JP2000102630A - Manufacture and metal mold of golf ball and its core - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance releasability after a vulcanized molding, preserve the releasability for a long time and improve durability of a coating film by vulcanizingly molding using a metal mold whose inner cavity surface is coated with tungsten carbide/cobalt alloy at a specific film thickness by a melting and spraying method. SOLUTION: A spherical cavity is molded by mutually engaging upper and lower parts of metal molds 2, 2 which have hemispherical hollow concave parts (cavities) 3, and in this cavity, a core material 5 which is called, for example, a core for 2 piece balls, obtained by a press vulcanized molding or an injection vulcanized molding using a composition which is obtained by blending zinc methacrylate or zinc acrylate therein is provided. On the occasion, a coating layer with 22 μm to 200 μm film thickness is formed by melting and spraying tungsten carbide/cobalt alloy to the inner cavity surface 4 of each metal mold 2. Or a coating layer which is composed of tin or zinc or tin/zinc with 5 μm to 35 μm film thickness is formed in the cavity 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a golf ball or a core material thereof and a mold for molding the same.

[0002]

2. Description of the Related Art In general, in a one-piece ball or a core material of a multi-layered golf ball, zinc methacrylate or zinc acrylate is used in order to obtain good repulsion performance and (hitting ball) feeling. It is blended.

[0003] When the golf ball or its core material is vulcanized and molded in a mold and then taken out, the composition containing the above-mentioned zinc methacrylate or zinc acrylate has extremely poor releasability.

[0004] The main cause of the deterioration of the releasability of the above composition is zinc ion. This becomes clear when zinc is replaced with another metal in the mixture of butadiene rubber (BR) / zinc acrylate / zinc white / dicumyl peroxide, and suddenly turns to good mold release properties.

[0005] However, if it is replaced with another metal (other than zinc), the required physical properties as a golf ball (or its core material) cannot be achieved. Therefore, some release processing is required.

The release agent is generally dispersed or dissolved in a fluorine resin, a silicone resin, water or an organic solvent, and some of them have a transferability to a product and others do not. In the former case, steps such as buffing and washing are not taken in order to remove the release agent transferred before proceeding to the next step, so that the process cannot be complicated. On the other hand, in the latter case, there is no disadvantage of the former, but there is a problem in sustaining the releasability. This is because the strength of the coating itself is small, and in order to overcome this point, mold surface release treatment such as combined use with chromium plating or combined with nickel plating has been used. However, in the presence of the zinc ion as a causative substance, the coating strength is sufficient but the releasability is quite insufficient, and no treatment having both coating durability and releasability has been found.

In the invention of Japanese Patent Application Laid-Open No. Hei 7-148742 (Japanese Patent Application No. 5-296427) which has already been proposed by the present applicant, tungsten carbide is coated with a thickness of 2 μm to 20 μm. The durability of the golf ball or the core material thereof containing the zinc methacrylate or zinc acrylate containing zinc ions described above was insufficient.

[0008]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a golf ball or a core material containing zinc ions in a compounding material, which is excellent in releasability after vulcanization molding, and It is intended to provide a mold excellent in durability of the function of the release property and also excellent in coating durability, and
A golf ball or a core material containing the zinc methacrylate or the like, which has been said to have a very bad mold release property,
It is another object of the present invention to provide a method which can be easily released after vulcanization molding and can be efficiently and stably manufactured as a high-quality product for a long period of time.

[0009]

Therefore, a method of manufacturing a golf ball or a core material thereof according to the present invention is as follows: a tungsten carbide / cobalt alloy is sprayed by a spray method to a thickness of 22 μm to 200 μm.
m with a film thickness of m
This is a vulcanization molding method.

[0010] Also, there is a method in which tungsten or cobalt is vulcanized and molded by a spraying method in a mold in which the inner surface of the cavity is formed to a thickness of 22 µm to 200 µm.

[0011] The inner surface of the cavity is 5 μm to 35 μm.
This is a method in which vulcanization molding is carried out using a mold treated with tin, lead, or a tin / lead alloy to a film thickness of.

Further, the inner surface of the cavity is set to a thickness of 0.3 μm to 3.5 μm.
This is a method of performing vulcanization molding using a mold treated with boron nitride, chromium nitride, or titanium nitride to a layer thickness of μm.

In addition, vulcanization molding is performed using a metal mold containing boron nitride as a base material. Alternatively, vulcanization molding is performed using a mold in which fluorine ions have been implanted into the inner surface of the cavity.

The molding die of the present invention is formed by coating a tungsten carbide / cobalt alloy with a thickness of 22 μm to 200 μm on the inner surface of the cavity.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail. In FIG. 1, reference numerals 2 and 2 denote upper and lower molds each having a hemispherical concave portion (cavity) 3. When the concave concave portions (cavities) 3 and 3 of both molds 2 and 2 are combined, a spherical cavity is formed. To form

Reference numeral 5 denotes a core material called, for example, a two-piece ball core. The dies 2 and 2 are press-type vulcanization molding apparatuses or injection-type vulcanization molding apparatuses. Is installed.

