JP2000336191A - Prepreg and fiber-reinforced composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a prepreg useful for producing a tubular body such as a golf club shaft excellent in flexural and/or torsional strength(s) and also excellent in crushing strength and impact strength by impregnating specific carbon fibers with a specific epoxy resin composition. SOLUTION: This prepreg is prepared by impregnating carbon fibers having 5-40 Å of a crystal size Lc in a carbon network plane found through a wide-angle X-ray diffraction method with an epoxy resin composition comprising an epoxy resin such as a bisphenol A-type epoxy resin and a curing agent such as dicyandiamide and having >=8% of a tensile elongation at break of a resin cured product obtained by curing the resin composition at 130 deg.C for 2 h. A bifunctional epoxy resin preferably is included in a content of 70-100 wt.% based on 100 wt.% of all epoxy resins in the above epoxy resin composition. The prepreg is useful for obtaining a fiber reinforced composite material exhibiting high mechanical strength characteristics e.g. in sports uses and aerospace uses.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prepreg for obtaining a fiber-reinforced composite material exhibiting high mechanical strength characteristics in sports, aerospace and general industrial applications.

[0002]

2. Description of the Related Art In producing a fiber-reinforced composite material comprising a reinforcing fiber and a matrix resin, various methods are applied. A prepreg, which is a sheet-like intermediate base material in which a reinforcing fiber is impregnated with a matrix resin, is used. The method used is often used. In this method, multiple prepregs are laminated,
By heating and curing, a molded body that is a fiber-reinforced composite material is obtained.

[0003] Such fiber-reinforced composite materials are lightweight,
Because of their excellent mechanical strength characteristics, they are widely used in sports applications, aerospace applications, and general industrial applications. Especially for sports applications, golf shafts, fishing rods,
Rackets such as tennis and badminton, and sticks such as hockey are mainly used.

[0004] In sports applications, from the viewpoint of enhancing the mechanical strength characteristics, a fiber-reinforced composite material using a prepreg composed of carbon fiber as a reinforcing fiber and epoxy resin as a matrix resin as an intermediate base material is mainly used. Above all, golf shafts, fishing rods and the like are applications in which weight reduction is strongly required, but it is necessary to increase the mechanical strength characteristics of the material before achieving weight reduction.

For this purpose, efforts have been made to enhance the mechanical strength characteristics of the resulting fiber-reinforced composite material with respect to reinforcing fibers, particularly carbon fibers. Accurate analysis of the fracture phenomena revealed that simply increasing the mechanical strength characteristics of the carbon fiber was not sufficient to increase the mechanical strength characteristics of the entire material.

[0006] Golf shafts and fishing rods are usually constructed by winding and laminating several layers of unidirectional prepregs in different directions. When such a structure breaks, the fracture mode changes depending on the material composition and the method of action of the external force (bending, twisting, crushing, etc.), but at 0 ° of any layer (parallel to the reinforcing fiber in the layer). In most cases, the mode of failure, either compression or compression at 90 degrees (orthogonal to the reinforcing fibers in the layer), is the dominant factor, followed by shear failure in many cases.

[0007] Of these, the 0 degree compressive strength depends on the compressive strength of the reinforcing fiber, the elastic modulus of the matrix resin, and the adhesiveness between the reinforcing fiber and the matrix resin. Can be enhanced.

On the other hand, the 90-degree tensile strength depends on the tensile strength of the matrix resin. The tensile strength of the matrix resin tends to increase as the elastic modulus and tensile elongation of the matrix resin increase. However, the elastic modulus and tensile elongation of the matrix resin are in a so-called trade-off relationship in which one of them is sacrificed if the other is increased, and it has been difficult to increase them simultaneously. Even when the tensile strength of the matrix resin is increased, the adhesion between the reinforcing fiber and the matrix resin is insufficient. It was difficult to realize sufficient mechanical strength characteristics.

Accordingly, in order to constantly obtain high mechanical strength characteristics in the obtained fiber-reinforced composite material without depending on the material composition and the method of action of external force, it is necessary to increase the tensile strength and elastic modulus of the matrix resin, It is extremely effective to increase the adhesion between the reinforcing fiber and the matrix resin. Further increasing the adhesiveness also has the effect of increasing the shear strength of the resulting composite material, and provides not only static mechanical strength properties such as compressive strength and tensile strength but also dynamic mechanical strength properties such as impact resistance. Can also be increased.

In order to enhance the adhesiveness between the reinforcing fiber and the matrix resin, it is known that when the reinforcing fiber is a glass fiber, a silane coupling agent treatment is applied to the glass fiber, and when the reinforcing fiber is a carbon fiber, It is known that the fiber is subjected to surface treatment such as electrolytic oxidation treatment.In the case of carbon fiber, although the adhesion between the reinforcing fiber and the matrix resin is improved by the electrolytic oxidation treatment, the strength characteristics of the carbon fiber are simultaneously improved. In some cases.

[0011] By merely performing some treatment on the reinforcing fiber,
There is a limit to improving the adhesion between the reinforcing fiber and the matrix resin, and other methods of improving the adhesion by modifying the matrix resin can be considered.
About the epoxy resin composition to be the matrix resin,
Although there is a finding that it is effective to mix a certain type of thermoplastic resin, the obtained effect is still insufficient at present.

The fiber reinforced composite material has various shapes depending on the application. When the shape is a tubular body, the tensile strength,
Strength properties such as compressive strength, bending strength, and torsional strength are emphasized, and increasing these strength properties is regarded as important.

However, in recent years, in lightweight members such as golf club shafts, which require precise design, the impact strength and crushing strength of the tubular body are becoming increasingly important in addition to the strength characteristics described above. However, with respect to these properties, it is difficult to identify factors that improve the properties by various tests, and thus it is difficult to produce those having sufficient strength properties.

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to provide a prepreg from which a carbon fiber reinforced composite material excellent in various properties can be obtained.

More specifically, the present invention is to provide a prepreg capable of obtaining a tubular body such as a golf club shaft having excellent crushing strength and impact strength while having excellent bending strength and torsional strength. .

[0016]

In order to achieve the above object, the present invention has the following arrangement. That is, an epoxy resin composition containing an epoxy resin and a curing agent and having a tensile elongation of 8% or more of a cured resin obtained by curing at 130 ° C. for 2 hours is a carbon net surface determined by wide-angle X-ray diffraction. Is a prepreg characterized by being impregnated with carbon fibers having a crystal size Lc of 5 to 40 angstroms.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors diligently studied the above-mentioned problems, and at a glance, these problems were solved by a carbon fiber specified and a prepreg containing an epoxy resin composition having specific properties as constituent elements. They have found a solution.

In the present invention, the epoxy resin composition comprises:
It contains an epoxy resin and a curing agent. In the present invention, the epoxy resin means a compound having two or more epoxy groups in a molecule, that is, a bifunctional or more epoxy resin. Specifically, a glycidyl ether obtained from a polyol, a glycidylamine obtained from an amine having a plurality of active hydrogens in a molecule, a glycidyl ester obtained from a polycarboxylic acid, an epoxy resin having a glycidyl group, a plurality of 2 A polyepoxide obtained by oxidizing a compound having a heavy bond is exemplified.

Specific examples of the glycidyl ether obtained from the polyol include bisphenol A as described below.
Examples include bisphenol type epoxy resins such as a type epoxy resin, a bisphenol F type epoxy resin, and a bisphenol S type epoxy resin, and an epoxy resin having a rigid skeleton.

Specific examples of glycidylamine obtained from an amine having a plurality of active hydrogens in the molecule include diglycidylaniline and tetraglycidyldiaminodiphenylmethane which is a glycidylamine obtained from an amine having a plurality of active hydrogens in the molecule. , Triglycidylaminophenol, tetraglycidyl m-xylylenediamine and the like.

Specific examples of the glycidyl ester obtained from the polycarboxylic acid include diglycidyl phthalate, diglycidyl terephthalate, diglycidyl dimer, and the like. Commercial products of diglycidyl phthalate include Shodyne 508
(Registered trademark, manufactured by Showa Denko KK) or the like can be used.

Specific examples of the epoxy resin having a glycidyl group include triglycidyl isocyanurate. As commercial products of triglycidyl isocyanurate, Araldite PT810 (registered trademark, manufactured by Ciba Geigy), Epikote RXE15 (registered trademark, manufactured by Yuka Shell Co., Ltd.), EPITEC (model number, manufactured by Nissan Chemical Co., Ltd.) and the like may be used. Can be.

Specific examples of the polyepoxide obtained by oxidizing a compound having a plurality of double bonds in the molecule include an epoxy resin having an epoxycyclohexane ring. Commercially available epoxy resins having an epoxycyclohexane ring include ERL-4206 (model number, manufactured by Union Carbide Co., epoxy equivalent 70-74), ERL
-4221 (model number, manufactured by Union Carbide, epoxy equivalents 131 to 143), ERL-4234 (model number, manufactured by Union Carbide, epoxy equivalents 133 to 154) and the like can be used. Further, epoxidized soybean oil and the like can also be used as an epoxy resin having an epoxycyclohexane ring.

In the present invention, it is preferable to use a bifunctional epoxy resin having two epoxy groups in a molecule. The bifunctional epoxy resin increases the tensile elongation of the cured resin by lowering the crosslinking density and increasing the distance between crosslinking points. Such a bifunctional epoxy resin is blended in an amount of 70 to 100% by weight, preferably 80 to 100% by weight, based on 100% by weight of the total epoxy resin. If it is less than 70% by weight, the cured resin may have insufficient tensile elongation.

In order to increase the distance between the crosslinking points, 2
It is advantageous to use a bifunctional epoxy resin with a large spacing between two epoxy groups, in which case the epoxy equivalent is 45.
0 or more high molecular weight bisphenol A type epoxy resin and high molecular weight bisphenol F having an epoxy equivalent of 450 or more
At least one high molecular weight bifunctional epoxy resin selected from a type epoxy resin is preferably used. Here, the bisphenol A type epoxy resin is an epoxy resin represented by the following structural formula,

[0026]

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The bisphenol F type epoxy resin is an epoxy resin represented by the following structural formula.

[0028]

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Commercially available high molecular weight bisphenol A type epoxy resins include Epicoat 1001 (epoxy equivalent 450-500), Epicoat 1002 (epoxy equivalent 600-700), Epicoat 1003 (epoxy equivalent 670-770), Epicoat 1004 (epoxy equivalent). Equivalent 875-975), Epicoat 1007 (epoxy equivalent 1750-2200), Epicoat 1009 (epoxy equivalent 2400-3300), Epicoat 1010 (epoxy equivalent 3000-5000) (all registered trademarks, manufactured by Yuka Shell Epoxy Co., Ltd.) , Epicron 1050 (epoxy equivalent 450-500), Epicron 3050 (epoxy equivalent 740-860), Epicron HM-101
(Epoxy equivalent: 3200-3900) (registered trademark, manufactured by Dainippon Ink and Chemicals, Inc.), Epototo YD
-011 (epoxy equivalent 450-500), Epotote YD-014 (epoxy equivalent 900-1000), Epotote YD-017 (epoxy equivalent 1750-210)
0), Epototh YD-019 (epoxy equivalent 2400
To 3000), Epototh YD-022 (epoxy equivalent 4000 to 6000) (registered trademark, manufactured by Toto Kasei Co., Ltd.) and the like.

Commercially available high molecular weight bisphenol F type epoxy resins include Epicoat E4002P (epoxy equivalent 610), Epicoat E4003P (epoxy equivalent 800), and Epicoat E4004P (epoxy equivalent 93).
0), Epicoat E4007P (epoxy equivalent 206
0), Epicoat E4009P (epoxy equivalent 303
0), Epicoat E4010P (epoxy equivalent 440)
0) (Registered trademark, Yuka Shell Epoxy Co., Ltd.)
Manufactured), Epotote YDF-2001 (epoxy equivalent 45
0 to 500), Epototo YDF-2004 (epoxy equivalent: 900 to 1000) (registered trademark, manufactured by Toto Kasei Co., Ltd.) and the like can be used.

