KR100904348B1 - Photocurable thermosetting resin composition and printed wiring board using same - Google Patents

Abstract

This invention is a composition which can form the high reflectivity soldering resist film used as a soldering resist, The white photocurable thermosetting resin composition which can form a pattern latent image correctly when irradiated with light, and this white photocurable Provided is a printed wiring board having a high reflectivity solder resist film formed using a thermosetting resin composition.

The printed wiring board includes (A) a carboxyl group-containing resin not having an aromatic ring, (B) a photopolymerization initiator containing at least one oxime ester photopolymerization initiator, (C) an epoxy compound, (D) rutile titanium oxide, and It is obtained by forming a soldering resist film using the white photocurable thermosetting resin composition characterized by including (E) diluent, and this white photocurable thermosetting resin composition.

Photocurable thermosetting resin composition, a soldering resist film, a printed wiring board, a photoinitiator

Description

Photocurable thermosetting resin composition and printed wiring board using the same {PHOTOCURABLE THERMOSETTING RESIN COMPOSITION AND PRINTED WIRING BOARD USING SAME}

INDUSTRIAL APPLICABILITY The present invention is suitable for use as a permanent mask of a printed wiring board, and is formed by image formation by developing with an aqueous alkali solution after exposure, and then photocurable thermosetting resin composition capable of forming a high reflectivity solder resist film by heat curing, and a circuit formed. It relates to a printed wiring board obtained by forming a soldering resist pattern using the composition on the printed wiring board surface.

The printed wiring board generally removes the unnecessary part of the copper foil bonded to the laminated board by etching, and forms the circuit wiring, and the electronic component is arrange | positioned at the predetermined place by soldering. The soldering resist film is used for manufacture of such a printed wiring board. That is, a soldering resist film is used as a protective film of a circuit at the time of soldering an electronic component. The solder resist film prevents adhesion of solder to unnecessary portions during soldering, and prevents the circuit conductor from being directly exposed to air and reacting with oxygen or moisture. It also functions as a permanent protective film of a circuit board. Therefore, various characteristics, such as adhesiveness, electrical insulation, solder heat resistance, solvent resistance, and chemical resistance, are calculated | required.

In addition, printed wiring boards have a method of miniaturization (fineness), multilayering, and one-boarding in order to realize high density, and mounting methods have also been shifted to surface mounting technology (SMT). For this reason, the demand for fine pinning, high resolution, high precision, and high reliability in the solder resist film is also increasing.

As a technique for forming a pattern of such a solder resist, the photoresist method capable of accurately forming a fine pattern is particularly mainstream due to an alkali development type photoresist due to environmental considerations.

For example, Patent Documents 1 and 2 disclose liquid resist ink compositions that can be developed with an aqueous alkali solution using a reaction product obtained by reacting an unsaturated monocarboxylic acid with a novolak-type epoxy resin and adding polybasic anhydride. Is disclosed.

On the other hand, in recent years, applications for directly mounting a light emitting diode (LED) emitting low power, such as a backlight of a liquid crystal display such as a portable terminal, a personal computer, a television, or a light source of a lighting fixture, on a printed wiring board on which a solder resist film is coated are increasing. .

Therefore, in order to utilize the light of LED efficiently, the printed wiring board which has the high reflectivity soldering resist film is calculated | required.

[Patent Document 1] Japanese Patent Laid-Open No. 1-54390

[Patent Document 2] Japanese Patent Publication No. 7-17737

It is thought that the high reflectivity soldering resist film can be formed using a white photocurable thermosetting resin composition. However, since the white photocurable thermosetting resin composition itself has a high reflectance, it is difficult to sufficiently absorb the light necessary for its curing when irradiated with light, making it difficult to form a pattern latent image accurately, Degrades.

Therefore, the objective of this invention is the photocurable thermosetting resin composition which can form the high reflectivity soldering resist film, and the white photocurable thermosetting resin composition which can form a pattern latent image correctly when irradiated with light, and this white It is providing the printed wiring board which has the high reflectivity soldering resist film formed using the photocurable thermosetting resin composition.

