JP6402448B2 - Cyanate ester compound, curable resin composition containing the compound, and cured product thereof - Google Patents

Description

The present invention relates to a novel cyanate ester compound, a curable resin composition containing the compound, and a cured product thereof.

Cyanate ester compounds produce triazine rings upon curing, and due to their high heat resistance and excellent electrical properties, various functional polymer materials such as structural composite materials, adhesives, electrical insulating materials, and electrical and electronic parts are used. Widely used as a raw material. However, in recent years, with the sophistication of required performance in these application fields, various physical properties required as a functional polymer material have become increasingly severe. Examples of such physical properties include flame retardancy, heat resistance, low thermal expansion coefficient, low water absorption, low dielectric constant, low dielectric loss tangent, weather resistance, chemical resistance, and high fracture toughness. However, so far, these required physical properties have not always been satisfied.

Epoxy resins are generally used for curable resin compositions for sealing semiconductor elements, and include epoxy resins such as bisphenol A type epoxy resins as main components, and liquid acid anhydrides and phenol novolacs as curing agents. An epoxy resin composition containing an additive such as an inorganic filler has been proposed (see, for example, Patent Documents 1 to 3).

In the semiconductor encapsulating material field, with the aim of reducing power loss, studies for replacing semiconductor elements from silicon (Si) to wide gap semiconductors such as silicon carbide (SiC) are being actively conducted. Further, replacement with SiC semiconductor or the like can be expected not only to reduce power loss but also to reduce the size of the semiconductor device by simplifying the cooling device. This is because the SiC semiconductor is chemically more stable than the Si semiconductor, and thus can operate at a high temperature exceeding 200 ° C. However, a resin composition mainly composed of an epoxy resin or the like has a low glass transition temperature and cannot be said to have sufficient heat resistance at temperatures exceeding 200 ° C.

On the other hand, as a resin composition having a heat resistance exceeding 200 ° C. using a cyanate ester compound, for example, in Patent Document 4, a cyanate ester compound having a specific structure, a phenol compound having a specific structure, and an inorganic filler And a resin composition having an organometallic compound content of 100 ppm or less has been proposed. However, the long-term heat resistance test in Patent Document 4 is about 50 hours (250 ° C.), which is not sufficient as the test time. Further, no mention is made of viscosity and moisture absorption resistance.

JP 2003-160639 A JP 2009-292996 A JP 2008-255367 A JP2013-53218A

An object of the present invention is to provide a novel cyanate ester compound, a curable resin composition containing the compound, and the like from which a cured product having low viscosity and excellent heat resistance and moisture absorption resistance can be obtained. is there.

The present inventors have found that a cyanate ester compound obtained by cyanating a hydroxyl group-containing aromatic compound obtained by polycondensation of a hydroxy-substituted aromatic compound, an aromatic aldehyde compound and an aralkyl compound with cyanogen halide has a low melt viscosity. It is found that the curable resin composition using the cyanate ester compound can realize a cured product having excellent flame retardancy, heat resistance, and moisture absorption resistance. The invention has been reached. That is, the present invention is as follows.

1. A cyanate ester compound represented by the following general formula (1).
(In the formula, Ar ¹ represents an aryl group, R ¹ represents a monovalent substituent, each independently represents a hydrogen atom, an alkyl group or an aryl group. Ar ² each independently represents a phenylene group, a naphthylene group, or .Ar ³ each independently phenylene group representing a biphenylene group, .R ² representing a naphthylene group or a biphenylene group denotes a monovalent substituent, each independently represent a hydrogen atom, an alkyl group, an aryl group, or cyanato group. n represents the number of bonds of the cyanate group and is an integer of 1 to 3. m represents the number of bonds of R ^{1 obtained} by subtracting n from the number of bonds that Ar ¹ has, and p represents the number of bonds of R ^{2 to} Ar ³ . Represents an integer of 1 to 5. x is an integer of 1 to 40. y is an integer of 1 to 20. Even if each repeating unit of x and y is continuously arranged, It may be arranged alternately or randomly )

2. Ar ¹ , Ar ² and Ar ³ are each independently a phenylene group or a biphenylene group; The cyanate ester compound described in 1.

3. Ar ¹ , Ar ² and Ar ³ are phenylene groups; The cyanate ester compound described in 1.

4). Ar ¹ and Ar ³ are phenylene groups and Ar ² is a biphenylene group. The cyanate ester compound described in 1.

5. A cyanate ester compound obtained by cyanating a hydroxyl group-containing aromatic compound obtained by polycondensation of a hydroxy-substituted aromatic compound, an aromatic aldehyde compound and an aralkyl compound represented by the following general formula (2) with cyanogen halide .
(In the formula, each Ar ⁴ independently represents a phenylene group, a naphthylene group or a biphenylene group, and X represents an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group or a halogen atom.)

6). 1. ~ 5. A curable resin composition comprising the cyanate ester compound according to any one of the above.

7). Furthermore, ~ 5. 5. At least one selected from the group consisting of a cyanate ester compound other than the cyanate ester compound according to any one of the above, an epoxy resin, an oxetane resin, and a compound having a polymerizable unsaturated group. The curable resin composition described in 1.

8). Furthermore, an inorganic filler is included. Or 7. The curable resin composition described in 1.

9. 6). ~ 8. Hardened | cured material formed by hardening | curing curable resin composition as described in any one of these.

10. 6). ~ 8. The sealing material containing the curable resin composition as described in any one of these.

11. 6). ~ 8. A prepreg for a structural material, wherein the curable resin composition according to any one of the above is impregnated or coated on a base material and dried.

12 6). ~ 8. A fiber-reinforced composite material comprising the curable resin composition according to any one of the above.

13. 6). ~ 8. The adhesive agent containing the curable resin composition as described in any one of these.

According to the present invention, a curable resin composition or a cured product having excellent heat resistance and moisture absorption resistance can be realized by using a novel cyanate ester compound.

2 is a FT-IR chart of the cyanate ester compound obtained in Example 1. FIG. 2 is a FT-IR chart of the cyanate ester compound obtained in Example 2. FIG. 4 is an FT-IR chart of the cyanate ester compound obtained in Synthesis Example 3. FIG.

The present invention is a cyanate ester compound represented by the general formula (1) and a curable resin composition comprising the cyanate ester compound.

In another aspect of the present invention, a cured product obtained by curing the curable resin composition, a sealing material comprising the curable resin composition, a fiber-reinforced composite material, an adhesive, and a metal-clad A laminate is also provided.

Although the method of obtaining the cyanate ester compound represented by General formula (1) is not specifically limited, For example, it obtains by cyanating the hydroxyl group of the hydroxyl-containing aromatic compound which has a structure represented by General formula (3). Can do.

^{(Wherein, Ar 1, Ar 2, Ar} 3, R 1, R 2, m, p, x, y of the general formula (1) and Ri synonymous der, n 'represents a bond number of hydroxyl groups.)

The method for obtaining the hydroxyl group-containing aromatic compound having the structure represented by the general formula (3) is not particularly limited, and examples thereof include hydroxy-substituted aromatic compounds , aromatic aldehydes, and aralkyl represented by the general formula (2). It can be obtained by reacting the compound in the presence of an acid catalyst. The method will be described in detail below.

< Hydroxy-substituted aromatic compound >
The hydroxy-substituted aromatic compound is not particularly limited as long as it is a compound containing an aromatic ring and a hydroxyl group. For example, phenol, o-cresol, m-cresol, p-cresol, 2,6-xylenol, 2-phenylphenol , 4-phenylphenol, 1-naphthol, 2-naphthol, resorcinol, dihydroxybiphenyl, tetramethyldihydroxybiphenyl, bisphenol A, bisphenol S, bisphenol F, etc., among which the heat resistant viewpoint of the cyanate ester compound obtained Therefore, phenol, 1-naphthol, and bisphenol A are preferable.

<Aromatic aldehyde>
The aromatic aldehyde is not particularly limited as long as it is a compound containing an aromatic ring and a formyl group. For example, benzaldehyde, 2-methylbenzaldehyde, 4-methylbenzaldehyde, 2-phenylbenzaldehyde, 4-phenylbenzaldehyde, 2,4 -Dimethylbenzaldehyde, 2,4,6-trimethylbenzaldehyde, salicylaldehyde, 4-hydroxybenzaldehyde, and the like. Among them, benzaldehyde, 4-methylbenzaldehyde, 4-phenyl are used from the viewpoint of heat resistance of the obtained cyanate ester compound. Benzaldehyde, salicylaldehyde, and 4-hydroxybenzaldehyde are preferable.

