JPH08103516A - Golf ball - Google Patents

Abstract

PURPOSE: To provide a golf ball whose flying distance is large and whose cut resistance is excellent, by making the essential component of the base material polymer of a cover to cover a core a trans-polybutadiene or the like to which a sulfonic acid groups are added, neutralized with a metal ion. CONSTITUTION: The essential component of the base material polymer of a cover 2 to cover a core 1 is made up of a trans-polybutadiene, trans- polyisoprene, trans-polyoctenemer or the mixture of these to which sulfonic acid groups are added, neutralized with a metal ion. The added sulfonic acid groups are neutralized by 100% with zinc ions, and the addition quantity of the sulfonic acid groups to a trans-polybutadiene, trans-polyisoprene, trans- polyoctenemer or the mixture of these are made to be 0.2-3mol%. In addition, the trans-1,4-configuration content of the trans-polybutadiene, trans-polyisoprene or trans-polyoctenemer is made to be more than 60%.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a golf ball,
More specifically, it relates to a golf ball having an excellent shot feeling and controllability, a high resilience performance, a long flight distance and excellent cut resistance.

[0002]

2. Description of the Related Art A thread-wound golf ball containing balata (trans-polyisoprene) as a main component of a cover material is particularly excellent because of its excellent shot feeling and controllability (spin stability, spin spinability). It is favored by people such as players and professional golfers.

This balata is a polymer having both crystallinity and rubber elasticity. From this property, it imparts appropriate hardness and elasticity most preferable as a cover material for a golf ball, and as a result, as described above. While excellent shot feeling and controllability can be obtained, it has many drawbacks as described below.

Repulsion performance is poor and flight distance is not sufficient. This is particularly remarkable when used for the cover of a solid ball such as a two-piece ball, and therefore, it is not generally used for the cover of a solid golf ball.

[0007] Because of insufficient strength, the damage caused by top hitting with an iron is large. That is, the cut resistance is poor.

Since the number of manufacturing steps is large and the manufacturing takes a long time, the productivity is poor. For example, balata covers are vulcanized with sulfur in order to bring physical properties such as strength, repulsion performance, and heat resistance to practical levels, but if the physical properties of the cover are to be maintained, vulcanization must be performed without impairing crystallinity. Therefore, it has to be vulcanized at a temperature lower than the melting point of the crystal (about 60 ° C.), which requires a long time for vulcanization, which is a cause of lowering productivity.

On the other hand, in addition to the above balata, in recent years, ionomer resins, which are metal ion neutralized products of ethylene-unsaturated carboxylic acid copolymers, have been widely used as cover materials for golf balls (Japanese Patent Publication No. Sho 49-49). 27093). Particularly, a cover of a two-piece solid golf ball using a solid core is almost this ionomer resin.

The cover material composed of such an ionomer resin has excellent strength characteristics such as resilience performance, flight distance and cut resistance and workability, and the above-mentioned drawbacks of the balata cover are almost eliminated. Since it has fairly high hardness and rigidity, the shot feeling is too hard compared to the balata cover, and it is easy to slip on the club face surface at the time of hitting, resulting in large variations in spin and poor controllability. I have a point. Therefore, the ionomer resin cover has not been completely replaced with the balata cover for use.

Therefore, this ionomer resin is prepared by various means, for example, from a metal ion neutralized product of a ternary copolymer of ethylene, an acrylic ester and methacrylic acid, as shown in JP-A-1-308577. It has been attempted to soften the high-rigidity ionomer resin by mixing (blending) a low-rigidity ionomer resin with the above-mentioned high-rigidity ionomer resin to improve the shot feeling and controllability. No performance comparable to that is obtained, and the softening described above leads to a decrease in repulsion performance, and satisfactory properties are not obtained.

[0010]

SUMMARY OF THE INVENTION As described above, the problem with golf ball covers up to now is to obtain a material capable of achieving a good balance between shot feel and controllability, as well as resilience performance and cut resistance. That is not done.

Therefore, the present invention has developed a cover material that retains the excellent shot feeling and controllability of a balata cover and has improved resilience performance, cut resistance, workability, etc., and has an excellent shot feeling and control. It is an object of the present invention to provide a golf ball having a high repulsion performance, a long flight distance, and excellent cut resistance.

