TWI484290B - Solder resist composition and printed wiring board - Google Patents

Description

Solder resist composition and printed wiring board

The present invention relates to a solder resist composition which can form a high reflectance solder resist for a permanent mask used as a printed wiring board, and on a surface of a printed wiring board on which a circuit is formed, using the solder resist composition to form Printed wiring board made of solder resist pattern.

The printed wiring board is generally formed by etching away unnecessary portions of the copper foil bonded to the laminate to form a circuit harness, and the electronic component can be disposed in a predetermined place by soldering. Such a printed wiring board is a protective film which can be formed by hardening a base material and then hardening it as a circuit for attaching solder to an electronic component.

This solder resist is attached to the solder to prevent the solder from adhering to unnecessary portions while preventing the circuit conductor from being directly exposed to the air and being deteriorated by oxygen or moisture components. Further, the solder resist has a function as a permanent protective film of the circuit board. Therefore, the solder resist is required to have properties such as adhesion, electrical insulation, solder heat resistance, solvent resistance, and chemical resistance.

In addition, in order to achieve high density, the printed wiring board has been specialized in miniaturization (fineness), multi-layering, and onboard, and has continued to be developed in surface mounting technology (SMT) in the mounting method. Therefore, in terms of solder resist, the requirements for refinement, high resolution, high precision, and high reliability have also increased.

In the patterning technique for forming such a solder resist, a photolithography method capable of accurately forming a fine pattern is used, particularly from the viewpoint of environmental aspects, and the photolithography method using an alkali developing type is mainly used.

For example, Patent Literature 1 and Patent Document 2 disclose a solder resist composition which is obtained by reacting a novolac type epoxy resin with an unsaturated monocarboxylic acid and then adding a polybasic acid anhydride. The reaction product is used as a base polymer to form a solder resist composition which can be developed in an aqueous alkali solution.

On the other hand, in recent years, backlights for liquid crystal displays such as mobile phone terminals, personal computers, and televisions, and light sources for lighting devices have been newly added to light-emitting diodes (LEDs) that emit light with low power. It is used in a printed wiring board formed by coating a solder resist.

For this purpose, in order to utilize the light of the LED more efficiently, in order to have a high reflectance of the solder resist, it is required to have a printed wiring board in which the solder resist is white.

However, the white solder resist has a high reflectance due to the composition itself, and reflects light when the pattern is exposed, so that the light necessary for the hardening cannot be sufficiently absorbed, and as a result of deterioration in resolution, It is difficult to form a high-definition pattern latent image.

Further, the printed wiring board in which the LED is directly mounted promotes deterioration and coloration of the white solder resist due to light and heat emitted from the LED, resulting in a decrease in reflectance.

[Previous Technical Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Publication No. 1-54390

[Patent Document 2] Special Fair 7-17737

An object of the present invention is to provide a solder resist composition and a printed wiring board which can efficiently use LED light and which provide a high resolution anti-flux film with high reflectance.

Further, an object of the present invention is to provide a solder resist composition and a printed wiring board which can prevent deterioration and coloring of a solder resist due to light and heat from an LED.

As a result of repeated investigations by the present inventors, it has been found that a resin having a thermosetting non-aromatic ring is used as a carboxyl group-containing resin by using alkali-developable, and rutile for achieving high reflectance is used. As a white pigment, the titanium oxide can suppress deterioration due to light or heat for a long period of time, and by using a bis-indenylphosphine oxide-based photopolymerization initiator together with a monofluorenylphosphine oxide-based photopolymerization initiator. As a photopolymerization initiator, even a large amount of a solder resist composition containing a rutile type titanium oxide having a high reflectance can form a latent image having excellent resolution and high definition.

That is, the solder resist composition of the present invention contains (A) a carboxyl group-containing resin having no aromatic ring, (B) a bis-indenylphosphine oxide-based photopolymerization initiator, and (C) a monodecylphosphine oxide. a photopolymerization initiator, (D) a photopolymerizable monomer, (E) rutile type titanium oxide, and (G) an organic solvent, and may further contain (F) an epoxy compound or (H) thiophene. Thioxanthone is a photopolymerization sensitizer.

According to the present invention, it is possible to form a characteristic having coating properties, photocurability, developability, solder heat resistance, adhesion, electrical insulation, and the like which are required as development-type solder resists, and further suppressable A decrease in reflectance due to the passage of time and deterioration result in a high-reflectivity solder resist film which can be colored with high reflectance. Furthermore, the solder resist composition of the present invention can enhance the overall illuminance when an LED is mounted on a printed wiring board.

[Formation of the Invention]

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

The solder resist composition of the present invention comprises (A) a carboxyl group-containing resin having no aromatic ring, (B) a bis-indenylphosphine oxide-based photopolymerization initiator, and (C) a monodecylphosphine oxide-based photopolymerization. The initiator, (D) photopolymerizable monomer, (E) rutile type titanium oxide, and (G) organic solvent are characterized by further containing (F) epoxy compound or (H) thioxantate Ketone photopolymerization sensitizer.

