JPH10274849A - Solder photoresist ink composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable development with a dilute aq. alkali soln. and to improve bendability, soldering resistance, adhesion and chemical resistance by incorporating a specified UV-curing resin, a diluent, etc. SOLUTION: This solder photoresist ink compsn. contains a UV-curing resin, a diluent, a photopolymn. initiator and epoxy resin. The UV-curing resin is obtd. as follows; cresol-novolak type epoxy resin having 65-95 deg.C softening point and epoxy equiv. of 180-230 is mixed with bisphenol A type epoxy resin represented by the formula in a weight ratio of 4:6 to 9:1, the resultant mixture is allowed to react with unsatd. monocarboxylic acid and it is allowed to react further with a dibasic acid anhydride. In the formula, R is H or 2,3-epoxypropyl, at least one of R's in one molecule is 2,3-epoxypropyl and (m) is 1-10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a solder photoresist ink composition. More specifically, the present invention provides a cured coating film having a liquid form of a composition, which can be developed with a dilute aqueous alkali solution, and which has excellent flexibility, solder heat resistance, adhesion, and chemical resistance. The present invention relates to a solder photoresist ink composition suitable for manufacturing a substrate.

[0002]

2. Description of the Related Art In recent years, in the field of printed wiring board processing,
Photocurable compositions are often used as solder photoresist inks, and liquid resist ink compositions have been used as types of solder photoresist inks. For example, JP-A-61-243869 discloses a photocurable liquid resist ink composition which can be developed with a dilute alkali solution, which comprises a reaction product of a novolak type epoxy compound and an unsaturated monocarboxylic acid, and a polybasic acid. A composition comprising an active energy ray-curable resin obtained by reacting with an anhydride, a photopolymerization initiator and a diluent is disclosed. Although this resist ink is excellent in heat resistance, it has a problem that cracks are apt to occur and it is brittle. On the other hand, Japanese Patent Application Laid-Open No. Hei 7-207211 discloses, as a resist ink composition for a flexible printed wiring board, an addition product of a bisphenol A type epoxy resin having three or more epoxy groups and an unsaturated group-containing monocarboxylic acid. A composition comprising an unsaturated group-containing polycarboxylic acid resin which is a reaction product with succinic anhydride, a photopolymerization initiator, a diluent and a curing component is disclosed. Although this resist ink composition is excellent in flexibility, it has a problem that heat resistance is inferior and cannot be used as a solder photoresist ink.

[0003]

DISCLOSURE OF THE INVENTION The present invention relates to a cured coating film which is in a liquid form, can be developed with a dilute aqueous alkali solution, and has excellent flexibility, solder heat resistance, adhesion, chemical resistance and the like. The purpose of the present invention is to provide a solder photoresist ink composition particularly suitable for manufacturing a printed wiring board.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that a mixture of a cresol novolak-type epoxy resin and a bisphenol A-type epoxy resin can contain an unsaturated monocarboxylic acid. A solder photoresist ink composition containing an ultraviolet curable resin, a diluent, a photopolymerization initiator, and an epoxy resin obtained by reacting and further reacting a dibasic acid anhydride has excellent flexibility and solder heat resistance. The present inventors have found that a cured film excellent in the above properties can be provided, and have completed the present invention based on this finding. That is, the present invention provides (1) a softening point of 65 to 95;
° C and an epoxy equivalent of 180 to 230, and 4/6 to 9/1 of a bisphenol A type epoxy resin represented by the general formula [1].
(Weight ratio), characterized in that the mixture contains an ultraviolet curable resin, a diluent, a photopolymerization initiator and an epoxy resin obtained by reacting an unsaturated monocarboxylic acid and further reacting a dibasic acid anhydride. Solder photoresist ink composition,

Embedded image (However, in the formula, R is hydrogen or a 2,3-epoxypropyl group, at least one R in the molecule is a 2,3-epoxypropyl group, and m is 1 to 10.) 3.) The solder photoresist ink composition according to claim 1, wherein the amount of the unsaturated monocarboxylic acid reacted with the epoxy resin mixture is 0.9 to 1.2 mol per equivalent of epoxy group. The amount of the dibasic anhydride to be reacted with the reaction product of the mixture and the unsaturated monocarboxylic acid is 0.4 to 1.0 mole times the unsaturated monocarboxylic acid reacted with the epoxy resin mixture. The solder photoresist ink composition according to 1) or 2), and
(4) The acid value of the ultraviolet curable resin is 40 to 100 mgKOH.
/ G, the solder photoresist ink composition according to the above (1), (2) or (3).