<Aralkyl compounds>
The aralkyl compound represented by the general formula (2) is not particularly limited as long as it is a compound having an aralkyl structure. For example, o-, m- or p-xylylene glycol, 4,4′-bishydroxymethylbiphenyl. 2,4′-bishydroxymethylbiphenyl, o-, m- or p-xylylene glycol dimethyl ether, 4,4′-bismethoxymethylbiphenyl, 2,4′-bismethoxymethylbiphenyl, o-, m- or p-xylylene glycol diethyl ether, 4,4′-bisethoxymethylbiphenyl, 2,4′-bisethoxymethylbiphenyl, o-, m- or p-xylylene glycol diacetyl ester, 4,4′-bisacetoxymethyl Biphenyl, 2,4′-bisacetoxymethylbiphenyl, α, α′-dichloro-o-xy Len, α, α'-dichloro-m-xylene, α, α'-dichloro-p-xylene, 4,4'-bis (chloromethyl) biphenyl, 2,4'-bis (chloromethyl) biphenyl, 2, 2'-bis (chloromethyl) biphenyl and the like. Among them, p-xylylene glycol, 4,4'-bishydroxymethylbiphenyl, p-xylylene from the viewpoint of moisture absorption resistance of the resulting cyanate ester compound Glycol dimethyl ether, 4,4′-bismethoxymethylbiphenyl, p-xylylene glycol diethyl ether, 4,4′-bisethoxymethylbiphenyl, α, α′-dichloro-p-xylene, 4,4′-bis (chloro Methyl) biphenyl is preferred.

Acid catalysts used for the production of hydroxyl-containing aromatic compounds obtained by polycondensation of hydroxy-substituted aromatic compounds , aromatic aldehyde compounds and aralkyl compounds include inorganic acids such as phosphoric acid, sulfuric acid, hydrochloric acid, oxalic acid, and benzene Any of organic acids such as sulfonic acid, toluenesulfonic acid and methanesulfonic acid may be used.

The reaction temperature in the reaction is 80 to 300 ° C, preferably 100 to 180 ° C. Although reaction time is not specifically limited, It is preferable that it is the range which can maintain the said temperature conditions for 1 to 10 hours. Since this reaction proceeds while forming alcohol or carboxylic acid depending on the type of aralkyl compound in addition to water generated by condensation, it is desirable to dealcoholate or decarboxylate with dehydration or dehydration under normal pressure or reduced pressure. . However, in the initial stage of the reaction, the reaction can also proceed under reflux.

For hydroxy-substituted aromatic compound, the total proportion of the aromatic aldehyde compound and the aralkyl compound per mole hydroxy-substituted aromatic compound is 0.4 to 0.95 mol. If it is in the said range, the melt viscosity of the cyanate ester compound obtained will be low, and heat resistance will also become favorable.

Moreover, the ratio of the aralkyl compound with respect to an aromatic aldehyde compound is the range of 0.1-1.3 mol with respect to 1 mol of aromatic aldehyde compounds, Preferably it is 0.2-1.2 mol. If it is in the said range, the hygroscopic property of the hardened | cured material obtained will be low, and heat resistance will also become favorable.

<Cyanate ester compound>
The cyanate ester compound of the present invention can be obtained by cyanating a hydroxy group of a hydroxyl group-containing aromatic compound obtained by polycondensation of the above hydroxy-substituted aromatic compound , aromatic aldehyde compound and aralkyl compound. The cyanating method is not particularly limited, and a known method can be applied. Specifically, a method of reacting a hydroxyl group-containing aromatic compound obtained by polycondensation of a hydroxy-substituted aromatic compound, an aromatic aldehyde compound and an aralkyl compound with cyanogen halide in a solvent in the presence of a basic compound, In a solvent, in the presence of a base, cyanogen halide is always present in excess of the base so that the phenol resin reacts with cyanogen halide (US Pat. No. 3,553,244), or a tertiary amine is used as the base. After adding a tertiary amine in the presence of a solvent to a hydroxyl group-containing aromatic compound obtained by polycondensation of a hydroxy-substituted aromatic compound, an aromatic aldehyde compound and an aralkyl compound while using this in excess of cyanogen halide , A method of dropping cyan halide or a method of dropping together cyan halide and tertiary amine (patented) 319061), a method of reacting phenol resin, trialkylamine and cyanogen halide in a continuous plug flow method (Japanese Patent No. 3905559), phenol resin and cyanogen halide in the presence of tert-amine, A method of treating a tert-ammonium halide by-produced in a reaction in an aqueous solution with a cation and anion exchange pair (Japanese Patent No. 40552210), a tertiary resin in the presence of a solvent that can be separated from water. A method in which an amine and a cyanogen halide are added and reacted at the same time, then washed with water, and subjected to precipitation purification using a secondary or tertiary alcohol or a poor hydrocarbon solvent from the resulting solution (Japanese Patent No. 291054) ), And naphthols, cyanogen halides, and tertiary amines in two phases of water and an organic solvent. In a solvent, method of reacting under acidic conditions is known (Patent 5026727 JP), etc., in the present invention, by using these methods suitably, it is possible to obtain a cyanate ester compound.

The above-described method was used in which a hydroxyl group-containing aromatic compound obtained by polycondensation of a hydroxy-substituted aromatic compound, an aromatic aldehyde compound and an aralkyl compound and cyanogen halide are reacted in a solvent in the presence of a basic compound. In this case, a hydroxyl group-containing aromatic compound obtained by polycondensation of a reaction substrate, a hydroxy-substituted aromatic compound, an aromatic aldehyde compound and an aralkyl compound, was previously dissolved in either a cyanogen halide solution or a basic compound solution. Thereafter, the cyanogen halide solution and the basic compound solution are brought into contact with each other.
The cyan halide solution and the basic compound solution are brought into contact with each other as follows: (A) a method in which the basic compound solution is poured into the stirred cyan halide solution, and (B) a basic mixture that is stirred and mixed. Examples include a method in which a cyan halide solution is poured into a compound solution, and a method (C) in which a cyan halide solution and a basic compound solution are continuously or alternately supplied.
Among the methods (A) to (C), side reactions are suppressed and a higher purity cyanate ester compound can be obtained in a high yield. Therefore, the method (A) is preferable.
Moreover, the contact method of the said cyanogen halide solution and a basic compound solution can be performed either in a semi-batch format or a continuous flow format.
In particular, when the method (A) is used, the reaction can be completed without leaving the hydroxyl group of the hydroxyl group-containing aromatic compound obtained by polycondensation of the hydroxy-substituted aromatic compound , aromatic aldehyde compound and aralkyl compound. In addition, since a higher purity cyanate ester compound can be obtained in a high yield, it is preferable to divide and drop the basic compound. The number of divisions is not particularly limited, but is preferably 1 to 5 times. In addition, the type of basic compound may be the same or different for each division.

Examples of the cyanogen halide used in the present invention include cyanogen chloride and cyanogen bromide. As the cyanide halide, a cyanide halide obtained by a known production method such as a method of reacting hydrogen cyanide or metal cyanide with halogen may be used, or a commercially available product may be used. In addition, a reaction liquid containing cyanogen halide obtained by reacting hydrogen cyanide or metal cyanide with halogen can be used as it is.

The amount used for the hydroxy-containing aromatic compound obtained by polycondensation of the cyanogen halide hydroxy-substituted aromatic compound , aromatic aldehyde compound and aralkyl compound in the cyanation step of the present invention is hydroxy-substituted aromatic compound , aromatic aldehyde. It is 0.5-5 mol with respect to 1 mol of hydroxyl groups of the hydroxyl-containing aromatic compound obtained by polycondensing a compound and an aralkyl compound, Preferably it is 1.0-3.5.
The reason is that the yield of the cyanate ester compound can be increased without leaving the hydroxyl group-containing aromatic compound obtained by polycondensation of the unreacted hydroxy-substituted aromatic compound , aromatic aldehyde compound and aralkyl compound. .

Solvents used for the cyanogen halide solution include ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, aliphatic solvents such as n-hexane, cyclohexane, isooctane, cyclohexanone, cyclopentanone, and 2-butanone, benzene, and toluene. , Aromatic solvents such as xylene, diethyl ether, dimethyl cellosolve, diglyme, tetrahydrofuran, methyltetrahydrofuran, dioxane, tetraethylene glycol dimethyl ether and other ether solvents, dichloromethane, chloroform, carbon tetrachloride, dichloroethane, trichloroethane, chlorobenzene, bromo Halogenated hydrocarbon solvents such as benzene, methanol, ethanol, isopropanol, methylsolvosolve, propylene glycol mono Alcohol solvents such as tilether, aprotic polar solvents such as N, N-dimethylformamide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidone and dimethyl sulfoxide, nitrile solvents such as acetonitrile and benzonitrile, nitromethane Nitro solvents such as nitrobenzene, ester solvents such as ethyl acetate and ethyl benzoate, hydrocarbon solvents such as cyclohexane, water solvents and the like can be used. Can be used in combination.

