JPH11171972A - Epoxy resin composition for fiber-reinforced composite material, prepreg and fiber-reinforced composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition that gives the cured products excellent elongation and elasticity and is useful in the sports purposes as golf club shafts and the like, in the aerospace field, in the general industries by using a specific epoxy resin and a curing agent. SOLUTION: This epoxy resin composition includes (A) an epoxy resin mainly comprising (i) one or more kinds of an epoxy resins of formula I (n is 0 or more; Y is a 6-20C organic divalent group; X is a structure of formula II; m is 0 or more; Z is -CH2 - or the like) and (ii) one or more kinds of epoxy resins of formula III (R<1> -R<4> are each H, a halogen or the like) and (B) a curing agent such as dicyanadiamide. In a preferred embodiment, the amount of the component Ai is 5-50 wt.% and the component Aii is 10-60 wt.% based on the whole amount of the component A. As a component Ai, is cited a reaction product between a bis-phenol A type epoxy resin and tolylene diisocyanate, while the component Aii is, for example, resorcinol glycidyl ether or like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a resin composition for a fiber-reinforced composite material having excellent elongation and elastic modulus of a cured product, a prepreg using the same, and a 0-degree compressive strength obtained by using the same. And a 90-degree tensile elongation.

[0002]

2. Description of the Related Art Fiber-reinforced composite materials using a prepreg composed of a reinforcing fiber and a matrix resin as an intermediate base material have excellent mechanical properties, and are particularly suitable for use in sports, aerospace and general industrial applications. Widely used. Especially for sports applications, golf shafts, fishing rods,
Rackets such as tennis and badminton, and sticks such as hockey are mentioned as important applications.

[0003] 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 product is obtained by heating.

[0005] Sports fiber reinforced composites,
Golf shafts, fishing rods, and the like are fields where weight reduction is particularly required, but as a premise of weight reduction, it is necessary to increase the strength of the material.

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

[0007] However, a precise analysis of the destruction phenomena of golf shafts and fishing rods, especially of their light weight varieties, has revealed that the strength of carbon fiber alone is not always sufficient.

[0008] Golf shafts and fishing rods are usually constructed by winding and laminating several layers of unidirectional prepregs in different directions. If such a composite material breaks down,
The fracture mode changes depending on the composition of the material and how external force is applied (bending, twisting, etc.), but compression of either layer by 0 degree (parallel to the reinforcing fiber) or 90 degrees (reinforcement fiber within the layer) In most cases, one of the fracture modes of tension is the dominant factor.

[0009] Of these, the 0-degree compressive strength depends on the compressive strength of the reinforcing fiber, but also on the elastic modulus of the matrix resin. As the elastic modulus of the matrix resin increases, the compressive strength of the composite material increases. When the 0 degree compression is dominant, the composite strength increases.

In the failure mode in which 90-degree tension is dominant, 9
The greater the tensile elongation in the 0 degree direction, the higher the strength of the composite. The 90-degree tensile elongation of the composite depends on the elongation of the matrix resin.

Therefore, it is effective to improve both the elastic modulus and the elongation of the matrix resin in order to constantly obtain a high composite material strength independently of the material structure and external force. There is a trade-off between the modulus of elasticity and the elongation, and it is difficult to increase them simultaneously.

[0012]

SUMMARY OF THE INVENTION In view of the above-mentioned problems in the prior art, the present invention provides a resin composition for a fiber-reinforced composite material, which has both excellent elongation and elastic modulus of a cured product, and a prepreg using the same. An object of the present invention is to provide a fiber-reinforced composite material having excellent 0-degree compression strength and 90-degree tensile elongation obtained by using the same.

[0013]

The present invention employs the following means to solve the above-mentioned problems.
That is, the epoxy resin composition for a fiber-reinforced composite material of the present invention is a composition comprising at least an epoxy resin and a curing agent, and the epoxy resin component is mainly composed of the following components [A] and [B]. It is characterized by containing.

