JPS62109838A - Rubber composition - Google Patents

Abstract

PURPOSE:A rubber composition, obtained by incorporating a hindered phenolic antioxidant and/or phosphorus based antioxidant with rubber, having improved winding operability and aging resistance and sufficient strength and suitable as rubber yarns for yarn wound golf balls. CONSTITUTION:A rubber composition obtained by incorporating natural rubber and/or synthetic rubber with a hindered phenolic antioxidant, sulfur based antioxidant and/or phosphorus based antioxidant at 1:0.7-2, preferably 1:0.9-1.5wt. ratio of the phenolic antioxidant to the sulfur based antioxidant and 1:1-3, preferably 1:1.2-2wt. ratio of the hindered phenolic antioxidant to the phosphorus based antioxidant. Rubber containing isoprene-butadiene random copolymer is preferred for the rubber and the total amount of the antioxidants to be incorporated is 0.3-3pts.wt. based on 100pts.wt. rubber.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rubber thread, particularly a rubber composition suitable for a thread rubber for wound golf goals.

The thread-wound golf balls currently used in golf consist of a liquid or solid core ball, a highly oriented rubber layer tightly wound over the core ball, and an outer skin covering the core ball. Among them, does rubber thread N increase the rebound elasticity of golf goals? - Various studies are being conducted to improve the rebound properties, as this greatly contributes to extending the flight distance of the ball.

For example, attempts have been made to reduce energy loss during high stretching of rubber thread by using a large amount of low-cis-containing polyisoprene rubber as the rubber component in rubber thread, or by increasing the degree of vulcanization of rubber thread. It is.

However, all of these methods for improving rebound resilience and extending the flight distance of the goal reduce the energy loss during high stretching of the thread rubber, but they also impair the winding workability of the thread rubber. The problem is that the heat resistance of the thread deteriorates and the thread breaks easily due to the heat history during outer skin molding, which has an adverse effect on productivity such as a decrease in the hardness of the goal, and that the aging resistance of the thread rubber also deteriorates. ing.

The present invention has been made in view of the above circumstances, and has a rubber composition suitable for thread rubber for wound golf goals, excellent in winding workability and aging resistance, and having sufficient strength. The present invention provides a rubber composition characterized by blending natural and/or synthetic rubber with a hindered phenolic antioxidant, a sulfur-based antioxidant, and/or a phosphorus-based antioxidant.

To further explain this point, the present inventors have conducted intensive studies to solve the drawbacks of conventional methods, and have found that natural rubber and/or synthetic rubber has a specific antioxidant, that is, a hindered phenolic antioxidant. When used in combination with a sulfur-based antioxidant and/or a phosphorus-based antioxidant, the thread rubber formed from this rubber composition has sufficiently high strength, and its strength at high temperatures is improved, making it suitable for thread-wound golf. It was discovered that when used as a thread rubber, the thread rubber has good winding workability and also has excellent aging resistance, and has led to the present invention.

The present invention will be explained in more detail below.

The rubber composition according to the present invention is a mixture of natural rubber and/or synthetic rubber with a hindered phenolic antioxidant and a sulfur-based antioxidant and/or a phosphorus-based antioxidant. For example, compared to the case where a hindered phenolic antioxidant, a sulfur-based antioxidant, or a phosphorus-based antioxidant is blended into natural rubber or synthetic rubber individually, the strength at room temperature and high temperature, for example, around 100°C, is improved. , which shows excellent elongation effects.

The hindered phenolic antioxidants used in the present invention include 2,6-not-tert-butyl-4-methylphenol, 2,2'-methylenebis(4-ethyl-6
-tart-butylphenol), 2,2'-methylenebis(4-methyl-6-tert-butylphenol)
, 4,4'-butylidene bis(3-methyl-6-tar
(t-butylphenol), etc., and there is no problem in using these IMs or a mixture of two or more thereof.

In addition, examples of sulfur-based antioxidants include dilaurylthiodipropionate, custearylthiosoderopionate,
Examples include simyristylthionopropionate, laurylstearylthionopropionate, custearyl β, and/or thiozoptylate, and these can be used alone or in combination of two or more.

Further, as phosphorus antioxidants, tris(2,4-not-tert-butylphenyl)-7 osphite, tetrakis(2,4-d-tert-butylphenyl)-4,
Examples include 4'-biphenylene phosphonite and triphenyl phosphite, and one type or a mixture of two or more of these can be used.

In this case, in the combination of antioxidants in the present invention, in the case of a combination of a hindered phenolic antioxidant and a sulfur-based antioxidant, the sulfur-based antioxidant is Antioxidant from 0.7 to
2, especially those blended in a ratio of 0.9 to 1.5 are preferred in order to enhance the improvement effect due to the combination of antioxidants. In addition, in the case of a combination of a hindered phenol-based antioxidant and a phosphorus-based antioxidant, the weight ratio of the phosphorus-based antioxidant to 1 of the hindered phenol-based antioxidant is 1 to 3.
A ratio of 1.2 to 2 is particularly preferred in order to enhance the improvement effect. Furthermore, in the case of a combination of a hindered phenolic antioxidant, a sulfur-based antioxidant, and a phosphorus-based antioxidant, the weight ratio of the sulfur-based antioxidant to 1 part of the hindered phenolic antioxidant is agent 0.3-2
, a phosphorus-based antioxidant is preferably blended in a ratio of 0.3 to 2, particularly a sulfur-based antioxidant in a ratio of 0.5 to 1, and a phosphorus-based antioxidant in a ratio of 0.5 to 1. By blending it into a rubber composition in such a proportion, the strength and elongation at room temperature and high temperature after vulcanization can be significantly improved.

