JPH11347151A - Golf ball - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a golf ball which has excellent repulsive elasticity and provides a good impact feeling. SOLUTION: A mixture, which is composed of (A):(B):(C)=1 to 70:10 to 80:10 to 90 in the weight ratio of the compounding ratios of (A) a thermoplastic polyamide elastomer of 20 to 50 in Shore hardness and 10 to 150 MPa in modulus of elasticity in bending, (B) a binary copolymer ionomer formed by neutralizing at least part of the carboxyl group of an ethylene/unsatd. carboxylic acid copolymer with metal ions, (C) a ternary copolymer ionomer formed by neutralizing at least part of the carboxyl group of an ethylene/unsatd. carboxylic acid and unsatd. carboxylate ternary copolymer with the metal ions and (D) an epoxylated diene block copolymer and in which the content of (D) is 1 to 40 pts.wt. per 100 pts.wt. total of (A)+(B)+(C), is used as the base material polymer of the cover 2 of the golf ball.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a golf ball, and more particularly, to a golf ball having excellent rebound resilience and good hit feeling when hit.

[0002]

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

However, since this ionomer has a considerably high hardness and rigidity, it is used as a base resin for a cover of a multi-layer golf ball having a thread rubber layer which is generally called a thread wound golf ball. Compared to trans polyisoprene), it is inferior in the feeling (hit feeling) and controllability (easiness of spinning) when hit.

[0004] Therefore, attempts have been made to improve the feel and controllability at the time of impact by softening the ionomer by various means. For example, JP-A-1-308577 and JP-A-5-3931 disclose that an ionomer contains an α-olefin and acrylic acid,
Blend (mixing) soft ionomers of terpolymer of unsaturated carboxylic acid such as methacrylic acid and acrylate ester with sodium ion neutralization or zinc ion neutralization
By softening the high-rigidity ionomer,
It has been proposed to improve the feel and control when hitting.

However, in the case of using a blend of the soft ionomer as described above, there is a problem that the resilience performance and the flight performance are reduced.

JP-A-6-299052 proposes to improve flexibility by adding a graft-modified ethylene / (meth) acrylate copolymer or an ionomer thereof. However, the flexibility and rebound resilience were not sufficient, and the compatibility between the above-mentioned thermoplastic elastomer and the ionomer was not sufficiently satisfactory.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems in the prior art and has excellent rebound resilience.
It is another object of the present invention to provide a golf ball having a good feel when hit.

[0008]

The present inventors have conducted intensive studies to solve the above-mentioned problems. As a result, the base resin of the cover of the golf ball was changed to the following (A) to (D) (A) Shore. D hardness is 20 to 50 and flexural modulus is 1
0 to 150 MPa thermoplastic polyamide elastomer (B) Binary copolymer ionomer obtained by neutralizing at least a part of the carboxyl groups of an ethylene / unsaturated carboxylic acid copolymer with metal ions (C) Ethylene / unsaturated carboxylic acid A terpolymer ionomer in which at least a part of the carboxyl group of the unsaturated carboxylic acid ester terpolymer is neutralized with metal ions; (D) an epoxidized diene block copolymer; ) To (D) are (A)
(A) :( B):
(C) = 1 to 70:10 to 80:10 to 90, and (D) to 1 to 40 parts by weight based on 100 parts by weight of the total of (A) + (B) + (C) Found that a golf ball having excellent rebound resilience, being soft, and having a good feeling at the time of impact can be obtained, and completed the present invention.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the above (A) to (A)
The thermoplastic polyamide-based elastomer (A) of the four components (D) has 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. The thermoplastic polyamide elastomer (A) has a Shore D hardness of 20 to 50,
Preferably it is 25 to 45, and the flexural modulus is 10 to
The pressure is 150 MPa, preferably 20 to 130 MPa. Since this thermoplastic polyamide-based elastomer has a relatively low hardness and a high flexural modulus, it contributes to the improvement of rebound resilience, and when this thermoplastic polyamide-based elastomer is blended, it is almost the same as a blend cover between ordinary ionomers. Even if the hardness is high, the flexural modulus increases, and the resilience of the cover increases while maintaining flexibility. Specific examples of the thermoplastic polyamide-based elastomer (A) include, for example, those commercially available from Toray Industries, Inc. under the trade name of “PEBAX”. In the above thermoplastic polyamide-based elastomer, the reason that the Shore D hardness is required to be 20 to 50 or the flexural modulus is 1
For the reason that it is necessary to be 0 to 150 MPa,
This will be described later in detail.