As a result of earnest research, the present inventors have included one or more oxime ester photopolymerization initiators as photopolymerization initiators, so that even when a white resin composition having a high reflectance is formed, the pattern latent image can be accurately formed when irradiated with light, and thus a good resolution I found myself having a last name. Furthermore, by using rutile type titanium oxide as a carboxyl group-containing resin and a white pigment having no aromatic ring, deterioration (yellowing) of the resin due to light resulting from the optical activity of the aromatic ring and titanium oxide of the resin can be suppressed, High reflectance can be achieved for a long time.

That is, according to the 1st aspect of this invention, (A) carboxyl group-containing resin which does not have an aromatic ring, (B) photoinitiator containing 1 or more types of oxime ester system photoinitiators, (C) epoxy compound, (D A white photocurable thermosetting resin composition comprising rutile type titanium oxide and (E) diluent is provided.

Moreover, according to another aspect of this invention, the printed wiring board obtained by forming the soldering resist film using the white photocurable thermosetting resin composition which concerns on the 1st side on the printed circuit board surface in which the circuit was formed is provided.

According to the present invention, it is a photocurable thermosetting resin composition which can form a high reflectivity solder resist film by using it as a solder resist, and when the light is irradiated, a white latent light having a good resolution since a pattern latent image can be accurately formed. The printed wiring board which has curable thermosetting resin composition and the soldering resist film which has a high reflectance formed using this photocurable thermosetting resin composition can be provided.

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

The white photocurable thermosetting resin composition of this invention is carboxyl group-containing resin which does not have (A) aromatic ring, (B) photoinitiator containing 1 or more types of oxime ester system photoinitiators, (C) epoxy compound, (D) rutile titanium oxide and (E) diluent.

As carboxyl group-containing resin (A) which does not have an aromatic ring, if it is resin which has a carboxyl group which does not have an aromatic ring, photosensitive carboxyl group-containing resin which has at least 1 photosensitive unsaturated double bond in itself, and photosensitive unsaturated double bond All of the carboxyl group-containing resins which do not have a compound can be used, and are not limited to specific ones. It is preferable that carboxyl group-containing resin (A) which does not have such an aromatic ring is carboxyl group-containing resin produced | generated from aliphatic polymerizable monomer. In addition, among the resins listed below, those having no aromatic ring (which may be either oligomers or polymers) can be preferably used. In other words,

(1) carboxyl group-containing resin obtained by copolymerization of a compound having an unsaturated carboxylic acid and an unsaturated double bond,

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

(3) A unsaturated monocarboxylic acid is reacted with a copolymer of a compound having one epoxy group and an unsaturated double bond and a compound having an unsaturated double bond in one molecule, and the saturated or unsaturated polybasic acid is reacted with the produced secondary hydroxyl group. Photosensitive carboxyl group-containing resin obtained by making anhydride react,

(4) The photosensitive hydroxyl group and carboxyl group-containing resin obtained by making a hydroxyl-containing polymer react with saturated or unsaturated polybasic acid anhydride, and then reacting the produced | generated carboxylic acid with the compound which has one epoxy group and unsaturated double bond in 1 molecule, respectively.

to be.

Among these, it has a carboxyl group obtained by reaction of the compound which has an oxirane ring and an ethylenically unsaturated group in (a) carboxyl group-containing (meth) acrylic copolymer resin which is photosensitive carboxyl group-containing resin of said (2), and (b) 1 molecule. Copolymer type resin is preferable.

The carboxyl group-containing (meth) acrylic copolymer resin of (a) 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 which comprises copolymer resin (a), methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, (Meth) acrylic-acid alkylesters, such as hexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, and caprolactone modified 2- Hydroxyl group-containing (meth) acrylic acid esters such as hydroxyethyl (meth) acrylate, methoxydiethylene glycol (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, isooctyloxydiethylene glycol (meth) acrylate, Glycol modified (meth) acrylates such as methoxy triethylene glycol (meth) acrylate and methoxy polyethylene glycol (meth) acrylate; and the like can be given. These may be used independently, or may mix and use 2 or more types. In addition, in this specification, a (meth) acrylate is a term used generically for an acrylate and a methacrylate, and it is the same also about another similar expression.

