JP4538521B2 - Photocurable / thermosetting solder resist composition and printed wiring board using the same - Google Patents

Description

  The present invention is suitable for use as a permanent mask of a printed wiring board, and after exposure, an image can be formed by developing with an aqueous alkali solution, and then heat-cured to form a highly reflective solder resist film. The present invention relates to a photocurable / thermosetting solder resist composition and a printed wiring board obtained by forming a solder resist pattern on the surface of a printed wiring board on which a circuit is formed using the composition.

  A printed wiring board is generally formed by removing unnecessary portions of a copper foil bonded to a laminated board by etching to form circuit wiring, and electronic components are arranged at predetermined locations by soldering. For producing such a printed wiring board, a solder resist film is used. That is, the solder resist film is used as a protective film for a circuit when soldering an electronic component. The solder resist film prevents solder from adhering to unnecessary portions during soldering, and prevents the circuit conductor from being directly exposed to air and reacting with oxygen and moisture. Furthermore, it functions as a permanent protective film for the circuit board. Therefore, various properties such as adhesion, electrical insulation, solder heat resistance, solvent resistance, and chemical resistance are required.

  In addition, printed wiring boards have been increasingly miniaturized (finer), multilayered, and one-boarded to achieve higher density, and the mounting method has also shifted to surface mounting technology (SMT). Therefore, the demand for finer, high resolution, high accuracy, and high reliability of the solder resist film is also increasing.

  As a technique for forming such a solder resist pattern, an alkali developing type photoresist method is mainly used as a photoresist method capable of accurately forming a fine pattern, particularly in consideration of the environment.

  For example, in Japanese Patent Publication Nos. 1-54390 and 7-17737, a reaction product obtained by reacting a novolak type epoxy resin with an unsaturated monocarboxylic acid and further adding a polybasic acid anhydride is used as a base polymer. A liquid resist ink composition that can be developed with an aqueous alkaline solution is disclosed.

  On the other hand, in recent years, light-emitting diodes (LEDs) that emit light at low power, such as backlights for liquid crystal displays in portable terminals, personal computers, televisions, etc., and light sources for lighting fixtures, have been applied to printed wiring boards coated with solder resist films. Applications for direct mounting are increasing.

  Therefore, in order to efficiently use the light of the LED, there is a demand for a printed wiring board having a solder resist film that has high reflectivity and can increase the illuminance as a whole when the LED is mounted on the printed wiring board. .

  In order to efficiently use the light of the LED directly mounted on the printed wiring board, the solder resist film has a high reflectance as described above, and at the same time, this high reflectance is used during the period when the LED is used as a light source. You need to keep across. However, a general solder resist composition includes a component having an aromatic ring as one means for improving heat resistance. Here, the aromatic ring has a property of gradually reacting with light or heat, and the solder resist film formed by such a solder resist composition is gradually reacted with the aromatic ring during the period of mounting the LED. Has a problem of causing deterioration such as yellowing.

  An object of the present invention is to provide a white photo-curing / thermosetting solder resist composition capable of forming a high-reflectance solder resist film that is less susceptible to light degradation and heat degradation, and the white photo-curing / heat An object of the present invention is to provide a printed wiring board having a solder resist film having a high reflectance formed using a curable solder resist composition.

  As a result of diligent research, the present inventors have determined that the solder resist film is deteriorated (yellowing) by using a carboxyl group-containing resin having no aromatic ring, a hydrogenated epoxy compound, and rutile titanium oxide as a white pigment. It has been found that high reflectivity can be achieved over a long period of time.

  That is, according to the first aspect of the present invention, (A) a carboxyl group-containing resin having no aromatic ring, (B) a photopolymerization initiator, (C) a hydrogenated epoxy compound, (D) a rutile type titanium oxide. And (E) a white photocurable / thermosetting solder resist composition characterized by containing a diluent.

  According to another aspect of the present invention, a solder resist film is formed on the surface of a printed wiring board on which a circuit is formed using the white photocurable / thermosetting solder resist composition according to the first aspect. The resulting printed wiring board is provided.

  Hereinafter, the present invention will be described in more detail.

