US2013316850A1PendingUtilityA1

Golf ball

48
Assignee: DUNLOP SPORTS CO LTDPriority: May 25, 2012Filed: Mar 14, 2013Published: Nov 28, 2013
Est. expiryMay 25, 2032(~5.8 yrs left)· nominal 20-yr term from priority
Inventors:Hidetaka InoueTakahiro Sajima
A63B 37/0076A63B 37/0054A63B 37/0043A63B 37/0063A63B 37/0092A63B 37/0031A63B 37/06A63B 37/00
48
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Claims

Abstract

A golf ball 2 includes a core 4 , an inner cover 8 , a mid cover 10 , and an outer cover 12 . Nine points are determined by dividing a region from a central point of the core 4 to a surface of the core 4 at intervals of 12.5% of a radius of the core 4 . When distances (%) from the central point to the nine points and hardnesses at the nine points are plotted in a graph, R 2 of a linear approximation curve obtained by a least-square method is equal to or greater than 0.95. A hardness Hi of the inner cover 8 is greater than a hardness Hs at the surface of the core 4 . A hardness Ho of the outer cover 12 is greater than the hardness Hi. A difference (Hi−Hs) is 1 or greater. A difference (Ho−Hi) is 5 or greater but 30 or less.

Claims

exact text as granted — not AI-modified
What is claimed is: 
     
         1 . A golf ball comprising a core, an inner cover positioned outside the core, a mid cover positioned outside the inner cover, and an outer cover positioned outside the mid cover, wherein
 when distances (%) from a central point of the core to nine points and JIS-C hardnesses at the nine points, which nine points are obtained by dividing a region from the central point of the core to a surface of the core at intervals of 12.5% of a radius of the core, are plotted in a graph, R 2  of a linear approximation curve obtained by a least-square method is equal to or greater than 0.95,   a JIS-C hardness Hi of the inner cover is greater than a JIS-C hardness Hs at the surface of the core, and   a JIS-C hardness Ho of the outer cover is greater than the hardness Hi.   
     
     
         2 . The golf ball according to  claim 1 , wherein a difference (Hi−Hs) between the hardness Hi and the hardness Hs is equal to or greater than 1. 
     
     
         3 . The golf ball according to  claim 1 , wherein a difference (Ho−Hi) between the hardness Ho and the hardness Hi is equal to or greater than 5 but equal to or less than 30. 
     
     
         4 . The golf ball according to  claim 1 , wherein a difference (Hs−H(0)) between the hardness Hs and a JIS-C hardness H(0) at the central point of the core is equal to or greater than 15. 
     
     
         5 . The golf ball according to  claim 1 , wherein
 a thickness Ti of the inner cover is equal to or less than 1.2 mm,   a thickness Tm of the mid cover is equal to or less than 1.2 mm, and   a thickness To of the outer cover is equal to or less than 1.2 mm.   
     
     
         6 . The golf ball according to  claim 1 , wherein a sum (Ti+Tm+To) of a thickness Ti of the inner cover, a thickness Tm of the mid cover, and a thickness To of the outer cover is equal to or less than 2.5 mm. 
     
     
         7 . The golf ball according to  claim 1 , wherein
 the hardness Ho is greater than a JIS-C hardness Hm of the mid cover, and   a difference (Ho−Hm) between the hardness Ho and the hardness Hm is equal to or greater than 2.   
     
     
         8 . The golf ball according to  claim 1 , wherein
 the core is formed by a rubber composition being crosslinked,   the rubber composition includes:
 (a) a base rubber; 
 (b) a co-crosslinking agent; 
 (c) a crosslinking initiator; and 
 (d) an acid and/or a salt, and 
   the co-crosslinking agent (b) is:
 (b1) an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms; and/or 
 (b2) a metal salt of an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms. 
   
     
     
         9 . The golf ball according to  claim 8 , wherein an amount of the acid and/or the salt (d) is equal to or greater than 0.5 parts by weight but equal to or less than 40 parts by weight, per 100 parts by weight of the base rubber (a). 
     
     
         10 . The golf ball according to  claim 8 , wherein the acid and/or the salt (d) is a carboxylic acid and/or a salt thereof (d1). 
     
     
         11 . The golf ball according to  claim 10 , wherein the carboxylic acid and/or the salt thereof (d1) is a fatty acid and/or a salt thereof. 
     
