JP2019034995A - Thermosetting resin composition and resin cured product - Google Patents

Abstract

To provide a thermosetting resin composition that is a mixed resin composition including a benzoxazine compound and an epoxy compound and can enhance heat resistance and moisture resistance of a cured product of the resin composition and to provide a resin cured product produced by curing the thermosetting resin composition.SOLUTION: The thermosetting resin composition includes (A) a benzoxazine compound, (B) an epoxy compound and (C) a polycarbodiimide compound. Alternatively, the thermosetting resin composition further includes (D) an imidazole compound. The resin cured product is produced by curing either of these thermosetting resin compositions.SELECTED DRAWING: None

Description

  The present invention relates to a thermosetting resin composition of a mixed system of a benzoxazine compound and an epoxy compound, and a resin cured product that is a cured product thereof.

The benzoxazine compound generates a phenolic hydroxyl group by opening the oxazine ring and polymerizes to produce a benzoxazine resin. For this reason, benzoxazine resin is a thermosetting resin having heat resistance and flame retardancy similar to those of conventional phenol resins, and is excellent in electrical insulation, dimensional stability, etc., and does not generate by-product gas. It has the features of Because of such excellent features, the benzoxazine resin is expected to be applied to uses such as a printed circuit board, an adhesive, and a matrix resin of a fiber-reinforced composite material.
Furthermore, a cured product of a mixed resin composition in which a benzoxazine compound and an epoxy compound are used in combination is also known from the viewpoint of improving the thermal characteristics and processability of the benzoxazine resin.

A mixed resin composition of a benzoxazine compound and an epoxy compound has a problem that high temperature and long time curing conditions are required for thermosetting, and a curing catalyst is usually used to accelerate the curing reaction.
In the curing reaction of the mixed resin composition, when a general-purpose curing catalyst for epoxy resin or a curing catalyst such as para-toluenesulfonic acid or imidazole compound usually used for curing a benzoxazine compound is used, an epoxy compound It is easy to prioritize the curing reaction between them, it becomes difficult to produce a cured product of a benzoxazine compound and an epoxy compound, and it is difficult to improve the thermal characteristics.

Further, as a curing catalyst for the curing reaction of the mixed resin composition, for example, Patent Document 1 describes that high heat resistance can be obtained by using a boron trifluoride amine complex.
Patent Document 2 describes that by using a rare earth metal salt as a curing catalyst, curing can proceed sufficiently at a low curing temperature.
Further, Patent Document 3 discloses that toluene sulfonate ester and benzene sulfonate ester are not only a reaction between a phenolic hydroxyl group generated by ring opening of an oxazine ring of a benzoxazine compound and an epoxy group, but also an oxazine ring of a benzoxazine compound. It is described that the ring-opening reaction of can also be promoted.

JP 2010-254895 A JP-A-2006-47903 JP-T-2015-522092

  Although it is considered that the curing catalyst described in the above Patent Documents 1 to 3 can promote the ring-opening reaction of the oxazine ring of the benzoxazine compound, it is not necessarily generated by the opening of the oxazine ring of the benzoxazine compound. The phenolic hydroxyl group and the epoxy group coexisting with the phenolic hydroxyl group do not always have a polymerization promoting action. For this reason, it cannot be said that the produced | generated hardened | cured material is a hardened | cured material provided with sufficient heat resistance and moisture resistance.

  Under such circumstances, the present inventors have found that various physical properties of a cured product are improved by applying a polycarbodiimide compound as a curing agent in a mixed resin composition of a benzoxazine compound and an epoxy compound. .

  The present invention has been made on the basis of the above knowledge, and in a mixed resin composition containing a benzoxazine compound and an epoxy compound, thermosetting capable of improving the heat resistance and moisture resistance of a cured product of the resin composition. An object of the present invention is to provide a functional resin composition and a cured resin product obtained by curing the same.

  The present invention is based on the finding that by adding a polycarbodiimide compound to a mixed resin composition of a benzoxazine compound and an epoxy compound, the heat resistance and moisture resistance of the cured product of the resin composition are improved. It is.

