JP2001049013A - Prepreg and carbon fiber reinforced composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin composition which cures to give a matrix resin excellent in adhesion to a reinforcing fiber, a prepreg using the composition and a carbon fiber reinforced composite material excellent in various properties obtained by using the prepreg. SOLUTION: A prepreg is obtained by impregnating a carbon fiber with an epoxy resin composition containing the following components (A), (B), (C) and (D), wherein the component (C) is dispersed with an average particle diameter of 10 μm or less in a carbon fiber reinforced composite material obtained by curing the prepreg. (A) an epoxy resin, (B) a curing agent, (C) a thermoplastic resin, and (D) a compound having a functional group capable of reacting with the epoxy resin or the curing agent and one or more amido bonds in the molecule.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a prepreg and a carbon fiber reinforced composite material suitable for sports use, aerospace use, and general industrial use.

More specifically, for example, aircraft, ships,
Various frames, pipes, and shafts in automobiles, bicycles, and other industrial machines such as pumps and brush cutters, and their curved disks, or golf club shafts, fishing rods, ski poles, badminton racket shafts,
Prepregs and carbon fiber reinforced composites that can be suitably used for tubular bodies such as tent posts, or various sports / leisure products such as skis, snowboards, golf club heads, etc., or materials for civil engineering and construction, and repair / reinforcement thereof It is about materials.

[0003]

2. Description of the Related Art A fiber-reinforced composite material using a prepreg composed of a reinforcing fiber and a matrix resin as an intermediate base material has excellent mechanical strength characteristics, and is especially used for sports applications, aerospace applications, and general industrial applications. Widely used for Particularly in sports applications, golf club shafts, fishing rods, rackets such as tennis and badminton, and sticks such as hockey can be cited as important applications.

[0004] Particularly in sports applications, carbon fibers are mainly used as reinforcing fibers, and epoxy resins are mainly used as matrix resins.

Various methods are used for producing a fiber-reinforced composite material, and a method using a prepreg, which is a sheet-like intermediate substrate in which a reinforcing fiber is impregnated with a matrix resin, is widely used. In this method, after laminating a plurality of prepregs, a molded article is obtained by heating.

A fiber reinforced composite material for sports,
Golf club shafts, fishing rods and the like are fields in which weight reduction is particularly required, but as a prerequisite for weight reduction, it is necessary to increase the strength of the material.

[0007] In order to cope with this, efforts have been made to improve the strength of reinforcing fibers, particularly carbon fibers, and many results have been obtained.

However, a precise analysis of the destruction phenomena of golf club shafts and fishing rods, especially of their lightweight varieties, has revealed that the strength of carbon fiber alone is not always sufficient.

A golf club shaft and a fishing rod are usually formed by winding several layers of a unidirectional prepreg in different directions and stacking them. When such a composite material breaks down, the composition of the material and how external force is applied (bending, twisting,
The fracture mode changes depending on the compression ring, etc., but either 0 degree (in the direction parallel to the reinforcing fiber) compression or 90%
Either of the failure modes in the degree (in the direction perpendicular to the reinforcing fibers) tensile is often the dominant factor, and in some cases, the failure mode due to shear is dominant.

[0010] Of these, the 0-degree compressive strength depends on the compressive strength of the reinforcing fiber, the adhesiveness between the reinforcing fiber and the matrix resin, and the elastic modulus of the matrix resin. Can be enhanced.

The 90-degree tensile strength depends on the tensile strength of the matrix resin and the adhesiveness between the reinforcing fiber and the matrix resin, and the higher these values, the higher the 90-degree tensile strength can be. Furthermore, the tensile strength of the matrix resin is
It can be improved by increasing the flexural modulus and tensile elongation of the matrix resin.

Therefore, in order to stably obtain a composite material having high strength characteristics irrespective of the composition of the material, it is extremely effective to enhance the adhesiveness between the reinforcing fiber and the matrix resin. Furthermore, increasing the adhesion between the reinforcing fibers and the matrix resin has the effect of increasing the shear strength of the composite material, and furthermore, not only these static strength properties, but also dynamic strength properties such as impact resistance. It is also known to have the effect of increasing

In order to enhance the adhesion between the reinforcing fiber and the matrix resin, surface treatment of the reinforcing fiber has been studied.
In the case of carbon fiber, electrolytic treatment and the like are known.

[0014] There is a limit in improving the adhesiveness only by treating the reinforcing fiber, and in order to meet the increasingly demanding physical property improvement of composite materials, a technique based on resin modification is required. Although it is conceivable, at present, for epoxy resins that are commonly used as matrix resins, as a method of improving the adhesion between the reinforcing fibers and the matrix resin by modifying the resin, a certain type of thermoplastic resin is blended. Although there is a finding that is effective,
At present it is not enough.

The fiber-reinforced composite material takes various shapes depending on the application. When the shape is a tubular body, strength characteristics such as tensile strength, compressive strength, bending strength, and torsional strength are emphasized, and these strength characteristics are enhanced. Efforts are being made for it.

In recent years, in the case of lightweight members, such as golf club shafts, having a limited degree of design freedom, in addition to the above-mentioned strength characteristics, the impact strength and crushing strength of a tubular body have been attracting attention. Since it is difficult to identify the factors for increasing these by various tests, it has been difficult to make improvements and to produce those having sufficient strength characteristics.

[0017]

SUMMARY OF THE INVENTION In view of the background of the prior art, the present invention provides a prepreg capable of obtaining a carbon fiber reinforced composite material excellent in various properties, and a carbon fiber reinforced composite material having such excellent properties. It is intended to provide a composite material.

More specifically, an object of the present invention is to solve the above-mentioned conventional problems and to provide a prepreg and a carbon fiber reinforced composite material having excellent properties, for example, crushing strength, impact strength while being excellent in bending strength and torsion strength. An object of the present invention is to provide a prepreg and a carbon fiber reinforced composite material capable of providing a golf club shaft having excellent strength.

[0019]

The present invention has the following arrangement to achieve the above-mentioned object. That is, a prepreg obtained by impregnating a carbon fiber with an epoxy resin composition containing the following components (A), (B), (C) and (D), wherein the component (C) comprises A prepreg characterized by being dispersed with an average particle size of 10 μm or less in a carbon fiber reinforced composite material obtained by curing, and a carbon fiber reinforced composite material obtained by curing the prepreg.

(A) Epoxy resin (B) Curing agent (C) Thermoplastic resin (D) Epoxy resin (A) or curing agent (B) in the molecule
Having one functional group and one or more amide bonds capable of reacting with

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors diligently studied the above-mentioned problems, and provided a prepreg and a carbon-fiber-reinforced composite material containing an epoxy resin composition comprising a carbon fiber and a specific compound as components. Were found to be solved all at once, and arrived at the present invention.

A golf club shaft generally has a straight layer in which reinforcing fibers are oriented in the shaft axis direction and a bias layer in which reinforcing fibers are oriented at 30 to 60 degrees with respect to the shaft axis direction.

When the fiber-reinforced composite material is a tubular body such as the golf club shaft, the crushing stress is mainly borne by the bias layer. At this time, various stresses such as tensile stress and compressive stress in the 0-degree direction, tensile stress in the 90-degree direction, compressive stress, shear stress, and peeling stress act on each unit layer of the bias layer. As a result of the study, it was found that shear stress tended to act strongly, and it was found that the use of a material having excellent shear strength for the bias layer increased the crushing strength as a tubular body such as a shaft. Was.

Further, since the straight layer also has a stress exchange action with the bias layer, it has been found that the crushing strength of the entire tubular body can be increased even when a material having high shear strength is used for the straight layer.

On the other hand, the strength characteristics against the instantaneously acting impact stress, that is, the impact strength, during the evaluation test, the stress acts on the straight layer and the bias layer in a complicated manner. It was difficult to determine the main factors for increasing the impact strength. Conventionally, it has been considered that the impact strength has a positive correlation with the bending strength, but it has been difficult to increase the impact strength even if a material having a high bending strength is used. However, in the case of a tubular body such as a golf club shaft, the impact strength has a positive correlation with the crushing strength. Therefore, it has been found that it is important to increase the shear strength in increasing the impact strength.

It has been found that by improving the shear strength, particularly the in-plane shear strength, of such a fiber-reinforced composite material, the crushing strength, the impact strength and the torsional strength are remarkably improved.

The in-plane shear strength S (MPa) of the carbon fiber reinforced composite material (hereinafter abbreviated as CFRP) varies depending on the tensile modulus E (GPa) of the carbon fiber and the matrix resin content Wr (% by weight). However, in general, the tendency tends to increase as the tensile modulus E (GPa) of the carbon fiber decreases and as the matrix resin content Wr increases.

