Curable resin composition, electrical / electronic component, and method for manufacturing electrical / electronic component

Abstract

Provided is a curable resin composition from which a cured article having excellent adhesion to a substrate, particularly a poorly-adhesive resin substrate, can be produced. This curable resin composition comprises (A) a curable resin, (B) an ethylenically unsaturated monomer, (C) an acidic surfactant, (D) an inorganic filler, (E) a thermal polymerization initiator, and optionally a saturated polybasic acid, in which the curable resin (A) comprises at least a vinyl ester resin, the acid value of a mixture of the curable resin (A), the ethylenically unsaturated monomer (B) and the saturated polybasic acid is 12 mgKOH / g or less, the acid value of a mixture of the curable resin (A), the ethylenically unsaturated monomer (B), the acidic surfactant (C) and the saturated polybasic acid is 10 mgKOH / g or more, and the acidic surfactant (C) is a low-volatile substance having an acid value of 20 mgKOH / g or more.

Description

[Technical Field]

[0001] The present invention relates to a curable resin composition, an electric / electronic component, and a method for producing an electric / electronic component. [Background technology]

[0002] In electronic devices such as motors, coils, and electronic control units installed in automobiles, etc., in order to protect the wiring board and the electronic components mounted on the wiring board, a structure is required that can fix the components and prevent damage to the components due to vibration, and that can prevent the intrusion of water, corrosive gases, etc. In such cases, a structure is generally used in which the entire electronic component is sealed and fixed with a material called a sealant.

[0003] For example, Patent Document 1 discloses an encapsulating epoxy resin composition used to form an encapsulant that collectively seals the gap between a wiring board and an electronic component. Patent Document 2 discloses an unsaturated polyester resin composition for molding electric and electronic components, which contains 7 to 15% by weight of a novolac vinyl ester resin, 2 to 5% by weight of a bis-unsaturated polyester resin, and 65 to 80% by weight of magnesium oxide. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-148586 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-27019 Summary of the Invention [Problem to be solved by the invention]

[0005] However, epoxy resins have a problem in that the raw material cost is relatively high among resins, making them difficult to use for large products. Furthermore, epoxy resin compositions have a high molding temperature of 170 to 180°C and a long curing time, leaving room for improvement in terms of reliability, productivity, and cost of electronic devices. The resin composition disclosed in Patent Document 2 leaves room for further improvement in terms of adhesion to substrates.

[0006] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a curable resin composition that can give a cured product that has excellent adhesion to a substrate, particularly to a poorly adhesive resin substrate. Another object of the present invention is to provide an electric / electronic component that includes the cured product with excellent adhesion as an encapsulant, and a method for producing the same. [Means for solving the problem]

[0007] The present invention includes the following aspects. [1] (A) Curable resin, (B) an ethylenically unsaturated monomer, (C) an acidic surfactant, (D) Inorganic filler, (E) a thermal polymerization initiator, and Optionally, saturated polybasic acids Including, The (A) curable resin contains at least a vinyl ester resin, the mixture of the (A) curable resin, the (B) ethylenically unsaturated monomer, and the saturated polybasic acid has an acid value of 12 mgKOH / g or less; the mixture of the (A) curable resin, the (B) ethylenically unsaturated monomer, the (C) acidic surfactant, and the saturated polybasic acid has an acid value of 10 mgKOH / g or more; The (C) acidic surfactant is a low-volatile substance having an acid value of 20 mgKOH / g or more. Curable resin composition. [2] The curable resin composition according to [1], wherein the acid value of the (C) acidic surfactant is 30 to 190 mgKOH / g. [3] The curable resin composition according to either [1] or [2], wherein the (C) acidic surfactant is a phosphate ester compound. [4] The curable resin composition according to any one of [1] to [3], wherein the (B) ethylenically unsaturated monomer is styrene. [5] per 100 parts by mass of the total of (A) the curable resin, (B) the ethylenically unsaturated monomer, and any saturated polybasic acid, (A) 5 to 95 parts by mass of a curable resin, (B) 5 to 95 parts by mass of an ethylenically unsaturated monomer, (C) 0.1 to 10 parts by mass of an acidic surfactant, (D) 200 to 700 parts by mass of an inorganic filler, and (E) 0.1 to 20 parts by mass of a thermal polymerization initiator The curable resin composition according to any one of [1] to [4], comprising: [6] (F) The curable resin composition according to any one of [1] to [5], further comprising glass fibers. [7] The curable resin composition according to any one of [1] to [6], further comprising (G) a low shrinkage agent. [8] An electric / electronic part comprising a cured product of the curable resin composition according to any one of [1] to [7]. [9] A method for producing an electric / electronic component, comprising the steps of: encapsulating components of the electric / electronic component with the curable resin composition according to any one of [1] to [7]; and heat-curing the curable resin composition. [Effects of the Invention]

[0008] According to the present invention, there is provided a curable resin composition that can give a cured product having excellent adhesion to a substrate, particularly to a poorly adhesive resin substrate. Furthermore, there are also provided a cured product having excellent adhesion obtained by curing the curable resin composition, an electric / electronic component including the cured product, and a method for producing the same. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to the embodiments described below.

[0010] In this specification, "(meth)acrylic acid" means methacrylic acid or acrylic acid, and "(meth)acrylate" means acrylate or methacrylate.

[0011] The term "ethylenically unsaturated bond" refers to a double bond formed between carbon atoms excluding carbon atoms forming an aromatic ring, and the term "ethylenically unsaturated monomer" refers to a monomer having an ethylenically unsaturated bond.

[0012] 1. Curable resin composition The curable resin composition of one embodiment contains (A) a curable resin, (B) an ethylenically unsaturated monomer, (C) an acidic surfactant, (D) an inorganic filler, and (E) a thermal polymerization initiator.

[0013] The curable resin composition may further contain, as necessary, at least one selected from the group consisting of saturated polybasic acids, (F) glass fibers, and (G) low shrinkage agents.

[0014] [(A) Curing resin] The (A) curable resin is not particularly limited as long as it is a curable resin commonly used in sealing material applications. For example, a resin having a functional group capable of forming a crosslinked structure when heat-cured as a curable resin composition is preferred. Specific examples of the (A) curable resin include (A-1) vinyl ester resin, (A-2) unsaturated polyester resin, (A-3) urethane (meth)acrylate resin, (A-4) diallyl phthalate resin, and (A-5) epoxy resin. From the viewpoints of material cost and moldability, the (A) curable resin preferably contains at least (A-1) vinyl ester resin. The (A) curable resin may be used alone or in combination of two or more types.

