| 摘要 |
1,199,652. Polyvinyl acetals. UNION CARBIDE CORP. 11 July, 1967 [11 July, 1966], No. 13171/70. Divided out of 1,199,651. Headings C3G and C3P. Polyvinyl acetals are produced by (a) contacting a non-aqueous dispersion of homopolymerized 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 polymerized vinyl ester having an average particle size of 0À05 to 50 microns, with: (1) 0À05 to 3À00 moles, per mole of polymerized vinyl ester, of an aliphatic alcohol having from 1 to 6 carbon atoms; (2) 0À03 to 1À5 moles, per mole of polymerized vinyl ester, of an aliphatic aldehyde or oligomers thereof having from 1 to 6 carbon atoms; and (3) A catalytic amount of an acid catalyst, for at least 5 minutes at a temperature of from 15‹ to 70‹ C.; and (b) Recovering the polyvinyl acetal. The vinyl ester may be vinyl acetate, the polymeric organic interfacial agent may be an ethylenevinyl acetate copolymer, the aliphatic alcohol may be methanol, the aliphatic aldehyde may be butyraldehyde or trioxane and the acid catalyst may be hydrochloric acid. |