C obtained by curing the prepreg of the present invention
FRP is designed to achieve high crushing strength and impact strength.
It is preferable that the matrix resin content Wr (% by weight), the tensile modulus E (GPa) of the carbon fiber, and the in-plane shear strength S (MPa) satisfy the following expressions (1) and (2). Here, the matrix resin content Wr is the content (% by weight) of the matrix resin obtained by curing the epoxy resin composition in CFRP.

S ≧ −205 × LOG (E) +610 (1) 15 ≦ Wr ≦ 40 (2) When the in-plane shear strength S of CFRP is small and does not satisfy the above equation (1), the crushing strength becomes small. Also, the rigidity against deformation stress is reduced, and the impact strength is also reduced.

Further, the tensile modulus E (GP
The in-plane shear strength S (MPa) of a) and CFRP preferably satisfies the following expression (3). Thereby, CFRP
In addition, better crushing strength and impact strength can be obtained.

S ≧ −205 × LOG (E) +620 (3) The prepreg of the present invention is formed by impregnating carbon fibers with an epoxy resin composition.

As the carbon fiber, specifically, an acrylic, pitch, rayon or other carbon fiber can be used.
Among them, an acrylic resin having a high tensile strength is preferable. As the form of the carbon fiber, twisted yarn, untwisted yarn, untwisted yarn and the like can be used, but untwisted yarn or untwisted yarn is preferable in consideration of the balance between the moldability and the strength characteristics of the composite material. The carbon fibers in the present invention include graphite fibers.

As the carbon fiber in the present invention, it is preferable to use a carbon fiber having a high tensile modulus so that a sufficient amount of material can be used for sports equipment such as a shaft for a golf club and a fishing rod with the use of a small amount of material. . The tensile modulus of such carbon fibers is preferably 200 GPa or more, and more preferably 210 to 800 GPa.

The higher the tensile strength of the carbon fiber, the higher the shear strength tends to be, but at this time, the tensile modulus tends to be low. Therefore, since the shear strength has a trade-off relationship with the tensile modulus, it is important to improve the shear strength of CFRP while keeping the tensile modulus of the carbon fiber high.

As the form of the carbon fibers, those in which the directions of the fibers are aligned in substantially the same direction, and woven fabrics can be used. The woven fabric may be any of plain weave and satin weave.

By increasing the adhesion between the carbon fiber and the matrix resin (hereinafter simply referred to as adhesion), CFRP
Has an increased in-plane shear strength. Methods for improving the adhesiveness include a method of mainly modifying the surface of the carbon fiber and a method of modifying the matrix resin to enhance the affinity and the adhesiveness with the carbon fiber.

In the present invention, the carbon fiber has a surface specific oxygen concentration O / C (hereinafter referred to as O / C) measured by X-ray photoelectron spectroscopy.
/ C) is preferably 0.02 or more, more preferably 0.04 or more, and even more preferably 0.06 or more. Here, the upper limit of O / C is preferably 0.3, and more preferably 0.25. When the O / C is less than 0.02, the affinity with a matrix resin described below is reduced, and
In FRP, improvement of in-plane shear strength may not be expected. When the O / C exceeds 0.3, the affinity between the carbon fiber and the matrix resin becomes strong, but the oxide layer having a strength characteristic significantly lower than that of the carbon fiber itself covers the surface of the carbon fiber. CFR obtained
The strength characteristics of P may be impaired.

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.
The above is good, and preferably 0.5% or more. Here, the upper limit of COOH / C is preferably 3.0%, and more preferably 2.0%. If COOH / C is less than 0.2%, the affinity with the matrix resin described below decreases, and in CFRP, improvement in in-plane shear strength may not be expected. When COOH / C exceeds 3.0%, the affinity between the carbon fiber and the matrix resin becomes strong,
Since the oxide layer having a strength characteristic significantly lower than that of the carbon fiber itself covers the surface of the carbon fiber, the strength characteristics of the obtained CFRP tend to be impaired, and the curing speed of the matrix resin is reduced. May be delayed.

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

The polymer component comprises 95 mol% or more, preferably 98 mol% or more of acrylonitrile (AN);
A material which promotes flame resistance of 5 mol% or less, preferably 2 mol% or less, and which is copolymerized with acrylonitrile (AN) and which has a flame retardation promoting component, can be suitably used. As the flame-resistance-promoting component, a copolymer comprising a vinyl group-containing compound (hereinafter, referred to as a vinyl monomer) can be suitably used. Specific examples of vinyl monomers include acrylic acid,
Examples include methacrylic acid and itaconic acid. Further, a copolymer composed of an ammonium salt of acrylic acid, methacrylic acid, or itaconic acid, which is partially or wholly neutralized with ammonia, can be more suitably used as a component for promoting flame resistance. As the polymerization method, a conventionally known solution polymerization method, suspension polymerization method, emulsion polymerization method and the like can be applied.

The spinning dope comprising the polymer component is spun by a wet spinning method, a dry spinning method, a dry spinning method, or a melt spinning method. Of these, the wet spinning method or the dry spinning method is preferably employed. As the solvent used for the spinning dope, conventionally known organic and inorganic solvents can be used. In particular,
It is preferable to use an organic solvent, and specific examples include dimethylsulfoxide, dimethylformamide, and dimethylacetamide. When a concentrated aqueous solution of an inorganic salt such as an aqueous solution of nitric acid, aqueous solution of soda, or aqueous solution of zinc chloride is used as a solvent, a carbon fiber having a desired surface roughness may not be obtained. The coagulated yarn after spinning is subjected to a spinning process such as washing with water, stretching, drying and application of an oil agent to produce an acrylic precursor.

Further, by making the acrylic precursor flame-resistant and carbonized, carbon fibers having desired performance can be obtained. From the viewpoint of productivity, the precursor used for flame resistance is preferably one having a single-fiber fineness of 3 to 11 μm, preferably 3 to 9 μm, more preferably 3 to 7 μm.
m is preferred. Further, the number of single fibers per thread is preferably 10,000 to 60,000, and
48,000 are more preferable.

Hereinafter, the oxidation-resistant conditions will be specifically described.
Note that the flameproofing condition is not limited to this.

The draw ratio for flame resistance is 0.85-1.
It is preferable to set the flame resistance to 0. The draw ratio is set to 0.87 to 0.5 to suppress burn unevenness as a yarn bundle.
94 is more preferred. If the draw ratio is less than 0.85, the processability decreases, and if it exceeds 1.0, the diffusion of oxygen into the yarn bundle is hindered, and the burn unevenness at the center of the yarn bundle tends to be remarkable.

The oxidization temperature is preferably 200 to 300 ° C.
In each degree of oxidization, oxidization at a temperature 10 to 20 ° C. lower than the temperature at which yarn breakage occurs due to heat storage of reaction heat is preferable from the viewpoint of cost reduction and enhancement of carbon fiber performance. 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. Such flame shrinkage retention is
The flame resistance is preferably 70 to 90%, more preferably 74 to 86%, and more preferably 76 to 84%.

The oxidizing time is preferably from 10 to 100 minutes, and more preferably from 30 to 60 minutes, from the viewpoint of improving the productivity and the performance of the carbon fiber. This oxidization time refers to the entire time that the precursor stays in the oxidization furnace. If this time is too short, burn unevenness becomes remarkable, and the performance of the obtained carbon fiber may decrease.

After the precursor is made flame-resistant in this way, it is carbonized in the subsequent carbonization step to form carbon fibers.

In the carbonization step, 300-
Preliminary carbonization at 800 ° C.
It is necessary to carbonize at １1600 ° C. The latter carbonization temperature is preferably 1100 ° C. or higher, and more preferably 1200 ° C. or higher. That is, when the temperature is lower than 1100 ° C., the moisture content contained in the obtained carbon fiber may increase. The upper limit of the carbonization temperature is preferably 1600 ° C., more preferably 1500 ° C. If it exceeds 1600 ° C., crystal growth in the fiber becomes remarkable, and the compressive strength and the adhesiveness tend to decrease.

The stretching ratio in the preliminary carbonization step is as follows:
1.0-1.5 is good, preferably 1.02-1.3,
More preferably, it is 1.04 to 1.15. The higher the draw ratio is, the more advantageous in terms of the tensile modulus, but the followings are possible.
If it exceeds 5, the processability may be significantly reduced.

The heating rate and the treatment time in the carbonization step can be appropriately selected in consideration of the desired performance of the carbon fiber and the required cost. In particular, it is preferable that the usually adopted heating rates of 300 to 500 ° C./min and 1000 to 1200 ° C./min are respectively 1000 ° C./min or less, more preferably 500 ° C./min. Further, it is preferable from the viewpoint of cost reduction that the carbonization treatment time be as short as possible within a range in which the degree of carbonization does not matter.