     
         12 . The golf ball according to  claim 10 , wherein a carbon number of a carboxylic acid component of the carboxylic acid and/or the salt thereof (d1) is equal to or greater than 1 but equal to or less than 30. 
     
     
         13 . The golf ball according to  claim 10 , wherein the carboxylic acid and/or the salt thereof (d1) is a zinc salt of a carboxylic acid. 
     
     
         14 . The golf ball according to  claim 13 , wherein the zinc salt of the carboxylic acid is one or more members selected from the group consisting of zinc octoate, zinc laurate, zinc myristate, and zinc stearate. 
     
     
         15 . The golf ball according to  claim 8 , wherein the rubber composition includes 15 parts by weight or greater but 50 parts by weight or less of the co-crosslinking agent (b) per 100 parts by weight of the base rubber (a). 
     
     
         16 . The golf ball according to  claim 8 , wherein the rubber composition includes 0.2 parts by weight or greater but 5.0 parts by weight or less of the crosslinking initiator (c) per 100 parts by weight of the base rubber (a). 
     
     
         17 . The golf ball according to  claim 8 , wherein the rubber composition further includes an organic sulfur compound (e). 
     
     
         18 . The golf ball according to  claim 17 , wherein the organic sulfur compound (e) is at least one member selected from the group consisting of thiophenols, diphenyl disulfides, thionaphthols, thiuram disulfides, and metal salts thereof. 
     
     
         19 . The golf ball according to  claim 17 , wherein the rubber composition includes 0.05 parts by weight or greater but 5 parts by weight or less of the organic sulfur compound (e) per 100 parts by weight of the base rubber (a). 
     
     
         20 . The golf ball according to  claim 8 , wherein
 the rubber composition includes the α,β-unsaturated carboxylic acid (b1), and   the rubber composition further includes a metal compound (f).   
     
     
         21 . A golf ball comprising a core, a first cover positioned outside the core, a second cover positioned outside the first cover, a third cover positioned outside the second cover, and a fourth cover positioned outside the third cover, wherein
 when distances (%) from a central point of the core to nine points and JIS-C hardnesses at the nine points, which nine points are obtained by dividing a region from the central point of the core to a surface of the core at intervals of 12.5% of a radius of the core, are plotted in a graph, R 2  of a linear approximation curve obtained by a least-square method is equal to or greater than 0.95,   a JIS-C hardness H1 of the first cover is greater than a JIS-C hardness Hs at the surface of the core, and   a JIS-C hardness H4 of the fourth cover is greater than the JIS-C hardness H1 of the first cover.   
     
     
         22 . The golf ball according to  claim 21 , wherein a difference (H1−Hs) between the hardness H1 and the hardness Hs is equal to or greater than 1.0. 
     
     
         23 . The golf ball according to  claim 21 , wherein a difference (H4−H1) between the hardness H4 and the hardness H1 is equal to or greater than 3 but equal to or less than 30. 
     
     
         24 . The golf ball according to  claim 21 , wherein a difference (Hs−H(0)) between the hardness Hs and a JIS-C hardness H(0) at the central point of the core is equal to or greater than 15. 
     
     
         25 . The golf ball according to  claim 21 , wherein
 a thickness T1 of the first cover is equal to or less than 1.8 mm,   a thickness T2 of the second cover is equal to or less than 1.8 mm,   a thickness T3 of the third cover is equal to or less than 1.8 mm, and   a thickness T4 of the fourth cover is equal to or less than 1.8 mm.   
     
     
         26 . The golf ball according to  claim 21 , wherein a sum (T1+T2+T3+T4) of a thickness T1 of the first cover, a thickness T2 of the second cover, a thickness T3 of the third cover, and a thickness T4 of the fourth cover is equal to or less than 6.0 mm. 
     
     
         27 . The golf ball according to  claim 21 , wherein
 the core is formed by a rubber composition being crosslinked,   the rubber composition includes:
 (a) a base rubber; 
 (b) a co-crosslinking agent; 
 (c) a crosslinking initiator; and 
 (d) an acid and/or a salt, and 
   the co-crosslinking agent (b) is:
 (b1) an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms; and/or 
 (b2) a metal salt of an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms. 
   
