JPH08269162A - Production of ultraviolet curing resin - Google Patents

Abstract

PURPOSE: To obtain an ultraviolet curing resin having excellent storage stability, easily developable with a dilute alkali, giving a cured product having excellent heat-resistance, adhesivity and moisture resistance and useful for solder photoresist ink, etc., by simultaneously reacting an epoxy resin with plural dibasic acids having different molecular weights. CONSTITUTION: This ultraviolet curing resin is produced by reacting (A) a novolac-type epoxy resin with (B) an unsaturated monocarboxylic acid and reacting the product simultaneously with (C) a dibasic acid having a molecular weight of <=120 (e.g. succinic anhydride) and (D) a dibasic acid having a molecular weight of >=140 (e.g. tetrahydrophthalic anhydride) at a molar ratio of 3/7 to 7/3. Preferably, the reaction of the component A with the component B is carried out e.g. at 90-200 deg.C and the product is reacted with the components C and D at 60-120 deg.C. The amount of the components C and D is preferably >=0.4mol based on 1mol of the OH group of the reaction product of the components A and B.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing an ultraviolet curable resin. More specifically, the present invention is useful as a photoresist for copper etching when manufacturing a printed wiring board and a photosensitive resin for a solder photoresist ink as a permanent protective film, which has good storage stability and can be developed with dilute alkali. TECHNICAL FIELD The present invention relates to a method for producing an ultraviolet curable resin that gives a cured product having excellent heat resistance, adhesion, and moisture resistance.

[0002]

2. Description of the Related Art At present, a dilute alkali developing type liquid solder photoresist ink is widely used as a solder resist for various printed wiring boards. Examples of such a composition for a solder photoresist ink include a UV curable product obtained by reacting a reaction product of a novolac type epoxy resin and an unsaturated monocarboxylic acid with a saturated or unsaturated polybasic acid anhydride. A first liquid component consisting of a resin, a photopolymerization initiator and a diluent is mixed with a second liquid component consisting of a thermosetting component which is an epoxy resin having two or more epoxy groups in one molecule and a diluent. There is known a two-pack composition used for the above (Japanese Patent Publication No. 1-54390). The composition for a solder photoresist ink obtained by mixing the two liquids is applied to a printed wiring board, the coating surface is made tack-free by a temporary drying step, and then UV exposure is performed using a photomask to dilute the alkali. The unexposed portion is removed by developing with an aqueous solution, and the exposed portion is completely thermoset by heating. The first liquid component of such a solder photoresist ink composition contains a highly reactive unsaturated bond, a carboxyl group, and a photopolymerization initiator in the same liquid, and thus has poor storage stability and a short shelf life. There is a problem. Also,
A compound having an epoxy group is blended as a second liquid component,
When it is used as a two-component resist ink, when the pot life is attempted to be improved, there arises a drawback that properties such as adhesion, water-soluble flux resistance and heat resistance of the resulting coating film are deteriorated. Therefore, the storage stability is good and the shelf life is long, and when the composition for a solder photoresist ink is used, the developability with a dilute alkali is good,
Moreover, an ultraviolet curable resin having excellent mechanical and chemical properties of a cured product is desired.

[0003]

