JPH0876379A - Photosetting and thermosetting resin composition - Google Patents

Abstract

PURPOSE: To obtain a photosetting and thermosetting resin compsn. developable with a dil. aq. alkali soln., giving a film excellent in various characteristics such as wear resistance, slidability, electric insulating property and hardness and useful to form the soldering resist film of a printed circuit board and the insulating resin layers of various electronic parts. CONSTITUTION: This photosetting and thermosetting resin compsn. contains a resin (A) curable with active energy beams and having at least two ethylenically unsatd. bonds and a carboxyl group in one molecule, a high sensitivity photopolymn. initiator (B), a diluent (C), a thermosetting component (D) made of an epoxy compd. having two or more epoxy groups in one molecule and 2-30 pts.wt. solid lubricant (E) basing on 100 pts.wt. of the resin A. This compsn. is applied to a substrate, exposed, developed and post-cured to form a high hardness cured coating film excellent in slidability as well as wear and scuffing resistances.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid photocurable thermosetting resin composition which can be developed with a dilute aqueous alkali solution, and more specifically, it has abrasion resistance, slidability, electrical insulation,
The present invention relates to a photocurable thermosetting resin composition which is excellent in various properties such as hardness and is useful for forming a solder resist film of a printed wiring board and an insulating resin layer of various electronic parts.

[0002]

2. Description of the Related Art Conventionally, various methods for forming a solder resist layer have been proposed and put into practical use in the process of manufacturing a printed wiring board. The main methods are (1) silk screen printing method, (2) liquid photo solder resist method, (3) dry film photo solder resist method, etc., and they are widely and generally used. These solder resists have been adjusted and put into practical use for the purpose of protecting the surface of the printed wiring board, preventing solder from adhering to unnecessary parts, ensuring electrical insulation, improving solderability, etc. In the manufacturing process, it is particularly important to secure the hardness and wear resistance of the surface of the solder resist cured coating film.

The solder resist is generally applied to a printed wiring board on which a conductor circuit is formed and cured, and is used. However, in the printed wiring board manufacturing process, the printed wiring boards are stacked, contacted with each other, or produced. The performance of the printed wiring board may be deteriorated as a result of contact with equipment and scratches on the surface of the printed wiring board to lower the commercial value, or to lower the function as a solder resist. Therefore, conventionally, in order to prevent scratches on the surface of the printed wiring board, cushioning material is added to each printed wiring board, scratches are prevented by improving handling such as stacking method, and curing reaction in the manufacturing process and ink composition. It was attempted to prevent scratches on the composition side by preventing the scratches on the surface by advancing faster and obtaining a strong coating film, and by using or using a hard filler such as alumina powder or silica powder in combination. However, neither method was satisfactory.

Further, in various electronic parts which are required to be miniaturized, there is an increasing demand for forming an insulating resin layer with a precise pattern. For example, in a slide switch or the like, the contacts are electrically insulated from each other. An insulating resin layer is embedded between each contact so as to form the same surface as each contact so that the contact arm can smoothly reciprocate. Such an insulating resin layer has slidability so that the contact arm can smoothly reciprocate, and has abrasion resistance and hardness that endure repeated sliding, and there is little change in electrical characteristics between contacts, and insulation It is required that the resistance characteristics can be maintained for a long time.

[0005]

Therefore, the main object of the present invention is to provide various properties such as wear resistance, slidability, electrical insulation, hardness, etc., and to provide a solder resist film for printed wiring boards and various electronic parts. Another object of the present invention is to provide a photocurable thermosetting resin composition that can be developed with a dilute aqueous alkali solution and is useful for forming an insulating resin layer. Further, the object of the present invention is to impart abrasion resistance, scratch resistance, and slidability to the coating film, improve the hardness of the coating film surface, and prevent the printed wiring board surface from being scratched during the printed wiring board manufacturing process. It is difficult to manufacture a high-quality printed wiring board that can sufficiently maintain the function as a solder resist, and even when it is used as an insulating resin layer for various electronic parts such as switches and slide switches, it can be used for a long time. It is an object of the present invention to provide a photocurable thermosetting resin composition that can be developed with a dilute aqueous alkali solution and that can form an insulating resin layer that can maintain insulation resistance characteristics without being worn away.

[0006]

In order to achieve the above object, according to the present invention, (A) an active energy ray curable resin having at least two ethylenically unsaturated bonds and a carboxyl group in one molecule. , (B) a high-sensitivity photopolymerization initiator, (C) a diluent, (D) a thermosetting component composed of an epoxy compound having two or more epoxy groups in one molecule, and (E) a solid lubricant. Consisting of the solid lubricant (E)
A photocurable thermosetting resin composition in a liquid state developable by a dilute aqueous alkaline solution, characterized in that it is contained in an amount of 2 to 30 parts by weight relative to 100 parts by weight of the active energy ray-curable resin. It

[0007]

The present inventor has found that the active energy ray curable resin having at least two ethylenically unsaturated bonds and a carboxyl group in one molecule, a photopolymerization initiator,
A photocurable thermosetting resin composition that can be developed with a dilute alkaline aqueous solution containing a diluent and a thermosetting component is blended with a solid lubricant in a specific quantitative ratio, and a highly sensitive photopolymerization initiator. By using the above, after the exposure, it is developed, and by further post-curing, the abrasion resistance,
It was found that a cured coating film of high hardness, which is excellent in sliding property in addition to scratch resistance, can be obtained.

