JPH03168167A - Golf club shaft - Google Patents

Abstract

PURPOSE:To enhance impact resistance, bending strength and twist strength by integrally forming a film layer substantially composed of an org. polymer having no m.p. at a specific temp. and having specific tensile strength to the innermost layer and/or between layers of a shaft formed of a fiber reinforced resin sheet to specify the Charpy impact strength thereof. CONSTITUTION:A film layer substantially composed of an org. polymer having no m.p. at below 300 deg.C and having tensile strength of 20kg/mm<2> or more is integrally formed to the inner most layer and/or between layers of a shaft having a taper formed of a fiber reinforced resin to form a golf shaft having Charpy impact strength of 30kg/cm or more. For example, an aramid film 2 whose single surface is coated with an epoxy resin is wound around and laminated to a mandrel having a taper and one wherein the film 2 is laminated to a carbon fiber reinforced prepreg 3 delivered in a fan shape is wound around the mandrel on the outside of the film 2 using a sheet rolling apparatus to be cured under heating.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a tapered golf club shaft;
In particular, it relates to a shaft made of fiber-reinforced resin with improved impact resistance.

(Prior Art) In the past, golf club shafts were mainly made of wood or metal, but in recent years shafts made of fiber-reinforced resin, which have the advantages of light weight, high strength, and high modulus of elasticity, have come into use.

In these shafts, the reinforcing fibers have specific strength,
Carbon fiber, which has excellent specific elasticity, is mainly used, and other materials such as glass fiber, aramit fiber, boron fiber, alumina fiber,
It is also possible to use a combination of silicon carbide fibers and the like.

The main matrix resin is epoxy resin, but other resins include unsaturated polyester resin, phenol resin,
Thermosetting resins such as polyurethane resins, polypropylene resins, polyphenylene sulfide resins, polyetheretherketone resins, polyethersulfone resins, ABS
Thermoplastic resins such as resins and nylon resins are used.

A commonly used manufacturing method for fiber-reinforced resin shafts involves winding and laminating a stretched sheet of the above-mentioned reinforcing fibers and a woven fabric impregnated with the above-mentioned matrix resin to form a blob leg around a shaft-forming mandrel. There is a sheet winding method in which the reinforcing fibers are aligned in one direction and impregnated with the matrix resin and filament winding is performed. In each case, a tape-shaped film is wrapped over the top, heat cured, and then the tape is removed, followed by polishing, painting, and molding.

In addition, JP-A-5-4-4-5-3-8-3 + Japanese Patent Publication No. 58-293 discloses that a thermoplastic resin film sheet is inserted into the middle layer of a brippreg for shaft molding to prevent warping or delamination of fishing rods. A tubular body is disclosed.

(Problem to be solved by the invention) However, in conventional shafts mainly made of carbon fiber, carbon fiber has low elongation and poor impact resistance, so the shaft may be damaged due to repeated stress concentration such as when hitting a ball. In order to prevent this, reinforcing materials are partially inserted, but while these reinforcing materials strengthen the shaft, they also make some parts hard, which adversely affects flexibility and increases weight.

In addition, there is a problem in absorbing shock or vibration during a shot, resulting in a so-called poor shot feel during a shot. Although aramid fibers have been used in combination as a means to improve these problems, aramid wk fibers are anisotropic, meaning that their strength in the direction perpendicular to the fibers is insufficient, making it difficult to meet the impact strength requirements. Of course, if you try to satisfy the impact strength, the rigidity will become too large, and i! The amount of f is deposited.

In addition, aramid fibers are difficult to cut, tend to lint, and have poor machinability, so their use is extremely limited.

(Means for Solving the Problems) In view of these points, the present invention provides excellent impact resistance and processability without sacrificing the advantages of fiber-reinforced resin, such as light weight, high strength, and high modulus of elasticity. This was done for the purpose of providing a golf club shaft with excellent feel.

That is, the present invention uses a substantially organic material that does not have a melting point below 300°C and has a tensile strength of 20 kg/mni2 or more in the innermost layer and/or between the layers of a shaft formed of a fiber reinforced resin sheet. It is made by integrally forming a film layer made of polymer, and has a Charpy impact strength of 30.
This is a shaft for a golf club, characterized in that it is kg-am.

As the reinforcing fibers used in the present invention, carbon fibers, glass fibers, aramid fibers, silicon carbide fibers, alumina fibers, etc. can be used alone or in combination.