Further, the carbon fiber in the present invention is
00 to 3300 ° C, preferably 2000 to 3000 ° C,
More preferably, by graphitizing in an inert atmosphere at 2000 to 2800 ° C., compared to conventional graphite fibers,
It is possible to obtain a graphite fiber having remarkably excellent strength characteristics.

As described above, in the obtained fiber-reinforced composite material, in order to increase the 0-degree compression strength and the 90-degree tensile strength, it is preferable to increase the adhesiveness. In order to enhance the adhesiveness, it is preferable that the carbon fiber has a small crystal and a large number of curing points. For such carbon fibers, the crystal size L _C of the carbon network plane determined by wide-angle X-rays needs to be 5 to 40 Å, and preferably the crystal size L
_C is preferably 10 to 30 angstroms, and more preferably 15 to 25 angstroms.

The carbon fibers having a specific range of O / C and COOH / C can be easily obtained by subjecting them to electrolytic oxidation treatment after carbonization or oxidation treatment in a gas phase or a liquid phase.

The electrolytic solution for the electrolytic oxidation treatment may be either an acidic or alkaline aqueous solution. As the electrolyte of the acidic aqueous solution, sulfuric acid, nitric acid, hydrochloric acid, or the like can be used. As the electrolyte of the alkaline aqueous solution, a compound containing an ammonium ion is preferable, and specifically, ammonium hydrogen carbonate, ammonium carbonate, a tetraalkylammonium hydroxide salt, or a mixture thereof can be used. Among them, ammonium hydrogen carbonate and ammonium carbonate are preferred.

The amount of electricity required for the electrolytic treatment is preferably optimized in accordance with the degree of carbonization of the carbon fiber, but from the viewpoint of suppressing a decrease in the tensile strength of the carbon fiber substrate and lowering the crystallinity of the surface layer of the carbon fiber. Therefore, it is preferable that the electrolytic treatment is performed in a plurality of times with a small amount of electricity. Specifically, the amount of electricity per electrolytic cell is 1 coulomb / g · tank (1 g of carbon fiber, the number of coulombs per cell) to 40 coulombs / g ·
A bath is preferred.

As an energizing method, either direct energizing in which the carbon fiber is brought into direct contact with the electrode roller and energizing, or indirect energizing in which an electrolytic solution is applied between the carbon fiber and the electrode, can be employed. In order to obtain a high tensile strength in the carbon fiber substrate, it is preferable to use indirect energization in which the fiber bundle is fluffed during the electrolytic treatment and the electric spark is suppressed.

After the electrolytic treatment, it is preferable to wash and dry. In this case, in order to improve the affinity and adhesion to the resin composition described below, it is desirable to dry the carbon fiber 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. The drying temperature is 180
The drying is preferably carried out at a temperature of 180 to 210 ° C.

The matrix resin in the prepreg and CFRP of the present invention comprises the following components (A), (B),
It comprises an epoxy resin composition containing (C) and (D).

(A) Epoxy resin (B) Curing agent (C) Thermoplastic resin (D) Epoxy resin (A) or curing agent (B) in the molecule
Compound having one functional group and one or more amide bond capable of reacting with epoxy resin The epoxy resin which is a component (A) of the epoxy resin composition means a compound having two or more epoxy groups in a molecule. I do.

Specifically, glycidyl ether obtained from a polyol, glycidylamine obtained from an amine having a plurality of active hydrogens, glycidyl ester obtained from a polycarboxylic acid, and a compound having a plurality of double bonds in a molecule are oxidized. For example, a polyepoxide obtained by the above method is used.

The following are specific examples of the glycidyl ether.

First, a bisphenol A type epoxy resin obtained from bisphenol A, a bisphenol F type epoxy resin obtained from bisphenol F, a bisphenol S type epoxy resin obtained from bisphenol S, and a tetrabromobisphenol A type obtained from tetrabromobisphenol A A bisphenol-type epoxy resin such as an epoxy resin is exemplified. A commercially available bisphenol A type epoxy resin is “Epicoat” 825
(Epoxy equivalent 172 to 178), "Epicoat" 82
8 (epoxy equivalents 184-194), "Epicoat" 8
34 (epoxy equivalent 230-270), "Epicoat"
1001 (epoxy equivalent 450-500), "Epicoat" 1002 (epoxy equivalent 600-700), "Epicoat" 1003 (epoxy equivalent 670-770),
"Epicoat" 1004 (epoxy equivalent 875-97
5), “Epicoat” 1007 (epoxy equivalent 1750)
２2200), “Epicoat” 1009 (epoxy equivalent 2400 to 3300), “Epicoat” 1010 (epoxy equivalent 3000 to 5000) (registered trademark, manufactured by Yuka Shell Epoxy Co., Ltd.), “Epototo” YD-128
(Epoxy equivalent 184-194) "Epototo" YD-
011 (epoxy equivalent 450-500), "Epototo" YD-014 (epoxy equivalent 900-1000),
"Epototo" YD-017 (epoxy equivalent 1750-
2100), “Epototo” YD-019 (epoxy equivalent: 2400-3000), “Epotote” YD-022
(Epoxy equivalent 4000 to 6000), (the above-mentioned registered trademark made by Toto Kasei Co., Ltd.), "Epiclon" 840 (Epoxy equivalent 180 to 190), "Epiclon" 850 (Epoxy equivalent 184-194), "Epiclon" 1050
(Epoxy equivalent 450-500), "Epiclon" 30
50 (epoxy equivalent 740-860), "Epiclon"
HM-101 (Epoxy equivalent 3200-3900) (registered trademark, manufactured by Dainippon Ink and Chemicals, Inc.), "Sumi Epoxy" ELA-128 (Epoxy equivalent 184-19)
4, registered trademark, manufactured by Sumitomo Chemical Co., Ltd.), DER331
(Epoxy equivalents 182 to 192, manufactured by Dow Chemical Co., Ltd.) and the like can be used. Commercially available bisphenol F type epoxy resins include “Epicoat” 806 (epoxy equivalent 160 to 170), “Epicoat” 807 (epoxy equivalent 160 to 175), and “Epicoat” E400.
2P (epoxy equivalent 610), "Epicoat" E400
3P (epoxy equivalent 800), "Epicoat" E400
4P (epoxy equivalent 930), "Epicoat" E400
7P (epoxy equivalent 2060), "Epicoat" E40
09P (Epoxy equivalent 3030), "Epicoat" E4
010P (epoxy equivalent 4400) (registered trademark, manufactured by Yuka Shell Epoxy Co., Ltd.), "Epiclon" 830
(Epoxy equivalent: 165 to 180, registered trademark, manufactured by Dainippon Ink and Chemicals, Inc.), "Epototo" YDF-200
1 (Epoxy equivalent 450-500), "Epototo" Y
DF-2004 (epoxy equivalent: 900 to 1000) (registered trademark, manufactured by Toto Kasei Co., Ltd.) or the like can be used. As a commercially available bisphenol S-type epoxy resin, "Denacol" EX-251 (registered trademark, manufactured by Nagase Kasei Kogyo Co., Ltd., epoxy equivalent: 189) can be used. A commercially available tetrabromobisphenol A type epoxy resin is “Epicoat” 5050
(Registered trademark, manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent: 380-410), "Epiclon" 152 (registered trademark, manufactured by Dainippon Ink and Chemicals, Inc., epoxy equivalent: 34)
0-380), "Sumi-Epoxy" ESB-400T
(Registered trademark, manufactured by Sumitomo Chemical Co., Ltd., epoxy equivalent 38
0-420), "Epototo" YBD-360 (registered trademark, manufactured by Toto Kasei Co., Ltd., epoxy equivalent 350-370)
Etc. can be used.

Further, phenol, alkylphenol,
A novolak-type epoxy resin which is a glycidyl ester of novolak obtained from a phenol derivative such as a halogenated phenol is exemplified. Commercial products of the novolak type epoxy resin include “Epicoat” 152 (epoxy equivalent 172 to 179), “Epicoat” 154 (epoxy equivalent 176 to 181) (registered trademark, manufactured by Yuka Shell Epoxy Co., Ltd.), DER438 ( Epoxy equivalent 176
181, registered trademark, manufactured by Dow Chemical Company), “Araldite” EPN1138 (epoxy equivalents 176 to 181,
Registered trademark, manufactured by Ciba Co., Ltd.), "Araldite" EPN113
9 (epoxy equivalent: 172 to 179, registered trademark, manufactured by Ciba), "Epototo" YCPN-702 (epoxy equivalent: 200 to 230, registered trademark, manufactured by Toto Kasei Co., Ltd.), BR
EN-105 (epoxy equivalents 262 to 278, registered trademark, manufactured by Nippon Kayaku Co., Ltd.) or the like can be used.