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, the softening point is 65.
A cresol novolak type epoxy resin having an epoxy equivalent of 180 to 230 at ９５95 ° C. is used. Such a cresol novolak type epoxy resin is, for example, o-cresol, m-cresol, p-cresol or any mixture thereof, and a cresol novolak resin obtained from formaldehyde, dissolved in an excess of epichlorohydrin, and heated under heating. After reacting by adding an aqueous sodium hydroxide solution to remove water and epichlorohydrin out of the system, an organic solvent and water are added, and sodium chloride is transferred to an aqueous phase, whereby the compound can be obtained from the organic solvent phase. Such a cresol novolak-type epoxy resin has a structure represented by the general formula [2] as a main structure.

Embedded image In the general formula [2], n is usually 3 to 10. The cresol novolak epoxy resin used in the present invention is preferably an o-cresol novolak epoxy resin. If the softening point of the cresol novolak type epoxy resin is less than 65 ° C., the cured coating film may have insufficient solder heat resistance. When the softening point of the cresol novolak type epoxy resin exceeds 95 ° C., the reaction of the unsaturated monocarboxylic acid and the reaction of the dibasic anhydride with the epoxy resin mixture may not proceed smoothly. If the epoxy equivalent of the cresol novolak type epoxy resin is less than 180, the flexibility of the cured coating film may be insufficient.
If the epoxy equivalent of the cresol novolac type epoxy resin exceeds 230, the cured coating film may have insufficient solder heat resistance and adhesiveness. The softening point of the epoxy resin is J
It can be measured according to IS K 7234.
The epoxy equivalent of the epoxy resin can be measured according to JIS K7236.

In the present invention, a bisphenol A type epoxy resin represented by the general formula [1] is used.

Embedded image In the general formula [1], R is hydrogen or a 2,3-epoxypropyl group, and at least one R in the molecule is 2,2.
A 3-epoxypropyl group, and m is 1 to 10.
Such a bisphenol A type epoxy resin is a bisphenol A wherein R is all hydrogen in the general formula [1].
For example, it can be obtained by reacting epichlorohydrin with a type epoxy resin in the presence of sodium hydroxide. The bisphenol A type epoxy resin used in the present invention preferably has a softening point of 55 to 70 ° C. The bisphenol A type epoxy resin used in the present invention preferably has an epoxy equivalent of 200 to 450, and more preferably 270 to 370.
In the present invention, the mixing ratio of the cresol novolak type epoxy resin having a softening point of 65 to 95 ° C. and an epoxy equivalent of 180 to 230 and the bisphenol A type epoxy resin represented by the general formula [1] is 4 / 6 to 9/1 (weight ratio). If the amount of the cresol novolac type epoxy resin is small and the mixing ratio is less than 4/6 (weight ratio), the solder heat resistance of the cured coating film may be reduced.
If the amount of the bisphenol A type epoxy resin is small and the mixing ratio exceeds 9/1 (weight ratio), the flexibility of the cured coating film may be reduced.

In the present invention, the above-mentioned epoxy resin mixture is reacted with an unsaturated monocarboxylic acid. By reacting the epoxy resin with the unsaturated monocarboxylic acid, the oxirane ring is opened to form a hydroxyl group and an ester bond. There is no particular limitation on the unsaturated monocarboxylic acid used, for example, acrylic acid, methacrylic acid, crotonic acid,
Examples thereof include vinyl acetic acid, sorbic acid, and cinnamic acid. Among them, acrylic acid can be used particularly preferably because it has good reactivity with epoxy groups and the resulting resin has excellent ultraviolet curability. In the present invention, one kind of the unsaturated monocarboxylic acid can be used alone, or two or more kinds can be used in combination. The method for reacting the epoxy resin mixture with the unsaturated monocarboxylic acid is not particularly limited. For example, the reaction can be performed by heating the epoxy resin mixture and the unsaturated monocarboxylic acid in a suitable reaction diluent. As the reaction diluent, an organic solvent or a photopolymerizable monomer can be used. As the organic solvent used as the reaction diluent, for example, methyl ethyl ketone, ketones such as cyclohexanone, toluene, aromatic hydrocarbons such as xylene,
Alcohols such as methanol, isopropanol and cyclohexanol; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; petroleum solvents such as petroleum ether and petroleum naphtha; cellosolves such as cellosolve and butyl cellosolve; carbitol and butyl carbitol Such as carbitols, ethyl acetate, butyl acetate, cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, carbitol acetate,
Acetates such as butyl carbitol acetate can be exemplified. Among these, petroleum solvents and acetates can be particularly preferably used. As the photopolymerizable monomer used as a reaction diluent, for example, methyl (meth) acrylate, ethyl (meth)
Acrylate, n-propyl (meth) acrylate, n-
Butyl (meth) acrylate, 2-ethylhexyl (meth)
Acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, phenoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-butoxyethyl
(Meth) acrylate, glycidyl (meth) acrylate,
2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, benzyl (meth) acrylate, ethylene glycol mono (meth) acrylate, monofunctional acrylate compounds such as ethyl carbitol (meth) acrylate, ethylene glycol di ( (Meth) acrylate, polyethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate,
Trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) Examples include acrylates and polyfunctional acrylates such as polyfunctional epoxy acrylates. In the present invention, one kind of the reaction diluent can be used alone, or two or more kinds can be used in combination. In the present invention, the reaction diluent is preferably added in an amount of 20 to 50% by weight based on the total weight of the reaction system.

