JPH04261680A - Club head for golf and manufacture of the same - Google Patents

Abstract

PURPOSE:To provide a head for golf excellent in strength, vibrational property and antiwear property and stable time dependent property. CONSTITUTION:A head for golf has at least a shell strength layer molded with a material capable of forming urethane modified acrylic resin with continuous fibers as reinforcing fibers according to a RIM molding method.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a fiber-reinforced resin golf head and its manufacturing method.

0002

[Prior Art] Conventionally, golf heads (hereinafter referred to as heads) made of fiber-reinforced resin have been developed in Japanese Patent Application Laid-Open No. 58-18
Fabrics made of continuous fibers, as seen in No. 5175,
An outer shell molding material in which rovings, blades, etc. are impregnated with a thermosetting resin is placed in a mold having a head shape together with a core material made of a meltable material or a foamed synthetic resin,
For materials that can be melted by hardening the resin by applying pressure and heating, the core material is melted and removed by heating after molding and molded into the desired head shape, and JP-A-58-2
As seen in No. 12465, it is known that after a core material is fixed in a mold for forming a head, a fiber-reinforced resin is injected into the pressed mold to form a desired head. The conventional golf head described above has the following drawbacks. In other words, heads made of thermosetting resins such as epoxy resins reinforced with continuous fibers can produce strong and rigid heads, but on the other hand, they tend to chip easily and do not have good wear resistance. When molding the head, reinforcing fibers may become disordered, resulting in a decrease in strength, and there may be many voids on the surface or inside, which requires time and effort in post-processing.
There were drawbacks such as the strength being lower than the designed strength.

[0003] In addition, in terms of manufacturing, the process of molding the prepreg, laminating the prepreg onto the core material, and placing the molded resin material in the head-shaped mold is quite complicated and time-consuming; The heat curing time when molding with a mold is approximately 20 to 40 minutes at approximately 100°C to 150°C, and the molding cycle is relatively long, and the fibers are easily disturbed by the flow of resin during molding, and the molding process during that time is relatively long. In mass production, it is necessary to maintain the temperature at an appropriate temperature.
The manufacturing cost is high due to the necessity of using a large number of molds.

[0004] In addition, in the latter injection molded head made of synthetic resin reinforced with short fibers, when thermoplastic resin is used as the synthetic resin, short fibers are used as the reinforcing material, so continuous The disadvantage is that the head strength and rigidity are inferior to those using fibers, and since these heads are molded by injection molding, the molding pressure is high, so it is difficult to withstand high pressure. This required strong molds, etc., resulting in high equipment costs. Therefore, in order to eliminate the above-mentioned drawbacks, the present inventors invented a head formed by RIM molding, in which the cured resin material is nylon, crosslinked polyesteramide, or crosslinked polyaminoamide, and a method for manufacturing the same.

[0005]

Problems to be Solved by the Invention The head formed by the conventional RIM molding method has the following problems. In the head and its manufacturing method using RIM molding where the resin cured product is nylon, due to the characteristics of the material, the viscosity of the raw material is high, so it is difficult for the resin to wrap around inside the mold. Since it was difficult to impregnate the fibers sufficiently, there was a problem in terms of strength. Additionally, there were problems with low dimensional stability and strength due to moisture absorption. Other problems include the low heat distortion temperature, which makes it difficult to maintain properties in a car under the hot sun or under direct sunlight, and the inability to simultaneously satisfy the required characteristics of bending elasticity and impact strength. In the head and its manufacturing method by RIM molding in which the cured product is a crosslinked polyesteramide resin or a crosslinked polyaminoamide resin, the molding material is solid at room temperature.
In order to melt the molding material, keep its viscosity low, and sufficiently impregnate the reinforcing fibers, it was necessary to heat and melt the molding material to a temperature of 120°C or higher and to maintain the mold at a temperature of 100°C or higher.

Therefore, since the temperature during molding is high, if a foam is used as the core material, the foam will soften due to pressure and heating during molding, and the molding resin will be impregnated inside, causing the outside of the head to deteriorate. The drawbacks were that the thickness of the shell was uneven, the foam shrunk, and the weight increased. For this purpose, it was considered to use a low melting point alloy for the core material, but the work to remove the low melting point alloy after hardening and forming was done at high temperatures, which involved risks such as burns, and the loss of alloy. The large size led to an increase in costs.

[0007]

SUMMARY OF THE INVENTION In view of the above-mentioned conventional drawbacks, the present invention aims to provide a head that is excellent in strength, vibration characteristics, and wear resistance, and has stable characteristics over time. The present invention is a golf head and a method for manufacturing the same, characterized in that the outer shell strength layer of the head body is molded by RIM molding using a material capable of producing urethane-modified acrylic resin. Although the head of the present invention can be molded using the resin alone, various reinforcing fibers such as glass fiber, carbon fiber, ceramic fiber, boron fiber, tungsten fiber, molybdenum fiber, steel fiber, beryllium fiber, and stainless steel fiber can be used. Inorganic fibers such as fibers, synthetic organic fibers such as polyamide fibers, polyester fibers, aramid fibers, etc. can also be used as reinforcing materials. The above-mentioned reinforcing fibers are processed into products such as mats, woven fabrics, braids, and rovings, and these can be used alone or in combination. The fiber content in this case can be arbitrarily selected depending on the viscosity of the resin, the type of reinforcing fiber, and the characteristics of the designed head, but it is usually about 5 to 80% by weight, preferably 10 to 70% by weight. It is about %.

