Cyanate ester compounds and methods for their production, resin composites, and cured products.

Abstract

Invention details;

Description

Cyanate ester compound, method for producing the same, resin composition, and cured product

[0001] The present invention relates to a cyanate ester compound, a method for producing the same, a resin composition, and a cured product thereof.

[0002] Cyanate ester compounds are known as thermosetting resins that form triazine rings upon curing. Cured products obtained from cyanate ester compounds have properties such as a high glass transition temperature, low dielectric constant and dielectric dissipation factor, and excellent electrical insulation and flame retardancy. Cyanate ester compounds have been widely used as raw materials for various functional polymer materials, such as structural composites, adhesives, electrical insulating materials, and electrical and electronic components.

[0003] Therefore, efforts are being made to develop cyanate esters with better properties and methods for producing them (for example, Patent Documents 1 and 2).

[0004] JP 2005-264154 A

[0005] However, with the cyanate ester compounds described in Patent Documents 1 and 2, it is difficult to control the polymerization reaction during the production of a cured product, and it is difficult to obtain a cured product having desired properties.

[0006] The present invention has been made in view of the above problems, and aims to provide a cyanate ester compound that is easy to control the polymerization reaction during production of a cured product and that is suitable for use in producing a cured product having desired properties, a method for producing the same, a resin composition, and a cured product.

[0007] The present inventors have conducted extensive research to solve the above-mentioned problems, and as a result have found that the above-mentioned problems can be solved by using a specific cyanate ester compound, thereby completing the present invention.

[0008] That is, the present invention is as follows.

[0009] [1] A cyanate ester compound having two or more cyanato groups in the molecule, wherein the content of a compound having a triazine ring is 4.0 area % or less in terms of HPLC area percentage.

[0010] [2] The cyanate ester compound according to [1], wherein the cyanate ester compound is a compound represented by the following formula (1) or a compound represented by the following formula (2):

[0011]

[0012] (In formula (1), Ar １ each independently represents an aromatic ring; each Ra independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms; １ b represents the number of cyanato groups bonded to Ar, each independently being an integer of 1 to 3; １ each independently represents the number of bonds of Ra to Ar １ represents the number obtained by subtracting (a+2) from the number of substitutable groups in the formula (1), c is an integer of 1 to 50, and each X independently represents a single bond, a divalent organic group having 1 to 50 carbon atoms in which a hydrogen atom may be substituted with a heteroatom, a divalent organic group having 1 to 10 nitrogen atoms, a carbonyl group, a carboxy group, a carbonyl dioxide group, a sulfonyl group, a divalent sulfur atom, or a divalent oxygen atom).

[0013]

[0014] (In formula (2), Ar ２ represents an aromatic ring; each Rb independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms; d represents an Ar ２ represents the number of cyanato groups bonded to Ar, and is an integer of 2 or more and 3 or less; ２ indicates the number of bonds of Rb to Ar ２ This indicates the number of substitutable bases minus (d+2).

[0015] [3] In the formula (1), each X is independently represented by the following formula (3):

[0016]

[0017] (In formula (3), Ar３ each independently represent an aromatic ring; Rc, Rd, Rg, and Rh each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms; Re and Rf each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms; and f represents an integer of 0 to 5.

[0018]

[0019] (In formula (4), Ar ４ each independently represent an aromatic ring, Ri and Rj each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and g represents an integer of 0 to 5, and a divalent organic group having 1 to 50 carbon atoms represented by the following formulas (5) to (14):

[0020]

[0021] (in formula (8), h represents an integer of 4 or more and 7 or less, and in formula (13), each Rk independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms).

[0022] [4] The cyanate ester compound according to any one of [1] to [3], wherein the cyanate ester compound is a compound represented by the following formula (15) or a compound represented by the following formula (16):

[0023]

[0024] (In formula (15), Ar ５ each independently represents an aromatic ring; each Rl independently represents a methylene group, a methyleneoxy group, a methyleneoxymethylene group, an oxymethylene group, or a group in which two or more of these are linked together; each Rm and Rn 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 alkoxy group having 1 to 4 carbon atoms; i represents an Ar ５j represents the number of cyanato groups bonded to Ar, each of which is independently an integer of 1 to 3, ５ indicates the number of bonds of Rm to Ar ５ k is the number obtained by subtracting (i+2) from the number of substitutable groups of Ar ５ indicates the number of bonds of Rn to Ar ５ 1 represents an integer of 1 or more, m represents an integer of 1 or more, and the arrangement of each repeating unit is arbitrary.

[0025]

[0026] (In formula (16), Ar ６ each independently represents an aromatic ring; each Ro independently represents a methylene group, a methyleneoxy group, a methyleneoxymethylene group, an oxymethylene group, or a group in which two or more of these are linked together; each Rp and Rq 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 alkoxy group having 1 to 4 carbon atoms; n is a substituted or unsubstituted alkyl group; ６ represents the number of cyanato groups bonded to Ar, and is an integer of 2 or more and 3 or less; ６ indicates the number of bonds of Rp to Ar ６ p represents the number of substitutable groups of Ar ６ represents the number of bonds of Rq to Ar ６ represents a number obtained by subtracting 2 from the number of substitutable groups, and i represents an integer of 1 or more.

[0027] [5] The cyanate ester compound according to any one of [1] to [4], wherein the cyanate ester compound is a compound represented by the following formula (17):

[0028]

[0029] (In formula (17), n represents an integer of 1 or more and 50 or less).

[0030] [6] The cyanate ester compound according to any one of [1] to [5], wherein the compound having a triazine ring is a compound having a structure represented by the following formula (18):

[0031]

[0032] (In formula (18), * indicates a binding site.)

[0033] [7] A method for producing a cyanate ester compound according to any one of [1] to [6], comprising: a raw material solution preparation step of preparing a first solution containing a hydroxy-substituted aromatic compound, a basic compound, and an organic solvent in a vessel while flowing an inert gas through the vessel at a rate of 0.1 L / hour to 20 L / hour per 1 L; and a cyanation step of contacting and reacting the first solution with a second solution containing a cyanogen halide, a hydrogen halide, an organic solvent, and water to cyanate the first solution, thereby obtaining a reaction solution containing the cyanate ester compound.

[0034] [8] The method for producing a cyanate ester compound according to [7], wherein in the raw material solution preparation step, the temperature of the first solution is 5.0°C or less.

[0035] [9] The method for producing a cyanate ester compound according to [7] or [8], wherein in the cyanation step, after the first solution and the second solution are brought into contact with each other to obtain a reaction liquid, a third solution containing a basic compound and an organic solvent is added to the reaction liquid.

[0036]

[10] The method for producing a cyanate ester compound according to any one of [7] to [9], wherein in the cyanation step, the amount of the cyanogen halide used as a raw material is 0.5 mol or more and 5.0 mol or less per 1 mol of hydroxy groups of the hydroxy-substituted aromatic compound.

[0037]

[11] The method for producing a cyanate ester compound according to [7], wherein the temperature of the reaction solution in the cyanation step is 5.0°C or less.

[0038]

[12] A resin composition comprising the cyanate ester compound according to any one of [1] to [6].

[0039]

[13] A cured product obtained by curing the resin composition according to

[12] .

[0040] According to the present invention, it is possible to provide a cyanate ester compound that is easy to control the polymerization reaction during production of a cured product and that is suitable for use in producing a cured product having desired properties, a method for producing the same, a resin composition, and a cured product.

[0041] Hereinafter, a mode for carrying out the present invention (hereinafter referred to as "the present embodiment") will be described in detail. The following present embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content. The present invention can be carried out by appropriately modifying it within the scope of its gist.

[0042] In this embodiment, unless otherwise specified, "resin solid content" or "resin solid content in a resin composition" refers to the resin components in a resin composition excluding fillers, additives (silane coupling agents, wetting and dispersing agents, curing accelerators, and other components), and solvents. "100 parts by mass of resin solid content" or "100 parts by mass of the total resin solid content in a resin composition" refers to 100 parts by mass of the total resin components in a resin composition excluding fillers, additives (silane coupling agents, wetting and dispersing agents, curing accelerators, and other components), and solvents.

[0043] In this specification, the substituent is not particularly limited, and examples thereof include halogen atoms such as fluorine atom, chlorine atom, bromine atom, and iodine atom, hydroxy group, cyano group, nitro group, thiol group, heterocyclic group, linear aliphatic hydrocarbon group, branched aliphatic hydrocarbon group, cyclic aliphatic hydrocarbon group, aryl group, aralkyl group, alkoxy group, alkenyl group, acyl group, alkoxycarbonyl group, alkyloyloxy group, aryloyloxy group, and alkylsilyl group. Specific examples of these substituents may be found by referring to the examples of groups described in this specification.

[0044] [Cyanate Ester Compound] The cyanate ester compound of the present embodiment is a cyanate ester compound having two or more cyanato groups in the molecule, and the content of a compound having a triazine ring is 4.0 area % or less in terms of HPLC area percentage.

[0045] According to this embodiment, it is possible to provide a cyanate ester compound that is easy to control the polymerization reaction during production of a cured product and is suitable for use in producing a cured product having desired properties, and a resin composition containing the cyanate ester compound. By using the cyanate ester compound and resin composition of this embodiment, it is possible to suitably control the polymerization reaction during curing, making it easy to produce a cured product having properties suitable for the desired application. Although the reason for this is unclear, the inventors speculate as follows.

[0046] That is, although a compound having a triazine ring promotes polymerization of a cyanate ester compound, the content of the compound having a triazine ring in the cyanate ester compound of this embodiment is suitably controlled to be 4.0 area % or less in terms of HPLC area percentage, thereby enabling suitably controlling the polymerization reaction during production of a cured product.

[0047] Therefore, the present inventors have presumed that the present embodiment can provide a cyanate ester compound that is easily controlled in the polymerization reaction during production of a cured product and that is suitable for use in producing a cured product having desired properties, and a resin composition containing the cyanate ester compound. However, the reason is not limited to this. The cyanate ester compound of the present embodiment can be suitably obtained, for example, by using the production method described below.

[0048] Since the polymerization reaction during production of a cured product can be more easily controlled and a cyanate ester compound that is more suitable for use in producing a cured product having desired properties can be obtained, the content of the compound having a triazine ring is preferably 3.0 area % or less, more preferably 2.0 area % or less, and even more preferably 1.5 area % or less, in terms of HPLC area percentage. The lower limit is not particularly limited, but is usually 0.5 area % or more, taking into account the lower limit of HPLC quantitation.

[0049] The content of the compound having a triazine ring is measured using high-performance liquid chromatography (HPLC). Examples of such a measurement method include a method for measuring the content under the following conditions; for specific measurement methods, see the description in the Examples. Specifically, 2.0 g of the resulting 2-butanone solution containing 50% by mass of the cyanate ester compound is dissolved in 50 g of tetrahydrofuran (solvent) to obtain a solution. 2.0 μL of this solution is injected into a high-performance liquid chromatograph for analysis. Measurement conditions include, for example, a TSKgel ODS-120T (length 25 cm × inner diameter 4.6 mm) column manufactured by Tosoh Corporation, acetonitrile / water (80 / 20 volume ratio) as the mobile phase, a flow rate of 1.0 mL / min, a detection wavelength of 274 nm, and a column temperature of 35°C. For example, when the cyanate ester compound is a compound represented by formula (17), under those conditions, a peak observed at a retention time (RT) of 1.5 minutes is considered to be a peak derived from the compound having a triazine ring represented by formula (18), and the content of the compound having a triazine ring in the cyanate ester compound is calculated from the peak area value.

[0050] Examples of compounds having a triazine ring include compounds having a group represented by the following formula (19).

[0051]

[0052] In formula (19), "-*" indicates a binding site.

[0053] The bonding sites are each independently bonded to an organic group or a hydrogen atom. That is, the compound having a triazine ring of this embodiment also includes triazines. Examples of organic groups include groups containing one or more carbon atoms, or groups formed by removing one hydrogen atom from an organic compound. Examples of such organic groups include amino groups, alkyl groups, cycloalkyl groups, alkoxy groups, aryl groups, aralkyl groups, alkylcarbonyl groups, alkoxycarbonyl groups, and alkylcarbonyloxy groups. These groups may have an ether bond or a carbonyl group.

[0054] In the compound having a triazine ring, when the bonding site in formula (19) is bonded to the organic group via an ether bond, the content of the compound having a triazine ring is preferably within the above range. By having the content of such a compound within the above range, it becomes easier to control the polymerization reaction during production of a cured product, and a cyanate ester compound that is more suitable for producing a cured product having desired properties tends to be obtained.

[0055] It is more preferable that the content of the compound represented by the following formula (18) as the compound having a triazine ring is in the above range, because this makes it easier to control the polymerization reaction during production of a cured product and allows for the production of a cyanate ester compound that is more suitably used for producing a cured product having desired properties.

[0056]

[0057] In formula (18), "-*" indicates a binding site.

[0058] In this embodiment, the compound having a triazine ring is a by-product generated when the cyanation of a hydroxy-substituted aromatic compound proceeds excessively in the presence of a basic compound. Therefore, the compound having a triazine ring has a triazine ring generated by cyclization of a cyanato group in the presence of a basic compound. The bonding site bonds to the cyanate ester compound. For example, in a cyanate ester compound having a structure in which the cyanato group is bonded to an aromatic ring, the bonding site bonds to the aromatic ring in the cyanate ester compound. That is, the oxygen atom in "-*-O" in formula (18) is the oxygen atom in the cyanato group.

[0059] The cyanate ester compound is preferably a compound represented by the following formula (1) or a compound represented by the following formula (2), and more preferably a compound represented by formula (1), because it makes it easier to control the polymerization reaction during production of a cured product and provides a cyanate ester compound that is more suitably used for producing a cured product having desired properties.

[0060] (Compound Represented by Formula (1)) The compound represented by formula (1) is shown below.

[0061]

[0062] In formula (1), Ar １ each independently represents an aromatic ring; each Ra independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms; １ b represents the number of cyanato groups bonded to Ar, each independently being an integer of 1 to 3; １ each independently represents the number of bonds of Ra to Ar １ represents the number obtained by subtracting (a+2) from the number of substitutable groups in formula (1), c is an integer of 1 to 50, and each X independently represents a single bond, a divalent organic group having 1 to 50 carbon atoms in which a hydrogen atom may be substituted with a hetero atom, a divalent organic group having 1 to 10 nitrogen atoms, a carbonyl group, a carboxy group, a carbonyl dioxide group, a sulfonyl group, a divalent sulfur atom, or a divalent oxygen atom. Each group in formula (1) may have a substituent.

[0063] In formula (1), Ar １ Each independently represents an aromatic ring. １ Examples of the aromatic ring represented by Ar include a phenyl group and a naphthyl group. Since the polymerization reaction during the production of a cured product can be more easily controlled and a cyanate ester compound that is more suitably used for the production of a cured product having desired properties can be obtained, １ is preferably a phenyl group.

[0064] Each Ra independently represents a hydrogen atom, an alkyl group having from 1 to 6 carbon atoms, an alkenyl group having from 2 to 6 carbon atoms, an aryl group having from 6 to 12 carbon atoms, or an alkoxy group having from 1 to 4 carbon atoms. Ra is preferably a hydrogen atom or an alkenyl group having from 2 to 6 carbon atoms, since this makes it easier to control the polymerization reaction during production of a cured product and results in a cyanate ester compound that is more suitably used for producing a cured product having desired properties.

[0065] Examples of alkyl groups having 1 to 6 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, neopentyl, n-hexyl, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl. The alkyl group may be linear, branched, or cyclic.

[0066] Examples of alkenyl groups having 2 to 6 carbon atoms include vinyl, allyl, butenyl, pentenyl, and hexenyl groups. Among alkenyl groups having 2 to 6 carbon atoms, alkenyl groups having 2 to 5 carbon atoms are preferred, as this allows for easier control of the polymerization reaction during production of a cured product, and results in a cyanate ester compound that is more suitable for use in producing a cured product having desired properties. The alkenyl group may be linear, branched, or cyclic.

[0067] Examples of the aryl group having 6 to 20 carbon atoms include a phenyl group and a naphthyl group.

[0068] Examples of the alkoxy group having 1 to 4 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. The alkoxy group may be linear, branched, or cyclic.

[0069] a is Ar １ a represents the number of cyanate groups bonded to the compound, and each independently represents an integer of 1 or more and 3 or less. a is preferably an integer of 1 or more and 2 or less, and more preferably 1, because this makes it easier to control the polymerization reaction during production of a cured product and allows for the production of a cyanate ester compound that is more suitably used for producing a cured product having desired properties.

[0070] b is Ar １ each independently represents the number of bonds of Ra to Ar １ This represents the number obtained by subtracting (a+2) from the number of substitutable bases.

[0071] c is an integer of 1 or more and 50 or less. c is preferably an integer of 1 or more and 10 or less, more preferably an integer of 1 or more and 5 or less, and even more preferably 1, because this makes it easier to control the polymerization reaction during production of a cured product and allows for the production of a cyanate ester compound that is more suitably used for producing a cured product having desired properties to be obtained.