That is, the present invention provides the following [1] to [6].
[1] A thermosetting resin composition containing a benzoxazine compound (A), an epoxy compound (B), and a polycarbodiimide compound (C).
[2] The thermosetting resin composition according to [1], further including an imidazole compound (D).
[3] The above [2], wherein the content of the imidazole compound (D) is 0.1 to 10 parts by mass with respect to 100 parts by mass in total of the benzoxazine compound (A) and the epoxy compound (B). The thermosetting resin composition described in 1.
[4] The above [1], wherein the content of the polycarbodiimide compound (C) is 0.1 to 30 parts by mass with respect to 100 parts by mass in total of the benzoxazine compound (A) and the epoxy compound (B). ] The thermosetting resin composition of any one of [3].
[5] The ratio (N ₂ / N ₁ ) of the total number N ₂ of epoxy groups of the epoxy compound (B) to the total number N ₁ of oxazine rings of the benzoxazine compound (A) is 0.5 to 1.5. The thermosetting resin composition according to any one of [1] to [4] above.
[6] A cured resin product obtained by curing the thermosetting resin composition according to any one of [1] to [5].

The thermosetting resin composition of the present invention can improve the heat resistance and moisture resistance of the cured product in a mixed resin composition of a benzoxazine compound and an epoxy compound.
Therefore, the cured resin obtained by curing the resin composition can be suitably applied to uses such as a printed circuit board, an adhesive, and a matrix resin of a fiber reinforced composite material.

  Hereinafter, the thermosetting resin composition of the present invention and the cured resin that is a cured product thereof will be described in detail.

[Thermosetting resin composition]
The thermosetting resin composition of the present invention (hereinafter also simply referred to as “resin composition”) includes a benzoxazine compound (A), an epoxy compound (B), and a polycarbodiimide compound (C).
The thermosetting resin composition is a mixed resin composition of a benzoxazine compound (A) and an epoxy compound (B), in which a polycarbodiimide compound (C) is blended, and the polycarbodiimide compound (C) Plays a role as a curing agent. By using the polycarbodiimide compound (C), the heat resistance and moisture resistance of the cured product of the resin composition can be improved.

In addition to the benzoxazine compound (A), the epoxy compound (B), and the polycarbodiimide compound (C), the thermosetting resin composition may contain an imidazole compound (D) to be described later and other additive components. Good.
When the thermosetting resin composition is mainly composed of a benzoxazine compound (A), an epoxy compound (B), and a polycarbodiimide compound (C), a viewpoint of obtaining a resin cured product having sufficient heat resistance and moisture resistance Therefore, the total content of the main components in the resin composition is preferably 90% by mass or more, more preferably 95% by mass or more, and still more preferably 98% by mass or more.
In addition, as the other additive component, when the resin composition includes an inorganic filler such as a powder filler described later, the inorganic filler or the like may be a main component. In this case, the total content of the benzoxazine compound (A), the epoxy compound (B) and the polycarbodiimide compound (C) in the resin composition is preferably 5% by mass or more, more preferably 8% by mass or more. More preferably, it is 10% by mass or more.

(Benzoxazine compound (A))
The benzoxazine compound (A) is a compound having a benzoxazine ring that is one type of oxazine ring. A benzoxazine compound (A) may be used individually by 1 type, and may use 2 or more types together. The content of the benzoxazine compound (A) in a total of 100 parts by mass of the benzoxazine compound (A), the epoxy compound (B) and the polycarbodiimide compound (C) is sufficient heat resistance of the cured product of the thermosetting resin composition. From the viewpoints of heat resistance and moisture resistance, it is preferably 30 to 80 parts by mass, and more preferably 40 to 70 parts by mass.

  As a benzoxazine compound (A), the compound which has group represented by following formula (1) is mentioned, for example.

In the formula (1), R ¹ is an alkyl group, an aryl group or an aryl group having a substituent, and represents a substituent bonded to the benzene ring in the benzoxazine ring. n represents the number of R ¹ bonded to the benzene ring, and is an integer of 0 to 3, preferably 0 or 1. When R ¹ is plural, the plural R ¹ may be the same as or different from each other.
In addition, * means that it is a predetermined group or two benzoxazine rings are connected via a predetermined group, as will be described later.

