| abstract |
A liquid photocurable plastic composition is disclosed which comprises: (a) from 14% to 70% by weight of a polyurethane (meth)acrylate having a polyoxyalkylene structure in the backbone of the polyurethane, said polyurethane (meth)acrylate containing 0.8 to 8 weight percent of ethylenic unsaturation, from 50% to 98% by weight of the polyoxyalkylene structure, and having a number average molecular weight of 1,000 to 7,000; (b) from 5% to 40% by weight of a polyurethane (meth)acrylate having at least 15% by weight of a tricyclodecane structure in the backbone of the polyurethane and a number average molecular weight of from 500 to 1,000; (c) a reactive diluent; and (d) a polymerization initiator. This combination provides a liquid curable plastic composition suitable as the secondary coating or bundling material for use with optical fibers to provide compositions which photocure rapidly to provide cured coatings which are relatively hard and elongatable and which can be applied at low viscosity without encountering excessive sensitivity to water. |