JP2008073567A - Golf ball - Google Patents

Abstract

(A) Polybutadiene having 60% or more of cis 1,4 bonds, having a Mooney viscosity (ML _{1 + 4} (100 ° C.)) of ML, and a 5 mass% toluene solution at 25 ° C. Polybutadiene synthesized using a rare earth element-based catalyst satisfying the relationship of 20 × ML-200 ≧ η ≧ 20 × ML-540 when ML is η (mPa · s) and ML is 40 or more and 80 or less. 10 to 90% by mass of a base rubber, an unsaturated carboxylic acid and / or a metal salt thereof, an organic peroxide, and an anti-aging agent, and the anti-aging agent is added to 100% by mass of the base rubber. Provided is a golf ball comprising as a component a thermoformed product of a rubber composition blended in an amount of 0.2 parts by mass or less with respect to parts.
[Effect] The golf ball of the present invention is excellent in resilience.
[Selection figure] None

Description

  The present invention relates to a golf ball having a molded article using polybutadiene having a high linearity (linearity) of butadiene rubber molecules and excellent in resilience.

  Conventionally, in order to impart excellent resilience to golf balls, various improvements have been made in the composition of polybutadiene used as a base rubber.

  For example, JP-A-62-89750 (Patent Document 1) discloses a Mooney viscosity synthesized with a polybutadiene having a Mooney viscosity of 70 to 100 synthesized using a Ni, Co catalyst as a base rubber and a lanthanum catalyst. A rubber composition for a solid golf ball has been proposed which is blended with 30 to 90 polybutadiene or a polybutadiene having a Mooney viscosity of 20 to 50 synthesized using a Ni, Co catalyst.

  However, the above proposal requires further improvement in resilience.

  JP-A-2-268778 (Patent Document 2) is formed by blending a polybutadiene having a Mooney viscosity of less than 50 synthesized with a Group VIII catalyst and a polybutadiene having a Mooney viscosity of less than 50 synthesized using a lanthanide catalyst. However, the resilience of the obtained golf ball is inferior.

  Further, JP-A-11-70187 (Patent Document 3) discloses a multi-piece solid golf ball in which an intermediate layer is formed of polybutadiene having a low Mooney viscosity, and JP-A-11-319148 (Patent Document 4). Solid golf ball formed of a rubber composition comprising a polybutadiene having a Mooney viscosity of 50 to 69 synthesized using Ni, Co catalyst and a polybutadiene having a Mooney viscosity of 20 to 90 synthesized using a lanthanoid catalyst JP-A-11-164912 (Patent Document 5) discloses a rubber composition having a 1,2 vinyl bond of 2.0% or less and a ratio Mw / Mn of weight average molecular weight to number average molecular weight of 3.5 or less. A solid golf ball formed in the Japanese Patent Application Laid-Open No. 63-275356 (Patent Document 6) contains polybutadiene having a high Mooney viscosity. The golf ball formed with the rubber composition, Japanese Patent Application Laid-Open No. 3-151985 (Patent Document 7) is formed with a rubber composition formed by blending a polybutadiene having a high number average molecular weight and a polybutadiene having a low number average molecular weight. Golf balls have been proposed, but none of these proposals satisfy the resilience.

JP-A-62-89750 JP-A-2-268778 JP-A-11-70187 JP 11-319148 A JP 11-164912 A JP-A 63-275356 Japanese Patent Laid-Open No. 3-151985

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a golf ball having a molded article using polybutadiene having high linearity (linearity) of butadiene rubber molecules and having very excellent resilience. And

As a result of intensive studies to achieve the above object, the inventors of the present invention have (a) polybutadiene having 60% or more of cis 1,4 bonds, and its Mooney viscosity (ML _{1 + 4} (100 ° C.)). ) Is ML, and the viscosity of the 5 mass% toluene solution at 25 ° C. is η (mPa · s), ML is 40 or more and 80 or less, and 20 × ML−200 ≧ η ≧ 20 × ML-540 A base rubber compounded with 10 to 90% by mass of polybutadiene synthesized using a rare earth element-based catalyst that satisfies the above relationship, an unsaturated carboxylic acid and / or a metal salt thereof, an organic peroxide, and a predetermined amount The rubber composition blended with the anti-aging agent is very repulsive due to the synergistic effect of combining polybutadiene with very high linearity (linearity) of the rubber molecules blended in the base rubber with the above-mentioned other materials. Excellent addition to It was found that a thermoformed product can be obtained, and the golf ball provided with the thermoformed product has very excellent resilience and can increase the flight distance. It came to make.

