JPH0523403A - Metallic mold for molding golf ball and production of golf ball by using this metallic mold - Google Patents

Abstract

PURPOSE:To well part a golf ball from the metallic mold and to allow molding with high accuracy by forming a chromium oxide film on the surface of the cavity of the metallic mold body for molding the golf ball and coating the film surface with a fluororesin. CONSTITUTION:The chromium oxide film 2 is formed on the surface of the cavity of the metallic mold body 1 formed of iron, copper alloy, etc., by an electrocasting method, high precision method, etc. The film 2 can be formed by black chrome plating, electrochromating, etc. The film 2 surface is then coated with the fluororesin to form a mold parting film 4 consisting of the chromium oxide film 2 and the fluororesin coating layer 3. The fluororesin is adequately tetrafluoroethylene/hexafluoropropylene copolymer, polytetrafluoroethylene, etc. The film 2 surface is coated with the powder or dispersion of the fluororesin, by which the adhesion by baking is improved. The good mold parting property is imparted to the metallic mold in this way and the deterioration in accuracy, sphericity, etc., is obviated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for molding a golf ball having a mold-releasing film formed of a fluororesin on the surface of a cavity and a method for manufacturing a golf ball using the mold.

[0002]

2. Description of the Related Art Conventionally, when molding a golf ball by compression, a resin having a poor releasability is used, so that the molded golf ball cannot be easily released from the mold. Alternatively, the following method is adopted for the purpose of imparting releasability to the molded body itself. (1) A method of spraying a mold release agent such as silicone oil onto the cavity surface of the mold. (2) A method of dipping a mold release agent on a preformed product of a golf ball and then subjecting it to molding by a mold. (3) A method in which a release agent is kneaded into a golf ball molding resin and is used for molding.

[0003]

However, each of the above methods has the following problems. That is, (1)
The method of is a widely used general method, but in this case the release agent may be caught in the resin of the molded product during molding, resulting in defective products, and on the surface of the molded product after molding. It is necessary to wash and remove the attached mold release agent, and the mold release agent has to be sprayed every time molding is performed once, which has a drawback that the molding operation is complicated.

In addition, the method (2) has many steps before molding such as a step of manufacturing a preformed product before molding, a step of dipping a release agent on the preformed product, and the same as the method (1). After the molding, it is necessary to wash and remove the release agent attached to the surface of the molded product, which makes the manufacturing process very complicated.

Further, in the method (3), sufficient mold releasability cannot be obtained only by kneading the mold release agent into the resin, and other mold release methods such as spraying the mold release agent on the mold are eventually obtained. We must take measures to impart sexuality.

The present invention has been made in view of the above circumstances, and has a mold releasing property and a mold for molding a golf ball capable of molding a golf ball with good workability, and an efficiency using the mold. An object is to provide a method for manufacturing a golf ball well.

[0007]

MEANS TO SOLVE THE PROBLEMS As a result of intensive studies to achieve the above object, the present inventor has found that tetrafluoroethylene / hexafluoropropylene copolymer is added to the cavity surface of a golf ball molding die. Coalescence (FE
P), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE) and other fluororesin forming a release film with good adhesion, thereby providing good release properties. It can be applied to the mold, and there is no need to remove the mold release agent after molding, so there is no inconvenience such as complicating the molding process, and there is no deterioration in dimple accuracy or sphericity. We succeeded in molding the ball efficiently.

That is, a chromium oxide film is formed on the surface of the cavity of the mold by an electrolytic method such as black chromium plating, electrolytic chromate, and anodic oxidation of chromium. It is possible to form a fluororesin film on the mold surface with good adhesion, and thus to form a mold release film having a thickness of 30 μm or less that hardly deteriorates the accuracy of the mold and which can impart good mold release properties. In addition, this release film has excellent durability, and after removing the fluororesin, the chromium oxide film can be easily removed by acid cleaning, and the release film can be removed without damaging the mold. Since the mold film can be regenerated and the mold body is not physically damaged, it was found that the mold body can be used semipermanently, and the present invention has been completed.

Therefore, according to the present invention, a chromium oxide film is formed on the surface of a cavity of a golf ball molding die body,
The present invention provides a mold for molding a golf ball, characterized by coating the film with a fluororesin, and a method for manufacturing a golf ball, which comprises molding using this mold.