At least one high molecular weight bifunctional epoxy resin selected from high molecular weight bisphenol A type epoxy resin and high molecular weight bisphenol F type epoxy resin is
The commercial products exemplified above may be used as pure products or may be used as a mixture of a plurality of types. The high molecular weight bifunctional epoxy resin (when a plurality of types are used, the total thereof) is
The amount is preferably 15 to 70% by weight, more preferably 30 to 60% by weight, based on 100% by weight of the functional epoxy resin. If it is less than 15% by weight, the effect of increasing the tensile elongation of the cured resin may be insufficient. If it exceeds 70% by weight, the rheological properties of the resin composition may be impaired,
The mechanical strength characteristics of the cured resin may be insufficient.

In addition to the above, in the present invention, as the bifunctional epoxy resin, a bisphenol A type epoxy resin, which is a component for improving tensile elongation without impairing the elastic modulus and heat resistance, is reacted with a bifunctional isocyanate. It is preferable to use an oxazolidone type epoxy resin obtained by the above method. As commercial products of the oxazolidone type epoxy resin, XAC4151 (model number, manufactured by Asahi Ciba, epoxy equivalent: 412), XAC4152 (model number, manufactured by Asahi Ciba, epoxy equivalent: 338) and the like can be used. This oxazolidone type epoxy resin has a high molecular weight of 2 as described above.
It can be used by mixing with a functional epoxy resin. The oxazolidone type epoxy resin is preferably blended in an amount of 5 to 50% by weight, and more preferably 15 to 40% by weight, based on 100% by weight of the total bifunctional epoxy resin. 5
If the amount is less than 50% by weight, the effect of increasing the tensile elongation of the cured resin may be insufficient. If the amount exceeds 50% by weight, the rheological properties of the resin composition may be impaired, or the mechanical strength properties of the cured resin may be insufficient. is there.

Also, in the present invention, a low-molecular-weight bisphenol A epoxy resin having an epoxy equivalent of less than 450, a low-molecular-weight bisphenol F-type epoxy resin having an epoxy equivalent of less than 450, and a low-molecular-weight bisphenol S-type epoxy resin having an epoxy equivalent of less than 450 At least one low molecular weight bifunctional epoxy resin selected from resins (epoxy resins obtained by a reaction between bisphenol S and epichlorohydrin) can also be preferably used.

As a commercially available low molecular weight bisphenol A type epoxy resin, Epicoat 825 (epoxy equivalent 1
72-178), Epicoat 828 (epoxy equivalent 18
4-194), Epicoat 834 (epoxy equivalent 230)
270), (the above are registered trademarks, manufactured by Yuka Shell Epoxy Co., Ltd.), Epototo YD-128 (registered trademark, manufactured by Toto Kasei Co., Ltd., epoxy equivalent: 184-194), Epicron 840 (epoxy equivalent: 180-190) ), Epicron 850 (epoxy equivalents 184 to 194), Epicron 830 (epoxy equivalents 165 to 185) (registered trademark, manufactured by Dainippon Ink and Chemicals, Inc.), Sumiepoxy E
LA-128 (registered trademark, manufactured by Sumitomo Chemical Co., Ltd., epoxy equivalent: 184-194), DER331 (model number, manufactured by Dow Chemical Company, epoxy equivalent: 182-192) and the like can be used.

As a commercially available low molecular weight bisphenol F type epoxy resin, Epicoat 806 (epoxy equivalent 1
60-170), Epicoat 807 (epoxy equivalent 16
0 to 175) (registered trademark, manufactured by Yuka Shell Epoxy Co., Ltd.), Epicron 830 (epoxy equivalent: 165 to 175)
180) (registered trademark, manufactured by Dainippon Ink and Chemicals, Incorporated), Epototo YDF-170 (registered trademark,
Epoxy equivalents 160 to 180, manufactured by Toto Kasei Co., Ltd.) can be used.

As a commercially available low-molecular-weight bisphenol S-type epoxy resin, Denacol EX-251 (registered trademark, manufactured by Nagase Kasei Kogyo Co., Ltd., epoxy equivalent: 189) can be used.

The low-molecular weight bifunctional epoxy resin described above is
It can be used by mixing with the high molecular weight bifunctional epoxy resin as described above. The low-molecular-weight bifunctional epoxy resin may be used as a pure product or a mixture of two or more of the commercially available products exemplified above. Such low molecular weight 2
Functional epoxy resin (Total when multiple types are used)
Is 5 to 100% by weight of the total bifunctional epoxy resin.
75% by weight is preferable, and preferably 20 to 50% by weight. If it is less than 5% by weight, the effect of increasing the tensile elongation of the cured resin may be insufficient, and if it exceeds 75% by weight, the rheological properties of the resin composition may be impaired, or the mechanical strength properties of the cured resin may be insufficient. There is.

In the present invention, a trifunctional or higher polyfunctional epoxy resin or a bifunctional epoxy resin having a rigid skeleton can be used to further increase the elastic modulus of the cured resin. A bifunctional epoxy resin having a rigid skeleton is particularly preferably used because it has the effect of improving the elastic modulus while minimizing the decrease in tensile elongation of the cured resin.

Specific examples of the polyfunctional epoxy resin having three or more functional groups include a novolak type epoxy resin which is a glycidyl ester of novolak obtained from a phenol derivative such as phenol, alkylphenol, or halogenated phenol; Glycidylamine obtained from an amine having tetraglycidyldiaminodiphenylmethane, triglycidylaminophenol,
Polyfunctional glycidylamine type epoxy resin such as tetraglycidyl m-xylylenediamine, triglycidylaminocresol, tetrakis (glycidyloxyphenyl)
Examples include polyfunctional glycidyl ether type epoxy resins such as ethane and tris (glycidyloxy) methane.

Commercial products of novolak type epoxy resins include Epicoat 152 (registered trademark, manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent: 172 to 179), Epicoat 154 (registered trademark, manufactured by Yuka Shell Epoxy Co., Ltd.), Epoxy equivalent 176-181), DER438 (registered trademark,
Dow Chemical Co., epoxy equivalent 176-181), Araldite EPN1138 (registered trademark, Ciba Co., epoxy equivalent 176-181), Araldite EPN113
9 (registered trademark, manufactured by Ciba, epoxy equivalent: 172 to 17)
9), Epotote YCPN-702 (registered trademark, epoxy equivalent: 200 to 230, manufactured by Toto Kasei Co., Ltd.), BREN
-105 (epoxy equivalents 262 to 278, manufactured by Nippon Kayaku Co., Ltd.) or the like can be used.

Specific examples of glycidylamine include “Sumi-Epoxy” ELM434 (manufactured by Sumitomo Chemical Co., Ltd., epoxy equivalent: 110 to 130), which is diglycidylaniline and tetraglycidyldiaminodiphenylmethane, and tetraglycidyl m-xylylenediamine. TETRAD-X
(Mitsubishi Gas Chemical Co., Ltd., epoxy equivalent 90-105)
And the like.

Commercial products of triglycidylaminophenol include Sumi-Epoxy ELM120 (registered trademark, manufactured by Sumitomo Chemical Co., Ltd., epoxy equivalent 118) which is triglycidyl-m-aminophenol, and triglycidyl-p-aminophenol. Araldite MY0 which is phenol
510 (registered trademark, manufactured by Ciba Geigy, epoxy equivalent 9
4 to 107) can be used.

As commercial products of tetraglycidyl m-xylylenediamine, TETRAD-X (model number, manufactured by Mitsubishi Gas Chemical Co., Ltd., epoxy equivalent 94-107) and the like can be used.

These polyfunctional epoxy resins can be used by mixing with the high-molecular weight bifunctional epoxy resin or the low molecular weight bifunctional epoxy resin as described above. The commercially available polyfunctional epoxy resin may be used as a pure product or as a mixture of a plurality of types. Multifunctional epoxy resin (when using multiple types, total of them)
Has a side effect of increasing the cross-linking density and sacrificing tensile elongation, so it is preferable to add 0 to 30% by weight, preferably 0 to 20% by weight based on 100% by weight of the total epoxy resin.

Further, specific examples of the bifunctional epoxy resin having a rigid skeleton include epoxy resins represented by the following general formulas (I) to (V).

[0046]

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(Where R ^{1 to} R ⁴ each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 8 carbon atoms)

[0048]

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(Here, R ^{5 to} R ⁸ each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 8 carbon atoms.)

[0050]

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[0051]

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[0052]

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The epoxy resin represented by the general formula (I)
It can be obtained by the reaction of resorcin, hydroquinone, pyrocatechol, or a derivative thereof with epichlorohydrin.

Commercial products of the epoxy resin represented by the general formula (I) include resorcin diglycidyl ether Denacol EX-201 (registered trademark, manufactured by Nagase Kasei Kogyo Co., Ltd., epoxy equivalent: 118), hydroquinone diglycidyl Denacol EX-203 which is an ether (registered trademark, manufactured by Nagase Kasei Kogyo Co., Ltd., epoxy equivalent 112),
Epotote YDC-1312 which is 2,5-di-t-butylhydroquinone diglycidyl ether (registered trademark, manufactured by Toto Kasei Co., Ltd., epoxy equivalent 170-185), 2,
RE-701 (model number, Nippon Kayaku Co., Ltd., epoxy equivalent: 143), which is 3,5-trimethylhydroquinone diglycidyl ether, and the like can be used.

The epoxy resin represented by the general formula (II)
It is obtained by the reaction of 4,4′-dihydroxybiphenyl or a substituent derivative thereof with epichlorohydrin.

Commercially available epoxy resins represented by the general formula (II) include 4,4'-dihydroxy-3,3 ',
Epicoat YX4000 which is 5,5′-tetramethylbiphenyl diglycidyl ether (registered trademark, manufactured by Yuka Shell Epoxy Co., epoxy equivalent 180-192),
Epicoat YL6121H (registered trademark, manufactured by Yuka Shell Epoxy Co., Ltd.), which is a mixture of 4,4'-dihydroxy-3,3 ', 5,5'-biphenyldiglycidyl ether and 4,4'-dihydroxybiphenyldiglycidyl ether , Epoxy equivalent 175) and the like can be used.

The epoxy resin represented by the general formula (III) is obtained by reacting tetrabromobisphenol A with epichlorohydrin.

As a commercially available epoxy resin represented by the general formula (III), Epicoat 5050 (registered trademark, manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent: 380-41)
0), Epicron 152 (registered trademark, manufactured by Dainippon Ink and Chemicals, Inc., epoxy equivalent: 340 to 380),
Epoxy ESB-400T (registered trademark, manufactured by Sumitomo Chemical Co., Ltd., epoxy equivalent: 380 to 420), Epototo YBD-360 (registered trademark, manufactured by Toto Kasei Co., Ltd., epoxy equivalent: 350 to 370) and the like can be used. it can.

The epoxy resin represented by the general formula (IV)
Obtained by the reaction of dihydroxynaphthalene with epichlorohydrin.

Commercially available epoxy resins represented by the general formula (IV) include 1,6-dihydroxynaphthalenediglycidyl ether, Epicron HP-4032H (registered trademark, manufactured by Dainippon Ink and Chemicals, Inc.) Equivalents 250) and the like can be used.

The epoxy resin represented by the general formula (V)
It is obtained by the reaction of 9,9-bis (4-hydroxyphenyl) fluorene with epichlorohydrin.

Commercially available epoxy resins represented by the general formula (V) include Epon HPT resin 1079 (registered trademark, manufactured by Shell Co., epoxy equivalent 250-260), ES
F-300 (model number, manufactured by Nippon Steel Chemical Co., Ltd., epoxy equivalent 24
6) etc. can be used.

As the epoxy resin having a rigid skeleton, at least one selected from the epoxy resins represented by the general formulas (I) to (V) can be used. The epoxy resin having a rigid skeleton has a high molecular weight of 2 as described above.
It can be used in combination with a functional epoxy resin, a low molecular weight bifunctional epoxy resin, or a polyfunctional epoxy resin.
The epoxy resin having a rigid skeleton may be a pure product or a mixture of two or more of the commercially available products exemplified above. The polyfunctional epoxy resin (when a plurality of types are used, the total thereof) has a side effect of increasing the crosslink density and sacrificing the tensile elongation. Therefore, 0 to 70% by weight, preferably 0% based on 100% by weight of the total epoxy resin. It is good to mix it by 50% by weight.

In the present invention, the epoxy resin composition comprises:
It is preferable to include one of the following components (A) and (B). (A) a compound having one functional group capable of reacting with an epoxy resin or a curing agent in the molecule and one or more amide bonds (B) a polyester polyurethane having an aromatic ring in the molecule In the present invention, the component (A) Is compounded as a highly polar compound for enhancing the adhesion between the reinforcing fibers and the matrix resin (hereinafter simply referred to as adhesion).

