KR101458288B1 - Thermosetting resin composition and printed wiring board - Google Patents

Abstract

(A) an epoxy compound having no aromatic ring, (B) a rutile-type titanium oxide, (C) a carboxyl group-containing resin, and (D) an organic solvent and prevents discoloration due to light or heat generation, And a printed wiring board.

Description

TECHNICAL FIELD [0001] The present invention relates to a thermosetting resin composition and a printed wiring board,

The present invention relates to a white heat curable resin composition having high reflectance suitable as an insulating layer of a printed wiring board on which a light emitting element such as a light emitting diode (LED) is mounted, and a printed wiring board having an insulating layer made of a cured product of the composition.

2. Description of the Related Art In recent years, the printed wiring board has been increasingly used for mounting directly on an LED that emits light at a low power, such as a backlight of a liquid crystal display such as a portable terminal, a personal computer, and a television, , Japanese Patent Application Laid-Open No. 2007-249148 (paragraphs 0002 to 0007)).

In that case, the insulating film formed as a protective film on the printed wiring board is required to have a light reflectance such that the light emission of the LED can be effectively utilized, in addition to the solvent resistance, hardness, solder heat resistance, Excellent.

However, in the white solder resist composition conventionally used, the oxidation of the resin proceeds due to the light emitted from the LED or heat generation, resulting in yellowing, and the reflectance is lowered with time.

SUMMARY OF THE INVENTION An object of the present invention is to provide a thermosetting resin composition and a printed wiring board capable of preventing discoloration due to light or heat generation and preventing a decrease in reflectance over time.

The inventors of the present invention have conducted intensive studies for realizing the above object and found that by using an epoxy compound having no aromatic ring as an epoxy compound component, it is possible to prevent discoloration due to light or heat generation, It is possible to provide a resin composition, and have reached the present invention of the present invention.

That is, the thermosetting resin composition of the present invention is characterized by containing (A) an epoxy compound having no aromatic ring, (B) a rutile titanium oxide, (C) a carboxyl group-containing resin, and (D) an organic solvent.

Further, the inventors of the present invention have found out that, in the above examination, when an epoxy compound hardly soluble in an organic solvent such as TEPIC-S manufactured by Nissan Chemical Industries, Ltd. is used as an epoxy compound, a white color composed of two main components, The problem of difficulty in liquefying the thermosetting resin composition was recognized.

Therefore, the inventors also intensively studied the composition of the composition which facilitates two-liquefaction of the composition. As a result, it has been found that an epoxy compound (A) having no aromatic ring is preferably an epoxy compound which is liquid at room temperature or soluble in organic solvents Could know.

According to the resin composition of the present invention, discoloration due to light or heat generation can be prevented, and the degradation of the reflectance over time can be prevented.

Further, according to a preferred embodiment of the present invention, the liquefaction (main agent and curing agent) of the white thermosetting resin composition is facilitated by using an epoxy compound which is liquid or soluble in an organic solvent at room temperature.

Hereinafter, embodiments of the present invention will be described in detail.

The thermosetting resin composition according to the present invention comprises an epoxy compound (A) having no aromatic ring, rutile titanium oxide (B), a carboxyl group-containing resin (C) and an organic solvent (D).

(An epoxy compound having no aromatic ring)

The epoxy compound (A) having no aromatic ring is preferably an epoxy compound which is liquid at room temperature or soluble in an organic solvent.

For example, it is preferable to use a copolymer resin obtained from a compound having an unsaturated double bond and a compound having an oxirane ring and an ethylenic unsaturated group in one molecule.

Examples of the compound having an unsaturated double bond as a component constituting the copolymer resin include compounds having an unsaturated double bond such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) (Meth) acrylate, 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, caprolactone modified 2 (Meth) acrylates such as methoxyethyleneglycol (meth) acrylate, ethoxydiethyleneglycol (meth) acrylate, isooctyloxydiethylene glycol (meth) acrylate, , Glycol-modified (meth) acrylates such as methoxy triethylene glycol (meth) acrylate and methoxypolyethylene glycol (meth) acrylate, etc. The can. These may be used alone or in combination of two or more. In the present specification, (meth) acrylate is a generic term for acrylate and methacrylate, and the same applies to other similar expressions.

