Benzoxazine resin composition

Abstract

The present invention addresses the problem of providing a resin material having excellent heat resistance and dielectric characteristics using a benzoxazine compound. The present invention provides, as a solution, a benzoxazine resin composition comprising a resin component (A) and a resin component (B). The resin component (A) is a benzoxazine compound represented by general formula (1). The resin component (B) is an epoxy resin having an alicyclic structure. (In the formula, each R1 independently represents an alkylene group having 1-4 carbon atoms, and X represents a cycloalkylidene group having 5-20 carbon atoms.)

Description

Benzoxazine resin composition

[0001] The present invention relates to a benzoxazine resin composition, specifically to a curable benzoxazine resin composition containing a benzoxazine compound having benzoxazine rings at both ends of a cycloalkylidene group and further having an allyl group, and an epoxy resin.

[0002] Benzoxazine compounds are compounds synthesized by reacting phenols, amines, and formaldehyde. They are known as thermosetting resin raw materials that cure by ring-opening polymerization of the benzoxazine ring without producing volatile by-products upon heating. They are used as raw materials for applications such as molded articles usable as insulating substrate materials, liquid crystal alignment agents, semiconductor encapsulation resin compositions, adhesives, potting materials, laminating materials, coating materials, and paints. These applications require excellent heat resistance, ensuring stability and reliability at high temperatures. However, issues remain regarding heat resistance, such as a lack of heat resistance above 200°C. To address these issues, benzoxazine compositions incorporating allyl groups have been reported (Patent Document 1). While Patent Document 1 describes that allyl-group-containing benzoxazine resins and allyl-group-containing naphthoxazine resins can be used to form resin compositions using components such as epoxy resins, phenolic resins, and melamine resins, the specific physical properties of the resulting cured products are not disclosed.

[0003] Japanese Patent Application Laid-Open No. 2003-286320

[0004] Among the uses of benzoxazine compounds, materials having excellent heat resistance and excellent dielectric properties are required for use as components for electric and electronic devices, such as printed circuit boards and sealants for semiconductors and electronic components. An object of the present invention is to provide a resin material using a benzoxazine compound, which has excellent heat resistance and dielectric properties.

[0005] As a result of intensive research to solve the above-mentioned problems, the present inventors have found that a cured product obtained using a resin composition containing a benzoxazine compound which uses a cycloalkylidene bisphenol as a raw material, has benzoxazine rings at both ends of the cycloalkylidene group, and further has allyl groups, and an epoxy resin having a cyclic aliphatic structure, is a resin material having excellent heat resistance and dielectric properties, and have completed the present invention.

[0006] The present invention is as follows: 1. A benzoxazine resin composition containing resin component (A) and resin component (B), wherein resin component (A): a benzoxazine compound represented by general formula (1), and resin component (B): an epoxy resin having a cycloaliphatic structure. (In the formula, R １ each independently represent an alkylene group having 1 to 4 carbon atoms, and X represents a cycloalkylidene group having 5 to 20 carbon atoms. 2. The benzoxazine resin composition according to 1., wherein X in general formula (1) is at least one selected from a cyclohexylidene group, a 3-methylcyclohexylidene group, a 4-methylcyclohexylidene group, a 3,3,5-trimethylcyclohexylidene group, and a cyclododecanylidene group. 3. The benzoxazine resin composition according to 1., wherein the content of resin component (A) is in the range of 1% by weight to 99% by weight, based on the total amount of resin components. 4. The benzoxazine resin composition according to 1., wherein resin component (B) is at least one selected from a cycloalkylidene bisphenol-type epoxy resin, a dicyclopentadiene-type epoxy resin, and an alicyclic epoxy resin. 5. The benzoxazine resin composition according to 1., further comprising component (D). Component (D): Curing accelerator 6. A cured product of the benzoxazine resin composition described in 1.

[0007] The benzoxazine resin composition of the present invention can give a cured product having excellent heat resistance and dielectric properties, and is therefore particularly useful as a resin material for electrical and electronic devices, such as printed circuit boards and sealants for semiconductors and electronic components.

[0008] The benzoxazine compound represented by formula (1-4) obtained in Synthesis Example 1 １1 is a diagram showing a spectrum obtained by H-NMR analysis of the benzoxazine compound represented by formula (1-5) obtained in Synthesis Example 2. １ FIG. 1 is a diagram showing a spectrum obtained by H-NMR analysis.

[0009] <Benzoxazine Resin Composition> The benzoxazine resin composition of the present invention contains a benzoxazine compound represented by general formula (1) as resin component (A) and an epoxy resin as resin component (B).