As the basic compound used in the cyanate formation step of the present invention, either an organic or inorganic base can be used.

Examples of organic bases include trimethylamine, triethylamine, tri-n-butylamine, triamylamine, diisopropylethylamine, diethyl-n-butylamine, methyldi-n-butylamine, methylethyl-n-butylamine, dodecyldimethylamine, tribenzylamine, Triethanolamine, N, N-dimethylaniline, N, N-diethylaniline, diphenylmethylamine, pyridine, diethylcyclohexylamine, tricyclohexylamine, 1,4-diazabicyclo [2.2.2] octane, 1,8- Tertiary amines such as diazabicyclo [5.4.0] -7-undecene and 1,5-diazabicyclo [4.3.0] -5-nonene are preferred. Among these, trimethylamine, triethylamine, tri-n-butylamine, and diisopropylethylamine are more preferable, and triethylamine is particularly preferable because the target product can be obtained with high yield.

The amount of the organic base used is usually 0.1 to 8 mol, preferably 1 to 8 mol, based on 1 mol of the hydroxyl group of the hydroxyl group-containing aromatic compound obtained by polycondensation of a hydroxy-substituted aromatic compound, an aromatic aldehyde compound and an aralkyl compound. Is 1.0 to 3.5 moles.
The reason is to increase the yield of the cyanate ester compound without leaving the hydroxyl group-containing aromatic compound obtained by polycondensation of the unreacted hydroxy-substituted aromatic compound , aromatic aldehyde compound and aralkyl compound.

As the inorganic base, an alkali metal hydroxide is preferable. Examples of the alkali metal hydroxide include, but are not limited to, sodium hydroxide, potassium hydroxide, and lithium hydroxide that are generally used industrially. Sodium hydroxide is particularly preferable because it can be obtained at low cost.

The amount of the inorganic base used is usually 1.0 to 5.0 moles with respect to 1 mole of a hydroxyl group of a hydroxyl group-containing aromatic compound obtained by polycondensation of a hydroxy-substituted aromatic compound, an aromatic aldehyde compound and an aralkyl compound. , Preferably 1.0 to 3.5 mol.
The reason is to increase the yield of the cyanate ester compound without leaving the hydroxyl group-containing aromatic compound obtained by polycondensation of the unreacted hydroxy-substituted aromatic compound , aromatic aldehyde compound and aralkyl compound.

In the reaction of the present invention, the basic compound can be used as a solution dissolved in a solvent as described above. As the solvent, an organic solvent or water can be used.

The amount of the solvent used in the basic compound solution is such that when the hydroxyl group-containing aromatic compound obtained by polycondensation of the hydroxy-substituted aromatic compound , aromatic aldehyde compound and aralkyl compound is dissolved in the basic compound solution, the hydroxy-substituted aromatic compound is used. It is 0.1-100 mass parts normally with respect to 1 mass part of hydroxyl-containing aromatic compounds obtained by polycondensing an aromatic compound, an aromatic aldehyde compound, and an aralkyl compound, Preferably it is 0.5-50 mass parts.
When a hydroxyl group-containing aromatic compound obtained by polycondensation of a hydroxy-substituted aromatic compound, an aromatic aldehyde compound and an aralkyl compound is not dissolved in the basic compound solution, it is usually 0.1 to 1 part by mass of the basic compound. 100 parts by mass, preferably 0.25 to 50 parts by mass.

The organic solvent for dissolving the basic compound is preferably used when the basic compound is an organic base, for example, a ketone solvent such as acetone, methyl ethyl ketone, or methyl isobutyl ketone, an aromatic solvent such as benzene, toluene, xylene, Ether solvents such as diethyl ether, dimethyl cellosolve, diglyme, tetrahydrofuran, methyltetrahydrofuran, dioxane, tetraethylene glycol dimethyl ether, halogenated hydrocarbon solvents such as dichloromethane, chloroform, carbon tetrachloride, dichloroethane, trichloroethane, chlorobenzene and bromobenzene Alcohol solvents such as methanol, ethanol, isopropanol, methylsolvosolve, propylene glycol monomethyl ether, N, N-dimethylforma , Aprotic polar solvents such as N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidone and dimethyl sulfoxide, nitrile solvents such as acetonitrile and benzonitrile, nitro solvents such as nitromethane and nitrobenzene, ethyl acetate, benzoic acid An ester solvent such as ethyl acid and a hydrocarbon solvent such as cyclohexane can be appropriately selected according to the basic compound, the reaction gas, and the solvent used in the reaction. These can be used alone or in combination of two or more.

The water for dissolving the basic compound is preferably used when the basic compound is an inorganic base, and is not particularly limited, and may be tap water, distilled water, or deionized water. . In order to efficiently obtain the target cyanate ester compound, it is preferable to use distilled water or deionized water with less impurities.

When the solvent used for the basic compound solution is water, it is preferable to use a catalytic amount of an organic base as a surfactant from the viewpoint of securing the reaction rate. Of these, tertiary amines with few side reactions are preferred. The tertiary amine may be any of alkylamine, arylamine, and cycloalkylamine. Specifically, trimethylamine, triethylamine, tri-n-butylamine, triamylamine, diisopropylethylamine, diethyl-n-butylamine, methyldi-n- Butylamine, methylethyl-n-butylamine, dodecyldimethylamine, tribenzylamine, triethanolamine, N, N-dimethylaniline, N, N-diethylaniline, diphenylmethylamine, pyridine, diethylcyclohexylamine, tricyclohexylamine, 1 , 4-diazabicyclo [2.2.2] octane, 1,8-diazabicyclo [5.4.0] -7-undecene, 1,5-diazabicyclo [4.3.0] -5-nonene. . Among these, trimethylamine, triethylamine, tri-n-butylamine, and diisopropylethylamine are more preferable, and triethylamine is particularly preferable because the target product can be obtained with high solubility and yield in water.

The total amount of the solvent used in the cyanation step of the present invention is 2.5 to 1 part by mass with respect to 1 part by mass of a hydroxyl group-containing aromatic compound obtained by polycondensation of a hydroxy-substituted aromatic compound, an aromatic aldehyde compound and an aralkyl compound. It is preferable from the viewpoint of efficiently producing a cyanate ester compound by uniformly dissolving a hydroxyl group-containing aromatic compound obtained by polycondensation of a hydroxy-substituted aromatic compound, an aromatic aldehyde compound and an aralkyl compound.

In the cyanating step of the present invention, the pH of the reaction solution is not particularly limited, but it is preferable to carry out the reaction while maintaining the pH below 7. This is because by suppressing the pH to less than 7, the production of by-products such as a polymer of imide carbonate and cyanate ester compound is suppressed, and the cyanate ester compound can be produced efficiently. In order to keep the pH of the reaction solution below 7, it is preferable to add an acid. As the method, an acid is added to the cyanogen halide solution immediately before the cyanation step, and a pH meter is used as needed during the reaction. However, it is preferable to add an acid to the reaction system so as to keep the pH below 7.
Examples of the acid used at that time include inorganic acids such as hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid, and organic acids such as acetic acid, lactic acid, and propionic acid.

The reaction temperature in the cyanation step of the present invention is such that byproducts such as imide carbonate, a polymer of cyanate ester compound, and dialkylcyanoamide, condensation of the reaction solution, and cyanide chloride as cyanide halide are used. From the viewpoint of suppressing the volatilization of cyanogen chloride, it is usually -20 to + 50 ° C, preferably -15 to 15 ° C, more preferably -10 to 10 ° C.

The reaction pressure in the cyanation step of the present invention may be normal pressure or increased pressure. If necessary, an inert gas such as nitrogen, helium, or argon may be passed through the system.
Moreover, although reaction time is not specifically limited, 1 minute-20 hours are preferable as dropping time in the case of the said contact method being (A) and (B), and contact time in the case of (C), 3 minutes-10 hours Is more preferable. Furthermore, it is preferable to stir while maintaining the reaction temperature for 10 minutes to 10 hours thereafter.
By setting it as such a range, the target cyanate ester compound can be obtained economically and industrially.

The degree of progress of the reaction in the cyanation step can be analyzed by liquid chromatography or IR spectrum method. Volatile components such as by-product dicyan and dialkylcyanoamide can be analyzed by gas chromatography.