[0012]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the inventors have found that balata (trans polyisoprene) or balata similar to balata is used as the main component of the base polymer of the cover. Characteristics, that is, by using trans-polybutadiene or trans-polyoctenemer, which is a material having both crystallinity and rubber elasticity, as the polymer main chain and introducing sulfonic acid groups neutralized with metal ions into the polymer main chain When using a polymer material provided with a golf ball, it has a shot feeling and controllability equivalent to those of a balata cover, and has a cover having good repulsion performance, cut resistance, processability, etc. close to an ionomer resin cover. The inventors have found that a ball can be obtained, and have completed the present invention.

That is, the present invention provides a golf ball having a core and a cover covering the core, wherein transpolybutadiene having a sulfonic acid group neutralized with a metal ion is added as a main component of the base polymer of the cover. The present invention relates to a golf ball characterized by using trans polyisoprene, trans polyoctenemer or a mixture thereof.

In the present invention, since the polymer main chain of the main component of the base polymer of the cover is trans-polyisoprene or a polymer similar thereto, the shot feeling and controllability are as good as those of ordinary balata cover balls. The properties described above are achieved, and since a sulfonic acid group neutralized with a metal ion is added to the polymer main chain to give an ionic crosslinked structure, the ionic crosslinked structure allows
The resilience performance and the cut resistance are improved, and the thermoplastic properties of the ionic cross-linking structure provide a satisfactory improvement in processability.

The features of the present invention will be described in detail below. First, the main component of the base polymer of the cover of the present invention is a resin having a double bond in the polymer main chain mainly in the form of trans 1,4-bond and having good rubber elasticity and crystallinity at room temperature. To which a sulfonic acid group neutralized with a metal ion as described above is added.

The resin forming the polymer main chain of the above sulfonated polymer is trans polybutadiene, trans polyisoprene or trans polyoctenemer, and each is represented by the following chemical formula.

Trans polybutadiene:

[0018]

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Trans polyisoprene:

[0020]

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Transpolyoctenemer:

[0022]

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It is preferable that 60% or more, especially 70% or more of the double bonds of these resins are trans 1,4-bonds, because of excellent crystallinity and rubber elasticity.
In addition, all of these resins are commercially available. For example, trans polybutadiene is commercially available from Asahi Kasei Kogyo Co., Ltd.
P049, trade polyisoprene are commercially available from Kuraray Co., Ltd. under the trade name of TP301, and trans polyoctenemer is commercially available from Hüls under the trade name of Bestenemer 8012, which are preferably used in the present invention. Table 1 shows typical characteristic values of these resins.

[0024]

[Table 1]

GPC for molecular weight in Table 1 above is an abbreviation for gel permeation chromatograph, TP3
Regarding 01 (trade name), the molecular weight has not been announced,
It is shown in Table 1 as it is shown in Mooney viscosity.

As shown in Table 1 above, these resins are
Both have high double bond trans fractions,
It has a low glass transition temperature and crystallinity.

In the present invention, a sulfonic acid group neutralized with a metal ion is introduced as a functional group for imparting ionic crosslinkability to the above resin to form a so-called sulfonate-based ionomer resin and then a base polymer for the cover. Used as the main component of.

The addition of the metal ion-neutralized sulfonic acid group to trans polybutadiene, trans polyisoprene or trans polyoctenemer is carried out by dissolving the above resins alone or in a mixture in an organic solvent, adding acetic anhydride and concentrated Add sulfonic acid groups by adding acetylsulfate (acetylsulfate) generated from sulfuric acid to react, and then add metal acetate or hydroxide to this solution to neutralize the solution. You can
In addition to the reaction in the above solution, it can be also carried out by a bulk reaction using an extruder or the like. Since the sulfonic acid group thus introduced is thermally unstable in a free state, it is preferable to completely neutralize it with a metal ion.

As described above, the addition amount of the sulfonic acid group introduced into the polymer main chain of trans polybutadiene, trans polyisoprene or trans polyoctenemer is preferably 0.2 to 3 mol%. The mol% of the added sulfonic acid group as used herein means the number of mols of the added sulfonic acid group per 100 mol of the monomer unit constituting the polymer main chain × 100. When the addition amount of the sulfonic acid group is less than 0.2 mol%, the formation of ionic crosslinks is insufficient, and the repulsion performance and cut resistance cannot be sufficiently improved, while the addition amount of the sulfonic acid group is insufficient. When it is more than 3 mol%, the thermoplasticity (fluidity during heating) is impaired, and molding of the cover may become difficult.