[0072] Each X independently represents a single bond, a divalent organic group having from 1 to 50 carbon atoms in which a hydrogen atom may be substituted with a hetero atom, a divalent organic group having from 1 to 10 nitrogen atoms (-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 -), a divalent sulfur atom, or a divalent oxygen atom.

[0073] Examples of the divalent organic group having 1 to 50 carbon atoms in which a hydrogen atom may be substituted with a heteroatom include linking groups selected from the group consisting of divalent groups represented by formulas (3) to (14).

[0074] In order to more easily control the polymerization reaction during production of a cured product and obtain a cyanate ester compound that is more suitably used for producing a cured product having desired properties, X in the compound represented by formula (1) is preferably a cyanate ester compound represented by formula (3):

[0075]

[0076] (In formula (3), Ar ３ each independently represent an aromatic ring; Rc, Rd, Rg, and Rh each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms; Re and Rf each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms; and f represents an integer of 0 to 5.

[0077]

[0078] (In formula (4), Ar ４each independently represent an aromatic ring, Ri and Rj each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and g represents an integer of 0 to 5, and a divalent organic group having 1 to 50 carbon atoms represented by the following formulas (5) to (14):

[0079]

[0080] (in formula (8), h represents an integer of 4 or more and 7 or less, and in formula (13), each Rk independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms).

[0081] In formulas (3) and (4), Ar ３ and Ar ４ As the aromatic ring represented by the formula: Ar １ In formulas (3) and (4), examples of the alkyl group having 1 to 6 carbon atoms or the aryl group having 6 to 12 carbon atoms represented by Rc, Rd, Rg, and Rh, and the alkyl group having 1 to 6 carbon atoms, the aryl group having 6 to 12 carbon atoms, and the alkoxy group having 1 to 4 carbon atoms represented by Re, Rf, Ri, and Rj include the same as those exemplified for Ra. Each group in formulas (3) and (4) may have a substituent.

[0082] Examples of the compound represented by formula (1) include bisphenol A cyanate, bisphenol E cyanate, and diallyl bisphenol A cyanate.

[0083] As the compound represented by formula (1), a compound represented by the following formula (15) is preferred, since it allows easier control of the polymerization reaction during production of a cured product and is more suitably used for producing a cured product having desired properties.

[0084]

[0085] In formula (15), Ar ５each independently represents an aromatic ring; each Rl independently represents a methylene group, a methyleneoxy group, a methyleneoxymethylene group, an oxymethylene group, or a group in which two or more of these are linked together; each Rm and Rn 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 alkoxy group having 1 to 4 carbon atoms; i represents an Ar ５ j represents the number of cyanato groups bonded to Ar, each of which is independently an integer of 1 to 3, ５ indicates the number of bonds of Rm to Ar ５ k is the number obtained by subtracting (i+2) from the number of substitutable groups of Ar ５ indicates the number of bonds of Rn to Ar ５ where 1 is an integer of 1 or more, m is an integer of 1 or more, and the arrangement of the repeating units is arbitrary. Each group in formula (15) may have a substituent.

[0086] In formula (15), Ar ５ As the aromatic ring represented by the formula: Ar １ In formula (15), examples of the alkyl group having 1 to 6 carbon atoms, the aryl group having 6 to 12 carbon atoms, and the alkoxy group having 1 to 4 carbon atoms represented by Rm and Rn include the same as those exemplified for Ra. l represents an integer of 1 or more, preferably an integer of 1 to 10, and more preferably an integer of 1 to 5. m represents an integer of 1 or more, preferably an integer of 1 to 10, and more preferably an integer of 1 to 5.

[0087] (Compound Represented by Formula (2)) The compound represented by formula (2) is shown below.

[0088]

[0089] In formula (2), Ar ２ represents an aromatic ring; each Rb independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms; d represents an Ar ２represents the number of cyanato groups bonded to Ar, and is an integer of 2 or more and 3 or less; ２ indicates the number of bonds of Rb to Ar ２ The number of groups in formula (2) is calculated by subtracting (d+2) from the number of substitutable groups. Each group in formula (2) may have a substituent.

[0090] In formula (2), Ar ２ As the aromatic ring represented by the formula: Ar １ In formula (2), examples of the alkenyl group having from 2 to 6 carbon atoms, the aryl group having from 6 to 12 carbon atoms, and the alkoxy group having from 1 to 4 carbon atoms, represented by Rb, include the same groups as those exemplified for Ra.

[0091] The cyanate ester compound of the present embodiment is preferably a compound represented by the following formula (16).

[0092]

[0093] In formula (16), Ar ６ each independently represents an aromatic ring; each Ro independently represents a methylene group, a methyleneoxy group, a methyleneoxymethylene group, an oxymethylene group, or a group in which two or more of these are linked together; each Rp and Rq 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 alkoxy group having 1 to 4 carbon atoms; n is a substituted or unsubstituted alkyl group; ６ represents the number of cyanato groups bonded to Ar, and is an integer of 2 or more and 3 or less; ６ indicates the number of bonds of Rp to Ar ６ p represents the number of substitutable groups of Ar ６ represents the number of bonds of Rq to Ar ６ and i represents an integer of 1 or greater. Each group in formula (16) may have a substituent.

[0094] In formula (16), Ar ６ As the aromatic ring represented by the formula: Ar １In formula (16), examples of the alkyl group having 1 to 6 carbon atoms, the aryl group having 6 to 12 carbon atoms, and the alkoxy group having 1 to 4 carbon atoms, represented by Rp and Rq, include the same as those exemplified for Ra. i represents an integer of 1 or more, preferably an integer of 1 to 10, and more preferably an integer of 1 to 5.

[0095] The compound represented by formula (1) is preferably a compound represented by formula (17) below, since it is easier to control the polymerization reaction during production of a cured product and is more suitable for use in producing a cured product having desired properties.

[0096]

[0097] In formula (17), n represents an integer of 1 or more and 50 or less. n is preferably an integer of 1 or more and 10 or less, since this makes it easier to control the polymerization reaction during production of a cured product, and results in a cyanate ester compound that is even more suitably used for producing a cured product having desired properties.

[0098] [Method for Producing Cyanate Ester Compound] The method for producing a cyanate ester compound of this embodiment includes a raw material solution preparation step of preparing a first solution (hereinafter also referred to as "solution 1") containing a hydroxy-substituted aromatic compound, a basic compound (hereinafter also referred to as "basic compound 1"), and an organic solvent (hereinafter also referred to as "organic solvent 1") in a vessel while flowing an inert gas through the vessel at a rate of 0.1 L / hour to 20 L / hour per 1 L, and a cyanation step (hereinafter also referred to as the "cyanation step") of contacting and reacting the first solution with a second solution (hereinafter also referred to as "solution 2") containing a cyanogen halide, a hydrogen halide, a second organic solvent (hereinafter also referred to as "organic solvent 2"), and water to cyanate the first solution, thereby obtaining a reaction solution containing the cyanate ester compound. Note that organic solvent 2 may be the same as or different from organic solvent 1.

[0099] By undergoing such specific steps, it is possible to preferably produce a cyanate ester compound in which the content of a compound having a triazine ring is 4.0 area % or less in terms of HPLC area percentage, the polymerization reaction during production of a cured product is easily controlled, and the cyanate ester compound is preferably used to produce a cured product having desired properties. Although the reason for this is unclear, the present inventors speculate as follows.

[0100] That is, in the production method of this embodiment, a raw material solution preparation step, prior to the cyanation step, includes preparing Solution 1 containing a hydroxy-substituted aromatic compound, a basic compound 1, and an organic solvent 1 while flowing an inert gas in a container at a rate of 0.1 L / hour to 20 L / hour per 1 L of container. In the hydroxy-substituted aromatic compound obtained through this step, the oxidation reaction in which the hydroxy group converts to a ketone is suitably suppressed. Then, in the cyanation step of the cyanate ester compound, a solution containing a hydroxy-substituted aromatic compound in which oxidation to a ketone is suppressed is used as the raw material solution. Therefore, in the cyanation step, excessive cyanation of the hydroxy-substituted aromatic compound can be suitably suppressed, and the reaction from the hydroxy group in the hydroxy-substituted aromatic compound to a cyanato group can proceed more smoothly. This makes it possible to suitably control the by-production of a compound having a triazine ring.

[0101] Therefore, the present inventors have presumed that the production method of this embodiment can preferably produce a cyanate ester compound in which the content of the compound having a triazine ring is 4.0 area % or less in terms of HPLC area percentage, which makes it easy to control the polymerization reaction during production of a cured product and is suitable for use in producing a cured product having desired properties, although the reasons are not limited to these.

[0102] First, each step in the method for producing a cyanate ester compound will be described, and each component to be supplied to the raw material solution preparation step, the cyanation step, etc. will be described later.

[0103] [Stock Solution Preparation Step] The method for producing a cyanate ester compound of the present embodiment includes a step of preparing Solution 1 containing a hydroxy-substituted aromatic compound, a basic compound 1, and an organic solvent 1 in a container, while flowing an inert gas through the container at a rate of 0.1 L / hour to 20 L / hour per L, to prepare Solution 1. Organic solvent 1 may be the same as or different from organic solvent 2, but it is preferable that they are the same.

[0104] As the container, any known container can be used depending on the properties of the raw material, as long as it can pass an inert gas through it at a rate of 0.1 L / hour to 20 L / hour per 1 L of container. In this embodiment, since the raw material is prepared while passing an inert gas through it, the container is preferably an openable container. Examples of such a container include a container with an openable lid, and a container equipped with a supply pipe and a valve for passing an inert gas through a portion of the container and a vent line (discharge pipe) on the outlet side.

[0105] The container is preferably a container having a function for stirring the solution, such as a stirring blade, a stirrer, a paddle, a ribbon, a screw, and a mixer.

[0106] Examples of materials for the container include glass; metal materials such as stainless steel, nickel, Monel (registered trademark), and Hastelloy (registered trademark); fluorine-based resins such as polytetrafluoroethylene (PTFE); and plastics such as polyethylene terephthalate (PET). The surface or interior of the container may be lined with a resin or the like. Examples of such resins include fluorine-based resins such as polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and tetrafluoroethylene-hexafluoropropylene copolymer (FEP), as well as olefin-based resins such as polypropylene.

[0107] The container is preferably a container containing glass or a container containing stainless steel. When such a container is used, the content of the compound having a triazine ring is within the above range, making it easy to control the polymerization reaction during production of a cured product, and it is possible to preferably produce a cyanate ester compound that is suitable for producing a cured product with desired properties. In addition to the above effects, the container is more preferably a container containing stainless steel from the standpoints of high solvent resistance and low cost.

[0108] Examples of the shape of the container include a spherical shape, a prolate spheroid shape, a horizontal cylindrical shape, an inclined cylindrical shape, a V shape, a conical shape, a cubic shape, and a flask shape.

[0109] Specific examples of the container include glass containers such as flasks, bottles, and vials, and known vessels such as reaction vessels.

[0110] The capacity of the container can be appropriately set depending on the properties of the raw materials, etc., as long as it is a capacity that allows the inert gas to flow at a rate of 0.1 L / hour to 20 L / hour per liter of the container. The capacity of the container is preferably 0.1 L to 30,000 L. By using such a container, the content of the compound having a triazine ring falls within the above range, making it easy to control the polymerization reaction during production of a cured product, and it is possible to preferably produce a cyanate ester compound that is suitable for producing a cured product having desired properties.

[0111] In the raw material solution preparation step, the gas flow rate of the inert gas is preferably 0.2 L / hour to 18 L / hour, more preferably 0.3 L / hour to 17 L / hour, per 1 L of container. In the raw material solution preparation step, the inert gas may be circulated so as to create an inert gas atmosphere inside the container. The inert gas may be circulated so as to contact the upper surface (liquid surface) of the raw material, or the inert gas may be bubbled through the raw material. Furthermore, it is preferable to circulate the inert gas in advance so as to create an inert gas atmosphere inside the container before preparing the raw material container.

[0112] Examples of inert gases include nitrogen, helium, and argon. Nitrogen is preferred as the inert gas. By using nitrogen, the content of the compound having a triazine ring falls within the above range, making it easy to control the polymerization reaction during production of a cured product, and it is possible to preferably produce a cyanate ester compound that is suitable for producing a cured product having desired properties.

[0113] In the raw material solution preparation step, the temperature of solution 1 containing a hydroxy-substituted aromatic compound, basic compound 1, and organic solvent 1 is preferably 5.0° C. or lower, more preferably −20° C. or higher and 3.0° C. or lower, and even more preferably −10° C. or higher and 1.0° C. or lower. When the solution temperature is within the above range, the content of the compound having a triazine ring is within the above range, making it easier to control the polymerization reaction during production of a cured product, and tends to more preferably produce a cyanate ester compound that is suitably used for producing a cured product having desired properties.

[0114] In the raw material solution preparation step, the pressure inside the vessel is not particularly limited as long as it is a pressure that allows a desired solution to be obtained in the raw material solution preparation step.

[0115] In the raw material solution preparation step, the time for flowing the inert gas through the container is preferably 1 minute to 20 hours, more preferably 3 minutes to 10 hours. In this embodiment, the solution obtained in the raw material solution preparation step is used as a raw material in the subsequent cyanation step, so it is preferable to flow the inert gas through the container until then. This tends to ensure that the content of the compound having a triazine ring is within the above range, making it easier to control the polymerization reaction during production of a cured product and more preferably producing a cyanate ester compound that is suitable for producing a cured product with desired properties.

[0116] In the raw material solution preparation step or in preparation of the solution obtained in the raw material solution preparation step, the amount of organic solvent 1 blended is preferably an amount capable of dissolving basic compound 1 and the hydroxy-substituted aromatic compound. The amount of organic solvent 1 blended is usually 50% by mass or more and 90% by mass or less relative to 100% by mass of the solution (raw material).

[0117] In the raw solution preparation step or in preparation of the solution obtained in the raw solution preparation step, the amount of basic compound 1 blended is preferably 0.1 mol or more and 8.0 mol or less, more preferably 0.5 mol or more and 3.0 mol or less, relative to 1 mol of hydroxy groups of the hydroxy-substituted aromatic compound. When the blending ratio of basic compound 1 to the hydroxy-substituted aromatic compound is within the above range, the content of the triazine ring compound is within the above range, making it easier to control the polymerization reaction during production of a cured product, and there is a tendency to more preferably produce a cyanate ester compound that is suitably used for producing a cured product having desired properties.

[0118] [Cyanation Step] The method for producing a cyanate ester compound includes a cyanation step of contacting and reacting Solution 1 with Solution 2 to cyanate, thereby obtaining a reaction liquid containing a cyanate ester compound. Because the cyanation step is such a specific step, the content of the compound having a triazine ring is within the above range, making it easy to control the polymerization reaction during production of a cured product, and making it possible to more preferably produce a cyanate ester compound that is suitably used for producing a cured product having desired properties.

[0119] Examples of a method for contacting and reacting Solution 1 and Solution 2 include a method in which the cyanogen halide contained in Solution 2 and the hydroxy-substituted aromatic compound contained in Solution 1 are stirred in the presence of the basic compound contained in Solution 1 to bring the two components into contact with each other and cause a reaction.

[0120] In the cyanation step, the contacting of Solution 1 with Solution 2 can be carried out in either a semi-batch or continuous flow manner. Specifically, examples of the contacting method include (a) a method of adding Solution 1 dropwise to Solution 2 while stirring and mixing, (b) a method of adding Solution 2 dropwise to Solution 1 while stirring and mixing, and (c) a method of supplying a portion of Solution 2 and a portion of Solution 1 continuously or intermittently, alternately, or simultaneously to a reaction vessel. In these methods, the solution may be added dropwise in appropriate portions. For example, in Method (a), Solution 1 may be added dropwise in portions to Solution 2 while stirring and mixing. The number of separate additions is typically, for example, 2 to 5 times.

[0121] Among methods (a) to (c), method (a) is preferred. When method (a) is used as the contacting operation method, the content of the compound having a triazine ring is within the above range, making it easy to control the polymerization reaction during production of a cured product, and it is possible to more preferably produce a cyanate ester compound that is suitably used for producing a cured product having desired properties.

[0122] In the cyanation step, the reaction time is not particularly limited, but the dropwise addition time in the contacting operation of method (a) and method (b), and the contact time in the contacting operation of method (c) are preferably 1 minute to 20 hours, more preferably 3 minutes to 10 hours. Furthermore, it is preferable to subsequently stir the mixture for 10 minutes to 10 hours while maintaining the reaction temperature. By keeping the reaction time within the above range, the target cyanate ester compound tends to be obtained more efficiently, economically and industrially. The stirring method may be as described above.

[0123] Examples of the stirring method include a method using a known stirrer such as a stirring blade, a stirrer, a paddle, a ribbon, a screw, a mixer, etc. The stirring time may be determined by referring to the reaction time described above, and is preferably 1 minute to 20 hours, more preferably 3 minutes to 10 hours.

