A salt sensitive polymeric binder for use in fibrous webs, where the binder contains a copolymer of carboxylic acid monomer units, acrylate monomer units, and N-alkyl acrylamide units. The copolymer is neutralized at least to the point where it is water soluble. The binders are particularly suitable for strengthening non-woven fibrous webs in disposable articles such as wet-wipes, personal care products, diapers, and the like.