KR101040781B1 - Solder resist composition and printed wiring board formed using the same - Google Patents

Abstract

The present invention provides a printed wiring board having a high reflectivity and high resolution solder resist composition, and a solder resist formed using the composition.

The soldering resist composition of this invention is resin containing an ethylenically unsaturated group and a carboxyl group in 1 molecule, a bisacylphosphine oxide type photoinitiator, a monoacylphosphine oxide type photoinitiator, a photopolymerizable monomer, and oxidation Titanium, an epoxy compound, and the organic solvent are contained, It is characterized by the above-mentioned.

Printed wiring board, soldering resist composition, ethylenically unsaturated group, carboxyl group, bisacylphosphine oxide type photoinitiator, monoacylphosphine oxide type photoinitiator, photopolymerizable monomer, titanium oxide, epoxy compound, organic solvent

Description

Solder resist composition and printed wiring board formed using this {SOLDER RESIST COMPOSITION AND PRINTED WIRING BOARD FORMED USING THE SAME}

The present invention relates to a printed wiring board having a solder resist composition suitable for use as a permanent mask of a printed wiring board and capable of forming a high reflectivity solder resist, and a solder resist formed using the solder resist composition.

A printed wiring board is used for electronic devices, etc., and consists of a board (board) in which an electronic component was mounted, and the circuit laid on it. There are various methods of forming this circuit, for example, there is a method of forming a circuit wiring by removing an unnecessary portion of a copper foil bonded to a laminate by etching. And electrical connection is performed by mounting an electronic component by soldering on a printed wiring board. In addition, in this specification, a printed wiring board refers to both the thing which formed the circuit and the thing which mounted the electronic component in the formed circuit. And a soldering resist is used as a protective film which protects a circuit at the time of soldering this electronic component. This soldering resist is formed by apply | coating a soldering resist composition to a base material, and hardening.

In addition, the solder resist prevents the deterioration of the conductor by oxygen or moisture in order to prevent the solder from being attached to the printed circuit board in addition to the place where the solder is to be soldered and to prevent the conductor from being exposed to air. In addition, a soldering resist functions also as a permanent protective film of a printed wiring board. Therefore, the solder resist requires properties such as adhesion, electrical insulation, solder heat resistance, solvent resistance, and chemical resistance.

Further, in order to realize a higher density of wirings, printed wiring boards are progressing in miniaturization (fineness), multilayering, and original boards, and their mounting methods are also being changed by surface mounting technology (SMT). For this reason, demands on the pinning, high resolution, high precision, and high reliability also increase for solder resists.

Also, in recent years, applications for directly mounting a light emitting diode (LED), which emits light at low power, such as a backlight of a liquid crystal display such as a portable terminal, a personal computer, a television, and a light fixture, and a solder resist are increasingly used. have. Therefore, in order to utilize light, such as LED efficiently, the printed wiring board which has a high reflectivity soldering resist is calculated | required.

As this high reflectivity soldering resist, what contains white pigments, such as a titanium oxide, is mentioned.

Here, there are a variety of methods for forming a pattern of solder resist (hereinafter referred to as a "pattern"), and among them, a photolithography method capable of accurately forming a fine pattern is often used. In particular, the alkali development type photolithography method has become a mainstream of environmental considerations.

Patent Literature 1 and Patent Literature 2 disclose solder resist compositions that can be developed in an aqueous alkali solution using a reaction product obtained by reacting an unsaturated monocarboxylic acid with a novolak-type epoxy resin and further adding polybasic anhydride.

In this photolithography method, the resin composition is irradiated with UV light or the like to perform patterning. However, when forming the high reflectivity solder resist, since the titanium oxide or the like contained in the solder resist composition used for the formation absorbs or reflects the light at the time of exposure, the solder resist composition sufficiently absorbs the light necessary for curing. There was a problem that it could not be absorbed and the resolution thereof was lowered. Therefore, formation of the high precision pattern by the photolithographic method was difficult about such a soldering resist composition.

<Patent Document 1> Japanese Patent Application Laid-Open No. 1-54390

<Patent Document 2> Japanese Patent Application Laid-Open No. 7-17737

An object of the present invention is to provide a soldering resist composition which is excellent in resolution and capable of forming a soldering resist having a high reflectance even when a large amount of titanium oxide is contained.

Another object of the present invention is to provide a printed wiring board having a high reflectivity and a high precision solder resist.

In this invention, a bisacyl phosphine oxide type photoinitiator and a monoacyl phosphine oxide type photoinitiator are used together as a photoinitiator. As a result, even in a high-reflective soldering resist composition containing a large amount of titanium oxide, it is possible to form an excellent pattern with excellent resolution.

That is, the soldering resist composition of this invention (1) resin which contains an ethylenically unsaturated group and a carboxyl group in 1 molecule, a bisacyl phosphine oxide type photoinitiator, a monoacylphosphine oxide type photoinitiator, and photopolymerization It is characterized by containing a monomer, titanium oxide, an epoxy compound, and an organic solvent.

(2) Furthermore, the soldering resist composition of this invention contains a thioxanthone type photoinitiator in addition to (1).

(3) In addition, the soldering resist composition of this invention is characterized by including antioxidant in addition to (1).

(4) Specifically, titanium oxide is characterized by rutile titanium oxide.

