| 摘要 |
Carboxyl-containing graft polymers in which vinyl carboxylates and optionally further ethylenically unsaturated monomers are polymerically grafted onto carboxyl-containing polyurethane graft bases by means of free radical-initiated graft polymerisation, and hydrolysis (saponification) products and salts of these carboxyl-containing graft polymers, can be obtained by grafting vinyl carboxylates having 3 to 20 carbon atoms and optionally further ethylenically unsaturated, polymerisable monomers, which are optionally copolymerisable, preferably in amounts of from 10 to 95% by weight, based on the carboxyl-containing graft polymer, onto a carboxyl-containing polyurethane graft base containing at least 2 urethane groups in the molecule, by means of free radical-initiated graft polymerisation, and optionally subsequently saponifying all or some of the vinyl ester units and any further saponifiable monomer units in the grafted-on polymer radicals of the graft polymers by hydrolysis and/or alcoholysis or converting the carboxyl groups to salts. Preferred vinyl esters to be grafted on are vinyl acetate and/or vinyl propionate and optionally vinyl versatate. The graft polymerisation is preferably carried out in solution or in bulk. Unsaponified graft polymers are suitable, inter alia, as adhesives, in particular as hot-melt adhesives, and, in their water-soluble or water-dispersible salt forms, as dispersants. Fully or partially saponified graft polymers are suitable, inter alia, for the production of films (sheeting). Depending on the carboxyl group content of the polyurethane graft base, the degree of grafting, the degree of hydrolysis and the nature of the grafted monomers, the graft polymers, compared with polyvinyl alcohol, have significantly improved solubilities in aqueous-alkaline media and reduced melting points, so that they are advantageously suitable for the production of pressed and extruded films under mild temperature conditions without the concomitant use of organic plasticisers. Saponified graft polymers are furthermore suitable, inter alia, as adhesives, as dispersants in aqueous-alkaline media and as sizes and lubricating agents in textile processing. |