The reason why the fluororesin film can be formed on the chromium oxide film with good adhesion is not clear, but it seems that the fluororesin is coordinate-bonded to the chromium oxide film during baking. Further, the chromium oxide film has a microporous surface, microcracks are formed, or fine particles are laminated depending on the type and forming conditions,
It is considered that a part of the fluororesin layer penetrates into these recesses and exerts an anchor effect, which also has a favorable effect on the adhesiveness.

The present invention will be described in more detail below. In the mold for molding a golf ball according to the present invention, as shown in FIG. 1, a chromium oxide film 2 is formed on the surface of a cavity of a mold body 1, By forming the fluororesin coating layer 3 on the chromium oxide film 2, the chromium oxide film 2
And a fluororesin coating layer 3 is formed. In this case, the mold body 1 is made of an iron or copper alloy formed by an electroforming method, a high-precision method, a casting method or the like. Any of those made of stainless steel, nickel, etc. can be used. In addition,
Reference numeral 5 in FIG. 1 denotes a convex portion for forming dimples formed in the cavity of the mold.

In the golf ball molding die of the present invention, a chromium oxide film 2 is first formed on the cavity surface of the die body 1.
To form. In this case, the chromium oxide film 2 can be formed by black chromium plating, electrolytic chromate, anodic oxidation of chromium, or the like. When carrying out these electrolysis methods, there is no limitation on pretreatment of the mold body, formation of a base, etc., but when forming a chromium oxide film on the mold body made of iron or copper alloy, nickel plating is applied to the mold body. It is preferable to form a film and then form a chromium oxide film thereon. In this case, the thickness of the nickel plating film is 1 to
It is preferably about 3 μm.

The composition of the bath for forming the chromium oxide film by cathodic electrolysis such as the above black plating and electrolytic chromate is not particularly limited, and the chromium compound and acetic acid, acetate,
Those containing a catalyst such as fluoride or urea and an additive such as nitrate or barium salt are used. More specifically, the baths shown below can be exemplified, but the baths are not limited to these, and the component concentrations in the following compositions can be appropriately changed.

[0014]Composition 1       Chromic anhydride 100-300 g / L       Nickel chloride 10-30g / L       Glacial acetic acid 1-15 ml / L Composition 2       Chromic anhydride 100-300 g / L       Ammonium vanadate 10-30g / L       Acetic acid 1-15 ml / L Composition 3       Chromic anhydride 200-300 g / L       Fluorosilicate 0.1-3 ml / L       Barium carbonate 1-30g / L Composition 4       Chromic anhydride 300-500 g / L       Sodium hydroxide 40-120g / L       Barium carbonate 3-20g / L       Sucrose 0.5-8g / L       Calcium hydrofluoric acid 0.5 to 5 ml / L Composition 5       Dichromate 30-100g / L       Chromium sulfate 0.2-3g / L       Hydrofluoric acid 0.05-0.5g / L

The conditions for black chrome plating or electrolytic chromating using the above bath are appropriately selected, but the cathode current density is usually 0.1 to 50 A / dm ² , more preferably ^{20 to} 40 A / dm ² . ² and the bath temperature is −
It is 10 to 25 ° C, particularly 0 to 10 ° C.

Further, as the electrolytic solution used for the anodic oxidation of chromium, an electrolytic solution having a usual composition containing a chromium compound, an acid radical such as sulfuric acid, a catalyst such as fluoride and the like can be used. The electrolytic solution having the composition shown below can be exemplified.

[0017]       Chromic anhydride 150-350 g / L       Sulfuric acid 300-500 g / L       Magnesium fluoride 0.1-5g / L

In this anodic oxidation, an anodic electrolysis treatment and a cathodic electrolysis treatment are alternately performed. In this case, the anodic and cathodic current densities are set to 0.01 to 3 A / dm ² , respectively, and 1 to 60
It is preferable to reverse the anodic electrolysis and the cathodic electrolysis every second. The bath temperature is preferably 40 to 60 ° C.

Here, the formation of the chromium oxide film by cathodic electrolysis can be in the form of microcracks or a fine particle laminate, and such a form can be formed by adjusting the electrolysis conditions and the like. It is preferable. Further, in the case of a chromium anodic oxide film, a chromium oxide film having a microporous form can be obtained by alternately repeating the cathodic electrolysis treatment and the anodic electrolysis treatment on the work.

