JP2003305743A - Mold for golf ball, manufacturing method therefor, and golf ball manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold 1 for a golf ball exerting no adverse effect on the physical properties of the golf ball and having good lasting releasability. <P>SOLUTION: The mold 1 comprises a base part 6, a substrate layer 7 and a release layer 8. The release layer 8 comprises first and second release layers 9 and 10. The substrate layer 7 comprises a composite film containing nickel and a fluorine type polymeric compound dispersed in nickel. The first release layer is obtained by substituting nickel of a preparatory composite film containing nickel and the fluorine type polymeric compound dispersed in nickel with gold. The second release layer 10 is a composite film containing gold and the fluorine type polymeric compound dispersed in gold. The content of the fluorine type polymeric compound in the second release layer is 15-40 vol.%. The sum total thickness of the first and second release layers 9 and 10 is 0.5-3 μm. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a golf ball mold and a golf ball manufacturing method using the mold.

[0002]

Golf balls are composed of a main body and a paint layer formed on the surface of the main body. The main body is almost spherical except that dimples are formed on the surface.
Golf balls are classified into one-piece golf balls, two-piece golf balls, multi-piece golf balls (where the main body is composed of three or more layers), and wound golf balls according to the structure of the main body.

In a two-piece golf ball, a main body is composed of a core and a cover that covers the surface of the core.
This core is a sphere, and the rubber composition is put into a mold including an upper mold and a lower mold each having a hemispherical cavity,
This rubber composition is molded by being heated and pressed. Upon heating, the rubber composition causes a crosslinking reaction.
The molded core is taken out of the mold.

Usually, the core is blended with zinc methacrylate or zinc acrylate as a co-crosslinking agent. Due to the influence of the co-crosslinking agent, the core surface and the surface of the mold (cavity surface) may come into close contact with each other in the crosslinking step, and it may be difficult to remove the core from the mold. This phenomenon is called "demolding failure". When the mold release is defective, the productivity of golf balls is reduced.

After the core is taken out, a deposit may be deposited on the cavity surface. The adhered matter promotes mold release failure. Molds with a high degree of accumulation cannot be used and are removed from the molding machine and cleaned. Mold removal and cleaning significantly reduces golf ball productivity.

In molding the main body of a two-piece golf ball, the cover and the cavity surface of the mold contact each other. An ionomer resin is usually used for the cover. In this ionomer resin, metal ions are used to neutralize the carboxylic acid component. This metal ion exists in the ionomer resin in a highly ionic state. At the time of molding the main body, the metal ions and the cavity surface may chemically react with each other, which may cause mold release defects. Even in the molding of the main body, the mold release defect is promoted by the deposits deposited on the cavity surface.

The problem of decreased productivity due to defective release also occurs in the case of molding the body of a one-piece golf ball; the core, intermediate layer and body of a multi-piece golf ball; and the center and body of a wound golf ball. Also, mold release defects occur during molding of the half shells for the intermediate layer and the cover.

Attempts have been made to improve releasability by changing the co-crosslinking agent blended in the rubber composition (see JP-A-11-89968). Although the mold releasability is improved by the use of a co-crosslinking agent other than zinc methacrylate and zinc acrylate, the resilience characteristics, shot feeling and durability that are originally required for golf balls have to be sacrificed to some extent. There's a problem.

A technique has also been proposed in which an internal release agent is added to a molding material (rubber composition or resin composition) (JP-A-57-78875 and JP-A-11-169485).
(See Japanese Patent Publication). However, this technique is not practical since the ball physical properties such as durability and resilience are sacrificed and the releasability is emphasized.