In the present invention, a mixture of a cresol novolak type epoxy resin having a softening point of 65 to 95 ° C. and an epoxy equivalent of 180 to 230 and a bisphenol A type epoxy resin represented by the general formula [1] is reacted. The amount of the unsaturated monocarboxylic acid to be used is preferably 0.9 to 1.2 mol, more preferably 1.0 to 1.1 mol, per equivalent of epoxy group in the epoxy resin mixture,
More preferably, it is 1.0 to 1.05 mol. When the amount of the unsaturated monocarboxylic acid to be reacted with the epoxy resin mixture is less than 0.9 mole per equivalent of epoxy group, an undesired reaction is caused in the subsequent synthesis,
There is a possibility that the resin gels. When the amount of the unsaturated monocarboxylic acid to be reacted with the epoxy resin mixture exceeds 1.2 mol per equivalent of epoxy group, an excess carboxyl group remains and a low molecular weight monocarboxylic acid is contained in the resin. As a result, the properties of the cured coating film may be reduced. In the present invention, the reaction temperature between the epoxy resin mixture and the unsaturated monocarboxylic acid is 100 to 120.
C. is preferred. When the reaction temperature is lower than 100 ° C., the reaction rate is low, and the reaction may take a long time. If the reaction temperature exceeds 120 ° C., the unsaturated monocarboxylic acid undergoes thermal polymerization, which may cause gelation during the reaction. In the present invention, in the reaction of the epoxy resin mixture with the unsaturated monocarboxylic acid, triethylamine, benzyldimethylamine, methyltriethylammonium chloride, benzyltrimethylammonium bromide, benzyltrimethylammonium iodide, triphenylphosphine, triphenylstibine, octane Catalysts such as chromic acid and zirconium octoate can be used. The amount of the catalyst used is preferably 0.1 to 10% by weight based on the reaction raw material mixture. Further, in order to prevent polymerization during the reaction, it is preferable to use a polymerization inhibitor such as hydroquinone monomethyl ether, catechol or pyrogallol. The amount of the polymerization inhibitor to be used ranges from 0.01 to
It is preferably 1% by weight.

In the present invention, the reaction product of the epoxy resin mixture and the unsaturated monocarboxylic acid is further reacted with a dibasic acid anhydride. The reaction product of the epoxy resin mixture and the unsaturated monocarboxylic acid can be subjected to a reaction with a dibasic acid anhydride without isolation, as a reaction diluent solution. The dibasic acid anhydride to be reacted is not particularly limited, and either a saturated dibasic acid anhydride or an unsaturated dibasic acid anhydride can be used. Examples of dibasic acid anhydrides include, for example, succinic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, endmethylenetetrahydrophthalic anhydride, methylendo Examples thereof include methylenetetrahydrophthalic anhydride and methylbutenyltetrahydrophthalic anhydride. Among these, succinic anhydride, phthalic anhydride,
Tetrahydrophthalic anhydride and methyltetrahydrophthalic anhydride can be used particularly preferably. In the present invention, one type of dibasic acid anhydride may be used alone, or two or more types may be used in combination.