As the compound having an oxirane ring and an ethylenic unsaturated group in one molecule, it is particularly preferable to use a compound produced from an aliphatic monomer. Specific examples thereof include glycidyl (meth) acrylate,? -Methyl glycidyl (meth) 3,4-epoxycyclohexylmethyl (meth) acrylate, 3,4-epoxycyclohexylethyl (meth) acrylate, 3,4-epoxycyclohexylbutyl (meth) Aminoacrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, and the like. The compounds having an oxirane ring and an ethylenic unsaturated group in one molecule may be used alone or in admixture of two or more.

The epoxy equivalent (A) of the copolymerizable epoxy compound having no aromatic ring is preferably in the range of 50 to 1,000 g / mol. More preferably 100 to 800 g / mol. When the epoxy equivalent is less than 50 g / mol, the crosslinking becomes insufficient, and as a result, the adhesiveness and the pencil hardness are lowered. If it is more than 1,000 g / mol, the crosslinking density is lowered and sufficient curing is not carried out, resulting in poor water resistance and electrical properties of the cured coating. The weight average molecular weight of the epoxy compound (A) having no aromatic ring is preferably in the range of 3,000 to 100,000. More preferably from 5,000 to 30,000. If the weight average molecular weight is less than 3,000, the light resistance and heat resistance tend to be significantly poor. When the weight average molecular weight exceeds 100,000, the leveling property and defoaming property at the time of printing are remarkably lowered.

The amount of the epoxy compound (A) having no aromatic ring is preferably 5 to 100 parts by mass, more preferably 5 to 60 parts by mass, based on 100 parts by mass of the carboxyl group-containing resin (C). When the blending amount of the epoxy compound (A) exceeds 100 parts by mass, the proportion of the epoxy compound (A) increases, which leads to over-crosslinking, and as a result, discoloration of the coating film is likely to occur. On the other hand, if it is less than 5 parts by mass, sufficient curing is not performed, and as a result, adhesiveness, pencil hardness and moisture resistance are remarkably impaired, and a practical coating film can not be obtained.

The epoxy group of the epoxy compound having no aromatic ring and the carboxyl group of the carboxyl group-containing resin react by ring-opening polymerization.

(Rutile type titanium oxide)

In the present invention, rutile titanium oxide (B) is used as a white pigment. Common titanium oxides include anatase and rutile. Since the anatase-type titanium oxide has photocatalytic activity, there is a case where discoloration of the resin in the solder resist composition occurs. On the other hand, the rutile-type titanium oxide has absorption in the vicinity of the boundary between the ultraviolet ray region and the visible light region as compared with the anatase-type titanium oxide, and is poor in terms of whiteness and reflectivity of the entire visible light region. However, A resist film can be obtained.

As the rutile-type titanium oxide, a known titanium oxide can be used. More specifically, it is possible to use the Tape R-820, Taipei R-830, Taipei R-930, Taipei R-550, Taipei R-630, Taipei R-680, Taipei R- 680, Taipei R-670, Taipei R-780, Taipei R-850, Taipei CR-50, Taipei CR-57, Taipei CR- Taipei Cr-95, Taipei CR-95, Taipei CR-95, Taipei CR-97, Taipei CR-60, Taipei CR-63, Taipure R-101, Taipure R-102, Taipure R-103, Taipure R-104, Taipure R-105, Taipure R- (TITON) R-25, TITON R-21, TITON R-321, and TITON R-931 (manufactured by DuPont Kabushiki Kaisha) , TITON R-7E, TITON R-5N, TITON R-61N, TITON R-62N, Tone TCR-29, TITON R-45, TITON R-49, TITON R-49S, TITON GTR-100, TITON GTR-300, TITON D-918, TITON TCR-29, TITON TCR- Manufactured by Sakai Chemical Industry Co., Ltd.).

The blending amount of the rutile titanium oxide is preferably 50 to 450 parts by mass, and more preferably 60 to 350 parts by mass with respect to 100 parts by mass of the carboxyl group-containing resin. When the blending amount exceeds 450 parts by mass, adhesion and leveling property at the time of printing deteriorate, which is not preferable. On the other hand, if the blending amount is less than 50 parts by mass, the hiding power is low and a solder resist with high reflectance can not be obtained.