[0124] In the cyanation step, the temperature of the reaction liquid is preferably 5.0° C. or lower, more preferably −20° C. or higher and 3.0° C. or lower, and even more preferably −10° C. or higher and 2.0° C. or lower. When the temperature of the reaction liquid is within the above range, the content of the compound having a triazine ring is within the above range, which makes it easier to control the polymerization reaction during production of a cured product, and tends to more preferably produce a cyanate ester compound that is suitably used for producing a cured product having desired properties.

[0125] In the cyanation step, the pressure inside the vessel is not particularly limited as long as a reaction liquid containing the desired cyanate ester compound is obtained. If necessary, an inert gas such as nitrogen, helium, or argon may be passed through the reaction system.

[0126] In the solution 1 used in the cyanation step, the content of the organic solvent 1 is preferably an amount capable of dissolving the basic compound and the hydroxy-substituted aromatic compound. The content of the organic solvent 1 is usually 50% by mass or more and 90% by mass or less relative to 100% by mass of the solution 1.

[0127] In solution 1 used in the cyanation step, the content of basic compound 1 is preferably 0.1 mol or more and 8.0 mol or less, more preferably 0.5 mol or more and 3.0 mol or less, relative to 1 mol of hydroxy groups in the hydroxy-substituted aromatic compound. When the content ratio of basic compound 1 to hydroxy-substituted aromatic compound is within the above range, the content of the compound having a triazine ring is within the above range, making it easier to control the polymerization reaction during production of a cured product, and tends to more preferably produce a cyanate ester compound that is suitably used for producing a cured product having desired properties.

[0128] In Solution 2, the amounts of cyanogen halide and hydrogen halide may be determined by reference to the amounts of hydrogen halide used and the amount of cyanogen halide charged as raw materials, respectively, as described below. The amount of water used is preferably sufficient to dissolve the hydrogen halide. In Solution 2, the mass ratio of water to organic solvent 2 (water / organic solvent 2) is not particularly limited, but is preferably 1 / 100 to 100 / 1, more preferably 1 / 10 to 10 / 1, and even more preferably 1 / 5 to 5 / 1.

[0129] The cyanation step is more preferably a step of contacting Solution 2 with Solution 1 containing a hydroxy-substituted aromatic compound to cyanate the resulting mixture to obtain a reaction solution containing a cyanate ester compound, and then pouring into the reaction solution a third solution (hereinafter also referred to as "Solution 3") containing a basic compound (hereinafter also referred to as "Basic Compound 2") and an organic solvent (hereinafter also referred to as "Organic Solvent 3"). Note that Basic Compound 2 may be the same as or different from Basic Compound 1, but is preferably the same. Organic Solvent 3 may be the same as Organic Solvent 1, but is preferably the same. Organic Solvent 3 may be the same as Organic Solvent 2, but is preferably the same. Adding Solution 3 to the resulting reaction solution tends to produce a high-purity cyanate ester compound in high yield.

[0130] It is preferable that basic compound 2 and organic solvent 3 contained in solution 3 are the same components as basic compound 1 and organic solvent 1 contained in solution 1. When the cyanation step is such a specific step, the content of the compound having a triazine ring is within the above range, making it easier to control the polymerization reaction during production of a cured product, and making it possible to more preferably produce a cyanate ester compound that is suitably used for producing a cured product having desired properties.

[0131] In Solution 3, the amount of basic compound 2 is preferably 0.05 mol or more and 2.5 mol or less, more preferably 0.1 mol or more and 2.3 mol or less, relative to 1 mol of hydroxy groups in the hydroxy-substituted aromatic compound. When the amount of basic compound 2 used is within the above range, the content of the compound having a triazine ring is within the above range, making it easier to control the polymerization reaction during production of a cured product, and tends to enable more preferable production of a cyanate ester compound suitable for producing a cured product having desired properties in high yield.

[0132] In the solution 3, the organic solvent 3 is preferably used in an amount sufficient to dissolve the basic compound 2. The content of the organic solvent 3 is usually 30% by mass or more and 90% by mass or less relative to 100% by mass of the solution 3.

[0133] The temperature at which Solution 3 is added to the reaction solution may be determined by reference to the temperature of the reaction solution described above. Since a highly pure cyanate ester compound tends to be obtained in high yield, the temperature at which Solution 3 is added to the reaction solution is preferably the same as the temperature of the reaction solution described above.

[0134] The pressure inside the vessel when adding Solution 3 to the reaction mixture is not particularly limited as long as the desired solution can be obtained. If necessary, an inert gas such as nitrogen, helium, or argon may be passed through the system.

[0135] The time for adding Solution 3 to the reaction liquid is preferably 1 minute to 20 hours, more preferably 1.5 minutes to 10 hours. Furthermore, it is preferable to subsequently stir the reaction liquid for 10 minutes to 10 hours while maintaining the same temperature as that at which Solution 3 was added to the reaction liquid. When the time for adding Solution 3 to the reaction liquid is within the above range, the target cyanate ester compound tends to be obtained more efficiently economically and industrially.

[0136] [Other Steps] After the cyanation step or the step of pouring Solution 3 into the reaction solution, the target cyanate ester compound can be isolated by performing a typical post-treatment operation and, if desired, a separation operation and / or purification operation. Specifically, after separating the solution containing an organic phase containing the cyanate ester compound from an aqueous phase, the separated organic phase is heated and distilled to remove the cyanogen halide and the organic solvent. The target cyanate ester compound can then be precipitated or crystallized by adding an organic solvent, washing with water, and concentrating. Alternatively, after washing with water and concentrating, the solvent in the organic phase can be replaced with a solvent in which the cyanate ester compound is insoluble or poorly soluble, thereby precipitating or crystallizing the cyanate ester compound. During washing, an acidic aqueous solution such as dilute hydrochloric acid may be used to remove excess amines. Furthermore, to remove water from the thoroughly washed organic phase, a drying operation can be performed by a common method using sodium sulfate, magnesium sulfate, or the like.

[0137] Furthermore, during concentration and solvent substitution, in order to more suitably suppress polymerization of the cyanate ester compound, it is preferable to distill off the organic solvent under reduced pressure and heating at a temperature of 90°C or less. Precipitation or crystallization can be carried out by adding dropwise a solvent having low solubility for the cyanate ester compound to a solution containing the cyanate ester compound, or by adding dropwise a solution containing the cyanate ester compound to a solvent having low solubility for the cyanate ester compound. Examples of solvents having low solubility for the cyanate ester compound include ether-based solvents; hydrocarbon-based solvents such as hexane; and alcohol-based solvents.

[0138] To wash the obtained crude product, the concentrate of the reaction solution or the precipitated or crystallized crystals may be washed with a solvent having low solubility for the cyanate ester compound. The crystals obtained by concentrating the reaction solution may be redissolved and then recrystallized. When crystallization is desired, the reaction solution may simply be concentrated or cooled.

[0139] The purity of the obtained cyanate ester compound can be analyzed, for example, by liquid chromatography or FT-IR (Fourier transform infrared spectroscopy). By-products such as dialkylcyanoamide and volatile components such as residual solvents in the cyanate ester compound can be quantitatively analyzed by gas chromatography. Halides remaining in the cyanate ester compound can be identified by liquid chromatography-mass spectrometry 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 using a hot plate method or a torque measurement method.

[0140] Next, each component to be subjected to the cyanation step will be described.

[0141] (Hydrogen Halide) In the cyanation step, hydrogen halide is used to adjust the pH and suppress the by-production of impurities.

[0142] In the cyanation step, the pH of the reaction liquid is preferably less than 7.0, more preferably not more than 6.5, and even more preferably not more than 6.0. By carrying out the reaction while maintaining the pH of the reaction liquid at less than 7.0, the content of the compound having a triazine ring is within the above range, making it easier to control the polymerization reaction during production of a cured product, and more preferably producing a cyanate ester compound that is suitably used for producing a cured product having desired properties.

[0143] Examples of methods for adding hydrogen halide include a method in which hydrogen halide is added to Solution 1 before cyanation, and a method in which hydrogen halide is added to Solution 1 while appropriately measuring the pH with a pH meter. In this case, in addition to hydrogen halide, inorganic acids such as nitric acid, sulfuric acid, and phosphoric acid, and organic acids such as acetic acid, lactic acid, and propionic acid may be used.

[0144] Examples of hydrogen halides include hydrogen fluoride, hydrogen chloride, hydrogen bromide, and hydrogen iodide. The hydrogen halide may be an acidic aqueous solution such as hydrofluoric acid or hydrochloric acid. These hydrogen halides can be used alone or in combination of two or more.

[0145] When the content of the compound having a triazine ring is within the above range, the polymerization reaction during production of a cured product can be easily controlled, and a cyanate ester compound that is suitable for producing a cured product with desired properties can be more preferably produced. When the hydrogen halide is hydrochloric acid, its concentration in the reaction solution is preferably, for example, 1.0% or more and 10% or less. Use of hydrochloric acid at such a concentration tends to produce a cyanate ester with high purity.

[0146] The amount of hydrogen halide used is preferably 0.5 mol or more and 5.0 mol or less, more preferably 1.0 mol or more and 3.5 mol or less, relative to 1 mol of hydroxy groups of the hydroxy-substituted aromatic compound. When the amount of hydrogen halide used is within the above range, the content of the compound having a triazine ring is within the above range, making it easier to control the polymerization reaction during production of a cured product, and tends to more preferably produce a cyanate ester compound that is suitably used for producing a cured product having desired properties.

[0147] (Organic Solvent) As the organic solvents 1 to 3, any generally known organic solvent can be used as long as it is immiscible with water and inert to the cyanation reaction. Examples of such organic solvents include halogenated hydrocarbon solvents such as dichloromethane, chloroform, carbon tetrachloride, dichloroethane, trichloroethane, chlorobenzene, and bromobenzene; aliphatic solvents such as n-hexane, cyclohexane, and isooctane; aromatic solvents such as benzene, toluene, xylene, and ethylbenzene; ketone solvents such as methyl ethyl ketone, cyclohexanone, cyclopentanone, and methyl isobutyl ketone; nitrile solvents such as benzonitrile; nitro solvents such as nitrobenzene; ether solvents such as diethyl ether, diisopropyl ether, and tetrahydrofuran; and ester solvents such as ethyl acetate and ethyl benzoate. These organic solvents can be used alone or in combination of two or more. Among these, preferred organic solvents are halogenated hydrocarbon solvents having 1 to 2 carbon atoms, such as dichloromethane, chloroform, carbon tetrachloride, dichloroethane, and trichloroethane.

[0148] In this embodiment, as long as the effects of the present invention are achieved, the organic solvent may be mixed with the organic solvent described above, for example, a solvent miscible with water, etc. Examples of such organic solvents include acetone, dimethyl cellosolve, diglyme, tetraethylene glycol dimethyl ether, methanol, ethanol, isopropanol, methyl cellosolve, propylene glycol monomethyl ether, N,N-dimethylformamide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidone, dimethyl sulfoxide, and acetonitrile.

[0149] (Water) Examples of water include tap water, distilled water, and deionized water. Among these, it is preferable to use distilled water or deionized water with few impurities from the viewpoint of efficiently obtaining the target cyanate ester compound.

[0150] The total amount of solvents used in the cyanation step, i.e., the total amount of organic solvents 1 to 3 and water, is preferably 1.0 part by mass or more and 200 parts by mass or less, more preferably 1.5 parts by mass or more and 150 parts by mass or less, and even more preferably 2.5 parts by mass or more and 100 parts by mass or less, relative to 1 part by mass of the hydroxy-substituted aromatic compound. When the total amount of solvents is within the above range, the hydroxy-substituted aromatic compound can be uniformly dissolved, and the production efficiency of the cyanate ester compound tends to be further improved.

[0151] (Cyanogen Halide) In the cyanation step, a cyanogen halide is used to cyanate the hydroxy-substituted aromatic compound.

[0152] Examples of cyanogen halides include cyanogen fluoride, cyanogen chloride, cyanogen bromide, and cyanogen iodide. When the content of the compound having a triazine ring is within the above range, it is easy to control the polymerization reaction during production of a cured product, and a cyanate ester compound that is suitably used for producing a cured product having desired properties can be more preferably produced, and therefore cyanogen chloride is preferred as the cyanogen halide.

[0153] The amount of cyanogen halide used as a raw material is preferably 0.5 mol or more and 5.0 mol or less, more preferably 1.0 mol or more and 3.5 mol or less, relative to 1 mol of hydroxy groups of the hydroxy-substituted aromatic compound. When the amount of cyanogen halide used is within the above range, the content of the compound having a triazine ring is within the above range, making it easier to control the polymerization reaction during production of a cured product, and there is a tendency to more preferably produce a cyanate ester compound that is suitably used for producing a cured product having desired properties.

[0154] (Hydroxy-substituted aromatic compounds) Examples of hydroxy-substituted aromatic compounds include aromatic compounds having at least one phenolic hydroxy group. Examples of such hydroxy-substituted aromatic compounds include phenolic resins having a polynaphthylene ether structure and compounds represented by formula (27). Examples of compounds represented by formula (27) include (27a) 1-naphthol aralkyl resins, (27b) phenolic resins having an adamantane structure, and (27c) compounds other than (27a) and (27b) (hereinafter also referred to as "other hydroxy-substituted aromatic compounds"). These hydroxy-substituted aromatic compounds can be used alone or in combination of two or more.

[0155] Phenolic Resins Having a Polynaphthylene Ether Structure Examples of phenolic resins having a polynaphthylene ether structure include those having a polynaphthylene ether structure in which a naphthalene ring is bonded to another naphthalene ring via an oxy group, and a phenolic hydroxy group on the naphthalene ring. The total number of naphthalene rings per molecule is preferably 2 or more and 8 or less. The presence of a polynaphthylene ether structure promotes the formation of char (carbonized residue) during combustion of a cured product obtained from a cyanate ester, thereby exhibiting excellent flame retardancy and also improving heat resistance.

[0156] The number of oxy groups bonded to one naphthalene ring is preferably 1 to 3, and more preferably 2 from the viewpoint of the fluidity of the phenolic resin having a polynaphthylene ether structure. In this case, the bonding positions of the oxy groups on the naphthalene ring are preferably 1,3-positions, 1,6-positions, 1,7-positions, 1,8-positions, 2,3-positions, or 2,7-positions. Among these, from the viewpoint of ease of production, the bonding positions of the oxy groups on the naphthalene ring are more preferably 1,6-positions or 2,7-positions, and from the viewpoint of an excellent balance between fluidity and flame retardancy, the bonding positions are even more preferably 2,7-positions. Furthermore, with regard to the substituents on the naphthalene ring other than the oxy groups, from the viewpoint of flame retardancy, it is preferable that the naphthalene ring does not have such substituents.

[0157] The phenolic resin having a polynaphthylene ether structure may have a molecular structure in which a plurality of naphthalene rings form direct bonds.

[0158] Examples of the phenolic resin having a polynaphthylene ether structure include one or more selected from the group consisting of a compound represented by the following formula (21) and compounds represented by the following formulas (23) to (26) disclosed in Japanese Patent No. 4259536. As the phenolic resin having a polynaphthylene ether structure, a commercially available product may also be used, and an example of such a commercially available product is EXB-6000 from DIC Corporation.

[0159]

[0160] In formula (21), each R is independently a hydrogen atom, an aryl group such as a benzyl group, an alkyl group, or a group represented by the following formula (22), and n is an integer of 1 to 20, more preferably an integer of 1 to 10. Each group in formula (21) may have a substituent.

[0161]

[0162] In formula (22), each Ar is independently an aryl group such as a phenylene group or a naphthylene group, and m is an integer of 1 or 2.

[0163]

[0164]

[0165]

[0166]

[0167] A phenolic resin having a polynaphthylene ether structure can be obtained by a dehydration condensation reaction. The dehydration condensation reaction is a reaction in which, prior to the cyanation step, a polyhydroxynaphthalene compound having two or more phenolic hydroxy groups per molecule is subjected to a dehydration condensation reaction in the presence of a basic catalyst to obtain a hydroxy-substituted aromatic compound. The obtained hydroxy-substituted aromatic compound includes, for example, a phenolic resin having a structure in which a naphthalene ring is bonded to another naphthalene ring via an oxygen atom (hereinafter also referred to as an "oxy group") (hereinafter also referred to as a "polynaphthylene ether structure").

[0168] Examples of polyhydroxynaphthalene compounds used in the dehydration condensation reaction include dihydroxynaphthalenes such as 1,3-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 1,8-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, and 2,7-dihydroxynaphthalene; trihydroxynaphthalenes such as 1,2,3-trihydroxynaphthalene; and compounds of these compounds having an alkyl group having from 1 to 4 carbon atoms or a phenyl group as a substituent on the aromatic ring. These polyhydroxynaphthalene compounds can be used alone or in combination of two or more.

