JP6602016B2 - Cyanate ester compound, curable resin composition containing the compound, and cured product thereof - Google Patents

Description

  The present invention relates to a 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.

  For example, in the field of semiconductor package materials, there is a problem that warpage occurs due to a mismatch in thermal expansion coefficient between the semiconductor chip and the substrate material as the substrate becomes thinner. As means for solving this, it is required to improve low thermal expansion and high heat resistance of the functional polymer material itself used for the substrate material. In addition, the use of lead-free solder is promoted for soldering a printed wiring board in consideration of the human body and the environment. In view of the ability to withstand the reflow process at a high temperature associated therewith, it is required to improve the low thermal expansion and high heat resistance of the functional polymer material itself.

  Further, from the viewpoint of enhancing the flame retardancy of the functional polymer material, conventionally, the functional polymer material may contain a halogen atom or a phosphorus atom. However, the halogen atom may generate a halogen-based gas that may cause environmental pollution during combustion, and lowers the insulation of the final product. In addition, phosphorus atoms often reduce required physical properties other than flame retardancy (heat resistance, moisture resistance, low water absorption, etc.). Therefore, it is also required to improve the flame retardancy without containing a halogen atom and a phosphorus atom in the functional polymer material.

  Furthermore, when manufacturing a laminated board for printed wiring board applications, etc., first, a monomer before curing, which is a precursor of a functional polymer material, is dissolved in a solvent such as methyl ethyl ketone, and then a varnish is prepared. A prepreg is produced by impregnating the fiber and drying it. Therefore, it is also required to improve solvent solubility for the monomer.

  In the field of semiconductor encapsulating materials, with the aim of reducing power loss (energy saving), studies are underway to replace semiconductor elements from silicon (Si) to wide gap semiconductors such as silicon carbide (SiC). Since SiC semiconductors are chemically more stable than Si semiconductors, high temperature operation exceeding 200 ° C. is possible, and miniaturization of devices is expected. Accordingly, a composition containing a functional polymer material used for a sealing material is required to have heat resistance, low thermal expansion, and long-term high-temperature heat resistance (hereinafter referred to as long-term heat resistance). ing.

  As an example of obtaining a cured product of a cyanate ester compound having low thermal expansion and heat resistance, a bifunctional cyanatophenyl type in which methylene group hydrogen bonding between cyanatophenyl groups is substituted with a specific alkyl group. It has been proposed to use a cyanate ester compound (1,1-bis (4-cyanatophenyl) isobutane) (see Patent Document 1). However, in a bifunctional cyanatophenyl type cyanate ester compound, if the hydrogen of the methylene group that binds the cyanatophenyl groups is replaced with an alkyl group, the flame retardancy (hard decomposition at high temperatures) is reduced. . In addition, Patent Document 1 has no description regarding flame retardancy and long-term heat resistance.

  As an example of obtaining a cured product of a cyanate ester compound having low thermal expansion and flame retardancy, it has been proposed to use a cyanate ester compound having an aralkyl structure (see Patent Document 2). However, the cyanate ester compound having an aralkyl structure is hardly soluble in a solvent and is difficult to handle.

  Examples of obtaining a cured product of a cyanate ester compound having flame retardancy and / or heat resistance include an isocyanuric acid skeleton-containing cyanate ester compound (see Patent Document 3), a triazine skeleton-containing cyanate ester compound (patents) Reference 4), a bifunctional cyanatophenyl type cyanate ester compound in which hydrogen of a methylene group bonding cyanatophenyl groups is substituted with a biphenyl group (see Patent Document 5), cyanate compound of phenol-modified xylene formaldehyde resin (refer to Patent Document 5) Use of a trifunctional cyanatophenyl type (trisphenolalkane type) cyanate ester compound and a bifunctional cyanatophenyl type cyanate ester compound (see Patent Document 7) or bisphenol A Type cyanate ester compound with imide Combining rated containing cyanate ester compound (see Patent Document 8) it has been proposed. However, in any case, there is no description regarding the coefficient of thermal expansion, long-term heat resistance and / or solvent solubility.

  As a composition using a cyanate ester compound having heat resistance and heat resistance at a high temperature for a long period of time, a composition containing a novolac-type cyanate, a novolac-type phenol resin and an inorganic filler has been proposed (Patent Document 9). ). However, the long-term heat resistance test in Patent Document 9 is about 50 hours (250 ° C.), which is not sufficient as the test time. Moreover, there is no description about a coefficient of thermal expansion or solvent solubility.

International Publication No. 2012/057144 Pamphlet Japanese Patent No. 4407823 Japanese Patent No. 4654770 JP 2012-036114 A Japanese Patent No. 5104312 International Publication No. 2013/21869 Pamphlet Japanese Patent No. 2613056 JP 2010-180147 A JP 2013-053218 A

So far, a practical cured product of a cyanate ester compound having low thermal expansion, flame retardancy and heat resistance in a high dimension has not been obtained using a cyanate ester compound having solvent solubility.
An object of the present invention includes a novel cyanate ester compound having excellent solvent solubility, a low thermal expansion coefficient, and a cured product having excellent flame retardancy and heat resistance, and the compound It is to provide a curable resin composition and the like.

  The present inventors have found that a cyanate ester compound obtained by cyanating a furan ring-containing phenol novolak resin has excellent solvent solubility and excellent handleability, and curability using such a cyanate ester compound. The present inventors have found that the resin composition has a low coefficient of thermal expansion and can realize a cured product having excellent flame retardancy and heat resistance, and has reached the present invention. That is, the present invention is as follows.

1. A cyanate ester compound having a structure represented by the following general formula (1).
(In the formula, n represents an integer of 1 or more.)

  2. 1. Obtained by cyanating a furan ring-containing phenol novolac resin. The cyanate ester compound described in 1.

  3. 1. The furan ring-containing phenol novolac resin is obtained by reacting furfural with phenol in the presence of a basic catalyst. The cyanate ester compound described in 1.

  4). The weight average molecular weight Mw is 100-3500. ~ 3. The cyanate ester compound as described in any one of these.