[0015] The content of the (A-1) vinyl ester resin in the (A) curable resin is preferably 75% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more. When the content of the (A-1) vinyl ester resin is 75% by mass or more, the material cost of the curable resin composition can be reduced, and a cured product with better moldability and adhesion can be obtained. There is no particular upper limit for the content of the (A-1) vinyl ester resin in the (A) curable resin. For example, it may be 100% by mass, 97% by mass, or 95% by mass.

[0016] The content of the (A) curable resin is preferably 5 to 95 parts by mass, more preferably 20 to 75 parts by mass, and even more preferably 30 to 50 parts by mass, relative to 100 parts by mass of the total of the (A) curable resin, the (B) ethylenically unsaturated monomer, and the optional saturated polybasic acid.

[0017] <(A-1) Vinyl ester resin> (A-1) vinyl ester resins are generally compounds having a radically polymerizable unsaturated bond obtained by a ring-opening reaction between (a) an epoxy group in an epoxy compound having two or more epoxy groups and (b) a carboxy group in an unsaturated monobasic acid having a radically polymerizable unsaturated bond and a carboxy group. (A-1) vinyl ester resins are described, for example, in the Polyester Resin Handbook (published by Nikkan Kogyo Shimbun, 1988).

[0018] The (A-1) vinyl ester resin may be used alone or in combination of two or more. In terms of handling, the (A-1) vinyl ester resin is generally used after diluting with the (B) ethylenically unsaturated monomer. By using the (A-1) vinyl ester resin, the material cost of the curable resin composition can be reduced and a cured product with excellent adhesion can be obtained.

[0019] The number average molecular weight (Mn) of the (A-1) vinyl ester resin can be adjusted depending on the desired physical properties, but from the viewpoint of ease of handling, it is preferably in the range of 500 to 5,000. In this specification, the "weight average molecular weight" and "number average molecular weight" are values ​​measured using gel permeation chromatography (GPC) under the following conditions at room temperature (23°C) and determined using a standard polystyrene calibration curve. Apparatus: Shodex (registered trademark) GPC-101 (Showa Denko K.K.) Column: Shodex (registered trademark) LF-804 (Showa Denko K.K.) Column temperature: 40℃ Sample: 0.2% by mass of sample in tetrahydrofuran Flow rate: 1mL / min Eluent: tetrahydrofuran Detector: Shodex (registered trademark) RI-71S (Showa Denko K.K.)

[0020] ((a) Epoxy Compound) The (a) epoxy compound is not particularly limited as long as it is a compound having two or more epoxy groups. Preferably, it is at least one selected from the group consisting of bisphenol-type epoxy compounds and novolac phenol-type epoxy compounds, and more preferably, it is a bisphenol-type epoxy compound. By using the (A-1) vinyl ester resin using the (a) epoxy compound as a raw material, the mechanical strength and corrosion resistance of the cured product are further improved.

[0021] Examples of bisphenol epoxy compounds include those obtained by reacting a bisphenol compound such as bisphenol A, bisphenol F, bisphenol S, and tetrabromobisphenol A with epichlorohydrin and / or methylepichlorohydrin, and those obtained by reacting a condensate of a compound obtained by glycidyl etherifying one or more of the above bisphenol compounds with one or more of the above bisphenol compounds with epichlorohydrin and / or methylepichlorohydrin. From the viewpoint of durability, a reaction product of a bisphenol compound with epichlorohydrin is preferred, and a reaction product of bisphenol A with epichlorohydrin is more preferred.

[0022] Examples of novolak phenol type epoxy compounds include those obtained by reacting phenol novolak or cresol novolak with epichlorohydrin and / or methyl epichlorohydrin.

[0023] ((b) Unsaturated monobasic acid) The (b) unsaturated monobasic acid is not particularly limited as long as it is a monocarboxylic acid having an ethylenically unsaturated bond. Preferred are methacrylic acid, acrylic acid, crotonic acid, cinnamic acid, etc., more preferably acrylic acid or methacrylic acid, and even more preferably methacrylic acid from the viewpoint of the corrosion resistance of the cured product.

[0024] ((A-1) Method for synthesizing vinyl ester resin) The (A-1) vinyl ester resin can be synthesized by a known synthesis method, for example, by adding (b) an unsaturated monobasic acid to (a) an epoxy compound and an esterification catalyst in a reaction vessel capable of being heated and stirred, and reacting the components at 70 to 150°C, preferably 80 to 140°C, and more preferably 90 to 130°C.

[0025] The unreacted (b) unsaturated monobasic acid remaining after synthesis of the (A-1) vinyl ester resin is considered to be the (B) ethylenically unsaturated monomer described below.

[0026] As the esterification catalyst, for example, known catalysts such as tertiary amines such as triethylamine, N,N-dimethylbenzylamine, N,N-dimethylaniline and diazabicyclooctane, triphenylphosphine and diethylamine hydrochloride can be used.

[0027] The compounding ratio of the (a) epoxy compound and the (b) unsaturated monobasic acid is preferably such that the total number of carboxy groups in the (b) unsaturated monobasic acid is 0.3 to 1.2 moles, more preferably 0.4 to 1.1 moles, and even more preferably 0.5 to 1.0 moles, per mole of the total number of epoxy groups in the (a) epoxy compound. When the total number of carboxy groups in the (b) unsaturated monobasic acid is 0.3 moles or more, a cured product with sufficient hardness can be obtained when the curable resin composition is cured. On the other hand, when the total number of carboxy groups in the (b) unsaturated monobasic acid is 1.2 moles or less, the amount of unreacted (b) unsaturated monobasic acid can be reduced during the synthesis of the (A-1) vinyl ester resin, thereby reducing the acid value of the mixture of the (A) component and the (B) component, and thereby obtaining a cured product with better adhesion.

[0028] After synthesizing the (A-1) vinyl ester resin, any unreacted (b) unsaturated monobasic acid is not removed and can be used as the (B) ethylenically unsaturated monomer of the curable resin composition. When the curable resin composition is cured by heat, the unreacted (b) unsaturated monobasic acid may volatilize or bleed out, affecting the adhesion of the cured product. Therefore, it is desirable to reduce the content of the unreacted (b) unsaturated monobasic acid as much as possible. For example, the content of the unreacted (b) unsaturated monobasic acid is preferably 5% by mass or less, more preferably 3% by mass or less, relative to the total amount of the (A-1) vinyl ester resin and the unreacted (b) unsaturated monobasic acid.

[0029] <(A-2) Unsaturated polyester resin> The unsaturated polyester resin (A-2) is a polycondensate of a polyhydric alcohol and an unsaturated polybasic acid, or a polycondensate of a polyhydric alcohol, an unsaturated polybasic acid, and a saturated polybasic acid, and is not particularly limited.

