Allyl group-containing alkoxy compound

Abstract

The present invention addresses the problem of providing a compound which is capable of being used as a novel curing agent, contributes to the improvement of dielectric properties, and prevents volatilization of the curing agent, which may cause deterioration in prepreg function, contamination of a prepreg production facility, and a decrease in the prepreg production yield. As a means of solving said problem, the present invention provides an allyl group-containing alkoxy compound represented by general formula (1). (In the formula, R1 each independently represent a C1-6 linear or C3-6 branched alkyl group, X represents a C5-20 cycloalkylidene group, n each independently represent 0 or an integer of 1-3, and m each independently represent an integer of 1-6.)

Description

Allyl group-containing alkoxy compounds

[0001] The present invention relates to a novel allyl-containing alkoxy compound having a cycloalkylidene skeleton, which, when used as a curing agent, is inhibited from volatilizing and contributes to improving dielectric properties.

[0002] Polyphenylene ether (PPE) is known to be suitable as a material for electronic devices such as printed wiring boards due to its low dielectric constant and low dielectric loss tangent. As a substrate material for printed wiring boards, properties such as flame retardancy and heat resistance have traditionally been required. Furthermore, polyphenylene ether resin is classified as a thermoplastic resin and is generally used in combination with a curing agent. It is considered desirable to add triallyl isocyanurate, a general-purpose curing agent, in a large amount of 30% by weight or more to the polyphenylene ether resin. However, because it is volatile around 150°C, the curing temperature of polyphenylene ether resin, the curing agent volatilizes during thermal curing of the polyphenylene ether resin, preventing the curing performance equivalent to the added amount from being achieved and causing problems such as contamination of the manufacturing equipment. When triallyl isocyanurate is used as a curing agent for polyphenylene ether, if the amount of triallyl isocyanurate used as a curing agent is reduced, the crosslinking portions required for curing the resin are reduced. In addition, the triallyl isocyanurate involved in crosslinking is further reduced due to volatilization of the triallyl isocyanurate. This has reaffirmed the problem that the polyphenylene ether resin cannot be sufficiently cured, and a cured product with the desired properties cannot be obtained (Patent Document 1).

[0003] International Publication No. 2023 / 089982

[0004] The present invention has been made in light of the above-mentioned circumstances, and an object of the present invention is to provide a compound that can serve as a novel curing agent that suppresses the volatilization of the curing agent, which is a factor in reducing the functionality of the prepreg and contaminating the production equipment, as well as reducing the production yield of the prepreg, and that also contributes to improving the dielectric properties.

[0005] The present inventors have previously reported that a cured product having excellent dielectric properties can be obtained by using a compound having a bisphenol skeleton, the hydroxyl group of which is modified with an alkyl group, and an allyl group as a curing agent for curing a polyphenylene ether resin (Japanese Patent Application No. 2023-201284). However, the dielectric properties were not fully satisfactory, and as a result of further intensive research, the present inventors discovered that a compound having an alicyclic bisphenol skeleton can produce a cured product having excellent dielectric properties, thereby completing the present invention.

[0006] The present invention is as follows: 1. An allyl group-containing alkoxy compound represented by general formula (1): (In the formula, R １ each independently represent a linear alkyl group having 1 to 6 carbon atoms or a branched alkyl group having 3 to 6 carbon atoms, X represents a cycloalkylidene group having 5 to 20 carbon atoms, each n independently represents 0 or an integer of 1 to 3, and each m independently represents an integer of 1 to 6. 2. The allyl group-containing alkoxy compound according to 1., wherein X is 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), or a cyclododecanylidene group (12 carbon atoms). 3. The allyl group-containing alkoxy compound according to 1., which is any one of the compounds represented by chemical formulas (1-1) to (1-6). 4. A polyphenylene ether resin curing agent comprising the allyl group-containing alkoxy compound according to 1. 5. A method for curing a polyphenylene ether resin with a curing agent comprising an allyl group-containing alkoxy compound represented by general formula (1). (In the formula, R １ each independently represents a linear alkyl group having 1 to 6 carbon atoms or a branched alkyl group having 3 to 6 carbon atoms; X represents a cycloalkylidene group having 5 to 20 carbon atoms; each n independently represents 0 or an integer of 1 to 3; and each m independently represents an integer of 1 to 6.

[0007] The allyl group-containing alkoxy compound represented by the general formula (1) of the present invention has low volatility, and therefore, when used as a curing agent for curing a polyphenylene ether resin, problems such as equipment contamination due to volatilization of the curing agent can be reduced, which is very beneficial in terms of yield and production efficiency. Furthermore, when the allyl group-containing alkoxy compound represented by the general formula (1) of the present invention is used as a curing agent for curing a polyphenylene ether resin, the resulting resin has improved dielectric properties, making it industrially very useful.

[0008] The present invention will be described in detail below. The compound of the present invention is an allyl group-containing alkoxy compound represented by general formula (1). (In the formula, R １ each independently represents a linear alkyl group having 1 to 6 carbon atoms or a branched alkyl group having 3 to 6 carbon atoms; X represents a cycloalkylidene group having 5 to 20 carbon atoms; each n independently represents 0 or an integer of 1 to 3; and each m independently represents an integer of 1 to 6.

[0009] R in general formula (1) １ are each independently a linear alkyl group having 1 to 6 carbon atoms or a branched alkyl group having 3 to 6 carbon atoms. Among these, it is preferable that each independently be a linear alkyl group having 1 to 4 carbon atoms or a branched alkyl group having 3 or 4 carbon atoms. １X in general formula (1) represents a cycloalkylidene group having 5 to 20 carbon atoms, and may contain an alkyl group as a branched chain as long as the number of carbon atoms is within the range of 5 to 20. Among these, 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 of X in general formula (1) 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 cyclohexylidene group (6 carbon atoms), 3,3,5-trimethylcyclohexylidene group (9 carbon atoms), and cyclododecanylidene group (12 carbon atoms), and particularly preferred are cyclohexylidene group (6 carbon atoms) and 3,3,5-trimethylcyclohexylidene group (9 carbon atoms).

