POLYMERS FOR CONTACT LENSES

摘要

The present invention relates to a polyurethane polymer composition comprising polyethyleneglycol dialkyl ether. There is also provided a process for preparing a polyurethane. The invention also relates to a process for preparing a polyurethane xerogel in the form of a molded article, said process comprising the steps of: i. preparing a mixture of a. at least one polyethylene glycol or at least one polyol of formula (I), wherein at least three Of X1, X2, X3, X4 and X5 are each independently an OH-terminated group, and the remainder of X1, X2, X3, X4 and X5 are each independently H or absent, and Z is a central linking unit, a. at least one di- or poly-isocyanate, b. optionally at least one OH-terminated chain extender, and c. at least one polyethyleneglycol dialkyl ether; ii. dispensing the reaction mixture formed in step i) into a mold; iii. allowing the reaction mixture to react and cure; iv. removing the molded article from the mold; and v. hydrating the molded article.