JPH08187306A - Cover material for composition for golf ball - Google Patents

Abstract

PURPOSE: To provide a soft ball giving a self hitting feel equal to the ball hitting feel of a yarn wound golf ball and to improve the rability and appearance by forming the golf ball of respectively prescribed pts.wt. of an ionomer resin, thermoplastic polyamide elastomer and core shell polymer of prescribed constitution. CONSTITUTION: This cover material compsn. is formed of 90 to 10 pts.wt. metal salt of the ionomer resin, for example, a copolymer of ethylene and methacrylic acid, 10 to 90 pts.wt. thermoplastic polyamide elastomer, for example, a block copolymer of nylon 6 and polyoxytetramethylene glycol and 1 to 30 pts.wt. core shell polymer. The core shell polymer is formed of a rubber-like polymer core having an epoxy group and/or carboxyl group and/or carboxylic acid anhydride and glassy polymer shell. The Shore D hardnesses of the ionomer resin and the thermoplastic polyamide elastomer are respectively set at >=55 and <=50.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cover material composition for a golf ball which has good resilience, a soft shot feeling equivalent to that of a wound golf ball, excellent durability, and good appearance. Regarding things.

[0002]

2. Description of the Related Art Golf balls generally used include a wound golf ball and a two-piece golf ball. A two-piece golf ball is formed by covering a core made of a rubber composition with a cover material such as an ionic ethylene copolymer resin having excellent impact resistance and resilience. Two-piece golf balls are used by many golfers because of their great flight distance and excellent durability. However, because the feel at the time of hitting is hard, many golfers prefer the soft shot feeling of a thread wound golf ball, and in recent years, a two-piece golf ball having a soft shot feeling close to that of a thread wound golf ball. Development is desired.

Conventionally, in order to soften the shot feeling by softening a two-piece golf ball, a soft ionomer resin mixture obtained by mixing an ionomer resin having a high hardness and an ionomer resin having a low hardness is used as a cover material for a golf ball. Proposed (Japanese Patent Laid-Open No. 1-308577,
JP-A-5-3931 and JP-A-5-277208). However, since the ionomer resin also decreases the impact resilience as the hardness decreases, mixing a high hardness ionomer resin and a low hardness ionomer resin with low impact resilience reduces the resilience of the obtained soft ionomer resin mixture. There was a problem.

[0004]

SUMMARY OF THE INVENTION The present invention provides a golf ball cover which has good resilience, a soft shot feeling equivalent to that of a thread-wound golf ball, excellent durability, and a good appearance. An object is to provide a wood composition.

[0005]

The golf ball cover material composition of the present invention comprises an ionomer resin of 90 to 10 parts by weight, a thermoplastic polyamide elastomer of 10 to 90 parts by weight, and a rubbery polymer core and a glassy polymer. It is characterized by comprising 1 to 30 parts by weight of a core / shell polymer composed of a shell.

As described above, by using the composition comprising the ionomer resin, the thermoplastic resin polyamide elastomer and the core / shell polymer as the cover material for the golf ball, the resilience is good and the same as that of the thread wound golf ball. It has a soft shot feeling and excellent durability,
It is possible to obtain a golf ball having a good appearance.

The structure of the present invention will be described in detail below. (1) Ionomer resin An ethylene-unsaturated carboxylic acid copolymer as a base resin, which is obtained from an ethylene-unsaturated carboxylic acid copolymer and a metal compound capable of supplying cations or an organic amine To be

The ethylene-unsaturated carboxylic acid copolymer is
For example, ethylene and an unsaturated carboxylic acid having 3 to 6 carbon atoms,
For example, it is a copolymer with acrylic acid, methacrylic acid, maleic acid, fumaric acid, vinyl benzoate or the like. The metal compound capable of supplying cations is, for example, formate salt such as alkali metal, alkaline earth metal or transition metal, acetate salt,
Examples thereof include nitrates, carbonates, hydrogen carbonates, oxides, hydroxides and alkoxides. As the type of metal, Na, Z
n, Li, Mg, Mn, Ca, Co, K and the like. The organic amine is, for example, an aromatic or alicyclic compound having a bisaminoalkyl group. For example, m-xylenediamine, o-xylenediamine, p-xylenediamine,
Alternatively, hydrogenated products thereof are 1,3-bisaminomethylcyclohexane, 1,2-bisaminomethylcyclohexane, 1,4-bisaminomethylcyclohexane and the like.

