US20020086742A1 - Solid golf ball - Google Patents
Solid golf ball Download PDFInfo
- Publication number
- US20020086742A1 US20020086742A1 US09/978,705 US97870501A US2002086742A1 US 20020086742 A1 US20020086742 A1 US 20020086742A1 US 97870501 A US97870501 A US 97870501A US 2002086742 A1 US2002086742 A1 US 2002086742A1
- Authority
- US
- United States
- Prior art keywords
- golf ball
- core
- weight
- crosslinking agent
- parts
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 239000007787 solid Substances 0.000 title claims abstract description 22
- 229920001971 elastomer Polymers 0.000 claims abstract description 71
- 239000005060 rubber Substances 0.000 claims abstract description 69
- 239000003431 cross linking reagent Substances 0.000 claims abstract description 51
- 239000000203 mixture Substances 0.000 claims abstract description 49
- 239000002245 particle Substances 0.000 claims abstract description 39
- 150000007934 α,β-unsaturated carboxylic acids Chemical class 0.000 claims abstract description 19
- 229910052751 metal Inorganic materials 0.000 claims abstract description 17
- 239000002184 metal Substances 0.000 claims abstract description 17
- 238000004073 vulcanization Methods 0.000 claims abstract description 17
- 239000003999 initiator Substances 0.000 claims abstract description 16
- 150000003839 salts Chemical class 0.000 claims abstract description 16
- 238000000465 moulding Methods 0.000 claims abstract description 12
- 125000004432 carbon atom Chemical group C* 0.000 claims abstract description 6
- XKMZOFXGLBYJLS-UHFFFAOYSA-L zinc;prop-2-enoate Chemical group [Zn+2].[O-]C(=O)C=C.[O-]C(=O)C=C XKMZOFXGLBYJLS-UHFFFAOYSA-L 0.000 claims description 25
- 239000010410 layer Substances 0.000 description 15
- 230000009257 reactivity Effects 0.000 description 14
- 229920005989 resin Polymers 0.000 description 11
- 239000011347 resin Substances 0.000 description 11
- 230000000052 comparative effect Effects 0.000 description 10
- 230000000694 effects Effects 0.000 description 9
- 229920000554 ionomer Polymers 0.000 description 9
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 8
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 description 6
- XMNIXWIUMCBBBL-UHFFFAOYSA-N 2-(2-phenylpropan-2-ylperoxy)propan-2-ylbenzene Chemical compound C=1C=CC=CC=1C(C)(C)OOC(C)(C)C1=CC=CC=C1 XMNIXWIUMCBBBL-UHFFFAOYSA-N 0.000 description 6
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 6
- VZCYOOQTPOCHFL-OWOJBTEDSA-N Fumaric acid Chemical compound OC(=O)\C=C\C(O)=O VZCYOOQTPOCHFL-OWOJBTEDSA-N 0.000 description 6
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 6
- TZCXTZWJZNENPQ-UHFFFAOYSA-L barium sulfate Chemical compound [Ba+2].[O-]S([O-])(=O)=O TZCXTZWJZNENPQ-UHFFFAOYSA-L 0.000 description 6
- 239000003973 paint Substances 0.000 description 6
- 229920002725 thermoplastic elastomer Polymers 0.000 description 6
- VZCYOOQTPOCHFL-UHFFFAOYSA-N trans-butenedioic acid Natural products OC(=O)C=CC(O)=O VZCYOOQTPOCHFL-UHFFFAOYSA-N 0.000 description 6
- 239000011787 zinc oxide Substances 0.000 description 5
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 description 4
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 4
- 239000003963 antioxidant agent Substances 0.000 description 4
- 230000003078 antioxidant effect Effects 0.000 description 4
- 238000004132 cross linking Methods 0.000 description 4
- 239000000945 filler Substances 0.000 description 4
- 150000001451 organic peroxides Chemical class 0.000 description 4
- 229920002857 polybutadiene Polymers 0.000 description 4
- 239000005062 Polybutadiene Substances 0.000 description 3
- OFOBLEOULBTSOW-UHFFFAOYSA-N Propanedioic acid Natural products OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 125000002843 carboxylic acid group Chemical group 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- 238000011156 evaluation Methods 0.000 description 3
- 238000009472 formulation Methods 0.000 description 3
- 239000001530 fumaric acid Substances 0.000 description 3
- VZCYOOQTPOCHFL-UPHRSURJSA-N maleic acid Chemical compound OC(=O)\C=C/C(O)=O VZCYOOQTPOCHFL-UPHRSURJSA-N 0.000 description 3
- 239000011976 maleic acid Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 229910021645 metal ion Inorganic materials 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 230000000704 physical effect Effects 0.000 description 3
- 229920002635 polyurethane Polymers 0.000 description 3
- 239000004814 polyurethane Substances 0.000 description 3
- 150000003254 radicals Chemical class 0.000 description 3
- 238000010998 test method Methods 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- CNGYZEMWVAWWOB-VAWYXSNFSA-N 5-[[4-anilino-6-[bis(2-hydroxyethyl)amino]-1,3,5-triazin-2-yl]amino]-2-[(e)-2-[4-[[4-anilino-6-[bis(2-hydroxyethyl)amino]-1,3,5-triazin-2-yl]amino]-2-sulfophenyl]ethenyl]benzenesulfonic acid Chemical compound N=1C(NC=2C=C(C(\C=C\C=3C(=CC(NC=4N=C(N=C(NC=5C=CC=CC=5)N=4)N(CCO)CCO)=CC=3)S(O)(=O)=O)=CC=2)S(O)(=O)=O)=NC(N(CCO)CCO)=NC=1NC1=CC=CC=C1 CNGYZEMWVAWWOB-VAWYXSNFSA-N 0.000 description 2
- SPBDXSGPUHCETR-JFUDTMANSA-N 8883yp2r6d Chemical compound O1[C@@H](C)[C@H](O)[C@@H](OC)C[C@@H]1O[C@@H]1[C@@H](OC)C[C@H](O[C@@H]2C(=C/C[C@@H]3C[C@@H](C[C@@]4(O[C@@H]([C@@H](C)CC4)C(C)C)O3)OC(=O)[C@@H]3C=C(C)[C@@H](O)[C@H]4OC\C([C@@]34O)=C/C=C/[C@@H]2C)/C)O[C@H]1C.C1C[C@H](C)[C@@H]([C@@H](C)CC)O[C@@]21O[C@H](C\C=C(C)\[C@@H](O[C@@H]1O[C@@H](C)[C@H](O[C@@H]3O[C@@H](C)[C@H](O)[C@@H](OC)C3)[C@@H](OC)C1)[C@@H](C)\C=C\C=C/1[C@]3([C@H](C(=O)O4)C=C(C)[C@@H](O)[C@H]3OC\1)O)C[C@H]4C2 SPBDXSGPUHCETR-JFUDTMANSA-N 0.000 description 2
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- 229920002943 EPDM rubber Polymers 0.000 description 2
- 229920006347 Elastollan Polymers 0.000 description 2
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 2
- 239000005977 Ethylene Substances 0.000 description 2
- 239000005063 High cis polybutadiene Substances 0.000 description 2
- JLVVSXFLKOJNIY-UHFFFAOYSA-N Magnesium ion Chemical compound [Mg+2] JLVVSXFLKOJNIY-UHFFFAOYSA-N 0.000 description 2
- 229920002614 Polyether block amide Polymers 0.000 description 2
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 2
- 229920003182 Surlyn® Polymers 0.000 description 2
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 2
- PTFCDOFLOPIGGS-UHFFFAOYSA-N Zinc dication Chemical compound [Zn+2] PTFCDOFLOPIGGS-UHFFFAOYSA-N 0.000 description 2
- 239000006096 absorbing agent Substances 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 229920001577 copolymer Polymers 0.000 description 2
- LDHQCZJRKDOVOX-NSCUHMNNSA-N crotonic acid Chemical compound C\C=C\C(O)=O LDHQCZJRKDOVOX-NSCUHMNNSA-N 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 239000000806 elastomer Substances 0.000 description 2
- 238000001746 injection moulding Methods 0.000 description 2