Furthermore, the blending amount of the antioxidant, which is a combination of the above-mentioned hindered phenolic antioxidant and sulfur-based antioxidant and/or phosphorus-based antioxidant, is as follows: natural rubber and/or synthetic rubber xoo,! It is preferable to use 0.3 to 3 parts by weight, particularly 0.5 to 1.5 parts by weight, to part ffi. In this case, if the blending amount is less than 0.3 g/part, the effect of improving strength, thread winding workability, aging resistance, etc. may not be sufficiently exhibited, and if the blending amount is more than 3 g/g, the rubber composition may deteriorate. may have a sudden impact on the properties of

The base rubber used in the rubber composition of the present invention is natural rubber, synthetic rubber, or a mixed rubber of natural rubber and synthetic rubber, and examples of the synthetic rubber include synthetic imprene rubber, imprene-butanoene random copolymer, etc. can be mentioned,
1 f, 1 f, or 2 or more of these rubbers can be mixed and used in an appropriate ratio.

Among these, it is preferable to use one containing an imprene-butadiene random copolymer.

In this case, the content of the isoprene-butadiene random copolymer in the rubber thread should be 50 parts by weight or more to repel the goal.

The isoprene-butadiene random copolymer has a butanoene moiety of 5 to 70% (weight t%, same hereinafter), especially 10 to 5%.
0chi, and the in-prene part is 30 to 95%, especially 50%.
~90% is preferably used.

Furthermore, iso! The microstructure of the lene-ptanoene random copolymer preferably contains 80% or more of cis-1,4 bonds, more preferably 90% or more, especially 95 or more. It is preferable that there be.

Furthermore, the in-prene-butadiene random copolymer having a Mooney viscosity of 30 to 90, particularly 40 to 70 is preferably used.

The imprene-butadiene random copolymer used in the present invention is prepared by combining imprene and butadiene in the presence of a catalyst, preferably a combination of a lanthanum series rare earth element, an organoaluminum compound, a Lewis base, and optionally a Lewis acid. It can be produced by polymerizing.

In addition to the above-mentioned base rubber and antioxidant, the rubber composition of the present invention may appropriately contain ordinary compounding agents such as a vulcanizing agent, a vulcanization accelerator, a vulcanization aid, and a reinforcing agent. be able to. The blending ratio of these compounding agents is not particularly limited, but usually 0.1 to 2 parts by weight of Xihuang etc. as a vulcanizing agent and 0.1 part by weight of a vulcanization accelerator to 100 parts by weight of the base rubber. ~2 parts by weight, 0.5 to 5 parts by weight of zinc white or the like as a vulcanization aid, and 0 to 20 parts by weight of carbon black or the like as a reinforcing agent.

The rubber composition of the present invention is suitably used as thread rubber, especially thread rubber for thread-wound golf balls. A thread-wound golf goal can be manufactured by doing this. The solid core sphere can be formed using commonly used materials, and the outer skin can be formed using conventional materials such as balata, ionomer resin, etc. Furthermore, the weight, thickness, etc. of the solid core ball, thread rubber layer, and outer skin can be within normal ranges.

Effects of the Invention As described above, the rubber composition according to the present invention is obtained by blending a hindered phenolic antioxidant, a sulfur-based antioxidant, and/or a phosphorus-based antioxidant with natural comb and/or synthetic rubber. When used as thread rubber for golf goals, it has improved strength and elongation at room temperature and high temperatures exceeding 100°C compared to conventional products, and improves workability when winding the thread rubber onto a solid core ball. Aging resistance and high-temperature durability when attached to a cover mold are greatly improved.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Example, comparative example]

Rubber compositions having the compounding ratios shown in Table 1 were prepared, and then vulcanized by a conventional method to prepare each sample.

Next, using each of these samples, the room temperature was 25°C and the daytime temperature was 111°C.
A tensile fracture test was conducted at 00°C, and the strength at break and elongation at break were measured. The results are shown in Table 2.

Furthermore, each sample obtained by the above recipe was coated with a thickness of 0.45+
The rubber thread was processed into a rubber thread with a width of 2 tpaa, and was wound around a rubber core with a diameter of 28 mm using the same procedure as for the production of ordinary thread-wound balls. Evaluation was made as the average number of times the rubber thread broke.

The results are shown in Table 3.

From the results shown in Tables 2 and 3 of Table 3, it is found that the rubber braiding yarn of the present invention does not break and has excellent productivity.

Claims (1)

[Claims] 1. A rubber composition characterized by blending a hindered phenolic antioxidant, a sulfur-based antioxidant, and/or a phosphorus-based antioxidant with natural rubber and/or synthetic rubber.