US2013324321A1PendingUtilityA1

Golf ball

49
Assignee: DUNLOP SPORTS CO LTDPriority: Jun 1, 2012Filed: May 31, 2013Published: Dec 5, 2013
Est. expiryJun 1, 2032(~5.8 yrs left)· nominal 20-yr term from priority
Inventors:Takahiro SajimaHirotaka Nakamura
A63B 37/00922A63B 37/0038A63B 37/00622A63B 37/0063A63B 37/0003A63B 37/0076A63B 37/0051A63B 37/0044A63B 37/0032A63B 37/0031A63B 37/00A63B 37/0054A63B 37/06A63B 37/0092
49
PatentIndex Score
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Cited by
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References
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Claims

Abstract

A golf ball 2 includes a spherical core 4 and a cover 6 covering the core 4 . The cover 6 includes an inner cover 8 and an outer cover 10 positioned outside the inner cover 8 . When distances (%) from a central point of the core 4 to nine points and hardnesses at the nine points, which nine points are obtained by dividing a region from the central point to a surface of the core 4 at intervals of 12.5% of a radius of the core 4 , are plotted in a graph, R 2 of a linear approximation curve obtained by a least-square method is 0.95 or greater. A hardness of an innermost layer of the cover 6 is greater than a surface hardness of the core 4 . Preferably, the core is obtained by a rubber composition being crosslinked. The rubber composition includes an acid and/or a salt (d).

Claims

exact text as granted — not AI-modified
What is claimed is: 
     
         1 . A golf ball comprising a spherical core and a cover covering the core and including two or more layers, 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, and   a JIS-C hardness Hi of an innermost layer of the cover is greater than a JIS-C hardness Hs at the surface of the core.   
     
     
         2 . 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. 
     
     
         3 . 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 but equal to or less than 5. 
     
     
         4 . The golf ball according to  claim 1 , wherein a difference (Ho−Hi) between a JIS-C hardness Ho of an outermost layer of the cover and the JIS-C hardness Hi of the innermost layer of the cover is equal to or greater than 2 but equal to or less than 10. 
     
     
         5 . 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; or 
 (b2) a metal salt of an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms. 
   
     
     
         6 . The golf ball according to  claim 5 , 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). 
     
     
         7 . The golf ball according to  claim 5 , wherein the acid and/or the salt (d) is a carboxylic acid and/or a salt thereof (d1). 
     
     
         8 . The golf ball according to  claim 7 , 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. 
     
     
         9 . The golf ball according to  claim 7 , wherein the carboxylic acid and/or the salt thereof (d1) is a fatty acid and/or a salt thereof. 
     
     
         10 . The golf ball according to  claim 7 , wherein the carboxylic acid and/or the salt thereof (d1) is a zinc salt of a carboxylic acid. 
     
     
         11 . A golf ball comprising a spherical core and a cover covering the core and including two or more layers, 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, and   a JIS-C hardness Hi of an innermost layer of the cover is equal to or less than a JIS-C hardness Hs at the surface of the core.   
     
     
         12 . The golf ball according to  claim 11 , 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. 
     
     
         13 . The golf ball according to  claim 11 , wherein a difference (Hs−Hi) between the hardness Hs and the hardness Hi is equal to or greater than 1 but equal to or less than 20. 
     
     
         14 . The golf ball according to  claim 11 , wherein a difference (Ho−Hi) between a JIS-C hardness Ho of an outermost layer of the cover and the JIS-C hardness Hi of the innermost layer of the cover is equal to or greater than 5 but equal to or less than 30. 
     
     
         15 . The golf ball according to  claim 11 , 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; or 
 (b2) a metal salt of an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms. 
   
     
     
         16 . The golf ball according to  claim 15 , 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). 
     
     
         17 . The golf ball according to  claim 15 , wherein the acid and/or the salt (d) is a carboxylic acid and/or a salt thereof (d1). 
     
     
         18 . The golf ball according to  claim 17 , 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. 
     
     
         19 . The golf ball according to  claim 17 , wherein the carboxylic acid and/or the salt thereof (d1) is a fatty acid and/or a salt thereof. 
     
     
         20 . The golf ball according to  claim 17 , wherein the carboxylic acid and/or the salt thereof (d1) is a zinc salt of a carboxylic acid.

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