Accordingly, the present invention provides the following golf balls.
[Claim 1] (a) Polybutadiene having 60% or more of cis 1,4 bonds, having a Mooney viscosity (ML _{1 + 4} (100 ° C.)) of ML, and a 5 mass% toluene solution at 25 ° C. When the viscosity of η is m (mPa · s), ML is 40 or more and 80 or less,
20 × ML-200 ≧ η ≧ 20 × ML-540
A base rubber containing 10 to 90% by mass of polybutadiene synthesized using a rare earth element-based catalyst satisfying the relationship:
An unsaturated carboxylic acid and / or a metal salt thereof,
Organic peroxides,
A golf composition comprising an anti-aging agent and a heat-molded product of a rubber composition containing 0.2 parts by mass or less of the anti-aging agent with respect to 100 parts by mass of the base rubber. ball.
[Claim 2] The golf ball of claim 1, wherein the polybutadiene of component (a) is polymerized in the presence of a rare earth element catalyst and then reacted with a terminal modifier.
[Claim 3] The above base rubber is obtained by blending 90 to 10% by mass of polybutadiene having a Mooney viscosity of 55 or less as polybutadiene other than the component (a). Golf ball.

  The golf ball of the present invention is excellent in resilience.

Hereinafter, the present invention will be described in more detail. The golf ball of the present invention comprises a heat-molded product of a rubber composition. This rubber composition contains (a) cis as a polybutadiene component as a base rubber. Polybutadiene synthesized by using a rare earth element-based catalyst having 60% or more of 1,4 bonds, its Mooney viscosity (ML _{1 + 4} (100 ° C.)) is ML, and its 5% by mass toluene at 25 ° C. Base rubber containing 10 to 90% by mass of polybutadiene satisfying the relationship of 20 × ML-200 ≧ η ≧ 20 × ML-540 when the viscosity of the solution is η (mPa · s) It is.

  Here, first, the polybutadiene as the component (a) should have a cis 1,4 bond of 60% or more, preferably 80% or more, more preferably 90% or more, and most preferably 95% or more. It is. If there are too few cis 1,4 bonds, the resilience will decrease.

The polybutadiene of the component (a) of the present invention has a Mooney viscosity (ML _{1 + 4} (100 ° C.)) of ML, and a viscosity of a 5 mass% toluene solution at 25 ° C. of η (mPa · s).
η ≧ 20 × ML-540
It is necessary to use polybutadiene that satisfies the above relationship. Polybutadiene with optimized η and ML in this way has a high linearity of the polybutadiene molecule, so it has a very good repulsion against molded products. Sex can be imparted.

In addition, as the upper limit of (a) component η,
η ≦ 20 × ML-200
Preferably, η ≦ 20 × ML-250
It is recommended to use polybutadiene that satisfies this relationship.

  The viscosity η (mPa · s) of a 5% by mass toluene solution at 25 ° C. referred to in the present invention is obtained by dissolving 2.28 g of polybutadiene to be measured in 50 ml of toluene, and then using a standard solution for constituting a viscometer as a standard solution ( It shall mean the value measured under the condition of 25 ° C. with a predetermined viscometer using JIS Z8809).

The Mooney viscosity referred to in the present invention is an industrial viscosity index (JIS-K6300) measured with a Mooney viscometer, which is a kind of rotational plasticity meter, and ML _{1 + 4} as a unit symbol. (100 ° C.) is used. M represents Mooney viscosity, L represents a large rotor (L-type), 1 + 4 represents a preheating time of 1 minute, and a rotor rotation time of 4 minutes, and the measurement was performed at 100 ° C.

The Mooney viscosity (ML _{1 + 4} (100 ° C.)) of the polybutadiene itself as component (a) is 20 or more, preferably 30 or more, more preferably 40 or more, most preferably 50 or more, and the upper limit is 80 or less, preferably 70. In the following, it is recommended that it is 65 or less, most preferably 60 or less.

  The polybutadiene as component (a) is synthesized with a rare earth element-based catalyst, and a known one can be used as the rare earth element-based catalyst.

  For example, a catalyst comprising a combination of a lanthanum series rare earth element compound, an organoaluminum compound, an alumoxane, a halogen-containing compound and, if necessary, a Lewis base can be used.