[0169] Examples of the basic catalyst used in the dehydration condensation reaction include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkali metal carbonates such as sodium carbonate and potassium carbonate, and phosphorus compounds such as triphenylphosphine. These basic catalysts can be used alone or in combination of two or more.

[0170] The amount of the basic catalyst used can be appropriately selected depending on the type thereof, the target reaction rate, etc. For example, when an alkali metal hydroxide is used as the basic catalyst, the amount of the basic catalyst used is preferably 0.01 mol or more and 0.5 mol or less, more preferably 0.01 mol or more and 0.1 mol or less, per 1 mol of the phenolic hydroxy group of the polyhydroxynaphthalene compound.

[0171] The dehydration condensation reaction can be carried out in the absence of a solvent or in the presence of a solvent, depending on the polyhydroxynaphthalene compound used. Carrying out the reaction in the absence of a solvent eliminates the need for a solvent recovery step. Carrying out the reaction in the presence of a solvent also makes it easier to form a homogeneous reaction solution, which tends to facilitate stable reaction.

[0172] Examples of solvents used in the dehydration condensation reaction include alcohols such as benzyl alcohol, cyclohexanol, and amyl alcohol; ethylene glycols such as ethylene glycol, diethylene glycol, triethylene glycol, and polyethylene glycol; mono- or diethers of ethylene glycol and diethylene glycol such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, and diethylene glycol dipropyl ether; chlorobenzene, nitrobenzene, and the like. These solvents may be used alone or in combination of two or more. The use of such solvents prevents the precipitation of a salt of a polyhydroxynaphthalene compound during the dehydration condensation reaction, allowing for the stable production of a phenolic resin having a polynaphthylene ether structure.

[0173] The reaction temperature of the dehydration condensation reaction is preferably 100° C. or higher and 300° C. or lower, more preferably 150° C. or higher and 250° C. or lower. The reaction time is also preferably within a range in which the above reaction temperature conditions can be maintained, and is usually 1 minute or higher and 10 hours or lower. In the dehydration condensation reaction, from the viewpoint of rapidly progressing the reaction and further improving productivity, it is preferable to distill off water generated during the reaction in association with the dehydration condensation reaction to the outside of the system using a fractionating column or the like.

[0174] After the dehydration condensation reaction is completed, the product is solidified as it is to extract the phenolic resin having a polynaphthylene ether structure, or the catalyst in the product is removed by neutralization, water washing, or decomposition, and the phenolic resin having a polynaphthylene ether structure can be separated by a general operation such as extraction or distillation. The neutralization and water washing can be carried out according to a conventional method, and for example, an acidic substance such as hydrochloric acid, oxalic acid, acetic acid, sodium monophosphate, or carbon dioxide gas can be used.

[0175] The phenolic resin having a polynaphthylene ether structure thus obtained can be used for various applications as it is, but if necessary, a fractionation procedure such as distillation, column treatment, or extraction with an aqueous alkali solution may be carried out to reduce the content of unreacted polyhydroxynaphthalene compounds, or each product may be isolated as a single component.

[0176] Compound Represented by Formula (27) Next, the compound represented by the following formula (27) will be described.

[0177]

[0178] In formula (27), Ar １ each independently represents a phenylene group, a naphthylene group, or a biphenylene group; each Ra independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms; １ m represents the number of hydroxy groups bonded to Ar, each independently being an integer of 1 to 3, １ each independently represents the number of bonds of Ra to Ar １ The number of substitutable groups is subtracted by (a+2), that is, Ar １is an integer of 4-1 when it is a phenylene group, an integer of 6-1 when it is a naphthylene group, and an integer of 8-1 when it is a biphenylene group; n is an integer of 0 to 50; and each X independently represents a single bond, a divalent organic group having 1 to 50 carbon atoms in which a hydrogen atom may be substituted with a heteroatom, a divalent organic group having 1 to 10 nitrogen atoms, a carbonyl group, a carboxy group, a carbonyl dioxide group, a sulfonyl group, a divalent sulfur atom, or a divalent oxygen atom. However, in formula (27), when n is 0, l is an integer of 2 to 3. Each group in formula (27) may have a substituent.

[0179] Ar １ each independently represents a phenylene group, a naphthylene group, or a biphenylene group in which a hydrogen atom at any position is substituted with an Ra group and a hydroxy group. These groups each may have a substituent.

[0180] In formula (27), examples of Ra and X include those similar to those exemplified as Ra and X in formula (1), and the repeating numbers 1, m, and n may refer to a, b, and c in formula (1), respectively.

[0181] X in formula (27) is preferably selected from the group consisting of divalent organic groups having 1 to 50 carbon atoms, as represented by the following formula (28), and divalent groups as represented by the following formulas (28a), (28b), (28c), (28d), (28e), (28f), (28g), (28h), (28i), and (28j).

[0182]

[0183] In formula (28), Ar ２each independently represent a phenylene group, a naphthylene group, or a biphenylene group, Rb, Rc, Rf, and Rg each independently represent a hydrogen atom, an alkyl group having from 1 to 6 carbon atoms, or an aryl group having from 6 to 12 carbon atoms, Rd and Re each independently represent a hydrogen atom, an alkyl group having from 1 to 6 carbon atoms, an aryl group having from 6 to 12 carbon atoms, an alkoxy group having from 1 to 4 carbon atoms, or a hydroxy group, and p represents an integer of from 0 to 5. Each group in formula (28) may have a substituent.

[0184]

[0185] In formula (28d), q represents an integer of 4 or more and 7 or less, and in formula (28i), each R independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

[0186] Ar in formula (28) ２ each independently represents a phenylene group, a naphthylene group, or a biphenylene group. ２ Examples of the alkyl group include a 1,4-phenylene group, a 1,3-phenylene group, a 2,6-naphthylene group, a 1,5-naphthylene group, a 1,6-naphthylene group, a 1,8-naphthylene group, a 1,3-naphthylene group, a 1,4-naphthylene group, a 4,4'-biphenylene group, a 2,4'-biphenylene group, a 2,2'-biphenylene group, a 2,3'-biphenylene group, a 3,3'-biphenylene group, and a 3,4'-biphenylene group.

[0187] Examples of Rb, Rc, Rd, Re, Rf, and Rg in formula (28) are the same as those exemplified for Rc, Rd, Re, Rf, Rg, and Rh in formula (3), respectively.

[0188] (27a) 1-Naphthol aralkyl resins Examples of 1-naphthol aralkyl resins include those having a structure in which a naphthalene ring having a hydroxyl group and a benzene ring are bonded via an alkyl group. Examples of such 1-naphthol aralkyl resins include those represented by the formula (27) where Ar １ is a naphthylene group, X is represented by formula (28), and Ar ２is a phenylene group. As the 1-naphthol aralkyl resin, a compound represented by the following formula (29) is preferred. In the compound represented by formula (29), the two methylene groups bonded to the benzene ring can be bonded at the ortho, meta, or para positions. Among these, it is preferable that the two methylene groups bonded to the benzene ring are bonded to the meta and / or para positions of the benzene ring. By using such a 1-naphthol aralkyl resin, the content of the compound having a triazine ring is within the above range, making it easier to control the polymerization reaction during production of a cured product, and it tends to be possible to more preferably produce a cyanate ester compound that is suitably used for producing a cured product having desired properties.

[0189]

[0190] In formula (29), n is an integer of 1 or more and 50 or less, and preferably an integer of 1 or more and 10 or less.

[0191] The 1-naphthol aralkyl resin can be prepared by, for example, reacting Ar ２ - (CH ２ Y) ２ and a naphthol compound in the presence of an acid catalyst or without a catalyst, ２ - (CH ２ OR) ２ Bis(alkoxymethyl) compounds represented by the formula: ２ - (CH ２ OH) ２ The compound can be obtained by reacting a bis(hydroxymethyl) compound represented by the following formula with a naphthol compound in the presence of an acid catalyst. Here, Y is a halogen atom, and R is an alkyl group. ２ is the same as that described in equation (28).

[0192] The 1-naphthol aralkyl resin may be a commercially available product, such as SN4 series phenolic resin (trade name, manufactured by Nippon Steel Chemical & Material Co., Ltd.).

[0193] (27b) Phenolic resin having an adamantane structure Examples of phenolic resins having an adamantane structure include those having a structure in which an aromatic ring having a hydroxy group is bonded to an adamantyl group. Examples of such phenolic resins include those in which, in formula (27), X is a group represented by formula (28i). Specific examples include compounds represented by the following formula (30). By using such compounds, the content of the compound having a triazine ring falls within the above range, making it easier to control the polymerization reaction during production of a cured product, and tending to more favorably produce cyanate ester compounds that are suitable for producing cured products with desired properties.

[0194]

[0195] In formula (30), Ar １ each independently represents a phenylene group, a naphthylene group, or a biphenylene group, R is the same as R in formula (28i), Ra is the same as Ra in formula (27), and l is Ar １ represents the number of hydroxy groups bonded to Ar, and is an integer of 1 to 3, １ represents the number of Ra bonded to Ar １ is an integer of 5-1 when it is a phenylene group, an integer of 7-1 when it is a naphthylene group, and an integer of 9-1 when it is a biphenylene group.

[0196] Examples of phenolic resins having such an adamantane structure include 1,3-bis(4-hydroxyphenyl)adamantane, 1,3-bis(4-hydroxyphenyl)-5,7-dimethyladamantane, 1,3-bis(4-hydroxyphenyl)-5-methyladamantane, 1,3-bis(4-hydroxyphenyl)-5-ethyladamantane, 1,3-bis(4-hydroxyphenyl)-5-propyladamantane, 1,3-bis(4-hydroxyphenyl)-5-isopropyladamantane, and 1,3-bis(4-hydroxyphenyl)-5-isopropyladamantane. 1,3-bis(4-hydroxyphenyl)-5-t-butyladamantane, 1,3-bis(4-hydroxyphenyl)-5,7-dimethyladamantane, 1,3-bis(4-hydroxyphenyl)-5-methyl-7-ethyladamantane, 1,3-bis(4-hydroxyphenyl)-5-methyl-7-propyladamantane, 1,3-bis(4-hydroxyphenyl)-5-ethyl-7-propyladamantane, 1,3-bis(4-hydroxyphenyl)-5,7-dipropyladamantane, 1,3-bis(4-hydroxyphenyl)-5-methyl-7-isopropyladamantane 1,3-bis(4-hydroxyphenyl)-5-ethyl-7-isopropyladamantane, 1,3-bis(4-hydroxyphenyl)-5-propyl-7-isopropyladamantane, 1,3-bis(4-hydroxyphenyl)-5,7-diisopropyladamantane, 1,3-bis(4-hydroxyphenyl)-5-methyl-7-t-butyladamantane, 1,3-bis(4-hydroxyphenyl)-5-ethyl-7-t-butyladamantane, 1,3-bis(4-hydroxyphenyl)-5-propyl-7-t-butyladamantane 1,3-bis(4-hydroxyphenyl)-5-isopropyl-7-t-butyladamantane, 1,3-bis(4-hydroxyphenyl)-5,7-di-t-butyladamantane, 1,3-bis(3-methyl-4-hydroxyphenyl)-5-methyladamantane, 1,3-bis(3-methyl-4-hydroxyphenyl)-5-ethyladamantane, 1,3-bis(3-methyl-4-hydroxyphenyl)-5-propyladamantane, 1,3-bis(3-methyl-4-hydroxyphenyl)-5-isopropyladamantane, 1,3-bis(3-methyl-4-hydroxyphenyl)-5-t-butyladamantane, 1,3-bis(3-methyl-4-hydroxyphenyl)-5,7-dimethyladamantane, 1,3-bis(3-methyl-4-hydroxyphenyl)-5-methyl-7-ethyladamantane, 1,3-bis(3-methyl-4-hydroxyphenyl)-5,7-diethyladamantane, 1,3-bis(3-methyl-4-hydroxyphenyl)-5-methyl-7-propyladamantane, 1,3-bis(3-methyl-4-hydroxyphenyl)-5-ethyl-7-propyladamantane propyladamantane, 1,3-bis(3-methyl-4-hydroxyphenyl)-5,7-dipropyladamantane, 1,3-bis(3-methyl-4-hydroxyphenyl)-5-methyl-7-isopropyladamantane, 1,3-bis(3-methyl-4-hydroxyphenyl)-5-ethyl-7-isopropyladamantane, 1,3-bis(3-methyl-4-hydroxyphenyl)-5-propyl-7-isopropyladamantane, 1,3-bis(3-methyl-4-hydroxyphenyl)-5,7-diisopropyladamantane, 1,3-bis( 1,3-bis(3-methyl-4-hydroxyphenyl)-5-methyl-7-t-butyladamantane, 1,3-bis(3-methyl-4-dihydroxyphenyl)-5-ethyl-7-t-butyladamantane, 1,3-bis(3-methyl-4-hydroxyphenyl)-5-propyl-7-t-butyladamantane, 1,3-bis(3-methyl-4-hydroxyphenyl)-5-isopropyl-7-t-butyladamantane, 1,3-bis(3-methyl-4-hydroxyphenyl)-5,7-di-t-butyladamantane, 1,3-bis(3,5-dimethyl-4-hydroxyphenyl)-5,7-di-t-butyladamantane, 1,3-bis(3,5-dimethyl-4-hydroxyphenyl)-5-methyladamantane, 1,3-bis(3,5-dimethyl-4-hydroxyphenyl)-5-ethyladamantane, 1,3-bis(3,5-dimethyl-4-hydroxyphenyl)-5-propyladamantane, 1,3-bis(3,5-dimethyl-4-hydroxyphenyl)-5-isopropyladamantane, 1,3-bis(3,5-dimethyl-4-hydroxyphenyl)-5-t-butyladamantane, 1,3-bis(3,5-dimethyl-4-hydroxyphenyl)-5,7-dimethyladamantane, 1,3-bis(3,1,3-bis(3,5-dimethyl-4-hydroxyphenyl)-5-methyl-7-ethyladamantane, 1,3-bis(3,5-dimethyl-4-hydroxyphenyl)-5,7-diethyladamantane, 1,3-bis(3,5-dimethyl-4-hydroxyphenyl)-5-methyl-7-propyladamantane, 1,3-bis(3,5-dimethyl-4-hydroxyphenyl)-5-ethyl-7-propyladamantane, 1,3-bis(3,5-dimethyl-4-hydroxyphenyl)-5,7-dipropyladamantane, 1,3-bis(3,5-dimethyl- 1,3-bis(3,5-dimethyl-4-hydroxyphenyl)-5-methyl-7-isopropyladamantane, 1,3-bis(3,5-dimethyl-4-hydroxyphenyl)-5-ethyl-7-isopropyladamantane, 1,3-bis(3,5-dimethyl-4-hydroxyphenyl)-5-propyl-7-isopropyladamantane, 1,3-bis(3,5-dimethyl-4-hydroxyphenyl)-5,7-diisopropyladamantane, 1,3-bis(3,5-dimethyl-4-hydroxyphenyl)-5-methyl-7-t-butyladamantane, 1,3-bis(3 ,5-dimethyl-4-hydroxyphenyl)-5-ethyl-7-t-butyladamantane, 1,3-bis(3,5-dimethyl-4-hydroxyphenyl)-5-propyl-7-t-butyladamantane, 1,3-bis(3,5-dimethyl-4-hydroxyphenyl)-5-isopropyl-7-t-butyladamantane, 1,3-bis(3,5-dimethyl-4-hydroxyphenyl)-5,7-di-t-butyladamantane, 1,3-bis(3-phenyl-4-hydroxyphenyl)-5-methyladamantane, 1,3-bis(3-phenyl-4-hydroxyphenyl)-5-methyladamantane, 1,3-bis(3-phenyl-4-hydroxyphenyl)-5-ethyladamantane, 1,3-bis(3-phenyl-4-hydroxyphenyl)-5-propyladamantane, 1,3-bis(3-phenyl-4-hydroxyphenyl)-5-isopropyladamantane, 1,3-bis(3-phenyl-4-hydroxyphenyl)-5-t-butyladamantane, 1,3-bis(3-phenyl-4-hydroxyphenyl)-5,7-dimethyladamantane, 1,3-bis(3-phenyl-4-hydroxyphenyl)-5-methyl-7-ethyladamantane,

