| 摘要 |
<p>1476958 Swellable coatings DOW CHEMICAL CO 14 June 1974 [20 June 1973] 26539/74 Heading B2E '[Also in Division C3] Substrates coated with water-swellable polyelectrolytes are produced by depositing on the substrate a film of a composition comprising (1) water, a lower alcohol or a mixture thereof, (2) 15-40 wt.%, based on (1), of a carboxylic polyelectrolyte soluble in (1) and which is a salt of a polymer or copolymer containing units of acrylic, methacrylic, maleic or fumaric acid or of a half-ester of maleic or fumaric acid, and (3) 0.1-10 wt.%, based on (2), of a cross-linking agent reactive with carboxylate groups, and heating the film to remove excess solvent and effect curing. The compositions may also contain a plasticiser, e.g. methyl cellulose or glycerol, and a surfactant, e.g. sodium lauryl sulphonate. The substrate may be a fibrous material, e.g. cellulose batting, paper or cloth, or may be of plastic or metal. In Examples, the substrate is polyethylene sheet, "Mylar" (Trade Mark) sheet, chromium plate, a paper towel or a polystyrene meat tray; the polyelectrolyte is one of numerous polymers containing sodium acrylate, methacrylate, maleate or itaconate units or ammonium maleate units, usually with other monomer units; and the cross-linking agent is 1, 3-dichloroisopropanol, epibromohydrin, epichlorohydrin, an aryl sulphonium zwitterion, a bisphenol A/epichlorohydrin epoxy resin or a diglycidyl ether of glycerol, 1, 4-butane diol, neopentyl glycol or polypropylene glycol.</p> |
