JPS6321076A - Production of liquid center ball for golf ball - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a method for manufacturing a liquid center ball for golf balls, and in particular, a method for efficiently manufacturing a liquid center ball for golf balls of high quality with extremely little variation in product quality. Relating to a method of manufacturing.

[Prior Art] There are two types of core materials for thread-wound golf balls: a liquid core in which a liquid or paste is wrapped in a rubber bag, and a solid rubber core.

Among these, solid centers are easy to manufacture and are relatively inexpensive due to improved and advanced manufacturing methods, and are therefore used as the core material of golf balls for intermediate to advanced golfers.

On the other hand, liquid centers are preferred by top golfers such as professionals and top amateurs due to their good feel when hitting and ease of control. However, although liquid centers have excellent properties in terms of performance, they are difficult to manufacture and have conventionally been used only in the highest quality wound balls.

Conventionally, the following methods are known as methods for manufacturing liquid centers.

■ Put liquid or paste core material into a spherical mold and freeze it at low temperature to make a spherical solid core material. Cover this core material with unvulcanized bag rubber, then put it into a mold and mold it. Sulfurize.

■ Vulcanize and mold two hemispheres of bag rubber, stick them together using adhesive, and vulcanize and mold them again to make a hollow bag. Next, a certain amount of liquid is injected into the bag using a syringe or the like, and the injection site is sealed.

[Problems to be solved by the invention] However, the conventional methods (2) and (3) above both require a large number of steps and are complicated, resulting in high manufacturing costs and the possibility of air remaining in the bag. There is a large variation in product weight. For this reason, in the past, it was necessary to sort the products by weight, and even after 7fL4x sorting, due to the presence of air in the bag, when it was made into golf balls,
There was a risk of variations in flight performance.

[Means for Solving the Problems] The present invention solves the above-mentioned conventional problems and provides a method for manufacturing an inexpensive and high-quality liquid center ball, which comprises: The gist of the present invention is a method for manufacturing a liquid center ball for a golf ball, which comprises applying an adhesive to a golf ball, then bonding the pair of hemispheres together in a liquid material, and then vulcanizing the ball.

The present invention will be explained in detail below with reference to the drawings.

FIGS. 1(a) to 1(e) are cross-sectional views illustrating the manufacturing process of the liquid center ball for golf balls of the present invention.

In the present invention, first, a pair of bag rubber hemispheres 1 are vulcanized and molded using molds 11 and 12 (FIG. 1(a)).

In this case, if the vulcanization time is long, the adhesion during vulcanization molding in the final step becomes poor, and a similar tendency is observed when the vulcanization temperature is high. Therefore, when vulcanizing the hemisphere, it is preferable to set conditions that do not impair the adhesion of the final step of vulcanization, taking into account the bag rubber material, the size of the hemisphere, etc. Further, in this vulcanization molding, it is not preferable to use a mold release agent.

Next, apply the adhesive 2 evenly to the end face (split opening of the hemisphere) 1a of the hemisphere 1 (Fig. 1(b)), and after some open time, attach the pair of hemispheres 1.1' to the liquid center. immersed in liquid material 3, remove air sufficiently, and bond with liquid material 3 filled inside (Fig.
). This allows the hemispheres 1.1' to be bonded and filled with liquid at the same time.

Next, the sphere 4 whose hemisphere 1.1' is joined with adhesive and whose inside is filled with liquid is taken out from the liquid material 3 and placed in the mold 13.
．． By vulcanization molding at step 14 (Fig. 1(d)),
The joint surfaces are treated and sealed to form a liquid center ball 5 (FIG. 1(e)).

In the present invention, the bag rubber is made of ordinary bag rubber for liquid center balls for golf balls, such as natural rubber, butadiene rubber, isoprene rubber, or a mixture of these rubbers. It is used by adding stearic acid, zinc white, oil, sulfur, a vulcanizing agent, etc. to the rubber material.

Further, as the liquid material for the liquid center sealed in the bag rubber, water or ethylene glycol water solution is usually used.

The adhesive used to join the hemispheres of the bag rubber may be any adhesive that has a strong bonding force with the bag rubber material after vulcanization and does not dissolve in the liquid material, for example, a rubber component dissolved in an organic solvent such as toluene. Rubber glue or the like is used.

In addition, in the present invention, the hemisphere of the bag rubber does not necessarily have to be the shape of a hollow sphere divided in half, but may be a quarter hemisphere if a hollow sphere is formed by a pair of combinations. It may also be combined with a 3/4 hemisphere.

In addition, when bonding a pair of bag rubber hemispheres in a liquid material, production efficiency can be improved by installing a suitable holder or the like in the liquid material so that multiple pairs of hemispheres can be bonded at the same time. Can be done.

[Function] Since a pair of bag rubber hemispheres are bonded together in a liquid material, no near remains in the resulting liquid center ball, resulting in a liquid center ball completely filled with the liquid material. For this reason, the variation in product weight is small,
It is also possible to omit weight sorting.

Moreover, the manufacturing method of the present invention simultaneously performs filling of liquid material and bonding of the hemispheres, as well as adhesion of the hemispheres and sealing of the liquid material, so the number of manufacturing steps is extremely small, and production efficiency is improved. , manufacturing costs are significantly reduced.

[Examples] The present invention will be described in more detail with reference to Examples and Comparative Examples below, but the present invention is not limited to the following Examples unless it exceeds the gist thereof.

Example 1 [Manufacture of liquid center ball] A liquid center ball was manufactured by the method of the present invention as shown in FIGS. 1(a) to (e).