The alkyl group may be linear, branched or cyclic, and preferably has 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms. Examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a cyclopentyl group, and a cyclohexyl group.
The aryl group preferably has 6 to 20 carbon atoms, and more preferably has 6 to 14 carbon atoms. For example, a phenyl group, 1-naphthyl group, 2-naphthyl group, phenanthryl group, biphenyl group and the like can be mentioned.
In the aryl group having the substituent (hereinafter also referred to as “substituted aryl group”), the aryl group excluding the substituent preferably has 6 to 20 carbon atoms, more preferably 6 to 14 carbon atoms. Examples of the substituent include an alkyl group and a halogen atom, and part or all of the hydrogen atoms of the aryl group are substituted by the substituent. Examples of the substituted aryl group include o-tolyl group, m-tolyl group, p-tolyl group, xylyl group, o-ethylphenyl group, m-ethylphenyl group, p-ethylphenyl group, o-tert-butyl. A phenyl group, m-tert-butylphenyl group, p-tert-butylphenyl group, o-chlorophenyl group, o-bromophenyl group and the like can be mentioned.

  Examples of the benzoxazine compound (A) include compounds represented by the following formula (1-1).

In formula (1-1), R ² and R ³ are each independently an alkyl group, an aryl group, or an aryl group having a substituent. R ³ represents a substituent bonded to the benzene ring in the benzoxazine ring. m represents the number of R < ³ > couple | bonded with the said benzene ring, is an integer of 0-4, Preferably it is an integer of 0-2, More preferably, it is 0 or 1. When R ³ is plural, R ³ may be the same or different from each other.

The alkyl group, aryl group and substituted aryl group for R ² and R ³ may be the same as the alkyl group, aryl group and substituted aryl group for R ¹ described above, respectively. From the viewpoint of ease of handling, R ² is preferably a methyl group, an ethyl group, a propyl group, a phenyl group or an o-methylphenyl group.

  Moreover, as a benzoxazine compound (A), the compound represented by following formula (1-2) is mentioned.

In Formula (1-2), R ⁴ and R ⁵ are each independently an alkyl group, an aryl group, or a substituted aryl group, and represent a substituent that is bonded to a benzene ring in a benzoxazine ring. L ¹ is a divalent group that connects the nitrogen atoms of two benzoxazine rings. p and q each independently represent the number of R ⁴ and R ⁵ bonded to the benzene ring, and are an integer of 0 to 4, preferably an integer of 0 to 2, more preferably 0 or 1. When R ⁴ is a plurality, the plurality of R ⁴ may be the same or different from each other. Further, when R ⁵ is plural, the plurality of R ⁵ may be the same or different.

The alkyl group, aryl group and substituted aryl group for R ⁴ and R ⁵ may be the same as the alkyl group, aryl group and substituted aryl group for R ¹ described above, respectively.

Examples of the divalent group in L ¹ include a group containing an alkanediyl group and / or an arylene group. In addition, a group composed of a combination of one kind or two or more kinds of alkanediyl group and arylene group, and further a group containing a carbonyl group, an oxygen atom, a sulfur atom, a thiocarbonyl group, a sulfonyl group, etc. There may be.
The alkanediyl group preferably has 1 to 20 carbon atoms, and more preferably has 1 to 14 carbon atoms. For example, a methylene group, ethylene group, ethane-1,1-diyl group, propane-1,3-diyl group, propane-2,2-diyl group, propane-1,2-diyl group and the like can be mentioned.
The arylene group preferably has 1 to 20 carbon atoms, and more preferably has 1 to 14 carbon atoms. For example, a phenylene group, a naphthylene group, etc. are mentioned.
Examples of such a group include groups represented by the following formulas (L-1) to (L-5).

Among these, from the viewpoint of ease of handling, L ¹ is a methylene group, a propane-2,2-diyl group, a phenylene group, or a formula (L-1), (L-2) or (L-3). The group represented by these is preferable.

  Moreover, as a benzoxazine compound (A), the compound represented by following formula (1-3) is mentioned.

In Formula (1-3), R ^{6 to} R ⁹ are each independently an alkyl group, an aryl group, or a substituted aryl group, and R ⁸ and R ⁹ are a substituent bonded to a benzene ring in a benzoxazine ring. Represents a group. L ² is an atom that forms a direct bond, a divalent group, or a divalent anion that connects the benzene rings of the two benzoxazine rings. r and s each independently represent the number of R ⁸ and R ⁹ bonded to the benzene ring, and are integers of 0 to 3, preferably 0 or 1. When R ⁸ is plural, a plurality of R ⁸ may be the same or different from each other. When R ⁹ is plural, the plural R ⁹ may be the same or different from each other.

