GB957105A - Elastomeric copolymers and process for preparing them - Google Patents

Abstract

High molecular weight linear amorphous copolymers of cyclopentadiene or an alkylcyclo-pentadiene with ethylene and at least one aliphatic alpha-olefine having the general formula R-CH=CH2 in which R is an alkyl group containing 1 to 6 carbon atoms are prepared using a catalyst system which is soluble in the hydro-carbons which can be used as copolymerization media, said catalyst system being prepared from (a) dialkyl aluminium monohalides, monoalkyl aluminium dihalides, alkyl beryllium halides or mixtures thereof, and (b) vanadium compounds soluble in hydrocarbons or insoluble but capable of giving soluble compounds by reaction with the aluminium or beryllium compound. Hydrocarbon-soluble vanadium compounds mentioned are vanadium triacetylacetonate, vanadyl diacetylacetonate, vanadyl halogen-acetylacetonates (VOAc2X and VOAcX2), vanadyl trialkoxides, vanadyl halogen alkoxides, vanadium complexes with diketones, ketoesters, aminoalcohols, aminoaldehydes, oxyaldehydes and complexes of vanadium halides with Lewis bases e.g. ethers, amines, phosphines, arsines and stibines. Insoluble vanadium compounds mentioned are the salts of organic acids or oxyacids of trivalent or tetravalent vanadium. The polymerization can be carried out at temperatures of -80 DEG C to 125 DEG C. When catalysts prepared from vanadium triacetylacetonate, vanadyl trialkoxides or vanadyl halogen oxides are used, the polymerization is preferably carried out in the presence of ethers or thioethers containing at least one branched alkyl group, aromatic, or cycloaliphatic nucleus, as complexing agent. Aluminium catalyst components mentioned are diethyl aluminium monochloride and diethyl aluminium monofluoride. The copolymerization which may be continuous can be carried out in inert hydrocarbon solvents e.g. butane, pentane, benzene, heptane, toluene, xylene or mixtures thereof, or it may be carried out in the absence of an inert solvent using the monomers themselves in the liquid state. In the examples, ethylene, propylene and cyclopentadiene are copolymerized, the catalyst used being diethyl aluminium monochloride with vanadyl diacetylacetonate, vanadium triacetyl acetonate or vanadium triacetylacetonate plus diisopropylether. In each case the reaction is stopped by adding methanol containing phenyl-beta-naphthylamine as antioxidant, and the product purified by successive treatments with aqueous hydrochloric acid and water under nitrogen and then coagulated by pouring into an acetonemethanol mixture. The copolymers may be vulcanized by heating with sulphur, zinc oxide, lauric acid, mercaptobenzothiazol, phenyl-b -naphthylamine and tetramethyl-thiurandisulphide. Specifications 858,067 and 957,103 are referred to.