| abstract |
A process for the production of an elastomeric material from a homogeneous composition comprising from 50% to 95% by weight of the precursors of a cross-linked elastomeric polyurethane and from 50% to 5% by weight of a polymerisable ethylenically unsaturated material, in which the reaction of the polyurethane precursors is substantially completed before polymerisation of the ethylenically unsaturated material is allowed to proceed to the extent that the polymer so produced forms a separate phase, polymerisation of the ethylenically unsaturated material thereafter being completed, and in which the ethylenically unsaturated material contains at least one polyfunctional ethylenically unsaturated material and is selected so as to produce, after polymerisation, a cross-linked polymer having on average a molecular weight between cross-links of not greater than 2500. |