WO2008050768A1

WO2008050768A1 - Photocurable/thermocurable solder resist composition, and printed circuit board using the same

Info

Publication number: WO2008050768A1
Application number: PCT/JP2007/070654
Authority: WO
Inventors: Yoshikazu Daigo; Shigeru Ushiki
Original assignee: Taiyo Ink Mfg. Co., Ltd.
Priority date: 2006-10-24
Filing date: 2007-10-23
Publication date: 2008-05-02
Also published as: TWI357536B; CN101356475A; KR20090068305A; CN101356475B; JPWO2008050768A1; KR101002902B1; TW200834233A; JP4538521B2

Abstract

Disclosed is a white-colored photocurable and thermocurable solder resist composition which enables to form a highly reflective solder resist film that is hardly deteriorated by light or heat. Also disclosed is a printed circuit board having a highly reflective solder resist film formed by using the white-colored photocurable and thermocurable solder resist composition.

Description

Specification

Photocuring / thermosetting solder resist composition and printed wiring board using the same

Technical field

[0001] The present invention is suitable for use as a permanent mask of a printed wiring board. After exposure, an image is formed by developing with an alkaline aqueous solution, and then heat-cured to form a high-reflectance solder resist film. The present invention relates to a photocurable / thermosetting solder resist composition that can be formed, 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.

Background art

[0002] A printed wiring board is generally formed by removing unnecessary portions of a copper foil bonded to a laminated board by etching to form a circuit wiring. Electronic components are arranged at predetermined locations by soldering. Yes. A solder resist film is used for manufacturing such a printed wiring board. That is, the solder resist film is used as a protective film for circuits when soldering electronic components. The solder resist film prevents solder from adhering to unnecessary parts during soldering and prevents the circuit conductor from being exposed directly to air and reacting with oxygen and moisture. It also functions as a permanent protective film for circuit boards. Therefore, various properties such as adhesion, electrical insulation, solder heat resistance, solvent resistance, and chemical resistance are required.

[0003] In addition, printed wiring boards have been increasingly miniaturized (finer), multilayered, and made into one board to achieve higher density, and the mounting method has also shifted to surface mounting technology (SMT). ing. Therefore, the demand for finer, higher resolution, higher accuracy, and higher reliability is increasing for solder resist films.

[0004] As a technique for forming such a solder resist pattern, the alkali developing type photoresist method has become the mainstream because of the photoresist method that can accurately form fine patterns, especially environmental considerations! /

[0005] For example, Japanese Patent Publication No. 1 54390 and Japanese Patent Publication No. 7-17737 contain nopolak-type Epoch There has been disclosed a liquid resist ink composition which can be developed with an aqueous alkali solution based on a reaction product obtained by reacting an unsaturated resin with an unsaturated monocarboxylic acid and further adding a polybasic acid anhydride.

[0006] On the other hand, in recent years, solder resist films have been formed on light emitting diodes (LEDs) that emit light at low power, such as backlights for liquid crystal displays of portable terminals, personal computers, televisions, etc., and light sources for lighting fixtures. Applications for mounting directly on printed wiring boards are increasing.

[0007] Therefore, in order to efficiently use the light of the LED, there is 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. It has been demanded.

[0008] In order to efficiently use the light of the LED mounted directly on the printed wiring board, the solder resist film has a high reflectance as described above, and at the same time, the LED is used as a light source for the LED. It needs to be kept over the period of use. 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 sono-redder resist composition is gradually used during the LED mounting period. There is a problem that the reaction causes deterioration such as yellowing.

Disclosure of the invention

[0009] An object of the present invention is to provide a white photocurable / thermosetting solder resist composition capable of forming a highly reflective solder resist film that is less susceptible to light degradation and heat degradation, and the white An object of the present invention is to provide a printed wiring board having a solder resist film having a high reflectivity formed by using a photocurable / thermosetting solder resist composition.

