Patent ID: 8389607
Filing Date: 2013-03-05
Classification: A63B

Abstract:
1. A golf ball which comprises a core and a cover, wherein the base polymer of the cover comprises a thermoplastic polyurethane elastomer, wherein the principal component of the thermoplastic polyurethane elastomer is a reaction product of an aromatic diisocyanate and polyether polyol; wherein the cover has a Shore D hardness of 40 or greater and 55 or less and comprises a benzotriazole based ultraviolet ray absorbing agent which is at least one member selected from the group consisting of 2-(2′-hydroxy-5′-methylphenyl)benzotriazole, 2-(2′-hydroxy-5′-t-butylphenyl)benzotriazole, 2-(2-hydroxy-3′-t-butyl-5′-methylphenyl)-5-chlorobenzotriazole, 2-[2-hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl]-2H-benzotriazole, and 2-(5-methyl-2-hydroxyphenyl)benzotriazole, a hindered amine light stabilizer, a hindered phenol heat resistance stabilizer, and titanium oxide; wherein, provided that the molar concentration of the benzotriazole based ultraviolet ray absorbing agent is defined as A; the molar concentration of the hindered amine light stabilizer is defined as B; and the molar concentration of the hindered phenol heat resistance stabilizer is defined as C, the molar ratio (B/A) is 0.01 or greater and 0.5 or less, and the molar ratio [(B+C)/A] is 0.1 or greater and 1.5 or less, and wherein said golf ball has reduced weathering color change such that a ΔE derived from a weather resistance test in accordance with JIS D0205 for 24 hours is 5 or less and a ΔE derived from a weather resistance test in accordance with JIS D0205 for 120 hours is 8 or less, ΔE being calculated by the following formula in which the indices L*, a*, and b* as defined in the CIELAB color coordinate system were measured at the same measurement point prior to the weather resistance test, following the weather resistance test for 24 hrs, and following the weather resistance test for 120 hrs, and the difference of each of the indices ΔL, Δa, and Δb before and after the treatment was calculated.