Phenoxy resin, resin composition thereof, cured product thereof, and method for producing the same.

Abstract

To provide a phenoxy resin that is excellent in high thermal conductance, water resistance, and solvent solubility, a resin composition including the same, and a cured product thereof.SOLUTION: A phenoxy resin is represented by the formula (1) and has a weight average molecular weight of 10,000-200,000 (where, each X is a divalent group; 5-95 mol% of X are optionally substituted phenylene groups; each Z is a hydrogen atom or a glycidyl group; and each n is 10 or more and 500 or less on average).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a phenoxy resin having high thermal conductivity and excellent solvent solubility and water resistance, a method for producing the same, and a resin composition containing the phenoxy resin and a curable resin component, and a cured product thereof. [Background technology]

[0002] Epoxy resins have excellent heat resistance, adhesive properties, water resistance, mechanical strength, and electrical properties, and are therefore used in a variety of fields, including adhesives, paints, civil engineering and construction materials, and electrical and electronic materials. In particular, in the electrical and electronic field, they are widely used in insulating casting, laminating materials, sealing materials, etc.

[0003] These epoxy resins are then given film-forming properties by increasing their molecular weight using various methods. Such high-molecular-weight epoxy resins are known as phenoxy resins. Bisphenol A-type phenoxy resins, in particular, are primarily used as base resins for paint varnishes and film molding, and are added to epoxy resin varnishes to adjust flowability and improve toughness and adhesive properties when cured. Furthermore, those containing phosphorus or bromine atoms in the skeleton are used as flame retardants incorporated into epoxy resin compositions and thermoplastic resins.

[0004] In recent years, laminate materials used in the electrical and electronic fields have become smaller, lighter, and more functional. This has created demands for multilayer circuit boards, in particular, to be more multilayered, denser, thinner, and lighter, as well as for improved reliability and moldability. Due to their aforementioned properties, epoxy resins are ideally suited for use in the field of multilayer circuit boards. However, in the electrical and electronic and power electronics fields, where electronic circuits are becoming increasingly denser and higher in frequency, the heat generated by electronic circuits is increasing, posing a challenge to the heat dissipation capabilities of epoxy resin compositions used in insulating parts. While this heat dissipation capability was traditionally met by the thermal conductivity of the filler, further advances in integration have created a demand for improved thermal conductivity in the epoxy resin matrix itself.

[0005] Patent Document 1 describes a thermosetting resin composition that uses bisphenol A epoxy resin, a phenolic curing agent, and boron nitride particles as a thermally conductive filler as a heat dissipation and insulation material for use in electrical and electronic devices. However, the bisphenol A type epoxy resin described in Patent Document 1 is insufficient in terms of fluidity and thermal conductivity.

[0006] On the other hand, several inventions have been recently disclosed that attempt to improve the thermal conductivity of epoxy resins themselves by introducing mesogenic skeletons. For example, Patent Document 2 and Non-Patent Document 1 describe the improvement of the thermal conductivity of epoxy resins by introducing various mesogenic skeletons, but these methods are not practical when considering the cost, process, hydrolysis resistance, and thermal stability.

[0007] Patent Document 3 discloses an epoxy resin with good thermal conductivity that uses only a biphenyl skeleton. However, although it has film-forming properties and does not require modification such as adding a rubber component, it has insufficient solvent solubility and heat resistance. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-193504 [Patent Document 2] Japanese Patent Application Publication No. 2020-204029 [Patent Document 3] Japanese Patent Application Laid-Open No. 2013-151672 [Non-patent literature]

[0009] [Non-Patent Document 1] The Latest Technology of Epoxy Resins for Electronic Components (CMC Publishing, 2006, Chapter 1, pp. 24-31, Chapter 5, pp. 114-121) Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention aims to solve these problems and to provide a phenoxy resin which has a high glass transition temperature, excellent solvent solubility, adhesiveness, and film-forming properties, and which can give a cured product having an excellent balance of various properties such as thermal conductivity, heat resistance, and cured product characteristics; a resin composition using the same; a circuit board material; and a cured product thereof. [Means for solving the problem]

[0011] That is, the present invention relates to a phenoxy resin represented by the following formula (1) and characterized in that the weight average molecular weight is 10,000 to 200,000. [ka] Here, X is a divalent group, and 5 to 95 mol % of X is a phenylene group represented by the following formula (2), Z is independently a hydrogen atom or a glycidyl group, and n is the average number of repetitions and is 10 or more and 500 or less. [ka] where R 1 ~R 4 are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a phenyl group.

[0012] The above X is preferably a phenylene group represented by the above formula (2) or a divalent group represented by the following formula (3). [ka] where each Y is independently an aromatic group, a fused aromatic group, an alicyclic group, or an alicyclic heterocyclic group; R 5is a direct bond, a hydrocarbon group having 1 to 20 carbon atoms, or a divalent linking group selected from the group consisting of -CO-, -O-, -S-, -SO2-, -C=C-, -C≡C-, -CO-O-, -CO-NH-, -CH=N-, -CH=NN=CH-, -N=N-, -N(O)=N-, and -C(CF3)2-.

[0013] The above X is preferably a phenylene group represented by the following formula (4) or a biphenylene group represented by the following formula (5). [ka] where R 6 , R 7 are each independently a hydrogen atom, a t-butyl group, or a t-octyl group. [ka] where R 8 ~R 15 are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a phenyl group.

[0014] The above X preferably has both a phenylene group represented by the following formula (6) and / or formula (7) and a biphenylene group represented by the following formula (8) and / or formula (9). [ka] In formula (6), t-Bu is a t-butyl group.

[0015] The present invention also relates to a phenoxy resin obtained by reacting a bifunctional epoxy resin represented by the following formula (10) with a bifunctional phenol compound represented by the following formula (11), and characterized in that the phenoxy resin has a weight-average molecular weight of 10,000 to 200,000. [ka] Here, A and B are both divalent groups, and 5 to 95 mol % of A and B combined are phenylene groups represented by the following formula (2): G is a glycidyl group, and m is the average number of repetitions and is 0 to 6. [ka] where R 1 ~R 4 are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a phenyl group.

[0016] It is preferable that the above A and / or the above B contain a phenylene group represented by the above formula (2) and a divalent group represented by the following formula (3). [ka] where each Y is independently an aromatic group, a fused aromatic group, an alicyclic group, or an alicyclic heterocyclic group; R 5 is a direct bond, a hydrocarbon group having 1 to 20 carbon atoms, or a divalent linking group selected from the group consisting of -CO-, -O-, -S-, -SO2-, -C=C-, -C≡C-, -CO-O-, -CO-NH-, -CH=N-, -CH=NN=CH-, -N=N-, -N(O)=N-, and -C(CF3)2-.

[0017] The present invention also provides a resin composition containing 0.1 to 100 parts by mass of a curing agent as a solid content per 100 parts by mass of the solid content of the phenoxy resin.

[0018] The present invention also relates to a resin composition comprising the phenoxy resin, an epoxy resin, and a curing agent, wherein the mass ratio of the phenoxy resin to the epoxy resin solid content is 99 / 1 to 1 / 99, and the curing agent is preferably contained in an amount of 0.1 to 100 parts by mass as solid content per 100 parts by mass of the total solid content of the phenoxy resin and the epoxy resin.

[0019] The curing agent is preferably at least one selected from the group consisting of acrylic ester resins, melamine resins, urea resins, phenolic resins, acid anhydride compounds, amine compounds, imidazole compounds, amide compounds, cationic polymerization initiators, organic phosphines, polyisocyanate compounds, blocked isocyanate compounds, and active ester curing agents.

[0020] The resin composition preferably further contains an inorganic filler.

[0021] The present invention also relates to a cured product obtained from the above resin composition, a circuit board material obtained from the resin composition, and a laminate for electric and electronic circuits.

[0022] The present invention also provides a method for producing the above-mentioned phenoxy resin, which comprises reacting a bifunctional epoxy resin including a bifunctional epoxy resin represented by the above formula (10) with a bifunctional phenol compound including a bifunctional phenol compound represented by the above formula (11) in the presence of a catalyst.

[0023] The present invention also provides a method for producing a phenoxy resin having a weight average molecular weight of 10,000 to 200,000, which comprises reacting a bifunctional phenol compound represented by the following formula (12) and / or formula (13) with epihalohydrin in the presence of an alkali: [ka] where R 1 ~R 4 are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a phenyl group; each Y is independently an aromatic group, a fused aromatic group, an alicyclic group, or an alicyclic heterocyclic group; R 5is a direct bond, a hydrocarbon group having 1 to 20 carbon atoms, or a divalent linking group selected from the group consisting of -CO-, -O-, -S-, -SO2-, -C=C-, -C≡C-, -CO-O-, -CO-NH-, -CH=N-, -CH=NN=CH-, -N=N-, -N(O)=N-, and -C(CF3)2-. [Effects of the Invention]

[0024] The phenoxy resin of the present invention is characterized by its high glass transition temperature and excellent solvent solubility, adhesive properties, and film-forming properties. Furthermore, resin compositions incorporating the phenoxy resin of the present invention yield cured products with thermal conductivity and heat resistance. Because the resin composition yields cured products with a good balance of electrical properties and adhesive properties, it can be advantageously used not only in the electrical and electronic fields but also in the pressure-sensitive adhesive and adhesive fields. It is particularly useful in applications such as laminates for printed wiring boards, build-up insulating layers, adhesives for flexible printed wiring boards and metal-core laminates, resist inks, liquid semiconductor encapsulants, underfill materials, die-bonding materials, and as adhesion improvers and flexibility-imparting agents in electrical and electronic applications. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a GPC chart of the phenoxy resin obtained in Example 1. [Figure 2] 1 is an IR chart of the phenoxy resin obtained in Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, embodiments of the present invention will be described in detail. The phenoxy resin of the present invention is represented by the following formula (1). [ka] Here, X is a divalent group, and 5 to 95 mol % of X is a phenylene group represented by the following formula (2). [ka]

[0027] The phenoxy resin of the present invention has a weight average molecular weight (Mw) of 10,000 to 200,000, preferably 20,000 to 150,000, more preferably 25,000 to 100,000, and even more preferably 30,000 to 80,000, as measured by gel permeation chromatography (GPC). A low Mw results in poor film formability and elongation, while a too high Mw significantly worsens the resin's handleability. The GPC measurement method follows the conditions described in the Examples.

[0028] Unless otherwise specified, the phenoxy resin of the present invention is a general term for high-molecular-weight epoxy resins having epoxy groups (glycidyl groups) at both ends, high-molecular-weight phenolic resins having phenolic hydroxyl groups at both ends, and high-molecular-weight resins in which terminal epoxy groups and terminal phenolic hydroxyl groups coexist. Since reactions at the epoxy groups are not usually taken into consideration when producing phenoxy resins, there is no need to specify the epoxy equivalent (g / eq.), but a value of 4,000 or more is sufficient. An epoxy equivalent of less than 4,000 is undesirable because of poor film-forming properties and elongation. Similarly, when taking into consideration that both ends will have phenolic hydroxyl groups, the phenolic hydroxyl group equivalent (g / eq.) should be 4,000 or more. If it is less than 4,000, film formability and elongation will be poor, which is not preferable. In other words, the phenoxy resin of the present invention preferably has an epoxy equivalent and a phenolic hydroxyl group equivalent of 4,000 or more.

[0029] In the above formula (1), X is a divalent group, and 5 to 95 mol % of X are phenylene groups represented by the above formula (2). The phenylene groups represented by formula (2) preferably account for 25 to 75 mol %, more preferably 30 to 70%, and even more preferably 40 to 60% of all X. By having the phenylene groups represented by formula (2), solvent solubility and high thermal conductivity can be achieved. Each Y is independently a hydrogen atom or a glycidyl group. n is the number of repetitions, and its average value is from 10 to 500, preferably from 25 to 400, more preferably from 50 to 350, and even more preferably from 70 to 300. n is related to the above Mw.

[0030] The proportion of phenylene groups in X can be controlled by the ratio of raw materials, as described below in the section on the production method for phenoxy resin. Therefore, in the phenoxy resin of the present invention, when a plurality of types of bifunctional phenol compounds are used as raw materials in the phenoxy resin produced by the one-stage method described below, the molar ratio of the phenylene group-containing bifunctional phenol compounds in the raw materials is regarded as the proportion of phenylene groups in X. Similarly, in the case of the phenoxy resin produced by the two-stage method described below, the molar ratio of the phenylene group-containing compounds contained in each of the bifunctional epoxy resin and bifunctional phenol compound used as raw materials is regarded as the proportion of phenylene groups in X. In this specification, a difunctional epoxy resin is an epoxy resin having substantially two epoxy groups, and a difunctional phenol compound is a hydroxy compound having substantially two phenolic hydroxyl groups.

[0031] In the above formula (2), R 1 ~R 4 are each independently either a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a phenyl group. The number of substituents other than hydrogen atoms is preferably 1 to 2, and more preferably 2.

