JPH06121852A - Productin of golf clubshaft - Google Patents

Abstract

PURPOSE:To provide a producting method of a golf clubshaft having a better production efficiency in comparison with one produced by a conventional inner pressure molding method or one of inner pressure holding tube. CONSTITUTION:This method is composed of a melting process of vinyl chloride resin with a plasticizer, a process in which molton fluid is conducted to the surface of a hollow mandrel 1 having air exhaust hole 11 and a vinyl chloride film 2 is formed, a process in which a prepreg 3 is wound up on the vinyl chloride resin film, a setting process of the rolled article to a molding frame 4, and a heating and molding process by injecting air from the hollow made in the mandrel 1.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for manufacturing a golf club shaft, and more particularly to a method for easily manufacturing a golf club shaft by an internal pressure molding method.

[0002]

2. Description of the Related Art In the internal pressure molding method, as shown in FIG. 1, a hollow mandrel 1 having a taper is covered with a release layer 2 for easy release, and the release layer 2 is covered with a prepreg 3. The mandrel 1 is wound and set in the molding die 4, and air is blown into the hollow portion of the mandrel 1 to form the mandrel 1.
In this method, the prepreg 3 is subjected to internal pressure by ejecting air from the air discharge hole 11 penetrating into the hollow portion, and is heat-molded. At this time, since an external pressure is applied from the molding die 4, there is an advantage that a shaft having a smooth surface can be molded.

When a golf club shaft is manufactured by such an internal pressure molding method, a conventional release layer 2 covered with a rubber tube having a shape conforming to the taper of the mandrel 1, or a narrow nylon bag without taper. Was covered on the mandrel 1 and wound according to the taper of the mandrel 1 so that a layer was formed on the surface of the mandrel 1.

However, when a rubber tube is used, the rubber tube must be manufactured in a shape corresponding to the mandrel. Alternatively, the mandrel must be dipped in latex, dried and vulcanized to be provided. For this reason, there are drawbacks that two mandrels are required for one process, vulcanization of latex is required, and the cost of the tube is high. There is also a drawback that the mandrel easily rusts.

In the case of covering with the elongated nylon bag, after inserting the mandrel into the nylon bag,
It was necessary to wrap the extra space of this nylon bag on the surface of the mandrel. Therefore, the efficiency is poor, and there is a possibility that the shaft may be wrinkled.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a method for manufacturing a golf club shaft, which has better working efficiency than the conventional internal pressure molding method or internal pressure holding tube. .

[0007]

In order to solve the above problems, the golf club shaft manufacturing method according to the present invention comprises:
A step of melting a vinyl chloride resin and a plasticizer, a step of providing the melt on the surface of a mandrel having a hollow and air discharge hole to form a vinyl chloride resin coating, and a step of winding a prepreg on the vinyl chloride resin coating. The method is characterized by including a step of setting the wound article in a molding die, and a step of injecting air from a hollow portion formed in the mandrel and performing heat molding.

According to the present invention, since the release layer is formed by using the vinyl chloride resin coating, it is not necessary to carry out vulcanization as in the case of using a rubber tube, and unlike the case of using a nylon bag. It is not necessary to wind the extra part along the mandrel. Therefore, there is an advantage that workability is significantly improved. Furthermore, tube molding and shaft molding can be performed with the same mandrel, and the mandrel does not rust. There is also an advantage that the cost of the release layer is low.

[0009]

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, a vinyl chloride resin and a plasticizer are melted while heating, stirring and defoaming to produce a melt.

The vinyl chloride resin / plasticizer melt is preferably produced in an inert gas atmosphere such as nitrogen gas. This is to prevent oxidation, dehydrochlorination, and dissociation (cutting) due to oxygen in the air.

Further, it is preferable that the melt is produced under pressure. Pressurization helps the plasticizer penetrate into the vinyl chloride resin and accelerates melting.

This pressurization is preferably 1-3 kg / cm ^2.
It should be When it is less than 1 kg / cm ^2, it takes a long time to melt, while when it exceeds 3 kg / cm ² , it becomes difficult to manage the equipment.

The plasticizer added to the vinyl chloride resin as described above is added to weaken the van der Waals force between the vinyl chloride resin molecules and to impart fluidity to the resin.
The amount added is 1 for 100 parts by weight of vinyl chloride resin.
It is preferably 60 to 220 parts by weight. If it is less than 160 parts by weight, melting is difficult, while if it exceeds 220 parts by weight, the film forming strength is weak and stickiness increases.

Examples of such plasticizers include DO
One or more of A, DOS, DOB, TCP, etc. can be used.

When the above-mentioned vinyl chloride resin / plasticizer is melted, it is preferably melted at a temperature of 150 to 180 ° C. If it is lower than 150 ° C, it may not be melted sufficiently, while if it is higher than 180 ° C, the vinyl chloride resin may be attached / detached or infusibilized due to oxidation, dehydrochlorination or dissociation.