[0030] The unsaturated polyester resin (A-2) may be used alone or in combination of two or more. By using the unsaturated polyester resin (A-2), a cured product having excellent mechanical strength and heat resistance can be obtained.

[0031] In the present disclosure, styrene monomers and the like contained in general unsaturated polyester resins are classified as (B) ethylenically unsaturated monomers.

[0032] The polyhydric alcohol is not particularly limited as long as it is a compound having two or more hydroxyl groups. Examples of polyhydric alcohols include alkylene glycols such as ethylene glycol, propylene glycol, butanediol, diethylene glycol, dipropylene glycol, triethylene glycol, pentanediol, hexanediol, neopentanediol, tetraethylene glycol, polyethylene glycol, 2-methyl-1,3-propanediol, 1,4-cyclohexanedimethanol, and hydrogenated bisphenol A; bisphenol A; alkylene oxide-modified bisphenol A such as an ethylene oxide adduct of bisphenol A and a propylene oxide adduct of bisphenol A; and glycerin. From the viewpoints of the heat resistance and mechanical strength of the cured product and the fluidity of the curable resin composition during molding, propylene glycol, dipropylene glycol, neopentanediol, hydrogenated bisphenol A, and bisphenol A are preferred, and propylene glycol is more preferred. The polyhydric alcohols may be used alone or in combination of two or more.

[0033] The unsaturated polybasic acid is not particularly limited as long as it is a compound having an ethylenically unsaturated bond and two or more carboxy groups, or an acid anhydride thereof, and known compounds can be used. Unsaturated polybasic acids having 4 to 6 carbon atoms or acid anhydrides thereof are particularly preferred because they are less expensive and can provide curable resin compositions with superior mechanical strength and heat resistance in the cured product. Examples of unsaturated polybasic acids include maleic acid, maleic anhydride, fumaric acid, citraconic acid, itaconic acid, and chloromaleic acid. Unsaturated polybasic acids selected from fumaric acid, maleic acid, maleic anhydride, and itaconic acid are more preferred. The unsaturated polybasic acids may be used alone or in combination of two or more.

[0034] Preferred combinations of polyhydric alcohols and unsaturated polybasic acids include, for example, a combination of fumaric acid and neopentanediol, a combination of maleic acid and dipropylene glycol, a combination of maleic anhydride and propylene glycol, a combination of fumaric acid and propylene glycol, a combination of fumaric acid, hydrogenated bisphenol A and propylene glycol, etc. The combinations of fumaric acid and propylene glycol and the combinations of fumaric acid, hydrogenated bisphenol A and propylene glycol are preferred because they are lower in cost and can provide a curable resin composition that has a higher heat distortion temperature of the cured product and is more excellent in mechanical strength and heat resistance.

[0035] The saturated polybasic acid is not particularly limited as long as it is a compound having no ethylenically unsaturated bond and two or more carboxy groups, or an acid anhydride thereof, and known compounds can be used. Examples of saturated polybasic acids include aromatic saturated polybasic acids or acid anhydrides thereof, such as phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, tetrachlorophthalic anhydride, tetrabromophthalic anhydride, nitrophthalic acid, and halogenated phthalic anhydride; aliphatic saturated polybasic acids, such as succinic acid, adipic acid, sebacic acid, oxalic acid, malonic acid, azelaic acid, and glutaric acid; and hexahydrophthalic anhydride. The saturated polybasic acids may be used alone or in combination of two or more.

[0036] The weight-average molecular weight (Mw) of the (A-2) unsaturated polyester resin is not particularly limited. The weight-average molecular weight of the (A-2) unsaturated polyester resin is preferably 2,000 to 25,000, more preferably 3,000 to 20,000, and even more preferably 3,500 to 10,000. If the weight-average molecular weight is 2,000 to 25,000, the moldability of the curable resin composition will be even better.

[0037] The degree of unsaturation of the (A-2) unsaturated polyester resin is preferably 50 to 100 mol %, more preferably 60 to 100 mol %, and even more preferably 70 to 100 mol %. When the degree of unsaturation is within the above range, the moldability of the curable resin composition containing the (A-2) unsaturated polyester resin is improved.

[0038] The degree of unsaturation of the (A-2) unsaturated polyester resin can be calculated by the following formula using the number of moles of the unsaturated polybasic acid and saturated polybasic acid used as raw materials. Degree of unsaturation (mol %) = {(number of moles of unsaturated polybasic acid × number of ethylenically unsaturated bonds per molecule of unsaturated polybasic acid) / (number of moles of unsaturated polybasic acid + number of moles of saturated polybasic acid)} × 100

[0039] ((A-2) Method for synthesizing unsaturated polyester resin) The (A-2) unsaturated polyester resin can be synthesized using the above-mentioned raw materials by a known method. The various conditions for synthesizing the (A-2) unsaturated polyester resin are appropriately set depending on the raw materials used and their amounts.

[0040] Generally, the esterification reaction can be carried out in a stream of an inert gas such as nitrogen gas at a temperature of 140°C to 230°C under pressure or reduced pressure. In the esterification reaction, an esterification catalyst can be used as needed. Examples of the esterification catalyst include known catalysts such as manganese acetate, dibutyltin oxide, stannous oxalate, zinc acetate, and cobalt acetate. The esterification catalysts can be used alone or in combination of two or more.

[0041] The unreacted unsaturated polybasic acid remaining after synthesis of the (A-2) unsaturated polyester resin is considered to be the (B) ethylenically unsaturated monomer described below.

[0042] In order to increase the molecular weight by improving the reaction rate and to improve adhesion by reducing the acid value, it is preferable that the equivalent weight of the hydroxyl groups of the polyhydric alcohol is in the range of 0.9 to 1.2 relative to the total amount of carboxyl groups of the unsaturated polybasic acid and any saturated polybasic acid.

[0043] After synthesis of the (A-2) unsaturated polyester resin, the unreacted unsaturated polybasic acid and any saturated polybasic acid may be present in the curable resin composition without being removed.

[0044] <(A-3) Urethane (meth)acrylate resin> As the (A-3) urethane (meth)acrylate resin, for example, a resin obtained by introducing (meth)acryloyl groups into the hydroxyl groups or isocyanato groups at both ends of a polyurethane obtained by reacting a polyhydric isocyanate with a polyhydric alcohol can be used.

[0045] As the polyhydric alcohol, the compounds described as raw materials for the (A-2) unsaturated polyester resin can be used without any particular limitation.