DISCLOSURE OF THE INVENTION The present invention improves the storage stability of conventional UV curable resins for solder photoresist inks, and contains a UV curable resin, a photopolymerization initiator and a diluent. Has a long shelf life, has good dilute alkali developability after exposure, and has excellent adhesion, heat resistance, and moisture resistance of the cured product to the substrate, a method for producing an ultraviolet curable resin for a solder photoresist ink It is made for the purpose of providing.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention reacted two kinds of different molecular weights after reacting an unsaturated monocarboxylic acid with a novolac type epoxy resin. UV curable resin obtained by reacting dibasic acid at the same time provides a composition for solder photoresist ink having excellent storage stability and dilute alkali developability, and the cured product has good mechanical and chemical properties. The present invention has been completed, and the present invention has been completed based on this finding. That is, in the present invention, (1) after reacting a novolac type epoxy resin with an unsaturated monocarboxylic acid, a dibasic acid anhydride having a molecular weight of 120 or less and a dibasic acid anhydride having a molecular weight of 140 or more are mixed at a molar ratio of 3 / 7 to 7/3
The present invention provides a method for producing an ultraviolet-curable resin, which is characterized by reacting simultaneously at a ratio such that Furthermore, in a preferred embodiment of the present invention, (2) a novolac type epoxy resin and an unsaturated monocarboxylic acid are added in an amount of 90 to 200
The method for producing an ultraviolet-curable resin according to item (1), wherein the amount of dibasic acid anhydride reacted with the reaction product of a novolac type epoxy resin and an unsaturated monocarboxylic acid is novolac type. The method for producing an ultraviolet-curable resin according to any one of (1) to (2), wherein the amount of the hydroxyl group contained in the reaction product of the epoxy resin and the unsaturated monocarboxylic acid is 0.4 mol or more, and (4) novolak. The reaction product of the epoxy resin with unsaturated monocarboxylic acid and the dibasic acid anhydride
The method for producing an ultraviolet-curable resin according to items (1) to (3), which reacts at ˜120 ° C., can be mentioned.

The novolac type epoxy resin used in the present invention is a polyfunctional epoxy resin obtained by reacting phenol novolac or cresol novolac which is a reaction product of phenol or o-cresol and formaldehyde with epichlorohydrin. Those having an average number of phenol nuclei of not less than 5 and not more than 7 and an epoxy equivalent of 170 to 230 can be preferably used. When the number of nuclei of the phenol nucleus is less than 5, the cured product of the solder photoresist ink composition may become brittle. When the number of phenol nuclei exceeds 7, the dilute alkali developability and shelf life (storage stability) of the solder photoresist ink composition may decrease. In the present invention, a novolac type epoxy resin is reacted with an unsaturated monocarboxylic acid. The reaction between the epoxy group and the carboxyl group opens the oxirane ring to form a hydroxyl group and an ester bond. The unsaturated monocarboxylic acid used is not particularly limited, and examples thereof include acrylic acid, methacrylic acid, crotonic acid, vinyl acetic acid, sorbic acid, cinnamic acid, etc. Acrylic acid has good photopolymerizability of the product. Since the cured product has excellent properties, it can be used particularly preferably. The reaction method of the novolac type epoxy resin and the unsaturated monocarboxylic acid is not particularly limited, and for example, the novolac type epoxy resin and the unsaturated monocarboxylic acid can be reacted by heating in a suitable diluent. As the diluent, for example, methyl ethyl ketone, ketones such as cyclohexanone, toluene, aromatic hydrocarbons such as xylene, methanol,
Alcohols such as isopropanol and cyclohexanol, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, petroleum-based solvents such as petroleum ether and petroleum naphtha, cellosolves such as cellosolve and butyl cellosolve, and carbitol such as carbitol and butyl carbitol. Examples thereof include acetic acid esters such as talls, ethyl acetate, butyl acetate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, and butyl carbitol acetate.