[0032] The bonding position of the phenylene group may be any of the para, meta, and ortho positions, preferably the para and meta positions, and more preferably the para position.

[0033] The alkyl group having 1 to 8 carbon atoms may be linear, branched, or cyclic, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an isopropyl group, a sec-butyl group, a t-butyl group, an isopentyl group, a neopentyl group, a t-pentyl group, a t-octyl group, an isohexyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a methylcyclohexyl group, a cyclooctyl group, a dimethylcyclohexyl group, and an ethylcyclohexyl group.

[0034] Preferred R 1 ~R 4 is a methyl group, an ethyl group, an isopropyl group, a t-butyl group, a t-octyl group, a cyclohexyl group, or a phenyl group, and is more preferably a methyl group, an ethyl group, a t-butyl group, a t-octyl group, or a phenyl group.

[0035] Examples of the phenylene group represented by formula (2) include, but are not limited to, groups represented by the above formula (6) or formula (7) as well as groups represented by the following formulas (2a) to (2h). Among these groups, groups represented by formula (6) or formula (7) are preferred.

[0036] [ka] Here, Me is a methyl group, t-Bu is a t-butyl group, and Ph is a phenyl group.

[0037] X is a phenylene group (X 1 ) as an essential group, and a divalent group (X 2 ), as well as other groups such as naphthylene groups (X 3 ) may also be included. [ka]

[0038] X is the essential phenylene group (X1 ) and a divalent group (X 2 ) is preferably contained in an amount of 5 to 50 mol %. Other groups such as naphthylene groups (X 3 ) is preferably less than 10 mol %.

[0039] In formula (3), each Y is independently an aromatic ring group, a fused aromatic ring group, an alicyclic group, or an alicyclic heterocyclic group, and is preferably an aromatic ring group. These aromatic ring groups may have, as a substituent, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an aryl group having 6 to 11 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, an aryloxy group having 6 to 11 carbon atoms, or an aralkyloxy group having 7 to 12 carbon atoms.

[0040] The alkyl group having 1 to 10 carbon atoms may be linear, branched, or cyclic, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an isopropyl group, a sec-butyl group, a t-butyl group, an isopentyl group, a neopentyl group, a t-pentyl group, an isohexyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a methylcyclohexyl group, a cyclooctyl group, a dimethylcyclohexyl group, an ethylcyclohexyl group, a trimethylcyclohexyl group, and a cyclodecyl group.

[0041] The alkoxy group having 1 to 10 carbon atoms may be linear, branched, or cyclic, and examples thereof include a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, an n-pentyloxy group, an n-hexyloxy group, an n-heptyloxy group, an n-octyloxy group, an n-nonyloxy group, an n-decyloxy group, an isopropoxy group, a sec-butoxy group, a t-butoxy group, an isopentyloxy group, a neopentyloxy group, a t-pentyloxy group, an isohexyloxy group, a cyclopentyloxy group, a cyclohexyloxy group, a cycloheptyloxy group, a methylcyclohexyloxy group, a cyclooctyloxy group, a dimethylcyclohexyloxy group, an ethylcyclohexyloxy group, a trimethylcyclohexyloxy group, and a cyclodecyloxy group.

[0042] Examples of the aryl group or aryloxy group having 6 to 11 carbon atoms include a phenyl group, a tolyl group, an ethylphenyl group, a xylyl group, a propylphenyl group, a mesityl group, a naphthyl group, a methylnaphthyl group, a phenoxy group, a tolyloxy group, an ethylphenoxy group, a xylyloxy group, a propylphenoxy group, a mesityloxy group, a naphthyloxy group, and a methylnaphthyloxy group.

[0043] Examples of the aralkyl group or aralkyloxy group having 7 to 12 carbon atoms include a benzyl group, a methylbenzyl group, a dimethylbenzyl group, a trimethylbenzyl group, a phenethyl group, a 1-phenylethyl group, a 2-phenylisopropyl group, a naphthylmethyl group, a benzyloxy group, a methylbenzyloxy group, a dimethylbenzyloxy group, a trimethylbenzyloxy group, a phenethyloxy group, a 1-phenylethyloxy group, a 2-phenylisopropyloxy group, and a naphthylmethyloxy group.

[0044] The above Y is preferably a phenylene group, a naphthylene group, or an aromatic ring group in which a methyl group or a 1-phenylethyl group is substituted on one of these groups.

[0045] Above R 5is a direct bond, a hydrocarbon group having 1 to 20 carbon atoms, or a divalent linking group selected from the group consisting of -CO-, -O-, -S-, -SO2-, -C=C-, -C≡C-, -CO-O-, -CO-NH-, -CH=N-, -CH=NN=CH-, -N=N-, -N(O)=N-, and -C(CF3)2-.

[0046] Examples of the hydrocarbon group having 1 to 20 carbon atoms include -CH2-, -CH(CH3)-, -C2H4-, -C(CH3)2-, cyclohexylene group, trimethylcyclohexylene group, cyclododecylene group, cyclopentylidene group, methylcyclopentylidene group, trimethylcyclopentylidene group, cyclooctylidene group, cyclododecylidene group, bicyclo[4.4.0]decylidene group, bicyclohexanediyl group, fluorene group, phenylene group, xylylene group, phenylmethylene group, diphenylmethylene group, norbornylene group, adamantylene group, tetrahydrodicyclopentadienylene group, tetrahydrotricyclopentadienylene group, norbornane structure, tetrahydrodicyclopentadiene structure, tetrahydrotricyclopentadiene structure, etc.

[0047] Preferred R 5 Examples of the alkyl group include a direct bond, -CH2-, -CH(CH3)-, -C(CH3)2-, -CO-, -O-, -S-, -SO2-, a cyclohexylene group, a trimethylcyclohexylene group, a cyclooctylidene group, a cyclododecylidene group, a bicyclohexanediyl group, a fluorene group, a phenylmethylene group, and a divalent group having a tetrahydrodicyclopentadiene structure, of which a direct bond, -CH2-, -C(CH3)2-, -CO-, -SO2-, a trimethylcyclohexylene group, a fluorene group, a phenylmethylene group, and a divalent group having a tetrahydrodicyclopentadiene structure are more preferred.

[0048] In formula (1), X is a phenylene group (X 1 ) and a biphenyl group (X 2 ), and preferably has a phenylene group (X 1) is more preferably a group represented by the following formula (6) or (7), and a biphenyl group (X 2 ) is more preferably a group represented by the following formula (8) or (9). [ka] where R 6 , R 7 are each independently a hydrogen atom, a t-butyl group, or a t-octyl group. [ka] where R 8 ~R 15 are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a phenyl group. [ka] In formula (6), t-Bu is a t-butyl group.

[0049] The phenoxy resin of the present invention can be produced by either the one-stage method or the two-stage method shown below, but is not limited to these. The phenoxy resin of the present invention may be produced by either method, but since phenoxy resin is generally easier to obtain by the two-stage method than by the one-stage method, it is preferable to use the two-stage method.

[0050] In the one-step method, an epihalohydrin such as epichlorohydrin or epibromohydrin is reacted with a mixture containing a bifunctional phenol compound having a phenylene group represented by the following formula (12) as an essential component, preferably a bifunctional phenol compound represented by the following formula (13), in the presence of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide. [ka] where Y, R 1 ~R 5 has the same meaning as the above-mentioned formulas (2) and (3).

[0051] In the two-step method, a bifunctional epoxy resin represented by the following formula (10) is reacted with a bifunctional phenol compound represented by the following formula (11) generally in the presence of a catalyst, and one or both of the bifunctional epoxy resin and the bifunctional phenol compound have a phenylene group represented by the above formula (2). [ka] Here, A and B are both divalent groups containing at least one phenylene group represented by the above formula (2). G is a glycyl group. m is the number of repetitions, and its average value is 0 to 6, preferably 0 to 3, and more preferably 0 to 1.

[0052] The weight average molecular weight and epoxy equivalent of the phenoxy resin can be produced within the desired range by adjusting the molar ratio of the epihalohydrin and the bifunctional phenol compound in the one-stage process, or by adjusting the molar ratio of the bifunctional epoxy resin and the bifunctional phenol compound in the two-stage process.

[0053] The bifunctional phenol compound used in the production of the one-stage method and the two-stage method is essentially a bifunctional phenol compound having a phenylene group represented by the above formula (12), and other bifunctional phenol compounds are used in combination. Examples of bifunctional phenol compounds that may be used in combination include bisphenols such as bisphenol A, bisphenol F, bisphenol S, bisphenol B, bisphenol E, bisphenol C, and bisphenolacetophenone, biphenols, monocyclic bifunctional phenols such as catechol, resorcinol, and hydroquinone, and dihydroxynaphthalenes. These bifunctional phenol compounds may also be substituted with a non-detrimental substituent such as an alkyl group or an aryl group. Multiple types of these bifunctional phenol compounds may also be used in combination. Among these, a bifunctional phenol compound represented by the above formula (13) which gives the above formula (3) is preferred. Here, the bifunctional phenol compound has a broad meaning and is essentially synonymous with a bifunctional hydroxy compound having two phenolic hydroxyl groups.

[0054] First, the one-stage method will be described. In the one-step process, 0.985 to 1.015 moles, preferably 0.99 to 1.012 moles, and more preferably 0.995 to 1.01 moles of epihalohydrin are reacted with 1 mole of bifunctional phenol compound in a non-reactive solvent in the presence of an alkali metal hydroxide, and the condensation reaction is carried out until the epihalohydrin is consumed and the weight-average molecular weight is 10,000 or more, thereby obtaining a phenoxy resin. After completion of the reaction, it is necessary to remove by-product salts by filtration or washing with water.

[0055] The proportion of the bifunctional phenol compound having a phenylene group represented by formula (12), which is an essential component used as a raw material, in the raw material bifunctional phenol compound is 5 to 95 mol %, preferably 25 to 75 mol %, more preferably 30 to 70 mol %, and even more preferably 40 to 60 mol %.

[0056] This reaction can be carried out under normal pressure or under reduced pressure. In the case of a reaction under normal pressure, the reaction temperature is preferably 20 to 200°C, more preferably 30 to 170°C, even more preferably 40 to 150°C, and particularly preferably 50 to 100°C. In the case of a reaction under reduced pressure, the reaction temperature is preferably 20 to 100°C, more preferably 30 to 90°C, and even more preferably 35 to 80°C. If the reaction temperature is within this range, side reactions are unlikely to occur and the reaction is likely to proceed. The reaction pressure is usually normal pressure. Furthermore, when heat of reaction needs to be removed, this is usually achieved by evaporation / condensation / refluxing of the solvent used using the reaction heat, indirect cooling, or a combination of these.

[0057] Examples of non-reactive solvents include aromatic hydrocarbons such as toluene and xylene, ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone and cyclohexanone, ethers such as dibutyl ether, dioxane and tetrahydrofuran, alcohols such as ethanol, isopropyl alcohol and butyl alcohol, cellosolves such as methyl cellosolve and ethyl cellosolve, and glycol ethers such as ethylene glycol dimethyl ether, but are not particularly limited to these. These solvents may be used alone or in combination of two or more.

[0058] A catalyst can also be used. Examples of catalysts that can be used include quaternary ammonium salts such as tetramethylammonium chloride and tetraethylammonium bromide, tertiary amines such as benzyldimethylamine and 2,4,6-tris(dimethylaminomethyl)phenol, imidazoles such as 2-ethyl-4-methylimidazole and 2-phenylimidazole, phosphonium salts such as ethyltriphenylphosphonium iodide, and phosphines such as triphenylphosphine. These catalysts can be used alone or in combination of two or more.

[0059] Next, the two-stage method will be described. The phenoxy resin of the present invention is obtained by reacting a bifunctional epoxy resin with a bifunctional phenolic compound. At least one of the bifunctional epoxy resin and the bifunctional phenolic compound must have a phenylene group represented by the formula (2). The proportion of the bifunctional epoxy resin and the bifunctional phenolic compound having the phenylene group is 5 to 95 mol%, preferably 25 to 75 mol%, more preferably 30 to 70 mol%, and even more preferably 40 to 60 mol%, based on the total number of moles of the bifunctional epoxy resin and the bifunctional phenolic compound.

[0060] The bifunctional epoxy resin used as the starting epoxy resin in the two-stage process is not particularly limited as long as it is a bifunctional epoxy resin, and is preferably a bifunctional epoxy resin represented by the above formula (10) obtained by reacting a bifunctional phenol compound having a phenylene group represented by the above formula (2) with epihalohydrin.

[0061] In the reaction of a bifunctional phenol compound with epihalohydrin to obtain the starting epoxy resin in the two-stage process, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is used in an amount of 0.80 to 1.20 times by mole, preferably 0.85 to 1.05 times by mole, relative to the functional groups in the bifunctional phenol compound. Less than this amount is undesirable because the amount of residual hydrolyzable chlorine increases. The metal hydroxide is used in the form of an aqueous solution, an alcohol solution, or a solid.