- 229910001425 magnesium ion Inorganic materials 0.000 description 2
- 239000000049 pigment Substances 0.000 description 2
- 229920001195 polyisoprene Polymers 0.000 description 2
- -1 polypropylene Polymers 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 229910001415 sodium ion Inorganic materials 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 229920001897 terpolymer Polymers 0.000 description 2
- 229920005992 thermoplastic resin Polymers 0.000 description 2
- 239000004408 titanium dioxide Substances 0.000 description 2
- LDHQCZJRKDOVOX-UHFFFAOYSA-N trans-crotonic acid Natural products CC=CC(O)=O LDHQCZJRKDOVOX-UHFFFAOYSA-N 0.000 description 2
- 229910052725 zinc Inorganic materials 0.000 description 2
- 239000011701 zinc Substances 0.000 description 2
- NALFRYPTRXKZPN-UHFFFAOYSA-N 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane Chemical compound CC1CC(C)(C)CC(OOC(C)(C)C)(OOC(C)(C)C)C1 NALFRYPTRXKZPN-UHFFFAOYSA-N 0.000 description 1
- DMWVYCCGCQPJEA-UHFFFAOYSA-N 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane Chemical compound CC(C)(C)OOC(C)(C)CCC(C)(C)OOC(C)(C)C DMWVYCCGCQPJEA-UHFFFAOYSA-N 0.000 description 1
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- BHPQYMZQTOCNFJ-UHFFFAOYSA-N Calcium cation Chemical compound [Ca+2] BHPQYMZQTOCNFJ-UHFFFAOYSA-N 0.000 description 1
- 229920003304 DuPont™ Surlyn® 8320 Polymers 0.000 description 1
- JOYRKODLDBILNP-UHFFFAOYSA-N Ethyl urethane Chemical compound CCOC(N)=O JOYRKODLDBILNP-UHFFFAOYSA-N 0.000 description 1
- 244000043261 Hevea brasiliensis Species 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 229920000459 Nitrile rubber Polymers 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- NPYPAHLBTDXSSS-UHFFFAOYSA-N Potassium ion Chemical compound [K+] NPYPAHLBTDXSSS-UHFFFAOYSA-N 0.000 description 1
- QOSMNYMQXIVWKY-UHFFFAOYSA-N Propyl levulinate Chemical compound CCCOC(=O)CCC(C)=O QOSMNYMQXIVWKY-UHFFFAOYSA-N 0.000 description 1
- FKNQFGJONOIPTF-UHFFFAOYSA-N Sodium cation Chemical compound [Na+] FKNQFGJONOIPTF-UHFFFAOYSA-N 0.000 description 1
- 229920005655 Surlyn® 6320 Polymers 0.000 description 1
- 229920005657 Surlyn® 9320 Polymers 0.000 description 1
- 125000005396 acrylic acid ester group Chemical group 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 238000000149 argon plasma sintering Methods 0.000 description 1
- 244000001591 balata Species 0.000 description 1
- 235000016302 balata Nutrition 0.000 description 1
- 229910001422 barium ion Inorganic materials 0.000 description 1
- WLZRMCYVCSSEQC-UHFFFAOYSA-N cadmium(2+) Chemical compound [Cd+2] WLZRMCYVCSSEQC-UHFFFAOYSA-N 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 229910001424 calcium ion Inorganic materials 0.000 description 1
- 150000001732 carboxylic acid derivatives Chemical class 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- LSXWFXONGKSEMY-UHFFFAOYSA-N di-tert-butyl peroxide Chemical compound CC(C)(C)OOC(C)(C)C LSXWFXONGKSEMY-UHFFFAOYSA-N 0.000 description 1
- 235000014113 dietary fatty acids Nutrition 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 239000002320 enamel (paints) Substances 0.000 description 1
- 125000004494 ethyl ester group Chemical group 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000000194 fatty acid Substances 0.000 description 1
- 229930195729 fatty acid Natural products 0.000 description 1
- 150000004665 fatty acids Chemical class 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 229910001416 lithium ion Inorganic materials 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 239000000395 magnesium oxide Substances 0.000 description 1
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 1
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 125000005397 methacrylic acid ester group Chemical group 0.000 description 1
- 150000004702 methyl esters Chemical class 0.000 description 1
- 125000004108 n-butyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
- 229920003052 natural elastomer Polymers 0.000 description 1
- 229920001194 natural rubber Polymers 0.000 description 1
- 229920002647 polyamide Polymers 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 229920013716 polyethylene resin Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 229910001414 potassium ion Inorganic materials 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229920001187 thermosetting polymer Polymers 0.000 description 1
- 229910001432 tin ion Inorganic materials 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
- GBNDTYKAOXLLID-UHFFFAOYSA-N zirconium(4+) ion Chemical compound [Zr+4] GBNDTYKAOXLLID-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/04—Oxygen-containing compounds
- C08K5/09—Carboxylic acids; Metal salts thereof; Anhydrides thereof
- C08K5/098—Metal salts of carboxylic acids
-
- A—HUMAN NECESSITIES
- A63—SPORTS; GAMES; AMUSEMENTS
- A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
- A63B37/00—Solid balls; Rigid hollow balls; Marbles
- A63B37/0003—Golf balls
-
- A—HUMAN NECESSITIES
- A63—SPORTS; GAMES; AMUSEMENTS
- A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
- A63B37/00—Solid balls; Rigid hollow balls; Marbles
- A63B37/0003—Golf balls
- A63B37/005—Cores
- A63B37/0051—Materials other than polybutadienes; Constructional details
- A63B37/0054—Substantially rigid, e.g. metal
-
- A—HUMAN NECESSITIES
- A63—SPORTS; GAMES; AMUSEMENTS
- A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
- A63B37/00—Solid balls; Rigid hollow balls; Marbles
- A63B37/0003—Golf balls
- A63B37/007—Characteristics of the ball as a whole
- A63B37/0072—Characteristics of the ball as a whole with a specified number of layers
- A63B37/0073—Solid, i.e. formed of a single piece
Definitions
- the present invention relates to a solid golf ball. More particularly, it relates to a solid golf ball having excellent rebound characteristics while maintaining good shot feel.
- a vulcanized (crosslinked) molded article of rubber composition is typically used for cores of solid golf balls.
- the rubber composition generally comprises a base rubber, such as polybutadiene; a co-crosslinking agent, such as a metal salt of ⁇ , ⁇ -unsaturated carboxylic acid; a vulcanization initiator, such as organic peroxide; a filler, such as zinc oxide, barium sulfate; and the like.
- the vulcanization initiator is thermally dissociated to form free radical.
- the free radical attacks the base rubber and co-crosslinking agent, and the co-crosslinking agent is grafted to a main chain of the base rubber and the base rubber is bonded to each other, thereby crosslinking the rubber composition. Therefore, dispersibility and reactivity of the co-crosslinking agent in the rubber composition have great effect on the physical properties of the solid golf balls.