[0046] Examples of polyisocyanates include aliphatic polyisocyanates such as hexamethylene diisocyanate, lysine diisocyanate, lysine triisocyanate, and trimethylhexane diisocyanate; alicyclic polyisocyanates such as hydrogenated xylylene diisocyanate, isophorone diisocyanate, methylcyclohexane-2,4 (or 2,6)-diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), and 1,3-(isocyanatomethyl)cyclohexane; aromatic polyisocyanates such as tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, and triphenylmethane triisocyanate; and adducts, isocyanurates, and biurets of these polyisocyanates. Polyisocyanates may be used alone or in combination.

[0047] When introducing a (meth)acryloyl group, for example, a method of reacting a terminal isocyanato group with a hydroxyl group-containing (meth)acrylic compound, or a method of reacting a terminal hydroxyl group with an isocyanato group-containing (meth)acrylic compound such as 2-(meth)acryloyloxyethyl isocyanate, 2-(meth)acryloyloxypropyl isocyanate, or 1,1-bis(acryloyloxymethyl)ethyl isocyanate can be used. Examples of hydroxyl group-containing (meth)acrylic compounds include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, caprolactone-modified hydroxyalkyl (meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, tris(hydroxyethyl)isocyanuric acid di(meth)acrylate, pentaerythritol tri(meth)acrylate, glycerin mono(meth)acrylate, and hydroxyethyl acrylamide, with 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, caprolactone-modified hydroxyalkyl (meth)acrylate, and hydroxyethyl acrylamide being preferred. The isocyanato group-containing (meth)acrylic compounds and hydroxyl group-containing (meth)acrylic compounds may each be used alone or in combination of two or more.

[0048] Note that, after synthesis of (A-3) urethane (meth)acrylate resin, any unreacted hydroxyl group-containing (meth)acrylic compound or unreacted isocyanato group-containing (meth)acrylic compound is considered to be (B) ethylenically unsaturated monomer, which will be described later.

[0049] <(A-4) Diallyl phthalate resin> The (A-4) diallyl phthalate resin is an oligomer obtained by an esterification reaction between diallyl phthalate and a polyhydric alcohol, and any conventionally known diallyl phthalate resin can be used without particular limitation. The (A-4) diallyl phthalate resin may be used alone or in combination of two or more kinds.

[0050] After synthesis of the (A-4) diallyl phthalate resin, unreacted diallyl phthalate may remain in the curable resin composition without being removed.

[0051] <(A-5) Epoxy resin> As the (A-5) epoxy resin, the compounds described in the section (a) Epoxy Compounds can be used. The (A-5) epoxy resins may be used alone or in combination of two or more.

[0052] [(B) Ethylenically unsaturated monomer] The (B) ethylenically unsaturated monomer is not particularly limited as long as it is a monomer having an ethylenically unsaturated bond and does not fall under the category of (C) acidic surfactants described below. The (B) ethylenically unsaturated monomer may be used alone or in combination of two or more. From the viewpoint of reducing the acid value of the mixture of component (A), component (B), and any saturated polybasic acid, a compound having no carboxy group is preferred.

[0053] Specific examples include vinyl compounds such as styrene, vinyltoluene, t-butylstyrene, methoxystyrene, divinylbenzene, vinylnaphthalene, and acenaphthylene; methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, furfuryl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, and phenyl (meth)acrylate. Examples of (meth)acrylates include acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, allyl (meth)acrylate, isobornyl (meth)acrylate, acetoacetoxyethyl (meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, tricyclodecanol di(meth)acrylate, and trimethylolpropane tri(meth)acrylate. From the viewpoint of copolymerizability with component (A), vinyl compounds are preferred, and one or more selected from styrene, vinyltoluene, t-butylstyrene, and methoxystyrene are more preferred, with styrene being even more preferred.

[0054] The content of the (B) ethylenically unsaturated monomer is preferably 5 to 95 parts by mass, more preferably 25 to 80 parts by mass, and even more preferably 50 to 70 parts by mass, relative to 100 parts by mass of the total of the (A) curable resin, the (B) ethylenically unsaturated monomer, and the optional saturated polybasic acid. When the content of the (B) ethylenically unsaturated monomer is 5 parts by mass or more, the viscosity of the curable resin composition can be adjusted within an appropriate range, and good moldability is achieved. When the content of the (B) ethylenically unsaturated monomer is 95 parts by mass or less, the mechanical strength of the cured product is good.

[0055] The acid value of the mixture of (A) curable resin, (B) ethylenically unsaturated monomer, and any saturated polybasic acid is 12 mg KOH / g or less, preferably 11 mg KOH / g or less, and more preferably 10.5 mg KOH / g or less. The lower limit of the acid value of the mixture is not particularly limited, but may be, for example, 1 mg KOH / g or more, 3 mg KOH / g or more, or 5 mg KOH / g or more. The saturated polybasic acid may be unreacted saturated polybasic acid during the synthesis of (A) curable resin. When the acid value of the mixture is 12 mg KOH / g or less, the adhesion of the cured product is good.

[0056] When the content of unreacted monomers during the synthesis of the (A) curable resin, for example, unreacted (b) unsaturated monobasic acid during the synthesis of the (A-1) vinyl ester resin, or unreacted unsaturated polybasic acid and saturated polybasic acid during the synthesis of the (A-2) unsaturated polyester resin, is high, the acid value of the mixture increases due to these unreacted monomers. When a curable resin composition containing such a mixture is cured by heating, the unreacted monomers are thought to volatilize or bleed out, affecting adhesion. Therefore, the acid value of the mixture can be used as an indicator of the adhesion of the cured product of the curable resin composition.

[0057] In the present disclosure, the acid value is a value measured in accordance with JIS K0070:1992, and is measured by the following procedure.

[0058] Approximately 2 g of sample is accurately weighed into a 100 mL Erlenmeyer flask using a precision balance, and 10 mL of a 1:1 (by weight) ethanol / diethyl ether mixed solvent is added to dissolve the sample. One to three drops of phenolphthalein ethanol solution are then added to the container as an indicator, and the sample is thoroughly stirred until homogeneous. This is then titrated with 0.1 M potassium hydroxide ethanol solution, and the neutralization endpoint is reached when the indicator remains pale red for 30 seconds. The acid value of the mixture is calculated using the following formula (1) from the results. Acid value (mgKOH / g)=[B×f×5.661] / S (1) In addition, B, f, and S in the calculation formula (1) are as follows. B: Amount (mL) of 0.1M potassium hydroxide ethanol solution used f: Factor of 0.1M potassium hydroxide ethanol solution (correction for variations due to reagent lots) S: Amount of sample collected (g)

[0059] [(C) Acidic surfactant] The (C) acidic surfactant is not particularly limited as long as it is a low-volatile substance having a surface-active effect and an acid value of 20 mgKOH / g or more, and is a compound that is highly compatible with the (A) curable resin and the (B) ethylenically unsaturated monomer, and has excellent dispersibility for the (D) inorganic filler and the optional (F) glass fiber, which will be described later. When a compound corresponds to both a saturated polybasic acid and a (C) acidic surfactant, the compound is classified as a (C) acidic surfactant.

