| 摘要 |
1,131,321. Table tennis balls. DUNLOP CO. Ltd. 6 Oct., 1965 [14 Oct., 1964: 15 May, 1965], Nos. 41826/64 and 20632/65. Heading A6D. [Also in Division C3] Table tennis balls are made from rigid thermoplastic material having a burning rate (ASTM D-635-63) of not more than 5 inches per minute, a power factor at 10<SP>6</SP> cycles (ASTM D-150-59T) of not more than 0.05, an Izod impact strength on a ¢ inch by ¢ inch notched bar (ASTM D-256-56) of at least 2.5 ft. lb./in. of notch and a water absorption less than 0.9% in 24 hour for a thickness of 0.125 inch (ASTM D-570). Specified are PVC, acrylonitrile - butadiene - styrene copolymers, polypropylene, highly crystalline ethylene-propylene copolymers, high density polyethylene, polycarbonates, polyamides and high molecular weight diphenylol propane-epichlorohydrin copolymers having no free iponide groups. The manufacture of table tennis balls is as described in Specification 1,131,323. |