  The white solder resist composition of the present invention comprises (A) a carboxyl group-containing resin having no aromatic ring, (B) a photopolymerization initiator, (C) a hydrogenated epoxy compound, (D) a rutile-type titanium oxide, and (E) Contains a diluent.

As the carboxyl group-containing resin (A) not having an aromatic ring, a photosensitive carboxyl having at least one photosensitive unsaturated double bond in itself is a resin having a carboxyl group not having an aromatic ring. Either a group-containing resin or a carboxyl group-containing resin having no photosensitive unsaturated double bond can be used, and is not limited to a specific one. In particular, among the resins listed below, those having no aromatic ring (any of oligomers or polymers) can be preferably used. That is,
(1) Coordination of an aliphatic unsaturated carboxylic acid and an aliphatic polymerizable monomer having 2 to 20 carbon atoms (specifically, an aliphatic (meth) acryloyl compound, an aliphatic vinyl ether, a fatty acid vinyl ester, etc.) Carboxyl group-containing resin obtained by polymerization,
(2) A carboxyl group-containing (meth) acrylic copolymer resin produced from an aliphatic polymerizable monomer having 2 to 20 carbon atoms, and 4 to 20 carbon atoms having an oxirane ring and an ethylenically unsaturated group in one molecule. A photosensitive carboxyl group-containing resin obtained by reaction with an aliphatic polymerizable monomer of
(3) An aliphatic polymerizable monomer having 4 to 20 carbon atoms (for example, glycidyl (meth) acrylate) having one epoxy group and an unsaturated double bond in each molecule, and an unsaturated double bond The copolymer with an aliphatic polymerizable monomer having 2 to 20 carbon atoms (specifically, an aliphatic (meth) acryloyl compound, an aliphatic vinyl ether, a vinyl ester of a fatty acid, etc.) includes an aliphatic group. A photosensitive carboxyl group-containing resin obtained by reacting a saturated monocarboxylic acid and reacting the resulting secondary hydroxyl group with a saturated or unsaturated aliphatic polybasic acid anhydride,
(4) After reacting an aliphatic hydroxyl group-containing polymer with a saturated or unsaturated aliphatic polybasic acid anhydride, the resulting carboxylic acid has one epoxy group and one unsaturated double bond in each molecule. A photosensitive hydroxyl group- and carboxyl group-containing resin obtained by reacting an aliphatic polymerizable monomer having 4 to 20 carbon atoms (for example, glycidyl (meth) acrylate).
In the present specification, the term “aliphatic” includes a compound containing a cyclo ring such as a cyclohexane ring or a cyclohexene ring in the molecule.

  Among these, (a) a carboxyl group-containing (meth) acrylic copolymer resin produced from an aliphatic polymerizable monomer having 2 to 20 carbon atoms, which is the photosensitive carboxyl group-containing resin of (2) above, (B) A photosensitive carboxyl group-containing resin obtained by a reaction between an oxirane ring and an ethylenically unsaturated group-containing aliphatic polymerizable monomer having 4 to 20 carbon atoms in one molecule is preferable.

  The carboxyl group-containing (meth) acrylic copolymer resin produced from the (a) aliphatic polymerizable monomer having 2 to 20 carbon atoms is composed of (meth) acrylic acid ester having 4 to 20 carbon atoms and one molecule. It is obtained by copolymerizing one unsaturated group and an aliphatic compound having at least one carboxyl group. Examples of the (meth) acrylic acid ester constituting the copolymer resin (a) include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, hexyl ( Hydroxyl groups such as (meth) acrylic acid alkyl esters such as (meth) acrylate, 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, caprolactone-modified 2-hydroxyethyl (meth) acrylate Containing (meth) acrylic acid esters, methoxydiethylene glycol (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, isooctyloxydiethylene glycol (meth) acrylate, methoxy Triethylene glycol (meth) acrylate, glycol-modified (meth) acrylates such as methoxy polyethylene glycol (meth) acrylate. These may be used alone or in combination of two or more. In addition, in this specification, (meth) acrylate is a term that collectively refers to acrylate and methacrylate, and the same applies to other similar expressions.

