JPH05228227A - Die for golf ball - Google Patents

Abstract

PURPOSE:To improve the mold releasing property of a die, improve durability, and manufacture a beautiful golf ball by impregnating fluorine macromolecule fine grains into many crack sections on a chrome-plated layer formed on the face to be brought into contact with a golf ball molding material. CONSTITUTION:A chrome-plated layer 6 is coated and formed on the surface of the whole inner face and its periphery of a recess section 3 to be brought into contact with a golf ball molding material M of a die 2 for vulcanization- molding a golf ball 1. Numerous crack sections 7 are naturally formed into a mesh shape on the chrome-plated layer 6, fluorine macromolecule fine grains 8 such as polytetrafluoroethylene are impregnated into the crack sections 7 to form a composite film W. The die 2 having excellent mold releasing property when the golf ball 1 is extracted after molding and excellent durability is obtained. No mold releasing agent is required for use, such trouble that small recesses are generated on the surface of the molded golf ball can be prevented, and a beautiful golf ball having excellent transfer property can be manufactured.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a golf ball or (2
A mold for molding an inner core sphere (of a peace ball).

[0002]

2. Description of the Related Art Conventionally, a mold for molding a golf ball or the above-mentioned inner core sphere (hereinafter sometimes simply referred to as a golf ball) is made of stainless steel, copper or the like as a base material and has a surface which comes into contact with a golf ball molding material. In addition, it is plated with chrome or nickel.

However, after the golf ball is molded, the releasability when the ball is taken out of the mold is poor.

In particular, the ionomer resin as the material of the two-piece ball or the material component of the inner core sphere (core) for the one-piece ball or the two-piece ball has an affinity with a metal such as an acrylic acid group or a methacrylic acid group. In addition, the mold release property is further deteriorated, and it may be impossible to take out the molded golf ball from the mold.

For this reason, a release agent has conventionally been applied.

[0006] Alternatively, (for a mold that does not use a mold release agent), there is one in which fluorine-based polymer fine particles are coated on a plating layer in a portion in contact with a golf ball molding material.

[0007]

When the mold release agent is applied to a mold and vulcanization molding is performed, a mold releasing agent is provided between the ball molding concave portion of the mold and the vulcanization molded ball. Since the molding agent remains, the molded ball may not be properly attached to the mold, or small pits (holes) may be formed on the surface of the ball taken out.

In the case of a one-piece ball, it is necessary to apply a paint to the surface of the ball after that, but this paint is difficult to adhere (because of the release agent), which causes peeling.

On the other hand, in the above-mentioned mold coated with fine particles of fluorine-based polymer, molding is continuously performed about 5 to 10 times,
There was a problem in terms of durability that the coating would peel off.

[0010]

DISCLOSURE OF THE INVENTION The present invention provides a mold for a golf ball having a chrome plating layer formed on the surface in contact with a golf ball molding material. The polymer particles were impregnated.

[0011]

Since a myriad of microcracks naturally occur on the surface of the chrome-plated layer, it can be used to the contrary to impregnate the fluorine-based polymer fine particles relatively easily.

The impregnated fluoropolymer fine particles exhibit non-adhesiveness with respect to the golf ball molding material, and greatly improve / improve the releasability when the golf ball is taken out after molding.

Further, since the cracks are deeply impregnated, the fluorine-based polymer fine particles are not lost even if they are repeatedly molded, and the durability is excellent.

[0014]

EXAMPLES Examples will be described below in detail.

FIG. 1 is a sectional view showing a part of a mold 2 for vulcanizing and molding the golf ball 1. Only the lower mold is shown in FIG. 1, but the upper mold is not shown above the drawing. Are arranged vertically symmetrically.

Reference numeral 3 is a concave portion into which a molding material M (shown by an imaginary line) for a golf ball (or an inner core sphere of a two-piece ball) is loaded. The concave portion 3 has a substantially hemispherical shape.

Small projections 5 for forming the dimples 4 are provided on the inner surface of the concave recess 3.

Thus, the chromium plating layer 6 is formed on the entire inner surface of the concave portion 3 and the peripheral surface thereof which the golf ball molding material M contacts.

FIG. 2 is an enlarged view of the main part of this FIG.
In FIG. 1, innumerable cracks 7 ... (Naturally) are formed in the chrome-plated layer 6 in a mesh pattern.

The cracked portions 7 are impregnated with fine particles 8 of a fluoropolymer such as polytetrafluoroethylene (hereinafter referred to as PTFE) to form a composite film W.

More specifically, the thickness T of the chromium plating layer 6 is set to 5 μm to 50 μm.

In particular, 25 μm to 35 μm is desirable. Also,
The film hardness of the chrome plating layer 6 is 700 (Hv) or higher. Especially, from the viewpoint of durability, 850 (Hv) to 1100 (H
v) is desirable.

