JP2008019336A - Photocurable and thermosetting one-pack type solder resist composition and printed wiring board using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an alkali developable photocurable and thermosetting one-pack type solder resist composition having excellent coating film properties of heat resistance, adhesivity, electroless gold plating resistance and electric properties and excellent dry tack and workability and a printed wiring board using the same. <P>SOLUTION: The one-pack type solder resist composition comprises (A) a carboxy group-containing photosensitive resin which is obtained by adding a compound (c) containing both a cyclic ether group and an ethylenic unsaturated group in one molecule to a copolymer composed of an unsaturated carboxylic acid (a) and a compound (b) containing an ethylenic unsaturated group except the unsaturated carboxylic acid and has a softening point of 130-200°C, (B) a diluent, (C) a photopolymerization initiator, (D) a melamine or its organic acid salt and (E) an inorganic filler. The printed wiring board is obtained by using the composition. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a photocurable / thermosetting one-component solder resist composition useful for the production of printed wiring boards and a printed wiring board using the same, and more particularly, heat resistance , Photocurable / thermosetting one-component solder resist composition with excellent adhesiveness, electroless gold plating resistance, electrical coating properties, dry touch, and workability The present invention relates to a printed wiring board using the above.

  Currently, the solder resist used in the production of printed wiring boards is a liquid alkaline development type solder resist that forms an image by developing after exposure and heat-cures to form a coating film from the viewpoint of high accuracy and high density. Is used. As an alkali development type solder resist using such a dilute alkaline aqueous solution, for example, an active energy obtained by adding a saturated or unsaturated polybasic acid anhydride to a reaction product of a novolak type epoxy compound and an unsaturated monocarboxylic acid. A two-component liquid solder resist composition composed of a linear curable resin, a photopolymerization initiator, a diluent, and an epoxy compound has been proposed (see, for example, Patent Document 1).

  However, most of these liquid alkali development type solder resists are active energy ray-curable resins obtained by adding a polybasic acid anhydride to the reaction product of a novolak epoxy compound and an unsaturated monocarboxylic acid, and photopolymerization is initiated. It is a two-pack type solder resist composed of a main agent composed of an agent and a curing agent composed of a diluent, an epoxy compound, etc., and must be used after thoroughly mixing the main agent and the curing agent. Further, the pot life after mixing is as short as 24 hours or less, and further, the carboxyl group contained in the active energy ray-curable resin as the main agent and the epoxy group of the epoxy compound in the curing agent are gradually added between the drying step and the developing step. There is a problem in work, such as causing poor development (hot fogging).

  For such a problem, for example, at least one free carboxyl group in one molecule, or at least one photoreactive unsaturated group at room temperature, a solid polymer compound or A one-component solder resist containing an oligomer, a diluent, a photopolymerization initiator, melamine or a derivative thereof, or 2,4,6-trismercapto-S-triazine has been proposed (see, for example, Patent Document 2). However, although this one-pack type solder resist is excellent in workability, the heat resistance and electroless gold plating resistance are unstable as compared with the two-pack type liquid solder resist and have not yet been put into practical use.

In addition, such an alkali development type solder resist is required to have high sensitivity and finger touchability compatible with an automatic exposure machine in order to improve productivity. Generally, in order to increase the sensitivity, it is necessary to increase the amount of low-molecular weight photopolymerizable monomer. However, if such a low molecular weight photopolymerizable monomer is increased, the dryness to touch is significantly reduced. There was a problem to do.
Japanese Patent Publication No. 1-54390 (Claims) JP-A-8-335768 (Claims)

  Therefore, the present invention has been made to solve the above-described problems of the prior art, and its main purpose is to have storage stability that can be used as a one-part composition and to be sufficiently satisfactory as a solder resist. One of the photocuring and thermosetting properties that can be developed with alkali that has heat resistance, adhesion, electroless gold plating resistance, electrical characteristics and other coating properties, excellent dryness to touch, and high sensitivity. It is an object to provide a liquid solder resist composition, a dry film using the same, and a printed wiring board.

