| 摘要 |
PURPOSE:To obtain a urethane di(meth)acrylate useful as a cladding which gives an optical fiber with a large numerical aperture by using a specific fluoroalkylated diol and a specific fluoroalkylated epoxy compd. as the starting materials. CONSTITUTION:A urethane di(meth)acrylate of formula IV (X is H or methyl; k is 1-30; and it is 2-30) is obtd. by reacting a fluoroaklylated diol of fomrula I (j is 0 or 1; m is 1 or 2; and n is 3-12) with a fluoroalkylated epoxy compd. of formula II, then with a diisocyanate of formula III (R is alkyl, aryl, or cycloalkyl) (e.g. hexamethylene diisocyanate), and with (meth)acryl chloride or (meth)acrylic acid. An optical fiber which has a large numerical aperture and can efficiently take in light from a light source is produced by using, as the cladding, a cured resin compsn. contg. the urethane di(meth)acrylate. |
