JP2010031087A - Impregnating material for fibrous substrate, prepreg and fiber-reinforced composite material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an impregnating material for a fibrous substrate that exhibits excellent impregnating properties when formed into a prepreg as well as an excellent balance among handleability (tack properties), heat resistance and toughness after formed into a prepreg. <P>SOLUTION: The impregnating material for a fibrous substrate comprising an epoxy resin composition for impregnating a fibrous substrate includes: [A] epoxidized polyphenylene ether; [B] an epoxy resin; and [C] a curing agent, where [A] is epoxidized polyphenylene ether having a specific structure. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an impregnating material for a fiber substrate, a prepreg, and a fiber reinforced composite material.

  Epoxy resins are widely used in fields such as encapsulants for electronic materials, paints / coating materials, adhesives and the like because they are excellent in mechanical properties, electrical properties and adhesiveness after curing. Conventionally, in the field of fiber reinforced composite materials (hereinafter also abbreviated as FRP), epoxy is generally used for low shrinkage during curing, moldability, adhesion to fibers, heat resistance of cured products, and strength improvement. Thermosetting resins based on resins are widely used. In particular, from the viewpoint of achieving both workability and heat resistance, bifunctional epoxy resins such as bisphenol A type epoxy resin and bisphenol F type epoxy resin, and polyfunctionals such as phenol novolac epoxy resin, cresol novolac epoxy resin, tetraglycidyl diaminodiphenylmethane, etc. Resin compositions combining thermoplastic resins such as epoxy resins and phenoxy resins are widely used.

In recent years, there has been a demand for higher functionality such as further strengthening, higher heat resistance, and weight reduction of FRP. In order to satisfy this requirement, for example, as in Patent Document 1, an attempt is made to achieve both toughness and heat resistance by using a tolylene diisocyanate-modified epoxy resin of a bisphenol A type epoxy resin. Patent Document 2 describes an epoxy resin composition containing an acrylonitrile-butadiene copolymer as an additive. Patent Document 3 describes an epoxy resin composition containing a thermoplastic resin in the resin composition.
International Publication No. 98/44017 Pamphlet WO 97/28210 pamphlet JP 2006-219513 A

However, the modified epoxy resin used in Patent Document 1 increases the blending amount of a lower viscosity epoxy resin, for example, bisphenol A type liquid epoxy resin or bisphenol F type liquid epoxy resin, to increase the viscosity of the epoxy resin composition. Since it needs to be lowered, it tends to be difficult to maintain sufficient heat resistance as a cured product characteristic.
Moreover, like the epoxy resin composition of the said patent document 2 and the patent document 3, when an acrylonitrile-butadiene copolymer and a thermoplastic resin are used together as an additive, even if it is compatible with an epoxy resin, the resin composition The increase in melt viscosity is increased, fluidity is impaired, and it tends to be difficult to produce a prepreg uniformly impregnated with resin. If the resin is not uniformly impregnated in the prepreg, voids are generated when it is semi-cured, resulting in poor appearance of the resulting semi-cured product and reduced adhesion to other prepregs. However, there is still room for improvement.
This invention is made | formed in view of this subject, and it aims at providing the impregnation material for fiber base materials excellent in the handleability after prepreg, heat resistance, and toughness balance.

In order to solve the above-mentioned problems, the present inventor has conducted extensive research focusing on the relationship between the properties of the modified epoxy resin obtained by modification and the properties of the cured product, and as a result, epoxidized polyphenylene having a specific skeleton has been obtained. It has been found that an impregnating material for a fiber base material composed of an epoxy resin composition containing ether is excellent in the balance of handleability after being prepreg, heat resistance and toughness, and has made the present invention.
That is, the present invention is as follows.
[1]
For fiber base materials comprising an epoxy resin composition comprising an epoxidized polyphenylene ether [A], an epoxy resin [B], and a curing agent [C], wherein the [A] has a structure represented by the following general formula (1) Impregnating material.

(In the formula, A is a hydrogen atom or the following general formula (2)

The structure represented by
m and n represent an integer of 1 or more,
R _{1 to} R ₈ , Rx and Ry each independently represent a hydrogen atom or a monovalent functional group,
X ₁ , X ₂ and Z each independently represent a divalent functional group,
Y ₁ and Y ₂ each independently represent a divalent or higher functional group containing a carbon atom, an oxygen atom, a hydrogen atom, or a nitrogen atom. )

[2]
The impregnation material for a fiber substrate according to [1] above, wherein the epoxidized polyphenylene ether [A] has an average of 2.5 or more epoxy groups per molecule.
[3]
[1] or [2] in which the epoxidized polyphenylene ether [A] includes a skeleton represented by the following formula (3) at a ratio of 30 to 90% by mass, and the number average molecular weight of the skeleton is 1000 to 4000. ] The impregnation material for fiber base materials of description.

(Wherein, a represents an integer of 1 or more, and R _{9 to} R ₁₂ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms)

[4]
The impregnation material for a fiber substrate according to any one of [1] to [3], further including a plasticizer [D].
[5]
A prepreg obtained by impregnating a fiber base material with the fiber base impregnation material according to any one of [1] to [4].
[6]
The prepreg according to [5] above, wherein the fiber base material is carbon fiber and / or wholly aromatic polyamide fiber.
[7]
A fiber-reinforced composite material obtained by curing the prepreg according to [5] or [6] above.