Here, the amide bond means a partial structure composed of a group selected from a carbonyl group, a thiocarbonyl group, a sulfonyl group, and a phosphoryl group, and a nitrogen atom bonded to carbon in the functional group by a single bond. A typical compound having an amide bond is carboxylic acid amide, but may be a compound having an amide bond in a part of the ring,
Alternatively, a compound having a more complicated partial structure such as imide, urethane, urea, biuret, hydantoin, carboxylic hydrazide, hydroxamic acid, semicarbazide, semicarbazone, or the like may be used.

The carbonyl oxygen of the amide bond forms a strong hydrogen bond with a hydrogen atom bonded to oxygen or nitrogen. Therefore, the adhesiveness is enhanced by hydrogen bonding with a hydrogen atom such as a carboxyl group or a hydroxyl group present on the surface of the carbon fiber.

The carbonyl group in the amide bond is a strong permanent dipole, forms an induced dipole inside a reinforcing fiber having a high polarizability such as carbon fiber, and enhances the adhesion due to the electric attraction between the dipole and the dipole. Can be

If the compound having an amide bond does not have a functional group capable of reacting with the epoxy resin or the curing agent, the adhesion cannot be sufficiently increased due to phase separation, or the heat resistance is greatly reduced due to the action as a plasticizer. However, when the compound having an amide bond has a functional group that can react with an epoxy resin or a curing agent, with the curing of the epoxy resin composition, a part of a network of a cured product of the epoxy resin composition may be formed. Therefore, there is no possibility that such an adverse effect occurs.

An epoxy resin composition containing a compound having two or more functional groups capable of reacting with an epoxy resin or a curing agent and one or more amide bonds in the molecule is used as a fiber-reinforced composite material (hereinafter abbreviated as composite material). )) Is known, but according to these known techniques, the adhesiveness is not sufficiently enhanced, but the functional group capable of reacting with an epoxy resin or a curing agent in a molecule found by the present inventors. An epoxy resin composition containing a compound having one and one or more amide bonds has remarkably improved adhesiveness.

The reason for this is that a compound having two or more functional groups capable of reacting with an epoxy resin or a curing agent is chemically bonded to the epoxy resin network at two or more places, so that the oxygen of the carbonyl group in the partial structure containing an amide bond is changed. Compounds having one functional group that can react with the epoxy resin or curing agent, while atoms cannot approach the surface of the reinforcing fiber sufficiently, are included in that compound because they are chemically bonded to the epoxy resin network at only one place. The present inventors presume that the degree of freedom of movement of the partial structure containing an amide bond is large, and that the oxygen atom of the carbonyl group easily approaches the surface of the reinforcing fiber.

It should be noted that, by blending the component (A), not only the adhesiveness can be improved, but also the flexural modulus of the cured product of the epoxy resin composition can be increased. This is presumed to be because the oxygen of the hydroxyl group and the carbonyl group present in the epoxy resin forms a strong hydrogen bond and restricts the molecular motion.

The functional groups capable of reacting with the epoxy resin include carboxyl groups, phenolic hydroxyl groups, amino groups,
Examples include a secondary amine structure and a mercapto group. Examples of the functional group that can react with the curing agent include an epoxy group and a double bond conjugated to a carbonyl group. The double bond conjugated with the carbonyl group performs a Michael addition reaction with an amino group or a mercapto group in the curing agent.

Specific examples of the compound having one carboxyl group and having an amide bond include succinamic acid, oxamic acid, N-acetylglycine, N-acetylalanine, 4-acetamidobenzoic acid, N-acetylanthranilic acid, 4-acetamidobutyric acid, 6-acetamidohexanoic acid, hippuric acid, 5-hydantoin acetic acid, pyroglutamic acid, 2- (phenylcarbamoyloxy) propionic acid and the like.

Specific examples of the compound having one phenolic hydroxyl group and having an amide bond include salicylamide and
4-hydroxybenzamide, 4-hydroxyphenylacetamide, 4-hydroxyacetanilide, 3-hydroxyacetanilide and the like.

Specific examples of the compound having one amino group and having an amide bond include 4-aminobenzamide, 3
-Aminobenzamide, 4'-aminoacetanilide,
4-aminobutylamide, 6-aminohexaneamide,
3-aminophthalimide, 4-aminophthalimide and the like can be mentioned.

Specific examples of compounds having one secondary amine structure and having an amide bond include nipecotamide, N, N
-Diethylnipecotamide, isonipecotamide, 1-acetylpiperazine and the like.

Specific examples of the compound having one mercapto group and having an amide bond include 4-acetamidothiophenol, N- (2-mercaptoethyl) acetamide and the like.

Specific examples of the compound having one epoxy group and having an amide bond include glycidamide, N-phenylglycidamide, N, N-diethylglycidamide, N-
Methoxymethylglycidamide, N-hydroxymethylglycidamide, 2,3-epoxy-3-methylbutyramide, 2,3-epoxy-2-methylpropionamide,
9,10-epoxystearamide, N-glycidylphthalimide and the like.

The compound having one double bond conjugated to a carbonyl group and having an amide bond may have the same or different carbonyl group conjugated to the double bond as the carbonyl group of the amide bond. good. Examples of the compound in which the carbonyl group conjugated to the double bond is the same as the carbonyl group of the amide bond include amides of α, β-unsaturated carboxylic acids and substituent derivatives having a substituent on the nitrogen atom thereof. Specifically, acrylamide, methacrylamide,
N, N-dimethylacrylamide, N, N-diethylacrylamide, N-tert-butylacrylamide,
Nn-butoxymethylacrylamide, N-isopropylacrylamide, N-butylacrylamide, N-
Examples include hydroxymethylacrylamide, N-methoxymethylacrylamide, diacetoneacrylamide, 1-acryloylmorpholine, 1-acryloylpiperidine and the like. In addition, imides of unsaturated dicarboxylic acids such as maleimide, N-ethylmaleimide, N-phenylmaleimide, and the like also apply. On the other hand, examples of the compound in which the carbonyl group conjugated to the double bond is not the same as the carbonyl group of the amide bond include 2- (phenylcarbamoyloxy) ethyl methacrylate.

Commercially available compounds having one amide bond and one double bond conjugated to a carbonyl group include DM
AA (model number, manufactured by Kojin Co., Ltd.), acryloylmorpholine (manufactured by Kojin Co., Ltd.), acrylamide (manufactured by Nakarai Tesque Co., Ltd.), N-hydroxymethylacrylamide (manufactured by Nitto Chemical Industry Co., Ltd.), Denacol EX731 (Registered trademark, manufactured by Nagase Kasei Kogyo Co., Ltd.), p-hydroxyphenylacetamide (manufactured by Otsuka Chemical Co., Ltd.) and the like can be used.

In the present invention, one or more components (A) can be blended in the epoxy resin composition.

Component (A) (when a plurality of types are used, the sum of them) is 0.1 to 100 parts by weight of all epoxy resins.
It is preferable to add 5 to 15 parts by weight. If the amount is less than 0.5 part by weight, the adhesiveness of the obtained composite material cannot be sufficiently enhanced, and if the amount exceeds 15 parts by weight, there may be a problem such as a decrease in heat resistance of the obtained composite material.

The component (A) may be a liquid or a solid at room temperature. When a solid is used, it may be blended in the epoxy resin composition and then dissolved by means such as heating and stirring, or may be blended without being dissolved. When compounding without dissolving the solid, it is preferable to use it after pulverizing to a particle size of 10 μm or less.

In the present invention, the component (B) is compounded as a compound for increasing the elastic modulus without lowering the tensile elongation of the cured resin.

That is, since the urethane structure present in the molecule of the constituent element (B) forms a strong hydrogen bond with the hydroxyl group present in the epoxy resin and restrains the molecular motion, the elastic modulus of the cured resin is increased. It is estimated that

The constituent element (B) has a structure in which the ester structure in the molecule reacts with an amino group, mercapto group, phenolic hydroxyl group or the like in the curing agent by a nucleophilic substitution reaction to form a part of the network of the cured epoxy resin. Therefore, there is also a characteristic that phase separation does not occur and the elastic modulus of the cured resin is hardly reduced.

In the present invention, the constituent component (B) includes, for example, a polyisocyanate having two or more isocyanate groups in a polyester polyol obtained by polycondensation of a polyvalent carboxylic acid and a polyhydric alcohol, and optionally a chain extension. Polyester polyurethane obtained by applying a conventionally known method such as a one-shot method or a prepolymer method using an agent can be used. In the present invention, one or more components (B) can be blended in the resin composition.

Examples of the polycarboxylic acid include malonic acid, succinic acid, succinic anhydride, glutaric acid, adipic acid, azelaic acid, sebacic acid, phthalic acid, phthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, and isophthalic acid. Acid, terephthalic acid, nadic acid anhydride, maleic acid, maleic anhydride, fumaric acid, itaconic acid, citraconic acid, trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, etc., among which succinic acid And aliphatic polycarboxylic acids such as adipic acid.

As the polyhydric alcohol, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butylene glycol, 1,4
-Butylene glycol, 1,5-butylene glycol,
1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol,
Dipropylene glycol, 2,2,4-trimethyl-
1,3-pentanediol, cyclohexanediol,
Bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, glycerin, trimethylolpropane, trimethylolethane, pentaerythritol and the like, among which 1,2-propylene glycol, 1,
4-butylene glycol, 1,6-hexanediol and the like are preferably used.

As the polyisocyanate, an aromatic polyisocyanate is preferably used because the cured product obtained by heating and curing the epoxy resin composition has a higher elastic modulus. For example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-
Diphenylmethane diisocyanate, tolidine diisocyanate, 1,5-naphthalene diisocyanate, isophorone diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, xylylene diisocyanate, tetramethyl xylene diisocyanate, triphenylmethane triisocyanate, tris (isocyanate phenyl) thiophosphate, and These oligomers are exemplified, and among them, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, and 4,4′-diphenylmethane diisocyanate are preferably used.

As the chain extender, 1,2-propylene glycol, 1,4-butanediol, 1,6-hexanediol, polyethylene glycol, polypropylene glycol and a mixture thereof are used.

In the present invention, the component (B) is used in an amount of 1 to 15 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the total epoxy resin. If the amount is less than 1 part by weight, the effect of improving the elastic modulus of the cured resin becomes insufficient, and if it exceeds 15 parts by weight, the heat resistance of the cured resin may decrease.

In the present invention, the epoxy resin composition contains 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylsulfone, and 3,3 ′ as curing agents.
Aromatic amines having active hydrogen such as diaminodiphenyl sulfone, m-phenylenediamine, m-xylylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine, bis (aminomethyl)
Aliphatic amines having active hydrogen such as norbornane, bis (4-aminocyclohexyl) methane, dimer acid ester of polyethyleneimine, and compounds having active hydrogen such as epoxy compounds, acrylonitrile, phenol and formaldehyde, thiourea Tertiary amines having no active hydrogen such as modified amine, dimethylaniline, dimethylbenzylamine, 2,4,6-tris (dimethylaminomethyl) phenol and 1-substituted imidazole, dicyandiamide, tetramethyl Guanidine, hexahydrophthalic anhydride,
Tetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, carboxylic anhydrides such as methylnadic anhydride, polycarboxylic acid hydrazides such as adipic hydrazide and naphthalenedicarboxylic acid hydrazide, polyphenol compounds such as novolak resins, Polymercaptans such as esters of thioglycolic acid and polyol, Lewis acid complexes such as boron trifluoride ethylamine complex, aromatic sulfonium salts and the like can be used.

These curing agents may be used in combination with a suitable curing aid to enhance the curing activity.
Preferred examples include dicyandiamide, 3-phenyl-1,1-dimethylurea, 3- (3,4-dichlorophenyl) -1,1-dimethylurea (DCMU),
Examples of combining urea derivatives such as (3-chloro-4-methylphenyl) -1,1-dimethylurea and 2,4-bis (3,3-dimethylureido) toluene as curing aids, carboxylic anhydrides And a combination of a novolak resin with a tertiary amine as a curing aid.

In the present invention, a high molecular compound, organic particles, inorganic particles, and other components can be added to the epoxy resin composition as a modifier.