For the purpose of improving the releasability, a silicone type releasing agent or a fluorine type releasing agent may be applied to the cavity surface. In addition, a technique of improving the releasability by a release film interposed between the molding material and the cavity surface has also been proposed (see JP-A-11-169487). However, since the release agent or the release film migrates to the surface of the molded body, this may cause poor adhesion between the molded body and the layer in contact with the molded body. For example, when the core is molded, poor adhesion between the core and the cover that is the upper layer of the core may occur, and when the main body is molded, poor adhesion between the main body and the paint layer may occur. If the release agent or the release film is removed from the molded product by surface polishing or cleaning, the poor adhesion is eliminated, but this removal process rather reduces the productivity of the golf ball. Moreover, since the mold release agent gradually disappears by repeated molding, the mold releasability does not last long.

For the purpose of improving releasability, a silicone-based releasing agent or a fluorine-based releasing agent may be applied to the surface of a plug (preformed body) which is a molding material (JP-A-6-344).
353). However, since the release agent remains on the surface of the molded body, this causes poor adhesion between the molded body and the layer in contact with the molded body.

There has also been proposed a mold for a golf ball provided with a release layer composed of a composite film in which fluororesin particles are dispersed in a nickel matrix (see Japanese Patent Laid-Open No. 9-300361). However, the mold release effect does not last long with this mold. In particular, when a molded product is obtained from a rubber composition containing zinc methacrylate or zinc acrylate, the releasability is severely reduced.

[0013]

As described above, all the conventionally proposed means for improving releasability have some drawbacks. The fact is that a means for improving releasability that is satisfactory in terms of both durability and physical properties of balls has not yet been obtained.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a mold for a golf ball which does not adversely affect the physical properties of the ball and which has a good releasing property for a long time. is there. Yet another object of the present invention is to provide a golf ball manufacturing method with excellent productivity.

[0015]

SUMMARY OF THE INVENTION The invention made to achieve the above object is a mold for a golf ball comprising a base and a release layer coating the surface of the base. A mold for a golf ball, wherein the mold layer is a composite film containing gold and a fluorine-based polymer compound dispersed in the gold.

Since the release layer of this mold is rich in water repellency, the deposition of deposits is suppressed. Moreover, since this release layer has a low friction property, the deposits once deposited are likely to be released. Therefore,
With this mold, mold release defects are suppressed. Since the release layer hardly transfers to the molded body, it does not adversely affect the physical properties of the golf ball. Since the release layer has excellent durability, the good release property continues for a long time.

Preferably, the fluorine-containing polymer compound has a network structure on the surface of the release layer. This mesh structure contributes to the water repellency and low friction of the mold.

Preferably, the content of the fluorine-containing polymer compound in the release layer is 15% by volume or more and 0% by volume or less. This release layer is particularly excellent in releasability. When the release layer is composed of a plurality of layers, the content of the fluorine-containing polymer compound in the outermost layer is within the above range.

The thickness of the release layer is preferably 3 μm or more and 15 μm or less. This release layer is particularly excellent in durability. When the release layer is composed of a plurality of layers, the total thickness of all layers is within the above range.

From the viewpoint of releasability, the preferred fluorine-containing polymer compound is a polymer compound having a perfluoroalkyl group or a polyfluoroalkyl group. Specifically, polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride and a tetrafluoroethylene-hexafluoropropylene copolymer are preferable.
These fluoropolymer compounds may be used alone or in combination of two or more.

The contact angle of water on the surface of the release layer is preferably 100 ° or more and 140 ° or less. This mold is particularly excellent in releasability.

Preferably, the mold comprises an underlayer between the base and the release layer. The underlayer is composed of a composite film containing nickel and a fluorine-based polymer compound dispersed in the nickel. This underlayer contributes to improving the adhesion between the base and the release layer.

Preferably, the release layer comprises a first release layer formed on the surface of the underlayer and a second release layer formed on the surface of the first release layer. The first release layer is obtained by substituting gold for nickel in the preliminary composite film containing nickel and the fluorine-containing polymer compound dispersed in the nickel. This first release layer contributes to the improvement of the adhesion between the underlayer and the second release layer.