As a result of diligent research, the present inventors have found that the use of a carboxyl group-containing resin having no aromatic ring, a hydrogenated epoxy compound, and rutile-type titanium oxide as a white pigment has caused deterioration of the solder resist film (yellow We have found that it is possible to achieve high reflectivity over a long period of time, with the power S.

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) Rutile titanium oxide, and (E) a white photo-curing / thermosetting solder resist characterized by containing a diluent A composition is provided.

[0012] 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 has been formed using the white photocurable / thermosetting solder resist composition according to the first aspect. A printed wiring board obtained by forming is provided.

BEST MODE FOR CARRYING OUT THE INVENTION

[0013] Hereinafter, the present invention will be described in more detail.

[0014] 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 oxidation. Titanium, and (E) a diluent.

[0015] No aromatic ring! /, Carboxyl group-containing resin (A) includes an aromatic ring! /, A resin having a carboxy group, which itself has a photosensitive unsaturated double bond. Either a photosensitive carboxyl group-containing resin having one or more bonds 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) An aliphatic unsaturated carboxylic acid and an aliphatic polymerizable monomer having 2 to 20 carbon atoms (specifically, an aliphatic (meth) attalyloyl compound, an aliphatic butyl ether, a butyl ester of a fatty acid, etc.) A carboxyl group-containing resin obtained by copolymerization,

(2) A carboxyl group-containing (meth) acrylic copolymer resin produced from an aliphatic polymerizable monomer having 2 to 20 carbon atoms, and an oxysilane ring and an ethylenically unsaturated group in one molecule. A photosensitive carboxyl group-containing resin obtained by reaction with 20 aliphatic polymerizable monomers;

(3) An aliphatic polymerizable monomer having 4 to 20 carbon atoms each having one epoxy group and an unsaturated double bond in one molecule (for example, glycidyl (meth) acrylate), and unsaturated double Examples of the copolymer with an aliphatic polymerizable monomer having 2 to 20 carbon atoms having a bond (specifically, an aliphatic (meth) attalyloyl compound, an aliphatic butyl ether, a fatty butyl ester, etc.). A photosensitivity obtained by reacting an aliphatic unsaturated monocarboxylic acid and reacting the resulting secondary hydroxyl group with a saturated or unsaturated aliphatic polybasic acid anhydride. Functional carboxyl group-containing resin,

(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 an unsaturated double in each molecule. Photosensitive hydroxyl group and carboxyl group-containing resin obtained by reacting an aliphatic polymerizable monomer having 4 to 20 carbon atoms having a bond (for example, glycidyl (meth) acrylate).

It is.

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

[0017] The carboxyl group-containing (meth) acrylic copolymer resin (a) produced from an aliphatic polymerizable monomer having 2 to 20 carbon atoms includes (meth) acrylic acid ester having 4 to 20 carbon atoms, and 1 It is obtained by co-polymerizing an aliphatic compound having one unsaturated group and at least one carboxyl group in the molecule. 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) ) (Meth) acrylic acid alkyl esters such as acrylate, hexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, hydroxy pill (meth) acrylate, hydroxybutyl (meth) acrylate , Force Prolataton Modified 2-Hydroxy Shetyl (Meth) acrylate (hydroxy) -containing (meth) acrylic esters, methoxy diethylene glycol (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, isooctyloxy diethylene glycol (meta ) Atarylate, methoxytri Examples include glycol-modified (meth) acrylates such as ethylene glycol (meth) acrylate and methoxypolyethylene glycol (meth) acrylate. These may be used alone or in admixture of two or more. In the present specification, (meth) arylate refers to It is a term that collectively refers to talates and meta acrylates, and the same applies to other similar expressions.

[0018] Further, as an aliphatic compound having one unsaturated group and at least one carboxyl group in one molecule, acrylic acid, methacrylic acid, or a modified chain in which the chain between the unsaturated group and the carboxylic acid is extended. Unsaturated monocarboxylic acids such as / 3-carboxyethyl (meth) acrylate, 2-acids, unsaturated monocarboxylic acids having ester bonds due to rataton modification, etc., modified unsaturated monocarboxylic acids having ether bonds, Examples include those containing two or more carboxyl groups such as maleic acid in the molecule. These may be used alone or in combination of two or more.