- Japanese Patent Kokai Publication Nos. 141961/1984 and 92781/1985 suggest that a surface of zinc acrylate particle is coated with a higher fatty acid and a metal salt thereof respectively in order to improve the dispersibility of zinc acrylate in the rubber composition.
- Rubber composition or a solid golf ball using a metal salt of unsaturated carboxylic acid having an average particle size of not more than 5 ⁇ m as the co-crosslinking agent is described in Japanese Patent Kokai Publication Nos.
- a main object of the present invention is to provide a solid golf ball having excellent rebound characteristics while maintaining good shot feel.
- the object described above has been accomplished by adjusting the average particle size and amount of the co-crosslinking agent, and the amount of the vulcanization initiator in the rubber composition for the core to specified ranges, thereby providing a solid golf ball having excellent rebound characteristics while maintaining good shot feel.
- the present invention provides a solid golf ball comprising at least one layer of a core and at least one layer of a cover formed on the core, wherein at least one layer of the core is obtained by vulcanizing and press molding a rubber composition, the rubber composition comprises
- the present invention further provides a one piece-solid golf ball obtained by vulcanizing and molding a rubber composition, wherein the rubber composition comprises
- the co-crosslinking agent is dispersed in the rubber composition as particle (agglomerate) after mixing, and is melted in the base rubber on vulcanization reaction to be fine dispersed.
- the co-crosslinking agent is then crosslinking reacted with the base rubber. Since the co-crosslinking agent having very small average particle size is excessively fine dispersed, the reactivity between the base rubber and co-crosslinking agent is too high, which degrades the reactivity between the base rubbers each other.
- the co-crosslinking agent particle is properly dispersed after mixing the rubber composition by using the co-crosslinking agent having properly large average particle size; and the surface area of the co-crosslinking agent particle is prevented from excessively increasing by maintaining proper particle size thereof.
- the co-crosslinking agent is reacted in state of particle, and the reaction between the co-crosslinking agent each other also occurs in the particle. Therefore, it is considered that there are co-crosslinking agent particles in the rubber composition after crosslinking. Since the crosslinked co-crosslinking agent particle is generally harder than the base rubber, if the co-crosslinking agent is used in an equal amount of each, the hardness of the resulting core is low with the decrease of the particle size thereof. Therefore, by using the co-crosslinking agent having properly large average particle size, the resulting core and golf ball are soft, and shot feel is improved.
- the reactivity between the co-crosslinking agent and the base rubber is restrained from excessively increasing, and the reactivity between the base rubbers each other, which has great effect on rebound characteristics, is improved, by adjusting the average particle size of the co-crosslinking agent to a proper range and decreasing the amount of the vulcanization initiator as compared with the conventional rubber composition, will result in improving the rebound characteristics.
- the solid golf ball of the present invention comprises at least one layer of the core and at least one layer of the cover covering the core.
- the core is basically obtained by press-molding a rubber composition under applied heat by using a method and condition, which has been conventionally used for preparing solid cores of golf balls.
- the rubber composition contains a base rubber, a metal salt of ⁇ , ⁇ -unsaturated carboxylic acid as a co-crosslinking agent, a vulcanization initiator and the like.
- high-cis polybutadiene rubber containing a cis-1,4 bond of not less than 40%, preferably not less than 70%, more preferably not less than 90%, because it imparts excellent rebound characteristics to the resulting golf ball.
- the high-cis polybutadiene rubber may be optionally mixed with natural rubber, polyisoprene rubber, styrene-butadiene rubber, nitrile rubber, ethylene-propylene-diene rubber (EPDM) and the like.
- the co-crosslinking agent can be a metal salt of ⁇ , ⁇ -unsaturated carboxylic acid having 3 to 8 carbon atoms.
- ⁇ , ⁇ -unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, fumaric acid and the like. Preferred is acrylic acid, because it imparts high rebound characteristics to the resulting golf ball.
- the metal of the metal salt include zinc, sodium, magnesium, calcium, aluminum and the like. Preferred is zinc. Therefore, the preferred co-crosslinking agent is zinc acrylate.
- the co-crosslinking agent used in the rubber composition for the core it is required for the co-crosslinking agent used in the rubber composition for the core to have an average particle size of 6 to 30 ⁇ m, preferably 8 to 25 ⁇ m, more preferably 10 to 15 ⁇ m.
- the average particle size is smaller than 6 ⁇ m, the dispersibility of the co-crosslinking agent in the rubber composition is too high, and the technical effects of improving the rebound characteristics accomplished by improving the reactivity between the base rubbers each other are not sufficiently obtained.
- the average particle size is larger than 30 ⁇ m, the co-crosslinking agent particle is too large, and the properties of the resulting golf ball have large variability.
- the amount of the co-crosslinking agent is from 15 to 50 parts by weight, preferably from 20 to 45 parts by weight, more preferably from 20 to 40 parts by weight, based on 100 parts by weight of the base rubber.
- the amount of the co-crosslinking agent is smaller than 15 parts by weight, the core is too soft, and the rebound characteristics are degraded.
- the amount of the co-crosslinking agent is larger than 50 parts by weight, the core is too hard, and the shot feel of the resulting golf ball is poor.
- the vulcanization initiator includes organic peroxide such as dicumyl peroxide, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, di-t-butyl peroxide and the like.
- organic peroxide such as dicumyl peroxide, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, di-t-butyl peroxide and the like.
- the preferred organic peroxide is dicumyl peroxide.
- the organic peroxide is thermally dissociated to form free radical, and the reactivity of crosslinking reaction between the co-crosslinking agent and the base resin is improved.
- the amount of the vulcanization initiator in the rubber composition for the core of the present invention, it is required for the amount of the vulcanization initiator to be within the range of from 0.1 to 1.0 parts by weight, preferably 0.2 to 0.8 parts by weight, more preferably 0.3 to 0.8 parts by weight, based on 100 parts by weight of the base rubber.
- the amount of the vulcanization initiator is smaller than 0.1 parts by weight, the core is too soft, and the rebound characteristics of the resulting golf ball are degraded.
- the amount of the vulcanization initiator when the amount of the vulcanization initiator is larger than 1.0 parts by weight, the reactivity between the base rubber and co-crosslinking agent is high, and the technical effects accomplished by using the co-crosslinking agent having properly large average particle size are sufficiently obtained.
- a volume ratio (V 1 /V 2 ) of a volume (V 1 ) of rubber layer formed by vulcanizing and press molding the rubber composition comprising the base rubber, co-crosslinking agent and vulcanization initiator (it is total volume of rubber layers when it has multi-layer structure) to a volume (V 2 ) of the golf ball to be within the range of from 0.3 to 0.9, preferably from 0.5 to 0.85, more preferably from 0.6 to 0.8.
- the volume ratio is smaller than 0.3, the technical effects of the present invention of improving the rebound characteristics are sufficiently obtained.
- the volume ratio is larger than 0.9, the cover is thin, and the durability of the resulting golf ball is poor.
- the rubber compositions for the core of the golf ball of the present invention can optionally contain filler (such as zinc oxide, barium sulfate, calcium carbonate, magnesium oxide and the like), other components, which have been conventionally used for preparing the core of solid golf balls, such as antioxidant or peptizing agent.
- filler such as zinc oxide, barium sulfate, calcium carbonate, magnesium oxide and the like
- other components which have been conventionally used for preparing the core of solid golf balls, such as antioxidant or peptizing agent.
