GROSS CONTROL OF THE HARTH SEGMENTS IN POLYURY MANAGEMENT

摘要

Improved methods for forming urethane elastomers and corresponding urethane prepolymers are disclosed wherein diisocyanate and a low molecular weight diol are simultaneously mixed and reacted to form a hard segment which is subsequently reacted with a long chain diol to form the elastomer. Aliphatic diisocyanates are particularly desirable for the manufacture of contact lenses from the urethane prepolymers of this invention.