Another invention made to achieve the above object is a method for manufacturing a golf ball mold, which includes the following steps (1) and (2). (1) A step of forming a release layer made of a composite film containing gold and a fluorine-based polymer compound dispersed in the gold on the front side of the base. (2) A step of heat-treating the base and the release layer to a temperature equal to or higher than the melting point of the fluorine-based polymer compound.

In this manufacturing method, the fluorine-containing polymer compound is melted by the heat treatment and bonded in the form of a mesh on the surface of the release layer. This improves the water repellency and low friction of the release layer.

Still another invention made to achieve the above object is a method for manufacturing a golf ball mold, which includes the following steps (1) to (3). (1) A step of forming a preliminary composite film containing nickel and a fluorine-based polymer compound dispersed in the nickel on the front side of the base. (2) A step of substituting gold for gold near the surface of the preliminary composite coating to form a first release layer. (3) A step of forming a second release layer composed of a composite film containing gold and a fluorine-based polymer compound dispersed in the gold on the surface of the first release layer.

In this manufacturing method, a part of the preliminary composite film becomes the first release layer and the remaining part becomes the underlayer. Since the first release layer and the base layer have the same origin, they are unlikely to separate from each other. Since the first release layer and the second release layer are homogeneous materials,
Peeling of both does not occur easily. The release layer obtained by this production method is particularly excellent in durability.

Still another invention made in order to achieve the above-mentioned object is to provide a mold having a release layer composed of a composite film containing gold and a fluorine-containing polymer compound dispersed in the gold on the surface thereof. A method for manufacturing a golf ball, which comprises a step of molding a main body of a golf ball or a part thereof.

According to this manufacturing method, it is difficult for the productivity to decrease due to defective release. This production method exerts a particularly remarkable effect when the surface of the molded article is made of a rubber composition containing zinc methacrylate or zinc acrylate, or when it is made of an ionomer resin composition.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, with reference to the drawings,
The present invention will be explained in detail based on the preferred embodiments.

FIG. 1 is a front view showing a mold 1 according to an embodiment of the present invention. A core of a two-piece golf ball is molded by this mold 1. The mold 1 includes an upper mold 2 and a lower mold 3. Each of the upper mold 2 and the lower mold 3 includes hemispherical cavity surfaces 4 and 5. When the mold is clamped, both cavity surfaces 4 and 5 are brought together to form a spherical cavity. The rubber composition is put into this cavity.

FIG. 2 is an enlarged sectional view showing a part of the lower mold 3 of the mold 1 of FIG. The lower mold 3 includes a base 6, a base layer 7, and a release layer 8. The release layer 8 is the first release layer 9
And the second release layer 10. The surface of the release layer 8 is the cavity surface 5. The base 6 is made of a metal material. Stainless steel, brass or the like is usually used for the base 6. Although not shown, the upper mold 2 and the lower mold 3 are also
It has the same sectional shape as.

FIG. 3 is a flow chart showing an example of a method of manufacturing the mold 1 of FIG. In this manufacturing method, first, the base 6 is prepared (STP1). The base 6 is made of stainless steel (for example, SUS3 specified in JIS).
03).

Next, the base 6 is subjected to pretreatment (STP).
2). The pretreatment is preferably performed according to the following procedure. By this pretreatment, the deposits are removed from the surface of the base 6. (1) Alkaline immersion degreasing using immersion degreaser (5 minutes at room temperature) (2) Washing with water (3) Cathodic electrolytic degreasing using electrolytic degreasing agent containing sodium hydroxide (5 minutes at room temperature) (4) Washing with water (5) Pickling with 10 mass% hydrochloric acid aqueous solution (1 minute at room temperature) (6) Washing with water (7) Nickel strike with nickel chloride and hydrochloric acid (1 minute at room temperature) (8) Washing with water

