JPS5855793B2 - Bowling ball shell composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bowling ball shell composition comprising an inner core and an outer shell.

The shell composition is coated with a shell made of a styrene-butadiene copolymer and a polyfunctional unsaturated ester, which shortens the molding time and improves impact and repulsion properties compared to conventional shell compositions. The company provides bowling balls that are

Conventional bowling balls have an inner core made of cork, wood flour, rubber powder, etc., hardened and molded using rubber or thermosetting resin as a binder, or an inner core made of hard foamed urethane, and a hard core is molded on the outer peripheral surface of the inner core. Rubber (hereinafter referred to as ebonite)
It is customary to have an outer shell made of polyurethane and heat harden it to form a mold.

Ebonite, which is commonly used as the outer shell, is obtained by subjecting a hard rubber composition to high degree of crosslinking by heating under pressure for a long period of time using a known vulcanization method.

However, when forming ebonite, it has the disadvantage that it requires a long curing time of about 2 hours to about 5 hours at normal molding temperatures (130 to 160° C.).

For lightweight balls (generally less than 10 pounds), it is necessary to reduce the specific gravity of the inner core by increasing the amount of filler such as cork or wood flour, which causes the inner core to be less dense. Weakening physical strength.

In order to improve this, an inner core made of hard urethane foam has also been produced.

However, in balls whose inner core is coated with ebonite, repeated impacts during use create a strain difference between the inner core and the ebonite, eventually causing the outer shell to crack and break.

This is considered to be due to the fact that ebonite as an outer shell has weak physical strength and is brittle.

In addition, lightweight balls in particular are usually used by people with relatively weak physical strength, such as women and children, but lightweight balls made of ebonite have poor repulsion, which means that the repulsion against the bowling pins when pitching is weak. , therefore, had the disadvantage of low scoring ability.

It is an object of the present invention to provide a bowling ball that improves the above-mentioned drawbacks of conventional bowling balls, reduces molding time, has good impact resistance, and has high repulsion.

Of course, the present invention is not limited to lightweight balls, but can also be applied to medium weight edge balls (generally weighing 12 pounds or more).

It is a further object of the present invention to provide a new and improved composition for use in the manufacture of bowling balls, which composition contains at least 65% styrene. Bukdiene copolymer 7
0 parts by weight or more, and 30 to 50 parts by weight of polyfunctional unsaturated ester and 1 to 10 parts by weight of organic peroxide, based on the rubber component mixed with at least 30 parts by weight of at least one type of natural or synthetic rubber or thermoplastic resin. Parts by weight, filler 50-1
20 parts by weight, and 0.5 to 15 parts by weight of pigment.

As components other than those mentioned above, conventional additives such as anti-aging agents, softeners, and processing aids can be appropriately added.

Here, the styrene-butadiene copolymer is a styrene-butadiene copolymer containing at least 65% styrene, and among these, a styrene-butadiene copolymer containing 65 to 90% styrene is preferred.

As natural or synthetic rubber or thermoplastic resin, natural comb, synthetic imprene rubber, styrene/phtadiene rubber, phtadiene rubber, inbutylene/imprene rubber, acrylonitrile/butadiene rubber, chloroprene rubber,
Ethylene/propylene rubber, polyethylene, ethylene/
Vinyl acetate copolymer, acrylonitrile/butadiene/
Examples include styrene copolymers, polyurethanes, and ionomers.

Examples of the polyfunctional unsaturated ester include ethylene glycol dimethacrylate, 1,3-butylene dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, and tetramethylolmethanetetramethacrylate.

These can be used alone or in combination of two or more.

Examples of organic peroxides include dicumyl peroxide,
lauroyl peroxide, benzoyl peroxide, di-t-butylperoxydiiso-propylbenzene,
2.4-dichlorobenzoyl peroxide, 2.5-di-methyl-2,5-di(t-butylperoxy)hexane, n-butyl-4,4-bis(t-butylperoxy)valerate, 1゜1-bis(t-butylperoxy)3.3.5 trimethylcyclohexane, etc. are used.

Fillers include zinc oxide, calcium carbonate, silica, etc.
These include clay, titanium oxide, calcium silicate, barium sulfate, etc.

The shell composition of the present invention can be obtained by uniformly mixing the above-mentioned components using a panburi mixer or a mixing roll.

In the bowling ball of the present invention, about 10 ml of the above-mentioned outer shell composition is applied to the outer peripheral surface of the inner core formed by a known method.
It is obtained by applying the film to a thickness of K to about 20 ml and molding it under pressure and heat in a mold.

