JP2001278949A - Epoxy resin composition, prepreg and fiber reinforced composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin composition that is excellent in tbe elastic modulus and a tensile elonganation of a resin hardening material and to provide a prepreg by applying this, further more, to provide a fiber reinforced composite material that is excellent in the compressive strength in 0 deg. and the tensile elonganation in 90 deg. that applies this epoxy resin composition and a reinforced fiber as a composition element. SOLUTION: The epoxy resin composition contains composition elements [A] and [B] and a hardening agent [A]: The epoxy resin has an oxazolidone ring in the molecule and an epoxy resin having two epoxy groups [B]: The epoxy resin is shown by the specific structural formula.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an epoxy resin composition, a prepreg, and a fiber-reinforced composite material.

[0002]

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 is lightweight and has excellent mechanical properties, so that it is used in sports applications, aerospace applications, 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.

In sports applications, carbon fibers are mainly used as reinforcing fibers, and epoxy resins are mainly used as matrix resins.

[0004] The fiber-reinforced composite material is produced by various methods, and in many cases, a prepreg, which is a sheet-like intermediate substrate in which a matrix resin is impregnated in a reinforcing fiber, is interposed. In this method, a fiber-reinforced composite material is obtained by laminating a plurality of prepregs and then heating.

A fiber-reinforced composite material for sports, that is, a golf shaft, a fishing rod, etc. is an area where weight reduction is particularly required. It is important to increase the strength of the material together with the weight reduction.

[0006] For this reason, the prior art has focused on improving the strength of reinforcing fibers, mainly carbon fibers. However, if the fracture phenomena of golf shafts and fishing rods, especially lightweight varieties among them, are precisely analyzed, simply carbon fiber It has become clear that the strength of the material cannot be increased as much as expected simply by improving the strength of the material.

[0007] Golf shafts and fishing rods are usually manufactured by winding several layers of unidirectional prepregs in different directions and laminating them.

[0008] Such a cylindrical composite material is broken differently depending on the composition of the material and how the external force is applied (bending, twisting, etc.). Breakage often progresses due to either a compressive stress or a tensile stress of 90 degrees (a direction perpendicular to the reinforcing fibers in the layer) as a main factor.

The 0-degree compressive strength depends not only on the compressive strength of the reinforcing fibers but also on the elastic modulus of the matrix resin. Therefore, when the elastic modulus of the matrix resin is increased, the compressive strength of the fiber-reinforced composite material is increased, and when compression in the 0-degree direction is a main factor of destruction, its fracture resistance is increased.

On the other hand, in the case where tensile in the 90-degree direction is the main cause of fracture, the greater the tensile elongation in the 90-degree direction of the fiber-reinforced composite material, the higher its fracture resistance. The tensile elongation in the 90-degree direction depends on the tensile elongation of the matrix resin.

Therefore, in order to obtain a fiber-reinforced composite material exhibiting high strength without depending on the material composition and how external force is applied, it is necessary to improve both the elastic modulus and the tensile elongation of the matrix resin. A fiber-reinforced composite that is particularly suitable for sports equipment such as golf shafts and fishing rods that exhibits excellent resistance to fracture stress from various directions because the modulus and tensile elongation of the matrix resin are in a trade-off relationship. Materials have heretofore been difficult to obtain.

[0012]

SUMMARY OF THE INVENTION In view of the problems of the prior art, an object of the present invention is to provide an epoxy resin composition having excellent elastic modulus and tensile elongation of a cured resin, a prepreg using the same, and a prepreg using the same. It is intended to provide a fiber-reinforced composite material having excellent 0-degree compressive strength and 90-degree tensile elongation obtained by using the same.

[0013]

In order to solve the above problems, the epoxy resin composition of the present invention has the following constitution. That is, the epoxy resin composition contains the following components [A] and [B] and a curing agent. [A]: an epoxy resin having an oxazolidone ring and two epoxy groups in the molecule [B]: an epoxy resin represented by the following general formula (I), (II) or (III)

[0014]

Embedded image

(Wherein, R ^{1 to} R ⁴ are each a substituent selected from hydrogen, halogen, and an alkyl group having 1 to 8 carbon atoms.)

