Optical fiber coated with an organopolysiloxane curable with actinic rays

Claim 1

A coated optical fiber which comprises: (a) a fused quartz glass-made optical fiber base; and (b) a coating layer on the optical fiber base formed of a coating material comprising, as the principal ingredient thereof, an organopolysiloxane represented by the average unit formula (R.sup.1).sub.a [(R.sup.3 O).sub.n (R.sup.4).sub.3--n--m (R.sup.5 O).sub.m Si-R.sup.2 --].sub.b SiO.sub.(4--a--b)/2, in which 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, 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 --SiR.sup.6.sub.2 --O).sub.p SiR.sup.6.sub.3, R 6 being a monovalent hydrocarbon group having 1 to 9 carbon atoms and p being zero or a positive integer, a is a positive number in the range from 1.6 to 2.2, 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 and R 3 has at least two ethylenically unsaturated groups when n is 1.

Claim 3

A method for the preparation of a coated optical fiber which comprises the steps of: (a) coating a fused quartz glass-made optical fiber base with a coating material comprising, as the principal ingredient thereof, an organopolysiloxane represented by the average unit formula (R.sup.1).sub.a [(R.sup.3 O).sub.n (R.sup.4).sub.3--n--m (R.sup.5 O).sub.m Si--R.sup.2 --].sub.b SiO.sub.(4--a--b)/2, in which 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, 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 --SiR.sup.6.sub.2 --O).sub.p SiR.sup.6.sub.3, R 6 being a monovalent hydrocarbon group having 1 to 9 carbon atoms and p being zero or a positive integer, a is a positive number in the range from 1.6 to 2.2, 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 and R 3 has at least two ethylenically unsaturated groups when n is 1, to form a coating layer; and (b) irradiating the coating layer with ultraviolet light to cure the organopolysiloxane.

Claim 4

A method for the preparation of a coated optical fiber which comprises the steps of: (a) coating a fused quartz glass-made optical fiber base with a coating material comprising, as the principal ingredient thereof, an organopolysiloxane represented by the average unit formula (R.sup.1).sub.a [(R.sup.3 O).sub.n (R.sup.4).sub.3--n--m (R.sup.5 O).sub.m Si--R.sup.2 --].sub.b SiO.sub.(4--a--b)/2, in which 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, 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 --SiR.sup.6.sub.2 --O).sub.p SiR.sup.6.sub.3, R 6 being a monovalent hydrocarbon group having 1 to 9 carbon atoms and p being zero or a positive integer, a is a positive number in the range from 1.6 to 2.2, 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 and R 3 has at least two ethylenically unsaturated groups when n is 1, to form a coating layer; and (b) irradiating the coating layer with ultraviolet light to cure the organopolysiloxane.