  According to the present invention, there is provided an impregnating material for a fiber base material suitable for a fiber-reinforced composite material having excellent impregnation properties to a fiber base material, workability such as tackiness as a prepreg, excellent toughness, and excellent heat resistance. Can be provided.

  Hereinafter, the best mode for carrying out the present invention (hereinafter referred to as the present embodiment) will be described in detail. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary.

[Impregnating material for fiber substrate]
The impregnating material for a fiber substrate of the present embodiment is composed of a specific epoxy resin composition described later. The impregnating material for fiber base material is excellent in impregnation property to the fiber base material and can be impregnated uniformly in the fiber base material as it is. From the viewpoint of working efficiency, it is preferably used by being uniformly dissolved or dispersed in a solvent. (An impregnation material for a fiber base material uniformly dissolved or dispersed in the solvent may be referred to as an “epoxy resin varnish”)
The solvent used here is not particularly limited as long as it can dissolve or disperse the fiber base impregnating material. For example, acetone, methyl ethyl ketone, methyl cellosolve, methyl isobutyl ketone, dimethylformamide, propylene glycol monomethyl ether , Toluene, xylene and the like, and mixed solvents thereof are not limited thereto.
It is also possible to adjust the curing rate by further blending a curing accelerator with the above-mentioned impregnating material for the fiber substrate. As the curing accelerator, various known ones can be used without particular limitation, and examples thereof include urea compounds, imidazoles, tertiary amines, phosphines, and aminotriazoles. C] component and a known combination can be used.

[Epoxy resin composition]
The epoxy resin composition of the present embodiment includes an epoxidized polyphenylene ether [A], an epoxy resin [B], and a curing agent [C], and the [A] is represented by the general formula (1). It is an epoxy resin composition.

[Epoxidized polyphenylene ether [A]]
Epoxidized polyphenylene ether [A] is an epoxidized polyphenylene ether having a structure represented by the above formula (1).
The monovalent functional group represented by R _{1 to} R ₄ , Rx in the general formula (1) and / or R _{5 to} R ₈ and Ry in the general formula (2) is, for example, an optionally substituted alkyl group Cycloalkyl group which may be substituted, aryl group which may be substituted, aralkyl group which may be substituted, alkoxy group which may be substituted, and the like.
The “alkyl group” of the optionally substituted alkyl group represented by R _{1 to} R ₈ , Rx and Ry is a linear or branched chain having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms. Represents an alkyl group, and examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, and a hexyl group, and preferably a methyl group , An ethyl group, and more preferably a methyl group.

The “cycloalkyl group” of the optionally substituted cycloalkyl group represented by R _{1 to} R ₈ , Rx and Ry represents a cycloalkyl group having 3 to 8 carbon atoms, such as a cyclopropyl group, cyclobutyl Group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group and the like, and a cyclopentyl group and a cyclohexyl group are preferable.
Examples of the “aryl group” of the optionally substituted aryl group represented by R _{1 to} R ₈ , Rx and Ry include a phenyl group and a naphthyl group, and a phenyl group is preferable.

As the “aralkyl group” of the optionally substituted aralkyl group represented by R _{1 to} R ₈ , Rx and Ry, the alkyl moiety is the “alkyl group” defined above, and the aryl moiety is defined above. In addition, an aralkyl group which is an “aryl group” is exemplified, and examples thereof include a benzyl group, a phenethyl group, a phenylpropyl group, and a 1-naphthylmethyl group, and a benzyl group is preferable.
The “alkoxy group” of the optionally substituted alkoxy group represented by R _{1 to} R ₈ , Rx and Ry is a linear or branched chain having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms. An alkoxy group, for example, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a sec-butoxy group, a tert-butoxy group, a pentyloxy group, a hexyloxy group, and the like, preferably a methoxy group, An ethoxy group.

The alkyl group, cycloalkyl group, aryl group, aralkyl group and alkoxy group represented by R _{1 to} R ₈ , Rx and Ry may be substituted with one or more substituents at substitutable positions. Examples of the substituent include a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom), an alkyl group having 1 to 6 carbon atoms (for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group), aryl group (for example, phenyl group, naphthyl group), aralkyl group (for example, benzyl group, phenethyl group), alkoxy group (for example, methoxy group, ethoxy group) Group),
Etc.
R _{1 to} R ₈ are preferably an alkyl group having 1 to 6 carbon atoms, more preferably a methyl group or an ethyl group, and still more preferably a methyl group, from the viewpoint of solubility in a solvent.

Rx and Ry are preferably hydrogen atoms from the viewpoint of adhesiveness.
Moreover, in General formula (1), m represents the average repeating number of a polyphenylene ether frame | skeleton part, Preferably it is 1-30, More preferably, it shows an integer of 1-15. When m is 30 or less, solubility in a solvent tends to be exhibited.
Furthermore, in General formula (2), n represents the average repeating number of a polyphenylene ether skeleton part, Preferably it is 1-30, More preferably, it shows an integer of 1-15. By setting n to 30 or less, solubility in a solvent tends to develop.

X ₁ in the general formula _(1), the divalent functional group represented by X _2, Z of the general formula (2), for example, an optionally substituted alkylene group, an optionally substituted arylene group Is mentioned.
The “alkylene group” of the optionally substituted alkylene group represented by X ₁ , X ₂ and Z is a group derived by removing one hydrogen atom at any position from the above “alkyl group”. Means a valent group, methylene group, ethylene group, methylethylene group, ethylethylene group, 1,1-dimethylethylene group, 1,2-dimethylethylene group, trimethylene group, 1-methyltrimethylene group, 2-methyl A trimethylene group, a tetramethylene group, etc. are mentioned, Preferably, they are a methylene group, ethylene group, methylethylene group, 1,1-dimethylethylene group, trimethylene group, etc.