  Examples of the lanthanum series rare earth element compounds include metal halides having an atomic number of 57 to 71, carboxylates, alcoholates, thioalcolates, and amides.

Examples of the organoaluminum compound include AlR ¹ R ² R ³ (wherein R ¹ , R ² and R ³ may be the same or different, and each represents hydrogen or a hydrocarbon residue having 1 to 8 carbon atoms. Can be used.

（式中、Ｒ⁴は、炭素数１〜２０の炭素原子を含む炭化水素基、ｎは２以上の整数である。）
ハロゲン含有化合物としては、ＡｌＸ_nＲ_3-n（ここで、Ｘはハロゲンを示し、Ｒは、炭素数が１〜２０の炭化水素残基であり、例えば、アルキル基、アリール基、アラルキル基であり、ｎは、１、１．５、２又は３を示す）で示されるアルミニウムハライド、Ｍｅ₃ＳｒＣｌ、Ｍｅ₂ＳｒＣｌ₂、ＭｅＳｒＨＣｌ₂、ＭｅＳｒＣｌ₃などのストロンチウムハライド、その他、四塩化ケイ素、四塩化スズ、四塩化チタンなどの金属ハライド等が用いられる。 Preferred examples of the alumoxane include compounds having a structure represented by the following formula (I) or the following formula (II). In this case, Fine Chemicals, 23, (9), 5 (1994), J. Am. Am. Chem. Soc. 115, 4971 (1993); Am. Chem. Soc. 117, 6465 (1995).

(In the formula, R ⁴ is a hydrocarbon group containing a carbon atom having 1 to 20 carbon atoms, and n is an integer of 2 or more.)
Examples of the halogen-containing compound include AlX _n R _3-n (where X represents halogen, R is a hydrocarbon residue having 1 to 20 carbon atoms, such as an alkyl group, an aryl group, and an aralkyl group. And n represents 1, 1.5, 2 or 3), strontium halides such as Me ₃ SrCl, Me ₂ SrCl ₂ , MeSrHCl ₂ and MeSrCl ₃ , and others, silicon tetrachloride, tetrachloride Metal halides such as tin and titanium tetrachloride are used.

  The Lewis base can be used to complex a lanthanum series rare earth element compound, and examples thereof include acetylacetone and ketone alcohol.

  In the present invention, in particular, the use of a neodymium-based catalyst using a neodymium compound as a lanthanum series rare earth element compound is superior in polybutadiene rubber having a high content of 1,4-cis bonds and a low content of 1,2-vinyl bonds. Since it is obtained by polymerization activity, it is preferable, and specific examples of these rare earth element-based catalysts include those described in JP-A No. 11-35633.

  When butadiene is polymerized in the presence of a rare earth element-based catalyst, a solvent may be used, bulk polymerization or gas phase polymerization may be performed without using a solvent, and the polymerization temperature is usually −30 ° C. to 150 ° C., preferably Can be 10-100 degreeC.

  It is recommended that the polybutadiene as the component (a) of the present invention is obtained by reacting a terminal modifier with the active terminal of the polymer following the polymerization using the rare earth element-based catalyst. Thereby, the cold flow of polybutadiene may be improved, and workability and core durability may be improved.

（式中、Ｙは、酸素原子、チッ素原子又はイオウ原子を示す）、
（４） ハロゲン化イソシアノ化合物、
（５） Ｒ⁸−（ＣＯＯＨ）_m、Ｒ⁹（ＣＯＸ）_m 、Ｒ¹⁰−（ＣＯＯ−Ｒ¹¹）、Ｒ¹²−ＯＣＯＯ−Ｒ¹³、Ｒ¹⁴−（ＣＯＯＣＯ−Ｒ¹⁵）_m 、又は下記式で示されるカルボン酸、酸ハロゲン化物、エステル化合物、炭酸エステル化合物又は酸無水物

（式中、Ｒ⁸〜Ｒ¹⁶は、同一でも異なっていてもよく、炭素数１〜５０の炭素原子を含む炭化水素基、Ｘはハロゲン原子、ｍは１〜５の整数を示す）、
（６） Ｒ¹⁷ｌ Ｍ″（ＯＣＯＲ¹⁸）_4-l 、Ｒ¹⁹ｌＭ″（ＯＣＯ−Ｒ²⁰−ＣＯＯＲ²¹）_4-l、又は下記式で示されるカルボン酸の金属塩

