JPS6176177A - Yarn wound golf ball - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thread-wound golf ball in which a cover layer is formed on a thread rubber layer formed around a core ball. As a rubber, it has low hysteresis loss during high stretching, and has high tensile strength at high temperatures.
This invention relates to a thread-wound golf ball that has improved flight characteristics by using a thread rubber that is resistant to elongation and has good workability during manufacturing.

I'm confused! Conventionally, the thread rubber layer of thread-wound golf balls has been formed of thread rubber whose main components are natural rubber <NR> and synthetic isoprene rubber (IR).

This is because thread rubber whose main component is natural rubber has a large hysteresis loss during high stretching, and therefore it is difficult to obtain a thread rubber layer with high elasticity when using this. A highly elastic thread rubber layer is obtained by using a thread rubber blended with synthetic isoprene rubber that has low loss. In this case, the greater the blending amount of synthetic isoprene rubber with respect to natural rubber, the smaller the hysteresis loss during high stretching of the rubber thread.Therefore, the higher the content of synthetic isoprene rubber, the higher the elasticity and the better the flight characteristics. It is believed that a golf ball can be obtained.

Problems to be Solved by the Invention However, in the past, there was a limit to increasing the amount of synthetic isoprene rubber blended with respect to natural rubber in order to improve flight characteristics. That is, when the blending amount of synthetic isoprene rubber with respect to natural rubber is increased, the properties of the thread rubber, especially the tensile strength and elongation at high temperatures, decrease considerably, and therefore, the thread with too high a content of synthetic isoprene rubber Rubber cannot be used as a material for the thread rubber layer because it is subjected to high heat history during coating with the cover layer. Furthermore, rubber materials containing a large amount of synthetic isoprene rubber have the problem that it is difficult to obtain a uniform rubber sheet, and furthermore, the processability when forming thread rubber is poor.

Therefore, even if the ratio of synthetic isoprene rubber to natural rubber is higher than before, the hysteresis loss is small, the tensile strength at high temperatures, the collapse due to elongation, and the processability when manufacturing thread rubber is good, making it a highly elastic thread rubber. A rubber material suitable for coloring the layer has been desired, and as a result of various research into obtaining such a rubber material, the inventors have developed a rubber material whose main components are natural rubber and synthetic isoprene rubber. In contrast, blending a reinforced rubber composition in which short fibers of a thermoplastic polymer having -6-NH- groups in the molecule are grafted to a vulcanizable rubber via an initial condensate of a phenol formaldehyde resin. As a result, even when the synthetic isoprene rubber content is increased, a rubber material with high tensile strength and elongation at high temperatures and good processability can be obtained. The present inventors have discovered that a thread-wound golf ball can be obtained in which the layers can be formed well and the flight characteristics are excellent, and the present invention has been completed.

That is, the smaller the hysteresis loss of the thread rubber, the greater the flying distance of a thread-wound golf ball, so it is preferable for the thread rubber to contain a large amount of synthetic isoprene rubber, which has a smaller hysteresis loss during high stretching than natural rubber. However, by mixing synthetic isoprene rubber, processability deteriorates, and the physical properties of the rubber, particularly tensile strength and elongation at high temperatures, deteriorate significantly. In the present invention, short fibers of the thermoplastic polymer are blended into the rubber component to make the rubber S+
By increasing the fi strength, the processability and physical properties of the rubber, as well as the tensile strength and elongation at high temperatures, are significantly improved, making it possible to increase the content of synthetic isoprene rubber.

The present invention will be explained in more detail below.

1111 E The golf ball according to the present invention is a thread-wound golf ball in which a thread rubber layer formed around a core ball layer is covered with a cover layer, and the thread rubber forming the thread rubber layer is made of natural rubber and synthetic isoprene. A reinforced rubber composition comprising a rubber and a vulcanizable rubber in which short fibers of a thermoplastic polymer having 10-NH- groups in the molecule are grafted via an initial condensate of a phenol formaldehyde resin. It uses things.

In this case, it is preferable to use a synthetic isoprene rubber having at least 30%, especially 80% or more of cis-1,4 bonds in order to improve the flight characteristics of the ball.

The reinforcing rubber composition may include, for example, a vulcanizable rubber, a thermoplastic polymer having 100 NH- groups in the polymer molecule with a molecular ff of less than 1200000, and a total of 1100 fflf of these rubbers and the thermoplastic polymer.
An initial 1ilI condensate of phenol-formaldehyde resin in an amount of 0.2 to 5 parts per fi part and a compound capable of generating formaldehyde when heated are kneaded at a temperature above the melting point of the thermoplastic polymer and below 270°C, and 1q If the ratio of rubber and thermoplastic polymer in the kneaded product is 1 to 100 parts of thermoplastic polymer per 10011 parts of rubber, the ratio of rubber and thermoplastic polymer in the kneaded product remains unchanged. When the amount of thermoplastic polymer is greater than 1001 parts per 100 fflf L611 of rubber, additional vulcanizable rubber is added to the mixer at a rate of 1 to 100 mff 1 part thermoplastic polymer per ioomi parts of total rubber, and further heated. Above the melting point of the plastic polymer and 270
It is preferable to use a product produced by kneading at a temperature of ℃ or below, extruding at a temperature above the melting point of the thermoplastic polymer and below 270 ℃, and stretching the extrudate at a temperature below the melting point of the thermoplastic polymer. Can be done.