  5.1. ~ 4. A curable resin composition comprising the cyanate ester compound according to any one of the above.

  6.1. ~ 4. At least 1 selected from the group consisting of a cyanate ester compound other than the cyanate ester compound according to any one of the above, a maleimide compound, a phenol resin, an epoxy resin, an oxetane resin, and a compound having a polymerizable unsaturated group. 4. further including species or more The curable resin composition described in 1.

  7.5. Or 6. A cured product obtained by curing the curable resin composition described in 1.

  8.5. Or 6. A prepreg for a structural material, which is obtained by impregnating or coating a curable resin composition described in 1 above on a substrate and drying.

  9.5. Or 6. A sealing material comprising the curable resin composition described in 1.

  10.5. Or 6. A fiber-reinforced composite material comprising the curable resin composition described in 1.

  11.5. Or 6. An adhesive comprising the curable resin composition described in 1.

The GPC chart of the furan ring containing phenol novolak resin obtained in Example 1. FIG. The GPC chart of the cyanate ester compound FPRCN obtained in Example 1. The FT-IR chart of the furan ring containing phenol novolak resin and cyanate ester compound FPCN obtained in Example 1. ¹ H-NMR spectrum of cyanate ester compound E-CN obtained in Example 2.

  The present invention is a cyanate ester compound obtained by cyanating a furan ring-containing phenol novolak resin, 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, and an adhesive are also provided. The

<Furan ring-containing phenol novolac resin>
The furan ring-containing phenol novolak resin used as the raw material of the cyanate ester compound of the present invention is not particularly limited as long as it is a novolak resin having a furan ring. For example, JP-A-10-237060 and JP-A-2007-2111254, etc. According to the method, it can be obtained by reacting furfural with phenol in the presence of a basic catalyst.

  Basic catalysts used for the reaction of furfural with phenol include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide, alkaline earth metal hydroxides such as magnesium hydroxide and calcium hydroxide, Examples thereof include alkali metal alkoxides such as sodium methoxide, sodium ethoxide, potassium methoxide, potassium ethoxide and potassium tert-butoxide, and alkaline earth metal alkoxides such as magnesium methoxide and magnesium ethoxide. These can be used alone or in combination of two or more.

  The usage-amount of the said basic catalyst is 0.005-2.0 mol normally with respect to 1 mol of phenol, Preferably it is 0.01-1.1 mol.

  In the reaction of furfural with phenol, a solvent inert to the reaction can be used as necessary. Examples of the solvent include organic solvents such as alcohol solvents such as methanol, ethanol, propanol and isopropanol, and aromatic hydrocarbon solvents such as toluene and xylene. These can be used alone or in combination of two or more. When using a solvent, the usage-amount is 5-500 mass parts normally with respect to 100 mass parts of phenol, Preferably it is 10-300 mass parts.

  The reaction temperature in the reaction is 0 to 200 ° C, preferably 50 to 150 ° C.

  The reaction time in the reaction is 1 to 200 hours, preferably 5 to 100 hours.

  In the said reaction, the usage-amount of phenol is 1.5-20 mol with respect to 1 mol of furfural, Preferably it is 1.8-10 mol.

  The reaction is performed by adding a basic catalyst to a mixture of furfural and phenol (optionally a solvent) and heating. Further, furfural may be gradually added to a place where a mixture of phenol and a catalyst (a solvent if necessary) is heated. The reaction may be performed with stirring, may be performed in air or in an inert atmosphere (such as nitrogen, helium, or argon), or may be performed at normal pressure or under pressure. The progress of the reaction can be confirmed (or traced) by high performance liquid chromatography (HPLC), thin layer chromatography (TLC) or the like.

  The reaction mixture after completion of the reaction contains unreacted furfural, unreacted phenol, basic catalyst, side reaction product and the like. Therefore, it may be separated and purified by a conventional method, for example, a separation means such as neutralization, washing with water, filtration, concentration, extraction, crystallization, recrystallization, column chromatography, or a combination of these.

  The furan ring-containing phenol novolak resin obtained by the above production method (although not particularly limited) can be represented by the following general formula (2).

(In the formula, n represents an integer of 1 or more. A mixture of compounds in which n is different may be used.)

<Cyanate ester compound>
The cyanate ester compound of the present invention can be obtained by cyanating the hydroxy group of the furan ring-containing phenol novolac resin. The cyanating method is not particularly limited, and a known method can be applied. Specifically, a method in which a furan ring-containing phenol novolak resin and cyanogen halide are reacted in a solvent in the presence of a basic compound. In the solvent, in the presence of a base, cyanogen halide is always present in excess of the base. As described above, a method of reacting a furan ring-containing phenol novolac resin with cyanogen halide (US Pat. No. 3,553,244), or using a tertiary amine as a base and using this in excess of cyanogen halide, the presence of a solvent. Below, after adding a tertiary amine to a furan ring-containing phenol novolac resin, a cyan halide is added dropwise, or a cyanide halide and a tertiary amine are added dropwise (Patent No. 3319061), continuous plug flow method Reaction of furan ring-containing phenol novolac resin, trialkylamine and cyanogen halide (Japanese Patent No. 3905559), a tert-ammonium halide produced as a by-product when a furan ring-containing phenol novolak resin and cyanogen halide are reacted in a non-aqueous solution in the presence of a tert-amine, and cation and anion exchange. A method of treating in pairs (Japanese Patent No. 4055210), a furan ring-containing phenol novolak resin, and in the presence of water and a solvent capable of liquid separation, a tertiary amine and a cyanogen halide were simultaneously added and reacted. Thereafter, it is washed and separated with water, and the resulting solution is precipitated and purified using a secondary or tertiary alcohol or a poor hydrocarbon solvent (Japanese Patent No. 299964), and further, a furan ring-containing phenol novolac resin, halogen To react cyanide and tertiary amine in a two-phase solvent of water and organic solvent under acidic conditions The (Patent 5,026,727 discloses) or the like to obtain a cyanate ester compound of the present invention.

