JPH09192264A - Golf ball resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a golf-ball resin composition that is soft and excellent in resiliency and durability. SOLUTION: This resin composition that is formed into the cover member of a golf ball is formed using at least one kind of molten mixture, selected from a group consisting of ionomer resins, ethylene-octene copolymers, polyolefins modified by unsaturated carboxylic acid or its anhydride, modified olefin copolymers, and olefin copolymers having unsaturated carboxylic acid anhydride or glycidil ester as a copolymerized component.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition for golf balls which is flexible and has excellent resilience and durability.

[0002]

2. Description of the Related Art Conventionally, ionomer resins have been widely used as golf ball cover materials because they have the advantages of excellent resilience and durability. However, the golf ball using the ionomer resin as the cover material has the drawbacks that not only the hit feeling is hard but also the controllability is poor. Therefore, there is a demand for a golf ball having improved hitting feel and controllability without impairing the above-mentioned advantages of the ionomer resin.

So far, for example, a conventional ionomer resin is mixed with a soft ionomer resin which is a sodium salt or a zinc salt of an ethylene / (meth) acrylic acid / (meth) acrylic acid ester terpolymer. Method (JP-A-1-308577, JP-A-5-3931) or a method of mixing an ionomer resin and a partially saponified ethylene / unsaturated carboxylic acid ester copolymer (JP-A-5-345051). JP-A-6-3130
No. 75), the cover has been made soft to improve the feel and control of impact.

[0004]

However, when a cover material mixed with a soft ionomer resin is used, there is a problem that the resilience is lowered due to the softening of the cover. Further, since the compatibility between the conventional ionomer resin and the soft ionomer resin is not good, there is a problem that durability is lowered and fluff is generated on the cover surface of the golf ball, resulting in poor appearance.

Also, when a cover material in which a partially saponified ethylene / unsaturated carboxylic acid ester copolymer is mixed is used, the ionomer resin and the partially saponified ethylene / unsaturated carboxylic acid ester copolymer are mixed with each other. Since the compatibility is not good, there is a problem that the durability is deteriorated and the appearance is deteriorated.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a resin composition for golf balls which is flexible and has excellent resilience and durability.

[0007]

In order to solve the above problems, the present invention provides an ionomer resin, an ethylene / octene copolymer, a modified polyolefin with an unsaturated carboxylic acid or an anhydride thereof, and a modified olefin copolymer. Polymer,
It is a melt mixture of at least one selected from the group consisting of olefinic copolymers containing an unsaturated carboxylic acid anhydride or glycidyl ester as a copolymerization component.

In the present invention, the ionomer resin is generally a resin obtained by neutralizing a part of the carboxyl groups of an ethylene / unsaturated carboxylic acid copolymer with a metal ion or a mixture thereof. As the unsaturated carboxylic acid in the acid copolymer, acrylic acid,
Methacrylic acid is preferred.

Examples of the metal ion for neutralizing a part of the carboxyl groups of the ethylene / unsaturated carboxylic acid copolymer include alkali metal ions such as lithium, sodium and potassium, divalent metal ions such as zinc, magnesium and calcium. However, it is preferable to use a combination of two or more kinds of metal ions capable of obtaining a synergistic effect of increasing the resilience. At least one alkali metal ion,
Examples include combinations of at least one divalent metal ion such as lithium / zinc, sodium / zinc, potassium / magnesium, and lithium / sodium / zinc. Generally, two or more ionomer resins having different metal ions are used. It is possible to mix and obtain a combination of two or more metal ions.

As the ionomer resin, "SURLYN" (trade name) manufactured by DuPont, USA and "HIMIRAN (HI) manufactured by DuPont Mitsui Polychemicals Co., Ltd.
"MILAN)" (trade name) and "Iotek" (trade name) manufactured by Exxon Co. are commercially available. In addition, "Surlyn" and "High Milan" are ethylene
It is an ionomer resin of methacrylic acid copolymer system,
"Iotech" is an ionomer resin of ethylene-acrylic acid copolymer system.

Such an ionomer resin has a Shore D hardness of 60 or more in order not to reduce the resilience, and 190 ° C., 2160 in order not to reduce the moldability.
It is preferable that the MFR under g load is 0.7 dg / min or more.