Moreover, as a compound which has one unsaturated group and one or more carboxyl groups in 1 molecule, the modified unsaturated monocarboxylic acid, for example (beta) -carboxyethyl, chain-stretched between acrylic acid, methacrylic acid, an unsaturated group, and a carboxylic acid is extended. Unsaturated monocarboxylic acid having an ester bond by (meth) acrylate, 2-acryloyloxyethyl succinic acid, 2-acryloyloxyethyl hexahydrophthalic acid, lactone modification, etc., modified unsaturated monocarboxylic acid having an ether bond Furthermore, what contains two or more carboxyl groups, such as maleic acid, in a molecule | numerator is mentioned. These may be used independently, or may mix and use 2 or more types.

(b) As a compound which has an oxirane ring and an ethylenically unsaturated group in 1 molecule, the compound which has an ethylenically unsaturated group and an oxirane ring in 1 molecule is preferable, For example, glycidyl (meth) acrylate and (alpha) -methylglycol. Cydyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 3,4-epoxycyclohexylethyl (meth) acrylate, 3,4-epoxycyclohexylbutyl (meth) acrylate, 3, 4- epoxycyclohexyl methyl amino acrylate etc. are mentioned. Among these, 3, 4- epoxycyclohexyl methyl (meth) acrylate is preferable. The compound which has an oxirane ring and ethylenically unsaturated group in these (b) 1 molecule may be used independently, and may mix and use 2 or more types.

Carboxyl group-containing resin (A) which does not have an aromatic ring needs to have the acid value in the range of 50-200 mgKOH / g. When the acid value is less than 50 mgKOH / g, it is difficult to remove the unexposed portion in the weak alkaline aqueous solution. When it exceeds 200 mgKOH / g, there exists a problem of the water resistance and electrical property of a cured film falling. 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. If the weight average molecular weight is less than 5,000, there is a tendency that the dry touch property is remarkably lowered. Moreover, since the problem that developability and storage stability will remarkably worsen when a weight average molecular weight exceeds 100,000 arises, it is unpreferable.

The oxime ester photoinitiator in the photoinitiator (B) containing at least one oxime ester photoinitiator used in the present invention is preferably a compound having a group represented by the following formula (I), and among these, thioxanthone Preference is given to compounds having a structure. As a compound which has such a thioxanthone structure, the compound of following formula (II) is mentioned.

<Formula I>

In the formula, R1 represents a hydrogen atom, an alkyl group having 1 to 7 carbon atoms, or an aryl group, and R2 represents an alkyl group having 1 to 7 carbon atoms, or an aryl group.

<Formula II>

By including an oxime ester system photoinitiator in the photoinitiator contained in the resin composition of this invention, even if it is a white photocurable thermosetting resin composition, a pattern latent image can be correctly formed when irradiated with light. As a photoinitiator of this invention, an oxime ester photoinitiator may be used independently and if it contains 1 or more types of oxime ester photoinitiators, it can also be used in combination with another photoinitiator. As another photoinitiator used with an oxime ester photoinitiator in this invention, benzoin and benzoin alkyl ether, such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, etc., are mentioned, for example. ; Acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, etc. Acetophenones; 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone- Aminoalkyl phenones such as 1,2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone; Anthraquinones such as 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, and 1-chloroanthraquinone; Ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; Benzophenones such as benzophenone; Xanthones; (2,6-dimethoxybenzoyl) -2,4,4-pentylphosphineoxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine jade Phosphine oxides, such as a seed and ethyl-2,4,6-trimethylbenzoylphenyl phosphinate: Various peroxides: A titanocene type initiator etc. are mentioned. The other photoinitiator used together with these oxime ester photoinitiators may be 1 type, or may be used in combination of 2 or more type.