As the polymer compound to be mixed in the epoxy resin composition of the present invention, a thermoplastic resin is preferable.
By blending the thermoplastic resin, effects such as viscosity control at the time of impregnating the resin, handleability of the prepreg, and improvement of the adhesiveness can be enhanced.

The thermoplastic resin used here is particularly preferably a thermoplastic resin having a hydrogen-bonding functional group which can be expected to have a synergistic effect in order to improve adhesiveness. Specific examples of the hydrogen-bonding functional group include an alcoholic hydroxyl group, an amide bond, and a sulfonyl group.

Examples of the thermoplastic resin having an alcoholic hydroxyl group include polyvinyl acetal resins such as polyvinyl formal and polyvinyl butyral, and polyvinyl alcohol and phenoxy resins. Examples of the thermoplastic resin having an amide bond include sulfonyl groups such as polyamide and polyimide. Examples of the thermoplastic resin include polysulfone and the like. Polyamide, polyimide and polysulfone may have a functional group such as an ether bond or a carbonyl group in the main chain. The polyamide may have a substituent at the nitrogen atom of the amide group.

Commercially available thermoplastic resins having a hydrogen-bonding functional group which are soluble in an epoxy resin include polyvinyl acetal resins such as denkabutyral and denkaformal (registered trademark, manufactured by Denki Kagaku Kogyo KK) and vinylek (Registered trademark, manufactured by Chisso Corporation), UCARPKHP (model number, manufactured by Union Carbide), which is a phenoxy resin,
As a polyamide resin, Macromelt (registered trademark, manufactured by Henkel Hakusui Co., Ltd.), Amilan CM4000 (registered trademark, manufactured by Toray Industries, Inc.), Ultem (registered trademark, manufactured by General Electric Co., Ltd.), a polyimide, Matri
Victrex (registered trademark, Mitsui Toatsu Chemicals, Inc.) as mid5218 (registered trademark, manufactured by Ciba) and polysulfone
And UDEL (registered trademark, manufactured by Union Carbide Co.) can be used.

The thermoplastic resin is used in an amount of 1 to 20 parts by weight based on 100 parts by weight of the epoxy resin in order to give the epoxy resin composition an appropriate viscoelasticity and obtain good physical properties in the obtained composite material.
It is preferable to mix them in parts by weight, and preferably 2 to 10 parts by weight.

As the organic particles to be added to the epoxy resin composition of the present invention, rubber particles and thermoplastic resin particles are preferably used. These particles have the effect of improving the toughness of the matrix resin and the impact resistance of the composite material.

As the rubber particles, crosslinked rubber particles and core-shell rubber particles obtained by graft-polymerizing a heterogeneous polymer on the surface of the crosslinked rubber particles are preferably used.

Commercially available crosslinked rubber particles include XER-91 (model number, manufactured by Nippon Synthetic Rubber Industry Co., Ltd.) composed of a crosslinked product of a carboxyl-modified butadiene-acrylonitrile copolymer, and CX-MN composed of acrylic rubber fine particles. Series (model number, manufactured by Nippon Shokubai Co., Ltd.), YR-500 series (model number, manufactured by Toto Kasei Co., Ltd.) and the like can be used.

Examples of commercially available core-shell rubber particles include paraloid EXL-2655 (registered trademark, manufactured by Kureha Chemical Industry Co., Ltd.) made of butadiene / alkyl methacrylate / styrene copolymer, acrylic acid ester / methacrylic acid ester copolymer. Staphyloid AC-335 consisting of coalescence
5, TR-2122 (registered trademark, model number, manufactured by Takeda Pharmaceutical Co., Ltd.), PARALOIDEXL-2611, E comprising butyl acrylate / methyl methacrylate copolymer
XL-3387 (model number, manufactured by Rohm & Haas) or the like can be used.

As the thermoplastic resin particles, polyamide or polyimide particles are preferably used. A commercially available polyamide particle, manufactured by Toray Industries, Inc., model number: SP-
500, Orgasol (registered trademark) manufactured by ATOCHEM
Etc. can be used.

As the inorganic particles, silica, alumina, smectite, synthetic mica and the like are preferably used. These inorganic particles are mainly blended for rheological control, that is, for increasing the viscosity of the resin and imparting thixotropic properties.

The epoxy resin composition of the present invention has a composition as described above, and the cured resin exhibits high tensile elongation and elastic modulus.

In the present invention, it is preferable that the epoxy resin composition has excellent elongation, elastic modulus, and so-called plastic deformability in obtaining a tubular body such as a golf club shaft. Specifically, the cured resin obtained by curing at 130 ° C. for 2 hours has a tensile elongation of 8% or more, preferably 10% or more. The flexural modulus of the cured resin obtained by curing at 130 ° C. for 2 hours is 3.1.
GPa or more, preferably 3.3 GPa or more, more preferably 3.5 GPa or more. It is to be noted that a tensile elongation of 16% is sufficient for achieving the effects of the present invention, whereas a flexural modulus of 7.5 GPa is often sufficient for achieving the effects of the present invention.

In the present invention, the plastic deformability can be evaluated by using the three-point bending amount of the cured product (formed plate) and the elastic modulus G ′ in the rubber state obtained from the dynamic viscoelasticity measurement as an index. it can. That is, the molded plate obtained by curing the epoxy resin composition at 130 ° C. for 2 hours has a three-point bending deflection of 1
The elastic modulus G ′ (MPa) of the rubber state in dynamic viscoelasticity at 0 to 25 mm, preferably 15 to 25 mm or at a frequency of 0.5 Hz is represented by the following equation (1), preferably the following equation (2). It is good to satisfy.

1 ≦ G ′ ≦ 8 (1) 1 ≦ G ′ ≦ 5 (2) In the obtained composite material, in order to increase the 0-degree compressive strength and the 90-degree tensile strength, the tensile elongation of the matrix resin is required. It is preferable that not only the elastic modulus is high but also the adhesiveness is as high as possible.

Therefore, in the present invention, in order to have a synergistic action with the epoxy resin composition having high tensile elongation and adhesiveness, the reinforcing fibers have high adhesiveness and are more durable. It is preferable to use carbon fiber from which the body can be obtained. In the present invention, as other reinforcing fibers, glass fibers, aramid fibers, boron fibers, alumina fibers, silicon carbide fibers, etc., which have been surface-treated to appropriately increase the adhesiveness, can also be used. May be used in combination of two or more.

In the present invention, various types of carbon fibers such as acrylic, pitch and rayon can be used as the carbon fibers. Above all, acrylic carbon fibers from which high-strength carbon fibers can be easily obtained are preferably used.

The carbon fiber in the present invention has a specific ratio of the atomic ratio of oxygen O to carbon C measured by X-ray photoelectron spectroscopy, that is, the surface specific oxygen concentration (hereinafter abbreviated as O / C) within a specific range. Then, affinity and adhesiveness with the epoxy resin composition can be improved. Specifically, the carbon fiber in the present invention has an O / C of 0.30 or less, preferably 0.25 or less, and more preferably 0.20 or less. When O / C exceeds 0.30, the chemical bond between the functional group present in the epoxy resin composition and the functional group present on the surface layer of the carbon fiber itself becomes stronger, but the chemical bond itself becomes stronger than the carbon fiber substrate itself. Since an oxide layer having considerably poor strength characteristics occupies the surface portion of the carbon fiber, the resulting composite material may have reduced adhesiveness and the mechanical strength characteristics of the composite material may be impaired. here,
The lower limit of O / C is 0.02, preferably 0.04, and more preferably 0.06. If the O / C is less than 0.02, the reactivity or progress of the chemical bond between the carbon fiber and the epoxy resin composition may decrease.

Further, the carbon fiber in the present invention has an atomic ratio of nitrogen N to carbon C measured by X-ray photoelectron spectroscopy, that is, a surface specific nitrogen concentration (hereinafter abbreviated as N / C).
Is within a specific range, it is possible to improve the affinity and adhesiveness with the epoxy resin composition. Specifically, the carbon fiber in the present invention has an N / C of 0.02 or more, preferably 0.03 or more, and more preferably 0.04 or more. If the N / C is less than 0.02, the reactivity or progress of the chemical bond between the carbon fiber and the epoxy resin composition may decrease. Here, the upper limit of N / C is 0.30, preferably 0.25, and more preferably 0.2.
20 is good. When N / C exceeds 0.30, the chemical bond between the functional group present in the epoxy resin composition and the functional group present on the surface of the carbon fiber itself becomes strong, but the carbon fiber and the epoxy resin composition And the degree of progress of the reaction may become excessive, and the effect of improving the adhesiveness may be insufficient.

The carbon fiber according to the present invention has a surface carboxyl group concentration COOH / C (hereinafter abbreviated as COOH / C) of 0.2% as measured by chemically modified X-ray photoelectron spectroscopy.
It is preferably at least 0.5%. Here, the upper limit of COOH / C is 3.0%, preferably 2.0%. If COOH / C is less than 0.2%, the affinity with a matrix resin described below decreases, and CFRP
In some cases, the effect of improving the in-plane shear strength may be insufficient. When COOH / C exceeds 3.0%, the affinity between the carbon fiber and the matrix resin becomes strong, but the oxide layer having a strength characteristic significantly lower than the strength characteristic of the carbon fiber itself causes the surface of the carbon fiber to change. Therefore, the strength characteristics of the obtained CFRP tend to be impaired, and the curing speed of the matrix resin may be delayed.

Further, in the present invention, it is preferable to use a carbon fiber having a small crystal and a large number of curable points, since the adhesiveness is further enhanced.

In the present invention, the 0-degree tensile modulus E (GPa) of the carbon fiber and the crystal size Lc (Ongstrom) of the carbon network plane determined by wide-angle X-ray diffraction preferably satisfy the following expression (3). It is more preferable to satisfy the following expression (4).

Lc ≦ 0.14 × E-13.0 (3) Lc ≦ 0.14 × E-14.0 (4) When the carbon fiber has a high elastic modulus, a carbon network determined by wide-angle X-ray diffraction is obtained. Since the crystal size Lc of the plane increases, the adhesiveness tends to decrease. In the present invention, it is important to reduce the crystal size Lc of the carbon network surface to prevent a decrease in adhesiveness while maintaining a high tensile modulus of fiber. From the viewpoint of improving the mechanical strength characteristics of the obtained composite material, the carbon fiber in the present invention, in which the trade-off relation with the tensile modulus is improved, has a tensile elongation of 1.1% or more, preferably 1%. It is preferably at least 4%.

Incidentally, if the tensile strength is 2.5%, it is often sufficient to achieve the effects of the present invention.

Further, it is preferable to use a carbon fiber having the highest possible adhesiveness as long as the elastic modulus is the same level. That is, the adhesiveness can be enhanced by reducing the diameter of the carbon fiber and increasing the surface area of the carbon fiber. Specifically, the diameter of the single yarn is 4 to 7 μm, preferably 4 to 6 μm.
m, and the cross-sectional shape of the carbon fiber is substantially a perfect circle, or the diameter of a single yarn is 3 to 7 μm, preferably 3 to 6 μm, and the cross-sectional shape is a cocoon shape. It is preferable to use carbon fibers that are Here, the carbon fiber having a substantially perfect circular cross-sectional shape refers to a carbon fiber having a ratio of the major axis to the minor axis of the single yarn of 0.7 or more.

In the present invention, the prepreg is set at 130 ° C.
The cured resin obtained by curing for 2 hours has a 0-degree tensile modulus of 230 GPa or more, a 0-degree interlaminar shear strength of 60 MPa or more, a board end peel strength of 110 MPa or more, and a 90-degree tensile strength of 35 MPa or more. preferable. When the prepreg is out of the above range, when the prepreg is applied to a bias material of a golf shaft or a 0 degree material of a fishing rod, microcracks and peeling occur between layers made of the prepreg, and static mechanical strength characteristics such as compressive strength and tensile strength. In addition, impact resistance, which is a dynamic mechanical strength characteristic, may be reduced. Here, the 0-degree tensile modulus is 330 GPa, the 0-degree interlaminar shear strength is 90 MPa, the plate edge peel strength is 260 MPa,
The 90-degree tensile strength is 60 MPa, which is often sufficient for achieving the effects of the present invention.