After completion of the reaction, the intended cyanate ester compound can be isolated by carrying out ordinary post-treatment operations and, if desired, separation / purification operations. Specifically, an organic solvent layer containing a cyanate ester compound is separated from the reaction solution, washed with water, concentrated, precipitated or crystallized, or washed with water and then replaced with a solvent. At the time of washing, in order to remove excess amines, a method using an acidic aqueous solution such as dilute hydrochloric acid is also employed. In order to remove water from the sufficiently washed reaction solution, a drying operation can be performed by a general method using sodium sulfate, magnesium sulfate or the like. At the time of concentration and solvent replacement, in order to suppress polymerization of the cyanate ester compound, the organic solvent is distilled off by heating to a temperature of 90 ° C. or lower under reduced pressure. In precipitation or crystallization, a solvent having low solubility can be used. For example, an ether solvent, a hydrocarbon solvent such as hexane, or an alcohol solvent may be dropped into the reaction solution, or a reverse pouring method may be employed. In order to wash the obtained crude product, a method of washing the concentrate of the reaction solution and the precipitated crystals with an ether solvent, a hydrocarbon solvent such as hexane, or an alcohol solvent can be employed. The crystals obtained by concentrating the reaction solution can be dissolved again and then recrystallized. In the case of crystallization, the reaction solution may be simply concentrated or cooled.

The specific structure of the cyanate ester compound represented by the general formula (1) of the present invention is, for example, when phenol is used as the hydroxy-substituted aromatic compound, alkylbenzaldehyde is used as the aromatic aldehyde compound, and paraxylene glycol dimethyl ether is used as the aralkyl compound. In the case of using phenol as the hydroxy-substituted aromatic compound, alkylbenzaldehyde as the aromatic aldehyde compound, and 4,4′-bis (chloromethyl) biphenyl as the aralkyl compound. Has a structure represented by the following (5). The values of m and n vary depending on the reaction conditions such as the amount ratio of hydroxy-substituted aromatic compound , aromatic aldehyde and aralkyl compound used in the polycondensation, the amount of acid, and the reaction temperature. m and n are an integer of 1-20, and an integer of 1-10 is more preferable. If it is in the said range, the hygroscopic property of the hardened | cured material obtained will be low, and heat resistance will also become favorable.

(In the formula, m and n are integers of 1 to 20. Each repeating unit of m and n may be continuously arranged, or may be alternately or randomly arranged. R ² is a hydrogen atom. An alkyl group, an aryl group, and a cyanato group, p represents the number of R ² bonds to the phenyl group, and is an integer of 1 to 5.)

(In the formula, m, n, R ² and p are as defined above.)

The number average molecular weight Mn of the cyanate ester compound of the present invention is not particularly limited, but is preferably 200 to 5000, and more preferably 300 to 2000.

The obtained cyanate ester compound can be identified by a known method such as NMR. The purity of the cyanate ester compound can be analyzed by liquid chromatography or IR spectroscopy. Byproducts such as dialkylcyanoamide in the cyanate ester compound and volatile components such as residual solvent can be quantitatively analyzed by gas chromatography. Halogen compounds remaining in the cyanate ester compound can be identified by a liquid chromatograph mass spectrometer, and can be quantitatively analyzed by potentiometric titration using a silver nitrate solution or ion chromatography after decomposition by a combustion method. . The polymerization reactivity of the cyanate ester compound can be evaluated by gelation time by a hot plate method or a torque measurement method.

<Curable resin composition>
The curable resin composition of this invention contains the cyanate ester compound mentioned above. This curable resin composition has a cyanate ester compound other than the above-described cyanate ester compound (hereinafter referred to as “other cyanate ester compound”), an epoxy resin, and an oxetane as long as desired characteristics are not impaired. It may contain a resin, a benzoxazine compound, and / or a compound having a polymerizable unsaturated group.

The other cyanate compound is a compound having an aromatic moiety substituted with at least one cyanate group in the molecule, and is not particularly limited as long as it is other than the cyanate ester compound represented by the general formula (1). Not. For example, what is represented by General formula (6) is mentioned.
(In the formula, Ar ⁵ represents a phenylene group, a naphthylene group or a biphenylene group. R ³ each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkyl group having 1 to 4 carbon atoms. Or an alkyl group having 1 to 6 carbon atoms and an aryl group having 6 to 12 carbon atoms, wherein the substituent of the aromatic ring can be selected at any position, and q is the number of bonds of the cyanate group. And is an integer of 1 to ^3. r represents the number of R ³ bonds, 4-q when Ar ⁵ is a phenylene group, 6-q when a naphthylene group, and 8-q when a biphenylene group. T represents an integer of 0 to 50, but may be a mixture of compounds having different t. Y is a single bond, a divalent organic group having 1 to 20 carbon atoms (a hydrogen atom is replaced by a hetero atom) A divalent organic group having 1 to 10 nitrogen atoms (—N—R—N— ), Carbonyl group (—CO—), carboxy group (—C (═O) O—), carbonyl dioxide group (—OC (═O) O—), sulfonyl group (—SO 2 —), divalent sulfur Represents either an atom or an oxygen atom.)

The alkyl group in R ³ of the general formula (6) may have either a chain structure or a cyclic structure (cycloalkyl group or the like).
Further, the hydrogen atom in the alkyl group in the general formula (6) and the aryl group in R ³ may be substituted with a halogen atom such as fluorine or chlorine, an alkoxy group such as a methoxy group or a phenoxy group, a cyano group, or the like. .
Specific examples of the alkyl group include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, 1-ethylpropyl, 2,2-dimethyl. A propyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, a trifluoromethyl group and the like can be mentioned.
Specific examples of the aryl group include phenyl, xylyl, mesityl, naphthyl, phenoxyphenyl, ethylphenyl, o-, m- or p-fluorophenyl, dichlorophenyl, dicyanophenyl, trifluoro. A phenyl group, a methoxyphenyl group, o-, m- or p-tolyl group and the like can be mentioned. Furthermore, examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, and a tert-butoxy group.
Specific examples of the divalent organic group in Y of the general formula (6) include a methylene group, an ethylene group, a trimethylene group, a propylene group, a cyclopentylene group, a cyclohexylene group, a trimethylcyclohexylene group, a biphenylylmethylene group, Examples thereof include a dimethylmethylene-phenylene-dimethylmethylene group, a fluorenediyl group, and a phthalidodiyl group. The hydrogen atom in the divalent organic group may be substituted with a halogen atom such as fluorine or chlorine, an alkoxy group such as a methoxy group or a phenoxy group, a cyano group, or the like.
Examples of the divalent organic group having 1 to 10 nitrogen atoms in Y of the general formula (6) include an imino group and a polyimide group.

Moreover, as Y in General formula (6), what is a structure represented by following General formula (7), following General formula (8), or a following formula is mentioned.
(In the formula, Ar ⁶ represents a phenylene group, a naphthylene group or a biphenylene group. R ⁴ , R ⁵ , R ⁸ and R ⁹ each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or 6 to 12 carbon atoms. R ⁶ and R ⁷ each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or 6 carbon atoms. Represents an aryl group of -12, an alkoxy group of 1 to 4 carbon atoms, or a cyanato group, u represents an integer of 0 to 5, but may be the same or different.

(Wherein, Z is a methylene group, a methyleneoxy group, a methyleneoxy methylene group or oxymethylene group, a divalent sulfur atom, or .R ¹⁰ is hydrogen atom represents an oxygen atom, an alkyl group having 1 to 6 carbon atoms, a carbon Represents an aryl group substituted with at least one aryl group, trifluoromethyl group, or cyanato group of formulas 6 to 12. v represents an integer of 0 to 50, but v may be a mixture of different compounds. W represents an integer of 0 to 4.)

(In the formula, z represents an integer of 4 to 7. Each R ¹⁰ independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.)
Specific examples of Ar ^{6 in} the general formula (7) include 1,4-phenylene group, 1,3-phenylene group, 4,4′-biphenylene group, 2,4′-biphenylene group, and 2,2′-biphenylene. Group, 2,3′-biphenylene group, 3,3′-biphenylene group, 3,4′-biphenylene group, 2,6-naphthylene group, 1,5-naphthylene group, 1,6-naphthylene group, 1,8 -A naphthylene group, a 1, 3- naphthylene group, a 1, 4- naphthylene group etc. are mentioned.
The alkyl group and aryl group in R ^{4 to} R ⁹ in the general formula (7) have the same meanings as those described in the general formula (6).