(5) More specifically, a resin containing an ethylenically unsaturated group and a carboxyl group in one molecule has a carboxyl group obtained by reaction of a carboxyl group-containing (meth) acrylic copolymer resin with a compound having an oxirane ring and an ethylenically unsaturated group in one molecule. It is preferable that it is a copolymer resin, and the compound which has an oxirane ring and ethylenically unsaturated group in 1 molecule is a compound produced from an aliphatic polymerizable monomer.

(6) The present invention is also characterized in that it is a printed wiring board having a solder resist formed using these solder resist compositions.

(7) The present invention also includes a reactant of an ethylenically unsaturated group, a bisacylphosphine oxide photopolymerization initiator, a monoacylphosphine oxide photopolymerization initiator, titanium oxide, a reactant of an epoxy compound and a carboxyl group. It is characterized in that the solder resist formed on the printed wiring board.

According to the present invention, it is possible to provide a solder resist composition which contains a large amount of titanium oxide and has a high reflectance, which is excellent in resolution and can form a high-precision pattern.

Moreover, according to this invention, it becomes possible to provide the printed wiring board which has a high precision and the soldering resist which can suppress deterioration of resin and can maintain high reflectance for a long time.

Hereinafter, the present invention will be described in detail.

The soldering resist composition of this invention is resin containing an ethylenically unsaturated group and a carboxyl group in 1 molecule, a bisacylphosphine oxide type photoinitiator, a monoacylphosphine oxide type photoinitiator, a photopolymerizable monomer, and oxidation Titanium, an epoxy compound, and an organic solvent are included.

In addition, below, this coating film means the coating film formed using the soldering resist composition of this invention.

[Resin containing ethylenically unsaturated group and carboxyl group in 1 molecule]

The resin containing an ethylenically unsaturated group and a carboxyl group in one molecule (hereinafter referred to as "photocurable resin") may be a resin having a carboxyl group which enables development by an ethylenically unsaturated group and a weak alkali aqueous solution for photocurability in one molecule. It may be, but is not limited to a specific one. Such photocurable resin can use preferably resin (it may be any of an oligomer or a polymer) listed to the following (1)-(3). In other words,

(1) Photosensitive carboxyl group-containing resin obtained by reaction of carboxyl group-containing (meth) acrylic-type copolymer resin and the compound which has an oxirane ring and an ethylenically unsaturated group in 1 molecule.

(2) Unsaturated monocarboxylic acid is reacted with the copolymer of the compound which has one epoxy group and one unsaturated double bond, and the compound which has unsaturated double bond in 1 molecule, and is the secondary grade produced by this reaction. Photosensitive carboxyl group-containing resin obtained by making saturated or unsaturated polybasic acid anhydride react with a hydroxyl group.

(3) A photosensitive compound obtained by reacting a saturated or unsaturated polybasic acid anhydride with a hydroxyl group-containing polymer and then reacting a carboxylic acid produced by this reaction with a compound having one epoxy group and one unsaturated double bond in one molecule. Hydroxyl group and carboxyl group-containing resin.

Among these, in the photosensitive carboxyl group-containing resin of (1), the copolymer type resin which has a carboxyl group obtained by reaction with a carboxyl group-containing (meth) acrylic-type copolymer resin and the compound which has an oxirane ring and an ethylenically unsaturated group in 1 molecule is photocurable It is preferably used as the resin.

The carboxyl group-containing (meth) acrylic copolymer resin is obtained by copolymerizing (meth) acrylic acid ester with a compound having one unsaturated group and one or more carboxyl groups in one molecule. As (meth) acrylic acid ester, such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, Meth) acrylic acid alkyl esters, 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, caprolactone-modified 2-hydroxyethyl (meth) acrylate, etc. Hydroxyl group-containing (meth) acrylic acid esters, methoxydiethylene glycol (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, isooctyloxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylic Glycol modified (meth) acrylates, such as a rate and a methoxy polyethyleneglycol (meth) acrylate, etc. are mentioned. These may be used alone, or may be used by mixing a plurality. In addition, in this specification, a (meth) acrylate is a term which generically refers to an acrylate and a methacrylate, and is the same also about the expression of another similarity.

Moreover, as a compound which has one unsaturated group and one or more carboxyl groups in 1 molecule, the modified unsaturated monocarboxylic acid ((beta) -carboxyethyl (meth) acrylate which chain extended between acrylic acid, methacrylic acid, an unsaturated group, and a carboxylic acid is extended). , 2-acryloyloxyethyl succinic acid, 2-acryloyloxyethyl hexahydrophthalic acid, unsaturated monocarboxylic acid having ester linkage by lactone modification, etc., modified unsaturated monocarboxylic acid having ether linkage), maleic acid, etc. The thing containing two or more carboxyl groups in a molecule | numerator, etc. are mentioned. These may be used alone, or may be used by mixing a plurality.

It is preferable to use the compound produced from an aliphatic monomer as a compound which has an oxirane ring and ethylenically unsaturated group in 1 molecule. In particular, when the compound produced | generated from an aliphatic polymerizable monomer is used, since deterioration of the hardened | cured material by the light resulting from the aromatic ring of photocurable resin is suppressed, it is preferable. Examples of the compound produced from aliphatic monomers include glycidyl (meth) acrylate, α-methylglycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, and 3,4-epoxycyclohexylethyl. (Meth) acrylate, 3, 4- epoxycyclohexyl butyl (meth) acrylate, 3, 4- epoxycyclohexyl methylamino acrylate, 3, 4- epoxycyclohexyl methyl (meth) acrylate, etc. are mentioned. . The compound which has an oxirane ring and ethylenically unsaturated group in 1 molecule may be used individually, or may be used in mixture of multiple.