In addition, resorcin diglycidyl ether “Denacol” EX-201 (registered trademark, manufactured by Nagase Kasei Kogyo Co., Ltd., epoxy equivalent 118), hydroquinone diglycidyl ether “Denacol” EX
-203 (registered trademark, manufactured by Nagase Kasei Kogyo Co., Ltd., epoxy equivalent 112), 4,4'-dihydroxy-3,3 ',
5,5'-tetramethylbiphenyldiglycidyl ether "Epicoat" YX4000 (registered trademark, manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent 180 to 19)
2) “Epiclone” HP-4032H, a diglycidyl ether of 1,6-dihydroxynaphthalene (registered trademark, manufactured by Dainippon Ink and Chemicals, Inc., epoxy equivalent 2)
50) "Epon" HP, a diglycidyl ether of 9,9-bis (4-hydroxyphenyl) fluorene
T Resin 1079 (registered trademark, manufactured by Shell Co., epoxy equivalent 250-260), TACTI which is a triglycidyl ether of tris (p-hydroxyphenyl) methane
X742 (Dow Chemical Co., epoxy equivalent 150-
157), “Epicoat” 1 which is a tetraglycidyl ether of tetrakis (p-hydroxyphenyl) ethane
031S (registered trademark, manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent: 196), "Denacol" EX-314, a triglycidyl ether of glycerin (registered trademark, manufactured by Nagase Kasei Kogyo Co., Ltd., epoxy equivalent: 145), penta "Denacol" EX-411 (registered trademark, manufactured by Nagase Kasei Kogyo Co., Ltd., epoxy equivalent: 231) which is a tetraglycidyl ether of erythritol can be used.

Specific examples of glycidylamine include “Sumi-Epoxy” ELM434 (registered trademark, manufactured by Sumitomo Chemical Co., Ltd., epoxy equivalent: 110-1), which is diglycidylaniline and tetraglycidyldiaminodiphenylmethane.
30), tetraglycidyl m-xylylenediamine "TETRAD-X" (registered trademark, manufactured by Mitsubishi Gas Chemical Company, Inc., epoxy equivalent: 90 to 105) and the like.

Further, as an epoxy resin having both structures of glycidyl ether and glycidylamine, “Sumi-epoxy” ELM120 (epoxy equivalent 118, registered trademark, manufactured by Sumitomo Chemical Co., Ltd.) which is a triglycidyl-m-aminophenol , And "Araldite" MY0510 (registered trademark, manufactured by Ciba Geigy, epoxy equivalent 94 to 10), which is a triglycidyl-p-aminophenol
7) and the like.

Specific examples of glycidyl esters include diglycidyl phthalate, diglycidyl terephthalate, diglycidyl dimer, and the like.

Further, other epoxy resins having a glycidyl group include triglycidyl isocyanurate.

The polyepoxide obtained by oxidizing a compound having a plurality of double bonds in the molecule includes an epoxy resin having an epoxycyclohexane ring.
A specific example is ERL-42 manufactured by Union Carbide.
06 (epoxy equivalent 70-74), ERL-4221
(Epoxy equivalents 131 to 143), ERL-4234
(Epoxy equivalents 133 to 154). Further, epoxidized soybean oil and the like are also included.

Component (B) of the epoxy resin composition
Examples of the curing agent include 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylsulfone,
Aromatic amine having active hydrogen such as 3'-diaminodiphenyl sulfone, m-phenylenediamine, m-xylylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine, bis (aminomethyl) norbornane, bis (4-aminocyclohexyl) )
Methane, an aliphatic amine having an active hydrogen such as a dimer acid ester of polyethyleneimine, an epoxy compound, acrylonitrile,
Modified amine obtained by reacting a compound such as phenol with formaldehyde and thiourea, dimethylaniline,
Tertiary amines without active hydrogen such as dimethylbenzylamine, 2,4,6-tris (dimethylaminomethyl) phenol and 1-substituted imidazole, dicyandiamide, tetramethylguanidine, hexahydrophthalic anhydride, tetrahydrophthalic acid Anhydrides, carboxylic anhydrides such as methylhexahydrophthalic anhydride and methylnadic anhydride, polycarboxylic acid hydrazides such as adipic hydrazide and naphthalenedicarboxylic acid hydrazide, polyphenol compounds such as novolak resins, and thioglycolic acid And polymer polyols such as esters of polyols, Lewis acid complexes such as boron trifluoride ethylamine complex, and aromatic sulfonium salts.

The compounding amount of the curing agent (B) is preferably 2 to 10 parts by weight, more preferably 3 to 6 parts by weight, per 100 parts by weight of the epoxy resin (A). If the amount is less than 2 parts by weight, the curing is insufficient and the heat resistance tends to be low. If the amount is more than 10 parts by weight, the reactivity becomes high and the storage stability of the prepreg may deteriorate.

These curing agents can be combined with an appropriate curing aid to enhance the curing activity. Preferred examples include dicyandiamide with 3-phenyl-
1,1-dimethylurea, 3- (3,4-dichlorophenyl) -1,1-dimethylurea (DCMU), 3- (3-
Examples of combining urea derivatives such as chloro-4-methylphenyl) -1,1-dimethylurea, 2,4-bis (3,3-dimethylureido) toluene as curing aids,
Examples include combining a carboxylic acid anhydride or a novolak resin with a tertiary amine as a curing aid.

Component (C) of the epoxy resin composition
By blending a thermoplastic resin, the effects of controlling the viscosity of the resin, controlling the handling of the prepreg, and improving the adhesiveness are 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 of improving the adhesiveness which is the object of the present invention.

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 resin and polyvinyl butyral resin, polyvinyl alcohol, phenoxy resin, and thermoplastic resins having an amide bond include polyamide, polyimide and sulfonyl groups. Examples of the thermoplastic resin include polysulfone. 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 on the nitrogen atom of the amide group.

Of these, polyvinyl acetal resins such as polyvinyl formal resin and polyvinyl butyral resin are preferable, and polyvinyl formal resin is particularly preferable. Further, it is preferable that the average degree of polymerization of the polyvinyl formal resin is 2,000 or less, since the resin easily melts when mixed with the epoxy resin by heating. The average degree of polymerization of the polyvinyl formal resin is more preferably 1,000 or less, and still more preferably 600 or less.

Commercially available thermoplastic resins having a hydrogen-bonding functional group which are soluble in an epoxy resin include, for example, "denkabutyral" and "denkaformal" (registered trademark, manufactured by Denki Kagaku Kogyo Co., Ltd.) as polyvinyl acetal resins. )
"Vinilec" (registered trademark, manufactured by Chisso Corporation),
"UCAR" PKHP (registered trademark, manufactured by Union Carbide) as a phenoxy resin, "Macromelt" (registered trademark, Henkel Hakusui Co., Ltd.) as a polyamide resin
"Amilan" CM4000 (registered trademark, manufactured by Toray Industries, Inc.), "Ultem" (registered trademark, manufactured by General Electric Co., Ltd.) as a polyimide, "Matri"
mid "5218 (registered trademark, manufactured by Ciba), and" Victrex "(registered trademark, manufactured by Mitsui Chemicals, Inc.) and" UDEL "(registered trademark, manufactured by Union Carbide) as polysulfone.

When the thermoplastic resin (C) is contained in an amount of 1 to 20 parts by weight with respect to 100 parts by weight of the epoxy resin (A), the epoxy resin composition imparts an appropriate viscoelasticity and good physical properties of the composite material. It is preferable in that it can be obtained.

However, when the prepreg is cured to form a carbon fiber reinforced composite material, the thermoplastic resin in the matrix resin may cause layer separation. In this case, if the average particle size of the thermoplastic resin in the carbon fiber reinforced composite material is large, the effect of improving the 90-degree tensile strength is reduced, so that it is necessary that the thermoplastic resin is dispersed at an average particle size of 10 μm or less. More preferably, the particles are dispersed with a diameter of 5 μm or less. From such a point, when a thermoplastic resin that causes layer separation is contained, the thermoplastic resin (C) is replaced with the epoxy resin (A) 10.
It is preferable that it is contained in an amount of 1 to 15 parts by weight with respect to 0 parts by weight in that good composite material properties are obtained.

Here, for example, Os
It can be performed by an electron microscope using an O ₄ -stained ultrathin section method. In addition, a material that largely separates layers can be observed with an optical microscope. For example, an average particle diameter of 5 μm means that in the case of spherical uniform dispersion, the number average of the diameters of all particles in a 300 μm square cross section is 5 μm. In the case of an elliptical shape or an irregular shape, the temporary diameter of one particle is represented by (the longest diameter + the shortest diameter) / 2, and the cross section of about 300 μm square is represented by the number average of the diameters of all particles, This is 5 μm
That is. Further, the dispersed state may be particles in which the epoxy resin is contained in the thermoplastic resin particles.

Constituent (D) of the epoxy resin composition
Epoxy resin (A) or curing agent (B) in the molecule
A compound having one functional group and one or more amide bonds capable of reacting with a compound is compounded as a highly polar compound for improving adhesion.