In this case, as the vulcanizable rubber, all rubbers that give a rubber elastic body by vulcanization can be used, such as natural rubber, cis-1,4-polybutadiene, polyisoprene, polychloroprene, Examples include styrene-butadiene copolymer rubber, isobrene-butylene copolymer, ethylene-propylene-nonconjugated diene terpolymer, and mixtures thereof. Among these rubbers, a mixture of a vulcanizable rubber, a thermoplastic poly7- containing -CONl-1- group in the molecule, a first 11Qli1 compound of phenol-formaldehyde resin, and a compound that can generate formaldehyde when heated is used. Natural rubber is preferred because it is hardly mixed and gelled when the kneaded product is extruded.

Further, the fine short fibers of the thermoplastic polymer may be nylon 6, nylon 6101, nylon 12, nylon 611, nylon 12, etc. having a melting point of 190 to 235°C, preferably 190 to 225°C, particularly preferably 200 to 220'C. It is preferably formed from a thermoplastic polymer having 100NH-W in the polymer molecule, such as nylon such as 612, polyurea such as polyhebutamethylene urea, polyundecamethylene urea, or polyurethane, and preferably nylon. , has an average diameter of 0.05 to 0.8 μ, has a circular cross section, has a shortest a! fiber length of preferably 1 μ or more, and is processed in the form of fine short fibers with molecules arranged in the fiber axis direction. Preferably, it is embedded in sulfurable rubber.

The phenol formaldehyde resin has the following general formula (where R is an alkyl group or a combination of a hydrogen atom and an alkyl group, X is a hydroxyl group or a halogen atom such as chlorine or bromine, and m is 1 or 2,
n is an integer from 2 to 15. Examples include resol-type alkylphenol-formaldehyde resins represented by (), such as resol-type initial condensates obtained by reacting an alkylphenol such as cresol with formaldehyde or acetaldehyde in the presence of an alkali catalyst, and modified products thereof. In this case, as the resol type alkylphenol formaldehyde resin, those having two or more methylol groups in the molecule can be particularly preferably used.

Furthermore, as a phenol formaldehyde resin, for example, phenols such as phenol and bisphenols and formaldehyde (paraformaldehyde may also be used) using an acid such as sulfuric acid, hydrochloric acid, phosphoric acid, or oxalic acid as a catalyst.
Novolac-type phenol-formaldehyde-based a1 fats such as soluble resins obtained by condensation reaction with and modified products thereof are included. In this case, as the novolak-type phenol-formaldehyde resin, for example, a novolak-type phenol-formaldehyde initial condensate, a novolak-type lactam-bisphenol F-formaldehyde initial condensate, a novolak-type styrenated phenol-phenol-formaldehyde initial condensate, etc. are preferably used. can.

The above-mentioned reinforced rubber composition contains 1 to 100 fine short fibers of a thermoplastic polymer having 100 N H- groups in the polymer molecule in 100 parts of the vulcanizable rubber, preferably 1 It is preferred that up to 70 parts by weight, particularly preferably 30 to 70 parts by weight, be embedded.

In addition, in the above-mentioned reinforced rubber composition, at the interface of the tli strip with the amount of fine short fibers of the thermoplastic polymer embedded in the vulcanizable rubber, thermoplastic The grafting ratio, expressed as the weight ratio of vulcanizable rubber grafted to the polymer (vulcanizable rubber/fine short fibers of thermoplastic polymer), is 3 to 25 weight percent, especially 5 to 20 weight percent. It is preferable that the thermoplastic polymer forming the fiber and the vulcanizable rubber are graft-bonded via an initial condensate of phenol formaldehyde resin so that the fibers are formed in a small amount.

In the rubber thread used in the present invention, the compounding ratio of natural rubber and synthetic isoprene rubber (11 ratio) is 50:
It is preferable to set it as 50-10:90. In this case, the thread rubber of the present invention has high tensile strength and elongation at high temperatures, and has good processability during the production of thread rubber, even if the hysteresis loss during high stretching is reduced by increasing the m content of synthetic isoprene rubber. It is something.

Further, the reinforced rubber composition is preferably blended such that short fibers of the thermoplastic polymer are contained in an amount of 1 to 15 parts by weight, preferably 2 to 5 parts by weight, based on 100 parts by weight of the total rubber component. In this case, the thermoplastic polymer short! L fiber is 15m
When the amount exceeds m parts, the increase in hysteresis loss due to the addition of this becomes significant, and synthetic isoprene rubber l! The effect of ld coupling is canceled out, and the high-temperature characteristics are #f! Even if J, L/ is added, the effectiveness of its addition may be lost.