The thickness of the chromium oxide film layer 2 is not particularly limited, but is preferably 0.01 to 10 μm, more preferably 1 to 3 μm. When it is less than 0.01 μm, good adhesion may not be obtained with the fluororesin film, while when it exceeds 10 μm, the thickness of the release film becomes too thick and the precision of the mold is deteriorated. There are cases.

When the chromium oxide film 2 is formed, the mold is usually pretreated. The pretreatment is to degrease the mold, wash it with water, and acid-activate it. It is not always necessary to perform surface treatment on the surface of the mold, and therefore the chromium oxide film can be formed without degrading the surface accuracy of the mold. In addition, the chromium oxide film is not limited to the above, and may be formed by thermal spraying, PVD, CVD, or the like.

Next, a fluorine resin is coated on the chromium oxide film to form a release film 4 composed of the chromium oxide film layer 2 and the fluorine resin coating layer 3. The fluororesin used in this case is not particularly limited, but tetrafluoroethylene / hexafluoropropylene copolymer (FEP), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PEP)
FA), polytetrafluoroethylene (PTFE), etc. are preferably used, and these fluororesins are coated on the above chromium oxide film by powder or dispersion,
By heating and baking this, the fluororesin coating layer can be formed with good adhesion. The coating and baking conditions can be the usual conditions for fluororesin coating.

The thickness of the fluororesin coating layer 3 is not particularly limited, but is 1 to 30 μm, especially 5 to 10 μm.
It is preferable that the thickness of the release film 4 is 2 to 30 μm, particularly 5 to 10 μm as the release film 4 including the chromium oxide film layer 2 and the fluororesin coating layer 3. When the thickness of the fluororesin coating layer is less than 1 μm, good releasability may not be obtained or durability may be extremely reduced.
If it exceeds 0 μm, the precision of the mold such as the dimple precision may be reduced.

When a golf ball is manufactured using the mold for molding a golf ball of the present invention, a golf ball molding material is filled in the mold of the present invention according to a conventional method, and compression molding is carried out. However, in this case, according to the mold of the present invention, it is not necessary to spray a mold release agent or knead the internal mold release agent into the molding resin each time molding is performed, and furthermore, after molding, the golf ball is washed and separated. There is no need to remove the template.

Further, when the release film is worn by repeated molding, most of the fluororesin layer on the outermost surface is removed by a water jet or the like, and then the chromium oxide film is dissolved and removed by an acid such as hydrochloric acid. By doing so, the mold release film can be chemically peeled off without damaging the mold body, that is, without lowering the accuracy of the mold body, and by again forming the mold release film on the mold body. The mold can be easily regenerated without lowering the accuracy.

[0026]

EXAMPLES The present invention will now be specifically described with reference to examples, but the present invention is not limited to the following examples.

Example 1 A nickel golf ball molding die body was manufactured by electroforming, and the cavity surface of the die body was subjected to the following steps (1) to (9) in sequence. A chromium oxide film layer was formed by the cathodic electrolysis method. (1) Solvent degreasing (2) Washing with water (3) Alkaline degreasing (4) Washing with water (5) Acid activity (6) Washing with water (7) Formation of chromium oxide film by cathodic electrolysis (8) Washing with water (9) Drying (60 ° C) , 30 minutes) The chromium oxide film forming step (7) was performed under the following conditions. Bath composition Chromic anhydride 400 g / L NR-10 (manufactured by Ebara Eugelite Co., Ltd.) 10 g / L NR-20 (manufactured by Ebara Eugelite Co., Ltd.) 9 g / L NR-30 (manufactured by Ebara Eugelite Co., Ltd.) 30 g / L Zero Mist HT-2 (manufactured by Ebara-Udylite Co., Ltd.) 0.4 g / L Cathodic electrolysis condition Bath temperature 18 ° C. Cathode current density 30 A / dm ² Plating time 6 minutes Plating film thickness 1.5 μm

The chromium oxide film formed on the mold body is
It was in the form of a chromium oxide laminate in which microcracks were finely formed.

Then, the mold having the chromium oxide film formed thereon is preheated at 150 ° C. for 30 minutes, and then the FEP dispersion is sprayed onto the chromium oxide film by a spray gun to apply the coating, followed by heating at 380 ° C. for 1 hour. Was baked to form an FEP coating layer, and a mold release film composed of a chromium oxide film and an FEP coating film was formed on the cavity surface of the mold body to complete a golf ball molding mold. The FEP dispersion was applied twice to form a fluororesin film having a thickness of 10 μm.

