JP3007030B2 - Method for manufacturing hollow shaft made of FRP - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a hollow shaft made of FRP, which is used as a shaft for a golf club, a fishing rod, etc., by a sheet wrapping method. The present invention relates to a production method used when a prepreg having a low content is used.

[0002]

2. Description of the Related Art In recent years, as a shaft for a golf club,
FRP products (so-called black shafts) using carbon fiber as a main fiber reinforcing material are frequently used. This FRP shaft is usually formed by winding a sheet-shaped prepreg obtained by impregnating a thermosetting resin into rovings aligned in parallel and winding the prepreg on a mandrel, heating and curing the prepreg, and then removing the mandrel. Wrapping method).

In this case, in manufacturing a golf club shaft by the sheet wrapping method, in order to facilitate the winding of the prepreg around the mandrel and to improve the productivity, the starting end of the prepreg is attached to the mandrel before winding the prepreg. It is wound from. In this case, in the production of a golf club shaft by a conventional sheet wrapping method, a prepreg having a relatively high resin content (about 33% by weight) is usually used, and the prepreg surface has a certain degree of tackiness due to the resin in the prepreg. Because of this, the starting end of the prepreg is pressed against the mandrel to attach the starting end to the mandrel.

[0004]

At present, golf club shafts are required to be reduced in weight in order to facilitate swinging and improve flight performance. Therefore, in the production of a golf club shaft by the sheet wrapping method, a method of using a lightweight prepreg having a low content of a resin having a large specific gravity has been adopted for the purpose of reducing the weight of the shaft. That is, while the resin content of the conventional prepreg was about 33% by weight, the resin content was 3% in the manufacture of a lightweight shaft.
Prepreg is used in an amount of 0% by weight or less, especially about 27% by weight.

[0005] Such a prepreg having a resin content of 30% by weight or less has a low resin content and a small amount of resin existing on the surface portion, so that the surface does not have sufficient tackiness. Therefore, the starting end of the prepreg is simply pressed against the mandrel. Cannot be attached to the mandrel. Therefore, at present, the starting end of the prepreg easily adheres to the mandrel by adopting a method of pressing the mandrel while heating the starting end of the prepreg with an iron, improving the resin, or using a heating mandrel However, the fact is that this results in a decrease in productivity and an increase in manufacturing cost.

[0006] Recently, it has been required to use an ultra-light prepreg whose resin content is reduced to 25% by weight or less in order to further reduce the weight of the shaft. Without
Even if methods such as heating the prepreg, improving the resin, and using a heating mandrel cannot be attached to the mandrel, the winding of the prepreg around the mandrel becomes very troublesome, and the productivity is significantly reduced. .

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and when a FRP hollow shaft is manufactured by a sheet wrapping method using a prepreg having a low resin content and a low adhesiveness on the surface, the starting end of the prepreg is required. Can be easily and inexpensively attached to the mandrel, so that the prepreg can be easily wound around the mandrel, the cost can be reduced, and the productivity of lightweight shafts and ultra-lightweight shafts can be improved, and manufacturing costs can be reduced. The aim is to provide a method.

[0008]

In order to achieve the above object, the present invention provides a method of manufacturing a hollow shaft made of FRP as shown in the following (1) to (3). (1) After wrapping a prepreg having a resin content of 30% by weight or less around a mandrel, the prepreg is cured to form an FRP.
A method for producing a hollow shaft made of FRP, comprising: before winding a prepreg around a mandrel, attaching a starting end of the prepreg to the mandrel with an adhesive or an adhesive tape, and then winding the prepreg around the mandrel.

(2) After wrapping a prepreg having a resin content of 30% by weight or less around a mandrel and curing the prepreg to obtain a hollow shaft made of FRP, the starting end of the prepreg is double-sidedly adhered before winding the prepreg around the mandrel. A method for producing a hollow shaft made of FRP, comprising: attaching the prepreg to a mandrel with a tape, winding the prepreg around the mandrel, and peeling the tape from the inner wall of the shaft after shaping.

(3) After winding a prepreg having a resin content of 30% by weight or less around a mandrel, and curing the prepreg to obtain an FRP hollow shaft, the start of the prepreg is accelerated before the prepreg is wound around the mandrel. A method of manufacturing a hollow shaft made of FRP, comprising: attaching a prepreg to a mandrel with an adhesive containing a catalyst, and then winding the prepreg around the mandrel.