That is, first, as shown in FIG. 1(a), an unvulcanized rubber having the following composition was put into a convex mold 11 having an outer diameter of 24 mm and an inner diameter of 28 mm.
Using a concave mold 12, vulcanization molding was performed at 145° C. for 2 minutes to produce a hemisphere 1.1'. Apply rubber 92 of the composition shown below to each end face of the hemisphere 1.1', and after some oven time, add 4% ethylene glycol water.
? 71i3 and bonded. Next, this was taken out and molded into a mold 13 with an inner diameter of 28 mm as shown in FIG. 1(d).
．． The liquid center ball 5 was obtained by vulcanization molding using No. 14 at 145° C. for 6 minutes.

Natural rubber blended with bag rubber: 100 PHR stearic acid 1 Zinc white: 200 // Naphthenic oil = 40 Vulcanization accelerator 1,5 Sulfur 3 Rubber paste blended rubber component/toluene = 1/2 (weight ratio ) Rubber component Natural rubber: 100 PHR Zinc white: 20 Vulcanization accelerator: 1.5 n Sulfur 3 Measure the weight of the obtained liquid center ball to find the average weight, and also calculate its maximum and minimum values. The dispersion was investigated by calculating the difference between the two values. The results are shown in Table 1.

[Manufacture of thread-wound golf ball] A thread-wound golf ball was produced using this liquid center ball in the following manner.

That is, a rubber thread having the following composition was vulcanized at 150° C. for 40 minutes, and then wound around a liquid center ball. Next, a cover (thickness 2.0 mm) with the following composition was attached to this.
By coating and pressure molding at 150°C for 5 minutes, the diameter was 42.7 mm, the average weight was 45.2 g, and the hardness (
A large size ionomer cover-based golf ball of PGA) 90 was manufactured.

Thread rubber composition: cis-1,4-polyisoprene rubber: 50 parts by weight Natural rubber: 50 nol sulfur
: 1 Zinc oxide
=0.6 is vulcanization accelerator: 1,5
// Accelerating aid: 1 Cover composition Ionomer resin (Surlyn ■ 1557 (trade name of DuPont, USA), Shore D hardness 63 degrees) = 100 parts by weight titanium oxide 1 Maximum weight of manufactured thread-wound golf balls and The difference from the minimum value is the first
Shown in the table.

[Performance test of thread-wound golf ball] Regarding this thread-wound golf ball, TrueTempe
A batting test was conducted using a batting robot manufactured by Company R, and the difference between the maximum and minimum estimated flight distances at a head speed of 45 m/sec was determined to examine variations in flight performance. The results are shown in Table 1.

Comparative Example 1 A hemisphere was prepared in the same manner as in Example 1, and after applying a youthful agent to the end face of the two hemispheres, it was placed in a mold with an inner diameter of 28 mm and vulcanized at 145° C. for 6 minutes. A hollow bag was made. A liquid center ball was manufactured by injecting liquid into this hollow bag with a syringe and sealing the injection hole with an adhesive.

The same bag rubber material, adhesive, and liquid center liquid as in Example 1 were used.

The manufactured liquid center balls were examined for weight variations in the same manner as in Example 1, and thread-wound golf balls were similarly prepared and their weight and flight performance were examined for variations.

The results are shown in Table 1.

Comparative Example 2 The liquid material of Liquid Center was placed in a spherical mold with an inner diameter of 24 mm, cooled at -30°C for 1 hour to freeze, and the resulting solid liquid material was covered with a rubber sheet with a thickness of 2.1 mm. A vulcanized liquid center ball was produced. Next, this was thawed at room temperature, put into a mold with an inner diameter of 28 mm, and vulcanized and molded at 145° C. for 6 minutes to produce a liquid center ball.

The bag rubber material and liquid center liquid are the same as Example 1.
The same one was used.

Example 1 Regarding the manufactured liquid center ball
In the same manner as above, variations in weight were investigated, and thread-wound golf balls were similarly prepared and variations in weight and flight performance were investigated.

The results are shown in Table 1.

Table 1 From Table 1, the liquid center ball produced according to the present invention has extremely small variations in weight and is excellent in quality stability. Therefore, it is possible to obtain thread-wound golf balls with good stability in weight and flight performance. It is clear that it can be done.

[Effects of the Invention] As detailed above, the method for manufacturing a liquid center ball for golf balls of the present invention includes applying an adhesive to the end surfaces of a pair of bag rubber hemispheres, and then soaking the pair of hemispheres in a liquid material. This method is characterized by bonding and then vulcanization. (1) Compared to conventional methods, the manufacturing process is significantly reduced.

■ No air remains inside the ball, resulting in less variation in product weight.

It has the following effects.

Therefore, according to the method of the present invention, a liquid center ball of high quality and excellent quality stability can be manufactured with high production efficiency, and it is also possible to reduce the cost of the product. .

[Brief explanation of drawings]

FIGS. 1(a) to 1(e) are cross-sectional views illustrating the manufacturing process of the liquid center ball of the present invention. 1.1'... Hemisphere, 2... Adhesive, 3...
・Liquid material, 5...Liquid center ball. Agent Patent attorney Tsuyoshi Shigeno (a) (d) ¥1 figure (e)

Claims (1)

[Claims] (1) Manufacture of a liquid center ball for golf balls characterized by applying adhesive to the end faces of a pair of bag rubber hemispheres, bonding the pair of hemispheres together in a liquid material, and then vulcanizing them. Method.