[0060] In the present disclosure, a low-volatile substance is a substance that has a weight retention rate of 90% or more when heated at 150°C for 60 minutes in an atmospheric environment. The molecular weight or weight-average molecular weight of the low-volatile substance is, for example, 500 or more, 1,000 or more, or 1,500 or more. There is no particular upper limit for the molecular weight or weight-average molecular weight of the low-volatile substance, but it may be, for example, 7,000 or less, 6,000 or less, or 5,000 or less.

[0061] As the (C) acidic surfactant, those generally known as dispersants or plasticizers for resin compositions can be suitably used. Low-volatile oligomers are preferred, and low-volatile oligomers having a constituent component containing a monomer unit such as an ethylene unit, a styrene unit, an ester unit, an ether unit, or a urethane unit, and an acid group such as a carboxy group, a sulfo group, or a phospho group are more preferred, and phosphoric acid ester compounds or carboxylic acid ester compounds are even more preferred, and phosphoric acid ester compounds containing a long-chain polyester structure are even more preferred.

[0062] In order to improve the adhesion of the cured product, it is effective to improve the wettability of the curable resin composition to the substrate (adherend), and for this purpose, it is considered important that the curable resin composition has an acid value of a certain value or more. The use of an acidic surfactant (C) having an acid value of 20 mg KOH / g or more improves the adhesion of the cured product. Furthermore, when the curable resin composition is heat-cured, a low-volatility acidic surfactant (C) is used to prevent the adhesion of the cured product from being affected by the volatilization or bleed-out of the acidic surfactant (C).

[0063] Suitable examples of the phosphate ester compound include those described in JP-A-61-194091, JP-A-3-112992, JP-A-2007-527896, and JP-A-2014-520127. Specific examples include a phosphate triester compound of methyl ester of 12-hydroxystearic acid polyester, and an ester compound of tetraphosphoric acid with polyethylene glycol monomethyl ether and an ester compound of malic acid.

[0064] As the (C) acidic surfactant, commercially available products can be used, such as BYK Additives & Instruments products under the following names: BYK W-9010, BYK W-9011, BYK P-9051, BYK P-9050, BYK P-9060, BYK P-9065, BYK P-9080, and BYK P-9085. From the viewpoint of adhesion of the cured product, BYK W-9010 and BYK P-9051 are preferred.

[0065] The acid value of (C) acidic surfactant is 20 mgKOH / g or more, preferably 30 to 190 mgKOH / g, more preferably 100 to 180 mgKOH / g, and even more preferably 120 to 160 mgKOH / g. If the acid value is less than 20 mgKOH / g, the amount of (C) acidic surfactant needs to be increased to ensure the acid value of the curable resin composition, which is likely to adversely affect the properties of the cured product, such as adhesion.

[0066] The content of (C) acidic surfactant is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 9 parts by mass, and even more preferably 1 to 8 parts by mass, per 100 parts by mass of the total of (A) curable resin, (B) ethylenically unsaturated monomer, and optional saturated polybasic acid. When the content of (C) acidic surfactant is 0.1 part by mass or more, the curable resin composition has a sufficient acid value, and a cured product with good adhesion can be obtained. When the content of (C) acidic surfactant is 10 parts by mass or less, the properties of the cured product are not adversely affected.

[0067] The acid value of the mixture of (A) curable resin, (B) ethylenically unsaturated monomer, (C) acidic surfactant, and any saturated polybasic acid is 10 mgKOH / g or more, preferably 10 to 30 mgKOH / g, and more preferably 11 to 20 mgKOH / g. When the acid value of the mixture is 10 mgKOH / g or more, the wettability of the curable resin composition to the adherend is improved, and a cured product with sufficient adhesion can be obtained.

[0068] [(D) Inorganic filler] As the (D) inorganic filler, any particulate material known in the technical field of the present invention can be used. The use of the (D) inorganic filler can reduce the molding shrinkage of the molded article, improve workability by adjusting the viscosity of the curable resin composition, or improve the strength of the molded article.

[0069] Examples of (D) inorganic fillers include calcium carbonate, silica, aluminum oxide, aluminum hydroxide, barium sulfate, calcium sulfate, calcium hydroxide, calcium oxide, magnesium oxide, magnesium hydroxide, wollastonite, clay, kaolin, mica, gypsum, silicic anhydride, and glass powder. Calcium carbonate, aluminum oxide, and aluminum hydroxide are preferred because they are inexpensive. (D) inorganic fillers may be used alone or in combination of two or more.

[0070] The average particle size of the (D) inorganic filler is preferably 1 to 100 μm, more preferably 1 to 60 μm, and even more preferably 1 to 50 μm. If the average particle size of the (D) inorganic filler is 1 μm or more, particle aggregation can be suppressed. On the other hand, if the average particle size of the (D) inorganic filler is 100 μm or less, the moldability of the curable resin composition is good.

[0071] In this specification, the term "average particle size" refers to the 50% particle size (D50) in the volume-based cumulative particle size distribution measured using a laser diffraction / scattering particle size distribution analyzer (FRA, manufactured by Microtrack Bell Co., Ltd.).

[0072] The shape of the (D) inorganic filler is not particularly limited, and examples thereof include nearly spherical, ellipsoidal, scaly, and amorphous shapes.

[0073] The amount of (D) inorganic filler is preferably 200 to 700 parts by mass, and more preferably 300 to 600 parts by mass, per 100 parts by mass of the total of (A) curable resin, (B) ethylenically unsaturated monomer, and optional saturated polybasic acid. If the amount of (D) inorganic filler is 200 parts by mass or more, the mechanical properties of the cured product will be better. If the amount of (D) inorganic filler is 700 parts by mass or less, the (D) inorganic filler will be more uniformly dispersed in the curable resin composition, allowing for the production of a homogeneous molded product.

[0074] [(E) Thermal polymerization initiator] The (E) thermal polymerization initiator is not particularly limited as long as it is a polymerization initiator that generates radicals upon heating, and examples thereof include peroxides such as diacyl peroxides, peroxyesters, hydroperoxides, dialkyl peroxides, ketone peroxides, peroxyketals, alkyl peresters, and percarbonates.

[0075] Among these peroxides, the preferred (E) thermal polymerization initiators are 1,1-di-t-hexylperoxycyclohexane, t-hexylperoxyisopropyl monocarbonate, t-butyl peroxyoctoate, t-butylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, t-amylperoxy-2-ethylhexanoate, benzoyl peroxide, 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, t-butylperoxyisopropyl carbonate, t-butyl peroxybenzoate, dicumyl peroxide, and di-t-butyl peroxide. The (E) thermal polymerization initiators may be used alone or in combination of two or more.