When a solid lubricant is added to the resin composition,
It is known that the resulting coating film has a lubricating effect. The degree of this action is determined by the amount of the solid lubricant compounded, but in the photocurable thermosetting resin composition, the compounding of the solid lubricant particularly inhibits the photocurability,
When the solid lubricant is blended in a quantitative ratio that exerts a sufficient lubricating action, there is a problem that sufficient crosslink density cannot be obtained by irradiation with active energy rays. Further, when such a photo-cured coating film is developed with an organic solvent, the organic solvent has a strong resin-dissolving action, so the coating film on the photo-cured portion is also developed and the insulating resin layer having a predetermined pattern is formed. Is hard to get. The present invention solves such a problem by changing the blending amount of the solid lubricant to the active energy ray curable resin 100.
In addition to specifying a ratio of 2 to 30 parts by weight with respect to parts by weight, the photocurability of the resin composition should be increased, and the resin composition should be developable with a dilute alkaline aqueous solution, that is, at least two ethylenic compounds in one molecule should be used. This is solved by using an active energy ray-curable resin having both a saturated bond and a carboxyl group in combination with a highly sensitive photopolymerization initiator.

Further, the photocurable thermosetting resin composition of the present invention is applied to the entire surface of a printed wiring board on which a conductor pattern is formed of, for example, copper foil, and a predetermined exposure pattern is applied from the surface side of the applied coating film. After exposing through a photomask formed with, and developing the unexposed portion with a dilute alkaline aqueous solution,
A usual resist pattern forming method of heating and thermosetting can be applied, but particularly when exposed from the back surface of the coating film, the operation and effect peculiar to the present invention are exhibited. That is, as shown in FIG. 1, the photocurable thermosetting resin composition of the present invention is applied to the surface of a laminated plate obtained by sticking a metal foil 2 having a predetermined pattern on a transparent substrate 1 to form a coating film 3 Is formed, and after tentative drying, an active energy ray is irradiated from the back surface side of the substrate 1 to expose it,
Since the coating film portion of the surface of the metal foil 2 which does not transmit the active energy rays is not photocured, it is developed with a dilute alkaline aqueous solution. On the other hand, since the coating film portion existing between the metal foils 2 is photo-cured, it is not developed and remains as the cured coating film layer 5, but the solid lubricant fine particles 4 which do not transmit the active energy rays existing in the coating film. Therefore, the degree of photo-curing is higher in the portion closer to the back surface and lower in the portion closer to the front surface. Therefore, a part of the resin component of the surface portion of the cured coating film layer 5 formed between the metal foils 2 also dissolves in the dilute alkaline aqueous solution of the developer. As a result, as shown in the schematic view of FIG. 2, as compared with the inside of the coating film, a relatively large amount of solid lubricant fine particles 4 remain on the surface of the cured coating film layer 5 after the development treatment, and these are on the surface. It becomes exposed and the lubrication action is increased.
Therefore, the cured coating film layer formed by such a method is useful as an insulating resin layer for sliding or abrasion resistance, and is particularly suitable as an insulating resin layer for sliding such as a switch and a slide switch.

The constituent components of the photocurable thermosetting resin composition of the present invention will be described below. First, the (A) 1
Examples of the active energy ray-curable resin having at least two ethylenically unsaturated bonds and a carboxyl group in the molecule include (1) an ester of an epoxy group of a polyfunctional novolac type epoxy compound and a carboxyl group of an unsaturated monocarboxylic acid. (2) a copolymer of alkyl (meth) acrylate and glycidyl (meth) acrylate, and (meth) acrylic acid To a copolymer of saturated or unsaturated polybasic acid anhydride, and (3) a copolymer of hydroxyalkyl (meth) acrylate, alkyl (meth) acrylate and glycidyl (meth) acrylate. After reacting (meth) acrylic acid, a saturated or unsaturated polybasic acid anhydride was further reacted. Can be used (4) alkyl (meth) acrylate and (meth) obtained by reacting a glycidyl (meth) acrylate copolymers of acrylic acid, and the like.

