JPH11197271A - Golf ball - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a golf ball providing a good ball striking feel and good controllability and being excellent in resiliency and flying performance. SOLUTION: In a golf ball having at least a core 1 and a cover 2, the cover 2 is made of a composition in which a mixture of a resin (A) [an ionomer resin (I) obtained when at least a part of a carboxyl group in a ternary copolymer of ethylene, α,β-unsaturated carboxylic acid. and α,β-unsaturated carboxylic acid ester is neutralized by metal ions or a mixture of the ionomer resin (I) and an ionomer resin (II) obtained when at least a part of a carboxyl group in a copolymer of ethylene and α,β-unsaturated carboxylic acid is neutralized by metal ions] and a resin (B) [a thermoplastic polyamide elastomer with a shore-D harness of 45 to 70 and a flexural elastic modulus of 70 to 300 MPa] in a weight ratio of 50:50 to 90:10 is used as the main constituent of a base resin, the flexural elastic modulus of the composition being 120 to 230 MPa.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a golf ball. More specifically, the present invention relates to a golf ball having good shot feeling and controllability, and excellent resilience performance and flight performance.

[0002]

2. Description of the Related Art In recent years, ionomer resins have been widely used as base resins for covers of golf balls. Particularly, in a two-piece solid golf ball using a solid core, an ionomer resin is almost always used as a base resin for a cover. This is because the ionomer resin has excellent durability, cut resistance, and resilience, and is easy to process.

However, since this ionomer resin has a considerably high hardness and rigidity, compared with balata (trans polyisoprene) which is used as a base resin for a cover of a golf ball having a multi-layered structure having a thread rubber layer, Poor shot feel and controllability (easiness of spinning).

[0004] Therefore, attempts have been made to improve the feel at impact and controllability by softening the ionomer resin by various means. For example, JP-A 1-3
JP-A-08577 and JP-A-5-3931 disclose neutralizing sodium ion or zinc ion of a ternary copolymer of an acrylate ester of an α-olefin and an unsaturated carboxylic acid such as acrylic acid or methacrylic acid with an ionomer resin. It has been proposed that by blending (mixing) a soft ionomer, a high-rigidity ionomer resin is softened to improve the shot feeling and controllability. However, the blend of the soft ionomer resin as described above has a problem that the resilience performance and the flight performance are reduced.

Japanese Patent Application Laid-Open No. 8-155053 discloses that a mixture of an ionomer resin and a low-hardness thermoplastic polyamide elastomer having a Shore D hardness of 20 to 40 is used to ensure resilience while ensuring softness. It has been proposed to improve performance. However, even with this method, although an improvement effect is observed in terms of securing softness, sufficient results have not been achieved in resilience performance and workability.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems in the prior art and provides a golf ball having good hitting feel and controllability, and excellent resilience performance and flight performance. With the goal.

[0007]

Means for Solving the Problems In view of the above circumstances, the present inventor has conducted intensive studies on the resin used for the cover in order to achieve both shot feeling and controllability and resilience performance and flight performance. Resin (A) and Resin (B) Resin (A): at least a part of the carboxyl groups in a terpolymer of ethylene, α, β-unsaturated carboxylic acid and α, β-unsaturated carboxylic acid ester At least a part of the carboxyl groups in the ionomer resin (I) obtained by neutralizing with a metal ion, or a copolymer of the above ionomer resin (I) with ethylene and an α, β-unsaturated carboxylic acid is converted to a metal ion. Ionomer resin obtained by neutralization (II)
Resin (B): A mixture obtained by mixing a thermoplastic polyamide-based elastomer having a Shore D hardness of 45 to 70 and a flexural modulus of 70 to 300 MPa at a weight ratio of 50:50 to 90:10 for the cover. When using a cover with a main component of the base resin and a flexural modulus of 120 to 230 MPa,
The inventors have found that a golf ball having good shot feeling and controllability and excellent rebound performance and flight performance can be obtained, and have completed the present invention.