In the case of the core member 5, the inner surface of the cavity 4 キ ャ ビ テ ィ
There is no small protrusion on the {inner surface of the concave portion 3},
When the sphere to be vulcanized is a golf ball (not shown), a number of small protrusions are formed on the inner surface 4 of the cavity.
To form dimples of the golf ball.

FIG. 2 is an enlarged sectional view of a main part of FIG. 1. A coating layer 6 is formed on the inner surface 4 of the cavity by spraying a tungsten carbide / cobalt alloy.

The thickness (layer thickness) T of the coating layer 6 is 22 μm.
It is set in the range of 200 μm (see Example 1, Example 2, Example 3, Example 28, and Example 29 in Table 1 described later).
Therefore, the surface (cavity inner surface 4) in contact with the material to be vulcanized (raw rubber) is a tungsten carbide / cobalt alloy.

When the film thickness (layer thickness) T is less than 22 μm, the durability in the thick direction is insufficient (see Comparative Example 1 in Table 2 described later). Conversely, when the film thickness (layer thickness) T exceeds 200 μm, the durability in the shearing direction is insufficient (see Comparative Example 2 in Table 2 described below: peeling is performed 100 times).

Golf ball or core material 5 according to the present invention
Is a method of vulcanizing and molding a tungsten carbide / cobalt alloy on a cavity inner surface 4 with a film thickness T of 22 μm to 200 μm by a spraying method in a mold 2 coated and formed as described above. Is the way.

As another embodiment, a golf ball or a metal is formed by spraying tungsten or cobalt in a mold 2 having a coating layer 6 formed on the inner surface 4 of the cavity with a film thickness T of 22 μm to 200 μm. This is a manufacturing method of vulcanizing and molding the core material 5 (see Example 4 or Example 5, and Example 30, Example 31, Example 32 or Example 33 in Table 1 described later).

When the film thickness (layer thickness) T is less than 22 μm, the durability in the thick direction is insufficient (see Comparative Examples 20 and 22 in Table 2). Conversely, when the film thickness (layer thickness) T exceeds 200 μm, the durability in the shearing direction becomes insufficient (Comparative Example 21, Table 2 in Table 2).
See Comparative Example 23).

Next, as another embodiment, a surface in contact with the material to be vulcanized (rubber) {the inner surface 4 of the cavity}.
Is a vulcanization molding method using a mold 2 that is plated with tin (tin) or lead or an alloy thereof (tin / lead alloy).

The plating film thickness T (see FIG. 2) is 5 μm to
35 μm is preferred (see Examples 6 to 10 in Table 1).
When the thickness is less than 5 μm, the durability of the coating layer (plated layer) 6 in the thick direction may be insufficient (Comparative Examples 24 and 24 in Table 2).
On the other hand, if it exceeds 35 μm, the durability in the shearing direction may be insufficient (see Comparative Examples 25, 27 and 29 in Table 2).

In still another embodiment, a surface in contact with the material to be vulcanized (rubber) {the inner surface 4 of the cavity}.
Is a vulcanization molding of a golf ball or its core material 5 in a mold 2 treated with boron nitride, chromium nitride or titanium nitride.

In order to perform surface treatment of the cavity inner surface 4 with boron nitride, a vapor phase coating method is preferable, and a CVD method (thermal CVD or plasma CVD method), a PVD method, an ion plating method, a sputtering method, and a high frequency sputtering method are used. Various gas phase coating methods such as an ion beam method and the like can be used.

In this case, the thickness of the coating layer (layer thickness)
T is desirably 0.3 μm to 3.5 μm (Example 11 in Table 1).
To Example 14). When the thickness is less than 0.3 μm, the durability in the thick direction may be insufficient (see Comparative Example 30 in Table 2). Conversely, when the thickness exceeds 3.5 μm, the durability in the shear direction may be insufficient (see Table 2). See Comparative Example 31).

When the surface is treated with chromium nitride or titanium nitride, various vapor phase coating methods similar to the above-mentioned boron nitride can be used, and the thickness T of the coating layer is the same for the same reason. (See Examples 20 to 27 and Comparative Examples 32 to 35 in Table 1).

Another embodiment is a manufacturing method in which vulcanization molding is performed using a metal mold containing boron nitride as a base material. That is, as shown in FIG. 3, a block containing 50% or more of boron nitride.
The mold 12 is manufactured by machining such as cutting and grinding.

Such a mold 12 is referred to as a "mold using boron nitride as a base material". In Example 15 in Table 1,
Boron nitride in a mold based on boron nitride is 99%, boron nitride is 95% in Example 16, boron nitride is 90% in Example 17, and boron nitride is 18% in Example 18. About 60%. Therefore, referring to FIG. 1, the entire mold 2 is manufactured by machining from the “boron nitride block 7”, and the entire mold 2 is made of the same material. As the boron nitride block 7, "boron nitride" commercially available from Denki Kagaku Kogyo KK can be used.