Since the above active energy ray-curable resin has a large number of free carboxyl groups added to the side chains of the backbone polymer, it can be developed with a dilute alkaline aqueous solution, and at the same time, a coating film is formed after development. By post-heating, a copolymerization reaction occurs between the epoxy compound having two or more epoxy groups in one molecule separately added as a thermosetting compounding component and the free carboxyl group of the side chain, and the coating A solder resist film excellent in various properties such as heat resistance, solvent resistance, acid resistance, plating resistance, adhesiveness, electric characteristics and hardness can be obtained. The acid value of the active energy ray-curable resin (A) is 40 to 160 mgKOH.
/ G is necessary, and the preferable range is
In the resin of (1) above, 50 to 140 mg KOH /
g, 50 to 15 in the resins of the above (2) and (4)
0 mgKOH / g, 40 to 40 in the resin of (3) above
It is 120 mgKOH / g. If the acid value is less than 40, the alkali solubility will be poor, and if it is more than 160, on the other hand, it will be a factor of deteriorating the characteristics of the cured film as a resist such as alkali resistance and electric characteristics.

The resin (1) is a reaction product of a novolac type epoxy compound and an unsaturated monocarboxylic acid as described below, a dibasic acid anhydride such as phthalic anhydride, trimellitic anhydride, or pyromellitic anhydride. It is obtained by reacting with an aromatic polycarboxylic acid anhydride such as an acid. In this case, a resin obtained by reacting 0.15 mol or more of a polybasic acid anhydride per one hydroxyl group contained in the reaction product of the novolac type epoxy compound and the unsaturated monocarboxylic acid is suitable. When the number of ethylenically unsaturated bonds present in one molecule of the epoxy compound is low, photocurability is slow, so it is desirable to use a novolac type epoxy compound as the raw material, but for the purpose of reducing the viscosity of the ink, bisphenol A type Epoxy compounds can also be used.

Typical novolac type epoxy compounds include phenol novolac type epoxy resin, cresol novolac type epoxy resin, and bisphenol A.
There are novolac type epoxy resin, etc.
A compound obtained by reacting each novolak resin with epichlorohydrin can be used.
Examples of the unsaturated monocarboxylic acid include acrylic acid, methacrylic acid, cinnamic acid, saturated or unsaturated dibasic acid anhydrides and 1
There are reaction products with (meth) acrylates having one hydroxyl group in the molecule, and these can be used alone or in combination of two or more, but from the viewpoint of photocurability, acrylic acid or methacrylic acid, especially Acrylic acid is preferred.

As the polybasic acid anhydrides, typical examples are maleic anhydride, succinic anhydride, itaconic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydro. Phthalic anhydride, Endomethylene tetrahydrophthalic anhydride, Methyl endomethylene tetrahydrophthalic anhydride,
Dibasic acid anhydrides such as chlorendic anhydride and methyltetrahydrophthalic anhydride; aromatic polyvalent carboxylic acid anhydrides such as trimellitic anhydride, pyromellitic dianhydride, benzophenonetetracarboxylic dianhydride; etc. For example, a polyvalent carboxylic acid anhydride derivative such as 5- (2,5-dioxotetrahydrofuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride can be used.

On the other hand, the copolymer, which is the base polymer of the resins of the above (2) and (3), is an alkyl (meth) acrylate and glycidyl (meth) acrylate as a monomer as described above, or further a hydroxyalkyl (meth). It can be obtained by using an acrylate and copolymerizing them by a known method such as a solution polymerization method. The alkyl (meth) acrylate is an alkyl ester of acrylic acid or methacrylic acid,
Here, the alkyl group is an aliphatic hydrocarbon group having 1 to 6 carbon atoms. Examples of the alkyl (meth) acrylate include, but are not limited to, esters of acrylic acid or methacrylic acid such as methyl, ethyl, propyl, isopropyl, butyl, and hexyl.

The hydroxyalkyl (meth) acrylate is a hydroxyalkyl ester of acrylic acid or methacrylic acid, and the hydroxyalkyl group is preferably an aliphatic hydrocarbon group having a primary hydroxyl group and having 1 to 6 carbon atoms. . This is a hydroxyalkyl (meth) acrylate having a primary hydroxyl group in terms of easiness of reaction when further reacting the copolymer with (meth) acrylic acid and then reacting with a polybasic acid anhydride. It is desirable to select and use as one of the monomers of the copolymer. Representative examples of such a hydroxyalkyl (meth) acrylate having a primary hydroxyl group include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl acrylate, but are not limited thereto. is not.

In the copolymer (2) as the base of the resin, the molar ratio of alkyl (meth) acrylate and glycidyl (meth) acrylate is 40:60.
80:20 is preferred. On the other hand, in the copolymer as the base of the resin of (3), the ratio of hydroxy (meth) acrylate, alkyl (meth) acrylate and glycidyl (meth) acrylate is 10 to 50: molar ratio.
10 to 70:20 to 60, preferably 15 to 30:30
˜50: 30 to 50. If the proportion of glycidyl (meth) acrylate in the copolymer is lower than the above range, it is not preferable because the photocurability is lowered. On the other hand, if it exceeds the above range, the synthesis reaction of the photosensitive resin becomes smooth. It is not desirable because it is not necessary The degree of polymerization of the copolymer obtained by copolymerizing each of the above-mentioned monomers is preferably in the range of 10,000 to 70,000, preferably 20,000 to 60,000 as a weight average molecular weight.
When the weight average molecular weight is less than 10,000, the dryness to the touch is deteriorated, while when it exceeds 70,000, the developability is easily deteriorated, which is not preferable. In the present invention,
In addition to the above-mentioned monomers, vinyl compounds such as styrene and methylstyrene can also be used within a range that does not affect the characteristics.