[0197] 1,3-bis(3-phenyl-4-hydroxyphenyl)-5,7-diethyladamantane, 1,3-bis(3-phenyl-4-hydroxyphenyl)-5-methyl-7-propyladamantane, 1,3-bis(3-phenyl-4-hydroxyphenyl)-5-ethyl-7-propyladamantane, 1,3-bis(3-phenyl-4-hydroxyphenyl)-5,7-dipropyladamantane, 1,3-bis(3-phenyl-4-hydroxyphenyl)-5-methyl-7-isopropyladamantane, 1,3-bis(3-phenyl-4 -hydroxyphenyl)-5-ethyl-7-isopropyladamantane, 1,3-bis(3-phenyl-4-hydroxyphenyl)-5-propyl-7-isopropyladamantane, 1,3-bis(3-phenyl-4-hydroxyphenyl)-5,7-diisopropyladamantane, 1,3-bis(3-phenyl-4-hydroxyphenyl)-5-methyl-7-t-butyladamantane, 1,3-bis(3-phenyl-4-hydroxyphenyl)-5-ethyl-7-t-butyladamantane, 1,3-bis(3-phenyl-4-hydroxyphenyl)-5-methyl-7-t-butyladamantane, 1,3-bis(3-phenyl-4-hydroxyphenyl)-5-propyl-7-t-butyladamantane, 1,3-bis(3-phenyl-4-hydroxyphenyl)-5-isopropyl-7-t-butyladamantane, 1,3-bis(3-phenyl-4-hydroxyphenyl)-5,7-di-t-butyladamantane, 1,3-bis(3-cyclohexyl-4-hydroxyphenyl)-5-methyladamantane, 1,3-bis(3-cyclohexyl-4-hydroxyphenyl)-5-ethyladamantane, 1,3-bis(3-cyclohexyl-4-hydroxyphenyl)-5- Propyladamantane, 1,3-bis(3-cyclohexyl-4-hydroxyphenyl)-5-isopropyladamantane, 1,3-bis(3-cyclohexyl-4-hydroxyphenyl)-5-t-butyladamantane, 1,3-bis(3-cyclohexyl-4-hydroxyphenyl)-5,7-dimethyladamantane, 1,3-bis(3-cyclohexyl-4-hydroxyphenyl)-5-methyl-7-ethyladamantane, 1,3-bis(3-cyclohexyl-4-hydroxyphenyl)-5,7-diethyladamantane, 1,3-bis(3-cyclohexyl-4-hydroxyphenyl)-5-methyl-7-propyladamantane, 1,3-bis(3-cyclohexyl-4-hydroxyphenyl)-5-ethyl-7-propyladamantane, 1,3-bis(3-cyclohexyl-4-hydroxyphenyl)-5,7-dipropyladamantane, 1,3-bis(3-cyclohexyl-4-hydroxyphenyl)-5-methyl-7-isopropyladamantane, 1,3-bis(3-cyclohexyl-4-hydroxyphenyl)-5-ethyl-7-isopropyladamantane 1,3-bis(3-cyclohexyl-4-hydroxyphenyl)-5-propyl-7-isopropyladamantane, 1,3-bis(3-cyclohexyl-4-hydroxyphenyl)-5,7-diisopropyladamantane, 1,3-bis(3-cyclohexyl-4-hydroxyphenyl)-5-methyl-7-t-butyladamantane, 1,3-bis(3-cyclohexyl-4-hydroxyphenyl)-5-ethyl-7-t-butyladamantane, 1,3-bis(3-cyclohexyl-4-hydroxyphenyl)-5-propyl-7 -t-butyladamantane, 1,3-bis(3-cyclohexyl-4-hydroxyphenyl)-5-isopropyl-7-t-butyladamantane, 1,3-bis(3-cyclohexyl-4-hydroxyphenyl)-5,7-di-t-butyladamantane, 1,3-bis(4-methyl-2-hydroxyphenyl)-5-methyladamantane, 1,3-bis(4-methyl-2-hydroxyphenyl)-5-ethyladamantane, 1,3-bis(4-methyl-2-hydroxyphenyl)-5-propyladamantane, 1,3-bis(4-methyl 1,3-bis(4-methyl-2-hydroxyphenyl)-5-isopropyladamantane, 1,3-bis(4-methyl-2-hydroxyphenyl)-5-t-butyladamantane, 1,3-bis(4-methyl-2-hydroxyphenyl)-5,7-dimethyladamantane, 1,3-bis(4-methyl-2-hydroxyphenyl)-5-methyl-7-ethyladamantane, 1,3-bis(4-methyl-2-hydroxyphenyl)-5,7-diethyladamantane, 1,3-bis(4-methyl-2-hydroxyphenyl)-5-methyl-7-propyladamantane, 1,3-bis(4-methyl-2-hydroxyphenyl)-5-ethyl-7-propyladamantane, 1,3-bis(4-methyl-2-hydroxyphenyl)-5,7-dipropyladamantane, 1,3-bis(4-methyl-2-hydroxyphenyl)-5-methyl-7-isopropyladamantane, 1,3-bis(4-methyl-2-hydroxyphenyl)-5-ethyl-7-isopropyladamantane, 1,3-bis(4-methyl-2-hydroxyphenyl)-5-propyl-7-isopropyladamantane, 1,3-bis(4-methyl-2-hydroxyphenyl)-5,7-diisopropyladamantane Examples of such hydroxyphenyl compounds include 1,3-bis(4-methyl-2-hydroxyphenyl)-5-methyl-7-t-butyladamantane, 1,3-bis(4-methyl-2-hydroxyphenyl)-5-ethyl-7-t-butyladamantane, 1,3-bis(4-methyl-2-hydroxyphenyl)-5-propyl-7-t-butyladamantane, 1,3-bis(4-methyl-2-hydroxyphenyl)-5-isopropyl-7-t-butyladamantane, 1,3-bis(4-methyl-2-hydroxyphenyl)-5,7-di-t-butyladamantane, and 1,3-bis(2,4-dihydroxyphenyl)-adamantane.

[0198] (27c) Other Hydroxy-Substituted Aromatic Compounds Among the compounds represented by formula (27), examples of other hydroxy-substituted aromatic compounds other than 1-naphthol aralkyl resins and phenolic resins having an adamantane structure include 2,3-, 2,4-, 2,5-, 2,6-, 3,4-, or 3,5-xylenol, catechol, resorcinol, hydroquinone, 2-tert-butylhydroquinone, 2,4-dimethylhydroquinone, tetramethylhydroquinone, 2,4,6-trimethylresorcinol, 3,5-dihydroxytoluene, 2,2'-dihydroxy-1,1'-binaphthyl, 1, 3-, 1,4-, 1,5-, 1,6-, 1,7-, 2,3-, 2,6- or 2,7-dihydroxynaphthalene, 2,2'- or 4,4'-dihydroxybiphenyl, 4,4'-dihydroxyoctafluorobiphenyl, 2,2'- or 4,4'-dihydroxydiphenylmethane, bis(4-hydroxy-3,5-dimethylphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 1,1-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)methane 1,1-bis(4-hydroxyphenyl)propane, 2,2-bis(2-hydroxy-5-biphenylyl)propane, 2,2-bis(4-hydroxyphenyl)hexafluoropropane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 1,1-bis(4-hydroxyphenyl)butane, 1,1-bis(4-hydroxyphenyl)isobutane, 1,1-bis(4-hydroxyphenyl)pentane, 1,1-bis(4-hydroxyphenyl)-3-methylbutane, 1,1-bis(4-hydroxyphenyl)-2-methylbutane, 1,1-bis(4 -hydroxyphenyl)-2,2-dimethylpropane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)pentane, 2,2-bis(4-hydroxyphenyl)hexane, 2,2-bis(4-hydroxyphenyl)-3-methylbutane, 2,2-bis(4-hydroxyphenyl)-4-methylpentane, 2,2-bis(4-hydroxyphenyl)-3-methylpentane, 2,2-bis(4-hydroxyphenyl)-3,3-dimethylbutane, 3,3-bis(4-hydroxyphenyl)hexane, 3,3-bis(4-hydroxyphenyl)heptane, 3,3-bis(4-hydroxyphenyl)octane, 3,3-bis(4-hydroxyphenyl)-2-methylpentane, 3,3-bis(4-hydroxyphenyl)-2-methylhexane, 3,3-bis(4-hydroxyphenyl)-2,2-dimethylpentane, 4,4-bis(4-hydroxyphenyl)-3-methylheptane, 3,3-bis(4-hydroxyphenyl)-2-methylheptane, 3,3-bis(4-hydroxyphenyl)-2,2-dimethylhexane, 3,3-bis(4-hydroxyphenyl) bis(4-hydroxyphenyl)-2,4-dimethylhexane, 3,3-bis(4-hydroxyphenyl)-2,2,4-trimethylpentane, 2,2-bis(4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane, bis(4-hydroxyphenyl)phenylmethane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, bis(4-hydroxyphenyl)biphenylmethane, 1,1-bis(4-hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 2,2-bis(4-hydroxyphenyl)phenylmethane, 1,1-bis(3-cyclohexyl-4-hydroxyphenyl)propane, 1,1-bis(3-cyclohexyl-4-hydroxyphenyl)cyclohexane, bis(4-hydroxyphenyl)diphenylmethane, bis(4-hydroxyphenyl)-2,2-dichloroethylene, 1,3-bis[2-(4-hydroxyphenyl)-2-propyl]benzene, 1,4-bis[2-(4-hydroxyphenyl)-2-propyl]benzene, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 4-[bis(4-hydroxyphenyl)methyl]biphenyl phenyl, 4,4'-dihydroxybenzophenone, 1,3-bis(4-hydroxyphenyl)-2-propen-1-one, bis(4-hydroxyphenyl)ether, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)sulfone, 4-hydroxybenzoic acid-4-hydroxyphenyl ester (4-hydroxyphenyl-4-hydroxybenzoate), bis(4-hydroxyphenyl)carbonate, phenolphthalein, o-cresolphthalein, 9,9-bis(4-hydroxyphenyl)fluorene, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, 9,9-bis(2-hydroxy-5-biphenylyl)fluorene, tris(4-hydroxyphenyl)methane, 1,1,1-tris(4-hydroxyphenyl)ethane, 1,1,3-tris(4-hydroxyphenyl)propane, α,α,α'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene, 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane, 4,4 ',4'',4'''-Methanetetrayltetrakisphenol, 2,4,6-tris(N-methyl-4-hydroxyanilino)-1,3,5-triazine, 2,4-bis(N-methyl-4-hydroxyanilino)-6-(N-methylanilino)-1,3,5-triazine, bis(N-4-hydroxy-2-methylphenyl)-4,4'-oxydiphthalimide, bis(N-3-hydroxy-4-methylphenyl)-4,4'-oxydiphthalimide, bis(N-4- hydroxyphenyl)-4,4'-oxydiphthalimide, bis(N-4-hydroxy-2-methylphenyl)-4,4'-(hexafluoroisopropylidene)diphthalimide, tris(3,5-dimethyl-4-hydroxybenzyl)isocyanurate, 2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine, 2-(4-methylphenyl)-3,3-bis(4-hydroxyphenyl)phthalimidine, 2-phenyl-3,3-bis(4-hydroxy-3-methylphenyl)phthalimidine, 1-methyl-3,3-bis(4-hydroxyphenyl)indolin-2-one, 2-phenyl-3,3-bis(4-hydroxyphenyl)indolin-2-one, phenol novolac resin, cresol novolac resin, phenol aralkyl resin, cresol aralkyl resin, biphenyl aralkyl resin, phenol-modified xylene formaldehyde resin, and phenol-modified dicyclopentadiene resin.

[0199] Examples of phenol novolac resins and cresol novolac resins include those obtained by reacting phenol, alkyl-substituted phenol, or halogen-substituted phenol with a formaldehyde compound such as formalin or paraformaldehyde in an acidic solution by a known method.

[0200] Phenol aralkyl resins, cresol aralkyl resins, and biphenyl aralkyl resins can be prepared by, for example, the following known methods: ２ - (CH ２ Y) ２ and a phenol compound in the presence of an acid catalyst or without a catalyst, ２ - (CH ２ OR) ２ Bis(alkoxymethyl) compounds represented by the formula: ２ - (CH ２ OH) ２ and a phenol compound in the presence of an acid catalyst. Here, Y is a halogen atom. R is an alkyl group. ２ is the same as that described in equation (28).

[0201] Examples of phenol-modified xylene formaldehyde resins include those obtained by reacting a xylene formaldehyde resin with a phenol compound in the presence of an acid catalyst by a known method.

[0202] (Basic Compound) In the cyanation step, basic compounds 1 and 2 are used as desalting agents in the cyanation of a cyanogen halide and a hydroxy-substituted aromatic compound. Examples of such basic compounds include organic bases and inorganic bases. The basic compounds may be used in a solid state or in a solution state.

[0203] Preferred examples of the organic base include tertiary amines such as 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, and 1,5-diazabicyclo[4.3.0]-5-nonene. Among these, the basic compound is more preferably one or more selected from the group consisting of trimethylamine, triethylamine, tri-n-butylamine, and diisopropylethylamine, and even more preferably triethylamine. By using such a basic compound, the content of the compound having a triazine ring falls within the above range, which makes it easier to control the polymerization reaction during the production of a cured product, and tends to enable the production of a cyanate ester compound that is preferably used for producing a cured product having desired properties to be more preferably carried out in high yield.

[0204] As the inorganic base, for example, alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, and lithium hydroxide are preferred. Among these, sodium hydroxide is more preferred from the viewpoint of inexpensive availability.

[0205] In the cyanation step, the amount (total amount) of the basic compounds 1 and 2 used is preferably 0.1 mol or more and 8.0 mol or less, more preferably 1.0 mol or more and 6.0 mol or less, relative to 1 mol of hydroxy groups in the hydroxy-substituted aromatic compound. When the amount of the basic compounds used is within the above range, the content of the compound having a triazine ring is within the above range, making it easier to control the polymerization reaction during production of a cured product, and tends to make it possible to more preferably produce a cyanate ester compound suitable for producing a cured product having desired properties in high yield.

[0206] In the cyanation step, the basic compound can be used as a solution dissolved in water or an organic solvent. When the basic compound is an organic base, it is preferable to use an organic solvent, and when the basic compound is an inorganic base, it is preferable to use water.

[0207] When the solution containing a basic compound contains a hydroxy-substituted aromatic compound, the content of the solvent in the solution containing the basic compound is preferably 0.10 parts by mass or more and 100 parts by mass or less, more preferably 0.10 parts by mass or more and 80 parts by mass or less, relative to 1 part by mass of the hydroxy-substituted aromatic compound. Note that this solution containing the basic compound is, for example, solution 1 in the raw material solution preparation step.

[0208] When the solution containing the basic compound does not contain a hydroxy-substituted aromatic compound, the content of the solvent in the solution containing the basic compound is preferably 0.10 parts by mass or more and 100 parts by mass or less per part by mass of the basic compound. Note that this solution containing the basic compound becomes, for example, solution 3 in the cyanation step.

[0209] Examples of organic solvents and water may be found above. The organic solvent is preferably immiscible with water and inert to the cyanation reaction. By using an organic solvent immiscible with water, an organic solvent layer containing the cyanate ester compound can be separated from the reaction solution, which is a mixture of organic solvent and water, at the end of the cyanation step, thereby enabling separation of the cyanate ester compound.

[0210] [Resin Composition] The resin composition of the present embodiment contains the cyanate ester compound of the present embodiment. The cyanate ester compound may be used alone or in combination of two or more.

[0211] The content of the cyanate ester compound is preferably 1.0 part by mass or more and 100 parts by mass or less per 100 parts by mass of the resin solid content in the resin composition. When the content of the cyanate ester compound is within the above range, the resin composition tends to have better heat resistance, low dielectric constant, low dielectric loss tangent, etc.

[0212] The resin composition may further contain, as necessary, one or more compounds selected from the group consisting of cyanate ester compounds other than the cyanate ester compound of this embodiment (hereinafter also referred to as "other cyanate ester compounds"), epoxy resins, oxetane resins, maleimide compounds, phenolic resins, benzoxazine compounds, compounds having a polymerizable unsaturated group, and fillers. By having the above-mentioned configuration, the resin composition can produce a cured product that is excellent in flame retardancy, low water absorbency, moisture absorption heat resistance, heat resistance, low thermal expansion, low dielectric properties, low dielectric loss tangent, etc.

[0213] (Epoxy Resin) The resin composition may contain an epoxy resin. When the resin composition contains an epoxy resin, it tends to have better adhesiveness, moisture absorption heat resistance, flexibility, and the like. As the epoxy resin, for example, a generally known compound having two or more epoxy groups in one molecule can be used. Specific examples thereof include 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, multifunctional phenol type epoxy resin, naphthalene type epoxy resin, naphthalene skeleton-modified novolac type epoxy resin, naphthylene ether type epoxy resin, phenol aralkyl type epoxy resin, anthracene type epoxy resin, trifunctional phenol type epoxy resin, tetrafunctional phenol type epoxy resin, triglycidyl isocyanurate esters, glycidyl ester-type epoxy resins, alicyclic epoxy resins, dicyclopentadiene novolac-type epoxy resins, biphenyl novolac-type epoxy resins, phenol aralkyl novolac-type epoxy resins, naphthol aralkyl novolac-type epoxy resins, aralkyl novolac-type epoxy resins, biphenyl aralkyl-type epoxy resins, naphthol aralkyl-type epoxy resins, dicyclopentadiene-type epoxy resins, polyol-type epoxy resins, phosphorus-containing epoxy resins, glycidylamine, compounds in which the double bond of butadiene or the like has been epoxidized, compounds obtained by reacting hydroxyl-group-containing silicone resins with epichlorohydrin, or halides thereof. These epoxy resins may be used alone or in combination of two or more.