The alkyl group, aryl group and substituted aryl group in R ^{6 to} R ⁹ may be the same as the alkyl group, aryl group and substituted aryl group in R ¹ described above, respectively. From the viewpoint of easy handling, R ⁶ and R ⁷ are preferably a methyl group, an ethyl group, a propyl group, a phenyl group, or an o-methylphenyl group.

Examples of L ² include a direct bond, an alkanediyl group, an arylene group, an alkanediyl group and / or an arylene group, a carbonyl group, an oxygen atom, a sulfur atom, a thiocarbonyl group, a sulfonyl group, and the like. Can be mentioned. It may be the same as the group constituted by combining the alkanediyl group, the arylene group, and the alkanediyl group and / or the arylene group in L ² .

  Specific examples of the benzoxazine compound (A) are shown below. In the following formulae, Ph represents a phenyl group.

  As the benzoxazine compound (A), in addition to the above, an oligomer obtained by polymerizing several molecules of the compound, a compound obtained by further modifying the compound, and the like can be suitably used.

  As a commercial item of the benzoxazine compound (A), for example, “Fa type” shown in the following formula (1-a), “Pd type” shown in the following formula (1-b) (both are Shikoku Chemicals) Kogyo Co., Ltd.).

(Epoxy compound (B))
The epoxy compound (B) is a compound having an epoxy group. The epoxy compound (B) can react with a phenolic hydroxyl group produced by ring opening of the oxazine ring of the benzoxazine compound (A). For this reason, by setting it as the resin composition of the mixed system of a benzoxazine compound (A) and an epoxy compound (B), the heat resistance of the hardened | cured material of a resin composition rather than the resin composition of only a benzoxazine compound (A). It is considered that the property, workability, anti-softening property at high temperature, etc. can be improved.

The content of the epoxy compound (B) in the thermosetting resin composition is the total number N _{1 of} oxazine rings of the benzoxazine compound (A) from the viewpoint of heat resistance and processability of the cured product of the resin composition. It is preferable that the ratio (N ₂ / N ₁ ) of the total number N ₂ of epoxy groups of the epoxy compound (B) with respect to is 0.5 to 1.5, more preferably 0.7 to 1. 3, more preferably 0.9 to 1.1.
The mass ratio of the epoxy compound (B) content in the thermosetting resin composition is preferably 10 to 200 parts by mass, more preferably 100 parts by mass of the benzoxazine compound (A). It is 20-180 mass parts, More preferably, it is 30-160 mass parts.

  As the epoxy compound (B), for example, a compound having a glycidyl group, a compound having an alicyclic epoxy group, and the like are suitably used.

The epoxy compound (B) may be a compound having one epoxy group or a compound having two or more from the viewpoint of easy formation of a crosslinked structure.
Examples of the compound having one epoxy group include phenyl glycidyl ether, 7-oxabicyclo [4.1.0] heptane-3-carboxylic acid hexyl ester, 2-ethylhexyl glycidyl ether, and allyl glycidyl ether.
Examples of the compound having two or more epoxy groups include phenols, amines, carboxylic acids, and epoxy compounds prepared using a compound having an unsaturated carbon bond as a precursor.

  Examples of epoxy compounds having phenols as precursors include bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, resorcinol diglycidyl ether, bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol. S type epoxy resin, epoxy resin having biphenyl skeleton, phenol novolac type epoxy resin, cresol novolac type epoxy resin, resorcinol type epoxy resin, epoxy resin having naphthalene skeleton, trisphenylmethane type epoxy resin, phenol aralkyl type epoxy resin, di Examples thereof include cyclopentadiene type epoxy resins and diphenylfluorene type epoxy resins. In addition, various isomers, alkyl groups, halogen-substituted ones, and the like can also be used. Moreover, the epoxy resin which modified these with the urethane compound and the isocyanate compound can also be used.

  Examples of the epoxy compound having amines as a precursor include tetraglycidyldiaminodiphenylmethane, a glycidyl compound of xylenediamine, triglycidylaminophenol, and glycidylaniline. Moreover, the substituted body by these alkyl groups, a halogen atom, etc. can also be used.