Photoinitiator (B) containing at least one oxime ester photoinitiator of the present invention is N, N-dimethylaminobenzoic acid ethyl ester, N, N-dimethylaminobenzoic acid isoamyl ester, pentyl-4-dimethyl It can also be used together with photosensitizers, such as tertiary amines, such as aminobenzoate, a triethylamine, and a triethanolamine.

The compounding quantity of the photoinitiator (B) containing 1 or more types of oxime ester photoinitiators becomes like this. Preferably it is 1-30 mass parts with respect to 100 mass parts of carboxyl group-containing resin (A) which does not have an aromatic ring, More preferably, Is 2-25 mass parts. When the compounding quantity of the photoinitiator (B) containing 1 or more types of oxime ester system photoinitiators is less than 1 mass part, since photocurability falls and the pattern formation after exposure and image development becomes difficult, it is unpreferable. On the other hand, when it exceeds 30 mass parts, since thick film sclerosis | hardenability falls and a cost becomes expensive, it is unpreferable.

Subsequently, various epoxy resins can be used as an epoxy compound (C), For example, a bisphenol S-type epoxy resin, a diglycidyl phthalate resin, and triglycidyl isocyanurate (for example, Nissan Chemical Co., Ltd. make). TEPIC-H (β having a structure in which three epoxy groups are bonded in the same direction to the S-triazine ring backbone) or TEPIC (β having 2 different one epoxy group to the S-triazine ring backbone) A dicyclic agent such as a heterocyclic epoxy resin, a bixylenol epoxy resin, a biphenol epoxy resin, and a tetraglycidyl xylenoyl ethane resin) Adult epoxy resin, bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type resin, brominated bisphenol A type epoxy resin, phenol novolak type or cresolno Vololac type epoxy resin, alicyclic epoxy resin, bisphenol A novolak type epoxy resin, chelate type epoxy resin, glyoxal type epoxy resin, amino group containing epoxy resin, rubber modified epoxy resin, dicyclopentadiene phenolic epoxy resin, silicone And epoxy resins soluble in diluents such as modified epoxy resins and ε-caprolactone modified epoxy resins. These epoxy resins can be used individually or in combination of 2 or more types.

The compounding quantity of an epoxy compound (C) 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 carboxyl group-containing resin (A) which does not have an aromatic ring. When the compounding quantity of an epoxy compound (C) exceeds 70 mass parts, since the solubility of the unexposed part in a developing solution will fall and developing residue will become easy to produce, it is difficult to use it practically. On the other hand, when it is less than 5 mass parts, since the carboxyl group of carboxyl group-containing resin (A) remains in an unreacted state, it exists in the tendency which becomes difficult to fully acquire the electrical characteristics, solder heat resistance, and chemical-resistance of a cured coating film.

When the carboxyl group of the carboxyl group-containing resin (A) having no aromatic ring and the epoxy group of the epoxy compound (C) react by ring-opening polymerization, when an insoluble epoxy resin is used for the diluent (E) or another substance in the composition, Crosslinking tends to advance by heat. Therefore, when suppressing a crosslinking reaction and lengthening drying time, it is preferable to use independently a poorly water-soluble epoxy resin or in combination with an incompatible epoxy resin.

In the present invention, it is also one of the features to use rutile titanium oxide (D) as a white pigment. Anatase type titanium oxide is frequently used because of its higher whiteness than rutile type. However, since anatase type titanium oxide has photocatalytic activity, discoloration of resin in a photocurable thermosetting resin composition may arise. On the other hand, the rutile titanium oxide has a slightly lower whiteness than the anatase type, but has almost no optical activity, so that a stable solder resist film can be obtained. As a rutile titanium oxide (D), a well-known rutile type can be used. Specifically, Fuji Titan Kogyo Co., Ltd. TR-600, TR-700, TR-750, TR-840, Ishihara Sangyo Co., Ltd. R-550, R-580, R-630, R-820, CR -50, CR-60, CR-90, Titanium Co., Ltd. KR-270, KR-310, KR-380 etc. can be used.