In the present invention, the amount of epoxy groups in the novolac type epoxy resin and the amount of unsaturated monocarboxylic acid are
It is preferable that the amounts are almost equivalent. If the epoxy group is excessive or the unsaturated monocarboxylic acid is excessive, the storage stability may be deteriorated and the properties of the cured product may be deteriorated. The reaction temperature of the novolac type epoxy resin and the unsaturated monocarboxylic acid is preferably 90 to 200 ° C.,
It is more preferably 100 to 130 ° C. When the novolac type epoxy resin and the unsaturated monocarboxylic acid are reacted, the total amount of the novolac type epoxy resin and the unsaturated monocarboxylic acid in the reaction mixture composed of the novolac type epoxy resin, the unsaturated monocarboxylic acid and the diluent is 20. ~
It is preferably 80% by weight. The reaction product of the novolac type epoxy resin and the unsaturated monocarboxylic acid can be directly subjected to the reaction with the following dibasic acid anhydride as a diluent solution without isolation. In the present invention, a dibasic acid anhydride having a molecular weight of 120 or less and a dibasic acid anhydride having a molecular weight of 140 or more are added to the reaction product of a novolac type epoxy resin and an unsaturated monocarboxylic acid as two dibasic acid. Simultaneous reaction is carried out at a ratio such that the molar ratio of the anhydride is 3/7 to 7/3. As the dibasic acid anhydride, saturated dibasic acid anhydride and unsaturated dibasic acid anhydride can be used. Examples of the dibasic acid anhydride having a molecular weight of 120 or less include succinic anhydride, methylsuccinic anhydride, glutaric anhydride, maleic anhydride, itaconic anhydride, glutaconic anhydride, citraconic anhydride, and diglycolic anhydride. Among these, succinic anhydride can be particularly preferably used. Examples of the dibasic acid anhydride having a molecular weight of 140 or more include allyl succinic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride. Acid, methylendomethylenetetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride, diphenic anhydride,
Examples thereof include nitrophthalic anhydride and phthalonic anhydride. Among these, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride and hexahydrophthalic anhydride can be particularly preferably used.

In the present invention, the dibasic acid anhydride reacts with the hydroxyl group contained in the reaction product of the novolac type epoxy resin and the unsaturated monocarboxylic acid to form an ester bond and a free carboxyl group. The state of the free carboxyl group formed here and the bond of the carboxyl group with the main chain skeleton has a strong influence on the dilute alkali developability, storage stability and properties of the cured coating film, and the molecular weight is 120 or less. By simultaneously reacting the dibasic acid anhydride and the dibasic acid anhydride having a molecular weight of 140 or more at a molar ratio of 3/7 to 7/3, the molar ratio is preferably 4/6 to 6/4. It is possible to obtain an ultraviolet curable resin having good performance by simultaneously reacting at a ratio such that Molecular weight is 12
The molar ratio of the dibasic acid anhydride having a molecular weight of 0 or less to the dibasic acid anhydride having a molecular weight of 140 or more is less than 3/7, and the molecular weight is 120.
When the proportion of the following dibasic acid anhydride is small, the dilute alkali developability may be deteriorated. If the molar ratio of the dibasic acid anhydride having a molecular weight of 120 or less to the dibasic acid anhydride having a molecular weight of 140 or more exceeds 7/3 and the proportion of the dibasic acid anhydride having a molecular weight of 140 or more is small, shelf life and pot The life may be shortened and good physical properties of the coating film may not be sufficiently exhibited. In the present invention, it is important that two kinds of dibasic acid anhydrides having different molecular weights are simultaneously added to the reaction product of the novolac type epoxy resin and the unsaturated monocarboxylic acid to react with each other. The effect of the present invention cannot be obtained when two types of dibasic acid anhydrides are separately reacted with a reaction product of a saturated monocarboxylic acid.
The mechanism is not clear, but by reacting two kinds of dibasic acid anhydrides simultaneously, two or more kinds of chemically different carboxyl groups are generated in the same molecule in the UV curable resin, It is considered that, for the first time, the above performance, which was not possible with the ultraviolet curable resin obtained by reacting a single dibasic acid anhydride, was exhibited.