This ionomer resin has a Shore D hardness.
The hardness is 55 or more, preferably Shore D hardness of 60-80. The Shore D hardness is 55 or more because the higher the hardness of the ionomer resin, the higher the impact resilience. Further, the Shore D hardness of 60 to 80 is preferable because an ionomer resin having a Shore D hardness of less than 60 has a low impact resilience, while a Shore D hardness of more than 80 causes the thermoplastic polyamide elastomer to be mixed. This is because there is no effect and the shot feeling of the obtained golf ball becomes too hard.

Examples of this ionomer resin include:
Examples thereof include metal salts of copolymers of ethylene and methacrylic acid. This ionomer resin is a known one, and as a commercially available product, for example, Mitsui DuPont Polychemical Co., Ltd.Himilan 1605, Himilan 1706, Himilan 1707, Himilan AM7315, Himilan AM7317,
High-Milan AM7318 etc. (2) Thermoplastic polyamide elastomer Since the thermoplastic polyamide elastomer has a polyamide component in its molecule, the compatibility with the ionomer resin is better than that of other thermoplastic elastomers. Further, the lower the hardness of the thermoplastic polyamide elastomer is, the higher the impact resilience is, and therefore, it is more effective as a component for softening the cover material.

As the thermoplastic polyamide elastomer, nylon 6 and nylon 1 are used as hard segments.
1.A block copolymer having a polyamide component such as 1, nylon 12, and aromatic polyamide, and a polyoxyalkylene glycol such as polyoxytetramethylene glycol or polyoxypropylene glycol or a fatty acid polyester as a soft segment is used. it can.

This thermoplastic polyamide elastomer is
Shore D hardness 50 or less, preferably Shore D hardness 20 to
50's. The Shore D hardness of 20 to 50 is preferable because the thermoplastic polyamide elastomer having a Shore D hardness of less than 20 has a low content of the polyamide component in the hard segment and thus has poor compatibility with the ionomer resin. On the other hand, when the Shore D hardness exceeds 50, the effect of softening the cover material is small and the shot feeling is not improved.

This thermoplastic polyamide elastomer is
Known, commercially available, PEBAX2533 manufactured by Atchem, PEBAX3533, PEBAX4033, Daiamide-PAE E40 manufactured by Daicel-Huls, Daiamide-PAE E47, Grillon manufactured by Ems Japan, Grillamide, There are Grelax A manufactured by Dainippon Ink and Co., Novamid EL manufactured by Mitsubishi Kasei, and UBE-PAE manufactured by Ube Industries. (3) Core / Shell Polymer It is composed of a rubber-like polymer core and a glass-like polymer shell. Preferably, the core has an epoxy group and / or a carboxyl group and / or a carboxylic acid anhydride group on the surface, and the shell does not contain an epoxy group, a carboxyl group or a carboxylic acid anhydride group, and a functional group reactive therewith. Composed of things.

Core of rubber-like polymer, for example, conjugated diene or alkyl group having 2 to 8 carbon atoms
An alkyl acrylate or a mixture thereof, which is
The epoxy group and / or carboxyl group and / or carboxylic acid anhydride group-containing monomer is polymerized to form a rubbery polymer having a glass transition temperature of −20 ° C. or lower. When the glass transition temperature is higher than -20 ° C, the effect of improving low temperature durability becomes insufficient.

Examples of such conjugated dienes include butadiene, isoprene and chloroprene, and butadiene is particularly preferable. The number of carbon atoms in the alkyl group is 2
Examples of the alkyl acrylate having 8 to 8 include ethyl acrylate, propyl acrylate, butyl acrylate, cyclohexyl acrylate, and 2-ethylhexyl acrylate, and butyl acrylate is particularly preferable.

Examples of the epoxy group-containing monomer include glycidyl acrylate, glycidyl methacrylate,
4,5-epoxybenzyl acrylate, 4,5-epoxybenzyl methacrylate, allyl glycidyl ether,
There are butadiene monoepoxide and the like, and glycidyl acrylate and glycidyl methacrylate are particularly preferable. As a carboxyl group-containing monomer, even if it has many carbon atoms
Examples of the α, β-unsaturated carboxylic acid having 30 or less, preferably 25 or less, such as acrylic acid, methacrylic acid and α
-Hydroxymethyl acrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid and the like are mentioned, and methacrylic acid and itaconic acid are preferable.

