| 摘要 |
A golf ball core comprises a spherical body of high water content hydrogel around which rubber filaments are wound. The spherical body is prepared by casting into a mould an aqueous solution or suspension containing 100 parts by weight of an aqueous polyvinyl alcohol solution or suspension and 5 to 40 parts by weight of a filler having a specific gravity of more than 1, cooling the cast aqueous solution or suspension to a temperature of not higher than - (minus) 10 DEG C to obtain a frozen mass, thawing the mass and one to seven additional cyclic processing steps each including the freezing and thawing steps. The aqueous solution of suspension contains more than 5 wt.% and not more than 40 wt.% of a polyvinyl alcohol having a degree of hydrolysis of not less than 95 mol % and an average polymerization degree of not less than 700. Preferably the hydrogel contains a further water-soluble organic compound, particularly a polyhydric alcohol such as ethylene glycol, propylene glycol, glycerin or D-sorbitol, in an amount of up to 30 wt.%.
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