The compounding quantity of rutile type titanium oxide (D) becomes like this. Preferably it is 50-300 mass parts, More preferably, it is 60-260 mass parts with respect to 100 mass parts of carboxyl group-containing resin (A) which does not have an aromatic ring. When the compounding quantity exceeds 300 mass parts, since photocurability falls and hardening depth will become low, it is unpreferable. On the other hand, if it is less than 50 mass parts, since hiding power is small, the soldering resist film of high reflectance cannot be obtained.

Moreover, in this invention, when silica particle (F) is used together, the photocurable thermosetting resin composition which has a deeper depth of cure can be obtained. This is considered to be because the refractive index of silica is relatively close to carboxyl group-containing resin (A) which does not have an aromatic ring.

As such a silica particle (F), a well-known thing can be used. For example, spherical silica (ad-matex-made admapa SO-E1, SO-E2, SO-E5 etc.), fine powder silicon oxide, amorphous silica, crystalline silica, fused silica, etc. are mentioned. These silica particles can be used alone or in combination of two or more thereof. The compounding quantity of a silica particle (F) becomes like this. Preferably it is 50-200 mass parts with respect to 100 mass parts of carboxyl group-containing resin (A) which does not have an aromatic ring.

As a diluent (E) used by this invention, a photopolymerizable monomer and / or the organic solvent are mentioned. 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 acrylates such as hexanediol, trimethylolpropanol, pentaerythritol, dipentaerythritol, tris-hydroxyethyl isocyanurate or ethylene oxide or propylene oxide adducts thereof; Acrylates such as phenoxyacrylate, bisphenol A diacrylate and ethylene oxide or propylene oxide adducts of these phenols: glycidyl ethers such as glycerin diglycidyl ether and trimethylolpropane triglycidyl ether Acrylates; Melamine acrylate; And / or methacrylates corresponding to the acrylates.

In addition, 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, etc. Glycol ethers; 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 diluent (E) as mentioned above can be used individually or as a mixture of 2 or more types. It is preferable to use 20-300 mass parts diluent (E) with respect to 100 mass parts of carboxyl group-containing resin (A) which does not have an aromatic ring. The purpose of the diluent is not only to make the photopolymerizable monomer easy to apply, but also to dilute the active energy ray-curable resin to enhance photopolymerization, while the organic solvent is dried to form a film. to be. Therefore, depending on the diluent to be used, either the contact method or the non-contact method of contacting a photomask to a coating film is used.

Moreover, in the white photocurable thermosetting resin composition of this invention, thermal deterioration and light deterioration can be further reduced by containing antioxidant and a hindered amine light stabilizer. The antioxidant is not particularly limited, but is preferably a hindered phenol compound. As a hindered phenol type compound, for example, knock lock 200, knock lock M-17, knock lock SP, knock lock SP-N, knock lock NS-5, knock lock NS-6, knock lock NS-30, knock lock 300, knock lock NS-7, knock lock DAH (all are manufactured by Ouchi Shinko 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 of the above are made 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 And Irganox 1425WL (all of which are manufactured by Ciba Specialty Chemical Co., Ltd.).

As the hindered amine light stabilizer, for example, tinubin 622LD, tinubin 144; CHIMASSORB 944LD and CHIMASSORB 119FL (both manufactured by Ciba Specialty Chemical Co., Ltd.); MARK LA-57, LA-62, LA-67, LA-63, LA-68 (all of which are manufactured by Adeka Gas Chemical Co., Ltd.); Sanol LS-770, LS-765, LS-292, LS-2626, LS-1114, LS-744 (all of which are manufactured by Sanchek Life Tech Co., Ltd.).

It is preferable to add 0.1-10 mass parts of said antioxidant and an optical stabilizer with respect to 100 mass parts of carboxyl group-containing resin (A) which does not have an aromatic ring.

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 used as needed.

The white photocurable thermosetting resin composition of this invention can be provided in liquid or paste form.