     
     
         28 . The golf ball according to  claim 27 , wherein an amount of the acid and/or the salt (d) is equal to or greater than 0.5 parts by weight but equal to or less than 40 parts by weight, per 100 parts by weight of the base rubber (a). 
     
     
         29 . The golf ball according to  claim 27 , wherein the acid and/or the salt (d) is a carboxylic acid and/or a salt thereof (d1). 
     
     
         30 . The golf ball according to  claim 29 , wherein the carboxylic acid and/or the salt thereof (d1) is a fatty acid and/or a salt thereof. 
     
     
         31 . The golf ball according to  claim 29 , wherein a carbon number of a carboxylic acid component of the carboxylic acid and/or the salt thereof (d1) is equal to or greater than 1 but equal to or less than 30. 
     
     
         32 . The golf ball according to  claim 29 , wherein the carboxylic acid and/or the salt thereof (d1) is a zinc salt of a carboxylic acid. 
     
     
         33 . The golf ball according to  claim 32 , wherein the zinc salt of the carboxylic acid is one or more members selected from the group consisting of zinc octoate, zinc laurate, zinc myristate, and zinc stearate. 
     
     
         34 . The golf ball according to  claim 27 , wherein the rubber composition includes 15 parts by weight or greater but 50 parts by weight or less of the co-crosslinking agent (b) per 100 parts by weight of the base rubber (a). 
     
     
         35 . The golf ball according to  claim 27 , wherein the rubber composition includes 0.2 parts by weight or greater but 5.0 parts by weight or less of the crosslinking initiator (c) per 100 parts by weight of the base rubber (a). 
     
     
         36 . The golf ball according to  claim 27 , wherein the rubber composition further includes an organic sulfur compound (e). 
     
     
         37 . The golf ball according to  claim 36 , wherein the organic sulfur compound (e) is at least one member selected from the group consisting of thiophenols, diphenyl disulfides, thionaphthols, thiuram disulfides, and metal salts thereof. 
     
     
         38 . The golf ball according to  claim 36 , wherein the rubber composition includes 0.05 parts by weight or greater but 5 parts by weight or less of the organic sulfur compound (e) per 100 parts by weight of the base rubber (a). 
     
     
         39 . The golf ball according to  claim 27 , wherein
 the rubber composition includes the α,β-unsaturated carboxylic acid (b1), and   the rubber composition further includes a metal compound (f).   
     
     
         40 . The golf ball according to  claim 21 , wherein
 a hardness H2 of the second cover is greater than the hardness H1,   a hardness H3 of the third cover is greater than the hardness H2, and   the hardness H4 is greater than the hardness H3.   
     
     
         41 . The golf ball according to  claim 40 , wherein a difference (H2−H1) between the hardness H2 and the hardness H1 is equal to or greater than 2. 
     
     
         42 . The golf ball according to  claim 40 , wherein a difference (H3−H2) between the hardness H3 and the hardness H2 is equal to or greater than 2. 
     
     
         43 . The golf ball according to  claim 40 , wherein a difference (H4−H3) between the hardness H4 and the hardness H3 is equal to or greater than 2. 
     
     
         44 . A golf ball comprising a core, an inner cover positioned outside the core, a mid cover positioned outside the inner cover, and an outer cover positioned outside the mid cover, wherein
 when distances (%) from a central point of the core to nine points and JIS-C hardnesses at the nine points, which nine points are obtained by dividing a region from the central point of the core to a surface of the core at intervals of 12.5% of a radius of the core, are plotted in a graph, R 2  of a linear approximation curve obtained by a least-square method is equal to or greater than 0.95,   a JIS-C hardness Hs at the surface of the core is greater than a JIS-C hardness Hi of the inner cover, and   a JIS-C hardness Ho of the outer cover is greater than the JIS-C hardness Hi of the inner cover.   
     
     
         45 . The golf ball according to  claim 44 , wherein a difference (Hs−Hi) between the hardness Hs and the hardness Hi is equal to or greater than 1. 
     
     
         46 . The golf ball according to  claim 44 , wherein a difference (Ho−Hi) between the hardness Ho and the hardness Hi is equal to or greater than 5 but equal to or less than 30. 
     
     
         47 . The golf ball according to  claim 44 , wherein a difference (Hs−H(0)) between the hardness Hs and a JIS-C hardness H(0) at the central point of the core is equal to or greater than 15. 
     
