JPH0710289B2 - Golf club shaft - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a shaft used for a golf club, and more particularly to a shaft made of fiber reinforced resin having improved impact resistance.

(Prior Art) Conventionally, the mainstream of golf club shafts is made of metal, but in recent years, various fiber-reinforced resin shafts having advantages of light weight, high strength, and high elastic modulus have come to be used. It was

In the fiber-reinforced resin shaft, carbon fiber having excellent specific strength and specific elastic modulus is mainly used as the reinforcing fiber,
Other glass fibers, aramid fibers, boron fibers, alumina fibers, silicon carbide fibers and the like can also be used in combination.

Epoxy resin is mainly used as the matrix resin, but other unsaturated polyester resin, phenol resin,
Thermosetting resin such as polyurethane resin, polypropylene resin, polyphenylene sulfide resin, polyether ether ketone resin, polyether sulfone resin, ABS
A thermoplastic resin such as resin or nylon resin is used.

As a commonly-used shaft manufacturing method, a prepreg obtained by previously impregnating reinforcing fibers with a synthetic resin for a matrix is cut into a required size, and wound by a mandrel for molding, and a sheet winding method, or There is a filament winding method in which a roving-like reinforcing fiber is impregnated with a synthetic resin for a matrix and is wound around a mandrel for forming a shaft to be formed. In either case, the tape-shaped film is then tightly bound while applying tension so that pressure is applied during heat curing, and then heat cured. The film used at this time is generally polyester, polypropylene or the like. For the cured pipe, pull out the mandrel, peel off the tape film,
After polishing, the shaft is completed by painting.

(Problems to be solved by the invention) However, although a shaft in which carbon fibers are mainly used at present is used, carbon fibers have a specific strength,
It has excellent specific elastic modulus, but has the drawback of low elongation and poor impact strength. Therefore, such a shaft has a drawback that it breaks brittlely when an impact load is applied.

As a means for improving the above-mentioned drawbacks, it has been attempted to use aramid fibers in combination, but with aramid fibers which are anisotropic, the strength in the direction perpendicular to the fibers is insufficient, and the impact strength has not been satisfied. . In addition, the aramid fiber is difficult to cut and has poor machinability such as fluffiness, so that it is used only in a very limited manner.

Further, in the conventional molding method of the shaft, after laminating the reinforcing fibers on the mandrel, binding with a tape-like film is indispensable for ensuring the interlayer adhesion of the reinforcing fibers,
After heat-curing and molding, a step of peeling off the tape-shaped film wound up is required.

In addition, after peeling off the tape-shaped film, the surface must be polished to finish, but when polishing the surface, not only the matrix resin but also part of the reinforcing fiber is scraped off by polishing, so the strength of the shaft Affects the rigidity, etc. Therefore, when designing the shaft, it is necessary to set a cutting allowance to be cut by polishing in advance. In that case, there is a problem that the safety factor must be high in consideration of variations in reduction in strength and rigidity due to polishing.

(Means for Solving the Problems) In view of the above-mentioned conventional drawbacks, the present invention provides a lightweight fiber-reinforced resin,
The purpose of the golf club shaft is to provide a golf club shaft which is excellent in impact resistance, workability, and feel on shot without impairing the advantages of high strength and high elastic modulus.

That is, the present invention, the resin layer reinforced with reinforcing fibers, 20kg / m
A shaft which is obtained by winding and laminating a tape-like film having a tensile strength of m ² or more and consisting essentially of an organic polymer on the outermost layer of the shaft, and having a torsional strength.
A golf club shaft characterized by having a weight of 1.5 kg.m.

Carbon fiber is mainly used as the reinforcing fiber, and it is also possible to use glass fiber, aramid fiber, silicon carbide fiber, alumina fiber and the like in combination.

Thermosetting resin such as epoxy resin, unsaturated polyester resin, polyurethane resin, phenol resin or polypropylene resin, polyphenylene sulfide resin, polyether ether ketone resin, polyether sulfone resin, ABS resin, nylon resin, etc. Molding is performed by a filament winding method or a sheet winding method using a plastic resin as a matrix resin. After the tape-shaped film, which has a tensile strength of 20 kg / mm ² or more and is substantially made of an organic polymer, is wound and laminated on at least the outermost layer of the shaft, the shaft-formed body thus laminated is formed. Obtained by heating and curing.

The film used in the present invention is required to have a tensile strength of 20 kg / mm ² or more.