(Carboxyl group-containing resin)

As the carboxyl group-containing resin (C), a photosensitive carboxyl group-containing resin having at least one photosensitive unsaturated double bond in itself and a carboxyl group-containing resin having no photosensitive unsaturated double bond can be used, .

For example, as the carboxyl-containing resin (C), a copolymer resin obtained by copolymerization of a compound having an unsaturated carboxylic acid and an unsaturated double bond can be given.

Examples of the unsaturated carboxylic acid constituting such a copolymer resin include acrylic acid, methacrylic acid, a modified unsaturated monocarboxylic acid in which a chain between the unsaturated group and the carboxylic acid is extended, such as? -Carboxyethyl (meth) acrylate, 2 - unsaturated monocarboxylic acids having an ester bond by means of acryloyloxyethylsuccinic acid, 2-acryloyloxyethylhexahydrophthalic acid, lactone modification or the like, modified unsaturated monocarboxylic acids having an ether bond, and carboxyl groups such as maleic acid Containing two or more compounds in the molecule. These may be used alone or in combination of two or more.

Examples of the compound having an unsaturated double bond include styrene, chlorostyrene,? -Methylstyrene; Examples of the substituent include a methyl group, an ethyl group, a n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an amyl group, a 2-ethylhexyl group, an octyl group, a caprylyl group, a nonyl group, a dodecyl group, a hexadecyl group, (Meth) acrylate having isobornyl, methoxyethyl, butoxyethyl, 2-hydroxyethyl, 2-hydroxypropyl, 3-chloro-2-hydroxypropyl and the like; Mono (meth) acrylates of polyethylene glycol or mono (meth) acrylates of polypropylene glycol; Vinyl acetate, vinyl butyrate, vinyl benzoate; Acrylamide, methacrylamide, N-hydroxymethylacrylamide, N-hydroxymethylmethacrylamide, N-methoxymethylacrylamide, N-ethoxymethylacrylamide, N-butoxymethylacrylamide, Nitrile, vinyl ethers, or isobutylene. These compounds may be used alone or in combination of two or more.

In the present invention, among these carboxyl group-containing resins, a carboxyl group-containing resin having no aromatic ring can be suitably used. As a result, the prevention of discoloration due to light or heat can be more clearly ensured.

The carboxyl group-containing resin (C) preferably has an acid value in the range of 30 to 200 mgKOH / g. More preferably 50 to 100 mgKOH / g. When the acid value is less than 30 mgKOH / g, the crosslinking becomes insufficient, and as a result, the adhesiveness and the pencil hardness are lowered. If it exceeds 200 mgKOH / g, there is a problem that the water resistance is lowered and the water resistance and electric characteristics of the cured coating are poor. The weight average molecular weight of the carboxyl group-containing resin (A) is preferably in the range of 1,000 to 100,000. More preferably from 5,000 to 50,000. If the weight average molecular weight is less than 1000, the light resistance and heat resistance tend to be remarkably poor. When the weight average molecular weight exceeds 100,000, the leveling property and defoaming property at the time of printing are remarkably lowered.

(Organic solvent)

The organic solvent (D) used in the present invention is used for forming a film by placing the solder resist composition in a state in which it is easy to apply, applying it to a substrate or the like, followed by drying. Examples of such organic solvents include ketones such as methyl ethyl ketone and cyclohexanone; Aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; Methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, diethylene glycol monoethyl ether, dipropreneglycol monoethyl ether, triethylene glycol monoethyl ether And the like; Esters such as ethyl acetate, butyl acetate, cellosolve acetate, diethylene glycol monoethyl ether acetate and esters of the glycol ethers; Alcohols such as ethanol, propanol, ethylene glycol and propylene glycol; Aliphatic hydrocarbons such as octane and decane; Petroleum ether such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha and solvent naphtha.

The organic solvent may be used alone or as a mixture of two or more thereof. The blending amount of the organic solvent is preferably 20 to 300 parts by mass based on 100 parts by mass of the carboxyl group-containing resin.