[0062] In the epoxidation reaction, an excess amount of epihalohydrin is used relative to the bifunctional phenol compound. Typically, 1.5 to 15 moles of epihalohydrin are used per mole of functional groups in the bifunctional phenol compound, preferably 2 to 10 moles, and more preferably 5 to 8 moles. If the amount is greater than this, production efficiency decreases, and if it is less than this, the amount of high molecular weight epoxy resin produced increases, making it unsuitable as a raw material for phenoxy resin.

[0063] The epoxidation reaction is usually carried out at a temperature of 120°C or lower. If the reaction temperature is high, the amount of so-called difficultly hydrolyzable chlorine increases, making it difficult to achieve high purification. The temperature is preferably 100°C or lower, and more preferably 85°C or lower.

[0064] The bifunctional epoxy resin used as the raw material for the two-stage process is preferably a bifunctional epoxy resin represented by formula (10). However, other bifunctional epoxy resins may be used in combination as long as the objectives of the present invention are not impaired. Examples of bifunctional epoxy resins that can be used in combination include bisphenol-type epoxy resins such as bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, bisphenolacetophenone-type epoxy resins, diphenyl sulfide-type epoxy resins, and diphenyl ether-type epoxy resins; monocyclic bifunctional phenol diglycidyl ethers such as biphenol-type epoxy resins and hydroquinone-type epoxy resins; dihydroxynaphthalene-type epoxy resins; diphenyldicyclopentadiene-type epoxy resins; alkylene glycol-type epoxy resins; and aliphatic cyclic epoxy resins. These epoxy resins may be substituted with non-detrimental substituents such as alkyl groups and aryl groups. Multiple types of these epoxy resins may be used in combination. Among these, epoxy resins having a divalent group represented by formula (3) are preferred.

[0065] In the two-step process, a catalyst can be used, and any compound having catalytic activity that promotes the reaction between the epoxy group and the phenolic hydroxyl group can be used. Examples of the catalyst include alkali metal compounds, organophosphorus compounds, tertiary amines, quaternary ammonium salts, cyclic amines, and imidazoles. These catalysts can be used alone or in combination of two or more.

[0066] Examples of alkali metal compounds include alkali metal hydroxides such as sodium hydroxide, lithium hydroxide, and potassium hydroxide; alkali metal salts such as sodium carbonate, sodium bicarbonate, sodium chloride, lithium chloride, and potassium chloride; alkali metal alkoxides such as sodium methoxide and sodium ethoxide; alkali metal phenoxides; sodium hydride, lithium hydride, and alkali metal salts of organic acids such as sodium acetate and sodium stearate.

[0067] Examples of organic phosphorus compounds include tri-n-propylphosphine, tri-n-butylphosphine, triphenylphosphine, tetramethylphosphonium bromide, tetramethylphosphonium iodide, tetramethylphosphonium hydroxide, trimethylcyclohexylphosphonium chloride, trimethylcyclohexylphosphonium bromide, trimethylbenzylphosphonium chloride, trimethylbenzylphosphonium bromide, tetraphenylphosphonium bromide, triphenylmethylphosphonium bromide, triphenylmethylphosphonium iodide, triphenylethylphosphonium chloride, triphenylethylphosphonium bromide, triphenylethylphosphonium iodide, triphenylbenzylphosphonium chloride, and triphenylbenzylphosphonium bromide.

[0068] Examples of tertiary amines include triethylamine, tri-n-propylamine, tri-n-butylamine, triethanolamine, benzyldimethylamine, etc. Examples of quaternary ammonium salts include tetramethylammonium chloride, tetramethylammonium bromide, tetramethylammonium hydroxide, triethylmethylammonium chloride, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium iodide, tetrapropylammonium bromide, tetrapropylammonium hydroxide, tetrabutylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium iodide, benzyltrimethylammonium chloride, benzyltrimethylammonium bromide, benzyltrimethylammonium hydroxide, benzyltributylammonium chloride, phenyltrimethylammonium chloride, etc.

[0069] Examples of imidazoles include 2-methylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, and 1-benzyl-2-phenylimidazole.

[0070] Examples of cyclic amines include 1,4-diazabicyclo[2,2,2]octane (DABCO), 1,8-diazabicyclo[5,4,0]-7-undecene (DBU), 1,5-diazabicyclo[4,3,0]-5-nonene (DBN), tetrahydro-1,4-(morpholine), N-methylmorpholine, and N,N-dimethylaminopyridine (DMAP).

[0071] Typically, the amount of catalyst used is 0.001 to 1% by mass based on the reaction solid content. When an alkali metal compound is used as a catalyst, the alkali metal remains in the phenoxy resin and deteriorates the insulating properties of electronic / electrical components and printed wiring boards using the phenoxy resin. Therefore, the total content of alkali metals such as lithium, sodium, and potassium in the phenoxy resin is preferably 100 ppm by mass or less, more preferably 60 ppm by mass or less, and even more preferably 50 ppm by mass or less. Furthermore, when organic phosphorus compounds, tertiary amines, quaternary ammonium salts, cyclic amines, imidazoles, etc. are used as catalysts, they remain in the phenoxy resin as catalyst residues and, like the alkali metal residues, deteriorate the insulating properties of electronic / electrical components and printed wiring boards. Therefore, the content of phosphorus atoms or nitrogen atoms in the phenoxy resin is preferably 300 ppm by mass or less, more preferably 200 ppm by mass or less, and even more preferably 100 ppm by mass or less.

[0072] In the two-stage process, a solvent may be used. Any solvent may be used as long as it dissolves the phenoxy resin and does not adversely affect the reaction. Examples of the solvent include aromatic hydrocarbons, ketones, ester solvents, ether solvents, amide solvents, glycol ether solvents, etc. These solvents may be used alone or in combination of two or more.

[0073] Examples of aromatic hydrocarbons include benzene, toluene, and xylene.

[0074] Examples of ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, 2-heptanone, 4-heptanone, 2-octanone, cyclopentanone, cyclohexanone, and acetylacetone.

[0075] Examples of ester solvents include methyl acetate, ethyl acetate, propyl acetate, butyl acetate, benzyl acetate, ethyl propionate, ethyl butyrate, butyl butyrate, valerolactone, and butyrolactone.

[0076] Examples of ether solvents include diethyl ether, dibutyl ether, t-butyl methyl ether, tetrahydrofuran, and dioxane.

[0077] Examples of amide solvents include formamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, 2-pyrrolidone, and N-methylpyrrolidone.

[0078] Examples of glycol ether solvents include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol dimethyl ether, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether, propylene glycol mono-n-butyl ether, and propylene glycol monomethyl ether acetate.

[0079] The amount of solvent used can be appropriately selected depending on the reaction conditions. For example, in the case of a two-stage process, a solids concentration of 35 to 95% by mass is preferred. If a highly viscous product is produced during the reaction, the reaction can be continued by adding solvent during the reaction. After the reaction is complete, the solvent can be removed by distillation or the like, or more solvent can be added, as necessary.

[0080] In the two-stage process, the reaction temperature is maintained within a temperature range that does not decompose the catalyst used. If the reaction temperature is too high, the resulting phenoxy resin may deteriorate, while if it is too low, the reaction may not proceed and the target molecular weight may not be achieved. Therefore, the reaction temperature is preferably 50 to 230°C, more preferably 100 to 210°C, and even more preferably 120 to 200°C. The reaction time is typically 1 to 12 hours, preferably 3 to 10 hours. When using a low-boiling solvent such as acetone or methyl ethyl ketone, the reaction temperature can be maintained by conducting the reaction under high pressure using an autoclave. Furthermore, if the heat of reaction needs to be removed, this is usually achieved by evaporation, condensation, and reflux of the solvent using the heat of reaction, indirect cooling, or a combination of these.

[0081] The epoxy equivalent (g / eq.) of the phenoxy resin of the present invention is not particularly limited, but is preferably 1,000 to 50,000, more preferably 3,000 to 30,000, even more preferably 4,000 to 20,000, and particularly preferably 5,000 to 15,000. If the epoxy equivalent is too low, the film-forming properties of the phenoxy resin, as well as the elongation and flexibility during film formation, may be impaired. On the other hand, if the epoxy equivalent is too high, the reactivity during curing may be impaired. The epoxy equivalent of the phenoxy resin can be determined by the method described in the Examples.

[0082] The phenoxy resin of the present invention is a flexible thermoplastic resin in itself and can be used alone, but can also be blended with a crosslinking agent or a curable resin component to form a thermosetting resin composition.

[0083] Examples of crosslinking agents or curable resin components include epoxy resins, acrylic ester resins, phenolic resins, melamine resins, urea resins, unsaturated polyester resins, alkyd resins, thermosetting polyimide resins, acid anhydride compounds, polyisocyanate compounds, and blocked isocyanate compounds. Among these, epoxy resins, phenolic resins, melamine resins, acid anhydride compounds, polyisocyanate compounds, and blocked isocyanate compounds are preferred, and bifunctional or higher epoxy resins, epoxy resin curing agents, and curing accelerators are more preferred. These crosslinking agents or curable resin components may be used alone or in combination of two or more types.

[0084] Examples of the curable resin component include a resin composition that cures an epoxy resin with a curing agent, a resin composition that cures an acrylic ester resin with a radical polymerization initiator, and a resin component that self-polymerizes a phenolic resin, a melamine resin, or the like by heat. Examples of the crosslinking agent include compounds that undergo addition polymerization with the secondary alcoholic hydroxyl group of a phenoxy resin, such as an acid anhydride compound, a polyisocyanate compound, and a blocked isocyanate compound.

[0085] The blending amount of the crosslinking agent or curable resin component is preferably 1 / 99 to 99 / 1, more preferably 10 / 90 to 90 / 10, and even more preferably 25 / 75 to 75 / 25, as a phenoxy resin / curable resin component (mass ratio). By blending the curable resin component, a material with even better heat resistance can be obtained.

[0086] When the curable resin component is an epoxy resin, conventionally known epoxy resins can be used. The term "epoxy resin" refers to an epoxy resin having at least one epoxy group, but epoxy resins having two or more epoxy groups are preferred, and epoxy resins having three or more epoxy groups are more preferred. Specific examples include polyglycidyl ether compounds, polyglycidyl amine compounds, polyglycidyl ester compounds, alicyclic epoxy compounds, and other modified epoxy resins. These epoxy resins may be used alone, or two or more types of epoxy resins of the same type may be used in combination, or epoxy resins of different types may be used in combination.

[0087] Specific examples of the polyglycidyl ether compound include bisphenol A type epoxy resins, bisphenol F type epoxy resins, tetramethylbisphenol F type epoxy resins, biphenol type epoxy resins, hydroquinone type epoxy resins, bisphenol fluorene type epoxy resins, naphthalenediol type epoxy resins, bisphenol S type epoxy resins, diphenyl sulfide type epoxy resins, diphenyl ether type epoxy resins, resorcinol type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, alkyl novolac type epoxy resins, styrenated phenol novolac type epoxy resins, bisphenol novolac type epoxy resins, naphthol novolac type epoxy resins, β-naphthol aralkyl type epoxy resins, naphthalenediol aralkyl type epoxy resins, α-naphthol aralkyl type epoxy resins, biphenyl aralkyl phenol type epoxy resins, trihydroxyphenylmethane type epoxy resins, tetrahydroxyphenylethane type epoxy resins, dicyclopentadiene type epoxy resins, alkylene glycol type epoxy resins, and aliphatic cyclic epoxy resins.

[0088] Specific examples of polyglycidylamine compounds include diaminodiphenylmethane-type epoxy resins, metaxylenediamine-type epoxy resins, 1,3-bisaminomethylcyclohexane-type epoxy resins, isocyanurate-type epoxy resins, aniline-type epoxy resins, hydantoin-type epoxy resins, and aminophenol-type epoxy resins.

[0089] Specific examples of the polyglycidyl ester compound include dimer acid type epoxy resins, hexahydrophthalic acid type epoxy resins, and trimellitic acid type epoxy resins.

[0090] Examples of the alicyclic epoxy compound include aliphatic cyclic epoxy resins such as CELLOXIDE 2021 (manufactured by Daicel Chemical Industries, Ltd.).

[0091] Specific examples of other modified epoxy resins include urethane-modified epoxy resins, oxazolidone ring-containing epoxy resins, epoxy-modified polybutadiene rubber derivatives, carboxyl-terminated butadiene nitrile rubber (CTBN)-modified epoxy resins, polyvinylarene polyoxides (e.g., divinylbenzene dioxide, trivinylnaphthalene trioxide, etc.), and phenoxy resins.

[0092] When an epoxy resin is used, a curing agent is also included. A curing agent is a substance that contributes to the crosslinking reaction and / or chain extension reaction between the epoxy groups of the epoxy resin.

[0093] The amount of the curing agent to be added is 0.1 to 100 parts by mass, preferably 1 to 80 parts by mass, more preferably 5 to 60 parts by mass, and even more preferably 10 to 60 parts by mass, based on 100 parts by mass of the epoxy resin.

