| 摘要 |
1,199,651. Polyvinyl alcohols. UNION CARBIDE CORP. 11 July, 1967 [11 July, 1966], No. 31927/67. Headings C3G and C3P. Polyvinyl alcohols are produced by contacting a non-aqueous dispersion of homo-polymerized vinyl ester, having up to 20 carbon atoms per vinyl ester monomer unit, dispersed in an inert hydrocarbon diluent by polymerizing the vinyl ester in the presence of a polymeric organic interfacial agent, the homo-polymerized vinyl ester having an average particle size of 0À05 to 50 microns, with 0À01 to 10À0 moles, per mole of the homo-polymerized vinyl ester, of an aliphatic alcohol having from 1 to 6 carbon atoms and 0À001 to 0À10 moles, per mole of the homopolymerized vinyl ester, of an alcoholysis catalyst for at least 5 minutes at a temperature of from 15‹ to 100‹ C. and recovering the polyvinyl alcohol. The homo-polymerized vinyl ester may be polyvinyl acetate, the polymeric organic interfacial agent may be an alpha olefin-vinyl ester, e.g. ethylene/vinyl acetate copolymer, polyvinyl ethyl ether, propylene oxide rubbers or a butadiene-styrene copolymer, and the aliphatic alcohol may be methanol or ethanol. |