In the present invention, the binary copolymer-based ionomer (B) neutralizes at least a part of the carboxyl groups in the copolymer of ethylene and α, β-unsaturated carboxylic acid with metal ions. Since the binary copolymer ionomer has a high flexural modulus, it has the effect of contributing to the improvement of the rebound resilience of the cover. As the binary copolymer ionomer, those having a flexural modulus of 200 MPa or more are particularly preferable from the above viewpoint.

The terpolymer ionomer (C) is composed of ethylene, α, β-unsaturated carboxylic acid and α, β-unsaturated carboxylic acid.
It is obtained by neutralizing at least a part of the carboxyl groups in the terpolymer with the β-unsaturated carboxylic acid ester with a metal ion. This terpolymer ionomer is composed of other three components ( Since it acts as a compatibilizer when blending A), (B) and (D), it is indispensable in the present invention.

As the α, β-unsaturated carboxylic acid of the above-mentioned binary copolymer ionomer or terpolymer ionomer, for example, acrylic acid, methacrylic acid, fumaric acid,
Maleic acid, crotonic acid and the like can be mentioned, and acrylic acid and methacrylic acid are particularly preferable. Examples of the α, β-unsaturated carboxylic acid ester include, for example, methyl, ethyl, propyl, n-butyl, isobutyl esters such as acrylic acid, methacrylic acid, fumaric acid, and maleic acid, and particularly acrylic acid esters And methacrylic acid esters are preferred. At least one of the carboxyl groups in the above-mentioned copolymer of ethylene and α, β-unsaturated carboxylic acid or terpolymer of ethylene, α, β-unsaturated carboxylic acid and α, β-unsaturated carboxylic acid ester Examples of metal ions that partially neutralize include sodium ions, lithium ions, zinc ions, magnesium ions, and potassium ions.

[0013] Specific examples of the above-mentioned (B) binary copolymer-based ionomers are exemplified by trade names. For example, as ionomers commercially available from Mitsui Dupont Polychemical Co., Ltd., Himilan 1555 (Na) and Himilan 155 are available.
7 (Zn), Himilan 1601 (Na), Himilan 1605 (Na), Himilan 1706 (Zn), Himilan 1707 (Na), Himilan AM7315 (Z
n), Himilan AM7317 (Zn), Himilan A
M7311 (Mg), Himilan AK7320 (K), and the like, and ionomers commercially available from DuPont of the United States include Surlyn AD8511 (Zn), Surlyn 8945 (Na), Surlyn 8920 (Na),
Surlyn 8940 (Na), Surlyn 9910 (Z
n), Surlyn AD7930 (Li), Surlyn AD7
940 (Li) and the like.

Further, specific examples of the terpolymer ionomer (C) are exemplified by trade names. For example, as ionomers commercially available from Mitsui Dupont Polychemical Co., Ltd., Himilan 1856 (Na) and Himilan 18 are available.
55 (Zn), Himilan AM7316 (Zn), and the like, and ionomers commercially available from DuPont, USA include Surlyn AD8265 (Na), Surlyn AD8269 (Na), and Surlyn AD8542 (M).
g) and the like. In addition, Na, Zn, K, Li, and Mg described in parentheses after the trade name of the ionomer.
Etc. indicate the metal species of those neutralizing metal ions.

In the present invention, the epoxidized diene-based block copolymer (D) is obtained by epoxidizing a double bond derived from a conjugated diene compound of a block copolymer or a partially hydrogenated block copolymer. is there. The block copolymer serving as the base is composed of at least one polymer block A mainly composed of a vinyl aromatic compound and at least one block.
And a polymer block B mainly composed of a kind of conjugated diene compound. In addition, the partially hydrogenated block copolymer is obtained by hydrogenating the above block copolymer.

Examples of the vinyl aromatic compound constituting the block copolymer include styrene, α-methylstyrene, vinyltoluene, p-tert-butylstyrene,
One or two of 1,1-diphenylethylene and the like
More than one kind can be selected and adopted, and styrene is particularly preferable.

Examples of the conjugated diene compound include butadiene, isoprene, 1,3-pentadiene,
1 out of 2,3-dimethyl-1,3-butadiene, etc.
Species or two or more species can be selectively adopted, among which butadiene,
Isoprene and combinations thereof are preferred. Specific examples of the epoxidized diene-based block copolymer (D) include, for example, those marketed by Daicel Chemical Industries, Ltd. under the trade name of “Epofriend”.