[0076] The amount of (E) thermal polymerization initiator is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, and even more preferably 1 to 5 parts by mass, per 100 parts by mass of the total of (A) curable resin, (B) ethylenically unsaturated monomer, and optional saturated polybasic acid. When the amount of (E) thermal polymerization initiator is 0.1 part by mass or more, the curing reaction during molding of the curable resin composition proceeds uniformly, resulting in good physical properties and appearance of the cured product. When the amount of (E) thermal polymerization initiator is 20 parts by mass or less, the storage stability of the curable resin composition is good and handling is improved.

[0077] [(F) Glass fiber] The curable resin composition may contain (F) glass fibers as needed. The (F) glass fibers are not particularly limited as long as they are fibrous materials with an aspect ratio of 3 or more. Specific examples include chopped strand glass.

[0078] The fiber length of the (F) glass fiber is preferably 20 mm or less, more preferably 10 mm or less, and even more preferably 5 mm or less. When the fiber length is 20 mm or less, the moldability of the curable resin composition is good and the appearance of the cured product is good. The fiber length is preferably 0.1 mm or more, more preferably 0.5 mm or more, and even more preferably 1 mm or more. When the fiber length is 0.1 mm or more, the strength of the cured product is good. The average fiber diameter of the (F) glass fiber is preferably 3 to 100 μm, and more preferably 5 to 30 μm.

[0079] When (F) glass fiber is used, the content is preferably 1 to 300 parts by mass, more preferably 5 to 100 parts by mass, and even more preferably 10 to 50 parts by mass, per 100 parts by mass of the total of (A) curable resin, (B) ethylenically unsaturated monomer, and optional saturated polybasic acid. When the content of (F) glass fiber is 1 part by mass or more, the mechanical properties of the molded article obtained from the curable resin composition are better. When the content of (F) glass fiber is 300 parts by mass or less, the (F) glass fiber is more uniformly dispersed in the curable resin composition, allowing for the production of a homogeneous molded article.

[0080] [(G) Low-shrinkage agent] The curable resin composition may contain a (G) low shrinkage agent, if necessary. The (G) low shrinkage agent is not particularly limited, and any agent known in the technical field of the present invention can be used. Thermoplastic resins are preferred as the (G) low shrinkage agent. Examples of the (G) low shrinkage agent include polystyrene, polyethylene, polymethyl methacrylate, polyvinyl acetate, saturated polyester, polycaprolactone, and styrene-butadiene rubber. The (G) low shrinkage agent may be used alone or in combination of two or more.

[0081] The content of the (G) low shrinkage agent is preferably 10 to 80 parts by mass, and more preferably 15 to 30 parts by mass, per 100 parts by mass of the total of the (A) curable resin, the (B) ethylenically unsaturated monomer, and the optional saturated polybasic acid. If the content of the (G) low shrinkage agent is 10 parts by mass or more, the shrinkage rate of the cured product is small, and the desired dimensional accuracy can be obtained in the molded product. If the content of the (G) low shrinkage agent is 80 parts by mass or less, the mechanical properties of the cured product are better.

[0082] [Other additives] In addition to the above components, the curable resin composition may contain components known in the technical field of the present invention, such as viscosity modifiers such as thickeners, colorants, polymerization inhibitors, and viscosity reducers, and molding aids such as mold release agents, within a range that does not impair the effects of the present invention.

[0083] The thickener is a compound other than the (D) inorganic filler that exhibits a thickening effect, and examples thereof include isocyanate compounds. The thickener may be used alone or in combination of two or more. The amount of the thickener added can be appropriately adjusted depending on the handleability, flowability, etc. required for the curable resin composition.

[0084] A colorant is used when coloring a cured product. As the colorant, various dyes, inorganic pigments, or organic pigments can be used. The colorant may be used alone or in combination of two or more types. The amount of colorant added can be adjusted appropriately depending on the degree of coloration desired in the cured product.

[0085] Examples of polymerization inhibitors include hydroquinone, trimethylhydroquinone, p-benzoquinone, naphthoquinone, t-butylhydroquinone, catechol, pt-butylcatechol, and 2,6-di-t-butyl-4-methylphenol. The polymerization inhibitors may be used alone or in combination. The amount of polymerization inhibitor added can be adjusted appropriately depending on the storage environment and period of the curable resin composition, curing conditions, and the like.

[0086] 2. Method for producing curable resin composition The curable resin composition can be produced by mixing (A) a curable resin, (B) an ethylenically unsaturated monomer, (C) an acidic surfactant, (D) an inorganic filler, (E) a thermal polymerization initiator, and, if necessary, optional components such as (F) glass fiber, (G) a shrinkage reducing agent, and other additives other than (C) the acidic surfactant, or a combination of two or more of these optional components. The curable resin composition may contain a saturated polybasic acid, and the saturated polybasic acid may be derived during the production of the (A) curable resin.

[0087] An example of the mixing method is kneading. The kneading method is not particularly limited, and examples include kneading using a kneader, disperser, planetary mixer, etc. The kneading temperature is preferably 5°C to 50°C, and more preferably 10 to 40°C.

[0088] The order in which the components are mixed when producing a curable resin composition is not particularly limited. For example, it is preferable to mix (A) the curable resin and part or all of (B) the ethylenically unsaturated monomer before mixing the other components, since this makes it easier to obtain a curable resin composition in which the components are sufficiently dispersed or uniformly mixed. At least part of (B) the ethylenically unsaturated monomer may be mixed in advance with (A) the curable resin so that it acts as a solvent, dispersion medium, etc.

[0089] When using (F) glass fibers, one mixing method involves preparing glass fibers with a predetermined fiber length distribution in advance and mixing the (F) glass fibers with a composition containing components other than the (F) glass fibers. This method allows for fine adjustment of the fiber length distribution of the (F) glass fibers. Another method involves preparing a curable resin composition containing the (F) glass fibers and then breaking the (F) glass fibers by kneading to achieve a predetermined fiber length distribution. The fiber length distribution of the (F) glass fibers can be controlled by conditions such as the type and amount of other components to be kneaded, the type of mixer, the stirring speed, the stirring temperature, and the stirring time. This method is simple because it does not require breaking the (F) glass fibers in advance.

[0090] 3. Manufacturing method of the cured product The curable resin composition can be cured by heating as needed. The conditions for curing the curable resin composition can be appropriately set depending on the materials used. An example of preferred conditions is a temperature of 120 to 180°C, more preferably 120 to 160°C, and a curing time of 1 to 30 minutes.

