Thermosetting poly(thio)urethane formulation comprising at least one block copolymer and use thereof in optics for the production of organic lenses having improved toughness

Abstract

The invention relates to a polymerisable liquid mixture comprising: (a) a polymerisable thermosetting composition which is a precursor by polymerization of a first thermoset polymer material, said composition containing at least one polythiol and/or one polyol, preferably a polythiol, and at least one polyiso(thio)cyanate; and (b) a second polymer material solubilized in the aforementioned polymerisable thermosetting composition, whereby the second material (i) contains at least one block copolymer comprising at least two polymer blocks A and B, namely an elastomer block A and a hydrophilic block B, and, following polymerization of the polymerisable mixture, (ii) forms domains which are rich in elastomer block A and which are dispersed throughout the first material, said domains being smaller than 80 nanometers and preferably smaller than 50 nanometers. The invention also relates to a transparent article having improved toughness, which is produced by means of polymerization of the above-mentioned polymerisable mixture, comprising an alloy of a first thermoset polymer material forming the matrix of said article and of a second polymer material which is dispersed throughout said first material. The aforementioned articles have improved resistance to impact and to crack propagation. The invention is suitable for use in ophthalmic optics.