous resins such as polyvinyl alcohol, gelatin, glue, and dichromate or diazonium salts are known. Among these water-soluble photosensitive resin compositions, compositions containing dichromate have poor stability and storage stability of the aqueous solution and film formed by coating, and also have poor stability and storage stability due to hexavalent chromium in the treatment of waste liquid. However, it has been difficult to put dichromate-containing photosensitive resin compositions into practical use. In addition, in the case of photosensitive resin compositions containing diazonium salts, the stability and storage stability are better than those containing dichromate, but they are not satisfactory.
In particular, its sensitivity is inferior to that of dichromate-containing photosensitive resins, and the strength of the cured film obtained by exposure is also insufficient. In order to solve the above-mentioned problems of water-soluble photosensitive resins, a photo-insolubilizable resin which is a polyvinyl alcohol derivative containing a stilbazolium group and a method for producing the same were published in Japanese Patent Publication No. 56-5761 and Japanese Patent Publication No. 56-56.
-Disclosed in No. 5762. Similarly, a photoinsolubilizable polyvinyl alcohol derivative containing a styrylquinolinium group and a method for producing the same were disclosed in JP-A-56-
No. 11906. Although these photosensitive stilbazolium group- or styrylquinolinium group-containing polyvinyl alcohol derivatives have excellent sensitivity and water solubility, they have the following problems. According to the above-mentioned patent, in order to apply the photo-insolubilizable resin as a solution onto the printing plate, the photo-insolubilizable resin is prepared by acetalization or acetal exchange reaction, and then the reaction solution is poured into a large amount of an insoluble solvent such as acetone. The solid content is recovered once, washed with a solvent, dried, and then dissolved in water to be used as an aqueous solution. Such a method uses a large amount of solvent, which complicates the process and requires extra equipment. Furthermore, problems of fire and pollution may arise. It is also said that the photo-insolubilized resin can be used as it is without being recovered as a solid content from the reaction solution, but in that case the sensitivity will be lower than when it is purified. Furthermore, according to the comparative study results of the present inventors, when the reaction solution is applied to the plate material as it is acidic or after being neutralized with a base, inorganic acids and inorganic salts as catalysts are present in the plate material. The adhesion between the photocured film and the plate material becomes extremely poor. Purpose of the Invention The purpose of the present invention is to provide a photosensitive material that eliminates the complexity of the process as described above, and also allows a polyvinyl alcohol-based reaction solution to be used as it is as a photoinsolubilizable resin aqueous solution without causing the problem of decreased sensitivity. An object of the present invention is to provide a method for purifying an aqueous resin solution. Structure of the Invention The present invention provides that after the completion of an acetalization reaction or an acetal exchange reaction in a polyvinyl alcohol system,
The reaction product is purified with an ion exchange resin, and the polyvinyl alcohol-based reaction solution is used as it is as a photo-insolubilized resin aqueous solution, and the photo-insolubilized resin is precipitated from this reaction solution and recovered and purified as a solid content. This method omitted the step of redissolving to form a solution, and even if this reaction solution was used directly, it could show the same sensitivity as that obtained by precipitation and purification without causing a decrease in sensitivity. be. That is, the present invention is based on the general formula () or () (In the formula, R ₁ and R ₂ represent a hydrogen atom and an alkyl group, respectively, Y represents a conjugate base of an acid, and m is 1 to
is an integer of 6, and n is 0 or 1. ) Acetalization reaction between polyvinyl alcohol or modified polyvinyl alcohol and a compound having a stilbazolium group or styrylquinolinium group to produce a polyvinyl alcohol derivative containing a stilbazolium group or a styrylquinolinium group as a photosensitive unit; Provided is a method for purifying an aqueous photosensitive resin solution, which comprises carrying out an acetal exchange reaction and then treating the resulting reaction mixture with an ion exchange resin. The acetalization reaction to polyvinyl alcohol in the present invention is performed with polyvinyl alcohol and the following general formula () or (). (In the formula, R ₁ represents a hydrogen atom, an alkyl group, an aralkyl group, a hydroxyl group, a carbamoyl group,
May contain ether bonds and unsaturated bonds, R ₂
represents a hydrogen atom or a lower alkyl group, and X represents a halogen ion, a phosphate ion, a sulfate ion, a methosulfate ion, a p-toluenesulfonate ion, or a mixture thereof. ) is reacted with a styrylpyridinium or styrylquinolinium compound in water using an acid as a catalyst. In addition, the acetal exchange reaction to polyvinyl alcohol is performed using polyvinyl alcohol and the following general formula () or (). (In the formula, R ₁ represents a hydrogen atom, an alkyl group, an aralkyl group, a hydroxyl group, a carbamoyl group,
May contain ether bonds and unsaturated bonds, R ₂
represents a hydrogen atom or a lower alkyl group, X represents an anionic residue of a strong acid, R ₃ and R ₄ are each an alkyl group or both form an alkylene group, and n is 1 to 6. is an integer. ) is reacted with a styrylpyridinium or styrylquinolinium compound in water using an acid as a catalyst. When the polyvinyl alcohol-based reaction solution obtained by the acetalization reaction or acetal exchange reaction is made into an aqueous solution for plate coating by leaving it acidic or just neutralizing it with a base, the acetalization reaction or acetal exchange reaction is an equilibrium reaction, (1) there is unreacted styrylpyridinium or styrylquinolinium, (2) there is a salt of the catalyst due to neutralization with the catalyst acid or base, and (3) there are various reactions. Ionic impurities (for example, dimer compounds produced as by-products during the production of compounds of formula () or ()).