（式中、Ｒ¹⁷〜Ｒ²³は、同一でも異なっていてもよく、炭素数１〜２０の炭素原子を含む炭化水素基、Ｍ″はスズ原子、ケイ素原子又はゲルマニウム原子、ｌは０〜３の整数を示す）等を挙げることができる。 Here, a well-known thing can be used for a terminal modifier, For example, the compound described in following (1)-(6) can be mentioned.
(1) R ⁵ _n M′X _4-n , M′X ₄ , M′X ₃ , R ⁵ _n M ′ (—R ⁶ —COOR ⁷ ) _4-n or R ⁵ _n M ′ (—R ⁶ — COR ⁷ ) _4-n (wherein R ⁵ and R ⁶ may be the same or different and each represents a hydrocarbon group containing 1 to 20 carbon atoms, R ⁷ is a carbon atom having 1 to 20 carbon atoms) Which may contain a carbonyl group or an ester group in the side chain, M ′ is a tin atom, silicon atom, germanium atom or phosphorus atom, X is a halogen atom, and n is an integer of 0 to 3 A halogenated organometallic compound, a halogenated metal compound or an organometallic compound,
(2) A heterocumulene containing a Y = C = Z bond in the molecule (wherein Y represents a carbon atom, oxygen atom, nitrogen atom or sulfur atom, and Z represents an oxygen atom, nitrogen atom or sulfur atom). Compound,
(3) Hetero 3-membered ring compound containing the following bond in the molecule

(Wherein Y represents an oxygen atom, a nitrogen atom or a sulfur atom),
(4) a halogenated isocyano compound,
^{(5) R 8 - (COOH} ) m, R 9 (COX) m, R 10 - (COO-R 11), R 12 -OCOO-R 13, R 14 - (COOCO-R 15) m, or the following formula Carboxylic acid, acid halide, ester compound, carbonate compound or acid anhydride represented by

(In formula, R < ⁸ > -R < ¹⁶ > may be same or different, The hydrocarbon group containing a C1-C50 carbon atom, X is a halogen atom, m shows the integer of 1-5),
(6) R ¹⁷ lM ″ (OCOR ¹⁸ ) _4-l , R ¹⁹ lM ″ (OCO—R ²⁰ —COOR ²¹ ) _4-l , or a metal salt of a carboxylic acid represented by the following formula

(Wherein R ^{17 to} R ²³ may be the same or different, a hydrocarbon group containing a carbon atom having 1 to 20 carbon atoms, M ″ is a tin atom, a silicon atom or a germanium atom, and l is 0 to 3) And the like).

  Specific examples of the terminal modifiers shown in the above (1) to (6) and the reaction method thereof include those described in, for example, JP-A No. 11-35633 or JP-A No. 7-268132, and the like. Can be mentioned.

  The component (a) of the present invention is 10% by mass or more, preferably 20% by mass or more, more preferably 30% by mass or more, most preferably 40% by mass or more, and the upper limit is 90% by mass or less in the base rubber. Preferably it is 80 mass% or less, More preferably, it is 70 mass% or less, Most preferably, it is necessary to mix | blend 60 mass% or less. If the blending amount deviates from the above range, the resilience of the molded product is lowered and the intended effect of the present invention cannot be expected.

  The component (b) in the base rubber of the present invention is not an essential component of the rubber composition of the present invention, but is a component that is optionally blended within a range that does not impair the object of the present invention. Specific examples of the component (b) include polybutadiene rubber (BR), styrene butadiene rubber (SBR), natural rubber, polyisoprene rubber, ethylene propylene diene rubber (EPDM), and the like. These can be used individually by 1 type or in combination of 2 or more types. Since moldability such as resilience and extrusion workability is preferably imparted, the Mooney viscosity other than the component (a) as the component (b) is 55 or less, preferably 50 or less, more preferably 47 or less, and most preferably 45. Hereinafter, a lower limit of 10 or more, preferably 20 or more, more preferably 25 or more, and most preferably 30 or more polybutadiene can be suitably blended.

  It is recommended that the polybutadiene of the component (b) is synthesized with a group VIII catalyst. Specific examples of the group VIII catalyst include the following nickel-based catalyst and cobalt-based catalyst.