Next, as shown in FIG. 4A, a preliminary composite film 11 is formed on the surface of the base 6 (STP).
3). The preliminary composite film 11 contains nickel and a fluorine-based polymer compound. The fluorine-based polymer compound is in the form of fine particles and is dispersed in the nickel matrix. Preferably, a nickel-phosphorus plating bath in which fine particles of a fluoropolymer compound are dispersed by a surfactant is used to form the preliminary composite film 11 by electroless plating. This plating is called composite nickel plating. The bath temperature of the plating bath is preferably 88 ° C or higher and 92 ° C or lower, and particularly preferably 90 ° C or higher and 91 ° C or lower. The bath ratio is 0.
5 dm ² / L or more 1.5 dm ² / L or less,
It is particularly preferably 0.7 dm ² / L or more and 0.9 dm ² / L or less. The nickel concentration is preferably 4.6 g / L or more and 5.1 g / L or less, and particularly preferably 4.9 g / L or more and 5.0 g / L or less. The pH is preferably 4.8 or more and 5.2 or less,
It is particularly preferably 4.9 or more and 5.1 or less.

Preferably, a hypophosphite as a reducing agent and a complexing agent are added to the plating bath. As a result, phosphorus is uniformly deposited on the preliminary composite coating 11, and the corrosion resistance of the base layer 7 derived from the preliminary composite coating 11 is improved.

The content of the fluorine-containing polymer compound in the preliminary composite film 11 is preferably 15% by volume or more and 40% by volume or less. If the content is less than the above range, the migration of the fluorine-based polymer compound to the release layer 8 described below may not be sufficient. From this viewpoint, the content is particularly preferably 20% by volume or more. If the content exceeds the above range, the strength of the underlayer 7 obtained from the preliminary composite coating 11 may be insufficient. From this viewpoint, the content is particularly preferably 35% by volume or less.

The fluorinated polymer compound that can be used is a polymer having a group in which all or part of hydrogen atoms of a hydrocarbon group are substituted with fluorine atoms, specifically, a perfluoroalkyl group or a polyfluoroalkyl group. It is a compound. Suitable fluorine-based polymer compounds are polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride and tetrafluoroethylene-hexafluoropropylene copolymer, and particularly easily available polytetrafluoroethylene (PTFE). preferable. These fluoropolymer compounds may be used alone or in combination of two or more. The fluorine-based polymer compound diffuses into the mold release layer 8 and contributes to the mold releasability of the mold 1.

Next, displacement gold plating (STP4) is performed. In this displacement gold plating, nickel near the surface of the preliminary composite film 11 is replaced with gold. The replacement portion of the preliminary composite film 11 becomes the first release layer 9 as shown in FIG. The first release layer 9 is a composite film in which fine particles of a fluorine-based polymer compound are dispersed in gold. The content rate of the fluoropolymer in the first release layer 9 is almost the same as the content rate of the fluoropolymer compound in the preliminary composite film 11. The portion of the preliminary composite film 11 that has not been replaced becomes the base layer 7 shown in FIG. 4 (b). In other words, the first release layer 9 and the base layer 7 are obtained from the preliminary composite film 11. The underlayer 7 is a composite film containing nickel and a fluorine-based polymer compound dispersed in the nickel.

Preferably, a displacement gold plating bath containing organic acid gold is used for the displacement gold plating (STP4), and the base portion 6 is immersed in this plating bath. By immersion, nickel having a large ionization tendency is eluted from the preliminary composite film 11, and free electrons generated at this time reduce gold ions to deposit. The reduction reaction is stopped when the entire surface of the preliminary composite film 11 is covered with gold. Therefore, the thickness of the first release layer 9 does not become so large. The bath temperature in displacement gold plating (STP4) is preferably about 80 ° C, and the bath ratio is about 1.0 dm ² / L.
Is preferable, the gold concentration is preferably about 2.0 g / L, and the pH is
Is preferably 6-8.

The thickness of the underlayer 7 is preferably 1 μm or more and 10 μm or less. When the film thickness is less than the above range, the release layer 8
The adhesion between the base and the base 6 may be insufficient. From this viewpoint, the film thickness is particularly preferably 3 μm or more. When the film thickness exceeds the above range, it is uneconomical. From this viewpoint, the film thickness is 5
It is particularly preferable that the thickness is μm or less.