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

However, the present invention is not limited to the following examples.

All formulations in the examples are shown in parts by weight (hereinafter simply referred to as parts).

The coefficient of repulsion is the coefficient of rebound from the original height when a bowling ball is freely dropped from a height of 2.0 m onto a steel plate with a thickness of 10 cIfL embedded in concrete, and the impact property is determined in the same way as the measurement of the coefficient of repulsion above. The ball was then allowed to fall freely onto an iron plate to give an impact, and this was repeated until cracks appeared on the surface of the ball, and the number of repetitions was measured.

Examples 1 and 2, Comparative Examples 1 and 2 A bowling ball was produced by applying the composition of the outer shell composition shown in Table 1 to the outer peripheral surface of the inner core and pressurizing and heating it in a mold.

The inner cores used had a weight of 1600 grams and a diameter of 1
95φ hard urethane foam was used.

All of the balls obtained were 8 pound class balls.

The results are shown in Table 1.

Example 1 used ethylene glycol dimethacrylate as the polyfunctional unsaturated ester, and Example 2 used trimethylolpropane trimethacrylate.

Comparative Example 1 was the same as Example 1 except that 80 parts of ethylene glycol dimethacrylate was used, and 15 parts was used in Comparative Example 2, but both amounts were outside the scope of the present invention.

Comparative Example 3 A composition having the outer shell composition shown in Table 1 was prepared in the same manner as in Example 1.

Table 2 shows the results for the 8 pound class balls obtained.

This composition is an example of an ebonite formulation.

* SBR manufactured by Japan Synthetic Rubber Co., Ltd. As is clear from Tables 1 and 2, the bowling ball of the present invention has a short molding time, excellent impact resistance and repulsion, and has an appropriate hardness. .

On the other hand, if there is too much polyfunctional unsaturated ester as in Comparative Example 1, the ball will be too hard and the impact strength will obviously decrease. If it is too small, the hardness will be too soft and the repulsion and impact properties will decrease.

As shown in Comparative Example 3, in the case of the ebonite ball,
The hardness is appropriate, but the impact and repulsion properties are poor.

Moreover, a long molding time is required. Example 3 The inner core was made of ebonite whose weight was adjusted with cork and wood flour, and had the same outer shell composition as in Example 1, except that it had a weight of 3050 grams and a diameter of 190φ.

The ball obtained was 13 pound class, and the results are shown in Table 3.
It was shown to.

Comparative Example 4 A sample was prepared in the same manner as in Comparative Example 3, except that the same inner core as in Example 3 was used.

Table 3 shows the results for the 13 pound class balls obtained.

13 by changing the material and weight of the inner core as shown in Table 3.
A pound-class ball was prepared, and the ball of the present invention has excellent repulsion and impact resistance, and has appropriate hardness.

As shown in Table 4, balls were produced using the shell formulations of Examples 4 and 5 and Comparative Example 5 under conditions of a molding temperature of 150° C. and a molding time of 50 minutes.

Examples 4 and 5 are cases where 10 parts of the styrene-butadiene copolymer (styrene content: 65%) was replaced with SBR or ABS resin.

Comparative Example 5 is a case other than the present invention in which 40 parts of 5BR was replaced.

Table 4 shows the results for the balls obtained.

* ABS resin manufactured by Japan Synthetic Rubber Co., Ltd. As shown in Table 4, even if a part of the styrene-butadiene copolymer (styrene content 65%) is replaced with SBR or ABS resin, it has excellent repulsion and impact resistance, and has low hardness. is also appropriate.

Comparative Example 5 in Table 4 clearly has too low hardness and poor repulsion.

As described above, by using the Pauling shell composition according to the present invention, the bowling ball shell composition can maintain appropriate repulsion and hardness, and is particularly suitable for lightweight bowling balls.

Claims (1)

[Claims] 1 A bowling ball consisting of an inner core and an outer shell, the outer shell being made of styrene with a styrene content of 65% or more.
30 parts by weight of a polyfunctional unsaturated ester per 100 parts by weight of a rubber component, which is a mixture of 70 parts by weight or more of a butadiene copolymer and 30 parts by weight or less of one or more substances of natural rubber, synthetic rubber, or thermoplastic resin. 50 parts by weight of a bowling ball shell composition comprising a filler and a pigment, and 1 to 10 parts by weight of an organic peroxide.