[A]: at least one epoxy resin represented by the following general formula (I)

Embedded image (In the formula, n is an integer of 0 or more, Y is an organic divalent group having 6 to 20 carbon atoms, X represents the following structure,

Embedded image In the formula, m is an integer of 0 or more, and Z is -CH _2- , -CH (CH
₃ ) A divalent group selected from-, -C (CH ₃ ) ₂ -and -SO _2- . [B]: at least one epoxy resin selected from epoxy resins represented by the following general formulas (II) to (IV)

Embedded image (In the formula, R ^{1 to} R ⁴ each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 8 carbon atoms.)

Embedded image (In the formula, R ^{7 to} R ⁸ each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 8 carbon atoms.)

Embedded image

Embedded image

Embedded image The epoxy resin composition for a fiber-reinforced composite material of the present invention is a composition comprising at least one epoxy resin represented by the general formula (I) and a curing agent.
The cured product obtained by curing at 0 ° C. for 2 hours has a tensile elongation of 8
%, And the flexural modulus is 3.3 GPa or more.

The prepreg of the present invention is characterized in that the epoxy resin composition for a fiber-reinforced composite material is impregnated with reinforcing fibers, and the fiber-reinforced composite material of the present invention comprises: It comprises a cured product of the epoxy resin composition for a fiber-reinforced composite material and a reinforcing fiber.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention has been made with an intensive study on an excellent fiber reinforced composite material which simultaneously satisfies the above-mentioned problems, that is, 0 ° compressive strength and 90 ° tensile elongation. By adopting a combination with the above, it has been found that such a problem can be solved at once.

The epoxy resin has the following configuration in order to achieve both elongation and elastic modulus. In the present invention, the epoxy resin means a compound having two or more epoxy groups in one molecule.

First, in order to obtain elongation, it is effective to lower the crosslinking density and to increase the distance between crosslinking points. First, in order to lower the crosslinking density, it is effective to use a bifunctional epoxy resin as a main component. Specifically, 70 to 100% by weight of the total epoxy resin component is 2%.
It is preferably a functional epoxy resin, and 80 to 100
More preferably, the weight% is a bifunctional epoxy resin.

In order to increase the distance between crosslinking points, it is advantageous to use a bifunctional epoxy resin having a large distance between two epoxy groups. However, even with a bifunctional epoxy resin having a large distance between two epoxy groups, for example, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, dimer acid diglycidyl ester, etc. have a remarkable effect of increasing elongation, The elastic modulus and heat resistance are significantly reduced, which is not suitable for the purpose of the present invention. As a component for improving the elongation without impairing the elastic modulus and heat resistance, an epoxy resin represented by the general formula (I) is preferable.

The epoxy resin represented by the general formula (I) includes an epoxy resin represented by the following general formula (VII) and an epoxy resin represented by the following general formula:
The diisocyanate represented by (VIII) is used as a catalyst such as a tertiary amine, a quaternary ammonium salt, a quaternary phosphonium salt, a cycloamidine or a salt thereof, a metal chloride / phosphine oxide, a boron trifluoride amine complex, or a fiber metal chelate complex. Obtained by heating in the presence. The conditions for the reaction of forming an oxazolidone ring from an epoxy compound and an isocyanate are described in U.S. Pat. Nos. 3,313,747, 3,334,110 and 3,702,839.
No., U.S. Pat.No. 3,721,650, U.S. Pat.
37406, JP-A-48-103570, JP-A-49-3
It is disclosed in a number of documents such as JP-A-7999, JP-A-49-94798, JP-A-49-93491, JP-A-50-136398, and JP-A-50-117771.

