JP5623695B2 - Golf ball - Google Patents

Description

  The present invention relates to a golf ball excellent in durability and scratch resistance.

  In recent years, using a biodegradable resin as a high molecular weight material constituting a golf ball has been studied from the viewpoint of environmental conservation or from the viewpoint that a golfer can practice without collecting a large number of lost balls. For example, Patent Document 1 includes a one-piece golf ball or a single layer or a plurality of layers covering the core for the purpose of providing a golf ball with a reduced load on the natural environment. In such a golf ball, a golf ball in which any one of its constituent members is formed of a biodegradable material is disclosed.

Patent Document 2 discloses a golf ball that is substantially spherical and substantially biodegradable for the purpose of providing a golf ball in which a golfer can repeatedly practice a golf swing without collecting a large number of golf balls after practice in a narrow place. An outer shell defining an internal cavity and a substantially biodegradable load absorbing member disposed in the internal cavity, the load absorbing member having performance characteristics of a golf ball. A golf ball is disclosed which has a function to influence and make the maximum flight distance of the golf ball less than about 75 yards.
JP 2006-247224 A US Published Patent No. 2004/0209701

  As described above, biodegradable materials have been studied as materials for golf balls. However, golf balls having a cover using a biodegradable material alone as a resin component are very hard and brittle. As a result, the durability and scuff resistance of the golf ball decreases.

  The inventor previously described a golf ball having a core and a cover covering the core, wherein at least one of the core and the cover is a polyester resin having a petroleum-free material as a constituent component as a resin component. It has applied for a golf ball characterized by containing. However, a golf ball having a cover using a polyester resin alone as a constituent component of a petroleum-free material as a resin component also tends to be hard and brittle.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a golf ball using a petroleum-free material and having excellent durability and scratch resistance.

  The golf ball of the present invention that has solved the above problems is a golf ball having a core and a cover that covers the core, wherein the cover is (a) a dicarboxylic acid as a resin component (a-1) (A-2) having a diol and / or hydroxycarboxylic acid as a constituent component, wherein at least one of (a-1) dicarboxylic acid, (a-2) diol and / or hydroxycarboxylic acid is deoiled It is characterized by being formed from a cover composition containing a non-petroleum polyester resin, which is a base material, and (B) acicular and / or fibrous filler. By including a resin component containing a non-petroleum-based polyester resin and a needle-like and / or fibrous filler in the cover composition, the durability and scratch resistance of the golf ball as a whole can be improved. .

  The needle-like and / or fibrous filler (B) contained in the cover composition preferably has an average length of 1 to 2000 μm and an average aspect ratio of 10 to 100. Moreover, it is preferable that content of the said acicular and / or fibrous filler (B) in the said composition for a cover is 1-20 mass parts with respect to 100 mass parts of said resin components (A). .

  The acicular and / or fibrous filler (B) is preferably, for example, kenaf fiber as the fibrous filler, and examples of the acicular filler include potassium titanate whisker, graphite whisker, alumina whisker, and silicon carbide. Whisker, silicon nitride whisker, mullite whisker, magnesia whisker, magnesium borate whisker, zinc oxide whisker, and titanium boride whisker are preferred.

  According to the present invention, a golf ball using a petroleum-free material and having excellent durability and scratch resistance can be obtained.

  The golf ball of the present invention is a golf ball having a core and a cover covering the core, the cover comprising (a) a resin component (a-1) dicarboxylic acid, (a-2) diol, and And / or hydroxycarboxylic acid as a constituent component, wherein (a-1) dicarboxylic acid, (a-2) at least one of diol and / or hydroxycarboxylic acid is a depetroleum-based polyester It is formed from the composition for a cover containing resin and the (B) acicular and / or fibrous filler.

  First, a polyester resin (hereinafter, sometimes simply referred to as “de-petroleum-based polyester resin”) having a de-petroleum-based material used as the (A) resin component of the cover composition as a constituent component will be described.

  The petroleum-removed polyester resin has (a-1) dicarboxylic acid, (a-2) diol and / or hydroxycarboxylic acid as a constituent component, and (a-1) dicarboxylic acid, (a-2) ) It is sufficient that at least one of the diol and / or hydroxycarboxylic acid is a non-petroleum-based material, for example, a copolymer polyester resin having a dicarboxylic acid and a diol as constituent components, and at least of the dicarboxylic acid and the diol Polyester resin comprising one of the petroleum-free materials; a copolymer polyester resin comprising dicarboxylic acid, diol, and hydroxycarboxylic acid as constituents, and at least one of dicarboxylic acid, diol, and hydroxycarboxylic acid Polyester resin with a petroleum-free material; polyhydroxycarboxylic acid bromine And a polyester resin having at least one of dicarboxylic acid, diol, and hydroxycarboxylic acid as a de-petroleum-based material. .

  Here, the non-petroleum-based material is not a material obtained by refining, catalytic reforming, or catalytic cracking of petroleum, but a material derived from plants such as corn, potatoes, beets and sugar cane. For example, it can be obtained by processing corn, potatoes, beets, sugar cane, etc. into starch or sugar (such as cellulose) and fermenting the obtained starch with a microorganism. Moreover, it can also be made by a known fermentation method and / or chemical conversion method using vegetable oils and animal fats.

  Such plant-derived non-petroleum-based materials can absorb and fix carbon dioxide in the atmosphere. In addition, carbon dioxide generated when incinerated plant-derived non-petroleum-based materials originally existed in the atmosphere, so the amount of carbon dioxide in the atmosphere is increased as when petroleum-based materials are incinerated. There is nothing. Therefore, by using a petroleum-free polyester resin as the resin component of the cover composition, an increase in the amount of carbon dioxide in the atmosphere can be suppressed, which can contribute to the prevention of global warming.

  The dicarboxylic acid (a-1) is not particularly limited as long as it is an organic compound having two carboxyl groups in the molecule. For example, succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic anhydride Acid, fumaric acid, 1,3-cyclopentanedicarboxylic acid, terephthalic acid, isophthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid Examples include acids and dicarboxylic acids such as biphenyldicarboxylic acid, and those exemplified may be used alone or as a mixture of two or more. Among these, it is preferable to use succinic acid, adipic acid, fumaric acid, malic acid, pyruvic acid, etc. as a petroleum-removing material.