[0008] The method for molding the golf head of the present invention includes forming a core body having a substantially head shape, and adding continuous fibers or reinforcing fibers made of the continuous fibers in the shape of woven fabric, roving, mat, braid, etc. to the core body. A molded body is formed by coating or laminating them singly or in combination. Then, the molded body is placed in a predetermined position in a head molding mold, and after the mold is closed, a material capable of producing a urethane-modified acrylic resin is injected into the mold, and the material is reacted and cured in the mold. This is a method of molding the head. The location where the reinforcing fibers are placed can be changed depending on the designed weight of the head, the stiffness, strength, design, etc. of the face and other parts. The core material may be a foam made of acrylic resin, urethane resin, epoxy resin, or the like, or a lightweight hollow balloon may be mixed into the resin and molded. Also, it does not foam at room temperature,
It is also possible to mix and mold materials that foam when heated. Although the core material can be directly coated and laminated with reinforcing fibers, a tube or a resin layer may be provided on the surface of the core material.

[0009]

[Function] As described above, the head of the present invention uses the RIM molding method to obtain a urethane-modified acrylic resin molding, so the viscosity of the molding material is lower than that of conventional epoxy resins, nylon resins, etc. Therefore, even if continuous fibers are used as reinforcing fibers, the material can easily go around between the reinforcing fibers, making it easy to impregnate the product. The weight can be reduced. Further, the reinforcing fibers may be in the form of woven fabric, mat, roving, biaxial or triaxial blades, and shapes depending on the required characteristics. In addition, molding pressure,
Since the molding temperature can be lowered, the heat resistance temperature of the core material is not limited, and a material that is lightweight and easy to handle in molding can be selected.

0010

[Example] An example will be explained based on the drawings. FIG. 1 is an external view of the golf head of the present invention, and FIG. 2 is an explanatory view of one manufacturing step. That is, the head 1 uses a urethane-modified acrylic resin as the cured resin, a continuous fiber such as glass fiber or carbon fiber as the reinforcing fiber 6, and is formed into the shape of a mat, braid, woven cloth, etc., and as the core material 7, Acrylic resin foam was used. Moreover, the score line 4 of the face part and the shaft insertion hole 3 of the neck part 2 were formed at the same time as the head was molded.

[0011] In the head molding method of the present invention, a substantially head-shaped core material 7 is formed of a foam, reinforcing fibers 6 made of continuous fibers are applied to the core material, and a matte shape is formed on the thick part of the core material. The layer had a blade shape and the face part had a woven fabric shape, and the layers were coated and laminated to form a molded body with a fiber content of 10 to 50% by weight. The molded body formed as described above was placed in a mold 8 for forming the head, and a mandrel 5 for forming the shaft insertion hole 3 was placed in the neck portion 2. After the mold is pressed, a material capable of producing urethane-modified acrylic resin is injected into the gap between the mold and the core material using a two-component injection machine, and the material is reacted and cured within the mold to form the material. R.I.
This is a method of integrally molding the head 1 using the M molding method. At this time, a protrusion for forming the score line is provided on the mold around the face part. In addition, when using the above core material, the foam can be used as it is, but the surface of the foam can be covered with a tube of nylon, cellophane, polyethylene, etc., or coated with resin. By forming a resin layer, it is possible to prevent the molding material from penetrating the foam, and a lightweight head with uniform thickness can be obtained.

0012

The present invention provides a head configured as described above and a method for manufacturing the same, and thus provides the following effects. In other words, the head of the present invention can be molded by arranging woven fabrics, rovings, mats, braids, etc. made of continuous fibers as reinforcing fibers at locations according to the required characteristics of the head, so that bending strength, compressive strength, etc. The thickness of the entire head shell can be made thinner. Therefore, the degree of freedom in design is improved, such as making the head shape larger than before or making the club lighter. In addition, according to the molding method of the present invention, a material with low viscosity that can produce urethane-modified acrylic resin is injected into the mold and reacted and cured in the mold, so wetting with the fibers is good and the material is Even if the content is high, it will satisfactorily impregnate the fibers. Furthermore, since it can be molded at room temperature, foams such as acrylic resin, urethane resin, and epoxy resin can be used as the core material, making it easy to mold the core material and simplifying the process. , can be manufactured at low cost.

[Brief explanation of the drawing]

FIG. 1 is an external view of a golf head of the present invention.

FIG. 2 is an explanatory diagram of one manufacturing process of the golf head of the present invention.

[Explanation of sign]

1 Head 2 Neck part 3 Shaft insertion hole 4 Score line 5 Mandrel 6 Reinforcement fiber 7 Core material 8 Mold

Claims (2)

[Claims] 1. A golf head having an outer strength layer formed of a fiber-reinforced resin material, wherein the outer strength layer is formed by RIM molding of a material capable of producing a urethane-modified acrylic resin using continuous fibers as reinforcing fibers. A golf head characterized by: 2. Forming a substantially head-shaped core, covering and laminating the core with reinforcing fibers made of continuous fibers to form a molded body, and placing the molded body in a mold for forming the head; A method for manufacturing a golf head, comprising injecting a material capable of producing a urethane-modified acrylic resin into the gap between the core body and a mold, and molding the golf head by reacting and curing the material in the mold.