In the present invention, a highly sensitive photopolymerization initiator is used as the (B) photopolymerization initiator. Here, the "high-sensitivity" photopolymerization initiator means, as described in the section of the action of the invention, a case where a sufficient amount of solid lubricant capable of imparting slidability and abrasion resistance to the coating film is blended. However, it means a highly sensitive photopolymerization initiator capable of exhibiting sufficient photocurability. Examples of such a highly sensitive photopolymerization initiator include the following (a)
And a combination of at least one photopolymerization initiator selected from the group (b) and at least one photopolymerization initiator selected from the group (b) below. (A) 2-Methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanone-1,2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2 , 4,6-Trimethylbenzoyl-diphenylphosphine oxide, and benzyl dimethyl ketal. (B) 4-benzoyl-4'-methyldiphenyl sulfide, 2-chlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, ethyl p-dimethylaminobenzoate , P
-Isoamyl dimethylaminobenzoate.

Another example of the highly sensitive photopolymerization initiator is an organic peroxide having a phenone group in the molecule. Examples of such organic peroxides include t-butylperoxyacetate, t-butylperoxyisobutyrate, t-butylperoxypivalate, t-butylperoxyneodecanoate and t-butylperoxy-.
2-ethylhexanoate, t-butylperoxybenzoate, t-butylperoxylaurate, t-butylperoxy-3,3,5-trimethylhexanoate, t-butylperoxymaleate, t-butylperoxyneohexano Ate, t-hexyl peroxypivalate, t-hexyl peroxy neodecanoate,
t-hexyl peroxy neohexanoate, di (t-
Butyl peroxy) adipate, di (t-butyl peroxy) isophthalate, cumyl peroxy neodecanoate, cumyl peroxy octoate, cumyl peroxy neohexanoate, 3,3 ', 4,4'-tetra (T-butylperoxycarbonyl) benzophenone,
3,3 ', 4,4'-tetra (t-amylperoxycarbonyl) benzophenone, 3,3', 4,4'-tetra (t-hexylperoxycarbonyl) benzophenone, 4-t-butylperoxycarbonylbenzophenone, 4 , 4'-di (t-butylperoxycarbonyl)
-3,3'-dicarboxylbenzophenone, 2,5-
Peroxyesters such as dimethyl-2,5-di (benzoylperoxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexyne-3, acetylcyclohexylsulfonyl peroxide; octanoyl peroxide, decanoyl peroxide, Lauroyl peroxide, acetyl peroxide, isobutyl peroxide, 3,5,5-trimethylhexanoyl peroxide, benzoyl peroxide, m-toluyl peroxide, o-methylbenzoyl peroxide, 2,4
Diacyl peroxides such as dichlorobenzoyl peroxide, p-chlorobenzoyl peroxide, and peroxysuccinic acid; di (isopropylperoxy) dicarbonate, di (2-ethylhexylperoxy) dicarbonate, di (myristylperoxy) dicarbonate, di (2-ethoxyethylperoxy) ) Dicarbonate, di (methylisopropylperoxy) dicarbonate, di (3-methyl-3-methoxybutylperoxy)
Dicarbonate, di (n-propylperoxy) dicarbonate, di (cyclohexylperoxy) dicarbonate, di (4-t-butylcyclohexylperoxy)
Dicarbonate, bis (4-t-butylcyclohexyl) peroxydicarbonate, bis (3-methyl-3)
-Methoxybutyl) peroxydicarbonate, t-butylperoxyisopropylcarbonate, t-butylperoxyallylcarbonate and other peroxycarbonates; n-butyl-4,4-bis (t-butylperoxy) valerate and other peroxys Ketals; ketone peroxides such as methyl acetoacetate peroxide; and 4- (1-t-butylperoxy-1-methylethyl) benzophenone, 4,4'-bis (1-t
-Butylperoxy-1-methylethyl) benzophenone, 4- (1-t-butylperoxy-1-methylethyl) acetophenone, 3- (1-t-butylperoxy-1-methylethyl) acetophenone, 2-t-butyl Peroxy-2-methyl-1-phenyl-propane-1
-One, 1- [4- (1-t-butylperoxy-1-
Examples thereof include dialkyl peroxides such as methylethyl) phenyl] -2-hydroxy-2-methyl-propan-1-one, and these can be used alone or in combination of two or more kinds. Of these, preferred are 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone and 3,3', 4.
4'-tetra (t-amylperoxycarbonyl) benzophenone, 3,3 ', 4,4'-tetra (t-hexylperoxycarbonyl) benzophenone, 4-t-butylperoxycarbonylbenzophenone, 4,4'-
Di (t-butylperoxycarbonyl) -3,3'-dicarboxylbenzophenone, 4- (1-t-butylperoxy-1-methylethyl) benzophenone, 4,
4'-bis (1-t-butylperoxy-1-methylethyl) benzophenone, 4- (1-t-butylperoxy-1-methylethyl) acetophenone, 3- (1-t
-Butylperoxy-1-methylethyl) acetophenone, especially 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone, 4- (1-
t-Butylperoxy-1-methylethyl) acetophenone and the like are more preferable.