As a result of intensive studies to achieve the above object, the first aspect of the present invention is that (A) an unsaturated carboxylic acid (a) and an ethylenically unsaturated group in one molecule other than the unsaturated carboxylic acid. It is obtained by adding a compound (c) having both a cyclic ether group and an ethylenically unsaturated fatty group in one molecule to a copolymer comprising a compound (b) having a softening point of 130 to 200 ° C. A certain carboxyl group-containing photosensitive resin,
(B) Diluent,
(C) a photopolymerization initiator,
(D) melamine or an organic acid salt thereof,
And (E) a photocurable / thermosetting one-component solder resist composition capable of alkali development, comprising an inorganic filler.
As another form of provision, there is provided a photocurable / thermosetting dry film obtained by applying the solder resist composition to a carrier film and drying.
Furthermore, a printed wiring board is provided in which a solder resist layer is formed on the surface of a printed wiring board on which a circuit is formed using a one-pack type solder resist composition or a dry film.

The photocurable / thermosetting solder resist composition capable of alkali development of the present invention has storage stability that can be used as a one-part composition, and has a long drying control width after being applied to a printed wiring board and dried. Furthermore, since it has coating properties such as heat resistance, adhesion, electroless gold plating resistance, and electrical properties that can be satisfactorily satisfied as a solder resist, it is also possible to provide highly reliable printed wiring boards at a low price. . In addition, since it has such storage stability, it is excellent in storage stability as a dry film, eliminates the need for low-temperature storage, and enables cost reduction.
Furthermore, since it is excellent in dryness to touch, it can be applied to an automatic exposure machine. Since it has such a touch-drying property, it is possible to increase the amount of the photopolymerizable monomer, so that it is easy to increase the sensitivity.

The basic aspect of the alkali-developable photocurable / thermosetting one-component solder resist composition of the present invention is (A) an unsaturated carboxylic acid (a) and a molecule other than the unsaturated carboxylic acid. It is obtained by adding a compound (c) having both a cyclic ether group and an ethylenically unsaturated fatty group in one molecule to a copolymer comprising the compound (b) having an ethylenically unsaturated group, and has a softening point. A carboxyl group-containing photosensitive resin having a temperature of 130 to 200 ° C .;
(B) Diluent,
(C) a photopolymerization initiator,
(D) melamine or an organic acid salt thereof,
And (E) a solder resist composition containing an inorganic filler has storage stability that can be used as a one-part composition, and is satisfactory as a solder resist, heat resistance, adhesion, electroless gold plating resistance, electrical properties It has been found that the coating film characteristics are excellent and the dryness to touch is excellent, and the present invention has been completed.

That is, the alkali-developable photocurable / thermosetting one-component solder resist composition of the present invention is characterized in that the first feature is in the unsaturated carboxylic acid (a) and one molecule other than the unsaturated carboxylic acid. Obtained by adding a compound (c) having both a cyclic ether group and an ethylenically unsaturated fatty group in one molecule to a copolymer comprising the compound (b) having an ethylenically unsaturated group at the same time, and a softening point. Is a point in which a carboxyl group-containing photosensitive resin having a temperature of 130 to 200 ° C. is used, and this makes it possible to obtain a coating film excellent in dryness to touch and excellent in film forming property. Furthermore, in the one-component solder resist composition of the present invention, melamine or an organic acid salt thereof is used in combination with the carboxyl group-containing photosensitive resin instead of a thermosetting component such as an epoxy resin used in conventional products. As a result, it was found that the heat resistance and electroless gold plating resistance were remarkably improved, and the one-pack type solder resist composition of the present invention was completed.
Such a melamine or an organic acid salt thereof has a molecular chain in which the ethylenically unsaturated group of the carboxyl group-containing photosensitive resin (A) and the active hydrogen of the melamine or the organic acid salt thereof partially undergo an addition reaction during heat curing. It is considered that the adhesion between the coating film and the copper foil is improved by the chelating effect and the antirust effect on the copper foil.
In this specification, the softening point is determined from the amount of change in the position of the needle-inserted probe with a temperature of 5 ° C./min and a load of 1 g using a thermomechanical analyzer (TMA). Asked.
(However, in consideration of an increase in the softening point due to thermal polymerization, the measurement resin was measured by adding about 1,000 ppm of a thermal polymerization inhibitor.)