In the present invention, the thermoplastic polyamide-based elastomer (A) has a Shore D hardness of 20 to 50.
It is necessary that the Shore D hardness of the thermoplastic polyamide elastomer is lower than 20,
The mixture of the (B) binary copolymer ionomer, the (C) terpolymer ionomer and the (D) epoxidized diene block copolymer becomes too soft,
When the rebound resilience is reduced and the Shore D hardness is higher than 50, the binary copolymer ionomer (B), the terpolymer ionomer (C) and the epoxidized diene block copolymer (D) are used. This is because the mixture with the coalescence cannot be sufficiently softened, and the feeling at the time of impact cannot be improved. Further, it is necessary that the thermoplastic polyamide-based elastomer (A) has a flexural modulus of 10 to 150 Mpa because the thermoplastic polyamide-based elastomer has a flexural modulus of 10 MPa.
When it is lower than Mpa, the mixture with the binary copolymer-based ionomer (B), the terpolymer-based ionomer (C) and the epoxidized diene-based block copolymer (D) becomes too soft, When the rebound resilience is reduced and the flexural modulus is higher than 150 MPa, the binary copolymer ionomer (B), the terpolymer ionomer (C) and the epoxidized diene block copolymer (D) are used. This is because the mixture with the coalescence cannot be sufficiently softened, and the feeling at the time of impact cannot be improved.

In the present invention, (A) a thermoplastic polyamide-based elastomer, (B) a binary copolymer-based ionomer, and (C) a terpolymer-based ionomer;
The base resin of the cover is composed of a mixture with the epoxidized diene-based block copolymer (D), and the mixing ratio of the four components is as follows: (A), (B), and (C) (A) :( B) :( C) = 1-70: 10-8 by ratio
0:10 to 90, preferably 3 to 18:20 to 6
0: 22-77, (D) is the above (A) + (B) +
It is 1 to 40 parts by weight, preferably 1 to 20 parts by weight, based on 100 parts by weight in total of (C). For example, when the mixing ratio of the above (A) is less than the above range, the effect of improving softening and rebound resilience is not sufficient, and when the mixing ratio of the above (A) is more than the above range, it becomes soft. Too much and the rebound resilience decreases. When the blending ratio of the above (B) is less than the above range, the flexural modulus becomes too low and the rebound resilience decreases, and when the blending ratio of the above (B) is more than the above range, it becomes too hard. Becomes inflexible. If the compounding ratio of the above (C) is less than the above range, the compatibility with (A), (B) and (D) becomes poor, resulting in poor appearance, and the above (C)
When the compounding ratio of is larger than the above range, it becomes too soft, and sufficient rebound resilience cannot be obtained. And (D)
Is less than the above range, (A),
The compatibility with (B) and (C) becomes poor, and the appearance becomes poor. When the blending ratio of (D) is more than the above range, the composition becomes too soft to obtain sufficient rebound resilience. I can't.

In the present invention, the thermoplastic polyamide elastomer (A), the binary copolymer ionomer (B), the terpolymer ionomer (C) and the epoxidized diene block (D) are used. The base resin of the cover is composed of a mixture with the copolymer, but the whole resin component of the cover may be composed solely of the substrate resin. May be added to form the resin component of the cover. However, it is preferable that the base resin accounts for 90% by weight or more of all resin components of the cover. The cover containing the base resin preferably has a Shore D hardness of 45 to 65 and a flexural modulus of 100 to 210 MPa. If the Shore D hardness of the cover is lower than 45, the cover may be too soft and the rebound resilience may be reduced. If the Shore D hardness of the cover is higher than 65, the cover may lack flexibility. The cover has a flexural modulus of 100 MPa.
If the elastic modulus is lower than the above range, the resilience may be lacking. If the flexural modulus is higher than 210 MPa, the elasticity may be lacking.

In preparing the cover composition for forming the cover, a base resin composed of the above four components (A) to (D) is used as a main material, and various additives, if necessary, For example, a pigment, a dispersant, an antioxidant, an ultraviolet absorber, a light stabilizer, etc. are appropriately added, and usually, an internal mixer such as a kneading twin-screw extruder, a Banbury, or a kneader is used. It is performed by heating and mixing for 0.5 to 15 minutes.

