JP2003103519A - Prepreg sheet, tubular article, and golf club shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tubular article made of a fiber-reinforced composite material which can be suitably used for a gold club shaft or the like and which has a high twist strength. SOLUTION: A prepreg sheet contains reinforcing fibers drawn and aligned in one direction and an epoxy resin composition in such a manner that the tensile elastic modulus E (GPa) of the fiber and a 6 deg.-compression strength σ(MPa) of the fiber-reinforced composite material satisfy formula (1): 200 GPa<=E<=950 GPa and formula (2): -3.6E+2,000<=σ<=-3.6E+2,600. The tubular article comprises a fiber-reinforced composite material layer obtained by thermosetting such a prepreg sheet. Further, a golf club shaft is made by using such a tubular article.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a prepreg sheet as an intermediate substrate for obtaining a fiber-reinforced composite material, and a tubular body made of the fiber-reinforced composite material. More specifically, the present invention relates to a tubular body that is lightweight and excellent in torsional strength, and is suitably used for a golf club shaft, a sports equipment such as a badminton racket, an aerospace structure, a truss, a mast, a ship, and a propeller shaft of an automobile.

[0002]

2. Description of the Related Art Fiber-reinforced composite materials composed of reinforcing fibers and matrix resins are widely used for sports applications, aerospace applications, and general industrial applications because of their excellent lightweight performance and mechanical properties.

In sports applications, fiber reinforced composite materials are formed into tubular bodies and used for golf club shafts, fishing rods, tennis and badminton rackets, and the like.

Golf club shafts, fishing rods, and the like are required to have lightweight performance, high material rigidity, and material strength.
Carbon fiber is used as the reinforcing fiber, and epoxy resin is used as the matrix resin.

In such a carbon fiber reinforced composite material, the tensile strength in the same direction as the fiber (0 degree tensile strength) is generally high because it reflects the high tensile strength of the carbon fiber, while the compressive strength in the same direction as the fiber (0 degree). Compressive strength) is generally low,
Studies have been conducted to improve this.

[0006] For example, Japanese Patent Laid-Open No. 2001-131833 discloses a method of improving the compressive strength of the carbon fiber itself in the fiber direction, but the manufacturing cost tends to be high and the obtained compressive strength is high. There were problems such as not being enough.

On the other hand, as an attempt to improve the 0 ° compression strength by improving the matrix resin, JP-A-11-1
A method for improving the flexural modulus of a matrix resin, such as disclosed in Japanese Patent Publication No. 71976, is known.
The effect of improving the 0 ° compression strength was recognized.

However, in the carbon fiber reinforced composite material used as an actual member, the compressive stress (hereinafter referred to as "non-existence") in the direction in which the angle with the fiber direction is not 0 degree but a constant angle of less than 90 degrees is formed. Described as compressive stress in the main axis direction)
Is often added. Even if it is considered that 0 ° compressive stress is applied in design, the fiber orientation may locally bend due to the shape of the member, and if compressive stress is applied to such a part, A compressive stress in the main axis direction will be applied. For example, a fiber-reinforced composite material tubular body used for a golf shaft often has a bias layer in which the direction of the reinforcing fibers is arranged at an angle of 25 to 65 degrees with respect to the main axis of the tubular body. When torsional stress is applied to the body, non-principal axis compressive stress is applied to the bias layer, which often causes breakage of the golf shaft.

In such a case, 0 as described above is used.
There is a case that the strength is insufficient only by improving the compressive strength.

Further, as the performance and quality of golf club shafts and fishing rods have become higher and higher in recent years, the performance required for the tubular body, which is the material thereof, is becoming more and more severe. In order to improve the lightweight performance of such a tubular body and to enhance the material rigidity and the material strength, Japanese Utility Model Laid-Open No. Sho 62-33872 and Japanese Unexamined Patent Publication No. 9-327536 disclose the outer circumference of a shaft composed of a bias layer and a straight layer. A method of providing a bias layer is disclosed.

[0011] However, according to this technique, the weight of the shaft is insufficiently dealt with, or the number of layers is increased,
There is a problem that the manufacturing process becomes complicated.

On the other hand, Japanese Unexamined Patent Publication (Kokai) No. 4-218179 discloses a technique of arranging reinforcing layers in order to increase torsional strength, and Japanese Unexamined Patent Publication (Kokai) No. 6-114131 discloses the direction of reinforcing fibers in each layer. There is disclosed a technique of stacking layers symmetrically with respect to each other.

However, according to these techniques, the weight of the tubular body is large, and the number of layers is increased to complicate the manufacturing process, resulting in a disadvantage in manufacturing cost.

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a fiber-reinforced composite material tubular body having high torsional strength, which can be suitably used for a golf club shaft or the like. is there.

[0015]

In order to achieve the above object, the present invention has the following constitution. That is, the 6-degree compressive strength of a fiber-reinforced composite material comprising reinforced fibers aligned in one direction and an epoxy resin composition and having a tensile elastic modulus E (GPa) of the reinforced fibers and being heat-cured. σ (MP
a) is a prepreg sheet characterized by satisfying the following expressions (1) and (2).

200 GPa ≦ E ≦ 950 GPa (1) −3.6E + 2000 ≦ σ ≦ −3.6E + 2600 (2) The present invention also has the following configuration. That is, it is a tubular body including a fiber-reinforced composite material layer obtained by heating and curing such a prepreg sheet, and a golf club shaft using the tubular body.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION In the prepreg sheet of the present invention, the tensile elastic modulus E (GPa) of the reinforcing fiber must satisfy the following expression (1).

200 GPa ≦ E ≦ 950 GPa (1) When it is less than 200 GPa, the tubular body does not have sufficient rigidity, and for example, when it is used as a golf club shaft, directional stability of the ball cannot be obtained. This is not preferable because it may cause such inconvenience. When it exceeds 950 GPa, the compressive strength of the reinforcing fiber becomes low and the torsional strength of the tubular body may be impaired. The tensile modulus E is calculated by the following equation (3)
Is more preferable, and it is more preferable that the formula (4) is satisfied.

200 GPa ≦ E ≦ 650 GPa (3) 350 GPa ≦ E ≦ 650 GPa (4) Further, in the present invention, the 6-degree compression strength σ of the fiber-reinforced composite material obtained by heat curing the prepreg sheet. (MPa)
However, it is necessary to satisfy the following expression (2).

-3.6E + 2000 ≦ σ ≦ −3.6E + 2600 (2) By setting the prepreg sheet in a specific range that satisfies the above formulas (1) and (2) at the same time, high rigidity is obtained. The present inventors have found that a fiber-reinforced composite material having improved mechanical strength can be obtained, and in particular, a member using a tubular body such as a golf shaft can be reduced in weight.

