Abstract: Fiber coatings with low Young's modulus, low fiber pullout force for fibers in the as-drawn state, and small time-dependent increases in pullout force as the fiber ages. The fiber coatings are cured products of coating compositions that include an oligomer formed from an isocyanate, a hydroxy acrylate compound and a polyol. The oligomer includes a polyether urethane acrylate and a di-adduct compound. The reaction mixture used to form the oligomer includes a molar ratio of isocyanate:hydroxy acrylate:polyol of n:m:p, where when p is 2, n is in the range from 3.0 to 5.0 and m is in the range from 1.50n-3 to 2.50n-5. Control of the n:m:p ratio leads to compositions that, when cured, provide coatings and cured products having low Young's modulus, low pullout force on glass, and weak variations with time as the fiber ages.

Abstract: Fiber coatings with low Young's modulus, low fiber pullout force for fibers in the as-drawn state, and small time-dependent increases in pullout force as the fiber ages. The fiber coatings are cured products of coating compositions that include an oligomer formed from an isocyanate, a hydroxy acrylate compound and a polyol. The oligomer includes a polyether urethane acrylate and a di-adduct compound. The reaction mixture used to form the oligomer includes a molar ratio of isocyanate:hydroxy acrylate:polyol of n:m:p, where when p is 2, n is in the range from 3.0 to 5.0 and m is in the range from 1.50n-3 to 2.50n-5. Control of the n:m:p ratio leads to compositions that, when cured, provide coatings and cured products having low Young's modulus, low pullout force on glass, and weak variations with time as the fiber ages.