[0091] 4. Manufacturing method of molded body The curable resin composition can be molded into a desired shape and cured to produce a molded article containing a cured product of the curable resin composition. The molding and curing methods are not particularly limited, and methods commonly used in the technical field of the present invention, such as compression molding, transfer molding, and injection molding, can be used.

[0092] For example, there are a method in which a mold is opened and a curable resin composition is poured into the mold and cured, and a method in which a curable resin composition is poured into a closed mold through a hole in the mold such as a sprue while the mold is under reduced pressure or while pressure is applied from the outside of the mold, as typified by injection molding, and cured. The conditions for curing the curable resin composition in the mold can be set appropriately depending on the material used. An example of preferred conditions is a temperature of 120 to 180°C, more preferably 120 to 160°C, and a curing time of 1 to 30 minutes.

[0093] In one embodiment, an electric / electronic component is provided that includes a cured product of the curable resin composition. The electric / electronic component can be produced, for example, by encapsulating components of the electric / electronic component with the curable resin composition and then curing the curable resin composition by heating. The encapsulation of the components of the electric / electronic component can be achieved, for example, by injecting the curable resin composition into a housing that contains the components.

[0094] From the viewpoint of adhesion, the curable resin composition is suitable for use with polyphenylene sulfide (PPS) substrates, polybutylene terephthalate (PBT) substrates, epoxy glass substrates, and copper substrates. The curable resin composition can provide excellent adhesion, particularly to poorly adhesive resin substrates such as PPS substrates. By using the curable resin composition, it is possible to omit the surface treatment step using a primer, plasma, or the like, which is generally performed on poorly adhesive resin substrates such as PPS substrates. [Example]

[0095] EXAMPLES The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0096] An example of synthesis of the curable resin (A) is shown below.

[0097] [Synthesis Example 1] (A-1) Synthesis of vinyl ester resin A 1-L four-neck flask equipped with a thermometer, stirrer, gas inlet, and reflux condenser was charged with 478.9 g of Araldite® AER-2603 (Asahi Kasei E-Materials Corporation) bisphenol A epoxy resin with an epoxy equivalent of 188.0 and 73.1 g of methacrylic acid dissolved in 0.35 g of methylhydroquinone, and the mixture was heated with stirring. When the temperature reached 100-110°C, 146.2 g of methacrylic acid dissolved in 1.4 g of 2,4,6-tris(dimethylaminomethyl)phenol (Seikuol® TDMP, Seiko Chemical Co., Ltd.) was added dropwise over 30 minutes and the reaction was continued at 130°C. When the acid value reached 30 mgKOH / g or less, the mixture was cooled, and 389 g of styrene and 0.1 g of hydroquinone were added to synthesize a bisphenol A vinyl ester resin containing 47% styrene by weight.

[0098] [Synthesis Example 2] (A-2) Synthesis of Unsaturated Polyester Resin A four-neck flask equipped with a thermometer, stirrer, inert gas inlet, and reflux condenser was charged with 0.93 kg (9.5 mol) of maleic anhydride, 0.07 kg (0.5 mol) of phthalic anhydride, and 0.76 kg (10 mol) of propylene glycol. The mixture was heated to 200°C with stirring under a nitrogen gas stream to carry out an esterification reaction, yielding an unsaturated polyester resin. Styrene monomer was then added in an amount of 30% by mass relative to the total of the unsaturated polyester resin and styrene monomer, yielding a mixture of unsaturated polyester resin and styrene. The resulting unsaturated polyester resin had an unsaturation degree of 95 mol% and a weight-average molecular weight of 8,000.

[0099] The "weight average molecular weight" and "number average molecular weight" were measured at room temperature (23°C) using gel permeation chromatography (GPC) under the following conditions, and the values ​​were determined using a standard polystyrene calibration curve. Apparatus: Shodex (registered trademark) GPC-101 (Showa Denko K.K.) Column: Shodex (registered trademark) LF-804 (Showa Denko K.K.) Column temperature: 40℃ Sample: 0.2% by mass of sample in tetrahydrofuran Flow rate: 1mL / min Eluent: tetrahydrofuran Detector: Shodex (registered trademark) RI-71S (Showa Denko K.K.)

[0100] The other components used were as follows:

[0101] (B) Ethylenically unsaturated monomers: Styrene (Idemitsu Kosan Co., Ltd.)

[0102] (C) Acidic surfactants: BYK W-9010 (phosphate ester dispersant, acid value 129 mg KOH / g, 150°C, 60-minute weight retention rate 99% or more, BYK) BYK P-9051 (polyester dispersant, acid value 157 mg KOH / g, 150°C, 60-minute weight retention rate 99% or more, BYK)

[0103] (D) Inorganic filler: Softon 1200 (calcium carbonate, average particle size 1.80 μm, Bihoku Funka Kogyo Co., Ltd.)

[0104] (E) Thermal polymerization initiator: Luperox 575 (t-amylperoxy-2-ethylhexanoate, Arkema Yoshitomi Co., Ltd.)

[0105] (F) Glass fiber: ECS-03B173 / P9 (fiber diameter 13 μm, fiber length 3 mm, Nippon Electric Glass Co., Ltd.)

[0106] (G) Low shrinkage agent: Taketron (polyethylene powder, Takehara Chemical Industry Co., Ltd.)

[0107] (C') Other additives other than (C) acidic surfactants: Stearic acid (acid value 197 mgKOH / g, 150°C, 60-minute weight retention 89%, NOF Corporation) Lucant HC-100 (co-oligomer of ethylene and α-olefin, no acid value, Mitsui Chemicals, Inc.) Dipropylene glycol (no acid value, boiling point 232°C, Dow Chemical) HS-9817SSK (a mixture of 70% saturated polyester and 30% styrene, acid value 11.5 mg KOH / g, manufactured by Choko Materials Co., Ltd.)

[0108] Table 1 shows the acid values ​​of (C) the acidic surfactant and (C') other additives other than (C) the acidic surfactant.

[0109] [Table 1]

[0110] Example 1 (Preparation of Curable Resin Composition) (A) 100 parts by mass of the styrene-diluted bisphenol A vinyl ester resin synthesized in Synthesis Example 1 as a curable resin (containing 52 parts by mass of bisphenol A vinyl ester resin, 47 parts by mass of styrene, and 1 part by mass of unreacted methacrylic acid), (B) 40 parts by mass of styrene as an ethylenically unsaturated monomer, (C) 4 parts by mass of BYK W-9010 as an acidic surfactant, (D) 560 parts by mass of Softon 1200 as an inorganic filler, and (E) 2 parts by mass of Luperox 575 as a thermal polymerization initiator were charged into a twin-arm kneader and kneaded for 15 minutes at 30°C to produce a curable resin composition.