- the amount of the filler is preferably 5 to 30 parts by weight, and the amount of the antioxidant is preferably 0.2 to 0.5 parts by weight, based on 100 parts by weight of the base rubber.
- the core used in the golf ball of the present invention can be obtained by press-molding and vulcanizing the rubber composition under applied heat in a mold.
- the vulcanizing is conducted at 130 to 180° C. and 2.8 to 9.8 MPa for 10 to 50 minutes.
- the core has a diameter of 30 to 42 mm, preferably 32 to 40 mm.
- the diameter of the core is smaller than 30 mm, the core is too small, and the technical effects accomplished by the presence of the core are not sufficiently obtained. Therefore, the rebound characteristics and durability are degraded.
- the diameter of the core is larger than 42 mm, the thickness of the cover is small, and it is difficult to coat the cover.
- the core it is desired for the core to have a deformation amount when applying from an initial load of 98 N to a final load of 1275 N of 2.0 to 6.0 mm, preferably 2.5 to 5.0 mm, more preferably 2.8 to 4.5 mm.
- the deformation amount is smaller than 2.0 mm, the core is too hard, and the shot feel of the resulting golf ball is poor.
- the deformation amount is larger than 6.0 mm, the core is too soft, and the durability of the resulting golf ball is poor, or the shot feel is poor.
- the core used in the present invention may have single-layer structure, or multi-layer structure, which has two or more layers.
- the rubber composition described above may be used in only one layer or two or more layers, or in any layer.
- the solid golf ball of the present invention can be a one-piece solid golf ball formed by vulcanizing and press molding only the above rubber composition.
- the cover is then coated on the core.
- the cover of the present invention is not limited as long as it is formed from cover material, which has been conventionally used for the cover of golf balls, but includes thermoplastic resin, such as ionomer resin, polyethylene resin, polypropylene resin, thermoplastic elastomer and the like, or mixtures thereof.
- the cover may include thermosetting polyurethane-based elastomer or balata (trans-polyisoprene).
- the ionomer resin may be a copolymer of ethylene and ⁇ , ⁇ -unsaturated carboxylic acid, of which a portion of carboxylic acid groups is neutralized with metal ion, or a terpolymer of ethylene, ⁇ , ⁇ -unsaturated carboxylic acid and ⁇ , ⁇ -unsaturated carboxylic acid ester, of which a portion of carboxylic acid groups is neutralized with metal ion.
- the ⁇ , ⁇ -unsaturated carboxylic acid in the ionomer include acrylic acid, methacrylic acid, fumaric acid, maleic acid, crotonic acid and the like, preferred are acrylic acid and methacrylic acid.
- Examples of the ⁇ , ⁇ -unsaturated carboxylic acid ester in the ionomer include methyl ester, ethyl ester, propyl ester, n-butyl ester and isobutyl ester of acrylic acid, methacrylic acid, fumaric acid, maleic acid, crotonic acid and the like. Preferred are acrylic acid esters and methacrylic acid esters.
- the metal ion which neutralizes a portion of carboxylic acid groups of the copolymer or terpolymer includes a sodium ion, a potassium ion, a lithium ion, a magnesium ion, a calcium ion, a zinc ion, a barium ion, an aluminum, a tin ion, a zirconium ion, cadmium ion, and the like.
- the ionomer resin is not limited, but examples thereof will be shown by a trade name thereof.
- Examples of the ionomer resins, which are commercially available from Mitsui Du Pont Polychemical Co., Ltd. include Hi-milan 1555, Hi-milan 1557, Hi-milan 1605, Hi-milan 1702, Hi-milan 1705, Hi-milan 1706, Hi-milan 1707, Hi-milan 1855 and the like.
- Examples of the ionomer resins, which are commercially available from Du Pont Co. include Surlyn 8945, Surlyn 9945, Surlyn 6320, Surlyn 8320, Surlyn 9320 and the like.
- Examples of the ionomer resins, which are commercially available from Exxon Chemical Co. include Iotek 7010, Iotek 8000 and the like. These ionomer resins may be used alone or in combination.
- thermoplastic elastomers examples include polyamide-based thermoplastic elastomer, which is commercially available from Toray Co., Ltd. under the trade name of “Pebax” (such as “Pebax 2533”); polyester-based thermoplastic elastomer, which is commercially available from Toray-Du Pont Co., Ltd. under the trade name of “Hytrel” (such as “Hytrel 3548”, “Hytrel 4047”); polyurethane-based elastomer, which is commercially available from Takeda Badische Urethane Co., Ltd.
- Elastollan such as “Elastollan ET880”
- polyurethane-based thermoplastic elastomers commercially available from Dainippon Ink & Chemicals Inc., under the trade name “Pandex” (such as “Pandex T-8180”); styrene-based thermoplastic elastomer commercially available from Mitsubishi Chemical Co., Ltd. under the trade name of “Rabalon” (such as “Rabalon SR04”); and the like.
- the cover composition may optionally contain fillers such as barium sulfate, pigments such as titanium dioxide and other additives (such as a dispersant, an antioxidant, a UV absorber, a photostabilizer and a fluorescent agent or a fluorescent brightener, etc.), in addition to the resin component, as long as the addition of the additive does not deteriorate the desired performance of the golf ball cover.
- the amount of the pigment is preferably 0.01 to 10.0 parts by weight, based on the 100 parts by weight of the base resin of the cover.
- the cover of the present invention may be formed by conventional methods, which have been known to the art and used for forming the cover of the golf balls.
- the cover is formed from thermoplastic resin, for example, there can be used a method comprising molding the cover composition into a semi-spherical half-shell in advance, covering the thread wound core with the two half-shells, followed by pressure molding, or a method comprising injection molding the cover composition directly on the thread wound core to cover it.
- the cover In the golf ball of the present invention, it is desired for the cover to have a thickness of 0.5 to 6.0 mm, preferably 1.0 to 4.0 mm, more preferably 1.5 to 3.0 mm.
- the thickness of the cover is smaller than 0.5 mm, the cover is too thin, and the durability is degraded. In addition, the rebound characteristics are also degraded.
- the thickness is larger than 6.0 mm, the shot feel at the time of hitting is poor.
- the cover may be a enamel paint of white color or a desired color, or a clear paint. It is well known in the art that paints of the other color may be coated.
- the paint may optionally contain an antioxidant, a UV absorber, a photostabilizer and a fluorescent agent or a fluorescent brightener, etc.
- a given weight of zinc oxide and triple weight thereof of toluene were charged in a reactor, and then suspended with stirring.
- Acrylic acid was dropped into the reactor in twice mole ratio of the zinc acrylate to react at the room temperature for 1 hour with stirring.
- the product was heated under a vacuum condition to distill off toluene and formed water, and bulk zinc acrylate was obtained.
- cover compositions were covered on the resulting core by injection molding to form a cover layer having a thickness of 2.3 mm. Then, clear urethane paint was applied on the surface to produce golf ball having a diameter of 42.7 mm and weight of 45.4 g. With respect to the resulting golf balls, the deformation amount, coefficient of restitution, flight performance (initial velocity, spin amount and shot feel were measured or evaluated. The results are shown in Tables 5 and 6. The test methods are as follows.
- the average particle size of the co-crosslinking agent is determined by using a laser diffraction/light scattering particle size distribution analyzer LA-910, available from HORIBA, Ltd.
