Disclosed herein are sheets or webs of a resin-impregnated fibrous material, including an impregnating resin, which includes a combination of a) at least one resin component A, which is selected from the group consisting of aminoplast resins and phenoplast resins and mixtures thereof; and b) at least one resin component B, which is an oligomer or polymer having ethylenically unsaturated double bonds, where at least 40 mol % of the ethylenically unsaturated double bonds are selected from the group consisting of allyl groups, acryl groups and methacryl groups. Further disclosed herein is a process for producing a resin-impregnated fibrous material, which includes impregnating a fibrous material in the form of a sheet or a web with a liquid resin composition including a combination of a) the resin component A; and b) the resin component B.