[0010] The dibasic acid anhydride reacts with the hydroxyl group of the reaction product of the epoxy resin mixture and the unsaturated monocarboxylic acid to form an ester bond and a free carboxyl group. The amount of the dibasic acid anhydride to be reacted is from 0.4 mol of the unsaturated monocarboxylic acid reacted to the epoxy resin mixture.
It is preferably 1.0 mole times. In the epoxy resin mixture, an equivalent number of hydroxyl groups equal to the number of moles of the reacted unsaturated monocarboxylic acid is generated, and in addition, the hydroxyl groups originally contained in the epoxy resin are present. 0.4 moles of unsaturated monocarboxylic acid reacted with the epoxy resin mixture
By reacting 1.0 mole times of the dibasic acid anhydride, a part of the hydroxyl groups of the resin can be left as it is, and the remaining hydroxyl groups can be esterified. If the amount of the dibasic acid anhydride to be reacted is less than 0.4 mole times the unsaturated monocarboxylic acid reacted with the epoxy resin mixture, the diluted alkali developability of the solder photoresist ink composition may be reduced. is there. If the amount of the dibasic acid anhydride to be reacted exceeds 1.0 mole times the unsaturated monocarboxylic acid reacted with the epoxy resin mixture, the storage stability of the solder photoresist ink composition may be reduced.
In the present invention, the dibasic acid anhydride is added to the reaction product of the epoxy resin mixture and the unsaturated monocarboxylic acid to cause a reaction. If the reaction product is present as a solution of the reaction diluent, dissolve by adding dibasic anhydride to this solution;
By heating, the reaction can proceed. The reaction temperature is preferably from 70C to 100C. The ultraviolet curable resin obtained by further reacting the reaction product of the epoxy resin mixture and the unsaturated monocarboxylic acid with a dibasic acid anhydride preferably has an acid value of 40 to 100 mgKOH / g, and preferably 55 to 85 mgKOH. / G is more preferable. The acid value of the ultraviolet curable resin can be easily adjusted by appropriately selecting the amount of the dibasic acid anhydride that reacts. UV curable resin has an acid value of 40mgKOH /
If the amount is less than g, the diluted alkali developability of the solder photoresist ink composition may be reduced. If the acid value of the ultraviolet curable resin exceeds 100 mgKOH / g, the chemical resistance of the cured coating film may be reduced.

In the present invention, a diluent, a photopolymerization initiator and an epoxy resin are added to the ultraviolet-curable resin thus obtained to obtain a solder photoresist ink composition. In the present invention, a photopolymerizable monomer or an organic solvent can be used as the diluent. As a photopolymerizable monomer that can be used as a diluent, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n- propyl (meth) acrylate, n- butyl
(Meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, phenoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-butoxy Ethyl (meth) acrylate, glycidyl (meth) acrylate, 2
-Hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, benzyl (meth) acrylate, ethylene glycol mono (meth) acrylate,
Monofunctional acrylate compounds such as ethyl carbitol (meth) acrylate, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylol Multifunctional such as propane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, polyfunctional epoxy acrylates Acrylate and the like can be mentioned. Examples of the organic solvent that can be used as a diluent include, for example, methyl ethyl ketone, ketones such as cyclohexanone, aromatic hydrocarbons such as toluene and xylene, methanol, isopropanol, alcohols such as cyclohexanol, cyclohexane, and methylcyclohexane. Petroleum solvents such as alicyclic hydrocarbons, petroleum ether, petroleum naphtha, cellosolves such as cellosolve and butyl cellosolve, carbitols such as carbitol and butyl carbitol, ethyl acetate, butyl acetate, cellosolve acetate, ethyl cellosolve Acetates such as acetate, butyl cellosolve acetate, carbitol acetate, butyl carbitol acetate and the like can be mentioned. Among these, petroleum solvents and acetates can be particularly preferably used. In the present invention, one of these diluents can be used alone, or two or more thereof can be used in combination. When the diluent is a photopolymerizable monomer, the photopolymerizable monomer plays a role of diluting the solder photoresist ink composition and adjusting the viscosity to be easily applied, and also a role of promoting photopolymerization. When the diluent is an organic solvent, the organic solvent plays a role of diluting the solder photoresist ink composition, adjusting the viscosity to be easily applied, applying the composition to a printed wiring board, and then drying the composition to form a film. In the present invention, a reaction diluent is used during the reaction between the epoxy resin mixture and the unsaturated monocarboxylic acid and dibasic anhydride,
When the reaction diluent is present in the solution of the ultraviolet curable resin, the reaction diluent can be used as it is as a diluent. Further, if necessary, a new diluent can be added in addition to the reaction diluent present in the solution of the ultraviolet curable resin. In the solder photoresist ink composition of the present invention, the content of the diluent is preferably 30 to 200 parts by weight per 100 parts by weight of the ultraviolet curable resin.

In the present invention, the photopolymerization initiator is not particularly limited as long as it absorbs ultraviolet rays to induce polymerization. Examples thereof include benzoins such as benzoin and benzoin methyl ether, acetophenone and 2,2-dimethoxy. -2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexylphenylketone, N, N-dimethylaminoacetophenone, 2-methyl-1- [4- (methylthio Acetophenones such as) phenyl] -2-morpholinopropan-1-one;
Methylanthraquinone, 2-ethylanthraquinone, 1
-Chloroanthraquinone, 2-amylanthraquinone,
Anthraquinones such as 2-aminoanthraquinone,
Thioxanthones such as 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropylthioxanthone and 2-isopropylthioxanthone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenone; methyl Benzophenone, 4,4'-
Benzophenones such as dichlorobenzophenone and 4,4′-bisdiethylaminobenzophenone can be mentioned. Among them, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-
A combination of ON with 2,4-diethylthioxanthone can be suitably used. One of these photopolymerization initiators can be used alone, or two or more can be used in combination. The amount of the photopolymerization initiator is preferably 2 to 30 parts by weight, more preferably 3 to 20 parts by weight, per 100 parts by weight of the ultraviolet curable resin in the solder photoresist ink composition.