The “arylene group” of the optionally substituted arylene group represented by X ₁ , X ₂ , and Z is a group derived by further removing one hydrogen atom at an arbitrary position from the “aryl group”. Means a valent group.
The optionally substituted alkylene group and arylene group represented by X ₁ , X ₂ , and Z may be substituted with one or more substituents at substitutable positions. Examples of the substituent include a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom), an alkyl group having 1 to 6 carbon atoms (for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group), aryl group (for example, phenyl group, naphthyl group), aralkyl group (for example, benzyl group, phenethyl group), alkoxy group (for example, methoxy group, ethoxy group) Group), and the like.

Y ₁ in the general formula _(1), Y ₂ in the general formula (2) represents a functional group containing a carbon atom, an oxygen atom, a hydrogen atom, a nitrogen atom, may contain an epoxy group. The number of functional groups is not particularly limited as long as it is 2 or more. For example, if it is bifunctional, it can take forms such as bisphenol A type, bisphenol F type, and biphenyl type. Moreover, if it is polyfunctionality, forms, such as a phenol novolak type and a cresol novolak type, can be taken. Heat resistance improves in the case of a polyfunctional type.
The ratio of the skeleton part of the polyphenylene ether contained with respect to the epoxidized polyphenylene ether [A] is preferably 30 to 90% by mass, and more preferably 40 to 80% by mass. When the proportion of the polyphenylene ether skeleton is 30% by mass or more, there is a tendency to exhibit an effect of enhancing toughness due to a decrease in crosslinking density, and when it is 90% by mass or less, a polyphenylene ether resin having an epoxy group is produced. Since the viscosity of the resin at the time is moderately low and the production becomes easy, the impregnation property of the resin when the prepreg is prepared becomes good. Moreover, since the resin composition containing epoxidized polyphenylene ether [A] can be cured without phase separation from other epoxy resins, it is suitable for containing a plasticizer [D].

Here, the skeleton portion of polyphenylene ether refers to a portion represented by the general formula (3).
Epoxidized polyphenylene ether [A] may be produced by any method, but is preferably produced by addition reaction of polyphenylene ether and an epoxy compound.
The raw material polyphenylene ether is not particularly limited, and for example, a resin having a repeating unit represented by the general formula (3) can be used.
Specifically, poly (2,6-dimethyl-1,4-phenylene oxide), poly (3,5-dimethyl-1,4-phenylene oxide), poly (2,3,6-trimethyl-1,4) -Phenylene oxide etc. are mentioned.

The number average molecular weight of the polyphenylene ether is preferably 1000 to 4000, more preferably 1500 to 3000. If the number average molecular weight is 4000 or less, the melt viscosity of the resin composition tends to be moderately low and the processability tends to be good, and if it is 1000 or more, excellent toughness is obtained due to a decrease in the crosslinking density of the fiber-reinforced composite material. Indicates.
The method for producing the modified polyphenylene ether is not particularly limited. For example, a method of adding 2,6-xylenol using a phenolic compound having two or more phenolic hydroxyl groups as a seed crystal, or a high molecular weight polyphenylene ether Is subjected to a redistribution reaction, and the number average molecular weight is adjusted to the above preferred range.

A method for subjecting a high molecular weight polyphenylene ether to a redistribution reaction is described in, for example, the literature “Journal of Organic Chemistry, 34, 297 to 303 (1968)” in the presence of a radical initiator. And a method of reducing the molecular weight of the high molecular weight polyphenylene ether resin by reacting with a polyphenol compound such as bisphenol A, tetramethylbisphenol A, tetramethylbiphenyl, dihydroxydiphenyl ether, phenol novolak, cresol novolak, pyrogallol, etc. .
The radical initiator is not particularly limited, and examples thereof include dicumyl peroxide, tert-butyl cumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di-tert-butyl cumi. Luperoxyhexyne-3,2,5-dimethyl-2,5-di-tert-butylperoxyhexane, α, α′-bis (tert-butylperoxy-m-isopropyl) benzene [1,4 (or 1,3) -bis (tert-butylperoxyisopropyl) benzene], diisopropylbenzene hydroperoxide, tert-butyl hydroperoxide, tert-butyl peroxyacetate, tert-butylperoxybenzene, benzoyl peroxide, etc. The peroxide can be used. At this time, cobalt naphthenate, a quaternary ammonium salt, an amine compound, or the like may be further used as a catalyst for the radical initiator.

  The epoxy compound to be reacted with the modified polyphenylene ether is not particularly limited, and for example, glycidyl halide such as epichlorohydrin, an epoxy resin having two or more epoxy groups in the molecule, and the like can be used. Examples of epoxy resins having two or more epoxy groups in the molecule include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, hindered type epoxy resins, biphenyl type epoxy resins, and alicyclic epoxy resins. , Triphenylmethane type epoxy resin, phenol novolac type epoxy resin, cresol novolak type epoxy resin and epoxy resins halogenated from these; diglycidyl ethers such as polyethylene glycol, polypropylene glycol, butanediol, hexanediol, cyclohexanedimethanol, etc. Can be used.