(Antioxidant)

In the present invention, even when the cured product of the solder resist is exposed to a high temperature over a long period of time, an antioxidant is suitably used in order to prevent the cured product from lowering in reflectance or coloring. Examples of such antioxidants include n-octadecyl-3- (3'5'-di-t-butyl-4'-hydroxyphenyl) -propionate, n-octadecyl- (3'5'-di-t-butyl-4'-hydroxyphenyl) -propionate, 1-tert- (3,5-di-t-butyl-4-hydroxyphenyl) propionate), 1,4-butanediol-bis- (3- (3-t-butyl-5-methyl-4-hydroxyphenyl) -propionate), triethylene glycol-bis- (3, 5-di-t-butyl-4'-hydroxyphenyl) propionate methane, 3,9-bis Methylphenyl) propionyloxy) -1,1-dimethylethyl) 2,4,8,10-tetraoxaspiro (5,5) undecane, N, N'- (3'-methyl-5'-t-butyl-4-hydroxyphenol) propionylhexamethylenediamine, N, N'- Hydroxyphenol) N, N'-bis- (3- (3,5-di-t-butyl-4-hydroxyphenol) propionyl) hydrazine, N-salicyloyl-N'-salicylidene hydrazine, N, N'-bis (2- (3- (3,5-di-butyl-4-hydroxyphenyl) propionyloxy) ) Ethyl) oxyamide, and a hindered phenol compound such as didodecyl-3,3'-thiodipropionate, ditetradecyl-3,3'-thiodipropionate, dioctadecyl-3,3'- Thiodipropionate, ditridecyl-3,3'-thiodipropionate, pentaerythrityl tetrakis (3-dodecylthiopropionate), pentaerythrityl tetrakis (3-tetradecylthio Propionate), pentaerythrityl tetrakis (3-tridecylthiopropionate), dilauryl-3,3-thiodipropionate, dimyristyl-3,3-thiodipropionate, 3-thiodipropionate, pentaerythrityl tetrakis (3-lauryl tei Dipropionate), 2-mercaptobenzimidazole, laurylstearyl thiodipropionate, the zinc salt of 2-mercaptomethylbenzimidazole, the zinc salt of 2-mercaptobenzimidazole, the 2- Sulfur antioxidants such as mercaptomethyl benzimidazole and zinc dibutyl thiocarbamate; antioxidants such as triphenylphosphite, tris (methylphenyl) phosphite, triisooctylphosphite, tridecylphosphite, tris (2-ethylhexyl) (Octylphenyl) phosphite, tris (cyclohexylphenyl) phosphite, tricyclohexyl phosphite, tri (decyl) thiophosphite, tris , Triisodecylthiophosphite, phenyl · bis (2-ethylhexyl) phosphite, phenyl · diisodecylphosphite, tetradecylpoly (oxyethylene) · bis (ethylphenyl) phosphite, phenyl · dicyclohexylphosphine Fight, Pee Diisooctyl phosphite, phenyl di (tridecyl) phosphite, diphenyl cyclohexyl phosphite, diphenyl isooctyl phosphite, diphenyl 2-ethylhexyl phosphite, diphenyl isodecyl phosphite Phosphorus antioxidants such as diphenyl cyclohexyl phenyl phosphite and diphenyl (tridecyl) thiophosphite, phenyl naphthyl amine, 4,4'-dimethoxydiphenyl amine, 4,4'-bis di (octylphenyl) amine, 4-isopropoxydiphenylamine, N, N'-di (2-naphthylphenyl) And aromatic amine-based antioxidants such as p-phenylenediamine. One or more of these may be selected and used in combination. Among them, a hindered phenol compound is preferable because of a reduction in reflectance and a high effect of prevention of coloring. Examples of trade names of antioxidants for hindered phenol compounds include Nocrack 200, Nocrack M-17, Nocrack SP, Nocrack SP-N, Nocrack NS-5, Nocrack NS-6, Nocrack NS- Crack 300, Nocrack NS-7, Nocrack DAH (all manufactured by Ouchi Shinko Chemical Industry Co., Ltd.); MARK AO-30, MARK AO-40, MARK AO-50, MARK AO-60, MARK AO-616, MARK AO-635, MARK AO-658, MARK AO-15, MARK AO-18, MARK 328 , Mark AO-37 (all manufactured by ADEKA); Irganox 245, Irganox 259, Irganox 565, Irganox 1010, Irganox 1035, Irganox 1076, Irganox 1081, Irganox 1098, Irganox 1222, Irganox 1330, Irganox 1425WL (all manufactured by Shiba, Japan).