When the above-described method of reacting a furan ring-containing phenol novolak resin and cyanogen halide in a solvent in the presence of a basic compound is used, the furan ring-containing phenol novolak resin as a reaction substrate is mixed with a cyanogen halide solution and a base. After dissolving in advance in any of the basic compound solutions, the cyanogen halide solution and the basic compound solution are brought into contact with each other.
As a method of contacting the cyanide halide solution and the basic compound solution (contact method), (A) a method of pouring the basic compound solution into the stirred cyanogen halide solution, and (B) stirring and mixing Examples thereof include a method in which a cyan halide solution is poured into the basic compound solution thus prepared, and a method (C) in which a cyan halide solution and a basic compound solution are continuously or alternately supplied.
Among the methods (A), (B) and (C), the side reaction is suppressed, and a higher purity cyanate ester compound can be obtained in a high yield, so the method (A) is preferred.
The method for contacting the cyanogen halide solution and the basic compound solution may be either 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 hydroxy group of the furan ring-containing phenol novolak resin, and a higher purity cyanate compound can be obtained in a high yield. Therefore, 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. Further, 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 of cyanogen halide used in the cyanation step of the present invention relative to the furan ring-containing phenol novolac resin is 0.5 to 5 mol, preferably 1.0 to 3 mol per mol of the hydroxyl group of the furan ring-containing phenol novolac resin. .5 moles.
The reason is to increase the yield of the cyanate ester compound without leaving unreacted furan ring-containing phenol novolak resin.

  Solvents used for the cyanogen halide solution include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and cyclopentanone, aliphatic hydrocarbon solvents such as n-hexane, cyclohexane and isooctane, benzene, toluene and xylene. Aromatic hydrocarbon solvents such as 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 Alcohol solvents such as methyl ether, 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, Examples include nitro solvents such as nitromethane and nitrobenzene, ester solvents such as ethyl acetate and ethyl benzoate, and aqueous solvents. These can be used alone or in combination of two or more according to the reaction substrate.

  As the basic compound used in the cyanate formation step of the present invention, any of organic and inorganic bases can be used, and one of them is used alone or in combination of two or more.

  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 preferably 0.1 to 8 mol, more preferably 1.0 to 3.5 mol, with respect to 1 mol of the hydroxy group of the furan ring-containing phenol novolac resin.
The reason is to increase the yield of the cyanate ester compound without leaving unreacted furan ring-containing phenol novolak resin.

  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 to be used is preferably 1.0 to 5.0 mol, more preferably 1.0 to 3.5 mol, per 1 mol of the hydroxy group of the furan ring-containing phenol novolac resin.
The reason is to increase the yield of the cyanate ester compound without leaving unreacted furan ring-containing phenol novolak resin.

  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 for the basic compound solution is preferably 0.1 to 100 parts by mass with respect to 1 part by mass of the furan ring-containing phenol novolac resin when the furan ring-containing phenol novolak resin is dissolved in the basic compound solution. More preferably, it is 0.5-50 mass parts.
When the furan ring-containing phenol novolak resin is not dissolved in the basic compound solution, the amount of the solvent used is preferably 0.1 to 100 parts by mass, more preferably 0.25 to 50, per 1 part by mass of the basic compound. Part 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, or an aromatic hydrocarbon type such as benzene, toluene, or xylene. Solvents, ether solvents such as diethyl ether, dimethyl cellosolve, diglyme, tetrahydrofuran, methyltetrahydrofuran, dioxane, tetraethylene glycol dimethyl ether, halogenated hydrocarbons such as dichloromethane, chloroform, carbon tetrachloride, dichloroethane, trichloroethane, chlorobenzene, bromobenzene Solvents, alcohol solvents such as methanol, ethanol, isopropanol, methylsolvosolve, propylene glycol monomethyl ether, N, N-dimethyl Aprotic polar solvents such as lumamide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidone, dimethyl sulfoxide, nitrile solvents such as acetonitrile and benzonitrile, nitro solvents such as nitromethane and nitrobenzene, ethyl acetate, benzoic acid Examples thereof include ester solvents such as ethyl acid and aliphatic hydrocarbon solvents such as cyclohexane. The organic solvent can be appropriately selected according to the basic compound, the reaction substrate, and the solvent used in the reaction. These can be used singly 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. . From the viewpoint of efficiently obtaining the desired cyanate ester compound, distilled water and deionized water with less impurities are preferred.

  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 a sufficient reaction rate. Of these, tertiary amines with few side reactions are preferred. The tertiary amine may be any of alkylamine, arylamine, and cycloalkylamine, and specifically, trimethylamine, triethylamine, tri-n-butylamine, triamylamine, diisopropylethylamine, diethyl-n-butylamine, methyldiamine. -N-butylamine, methylethyl-n-butylamine, dodecyldimethylamine, tribenzylamine, triethanolamine, N, N-dimethylaniline, N, N-diethylaniline, diphenylmethylamine, pyridine, diethylcyclohexylamine, tricyclohexyl Amines, 1,4-diazabicyclo [2.2.2] octane, 1,8-diazabicyclo [5.4.0] -7-undecene, and 1,5-diazabicyclo [4.3.0] -5 Nonen mentioned That. Among these, trimethylamine, triethylamine, tri-n-butylamine, and diisopropylethylamine are more preferable, and triethylamine is particularly preferable from the viewpoint of solubility in water and the ability to obtain the target product with higher yield. These are used singly or in combination of two or more.

  The total amount of the solvent used in the cyanate-forming step of the present invention is 2.5 to 100 parts by mass with respect to 1 part by mass of the furan ring-containing phenol novolac resin. From the viewpoint of more efficiently producing a cyanate ester compound.