[0008]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, the ionomer resin (I) in the resin (A) is a terpolymer of ethylene, α, β-unsaturated carboxylic acid and α, β-unsaturated carboxylic acid ester. The ionomer resin (II) is obtained by neutralizing at least a part of the carboxyl groups of the above with a metal ion. At least a part of the carboxyl groups in the copolymer of ethylene and α, β-unsaturated carboxylic acid Is neutralized with a metal ion. Examples of the α, β-unsaturated carboxylic acid as a monomer component of the ionomer resin include acrylic acid, methacrylic acid, fumaric acid, maleic acid, crotonic acid and the like. And acrylic acid and methacrylic acid are particularly preferable. Α, β-
Examples of the unsaturated carboxylate include acrylic acid, methacrylic acid, fumaric acid, methyl such as maleic acid, ethyl, propyl, n-butyl, isobutyl ester and the like, and particularly preferred are acrylic ester, methacrylic ester and the like. . The above ethylene and α, β-
Metals that neutralize at least some of the carboxyl groups in terpolymers of copolymers with unsaturated carboxylic acids or terpolymers of ethylene with α, β-unsaturated carboxylic acids and α, β-unsaturated carboxylic acid esters Examples of the ion include a sodium ion, a lithium ion, a zinc ion, a magnesium ion, and a potassium ion.

[0009] Specific examples of the ionomer resin (I) and the ionomer resin (II) as described above are exemplified by trade names.
For example, ionomer resins commercially available from Mitsui DuPont Polychemicals Co., Ltd. include Himilan 1856 (Na) and Himilan 1855 as terpolymer ionomer resins corresponding to the ionomer resin (I).
(Zn), Himilan AM7316 (Zn), and the like. Examples of the ionomer resin corresponding to the ionomer resin (II) include Hylamine 1605 (Na), Hylamine 1707 (Na), and Hylamine AM7318 (Na).
Hyramine 1706 (Zn), Hyramine AM7315
(Zn), Hylamin AM7317 (Zn), Hylamin AM7311 (Mg), Hylamin AK7320
(K) and the like. Examples of ionomer resins commercially available from DuPont of the United States include Surlyn AD8265 (Na) and Surlyn AD82 as terpolymer ionomer resins corresponding to the ionomer resin (I).
69 (Zn), Surlyn AD8542 (Mg) and the like. As the ionomer resin corresponding to the ionomer resin (II), Surlyn 8920 (Na), Surlyn 8
940 (Na), Surlyn AD8512 (Na), Surlyn 9910 (Zn), Surlyn AD8511 (Z
n), Surlyn AD7930 (Li), Surlyn AD7
940 (Li) and the like. Ionomer resins commercially available from Exxon Chemical Co., Ltd. include ionomer resins corresponding to ionomer resin (II), such as Iotech 8000 (Na) and Iotech 7010 (Z
n) and the like. In addition, Na, Zn, K, Li, described in parentheses after the trade name of the ionomer resin,
Mg and the like indicate the metal species of those neutralizing metal ions. In the present invention, as the resin (A), an ionomer resin neutralized with a monovalent metal ion described above and an ionomer resin neutralized with a divalent metal ion may be used as a mixture.

The resin (B) is a thermoplastic polyamide-based elastomer having a polyamide as a hard segment among thermoplastic elastomers having a portion called a hard segment and a portion called a soft segment in a molecule. Has a Shore D hardness of 45 to 70 and a flexural modulus of 70 to 300 MPa. Specific examples of the thermoplastic polyamide elastomer of the resin (B) include:
For example, those marketed under the trade name DAIAMID by Diesel-Fürs, etc. may be mentioned.

When the Shore D hardness of the thermoplastic polyamide elastomer of the resin (B) is lower than 45, the mixture of the resin (A) with the ionomer resin becomes too soft, and the resilience performance and flight performance are reduced. If the Shore D hardness is 70 or more, the ionomer resin of the resin (A) cannot be sufficiently softened, and good shot feeling and controllability cannot be obtained.

The thermoplastic polyamide elastomer of the resin (B) needs to have a flexural modulus of 70 to 300 MPa for the following reason. That is, when the flexural modulus of the thermoplastic polyamide-based elastomer of the resin (B) is lower than 70 MPa, the mixture of the resin (A) with the ionomer resin becomes too soft, so that the resilience performance and the flight performance are reduced, and the flexural modulus is reduced. When the rate is higher than 300 MPa, the ionomer resin of the resin (A) cannot be sufficiently softened, and good shot feeling and controllability cannot be obtained.

In the present invention, the mixing ratio of the ionomer resin of the resin (A) and the thermoplastic polyamide-based elastomer of the resin (B) is 50:50 to 90:10 by weight, particularly 60:40 to 85: 15, especially 70:30
~ 85: 15 is preferred. When the amount of the ionomer resin of the resin (A) is larger than the above range, the softening cannot be sufficiently achieved, and the properties of the ionomer resin of the resin (A) appear strongly, and the shot feeling and controllability deteriorate. When the amount of the ionomer resin of the resin (A) is less than the above range, the cover becomes too soft, and the resilience performance and the flight performance deteriorate.