The amide bond referred to herein means a partial structure comprising a group selected from a carbonyl group, a thiocarbonyl group, a sulfonyl group, and a phosphoryl group, and a nitrogen atom bonded to the carbon by a single bond. A typical compound having an amide bond is a carboxylic acid amide, but may have an amide bond in a part of the ring, or may have a more complex structure such as imide, urethane, urea, or the like.
It may have a structure such as biuret, hydantoin, carboxylic acid hydrazide, hydroxamic acid, semicarbazide, semicarbazone and the like.

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

Further, since the carbonyl group of the amide bond is a strong permanent dipole, an organic dipole is formed on a reinforcing fiber having a high polarizability such as carbon fiber, and the adhesive property is improved by the electric attraction between the dipole and the dipole. Enhance.

If the compound having an amide bond does not have a functional group capable of reacting with the epoxy resin (A) or the curing agent (B), adhesiveness may not be sufficiently exhibited due to phase separation, or the compound may act as a plasticizer and be heat resistant. If the compound having an amide bond has a functional group that can react with the epoxy resin (A) or the curing agent (B), the epoxy resin may be cured with the curing of the resin composition. Since it becomes a part of the network of the cured product, there is no possibility of causing the above-mentioned adverse effects.

An epoxy resin composition containing a compound having two or more functional groups capable of reacting with the epoxy resin (A) or the curing agent (B) and one or more amide bonds is prepared by CFRP
It is known to be used, but in these known techniques,
No remarkable improvement in adhesion has been confirmed. However, the epoxy resin composition found by the present inventors in which a compound having one functional group capable of reacting with the epoxy resin (A) or the curing agent (B) and having one or more amide bonds in the molecule is blended. Has a remarkable effect.

The reason for this is that a compound having two or more functional groups capable of reacting with the epoxy resin (A) or the curing agent (B) is chemically bonded to the epoxy resin network at two or more places. The compound having only one functional group capable of reacting with the epoxy resin (A) or the curing agent (B) is chemically bonded to the epoxy resin network at only one place, while the oxygen atom cannot sufficiently access the carbon fiber surface. Therefore, the present inventors presume that the degree of freedom of movement of the partial structure derived from the compound is large, and the oxygen atom of the carbonyl group easily contacts the carbon fiber surface.

Further, the addition of the component (D) not only increases the adhesiveness but also has the effect of increasing the flexural modulus of the cured product of the epoxy resin composition. This is considered 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.

Examples of the functional group capable of reacting with the epoxy resin (A) include a carboxyl group, a phenolic hydroxyl group, an amino group, a secondary amine structure, and a mercapto group.
In addition, 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,
Examples thereof include 3-aminophthalimide and 4-aminophthalimide.

Specific examples of the compound 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 and N- (2-mercaptoethyl) acetamide.

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

In the compound having one double bond conjugated to a carbonyl group and having an amide bond, the carbonyl group conjugated to the double bond may be the same as or different from the carbonyl group of the amide bond. . Compounds 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 derivatives thereof having a substituent on the nitrogen atom. Specific examples include acrylamide, methacrylamide,
N, N-dimethylacrylamide, N, N-diethylacrylamide, N-tert-butylacrylamide,
N-isopropylacrylamide, N-butylacrylamide, N-hydroxymethylacrylamide, N-methoxymethylacrylamide, N-ethoxymethylacrylamide, Nn-propoxymethylacrylamide, Nn-butoxymethylacrylamide, N-isobutoxymethylacrylamide , N-benzyloxymethylacrylamide, diacetone acrylamide, 1-acryloylmorpholine, 1-acryloylpiperidine and the like. In addition, imides of unsaturated dicarboxylic acids such as maleimide, N-ethylmaleimide, and N-phenylmaleimide are also applicable. 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.

Compounds having one functional group and one or more amide bonds capable of reacting with the epoxy resin (A) or the curing agent (B) in the molecule as the constituent element (D) may be used alone or in combination. May be.

The amount of the component (D) (when a plurality of components are used, the total thereof) is preferably 0.5 to 15 parts by weight per 100 parts by weight of the component (A). When the amount is less than 0.5 part, the effect of improving the adhesiveness is not sufficiently exhibited, and when the amount is more than 15 parts by weight, adverse effects such as a decrease in heat resistance may be caused.

The component (D) may be a liquid or a solid at room temperature. When a solid component is used as the component (D), after blending in the epoxy resin composition,
You may melt | dissolve by means, such as heating stirring, and may mix | blend without melt | dissolving. When the solid component (D) is blended without dissolving, it is preferable to use the solid component (D) by pulverizing it to a particle size of 10 μm or less.

In the present invention, in addition to the components (A), (B), (C), and (D), other components such as organic or inorganic particles may be added to the epoxy resin composition. Can be blended.

Rubber particles and thermoplastic resin particles are used as the organic particles to be added to the epoxy resin composition.
These particles have the effect of improving the toughness of the resin and the impact resistance of CFRP.

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

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

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, acrylate / methacrylic acid "STAPHYLOID" AC-3355 comprising an ester copolymer, TR-2122 (registered trademark, manufactured by Takeda Pharmaceutical Co., Ltd.), "PARALOID" EXL- comprising a butyl acrylate / methyl methacrylate copolymer
2611, EXL-3387 (registered trademark, Rohm &
Haas).

As the thermoplastic resin particles, polyamide or polyimide particles are preferably used. As commercially available polyamide particles, SP-500, A manufactured by Toray Industries, Inc.
"Orgasol" (registered trademark) manufactured by TOCHEM and the like.

As the inorganic particles, silica, alumina, smectite, synthetic mica and the like can be blended.
These inorganic particles are blended mainly for rheological control, that is, for thickening and imparting thixotropic properties.

In order to increase the in-plane shear strength of CFRP, it is preferred that the resin composition has a high flexural modulus and a high tensile elongation of the cured product of the resin composition. The flexural modulus of the cured product is preferably not less than 3.1 GPa, preferably not less than 3.3 GPa, and more preferably not less than 3.3 GPa. The cured product has a tensile elongation of preferably 8% or more, and more preferably 10% or more. In order to obtain such tensile elongation, it is preferable that 70 to 100% by weight of the total epoxy resin (A) is a bifunctional epoxy resin.

Hereinafter, a method for producing the prepreg of the present invention and a method for laminating the same and heating and curing to obtain CFRP will be described.

The prepreg is produced by a wet method in which a matrix resin is dissolved in a solvent such as methyl ethyl ketone or methanol to reduce the viscosity and impregnated, or a hot melt method in which the viscosity is reduced by heating and impregnated. .

The wet method is a method in which carbon fibers are immersed in a liquid comprising an epoxy resin composition, pulled up, and the solvent is evaporated using an oven or the like to obtain a prepreg.

The hot melt method is a method of directly impregnating carbon fibers with an epoxy resin composition whose viscosity has been reduced by heating, or a method in which a film in which the epoxy resin composition is once coated on release paper is first prepared, This is a method of producing a prepreg impregnated with a resin by laminating the film from both sides or one side of the fiber and applying heat and pressure. The hot melt method is preferable because there is no solvent remaining in the prepreg.

The molding of CFRP using the prepreg can be carried out by laminating the prepreg and then heating and curing the resin while applying pressure to the laminate.

Examples of the method for applying heat and pressure include a press molding method, an autoclave molding method, a bagging molding method, a wrapping tape method, and an internal pressure molding method. Particularly, for sports goods, the wrapping tape method and the internal pressure molding method are used. It is preferably adopted.

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 material, and is suitable for producing a rod-like body such as a golf club shaft and a fishing rod. Specifically, a prepreg is wound around a mandrel, a wrapping tape made of a thermoplastic resin film is wound around the outside of the prepreg for fixing the prepreg and applying pressure, and after heating and curing the resin in an oven, the core metal is removed. Pull out to obtain a cylindrical molded body.

In the internal pressure forming method, a preform in which a prepreg is wound around an internal pressure applying body such as a thermoplastic resin tube is set in a mold, and then a high-pressure gas is introduced into the internal pressure applying body to reduce the pressure. This is a method in which the mold is heated and molded simultaneously with the application. It is suitably used when molding a complicated shape such as a golf club shaft, a bat, and a racket such as tennis and badminton.

[0117]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments. Preparation of prepreg, preparation of cylindrical CFRP, and measurement of various physical properties were performed by the following methods. 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 A. Measurement of flexural modulus The resin composition was heated to 80 ° C and poured into a mold.
The resin was cured by heating in a hot-air dryer at 5 ° C. for 2 hours to produce a cured resin plate having a thickness of 2 mm. Next, 10m wide from the cured resin plate
m, a test piece having a length of 60 mm was cut out and tested at a test speed of 2.5
Bending test at a distance of 32 mm and a fulcrum distance of 32 mm.
The flexural modulus was determined according to SK7203.

