Method for manufacturing polyvinyl ethers

Crystalline polyvinyl ethers are prepared by a method which comprises polymerizing vinyl ethers at a temperature not below -30 DEG C. in the presence of a catalyst composition comprising (A) boron trifluoride or a complex thereof with water, an alcohol, ether, aldehyde or carboxylic acid and (B) an organometallic compound of a metal of Group I, II or III of the Periodic Table. The ether may be methyl, ethyl, propyl, n-butyl, isobutyl, amyl, octyl, 2-ethylhexyl, lauryl, stearyl, benzyl or cyclohexyl vinyl ether. Specified organometallic compounds are trimethyl aluminium, triethyl aluminium, tributyl aluminium, triisobutyl aluminium, trioctyl aluminium, dimethyl magnesium, diethyl magnesium, diethyl zinc, butyl magnesium chloride, hexyl magnesium chloride, phenyl magnesium bromide, dimethyl aluminium chloride, diethyl aluminium bromide, diethyl aluminium chloride, ethyl aluminium dichloride, diisobutyl aluminium chloride, diisobutyl aluminium fluoride, ethyl magnesium methoxide, ethyl aluminium dimethoxide, diethyl aluminium hydride, diisobutyl aluminium hydride, butyl lithium, phenyl sodium, and complex salts of ethyl sodium with aluminium triethyl and diethyl aluminium chloride and lithium octyl with aluminium trioctyl. Polymerization may be effected in an inert diluent such as petroleum ether, n-hexane, n-heptane, benzene, toluene and ethyl ether. Amorphous polymer may be removed from the product by extraction with a selective solvent, e.g. water, methanol or methyl ethyl ketone. The products may be used in adhesives and coatings, and made into filaments, films and sheets. Examples described the polymerization of isobutyl vinyl ether in the presence of boron trifluoride etherate and (1) triethyl aluminium and (4) diethyl magnesium; and of methyl vinyl ether in the presence of (2) boron trifluoride etherate and triethyl aluminium, and boron trifluoride and (3) triethyl aluminium and (5) triisobutyl aluminium.