[0021]

Embedded image (Where m is an integer of 0 or more, and Z is -CH _2- ,
It is a divalent group selected from -CH (CH ₃ )-, -C (CH ₃ ) ₂ -and -SO _2- . OCN-Y-NCO (VIII) (wherein, Y is an organic divalent group having 6 to 20 carbon atoms.) A general formula which is a raw material of the epoxy resin represented by the general formula (I)
As specific examples of the epoxy resin represented by (II), the following bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin can be used, and as the diisocyanate represented by the general formula (III), Can be used tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate.

Commercially available epoxy resins represented by the general formula (I) include XAC4151 manufactured by Asahi Ciba, which is a reaction product of a bisphenol A type epoxy resin and tolylene diisocyanate.
(Epoxy equivalent 412), XAC4152 (epoxy equivalent 33
8) Alternatively, ACR epoxy from ACR
R-1206 (epoxy equivalent: 200) and ACR epoxy R-1348 (epoxy equivalent: 350) manufactured by AC R Co. can be used. One or more epoxy resins represented by the general formula (I) may be used. The amount of the epoxy resin represented by the general formula (I) (when a plurality of types are used, the total thereof) is preferably 5 to 50% by weight based on the total epoxy resin.

In order to increase the elastic modulus, a polyfunctional epoxy resin having three or more functional groups or a compound having a rigid skeleton is used.
It is effective to incorporate a functional epoxy resin.

Since the compounding of the polyfunctional epoxy resin has a side effect of increasing the crosslink density and sacrificing elongation, the compounding amount is preferably in the range of 0 to 30% of the entire epoxy resin. Mixing such an epoxy resin having a rigid skeleton has the effect of improving the elastic modulus without sacrificing much elongation. As the epoxy resin having such a rigid skeleton, at least one selected from epoxy resins represented by the general formulas (II) to (IV) is used.

The epoxy resin represented by the general formula (II) is obtained by reacting resorcin, hydroquinone, pyrocatechol, or a substituent derivative thereof with epichlorohydrin. Commercially available epoxy resins represented by the general formula (II) include "Denacol" EX-201, a resorcinol diglycidyl ether (manufactured by Nagase Kasei Kogyo Co., Ltd., epoxy equivalent 118), and "Denacol", a hydroquinone diglycidyl ether. "EX-203 (manufactured by Nagase Kasei Kogyo Co., Ltd.
"Epototo" YDC-1312 which is an epoxy equivalent 112) and 2,5-di-t-butylhydroquinone diglycidyl ether
(Manufactured by Toto Kasei Co., epoxy equivalent 170-185) 2,3,5-
R which is trimethylhydroquinone diglycidyl ether
E-701 (Nippon Kayaku Co., Ltd., epoxy equivalent: 143) and the like can be used.

The epoxy resin represented by the general formula (III)
It is obtained by the reaction of epichlorohydrin with 4,4'-dihydroxybiphenyl or a derivative thereof. A commercially available epoxy resin represented by the general formula (III) is "Epicoat" YX40 which is 4,4'-dihydroxy-3,3 ', 5,5'-tetramethylbiphenyldiglycidyl ether.
00 (made by Yuka Shell Epoxy Co., epoxy equivalent 180-1
92), "Epicoat" YL61, which is a mixture of 4,4'-dihydroxy-3,3 ', 5,5'-biphenyldiglycidyl ether and 4,4'-dihydroxybiphenyldiglycidyl ether
21H (Yuika Shell Epoxy Co., epoxy equivalent 175)
Can be used.

The epoxy resin represented by the general formula (IV) is obtained by reacting tetrabromobisphenol A with epichlorohydrin. Commercial products of the epoxy resin represented by the general formula (IV) include “Epicoat” 5050 (manufactured by Yuka Shell Epoxy, epoxy equivalent: 380 to 41).
0), "Epiclon" 152 (Dainippon Ink and Chemicals, epoxy equivalent: 340-380), "Sumi-Epoxy" ESB-400T (Sumitomo Chemical, Epoxy equivalent: 380)
420), "Epototo" YBD-360 (Toto Kasei Co., Ltd.
Epoxy equivalents from 350 to 370) can be used.