Matrix resins used in the present invention include thermosetting resins such as epoxy resins, unsaturated polyester resins, polyurethane resins, and phenol resins, or polypropylene resins, polyphenylene sulfide resins, polyether ether ketone resins, polyether sulfone resins, and ABS resins. , thermoplastic resin such as nylon resin can be used.

The film used in the present invention requires the following requirements. First of all, the film must be substantially composed of an organic polymer that does not have a melting point below 300°C.

If the melting point is less than 300°C, the resin will harden, etc.
It is not preferable because it melts or is thermally deformed during the tU manufacturing process.

Next, the film needs to have a tensile strength of 20 kg/mmλ or more. In the present invention, the tensile strength of 20 kg/m or more means that the tensile strength of the film in at least one direction is 20 kg/m or more, for example, 20 kg/m or more in one direction. / mm2 or more, and the strength in the direction perpendicular to the strength is 20 kg/mni2 or less.

In addition, the tensile modulus is preferably higher than 700 kg/
It is preferable that m1 or more.

These requirements must be met in order not to deteriorate the physical properties of the resulting shaft. More preferably 45
Tensile strength of more than 1 kg/m and 1000 kg/m
It has a tensile modulus of elasticity of 1 or more. More preferably, the film has a tensile strength of 50 kg/m♂ or more, or 1200 kg/m♂ or more.
...has a tensile modulus of m2 or more.

The material for the film used in the present invention is not particularly limited as long as the above requirements are met, but the material does not cause deterioration, decomposition, melting, etc. during the curing or melting operation of the fiber reinforced resin layer during molding. Preferred organic polymers include aramid, polyimide, polyetheretherketone, wholly aromatic polyester, polybenzimidazole,
Polyhenzohis. Examples include thiazole, but aramid and polyimide are preferred because of their good adhesion to resins, high strength, and ease of developing high elastic modulus.

Preferably used aramit has the following general formula (1),
There are those having the structure represented by (II) and copolymers thereof.

0 0 or ←C -R 3-N H-+n (
IT) 11 0 (wherein R1, R2, R3 and R3 are selected from).

Also, examples of polyimide include: In the structural formula below Those expressed are preferably used.

O U These hydrogen atoms may be substituted with a functional group such as halogen, methyl, ethyl, methoxy, nitro, or sulfone.

mS n is the average degree of polymerization and is about 50 to 1,000.

The meaning that the film used in the present invention consists essentially of a specific organic polymer does not mean that components other than the above-mentioned specific organic polymer may be contained in small amounts within a range that does not impair the effects of the present invention. For example, small amounts of organic polymers, organic low-molecular compounds, inorganic compounds, etc. other than those mentioned above may be contained.

In the present invention, integrally forming means that the film and the fiber-reinforced resin sheet are bonded together with a resin layer, and in order to fully exhibit the reinforcing effect, the film and the shaft molded body are configured. It is preferable that the matrix resin has sufficient adhesive strength.

A large adhesion force can be achieved by roughening the surface of the film or tape (devices in film formation, physical or chemical etching after the film, etc.), or by introducing chemically active species to the surface (corona discharge treatment, plasma treatment, chemical decomposition, etc.), impregnation pretreatment for adhesion (epoxy compounds, isocyanate compounds,
Preferably, methods such as resorcinol, formalin, latex mixture, etc.) or a combination of these are used,
This will make you more powerful.

The thickness of the film used in the present invention is appropriately determined in consideration of the laminated structure with the fiber-reinforced resin layer in the molded product, but is usually 2 to 100 g. m, preferably from 5 to
It is 50 μm.

If it is less than 2 μm or more than 10,071 m, it is not suitable because the operability is poor and it is difficult to control the thickness of the film layer.

When winding and laminating such films, it is necessary to integrate the layers between the films. For example, if necessary, an adhesive or the like may be applied to at least one side of the film in advance, or the film may be rolled while being coated with an adhesive. A method such as rotating is used. In special cases, alternating wrapping with adhesive film may also be used. The adhesive is not limited in any way as long as it has sufficient adhesion to the base material.

-11- When a ball is hit with a golf club, stress is concentrated on the neck of the shaft, but in a club with a relatively long neck like a conventional wooden head, stress is not concentrated when hit. On the other hand, a head made of metal or the like with a short neck portion has a high rigidity of material, so stress tends to be concentrated during hitting. Further, in a head made of a material with high rigidity as described above, there is a risk that the end face of the neck portion may damage the shaft. In order to avoid damage due to such stress concentration, the shaft l of the present invention must have a Charpy impact value of 30 kg-(4) or more.