If σ is less than the value of −3.6E + 2000, the strength of the fiber-reinforced composite material obtained by heating and curing the prepreg sheet against the compressive stress in the non-main axis direction is insufficient, and the strength when the material is made lighter. Run out. Further, when σ exceeds the value of −3.6E + 2600, the matrix resin may become brittle and the impact resistance of the obtained fiber reinforced composite material may be rather deteriorated.

It is more preferable that σ satisfies the expression (5), and it is further preferable that the expression (6) is satisfied.

−3.6E + 2050 ≦ σ ≦ −3.6E + 2600 (5) −3.6E + 2070 ≦ σ ≦ −3.6E + 2600 (6) Fiber weight per unit area of the prepreg sheet of the present invention ( Hereinafter, the fiber unit weight is preferably 50 to 200.
g / m ^2, more preferably of good a 70~150g / m ^2. The fiber content of the prepreg sheet is preferably 65 to 87% by weight, more preferably 70 to 85% by weight. If the fiber areal weight is less than 50 g / m ² , the shape retention as a prepreg may be insufficient, and if it exceeds 200 g / m ² , impregnation of the reinforcing fibers with the resin may be insufficient. The fiber content is 65
If the amount is out of the range of from about 87% by weight, the effect of increasing the weight reduction and the formability of the tubular body may be impaired.

The prepreg sheet of the present invention comprises reinforcing fibers aligned in one direction. "Aligning in one direction" means that the longitudinal directions of the reinforcing fiber bundles are substantially the same.

As the reinforcing fibers in the prepreg sheet of the present invention, carbon fibers, glass fibers, aramid fibers, boron fibers, alumina fibers, silicon carbide fibers and the like can be used. Further, two or more kinds of these fibers can be mixed.
In order to obtain a lighter and more durable molded product, it is preferable to include carbon fibers having a tensile elastic modulus of 200 to 650 GPa.

If the tensile modulus of the reinforcing fiber is less than 200 GPa, the tubular body may not have sufficient rigidity, and if it exceeds 650 GPa, the compressive strength of the reinforcing fiber becomes low, and the torsional strength of the tubular body, etc. Strength may be impaired.

Examples of the reinforcing fiber used in the present invention include acrylic, pitch and rayon carbon fibers. Among them, acrylic carbon fiber having high tensile strength is preferable. As the form of carbon fiber, carbon fiber obtained by twisting and firing precursor fiber, so-called twisted yarn, untwisted carbon fiber of the twisted yarn, so-called untwisted yarn, substantially twisted precursor fiber Although untwisted yarns that are heat-treated without heat treatment can be used, untwisted yarns or untwisted yarns are preferable in consideration of the balance between the formability and strength characteristics of the fiber-reinforced composite material. Furthermore, handling such as adhesion between prepreg sheets Untwisted yarns are preferred from the viewpoint of properties. Further, the carbon fiber in the present invention may also include graphite fiber.

The carbon fiber of the present invention enhances the adhesiveness of the epoxy resin composition to the resin cured product and improves the strength characteristics of the fiber reinforced composite material against compressive stress in the non-main axis direction. It is preferable to attach a sizing agent having at least one functional group selected from an epoxy group, a hydroxyl group, an acrylate group, a methacrylate group, a carboxyl group and a carboxylic acid anhydride group. By attaching the sizing agent having these functional groups to the carbon fiber, a chemical bond or a non-covalent bond such as a hydrogen bond is formed between the functional group on the carbon fiber surface and the functional group in the polymer network of the cured resin. It is possible to cause an interaction and enhance the adhesiveness between the carbon fiber and the resin cured product.

Further, as such a sizing agent, in order to enhance the adhesion between the carbon fiber and the resin cured product, and when water is used as a solvent in the step of attaching the sizing agent to the carbon fiber, the handling thereof is easy. It is preferably water-soluble from the standpoint of becoming

As a method for producing the carbon fiber having the sizing agent attached thereto, for example, the carbon fiber is caused to pass through a sizing solution in which the sizing agent is dissolved or dispersed so as to be attached to the surface of the carbon fiber, and then heated. There is a method of removing the solvent, which can be preferably used.

Examples of compounds having an epoxy group that can be contained in the sizing agent of the present invention include bisphenol A type epoxy resins and hydrogenated products thereof, bisphenol F type epoxy resins and hydrogenated products thereof, and bisphenol S type epoxy resins. Resin, tetrabromobisphenol A type epoxy resin, bisphenol AD type epoxy resin, resorcinol diglycidyl ether, hydroquinone diglycidyl ether, 4,4′-dihydroxy-
3,3 ′, 5,5′-tetramethylbiphenyl diglycidyl ether, diglycidyl ether of 1,6-dihydroxynaphthalene, diglycidylaniline, diglycidylamine of o-toluidine, 9,9-bis (4-hydroxyphenyl) ) Diglycidyl ether of fluorene, isocyanate-modified epoxy resin having oxazolidone ring in the molecule, diglycidyl phthalate ester, diglycidyl terephthalate ester, diglycidyl ester hexahydrophthalate, diglycidyl ester hexahydroterephthalate, dimer acid dimer Glycidyl ester, 1,
4-di-tert-butyl-2,5-bis (2,3-epoxypropoxy) -benzene, 2,2'-dimethyl-
Reaction product of 4,4′-dihydroxy-5,5′-di-tert-butyldiphenyl sulfide and chloromethyloxirane, 4,4′-methylenebis (2,6-dimethylphenol) and chloromethyloxirane Reaction products, polyepoxides obtained by oxidizing a compound having two or more double bonds in the molecule, triglycidyl ether of tris (p-hydroxyphenyl) methane and its derivatives, tetrakis (p-hydroxyphenyl) ethane Tetraglycidyl ether and its derivatives, triglycidyl ether of glycerin, tetraglycidyl ether of pentaerythritol, glycidyl ether of novolak obtained from phenol derivatives such as phenol, alkylphenol and halogenated phenol, tetraglycidyl diamid Diphenylmethane, tetraglycidyl -m- xylylenediamine, triglycidyl -m
-Aminophenol, triglycidyl-p-aminophenol, triglycidyl isocyanurate and the like can be mentioned, and these can be used alone or in combination.

Examples of the compound having a hydroxyl group which can be contained in the sizing agent of the present invention include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol,
Dipropylene glycol, polypropylene glycol,
2-methyl-1,3-propanediol, 1,3-butanediol, neopentyl glycol, hydrogenated bisphenol A, 1,4-butanediol, bisphenol A
And propylene oxide or ethylene oxide adduct, 1,2,3,4-tetrahydroxybutane, glycerin, trimethylolpropane, sorbitol, 1,3
-Propanediol, 1,2-cyclohexane glycol, 1,3-cyclohexane glycol, 1,4-cyclohexane glycol, 1,4-cyclohexanedimethanol, paraxylene glycol, bicyclohexyl-
4,4'-diol, 2,6-decalin glycol,
Aliphatic alcohols such as 2,7-decalin glycol,
Glucose, sugars such as fructose and the like,
These can be used alone or in combination.

