JP3351622B2 - Solid golf ball and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Solid golf balls are roughly classified into:
There are one-piece solid golf balls and two-piece or more solid golf balls.

[0003] First, a one-piece solid golf ball will be described. A one-piece solid golf ball is obtained by painting a paint on the surface of a ball body portion formed of a vulcanized molded product of a rubber composition. Although used as a ball, this one-piece solid golf ball has conventionally been manufactured as described below.

First, a rubber composition prepared to have physical properties suitable for a one-piece solid golf ball is formed into a rod shape using an extruder or the like, and then filled into a vulcanization mold. Suitably cut into cylindrical bodies called plugs.

[0005] Next, the obtained plugs are immersed in a water-dispersed fluorine-based release agent so that they do not adhere to each other. At this time, the fluorine-based release agent used generally contains silicon in order to improve the slipperiness of the plug and improve the workability when arranging the plugs in the mold.

The plug immersed in the above-mentioned silicon-containing fluorine-based release agent is filled in a ball-forming mold and vulcanized by a heat treatment under pressure.

[0007] Ball after vulcanization molding (ball body portion)
Is to remove the silicon-containing fluorine release agent adhering to the ball surface by polishing the ball surface using a vibrating barrel, wash it with alcohol, etc., paint it, and paint it as a one-piece solid product Finished as a golf ball.

When the ball is vulcanized and formed by the above method, the plug may be bent. If the plug is formed in a bent state, the bent portion may bite the fluorine-based release agent. Because of this, the rubber compositions do not adhere to each other, and after finishing as a one-piece solid golf ball, cracking occurs when the ball is hit two or three times.

Further, when a fold (fold) is formed on the cut surface during the production of the plug, the portion is entrapped with the fluorine-based release agent, so that the adhesion between the rubber compositions at the portion is hindered, and the plug is manufactured. The surface of the later one-piece solid golf ball will be scratched.

[0010] However, a golf ball driving range recently called a “hitting ground” has been made very clean as compared with before, and it is desired that the one-piece solid golf ball used there be also beautiful. , If there is a visible scratch on the ball surface,
The merchandise value is significantly reduced and cannot be handled as a merchandise.

[0011] Further, if cracks occur at the time of hitting, there is a risk of causing harm to those who are practicing around them, so that the reliability as a golf ball is lacking and the commercial value is significantly reduced.

Further, in a one-piece solid golf ball manufactured by immersing a plug in the above-described fluorine-based release agent, all the fluorine-based release agent adhering to the ball surface at the time of surface treatment using a vibration barrel is removed. After that, when paint was painted on the ball surface,
The adhesion between the paint and the substrate is poor, and the paint peels off from the substrate when hit or immersed, resulting in poor appearance.

In addition, recent practice ranges have introduced a high-speed washing machine so that golf balls can be cleaned neatly in a short period of time. If not, there is a problem that the paint is scraped off with a brush, the appearance is deteriorated, and the commercial value is impaired.

Next, a two-piece or more solid golf ball will be described. A two-piece or more solid golf ball such as a two-piece solid golf ball or a three-piece solid golf ball has a core made of a vulcanized molded product of a rubber composition and a core coated with the core. The core is formed by immersing the core in a fluorine-based release agent and vulcanizing it in the same manner as the ball main body, which is the main component of the one-piece solid golf ball.

Therefore, the same problem as in the above-mentioned one-piece solid golf ball occurs with respect to the core. For example, the adhesion between the cover and the core is reduced due to the fluorine-based release agent remaining on the core surface. When the ball is hit, the cover and the core are separated from each other, resulting in reduced durability and flight performance.

As described above, in a solid golf ball, at least a part thereof is constituted by a vulcanized molded article of a rubber composition. In the production of cores for solid golf balls of two pieces or more such as two-piece solid golf balls and three-piece solid golf balls, the problems caused by the release agent used during vulcanization molding are particularly remarkable in one-piece solid golf balls. And solving the problem in the one-piece solid golf ball, the problem in the two-piece or more solid golf ball is also solved. In this specification, the one-piece solid golf ball will be mainly described.

[0017]

As described above, a conventional solid golf ball, particularly a one-piece solid golf ball, suffers from scratches and cracks on the basis of the fluorine-based release agent used in the production thereof, and also suffers from paint damage. However, there was a problem that it peeled off from the substrate.

