JP2894460B2 - Solder resist ink composition and cured product thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solder resist ink composition having excellent heat resistance, electrical insulation, adhesion, moisture resistance, chemical resistance, high heat deformation temperature and hardness and low bleed, and a cured product thereof. .

[0002]

2. Description of the Related Art Solder resist inks are usually used on circuit boards (eg, paper-phenol, paper-epoxy, glass-).
By etching a copper-clad laminate using an organic material such as epoxy as a base material, a printed circuit board obtained by forming a desired circuit, or using a ceramic or other inorganic material as a base material,
A circuit board obtained by forming a desired circuit by a screen printing method using a conductor or a resistor, etc.), and forming a protective coating film by screen printing or roll coating on the surface of the electric and moisture-resistant circuit. It is used for protection, protection of circuit at the time of soldering, protection of substrate in plating process, etc.
6408, JP-A-51-87028 and JP-A-54-87028.
156167, JP-A-55-12175, JP-A-5-12
5-53478, JP-A-55-46165, JP-A-61-12772 and JP-A-63-30578.

As a solder resist, a bisphenol A type epoxy resin, a phenol novolak type epoxy resin or a cresol novolak type epoxy resin mixed with a curing agent has been used.

[0004]

In recent years, miniaturization and high-density of circuit boards have been advanced, and with this, the required characteristics of solder resists have become more sophisticated, and the heat distortion temperature has been increased.
There is a demand for one having excellent dimensional stability, heat resistance, high electrical insulation, moisture resistance, and the like.

[0005]

SUMMARY OF THE INVENTION The present invention provides a solder having a low heat distortion temperature, excellent heat resistance, electrical insulation, adhesion, hardness, moisture resistance, chemical resistance, plating resistance, etc., and low bleed. A resist ink composition and a cured product thereof are provided. That is, the present invention provides: Equation (1)

[0006]

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(Wherein R ₁ and R ₂ are the same or different and each represents a residue of a compound having two or more phenolic hydroxyl groups from which the hydroxyl group has been removed. Z ₁ and Z ₂ are the same or different and are 0 or 1 And the sum of Z ₁ and Z ₂ is 1 or more, M is a glycidyl group or a hydrogen atom, and n is an integer of 1 or more, provided that when n is 1, M is always glycidyl. And when n is 2 or more, at least one of M is a glycidyl group.) A solder resist ink composition comprising the epoxy resin (A).

[0008] 2. A solder resist ink composition comprising the epoxy resin (A), the curing agent (B), and the solvent (C) according to claim 1. 3. 3. The solder resist ink composition according to claim 2, wherein the curing agent (B) is one or more selected from the group consisting of dicyandiamide, imidazole compounds, triazine compounds, urea compounds, aromatic amine compounds, and cationic photopolymerization catalysts. 4. Solvent (C) is the formula (2)

[0009]

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Wherein R ₁ is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, R ₂ is an ethylene group which may be substituted by a methyl group, R ₃ is a hydrogen atom or

[0011]

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Wherein R ₄ represents an alkyl group having 1 to 8 carbon atoms. However, R ₁ and R ₃ are not hydrogen atoms at the same time. n shows the integer of 1-4. 4.) The solder resist ink composition according to item 2 or 3, which is one kind or two or more kinds selected from the group consisting of a compound represented by the formula (1) and solvent naphtha, Item 5 relates to a cured product of the solder resist ink composition according to item 1, item 2, item 3 or item 4.

Specific examples of the epoxy resin represented by the formula (1) include R ₁ and R ₂ in the formula (1).
Represents a residue of a compound having three or more phenolic hydroxyl groups, from which the hydroxyl group has been removed, represented by the formula

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[0026] (wherein, P is 0 or 1 or more represents an integer.) As an indication of R ₁ and R ₂ hydroxyl group is removed residue of a compound having two phenolic hydroxyl groups of the formula

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The following are examples, but the present invention is not limited to these. Further, R ₁ and R ₂ in the formula (1) may include different values. The epoxy resin of the formula (1) is obtained by, for example,

[0068]

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(Wherein R ₁ , R ₂ and Z ₁ , Z ₂ and n
Has the same meaning as in formula (1). )) Can be obtained by reacting an alcoholic hydroxyl group with epichlorohydrin.

