JPH082382B2 - Golf club head manufacturing method - 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 for manufacturing a golf club head made of synthetic resin.

[0002]

2. Description of the Related Art Of golf clubs, wood, spoon,
The heads of Buffy, Creek, etc. were originally made of wood such as Persimmon, but recently, those made of metal or synthetic resin have become popular.

Particularly recently, as a synthetic resin head,
Attention has been focused on a lightweight core material that is used as an insert and a main body is provided around it by injection molding. This head is
This is because the inside of the main body is lightweight and the entire head can be enlarged.

In this type of head, a foam or sponge made of a resin such as polyurethane, ABS resin, polycarbonate, nylon, and impact-resistant polystyrene is used as a lightweight core material. In this case, in order to reduce the weight of the core material as much as possible and to enlarge the entire head, the conditions at the time of foam molding were devised to form a cavity in the center of the obtained foam or hollow out the foam. It is also possible to provide a cavity inside. As the material of the main body, various thermoplastic resins or thermosetting resins mixed with reinforcing fibers such as carbon fibers are used.

[0005]

The use of a uniform foam as a lightweight core material has a limit in reducing the weight of the core material because it has to withstand the pressure during injection molding for forming the main body. There is a limit to the thinning and uniforming of the thickness of the main body side, and as a result, there is naturally a limit to the enlargement of the entire head.

[0006] The method of forming a cavity in the center of a foam body can further reduce the weight of the lightweight core material, but due to a slight difference in the conditions during foam molding, the cavity forming position may be biased. Often, the shape of the cavities is not constant, and as a result, the sweet spot may be different depending on the club. The method of hollowing out the foam and providing the cavity inside has the disadvantages that the quality is not constant and the cost is high because it is a manual work. Also, in any of these methods, there is essentially the above-described problem (limitation of thinning or uniformization) due to the use of a foam as a lightweight core material.

In view of such a situation, the present invention is a method completely different from the method using a lightweight core material made of foam,
It is an object of the present invention to provide a method for manufacturing a golf club head made of synthetic resin, which is commonly called a decahead.

[0008]

In the method of manufacturing a golf club head of the present invention, urea and a water-soluble polymer are the main ingredients.
After making a uniform solid composition, crush it,
The process of making powder of appropriate particle size, compression molding or
A step of injection-molding to obtain a prototype of a desired shape, using this prototype as a core material (1), and using the core material (1) as an insert to inject a synthetic resin around the injection-molded body
In which the step of producing (2), then the core material (1) characterized by comprising the step eluted with water.

The present invention will be described in detail below.

In the present invention, a powder which is a pulverized product of a uniform solid composition containing urea and a water-soluble polymer as main components.
The master obtained by molding the body is used as the core material (1). A typical example of the water-soluble polymer is polyvinyl alcohol. Core material
(1) can be manufactured as follows.

That is, when urea and water-soluble polymer powder or granules are mixed and heated, the urea melts,
When stirring is performed, the water-soluble polymer dissolves in the melted urea. At this time, water may be added. It is then cooled and ground to the appropriate particle size. Alternatively, after uniformly mixing the aqueous solution of urea and the aqueous solution of the water-soluble polymer,
It is dried and pulverized until the water content becomes about 2% by weight or less. The powder thus obtained is compressed or injected.
The core material (1) is formed by molding and has a characteristic that molding shrinkage hardly occurs at this time. As molding conditions, for example, a temperature of 90 to 125 ° C. and a pressure of 200 kg / cm ²
More than some conditions are adopted.

Using the above core material (1) as an insert,
When injection molding is performed by injecting a synthetic resin around it, an injection molding body (2) is formed. As synthetic resin for this purpose,
A molding resin such as ABS resin, polycarbonate, nylon, or polyether ether ketone (a thermoplastic resin is often used, but a thermosetting resin is sometimes used) is used, and two or more kinds of resins are used. It can also be blended and used as a polymer alloy. At this time, it is desirable to mix an appropriate amount of reinforcing fibers such as carbon fibers, aromatic amide fibers, boron fibers, glass fibers, titanium fibers and whiskers in the molding resin, and other various fillers, Coloring agents, stabilizers, plasticizers, and other additives may be added as appropriate.