Specific examples of the cyanato-substituted aromatic compound represented by the general formula (8) include cyanatobenzene, 1-cyanato-2-, 1-cyanato-3-, or 1-cyanato-4-methylbenzene, 1- Cyanato-2-, 1-cyanato-3-, or 1-cyanato-4-methoxybenzene, 1-cyanato-2,3-, 1-cyanato-2,4-, 1-cyanato-2,5-, 1 -Cyanato-2,6-, 1-cyanato-3,4- or 1-cyanato-3,5-dimethylbenzene, cyanatoethylbenzene, cyanatobutylbenzene, cyanatooctylbenzene, cyanatononylbenzene, 2- ( 4-cyanphenyl) -2-phenylpropane (cyanate of 4-α-cumylphenol), 1-cyanato-4-cyclohexylbenzene, 1-cyanato-4-vinylbenzene, -Cyanato-2- or 1-cyanato-3-chlorobenzene, 1-cyanato-2,6-dichlorobenzene, 1-cyanato-2-methyl-3-chlorobenzene, cyanatonitrobenzene, 1-cyanato-4-nitro-2 -Ethylbenzene, 1-cyanato-2-methoxy-4-allylbenzene (eugenol cyanate), methyl (4-cyanatophenyl) sulfide, 1-cyanato-3-trifluoromethylbenzene, 4-cyanatobiphenyl, 1- Cyanato-2- or 1-cyanato-4-acetylbenzene, 4-cyanatobenzaldehyde, 4-cyanatobenzoic acid methyl ester, 4-cyanatobenzoic acid phenyl ester, 1-cyanato-4-acetaminobenzene, 4-cyanato Benzophenone, 1-cyanato-2,6-di-tert-butyl Tylbenzene, 1,2-dicyanatobenzene, 1,3-dicyanatobenzene, 1,4-dicyanatobenzene, 1,4-dicyanato-2-tert-butylbenzene, 1,4-dicyanato-2,4-dimethyl Benzene, 1,4-dicyanato-2,3,4-dimethylbenzene, 1,3-dicyanato-2,4,6-trimethylbenzene, 1,3-dicyanato-5-methylbenzene, 1-cyanato or 2-si Anatonaphthalene, 1-cyanato-4-methoxynaphthalene, 2-cyanato-6-methylnaphthalene, 2-cyanato-7-methoxynaphthalene, 2,2′-dicyanato-1,1′-binaphthyl, 1,3-, 1, 4-, 1,5-, 1,6-, 1,7-, 2,3-, 2,6- or 2,7-dicyanatosinaphthalene, 2,2'- or 4,4'-dicyanatobiff Enyl, 4,4′-dicyanatooctafluorobiphenyl, 2,4′- or 4,4′-dicyanatodiphenylmethane, bis (4-cyanato-3,5-dimethylphenyl) methane, 1,1-bis (4 -Cyanatophenyl) ethane, 1,1-bis (4-cyanatophenyl) propane, 2,2-bis (4-cyanatophenyl) propane, 2,2-bis (4-cyanato-3-methylphenyl) Propane, 2,2-bis (2-cyanato-5-biphenylyl) propane, 2,2-bis (4-cyanatophenyl) hexafluoropropane, 2,2-bis (4-cyanato-3,5-dimethyl) Phenyl) propane, 1,1-bis (4-cyanatophenyl) butane, 1,1-bis (4-cyanatophenyl) isobutane, 1,1-bis (4-cyanatophenyl) penta 1,1-bis (4-cyanatophenyl) -3-methylbutane, 1,1-bis (4-cyanatophenyl) -2-methylbutane, 1,1-bis (4-cyanatophenyl) -2, 2-dimethylpropane, 2,2-bis (4-cyanatophenyl) butane, 2,2-bis (4-cyanatophenyl) pentane, 2,2-bis (4-cyanatophenyl) hexane, 2,2 -Bis (4-cyanatophenyl) -3-methylbutane, 2,2-bis (4-cyanatophenyl) -4-methylpentane, 2,2-bis (4-cyanatophenyl) -3,3-dimethyl Butane, 3,3-bis (4-cyanatophenyl) hexane, 3,3-bis (4-cyanatophenyl) heptane, 3,3-bis (4-cyanatophenyl) octane, 3,3-bis ( 4-cyanatophenyl) 2-methylpentane, 3,3-bis (4-cyanatophenyl) -2-methylhexane, 3,3-bis (4-cyanatophenyl) -2,2-dimethylpentane, 4,4-bis (4 -Cyanatophenyl) -3-methylheptane, 3,3-bis (4-cyanatophenyl) -2-methylheptane, 3,3-bis (4-cyanatophenyl) -2,2-dimethylhexane, 3 , 3-bis (4-cyanatophenyl) -2,4-dimethylhexane, 3,3-bis (4-cyanatophenyl) -2,2,4-trimethylpentane, 2,2-bis (4-si Anatophenyl) -1,1,1,3,3,3-hexafluoropropane, bis (4-cyanatophenyl) phenylmethane, 1,1-bis (4-cyanatophenyl) -1-phenylethane, bis (4-cyanatofe Nyl) biphenylmethane, 1,1-bis (4-cyanatophenyl) cyclopentane, 1,1-bis (4-cyanatophenyl) cyclohexane, 2,2-bis (4-cyanato-3-isopropylphenyl) propane 1,1-bis (3-cyclohexyl-4-cyanatophenyl) cyclohexane, bis (4-cyanatophenyl) diphenylmethane, bis (4-cyanatophenyl) -2,2-dichloroethylene, 1,3-bis [ 2- (4-Cyanatophenyl) -2-propyl] benzene, 1,4-bis [2- (4-cyanatophenyl) -2-propyl] benzene, 1,1-bis (4-cyanatophenyl) -3,3,5-trimethylcyclohexane, 4- [bis (4-cyanatophenyl) methyl] biphenyl, 4,4-dicyanatobenzophenone, , 3-bis (4-cyanatophenyl) -2-propen-1-one, bis (4-cyanatophenyl) ether, bis (4-cyanatophenyl) sulfide, bis (4-cyanatophenyl) sulfone, 4-cyanatobenzoic acid-4-cyanatophenyl ester (4-cyanatophenyl-4-cyanatobenzoate), bis- (4-cyanatophenyl) carbonate, 1,3-bis (4-cyanatophenyl) adamantane 1,3-bis (4-cyanatophenyl) -5,7-dimethyladamantane, 3,3-bis (4-cyanatophenyl) isobenzofuran-1 (3H) -one (cyanate of phenolphthalein), 3,3-bis (4-cyanato-3-methylphenyl) isobenzofuran-1 (3H) -one (cyanate of o-cresolphthalein) G), 9,9′-bis (4-cyanatophenyl) fluorene, 9,9-bis (4-cyanato-3-methylphenyl) fluorene, 9,9-bis (2-cyanato-5-biphenylyl) Fluorene, tris (4-cyanatophenyl) methane, 1,1,1-tris (4-cyanatophenyl) ethane, 1,1,3-tris (4-cyanatophenyl) propane, α, α, α ′ -Tris (4-cyanatophenyl) -1-ethyl-4-isopropylbenzene, 1,1,2,2-tetrakis (4-cyanatophenyl) ethane, tetrakis (4-cyanatophenyl) methane, 2,4 , 6-Tris (N-methyl-4-cyanatoanilino) -1,3,5-triazine, 2,4-bis (N-methyl-4-cyanatoanilino) -6- (N-methylanilino) -1,3,5 − Liazine, bis (N-4-cyanato-2-methylphenyl) -4,4′-oxydiphthalimide, bis (N-3-cyanato-4-methylphenyl) -4,4′-oxydiphthalimide, bis ( N-4-cyanatophenyl) -4,4′-oxydiphthalimide, bis (N-4-cyanato-2-methylphenyl) -4,4 ′-(hexafluoroisopropylidene) diphthalimide, tris (3 5-dimethyl-4-cyanatobenzyl) isocyanurate, 2-phenyl-3,3-bis (4-cyanatophenyl) phthalimidine, 2- (4-methylphenyl) -3,3-bis (4-cyanato) Phenyl) phthalimidine, 2-phenyl-3,3-bis (4-cyanato-3-methylphenyl) phthalimidine, 1-methyl-3,3-bis (4-cyanatofe) L) Indoline-2-one, 2-phenyl-3,3-bis (4-cyanatophenyl) indoline-2-one, phenol novolac resin or cresol novolac resin (by known methods, phenol, alkyl-substituted phenol or halogen) Substituted phenol and formaldehyde compounds such as formalin and paraformaldehyde in an acidic solution), phenol aralkyl resin, cresol aralkyl resin, naphthol aralkyl resin, biphenyl aralkyl resin, phenol-modified xylene formaldehyde resin (by known methods) , Xylene formaldehyde resin and phenol compound reacted in the presence of an acidic catalyst) and phenol resin such as phenol-modified dicyclopentadiene resin by the same method as above. A phenol resin having a polynaphthylene ether structure (a polyhydric hydroxynaphthalene compound having two or more phenolic hydroxy groups in one molecule was subjected to dehydration condensation in the presence of a basic catalyst by a known method. Although the thing etc. which cyanate-ized the thing) are mentioned, it does not restrict | limit in particular. These cyanate ester compounds can be used alone or in combination.