The blending amount of the antioxidant is preferably 0.4 to 25 parts by mass, more preferably 0.8 to 15 parts by mass based on 100 parts by mass of the carboxyl group-containing resin. When the blending amount of the antioxidant is less than 0.4 part by mass based on 100 parts by mass of the carboxyl group-containing resin, the effect of preventing discoloration due to thermal deterioration of the solder resist is small. When the blending amount of the antioxidant exceeds 25 parts by mass based on 100 parts by mass of the carboxyl group-containing resin, curing inhibition occurs and adhesion is lowered.

Further, a curing agent and / or a curing catalyst may be added to the white thermosetting resin composition of the present invention.

 Examples of the curing agent include a polyfunctional phenol compound, an acid anhydride thereof, an aliphatic or aromatic primary or secondary amine, a polyamide resin, and a polymeric compound. Among them, a polyfunctional phenol compound and an acid anhydride thereof are preferably used in terms of workability and insulation.

Among these curing agents, the polyfunctional phenol compound may be a compound having two or more phenolic hydroxyl groups in one molecule, and a known one may be used. Specific examples thereof include phenol novolac resins, cresol novolak resins, bisphenol A, allyl bisphenol A, bisphenol F, novolak resins of bisphenol A, and vinylphenol copolymer resins. Particularly, And the effect of increasing the heat resistance is also high. These polyfunctional phenolic compounds are additionally reacted with the epoxy compounds in the presence of an appropriate curing catalyst.

 The compounding amount of these curing agents is usually sufficient in a quantitative ratio that is usually used, and is preferably 1 to 200 parts by mass, more preferably 10 to 100 parts by mass, per 100 parts by mass of the epoxy compound.

Next, the curing catalyst will be described.

The curing catalyst is a compound which can be used as a curing catalyst in the reaction of the epoxy compound with the curing agent or a polymerization catalyst when the curing agent is not used. Examples thereof include tertiary amines, tertiary amine salts, 4 A tertiary phosphine, a crown ether complex, and a phosphonium iodide. Of these, they may be used alone or in combination of two or more.

Of these, preferred are imidazoles such as 2E4MZ, C11Z, C17Z and 2PZ, azine compounds of imidazoles such as 2Z-A and 2E4MZ-A, 2MZ-OK and 2PZ- Imidazole hydroxymethyl derivatives such as 2PHZ and 2P4MHZ (all of which are trade names, manufactured by Shikoku Chemicals Inc.), dicyandiamide and its derivatives, melamine and its derivatives, diaminomalonitrile and its derivatives Amines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, bis (hexamethylene) triamine, triethanolamine, diaminodiphenylmethane and organic acid dihydrazide, 1,8-diazabicyclo [ (3-aminopropyl) -2,4,8,10-tetraoxaspiro [5,5] undecane (trade name: DBU, (Trade name ATU, manufactured by Ajinomoto Co., Ltd.) or triphenylphosphine, tricyclohexylphosphine, And organic phosphine compounds such as tributylphosphine and methyldiphenylphosphine.

The compounding amount of these curing catalysts is usually sufficient in the usual quantitative ratio, and is preferably 0.05 to 10 parts by mass, more preferably 0.1 to 3 parts by mass, per 100 parts by mass of the epoxy compound not having the aromatic ring.

The white thermosetting resin composition of the present invention may further contain, if necessary, a known thickening agent such as finely divided silica, organic bentonite, and montmorillonite, a defoaming agent such as a silicone type, a fluorine type, a high molecular type and the like and a leveling agent, an imidazole type, Silane coupling agents such as triazole-based coupling agents, and the like. In addition, the coloring agent can be incorporated in the range of not damaging the white color of the thermosetting resin composition of the present invention. In particular, phthalocyanine is effective to function as an anti-settling agent and bluing.

The white thermosetting resin composition of the present invention is coated with a suitable viscosity for the application method with the above-mentioned organic solvent, and is coated on the substrate by a screen printing method or the like. After the application, the cured coating film can be obtained by heating at a temperature of, for example, 140 ° C to 180 ° C for thermal curing.

The cured coating film of the white thermosetting resin composition according to the present invention is suitably used not only as a solder resist layer in a printed wiring board but also as a reflective plate for a component requiring high reflectance, Can be used.

<Examples>

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but it should be understood that the present invention is not limited thereto.