In the cyanateization 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 a pH of less than 7. 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 efficiently produced. In order to maintain the pH of the reaction solution below 7, a method of adding an acid to the reaction solution is preferable. An acid is added to the cyanogen halide solution immediately before the cyanation step, and the acid is added to the reaction system while appropriately measuring the pH of the reaction solution with a pH meter during the reaction, and the pH is kept below 7 It is more preferable to do so.
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 volatilization of cyanogen chloride, the temperature is preferably -20 to + 50 ° C, more preferably -15 to 15 ° C, and still 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 reaction system.
Further, the reaction time is not particularly limited, but the pouring time when the contact method is (A) and (B) and the contact time when (C) are preferably 1 minute to 20 hours, preferably 3 minutes to 10 hours. Is more preferable. Furthermore, it is preferable to make it stir after that, maintaining the reaction temperature for 10 minutes to 10 hours.

  By setting the reaction conditions in the above range, the target cyanate ester compound can be obtained more economically and more 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 phase 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 can be employed. In order to remove water from the sufficiently washed reaction solution, it can be dried 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, it is possible to employ a method in which an ether solvent, a hydrocarbon solvent such as hexane, or an alcohol solvent is dropped into the reaction solution or back-dropped. 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. Crystallization may be performed by simply concentrating or cooling the reaction solution.

  The cyanate ester compound obtained by the above production method (although it is not particularly limited) can be represented by the following general formula (1).

(In the formula, n represents an integer of 1 or more. N may be a mixture of different compounds.)

  Although the weight average molecular weight Mw of the cyanate ester compound of this invention is not specifically limited, It is preferable that it is 100-3500, More preferably, it is 200-3000, More preferably, it is 200-2000.

  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 is a cyanate ester compound other than the above-described cyanate ester compounds (hereinafter referred to as “other cyanate ester compounds”), maleimide compounds, phenols, as long as desired characteristics are not impaired. A resin, an epoxy resin, an oxetane resin, a benzoxazine compound, and / or a compound having a polymerizable unsaturated group may be contained.

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 (3) is mentioned.
(In the formula, each Ar ₁ independently represents a phenylene group, a naphthylene group, or a biphenylene group, and when there are a plurality of Ar _{1 s} , they may be the same as or different from each other. A group in which an alkyl group having 6 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkyl group having 1 to 6 carbon atoms and an aryl group having 6 to 12 carbon atoms are bonded to each other; The aromatic ring in Ra may have a substituent, Ar ₁ and the substituent in Ra can be selected at any position, and p represents the number of cyanato groups bonded to Ar ₁ , and each independently represents 1 to 1 Q is an integer of 3. q represents the number of Ra bonded to Ar ₁ , 4-p when Ar ₁ is a phenylene group, 6-p when a naphthylene group, and 8-p when a biphenylene group. T represents the average number of repetitions and is an integer from 0 to 50. And X may be a mixture of compounds having different t. Each X is independently a single bond or a divalent organic group having 1 to 50 carbon atoms (a hydrogen atom may be substituted with a heteroatom). A divalent organic group having 1 to 10 nitrogen atoms (for example, —N—R—N— (where R represents an organic group)), a carbonyl group (—CO—), a carboxy group (—C (═O)) O—), a carbonyl dioxide group (—OC (═O) O—), a sulfonyl group (—SO ₂ —), or a divalent sulfur atom or a divalent oxygen atom.

The alkyl group in Ra in the general formula (3) may have any of a linear or branched chain structure and a cyclic structure (for example, a cycloalkyl group).
The hydrogen atom in the alkyl group in the general formula (3) and the aryl group in Ra may be substituted with a halogen atom such as a fluorine atom or a chlorine atom, an alkoxy group such as a methoxy group or a phenoxy group, a cyano group, or the like. Good.
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, etc. are 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 is exemplified. 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 X of the general formula (3) include an alkylene group such as a methylene group, an ethylene group, a trimethylene group, and a propylene group, a cyclopentylene group, a cyclohexylene group, and a trimethylcyclohexylene group. Examples thereof include divalent organic groups having an aromatic ring such as a cycloalkylene group, a biphenylylmethylene group, 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 a fluorine atom or a chlorine atom, 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 X of the general formula (3) include a group represented by —N—R—N—, an imino group, and a polyimide group.

Moreover, the specific structure as an organic group of X in General formula (3) also includes the bivalent group represented by the following general formula (4) or the following general formula (5).
(In the formula, Ar ₂ represents a phenylene group, a naphthylene group or a biphenylene group, and when u is 2 or more, they may be the same or different. Rb, Rc, Rf and Rg are each independently A hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, an trifluoromethyl group, or an aryl group having at least one phenolic hydroxy group, wherein Rd and Re are each independently a hydrogen atom; Or an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a hydroxy group, and u represents an integer of 0 to 5.)
(In the formula, Ar ₃ is selected from any one of a phenylene group, a naphthylene group, and a biphenylene group. Ri and Rj are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, and an aryl group having 6 to 12 carbon atoms. A group, a benzyl group, an alkoxy group having 1 to 4 carbon atoms, a hydroxy group, a trifluoromethyl group, or an aryl group substituted with at least one cyanato group, v represents an integer of 0 to 5. , V may be a mixture of different compounds.)

Furthermore, as X in General formula (3), the bivalent group represented by a following formula is mentioned.
(In the formula, m represents an integer of 4 to 7. Each R independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.)
Specific examples of Ar _{2 in the} general formula (4) and Ar _{3 in} the general formula (5) include 1,4-phenylene group, 1,3-phenylene group, 4,4′-biphenylene group, 2,4′- Biphenylene group, 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-naphthylene group, 1,3-naphthylene group, 1,4-naphthylene group, 2,7-naphthylene group and the like.
Rb to Rg in the general formula (4) and Ri and Rj in the general formula (5) have the same meanings as those in the general formula (3).