In the present invention, one type of dibasic acid anhydride having a molecular weight of 120 or less can be used, and two or more types can be used in combination. Similarly, one type of dibasic acid anhydride having a molecular weight of 140 or more can be used, and two or more types can be used in combination. Even if the number of dibasic acid anhydrides used increases, the molar ratio of the dibasic acid anhydride having a molecular weight of 120 or less to the dibasic acid anhydride having a molecular weight of 140 or more is 3
Within the range of / 7 to 7/3, the effect of the present invention can be obtained. In the present invention, the amount of the dibasic acid anhydride reacted with the reaction product of the novolac type epoxy resin and the unsaturated monocarboxylic acid is 1 mol of the hydroxyl group contained in the reaction product of the novolac type epoxy resin and the unsaturated monocarboxylic acid. It is preferably 0.4 mol or more. When the amount of the dibasic acid anhydride to be reacted is less than 0.4 mol per 1 mol of the hydroxyl group contained in the reaction product of the novolac type epoxy resin and the unsaturated monocarboxylic acid, the dilute alkali developability and the coating film properties are improved. It may decrease. In the present invention, the dibasic acid anhydride having a molecular weight of 120 or less and the dibasic acid anhydride having a molecular weight of 140 or more are simultaneously added to and reacted with the reaction product of the novolac type epoxy resin and the unsaturated monocarboxylic acid. When the reaction product of the novolac type epoxy resin and the unsaturated monocarboxylic acid is present as a solution of a diluent,
By adding a mixture of dibasic acid anhydrides to this solution, heating and dissolving it to react, the reaction can be favorably promoted. The reaction temperature of the reaction product of the novolac type epoxy resin and the unsaturated monocarboxylic acid with the dibasic acid anhydride is 6
The temperature is preferably 0 to 120 ° C, more preferably 70 to 90 ° C.

The UV-curable resin obtained by the method of the present invention preferably has an acid value of 45 to 90 mgKOH / g. The acid value of the obtained ultraviolet curable resin can be easily adjusted by appropriately selecting the amount of the dibasic acid anhydride that reacts. Acid value of UV curable resin is 45mg
If it is less than KOH / g, the diluted alkali developability of the resist composition and the adhesiveness and heat resistance of the cured coating film may be deteriorated. When the acid value of the ultraviolet curable resin exceeds 90 mgKOH / g, the electric insulation, heat resistance and moisture resistance of the cured coating film may deteriorate. The ultraviolet curable resin obtained by the method of the present invention can be mixed with a photopolymerization initiator and a diluent and can be suitably used as the first liquid component of the composition for a solder photoresist ink. Examples of the thermosetting resin as the second liquid component include an epoxy resin having two or more epoxy groups in the molecule. Further, in these solder photoresist ink compositions, known fillers such as barium sulfate and silicon oxide, known coloring pigments such as phthalocyanine green, phthalocyanine blue, titanium dioxide and carbon black, defoaming agents and leveling agents. And various known additives such as hydroquinone, hydroquinone monomethyl ether, pyrogallol, and t-butyl catechol.

[0010]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The developability and coating film performance were evaluated by the following methods. (1) Dilute Alkali Developability In the process of manufacturing a printed wiring board for testing, solder photoresist ink was applied and immediately dried at 75 ° C for 30 minutes, and 3 days after temporary drying, after curing by light irradiation. Using a 1 wt% sodium carbonate aqueous solution as a developing solution, the developability when developed by stirring with a stirrer at 20 ° C. for 5 minutes was evaluated according to the following criteria. ◎: Development is possible within 1 minute. ◯: Development is possible in over 1 minute and within 3 minutes. Δ: Development is possible in more than 3 minutes and within 5 minutes. X: Development is impossible within 5 minutes. (2) Adhesion In accordance with JIS K 5400 8.5.2, put 10 crosscuts in a grid pattern on each test printed wiring board, and then peel off the coating film after the peeling test with cellophane tape. The state was visually determined. A: 100/100 with no peeling observed. ◯: 100/100 with a slight line edge. Δ: 90/100 to 99/100. X: 0/100 to 89/100. (3) Pencil hardness According to JIS K 5400 84.2, "Mitsubishi Uni"
The pencil was used for evaluation with the highest hardness without scratching the coating film. (4) Soldering heat resistance Each test printed wiring board was coated with rosin flux [Asahi Chemical Laboratory Co., Ltd., trade name GX-7], and the coating surface was soldered in a solder bath kept at 260 ° C. The film was floated for 15 seconds so that the coating film was swollen and peeled off. This was repeated as one cycle until swelling or peeling occurred, and evaluation was made by the total time until swelling or peeling occurred. (5) Water-soluble flux resistance Water-soluble flux [LONCO, trade name CF-350] was applied to each test printed wiring board, and the coating film surface was brought into contact with the solder in a solder bath at 260 ° C. After floating for 5 seconds and soaking in warm water at 60 ° C. for 15 minutes, a peeling test was performed using cellophane tape. At the same time, the change in gloss on the surface of the coating film, especially the whitening state, was observed. The evaluation criteria are shown below. Peeling test ◎: It does not peel at all. ○: Slightly peeled off. Δ: 10 to 30% of the whole is peeled off. X: 31% or more of the total peeled off. Whitening state ◎: No whitening at all. ○: Only slightly whitened. Δ: 10 to 30% of the whole is whitened. ×: 31% or more of the whole is whitened. (6) Shelf life promotion test of UV curable resin Put the UV curable resin in a plastic bottle with a lid and immerse it in a constant temperature bath at 60 ° C, and the viscosity at 25 ° C reaches 2.5 times the initial viscosity. Alternatively, it was evaluated by the number of days until it exceeded 1,000 poise.