  Examples of the aliphatic compound having one unsaturated group and at least one carboxyl group in one molecule include acrylic acid, methacrylic acid, and a modified unsaturated monocarboxylic acid having a chain extended between the unsaturated group and the carboxylic acid. Carboxylic acid, for example, β-carboxyethyl (meth) acrylate, 2-acryloyloxyethyl succinic acid, 2-acryloyloxyethyl hexahydrophthalic acid, unsaturated monocarboxylic acid having an ester bond due to lactone modification, etc., modification having an ether bond Examples thereof include unsaturated monocarboxylic acids and those containing two or more carboxyl groups in the molecule such as maleic acid. These may be used alone or in combination of two or more.

  (B) Examples of the aliphatic polymerizable monomer having 4 to 20 carbon atoms having an oxirane ring and an ethylenically unsaturated group in one molecule include glycidyl (meth) acrylate, α-methylglycidyl (meth) acrylate, 3, Examples include 4-epoxycyclohexylmethyl (meth) acrylate, 3,4-epoxycyclohexylethyl (meth) acrylate, 3,4-epoxycyclohexylbutyl (meth) acrylate, 3,4-epoxycyclohexylmethylamino acrylate, and the like. Among these, 3,4-epoxycyclohexylmethyl (meth) acrylate is preferable. These (b) C4-C20 aliphatic polymerizable monomers having an oxirane ring and an ethylenically unsaturated group in one molecule may be used alone or in admixture of two or more.

  The carboxyl group-containing resin (A) not having an aromatic ring needs to have an acid value in the range of 50 to 200 mgKOH / g. When the acid value is less than 50 mgKOH / g, it is difficult to remove the unexposed portion with a weak alkaline aqueous solution. When it exceeds 200 mgKOH / g, there are problems such as poor water resistance and electrical properties of the cured coating. Moreover, it is preferable that the weight average molecular weight of carboxyl group-containing resin (A) exists in the range of 5,000-100,000. When the weight average molecular weight is less than 5000, the dryness to touch tends to be extremely poor. On the other hand, if the weight average molecular weight exceeds 100,000, it is not preferable because developability and storage stability are remarkably deteriorated.

  Examples of the photopolymerization initiator (B) used in the present invention include benzoin and benzoin alkyl ethers such as benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether; acetophenone, 2,2-dimethoxy-2-phenyl Acetophenones such as acetophenone, 2,2-diethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone; 2-methyl-1- [4- (methylthio) phenyl]- 2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2- (dimethylamino) -2-[(4-methylphenyl) methyl ] -1- [4- (4-morpholinyl) Nenyl] -1-butanone and other aminoalkylphenones; 2-methylanthraquinone, 2-ethylanthraquinone, 2-tertiarybutylanthraquinone, 1-chloroanthraquinone and other anthraquinones; 2,4-dimethylthioxanthone, 2,4- Thioxanthones such as diethylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropylthioxanthone; ketals such as acetophenone dimethyl ketal and benzyldimethyl ketal; benzophenones such as benzophenone; or xanthones; (2,6-dimethoxybenzoyl)- 2,4,4-pentylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine Phosphine oxides such as oxide, ethyl-2,4,6-trimethylbenzoylphenyl phosphinate; various peroxides, titanocene initiators, and the like, which are N, N-dimethylaminobenzoic acid ethyl ester N, N-dimethylaminobenzoic acid isoamyl ester, pentyl-4-dimethylaminobenzoate, triethylamine, triethanolamine, and other photosensitizers such as triethanolamine may be used in combination. These photopolymerization initiators can be used alone or in combination of two or more.

  The blending amount of the photopolymerization initiator (B) is preferably 1 to 30 parts by mass, more preferably 2 to 25 parts by mass with respect to 100 parts by mass of the carboxyl group-containing resin (A) having no aromatic ring. When the blending amount of the photopolymerization initiator (B) is less than 1 part by mass, the photocurability is lowered, and pattern formation after exposure / development becomes difficult. On the other hand, when the amount exceeds 30 parts by mass, the thick film curability is lowered and the cost is increased.