[0010] <Resin Component (A): Benzoxazine Compound Represented by General Formula (1)> Resin component (A) in the benzoxazine resin composition of the present invention is a benzoxazine compound represented by general formula (1). (In the formula, R １ each independently represents an alkylene group having 1 to 4 carbon atoms, and X represents a cycloalkylidene group having 5 to 20 carbon atoms. １are each independently an alkylene group having 1 to 4 carbon atoms, preferably an alkylene group having 1 or 2 carbon atoms, more preferably a methylene group or a 1,2-ethylene group, and particularly preferably a methylene group. X in general formula (1) represents a cycloalkylidene group having 5 to 20 carbon atoms, which may contain an alkyl group as a branched chain, and in this case, the number of carbon atoms of the alkyl group as a branched chain is also included in the number of carbon atoms of 5 to 20. The cycloalkylidene group preferably has 5 to 15 carbon atoms, more preferably 6 to 12 carbon atoms, even more preferably 6 to 10 carbon atoms, and particularly preferably 6 to 9 carbon atoms. Specific examples of the cycloalkylidene group include a cyclopentylidene group (5 carbon atoms), a cyclohexylidene group (6 carbon atoms), a 3-methylcyclohexylidene group (7 carbon atoms), a 4-methylcyclohexylidene group (7 carbon atoms), a 3,3,5-trimethylcyclohexylidene group (9 carbon atoms), a cycloheptylidene group (7 carbon atoms), a bicyclo[2.2.1]heptane-2,2-diyl group (7 carbon atoms), a 1,7,7-trimethylbicyclo[2.2.1]heptane-2,2-diyl group (10 carbon atoms), a 4,7,7-trimethylbicyclo[2.2.1]heptane-2,2-diyl group (10 carbon atoms), a tricyclo[5.2.1.0 ２，６ ]decane-8,8-diyl group (10 carbon atoms), 2,2-adamantylidene group (10 carbon atoms), cyclododecanylidene group (12 carbon atoms), etc. Preferred are cyclohexylidene group (6 carbon atoms), 3-methylcyclohexylidene group (7 carbon atoms), 4-methylcyclohexylidene group (7 carbon atoms), 3,3,5-trimethylcyclohexylidene group (9 carbon atoms), and cyclododecanylidene group (12 carbon atoms), more preferred are 3-methylcyclohexylidene group (7 carbon atoms), 4-methylcyclohexylidene group (7 carbon atoms), 3,3,5-trimethylcyclohexylidene group (9 carbon atoms), and cyclododecanylidene group (12 carbon atoms), and particularly preferred is 3,3,5-trimethylcyclohexylidene group (9 carbon atoms).

[0011] Specific examples of the benzoxazine compound represented by general formula (1) include compounds represented by chemical formulas (1-1) to (1-20). Among these, at least one selected from compounds (1-1) to (1-5) and compounds (1-11) to (1-15) is preferred, at least one selected from compounds (1-1), (1-4), (1-5), (1-11), (1-14) and (1-15) is more preferred, at least one selected from compounds (1-4), (1-5), (1-14) and (1-15) is even more preferred, and at least one selected from compounds (1-4) and (1-14) is particularly preferred. The benzoxazine compound represented by general formula (1) can be stored for a long period of time even under room temperature conditions and has good storage stability compared to the conventionally known benzoxazine compound represented by formula (i). Therefore, as a raw material for producing the benzoxazine resin composition of the present invention, it is easy to store and handle in industrial production.

[0012] <Method for producing benzoxazine compound represented by general formula (1)> There are no particular limitations on the starting materials and production method for the benzoxazine compound represented by general formula (1). For example, as exemplified by the following reaction formula, a production method can be mentioned in which a bisphenol compound represented by general formula (2), an amine compound represented by general formula (3), and formaldehyde are subjected to a dehydration condensation reaction to cyclize, thereby obtaining the target benzoxazine compound represented by general formula (1). (In the formula, R １ , X is the same as defined in general formula (1).

[0013] In the above production method, a bisphenol compound represented by the general formula (2), an amine compound represented by the general formula (3), and formaldehydes are used as starting materials. Specific examples of the bisphenol compound represented by the general formula (2) include bisphenol Z (1,1-bis(4-hydroxyphenyl)cyclohexane), 1,1-bis(4-hydroxyphenyl)-3-methylcyclohexane, 1,1-bis(4-hydroxyphenyl)-4-methylcyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 1,1-bis(4-hydroxyphenyl)cyclododecane, 2,2-bis(4-hydroxyphenyl)bicyclo[2.2.1]heptane, 2,2-bis(4-hydroxyphenyl)-1,7,7-trimethylbicyclo[2.2.1]heptane, 2,2-bis(4-hydroxyphenyl)-4,7,7-trimethylbicyclo[2.2.1]heptane, 4,4'-(tricyclo[5.2.1.0]heptane), ２，６]decane-8,8-diyl)bisphenol, 2,2-bis(4-hydroxyphenyl)adamantane, etc. Among these, bisphenol Z (1,1-bis(4-hydroxyphenyl)cyclohexane), 1,1-bis(4-hydroxyphenyl)-3-methylcyclohexane, 1,1-bis(4-hydroxyphenyl)-4-methylcyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, or 1,1-bis(4-hydroxyphenyl)cyclododecane is preferred, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane or 1,1-bis(4-hydroxyphenyl)cyclododecane is more preferred, and 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane is particularly preferred. Specific examples of the amine compound represented by general formula (3) include allylamine, 3-butene-1-amine, and 4-pentene-1-amine. Among these, allylamine is preferred. The amine compound represented by general formula (3) can also be used as a salt with an inorganic acid such as hydrochloric acid or sulfuric acid. In such cases, the reaction is carried out in the presence of an alkaline aqueous solution prepared by dissolving sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, or the like in water. Specific examples of formaldehydes include aqueous formaldehyde solutions, 1,3,5-trioxane, and paraformaldehyde. In the above production method, the amount of formaldehyde used, calculated as the amount involved in the synthesis reaction of benzoxazine compound (A) as formaldehyde, is preferably in the range of 4.0 to 20.0 mol, more preferably in the range of 4.0 to 16.0 mol, and even more preferably in the range of 4.0 to 12.0 mol, per mol of the bisphenol compound represented by general formula (2). In the above production method, the amount of the amine compound represented by general formula (3) used is preferably in the range of 2.0 to 10.0 mol, more preferably in the range of 2.0 to 8.0 mol, and even more preferably in the range of 2.0 to 6.0 mol, per 1 mol of the bisphenol compound represented by general formula (2).For example, one mole of trioxane participates in the reaction as three moles of formaldehyde.