Synthetic example

Synthesis Example 1 of a carboxyl group-containing resin having no aromatic ring

In a 2-liter separable flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel and a nitrogen inlet tube, 900 g of diethylene glycol dimethyl ether as a solvent and t-butylperoxy 2-ethylhexanoate (Nippon Oil Co., 21.4 g, manufactured by Nippon Synthetic Chemical Industry Co., Ltd .; perbutyl O) was added and heated to 90 占 폚. After heating, 86 g of methacrylic acid and 849 g of methyl methacrylate were added to 21.4 g of bis (4-t-butylcyclohexyl) peroxydicarbonate (trade name: PEROIL TCP, And aged for another 6 hours to obtain a resin composition containing 51.0% by mass (nonvolatile content) of a carboxyl group-containing resin having an acid value of 60.0 mgKOH / g and a weight average molecular weight of 15,000, Solution. The reaction was carried out in a nitrogen atmosphere. Hereinafter, this reaction solution is referred to as A-1 varnish.

Synthesis Example 2 of a carboxyl group-containing resin having no aromatic ring

In a 2-liter separable flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel and a nitrogen inlet tube, 900 g of diethylene glycol dimethyl ether as a solvent and t-butylperoxy 2-ethylhexanoate (Nippon Oil Co., 21.4 g, manufactured by Nippon Synthetic Chemical Industry Co., Ltd .; perbutyl O) was added and heated to 90 占 폚. After heating, 309.9 g of methacrylic acid, 116.4 g of methyl methacrylate, and 109.8 g of lactone-modified 2-hydroxyethyl methacrylate (trade name: Fraxel FM1, manufactured by Daicel Chemical Industries, Ltd.) Was added dropwise over 3 hours with 21.4 g of bis (4-t-butylcyclohexyl) peroxydicarbonate (manufactured by Nippon Oil Co., Ltd., trade name: PEROIR TCP), followed by aging for another 6 hours to obtain a carboxyl- . The reaction was carried out in a nitrogen atmosphere.

Next, 363.9 g of 3,4-epoxycyclohexylmethyl acrylate (trade name: CYROMER A200, manufactured by Daicel Chemical Industries, Ltd.), 3.6 g of dimethylbenzylamine as a ring-opening catalyst, , 1.80 g of hydroquinone monomethyl ether was added and heated to 100 占 폚 and stirred to carry out the ring-opening addition reaction of epoxy. After 16 hours, a solution containing 53.8% by mass (nonvolatile content) of a carboxyl group-containing resin having no aromatic ring having an acid value of solid content of 108.9 mgKOH / g and a weight average molecular weight of 25,000 was obtained. Hereinafter, this reaction solution is referred to as A-3.

Among the epoxy copolymer compounds having no aromatic ring, Synthesis Example 3 of an epoxy resin compound soluble in an organic solvent

In a 2-liter separable flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel and a nitrogen inlet tube, 900 g of diethylene glycol dimethyl ether as a solvent and t-butylperoxy 2-ethylhexanoate (Nippon Oil Co., 21.4 g, manufactured by Nippon Synthetic Chemical Industry Co., Ltd .; perbutyl O) was added and heated to 90 占 폚. After the heating, 778.6 g of methyl methacrylate and 241.1 g of glycidyl methacrylate were added to this solution with bis (4-t-butylcyclohexyl) peroxydicarbonate (trade name; manufactured by Nippon Oil Co., ) Was added dropwise over 3 hours, followed by aging for 6 hours to obtain 52.0 mass% (nonvolatile content) of an epoxy group-containing copolymer resin having an average molecular weight of 15000 and an epoxy equivalent weight of 600 g / Was obtained. The reaction was carried out in a nitrogen atmosphere. Hereinafter, this reaction solution is referred to as a varnish B.

Blends of Examples 1 to 4 and Comparative Examples 1 to 3:

Each component was blended and stirred according to Table 1 and dispersed with a three-roll mill to prepare a solder resist composition. Numbers in the tables indicate mass parts.

Remarks

A-2 Varnish: A 56:46 (mass ratio) mixed varnish (carboxyl group-containing resin having no aromatic ring) of John Krill 67 (styrene acrylic copolymer resin (BASF JAPAN Ltd.) and carbitol acetate)

Curing catalyst 1; Melamine

Curing catalyst 2; Dicyandiamide

Titanium oxide; R820 (rutile-type titanium oxide manufactured by Ishihara Sangyo)

Tepic-S; (Manufactured by Nissan Chemical Industries, Ltd.)