As still another embodiment, a golf ball or its core material 5 is formed by a mold in which fluorine ions are implanted into a surface (cavity inner surface 4) in contact with rubber.
Is a production method of vulcanization molding. For the implantation of fluorine ions, an ion plating method, an ion beam method, or the like is used (see Example 19 in Table 1). The fluorine ions began to be slightly impregnated from the inside of the cavity inner surface 4 from the inside, and the measurement of the layer thickness was omitted because it was difficult.

[0033]

EXAMPLES In order to produce a golf ball core material 5, the composition was kneaded by a known method so that the following weight ratio was obtained. BR01 (cis 97% polybutadiene manufactured by Japan Synthetic Rubber) 100 parts by weight Zinc acrylate 25 parts by weight Zinc white powder 20 parts by weight Dicumyl peroxide (peroxide) 1 part by weight

This composition is pressed into a sphere between the upper and lower molds 2 and 2 as shown in FIG. 1 and vulcanized at 170 ° C. for 5 minutes. The number of times until the mold release from 2 becomes difficult, or the cavity inner surface 4 peels off,
The number of times before damage such as cracking (referred to as “the number of times of release”) was examined. The measurement results are shown in Table 1 below.

[0035]

[Table 1]

In Table 1, if the number of times of release is 150 or more, it is judged that there is good release property and durability.

Next, the mold in the case where the film thickness T is too small or too large (Comparative Example 1, Comparative Example 2, and Comparative Examples 20 to 35) and the coating layer 6 of the mold 2 of the present invention will be described. A mold (Comparative Example 3, Comparative Example 4, Comparative Example 5, Comparative Example 6, Comparative Example 7) in which a completely different material was plated (or coated) was different from the mold 12 of FIG. 3 of the present invention. Using molds (Comparative Examples 8 to 19) cut and formed from blocks of different materials, the same composition as described above was press-molded and vulcanized under the same vulcanization conditions. , And the number of times of release from each was examined.
The measurement results are shown in Table 2 below.

[0038]

[Table 2]

As apparent from Table 2, Comparative Examples 1 and 2
In Comparative Example 2 and Comparative Examples 20 to 35, the number of times of release was 60 to 140 times, and all were less than 150 times. In this case, there is a problem in durability or the like, and it can be said that it cannot be practically used.

In the case of the Teflon coating shown in Comparative Example 4, the number of times of release was 100 times, which did not reach 150 times, indicating that it was not practically usable. In addition, Comparative Examples 3, 3, and 6 cannot be used, and Comparative Examples 7 to 19 can hardly remove the vulcanized molded product (core material) from the cavity from the first time, or have the inner surface of the cavity. Are damaged almost the first time.

[0041]

According to the present invention, good release properties can be obtained after vulcanization molding even with a golf ball made of a material containing zinc methacrylate or zinc acrylate, or a core material thereof. It is excellent in the long-term persistence of the releasing property, excellent in the durability of the mold, and can efficiently and stably produce high-quality products for a long period of time.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part for explaining a mold and a manufacturing method.

FIG. 2 is an enlarged sectional view of a main part of FIG. 2;

FIG. 3 is an explanatory view showing an example of a method for manufacturing a mold.

[Explanation of symbols]

 2 Mold 4 Cavity inner surface 5 Core material 6 Coating layer 12 Mold T Film thickness (layer thickness)

Claims (7)

[Claims] 1. A vulcanization molding of a tungsten carbide / cobalt alloy in a mold 2 coated on a cavity inner surface 4 with a film thickness T of 22 μm to 200 μm by a spraying method. A method for producing a golf ball or its core material. 2. A cavity inner surface 4 having a thickness T of 22 μm to 200 μm formed by spraying tungsten or cobalt.
And vulcanizing and molding with a mold 2 coated on a golf ball. 3. A golf ball or its core, wherein the cavity inner surface 4 is vulcanized and molded in a mold 2 treated with tin or lead or a tin / lead alloy to a thickness T of 5 μm to 35 μm. The method of material production. 4. The method according to claim 1, wherein the inner surface of the cavity is 0.3 μm to 3.5 μm.
A golf ball or a core material thereof, which is vulcanized in a mold 2 having a thickness T of m and treated with boron nitride, chromium nitride or titanium nitride. 5. A method for producing a golf ball or a core material thereof, which is carried out by vulcanization molding using a mold 12 containing boron nitride as a base material. 6. A method for producing a golf ball or a core material thereof, wherein the molding is performed by vulcanization molding using a mold in which fluorine ions have been implanted into the cavity inner surface 4. 7. A mold for molding a golf ball or a core material thereof, wherein a tungsten carbide / cobalt alloy is coated on the inner surface 4 of the cavity with a thickness T of 22 μm to 200 μm.