The photocurable resin needs to have its acid value in the range of 50-200 mgKOH / g. When the acid value of photocurable resin is less than 50 mgKOH / g, removal of the unexposed part of this coating film in weak alkali aqueous solution is difficult. In addition, when the acid value of the photocurable resin exceeds 200 mgKOH / g, problems such as poor water resistance and electrical characteristics of the solder resist occur. Moreover, it is preferable that the weight average molecular weight of photocurable resin exists in the range of 5,000-100,000. When the weight average molecular weight of photocurable resin is less than 5,000, there exists a tendency for the touch drying property of this coating film to fall remarkably. Moreover, when the weight average molecular weight of photocurable resin exceeds 100,000, since the developability of this coating film and the storage stability of a soldering resist composition deteriorate remarkably, it is unpreferable.

[Bisacylphosphine oxide type photoinitiator]

As a bisacyl phosphine oxide type photoinitiator (henceforth "BAPO"), bis- (2, 6- dichloro benzoyl) phenyl phosphine oxide, bis- (2, 6- dichloro benzoyl)-2, 5- dimethyl Phenylphosphine oxide, bis- (2,6-dichlorobenzoyl) -4-propylphenylphosphine oxide, bis- (2,6-dichlorobenzoyl) -1-naphthylphosphine oxide, bis- (2,6- Dimethoxybenzoyl) phenylphosphine oxide, bis- (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphineoxide, bis- (2,6-dimethoxybenzoyl) -2,5-dimethyl Phenyl phosphine oxide, bis- (2,4,6-trimethylbenzoyl) phenylphosphine oxide, (2,5,6-trimethylbenzoyl) -2,4,4-trimethylpentylphosphine oxide, and the like. Among them, bis- (2,4,6-trimethylbenzoyl) phenylphosphine oxide (Shiba Japan Co., Ltd. make, brand name; Irgacure 819) is easy to obtain.

[Monoacyl phosphine oxide type photoinitiator]

As a monoacyl phosphine oxide type photoinitiator (henceforth "MAPO"), 2,4,6- trimethyl benzoyl diphenyl phosphine oxide, 2, 6- dimethoxy benzoyl diphenyl phosphine oxide, 2, 6- Dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphinic acid methyl ester, 2-methylbenzoyldiphenylphosphine oxide, pivaloylphenylphosphinic acid isopropyl ester and the like. Especially, 2,4,6- trimethyl benzoyl diphenyl phosphine oxide (Shiba Japan Co., Ltd. make, brand name; Tarocure TPO) is easy to obtain.

In the present invention, even when a coating film of a high reflectivity solder resist composition containing titanium oxide is cured by using BAPO and MAPO together, it can be cured by a small amount of light passing through the coating film. While it is possible to form a precise pattern. Moreover, the photosensitive fine adjustment of the soldering resist composition of this invention can be performed by changing the compounding ratio of BAPO and MAPO further. That is, in the cross-sectional shape of the pattern formed in the base material, when the undercut is easy to come out due to the lack of core hardening property on the base surface side of the pattern, the blending ratio of BAPO is increased. Moreover, when the surface state of the pattern after image development is bad because of lack of surface hardening property of this coating film, the compounding ratio of MAPO is made large. The blending ratio of BAPO and MAPO is 90:10 to 1:99, preferably 80:20 to 2:98. Outside the range of this mixing | blending ratio, the effect by combined use of BAPO and MAPO decreases, and since the optical sensitivity required for hardening of this coating film cannot be obtained, high-precision pattern formation cannot be performed. Moreover, the total compounding quantity of BAPO and MAPO becomes like this. Preferably it is 1-30 mass parts, More preferably, it is 2-25 mass parts with respect to 100 mass parts of photocurable resins. When the total compounding quantity of BAPO and MAPO is less than 1 mass part with respect to 100 mass parts of photocurable resins, since the photocurability of this coating film falls and the pattern formation after exposure and image development becomes difficult, it is unpreferable. Moreover, when the total compounding quantity of BAPO and MAPO exceeds 30 mass parts with respect to 100 mass parts of photocurable resins, since coloring of the coating film derived from a photoinitiator becomes large and it becomes a cause of unit price increase, it is unpreferable.

[Photopolymerizable Monomer]

As a photopolymerizable monomer, Hydroxyalkyl acrylates, such as 2-hydroxyethyl acrylate and 2-hydroxybutyl acrylate; Mono or diacrylates of glycols such as ethylene glycol, methoxy tetraethylene glycol, polyethylene glycol and propylene glycol; Acrylamides such as N, N-dimethylacrylamide and N-methylolacrylamide; Aminoalkyl acrylates such as N, N-dimethylaminoethyl acrylate; Polyhydric alcohols such as hexanediol, trimethylolpropane, pentaerythritol, dipentaerythritol, tris-hydroxyethyl isocyanurate or polyhydric acrylates of these ethylene oxide or propylene oxide adducts; Acrylates such as phenoxyacrylate, bisphenol A diacrylate, and ethylene oxide or propylene oxide adducts of these phenols; Acrylates of glycidyl ethers such as glycerin diglycidyl ether and trimethylolpropane triglycidyl ether; Melamine acrylate; And / or methacrylates corresponding to the acrylates.

