GB979329A - Olefin copolymers and process for preparing them - Google Patents

Abstract

Substantially amorphous copolymers are produced by copolymerizing ethylene, a cyclo-olefin containing from 4 to 8 carbon atoms in the ring which may be substituted with an alkyl radical containing from 1 to 8 carbon atoms, and at least one a -olefin having the formula CH2=CHR in which R is an alkyl group containing from 1 to 6 carbon atoms. Specified a -olefins are:-propylene, butene-1, methyl-3-butene-1, pentene-1, methyl-4-pentene-1 and hexene-1. Specified cyclo-olefins are:-cyclobutene, cyclopentene, cyclohexene, cycloheptene, cis-cyclo-octane and 4-methyl cyclopentene-1. The catalysts used are preferably preformed and comprise vanadium compounds reacted with organo-metallic compounds of metals of Group Ia, II and IIIa of the Mendel<\>eeeff Periodic Table. Catalyst components exemplified are vanadium tetrachloride, vanadyl trichloride, vanadium triacetyl acetonate and aluminium trihexyl. A number of other suitable catalyst components are specified. The copolymerization may be effected in hydrocarbon solvents of which n-heptene and toluene are exemplified. The copolymerization reaction is terminated by the addition of methanol or methanol plus phenyl-b -naphthylamine; the copolymer then being purified by washing with hydrochloric acid and water and finally is coagulated with an acetone-methanol mixture. The copolymers may be vulcanized by mixing with sulphur, zinc oxide, phenyl-b -naphthylamine, tetramethylthiuram disulphide and mercaptobenzothiozole and heating the resultant mixture in a press. In some of the examples radio-active cyclo-olefins are used and the proportion of the cyclo-olefin in the resultant copolymer determined by radio chemical analysis. Specification 967,836 is referred to.