Further, in the present invention, the prepreg comprises 1
The cured resin obtained by curing at 30 ° C. for 2 hours has a 0 ° tensile elastic modulus of 160 GPa or more and a 0 ° interlayer shear strength of 75 M
Pa or more, plate edge peel strength is 150 MPa or more, and 90
The tensile strength is preferably 55 MPa or more. When the prepreg is out of the range, when the prepreg is applied to a straight material of a golf shaft or a 90-degree material of a fishing rod,
Microcracks and peeling may occur between layers of the prepreg, and the impact resistance, which is not only static mechanical strength characteristics such as compressive strength and tensile strength but also dynamic mechanical strength characteristics, may be reduced. Here, the 0 degree tensile modulus is 250 GP.
a, 0 degree interlayer shear strength is 95MPa, board edge peel strength is 3
00MPa and 90 degree tensile strength are 80MPa, respectively, and if they are each, it is often sufficient to achieve the effects of the present invention.

Furthermore, in the present invention, the prepreg is
A molded plate obtained by curing at 130 ° C. for 2 hours has a 0 ° tensile elastic modulus of 130 GPa or more and a 0 ° interlayer shear strength of 80 MPa.
a, the plate edge peel strength is preferably 270 MPa or more, and the 90 ° tensile strength is preferably 75 MPa or more. Outside of this range, prepregs may be used for aircraft primary structural materials,
When applied to general industrial applications such as automotive body parts, CNG tanks, drive shafts, etc., microcracks and peeling occur between layers made of prepreg, not only static mechanical strength characteristics such as compressive strength and tensile strength, but also dynamic Impact resistance, which is a high mechanical strength characteristic, may be reduced. here,
0 degree tensile modulus is 220 GPa, 0 degree interlayer shear strength is 1
10 MPa, the peel strength at the edge of the plate is 500 MPa, and the tensile strength at 90 ° is 100 MPa, which is often sufficient for achieving the effects of the present invention.

In the present invention, when the prepreg is applied to a tubular body such as a golf shaft or a fishing rod, the crystal size Lc of the carbon net plane is in the range of 10 to 35 angstroms, and the prepreg is cured at 130 ° C. for 2 hours. It is preferable to use a prepreg in which the cured resin obtained by the above method has a 90 ° tensile strength of 60 MPa or more. Thereby, in the obtained molded body, not only static mechanical strength characteristics such as compressive strength and tensile strength but also dynamic mechanical strength characteristics such as impact resistance can be enhanced.

The 90-degree tensile strength of about 100 MPa is often sufficient for achieving the effects of the present invention.

Hereinafter, taking acrylic carbon fiber as an example,
The method for producing carbon fibers according to the present invention will be described in detail.

As the polymer component, 95 mol% or more,
Preferably 98% by mole or more of acrylonitrile and 5% by mole or less, preferably 2% by mole or less of flame resistance are promoted,
A copolymer which is copolymerizable with acrylonitrile and has a flame retardant component promoted is preferably used. It is preferable to use a vinyl group-containing compound (hereinafter, referred to as a vinyl monomer) for the flame retardant component. Specific examples of the vinyl monomer include acrylic acid, methacrylic acid, and itaconic acid. Also, part or all of the copolymer, acrylic acid neutralized with ammonia, methacrylic acid,
Or a copolymer comprising an ammonium salt of itaconic acid,
It is more preferably used to enhance the effect of promoting flame resistance. In addition, as a method for polymerizing the polymer component, a solution polymerization method, a suspension polymerization method, an emulsion polymerization method, and the like can be applied as usual.

The spinning stock solution comprising the polymer component is spun into a yarn by a wet spinning method, a dry-wet spinning method, a dry spinning method, or a melt spinning method. Among them, a wet spinning method in which high strength yarn is easily obtained Alternatively, a dry-wet spinning method can be preferably applied. Here, as the solvent used for the spinning dope, a conventionally known organic or inorganic solvent can be used, but an organic solvent is preferably used. Specifically, dimethyl sulfoxide, dimethylformamide, dimethylacetamide and the like can be mentioned. If a concentrated aqueous solution of an inorganic salt such as an aqueous solution of nitric acid, an aqueous solution of rhodan soda, or an aqueous solution of zinc chloride is used as a solvent for the spinning solution, carbon fibers having a desired surface roughness may not be obtained. After spinning, the fiber is further subjected to a thread-forming process such as washing with water, drawing, drying, and application of an oil agent to obtain an acrylic precursor fiber.

Subsequently, the precursor fiber is subjected to oxidization. Here, the precursor fiber is used in view of securing productivity.
The single fiber fineness is 0.3 to 1.5 d (d: denier), preferably 0.5 to 1.3 d, more preferably 0.6 to 1.
1d is preferred. The number of single fibers per one thread of the precursor fiber is 1,000 to 50,000, preferably 6,000 to 48,000, more preferably 12,000.
The number is preferably up to 30,000.

In the flame-proofing step, the stretching ratio is set to 0.85 to 1.
It is preferable to make it flame-resistant as 1. The draw ratio is set to 0.87 to 0.5 to suppress burn unevenness as a yarn bundle.
94 is more preferred. If it is less than 0.85, the so-called processability decreases, and if it exceeds 1.1, diffusion of oxygen into the yarn is hindered, and burn unevenness at the center of the yarn may become remarkable.

[0131] The flame resistance is preferably set at a temperature of 200 to 300 ° C. Setting the temperature at 10 to 20 ° C lower than the temperature at which the yarn breaks due to the heat storage of the reaction heat reduces the cost and reduces the carbon fiber. It is preferable from the viewpoint of improving characteristics. The degree of progress of flame resistance can be observed by the flame shrinkage retention measured by the method described later for the flame resistant yarn obtained.

In the present invention, the flame resistance is preferably adjusted so that the flame shrinkage retention is 70 to 90%, preferably 74 to 86%, more preferably 76 to 84%.

From the viewpoint of improving the productivity and the properties of the carbon fiber, the flame resistance is preferably from 10 to 100 minutes, preferably from 30 to 100 minutes.
It is good to do it for 60 minutes. This oxidization time refers to the total time during which the yarn stays in the oxidization furnace. If the time is less than 10 minutes, the burn unevenness may be remarkable on the yarn, and if it exceeds 100 minutes, the productivity may be reduced.

[0134] In this way, the precursor fiber is oxidized into so-called oxidized fiber and then carbonized in the subsequent carbonization step to obtain carbon fiber having desired characteristics.

In the carbonization step, 300 to 300
Precarbonization at 900 ° C. The stretching ratio in the preliminary carbonization step is preferably 1.0 to 1.5, and more preferably 1.02 to 1.5.
1.3 to 1.3, more preferably 1.04 to 1.15.
The higher the stretching ratio, the more advantageous it is in exhibiting the elastic modulus, but if it exceeds 1.5, the processability may be significantly reduced.

Further, in an inert atmosphere, 900 to 1600
° C, preferably 1100 to 1500 ° C, more preferably 1200 to 1500 ° C. Below 900 ° C,
The moisture content contained in the obtained carbon fiber may be excessive. On the other hand, when the temperature exceeds 1600 ° C., crystal growth becomes remarkable inside the fiber, and the compressive strength and adhesiveness of the obtained carbon fiber may decrease.

The heating rate of the furnace and the processing time in the carbonization step can be appropriately selected in consideration of the characteristics required for the carbon fiber and the required cost. At this time, 300-500 ° C
And the temperature rising rate in the range of 1000 to 1200 ° C. is preferably 500 ° C./min or less, more preferably 300 ° C./min.
It is advantageous to obtain a fine carbon fiber having few internal defects such as voids in order to obtain a minute carbon fiber. In addition, it is preferable to shorten the carbonization treatment time as much as possible within a range in which the degree of carbonization does not matter, from the viewpoint of reducing required costs.

In the present invention, if necessary, carbon fibers may be heated in an inert atmosphere at 2000 to 3300 ° C., preferably 2000 to 3000 ° C., more preferably 2000 to 3000 ° C.
It may be graphitized at 2800 ° C.

The carbon fiber thus obtained is subjected to electrolytic oxidation treatment after carbonization, or to oxidation treatment in a gas phase or a liquid phase, so that the O / C, COOH / C, and N / C are in specific ranges. Carbon fiber is easily obtained.

Either acidic or alkaline aqueous solution can be used as the electrolytic solution for the electrolytic oxidation treatment.

As the electrolyte of the acidic aqueous solution, those exhibiting acidity when dissolved in water are preferable, and specific examples thereof include inorganic acids such as sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid, boric acid, and carbonic acid, acetic acid, butyric acid, and the like.
Organic acids such as oxalic acid, acrylic acid, and maleic acid, or inorganic salts such as ammonium sulfate and ammonium hydrogen sulfate can be used. Among them, sulfuric acid and nitric acid exhibiting strong acidity can be preferably used.

As the electrolyte of the alkaline aqueous solution, those exhibiting alkalinity when dissolved in water are preferable, and specifically, hydroxides such as sodium hydroxide, potassium hydroxide, barium hydroxide, ammonia, sodium carbonate, and the like. Inorganic salts such as sodium hydrogen carbonate, inorganic salts such as sodium acetate and sodium benzoate, and further, potassium salts, barium salts, other metal salts, and organic compounds such as ammonium salts and hydrazine can be used. Among them, an alkali metal which does not interfere with the curing reaction with the epoxy resin composition or an inorganic salt containing no ammonium ion can be preferably used. Specifically, it is preferable to use ammonium hydrogen carbonate, ammonium carbonate, a tetraalkylammonium hydroxide salt, or the like, or a mixture thereof. In particular, it is preferable to use ammonium bicarbonate, ammonium carbonate, tetraalkylammonium hydroxide or the like which has the effect of increasing the N / C.

The concentration of the electrolytic solution in the electrolytic oxidation treatment is from 0.01 to
The concentration is preferably 5 mol / l, more preferably 0.1 to 1 mol / l. The temperature of the electrolytic solution is 0 to 10
0 ° C., preferably 20 to 25 around room temperature.
℃ is good.

The amount of electricity required for the electrolytic oxidation treatment is preferably optimized in accordance with the degree of carbonization of the carbon fiber. However, the reduction in the tensile strength of the carbon fiber is suppressed, and the crystallinity in the surface layer is reduced. From the viewpoint of increasing the number of properties, the electrolytic oxidation treatment is preferably performed in a plurality of times by minimizing the amount of electricity per treatment and providing a plurality of electrolytic baths. Specifically, the amount of electricity is preferably 1 coulomb / g tank (1 g of carbon fiber, the number of coulombs per tank) to 40 coulomb / g tank.

As the energization method, either direct energization in which the carbon fiber is brought into direct contact with the electrode roller and energization, or indirect energization in which the carbon fiber and the electrode are energized via an electrolytic solution can be employed. In order to increase the tensile strength of the carbon fiber, it is preferable to use indirect energization in which the yarn is fluffed during the electrolytic oxidation treatment and the electric spark is suppressed.

After the electrolytic treatment, it is preferable to wash and dry. At this time, in order to improve the affinity and adhesiveness with the epoxy resin composition, it is desirable to dry at a temperature as low as possible so that the functional group present on the surface layer of the carbon fiber is not thermally decomposed. Drying temperature is 180-2
The temperature is preferably 50 ° C., and more preferably 180 to 210 ° C.

The carbon fiber thus obtained can be further subjected to a sizing treatment so that the fiber bundle has a convergence property and the affinity with the matrix resin can be improved.

The composite material according to the present invention can be produced by a conventionally known method. Specifically, as a method particularly suitable for the production of sports members such as golf shafts, fishing rods, rackets, etc., a prepreg in which an epoxy resin composition is impregnated into reinforcing fibers is prepared, laminated, heated, and cured. Then, a method of obtaining a composite material is employed.

The prepreg is prepared by dissolving the epoxy resin composition in a solvent such as methyl ethyl ketone or methanol to reduce the viscosity, thereby impregnating the reinforcing fibers, or by heating to reduce the viscosity to form the reinforcing fibers. It is manufactured by a method such as a hot melt method of impregnation.

In the wet method, a prepreg is obtained by immersing a reinforcing fiber in a liquid comprising an epoxy resin composition, pulling it up, and evaporating a solvent using an oven or the like.

In the hot melt method, the epoxy resin composition whose viscosity has been reduced by heating is directly impregnated into the reinforcing fibers, or a film in which the epoxy resin composition is coated on release paper or the like is prepared. The prepreg is obtained by impregnating the resin by laminating the films from both sides or one side and applying heat and pressure. This hot melt method is preferable because no solvent remains in the prepreg.