[0094] The curing agent is not particularly limited, and any commonly known epoxy resin curing agent can be used. Phenolic curing agents, amide curing agents, and imidazoles are preferred from the viewpoint of improving heat resistance. Active ester curing agents are preferred from the viewpoint of reducing water absorption. Other examples include amine curing agents, acid anhydride curing agents, organic phosphines, phosphonium salts, benzo compounds, tetraphenylboron salts, organic acid dihydrazides, boron halide amine complexes, polymercaptan curing agents, isocyanate curing agents, and blocked isocyanate curing agents. These curing agents may be used alone, in combination of two or more of the same type, or in combination of different types.

[0095] Examples of phenol-based curing agents include dihydric phenol compounds such as bisphenol A, bisphenol F, dihydroxydiphenylmethane, dihydroxydiphenyl ether, bis(hydroxyphenoxy)benzene, dihydroxydiphenyl sulfide, dihydroxydiphenyl ketone, dihydroxydiphenyl sulfone, fluorene bisphenol, hydroquinone, resorcinol, catechol, t-butylcatechol, t-butylhydroquinone, dihydroxynaphthalene, and dihydroxymethylnaphthalene; phenol novolac, bisphenol A novolac, cresol novolac, xylenol novolac, trishydroxybenzoates, and the like. Examples of suitable curing agents include trivalent or higher phenolic compounds such as diphenylmethane novolac, dicyclopentadiene phenol, naphthol novolac, styrenated phenol novolac, terpene phenol, heavy oil-modified phenol, phenol aralkyl, naphthol aralkyl, polyhydroxystyrene, fluoroglycinol, pyrogallol, t-butylpyrogallol, benzenetriol, trihydroxynaphthalene, trihydroxybenzophenone, and trihydroxyacetophenone, as well as phosphorus-containing phenolic compounds such as 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide. These phenolic compounds may also be reacted with indene or styrene to form the curing agent. The phenolic curing agent is preferably used in a molar ratio of active hydroxyl groups in the curing agent to epoxy groups in the epoxy resin of 0.8 to 1.5.

[0096] Examples of amide-based curing agents include dicyandiamide and its derivatives, polyamide resins, etc. The amide-based curing agent is preferably used in an amount of 0.1 to 25 parts by mass per 100 parts by mass of the total epoxy resin component.

[0097] The imidazoles are not particularly limited as long as they are compounds having an imidazole skeleton, and examples thereof include 2-phenylimidazole, 2-ethyl-4-methylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyano-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1')] Examples of suitable epoxy resins include 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and adducts of epoxy resins with the above imidazoles. The imidazoles are preferably used in an amount of 0.1 to 25 parts by mass per 100 parts by mass of the total epoxy resin components. Because imidazoles have catalytic activity, they are generally also classified as curing accelerators, as described below.

[0098] Preferred active ester curing agents include compounds having two or more highly reactive ester groups per molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds. Among these, phenol esters obtained by reacting a polyfunctional phenol compound with an aromatic carboxylic acid, as described in Japanese Patent Publication No. 5152445, are particularly preferred. Examples of carboxylic acid compounds include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid. Examples of aromatic compounds having a phenolic hydroxyl group include catechol, dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, dicyclopentadienyl diphenol, and phenol novolac. Commercially available products include, but are not limited to, Epicron HPC-8000-65T (manufactured by DIC Corporation). The active ester curing agent is preferably used in such a manner that the molar ratio of the active ester groups in the curing agent to the epoxy groups in the resin composition is in the range of 0.2 to 2.0.

[0099] Examples of amine-based curing agents include amine-based compounds such as diethylenetriamine, triethylenetetramine, metaxylenediamine, isophoronediamine, diaminodiphenylmethane, diaminodiphenylsulfone, diaminodiphenylether, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, dicyandiamide, and polyamidoamines, which are condensates of acids such as dimer acid with polyamines. The amine-based curing agent is preferably used in a molar ratio of active hydrogen groups in the curing agent to epoxy groups in the resin composition in the range of 0.5 to 1.5.

[0100] Examples of acid anhydride curing agents include methyltetrahydrophthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, pyromellitic anhydride, phthalic anhydride, trimellitic anhydride, methylnadic anhydride, maleic anhydride, etc. The acid anhydride curing agent is preferably used in a molar ratio of acid anhydride groups in the curing agent to epoxy groups in the resin composition in the range of 0.5 to 1.5.

[0101] Active hydrogen groups are functional groups containing active hydrogen reactive with epoxy groups (including functional groups containing latent active hydrogen that generate active hydrogen upon hydrolysis, etc., and functional groups that exhibit equivalent curing activity). Specific examples include acid anhydride groups, carboxyl groups, amino groups, and phenolic hydroxyl groups. Regarding active hydrogen groups, a carboxyl group (-COOH) or a phenolic hydroxyl group (-OH) is calculated as 1 mole, and an amino group (-NH2) is calculated as 2 moles. If the active hydrogen groups are unclear, the active hydrogen equivalent can be determined by measurement. For example, the active hydrogen equivalent of the curing agent used can be determined by reacting a monoepoxy resin with a known epoxy equivalent, such as phenyl glycidyl ether, with a curing agent with an unknown active hydrogen equivalent and measuring the amount of monoepoxy resin consumed.

[0102] When an epoxy resin is blended, a curing accelerator can be used as needed. Examples of the curing accelerator include imidazoles, tertiary amines, phosphorus compounds such as phosphines, metal compounds, Lewis acids, and amine complex salts. These curing accelerators may be used alone or in combination of two or more.

[0103] The imidazoles are not particularly limited as long as they are compounds having an imidazole skeleton. Examples thereof include alkyl-substituted imidazole compounds such as 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, bis-2-ethyl-4-methylimidazole, 1-methyl-2-ethylimidazole, 2-isopropylimidazole, 2,4-dimethylimidazole, and 2-heptadecylimidazole; and imidazole compounds substituted with a hydrocarbon group containing a ring structure, such as an aryl group or an aralkyl group, such as 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-ethylimidazole, 1-benzyl-2-phenylimidazole, benzimidazole, 2-ethyl-4-methyl-1-(2'-cyanoethyl)imidazole, and 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole.

[0104] Examples of tertiary amines include 2-dimethylaminopyridine, 4-dimethylaminopyridine, 2-(dimethylaminomethyl)phenol, and 1,8-diaza-bicyclo[5.4.0]-7-undecene (DBU).

[0105] Examples of phosphines include triphenylphosphine, tricyclohexylphosphine, triphenylphosphine triphenylborane, and the like.

[0106] An example of the metal compound is tin octoate.

[0107] Examples of amine complex salts include boron trifluoride complexes such as boron trifluoride monoethylamine complex, boron trifluoride diethylamine complex, boron trifluoride isopropylamine complex, boron trifluoride chlorophenylamine complex, boron trifluoride benzylamine complex, boron trifluoride aniline complex, and mixtures thereof.

[0108] Of these curing accelerators, when used for build-up materials or circuit boards, 2-dimethylaminopyridine, 4-dimethylaminopyridine and imidazoles are preferred because of their excellent heat resistance, electrical properties, solder resistance and the like.

[0109] The amount of curing accelerator to be added may be appropriately selected depending on the intended use, but is preferably 0.01 to 15 parts by mass, more preferably 0.01 to 10 parts by mass, more preferably 0.05 to 8 parts by mass, and even more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the epoxy resin component in the resin composition. Use of a curing accelerator can lower the curing temperature and shorten the curing time.

[0110] Resin compositions in which an acrylic ester resin as a curable resin component is cured with a radical polymerization initiator include thermosetting resin compositions and photocurable resin compositions of (meth)acrylate compounds. The (meth)acrylate compound is an acrylate having at least one (meth)acryloyl group in the molecule, which is used as a viscosity adjuster or curing component. It is preferable that some of the (meth)acrylate compounds have two or more (meth)acryloyl groups. In this case, the resin composition contains a (meth)acrylate compound and a thermal polymerization initiator, a photopolymerization initiator, or both as essential components.

[0111] Examples of these (meth)acrylate compounds include monofunctional (meth)acrylic acid esters, polyfunctional (meth)acrylates, urethane (meth)acrylates, epoxy acrylates, etc. These (meth)acrylate compounds may be used alone or in combination of two or more.

[0112] Examples of monofunctional (meth)acrylic acid esters include isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, acryloylmorpholine, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, cyclohexane-1,4-dimethanol mono(meth)acrylate, tetramethylsilyl (meth)acrylate, methyl ... Examples of such acrylates include hydrofurofuryl (meth)acrylate, phenoxyethyl (meth)acrylate, phenyl polyethoxy (meth)acrylate, 2-hydroxy-3-phenyloxypropyl (meth)acrylate, o-phenylphenol monoethoxy (meth)acrylate, o-phenylphenol polyethoxy (meth)acrylate, p-cumylphenoxyethyl (meth)acrylate, isobornyl (meth)acrylate, tribromophenyloxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate.

[0113] Examples of polyfunctional (meth)acrylates include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, bisphenol A polyethoxydi(meth)acrylate, bisphenol A polypropoxydi(meth)acrylate, bisphenol F polyethoxydi(meth)acrylate, ethylene glycol di(meth)acrylate, trimethylolpropane trioxyethyl(meth)acrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate. acrylate, polyethylene glycol di(meth)acrylate, tris(acryloxyethyl)isocyanurate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, tripentaerythritol hexa(meth)acrylate, tripentaerythritol penta(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane polyethoxy tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, cyclohexanedimethanol di(meth)acrylate, and dimethyloltricyclodecane di(meth)acrylate.

[0114] Urethane (meth)acrylates can be obtained by reacting a polyol compound with a polyisocyanate compound and then reacting the resulting compound with a (meth)acrylate, while epoxy acrylates can be obtained by reacting an epoxy compound with a (meth)acrylate.

[0115] Furthermore, compounds that can be used as polymerization initiators for (meth)acrylate compounds are not particularly limited as long as they generate radicals by means of heating, irradiation with active energy rays, or the like. For example, when curing is performed by heating, any of the polymerization initiators that can be used in conventional radical thermal polymerization, such as azo-based initiators (e.g., azobisisobutyronitrile, benzoyl peroxide, etc.) or peroxide-based initiators, can be used. Furthermore, when radical polymerization is performed by photoradical polymerization, any of the initiators that can be used in conventional photoradical polymerization, such as benzoins, acetophenones, anthraquinones, thioxanthones, ketals, benzophenones, and phosphine oxides, can be used. These polymerization photoinitiators may be used alone or in combination with two or more of them. Furthermore, the photoradical polymerization initiator may be used in combination with an accelerator, such as a tertiary amine compound or N,N-dimethylaminobenzoic acid ethyl ester.

[0116] In addition, the resin composition of the present invention may contain an organic solvent or a reactive diluent for adjusting viscosity. These organic solvents or reactive diluents may be used alone or in combination of two or more.

[0117] Examples of organic solvents include amides such as N,N-dimethylformamide and N,N-dimethylacetamide, ethers such as dioxane, tetrahydrofuran, ethylene glycol monomethyl ether, dimethoxydiethylene glycol, ethylene glycol diethyl ether, diethylene glycol diethyl ether and triethylene glycol dimethyl ether, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, alcohols such as methanol, ethanol, 1-methoxy-2-propanol, 2-ethyl-1-hexanol, benzyl alcohol, ethylene glycol, propylene glycol, butyl diglycol and pine oil, and ethanol acetate. Examples of the solvent include acetate esters such as butyl acetate, butyl acetate, methoxybutyl acetate, methyl cellosolve acetate, cellosolve acetate, ethyl diglycol acetate, propylene glycol monomethyl ether acetate, carbitol acetate, and benzyl alcohol acetate; benzoate esters such as methyl benzoate and ethyl benzoate; cellosolves such as methyl cellosolve, cellosolve, and butyl cellosolve; carbitols such as methyl carbitol, carbitol, and butyl carbitol; aromatic hydrocarbons such as benzene, toluene, and xylene; sulfoxides such as dimethyl sulfoxide; alkanes such as hexane and cyclohexane; acetonitrile; and N-methylpyrrolidone.

[0118] Examples of reactive diluents include monofunctional glycidyl ethers such as allyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, and tolyl glycidyl ether; bifunctional glycidyl ethers such as resorcinol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, and propylene glycol diglycidyl ether; polyfunctional glycidyl ethers such as glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, trimethylolethane polyglycidyl ether, and pentaerythritol polyglycidyl ether; glycidyl esters such as neodecanoic acid glycidyl ester; and glycidyl amines such as phenyl diglycidyl amine and tolyl diglycidyl amine.

[0119] These organic solvents or reactive diluents are preferably used in an amount of 90% by mass or less as nonvolatile matter, and the appropriate type and amount are appropriately selected depending on the application. For example, for printed wiring board applications, polar solvents with a boiling point of 160°C or less, such as methyl ethyl ketone, acetone, and 1-methoxy-2-propanol, are preferred, and the amount used is preferably 40 to 80% by mass as nonvolatile matter. For adhesive film applications, for example, ketones, acetate esters, carbitols, aromatic hydrocarbons, dimethylformamide, dimethylacetamide, and N-methylpyrrolidone are preferred, and the amount used is preferably 30 to 60% by mass as nonvolatile matter.