The reaction between the alcoholic hydroxyl group of the epoxy resin represented by the formula (3) and epichlorohydrin can be carried out in the presence of an alkali metal hydroxide by using, for example, dimethyl sulfoxide or a quaternary ammonium salt. At that time, alcohols, aromatic monovalent hydrogens, ketones, cyclic and ether compounds, etc. may be used in combination. Unless dimethyl sulfoxide or a quaternary ammonium salt is used, the reaction does not proceed sufficiently, and a large amount of alkali metal hydroxide remains, causing polymerization and it is difficult to produce the epoxy resin of the present invention.

The amount of dimethyl sulfoxide used is determined by the formula (3)
Is preferably 5% by weight to 300% by weight with respect to the epoxy resin represented by the formula: When the content is 5% by weight or less with respect to the epoxy resin represented by the formula (3), the reaction between the alcoholic hydroxyl group of the epoxy resin represented by the formula (3) and epichlorohydrin becomes slow, so that a long-time reaction is required. Not preferred.
300% by weight based on the epoxy resin represented by the formula (3)
When it exceeds, the effect of increasing the amount is almost negligible, but the volumetric efficiency becomes poor, which is not preferable.

Examples of the quaternary ammonium salt include tetramethylammonium chloride, tetramethylammonium bromide, and trimethylbenzylammonium chloride. The amount of the quaternary ammonium salt is based on 1 equivalent of the alcoholic hydroxyl group of the epoxy resin represented by the formula (3). 0.3-5
0 g is preferred. If the amount is less than 0.3 g per 1 equivalent of the hydroxyl group, the reaction between the alcoholic hydroxyl group of the epoxy resin represented by the formula (3) and epichlorohydrin becomes slow, and a long-time reaction is required, which is not preferable. If it exceeds 50 g with respect to 1 equivalent of hydroxyl group, the effect of increasing the amount is almost negligible, but the cost increases, which is not preferable.

The amount of epichlorohydrin used may be at least equivalent to one equivalent of the alcoholic hydroxyl group to be epoxidized of the epoxy resin represented by the general formula (3). However, if the equivalent is more than 30 equivalents to 1 equivalent of the hydroxyl group, the effect of increasing the amount is almost negligible, but the volumetric efficiency deteriorates, which is not preferable.

As the alkali metal hydroxide, caustic soda in which caustic soda, caustic potash, lithium hydroxide, calcium hydroxide and the like can be used is preferable. The amount of the alkali metal hydroxide used may be approximately equivalent to 1 equivalent of the alcoholic hydroxyl group to be epoxidized in the epoxy resin represented by the general formula (3). When the alcoholic hydroxyl groups of the epoxy resin represented by the formula (3) are totally epoxidized, the alcoholic hydroxyl groups may be used in excess. Tends to happen. The alkali metal hydroxide may be a solid or an aqueous solution. When an aqueous solution is used, the reaction can be carried out while distilling water out of the reaction system under normal pressure and reduced pressure during the reaction.

The reaction temperature is preferably from 30 to 100 ° C. When the reaction temperature is lower than 30 ° C., the reaction becomes slow and a long-time reaction is required. If the reaction temperature exceeds 100 ° C., many side reactions occur, which is not preferable.

After completion of the reaction, excess epichlorohydrin and dimethyl sulfoxide are distilled off under reduced pressure, and then the resin is dissolved in an organic solvent, and a dehydrohalogenation reaction can be performed with an alkali metal hydroxide. On the other hand, after completion of the reaction, the product is washed with water and separated to separate a by-product salt and dimethyl sulfoxide or a quaternary ammonium salt. Excess epichlorohydrin is distilled off from the oil layer under reduced pressure, and then the resin is dissolved in an organic solvent to prepare an alkali metal hydroxide. To carry out a dehydrohalogenation reaction. As the organic solvent, methyl isobutyl ketone, benzene, toluene, xylene and the like can be used,
Methyl isobutyl ketone is preferred. They can be used alone or in a mixed system.