[0019] (b) Examples of aliphatic polymerizable monomers having 4 to 20 carbon atoms having an oxysilane ring and an ethylenically unsaturated group in one molecule include glycidyl (meth) acrylate and a-methyl darisidinole (meth) Atalylate, 3, 4-Epoxycyclohexylmethyl (meth) acrylate, 3, 4— Epoxy cyclohexylenoretinore (meth) acrylate, 3, 4-Epoxycyclohexenolevyl (meth) acrylate, 3, 4— The ability to mention epoxy cyclohexyl methyl amino acrylate etc. Of these, 3,4-epoxycyclohexylmethyl (meth) acrylate is preferred. These (b) aliphatic polymerizable monomers having 4 to 20 carbon atoms having an oxysilane ring and an ethylenically unsaturated group in one molecule may be used alone or in admixture of two or more.

Yes

[0020] The carboxyl group-containing resin (A) having no aromatic ring needs to have an acid value in the range of 50 to 200 mg KO H / g. When the acid value is less than 50 mgKOH / g, it is difficult to remove the unexposed area with a weak alkaline aqueous solution. If it exceeds 200 mgKOH / g, there are problems such as poor water resistance and electrical properties of the cured film. The weight average molecular weight of the carboxyl group-containing resin (A) is preferably in the range of 5,000-100,000. If 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.

[0021] Examples of the photopolymerization initiator (B) used in the present invention include benzoin and benzoin Benzoin such as chinoleatenore, benzoinethinoleethenole, benzoinisopropinoleethenole, and benzoinanolenoquineateoles; acetophenone, 2,2-dimethoxy-2-phenyl dirucetophenone, 2,2-diethoxy-2-phenyl Acetophenone, 2, 2-diethoxy —2-phenylacetophenone, 1,1-dichloroacetophenone and other acetophenones; 2-methyl-1 [4 (methylthio) phenyl] -2-morpholinopropane 1-on, 2 — Benzyl-2 dimethylamino 1- (4 morpholinophenyl) -butanone 1, 2-— (dimethylamino)-2- [(4 methylphenyl) methyl] 1 [4 mono (4-morpholinyl) phenyl] 1-butanone and other aminoalkyls Phenones; 2-methylanthraquinone, 2-ethyl anthraquinone, 2-ta Anthraquinones such as Shary butyl anthraquinone and 1 black mouth anthraquinone; Thioxanthones such as 2, 4 dimethylthioxanthone, 2, 4 jetyl thioxanthone, 2 black mouth thixanthone, 2, 4 diisopropylthioxanthone; Acetofenone dimethyl ketal, benzyl dimethyl ketal Benzophenones such as benzophenone; or xanthones; (2, 6 dimethoxybenzoyl) 2, 4, 4 pentylphosphine oxide, bis (2, 4, 6 trimethylbenzoyl) phenylphosphine Phosphine oxides such as oxide, 2, 4, 6 trimethylbenzoyldiphenyl phosphine oxide, ethyl 2, 4, 6 trimethyl benzoyl phenyl phosphinate; various peroxides, titanocene initiators, etc. Cited These are photosensitizers such as tertiary amines such as N, N dimethylaminobenzoic acid ethyl ester, N, N dimethylaminobenzoic acid isoamyl ester, pentyl-4-dimethylaminobenzoate, triethinoreamine, triethanolamine and the like. You may use together with a sensitizer etc. These photopolymerization initiators can be used alone or in combination of two or more.