Examples of the carboxylic acid anhydride group-containing monomer include α, β-unsaturated dicarboxylic acid anhydrides having at most 30, preferably 25 or less carbon atoms, preferably maleic anhydride and fumaric anhydride. Acid, itaconic anhydride,
Examples include citraconic anhydride and the like. Crosslinking monomers such as butylene glycol diacrylate, hexanediol diacrylate, etc. to obtain higher low temperature durability,
Grafting monomers such as allyl methacrylate and allyl acrylate are used.

A glass epoxy polymer having a glass transition temperature of 40 ° C. or higher is formed by polymerizing a shell epoxy group, a carboxyl group and a carboxylic acid anhydride group of the glassy polymer , and a monomer having no functional group reactive therewith. When the glass transition temperature is 40 ° C or lower,
It is not practically preferable because it aggregates during handling because of stickiness.

The functional group reactive with the epoxy group, the carboxyl group or the carboxylic acid anhydride group means an amino group, an imino group, a carboxyl group, a carboxylate group,
Examples thereof include a hydroxyl group, an isocyanate group, a sulfonic acid group, and a sulfonate group. Examples of the monomer containing no functional group reactive with an epoxy group include alkyl acrylates such as ethyl acrylate and butyl acrylate, alkyl methacrylates such as methyl methacrylate and butyl methacrylate, and aromatics such as styrene, vinyltoluene and α-methylstyrene. Examples thereof include vinyl cyanide such as group vinyl, aromatic vinylidene, acrylonitrile and methacrylonitrile, and vinyl polymerizable monomers such as vinylidene cyanide, but particularly methyl methacrylate, styrene and acrylonitrile are used.

The shell is preferably in the range of 5 to 50% by weight based on the whole core-shell polymer. (4) Golf ball cover material composition of the present invention: 90 to 10 parts by weight of the above-mentioned ionomer resin, 10 to 90 parts by weight of thermoplastic polyamide elastomer, and 1 to 30 parts by weight of core / shell polymer. The reason why the ionomer resin is 10 to 90 parts by weight is that the cover material is too soft and the resilience is poor when it is less than 10 parts by weight, and when it exceeds 90 parts by weight, the hit feeling is different from the wound golf ball because the cover material is hard. Because it will be a good thing. It is preferably 20 to 80 parts by weight.

Further, thermoplastic polyamide elastomer 90
Contrary to the compounding amount of the ionomer resin, the content of up to 10 parts by weight is because the cover material is too soft and the resilience is poor when it exceeds 90 parts by weight, and the mixing effect of the thermoplastic polyamide elastomer is less than 10 parts by weight. Does not appear, and because the cover material is hard, the shot feeling is different from that of the thread-wound golf ball. It is preferably 80 to 20 parts by weight.

The amount of the core / shell polymer compounded is 1 to 30.
Parts by weight. This is because if it is less than 1 part by weight, the durability and appearance (fluffy state after the polishing step) cannot be improved, and if it exceeds 30 parts by weight, the resilience is lowered. Preferably, it is 2 to 25 parts by weight. For mixing, a roll, a Banbury mixer, an extruder for plastics, especially a twin-screw extruder is preferable, and the temperature of the cylinder and the die head may be 150 to 250 ° C. If necessary, additives such as antioxidants, stabilizers, lubricants, colorants and the like may be appropriately added. In addition, an elastomer other than the thermoplastic polyamide elastomer, an ethylene-α-olefin copolymer, or the like may be added as appropriate. Elastomers other than thermoplastic polyamide elastomers include polyester elastomers, polyurethane elastomers, polyolefin elastomers,
There are polystyrene elastomers and vinyl chloride elastomers. As an ethylene-α olefin copolymer, AF made by Dow Chemical Co., which is a copolymer of ethylene and octene.
There are FINITY POP and ENGAGE POE.

[0023]

[Examples] Melt-kneading was performed at a temperature of 200 ° C using a twin-screw extruder according to the compounding recipe (indicated by weight) shown in the upper part of Tables 1 and 2. The resulting composition was injection-molded onto a solid core having a diameter of 38.3 mm and a compression value of 40 kgf at the time of deformation of 2.54 mm (compound formulation shown in Table 3 in parts by weight) to a thickness of 2.2 mm, I got a golf ball. The characteristics of each ball are shown in Tables 1 and 2.