(carboxyl-containing resin without aromatic ring)

In the case of the carboxyl group-containing resin (A) having no aromatic ring, a photosensitive carboxyl group-containing resin having one or more photosensitive unsaturated double bonds in itself and a photosensitive unsaturated double bond-containing resin may be used. Any of the carboxyl group resins is not specified. In particular, it is suitable to use an aromatic ring (either an oligomer or a polymer) in the resin to be used. That is, (1) a carboxyl group-containing resin obtained by copolymerization of a compound having an unsaturated carboxylic acid and an unsaturated double bond, and (2) a carboxyl group-containing (meth)acrylic copolymer resin, in one molecule a photosensitive carboxyl group-containing resin obtained by reacting a compound having an epoxy group and an ethylenically unsaturated group, (3) a compound having one epoxy group and an unsaturated double bond in one molecule and having an unsaturated double a photosensitive carboxyl group-containing resin obtained by reacting a saturated monocarboxylic acid with a copolymer of a bond, and reacting a saturated or unsaturated polybasic acid anhydride on a second-order hydroxyl group formed by the reaction, (4) A compound having one epoxy group and one unsaturated double bond in one molecule on a carboxylic acid formed by the reaction after reacting a saturated or unsaturated polybasic acid anhydride on a hydroxyl group-containing polymer A photosensitive resin containing a hydroxyl group and a carboxyl group obtained by the reaction.

Among these, (a) the carboxyl group-containing (meth)acrylic copolymer resin of (a) the photosensitive carboxyl group-containing resin, and (b) one molecule having an epoxy group and an ethyl group are not A copolymerized resin having a carboxyl group obtained by a reaction of a compound of a saturated group is preferred.

The carboxyl group-containing (meth)acrylic copolymer resin (a) is obtained by copolymerizing a (meth) acrylate with a compound having one unsaturated group and at least one carboxyl group in one molecule. Examples of the (meth) acrylate constituting the copolymer resin (a) include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and butyl (methyl). ) alkyl (meth)acrylates such as acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, hydroxy propyl (methyl) The hydroxy group of acrylate, hydroxybutyl (meth) acrylate, caprolactone-modified 2-hydroxyethyl (meth) acrylate, etc. contains (meth) acrylates, methoxy diethylene glycol ( Methyl) acrylate, ethoxy diethylene glycol (meth) acrylate, isooctyloxy diethylene glycol (meth) acrylate, phenoxy triethylene glycol (meth) acrylate, A A diol-modified (meth) acrylate such as oxytriethylene glycol (meth) acrylate or methoxy polyethylene glycol (meth) acrylate. These may be used singly or in combination of two or more. In the present specification, the term "(meth)acrylate" refers to a general term for acrylate and methacrylate, and other similar performances are also the same.

Further, in the case of a compound having one unsaturated group and at least one carboxyl group in one molecule, a modified monocarboxylic acid which is chain-extended between acrylic acid, methacrylic acid, an unsaturated group and a carboxylic acid may, for example, be mentioned. --carboxyethyl (meth) acrylate, 2-propenyl methoxyethyl succinic acid, 2-propenyl methoxyethyl hexahydrophthalic acid, ester linkage modification by lactone modification, etc. The unsaturated monocarboxylic acid, the modified unsaturated monocarboxylic acid having an ether bond, or the carboxyl group having two or more maleic acids in the molecule, or the like. These may be used singly or in combination of two or more.

(b) A compound having an epoxy group and an ethylenically unsaturated group in one molecule, and may be a compound having an ethylenically unsaturated group and an epoxy group in one molecule, and examples thereof include a glycidyl group (methyl group). Acrylate, α-methylepoxypropyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 3,4-epoxycyclohexylethyl (methyl) Acrylate, 3,4-epoxycyclohexylbutyl (meth) acrylate, 3,4-epoxycyclohexylmethyl methacrylate, and the like. Among them, 3,4-epoxycyclohexylmethyl (meth) acrylate is preferred. The compound having an epoxy group and an ethylenically unsaturated group in the above (b) molecule may be used singly or in combination of two or more.

The carboxyl group-containing resin (A) having no aromatic ring must have an acid value in the range of 50 to 200 mgKOH/g. When the acid value is less than 50 mgKOH/g, the unexposed portion of the coating film of the solder resist composition in the weak alkali aqueous solution is difficult to remove. When the acid value exceeds 200 mgKOH/g, there is a problem that water resistance and electrical properties of the cured film are poor. Further, the weight average molecular weight of the carboxyl group-containing resin (A) having no aromatic ring is preferably in the range of 5,000 to 100,000. When the weight average molecular weight is less than 5,000, the touch drying property of the coating film of the solder resist composition tends to be remarkably deteriorated. When the weight average molecular weight exceeds 100,000, the development of the solder resist composition and the storage stability may be remarkably deteriorated.

(photopolymerization initiator)

(bis-decyl phosphine oxide photopolymerization initiator)

The bis-indenylphosphine oxide-based photopolymerization initiator (B) used in the present invention may, for example, be bis-(2,6-dichlorobenzhydryl)phenylphosphine oxide or bis(2,6-di). Chlorobenzylidene)-2,5-dimethylphenylphosphine oxide, bis-(2,6-dichlorobenzylidene)-4-propylphenylphosphine oxide, bis-(2,6- Dichlorobenzhydryl)-1-naphthylphosphine oxide, bis-(2,6-dimethoxybenzylidene)phenylphosphine oxide, bis-(2,6-dimethoxybenzonitrile -2,4,4-trimethylpentylphosphine oxide, bis-(2,6-dimethoxybenzylidene)-2,5-dimethylphenylphosphine oxide, bis-(2 , 4,6-trimethylbenzimidyl)phenylphosphine oxide, (2,5,6-trimethylbenzylidene)-2,4,4-trimethylpentylphosphine oxide, and the like. Among them, bis-(2,4,6-trimethylbenzylidene)phenylphosphine oxide (manufactured by Ciba Japan Co., Ltd., trade name; IRUGACURE 819) is easily available and is practical.