  The diol (a-2) is not particularly limited as long as it is an organic compound having two hydroxyl groups in the molecule. For example, ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, 1, Examples include 4-cyclohexanediol and diols such as bisphenol A, and those exemplified may be used alone or as a mixture of two or more. Among these, it is preferable to use 1,4-butanediol, 1,3-propanediol, ethylene glycol, and the like as the petroleum-free material.

  The hydroxycarboxylic acid is not particularly limited as long as it is an organic compound having one hydroxyl group and one carboxyl group in the molecule. For example, lactic acid, hydroxyacetic acid (glycolic acid), hydroacrylic acid, hydroxybutyric acid , Hydroxyvaleric acid, hydroxycyclohexanecarboxylic acid, salicylic acid, hydroxybenzoic acid, hydroxytoluic acid and the like, and those exemplified may be used alone or as a mixture of two or more.

  Among these, particularly preferred is polybutylene succinate using butanediol as the diol component, succinic acid as the dicarboxylic acid component, butanediol as the diol component, and succinic acid and adipic acid as the dicarboxylic acid component. The polybutylene succinate adipate used can be mentioned. In this case, the blending ratio of succinic acid and adipic acid is preferably 60/40 to 95/5, more preferably 70/30 to 90/10, and even more preferably 75/25 to 85/15 in terms of mass ratio. In general, a polymer material having high rigidity also has high hardness. Therefore, when used as a resin component constituting the cover, the obtained cover becomes brittle and the durability is lowered. However, since the polybutylene succinate and the polybutylene succinate adipate have a high hardness and a low hardness, the durability can be improved when used as a resin component constituting the cover. The said petroleum-removed polyester resin can be synthesized by a known method for synthesizing a polyester resin.

  The polybutylene succinate or polybutylene succinate adipate has, for example, a weight average molecular weight of 50,000 to 200,000 (preferably 70,000 to 80,000) and a glass transition temperature of −40 ° C. to −10 ° C. (Preferably −30 ° C. to −20 ° C.) and MFR (190 ° C., 2.16 kg load) of 2 g / 10 min to 30 g / 10 min (preferably 5 g / 10 min to 20 g / 10 min) are preferably used. it can.

  The slab hardness of the petroleum-free polyester resin is preferably 70 or less, more preferably 68 or less, and even more preferably 65 or less in Shore D hardness. If the slab hardness of the depetroleum polyester resin exceeds 70 in Shore D hardness, the resulting cover may be too hard and the durability may be lowered. In addition, the slab hardness of the petroleum-free polyester resin is preferably 30 or more, more preferably 35 or more, and even more preferably 40 or more in Shore D hardness. This is because if the slab hardness of the petroleum-free polyester resin is less than 30, the tackiness becomes strong and the resilience is lowered. The slab hardness of the petroleum-free polyester resin can be set to the above range by appropriately selecting, for example, the type of copolymerization component, the content ratio, the molecular weight of the resulting polyester resin, and the like. For example, a copolymerized polyester resin of polylactic acid, butanediol, and succinic acid has a lower hardness than the case where polylactic acid is mixed with polybutylene succinate, and therefore has excellent durability.

  Moreover, in this invention, it is preferable that the said composition for a cover contains the said petroleum-removed polyester resin and other petroleum-type thermoplastic resin as (A) resin component. The durability of the cover is further improved by using the above-mentioned petroleum-removed polyester and another thermoplastic resin as the resin component (A) of the cover composition, as compared with the case of using only the petroleum-removed polyester. Can do. Here, the petroleum-based thermoplastic resin is a thermoplastic resin that does not have a petroleum-free material as a constituent component and is manufactured from a raw material obtained by refining, catalytic reforming, catalytic cracking, or the like.

  Examples of the petroleum thermoplastic resins include ionomer resins, polyurethane resins, polystyrene resins, polyamide resins, and polyester resins. Examples of the ionomer resin include those obtained by neutralizing at least part of carboxyl groups in a copolymer of ethylene and an α, β-unsaturated carboxylic acid having 3 to 8 carbon atoms with a metal ion, ethylene and carbon number. What neutralized at least one part of the carboxyl group in the terpolymer of 3-8 alpha, beta-unsaturated carboxylic acid and alpha, beta-unsaturated carboxylic acid ester with a metal ion, or these Can be mentioned.

  Specific examples of the ionomer resin are illustrated by trade names, such as “Himilan (registered trademark)” (for example, Himilan 1555 (Na), Himilan 1557 (Zn), Himilan, which is commercially available from Mitsui DuPont Polychemical Co., Ltd.). 1605 (Na), Himilan 1706 (Zn), Himilan 1707 (Na), Himilan AM7311 (Mg) and the like. Examples of the terpolymer ionomer resin include “Himilan 1856 (Na), Himilan 1855 (Zn) and the like. ) ".

  Further, ionomer resins commercially available from DuPont include “Surlyn (registered trademark)” (for example, Surlyn 8945 (Na), Surlyn 9945 (Zn), Surlyn 8140 (Na), Surlyn 8150 (Na), Surlyn 9120 (Zn), Surlyn 9150 (Zn), Surlyn 6910 (Mg), Surlyn 6120 (Mg), Surlyn 7930 (Li), Surlyn 7940 (Li), Surlyn AD8546 (Li) and the like, and terpolymers Examples of the ionomer resin include Surlyn 8120 (Na), Surlyn 8320 (Na), Surlyn 9320 (Zn), Surlyn 6320 (Mg)).

  Examples of ionomer resins commercially available from ExxonMobil Chemical Co., Ltd. include “Iotek (registered trademark)” (for example, Iotech 8000 (Na), Iotech 8030 (Na), Iotech 7010 (Zn), Iotech 7030 ( Zn) and the like, and examples of the ternary copolymer ionomer resin include Iotech 7510 (Zn) and Iotech 7520 (Zn)). As the ionomer resin, those exemplified may be used singly or as a mixture of two or more. Na, Zn, K, Li, Mg, etc. described in parentheses after the trade name of the ionomer resin indicate the metal species of these neutralized metal ions.