  Next, the hydrogenated epoxy compound (C) is an epoxy obtained by nuclear hydrogenating a compound having an aromatic ring and then selectively hydrogenating the aromatic ring of the epoxidized compound and the aromatic epoxy compound. Any of the compounds can be used. For example, hydrogenated bisphenol A type epoxy resin, hydrogenated bisphenol F type epoxy resin, hydrogenated bisphenol S type epoxy resin, hydrogenated biphenol type epoxy resin, hydrogenated bixylenol type epoxy resin, hydrogenated phenol novolac type epoxy resin, water Hydrogenated aromatic glycidyl ether compounds such as hydrogenated cresol novolac type epoxy resins and hydrogenated bisphenol A type novolak type epoxy resins; Hydrogenated aromatic glycidyl ester compounds such as hydrogenated terephthalic acid diglycidyl ester; Known compounds such as hydrogenated aromatic glycidylamine compounds such as N, N ′, N′-tetraglycidylmetaxylenediamine and hydrogenated N, N-diglycidylaniline can be used. Among these, it is possible to use a hydrogenated bisphenol A type epoxy resin obtained by selectively nuclear hydrogenating an aromatic ring of a bisphenol A type epoxy resin (for example, trade name YX-8034 manufactured by Japan Epoxy Resin). From the viewpoint of electrical characteristics and heat resistance, it is more preferable. These hydrogenated epoxy compounds can be used alone or in combination of two or more.

In addition, as described above, in the case of an epoxy compound obtained by selectively hydrogenating an aromatic ring of an aromatic epoxy compound, the hydrogenation rate can be controlled, and the crystallinity and heat resistance can be controlled by the hydrogenation rate. , Heat degradation and the like will be different.
The average hydrogenation rate of the hydrogenated epoxy compound in the solder resist composition of the present invention is determined in consideration of suppressing deterioration of the solder resist film due to heat and maintaining good heat resistance. Specifically, the average hydrogenation rate is preferably 50 to 100%, more preferably 80 to 100%.

  The amount of the hydrogenated epoxy compound (C) is preferably 5 to 70 parts by mass, more preferably 5 to 60 parts by mass with respect to 100 parts by mass of the carboxy group-containing resin (A) having no aromatic ring. When the compounding amount of the hydrogenated epoxy compound (C) exceeds 70 parts by mass, the solubility of the unexposed part in the developer is lowered, the development residue tends to occur, and it is difficult to use practically. On the other hand, if the amount is less than 5 parts by mass, the carboxyl group of the carboxyl group-containing resin (A) remains in an unreacted state, and thus it is difficult to sufficiently obtain the electrical properties, solder heat resistance, and chemical resistance of the cured coating film. Tend to be.

  The carboxyl group of the carboxyl group-containing resin (A) having no aromatic ring reacts with the epoxy group of the hydrogenated epoxy compound (C) by ring-opening polymerization.

  In the present invention, one feature is that rutile titanium oxide (D) is used as the white pigment. Anatase-type titanium oxide is often used because of its high whiteness compared to the rutile type. However, since anatase-type titanium oxide has photocatalytic activity, it may cause discoloration of the resin in the solder resist composition. In contrast, rutile titanium oxide has a slightly lower whiteness than the anatase type, but has almost no photoactivity, so that a stable solder resist film can be obtained. As a rutile type titanium oxide (D), a well-known rutile type thing can be used. Specifically, TR-600, TR-700, TR-750, TR-840 manufactured by Fuji Titanium Industry Co., Ltd., R-550, R-580, R-630, R-820 manufactured by Ishihara Sangyo Co., Ltd., CR-50, CR-60, CR-90, KR-270, KR-310, KR-380, etc. manufactured by Titanium Industry Co., Ltd. can be used.

  The compounding amount of the rutile type titanium oxide (D) is preferably 50 to 300 parts by mass, more preferably 60 to 260 parts by mass with respect to 100 parts by mass of the carboxy group-containing resin (A) having no aromatic ring. . If the blending amount exceeds 300 parts by mass, the photocurability is lowered and the curing depth is lowered, which is not preferable. On the other hand, if it is less than 50 parts by mass, the hiding power is small, and a solder resist film having a high reflectance cannot be obtained.

  Moreover, in this invention, when a silica particle (F) is used together, the soldering resist composition which has a deeper hardening depth can be obtained. This is presumably because the refractive index of silica is relatively close to the carboxyl group-containing resin (A).