- the deformation amount of core was determined by measuring a deformation amount when applying from an initial load of 98 N to a final load of 1275 N on the core.
- a aluminum cylinder having a weight of 198.4 g was struck at a speed of 45 cm/sec against a golf ball, and the velocity of the cylinder and the golf ball before and after the strike were measured.
- the coefficient of restitution of the golf ball was calculated from the velocity and the weight of both the cylinder and the golf ball.
- a higher index corresponded to a higher rebound characteristic, and thus a good result.
- the shot feel of the golf ball is evaluated by 20 amateur golfers having a handicap of not more than 15 according to a practical hitting test using a No. 1 wood club (W#1, a driver).
- W#1 No. 1 wood club
- the results shown in the Tables below are based on the fact that the most golfers evaluated with the same criterion about shot feel.
- the evaluation criteria are as follows.
- the amount of the zinc acrylate is too small, and the resulting golf ball is too soft, which reduces the coefficient of restitution.
- the amount of the dicumyl peroxide is large, and the reactivity between the zinc acrylate and polybutadiene is too high, and the technical effects accomplished by using the co-crosslinking agent having large average particle size are sufficiently obtained, which largely reduces the coefficient of restitution.
- the shot feel is heavy and poor such that rebound characteristics are poor.
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Abstract
The present invention provides a solid golf ball having excellent rebound characteristics while maintaining good shot feel. The present invention relates to a solid golf ball comprising at least one layer of a core and at least one layer of a cover formed on the core, wherein at least one layer of the core is obtained by vulcanizing and molding a rubber composition, the rubber composition comprises (a) based on 100 parts by weight of a base rubber, (b) from 15 to 50 parts by weight of a metal salt of α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms as a co-crosslinking agent, and the metal salt of α,β-unsaturated carboxylic acid has an average particle size of 6 to 30 μm, and (c) 0.1 to 1.0 parts by weight of a vulcanization initiator.
Description
- The present invention relates to a solid golf ball. More particularly, it relates to a solid golf ball having excellent rebound characteristics while maintaining good shot feel.
- A vulcanized (crosslinked) molded article of rubber composition is typically used for cores of solid golf balls. The rubber composition generally comprises a base rubber, such as polybutadiene; a co-crosslinking agent, such as a metal salt of α,β-unsaturated carboxylic acid; a vulcanization initiator, such as organic peroxide; a filler, such as zinc oxide, barium sulfate; and the like. In the rubber composition for the core, the vulcanization initiator is thermally dissociated to form free radical. It is considered that the free radical attacks the base rubber and co-crosslinking agent, and the co-crosslinking agent is grafted to a main chain of the base rubber and the base rubber is bonded to each other, thereby crosslinking the rubber composition. Therefore, dispersibility and reactivity of the co-crosslinking agent in the rubber composition have great effect on the physical properties of the solid golf balls.
- It has been suggested to improve the dispersibility of the co-crosslinking agent by coating the co-crosslinking agent particle or by reducing an average particle size thereof (Japanese Patent Kokai Publication Nos. 141961/1984, 92781/1985, 196661/1996, 235413/1997, 57068/1999, 57069/1999 and the like).
- Japanese Patent Kokai Publication Nos. 141961/1984 and 92781/1985 suggest that a surface of zinc acrylate particle is coated with a higher fatty acid and a metal salt thereof respectively in order to improve the dispersibility of zinc acrylate in the rubber composition. Rubber composition or a solid golf ball using a metal salt of unsaturated carboxylic acid having an average particle size of not more than 5 μm as the co-crosslinking agent is described in Japanese Patent Kokai Publication Nos. 196661/1996, 235413/1997 and 57068/1999, and rubber composition or a solid golf ball using zinc acrylate having a particle size distribution of 0.1 to 5 μm and an average particle size of 1 to 4.5 μm as the co-crosslinking agent is described in Japanese Patent Kokai Publication No. 57069/1999.
- However, intermolecular bond between the base rubbers each other have greater effect on rebound characteristics of the resulting golf ball than that between the base rubber and co-crosslinking agent. Therefore, the dispersibility is excessively improved by excessively reducing the particle size of the co-crosslinking agent, and the rebound characteristics are not sufficiently obtained. The reason is considered that surface area of the co-crosslinking agent is too large, and the reactivity between the base rubber and co-crosslinking agent is high, which degrades the reactivity between the base rubbers each other.
- A main object of the present invention is to provide a solid golf ball having excellent rebound characteristics while maintaining good shot feel.
- According to the present invention, the object described above has been accomplished by adjusting the average particle size and amount of the co-crosslinking agent, and the amount of the vulcanization initiator in the rubber composition for the core to specified ranges, thereby providing a solid golf ball having excellent rebound characteristics while maintaining good shot feel.
- The present invention provides a solid golf ball comprising at least one layer of a core and at least one layer of a cover formed on the core, wherein at least one layer of the core is obtained by vulcanizing and press molding a rubber composition, the rubber composition comprises
- (a) based on 100 parts by weight of a base rubber,
- (b) from 15 to 50 parts by weight of a metal salt of α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms as a co-crosslinking agent, and the metal salt of α,β-unsaturated carboxylic acid has an average particle size of 6 to 30 μm, and
- (c) 0.1 to 1.0 parts by weight of a vulcanization initiator.
- The present invention further provides a one piece-solid golf ball obtained by vulcanizing and molding a rubber composition, wherein the rubber composition comprises
- (a) based on 100 parts by weight of a base rubber,
- (b) from 15 to 50 parts by weight of a metal salt of α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms as a co-crosslinking agent, and the metal salt of α,β-unsaturated carboxylic acid has an average particle size of 6 to 30 μm, and
- (c) 0.1 to 1.0 parts by weight of a vulcanization initiator.
- The co-crosslinking agent is dispersed in the rubber composition as particle (agglomerate) after mixing, and is melted in the base rubber on vulcanization reaction to be fine dispersed. The co-crosslinking agent is then crosslinking reacted with the base rubber. Since the co-crosslinking agent having very small average particle size is excessively fine dispersed, the reactivity between the base rubber and co-crosslinking agent is too high, which degrades the reactivity between the base rubbers each other. In the present invention, the co-crosslinking agent particle is properly dispersed after mixing the rubber composition by using the co-crosslinking agent having properly large average particle size; and the surface area of the co-crosslinking agent particle is prevented from excessively increasing by maintaining proper particle size thereof. By decreasing the amount of the vulcanization initiator in combination with thereof, the present inventors discovered that the reactivity between the co-crosslinking agent and the base rubber is restrained from excessively increasing, and the reactivity between the base rubbers each other is improved, which improves the rebound characteristics.
- The co-crosslinking agent is reacted in state of particle, and the reaction between the co-crosslinking agent each other also occurs in the particle. Therefore, it is considered that there are co-crosslinking agent particles in the rubber composition after crosslinking. Since the crosslinked co-crosslinking agent particle is generally harder than the base rubber, if the co-crosslinking agent is used in an equal amount of each, the hardness of the resulting core is low with the decrease of the particle size thereof. Therefore, by using the co-crosslinking agent having properly large average particle size, the resulting core and golf ball are soft, and shot feel is improved.
- In the golf ball of the present invention, it is discovered that the reactivity between the co-crosslinking agent and the base rubber is restrained from excessively increasing, and the reactivity between the base rubbers each other, which has great effect on rebound characteristics, is improved, by adjusting the average particle size of the co-crosslinking agent to a proper range and decreasing the amount of the vulcanization initiator as compared with the conventional rubber composition, will result in improving the rebound characteristics.