[0214] Among these, the epoxy resin is preferably at least one selected from the group consisting of biphenylaralkyl epoxy resins, naphthylene ether epoxy resins, polyfunctional phenolic epoxy resins, and naphthalene epoxy resins. When the resin composition contains such an epoxy resin, the flame retardancy and heat resistance of the resulting cured product tend to be further improved.

[0215] The content of the epoxy resin is preferably 0.0 part by mass or more and 99 parts by mass or less, more preferably 1.0 part by mass or more and 90 parts by mass or less, relative to 100 parts by mass of the resin solid content in the resin composition. When the content of the epoxy resin is within the above range, the adhesiveness, flexibility, etc. tend to be more excellent.

[0216] (Oxetane Resin) The resin composition may contain an oxetane resin. When the resin composition contains an oxetane resin, the resin composition tends to have better adhesiveness, flexibility, and the like. As the oxetane resin, a generally known oxetane resin can be used. Specific examples include alkyl oxetanes such as oxetane, 2-methyloxetane, 2,2-dimethyloxetane, 3-methyloxetane, and 3,3-dimethyloxetane, 3-methyl-3-methoxymethyloxetane, 3,3'-di(trifluoromethyl)perfluoxetane, 2-chloromethyloxetane, 3,3-bis(chloromethyl)oxetane, biphenyl oxetane, OXT-101 (trade name, manufactured by Toagosei Co., Ltd.), and OXT-121 (trade name, manufactured by Toagosei Co., Ltd.). These oxetane resins can be used alone or in combination of two or more.

[0217] The content of the oxetane resin is preferably 0.0 part by mass or more and 99 parts by mass or less, and more preferably 1.0 part by mass or more and 90 parts by mass or less, relative to 100 parts by mass of the resin solid content in the resin composition. When the content of the oxetane resin is within the above range, the resin composition tends to have better adhesion, flexibility, etc.

[0218] (Maleimide Compound) The resin composition may contain a maleimide compound. When the resin composition contains a maleimide compound, it tends to have better heat resistance, moisture absorption heat resistance, toughness, etc. As the maleimide compound, any generally known compound can be used as long as it has one or more maleimide groups in one molecule. Specific examples thereof include 4,4'-diphenylmethane bismaleimide, phenylmethane maleimide, m-phenylene bismaleimide, 2,2-bis(4-(4-maleimidophenoxy)-phenyl)propane, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide, 1,6-bismaleimide-(2,2,4-trimethyl)hexane, 4,4'-diphenylether bismaleimide, 4,4'-diphenylsulfone bismaleimide, 1,3-bis(3-maleimidophenoxy)benzene, 1,3-bis(4-maleimidophenoxy)benzene, polyphenylmethane maleimide, and prepolymers of these maleimide compounds, or prepolymers of maleimide compounds and amine compounds. These maleimide compounds can be used alone or in combination of two or more.

[0219] The content of the maleimide compound is preferably 0.0 part by mass or more and 99 parts by mass or less, and more preferably 1.0 part by mass or more and 90 parts by mass or less, relative to 100 parts by mass of the resin solid content in the resin composition. When the content of the maleimide compound is within the above range, the heat resistance and the like tend to be more excellent.

[0220] (Phenolic Resin) The resin composition may contain a phenolic resin. When the resin composition contains a phenolic resin, the resin composition tends to have better adhesiveness, flexibility, and the like. As the phenolic resin, any commonly known phenolic resin having two or more hydroxy groups per molecule can be used. Specific examples include bisphenol A phenolic resin, bisphenol E phenolic resin, bisphenol F phenolic resin, bisphenol S phenolic resin, phenol novolac resin, bisphenol A novolac phenolic resin, aralkyl novolac phenolic resin, biphenyl aralkyl phenolic resin, cresol novolac phenolic resin, multifunctional phenolic resin, naphthol resin, naphthol novolac resin, multifunctional naphthol resin, anthracene phenolic resin, naphthalene skeleton-modified novolac phenolic resin, phenol aralkyl phenolic resin, naphthol aralkyl phenolic resin, dicyclopentadiene phenolic resin, biphenyl phenolic resin, alicyclic skeleton-containing phenolic resin, phosphorus-containing phenolic resin, and hydroxyl group-modified silicone resin. These phenolic resins can be used alone or in combination of two or more.

[0221] The content of the phenolic resin is preferably 0.0 parts by mass or more and 99 parts by mass or less, more preferably 1.0 parts by mass or more and 90 parts by mass or less, relative to 100 parts by mass of the resin solid content in the resin composition. When the content of the phenolic resin is within the above range, the adhesiveness, flexibility, etc. tend to be more excellent.

[0222] (Benzoxazine Compound) The resin composition may contain a benzoxazine compound. When the resin composition contains a benzoxazine compound, it tends to have better flame retardancy, heat resistance, low water absorption, low dielectric constant, and the like. As the benzoxazine compound, any generally known compound having two or more dihydrobenzoxazine rings in one molecule can be used. Specific examples include bisphenol A-type benzoxazine BA-BXZ (trade name, manufactured by Konishi Chemical Industry Co., Ltd.), bisphenol F-type benzoxazine BF-BXZ (trade name, manufactured by Konishi Chemical Industry Co., Ltd.), and bisphenol S-type benzoxazine BS-BXZ (trade name, manufactured by Konishi Chemical Industry Co., Ltd.). These benzoxazine compounds can be used alone or in combination of two or more.

[0223] The content of the benzoxazine compound is preferably 0.0 part by mass or more and 99 parts by mass or less, more preferably 1.0 part by mass or more and 90 parts by mass or less, relative to 100 parts by mass of the resin solid content in the resin composition. When the content of the benzoxazine compound is within the above range, the heat resistance and the like tend to be more excellent.

[0224] (Compound Having a Polymerizable Unsaturated Group) The resin composition may contain a compound having a polymerizable unsaturated group. When the resin composition contains a compound having a polymerizable unsaturated group, the resin composition tends to have better heat resistance, toughness, and the like. As the compound having a polymerizable unsaturated group, generally known compounds can be used. Specific examples include vinyl compounds such as ethylene, propylene, styrene, divinylbenzene, and divinylbiphenyl; (meth)acrylates of monohydric or polyhydric alcohols such as methyl(meth)acrylate, 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, polypropylene glycol di(meth)acrylate, trimethylolpropane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate; epoxy(meth)acrylates such as bisphenol A-type epoxy(meth)acrylate and bisphenol F-type epoxy(meth)acrylate; and benzocyclobutene resins. These compounds having a polymerizable unsaturated group may be used alone or in combination of two or more.

[0225] The content of the compound having a polymerizable unsaturated group is preferably 0.0 part by mass or more and 99 parts by mass or less, more preferably 1.0 part by mass or more and 90 parts by mass or less, relative to 100 parts by mass of the resin solid content in the resin composition. When the content of the compound having a polymerizable unsaturated group is within the above range, the heat resistance, toughness, etc. tend to be more excellent.

[0226] (Filler) The resin composition may contain a filler. When the resin composition contains a filler, it tends to have better flame retardancy, low thermal expansion, high thermal conductivity, toughness, etc. Examples of the filler include inorganic fillers and organic fillers. These fillers can be used alone or in combination of two or more.

[0227] As the inorganic filler, generally known ones can be used. Specific examples thereof include silicates such as kaolin, calcined kaolin, talc, calcined talc, calcined clay, uncalcined clay, mica, E glass, A glass, NE glass, C glass, L glass, D glass, S glass, M glass G20, glass short fiber (including glass fine powders such as E glass, T glass, D glass, S glass, and Q glass), hollow glass, and spherical glass; silicas such as white carbon (wet silica), natural silica, fused silica, synthetic silica, amorphous silica, aerosil, and hollow silica; oxides such as titanium oxide, alumina, boehmite, zinc oxide, magnesium oxide, and zirconium oxide; calcium carbonate, magnesium carbonate, hydrogel Examples of inorganic fillers include carbonates such as talcite; hydroxides such as aluminum hydroxide, heat-treated aluminum hydroxide (aluminum hydroxide that has been heat-treated to remove some of the water of crystallization), magnesium hydroxide, and calcium hydroxide; sulfates or sulfites such as barium sulfate, calcium sulfate, and calcium sulfite; borates such as zinc borate, barium metaborate, aluminum borate, calcium borate, and sodium borate; nitrides such as aluminum nitride, boron nitride, aggregated boron nitride, silicon nitride, and carbon nitride; titanates such as strontium titanate and barium titanate; stannates such as zinc stannate; and molybdenum compounds such as molybdenum oxide and zinc molybdate. These inorganic fillers can be used alone or in combination of two or more.

[0228] Examples of organic fillers include rubber powders such as styrene powder, butadiene powder, and acrylic powder; core-shell rubber powder; silicone resin powder; silicone rubber powder; silicone composite powder; etc. These organic fillers can be used alone or in combination of two or more.

[0229] The filler may be used in combination with a silane coupling agent or a wetting and dispersing agent. The resin composition may contain one or more agents selected from the group consisting of silane coupling agents and wetting and dispersing agents.

[0230] As the silane coupling agent, those generally used for the surface treatment of inorganic or organic substances can be suitably used. Specific examples include aminosilanes such as γ-aminopropyltriethoxysilane and N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, epoxysilanes such as γ-glycidoxypropyltrimethoxysilane and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, vinylsilanes such as γ-methacryloxypropyltrimethoxysilane and vinyl-tri(β-methoxyethoxy)silane, cationic silanes such as N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane hydrochloride, and phenylsilanes. These silane coupling agents can be used alone or in combination of two or more.

[0231] As the wetting and dispersing agent, those generally used for paints can be suitably used. Preferably, a copolymer-based wetting and dispersing agent is used. Specific examples include Disperbyk (registered trademark)-110, 111, 161, 180 (all trade names), BYK (registered trademark)-W996, BYK-W9010, BYK-W903, BYK-W940 (all trade names) manufactured by BYK Japan K.K. These wetting and dispersing agents can be used alone or in combination of two or more.

[0232] The content of the filler is preferably 0.0 parts by mass or more and 1600 parts by mass or less, more preferably 50 parts by mass or more and 1600 parts by mass or less, relative to 100 parts by mass of the resin solid content in the resin composition. When the content of the filler is within the above range, the flame retardancy, low thermal expansion property, toughness, etc. tend to be better.

[0233] (Polymerization Catalyst and Curing Accelerator) In addition to the compounds or resins described above, the resin composition may further contain a polymerization catalyst and / or a curing accelerator for appropriately adjusting the curing rate. Generally known polymerization catalysts and curing accelerators can be used. Specific examples include organic metal salts such as zinc octylate, zinc naphthenate, cobalt naphthenate, copper naphthenate, iron acetylacetonate, nickel octylate, and manganese octylate; phenolic compounds such as phenol, xylenol, cresol, resorcinol, catechol, 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-dihydroxymethylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-hydroxyimidazole. Examples of the compound include imidazole derivatives such as methylimidazole; derivatives of these imidazoles such as adducts of carboxylic acids or acid anhydrides thereof; amine compounds such as dicyandiamide, benzyldimethylamine, and 4-methyl-N,N-dimethylbenzylamine; phosphorus compounds such as phosphine compounds, phosphine oxide compounds, phosphonium compounds, and diphosphine compounds; peroxides such as epoxy-imidazole adduct compounds, benzoyl peroxide, p-chlorobenzoyl peroxide, di-t-butyl peroxide, diisopropyl peroxycarbonate, and di-2-ethylhexyl peroxycarbonate; and azo compounds such as azobisisobutyronitrile. These polymerization catalysts and curing accelerators may be commercially available products, and examples of such commercially available products include Amicure (registered trademark) PN-23 (trade name, manufactured by Ajinomoto Fine-Techno Co., Inc.), Novacure (registered trademark) HX-3721 (trade name, manufactured by Asahi Kasei Corporation), and Fujicure (registered trademark) FX-1000 (trade name, manufactured by Fuji Chemical Industry Co., Ltd.). These polymerization catalysts and curing accelerators may be used alone or in combination of two or more.

[0234] The contents of the polymerization catalyst and curing accelerator can be adjusted as appropriate taking into consideration the degree of curing of the resin, the viscosity of the resin composition, etc., but are usually 0.005 parts by mass or more and 10 parts by mass or less, respectively, per 100 parts by mass of the resin solid content in the resin composition.

[0235] (Other Additives) The resin composition may contain additives other than the above-mentioned compounds or resins, polymerization catalysts, and curing rate enhancers, as needed. Examples of such additives include known additives such as thermosetting resins other than the above-mentioned compounds or resins, thermoplastic resins and their oligomers, various polymeric compounds such as elastomers, coloring pigments, defoamers, surface conditioners, flame retardants, solvents, UV absorbers, antioxidants, photopolymerization initiators, fluorescent brighteners, photosensitizers, dyes, pigments, thickeners, lubricants, flow adjusters, defoamers, dispersants, leveling agents, gloss agents, and polymerization inhibitors. These additives may be used alone or in combination of two or more.

[0236] The content of each additive is usually 0.005 parts by mass or more and 10 parts by mass or less relative to 100 parts by mass of the resin solid content in the resin composition.

[0237] (Organic Solvent) The resin composition may contain an organic solvent as needed. In this case, the resin composition can be used in a form (solution or varnish) in which at least a part, preferably all, of the various resin components described above are dissolved or compatible with the organic solvent.

[0238] Any known organic solvent can be used as long as it is capable of dissolving or being compatible with at least a portion, preferably all, of the various resin components described above. Specific examples include ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; cellosolve-based solvents such as propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate; ester-based solvents such as ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, isoamyl acetate, ethyl lactate, methyl methoxypropionate, and methyl hydroxyisobutyrate; polar solvents such as amides such as dimethylacetamide and dimethylformamide; alcohol-based solvents such as methanol, ethanol, isopropanol, and 1-ethoxy-2-propanol; and aromatic hydrocarbons such as toluene, xylene, and anisole. These organic solvents can be used alone or in combination of two or more.

[0239] The resin composition can be obtained by mixing the cyanate ester compound of the present embodiment and, as necessary, other components together with an organic solvent using a known mixer, for example, a high-speed mixer, a Nauta mixer, a ribbon blender, a kneader, an intensive mixer, a universal mixer, a dissolver, a static mixer, etc. The method of adding the cyanate ester compound, various additives, and the solvent during mixing is not particularly limited.

[0240] [Applications] The cyanate ester compound and resin composition of this embodiment are suitable for use in, for example, cured products, prepregs, laminates, metal foil-clad laminates, multilayer plates, sealing materials, fiber-reinforced composite materials, adhesives, resin composite sheets, films, and printed wiring boards. Furthermore, the cyanate ester compound and resin composition are useful as high-performance polymer materials due to, for example, their low thermal expansion, flame retardancy, and heat resistance. Furthermore, the cyanate ester compound and resin composition can be used as, for example, materials with excellent thermal, electrical, and mechanical properties. Examples of such materials include electrical insulating materials, sealing materials, adhesives, laminate materials, resists, and build-up laminate materials, as well as fixing materials, structural members, reinforcing agents, and molding materials in fields such as civil engineering and construction, electrical and electronics, automobiles, railways, ships, aircraft, sporting goods, and arts and crafts. Among these, the cyanate ester compound and resin composition are suitable for use in electrical insulating materials, semiconductor sealing materials, adhesives for electronic components, aircraft structural members, satellite structural members, and railway vehicle structural members, which require low thermal expansion, heat resistance, and high mechanical strength.

[0241] [Cured Product] The cured product of this embodiment is obtained by curing the resin composition of this embodiment. The cured product can be produced, for example, by melting or dissolving the resin composition in a solvent, pouring it into a mold, and curing it under normal conditions using heat, light, or the like. In the case of thermal curing, the curing temperature is preferably in the range of 120°C or higher and 300°C or lower, from the viewpoint of efficiently curing and preventing deterioration of the resulting cured product. In the case of photocuring, the light wavelength range is preferably in the range of 100 nm or higher and 500 nm or lower, in which curing efficiently proceeds using a photopolymerization initiator or the like.

[0242] [Prepreg] The prepreg includes a substrate and the resin composition of the present embodiment impregnated into or coated on the substrate. The prepreg can be used as an insulating layer for a printed wiring board and a material for a semiconductor package.