     
         48 . The golf ball according to  claim 44 , wherein
 a thickness Ti of the inner cover is equal to or less than 1.2 mm,   a thickness Tm of the mid cover is equal to or less than 1.2 mm, and   a thickness To of the outer cover is equal to or less than 1.2 mm.   
     
     
         49 . The golf ball according to  claim 44 , wherein a sum (Ti+Tm+To) of a thickness Ti of the inner cover, a thickness Tm of the mid cover, and a thickness To of the outer cover is equal to or less than 2.5 mm. 
     
     
         50 . The golf ball according to  claim 44 , wherein the JIS-C hardness Ho of the outer cover is greater than a JIS-C hardness Hm of the mid cover. 
     
     
         51 . The golf ball according to  claim 50 , wherein a difference (Ho−Hm) between the hardness Ho and the hardness Hm is equal to or greater than 2. 
     
     
         52 . The golf ball according to  claim 44 , wherein
 the core is formed by a rubber composition being crosslinked,   the rubber composition includes:
 (a) a base rubber; 
 (b) a co-crosslinking agent; 
 (c) a crosslinking initiator; and 
 (d) an acid and/or a salt, and 
   the co-crosslinking agent (b) is:
 (b1) an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms; and/or 
 (b2) a metal salt of an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms. 
   
     
     
         53 . The golf ball according to  claim 52 , wherein an amount of the acid and/or the salt (d) is equal to or greater than 0.5 parts by weight but equal to or less than 40 parts by weight, per 100 parts by weight of the base rubber (a). 
     
     
         54 . The golf ball according to  claim 52 , wherein the acid and/or the salt (d) is a carboxylic acid and/or a salt thereof (d1). 
     
     
         55 . The golf ball according to  claim 54 , wherein a carbon number of a carboxylic acid component of the carboxylic acid and/or the salt thereof (d1) is equal to or greater than 1 but equal to or less than 30. 
     
     
         56 . The golf ball according to  claim 54 , wherein the carboxylic acid and/or the salt thereof (d1) is a fatty acid and/or a salt thereof. 
     
     
         57 . The golf ball according to  claim 52 , wherein the rubber composition includes 15 parts by weight or greater but 50 parts by weight or less of the co-crosslinking agent (b) per 100 parts by weight of the base rubber (a). 
     
     
         58 . The golf ball according to  claim 52 , wherein the rubber composition includes 0.2 parts by weight or greater but 5.0 parts by weight or less of the crosslinking initiator (c) per 100 parts by weight of the base rubber (a). 
     
     
         59 . The golf ball according to  claim 52 , wherein the rubber composition further includes an organic sulfur compound (e). 
     
     
         60 . The golf ball according to  claim 59 , wherein the organic sulfur compound (e) is at least one member selected from the group consisting of thiophenols, diphenyl disulfides, thionaphthols, thiuram disulfides, and metal salts thereof. 
     
     
         61 . The golf ball according to  claim 59 , wherein the rubber composition includes 0.05 parts by weight or greater but 5 parts by weight or less of the organic sulfur compound (e) per 100 parts by weight of the base rubber (a). 
     
     
         62 . The golf ball according to  claim 52 , wherein
 the rubber composition includes the α,β-unsaturated carboxylic acid (b1), and   the rubber composition further includes a metal compound (f).   
     
     
         63 . The golf ball according to  claim 52 , wherein the acid and/or the salt (d) is a zinc salt of a carboxylic acid. 
     
     
         64 . The golf ball according to  claim 63 , wherein the zinc salt of the carboxylic acid is one or more members selected from the group consisting of zinc octoate, zinc laurate, zinc myristate, and zinc stearate. 
     
     
         65 . A golf ball comprising a core, an inner cover positioned outside the core, a first mid cover positioned outside the inner cover, a second mid cover positioned outside the first mid cover, and an outer cover positioned outside the second mid cover, wherein
 when distances (%) from a central point of the core to nine points and JIS-C hardnesses at the nine points, which nine points are obtained by dividing a region from the central point of the core to a surface of the core at intervals of 12.5% of a radius of the core, are plotted in a graph, R 2  of a linear approximation curve obtained by a least-square method is equal to or greater than 0.95,   a JIS-C hardness Hs at the surface of the core is greater than a JIS-C hardness Hi of the inner cover, and   a JIS-C hardness Ho of the outer cover is greater than the JIS-C hardness Hi of the inner cover.   
     