The compounding quantity of a photopolymerizable monomer becomes like this. Preferably it is 10-100 mass parts, More preferably, it is 20-80 mass parts with respect to 100 mass parts of photocurable resins. When the compounding quantity of a photopolymerizable monomer exceeds 100 mass parts with respect to 100 mass parts of photocurable resins, since the physical property of the formed soldering resist falls, it is unpreferable. Moreover, since this coating film does not have sufficient photocurability, when the compounding quantity of a photopolymerizable monomer is less than 10 mass parts with respect to 100 mass parts of photocurable resins, a high precision pattern is not obtained.

[Titanium oxide]

Titanium oxide may be either anatase titanium oxide or rutile titanium oxide, but rutile titanium oxide is particularly preferable. Since the anatase titanium oxide has a higher reflectance near the boundary between the ultraviolet region and the visible region than the rutile titanium oxide, it is preferable as a white pigment in terms of whiteness and reflectance. However, since the anatase titanium oxide has a photocatalytic activity, this photoactivity may cause discoloration of the resin of the solder resist composition. On the other hand, the rutile titanium oxide is slightly inferior to the anatase titanium oxide, but has little photoactivity, so that deterioration of the resin of the solder resist composition can be suppressed, and a stable solder resist can be obtained.

Specific examples of the rutile titanium oxide include Typek R-820, Taipek R-830, Taipek R-930, Taipek R-550, Taipek R-630, Taipek R-680, Taipek R-670, Taipek R-680, Taipek R-670, Taipek R-780, Taipek R-850, Taipek CR-50, Taipek CR-57, Taipek CR-80, Taipek CR-90, Taipek CR-93, Taipe CR-95, Taipe CR-97, Taipe CR-60, Taipe CR-63, Taipe CR-67, Taipe CR-58, Taipe CR-85, Taipe UT771 ( Ishihara Sangyo Co., Ltd.), Tai Pure R-100, Tai Pure R-101, Tai Pure R-102, Tai Pure R-103, Tai Pure R-104, Tai Pure R-105, Tai Pure R-108, Tie Pure R-900, Tie Pure R-902, Tie Pure R-960, Tie Pure R-706, Tie Pure R-931 (manufactured by DuPont), T-Tone R-25, T-Tone R-21, Teton R-32, Teton R-7E, Teton R-5N, Teton R-61N, Teton R-62N, Teton R-42, Teton R-45M, Teton R-44, Teton R-49S, Teton GTR-100,Tone GTR-300, Teton D-918, Teton-TCR 29, TCR-Teton 52, Teton FTR-700 and the like (the Sakai Kagaku Kogyo Co., Ltd.).

As the anatase titanium oxide, TA-100, TA-200, TA-300, TA-400, TA-500 (manufactured by Fuji Titanium Co., Ltd.), Typek A-100, Typek A-220, Thai Pec W-10 (manufactured by Ishihara Sangyo Co., Ltd.), Titanics (TITANIX) JA-1, Titanics JA-3, Titanics JA-4, Titanics JA-5 (Teika Co., Ltd.), Chronos ( KRONOS) KA-10, Chronos KA-15, Chronos KA-20, Chronos KA-30 (manufactured by Titanium High School), A-100, A-100, A-100, SA-1, SA-1L (Sakai Kagaku Kogyo Co., Ltd.) etc. are mentioned.

The compounding quantity of titanium oxide becomes like this. Preferably it is 50-450 mass parts, More preferably, it is 60-350 mass parts with respect to 100 mass parts of photocurable resins. When the compounding quantity of titanium oxide exceeds 450 mass parts with respect to 100 mass parts of photocurable resins, since the photocurability of the soldering resist composition of this invention falls and hardening depth will become low, it is unpreferable. On the other hand, when the compounding quantity of titanium oxide is less than 50 mass parts with respect to 100 mass parts of photocurable resins, the hiding power of the said soldering resist composition becomes small and a high reflectivity soldering resist cannot be obtained.

Epoxy Compound

Examples of the epoxy compound include three bisphenol S-type epoxy resins, diglycidyl phthalate resins, and triglycidyl isocyanurate (Tepic (TEPIC) -H (S-triazine ring skeleton surface manufactured by Nissan Chemical Industries, Ltd.). Β-body having a structure in which an epoxy group is bonded in the same direction) or tepic (a mixture of β-body and α-body having a structure in which one epoxy group is bonded in a different direction to two epoxy groups having different epoxy groups with respect to the S-triazine ring skeleton) Epoxy resins that are poorly soluble in diluents such as heterocyclic epoxy resins, bixylenol type epoxy resins, biphenyl type epoxy resins, tetraglycidyl xylenoylethane resins, and the like, bisphenol A type epoxy resins and hydrogenated bisphenol A types Epoxy resin, bisphenol F resin, brominated bisphenol A epoxy resin, phenol novolac or cresol novolac epoxy resin, alicyclic epoxy resin, bisphenol A Diluents such as volac type epoxy resin, chelate type epoxy resin, glyoxal type epoxy resin, amino group-containing epoxy resin, rubber modified epoxy resin, dicyclopentadienephenolic epoxy resin, silicone modified epoxy resin, ε-caprolactone modified epoxy resin Epoxy resin which is soluble in, etc. are mentioned. These epoxy resins can be used individually or in combination of many.