[0120] In order to improve the flame retardancy of the resulting cured product, various known flame retardants can be used in the resin composition of the present invention, as long as the reliability is not reduced. Usable flame retardants include, for example, halogen-based flame retardants, phosphorus-based flame retardants, nitrogen-based flame retardants, silicone-based flame retardants, inorganic flame retardants, and organic metal salt-based flame retardants. From an environmental perspective, halogen-free flame retardants are preferred, and phosphorus-based flame retardants are particularly preferred. These flame retardants may be used alone, or two or more of the same type of flame retardants may be used in combination, or different types of flame retardants may be used in combination.

[0121] Phosphorus-based flame retardants are divided into two types: additive-based phosphorus-based flame retardants (phosphorus-containing additives) and reactive phosphorus compounds, and reactive phosphorus compounds are further divided into phosphorus-containing epoxy resins and phosphorus-containing curing agents. When comparing additive-based phosphorus-based flame retardants with reactive phosphorus compounds, reactive phosphorus compounds have a greater flame retardant effect because they do not bleed out during curing and have good compatibility, making it preferable to use reactive phosphorus compounds.

[0122] The phosphorus-containing additive may be either an inorganic phosphorus compound or an organic phosphorus compound, including, but not limited to, red phosphorus, ammonium phosphates such as monoammonium phosphate, diammonium phosphate, triammonium phosphate, and ammonium polyphosphate, and inorganic nitrogen-containing phosphorus compounds such as phosphoric acid amide.

[0123] Furthermore, it is preferable that the red phosphorus has been subjected to a surface treatment for the purpose of preventing hydrolysis and the like. Examples of the surface treatment method include, but are not limited to, (1) a method of coating with an inorganic compound such as magnesium hydroxide, aluminum hydroxide, zinc hydroxide, titanium hydroxide, bismuth oxide, bismuth hydroxide, bismuth nitrate, or a mixture thereof; (2) a method of coating with a mixture of an inorganic compound such as magnesium hydroxide, aluminum hydroxide, zinc hydroxide, titanium hydroxide, and a thermosetting resin such as a phenolic resin; and (3) a method of doubly coating with a thermosetting resin such as a phenolic resin on top of a coating of an inorganic compound such as magnesium hydroxide, aluminum hydroxide, zinc hydroxide, titanium hydroxide, etc.

[0124] Examples of organic phosphorus compounds include phosphate ester compounds (e.g., methyl acid phosphate, ethyl acid phosphate, isopropyl acid phosphate, dibutyl phosphate, monobutyl phosphate, butoxyethyl acid phosphate, 2-ethylhexyl acid phosphate, bis(2-ethylhexyl) phosphate, monoisodecyl acid phosphate, lauryl acid phosphate, tridecyl acid phosphate, oleyl acid phosphate, tetracosyl acid phosphate, stearyl acid phosphate, isostearyl acid phosphate, butyl pyrophosphate, ethyl general-purpose organophosphorus compounds such as ethylene glycol acid phosphate, (2-hydroxyethyl) methacrylate acid phosphate, etc., condensed phosphate esters (e.g., PX-200 (manufactured by Daihachi Chemical Industry Co., Ltd.)), phosphonic acid compounds, phosphinic acid compounds, phosphine oxide compounds (e.g., diphenylphosphine oxide, triphenylphosphine oxide), phosphorane compounds (e.g., triphenyl(9H-fluoren-9-ylidene)phosphorane), nitrogen-containing organophosphorus compounds (e.g., SPS-100, SPB-100, SPE-100 (manufactured by Otsuka Chemical Co., Ltd.)), and metal phosphinates (e.g., EXOLIT OP1230, OP1240, OP930, OP935 (all manufactured by Clariant), etc.), phosphorus compounds having an active hydrogen group directly bonded to the phosphorus atom (e.g., 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (hereinafter abbreviated as DOPO), diphenylphosphine oxide, etc.) and phosphorus-containing phenolic compounds (e.g., 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, (hereinafter abbreviated as DOPO-HQ), 10-(2,7-dihydroxy-1-naphthyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(1,4-dihydroxy-2-naphthyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide (hereinafter abbreviated as DOPO-NQ), diphenylphosphinylhydroquinone, diphenylphosphinyl-1,4-dioxynaphthalene, 1,4-cyclooctylenephosphinyl-1,Examples of suitable organic phosphorus compounds include, but are not limited to, organic phosphorus compounds such as 1,4-phenyldiol, 1,5-cyclooctylenephosphinyl-1,4-phenyldiol, and the like.

[0125] Further examples include phosphorus-containing epoxy resins and phosphorus-containing curing agents, which are derivatives obtained by reacting the above-mentioned organic phosphorus compounds with compounds such as epoxy resins and phenolic resins. As the reactive phosphorus compounds used in these, the above-mentioned phosphorus compounds having an active hydrogen group directly bonded to the phosphorus atom and phosphorus-containing phenols are preferred, and DOPO, DOPO-HQ, DOPO-NQ, etc. are more preferred in terms of ease of availability.

[0126] Examples of phosphorus-containing epoxy resins include, but are not limited to, Epotohto FX-305, FX-289B, FX-1225, TX-1320A, and TX-1328 (all manufactured by Nippon Steel Chemical & Material Co., Ltd.).

[0127] The epoxy equivalent of the phosphorus-containing epoxy resin is preferably 200 to 800, more preferably 300 to 780, and even more preferably 400 to 760. The phosphorus content of the phosphorus-containing epoxy resin is preferably 0.5 to 6 mass%, more preferably 2 to 5.5 mass%, and even more preferably 3 to 5 mass%.

[0128] In addition to the phosphorus-containing phenols mentioned above, phosphorus-containing curing agents include those disclosed in JP-A-2008-501063 and Japanese Patent No. 4548547, for example, by reacting DOPO with aldehydes and a phenolic compound to obtain a phosphorus-containing phenolic compound. In this case, the phosphorus-based compound is incorporated into the molecule by condensation addition to the aromatic ring of the phenolic compound via the aldehyde. Furthermore, by a production method disclosed in JP-A-2013-185002, a phosphorus-containing active ester compound can be obtained from the phosphorus-containing phenolic compound by further reacting it with an aromatic carboxylic acid. Furthermore, a phosphorus-containing benzo compound can be obtained by a production method disclosed in JP-A-2008 / 010429.

[0129] The phosphorus content of the phosphorus-containing curing agent is preferably from 0.5 to 12 mass %, more preferably from 2 to 11 mass %, and even more preferably from 4 to 10 mass %.

[0130] The amount of the phosphorus compound to be added is appropriately selected depending on the type of phosphorus compound, the components of the resin composition, and the desired level of flame retardancy. When the phosphorus compound is a reactive phosphorus compound, i.e., a phosphorus-containing epoxy resin or a phosphorus-containing curing agent, the phosphorus content relative to the solid content (non-volatile content) in the resin composition is preferably 0.2 to 6 mass%, more preferably 0.4 to 4 mass%, even more preferably 0.5 to 3.5 mass%, and particularly preferably 0.6 to 3 mass%. If the phosphorus content is too low, it may be difficult to ensure flame retardancy, and if it is too high, it may have a negative effect on heat resistance.

[0131] When a phosphorus-based flame retardant is used, it may be used in combination with an auxiliary flame retardant such as hydrotalcite, magnesium hydroxide, a boron compound, zirconium oxide, calcium carbonate, or zinc molybdate.

[0132] Examples of nitrogen-based flame retardants include triazine compounds, cyanuric acid compounds, isocyanuric acid compounds, and phenothiazines, with triazine compounds, cyanuric acid compounds, and isocyanuric acid compounds being preferred. The amount of nitrogen-based flame retardant to be added is selected appropriately depending on the type of nitrogen-based flame retardant, the other components of the resin composition, and the desired level of flame retardancy. For example, it is preferably added in the range of 0.05 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass, per 100 parts by mass of solids (non-volatile content) in the resin composition. Furthermore, when using a nitrogen-based flame retardant, a metal hydroxide, a molybdenum compound, or the like may be used in combination.

[0133] Examples of triazine compounds include melamine, acetoguanamine, benzoguanamine, melon [2,4,6-tris(cyanoamino)-1,3,5-triazine], melam [4,4'-iminobis(1,3,5-triazine-2,6-diamine)], ethylenedimelamine, melamine polyphosphate, triguanamine, and the like; as well as aminotriazine sulfate compounds such as guanylmelamine sulfate, melem sulfate, and melam sulfate; aminotriazine-modified phenolic resins (e.g., LA-7052 (manufactured by DIC Corporation)); and aminotriazine-modified phenolic resins further modified with tung oil, isomerized linseed oil, or the like, but are not limited to these.

[0134] Examples of cyanuric acid compounds include, but are not limited to, cyanuric acid and melamine cyanurate.

[0135] The silicone flame retardant can be any organic compound containing silicon atoms, and examples thereof include, but are not limited to, silicone oil, silicone rubber, and silicone resin. The amount of silicone flame retardant to be added is selected appropriately depending on the type of silicone flame retardant, the other components of the resin composition, and the desired level of flame retardancy. For example, it is preferable to add 0.05 to 20 parts by mass of the silicone flame retardant to 100 parts by mass of the solids (non-volatile content) in the resin composition. When using a silicone flame retardant, a molybdenum compound, alumina, etc. may also be used in combination.

[0136] Examples of inorganic flame retardants include, but are not limited to, metal hydroxides, metal oxides, metal carbonate compounds, metal powders, boron compounds, low-melting-point glass, etc. The amount of inorganic flame retardant to be added is selected appropriately depending on the type of inorganic flame retardant, the other components of the resin composition, and the desired level of flame retardancy, but it is preferably added in an amount of 0.05 to 20 parts by mass, and more preferably 0.5 to 15 parts by mass, per 100 parts by mass of the solid content (non-volatile content) in the composition.

[0137] Examples of metal hydroxides include, but are not limited to, aluminum hydroxide, magnesium hydroxide, dolomite, hydrotalcite, boehmite, calcium hydroxide, barium hydroxide, and zirconium hydroxide.

[0138] Examples of metal oxides include, but are not limited to, zinc molybdate, molybdenum trioxide, zinc stannate, tin oxide, aluminum oxide, iron oxide, titanium oxide, manganese oxide, zirconium oxide, zinc oxide, molybdenum oxide, cobalt oxide, bismuth oxide, chromium oxide, nickel oxide, copper oxide, and tungsten oxide.

[0139] Examples of metal carbonate compounds include, but are not limited to, zinc carbonate, magnesium carbonate, calcium carbonate, barium carbonate, basic magnesium carbonate, aluminum carbonate, iron carbonate, cobalt carbonate, and titanium carbonate.

[0140] Examples of metal powders include, but are not limited to, aluminum, iron, titanium, manganese, zinc, molybdenum, cobalt, bismuth, chromium, nickel, copper, tungsten, and tin.

[0141] Examples of boron compounds include, but are not limited to, zinc borate, zinc metaborate, barium metaborate, boric acid, and borax.

[0142] Examples of low-melting point glasses include, but are not limited to, hydrated glasses, SiO2-MgO-H2O, PbO-B2O3-based, ZnO-P2O5-MgO-based, P2O5-B2O3-PbO-MgO-based, PSn-OF-based, PbO-V2O5-TeO2-based, Al2O3-H2O-based, and lead borosilicate-based glass compounds.

[0143] The amount of inorganic flame retardant to be added is selected appropriately depending on the type of inorganic flame retardant, the other components of the resin composition, and the desired level of flame retardancy. For example, it is preferable to add it in an amount of 0.05 to 20 parts by mass, and particularly preferably 0.5 to 15 parts by mass, per 100 parts by mass of the solid content (non-volatile content) in the composition.

[0144] Examples of organometallic salt flame retardants include, but are not limited to, ferrocene, acetylacetonate metal complexes, organometallic carbonyl compounds, organic cobalt salt compounds, organic sulfonic acid metal salts, and compounds in which a metal atom is ionic- or coordinate-bonded to an aromatic compound or a heterocyclic compound. The amount of the organometallic salt flame retardant to be added is appropriately selected depending on the type of organometallic salt flame retardant, the other components of the resin composition, and the desired level of flame retardancy. For example, it is preferable to add the organometallic salt flame retardant in an amount of 0.005 to 10 parts by mass per 100 parts by mass of the solids (nonvolatiles) in the resin composition.

[0145] Examples of halogen-based flame retardants include bromine compounds and chlorine compounds, but chlorine compounds are not preferred due to toxicity issues. The amount of halogen-based flame retardant to be added is appropriately selected depending on the type of halogen-based flame retardant, other components of the resin composition, and the desired level of flame retardancy. For example, the halogen content is preferably 5 to 15 mass% relative to the solid content (non-volatile content) in the resin composition.