[0010] In the general formula (1), n's each independently represent 0 or an integer of 1 to 3. Among these, each independently is preferably 0, 1 or 2, more preferably 0 or 1, and particularly preferably 0. When n in the general formula (1) is 1, R１ The substitution position of the alkoxy group "-OC" on the benzene ring is ｍ H ２ｍ＋１ In general formula (1), m each independently represents an integer of 1 to 6. Among them, an integer of 1 to 4 is preferred, 1, 2 or 3 is more preferred, 1 or 2 is even more preferred, and 1 is particularly preferred. ｍ H ２ｍ＋１ The group may be linear, and when m is 3, 4, 5 or 6, may additionally be branched. ｍ H ２ｍ＋１ Regarding the group, specific examples of linear groups include a methyl group, an ethyl group, an n-propyl group, and an n-butyl group, and specific examples of branched groups include an isopropyl group, an isobutyl group, a tert-butyl group, and a sec-butyl group. ｍ H ２ｍ＋１ The group is preferably any of the groups exemplified above, more preferably a methyl group, an ethyl group, an n-propyl group, or an isopropyl group, still more preferably a methyl group or an ethyl group, and particularly preferably a methyl group.

[0011] Specific examples of the allyl group-containing alkoxy compound represented by general formula (1) include compounds (1-1) to (1-6) having the following chemical structures:

[0012] <Method for producing the compound of the present invention> There are no particular limitations on the starting materials and production method for the allyl group-containing alkoxy compound represented by general formula (1) of the present invention. As a method for synthesizing the allyl group-containing alkoxy compound represented by general formula (1), for example, an allyl etherification step in which a bisphenol compound represented by general formula (2) and an allyl halide represented by general formula (3) are reacted in the presence of a basic catalyst to synthesize an allyl ether compound represented by general formula (4), then a rearrangement reaction step in which the allyl ether group of the allyl ether compound represented by general formula (4) is subjected to a Claisen rearrangement reaction to synthesize an allyl group-containing hydroxy compound represented by general formula (5), and further an alkoxylation step in which the allyl group-containing hydroxy compound represented by general formula (5) is reacted with an alkoxylating agent to synthesize the allyl group-containing alkoxy compound represented by general formula (1). (R in general formulas (2), (4) and (5) １ , X and n are defined as in general formula (1), and in general formula (3), Y represents a halogen atom.

[0013] For example, in the case of compound (1-2), as illustrated in the following reaction formula, compound (2-2) (1,1-bis(4-hydroxy-3-methylphenyl)-3,3,5-trimethylcyclohexane), a bisphenol compound represented by general formula (2), is reacted with allyl bromide, an allyl halide represented by general formula (3), to obtain compound (4-2), a compound represented by general formula (4). Next, compound (4-2) is subjected to a rearrangement reaction to obtain compound (5-2), a compound represented by general formula (5). Thereafter, compound (5-2) is reacted with methyl iodide as an alkoxylating agent to synthesize the target compound (1-2). An example of such a synthesis method will be described in detail below as a method for producing a compound represented by general formula (1) of the present invention.

[0014] <Allyl Etherification Step> An allyl ether compound represented by general formula (4) can be synthesized by an allyl etherification step in which a bisphenol compound represented by general formula (2) is reacted with an allyl halide represented by general formula (3).

[0015] <Bisphenol compound represented by general formula (2)> R in general formula (2) １ The definitions and preferred embodiments of X, n, and n are the same as those of general formula (1). Specific examples of the compound represented by general formula (2) include compounds represented by chemical formulas (2-1) to (2-4), and these compounds are preferred.

[0016] <Allyl Halide Represented by General Formula (3)> The allyl halide represented by general formula (3) is not particularly limited, and generally, allyl chloride, allyl bromide, allyl iodide, etc. are preferably used, with allyl chloride or allyl bromide being particularly preferred. In this production method, the amount of the allyl halide represented by general formula (3) used is preferably in the range of 1 to 10 equivalents, more preferably in the range of 1 to 5 equivalents, and even more preferably in the range of 1 to 3 equivalents, relative to one hydroxy group of the bisphenol compound represented by general formula (2).

[0017] In the allyl etherification reaction step, the reaction is preferably carried out in the presence of a basic catalyst to capture the hydrogen halide produced. Examples of basic catalysts that can be used include inorganic bases such as sodium hydride, sodium carbonate, potassium carbonate, sodium hydroxide, and potassium hydroxide. If necessary, the reaction may be carried out in the presence of a co-catalyst such as an alkali metal bromide salt such as sodium bromide and potassium bromide, an alkali metal iodide salt such as sodium iodide and potassium iodide, ammonium bromide, or ammonium iodide. The basic catalyst and co-catalyst are not limited to these. The amount of the basic catalyst used is preferably in the range of 1 to 10 equivalents, more preferably 1 to 5 equivalents, and even more preferably 1 to 3 equivalents, relative to one hydroxy group of the compound represented by general formula (2).

[0018] The allylic etherification reaction step 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, and examples include alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, and sec-butyl alcohol; cyclic alkanes such as cyclopentane, cyclohexane, and cycloheptane; ethers such as diethyl ether, diisopropyl ether, tetrahydrofuran, and dioxane; ketones such as acetone, diethyl ketone, methyl n-butyl ketone, and methyl isobutyl ketone; esters such as ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, and isobutyl acetate; nitriles such as acetonitrile; and amides such as N,N-dimethylformamide and N-methylpyrrolidone. 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, and is typically in the range of 0.5 to 5 times by weight, preferably 1 to 3 times by weight, relative to the compound represented by formula (2).