Specific examples of the cyanato-substituted aromatic compound represented by the general formula (3) 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-cyanatophenyl) -2-phenylpropane (cyanate of 4-α-cumylphenol), 1-cyanato-4-cyclohexylbenzene, 1-cyanato-4-vinylbenzene 1-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-si Anatobenzophenone, 1-cyanato-2,6-di-tert- Butylbenzene, 1,2-dicyanatobenzene, 1,3-dicyanatobenzene, 1,4-dicyanatobenzene, 1,4-dicyanato-2-tert-butylbenzene, 1,4-dicyanato-2,4- Dimethylbenzene, 1,4-dicyanato-2,3,4-trimethylbenzene, 1,3-dicyanato-2,4,6-trimethylbenzene, 1,3-dicyanato-5-methylbenzene, 1-cyanato or 2- Cyanatonaphthalene, 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'-dicyanate Biphenyl, 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) pe Tan, 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- Dimethylbutane, 3,3-bis (4-cyanatophenyl) hexane, 3,3-bis (4-cyanatophenyl) heptane, 3,3-bis (4-cyanatophenyl) octane, 3,3-bis (4-cyanatopheny ) -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 -Cyanatophenyl) -1,1,1,3,3,3-hexafluoropropane, bis (4-cyanatophenyl) phenylmethane, 1,1-bis (4-cyanatophenyl) -1-phenylethane Bis (4-cyanato Phenyl) 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-dicyanatobenzopheno 1,3-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, 1,3-bis (3-methyl-4-cyanatophenyl) -5,7-dimethyladamantane, 3,3 -Bis (4-cyanatophenyl) isobenzofuran-1 (3H) -one (cyanate of phenolphthalein), 3,3-bis (4-cyanato-3- Tilphenyl) isobenzofuran-1 (3H) -one (cyanate of o-cresolphthalein), 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-si Anatophenyl) 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-triazine, 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-cyanatophenyl) phthalimidine, 2-phenyl-3,3-bis (4-sia To-3-methylphenyl) phthalimidine, 1-methyl-3,3-bis (4-cyanatophenyl) indoline-2-one, 2-phenyl-3,3-bis (4-cyanatophenyl) indoline-2 -One, phenol novolak resin or cresol novolak resin (reacted phenol, alkyl-substituted phenol or halogen-substituted phenol with formaldehyde compounds such as formalin and paraformaldehyde in an acidic solution by a known method), trisphenol novolak Resin (reacted hydroxybenzaldehyde and phenol in the presence of an acidic catalyst), fluorene novolak resin (reacted fluorenone compound and 9,9-bis (hydroxyaryl) fluorene in the presence of an acidic catalyst ), Phenolic Alkyl resins, cresol aralkyl resin, a naphthol aralkyl resin and a biphenyl aralkyl resin (a known method, Ar 2 _- (a CH 2 _Y) bishalogenomethyl compounds represented by ₂ and a phenol compound with an acid catalyst or no catalyst Reaction product, bis (alkoxymethyl) compound represented by Ar _2- (CH ₂ OR) ₂ or bis (hydroxymethyl) compound represented by Ar _2- (CH ₂ OH) ₂ and phenol A compound obtained by reacting a compound in the presence of an acidic catalyst, or a product obtained by polycondensing an aromatic aldehyde compound, an aralkyl compound or a phenol compound), a phenol-modified xylene formaldehyde resin (by a known method, xylene formaldehyde resin and phenol) The compound was reacted in the presence of an acidic catalyst ), Modified naphthalene formaldehyde resin (reacted naphthalene formaldehyde resin and hydroxy-substituted aromatic compound in the presence of an acidic catalyst by a known method), phenol-modified dicyclopentadiene resin, phenol having a polynaphthylene ether structure A phenol resin such as a resin (a polyhydric hydroxynaphthalene compound having two or more phenolic hydroxy groups in one molecule by a known method and dehydrated in the presence of a basic catalyst) is used in the same manner as described above. Examples of the cyanate may be mentioned, but are not particularly limited. These other cyanate ester compounds can be used alone or in combination.

  As the maleimide compound, generally known compounds can be used as long as they have one or more maleimide groups in one molecule. Examples of maleimide compounds include o-phenylene bismaleimide, m-phenylene bismaleimide, p-phenylene bismaleimide, o-phenylene biscitraconimide, m-phenylene biscitraconimide, p-phenylene biscitraconimide, 4,4 ′. -Diphenylmethane bismaleimide, bis (3,5-dimethyl-4-maleimidophenyl) methane, bis (3-ethyl-5-methyl-4-maleimidophenyl) methane, bis (3,5-diethyl-4-maleimidophenyl) Methane, 2,2′-bis [4- (4-maleimidophenoxy) phenyl] propane, 4-methyl-1,3-phenylenebismaleimide, 1,6′-bismaleimide- (2,2,4-trimethyl) Hexane, 4,4-diphenyl ether bismaleimide, , 4-diphenylsulfone bismaleimide, 1,3-bis (3-maleimidophenoxy) benzene, 1,3-bis (4-maleimidophenoxy) benzene, 4,4'-diphenylmethane biscitraconimide, 2,2'-bis [4- (4-citraconimidophenoxy) phenyl] propane, bis (3,5-dimethyl-4-citraconimidophenyl) methane, bis (3-ethyl-5-methyl-4-citraconimidophenyl) methane, bis ( 3,5-diethyl-4-citraconimidophenyl) methane, polyphenylmethanemaleimide, prepolymers of these maleimide compounds, or prepolymers of the above maleimide compounds and amine compounds, etc., which are particularly limited is not. These maleimide compounds can be used alone or in combination.

  As a phenol resin, the phenol resin which has a 2 or more hydroxy group in 1 molecule is preferable, and a generally well-known thing can be used. Examples of the phenol resin include bisphenol A type phenol resin, bisphenol E type phenol resin, bisphenol F type phenol resin, bisphenol S type phenol resin, phenol novolac resin, bisphenol A novolac type phenol resin, glycidyl ester type phenol resin, and aralkyl novolac. Type phenol resin, biphenyl aralkyl type phenol resin, cresol novolac type phenol resin, polyfunctional phenol resin, naphthol resin, naphthol novolac resin, polyfunctional naphthol resin, anthracene type phenol resin, naphthalene skeleton modified novolak type phenol resin, phenol aralkyl type phenol Resin, naphthol aralkyl type phenol resin, dicyclopentadiene type phenol resin, Examples include phenyl type phenol resins, alicyclic phenol resins, polyol type phenol resins, phosphorus-containing phenol resins, polymerizable unsaturated hydrocarbon group-containing phenol resins, and hydroxyl group-containing silicone resins. . These phenol resins can be used individually by 1 type or in combination of 2 or more types.