(monomethyl phosphine oxide photopolymerization initiator)

The monoterpene phosphine oxide-based photopolymerization initiator (C) used in the present invention may, for example, be 2,4,6-trimethylbenzimidyldiphenylphosphine oxide or 2,6-dimethoxy Benzobenzyldiphenylphosphine oxide, 2,6-dichlorobenzhydryldiphenylphosphine oxide, 2,4,6-trimethylbenzimidylphosphonic acid methyl ester, 2- Methyl benzhydryl diphenyl phosphine oxide, isopropyl trimethyl ethyl phenyl phosphonate, and the like. Among them, 2,4,6-trimethylbenzimidyldiphenylphosphine oxide (manufactured by Ciba Japan Co., Ltd., trade name; DAROCURE TPO) is easily available and is practical.

The solder resist composition of the present invention is a combination of the above-mentioned bis-indenylphosphine oxide-based photopolymerization initiator (B) and the above-mentioned monofluorenylphosphine oxide-based photopolymerization initiator (C), even if it is compounded with titanium oxide. The high reflectivity coating film also absorbs the necessary light to form a high-definition pattern. It is also possible to finely adjust the light absorption of the coating film by changing the mixing ratio. That is, when the cross-sectional shape of the pattern is likely to be undercut due to insufficient deep hardenability on the surface side of the substrate, the above-mentioned bis-indenylphosphine oxide-based photopolymerization initiator (B) The ratio becomes larger. In addition, when the surface hardening property is insufficient and the surface state is poor after development, the ratio of the monothiophosphine oxide-based photopolymerization initiator (C) is increased. The ratio of the bis-indenylphosphine oxide-based photopolymerization initiator (B) to the mono-fluorenylphosphine oxide-based photopolymerization initiator (C) is from 90:10 to 1:99, preferably from 80:20 to 2. :98. If it is outside the range of the matching ratio, the effect of the combined use becomes small, and the necessary light cannot be absorbed, so that a high-definition pattern cannot be formed.

The total amount of the bis-indenylphosphine oxide-based photopolymerization initiator (B) and the mono-fluorenylphosphine oxide-based photopolymerization initiator (C) is 100 parts by mass of the carboxyl group-containing resin (A) having no aromatic ring. In other words, it is preferably 1 to 30 parts by mass, more preferably 2 to 25 parts by mass. When the total amount of the bis-indenylphosphine oxide-based photopolymerization initiator (B) and the mono-fluorenylphosphine oxide-based photopolymerization initiator (C) is less than 1 part by mass, photocurability is lowered, and exposure is performed. The pattern of the latter is difficult to form. On the other hand, when the total amount is more than 30 parts by mass, the coloring of the coating film derived from the photopolymerization initiator becomes large, and the reason for the increase in cost is not preferable.

(photopolymerizable monomer)

The photopolymerizable monomer (D) used in the present invention may, for example, be a hydroxyalkyl acrylate such as 2-hydroxyethyl acrylate or 2-hydroxybutyl acrylate; or ethylene glycol or methoxytetra a mono- or diacrylate of a glycol such as ethylene glycol, polyethylene glycol or propylene glycol; an acrylamide such as N,N-dimethyl decylamine or N-methylol acrylamide; Aminoalkyl acrylates such as N-dimethylaminoethyl acrylate; polyols such as hexanediol, trimethylolpropane, pentaerythritol, dipentaerythritol, and para-hydroxyethyltrimeric isocyanic acid Or such polyvalent acrylates of ethylene oxide or propylene oxide adducts; acrylates of phenoxy acrylate, bisphenol A diacrylate and phenolic ethylene oxide or propylene oxide adducts thereof An acrylate of a glycidyl ether such as glycerol diepoxypropyl ether or trimethylolpropane triepoxypropyl ether; melamine acrylate; and/or a corresponding acrylate Acrylates and the like.

The amount of the photopolymerizable monomer (D) is preferably from 10 to 100 parts by mass, more preferably from 20 to 80 parts by mass per 100 parts by mass of the carboxyl group-containing resin (A) having no aromatic ring. Share. When the amount is more than 100 parts by mass, the physical properties of the solder resist as a hard coating film may be lowered. On the other hand, if the amount is less than 10 parts by mass, sufficient photocurability is not obtained, and a high-definition pattern cannot be obtained.

(rutile type titanium oxide)

In the present invention, in the case of a white pigment, rutile type titanium oxide (E) is used. Typical titanium oxides are anatase type and rutile type. Anatase type titanium oxide has photocatalytic activity, which causes discoloration of the resin in the solder resist composition. On the other hand, the rutile-type titanium oxide is absorbed in the vicinity of the boundary between the ultraviolet region and the visible region as compared with the anatase-type titanium oxide, and the reflectance of the entire whiteness and visible light regions is obtained. Although it is poor in appearance, a stable solder resist film can be obtained because there is almost no photoactivity.