[0243] (Substrate) As the substrate, a generally known substrate can be appropriately selected and used depending on the performance required for the prepreg, such as strength, water absorption, and thermal expansion coefficient. Specific examples include glass fiber substrates, synthetic fiber substrates, organic fiber substrates, and inorganic fiber substrates. Examples of glass fibers constituting the glass fiber substrate include A-glass, C-glass, D-glass, E-glass, H-glass, L-glass, NE-glass, Q-glass, S-glass, T-glass, UN-glass, and spherical glass. Examples of synthetic fibers constituting the synthetic fiber substrate include polyamide-based resin fibers such as polyamide resin fibers, aromatic polyamide resin fibers, and wholly aromatic polyamide resin fibers; polyester-based resin fibers such as polyester resin fibers, aromatic polyester resin fibers, and wholly aromatic polyester resin fibers; polyimide resin fibers; and fluororesin fibers. Examples of organic fiber substrates include paper substrates primarily composed of kraft paper, cotton linter paper, and mixed paper of linter and kraft pulp. Examples of inorganic fibers constituting the inorganic fiber substrate include inorganic fibers other than glass, such as quartz. Examples of the substrate shape include woven fabric, nonwoven fabric, roving, chopped strand mat, and surfacing mat. The substrate can be used alone or in combination of two or more. Furthermore, the thickness of the substrate is preferably in the range of 0.01 mm to 0.2 mm for laminate applications. When the substrate is within the above thickness range, woven fabrics that have been subjected to an opening treatment or a clogging treatment are suitable from the viewpoint of dimensional stability. Furthermore, glass woven fabrics that have been surface-treated with a silane coupling agent such as epoxy silane treatment or amino silane treatment are preferred from the viewpoint of moisture absorption and heat resistance. Liquid crystal polyester woven fabrics are also preferred from the viewpoint of electrical properties.

[0244] As a method for producing a prepreg, a generally known method can be appropriately applied. For example, a prepreg can be produced by preparing a resin varnish using a resin composition and immersing a substrate in the resin varnish, applying the resin varnish to the substrate using various coaters, or spraying the resin varnish onto the substrate using a spray. Among these, the method of immersing the substrate in the resin varnish is preferred. This improves the impregnation of the resin composition into the substrate. When immersing the substrate in the resin varnish, a conventional impregnation coating device can be used. For example, a method can be applied in which an inorganic and / or organic fiber substrate is impregnated with the resin varnish using impregnation coating device, and the resin varnish is dried at 120°C to 220°C for approximately 2 minutes to 15 minutes, resulting in a B-stage to produce a prepreg. In this case, the amount of the resin composition attached to the substrate, i.e., the amount of the resin composition (including the filler) relative to the total amount (100% by mass) of the semi-cured prepreg, is preferably in the range of 20% by mass to 99% by mass.

[0245] [Laminate] A laminate has a layer containing at least one prepreg and metal foil laminated on one or both sides of the layer. A commonly known method can be appropriately applied as a method for manufacturing a laminate. For example, a laminate can be obtained by laminating a prepreg and a metal foil and then hot-pressing the laminate. The heating temperature is preferably 65°C or higher and 300°C or lower, more preferably 120°C or higher and 270°C or lower. The pressure applied is preferably 2.0 MPa or higher and 5.0 MPa or lower, more preferably 2.5 MPa or higher and 4.0 MPa or lower. The laminate can also be used as a metal foil-clad laminate or a multilayer board.

[0246] [Metal Foil-Clad Laminate] A metal foil-clad laminate is a laminate formed by stacking at least one prepreg and disposing a metal foil on one or both sides of the prepreg. Specifically, it can be produced by stacking one or more prepregs and disposing a metal foil such as copper or aluminum on one or both sides of the prepreg, followed by lamination molding. Examples of metal foil include those used in printed wiring board materials. Examples of such metal foils include copper foils such as rolled copper foil and electrolytic copper foil. The thickness of the metal foil is preferably 2.0 μm to 70 μm, more preferably 3.0 μm to 35 μm. Conventional methods for laminates and multilayer boards for printed wiring boards can be applied as molding conditions. For example, a multi-stage press, a multi-stage vacuum press, a continuous molding machine, an autoclave molding machine, or the like can be used at a temperature of 180°C to 350°C, a heating time of 100 minutes to 300 minutes, and a surface pressure of 20 kg / cm. ２ More than 100kg / cm ２ A metal foil-clad laminate can be manufactured by laminating and molding as follows.

[0247] [Multilayer board] A multilayer board can be obtained by combining prepreg and a separately prepared inner layer wiring board and laminating them together.As a method for producing a multilayer board, for example, 35 μm copper foil is placed on both sides of one prepreg, and then laminated under the above conditions, an inner layer circuit is formed, and this circuit is subjected to blackening treatment to form an inner layer circuit board.Then, this inner layer circuit board and the above prepreg are alternately arranged one by one, and copper foil is placed on the outermost layer, and laminated under the above conditions, preferably under vacuum, to produce the multilayer board.

[0248] [Sealing Material] The sealing material includes a resin composition. A generally known method can be appropriately applied as a method for producing the sealing material. For example, a method of mixing the resin composition with various known additives or solvents generally used in sealing material applications using a known mixer can be mentioned. Note that, when mixing, a generally known method can be appropriately applied as a method for adding the cyanate ester compound, various additives, and solvent.

[0249] [Fiber-reinforced composite material] The fiber-reinforced composite material contains a resin composition and reinforcing fibers. Generally known reinforcing fibers can be used. Specific examples 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 can be appropriately selected from, for example, woven fabrics, nonwoven fabrics, mats, knits, braided cords, unidirectional strands, rovings, and chopped fibers. Preforms (layers of woven fabric base fabrics made of reinforcing fibers, or fabrics sewn together with stitching threads, or fiber structures such as three-dimensional woven fabrics and braided fabrics) can also be used as the form of the reinforcing fibers.

[0250] Generally known methods can be used as appropriate for producing fiber-reinforced composite materials. Specific examples include liquid composite molding, resin film infusion, filament winding, hand layup, and pultrusion. Among these, resin transfer molding, which is one type of liquid composite molding, allows materials other than preforms, such as metal plates, foam cores, and honeycomb cores, to be placed in the mold beforehand, making it suitable for a variety of applications. Therefore, it is preferably used for mass-producing composite materials with relatively complex shapes in a short period of time.

[0251] [Adhesive] The adhesive includes the resin composition of this embodiment. A generally known method can be appropriately applied as a method for producing the adhesive. For example, such a production method includes a method of mixing the resin composition with various known additives or solvents generally used in adhesive applications using a known mixer. Note that, when mixing, a generally known method can be appropriately applied as a method for adding the cyanate ester compound, various additives, and solvent.

[0252] [Resin Composite Sheet] The resin composite sheet includes a support and a resin layer disposed on the surface of the support, the resin layer containing the resin composition of this embodiment. The resin composite sheet can also be obtained by applying a solution of the resin composition of this embodiment dissolved in a solvent to a support and drying the resulting solution. Examples of the support include polyethylene film, polypropylene film, polycarbonate film, polyethylene terephthalate film, ethylene tetrafluoroethylene copolymer film, and release films obtained by applying a release agent to the surface of these films; organic film substrates such as polyimide film; conductive foils such as copper foil and aluminum foil; glass plates, SUS plates, and FRP plates. Examples of application methods include applying a solution of the resin composition dissolved in a solvent to the support using a bar coater, die coater, doctor blade, baker applicator, or the like. After drying, the support can be peeled or etched from the laminate sheet to form a single-layer sheet (resin sheet). In addition, a single-layer sheet (resin sheet) can also be obtained without using a support by supplying a solution of the resin composition dissolved in a solvent into a mold having a sheet-shaped cavity and drying it to form it into a sheet.

[0253] In producing a single-layer or laminate sheet, the drying conditions for removing the solvent are preferably a temperature of 20° C. or higher and 200° C. or lower for 1 minute or longer and 90 minutes or shorter, since low temperatures tend to leave the solvent in the resin composition, and high temperatures tend to accelerate curing of the resin composition. The thickness of the resin layer of the single-layer or laminate sheet can be adjusted by the concentration of the resin composition solution and the coating thickness, but generally, a thicker coating thickness tends to leave the solvent during drying, so the thickness is preferably 0.1 μm or longer and 500 μm or shorter.

[0254] [Film] The film is formed by molding the resin composition into a sheet. Such a film can be used, for example, as a build-up film or a dry film solder resist. Examples of methods for producing the film include using a peelable plastic film as a substrate, applying a solution of the resin composition dissolved in a solvent to the plastic film, and drying the applied solution. The solvent can be dried by heating at a temperature of 20°C to 150°C for 1 minute to 90 minutes. The film can be used in an uncured state, in which the solvent has simply been dried from the resin composition, or, if necessary, in a semi-cured (B-staged) state.

[0255] [Printed Wiring Board] The printed wiring board includes an insulating layer and a conductor layer formed on the surface of the insulating layer, and the insulating layer includes a resin composition. That is, it is preferable that the insulating layer is composed of an insulating layer including the resin composition of the present embodiment.

[0256] Metal foil-clad laminates can be suitably used as printed wiring boards. Printed wiring boards can be manufactured according to conventional methods. An example of a method for manufacturing a printed wiring board is shown below. First, a metal foil-clad laminate, such as a copper-clad laminate, is prepared. Next, the surface of the metal foil-clad laminate is etched to form an inner layer circuit, thereby producing an inner layer substrate. The inner layer circuit surface of this inner layer substrate is then subjected to a surface treatment to enhance adhesive strength, if necessary. A required number of prepregs are then stacked on the inner layer circuit surface, and a metal foil for an outer layer circuit is further laminated on the outer surface, followed by heating and pressurization to form an integral mold. In this way, a multilayer laminate is manufactured, in which an insulating layer consisting of a substrate and a cured resin composition is formed between the inner layer circuit and the metal foil for the outer layer circuit. Next, the multilayer laminate is drilled for through holes or via holes, and a plated metal film that connects the inner layer circuit and the metal foil for the outer layer circuit is formed on the wall surface of the hole, providing electrical continuity between the inner layer circuit and the metal foil for the outer layer circuit. The metal foil for the outer layer circuit is then etched to form the outer layer circuit, thereby manufacturing a printed wiring board.

[0257] The present invention will be described in more detail below with reference to examples, although the present invention is not particularly limited to the following examples.

[0258] [Calculation and Measurement Methods] (1) Content of Compound Having Triazine Ring The content (area %) of the compound having a triazine ring in the cyanate ester compounds obtained in the Examples and Comparative Examples was measured as follows. That is, 2.0 g of a 2-butanone solution containing 50% by mass of the cyanate ester compound was dissolved in 50 g of tetrahydrofuran (solvent) to obtain a solution. 2.0 μL of this solution was injected into a high-performance liquid chromatograph (High-Performance Liquid Chromatograph LachromElite (trade name), Hitachi High-Tech Corporation) for analysis. The column used was a TSKgel ODS-120T (length 25 cm × inner diameter 4.6 mm) manufactured by Tosoh Corporation, and the mobile phase was acetonitrile / water (80 / 20 volume ratio). The flow rate was 1.0 mL / min, the detection wavelength was 274 nm, and the column temperature was 35°C. The content of the compound having a triazine ring in the cyanate ester compound was calculated from the peak area value of the peak with a retention time (RT) of 1.5 minutes.

[0259] (2) Peak Top Temperature The exothermic peak temperature (peak top temperature, °C) of the cyanate ester compounds obtained in the examples and comparative examples was measured as follows. First, as a pretreatment, 5.0 g of a 2-butanone solution containing 50% by mass of the cyanate ester compound was concentrated under reduced pressure, and then further concentrated to dryness at 70°C for 1 hour to obtain 2.7 g of a cyanate ester compound. The peak top temperature (unit: °C) was measured by observing the exothermic behavior of the obtained cyanate ester compound using a differential scanning calorimeter (DSC7020 (trade name), manufactured by SII NanoTechnology Inc.) under measurement conditions of an initial temperature of 40°C, an end temperature of 380°C, and a heating rate of 3.0°C / min. Note that a higher peak top temperature indicates easier control of the polymerization reaction.

[0260] Example 1 A 0.3 L glass flask with a releasable lid and a stirrer was prepared. Nitrogen was circulated through the flask at a rate of 16.0 L / hour per 1 L of the container. 40 g of 1-naphthol aralkyl resin (SN495V, product name, manufactured by Nippon Steel Chemical & Material Co., Ltd.) as a hydroxy-substituted aromatic compound (hydroxy group equivalent: 230 g / eq., hydroxy group equivalent: 0.17 mol) and 26.4 g of triethylamine (0.26 mol, an amount equivalent to 1.5 mol per mol of hydroxy groups in the 1-naphthol aralkyl resin) as a basic compound 1 were dissolved in 240 g of dichloromethane as an organic solvent 1 while maintaining a solution temperature of 0°C. This solution was designated Solution 1.

[0261] A mixed liquid (solution 2) of 16.0 g (0.26 mol, 1.50 mol relative to 1 mol of hydroxy groups in the 1-naphthol aralkyl resin) of cyanogen chloride as cyanogen halide, 37.4 g of dichloromethane as organic solvent 2, 26.4 g (0.26 mol, 1.50 mol relative to 1 mol of hydroxy groups in the 1-naphthol aralkyl resin) of 36% hydrochloric acid as hydrogen halide, and 163.8 g of water was stirred and kept at a liquid temperature of −3 to −1° C., and into this mixed liquid was added the solution 1 obtained above over 12 minutes, thereby obtaining solution 2. Thereafter, while maintaining the liquid temperature at -3 to -1°C, Solution 2 was further stirred for 5 minutes, and then, while maintaining the liquid temperature at -3 to -1°C, Solution 3, prepared by dissolving 7.0 g of triethylamine (0.07 mol, 0.40 mol per mol of hydroxy groups in the 1-naphthol aralkyl resin) as basic compound 2 in 7.0 g of dichloromethane as organic solvent 3, was poured into Solution 2 over 2 minutes to obtain Solution 4, while maintaining the liquid temperature at -3 to -1°C. Thereafter, while maintaining the liquid temperature at -3 to -1°C, Solution 4 was further stirred for 30 minutes to complete the reaction, thereby obtaining Reaction Solution 1. The pH of the aqueous phase (upper phase) of Reaction Solution 1 was measured using a pH meter (IQ Scientific Instruments, IQ150 (trade name)) and was found to be 0.9.

[0262] Thereafter, the reaction solution 1 was allowed to stand, and the lower organic phase (dichloromethane phase) and the upper aqueous phase were accurately separated at the interface so as not to be mixed with each other. At this time, both phases were transparent.

[0263] The resulting dichloromethane phase was heated and distilled until the bottom liquid temperature reached a maximum of 41°C, at which point cyanogen chloride and dichloromethane were distilled off. Then, fresh dichloromethane equivalent to the distilled mass was added to the substrate. The resulting solution was then washed five times with 200 g of water. The electrical conductivity of the wastewater after the fifth water wash was measured using a portable EC meter (HI8733N, product name, manufactured by Hanna Instruments) and found to be 10 μS / cm. This electrical conductivity value confirmed that ionic compounds had been sufficiently removed by washing with water.

[0264] The dichloromethane phase after washing with water was concentrated under reduced pressure, and solvent substitution with 2-butanone solution was repeated five times to obtain 86.9 g of a 2-butanone solution containing 50 mass % of the target cyanate ester compound (compound represented by formula (17)). The content of the compound having a triazine ring (compound containing a structure represented by formula (18)) in the obtained cyanate ester compound was 1.4 area % in terms of HPLC area percentage, and the peak top temperature was 278°C. These results are shown in Table 1.

[0265] [Example 2] A 9m openable tank equipped with a stirring blade, a supply pipe and a valve for circulating an inert gas in part of the tank, and a vent line (exhaust pipe) on the outlet side. ３ A stainless steel reactor was prepared. Nitrogen was circulated through the reactor at a rate of 0.60 L / hr per 1 L of the reactor for 2 hours to create a nitrogen atmosphere. Then, nitrogen was circulated through the reactor at a rate of 0.35 L / hr per 1 L of the reactor. 1,140 kg of 1-naphthol aralkyl resin (SN495V, product name, manufactured by Nippon Steel Chemical & Material Co., Ltd.) (hydroxy group equivalent: 230 g / eq., hydroxy group equivalent: 4.96 kmol) as a hydroxy-substituted aromatic compound and 752.33 kg of triethylamine (7.44 kmol, an amount equivalent to 1.5 mol per 1 mol of hydroxy groups in the 1-naphthol aralkyl resin) as a basic compound 1 were dissolved in 6,270 kg of dichloromethane as an organic solvent 1 while maintaining a solution temperature of 0°C. This solution was designated Solution 1.