  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. Examples of epoxy resins include bisphenol A type epoxy resins, bisphenol E type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, bisphenol A novolac type epoxy resins, biphenyl type epoxy resins, phenol novolac type epoxy resins, and cresol novolacs. 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, naphtha Aralkyl novolak 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. Can be mentioned. These epoxy resins can be used alone or in combination.

  Generally known oxetane resins can be used. Examples of the oxetane resin include alkyl oxetane such as oxetane, 2-methyloxetane, 2,2-dimethyloxetane, 3-methyloxetane, 3,3-dimethyloxetane, 3-methyl-3-methoxymethyloxetane, 3,3. In addition to '-di (trifluoromethyl) perfluoxetane, 2-chloromethyloxetane, and 3,3-bis (chloromethyl) oxetane, commercially available products such as OXT-101 (trade name, manufactured by Toagosei Co., Ltd.) and OXT- 121 (trade name of Toagosei Co., Ltd.). These oxetane resins can be used alone or in combination.

  As the benzoxazine compound, a compound having two or more dihydrobenzoxazine rings in one molecule is preferable, and generally known compounds can be used. Examples of the benzoxazine compound include BA-BXZ (trade name, manufactured by Konishi Chemical Co., Ltd.), which is a bisphenol A-type benzoxazine, and BF-BXZ (trade name, manufactured by Konishi Chemical Co., Ltd.), which is a bisphenol F-type benzoxazine, and bisphenol S-type benzoxazine. Examples include BS-BXZ (trade name, manufactured by Konishi Chemical) and phenolphthalein-type benzoxazine. These benzoxazine compounds can be used alone or in combination.

  As the compound having a polymerizable unsaturated group, generally known compounds can be used. Examples of the compound having a polymerizable unsaturated group include vinyl compounds such as ethylene, propylene, styrene, divinylbenzene, divinylbiphenyl, methyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl ( Monovalents such as (meth) acrylate, polypropylene glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate Or epoxy (meth) acrylates such as (meth) acrylates of polyhydric alcohols, bisphenol A type epoxy (meth) acrylates, bisphenol F type epoxy (meth) acrylates, etc. , Benzocyclobutene resins. These compounds having a polymerizable unsaturated group can be used alone or in combination. The “(meth) acrylate” is a concept including acrylate and methacrylate corresponding thereto.

  In the curable resin composition of the present invention, in addition to the above-described compounds and resins, a cyanate ester compound, a maleimide compound, a phenol resin, an epoxy resin, an oxetane resin, and a polymerization of a compound having a polymerizable unsaturated group A compound acting as a catalyst can be blended. Examples of the polymerization catalyst include metal salts such as zinc octylate, zinc naphthenate, cobalt naphthenate, copper naphthenate, and acetylacetone iron, phenol compounds such as octylphenol and nonylphenol, and 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- Imidazole derivatives such as dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, dicyandiamide, benzyldimethylamine, amine compounds such as 4-methyl-N, N-dimethylbenzylamine, phosphite Systems include phosphorus compounds phosphonium. 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 as a polymerization catalyst. Commercially available polymerization catalysts may be used. Examples of commercially available products include Amicure PN-23 (trade name, manufactured by Ajinomoto Fine Techno Co., Ltd.), Novacure HX-3721 (trade name, manufactured by Asahi Kasei Co., Ltd.), and Fujicure FX-1000. (Trade name manufactured by Fuji Kasei Kogyo Co., Ltd.). These polymerization 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 the inorganic filler 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, zinc oxide , Oxides such as magnesium oxide, zirconium oxide and molybdenum oxide, carbonates such as calcium carbonate, magnesium carbonate and hydrotalcite, hydroxides such as aluminum hydroxide, magnesium hydroxide and calcium hydroxide, barium sulfate and calcium sulfate , Sulfates or sulfites such as calcium sulfite, zinc borate, barium metaborate, boron Borates such as aluminum, calcium borate and 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, Examples thereof include zinc molybdate, silicone composite powder, and silicone resin powder. These inorganic fillers can be used individually by 1 type or in mixture of 2 or more types. 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. Examples of the solvent include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, cellosolv solvents such as propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate, methyl lactate, methyl acetate, ethyl acetate, butyl acetate and acetic acid. Ester solvents such as isoamyl, ethyl lactate, methyl methoxypropionate and methyl hydroxyisobutyrate, alcohol solvents such as methanol, ethanol, isopropanol and 1-ethoxy-2-propanol, and aromatic carbonization such as toluene, xylene and anisole Hydrogen etc. are mentioned. These solvent can be used individually by 1 type or in mixture of 2 or more types.

  The curable resin composition in the present invention includes the above-described cyanate ester compound and, if necessary, other cyanate ester compounds, maleimide compounds, phenol resins, epoxy resins, oxetane resins, benzoxazine compounds, and / or 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., with a solvent, a compound having a polymerizable unsaturated group and various additives. Can be obtained by mixing. 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, for example, 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, the curing temperature is preferably in the range of 120 ° C. to 300 ° C. from the viewpoint of further curing and suppressing the deterioration of the cured product.

<Use of curable resin composition>
The sealing material of the present invention contains the curable resin composition and can be produced using the curable resin composition. As a method for producing the sealing material, generally known methods can be appropriately applied and are not particularly limited. For example, the curable resin composition is mixed with various additives or solvents that are known to be used when producing a sealing material by using a known mixer. The material can be manufactured. In addition, the addition method of curable resin composition, various additives, and a solvent in the case of mixing can apply a generally well-known thing suitably, and is not specifically limited.

  The structural material prepreg of the present invention includes a base material and the curable resin composition impregnated or coated on the base material. The prepreg for a structural material can be produced by impregnating or applying the curable resin composition on an inorganic and / or organic fiber substrate and further drying as necessary.