As the epoxy compound, it is particularly preferable to use a polyfunctional epoxy resin having 3 or more epoxy groups in the molecule from the viewpoint of heat resistance. Examples of polyfunctional epoxy resins having 3 or more epoxy groups in the molecule include phenol novolac epoxy resins, cresol novolac epoxy resins, naphthol novolac epoxy resins, bis A novolac epoxy resins, dicyclopentadiene / phenol epoxy Examples thereof include resins, alicyclic amine epoxy resins, aliphatic amine epoxy resins, and the like. These may be used alone or in combination of two or more.
In order to obtain a polyphenylene ether having an epoxy group, it can be obtained, for example, by reacting the modified polyphenylene ether and an epoxy compound at 100 to 200 ° C. for 1 to 20 hours in the presence of a catalyst. The catalyst is not particularly limited, but examples thereof include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkylate salts such as sodium methylate and sodium butyrate, tetrabutylammonium chloride, tetramethylammonium bromide and the like. Quaternary ammonium salts, phosphonium salts such as tetraphenylphosphonium bromide, amyltriphenylphosphonium bromide, imidazoles such as 2-methylimidazole and 2-methyl-4-imidazole, amines such as N, N-diethylethanolamine and potassium chloride One or more of metal halides such as tri-O-tolylphosphine can be used.

  As a specific example, when the epoxy compound is epichlorohydrin, after dissolving the modified polyphenylene ether in the epichlorohydrin at least 1 time, preferably at least 5 times the phenolic hydroxyl group of the polyphenylene ether, an alkali such as sodium hydroxide or potassium hydroxide is dissolved. Although it can manufacture by adding a metal hydroxide, and heating and stirring, this embodiment is not limited to this. The addition amount of the alkali metal hydroxide is 1 equivalent or more with respect to the phenolic hydroxyl group, and the reaction condition is 50 to 100 ° C. for 1 to 10 hours. The resulting product is washed with water or filtered to remove the generated salt, and the unreacted epichlorohydrin is volatilized and recovered, or a poor solvent such as methanol is added to precipitate the resin to obtain an epoxidized polyphenylene ether be able to.

In addition, since the epoxidized polyphenylene ether [A] has an epoxy group in the molecule, the epoxidized polyphenylene ether [A] dissolves not only in an aromatic solvent but also in a mixed solvent including a polar solvent such as a ketone solvent.
The epoxidized polyphenylene ether [A] preferably has an average of 2.5 or more, more preferably an average of 3.0 or more, and even more preferably an average of 4.0 or more epoxy groups per molecule. In the case where the molecule has an average of 2.5 or more epoxy groups in the molecule, it can be cured without further phase separation from other epoxy resins, so that it is more suitable to contain a plasticizer [D]. A method for producing an epoxidized polyphenylene ether having an average of 2.5 or more epoxy groups in the molecule is not particularly limited. For example, at least 5% by mass of the epoxy compound used in the reaction, preferably 10% by mass, more preferably Is a method using a polyfunctional epoxy resin having a functionality of 20% by mass or more. By including many polyfunctional epoxy resins, the average number of epoxy groups of the epoxidized polyphenylene ether obtained can be increased.

Moreover, when making a modified polyphenylene ether and an epoxy compound react, it is preferable to use 2 or more types of epoxy compounds together. In particular, it is preferable to use one or more polyfunctional epoxy resins and bifunctional epoxy resins. Polyfunctional epoxy resin is useful in terms of increasing the number of epoxy groups in the resulting epoxidized polyphenylene ether resin, but it is difficult to dissolve modified polyphenylene ether, and it is easy to cause gelation by reaction with polyphenylene ether. Need to be added. However, when a bifunctional epoxy resin is added during the reaction, the reaction easily occurs because polyphenylene ether is easily dissolved, and further gelation can be prevented. Therefore, the reaction proceeds even in a system in which no solvent is added.
The content of the epoxidized polyphenylene ether [A] is preferably 10 parts by mass to 90 parts by mass, and 20 parts by mass to 100 parts by mass in total of the epoxidized polyphenylene ether [A] and the epoxy resin [B]. More preferably, it is 70 parts by mass.
10 parts by mass or more is preferable from the viewpoint of improving toughness, and 90 parts by mass or less is preferable from the viewpoint of tackiness.

[Epoxy resin [B]]
The component of the epoxy resin [B] is not particularly limited, and various known materials can be appropriately selected and used. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, hindered type epoxy resin, biphenyl type epoxy resin, alicyclic epoxy resin, triphenylmethane type epoxy resin, phenol novolac type epoxy resin, cresol A novolak type epoxy resin and an epoxy resin obtained by halogenating these can be used; diglycidyl ethers such as polyethylene glycol, polypropylene glycol, butanediol, hexanediol, and cyclohexanedimethanol. Further, when selecting from polyfunctional epoxy resins having 3 or more epoxy groups in the molecule, for example, phenol novolac type epoxy resin, cresol novolac type epoxy resin, naphthol novolac type epoxy resin, bis A novolac type epoxy resin, dicyclopentadiene / Phenol epoxy resin, alicyclic amine epoxy resin, aliphatic amine epoxy resin and the like. These may be used alone or in combination of two or more.
From the viewpoint of tackiness, the epoxy resin [B] is preferably 10 parts by mass to 90 parts by mass with respect to 100 parts by mass in total of the epoxidized polyphenylene ether [A] and the epoxy resin [B], and 20 parts by mass. More preferably, it is -70 mass parts.

