Patent ID: 7320831

Claim:
A binder solution for a fibrous web, said solution comprising: (a) an aqueous solvent medium; and (b) a binder composition comprising a salt sensitive copolymer that incorporates the residue of: (i) from about 60 to about 90 weight percent of vinyl acetate; (ii) from about 2 to about 20 weight percent of a carboxylic acid monomer; and (iii) from about 5 to about 30 percent vinyl ester of the formula: where R 1 and R 2 are alkyl groups collectively having between 3-14 carbon atoms, wherein said copolymer is neutralized with base at least to the point where it is water soluble, and wherein said binder composition has a characteristic wet strength of at least about 75 gf/in in a 10% NaCl solution, and a characteristic wet strength of less than 50 gf/in in deionized water.