In the photocurable thermosetting resin composition of the present invention, a suitable blending ratio of the highly sensitive photopolymerization initiator is 0.2 to 100 parts by weight of the active energy ray-curable resin (A). 30 parts by weight. When the compounding ratio of the photopolymerization initiator is less than 0.2 parts by weight, the photocurability is deteriorated, while when it is more than 30 parts by weight, the properties of the cured coating film are deteriorated, and the organic peroxide is also used. Is not preferable because the storage stability becomes poor.

Further, as the (C) diluent, a photopolymerizable monomer and / or an organic solvent can be used. Typical examples of the photopolymerizable monomer are 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, N-vinylpyrrolidone, acryloylmorpholine, methoxytetraethylene glycol acrylate,
Methoxy polyethylene glycol acrylate, polyethylene glycol diacrylate, N, N-dimethyl acrylamide, N-methyl acrylamide, N, N-
Dimethylaminopropyl acrylamide, N, N-dimethylaminoethyl acrylate, N, N-dimethylaminopropyl acrylate, melamine acrylate, diethylene glycol acrylate, triethylene glycol diacrylate, propylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate Acrylate, polypropylene glycol diacrylate, phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, cyclohexyl acrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate, glycerin diglycidyl ether diacrylate, glycerin triglycidyl ether triacrylate, pentaerythritol tria Relate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, isoborneolyl acrylate, cyclopentadiene mono- or di-acrylate, and each methacrylate corresponding to the above acrylate, polybasic acid and hydroxyalkyl ( Mono-, di-, tree or higher polyesters with (meth) acrylates.

On the other hand, examples of the organic solvent include ketones such as methyl ethyl ketone and cyclohexanone, aromatic hydrocarbons such as toluene and xylene, cellosolves such as cellosolve and butyl cellosolve, carbitols such as carbitol and butyl carbitol, and acetic acid. There are acetic acid esters such as ethyl, butyl acetate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate and butyl carbitol acetate.

The above-mentioned diluent (C) is used alone or as a mixture of two or more kinds. A suitable range of the amount used is 30 to 300 parts by weight, preferably 50 to 200 parts by weight, based on 100 parts by weight of the active energy ray-curable resin (A).

Here, the purpose of using the monomer is to dilute the active energy ray-curable resin so that it can be easily applied and to impart photopolymerizability. A suitable amount of the monomer is to cure the active energy ray. It is 3 to 50 parts by weight with respect to 100 parts by weight of the organic resin (A). Three
If the amount is less than 50 parts by weight, the photocurability is poor, while if it exceeds 50 parts by weight, the dryness to the touch is reduced, which is not preferable. Further, the purpose of using the organic solvent is to dissolve the active energy ray-curable resin (A), dilute it, apply it as a liquid thereby to form a film by drying and enable contact exposure. is there.

As the thermosetting component (D), bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, N-glycidyl type epoxy resin. Alternatively, an epoxy compound having two or more epoxy groups in one molecule such as an alicyclic epoxy resin can be used. Alternatively, a small amount of a known epoxy curing accelerator may be used in combination therewith to accelerate the reaction. A photocurable thermosetting resin composition containing such a thermosetting component is applied, exposed, and developed, and then the coating film is post-heated to accelerate the polymerization of the photocurable resin component and the above-mentioned thermosetting property. Through copolymerization with components, the resulting resist coating can be improved in various properties such as heat resistance, solvent resistance, acid resistance, plating resistance, adhesion, electrical properties and hardness, and is particularly useful as a solder resist. is there. The thermosetting component as described above may be mixed in advance with the photocurable resin composition (one-component type), but since it easily thickens, before application to the circuit board blank,
At the time of use, it is desirable to use a mixture of both (two-component type). The blending amount of the thermosetting component is 5 to 100 with respect to 100 parts by weight of the active energy ray-curable resin (A).
Parts by weight, preferably 15-60 parts by weight.