The epoxy resin contained in the solder photoresist ink composition of the present invention is not particularly limited. Examples thereof include bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol AD epoxy resin, phenol novolak epoxy resin, Cresol novolak type epoxy resin, cycloaliphatic epoxy resin,
Glycidyl ester resin, glycidylamine resin,
Heterocyclic ester resins and the like can be mentioned. As such an epoxy resin, for example, Yuka Shell Co., Ltd.
Epicoat 1007, Epicoat 1009, Epicoat 1031, Dow Chemical Co., Ltd., DER-642
U, bisphenol A type epoxy resin such as DER-673MF, manufactured by Toto Kasei Co., Ltd., YDF-2004, YDF
-2007 and other bisphenol F type epoxy resins, manufactured by Nippon Kayaku Co., Ltd., EPPN-201, EOCN-102
Novolak-type epoxy resins such as S, EOCN-103S and EOCN-1020, bisphenol A having three or more epoxy groups in one molecule represented by the general formula [1]
And a type epoxy resin. Among these, novolak-type epoxy resins such as EOCN-103S and EOCN-1020 can be particularly preferably used. The epoxy resin is used in the solder photoresist ink composition in an amount of 4 to 3 per 100 parts by weight of the ultraviolet curable resin.
It is preferably 0 parts by weight, more preferably 7 to 20 parts by weight. Barium sulfate, barium titanate, the solder photoresist ink composition of the present invention,
Inorganic fillers such as silicon oxide and amorphous silica can be blended. The amount of the inorganic filler is preferably 0.1 to 50% by weight, more preferably 5 to 30% by weight in the solder photoresist ink composition. The solder photoresist ink composition of the present invention further includes, if necessary, a coloring pigment such as phthalocyanine green, phthalocyanine blue, iodine green, crystal violet, or titanium oxide, or a silicone-based or fluorine-based antifoaming agent. Additives can be blended. In preparing the solder photoresist ink composition of the present invention, it is preferable to uniformly mix the components using a roll mill or the like.