  Known silica particles (F) can be used. For example, spherical silica (Admafine SO-E1, SO-E2, SO-E5, etc. manufactured by Admatechs), finely divided silicon oxide, amorphous silica, crystalline silica, fused silica and the like can be mentioned. These silica particles can be used alone or in combination of two or more. The compounding amount of the silica particles (F) is preferably 50 to 200 parts by mass with respect to 100 parts by mass of the carboxy group-containing resin (A) having no aromatic ring.

  As a diluent (E) used by this invention, a photopolymerizable monomer and / or an organic solvent are mentioned. As photopolymerizable monomers, hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate and 2-hydroxybutyl acrylate; mono- or diacrylates of glycols such as ethylene glycol, methoxytetraethylene glycol, polyethylene glycol, propylene glycol; N, Acrylamides such as N-dimethylacrylamide and N-methylolacrylamide; aminoalkyl acrylates such as N, N-dimethylaminoethyl acrylate; hexanediol, trimethylolpropane, pentaerythritol, dipentaerythritol, tris-hydroxyethyl isocyanurate, etc. Polyhydric alcohols or polyhydric acrylates of these ethylene oxide or propylene oxide adducts Acrylates such as phenoxy acrylate, bisphenol A diacrylate and ethylene oxide or propylene oxide adducts of these phenols; acrylates of glycidyl ethers such as glycerin diglycidyl ether, trimethylolpropane triglycidyl ether; melamine acrylate; And / or methacrylates corresponding to the above acrylates.

  On the other hand, as organic solvents, 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 , Glycol ethers such as diethylene glycol monoethyl ether, dipropylene glycol monoethyl ether, triethylene glycol monoethyl ether; esters such as ethyl acetate, butyl acetate, cellosolve acetate, diethylene glycol monoethyl ether acetate and esterified products of the above glycol ethers Alcohols such as ethanol, propanol, ethylene glycol, propylene glycol; Mention may be made of petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, a petroleum solvent or the like, such as solvent naphtha; Tan, aliphatic hydrocarbons such as decane.

  The diluent (E) as described above can be used alone or as a mixture of two or more. It is preferable to use 20 to 300 parts by mass of the diluent (E) with respect to 100 parts by mass of the carboxyl group-containing resin (A) having no aromatic ring. The purpose of use of the diluent is to not only make the photopolymerizable monomer easy to apply, but also dilute the active energy ray-curable resin to enhance photopolymerization, while the organic solvent is This is because the film is formed by drying. Therefore, either a contact method or a non-contact exposure method in which the photomask is brought into contact with the coating film is used depending on the diluent used.

  Furthermore, in the white photocurable / thermosetting solder resist composition of the present invention, thermal degradation and photodegradation can be further reduced by containing an antioxidant and a hindered amine light stabilizer. The antioxidant is not particularly limited, but is preferably a hindered phenol compound. Examples of hindered phenol compounds include Nocrack 200, Nocrack M-17, Nocrack SP, Nocrack SP-N, Nocrack NS-5, Nocrack NS-6, Nocrack NS-30, Nocrack 300, Nocrack NS-7, Nocrack DAH. (All are manufactured by Ouchi Shinsei Chemical Co., Ltd.); MARK AO-30, MARK AO-40, MARK AO-50, MARK AO-60, MARK AO616, MARK AO-635, MARK AO-658, MARK AO -15, MARK AO-18, MARK 328, MARK AO-37 (all manufactured by Adeka Argus Chemical Co., Ltd.); Irganox 245, Irganox 259, Irganox 565, Irganox 1010, Irganox 1035, Irganox 1076, Irganox 1081, Irganox 1098, Irganox 1222, Irganox 1330, Irganox 1425WL (all of which are manufactured by Ciba Specialty Chemicals).

  Moreover, as a hindered amine light stabilizer, for example, Tinuvin 622LD, Tinuvin 144; CHIMASSORB 944LD, CHIMASSORB 119FL (all of these are manufactured by Ciba Specialty Chemicals); MARK LA-57, LA-62, LA-67, LA -63, LA-68 (all manufactured by Adeka Gas Chemical Co., Ltd.); Sanol LS-770, LS-765, LS-292, LS-2626, LS-1114, LS-744 (all above Sankyo Life) Tech Co., Ltd.).