Further, in the photocurable thermosetting resin composition of the present invention, a solid lubricant (E) is added in order to impart slidability, abrasion resistance, scratch resistance and the like to the resulting coating film. As the solid lubricant, a lubricant having a layered structure such as molybdenum disulfide, tungsten disulfide, graphite, boron nitride, phthalocyanine and melamine, soft metals such as indium, silver and lead, magnesium, sodium, calcium and the like. Each metal soap, tetrafluoroethylene polymer,
Tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene / hexafluoropropylene / perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, tetrafluoroethylene / ethylene copolymer, trifluoro Fluoropolymers such as chloroethylene polymer, trifluorochloroethylene / ethylene copolymer, polyvinyl fluoride, polyvinylidene fluoride and the like can be mentioned. The content of these solid lubricants is preferably 2 to 30 parts by weight with respect to 100 parts by weight of the active energy ray-curable resin (A). If the content of the solid lubricant is less than 2 parts by weight, sufficient lubricating effect and slidability cannot be imparted to the coating film, while if it exceeds 30 parts by weight, photocurability is impaired and sufficient coating film properties are obtained. I can't.

The photocurable thermosetting resin composition of the present invention thus obtained contains barium sulfate, silicon oxide, talc, clay, carbonic acid, if necessary, in such a proportion that the photocurability and coating film properties are not impaired. Known conventional fillers such as calcium, phthalocyanine blue, phthalocyanine green, known conventional pigments such as titanium oxide, defoaming agents,
Various additives such as adhesion promoters or leveling agents,
Alternatively, known and commonly used polymerization inhibitors such as hydroquinone, hydroquinone monomethyl ether, pyrogallol, tertiary butyl catechol and phenothiazine may be added.

The photocurable thermosetting resin composition of the present invention is
If necessary, the viscosity is adjusted to be suitable for the coating method, and this is applied to a circuit-formed printed wiring board by a method such as a screen printing method, a curtain coating method, a spray coating method, or a roll coating method. A tack-free coating film can be formed by volatilizing and drying the organic solvent contained in the composition at a temperature of -100 ° C. After that, the resist pattern can be formed by selectively exposing the unexposed portion to an actinic ray through a patterned photomask and developing the unexposed portion with a dilute aqueous alkali solution.
By heating to a temperature of 40 to 180 ° C. and thermosetting, a solder resist film excellent in adhesion, wear resistance, hardness, solder heat resistance, chemical resistance, solvent resistance, electrical insulation, and electrolytic corrosion resistance can be obtained. It is formed. Further, since the cured film obtained by using the photocurable thermosetting resin composition of the present invention has slidability in addition to the above-mentioned characteristics, for example, the slidability of a contact contact insulating resin layer of a switch, etc. It is also useful as an insulating resin layer for various electronic parts that require abrasion resistance. In particular, as described above, by adopting the method of exposing from the back surface opposite to the coating film forming surface, the slidability and abrasion resistance of the film surface can be further enhanced.

As the alkaline aqueous solution used for the above-mentioned development, an alkaline aqueous solution of potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, amines or the like can be used. A low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a xenon lamp or a metal halide lamp is suitable as an irradiation light source for photocuring. In addition, a laser beam or the like can also be used as an active light beam for exposure.

[0030]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples. All parts and% are based on weight unless otherwise specified. Synthesis Example (Production of Resin A): Cresol novolac type epoxy resin (trade name ESCN-220HH; manufactured by Sumitomo Chemical Co., Ltd.) was dissolved in cellosolve acetate so that the solid content was 60%. Add 0.45% of triphenylphosphine as a reaction catalyst to the epoxy resin, add acrylic acid to the glycidyl group in an equivalent ratio of 1: 1 and react at 85 ° C for 8 hours while blowing dry air. Let Then, 70 mol% of succinic anhydride was reacted with the secondary hydroxyl group generated in this reaction at 85 ° C. for 2 hours to produce an alkali-soluble photosensitive resin A. The acid value of the photosensitive resin A in terms of solid content was 108.

Example 1 Photosensitive resin A 140.0 parts Trimethylolpropane triacrylate 10.0 parts (trade name KAYARAD TMPTA; manufactured by Nippon Kayaku Co., Ltd.) Cresol novolac type epoxy resin 30.0 parts (trade name Epicron N- 695; Dainippon Ink and Chemicals, Inc.) Melamine (epoxy curing accelerator) 1.0 part Silica 10.0 parts Graphite 5.0 parts (trade name: Artificial graphite fine powder UFG-10; Showa Denko KK) Cellosolve acetate 30 0.0 parts Organic peroxide 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone (trade name BTTB-50; manufactured by NOF Corporation) 5.0 parts Premixed with the above components Then, the mixture was kneaded and dispersed with a three-roll mill to obtain a photocurable thermosetting resin composition. A 35 μm copper-thick glass epoxy substrate having a circuit pattern formed by etching in advance was subjected to surface conditioning, and then the photocurable thermosetting resin composition was applied to the entire surface by a screen printing method. Then, this was temporarily dried at 60 ° C. for 35 minutes in a hot air circulation type drying furnace and cooled to room temperature. Next, using a metal halide lamp exposure device (trade name HMW680C; manufactured by Oak Manufacturing Co., Ltd.), the front surface (exposure amount 600 mJ / cm ² ) or the back surface (exposure amount 1200 m)
J / cm ² ) (for the exposure from the surface, use a negative film). After exposure, spray pressure of 2.0 kg / cm using 1% sodium carbonate aqueous solution at 30 ° C as a developing solution.
Develop at ² for 1 minute. Further, this was heat-cured at 150 ° C. for 60 minutes in a hot air circulation type drying furnace to obtain an evaluation sample.