[0266] A mixed liquid (solution 2) of 487.48 kg (7.93 kmol, 1.60 mol relative to 1 mol of hydroxy groups in the 1-naphthol aralkyl resin) of cyanogen chloride as the cyanogen halide, 1,137.46 kg of dichloromethane as the organic solvent 2, 828.28 kg (8.178 kmol, 1.65 mol relative to 1 mol of hydroxy groups in the 1-naphthol aralkyl resin) of 36% hydrochloric acid as the hydrogen halide, and 5,135.31 kg of water was stirred and kept at a liquid temperature of −3 to −1° C., and into this mixed liquid was added the solution 1 obtained above over 240 minutes, thereby obtaining solution 2. Thereafter, while maintaining the liquid temperature at -3 to -1°C, Solution 2 was further stirred for 5 minutes, and then, while maintaining the liquid temperature at -3 to -1°C, Solution 3, prepared by dissolving 200.62 kg (1.98 mol, 0.40 mol per mol of hydroxy groups in the 1-naphthol aralkyl resin) of triethylamine as basic compound 2 in 200.62 kg of dichloromethane as organic solvent 3, was poured into Solution 2 over 60 minutes to obtain Solution 4. Thereafter, while maintaining the liquid temperature at -3 to -1°C, Solution 4 was further stirred for 30 minutes to complete the reaction, thereby obtaining Reaction Solution 1. The pH of the aqueous phase (upper phase) of Reaction Solution 1 was measured using a pH meter (IQ Scientific Instruments, IQ150 (trade name)) and was found to be 0.9.

[0267] Thereafter, the reaction solution 1 was allowed to stand, and the lower organic phase (dichloromethane phase) and the upper aqueous phase were accurately separated at the interface so as not to be mixed with each other. At this time, both phases were transparent.

[0268] The resulting dichloromethane phase was heated and distilled until the bottom liquid temperature reached a maximum of 41°C, at which point cyanogen chloride and dichloromethane were distilled off. Then, fresh dichloromethane equivalent to the distilled mass was added to the substrate. The mixture was then washed five times with 3,000 kg of water. The electrical conductivity of the wastewater after the fifth water wash was measured using a portable EC meter (HI8733N, product name, manufactured by Hanna Instruments) and found to be 10 μS / cm. This electrical conductivity value confirmed that ionic compounds had been sufficiently removed by washing with water.

[0269] The dichloromethane phase after washing with water was concentrated under reduced pressure, and solvent substitution with a 2-butanone solution was repeated five times to obtain 2,477 kg of a 2-butanone solution containing 50 mass % of the target cyanate ester compound (compound represented by formula (17)). The content of a compound having a triazine ring (compound containing a structure represented by formula (18)) in the obtained cyanate ester compound was 1.2 area % in terms of HPLC area percentage, and the peak top temperature was 280°C. These results are shown in Table 1.

[0270] Comparative Example 1 In a 0.3 L glass flask equipped with a stirrer in an open system, 40 g (hydroxy group equivalent: 230 g / eq., hydroxy group equivalent: 0.17 mol) of 1-naphthol aralkyl resin (SN495V, product name, manufactured by Nippon Steel Chemical & Material Co., Ltd.) as a hydroxy-substituted aromatic compound and 26.4 g (0.26 mol, an amount corresponding to 1.5 mol per mol of hydroxy groups in the 1-naphthol aralkyl resin) of triethylamine as basic compound 1 were dissolved in 240 g of dichloromethane as organic solvent 1 while maintaining the solution temperature at 0°C, to obtain Solution 1.

[0271] A mixed liquid (solution 2) of 16.0 g (0.26 mol, 1.50 mol relative to 1 mol of hydroxy groups in the 1-naphthol aralkyl resin) of cyanogen chloride as cyanogen halide, 37.4 g of dichloromethane as organic solvent 2, 26.4 g (0.26 mol, 1.50 mol relative to 1 mol of hydroxy groups in the 1-naphthol aralkyl resin) of 36% hydrochloric acid as hydrogen halide, and 163.8 g of water was stirred and kept at a liquid temperature of −3 to −1° C., and into this mixed liquid was added the solution 1 obtained above over 14 minutes, thereby obtaining solution 2. Thereafter, while maintaining the liquid temperature at -3 to -1°C, Solution 2 was further stirred for 5 minutes, and then, while maintaining the liquid temperature at -3 to -1°C, Solution 3, prepared by dissolving 8.8 g of triethylamine (0.09 mol, 0.50 mol per mol of hydroxy groups in the 1-naphthol aralkyl resin) as basic compound 2 in 8.8 g of dichloromethane as organic solvent 3, was poured into Solution 2 over 3 minutes to obtain Solution 4. Thereafter, while maintaining the liquid temperature at -3 to -1°C, Solution 4 was further stirred for 30 minutes to complete the reaction, thereby obtaining Reaction Solution 1. The pH of the aqueous phase (upper phase) of Reaction Solution 1 was measured using a pH meter (IQ Scientific Instruments, IQ150 (trade name)) and found to be 0.3.

[0272] Thereafter, the reaction solution 1 was allowed to stand, and the lower organic phase (dichloromethane phase) and the upper aqueous phase were accurately separated at the interface so as not to be mixed with each other. At this time, the aqueous phase side was slightly cloudy.

[0273] The resulting dichloromethane phase was heated and distilled until the bottom liquid temperature reached a maximum of 41°C, at which point cyanogen chloride and dichloromethane were distilled off. Then, fresh dichloromethane equivalent to the distilled mass was added to the substrate. The resulting solution was then washed five times with 200 g of water. The electrical conductivity of the wastewater after the fifth water wash was measured using a portable EC meter (HI8733N, product name, manufactured by Hanna Instruments) and found to be 10 μS / cm. This electrical conductivity value confirmed that ionic compounds had been sufficiently removed by washing with water.

[0274] The dichloromethane phase after washing with water was concentrated under reduced pressure, and solvent substitution with 2-butanone solution was repeated five times to obtain 86.0 g of a 2-butanone solution containing 50 mass % of the target cyanate ester compound (compound represented by formula (17)). The content of the compound having a triazine ring (compound containing a structure represented by formula (18)) in the obtained cyanate ester compound was 4.8 area % in terms of HPLC area percentage, and the peak top temperature was 265°C. These results are shown in Table 1.

[0275] Comparative Example 2: A 0.3 L glass flask with a releasable lid and a stirrer was prepared. Air was circulated through the flask at a rate of 1.0 L / hour per 1 L of the container. 40 g of 1-naphthol aralkyl resin (SN495V, product name, manufactured by Nippon Steel Chemical & Material Co., Ltd.) as a hydroxy-substituted aromatic compound (hydroxy group equivalent: 230 g / eq., hydroxy group equivalent: 0.17 mol) and 26.4 g of triethylamine (0.26 mol, an amount equivalent to 1.5 mol per mol of hydroxy groups in the 1-naphthol aralkyl resin) as a basic compound 1 were dissolved in 240 g of dichloromethane as an organic solvent 1 while maintaining a solution temperature of 0°C. This solution was designated Solution 1.

[0276] A mixed liquid (solution 2) of 16.0 g (0.26 mol, 1.50 mol relative to 1 mol of hydroxy groups in the 1-naphthol aralkyl resin) of cyanogen chloride as cyanogen halide, 37.4 g of dichloromethane as organic solvent 2, 26.4 g (0.26 mol, 1.50 mol relative to 1 mol of hydroxy groups in the 1-naphthol aralkyl resin) of 36% hydrochloric acid as hydrogen halide, and 163.8 g of water was stirred and kept at a liquid temperature of −3 to −1° C., and into this mixed liquid was added the solution 1 obtained above over 14 minutes, thereby obtaining solution 2. Thereafter, while maintaining the liquid temperature at -3 to -1°C, Solution 2 was further stirred for 5 minutes, and then, while maintaining the liquid temperature at -3 to -1°C, Solution 3, prepared by dissolving 10.6 g of triethylamine (0.10 mol, 0.60 mol per mol of hydroxy groups in the 1-naphthol aralkyl resin) as basic compound 2 in 10.6 g of dichloromethane as organic solvent 3, was poured into Solution 2 over 4 minutes to obtain Solution 4, while maintaining the liquid temperature at -3 to -1°C. Thereafter, while maintaining the liquid temperature at -3 to -1°C, Solution 4 was further stirred for 30 minutes to complete the reaction, thereby obtaining Reaction Solution 1. The pH of the aqueous phase (upper phase) of Reaction Solution 1 was measured using a pH meter (IQ Scientific Instruments, IQ150 (trade name)) and was found to be 0.3.

[0277] Thereafter, the reaction solution 1 was allowed to stand, and the lower organic phase (dichloromethane phase) and the upper aqueous phase were accurately separated at the interface so as not to be mixed with each other. At this time, the aqueous phase side was slightly cloudy.

[0278] The resulting dichloromethane phase was heated and distilled until the bottom liquid temperature reached a maximum of 41°C, at which point cyanogen chloride and dichloromethane were distilled off. Then, fresh dichloromethane equivalent to the distilled mass was added to the substrate. The resulting solution was then washed five times with 200 g of water. The electrical conductivity of the wastewater after the fifth water wash was measured using a portable EC meter (HI8733N, product name, manufactured by Hanna Instruments) and found to be 10 μS / cm. This electrical conductivity value confirmed that ionic compounds had been sufficiently removed by washing with water.

[0279] The dichloromethane phase after washing with water was concentrated under reduced pressure, and solvent substitution with 2-butanone solution was repeated five times to obtain 85.1 g of a 2-butanone solution containing 50 mass % of the target cyanate ester compound (compound represented by formula (17)). The content of a compound having a triazine ring (compound containing a structure represented by formula (18)) in the obtained cyanate ester compound was 5.0 area % in terms of HPLC area percentage, and the peak top temperature was 263°C. These results are shown in Table 1.

[0280]

[0281] This application claims priority based on a Japanese patent application (Patent Application No. 2023-122171) filed with the Japan Patent Office on July 27, 2023, the contents of which are incorporated herein by reference.

[0282] The cyanate ester compound of the present invention can be suitably used for, for example, cured products, prepregs, laminates, metal foil-clad laminates, multilayer plates, sealing materials, fiber-reinforced composite materials, adhesives, resin composite sheets, films, and printed wiring boards.

Claims

DEPCT6919 / 02 / 25691.Cyanate ester compounds are present in molecules with two or more cyanate groups, where the amount of the compound containing the triazine ring is 4.0% by area or less by percentage by area from HPLC.2.Cyanate ester compounds according to claim 1, where the cyanate ester compound is represented by the following formula(1) or by the following formula(2):(chemical formula)(1)where each independent Ar1 represents an aromatic ring, each independent Ra represents a hydrogen atom, an alkyl group containing one or more carbon atoms and 6 atoms or fewer, alkenyl groups with 2 or more carbon atoms and 6 or fewer, aryl groups with 6 or more carbon atoms and 12 or fewer, or alkoxy groups with 1 or more carbon atoms and 4 or fewer, a represents the number of cyanate groups bonded to Ar1, and each independent represents an integer of 1 or more and 3 or less, b represents the number of Ra groups bonded to Ar1, and each independent represents the number considered, determined by subtracting (a+2) from the number of substituted subtrahends in Ar1c, which is an integer of 1 or more and 50 or less.and each X independently represents a single bond, an organic two-valence group with one or more carbon atoms and 50 or fewer carbon atoms in which the hydrogen atom may or may not be replaced by a heteroatom, an organic two-valence group with one or more nitrogen atoms and 10 or fewer carbon atoms, a carbonyl group, a carboxylic group, a carbonyl dioxide group, a sulfonyl group, a two-valence sulfur atom, or a two-valence oxygen atom, and where (chemical formula)(2)Ar2 represents the aromatic ring, each Rb independently represents a hydrogen atom, an alkyl group with one or more carbon atoms and 6 or fewer carbon atoms, an alkynyl group with two or more carbon atoms and 6 or fewer carbon atoms, an aryl group with 6 or more carbon atoms and 12 or fewer carbon atoms, or an alkoxy group with one or more carbon atoms and 4 or fewer carbon atoms, d represents the number of cyanate groups bonded to Ar2 and is an integer of 2 or more and 3 or less,and e represents the number of Rb bonded to Ar2 and represents the number considered to be determined by subtracting (d+2) from the number of substituents that can replace in Ar23. Cyanate ester compounds according to claim 2, where each X in formula (1) independently is chosen from a group consisting of two valence organic groups with 1 or more carbon atoms and 50 or fewer carbon atoms, where these two valence organic groups are represented by the following formula (3):(chemical formula)(3), where each Ar3 independently represents an aromatic ring, Rc, Rd, Rg, and Rh each Re and Rf independently represent hydrogen atoms, alkyl groups with one or more carbon atoms and six or fewer carbon atoms, or aryl groups with six or more carbon atoms and twelve or fewer carbon atoms; Re and Rf independently represent hydrogen atoms, alkyl groups with one or more carbon atoms and six or fewer carbon atoms, aryl groups with six or more carbon atoms and twelve or fewer carbon atoms, or alkoxy groups with one or more carbon atoms and four or fewer carbon atoms; and f represents the integer 0 or greater and 5 or less.Organic valence groups with one or more carbon atoms and five or fewer carbon atoms are represented by the following formula(4):(chemical formula)(4), where each independent Ar4 represents an aromatic ring, each independent Ri and Rj represents a hydrogen atom, alkyl groups with one or more carbon atoms and six or fewer carbon atoms, aryl groups with six or more carbon atoms and twelve or fewer carbon atoms, or alkoxy groups with one or more carbon atoms and four or fewer carbon atoms, and g represents the integer 0 or greater and 5 or less, and organic valence groups. Cyanate ester compounds according to claim 1 where the cyanate ester compound is represented by the following formulas (5) through (14): (chemical formulas) where each h in formula (8) represents the integer 4 or more and 7 or less, and each Rk in formula (13) independently represents a hydrogen atom or an alkyl group with 1 or more carbon atoms and 6 or less.

4. Cyanate ester compounds according to claim 1 where the cyanate ester compound is represented by the following formulas (15) or by the following formulas (16): (chemical formulas) (15) where each Ar5 independently represents the aromatic ring, each Rl independently represents the methylene group, methylene oxy group,Methylene oxymethylene groups, or oxymethylene groups, or two or more of these groups connected together, each Rm and Rn independently representing hydrogen atoms, alkyl groups with 1 or more carbon atoms and 6 or fewer carbon atoms, aryl groups with 6 or more carbon atoms and 12 or fewer carbon atoms, or alkoxy groups with 1 or more carbon atoms and 4 or fewer carbon atoms, i representing the number of cyanate groups bonded to Ar5 and each independently representing the integer 1 or more and 3 or less, j representing the number of Rm groups bonded to Ar5 and representing the number considered to be determined by subtracting (i+2) from The number of substituents that can be replaced in Ar5, k represents the number of Rn bonded to Ar5 and represents the number considered to be determined by subtracting 2 from the number of substituents that can be replaced in Ar5, l represents an integer of 1 or more, m represents an integer of 1 or more, and each repeating unit is arranged as chosen, and (chemical formula)(16) where each individual Ar6 represents an aromatic ring, each individual Ro represents a methylene group, methylene oxy group, methylene oxymethylene group, or oxymethylene group, or two or more of these groups connected, each individual Rp and Rq represent a hydrogen atom,Alkyl groups with 1 or more carbon atoms and 6 or fewer carbon atoms, aryl groups with 6 or more carbon atoms and 12 or fewer carbon atoms, or alkoxy groups with 1 or more carbon atoms and 4 or fewer carbon atoms; n represents the number of cyanate groups bonded to Ar6 and is an integer of 2 or more and 3 or less; o represents the number of Rp bonded to Ar6 and represents the number determined by subtracting (n+2) from the number of replaceable substituents in Ar6; p represents the number of Rq bonded to Ar6 and represents the number determined by subtracting 2 from the number of replaceable substituents in Ar6.and i represents an integer of 1 or greater.

5. Cyanate ester compounds according to claim 1, where the cyanate ester compounds are compounds represented by the following formula (17): (chemical formula) (17), where n represents an integer of 1 or greater and 50 or less.

6. Cyanate ester compounds according to claim 1, where the compounds containing the triazine ring are compounds represented by the following structure (18): (chemical formula) (18), where * represents the binding site.

7. Method for the production of cyanate ester compounds according to claim 1, which includes: a precursor solution preparation step, in which a first solution containing an aromatic compound replaced by a hydroxyl group, a base compound, and an organic solvent are prepared in a container, in which the first solution is prepared while an inert gas is circulated at 0.1 L / h or greater and 20 L / h or less per liter of container; a cyano-substitution step, in which the first solution is brought into contact with a second solution containing cyanogen halide, hydrogen halide, an organic solvent, and water,8. Method for producing cyanate ester compounds according to claim 7 where, in the preparation of the starting solution, the temperature of the first solution is 5.0 degrees Celsius or lower.

9. Method for producing cyanate ester compounds according to claim 7 where the cyanate addition step involves bringing the first solution into contact with the second solution to obtain the reaction liquid, and then pouring the third solution containing a base and an organic solvent into the reaction liquid.

10. Method for producing cyanate ester compounds according to claim 7 where, in the cyanate addition step,The amount of starting material added for cyanogen halide is 0.5 mol or more and 5.0 mol or less compared to 1 mol of hydroxyl group of aromatic compound substituted with a hydroxyl group.

11. Method for producing cyanate ester compounds according to claim 7, where in the cyanogen addition step the temperature of the reaction fluid is 5.0 °C or lower.

12. Resin composite containing cyanate ester compounds according to claim 11.

3. Cured product obtained by curing the resin composite according to claim 12.