[0019] During the allyl etherification reaction step, the reaction temperature is usually in the range of 0 to 120°C, preferably in the range of 10 to 80°C, and more preferably in the range of 20 to 70°C. If the reaction temperature is too high, by-products increase and the yield decreases, while if the reaction temperature is too low, the reaction rate slows. The reaction pressure may be normal, elevated, or reduced. After completion of the reaction, the compound represented by general formula (4) can be obtained from the resulting reaction mixture by known methods. For example, after the reaction, the oil phase solution can be mixed with an organic solvent that dissolves the reaction product and separates from water, such as toluene, xylene, or methyl isobutyl ketone, and the oil phase solution can be washed with water, or the remaining raw materials and solvent can be distilled off from the reaction mixture to obtain the target product as a residual liquid.

[0020] <Allyl ether compound represented by general formula (4)> R in general formula (4) １The definitions and preferred embodiments of X, n, and n are the same as those of general formula (1). Specific examples of the compound represented by general formula (4) include compounds represented by chemical formulas (4-1) to (4-4), and these compounds are preferred.

[0021] <Rearrangement Reaction Step> An allyl group-containing hydroxy compound represented by general formula (5) can be synthesized by a rearrangement reaction step in which the allyl ether group of the allyl ether compound represented by general formula (4) is subjected to a Claisen rearrangement reaction.

[0022] (Rearrangement Reaction Conditions) The rearrangement reaction step can be carried out in accordance with known methods for synthesizing an allyl group-containing aromatic hydroxy compound by the Claisen rearrangement reaction of an aromatic allyl ether compound (e.g., International Publication No. 2019 / 019481, etc.). Specifically, the Claisen rearrangement reaction can be carried out, for example, by heating to a temperature of 180°C to 220°C. The rearrangement reaction step is preferably carried out under an inert gas atmosphere such as nitrogen, argon, or helium. The rearrangement reaction step may or may not involve the use of a solvent. If a solvent is used, there are no limitations as long as it is inert to the reaction and dissolves the allyl ether compound represented by general formula (4). Examples of suitable solvents include N-methylpyrrolidone, dimethyl sulfoxide, dimethylformamide, dimethylaniline, diethylaniline, 1,2-dichlorobenzene, and tetralin. After completion of the reaction, the resulting reaction mixture can be used to obtain the compound represented by general formula (4) from this mixture by known methods. For example, after the reaction, the target product can be obtained as a residual liquid by mixing an organic solvent that dissolves the reaction product and separates from water, such as toluene, xylene, or methyl isobutyl ketone, and then washing the oil phase solution with water, or by distilling off the remaining raw materials and solvent from the reaction mixture. The rearrangement reaction step is preferably carried out in the presence of a phenolic antioxidant in order to promote the rearrangement reaction.Specific examples of the phenolic antioxidant that can be used include methylhydroquinone, tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, 2,5-di-tert-amylhydroquinone, 2,2-bis(4-hydroxy-3-tert-butylphenyl)propane, 2,2-bis(4-hydroxy-3,5-di-tert-butylphenyl)propane, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 4,4'-ethylidenebis(3-methyl Examples of suitable antioxidants include, but are not limited to, 4,4'-methylenebis(2,6-di-tert-butylphenol), 4,4'-butylidenebis(3-methyl-6-tert-butylphenol), 4,4'-thiobis(3-methyl-6-tert-butylphenol), 1,1,3-tris-(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, and 1,1-bis(4-hydroxyphenyl)-cyclohexane. These antioxidants may be used alone or in combination. The amount of the phenolic antioxidant used in the rearrangement reaction step is preferably in the range of 0.001 to 0.2 times by weight, and more preferably in the range of 0.001 to 0.1 times by weight, relative to the allyl ether compound represented by general formula (5).

[0023] <Allyl group-containing hydroxy compound represented by general formula (5)> R in general formula (5) １ The definitions and preferred embodiments of X, n, and n are the same as those of general formula (1). Specific examples of the compound represented by general formula (5) include compounds represented by chemical formulas (5-1) to (5-4), and these compounds are preferred.

[0024] <Alkoxylation Step> The allyl group-containing alkoxy compound represented by general formula (1) can be synthesized by the alkoxylation step in which the allyl group-containing hydroxy compound represented by general formula (5) is reacted with an alkoxylating agent.

[0025] <Alkoxylating Agent> Any alkylating agent used in a reaction to alkylate a hydroxy group can be used to alkoxylate by applying a known method, and specific examples thereof include halogenated alkanes. Specific examples include methyl chloride, ethane chloride, propane chloride, butane chloride, methane bromide, ethane bromide, propane bromide, butane bromide, methane iodide, ethane iodide, propane iodide, and butane iodide. The amount of alkylating agent used is preferably in the range of 1 to 3 equivalents, more preferably 1 to 2 equivalents, and even more preferably 1 to 1.5 equivalents, relative to one hydroxy group in the allyl group-containing hydroxy compound represented by general formula (5) used.

[0026] When a halogenated alkane is used, the alkoxylation reaction step is carried out in the presence of a basic substance. The basic substance is preferably an inorganic base, and is preferably any one or a combination of two or more of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate. The amount of the basic substance used is preferably in the range of 1 to 1.4 equivalents per hydroxy group of the allyl group-containing hydroxy compound represented by general formula (5) used.