[0016]

Embedded image

(Wherein, R ^{5 to} R ⁸ are each a substituent selected from hydrogen, halogen, and an alkyl group having 1 to 8 carbon atoms.)

[0018]

Embedded image

(In the formula, R ^{9 to} R ¹³ are each a substituent selected from hydrogen, halogen, and an alkyl group having 1 to 8 carbon atoms.) The prepreg according to the present invention has the following structure. That is, it is a prepreg obtained by impregnating reinforcing fibers with the epoxy resin composition.

Further, the fiber-reinforced composite material according to the present invention has the following constitution. That is, a cured product of the epoxy resin composition and a fiber-reinforced composite material containing reinforcing fibers as constituent elements.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Component [A] in the present invention
Is an epoxy resin having an oxazolidone ring and two epoxy groups in the molecule, and preferably has the following general formula (I
The epoxy resin represented by V) is preferred.

[0022]

Embedded image

(Wherein, n is an integer of 0 or more, Y is a divalent organic group having 6 to 20 carbon atoms, and X is a substituent represented by the following formula.)

[0024]

Embedded image

(Where m is an integer of 0 or more, and Z is
_{-CH 2 -, - CH (CH} 3) -, - C (CH 3) 2 -, - it is a divalent substituent selected from - SO _2. The epoxy resin represented by the general formula (IV) may be, for example, an epoxy resin represented by the following general formula (V) and a diisocyanate represented by the following general formula (VI) as a tertiary amine or a quaternary amine. It can be obtained by heating in the presence of a catalyst such as an ammonium salt, a quaternary phosphonium salt, a cycloamidine or a salt thereof, a metal chloride / phosphine oxide, a boron trifluoride amine complex, and a fiber metal chelate complex.

[0026]

Embedded image

(Where m is an integer of 0 or more;
Is a divalent substituent selected from —CH ₂ —, —CH (CH ₃ ) —, —C (CH ₃ ) ₂ —, and —SO ₂ —. OCN-Y-NCO (VI) (wherein Y is a divalent organic group having 6 to 20 carbon atoms.) Here, specific examples of the epoxy resin represented by the general formula (V) will be described later. Bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, and the like. Examples of the diisocyanate represented by the general formula (VI) include tolylene dicysocyanate, 4,4′-
Examples thereof include diphenylmethane diisocyanate, xylylene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate.

In order to obtain the component [A] from the epoxy resin represented by the general formula (V) and the diisocyanate represented by the general formula (VI), for example, JP-A-48-103570
JP-A-49-37999, JP-A-49-37999
No. 94798, JP-A-49-93491, JP-A-50-136398, JP-A-50-1177
No. 71, U.S. Pat.No. 3,313,747, U.S. Pat.No. 3,334,110
, US Pat. No. 3,702,839, US Pat. No. 3,721,650, US Pat. No. 3,737,406, and the like.

As a commercial product of the epoxy resin represented by the general formula (VI), XAC4151 manufactured by Asahi Ciba, which is a reaction product of a bisphenol A type epoxy resin and tolylene diisocyanate is available.
(Epoxy equivalent 412), XAC4152 (epoxy equivalent 33
8) Or ACR epoxy R-C
1206 (epoxy equivalent: 200), ACR epoxy R-1348 (epoxy equivalent: 350) available from AC R, and the like can be used.

The epoxy resin represented by the general formula (VI)
One or more species may be used. The amount of the epoxy resin represented by the general formula (VI) (the total amount when a plurality of types are used) is 5 to 80% by weight, preferably 10 to 60% by weight, based on 100% by weight of the total epoxy resin. Is good. If it is less than 5% by weight, the tensile elongation of the matrix resin, that is, the cured product of the epoxy resin (hereinafter abbreviated as “resin cured product”) may decrease. May decrease.

The component [B] in the present invention is an epoxy resin represented by the following general formula (I), (II) or (III).

[0032]

Embedded image

(Wherein, R ^{1 to} R ⁴ are each a substituent selected from hydrogen, halogen, and an alkyl group having 1 to 8 carbon atoms.)