As the rutile type titanium oxide (E), a known one can be used. Specifically, Tipaque R-820, Tipaque R-830, Tipaque R-930, Tipaque R-550, Tipaque R-630, Tipaque R-680, Tipaque R-670, Tipaque R-680, Tipaque R- can be used. 670, Tipaque R-780, Tipaque R-850, Tipaque CR-50, Tipaque CR-57, Tipaque CR-80, Tipaque CR-90, Tipaque CR-93, Tipaque CR-95, Tipaque CR-97, Tipaque CR- 60, Tipaque CR-63, Tipaque CR-67, Tipaque CR-58, Tipaque CR-85, Tipaque UT771 (made by Ishihara Sangyo Co., Ltd.), TI-PURE R-100, TI-PURE R-101, TI-PURE R -102, TI-PURE R-103, TI-PURE R-104, TI-PURE R-105, TI-PURE R-108, TI-PURE R-900, TI-PURE R-902, TI-PURE R- 960, TI-PURE R-706, TI-PURE R-931 (manufactured by Du Pont AG), TITON R-25, TITON R-21, TITON R-32, TITON R-7E, TITON R-5N, TITON R -61N, TITON R-62N, TITON R-42, TITON R-45M, TITON R-44, TITON R-49S, TITON GTR-100, TITON GTR-300, TITON D-918, TITON TCR-29, TITON TCR -52, TITON FTR-700 (manufactured by Dai Chemical Industry Co., Ltd.), etc.

The amount of the rutile-type titanium oxide (E) is preferably 50 to 450 parts by mass, more preferably 60 to 100 parts by mass of the carboxyl group-containing resin (A) having no aromatic ring. 350 parts by mass. When the amount of the blending exceeds 450 parts by mass, the photocurability is lowered and the hardening depth is lowered. On the other hand, if the amount is less than 50 parts by mass, the hiding power is small, and a high reflectance solder resist cannot be obtained.

(epoxy compound)

Next, as the epoxy compound (F), for example, a bisphenol S type epoxy resin, a diglycidyl phthalate resin, or a trisuccinyl isocyanate (for example, Nissan Chemical Co., Ltd.) TEPIC-H (β-body with three epoxy-bonded structures in the same direction for S-triazine ring bones) or TEPIC (β- and S-triazine ring-gland) a heterocyclic epoxy resin, a bixylenol type epoxy resin, a biphenyl having one epoxy group bonded to an α-form having a structure different from the other two epoxy groups) Epoxy resin, tetraepoxypropyl dimethyl phenol ethane resin, etc., which are poorly soluble in the diluent, or bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F Type resin, odorous bisphenol A type epoxy resin, phenol novolac type or cresol novolac type epoxy resin, alicyclic epoxy resin, bisphenol A novolak type epoxy resin, chelating epoxy Resin, glyoxal type epoxy resin, amine group containing epoxy resin, rubber modified epoxy resin, dicyclopentadiene novolac type epoxy resin, anthrone modified epoxy resin ε- caprolactone-modified epoxy resin of an epoxy resin was soluble in the diluent. These epoxy resins may be used singly or in combination of two or more.

The amount of the epoxy compound (F) to be used is preferably from 5 to 70 parts by mass, more preferably from 5 to 60 parts by mass, per 100 parts by mass of the carboxyl group-containing resin (A) having no aromatic ring. When the amount of the epoxy compound (F) is more than 70 parts by mass, the solubility of the unexposed portion in the developing solution is lowered, and development of the image is liable to occur, which is practically difficult to use. On the other hand, if the amount is less than 5 parts by mass, the carboxyl group of the carboxyl group-containing resin (A) having no aromatic ring may remain in an unreacted state, resulting in failure of the cured coating film to obtain sufficient electrical properties, solder heat resistance. Sex and chemical resistance.

The carboxyl group of the carboxyl group-containing resin (A) having no aromatic ring and the epoxy group of the epoxy compound (F) are reacted by ring-opening polymerization. Further, when a readily soluble epoxy resin is used as the organic solvent (G) or other substance in the solder resist composition, crosslinking of a carboxyl group and an epoxy group is liable to progress due to heat during drying. Therefore, when it is intended to suppress the crosslinking reaction and prolong the drying time, it is expected to use a poorly soluble epoxy resin alone or in combination with an easily soluble epoxy resin.

(Organic solvents)

The organic solvent (G) used in the present invention is a state in which the solder resist composition is easily applied, and is applied to a substrate or the like and then dried to form a coating film. Examples of such an organic solvent (G) include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; methyl stilbene and ethyl赛路苏, butyl 赛路苏, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, diethylene glycol monoethyl ether, dipropylene glycol monoethyl ether, triethylene glycol monoethyl a glycol ether such as an ether; an ester of an ethyl acetate, a butyl acetate, a celecoxime acetate, a diethylene glycol monoethyl ether acetate, and an esterified product of the above 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 gas oil, hydrogenated petroleum gas oil, and solvent light oil.

The organic solvent (G) may be used singly or in combination of two or more. The amount of the organic solvent (G) is preferably 20 to 300 parts by mass based on 100 parts by mass of the carboxyl group-containing resin (A) having no aromatic ring.