[0027] When a halogenated alkane is used, the alkoxylation reaction step may be carried out in the presence of a phase transfer catalyst. The phase transfer catalyst is, for example, a quaternary ammonium salt-based phase transfer catalyst, and specific examples thereof include tetrabutylammonium chloride, tetrabutylammonium bromide, benzyltriethylammonium chloride, tetrabutylammonium chloride, trioctylmethylammonium chloride, dodecyltrimethylammonium chloride, and tetradecylbromotrimethylammonium chloride, and a combination of two or more of these are preferred. The amount of the phase transfer catalyst added is preferably in the range of 0.1 to 5 wt % of the weight of the allyl group-containing hydroxy compound represented by general formula (5) used.

[0028] The solvent used in the alkoxylation reaction when a halogenated alkane is used is one or more of an alcohol solvent, an aromatic hydrocarbon solvent, a ketone solvent, an ether solvent, or a halogenated solvent, and is preferably one or more of ethanol, propanol, butanol, toluene, xylene, acetone, methyl isobutyl ketone, dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, dimethyl ether, dichloromethane, and chloroform. The amount of the solvent used is preferably in the range of 2 to 5 times by weight relative to the mass of the allyl group-containing hydroxy compound represented by general formula (5) used.

[0029] When a halogenated alkane is used, the alkoxylation reaction step is preferably carried out at a temperature in the range of 30 to 90° C. The reaction time varies depending on reaction conditions such as the type and amount of the substrate used and the temperature, but is usually in the range of 1 to 30 hours.

[0030] After the reaction is completed, the resulting reaction mixture can be used to obtain the compound represented by general formula (1) by a known method. For example, after the reaction, the target product can be obtained as a residual liquid by mixing an organic solvent that dissolves the reaction product and separates it from water, such as toluene, xylene, or methyl isobutyl ketone, and then washing the oil phase solution with water, or by distilling off the remaining raw materials and solvent from the reaction mixture.

[0031] The allyl group-containing alkoxy compound of the present invention represented by the general formula (1) can be used as a curing agent for polyphenylene ether resins as described below. In addition, since it has an allyl group, it can also be used as a raw material for bismaleimide resins, a raw material for curable resins that are cured by an enethiol reaction with a polythiol compound, and the like.

[0032] <Polyphenylene Ether Resin Curing Agent> The polyphenylene ether resin curing agent of the present invention contains the allyl group-containing alkoxy compound represented by general formula (1) of the present invention, thereby enabling the production of a cured product with improved dielectric properties compared to conventional curing agents. The polyphenylene ether resin curing agent of the present invention may use one of the allyl group-containing alkoxy compounds represented by general formula (1) or a combination of two or more of them. The polyphenylene ether resin curing agent preferably contains only the allyl group-containing alkoxy compound represented by general formula (1), but may contain other curing agents other than the allyl group-containing alkoxy compound represented by general formula (1) as long as the effects of the present invention are not impaired. Examples of such curing agents include trialkenyl isocyanurate compounds, polyfunctional allyl compounds having two or more allyl groups in the molecule other than the allyl group-containing alkoxy compound represented by general formula (1), polyfunctional allyl ether compounds having two or more allyl ether groups in the molecule, polyfunctional (meth)acrylate compounds having two or more (meth)acrylic groups in the molecule, and polyfunctional vinyl compounds. When the polyphenylene ether resin curing agent of the present invention contains a curing agent other than the allyl group-containing alkoxy compound represented by general formula (1), the allyl group-containing alkoxy compound represented by general formula (1) accounts for preferably 50 wt% to 99 wt%, more preferably 60 wt% to 99 wt%, even more preferably 70 wt% to 99 wt%, and particularly preferably 80 wt% to 99 wt% of the entire polyphenylene ether resin curing agent. The polyphenylene ether resin cured by the polyphenylene ether resin curing agent of the present invention is component (A) in the curable resin composition described below.

[0033] <Curable Resin Composition> The allyl group-containing alkoxy compound represented by general formula (1) of the present invention can be used in a curable resin composition containing a polyphenylene ether resin as component (A) and a curing agent containing at least an allyl group-containing alkoxy compound represented by general formula (1) as component (B). When the curable resin composition contains components (A) and (B) and, optionally, components (C) and (D) described below, it is preferably in an embodiment consisting of any one of components (A) and (B), components (A), (B), and (C), or components (A), (B), (C), and (D). <Component (A)> The polyphenylene ether resin that can be used as component (A) is not particularly limited, but polyphenylene ethers having repeating units represented by general formula (6) are preferred, and polyphenylene ethers having repeating units represented by general formula (6-1) are more preferred. (In the formula, R ５ each independently represents a linear alkyl group having 1 to 6 carbon atoms or a branched alkyl group having 3 to 6 carbon atoms, a cyclic alkyl group having 5 or 6 carbon atoms, a phenyl group, or a halogen atom; each p independently represents 0, 1, 2, or 3; and each q independently represents an integer of 1 or greater. (In the formula, the definition of q is the same as in general formula (6).)