  Specific examples of other petroleum-based thermoplastic resins include, for example, a thermoplastic polyamide resin marketed by Arkema Co., Ltd. under the trade name “Pebax (registered trademark)” (for example, “Pebax 2533”), Toray DuPont ( A thermoplastic polyester resin commercially available under the trade name “Hytrel (registered trademark)” (for example, “Hytrel 3548” and “Hytrel 4047”) from Mitsubishi Chemical Corporation, and the trade name “Lavalon (registered trademark)” from Mitsubishi Chemical Corporation. And thermoplastic polyurethane resins commercially available from BASF Polyurethane Elastomers under the trade name “Elastolan (registered trademark)” (for example, “Elastolan ET880”). it can. Among these, the cover is at least one petroleum-based heat selected from the group consisting of the petroleum-removed polyester resin, ionomer resin, polyurethane resin, polystyrene resin, polyester resin, and polyamide resin as a resin component. It is a preferable aspect to contain a mixture with a plastic resin, and it is a more preferable aspect to contain the mixture of the said petroleum-free polyester resin and ionomer resin.

  30 mass% or more is preferable, as for the content rate of the said petroleum-free polyester resin in the said mixture, 40 mass% or more is more preferable, and 45 mass% or more is further more preferable. By setting the content of the petroleum-free polyester resin to 30% by mass or more, the durability improvement effect becomes remarkable. On the other hand, the upper limit of the content of the petroleum-free polyester resin in the mixture is not particularly limited, but is preferably 100% by mass, more preferably 90% by mass, and still more preferably 80% by mass.

  In a preferred embodiment of the present invention, the cover composition further comprises at least one petroleum selected from the group consisting of the petroleum-removed polyester resin and ionomer resin, polyurethane resin, polystyrene resin, polyester resin, and polyamide resin. A compatibilizer with a thermoplastic resin. Simply mixing the above-described petroleum-free polyester resin and petroleum-based thermoplastic resin may cause phase separation depending on the type of petroleum-based thermoplastic resin, and the appearance of the resulting golf ball may be reduced. is there.

  The compatibilizing agent may be any as long as it can enhance the compatibility between the petroleum-removed polyester resin and the other petroleum-based thermoplastic resin, and may be appropriately selected according to the type of the petroleum-based thermoplastic resin. it can. For example, a thermoplastic elastomer such as a polyolefin-based elastomer, a polyester-based elastomer, a polyurethane-based elastomer, a polyamide-based elastomer, or a polystyrene-based elastomer is modified with a polar functional group.

  Examples of the polar functional group include an epoxy group typified by a carboxyl group and a glycidyl group, a hydroxyl group, and a sulfonic acid group. By using an elastomer modified with a polar functional group, it is possible to enhance the compatibility of the petroleum-free polyester resin with other petroleum-based thermoplastic resins.

  Specific examples of the compatibilizer include, for example, maleic acid-modified styrene-ethylene-butylene-styrene block polymer (SEBS), maleic acid-modified styrene-ethylene-butylene-olefin crystal block polymer (SEBC), maleic acid-modified polyethylene ( PE), methyl methacrylate-glycidyl methacrylate copolymer, ethylene-glycidyl methacrylate copolymer, ethylene-methyl methacrylate-glycidyl methacrylate copolymer, maleic acid modified polypropylene (PP), maleic acid modified ethylene-vinyl acetate copolymer ( EVA) and maleic acid-modified ethylene-propylene-diene rubber (EPDM).

  The content of the compatibilizer in the cover composition is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and still more preferably 3 parts by mass or more with respect to 100 parts by mass of the resin component (A). Moreover, 25 mass parts or less are preferable, 20 mass parts or less are more preferable, and 15 mass parts or less are more preferable. By setting the content of the compatibilizer to 1 part by mass or more, the compatibility between the de-petroleum polyester resin and other petroleum-based thermoplastic resins can be improved, and by setting it to 25 parts by mass or less. The compatibility between the de-petroleum polyester resin and other petroleum-based thermoplastic resins can be improved.

  Next, the (B) acicular or fibrous filler used in the present invention will be described. The needle-like or fibrous filler used in the present invention is not particularly limited as long as it is a filler having a needle-like or fibrous shape, and generally commercially available needle-like fillers and fibrous fillers can be used. it can.

  Examples of the acicular filler include inorganic substances such as potassium titanate whiskers, graphite whiskers, alumina whiskers, silicon carbide whiskers, silicon nitride whiskers, mullite whiskers, magnesia whiskers, magnesium borate whiskers, zinc oxide whiskers, and titanium boride whiskers. Whisker and a plurality of needle-shaped fillers are bonded to each other at one end, and a three-dimensional metal oxide having a three-dimensional shape with the other end positioned in a different direction (for example, Matsushita Electric Industrial Co., Ltd. Manufactured by Panatetra (registered trademark)). These needle-like fillers may be used alone or in combination of two or more.

Examples of the fibrous filler include natural fibers such as kenaf, cotton, flax, wool, silk, feathers, and asbestos; synthetic fibers such as nylon fibers, vinylon fibers, acrylic fibers, polyester fibers, polyolefin fibers, and polyurethane fibers; glass Inorganic fibers such as fiber, carbon fiber, alumina fiber, potassium titanate fiber, basic magnesium sulfate fiber, and calcium carbonate fiber; such as wollastonite (CaO · SiO ₂ ) and fibrous brucite (Mg (OH) ₂ ) Natural mineral fibers; metal fibers can be mentioned. These fibrous fillers may be used alone or in combination of two or more. Moreover, it is also possible to use the acicular filler and the fibrous filler in combination.

  The average length of the needle-like and fibrous filler is preferably 1 μm or more, more preferably 2 μm or more, and further preferably 5 μm or more. Further, the average length of the filler is preferably 2,000 μm or less, and more preferably 1,500 μm or less. If the average length of the needle-like and fibrous filler is less than 1 μm, the anchor effect between the cover and the core is reduced, and the durability of the golf ball may not be improved. The average length is 2,000 μm. If it exceeds, there is a risk of causing a poor appearance of the golf ball.

  The average aspect ratio of the needle-like and fibrous filler is preferably 10 or more, and more preferably 15 or more. The average aspect ratio of the filler is preferably 100 or less, and more preferably 50 or less. When the average aspect ratio of the needle-like and fibrous filler is less than 10, the anchor effect between the cover and the core is reduced, and the durability of the golf ball may not be improved. When the average aspect ratio exceeds 100 There is a risk of poor appearance of the golf ball.