[0014] A catalyst for promoting the reaction is not particularly required, but an acid catalyst or a base catalyst can be used as necessary. In this case, examples of acid catalysts that can be used include concentrated hydrochloric acid, hydrochloric acid gas, trifluoroacetic acid, methanesulfonic acid, p-toluenesulfonic acid, benzoic acid, and mixtures thereof. Examples of base catalysts that can be used include, but are not limited to, sodium hydroxide, sodium carbonate, triethylamine, triethanolamine, and mixtures thereof. Among these, p-toluenesulfonic acid and sodium hydroxide are preferred, and sodium hydroxide is more preferred.

[0015] The reaction is typically carried out in the presence of a solvent. The solvent is not particularly limited as long as it does not inhibit the reaction. Preferred examples of the solvent include aromatic hydrocarbons having 6 to 9 carbon atoms, such as toluene and xylene; aliphatic alkyls having 5 to 8 carbon atoms, such as hexane, heptane, and cyclohexane; aliphatic esters having 3 to 6 carbon atoms, such as methyl acetate, ethyl acetate, methyl propionate, and butyl acetate; and water. Among these, aromatic hydrocarbons having 6 to 9 carbon atoms and aliphatic esters having 3 to 6 carbon atoms are more preferred, with aliphatic esters having 3 to 6 carbon atoms being even more preferred. These solvents can be used alone or in combination. The amount of solvent used is not particularly limited as long as it does not interfere with the reaction. However, a range of 200 to 400 parts by weight, and more preferably 250 to 300 parts by weight, per 100 parts by weight of the bisphenol compound represented by general formula (2) is typically preferred.

[0016] The reaction temperature is usually preferably in the range of 30 to 100°C, more preferably in the range of 30 to 80°C, and particularly preferably in the range of 40 to 70°C. The reaction pressure may be normal pressure, or may be increased or reduced pressure. There is no limitation on the method for mixing the raw materials, the bisphenol compound represented by general formula (2), formaldehydes, and the amine compound represented by general formula (3). Examples include (a) a method in which an amine compound represented by general formula (3) is mixed with a mixture containing a bisphenol compound represented by general formula (2) and formaldehydes to carry out the reaction, and (b) a method in which a bisphenol compound represented by general formula (2) is mixed with a mixture containing formaldehydes and an amine compound represented by general formula (3). These mixtures may contain the above-mentioned solvents and catalysts, and there are no limitations on the method for mixing the catalyst, but it is preferable to mix the catalyst before mixing the amine compound represented by general formula (3). In the production method of the present invention, there is no limitation on the method for mixing the remaining raw materials with the raw material mixture. However, from the viewpoint of reaction selectivity and suppressing the production of high molecular weight components as by-products, it is preferable to mix the raw materials continuously or intermittently, for example, over a period of 10 minutes to 2 hours, rather than mixing them all at once.

[0017] In another embodiment, the method may include a step of removing water derived from the raw materials or water generated during the reaction from the reaction system. The step of removing the generated water from the reaction solution is not particularly limited, and the generated water can be removed by azeotropically distilling the generated water with the solvent system in the reaction solution. The generated water can be removed from the reaction system using, for example, a pressure-equalizing dropping funnel equipped with a stopcock, a Dimroth condenser, a Dean-Stark apparatus, or the like.

[0018] After the reaction is completed, the resulting reaction mixture can be used to obtain the benzoxazine compound represented by general formula (1) by a known method. For example, after the reaction, the reaction mixture may be subjected to a treatment such as deactivating the catalyst used or washing with water, and the target product can be obtained as a residual liquid by distilling off the remaining raw materials and solvent from the reaction mixture. Alternatively, the target product can be obtained by precipitating the residual liquid by adding a poor solvent, or by adding a solvent to the reaction mixture to cause crystallization and filtering the crystals to obtain a powder or granular target product. The benzoxazine compound isolated by the above method can be purified to a high purity by conventional purification means, such as washing with a solvent or water or recrystallization.

[0019] The benzoxazine compound represented by general formula (1) may contain a by-product compound produced in the reaction for producing the compound. Examples of such by-products include compounds with a higher molecular weight than the benzoxazine compound represented by general formula (1). The purity of the benzoxazine compound represented by general formula (1) is not particularly limited, but can be analyzed by gel permeation chromatography using a differential refractometer as a detector. The purity is typically in the range of 10 to 100 area%, preferably 20 to 100 area%, more preferably 40 to 100 area%, and particularly preferably 60 to 100 area%, based on the area of ​​all peaks detected by such analysis.