  The antioxidant and light stabilizer are preferably added in an amount of 0.1 to 10 parts by mass with respect to 100 parts by mass of the carboxyl group-containing resin (A) having no aromatic ring.

  Furthermore, a curing accelerator, a thermal polymerization inhibitor, a thickener, an antifoaming agent, a leveling agent, a coupling agent, a flame retardant aid and the like can be used as necessary.

  The white photocurable / thermosetting solder resist composition of the present invention can be provided in a liquid or paste form.

  The white photocurable / thermosetting solder resist composition of the present invention is diluted as necessary to adjust the viscosity to be suitable for the coating method. This is applied to a printed wiring board on which a circuit is formed by a method such as a screen printing method, a curtain coating method, a spray coating method, or a roll coating method, and an organic solvent contained in the composition at a temperature of 70 to 90 ° C., for example. A tack-free coating film can be formed by evaporating and drying. Then, the printed wiring board of this invention can be obtained by exposing with an active energy ray selectively through a photomask, and developing an unexposed part with aqueous alkali solution, and forming a resist pattern. The alkaline aqueous solution used here is generally a 0.5 to 5 mass% aqueous sodium carbonate solution, but other alkaline use liquids can also be used. Examples of other alkaline aqueous solutions include alkaline aqueous solutions such as potassium hydroxide, sodium hydroxide, potassium carbonate, sodium phosphate, sodium silicate, ammonia, amines and the like. As an irradiation light source for exposure, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a xenon lamp, a metal halide lamp, or the like can be used. In addition, a laser beam can also be used as an actinic beam.

  In order to improve the heat resistance of the solder resist film thus obtained, it is desirable to secondarily cure the solder resist film with heat of 100 to 200 ° C., ultraviolet rays or far infrared rays.

The solder resist film formed using the solder resist composition of the present invention has high reflectivity, and may have good adhesion, heat resistance, solvent resistance and electrical properties required for the solder resist. all right. Further, the solder resist film formed according to the present invention maintains a high reflectance even after the accelerated deterioration test.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to this.

Synthesis of carboxyl group-containing resin having no aromatic ring A 2-liter separable flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel and a nitrogen introduction tube was charged with 900 g of diethylene glycol dimethyl ether as a solvent and t-as a polymerization initiator. 21.4 g of butyl peroxy 2-ethylhexanoate (Nippon Yushi Co., Ltd. perbutyl O) was added and heated to 90 ° C. After heating, 309.9 g of methacrylic acid, 116.4 g of methyl methacrylate, and 109.8 g of lactone-modified 2-hydroxyethyl methacrylate (Daicel Chemical Industries, Ltd., Plaxel FM1) were added to the bis ( 4-t-butylcyclohexyl) peroxydicarbonate (Perroyl TCP manufactured by Nippon Oil & Fats Co., Ltd.) was added dropwise over 3 hours, and further aged for 6 hours to obtain a carboxyl group-containing copolymer resin. It was. The reaction was performed under a nitrogen atmosphere.

  Next, 363.9 g of 3,4-epoxycyclohexylmethyl acrylate (Daicel Chemical Co., Ltd. Cyclomer A200), 3.6 g of dimethylbenzylamine as a ring-opening catalyst, polymerization inhibition were added to the obtained carboxyl group-containing copolymer resin. As an agent, 1.80 g of hydroquinone monomethyl ether was added, heated to 100 ° C., and stirred to carry out an epoxy ring-opening addition reaction. After 16 hours, a solution containing 53.8% by mass (nonvolatile content) of a carboxyl group-containing resin having no aromatic ring and 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-1 varnish.

Examples 1-3, Comparative Examples 1-4
Each component was blended and stirred according to Table 1 and dispersed with a three roll to obtain a solder resist composition. The numbers in the table indicate parts by mass.