  In the present invention, the average filler length means the average length in the longitudinal direction of the needle-like or fibrous filler, and the average aspect ratio means the average length of the needle-like or fibrous filler and the needle-like or fibrous filler. It shall mean the ratio (average length / average diameter) to the average diameter of the fibrous filler. However, in the three-dimensional metal oxide, each whisker constituting the three-dimensional metal oxide is regarded as an individual needle filler, and the average length and the average aspect ratio are obtained.

  In the present invention, the content of the (B) acicular and / or fibrous filler contained in the cover composition is preferably 1 part by mass or more with respect to 100 parts by mass of the (A) resin component, and 3 parts by mass. The above is more preferable, 5 parts by mass or more is further preferable, 20 parts by mass or less is preferable, 18 parts by mass or less is more preferable, and 15 parts by mass or less is further preferable. (B) When the content of the needle-like and / or fibrous filler is less than 1 part by mass, the durability of the obtained cover may be deteriorated. Further, if the content of (B) needle-like and / or fibrous filler exceeds 20 parts by mass, the golf ball may have a poor appearance.

  The golf ball cover composition of the present invention includes the above-mentioned (A) resin component, (B) acicular and / or fibrous filler, compatibilizer, and other pigments such as white pigment (titanium oxide) and blue pigment. Ingredients, specific gravity adjusters such as calcium carbonate and barium sulfate, dispersants, anti-aging agents, ultraviolet absorbers, light stabilizers, fluorescent materials or fluorescent brighteners may be included as long as the performance of the cover is not impaired. Good.

  The content of the white pigment (titanium oxide) is 0.5 parts by mass or more, more preferably 1 part by mass or more, and more preferably 10 parts by mass or less, with respect to 100 parts by mass of the resin component constituting the cover. Is desirably 8 parts by mass or less. By setting the content of the white pigment to 0.5 parts by mass or more, the cover can be concealed. Moreover, it is because durability of the cover obtained may fall when content of a white pigment exceeds 10 mass parts.

  The golf ball cover of the present invention is molded using the cover composition obtained by kneading the above-mentioned (A) resin component, (B) acicular and / or fibrous filler, compatibilizing agent and various additives. It is produced by doing. For kneading the cover composition, a known kneading method can be employed. For example, when kneading using a twin screw extruder, the screw deep groove difference ratio is 1.6 or more, and the screw rotation speed is It is preferable that 200 rpm or more and screw L / D be 30 or more. By setting it as such a specification, it can disperse | distribute in a resin component, maintaining the magnitude | size of the acicular and / or fibrous filler mix | blended.

  Here, the screw deep groove difference ratio is defined by the ratio (OD / ID) between the outer diameter (OD) of the screw and the valley diameter (ID) of the screw in the screw cross section shown in FIG. As the screw deep groove difference ratio value increases, the free volume of the screw increases, so that the (B) charged needle-like and / or fibrous filler is less likely to break, and the average aspect ratio at the time of charging is maintained. However, it can be dispersed in the resin component (A). Further, as shown in FIG. 2, in the twin screw extruder 1, the screw deep groove difference ratio may be 1.6 or more only in the downstream area (shaded area in FIG. 2) from the filler inlet 2 in the extrusion direction. The screw deep groove difference ratio may be less than 1.6 on the upstream side of the insertion port 2. In addition, the arrow A in FIG. 2 has shown the extrusion direction.

  As a method of forming the cover, for example, a method of forming a hollow shell-shaped shell from the cover composition, and covering and compressing the core with a plurality of shells (preferably, forming the cover from the cover composition into a hollow shell-shaped shell). And a method in which a half shell is molded, the core is covered with two half shells and compression molded), and a cover composition is directly injection molded on the core. When forming a cover by directly injection-molding the cover composition onto the core, the upper and lower molds for cover molding have a hemispherical cavity, a hold pin that has pimples and a part of the pimples can be advanced and retracted. It is preferable to use what is also used. The cover can be formed by injection molding by projecting the hold pin, inserting and holding the core, injecting the cover composition, and cooling the cover, for example, 9 MPa to 15 MPa. The cover composition heated to 200 ° C. to 250 ° C. is poured into the mold clamped at a pressure of 0.5 to 5 seconds, cooled for 10 to 60 seconds, and opened.

  Further, when molding the cover, a depression called dimple is usually formed on the surface. Further, it is preferable that the golf ball with the cover formed is taken out of the mold and subjected to surface treatment such as deburring, washing, and sandblasting as necessary. Moreover, a paint layer and a mark can also be formed if desired.

  In the present invention, the thickness of the golf ball cover is preferably 3.0 mm or less, more preferably 2.8 mm or less, and even more preferably 2.5 mm or less. This is because when the thickness is 3.0 mm or less, resilience and feel at impact are improved. Although the minimum of the thickness of a cover is not specifically limited, For example, 0.3 mm is preferable, 0.5 mm is preferable and 1.0 mm is more preferable. This is because if it is less than 0.3 mm, it may be difficult to mold the cover. In addition, the durability and wear resistance of the cover may be reduced.

  The slab hardness of the golf ball cover of the present invention is 40 or more in Shore D hardness, more preferably 45 or more, further preferably 50 or more, 70 or less, more preferably 68 or less. Yes, more preferably 65 or less. By setting the slab hardness of the cover to 40 or more, the rigidity of the obtained cover is increased, and a golf ball having excellent resilience (flying distance) can be obtained. On the other hand, when the slab hardness is 70 or less, the durability is further improved. Here, the slab hardness of the cover is a hardness measured by molding the cover composition into a sheet shape, and is measured by a measurement method described later.

  The golf ball of the present invention is a golf ball having a core and a cover covering the core, the cover comprising (a) a resin component (a-1) dicarboxylic acid, (a-2) diol, and And / or hydroxycarboxylic acid as a constituent component, wherein (a-1) dicarboxylic acid, (a-2) at least one of diol and / or hydroxycarboxylic acid is a depetroleum-based polyester A two-piece golf ball having a core and a cover covering the core is not particularly limited as long as it is formed from a cover composition containing a resin and (B) a needle-like and / or fibrous filler. It can be suitably applied to.

  Next, a preferred embodiment of the core in the golf ball of the present invention will be described.