The ethylene / octene copolymer is a copolymer of ethylene and octene which is an α-olefin having 8 carbon atoms, and the ethylene / octene copolymer used in the present invention has a molecular weight distribution of less than 3. It is preferable that the main chain has a long chain branch, and “Affinity (AFFINITY)” (trade name) and “ENGAGE” (trade name) manufactured by Dow Chemical Company are commercially available. The "affinity" has a density of 0.880-
The content of octene is 2 to 20 at 0.935 g / cm ^3.
% By weight, and "engage" has a density of 0.863 ~
The content of octene is 0.880 g / cm ³ and is 20% by weight or more.

The ethylene / octene copolymer is shore D because it has flexibility without lowering the resilience.
It is preferable that the hardness is less than 60 and the MFR at 190 ° C. under a load of 2160 g is 0.5 dg / min or more.

At least one selected from the group consisting of a modified polyolefin with an unsaturated carboxylic acid or an anhydride thereof, a modified olefin copolymer, an olefin copolymer containing an unsaturated carboxylic acid anhydride or a glycidyl ester as a copolymerization component. Regarding one type, modified polyolefins with unsaturated carboxylic acids or their anhydrides, modified olefinic copolymers include polyethylene modified with acrylic acid, methacrylic acid, crotonic acid, fumaric acid, maleic anhydride, itaconic anhydride, etc. , Polypropylene, ethylene / propylene copolymer, ethylene / vinyl acetate copolymer and the like.

As the olefinic copolymer containing unsaturated carboxylic acid anhydride or glycidyl ester as a copolymerization component, ethylene / glycidyl (meth) acrylate copolymer, ethylene / vinyl acetate / glycidyl (meth) acrylate Ethylene / (meth) acrylic acid ester / maleic anhydride terpolymer containing ethylene, (meth) acrylic acid methyl, ethyl, n-butyl, isobutyl ester, etc. )
Examples thereof include acrylic acid ester / glycidyl (meth) acrylate terpolymers.

These are ionomer resin and ethylene.
It is for improving the compatibility with the octene copolymer, not lowering the durability, and not causing a poor appearance.

In the present invention, the mixing ratio of the ionomer resin and the ethylene / octene copolymer is 40 to 95 parts by weight of the ionomer resin and 5 to 60 parts by weight of the ethylene / octene copolymer, with the total amount of both components being 100 parts by weight. Is preferred. If the mixing ratio of the ionomer resin is small and the mixing ratio of the ethylene / octene copolymer is large, the resilience and durability are lowered. On the other hand, if the mixing ratio of the ionomer resin is high and the mixing ratio of the ethylene / octene copolymer is low, flexibility cannot be obtained.

Further, it is selected from the group consisting of a modified polyolefin with an unsaturated carboxylic acid or an anhydride thereof, a modified olefin copolymer, an olefin copolymer containing an unsaturated carboxylic acid anhydride or a glycidyl ester as a copolymerization component. The mixing ratio of at least one kind is preferably in the range of 1 to 25 parts by weight with respect to 100 parts by weight of the total amount of the ionomer resin and the ethylene / octene copolymer. If this mixing ratio is low, the effect of improving compatibility cannot be obtained,
If the mixing ratio is high, the resilience is reduced.

The resin composition for golf balls of the present invention is generally produced by melting and mixing the three components using a Banbury mixer for thermoplastic resin, an extruder, etc., but the effects of the present invention are impaired. Other polymers can be mixed in addition to the three components as long as there is no range, and if necessary, colorants, optical brighteners, antioxidants, ultraviolet absorbers, ultraviolet stabilizers, dispersants, etc. Additives can also be mixed. It should be noted that the molten mixture means that it is produced by melt mixing, and does not mean that it is a molten mixture.

The golf ball resin composition of the present invention can be used as a material for a golf ball cover, an intermediate layer of three or more solid golf balls, and the like.

[0021]

Example A rubber composition having the composition shown in Table 1 was heated and pressed in a core mold to prepare a solid core having a diameter of 38.3 mm.

[0022]

[Table 1]

Next, the solid core was coated with a resin composition having the composition shown in Table 2 by an injection molding method, and after cover molding, polishing and coating were performed to obtain a two-piece solid golf ball having a diameter of 42.7 mm. It was Table 2 shows the results of measuring and evaluating the characteristics of the obtained golf balls.