Hereinafter, each component of the photocurable / thermosetting one-component solder resist composition of the present invention will be described in detail.
First, the carboxyl group-containing photosensitive resin (A) used in the present invention includes an unsaturated carboxylic acid (a) and a compound (b) having an ethylenically unsaturated group in one molecule other than the unsaturated carboxylic acid. It is a resin obtained by adding a compound (c) having both a cyclic ether group and an ethylenically unsaturated fatty group in one molecule to a copolymer comprising the above, and having a softening point of 130 to 200 ° C.
The softening point of the carboxyl group-containing photosensitive resin (A) is 130 to 200 ° C, preferably 135 to 180 ° C, and more preferably 140 to 180 ° C. When the softening point is lower than the above range, it is not preferable because sufficient dryness to the touch cannot be obtained. On the other hand, when the softening point is higher than the above range, alkali developability is lowered, which is not preferable.
In the case of a resin having a softening point exceeding 200 ° C., for example, a resin in which glycidyl methacrylate is added to a copolymer resin of N-phenylmaleimide and methacrylic acid, the above thermomechanical analyzer increases the softening point due to thermal polymerization. Since an accurate value cannot be measured, the softening point was estimated with a resin to which butyl glycidyl ether having no polymerizable property was added. (These were not developable.)

Such a carboxyl group-containing photosensitive resin (A) has a weight average molecular weight of 8,000 to 70,000, more preferably 10,000 to 50,000. When the weight average molecular weight is less than 8,000, sufficient film forming property cannot be obtained, which is not preferable. On the other hand, when the weight average molecular weight exceeds 70,000, the solubility of the carboxyl group-containing photosensitive resin in an organic solvent is lowered or the developability is lowered.
Moreover, the acid value of the said carboxyl group-containing photosensitive resin (A) is 30-150 mgKOH / g, More preferably, the acid value is 50-140 mgKOH / g. When the acid value is less than 30 mgKOH / g, the solubility in an alkaline aqueous solution is deteriorated and development is difficult, which is not preferable. On the other hand, when the acid value exceeds 150 mgKOH / g, the development resistance is lowered, which is not preferable.

As unsaturated carboxylic acid (a) used for the synthesis | combination of the said carboxyl group-containing photosensitive resin (A), unsaturated monocarboxylic acid, such as acrylic acid, methacrylic acid, (beta) -carboxylethyl (meth) acrylate, and maleic acid , Unsaturated dibasic acids such as fumaric acid, itaconic acid, citraconic acid, and hydroxyl group-containing (such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate) There are adducts of (meth) acrylate and dibasic acid anhydride. Examples of the dibasic acid anhydride include phthalic anhydride, methyltetrahydrophthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, succinic anhydride, maleic anhydride, itaconic anhydride, and nadic anhydride. An acid etc. are mentioned. Among these, acrylic acid or methacrylic acid is particularly preferable from the viewpoint of photosensitivity and storage stability. These unsaturated carboxylic acids (a) may be used alone or in admixture of two or more.
In this specification, (meth) acrylate is a general term for acrylate and methacrylate, and the same applies to other similar expressions.

  As the compound (b) having an ethylenically unsaturated group in one molecule other than the unsaturated carboxylic acid used for the synthesis of the carboxyl group-containing photosensitive resin (A) of the present invention, styrene, α-methylstyrene, vinyl acetate, Vinyl compounds such as vinyl benzoate; methyl (meth) acrylate, ethyl (meth) acrylate, lauryl (meth) acrylate, isopropyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl ( (Meth) acrylate, isobornyl (meth) acrylate, benzyl (meth) acrylate, phenyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, phenyl (Meth) acrylic acid esters such as glycidyl ether (meth) acrylate.

  As the compound (c) having both a cyclic ether group and an ethylenically unsaturated fatty group in one molecule used for the synthesis of the carboxyl group-containing photosensitive resin (A) of the present invention, glycidyl (meth) acrylate, methyl glycidyl (meth) Acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 3,4-epoxycyclohexylethyl (meth) acrylate, 3,4-epoxycyclohexylbutyl (meth) acrylate, 3,4-epoxycyclohexylmethylamino acrylate, (3 -Ethyl-3-oxetanyl) methyl (meth) acrylate, (3-methyl-3-oxetanyl) methyl (meth) acrylate, 3-oxetanylmethyl (meth) acrylate and the like. Among these, 3,4-epoxycyclohexylmethyl (meth) acrylate is particularly preferable.

