| 摘要 |
Substantially hydroxy free, liquid, ultraviolet-curable compositions comprise cationically polymerizable ethylenically unsaturated material including a vinyl ether-terminated polyurethane which is the reaction product of isocyanate-reactive material including a monohydric vinyl ether and a diisocyanate having the formula: <IMAGE> in which R is an alkylene group containing from 1-10 carbon atoms, this polyurethane having a number average molecular weight in the range of from 2000 to 6000, and a curing effective amount of a cationic photoinitiator which initiates a cationic cure when exposed to ultraviolet light, but less than 1% thereof based on the weight of the unsaturated material subjected to polymerization. These coatings are applied with a thickness of from 1 to 10 mils and cured with ultraviolet light, and they are particularly adapted to provide primary and single coatings for optical glass fiber. |