In the present invention, since the starting end of the prepreg is attached to the mandrel without using the adhesive force of the resin contained in the prepreg by using an adhesive or a pressure-sensitive adhesive tape, the resin content of the surface having poor tackiness is reduced. Even if the prepreg is less than 25% by weight, and even less than 25% by weight, its starting end can be easily attached to the mandrel at a low cost regardless of the resin content, so that the prepreg having a low resin content can be wound around the mandrel. It can be simplified and reduced in cost.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The mandrel used in the present invention has a shape corresponding to the hollow shaft to be molded, and can be formed in any shape such as a column, an ellipse, a prism, etc. When the hollow shaft is used as a golf club shaft, the hollow shaft has a somewhat tapered cylindrical shape.

In the present invention, as the prepreg, for example, a sheet-like material prepared by impregnating a thermosetting resin into a fiber reinforced material such as a roving, cloth, or mat which is aligned in parallel can be used. In this case, one or more of carbon fiber, glass fiber, metal fiber, aramid fiber, silicon carbide fiber, alumina fiber, boron fiber and the like as the fiber reinforcing material, epoxy resin as the thermosetting resin,
At least one kind of phenolic resin, unsaturated polyester resin, and the like, and a curing agent, a curing accelerator, a filler, a release agent, a pigment, and the like can be used as auxiliary materials. When the hollow shaft is used as a golf club shaft, a prepreg that uses carbon fiber, boron fiber as a fiber reinforcing material, and an epoxy resin, a phenol resin, or an unsaturated polyester resin as a resin is suitable.

The present invention relates to a method of manufacturing a hollow shaft made of FRP by a sheet wrapping method using a prepreg having a resin content of 30% by weight or less, usually 25 to 27% by weight. Before winding, the starting end of the prepreg is attached to the mandrel with an adhesive or an adhesive tape (double-sided adhesive tape or single-sided adhesive tape). The resin content of the prepreg is the ratio of the weight of the resin to the total weight of the prepreg, and the weight of the resin includes the weight of auxiliary materials such as a curing agent, a filler, and a release agent.

When an adhesive or a double-sided pressure-sensitive adhesive tape is used, an adhesive or a double-sided pressure-sensitive adhesive tape 8 is interposed between the mandrel 2 and the starting end 6 of the prepreg 4, as shown in FIG. In this case, the adhesive or the double-sided adhesive tape 8 may be applied or affixed to either the mandrel 2 or the prepreg 4 before the prepreg 4 is attached.
When a single-sided adhesive tape is used, for example, as shown in FIG. 1B, a single-sided adhesive tape 10 is attached from above the prepreg 4 so as to cover both the mandrel 2 and the starting end 6 of the prepreg 4. The adhesive or the adhesive tape may be provided over the entire length of the prepreg starting end, or may be provided only on a part thereof.

Although the kind of the adhesive is not limited, an adhesive having a high curing speed and a high adhesive strength is desirable for improving the productivity. In this respect, an epoxy adhesive, a cyanoacrylate adhesive, An adhesive or the like obtained by adding a curing acceleration catalyst to an unsaturated polyester resin can be suitably used. Among them, a cyanoacrylate-based adhesive is preferable because it has quick drying properties and moderate heat deterioration properties, and is easy to release from a mandrel. When an adhesive is used to attach the prepreg, it is necessary that the adhesive be substantially integrated with the FRP of the shaft after heat curing of the prepreg and have no effect on the shaft characteristics. This can be achieved by using agents and adjusting the amounts.

The kind of the adhesive tape is such that an adhesive layer made of glue, a dextrin-modified synthetic resin, an epoxy polyamine resin, an epoxy polyamide resin, a phenol resin, a resorcinol resin, etc. is provided on both sides or one side of a base material made of paper or cloth. Can be used. The pressure-sensitive adhesive may or may not be substantially integrated with the FRP of the shaft after the prepreg is heated and cured, but the amount of the pressure-sensitive adhesive does not affect the shaft characteristics even in the latter case.