In preparing the cover composition, additives such as pigments are appropriately added as described above. However, since the amount thereof is small, the flexural modulus of the cover is as described in (A) to (C) above.
It is almost the same as the flexural modulus when the four components (D) are mixed.

A golf ball is produced by coating the above-mentioned cover directly or via another layer on the core. The core is a solid golf ball core (solid core), a multilayer having a rubber thread layer. Any of golf ball cores (thread-wound cores) having a structure may 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. A vulcanizing agent (crosslinking agent) composed of a monomer or the like alone or in a total of 10 to 60 parts by weight, zinc oxide,
1-30 parts by weight of a filler such as barium sulfate and tungsten, and 0.5% of a peroxide such as dicumyl peroxide.
To 5 parts by weight, and if necessary, an antioxidant in an amount of 0.1 to 5 parts by weight.
Press vulcanization (crosslinking) of a rubber composition containing 1 to 1 part by weight
For example, at a temperature of 140 to 170 ° C., 10 to 40
What was obtained by heating under pressure for a minute and forming into a spherical vulcanized body can be used.

The thread wound core is composed of a center and a thread rubber wound around the center, and the center can be either a liquid system or a rubber system. As the rubber-based center, one obtained by vulcanizing a rubber composition similar to that of the solid core can be used.

As the thread rubber, those conventionally used can be used. For example, rubber obtained by blending natural rubber or a mixture of natural rubber and synthetic polyisoprene with an anti-aging agent, a vulcanization accelerator, sulfur, etc. Those obtained by vulcanizing the composition can be used. However, these solid cores and wound cores are merely examples,
It is not limited only to these examples.

The cover can be used not only for the outer layer of a two-piece ball but also for an intermediate layer of a two-layer cover type.

The method for coating 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 spherical vulcanized molded product of a rubber composition containing polybutadiene as a main material as described above is used, and a cover 2 for covering the same is made of (A) Shore D
Hardness is 20 to 50 and flexural modulus is 10 to 150 MPa
(B) a binary copolymer ionomer obtained by neutralizing at least a part of the carboxyl group of the ethylene / unsaturated carboxylic acid copolymer with a metal ion, and (C) an ethylene / unsaturated carboxylic acid Specific blending ratio of terpolymer ionomer obtained by neutralizing at least a part of carboxyl groups of acid / unsaturated carboxylic acid ester terpolymer with metal ions and (D) epoxidized diene block copolymer Is used as a base resin. Reference numeral 2a denotes a dimple provided on the cover 2.

In the golf ball shown in FIG.
Is composed of a vulcanized molded article of a rubber composition having a one-layer structure. Alternatively, for example, a polybutadiene is further added around the inner core composed of a vulcanized molded article of a rubber composition mainly composed of polybutadiene. Core having a two-layer structure in which an outer core made of a vulcanized molded body of a rubber composition to be formed may be used,
Further, it may be a wound core. Further, an intermediate layer may be provided between the core 1 and the cover 2. Also, cover 2
Not only a single-layer structure but also a multi-layer structure of two or more layers, one of which may be formed by using the above-mentioned specific base resin. The dimples 2a are provided on the cover 2 in an appropriate number and in an appropriate form so that desired or desired characteristics can be obtained. Further, if necessary, paint or marking may be applied to the ball surface. Will be applied.

[0031]

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 6 and Comparative Examples 1 to 4 The golf balls of Examples 1 to 6 and Comparative Examples 1 to 4 were manufactured 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 parts by weight of an antioxidant (Yoshinox 425 (trade name), manufactured by Yoshitomi Pharmaceutical Co., Ltd.) is vulcanized by heating under pressure at 160 ° C. for 15 minutes. As a result, a solid core having an average 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 by a twin-screw kneading extruder to prepare a pellet-shaped cover composition. The unit of the compounding amount of each component in the table is part by weight, and details of those indicated by trade names in the table are shown after Table 2. Extrusion conditions were as follows: screw diameter 45 mm, screw rotation speed 200 rpm, screw L / D = 35.
And the formulation is 220-260 at the die position of the extruder.
Heated to ° C.