The form and arrangement of the reinforcing fibers in the prepreg are not particularly limited, and may be, for example, long fibers aligned in one direction, a single tow, a woven fabric, a mat, a knit, a braid, or the like.

The composite material can be produced by, for example, a method of laminating a prepreg, heating the resin while applying pressure to the laminate, and curing and molding the resin.

The method of applying heat and pressure includes a press molding method, an autoclave molding method, a bagging molding method, a wrapping tape method, an internal pressure molding method, and the like. Particularly, for sports goods, the wrapping tape method and the internal pressure molding method are used. It is preferably applied.

In the present invention, a wrapping tape method can be preferably used for producing a rod-shaped body such as a golf shaft and a fishing rod. The wrapping tape method is a method in which a prepreg is wound around a core metal such as a mandrel to form a cylindrical molded body. Specifically, wrapping a prepreg around a mandrel, wrapping a wrapping tape made of a thermoplastic resin film around the outside of the prepreg for fixing the prepreg and applying pressure, heating the resin in an oven and curing the resin, This is a method of removing gold and forming a cylindrical molded body.

In producing a rod-shaped body such as a golf shaft and a fishing rod, an internal pressure molding method can be preferably applied. The internal pressure molding method is a method in which a preform in which a prepreg is wound around an internal pressure applying body such as a tube of a thermoplastic resin is set in a mold, and then a high pressure gas is introduced into the internal pressure applying body to apply pressure, and at the same time, the mold is used. Is a method of heating and molding.
The method is preferably applied when molding a complicated shape such as a golf shaft, a bat, a racket such as tennis or badminton.

By using the epoxy resin composition of the present invention, various composite materials can be produced by a method without using a prepreg. Specifically, hand lay-up method, filament winding method, pultrusion method, resin injection method
The composite material can also be manufactured by a molding method such as a molding method, a resin transfer molding method, or the like. In these methods, a method of preparing an epoxy resin composition by mixing two liquids of a main agent composed of an epoxy resin and a curing agent immediately before use is preferably applied.

[0158]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments. The following methods were used for measuring the physical properties of the cured resin, preparing the prepreg, preparing the cylindrical composite material (tubular body), measuring the physical properties of the cylindrical composite material, preparing the unidirectional composite material, and measuring the physical properties of the unidirectional composite material. All the physical property measurements were performed in an environment at a temperature of 23 ° C. and a relative humidity of 50%. (1) Measurement of physical properties of cured resin (plate) Flexural modulus, 3-point bending amount The epoxy resin composition is heated to 80 ° C., poured into a mold, heated in a hot air dryer at 135 ° C. for 2 hours, and cured to form a cured resin product having a thickness of 2 mm (molding). Plate). Next, a test piece having a width of 10 mm and a length of 60 mm was cut out from the molded plate, and a test piece was cut at a test speed of 2.5 mm and a fulcrum distance of 32 mm.
A point bending test was performed, and a bending elastic modulus and a three-point bending amount were determined in accordance with JIS K7203. B. Tensile elongation JIS K
According to 7113, a small 1 (1/2) type test piece was cut out, and the tensile elongation was determined. C. Measurement of Elastic Modulus in Rubber State From a molded plate prepared in the same manner as in A, SACMA SR
According to M18R-94, the elastic modulus G ′ in a rubber state was determined by a DMA method. In the G ′ curve, the elastic modulus value at the intersection of the line extending the linear portion of the glass transition region and the line extending the linear portion of the rubber state region is defined as the elastic modulus G ′ in the rubber state,
It was used as an index of plastic deformability. Here, Rheometric Scien
The measurement was performed at a temperature rising rate of 5 ° C./min and a frequency of 1 Hz using a viscoelasticity measurement system expansion type “ARES” manufactured by Tific. (2) Measurement of crystal size Lc of carbon network plane by wide-angle X-ray diffraction Preparation of Measurement Sample A test piece having a length of 4 cm was cut out from a molded plate prepared in the same manner as A in the above section (1), and was solidified with a mold and a collodion-alcohol solution to form a prism and obtain a measurement sample. B. Measurement conditions X-ray source: CuKα (using Ni filter) Output: 40 kV, 20 mA Measurement of crystal size Lc The crystal size Lc was calculated from the half width of the peak of the plane index (002) obtained by the transmission method using the following Scherrer equation. Lc (hkl) = Kλ / β ₀ cos θ _B where Lc (hkl): average size of microcrystal in the direction perpendicular to the (hkl) plane K: 1.0, λ: wavelength of X-ray, β ₀ : (Β _E2 −β ₁₂ ) _1/2 β _E : Apparent half width (measured value), β ₁₂ : 1.05 × 1
0 ^-2 rad. θ _B : Bragg angle (3) Preparation of prepreg The epoxy resin composition was applied on release paper using a reverse roll coater to prepare a resin film. Next, two resin films are stacked on both sides of carbon fiber on carbon fiber trading card (registered trademark, manufactured by Toray Industries, Inc.) arranged in one direction in a sheet shape, and heated and pressed to impregnate the resin. A unidirectional prepreg having a fiber weight of 125 g / m ² and a resin weight fraction of 24% by weight was prepared. (4) Preparation of Cylindrical Composite Material According to the following procedures (a) to (e), it has a laminated configuration of [0 ／ ₃ / ± 45 ゜₃ ] with respect to the cylinder axis direction, and has an inner diameter of 6.3.
Two types of cylindrical composite materials, mm and 10 mm, were made.
The mandrels have a diameter of 6.3 mm and 10 mm, respectively.
A stainless steel round bar (each having a length of 1000 mm) was used. (A) A unidirectional prepreg is formed by using a unidirectional prepreg having a length of 800 mm × width 68 mm for a mandrel having a diameter of 6.3 mm and a mandrel having a diameter of 10 mm so that the direction of the reinforcing fiber is 45 degrees with respect to the mandrel axial direction. Height 80
A unidirectional prepreg of 0 mm × 103 mm in width was used.
These two sheets are crossed so that the fiber directions cross each other, and the mandrel having a diameter of 6.3 mm in the transverse direction has a diameter of 10 mm and a diameter of 1 mm.
In the case of a 0 mm mandrel, they were staggered by 16 mm (corresponding to a half circumference of the mandrel) and bonded. (B) The bonded prepreg was wound around the release-treated mandrel so that the longitudinal direction of the prepreg and the axial direction of the mandrel coincided. (C) On the prepreg, a mandrel with a diameter of 6.3 mm is 800 m long so that the direction of the fiber is vertical.
mx 77 mm wide, 80 mm long for a 10 mm diameter mandrel
A rectangular cutout of 0 mm x 112 mm was wound so that the longitudinal direction of the prepreg coincided with the axial direction of the mandrel. (D) A wrapping tape (heat-resistant film tape) was wrapped and heated at 130 ° C. for 2 hours in a curing furnace to form a molding. (E) After molding, the mandrel was pulled out and the wrapping tape was removed to obtain a cylindrical composite material. (5) Measurement of physical properties of cylindrical composite material Bending strength Using a cylindrical composite material with an inner diameter of 10 mm, "Certification Standards and Standard Confirmation Methods for Shafts for Golf Clubs" (Edited by the Japan Product Safety Association, approved by the Minister of International Trade and Industry No. 5, 2087, 1993)
The bending fracture load was measured based on the three-point bending test method described in (1), and the load value was used as the bending strength. Here, the distance between the fulcrums was 300 mm, and the test speed was 5 mm / min.

B. Torsion strength A 400 mm long test piece is cut out from a cylindrical composite material having an inner diameter of 10 mm, and "Certification criteria and standards confirmation method for golf club shafts" (edited by the Japan Society for Product Safety, approved by the Minister of International Trade and Industry, No. 2087, 1993) Follow the method described in
A torsion test was performed. The test piece gauge length is 300 mm,
50 mm at both ends of the test piece were gripped by a fixing jig. The torsional strength was determined by the following equation.

B. Torsion strength (N · m · deg) = torque torque (N · m) × torsion angle at break (deg) Crushing strength A test piece having a length of 15 mm was cut out from a cylindrical composite material having an inner diameter of 10 mm, and was broken by applying a compressive load in the radial direction of the cylinder via a stainless steel plate, and the load at the time of breaking was defined as the crushing strength. Here, the test speed was 5 mm / min.

D. Charpy impact fracture strength A Charpy impact test was performed according to the method described in JIS K7077 except that the cylindrical composite material was used for the test piece and the distance between the fulcrums was 40 mm. 6.3m inside diameter
A test piece having a length of 90 mm was cut out from a cylindrical composite material having a length of 40 m, a distance between supporting points was 40 mm, and a hammer swing angle was 135
An impact was applied from a direction perpendicular to the cylinder axis direction at a weight of 300 kg · cm, the maximum impact load was measured, and the load value was defined as the Charpy impact breaking strength. (6) Manufacture of unidirectional composite material A predetermined number of unidirectional prepregs manufactured by the method described in the above item (3) are laminated so that the directions of the reinforcing fibers are the same.
135 ° C, pressure 290 Pa using an autoclave
For 2 hours to cure by heating and pressing to produce a one-way composite material. (7) Measurement of physical properties of one-way composite material A. 90 degree tensile strength, 90 degree tensile elongation From a unidirectional composite material obtained by laminating 22 unidirectional prepregs, a width of 25.4 m according to ASTM D3039.
A test piece having a length of m and a length of 38.1 mm was prepared and subjected to a tensile test to measure 90 ° tensile elongation and 90 ° tensile strength.

B. 0 degree interlaminar shear strength (ILSS) From a unidirectional composite material obtained by laminating 22 unidirectional prepregs, according to ASTM D2344, a width of 6.4 mm,
A test piece having a length of 14 mm was prepared and subjected to a three-point bending test.
The 0-degree interlaminar shear strength was measured. (8) Preparation of Sample for Peeling Edge Strength (EDS) Measurement Ten unidirectional prepregs prepared by the method described in the above section (3) are laminated to form a laminated plate of [± 25 / ± 25/90] _S configuration. did. The thickness of this molded plate was 1 mm. (9) Measurement of board edge peel strength (EDS) Width (90 degree direction) from the laminate obtained in the above section (8)
A strip test piece having a length of 25 mm and a length (0 degree direction) of 300 mm was cut out. A diamond cutter with a blade grain size of # 170 is used for cutting, and the peripheral speed of the blade is 180.
0 m / min and the feed rate were 70 mm / min. A tensile force was applied to this test piece from the 0 degree direction at a grip distance of 200 mm, and the plate edge peel strength (EDS) was measured. (10) Measurement of Tensile Strength and Tensile Elastic Modulus of Carbon Fiber The carbon fiber to be measured is manufactured by Union Carbide Co., Ltd.
Bakelite (registered trademark) ERL-4221 1000
g (100 parts by weight), a resin composition obtained by mixing 30 g (3 parts by weight) of boron trifluoride monoethylamine (BF ₃ .MEA) and 40 g (4 parts by weight) of acetone,
Next, the mixture was heated at 130 ° C. for 30 minutes and cured to obtain a resin-impregnated strand. Resin-impregnated strand test method (JIS
R7601) to determine the tensile strength and tensile modulus. (11) Measurement of tensile elongation of carbon fiber Measured according to JIS R7601.

Hereinafter, examples and comparative examples will be described.
All parts described in Examples and Comparative Examples represent parts by weight.
The results of Examples and Comparative Examples are summarized in Tables 1 to 4. (12) Measurement of Functional Group Amount on Carbon Fiber Surface Surface specific oxygen concentration O / C Surface specific oxygen concentration O / C was determined by X-ray photoelectron spectroscopy according to the following procedure.

First, a sizing agent or the like was removed from the carbon fiber bundle to be measured with a solvent, cut to an appropriate length, spread on a stainless steel sample support, and measured under the following conditions.

[0165] - photoelectron escape angle: 90 ° · X-ray source: MgKarufa1,2-sample chamber vacuum: 1 × 10 ^-8 Torr Next, for the correction of the peak due to the measurement time of the charging, the main of C _1S B. Peak binding energy value E. FIG. 284.6 eV
I adjusted to.

Next, the C _1s peak area [O _1s ] is 28
A linear base line was drawn in the range of 2 to 296 eV, and the O _1s peak area [C _1s ] was obtained by drawing a linear base line in the range of 528 to 540 eV.