Examples of the curing agent (B) include dicyandiamide and imidazole compounds (for example, 2-ethyl-4
-Methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 2,4-diamino-6
(2-methylimidazolyl- (1))-ethyl-S-triazine, 2,4-diamino-6- (2-ethyl-4-
Methylimidazolyl- (1))-ethyl-S-triazine / isocyanuric acid adduct, 2-methyl-imidazole, 1-phenyl-2-methyl-imidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, etc.) , Triazine compounds (for example, 2,4-diamino-6-vinyl-S-triazine-isocyanuric acid adduct, 2-vinyl-4,6-diamino-S-triazine,
2-methoxyethyl-4,6-diamino-S-triazine, 2-0-cyanophenyl-4,6-diamino-S-
Triazine, etc.), urea compounds (for example, 3- (3,4
-Dichlorophenyl) -1,1'-dimethylurea;
1,1′-isophorone-bis (3-methyl-3-hydroxyethylurea), 1,1′-tolylene-bis (3,
3-dimethylurea), an aromatic amino compound (eg, 4,4′-diamino-diphenylmethane, etc.) and a cationic photopolymerization catalyst (eg, triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluorophosphate, triphenylsulfonium) Hexafluoroantimonate, triphenylselenium hexafluorophosphate, triphenylselenium hexafluoroantimonate, diphenyliodonium hexafluoroantimonate, diphenyliodonium hexafluorophosphate, 2,4-cyclopentadien-1-yl) [(1-methylethyl )-
Benzene] -Fe-hexafluorophosphate (Irgacure 261 manufactured by Ciba-Geigy Corporation) and the like.

Among the curing agents (B), particularly preferred are dicyandiamide, 2,4-diamino-6
[2'-Methylimidazolyl (1) ']-ethyl-S-
Triazine, 2-ethyl-4-methylimidazole,
1,1′-isophorone-bis (3-methyl-3-hydroxyethylurea), 1,1′-tolylene-bis (3,
3-dimethylurea) 3- (3,4-dichlorophenyl) -1,1'-dimethylurea and SP-150, a commercial product of a cationic photopolymerization catalyst, manufactured by Asahi Denka Co., Ltd.
P-170 and the like.

Specific examples of the solvent (C) include, for example, ethyl cellosolve, isopropyl cellosolve, butyl cellosolve, diethylene glycol monoacetate, ethyl carbitol, butyl carbitol, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, dipropylene glycol monomethyl ether. And solvent naphtha. Each component (A) to (C) contained in the solder resist ink composition of the present invention
Is 100 parts by weight of the component (A),
Component (B) is preferably 0.5 to 60 parts by weight, particularly preferably 1 to 30 parts by weight, and component (C) is preferably 20 to 60 parts by weight, particularly preferably 30 to 50 parts by weight.

The composition of the present invention may further contain various additives such as talc, silica, alumina, barium sulfate,
An extender such as magnesium oxide, a thixotropic agent such as Aerosil, a leveling agent such as silicone or acrylate copolymer, an antifoaming agent, a flame retardant, and a coloring agent can be added. Any of these various additives can be added to the composition. Further, a novolak type epoxy resin, a bisphenol type epoxy resin or the like can be added.

The composition of the present invention can be produced by uniformly mixing the components. The composition of the present invention is cured by heating to 130 ° C. or higher by a conventional method to obtain a cured product of the present invention. In general use of the composition of the present invention, the composition of the present invention is printed on a substrate by screen printing or the like, and then cured by heating (130 to 170).
C.) to form a protective film (usually 10 to 100 μm) on the substrate.
m cured film). When a cationic polymerization catalyst is used as a curing agent, it is necessary to irradiate ultraviolet rays before curing by heating.

[0082]

The present invention will be described below in more detail with reference to examples. The numbers in the examples represent parts by weight.