[0022] The amount of the photopolymerization initiator (B) is preferably no aromatic ring! /, Preferably 1 to 30 parts by mass, more preferably 2 parts per 100 parts by mass of the carboxyl group-containing resin (A). ~ 25 parts by weight. 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, as the hydrogenated epoxy compound (C), a compound having an aromatic ring is subjected to nuclear hydrogenation, and then the epoxidized compound and the aromatic ring of the aromatic epoxy compound are selectively subjected to nuclear hydrogenation. Any of the epoxy compounds obtained 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 nopolac Type epoxy resin, hydrogenated cresol nopolac type epoxy resin, hydrogenated bisphenol A type nopolac type epoxy resin and other hydrogenated aromatic darisidyl ether compounds; hydrogenated terephthalic acid diglycidyl ester and other hydrogenated aromatic types Glycidyl ester compounds; hydrogenated N, N, Ν ', Ν, monotetraglycidyl metaxylene diamine, hydrogenated Ν, Ν-diglycidyl adiline and other hydrogenated aromatic glycidyl amine compounds Can be used. Among these, hydrogenated bisphenol A type epoxy resin (for example, trade name YX-8034 manufactured by Japan Epoxy Resin Co., Ltd.) obtained by selectively nuclear hydrogenating the aromatic ring of bisphenol Α type epoxy resin. It is more preferable to use from the viewpoint of electrical characteristics and heat resistance. These hydrogenated epoxy compounds can be used alone or in combination of two or more.

[0024] As described above, in the case of an epoxy compound obtained by selectively nuclear hydrogenating an aromatic ring of an aromatic epoxy compound, the hydrogenation rate can be controlled, and the hydrogenation rate can be reduced. Crystallinity, heat resistance, heat degradation, etc. are 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%.

[0025] The amount of the hydrogenated epoxy compound (C) is preferably 5 to 70 parts by mass, more preferably 5 to 70 parts by mass with respect to 100 parts by mass of the carboxy group-containing resin (A) without having an aromatic ring! 60 parts by mass. When the blending amount of the hydrogenated epoxy compound (C) exceeds 70 parts by mass, the solubility of the unexposed part in the developer is lowered, and development residue tends to occur, making it 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, so that the cured coating has sufficient electrical properties, solder heat resistance, and chemical resistance. It tends to be difficult.

[0026] A resin having an aromatic ring, a carboxyl group of the carboxyl group-containing resin (A), and a hydrogenated epoxy resin It reacts with the epoxy group of the compound (C) by ring-opening polymerization.

[0027] One feature of the present invention 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 type titanium oxide has a slightly lower whiteness than anatase type, but has almost no photoactivity, so that a stable solder resist film can be obtained. As the rutile type titanium oxide (D), a known rutile type 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 manufactured by Titanium Industry Co., Ltd. can be used.

[0028] The amount of the rutile-type titanium oxide (D) is preferably 50 to 300 parts by mass, more preferably 60 parts per 100 parts by mass of the carboxy group-containing resin (A) without having an aromatic ring! ~ 260 parts by mass. 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 the amount is less than 50 parts by mass, it is impossible to obtain a solder resist film having a high reflectivity with a small hiding power.

In the present invention, when the silica particles (F) are used in combination, a solder resist composition having a deeper curing depth can be obtained. This is probably because the refractive index of silica is relatively close to that of the carboxyl group-containing resin (A).

[0030] Known silica particles (F) can be used. For example, spherical silica (Admafine SO-El, SO-E2, SO-E5, etc. manufactured by Admatechs), fine powdered 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.

[0031] Examples of the diluent (E) used in the present invention include a photopolymerizable monomer and / or an organic solvent strength S. Examples of the photopolymerizable monomer include 2-hydroxyethyl acrylate, 2-hydroxyethyl tert-oleate, 2-hydroxyethyl acrylate, and ethylene glycolate. Mono- or diatalylates of glycols such as methoxytetraethylene glycol, polyethylene glycol, propylene glycol; acrylamides such as N, N-dimethylacrylamide, N-methylolacrylamide; amino such as N, N-dimethylaminoethyl acrylate Alkyl acrylates; polyhydric alcohols such as hexanediol, trimethylolpropane, pentaerythritol, dipentaerythritol, tris-hydroxyethyl isocyanurate, or polyvalent acrylates of these ethylene oxide or propylene oxide adducts; Athenates such as phenoxy acrylate, bisphenol A diathalate and ethylene oxide or propylene oxide adducts of these phenols Examples thereof include talidates of glycidyl ethers such as glycerol serine glycidyl ether and trimethylolpropane triglycidyl ether; melamine attalylate; and / or metatalylates corresponding to the attalylates.