- The solid golf ball of the present invention comprises at least one layer of the core and at least one layer of the cover covering the core. The core is basically obtained by press-molding a rubber composition under applied heat by using a method and condition, which has been conventionally used for preparing solid cores of golf balls. The rubber composition contains a base rubber, a metal salt of α,β-unsaturated carboxylic acid as a co-crosslinking agent, a vulcanization initiator and the like.
- As the base rubber used for the core of the present invention, preferred is high-cis polybutadiene rubber containing a cis-1,4 bond of not less than 40%, preferably not less than 70%, more preferably not less than 90%, because it imparts excellent rebound characteristics to the resulting golf ball. The high-cis polybutadiene rubber may be optionally mixed with natural rubber, polyisoprene rubber, styrene-butadiene rubber, nitrile rubber, ethylene-propylene-diene rubber (EPDM) and the like.
- The co-crosslinking agent can be a metal salt of α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms. Examples of the α,β-unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, fumaric acid and the like. Preferred is acrylic acid, because it imparts high rebound characteristics to the resulting golf ball. Examples of the metal of the metal salt include zinc, sodium, magnesium, calcium, aluminum and the like. Preferred is zinc. Therefore, the preferred co-crosslinking agent is zinc acrylate.
- In the golf ball of the present invention, it is required for the co-crosslinking agent used in the rubber composition for the core to have an average particle size of 6 to 30 μm, preferably 8 to 25 μm, more preferably 10 to 15 μm. When the average particle size is smaller than 6 μm, the dispersibility of the co-crosslinking agent in the rubber composition is too high, and the technical effects of improving the rebound characteristics accomplished by improving the reactivity between the base rubbers each other are not sufficiently obtained. On the other hand, when the average particle size is larger than 30 μm, the co-crosslinking agent particle is too large, and the properties of the resulting golf ball have large variability. The amount of the co-crosslinking agent is from 15 to 50 parts by weight, preferably from 20 to 45 parts by weight, more preferably from 20 to 40 parts by weight, based on 100 parts by weight of the base rubber. When the amount of the co-crosslinking agent is smaller than 15 parts by weight, the core is too soft, and the rebound characteristics are degraded. On the other hand, when the amount of the co-crosslinking agent is larger than 50 parts by weight, the core is too hard, and the shot feel of the resulting golf ball is poor.
- The vulcanization initiator includes organic peroxide such as dicumyl peroxide, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, di-t-butyl peroxide and the like. The preferred organic peroxide is dicumyl peroxide. The organic peroxide is thermally dissociated to form free radical, and the reactivity of crosslinking reaction between the co-crosslinking agent and the base resin is improved.
- In the rubber composition for the core of the present invention, it is required for the amount of the vulcanization initiator to be within the range of from 0.1 to 1.0 parts by weight, preferably 0.2 to 0.8 parts by weight, more preferably 0.3 to 0.8 parts by weight, based on 100 parts by weight of the base rubber. When the amount of the vulcanization initiator is smaller than 0.1 parts by weight, the core is too soft, and the rebound characteristics of the resulting golf ball are degraded. On the other hand, when the amount of the vulcanization initiator is larger than 1.0 parts by weight, the reactivity between the base rubber and co-crosslinking agent is high, and the technical effects accomplished by using the co-crosslinking agent having properly large average particle size are sufficiently obtained.
- It is desired for a volume ratio (V1/V2) of a volume (V1) of rubber layer formed by vulcanizing and press molding the rubber composition comprising the base rubber, co-crosslinking agent and vulcanization initiator (it is total volume of rubber layers when it has multi-layer structure) to a volume (V2) of the golf ball to be within the range of from 0.3 to 0.9, preferably from 0.5 to 0.85, more preferably from 0.6 to 0.8. When the volume ratio is smaller than 0.3, the technical effects of the present invention of improving the rebound characteristics are sufficiently obtained. On the other hand, when the volume ratio is larger than 0.9, the cover is thin, and the durability of the resulting golf ball is poor.
- The rubber compositions for the core of the golf ball of the present invention can optionally contain filler (such as zinc oxide, barium sulfate, calcium carbonate, magnesium oxide and the like), other components, which have been conventionally used for preparing the core of solid golf balls, such as antioxidant or peptizing agent. If used, the amount of the filler is preferably 5 to 30 parts by weight, and the amount of the antioxidant is preferably 0.2 to 0.5 parts by weight, based on 100 parts by weight of the base rubber.
- The core used in the golf ball of the present invention can be obtained by press-molding and vulcanizing the rubber composition under applied heat in a mold. The vulcanizing is conducted at 130 to 180° C. and 2.8 to 9.8 MPa for 10 to 50 minutes.
- In the golf ball of the present invention, the core has a diameter of 30 to 42 mm, preferably 32 to 40 mm. When the diameter of the core is smaller than 30 mm, the core is too small, and the technical effects accomplished by the presence of the core are not sufficiently obtained. Therefore, the rebound characteristics and durability are degraded. On the other hand, when the diameter of the core is larger than 42 mm, the thickness of the cover is small, and it is difficult to coat the cover.
- In the golf ball of the present invention, it is desired for the core to have a deformation amount when applying from an initial load of 98 N to a final load of 1275 N of 2.0 to 6.0 mm, preferably 2.5 to 5.0 mm, more preferably 2.8 to 4.5 mm. When the deformation amount is smaller than 2.0 mm, the core is too hard, and the shot feel of the resulting golf ball is poor. On the other hand, when the deformation amount is larger than 6.0 mm, the core is too soft, and the durability of the resulting golf ball is poor, or the shot feel is poor.
- The core used in the present invention may have single-layer structure, or multi-layer structure, which has two or more layers. When the core has the multi-layer structure, the rubber composition described above may be used in only one layer or two or more layers, or in any layer. The solid golf ball of the present invention can be a one-piece solid golf ball formed by vulcanizing and press molding only the above rubber composition.
- The cover is then coated on the core. The cover of the present invention is not limited as long as it is formed from cover material, which has been conventionally used for the cover of golf balls, but includes thermoplastic resin, such as ionomer resin, polyethylene resin, polypropylene resin, thermoplastic elastomer and the like, or mixtures thereof. In addition, the cover may include thermosetting polyurethane-based elastomer or balata (trans-polyisoprene).
- The ionomer resin may be a copolymer of ethylene and α,β-unsaturated carboxylic acid, of which a portion of carboxylic acid groups is neutralized with metal ion, or a terpolymer of ethylene, α,β-unsaturated carboxylic acid and α,β-unsaturated carboxylic acid ester, of which a portion of carboxylic acid groups is neutralized with metal ion. Examples of the α,β-unsaturated carboxylic acid in the ionomer include acrylic acid, methacrylic acid, fumaric acid, maleic acid, crotonic acid and the like, preferred are acrylic acid and methacrylic acid. Examples of the α,β-unsaturated carboxylic acid ester in the ionomer include methyl ester, ethyl ester, propyl ester, n-butyl ester and isobutyl ester of acrylic acid, methacrylic acid, fumaric acid, maleic acid, crotonic acid and the like. Preferred are acrylic acid esters and methacrylic acid esters. The metal ion which neutralizes a portion of carboxylic acid groups of the copolymer or terpolymer includes a sodium ion, a potassium ion, a lithium ion, a magnesium ion, a calcium ion, a zinc ion, a barium ion, an aluminum, a tin ion, a zirconium ion, cadmium ion, and the like. Preferred are sodium ions, zinc ions, magnesium ions and the like, in view of rebound characteristics, durability and the like.
