Disclosed is a water-insoluble addition copolymer of an ethylenically unsaturated unsubstituted amide and at least one other ethylenically unsaturated monomer comprising sufficient amide groups mono-functionally bonded to a polyaldehyde to render the copolymer thermosettable. The copolymer is adapted for use as or for formulation in a binder. Such a binder is readily made from a copolymer latex and is useful in processes for the preparation of products such as nonwoven fabrics and bonded papers.