| 摘要 |
A solid copolymer of formaldehyde and up to 50 mol. per cent of isobutylene, a vinyl ether, a vinyl nitrogen compound or an alkylene oxide. The polymerization may take place in a liquid medium, e.g. one of the co-monomers or a hydrocarbon containing 3 to 10 carbon atoms, such as heptane, in the presence of a FriedelCrafts metal halide catalyst. Specified comonomers include vinyl ethers in which the other constituent is methyl, isobutyl, 2-ethylhexyl, allyl or vinyl, N-vinyl carbazole, N-vinyl pyrrolidone, N-vinyl methyl formamide and ethylene oxide. Tin tetrachloride or -bromide and boron trifluoride are specified catalysts while a weakly basic material, e.g. an ether, may also be present. The product may be acetylated. Specifications 753,299 and 770,717 are referred to.
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