Next, the second release layer 1 shown in FIG. 4 (c).
0 is formed (STP5). This second release layer 10 is
A composite film containing gold and a fluorine-based polymer compound. The fluorine-based polymer compound is in the form of fine particles and is dispersed in the gold matrix. Preferably, the second release layer 10 is formed by electroless plating using a self-catalytic non-cyanide gold plating bath in which fine particles of a fluoropolymer compound are dispersed by a surfactant. This plating is called composite gold plating. By this plating, gold and the fluoropolymer compound are codeposited. The bath temperature of the plating bath is 70
℃ or more and 90 ℃ or less, the bath ratio is 1.0 dm ² / L
A preferable level is 1.0 g / L or more and a gold concentration of 3.0 g / L.
L or less is preferable, and pH is preferably 6.5 or more and 10 or less.

Examples of preferable surfactants for dispersing the fluorine-containing polymer compound include cationic surfactants and nonionic / cationic mixed surfactants.
These surfactants suppress aggregation of the fluoropolymer compound in the plating bath.

The fluorinated polymer compound that can be used is a polymer having a group in which all or part of hydrogen atoms of a hydrocarbon group are substituted with fluorine atoms, specifically, a perfluoroalkyl group or a polyfluoroalkyl group. It is a compound. Suitable fluorine-based polymer compounds are polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride and tetrafluoroethylene-hexafluoropropylene copolymer, and polytetrafluoroethylene, which is easily available, is particularly preferable. These fluoropolymer compounds may be used alone or in combination of two or more. Usually, the second release layer 10 is made of the same fluoropolymer compound as that used for the preliminary composite film 11.

The method for forming the second release layer 10 is not limited to electroless plating, but electrolytic gold plating may be used.

Next, the base 6 is subjected to heat treatment (ST
P6). The treatment temperature is set to be equal to or higher than the melting point of the fluoropolymer compound. Usually, the temperature is set to 220 ° C. or higher and 360 ° C. or lower. For example, when polytetrafluoroethylene is used, the temperature is preferably set to 330 ° C or higher and 360 ° C or lower. After the heat treatment, the base 6 is cooled and the mold 1 is obtained.

By the heat treatment (STP6), the mechanical strength of the underlayer 7 is remarkably improved, and the durability and wear resistance of the mold 1 are improved. Further, the fluorine-based polymer compound of the release layer 8 is melted and diffused by heating, and then the surface of the release layer 8 has a mesh structure by cooling. The network structure is a structure in which particles of a fluorine-based polymer compound are bonded to each other. This mesh structure enhances the water repellency and low friction of the mold 1. The mold 1 is extremely excellent in releasability.

The content of the fluoropolymer compound in the second release layer 10 is preferably 15% by volume or more and 40% by volume or less. If the content is less than the above range, the releasability may be insufficient. From this viewpoint, the content rate is 20% by volume.
The above is particularly preferable. When the content exceeds the above range, the strength of the second release layer 10 may be insufficient. From this viewpoint, the content is particularly preferably 35% by volume or less.

The thickness of the release layer 8 (total of the first release layer 9 and the second release layer 10) is preferably 0.5 μm or more and 3 μm or more. If the film thickness is less than the above range, the releasability of the mold 1 and the durability of the release layer 8 may be insufficient. When the film thickness exceeds the above range, it is uneconomical. From this viewpoint, the film thickness is particularly preferably 2 μm or less.

Since both the base layer 7 and the first release layer 9 are derived from the preliminary composite film 11, both are firmly adhered. On the other hand, since the first release layer 9 and the second release layer 10 are similar in composition to each other, they are firmly adhered to each other. Further, nickel is originally excellent in adhesion to gold. In the mold 1, peeling of the release layer 8 is unlikely to occur.