The compounding quantity of an epoxy compound becomes like this. Preferably it is 5-70 mass parts, More preferably, it is 5-60 mass parts with respect to 100 mass parts of photocurable resins. When the compounding quantity of an epoxy compound exceeds 70 mass parts with respect to 100 mass parts of photocurable resins, the solubility of the unexposed part in a developing solution will fall with respect to this coating film, and developing residue will become easy to generate, and it becomes difficult to form a pattern. . On the other hand, when the compounding quantity of an epoxy compound is less than 5 mass parts with respect to 100 mass parts of photocurable resins, since the carboxyl group of photocurable resin remains in a solder resist in the unreacted state, the electrical characteristics, solder heat resistance, and chemical resistance of a soldering resist are This becomes difficult to obtain sufficiently.

Moreover, it reacts by ring-opening polymerization with the carboxyl group of photocurable resin and the epoxy group of an epoxy compound. In this case, when the water-soluble epoxy resin is mix | blended with the said composition with respect to the other substance of an organic solvent or a soldering resist composition, the crosslinking of the said carboxyl group and an epoxy group advances by the heat of drying at the time of forming a coating film. It becomes easy to be. Therefore, when it is desired to take a long time to suppress the crosslinking reaction and to dry, it is preferable to mix the poorly water-soluble epoxy resin alone or in combination with the water-soluble epoxy resin with respect to the organic solvent and other substances of the composition.

An organic solvent is used in order to make the soldering resist composition of this invention easy to apply | coat to a base material etc., and to apply | coat and dry the said composition containing an organic solvent to a base material etc., and to form a coating film. As an organic solvent, 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, dipropylene glycol monoethyl ether, triethylene glycol monoethyl ether Glycol ethers such as these; Esters such as ethyl acetate, butyl acetate, cellosolve acetate, diethylene glycol monoethyl ether acetate, and esterified products of the glycol ethers; Alcohols such as ethanol, propanol, ethylene glycol and propylene glycol; Aliphatic hydrocarbons such as octane and decane; Petroleum solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, solvent naphtha and the like.

The organic solvent can be used alone or as a plurality of mixtures. As for the compounding quantity of an organic solvent, 20-300 mass parts is preferable with respect to 100 mass parts of photocurable resins.

A thioxanthone type photopolymerization sensitizer can be mix | blended with the soldering resist composition of this invention for the purpose of improving the sensitivity with respect to the light at the time of exposure.

When a thioxanthone type photopolymerization sensitizer is mix | blended with the composition which used BAPO and MAPO together, the effect of the improvement of the light sensitivity of the said composition can be heightened more. As thioxanthone type photopolymerization sensitizer, thioxanthone, 2-ethyl thioxanthone, 2-isopropyl thioxanthone, 2-chloro thioxanthone, 2, 4- dimethyl thioxanthone, 2, 4- diethyl Thioxanthone, 2, 4- diisopropyl thioxanthone, etc. are mentioned.

The compounding quantity of a thioxanthone type photoinitiator is preferably 0.05-2 mass parts with respect to 100 mass parts of photocurable resins, More preferably, it is 0.1-1 mass part. When the compounding quantity of a thioxanthone type photoinitiator is less than 0.05 mass part with respect to 100 mass parts of photocurable resins, the effect of the sensitivity improvement of the soldering resist composition of this invention is small. Moreover, when the compounding quantity of a thioxanthone type photopolymerization sensitizer exceeds 2 mass parts with respect to 100 mass parts of photocurable resins, coloring of the coating film derived from thioxanthone will become large.

Antioxidant can be mix | blended with the soldering resist composition of this invention in order to reduce discoloration by the thermal deterioration of a soldering resist. As the antioxidant, a hindered phenol compound is preferably used, but is not limited thereto. As a hindered phenol type compound, the no crack 200, the no crack M-17, the no crack SP, the no crack SP-N, the no crack NS-5, the no crack NS-6, the no crack NS-30, the no crack 300, the no crack NS-7, no crack DAH (all are manufactured by Ouchi Shinko Chemical 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 of which are manufactured by Adeka Gas 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 are manufactured by Shiva Japan Co., Ltd.).

The compounding quantity of antioxidant becomes like this. Preferably it is 0.4-25 mass parts, More preferably, it is 0.8-15 mass parts with respect to 100 mass parts of photocurable resins. When the compounding quantity of antioxidant is less than 0.4 mass part with respect to 100 mass parts of photocurable resins, the discoloration prevention effect by the thermal deterioration of a soldering resist is small. Moreover, when the compounding quantity of antioxidant exceeds 25 mass parts with respect to 100 mass parts of photocurable resins, developability of this coating film falls and a problem arises in patterning.

Moreover, a hindered amine light stabilizer can be mix | blended with the soldering resist composition of this invention for the purpose of reducing light deterioration.

Examples of the hindered amine light stabilizer include Tinuvin 622LD and Tinuvin 144; CHIMASSORB 944LD and CHIMASSORB 119FL (both manufactured by Shiba Japan Co., Ltd.); MARK LA-57, LA-62, LA-67, LA-63, LA-68 (all of which are manufactured by Adekagas Chemical Co., Ltd.); Sunol LS-770, LS-765, LS-292, LS-2626, LS-1114, LS-744 (all are manufactured by Sankyo Lifetech Co., Ltd.) and the like.