[0014]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. In addition, the solder photoresist ink composition was evaluated by the following method. (1) Flexibility The solder photoresist ink composition is applied to the entire surface of the aluminum foil so that the film thickness becomes 200 μm.
After temporarily drying at 80 ° C for 60 minutes in a hot-air circulation drying oven,
UV light 500mJ / cm by KW metal halide lamp
Irradiate ² and light cure. 2cm from the obtained plate
A test piece of × 1 cm is cut out, and a shallow cut is made on the surface of the coating film with a cutter blade at the center of the test piece parallel to the side of 1 cm in length. The test piece is bent at the position of the back surface of the cut, and the bending angle when the coating film breaks is measured. The greater the bending angle when the coating film breaks, the better the flexibility. (2) Solder heat resistance The solder photoresist ink composition is coated on a copper foil substrate by a screen printing method to have a coating thickness of 15 μm to 20 μm.
And then temporarily dried at 80 ° C. for 20 minutes in a hot-air circulating drying oven. Then, a negative film having a resist pattern is applied, and ultraviolet light of 500 mJ / cm ² is irradiated by a 3 KW metal halide lamp to perform photocuring. . Next, the uncured portion of the coating film is removed using a 1% by weight aqueous solution of sodium carbonate as a developing solution, and then thermally cured at 150 ° C. for 30 minutes in a hot-air circulation drying oven to prepare an evaluation substrate. A rosin-based flux is applied to this evaluation substrate,
Float for 15 seconds in a solder bath at 60 ° C. so that the resist coating contacts the solder. The resist film is checked for damage such as peeling or swelling, and this cycle is repeated every 15 seconds until the resist film is damaged. The accumulated time up to the cycle before the damage of the resist coating occurs,
Solder heat resistance. (3) Adhesion An evaluation board was prepared in the same way as solder heat resistance, and JIS
In accordance with K 5400 8.5.2, cuts that penetrate the coating film on the evaluation board and reach the bare ground are made in a grid pattern with a clearance of 1 mm, and an adhesive tape is peeled off on the grid. The state of adhesion of the coating film after the coating is visually observed. (4) Chemical resistance A flux for a leveler was applied to an evaluation substrate prepared by the same method as that for soldering heat resistance, and was placed in a 260 ° C. solder bath.
After immersion for 2 seconds, immersion in warm water of 60 ° C. for 30 minutes, drying, and visually observing the appearance of the coating film. Furthermore, an adhesive tape is peeled off from the coating film, and the adhered state of the coating film after peeling is visually observed. Synthesis Example 1 (Synthesis of bisphenol A type epoxy resin represented by general formula [1]) In a 3 liter flask, a bisphenol A type epoxy resin having an epoxy equivalent of 560 and a softening point of 78 ° C [oiled shell epoxy ( KK, Epicoat 1002] 530 g,
1,480 g of epichlorohydrin and 500 g of dimethyl sulfoxide were charged and heated to 70 ° C. with stirring to form a uniform solution. Then, 50 g of a 48% by weight aqueous sodium hydroxide solution was added dropwise over 60 minutes, and further reacted at 70 ° C. for 3 hours. Was done. Next, unreacted epichlorohydrin and dimethylsulfoxide were distilled off under reduced pressure, and 800 g of methyl isobutyl ketone and water 2 were added to the obtained reaction product.
After adding and stirring 00 g, the aqueous phase was separated after standing still. Further, after repeating the same washing operation twice by adding 200 g of water, methyl isobutyl ketone was distilled off from the methyl isobutyl ketone phase to obtain a bisphenol A type epoxy resin a having an epoxy equivalent of 331 and a softening point of 66 ° C. I got Synthesis Example 2 (Synthesis of bisphenol A type epoxy resin represented by general formula [1])
g of bisphenol A having an epoxy equivalent of 310 and a softening point of 60 ° C.
A type epoxy resin b was obtained. Production Example 1 (Production of UV-curable resin) In a 1-liter separable flask, 153.4 g of ethyl carbitol acetate, an epoxy equivalent of 214,
Cresol novolak type epoxy resin having a softening point of 84 ° C. [Nippon Kayaku Co., Ltd., EOCN-103S] 171.2 g,
42.8 g of bisphenol A epoxy resin a having an epoxy equivalent of 331 and a softening point of 66 ° C., and 67.9 acrylic acid
g, triethylamine 2 g, and hydroquinone monomethyl ether 0.5 g. The mixture was heated to 110 ° C. with stirring, and the reaction was continued for 20 hours while maintaining 110 ° C.
Once the reaction was cooled to room temperature, succinic anhydride 21.
7 g, 33.0 g of tetrahydrophthalic anhydride and 30.7 g of ethyl carbitol acetate were added, and the mixture was heated at 100 ° C. and reacted for 5 hours to obtain an ultraviolet curable resin solution A.
The acid value of this ultraviolet curable resin was 72 mgKOH / g. Production Example 2 (Production of UV-curable resin) In a 1-liter separable flask, 157.8 g of ethyl carbitol acetate, an epoxy equivalent of 216,
Cresole novolak type epoxy resin having a softening point of 90 ° C. [Nippon Kayaku Co., Ltd., EOCN-104S] 159.8 g,
64.2 g of bisphenol A type epoxy resin b having an epoxy equivalent of 310 and a softening point of 60 ° C., 69.1 acrylic acid
g, triethylamine 2 g, and hydroquinone monomethyl ether 0.5 g. The mixture was heated to 110 ° C. with stirring, and the reaction was continued for 20 hours while maintaining 110 ° C.
Once the reaction was cooled to room temperature, succinic anhydride 47.
3 g and 25.5 g of ethyl carbitol acetate were added, and the mixture was heated to 100 ° C. and reacted for 5 hours to obtain an ultraviolet-curable resin solution B. The acid value of this UV-curable resin is 78 mg
KOH / g. Production Example 3 (Production of Ultraviolet-Curable Resin) In a 500-ml separable flask, 138.1 g of ethyl carbitol acetate, an epoxy equivalent of 212, and a softening point of cresol novolac epoxy resin having a softening point of 70 ° C. [Nippon Kayaku Co., Ltd. , EOCN-102S] 137.3 g,
58.9 g of bisphenol A epoxy resin a having an epoxy equivalent of 331 and a softening point of 66 ° C., and acrylic acid 60.3
g, triethylamine 2 g, and hydroquinone monomethyl ether 0.5 g. The mixture was heated to 110 ° C. with stirring, and the reaction was continued for 20 hours while maintaining 110 ° C.
Once the reaction was cooled to room temperature, 63.6 g of tetrahydrophthalic anhydride, 33.6 g of ethyl carbitol acetate.
8 g was added, and the mixture was heated to 100 ° C. and reacted for 5 hours to obtain an ultraviolet-curable resin solution C. The acid value of this ultraviolet curable resin was 73 mgKOH / g. Production Example 4 (Production of Ultraviolet-Curable Resin) In a 500-ml separable flask, 136.3 g of ethyl carbitol acetate, an epoxy equivalent of 214, and a softening point of 84 ° C. cresol novolac epoxy resin [Nippon Kayaku Co., Ltd. , EOCN-103S] 98.1 g, an epoxy equivalent of 331, a softening point of 668.1C bisphenol A type epoxy resin a 98.1 g, acrylic acid 54.5 g,
2 g of triethylamine and 0.5 g of hydroquinone monomethyl ether were charged. The mixture was heated to 110 ° C. with stirring, and the reaction was continued for 20 hours while maintaining 110 ° C. Once the reaction was cooled to room temperature, succinic anhydride 16.9