[0034] Specific examples of the polyphenylene ether resin that is component (A) include poly(2,6-dimethyl-1,4-phenylene ether), poly(2-methyl-6-ethyl-1,4-phenylene ether), poly(2-methyl-6-phenyl-1,4-phenylene ether), poly(2,6-dichloro-1,4-phenylene ether), copolymers of 2,6-dimethylphenol and other phenols (e.g., 2,3,6-trimethylphenol, 2-methyl-6-butylphenol, etc.), polyphenylene ether copolymers obtained by coupling 2,6-dimethylphenol with biphenols, bisphenols, or trisphenols, and polyphenylene ether copolymers obtained by coupling 2,6-dimethylphenol and other phenols (e.g., 2,3,6-trimethylphenol, 2-methyl-6-butylphenol, etc.) with biphenols, bisphenols, or trisphenols. Further examples include polyphenylene ethers in which the terminal hydroxy groups of these polyphenylene ethers have been modified with functional groups having unsaturated double bonds, such as allyl ether, acryloyl, methacryloyl, vinyl ether, etc. For example, polyphenylene ethers that are (meth)acrylated terminal compounds of copolymers of 2,6-dimethylphenol and 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane can be used.Among these, the polyphenylene ether that can be used as component (A) is preferably a polyphenylene ether modified with a functional group having an unsaturated double bond, and more preferably a compound of a polyphenylene ether copolymer obtained by coupling 2,6-dimethylphenol with a biphenol, bisphenol, or trisphenol, modified with a functional group having an unsaturated double bond, or a compound of a polyphenylene ether copolymer obtained by coupling 2,6-dimethylphenol and other phenols (e.g., 2,3,6-trimethylphenol, 2-methyl-6-butylphenol, etc.) with a biphenol, bisphenol, or trisphenol, modified with a functional group having an unsaturated double bond, More preferred are (meth)acrylated terminal compounds of polyphenylene ether copolymers obtained by coupling 2,6-dimethylphenol with biphenols, bisphenols, or trisphenols, and (meth)acrylated terminal compounds of polyphenylene ether copolymers obtained by coupling 2,6-dimethylphenol and other phenols (e.g., 2,3,6-trimethylphenol, 2-methyl-6-butylphenol, etc.) with biphenols, bisphenols, or trisphenols, and particularly preferred are (meth)acrylated terminal compounds of copolymers of 2,6-dimethylphenol and 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane.

[0035] <Component (B)> The component (B) curing agent in the curable resin composition contains at least an allyl group-containing alkoxy compound represented by general formula (1). The component (B) curing agent preferably contains only the allyl group-containing alkoxy compound represented by general formula (1), but may contain other curing agents other than the allyl group-containing alkoxy compound represented by general formula (1) as long as the effects of the present invention are not impaired. Examples of curing agents other than the allyl group-containing alkoxy compound represented by general formula (1) that can be used as the curing agent for component (B) include trialkenyl isocyanurate compounds, allyl group-containing alkoxy compounds other than the allyl group-containing alkoxy compound represented by general formula (1), polyfunctional allyl ether compounds having two or more allyl ether groups in the molecule, polyfunctional (meth)acrylate compounds having two or more (meth)acrylic groups in the molecule, and polyfunctional vinyl compounds. When the curing agent for component (B) contains a curing agent other than the allyl group-containing alkoxy compound represented by general formula (1), the allyl group-containing alkoxy compound represented by general formula (1) preferably accounts for 50% by weight to 99% by weight of the entire curing agent for component (B), more preferably 60% by weight to 99% by weight, even more preferably 70% by weight to 99% by weight, and particularly preferably 80% by weight to 99% by weight. The content of component (B) in the curable resin composition is preferably in the range of 1.0 to 10.0 parts by weight, more preferably 2.0 to 8.0 parts by weight, and particularly preferably 3.0 to 5.5 parts by weight, per 100 parts by weight of component (A).

[0036] <Component (C)> The curable resin composition preferably contains a reaction initiator as component (C) in addition to component (A) and component (B). Component (C) is added to promote the crosslinking reaction of the curable resin composition containing component (A) and component (B). Component (C) is not particularly limited as long as it promotes the crosslinking reaction, and examples thereof include ionic catalysts such as imidazoles, tertiary amines, quaternary ammonium salts, boron trifluoride amine complexes, organophosphines, and organophosphonium salts, and radical polymerization initiators such as organic peroxides, hydroperoxides, and azoisobutyronitrile. Among these, it is preferable to use an organic peroxide. Examples of organic peroxides include aliphatic organic peroxides such as di-t-butyl peroxide, dilauroyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,2-bis(t-butylperoxy)butane, 2,2-bis(t-butylperoxy)octane, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne, and di-n-propyl peroxydicarbonate; dibenzoyl peroxide, dicumyl peroxide, and t-butyl peroxybenzyl; Examples of aromatic organic peroxides include aromatic organic peroxides containing an aromatic ring, such as dicumyl peroxide, t-amyl peroxybenzoate, t-butylcumyl peroxide, bis(1-t-butylperoxy-1-methylethyl)benzene, 2-phenyl-2-[(2-phenylpropan-2-yl)peroxy]propane, α,α'-di(t-butylperoxy)diisopropylbenzene, α,α'-bis(t-butylperoxy-m-isopropyl)benzene, and di-t-butylperoxyisophthalate. Among these, aromatic organic peroxides are preferably used. As aromatic organic peroxides, dicumyl peroxide, t-butylcumyl peroxide, bis(1-t-butylperoxy-1-methylethyl)benzene, and 2-phenyl-2-[(2-phenylpropan-2-yl)peroxy]propane are more preferred, and 2-phenyl-2-[(2-phenylpropan-2-yl)peroxy]propane is particularly preferred. The component (C) may be used alone or in combination of two or more.The content of component (C) is preferably in the range of 0.05 to 0.9 parts by weight, more preferably in the range of 0.15 to 0.8 parts by weight, even more preferably in the range of 0.3 to 0.7 parts by weight, and particularly preferably in the range of 0.35 to 0.6 parts by weight, per 100 parts by weight of component (A).

[0037] <Component (D)> The curable resin composition preferably contains a filler as component (D) in addition to component (A), component (B), and, if necessary, component (C). Component (D) is not particularly limited as long as it is a filler typically used in curable resin compositions, and for example, inorganic fillers such as silicon oxide, aluminum oxide, magnesium oxide, boron nitride, aluminum nitride, silicon nitride, silicon carbide, and hexagonal boron nitride can be mixed and used. The content of component (D) is preferably in the range of 10 to 150 parts by weight, and more preferably in the range of 10 to 100 parts by weight, per 100 parts by weight of the total amount of components (A) and (B), or components (A), (B), and (C).