  Examples of the structure of the core of the golf ball of the present invention include a single-layer core, a core composed of a center and a single-layer intermediate layer covering the center, and a plurality of or multiple intermediate layers covering the center and the center. And a core composed of The core shape is preferably spherical. When the core shape is not spherical, the thickness of the cover is not uniform. As a result, a part in which the cover performance is partially reduced occurs. On the other hand, the shape of the center is generally spherical, but a ridge may be provided so as to divide the surface of the spherical center, for example, the ridge so as to divide the surface of the spherical center equally. May be provided. As an aspect which provides the said protrusion, the aspect which provides a protrusion integrally with a center on the surface of a spherical center, the aspect which provides the intermediate | middle layer of a protrusion on the surface of a spherical center, etc. can be mentioned, for example.

  For example, when the spherical center is regarded as the earth, the ridge is preferably provided along an equator and an arbitrary meridian that equally divides the surface of the spherical center. For example, when the spherical center surface is divided into 8 parts, 90 degrees east longitude, 90 degrees west longitude, and east longitude (west longitude) with reference to the equator, an arbitrary meridian (longitude 0 degrees), and the meridian of such longitude 0 degrees It may be provided along the meridian of 180 degrees. When providing the ridge, the concave portion partitioned by the ridge is filled with a plurality of intermediate layers or a single intermediate layer covering each of the concave portions, and the core shape is made spherical. It is preferable to do so. The cross-sectional shape of the protrusion is not particularly limited, and examples thereof include an arc shape or a substantially arc shape (for example, a shape in which notched portions are provided at portions intersecting or orthogonal to each other).

  For the core or center of the golf ball of the present invention, a conventionally known rubber composition (hereinafter may be simply referred to as “core rubber composition”) may be employed. A rubber composition containing an agent, a co-crosslinking agent and a filler can be molded by hot pressing.

  As the base rubber, natural rubber and / or synthetic rubber can be used. For example, polybutadiene rubber, natural rubber, polyisoprene rubber, styrene polybutadiene rubber, ethylene-propylene-diene rubber (EPDM) and the like can be used. Among these, it is particularly preferable to use a high-cis polybutadiene having a cis bond content advantageous for repulsion of 40% by mass or more, preferably 70% by mass or more, and more preferably 90% by mass or more.

  The said crosslinking initiator is mix | blended in order to bridge | crosslink a base rubber component. As the crosslinking initiator, an organic peroxide can be suitably used. Examples of the organic peroxide include dicumyl peroxide, 1,1-bis (t-butylperoxy) -3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di (t-butyl). Peroxy) organic peroxides such as hexane and di-t-butyl peroxide are mentioned, among which dicumyl peroxide is preferably used. The amount of the crosslinking initiator is 0.3 parts by mass or more, more preferably 0.4 parts by mass or more, and 5 parts by mass or less, more preferably 3 parts by mass or less with respect to 100 parts by mass of the base rubber. It is desirable that If the amount is less than 0.3 parts by mass, the core tends to be too soft and the resilience tends to decrease. If the amount exceeds 5 parts by mass, the core becomes too hard and the feel at impact is reduced.

  As the co-crosslinking agent, an α, β-unsaturated carboxylic acid having 3 to 8 carbon atoms or a metal salt thereof can be used. Examples of the metal constituting the metal salt include zinc, magnesium, calcium, aluminum, and sodium, and zinc is preferably used because resilience increases. Preferable examples of the α, β-unsaturated carboxylic acid or a metal salt thereof include acrylic acid, methacrylic acid, zinc acrylate, and zinc methacrylate.

  The amount of the co-crosslinking agent used is 10 parts by mass or more, more preferably 15 parts by mass or more, still more preferably 20 parts by mass or more, and more preferably 55 parts by mass or less, relative to 100 parts by mass of the base rubber. Is preferably 50 parts by mass or less, more preferably 48 parts by mass or less. When the amount of the co-crosslinking agent used is less than 10 parts by mass, the amount of the crosslinking initiator used must be increased to obtain an appropriate hardness, and the resilience tends to decrease. On the other hand, when the usage-amount of a co-crosslinking agent exceeds 55 mass parts, a core may become hard too much and there exists a possibility that a shot feeling may fall.

  The filler may be anything that is usually blended in the core of a golf ball, such as an inorganic salt (specifically, zinc oxide, barium sulfate, calcium carbonate, etc.), high specific gravity metal powder (eg, tungsten powder, molybdenum). Powders) and mixtures thereof. The blending amount of the filler is 0.5 parts by mass or more, preferably 1 part by mass or more, and 30 parts by mass or less, preferably 20 parts by mass or less with respect to 100 parts by mass of the base rubber. desirable. If the amount is less than 0.5 parts by mass, it is difficult to adjust the specific gravity and an appropriate mass cannot be obtained. If the amount exceeds 30 parts by mass, the rubber fraction of the entire core is reduced and the resilience is lowered.

  In addition to the base rubber, the crosslinking initiator, the co-crosslinking agent, and the filler, an organic sulfur compound, an antiaging agent, a peptizer, and the like can be appropriately added to the core rubber composition.

  As the organic sulfur compound, diphenyl disulfides can be preferably used. Examples of the diphenyl disulfides include diphenyl disulfide; bis (4-chlorophenyl) disulfide, bis (3-chlorophenyl) disulfide, bis (4-bromophenyl) disulfide, bis (3-bromophenyl) disulfide, bis (4- Mono-substituted products such as fluorophenyl) disulfide, bis (4-iodophenyl) disulfide, bis (4-cyanophenyl) disulfide; bis (2,5-dichlorophenyl) disulfide, bis (3,5-dichlorophenyl) disulfide, bis ( 2,6-dichlorophenyl) disulfide, bis (2,5-dibromophenyl) disulfide, bis (3,5-dibromophenyl) disulfide, bis (2-chloro-5-bromophenyl) disulfide, bis (2-cyano Disubstituted compounds such as 5-bromophenyl) disulfide; trisubstituted compounds such as bis (2,4,6-trichlorophenyl) disulfide and bis (2-cyano-4-chloro-6-bromophenyl) disulfide; bis (2 , 3,5,6-tetrachlorophenyl) disulfide and the like; bis (2,3,4,5,6-pentachlorophenyl) disulfide, bis (2,3,4,5,6-pentabromophenyl) Examples include penta-substituted products such as disulfide. These diphenyl disulfides can affect the vulcanization state of the rubber vulcanizate and increase the resilience. Among these, it is preferable to use diphenyl disulfide and bis (pentabromophenyl) disulfide from the viewpoint that a highly repulsive golf ball can be obtained. The compounding amount of diphenyl disulfides is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, and preferably 5.0 parts by mass or less, with respect to 100 parts by mass of the base rubber. Preferably it is 3.0 mass parts or less.