[0034]

Embedded image

(Wherein, R ^{5 to} R ⁸ are each a substituent selected from hydrogen, halogen, and an alkyl group having 1 to 8 carbon atoms.)

[0036]

Embedded image

(Wherein R ^{9 to} R ¹³ are each a substituent selected from hydrogen, halogen, and an alkyl group having 1 to 8 carbon atoms.) The epoxy resin represented by the general formula (I) is, for example, Phthalic acid, isophthalic acid, terephthalic acid or a derivative thereof can be obtained by reaction of epichlorohydrin, specifically, phthalic acid diglycidyl ester,
Examples include diglycidyl isophthalate and diglycidyl terephthalate.

The epoxy resin represented by the general formula (II) can be obtained, for example, by the reaction of hexahydrophthalic acid, hexahydroisophthalic acid, hexahydroterephthalic acid or a derivative thereof with epichlorohydrin. Specific examples include diglycidyl hexahydrophthalate, diglycidyl hexahydroisophthalate, and diglycidyl hexahydroterephthalate.

The epoxy resin represented by the general formula (III)
For example, it can be obtained by reacting aniline or a substituent derivative thereof with epichlorohydrin, and specific examples include N, N-diglycidylaniline, N, N-diglycidyl o-toluidine and the like.

The compounding amount of the component [B] (the total amount when plural kinds are used) is 10 to 60% by weight, preferably 20 to 50% by weight based on 100% by weight of the total epoxy resin.
It is good to make it by weight%. If it is less than 10% by weight, the elastic modulus of the cured resin may decrease, and if it exceeds 60% by weight, the tensile elongation of the cured resin may decrease.

Incidentally, a bifunctional epoxy resin other than the component [A] or the component [B] can be used. For example,
Bisphenol A epoxy resin (epoxy resin obtained by reaction of bisphenol A and epichlorohydrin), bisphenol F epoxy resin (epoxy resin obtained by reaction of bisphenol F and epichlorohydrin), bisphenol S epoxy resin ( Bifunctional epoxy resins other than the above-mentioned constituent elements [A] and [B], such as an epoxy resin obtained by the reaction of bisphenol S and epichlorohydrin, can also be used for each purpose (1 epoxy group per epoxy group). Called sensuality, for example,
(Epoxy resins having two epoxy groups in the molecule are referred to as bifunctional epoxy resins.) Hereinafter, the product name enclosed in "" indicates a registered trademark or an unregistered trademark.

Commercially available bisphenol A type epoxy resins include "Epicoat" 825 (epoxy equivalent 17
2-178) "Epicoat" 828 (epoxy equivalent 18
4-194), "Epicoat" 834 (epoxy equivalent 2
30 to 270), "Epicoat" 1001 (epoxy equivalent 450 to 500), "Epicoat" 1004 (epoxy equivalent 875 to 975), "Epicoat" 1009 (epoxy equivalent 2400 to 3300) (the above are Yuka Shell Epoxy Co., Ltd.) ), "Epototo" YD-128 (epoxy equivalents 184-194, manufactured by Toto Kasei Co., Ltd.), "Epiclon" 840 (epoxy equivalents 180-190), "Epiclon" 850 (epoxy equivalents 184-194),
"Epiclon" 830 (epoxy equivalent 165-18
5), "Epiclon" 1050 (epoxy equivalent 450-
500) (above, manufactured by Dainippon Ink and Chemicals, Inc.)
"Sumi Epoxy" ELA-128 (Epoxy equivalent 184
To 194, manufactured by Sumitomo Chemical Co., Ltd.), DER331 (epoxy equivalent: 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 16
0 to 170), "Epicoat" 807 (epoxy equivalent 1
60-175), “Epicoat” 4004P (epoxy equivalent 880), “Epicoat” 4007P (epoxy equivalent 2270), “Epicoat” 4010P (epoxy equivalent 4400) (all manufactured by Yuka Shell Epoxy Co., Ltd.),
"Epiclon" 830, (epoxy equivalent 165-18
0, manufactured by Dainippon Ink and Chemicals, Inc.).