The contact angle of water on the surface of the release layer 8 (indicated by symbol α in FIG. 5) is 100 ° (de
It is preferably at least gree) and 140 ° or less. When the contact angle α is less than the above range, the releasability may be insufficient. From this viewpoint, the contact angle α is particularly preferably 105 ° or more. If the contact angle α exceeds the above range, the durability may be insufficient. From this viewpoint, the contact angle α is 1
35 ° or less is particularly preferable. The contact angle α is measured by dropping a water droplet 13 on the surface 12 of the release layer 8.

In the pretreatment step (STP2), the surface of the base 6 is nickel-strike. However, surface treatment such as sputtering or etching may be applied instead of the nickel strike.

The method of forming the underlayer 7 is not limited to the composite nickel plating, but may be nickel alloy plating or cobalt alloy plating. The underlayer obtained by these platings also has excellent adhesion to the release layer 8.
When the adhesion between the base 6 and the second release layer 10 is sufficient, the base layer 7 and the first release layer 9 may not be formed.

FIG. 6 shows a core 1 formed by the mold 1 shown in FIG.
4 is a partially cutaway sectional view showing a golf ball 15 in which No. 4 is used. FIG. The golf ball 15 includes a cover 16 that covers the surface of the core 14. The core 14 and the cover 16 form a main body 17 of the golf ball 15. Although not shown, a paint layer is formed on the surface of the main body 17.

The core 14 is formed by crosslinking a rubber composition. The type of base rubber used in the rubber composition is not particularly limited, but high-cis polybutadiene, which is excellent in resilience, is usually used. Further, for the crosslinking of the base rubber, zinc methacrylate or zinc acrylate as a co-crosslinking agent is used together with the peroxide. The core 14 using this co-crosslinking agent contains zinc ions,
The chemical reaction between the zinc ions and the mold 1 is suppressed by the release layer 8.

The cover 16 is made of an ionomer resin as a base material. Also in the step of covering the core 14 with the cover 16 (that is, the step of molding the main body 17), a mold including an upper mold and a lower mold each having a hemispherical cavity is used, and a molding method such as a compression molding method or an injection molding method. Done by This mold also has a release layer obtained by composite gold plating on its surface. In the molding of the main body 17, a thermoplastic composition containing an ionomer resin is a material forming the surface. This ionomer resin is composed of α-olefin and α, β
A thermoplastic resin in which a carboxylic acid component in a copolymer with an unsaturated carboxylic acid is neutralized with a metal ion.
The ionomer resin contains the metal ions used for neutralization, but the chemical bond between the metal ions and the mold is suppressed by the release layer. The ionomer resin suitable for the cover 16 from the viewpoint of resilience, shot feeling, durability, etc., uses ethylene or propylene as the α-olefin,
Acrylic acid or methacrylic acid is used as the β-unsaturated carboxylic acid. In molding the main body 17 including the ionomer resin in the cover 16, the release layer obtained by composite gold plating is particularly effective.

As described above, the effect of the release layer obtained by the composite gold plating is described in detail by taking the two-piece golf ball in which the main body 17 is composed of the core 14 and the cover 16, as an example. This release layer is also effective in the step of forming the member. For example, in the case of a core composed of three crosslinked rubber layers of a first layer, a second layer and a third layer from the inside to the outside, (1) a molding step of a first layer which is a sphere, (2) a first layer In the molding step of the sphere consisting of the second layer and (3) the molding step of the sphere consisting of the first layer, the second layer and the third layer (that is, the core), the release property is improved by the composite gold plating.

Further, for example, in the case of a main body composed of a core made of crosslinked rubber, a first cover containing an ionomer resin and a second cover containing an ionomer resin, (1) a step of molding a spherical core, (2) a core and a second core In the step of forming a sphere consisting of one cover and (3) the step of forming a sphere (that is, main body) consisting of the core, the first cover and the second cover
The release property is improved by the composite gold plating.