  The blending amount of the anti-aging agent is preferably 0.1 parts by mass or more and 1 part by mass or less with respect to 100 parts by mass of the base rubber. Moreover, it is preferable that the compounding quantity of a peptizer is 0.1 to 5 mass parts with respect to 100 mass parts of base rubber.

  The hot-press molding conditions for the core rubber composition may be appropriately set according to the rubber composition, but are usually heated at 130 to 200 ° C. for 10 to 60 minutes, or at 130 to 150 ° C. for 20 to 40 minutes. After heating, it is preferable to perform two-step heating at 160 to 180 ° C. for 5 to 15 minutes.

  When the golf ball of the present invention is a three-piece golf ball or a multi-piece golf ball, as the intermediate layer, for example, a cured product of a rubber composition, a conventionally known ionomer resin, a product name “Arkema Co., Ltd.” Thermoplastic polyamide elastomer commercially available from Pebax (registered trademark) (for example, “Pebucks 2533”), trade names “Hytrel” (for example, “Hytrel 3548”, “Hytrel 4047” from Toray DuPont Co., Ltd.) ")", A thermoplastic polyurethane elastomer commercially available from BASF Japan under the trade name "Elastolan (registered trademark)" (for example, "Elastolan XNY97A"), Mitsubishi Chemical Corporation ) Under the trade name "Lavalon (registered trademark)" Thermoplastic polystyrene elastomers, and the like that. As the ionomer resin, in particular, an ionomer resin obtained by neutralizing at least a part of a carboxyl group in a copolymer of ethylene and an α, β-unsaturated carboxylic acid having 3 to 8 carbon atoms with a metal ion, ethylene and carbon number What neutralized at least one part of the carboxyl group in the terpolymer of 3-8 alpha, beta-unsaturated carboxylic acid and alpha, beta-unsaturated carboxylic acid ester with a metal ion, or these Mention may be made of mixtures.

  Specific examples of the ionomer resin are illustrated by trade names, such as “Himilan (registered trademark)” (for example, Himilan 1555 (Na), Himilan 1557 (Zn), Himilan, which is commercially available from Mitsui DuPont Polychemical Co., Ltd.). 1605 (Na), HiMilan 1706 (Zn), HiMilan 1707 (Na), HiMilan AM7311 (Mg), and the like. Examples of the terpolymer ionomer resins include HiMilan 1856 (Na) and HiMilan 1855 (Zn). ".

  Further, ionomer resins commercially available from DuPont include “Surlyn (registered trademark)” (for example, Surlyn 8945 (Na), Surlyn 9945 (Zn), Surlyn 8140 (Na), Surlyn 8150 (Na), Surlyn 9120 (Zn), Surlyn 9150 (Zn), Surlyn 6910 (Mg), Surlyn 6120 (Mg), Surlyn 7930 (Li), Surlyn 7940 (Li), Surlyn AD8546 (Li) and the like, and terpolymers Examples of the ionomer resin include Surlyn 8120 (Na), Surlyn 8320 (Na), Surlyn 9320 (Zn), Surlyn 6320 (Mg)).

  Examples of ionomer resins commercially available from ExxonMobil Chemical Co., Ltd. include “Iotek (registered trademark)” (for example, Iotech 8000 (Na), Iotech 8030 (Na), Iotech 7010 (Zn), Iotech 7030 ( Zn) and the like, and examples of the ternary copolymer ionomer resin include Iotech 7510 (Zn) and Iotech 7520 (Zn)).

  Note that Na, Zn, K, Li, Mg, and the like described in parentheses after the trade name of the ionomer resin indicate the metal species of these neutralized metal ions. The intermediate layer may further contain a specific gravity adjusting agent such as barium sulfate or tungsten, an anti-aging agent, or a pigment.

  The core used in the golf ball of the present invention has a diameter of 36.8 mm or more, preferably 37.2 mm or more, more preferably 37.6 mm or more, 42.2 mm or less, preferably 41.2 mm or less, more preferably 40. It is preferable to be 8 mm or less. If the core diameter is less than the above lower limit, the cover will be too thick and the rebound will be reduced.On the other hand, if the core diameter exceeds the upper limit, the cover will be too thin. This is because molding becomes difficult.

  When the core has a diameter of 36.8 mm to 42.2 mm, the amount of compressive deformation (the amount by which the core contracts in the compression direction) from when the initial load 98 N is applied to when the final load 1275 N is applied is 2.0 mm or more. More preferably, it is 2.1 mm or more, more preferably 2.3 mm or more, 5.0 mm or less, more preferably 4.7 mm or less, and further preferably 4.5 mm or less. When the amount of compressive deformation is less than 2.0 mm, the feel at impact is hard and worse, and when it exceeds 5.0 mm, the resilience may be lowered.

  It is also a preferred embodiment that the core has a surface hardness greater than the center hardness. By making the surface hardness of the core greater than the center hardness, the launch angle is increased, the spin rate is decreased, and the flight distance is improved. From this viewpoint, the hardness difference between the surface and the center of the core used in the golf ball of the present invention is preferably Shore D hardness of 10 or more, more preferably 15 or more, preferably 40 or less, and more preferably 35 or less. If the difference in hardness is less than the lower limit, it is difficult to achieve a high launch angle and a low spin rate, so the flight distance tends to decrease. Moreover, since the impact force at the time of hitting becomes large, it is difficult to obtain a soft and good shot feeling. On the other hand, when the hardness difference exceeds the above upper limit, the durability tends to decrease.

  The core has a Shore D hardness of 30 or more, preferably 32 or more, more preferably 35 or more, and is preferably 50 or less, preferably 48 or less, more preferably 45 or less. If the central hardness is less than the above lower limit, it tends to be too soft and the resilience tends to decrease, and if it exceeds the above upper limit, it becomes too hard and the feel at impact and the launch angle are reduced, and the spin rate is also high. Increases flight performance. In the present invention, the center hardness of the core means the hardness measured by a spring type hardness tester Shore D type at the center point of the cut surface after cutting the core into two equal parts.