[0020] <Resin Component B: Epoxy Resin Having a Cycloaliphatic Structure> Resin component (B) in the benzoxazine resin composition of the present invention is an epoxy resin having a cycloaliphatic structure. Examples of the epoxy resin having a cycloaliphatic structure include cycloalkylidene bisphenol-type epoxy resins, dicyclopentadiene-type epoxy resins, and alicyclic epoxy resins, and it is preferable to use at least one selected from these. Among these, it is more preferable to use at least one selected from cycloalkylidene bisphenol-type epoxy resins and dicyclopentadiene-type epoxy resins, and it is particularly preferable to use a dicyclopentadiene-type epoxy resin.

[0021] (Cycloalkylidene bisphenol-type epoxy resin) Specific examples of cycloalkylidene bisphenol-type epoxy resins include compounds represented by the following formula:

[0022] (Dicyclopentadiene-Type Epoxy Resin) Examples of dicyclopentadiene-type epoxy resins include compounds represented by the following formula: Commercially available dicyclopentadiene epoxy resins include, for example, "Epiclon" HP7200, "Epiclon" HP7200L, and "Epiclon" HP7200H (manufactured by DIC Corporation), "Tactix" (registered trademark) 558 (manufactured by Huntsman Advanced Materials), and XD-1000 (manufactured by Nippon Kayaku Co., Ltd.).

[0023] (Alicyclic Epoxy Resin) Examples of alicyclic epoxy resins include (3',4'-epoxycyclohexane)methyl-3,4-epoxycyclohexanecarboxylate, (3',4'-epoxycyclohexane)octyl-3,4-epoxycyclohexanecarboxylate, 1-methyl-4-(2-methyloxiranyl)-7-oxabicyclo[4.1.0]heptane, limonene dioxide, 1,2-epoxy-4-vinylcyclohexane, and compounds represented by the following formula: Commercially available products of (3',4'-epoxycyclohexane)methyl-3,4-epoxycyclohexanecarboxylate include, for example, "Celloxide" (registered trademark, the same applies hereinafter) 2021P (manufactured by Daicel Corporation) and CY179 (manufactured by Huntsman Advanced Materials).

[0024] <Resin Component C: Other Benzoxazine Compound Components> The benzoxazine resin composition of the present invention can contain, as resin component (C), benzoxazine compounds other than the benzoxazine compound represented by general formula (1) (hereinafter, may be referred to as "other benzoxazine compounds"), as long as the effects of the present invention are not significantly impaired. Examples of other benzoxazine compounds include benzoxazine compounds having structures represented by general formulas (A) to (C), excluding the benzoxazine compound represented by general formula (1). (In the formula, Ra represents a divalent group having 1 to 30 carbon atoms, each Rb represents a monovalent group having 1 to 10 carbon atoms which may have a substituent, and each n represents independently 0 or 1.) (In the formula, Rc represents a divalent group having 1 to 30 carbon atoms, a direct bond, an oxygen atom, a sulfur atom, a carbonyl group, or a sulfonyl group, and each Rd independently represents a monovalent group having 1 to 10 carbon atoms.) (In the formula, each Re independently represents a monovalent group having 1 to 10 carbon atoms, and m represents 0 or 1.)

[0025] In the benzoxazine compound having a structure represented by general formula (A), Ra represents a divalent group having 1 to 30 carbon atoms. Specific examples thereof include alkylene groups such as 1,2-ethylene, 1,4-butylene, and 1,6-hexylene; alkylene groups containing a cyclic structure such as 1,4-cyclohexylene, dicyclopentadienylene, and adamantylene; and arylene groups such as 1,4-phenylene, 4,4'-biphenylene, diphenylether-4,4'-diyl, diphenylether-3,4'-diyl, diphenylketone-4,4'-diyl, and diphenylsulfone-4,4'-diyl. In the benzoxazine compound having a structure represented by general formula (A), each Rb independently represents a monovalent group having 1 to 10 carbon atoms. Specific examples thereof include alkyl groups such as methyl, ethyl, propyl, and butyl, alkenyl groups such as vinyl and allyl, alkynyl groups such as ethynyl and propargyl, and aryl groups such as phenyl and naphthyl, and these groups may further have a substituent such as an alkoxy group having 1 to 4 carbon atoms, an acyl group having 1 to 4 carbon atoms, a halogen atom, a carboxyl group, a sulfo group, an allyloxy group, a hydroxy group, or a thiol group. Examples of benzoxazine compounds having a structure represented by general formula (A) include P-d-type benzoxazine manufactured by Shikoku Chemicals Corporation, and JBZ-OP100N and JBZ-BP100N manufactured by JFE Chemical Corporation.

[0026] In the benzoxazine compound having a structure represented by general formula (B), Rc represents a divalent group having 1 to 30 carbon atoms, a direct bond, an oxygen atom, a sulfur atom, a carbonyl group, or a sulfonyl group. Examples of the divalent group having 1 to 30 carbon atoms include alkylene groups such as methylene, 1,2-ethylene, 1,4-butylene, and 1,6-hexylene; alkylene groups containing a cyclic structure such as 1,4-cyclohexylene, dicyclopentadienylene, and adamantylene; and alkylidene groups such as ethylidene, propylidene, isopropylidene, butylidene, phenylethylidene, cyclopentylidene, cyclohexylidene, cycloheptylidene, cyclododecylidene, 3,3,5-trimethylcyclohexylidene, and fluorenylidene. In the benzoxazine compound having a structure represented by general formula (B), each Rd independently represents a monovalent group having 1 to 10 carbon atoms. Specific examples thereof include alkyl groups such as methyl, ethyl, propyl, and butyl, alkenyl groups such as vinyl and allyl, alkynyl groups such as ethynyl and propargyl, and aryl groups such as phenyl and naphthyl, and these groups may further have a substituent such as an alkoxy group having 1 to 4 carbon atoms, an acyl group having 1 to 4 carbon atoms, a halogen atom, a carboxyl group, a sulfo group, an allyloxy group, a hydroxy group, and a thiol group. Examples of benzoxazine compounds having a structure represented by general formula (B) include Fa-type benzoxazine manufactured by Shikoku Chemical Industry Co., Ltd. and BS-BXZ manufactured by Konishi Chemical Industry Co., Ltd.