Example 2 An evaluation sample was obtained in the same manner as in Example 1 except that 7 parts of 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone was added.

Example 3 An evaluation sample was obtained in the same manner as in Example 1 except that 10 parts of 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone was added.

Example 4 Instead of 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone in Example 1, 4,4'-di (t-butylperoxycarbonyl)-
An evaluation sample was obtained in the same manner as in Example 1 except that 5 parts of 3,3′-dicarboxylbenzophenone was blended.

Example 5 4- (1-t-butylperoxy-1-methylethyl) was used in place of 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone in Example 1.
An evaluation sample was obtained in the same manner as in Example 1 except that 5 parts of benzophenone was blended.

Example 6 4- (1-t-butylperoxy-1-methylethyl) was used in place of 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone in Example 1.
An evaluation sample was obtained according to Example 1 except that 5 parts of acetophenone was blended.

Example 7 Instead of 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone in Example 1, 2-methyl-1- [4- (methylthio) phenyl] -2 was used.
An evaluation sample was obtained in the same manner as in Example 1 except that 5 parts of morpholino-propan-1-one (trade name Irgacure 907; manufactured by Ciba-Geigy) and 0.5 part of diethylthioxanthone were mixed.

Example 8 An evaluation sample was obtained in the same manner as in Example 1 except that 10 parts of graphite was blended.

Example 9 An evaluation sample was obtained in the same manner as in Example 1 except that 15 parts of graphite was blended.

Example 10 An evaluation sample was obtained in the same manner as in Example 1 except that 10 parts of molybdenum disulfide was used instead of graphite.

Example 11 An evaluation sample was obtained in the same manner as in Example 1 except that 15 parts of tetrafluoroethylene polymer was blended in place of graphite.

Comparative Example 1 In Example 1 except that 5 parts of Irgacure 651 (manufactured by Ciba-Geigy) was blended in place of 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone in Example 1. An evaluation sample was obtained accordingly.

Comparative Example 2 An evaluation sample was obtained in the same manner as in Example 1 except that graphite was not used.

Comparative Example 3 An evaluation sample was obtained in the same manner as in Example 1 except that 10 parts of alumina powder was blended in place of graphite.

The following characteristic tests were conducted on the evaluation samples obtained in Examples 1 to 11 and Comparative Examples 1 to 3. (1) Photocurability: Examples 1 to 11 and Comparative Example 1
When the evaluation samples of to 3 were prepared, the state of the coating film after development was visually judged. The evaluation was performed according to the following criteria. ◎ ・ ・ ・ No change observed ○ ・ ・ ・ Slightly changed surface △ ・ ・ ・ Remarkably changed surface × ・ ・ ・ Something of the coating film falls off

(2) Pencil hardness ... JISK-5400
According to the above test method, a pencil hardness tester was used to display the highest hardness that does not scratch the coating when a load of 1 kg is applied. The pencil used is Mitsubishi High Uni [Mitsubishi Pencil Co., Ltd.
Product].

(3) Substrate rubbing scratches ... The cured coatings are superposed so that the surfaces thereof face each other, and a weight of 1 kg is placed thereon. Next, the coating film on which the weight is placed is moved together with the substrate on the surface of the cured coating film on the back surface at a constant speed. After repeating this operation 5 times in the same direction, the state of the coating film surface was observed with a magnifying glass. The evaluation was performed according to the following criteria. ⊚: No scratches were observed, and no change was observed in the coating film surface state before and after the test. ○: Almost no scratches were generated. B: Occurrence of scratches is observed. X: A scratch is generated and the surface of the coating film is scraped.

(4) Pressability: The cured coating film together with the base material was pressed for 300 shots in an experimental press, and the press shapes of the cured coating film at the first shot and the 300th shot were compared with a magnifying glass. In addition, the change in the wear state of the mold was observed with a magnifying glass. The evaluation was performed according to the following criteria. ⊚: There is no change in the press shape before and after pressing, and no wear is observed on the mold. ○: There is no change in the shape of the press before and after pressing, but slight wear is observed on the mold. Δ: A slight change in the press shape is observed, or a slight abrasion is observed on the mold. X: A change in the press shape is observed, and wear is observed on the mold.