Examples of the neutral metal ion species for the sulfonic acid group include alkali metals such as lithium, sodium and potassium, alkaline earth metals such as calcium and magnesium, transition metals such as zinc or cobalt, copper and nickel. , Ions of various metals. Of these metal ions, a neutralized product with zinc ions is particularly preferable because it has good melt processability and an excellent effect of improving strength.

The cover of the golf ball of the present invention comprises:
The above-mentioned resin such as trans-polyisoprene, trans-polybutadiene, or trans-polyoctenemer having a sulfonic acid group neutralized with a metal ion is used alone or as a mixture of two or more kinds as a main component of the base polymer, According to the above, resins or rubbers other than the above, various additives are added, and mixed by an internal mixer such as Banbury, a kneader, a mixing roll, an extruder or the like,
For example, it is formed using a cover composition molded into a pellet shape or a sheet shape.

As the base polymer for the cover, the above-mentioned metal ion-neutralized sulfone group-added trans polybutadiene, trans polyisoprene, trans polyoctenemer or a mixture thereof is used by adding another resin or rubber. In this case, the content of transpolybutadiene, transpolyisoprene, transpolyoctenemer or a mixture thereof having a sulfone group neutralized with the metal ion is 50% by weight or more, particularly 70% by weight or more in the base polymer. It is preferable.

When other resins or rubbers are added as described above, examples of the resins or rubbers include high styrene resins such as Nipol 2007J (trade name) manufactured by Nippon Zeon Co., Ltd., and Mitsui DuPont Poly. Ethylene such as High Milan (trade name) manufactured by Chemical Co., Ltd.
Unsaturated carboxylic acid ionomer resin, ethylene-acrylic acid ester-unsaturated carboxylic acid copolymer resin such as Nucrel (trade name) manufactured by Mitsui DuPont Polychemical Co., Ltd., maleic anhydride-modified ethylene-ethyl acrylate copolymer resin, Maleic anhydride-modified styrene-hydrogenated butadiene-styrene thermoplastic elastomer, natural rubber, butadiene rubber, ethylene-propylene-diene rubber (EP
DM) and the like.

As various additives, for example,
Examples thereof include pigments such as titanium dioxide, dispersants, melt viscosity modifiers such as zinc stearate, inorganic fillers such as barium sulfate and zinc oxide, antioxidants, ultraviolet absorbers, and light stabilizers.

The cover of the golf ball of the present invention is
It can be applied to any coating of a solid golf ball core (solid core) and a thread wound golf ball core (thread wound core).

The solid core may be a core having a one-layer structure or a multilayer core having two or more layers,
For example, as a core for a two-piece ball, α, β-unsaturated carboxylic acid such as acrylic acid or methacrylic acid or a metal salt thereof, or a functional monomer such as trimethylolpropane trimethacrylate is added to 100 parts by weight of butadiene rubber. 10 to 60 parts by weight of a vulcanizing agent (crosslinking agent) alone or in total, 10 to 30 parts by weight of a filler such as zinc oxide or barium sulfate, and 0.5 to 5 parts of a peroxide such as dicumyl peroxide. A rubber composition containing 0.1 to 1 part by weight of an anti-aging agent is added by, for example, 140 to 170 by press vulcanization (crosslinking).
It is possible to use the one obtained by forming a spherical vulcanized product by heating and compressing at a temperature of 10 ° C. for 10 to 40 minutes.

The thread-wound core comprises a center and a thread rubber wound around the center, and either a liquid-based or rubber-based center can be used. As the rubber center, for example, a center obtained by vulcanizing a rubber composition similar to the solid core can be used.

As the thread rubber, those conventionally used can be used. For example, a rubber obtained by blending natural rubber or a mixture of natural rubber and synthetic isoprene rubber with an antioxidant, a vulcanization accelerator, sulfur and the like. What was obtained by vulcanizing a composition can be used. However,
These solid cores and 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 a usual method can be used.
For example, transpolybutadiene, trans polyisoprene, trans polyoctenemer or a mixture thereof having a sulfonic acid group neutralized with a metal ion as described above is used as a main component of the base polymer, and other necessary additives are added. The composition for a cover appropriately blended is previously molded into a half-shell-shaped half shell, the core is wrapped with two pieces of the shell, and pressure molding is performed at 130 to 170 ° C. for 1 to 15 minutes, or
Alternatively, a method in which the cover composition is directly injection-molded around the core to wrap the core is adopted. The cover usually has a thickness of about 1 to 4 mm. Then, when forming the cover, dimples are formed on the surface of the ball as required, and paint finishing, stamping and the like are also performed as necessary.