The epoxy resin represented by the general formula (V) is obtained by reacting dihydroxynaphthalene with epichlorohydrin. As a commercially available epoxy resin represented by the general formula (V), "Epiclon" HP-4032H (manufactured by Dainippon Ink and Chemicals, epoxy equivalent 250), which is 1,6-dihydroxynaphthalenediglycidyl ether, is used. can do.

The epoxy resin represented by the general formula (VI) has 9,
Obtained by reacting 9-bis (4-hydroxyphenyl) fluorene with epichlorohydrin. Such a general formula (VI)
"Epon" is a commercially available epoxy resin represented by
HPT resin 1079 (manufactured by Shell, epoxy equivalent 25
0 to 260), ESF-300 (Nippon Steel Chemical Co., Ltd., epoxy equivalent: 246) and the like can be used.

The epoxy resin having a rigid skeleton has the general formula (I
As the epoxy resins represented by I) to (IV), one kind selected from these may be used, or a plurality of kinds may be used. General formula
The compounding amount of the epoxy resin selected from (II) to (IV) (total of plural kinds thereof) is 10 to 6 in the total epoxy resin.
It is preferably 0% by weight.

Other bifunctional epoxy resins preferably used in the present invention include bisphenol A type epoxy resin (epoxy resin obtained by the reaction of bisphenol A and epichlorohydrin) and bisphenol F type epoxy resin (bisphenol F and epoxy resin). Epoxy resins obtained by the reaction of epichlorohydrin), bisphenol S type epoxy resins (epoxy resins obtained by the reaction of bisphenol S with epichlorohydrin) and the like can be used.

Commercially available bisphenol A type epoxy resins include "Epicoat" 825, (epoxy equivalents 172 to 178), "Epicoat" 828 (epoxy equivalents 184 to 194), and "Epicoat" 834 (epoxy equivalents 230 to 270). , “Epicoat” 1001 (epoxy equivalent 450-500), “Epicoat” 1004
(Epoxy equivalent 875-975), "Epicoat" 10
09 (Epoxy equivalent: 2400-3300) (all manufactured by Yuka Shell Epoxy Co., Ltd.), "Epototo" YD-12
8 (Epoxy equivalents 184-194, Toto Kasei Co., Ltd.)
Manufactured), "Epiclon" 840 (epoxy equivalent 180-1
90), "Epiclon" 850 (epoxy equivalent 184-
194), "Epiclon" 830 (epoxy equivalent: 16
5 to 185), "Epiclon" 1050 (epoxy equivalent: 450 to 500) (Dai Nippon Ink Chemical Industry Co., Ltd.)
Manufactured by Sumitomo Chemical Co., Ltd.), "Sumi Epoxy" ELA-128 (epoxy equivalent: 184-194, manufactured by Sumitomo Chemical Co., Ltd.), DER331
(Epoxy equivalents 182 to 192, manufactured by Dow Chemical Co., Ltd.) and the like.

Commercially available bisphenol F type epoxy resins include “Epicoat” 806, (flat epoxy equivalent: 160 to 170), and “Epicoat” 807 (epoxy equivalent: 160 to 175) (above, oiled shell epoxy ( Co., Ltd.), "Epiclon" 830, (Epoxy equivalent 1
65-180, manufactured by Dainippon Ink and Chemicals, Inc.).

As a commercial product of bisphenol S type epoxy resin, "Denacol" EX-251 (Negase Kasei Kogyo Co., Ltd., epoxy equivalent: 189) can be used.

Examples of the polyfunctional epoxy resin that can be suitably used in the epoxy resin composition of the present invention include novolak type epoxy resins (epoxy resins obtained by reacting novolak and epichlorohydrin), tetrakis (glycidyloxyphenyl) ethane, and the like. Multifunctional glycidyl ether type epoxy resins such as tris (glycidyloxy) methane, and polyfunctional glycidylamine type epoxy resins such as tetraglycidyldiaminodiphenylmethane, triglycidylaminophenol, triglycidylaminocresol, and tetraglycidylxylylenediamine. Can be used.