The white photocurable thermosetting resin composition of this invention is diluted as needed and adjusted to the viscosity suitable for a coating method. This is apply | coated to the printed wiring board in which the circuit was formed by the method of screen printing, curtain coating, spray coating, roll coating, etc., for example, by volatilizing the organic solvent contained in a composition at the temperature of 70-90 degreeC, A tack-free coating film can be formed. Then, the printed wiring board of this invention can be obtained by selectively exposing with active energy through a photomask, developing unexposed part with aqueous alkali solution, and forming a resist pattern. As aqueous alkali solution used here, 0.5-5 weight% sodium carbonate aqueous solution is common, but it is also possible to use other aqueous alkali solution. As another alkali aqueous solution, aqueous alkali solutions, such as potassium hydroxide, sodium hydroxide, potassium carbonate, sodium phosphate, sodium silicate, ammonia, amines, are mentioned, for example. As the irradiation light source for exposure, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultra high pressure mercury lamp, a xenon lamp, a metal halide lamp, or the like can be used. In addition, a laser beam etc. can also be used as an active ray.

In order to improve the heat resistance of the solder resist film obtained in this way, it is preferable to secondary-cure a solder resist film by heat, ultraviolet-ray, or far-infrared ray of 100-200 degreeC.

The soldering resist film formed using the photocurable thermosetting resin composition of this invention has high reflectivity, and has the property calculated | required by soldering resists, such as heat resistance, solvent resistance, and an electrical property. The soldering resist formed by this invention maintains high reflectance even after an accelerated degradation test.

<Example>

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

Synthesis of carboxyl group-containing resin having no aromatic ring

To a 2-liter flask equipped with a stirrer, a thermometer, a reflux cooler, a dropping funnel and a nitrogen inlet tube, 900 g of diethylene glycol dimethyl ether as a solvent, and t-butylperoxy 2-ethylhexanoate (Nippon) as a polymerization initiator 21.4 g of Perbutyl O) manufactured by Yushi Co., Ltd. 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 (Proxel FM1 manufactured by Daicel Chemical Industries, Ltd.) were added to bis as a polymerization initiator. A carboxyl group-containing copolymer resin was obtained by dropwise addition over 3 hours with 21.4 g of (4-t-butylcyclohexyl) peroxydicarbonate (manufactured by Nippon Yushi Co., Ltd., Perroyl TCP) and aged for 6 hours. . In addition, reaction was performed in nitrogen atmosphere.

Subsequently, 363.9 g of 3,4-epoxycyclohexyl methyl acrylate (Cyclomer A200 manufactured by Daicel Chemical Industries, Ltd.), 3.6 g of dimethylbenzylamine as a ring-opening catalyst, and hydroquinone monomethyl ether as a polymerization inhibitor were obtained on the obtained carboxyl group-containing copolymer resin. The ring-opening addition reaction of epoxy was performed by adding 1.80g, heating to 100 degreeC, and stirring. After 16 hours, a solution containing 53.8% by weight (nonvolatile content) of a carboxyl group-containing resin having no aromatic ring having an acid value of 108.9 mgKOH / g and a weight average molecular weight of 25,000 was obtained. Hereinafter, this reaction solution is called A-1 varnish.

Examples 1-6, Comparative Examples 1-6

Each component was mix | blended and stirred according to Table 1 and 2, it was made to disperse | distribute with a triaxial roll, and was set as the photocurable thermosetting resin composition, respectively. The numbers in the table represent parts by mass.

R820: Rutile type titanium oxide manufactured by Ishihara Sangyo

828: Bisphenol A epoxy resin made in Japan epoxy resin

SQ-E5: Admatex manufactured spherical silica

Initiator 1: 2- (acetyloxyiminomethyl) thioxanthene-9-one

          (Oxime ester system photoinitiator)

Initiator 2: Ciba Specialty Chemical Manufacture OXE02

          (Oxime ester system photoinitiator)

Initiator 3: IRGACURE 907 manufactured by Ciba Specialty Chemical

Initiator 4: Ciba Specialty Chemicals IRGACURE 369

Initiator 5: DAROCUR TPO manufactured by Ciba Specialty Chemical

Monomer: dipentaerythritol hexaacrylate

KS-66: Shin-Etsu Silicone Manufacturing Silicone Oil

Solvent: Carbitol Acetate.