[0038] The method for preparing the curable resin composition is not particularly limited, and examples thereof include a method of mixing the above-mentioned components and mixing or dispersing them using a stirrer, and a method of uniformly dissolving or dispersing each component in a solvent and then volatilizing the used solvent.

[0039] The cured product of the curable resin composition refers to a cured product (cured prepreg) obtained by semi-curing (B-stage) the cured product (prepreg) of the above-mentioned curable resin composition, optionally further mixing with reinforcing fibers typically used in prepregs as component (E), and further curing (C-stage) the resulting cured product (prepreg). Examples of the reinforcing fibers of component (E) include various inorganic or organic fibers such as carbon fiber, aramid fiber, nylon fiber, high-strength polyester fiber, glass fiber, boron fiber, alumina fiber, and silicon nitride fiber. Among these, carbon fiber, aramid fiber, glass fiber, boron fiber, alumina fiber, and silicon nitride fiber are preferred from the viewpoint of specific strength and specific elasticity. Glass fiber is preferred from the viewpoint of insulation. The thickness of the fiber substrate is preferably 0.3 mm or less, more preferably 0.15 mm or less, and even more preferably 0.1 mm or less. Component (E) may be used alone or in combination of two or more types.

[0040] The method for producing the prepreg is not particularly limited, and known prepreg production methods can be used. For example, the curable resin composition described above can be mixed with a varnish containing a solvent (component (F)), and optionally with reinforcing fibers (component (E)). The varnish is then cast onto a support such as a polyimide or polyester film or a glass substrate, and heated and dried as needed to semi-cure (B-stage). Examples of methods for mixing the varnish and reinforcing fibers (component (E)) include applying the varnish to the reinforcing fibers (component (E)) and impregnating them. Other prepreg production methods include filling the curable resin composition described above into a mold or the like, or heating and melting it and injecting it into a mold, and then heating it to a predetermined temperature to cure it. The heating temperature (semi-cure temperature) used for semi-cure (B-stage) is preferably a temperature above the boiling point of the solvent, which provides good solvent removal efficiency, since drying is performed simultaneously. Specifically, the temperature is preferably in the range of 80 to 200°C, more preferably in the range of 140 to 180°C.

[0041] <Component (F)> The component (F) solvent that can be used when preparing the varnish of the curable resin composition described above is not particularly limited as long as it dissolves or disperses the curable resin composition, but examples include aromatic compounds such as toluene and xylene, ketone compounds such as methyl ethyl ketone, cyclopentanone, and cyclohexanone, and chlorine-based organic solvents such as chloroform. Among these, aromatic compounds such as toluene and xylene, and ketone compounds such as methyl ethyl ketone, cyclopentanone, and cyclohexanone are preferred, aromatic compounds such as toluene and xylene are more preferred, and toluene is particularly suitable. It is preferable to contain 50 to 200 parts by weight of component (F) per 100 parts by weight of the curable resin composition, and more preferably 70 to 150 parts by weight.

[0042] The prepreg is heated to a predetermined temperature for further curing (C-staging), whereby a cured product of the curable resin composition (cured prepreg) can be produced. The curing temperature can be appropriately determined within the range of 105 to 270°C.

[0043] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The analytical methods used in the present invention are as follows. <Analytical Method> (1) Purity Analysis (Analytical Values ​​are Area Percentages) Measuring 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 Mobile Phase: (A) 0.1% by Volume Acetic Acid Aqueous Solution, (B) Methanol Gradient Conditions: (A) Volume % (Time from Start of Analysis) 50% (0 min) → 100% (7.5 min) → 100% (20 min) Sample Injection Volume: 5 μL Detection Wavelength: 280 nm

[0044] (2) Evaluation of heat resistance of curing agent: 5% weight loss temperature measurement The heat resistance of the compounds used as curing agents was evaluated by measuring the 5% weight loss temperature of each compound using the following apparatus and conditions: Apparatus: DTG-60A / Shimadzu Corporation Temperature: 30 to 400°C (heating rate 10°C / min.) Measurement atmosphere: open, nitrogen 50 mL / min. Sample weight: 8 to 12 mg Sample container material: aluminum

[0045] (3) Evaluation of Dielectric Properties of Cured Resin Composition The dielectric constant and dielectric loss tangent of a resin film obtained by curing the resin composition were measured using the following device under the following conditions: Device: Cavity resonator manufactured by AET Corporation Sample size: 500 mm x 500 mm Frequency: 10 GHz Mode: TE Measurement temperature: 25°C Furthermore, the dielectric loss of an electric signal was calculated as (proportionality constant) x (frequency) x (dielectric constant). ０．５ × (dielectric loss tangent) × (dielectric loss tangent) calculated from the dielectric constant and dielectric loss tangent measured at a frequency of 10 GHz. ０．５ The value of × (dielectric loss tangent) was calculated. ０．５ The lower the value of × (dielectric loss tangent), the smaller the dielectric loss and the better the dielectric properties.