g, 25.7 g of tetrahydrophthalic anhydride and 23.9 g of ethyl carbitol acetate, and the mixture was heated to 100 ° C. and reacted for 5 hours to obtain an ultraviolet curable resin solution D. The acid value of this ultraviolet curable resin was 65 mgKOH / g. Production Example 5 (Production of UV-curable resin) In a 1-liter separable flask, 265.7 g of ethyl carbitol acetate, an epoxy equivalent of 214,
Cresin novolak type epoxy resin having a softening point of 84 ° C. [Nippon Kayaku Co., Ltd., EOCN-103S] 363.8 g,
124.2 g of acrylic acid, 2 g of triethylamine and 0.5 g of hydroquinone monomethyl ether were charged. Heat to 110 ° C with stirring, and keep at 110 ° C for 2 hours.
The reaction was continued for 0 hours. Once the reaction was cooled to room temperature, 42.5 g of succinic anhydride, 64.6 g of tetrahydrophthalic anhydride, 57.7 g of ethyl carbitol acetate
Was added, and the mixture was heated to 100 ° C. and reacted for 5 hours to obtain an ultraviolet-curable resin solution E. The acid value of this UV-curable resin is
It was 80 mgKOH / g. Production Example 6 (Production of UV-curable resin) Bisphenol A-type epoxy resin a21 having 142.3 g of ethyl carbitol acetate, an epoxy equivalent of 331 and a softening point of 66 ° C was placed in a 500-ml separable flask.
5.2 g, acrylic acid 47.0 g, triethylamine 2
g of hydroquinone monomethyl ether. The mixture was heated to 110 ° C. with stirring, and the reaction was continued for 20 hours while maintaining 110 ° C. Once the reaction was cooled to room temperature, 16.3 g of succinic anhydride, 24.7 g of tetrahydrophthalic anhydride, ethyl carbitol acetate 2
After adding 2.1 g, the mixture was heated to 100 ° C. and reacted for 5 hours to obtain an ultraviolet-curable resin solution F. The acid value of this ultraviolet curable resin was 60 mgKOH / g. Example 1 UV curable resin solution A20.0 synthesized in Production Example 1
g, dipentaerythritol hexaacrylate 1.0
g, photopolymerization initiator [Irgacure 907, Ciba-Geigy] 1.5 g, photopolymerization initiator [Kayacure DETX-
S, Nippon Kayaku Co., Ltd.] 0.5 g, barium sulfate 6.0 g, antifoaming agent [Formlex SOL-30, Nichika Chemical Co., Ltd.]
0.3 g and 0.5 g of a phthalocyanine green pigment were kneaded using a roll mill, and the epoxy equivalent was 214;
2.3 g of a solution prepared by diluting a cresol novolak type epoxy resin having a softening point of 84 ° C. [EOCN-103S, Nippon Kayaku Co., Ltd.] to 65% by weight with ethyl carbitol acetate.
The resulting mixture was mixed to prepare a solder photoresist ink composition. In the bending test, the bending angle when the coating film was broken was 33 ^° . In the solder heat resistance test of the solder photoresist ink composition, the coating film was not damaged even after repeating 5 cycles. In the adhesion test,
Each of the cuts was thin and smooth at both ends, and the intersection of the cuts and the square did not peel off at a glance. In the chemical resistance test, there was no abnormality such as swelling in the coating film after drying, and no peeling occurred in the coating film even after the adhesive tape was peeled off. Example 2 A solder photoresist ink composition was prepared in the same manner as in Example 1 except that the ultraviolet-curable resin solution B synthesized in Production Example 2 was used instead of the ultraviolet-curable resin solution A. In the bending test, the bending angle when the coating film broke was 36 ^o.
Met. In the solder heat resistance test of the solder photoresist ink composition, the coating film was not damaged even after repeating 5 cycles. In the adhesion test, each cut was thin and the both ends were smooth, and the intersection of the cut and the square did not peel off at every glance. In the chemical resistance test, there was no abnormality such as swelling in the coating film after drying, and no peeling occurred in the coating film even after the adhesive tape was peeled off. Example 3 A solder photoresist ink composition was prepared in the same manner as in Example 1, except that the ultraviolet curable resin solution C synthesized in Production Example 3 was used instead of the ultraviolet curable resin solution A. In the bending test, the bending angle when the coating film broke was 38 ^o
Met. In the solder heat resistance test of the solder photoresist ink composition, the coating film was not damaged even after repeating 5 cycles. In the adhesion test, each cut was thin and the both ends were smooth, and the intersection of the cut and the square did not peel off at every glance. In the chemical resistance test, there was no abnormality such as swelling in the coating film after drying, and no peeling occurred in the coating film even after the adhesive tape was peeled off. Example 4 A solder photoresist ink composition was prepared in the same manner as in Example 1 except that the ultraviolet-curable resin solution D synthesized in Production Example 4 was used instead of the ultraviolet-curable resin solution A. In the bending test, the bending angle when the coating film was broken was 43 ^°.
Met. In the solder heat resistance test of the solder photoresist ink composition, even after repeating 4 cycles, the coating film was not damaged, but after the fifth cycle, a small blister was generated in the coating film. In the adhesion test, cut 1
Each book was thin and smooth at both ends, and there was no separation at the intersection of the cut and the square. In the chemical resistance test,
There was no abnormality such as swelling in the dried coating film, and no peeling occurred in the coating film even after the adhesive tape was peeled off. Comparative Example 1 A solder photoresist ink composition was prepared in the same manner as in Example 1, except that the ultraviolet curable resin solution E synthesized in Production Example 5 was used instead of the ultraviolet curable resin solution A. In the bending test, the bending angle when the coating film broke was 16 ^o.
Met. In the solder heat resistance test of the solder photoresist ink composition, the coating film was not damaged even after repeating 5 cycles. In the adhesion test, there was no peeling of each square at a glance, but there was slight peeling at the intersection of the cuts. In the chemical resistance test, there was no abnormality such as swelling in the coating film after drying, and no peeling occurred in the coating film even after the adhesive tape was peeled off. Comparative Example 2 A solder photoresist ink composition was prepared in the same manner as in Example 1, except that the ultraviolet curable resin solution F synthesized in Production Example 6 was used instead of the ultraviolet curable resin solution A. In the bending test, the bending angle when the coating film broke was 47 ^°
Met. In the solder heat resistance test of the solder photoresist ink composition, the coating film was not damaged in the first cycle, but the coating film was swollen after the second cycle. In the adhesion test, each of the cuts was thin and the both ends were smooth, and the intersection of the cut and the square did not peel off at every glance. In the chemical resistance test, there was no abnormality such as swelling in the coating film after drying, and no peeling occurred in the coating film even after the adhesive tape was peeled off. Table 1 shows the results of Examples 1 to 4 and Comparative Examples 1 and 2.