In the present invention, the base resin of the cover is mainly composed of a mixture of an ionomer resin of the resin (A) and a thermoplastic polyamide-based elastomer of the resin (B), and the cover containing the same has a flexural elasticity. Rate is 120-2
It is required to be 30 MPa for the following reason. That is, when the bending elastic modulus of the cover is lower than 120 MPa, the cover becomes too soft and the spin amount increases too much, so that the flight performance and cut resistance are reduced,
When the flexural modulus is higher than 230 MPa, the cover becomes hard and an appropriate amount of back spin cannot be obtained, so that the controllability and the feel at impact deteriorate. The cover is mainly composed of a mixture of an ionomer resin of the resin (A) and a thermoplastic polyamide-based elastomer of the resin (B), and in many cases, only a small amount of titanium dioxide or barium sulfate is added thereto. The flexural modulus is substantially the same as the flexural modulus of a mixture of the ionomer resin of the resin (A) and the thermoplastic polyamide elastomer of the resin (B).

In the present invention, as described above, the mixing ratio between the ionomer resin of the resin (A) and the thermoplastic polyamide elastomer of the resin (B) is 50:50 by weight.
In this case, the ionomer resin of the resin (A) is appropriately selected or the ionomer resin (I) and the ionomer resin (II) are selected so that the bending elastic modulus of the obtained cover is 120 to 230 MPa. ) Is preferably used in combination.

As described above, a mixture of the ionomer resin of the resin (A) and the thermoplastic polyamide-based elastomer of the resin (B) in a weight ratio of 50:50 to 90:10 is obtained by terpolymerization of the resin (A). Since the system ionomer resin (I) acts as a compatibilizer, it has good workability as a so-called cover material, and is used as a main component when preparing a cover composition or as a core material. Excellent workability when coating.

In preparing the cover composition, the mixture is usually mixed at 150 to 250 ° C. using an internal mixer such as a kneading twin screw extruder, a Banbury or a kneader.
By heating and mixing for 0.5 to 15 minutes. The cover composition forming the cover, if necessary, various additives, for example, pigments, dispersants, antioxidants,
An ultraviolet absorber, a light stabilizer and the like can be added.

In the present invention, as the core, any of a solid golf ball core (solid core) and a multilayer golf ball core having a rubber thread layer (thread wound core) can be used.

The solid core may be a single-layer core or a multilayer core having two or more layers.
For example, as a core for a two-piece ball, for 100 parts by weight of polybutadiene, an α, β-monoethylenically unsaturated carboxylic acid such as acrylic acid or methacrylic acid or a metal salt thereof, or a functional group such as trimethylolpropane trimethacrylate is used. Vulcanizing agent (crosslinking agent) composed of monomers, etc.
10 to 60 parts by weight alone or in total, 10 to 30 parts by weight of a filler such as zinc oxide and barium sulfate, and 0.5 to 5 parts by weight of a peroxide such as dicumyl peroxide,
If necessary, a rubber composition further containing 0.1 to 1 part by weight of an antioxidant is press-vulcanized (cross-linked), for example, to 1%.
Heat and compress at a temperature of 40 to 170 ° C for 10 to 40 minutes,
What was obtained by shape | molding into a spherical vulcanizate can be used.

The thread wound core is composed of a center and a thread rubber wound around the center. The center can be either a liquid or a rubber. As the rubber center, for example, one obtained by vulcanizing a rubber composition similar to that of the solid core can be used. Conventionally used thread rubbers can be used.For example, a natural rubber or a mixture of a natural rubber and a synthetic polyisoprein mixed with an antioxidant, a vulcanization accelerator, sulfur, etc. is added. What was obtained by sulfurizing can be used. However, these solid cores and thread-wound cores are merely examples, and the present invention is not limited to these examples.

The method of covering the core with the cover is not particularly limited, and can be performed by a usual method.
For example, the cover composition is preliminarily formed into a hemispherical shell-shaped half shell, and the core is wrapped using two of the half shells.
A method of press-molding at ~ 170 ° C for 1 to 15 minutes or a method of wrapping the core by injection molding the cover composition directly on the core is employed. The thickness of the cover is usually about 1 to 4 mm. Then, when forming the cover, dimples are formed on the ball surface as necessary, and after the cover is formed, paint finishing, stamping, and the like are performed as necessary.