[0146] Furthermore, when a halogen-based flame retardant is used as the flame retardant, the following may be used in combination as a flame retardant aid: antimony compounds such as antimony trioxide, antimony tetraoxide, and antimony pentoxide; tin compounds such as tin oxide and tin hydroxide; molybdenum compounds such as molybdenum oxide and ammonium molybdate; zirconium compounds such as zirconium oxide and zirconium hydroxide; boron compounds such as zinc borate and barium metaborate; silicon compounds such as silicone oil, silane coupling agents, and high-molecular-weight silicone; and chlorinated polyethylene.

[0147] Examples of bromine compounds include, but are not limited to, p-dibromobenzene, pentabromodiphenyl ether, octabromodiphenyl ether, tetradecabromo-p-diphenoxybenzene, decabromodiphenyl ether, tetrabromobisphenol A, hexabromocyclododecane, hexabromobenzene, 2,2'-ethylenebis(4,5,6,7-tetrabromoisoindoline-1,3-dione (e.g., SAYTEX BT-93 (manufactured by Albemarle)), ethane-1,2-bis(pentabromophenyl) (e.g., SAYTEX 8010 (manufactured by Albemarle)), and brominated epoxy oligomers (e.g., SR-T1000, SR-T2000 (both manufactured by Sakamoto Pharmaceutical Co., Ltd.)).

[0148] Furthermore, other additives such as fillers, thermoplastic resins, coupling agents, antioxidants, release agents, antifoaming agents, emulsifiers, thixotropy-imparting agents, smoothing agents, and pigments may be blended into the resin composition as needed, within limits that do not impair the properties of the composition.

[0149] Examples of fillers include inorganic fillers such as fused silica, crystalline silica, alumina, silicon nitride, boron nitride, aluminum nitride, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, boehmite, talc, mica, clay, calcium carbonate, magnesium carbonate, barium carbonate, zinc oxide, titanium oxide, magnesium oxide, magnesium silicate, calcium silicate, zirconium silicate, barium sulfate, and carbon; fibrous fillers such as carbon fiber, glass fiber, alumina fiber, silica alumina fiber, silicon carbide fiber, polyester fiber, cellulose fiber, aramid fiber, and ceramic fiber; and fine particle rubber.

[0150] Among these, those that do not decompose or dissolve in oxidizing compounds, such as aqueous solutions of permanganate, used in surface roughening treatment of cured products are preferred. Fused silica and crystalline silica are particularly preferred because they are easy to obtain as fine particles. Fused silica is also preferred when the filler content is particularly high. While either crushed or spherical fused silica can be used, it is more preferable to primarily use spherical silica in order to suppress an increase in the melt viscosity of the molding material while increasing the fused silica content. Furthermore, to increase the amount of spherical silica, it is preferable to appropriately adjust the particle size distribution of the spherical silica. The filler may be treated with a silane coupling agent or an organic acid such as stearic acid. Common reasons for using fillers include improving the impact resistance and reducing the linear expansion of the cured product. Furthermore, when metal hydroxides such as aluminum hydroxide, boehmite, and magnesium hydroxide are used, they act as flame retardant aids, improving flame retardancy. When improving thermal conductivity, alumina, silicon nitride, boron nitride, aluminum nitride, fused silica, and crystalline silica are preferred, and alumina, boron nitride, fused silica, and crystalline silica are more preferred.When used in applications such as conductive pastes, conductive fillers such as silver powder and copper powder can be used.

[0151] The amount of filler blended is preferably high, taking into consideration the low linear expansion and flame retardancy of the cured product. It is preferably 1 to 98% by mass, more preferably 3 to 90% by mass, even more preferably 5 to 80% by mass, and particularly preferably 10 to 60% by mass, based on the total solids content of the resin composition. If the blended amount is too high, the adhesiveness required for laminated plate applications may be reduced, and the cured product may become brittle, making it difficult to obtain sufficient mechanical properties. If the blended amount is too low, the effects of blending the filler, such as improving the impact resistance of the cured product, may not be achieved.

[0152] Furthermore, if the particle size of the inorganic filler is too large, voids tend to remain in the cured product, while if it is too small, it tends to aggregate and become less dispersible. The average particle size is preferably 0.01 to 5 μm, more preferably 0.05 to 1.5 μm, and even more preferably 0.1 to 1 μm. If the average particle size of the inorganic filler is within this range, the resin composition can maintain good fluidity. The average particle size can be measured using a particle size distribution analyzer.

[0153] The resin composition of the present invention may contain a thermoplastic resin other than the phenoxy resin of the present invention. Examples of thermoplastic resins include phenoxy resins other than those of the present invention, polyurethane resins, polyester resins, polyethylene resins, polypropylene resins, polystyrene resins, ABS resins, AS resins, vinyl chloride resins, polyvinyl acetate resins, polymethyl methacrylate resins, polycarbonate resins, polyacetal resins, cyclic polyolefin resins, polyamide resins, thermoplastic polyimide resins, polyamideimide resins, polytetrafluoroethylene resins, polyetherimide resins, polyphenylene ether resins, modified polyphenylene ether resins, polyethersulfone resins, polysulfone resins, polyetheretherketone resins, polyphenylene sulfide resins, and polyvinyl formal resins. From the viewpoint of compatibility, phenoxy resins other than those of the present invention are preferred, and from the viewpoint of low dielectric properties, polyphenylene ether resins and modified polyphenylene ether resins are preferred.

[0154] A coupling agent may be blended into the resin composition of the present invention. By blending a coupling agent, adhesion to the substrate and adhesion between the matrix resin and the inorganic filler can be improved. Examples of coupling agents include silane coupling agents and titanate coupling agents. These coupling agents may be used alone or in combination of two or more. The amount of coupling agent blended is preferably about 0.1 to 2.0 mass% based on the total solid content in the resin composition. If the amount of coupling agent blended is too small, the effect of improving adhesion between the matrix resin and the inorganic filler due to the blending of the coupling agent cannot be fully obtained. On the other hand, if the amount of coupling agent blended is too large, the coupling agent may bleed out from the resulting cured product.

[0155] Examples of the silane coupling agent include epoxy silanes such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; amino silanes such as γ-aminopropyltriethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane, γ-aminopropyltrimethoxysilane, and γ-ureidopropyltriethoxysilane; mercapto silanes such as 3-mercaptopropyltrimethoxysilane; vinyl silanes such as p-styryltrimethoxysilane, vinyltrichlorosilane, vinyltris(β-methoxyethoxy)silane, vinyltrimethoxysilane, vinyltriethoxysilane, and γ-methacryloxypropyltrimethoxysilane; and polymeric epoxy, amino, and vinyl silanes.

[0156] Examples of titanate coupling agents include isopropyl triisostearoyl titanate, isopropyl tri(N-aminoethyl aminoethyl) titanate, diisopropyl bis(dioctyl phosphate) titanate, tetraisopropyl bis(dioctyl phosphite) titanate, tetraoctyl bis(ditridecyl phosphite) titanate, tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl)phosphite titanate, bis(dioctyl pyrophosphate)oxyacetate titanate, and bis(dioctyl pyrophosphate)ethylene titanate.

[0157] Examples of other additives include organic pigments such as quinacridone, azo, and phthalocyanine pigments, inorganic pigments such as titanium oxide, metal foil pigments, and anti-rust pigments, ultraviolet absorbers such as hindered amine, benzotriazole, and benzophenone, antioxidants such as hindered phenol, phosphorus, sulfur, and hydrazide, release agents such as stearic acid, palmitic acid, zinc stearate, and calcium stearate, leveling agents, rheology control agents, pigment dispersants, anti-cracking agents, and anti-foaming agents. The amount of these other additives added is preferably 0.01 to 20% by mass based on the total solid content of the resin composition.

[0158] The resin composition of the present invention can be obtained by uniformly mixing the above components. Resin compositions containing a phenoxy resin, a curable resin component, and, if necessary, various additives can be easily cured using methods similar to those known in the art. Examples of cured products include laminates, cast products, molded products, adhesive layers, insulating layers, and films. Methods for obtaining cured products include those used for known resin compositions, such as casting, injection, potting, dipping, drip coating, transfer molding, and compression molding, as well as laminating resin sheets, resin-coated copper foils, prepregs, and curing them under heat and pressure to form laminates. The curing method for the resin composition varies depending on the components and their amounts in the resin composition, but typically involves a curing temperature of 80 to 300°C and a curing time of 10 to 360 minutes. This heating is preferably carried out in two stages: primary heating at 80 to 180°C for 10 to 90 minutes, followed by secondary heating at 120 to 200°C for 60 to 150 minutes. Furthermore, for formulations whose glass transition temperature (Tg) exceeds the secondary heating temperature, tertiary heating at 150 to 280°C for 60 to 120 minutes is also preferred. Such secondary and tertiary heating can reduce curing defects. When producing semi-cured resin products such as resin sheets, resin-coated copper foils, and prepregs, the curing reaction of the resin composition is typically allowed to proceed to an extent that the shape can be maintained by heating or the like. When the resin composition contains a solvent, most of the solvent is typically removed by techniques such as heating, reduced pressure, and air drying. However, up to 5% by mass of the solvent may remain in the semi-cured resin product.

[0159] The resin composition can be used in a variety of fields, including as a circuit board material, sealing material, casting material, conductive paste, adhesive, insulating material, etc., and is particularly useful in the electrical and electronic fields as an insulating casting material, laminate material, sealing material, etc. Examples of applications include printed wiring boards, flexible wiring boards, laminates for electrical and electronic circuits such as capacitors, resin-coated metal foils, adhesives such as film adhesives and liquid adhesives, semiconductor sealing materials, underfill materials, interchip fills for 3D-LSI, insulating materials for circuit boards, insulating sheets, prepregs, heat dissipation substrates, and resist inks, but are not limited to these.

[0160] Among these various applications, in applications such as printed wiring board materials, insulating materials for circuit boards, and adhesive films for build-up, they can be used as insulating materials for so-called electronic component-embedded substrates, in which passive components such as capacitors and active components such as IC chips are embedded in the substrate. Among these, due to their properties such as high flame retardancy, high heat resistance, and solvent solubility, they are preferably used as printed wiring board materials, resin compositions for flexible wiring boards, materials for circuit boards (laminates) such as interlayer insulating materials for build-up boards, and semiconductor encapsulation materials.

[0161] When the resin composition is formed into a plate such as a laminate, the filler to be used is preferably fibrous in terms of dimensional stability, bending strength, etc., and glass cloth, glass mat, and glass roving cloth are more preferred.

[0162] The resin composition can be impregnated into a fibrous reinforcing substrate to produce a prepreg for use in printed wiring boards, etc. Examples of the fibrous reinforcing substrate that can be used include, but are not limited to, inorganic fibers such as glass, and woven or nonwoven fabrics of organic fibers such as polyester resin, polyamine resin, polyacrylic resin, polyimide resin, and aromatic polyamide resin.

[0163] The method for producing a prepreg from the resin composition is not particularly limited. For example, a resin varnish containing the organic solvent is prepared by further blending an organic solvent to an appropriate viscosity, and the resin varnish is then impregnated into the fibrous substrate. The resin varnish is then heated and dried to semi-cure (B-stage) the resin component. The heating temperature is preferably 50 to 200°C, more preferably 100 to 170°C, depending on the type of organic solvent used. The heating time is adjusted depending on the type of organic solvent used and the curability of the prepreg, and is preferably 1 to 40 minutes, more preferably 3 to 20 minutes. The mass ratio of the resin composition to the reinforcing substrate used is not particularly limited, but it is generally preferable to adjust the resin content in the prepreg to 20 to 80% by mass.

[0164] The resin composition of the present invention can be formed into a sheet or film for use. In this case, it can be formed into a sheet or film using a conventionally known method. The method for producing a resin sheet is not particularly limited, but examples include (a) an extrusion molding method in which the resin composition is kneaded in an extruder, extruded, and formed into a sheet using a T-die or circular die, (b) a casting molding method in which the resin composition is dissolved or dispersed in a solvent such as an organic solvent, and then cast to form a sheet, and (c) other conventionally known sheet molding methods. The thickness (μm) of the resin sheet is not particularly limited, but is preferably 10 to 300, more preferably 25 to 200, and even more preferably 40 to 180. When used in a build-up method, the thickness of the resin sheet is particularly preferably 40 to 90 μm. A thickness of 10 μm or more ensures insulation, while a thickness of 300 μm or less prevents the circuit distance between electrodes from becoming unnecessarily long. The solvent content of the resin sheet is not particularly limited, but is preferably 0.01 to 5 mass% of the total resin composition. If the solvent content in the film is 0.01% by mass or more relative to the total resin composition, adhesion and bonding are easily achieved when laminating to a circuit board, and if it is 5% by mass or less, flatness after heat curing is easily achieved.