As a commercially available product of such a volak type epoxy resin, “Epicoat” 152 (epoxy equivalent: 172 to
179), "Epicoat" 154 (epoxy equivalent 176)
181) (both manufactured by Yuka Shell Epoxy Co., Ltd.), D
ER438 (epoxy equivalents 176-181, manufactured by Dow Chemical Company), "Araldite" EPN1138 (epoxy equivalents 176-181, manufactured by Ciba), "Araldite" EP
N1139 (epoxy equivalent: 172 to 179, manufactured by Ciba) can be used. Commercially available tetraglycidyldiaminodiphenylmethane is "Sumiepoxy" ELM434
(Epoxy equivalent: 110 to 130, manufactured by Sumitomo Chemical Co., Ltd.) can be used. Commercial products of triglycidylaminophenol include Sumiepoxy “ELM120 (epoxy equivalent 118, manufactured by Sumitomo Chemical Co., Ltd.), which is a triglycidyl-m-aminophenol, and“ Araldite ”MY0510 (CibaGeigy), which is a triglycidyl-p-aminophenol. And epoxy equivalents of 94 to 107).

As the curing agent used in the epoxy resin composition of the present invention, for example, diaminodiphenylmethane,
Aromatic amines such as diaminodiphenylsulfone, aliphatic amines such as triethylenetetramine and isophoronediamine, imidazole derivatives, carboxylic acid anhydrides such as dicyandiamide, tetramethylguanidine, methylhexahydrophthalic anhydride, and adipic hydrazide Carboxylic acid hydrazide, carboxylic acid amide, polyphenol compound, polymercaptan, Lewis acid complex such as boron trifluoride ethylamine complex and the like can be used. Further, in the present invention, an adduct having a curing activity obtained by reacting these curing agents with an epoxy resin can also be used. Also, those obtained by microencapsulating these curing agents can be suitably used in order to enhance the storage stability of the prepreg.

These curing agents can be combined with an appropriate curing accelerator to increase the curing activity. As such a combination, for example, an example in which a urea derivative or an imidazole derivative is combined as a curing accelerator with dicyandiamide, an example in which a tertiary amine or an imidazole derivative is combined with a carboxylic anhydride or a polyphenol compound as a curing accelerator is preferably used. Can be.

As the urea derivative, a compound obtained by reacting a secondary amine with an isocyanate, for example, 3
-Phenyl-1,1-dimethylurea, 3- (3,4-dichlorophenyl) -1,1-dimethylurea (DCM
U), 3- (3-chloro-4-methylphenyl) -1,
1-dimethylurea, 2,4-bis (3,3-dimethylureido) toluene and the like are preferably used.

In the epoxy resin composition of the present invention, in addition to the epoxy resin and the curing agent, other components such as a polymer compound and organic or inorganic particles can be blended as optional components.

As such a polymer compound, a thermoplastic resin soluble in an epoxy resin is preferably used. By blending the thermoplastic resin, the effect of controlling the viscosity of the resin, controlling the handleability of the prepreg, or improving the adhesion between the matrix resin and the reinforcing fibers is improved. The thermoplastic resin used here is particularly preferably a thermoplastic resin having a hydrogen-bonding functional group in terms of compatibility with the epoxy resin and adhesiveness with the reinforcing fiber. As such a hydrogen bonding functional group, an alcoholic hydroxyl group, an amide group, an imide group, a sulfonyl group and the like can be used. Examples of the thermoplastic resin having an alcoholic hydroxyl group include polyvinyl acetal resins such as polyvinyl formal and polyvinyl butyral, phenoxy resins, and the thermoplastic resin having an amide group include polyamide; and the thermoplastic resins having an imide group include polyimide and sulfonyl. Polysulfone or the like can be used as the thermoplastic resin having a group. Such 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.