When a golf ball was molded using the obtained mold for molding a golf ball, good mold releasability was exhibited,
A golf ball with good accuracy could be molded.

Since the fluororesin film was considerably worn out after molding was repeated about 3000 times, most of the fluororesin film on the cavity surface was removed with a water jet, and then the mold was immersed in a 35% hydrochloric acid solution. When the chromium oxide film was dissolved and removed by immersion for a long time, the chromium oxide film layer could be peeled off satisfactorily and completely without damaging the mold body. Then, the mold film was formed again on the cavity surface of the mold body by the above method to regenerate the mold, and the golf ball was molded again,
It was possible to mold a golf ball with good accuracy that was the same as the last time.

[Embodiment 2] The same steps as in (1) to (9) below are sequentially applied to the surface of the cavity of the nickel golf ball molding die body similar to that in Embodiment 1, and the chromium oxidation by the anodic oxidation method is performed. A film layer was formed. (1) Solvent degreasing (2) Washing with water (3) Alkaline degreasing (4) Washing with water (5) Acid activity (6) Washing with water (7) Formation of chromium oxide film by anodizing method (8) Washing with water (9) Drying (60 ° C , 30 minutes) The step (7) of forming the chromium oxide film was performed under the following conditions. Bath composition Chromic anhydride 250 g / L Sulfuric acid 450 g / L Magnesium fluoride 0.5 g / L Electrolysis conditions Bath temperature 50 ° C Current density Minus electrolysis 0.3 A / dm ² and plus electrolysis 0.3 A / dm ² every 1 minute Plating time 30 minutes plating thickness 0.3 μm

The chromium oxide film formed on the mold body is
The film had a high strength with finely formed micropores.

Then, the mold having the chromium oxide film formed thereon is preheated at 150 ° C. for 30 minutes, and then PFA dispersion is sprayed onto the chromium oxide film by a spray gun to apply the coating, followed by heating at 400 ° C. for 1 hour. Was baked to form a PFA coating layer, and a mold release film composed of a chromium oxide film and a PFA coating film was formed on the cavity surface of the mold body to complete the golf ball molding mold. The PFA dispersion was applied twice to obtain a fluororesin film having a film thickness of 10 μm.

A golf ball was molded using the obtained mold for molding a golf ball, and showed good releasing property.
A golf ball with good accuracy could be molded.

Further, after the molding was repeated about 2000 times, the release film was considerably worn out. Therefore, after removing most of the fluororesin film on the cavity surface with a water jet, the mold was immersed in a 35% hydrochloric acid solution to 24%. When the chromium oxide film was dissolved and removed by immersion for a long time, the chromium oxide film could be peeled off satisfactorily and completely without damaging the mold body. Then, a mold releasing film is formed again on the cavity surface of the mold body by the above method, the mold is regenerated, and the golf ball is molded again. I was able to.

[0037]

As described above, according to the mold for molding a golf ball of the present invention, the molded golf ball can be released from the mold satisfactorily, and a mold release agent is sprayed every time molding is performed. In addition, it is not necessary to knead the internal mold release agent into the molding resin, and it is not necessary to wash the golf ball after the molding to remove the mold release agent. Therefore, it is possible to reduce the resources and improve the molding workability. Planned. Moreover, the mold release film can be formed extremely thin on the cavity surface of the mold, which enables high-accuracy molding without degrading the accuracy of the mold body and the durability of the mold release film. It is excellent.
Further, when the release film is worn, it is possible to easily peel off the release film and form a new release film without damaging the mold body. Therefore, the mold body can be used semipermanently. can do.

[Brief description of drawings]

FIG. 1 is a partially enlarged sectional view showing a golf ball molding die according to an embodiment of the present invention.

[Explanation of symbols]

1 Mold main body for golf ball molding 2 Chromium oxide film 3 Fluororesin coating layer 4 Release film 5 Dimple forming protrusion

Claims (2)

[Claims] 1. A golf ball molding die characterized in that a chrome oxide film is formed on the surface of a cavity of a golf ball molding die body, and a fluorine resin is coated on the film. 2. A method of manufacturing a golf ball, which comprises molding using the mold according to claim 1.