Commercially available bisphenol S type epoxy resins include "Epiclone" EXA-1514 (epoxy equivalent 305), "Epiclone" EXA-4023 (epoxy equivalent 250), and "Epiclone" EXA-4031.
(Epoxy equivalent 210), (all manufactured by Dainippon Ink and Chemicals, Inc.) and the like can be used.

From the viewpoint of improving the tensile elongation of the cured resin, the amount of the bifunctional epoxy resin is 70 to 100% by weight, preferably 80 to 100% by weight, based on 100% by weight of the total epoxy resin. It is good to make it by weight%.

In the present invention, a bifunctional epoxy resin in which the distance between two epoxy groups in a molecule is particularly large, for example,
It is preferable to use a bifunctional epoxy resin having an epoxy equivalent of 350 or more. By using such a bifunctional epoxy resin, the distance between crosslinking points of the cured resin is further increased, and the tensile elongation of the cured resin is greatly improved.

The epoxy equivalent of the epoxy resin used is 4
It is good to be in the range of 00 to 10000, preferably 400 to 6000. If it exceeds 10,000, the heat resistance of the obtained fiber-reinforced composite material (hereinafter, simply referred to as composite material) may decrease, or the viscosity of the resin composition may increase, and the handleability of the prepreg may deteriorate.

In order to increase the modulus of elasticity of the cured resin,
An epoxy resin containing three or more epoxy groups in the molecule can also be blended.

The amount of the epoxy resin having three or more functional groups is set so that the cross-linking density is increased while the side effect of impairing the tensile elongation of the cured resin is effectively suppressed. The content is preferably 0 to 30% by weight, more preferably 0 to 10% by weight.

Specific examples of epoxy resins having three or more functional groups include, for example, novolak type epoxy resins (epoxy resins obtained by reacting novolak and epichlorohydrin), tetrakis (glycidyloxyphenyl) ethane, and tris (glycidyloxy). Examples include glycidyl ether type epoxy resins such as methane, and glycidylamine type epoxy resins such as tetraglycidyldiaminodiphenylmethane, triglycidylaminophenol, triglycidylaminocresol, and tetraglycidylxylylenediamine.

Commercial products of the novolak type epoxy resin include “Epicoat” 152 (epoxy equivalent of 172 to 17).
9), “Epicoat” 154 (epoxy equivalent 176-1)
81) (both manufactured by Yuka Shell Epoxy Co., Ltd.), DER
438 (epoxy equivalents 176-181, manufactured by Dow Chemical Co.), "Araldite" EPN1138 (epoxy equivalents 176-181, manufactured by Ciba), "Araldite" EPN
1139 (epoxy equivalents 172-179, manufactured by Ciba) or the like can be used.

As a commercially available tetraglycidyldiaminodiphenylmethane, “Sumiepoxy” ELM434 (manufactured by Sumitomo Chemical Co., Ltd., epoxy equivalent: 110 to 130) and the like can be used.

Commercial products of triglycidylaminophenol include "Sumiepoxy" ELM120 (epoxy equivalent 118, triglycidyl-m-aminophenol).
Sumitomo Chemical Co., Ltd.) and “araldite” MY0510, a triglycidyl-p-aminophenol (manufactured by Ciba,
Epoxy equivalents 94 to 107) and the like can be used.

Examples of the curing agent include aromatic amines such as diaminodiphenylmethane and diaminodiphenylsulfone, aliphatic amines such as triethylenetetramine and isophoronediamine, imidazole derivatives, dicyandiamide, tetramethylguanidine and methylhexahydrophthalic anhydride. Anhydrides, carboxylic acid hydrazides such as adipic hydrazide, carboxylic acid amides, polyphenol compounds, polymercaptans, Lewis acid complexes such as boron trifluoride ethylamine complex and the like can be used.

In the present invention, an addition compound (adduct compound) having a high curing activity and obtained by reacting these curing agents with an epoxy resin can also be used. Further, those in which these curing agents are microencapsulated are preferable from the viewpoint of improving the storage stability of the prepreg.