Synthesis Example 1 R ₁ and R ₂ in the formula (3) are

[0084]

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In the polyglycidyl ether of tris (hydroxyphenyl) methane, the average value of n in the formula (2) is 0.78, the epoxy equivalent is 205, the hydrolyzable chlorine content is 0.071%, and the softening point is 71. After dissolving 199 parts of epoxy resin (e) of epoxy resin (e) in 370 parts of epichlorohydrin at 0 ° C. and a melt viscosity (150 ° C.) of 3.6 poise, 6 parts of tetramethylammonium chloride is added at 70 ° C. with stirring, and then 48 parts. 30 parts of NaOH was added dropwise over 100 minutes, and the mixture was further reacted for 3 hours at 70 ° C. After the completion of the reaction, 200 parts of water was added and washed with water, and after separating oil and water, most of epichlorohydrin was distilled off from the oil layer under reduced pressure. And then add methyl isobutyl ketone 450
And then further added 5 parts of 30% NaOH,
For 1 hour. After the completion of the reaction, the resultant was washed twice with 200 parts of water. After oil-water separation, methyl isobutyl ketone is distilled and recovered from the oil layer to obtain an epoxy resin having an epoxy equivalent of 189, a hydrolyzable chlorine content of 0.071%, a softening point of 71.0 ° C, and a dissolution viscosity (150 ° C) of 3.6 poise. (A) 195
Got a part. When the obtained epoxy resin (a) is calculated from the epoxy equivalent, about 0.46 of the 0.78 alcoholic hydroxyl groups in the formula (3) are epoxidized.

Synthesis Example 2 Epoxy resin (e) used in Synthesis Example 1 (199 parts) was replaced with 370 parts of epichlorohydrin and 185 parts of dimethyl sulfoxide.
And 98.5% NaOH at 70 ° C. with stirring.
10.6 parts were added over 100 minutes. 7 more after addition
The reaction was performed at 0 ° C. for 3 hours. Next, most of the excess unreacted epichlorohydrin and dimethyl sulfoxide are distilled off under reduced pressure, the reaction product containing by-product salt and dimethyl sulfoxide is dissolved in 450 parts of methyl isobutyl ketone, and 5 parts of 30% NaOH is added. For 1 hour. After the completion of the reaction, the resultant was washed twice with 200 parts of water. After oil-water separation, methyl isobutyl ketone was distilled and recovered from the oil layer to obtain an epoxy equivalent of 187, a hydrolyzable chlorine content of 0.07%, a softening point of 71.0 ° C., and a melt viscosity of 150 ° C.
C.) 197 parts of a 3.5 poise epoxy resin (b) were obtained. When the obtained epoxy resin (b) was calculated from the epoxy equivalent, the alcoholic hydroxyl group in the formula (3) was 0.78.
About 0.52 of them are epoxidized.

Synthesis Example 3 When R ₁ and R ₂ in the formula (3) are

[0088]

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In the epoxy resin, the average value of n in the formula (3) is 1.46, the epoxy equivalent is 308, the hydrolyzable chlorine content is 0.107%, the softening point is 88.0 ° C.,
Epoxy resin having a melt viscosity (150 ° C.) of 16 poise (same as in Synthesis Example 1 except that 188 parts of epoxy resin (f) was used, epoxy equivalent 241, hydrolyzable chlorine content 0.074%, softening point 82) 0.0 ° C, melt viscosity (150
C.) 187 parts of 11.0 poise epoxy resin (c) were obtained. When the obtained epoxy resin (c) is calculated from the epoxy equivalent, the alcoholic hydroxyl group 1.46 in the formula (3) is obtained.
Most of the pieces are epoxidized.

Synthesis Example 4 R ₁ and R ₂ in the formula (3) are

[0091]

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(Where p represents 0 or an integer of 1 or more), the average value of n in the formula (3) is 0.38, the average p in the above formula is 2.2, Epoxy equivalent 199, hydrolyzable chlorine content 0.035%, softening point 45.0 ° C, melt viscosity (1
50 ° C.) An epoxy equivalent of 19 was obtained in the same manner as in Synthesis Example 2 except that 240 parts of a 0.5 poise epoxy resin (g) was used.
0, hydrolyzable chlorine content 0.034%, softening point
241 parts of an epoxy resin (d) having a melt viscosity (150 ° C.) of 0.5 poise at 5 ° C. was obtained. The obtained epoxy resin (d)
When calculated from the epoxy equivalent, about 0.33 of the 0.38 alcoholic hydroxyl groups in the formula (3) are epoxidized.

