| 摘要 |
679,693. Water resistant film. CELLOPHANE SOC. ANON. June 23, 1950 [July 1, 1949], No. 15781/50. Class 140. A water resistant film is formed, by coating a thin hydrophilic film base such as regenerated cellulose with one or more surface layers of a copolymer of vinyl chloride and vinylidene chloride containing up to 25 per cent by weight of the latter, said layers further containing up to 5 per cent and preferably 2-3 per cent by weight of the copolymer of a di-alkyl ether of which the alkyl groups contain 12-18 and preferably 16--18 carbon atoms, the preferred ether being dicetyl ether. The layers may be applied from aqueous dispersions, or solutions in methylethylketone with or without toluene, up to 5 per cent of a plasticizer such as ethyldiglyol phthalate or dicetyl phthalate being optionally added. The adhesion of the layers may be enhanced by the incorporation of a resin (e.g. melamine formaldehyde) substrata, an example relating to impregnation of the film with a 5 per cent dispersion of dimethylolmelamine with a trace of lactic acid to bring the pH to 4, prior to being coated. Specifications 380,483; 467,901 and 497,001, [both in Group IV], are referred to. |