(thioxanthone photopolymerization sensitizer)

In the present invention, it is preferred to use a thioxanthone-based photopolymerization sensitizer (H) for the purpose of improving the light sensitivity at the time of exposure. Further, the composition of the above-mentioned bis-indenylphosphine oxide-based photopolymerization initiator (B) and the above-mentioned monofluorenylphosphine oxide-based photopolymerization initiator (C) is a thioxanthone-based photopolymerization sensitizer (H). The effect is very high. Examples of the thioxanthone-based photopolymerization sensitizer (H) include thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, and 2,4- Dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, and the like.

The amount of the thioxanthone-based photopolymerization sensitizer (H) is preferably 0.05 to 2 parts by mass, more preferably 0.1 to 100 parts by mass of the carboxyl group-containing resin (A) having no aromatic ring. ~1 part by mass. When the amount is less than 0.05 parts by mass, the effect of the sensitivity upward is small, and when it exceeds 2 parts by mass, the color of the coating film derived from thioxanthone becomes large.

(other ingredients)

(stabilizer)

Further, in the solder resist composition of the present invention, photodegradation can be reduced by containing a hindered amine light stabilizer.

Examples of the hindered amine-based light stabilizers include TINUVIN 622LD, TINUVIN 144, CHIMASSORB 944LD, and CHIMASSORB 119FL (all of which are manufactured by Ciba Japan Co., Ltd.); MARK LA-57, LA-62, LA-67, LA-63, LA-68 (all of which are manufactured by the company ADEKA); Sanol LS-770, LS-765, LS-292, LS-2626, LS-1114, LS-744 (all of which are manufactured by LIFE TECH AG).

The light stabilizer is preferably added in an amount of 0.1 to 10 parts by mass based on 100 parts by mass of the carboxyl group-containing resin (A) having no aromatic ring.

(Dispersant)

In the solder resist composition of the present invention, the dispersibility and sedimentation property of titanium oxide can be improved by containing a dispersant. As the dispersing agent, for example, ANTI-TERRA-U, ANTI-TERRA-U100, ANTI-TERRA-204, ANTI-TERRA-205, DISPERBYK-101, DISPERBYK-102, DISPERBYK-103, DISPERBYK-106, DISPERBYK-108 DISPERBYK-109, DISPERBYK-110, DISPERBYK-111, DISPERBYK-112, DISPERBYK-116, DISPERBYK-130, DISPERBYK-140, DISPERBYK-142, DISPERBYK-145, DISPERBYK-161, DISPERBYK-162, DISPERBYK-163, DISPERBYK -164, DISPERBYK-166, DISPERBYK-167, DISPERBYK-168, DISPERBYK-170, DISPERBYK-171, DISPERBYK-174, DISPERBYK-180, DISPERBYK-182, DISPERBYK-183, DISPERBYK-185, DISPERBYK-184, DISPERBYK-2000 DISPERBYK-2001, DISPERBYK-2009, DISPERBYK-2020, DISPERBYK-2025, DISPERBYK-2050, DISPERBYK-2070, DISPERBYK-2096, DISPERBYK-2150, BYK-P104, BYK-P104S, BYK-P105, BYK-9076, BYK -9077, BYK-220S (manufactured by BYK Japan Co., Ltd.), DISPARLON 2150, DISPARLON 1210, DISPARLON KS-860, DISPARLON KS-873N, DISPARLON 7004, DISPARLON 1830, DISPARLON 1860, DISPARLON 1850, DISPARLON DA-400N, DISPARLON PW- 36. DISPARLON DA-7 03-50 (made by Kanemoto Kasei Co., Ltd.), FLOWLEN G-450, FLOWLEN G-600, FLOWLEN G-820, FLOWLEN G-700, FLOWLEN DOPA-44, FLOWLEN DOPA-17 (manufactured by Kyoeisha Chemical Co., Ltd.).

In order to achieve the above object, the content of the dispersant is 0.1 to 10 parts by mass, preferably 0.5 to 5 parts by mass, per 100 parts by mass of the rutile type titanium oxide (E).

(other added ingredients)

Further, in the solder resist composition of the present invention, a hardening accelerator, a thermal polymerization inhibiting agent, a tackifier, an antifoaming agent, a leveling agent, a coupling agent, a flame retardant auxiliary, or the like may be used as needed.

(method of law)

Hereinafter, the use of the solder resist composition will be described with respect to the manufacture of the printed wiring board.

First, the solder resist composition of the present invention is diluted as needed to adjust the viscosity to a suitable coating method.

Next, the viscosity-adjusted composition is applied to a printed wiring board on which a circuit is formed by a screen printing method, a curtain coating method, a spray coating method, a roll coating method, or the like. Then, at a temperature of, for example, 70 to 90 ° C, a coating film which is a tack-free film is formed by volatilizing and drying the organic solvent contained in the applied composition.

Thereafter, the coating film is selectively exposed through an active energy ray through a photomask, and the unexposed portion is developed by an aqueous alkali solution to form a photoresist pattern. Then, this photoresist pattern is formed into a solder resist pattern by thermal hardening at 100 ° C to 200 ° C.

For the 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, or a metal halide lamp can be used. Others, it is also possible to use laser light or the like as the active light.

In the case of the aqueous alkali solution of the developing solution, an aqueous sodium carbonate solution of 0.5 to 5% by mass is generally used, and other aqueous alkali solutions may also be used. Examples of the other aqueous alkali solution include aqueous alkali solutions such as potassium hydroxide, sodium hydroxide, potassium carbonate, sodium phosphate, sodium citrate, ammonia, and amines.