828; Bisphenol type epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd.)

Antioxidant: Irganox 1010 (manufactured by Shiba, Japan)

Solvent: Carbitol acetate

Defoamer (silicone oil): KS-66 (Shin-Etsu Silicon)

In order to investigate various properties of the solder resist formed using each solder resist composition, evaluation and evaluation were conducted as follows.

In Comparative Example 3, TEPHIC-S of the curing agent composition was not dissolved in the solvent component and could not be inked, so that evaluation was impossible.

Test board fabrication

The solder resist compositions of Examples 1 to 4 and Comparative Examples 1 and 2 were applied to a FR-4 copper-clad laminate having a size of 100 mm x 150 mm and a thickness of 1.6 mm by screen printing to a thickness of 25 m in a 100 mesh polyester (A bias plate) was used to print a pattern on a beta (entire surface of the substrate) and cured in a hot-air circulation type drying furnace at 150 DEG C for 30 minutes to prepare a test piece for characteristics test.

(1) Heat resistance test

The obtained test piece was measured for reflectance with an ultraviolet visible infrared spectrophotometer (manufactured by Nippon Bunko K.K.), and this value was used as an initial value. These test pieces were passed through a reflow furnace (peak temperature 255 DEG C) three times, and the reflectance was measured for each of the subsequent test pieces under the same conditions as the initial values to evaluate the deterioration state of each test piece. Also, each of the test pieces was evaluated visually.

The results of each test are shown in Table 2.

(2) Light resistance test

The obtained test piece was measured for reflectance with an ultraviolet visible infrared spectrophotometer (manufactured by Nippon Bunko K.K.), and this value was used as an initial value. These specimens were subjected to accelerated deterioration by irradiation with light of 120 J / cm 2 in a UV conveyor (output 120 W / cm, using a metal halide lamp and a cold mirror), and the reflectance was measured again as in the initial value. Also, each of the test pieces was evaluated visually.

The evaluation results are shown in Table 2.

In Table 2, the reflectance (Y value) is a value obtained by measuring the Y value of the XYZ color system with a spectroscopic colorimetric system, and the larger the value, the higher the reflectance. The values of L *, a * and b * in the L * a * b * colorimetric system are represented by color difference equations between two samples defined by? L *,? A * and? B * ).

ΔE * _ab = [(ΔL *) ² + (Δa *) ² + (Δb *) ² ] ^1/2 .

The smaller this value is, the smaller the deterioration of the coating film is. The evaluation criteria by the naked eye are as follows:?: No discoloration at all,?: No discoloration, but slight discoloration in comparison with the initial one, X: Apparent discoloration, XX: will be.

From the results shown in Table 2, the thermosetting resin composition of the present invention showed little change in the Y value of the reflectance in the heat resistance test and light resistance test, and showed less discoloration even in the naked eye evaluation.

Among them, the solder resist composition using the epoxy copolymer compound having no aromatic ring shown in Example 1 showed particularly little change in Y value.

As described above in detail, the solder resist formed by using the solder resist composition of the present invention has low discoloration due to light or heating over a long period of time, and is excellent in high reflectance.

Claims (5)

A thermosetting resin composition comprising (A) an epoxy compound having no aromatic ring, (B) a rutile titanium oxide, (C) a carboxyl group-containing resin, and (D)
The epoxy resin (A) having no aromatic ring is a copolymer resin having a weight average molecular weight of 3,000 to 100,000, which is obtained from a compound having an unsaturated double bond and a compound having an oxirane ring and an ethylenically unsaturated group in one molecule. By weight of the thermosetting resin composition. The thermosetting resin composition according to claim 1, wherein the epoxy compound (A) having no aromatic ring is an epoxy compound which is soluble in a liquid state or an organic solvent at room temperature. The thermosetting resin composition according to claim 1, wherein the carboxyl group-containing resin (C) has no aromatic ring. The thermosetting resin composition according to claim 1, further comprising a hindered phenolic compound. A printed wiring board characterized by having a cured product formed by using the thermosetting resin composition according to claim 1.