The diluent (B) used in the present invention is used to adjust the viscosity of the ink composition to improve workability, and to increase the crosslink density or improve adhesion, such as a photopolymerizable monomer. The reactive diluent (B-1) or a known and commonly used organic solvent (B-2) can be used.
Examples of the reactive diluent (B-1) include alkyl (meth) acrylates such as 2-ethylhexyl (meth) acrylate and cyclohexyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) Hydroxyalkyl (meth) acrylates such as acrylate; mono- or di (meth) acrylates of alkylene oxide derivatives such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol; hexanediol, tricyclodecane dimethanol, trimethylolpropane, Polyhydric alcohols such as pentaerythritol, ditrimethylolpropane, dipentaerythritol, trishydroxyethyl isocyanurate, or their ethylene oxide or propylene Polyhydric (meth) acrylates of xoxide adducts; (meth) acrylates of ethylene oxide or propylene oxide adducts of phenols such as phenoxyethyl (meth) acrylate and polyethoxydi (meth) acrylate of bisphenol A; glycerin diglycidyl ether, And (meth) acrylates of glycidyl ethers such as trimethylolpropane triglycidyl ether and triglycidyl isocyanurate; and melamine (meth) acrylate.
These can be used alone or in combination of two or more, and (meth) acrylates containing a hydrophilic group are preferable in terms of adhesion, and polyfunctional (meth) acrylates are preferable in terms of photocurability. The blending amount of these photopolymerization monomers is preferably 20 to 120 parts by mass, more preferably 20 to 100 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin (A). If it is less than 20 parts by mass, the photoreactivity is poor, and if it is more than 120 parts by mass, the dryness to touch becomes poor, which is not preferable.

Examples of the organic solvent (B-2) include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methylcarbitol, butylcarbi Toluene, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, tripropylene glycol monomethyl ether and other glycol ethers; ethyl acetate, butyl acetate, butyl lactate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl Carbitol acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether Seteto, esters such as propylene carbonate; octane, aliphatic hydrocarbons decane; petroleum ether, petroleum naphtha, and petroleum solvents such as solvent naphtha, organic solvents conventionally known can be used. These organic solvents can be used alone or in combination of two or more.
The amount of such an organic solvent varies depending on the coating method and the boiling point of the organic solvent to be used, and is not particularly limited. However, when a high-boiling organic solvent is contained in a large amount, the dryness to touch decreases. Or sagging after the coating and before temporary drying.

  Examples of the photopolymerization initiator (C) used in the present invention include benzoin and benzoin alkyl ethers such as benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether; acetophenone, 2,2-dimethoxy-2-phenyl Acetophenones such as acetophenone, 2,2-diethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone; 2-methyl-1- [4- (methylthio) phenyl]- Aminoacetophenones such as 2-morpholinopropan-1-one and 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1; 2-methylanthraquinone, 2-ethylanthraquinone, 2- Tertiary Anthraquinones such as tilanthraquinone and 1-chloroanthraquinone; Thioxanthones such as 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone and 2,4-diisopropylthioxanthone; Acetophenone dimethyl ketal, benzyldimethyl ketal, etc. Benzophenones such as benzophenone; or xanthones; (2,6-dimethoxybenzoyl) -2,4,4-pentylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, Phosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide and ethyl-2,4,6-trimethylbenzoylphenylphosphinate; various peroxides And N, N-dimethylaminobenzoic acid ethyl ester, N, N-dimethylaminobenzoic acid isoamyl ester, pentyl-4-dimethylaminobenzoate, triethylamine, triethanolamine, and the like. You may use together with photosensitizers, such as tertiary amines, such as. These photopolymerization initiators can be used alone or in combination of two or more. Moreover, the compounding quantity of these photoinitiators (C) is 1-25 mass parts with respect to 100 mass parts of carboxyl group-containing photosensitive resin (A), More preferably, it is 2-20 mass parts. When the amount is less than 1 part by mass, the photocurability is lowered, and pattern formation after exposure / development becomes difficult. On the other hand, when the amount exceeds 25 parts by mass, the thick film curability is lowered and the cost is increased.

  As melamine or its organic acid salt (D), melamine or a product obtained by reacting melamine with an equimolar amount of organic acid can be used. The organic acid salt of melamine can be obtained by dissolving melamine in boiling water, adding an organic acid dissolved in water or a hydrophilic solvent such as alcohol, and filtering the deposited salt. One amino group in the melamine molecule is fast reactive but the other two are low in reactivity, so the reaction proceeds stoichiometrically, and an organic acid is attached to one amino group in the melamine molecule. One added melamine salt is formed. Examples of the organic acid include a carboxyl group-containing compound, an acidic phosphate ester compound, and a sulfonic acid-containing compound, and any of them can be used, but a carboxyl group-containing compound is more preferable.