[0024]

[Table 2]

However, in Table 2, * 1: trade name, sodium ion neutralization type ionomer resin manufactured by Mitsui DuPont Polychemical Co., Ltd., Shore D hardness 65, MFR 2.8 dg / min.

* 2: Trade name, zinc ion neutralized ionomer resin manufactured by Mitsui DuPont Polychemical Co., Ltd., Shore D hardness 64, MFR 0.7 dg / min.

* 3: Trade name, ethylene / octene copolymer manufactured by Dow Chemical Co., density 0.870, octene content 24% by weight, Shore D hardness 33, MFR 5.0 dg /
min.

* 4: Trade name, ethylene / n-butyl acrylate / glycidyl methacrylate terpolymer manufactured by Mitsui DuPont Polychemical Co., Ltd.

* 5: A polymer obtained by graft-polymerizing methyl methacrylate onto an ethylene / ethyl acrylate / maleic anhydride terpolymer manufactured by NOF CORPORATION.

* 6: Trade name, maleic anhydride-modified polyethylene manufactured by Sanyo Chemical Industry Co., Ltd.

* 7: Using a swing robot device,
The initial velocity of the golf ball when hit by the No. 1 wood club (# 1), which is an index with Comparative Example 1 being 100.

* 8: An index with the durability of the golf ball of Comparative Example 1 as 100.

* 9: A cover surface after surface grinding was visually evaluated at the time of manufacturing a golf ball, and represents "⊚: extremely good, ◯: good, x: bad".

In this case, as compared with Comparative Example 1 in which only the ionomer resin was used, ethylene was used as the ionomer resin.
Octene copolymer (Engage 8200), modified polyolefin with an unsaturated carboxylic acid or an anhydride thereof (Umex 2000), an olefin copolymer having an unsaturated carboxylic acid anhydride or a glycidyl ester as a copolymerization component (Elvalloy EP, (Modiper A8200)
In each of Examples 1 to 9 containing at least one selected from the group consisting of, the cover hardness is low and the feel on impact is improved while maintaining the resilience and durability. Further, in Comparative Example 2 using the ionomer resin and the ethylene / octene copolymer, the durability and appearance of the manufactured golf ball are poor, whereas in Examples 1 to 9,
In each case, good results have been obtained.

[0035]

According to the present invention, it is possible to provide a resin composition for golf balls which is flexible and has excellent resilience and durability. Further, when used as a cover material for a golf ball, it is possible to provide a golf ball resin composition which does not cause a fluffy appearance defect on the cover surface.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Taro Izawa 5412 Shido, Shido-cho, Okawa-gun, Kagawa Prefecture Inside Casco Co., Ltd.

Claims (5)

[Claims] 1. An ionomer resin, an ethylene / octene copolymer, a modified polyolefin with an unsaturated carboxylic acid or an anhydride thereof, a modified olefin copolymer, an unsaturated carboxylic acid anhydride or a glycidyl ester as a copolymerization component. A resin composition for a golf ball, which is a molten mixture of at least one selected from the group consisting of olefin-based copolymers described below. 2. The resin composition for a golf ball according to claim 1, wherein the ionomer resin has a Shore D hardness of 60 or more. 3. The resin composition according to claim 1, wherein the ethylene / octene copolymer has a Shore D hardness of 6;
A resin composition for a golf ball, which is less than 0. 4. The resin composition according to claim 1, wherein a mixing ratio of the ionomer resin and the ethylene / octene copolymer is 40 to 95 parts by weight of the ionomer resin and 100 parts by weight of the ethylene monomer. A golf ball resin composition, characterized in that the octene copolymer is 5 to 60 parts by weight. 5. The resin composition according to claim 1, wherein the modified polyolefin, the modified olefin-based copolymer, the unsaturated carboxylic acid anhydride or the glycidyl ester with an unsaturated carboxylic acid or an anhydride thereof is used as a copolymerization component. The mixing ratio of at least one selected from the group consisting of the olefin copolymers is 1 to 25 parts by weight based on 100 parts by weight of the ionomer resin and the ethylene-octene copolymer in total. A characteristic resin composition for golf balls.