The tensile strength 20 kg / mm ² or more in the present invention means that the strength of the film in at least one direction is 20 kg / mm ² or more, for example, 20 kg / mm ² or more in one direction, It also includes a film having a strength of 20 kg / mm ² or less in the direction orthogonal to it.

Also, it is preferable that the tensile elastic modulus is high, and usually 700 kg / mm ²
It should be above.

These requirements must be satisfied in order to impart a strong binding force during molding and to prevent the physical properties of the resulting shaft from being reduced as much as possible.

More preferably tensile strength of 45 kg / mm ² or more and 1000 kg
It has a tensile elastic modulus of / mm ² or more. More preferably, the film has a tensile strength of 50 kg / mm ² or more, or a tensile elastic modulus of 1200 kg / mm ² or more.

The material for the film used in the present invention is not particularly limited as long as the above requirements are satisfied, but during the curing or melting operation of the fiber reinforced resin layer in molding, the film does not cause deterioration, decomposition, melting, etc. It is preferable that it is a substance, and as such a preferable organic polymer,
Aramid, polyimide, polyetheretherketone,
Examples thereof include wholly aromatic polyester, polybenzimidazole, and polybenzobisthiazole. Among them, aramid and polyimide are preferable from the viewpoint of good adhesiveness to resin and high strength and high elastic modulus which will be described below.

The aramid preferably used has the following general formula (I):
There are those having a structure represented by (II) or copolymers thereof.

(In the formula, R1, R2, R3 and R3 are 1 or 2 or more types thereof are selected.

Further, as the polyimide, for example, one represented by the following structural formula is preferably used.

These hydrogen atoms may be replaced with functional groups such as halogen, methyl, ethyl, methoxy, nitro and sulfone. m and n are average degree of polymerization and are about 50 to 1000.

The meaning that the film used in the present invention substantially consists of a specific organic polymer means that components other than the specific organic polymer may be contained in a small amount within a range that does not impair the effects of the present invention. That is, a small amount of an organic polymer other than the above, an organic low molecular compound, an inorganic compound or the like may be contained.

In the present invention, "integral" means that they are adhered by a resin layer, and in order to fully exert the reinforcing effect, the film and the matrix resin forming the shaft molded body have sufficient adhesive force. It is preferable to have.

A large adhesive force makes the surface of the film rough (devices on film formation, physical or chemical etching after film formation, etc.),
Introduce chemically active species to the surface (corona discharge treatment, plasma treatment, chemical decomposition, etc.), perform impregnation pretreatment for adhesion (epoxy compound, isocyanate compound, resorcin / formalin / latex mixture, etc.), or combine these Is preferably used and achieved thereby.

The thickness of the film used in the present invention is usually 2 to 100 μm.
And preferably 5 to 50 μm. If it is less than 2 μm, the operability is poor, and it takes a lot of time to wind it to have an appropriate thickness. On the other hand, if it exceeds 100 μm, the wound thickness is too large and there is no room to control the thickness. Therefore, it is not suitable.

In addition, the film is laminated by spirally winding a film having a width of 100 mm or less at which a sufficient binding force can be obtained when the fiber reinforced resin layer is wound by a taping method, at an appropriate pitch.

When laminating such a film by winding, it is necessary that the layers between the film and the film are also integrated. For example, if necessary, an adhesive or the like is applied to at least one side of the film in advance, and the film is wound while applying the adhesive. And the like are used. In special cases, it may also be wound alternately with a film adhesive. The adhesive is not particularly limited as long as it has sufficient adhesive force with the base material. For example, a method in which an epoxy resin or the like is applied on one surface of the film and the components are cured and integrated during the curing and molding of the shaft is a very preferable embodiment.

When the tape-shaped film is wound, it can be wound over the entire length, but for example, it can be wound in many places where strength is particularly required or in the vicinity of the grip part where stress is not concentrated so much. .

In this case, a method of using a tape-shaped film and spirally taping while appropriately changing the pitch is preferable because the winding thickness can be easily changed by changing the density of the pitch.

The film used in the present invention can be integrated at the same time as the molding of the shaft, or can be further wound and laminated on the shaft after curing and molding, or can be partially wound around the shaft to be integrated and reinforced.

When the head is attached to the tip of the shaft and used as a golf club, the normally required adhesive strength between the head and the shaft is 0.8 kg / m or more in torsional strength. Considering such a torsional load and considering safety, the shaft of the present invention needs to have a torsional strength of 1.5 kg / m or more.

