JPS60258236A - Rubber composition - Google Patents

Abstract

PURPOSE:A rubber composition that is composed of a specific silicone rubber, a specific polybutadiene rubber, a hardness regulator, a weight regulator and a curing agent, thus giving golf balls guaranteeing long carries with high impact resilience. CONSTITUTION:The rubber component containing (A) 4-100wt% of a silicone rubber of more than 800 polymerization degree based on siloxane units and (B) 96-0wt% of polybutadiene rubber which has more than 30 of Mooney viscosity and more than 40% of cis-1,4-bonds, is combined with (C) a hardness regulator, (D) a weight regulator and (E) a curing agent. Component A used includes 0.1- 100%, preferably 5-35% of vinyl group based on the whole side chains.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rubber composition having high repulsion elasticity, and more particularly to a rubber composition suitable for use in manufacturing golf balls.

In general, golf balls are one-piece golf balls made of a single constituent material, two-piece golf balls made of a core material covered with a cover material, and two-piece golf balls made of a core material covered with a cover material. The ball is further divided into wound golf balls, which are made by covering the ball with a cover material. However, in manufacturing any of these golf balls, it is necessary that the central core material has high rebound resiliency.

Conventionally, rubber compositions with high repulsion properties mainly made of polybutadiene rubber have been used as rubber materials for golf balls, and by making various improvements to these rubber compositions, it has been possible to increase the flight distance of golf balls. However, using only polybutadiene rubber as the rubber component has a certain limit in increasing flight distance.

In view of the above circumstances, the present inventors conducted intensive studies to obtain a rubber composition with high repulsion that guarantees a long flight distance when used in golf balls, and found that the degree of polymerization of siloxane units was It has been found that a silicone rubber having a molecular weight of 800 or higher has a higher rebound resilience suitable for use in golf balls than polybutadiene rubber, and a silicone rubber having a polymerization degree of 800 or higher in siloxane units of 4 to 100%. (wt%, same hereinafter) and Mooney viscosity of 30 or more and cis-1,4 in the total polymer unit.
- Polybutadiene rubber 96-0 with a bond of 40% or more
When a crosslinked rubber composition obtained by blending a hardness modifier, a weight modifier, and a curing agent with a rubber component consisting of has excellent repulsion properties,
It was discovered that the flight distance was significantly increased compared to a golf ball using only polybutadiene rubber as the rubber component. It has been discovered that by combining the rubber compositions, the impact resilience can be improved, and that this rubber composition can be effectively used in golf balls, balls, and other members that require high impact resilience or low energy loss, and have developed the present invention. This is what led to the eggplant.

The present invention will be explained in more detail below.

The rubber composition of the present invention has a polymerization degree of siloxane units of 80.
4 to 100% of silicone rubber having a molecular weight of 0 or more and 96 to 0% of a polybutadiene rubber having a Mooney viscosity (ML1+4) of 30 or higher and having a cis-1,4-bond in the total polymer unit of 40% or higher. It is made by blending a hardness adjuster, a weight adjuster, and a curing agent with a rubber component.

Here, in the rubber component, the silicone rubber must have a degree of polymerization of siloxane units of at least 800,
It is preferably 6,000 or more, more preferably 9,500 or more. If the degree of polymerization is less than 800, sufficient compatibility with rubbers other than silicone rubber, such as polybutadiene rubber, will not be obtained, which is not preferable.

Further, the silicone rubber used in the present invention is represented by the general formula, and out of the total amount of side chain R, 1:
It is preferable that vinyl groups account for 0.1 to 100%, more preferably 1 to 50%, and particularly desirably 5 to 35%. If the vinyl group is less than 0.1% based on the total amount of side chains, a sufficient network structure cannot be formed.
As a result, the rubber composition may not exhibit sufficient impact resilience.

Further, most of the functional groups other than vinyl groups are preferably methyl groups, but phenyl groups or trifluoroethyl groups may be present in an amount not exceeding 5% of the total amount of side chains R. However, if the phenyl group or trifluoroethyl group is present in an amount of 5% or more based on the total amount of side chains, the glass transition temperature of the silicone rubber will be significantly increased, and as a result, the rubber composition will not exhibit sufficient impact resilience. It may disappear. Note that the silicone rubber described above is preferably of a heat-crosslinking type.

In the present invention, the content of silicone rubber in the rubber component is 4 to 100%, particularly preferably 5 to 40%.