Therefore, according to the present invention, the surface of the ball is free from scratches and the adhesion between the paint and the substrate is good.
It is an object of the present invention to provide a solid golf ball in which the appearance is not deteriorated due to peeling of paint even when used for a long period of time, and further, even when the plug is bent and vulcanized and formed, a crack due to a hit ball does not occur. .

[0019]

SUMMARY OF THE INVENTION The present invention provides a conventional one-piece solid golf golf club by immersing an unvulcanized rubber composition in an aqueous dispersion containing a long-chain aliphatic carboxylate, followed by vulcanization molding. Achieved the above object by obtaining a one-piece solid golf ball that does not cause scratches on the ball surface due to the release agent as seen in the ball, decreases the adhesion between the paint and the base, and does not crack on hitting It was done.

Examples of the long-chain aliphatic carboxylate include zinc stearate, magnesium stearate,
Examples thereof include calcium stearate and stearyl amide, and particularly preferred are zinc stearate and magnesium stearate.

When the plug is immersed in an aqueous dispersion of the long-chain aliphatic carboxylate and dried, the long-chain aliphatic carboxylate adheres as particles to the surface of the plug to prevent the plugs from adhering to each other. And improve the slip of the plug. Also,
The long-chain aliphatic carboxylate melts during vulcanization molding and penetrates into the rubber composition, so that even if it adheres to the folds or bends of the plug, it will prevent adhesion between the rubber compositions. Since no ball is present, no scratches are generated on the ball surface due to the release agent, and no cracks are generated due to the release agent biting into the bent portion. In addition, since the long-chain aliphatic carboxylate does not hinder the adhesion of the paint to the substrate, the adhesion between the paint and the substrate is also kept good.

Therefore, in the vulcanization molding, the one-piece solid golf ball using the long-chain aliphatic carboxylate has no scratch on the ball surface, has a beautiful appearance, and has high adhesion between the paint and the base material. Even when washed with a strong brush, the paint does not peel off, and even if the plug is bent during vulcanization molding and vulcanized with the long-chain aliphatic carboxylate bitten, it is cracked by hitting. Does not occur.

The above-mentioned long-chain aliphatic carboxylate is dissolved in water at a concentration of 0.1%.
It is preferable to disperse 5 to 10% by weight, especially 1 to 5
It is preferable to disperse by weight%. That is, when the dispersion concentration of the long-chain aliphatic carboxylate in water is lower than the above range, the adhesion preventing property of the unvulcanized rubber composition is not sufficiently exhibited, and therefore, the plugs stick together. ,
On the other hand, if the dispersion concentration of the long-chain aliphatic carboxylate is higher than the above range, the ball after vulcanization tends to stick to the mold, and the workability is reduced.

As a method for dispersing the long-chain aliphatic carboxylate into water, the long-chain aliphatic carboxylate may be dispersed mechanically using a stirrer or the like, or chemically dispersed using a surfactant or the like. Is also good.

Next, a method for producing a one-piece solid golf ball using the above long-chain aliphatic carboxylate in vulcanization molding will be described, for example, as follows.

First, an unvulcanized rubber composition is extruded into a rod shape using an extruder, and cut into a predetermined size to form a cylindrical body called a plug. Immerse in an aqueous dispersion of carboxylate.

The immersion may be performed at room temperature, but may be performed at an elevated temperature.
The immersion time may be about 1 to 60 seconds, and the effect is hardly increased even if the immersion time is longer than that.

After immersion, the plugs do not adhere to each other, so they may be kept in the same container until they are placed in a mold. Also, since they have good slipperiness, the work for arranging the plugs in the mold is good. Good nature.

The plug after immersion is moved and dried on a belt conveyor, arranged in a container, and transferred to a mold for vulcanization molding.

In the vulcanization molding, the plugs are arranged on a lower mold of a mold, covered with an upper mold from above, and vulcanized by heating under pressure.

After vulcanization, the ball is polished with a vibration barrel to remove long-chain aliphatic carboxylate adhering to the ball surface, washed with water or alcohol, dried, and then painted. To make a one-piece solid golf ball as a product.

At the time of the vulcanization molding, dimples are formed on the ball surface if desired, and marking is performed after paint painting if desired.

Also, a two-piece solid golf ball,
In a two-piece or more solid golf ball such as a three-piece solid golf ball, the core is vulcanized through the same process as the ball body portion of the one-piece solid golf ball, and after the vulcanization, the core is polished with a vibration barrel. Then, by a conventional method, a cover coating on the core,
Alternatively, an intermediate rubber layer is formed and the cover is coated, and the paint is applied to finish. Then, dimple formation and marking are performed as desired.