     
         66 . The golf ball according to  claim 65 , wherein a difference (Hs−Hi) between the hardness Hs and the hardness Hi is equal to or greater than 1. 
     
     
         67 . The golf ball according to  claim 65 , wherein a difference (Ho−Hi) between the hardness Ho and the hardness Hi is equal to or greater than 5 but equal to or less than 30. 
     
     
         68 . The golf ball according to  claim 65 , wherein the hardness Hs is greater than a JIS-C hardness H(0) at the central point of the core. 
     
     
         69 . The golf ball according to  claim 68 , wherein a difference (Hs−H(0)) between the hardness Hs and the hardness H(0) is equal to or greater than 15. 
     
     
         70 . The golf ball according to  claim 65 , wherein
 a thickness Ti of the inner cover is equal to or less than 1.8 mm,   a thickness Tm1 of the first mid cover is equal to or less than 1.8 mm,   a thickness Tm2 of the second mid cover is equal to or less than 1.8 mm, and   a thickness To of the outer cover is equal to or less than 1.8 mm.   
     
     
         71 . The golf ball according to  claim 70 , wherein a sum (Ti+Tm1+Tm2+To) of the thickness Ti of the inner cover, the thickness Tm1 of the first mid cover, the thickness Tm2 of the second mid cover, and the thickness To of the outer cover is equal to or less than 6.0 mm. 
     
     
         72 . The golf ball according to  claim 65 , wherein
 the core is formed by a rubber composition being crosslinked,   the rubber composition includes:
 (a) a base rubber; 
 (b) a co-crosslinking agent; 
 (c) a crosslinking initiator; and 
 (d) an acid and/or a salt, and 
   the co-crosslinking agent (b) is:
 (b1) an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms; and/or 
 (b2) a metal salt of an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms. 
   
     
     
         73 . The golf ball according to  claim 72 , wherein an amount of the acid and/or the salt (d) is equal to or greater than 1 parts by weight but less than 40 parts by weight, per 100 parts by weight of the base rubber (a). 
     
     
         74 . The golf ball according to  claim 72 , wherein the acid and/or the salt (d) is a carboxylic acid and/or a salt thereof (d1). 
     
     
         75 . The golf ball according to  claim 74 , wherein a carbon number of a carboxylic acid component of the carboxylic acid and/or the salt thereof (d1) is equal to or greater than 1 but equal to or less than 30. 
     
     
         76 . The golf ball according to  claim 74 , wherein the carboxylic acid and/or the salt thereof (d1) is a fatty acid and/or a salt thereof. 
     
     
         77 . The golf ball according to  claim 72 , wherein the rubber composition includes 15 parts by weight or greater but 50 parts by weight or less of the co-crosslinking agent (b) per 100 parts by weight of the base rubber (a). 
     
     
         78 . The golf ball according to  claim 72 , wherein the rubber composition includes 0.2 parts by weight or greater but 5.0 parts by weight or less of the crosslinking initiator (c) per 100 parts by weight of the base rubber (a). 
     
     
         79 . The golf ball according to  claim 72 , wherein the rubber composition further includes an organic sulfur compound (e). 
     
     
         80 . The golf ball according to  claim 79 , wherein the organic sulfur compound (e) is at least one member selected from the group consisting of thiophenols, diphenyl disulfides, thionaphthols, thiuram disulfides, and metal salts thereof. 
     
     
         81 . The golf ball according to  claim 79 , wherein the rubber composition includes 0.05 parts by weight or greater but 5 parts by weight or less of the organic sulfur compound (e) per 100 parts by weight of the base rubber (a). 
     
     
         82 . The golf ball according to  claim 72 , wherein
 the rubber composition includes the α,β-unsaturated carboxylic acid (b1), and   the rubber composition further includes a metal compound (f).   
     
     
         83 . The golf ball according to  claim 72 , wherein the acid and/or the salt (d) is a zinc salt of a carboxylic acid. 
     
     
         84 . The golf ball according to  claim 83 , wherein the zinc salt of the carboxylic acid is one or more members selected from the group consisting of zinc octoate, zinc laurate, zinc myristate, and zinc stearate.

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