  Examples of the epoxy compound having a carboxylic acid as a precursor include glycidyl esters of carboxylic acids such as phthalic acid, hexahydrophthalic acid, and dimer acid.

  As an epoxy compound which makes a precursor the compound which has an unsaturated carbon bond, an alicyclic epoxy compound is mentioned, for example. Examples of the alicyclic epoxy compound include (3 ′, 4′-epoxycyclohexane) methyl-3,4-epoxycyclohexanecarboxylate, (3 ′, 4′-epoxycyclohexane) octyl-3,4-epoxycyclohexanecarboxyl. Rate, 1-methyl-4- (2-methyloxiranyl) -7-oxabicyclo [4.1.0] heptane, and the like.

(Polycarbodiimide compound (C))
A polycarbodiimide compound is a compound having two or more carbodiimide groups.
By blending the polycarbodiimide compound (C) into a mixed resin composition of the benzoxazine compound (A) and the epoxy compound (B), the polycarbodiimide compound (C) exhibits an excellent action as a curing agent. The polycarbodiimide compound (C) has a crosslinking reactivity with respect to the alcoholic hydroxyl group generated by the ring opening of the epoxy group of the epoxy compound (B), and also reacts with the phenolic hydroxyl group generated by the ring opening of the oxazine ring. . For this reason, a polycarbodiimide compound (C) can accelerate | stimulate hardening of a resin composition, can raise a glass transition temperature, and can improve heat resistance. Further, the carbodiimide group also reacts with a hydroxyl group generated by the reaction between an epoxy group and a phenolic hydroxyl group, whereby the water absorption of the cured product is lowered and the moisture resistance can be improved.

  The content of the polycarbodiimide compound (C) in the thermosetting resin composition is based on 100 parts by mass in total of the benzoxazine compound (A) and the epoxy compound (B) from the viewpoint of improving heat resistance and moisture resistance. It is preferable that it is 0.1-30 mass parts, More preferably, it is 0.5-25 mass parts, More preferably, it is 1-20 mass parts.

The polycarbodiimide compound (C) can be obtained by a decarboxylation condensation reaction of a diisocyanate compound using a known synthesis method.
The diisocyanate compound is not particularly limited, and may be a chain or alicyclic aliphatic diisocyanate compound, an aromatic diisocyanate compound, or a heterocyclic diisocyanate compound. Two or more kinds may be used in combination. Specifically, chain aliphatic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate; 1,4-bis (isocyanatomethyl) cyclohexane, 2,2 -Alicyclic diisocyanates such as bis (4-isocyanatocyclohexyl) propane, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate; including aromatic rings such as 1,3-bis (2-isocyanato-2-propyl) benzene Aliphatic diisocyanate; toluene-2,4-diisocyanate, 2,2′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4 , 6-triisopropylbenzene-1,3-diyl diisocyanate and the like.

As the polycarbodiimide compound (C), from the viewpoint of stability and the like, the polycarbodiimide compound having an isocyanate group at the terminal obtained by the decarboxylation condensation reaction is a known terminal having a group having reactivity with the isocyanate group. It is preferable to react with a sealing agent to seal the terminal isocyanate group. Examples of the substituent include a hydroxyl group, a carboxyl group, an amino group, and an isocyanate group. Specific examples include cyclohexyl monoisocyanate, which is a monoisocyanate compound.
Moreover, as a polycarbodiimide compound (C), commercial items, such as "carbodilite" (made by Nisshinbo Chemical Co., Ltd.), can also be used, for example.

(Imidazole compound (D))
The thermosetting resin composition may further contain an imidazole compound (D).
The imidazole compound (D) acts as a curing catalyst (curing accelerator) that accelerates the curing reaction of the benzoxazine compound (A) and the epoxy compound (B). Even if only the combined use of the mixed resin composition of the benzoxazine compound (A) and the epoxy compound (B) and the carbodiimide compound is used, the curing reaction is sufficiently accelerated. Can be promoted.

  The content of the imidazole compound (D) in the thermosetting resin composition may be a normal catalytic amount as a curing catalyst, and is 0 with respect to 100 parts by mass in total of the benzoxazine compound (A) and the epoxy compound (B). It is preferable that it is 1-10 mass parts, More preferably, it is 0.2-8 mass parts, More preferably, it is 0.3-5 mass parts.