R820: Rutile type titanium oxide KA-15 manufactured by Ishihara Sangyo Co., Ltd .: Anatase type titanium oxide YX-8034 manufactured by Titanium Industry Co., Ltd. Hydrogenated bisphenol A type epoxy resin manufactured by Japan Epoxy Resin HBPA: Hydrogenated bisphenol A type epoxy resin manufactured by Maruzen Petrochemical Co., Ltd. HBPA-DGE
YX-8300: Hydrogenated biphenyl type epoxy resin made by Japan Epoxy Resin TEPIC-H: β-form triglycidyl isocyanurate produced by Nissan Chemical Co., Ltd. TEPIC-S: α-form and β-form mixed triglycidyl isocyanurate produced by Nissan Chemical Co., Ltd. 828: Bisphenol A type SO-E5 made by Japan Epoxy Resin: Spherical silica initiator made by Admatech: Irgacure 907 made by Ciba Specialty Chemicals
Sensitizer: Nippon Kayaku DETX
Monomer: Dipentaeryth little hexaacrylate KS-66: Shin-Etsu silicone silicone oil Solvent: carbitol acetate

  In order to investigate various properties of a solder resist film formed using each solder resist composition, the test was conducted as follows and evaluated.

(1) Light resistance Each solder resist composition was 100 mm × 150 mm in size and 1.6 mm thick FR-4 copper-clad laminate by screen printing, 100 mesh polyester to a film thickness of 40 μm. It was printed with a solid plate using a bias plate and dried at 80 ° C. for 30 minutes in a hot air circulation drying oven. Using a HMW-680GW manufactured by Oak Manufacturing Co., Ltd. for printed wiring board, UV exposure was performed with an integrated light amount of 500 mJ / cm ² so as to leave a 30 mm square negative pattern, and a 1% sodium carbonate aqueous solution was developed at 30 ° C. As described above, development was performed with a developing machine for printed wiring boards for 60 seconds, followed by heat curing at 150 ° C. for 60 minutes in a hot-air circulating drying furnace to prepare test pieces for characteristic tests.

The obtained test piece was measured with Minolta color difference meter CR-400. Thereafter, UV light was applied to a UV conveyor furnace (output: 150 W / cm 2 metal halide lamp, cold mirror) 150 J / cm ² to cause accelerated light degradation. The results are shown in Table 2.

In Table 2, Y represents the reflectance of the XYZ color system, ^{L * represents} the L ^* a * ^{b *} lightness color system. a ^* indicates the red direction, -a ^* indicates the green direction, b ^* indicates the yellow direction, and -b ^* indicates the blue direction. The closer to zero, the lower the saturation. ΔE ^* ab indicates a change in color. A smaller value indicates a smaller color change. As for the visual evaluation items, the double circle shows no discoloration, the circle shows almost no discoloration, the triangle shows some discoloration, and the cross indicates clear discoloration.

Comparative Example 4 contains anatase type titanium oxide instead of rutile type titanium oxide. As is apparent from Table 2, the anatase-type titanium oxide has a high initial reflectivity, but after accelerated light deterioration, both the reflectivity Y and the lightness L ^* are greatly reduced, and the ΔE ^* ab value, which is a color change, is also large. . Moreover, discoloration is seen also in visual evaluation. From this, it was found that rutile type titanium oxide is superior as a solder resist composition component having high reflectivity than anatase type titanium oxide.

(2) Heat resistance Each test piece produced in the same manner as in (1) was measured with a color difference meter CR-400 manufactured by Minolta. Subsequently, in a hot air circulation type drying furnace, it was accelerated and deteriorated by heating at 150 ° C. for 500 hours and 1000 hours. The results are shown in Table 3.

As is apparent from Table 3, in Examples 1 to 3 using the composition of the present invention, even after accelerated deterioration, the reflectance does not decrease, the change in brightness is small, and ΔE ^* ab which is a color change It can be seen that the value of is small. In addition, there is no or almost no discoloration by visual evaluation.

Comparative Examples 1 to 3 use an epoxy compound other than a hydrogenated epoxy compound. As can be seen from Table 3, in the composition containing the epoxy compound other than the hydrogenated epoxy compound in the solder resist composition, both the reflectance Y and the lightness L ^* are greatly reduced after accelerated thermal degradation, and The value of ΔE ^* ab, which is a change, is also large. Moreover, discoloration is recognized also in visual evaluation. From this, it is understood that when an epoxy compound other than the hydrogenated epoxy compound is used in the resin in the solder resist composition, the solder resist film is deteriorated by heat.