It is preferable that the compounding quantity of a hindered amine light stabilizer is 0.1-10 mass parts with respect to 100 mass parts of photocurable resins.

Moreover, a dispersing agent can be mix | blended with the soldering resist composition of this invention for the purpose of the improvement of the dispersibility and settling property of titanium oxide. As dispersants, anti-terra (ANTI-TERRA) -U, anti-terra-U100, anti-terra-204, anti-terra-205, DISPERBYK-101, dispervik-102, dispervik- 103, DISPERVIK-106, DISPERVIK-108, DISPERVIK-109, DISPERVIK-110, DISPERVIK-111, DISPERVIK-112, DISPERVIK-116, DISPERVIK-130, Dispervik-140, dispervik-142, dispervik-145, dispervik-161, dispervik-162, dispervik-163, dispervik-164, dispervik-166, disper Vik-167, Dispervik-168, Dispervik-170, Dispervik-171, Dispervik-174, Dispervik-180, Dispervik-182, Dispervik-183, Dispervik- 185, DISPERVIK-184, DISPERVIK-2000, DISPERVIK-2001, DISPERVIK-2009, DISPERVIK-2020, DISPERVIK-2025, DISPERVIK-2050, DISPERVIK-2070, DISPERVIK-2096, DISPERVIK-2150, BYK-P104, BYK-P104S, BYK-P105, BYK-9076, BYK-9077, BYK-220S Pan Co., Ltd.), Dispalon 2150, Dispalon 1210, Dispalon KS-860, Dispalon KS-873N, Dispalon 7004, Dispalon 1830, Dispalon 1860, Dispalon 1850, Dispalon DA-400N, Dispalon Fallon PW-36, Dispalon DA-703-50 (manufactured by Kusumoto Kasei Co., Ltd.), Floren G-450, Floren G-600, Floren G-820, Floren G-700, Floren DOPA -44 and Floren DOPA-17 (made by Kyoesha Chemical Co., Ltd.) are mentioned.

In order to achieve the said objective effectively, the compounding quantity of a dispersing agent shall be 0.1-10 mass parts with respect to 100 mass parts of titanium oxide, Preferably it is 0.5-5 mass parts.

Moreover, a hardening accelerator, a thermal polymerization inhibitor, a thickener, an antifoamer, a leveling agent, a coupling agent, a flame retardant adjuvant, etc. can be mix | blended with the soldering resist composition of this invention.

Hereinafter, as a use example of the soldering resist composition of this invention, the printed wiring board manufactured using the said composition is demonstrated.

First, the soldering resist composition of this invention is adjusted to the viscosity suitable for a coating method.

Next, the viscosity-adjusted composition is applied to a printed circuit board having a circuit formed by a method such as a screen printing method, a curtain coating method, a spray coating method, or a roll coating method. Then, the organic solvent contained in the composition apply | coated to the printed wiring board is volatilized at the temperature of 70-90 degreeC, and a coating film is formed.

Thereafter, the coating film is selectively exposed to light by an active energy ray through a photomask. And the unexposed part of the said coating film after exposure is developed using aqueous alkali solution, and a pattern is formed. Moreover, after that, the pattern is heat-cured by heat at 100 ° C to 200 ° C, whereby a printed wiring board having a pattern formed using the solder resist composition of the present invention, that is, the printed wiring board of the present invention can be produced.

As the irradiation light source for exposing the coating film, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultra high pressure mercury lamp, a xenon lamp or a metal halide lamp can be used. In addition, a laser beam etc. can also be used as an active ray.

In addition, although the aqueous alkali solution as a developing solution used for image development of the said coating film is 0.5-5 mass% sodium carbonate aqueous solution, other alkaline aqueous solution can also be used. As another alkali aqueous solution, aqueous alkali solution, such as potassium hydroxide, sodium hydroxide, potassium carbonate, sodium phosphate, sodium silicate, ammonia, amines, is mentioned.

<Examples>

Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not limited to this.

Synthesis of Resin Solution 1:

900 g of solvent (diethylene glycol dimethyl ether) and a polymerization initiator (t-butylperoxy 2-ethylhexanoate, Nisbon Yushi) in a 2-liter separation flask equipped with a stirrer, a thermometer, a reflux cooler, a dropping funnel and a nitrogen introduction tube. (Manufactured by Co., Ltd.), 21.4 g of perbutyl O) were added, and it heated at 90 degreeC. After heating, 309.8 g of methacrylic acid, 116.4 g of methyl methacrylate, 109.8 g of lactone-modified 2-hydroxyethyl methacrylate (manufactured by Daicel Chemical Industries, Ltd., trade name; Praccell FM1) were added to the flask after heating. 21.4 g of polymerization initiators (bis (4-t-butylcyclohexyl) peroxydicarbonate, manufactured by Nippon Yushi Co., Ltd., brand name; perroyl TCP) were added dropwise over 3 hours. Moreover, the carboxyl group-containing copolymer resin was obtained by aged the said mixture for 6 hours. In addition, these reactions were performed in nitrogen atmosphere.

