Site News  |   Monitor Keywords  |   Monitor Archive  |   Organizer  |   Account Info  |

Golf equipment formed from castable formulations with resiliency comparable to ionomer resins

Golf equipment formed from castable formulations with resiliency comparable to ionomer resins description/claims

The invention relates to compositions including castable formulations that have improved resiliency and coefficient of restitution. In addition, the invention is directed to golf equipment formed from the castable formulations. In particular, the present invention is directed to castable polyurea compositions that have comparable coefficient of restitution to conventional ionomers.

Golf balls are formed from a variety of compositions, which provides a golf ball manufacturer the ability to alter feel and aerodynamic characteristics of a particular ball. For example, golf ball covers formed from balata allow a highly skilled golfer to achieve spin rates sufficient to more precisely control ball direction and distance, particularly on shorter shots. Balata covered golf balls are easily damaged, however, which discourages the average golfer from using such balls. To remedy this durability issue, manufacturers typically use ionomer resin as a cover material. However, while ionomer resin covered golf balls possess virtually cut-proof covers, the spin and feel are inferior compared to balata covered balls.

Polyurethanes and polyureas have also been recognized as useful materials for golf ball covers since the resulting golf balls are durable like ionomer resin, but have the soft feel of a balata covered golf ball. U.S. Pat. No. 4,123,061 teaches a golf ball made from a polyurethane prepolymer formed of polyether with diisocyanate that is cured with either a polyol or an amine-type curing agent. In addition, U.S. Pat. No. 5,334,673 discloses the use of two categories of polyurethane available on the market, i.e., thermoset and thermoplastic polyurethanes, for forming golf ball covers and, in particular, thermoset polyurethane covered golf balls made from a composition of polyurethane prepolymer and a slow-reacting amine curing agent, and/or a difunctional glycol. U.S. Pat. No. 5,484,870 discloses a polyurea composition comprising the reaction product of an organic diisocyanate and an organic amine, each having at least two functional groups. Once these two ingredients are combined, the reaction rate is very fast and, thus, the ability to vary the physical properties of the composition is limited.

While polyurethane and polyurea covered golf balls are softer than ionomer resin covered golf balls, such balls do not fully match ionomer resin golf balls with respect to resilience or the rebound (a function of the initial velocity of a golf ball after impact with a golf club) of the golf ball cover. Furthermore, because the polyurethanes and polyureas used to make the covers of such golf balls generally contain an aromatic component, e.g., an aromatic diisocyanate, polyol, or polyamine, they are susceptible to discoloration upon exposure to light, particularly ultraviolet (UV) light. To inhibit or slow down the discoloration, light and UV stabilizers, e.g., Tinuvin 770, 765, and 328, are added to these aromatic polymeric materials. In addition, to further ensure that the covers formed from aromatic polyurethanes do not appear discolored, the covers are painted with white paint and then covered with a clear coat to maintain the white color of the golf ball. However, the application of a uniform white pigmented coat to the dimpled surface of the golf ball is a difficult process that adds time and costs to the manufacture of a golf ball.

Therefore, there remains a continuing need for golf equipment and, in particular, golf balls having components formed from materials that provide at least comparable resilience to that of ionomer resins without adversely affecting overall performance characteristics of the golf balls. In addition, it would be advantageous to provide a composition that combines the cut and scratch resistance with improved resistance to discoloration that are suitable for forming golf ball components and other golf-related equipment.

The present invention is directed to a golf ball including a core and a cover, wherein at least a portion of the golf ball is formed from a composition including: a prepolymer formed from the reaction product of an isocyanate-containing component and an isocyanate-reactive component, wherein the isocyanate-containing component is trifunctional and the isocyanate-reactive component includes a secondary diamine; and a curing agent including 3,3′-dimethyl-4,4′-bis(sec-butylamino)-dicyclohexylmethane. In one embodiment, the composition consists essentially of linkages having the general formulae:

wherein x is the chain length and is about 1 or greater, and wherein R and R1 are alkyl groups including from about 1 to about 20 carbon atoms, a phenyl group, a cyclic group, or mixture thereof.

In this aspect of the invention, the secondary diamine may have a molecular weight of about 200 to about 3000. In one embodiment, the secondary diamine has a molecular weight of about 1800 to about 2200. The isocyanate-containing component may include about 15 percent to about 25 percent NCO groups. In one embodiment, the isocyanate-containing component includes about 20 percent to about 28 percent NCO groups.

The present invention also relates to a golf ball including: a core; a layer disposed about the core to create an inner ball; and a cover cast onto the inner ball, wherein at least a portion of the ball is formed from a composition including: a prepolymer formed from the reaction product of at least one trifunctional isocyanate-containing component and at least one amine-terminated isocyanate-reactive component, wherein the prepolymer has NCO content of about 10 percent to about 20 percent; and at least one amine-terminated curing agent.

In one embodiment, the amine-terminated curing agent includes 3,3′-dimethyl-4,4′-bis(sec-butylamino)-dicyclohexylmethane. In another embodiment, the amine-terminated isocyanate-reactive component includes a secondary diamine, a secondary triamine, or a combination thereof. In another embodiment, the prepolymer has NCO content of about 12 percent to about 16 percent. In yet another embodiment, the amine-terminated curing agent includes 3,3′-dimethyl-4,4′-bis(sec-butylamino)-dicyclohexylmethane, and wherein the amine-terminated isocyanate-reactive component includes a secondary diamine, a secondary triamine, or a combination thereof.

While the compositions of the invention may be incorporated into any portion of the golf ball, in one embodiment, the cover includes the composition. In another embodiment, an intermediate layer of the ball is formed of the composition. When formed into a solid sphere, however, the composition has a compression of about 160 to about 200 atti or 170 to 190 atti when formed into a solid sphere. The composition may also have a coefficient of restitution of about 0.77 or greater when formed into a solid sphere.

The present invention also relates to a golf ball including: a core; and a cover formed of a castable polyurea material consisting essentially of linkages having the general formulae:

• Provisional Patent
• Utility Patent

• What Is a Patent?
• What Is a Trademark or Servicemark?
• What Is a Copyright?
• Patent Laws