[0165] A more specific method for producing an adhesive sheet is to apply a varnish-like resin composition containing the organic solvent to a supporting base film that is insoluble in organic solvents using a coater such as a reverse roll coater, comma coater, or die coater, and then heat and dry the film to bring the resin component to a B-stage. If necessary, a separate supporting base film is placed on the coated surface (adhesive layer) as a protective film, and the resulting film is dried to obtain an adhesive sheet having release layers on both sides of the adhesive layer.

[0166] Examples of the supporting base film include metal foils such as copper foil, polyolefin films such as polyethylene film and polypropylene film, polyester films such as polyethylene terephthalate film, polycarbonate film, silicone film, and polyimide film. Among these, polyethylene terephthalate film is preferred because it is free of defects such as lumps, has excellent dimensional accuracy, and is cost-effective. Metal foils, particularly copper foils, are also preferred because they are easy to form into multilayer laminates. The thickness of the supporting base film is not particularly limited, but is preferably 10 to 150 μm, more preferably 25 to 50 μm, because it provides strength as a support and is less likely to cause lamination defects.

[0167] The thickness of the protective film is not particularly limited, but is generally 5 to 50 μm. It is preferable to preliminarily treat the surface with a release agent to facilitate peeling of the molded adhesive sheet. The thickness of the applied resin varnish, after drying, is preferably 5 to 200 μm, more preferably 5 to 100 μm.

[0168] The heating temperature depends on the type of organic solvent used and is preferably 50 to 200° C., more preferably 100 to 170° C. The heating time is adjusted depending on the type of organic solvent used and the curing property of the prepreg, and is preferably 1 to 40 minutes, more preferably 3 to 20 minutes.

[0169] The resin sheet obtained in this manner usually becomes an insulating adhesive sheet having insulating properties, but a conductive adhesive sheet can also be obtained by mixing conductive metal or metal-coated fine particles into the resin composition. The supporting base film is peeled off after laminating it to a circuit board or after heat curing to form an insulating layer. Peeling off the supporting base film after heat curing the adhesive sheet can prevent the adhesion of dust and other foreign matter during the curing process. Here, the insulating adhesive sheet also serves as an insulating sheet.

[0170] The resin-coated metal foil obtained from the resin composition of the present invention will now be described. Examples of usable metal foils include simple, alloy, and composite metal foils of copper, aluminum, brass, nickel, and the like. It is preferable to use a metal foil with a thickness of 9 to 70 μm. The method for producing the resin-coated metal foil from the resin composition and metal foil of the present invention is not particularly limited. For example, the resin-coated metal foil can be obtained by applying a resin varnish, prepared by adjusting the viscosity of the resin composition with a solvent, to one side of the metal foil using a roll coater or the like, followed by heating and drying to semi-cure (B-stage) the resin component to form a resin layer. To semi-cure the resin component, for example, heating and drying can be performed at 100 to 200°C for 1 to 40 minutes. The thickness of the resin portion of the resin-coated metal foil is preferably 5 to 110 μm.

[0171] In addition, to harden the prepreg or insulating adhesive sheet, a method for hardening a laminate generally used in manufacturing a printed wiring board can be used, but is not limited to this. For example, when forming a laminate using a prepreg, one or more prepregs are stacked, and metal foil is placed on one or both sides to form a laminate, and this laminate is then pressurized and heated to harden and integrate the prepregs to obtain a laminate. Here, the metal foil can be a single metal foil, an alloy foil, or a composite metal foil of copper, aluminum, brass, nickel, etc.

[0172] The conditions for heating and pressing the laminate can be adjusted appropriately to ensure curing of the resin composition. However, if the pressure is too low, air bubbles may remain inside the resulting laminate, resulting in reduced electrical properties. Therefore, it is preferable to pressurize the laminate under conditions that satisfy moldability. The heating temperature is preferably 160 to 250°C, more preferably 170 to 220°C. The pressure is preferably 0.5 to 10 MPa, more preferably 1 to 5 MPa. The heating and pressing time is preferably 10 minutes to 4 hours, more preferably 40 minutes to 3 hours. If the heating temperature is too low, the curing reaction may not proceed sufficiently, while if the pressure is too high, thermal decomposition of the cured product may occur. If the pressure is too low, air bubbles may remain inside the resulting laminate, resulting in reduced electrical properties. If the pressure is too high, the resin may flow before curing, preventing the desired thickness from being obtained. Furthermore, if the heating and pressing time is too short, the curing reaction may not proceed sufficiently, while if it is too long, thermal decomposition of the cured product may occur.

[0173] Furthermore, a multilayer board can be produced using the single-layer laminate thus obtained as an inner layer material. In this case, a circuit is first formed on the laminate by an additive method, a subtractive method, or the like, and the circuit surface is then blackened with an acid solution to obtain an inner layer material. An insulating layer is formed on one or both circuit-forming surfaces of this inner layer material using a prepreg, a resin sheet, an insulating adhesive sheet, or a resin-coated metal foil, and a conductor layer is formed on the surface of the insulating layer to form a multilayer board.

[0174] Furthermore, when forming an insulating layer using prepreg, one or more prepreg sheets are placed on the circuit-forming surface of the inner layer material, and a metal foil is placed on the outer surface to form a laminate. This laminate is then heated and pressurized to form an integral molding, thereby forming the cured prepreg as an insulating layer and the outer metal foil as a conductor layer. The metal foil can be the same as that used in the laminate used as the inner layer board. The heat and pressure molding can be performed under the same conditions as for molding the inner layer material. The surface of the multilayer laminate thus formed can then be further subjected to via hole formation and circuit formation by an additive or subtractive method to form a printed wiring board. Furthermore, by repeating the above process using this printed wiring board as the inner layer material, further multilayer boards can be formed.

[0175] For example, when forming an insulating layer using an insulating adhesive sheet, a laminate is formed by placing an insulating adhesive sheet on the circuit-forming surfaces of multiple inner layer materials. Alternatively, a laminate is formed by placing an insulating adhesive sheet between the circuit-forming surfaces of the inner layer materials and metal foil. This laminate is then heated and pressurized to form an integral molding, thereby forming the cured insulating adhesive sheet as an insulating layer and forming a multilayer inner layer material. Alternatively, the inner layer material and the metal foil serving as the conductor layer are combined to form the cured insulating adhesive sheet as an insulating layer. Here, the metal foil can be the same as that used in the laminate used as the inner layer material. Furthermore, the heat and pressure molding can be performed under the same conditions as those used to mold the inner layer material.

[0176] Furthermore, when forming an insulating layer by applying a resin composition to a laminate, the resin composition is preferably applied to a thickness of 5 to 100 μm and then heated and dried at 100 to 200°C, preferably 150 to 200°C, for 1 to 120 minutes, preferably 30 to 90 minutes, to form a sheet. This is generally formed by a method known as the casting method. The thickness after drying is preferably 5 to 150 μm, preferably 5 to 80 μm. The viscosity of the resin composition at 25°C is preferably 10 to 40,000 mPa·s, more preferably 200 to 30,000 mPa·s, because this ensures a sufficient film thickness and reduces the occurrence of uneven coating or streaks. A printed wiring board can be formed by further forming via holes and circuits on the surface of the multilayer laminate formed in this manner using an additive or subtractive method. Furthermore, by repeating the above process using this printed wiring board as an inner layer material, further multilayer laminates can be formed.

[0177] The resin composition of the present invention can be used to produce an encapsulant suitable for tape-shaped semiconductor chips, potting liquid encapsulation, underfill, semiconductor interlayer insulating film, etc. For example, semiconductor package molding can be achieved by molding the resin composition using a casting or transfer molding machine, injection molding machine, or the like, and then heating the molded product at 50 to 200°C for 2 to 10 hours.

[0178] To prepare a resin composition for use as a semiconductor encapsulation material, a method may be used in which the resin composition is premixed with compounding agents such as inorganic fillers, and additives such as coupling agents and mold release agents, which are blended as needed, and then the mixture is thoroughly melt-mixed until homogeneous using an extruder, kneader, rolls, etc. In this case, silica is usually used as the inorganic filler, and in this case, the inorganic filler is preferably blended in the resin composition in a proportion of 70 to 95 mass%.

[0179] When the resin composition thus obtained is used as a tape-shaped sealant, it can be heated to prepare a semi-cured sheet, which is then made into a sealant tape, and the sealant tape is placed on a semiconductor chip, heated to 100 to 150° C. to soften and mold the sheet, and then completely cured at 170 to 250° C. When the resin composition is used as a potting-type liquid sealant, the resin composition obtained can be dissolved in a solvent as needed, applied to a semiconductor chip or an electronic component, and directly cured.

[0180] The resin composition of the present invention can also be used as a resist ink. In this case, a vinyl monomer having an ethylenically unsaturated double bond and a cationic polymerization catalyst as a curing agent are blended with the resin composition, and a pigment, talc, and a filler are further added to form a resist ink composition, which is then applied to a printed circuit board by screen printing to form a cured resist ink. The curing temperature in this case is preferably in the range of about 20 to 250°C.

[0181] The resin composition of the present invention was prepared, and the cured product was evaluated by heat curing. Despite the low carbon content, the cured product exhibited good flame retardancy. This indicates that the material has excellent tracking resistance. Therefore, it is useful as a substrate material for mounting heat-generating components such as LEDs. [Example]

[0182] The present invention will be specifically explained below with reference to examples and comparative examples, but the present invention is not limited to these as long as it does not depart from the gist of the invention. Unless otherwise specified, parts represent "parts by mass" and % represents "% by mass". Analytical and measurement methods are shown below.

[0183] (1) Epoxy equivalent: Measurements were carried out in accordance with JIS K7236, and the unit was expressed in "g / eq." Specifically, a potentiometric titrator was used, methyl ethyl ketone was used as the solvent, tetraethylammonium bromide acetate solution was added, and a 0.1 mol / L perchloric acid-acetic acid solution was used. For solvent-diluted products (resin varnishes), the solid content was calculated from the nonvolatile content.

[0184] (2) Hydroxyl equivalent: Measurements were carried out in accordance with JIS K0070 standard, and the unit was expressed as "g / eq." Unless otherwise specified, the hydroxyl group equivalent of the phenolic resin means the phenolic hydroxyl group equivalent.

[0185] (3) Nonvolatile content: Measurements were made in accordance with JIS K7235. The drying temperature was 200°C and the drying time was 60 minutes.

[0186] (4) Weight average molecular weight (Mw): The results were obtained by GPC measurement. Specifically, the main body (HLC-8220GPC, manufactured by Tosoh Corporation) was fitted with a column (TSKgel G4000H, manufactured by Tosoh Corporation). XL , TSKgelG3000H XL , TSKgelG2000H XL The column temperature was 40°C. Tetrahydrofuran (THF) was used as the eluent at a flow rate of 1 mL / min, and a refractive index detector was used. 0.05 g of sample was dissolved in 10 mL of THF and filtered through a microfilter to obtain 50 μL of the sample. Conversion was performed using a calibration curve derived from standard monodisperse polystyrenes (Tosoh Corporation: A-500, A-1000, A-2500, A-5000, F-1, F-2, F-4, F-10, F-20, F-40, F-80, F-128). Data processing was performed using a Tosoh Corporation GPC-8020 Model II version 6.00.

[0187] (5) Glass transition temperature (Tg): Measurements were performed in accordance with the IPC-TM-650 2.4.25.c standard. Specifically, the temperature was expressed as the extrapolated glass transition onset temperature (Tig) of the DSC chart obtained in the second cycle of differential scanning calorimetry. The differential scanning calorimetry instrument used was an EXSTAR6000 DSC6200 manufactured by SII NanoTechnology Inc. The measurement sample was prepared by punching a resin film, laminating it, and packing it in an aluminum capsule. Measurements were performed in two cycles, heating from room temperature to 280°C at a heating rate of 10°C / min.

[0188] (6) Thermal conductivity: Measurements were made using a NETZSCH LFA447 thermal conductivity meter by the transient hot wire method.

[0189] (7) Solvent solubility: The resin varnish was placed in a vacuum oven at 170°C and 0.2 kPa for 1 hour to remove the solvent, then mixed with methyl ethyl ketone (MEK) and heated to 60°C to completely dissolve, yielding an MEK solution with a non-volatile content of 30%. The solvent solubility was determined by the presence or absence of turbidity in the MEK solution upon cooling to room temperature. Transparent samples were rated as ○, and samples with even slight turbidity were rated ×.

[0190] (8)IR: A Fourier transform infrared spectrophotometer (Perkin Elmer Precisely, Spectrum One FT-IR Spectrometer 1760X) was used, with a wavenumber range of 600 to 4000 cm -1 The absorbance was measured.

[0191] (9) Copper foil peel strength: Measurements were made in accordance with the JIS C6481 standard.

[0192] (10) Moisture absorption rate: Measurements were performed using five 50mm x 50mm test pieces cut from laminates with etched copper foil. The test pieces were dried in a hot air circulating oven at 125°C in an air atmosphere for 24 hours, and then their mass was measured immediately. The test pieces were then stored in a treatment tank adjusted to a temperature of 85°C and a humidity of 85%RH, and the moisture absorption rate was calculated from the mass increase after 168 hours.