Next, the structure of the golf ball of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view schematically showing an example of the golf ball of the present invention. The golf ball shown in FIG. 1 is a thread-wound golf ball. In the figure, 1 is a core composed of a center 1a and thread rubber 1b, 2 is a cover, and 2a is a dimple.

The center 1a and the rubber thread 1b are not limited to particular ones, and those similar to the conventional one can be used. The center 1a may be either liquid type or rubber type. , The rubber thread 1b is the center 1
A core 1 called a wound core is formed by being wound around a in a stretched state. The cover 2 covers the core 1, and the cover 2 is made of trans-polybutadiene or trans-polyisoprene having a sulfonic acid group neutralized with a metal ion as described above.
It is formed from a cover composition containing trans-polyoctenemer or a mixture thereof as a main component of a base polymer.

Although the golf ball shown in FIG. 1 is a thread wound golf ball using a thread wound core, the golf ball of the present invention may be a solid golf ball using a solid core instead of the thread wound core. Good. The solid core may be, for example, a core having a one-layer structure formed of a vulcanized molded product of a rubber composition containing butadiene rubber as a main material, or a rubber composition containing butadiene rubber as a main material. The solid core may have a two-layer structure in which an outer core made of a vulcanized molded product of a rubber composition containing butadiene rubber as a main material is further formed around the inner core made of the vulcanized molded product.

The dimples 2a are provided on the golf ball cover 2 in an appropriate number and manner so that desired or desired characteristics can be obtained.
In addition, paint or marking is applied to the surface of these golf balls, if necessary.

[0044]

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

Examples 1 to 7 and Comparative Examples 1 to 6 Thread wound golf balls of Examples 1 to 7 and Comparative Examples 1 to 6 were produced through the steps shown in the following.

Preparation of core: A liquid center having an outer diameter of 28.1 mm, which is composed of a paste in which barium sulfate is dispersed in water and a cover rubber of 1.7 mm in thickness of vulcanized natural rubber covering the paste, is used as a base. The material rubber is a natural rubber / low cis-isoprene rubber [Shell IR-309 (trade name), Shell Chemical Co., Ltd.] = 50/50 (weight ratio), and is wound with a blend rubber thread rubber, and a thread winding having an outer diameter of 39.5 mm A core was prepared.

Preparation of cover compositions: Tables 2 and 3
A composition for a cover is prepared by kneading the compounding material having the composition shown in (1) with a kneader and a mixing roll,
It was molded into a sheet with a calendar roll to obtain a sheet-shaped cover composition. In addition, in Table 2, Examples 1-7
The compositions of the cover compositions of Preparation Examples 1 to 7 used for the golf ball of No. 1 are shown in Table 3, and Table 3 shows the compositions of the cover compositions of Comparative Preparation Examples 1 to 6 used for the golf balls of Comparative Examples 1 to 6.

Here, of the cover compositions of Comparative Preparation Examples used for the cover of the golf ball of Comparative Example, the cover compositions of Comparative Examples 1 and 2 which serve as a reference for comparison will be described. Comparative Preparation Example 1 Is a composition for a normal balata cover, and Comparative Preparation Example 2 is a composition for a cover using a normal hard ionomer resin, which serve as a reference for comparison.

Preparation of Golf Ball: A hemispherical shell-shaped half shell was molded from the above-mentioned cover composition,
The core was wrapped in a single piece, press-molded in a mold for a golf ball, and then paint was applied to the surface to produce a thread-wound golf ball having an outer diameter of 42.7 mm. The golf balls of Examples 1 to 7 and Comparative Example 2 were press molded at 150 ° C. for 5 minutes, and the golf balls of Comparative Example 1 and Comparative Examples 3 to 6 were press molded at 90 ° C. for 10 minutes and then vulcanized. Accelerator Nox Cellar PPD [trade name,
Ouchi Shinko Chemical Industry Co., Ltd., pentamethylene dithiocarbamate piperidine] in a 5% by weight aqueous dispersion of 35 ℃
It was dipped for 1 day and vulcanized.