Further, in the molding process of the one-piece golf ball whose main body is composed of a single crosslinked rubber layer and the molding process of the solid center and the cover of the thread wound golf ball, the release property is improved by the composite gold plating.
Further, in the molding process of the half shell for the cover and the intermediate layer, the release property is improved by the composite gold plating.

[0060]

The effects of the present invention will be clarified by the following examples, but the present invention should not be construed in a limited way based on the description of the examples.

[Example 1] The base of the mold shown in Fig. 1 was prepared, and alkaline immersion degreasing was carried out at room temperature for 5 minutes, cathodic electrolytic degreasing was carried out at room temperature for 5 minutes, pickling was carried out at room temperature for 15 minutes, and at room temperature. A one minute nickel strike was applied. Next, on the surface of the base portion, a pre-composite coating in which particles of polytetrafluoroethylene were dispersed in a nickel matrix was formed by electroless composite nickel plating. The content of polytetrafluoroethylene in this preliminary composite film was 30% by volume. Next, nickel in the vicinity of the surface of the preliminary composite coating was replaced with gold by displacement gold plating. As a result, an underlayer having a thickness of 5 μm and a first release layer having a thickness of 0.5 μm were formed from the preliminary composite coating. Next, a second release layer having polytetrafluoroethylene particles dispersed in a gold matrix was formed by electroless composite gold plating. The content of polytetrafluoroethylene in this second release layer was 30% by volume. The total thickness of the first release layer and the second release layer is 6 μm. Next, this base was kept in an environment of 350 ° C. for 30 minutes and cooled to obtain a mold of Example 1. When the surface of the release layer of this mold was observed by SEM, the diameter was about 0.2.
There were many polytetrafluoroethylene fine particles having a size of μm. These fine particles had a network structure in which they were connected to each other.

[Examples 2 and 3] Example 2 was repeated in the same manner as in Example 1 except that the treatment conditions for electroless composite gold plating were changed and the thickness of the release layer was as shown in Table 1 below. And molds 3 were obtained.

[Examples 4 and 5] Example 4 and 5 were carried out in the same manner as in Example 1 except that the treatment conditions for electroless composite gold plating were changed so that the content of polytetrafluoroethylene was as shown in Table 1 below. The molds of Examples 4 and 5 were obtained.

[Comparative Examples 1 and 2] As Comparative Example 1, a mold including only the base was prepared. In addition, as Comparative Example 2,
A mold having only a base and having a cavity surface coated with a release agent was prepared.

Comparative Example 3 The same pretreatment as in Example 1 was applied to the base, and a release layer having polytetrafluoroethylene particles dispersed in a nickel matrix was formed by complex nickel plating. Got the mold.

Comparative Example 4 A mold of Comparative Example 4 was obtained by forming a fluorine-based film on the surface of the base by coating.

[Evaluation of releasability] High-cis polybutadiene (trade name "BR01" manufactured by JSR) 100
Parts, 30 parts of zinc acrylate, 20 parts of zinc oxide and 0.5 parts of dicumyl peroxide were kneaded with a closed kneader and an open roll to obtain a rubber composition. This rubber composition was put into a mold, the mold was clamped, and heated at 160 ° C. for 30 minutes. The heating caused the rubber composition to undergo a crosslinking reaction to form a spherical core having a diameter of 38.4 mm. After that, the mold was opened and the core was taken out. Such molding was repeated, and the number of moldings until the core could not be taken out from the mold was counted. The results are shown in Table 1 below.

[0068]

[Table 1]

As shown in Table 1, in the mold provided with the mold release layer obtained by the composite gold plating, good mold releasability is maintained for a long time. From this evaluation result, the superiority of the present invention is clear.

[0070]

As described above, the mold of the present invention maintains good mold releasability for a long time. The productivity of golf balls is improved by using this mold.
The mold release layer does not adversely affect the physical properties of the golf ball.

[Brief description of drawings]

FIG. 1 is a front view showing a mold according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing a part of a lower mold of the mold of FIG.