Examples of commercially available thermoplastic resins having a hydrogen bonding functional group which are soluble in an epoxy resin include polyvinyl acetal resins such as "Denka Butyral" and "Denka Formal" (manufactured by Denki Kagaku Kogyo Co., Ltd.).
"VINYLEC" (manufactured by Chisso Corporation), "UCAR" PKHP (manufactured by Union Carbide) as a phenoxy resin, "Macromelt" (manufactured by Henkel Hakusui Corporation) as a polyamide resin, "Amilan" CM4000 (manufactured by Toray Industries, Inc.) "Ultem" (manufactured by General Electric) as polyimide, "Matrimid" 5
218 (manufactured by Ciba) as a polysulfone “Victr
ex "(manufactured by Mitsui Toatsu Chemicals, Inc.) and" UDEL "(manufactured by Union Carbide) can be used.

When a thermoplastic resin is contained, it is preferred that the thermoplastic resin be contained in an amount of 1 to 20 parts by weight with respect to 100 parts by weight of the epoxy resin, so that the epoxy resin composition has an appropriate viscoelasticity and a good composite material. It is preferable because physical properties can be obtained.

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 resin and the impact resistance of the fiber-reinforced composite material.

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

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

Examples of commercially available core-shell rubber particles include, for example, “paraloid” EXL-2655 (made by Kureha Chemical Industry Co., Ltd.) composed of butadiene / alkyl methacrylate / styrene copolymer, and acrylate / methacrylate copolymer. "STAPHYLOID" AC-335
5, “PAR-2” comprising TR-2122 (manufactured by Takeda Pharmaceutical Co., Ltd.) and butyl acrylate / methyl methacrylate copolymer
ALOID "EXL-2611, EXL-3387 (R
ohm & Haas) can be used.

As the thermoplastic resin particles, polyamide or polyimide particles are preferably used. As commercially available polyamide particles, Toray SP-500, ATOCHE
"Orgasol" manufactured by M Company can be used.

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.

The resin composition for a fiber-reinforced composite material of the present invention is characterized by high elongation and elastic modulus of a cured product. Specifically, the cured product obtained by curing at 130 ° C. for 2 hours preferably has a tensile elongation of 8% or more, more preferably 10% or more. The flexural modulus of the cured product obtained by curing under the same conditions is preferably 3.3 GPa or more, and more preferably 3.5 GPa or more.

As the reinforcing fibers used in the fiber-reinforced composite material of the present invention, glass fibers, carbon fibers, aramid fibers, boron fibers, alumina fibers, silicon carbide fibers and the like are preferably used. Two or more of these fibers may be used in combination, but carbon fibers are particularly preferably used to obtain a lighter and more durable molded product. In order to produce lighter sporting goods such as golf shafts and fishing rods, it is preferable to use carbon fibers having a high elastic modulus for the prepreg so that a small amount of material can express sufficient rigidity of the product. As such a carbon fiber, one having an elastic modulus of preferably 200 GPa or more, more preferably 210 to 800 GPa is used.

The fiber-reinforced composite material of the present invention is produced by various known methods. For example, a prepreg in which a reinforcing fiber is impregnated with an epoxy resin composition is prepared in a method suitable for manufacturing sports goods such as golf shafts, fishing rods, rackets, and the like, and this is laminated and heat-cured to obtain a fiber-reinforced composite material. A method or the like can be adopted. Also,
The form and arrangement of the reinforcing fibers used in the prepreg are not particularly limited, and for example, long fibers aligned in one direction, a single tow, a woven fabric, a mat, a knit, a braid, and the like are used.
The prepreg is manufactured 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 is impregnated, and a hot melt method (dry method) in which the viscosity is reduced by heating and impregnated. You. The wet method is a method in which a reinforcing fiber is immersed in an epoxy resin composition solution, then 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 a reinforcing fiber with an epoxy resin composition whose viscosity has been reduced by heating, or first preparing a film in which the epoxy resin composition is coated on release paper or the like, and then reinforcing the film. 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 the composite using the prepreg can be carried out by laminating the prepreg and then heating and curing the resin while applying pressure to the laminate.