  Here, examples of the nickel-based catalyst include a one-component system such as nickel diatomaceous earth, a two-component system such as Raney nickel / titanium tetrachloride, and a three-component system such as nickel compound / organometallic / boron trifluoride etherate. Can be mentioned. As the nickel compound, reduced nickel with support, Raney nickel, nickel oxide, nickel carboxylate, organic nickel complex salt, or the like is used. Examples of the organic metal include trialkylaluminum such as triethylaluminum, tri-n-propylaluminum, triisobutylaluminum, and tri-n-hexylaluminum, n-butyllithium, sec-butyllithium, tert-butyllithium, 1, Examples include alkyl lithium such as 4-dilithium butane, and dialkyl zinc such as diethyl zinc and dibutyl zinc.

  In addition, as cobalt-based catalysts, cobalt and its compounds include Raney cobalt, cobalt chloride, cobalt bromide, cobalt iodide, cobalt oxide, cobalt sulfate, cobalt carbonate, cobalt phosphate, cobalt phthalate, cobalt carbonyl, cobalt acetyl. Examples thereof include acetonate, cobalt diethyldithiocarbamate, cobalt anilinium nitrite, cobalt dinitrosilkyl chloride and the like. Particularly, these compounds and dialkylaluminum monochloride such as diethylaluminum monochloride and diisobutylaluminum monochloride, triethylaluminum, -Trialkylaluminum such as n-propylaluminum, triisobutylaluminum, tri-n-hexylaluminum, ethylaluminum sesquik Aluminum alkyl sesquichloride of chloride etc., can be preferably exemplified a combination of aluminum chloride and the like.

  When the polymerization is performed using the above group VIII-based catalyst, particularly a nickel-based catalyst or a cobalt-based catalyst, usually, the reactor is continuously charged together with a solvent and a butadiene monomer, for example, the reaction temperature is 5 to 60 ° C, A method of operating the reaction pressure so as to obtain the Mooney viscosity can be exemplified by appropriately selecting the reaction pressure within the range of atmospheric pressure to 70 atm.

  When blending other polybutadienes, particularly the component (b), as the base rubber in the component (a) of the present invention, it is usually 90% by mass or less, preferably 80% by mass or less, more preferably 70% by mass. % Or less, most preferably 60% by mass or less, and the lower limit is 10% by mass or more, preferably 20% by mass or more, more preferably 30% by mass or more, and most preferably 40% by mass or more. Recommended from a viewpoint.

  The present invention provides a rubber composition in which an unsaturated carboxylic acid and / or a metal salt thereof and an organic peroxide are blended as essential components with respect to a base rubber prepared by blending the polybutadiene as the component (a). Therefore, when the composition is formed into a heat-molded product, it is possible to reliably impart excellent resilience to the molded product, and to impart excellent resilience to the golf ball having the molded product.

  Here, specific examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, maleic acid, and fumaric acid, and acrylic acid and methacrylic acid are particularly preferable.

  Moreover, as a metal salt of unsaturated carboxylic acid, zinc salts of unsaturated fatty acids such as zinc methacrylate and zinc acrylate, magnesium salts and the like can be blended, and zinc acrylate can be particularly preferably used.

  The compounding amount of these unsaturated carboxylic acids and / or metal salts thereof is usually 10 parts by mass or more, preferably 15 parts by mass or more, more preferably 20 parts by mass or more, and the upper limit is 60 parts by mass with respect to 100 parts by mass of the base rubber. It is preferable that the amount is not more than part by mass, preferably not more than 50 parts by mass, more preferably not more than 45 parts by mass, and most preferably not more than 40 parts by mass. If the blending amount is too small, the resilience is lowered, and if it is too large, it becomes too hard, which may result in an unbearable feel.

  Examples of the organic peroxide of the present invention include commercially available products such as Park Mill D (manufactured by NOF Corporation), Perhexa 3M (manufactured by NOF Corporation), Luperco 231XL (manufactured by Atchem Corporation) and the like. If necessary, two or more different organic peroxides may be mixed and used.

  The compounding amount of the organic peroxide is 0.1 parts by mass or more, preferably 0.3 parts by mass or more, more preferably 0 with respect to 100 parts by mass of the base rubber containing the component (a) as an essential component. .5 parts by mass or more, most preferably 0.7 parts by mass or more, and 5 parts by mass or less as an upper limit, preferably 4 parts by mass or less, more preferably 3 parts by mass or less, and most preferably 2 parts by mass or less. If the amount is too large or too small, it may not be possible to obtain suitable resilience, feel and durability.