The surface specific oxygen concentration O / C is calculated as_1speak
Area [O_1s], C_1sPeak area [C _1s] Ratio and apparatus
From the intrinsic sensitivity correction value, it was obtained by the following equation.

O / C = ([O _1s ] / [C _1s ]) / (sensitivity correction value) In this case, as a measuring device, E / C manufactured by Shimadzu Corp.
Using SCA-750, the sensitivity correction value unique to the device was set to 2.85. (Examples 1 to 8) As the reinforcing fibers, carbon fibers produced by the following method were used.

Using a copolymer consisting of 99.4% of acrylonitrile and 0.6 mol% of methacrylic acid, a single fiber denier of 0.7 d and a filament number of 120 were obtained by wet spinning.
Acrylic precursor fiber No. 00 was obtained.

This precursor fiber is heated at 240 to 280 ° C. in air.
After heating at a draw ratio of 1.05 to convert to oxidized fiber and heating at a draw rate of 1.10 in a nitrogen atmosphere at a rate of 200 ° C./min in a temperature range of 300 to 900 ° C. It was fired to 1400 ° C. to advance carbonization. The basis weight of the obtained carbon fiber was 0.80 g / m, and the specific gravity was 1.80.

Next, electrolytic oxidation treatment was performed using a 0.1 mol / l aqueous solution of sulfuric acid as an electrolytic solution in a tank of 5 coulombs / g. Next, the carbon fiber after the electrolytic oxidation treatment was washed with water and dried in air at 150 ° C.

Table 1 shows various strength properties of the carbon fibers thus obtained.

A resin composition shown in Table 1 was prepared containing at least 70% by weight of a bifunctional epoxy resin with respect to all epoxy resins. Table 1 shows the results of measuring the strength properties of the cured resin according to the method (1).

Using the carbon fiber and the epoxy resin composition, a unidirectional prepreg is prepared according to the method (3), and these are laminated and cured according to the method (4) to form a cylindrical composite material. Table 2 shows the results of measurement of various strength properties. (Example 9) All epoxy resins consist of a bifunctional epoxy resin, and 75 wt% of a high molecular weight bifunctional epoxy resin having a molecular weight of 450 or more (Epicoat 1001, registered trademark) based on 100 wt% of the total epoxy resin. The resin compositions shown in Table 1 were prepared. Table 1 shows the results of measuring the strength characteristics of the cured resin.

A one-way prepreg was prepared from the epoxy resin composition according to the method of Example 1, and these were laminated.
Table 2 shows the results of measurement of various strength physical properties after curing to produce a cylindrical composite material. Comparative Example 1 65% by weight of a bifunctional epoxy resin and a polyfunctional epoxy resin (Epicoat 15)
4, a resin composition shown in Table 3 consisting of 35% by weight was prepared. Table 3 shows the results of measuring the strength properties of the cured resin.

A one-way prepreg was prepared from the epoxy resin composition according to the method of Example 1, and these were laminated.
Table 4 shows the results of measurement of various strength physical properties by curing to produce a cylindrical composite material. (Comparative Example 2) Denacol EX-201 (registered trademark), which is a bifunctional epoxy resin having a rigid skeleton, is 17% by weight of a low-molecular weight bifunctional epoxy resin (Epicoat 828, registered trademark) based on all epoxy resins. , Epicoat YX40
00H (registered trademark), Epicron 152 (registered trademark)
The resin compositions shown in Table 3 were prepared, each consisting of 20% by weight, 33% by weight, and 30% by weight. Table 3 shows the results of measuring the strength properties of the cured resin.

According to the method of Example 1, a unidirectional prepreg was prepared from the epoxy resin composition, and these were laminated.
Table 4 shows the results of measurement of various strength physical properties by curing to produce a cylindrical composite material. Comparative Example 3 Low-molecular weight bifunctional epoxy resin (Epicoat 828, registered trademark) was 60% by weight, and high molecular weight bifunctional epoxy resin having a molecular weight of 450 or more (Epicoat 1001, registered trademark) was 10% of all epoxy resins. A resin composition shown in Table 3 was prepared by weight%. Table 3 shows the results of measuring the strength properties of the cured resin.

A one-way prepreg was prepared from the epoxy resin composition according to the method of Example 1, and these were laminated.
Table 4 shows the results of measurement of various strength physical properties by curing to produce a cylindrical composite material. (Example 10) As reinforcing fibers, carbon fibers produced by the following method were used.

Using a copolymer consisting of 99.4% of acrylonitrile and 0.6 mol% of methacrylic acid, single fiber denier 1.0d, filament number 12
000 acrylic precursor fibers were obtained.

This precursor fiber is heated at 240 to 280 ° C. in air.
After heating at a draw ratio of 1.05 to convert to oxidized fiber and heating at a draw rate of 1.10 in a nitrogen atmosphere at a rate of 200 ° C./min in a temperature range of 300 to 900 ° C. It was fired to 1400 ° C. to advance carbonization. The basis weight of the obtained carbon fiber was 0.58 g / m, and the specific gravity was 1.81.

Next, electrolytic oxidation treatment was performed using a 0.1 mol / l aqueous solution of sulfuric acid as an electrolytic solution in an electric quantity 5 coulomb / g tank. Next, the carbon fiber after the electrolytic oxidation treatment was washed with water and dried in air at 150 ° C.

Table 5 shows various strength physical properties of the carbon fibers thus obtained.

Using the carbon fiber and the same epoxy resin composition as in Example 1, a unidirectional prepreg was prepared, and these were laminated and cured to prepare a cylindrical composite material. Shown in (Example 11) The same carbon fiber as in Example 10 and Example 2
A unidirectional prepreg was prepared from the same epoxy resin composition as described above, and these were laminated and cured to produce a cylindrical composite material. The results of measuring various physical properties are shown in Table 6. (Example 12) The same carbon fiber as in Example 10 and Example 3
A unidirectional prepreg was prepared from the same epoxy resin composition as described above, and these were laminated and cured to produce a cylindrical composite material. The results of measuring various physical properties are shown in Table 6. (Example 13) The same carbon fiber as in Example 10 and Example 4
A unidirectional prepreg was prepared from the same epoxy resin composition as described above, and these were laminated and cured to produce a cylindrical composite material. The results of measuring various physical properties are shown in Table 6. (Example 14) As reinforcing fibers, carbon fibers produced by the following method were used.

Using a copolymer consisting of 99.4% of acrylonitrile and 0.6 mol% of methacrylic acid, a single fiber denier of 1.0 d and a filament count of 120 were obtained by wet spinning.
Acrylic precursor fiber No. 00 was obtained.

The precursor fiber is heated in air at 240 to 280 ° C.
After heating at a draw ratio of 1.05 to convert to oxidized fiber and heating at a draw rate of 1.10 in a nitrogen atmosphere at a rate of 200 ° C./min in a temperature range of 300 to 900 ° C. At 1450 ° C. to advance carbonization. The basis weight of the obtained carbon fiber was 0.42 g / m, and the specific gravity was 1.79.

Next, electrolytic oxidation treatment was performed using a 0.1 mol / l sulfuric acid aqueous solution as an electrolytic solution in an electric quantity 5 coulomb / g tank. Next, the carbon fiber after the electrolytic oxidation treatment was washed with water and dried in air at 150 ° C.

Table 5 shows various physical properties of the carbon fibers thus obtained.

A unidirectional prepreg was prepared from the carbon fiber and the same epoxy resin composition as in Example 5, and these were laminated and cured to produce a cylindrical composite material. Shown in (Example 15) As the reinforcing fiber, a carbon fiber manufactured by the following method was used.

Using a copolymer consisting of 99.4% of acrylonitrile and 0.6 mol% of methacrylic acid, single fiber denier 1.0d, filament number 12
000 acrylic precursor fibers were obtained.

This precursor fiber is heated in air at 240 to 280 ° C.
After heating at a draw ratio of 1.05 to convert to oxidized fiber and heating at a draw rate of 1.10 in a nitrogen atmosphere at a rate of 200 ° C./min in a temperature range of 300 to 900 ° C. It was baked to 1800 ° C. to advance carbonization. The basis weight of the obtained carbon fiber was 0.60 g / m, and the specific gravity was 1.76.

Next, electrolytic oxidation treatment was performed using a 0.1 mol / l sulfuric acid aqueous solution as an electrolytic solution in an electric quantity 5 coulomb / g tank. Next, the carbon fiber after the electrolytic oxidation treatment was washed with water and dried in air at 150 ° C.

Table 5 shows various physical properties of the carbon fibers thus obtained.

A unidirectional prepreg was prepared from the carbon fiber and the same epoxy resin composition as in Example 2, and these were laminated and cured to prepare a cylindrical composite material. Shown in (Example 16) As the reinforcing fiber, a carbon fiber manufactured by the following method was used.

Using a copolymer consisting of 99.4% of acrylonitrile and 0.6 mol% of methacrylic acid, a single fiber denier of 0.9 d and a filament number of 12 were obtained by a dry-wet spinning method.
000 acrylic precursor fibers were obtained.

The precursor fiber is heated at 240 to 280 ° C. in air.
After heating at a draw ratio of 1.05 to convert to oxidized fiber and heating at a draw rate of 1.10 in a nitrogen atmosphere at a rate of 200 ° C./min in a temperature range of 300 to 900 ° C. To 2000 ° C. to advance carbonization. The basis weight of the obtained carbon fiber was 0.80 g / m, and the specific gravity was 1.76.

Next, electrolytic oxidation treatment was carried out using a 0.1 mol / l sulfuric acid aqueous solution as an electrolytic solution in an electric quantity 5 coulomb / g tank. Next, the carbon fiber after the electrolytic oxidation treatment was washed with water and dried in air at 150 ° C.

Table 5 shows various strength physical properties of the carbon fibers thus obtained.

Using the carbon fiber and the same epoxy resin composition as in Example 2, a unidirectional prepreg was prepared, and these were laminated and cured to prepare a cylindrical composite material. Shown in (Example 17) As the reinforcing fiber, a carbon fiber manufactured by the following method was used.

Using a copolymer consisting of 99.4% of acrylonitrile and 0.6 mol% of methacrylic acid, a single fiber denier of 0.7 d and a filament count of 120 were obtained by wet spinning.
Acrylic precursor fiber No. 00 was obtained.

This precursor fiber is heated at 240-280 ° C. in air.
After heating at a draw ratio of 1.05 to convert to oxidized fiber and heating at a draw rate of 1.10 in a nitrogen atmosphere at a rate of 200 ° C./min in a temperature range of 300 to 900 ° C. It was fired to 1400 ° C. to advance carbonization. The basis weight of the obtained carbon fiber was 0.45 g / m, and the specific gravity was 1.77.

Next, electrolytic oxidation treatment was performed using a sulfuric acid aqueous solution having a concentration of 0.1 mol / l as an electrolytic solution in an electric quantity 5 coulomb / g tank. Next, the carbon fiber after the electrolytic oxidation treatment was washed with water and dried in air at 150 ° C.

Table 7 shows various physical properties of the carbon fibers thus obtained.

A unidirectional prepreg was prepared from the carbon fiber and the same epoxy resin composition as in Example 1, and these were laminated and cured to produce a cylindrical composite material. Shown in (Comparative Example 4) As the reinforcing fiber, a carbon fiber manufactured by the following method was used.

Using a copolymer consisting of 99.4% of acrylonitrile and 0.6 mol% of methacrylic acid, a single fiber denier of 0.7 d and a filament count of 120 were obtained by a wet spinning method.
Acrylic precursor fiber No. 00 was obtained.

This precursor fiber is heated at 240 to 280 ° C. in air.
After heating at a draw ratio of 1.05 to convert to oxidized fiber and heating at a draw rate of 1.10 in a nitrogen atmosphere at a rate of 200 ° C./min in a temperature range of 300 to 900 ° C. It was fired to 1400 ° C. to advance carbonization. The basis weight of the obtained carbon fiber was 0.73 g / m, and the specific gravity was 1.80.

Next, electrolytic oxidation treatment was carried out using a sulfuric acid aqueous solution having a concentration of 0.1 mol / l as an electrolytic solution in an electric quantity of 5 coulomb / g. Next, the carbon fiber after the electrolytic oxidation treatment was washed with water and dried in air at 150 ° C.

Table 1 shows various strength physical properties of the carbon fibers thus obtained.