(Operation) Since the film wound and laminated on the molded shaft of the present invention has a thickness of 5 to 50 μm and has substantially isotropic mechanical properties, the film can be manufactured without increasing the weight of the shaft so much. Impact resistance, bending strength, and twist strength can be improved.

(Example) The Example of this invention is described based on drawing.

FIG. 1 shows the appearance of the shaft 1 of the present invention, which is an example in which a film is laminated on the outermost layer by taping.
FIG. 2 is a sectional view taken along the line AA in FIG. 1, and FIG. 3 is taken along the line BB in FIG.
It is a line expansion sectional view, and has shown the state where film layer 3 was laminated and integrated outside the fiber reinforced resin layer 2 which constitutes a shaft. The shaft 1 of the present invention is as follows: 1) A tapered stainless mandrel treated with a release agent is used as a mold, 2) Fiber reinforced resin prepreg is appropriately cut out, and the sheet is molded using a sheet rolling device. 5 kg / cm ²
3) Then, using a taping device, slit an aramid film with a thickness of 15 μm and a tensile strength of 40 kg / mm ² (coated with epoxy resin on one side) with a taping device at a tension of 4.5 kg and pitch. Wrap with 3mm, 4) 90 ℃ (1 hour), 130 ℃ (2 hours) in a heating furnace
After curing at the temperature of 5), 5) the mandrel was taken out, the surface was polished, and then coated and dried to manufacture the product.

The torsion strength of the shaft thus obtained was examined. As shown in FIG. 4, the measuring method is as follows. The tip of the shaft is bonded to the tip chuck jig 4, the jig is held by the rotary chuck 5, and the rotation speed of the rotary chuck is set to 395.
It was rotated at ° / minute, and the maximum torsional moment when the shaft was broken was taken as the torsional breaking strength. The results were 1.4 kg · m for the non-rolled laminated aramid film of Comparative Example and 1.7 kg · m for the product of the present invention.

(Comparative Example) A shaft was molded in the same procedure as in Example except that a polyethylene terephthalate release tape was used instead of the aramid film, and finally the polyethylene terephthalate tape was peeled off to obtain a comparative shaft. Table 1 shows the physical properties of the shafts of Examples and Comparative Examples.

(Effects) As described above, the shaft of the present invention has a structure in which a tape-shaped film is wound and laminated on at least the outermost layer of a molded article made of a fiber-reinforced resin to be integrated, and the film has mechanical properties Since it has almost isotropic property and its tensile strength is especially large, the torsional strength can be increased to 1.5 kgm or more without increasing the weight of the shaft so much, and the bending strength and impact strength can be increased. Can be improved.

In addition, unlike the prior art, there is no need for a step of peeling the tape-shaped film after molding, and since the fiber-reinforced resin layer of the shaft is not polished, the strength and rigidity of the shaft are hardly changed.

Since the tape-like film is integrated with the shaft molded body by the resin layer, the tape-shaped film may be wound after curing and molding the shaft, or may be partially wound and laminated to reinforce in order to increase the strength.

Further, when the golf club is placed in or taken out of a caddy bag or is transported, or the coating is peeled off due to contact during use of the club, the fiber reinforced resin layer may be worn, leading to a decrease in strength. Since the shaft is provided with a film having excellent impact resistance as the outermost layer, it is possible to prevent these, and since the vibration absorbing property is good, an extremely excellent shot feeling can be obtained.

[Brief description of drawings]

1 to 3 are explanatory views according to the present invention.
The figure is an external view of the shaft, FIG. 2 is a sectional view taken along the line AA in FIG. 1, and FIG. 3 is an enlarged sectional view taken along the line BB. Figure 4 shows
It is explanatory drawing of the method of measuring twist strength. 1: Shaft, 2: Fiber reinforced resin layer, 3: Film layer, 4: Tip chuck jig, 5: Rotating chuck.

Claims (4)

[Claims] 1. A resin layer reinforced with reinforcing fibers, comprising 20 kg / mm ²
A shaft formed by winding and laminating a tape-like film substantially made of an organic polymer having the above tensile strength on the outermost layer and having a torsional strength of 1.5 kg · m or more. And a golf club shaft. 2. The golf club shaft according to claim 1, wherein the tape-shaped film is wound and laminated integrally over the entire length of the shaft. 3. The golf club shaft according to claim 1, wherein the tape-shaped film is formed by partially winding and laminating the shaft. 4. The golf club shaft according to claim 1, wherein the tape-shaped film is loosely or densely wound and integrally laminated.