Next, 363.9 g of 3,4-epoxycyclohexyl methyl acrylate (made by Daicel Chemical Corporation, brand name; Cycroma A200), 3.6 g of a ring-opening catalyst (dimethylbenzylamine), and a polymerization inhibitor are then used for this carboxyl group-containing copolymer resin. 1.80 g of (hydroquinone monomethyl ether) were added, and the ring-opening addition reaction of epoxy was performed by heating and stirring these at 100 degreeC. After 16 hours from the end of stirring, the solution containing 53.8 mass% (non-volatile content) of the carboxyl group-containing resin which does not have the aromatic ring whose acid value of solid content is 108.9 mgKOH / g and a weight average molecular weight is 25,000 was obtained. Hereinafter, this reaction solution is called resin solution 1.

Formulations of Examples 1-5 and Comparative Examples 1-3:

What mix | blended each component according to description of Table 1 was stirred, and also this was disperse | distributed with the triaxial roll, and the soldering resist composition (Examples 1-5, Comparative Examples 1-3) was manufactured. In addition, the number in Table 1 represents a mass part.

Photoinitiator 1: bis- (2,4,6-trimethylbenzoyl) phenylphosphine oxide Irgacure 819 (made by Shiba Japan Co., Ltd.)

Photoinitiator 2: 2,4,6-trimethylbenzoyldiphenylphosphine oxide Darocure TPO (made by Shiba Japan Co., Ltd.)

Photoinitiator 3: Irgacure 907 (made by Shiba Japan Co., Ltd.)

Photopolymerizable monomer: dipentaerythritol hexaacrylate

Titanium oxide (rutile type): CR-Super 70 (manufactured by Ishihara Sangyo Co., Ltd.)

Epoxy compound (biphenyl type): YX-4000 (manufactured by Japan Epoxy Resin Co., Ltd.)

Sensitizer: 2,4-diethyl thioxanthone kayakure DETX-S (manufactured by Nippon Kayaku Co., Ltd.)

Antioxidant: Irganox 1010 (made by Shiba Japan Co., Ltd.)

Organic Solvent: Carbitol Acetate

Defoamer: Silicone oil KS-66 (manufactured by Shin-Etsu Chemical Co., Ltd.)

In order to investigate all the properties of the soldering resist formed using each soldering resist composition, it tested on the following conditions and evaluated.

(1) resolution

Each soldering resist composition used the board of 100 mesh polyester (Bias) so that the film thickness of the coating film might be 40 micrometers, The laminated board which coated FR-4 copper by the screen printing method (size: 100mm * 150mm, Thickness: 1.6 mm) in beta (full substrate). The FR-4 copper-clad laminate was dried in a hot air circulation drying furnace (temperature: 80 ° C., time: 10 minutes) to form a coating film of each solder resist composition. Moreover, each soldering resist composition was repeatedly printed on each said coating film by the same method as the above, and it dried in the hot air circulation type drying furnace (temperature: 80 degreeC, time: 20 minutes), and formed the test coating film. Subsequently, 500 mJ / cm &lt; 2 &gt; and 700 mJ / cm &lt; 2 &gt; The said test coating film was ultraviolet-ray-exposed with the accumulated light quantity of 2 conditions. Then, 1 mass% of sodium carbonate aqueous solution (temperature: 30 degreeC) was developed for 60 second using the developer for printed wiring boards as a developing solution with respect to this exposed test coating film. Subsequently, each test piece was manufactured by thermosetting (temperature: 150 degreeC, time: 60 minutes) with respect to each test coating film which developed. The line width which remained in these test pieces was confirmed, and the resolution was evaluated using the following evaluation methods. The results are shown in Table 2.

◎ 80 μm lines remain under 500 mJ / cm 2 exposure conditions

○ 80 µm remaining lines under exposure conditions of 700 mJ / cm 2

100 µm lines remain under exposure conditions of Δ700 mJ / cm 2, but a decrease in film is observed during development

X 100 µm lines do not remain under any of the above conditions

As shown in Table 2, since all the lines remain in Examples 1-5, it turned out that resolution is good. Although the bisacyl phosphine oxide type photoinitiator was used for the comparative example 1, the monoacyl phosphine oxide type photoinitiator was used for the comparative example 2, and the urethane type photoinitiator was used for the comparative example 3, It left no result.

(2) light resistance heat discoloration

In the soldering resist composition of Examples 1-5, the laminated board which coated FR-4 copper by the screen printing method using the board of 100 mesh polyester (Bias) so that the film thickness of the coating film might be 40 micrometers (size: 100) mm × 150 mm, thickness: 1.6 mm) and printed the pattern in beta (substrate whole surface). The FR-4 copper-clad laminate was dried in a hot air circulation drying furnace (temperature: 80 ° C., time: 30 minutes) to form a coating film of each solder resist composition. Furthermore, each coating film was exposed to ultraviolet rays using an integrated light quantity of 700 mJ / cm 2 so as to leave a negative pattern of 30 mm side using an exposure machine HMW-680GW (manufactured by Oak Seisakusho Co., Ltd.) for a printed wiring board. It was. Then, about each exposed coating film, 1 mass% sodium carbonate aqueous solution (temperature: 30 degreeC) was developed for 60 second using the developing machine for printed wiring boards as a developing solution. Then, about each developed coating film, it thermosetted (hot: 150 degreeC, time: 60 minutes) in the hot-air circulation type drying furnace, and produced each test piece for characteristic tests.