As the epoxy resin, generally known compounds can be used as long as they are compounds having two or more epoxy groups in one molecule. For example, bisphenol A type epoxy resin, bisphenol E type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol A novolac type epoxy resin, biphenyl type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, Xylene novolac type epoxy resin, naphthalene type epoxy resin, anthracene type epoxy resin, trifunctional phenol type epoxy resin, tetrafunctional phenol type epoxy resin, triglycidyl isocyanurate, glycidyl ester type epoxy resin, alicyclic epoxy resin, dicyclopentadiene Novolac epoxy resin, biphenyl novolac epoxy resin, phenol aralkyl novolac epoxy resin, naphthol aralkyl novo -Type epoxy resin, aralkyl novolak type epoxy resin, biphenyl aralkyl type epoxy resin, naphthol aralkyl type epoxy resin, dicyclopentadiene type epoxy resin, polyol type epoxy resin, alicyclic epoxy resin, or halides thereof It is done. These epoxy resins can be used alone or in combination.

As the oxetane resin, generally known oxetane resins can be used. For example, oxetane, 2-methyloxetane, 2,2-dimethyloxetane, 3-methyloxetane, alkyloxetane such as 3,3-dimethyloxetane, 3-methyl-3-methoxymethyloxetane, 3,3′-di (tri Fluoromethyl) perfluoxetane, 2-chloromethyloxetane, 3,3-bis (chloromethyl) oxetane, OXT-101 (trade name, manufactured by Toagosei Co., Ltd.), OXT-121 (trade name, manufactured by Toagosei Co., Ltd.) and the like. These oxetane resins can be used alone or in combination.

As the benzoxazine compound, generally known compounds can be used as long as they have two or more dihydrobenzoxazine rings in one molecule. For example, bisphenol A type benzoxazine BA-BXZ (trade name, manufactured by Konishi Chemical) bisphenol F type benzoxazine BF-BXZ (trade name, manufactured by Konishi Chemical), bisphenol S type benzoxazine BS-BXZ (trade name, manufactured by Konishi Chemical), etc. Can be mentioned. These benzoxazine compounds can be used alone or in combination.

As the compound having a polymerizable unsaturated group, generally known compounds can be used. For example, vinyl compounds such as ethylene, propylene, styrene, divinylbenzene, divinylbiphenyl, methyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, polypropylene glycol di (meth) acrylate, Mono- or polyhydric alcohol (meth) acrylates such as trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, bisphenol Epoxy (meth) acrylates such as A-type epoxy (meth) acrylate and bisphenol F-type epoxy (meth) acrylate, benzocyclobutene resin, (bis) male De resins. These compounds having an unsaturated group can be used alone or in combination.

In addition to the above-described compounds or resins, the curable resin composition in the present invention further contains a compound that catalyzes the polymerization of a cyanate ester, an epoxy resin, an oxetane resin, or a compound having a polymerizable unsaturated group. be able to. Examples of the polymerization catalyst include zinc octylate, zinc naphthenate, cobalt naphthenate, copper naphthenate, acetylacetone iron and the like, phenol compounds such as octylphenol and nonylphenol, alcohols such as 1-butanol and 2-ethylhexanol, 2 -Methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethyl Imidazole, imidazole derivatives such as 2-phenyl-4-methyl-5-hydroxymethylimidazole, dicyandiamide, benzyldimethylamine, amine compounds such as 4-methyl-N, N-dimethylbenzylamine, Honiumu phosphorus-compounds of. Also, peroxides such as epoxy-imidazole adduct compounds, benzoyl peroxide, p-chlorobenzoyl peroxide, di-t-butyl peroxide, diisopropyl peroxycarbonate, di-2-ethylhexyl peroxycarbonate, or azobis An azo compound such as isobutyronitrile may be used. Commercially available catalysts may be used, such as Amicure PN-23 (Ajinomoto Fine Techno Co., NovaCure HX-3721 (Asahi Kasei Co.), Fujicure FX-1000 (Fuji Kasei Kogyo Co., Ltd.), and the like. These catalysts can be used alone or in combination.

An inorganic filler can be used for the curable resin composition in the present invention. Examples of inorganic fillers that can be used include talc, fired clay, unfired clay, mica, E glass, A glass, NE glass, C glass, L glass, D glass, S glass, M glass G20, and short glass fiber (E glass). And glass fine powders such as T glass, D glass, S glass, and Q glass.), Hollow glass, spherical glass, silica, fused silica and other silicates, titanium oxide, alumina, gibbsite, boehmite, etc. Products, carbonates such as calcium carbonate, magnesium carbonate and hydrotalcite, hydroxides such as aluminum hydroxide, magnesium hydroxide and calcium hydroxide, sulfates or sulfites such as barium sulfate, calcium sulfate and calcium sulfite, boron Boric acid such as zinc oxide, barium metaborate, aluminum borate, calcium borate, sodium borate , Nitrides such as aluminum nitride, boron nitride, silicon nitride and carbon nitride, carbides such as silicon carbide, titanates such as strontium titanate and barium titanate, zinc molybdate, silicone composite powder, silicone resin powder, etc. It is done. One of these can be used alone, or two or more can be used in combination. Among these, silica, alumina, boron nitride, and silicon nitride are particularly preferable. These can be used by increasing the filling amount by mixing different shapes (spherical or crushed molds) or different sizes.

The inorganic filler may be further treated with a treatment agent for surface treatment in advance. As the treating agent, at least one compound selected from the group consisting of functional group-containing silanes, cyclic oligosiloxanes, organohalosilanes, and alkylsilazanes can be suitably used. Among these, the surface treatment of spherical silica using organohalosilanes and alkylsilazanes is suitable for hydrophobizing the silica surface, and improves the dispersibility of the spherical silica in the curable resin composition. It is preferable in terms of superiority.

Furthermore, the curable resin composition of the present invention may be a thermoplastic resin, a curing catalyst, a curing accelerator, a color pigment, an antifoaming agent, a surface conditioner, a flame retardant, an ultraviolet absorber, an antioxidant, if necessary. Contains known additives such as photopolymerization initiators, fluorescent brighteners, photosensitizers, dyes, pigments, thickeners, lubricants, flow regulators, dispersants, leveling agents, brighteners, polymerization inhibitors, etc. It may be. Moreover, you may contain the solvent as needed. These optional additives can be used alone or in combination.

As the solvent, generally known solvents can be used. For example, ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cellosolv solvents such as propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, methyl lactate, methyl acetate, ethyl acetate, butyl acetate, isoamyl acetate, ethyl lactate And ester solvents such as methyl methoxypropionate and methyl hydroxyisobutyrate, alcohol solvents such as methanol, ethanol, isopropanol and 1-ethoxy-2-propanol, and aromatic hydrocarbons such as toluene, xylene and anisole. It is done. These solvents can be used alone or in combination.

The curable resin composition in the present invention includes the above-described cyanate ester compound and, if necessary, other cyanate ester compounds, epoxy resins, oxetane resins, benzoxazine compounds, and / or polymerizable unsaturated groups. Can be obtained by mixing together with a solvent using a known mixer such as a high speed mixer, a nauter mixer, a ribbon blender, a kneader, an intensive mixer, a universal mixer, a dissolver, a static mixer, etc. it can. The mixing method of the cyanate ester compound, various additives, and the solvent during mixing is not particularly limited.

The curable resin composition according to the present invention can be made into a cured product by curing with heat or light. The cured product can be obtained by melting the curable resin composition or dissolving it in a solvent, then pouring it into a mold and curing it under normal conditions. In the case of thermosetting, if the curing temperature is too low, curing does not proceed, and if it is too high, the cured product is deteriorated. Therefore, it is preferably in the range of 120 ° C to 300 ° C.

<Use of curable resin composition>
A sealing material can be produced using the curable resin composition of the present invention. As a method for producing the sealing material, generally known methods can be appropriately applied and are not particularly limited. For example, a sealing material can be manufactured by mixing the above-described curable resin composition and various known additives or solvents for sealing material applications using a known mixer. In addition, the mixing method of the cyanate ester compound, various additives, and the solvent at the time of mixing can generally apply a well-known method suitably, and is not specifically limited.