[0193] The abbreviations used in the examples and comparative examples are as follows:

[0194] [Epoxy resin] E1: 2,5-di-t-butylhydroquinone epoxy resin (Nippon Steel Chemical & Material Co., Ltd., YDC-1312, epoxy equivalent 176) E2: Hydroquinone epoxy resin (Nippon Steel Chemical & Material Co., Ltd., ZX-1027, epoxy equivalent 130) E3: 3,3',5,5'-tetramethyl-4,4'-biphenol epoxy resin (Mitsubishi Chemical Corporation, YX-4000H, epoxy equivalent 196) E4: Bisphenol A liquid epoxy resin (Nippon Steel Chemical & Material Co., Ltd., YD-128, epoxy equivalent 186) E5: Phenol novolac epoxy resin (Nippon Steel Chemical & Material Co., Ltd., YDPN-638, epoxy equivalent 177)

[0195] [Bifunctional phenolic compounds] P1: 2,5-di-t-butylhydroquinone (Tokyo Chemical Industry Co., Ltd., hydroxyl equivalent: 111) P2: 4,4'-biphenol (Honshu Chemical Industry Co., Ltd., biphenol, hydroxyl equivalent 93) P3: 3,3',5,5'-tetramethyl-4,4'-biphenol (Tokyo Chemical Industry Co., Ltd., hydroxyl equivalent: 121) P4: 3,3'-diphenyl-4,4'-biphenyldiol (manufactured by Sanko Co., Ltd., DOQ-O, hydroxyl equivalent: 169) P5: Bisphenol A (Nippon Steel Chemical & Material Co., Ltd., BPA, hydroxyl equivalent 114)

[0196] [catalyst] C1: Tris(2,6-dimethoxyphenyl)phosphine (Tokyo Chemical Industry Co., Ltd.) C2: 49% sodium hydroxide solution

[0197] [Hardening agent] D1: Dicyandiamide (manufactured by Nippon Carbide Industries Co., Ltd., dicyandiamide, active hydrogen equivalent 21)

[0198] [Curing accelerator] A1: 2-ethyl-4-methylimidazole (Curesol 2E4MZ, manufactured by Shikoku Chemicals Corporation)

[0199] Example 1 A glass reactor equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet was charged with 206 parts of E1, 194 parts of P4, and 44 parts of cyclohexanone at room temperature. The mixture was heated to 145°C while stirring under a nitrogen gas stream. 0.4 parts of C1 was added, and the reaction was continued for 10 hours while maintaining the reaction temperature at 160-170°C. Additional cyclohexanone was added as needed if the viscosity increased during the reaction. After the reaction was complete, the additional cyclohexanone was diluted with 156 parts of cyclohexanone and 400 parts of methyl ethyl ketone to obtain a phenoxy resin varnish (R1) with a nonvolatile content of 40% (solvent ratio: cyclohexanone / methyl ethyl ketone = 1 / 2). Figure 1 shows a GPC analysis of the resulting phenoxy resin varnish (R1).

[0200] The resulting phenoxy resin varnish was applied to a release film (made of polyimide film) using a roller coater to a thickness of 60 μm after solvent drying. After drying at 180°C for 20 minutes, the resulting dried film was peeled off from the release film. Two of these dried films were stacked and pressed in a vacuum press under conditions of 0.5 kPa vacuum, 200°C drying temperature, and 2 MPa pressure for 60 minutes to obtain a 100 μm-thick phenoxy resin film (F1). A 100 μm-thick spacer was used to adjust the thickness. The IR of the resulting phenoxy resin film (F1) is shown in Figure 2.

[0201] Example 2 A phenoxy resin varnish (R2) and a phenoxy resin film (F2) having a nonvolatile content of 40% were obtained in the same manner as in Example 1, except that 238 parts of E1 and 162 parts of P3 were used instead of 206 parts of E1 and 194 parts of P4.

[0202] Example 3 A phenoxy resin varnish (R3) and a phenoxy resin film (F3) having a nonvolatile content of 40% were obtained by the same procedure as in Example 1, except that 225 parts of E1, 65 parts of P1, and 110 parts of P4 were used instead of 206 parts of E1 and 194 parts of P4.

[0203] Example 4 A phenoxy resin varnish (R4) and a phenoxy resin film (F4) having a nonvolatile content of 40% were obtained in the same manner as in Example 1, except that 173 parts of E1, 44 parts of E2, 43 parts of P2, and 140 parts of P4 were used instead of 206 parts of E1 and 194 parts of P4.

[0204] Example 5 A phenoxy resin varnish (R5) and a phenoxy resin film (F5) having a nonvolatile content of 40% were obtained by the same procedure as in Example 1, except that 20 parts of E1, 199 parts of E3, and 181 parts of P4 were used instead of 206 parts of E1 and 194 parts of P4.

[0205] Example 6 A phenoxy resin varnish (R6) and a phenoxy resin film (F6) having a nonvolatile content of 40% were obtained by the same procedure as in Example 1, except that 249 parts of E1, 138 parts of P1, and 13 parts of P2 were used instead of 206 parts of E1 and 194 parts of P4.

[0206] Comparative Example 1 The same procedure as in Example 1 was carried out, except that 249 parts of E3 and 151 parts of P3 were used instead of 206 parts of E1 and 194 parts of P4. However, since the solubility in cyclohexanone after the reaction was poor, the additional mixture was diluted with 256 parts of cyclohexanone and 300 parts of methyl ethyl ketone to obtain a phenoxy resin varnish (RH1) (solvent ratio: cyclohexanone / methyl ethyl ketone = 1 / 1) with a nonvolatile content of 40% and a phenoxy resin film (FH1).

[0207] Comparative Example 2 A phenoxy resin varnish (RH2) and a phenoxy resin film (FH2) having a nonvolatile content of 40% were obtained in the same manner as in Example 1, except that 247 parts of E1 and 153 parts of P1 were used instead of 206 parts of E1 and 194 parts of P4.

[0208] Comparative Example 3 A phenoxy resin varnish (RH3) and a phenoxy resin film (FH3) having a nonvolatile content of 40% were obtained in the same manner as in Example 1, except that 250 parts of E4 and 150 parts of P5 were used instead of 206 parts of E1 and 194 parts of P4.

[0209] Example 7 A glass reactor equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet was charged with 50 parts of P1, 50 parts of P3, 80 parts of epichlorohydrin (ECH), 40 parts of toluene, 20 parts of n-butyl alcohol, and 2 parts of C2 at room temperature. The reaction was carried out for 10 hours while maintaining the reaction temperature at 60-70 °C. If the viscosity increased during the reaction, a mixed solvent (solvent ratio: toluene / n-butyl alcohol = 2 / 1) was added as needed. After the reaction was completed, the mixed solvent was diluted with the additional solvent to 264 parts, neutralized with 5.5 parts of oxalic acid and 24 parts of pure water, and then washed twice with 78 parts of pure water. The mixture was then refluxed and dehydrated to obtain a phenoxy resin varnish (R7) with a nonvolatile content of 30% (solvent ratio: toluene / n-butyl alcohol = 2 / 1). Using this phenoxy resin varnish (R7), the same procedure as in Example 1 was carried out to obtain a phenoxy resin film (F7).

[0210] The blending ratios (parts by weight) of Examples 1 to 7 and Comparative Examples 1 to 3 are all shown in Table 1. In the table, the item "Formula (2) ratio" indicates the mole percentage of phenylene groups represented by formula (2) in the total X of the phenoxy resin.

[0211] [Table 1]

[0212] The epoxy equivalent weight, Mw, and solvent solubility of the phenoxy resin varnish were measured, and the Tg and thermal conductivity of the phenoxy resin film were measured. The results are shown in Table 2.

[0213] [Table 2]

[0214] Example 8 250 parts (100 parts solids) of the phenoxy resin varnish (R1) obtained in Example 1, 50 parts of E5, 3.0 parts of D1, 0.2 parts of A1, 40 parts of propylene glycol monomethyl ether, and 40 parts of N,N-dimethylformamide were added and mixed uniformly with stirring to obtain a composition varnish.

[0215] Furthermore, the above composition varnish was impregnated into glass cloth (0.18 mm thick, manufactured by Nitto Boseki Co., Ltd., WEA 7628 XS13). The impregnated glass cloth was dried for 7 minutes in a hot air circulating oven at 150°C to obtain a prepreg. Eight sheets of the obtained prepreg were stacked on top and bottom with copper foil (3EC-III, manufactured by Mitsui Mining & Smelting Co., Ltd., 35 μm thick), and vacuum pressed at 2 MPa under temperature conditions of 130°C x 15 minutes + 190°C x 80 minutes to obtain a 1.6 mm thick laminate (B1).

[0216] Example 9 A laminate (B2) was obtained in the same manner as in Example 8, except that the phenoxy resin varnish (R5) was used instead of the phenoxy resin varnish (R1).

[0217] Comparative Example 4 A laminate (BH1) was obtained in the same manner as in Example 8, except that the phenoxy resin varnish (RH1) was used instead of the phenoxy resin varnish (R1).

[0218] Comparative Example 5 A laminate (BH2) was obtained in the same manner as in Example 8, except that the phenoxy resin varnish (RH3) was used instead of the phenoxy resin varnish (R1).

[0219] The laminate was used to measure Tg, thermal conductivity, copper foil peel strength, and moisture absorption rate (water resistance). The results are shown in Table 3.

[0220] [Table 3]

[0221] The results in Tables 2 and 3 show that the examples using phenoxy resins incorporating phenylene and biphenylene groups have higher thermal conductivity and heat resistance than phenoxy resins containing only biphenylene or bisphenol groups, and their good solvent solubility allows for a reduction in the amount of highly soluble, high-boiling-point solvents used. This improves prepreg drying during the laminate manufacturing process and minimizes the impact of residual solvents, resulting in excellent heat resistance and low water absorption.

Claims

1. A resin composition characterized by containing 0.1 to 100 parts by mass of a curing agent as a solid content per 100 parts by mass of a phenoxy resin solid content represented by the following formula (1) and having a weight average molecular weight of 10,000 to 200,000: 【Chemical 1】 (wherein X is selected from a phenylene group represented by the following formula (4) and a biphenylene group represented by the following formula (5), 5 to 95 mol % of X are phenylene groups represented by the following formula (4), Z is independently a hydrogen atom or a glycidyl group, and n is the average number of repetitions and is 10 to 500.) 【Chemistry 2】 (wherein R 6 and R 7 are each independently a hydrogen atom, a t-butyl group, or a t-octyl group.) 【Chemistry 3】 (wherein R 8 to R 15 are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a phenyl group.)

2. 2. The resin composition according to claim 1, wherein, in the phenoxy resin represented by formula (1), X has both a phenylene group represented by the following formula (6) and / or formula (7) and a biphenylene group represented by the following formula (8) and / or formula (9): 【Chemistry 4】 (In formula (6), t-Bu is a t-butyl group.)

3. 2. The resin composition according to claim 1, comprising a phenoxy resin, an epoxy resin, and a curing agent, wherein the mass ratio of the solid content of the phenoxy resin to the solid content of the epoxy resin is 99 / 1 to 1 / 99.

4. 2. The resin composition according to claim 1, wherein the curing agent is at least one selected from the group consisting of acrylic ester resins, melamine resins, urea resins, phenolic resins, acid anhydride compounds, amine compounds, imidazole compounds, amide compounds, cationic polymerization initiators, organic phosphines, polyisocyanate compounds, blocked isocyanate compounds, and active ester curing agents.

5. 2. The resin composition according to claim 1, further comprising an inorganic filler.

6. A circuit board material obtained from the resin composition according to claim 1.

7. 2. The method for producing a resin composition according to claim 1, wherein a bifunctional epoxy resin containing a bifunctional epoxy resin represented by the following formula (10) is reacted with a bifunctional phenol compound containing a bifunctional phenol compound represented by the following formula (11) in the presence of a catalyst to obtain a phenoxy resin: 【Chemistry 5】 (Here, A and B are both selected from the phenylene group represented by the above formula (4) and the biphenylene group represented by the above formula (5), and 5 to 95 mol % of A and B combined are phenylene groups represented by the above formula (4). G is a glycidyl group, and m is the average value of the number of repetitions and is 0 to 6.)

8. The method for producing a resin composition according to claim 1, wherein bifunctional phenol compounds represented by the following formulas (14) and (15) are used as raw materials, the ratio of the bifunctional phenol compound having a phenylene group represented by formula (14) being 5 to 95 mol % in the raw material bifunctional phenol compounds, and the raw material bifunctional phenol compounds are reacted with epihalohydrin in the presence of an alkali to obtain a phenoxy resin having a weight average molecular weight of 10,000 to 200,000. 【Chemistry 6】 (Here, R 6 and R 7 in formula (14) have the same meanings as in formula (4) above, and R 8 to R 15 in formula (15) have the same meanings as in formula (5) above.)

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