| abstract |
A method for increasing an adhesive to a substrate is disclosed which utilizes a hydrophilic, high molecular weight, nonionic polyurethane adhesive. The polyurethane adhesive is soluble in water and a 1% by weight solution of the adhesive in water at 20% has a specific viscosity of at least 0.4. The nonionic polyurethane contains the following structural units: n a) —O—(CH 2 —CH 2 O) n where n is 8 to 500; n b) —CO—NH—X—NHCO— where X is an aliphatic or cycloaliphatic group; and n c) —O—Y—O— wherein Y comprises a hydrophobic moiety from the groups n (—CH 2 —CH(CH 3 )—O) m —CH 2 —CH(CH 3 )—, n (—CH 2 CH(C 2 H 5 )—O) m —CH 2 —CH(C 2 H 5 )—, n (—CH 2 —CH 2 —CH 2 —CH 2 O) m —CH 2 CH 2 CH 2 CH 2 —, n alkylene groups having from 2 to 44 carbon atoms, cycloalkylene groups having from 6 to 44 carbon atoms and mixtures thereof. |