Examples of the compound having an acrylate group or a methacrylate group which can be contained in the sizing agent of the present invention include methyl (meth) acrylate, ethyl (meth) acrylate, t-butyl (meth) acrylate, N-Butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, (meth) ) Benzyl acrylate, stearyl (meth) acrylate, tridecyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, ethylene glycol monomethyl ether (meth) acrylate, ethylene glycol monoethyl ether (meth) acrylate,
Ethylene glycol monobutyl ether (meth) acrylate, ethylene glycol monohexyl ether (meth) acrylate, ethylene glycol mono-2-ethylhexyl ether (meth) acrylate, diethylene glycol monomethyl ether (meth) acrylate, diethylene glycol monoethyl ether (meth) acrylate, diethylene glycol mono Butyl ether (meth) acrylate, diethylene glycol monohexyl ether (meth) acrylate, diethylene glycol mono-2-ethylhexyl ether (meth) acrylate, dipropylene glycol monomethyl ether (meth) acrylate, dipropylene glycol monoethyl ether (meth) acrylate, dipropylene glycol Monobutyl ether (Meth) acrylate, dipropylene glycol monohexyl ether (meth) acrylate, dipropylene glycol mono-2-ethylhexyl ether (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, diethylene glycol di (meth) Acrylate, dipropylene glycol di (meth) acrylate, neopentyl glycol di (meth)
Acrylate, polytetramethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 2-hydroxy-1,3-di (meth) acryloxy Propane, 2,2-bis [4- (methacryloxyethoxy) phenyl] propane, 2,2-bis [4- (methacryloxydiethoxy) phenyl] propane, polyester (meth) acrylate, epoxy (meth) acrylate, urethane (Meth) acrylate and the like can be mentioned, and these can be used alone or in combination.

Examples of the compound having a carboxyl group or a carboxylic acid anhydride group that can be contained in the sizing agent of the present invention include dodecenylsuccinic acid, polyadipic acid, polyazelaic acid, polysebacic acid, phthalic acid,
Examples include methyltetrahydrophthalic acid, methylhexahydrophthalic acid, methylhymic acid, hexahydrophthalic acid, tetrahydrophthalic acid, trimellitic acid, pyromellitic acid, and acid anhydrides thereof, which may be used alone or in combination of two or more. be able to.

A sizing agent is attached to the carbon fiber used in the present invention in an amount of 0.1 to 2% by weight, preferably 0.5 to 1.5% by weight, more preferably 0.5 to 1.2% by weight. You can

When the amount of the sizing agent attached is more than 2% by weight, the spreadability of the single fiber during the preparation of the prepreg sheet becomes insufficient, and defects such as voids are formed in the prepreg sheet and by extension, in the fiber-reinforced composite material after molding. May occur, so that sufficient strength characteristics may not be exhibited.

On the other hand, if the amount of the sizing agent is less than 0.1% by weight, the effect of improving the adhesiveness may not be sufficient, or fluff may easily occur when handling the carbon fiber.

The epoxy resin composition used for the prepreg sheet of the present invention has a compressive elastic modulus of a resin cured product obtained by heating and curing the prepreg sheet, and in order to exhibit excellent material strength, it is 2.4 to 4.0 GPa. Is preferred,
2.7-3.5 GPa is more preferable and 2.8-3.3.
GPa is more preferred. Such compression elastic modulus is 2.4 G
If it is less than Pa, the yield strength against the compressive stress is insufficient and the material strength becomes insufficient, and if it exceeds 4.0 GPa, the cured resin product becomes brittle, or the residual thermal stress in the material becomes large, and so on. The impact resistance, tensile strength, etc. of the fiber-reinforced composite material to be used may decrease.

By using the resin compression elastic modulus as an index, the material strength characteristics in the compression mode can be controlled more accurately than the bending elastic modulus and the tensile elastic modulus.

Here, the compression elastic modulus of the resin cured product in the present invention is a test speed of 1 ± 0. 0 for a test piece cut out from the resin cured product so as to be a cube having a side length of 6 ± 0.2 mm. 2 mm / min, other conditions are JIS K71
It is measured based on 81.

Here, the compressive elastic modulus in the present invention is J
It is a value calculated by the following equation (7) based on IS K7181.

Ec = (σ2-σ1) / (ε2-ε1) (7) (where Ec is the compressive elastic modulus, σ1 and σ2 are measured at the compressive strains ε1 and ε2, respectively, and are calculated by the equation (8). The compressive stresses ε1 and ε2 are compression strains calculated by the equation (9), and ε1 = 0.05% and ε2 = 0.
25%. ) Σ = F / A (8) (where, σ represents compressive stress, F represents compressive load, and A represents the initial average cross-sectional area of the test piece) ε (%) = 100 × ΔL / L0 (9) ) (However, L0 is the distance between the first marked lines on the test piece, Δ
L represents the amount of decrease in the distance between the marked lines. ) The resin cured product used in the compression test is 100 to 200.
It is obtained by heat treatment for 90 minutes at a constant temperature selected from the range of ° C.

The epoxy resin composition used for the prepreg of the present invention comprises the following constituent elements (A) and (B).

The constituent element (A) of the present invention contains 2 in one molecule.
It is composed of an epoxy resin having one or more epoxy groups.

Specific examples of the epoxy resin having two epoxy resins in the molecule which can be used as the constituent element (A), that is, a bifunctional epoxy resin, include bisphenol A type epoxy resins obtained from bisphenol A and The hydrogenated product, bisphenol F type epoxy resin and its hydrogenated product, bisphenol S type epoxy resin obtained from bisphenol S, and bisphenol type epoxy resin such as tetrabromobisphenol A type epoxy resin obtained from tetrabromobisphenol A,
Bisphenol AD type epoxy resin obtained from bisphenol AD, resorcin diglycidyl ether, hydroquinone diglycidyl ether, 4,4′-dihydroxy-3,
3 ', 5,5'-Tetramethylbiphenyl diglycidyl ether, 1,6-dihydroxynaphthalene diglycidyl ether, aniline diglycidyl amine, o-toluidine diglycidyl amine, 9,9-bis (4-hydroxyphenyl) )
Diglycidyl ether of fluorene, isocyanate modified epoxy resin having oxazolidone ring in the molecule,
Phthalic acid diglycidyl ester, terephthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, hexahydroterephthalic acid diglycidyl ester, dimer acid diglycidyl ester, 1,4-di-tert-butyl-2,5-bis ( 2,3-epoxypropoxy) -benzene,
Reaction product of 2,2'-dimethyl-4,4'-dihydroxy-5,5'-di-tert-butyldiphenyl sulfide and chloromethyloxirane, 4,4'-methylenebis (2,6-dimethylphenol) And a chloromethyloxirane reaction product, a polyepoxide obtained by oxidizing a compound having two double bonds in the molecule, and the like, and these can be used alone or in combination.