The weight, compression, rebound coefficient and flight distance of the obtained golf ball were measured, and the cut resistance, shot feeling and controllability were examined. The compression is measured by the PGA method. The coefficient of repulsion was measured by R & A initial velocity measuring machine to the ball 198.4.
The ball velocity when a metal cylinder of g was made to collide at a velocity of 45 m / s was measured and calculated from the ball velocity, and the temperature at the time of measuring the ball velocity was 23 ° C. The flight distance was measured by attaching a Wood No. 1 club to a swing robot manufactured by Trutemper and hitting the ball at a head speed of 45 m / s. And cut resistance is attached to the swing robot manufactured by Trutemper Co., Ltd. with a pitching wedge,
The state of occurrence of cut scratches was examined by hitting the top at a speed of 0 m / s, and the evaluation result is when the state of cut damage of the golf ball of Comparative Example 1 using a normal balata cover is 100. It shows with the index of. Therefore,
The smaller this index, the less likely it is to scratch and the better the cut resistance.

Further, the shot feeling and controllability were evaluated by an actual hit test with a No. 1 wood club by 10 top professionals, and the results were classified into the following two types. The same symbols are used in the display of the evaluation results in the table, which means that 8 or more out of 10 people gave the same evaluation.

Evaluation Criteria: ◯: Good shot feeling and controllability equivalent to balata cover. X: The shot feeling is too hard and poor, and the controllability is insufficient. In particular, the stopping feeling on the approach shot is poor and the variation is large.

In Tables 4 and 5, the golf balls of Examples 1 to 7 and Comparative Examples 1 to 6 were measured for weight, compression, rebound coefficient, flight distance, cut resistance, shot feeling and controllability. The type of cover composition used in the production is also shown. However, the composition for a cover is shown by each preparation example number and comparative preparation example number.

[0054]

[Table 2]

[0055]

[Table 3]

* 1: Zinc neutralized sulfonic acid added transpo
Li butadiene below a commercially available trans-polybutadiene by the process TP049 [trade name, Asahi Chemical Industry Co., Ltd.] a sulfonic acid group was added to the obtained by neutralizing with zinc ion sulfonic acid group addition amount = about 1 A modified product of trans polybutadiene having a neutralization degree of 100% by zinc ion of 0.0 mol%.

Production method: Acetic anhydride and concentrated sulfuric acid were added to an n-hexane solution of TP-049 (trade name), and the mixture was stirred at room temperature for 30 minutes. To this, a water-methanol solution of zinc acetate is added to neutralize. After that, the anti-aging agent Irganox 10
10 (trade name, manufactured by Ciba Geigy) was added at 0.5% by weight of TP049 (trade name), and the neutralized solution was poured into boiling water to remove the solvent, followed by washing with water and drying. The acetic anhydride and concentrated sulfuric acid are added as a 10% solution of hexane / isoproalcohol = 100/15. The ratio of each reaction component is 2.0 g of sulfuric acid, 1.0 g of acetic anhydride, and 3.5 g of zinc acetate with respect to 100 g of TP049 (trade name).
A modified product of trans-polybutadiene having about 1.0 mol% of sulfonic acid groups neutralized with 0% zinc ion was obtained. In Table 2, this is indicated as zinc-neutralized sulfonic acid-added trans polybutadiene as described above because of space considerations.

* 2: Zinc neutralized sulfonic acid-added transpo
Ributadiene trans Polybutadiene sulfonic acid group addition amount% about 6.
Modified product with 0 mol% and 100% zinc ion neutralization degree. Table 2
Then, this modified product of trans-polybutadiene was designated as zinc-neutralized sulfonic acid-added trans-polybutadiene as described above.

The production method is the same as in the case of * 1 above, using the same transpolybutadiene [TP049 (trade name) manufactured by Asahi Kasei Kogyo Co., Ltd.]. However,
In order to make the added amount of sulfonic acid groups (addition concentration of sulfonic acid groups neutralized with zinc ions) about 6.0 mol%, TP0
The addition ratio of acid and zinc acetate to 100 g of 49 (trade name) was changed as follows.

TP049 (trade name) / sulfuric acid / acetic anhydride /
Zinc acetate = 100 g / 1.2 g / 0.6 g / 2.4 g

* 3: Zinc neutralized sulfonic acid-added transpo
A polyisoprene commercial trans polyisoprene TP301 [trade name, Ltd. Kuraray] adding a sulfonic acid group in, be sulfonic acid group addition amount obtained by neutralizing with zinc ion = about 1.2
Modified product with mol% and zinc ion neutralization degree = 100%. In Table 2, this modified product of trans polyisoprene is indicated as zinc-neutralized sulfonic acid-added trans polyisoprene as described above.

