JPH04221579A - Manufacture of metal wood golf club head - Google Patents

Abstract

PURPOSE:To offer a metal wood golf club head which extends a flying distance and at the same time reduces an unpleasant metallic struck ball sound and also whose formation work is facilitated, by filling under a uniform foaming condition a predetermined quantity of filling material into a metal head hollow portion. CONSTITUTION:A filler consisting of micro capsule foaming beads whose main material is a vinylidene chloride polymer in which a volatile fluid is contained, is filled into a metal head main body hollow portion within the range of 0.05g/ cm<3>-0.15g/cm<3>, preferably 0.07g/cm<3>-0.13g/cm<3> at the bulk specific gravity of a foamed body after thermal foaming, and then, the above foaming beads together with the metal head main body are heated at 120 deg.C for 30 minutes, and foaming beads are foamed, and the metal head main body hollow portion is filled uniformly with foamed beads.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a method of manufacturing a metal wood golf club head, and more specifically, the present invention relates to a method for manufacturing a metal wood golf club head, and more specifically, the present invention relates to a method for manufacturing a metal wood golf club head, and more specifically, a metal wood golf club head in which the hollow portion of the metal head body is filled with microcapsule-shaped foamed beads in a uniformly foamed state. The present invention relates to a method of manufacturing a golf club head.

0002

[Prior Art] Conventionally, it is known that metal wood golf club heads have their center filled with hard polyurethane foam injected and foamed in order to improve the feeling when hitting the ball, including the sound of the ball. . In addition, wood golf club heads made mainly of fiber-reinforced plastic contain gas generating agents that generate gas when heated above a certain temperature, as disclosed in Japanese Patent Laid-Open No. 59-91975, for example. After forming a coating layer by mixing carbon fibers into the core material and adhering them to the outer periphery of this core material using a thermosetting resin, the coating layer is heated and cured in a mold, and the heat of the molding causes gas to be removed. It has also been proposed that a club head is molded by generating gas from a generating agent and pressurizing and compressing a coating layer onto the inner surface of a mold from the direction of the core material, thereby preventing the formation of voids between the prepreg materials.

0003

[Problems to be Solved by the Invention] However, with the method of injecting and foaming rigid polyurethane foam into the hollow part of the metal head, it is difficult to fill the hollow part in a uniformly foamed state, resulting in so-called "polluting". There are also problems in that the hard polyurethane foam filled in the ball collapses when the ball is hit, creating voids inside. In addition, it is stated that the latter wood golf club head, which is mainly made of fiber-reinforced plastic, compresses the coating layer under pressure using the gas pressure of the gas generating agent mixed in the core material, but in reality, Since the molding pressure for the club head is low, it is difficult to provide sufficient strength necessary for the club head, and therefore, this molding method is considered to be impractical.

0004

[Purpose of the Invention] This invention was devised in view of the above-mentioned problems in the prior art, and aims to extend the flight distance by filling the hollow part of the metal head with a predetermined amount of filler in a uniformly foamed state. It is an object of the present invention to provide a method for manufacturing a metal wood golf club head that can reduce unpleasant metal hitting sounds and facilitate molding work.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present invention forms a metal head body in a hollow shape, and fills the hollow portion of the metal head body with a filling material made of microcapsule-shaped foam beads. The bulk specific gravity of the foam after foaming is 0.05g/cm3 to 0.15g/cm3
The purpose is to fill the area within the following range. Moreover, the gist of the present invention is to use, as the filler, foamable microcapsule beads whose main material is a vinylidene chloride polymer encapsulating a vaporizable fluid.

[0006]

Effect of the Invention The present invention is constructed as described above, and a filling material consisting of microcapsule foam beads mainly made of vinylidene chloride polymer containing a vaporizable fluid is provided in the hollow part of the metal head body. The bulk specific gravity of the foam after heating and foaming is 0.05 g/cm3 to 0.15 g/cm3.
, preferably 0.07g/cm3 to 0.13g/cm3
cm3, and then heat the expandable beads together with the metal head body at 120°C for 30 minutes to foam the expandable beads, so that the inside of the hollow part of the metal head body is uniformly filled with the expandable beads. It is possible to fill the ball with the ball and expect the highest ball flight, and at the same time, it is also possible to reduce the metallic sound that is unique to metal heads when hitting the ball, and furthermore, the molding work can be performed easily. It is something.

[0007] Here, as the vaporizable fluid, propane,
Examples include n-butane, isobutane, n-pentane, isopetane, etc., but isobutane is preferable depending on boiling point and the like. Examples of vinylidene chloride polymers include homopolymers of vinylidene chloride, and copolymers of vinylidene chloride, acrylonitrile, methacrylonitrile, and the like. Among these, a copolymer of vinylidene chloride and acrylonitrile is preferred.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a front view of a metal wood golf club head embodying the present invention, and FIG.
A cross-sectional view taken along the X arrow is shown, and numeral 1 indicates a metal head main body made of a metal material, and numeral 2 indicates a filler made of foam beads uniformly filled into a hollow portion 3 of the metal head main body 1.