These curing agents may be used in combination with a curing accelerator in order to increase the curing activity of the resin. For example, examples include combining dicyandiamide with a urea derivative or an imidazole derivative as a curing accelerator, and combining carboxylic anhydride or a polyphenol compound with a tertiary amine or imidazole derivative as a curing accelerator.

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 ( DCMU), 3
-(3-chloro-4-methylphenyl)-1,1-dimethylurea, 2,4-bis (3,3-dimethylureido)
Toluene and the like are preferably used.

In the present invention, optional components such as a polymer compound, organic particles, and inorganic particles can be mixed with the epoxy resin composition according to the respective purposes.

As the polymer compound, a thermoplastic resin soluble in an epoxy resin is preferably used. By the addition of such a thermoplastic resin, controllability of the viscosity of the resin, handleability of the prepreg, or adhesion between the matrix resin and the reinforcing fibers are improved.

The thermoplastic resin soluble in the epoxy resin is preferably a thermoplastic resin having a hydrogen-bonding functional group from the viewpoint of compatibility with the epoxy resin and adhesion to the reinforcing fiber.

Examples of the hydrogen-bonding functional group include an alcoholic hydroxyl group, an amide group, an imide group and a sulfonyl group. Further, as the thermoplastic resin having an alcoholic hydroxyl group, polyvinyl acetal resin such as polyvinyl formal or polyvinyl butyral, phenoxy resin, etc., as the thermoplastic resin having an amide group, polyamide, etc., as the thermoplastic resin having an imide group, Examples of the thermoplastic resin having a sulfonyl group such as polyimide include polysulfone.

The polyamide, polyimide and polysulfone may have a functional group such as an ether bond and a carbonyl group in the main chain, and the polyamide may have a substituent at the nitrogen atom of the amide group.

Commercially available thermoplastic resins having a hydrogen-bonding functional group include, for example, polyvinyl acetal resins such as "Denka Butyral" and "Denka Formal" (manufactured by Denki Kagaku Kogyo Co., Ltd.) and "Vinilec" ( Chisso Corporation), “UCAR” P as phenoxy resin
KHP (manufactured by Union Carbide), polyamide resin "Macromelt" (manufactured by Henkel Hakusui Co., Ltd.), "Amilan" CM4000 (manufactured by Toray Industries, Inc.), polyimide "Ultem" (manufactured by General Electric), " Matrimid 5218 (manufactured by Ciba), polysulfone "Victrex" (manufactured by Mitsui Toatsu Chemicals, Inc.), "U
DEL "(manufactured by Union Carbide) or the like can be used.

In the present invention, the thermoplastic resin soluble in the epoxy resin gives the epoxy resin composition an appropriate viscoelasticity,
Since a high quality composite material can be obtained, all epoxy resin 100
1 to 20 parts by weight, preferably 1 to 10 parts by weight,
It is preferable to mix by weight.

In the present invention, organic particles such as rubber particles and thermoplastic resin particles can be blended with the epoxy resin composition in order to increase the toughness of the resin and the impact resistance of the obtained composite material.

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 from the viewpoint of handleability and the like.

Commercially available crosslinked rubber particles include XER-91 (manufactured by 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.) and YR-500 series (manufactured by Toto Kasei Co., Ltd.) composed of acrylic rubber fine particles can be used.

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 acrylic acid ester / methacrylic acid ester. "Staphyloid" AC- consisting of a polymer
3355, TR-2122 (manufactured by Takeda Pharmaceutical Co., Ltd.),
"PARALOID" made of butyl acrylate / methyl methacrylate copolymer EXL-2611, EXL-3387 (Rohm & Haas)
Etc. can be used.

As the thermoplastic resin particles, polyamide particles and polyimide particles are preferably used, and commercially available polyamide particles include SP-500, ATOC, manufactured by Toray Industries, Inc.
"Orgasol" manufactured by HEM can be used.

In the present invention, inorganic particles such as silica, alumina, smectite, and synthetic mica can be added to the epoxy resin composition for controlling rheology such as thickening of the resin composition and imparting thixotropic properties.