[0032] On the other hand, examples of the organic solvent include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as tonolene, xylene and tetramethylbenzene; methyl cetosolve, ethinorecerosonolev, Butinorecero Sonoreb, Metinorecanorebitonore, Butinorecanolebitonore, Propylene Glyconore Monomethenoreatenore, Diethylene Glycolic Monoremonotinoreatenore, Dipropren Glico Reno Mononoreinore Glycol ethers such as tenole and triethyleneglycolenoethylenoate ether; esters such as ethyl acetate, butyl acetate, cellosolve acetate, diethyleneglycolenomonoethylenoate acetate, and esterified products of the above glycolenoate noles Class: Ethanore, Propano Alcohols such as ethylene glycol, propylene glycol; octane, aliphatic hydrocarbons such as decane; leaves with petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and force S include petroleum solvents such as such as solvent naphtha.

[0033] The diluent (E) as described above may be used alone or as a mixture of two or more. Carboxy group-containing resin having no aromatic ring (A) It is preferable to use 20 to 300 parts by weight of diluent (E) with respect to 100 parts by weight of resin. The purpose of use of the diluent is to increase the photopolymerizability of the photopolymerizable monomer by diluting the active energy ray curable resin that is easy to apply! This is because the organic solvent is formed into a film by drying. Therefore, depending on the diluent used, contact the photomask with the coating. The contact method to be used is a non-contact type! /, Or a misalignment exposure method.

[0034] Further, in the white photocurable 'thermosetting solder resist composition of the present invention, by containing an antioxidant and a hindered amine light stabilizer, thermal degradation and photodegradation can be further reduced. it can. The antioxidant is not particularly limited. 1S is preferably a hindered phenol compound. The hindered phenolic compounds are: Nocrack 200, Nocrack Μ—17, Nocrack SP, Nocrack SP—N, Nocrack NS—5, Nocrack NS—6, Nocrack NS—30, Nocrack 300, Nocrack NS-7, NOCRACK DAH (all of which are manufactured by Ouchi Shinsei Chemical Co., Ltd.); MARK AO-30, M ARK AO-40, MARK AO-50, MARK AO-60, MARK A0616, MA RK AO-635 , MARK AO—658, MARK AO—15, MARK AO—18, M ARK 328, MARK AO—37 (all manufactured by Adeka Gas Chemical Co., Ltd.); Irga Knox 245, Irganox 259, Irganox 565, Irganox 1010, Irganock Tas 1035, Inoreganox 1076, Inoreganox 1081, Inoreganox 1098, Inoreganox 1222, Inoreganox 1330, Irganox 1425WL (all above 'Chemical Co., Ltd.) and the like.

[0035] The hindered amine light stabilizers include, for example, Tinuvin 622LD, Tinuvin 14 4; CHIMASSORB 944LD, CHIMASSORB 119FL (all of which are manufactured by Chinoku Specialty Chemicals); MARK LA-57, LA— 62, LA-67, LA-63, LA-68 (all manufactured by Adeka Gas Chemical Co., Ltd.); Sanonore LS-770, LS-765, LS-292, LS-2626 ,: LS-1114, LS- 744 (above! /, The deviation is made by Sankyo Life Tech Co., Ltd.).

[0036] The antioxidant and the light stabilizer preferably have no aromatic ring! /, And are added in an amount of 0 .;! To 10 parts by mass with respect to 100 parts by mass of the carboxyl group-containing resin (A).

[0037] 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.

[0038] The white photocurable / thermosetting solder resist composition of the present invention can be provided in the form of a liquid or paste.