The diameter of the fine particles 8 of a fluoropolymer such as PTFE is 10 μm or less, but in particular, 0.3 μm to 1.0 μm is preferable because it easily enters the crack portion 7.

Before the above-mentioned impregnation step, it is desirable that the originally existing crack portion is enlarged and its subdivided in cross section by a method such as chemical, electrochemical or mechanical. .. As a result, the ratio of the fine particles 8 of the fluorine-based polymer to the total surface area of the plating is sufficiently large (that is, when the concave portion 3 is explained, the crack surface 7 is exposed to the opening portion relative to the total surface area of the inner surface thereof). The ratio of the area of the fine particles of the fluorine-based polymer is preferably 20% to 25% --- the fluorine-containing polymer can be impregnated.

Further, the fluorine-based polymer fine particles 8 are charged, sufficient electrostatic electron energy is imparted thereto, and the heat-resistant modified resin binder is converted by a solvent, together with the cracked portion 7 after expansion and subdivision described above. Impregnate deeply. In addition, mechanical or physical press-fitting means may be added in some cases.

By the way, the thickness T of the chromium plating layer 6
Is preferably 25 μm to 35 μm for the following reason.

That is, for the durability, the film strength is sufficient to withstand the high-pressure molding of the golf ball 1, and the ratio of the area of the crack portion 7 containing the fine particles 8 of the fluoropolymer to the total plating surface area is 20. The above range of 25 μm to 35 μm is suitable for adjusting the amount to 25% to 25%. The "total plating surface area" means the total of the surface area of the chromium material of the chromium plating layer 6 and the surface area of the fine particles 8 in the cracked portion 7 exposed on the mold surface in FIG. And Also,
The “area of the crack portion 7” means the total area of the openings of the crack portion 7—therefore, the surface area of the fine particles 8 in the crack portion 7 exposed on the mold surface.

The golf ball 1 manufactured by the mold according to the present invention may be made of any material, for example, a rubber composition containing a base rubber and a co-crosslinking agent is vulcanized and molded. An unpainted golf ball produced by the above method, or a two-piece ball having a cover with an ionomer resin may be used. It also includes the inner core sphere of a two-piece ball.

Next, the following three types of golf ball molds A, B, and C were manufactured, and the following experiments were conducted for each of them.
Was carried out.

(Description of mold used) Mold A: product of the present invention; 0.3 μm to 1.0 μm after forming a chromium plating layer 6 having a film hardness of 900 (Hv) and a thickness dimension T of 30 μm. A mold for a golf ball in which PTFE having the particle diameter of 4 is impregnated into the cracked portion 7 to make the ratio of PTFE to the total plating surface area 22%. Mold B: Comparative example of conventional product (1); film hardness is 700
A golf ball mold having a (Hv) chrome plating layer 6 having a uniform thickness of 10 μm. Mold C: Comparative example of conventional product (2); film hardness is 700
A mold for a golf ball in which a chromium plating layer 6 of (Hv) is formed to have a uniform thickness of 10 μm, the surface is roughened by blasting, and PTFE is coated thereon to a uniform thickness of 30 μm.

(Experimental Method) Experiment: A molding material having the following composition (weight ratio) is charged into each mold and vulcanized and molded at 160 ° C. for 30 minutes to make a one-piece ball. High cis polybutadiene: 100 Zinc oxide: 23 Methacrylic acid: 24 Dicumyl peroxide: 1.5 Experiment: A molding material having the following composition (weight ratio) was charged as a cover molding material (half shell) into each mold, and the temperature was changed to 150 ° C. Three
Mold for a minute to make a two-piece ball. High Milan 1707: 50 High Milan 1706: 50 Titanium oxide: 1

The results of the above experiment are shown in Table 1 below.

[0033]

[Table 1]

The results of the above experiment are shown in Table 2 below.

[0035]

[Table 2]

From the above Tables 1 and 2, the mold A according to the present invention is remarkably superior to the conventional molds B and C in terms of mold releasability after molding the golf ball, and the durability is excellent. Is also clearly superior.

[0037]

EFFECT OF THE INVENTION The present invention has the above-mentioned structure and is excellent in mold releasability when the golf ball is taken out after molding and also in durability.

In addition, since it is not necessary to use a mold release agent, it is possible to prevent a defect in which small pits (holes) are formed on the surface of the molded golf ball, and it is possible to surely manufacture a golf ball having an excellent appearance and excellent appearance. It will be possible.

Also, with a one-piece ball (since no release agent is used), the paint can be easily applied to the surface after that, and the adhesion strength of the paint can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional explanatory view of a main part.

[Explanation of symbols]

 1 Golf Ball 6 Chromium Plating Layer 7 Cracks 8 Fine Particles M Molding Material

Claims (1)

[Claims] 1. A golf ball mold having a chrome-plated layer formed on the surface in contact with a golf-ball molding material, wherein the surface of the chrome-plated layer is impregnated with fluorine-based polymer particles. A mold for a golf ball, which is characterized in that