The epoxy resin composition according to the present invention is one in which the matrix resin, that is, the cured resin material, has both a high elastic modulus and a high tensile elongation at a high level. The cured resin obtained by curing has a tensile elongation of 3 to 10%, preferably 5 to 10%, and the cured resin obtained by curing under the same conditions has a flexural modulus of 3.7. ~ 5GPa, preferably 3.9 ~ 5G
It has characteristics such as Pa.

The reinforcing fibers used in the present invention include:
Glass fiber, carbon fiber, graphite fiber, aramid fiber, boron fiber, alumina fiber, silicon carbide fiber and the like are preferable.
These fibers may be used in combination of two or more,
In order to obtain a lighter and more durable molded product, it is preferable to use carbon fiber or graphite fiber.

In order to produce a lightweight and high-strength sporting goods such as golf shafts and fishing rods, carbon fibers having a higher elastic modulus among carbon fibers are used so that a small amount of material can exhibit sufficient product rigidity. Specifically, the tensile modulus is 200 to 800 GPa, preferably 220 to 800 GPa.
It is good to use the thing of a.

In the production of sports goods such as golf shafts, fishing rods, rackets and the like, the composite material according to the present invention is prepared, for example, by preparing a prepreg obtained by impregnating a reinforcing fiber with an epoxy resin composition, laminating the prepreg, and heat curing. And a method of fabricating it.

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

The prepreg according to the present invention is prepared by a wet method in which the matrix resin is dissolved in a solvent such as methyl ethyl ketone or methanol to reduce the viscosity and is impregnated, or a hot melt method in which the viscosity is reduced by heating and impregnated (dry method). can do.

The wet method is a method in which a reinforcing fiber is immersed in a solution of an epoxy resin composition, then pulled up, and the solvent is evaporated using an oven or the like. The hot melt method is a method in which the viscosity of the epoxy resin composition is reduced by heating. A method of impregnating directly into the reinforcing fibers, or once a film coated with an epoxy resin composition on release paper, etc.
Then, the film is stacked on both sides or one side of the reinforcing fiber and heated and pressed to impregnate the reinforcing fiber with a resin. The hot melt method is preferable because there is substantially no solvent remaining in the prepreg.

After laminating the obtained prepregs, a method of heating and curing the resin while applying pressure to the laminate, for example, is used.
A composite according to the invention is made.

The method for applying heat and pressure includes press molding, autoclave molding, bagging, wrapping tape, internal pressure molding, and the like. A molding method can be preferably employed.

The wrapping tape method is a method in which a prepreg is wound on a core metal such as a mandrel to obtain a cylindrical molded body, and is suitable for producing a rod-shaped body such as a golf shaft or 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 apply pressure. At the same time, the mold is heated and molded. It is suitably used when molding a complicated shape such as a golf shaft, a bat, tennis or a badminton racket.

The composite material according to the present invention can be obtained by directly impregnating a reinforcing fiber with an epoxy resin composition without using a prepreg, followed by heating and curing, for example, a hand lay-up method, a filament winding method, a pultrusion method. It can also be produced by a molding method such as a resin injection molding method and a resin transfer molding method. In these methods, it is preferable to prepare a resin composition by mixing two liquids of a main agent composed of an epoxy resin and a curing agent immediately before use.

[0083]

The present invention will be described in more detail with reference to the following examples. The measurement of the tensile elongation and the flexural modulus of the cured resin, the preparation of the prepreg, the preparation of the composite material, and the measurement of the 0 ° compression strength and the 90 ° tensile elongation were performed under the following conditions. A. Tensile elongation of the cured resin The resin composition is 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 SK7113, a small 1 (1/2) type test piece was cut out and the tensile elongation was determined. B. Flexural Modulus of Cured Resin The resin composition is 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, a test piece having a width of 10 mm and a length of 60 mm was cut out from the cured resin sheet, and three-point bending with a span of 32 mm was measured. The flexural 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 weight fraction of 24% was prepared. D. Preparation of Composite Material A predetermined number of unidirectional prepregs were laminated so that the direction of the reinforcing fiber was the same, and then molded at 0.29 MPa at 135 ° C. for 2 hours using an autoclave to obtain a plate-shaped composite material. E. FIG. 0 degree compressive strength of composite material From a plate-shaped composite material obtained by laminating 11 unidirectional prepregs, according to ASTM D695, a width of 12.7 mm,
A test piece having a length of 79.4 mm was prepared, and the compressive strength was measured. F. 90 degree tensile elongation of the composite material From a plate-shaped body of the composite material obtained by laminating 21 unidirectional prepregs, a width of 25.4 m according to ASTM D3039.
A test piece having a length of m and a length of 38.1 mm was prepared and subjected to a tensile test to determine the elongation. (Examples 1 to 7) As shown in Table 1, general formulas (I), (II), or
The epoxy resin represented by (III) and the epoxy resin represented by the general formula (IV) were mixed and kneaded with a kneader to prepare a resin composition.