If it is applied to a substrate in this state, all of these substances will be included in the coating film. These substances are considered to have an adverse effect on the photosensitivity of the coating film and the film strength after development, as shown in the Examples and Comparative Examples below. Therefore, in the present invention, ion exchange treatment is performed, and the method will be described. The pH of the polyvinyl alcohol reaction solution treated with an anion exchange resin is 4 or more, preferably 5 to 7.
shall be. As a result, the acid radicals of the catalytic acid are supplemented by the anion exchange resin, and OH ^- is released instead, so that the pH of the reaction solution increases. Then, by applying a predetermined amount of a cation exchange resin, the unreacted compound of the general formula, or, and the dimer compound corresponding to or can be removed.
If the pH is likely to drop below 4 due to the action of the cation exchange resin, the action of the anion exchange resin must be added immediately. This is because both the acetalization reaction and the acetal exchange reaction are equilibrium reactions, so if the unreacted photosensitive groups are removed while the reaction solution is acidic, the photosensitive groups attached to the saponified polyvinyl acetate will dissociate. It is. Also, for this reason, it is necessary to apply the ion exchange resin to the reaction solution first by applying the anion exchange resin and then by applying the cation exchange resin. In addition, when an ion exchange resin is used, especially when unreacted photosensitive compounds are removed using a cation exchange resin, the problem is that the partially saponified polyvinyl alcohol with which the photosensitive groups have reacted is also adsorbed to the ion exchange resin. However, as a result of detailed research by the present inventors, it has been found that there is no problem with this point. That is, although the cation exchange resin had an adsorption effect on photosensitive compounds and dimers, it did not have an adsorption effect on cationic polymers to which photosensitive compounds were added. In the present invention, the method of making the ion exchange resin act is by adding the ion exchange resin into the polyvinyl alcohol reaction solution, or by filling a column with the ion exchange resin and flowing the reaction solution through the column. good. Also, an ion exchange membrane may be used instead of the ion exchange resin. Furthermore, the polyvinyl alcohol-based reaction solution in the present invention can be used as it is acidic, but
If the solution is left in an acidic state, the viscosity of the solution gradually increases, and as a result, it tends to become gel-like with no fluidity. Therefore, in order to keep the viscosity of the solution stable, it is necessary to adjust the pH of the solution to 4 or more, preferably 5 to 8. The present invention will be explained in more detail below using examples. Reference Example 1 200 mg (0.6 milliequivalent) of N-methyl-γ-(p-formylstyryl)pyridinium methosulfate was dissolved in 400 c.c. of distilled water. The electrical conductivity and pH of this solution were 104 μ/cm and 5.80, respectively. The distilled water had an electrical conductivity of 1.3 μ/cm and a pH of 5.82. Add 2 H-type strongly acidic cation exchange resin (Mitsubishi Diaion SK1B: 1.2 meq/ml) to this solution.
After adding 4 ml of OH type strong basic anion exchange resin (Mitsubishi Diaion SA10A: 0.6 meq/ml) and stirring for 10 minutes, the conductivity of the solution was 2.0 μ/ml.