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

[Table 3]

Note) * 1 Himilan 1605 (Sodium ionic ethylene-methacrylic acid copolymer manufactured by DuPont Mitsui Polychemical, Shore D hardness 67). * 2 Himilan AM7316 (Sodium ionic ethylene-methacrylic acid-methacrylic acid ester-based copolymer, Shore D hardness 24, manufactured by Mitsui DuPont Polychemical Co., Ltd.). * 3 PEBAX 2533 (ATOCHEM thermoplastic polyamide elastomer, Shore D hardness 25). * 4 PEBAX 3533 (ATOCHEM thermoplastic polyamide elastomer, Shore D hardness 35). * 5 PEBAX 4033 (ATOCHEM thermoplastic polyamide elastomer, Shore D hardness 40). * 6 PEBAX 6333 (ATOCHEM thermoplastic polyamide elastomer, Shore D hardness 63). * 7 Staphyroid IM-203 (Takeda Yakuhin Kogyo core /
Shell type impact modifier, particle system 0.3μ, having epoxy group on core surface). * 8 Measured at 23 ° C using a Shore D hardness tester (ASTM
D2240). * 9 The relative number of hits until Comparative Example 1 was 100 when the driver (Wood club # 1) was hit with a head speed of 43 m / sec using a swing robot, and the number of hits was 100. * 10 The relative speed when the golf ball is hit with a driver (Wood club # 1) at a head speed of 43 m / sec using a swing robot, and the initial speed ratio of the golf ball to the head speed is 100 when Comparative Example 1 is set. * 11 Visual inspection of the ball surface after painting. * 12 Driver by a professional golfer (Wood club
The feeling of hitting with # 1). * 13 BR01 (Polybutadiene rubber manufactured by Japan Synthetic Rubber Co., Ltd., cis 1,4 structure 97%). * 14 UA-101H (manufactured by Kyoeisha Oil and Fat Co., Ltd., reaction product of hexamethylene diisocyanate and glycerin dimethacrylate, functional group number about 4) * 15 AEROSIL 200 (manufactured by Nippon Aerosil). * 16 Dicumyl peroxide. * 17 The force (kgf) required to deform a golf ball 1/10 inch (2.54mm) at a compression speed of 10mm / min. As is clear from Table 1 and Table 2, Examples 1 to 12 have the same cover material hardness as Comparative Examples 1 to 3, but have good resilience and soft shot feeling. further,
In Comparative Examples 1 to 3, the soft ionomer resin (A-2)
When the addition amount of is increased, the resilience is extremely lowered together with the decrease in hardness, but in Examples 1 to 3, 4 to 6 and 7 to 9, the resilience is less deteriorated. In these examples, the addition amount is different depending on the type of polyamide elastomer, the higher the hardness of the polyamide elastomer,
This is because the amount required to soften the cover material increases. Examples 10 to 12 are formulation examples in which the added amount of the core / shell polymer is changed, and it can be seen that even if 2 parts by weight of the core / shell polymer is added, the durability and the appearance are improved. When the amount of the core / shell polymer is increased, the resilience is slightly decreased, but the durability is significantly improved. In Comparative Example 4, the resilience is good, but since the core / shell polymer is not added, the surface of the cover material becomes fluffy in the polishing step and the durability is poor. In Comparative Example 5, since the polyamide elastomer (B-4) having a Shore D hardness of more than 50 was used, the cover material was not softened and the shot feeling was hard, and no improvement effect was observed.

[0028]

As described above, according to the present invention, since the ionomer resin, the thermoplastic polyamide elastomer and the core / shell polymer are blended, the resilience is good and the hit feeling is similar to that of the thread wound golf ball. It is possible to provide a golf ball cover material composition having the following characteristics, excellent durability, and good appearance.

Claims (4)

[Claims] 1. A golf ball comprising 90 to 10 parts by weight of an ionomer resin, 10 to 90 parts by weight of a thermoplastic polyamide elastomer, and 1 to 30 parts by weight of a core / shell polymer composed of a rubbery polymer core and a glassy polymer shell. Cover material composition. 2. The ionomer resin is Shore D hardness
The golf ball cover material composition according to claim 1, which is 55 or more. 3. The golf ball cover material composition according to claim 1, wherein the thermoplastic polyamide elastomer has a Shore D hardness of 50 or less. 4. The golf ball cover material according to claim 1, 2 or 3, wherein the core of the rubber-like polymer is a core having an epoxy group and / or a carboxyl group and / or a carboxylic acid anhydride group on the surface. Composition.