[0034]

According to the present invention, there is no damage on the ball surface, the appearance is beautiful, the adhesion between the paint and the base is high, and the paint does not peel off even after long-term use. Provided is a one-piece solid golf ball which is free from cracking by hitting a ball even when vulcanization is performed in a bent state during vulcanization.

When the present invention is applied to a two-piece solid golf ball, there is provided a two-piece solid golf ball having high adhesion between a cover and a core and free from defects such as folds or bends of a plug. When applied to a three-piece solid golf ball, a three-piece solid golf ball having high adhesion between the core and the intermediate rubber layer and free from defects such as folds of the plug and bending of the plug is provided.

[0036]

Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

Examples 1 to 6 and Comparative Examples 1 to 8 First, a rubber composition for a one-piece solid golf ball having the following composition was prepared, and the obtained rubber composition was extruded into a rod shape by an extruder, and 48 g of the rubber composition was extruded. Into a plug, and immerse each plug in the immersion liquid shown below to produce a one-piece solid golf ball as shown below, workability during the production and the produced one-piece solid golf ball. The characteristics of the golf ball were evaluated by the following evaluation methods 1 to 5.

Formulation of rubber composition for one-piece solid golf ball 100 parts by weight of high cis polybutadiene 23 parts by weight of zinc oxide 24 parts by weight of methacrylic acid 1.5 parts by weight of dicumyl peroxide

Immersion Liquid A Aqueous dispersion having a zinc stearate concentration of 0.5 to 10% by weight A-1 Zinc stearate concentration 0.5% by weight A-2 Zinc stearate concentration 1.0% by weight A-3 Zinc stearate concentration 3.0% by weight A-4 Zinc stearate concentration 5.0% by weight A-5 Zinc stearate concentration 8.0% by weight A-6 Zinc stearate concentration 10.0% by weight

B: A silicon-containing fluorine-based release agent diluted with water 5 to 20 times (Daifree ME413, trade name, manufactured by Daikin Co., Ltd., containing 0.94% by weight of a fluorine-based compound and 1.8 of a silicon-based compound) B-1 dilution ratio 5 times B-2 dilution ratio 10 times B-3 dilution ratio 15 times B-4 dilution ratio 20 times

C: A fluorine-based release agent diluted with water 5 to 20 times (NOX FREE F-100E, trade name, NOK)
(Ingredients: 0.75% by weight of fluorine-based compound, 2.0% by weight of silicon-based compound) C-1 dilution ratio 5 times C-2 dilution ratio 10 times C-3 dilution ratio 15 times C-4 dilution ratio 20 times

The above A-1 to A-6, B-1 to B-
4. The plug is immersed in the immersion liquid of C-1 to C-4 at room temperature for 30 seconds.

For both upper and lower dies, a die-free ME413 (trade name, previously described) diluted 5 times with water is applied to the molding surface (the surface where the plug contacts) and dried. Keep it.

Thereafter, the plugs immersed in the above-mentioned immersion liquid are arranged on the lower mold of the mold, and the upper mold is put on the plug to cover the lower part of the mold.
The composition is vulcanized at 160 ° C. for 30 minutes under a pressure of g / cm ² .

After vulcanization molding, the ball is polished for 30 minutes with a vibration barrel, washed with alcohol, painted with white paint, and finished into a one-piece solid golf ball having an outer diameter of 42.7 mm.

The workability during the manufacturing process of the one-piece golf ball and the characteristics of the manufactured one-piece golf ball are evaluated by the following evaluation methods 1 to 5.

Evaluation method 1: The ball after vulcanization molding is manually removed from the mold. The response at the time of removal is evaluated based on the following criteria. ：: Can be taken out lightly. △: Can be taken out by applying force. ×: Cannot be taken out.

Evaluation method 2: Ten plugs each immersed in the immersion liquid are placed in a container, and the container is shaken up, down, left and right for one minute. Thereafter, the plug is transferred from the container to the dish, and the plug on the dish is observed and evaluated according to the following criteria.

A: All of the ten plugs have no sticking and are separated. ：: Two or three plugs are stuck, but can be easily removed by hand. Δ: Most of the plugs are attached, but can be easily removed by hand. ×: Most plugs are stuck and cannot be easily removed by hand.

Evaluation method 3: Each of the manufactured one-piece solid golf balls is visually inspected for 1000 pieces, and the occurrence rate of balls having scratches that can be visually confirmed is determined, and the rate is indicated according to the following evaluation criteria.