Example 1 1 equipped with a stirrer, reflux condenser, dropping funnel and thermometer
A liter separable flask was charged with 188 g of ethyl carbitol acetate and 215 g of a cresol novolac type epoxy resin having an epoxy equivalent of 215 and having an average of 6 phenol nuclei in one molecule. The mixture was heated to 120 ° C. with stirring, and 72 g (1.0 mol) of acrylic acid was added dropwise from the dropping funnel over 1 hour while maintaining 120 ° C., and the reaction was continued at 120 ° C. for 10 hours. Once the reaction mixture has cooled to room temperature, 25% succinic anhydride
g (0.25 mol) and tetrahydrophthalic anhydride 38
g (0.25 mol) was added, and the mixture was again heated to 80 ° C. and reacted for 3 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain a viscous solution. The heating residue of this solution is 65
% By weight and showed an acid value of 53 mg KOH / g as a solution. This solution is named resin A-1. Resin A-1 55
g, photopolymerization initiator [Ciba Geigy, Irgacure 9
07] 4 g, thermosetting accelerator [Shikoku Kasei Co., Ltd., Cureazole 2MA-OK] 0.5 g, trimethylolpropane triacrylate 5 g as a diluent, phthalocyanine green pigment 3 g, barium sulfate 12 g, silicon oxide 1
0 g and defoaming agent [Nippon Kagaku Co., Ltd., Folexlex SO
L-30] 0.5 g was kneaded by a roll mill (three rolls) to prepare a first liquid of a composition for a solder photoresist ink. In addition, epoxy resin [Toto Kasei Co., Ltd.,
YDCN-702S] 8 g and glycerin diglycidyl ether 7 g were mixed to prepare a second liquid of the composition for solder photoresist ink. The first liquid and the second liquid are mixed, and a copper printed wiring board on which a pattern is formed by etching in advance is screen-printed with 15 to 15
It is coated on the entire surface with a film thickness of 20 μm, and is dried in a hot air circulation type drying oven
It was temporarily dried at 5 ° C for 30 minutes. Immediately after the temporary drying, a photomask was applied to the substrate and irradiated with ultraviolet rays of 500 mJ / cm ² by a 3 kW metal halide lamp to perform photo-curing. Then, a 1 wt% sodium carbonate aqueous solution was used as a developing solution to remove the uncured portion of the coating film. The developed substrate is 1 more
Thermal curing was performed at 50 ° C. for 30 minutes to complete a test printed wiring board. With respect to this test printed wiring board, the performance of the coating film was evaluated. The results are shown in Table 1. A shelf life promotion test was conducted on resin A-1. The results are shown in Table 1. Example 2 188 g of butyl cellosolve was used instead of 188 g of ethyl carbitol acetate of Example 1, and 30 g (0.3 mol) of succinic anhydride and methyl tetrahydrophthalic anhydride were used instead of 25 g of succinic anhydride and 38 g of tetrahydrophthalic anhydride. The same operation as in Example 1 was repeated except that 33 g (0.2 mol) of acid was used. The heating residue of the obtained viscous solution was 65% by weight, and
An acid value of mgKOH / g was shown. This solution is named resin A-2. Instead of using 55 g of resin A-1, resin A-2
A test printed wiring board was prepared in the same manner as in Example 1 except that 55 g was used and the performance of the coating film was evaluated. The results are shown in Table 1. A shelf life promotion test was conducted on the resin A-2. The results are shown in Table 1. Example 3 1 equipped with a stirrer, reflux condenser, dropping funnel and thermometer
A liter separable flask was charged with 196 g of ethyl carbitol acetate and 215 g of cresol novolac type epoxy resin having an epoxy equivalent of 215 and having an average of 6 phenol nuclei in one molecule. The mixture was heated to 120 ° C. with stirring, 86 g (1.0 mol) of methacrylic acid was added dropwise from the dropping funnel over 1 hour while maintaining 120 ° C., and the reaction was continued at 120 ° C. for 10 hours.
Once the reaction mixture has cooled to room temperature, succinic anhydride 1
0 g (0.1 mol), 23 g (0.2 mol) of glutaric anhydride and 30 g (0.2 mol) of tetrahydrophthalic anhydride were added, and the mixture was again heated to 80 ° C. and reacted for 3 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain a viscous solution. The heating residue of this solution was 65% by weight,
The solution had an acid value of 52 mg KOH / g. This solution is named resin A-3. 55 g of resin A-3, 3 g of a photopolymerization initiator [Ciba Geigy, Irgacure 907],
Photopolymerization initiator [Nippon Kayaku Co., CAYACURE DE
TX-S] 1 g, thermal curing accelerator [Shikoku Kasei Co., Ltd., Cureazole 2MA-OK] 0.5 g, trimethylolpropane triacrylate 5 g as a diluent, phthalocyanine green pigment 3 g, barium sulfate 12 g, silicon oxide 10 g and 0.5 g of defoaming agent [Nippon Kagaku Co., Ltd., Folexlex SOL-30] was roll milled (3 rolls).
Was kneaded to prepare a first liquid of the composition for solder photoresist ink. Also, a second liquid of a composition for a solder photoresist ink was prepared by mixing 10 g of an epoxy resin [Okaka Shell Epoxy Co., Ltd., Epicoat 828], 3 g of trimethylolpropane triglycidyl ether and 5 g of cellosolve acetate. The first liquid and the second liquid are mixed, and the copper printed wiring board on which a pattern is formed by etching in advance is screen-printed
It was applied to the entire surface in a film thickness of 5 to 20 μm, and temporarily dried at 75 ° C. for 30 minutes in a hot air circulation type drying furnace. Immediately after the temporary drying, a photomask was applied to the substrate and irradiated with ultraviolet rays of 500 mJ / cm ² by a 3 kW metal halide lamp to perform photo-curing. Then, a 1 wt% sodium carbonate aqueous solution was used as a developing solution to remove the uncured portion of the coating film. The developed substrate was further thermally cured at 150 ° C. for 30 minutes to complete a test printed wiring board. With respect to this test printed wiring board, the performance of the coating film was evaluated. The results are shown in Table 1. A shelf life promotion test was conducted on Resin A-3. The results are shown in Table 1.