After forming the melt in this way, the air discharge hole of the mandrel is temporarily sealed with tape or the like to have a hollow portion, and the melt is formed on the surface of the mandrel having the air discharge hole in the hollow portion. To form a vinyl chloride resin film. The method of forming this vinyl chloride resin coating is not basically limited in the present invention. For example, it can be formed by dipping a mandrel in the melt and pulling it up (dip method). Use a spraying method in which the melt is sprayed while keeping it warm, or a method of applying iron while keeping the melt warm. You can

When the dipping method is adopted, the mandrel is immersed in the melt and pulled up. At this time, a mold release agent may be provided on the surface of the mandrel to further improve the mold release property. it can.

Further, it is preferable that the mandrel is pulled up from the melt and then air-cooled to form a vinyl chloride resin film on the surface of the mandrel.

The viscosity of such a melt is preferably 20 to
It should be 100 poise. If it is less than 20 poise, the vinyl chloride resin may not sufficiently adhere to the surface of the mandrel when immersed in the melt, while if it exceeds 100 poise, the vinyl chloride resin film formed may be uneven. Is.

The thickness of the vinyl chloride resin coating as described above is preferably 0.4 to 1.5 mm. 0.4 mm
If it is less than the above range, the film strength is insufficient and scratches may occur during processing. Further, when it exceeds 1.5 mm, it takes too much time and is not practical.

A prepreg is wound around the vinyl chloride resin coating thus formed, set in a molding die, air is supplied from the hollow portion of the mandrel 1, and this air is jetted from the air discharge hole 11. The prepreg is heat-molded while applying an internal pressure. The prepreg used at this time may be one in which reinforcing fibers are impregnated with a resin and heated to be in a semi-cured state, or one in which the reinforcing fibers are simply impregnated with a resin and not heated can be used.

[0022]

[Example] 190 parts by weight of DOA as a plasticizer was mixed with 100 parts by weight of vinyl chloride resin, and the mixture was placed in a nitrogen gas atmosphere for 1 k.
Under a pressure of g / cm ² , the mixture was stirred at 170 ° C. and melted while defoaming to form a melt. The viscosity of this melt was 30 poise.

In this nitrogen gas atmosphere, the mandrel was immersed in the melt, pulled up, and air-cooled to form a vinyl chloride resin coating on the mandrel surface. The thickness of the vinyl chloride resin coating was 0.5 mm.

A prepreg was wound around this in the same manner as in the prior art, set in a mold, and air was blown from the hollow portion of the mandrel to perform hot molding.

As a comparison, using a nylon tube, a golf club shaft manufactured in the same manner was manufactured, and the results of measuring uneven thickness, ring fracture and 3-point bending strength are shown in Table 1.

Table 1 Examples Comparative Examples Uneven thickness (mm) 0.05 0.15 (max) Ring crush (kg / 5 mm) 30 20 Three-point bending fracture (kg) 76 65

[0027]

As described above, according to the method for manufacturing the golf club shaft of the present invention, the melt of vinyl chloride resin / plasticizer is used to form the vinyl chloride resin coating, and the rubber tube is used. There is no need to perform vulcanization as in the case of using, and it is not necessary to wind the extra portion along the mandrel as in the case of using a nylon bag. Therefore, there is an advantage that workability is significantly improved. Furthermore, tube molding and shaft molding can be performed with the same mandrel, and the mandrel does not rust. There is also an advantage that the cost of the release layer is low. That is, there is an advantage that the golf club shaft can be manufactured significantly more efficiently than the conventional one. Further, there is an advantage that a golf club shaft having less uneven thickness and good strength can be manufactured as compared with the conventional one.

[Brief description of drawings]

FIG. 1 is a sectional view for explaining a method for manufacturing a golf club shaft by an internal pressure molding method.

[Explanation of symbols]

 1 Mandrel 11 Air exhaust hole 2 Release layer 3 Prepreg 4 Mold

Claims (4)

[Claims] 1. A step of melting a vinyl chloride resin and a plasticizer, a step of forming the vinyl chloride resin film by providing the melt on a mandrel surface having a hollow portion and an air discharge hole in the hollow portion, A step of rolling a prepreg on the vinyl chloride resin coating, a step of setting the rolled material in a mold, a step of injecting air from a hollow portion formed in the mandrel, and heat molding. Of manufacturing a golf club shaft. 2. The method for manufacturing a golf club shaft according to claim 1, wherein the vinyl chloride resin and the plasticizer are melted in an inert gas atmosphere. 3. The method of manufacturing a golf club shaft according to claim 1, wherein the vinyl chloride resin and the plasticizer are melted under pressure. 4. The vinyl chloride resin film is formed by immersing a mandrel in a melt and pulling it up, and the dipping and pulling up in the melt is carried out in an inert gas atmosphere. 5. A method for manufacturing a golf club shaft according to any one of 3 to 3.