  As the imidazole compound (D), a known catalyst for curing an epoxy resin can be used. For example, imidazole, 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-ethyl-4- Methylimidazole (abbreviation “2E4MZ”), 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-hydroxyimidazole, 2 , 3-dihydro-1H-pyrrolo [1,2-a] benzimidazole and the like. These may be used alone or in combination of two or more.

In general, the curing catalysis by the imidazole compound (D) tends to give priority to the curing reaction between the epoxy compounds (B), but depending on the type, the oxidative ring opening of the benzoxazine compound (A) occurred. It may act on a phenolic hydroxyl group, or may act on the opening of the oxazine ring, and may act on these multiple processes.
For example, 2-ethyl-4-methylimidazole (2E4MZ), which is a general-purpose imidazole compound, acts mainly on the epoxy group and the opening of the oxazine ring of the benzoxazine compound (A). 2,3-Dihydro-1H-pyrrolo [1,2-a] benzimidazole having a skeleton mainly has an action on the reaction between a phenolic hydroxyl group and an epoxy group and an action on the opening of an oxazine ring. It is considered a thing.

(Other ingredients)
The thermosetting resin composition may contain other components other than those described above, if necessary, depending on the purpose of use and application. The thermosetting resin composition may contain, for example, a maleimide resin, a cyanate ester resin, or the like. Moreover, the thermosetting resin composition may contain an inorganic filler for the purpose of further imparting characteristics such as a low thermal expansion coefficient and high thermal conductivity to the cured product. Examples of the inorganic filler include various powder fillers such as silica, alumina, silicon nitride, boron nitride, silicon carbide, and aluminum nitride. In addition, for example, various additives such as a solvent, a colorant, a dispersant, an ultraviolet absorber, and an antioxidant may be included.

  The thermosetting resin composition can be obtained by mixing and stirring the benzoxazine compound (A), the epoxy compound (B), and the polycarbodiimide compound (C). A known method can be applied to the mixing and stirring method. Furthermore, you may add the other component mentioned above as an arbitrary component as an imidazole compound (D) as needed. The order of adding and mixing the components is not particularly limited. In the case of mixing and stirring, a solvent may be appropriately used from the viewpoint of uniformly mixing each compounding component.

In the thermosetting resin composition, a bismaleimide compound (B ′) can be used in place of the epoxy compound (B) or together with the epoxy compound (B). The cured product of the resin composition containing the benzoxazine compound (A), the bismaleimide compound (B ′) and the polycarbodiimide compound (C) also has the same characteristics as the cured product of the thermosetting resin composition, It can be applied to similar uses.
The bismaleimide compound (B ′) is a compound having two maleimide rings. In the bismaleimide compound (B ′), the double bond between carbon atoms constituting the ring of the maleimide ring reacts with a phenolic hydroxyl group generated by the opening of the oxazine ring of the benzoxazine compound (A). For this reason, even in the mixed resin composition of the benzoxazine compound (A) and the bismaleimide compound (B ′), as in the thermosetting resin composition, heat resistance, workability, anti-softening property at high temperature, etc. A cured product excellent in the above can be obtained.
In such a mixed resin composition of the benzoxazine compound (A) and the bismaleimide compound (B ′), the polycarbodiimide compound (C) exhibits an excellent action as a curing agent. That is, even in the mixed resin composition of the benzoxazine compound (A) and the bismaleimide compound (B ′), by using the polycarbodiimide compound (C), curing of the resin composition is accelerated, and heat resistance and moisture resistance are increased. Can be improved.

  The bismaleimide compound (B ′) is not particularly limited. For example, N, N′-ethylene bismaleimide, N, N′-tetramethylene bismaleimide, N, N′-hexamethylene bismaleimide, N , N′-1,3-phenylenebismaleimide, N, N′-1,4-phenylenebismaleimide, 4,4′-bismaleimide diphenylmethane, bis (3-ethyl-5-methyl-4-maleimidophenyl) methane Bisphenol A bis (4-maleimidophenyl ether), N, N′-4,4′-diphenylsulfone bismaleimide and the like. These may be used alone or in combination of two or more.