Comparative Example 1 The amount of ethyl carbitol acetate of Example 1 was 181
g, and the same operation as in Example 1 was repeated except that 50 g (0.5 mol) of succinic anhydride was used instead of 25 g of succinic anhydride and 38 g of tetrahydrophthalic anhydride. The heating residue of the obtained viscous solution was 65% by weight, and the solution had an acid value of 55 mgKOH / g. This solution is named resin B-1. A test printed wiring board was prepared in the same manner as in Example 1 except that 55 g of Resin B-1 was used instead of 55 g of Resin A-1, and the performance of the coating film was evaluated. The results are shown in Table 1. Resin B-
A shelf life promotion test was conducted on No. 1. The results are shown in Table 1. Comparative Example 2 The amount of ethyl carbitol acetate of Example 1 was changed to 204
g of tetrahydrophthalic anhydride instead of 25 g of succinic anhydride and 38 g of tetrahydrophthalic anhydride.
The same operation as in Example 1 was repeated except that g (0.6 mol) was used. The viscous solution thus obtained had a heating residue of 65% by weight and showed an acid value of 59 mgKOH / g as a solution. This solution is named resin B-2. Resin A-1 55
g, instead of using 55 g of resin B-2,
A test printed wiring board was prepared in the same manner as in Example 1, and the performance of the coating film was evaluated. The results are shown in Table 1. A shelf life promotion test was conducted on Resin B-2. The results are shown in Table 1. Comparative Example 3 Resin B-1 and Resin B-2 were mixed at a weight ratio of 1: 1. The heating residue of the resulting viscous solution was 65% by weight and showed an acid value of 57 mg KOH / g as a solution. This solution is named resin B-3. Instead of using 55 g of Resin A-1,
A test printed wiring board was prepared in the same manner as in Example 1 except that 55 g of the resin B-3 was used, and the performance of the coating film was evaluated. The results are shown in Table 1. A shelf life promotion test was conducted on Resin B-3. The results are shown in Table 1. Comparative Example 4 The amount of ethyl carbitol acetate of Example 1 was 191.
g, and instead of 25 g of succinic anhydride and 38 g of tetrahydrophthalic anhydride, 45 g of succinic anhydride (0.45
Mole) and 23 g of tetrahydrophthalic anhydride (0.15
The same operation as in Example 1 was repeated, except that the same amount was used. The viscous solution thus obtained had a heating residue of 65% by weight and showed an acid value of 62 mgKOH / g as a solution. This solution is named resin B-4. A test printed wiring board was prepared in the same manner as in Example 1 except that 55 g of the resin B-4 was used instead of 55 g of the resin A-1, and the performance of the coating film was evaluated. The results are shown in Table 1. Resin B-4
The shelf life promotion test was carried out. First result
Shown in the table.