A resin composition shown in Table 1 was prepared containing at least 70% by weight of a bifunctional epoxy resin based on all epoxy resins. Table 1 shows the results of measuring the strength properties of the cured resin according to the method (1). (Example 17) Single fiber denier by dry-wet spinning method
0d, an acrylic precursor fiber having 12000 filaments was obtained. Next, a carbon fiber was obtained in the same manner as in Example 1 except that the firing temperature was 1350 ° C.

Table 9 shows various strength physical property values of the carbon fibers thus obtained.

A unidirectional prepreg was prepared from the carbon fiber and the same epoxy resin composition as in Example 1, and these were laminated and cured to produce a cylindrical composite material. Shown in (Example 18) Single fiber denier 1.0 by wet spinning
d. An acrylic precursor fiber having 12000 filaments was obtained. Next, a carbon fiber was obtained in the same manner as in Example 1 except that the firing temperature was 1300 ° C.

Table 9 shows various strength physical property values of the carbon fibers thus obtained.

A unidirectional prepreg was prepared from the carbon fiber and the same epoxy resin composition as in Example 5, and these were laminated and cured to produce a cylindrical composite material. Shown in (Example 19) Single fiber denier 1.0 by wet spinning
d. An acrylic precursor fiber having 12000 filaments was obtained. Next, a carbon fiber was obtained in the same manner as in Example 1 except that the firing temperature was 1350 ° C.

Table 9 shows various strength physical properties of the carbon fibers thus obtained.

A unidirectional prepreg was prepared from the carbon fiber and the same epoxy resin composition as in Example 4, and these were laminated and cured to produce a cylindrical composite material. Shown in (Example 20) A single fiber denier of 0.1 was obtained by a dry-wet spinning method.
7d, an acrylic precursor fiber having 12,000 filaments was obtained. Next, a carbon fiber was obtained in the same manner as in Example 1 except that the firing temperature was 1750 ° C.

Table 9 shows various physical properties of the carbon fibers thus obtained.

A unidirectional prepreg was prepared from the carbon fiber and the same epoxy resin composition as in Example 4, and these were laminated and cured to prepare a cylindrical composite material. Shown in (Example 21) Carbon fibers were obtained in the same manner as in Example 16 except that the surface treatment was performed using an aqueous solution of ammonium bicarbonate having a concentration of 2 mol / l as an electrolytic solution and electrolytic oxidizing treatment in an electric quantity of 35 coulomb / g. .

Table 9 shows various physical properties of the carbon fibers thus obtained.

A unidirectional prepreg was prepared from the carbon fiber and the same epoxy resin composition as in Example 4, and these were laminated and cured to produce a cylindrical composite material. Shown in (Example 22) As reinforcing fibers, carbon fibers produced by the following method were used.

Using a copolymer consisting of 99.4% of acrylonitrile and 0.6 mol% of methacrylic acid, single fiber denier 1.0d, filament number 12
000 acrylic precursor fibers were obtained.

This precursor fiber is heated at 240 to 280 ° C. in air.
After heating at a draw ratio of 1.05 to convert to oxidized fiber and heating at a draw rate of 1.10 in a nitrogen atmosphere at a rate of 200 ° C./min in a temperature range of 300 to 900 ° C. To 2000 ° C. to advance carbonization. The basis weight of the obtained carbon fiber was 0.80 g / m, and the specific gravity was 1.76.

Next, electrolytic oxidation treatment was carried out using a 0.1 mol / l sulfuric acid aqueous solution as an electrolytic solution in an electric quantity of 40 coulomb / g tank. Next, the carbon fiber after the electrolytic oxidation treatment was washed with water and dried in air at 200 ° C.

Table 9 shows various strength properties of the carbon fibers thus obtained.

A unidirectional prepreg was prepared from the carbon fiber and the same epoxy resin composition as in Example 1, and these were laminated and cured to produce a cylindrical composite material. Shown in (Example 23) A carbon fiber was obtained in the same manner as in Example 13 except that the drying temperature was changed to 400 ° C. As shown in Table 9, this carbon fiber had a low N / C of 0.003.

A unidirectional prepreg was prepared from the carbon fiber and the same epoxy resin composition as in Example 1, and these were laminated and cured to produce a cylindrical composite material. Shown in (Comparative Example 5) A unidirectional prepreg was prepared from the same carbon fiber as in Example 17 and the same epoxy resin composition as in Comparative Example 1, and these were laminated and cured to form a cylindrical composite material, and various strength properties were measured. Table 12 shows the results. (Comparative Example 6) A unidirectional prepreg was prepared from the same carbon fiber as in Example 18 and the same epoxy resin composition as in Comparative Example 1, and these were laminated and cured to prepare a cylindrical composite material, and various strength properties were measured. Table 12 shows the results. (Comparative Example 7) A unidirectional prepreg was prepared from the same carbon fiber as in Example 20 and the same epoxy resin composition as in Comparative Example 1, and these were laminated and cured to form a cylindrical composite material, and various strength properties were measured. Table 12 shows the results.

[0225]

[Table 1]

[0226]

[Table 2]

[0227]

[Table 3]

[0228]

[Table 4]

[0229]

[Table 5]

[0230]

[Table 6]

[0231]

[Table 7]

[0232]

[Table 8]

[0233]

[Table 9]

[0234]

[Table 10]

[0235]

[Table 11]

[0236]

[Table 12]

[0237]

According to the present invention, a resin composition having excellent adhesion between the reinforcing fibers and the matrix resin, and excellent tensile elongation and flexural modulus of the matrix resin can be obtained. A high-quality prepreg can be produced from this resin composition and a reinforced fiber woven fabric such as carbon fiber. Further, by laminating and molding this prepreg, a fiber-reinforced composite material having excellent mechanical strength properties can be produced. Can be.

The fiber reinforced composite material according to the present invention has excellent 0 degree compression strength and 0 degree interlaminar shear strength (ILSS). Such an effect is remarkable when the flexural modulus of the matrix resin is high. This is presumed to be because a matrix resin having a high flexural modulus has an effect of preventing Euler buckling of the reinforcing fibers.

The fiber-reinforced composite material according to the present invention has a non-fiber directional tensile strength, a bending strength, a torsional strength, a crushing strength, an in-plane shear strength, and a mode I measured by an End Notched Flexure method.
I It has excellent interlayer toughness. This is remarkable when the tensile elongation of the matrix resin is high. It is presumed that this is because a matrix resin having a high tensile elongation has the effect of preventing the propagation of microcracks due to local fiber breakage and the prevention of separation between the reinforcing fibers and the matrix resin.

The fiber reinforced composite material according to the present invention has excellent impact resistance typified by Charpy impact fracture strength.

The fiber reinforced composite material according to the present invention is suitably used for sports applications such as golf shafts, fishing rods, rackets for tennis, badminton, squash, etc., sticks for hockey, etc., and ski poles. In aerospace applications, primary structural materials such as wings, tails, floor beams, etc., secondary structural materials such as flaps, ailerons, cowls, fairings, interior materials, rocket motor cases, artificial satellite structural materials, etc. It is preferably used. In general industrial applications, structural materials for vehicles such as automobiles, ships, and railway vehicles, drive shafts, leaf springs, windmill blades, pressure vessels, flywheels, papermaking rollers, roofing materials, cables, reinforcing bars, repair reinforcing materials It is suitably used for civil engineering and building material applications.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat 参考 (Reference) C08L 63/00 C08L 63/00 Z (72) Inventor Hiroshi Takagishi 1515 Tsutsui, Matsu-machi, Matsumae-cho, Iyo-gun, Ehime Prefecture Toray Co., Ltd. Ehime Plant (72) Inventor Hiroki Oshito 1515 Otsutsui, Matsumae-cho, Iyo-gun, Ehime Prefecture F-term in Toray Co., Ltd. Ehime Plant (Reference) CD061 CD071 CK032 DA016 EL137 EN047 EN077 EN098 EN107 EN108 EN117 EN118 EP018 ER027 EV227 FA046 FD016 FD147 FD202 FD208 4J036 AA01 AC01 AC08 AD01 AF06 CA15 CB09 CB18 DB15 DB21 DC02 DC03 DC06 DC10 DC21 DC31 DD04 JA11

Claims (18)

[Claims] 1. The method according to claim 1, comprising an epoxy resin and a curing agent.
An epoxy resin composition having a tensile elongation of 8% or more of a cured resin obtained by curing at 30 ° C. for 2 hours is a carbon having a crystal size Lc of 5 to 40 angstroms on a carbon network plane determined by wide-angle X-ray diffraction. A prepreg impregnated with fibers. 2. The epoxy resin composition comprises a bifunctional epoxy resin, wherein the bifunctional epoxy resin is 70 to 100% by weight based on 100% by weight of the total epoxy resin in the epoxy resin composition. The prepreg according to claim 1, wherein 3. The epoxy resin composition comprises a high molecular weight bifunctional epoxy resin having an epoxy equivalent of 450 or more, wherein the high molecular weight bifunctional epoxy resin is a total bifunctional epoxy resin in the epoxy resin composition. The prepreg according to claim 2, wherein the amount is 15 to 70% by weight based on 100% by weight. 4. The prepreg according to claim 1, wherein the epoxy resin composition comprises the following component (A). (A) Compound having one functional group and one or more amide bonds capable of reacting with an epoxy resin or a curing agent in a molecule 5. The prepreg according to claim 4, wherein the amount of the component (A) is 0.5 to 15 parts by weight based on 100 parts by weight of the total epoxy resin. 6. A functional group capable of reacting with an epoxy resin or a curing agent in the component (A) includes a carboxyl group, a phenolic hydroxyl group, an amino group, a secondary amine structure, a mercapto group, an epoxy group, and a carbonyl group. The prepreg according to claim 4 or 5, wherein the prepreg is at least one selected from the group consisting of conjugated double bonds. 7. The prepreg according to claim 1, wherein the epoxy resin composition comprises the following component (B). (B) Polyester polyurethane having an aromatic ring in the molecule 8. The prepreg according to claim 7, wherein the amount of the component (B) is 1 to 15 parts by weight based on 100 parts by weight of the total epoxy resin. 9. The carbon fiber according to claim 1, wherein said surface specific oxygen concentration O / C measured by chemical modified X-ray photoelectron spectroscopy is 0.02 to 0.02.
The prepreg according to any one of claims 1 to 8, wherein the prepreg is 0.3. 10. The carbon fiber has a surface specific nitrogen concentration N / C of 0.02 as measured by chemically modified X-ray photoelectron spectroscopy.
The prepreg according to any one of claims 1 to 9, wherein 11. The epoxy resin composition according to claim 1, wherein
Deformation of three-point bending of molded plate obtained by curing over time is 10 to 2
The prepreg according to any one of claims 1 to 10, which is 5 mm. 12. The epoxy resin composition according to claim 1, wherein
The elastic modulus G ′ (MPa) of a rubber state in dynamic viscoelasticity at a measurement frequency of 0.5 Hz of a cured product obtained by time curing satisfies the following expression (1). Prepreg. 1 ≦ G ′ ≦ 8 (1) 13. The prepreg according to claim 1, wherein the carbon fiber has a tensile elongation of 1.1% or more. 14. The carbon fiber according to claim 1, wherein the diameter of the single yarn is 4 to 7 μm.
The prepreg according to any one of claims 1 to 13, wherein the prepreg is in a range of m and the cross-sectional shape of the carbon fiber is substantially a perfect circle. 15. The carbon fiber, wherein the single yarn has a diameter of 3 to 7 μm.
The prepreg according to any one of claims 1 to 13, wherein the prepreg is in a range of m and the cross-sectional shape of the carbon fiber is a cocoon shape. 16. The carbon fiber according to claim 1, wherein a tensile modulus E thereof and a crystal size Lc (angstrom) of a carbon network surface determined by wide-angle X-ray diffraction satisfy the following expression (3).
The prepreg according to any one of (1) to (15), Lc ≦ 0.14 × E-13 (3) 17. The carbon fiber, wherein the crystal size Lc of the carbon network plane is in the range of 10 to 35 angstroms, and 13
The prepreg according to any one of claims 1 to 16, wherein a 90-degree tensile strength of a molded plate obtained by curing at 0 ° C for 2 hours is 60 MPa or more. 18. A fiber-reinforced composite material obtained by heating and curing the prepreg according to claim 1.