AN OPTICAL FIBER COATED WITH AN ORGANOPOLYSILOXANE CURABLE WITH ACTINIC RAYS

摘要

A coated optical fiber is prepared by providing coating a fused quartz glass optical fiber with an ultraviolet-curable organopolysiloxane or a composition comprising the same and irradiating the coating layer with ultra-violet or other actinic radiation. Specifically, the organopolysiloxane is represented by the average unit formula (R<1>)a[(R<3>O)n(R<4>)3-n-m(R<5>O)mSi-R<2>-]bSiO(4-a-b) /2, in which a is a positive number in the range from 1.6 to 2.2 and b is a positive number in the range from 0.02 to 0.5 with the proviso that a+b is in the range from 1.8 to 2.2; n is 1,2 or 3; m is zero, 1 or 2 with the proviso that n+m is 1,2 or 3; the groups denoted by R<1> and R<4> are each, independently from the others, a substituted or unsubstituted monovalent hydrocarbon group; R<2> is a divalent hydrocarbon group having 2 to 4 carbon atoms or an oxygen atom; R<3> is a monovalent organic group having 4 to 25 carbon atoms and 1 to 3 ethylenically unsaturated groups with the proviso that R<3> has at least 2 ethylenically unsaturated groups when n is 1; R<5> is a monovalent hydrocarbon group free from aliphatic unsaturation having 1 to 18 carbon atoms or an organosilyl group represented by the general formula R<6> being a monovalent hydrocarbon group having 1 to 9 carbon atoms and p being zero or a positive integer.