Then, after forming a solder resist pattern, LEDs are mounted to manufacture the printed wiring board of the present invention. The printed wiring board of the present invention is produced by using a solder resist containing titanium oxide having a high reflectance of the present invention, and has a high reflectance and a high-definition pattern.

[Examples]

Hereinafter, the present invention will be specifically described by showing examples and comparative examples, but the present invention is not limited thereto.

(A) Synthesis of a carboxyl group-containing resin having no aromatic ring

Synthesis Example 1

In a 2-liter separable flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel, and a nitrogen introduction tube, 900 g of diethylene glycol dimethyl ether as a solvent and t-butyl group as a polymerization initiator were placed. Peroxy 2-ethylhexanoate (made by Nippon Oil Co., Ltd., trade name; O) After 21.4 g, heat to 90 °C. After heating, 309.9 g of methacrylic acid, 116.4 g of methyl methacrylate, and 2-hydroxyethyl methacrylate modified by lactone (manufactured by DAICEL Chemical Industry Co., Ltd., trade name; PLACCEL FM1) 109.8 g (4-t-butylcyclohexyl)peroxydicarbonate with a polymerization initiator (manufactured by Nippon Oil Co., Ltd., trade name; TCP) 21.4g together, added for 3 hours to add. This was further aged for 6 hours to obtain a carboxyl group-containing copolymer resin. Further, these reactions are carried out under a nitrogen atmosphere.

Next, to the obtained carboxyl group-containing copolymer resin, 3,4-epoxycyclohexyl methacrylate (manufactured by DAICEL Chemical Co., Ltd., trade name; Cyclomer A200) 363.9 g, dimethyl group as a ring-opening catalyst was added. Benzylamine 3.6 g, 1.00 g of hydroquinone monomethyl ether as a polymerization inhibitor, and heated to 100 ° C, this was subjected to a ring-opening addition reaction of an epoxy by stirring. After 16 hours, a solution of a carboxyl group-containing resin having an aromatic acid ring having an acid value of 108.9 mgKOH/g and a weight average molecular weight of 25,000 and containing 53.8 mass% (nonvolatile matter) was obtained. Hereinafter, the reaction solution is referred to as A-1 varnish.

Synthesis Example 2

In a flask equipped with a thermometer, a stirrer, a dropping funnel, and a reflux condenser, diethylene glycol monoethyl ether acetate as a solvent and azobisisobutyronitrile as a catalyst were placed under a nitrogen atmosphere. This was heated to 80 ° C, and the monomeric mixture of methacrylic acid and methyl methacrylate mixed at a molar ratio of 0.40:0.60 was dropped for about 2 hours. After further stirring this for 1 hour, the temperature was raised to 115 ° C to deactivate the resin solution.

After cooling the resin solution, the tetrabutylammonium bromide was used as a catalyst, and the butylepoxypropyl ether was allowed to have a molar ratio of 0.40 at 95 to 105 ° C for 30 hours. The carboxyl group of the obtained resin was subjected to an addition reaction in an equivalent amount and cooled.

Further, the OH group of the resin obtained above was subjected to an addition reaction of anhydrous tetrahydrophthalic acid at a molar ratio of 0.26 at a temperature of from 95 to 105 ° C for 8 hours. This was taken out after cooling, and a solution of a carboxyl group-containing resin having a solid content of 78.1 mgKOH/g and a weight average molecular weight of 35,000 and containing 50% by mass (nonvolatile matter) without an aromatic ring was obtained. Hereinafter, the reaction solution is referred to as A-2 varnish.

Synthesis of a carboxyl group-containing resin having an aromatic ring

Comparative Synthesis Example 1

In a flask equipped with a thermometer, a stirrer, a dropping funnel, and a reflux condenser, 210 g of a cresol novolac type epoxy resin (EPICLON N-680, epoxide equivalent = 210, manufactured by DIC Corporation) and a card as a solvent were placed. 96.4 g of the alcoholic acetate was dissolved and dissolved by heating. Next, 0.1 g of hydroquinone as a polymerization inhibiting agent and 2.0 g of triphenylphosphine as a reaction catalyst were added thereto. The mixture was heated to 95 to 105 ° C, and 72 g of acrylic acid was slowly added dropwise thereto to carry out a reaction for about 16 hours so that the acid value was 3.0 mgKOH/g or less. After cooling the reaction product to 80 to 90 ° C, 76.1 g of tetrahydrophthalic anhydride was added, and the reaction was carried out for 6 hours by infrared absorption analysis to eliminate the absorption peak of the acid anhydride (1780 cm ^-1 ). . To the reaction solution, 96.4 g of an aromatic solvent IPZOLE #150 manufactured by Idemitsu Kogyo Co., Ltd. was added, and it was taken out after dilution. The carboxyl group-containing photosensitive polymer solution thus obtained had a nonvolatile content of 65% by weight and an acid value of 78 mgKOH/g of the solid matter. Hereinafter, the reaction solution is referred to as B-1 varnish.

The combination of Examples 1 to 5 and Comparative Examples 1 to 5: Each component was blended in accordance with Table 1, and after stirring, the mixture was dispersed in a 3-roll disperser to prepare a solder resist composition. The numbers in the table indicate parts by mass.