Examples of the carboxyl group-containing compound include formic acid, acetic acid, propionic acid, butyric acid, lactic acid, glycolic acid, acrylic acid, and methacrylic acid as monocarboxylic acids, and oxalic acid, malonic acid, and succinic acid as dicarboxylic acids. , Glutaric acid, adipic acid, sebacic acid, maleic acid, itaconic acid, phthalic acid, hexahydrophthalic acid, 3-methylhexahydrophthalic acid, 4-methylhexahydrophthalic acid, 3-ethylhexahydrophthalic acid, 4- There are ethylhexahydrophthalic acid, tetrahydrophthalic acid, 3-methyltetrahydrophthalic acid, 4-methyltetrahydrophthalic acid, 3-ethyltetrahydrophthalic acid, 4-ethyltetrahydrophthalic acid, and crotonic acid. There are merit acids. Among these, a salt obtained by an equimolar reaction of dicarboxylic acid and melamine is particularly preferable because there is little deterioration in the properties of the solder resist to which it is added. Polybasic acid anhydrides can also be used. In general, polybasic acid anhydrides are easily opened by, for example, dissolving in boiling water to produce the corresponding polycarboxylic acids.
The blending amount of these melamines or organic acid salts (D) thereof is desirably 1 to 25 parts by mass, more preferably 2 to 20 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin (A). . When the blending amount is less than 1 part by mass, the adhesion and heat resistance are lowered, and when it exceeds 25 parts by mass, the photoreactivity is lowered. In addition, when using the organic acid salt of melamine, about 1.5 to 2 times the case of using melamine is necessary.

  Known inorganic fillers (E) such as barium sulfate, barium titanate, silicon oxide powder, finely divided silicon oxide, amorphous silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, mica, etc. These inorganic fillers can be used alone or in combination of two or more. These are used for the purpose of suppressing curing shrinkage of the coating film and improving properties such as adhesion and hardness. The blending amount is desirably 50 to 250 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin (A). When the amount is less than the above range, adhesion and heat resistance are reduced. On the other hand, when the amount is more than the above range, the coating strength is lowered and the sensitivity is lowered.

Furthermore, if necessary, known and commonly used coloring pigments, coloring dyes, thermal polymerization inhibitors, thickeners, antifoaming agents, leveling agents, coupling agents, flame retardant aids and the like can be used.
In addition, the one-component solder resist composition of the present invention has a phenol novolac type epoxy resin, a cresol novolac type epoxy resin, a bisphenol type epoxy resin, a biphenyl type epoxy resin, and a triglycidyl isocyanate within a range that does not adversely affect storage stability. Known and commonly used epoxy resins such as nurate can be used. In particular, adhesion and the like can be improved by adding a small amount of a poorly soluble epoxy resin to an organic solvent such as a bixylenol type epoxy resin or triglycidyl isocyanurate.

  The one-component solder resist composition of the present invention can be provided in the form of a liquid, a paste or a dry film. When supplying as a dry film, for example, after applying the solder resist composition of the present invention on a carrier film by a roll coater, a doctor bar, a wire bar method, a spin coating method, a doctor plate method, etc., the temperature is set to 60 to 100 ° C. It can be obtained by drying in a drying oven to remove the organic solvent and, if necessary, attaching a release film. At this time, the thickness of the resist on the carrier film is adjusted to 5 to 150 μm, preferably 10 to 60 μm. As the carrier film, a film of polyethylene terephthalate, polypropylene or the like is preferably used.

  The one-component solder resist composition of the present invention having the above composition is diluted as necessary to adjust the viscosity to be suitable for the coating method, and this is screen-printed, for example, on a printed wiring board on which a circuit is formed. A tack-free coating film is formed by applying the organic solvent contained in the composition at a temperature of 70 to 90 ° C. it can. Then, it can be exposed selectively with active energy rays through a photomask, and the unexposed part can be developed with a dilute alkaline aqueous solution to form a resist pattern. Furthermore, by heat curing, heat resistance, adhesion, electroless gold plating A printed circuit board having a solder resist film having excellent resistance, electrical characteristics and the like is formed.

