| 摘要 |
1383422 Golf balls DUNLOP Ltd 15 May 1973 [25 May 1972] 24663/72 Addition to 1087566 Heading A6D [Also in Division C3] A golf ball comprises a thread-wound core and a cover formed of a blend of two copolymers, the first being a copolymer of a mono-olefine and an unsaturated mono- or dicanboxylic acid and the second of ethylene and vinyl acetate. The second is preferably present in an amount from 5-30% by weight and contains from 10-40% by weight of vinyl acetate and the first preferably contains ethylene. The unsaturated carboxylic acid may be methacrylic acid or acrylic acid and the first copolymer may additionally contain a vinyl alkanoic ester, an alkyl acrylate or an alkyl methacrylate monomer. The first copolymer may contain thermolabile cross-linkages formed by the addition of a metal salt of the unsaturated carboxylic acid e.g. a sodium or zinc salt or by the addition of an inorganic or organic metal cross-linking agent whose metal forms ionic bonds with the carboxyl group, example being acetates of sodium or potassium or oxides of calcium, magnesium, or zinc. Fillers e.g. of zinc or magnesium oxide may also be incorporated up to 20% by weight of the combined first and second copolymers. |