The manufacturing method is the same as the above * 1. However, trans polyisoprene was used in place of trans polybutadiene, and the proportion of each reaction component was as follows.

TP301 (trade name) / sulfuric acid / acetic anhydride /
Zinc acetate = 100g / 2.0g / 1.0g / 3.5g

* 4: Zinc-neutralized sulfonic acid-added transpo
Bestenemer 8 which is a commercially available trans-polyoctenemer
012 (trade name, manufactured by Huls) was added with a sulfonic acid group and neutralized with zinc ions to obtain a sulfonic acid group addition amount of about 2.0 mol% and a zinc ion neutralization degree of 100%. Quality product. In Table 2, this modified product of trans-polyoctenemer is designated as zinc-neutralized sulfonic acid-added trans-polyoctenemer as described above.

The manufacturing method is the same as the above * 1. However, instead of trans polybutadiene, trans polyoctenemer was used, and the ratio of each reaction component was as follows.

Bestenemer 8012 (trade name) / sulfuric acid /
Acetic anhydride / zinc acetate = 100 g / 2.0 g / 1.0 g /
3.5 g

* 5: TP301 trade name, Kuraray Co., trans polyisoprene, characteristic values are listed in Table 1.

* 6: TP049 trade name, Asahi Chemical Industry Co., Ltd., trans polybutadiene, characteristic values are shown in Table 1.

* 7: Bestenemer 8012 trade name, manufactured by Huls, transpolyoctenemer , property values are listed in Table 1.

* 8: Nipol 2007J trade name, Nippon Zeon Co., Ltd., high styrene resin (85% by weight of styrene, 15% by weight of butadiene)

* 9: Himilan # 1605 trade name, manufactured by Mitsui DuPont Polychemical Co., Ltd., sodium ion-neutralized ethylene-methacrylic acid copolymer type ionomer resin, MI (melt index) = 2.8

* 10: Himilan # 1706 trade name, manufactured by Mitsui DuPont Polychemical Co., Ltd., zinc ion neutralized ethylene-methacrylic acid copolymer type ionomer resin, MI = 0.8

[0073]

[Table 4]

[0074]

[Table 5]

As is clear from the results shown in Tables 4 and 5, the golf balls of Examples 1 to 7 have the same excellent shot feeling and controllability as those of Comparative Example 1 using the balata cover, and the resilience. The performance, flight distance, and cut resistance were improved to almost the same performance as the golf ball of Comparative Example 2 using the hard ionomer resin cover.

As described above, the golf ball of the present invention has the problems of the conventional cover, that is, the drawbacks of the balata cover ball, such as the resilience performance, the short flight distance and the poor cut resistance, and the hard ionomer resin cover ball. It can be said that the golf ball has a nearly ideal cover that solves the drawbacks of hitting feeling and poor controllability at the same time.

On the other hand, the golf ball of Comparative Example 2 has poor shot feeling and controllability, and the golf balls of Comparative Example 1 and Comparative Examples 3 to 6 have good shot feeling and controllability, but a coefficient of restitution. The flight distance was short and the cut resistance was poor.

[0078]

As described above, according to the present invention,
Provided is a golf ball having an excellent shot feeling and controllability equivalent to those of a balata cover, high resilience performance, a long flight distance, and excellent cut resistance.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing an example of a golf ball according to the present invention.

[Explanation of symbols]

 1 core 1a center 1b thread rubber 2 cover

Claims (3)

[Claims] 1. A golf ball having a core and a cover that covers the core, wherein the main component of the base polymer of the cover is trans-polybutadiene or trans-polyisoprene to which a sulfonic acid group neutralized with a metal ion is added, or A golf ball comprising a trans polyoctenemer or a mixture thereof. 2. The added sulfonic acid group has a zinc ion of 1
It is 100% neutralized, and the addition amount of sulfonic acid groups to trans polybutadiene or trans polyisoprene or trans polyoctenemer or a mixture thereof is 0.
The golf ball according to claim 1, wherein the content is 2 to 3 mol%. 3. The golf ball according to claim 1, wherein the trans 1,4-bond content of trans polybutadiene, trans polyisoprene, or trans polyoctenemer is 60% or more.