[Curing agent [C]]
The curing agent [C] is not particularly limited, and various known materials can be appropriately selected and used. From the viewpoint of the reaction rate at the time of curing, a guanidine derivative, an aromatic amine compound, and a novolak type. It is preferably at least one selected from the group consisting of phenol resins and imidazole curing agents.
Specific examples of guanidine derivatives include dicyandiamide derivatives such as dicyandiamide, dicyandiamide-aniline adduct, dicyandiamide-methylaniline adduct, dicyandiamide-diaminodiphenylmethane adduct, dicyandiamide-diaminodiphenyl ether adduct, guanidine nitrate, guanidine carbonate, phosphorus Guanidine salts such as guanidine acid, guanidine sulfamate, aminoguanidine bicarbonate, acetylguanidine, diacetylguanidine, propionylguanidine, dipropionylguanidine, cyanoacetylguanidine, guanidine succinate, diethylcyanoacetylguanidine, dicyandiamidine, N-oxymethyl -N'-cyanoguanidine, N, N'-dicarboethoxyguanidine, etc. Is not particularly limited et.

Specific examples of the aromatic amine compound include, for example, metaphenylene diamine, paraphenylene diamine, 3,3′-diaminodiphenyl sulfone, 4,4′-diaminodiphenyl sulfone, 4,4′-diaminodiphenyl methane, 4, 4 ′. -Diamino diphenyl ether etc. are mentioned, However, It does not specifically limit to these.
Specific examples of the novolak type phenol resin include, but are not limited to, phenol novolak, bisphenol A novolak, cresol novolak, naphthol novolak, and the like. Specific examples of the imidazole curing agent include 2-methylimidazole, 2-methyl-4-ethylimidazole, 2-phenylimidazole, and the like. It is desirable to use 2-methylimidazole from the viewpoint of the number of moles.

  The blending amount of the component [C] is not particularly limited, and is appropriately set according to a desired design. When the component [C] is a guanidine derivative, the amount is preferably 0.6 equivalent to 1.0 equivalent based on the total number of moles of the epoxy group of the epoxy resin [B] and the epoxidized polyphenylene ether of [A]. When the component [C] is an aromatic amine compound, it is preferably 0.8 to 1.2 equivalents relative to the total number of moles of the epoxy group of [A] and the epoxy group of the epoxy resin [B]. In the case where the [C] component is a novolak type phenol resin, the amount is preferably 0.8 equivalents to 1.2 equivalents relative to the number of moles of epoxy groups of the epoxy resin. When the component [C] is an imidazole curing agent, the amount is preferably 0.1 to 10 parts by mass with respect to 100 parts by mass in total of the epoxidized polyphenylene ether of [A] and the epoxy resin [B]. 1 to 5 parts is more preferable. Setting the blending amount within these ranges is preferable from the viewpoint of suppressing the decrease in the crosslinking density and the decrease in Tg of the cured product and ensuring the moisture resistance.

[Plasticizer [D]]
The epoxy resin composition of the present embodiment may further contain a plasticizer [D]. As the plasticizer, a thermoplastic resin or a crosslinked rubber is used.
Examples of the thermoplastic resin include polyether-based thermoplastic resins, polyester-based thermoplastic resins, polyamide-based thermoplastic resins, and the like. Specifically, polyethersulfone, polysulfone, polyimide, polyetherimide, polyetherethersulfone, polyphenylene ether, polysulfone and the like are used.
Examples of the crosslinked rubber include acrylonitrile-butadiene copolymer and styrene-butadiene copolymer, and acrylonitrile-butadiene copolymer is preferable from the viewpoint of compatibility with the epoxy resin.
The content of the plasticizer [D] is not particularly limited as long as the purpose of the present embodiment is not impaired, but 1 to 80 parts by mass with respect to 100 parts by mass in total of the epoxidized polyphenylene ether [A] and the epoxy resin [B]. It is preferable that it is a mass part, and it is more preferable that it is 2 mass parts-70 mass parts.
If it is in the said range, since toughening is possible, without reducing a glass transition temperature, it is preferable.

[Prepreg]
By impregnating the fiber base material with the fiber base impregnating material of the present embodiment, a prepreg having increased mechanical strength and increased dimensional stability is produced.
As the fiber base material, various known materials can be appropriately selected and used, for example, various glass cloths such as roving cloth, cloth, chopped mat, and surfacing mat, asbestos cloth, metal fiber cloth, and other synthetic materials. Or natural inorganic fiber cloth; woven or non-woven fabric obtained from synthetic fibers such as polyvinyl alcohol fiber, polyester fiber, acrylic fiber, wholly aromatic polyamide fiber (aramid fiber), polytetrafluoroethylene fiber; cotton cloth, linen cloth, felt, etc. Natural fiber; carbon fiber; natural cellulosic cloth such as kraft paper, cotton paper, paper-glass mixed paper, etc., among others, carbon fiber cloth having low specific gravity, specific strength, and excellent specific elastic modulus. preferable.