In the shaft of the present invention, a bribbed leg is formed from the reinforcing fibers and a matrix resin, the bribbed leg is cut out as appropriate for shaft molding, and the film is previously wound around the mandrel when the bribbed leg is wound and laminated on a tapered mandrel for shaft molding. After turning, the shaft is heated and hardened by wrapping the brie leg around it. Furthermore, when winding the brev legs around the tapered mantle, a film layer can also be provided between the brev legs.

-12- (Function) The shaft of the present invention has a film having a thickness of 5 to 507 mm and having approximately isotropic mechanical properties integrated into the innermost layer of the shaft and/or between the layers. Because of this, it is possible to improve the cutting impact resistance, bending strength, and torsional strength without significantly increasing the weight of the shaft. Furthermore, it is also possible to change the rigidity by changing the amount of film M and the location where the films are laminated.

(Example) An example of the present invention will be described based on the drawings. Figures 1 to 3
The figure is an explanatory diagram related to the present invention, and FIG. 1 shows the shaft 1.
Fig. 2 is a cross-sectional view taken along the line a-a in Fig. 1, and is an explanatory view of the first embodiment. Fig. 3 is a cross-sectional view taken along the line b-b of Fig. 1, and is an explanatory view of the second embodiment. It is a diagram.

Example 1: An aramid film 2 coated with epoxy resin on one side is wound around a tapered mandrel treated with a mold release agent, and the film 2 is laminated on the outside of this film onto a carbon fiber-reinforced rib 3 cut into a fan shape. , and wrap it around a mandrel using a sheet rolling device. Thereafter, it is molded by heating and curing.

Example 2: Aramid film 2 was laminated to a portion approximately 3001 IIm from the tip of the pre-reg shaft, laminated on a tapered mandrel by a conventional method, and then heat-formed.

(Comparative Example) A shaft that was heat-cured and molded using the conventional sheet winding method without providing an aramid film layer was used as a comparative shaft.

The method of measuring the impact strength of the shafts of Example 1.2 and Comparative Example is as shown in FIG. 4, with support at both ends and central load, and test pieces are taken at 120-meter intervals from the tip.

The capacity of the Charpy impact tester is 10 kg-m.

The measurement results are shown in Table 1.

-14 Table 1) (Effects) The shaft of the present invention has a film having a thickness of δ to 50 μm and having approximately isotropic mechanical properties in the innermost layer and/or between the layers of the fiber-reinforced resin sheft. Because of its structure, it exhibits greater bending strength than conventional shafts without significantly increasing the weight of the shaft.
Additionally, impact resistance has been significantly improved.

In addition, when providing between layers, it is possible to adjust the ratio of the film layer to the carbon fiber reinforced resin layer by adjusting the thickness of the film, the amount of winding between the layers, etc. to suit the golfer's preference. It is easy to change the rigidity of the shaft accordingly, furthermore, turbulent vibrations are eliminated and the feel at impact is greatly improved.

Furthermore, since the fiber-reinforced resin layer is sandwiched between the films, the occurrence of cracks is effectively suppressed, and both strength and impact resistance can be further improved.

In addition, if it is installed in areas that particularly require strength without changing the rigidity too much, such as the neck where stress is concentrated during impact, it can improve strength and impact resistance without significantly affecting the bending of the shaft. I can do it.

[Brief explanation of the drawing]

FIGS. 1 to 3 are explanatory views relating to the present invention, in which FIG. 1 is an external view of the shaft, FIG. 2 is a sectional view taken along line a-a in FIG. FIG. 3 is a sectional view taken along line bb in FIG. 1, and is an explanatory diagram of the second embodiment. FIG. 4 is an explanatory diagram of a method for measuring Charpy impact strength. 1: Shaft, 2: Film, 3: Bribrekyu-16- Tsukayoshi

Claims (1)

[Claims] 1. The innermost layer and/or between the layers of a tapered shaft formed of a fiber-reinforced resin sheet does not have a melting point below 300°C and has a tensile strength of 20 kg/mm^2 or more. It is made by integrally forming a film layer consisting essentially of an organic polymer, and has a Charpy impact strength of 30K.
A golf club shaft characterized by having a diameter of gcm or more. 2. The golf club shaft according to claim 1, wherein the film layer is provided over the entire length of the shaft. 3. The golf club shaft according to claim 1, wherein the film layer is provided partially on the shaft.