Golf Ball Cores
“Golf balls generally include a core and at least one cover layer surrounding the core. Material characteristics of the compositions used in the core, and the resulting mechanical properties of the core, are important in determining the golf ball's performance. For example, the core's composition affects the golf ball's coefficient of restitution (C.O.R.), i.e., the ratio of the ball's post-impact speed to pre-impact speed. The C.O.R. affects the ball's speed and distance when hit. The core's composition also affects the ball's compression, i.e., a measure of the deflection of the ball when a standard force is applied to the ball. Cores exhibiting low compression provide for improved ball feel, but also tend to exhibit reduced C.O.R., which results in reduced ball flight distance.”
“Golf ball cores generally incorporate polybutadiene rubbers cross-linked with sulfur compounds, or peroxides, and a metal salt of an acrylate, such as zinc diacrylate ("ZDA") or zinc dimethacrylate ("ZDMA"). These compositions provide for improved properties; however, despite years of continual improvements in rubber core formulations, ideal properties have not yet been achieved for golf balls. Increasing the loading levels of sulfur compounds, peroxides, or acrylate metal salts in the polybutadiene rubber used for a core composition is known to increase C.O.R. However, this also leads to increased compression, resulting in poorer ball feel and increased driver spin rate, which results in reduced flight distance. This relationship between C.O.R. and compression can be adjusted only to a limited extent using known accelerators, cross-linking agents, and co-cross-linking agents.”
“In view of the above, it is apparent that improved golf ball cores that result in golf balls having optimal performance, e.g., spin rate value, hit-feel characteristics, and durability, while demonstrating ease of manufacture, as well as methods for making these cores are needed.”
(Kim, Jeon and Okamoto, US Patent 7,819,761; 10/26/2010)
Applications
Golf Balls
Sports
Recent US Patents
10/26/2010
7,819,761
Golf ball having cross-core hardness differential and method for making it
Kim, Jeon and Okamoto of Taylor Made Golf Company, California have developed a golf ball with a center point having a specific hardness value and an outer surface having a different hardness. (RDC 2/14/2011)
7,819,760
Golf ball layer having reduced surface hardness and method of making same
Sullivan, Binette and Comeau of Acushnet has developed a golf ball with a core consisting of a thermoset rubber with a geometric center and a treated outer surface. The surface is softened with a fatty acid salt plasticizer composition such that the second hardness is greater than the first hardness to define a negative hardness gradient. (RDC 2/14/2011)
10/26/2010
7,806,783
Golf ball with large inner core
Ladd and Sullivan of Acushnet, Massachusetts have developed a golf ball with having high resiliency, a low spin, and a high rotational momentum imparted by a large soft interior inner core and at least one weight shifted outer layer without any fillers. (RDC 12/19/2010)
9/28/2010
7,803,069
Negative hardness gradient inner core for dual core golf ball
Bulpett et al of Acushnet Company has developed a golf ball with an inner core outer surface with a hardness lower than that of the geometric center to define a negative hardness gradient. The hardness of the outer surface of the intermediate layer is the same as the hardness of the inner surface to define a zero hardness gradient. (RDC 12/7/2010)