[0039] If necessary, the white photocurable / thermosetting solder resist composition of the present invention may be diluted. And adjust to a viscosity suitable for the application method. This is applied to a printed circuit board on which a circuit is formed by a method such as screen printing, curtain coating, spray coating, roll coating, etc., and is 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 the organic solvent. Thereafter, the printed wiring board of the present invention can be obtained by selectively exposing with an active energy ray through a photomask and developing the unexposed portion with an alkaline aqueous solution to form a resist pattern. The alkaline aqueous solution used here is generally 0.5 to 5% by mass of sodium carbonate aqueous solution, but other alkaline use liquids can also be used. Examples of other aqueous alkaline solutions include alkaline aqueous solutions such as potassium hydroxide, sodium hydroxide, potassium carbonate, sodium phosphate, sodium silicate, ammonia, and amines. As an irradiation light source for exposure, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, a super-high pressure mercury lamp, a xenon lamp, a metal lamp, a ride lamp, or the like can be used. In addition, a laser beam can be used as an actinic beam.

[0040] 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 20 ° C, ultraviolet rays or far infrared rays.

[0041] The solder resist film formed using the solder resist composition of the present invention has a high reflectivity, and has good adhesion, heat resistance, solvent resistance and electrical properties required for the solder resist. It was found to have Further, the solder resist film formed according to the present invention maintains a high reflectance even after the accelerated deterioration test.

Example

[0042] Hereinafter, the present invention will be described with reference to examples. The present invention is not limited thereto.

Yes

[0043] No aromatic ring! / Synthesis of carboxyl group-containing resin

In a 2 liter separable flask equipped with a stirrer, thermometer, reflux condenser, dropping funnel and nitrogen introduction tube, 900 g of diethylene glycol dimethyl ether as a solvent and t-butylperoxy 2-ethylhexanoate as a polymerization initiator (Nippon Yushi Co., Ltd.) Pouch chinole made by O) 2) C heated up. After calo heat, here is methacrylolic acid 309 · 9g , 116.4 g of methylol methacrylate, and 19.8 g of rataton-modified 2-hydroxyethyl methacrylate (Daicel Chemical Industries Plaxel FM1) 109.8 g of bis (4-tert-butylcyclohexyl) peroxy Carboxyl group-containing copolymer resin was obtained by adding dropwise over 3 hours together with 21.4 g of dicarbonate (Nippon Yushi Co., Ltd. Parroyl TCP) and aging for 6 hours. The reaction was performed under a nitrogen atmosphere.

[0044] Next, to the obtained carboxyl group-containing copolymer resin, 36,9 g of 3,4-epoxycyclohexyl methyl acrylate (Cyclomer A200, manufactured by Daicel Chemical Industries, Ltd.), dimethylbenzyl as a ring-opening catalyst Addition of 3.6 g of amine and 1.80 g of hydroquinone monomethyl ether as a polymerization inhibitor, followed by heating to 100 ° C. and stirring to carry out epoxy ring-opening addition reaction. After 16 hours, a solution containing 53.8% by mass (non-volatile content) of a carboxyl group-containing resin having no aromatic ring and having an acid value of solids of 108.9 mgKOH / g and a weight average molecular weight of 25,000 is obtained. It was. Hereinafter, this reaction solution is referred to as A-1 varnish.

[0045] Examples;! To 3, Comparative examples;! To 4

Each component was blended according to Table 1 and stirred to disperse it with a three roll to obtain a solder resist composition. The numbers in the table indicate parts by mass.

[table 1]

1

Examples Examples Examples Examples Comparative Examples Comparative Examples Comparative Examples Comparative Examples 1 2 3 1 2 3 4

A-1 Varnish 186 186 186 186 186 186 186

R820 180 180 180 180 180 180

KA-15 180

YX-8034 37 37

HBPA 37

YX-8300 37

TEP1C-H 19

TEP1C-S 19

828 37

SO-E5 1 10 1 10 110 110 1 10 110 110 Initiator 19 19 19 19 19 19 19 Sensitizer 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Monomer 15 15 15 15 15 15 15

KS-66 3 3 3 3 3 3 3 Solvent 20 20 20 20 20 20 20 [0046] R820: Rutile titanium oxide manufactured by Ishihara Sangyo Co., Ltd.