B. Measurement of tensile elongation JIS K7
In accordance with No. 113, a small No. 1 (1/2) type test piece was cut out and the tensile elongation was determined. (2) Measurement of Tensile Modulus of Carbon Fiber "Bakelite" (registered trademark) ERL-4221 manufactured by Union Carbide Co., Ltd.
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 modulus. (3) Preparation of prepreg The resin composition was applied on release paper using a reverse roll coater to prepare a resin film. Next, two resin films were overlaid on carbon fibers aligned in one direction in a sheet form from both sides of the carbon fibers, and heated and pressed to impregnate the resin composition, thereby obtaining a prepreg having a carbon fiber weight of 125 g / m ² . . (4) Measurement of in-plane shear strength A predetermined number of unidirectional prepregs were laminated so that the direction of carbon fibers was ± 45 °, and the temperature was 135 ° C in an autoclave.
A sample prepared by curing by heating and pressing at a pressure of 290 Pa for 2 hours was measured according to JIS K7079. (5) by operating the fabrication of cylindrical CFRP following (a) ~ (e), it has a laminated structure of [0 ₃ / ± 45 _3] with respect to the cylinder axis, an inner diameter of 6.3mm
And two types of 10 mm cylindrical CFRP. As the mandrel, a stainless steel round bar having a diameter of 6.3 mm and 10 mm (both having a length of 1000 mm) was used. (A) A mandrel having a diameter of 6.3 mm is 800 mm long × 68 mm wide and 10 mm in diameter so that the direction of the fiber is 45 ° with respect to the axial direction of the mandrel.
Was cut into two rectangular pieces of 800 mm length × 103 mm width. These two sheets are crossed so that the fiber directions cross each other, and are 10 mm in the lateral direction of the mandrel having a diameter of 6.3 mm, and 16 mm in the mandrel having the diameter of 10 mm.
(Corresponding to half the circumference of the mandrel) (B) The bonded prepreg was wound around a mandrel subjected to a release treatment so that the longitudinal direction of the prepreg coincided with the axial direction of the mandrel. (Bias material) (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 in width was wound so that the longitudinal direction of the prepreg coincided with the axial direction of the mandrel. (Straight material) (d) A wrapping tape (heat-resistant film tape) was wrapped around and heated and molded at 130 ° C. for 2 hours in a curing furnace. (E) After molding, the mandrel was pulled out and the wrapping tape was removed to obtain a cylindrical CFRP. (6) Measurement of physical properties of cylindrical CFRP Measurement of bending strength Using a cylindrical CFRP with an inner diameter of 10 mm, "Certification standards 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. 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. 300m between supporting points
m, and the test speed was 5 mm / min.

B. Measurement of torsional strength A test piece having a length of 400 mm was cut out from a cylindrical CFRP having an inner diameter of 10 mm. )
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.

Torsional strength (N · m · deg) = breaking torque (N · m)
C. Torsion angle at break (deg) C. Measurement of crushing strength A test piece having a length of 15 mm was cut out from a cylindrical CFRP 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 crushing strength. The test speed was 5 mm / min.

D. Measurement of Charpy impact strength JIS K7 except that cylindrical CFRP was used for the test piece
The Charpy impact test was performed according to the method described in No. 077. A test piece having a length of 90 mm is cut out from a cylindrical CFRP having an inner diameter of 6.3 mm, and an impact is applied from a direction perpendicular to the cylinder axis direction at a distance between fulcrums of 40 mm, a hammer swing angle of 135 degrees, and a weighing of 300 kg · cm, and the maximum impact load is measured The load value was defined as impact strength. (7) 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, from the carbon fiber bundle to be measured,
After removing the sizing agent and the like with a solvent, the sample was cut into an appropriate length, spread on a stainless steel sample support table, and measured under the following conditions.

[0122] - 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
Obtained by drawing a linear base line in the range of 2 to 296 eV, the O _1s peak area [C _1s ] is 528 to 54
It was determined by drawing a straight base line in the range of 0 eV.

The surface specific oxygen concentration O / C is calculated as follows._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) Here, as a measuring device, a product of Shimadzu Corporation is used.
Using ESCA-750, the sensitivity correction value unique to the device was set to 2.85. B. Surface carboxyl group concentration COOH / C Surface carboxyl group concentration COOH / C was determined by chemically modified 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 into an appropriate length, spread on a platinum sample support, and then arranged at 0.02 mol / L.
Was exposed to air containing 60% of dicyclohexylcarbodiimide gas and 0.04 mol / L of pyridine gas at 60 ° C. for 8 hours for chemical modification treatment, and then measured under the following conditions.

Photoelectron escape angle: 35 degrees X-ray source: AlKα1, 2 Vacuum in sample chamber: 1 × 10 ⁻⁸ Torr Next, the main component of C _1S was used to correct peaks due to charging during measurement. B. Peak binding energy value E. FIG. 284.6 eV
I adjusted to.

Next, the C _1s peak area [C _1s ] is 28
It is obtained by drawing a linear base line in the range of 2 to 296 eV, and the F _1s peak area [F _1s ] is 682 to 69
It was determined by drawing a straight base line in the range of 5 eV.

[0129] Further, as a comparative sample, a chemical modification treatment polyacrylic acid C _1s peak splitting from the reaction rate r
And the residual ratio m of the dicyclohexylcarbodiimide derivative was determined from the O _1s peak splitting. Next, the surface carboxyl group concentration COOH / C was determined by the following equation.

COOH / C = [F _1s ] / [(3k [C _1s ]-(2 + 13m)
[F _1s ]) r] × 100 (%) Here, model SSX-100-206 manufactured by SSI, USA
Was used. The sensitivity correction value k of the F _1s peak area with respect to the C _1s peak area unique to this apparatus was 3.919. (8) Measurement of Average Particle Size of Thermoplastic Resin (C) The average particle size of the thermoplastic resin (C) was measured by electron microscopy using an OsO ₄ -stained ultrathin section method.

The sample was cut into ultrathin sections, and OsO ₄
After staining, the cells were observed with an electron microscope. When the particles were spherical, the number average of the diameters of all particles of 300 μm square was calculated to be the average particle diameter. If the particle is elliptical or irregular, the temporary diameter of one particle is (the longest diameter + the shortest diameter)
The average particle diameter was calculated by calculating the number average of the provisional diameters of all particles of 300 μm square.

Examples and comparative examples will be described below.
All parts described in Examples and Comparative Examples represent parts by weight. Example 1 The following materials were mixed in a kneader to obtain a resin composition. Component (A): Bisphenol A type epoxy resin 40 parts ("Epicoat" 828 (registered trademark), manufactured by Yuka Shell Epoxy Co., Ltd.) Bisphenol A type epoxy resin 50 parts ("Epicoat" 1001 (registered trademark), oil) Phenol novolak type epoxy resin 10 parts ("Epicoat" 154 (registered trademark), Yuka Shell Epoxy Co., Ltd.) Component (B); Dicyandiamide 5 parts (DICY7, Yuka Shell Epoxy) 3- (3,4-dichlorophenyl) -1,1-dimethylurea 3 parts (DCMU99, manufactured by Hodogaya Chemical Industry Co., Ltd.) Component (C); polyvinyl formal 5 parts (" Vinylek "K (registered trademark), manufactured by Chisso Corporation, average degree of polymerization 500) Component (D); N-isopropyl 3 parts of acrylamide (produced by Kojin Co., Ltd.) Using this resin composition and carbon fiber having a tensile modulus of elasticity of 294 GPa, a matrix resin content of 24% by weight was used to prepare a cured resin and a prepreg according to the method described above. Produced. The in-plane shear strength of CFRP obtained from the prepreg was 117 MPa, which satisfied the expression (1).

The average particle size of polyvinyl formal in CFRP was 0.5 μm.

Further, the crushing strength and impact strength of the cylindrical CFRP obtained by using this prepreg as the straight material and the bias material were good. Example 2 The following materials were mixed in a kneader to obtain a resin composition. Component (A): Bisphenol A type epoxy resin 40 parts ("Epicoat" 828 (registered trademark), manufactured by Yuka Shell Epoxy Co., Ltd.) Bisphenol A type epoxy resin 50 parts ("Epicoat" 1001 (registered trademark), oil) Shell Epoxy Co., Ltd.) Phenol novolak type epoxy resin 10 parts (“Epicoat” 154 (registered trademark), Yuka Shell Epoxy Co., Ltd.) Component (B); Dicyandiamide 5 parts (DICY7, Yuka Shell Epoxy) 3- (3,4-dichlorophenyl) -1,1-dimethylurea 3 parts (DCMU99, manufactured by Hodogaya Chemical Industry Co., Ltd.) Component (C); polyvinyl formal 15 parts (“ Vinylek “K (registered trademark), manufactured by Chisso Corporation) Component (D); N-isopropylacrylamide 3 Part (manufactured by Kojin Co., Ltd.) Using this resin composition and carbon fibers having a tensile modulus of elasticity of 294 GPa, a resin cured product and a prepreg were prepared according to the method described above with a matrix resin content of 24% by weight. . The in-plane shear strength of CFRP obtained from the prepreg was 115 MPa, which satisfied the expression (1).