cm, and pH was 5.05. That is, it was found that by using an ion exchange resin (by using 4 times the equivalent amount of resin), the quaternary salt was almost completely adsorbed and removed. Reference Example 2 231 mg (0.6 milliequivalent) of N-methyl-4-(p-formylstyryl)quinolinium methosulfate was dissolved in 400 c.c. of distilled water. The electrical conductivity of this solution was 96 μ/cm, and the pH was 6.10. Distilled water had an electrical conductivity of 1.3 μ/cm and a pH of 5.82. The same ion exchange resin as in Reference Example 1 was added to this solution and stirred. The electrical conductivity of the solution was 1.8 μ/cm and the pH was 5.00. Reference Example 3 247 mg (0.6 milliequivalent) of N-methyl-2-{p-(2,2-dimethoxyethoxy)styryl}pyridinium methosulfate was dissolved in 400 c.c. of distilled water. After this solution was treated with an ion exchange resin in the same manner as in Reference Example 1, the solution exhibited almost the same conductivity and pH as distilled water. Reference Example 4 Dissolve 200 g of partially saponified polyvinyl alcohol with a degree of polymerization of 1700 (degree of saponification 88%) in 2000 c.c. of water, and then dissolve 30 g of N-methyl-γ-(p-formylstyryl) pyridinium methosulfate. was added and dissolved. Add 8g of 85% phosphoric acid to this solution,
After reacting at 60°C for 3 hours, it was left at room temperature overnight. Next, this solution was dropped into a large amount of acetone, and the resulting precipitate was decanted and washed twice with acetone. The mixture was further stirred for 30 minutes in ethanol containing a small amount of ammonia, and washed with methanol. Vacuum dry this to obtain approximately 200 solids.
I got g. The addition rate of SBQ in this product is 1.49 mol%
It was hot. 4.5 g of this solid was dissolved in 400 c.c. of water. Approximately 1.5 milliequivalents of pyridinium salt are added to this. After adding 20ml of strongly basic anion exchange resin to this solution, strongly acidic cation exchange resin
After adding 100 ml and stirring thoroughly, the ion exchange resin was removed by filtration. When the quaternary salt concentration of this solution was measured using an ultraviolet-visible spectrophotometer, it was found to be almost the same as before ion exchange.
In other words, it was found that the quaternary salt added to the polymer was not adsorbed by the ion exchange resin even if 80 times the equivalent of the ion exchange resin was used. Example 1 200 g of partially saponified polyvinyl alcohol with a degree of polymerization of 2000 (degree of saponification 88%) was dissolved in 1800 c.c. of water, and then 20 g of N-methyl-γ-(p-formylstyryl) pyridinium monomethyl sulfate was dissolved. was added and dissolved. Add 6g of 85% phosphoric acid to this solution and
After reacting at °C for 5 hours, it was left at room temperature overnight. 1000 g of this solution was collected, and 100 ml of a strongly basic anion exchange resin was added thereto to adjust the pH to 6.4.
When 50 ml of cation exchange resin was added to this solution and thoroughly stirred, the pH became 6.1. The ion exchange resin was removed through this process to obtain 900 g of a solution. The number of moles of photosensitive groups added to this product was 1.01 mol%. This solution was diluted three times with water and then coated on a glass plate to a thickness of 1 micron using a spin coater. This was irradiated for 30 seconds from a distance of 1 meter under a 2kW ultra-high pressure mercury lamp, and a clear negative image was obtained. At the same time, I checked the sensitivity of Kodak Step Tablet No. 2, but at this time, 8 steps remained solid. Comparative Example 1 The solution of Example 1 before the ion exchange treatment was left at room temperature overnight, and then neutralized with 28% aqueous ammonia. This was diluted three times with water and then coated on a glass plate to a thickness of 1 micron using a spin coater. A negative image was obtained by irradiating this under a 2kW ultra-high pressure mercury lamp from a distance of 1 meter for 30 seconds, but the adhesion to the glass plate was poor and the image was slightly wrinkled. Also, only 6 solid steps remained on the Kodak step tablet that was printed at the same time. Examples 2 to 11 and Comparative Examples 2 to 11 After treating the solutions listed in Table 1 with an ion exchange resin in the same manner as in Example 1, spin coating and exposure development were performed on a glass plate in the same manner as in Examples 2 to 11. Obtained. Further, Comparative Examples 2 to 11 were carried out in the same manner as Comparative Example 1 using the solutions listed in Table 2. Table 1 shows each result.
Shown in Table 2. In Tables 1 and 2, the examples with each number correspond to the comparative examples with the same number.

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Claims (1)

[Claims] 1 General formula () or () (In the formula, R ₁ and R ₂ represent a hydrogen atom and an alkyl group, respectively, Y represents a conjugate base of an acid, and m is 1 to
is an integer of 6, and n is 0 or 1. ) Acetal of polyvinyl alcohol or modified polyvinyl alcohol and a compound having a styrylbazolium group or a styrylquinolinium group to produce a polyvinyl alcohol derivative containing a styrylbazolium group or a styrylquinolinium group as a photosensitive unit. 1. A method for purifying an aqueous photosensitive resin solution, which comprises carrying out a chemical reaction or an acetal exchange reaction, and then treating the resulting reaction mixture with an ion exchange resin.