Moreover, these fiber base materials can be used individually by 1 type or in combination of 2 or more types. Further, a prepreg may be produced by adding organic and / or inorganic short fibers to the epoxy resin composition and then semi-curing and molding.
The thickness of the fiber substrate may be appropriately set according to the thickness of the prepreg, desired mechanical strength and dimensional stability, and is usually about 0.05 to 0.30 mm, but is particularly limited. It is not a thing.
The proportion of the fiber base material in the prepreg is appropriately set according to the desired performance of the prepreg, and is not particularly limited, and is preferably 30 to 90% by mass with respect to the total amount of the prepreg, and 40 to 80 More preferably, it is 50 mass%, and it is further more preferable that it is 50-70 mass%. Setting the fiber substrate to 30% by mass or more is preferable from the viewpoint of obtaining a cured product that is more excellent in dimensional stability and strength. On the other hand, setting the fiber substrate to 90% by mass or less is preferable from the viewpoint of obtaining a cured product that is more excellent in adhesion. In addition, in this Embodiment, when it becomes 30-90 mass% with respect to the total amount of a prepreg, it is called favorable impregnation property.

  Examples of the method for producing a prepreg include a method in which a fiber base material is impregnated with an impregnation material for a fiber base material and, if necessary, the impregnation material and then dried. The impregnation of the fiber base material into the fiber base material can be performed by, for example, applying the fiber base material impregnation material to the base material or dipping the fiber base material. This impregnation treatment can be repeated a plurality of times as necessary, and the impregnation is repeated by using a plurality of impregnation materials for fiber bases having different compositions and concentrations at that time, and a desired resin composition is obtained. It is also possible to adjust the amount of resin. Furthermore, when the impregnated fiber base material is dried, it is preferable to adjust the degree of heating so that the fiber base material impregnated material is semi-cured, that is, a so-called B stage state. Here, the B stage refers to a state in which the reaction between the epoxy resin and the curing agent is only partially and the fluidity is maintained. The drying conditions of the impregnated fiber base material are appropriately set according to the desired material, thickness, etc. of the prepreg, and are usually conditions of a drying temperature of 100 to 200 ° C. and a drying time of about 1 to 30 minutes.

During the production of the prepreg, a coupling agent can be added to the fiber base impregnating agent as necessary for the purpose of improving the adhesion at the interface between the fiber base impregnating material and the fiber base. As a coupling agent used here, various well-known things can be selected suitably and can be used, for example, a silane coupling agent, a titanate coupling agent, an aluminum coupling agent, a zirco aluminate coupling agent is mentioned. However, it is not particularly limited to these.
It is desirable to have tackiness at the prepreg stage. Good tackiness means a state in which the resin semi-cured on the fiber base material maintains the adhesiveness without flowing at room temperature. The absence of tackiness means a state where there is no tackiness and it can be easily peeled off when the prepregs are put together.

[Fiber-reinforced composite materials]
The fiber reinforced composite material can be manufactured by laminating the above-described prepreg and heating and pressing. The heating and pressing may be performed according to a conventional method, for example, a temperature of 80 to 300 ° C., a pressure of 0.01 to 100 MPa, and a time of 1 minute to 10 hours, more preferably a temperature of 120 to 250 ° C. and a pressure. It can be carried out under conditions of 0.1 to 10 MPa and a time of 1 minute to 5 hours.

In order to describe the present embodiment in more detail, examples and comparative examples are shown below, but these examples specifically illustrate the description of the present embodiment and the effects obtained thereby. Thus, the present embodiment is not limited at all. In the following, “parts” and “%” mean “parts by mass” and “% by mass”, respectively.
Various characteristics in the following examples and comparative examples were measured according to the following methods.

[Measuring method]
The measuring method of the physical property etc. in this specification is as follows.
(1) Impregnation to fiber base material Toray Co., Ltd. carbon fiber cloth “Torayca cloth CO6343” (trademark) (weight per unit: 198 g / m ² ) or Teijin Techno Products Co., Ltd. mixed with varnish mixed with epoxy resin solution and curing agent The surface state and internal observation of the prepreg impregnated with a company-made aramid fiber “Conex” (trademark) (weight per unit: 254 g / m ² ) for 5 minutes and dried in a 170 ° C. oven for 2 minutes were observed. The bubbles were observed. The case where both were observed was rated as x, the case where only one of them was observed as Δ, and the case where neither was observed as ○.
(2) Tackiness After making a prepreg, the thing with tackiness was made into (circle), and the thing without it was made into x.
(3) Fracture toughness (KI _C )
After the epoxy resin and the curing agent are mixed, it is poured into a casting plate, and the cured epoxy resin composition obtained by heating at 180 ° C. for 2 hours is subjected to an elastoplastic fracture toughness test method (JSME S 001-1981). Measured according to. The test method consists of a test piece of length 20 mm × width 4 mm × thickness 2 mm with a crack of about 2.5 mm in the center of the test piece, 3 at an indenter moving speed of 0.5 mm / min and a fulcrum distance of 17.6 mm. It was measured by a point bending test.

(4) Glass transition temperature
About the hardened | cured material of an epoxy resin composition, the dynamic viscoelasticity measuring apparatus "DDV-25FP" (trademark) by Orientec Co., Ltd. was used, and the test piece of length 20mm * width 4mm * thickness 2mm was 2 degrees C / The temperature was raised in minutes, and the temperature was determined as the temperature at which tan δ was maximum.
(5) Epoxy equivalent It measured according to JISK7236.
(6) Number of epoxy groups Calculated by dividing the molecular weight of the epoxidized polyphenylene ether [A] by the epoxy equivalent.
(7) Ratio of skeleton part in polyphenylene ether The ratio of the skeleton part was obtained by dividing the molecular weight of the polyphenylene ether used by the molecular weight of the epoxidized polyphenylene ether.
(8) Number average molecular weight Columns “shodex A-804” (trademark), “shodex A-803” (trademark), “shodex A-802” (trademark), “shodex A802” (trademark) manufactured by Showa Denko KK Gel permeation chromatography analysis used as a column was performed, and the number average molecular weight was determined by comparison with the elution time of polystyrene having a known molecular weight.