Methods for applying heat and pressure include 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 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 object, and is suitable for producing a rod-shaped body such as a golf shaft and a fishing rod. Specifically, the prepreg is wound around the mandrel, and for fixing the prepreg and applying pressure,
A wrapping tape made of a thermoplastic resin film is wrapped around the outside of the prepreg, and the resin is heated and cured in an oven, and then the core is removed 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 shaft, a bat, a racket such as tennis or badminton.

Further, a method of directly impregnating a reinforcing fiber with the epoxy resin composition of the present invention without using a prepreg, followed by heat curing, such as a hand lay-up method, a filament winding method, a pultrusion method, and a resin
A fiber-reinforced composite material can also be produced by a molding method such as an injection molding method or a resin transfer molding method. In these, a method of preparing a resin composition by mixing two liquids of a main agent composed of an epoxy resin and a curing agent immediately before use can be adopted.

[0059]

The present invention will be described in more detail with reference to the following examples. The measurement of tensile elongation and flexural modulus of the cured resin, preparation of prepreg, preparation of fiber reinforced composite material, and measurement of 0 ° compression strength and 90 ° tensile elongation were performed under the following conditions.

A. Measurement of Tensile Elongation of Cured Resin The resin composition was heated to 80 ° C. and injected into a mold.
The resin was cured in an oven at 30 ° C. for 2 hours to prepare a resin cured product plate having a thickness of 2 mm. Next, JI from the cured resin plate
According to S-K7113, a small 1 (1/2) type test piece was cut out and the tensile elongation was determined.

B. Measurement of Flexural Modulus of Cured Resin The resin composition was heated to 80 ° C and injected into a mold.
The resin was cured in an oven at 30 ° C. for 2 hours to prepare a cured resin plate having a thickness of 2 mm. Next, a test piece having a width of 10 mm and a length of 60 mm was cut out from the cured resin plate, and three-point bending with a span of 32 mm was measured. The bending elastic modulus was determined according to JIS-K7203.

C. Preparation of Prepreg An 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 “Treca” M30GC (manufactured by Toray Industries, Inc.) having a tensile modulus of 294 GPa arranged in one direction in a sheet shape, and the resin is impregnated with heat and pressure. A unidirectional prepreg having a carbon fiber weight of 125 g / m ² and a matrix resin having a weight fraction of 24% was prepared.

D. Preparation of fiber-reinforced composite material After laminating a predetermined number of unidirectional prepregs so that the directions of the reinforcing fibers are the same, use an autoclave at 135 ° C for 2 hours.
The molding was performed at a time of 0.29 MPa (3 kgf / cm ² ) to obtain a fiber-reinforced composite material plate.

E. Measurement of 0 degree compressive strength of fiber reinforced composite material From a plate of fiber reinforced composite material obtained by laminating 11 unidirectional prepregs, according to ASTM D695, width 12.7 mm, length 79.4 mm
Was prepared, and the compressive strength was measured.

F. Measurement of 90-degree tensile elongation of fiber-reinforced composite material From a plate of fiber-reinforced composite material obtained by laminating 21 unidirectional prepregs, according to ASTM D3039, width 25.4 mm, length 38.1 mm
Was prepared, a tensile test was performed, and the elongation was determined.