When a double-sided pressure-sensitive adhesive tape is used as the pressure-sensitive adhesive tape, as can be seen from FIG. 1A, the tape can be peeled off from the inner wall of the shaft after the shaft is formed, thereby preventing the pressure-sensitive adhesive tape from affecting the shaft characteristics. be able to. When doing this, paper or
It is preferable to use a double-sided pressure-sensitive adhesive tape using a silicone-based pressure-sensitive adhesive as the cloth or pressure-sensitive adhesive, thereby facilitating tape peeling and reducing tape cost.

When a single-sided adhesive tape is used as the adhesive tape, as can be seen from FIG. 1B, the tape cannot be peeled off from the inner wall of the shaft after the shaft is formed. Therefore, the tape by weight does not impair the weight of the sheet Yafuto (within about 2~3g if golf club shaft).

In the present invention, the prepreg starting end is attached to the mandrel as described above, and after the prepreg is wound around the mandrel, the prepreg is cured, and the mandrel is pulled out of the molded product. An ultra-lightweight FRP hollow shaft is obtained.

When the production method of the present invention is carried out, the following means (a) to (c) can be used in combination, if necessary. (A) The end of the prepreg can be pressed down on the prepreg existing inside by an adhesive or an adhesive tape. That is, the resin content is 30% by weight or less, especially 2% by weight.
Since the prepreg of 7% by weight or less has poor surface adhesiveness, the end portion does not adhere to the prepreg existing inside when the winding is completed, and the end portion jumps up. Can be prevented. (B) When a plurality of prepregs are wound simultaneously on a mandrel in a stacked state, the starting end of the innermost prepreg is attached to the mandrel with an adhesive or an adhesive tape, and each prepreg outside of the prepreg is bonded to the inner prepreg. It can be attached by an agent or an adhesive tape. Thereby, the workability when a plurality of prepregs are stacked and wound on a mandrel can be improved. (C) When the prepreg is further wound on the prepreg of the mandrel around which the prepreg is wound, the starting end of the prepreg to be wound can be attached to the prepreg on the mandrel by an adhesive or an adhesive tape. Thereby, the workability when the prepreg is further wound on the prepreg can be improved.

The mode of use of the adhesive or pressure-sensitive adhesive tape in the means (a) to (c) is the same as that shown in FIG. In the case where an adhesive tape is used in the means (a) to (c), the adhesive tape cannot be removed from the formed shaft, which impairs the weight reduction of the shaft.
It is desirable to have no tape weight.

[0023]

Next, the present invention will be specifically described by way of examples, but the present invention is not limited to the following examples. In the following examples, the following were used as the adhesive and the double-sided pressure-sensitive adhesive tape. Adhesive: Isocyanate adhesive Double-sided adhesive tape: Double-sided tape using acrylic adhesive

Example 1 A lightweight FRP used as a shaft for a golf club
The hollow shaft made was manufactured by the following procedure. As shown in FIG. 2, the starting end 6 of the prepreg 4 having a resin content of 25 to 27% by weight was attached to the mandrel 2 with an adhesive or a double-sided adhesive tape 8. In this case, as shown in FIG. 3, an adhesive or a double-sided adhesive tape 8 is applied on the mandrel 2 along the axial direction.
Was applied or affixed, and the inner surface of the starting end 6 of the prepreg 4 was adhered to the adhesive or the double-sided adhesive tape 8. The length of the adhesive and the length of the tape were approximately equal to the length of the prepreg 4. In addition, the terminal portion 12 of the prepreg 4
An adhesive or a double-sided pressure-sensitive adhesive tape 14 was applied or stuck to the inner surface of the substrate, and when the winding was completed, the terminal portion 12 was attached to the prepreg existing inside to prevent the terminal portion 12 from rising. After the prepreg 4 was wound around the mandrel 2 and the prepreg 4 was cured, the mandrel 2 was extracted from the molded product to obtain an FRP hollow shaft.