Moreover, a prepreg can be manufactured by impregnating or apply | coating the curable resin composition of this invention to an inorganic and / or organic fiber base material.

The base material is not particularly limited, but glass fiber base materials such as glass woven fabric and glass nonwoven fabric, polyamide resin fibers, aromatic polyamide resin fibers, polyamide resin fibers such as wholly aromatic polyamide resin fibers, polyester resin fibers, Synthetic fiber substrate, kraft paper, cotton linter composed of woven or non-woven fabric mainly composed of polyester resin fiber such as aromatic polyester resin fiber, wholly aromatic polyester resin fiber, polyimide resin fiber, fluororesin fiber, etc. Examples thereof include organic fiber base materials such as paper base materials mainly composed of paper, mixed paper of linter and kraft pulp, and the like. These known materials can be appropriately selected and used according to the performance required for the prepreg, for example, strength, water absorption, thermal expansion coefficient, and the like.

Although the glass which comprises the said glass fiber base material is not specifically limited, For example, E glass, C glass, A glass, S glass, D glass, NE glass, T glass, H glass etc. are mentioned.

The method for producing the prepreg is not particularly limited, and generally known methods can be appropriately applied. For example, a resin varnish is prepared using the curable resin composition described above, and a method of immersing the substrate in the resin varnish, a method of applying with various coaters, a method of spraying with a spray, etc. are applied to produce a prepreg. Can do. Among these, the method of immersing the base material in the resin varnish is preferable. Thereby, the impregnation property of the resin composition with respect to a base material can be improved. In addition, when a base material is immersed in a resin varnish, a normal impregnation coating equipment can be used. For example, a method of manufacturing a prepreg by impregnating a resin composition varnish into an inorganic and / or organic fiber base material, drying, forming a B-stage, and the like can be applied.

Moreover, the curable resin composition of this invention can also be used for a metal-clad laminated board and a multilayer board use. As a method for producing these laminated plates and the like, generally known ones can be appropriately applied and are not particularly limited. For example, a laminate can be obtained by laminating the above prepreg and a metal foil and then heat-pressing the laminate. At this time, although the temperature to heat is not specifically limited, 65-300 degreeC is preferable normally and 120-270 degreeC is more preferable. Moreover, the pressure to pressurize is not particularly limited, but usually 2 to 5 MPa is preferable, and 2.5 to 4 MPa is more preferable.

Moreover, a fiber reinforced composite material can be manufactured using the curable resin composition by this invention. As the reinforcing fibers, carbon fibers, glass fibers, aramid fibers, boron fibers, PBO fibers, high-strength polyethylene fibers, alumina fibers, silicon carbide fibers, and the like can be used. The form and arrangement of the reinforcing fibers are not particularly limited, and can be appropriately selected from woven fabrics, nonwoven fabrics, mats, knits, braids, unidirectional strands, rovings, choppeds, and the like. In addition, as a form of the reinforcing fiber, a preform (a laminate of woven fabrics made of reinforcing fibers, or a structure obtained by stitching them together with stitch yarn, or a fiber structure such as a three-dimensional woven fabric or a braided fabric) is applied. You can also. Specific examples of methods for producing these fiber-reinforced composite materials include a liquid composite molding method, a resin film infusion method, a filament winding method, a hand layup method, and a pultrusion method. Among these, the resin transfer molding method, which is one of the liquid composite molding methods, is to set materials other than preforms such as metal plates, foam cores, and honeycomb cores in the mold in advance. Therefore, it can be used in various applications, and is therefore preferably used when a composite material having a relatively complicated shape is mass-produced in a short time.

Since the curable resin composition according to the present invention has excellent low thermal expansion, flame retardancy and heat resistance, it is extremely useful as a highly functional polymer material, and is excellent in thermal, electrical and mechanical properties. As well as electrical insulation materials, sealing materials, adhesives, laminate materials, resists, build-up laminate materials, civil engineering / architecture, electricity / electronics, automobiles, railways, ships, aircraft, sporting goods, arts / crafts, etc. It is preferably used for a fixing material, a structural member, a reinforcing agent, a molding material in the field. Among these, it is suitable for electrical insulating materials, semiconductor encapsulating materials, adhesives for electronic components, aircraft structural members, satellite structural members, and railway vehicle structural members that require low thermal expansion, flame resistance, and high mechanical strength. is there.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not particularly limited by the following examples.

(Measurement of OH group (g / eq.) Equivalent of hydroxyl group-containing aromatic compound)
Based on JIS-K0070, the OH group equivalent (g / eq.) Was determined by the pyridine-acetyl chloride method.

(Measurement of weight average molecular weight Mn of cyanate ester compound)
10 μL of a solution in which 1 g of cyanate ester compound was dissolved in 100 g of tetrahydrofuran (solvent) was injected into high performance liquid chromatography (high performance liquid chromatograph LachromElite manufactured by Hitachi High-Technologies Corporation) for analysis. Two columns are TSKgel GMH _HR- M (length 30 cm × inner diameter 7.8 mm) manufactured by Tosoh Corporation, the mobile phase is tetrahydrofuran, and the flow rate is 1 mL / min. The detector is RI. The weight average molecular weight Mn was determined using polystyrene as a standard substance by the GPC method.

(Example 1) Synthesis of a cyanate ester compound (9) of a hydroxyl group-containing aromatic compound obtained by polycondensation of a hydroxy-substituted aromatic compound, an aromatic aldehyde compound and an aralkyl compound

Hydroxyl group-containing aromatic compound 1 represented by formula (10) (SK HE510 OH group equivalent 151 g / eq.) 370 g and triethylamine 372.1 g (3.68 mol) (based on 1 mol of hydroxy group, manufactured by Air Water Co., Ltd.) 1.5 mol) was dissolved in 2280 g of dichloromethane.
334.6 g (5.44 mol) of cyanogen chloride (2.2 mol with respect to 1 mol of hydroxy groups), 780.8 g of dichloromethane, 523.2 g (5.17 mol) of 36% hydrochloric acid (2. 1 mol) and 3233.4 g of water were poured over 50 minutes with stirring while maintaining the liquid temperature at -2 to -0.5 ° C. After the completion of 1 solution pouring, the mixture was stirred at the same temperature for 30 minutes, and then 297.7 g (2.94 mol) of triethylamine (1.2 mol relative to 1 mol of hydroxy group) was dissolved in 298 g of dichloromethane (solution 2). ) Was poured over 30 minutes. After the end of pouring the solution 2, the reaction was completed by stirring at the same temperature for 30 minutes.
Thereafter, the reaction solution was allowed to stand to separate an organic phase and an aqueous phase. The obtained organic phase was washed 6 times with 2000 g of water. The electric conductivity of the waste water in the fifth washing with water was 20 μS / cm, and it was confirmed that the ionic compounds that could be removed were sufficiently removed by washing with water.
The organic phase after washing with water was concentrated under reduced pressure, and finally concentrated to dryness at 90 ° C. for 1 hour to obtain 410 g of the intended cyanate ester compound (9) (brown viscous product). The number average molecular weight Mn of the obtained cyanate ester compound 1 was 364. Further, the IR spectrum of the cyanate ester compound (9) showed an absorption of 2261 cm ⁻¹ (cyanato group). An IR chart is shown in FIG.

(Example 2) Synthesis of cyanate ester compound (11) of a hydroxyl group-containing aromatic compound obtained by polycondensation of a hydroxy-substituted aromatic compound, an aromatic aldehyde compound and an aralkyl compound
Instead of the hydroxyl group-containing aromatic compound 1 represented by the formula (10), the hydroxyl group-containing aromatic compound 2 represented by the formula (12) (SK HE610 OH group equivalent 184 g / eq. Manufactured by Air Water Co., Ltd.) 440 g of the intended cyanate ester compound (11) (brown viscous material) was obtained in the same manner as in Example 1 except that 450 g was used. The number average molecular weight Mn of the obtained cyanate ester compound 2 was 377. Further, the IR spectrum of the cyanate ester compound (11) showed an absorption of 2262 cm ⁻¹ (cyanato group). An IR chart is shown in FIG.

Synthesis Example 1 Synthesis of a hydroxyl group-containing aromatic compound 3 obtained by polycondensation of a hydroxy-substituted aromatic compound, an aromatic aldehyde compound and an aralkyl compound represented by the formula (13)
In a four-necked flask equipped with a stirrer, thermometer, condenser and nitrogen gas insertion pipe, 620 parts by weight of phenol, 208 parts by weight of benzaldehyde, 53 parts by weight of salicylaldehyde, 350 parts by weight of p-xylylene glycol dimethyl ether and p-toluenesulfone 2 parts by weight of acid (monohydrate) was added, and the mixture was heated to 100 to 150 ° C., and the reaction was carried out while dehydration and demethanol were carried out until generation of these condensation by-products was not observed. Thereafter, unreacted phenol in the system was removed by distillation under reduced pressure to obtain 620 parts by weight of the phenol-based polymer 3. The hydroxyl group-containing aromatic compound 3 represented by the formula (13) thus obtained has an OH group equivalent of 139 g / eq. was.