In order to investigate the various properties of the soldering resist film formed using each photocurable thermosetting resin composition, it tested as follows and evaluated.

(1) resolution

Each photocurable thermosetting resin composition was beta-based using a 100 mesh polyester biased plate to a film thickness of 40 mm by screen printing on a FR-4 copper clad laminate having a size of 100 mm x 150 mm and 1.6 mm thick. Printed and dried in a hot air circulating drying furnace for 10 minutes at 80 ℃. Moreover, the photocurable thermosetting resin composition was repeatedly printed on each said dry coating film in the same way, and it dried at 80 degreeC for 20 minutes in the hot air circulation type drying furnace. The exposure machine for printed wiring boards was used, and HMW-680GW by Oak Seisakusho Co., Ltd. was used, and the ultraviolet-ray exposure was carried out by the accumulated light quantity of 500 mJ / cm <2> using the mask pattern which draws 80 micrometers and 100 micrometers lines. Thereafter, 1% sodium carbonate aqueous solution was used as a developing solution at 30 ° C. for 60 seconds using a developer for a printed wiring board, and then thermosetting was performed in a hot air circulation drying furnace at 150 ° C. for 60 minutes to prepare a test piece. The line width which remained in this test piece was confirmed, and it was set as the evaluation of resolution. The results are shown in Tables 3 and 4. (Circle) and the case where the line of 100 micrometers remain | survived in the case where an 80-micrometer line remain | survived among these were made into (circle) and the case where the line of 100 micrometers did not remain.

As apparent from Table 3, it was found that in Examples 1 to 6 using the photocurable thermosetting resin composition of the present invention containing at least one oxime ester photopolymerization initiator, good resolution is obtained. On the other hand, Comparative Examples 1-3 which do not contain the oxime ester type photoinitiator of Table 4 contain the initiator of the same quantity as the photoinitiator amount contained in an Example, but a line does not remain after image development, and favorable resolution is achieved. I knew it was not. Therefore, in Comparative Examples 4 to 6, a double amount of photopolymerization initiator was used for the purpose of improving resolution, but even in this case, no line remained after development.

(2) light resistance

The photocurable thermosetting resin composition of Examples 1 to 6 was plated of 100 mesh polyester bias so that the film thickness was 40 μm by screen printing on a FR-4 copper clad laminate having a size of 100 mm × 150 mm and a 1.6 mm thickness. Was printed in a beta pattern, and dried in a hot air circulation drying furnace at 80 ° C. over 30 minutes. The exposure machine for printed wiring boards was used, and HMW-680GW by Oak Seisakusho Co., Ltd. was exposed to ultraviolet light at a cumulative light amount of 500 mJ / cm 2 so as to leave a negative pattern of 30 mm 2. Thereafter, 1% sodium carbonate aqueous solution was used as a developing solution at 30 ° C. for 60 seconds using a developer for a printed wiring board, and then thermosetting was performed in a hot air circulation drying furnace at 150 ° C. for 60 minutes to prepare a test piece for characteristic tests.

The obtained test piece was measured with the Minolta color chromaticity meter CR-400. Thereafter, 50 J / cm 2, 100 J / cm 2, and 150 J / cm 2 of light were irradiated with a UV conveyor (output 150 W / cm metal halide lamp cold mirror) to accelerate deterioration. The results are shown in Tables 5 and 6.

In Table 5, Y represents the reflectance of the XYZ color system, and L * represents the brightness of the L * a * b * color system. a * represents a red direction, -a * represents a green direction, b * represents a yellow direction, -b * represents a blue direction, and it is closer to 0 that there is no saturation. ΔE * ab indicates the change in color. The smaller this value, the smaller the change in color. About visual evaluation items, (circle) shows no discoloration, (circle) shows almost no discoloration, (triangle | delta) has a little discoloration, and x shows that there is a clear discoloration.