FIG. 1 is a cross-sectional view schematically showing one example of the golf ball of the present invention. The golf ball shown in FIG. 1 has a core 1 made of a vulcanized molded product of a rubber composition called a solid core, and And a cover 2 that covers the golf ball. The core 1 is not particularly limited to a specific one. For example, a vulcanized molded product of a rubber composition containing polybutadiene as a main material as described above is used, and a cover 2 covering the same is made of the resin (A). A flexural modulus of 120 to 230 MPa containing a mixture of an ionomer resin and a thermoplastic polyamide-based elastomer of resin (B) at a weight ratio of 50:50 to 90:10 as a main component of the base resin.
a) formed from the cover composition. Reference numeral 2a denotes a dimple provided on the cover 2.

In the golf ball shown in FIG.
Is composed of a vulcanized molded product of a rubber composition having a one-layer structure. Alternatively, for example, polybutadiene may be further added around an inner core composed of a vulcanized molded product of a rubber composition containing polybutadiene as a main material. The core may be a two or more-layer core having an outer core formed of a vulcanized molded product of the rubber composition to be formed, or a wound core. Further, an intermediate layer may be provided between the core and the cover, or an auxiliary cover layer may be provided outside or inside the cover, as long as the effects of the present invention are not impaired. The dimples 2a are provided on the cover 2 of the golf ball in an appropriate number and in an appropriate form so that desired or desired characteristics can be obtained. The surface of the ball is painted or marked accordingly.

[0024]

Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to only these examples.

Examples 1 to 4 and Comparative Examples 1 to 4 The golf balls of Examples 1 to 4 and Comparative Examples 1 to 4 were produced through the following steps.

Preparation of Core Zinc acrylate was added to 100 parts by weight of polybutadiene [BR-18 (trade name), manufactured by Nippon Synthetic Rubber Co., Ltd.].
Parts by weight, zinc oxide 5 parts by weight, tungsten 10 parts by weight,
0.5 parts by weight of sulfur compound, dicumyl peroxide
A rubber composition containing 5 parts by weight and 0.5 part by weight of an antioxidant (Yoshinox 425 (trade name), manufactured by Yoshitomi Pharmaceutical Co., Ltd.) is vulcanized and molded by heating and compressing at 160 ° C. for 15 minutes. A solid core having a diameter of 39.0 mm was obtained.

Preparation of Cover Composition The compounding materials having the compositions shown in Tables 1 and 2 were mixed with a twin-screw kneading extruder to prepare a pellet-shaped cover composition. The amounts of each component in the table are parts by weight, and details of the components indicated by trade names in the table are shown after Table 2. Extrusion conditions were: screw diameter 45 mm, screw rotation speed 200 rpm, screw L / D = 35,
The formulation was heated to 220-260C at the extruder die. The flexural modulus of the obtained cover composition was measured. The results are also shown in Tables 1 and 2. The flexural modulus of the cover composition was measured according to ASTM D-747 after storing a hot-pressed sheet having a thickness of about 2 mm prepared from each cover composition at 23 ° C for 2 weeks. The Shore D hardness of the material used is ASTM D-
The flexural modulus was measured according to ASTM D-747 in the same manner as described above.

[0028]

[Table 1]

[0029]

[Table 2]

* 1: Himilan 1855 (trade name) Zinc ion neutralized ethylene-butyl acrylate-methacrylic acid terpolymer copolymer ionomer resin manufactured by Du Pont-Mitsui Polychemicals Co., Ltd., Shore D hardness = 54, flexural modulus = 87 MPa * 2: Himilan 1605 (trade name) Sodium ion-neutralized ethylene-methacrylic acid copolymer ionomer resin manufactured by Mitsui Dupont Polychemical Co., Ltd., Shore D hardness = 61, flexural modulus = 295 MPa * 3: Daiamide E47S ( (Product name) Thermoplastic polyamide-based elastomer manufactured by Die Selfies, Shore D hardness = 47, Flexural modulus = 130MP
a * 4: DAIAMID E55S (trade name) Thermoplastic polyamide elastomer manufactured by DAISEL FULS, Shore D hardness = 55, flexural modulus = 210MP
a

* 5: Surlyn AD8269 (trade name) Zinc ion neutralized ethylene-butyl acrylate-methacrylic acid terpolymer copolymer ionomer resin manufactured by DuPont, Shore D hardness = 36, flexural modulus = 26 MPa * 6: Surlyn AD8511 (trade name) Zinc ion neutralized ethylene-methacrylic acid copolymer ionomer resin manufactured by DuPont, Shore D hardness = 59,
Flexural modulus = 221 MPa * 7: Surlyn AD8512 (trade name) Sodium ion neutralized ethylene-methacrylic acid copolymer ionomer resin manufactured by DuPont, Shore D hardness =
61, flexural modulus = 272 MPa * 8: Pebax 2533 (trade name) polyamide elastomer manufactured by Toray Industries, Ltd., Shore D hardness = 25, flexural modulus = 20 MPa

Preparation of Golf Ball The above-mentioned cover composition was directly injection-molded onto the above-mentioned solid core to cover the above-mentioned solid core, and the obtained ball was painted with paint to obtain an outer diameter of 42.7 mm. ,
A golf ball having a ball weight of 45.4 g was produced.

