Terpolymeres with the first of hydrogels

摘要

These terpolymers comprise from 5 - 20 by weight of a oligourethane having a double bond, a mass average is a continuation of 1200 to 3000 and the general formula: & br / (see appended drawing in bopi) & br / r being the diol used and the diisocyanate used, x being h or ch 4, 5 - 60 by weight of (meth) acrylate, 2 - hydroxyethyl or 2 - hydroxypropyl, and 32 - 90 by weight of the n - vilnylpyrrolidone. It is prepare these polymers by a radical polymerisation of the mixture c - above, until a degree of conversion of at least 70 with respect to the total weight of the initial charge, the hydrogels being obtained by treatment with water until the swelling in the electrolyte. / p & & p & the invention finds its main application in the manufacture of the contact lenses and other protheses.