[Modified polyphenylene ether: Production Example 1]
100 g of high molecular weight polyphenylene ether having a number average molecular weight of 17,000 and 8 g of bisphenol A manufactured by Asahi Kasei Chemicals Corporation were dissolved in 150 g of toluene by heating. Further, 0.1 g of cobalt naphthenate was added and the temperature of the solution was heated to 90 ° C. To this, 12.5 g of a 40% xylene solution “Niper BMT-K40” (trademark) of a mixture of benzoyl peroxide and its methyl substitution product manufactured by NOF Corporation (corresponding to 5 g of the mixture of benzoyl peroxide and its methyl substitution product) And 37.5 g of toluene were added over 2 hours. After completion of the dropwise addition, the temperature of the reaction solution was kept at 90 ° C., and stirred for 120 minutes for redistribution reaction. Thereafter, the temperature of the reaction solution was lowered to 70 ° C., and a solution prepared by mixing 75 g of toluene with 25 g of Niper BMT-K40 (corresponding to 10 g of benzoyl peroxide and its methyl substitution product) was added over 2 hours. After completion of the dropwise addition, the temperature of the reaction solution was kept at 70 ° C., and the mixture was further stirred for 180 minutes to perform a redistribution reaction to obtain a modified polyphenylene ether (rPPE). As a result of measuring the reaction solution by gel permeation chromatography, the number average molecular weight of the obtained modified polyphenylene ether was 1,900.

[Production Example 2: Epoxidized polyphenylene ether resin (A-1)]
25 g of cresol novolac type epoxy resin “ECN1299” (trademark) manufactured by Asahi Kasei Epoxy Co., Ltd. and 25 g of bisphenol A type epoxy resin “AER250” (trademark) manufactured by Asahi Kasei Chemicals Corporation were heated to 100 ° C. and mixed with stirring. After mixing well, 0.005 g of NaOCH ₃ was added as a catalyst and stirred for about 15 minutes. Thereafter, the mixture was heated to 165 ° C., and 204 g of modified polyphenylene ether obtained in Production Example 1 (50 g in terms of modified polyphenylene ether) was added over 90 minutes. At this time, the solvent toluene was removed from the reaction system under normal pressure or reduced pressure by flowing nitrogen into the reaction vessel. Then, it stirred at 165 degreeC for 2 hours, and epoxidized polyphenylene ether resin (A-1) was obtained.
10 g of the obtained epoxidized polyphenylene ether resin (A-1) was dissolved in 100 g of toluene, and a large excess of methanol was added to precipitate and precipitate the epoxidized polyphenylene ether. The number average molecular weight of the obtained epoxidized polyphenylene ether was 3060, and the epoxy equivalent was 550. The proportion of the polyphenylene ether skeleton was 62% by mass, and the number of epoxy groups per molecule was 5.6.

[Production Example 3: Epoxidized polyphenylene ether resin (A-2)]
In Production Example 2, except that the cresol novolac type epoxy resin “ECN1299” is changed to the bisphenol A type epoxy resin “AER250” (that is, all the epoxy resins used for modification are changed to the bisphenol A type epoxy resin “AER250”), Modification was performed in the same manner as in Production Example 2 to obtain an epoxidized polyphenylene ether resin (A-2).
10 g of the obtained epoxidized polyphenylene ether resin (A-2) was dissolved in 100 g of toluene, and a large excess of methanol was added to precipitate and precipitate the epoxidized polyphenylene ether. The number average molecular weight of the obtained epoxidized polyphenylene ether was 2630, and the epoxy equivalent was 1390. The proportion of the polyphenylene ether skeleton was 72% by mass, and the number of epoxy groups per molecule was 1.9.

[Epoxy resin [B]]
(B-1): Liquid bisphenol A type epoxy resin ("AER250" (trademark) manufactured by Asahi Kasei Epoxy Corporation) (epoxy equivalent 185 [g / eq])
(B-2) Isocyanate-modified epoxy (Asahi Kasei Epoxy Co., Ltd .: AER4152 “trademark”)

[Curing Agent [C]] (Epoxy Equivalent 335 [g / eq])
(C-1) 4,4′-diaminodiphenylsulfone (Sumitomo Chemical Co., Ltd. “SumiCure S” (trademark)) (amine equivalent 62.1 [g / eq])
(C-2) Dicyandiamide (“Dicy7” (trademark) manufactured by Japan Epoxy Resin Co., Ltd.) (amine equivalent 21 [g / eq])
(C-3) Imidazole-based curing agent (“Curazole 2MZ” (trademark) manufactured by Shikoku Kasei Co., Ltd.)