The rubber thread used in the present invention contains a vulcanizing agent and other usual additives such as antioxidants, reinforcing agents, plasticizers, etc. in addition to the above components.
It is prepared by a conventional method by appropriately blending a laxative and other compounded chemicals. In this case, other rubber components may be blended, for example, polybutadiene rubber or the like may be blended in an amount of 101% or less of the total rubber components.

The thread-wound golf ball of the present invention can be manufactured by winding the above-mentioned thread rubber around a core ball and covering the thread rubber layer with an outer skin, but in this case, the core ball is formed using a commonly used material. The outer skin can also be formed using conventional materials such as balata, ionomer resin, etc.

Note that the shape, thickness, etc. of the core ball, thread rubber layer, and outer skin can be within normal ranges.

11 Tragedy 1 As explained above, the golf ball according to the present invention is a thread-wound golf ball in which a thread rubber layer formed around a core ball layer is covered with a cover layer. A reinforced rubber composition in which short fibers of a thermoplastic polymer having -CONH- groups in the molecule are grafted to natural rubber, synthetic isoprene rubber, and vulcanizable rubber via an initial synthesis product of a phenol formaldehyde resin. By using a rubber thread containing , the hysteresis loss of the thread rubber is small and the thread has smooth flight characteristics, the tensile strength and elongation at high temperatures of the thread rubber are large, and the processability during manufacturing of the thread rubber is good. It is advantageous in manufacturing.

Next, a production example of the reinforced rubber composition used in the present invention will be shown.

[Manufacturing Example 1 Set at 150°C and 1100pp] Natural rubber 140011J with a Mooney viscosity of 25 at 100'C and σN-(3-methacryloyl oyase 2-hydroxypropyl)- were placed in an OOC Banbury mixer (manufactured by Kobe Steel). N-Phenyl-p-phenylenediamine (Product name: Nocrat)
After adding 14g of 6-Nylon (trade name: 10
30B, manufactured by Ube Industries, Ltd., melting point: 221°C, 1 molecule of hydrogen: 30
000) was added, and the strands were stranded for 7 minutes. During this time, the humidity inside the mixer rose to 232°C, and the 6-nylon melted.

Next, novolac type phenol formaldehyde initial condensate (trade name: 550PL Showa Kasei Co., Ltd.'M>30
! After adding II and kneading with water for 7 minutes, hexamethylenetetramine 39 was added and kneaded for 2.5 minutes (the temperature of the mixer batter during mixing was 230° C.) to cause a graft reaction and then dumping. The obtained rope kneading material was stringed at a set temperature of 235°C using a 30 mm (diameter) extruder (manufactured by Ikegai Co., Ltd.) having a circular diamond with a nozzle inner diameter of 2 mm and a length-to-inner diameter ratio (L/D) of 2. extruded into a shape, and the extrudate was heated to O℃
It was cooled and solidified with cooling water, and then wound up on a bobbin through a guide roll at a draft ratio of 9 and a speed of 35 m/min. After vacuum-drying this roll for a day and night at room temperature to remove adhering water, 500 rolls of this roll were bundled into a sheet (thickness: 2 x 1 width: 150 rolls), and this sheet-like material was separated by roll spacing. Approximately 1C with a pair of rolling rolls at 0.2 pulse and a temperature of 60'C
) f8 roll rolling to obtain a reinforced rubber composition.

Note that this manufacturing method is based on the method described in Japanese Patent Application Laid-Open No. 59-43041.

Next, examples and comparative examples will be shown to specifically explain the present invention.

[Example, Comparative Example 1 Rubber threads Nos. 1 to 4 having the compositions shown in Table 1 were manufactured by a conventional method. The synthetic isoprene rubber used was ariflex 309 manufactured by Shell Chemical Co., Ltd.

Next, the tensile strength and elongation of these rubber threads as v1 products and at 70°C were measured and compared. The results are shown in Table 1. In Table 1, the retention rate is the ratio (%) of the tensile strength or elongation at 70° C. to the tensile strength or elongation at Va.

From the results in Table 1, it was confirmed that the rubber threads of No. 2 to 4 (Examples) used in the present invention were extremely excellent in tensile strength and elongation at high temperatures. On the other hand, the thread rubber of N001 (comparative example) which did not contain nylon staple fibers was significantly inferior in tensile strength and elongation at high temperatures.

Claims (1)

[Claims] 1. A thread-wound golf ball in which a thread rubber layer formed around a core ball is covered with a cover layer, wherein the thread rubber forming the thread rubber layer is natural rubber, synthetic isoprene rubber, Vulcanizable rubber has ▲mathematical formulas, chemical formulas, tables, etc. in its molecules.▼Reinforced rubber compositions in which short fibers of thermoplastic polymers having groups are grafted via an initial condensate of phenol formaldehyde resin. A thread-wound golf ball characterized by containing: 2. The thread-wound golf ball according to claim 1, wherein the blending ratio of natural rubber and synthetic isoprene rubber in the thread rubber is from 50:50 to 10:90 by weight. 3.The amount of short fibers of thermoplastic polymer is 1 for the total rubber component.
The thread-wound golf ball according to claim 1 or 2, wherein the amount is 1 to 15 parts by weight per 00 parts by weight.