| 摘要 |
1289803 PVC powder compositions AMERACE ESNA CORP 19 April 1971 [13 April 1970] 26193/71 Heading C3P A free-flowing powder mixture suitable for processing into microporous articles is prepared by forming a solid mixture of a vinyl chloride resin powder and a powder consisting of silica or a silicate (e.g. sodium or calcium silicate), and adding to the agitated mixture a volatile resin solvent and a non-solvent liquid, the two additions being effected in either order or simultaneously and at rates less than the maximum absorption rates of the solvent and the liquid by the silica, whereby a stable, damp, free-flowing powder is formed. The resin may be a vinyl chloride homopolymer or a copolymer with vinyl acetate, vinylidene chloride or propylene. The solvent may be acetone, an ether, dimethylformamide, o-chlorobenzene, nitrobenzene, tetrahydrofuran, methylcyclohexanone, methyl ethyl ketone, methyl isopropyl ketone or cyclohexanone. The non-solvent may be water. The initial solid mixture may additionally comprise one or more of: polyvinyl acetate, polypropylene, polyethylene, polyacrylates, carbon black, lead stearate, dibutyltin dilaurylmercaptide and a surfactant. |