[Plasticizer [D]]
(D-1) Modified polyphenylene ether (Production Example 1)
(D-2) Polyethersulfone (Sumitomo Chemical Co., Ltd .: Sumika Excel 5003P)
(D-3) Liquid carboxylic acid-modified acrylonitrile-butadiene rubber (manufactured by Ube Industries, Ltd .: CTBN13)

[Examples 1-8, Comparative Examples 1-6]
40 parts by mass of methyl cellosolve is added to a total of 100 parts by mass of the epoxidized polyphenylene ether resin [A] and the epoxy resin [B] as a solvent in the resin compositions having the respective compositions shown in Table 1, and shaken for 1 hour. The fiber base impregnating material was prepared. Next, the obtained impregnating material for the fiber base material is impregnated and applied to a carbon fiber “Torayca Cross CO-6363” (trademark) (weight per unit area: 198 g / m ² ) manufactured by Toray Industries, Ltd. as a fiber base material at 170 ° C. The prepreg was dried and evaluated for impregnation and tackiness, and summarized in Table 1.
Furthermore, the obtained prepreg was cut into 20 cm × 20 cm and thermally cured by a hot plate press at a pressure of 0.4 MPa and a temperature of 180 ° C. for 2 hours to obtain fiber reinforced composite materials, respectively. This fiber-reinforced composite material was cut into a length of 20 mm and a width of 4 mm, and the glass transition temperatures were measured and summarized in Table 1.
Moreover, each resin composition was poured into a casting plate having a length of 20 mm, a width of 4 mm, and a thickness of 2 mm, and heat-cured in an oven at a temperature of 180 ° C. for 2 hours to obtain fiber reinforced composite materials. The fracture toughness (KIc) of this fiber reinforced composite material was measured by the above-described measurement method, and is summarized in Table 1.

[Example 9]
A prepreg and a fiber-reinforced composite material were prepared and impregnated in the same manner as in Example 1 except that an aramid fiber “Conex” (trademark) manufactured by Teijin Techno Products Co., Ltd., which is a wholly aromatic polyamide fiber, was used as the fiber base material. Properties, tackiness, glass transition temperature, and fracture toughness (KIc) were evaluated and summarized in Table 1.

[Example 10]
The same procedure as in Example 1 was conducted except that the resin composition was used as an impregnating material for a fiber base material without adding methyl cellosolve as a solvent, and heated to 80 ° C. and applied under a pressure of 0.1 MPa. A prepreg and a fiber reinforced composite material were prepared, and impregnation property, tack property, glass transition temperature, and fracture toughness (KIc) were evaluated. The physical properties obtained were the same as in Example 1. Thereby, the resin composition of this Embodiment has the favorable impregnation property to a fiber base material, and even if it is a resin composition, it can be said that it impregnates a fiber base material uniformly.

[Comparative Example 7]
Using the resin composition of Comparative Example 4, as in Example 10, an attempt was made to create a prepreg by heating to 80 ° C. and applying a pressure of 0.1 MPa without using a solvent. The base material was impregnated, and the modified polyphenylene ether solidified on the surface of the base material and could not be used as a prepreg. A fiber-reinforced composite material was forcibly created using the obtained prepreg, evaluated, and summarized in Table 1. Compared to those using a solvent, the modified polyphenylene ether was not incorporated into the cured resin, so the fracture toughness (KIc) was much worse.

From the results in Table 1, the following matters can be read.
(1) The epoxy resin composition of this invention can obtain the fiber reinforced composite material which has high fracture toughness and heat resistance, maintaining the impregnation property and tackiness to a fiber base material.
(2) The epoxidized polyphenylene ether used in the epoxy resin composition of the present invention cures uniformly with an epoxy resin having a polyphenylene ether skeleton, and therefore can further improve fracture toughness, which is an effect of a thermoplastic resin ( Comparison between Examples 1 and 4-6 and Comparative Examples 1 and 4-6).

  When the fiber base material impregnation material of the present invention is used, a prepreg having good tackiness and a fiber reinforced composite material having high fracture toughness and toughness can be produced. Such a fiber reinforced composite material can be suitably used for sports applications such as golf shafts and tennis frames, aircraft applications, and the like.

Claims (7)

For fiber base materials comprising an epoxy resin composition comprising an epoxidized polyphenylene ether [A], an epoxy resin [B], and a curing agent [C], wherein the [A] has a structure represented by the following general formula (1) Impregnating material.

(In the formula, A is a hydrogen atom or the following general formula (2)

The structure represented by
m and n represent an integer of 1 or more,
R _{1 to} R ₈ , Rx and Ry each independently represent a hydrogen atom or a monovalent functional group,
X ₁ , X ₂ and Z each independently represent a divalent functional group,
Y ₁ and Y ₂ each independently represent a divalent or higher functional group containing a carbon atom, an oxygen atom, a hydrogen atom, or a nitrogen atom. )   The impregnating material for a fiber substrate according to claim 1, wherein the epoxidized polyphenylene ether [A] has an average of 2.5 or more epoxy groups per molecule. The epoxidized polyphenylene ether [A] includes a skeleton represented by the following formula (3) at a ratio of 30 to 90% by mass, and the number average molecular weight of the skeleton is 1000 to 4000. Impregnating material for fiber substrate.

(Wherein, a represents an integer of 1 or more, and R _{9 to} R ₁₂ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms)   The impregnation material for a fiber base according to any one of claims 1 to 3, wherein the epoxy resin composition further contains a plasticizer [D].   A prepreg obtained by impregnating a fiber base material with the fiber base material impregnation material according to any one of claims 1 to 4.   The prepreg according to claim 5, wherein the fiber substrate is carbon fiber and / or wholly aromatic polyamide fiber.   A fiber-reinforced composite material obtained by curing the prepreg according to claim 5 or 6.