  As the dilute alkaline aqueous solution, alkaline aqueous solutions such as potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, amines and the like can be used. As an irradiation light source for exposure, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a xenon lamp, a metal halide lamp, or the like can be used. In addition, a laser beam can also be used as an actinic beam.

  EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the following description, “part” means “part by mass” unless otherwise specified.

Synthesis example 1
In a flask equipped with a thermometer, stirrer, dropping funnel, and reflux condenser, 700.0 g of dipropylene glycol monomethyl ether as a solvent is heated to 110 ° C., and 270.0 g of methacrylic acid, 153.0 g of methyl methacrylate, A mixture of 294.0 g of propylene glycol monomethyl ether and 10.0 g of t-butylperoxy-2-ethylhexanoate (Nippon Yushi Co., Ltd., Perbutyl O) as a polymerization catalyst was added dropwise over 3 hours. The polymerization catalyst was deactivated by stirring for a time to obtain a copolymer resin solution. After cooling this resin solution, 390.0 g of 3,4-epoxycyclohexylmethyl acrylate (Daicel Chemical Industries, Ltd. Cyclomer A400), 5.0 g of triphenylphosphine, and 1.5 g of hydroquinone monomethyl ether were added, and the mixture was heated to 100 ° C. Epoxy ring-opening addition reaction was carried out by heating and stirring. The carboxyl group-containing photosensitive resin thus obtained had a weight average molecular weight of 22,000, a non-volatile content of 45 wt%, and a solid content acid value of 70 mg KOH / g. Hereinafter, this reaction solution is called varnish A-1.

Synthesis example 2
In a flask equipped with a thermometer, a stirrer, a dropping funnel and a reflux condenser, 500.0 g of dipropylene glycol monomethyl ether as a solvent is heated to 110 ° C., and 165.0 g of methacrylic acid, 81.6 g of methyl methacrylate, A mixture of 120.4 g of propylene glycol monomethyl ether and 6.2 g of t-butyl peroxy-2-ethylhexanoate (Nippon Yushi Co., Ltd., perbutyl O) as a polymerization catalyst was added dropwise over 3 hours. The polymerization catalyst was deactivated by stirring for a time to obtain a copolymer resin solution. After cooling the resin solution, 167.0 g of 3,4-epoxycyclohexylmethyl acrylate (Cyclomer A400 manufactured by Daicel Chemical Industries, Ltd.), 4.0 g of triphenylphosphine, and 1.0 g of hydroquinone monomethyl ether were added, and the mixture was heated to 100 ° C. Epoxy ring-opening addition reaction was carried out by heating and stirring. The carboxyl group-containing photosensitive resin thus obtained had a weight average molecular weight of 23,000, a non-volatile content of 40 wt%, and a solid acid value of 135 mg KOH / g. Hereinafter, this reaction solution is called varnish A-2.

Synthesis example 3
In a flask equipped with a thermometer, a stirrer, a dropping funnel and a reflux condenser, 200.0 g of dipropylene glycol monomethyl ether as a solvent is heated to 110 ° C., 29.6 g of β-carboxyethyl acrylate, 70.8 g of methacrylic acid. , 139.5 g of methyl methacrylate, 123.0 g of dipropylene glycol monomethyl ether, and 7.0 g of t-butyl peroxy-2-ethylhexanoate (Perbutyl O manufactured by NOF Corporation) as a polymerization catalyst over 3 hours Then, the mixture was further stirred at 110 ° C. for 3 hours to deactivate the polymerization catalyst to obtain a copolymer resin solution. After cooling this resin solution, 110.5 g of glycidyl methacrylate, 4.0 g of triphenylphosphine and 1.0 g of hydroquinone monomethyl ether were added, and the temperature was raised to 100 ° C., followed by stirring to carry out an epoxy ring-opening addition reaction. The carboxyl group-containing photosensitive resin thus obtained had a weight average molecular weight of 15,000, a nonvolatile content of 52 wt%, and a solid acid value of 40 mgKOH / g. Hereinafter, this reaction solution is called varnish A-3.