[0013]

[Table 1]

A composition for a solder photoresist ink using the ultraviolet curable resin produced by the method of the present invention is
The dilute alkali developability is good, the performance of the coating film is excellent in adhesion, pencil hardness, solder heat resistance, and the water-soluble flux resistance is also generally good. On the other hand, in Comparative Example 1 in which only succinic anhydride having a molecular weight of 100 was used as the dibasic acid anhydride, the adhesion was slightly inferior and the solder heat resistance was inferior. In Comparative Example 2 in which only tetrahydrophthalic anhydride having a molecular weight of 152 was used as the dibasic acid anhydride, almost all the performances including the developability were inferior. Comparative Example 3 is an example of using an ultraviolet curable resin in which a resin obtained by reacting succinic anhydride as a dibasic acid and a resin obtained by reacting tetrahydrophthalic anhydride are used, and a succinic anhydride component and tetrahydroanhydride are contained in the resin. Although the phthalic acid component is present in a molar ratio of 48/52, it is 2
Performance is generally inferior because the dibasic acid anhydrides of the species are not simultaneously reacted. In Comparative Example 4, the molar ratio of succinic anhydride and tetrahydrophthalic anhydride used was 75.
/ 25, which is also inferior in overall performance. Further, in the shelf life acceleration test, all of the ultraviolet curable resins A-1 to A-3 according to the method of the present invention showed excellent storage stability, while the resin B-obtained in Comparative Examples 1, 3 and 4
Each of Nos. 1, 3 and 4 thickened in a short time and was inferior in storage stability.

[0015]

The UV curable resin according to the method of the present invention is excellent in storage stability and has good dilute alkali developability when used in a composition for a solder photoresist ink. Excellent heat resistance and moisture resistance.

Claims (1)

[Claims] 1. A novolac type epoxy resin is reacted with an unsaturated monocarboxylic acid, and then a dibasic acid anhydride having a molecular weight of 120 or less and a dibasic acid anhydride having a molecular weight of 140 or more are mixed at a molar ratio of 3/7 to 7. A method for producing an ultraviolet curable resin, which comprises reacting simultaneously at a ratio of / 3.