The polybutadiene rubber that can be blended with the silicone rubber has a Mooney viscosity (M, L 1'+ 4 ) of
With 0 Lotto, IQU size 1. /L dimension is preferably 44 or more, more preferably 60 or more. Further, it is desirable that 1276940% or more of the total polymer, preferably 85% or more, more preferably 90% or more, particularly preferably 93% or more, have a structure of cis-1,4-bonds. When polybutadiene rubber has a Mooney viscosity of less than 30 and a cis-1,4-bond content of less than 40%, the rubber composition does not exhibit 1-minute impact resilience.

In addition, the content of polybutadiene rubber in the rubber component is 96
-0%, particularly preferably 95-60%.

In addition, in the above rubber composition, other rubbers such as polyisoprene rubber, natural rubber, styrene-butadiene rubber, etc. are added in an amount not exceeding 10 parts by weight per 100 parts by weight of the rubber component consisting of silicone rubber and polybutadiene rubber.
NBR, acrylic rubber, chloroprene rubber, chlorosulfur atomized polyethylene, butyl rubber, EPT, thermoplastic elastomer rubber, etc. may be added.

Hardness modifiers include (i) unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, sorbic acid, tiglic acid, silica acid, and aconitic acid; ) Formic acid, acetic acid, benzylic acid, glycolic acid, DL-mandelic acid, thioglycolic acid, tartaric acid, citric acid, DL-malic acid, carbamic acid, adipic acid, alginic acid, azelain W, n
- Saturated carboxylic acids such as acetic acid, n-caproic acid, n-capric acid, and n-caprylic acid; (iii) aromatic carboxylic acids such as benzoic acid, salicylic acid, trimellitic acid, phthalic acid, tannic acid, and tetrachlorophthalic acid; acid, (iV)
N-acetylglycine, β-alanine, DL-asparagine 112, L-glutamine, glycine, L-glutamine III, DL-methio, nin, D-phenylalanine, N-phenylglycine, L-tyrosine, etc.
ml, (V) unsaturated compounds such as allyl alcohol, allyl diallyl phthalate chloride, allyl acetate, diallylamine, benzalacetone, diallyl maleate, (vi)
Derivatives such as esters, lactones, halides, anhydrides, amides, imidolactams, hydrazides, azides, etc. of the compounds described in (:) to (V) above; (vii) derivatives of the compounds described in (i) above;
) to (Vi) and Zn, r'h, CasMa
Modifiers containing metal ions having a valence of 1 to 3, such as Ba, and causing a polymerization reaction during heat curing to increase hardness, are used, and (vii) is particularly preferred.

In addition, as the hardness modifier, one type of these may be used alone or two or more types may be used in combination.

The amount of hardness modifier used is not particularly limited, but rubber component 1
It is preferable to use 5 to 60 parts by weight per 00 parts by weight.

In addition, reinforcing fillers such as carbon black, silica, calcium carbonate, magnesium silicate, and aluminum silicate, as well as phenolic resins, coumaron resins, urea resins, unsaturated polyesters, melamine resins, alkyd resins,
One type of organic filler selected from epoxy resin, polyethylene, vinyl chloride resin, polypropylene, polystyrene, ABS resin, As resin, polyvinyl alcohol, methacrylic resin, petroleum resin, polyamide, vinylidene chloride resin, polycarbonate, fluororesin, etc. Alternatively, two types can be used alone or simultaneously with components (i) to (vii).

Next, when the rubber composition of the present invention is used for a golf ball, the Ifi adjusting agent is used, for example, when the golf ball has a weight of 1 kM.
For golf balls, an appropriate amount is added to make the specific gravity of the crosslinked rubber composition 1.0 to 1.5. In this case, the weight adjusters include zinc oxide, barium sulfate, alumina, calcium sulfate, aluminum sulfate, molybdenum disulfide, calcium carbonate, aluminum silicate, magnesium silicate, graphite, metal powder,
[Sand, pumice powder, slate powder, mica powder, asbestos,
Examples include glass bulbs, and those having a specific gravity of 1.5 or more are particularly preferably used. These weight adjusters can be used alone or in combination of two or more.

In addition, as curing agents, tert-butyl hydroperoxide, cumene hydroperoxide, di-tert-butyl peroxide, tert-butyl cumyl peroxide, 2,
5-dimethyl-2,5-di(tert-butyl peroxy)
Hexane, 2,5-dimethyl-2,5-di(tert-butyl peroxy)hexyne-3-dicumyl peroxide, benzoyl peroxide, tert-butyl peroxy isopropyl carbonate, 1,1-bis(tert-butyl peroxy) butyl peroxy)-3,3,5-trimethyl cyclohexane, 2,4-dichlorobenzoyl peroxide, 1,3-bis(tert-butyl peroxy isopropyl)benzene, tert-butyl peroxy benzoate, p- Organic peroxides such as chlorobenzoyl peroxide, n-butyl-4,4-bis' (tert-butyl peroxy) valerate, tert-butyl perbenzoate, sulfur, resin vulcanizing agents (quinone dioxime, phenols) Among these curing agents, organic peroxide compounds are preferably used.