  The core has a Shore D hardness of 45 or more, preferably 50 or more, more preferably 55 or more, and 65 or less, preferably 62 or less, more preferably 60 or less. If the surface hardness is smaller than the above lower limit, it may become too soft, resulting in a decrease in resilience and a launch angle, or a spin amount may increase and flight performance may decrease. If the surface hardness is larger than the above upper limit, it may become too hard and the feel at impact may be reduced. In the present invention, the surface hardness of the core means the hardness measured with the spring type hardness meter Shore D type on the surface of the obtained spherical core. Further, when the core has a multilayer structure, the surface hardness of the core means the hardness of the surface of the outermost layer of the core.

  When the golf ball of the present invention is a thread wound golf ball, a thread wound core may be used as the core. In such a case, as the thread wound core, for example, a thread core composed of a center formed by curing the core rubber composition described above and a thread rubber layer formed by winding the thread rubber around the center in a stretched state is used. do it. The thread rubber wound on the center may be the same as that conventionally used for the thread wound layer of a thread wound golf ball, for example, natural rubber or natural rubber and synthetic polyisoprene with sulfur, You may use what was obtained by vulcanizing the rubber composition which mix | blended the vulcanization adjuvant, the vulcanization accelerator, the anti-aging agent, etc. The thread rubber is stretched about 10 times on the center and wound to form a thread wound core.

  When the golf ball of the present invention has a diameter of 42.67 mm to 43 mm, the amount of compressive deformation (the amount by which the golf ball shrinks in the compression direction) from when the initial load 98N is applied to when the final load 1275N is applied is 2. 0 mm or more, more preferably 2.1 mm or more, further preferably 2.3 mm or more, 3.5 mm or less, more preferably 3.3 mm or less, and further preferably 3.2 mm or less. It is desirable. When the amount of compressive deformation is less than 2.0 mm, the feel at impact is hard and worse, and when it exceeds 3.5 mm, the resilience may be lowered.

  Hereinafter, the present invention will be described in detail by way of examples. However, the present invention is not limited to the following examples, and all modifications and embodiments without departing from the gist of the present invention are not limited thereto. Included in range.

[Evaluation method]
(1) Scratch resistance A commercially available pitching wedge was attached to a swing robot manufactured by True Temper, and the ball was hit once at two locations at a head speed of 36 m / sec. .
Evaluation criteria ○: There is almost no scratch on the surface of the golf ball, or a slight scratch is generated on the surface.
(Triangle | delta): The surface of the golf ball is shaved a little and fuzz has arisen.
X: The surface of the golf ball is considerably shaved and the fuzz is conspicuous.

(2) Durability A metal head # W1 driver was attached to a swing robot manufactured by True Temper, and each golf ball was hit at a head speed of 45 m / sec to collide with a collision plate. This was repeated to measure the number of hits until the golf ball was broken. The durability of each golf ball is determined by golf ball No. The number of hits for 15 golf balls is set to 100, and the number of hits for each golf ball is shown as an index value. The larger the indexed value, the more excellent the golf ball is.

(3) Slab hardness (Shore D hardness)
Using the cover composition, a sheet having a thickness of about 2 mm was produced by hot press molding and stored at 23 ° C. for 2 weeks. An automatic rubber hardness tester P1 type made by Kobunshi Keiki Co., Ltd. equipped with a spring type hardness tester D type as defined in ASTM-D2240 in a state where three or more sheets of this sheet are stacked so as not to affect the measurement substrate. And measured.

(4) Compression deformation (mm)
The amount of deformation in the compression direction (the amount by which the golf ball or core contracts in the compression direction) from when the initial load 98N was applied to the golf ball or core to when the final load 1275N was applied was measured.

[Production of golf balls]
(1) Production of core A rubber center composition having the composition shown in Table 1 was kneaded and heated and pressed at 170 ° C. for 15 minutes in an upper and lower mold having hemispherical cavities to obtain a spherical center.

ＢＲ−７３０：ＪＳＲ（株）製のハイシスポリブタジエン（シス含有率９６％以上）
アクリル酸亜鉛：日本蒸留製のＺＮＤＡ−９０Ｓ
酸化亜鉛：東邦亜鉛製の銀嶺Ｒ
ジクミルパーオキサイド：日本油脂製のパークミルＤ
ジフェニルジスルフィド：住友精化製
硫酸バリウム：堺化学製硫酸バリウムＢＤ

BR-730: High cis polybutadiene (cis content 96% or more) manufactured by JSR Corporation
Zinc acrylate: ZNDA-90S manufactured by Nippon Distilled
Zinc Oxide: Toho Zinc Gin R
Dicumyl peroxide: Park Mill D made by NOF
Diphenyl disulfide: Barium sulfate manufactured by Sumitomo Seika: Barium sulfate BD manufactured by Sakai Chemical

(2) Preparation of cover composition and production of golf ball main body Next, the cover material having the composition shown in Table 2 was mixed by a mesh type co-rotating twin screw extruder to form a pellet cover composition. A product was prepared. The specifications of the meshing type co-rotating twin screw extruder were as follows: screw diameter 32 mm, screw deep groove difference ratio 1.6, screw rotation speed 200 rpm, screw L / D = 44. The blend was heated to 150-230 ° C. at the die position of the extruder. Subsequently, the obtained cover composition was directly injection-molded on the core to produce a cover covering the core. The upper and lower molds for cover molding have hemispherical cavities, are attached with pimples, and also serve as hold pins in which a part of the pimples can advance and retract. The above hold pin is protruded, the core is inserted and held, and then the cover composition heated to 210 ° C. is poured into a mold clamped at a pressure of 80 tons in 0.3 seconds, cooled for 30 seconds and opened. The golf ball was taken out. The surface of the obtained golf ball body is subjected to sand blasting and marking, and then a clear paint is applied, and the paint is dried in an oven at 40 ° C. to obtain a golf ball having a diameter of 42.8 mm and a mass of 45.4 g. Obtained.

  The results of evaluating the scratch resistance, durability, and amount of compressive deformation of the obtained golf ball are shown in Table 2.