  In the rubber composition of the present invention, an inorganic filler for adjusting specific gravity can be used as necessary in addition to the above essential components. As specific examples, zinc oxide, barium sulfate, calcium carbonate and the like can be blended, and the blending amount is usually 1 part by mass or more with respect to 100 parts by mass of the base rubber blending the above component (a) as an essential component. Preferably 3 parts by mass or more, more preferably 5 parts by mass or more, most preferably 7 parts by mass or more, and the upper limit is 130 parts by mass or less, preferably 50 parts by mass or less, more preferably 45 parts by mass or less, most preferably 40 parts by mass. Parts or less is recommended to obtain the proper weight and good resilience.

  Moreover, an anti-aging agent can be mix | blended as an arbitrary component, for example, as a commercial item, Nocrack NS-6, the same NS-30 (made by Ouchi Shinsei Chemical Co., Ltd.), Yoshinox 425 (made by Yoshitomi Pharmaceutical Co., Ltd.), etc. are mentioned. It is done. For 100 parts by mass of the base rubber compounding the component (a) as an essential component, it is usually 0 parts by mass or more, preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, and an upper limit of 0.2 parts by mass. It is recommended from the point that it is possible to obtain suitable resilience and durability of not more than part by mass.

  In the rubber composition of the present invention, an organic sulfur compound can also be blended. For example, it is recommended to blend thiophenol, thionaphthol, halogenated thiophenol, or a metal salt thereof, more specifically, Zinc salts such as pentachlorothiophenol, pentafluorothiophenol, pentabromothiophenol, parachlorothiophenol, pentachlorothiophenol, diphenyl polysulfide having 2 to 4 sulfur, dibenzyl polysulfide, dibenzoyl polysulfide, dibenzothiazoyl Polysulfide, dithiobenzoyl polysulfide and the like can be mentioned, and in particular, zinc salt of pentachlorothiophenol and diphenyl disulfide can be preferably used. Such an organic sulfur compound is blended in an amount of usually about 0.1 parts per 100 parts by weight of the base rubber blended with the above component (a) and the component (b) as a required component. 1 part by mass or more, preferably 0.2 part by mass or more, more preferably 0.5 part by mass or more, and an upper limit of 5 parts by mass or less, preferably 4 parts by mass or less, more preferably 3 parts by mass or less, most preferably 2 It is recommended that it be less than or equal to parts by mass.

  The thermoformed product of the present invention can be obtained by vulcanizing and curing the above-described rubber composition in the same manner as a known golf ball rubber composition. The vulcanization conditions can be carried out, for example, at a vulcanization temperature of 100 to 200 ° C. and a vulcanization time of 10 to 40 minutes.

  In the present invention, the hardness of the heat-molded product can be appropriately adjusted according to the use mode of various golf balls described later, and is not particularly limited, and the cross-sectional hardness is flat from the center to the surface of the molded product. Even in this case, there may be a difference in hardness between the center and the surface of the molded product.

  In addition, the heat-molded product has a deflection amount under a load of 980 N (100 kg), usually 2.0 mm or more, preferably 2.5 mm or more, more preferably 2.8 mm or more, regardless of the form of the golf ball. Preferably it is 3.2 mm or more, the upper limit is 6.0 mm or less, preferably 5.5 mm or less, more preferably 5.0 mm or less, most preferably 4.5 mm or less, and if the deformation is too small When the long shot, especially when the ball of a driver or the like undergoes a large deformation, the spin becomes too large to fly, and if it is too soft, the hit feeling becomes dull and the rebound becomes insufficient and does not fly. In some cases, durability against cracking due to impact may be deteriorated.

  The golf ball of the present invention comprises the above heat-formed product as a component, and the mode of the ball is not particularly limited, and the one-piece golf ball in which the heat-formed product is directly applied to the golf ball, heating A two-piece solid golf ball having a molded product as a solid core and having a cover formed on the surface thereof; a three-piece or more multi-piece solid golf ball having a heat-formed product as a solid core and having two or more layers on the outside; Various modes such as a thread-wound golf ball in which the heat-formed product is applied as a center core can be employed. In particular, two-piece solid golf balls and multi-piece solid golf balls that use the heat-formed product of the present invention as a solid core from the viewpoint of imparting repulsion to the product golf ball by utilizing the characteristics of the heat-formed product. It is recommended that there be a preferred usage.