FIG. 3 is a flow chart showing an example of a method for manufacturing the mold of FIG.

FIG. 4 is an enlarged cross-sectional view for explaining the manufacturing method of FIG.

FIG. 5 is a schematic diagram for explaining a method of measuring a contact angle.

FIG. 6 is a partially cutaway sectional view showing a golf ball using a core molded by the mold of FIG.

[Explanation of symbols]

1 ... Mold 2 ... Upper mold 3 ... Lower mold 4, 5 ... Cavity surface 6 ... Base 7 ... Underlayer 8: Release layer 9 ... First release layer 10 ... Second release layer 11 ... Preliminary composite film 14 ... Core 15 ... golf ball 16 ... Cover 17 ... Main body

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Akihiro Yukawa             2-7-23, Kagino-nishi, Joto-ku, Osaka-shi, Osaka               Limited Protonics Institute F-term (reference) 4F202 AA45 AH61 AJ03 AJ09 AJ11                       CA09 CB01 CD22 CM84

Claims (14)

[Claims] 1. A mold for a golf ball comprising a base and a release layer covering the surface of the base, the release layer comprising gold and a fluorine-containing polymer compound dispersed in the gold. A mold for a golf ball, which is a composite film containing: 2. The golf ball mold according to claim 1, wherein the fluorine-containing polymer compound has a network structure on the surface of the release layer. 3. The golf ball mold according to claim 1, wherein the content of the fluoropolymer compound in the release layer is 15% by volume or more and 40% by volume or less. 4. The release layer has a thickness of 3 μm or more and 15 μm or more.
The golf ball mold according to any one of claims 1 to 3, which is as follows. 5. The mold for a golf ball according to claim 1, wherein the fluorine-based polymer compound is a polymer compound having a perfluoroalkyl group or a polyfluoroalkyl group. 6. The fluorine-based polymer compound is polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride or a tetrafluoroethylene-hexafluoropropylene copolymer, or two or more kinds selected from these. It is a combination 5.
The mold for a golf ball described in. 7. The golf ball mold according to claim 1, wherein a contact angle of water on the surface of the release layer is 100 ° or more and 140 ° or less. 8. The undercoat layer is provided between the base and the release layer, and the undercoat layer is a composite film containing nickel and a fluorine-based polymer compound dispersed in the nickel. The mold for golf balls according to claim 7. 9. The release layer comprises a first release layer formed on the surface of an underlayer and a second release layer formed on the surface of the first release layer. 9. The golf ball mold according to claim 8, wherein the layer is obtained by substituting gold for nickel in a preliminary composite film containing nickel and a fluorine-containing polymer compound dispersed in the nickel. 10. A step of forming a release layer made of a composite film containing gold and a fluorine-containing polymer compound dispersed in the gold on the front side of the base, and the base and the release layer are formed of a fluorine-containing polymer. A method of manufacturing a mold for a golf ball, which comprises a step of performing heat treatment at a temperature equal to or higher than the melting point of the compound. 11. A step of forming a preliminary composite film containing nickel and a fluorine-containing polymer compound dispersed in the nickel on the front side of the base, and replacing nickel in the vicinity of the surface of the preliminary composite film with gold. A step of forming a first release layer, and a step of forming, on the surface of the first release layer, a second release layer formed of a composite film containing gold and a fluorine-containing polymer compound dispersed in the gold. A method for manufacturing a golf ball mold including: 12. A step of molding a main body of a golf ball or a part thereof by a mold having a release layer composed of a composite film containing gold and a fluorine-containing polymer compound dispersed in the gold on the surface thereof. A method of manufacturing a golf ball, including: 13. The method for producing a golf ball according to claim 12, wherein the surface of the molded body molded by the mold is made of a rubber composition containing zinc methacrylate or zinc acrylate. 14. The method of manufacturing a golf ball according to claim 12, wherein the surface of the molded product molded with the mold is made of an ionomer resin composition.