- The ionomer resin is not limited, but examples thereof will be shown by a trade name thereof. Examples of the ionomer resins, which are commercially available from Mitsui Du Pont Polychemical Co., Ltd. include Hi-milan 1555, Hi-milan 1557, Hi-milan 1605, Hi-milan 1702, Hi-milan 1705, Hi-milan 1706, Hi-milan 1707, Hi-milan 1855 and the like. Examples of the ionomer resins, which are commercially available from Du Pont Co., include Surlyn 8945, Surlyn 9945, Surlyn 6320, Surlyn 8320, Surlyn 9320 and the like. Examples of the ionomer resins, which are commercially available from Exxon Chemical Co., include Iotek 7010, Iotek 8000 and the like. These ionomer resins may be used alone or in combination.
- Examples of the thermoplastic elastomers include polyamide-based thermoplastic elastomer, which is commercially available from Toray Co., Ltd. under the trade name of “Pebax” (such as “Pebax 2533”); polyester-based thermoplastic elastomer, which is commercially available from Toray-Du Pont Co., Ltd. under the trade name of “Hytrel” (such as “Hytrel 3548”, “Hytrel 4047”); polyurethane-based elastomer, which is commercially available from Takeda Badische Urethane Co., Ltd. under the trade name of “Elastollan” (such as “Elastollan ET880”); polyurethane-based thermoplastic elastomers commercially available from Dainippon Ink & Chemicals Inc., under the trade name “Pandex” (such as “Pandex T-8180”); styrene-based thermoplastic elastomer commercially available from Mitsubishi Chemical Co., Ltd. under the trade name of “Rabalon” (such as “Rabalon SR04”); and the like.
- In the golf ball of the present invention, the cover composition may optionally contain fillers such as barium sulfate, pigments such as titanium dioxide and other additives (such as a dispersant, an antioxidant, a UV absorber, a photostabilizer and a fluorescent agent or a fluorescent brightener, etc.), in addition to the resin component, as long as the addition of the additive does not deteriorate the desired performance of the golf ball cover. If used, the amount of the pigment is preferably 0.01 to 10.0 parts by weight, based on the 100 parts by weight of the base resin of the cover.
- The cover of the present invention may be formed by conventional methods, which have been known to the art and used for forming the cover of the golf balls. When the cover is formed from thermoplastic resin, for example, there can be used a method comprising molding the cover composition into a semi-spherical half-shell in advance, covering the thread wound core with the two half-shells, followed by pressure molding, or a method comprising injection molding the cover composition directly on the thread wound core to cover it.
- In the golf ball of the present invention, it is desired for the cover to have a thickness of 0.5 to 6.0 mm, preferably 1.0 to 4.0 mm, more preferably 1.5 to 3.0 mm. When the thickness of the cover is smaller than 0.5 mm, the cover is too thin, and the durability is degraded. In addition, the rebound characteristics are also degraded. On the other hand, when the thickness is larger than 6.0 mm, the shot feel at the time of hitting is poor.
- At the time of molding the cover, many depressions called “dimples” are formed on the surface of the golf ball. Furthermore, paint finishing or marking with a stamp may be optionally provided after the cover is molded for commercial purposes. The number, shape and size of the dimple are not specially limited. The paint may be a enamel paint of white color or a desired color, or a clear paint. It is well known in the art that paints of the other color may be coated. The paint may optionally contain an antioxidant, a UV absorber, a photostabilizer and a fluorescent agent or a fluorescent brightener, etc.
- The following Examples and Comparative Examples further illustrate the present invention in detail but are not to be construed to limit the scope of the present invention.
- A given weight of zinc oxide and triple weight thereof of toluene were charged in a reactor, and then suspended with stirring. Acrylic acid was dropped into the reactor in twice mole ratio of the zinc acrylate to react at the room temperature for 1 hour with stirring. After reacting, the product was heated under a vacuum condition to distill off toluene and formed water, and bulk zinc acrylate was obtained.
- The resulting bulk zinc acrylate was ground using a grinder, and classified by a sieve to obtain four sorts of zinc acrylates I to IV. The average particle size of the resulting four sorts zinc acrylates was determined. The test method is described later.
TABLE 1 Average particle size (μm) Zinc acrylate I 2.9 Zinc acrylate II 5.2 Zinc acrylate III 8.6 Zinc acrylate IV 11.4 - The rubber compositions for core having the formulation shown in Tables 1 and 2 with the resulting the zinc acrylates I to IV were mixed by using a kneader and mixing roll, and the mixtures were then press molded at 160° C. for 30 minutes in a mold to obtain cores having a diameter of 38.4 mm and a weight of 34.6 g.
TABLE 2 (parts by weight) Example No. Com. Ex. No. Core composition 1 2 3 4 1 BR - 01 *1 100 100 100 100 100 Zinc acrylate I — — — — 27 Zinc acrylate II — — — — — Zinc acrylate III 27 36 — — — Zinc acrylate IV — — 27 36 — Zinc oxide 20 17 20 17 20 Dicumyl peroxide 0.6 0.3 0.8 0.4 0.3 -
TABLE 3 (parts by weight) Comparative Example No. Core composition 2 3 4 5 6 7 BR-01 *1 100 100 100 100 100 100 Zinc acrylate I — — — — — — Zinc acrylate II 27 — — — — — Zinc acrylate III — 10 55 — — 36 Zinc acrylate IV — — — 10 55 — Zinc oxide 20 26 10 26 10 17 Dicumyl peroxide 0.4 1.5 0.08 1.7 0.08 1.2 - The formulation materials shown in Table 4 were mixed using a kneading type twin-screw extruder to obtain pelletized cover compositions. The extrusion condition was,
- a screw diameter of 45 mm,
- a screw speed of 200 rpm, and
- a screw L/D of 35.
- The formulation materials were heated at 200 to 260° C. at the die position of the extruder.
TABLE 4 Cover composition Amount (parts by weight) Hi-milan 1605 *2 50 Hi-milan 1706 *3 50 Titanium dioxide 2 - The cover compositions were covered on the resulting core by injection molding to form a cover layer having a thickness of 2.3 mm. Then, clear urethane paint was applied on the surface to produce golf ball having a diameter of 42.7 mm and weight of 45.4 g. With respect to the resulting golf balls, the deformation amount, coefficient of restitution, flight performance (initial velocity, spin amount and shot feel were measured or evaluated. The results are shown in Tables 5 and 6. The test methods are as follows.
- (1) Average Particle Size
- The average particle size of the co-crosslinking agent is determined by using a laser diffraction/light scattering particle size distribution analyzer LA-910, available from HORIBA, Ltd.
- (2) Deformation Amount
- The deformation amount of core was determined by measuring a deformation amount when applying from an initial load of 98 N to a final load of 1275 N on the core.
- (3) Coefficient of Restitution
- A aluminum cylinder having a weight of 198.4 g was struck at a speed of 45 cm/sec against a golf ball, and the velocity of the cylinder and the golf ball before and after the strike were measured. The coefficient of restitution of the golf ball was calculated from the velocity and the weight of both the cylinder and the golf ball. The measurement was conducted by using 12 golf balls for each sample (n=12), with the mean value being taken as the coefficient of restitution of each ball and expressed as an index, with the value of the index in Comparative Example 1 being taken as 100. A higher index corresponded to a higher rebound characteristic, and thus a good result.