[0027] In the benzoxazine compound having a structure represented by general formula (C), each Re independently represents a monovalent group having 1 to 10 carbon atoms. Specific examples thereof include alkyl groups such as a methyl group, an ethyl group, a propyl group, and a butyl group; alkenyl groups such as a vinyl group and an allyl group; alkynyl groups such as an ethynyl group and a propargyl group; and aryl groups such as a phenyl group and a naphthyl group. These groups may further have a substituent such as an alkoxy group having 1 to 4 carbon atoms, an acyl group having 1 to 4 carbon atoms, a halogen atom, a carboxyl group, a sulfo group, an allyloxy group, a hydroxy group, or a thiol group.

[0028] (Amount of Resin Components Used) In the benzoxazine resin composition of the present invention, resin component (A), resin component (B), and resin component (C) may be collectively referred to as resin components. In the benzoxazine resin composition of the present invention, the content of resin component (A) is preferably in the range of 1% by weight to 99% by weight, more preferably in the range of 5% by weight to 95% by weight, even more preferably in the range of 10% by weight to 90% by weight, and particularly preferably in the range of 20% by weight to 70% by weight, relative to the total amount of the resin components (resin component (A) and resin component (B) or resin component (A), resin component (B), and resin component (C)).

[0029] (Component (D)) The benzoxazine resin composition of the present invention can be cured by heat alone, but can and preferably does further contain a curing accelerator as component (D). Usable curing accelerators are not particularly limited, and examples include tertiary amines such as 1,8-diaza-bicyclo[5.4.0]undecene-7, triethylenediamine, and tris(2,4,6-dimethylaminomethyl)phenol; imidazoles such as 2-ethyl-4-methylimidazole and 2-methylimidazole; phosphorus compounds such as triphenylphosphine, tris(p-tolyl)phosphine, tetraphenylphosphonium bromide, tetraphenylphosphonium tetraphenylborate, and tetra-n-butylphosphonium-O,O-diethylphosphorodithioate; quaternary ammonium salts; organometallic salts; and derivatives thereof. These may be used alone or in combination. Of these curing accelerators, tertiary amines, imidazoles, and phosphorus compounds are preferably used.

[0030] In the benzoxazine resin composition of the present invention, the content of component (D) is preferably in the range of 0.01 to 10 parts by weight, more preferably in the range of 0.05 to 5 parts by weight, and even more preferably in the range of 0.1 to 5 parts by weight, per 100 parts by weight of the total amount of the resin components.

[0031] <Component E: Filler> The benzoxazine resin composition of the present invention can further contain component (E) filler. Examples of the filler that can be used as component (E) include inorganic fillers such as silicon oxide, silica, aluminum oxide, magnesium oxide, boron nitride, aluminum nitride, silicon nitride, and silicon carbide, and reinforcing fibers such as carbon fiber, glass fiber, aramid fiber, nylon fiber, high-strength polyester fiber, boron fiber, and steel fiber.

[0032] In the benzoxazine resin composition of the present invention, the content of component (E) is preferably in the range of 100 parts by weight or more and 1,000 parts by weight or less, and more preferably in the range of 300 parts by weight or more and 1,000 parts by weight or less, per 100 parts by weight of the total amount of the resin components.

[0033] The method for adding each component used in the benzoxazine resin composition of the present invention is not particularly limited, and conventionally known methods can be employed. Examples include adding the components during the synthesis or polymerization of a polymeric material, adding a polymeric resin to a molten resin, for example, during a melt extrusion process, impregnating a polymeric resin product, or the like, and uniformly dissolving and dispersing the components in a solvent and then volatilizing the solvent. The benzoxazine resin composition of the present invention may contain water or residual solvent, which can lead to the generation of bubbles during curing. To prevent this, a vacuum degassing treatment is preferably performed as a pretreatment. The temperature of this vacuum degassing treatment is not particularly limited as long as it is a temperature at which the benzoxazine resin composition of the present invention is in a molten state. However, it is preferable to perform the treatment at an upper limit of 150°C because this prevents curing and facilitates degassing. The pressure of the vacuum degassing treatment is not particularly limited, but a lower pressure (higher degree of vacuum) is preferable. The treatment may be performed either in air or in a nitrogen-substituted atmosphere. This vacuum degassing treatment is continued until bubbles are no longer visible.

[0034] <Cured Product of Benzoxazine Resin Composition> Examples of methods for producing the cured product of the present invention include a method in which the benzoxazine resin composition is heated to a predetermined temperature to cure, a method in which the benzoxazine resin composition is heated and melted and poured into a mold or the like, and the mold is further heated to cure and mold, and a method in which the molten material is poured into a preheated mold and cured. The cured product of the present invention can be cured by ring-opening polymerization under the same curing conditions as for ordinary benzoxazine. The curing temperature is usually in the range of 70 to 300°C, preferably 100 to 280°C, and more preferably 100 to 260°C. However, to improve the mechanical properties of the resulting cured product, a temperature in the range of 100 to 240°C is particularly preferred. When curing is performed within this temperature range, the reaction time may be approximately 1 to 10 hours.