  The resin composition containing the benzoxazine compound (A), the bismaleimide compound (B ′) and the polycarbodiimide compound (C) may further contain an imidazole compound (D). The imidazole compound (D) also acts as a curing catalyst (curing accelerator) that accelerates the curing reaction between the benzoxazine compound (A) and the bismaleimide compound (B ′) in the resin composition. It can be used similarly to the thermosetting resin composition.

[Resin cured product]
The cured resin of the present invention is a reaction product obtained by curing the thermosetting resin composition. The resin cured product is obtained by heating and reacting the thermosetting resin composition.
The thermosetting resin composition can be cured, for example, by heating at 120 to 250 ° C, preferably 140 to 230 ° C, more preferably 140 to 220 ° C. The curing time may be, for example, 10 minutes to 10 hours, and may be 30 minutes to 5 hours. In the heating process, from the viewpoint of obtaining a homogeneous cured resin product, pre-curing at a temperature slightly lower than the curing temperature of the cured resin material, followed by curing at a higher temperature for a longer time, curing by stepwise heat treatment It is preferable that it is a process.

The resin cured product is excellent in heat resistance and moisture resistance due to the use of the polycarbodiimide compound (C) as a curing agent, and the curing reaction time is shortened, whereby the benzoxazine compound (A) and the epoxy compound ( It becomes possible to efficiently produce the mixed resin cured product of B).
As described above, the cured resin is excellent in properties such as flame retardancy, mechanical properties, and electrical insulation, and further improved in heat resistance and moisture resistance. It can be suitably applied to uses such as a matrix resin of the material.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by this.
The details of the blending raw materials of the resin compositions used in the following examples and comparative examples are as follows.

<Benzoxazine compound (A)>
・ "Fa type": Shikoku Kasei Kogyo Co., Ltd.

<Epoxy compound (B)>
Bisphenol A diglycidyl ether (DGEBA): Epoxy equivalent 190
<Polycarbodiimide compound (C)>
-Produced by Synthesis Example 1 below <Imidazole Compound (D)>
(D1) 2-ethyl-4-methylimidazole: “2E4MZ”, manufactured by Shikoku Chemicals Co., Ltd. (D2) 2,3-dihydro-1H-pyrrolo [1,2-a] benzimidazole: “TBZ”, Shikoku Chemicals Made by Kogyo Co., Ltd.

(Synthesis Example 1) Synthesis of Polycarbodiimide Compound (C) 100 g of dicyclohexylmethane-4,4′-diisocyanate, 4.8 g of cyclohexyl isocyanate, and 3-methyl-1-phenyl-2-phospholene-1-oxide as a carbodiimidization catalyst 1.0 g was put into a reaction tube equipped with a reflux tube and a stirrer, and reacted at 180 ° C. for 30 hours under a nitrogen stream. Then, it cooled to room temperature and obtained the polycarbodiimide compound (carbodiimide equivalent 217).

[Preparation of thermosetting resin composition]
Example 1
115 parts by mass of the benzoxazine compound (A), 100 parts by mass of the epoxy compound (B), and 10 parts by mass of the polycarbodiimide compound (C) were uniformly stirred and mixed to prepare a thermosetting resin composition (benzoxazine compound ( epoxy compound to the total number N ₁ of oxazine ring of a) (B) epoxy group ratio of the total number N ₂ of _{(N 2 / N 1) =} 1.0).
(Examples 2 and 3)
The compounding amount of the polycarbodiimide compound (C) was changed as shown in Table 1 below, and the other thermosetting resin compositions were obtained in the same manner as in Example 1 except that.
(Comparative Example 1)
A thermosetting resin composition was obtained in the same manner as in Example 1 except that the polycarbodiimide compound (C) was not blended.

Example 4
115 parts by mass of the benzoxazine compound (A), 100 parts by mass of the epoxy compound (B), 10 parts by mass of the polycarbodiimide compound (C), and 1 part by mass of the imidazole compound (D1) are uniformly stirred and mixed to obtain a thermosetting resin composition. A product was prepared.
(Examples 5 and 6)
The compounding amount of the polycarbodiimide compound (C) was changed as shown in Table 2 below, and the other thermosetting resin compositions were obtained in the same manner as in Example 4 except that.
(Comparative Example 2)
A thermosetting resin composition was obtained in the same manner as in Example 4 except that the polycarbodiimide compound (C) was not blended.