[0015]

[Table 1]

The cured coating films obtained from the solder photoresist ink compositions of the present invention of Examples 1 to 4 have good flexibility, and are excellent in all of solder heat resistance, adhesion and chemical resistance. On the other hand, the cured coating film obtained from the solder photoresist ink composition of Comparative Example 1 using a UV-curable resin synthesized using only the cresol novolak type epoxy resin as a raw material has inferior flexibility. Further, the cured coating film obtained from the solder photoresist ink composition of Comparative Example 2 using a UV-curable resin synthesized using only the bisphenol A type epoxy resin as a raw material has remarkably inferior solder heat resistance.

[0017]

The cured coating film obtained from the solder photoresist ink composition of the present invention is excellent in flexibility, solder heat resistance, adhesion, and chemical resistance.
It can be suitably used as a solder photoresist for a printed wiring board.

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Claims (4)

[Claims] 1. A cresol novolak type epoxy resin having a softening point of 65 to 95 ° C. and an epoxy equivalent of 180 to 230, and bisphenol A represented by the general formula [1].
UV-curable resin obtained by reacting an unsaturated monocarboxylic acid with a mixture of 4/6 to 9/1 (weight ratio) of epoxy resin, and further reacting with a dibasic acid anhydride, a diluent, and a photopolymerization initiator And a solder photoresist ink composition containing an epoxy resin. Embedded image (However, in the formula, R is hydrogen or a 2,3-epoxypropyl group, at least one R in the molecule is a 2,3-epoxypropyl group, and m is 1 to 10.) 2. The amount of the unsaturated monocarboxylic acid to be reacted with the epoxy resin mixture is 0.9 to 0.9 per equivalent of epoxy group.
2. The solder photoresist ink composition according to claim 1, wherein the amount is 1.2 mol. 3. The amount of a dibasic acid anhydride reacted with a reaction product of an epoxy resin mixture and an unsaturated monocarboxylic acid is as follows:
3. The solder photoresist ink composition according to claim 1, wherein the amount of the unsaturated monocarboxylic acid reacted with the epoxy resin mixture is 0.4 to 1.0 mol times. 4. An ultraviolet-curable resin having an acid value of 40 to 100.
4. The solder photoresist ink composition according to claim 1, wherein the composition is mgKOH / g.