[0035] The benzoxazine resin composition of the present invention can be suitably used as a resin raw material for varnishes that can be applied to various substrates, prepregs impregnated with the varnish, copper-clad laminates, printed circuit boards, sealants for semiconductors and electronic components, molded electrical and electronic components, automobile parts, laminates, paints, resist inks, etc., and the cured product can be suitably used as a material resin for these products. Among these, the cured product of the benzoxazine resin composition of the present invention has excellent heat resistance and dielectric properties, and is therefore useful as a resin material for prepregs, copper-clad laminates, printed circuit boards, sealants for semiconductors and electronic components, and molded electrical and electronic components.

[0036] The present invention will be described in more detail below with reference to the following examples. <Analytical Method> 1. Liquid Chromatography: LC Measurement Apparatus: High-Performance Liquid Chromatography Analyzer: Prominence UFLC (Shimadzu Corporation) Pump: LC-20AD Column Oven: CTO-20A Detector: SPD-20A Column: HALO-C18 (inner diameter 3 mm, length 75 mm) Oven Temperature: 50°C Flow Rate: 0.7 mL / min Detection Wavelength: 280 nm Mobile Phase: (A) 0.2% by volume aqueous acetic acid solution, (B) tetrahydrofuran Gradient Conditions: (B) vol% 0-5 min, 10→20%, 5-10 min, 20%, 10-18 min, 20→100%, 18-22 min, 100% 2. Gel permeation chromatography: GPC Apparatus: HLC-8320 / manufactured by Tosoh Corporation Detector: differential refractometer (RI) [Measurement conditions] Flow rate: 1 mL / min. Eluent: tetrahydrofuran Temperature: 40°C Wavelength: 254 nm Sampling interval: 100 sec. Measurement sample: solution obtained by diluting 10 mg of benzoxazine compound 50 times with tetrahydrofuran Injection amount: 10 μL [Column] (from upstream) Guard Column HXL-L + G4000HXL + G3000HXL + G2000HXL x 2 (7.8 mm ID x 30 cm, manufactured by Tosoh Corporation) 3. NMR analysis Measurement apparatus: Fourier transform nuclear magnetic resonance AVANCE III HD 400 (manufactured by BRUKER) A measurement sample was dissolved in deuterated chloroform, and １H-NMR spectrum was measured. 4. Measurement of glass transition temperature (Tg) (dynamic mechanical analysis (DMA)) Apparatus: DMA850 / manufactured by TA Instruments Japan, Inc. Measurement conditions: three-point bending Measurement temperature: 30 to 310°C Measurement frequency: 1.0 (Hz) Sample dimensions: (60 mm x 15 mm x 2 mm) Heating rate: 1.0°C / min. 5. Evaluation of dielectric properties The films (sample size: width 1.5 mm, length 8.0 mm) prepared in the examples and comparative examples were measured for relative permittivity and dielectric loss tangent using the following apparatus (sample size: width 1.5 mm, length 8.0 mm). Measurement equipment: PNA network analyzer N522B (manufactured by Keysight Technologies, Inc.) Cavity resonator: CP531 for 10 GHz (manufactured by Kanto Electronics Application Development Co., Ltd.) [Measurement conditions] Test method: Compliant with IEC 62180 (cavity resonator perturbation method) Test conditions: Frequency: 10 GHz Number of measurements: n = 2

[0037] Synthesis Example 1 (Synthesis of benzoxazine compound represented by formula (1-4)) A 2-L four-neck flask equipped with a thermometer, stirrer, condenser, and dropping funnel was charged with 130 g (1.3 mol) of allylamine hydrochloride. Then, with stirring, 110 g (1.3 mol) of 48% aqueous NaOH solution was slowly added over 5 minutes while checking the temperature rise. After confirming that the pH of the aqueous layer was approximately 9-10, 107 g (3.3 mol) of paraformaldehyde (purity: 92%) was added in small portions over 30 minutes. During this time, the temperature of the reaction system was confirmed to rise from 30°C to 55°C. The mixture was then air-cooled with stirring, and after confirming that the temperature had dropped to 30°C, stirring was continued for 1 hour at 30°C. After stirring was completed, 586 g of ethyl acetate and 210 g of 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane were added to the flask. The temperature of the liquid in the flask was then raised to 55°C, and the reaction was carried out for 24 hours, 3 hours at 60°C, 5 hours at 65°C, and 1 hour at 70°C, confirming the disappearance of 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane. The temperature of the liquid in the flask was cooled to 40°C. Analysis of the reaction solution by GPC revealed that the proportion of benzoxazine compounds present in the reaction solution was 75 area%, with the remaining 25 area% being compounds with a higher molecular weight than the benzoxazine compounds (high molecular weight components). The reaction-terminated liquid was mixed with 400 g of pure water, stirred for 30 minutes, allowed to stand, and after confirming separation from the organic layer, the aqueous layer was removed. This water washing procedure was repeated six times, and the pH of the aqueous layer was confirmed to be 7-8. The solvent was then removed by distillation under reduced pressure at 40°C. After the solvent was distilled off, the mixture was cooled to obtain a non-flowable solid benzoxazine compound. The obtained benzoxazine compound was analyzed by GPC under the above analytical conditions, and the purity was 70 area % and the content of high molecular weight components was 30 area %. The obtained distillation residue was heated to 90°C, poured into a metal tray, cooled to room temperature, and crushed to obtain 250 g of a yellow solid benzoxazine compound. The amount of solvent contained in the solid was 1.0 wt %. The yield was 78 mol % based on the 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane used. The obtained solid was １As a result of H-NMR analysis, peaks derived from the 3,3,5-trimethylcyclohexylidene group were observed around 0.4 and 0.8 to 1.0 ppm, a peak derived from the benzoxazine moiety was observed around 3.3 to 4.0 ppm, a peak derived from allylamine was observed around 4.8 to 5.2 ppm, and a peak derived from aromatics was observed around 6.6 to 7.3 ppm. １ The H-NMR spectrum is shown in Figure 1. From the analysis results, it was revealed that the compound was the target benzoxazine compound represented by formula (1-4).

