| 摘要 |
A game ball having a softer core and abrasion resistant cover is particularly well suited for play on hard pavements and cement in inner city areas. The ball has a polyurethane foam core formed from a mixture of 100 parts polyol and 33-40 parts isocyanate. The core has a compression of 0.06-0.07 inches when subjected to a force of 10 lbs. and a coefficient of restitution at 88 feet per second of less than 0.45, and preferably 0.30-0.40. A molded polyvinyl chloride plastisol cover is formed over the core, resulting in a game ball for which the ratio of the coefficient of restitution of the ball to the coefficient of restitution of the core is in the range of about 0.90-0.99. The cover preferably is a durable molded cover having a Shore A hardness of about 60-70 and a tensile strength of about 1,400-1,800 psi. The ball of the invention has restricted flight characteristics and is particularly well suited for use on smaller ball fields.
|