[0046] Example 1: Production of compound (1-2) (1) Production of compound (4-2) by allylic etherification reaction step 25.8 g of compound (2-2), 31.2 g of potassium carbonate, and 126.7 g of dimethylformamide (DMF) were charged into a four-neck flask, and while maintaining the temperature at 60°C, 35.7 g of allyl bromide was slowly added dropwise. After the completion of the addition, the mixture was stirred at the same reaction temperature for 22 hours. 26.1 g of potassium carbonate and 46.0 g of allyl bromide were then added, and the mixture was stirred for an additional 24 hours. After the reaction was completed, 51.1 g of toluene as a solvent and 102.2 g of water to wash the oil layer were added and stirred, and after standing, the aqueous layer was removed. 73.0 g of water was added to the obtained oil layer, and the mixture was stirred. After standing, the aqueous layer was removed. This operation was repeated twice. The solvent from the obtained oil layer was removed by distillation under reduced pressure to obtain oily compound (4-2). Yield: 92.3%. Mass spectrometry. １The results of H-NMR analysis confirmed that the target compound (4-2) was obtained. Molecular weight of compound (4-2) (mass spectrometry / electrospray ionization): 419.0 (M+H) ＋ １ H-NMR (400MHz, CDCl ３ / TMS): δ 0.35 (s, 3H), 0.85 (t, J = 12.5 Hz, 1H), 0.95 (d, J = 6.6 Hz, 3H), 0.97 (s, 3H), 1.10 (t, J = 12.4 Hz, 1H), 1.35 (d, J = 12.7 Hz, 1H), 1.87 (d, J = 13.5 Hz, 1H), 1.93-2.04 (m, 1H), 2.17 (s, 3H), 2.20 (s, 3H), 2.40 (d, J = 13.5 Hz, 1H), 2.63 (d, J = 12.7 Hz, 1H), 4.45 (d, J = 5.0 Hz, 2H), 4.49 (d, J = 5.0 Hz, 2H), 5.24 (t, J = 10.4 Hz, 2H), 5.40 (t, J = 17.1 Hz, 2H), 5.98-6.11 (m, 2H), 6.63 (d, J = 8.6 Hz, 2H), 6.69 (d, J = 8.5 Hz, 2H), 6.92 (d, J = 8.6 Hz, 2H), 7.00 (s, 1H), 7.05 (s, 1H), 7.09 (d, 1H). The purity of the obtained compound (4-2) by the above analytical method was 99.1%.

[0047] (2) Preparation of compound (5-2) by rearrangement reaction step 5.0 g of compound (4-2), 75.9 g of N-methylpyrrolidone (NMP), and 0.02 g of tert-butylhydroquinone were placed in a 100 mL test tube, the atmosphere in the test tube was replaced with nitrogen gas, and the mixture was stirred at 200°C for 20 hours. After the reaction was completed, the mixture was cooled to room temperature, and 60.0 g of toluene and 77.3 g of water were added to wash the oil layer and stirred. After standing, the aqueous layer was removed. Furthermore, 50.0 g of water was added to the obtained oil layer and stirred, and the oil layer was removed after standing. This operation was repeated several times, and the oil layer was washed with water. The solvent in the obtained oil layer was removed by distillation under reduced pressure, and the oil was allowed to stand at room temperature overnight, yielding compound (5-2) as a pale yellow solid. Yield: 94.7% Mass spectrometry １ ​The results of H-NMR analysis confirmed that the target compound (5-2) was obtained. Molecular weight of compound (5-2) (mass spectrometry / electrospray ionization): 417.9 (M−H) － １ H-NMR (400MHz, CDCl ３ / TMS): δ 0.36 (s, 3H), 0.84 (t, J = 12.5 Hz, 1H), 0.95 (d, J = 6.7 Hz, 3H), 0.96 (s, 3H), 1.08 (t, J = 12.3 Hz, 1H), 1.35 (d, J = 12.7 Hz, 1H), 1.83 (d, J = 13.5 Hz, 1H), 1.90-2.00 (m, 1H), 2.15 (s, 3H), 2.20 (s, 3H), 2.38 (d, J = 13.8 Hz, 1H), 2.61 (d, J = 13.9 Hz, 1H), 3.32-3.37 (m, 4H), 4.76 (s, 1H), 4.81 (s, 1H), 5.07-5.17 (m, 4H), 5.92-6.05 (m, 2H), 6.78 (s, 1H), 6.84 (s, 1), 6.89 (s, 1H), 6.94 (s, 1H). The purity of the obtained compound (5-2) according to the above analytical method was 94.7%.

[0048] (3) Preparation of compound (1-2) by alkoxylation process 1.1 g of compound (5-2), 0.8 g of 48% NaOH aqueous solution, and 1.1 g of acetone were placed in a test tube and stirred at room temperature for 30 minutes. Then, 1.2 g of methyl iodide was added, heated to 40°C, and stirred for 2 hours. After the reaction was completed, 10 g of toluene as a solvent and 10 g of water to wash the oil layer were added and stirred, and after standing, the aqueous layer was removed. 2.0 g of water was added to the obtained oil layer, stirred, and after standing, the aqueous layer was removed. This operation was repeated three times. The solvent from the obtained oil layer was removed by distillation under reduced pressure, and oily compound (1-2) was obtained in a yield of 89.4%. Mass spectrometry １ The results of H-NMR analysis confirmed that the target compound (1-2) was obtained. Molecular weight of compound (1-2) (mass spectrometry / electrospray ionization): 447.3 (M+H) ＋ １ H-NMR (400MHz, CDCl ３ ​​ / TMS): δ 0.35 (s, 3H), 0.84 (t, J = 12.5 Hz, 1H), 0.95-0.96 (m, 6H), 1.08 (t, J = 12.3 Hz, 1H), 1.34 (d, J = 11.3 Hz, 1H), 1.80 (d, J = 13.6 Hz, 1H), 1.89-1.97 (m, 1H), 2.11 (s, 3H), 2.24 (s, 3H), 2.42 (d, J = 13.6Hz, 1H), 2.64 (d, J = 13.9Hz, 1H), 3.30-3.43 (m, 4H), 3.65 (s, 3H), 3.67 (s, 3H) ), 4.93-5.05 (m, 4H), 5.89-6.00 (m, 2H), 6.83 (s, 1H), 6.85 (s, 1), 6.95 (s, 1H), 6.96 (s, 1H).