[0038] Synthesis Example 2 (Synthesis of benzoxazine compound represented by formula (1-5)) A 2-L four-neck flask equipped with a thermometer, stirrer, condenser, and dropping funnel was charged with 120 g (1.2 mol) of allylamine hydrochloride. Then, while stirring, 101 g (1.2 mol) of 48% aqueous NaOH solution was slowly added over 5 minutes while checking the temperature rise. After confirming that the pH of the aqueous layer was approximately 9-10, 96 g (3.0 mol) of paraformaldehyde (purity: 92%) was added in small portions over 1 hour. During this time, the temperature of the reaction system was confirmed to rise from 30°C to 45°C. The mixture was then air-cooled with stirring, and after confirming that the temperature had dropped to 30°C, stirring was continued at 30°C for 1 hour. After stirring was completed, 584 g of ethyl acetate and 211 g of 1,1-bis(4-hydroxyphenyl)cyclododecane were added to the flask. The temperature of the solution in the flask was then raised to 55°C, and the reaction was carried out for 32 hours. Because 1,1-bis(4-hydroxyphenyl)cyclododecane remained, the reaction was continued for another 4 hours at 60°C, and the disappearance of 1,1-bis(4-hydroxyphenyl)cyclododecane was confirmed. The temperature of the liquid in the flask was cooled to 40°C. Analysis of the reaction solution by GPC revealed that the proportion of benzoxazine compounds present in the reaction solution was 73 area%, with the remaining 27 area% being compounds with a higher molecular weight than the benzoxazine compounds (high molecular weight components). 400 g of pure water was mixed with the reaction-terminated liquid, stirred for 30 minutes, and allowed to stand to confirm separation from the organic layer, after which the aqueous layer was removed. This water washing procedure was repeated six times, and the pH of the aqueous layer was confirmed to be 7-8. The solvent was then removed by distillation under reduced pressure at 40°C. After distilling off the solvent, the mixture was cooled to obtain a non-flowable solid benzoxazine compound. Measurement of the resulting benzoxazine compound by GPC under the above analytical conditions revealed a purity of 70 area% and a high molecular weight component content of 30 area%. The obtained distillation residue was heated to 90°C, poured into a metal tray, cooled to room temperature, and crushed to obtain 308 g of a yellow solid benzoxazine compound. The amount of solvent contained in the solid was 9.9 wt %. The yield was 90 mol % based on the 1,1-bis(4-hydroxyphenyl)cyclododecane used. The obtained solid was １As a result of H-NMR analysis, peaks derived from cyclododecane were observed around 0.4 and 0.8 to 1.0 ppm, a peak derived from benzoxazine was observed around 3.3 to 4.0 ppm, a peak derived from allylamine was observed around 4.8 to 5.2 ppm, and a peak derived from aromatic compounds was observed around 6.6 to 7.3 ppm. １ The H-NMR spectrum is shown in Figure 2. From the analysis results, it was revealed that the compound was the target benzoxazine compound represented by formula (1-5).

[0039] Comparative Synthesis Example 1 (Synthesis of benzoxazine compound represented by formula (i)) A 500 mL four-neck flask equipped with a thermometer, stirrer, and condenser was charged with 19.5 g of water and 19.5 g of NaOH (granular) and stirred. 19.5 g of allylamine hydrochloride was added to this alkaline solution and stirred under a nitrogen atmosphere for 1 hour. 39.1 g of paraformaldehyde (purity: 92%) was then added in small portions and stirred for 5 hours. 93 g of ethyl acetate and 50 g of bisphenol F were added to this solution and stirred at 30-40°C for 13 hours. During the reaction, viscosity increased, so an additional 46 g of ethyl acetate was added. The disappearance of bisphenol F was confirmed by high-performance liquid chromatography (HPLC). Analysis of the reaction solution by GPC revealed that the proportion of the benzoxazine compound represented by formula (i) present in the reaction solution was 65 area %, with the remaining 35 area % being high molecular weight components. After completion of the reaction, the salt and unreacted paraformaldehyde were removed by filtration. The filtrate was washed five times with 50 mL of water. The washed filtrate was distilled under reduced pressure at 40°C to remove the solvent. The pressure during distillation was gradually reduced to a final pressure of 1.4 kPa. After the solvent was distilled off, the mixture was cooled to obtain 55 g of a fluid oily benzoxazine compound represented by formula (i). The amount of solvent contained in the oily product was 1.0 wt%. The obtained oily product was analyzed by GPC under the above analytical conditions, and the purity was 61 area% and the high molecular weight component content was 39 area%.