  In the present invention, when the thermoformed product is the solid core, the diameter of the solid core is 30.0 mm or more, preferably 32.0 mm or more, more preferably 35.0 mm or more, and most preferably 37.0 mm or more. It is recommended that the upper limit is 41.0 mm or less, preferably 40.5 mm or less, more preferably 40.0 mm or less, and most preferably 39.5 mm or less. In particular, the solid core of a two-piece solid golf ball has a diameter of 37. 0.0 mm or more, preferably 37.5 mm or more, more preferably 38.0 mm or more, most preferably 38.5 mm or more, and the upper limit is 41.0 mm or less, preferably 40.5 mm or less, more preferably 40.0 mm or less. The solid core of the three-piece solid golf ball has a diameter of 30.0 mm or less. , Preferably 32.0 mm or more, more preferably 34.0 mm or more, most preferably 35.0 mm or more, and the upper limit is 40.0 mm or less, preferably 39.5 mm or less, more preferably 39.0 mm or less. Is recommended.

  The specific gravity of the solid core is usually 0.9 or more, preferably 1.0 or more, more preferably 1.1 or more, and the upper limit is 1.4 or less, preferably 1.3 or less, more preferably 1.2 or less. It is recommended that there be.

  When the golf ball of the present invention is a two-piece solid golf ball or a multi-piece solid golf ball, it is formed by injection molding or pressure molding a known cover material and intermediate layer material using the heat-molded product as a solid core. Can do.

  Specific examples of these cover materials and intermediate layer material main materials include thermoplastic or thermosetting polyurethane elastomers, polyester elastomers, ionomer resins, polyolefin elastomers, and mixtures thereof. These can be used individually by 1 type or in mixture of 2 or more types, Especially, a thermoplastic polyurethane-type elastomer and an ionomer resin can be mentioned suitably.

  Commercially available products can be used as the thermoplastic polyurethane-based elastomer. For example, diisocyanates such as Pandex T7298, T7295, T7890, TR3080, T8295, T8290 (DIC Bayer Polymer Co., Ltd.) are aliphatic. Or the thing etc. which are aromatic are mentioned. Examples of commercially available ionomer resins include Surlyn 6320 and 8120 (manufactured by DuPont, USA), High Milan 1706, 1605, 1855, 1601, and 1557 (manufactured by Mitsui DuPont Polychemical).

  Furthermore, a polymer such as a thermoplastic elastomer other than the above can be blended as an optional component in the main material of the cover material or intermediate layer material. Specifically, as an optional polymer, a polyamide-based elastomer, a styrene-based block elastomer, a hydrogenated polybutadiene, an ethylene-vinyl acetate (EVA) copolymer, or the like can be blended.

  The two-piece solid golf ball and the multi-piece solid golf ball of the present invention can be manufactured by a known method, and are not particularly limited. The heat-molded product is disposed as a solid core in a predetermined injection mold, and in the case of a two-piece solid golf ball, the cover material is arranged in the order, and in the case of a multi-piece solid golf ball, the intermediate layer material and the cover material are sequentially arranged. A well-known method of injecting the gas in accordance with a predetermined method can be suitably employed. In some cases, the cover material can be manufactured by pressure molding.

  The thickness of the intermediate layer of the multi-piece solid golf ball is 0.5 mm or more, preferably 1.0 mm or more, and the upper limit is 3.0 mm or less, preferably 2.5 mm or less, more preferably 2.0 mm or less, most preferably It is recommended that it is 1.6 mm or less.

  In addition, the cover has a thickness of 0.7 mm or more, preferably 1.0 mm or more, and an upper limit of 3.0 mm or less, preferably 2.5 mm or less, regardless of whether the cover is a two-piece solid golf ball or a multi-piece solid golf ball. It is recommended that the thickness is 2.0 mm or less, and most preferably 1.6 mm or less.

  The multi-piece solid golf ball of the present invention may conform to the golf rules for competition purposes, and may be formed with a diameter of 42.67 mm or more and a weight of 45.93 g or less. The upper limit of the diameter is preferably 44.0 mm or less, more preferably 43.5 mm or less, most preferably 43.0 mm or less, and the lower limit of the weight is preferably 44.5 g or more, particularly preferably 45.0 g or more, more preferably 45. It is recommended that it be at least 1 g, most preferably at least 45.2 g.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.