Example 2 A lightweight FRP used as a golf club shaft
The hollow shaft made was manufactured by the following procedure. In this example, 2
The prepregs were stacked and wound simultaneously around the mandrel. As shown in FIG. 4, the starting end 6 of the prepreg 4 having a resin content of 25 to 27% by weight is
To mandrel 2. The mounting procedure was the same as in Example 1 (see FIG. 3). Further, on the outer surface of the starting end 6 of the prepreg 4, the starting end 18 of another prepreg 16 having a resin content of 25 to 27% by weight is coated with an adhesive or a double-sided adhesive tape 2.
0 attached. Further, an adhesive or a double-sided adhesive tape 24 is applied or stuck to the inner surface of the terminal portion 22 of the outer prepreg 16 so that the terminal portion 22 adheres to the prepreg existing inside when the winding is completed, thereby preventing the terminal portion 22 from rising. did. The attachment of the outer prepreg 16 to the inner prepreg 4 was performed before the attachment of the inner prepreg 4 to the mandrel 2, but may be performed after the attachment. After the prepregs 4 and 16 were wound around the mandrel 2 together and the prepregs 4 and 16 were cured, the mandrel 2 was extracted from the molded product to obtain an FRP hollow shaft.

The production method of Examples 1 and 2 is capable of easily and inexpensively attaching the starting end of a prepreg having a resin content of 25 to 27% by weight having poor surface tackiness to a mandrel, and at the time of completion of winding. Since it is possible to prevent the end portion from rising, it is possible to remarkably facilitate the winding of the prepreg around the mandrel, and thus greatly contribute to the improvement of the productivity of the lightweight shaft for golf clubs and the ultra-lightweight shaft, and the reduction of the manufacturing cost. there were.

[0027]

According to the present invention, the resin content is low, and the resin content having low surface tackiness is not more than 30% by weight, especially 2%.
When manufacturing an FRP hollow shaft by a sheet wrapping method using a prepreg of 7% by weight or less, the starting end of the prepreg can be easily and inexpensively attached to the mandrel, so that the prepreg can be easily wound around the mandrel. Therefore, it is possible to improve the productivity and reduce the production cost of a lightweight and ultra-light shaft by reducing the cost, and to maintain the high productivity without being affected by the resin content of the prepreg.

[Brief description of the drawings]

FIG. 1 (A) is a side view showing a state in which the starting end of a prepreg is attached to a mandrel using an adhesive or a double-sided adhesive tape, and FIG. 1 (B) is a diagram showing the starting end of the prepreg attached to a mandrel using a single-sided adhesive tape. It is a side view showing the state where it fell.

FIG. 2 is a side view showing a state where the starting end of the prepreg is attached to a mandrel using an adhesive or a double-sided adhesive tape in Example 1.

FIG. 3 is a front view showing a state in which an adhesive or a double-sided pressure-sensitive adhesive tape is applied or adhered to a mandrel and a prepreg end in Example 1.

FIG. 4 is a side view showing a state where the starting end of the prepreg is attached to a mandrel using an adhesive or a double-sided adhesive tape in Example 2.

[Explanation of symbols]

 2 Mandrel 4 Pre-preg 6 Start end of prepreg 8 Adhesive or double-sided adhesive tape 10 Single-sided adhesive tape

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ identification code FI // B29L 23:00 (58) Investigated field (Int.Cl. ⁷ , DB name) B29C 70/06

Claims (3)

(57) [Claims] 1. A prepreg having a resin content of 30% by weight or less is wound around a mandrel, and when the prepreg is cured to obtain a hollow shaft made of FRP, before the prepreg is wound around the mandrel, the starting end of the prepreg is bonded with an adhesive or A method of manufacturing a hollow shaft made of FRP, comprising attaching the prepreg to a mandrel with an adhesive tape, and then winding the prepreg around the mandrel. 2. A prepreg having a resin content of 30% by weight or less.
After wrapping around the mandrel, cure this prepreg
To obtain the FRP hollow shaft
Before winding the prepreg, apply a double-sided adhesive
Attach it to the mandrel with adhesive tape and then
Wrap the leg around the mandrel and shape the shaft
The tape is later peeled from the inner wall of the shaft.
Of manufacturing a hollow shaft made of FRP. 3. A prepreg having a resin content of 30% by weight or less.
After wrapping around the mandrel, cure this prepreg
To obtain the FRP hollow shaft
Before the prepreg is wound, the starting end of the prepreg is hardened.
Attached to the mandrel with the adhesive to which the catalyst was added,
Then, the prepreg is wound around a mandrel.
A method for manufacturing a hollow shaft made of FRP.