Golf ball

Details Golf ball Golf ball

1998-06-23

2001-11-20

Nakarani, D. S. (Department: 1773)

Games using tangible projectile

Golf

Ball

C473S365000, C473S377000, C473S378000, C528S092000

Reexamination Certificate

active

06319152

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to cover stocks for golf balls offering a good feel when hit and having improved scuff resistance. More particularly, it relates to cover stocks suitable for the manufacture of golf balls which offer a very soft feel without exhibiting a shock when hit with a driver and exhibit improved scuff resistance against iron shots without detracting from the ease of control upon approach shots.
2. Prior Art
In prior art golf balls, balata or trans-polyisoprene is often used as the cover stock. Professional and skilled golfers prefer golf balls using balata as the cover stock, because the balata cover balls are good in feel upon full shots with a driver and the ease of control (or spin susceptibility) upon approach shots.
The balata cover balls, however, have the drawback that the ball surface is marred or fluffed as a consequence of iron shots because the cover surface can be scraped by grooves across the iron club face. In addition, balata is expensive and low in productivity because of the difficulty to mold.
For overcoming these drawbacks of balata, a variety of cover stocks using thermoplastic polyurethane elastomers have been proposed (U.S. Pat. Nos. 3,395,109, 4,248,432, and 4,442,282).
Since thermoplastic polyurethane elastomers used as the cover stock are not only improved in feel and control like balata, but also inexpensive and easy to mold, these elastomers are regarded as an excellent cover stock substitute for the balata material. However, the thermoplastic polyurethane elastomers are still insufficient in scuff resistance upon iron shots. Particularly at low temperatures or in winter, there is a likelihood that the ball surface can be cracked and dimples will be scraped off by the iron club face.
There is a desire to develop a cover stock suitable for the manufacture of high performance golf balls which exhibit improved scuff resistance against iron shots without detracting from the ease of control upon approach shots, and offer a very soft feel without shocks when hit.
SUMMARY OF THE INVENTION
An object of the invention is to provide a novel and improved golf ball cover stock which offers the ease of control upon approach shots and a very soft feel without shocks, and is further improved in scuff resistance against iron shots.
In search of a golf ball cover stock which can offer a pleasant feel and is improved in controllability and scuff resistance, the inventors have found that a golf ball cover stock comprising as a main component a heated mixture of a thermoplastic polyurethane elastomer and a styrene base block copolymer is best suited for achieving the above and other objects.
More particularly, according to the invention, a heated mixture of (1) a thermoplastic polyurethane elastomer, especially a thermoplastic polyurethane elastomer having a Shore D hardness of 35 to 55 and comprising an aliphatic diisocyanate as the diisocyanate component and (2) a styrene base block copolymer having improved compatibility therewith and also serving as a binder, especially a flexible styrene base block copolymer having a JIS-A hardness of 50 to 98 is used as the main component of the golf ball cover stock. Golf balls obtained by enclosing cores with this cover stock receive an appropriate back spin rate upon approach shots and are thus easy to control. In addition, these golf balls substantially solve the problem that as a consequence of iron shots, the cover surface can be scraped by grooves across the iron club face and the ball surface is marred or fluffed. Upon full shots with a driver, the balls offer a very soft feel without a shock and without a shortage of flight distance. Therefore, the cover stock composed mainly of a heated thermoplastic polyurethane elastomer/styrene base block copolymer mixture is significantly improved in function and effect over conventional cover stocks of thermoplastic polyurethane elastomers.
Accordingly, the present invention provides a golf ball cover stock comprising as a main component a heated mixture of a thermoplastic polyurethane elastomer and a styrene base block copolymer.
Preferably, the thermoplastic polyurethane elastomer has a Shore D hardness of 35 to 55, the styrene base block copolymer has a JIS A hardness of 50 to 98, and the heated mixture has a Shore D hardness of 35 to 55. Also preferably, the heated mixture consists of 50 to 99% by weight of the thermoplastic polyurethane elastomer and 50 to 1% by weight of the styrene base block copolymer.
The preferred styrene base block copolymer has been modified with functional groups, typically carboxyl or epoxy groups so that the copolymer may have an acid value of 1 to 15 mg CH
3
ONa per gram. In one preferred embodiment, the styrene base block copolymer is a tri-block elastomer consisting of terminal polystyrene blocks and an intermediate block. The intermediate block is preferably composed of polybutadiene, polyisoprene, polyethylene/butylene or polyethylene/propylene. In another preferred embodiment, the styrene base block copolymer is a di-block elastomer consisting of one terminal block of polystyrene and another terminal block of a resin other than the polystyrene. The other terminal block is preferably composed of polybutadiene, polyisoprene, polyethylene/butylene or polyethylene/propylene. The preferred styrene base block copolymer has a styrene contents of 10 to 50% by weight.
The diusocyanate component of the preferred thermoplastic polyurethane elastomer is an aliphatic diisocyanate.


REFERENCES:
patent: 4429076 (1984-01-01), Saito et al.
patent: 5688191 (1997-11-01), Cavallaro et al.
patent: 5693711 (1997-12-01), Akiba et al.

Affiliated with

Also associated with

Rating

Golf ball does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Golf ball, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Golf ball will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2615305