To provide a rubber thread winding golf ball which solves the problem in production of the urethane cover of the rubber thread winding golf ball having the polyurethane cover, has a good ball hitting feel like that of a Balata cover and is large in a spin quantity and is liable to stop even in a shot under a rainy weather.
The polyurethane cover described above may be compounded at a low temperature and may be manufactured without gelatinization even in the case of an isocyanate group terminated urethane prepolymer having an MDI residue of high reactivity by using a hardener containing a polyamine mixture expressed by general formula (1). Since the curing reaction may be effected at a low temperature, the rubber thread winding golf ball which is free of the deterioration in the rubber thread layer and has excellent repulsiveness and ball hitting feel is obtained.
SASAKI TAKASHI
MORIYAMA KEIJI
ISOGAWA KAZUHIKO