(Example 7)
115 parts by mass of the benzoxazine compound (A), 100 parts by mass of the epoxy compound (B), 10 parts by mass of the polycarbodiimide compound (C), and 1 part by mass of the imidazole compound (D2) are uniformly stirred and mixed to form a thermosetting resin composition. A product was prepared.
(Examples 8 and 9)
The compounding amount of the polycarbodiimide compound (C) was changed as shown in Table 2 below, and the other thermosetting resin compositions were obtained in the same manner as in Example 7.
(Comparative Example 3)
A thermosetting resin composition was obtained in the same manner as in Example 7 except that the polycarbodiimide compound (C) was not blended.

[Production of cured resin]
Each thermosetting resin composition obtained in the above Examples and Comparative Examples was heated (precured) at 180 ° C. for 1 hour, and further heated (cured) at 200 ° C. for 2 hours to obtain a cured resin.

[Evaluation of physical properties of cured resin]
About each resin hardened | cured material manufactured above, the glass transition temperature and the water absorption were measured by the method shown below, and physical-property evaluation was performed. The evaluation results are summarized in Tables 1 and 2 below.

(Glass-transition temperature)
A sample piece (10 mm × 20 mm × 0.2 mm) of the cured resin was cut out, and the glass transition temperature was measured with a dynamic viscoelasticity (DMA) measuring device (“DMS6100”, manufactured by Seiko Instruments Inc.). Measurement conditions were set to a temperature increase rate of 10 ° C./min in an air atmosphere.
The glass transition temperature is an index of the heat resistance of the cured resin, and it can be said that the higher the temperature, the better the heat resistance.

(Water absorption rate)
Cut out a specimen (10 mm x 20 mm x 0.2 mm) of the cured resin and measure the water absorption rate with a pressure cooker test device (HAST CHAMBER “EHS-210M”, manufactured by Espec Corporation). did. After measuring the weight W0 of the test piece before water absorption, water was absorbed for 3 hours in an environment of a temperature of 121 ° C., humidity of 100% RH, and atmospheric pressure of 2 atm, and the weight W1 of the sample piece was measured. The rate was calculated.
Water absorption [mass%] = {(W1-W0) / W0} × 100
The water absorption is an index of moisture resistance in the cured resin, and it can be said that the lower the water absorption, the better the moisture resistance.

As can be seen from the results shown in Tables 1 and 2, it was confirmed that the use of the polycarbodiimide compound (C) increased the glass transition temperature of the cured resin as the blending amount increased. Furthermore, it was recognized that glass transition temperature becomes higher by adding imidazole compound (D).
On the other hand, when the imidazole compound (D) was added as a curing catalyst to the benzoxazine compound (A) and the epoxy compound (B) (Comparative Examples 2 and 3), the glass transition temperature increased, but the water absorption increased. (See Comparative Examples 1 to 3).
From the above, it can be said that the cured product of the thermosetting resin composition containing the benzoxazine compound (A), the epoxy compound (B), and the polycarbodiimide compound (C) is excellent in heat resistance and moisture resistance.

Claims (6)

  A thermosetting resin composition comprising a benzoxazine compound (A), an epoxy compound (B), and a polycarbodiimide compound (C).   Furthermore, the thermosetting resin composition of Claim 1 containing an imidazole compound (D).   The heat | fever of Claim 2 whose content of the said imidazole compound (D) is 0.1-10 mass parts with respect to a total of 100 mass parts of the said benzoxazine compound (A) and the said epoxy compound (B). Curable resin composition.   The content of the polycarbodiimide compound (C) is 0.1 to 30 parts by mass with respect to 100 parts by mass in total of the benzoxazine compound (A) and the epoxy compound (B). The thermosetting resin composition according to any one of the above. The ratio (N ₂ / N ₁ ) of the total number N ₂ of epoxy groups that the epoxy compound (B) has to the total number N ₁ of oxazine rings that the benzoxazine compound (A) has is 0.5 to 1.5, The thermosetting resin composition of any one of Claims 1-4.   A cured resin product obtained by curing the thermosetting resin composition according to any one of claims 1 to 5.