JPH0228940Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a hollow rubber ball for ball games that has excellent flexibility and is suitable for use as a game ball for young people. Conventional hollow rubber balls for this type of ball game are
As shown in Fig. 1, an inner tube 1a whose internal pressure can be adjusted by a valve 3a etc. and a rubber layer 5a for the skin.
Some are constructed with a reinforcing layer 6 made of thread or cotton cloth interposed between them, and others are constructed with only a rubber layer for the outer skin without an inner tube or reinforcing layer.

In the former case, in which the reinforcing layer 6 is interposed, the elasticity of the ball is greatly limited by the presence of the reinforcing layer with poor extensibility, resulting in a lack of flexibility, making it difficult for young people such as school children to play with such balls. The problem was that it was too hard to be used as a golf ball.

In addition, isobutylene-isoprene rubber (IIR) with low air permeability is used for the inner tube 1, and natural rubber or natural rubber and styrene-butadiene rubber (SBR) is used for the skin rubber layer 5a due to cost and workability. Blends were commonly used. In this case, vulcanization adhesion between the inner tube 1 and the skin rubber layer 5a was impossible due to the material, and even if a special adhesive was used, it was difficult to completely integrate the layers. . Therefore, in the past, it was necessary to provide a reinforcing layer 6 to maintain the durability of the ball.

Furthermore, natural rubber and styrene-butadiene rubber (SBR) have very poor weather resistance, and therefore have drawbacks such as rapid deterioration and cracking.

In addition, in the case of the latter, which is composed only of a rubber layer for the skin, it is highly flexible because it does not have a reinforcing layer, but natural rubber or a blend of natural rubber and styrene-butadiene rubber (SBR) is mainly used. However, since the air permeability is high and it is difficult to maintain the internal pressure, and like the former case, the weather resistance is poor, so it deteriorates quickly and cracks occur, making it impossible to maintain the internal pressure.

This invention was made in order to eliminate the drawbacks of the conventional hollow rubber balls for ball games as described above.

An embodiment of this invention will be explained based on FIG.

Reference numeral 1 designates an inner tube forming the inner layer of the ball 2, which is formed into a hollow sphere shape from a rubber material containing 70% or more of isobutylene-isoprene rubber (IIR) with low air permeability, and is equipped with a valve 3 and an insect 4 to control the internal pressure. It is configured so that it can be adjusted.

5 is the rubber layer for the skin, and it is essential that the rubber material contains ethylene-propylene rubber (EPDM), which can be vulcanized and bonded to the above-mentioned IIR and has excellent weather resistance. A blend of EPDM and natural rubber or natural rubber or SBR is considered optimal.

Thus, the skin rubber layer 5 is directly bonded to the inner tube 1 and is completely melted and integrated by means such as vulcanization adhesion.

As mentioned above, in this invention, the inner tube 1 forming the innermost layer of the ball 2 is made of 70% or more isobutylene-isoprene rubber (IIR), and the surface of the inner tube 1 is coated with ethylene-propylene rubber (EPDM), natural rubber, etc. The outer skin rubber layer 5 is a blend of the above and the like and is integrally bonded by means such as direct vulcanization adhesion.

According to this invention, since the inner tube 1 and the skin rubber layer 5 are directly and integrally bonded, a mutual reinforcing effect is exerted, and air retention is extremely good, and the conventional reinforcing layer of cotton cloth etc. can be used. It has significantly better flexibility than an intervening ball, making it suitable for use as a play ball for children.

In addition, since styrene-propylene rubber, which has excellent weather resistance, is used for the skin rubber layer 5, it does not deteriorate quickly and crack like in the past, making it highly durable and inexpensive to manufacture. It has special features.

[Brief explanation of drawings]

FIG. 1 is a vertically cut front view of a conventional hollow rubber ball for ball games, and FIG. 2 is a vertically cut front view of a hollow rubber ball for ball games according to this invention. 1...Inner tube, 2...Ball, 5...
...Rubber layer for the epidermis.

Claims (1)

[Scope of utility model registration request] The inner tube, which forms the inner layer of the ball, is made of 70% or more isobutylene-isoprene rubber, and the skin rubber layer, which is a blend of ethylene-propylene rubber and natural rubber, etc., is directly applied to the surface of the inner tube by vulcanization adhesive, etc. A hollow rubber ball for a ball game, characterized in that the ball is integrally joined by means.