[0111] (Preparation of cured product) The prepared curable resin composition was used in a transfer molding machine (model MF-070, Press Machinery Co., Ltd.) at a mold temperature of 140°C and a molding pressure of 15 kgf / cm. 2 The mixture was molded under the conditions of 180 seconds and a curing time of 180 seconds, and a molded product (cured product) in the shape of a pudding cup (diameter on the substrate side: 5 mm, height: 3 mm) was obtained on a PPS (polyphenylene sulfide) substrate.

[0112] (Evaluation of adhesion of cured product to substrate) A lateral load was applied to the obtained molded article at a constant rate of 2 mm / min using a die shear tester (Daisi Corporation), and the strength at which shear failure occurred was measured five times at 25°C, and the average value was taken as the adhesion strength. The results are shown in Table 2.

[0113] <Examples 2 to 4 and Comparative Examples 1 to 7> Curable resin compositions were prepared in the same manner as in Example 1, except that the types and compositions of raw materials were changed as shown in Table 2. The parts by mass in Synthesis Example 2 refer to the total parts by mass of the (A) curable resin and unreacted saturated polybasic acid. The styrene used to dilute the (A) curable resin was excluded from the amount of component (A) blended and added to the amount of the (B) ethylenically unsaturated monomer blended. Next, cured products were prepared in the same manner as in Example 1, and adhesion evaluations were performed. The results are shown in Table 2.

[0114] <Example 5> (A) 100 parts by weight of the styrene-diluted bisphenol A vinyl ester resin synthesized in Synthesis Example 1 as the curable resin, (B) 40 parts by weight of styrene as the ethylenically unsaturated monomer, (C) 4 parts by weight of BYK W-9010 and 4 parts by weight of BYK P-9051 as acidic surfactants, (D) 560 parts by weight of Softon 1200 as the inorganic filler, (E) 2 parts by weight of Luperox 575 as the thermal polymerization initiator, and (G) 30 parts by weight of Taketron as the low-shrinkage agent were added to a twin-arm kneader and kneaded for 15 minutes at 30°C. Next, 40 parts by weight of ESC03B173 / P9 as the glass fiber (F) was added and kneaded for an additional 10 minutes at 30°C to prepare a curable resin composition. Using the resulting curable resin composition, a cured product was prepared in the same manner as in Example 1, and adhesion evaluation was performed. The results are shown in Table 2.

[0115] [Table 2-1]

[0116] [Table 2-2]

[0117] The results shown in Table 2 indicate that the molded articles of Examples 1 to 5 have high adhesion to PPS substrates. It is believed that by adjusting the acid value of the (C) acidic surfactant and the acid values ​​of the mixture of the (A) curable resin, the (B) ethylenically unsaturated monomer, the (C) acidic surfactant, and any saturated polybasic acid within the predetermined range, the wettability to the substrate is improved and high adhesion is achieved.

[0118] On the other hand, Comparative Examples 1 to 5, which did not use (C) acidic surfactant, had low adhesion. This is thought to be because the acid values ​​of the other additives were low, so the effect of improving wettability to the substrate could not be expected, or the other additives volatilized due to the mold temperature or heat generated during curing, or bled out onto the surface of the molded article, and therefore sufficient adhesion was not achieved.

[0119] Comparative Examples 6 and 7, in which the acid value of the mixture of (A) curable resin, (B) ethylenically unsaturated monomer, and any saturated polybasic acid exceeded 12 mgKOH / g, also exhibited poor adhesion. This is thought to be due to the large amount of unreacted monomer during synthesis of (A) curable resin, which volatilized or bled out, affecting adhesion. In Comparative Example 6, the molded product peeled off from the substrate immediately after molding without applying external force, making it impossible to evaluate adhesion. [Industrial Applicability]

[0120] According to the present invention, there is provided a curable resin composition that can yield a cured product that has excellent adhesion to substrates, particularly to poorly adhesive resin substrates. Also provided are an electric / electronic component that includes the cured product with excellent adhesion as an encapsulant, and a method for producing the same. The curable resin composition is preferably used for encapsulating and fixing wiring boards and electronic components mounted on the wiring boards, which are used in electronic devices such as motors, coils, connectors, and electronic control units installed in automobiles.

Claims

1. (A) Curable resin, (B) an ethylenically unsaturated monomer, (C) an acidic surfactant, (D) inorganic filler, (E) a thermal polymerization initiator, and Optionally, saturated polybasic acids Including, the (A) curable resin contains at least a vinyl ester resin, and the content of the (A-1) vinyl ester resin in the (A) curable resin is 75 mass% or more; the content of the (A) curable resin is 30 to 50 parts by mass relative to 100 parts by mass in total of the (A) curable resin, the (B) ethylenically unsaturated monomer, and the optional saturated polybasic acid, the mixture of the (A) curable resin, the (B) ethylenically unsaturated monomer, and the saturated polybasic acid has an acid value of 12 mgKOH / g or less; the mixture of the (A) curable resin, the (B) ethylenically unsaturated monomer, the (C) acidic surfactant, and the saturated polybasic acid has an acid value of 10 mgKOH / g or more; the (C) acidic surfactant is a low-volatile substance having an acid value of 20 mg KOH / g or more, The (D) inorganic filler is a particulate material. Curable resin composition.

2. 2. The curable resin composition according to claim 1, wherein the acid value of the acidic surfactant (C) is 30 to 190 mg KOH / g.

3. The curable resin composition according to claim 1 , wherein the acidic surfactant (C) is a phosphate ester compound.

4. The curable resin composition according to any one of claims 1 to 3, wherein the (B) ethylenically unsaturated monomer is styrene.

5. per 100 parts by mass of the total of (A) the curable resin, (B) the ethylenically unsaturated monomer, and any saturated polybasic acid, (B) 5 to 95 parts by mass of an ethylenically unsaturated monomer, (C) 0.1 to 10 parts by mass of an acidic surfactant, (D) 200 to 700 parts by mass of an inorganic filler, and (E) 0.1 to 20 parts by mass of a thermal polymerization initiator The curable resin composition according to any one of claims 1 to 4, comprising:

6. The curable resin composition according to any one of claims 1 to 5, further comprising (F) glass fibers.

7. The curable resin composition according to any one of claims 1 to 6, further comprising (G) a low shrinkage agent.

8. An electric / electronic part comprising a cured product of the curable resin composition according to any one of claims 1 to 7.

9. A method for producing an electric / electronic component, comprising: a step of encapsulating components of the electric / electronic component with the curable resin composition according to any one of claims 1 to 7; and a step of heat-curing the curable resin composition.

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