Further, a plate of a cured resin was prepared from the resin composition by the method described above, and its tensile elongation and flexural modulus were measured.

As shown in Table 1, all of them exhibited high values of elastic modulus and tensile elongation. Next, a unidirectional prepreg was prepared using the resin composition by the method described above,
These were laminated and cured to produce a composite material, and the 0 ° compression strength and 90 ° tensile elongation were measured.

As shown in Table 1, each of the examples showed high values of 0 ° compression strength and 90 ° tensile elongation. Comparative Example 1 The resins shown in Table 1 were mixed and kneaded with a kneader to prepare a resin composition.

As shown in Table 1, the elastic modulus and tensile elongation exhibited lower values. Next, a unidirectional prepreg was prepared using the resin composition by the above-described method, laminated and cured to prepare a composite material, and the 0 ° compression strength and the 90 ° tensile elongation were measured.

As shown in Table 1, in this example, the 0 ° compressive strength and the 90 ° tensile elongation exhibited lower values.

[0089]

[Table 1]

[0090]

According to the present invention, an epoxy resin composition having excellent elastic modulus and tensile elongation of a cured resin, a prepreg using the same, and further comprising the epoxy resin composition and a reinforcing fiber. , A composite material having excellent 0-degree compression strength and 90-degree tensile elongation can be provided, and such a composite material can be preferably applied to an extremely wide range of uses such as sports use, aerospace use, and general industrial use.

Continued on the front page (72) Inventor Shunsaku Noda 1515 Tsutsui, Matsumaemachi, Matsue-machi, Iyo-gun, Ehime F-term in the Ehime Plant of Toray Industries, Inc. AL05 4J036 AD01 AD08 AG01 AG07 AH01 CB20 DB06 DB15 DC06 DC10 DC30 DC31 DC35 FA14 FB07 FB15 JA11 JA15

Claims (4)

[Claims] An epoxy resin composition comprising the following components [A] and [B] and a curing agent. [A]: an epoxy resin having an oxazolidone ring and two epoxy groups in the molecule [B]: an epoxy resin represented by the following general formula (I), (II) or (III) (Wherein, R ^{1 to} R ⁴ each represent hydrogen, halogen,
A substituent selected from the group consisting of ８ to 8 alkyl groups. ) (Wherein, R ^{5 to} R ⁸ are each hydrogen, halogen,
A substituent selected from the group consisting of ８ to 8 alkyl groups. ) (In the formula, R ^{9 to} R ¹³ are each a substituent selected from hydrogen, halogen, and an alkyl group having 1 to 8 carbon atoms.) 2. The epoxy resin composition according to claim 1, wherein said component [A] is represented by the following general formula (IV). Embedded image (In the formula, n is an integer of 0 or more, and Y has 6 to 20 carbon atoms.
Wherein X is a substituent represented by the following formula. ) (Wherein, m is an integer of 0 or more, and Z is -CH _2- , -CH (C
H ₃ )-, a divalent substituent selected from -C (CH ₃ ) ₂ -and -SO _2- . ) 3. The amount of the bifunctional epoxy resin having two epoxy groups in the molecule is 100% by weight of the total epoxy resin.
The epoxy resin composition according to claim 1, wherein the content is 70 to 100% by weight based on the weight of the epoxy resin composition. 4. A prepreg obtained by impregnating reinforcing fibers with the epoxy resin composition according to claim 1.