Examples 1 to 4 and Comparative Examples 1 and 2 Each component was blended according to the blending composition shown in Table 1 and kneaded using three rolls to obtain a solder resist ink composition. This ink composition was applied to a printed wiring board by a screen printing method so that the film thickness became about 25 μm.
Heating was performed at 0 ° C. for 30 minutes to cure, thereby obtaining a printed wiring board having a protective film. (Note that in Example 3, the film was dried at 80 ° C. for 30 minutes and irradiated with ultraviolet rays [500 mJ / m ² ] before being cured by heating.) The protective film and the ink composition of the obtained printed wiring board were obtained. , Various performance tests were performed as follows. Table 2 shows the results.

[Toluene solubility of ink composition]: 5 g of the ink composition is dissolved in 50 g of toluene. ○ ・ ・ ・ Dissolved △ ・ ・ ・ ・ Semi-dissolved × ・ ・ ・ ・ ・ ・ Insoluble

[Evaluation of Physical Properties of Protective Film] (Pencil hardness): Measured according to JIS-K-5400 (Adhesion): Baseline test according to JIS-D-0202 (the number of unpeeled out of 100 bases) (heat resistance) ): The state of the coating film after being immersed in molten solder at 260 ° C. for 180 seconds was determined. ○ ・ ・ ・ ・ No abnormality at all. × ··· Discoloration, peeling, blistering (gold plating resistance): manufactured by Uemura Kogyo Co., Ltd., Alna 533
Conditions: 1 A / dm ² , 15 minutes, plating thickness, 2 μm ・ ・ ・: No abnormality. ×: discoloration, peeling, blistering (acid resistance): The state of the coating film after immersion in a 10 Vol% H ₂ SO ₄ aqueous solution at room temperature was determined. ◎ ・ ・ ・ ・ ・ ・ No abnormality up to 48 hours ○ ・ ・ ・ ・ No abnormality up to 24 hours △ ・ ・ ・ ・ No abnormality up to 8 hours × ・ ・ ・ ・ Peeling and blistering in 1 hour (Alkali resistance): 10wt% NaOH The state of the coating film after immersion in an aqueous solution at room temperature was determined. ○ ・ ・ ・ No abnormality up to 30 days △ ・ ・ ・ ・ No abnormality up to 15 days × ・ ・ ・ ・ Within 7 days, peeling and blistering (thermal deformation temperature): TMA method, Shimadzu thermal analyzer TMA-4
0

(Electrical insulation resistance): Measured according to JIS-Z-3197 (Bleed): Measured the bleed width (μm) of the ink composition (Discoloration of the protective film during heat curing of the ink composition) "Discoloration of the protective film" is shown.): The state of discoloration of the protective film during heat curing (150 ° C., 60 minutes) was determined. ○ ・ ・ ・ No abnormality △ ・ ・ ・ ・ Discoloration × ・ ・ ・ ・ Discoloration severe

Table 1 (1) Example 1 2 3 4 Epoxy resin (a) 100 〃 (b) 100 〃 (c) 100 50 〃 (d) 50 Epicoat 828 * 1 Epicoat 1001 * 2 Epicoat 180 * 3 Dicyandiamide 8 8 8 2-Ethyl-4-methylimidazole 7 7 Triazine compound * 46 SP-170 * 53 Carbitol acetate 30 30 30 30 Butyrocellosolve acetate Solvent naphtha 10 10 10 10 Extender pigment, talc 10 10 10 10 Sulfuric acid Barium 50 50 50 50 Aerosil 1.0 1.0 1.0 1.0 Color pigment, phthalocyanine green 6 6 6 6 Antifoam, TSF401 * 6 2.0 2.0 2.0 2.0

[0098]