The filler 2 may be, for example, thermally expandable hollow microspheres (manufactured by Nippon Philite Co., Ltd.) that have a shell made of vinylidene chloride/acrylonitrile copolymer and encapsulate or encapsulate isobutane as a blowing agent. ...Product name: EXPANCEL) is used. The properties of these thermally expandable hollow microspheres are that the particle size (average) is 10μ before expansion and 40μ after expansion.
Particle size range is 5-30μ unexpanded and 10-10μ after expanded.
It becomes 0μ. In addition, the bulk specific gravity (g/cm3) is 0.7 before expansion and 0.02 or less after expansion, and the true specific gravity (
g/cm3) is 1.3 before expansion and 0.0 after expansion.
4 or less, making it extremely lightweight.

[0010] Furthermore, the expansion temperature is 80°C to 150°C.
It is ℃. Next, to explain the manufacturing method of a metal wood golf club head, first, a hollow portion 3 as shown in FIG.
A metal head body 1 is formed, and the hollow part 3 of the metal head body 1 is filled with foam beads of microcapsules mainly made of vinylidene chloride/acrylonitrile copolymer in which butane gas is sealed from the neck part 4. The filling amount of the filler 2 is set such that the bulk specific gravity of the foam after heating and foaming is 0.
It is filled in a range of 0.05 g/cm 3 to 0.15 g/cm 3 , preferably 0.07 g/cm 3 to 0.13 g/cm 3 .

After that, the filler material 2 and the metal head body 1 are heated at 120° C. for 30 minutes to foam the expandable beads and form the metal head body 1.
It is possible to uniformly foam and fill the hollow part 3 with the filler 2 made of expandable beads. As described above, by filling a predetermined amount of the filler 2 into the hollow portion 3 of the metal head body 1, the highest ball initial velocity efficiency (ball initial velocity/club head speed), that is, the highest ball initial velocity efficiency (ball initial velocity/club head speed), It is possible to expect high flight distance, reduce the unpleasant sound of metal hitting, and the molding work can be carried out efficiently in an extremely short period of time.

Next, as a result of experimenting with the initial velocity efficiency of the ball using the metal head body 1 constructed as described above, the results were as follows.
We were able to obtain results as shown in Figure 4. [Experiment conditions]
(a) Metal head: All club heads had the same weight and had a hollow body volume (75 ml). (b) Foam: Thermally expandable hollow microspheres containing and encapsulating isobutane (manufactured by Nippon Philite Co., Ltd.) Product name: EXPANCEL
) It was used. (c) Foaming conditions: Heating at 120°C for 30 minutes. (d) Initial velocity efficiency (initial velocity of ball/club head speed): A golf ball was hit at a head speed of 37 M/sec using a swing robot.

[0013] In Fig. 4, the initial velocity efficiency without the filler is set as 100, and each initial velocity efficiency is expressed as an index. [Experimental Results] As a result of conducting experiments under the above experimental conditions, the bulk specific gravity of the foam after heating and foaming was in the range of 0.05 g/cm3 to 0.15 g/cm3, preferably 0.07 g. /cm3 to 0.13g/
It was found that the initial velocity efficiency becomes high when it is filled within a cm3 range.

[0014]

Effects of the Invention The present invention provides a method for manufacturing a metal wood golf club head whose center is filled with a core material as described above, in which the metal head body is formed into a hollow shape, and the , the bulk density of the foam after foaming is 0.05 g/cm3 to 0.15 g/c.
Since it is filled within the range of m3, we can expect the highest initial velocity efficiency of the ball, that is, the highest ball flight.It also reduces the metal hitting sound that is unique to metal heads, making it similar to persimmon or carbon heads. This has the effect that sound can be obtained and the molding work can be carried out efficiently in an extremely short period of time.

[Brief explanation of the drawing]

FIG. 1 is a front view of a metal wood golf club head embodying the present invention.

FIG. 2 is a sectional view taken along the line XX in FIG. 1;

FIG. 3 is a cross-sectional view of inserting filler material into a club head.

FIG. 4 is a graph illustrating the results of an experiment on the initial velocity efficiency (expressed as an index) with respect to the bulk specific gravity of the foamed filler.

[Explanation of symbols]

1 Metal head body 2 Filling material made of expandable beads 3 Hollow part

Claims (2)

[Claims] 1. A method for manufacturing a metal wood golf club head in which the center portion is filled with a core material, wherein the metal head body is formed into a hollow shape, and microcapsule-shaped foam beads are placed in the hollow portion of the metal head body. The bulk density of the foam after foaming is 0.05g.
A method for manufacturing a metal wood golf club head, characterized in that the filling range is from 0.15 g/cm3 to 0.15 g/cm3. 2. The method for manufacturing a metal wood golf club head according to claim 1, wherein the filler is microcapsule foam beads mainly made of a vinylidene chloride polymer encapsulating a vaporizable fluid. .