The average particle size of polyvinyl formal in CFRP was 5 μm.

Further, the crushing strength and impact strength of the cylindrical CFRP obtained by using this prepreg as a straight material and a bias material were good. Comparative Example 1 A resin composition was obtained by mixing the following raw materials with a kneader. Component (A): Bisphenol A type epoxy resin 40 parts ("Epicoat" 828 (registered trademark), manufactured by Yuka Shell Epoxy Co., Ltd.) Bisphenol A type epoxy resin 50 parts ("Epicoat" 1001 (registered trademark), oil) Phenol novolak type epoxy resin 10 parts ("Epicoat" 154 (registered trademark), Yuka Shell Epoxy Co., Ltd.) Component (B); Dicyandiamide 5 parts (DICY7, Yuka Shell Epoxy) 3- (3,4-dichlorophenyl) -1,1-dimethylurea 3 parts (DCMU99, manufactured by Hodogaya Chemical Industry Co., Ltd.) Component (C); polyvinyl formal 20 parts (“ Vinylek "K (registered trademark), manufactured by Chisso Corporation, average degree of polymerization 500) Component (D); N-Isopropyl Acrylamide 3 parts (produced by Kojin Co., Ltd.) Using this resin composition and carbon fiber having a tensile modulus of elasticity of 294 GPa, according to the above-mentioned method, and setting the matrix resin content to 24% by weight, a resin cured product and a prepreg are prepared. Produced. The in-plane shear strength of CFRP obtained from the prepreg was 100 MPa, which satisfied the expression (1).

The average particle size of polyvinyl formal in CFRP was 20 μm.

Further, the crushing strength and impact strength of the cylindrical CFRP obtained by using this prepreg as a straight material and a bias material were poor. Example 3 The following raw materials were mixed in a kneader to obtain a resin composition. Component (A): Bisphenol A type epoxy resin 40 parts ("Epicoat" 828 (registered trademark), manufactured by Yuka Shell Epoxy Co., Ltd.) Bisphenol A type epoxy resin 50 parts ("Epicoat" 1001 (registered trademark), oil) Phenol novolak type epoxy resin 10 parts ("Epicoat" 154 (registered trademark), Yuka Shell Epoxy Co., Ltd.) Component (B); Dicyandiamide 5 parts (DICY7, Yuka Shell Epoxy) 3- (3,4-dichlorophenyl) -1,1-dimethylurea 3 parts (DCMU99, manufactured by Hodogaya Chemical Industry Co., Ltd.) Component (C); Polyvinylformal 7 parts (" Vinylek "K (registered trademark), manufactured by Chisso Corporation, average degree of polymerization 500) Component (D); Nn-butoxy Tylacrylamide 5 parts (manufactured by Kasano Kosan Co., Ltd.) Using this resin composition and carbon fibers having a tensile modulus of elasticity of 294 GPa, according to the above-mentioned method, setting the matrix resin content to 24% by weight, and setting the resin cured product and prepreg. Was prepared. The in-plane shear strength of CFRP obtained from the prepreg was 140 MPa, which satisfied the expression (1).

The average particle size of polyvinyl formal in CFRP was 3 μm.

Further, the crushing strength and impact strength of the cylindrical CFRP obtained by using this prepreg as the straight material and the bias material were good. Example 4 The following materials were mixed in a kneader to obtain a resin composition. Component (A): Bisphenol A type epoxy resin 40 parts ("Epicoat" 828 (registered trademark), manufactured by Yuka Shell Epoxy Co., Ltd.) Bisphenol A type epoxy resin 50 parts ("Epicoat" 1001 (registered trademark), oil) Shell Epoxy Co., Ltd.) Phenol novolak type epoxy resin 10 parts (“Epicoat” 154 (registered trademark), Yuka Shell Epoxy Co., Ltd.) Component (B); Dicyandiamide 5 parts (DICY7, Yuka Shell Epoxy) 3- (3,4-dichlorophenyl) -1,1-dimethylurea 3 parts (DCMU99, manufactured by Hodogaya Chemical Industry Co., Ltd.) Component (C); Polyvinylformal 7 parts (" Vinylek "K (registered trademark), manufactured by Chisso Corporation, average degree of polymerization 500) Component (D); N, N-diethyl 5 parts of acrylamide (produced by Kojin Co., Ltd.) Using this resin composition and carbon fibers having a tensile modulus of elasticity of 294 GPa, the resin cured product and the prepreg were prepared according to the method described above, with the matrix resin content being 24% by weight. Produced. The in-plane shear strength of CFRP obtained from the prepreg was 150 MPa, which satisfied the expression (1).

The average particle size of polyvinyl formal in CFRP was 3 μm.

Further, the crushing strength and impact strength of the cylindrical CFRP obtained by using this prepreg as a straight material and a bias material were good. Example 5 The following materials were mixed in a kneader to obtain a resin composition. Component (A): Bisphenol A type epoxy resin 40 parts ("Epicoat" 828 (registered trademark), manufactured by Yuka Shell Epoxy Co., Ltd.) Bisphenol A type epoxy resin 50 parts ("Epicoat" 1001 (registered trademark), oil) Phenol novolak type epoxy resin 10 parts ("Epicoat" 154 (registered trademark), Yuka Shell Epoxy Co., Ltd.) Component (B); Dicyandiamide 5 parts (DICY7, Yuka Shell Epoxy) 3- (3,4-dichlorophenyl) -1,1-dimethylurea 3 parts (DCMU99, manufactured by Hodogaya Chemical Industry Co., Ltd.) Component (C); Polyvinylformal 7 parts (" Vinylek "K (registered trademark), manufactured by Chisso Corporation, average degree of polymerization 500) Component (D); N-isopropyl 5 parts of acrylamide (produced by Kojin Co., Ltd.) Using this resin composition and carbon fibers having a tensile modulus of elasticity of 294 GPa, the resin cured product and the prepreg were prepared according to the method described above, with the matrix resin content being 24% by weight. Produced. The in-plane shear strength of CFRP obtained from the prepreg was 120 MPa, which satisfied the expression (1).

The average particle size of polyvinyl formal in CFRP was 3 μm.

Further, the crushing strength and impact strength of the cylindrical CFRP obtained by using this prepreg as the straight material and the bias material were good. Comparative Example 2 The following materials were mixed in a kneader to obtain a resin composition. Constituent element (A): bisphenol A type epoxy resin 10 parts (“Epicoat” 828 (registered trademark), manufactured by Yuka Shell Epoxy Co., Ltd.) bisphenol A type epoxy resin 40 parts (“epicoat” 1001 (registered trademark), oil) Shell Epoxy Co., Ltd.) Phenol novolak type epoxy resin 10 parts (“Epicoat” 154 (registered trademark), Yuka Shell Epoxy Co., Ltd.) Resorcin diglycidyl ether type epoxy resin 20 parts (“Denacol” EX201 (registered) Trade name), Nagase Kasei Kogyo Co., Ltd.) Brominated bisphenol A type epoxy resin 10 parts ("Epiclon" 152 (registered trademark), Dainippon Ink & Chemicals, Inc.) Component (B); Dicyandiamide 5 parts ( DICY7, manufactured by Yuka Shell Epoxy) Curing aid; 3- (3,4-di Lorophenyl) -1,1-dimethylurea 3 parts (DCMU99, manufactured by Hodogaya Chemical Industry Co., Ltd.) Component (C); polyvinyl formal 20 parts (“Vinilec” K (registered trademark), manufactured by Chisso Corporation, average polymerization) Using the resin composition and carbon fibers having a tensile modulus of elasticity of 294 GPa, a cured resin and a prepreg were prepared according to the method described above, with the matrix resin content being 24% by weight. The in-plane shear strength of CFRP obtained from the prepreg was 95 MPa, which did not satisfy the expression (1).

The average particle size of polyvinyl formal in CFRP was 15 μm.