  Although it does not specifically limit as a base material, For example, polyamide type | system | groups, such as inorganic fiber equipments, such as glass fiber base materials, such as a glass woven fabric and a glass nonwoven fabric, a polyamide resin fiber, an aromatic polyamide resin fiber, and a fully aromatic polyamide resin fiber Synthetic fiber base composed of resin fibers, polyester resin fibers, polyester resin fibers such as aromatic polyester resin fibers and wholly aromatic polyester resin fibers, polyimide resin fibers, woven or non-woven fabrics mainly composed of fluororesin fibers, etc. Examples thereof include organic fiber base materials such as paper base materials mainly composed of wood, kraft paper, cotton linter paper, mixed paper of linter and kraft pulp. 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. Moreover, 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, and H glass are mentioned.

  As a method for producing a prepreg for a structural material, generally known methods can be appropriately applied and are not particularly limited. For example, a resin varnish is prepared using the curable resin composition described above, a method of immersing the substrate in the resin varnish, a method of applying the resin varnish to the substrate with various coaters, a method of spraying by spraying, etc. A prepreg can be produced. 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 an inorganic and / or organic fiber base material with a resin composition varnish, drying and forming a B-stage can be applied.

  The fiber-reinforced composite material of the present invention includes the curable resin composition, and can be manufactured using the curable resin composition and the reinforcing fibers. Examples of the reinforcing fiber contained in the fiber-reinforced composite material include carbon fibers, glass fibers, aramid fibers, boron fibers, PBO fibers, high-strength polyethylene fibers, alumina fibers, and silicon carbide fibers. 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. Can be applied to various applications. Therefore, the resin transfer molding method is preferably used when mass-producing a composite material having a relatively complicated shape in a short time.

  The adhesive of this invention contains the said curable resin composition, and can be manufactured using the curable resin composition. As a method for producing the adhesive, generally known methods can be appropriately applied, and are not particularly limited. For example, an adhesive is produced by mixing the curable resin composition and various additives or solvents known to be used in producing an adhesive using a known mixer. be able to. In addition, the addition method of curable resin composition, various additives, and a solvent in the case of mixing can apply a generally well-known thing suitably, and is not specifically limited.

  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, etc. 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 Mw 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 Mw was determined using polystyrene as a standard substance by the GPC method.

(Example 1) Synthesis of cyanate ester compound of furan ring-containing phenol novolak resin (hereinafter abbreviated as FPRCN) FPRCN represented by the following formula (1) was synthesized as described below.
(In formula (1), n represents an integer of 1 to 20)

<Synthesis of furan ring-containing phenol novolak resin (hereinafter abbreviated as “FPROH”)>
First, FPROH represented by the following formula (2) was synthesized.
(In formula (1), n represents an integer of 1 to 20)

  Specifically, 113 g of phenol, 28 g of methanol, and 12 g of sodium hydroxide were charged, stirred and dissolved, and then heated to a reflux state, and 29 g of furfural was added dropwise over 2 hours. Then, after making it react at reflux temperature (90-100 degreeC) for 20 hours, it neutralized with 30g of 35% hydrochloric acid aqueous solution, and 5g of 80% hydrazine aqueous solution was added. Next, 150 g of methyl isobutyl ketone was added and washing with water was repeated, and then unreacted phenol and methyl isobutyl ketone were distilled off under heating and reduced pressure to obtain 332 g of FPROH. The obtained FPROH had an OH group equivalent of 139 g / eq. Met.

<Synthesis of FPCN>
Next, 20 g of FPROH obtained by the above method (OH group equivalent: 139 g / eq.) (0.14 mol in terms of OH group) (weight average molecular weight Mw500: GPC chart is shown in FIG. 1) and 7.3 g of triethylamine (0.07 mol) ) (0.5 mol with respect to 1 mol of hydroxy group) was dissolved in 182 g of dichloromethane.
13.3 g (0.22 mol) of cyanogen chloride (1.5 mol with respect to 1 mol of hydroxy group), 31.0 g of dichloromethane, 32.8 g (0.32 mol) of 36% hydrochloric acid (2. 25 mol) and 163.9 g of water were poured over 30 minutes while stirring at a liquid temperature of −2 to −0.5 ° C. After the completion of 1 solution drop, the mixture was stirred at the same temperature for 30 minutes, and then a solution in which 14.6 g (0.14 mol) of triethylamine (1.0 mol per 1 mol of hydroxy group) was dissolved in 14.6 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 with 100 mL of 0.1N hydrochloric acid and then washed 7 times with 100 g of water. The electric conductivity of the waste water in the seventh 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 21.2 g of the intended cyanate ester compound FPRCN (black purple viscous product). The obtained cyanate ester compound FPRCN had a weight average molecular weight Mw of 930. A GPC chart is shown in FIG. Further, the IR spectrum of FPCN showed absorption at 2236 cm ⁻¹ and 2264 cm ⁻¹ (cyanate ester group) and did not show absorption of a hydroxy group. An IR chart is shown in FIG. FPCN could be dissolved in methyl ethyl ethyl ketone at 50 ° C. or more at 25 ° C.

(Synthesis Example 1) Synthesis of 1,1-bis (4-cyanatophenyl) ethane (hereinafter abbreviated as E-CN) 1,1-bis (4-hydroxyphenyl) ethane (manufactured by Tokyo Chemical Industry Co., Ltd.) ) 300 g (2.80 mol in terms of OH group) and 283.4 g (2.80 mol) of triethylamine (1.0 mol with respect to 1 mol of hydroxy group) were dissolved in 1800 g of dichloromethane.
275.4 g (4.48 mol) of cyanogen chloride (1.6 mol with respect to 1 mol of hydroxy groups), 642.6 g of dichloromethane, 425.4 g (4.20 mol) of 36% hydrochloric acid (1. 5 mol) and 2637.6 g of water were poured over 60 minutes while stirring at a liquid temperature of −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 a solution in which 283.4 g (2.80 mol) of triethylamine (1.0 mol with respect to 1 mol of hydroxy group) was dissolved in 283.4 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 organic phase obtained was washed 5 times with 1300 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 360 g of the intended cyanate ester compound E-CN. The structure of the obtained cyanate ester compound E-CN was identified by NMR. ^{The 1} H-NMR spectrum is shown in FIG.
¹ H-NMR: (270 MHz, chloroform-d, internal standard TMS)
δ (ppm) = 1.62 (d, 3H), 4.22 (q, 1H), 7.42 (complex, 8H)

(Example 2)
<Preparation of curable resin composition and creation of cured product>
100 parts by mass of the cyanate ester compound FPRCN obtained in Example 1 was put into an eggplant type flask, heated and melted at 150 ° C., degassed with a vacuum pump, and then poured into a mold described in JIS-K7238-2-2009. Then, it was cured by heating at 180 ° C. for 3 hours and then at 250 ° C. for 3 hours to obtain a cured product having a side of 100 mm and a thickness of 2 mm.

