Soft and tough radiation-curable coatings for fiber optic application

Abstract

A radiation-curable liquid coating composition which cures on radiation exposure to form a soft and tough coating and which is adapted for coating optical fiber is disclosed. This composition comprises a polyurethane, polyamide or polyurea oligomer having (1) a molecular weight in the range of about 2000 to about 8000; (2) amide, urea or urethane groups in an amount of one such group for every 300 to 900 units of weight; and (3) polyalkylene polyether, polyalkylene polysulfide or polyalkylene polyester groups in which the alkylene moiety contains 2-6 carbon atoms. The polyether, polysulfide or polyester constitutes about 40% to about 90% by weight of the oligomer, and each end of the oligomer is terminated with a monoethylenically unsaturated addition polymerizable group. From 20% to 50% of the weight of the composition is a radiation-curable monoethylenically unsaturated monomer having a T.sub.g below about 10.degree. C., and from 2% to 20% of the composition is a monoethylenically unsaturated monomer having a strong capacity for hydrogen bonding, such as vinyl pyrrolidone.

Dependencies are inferred from the claim text.