KA-15: Anatase type titanium oxide manufactured by Titanium Industry Co., Ltd.

YX-8034: Hydrogenated bisphenol A type epoxy resin made by Japan Epoxy Resin

HBPA: Maruzen Petrochemical Hydrogenated Bisphenol A Type Epoxy Resin HBPA—DGE

YX— 8300: Hydrogenated biphenyl type epoxy resin made by Japan Epoxy Resin

TEPIC-H: Nissan Chemical Co., Ltd./3 body triglycidyl isocyanurate

TEPIC-S: Nissan Chemical Co., Ltd. α- and 0-body mixed triglycidyl isocyanurate 82

8: Japan Epoxy Resin Bisphenol

SO-E5: Admatech spherical silica

Initiator: INOREGACURE 907 manufactured by Ciba Specialty Chemicals

Sensitizer: Nippon Kayaku DETX

Monomer: Dipentaerythritol Hexatalylate

KS-66: Shin-Etsu Silicone Silicone Oil

Solvent: carbitol acetate.

[0047] In order to examine various properties of a solder resist film formed using each solder resist composition, the test was conducted as follows.

[0048] (1) Light resistance

Each sono-redder resist yarn composition is 100 mm XI 50 mm in size and a 1.6 mm thick FR-4 copper clad laminate is screen printed to a 100 mesh polyester to a film thickness of 40 m. 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 an HMW-680GW manufactured by Oak Manufacturing Co., Ltd. for printed wiring boards, UV exposure is performed with a cumulative light intensity of 500 mj / cm ² so that a 30 mm square negative pattern remains, and a 1% sodium carbonate aqueous solution at 30 ° C As a developer, development was carried out for 60 seconds with a developing machine for printed wiring boards, followed by thermosetting at 150 ° C. for 60 minutes in a hot-air circulating drying furnace to prepare test pieces for characteristic tests.

[0049] The obtained test piece was measured with a color difference meter CR-400 manufactured by Minolta. The UV conveyor furnace (output 150W / cm metal halide lamp, cold mirror) was irradiated with 150j / cm ² of light to cause accelerated light degradation. The results are shown in Table 2. [Table 2]

Table 2

[0050] In Table 2, Y represents the reflectance of the XYZ color system, and L * represents the lightness of the L * a * 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, there is no saturation. A E * ab indicates a color change. The smaller this value, the smaller the color change. Regarding visual evaluation items, double circles show no discoloration, circles show almost no discoloration, triangles show slight discoloration, and back marks show clear discoloration.

[0051] Comparative Example 4 contains anatase type titanium oxide instead of rutile type titanium oxide. As is clear from Table 2, anatase-type titanium oxide has a high initial reflectivity, but after accelerated light degradation, both reflectivity Y and lightness L * are greatly reduced, and the color change AE * ab value is also large. Les. Also, discoloration is observed in visual evaluation. In this regard, it was found that rutile titanium oxide is superior as a component of a solder resist composition having a high reflectance than anatase titanium oxide!

[0052] (2) Heat resistance

Each test piece prepared in the same manner as (1) was measured with a Minolta color difference meter CR-400. Next, it was accelerated and deteriorated by heating at 150 ° C for 500 hours and 1000 hours in a hot-air circulating drying oven. The results are shown in Table 3.

[Table 3] Table 3

[0053] As is apparent from Table 3, in Examples 1 to 3 using the composition of the present invention, the reflectance did not decrease even after accelerated deterioration, and the change in brightness was small and the change in color. It can be seen that the value of AE * ab is small. Also, there is no or almost no discoloration by visual evaluation.

Comparative Examples;! To 3 are those using an epoxy compound other than the hydrogenated epoxy compound.

