GB708546A - Improvements in or relating to continuous polymerization processes and resulting products - Google Patents

Abstract

In polymerizing unsaturated organic compounds the monomer, a catalyst, and an inert hydrocarbon liquid which is a solvent for the monomer, but a non-solvent and non-swelling medium for the polymers, are continuously added to a slurry of a polymeric material obtained by polymerizing the monomer in the same hydrocarbon liquid, while maintaining the temperature of the slurry between 40 DEG and 150 DEG C., and continuously removing a minor portion of the slurry. Styrene and maleic anhydride copolymers are exemplified but vinyl acetate, vinyl ethers, di-vinyl benzene, p-chloro styrene, p-methyl styrene, or gaseous vinyl chloride (under pressure) may wholly or partially replace the styrene, and itaconic, citraconic, acrylic or methacrylic anhydrides or the alkyl half esters of maleic acid, may replace the maleic anhydride. Terpolymers of styrene or vinyl acetate with maleic anhydride and acrylic or methacrylic acid, or acrylonitrile may be prepared. Acrylic and methacrylic acids, acrylamide, acrylonitrile and other unsaturated compounds containing carbonyl, carboxylic anhydride, amide and nitrile groups may also be polymerized. The inert hydrocarbon liquid includes their chlorinated derivatives and examples are benzene, toluene, xylene, chlorobenzene, dichlorobenzene, chlorotoluene, heptane, hexane, octane and nonane, cyclo-hexane and pentane, ethylene dichloride and carbon tetrachloride. The catalysts may be selected from diamyl sulphide, ditertiary dodecyl disulphide, a , a 1-azobis isobutyl nitrile, ditertiary-butyl perbenzoate or peroxide, ditertiary-amyl peroxide, diethyl peroxide, lauroyl and benzoyl peroxides and t-butyl and cumene hydroperoxides. Cross-linking and chain transfer agents such as maleic or fumaric esters of polyhydric alcohols, diisopropenyl or divinyl benzene, dodecyl mercaptan and carbon tetrachloride may be present. The initial polymer slurry may be prepared by a batch process and additional quantities of monomer, hydrocarbon liquid and catalyst are then added continuously, preferably under reflux conditions and at an equivalent rate to that at which the slurry is removed. The polymer is separated by filtration or by centrifuging and treated with hot air and steam. The product is in the form of free-flowing particles of 8 to 80 microns diameter and of apparent density between 28 and 40 lbs. per cubic foot. Examples describe the copolymerization of styrene and maleic anhydride, alone or with methyl acid maleate, divinyl benzene and acrylic acid. Organic solvent solutions of the product may be used to coat fabrics, metal or wood and aqueous solutions of the alkali metal or ammonium salts used to size nylon yarn. Specification 459,947 is referred to.