◎: 0% ○: More than 0% and 1% or less Δ: More than 1% and 3% or less ×: More than 3%

Evaluation method 4: The manufactured one-piece solid golf ball was immersed in water for one week, placed in a container having a brush on the inside, rotated at 250 rpm, taken out, and observed for surface condition. Evaluate according to the following criteria.

A: Paint is not completely removed. ：: Peeling of paint can be confirmed with a magnifying glass of 10 times. Δ: Peeling of the paint can be confirmed visually. ×: Peeling of paint can be confirmed visually at several places.

Evaluation method 5: During vulcanization molding, the plug is intentionally bent to perform vulcanization molding, and thereafter, a one-piece solid golf ball is manufactured in the same manner as described above.

The one-piece solid golf ball manufactured as described above was hit 100 times at a head speed of 45 m / s with a No. 1 wood club using a swing robot manufactured by True Temper Co., Ltd., and the durability against cracking was evaluated according to the following criteria. To evaluate.

A: No cracking even after hitting 100 times. ：: Cracks occur after 50 to 99 hits. Δ: Cracks occur after 10 to 49 hits. ×: Cracks are generated by hitting 5 to 9 times. XX: Cracks occur after one to four impacts.

The above evaluation results are shown in Tables 1 to 3. Table 1 shows the evaluation results when an aqueous dispersion of zinc stearate was used as the immersion liquid, and Table 2 shows the evaluation results when a conventional silicon-containing fluorine-based release agent was used as the immersion liquid. Table 3 shows the evaluation results when another type of silicon-containing fluorine-based release agent was used as the immersion liquid.

[0058]

[Table 1]

[0059]

[Table 2]

[0060]

[Table 3]

As is clear from the results shown in Table 1, in Examples 1 to 6 of the present invention, good evaluation results were obtained by any of the evaluation methods.

That is, in the evaluation method 1, the removability of the ball after vulcanization molding was examined from the mold, and in the evaluation method 2, the prevention of adhesion between the plugs was examined. In each case, good evaluation results were obtained, and workability during production was good.

In the evaluation method 3, the presence or absence of scratches on the ball surface of the manufactured one-piece solid golf ball is examined. In the evaluation method 4, the adhesion between the paint and the substrate is examined. In the evaluation method 5, the plug is bent. Inspection of cracking of a ball by hitting when vulcanization molding was performed in a state where a mold release agent or the like was bitten in the portion, Examples 1 to 6 of the present invention
Shows that the evaluation results are good in any of the evaluation methods, there is no scratch on the ball surface, therefore the appearance is beautiful, the adhesion between the paint and the base material is good, and the paint does not peel off even after long-term use. And no cracking of the ball due to the bite of zinc stearate occurred.

On the other hand, in Comparative Examples 1 to 4 using a silicon-containing fluorine-based release agent, as shown in Table 2, Comparative Examples 1 and 10 which were most commonly used in the past and were diluted 5 times were used.
In Comparative Example 2 of double dilution, although evaluation methods 1 and 2 relating to workability were good, scratches were observed on the ball surface,
Adhesion between the paint and the substrate was poor, and cracks occurred due to biting of the release agent. In Comparative Examples 3 and 4 in which the dilution ratio was increased, workability was reduced.

Similarly, Comparative Examples 5 to 8 using other types of silicon-containing fluorine-based release agents also showed the same tendency as Comparative Examples 1 to 4 according to the dilution ratio, showing good results. Was not obtained, and the workability was lower than in Comparative Examples 1 to 4.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) A63B 37/00

Claims (3)

(57) [Claims] 1. A solid golf ball at least partially composed of a vulcanized molded article of a rubber composition, wherein the vulcanized molded article of the rubber composition is obtained by converting an unvulcanized rubber composition to a long-chain aliphatic carboxylic acid. A solid golf ball formed by vulcanization through a step of immersion in an aqueous dispersion of salt. 2. In producing a solid golf ball at least partially composed of a vulcanized molded article of a rubber composition,
A method for producing a solid golf ball, comprising immersing an unvulcanized rubber composition in an aqueous dispersion of a long-chain aliphatic carboxylate, followed by vulcanization to form a vulcanized molded product. 3. An aqueous dispersion of a long-chain aliphatic carboxylate,
3. The method for producing a solid golf ball according to claim 2, comprising 0.5 to 10% by weight of a long-chain aliphatic carboxylate.