Crosslinkabel dispersion powders as binders for fibers

A process for binding fiber materials which comprises

• (a) contacting said materials with from 5 to 50% by weight based on the weight of the fiber material, of a binder based on a vinyl ester copolymer dry powder or a (meth)acrylic acid ester copolymer powder, said vinyl ester copolymer comprising at least one monomer selected from the group consisting of vinyl esters of unbranched or branched alkyl carboxylic acids having 1 to 15 C atoms and the (meth)acrylic acid ester copolymer comprising at least one monomer selected from the group consisting of methacrylic acid esters of alcohols having 1 to 10 carbon atoms and the vinyl ester and (meth)acrylic acid ester copolymer, in each case comprising 0.1 to 10% by weight, based on the total weight of the copolymer of at least one ethylenically unsaturated comonomer having a crosslinking action;
• (b) moistening the material with 5 to 60% by weight of water based on the total weight of dry mixture of fiber and binder before or after the binder has been contacted with the fiber material, and
• (c) heating at 100.degree. to 200.degree. C. under a pressure of up to 100 bar to bind the fibers.