Among these bifunctional epoxy resins, bisphenol F type epoxy resin, diglycidyl ether of 1,6-dihydroxynaphthalene, diglycidyl amine of aniline, and -From the group consisting of diglycidylamine of toluidine, isocyanate-modified epoxy resin having oxazolidone ring in the molecule, diglycidyl phthalate, diglycidyl terephthalate, diglycidyl hexahydrophthalate, diglycidyl hexahydroterephthalate At least one kind of epoxy resin selected is preferably contained in an amount of 10 to 100% by weight in 100% by weight of the constituent element (A), more preferably 20 to 100% by weight. If the compounding ratio is less than 10% by weight, the effect of improving the compression elastic modulus of the cured resin may not be sufficient.

Further, the constituent element (A) contains 2 parts in the molecule in order to improve the compression elastic modulus and heat resistance of the cured resin.
Polyfunctional epoxy resins having more than one epoxy group can be included.

The polyfunctional epoxy resin is not particularly limited, but triglycidyl ether of tris (p-hydroxyphenyl) methane and its derivative, tetrakis (p-
Hydroxyphenyl) ethane tetraglycidyl ether and its derivatives, glycerin triglycidyl ether, pentaerythritol tetraglycidyl ether, novolak glycidyl esters, tetraglycidyldiaminodiphenylmethane, tetraglycidyl esters obtained from phenol derivatives such as phenol and alkylphenols and halogenated phenols. Glycidyl m-xylylenediamine,
Triglycidyl-m-aminophenol, triglycidyl-
P-aminophenol, triglycidyl isocyanurate, etc. can be used.

These polyfunctional epoxy resins are preferably contained in 0 to 50% by weight, more preferably 0 to 30% by weight, and further preferably 5 to 20% by weight based on 100% by weight of the constituent element (A). it can. If the amount of the polyfunctional epoxy contained exceeds 50% by weight, the cured resin product may become brittle.

As the curing agent for the constituent (B) of the present invention, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, m-phenylenediamine, m- Aromatic amines having active hydrogen such as xylylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine,
Aliphatic amines having active hydrogen such as bis (aminomethyl) norbornane, bis (4-aminocyclohexyl) methane, and dimer acid ester of polyethyleneimine, epoxy compounds, acrylonitrile, phenol and formaldehyde in amines having these active hydrogens, Modified amines obtained by reacting compounds such as thiourea, dimethylaniline, dimethylbenzylamine, tertiary amines without active hydrogen such as 2,4,6-tris (dimethylaminomethyl) phenol and 1-substituted imidazole , Carboxylic acid anhydrides such as dicyandiamide, tetramethylguanidine, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic acid anhydride, adipic hydrazide and naphthalenedicarboxylic acid Use of polycarboxylic acid hydrazide such as dolazide, polyphenol compound such as novolac resin, polymercaptan such as ester of thioglycolic acid and polyol, Lewis acid complex such as boron trifluoride ethylamine complex, aromatic sulfonium salt, etc. You can

These curing agents may be combined with a suitable curing aid for enhancing the curing activity. A preferred example is dicyandiamide containing 3-phenyl-1,
1-dimethylurea, 3- (3,4-dichlorophenyl) -1,
1-dimethylurea (DCMU), 3- (3-chloro-4-
Examples of combining urea derivatives such as methylphenyl) -1,1-dimethylurea and 2,4-bis (3,3-dimethylureido) toluene as curing aids, carboxylic acid anhydrides and novolac resins with tertiary amines. Examples of the combination of the above as a curing aid, and the like can be used in the present invention.

In the epoxy resin composition of the present invention,
In addition to the components (A) and (B), other components such as low molecular weight organic compounds, oligomers, polymer compounds, organic or inorganic particles can be included.

The low molecular weight organic compound additive that can be incorporated into the epoxy resin composition of the present invention includes amide groups in the molecule,
Examples thereof include compounds having a hydrogen-bonding functional group such as a urethane group, an imide group, and a sulfonamide group, and a functional group that reacts with the epoxy resin of the component (A) or the curing agent of the component (B). By blending, it is possible to increase the compression elastic modulus without significantly impairing the toughness and plastic deformability of the cured resin.

Examples of such low molecular weight organic compounds include N
-Glycidyl phthalimide, acrylamide, N, N'-
Examples thereof include dimethylacrylamide and acryloylmorpholine.

The oligomer that can be blended in the epoxy resin composition of the present invention includes polyester polyurethane having a polyester skeleton and a polyurethane skeleton, urethane having a polyester skeleton and a polyurethane skeleton, and a urethane (meth) acrylate group at the terminal of the molecular chain ( Examples thereof include (meth) acrylates and indene-based oligomers. Here, in the polyester polyurethane, when the epoxy resin composition is cured, the ester group in the molecular chain thereof reacts with the curing agent of the constituent element (B), particularly the curing agent having active hydrogen such as amino group. .

A thermoplastic resin is preferably used as the polymer compound that can be incorporated into the epoxy resin composition of the present invention. By blending the thermoplastic resin, the effect of controlling the viscosity of the resin, controlling the handleability of the prepreg sheet, or improving the adhesiveness is enhanced, which is preferable.

Examples of thermoplastic resins that can be preferably used in the present invention include polyvinyl acetal resins such as polyvinyl formal and polyvinyl butyral, polyvinyl alcohol, phenoxy resin, and thermoplastic resins having an amide bond, such as polyamide and polyimide. Examples of the thermoplastic resin having a sulfonyl group 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.

When the thermoplastic resin is contained, the thermoplastic resin is contained in an amount of 1 to 2 with respect to 100 parts by weight of the epoxy resin composition.
It is preferable to contain 0 part by weight from the viewpoint that the epoxy resin composition is provided with appropriate viscoelasticity and good physical properties of the composite material are obtained.