(Example 3) Synthesis of a cyanate ester compound (14) of a hydroxyl group-containing aromatic compound obtained by polycondensation of a hydroxy-substituted aromatic compound, an aromatic aldehyde compound and an aralkyl compound
Instead of the hydroxyl group-containing aromatic compound 1 represented by the formula (10), the same procedure as in Example 1 was conducted except that 450 g of the hydroxyl group-containing aromatic compound 3 represented by the formula (13) synthesized in Synthesis Example 1 was used. As a result, 440 g of the intended cyanate ester compound (14) (brown viscous product) was obtained. The number average molecular weight Mn of the obtained cyanate ester compound 2 was 350. The IR spectrum of the cyanate ester compound (14) showed an absorption of 2262 cm ⁻¹ (cyanato group). An IR chart is shown in FIG.

Example 4
<Preparation of curing>
100 parts by mass of the cyanate ester compound (9) obtained in Example 1 was put into a separable flask, heated, stirred and mixed at 150 ° C. while degassing with a vacuum pump, and then JIS-K7238-2- It was poured into a mold described in 2009, placed in an oven, and cured by heating at 150 ° C. for 1 hour and then at 220 ° C. for 6 hours to obtain a cured product having a side of 100 mm and a thickness of 2 mm.

(Example 5)
Instead of using 100 parts by mass of the cyanate ester compound (9) obtained in Example 1, the same as Example 4 except that 100 parts by mass of the cyanate ester compound (11) obtained in Example 2 was used. A cured product was obtained.

(Example 6)
Instead of using 100 parts by mass of the cyanate ester compound (9) obtained in Example 1, the same as Example 4 except that 100 parts by mass of the cyanate ester compound (14) obtained in Example 3 was used. A cured product was obtained.

(Comparative Example 1)
In Example 4, instead of using 100 parts by mass of the cyanate ester compound (9), 100 parts by mass of 2,2-bis (4-cyanatophenyl) propane (trade name skylex manufactured by Mitsubishi Gas Chemical) was used. Obtained a cured product in the same manner as in Example 4.

<Evaluation of cured product>
The characteristics of each cured product obtained as described above were evaluated by the following methods.
Glass transition temperature (Tg): Based on JIS-K7244-3, using a dynamic viscoelasticity measuring device (AR2000 manufactured by TA Instruments Japan Co., Ltd.), start temperature 30 ° C., end temperature 400 ° C., Dynamic viscoelasticity was measured at a heating rate of 3 ° C./min and a measurement frequency of 1 Hz, and the maximum value of the loss tangent (tan δ) obtained at that time was taken as the glass transition temperature.
Thermal expansion coefficient: In accordance with JIS-K-7197-2012, using a thermomechanical analyzer (TMA / SS7100 manufactured by SII Nano Technology Co., Ltd.), test piece 5 mm × 5 mm × 2 mm, start temperature 30 ° C., end Thermomechanical analysis in expansion / compression mode was performed at a temperature of 330 ° C., a heating rate of 10 ° C./min, and a weight of 0.05 N (49 mN), and the average thermal expansion per 1 ° C. was measured at 60 to 120 ° C. .
Water absorption rate (%): Based on JIS-K7209-2000, method A, the saturated water absorption rate when immersed in water at 23 ° C. was determined.
Weight reduction rate (%): Based on JIS-K7120-1987, using a differential thermothermal gravimetric simultaneous measurement device (TG / DTA6200, manufactured by SII Nanotechnology Co., Ltd.), test piece 3 mm × 3 mm × 1.5 mm, start The weight was measured at a temperature of 30 ° C., an end temperature of 500 ° C., a heating rate of 10 ° C./min, and a nitrogen atmosphere, and the weight reduction rate at 450 ° C. was calculated based on the following equation.
Weight reduction rate (%) = (I−J) / I × 100
I represents the weight at the starting temperature and J represents the weight at 450 ° C.
Here, the flame retardancy in the present invention is defined as a large amount of residue during pyrolysis, that is, a low weight reduction rate.
Long-term heat resistance: The cured product prepared by the above method was stored in a hot air oven in an air atmosphere at 250 ° C. for 360 hours, and the glass transition temperature after storage was measured. A glass transition temperature decrease of 20% or less was accepted, and a glass transition temperature exceeding 20% was rejected.
The evaluation results are shown in Table 1.

As is clear from Table 1, the cured product of the curable resin composition using the cyanate compound of the present invention has a low coefficient of thermal expansion and excellent difficulty compared to those using a conventional cyanate compound. It was confirmed to have flammability and heat resistance.

Claims (13)

A cyanate ester compound represented by the following general formula (1).
(In the formula, Ar ¹ represents an aryl group, R ¹ represents a monovalent substituent, each independently represents a hydrogen atom, an alkyl group or an aryl group. Ar ² each independently represents a phenylene group, a naphthylene group, or .Ar ³ each independently phenylene group representing a biphenylene group, .R ² representing a naphthylene group or a biphenylene group denotes a monovalent substituent, each independently represent a hydrogen atom, an alkyl group, an aryl group, or cyanato group. n represents the number of bonds of the cyanate group to Ar ^{1 and} is an integer of ¹ to 3. m represents the number of bonds of R ^{1 obtained} by subtracting n from the number of bonds that Ar ¹ has, and p represents R ^{2 to} Ar ³ . Represents an integer of 1 to 5. x is an integer of 1 to 40. y is an integer of 1 to 20. Each repeating unit of x and y may be consecutively arranged. , Each other alternately or randomly It may be Idei.) The cyanate ester compound according to claim ¹ , wherein Ar ¹ , Ar ^2, and Ar ³ are each independently a phenylene group or a biphenylene group. The cyanate ester compound according to claim ^2, wherein Ar ¹ , Ar ² and Ar ³ are phenylene groups. The cyanate ester compound according to claim 2, wherein Ar ¹ and Ar ³ are phenylene groups, and Ar ² is a biphenylene group. A hydroxyl group-containing aromatic compound obtained by polycondensation of a hydroxy-substituted aromatic compound, an aromatic aldehyde compound and an aralkyl compound represented by the following general formula (2), wherein the structure is represented by the following general formula (3) A cyanate ester compound obtained by cyanating a hydroxyl group-containing aromatic compound having a cyanide with cyanogen halide.
(In the formula, each Ar ⁴ independently represents a phenylene group, a naphthylene group or a biphenylene group, and X represents an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group or a halogen atom.)
(In the formula, Ar ¹ represents an aryl group, R ¹ represents a monovalent substituent, each independently represents a hydrogen atom, an alkyl group or an aryl group. Ar ² each independently represents a phenylene group, a naphthylene group, or .Ar ³ each independently phenylene group representing a biphenylene group, .R ² representing a naphthylene group or a biphenylene group denotes a monovalent substituent, each independently represent a hydrogen atom, an alkyl group, an aryl group, or cyanato group. n ′ represents the number of bonded hydroxyl groups and is an integer of ¹ to ^3. m represents the number of bonded R ^{1 obtained} by subtracting n from the number of bonds that Ar ¹ has, and p represents the number of bonded R ^{2 to} Ar ³ . Represents an integer of 1 to 5. x is an integer of 1 to 40. y is an integer of 1 to 20. Even if each repeating unit of x and y is continuously arranged, They may be arranged alternately or randomly.   Curable resin composition containing the cyanate ester compound as described in any one of Claims 1-5.   Furthermore, at least 1 selected from the group consisting of a cyanate ester compound other than the cyanate ester compound according to claim 1, an epoxy resin, an oxetane resin, and a compound having a polymerizable unsaturated group. The curable resin composition of Claim 6 containing a seed or more.   Furthermore, the curable resin composition of Claim 6 or 7 containing an inorganic filler.   Hardened | cured material formed by hardening the curable resin composition as described in any one of Claims 6-8.   The sealing material containing the curable resin composition as described in any one of Claims 6-8.   A prepreg for a structural material, wherein the curable resin composition according to any one of claims 6 to 8 is impregnated or applied to a substrate and dried.   A fiber-reinforced composite material comprising the curable resin composition according to any one of claims 6 to 8.   The adhesive agent containing the curable resin composition as described in any one of Claims 6-8.