Photopolymerization initiator A1: bis-(2,4,6-trimethylbenzylidene)phenylphosphine oxide IRUGACURE 819 (manufactured by Ciba Japan Co., Ltd.)

Photopolymerization initiator A2: 2,4,6-trimethylbenzimidyldiphenylphosphine oxide DAROCURE TPO (manufactured by Ciba Japan Co., Ltd.)

Photopolymerization initiator B1: IRUGACURE 907 (manufactured by Ciba Japan Co., Ltd.)

Photopolymerizable monomer: dipentaerythritol hexaacrylate

Titanium oxide A: Rutile type titanium oxide CR-95 (made by Ishihara Sangyo Co., Ltd.)

Titanium oxide B: anatase type titanium oxide A-220 (manufactured by Ishihara Sangyo Co., Ltd.)

Epoxy compound: TEPIC-H (manufactured by Nissan Chemical Co., Ltd.)

Thermal hardening accelerator: dicyandiamide

Sensitizer: 2,4-diethylthioxanthone KAYACURE DETX-S (manufactured by Nippon Kayaku Co., Ltd.)

Solvent: carbitol acetate

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

In order to investigate the properties of the solder resist formed by using each solder resist composition, the following tests and evaluations were carried out.

(1) Resolution (section shape)

Each of the solder resist compositions was sized to have a thickness of 100 mm × 150 mm, and a FR-4 copper-clad laminate having a thickness of 1.6 mm was screen-printed using a 100-mesh polyester (made by Baiyass). Comprehensive) printing. This was placed at 80 ° C for 10 minutes and dried in a hot air circulating drying oven. Further, on the individual dried coating films, the solder resist composition was overlaid and printed in the same manner, placed at 80 ° C for 20 minutes, and dried in a hot air circulating drying oven. Further, an exposure machine HMW-680GW (manufactured by ORC Co., Ltd.) for a printed wiring board was used, and a mask pattern having a line width of a size of 250 μm was used, and in Examples 1, 2 and 5, and Comparative Examples 1 to 3, 5 cumulative light quantity of 450mJ / cm ^2, and 3 and Example 4, Comparative Example 4 integrated light quantity places 900mJ / cm ² so that the adhesion of the solder mask with an anti-drying method of ultraviolet exposure. Thereafter, a 1% sodium carbonate aqueous solution was used as a developing solution at 30 ° C, and these were placed on a printed wiring board with a developing machine for 60 seconds. Then, these were placed at 150 ° C for 60 minutes, and subjected to heat hardening in a hot air circulating drying oven to prepare test pieces. Regarding the line width of the test piece, the cross-sectional shape of the test piece was measured by a microscope, the upper surface in contact with the photomask, and the surface of the substrate connected to the substrate. Next, the film thickness was also measured on the surface roughness of each test piece. Further, each test piece was observed and the shape was visually determined. In this determination, the shape of the cross section is almost quadrangular, and the protrusion or undercut is large and the reverse trapezoid is ×. The results are shown in Table 2. The unit is μm.

As is clear from Table 2, in the examples 1 to 5 and the comparative examples, a bis-indenylphosphine oxide-based photopolymerization initiator (B) and a monofluorenylphosphine oxide-based photopolymerization initiator (C) were used in combination. The wide cross-sectional shape has a small difference between the upper surface and the substrate surface, and the cross-sectional shape is almost quadrangular, and excellent resolution can be obtained.

(2) Light resistance, heat resistance, discoloration

The solder resist compositions of Examples 1 to 5 and Comparative Examples 1 and 5 which were excellent in the resolution test were screen-printed with a thickness of 100 mm × 150 mm on a FR-4 copper-clad laminate having a thickness of 1.6 mm. The method uses a 100 mesh polyester (made by Bayesian) to make a pattern having a film thickness of 40 μm over the entire surface (substrate). Then, the mixture was placed at 80 ° C for 30 minutes, and dried in a hot air circulating drying oven. Further, the printed wiring board was exposed to an exposure machine HMW-680GW (manufactured by ORC Co., Ltd.), and subjected to ultraviolet light exposure at a cumulative light amount of 900 mJ/cm ^{2 to} leave a negative pattern of 30 mm square. Thereafter, a 1% sodium carbonate aqueous solution was used as a developing solution at 30 ° C, and these were visualized by a developing machine for a printed wiring board for 60 seconds, and then placed at 150 ° C for 60 minutes to be thermally hardened in a hot air circulating drying oven. , each test piece for the characteristic test was produced.

The obtained test piece was measured by a color difference meter CR-400 (manufactured by KONICA MINOLTA SENSING Co., Ltd.). For each test piece, a conveyor belt type UV irradiation machine QRM-2082-E-01 (manufactured by ORC Manufacturing Co., Ltd.) was used, with a metal halide lamp, a cold mirror, a 120 W/cm ² × 3 lamp, and a conveyor belt speed of 3 m/min. The conditions of (the cumulative light amount near the wavelength of 350 nm is 3000 mJ/cm ² ) were repeated for 50 times. (Calculation, the cumulative light amount was 150 J/cm ² ), and the color difference was measured for each test piece after UV irradiation under the same conditions as the initial value, and the deterioration state was evaluated.