Regarding the viscoelasticity of the uncured epoxy resin composition used for the prepreg sheet of the present invention, which comprises the constituents (A) and (B) and, if necessary, other components, the prepreg can be handled well. In order to obtain the property, the storage elastic modulus G'at a measurement frequency of 0.5 Hz and 50 ° C is 300.
It is preferable to be ˜50,000 Pa. G'is 300
If it is less than Pa, the adhesive strength between the surfaces of the prepreg (hereinafter referred to as the adhesive strength of the prepreg) is weak, and in the prepreg laminating step, the laminated prepregs may be easily peeled off to hinder the laminating work. is there. Further, when G'exceeds 50000 Pa, the flexibility of the prepreg may be deteriorated, the shapeability on the curved surface may not be sufficient, and the impregnating property into the reinforcing fiber may be deteriorated.
Such viscoelasticity is achieved by optimizing the type and mixing ratio of the epoxy resin component contained in the constituent element (A), or by adding an appropriate amount of the thermoplastic resin.

Here, the storage elastic modulus G'at a measuring frequency of 0.5 Hz and 50 ° C. is measured by a viscoelasticity measuring device at a constant interval while increasing the temperature at a constant rate. It can be determined by the method of As an example of temperature-viscosity measurement using a viscoelasticity measuring device, Rheometric Scientific F.E., viscoelasticity measuring device Model No .: ARES, two pieces at a constant interval of 0.2 to 1.5 mm Place the sample on the parallel plates of the
℃, 1.5 ℃ / min temperature increase, measurement frequency 0.5Hz, data acquisition interval 15 seconds measured, sample temperature 50 ± 0.3 ℃
A method in which the storage modulus G ′ at 50 ° C. is used as the measured value at 50 ° C.

The prepreg of the present invention is produced, for example, by a method such as a wet method in which a resin composition is dissolved in a solvent such as methyl ethyl ketone or methanol to have a low viscosity and impregnated, or a hot melt method in which a resin composition is reduced in viscosity by heating and impregnated. can do.

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

In the hot-melt method, the reinforcing fiber is directly impregnated with the resin composition whose viscosity has been lowered by heating, or a film in which the resin composition is once coated on release paper is first prepared, and then the reinforcing fiber is prepared. A resin-impregnated prepreg can be produced by stacking the films from both sides or one side and applying heat and pressure.
The hot melt method is preferable because there is no solvent remaining in the prepreg.

Further, in the method of manufacturing a prepreg,
In the step of impregnating the reinforcing fibers with the resin, the maximum temperature reached by the resin composition needs to be in the range of 70 ° C to 150 ° C, and more preferably 80 to 130 ° C. When the maximum temperature exceeds 150 ° C, the reaction between the constituent elements (A) and (B) partially proceeds in the resin composition, which may impair the handleability as a prepreg, and is less than 70 ° C. If so, sufficient impregnation may be difficult.

The tubular body of the present invention is obtained by laminating a plurality of prepreg sheets and heat-curing the prepreg sheets. The prepreg sheets are cut into a predetermined shape and wound around a cored bar (mandrel). It can be manufactured by a sheet winding method in which a wrapping tape is wrapped, molded in a curing oven or the like, and then decoreed to remove the wrapping tape.

Here, in the method of applying heat and pressure,
A press molding method, an autoclave molding method, a bagging molding method, an internal pressure molding method or the like can be used.

In this internal pressure molding method, a preform in which a prepreg is wound around an internal pressure imparting body such as a thermoplastic resin tube is set in a mold, and then high pressure gas is introduced into the internal pressure imparting body to apply pressure. At the same time, this is a method of heating and molding the die. It is preferably used when molding a complicated shape object such as a golf club shaft, a baseball bat, or a racket such as tennis or badminton.

The tubular body of the present invention has a bias layer in which the direction of the reinforcing fibers is arranged at an angle of 25 to 65 degrees with respect to the main axis of the tubular body in order to provide appropriate bending and torsional rigidity at the same time, and the bias layer of the bias layer. It is preferable to include a straight layer that is laminated on the outer peripheral side and has a reinforcing fiber direction arranged at an angle of 0 to 20 degrees with respect to the main axis of the tubular body.

The bias layer in the tubular body of the present invention needs to be arranged at an angle of 25 to 65 degrees with respect to the main axis of the tubular body, preferably 35 to 5 degrees.
It should be 5 degrees. If it deviates from the angle range of 25 to 65 degrees, the torsional strength may be impaired.

Further, a bias layer having a two-layer structure in which the directions of the reinforcing fibers are axially symmetrical with respect to the main axis of the tubular body may be provided.

The fiber volume content of the bias layer is 55-80.
% Is preferable, and 65 to 75% is more preferable. here,
The fiber volume content Vf (volume%) is the fiber weight content Wf.
(% By weight), the density ρf (g / cm ³ ) of the reinforcing fiber, and the density ρc (g / cm ³ ) of the composite material are calculated by the following formula (10).

Vf = Wf × ρc / ρf (10) The fiber weight content Wf is determined by measuring the amount of fiber by burning and removing the resin cured product (matrix resin) in the fiber reinforced composite material with a burner flame or the like. It can be determined by a combustion method or a sulfuric acid decomposition method in which the resin amount is removed with hot concentrated sulfuric acid and the amount of fiber is measured.

Void content of the bias layer Vv
From the viewpoint of maintaining the torsional strength, (volume%) is preferably less than 5 volume%, more preferably less than 3 volume%, and further preferably less than 1 volume%.

Here, the void content Vv (volume%) is calculated from the following equation from the volume content Vr (volume%) of the matrix resin, Vf, and the resin density ρr.

Vr = (100−Wf) × ρc / ρr (11) Vv = 100− (Vf + Vr) (12) The thickness of each bias layer is 0.01 to 0.2.
mm is preferable, and 0.02-0.15 mm is more preferable. The bias layer preferably has 2 to 10 layers, and more preferably 4 to 8 layers.

In the tubular body of the present invention, the straight layer is required to be arranged at an angle of 0 to 20 degrees with respect to the main axis of the tubular body, preferably 0 to 20 degrees.
It should be 10 degrees. If it deviates from the range of 0 to 20 degrees, the strength against bending stress may be insufficient.

The fiber basis weight of the straight layer is preferably 5
0 to 200 g / m ² , more preferably 70 to 150 g /
It should be m ² . The fiber content of the straight layer is preferably 65 to 87% by weight, more preferably 70% by weight.
~ 85 wt% is good. Fiber weight is 50-200
Outside the range of g / m ² , the fiber content is 65 to 87% by weight
Outside of this range, the effect of increasing the weight and the formability of the tubular body may be impaired, which is not preferable.

The void content of the straight layer is preferably less than 5% by volume, more preferably less than 3% by volume, and even more preferably from the viewpoint of increasing the proof stress against bending, impact and crushing forces applied to the tubular body. It is preferably less than 1% by volume.

The thickness per straight layer is preferably 0.01 to 0.15 mm, and 0.02 to 0.1
mm is more preferable. Moreover, such a straight layer is 2 to 8
It is preferably a layer and more preferably 3 to 6 layers.

In the tubular body of the present invention, at least one straight layer needs to be arranged on the outer peripheral side of the bias layer. If the straight layer is arranged only on the inner peripheral side of the bias layer, the torsional strength of the tubular body may be greatly impaired.

In the present invention, the present inventors consider the reason why the laminated structure constituting the tubular body can effectively enhance the torsional strength of the tubular body as follows. When the tubular body is loaded with a twisting force, the bias layer mainly bears the load, but the present inventor has found that the winding end portion of the prepreg sheet of the bias layer has a portion where the reinforcing fiber locally bends. Found out. When a tubular body is loaded with a twisting force, the bent part of this reinforcing fiber may be the starting point of fracture, so if the strength against compressive stress in the non-main axis direction becomes higher, the torsional strength will be effectively increased. It is estimated that

In the tubular body according to the present invention, the tubular body can be provided with various performances by arranging a layer containing reinforcing fibers in various directions in addition to the above-mentioned bias layer and straight layer. For example, in order to provide a crush resistance against a crushing force (crushing force) from the side, a hoop layer in which the reinforcing fiber direction is arranged at an angle of 75 to 90 degrees with respect to the main axis of the tubular body, for example, It can be disposed between the bias layer and the straight layer or in the innermost layer.

The inner diameter of the tubular body can be appropriately selected depending on its use, but when it is used for a golf shaft, for example, it can be an inner diameter of about 3 to 15 mm. Further, the tubular body may have a straight shape in which the inner diameter is substantially uniform in the longitudinal direction of the tubular body, or may be tapered. Taper rate is 5 / 1000-1
2/1000 is preferred.

When the tubular body according to the present invention is applied to a golf club shaft, torsional fracture of the shaft often occurs in a region up to 500 mm in the longitudinal direction from the tip end on the head side. By arranging the layers, various performances can be exhibited in the tubular body. The reinforcing layer here is preferably arranged such that the direction of the reinforcing fibers with respect to the main axis of the tubular body is 0 to 65 degrees, more preferably 0 to 50 degrees.

When the tubular body according to the present invention is used for a golf club shaft, the total weight of the golf club shaft is preferably 20 to 65 g, more preferably 20 to 5 g.
Even with a lightweight product of 0 g, the torsional strength can be sufficiently exhibited. Further, the golf club shaft according to the present invention has an SG twist strength of 800 to 3000 N · m ·.
When the degree and torque are 2 to 7 degrees and the flex is 40 to 90 mm, the physical properties such as light weight performance and bending stress resistance and torsional strength are balanced, which is preferable. When the total weight of the golf shaft is less than 20 g, the golf shaft has
Sufficient SG torsional strength, torque, and flex may not be obtained, which may increase the possibility of shaft breakage. On the other hand, if the total weight of the golf shaft exceeds 65 g, the balance control of the physical properties of the SG torsional strength, torque, and flex becomes easy, but the weight is bulky and the lightweight performance may be impaired.

[0086]

EXAMPLES The present invention will be described in detail below with reference to examples. Each physical property value was measured by the following methods. In addition, unless otherwise specified, the physical properties are measured at a temperature of 23 ± 2 ° C. and a relative humidity of 50.
It was performed under ± 10%. <Tensile Elastic Modulus of Reinforcing Fiber> Measured according to JIS-R-7601.

An alicyclic epoxy resin (ERL4221, Union Carbide Japan Co., Ltd.) / Boron trifluoride / monoethanolamine complex (100 parts by weight / 3 parts by weight) as an impregnating resin was used as a test piece in an organic solvent solution. It was obtained by impregnating the strands with and curing by heating (130 ° C., 35 minutes).

The measurement was carried out using a strand tensile tester (constant speed tension type tensile tester) with a test length of 200 mm and a pulling speed of 60.
It was measured under the condition of mm / min. <Compression test of cured resin> The resin composition is heated to 80 ° C, defoamed with a vacuum pump, and then poured into a mold to obtain 130 ° C.
By heat-treating for 90 minutes, a plate of 6 mm-thick resin cured product was prepared. Then, a cubic test piece having a side length of 6 mm was cut out from the cured resin plate to give a test piece.

The test speed was 1 ± 0.2 mm / min, and the compression elastic modulus was measured under the other conditions based on JIS K7181. <Preparation of Composite Material, 6 Degree Compressive Strength> The unidirectional prepreg sheets were laminated so that the fiber directions were in the same direction, and the laminated plate had a thickness of approximately 1 mm, and the temperature was set to 130 ° C. in an autoclave. ℃, pressure 290P
A pressure was applied for 2 hours for heating and curing at a to prepare a unidirectional composite material. The obtained unidirectional composite material was cut out so that the angle of the reinforcing fibers with respect to the long side of the test piece was 6 degrees, and JIS-
It was measured according to the K-7076 method.

Thickness of unidirectional material, fiber areal weight, fiber density,
The fiber volume content (Vf) was calculated from the number of laminated plies, and the obtained 6-degree compressive strength was converted into a value of the volume content of the reinforcing fiber of 60%. <Torsion Strength of Composite Material Tubular Body and Shaft> Inner Diameter 10
A 400 mm long test piece is cut out from the mm tubular body,
"Golf Club Shaft Certification Criteria and Criteria Confirmation Method"
(Edited by the Product Safety Association, approved by the Minister of International Trade and Industry 5 Production No. 2087
No., 1993), and a torsion test was conducted. The gauge length of the test piece shall be 300 mm, and 5 at both ends of the test piece.
0 mm was gripped by a fixing jig.

In addition, the length of the golf club shaft is 1
Both ends of a 163 mm shaft were cut off by 10 mm to make a shaft of 1143 mm (45 inches), and then the weight was measured, and a test was conducted in the same manner as the measurement of the tubular body. The gauge length of the test piece was 1063 mm, and 50 mm at both ends of the test piece was held by a fixing jig. After that, the SG torsional strength was calculated by the following formula. SG Torsional strength (N ・ m ・ degree) = breaking torque (N ・ m) × twist angle (degree) at breaking <Shaft torque> Both ends of a golf club shaft with a length of 1163 mm were cut off by 10 mm, 1143 m
After making a shaft of m (45 inches), both ends of the shaft were fixed by a jig of 50 mm in the same manner as the measurement of the torsional strength of the shaft, and a test piece having a gauge length of 1063 mm was produced. Grasping the jigs on both ends of the shaft, 1.35N ・ m
The torque was the twist angle when a torque of (1 ftf · lb) was applied. <Flex of shaft> Cut both ends of a golf club shaft with a length of 1163 mm by 10 mm,
When a 3mm (45 inch) shaft is used, and a 2.7 kg weight is hung at a portion 175 mm from the small diameter tip of the shaft with two points 925 mm and 1065 mm from the small diameter tip of the shaft as fulcrums. The flexure was measured by measuring the amount of deflection of the 200 mm portion from the small diameter tip of the shaft. <Preparation of Epoxy Resin Composition> Epoxy resin compositions a, b, c and d were adjusted at the compounding ratios shown in Table 1. With respect to the obtained resin composition, the compression elastic modulus of the resin cured product was measured by the procedure described above. The results are summarized in Table 1.

The following resin raw materials were used for resin preparation. [Component A] "Epicoat" (registered trademark) 807: Bisphenol F type epoxy resin (manufactured by Japan Epoxy Resins Co., Ltd.) "Epicoat" 1004: Bisphenol A type epoxy resin (manufactured by Japan Epoxy Resins Co., Ltd.) AER4152: Molecule Isocyanate-modified epoxy resin having an oxazolidone ring inside (manufactured by Asahi Kasei Epoxy Co., Ltd.) GAN: diglycidylaniline (manufactured by Nippon Kayaku Co., Ltd.) [Component B] DICY7: dicyandiamide (manufactured by Japan Epoxy Resins Co., Ltd.) DCMU99: 3- (3,4-dichlorophenyl) -1,1-dimethylurea (manufactured by Hodogaya Chemical Co., Ltd.) [Others] ACMO: Acryloylmorpholine (manufactured by Kojin Co., Ltd.) "Vinilec" (registered trademark) K: Polyvinyl formal (manufactured by Chisso Corporation) "BOLTOR "(R) E1: epoxy group-containing dendrimer (Perstorp AB Corporation) was <prepreg Preparation of Sheet> epoxy resin composition was coated on a release paper using a reverse roll coater to prepare a resin film. Next, two resin films are superposed from both sides of the carbon fibers on the carbon fibers arranged in one direction in a sheet shape, sandwiched between metal rolls heated to 100 ° C., heat-pressed to impregnate the resin composition, and prepreg. Got the sheet.

As the carbon fibers of the prepreg sheets applied to the bias layers in the examples and the comparative examples, t1 to t4 to which polyethylene glycol diglycidyl ether was attached in the amount shown in Table 2 as a sizing agent were used.

As the carbon fiber of the prepreg sheet applied to the straight layer in Examples and Comparative Examples, T700SC-manufactured by Toray Industries, Inc. having a tensile modulus of 230 GPa, a fineness of 0.80 g / m and a filament number of 12000.
12K-50C (hereinafter referred to as t5), or a carbon fiber (hereinafter referred to as t6) having a tensile elastic modulus of 295 GPa, a fineness of 0.445 g / m, and a filament number of 12000 was used.

The resin compositions, reinforcing fibers, fiber areal weights and fiber contents used in the preparation of prepregs in Examples and Comparative Examples are as follows.
It is summarized in Table 3. (Example 1) Carbon fiber t1 (tensile elastic modulus: 375GP
Using a) and the epoxy resin composition a, a prepreg sheet A (fiber areal weight: 116 g / m ² , fiber content: 76% by weight) was obtained by the method described above.

The 6 degree compressive strength of the fiber reinforced composite material obtained by heating and curing the obtained prepreg sheet A was 796 GPa, and the prepreg sheet A satisfied the formulas (1) and (2) at the same time. did.

Next, by the following operation, a laminated structure of [0 ₃ / ± 45 ₃ ] was formed on the main axis of the tubular body, and the inner diameter was 10
mm tubular bodies were made. A round bar made of stainless steel having a diameter of 10 mm and a length of 1000 mm was used as the cored bar (mandrel).

As bias layers, two sheets were cut out from the prepreg sheet A into a rectangle having a length of 800 mm and a width of 103 mm (so that the fiber direction was 45 degrees with respect to the length direction). The two sheets were laminated so that the fiber directions intersect with each other and shifted in the lateral direction by 16 mm (corresponding to the length of a half circumference of the mandrel).

Next, the pasted prepreg sheet is
The mandrel subjected to the mold release treatment was wound so that the longitudinal direction of the prepreg in which the two prepreg sheets were attached and the main axis of the mandrel were aligned.

Furthermore, a prepreg sheet S1 in which the epoxy resin composition shown in Table 3 and carbon fiber was combined as a straight layer was cut into a rectangle of 800 mm length × 112 mm width so that the fiber direction was the vertical direction. ,
The prepreg sheet was wound so that the longitudinal direction and the axial direction of the mandrel were aligned.

Next, a wrapping tape (heat shrinkable film tape) for sheet wind molding was wound by a predetermined method, and then heat molded in a curing oven at a temperature of 130 ° C. for 2 hours.

Thereafter, the mandrel is decoreed (removed).
Then, the wrapping tape was removed to obtain a tubular body.

When the torsional strength of the obtained tubular body was measured, it showed good values as shown in the table. (Examples 2 to 4) Prepreg sheet B, in the same manner as in Example 1 except that epoxy resin compositions b, c and d were used.
C and D were produced. The obtained prepreg sheets B, C,
The compressive strength of D was measured at 6 degrees by the above-mentioned method, and as shown in Table 4, the expressions (1) and (2) were simultaneously satisfied.

Next, the prepreg sheet B,
A tubular body was molded in the same manner as in Example 1 except that C and D were used respectively. When the torsional strength was measured, a good value was shown. (Comparative Example 1) A prepreg sheet E was produced in the same manner as the prepreg sheet C of Example 3 except that the carbon fiber t2 was used. When the prepreg E was measured for compressive strength at 6 degrees by the above-mentioned method, the value was low, and the formula (2) was not satisfied.

A tubular body was formed in the same manner as in Example 1 except that the prepreg sheet E was used as the bias layer. When the torsional strength of such a tubular body was measured, the value was at a low level. (Example 5) A prepreg sheet F was obtained in the same manner as in the prepreg sheet C of Example 3 except that the fiber areal weight was 125 g / m ² . When the prepreg sheet F was measured for compressive strength at 6 degrees by the above-mentioned method, the formulas (1) and (2) were satisfied.

The prepreg sheet F is used as the bias layer,
A tubular body was molded in the same manner as in Example 1 except that the prepreg sheet S2 shown in Table 3 was used as the straight layer. When the torsional strength was measured, a good value was shown. (Comparative Example 2) A prepreg sheet G was obtained in the same manner as in the prepreg sheet F of Example 5 except that the carbon fiber t2 was used. When the compressive strength of the prepreg sheet G was measured at 6 degrees, the value was low, and the formula (2) was not satisfied.

A tubular body was molded in the same manner as in Example 1 except that the prepreg sheet G was used as the bias layer and the prepreg sheet S2 was used as the straight layer, and the torsional strength thereof was measured. It was strong. (Example 6) A prepreg sheet H was produced in the same manner as the prepreg sheet F of Example 5 except that the carbon fiber t3 was used. 6 for the prepreg sheet H by the above-mentioned method
When the compressive strength was measured, the formulas (1) and (2) were satisfied.

The prepreg sheet H is used as the bias layer,
A tubular body was formed in the same manner as in Example 1 except that the prepreg S2 was used as the straight layer, and the torsional strength thereof was measured, and a good value was shown. (Comparative Example 3) Carbon fiber t4 (tensile modulus: 475 GP
A prepreg sheet I was produced in the same manner as in the prepreg sheet F of Example 5 except that a) was used. When the prepreg sheet I was measured for compressive strength at 6 degrees by the above-mentioned method, the value was low, and the formula (2) was not satisfied.

A tubular body was formed in the same manner as in Example 1 except that the prepreg sheet I was used as the bias layer and the prepreg sheet S2 was used as the straight layer. When the torsional strength was measured, it showed a low value. (Example 7) As bias layers, two unidirectional prepreg sheets C were cut into a trapezoid of 1163 mm in length x 151 mm in length (long side 151 mm, short side 63 mm) so that the direction of the fibers was 40 degrees with respect to the longitudinal direction. The two pieces are bonded so that the fiber directions intersect each other and laterally offset by half the entire length of the mandrel. This is a small diameter tip outer diameter 4.4 mm, taper rate 8/1000, length 1500 mm, mold release The prepreg sheet was wound around the treated stainless mandrel so that the longitudinal direction of the prepreg sheet and the main axis of the mandrel coincided with each other so that the lateral short side of the prepreg sheet was in the tip direction of the mandrel.

On top of that, a prepreg sheet S2 is formed as a straight layer in a longitudinal direction 116 so that the fiber direction is the longitudinal direction.
A trapezoid having a size of 3 mm × width (long side 160 mm, short side 72 mm) was cut and wound so that the horizontal short side of the prepreg sheet was in the tip direction of the mandrel so that the longitudinal direction of the prepreg sheet and the mandrel main axis were aligned.

Further, a prepreg sheet S2 for reinforcing layer was cut into a right-angled triangle having a length of 230 mm and a width of 128 mm, and a horizontal side of the prepreg sheet had a mandrel so that the longitudinal direction of the prepreg sheet was aligned with the mandrel main axis. It was wrapped so that it was in the tip direction.

Next, after wrapping a wrapping tape for sheet wind molding by a predetermined method, the temperature was set to 13 in a curing oven.
Molded by heating at 0 ° C. for 2 hours.

After molding, the mandrel was decoreed and the wrapping tape was removed to obtain a golf club shaft. (Comparative Example 4) A golf club shaft was obtained in the same manner as in Example 7 except that the unidirectional prepreg sheet E was used as the bias layer.

The torsional strengths of the tubular bodies obtained in Examples 1 to 6 and Comparative Examples 1 to 3 and the 6-degree compressive strength σ of the composite materials obtained by heating and curing the prepreg sheet used for the bias layer.
The measurement results of (MPa) are shown in Table 4, and the measurement results obtained in Example 7 and Comparative Example 4 are shown in Table 5.

[0115]

[Table 1]

[0116]

[Table 2]

[0117]

[Table 3]

[0118]

[Table 4]

[0119]

[Table 5]

[0120]

According to the present invention, it is possible to provide a tubular body made of a fiber-reinforced composite material having a high torsional strength, which can be suitably used for a golf club shaft or the like.

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) B29K 263: 00 B29L 31:52 B29L 31:52 B29C 67/14 C F term (reference) 2C002 AA05 CS03 MM02 PP01 4F072 AA04 AA07 AB10 AB22 AB25 AD23 AE01 AE02 AG03 AG12 AH19 AH21 AJ04 AK05 AK14 AL05 4F205 AA39 AD08 AD16 AG08 AH59 HA02 HA23 HA33 HA45 HB01 HC02 HK05 HL02 HL14

Claims (13)

[Claims] 1. A fiber-reinforced composite material comprising reinforced fibers aligned in one direction and an epoxy resin composition, having a tensile elastic modulus E (GPa) of the reinforced fibers, and a heat-curable composite material. A prepreg sheet having a 6-degree compressive strength σ (MPa) satisfying the following expressions (1) and (2). 200 GPa ≦ E ≦ 950 GPa (1) −3.6E + 2000 ≦ σ ≦ −3.6E + 2600 (2) 2. A prepreg sheet, wherein the 6-degree compressive strength σ (MPa) satisfies the following expression (3). −3.6E + 2050 ≦ σ ≦ −3.6E + 2600 (3) 3. The weight of the reinforcing fiber per unit area is 50 to 50.
200 g / m ² and fiber content of 65-87
The prepreg sheet according to claim 1 or 2, wherein the prepreg sheet has a weight percentage. 4. The reinforcing fiber is a carbon fiber having a tensile modulus of 200 to 650 GPa.
The prepreg sheet according to any one of 3 to 3. 5. An epoxy resin composition comprising the following constituent elements (A) and (B), wherein the cured resin of the cured resin has a compressive elastic modulus of 2.4 to 4 GPa. Item 5. The prepreg sheet according to any one of items 1 to 4. (A) Epoxy resin (B) Curing agent 6. A tubular body comprising a fiber-reinforced composite material layer obtained by heat-curing the prepreg sheet according to claim 1. 7. The reinforcing fiber direction is 25 to 25 with respect to the main axis of the tubular body.
A bias layer arranged at an angle of 65 degrees, and a straight layer laminated on the outer peripheral side of the bias layer and arranged at an angle of 0 to 20 degrees with respect to the main axis of the reinforcing fiber in the reinforcing fiber direction, and at least The tubular body according to claim 6, wherein the bias layer includes a fiber-reinforced composite material layer obtained by heat-curing the prepreg sheet according to any one of claims 1 to 4. 8. A golf club shaft comprising the tubular body made of the fiber-reinforced composite material according to claim 6 or 7. 9. A longitudinal direction of the head is 500 mm from the front end.
In the region up to 0, the direction of the reinforcing fiber is 0 with respect to the main axis of the tubular body
9. The golf club shaft according to claim 8, further comprising reinforcing layers arranged at an angle of about 65 degrees. 10. SG torsional strength is 800 to 3000 N.
The golf club shaft according to claim 8 or 9, wherein the golf club shaft has a m-degree. 11. The golf club shaft according to claim 8, wherein the total weight is 20 to 65 g. 12. The golf club shaft according to claim 8, wherein the torque is 2 to 7 degrees. 13. The golf club shaft according to claim 8, wherein the flex is 40 to 90 mm.