| abstract |
A light-curable ethylenically unsaturated liquid coating composition which cures to provide low modulus coatings adapted for the primary or single coat coating of optical glass fiber and having improved adhesion is disclosed. This composition comprises: (1) an acrylate-terminated polyurethane oligomer; (2) a monoethylenically unsaturated liquid having a glass transition temperature, measured on a homopolymer thereof, below about 0 DEG C. and which reduces the glass transition temperature of the coating; and (3) a silsesquioxane oligomer polyacrylate which is the condensation reaction product of about two moles of hydroxyalkyl acrylate in which the alkyl group contains from 2 to 4 carbon atoms, with about one mole of a silsesquioxane polysilanol, the proportion of the silsesquioxane oligomer polyacrylate is in the range of from about 2% to about 60% of the weight of the coating composition. |