Further, the crushing strength and impact strength of the cylindrical CFRP obtained by using this prepreg as a straight material and a bias material were poor. Comparative Example 3 The following materials were mixed in a kneader to obtain a resin composition. Component (A): bisphenol A type epoxy resin 30 parts ("Epicoat" 828 (registered trademark), manufactured by Yuka Shell Epoxy Co., Ltd.) bisphenol A type epoxy resin 40 parts ("epicoat" 1001 (registered trademark), oil) Shell Epoxy Co., Ltd.) 30 parts of phenol novolak type epoxy resin (“Epicoat” 154 (registered trademark), manufactured by Yuka Shell Epoxy Co., Ltd.) Component (B); 5 parts of dicyandiamide (DICY7, Yuka Shell Epoxy) 3- (3,4-dichlorophenyl) -1,1-dimethylurea 3 parts (DCMU99, manufactured by Hodogaya Chemical Industry Co., Ltd.) Component (C); polyvinyl formal 20 parts (“ (Vinilec®K (registered trademark), manufactured by Chisso Corp., average degree of polymerization: 500) Using carbon fibers 4 GPa, in accordance with the method described above, as a 24 weight percent matrix resin content, the cured resin, and to produce a prepreg. The in-plane shear strength of CFRP obtained from the prepreg was 89 MPa, which did not satisfy the expression (1).

The average particle size of polyvinyl formal in CFRP was 18 μm.

The crushing strength and impact strength of the cylindrical CFRP obtained by using this prepreg as a straight material and a bias material were poor. Example 6 The following materials were mixed in a kneader to obtain a resin composition. Component (A): bisphenol A type epoxy resin 65 parts (“Epicoat” 828 (registered trademark), manufactured by Yuka Shell Epoxy Co., Ltd.) bisphenol A type epoxy resin 25 parts (“epicoat” 1001 (registered trademark), oil) Phenol novolak type epoxy resin 10 parts ("Epicoat" 154 (registered trademark), Yuka Shell Epoxy Co., Ltd.) Component (B); Dicyandiamide 5 parts (DICY7, Yuka Shell Epoxy) 3- (3,4-dichlorophenyl) -1,1-dimethylurea 3 parts (DCMU99, manufactured by Hodogaya Chemical Industry Co., Ltd.) Component (C); polyvinyl formal 2 parts (“ Vinylect "E (registered trademark), manufactured by Chisso Corporation, average degree of polymerization 1300) Component (D); Nn-butoki Methylacrylamide 5 parts (manufactured by Kasano Kosan Co., Ltd.) Using this resin composition and carbon fiber having a tensile modulus of elasticity of 294 GPa, according to the above-mentioned method, setting the matrix resin content to 24% by weight, and setting the resin cured product and prepreg. Was prepared. The in-plane shear strength of CFRP obtained from the prepreg was 132 MPa, which satisfied the expression (1).

The average particle size of polyvinyl formal in CFRP was 5 μm.

The crushing strength and impact strength of the cylindrical CFRP obtained by using this prepreg as a straight material and a bias material were good. (Example 7) A prepreg was produced using the same resin composition as in Example 3 and carbon fibers having a tensile modulus of elasticity of 377 GPa according to the above-mentioned method with a matrix resin content of 24% by weight. CFRP obtained from prepreg
Had an in-plane shear strength of 92 MPa, which satisfied the expression (1).

The average particle size of polyvinyl formal in CFRP was 3 μm.

The crushing strength and impact strength of the cylindrical CFRP obtained by using the prepreg of Example 3 as a straight material and this prepreg as a bias material were good. (Comparative Example 4) A prepreg was prepared using the same resin composition as in Comparative Example 3 and carbon fibers having a tensile modulus of 377 GPa, according to the method described above, with a matrix resin content of 24% by weight. CFRP obtained from prepreg
Had an in-plane shear strength of 68 MPa, which did not satisfy the expression (1).

The average particle size of polyvinyl formal in CFRP was 18 μm.

The crushing strength and impact strength of the cylindrical CFRP obtained by using the prepreg of Comparative Example 3 as a straight material and the prepreg as a bias material, respectively, were poor. (Example 8) A prepreg was prepared using the same resin composition as in Example 3 and carbon fiber having a tensile modulus of 475 GPa, according to the method described above, with a matrix resin content of 24% by weight. CFRP obtained from prepreg
Had an in-plane shear strength of 90 MPa, which satisfied the expression (1).

The average particle size of polyvinyl formal in CFRP was 3 μm.

The crushing strength and impact strength of the cylindrical CFRP obtained by using the prepreg of Example 3 as a straight material and this prepreg as a bias material, respectively, were good. (Comparative Example 5) A prepreg was prepared using the same resin composition as in Comparative Example 3 and carbon fibers having a tensile modulus of 475 GPa according to the method described above, with a matrix resin content of 24% by weight. CFRP obtained from prepreg
Had an in-plane shear strength of 55 MPa, which did not satisfy the expression (1).

The average particle size of polyvinyl formal in CFRP was 18 μm.

Further, the crushing strength and impact strength of the cylindrical CFRP obtained by using the prepreg of Comparative Example 3 as a straight material and this prepreg as a bias material were poor. (Example 9) A prepreg was prepared using the same resin composition as in Example 3 and carbon fiber having a tensile modulus of elasticity of 539 GPa and a matrix resin content of 33% by weight according to the method described above. CFRP obtained from prepreg
Had an in-plane shear strength of 63 MPa, which satisfied the expression (1).

Further, the average particle size of polyvinyl formal in CFRP was 3 μm.

The crushing strength and impact strength of the cylindrical CFRP obtained by using the prepreg of Example 3 as a straight material and this prepreg as a bias material, respectively, were good. (Comparative Example 6) A prepreg was prepared using the same resin composition as in Comparative Example 3 and carbon fibers having a tensile elasticity of 539 GPa, according to the method described above, with a matrix resin content of 33% by weight. CFRP obtained from prepreg
Had an in-plane shear strength of 45 MPa, and did not satisfy Expression (1).

Further, the average particle size of polyvinyl formal in CFRP was 18 μm.

Further, the crushing strength and impact strength of the cylindrical CFRP obtained by using the prepreg of Comparative Example 3 as a straight material and the prepreg as a bias material, respectively, were poor.

[0163]

[Table 1]

[0164]

[Table 2]

[0165]

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

Since the prepreg of the present invention has high in-plane shear strength, a CFRP tubular body having excellent crushing strength and impact strength and light weight can be obtained.

The prepreg and CFRP according to the present invention
Golf club shafts, fishing rods, bicycle frames,
Badminton racket shaft, bicycle frame
It can be suitably used for a handle, a wheelchair frame, a hockey stick, and the like.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F072 AA02 AA07 AB10 AD08 AD24 AD25 AD28 AD29 AE01 AG03 AJ04 AL04 AL16 AL17 4J002 BE062 CD011 CD051 CD061 CD131 CL002 CM042 CN032 EL136 EN026 EN046 EN076 EN097 EN107 EN117 EP017 ET006 EU0 EV27 FD157 FD207 GC00 GL00 GM00 4J036 AC01 AD04 AD05 AD08 AD09 AF06 AH07 AH18 AJ17 DC02 DC06 DC21 DC31 DC41 FB02 FB13 FB14 FB15 JA11

Claims (7)

[Claims] 1. A carbon fiber, comprising the following components (A):
A prepreg impregnated with an epoxy resin composition containing (B), (C) and (D), wherein the component (C) is a carbon fiber reinforced composite material obtained by curing the prepreg. A prepreg characterized by being dispersed with an average particle size of 10 μm or less. (A) Epoxy resin (B) Curing agent (C) Thermoplastic resin (D) Epoxy resin (A) or curing agent (B) in the molecule
Having one functional group and one or more amide bonds capable of reacting with 2. The composition according to claim 1, wherein the component (C) has an average particle size of 5 in the carbon fiber reinforced composite material obtained by curing the prepreg.
The prepreg according to claim 1, wherein the prepreg is dispersed at a particle size of not more than μm. 3. Component (C) having an average degree of polymerization of 2
The prepreg according to claim 1, wherein the prepreg is a polyvinyl formal resin having a molecular weight of 000 or less. 4. Component (C) having an average degree of polymerization of 1
A polyvinyl formal resin having a molecular weight of 000 or less.
The prepreg according to the above. 5. The functional group capable of reacting with the epoxy resin (A) or the curing agent (B) in the component (D) is a carboxyl group, a phenolic hydroxyl group, an amino group, a secondary amine structure, a mercapto group, or an epoxy group. The prepreg according to any one of claims 1 to 4, wherein the prepreg is at least one selected from the group consisting of: and a double bond conjugated to a carbonyl group. 6. A carbon fiber reinforced composite material obtained by curing a prepreg, wherein the matrix resin content Wr (% by weight) of the carbon fiber reinforced composite material obtained by curing the prepreg, the tensile modulus E (GPa) of the carbon fiber, and the prepreg are cured. The prepreg according to any one of claims 1 to 5, wherein the in-plane shear strength S (MPa) of the material satisfies the following formulas (1) and (2). S ≧ −205 × LOG (E) +610 (1) 15 ≦ Wr ≦ 40 (2) 7. A carbon fiber reinforced composite material obtained by curing the prepreg according to claim 1. Description: