JP2003064199A - Prepreg and tubular body made of fiber-reinforced composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a prepreg for providing a tubular body made of a light- weight fiber-reinforced composite material having excellent strength characteristics such as torsional strength and rigidity, and further to provide the tubular body made of the fiber-reinforced composite material. SOLUTION: This prepreg comprises the following constitutional elements (A), (B) and (C) regulated so that the content of a bifunctional epoxy resin in 100 wt.% constitutional element (B) will be 75-100 wt.%: (A) a carbon fiber having 1.00-1.10 ratio of surface area measured by an interatomic force microscope, and 330 GPa-1,000 GPa tensile modulus; (B) the epoxy resin; (C) a curing agent. The tubular body made of the fiber-reinforced composite material includes a layer obtained by heating and hardening the prepreg.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a prepreg which is an intermediate base material for producing a fiber-reinforced composite material suitable for sports applications, aerospace applications, and general industrial applications, and fibers obtained by heat-curing the prepreg. The present invention relates to a tubular body made of a reinforced composite material.

[0002]

2. Description of the Related Art A fiber-reinforced composite material composed of carbon fiber and a matrix resin is widely used for sports applications, aerospace applications, and general industrial applications because of its excellent mechanical strength characteristics. Particularly in sports applications, shafts for golf clubs, fishing rods, rackets such as tennis and badminton, and sticks such as hockey can be mentioned as important applications.

Various methods are used for producing a fiber-reinforced composite material, and a method using a prepreg which is a sheet-shaped intermediate base material in which carbon fibers are impregnated with a matrix resin is widely used. In this method, a fiber-reinforced composite tubular body is obtained by laminating a plurality of prepregs and then heating them.

Fiber reinforced composite material tubular bodies for sports, that is, golf club shafts, fishing rods, and the like, are fields in which weight reduction is particularly required. When reducing the weight of a fiber-reinforced composite material, in order to make its rigidity appropriate,
It is effective to apply a reinforcing fiber having a high elastic modulus, but particularly when an attempt is made to apply a reinforcing fiber having a high elastic modulus such that the tensile elastic modulus is 330 GPa or more, the strength such as the torsional strength of the tubular body is increased. May run short.

In the past, Japanese Patent Laid-Open No. 2000-51411 has been used.
As disclosed in Japanese Patent Laid-Open Publication No. WO99 / 119407, International Publication No. WO00 / 44017, and the like, a method of improving the strength of a tubular body by applying an epoxy resin composition having a specific composition has been proposed. However,
Especially, in order to solve the lack of strength in the case of applying a reinforcing fiber having a high elastic modulus with a tensile elastic modulus of 330 GPa or more, the effect was not yet sufficient.

[0006]

The object of the present invention is to solve the problems of the prior art, to obtain a fiber reinforced composite material having excellent strength characteristics, and to further improve the handling property of the prepreg, and The present invention provides a tubular body made of a fiber-reinforced composite material obtained by using such a prepreg.

[0007]

In order to achieve the above object, the present invention has the following constitution. That is, the composition contains the following constituents (A), (B), and (C), and in 100% by weight of constituent (B), the difunctional epoxy resin is 75 to
This is a prepreg containing 100% by weight. (A) The surface area ratio measured by an atomic force microscope is 1.
00 to 1.10 and a tensile elastic modulus of 330 GPa
A carbon fiber (B) epoxy resin (C) curing agent of up to 1000 GPa, and a fiber-reinforced composite material tubular body including a layer formed by heating and curing the prepreg.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

Examples of the carbon fiber used as the constituent element (A) in the present invention include acrylic, pitch and rayon carbon fibers. Of these, acrylic resins having high tensile strength are preferable. As the form of the carbon fiber, twisted yarn, untwisted yarn, untwisted yarn, etc. can be used, but untwisted yarn or untwisted yarn is preferable in consideration of the balance between the moldability and strength characteristics of the composite material, and further the adhesion of the prepreg surfaces to each other. Untwisted yarns are preferable from the viewpoint of handleability such as property. Further, the carbon fiber in the present invention may also include graphite fiber.

As the carbon fiber in the present invention, a carbon fiber having a high tensile elastic modulus is used so that a sports article such as a golf club shaft or a fishing rod can exhibit sufficient rigidity by using a small amount of the material. The tensile modulus of elasticity of such a carbon fiber is 330 to 100.
It is necessary to be 0 GPa, and preferably 350 to 800 GPa. If the tensile modulus is less than 330 GPa, it is difficult to develop sufficient rigidity in the material, which is not preferable. If it exceeds 1000 GPa, the strength of the carbon fiber becomes insufficient, which is not preferable.

The carbon fiber as the constituent element (A) in the present invention is required to have a surface area ratio of 1.00 to 1.10 measured by an atomic force microscope by a method described later, and 1.00. It is more preferable if it is up to 1.05. The surface area ratio is the ratio of the actual surface area of the carbon fiber surface to the projected area and represents the degree of surface roughness. The closer the surface area ratio is to 1, the smoother the surface area is. Conventionally, when the carbon fiber is smooth, it has been considered that the adhesiveness between the matrix resin and the surface of the carbon fiber is reduced, and the strength of the resulting fiber-reinforced composite material is reduced, but as a result of intensive studies by the present inventors, In the case of a high elastic modulus type carbon fiber having a tensile elastic modulus of 330 GPa or more, it was surprisingly found that the smoother surface of the carbon fiber improves the strength of the tubular body made of the fiber reinforced composite material, and thus the present invention is realized. It has come. The surface area ratio is 1.00 when the carbon fiber surface has no irregularities,
If the surface area ratio exceeds 1.10, the effect of improving the strength of the tubular body is not sufficient, which is not preferable.

The acrylic carbon fiber that can be preferably used in the present invention can be manufactured, for example, through the steps described below.

A spinning dope containing polyacrylonitrile obtained from a monomer containing acrylonitrile as a main component is spun by a wet spinning method, a dry-wet spinning method, a dry spinning method, or a melt spinning method. The coagulated yarn after spinning is washed with water, drawn, dried, and subjected to a yarn-forming process such as application of an oil agent to produce an acrylic precursor, and the obtained acrylic precursor is subjected to flame resistance and carbonization to obtain an acrylic carbon fiber. be able to.

Here, as the spinning method, a wet spinning method or a dry wet spinning method can be preferably adopted, and a dry wet spinning method is more preferable because it is easy to obtain a carbon fiber having a smooth carbon fiber surface.

In the wet spinning method or the dry-wet spinning method, the surface roughness of the obtained carbon fiber can be controlled by appropriately optimizing the coagulation rate in the coagulation process after spinning and the draw ratio of the coagulated fiber. It is possible to do so, which is preferable.

Further, in the present invention, the component (A)
In addition to the carbon fiber, the reinforcing fiber such as glass fiber, aramid fiber, boron fiber, alumina fiber and silicon carbide fiber can be used in combination. Two or more kinds of these fibers may be mixed and used.

In the present invention, as the form of the carbon fibers, those in which the fiber directions are aligned in one direction and woven fabrics can be used. The woven fabric may be either plain weave or satin weave.

In order to reduce the weight of the fiber-reinforced composite material, the carbon fiber content in the prepreg is preferably high, and the carbon fiber content in the prepreg is preferably 70% by weight or more, more preferably 75%. It is preferable that the content is at least wt%, more preferably at least 80 wt%.

The epoxy resin of the constituent element (B) in the present invention is obtained by heat curing by adding 75 to 100% by weight of a bifunctional epoxy resin to 100% by weight of the constituent element (B). A resin cured product (hereinafter referred to as a resin cured product) exhibits sufficient tensile fracture elongation, toughness and plastic deformation ability, and imparts high strength characteristics to the fiber reinforced composite material combined with the above-mentioned constituent element (A). You can 7
If it is less than 5% by weight, the cured resin does not exhibit sufficient tensile breaking elongation, toughness and plastic deformation ability, which is not preferable.

Specific examples of the bifunctional epoxy resin include:
Bisphenol such as bisphenol A type epoxy resin obtained from bisphenol A, bisphenol F type epoxy resin obtained from bisphenol F, bisphenol S type epoxy resin obtained from bisphenol S, and tetrabromobisphenol A type epoxy resin obtained from tetrabromobisphenol A Type epoxy resin, resorcin diglycidyl ether, hydroquinone diglycidyl ether, 4,4'-dihydroxy-3,3 ', 5,5'-tetramethylbiphenyl diglycidyl ether, diglycidyl ether of 1,6-dihydroxynaphthalene, 9 Diglycidyl ether of 9,9-bis (4-hydroxyphenyl) fluorene, isocyanate modified product of bisphenol A type epoxy resin, diglycidylaniline, diglycidyl phthalate, diterephthalate Glycidyl esters, dimer acid diglycidyl ester, polyepoxides, and obtained by oxidizing a compound having two double bonds in the molecule.

The difunctional epoxy resin in the present invention is
100% by weight of a bifunctional epoxy resin having an epoxy equivalent of 750 or more, more preferably 900 or more, and further preferably 1000 or more.
It is preferable to contain 5 to 50% by weight. If the epoxy equivalent is less than 750, the cured resin does not exhibit sufficient tensile elongation at break, toughness, and plastic deformability, which is not preferable. By adding an appropriate amount of a bifunctional epoxy resin having an epoxy equivalent of 750 or more, it is possible to impart a higher degree of toughness and plastic deformability to the resin cured product and improve the strength of the fiber-reinforced composite material. The mixing ratio is 5% by weight
If it is less than that, the effect is not sufficient, so it is not preferable,
Further, when it exceeds 50% by weight, the viscosity of the uncured resin composition becomes too high, which may impair the impregnating property into the reinforcing fibers, the adhesiveness between the prepregs, the handling property such as the flexibility of the prepregs, etc. Absent.

The fact that the prepreg contains the bifunctional epoxy resin having an epoxy equivalent of 750 or more in such a mixing ratio means that the uncured epoxy resin composition is extracted from the prepreg with an organic solvent such as chloroform. , GPC, reverse phase chromatography, infrared absorption, ¹ H NMR, ¹³ C NMR for the extracted components,
It can be specified by performing a combination of methods such as mass spectrometry.

Further, the bifunctional epoxy resin in the present invention preferably contains a bisphenol F type epoxy resin in an amount of preferably 5 to 100% by weight, more preferably 20 to 90% by weight. By including the bisphenol F type epoxy resin in the present invention, the balance of properties such as viscoelasticity of the uncured resin composition, tensile fracture elongation of the resin cured product, toughness, plastic deformability, elastic modulus, heat resistance, etc. It is preferable because an excellent prepreg can be obtained. In particular, when a bifunctional epoxy resin having an epoxy equivalent of 750 or more, which tends to have a high viscosity, is contained, it is preferable to combine this with a bisphenol F type epoxy resin. The bisphenol F type epoxy resin may have an epoxy equivalent of less than 750, or the bisphenol F type epoxy resin itself may have an epoxy equivalent of 750 or more.

The epoxy resin composition of the present invention contains, in order to improve the heat resistance of the obtained fiber-reinforced composite tubular body,
It is preferable to include a polyfunctional epoxy resin having two or more epoxy groups in the molecule to the extent that the tensile rupture elongation, toughness and plastic deformability of the cured resin are not significantly impaired.

As the polyfunctional epoxy resin, tris (p-
Hydroxyphenyl) methane triglycidyl ether, tetrakis (p-hydroxyphenyl) ethane tetraglycidyl ether, glycerin triglycidyl ether, pentaerythritol tetraglycidyl ether, phenols and alkylphenols, novolaks obtained from phenol derivatives such as halogenated phenols Glycidyl ester, tetraglycidyldiaminodiphenylmethane, tetraglycidyl m-xylylenediamine, triglycidyl-m-aminophenol, triglycidyl-p-aminophenol, triglycidyl isocyanurate and the like.

As the curing agent for the constituent element (C) in the present invention, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, m-phenylenediamine, m- Active hydrogen such as aromatic amine having active hydrogen such as xylylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine, bis (aminomethyl) norbornane, bis (4-aminocyclohexyl) methane, dimer acid ester of polyethyleneimine An aliphatic amine having, an epoxy compound, an acrylonitrile, a phenol and formaldehyde, a modified amine obtained by reacting a compound such as thiourea with an amine having these active hydrogens, dimethylaniline, dimethylbenzylamine, 2,
4,6-tris (dimethylaminomethyl) phenol and 1-
Tertiary amines having no active hydrogen such as substituted imidazole, dicyandiamide, tetramethylguanidine, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, and carvone such as methylnadic anhydride. Acid anhydrides, polycarboxylic acid hydrazides such as adipic acid hydrazide and naphthalene dicarboxylic acid hydrazide, polyphenol compounds such as novolac resins, polymercaptans such as esters of thioglycolic acid and polyols, Lewis such as boron trifluoride ethylamine complex Examples thereof include acid complexes and aromatic sulfonium salts.

These hardening agents may be combined with a suitable hardening aid to enhance the hardening 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 combining the above as a curing aid are given.

In the present invention, the above-mentioned component (A),
In addition to (B) and (C), other components such as polymer compounds and organic or inorganic particles can be included.

A thermoplastic resin is preferably used as the polymer compound. By blending the thermoplastic resin, the effect of controlling the viscosity of the resin, controlling the handleability of the prepreg, or improving the adhesiveness is enhanced, which is preferable.

Examples of thermoplastic resins which 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 addition of the thermoplastic resin in an amount of 1 to 20 parts by weight based on 100 parts by weight of the epoxy resin gives the epoxy resin composition proper viscoelasticity, and a good composite material. It is preferable in that physical properties can be obtained.

An uncured epoxy resin composition which also contains the constituents (B) and (C) and, if necessary, other components and is present by being impregnated into the carbon fiber of the constituent (A) in the prepreg of the present invention. Regarding the viscoelasticity of the product, in order to obtain good handling of the prepreg, the measurement frequency is 0.5H.
z, storage modulus G ′ at 50 ° C. is 300 to 50000P
It is preferably a. If G'is less than 300 Pa, the adhesive strength between the prepreg surfaces (hereinafter referred to as the adhesive strength of the prepreg) is weak, and in the prepreg laminating step, the laminated prepregs are immediately peeled off to hinder the laminating work. It is not preferable because it may cause damage. If G'exceeds 50000 Pa, the flexibility of the prepreg deteriorates, the shapeability on the curved surface becomes insufficient, and the impregnability into the reinforcing fiber deteriorates, which is not preferable. Such viscoelasticity is achieved by optimizing the type and mixing ratio of the epoxy resin component contained in the constituent element (B), or by including an appropriate amount of the thermoplastic resin.

The prepreg of the present invention has an adhesive strength of 0.050 to 0.150 N, which is measured under the conditions described below, in order to produce a tubular body made of a fiber-reinforced composite material.
/ Mm ² is preferable. If the adhesive strength of the prepreg is less than 0.050 N / mm ² , the prepregs stacked in the prepreg laminating step may be immediately peeled off, which may hinder the laminating operation.
Further, if it exceeds 0.150 N / mm ² , it is not preferable because the correction work becomes difficult when the prepreg is bonded. When a tubular body is laminated using a prepreg that does not have such preferable adhesive strength, defects inside the tubular body, such as disorder of fiber orientation, are likely to occur, but in particular, a fiber composite material tubular tube to which a reinforcing fiber having a high elastic modulus is applied. In the case of the body, it is susceptible to strength reduction due to such defects. Therefore, in the case of the prepreg of the present invention to which the carbon fiber having the tensile elastic modulus of 330 GPa to 1000 GPa is applied, the adhesive strength is set to 0.
It is preferably 050 to 0.150 N / mm ² .

If a cover film or the like is not attached to the surface of the prepreg and the surface of the prepreg is left exposed to the atmosphere, the adhesive strength of the prepreg may decrease with time. Not only immediately after peeling off the cover film or release paper attached to the prepreg surface, but also after leaving the prepreg surface exposed to the air for 24 hours at 24 ° C. and 50% RH. Prepreg adhesive strength is 0.050
From the standpoint of work efficiency, it is preferably 0.150 N / mm ² .

In order to obtain the adhesive strength of such a prepreg, it is effective to control the viscoelasticity of the epoxy resin composition present in the prepreg within an appropriate range as described above. It is more preferable to control the amount of the epoxy resin composition (hereinafter referred to as the amount of surface resin) to be used, and the greater the amount of surface resin, the more the adhesive strength of the prepreg can be improved. The amount of surface resin can be controlled by adjusting conditions such as the impregnation pressure, the tension applied to the reinforcing fibers, and the temperature at which the epoxy resin composition is heated in the step of impregnating the carbon fiber with the epoxy resin composition.

In the fiber-reinforced composite material tubular body of the present invention, the constituent elements (A) are aligned in one direction,
In addition, it is preferable that at least one layer in which the fiber direction of the constituent element (A) is arranged at an angle of 20 ° to 90 # with respect to the longitudinal direction of the tubular body is included in the internal structure. By arranging the carbon fibers having the tensile elastic modulus of 330 GPa to 1000 GPa like the constituent element (A) at such an angle, it is possible to effectively increase the torsional rigidity of the lightweight tubular body. In particular, when the tubular body of the present invention is applied to a golf shaft, the component (A) is arranged at such an angle that the weight can be reduced while keeping the torsional rigidity and the torsional strength within appropriate ranges. Is particularly preferred.

In the tubular body made of the fiber-reinforced composite material of the present invention, the glass transition temperature of the cured product of the epoxy resin (hereinafter, simply referred to as a cured resin product) is preferably 80 ° C to 120 ° C. When the glass transition temperature of the resin cured product exceeds 120 ° C., the thermal stress remaining in the tubular body made of the fiber-reinforced composite material increases and the strength characteristics thereof may deteriorate, which is not preferable. When the glass transition temperature of the cured resin is less than 80 ° C., the resin softened by heat may cause clogging of the polishing machine when the surface is polished after being formed into a tubular body, which is not preferable. The glass transition temperature of the resin cured product is a value measured by a differential scanning calorimetry (DSC), but by measuring a sample cut out from the tubular body, the resin cured product contained in the tubular body can be measured. The glass transition temperature can be measured.

In order to impart high strength characteristics, impact resistance and the like to the tubular body made of the fiber-reinforced composite material of the present invention, the cured resin is subjected to the compact tension method according to ASTM-E399 or ASTM E4545-91. The mode I fracture toughness value G _{IC at the} early stage of crack growth of the resin cured product measured by the compliant SENB method is preferably 200 J / m ² or more, and more preferably 400 J / m ² or more.

In order to impart high strength properties and impact resistance to the tubular body made of the fiber-reinforced composite material of the present invention, the resin cured product has a tensile elongation at break of 8% measured in accordance with JIS K7113. The above is preferable. Here, the G _IC and the tensile elongation at break of the resin cured product are measured for a cured product obtained by subjecting the epoxy resin composition of the present invention to a heat treatment at 130 ° C. for 90 minutes.

Hereinafter, a method for producing a prepreg, which is preferably applicable to the present invention, and a method for laminating the prepregs and curing them by heating to obtain a tubular body will be described.

The prepreg of the present invention is produced, for example, by a method such as a wet method in which a matrix resin is dissolved in a solvent such as methyl ethyl ketone or methanol to reduce its viscosity and then impregnated, or a hot melt method in which the viscosity is reduced by heating and impregnated. be able to.

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

In the hot-melt method, carbon fibers are directly impregnated with a matrix resin whose viscosity is reduced by heating, or a film in which an epoxy resin composition is once coated on release paper is first prepared, and then carbon fibers 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.

In order to form a tubular body using the prepreg of the present invention, a method of laminating the prepreg and then heating and curing the resin while applying pressure to the laminate can be used.

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

The wrapping tape method is a method of winding a prepreg around a cored bar such as a mandrel to form a tubular body, and is suitable for producing rod-shaped bodies such as golf club shafts and fishing rods. 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 and applying pressure to the prepreg, and the resin is heated and cured in an oven, and then a core metal is applied. A tubular body can be obtained by pulling out.

In the 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, the tubular body can be formed by heating the mold.

[0048]

EXAMPLES The present invention will be described in detail below with reference to examples. The measurement of the surface area ratio of the carbon fibers, the preparation of the prepreg, the adhesiveness of the prepreg, the preparation of the tubular body, and the measurement of the physical properties of the tubular body were carried out by the following methods. (1) Surface area ratio measurement of carbon fiber The carbon fiber to be used for measurement is fixed on the sample stand, and Digital
An image of a three-dimensional surface shape is obtained using the Ruments NanoScope III under the following conditions.・ Probe: Si cantilever integrated probe (OMCL-AC120TS manufactured by Olympus Optical Co., Ltd.) ・ Measuring environment: room temperature atmosphere of 20 ° C to 30 ° C ・ Observation mode: tapping mode ・ Scanning speed: 0.3 to 0.4 Hz -Scanning range: 2.5 μm x 2.5 μm-Number of pixels: 512 x 512 For the entire image obtained, the software (NanoScope III version 4.22r2, primary Flatten) attached to the previous period was used.
Data is processed using a filter, a Lowpass filter, and a third-order Plane Fit filter) to calculate the actual surface area and projected area. The projected area was calculated by calculating the projected area on the quadric surface approximated in consideration of the curvature of the fiber cross-sectional area, and the surface area ratio was calculated by the following formula. Surface area ratio = actual surface area / projected area The same measurement was performed twice, and the average value was taken as the surface area ratio of the carbon fiber. (2) Preparation of prepreg The resin composition was applied onto release paper using a reverse roll coater to prepare a resin film having a resin areal weight of 20 g / m ² . Next, two resin films are superposed on both sides of the carbon fibers on the carbon fibers arranged in a sheet shape in one direction, and the temperature is 100 ° C.
The resin composition is impregnated by sandwiching it with a heated metal roll and applying heat and pressure.

After the impregnation, the release paper on one side is peeled off from the prepreg, the polyethylene film is attached to the surface on the peeled side, and the release paper is arranged on one side and the polyethylene film is wound on the other side. As a result, the carbon fiber areal weight is 125 g / m ² , and the carbon fiber content is 76% by weight.
I got a prepreg. (3) Measurement of adhesive strength of prepreg By the following operations (a) and (b), 24 ° C and relative humidity of 50
The adhesive strength of the prepreg was measured under the environment of% RH. (A) The prepreg used for measurement is 100 mm × 200 m
The prepreg A was cut into a size of m and firmly attached to a plastic plate having a flat surface with a double-sided tape. (B) On the surface of the prepreg A, a prepreg B cut from the same prepreg A and having a contact area of 10
4.5 so that it becomes mm × 10 mm (= 100 mm ² ).
After pressing for 1 second with N load, prepreg B is 30m
The peeling force at the time of peeling in the direction perpendicular to the prepreg A surface at a speed of m / min was measured, and this was measured as the contact area (
The value obtained by dividing by 00 mm ² ) was taken as the adhesive strength of the prepreg. (4) Manufacture of tubular body made of fiber composite material By the following operations (a) to (e), a fiber composite having a laminated structure of [0 ₃ / ± 45 ₃ ] in the cylinder axis direction and an inner diameter of 10 mm A tubular body made of material was produced. A round rod made of stainless steel having a diameter of 10 mm (length 1000 mm) was used for the mandrel. (A) 800 mm length x 1 width so that the fiber direction is 45 degrees with respect to the axial direction of the mandrel.
Two pieces were cut into a rectangle of 06 mm. The two sheets were attached with a shift of 16 mm (corresponding to half the mandrel circumference) so that the fiber directions intersect each other. (B) The laminated prepreg was wound around a release-treated mandrel so that the longitudinal direction of the prepreg and the axial direction of the mandrel were aligned. (Biasing material) (c) On top of that, a prepreg is cut into a rectangle of 800 mm length × 118 mm width so that the fiber direction is in the longitudinal direction so that the longitudinal direction of the prepreg and the axial direction of the mandrel are aligned. Wrapped around. (Straight material) (d) A wrapping tape (heat-resistant film tape) was wrapped around, and heat-molded in a curing oven at 130 ° C. for 90 minutes. (E) After molding, the mandrel was pulled out and the wrapping tape was removed to obtain a tubular body. (4) Measurement of glass transition temperature (Tg) of cured epoxy resin About measurement sample obtained by cutting out from tubular body,
It was measured by the DSC method according to JIS K7112. During the DSC measurement, the heating rate was 40 ° C./minute. (5) Measurement of Torsional Strength of Tubular Body A 400 mm long test piece was cut out from a tubular body having an inner diameter of 10 mm, and "Golf club shaft certification standard and standard confirmation method" (Product Safety Association, commonly known as the Minister of Industry 5 No. 2087, 1993), and the torsion test was performed. The gauge length of the test piece was 300 mm, and 50 mm at both ends of the test piece was held by a fixing jig. The twist strength was calculated by the following formula. The measurement was performed in an environment of 23 ° C. and a relative humidity of 50% RH.

Torsional strength (N ・ m ・ deg) = breaking torque (N ・ m
m) × twist angle at break (deg) (Example 1) The following raw materials were mixed with a kneader to obtain a resin composition in which polyvinyl formal was uniformly dissolved.

Bisphenol A type bifunctional epoxy resin (Epicoat 828, Japan Epoxy Resin Co., Ltd.)
Made, average epoxy equivalent 184-194) 40 parts Bisphenol A type bifunctional epoxy resin (Epicoat 1
001, Japan Epoxy Resin Co., Ltd., average epoxy equivalent 450-500) 30 parts phenol novolac type epoxy resin (Epicoat 15
4, Japan Epoxy Resin Co., Ltd., average epoxy equivalent 176-180) 15 parts Dicyandiamide (DICY7, Japan Epoxy Resin Co., Ltd.) 5 parts 3- (3,4-dichlorophenyl) -1,1-dimethylurea ( DCMU99, Hodogaya Chemical Co., Ltd. 4
Part Polyvinyl Formal (Vinylec K, Chisso Corporation)
4 parts) with this resin composition and a tensile elastic modulus of 38 aligned in one direction
A sheet-shaped prepreg (A-1) was produced according to the above-mentioned operation using carbon fiber having a surface area ratio of 1.02 and 2 GPa.

The adhesive strength of the obtained prepreg (A-1) was measured by the above-mentioned operation on the surface on the side where the polyethylene film was attached. The measurement is within 10 minutes after peeling off the polyethylene film, and at 23 ° C. and 50% RH with the surface exposed by peeling off the polyethylene film.
After being left for 24 hours in the above environment, the test was performed twice in total, and as shown in Table 1, all showed good adhesive strength.

Next, a carbon fiber having a tensile elastic modulus of 295 GPa and a surface area ratio of 1.090 was used, and the carbon fiber content was 76.
Prepreg P2255F-1 manufactured by Toray Industries, Inc. in weight%
2 was used as a straight material and prepreg (A-1) was used as a bias material to prepare a tubular body by the method described above, and its torsional strength and Tg of a resin cured product of the bias material were measured. The results are summarized in Table 1. (Example 2) The following raw materials were mixed with a kneader to obtain a resin composition in which polyvinyl formal was uniformly dissolved.

Bisphenol F type bifunctional epoxy resin (Epicoat 807, Japan Epoxy Resin Co., Ltd.)
Made, average epoxy equivalent 160-175) 55 parts bisphenol A type bifunctional epoxy resin (Epicoat 1009, Japan Epoxy Resin Co., Ltd., average epoxy equivalent 2400-3300) 30 parts phenol novolac type multifunctional epoxy resin (Epicoat 154 , Japan Epoxy Resin Co., Ltd., average epoxy equivalent 176-180) 15 parts Dicyandiamide (DICY7, Japan Epoxy Resin Co., Ltd.) 5 parts 3- (3,4-dichlorophenyl) -1,1-dimethylurea (DCMU99 , Hodogaya Chemical Co., Ltd.) 4
Part Polyvinyl Formal (Vinylec K, Chisso Corporation)
4 parts) with this resin composition and a tensile elastic modulus of 38 aligned in one direction
A sheet-shaped prepreg (A-2) was produced according to the above-described operation using carbon fibers having a surface area ratio of 1.02 and 2 GPa.

The adhesive strength of the obtained prepreg (A-2) was measured on the surface on the side where the polyethylene film was attached by the above-mentioned operation. The measurement was performed within 3 minutes after the polyethylene film was peeled off, and twice after the polyethylene film was peeled off and the surface was exposed in the environment of 23 ° C. and 50% RH for 24 hours. As a result, all showed good adhesive strength.

Next, prepreg P2255 manufactured by Toray Industries, Inc.
Using F-12 as a straight material, prepreg (A-2)
Was used as a bias material to prepare a tubular body by the method described above, and its twist strength and Tg of the resin cured product of the bias material were measured. The results are summarized in Table 1. (Example 3) The following raw materials were mixed with a kneader to obtain a resin composition in which polyvinyl formal was uniformly dissolved.

Bisphenol A type bifunctional epoxy resin (Epicoat 828, Japan Epoxy Resin Co., Ltd.)
Made, average epoxy equivalent 184-194) 55 parts bisphenol F type bifunctional epoxy resin (Epicoat 4010P, Japan Epoxy Resin Co., Ltd., average epoxy equivalent 4400) 30 parts phenol novolac type multifunctional epoxy resin (Epicoat 154, Japan Epoxy resin Co., Ltd., average epoxy equivalent 176 to 180) 15 parts Dicyandiamide (DICY7, Japan Epoxy Resin Co., Ltd.) 5 parts 3- (3,4-dichlorophenyl) -1,1-dimethylurea (DCMU99, Hodogaya) Chemical Industry Co., Ltd.) 4
Part Polyvinyl Formal (Vinylec K, Chisso Corporation)
4 parts) with this resin composition and a tensile elastic modulus of 38 aligned in one direction
A sheet-shaped prepreg (A-3) was produced using carbon fibers having a surface area ratio of 1.02 at 2 GPa according to the above-mentioned operation.

The adhesive strength of the obtained prepreg (A-3) was measured by the above-mentioned operation on the surface on the side where the polyethylene film was attached. The measurement is within 10 minutes after peeling off the polyethylene film, and at 23 ° C. and 50% RH with the surface exposed by peeling off the polyethylene film.
After being left for 24 hours in the above environment, the test was performed twice in total, and as shown in Table 1, all showed good adhesive strength.

Next, prepreg P2255 manufactured by Toray Industries, Inc.
Prepreg (A-3) using F-12 as a straight material
Was used as a bias material to prepare a tubular body by the method described above, and its twist strength and Tg of the resin cured product of the bias material were measured. The results are summarized in Table 1. Example 4 The following raw materials were mixed with a kneader to obtain a resin composition in which polyvinyl formal was uniformly dissolved.

Bisphenol F type bifunctional epoxy resin (Epicoat 807, Japan Epoxy Resin Co., Ltd.)
Made, average epoxy equivalent 160-175) 50 parts bisphenol A type bifunctional epoxy resin (Epicoat 1001, Japan Epoxy Resin Co., Ltd., average epoxy equivalent 450-500) 10 parts bisphenol A type bifunctional epoxy resin (Epicoat 1004, Japan Epoxy Resin Co., Ltd., average epoxy equivalent 875-975) 40 parts Dicyandiamide (DICY7, Japan Epoxy Resin Co., Ltd.) 5 parts 3- (3,4-dichlorophenyl) -1,1-dimethylurea ( DCMU99, Hodogaya Chemical Co., Ltd. 4
Part Polyvinyl Formal (Vinylec K, Chisso Corporation)
4 parts) with this resin composition and a tensile elastic modulus of 38 aligned in one direction
A sheet-shaped prepreg (A-4) was produced according to the above-mentioned operation using carbon fiber having a surface area ratio of 1.02 and 2 GPa.

The adhesive strength of the obtained prepreg (A-4) was measured by the above-mentioned operation on the surface on the side where the polyethylene film was attached. The measurement is within 10 minutes after peeling off the polyethylene film, and at 23 ° C. and 50% RH with the surface exposed by peeling off the polyethylene film.
After being left for 24 hours in the above environment, the test was performed twice in total, and as shown in Table 1, all showed good adhesive strength.

Next, prepreg P2255 manufactured by Toray Industries, Inc.
Prepreg (A-4) with F-12 as straight material
Was used as a bias material to prepare a tubular body by the method described above, and its twist strength and Tg of the resin cured product of the bias material were measured. The results are summarized in Table 1. (Comparative Example 1) The following raw materials were mixed with a kneader to obtain a resin composition in which polyvinyl formal was uniformly dissolved.

Bisphenol A type bifunctional epoxy resin (Epicoat 828, Japan Epoxy Resin Co., Ltd.)
Made, average epoxy equivalent 184-194) 15 parts biphenyl type bifunctional epoxy resin (Epicoat YX4
000, manufactured by Japan Epoxy Resins Co., Ltd., average epoxy equivalent 187-197, 40 parts phenol novolac type epoxy resin (Epicoat 15
4, Japan Epoxy Resin Co., Ltd., average epoxy equivalent 176 to 180) 45 parts Dicyandiamide (DICY7, Japan Epoxy Resin Co., Ltd.) 5 parts 3- (3,4-dichlorophenyl) -1,1-dimethylurea ( DCMU99, Hodogaya Chemical Co., Ltd. 4
Part Polyvinyl Formal (Vinylec K, Chisso Corporation)
5 parts) with this resin composition and a tensile elastic modulus of 38 aligned in one direction
A sheet-shaped prepreg (B-1) was produced according to the above-mentioned operation using carbon fiber having a surface area ratio of 1.02 and 2 GPa.

The adhesive strength of the obtained prepreg (B-1) was measured on the surface on the side where the polyethylene film was attached by the above-mentioned operation. The measurement is within 10 minutes after peeling off the polyethylene film, and at 23 ° C. and 50% RH with the surface exposed by peeling off the polyethylene film.
After being left for 24 hours in the above environment, the test was performed twice.

Next, prepreg P2255 manufactured by Toray Industries, Inc.
Prepreg (B-1) using F-12 as a straight material
Was used as a bias material to prepare a tubular body by the method described above, and its twist strength and Tg of the resin cured product of the bias material were measured. The results are summarized in Table 1, but the proportion of the bifunctional epoxy resin in the constituent element (B) is as low as 55% by weight, and therefore the torsional strength of the tubular body is low as compared with Examples 1 to 4. It became a value. (Comparative Example 2) The same resin composition as that of Example 2, a tensile elastic modulus of 377 GPa aligned in one direction, and a surface area ratio of 1.21.
A sheet-shaped prepreg (B-2) was produced according to the above-mentioned operation using the carbon fiber of No. 1.

The adhesive strength of the obtained prepreg (B-2) was measured on the surface on the side where the polyethylene film was attached by the above-mentioned operation. The measurement is within 10 minutes after peeling off the polyethylene film, and at 23 ° C. and 50% RH with the surface exposed by peeling off the polyethylene film.
After being left for 24 hours in the above environment, the test was performed twice.

Next, prepreg P2255 manufactured by Toray Industries, Inc.
Prepreg (B-2) using F-12 as a straight material
Was used as a bias material to prepare a tubular body by the method described above, and its twist strength and Tg of the resin cured product of the bias material were measured. The results are collectively shown in Table 1. Since the carbon fibers having a rough surface and a large surface area ratio were used, the torsional strength of the tubular body was lower than that in Example 2. (Example 5) The same resin composition as in Example 2, the tensile elastic modulus 475 GPa aligned in one direction, and the surface area ratio 1.04.
A sheet-shaped prepreg (A-5) was produced according to the above-mentioned operation using the carbon fiber of No. 1.

The adhesive strength of the obtained prepreg (A-5) was measured on the surface on the side where the polyethylene film was attached by the above-mentioned operation. The measurement was performed within 3 minutes after the polyethylene film was peeled off, and twice after the polyethylene film was peeled off and the surface was exposed in the environment of 23 ° C. and 50% RH for 24 hours. As a result, all showed good adhesive strength.

Next, prepreg P2255 manufactured by Toray Industries, Inc.
Prepreg (A-5) using F-12 as a straight material
Was used as a bias material to prepare a tubular body by the method described above, and its twist strength and Tg of the resin cured product of the bias material were measured. The results are summarized in Table 1. (Comparative Example 3) The same resin composition as that of Example 2, a tensile elastic modulus of 475 GPa aligned in one direction, and a surface area ratio of 1.25.
A sheet-shaped prepreg (B-3) was produced according to the above-mentioned operation using the carbon fiber of No. 1.

The adhesive strength of the obtained prepreg (B-3) was measured on the surface on the side where the polyethylene film was attached by the above-mentioned operation. The measurement is within 10 minutes after peeling off the polyethylene film, and at 23 ° C. and 50% RH with the surface exposed by peeling off the polyethylene film.
After being left for 24 hours in the above environment, the test was performed twice.

Next, prepreg P2255 manufactured by Toray Industries, Inc.
Prepreg (B-3) using F-12 as a straight material
Was used as a bias material to prepare a tubular body by the method described above, and its twist strength and Tg of the resin cured product of the bias material were measured. The results are summarized in Table 1, but because the carbon fibers having a rough surface and a large surface area ratio were used, the torsional strength of the tubular body was lower than that in Example 5. (Comparative Example 4) The following raw materials were mixed with a kneader to obtain a resin composition in which polyvinyl formal was uniformly dissolved.

Bisphenol F type bifunctional epoxy resin (Epicoat 807, Japan Epoxy Resin Co., Ltd.)
Made, average epoxy equivalent 160-175) 55 parts bisphenol A type bifunctional epoxy resin (Epicoat 1009, Japan Epoxy Resin Co., Ltd., average epoxy equivalent 2400-3300) 30 parts phenol novolac type multifunctional epoxy resin (Epicoat 154 , Japan Epoxy Resin Co., Ltd., average epoxy equivalent 176-180) 15 parts Dicyandiamide (DICY7, Japan Epoxy Resin Co., Ltd.) 5 parts 3- (3,4-dichlorophenyl) -1,1-dimethylurea (DCMU99 , Hodogaya Chemical Co., Ltd.) 4
Part Polyvinyl Formal (Vinylec K, Chisso Corporation)
3 parts) with this resin composition and a tensile elastic modulus of 47 aligned in one direction
A sheet-shaped prepreg (B-4) was produced in accordance with the above-mentioned operation using carbon fiber having a surface area ratio of 1.25 and 5 GPa.

The adhesive strength of the obtained prepreg (B-4) was measured on the surface on the side where the polyethylene film was attached by the above-mentioned operation. The measurement is within 10 minutes after peeling off the polyethylene film, and at 23 ° C. and 50% RH with the surface exposed by peeling off the polyethylene film.
After being left for 24 hours in the above environment, the test was performed twice.

Next, prepreg P2255 manufactured by Toray Industries, Inc.
Prepreg (B-4) using F-12 as a straight material
Was used as a bias material to prepare a tubular body by the method described above, and its twist strength and Tg of the resin cured product of the bias material were measured. The results are summarized in Table 1, but because the carbon fibers having a rough surface and a large surface area ratio were used,
Since the adhesive strength of the prepreg was not sufficient, the torsional strength of the tubular body was remarkably low as compared with Example 5.

[0075]

[Table 1]

[0076]

INDUSTRIAL APPLICABILITY The tubular body made of the fiber-reinforced composite material using the prepreg of the present invention has excellent torsional strength.
This makes it possible to obtain a tubular body made of a fiber-reinforced composite material, which has excellent impact strength and is also lightweight.

The tubular body made of the fiber-reinforced composite material of the present invention is suitably used for golf club shafts, fishing rods, bicycle frames, badminton racket shafts, bicycle frame / handles, wheelchair frames, hockey sticks and the like. You can

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4F072 AA04 AA07 AB10 AB22 AB24                       AD23 AD25 AD27 AD28 AD29                       AD33 AD34 AE01 AE02 AE04                       AF01 AG03 AG12 AG17 AK14                       AL03                 4J002 CD011 CD012 CD041 CD042                       CD051 CD062 CD101 CD131                       CD132 CD142 EL136 EN046                       EN076 ER016 ET006 ET017                       EU156 EV026 EV216 EV296                       EY016 FD146 FD157 GF00                       GT00                 4J036 AA01 AA02 AA05 AB17 AC01                       AD08 AD09 AG07 AJ02 AJ03                       AJ05 AK03 CB20 DA01 DA04                       DB06 DB15 DB21 DC02 DC03                       DC06 DC09 DC10 DC31 DC35                       DD02 FA02 FB07 FB08 GA03                       GA19 GA22 JA08 JA11 JA15

Claims (7)

[Claims] 1. A composition comprising the following constituents (A), (B) and (C), and 75 to 100% by weight of a bifunctional epoxy resin in 100% by weight of the constituent (B). A prepreg that is characterized by (A) The surface area ratio measured by an atomic force microscope is 1.
00 to 1.10 and a tensile elastic modulus of 330 GPa
~ 1000 GPa carbon fiber (B) epoxy resin (C) curing agent 2. In 100% by weight of a bifunctional epoxy resin,
Epoxy resin having an epoxy equivalent of 750 or more is 5 to 5
The prepreg according to claim 1, wherein the prepreg contains 0% by weight. 3. In 100% by weight of a bifunctional epoxy resin,
The prepreg according to claim 1 or 2, which comprises 5 to 100% by weight of a bisphenol F type epoxy resin. 4. The adhesive strength between the prepreg surfaces is 0.05.
0 to 0.150 N / mm ²Claims characterized by
The prepreg according to any one of Items 1 to 3. 5. A fiber-reinforced composite material tubular body comprising a layer formed by heat-curing the prepreg according to any one of claims 1 to 4. 6. The component (A) is aligned in one direction, and the fiber orientation of the component (A) in its internal structure is an angle of 20 ° to 90 # with respect to the longitudinal direction of the tubular body. The tubular body made of a fiber-reinforced composite material according to claim 5, wherein the tubular body is made of a fiber-reinforced composite material. 7. The fiber-reinforced composite material tubular body according to claim 5, wherein the glass transition temperature of the cured product of the epoxy resin is 80 ° C. to 120 ° C.