(Comparative Example 1)
In Example 2, instead of using 100 parts by mass of FPRCN, 100 parts by mass of 2,2-bis (4-cyanatophenyl) propane (trade name of Mitsubishi Gas Chemical Co., Ltd., abbreviated as skylex, TA) was used. A cured product was obtained in the same manner as in Example 1. In addition, 2,2-bis (4-cyanatophenyl) propane skylex could be dissolved in methyl ethyl ketone at 50% by mass or more at 25 ° C.

(Example 3)
20 parts by mass of the cyanate ester compound FPRCN obtained in Example 1, 60 parts by mass of the cyanate ester compound E-CN obtained in Synthesis Example 1, and bis (3-ethyl-5-methyl-4-maleimidophenyl) methane 10 parts by mass (manufactured by Tokyo Chemical Industry Co., Ltd., abbreviated as BMI) and 10 parts by mass of 2,2-bis (3-allyl-4-hydroxyphenyl) propane (manufactured by Wako Pure Chemical Industries, Ltd., abbreviated as DABPA) Put into a separable flask, heat melt at 150 ° C. under reduced pressure with a vacuum pump, stir and mix, then pour into the mold described in JIS-K7238-2-2009, put in an oven, at 180 ° C. for 3 hours, then And cured by heating at 250 ° C. for 5 hours to obtain a cured product having a side of 100 mm and a thickness of 2 mm.

(Comparative Example 2)
In Example 3, instead of using 20 parts by mass of FPRCN, a cured product was obtained in the same manner as in Example 2 except that 20 parts by mass of TA (trade name skylex manufactured by Mitsubishi Gas Chemical) was used.

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 (JIS C6481), using a dynamic viscoelasticity measuring device (model number “AR2000” manufactured by TA Instruments Japan Co., Ltd.), starting temperature 30 Measure the dynamic viscoelasticity of the cured product under the conditions of ℃, end temperature of 400 ℃, heating rate of 3 ℃ / min, measurement frequency of 1 Hz, and the maximum value of the loss elastic modulus (E ″) obtained at that time Glass transition temperature is used as an index of heat resistance.
Thermal expansion coefficient: In accordance with JIS-K-7197-2012 (JIS C6481), using a thermomechanical analyzer (trade name “TMA / SS7100” manufactured by SII NanoTechnology Co., Ltd.), a cured specimen 5 mm × 5mm × 2mm, start temperature 30 ° C, end temperature 330 ° C, rate of temperature increase 10 ° C / min, weight 0.05N (49mN), thermomechanical analysis in expansion / compression mode was performed, at 60-120 ° C The average amount of thermal expansion per 1 ° C. was measured.
Mass reduction rate (%): In accordance with JIS-K7120-1987, using a differential thermal and thermal mass measuring device (trade name “Thermo Plus Evo TG8120” manufactured by Rigaku Corporation), test piece 3 mm × 3 mm × 2 mm, start temperature The mass was measured at 40 ° C., an end temperature of 500 ° C., a temperature increase rate of 10 ° C./min, and a nitrogen atmosphere, and the mass reduction rate at 500 ° C. was calculated based on the following equation.
Mass reduction rate (%) = (DE) / D × 100
D represents the mass at the starting temperature, and E represents the mass at 500 ° C.
Here, the flame retardancy in the present invention is defined as a large amount of residue during pyrolysis, that is, a low mass 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, it was confirmed that the cyanate ester compound of the furan ring-containing phenol novolak resin of the present invention has excellent solvent solubility and excellent handleability. Further, the cured product of the curable resin composition using the cyanate ester compound of the present invention has a low coefficient of thermal expansion, excellent flame retardancy, and a product obtained by using a conventional cyanate ester compound. It was confirmed to have heat resistance.

Claims (10)

A curable resin composition comprising Cie Ann acid ester compound having a structure represented by the following general formula (1),
Structural material for prepreg, sealing materials, fiber-reinforced composite material, or used in adhesives, curable resin composition.
(In the formula, n represents an integer of 1 or more.)   The curable resin composition according to claim 1, wherein the cyanate ester compound is obtained by cyanating a furan ring-containing phenol novolac resin.   The curable resin composition according to claim 2, wherein the furan ring-containing phenol novolak resin is obtained by reacting furfural with phenol in the presence of a basic catalyst.   The curable resin composition as described in any one of Claims 1-3 whose weight average molecular weight Mw of the said cyanate ester compound is 100-3500.   Further comprising at least one selected from the group consisting of a cyanate ester compound other than the cyanate ester compound, a maleimide compound, a phenol resin, an epoxy resin, an oxetane resin, and a compound having a polymerizable unsaturated group, Item 5. The curable resin composition according to any one of Items 1 to 4.   Hardened | cured material formed by hardening the curable resin composition of any one of Claims 1-5.   A prepreg for a structural material, which is obtained by impregnating or coating a curable resin composition according to any one of claims 1 to 5 on a substrate and drying the substrate.   The sealing material containing the curable resin composition of any one of Claims 1-5.   The fiber reinforced composite material containing the curable resin composition of any one of Claims 1-5.   The adhesive agent containing the curable resin composition of any one of Claims 1-5.