[0035]

[Table 1]

[0036]

[Table 2]

* 1: Pebax 2533 (trade name) Thermoplastic polyamide-based elastomer manufactured by Toray Industries, Ltd., Shore D hardness = 25, flexural modulus = 20 MPa * 2: Pebax 4033 (trade name) manufactured by Toray Industries, Inc. Thermoplastic polyamide elastomer, Shore D hardness = 40, flexural modulus = 93 MPa

* 3: Himilan 1555 (trade name) sodium ion neutralized ethylene / methacrylic acid copolymer ionomer manufactured by Mitsui Dupont Polychemicals, Inc.
Shore D hardness = 57, flexural modulus = 205 MPa * 4: Himilan 1706 (trade name) Zinc ion neutralized ethylene / methacrylic acid copolymer ionomer manufactured by DuPont Mitsui Polychemicals, Shore D hardness = 60, flexural elasticity Ratio: 270 MPa * 5: Surlyn AD8511 (trade name) zinc ion neutralized ethylene / methacrylic acid copolymer ionomer manufactured by DuPont, Shore D hardness = 59, flexural modulus = 221 MPa * 6: Surlyn 8945 (trade name) Dupont Zinc ion neutralized ethylene / methacrylic acid copolymer ionomer, Shore D hardness = 61, flexural modulus = 272 MPa

* 7: Himilan 1855 (trade name) Zinc ion neutralized ethylene / butyl acrylate / methacrylic acid terpolymer copolymer ionomer manufactured by Mitsui DuPont Polychemicals, Shore D hardness = 54, flexural modulus = 87 MPa * 8: Surlyn AD8542 (trade name) Magnesium ion neutralized ethylene / butyl acrylate / methacrylic acid terpolymer copolymer ionomer manufactured by DuPont, Shore D hardness = 44, flexural modulus = 35 MPa

* 9: Epofriend A1010 (trade name) Epoxidized diene block copolymer manufactured by Daicel Chemical Industries, Ltd., Shore A hardness = 67 * 10: Himilan 1557 (trade name) Mitsui Dupont Polychemical Co., Ltd. ) -Made ionomer of zinc ion neutralized ethylene / methacrylic acid copolymer, Shore D hardness = 57, flexural modulus = 215 MPa * 11: Himilan 1707 (trade name) Sodium ion neutralized ethylene made by Mitsui Dupont Polychemical Co., Ltd. -Methacrylic acid copolymer ionomer,
Shore D hardness = 62, flexural modulus = 275 MPa

In the above composition for a cover, Epofriend A1010 (trade name) belongs to the epoxidized diene block copolymer (D), and (A) + of Epofriend A1010 (trade name) The mixing ratio of the total amount of (B) + (C) to 100 parts by weight is In the case of 1, about 17.6 parts by weight [15 / (15 + 15 + 15 + 40
= 85) × 100 × 17.6 parts by weight], No. In the case of 2, about 5.3 parts by weight [5 / (15 + 30 + 30 + 20 = 9
5) × 100 ≒ 5.3 parts by weight], In the case of 3, about 5.
3 parts by weight [5 / (10 + 25 + 30 + 30 = 95) × 1
00 ≒ 5.3 parts by weight]. In the case of No. 4, about 11.1 parts by weight [10 / (10 + 25 + 25 + 30 = 90) × 100]
{11.1 parts by weight] ”, No. In the case of 5, about 11.1 parts by weight [10 / (10 + 25 + 25 + 30 = 90) × 100}
11.1 parts by weight].

The Shore D hardness and flexural rigidity of the obtained cover composition were measured. The results are also shown in Tables 1 and 2 together with the composition of the cover composition. Shore D
The methods for measuring the hardness and the flexural rigidity are as follows.

Shore D hardness: A hot press molded sheet having a thickness of about 2 mm produced from each cover composition is stored at 23 ° C. for 2 weeks, and then measured according to ASTM D-2240.

Flexural rigidity: A heat-pressed sheet having a thickness of about 2 mm and made from each of the cover compositions was 23
After storage at 2 ° C. for 2 weeks, the measurement is performed according to ASTM D-747.

The above composition for cover No. Nos. 1 to 5 are used for forming the covers of the golf balls of Examples 1 to 5, respectively. Nos. 6 to 9 are used to form covers of the golf balls of Comparative Examples 1 to 4, respectively. In the golf ball of Example 6, the cover had a two-layer structure, and the cover composition N
o. And using the cover composition N on its outer cover
o. 6 was used.