About each said test piece, each value of the Y value and L * a * b * colorimeter of the XYZ colorimeter was measured as the initial value using the chromatic colorimeter CR-400 (made by Konica Minolta Sensing Co., Ltd.). Then, using a conveyor-type UV irradiator QRM-2082-E-01 (manufactured by Oak Seisakusho Co., Ltd.), a metal halide lamp, cold mirror, 80 W / cm × 3 lights, conveyor speed 6.5 m / min ( Each test piece was repeatedly irradiated with UV 20 times on the conditions of accumulated light quantity 1000 mJ / cm <2>. Furthermore, after that, each said test piece was repeatedly heated twice using the conveyor heating furnace for component mounting. About each test piece after heating, the color difference was measured on the conditions similar to an initial value, and the deterioration state of each test piece was evaluated. In addition, each said test piece was evaluated also visually. The results are shown in Table 3. In addition, the temperature of the heating furnace is shown in FIG.

In Table 3, Y represents the reflectance of the XYZ color system, and L * represents the brightness of the L * a * b * color system. (DELTA) E * ab squares the difference of the value after a deterioration test, and an initial value with respect to each value of L * a * b *, and takes the square root of the sum total. a * represents a red direction, -a * represents a green direction, b * represents a yellow direction, -b * represents a blue direction, and it is indicated that there is no saturation closer to zero. ΔE * ab indicates a change in color, and the smaller this value, the smaller the change in color.

In addition, visual evaluation after a heating is as follows.

◎ No discoloration

○ almost no discoloration

△ There is a slight discoloration

× There is a clear discoloration

As shown in Table 3, Examples 1-5 have little discoloration also about the value of (DELTA) E * ab and visual evaluation after a heating.

(3) solder heat resistance

For Examples 1 to 5, a rosin-based flux was applied to each test piece produced in the same manner as in (2), and flowed for 10 seconds in a solder bath at 260 ° C. Then, each said test piece was wash | cleaned with propylene glycol monomethyl ether acetate, and it dried. Then, the peeling test by the cellophane adhesive tape was performed about each dried test piece, and the peeling of a cured coating film (henceforth a "coating film" in this Example) was evaluated using the following evaluation methods. The results are shown in Table 4.

○ No peeling or discoloration of the coating

× Peeling or discoloration of the coating

(4) solvent resistance

About Examples 1-5, each test piece manufactured by the method similar to (2) was immersed in propylene glycol monomethyl ether acetate for 30 minutes, and it dried. Then, the peeling test by the cellophane adhesive tape was performed about each dried test piece, and peeling and discoloration of a coating film were evaluated using the following evaluation methods. The results are shown in Table 4.

○ No peeling or discoloration of coating

× There was peeling or discoloration of the coating

(5) pencil hardness test

For Examples 1 to 5, the pencils of B-9H, which were ground so that the front of the core was flat on each test piece manufactured in the same manner as in (2), were pressed at an angle of about 45 ° so that no peeling of the coating film occurred. The hardness of was recorded and evaluated using the following evaluation methods. The results are shown in Table 4.

○ ... no peeling or discoloration of the coating film

× ··· There is peeling or discoloration of coating

(6) insulation resistance test

In Examples 1 to 5, comb-shaped Electrode B coupons of the IPC B-25 test pattern were used in place of the laminated plates coated with FR-4 copper, and test specimens were prepared under the same conditions and methods as in (2). DC500V bias was applied to each test piece, and insulation resistance value was measured. The results are shown in Table 4.

As is clear from the description of Table 4, it was found that Examples 1 to 5 using the solder resist composition of the present invention had good heat resistance, solvent resistance, adhesion, and electrical insulation required for the solder resist.

As mentioned above, according to the present Example, the soldering resist composition which can form the high reflectivity soldering resist was obtained. Moreover, even if the said composition is mix | blended with a large amount of titanium oxide, it turned out that a high-definition pattern can be formed by exposure and it has favorable resolution. Moreover, the soldering resist formed using the said composition had little discoloration by light and heat, and also had solder heat resistance.

1 is a graph showing a temporal change of a furnace temperature used in evaluation of light resistance to heat discoloration of an example.

Claims (8)

Resin containing an ethylenically unsaturated group and a carboxyl group in one molecule, Bisacyl phosphine oxide type photoinitiator, Monoacyl phosphine oxide type photoinitiator, Photopolymerizable monomer, Titanium oxide, An epoxy compound, A soldering resist composition comprising an organic solvent. The soldering resist composition according to claim 1, wherein the titanium oxide is rutile titanium oxide. The soldering resist composition of Claim 1 containing a thioxanthone type photopolymerization sensitizer. The soldering resist composition of claim 1 comprising an antioxidant. The air according to claim 1, wherein the resin containing an ethylenically unsaturated group and a carboxyl group in one molecule has a carboxyl group obtained by the reaction of a carboxyl group-containing (meth) acrylic copolymer resin with a compound having an oxirane ring and an ethylenically unsaturated group in one molecule. It is total resin, The soldering resist composition characterized by the above-mentioned. The soldering resist composition of Claim 5 whose compound which has an oxirane ring and ethylenically unsaturated group in 1 molecule is a compound produced from an aliphatic polymerizable monomer. The printed wiring board which has a soldering resist formed using the soldering resist composition of any one of Claims 1-6. Reactants of ethylenically unsaturated groups, Bisacyl phosphine oxide type photoinitiator, Monoacyl phosphine oxide type photoinitiator, Titanium oxide, A soldering resist formed on a printed wiring board, comprising a reactant of an epoxy compound and a carboxyl group.

Images