脱石油系ポリエステル樹脂：ブタンジオール／コハク酸（脱石油系材料）／アジピン酸共重合ポリエステル樹脂（ポリブチレンサクシネートアジペート）、コハク酸とアジピン酸の配合比率は、コハク酸／アジピン酸＝８０／２０（質量比）
レイシアＨ１００−Ｊ：三井化学社製、ポリ乳酸樹脂
レイシアＭ−１５１Ｓ Ｑ５２：三井化学社製、ポリ乳酸樹脂と脂肪族ジカルボン酸ポリエステル樹脂の混合物
セルグリーン：ダイセル化学工業（株）製、セルグリーンＣＢＳ１７１（ブタンジオール／コハク酸／カプロラクトン）、ただし、すべての成分が、非脱石油系材料からなる。
ハイミラン１６０５：三井デュポンポリケミカル（株）製のナトリウムイオン中和エチレン−メタクリル酸共重合体アイオノマー樹脂
ハイミラン１５５７：三井デュポンポリケミカル（株）製の亜鉛イオン中和エチレン−メタクリル酸共重合体アイオノマー樹脂
ケナフ繊維：（株）ネイチャートラスト社製
金属酸化物：松下電器産業社製、パナテトラ（３次元形状金属酸化物（酸化亜鉛））
ナイロン含有繊維：帝人ファイバー（株）社製、モルフォトーンＢＭ１００Ｃ１０００
ウィスカー：大塚化学社製、ティスモＤ（チタン酸カリウム（Ｋ₂Ｏ・８ＴｉＯ₂））

Non-petroleum-based polyester resin: butanediol / succinic acid (de-petroleum-based material) / adipic acid copolymer polyester resin (polybutylene succinate adipate). 20 (mass ratio)
Lacia H100-J: manufactured by Mitsui Chemicals, polylactic acid resin Lacia M-151S Q52: manufactured by Mitsui Chemicals, a mixture of polylactic acid resin and aliphatic dicarboxylic acid polyester resin Cell Green: manufactured by Daicel Chemical Industries, Ltd., Cell Green CBS171 (Butanediol / succinic acid / caprolactone), but all components are made of non-deoiled materials.
High Milan 1605: Sodium ion neutralized ethylene-methacrylic acid copolymer ionomer resin manufactured by Mitsui DuPont Polychemical Co., Ltd. High Milan 1557: Zinc ion neutralized ethylene-methacrylic acid copolymer ionomer resin manufactured by Mitsui DuPont Polychemical Co., Ltd. Kenaf fiber: Metal oxide manufactured by Nature Trust Co., Ltd .: Matsushita Electric Industrial Co., Ltd., Panatetra (three-dimensional shape metal oxide (zinc oxide))
Nylon-containing fiber: manufactured by Teijin Fibers Ltd., Morphone BM100C1000
Whisker: Tismo D (potassium titanate (K ₂ O · 8TiO ₂ )) manufactured by Otsuka Chemical Co., Ltd.

  Golf ball no. 1-No. 10 is a golf ball having a core and a cover covering the core, the cover comprising (A) a resin component (a-1) dicarboxylic acid, (a-2) diol and / or hydroxycarbon An acid as a constituent component, wherein (a-1) at least one of dicarboxylic acid, (a-2) diol and / or hydroxycarboxylic acid is a depetroleum polyester resin which is a depetroleum material; B) It is a case where it is formed from a composition for a cover containing acicular and / or fibrous fillers. These golf balls No. Nos. 1 to 10 are golf ball Nos. Using ionomer resins that have been used for conventional covers. It can be seen that the scratch resistance and durability are improved as compared with 15. Golf ball No. In No. 4, since the filler content was 20 parts by mass or more with respect to 100 parts by mass of the resin component, the improvement in durability was small. Golf ball no. No. 10 had a small improvement in durability since the average aspect ratio of the filler was less than 10.

  Golf ball no. 11 is a case where (B) needle-like and / or fibrous filler is not contained, but golf ball No. 11 using ionomer resin which has been conventionally used. It can be seen that although the durability is improved as compared to 15, the scratch resistance is very low. Golf ball no. No. 12 is a case where polycaprolactone which does not use a petroleum-free material is used alone as a resin component of the cover, but a golf ball No. 12 using an ionomer resin which has been conventionally used. The durability was lower than 15. Golf ball no. 13 is a case where a mixture of a polylactic acid resin and an aliphatic dicarboxylic acid polyester resin was used as the resin component of the cover, but a practical level of durability could not be obtained. Golf ball no. 14 is a case where a polylactic acid resin is used as the resin component of the cover. Similar to 13, it was not possible to obtain a practical level of durability.

  According to the present invention, the durability and scratch resistance of a golf ball can be improved.

It is a schematic sectional drawing of the screw of a twin-screw extruder. It is a schematic side view of a twin screw extruder.

Explanation of symbols

1 Twin screw extruder 2 Filler inlet 3 Resin inlet

Claims (4)

A golf ball having a core and a cover covering the core,
The cover contains (A) a resin component, (B) a fibrous filler, and a compatibilizing agent,
The (A) resin component has (a-1) dicarboxylic acid, (a-2) diol and / or hydroxycarboxylic acid as a constituent component, and (a-1) dicarboxylic acid, (a-2) ) At least one of the diol and / or hydroxycarboxylic acid contains a depetroleum polyester resin that is a depetroleum material obtained by fermenting starch with a microorganism, and a petroleum thermoplastic resin;
The petroleum-based thermoplastic resin is an ionomer resin, polyurethane resin, polystyrene resin, polyamide resin or polyester resin,
The compatibilizer is maleic acid-modified styrene-ethylene-butylene-styrene block polymer, maleic acid-modified styrene-ethylene-butylene-olefin crystal block polymer, maleic acid-modified polyethylene, methyl methacrylate-glycidyl methacrylate copolymer, ethylene-glycidyl. A methacrylate copolymer, an ethylene-methyl methacrylate-glycidyl methacrylate copolymer, a maleic acid-modified polypropylene, a maleic acid-modified ethylene-vinyl acetate copolymer, or a maleic acid-modified ethylene-propylene-diene rubber;
The golf ball characterized in that the (B) fibrous filler is at least one kind selected from the group consisting of kenaf, cotton, flax, wool, silk, feathers and asbestos . Before average length of Ki繊維状filler (B) The golf ball according to claim 1 which is 1Myuemu～2000myuemu. Before an average aspect ratio of Ki繊維状filler (B) The golf ball according to claim 1 or 2 which is 10 to 100. The content of pre Ki繊維状filler (B) in the cover composition, any one of claims 1 to 3 wherein a resin component (A) 1 part by weight to 20 parts by weight per 100 parts by weight The golf ball according to one item.

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