Note * 1 Epicoat 828: Yuka Shell Epoxy Co., Ltd., bisphenol A type epoxy resin * 2 Epicoat 1001 ... Yuka Shell Epoxy Co., Ltd., bisphenol A type epoxy resin * 3 YDN-180: Toto Kasei Co., Ltd., phenol novolak type epoxy resin * 4 2,4-diamino-6- [2'-methylimidazole (1) ']-ethyl-S-triazine * 5 SP-170 ... Asahi Denka Co., Ltd. Cationic photopolymerization catalyst * 6 Toshiba Silicon Corporation, defoamer

Table 2 (1) Example 1 2 3 4 Toluene solubility of ink composition ○ ○ ○ ○ Lead brush hardness 8H 8H 8H 8H Adhesion 100 100 100 100 Heat resistance ○ ○ ○ ○ Gold plating resistance ○ ○ ○ ○ Alkali resistance ○ ○ ○ ○ Acid resistance ◎ ◎ ◎ ◎ Thermal deformation temperature (℃) 240 242 233 200 Electrical insulation resistance (Ω) × 10 ¹¹ 0.9 0.9 0.8 0.9 Bleed (μm) Within 25 Within 25 Within 25 Within 25 Discoloration of protective film ○ ○ ○ ○

[0101]

Example 5 Instead of using dicyandiamide and 2,4-diamino-6- [2'-methylimidazolyl- (1) ']-ethyl-S-triazine as the curing agent (B) in Example 1, dicyandiamide 8 0.5 parts, and 6.0 parts of 3- (3,4-dichlorophenyl) -1,1′-dimethylurea were used to prepare a solder resist ink composition, and the same experiment was performed. The result was obtained.

Example 6 Instead of using dicyandiamide and 2,4-diamino-6- [2'-methylimidazolyl- (1) ']-ethyl-S-triazine as the curing agent (B) in Example 1, KAYAHARD AS (manufactured by Nippon Kayaku Co., Ltd.
A solder resist ink composition was prepared using 30 parts of an aromatic amine-based epoxy curing agent), and the same experiment was performed. The same results as in Example 1 were obtained.

As shown in Table 2, the solder resist ink composition of the present invention has excellent solubility in solvents,
In the cured product, the cured film has a high heat distortion temperature,
In addition, the ink composition has excellent heat resistance, moisture resistance, high hardness, plating resistance, chemical resistance, and electrical insulation. The ink composition has less bleeding and discoloration during heat curing is not observed.

[0105]

The solder resist ink composition of the present invention has a cured film having a high heat deformation temperature and excellent heat resistance, moisture resistance, high hardness, plating resistance, chemical resistance and electrical insulation. With low bleed.

Claims (6)

(57) [Claims] (1) Formula (1) (In the formula, R ₁ and R ₂ are the same or different and each represents a residue of a compound having two or more phenolic hydroxyl groups from which the hydroxyl group has been removed. Z ₁ and Z ₂ are the same or different and are 0 or an integer of 1 or more. And the sum of Z ₁ and Z ₂ is 1 or more, and M is a glycidyl group or a hydrogen atom, and n is an integer of 1 or more, provided that when n is 1, M is always a glycidyl group. And when n is 2 or more, at least one of M is a glycidyl group.) A solder resist ink composition containing an epoxy resin (A). 2. A solder resist ink composition comprising the epoxy resin (A) according to claim 1, a curing agent (B), and a solvent (C). 3. The curing agent according to claim 2, wherein the curing agent (B) is one or more selected from the group consisting of dicyandiamide, imidazole compounds, triazine compounds, urea compounds, aromatic amine compounds and cationic photopolymerization catalysts. Solder resist ink composition. 4. The solvent (C) is represented by the formula (2). (Wherein, R ₁ is a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, R ₂ is an ethylene group which may be substituted by a methyl group, R ₃ is a hydrogen atom or And R ₄ represents an alkyl group having 1 to 8 carbon atoms. However, R ₁ and R ₃ are not hydrogen atoms at the same time. n
Represents an integer of 1 to 4. ) And solvent naphtha. The solder resist ink composition according to claim 1, wherein the composition is one or more types. 5. A cured product of the solder resist ink composition according to claim 1, 2 or 3. 6. A cured product of the solder resist ink composition according to claim 4.