[0049] <Evaluation of Heat Resistance> In order to compare the heat resistance of the obtained compound (1-2) of the present invention with that of commonly used curing agents, the 5% weight loss temperature of each compound was measured. The curing agents used in the comparative examples are compounds represented by chemical formulas (x-1) to (x-3) (referred to as "compound (x-1)," "compound (x-2)," and "compound (x-3)," respectively). Compound (x-1) and compound (x-2) are known substances and were synthesized by the inventor. Compound (x-3) manufactured by Tokyo Chemical Industry Co., Ltd. was used. The measurement results are shown in Table 1 below.

[0050] As shown in Table 1, it was revealed that the allyl group-containing alkoxy compound of the present invention having a cyclohexyl group has higher heat resistance than compound (x-3) (triallyl isocyanurate). When heated at high temperatures of about 200°C to cure the thermosetting resin used in forming the prepreg, compound (x-3) lost weight by 5% or more, confirming that problems due to volatilization of components could occur. On the other hand, it was also revealed that the compound of the present invention has high heat resistance when heated at high temperatures of about 200°C to cure, and therefore can be expected to contribute to reducing problems due to volatilization of components.

[0051] Example 2: 100 parts by weight of a (meth)acrylate-terminated copolymer of 2,6-dimethylphenol and 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 100 parts by weight of toluene, 3.1 parts by weight of compound (1-2) as a curing agent, and 0.68 parts by weight of dicumyl peroxide (manufactured by NOF Corporation: trade name "Percumyl D") were blended and stirred at room temperature with a magnetic stirrer to prepare a varnish. The varnish was applied to a 20 cm square polyimide film (manufactured by Ube Industries, Ltd.: trade name "Upilex") to a thickness of 0.2 mm. The mixture was then dried at room temperature and the solvent was removed using a vacuum dryer at 105°C for 1 hour to obtain a semi-cured prepreg.

[0052] [Resin Film Preparation] A mold made of aluminum foil (0.12 mm thick) with a 6 cm x 6 cm hole was sandwiched between the prepreg on both sides, then sandwiched between two other polyimide films on both sides, and then sandwiched between 25 cm x 25 cm metal plates on both sides. The mixture was then pressed and cured using a heat press (manufactured by Toyo Seiki Co., Ltd.) under the following temperature, pressure, and time conditions: heating temperature 105°C, pressure 10 MPa, 30 minutes → heating temperature 150°C, pressure 10 MPa, 1 hour → heating temperature 200°C, pressure 10 MPa, 1 hour → heating temperature 250°C, pressure 10 MPa, 1 hour → heating temperature 270°C, pressure 10 MPa, 1 hour). The polyimide film adhering to the cured product was removed to obtain a resin film. The resulting resin film was evaluated for dielectric properties using the method described above. The results are shown in Table 2.

[0053] Example 3 and Comparative Examples 1 to 7 Prepregs and resin films were prepared in the same manner as in Example 2 above, except that the compound (1-2) used as the curing agent and its amount used were the compound and amount used shown in Table 2, and dielectric property evaluations were carried out. In Comparative Examples 1 to 7, in addition to the compounds (x-1) and (x-2) above, the following compound (x-4) was used as the curing agent. The compounds, their amounts used, and the results of the dielectric property evaluations are summarized in Table 2.

[0054]

[0055]

[0056] As shown in Table 2, when compound (1-2) was used in a small amount, the dielectric loss tangent decreased compared to when compounds (x-1), (x-2), and (x-4) were used, and the dielectric constant calculated from the dielectric constant and the dielectric loss tangent (dielectric constant) ０．５ It was also revealed that the value of × (dielectric loss tangent) was low. It was also revealed that the relative dielectric constant and dielectric loss tangent were lower than those of Comparative Example 7, which did not use a curing agent, and that the dielectric properties were improved.

[0057] That is, since the allyl group-containing alkoxy compound of the present invention has low volatility, when it is used as a curing agent for curing a polyphenylene ether resin, problems such as equipment contamination due to volatilization of the curing agent can be reduced, which is very beneficial in terms of yield and production efficiency. Furthermore, when the allyl group-containing alkoxy compound of the present invention is used as a curing agent for curing a polyphenylene ether resin, the obtained resin has improved dielectric properties, making it industrially very useful.

Claims

1. An allyl group-containing alkoxy compound represented by general formula (1): (In the formula, R １ each independently represents a linear alkyl group having 1 to 6 carbon atoms or a branched alkyl group having 3 to 6 carbon atoms; X represents a cycloalkylidene group having 5 to 20 carbon atoms; each n independently represents 0 or an integer of 1 to 3; and each m independently represents an integer of 1 to 6.

2. The allyl group-containing alkoxy compound according to claim 1, wherein X is 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), or a cyclododecanylidene group (12 carbon atoms).

3. The allyl group-containing alkoxy compound according to claim 1, which is any one of the compounds represented by chemical formulas (1-1) to (1-6).

4. A polyphenylene ether resin curing agent comprising the allyl group-containing alkoxy compound according to claim 1.

5. A method of curing a polyphenylene ether resin with a curing agent containing an allyl group-containing alkoxy compound represented by general formula (1). (In the formula, R １ each independently represents a linear alkyl group having 1 to 6 carbon atoms or a branched alkyl group having 3 to 6 carbon atoms; X represents a cycloalkylidene group having 5 to 20 carbon atoms; each n independently represents 0 or an integer of 1 to 3; and each m independently represents an integer of 1 to 6.

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