[Examples 1-7, Comparative Examples 1-6]
The core material shown in Table 2 is prepared for 100 parts by mass of each polybutadiene in which the polybutadiene having physical properties shown in Table 1 of the following types (1) to (7) is blended in the combinations shown in Table 2, and for solid cores. A rubber composition was prepared. In Table 2, parkil D (manufactured by NOF Corporation) was used as dicumyl peroxide, and NOCRACK NS-6 (manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.) was used as the anti-aging agent.

Polybutadiene type (1) Polybutadiene: BR01 manufactured by JSR
(2) Polybutadiene: BR11 manufactured by JSR Corporation
(3) Polybutadiene: UBE101 manufactured by Ube Industries
(4) Polybutadiene: BR18 manufactured by JSR Corporation
(5) Polybutadiene: Prototype grade HCBN-5 manufactured by JSR
(6) Polybutadiene: Prototype grade HCBN-2 manufactured by JSR
(7) Polybutadiene: Prototype grade HCBN-4 manufactured by JSR

  Next, the rubber composition for a solid core was appropriately kneaded with a kneader or a roll, and the extrusion workability when a predetermined amount was extruded was evaluated according to the following criteria. The results are shown in Table 3.

Evaluation of extrusion workability The slag skin and slag shape after extrusion were evaluated according to the following criteria.
5 Slag skin is clean and very good 4 Slag skin is slightly rough but good 3 Slag skin is fluffy but can be extruded 2 Slag skin fluff is very conspicuous but can be extruded 1 Slag shape failure occurs Difficult to extrude quantitatively

For Examples 1-6 and Comparative Examples 1-5, a solid core having a diameter of about 38.9 mm and a weight of about 36.0 g was used as the solid core material. For Example 7 and Comparative Example 6, a diameter of about 35.3 mm was used. Solid cores weighing about 31.0 g were produced.
The pressure molding was performed at 150 ° C. for 20 minutes.

The obtained solid core was examined for deformation amount and resilience when loaded with 980 N (100 kg) as follows. The results are shown in Table 3.
Deflection amount under load of 980N load Deformation amount of solid core under load of 980N (100kg) (mm)
The initial speed is measured with an initial speedometer of the same type as the repulsive official recognition agency USGA. Examples 1 to 6 and Comparative Examples 1 to 5 are based on the values of Comparative Example 4, and Example 7 is Comparative Example 6 The difference in the initial speed when expressed as a reference.

  The solid core is arranged in a predetermined mold, and in Examples 1 to 6 and Comparative Examples 1 to 5, a cover material (Hi-Millan 1601 / Hi-Millan 1557 = 50/50) is injected to have a diameter of about 42.7 mm. A two-piece solid golf ball weighing approximately 45.3 g was manufactured. Further, for Example 7 and Comparative Example 6, an intermediate layer material (Himiran 1706 / Himiran 1605 = 50/50) was injected to produce an intermediate layer coated core having a diameter of about 38.7 mm, and then a predetermined mold was formed. The cover material (High Milan 1650 / Surlin 8120 = 50/50) was injected to produce a three-piece solid golf ball having a diameter of about 42.7 mm and a weight of about 45.3 g.

The flying performance of the obtained golf ball was examined as follows. The results are shown in Table 3.
With a golf ball physical property hitting machine, the carry and total were measured when the driver (W # 1) hit with a head speed of 45 m / s.

Claims (3)

(A) Polybutadiene having 60% or more of cis 1,4 bonds, the Mooney viscosity (ML _{1 + 4} (100 ° C.)) is ML, and the viscosity of a 5 mass% toluene solution at 25 ° C. is η ( mPa · s), ML is 40 or more and 80 or less,
20 × ML-200 ≧ η ≧ 20 × ML-540
A base rubber containing 10 to 90% by mass of polybutadiene synthesized using a rare earth element-based catalyst satisfying the relationship:
An unsaturated carboxylic acid and / or a metal salt thereof,
Organic peroxides,
A golf composition comprising an anti-aging agent and a heat-molded product of a rubber composition containing 0.2 parts by mass or less of the anti-aging agent with respect to 100 parts by mass of the base rubber. ball.   2. The golf ball according to claim 1, wherein the polybutadiene of the component (a) is polymerized under a rare earth element-based catalyst and then reacted with a terminal modifier.   The golf ball according to claim 1, wherein the base rubber is obtained by blending 90 to 10% by mass of polybutadiene having a Mooney viscosity of 55 or less as polybutadiene other than the component (a).