The amount of these curing agents used is also not limited, but is 0.2 to 10 parts by weight, preferably 0.4 to 4 parts by weight, and more preferably 0.6 to 1.6 parts by weight based on 100 parts by weight of the above rubber component. It is desirable to make it a department.

In addition to the hardness adjuster, weight adjuster, and curing agent described above, an anti-aging agent and the like may be added if necessary. Here, the anti-aging agents include naphthylamine-based, diphenylamine-based, p-phenylenediamine-based, quinoline-based, monophenol-based, bisphenol-based,
Commonly used anti-aging agents for rubber compositions such as trisphenols, polyphenols, thiobisphenols, hydroquinone derivatives, and waxes may be used.

The rubber composition of the present invention has a temperature of 20 to 3
Crosslinking is achieved by heating for 0 minutes.

In this case, the above rubber components, hardness modifier, weight modifier,
When obtaining a crosslinked rubber composition by crosslinking a rubber composition made of a curing agent, the ingredients, crosslinking conditions, etc. are selected to have appropriate properties depending on the intended use. When used as a core material, its JISA hardness is 80 to 97, more preferably 85 to 95.
It is desirable that the specific gravity is in the range of 1.0 to 1.5. If the hardness is less than 80,
The core material of a golf ball using the above-mentioned cross-linked rubber composition is deformed when a thin elastic band is wrapped around it and when the cover material is coated. This may result in a loss of feeling.

As explained above, the rubber composition of the present invention is a silicone rubber having a degree of polymerization of siloxane units of 800 or more.
00% and a polybutadiene rubber with a Mooney viscosity of 30 or more and cis-1,4-bonds in the total polymer unit of 40% or more The crosslinked rubber composition of the present invention exhibits excellent high impact resilience and is therefore suitable for golf ball materials, especially co-curing agents, as described above.
.

Not only is it suitable for use in materials such as tennis and baseball balls, toys, Zydewalls for fuel-efficient tires, shoes, rubber springs, etc., but it is also effective in materials that require high repulsion or low energy loss. It can be used for

As mentioned above, the rubber composition according to the present invention is suitably used for golf balls and can increase the flight distance of golf balls. Core material 1.
It is effectively used as a one-piece pole material and a core material for wound golf balls. When manufacturing a two-piece pole or the like, the core is covered with a cover, and the cover material is preferably an ionomer resin made of a metal salt of a copolymer of ethylene and an unsaturated carboxylic acid. In this case, examples of the unsaturated carboxylic acid include acrylic acid and methacrylic acid, and examples of the metal forming the metal salt include -171 and the like.

EXAMPLES Hereinafter, the present invention will be specifically explained by showing examples and comparative examples, but the present invention is not limited to the following examples.

[Examples and Comparative Examples] Golf balls of Examples and Comparative Examples were manufactured according to the formulations shown in Table 1.

That is, each raw material shown in Table 1 was mixed with a roll having a surface temperature of 40° C. or less to prepare a sheet. Fill this sheet into a mold of an appropriate size, heat it at a temperature of 150°C and for a heating time of 20~
After heat curing for 30 minutes, the mold was demolded. Next, the pole was integrally covered with an ionomer resin cover having a thickness of 2.2 mm to produce a two-piece pole.

Next, the performances of these two-piece poles, such as initial velocity and flight distance, were measured using a golf ball hitting tester.

Table 2 shows the physical properties and performance of each two-piece pole.

Table 1 The proportion of R is 94% for methyl groups and 6% for vinyl groups.

*2: Mooney viscosity 44, cis-containing @95% was used.

Table 2 *3: Initial velocity of the ball when hit at a head speed of 481 m/s.

*4: Golf ball hitting test II (True Tempe
Flight distance of the ball when hit with a head speed of 45 Ill/S using

As shown in Table 2, it was found that golf balls using the rubber composition of the present invention had improved flight distance.

Applicant Brideston Co., Ltd. Agent: Patent Attorney Takashi Kojima).

Claims (1)

[Claims] 1. Silicone rubber with a degree of polymerization of siloxane units of 800 or more and a Mooney viscosity of 30 or more and 4 to 100% by weight of cis-1,4-bonds in all polymer units.
A rubber composition comprising a rubber component consisting of 96 to 0% by weight of polybutadiene rubber, which is 0% or more, and a hardness modifier, a weight modifier, and a curing agent.