The obtained injection-molded product has an injection-molded body (2).
It has a configuration in which the core material (1) is included in the hollow part of the. Core material (1)
Since it is easily eluted by water heated at room temperature or heated, the core material (1) can be removed from the hollow portion of the injection-molded body (2).

In the hollow portion of the head thus obtained,
If desired, a lightweight filling can be filled. As an example, polyurethane can be blown into the hollow portion for high foaming.

The head is polished or painted as needed, and further, necessary parts and shafts are attached to form a club.

The golf club head of the present invention can be used as a head for wood, spoon, buffy, creek and the like.

[0017]

According to the method of the present invention , a powder, which is a pulverized product of a uniform solid composition containing urea and a water-soluble polymer as main components , is pressed.
Temporary core material obtained by compression molding or injection molding (1)
The core material (1) is hard and firm unlike the conventional lightweight core material made of foam, and since the core material (1) hardly causes molding shrinkage during molding, the core material (1) is Injection molded body (2) with material (1) as insert
Can be injected at high pressure. Therefore, the injection-molded body (2) can be made thinner, and the volume of the hollow portion can be increased accordingly. In addition, the injection-molded body (2) can be made to have a uniform thickness, and the degree of freedom in designing the head is significantly greater than in the past.

In addition, the manufacturing of the core material (1) and the elution of the core material (1) after forming the injection-molded body (2) are easy, and the manufacturing process is not complicated.

[0019]

EXAMPLES The present invention will be further described with reference to examples. Hereinafter, "parts" refers to parts by weight.

Example 1 FIG. 1 is an explanatory view schematically showing the manufacturing method of the present invention.

90 parts of urea powder and 5 parts of polyvinyl alcohol powder were mixed and heated to 135 ° C. When urea was melted, stirring was carried out while maintaining this temperature to dissolve polyvinyl alcohol in the molten urea. . This was left to cool and solidify, and then crushed with a crusher. The obtained powder is supplied to an injection molding machine and the temperature is 120 ° C. and the injection pressure is 20.
Injection molding was carried out under conditions of 0 to 300 kg / cm ² , mold temperature of 20 to 80 ° C. and molding cycle of 150 seconds to obtain a core material (1) with a mold core pin (3) for fixation. This state is shown in (a) of Fig. 1.
Is.

Next, the core material (1) with the fixing mold core pin (3) was set as an insert in an injection molding machine, and ABS resin mixed with carbon fiber short fibers was supplied to the injection molding machine. Then, injection molding was carried out under the conditions of a resin temperature of 230 ° C., an injection pressure of 700 kg / cm ² , a mold temperature of 40 ° C. and a molding cycle of 80 seconds to form an injection molding body (2). This state is shown in FIG.

When hot water was sprayed on the core material (1) portion of the molded product obtained above, the core material (1) was easily eluted from the injection molding body (2) as shown in FIG. After the core material (1) was removed, the injection-molded body (2) was painted.

The head thus obtained is an injection-molded head generally called a conventional deca-head (a foam resin core material made of ABS resin having a cavity inside and a main body made of carbon fiber mixed ABS resin). It was one size larger than the same weight. The necessary parts and shaft were attached to this head to make a product club. Note that polyurethane may be blown into the hollow portion of the injection-molded body (2) to foam it.

[0025]

According to the method of the present invention, the injection molded body
Since it is possible to reduce the thickness and make the thickness uniform in (2), the size can be further increased as compared with the conventional head, and the degree of freedom in the design of the head is increased.

In addition, there are advantages that the manufacturing process does not become complicated and that a head of constant quality can be manufactured at all times, so that the sweet spot does not shift depending on the product.

Therefore, the golf club head manufactured by the method of the present invention can meet the requirements of the times in terms of performance and design / appearance.

[Brief description of drawings]

FIG. 1 is an explanatory view schematically showing the production method of the present invention.

[Explanation of symbols]

 (1)… Core material, (2)… Injection molding body, (3)… Fixing mold core pin

Claims (1)

[Claims] 1. A homogeneous composition containing urea and a water-soluble polymer as main components.
After making a solid composition , crush it
The process of forming powder with a particle size, and compressing or injection molding this powder to obtain the desired shape.
A step of forming a mold, a step of manufacturing an injection-molded body (2) by using this prototype as a core material (1) and injecting a synthetic resin around the core material (1) as an insert , and then the core material A method for manufacturing a golf club head, which comprises the step of eluting (1) with water.