As is apparent from Table 5, in Examples 1 to 6 using the composition of the present invention, even after accelerated degradation, the reflectance does not significantly decrease, the change in brightness is small, and the value of ΔE * ab, which is a change in color, is small. Could know. In addition, there is little or no discoloration even in visual evaluation.

From Table 6, in Comparative Examples 4 to 6 using the photopolymerization initiator in the doubled amount of the examples, both the reflectance Y and the brightness L * after acceleration deterioration became low values, and the value of ΔE * ab which is a change in color is also large. In addition, discoloration is also observed by visual evaluation. From this, it was found that not only the resolution was improved but also the light resistance was lowered even when using a double amount of the photopolymerization initiator.

(3) heat resistance

The rosin-type flux was apply | coated to each test piece manufactured similarly to (2), and it flowed for 10 second in the solder tank of 260 degreeC. Then, after wash | cleaning with propylene glycol monomethyl ether acetate and drying, the peel test with the cellophane adhesive tape was done and the peeling of a coating film was evaluated. The results are shown in Tables 7 and 8. Here, (circle) shows that there is no peeling of a coating film, and x shows that there exists peeling of a coating film.

(4) solvent resistance

Each test piece prepared in the same manner as in (2) was immersed in propylene glycol monomethyl ether acetate for 30 minutes and dried, and then subjected to a peel test with a cellophane adhesive tape to evaluate peeling and discoloration of the coating film. The results are shown in Tables 7 and 8 together. Here, (circle) shows that there is no peeling or discoloration of a coating film, and x shows that there is peeling or discoloration of a coating film.

(5) pencil hardness test

To each test piece produced as in (2), the pencil of B-9H polished so that the tip of the shim was flattened at an angle of about 45 °, and the hardness of the pencil without peeling of the coating film was recorded. The results are shown in Tables 7 and 8 together.

(6) insulation resistance test

The test piece was manufactured on the conditions similar to (2) except having used the comb-shaped electrode B coupon of IPC B-25 test pattern instead of FR-4 copper clad laminated board. A bias of 500 V DC was applied to this test piece, and the insulation resistance value was measured. The results are shown in Tables 7 and 8 together.

As is apparent from Table 7, in Examples 1 to 6 using the photocurable thermosetting resin composition of the present invention, it was found that it had good heat resistance, solvent resistance, adhesiveness, and electrical insulation required for the solder resist film.

From the above results, it was found that by including the oxime ester photopolymerization initiator in the photopolymerization initiator, high resolution was obtained in the state of maintaining good light resistance, heat resistance, solvent resistance, adhesiveness, and electrical insulating properties.

As mentioned above, according to this invention, the white photocurable thermosetting resin composition which can form the high reflectivity soldering resist film can be obtained. The white photocurable thermosetting resin composition of this invention can form a pattern latent image correctly, when it irradiates light, and has favorable resolution.

Claims (7)

(A) Carboxyl group-containing resin which does not have an aromatic ring, (B) The photoinitiator containing at least 1 type of oxime ester photoinitiator, (C) epoxy compound, (D) rutile titanium oxide, and (E) diluent White photocurable thermosetting resin composition characterized by including. The carboxyl group-containing resin (A) having no aromatic ring according to claim 1 is reacted by (a) a carboxyl group-containing (meth) acrylic copolymer resin and (b) a compound having an oxirane ring and an ethylenically unsaturated group in one molecule. It is copolymer type resin which has a carboxyl group obtained, The white photocurable thermosetting resin composition characterized by the above-mentioned. The white photocurable thermosetting resin composition 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. The white photocurable thermosetting resin composition according to claim 1, wherein the oxime ester photoinitiator has a thioxanthone structure. (F) Silica particle is further included, The white photocurable thermosetting resin composition of Claim 1 characterized by the above-mentioned. The white photocurable thermosetting resin composition according to any one of claims 1 to 4, wherein the photocurable thermosetting resin composition is a solder resist composition. The printed wiring board obtained by forming a soldering resist film using the white photocurable thermosetting resin composition of any one of Claims 1-5 on the printed wiring board surface in which the circuit was formed.