Next, each test piece after the light resistance test was heated in a conveyor belt type heating furnace for component mounting twice. The color difference was measured for each of the test pieces after heating under the same conditions as the initial values, and the deterioration state of each test piece was evaluated. Further, each test piece was visually evaluated. The respective results are shown in Table 3. Further, the temperature of the above heating furnace is shown in Fig. 1.

In Table 3, Y represents the reflectance of the XYZ color system, and L ^* shows the brightness of the L ^* a ^* b ^* color system. ΔE*ab is the value of each of L*a*b*, taking the square of the difference between the value after the deterioration test and the initial value, and calculating the square root of the sum. a ^* indicates the direction of red, -a ^* indicates the direction of green, b ^* indicates the direction of yellow, and -b ^* indicates the direction of blue. To approach zero means no more chroma. △E*ab indicates a change in color, and the smaller the value, the smaller the change in color.

In Examples 1 to 5, after the light resistance test, and after the heating test, the value of ΔE*ab and the visual evaluation were obtained, and good results were obtained in which the discoloration was small.

(3) Solder heat resistance

In each of Examples 1 to 5, each of the produced products was produced in the same manner as in (2). On the test piece, after applying a rosin-based flux, it was flow-washed in a solder bath at 260 ° C for 10 seconds. Thereafter, these were washed with propylene glycol monomethyl ether acetate and dried, and then subjected to a peeling test by a cellophane adhesive tape to evaluate the peeling of the coating film. In this evaluation, the one without peeling was ○, and the one without peeling was ×. The results are shown in Table 4.

(4) Solvent resistance

In each of Examples 1 to 5, 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 applied to a cellophane adhesive tape. The peeling test was performed to evaluate the peeling of the coating film. In this evaluation, the one without peeling was ○, and the one without peeling was ×. The results are shown in Table 4.

(5) Pencil hardness test

In each of the test pieces prepared in the same manner as in (2), the pencils of the B to 9H which had been flattened by the tip of the refill were pressed at an angle of about 45° in the examples 1 to 5, and recorded. The pencil hardness of the peeling of the coating film does not occur. The results are shown in Table 4.

(6) Insulation resistance test

In the examples 1 to 5, except for the FR-4 copper-clad laminate, which was replaced with the gate electrode B test plate of the IPC B-25 test pattern, the test pieces were prepared under the same conditions as in (2). . On these test pieces, a bias voltage of DC500V was applied to measure the insulation resistance value. If the value is 100 GΩ or more, it is ○, and if it is less than 100 GΩ, it is ×. The results are shown in Table 4.

As is apparent from Table 4, in Examples 1 to 5 using the solder resist composition of the present invention, it has excellent heat resistance, solvent resistance, adhesion, and electrical insulating properties required for the solder resist.

As described in detail above, it is known that the solder resist composition of the present invention is excellent in resolution even when it is blended with titanium oxide. Further, the solder resist formed by using the solder resist composition of the present invention has less discoloration due to light or heat, and is excellent in high reflectance.

[Fig. 1] The graph shows the light resistance of the test pieces used in the examples and comparative examples. The temperature of the heating furnace for the heat discoloration test.

Claims (10)

A solder resist composition characterized by (A) a carboxyl group-containing resin having no aromatic ring, (B) a bis-indenylphosphine oxide-based photopolymerization initiator, and (C) a mono-fluorenylphosphine oxide-based photopolymerization a starting agent, (D) a photopolymerizable monomer, (E) a rutile type titanium oxide, and (G) an organic solvent, and the (B) bis-indenyl phosphine oxide-based photopolymerization initiator and the foregoing ( C) The ratio of the monothiol phosphine-based photopolymerization initiator is from 90:10 to 1:99. The solder resist composition according to claim 1, wherein the carboxyl group-containing resin (A) having no aromatic ring is (a) a carboxyl group-containing (meth)acrylic copolymer resin and (b) 1 A copolymer resin having a carboxyl group obtained by a reaction of a compound having an epoxy group and an ethylenically unsaturated group in the molecule. The solder resist composition according to claim 1, which further contains (F) an epoxy compound. The solder resist composition according to claim 2, which further contains (F) an epoxy compound. The solder resist composition according to any one of claims 1 to 4, further comprising (H) a thioxanthone photopolymerization sensitizer. A printed wiring board comprising a printed wiring board having a base material on which a cured material of a solder resist composition is formed, characterized in that the cured product contains (A) a carboxyl group-containing resin having no aromatic ring, and (B) a double enthalpy a phosphine oxide-based photopolymerization initiator, (C) a monodecylphosphine oxide-based photopolymerization initiator, (D) a photopolymerizable monomer and (E) rutile type titanium oxide, and the (B) bis-indenyl phosphine oxide-based photopolymerization initiator and the (C) monodecylphosphine oxide-based light The mixing ratio of the polymerization initiator is 90:10~1:99. The printed wiring board according to claim 6, wherein the carboxyl group-containing resin (A) having no aromatic ring is composed of (a) a carboxyl group-containing (meth)acrylic copolymer resin and (b) one molecule. A copolymer resin having a carboxyl group obtained by a reaction of a compound having an epoxy group and an ethylenically unsaturated group. The printed wiring board according to claim 6, wherein the cured product further contains (F) an epoxy compound. The printed wiring board according to claim 6, further comprising (H) a thioxanthone photopolymerization sensitizer. The printed wiring board according to any one of claims 6 to 9, wherein the printed wiring board substrate is provided with a light-emitting diode.