As can be seen from Table 3, both the reflectance Y and lightness L * of the composition containing epoxy compounds other than hydrogenated epoxy compounds in the solder resist composition are greatly reduced after accelerated thermal degradation. The value of AE * ab, which is a color change, is also large. Also, discoloration is observed in visual evaluation. From this, it can be seen that when an epoxy compound other than a hydrogenated epoxy compound is used in the resin in the solder resist composition, the solder resist film is deteriorated by heat.

[0055] (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, then a peel test was performed with a cellophane adhesive tape, and peeling and discoloration of the coating film were observed. evaluated. The results are also shown in Table 4. Here, a circle indicates that there was no peeling or discoloration of the coating film, and a cross indicates that there was peeling or discoloration of the coating film.

[0056] (4) Pencil hardness test

Pencils from B to 9H, which are sharpened so that the tip of the core is flattened, are pressed at an angle of about 45 ° to each test piece prepared in the same way as in (1), and the paint film does not peel off. The hardness of was recorded. The results are also shown in Table 4.

[0057] (5) Insulation resistance test

Specimens were prepared under the same conditions as in (1), except that the IPC B-25 test pattern comb-type electrode B coupon was used instead of the FR-4 copper-clad laminate. A bias of DC500V was applied to this test piece, and the insulation resistance value was measured. The results are also shown in Table 4.

[Table 4] Table 4

[0058] As is apparent from Table 4, in the examples using the solder resist composition of the present invention:! To 3, good heat resistance, solvent resistance, adhesion and electrical properties required for the solder resist film were obtained. It was found to have insulating properties.

[0059] As described in detail above, according to the present invention, a photocurable and thermosetting white solder resist composition capable of forming a solder resist film having a high reflectance can be obtained. The solder resist film having a high reflectivity formed by the solder resist composition of the present invention can withstand long-term use in response to light degradation and thermal degradation.

Claims

The scope of the claims

[1] Including (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 photo-curing / thermo-curing solder resist composition.

[2] 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. The white light-curing / thermosetting solder resist composition described.

[3] A resin having no aromatic ring, a carboxyl group-containing resin (A) 1 (a) a carboxyl group-containing (meth) acrylic copolymer resin produced from an aliphatic polymerizable monomer having 2 to 20 carbon atoms; (B) a copolymer resin having a carboxyl group obtained by a reaction of an oxysilane 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 according to claim 1.

[4] The hydrogenated epoxy compound (C) is a hydrogenated bisphenol A type epoxy resin obtained by selective nuclear hydrogenation of an aromatic ring of an aromatic epoxy compound. ~ 3! /, A white photocurable .thermosetting solder resist composition according to any one of the above items.

[5] In the photocurable / thermosetting solder resist composition according to any one of claims 1 to 4, the blending amount of the photopolymerization initiator (B) has the aromatic ring. Carboxyl group-containing resin (A) with respect to 100 parts by mass;! To 30 parts by mass, and the amount of the hydrogenated epoxy compound (C) does not have the aromatic ring! /, Carboxy 5 to 70 parts by mass with respect to 100 parts by mass of the group-containing resin (A), the compounding power S of the rutile titanium oxide (D), and the carboxy group-containing resin (A) 100 parts by mass not having the aromatic ring The blending amount of the diluent (E) is 50 to 300 parts by weight with respect to parts, and the carboxyl group-containing resin (A) having no aromatic ring is 20 to 300 parts by weight with respect to 100 parts by weight. A white photo-curing / thermo-curing solder resist composition characterized by being part by mass.

[6] The white photocurable / thermosetting solder resist composition according to any one of claims 1 to 5, further comprising (F) silica particles.

[7] The amount of the silica particles (F) does not have the aromatic ring! /, A carboxy group-containing resin (A

7. The white photocurable / thermosetting solder resist composition according to claim 6, wherein the composition is 50 to 200 parts by mass with respect to 100 parts by mass.

[8] Obtained by forming a solder resist film on the surface of the printed wiring board on which the circuit has been formed, using the white photocurable and thermosetting solder resist composition according to any one of claims 1 to 7. Printed wiring board.