Examples 1 to 4 One epoxy resin represented by the general formula (I) containing 90% by weight of the bifunctional epoxy resin in the total epoxy resin, and one represented by the general formulas (II) to (VI) Resin compositions shown in Table 1 containing one or two kinds of epoxy resins selected from resins were prepared. The tensile elongation and flexural modulus of these cured resin products were measured. As shown in Table 1, each of the resins was used for 3.
It exhibited a high flexural modulus of 4 to 3.5 GPa and a high tensile elongation of 10 to 11%. Next, a unidirectional prepreg was prepared using these resins, and these were laminated and cured to prepare a fiber-reinforced composite material, and 0 ° compression strength and 90 ° tensile elongation were measured. The results are as shown in Table 1, 1.83 to
Shows high compressive strength of 1.85 MPa, 0.8-1.0%
High 90 ° tensile elongation.

Comparative Example 1 In Table 1 which consists of 65% of a bifunctional epoxy resin and 35% of a polyfunctional epoxy resin ("Epicoat" 154), and does not use the epoxy resin trees represented by the general formulas (I) to (VI). Was prepared. The tensile elongation of the cured resin using this was as low as 3%, and the flexural modulus was 3.2 GPa, which was moderate. A unidirectional prepreg was prepared using this resin, and these were laminated and cured to prepare a fiber-reinforced composite material, and 0 ° compression strength and 90 ° tensile elongation were measured. As shown in Table 1, the compressive strength was 1.70 MPa, and the 90 ° tensile elongation was 0.6.
% Were all moderate values.

[0068]

[Table 1]

[0069]

According to the present invention, an excellent fiber-reinforced composite material can be stably provided as a material for an extremely wide range of uses such as sports use, aerospace use and general industrial use.

Claims (7)

[Claims] 1. A fiber comprising at least an epoxy resin and a curing agent, wherein the epoxy resin component mainly comprises the following components [A] and [B]: Epoxy resin composition for reinforced composite materials. [A]: at least one epoxy resin represented by the following general formula (I): (Wherein n is an integer of 0 or more, Y is an organic divalent group having 6 to 20 carbon atoms, X represents the following structure, In the formula, m is an integer of 0 or more, and Z is -CH _2- , -CH (CH
₃ ) A divalent group selected from-, -C (CH ₃ ) ₂ -and -SO _2- . [B]: at least one epoxy resin selected from epoxy resins represented by the following general formulas (II) to (IV): (In the formula, R ^{1 to} R ⁴ each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 8 carbon atoms.) (In the formula, R ^{7 to} R ⁸ each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 8 carbon atoms.) Embedded image Embedded image 2. The epoxy resin composition for a fiber-reinforced composite material according to claim 1, wherein the bifunctional epoxy resin component is contained in an amount of 70 to 100% by weight based on all epoxy resin components in the composition. . 3. The epoxy resin composition for a fiber-reinforced composite material according to claim 1, wherein the component [A] in the bifunctional epoxy resin component is contained in an amount of 5 to 50% by weight based on the total epoxy resin component. Stuff. 4. The fiber-reinforced composite material according to claim 1, wherein the component [B] in the bifunctional epoxy resin component is contained in an amount of 10 to 60% by weight based on the entire epoxy resin component. Epoxy resin composition for use. 5. At least one compound represented by the following general formula (I)
A composition comprising a kind of epoxy resin and a curing agent,
When the composition was cured at 130 ° C. for 2 hours, the cured product had a tensile elongation of 8% or more and a flexural modulus of 3.3 GPa.
An epoxy resin composition for a fiber-reinforced composite material, characterized in that: Embedded image (Wherein n is an integer of 0 or more, Y is an organic divalent group having 6 to 20 carbon atoms, X represents the following structure, In the formula, m is an integer of 0 or more, and Z is -CH _2- , -CH (CH
₃ ) A divalent group selected from-, -C (CH ₃ ) ₂ -and -SO _2- . ) 6. A prepreg characterized by comprising a reinforcing fiber impregnated with the epoxy resin composition according to any one of claims 1 to 5. 7. A fiber-reinforced composite material comprising a cured product of the epoxy resin composition according to claim 1 and reinforcing fibers.