- (4) Shot Feel
- The shot feel of the golf ball is evaluated by 20 amateur golfers having a handicap of not more than 15 according to a practical hitting test using a No. 1 wood club (W#1, a driver). The results shown in the Tables below are based on the fact that the most golfers evaluated with the same criterion about shot feel. The evaluation criteria are as follows.
- Evaluation criteria I (Impact force)
- ∘: The golfers felt that the golf ball has good shot feel such that impact force at the time of hitting is small.
- Δ: The golfers felt that the golf ball has fairly good shot feel such that impact force at the time of hitting is slightly large.
- x: The golfers felt that the golf ball has poor shot feel such that impact force at the time of hitting is large.
- Evaluation criteria II (Rebound Characteristics)
- ∘: The golfers felt that the golf ball has good shot feel such that rebound characteristics are good.
- Δ: The golfers felt that the golf ball has slightly heavy and fairly good shot feel such that rebound characteristics are small.
- x: The golfers felt that the golf ball has heavy and poor shot feel such that rebound characteristics are poor.
TABLE 5 Com. Example No. Ex. No. Test item 1 2 3 4 1 (Core) Deformation amount 3.72 3.56 3.70 3.48 3.75 (mm) (Physical properties of golf ball) Coefficient of restitution 102 103 103 105 100 Shot feel Impact force ∘ ∘ ∘ ∘ ∘ Rebound ∘ ∘ ∘ ∘ Δ -
TABLE 6 Comparative Example No. Test item 2 3 4 5 6 7 (Core) Deformation 3.74 4.21 3.25 4.35 3.38 2.92 amount (mm) (Physical properties of golf ball) Coefficient of 100 95 103 96 104 105 restitution Shot Impact ∘ ∘ x ∘ x x feel force Re- Δ x ∘ x ∘ ∘ bound - As is apparent from the results shown in Tables 5 and 6, the golf balls of the present invention of Examples 1 to 4 have excellent rebound characteristics and good shot feel when compared with the golf balls of Comparative Examples 1 to 7.
- On the other hand, in the golf balls of Comparative Examples 1 and 2, the average particle size of zinc acrylate is too small, and the dispersibility of the zinc acrylate in the rubber composition is too high. Therefore the technical effects of improving the rebound characteristics accomplished by improving the reactivity between the base rubbers each other are sufficiently obtained, which reduces the coefficient of restitution.
- In the golf balls of Comparative Examples 3 and 5, the amount of the zinc acrylate is too small, and the resulting golf ball is too soft, which reduces the coefficient of restitution. The amount of the dicumyl peroxide is large, and the reactivity between the zinc acrylate and polybutadiene is too high, and the technical effects accomplished by using the co-crosslinking agent having large average particle size are sufficiently obtained, which largely reduces the coefficient of restitution. In addition, the shot feel is heavy and poor such that rebound characteristics are poor.
- In the golf balls of Comparative Examples 4 and 6, the amount of the zinc acrylate is large, and the resulting golf ball is too hard and the shot feel is poor shot feel such that impact force at the time of hitting is large. In the golf ball of Comparative Example 7, the amount of dicumyl peroxide is large, and the resulting golf ball is too hard and the shot feel is poor such that impact force at the time of hitting is large.
Claims (4)
1. A solid golf ball comprising at least one layer of a core and at least one layer of a cover formed on the core, wherein at least one layer of the core is obtained by vulcanizing and molding a rubber composition, the rubber composition comprises
(a) based on 100 parts by weight of a base rubber,
(b) from 15 to 50 parts by weight of a metal salt of α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms as a co-crosslinking agent, and the metal salt of α,β-unsaturated carboxylic acid has an average particle size of 6 to 30 μm, and
(c) 0.1 to 1.0 parts by weight of a vulcanization initiator.
2. The solid golf ball according to claim 1 , wherein the co-crosslinking agent is zinc acrylate.
3. The solid golf ball according to claim 1 , wherein the co-crosslinking agent has an average particle size of 8 to 25 μm.
4. A one piece-solid golf ball obtained by vulcanizing and molding a rubber composition, wherein the rubber composition comprises
(a) based on 100 parts by weight of a base rubber,
(b) from 15 to 50 parts by weight of a metal salt of α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms as a co-crosslinking agent, and the metal salt of α,β-unsaturated carboxylic acid has an average particle size of 6 to 30 μm, and (c) 0.1 to 1.0 parts by weight of a vulcanization initiator.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP317765/2000 | 2000-10-18 | ||
JP2000317765A JP2002119613A (en) | 2000-10-18 | 2000-10-18 | Solid golf ball |
Publications (1)
Publication Number | Publication Date |
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US20020086742A1 true US20020086742A1 (en) | 2002-07-04 |
Family
ID=18796499
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US09/978,705 Abandoned US20020086742A1 (en) | 2000-10-18 | 2001-10-18 | Solid golf ball |
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US (1) | US20020086742A1 (en) |
JP (1) | JP2002119613A (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20040152540A1 (en) * | 2003-01-24 | 2004-08-05 | Kazuhisa Fushihara | Golf ball |
US20170028262A1 (en) * | 2015-07-31 | 2017-02-02 | Dunlop Sports Co. Ltd. | Golf ball |
US9694249B2 (en) | 2012-06-01 | 2017-07-04 | Dunlaop Sports Co., Ltd. | Method for manufacturing golf ball |
US9849344B2 (en) * | 2015-08-07 | 2017-12-26 | Dunlop Sports Co. Ltd. | Golf ball |
US20180178078A1 (en) * | 2016-12-28 | 2018-06-28 | Bridgestone Sports Co., Ltd. | Golf ball |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4847648B2 (en) * | 2001-06-29 | 2011-12-28 | ブリヂストンスポーツ株式会社 | Zinc acrylate composition, method for producing the same, and golf ball using the composition |
CN102485295B (en) * | 2010-12-03 | 2014-11-05 | 住胶体育用品株式会社 | Golf ball |
JP6425398B2 (en) * | 2014-03-28 | 2018-11-21 | 住友ゴム工業株式会社 | Golf ball |
-
2000
- 2000-10-18 JP JP2000317765A patent/JP2002119613A/en active Pending
-
2001
- 2001-10-18 US US09/978,705 patent/US20020086742A1/en not_active Abandoned
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20040152540A1 (en) * | 2003-01-24 | 2004-08-05 | Kazuhisa Fushihara | Golf ball |
US7056231B2 (en) | 2003-01-24 | 2006-06-06 | Sri Sports Limited | Golf ball |
US9694249B2 (en) | 2012-06-01 | 2017-07-04 | Dunlaop Sports Co., Ltd. | Method for manufacturing golf ball |
US20170028262A1 (en) * | 2015-07-31 | 2017-02-02 | Dunlop Sports Co. Ltd. | Golf ball |
US10213655B2 (en) * | 2015-07-31 | 2019-02-26 | Sumitomo Rubber Industries, Ltd. | Golf ball |
US9849344B2 (en) * | 2015-08-07 | 2017-12-26 | Dunlop Sports Co. Ltd. | Golf ball |
US10894191B2 (en) | 2015-08-07 | 2021-01-19 | Sumitomo Rubber Industries, Ltd. | Golf ball |
US20180178078A1 (en) * | 2016-12-28 | 2018-06-28 | Bridgestone Sports Co., Ltd. | Golf ball |
Also Published As
Publication number | Publication date |
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JP2002119613A (en) | 2002-04-23 |
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