Preparation of Golf Ball The above-mentioned composition for a cover was directly injection-molded on the above-mentioned solid core to cover the above-mentioned solid core, and the obtained ball was painted with paint to have an outer diameter of 42.7 mm.
Thus, a golf ball having a ball weight of 45.4 g was produced. However, in the case of Example 6, the composition No. for the cover was placed on the solid core. 3 is formed by injection molding to form an inner cover, and the cover composition No. 3 is formed on the inner cover. 6 was injection molded to form an outer cover, thereby producing a golf ball.

The obtained golf ball was examined for ball compression, initial ball speed, flight distance with a driver, and feeling when hit. The results are shown in Tables 3 and 4 together with the cover composition used. In addition, in the table | surface of a composition for covers, the No. Indicated by Also,
The composition for cover No. 6 of Example 6 In the display of Table 3 of “No. 3”, “3 + 6” is used. No. 3 and the cover composition No. 3 was used for the outer cover. 6 is used. In Example 6, the thickness of the inner cover was 0.7 mm, and the thickness of the outer cover was 1.2 mm.
Because of the layer structure, the thickness of each of those covers is 1.8
5 mm. The methods for measuring and evaluating the ball characteristics are as follows.

Ball compression: According to the PGA measurement method.

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

Flight distance with a driver: A 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 a drop point is measured. In displaying the measurement results in the table, this “flying distance with a driver” is simply represented as “flying distance”.

Feeling at the time of hitting: The feeling at the time of hitting was evaluated as follows based on the questionnaire given to ten professional and top amateur golfers. In displaying the evaluation results in the table, this "feel at the time of impact" is simplified and simply shown as "feel".

○: 8 to 10 △: 4 to 7 ×: 0 to 3

[0053]

[Table 3]

[0054]

[Table 4]

As is clear from the comparison between the ball characteristics of Examples 1 to 6 shown in Table 3 and the ball characteristics of Comparative Examples 1 to 4 shown in Table 4, Examples 1 to 6 show that the ball initial speed and the flight distance are different. It was large, had a good feeling, had excellent rebound resilience, was soft, and had a good feeling when hit.

On the other hand, in Comparative Example 1, the base resin of the cover was composed of only the ionomer, so that the rebound resilience was lower, the flight distance with the driver was smaller, and the The rings were not satisfactory enough. Further, in Comparative Example 2, the cover was low in hardness and the cover was too soft and flexible, but the rebound resilience was low and the flight distance was small because the blending ratio of the binary copolymer type ionomer (B) was low. Was.

Comparative Example 3 does not contain the terpolymer ionomer (C) or the epoxidized diene block copolymer (D), and has a high blending ratio of the (B) binary copolymer ionomer. Therefore, the hardness of the cover was high, the cover was too hard and lacked flexibility, and the feel when hitting was hard and poor. Comparative Example 4 does not contain the epoxidized diene-based block copolymer (D) and the compounding ratio of the binary copolymer-based ionomer (B) occupies 80%, so that the cover is too hard. He lacked flexibility and had a hard and bad feel when hitting.

[0058]

As described above, according to the present invention, it is possible to provide a golf ball having excellent rebound resilience and good feeling when hit.

[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 (3)

[Claims] 1. A golf ball having a core and a cover, wherein the base resin of the cover is the following (A) to (D):
(A) Shore D hardness is 20 to 50 and flexural modulus is 1
0 to 150 MPa thermoplastic polyamide elastomer (B) Binary copolymer ionomer obtained by neutralizing at least a part of the carboxyl groups of an ethylene / unsaturated carboxylic acid copolymer with metal ions (C) Ethylene / unsaturated carboxylic acid A terpolymer ionomer in which at least a part of the carboxyl group of the unsaturated carboxylic ester terpolymer is neutralized with a metal ion; (D) an epoxidized diene-based block copolymer (A) to (D) Is (A), (B),
(A) :( B) :( C) = 1 to (C) in weight ratio
70:10 to 80:10 to 90, and (A)
A golf ball, wherein (D) is 1 to 40 parts by weight with respect to 100 parts by weight in total of + (B) + (C). 2. The compounding ratio of (A) to (D) is as follows:
(A), (B), (C) by weight ratio (A):
(B): (C) = 3 to 18:20 to 60:22 to 77, and (D) is 1 to 20 with respect to a total of 100 parts by weight of (A) + (B) + (C). 2. The golf ball according to claim 1, wherein the weight is part by weight. 3. The golf ball according to claim 1, wherein the binary copolymer ionomer (B) has a flexural modulus of 200 MPa or more.