GB954830A - Hydrocarbon copolymers containing fluorine - Google Patents

Abstract

Copolymers of vinylidene fluoride and 1, 1, 3, 3, 3-pentafluoropropylene are prepared by copolymerising 95 to 5 parts by weight of vinylidene fluoride and 5 to 95 parts by weight of 1, 1, 3, 3, 3-pentafluoropropylene in the presence of a free radical polymerisation initiator at a temperature between -20 and 200 DEG C. under a pressure between the autogenous pressure and 300 atmospheres. The polymerisation may be effected batchwise or continuously with continuous addition of the monomers and other reactants, in aqueous emulsion or suspension, in bulk, in solution or in the presence of excess monomer as reaction medium. Specified catalysts are benzoyl peroxide, p-chlorobenzoyl peroxide,2,4-dichlorobenzoyl peroxide, acetyl peroxide, lauroyl peroxide, t-butyl peroxide, cyclohexanone peroxide, trichloracetyl peroxide, trifluoracetyl peroxide, perfluoropropionyl peroxide, heptafluorobutyric acid peroxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, triisopropylbenzene hydroperoxide, t-butyl hydroperoxide; sodium, potassium, ammonium and barium persulphates, perphosphates and perborates, hydrogen peroxide and barium peroxide; a , a 1-azodiisobutyronitrile and catalyst activators, e.g. sodium bisulphite, metabisulphite and thiosulphate, reducing sugars and iron, copper, silver and titanium sulphates, phosphates and chlorides, may also be used. Buffers, e.g. sodium metaborate and disodium hydrogen phosphate, and chain transfer agents, e.g. lauryl mercaptan, chloroform and carbon tetrachloride may also be present. In aqueous media dispersing agents, e.g. sodium stearate, sodium oleate, potassium palmitate and ammonium perfluorocaprylate, may be used to give stable latices. Dispersions of the copolymers may be coagulated by adding salts or acids, e.g. hydrochloric acid. Solution polymerisation may be effected in the presence of hydrocarbons, alcohols, ethers, esters, ketones and particularly halogenated hydrocarbons, e.g. fluorotrichloromethane, dichlorotetrafluoroethane, perfluorocyclobutane, perfluorodimethylcyclobutane and perfluorocyclohexane, and perfluoropropylpyrane. The copolymers may be thermoplastic or elastomeric. The elastomeric copolymers may be compounded with conventional ingredients, e.g. carbon black and magnesium oxide, and vulcanised with hexamethylene diamine, hexamethylene diamine carbamate, diethylene triamine, triethylene tetramine, cycloalkylene diamines, benzoyl peroxide or irradiation. The copolymers may be moulded, extruded and used in the preparation of films, sheets, tapes, fibres, gaskets, pipes, joints and containers.