The obtained golf ball was examined for ball compression, ball initial speed, flight distance with a driver, shot feeling, and controllability in approach. The results are shown in Tables 3 and 4.

Ball compression: According to the PGA measurement method.

Ball initial velocity: According to the R & A initial velocity measuring method.

Flight distance: A driver (Wood No. 1 club) is attached to a swing robot manufactured by True Temper, and the ball is hit at a head speed of 45 m / s, and the distance (carry) to the drop point is measured.

Hit feeling: Evaluated by an actual hit test with a driver (Wood No. 1 club) by 10 top professionals. The evaluation criteria are as follows, and when the evaluation results are displayed in the table, the same symbols are used. In that case, eight or more out of the ten people who gave the evaluation gave the same evaluation. Is shown.

Evaluation criteria: ：: soft and good △: slightly hard × H: hard and bad × S: soft and bad

Controllability: Evaluated by approach shots with an iron ninth club of 10 top professionals.
The evaluation criteria are as follows, and when the evaluation results are displayed in the table, the same symbols are used. In that case, eight or more out of the ten people who gave the evaluation gave the same evaluation. Is shown.

Evaluation criteria: ：: Spin easily applied, good Δ: Spin slightly applied, but insufficient X: Spin hardly applied, poor

[0041]

[Table 3]

[0042]

[Table 4]

As is clear from the comparison between the ball characteristics of Examples 1 to 4 shown in Table 3 and the ball characteristics of Comparative Examples 1 to 4 shown in Table 4, Examples 1 to 4 have good shot feeling and controllability. And excellent resilience performance and flight performance. That is, as shown in Table 3, in Examples 1 to 4, both the feel at impact and the controllability were evaluated as “、”, the feel at impact and the controllability were good, the ball initial velocity and the flight distance were large, and the rebound performance was high. And flight performance was excellent.

On the other hand, in Comparative Examples 1-4, the shot feeling,
The characteristics were inferior in any one or more of controllability, rebound performance, and flight performance. That is, Comparative Example 1 does not contain the thermoplastic polyamide-based elastomer of the resin (B) as shown in Table 2, so that the shot feeling and controllability are not sufficient as shown in Table 4, and the flight distance is also sufficient. However, in Comparative Example 2, since the cover had a low flexural modulus as shown in Table 2, the cover became too soft,
As shown in Table 4, the shot feeling was poor and the flight distance was short. Also, in Comparative Example 3, as shown in Table 2, the cover had a low flexural modulus, so the cover was too soft, and as shown in Table 4, the shot feeling was poor, and the ball initial speed and flight distance were small, and the rebound performance was small. And flight performance was poor. Further, in Comparative Example 4, as shown in Table 2, since the cover had a large flexural modulus, the cover was too hard, and as shown in Table 4, the shot feeling was poor and the controllability was poor.

[0045]

As described above, according to the present invention, a golf ball having good shot feeling and controllability and excellent resilience performance and flight performance can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing one example of a golf ball of the present invention.

[Explanation of symbols]

 1 core 2 cover

Claims (2)

[Claims] 1. A golf ball having at least a core and a cover, wherein the cover comprises a mixture of the following resin (A) and resin (B) in a weight ratio of 50:50 to 90:10 as a main component of the base resin. A golf ball comprising: a cover; and a flexural modulus of the cover of 120 to 230 MPa. Resin (A): Obtained by neutralizing at least a part of carboxyl groups in a terpolymer of ethylene, α, β-unsaturated carboxylic acid and α, β-unsaturated carboxylic acid ester with metal ions. An ionomer resin (I) or an ionomer resin obtained by neutralizing at least a part of carboxyl groups in a copolymer of the above ionomer resin (I) with ethylene and an α, β-unsaturated carboxylic acid with a metal ion ( II)
Resin (B): a thermoplastic polyamide elastomer having a Shore D hardness of 45 to 70 and a flexural modulus of 70 to 300 MPa. 2. The golf ball according to claim 1, wherein the resin (A) is a mixture of an ionomer resin neutralized with a monovalent metal ion and an ionomer resin neutralized with a divalent metal ion.