[0040] (Evaluation of storage stability) 5 g of the benzoxazine compounds represented by Formula (1-4), Formula (1-5), and Formula (i), obtained in Synthesis Examples 1 and 2 and Comparative Synthesis Example 1, respectively, were added to test tubes under atmospheric pressure and sealed. The test tubes containing the samples were then placed in a thermostatic chamber and heated at the temperature and for the time shown in Table 1 below. The purity before and after heating was measured by GPC, and the change in purity was calculated. The results are summarized in Table 1.

[0041] As shown in Table 1, the purity of the benzoxazine compound represented by formula (i) obtained in Comparative Synthesis Example 1 decreased by 5.4 area % after storage for 7 days at room temperature (30°C), compared to before heating, and decreased by 29.7 area % after storage for 7 hours at a higher temperature of 50°C. These results revealed that the benzoxazine compound represented by formula (i) undergoes a polymerization reaction during storage, resulting in a decrease in purity, and therefore presents challenges in handling it as a resin raw material. On the other hand, the purity of the compound of formula (1-4) obtained in Synthesis Example 1 did not change at room temperature (30°C) or at a higher temperature of 50°C, compared to before heating, demonstrating that it is possible to store it for a long period of time. Furthermore, the purity of the compound of formula (1-5) obtained in Synthesis Example 2 did not change at a high temperature of 50°C, compared to before heating, and changes were suppressed at room temperature (30°C), demonstrating that it is possible to store it for a long period of time. The benzoxazine resin composition of the present invention uses a benzoxazine compound having an allyl group, which can be stored for a long period of time even at room temperature and has good storage stability compared to conventionally known benzoxazine compounds represented by formula (i). This makes it easy to store and handle the raw materials used in producing the benzoxazine resin composition, facilitating industrial production.

[0042] Example 1: 15 g of the compound of formula (1-4) obtained in Synthesis Example 1 was used as resin component (A), 16.5 g of dicyclopentadiene-type epoxy resin (manufactured by Nippon Kayaku Co., Ltd.: product name "XD-1000") as resin component (B), and 0.64 g of triphenylphosphine (TPP) and 40.0 g of methyl ethyl ketone as component (D) were used, and the mixture was allowed to stand until completely dissolved. After complete dissolution, the solution was transferred to a tray and dried overnight in a draft, and then dried in a vacuum dryer at 60°C for 4 to 5 hours. The resulting composition was then placed in a mold (φ100 mm press mold) and cured in a heat press tester under conditions of 100°C / 1 hour and 130°C / 2 hours at 3 MPa. This was followed by post-curing in a hot air circulating oven at 140°C / 2 hours, 150°C / 2 hours, 160°C / 2 hours, and 180°C / 2 hours to obtain a cured product.

[0043] Comparative Example 1 A cured product was obtained in the same manner as in Example 1, except that 10.0 g of a novolac type curing agent (manufactured by Aica Kogyo Co., Ltd.: product name "BRG-555"), 24.0 g of a dicyclopentadiene type epoxy resin (manufactured by Nippon Kayaku Co., Ltd.: product name "XD-1000"), 0.64 g of triphenylphosphine, and 40.0 g of methyl ethyl ketone were used.

[0044] The glass transition temperature (Tg) and dielectric properties of the cured products obtained in Example 1 and Comparative Example 1 were evaluated under the above-mentioned analytical conditions. The results are summarized in Table 2.

[0045] It was confirmed that the cured product of the benzoxazine resin composition containing the compound of formula (1-4) obtained in Example 1 had good heat resistance (Tg) and dielectric properties. From the above, it became clear that the benzoxazine resin composition of the present invention has excellent heat resistance and dielectric properties and is therefore extremely useful as a resin material for prepregs, copper-clad laminates, printed circuit boards, sealants for semiconductors and electronic components, molded electrical and electronic components, automotive parts, laminates, paints, resist inks, and the like.

Claims

1. A benzoxazine resin composition comprising resin component (A) and resin component (B). Resin component (A): a benzoxazine compound represented by general formula (1) Resin component (B): an epoxy resin having a cyclic aliphatic structure. (In the formula, R １ each independently represents an alkylene group having 1 to 4 carbon atoms, and X represents a cycloalkylidene group having 5 to 20 carbon atoms.

2. The benzoxazine resin composition according to claim 1, wherein X in said general formula (1) is at least one selected from the group consisting of a cyclohexylidene group, a 3-methylcyclohexylidene group, a 4-methylcyclohexylidene group, a 3,3,5-trimethylcyclohexylidene group, and a cyclododecanylidene group.

3. The benzoxazine resin composition according to claim 1, wherein the content of said resin component (A) is in the range of 1% by weight or more and 99% by weight or less based on the total amount of the resin components.

4. The benzoxazine resin composition according to claim 1, wherein the resin component (B) is at least one selected from the group consisting of cycloalkylidene bisphenol type epoxy resins, dicyclopentadiene type epoxy resins, and alicyclic epoxy resins.

5. The benzoxazine resin composition according to claim 1, further comprising component (D): a curing accelerator.

6. A cured product of the benzoxazine resin composition according to claim 1.

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