(5) Electrical characteristics: The cured coating film is JIS-
Formed on the comb-shaped electrode defined in Z-3197, and
C, 90% R.C. H. The insulation resistance values after being left in the above environment were measured and compared. The evaluation was performed according to the following criteria. ⊚ ... Insulation resistance value of 1.0 × 10 ¹³ Ω or more. ○: Insulation resistance value in the range of 1.0 × 10 ^{11 to} 1.0 × 10 ¹³ Ω is shown. Δ: Insulation resistance value in the range of 1.0 × 10 ^{9 to} 1.0 × 10 ¹¹ Ω is shown. × ... Indicates an insulation resistance value of 1.0 × 10 ⁹ Ω or less. The results are shown in Table 1.

[Table 1]

[0050]

INDUSTRIAL APPLICABILITY As described above, the photocurable thermosetting resin composition of the present invention is excellent in photocurability even though it contains a solid lubricant. After exposure, development, and post-cure can be performed to obtain a high-hardness coating film having excellent wear resistance, scratch resistance, slidability, and the like. Therefore, it is not only useful as a solder resist for a printed wiring board, but also can be advantageously used for forming an insulating resin layer of various electronic components. That is, when the photocurable thermosetting resin composition of the present invention is used as a solder resist for a printed wiring board, the active energy ray-curable resin contained in the composition is a large number in the side chains of the backbone polymer. Since it has a free carboxyl group, it can be developed with a dilute aqueous alkali solution, and at the same time, after the development, the coating film is post-heated so that 2 molecules are added to one molecule added as a thermosetting compounding component. Copolymerization reaction occurs between the epoxy compound having more than one epoxy group and the free carboxyl group of the side chain, heat resistance of the coating film required as a solder resist, solvent resistance, acid resistance, plating resistance, A solder resist film with excellent properties such as adhesion, electrical properties, and hardness can be obtained, and because it contains a solid lubricant, it also has wear resistance, scratch resistance, and slidability. It has a high hardness and does not scratch the surface of the solder resist film even if it is handled in a random manner in the printed wiring board manufacturing process, and the hard coating material does not improve the coating film hardness. There is little die wear at the time of outer shape press working, and fine processing is possible. Further, when the photocurable thermosetting resin composition of the present invention is used as an insulating resin for electronic parts, for example, an insulating resin layer of a slide switch, it has sliding property to withstand repeated sliding and wear resistance, With the smooth reciprocation of the arm,
There is little change in electrical characteristics between contacts, and insulation resistance characteristics can be maintained for a long time. In particular, by adopting a method of exposing from the back surface opposite to the surface on which the coating film is formed, the slidability and abrasion resistance of the film surface are improved, and it can be used in a wide range of fields as a resin film for sliding or surface protection.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing a state in which a photocurable thermosetting resin composition of the present invention is applied onto a substrate on which a metal foil having a predetermined pattern is attached.

FIG. 2 is a partial cross-sectional view showing a state after the back surface of the substrate is exposed and then developed.

FIG. 3 is an enlarged view of part A of FIG.

[Explanation of symbols]

 1 substrate 2 metal foil 3 coating film 4 solid lubricant fine particles 5 cured coating film layer

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location G03F 7/031 C4 7/032 501 N25 H05K 3/06 H 3/28 D

Claims (6)

[Claims] 1. An active energy ray-curable resin having (A) at least two ethylenically unsaturated bonds and a carboxyl group in one molecule, (B) a highly sensitive photopolymerization initiator,
(C) a diluent, (D) a thermosetting component composed of an epoxy compound having two or more epoxy groups in one molecule, and (E) a solid lubricant, and the solid lubricant (E) A liquid photocurable thermosetting resin composition developable with a dilute alkaline aqueous solution, which is contained in a ratio of 2 to 30 parts by weight based on 100 parts by weight of the active energy ray-curable resin. 2. The active energy ray-curable resin comprises a reaction product of a novolac type epoxy compound and an unsaturated monocarboxylic acid, and a saturated or unsaturated polycarboxylic acid of 0.15 mol or more per hydroxyl group contained in the reaction product. The composition according to claim 1, which is obtained by reacting a basic acid anhydride. 3. The active energy ray-curable resin is 4
The composition according to claim 1 or 2, which has an acid value of 0 to 160 mgKOH / g. 4. The composition according to claim 1, wherein the high-sensitivity photopolymerization initiator is an organic peroxide. 5. The high-sensitivity photopolymerization initiator is added in an amount of 0.2 to 30 with respect to 100 parts by weight of the active energy ray-curable resin.
The composition according to any one of claims 1 to 4, which is contained in a ratio of parts by weight. 6. The diluent is a photopolymerizable monomer and / or an organic solvent, and is used alone or in combination in an amount of 30 to 300 parts by weight based on 100 parts by weight of the active energy ray-curable resin. The composition according to any one of 1 to 5.