Comparative Synthesis Example 1
In a flask equipped with a thermometer, a stirrer, a dropping funnel, and a reflux condenser, 400.0 g of dipropylene glycol monomethyl ether as a solvent is heated to 110 ° C., and 172.0 g of methacrylic acid, 100.0 g of methyl methacrylate, methacrylic acid A mixture of 114.0 g of ethyl acid, 244.0 g of dipropylene glycol monomethyl ether, and 7.8 g of t-butyl peroxy-2-ethylhexanoate (Perbutyl O manufactured by NOF Corporation) was added dropwise over 3 hours as a polymerization catalyst. The mixture was further stirred at 110 ° C. for 3 hours to deactivate the polymerization catalyst to obtain a copolymer resin solution. After cooling this resin solution, 158.0 g of glycidyl methacrylate, 6.0 g of triphenylphosphine, and 1.5 g of hydroquinone monomethyl ether were added, and the mixture was heated to 100 ° C. and stirred to carry out an epoxy ring-opening addition reaction. The thus obtained carboxyl group-containing photosensitive resin had a weight average molecular weight of 29,000, a nonvolatile content of 50 wt%, and a solid acid value of 91 mgKOH / g. Hereinafter, this reaction solution is referred to as Varnish R-1.

(1) Measurement of softening point of carboxyl group-containing photosensitive resin In order to prevent thermal polymerization at the time of softening point measurement in each of the varnishes obtained in Synthesis Examples 1 to 3 and Comparative Synthesis Example 1, as a polymerization inhibitor After adding about 1,000 ppm of p-methoxyphenol (methoquinone), it was applied to a glass plate and dried at 80 ° C. for 4 hours. The softening point was measured on condition of the following conditions using TMS4000S made from a thermomechanical analyzer Bruker AXS Co., Ltd. using the coating film peeled off from the glass plate after drying as a test sample. The results are shown in Table 2.
Probe: Needle-in probe Probe Load: 1g
Temperature increase rate: 10 ° C / min
Measurement range: 30-250 ° C

Examples 1-4 and Comparative Examples 1-3
Using each varnish obtained in Synthesis Examples 1 to 3 and Comparative Synthesis Example (mixed so that the solid content is 100), each component is blended in the blending ratio shown in Table 1 below, and a three roll mill is used. And kneaded to prepare a photocurable / thermosetting one-component solder resist composition capable of alkali development. In addition, it diluted with the organic solvent as needed at the time of printing.

  About each one-pack type solder resist composition of the said Examples 1-4 and Comparative Examples 1-3, it tested about each following item and evaluated. The results of each evaluation are shown in Table 2. The evaluation test method is shown below.

(2) Storage stability After adjusting the one-component solder resist compositions of Examples 1 to 4 and Comparative Examples 1 to 3, the initial value of viscosity at 25 ° C. was measured with an EHD viscometer (5 rpm Value) and then stored in a constant temperature bath at 20 ° C. for 6 months, and the viscosity was measured in the same manner as the initial value. From the viscosity increase rate, the following criteria were used for evaluation.
○: Thickening rate is within 120%.
(Triangle | delta): Thickening rate is 120 to 200% or less.
X: Gelation or thickening rate is 200% or more.

(3) Developability Each one-component solder resist composition obtained in Examples 1 to 4 and Comparative Examples 1 to 3 was applied on the entire surface of a copper-clad substrate by screen printing, and then heated in a hot air circulation drying oven. The film was dried at 90 ° C. for 60 minutes, developed with a 1 wt% Na ₂ CO ₃ aqueous solution with a spray pressure of 0.2 MPa for 1 minute, and the developability of the coating film surface was evaluated according to the following criteria.
○: The coating film is completely removed and there is no residue.
Δ: Slightly filler remaining,
X: Residual film residue

(4) Sensitivity The one-pack type solder resist compositions obtained in Examples 1 to 4 and Comparative Examples 1 to 3 were each applied to the entire surface of a glass epoxy substrate by screen printing, and then heated at 80 ° C. in a hot air circulation drying oven. Dry for 30 minutes. On these substrates, Kodak No. 2 step tablets were applied, exposed at 200 mJ / cm ² , developed with a 1 wt% Na ₂ CO ₃ aqueous solution with a spray pressure of 0.2 MPa for 1 minute, and the number of steps where the coating film remained completely was evaluated.

(5) Tackiness The one-pack type solder resist compositions obtained in Examples 1 to 4 and Comparative Examples 1 to 3 were each applied to the printed circuit board on which the circuit was formed by screen printing, respectively, and a hot-air circulating drying oven And dried at 80 ° C. for 30 minutes. A negative pattern was applied to the evaluation substrate, and contact exposure was performed under vacuum. Then, it returned to normal pressure and evaluated the adhesiveness at the time of peeling a negative pattern on the following references | standards.
○: No sticking.
Δ: Slightly attached.
X: There is sticking.