(3) Solvent resistance Each test piece prepared in the same manner as in (1) was dipped in propylene glycol monomethyl ether acetate for 30 minutes and dried, and then a peel test with a cellophane adhesive tape was performed to peel and discolor the coating film. Was evaluated. The results are also shown in Table 4. Here, the circle mark indicates that there was no peeling or discoloration of the coating film, and the cross mark indicates that there was peeling or discoloration of the coating film.

(4) Pencil hardness test A B to 9H pencil sharpened so that the tip of the core is flattened against each test piece prepared in the same manner as in (1) at an angle of about 45 ° to form a coating film The hardness of the pencil where no peeling occurred was recorded. The results are also shown in Table 4.

(5) Insulation resistance test A test piece was prepared under the same conditions as in (1) except that a comb-type electrode B coupon having an IPC B-25 test pattern was used instead of the FR-4 copper-clad laminate. A DC 500 V bias was applied to the test piece, and the insulation resistance value was measured. The results are also shown in Table 4.

  As is clear from Table 4, in Examples 1 to 3 using the solder resist composition of the present invention, the solder resist film has good heat resistance, solvent resistance, adhesion and electrical insulation required. I understood it.

  As described in detail above, according to the present invention, a photocurable / thermosetting white solder resist composition capable of forming a solder resist film having a high reflectance can be obtained. The high-reflectance solder resist film formed from the solder resist composition of the present invention is resistant to light deterioration and heat deterioration and can withstand long-term use.

Claims (8)

  (A) a carboxyl group-containing resin having no aromatic ring, (B) a photopolymerization initiator, (C) a hydrogenated epoxy compound, (D) a rutile-type titanium oxide, and (E) a diluent. A white photocurable / thermosetting solder resist composition.   The white carboxyl group-containing resin according to claim 1, wherein the carboxyl group-containing resin (A) having no aromatic ring is a carboxyl group-containing resin produced from an aliphatic polymerizable monomer having 2 to 20 carbon atoms. Photo-curable / thermosetting solder resist composition.   The carboxyl group-containing resin (A) having no aromatic ring is (a) a carboxyl group-containing (meth) acrylic copolymer resin produced from an aliphatic polymerizable monomer having 2 to 20 carbon atoms, and (b) The copolymer resin having a carboxyl group obtained by a reaction of an oxirane ring and an aliphatic polymerizable monomer having 4 to 20 carbon atoms having an ethylenically unsaturated group in one molecule. The white photocurable / thermosetting solder resist composition described.   The hydrogenated epoxy compound (C) is a hydrogenated bisphenol A type epoxy resin obtained by selectively nuclear hydrogenating an aromatic ring of an aromatic epoxy compound. The white photocurable thermosetting solder resist composition according to one item.   The photocurable / thermosetting solder resist composition according to any one of claims 1 to 4, wherein the amount of the photopolymerization initiator (B) is a carboxyl group containing no aromatic ring. It is 1-30 mass parts with respect to 100 mass parts of resin (A), and the compounding quantity of the said hydrogenated epoxy compound (C) is with respect to 100 mass parts of carboxyl group-containing resin (A) which does not have the said aromatic ring. 5 to 70 parts by mass, and the amount of the rutile titanium oxide (D) is 50 to 300 parts by mass with respect to 100 parts by mass of the carboxy group-containing resin (A) having no aromatic ring, And the white photocuring characterized by the compounding quantity of the said diluent (E) being 20-300 mass parts with respect to 100 mass parts of carboxyl group-containing resin (A) which does not have the said aromatic ring. And thermosetting solder resist composition.   (F) The white photocurable thermosetting solder resist composition according to any one of claims 1 to 5, further comprising silica particles.   The blending amount of the silica particles (F) is 50 to 200 parts by mass with respect to 100 parts by mass of the carboxy group-containing resin (A) not having the aromatic ring. White photo-curing / thermosetting solder resist composition.   Printed wiring obtained by forming a solder resist film on the surface of a printed wiring board on which a circuit is formed using the white photocurable / thermosetting solder resist composition according to any one of claims 1 to 7. Board.