(6) Solder heat resistance The one-pack type solder resist compositions obtained in Examples 1 to 7 and Comparative Examples 1 to 4 were each applied to the printed circuit board on which the circuit was formed by screen printing. It was dried at 80 ° C. for 30 minutes in a drying furnace. A negative film on which a solder resist pattern is drawn is applied to these substrates, exposed under an exposure condition of an exposure amount of 300 mJ / cm ² , and developed with a 1 wt% Na ₂ CO ₃ aqueous solution with a spray pressure of 0.2 MPa for 1 minute. A pattern was formed. This substrate was thermally cured at 150 ° C. for 60 minutes to produce an evaluation substrate.
A rosin-based flux is applied to this evaluation substrate, immersed in a solder bath set at 260 ° C. in advance for 30 seconds, the flux is washed with isopropyl alcohol, a peel test is performed with a cellophane adhesive tape, and the resist layer is swollen. The peeling and discoloration were evaluated according to the following criteria.
○: No change at all △: Slight change in color, etc. ×: Resist layer swelling or peeling

(7) Resistance to electroless gold plating An evaluation substrate was prepared in the same manner as in (6) above. This evaluation substrate was subjected to electroless gold plating using commercially available electroless nickel plating solution and electroless gold plating solution under the conditions of nickel 5 μm and gold 0.03 μm. About the evaluation board | substrate after this plating, the peel test by a cellophane adhesive tape was performed, and the following references | standards evaluated the peeling of the resist layer and the penetration of plating.
○: No change at all △: Slightly peeled off, with smudges ×: Painted film with peeling

(8) Electrical Insulation An evaluation board was prepared under the same conditions as in (6) above using a comb-type electrode B coupon with an IPC B-25 test pattern, and a bias voltage of DC 100 V was applied to the comb-type electrode, and 85 ° C, 85% R.V. H. The insulation resistance value after 1,000 hours was measured in a constant temperature and humidity chamber.

As is apparent from the results shown in Table 2, the one-component solder resist compositions of Examples 1 to 4 according to the present invention are excellent in storage stability, high in sensitivity, and excellent in tackiness. Moreover, the solder heat resistance, the electroless gold plating resistance, and the electrical insulation necessary for the solder resist have satisfactory characteristics.
On the other hand, Comparative Example 1 in which the softening point of the carboxyl group-containing photosensitive resin is 95 ° C. is inferior in tackiness. In addition, in Comparative Example 2 in which the reactive diluent was reduced in order to improve the tackiness, the sensitivity was greatly lowered.
Moreover, like the conventional two-component solder resist, Comparative Example 3 in which about 1.1 equivalent of epoxy resin is blended with 1 equivalent of carboxyl group is excellent in heat resistance, etc. The storage stability as a type solder resist composition was remarkably inferior.

Claims (5)

(A) a copolymer comprising an unsaturated carboxylic acid (a) and a compound (b) having an ethylenically unsaturated group in one molecule other than the unsaturated carboxylic acid, a cyclic ether group in one molecule; A carboxyl group-containing photosensitive resin obtained by adding the compound (c) having an ethylenically unsaturated fatty group and having a softening point of 130 to 200 ° C.,
(B) Diluent,
(C) a photopolymerization initiator,
(D) melamine or an organic acid salt thereof,
And (E) a photocurable / thermosetting one-component solder resist composition capable of alkali development, comprising an inorganic filler. The one-component solder resist composition according to claim 1, wherein the copolymer resin (A) has a weight average molecular weight of 8,000 to 70,000. 3. The compound according to claim 1, wherein the compound (c) having both a cyclic ether group and an ethylenically unsaturated fatty group in one molecule is 3,4-epoxycyclohexylmethyl (meth) acrylate. Liquid solder resist composition. A photocurable / thermosetting dry film obtained by applying and drying the one-component solder resist composition according to any one of claims 1 to 3 on a carrier film. A solder resist layer is formed on the surface of the printed wiring board formed with a circuit using the one-component solder resist composition according to any one of claims 1 to 3 or the dry film according to claim 4. Printed wiring board characterized by being made.