GB573055A - Improvements in or relating to the interpolymerisation of acrylonitrile - Google Patents

Abstract

Monomeric acrylonitrile in admixture with at least one other unsaturated compound which will polymerize therewith to form an inter or heteropolymer is emulsified in an aqueous medium containing a dissolved salt of perdisulphuric acid and a dispersing agent consisting of an alkali metal salt of an alkyl sulphate or sulphonate containing 12 to 18 carbon atoms whose activity is unaffected at pH values between 3 and 5 and the mixture is polymerized at a temperature between the freezing point of the aqueous phase and about 80 DEG C. while maintaining a substantially oxygen-free atmosphere. Suitable compounds with which acrylonitrile may be interpolymerized are methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, 2-nitro-2-methyl propyl methacrylate, methoxyethyl methacrylate, chloroethyl methacrylate, phenyl methacrylate, cyclohexyl methacrylate, and the corresponding esters of acrylic acid; acryl-and methacrylamide or monoalkyl substitution products thereof; unsaturated ketones such as methyl vinyl ketone, phenyl vinyl ketone, and methyl isopropenyl ketone; vinyl halides such as vinyl fluoride, vinyl chloride and vinyl bromide; asymmetrical dihalogeno ethylenes such as dichloroethylene; vinyl carboxylates such as vinyl acetate vinyl chloro-acetate, vinyl propionate and vinyl stearate, ethylene-alpha, beta-dicarboxylic acids or their anhydrides or derivatives such as diethyl fumarate, diethyl maleate, maleic anhydride, citraconates and mesaconates, mono- and diolefines and substitution products thereof as butadiene, isoprene, isobutylene, haloprenes, styrene, monovinyl acetylene, and similar compounds. A suitable salt of perdisulphuric acid is the potassium, sodium or ammonium salt. It is employed in an amount varying from .1 to 10 per cent of the amount of monomer. Suitable dispersing agents are dodecyl-1 acid sulphate, tetradecyl-1 acid sulphate, octadecyl-1 acid sulphate, dodecene-1-sulphonic acid, tetradecane - 1 - sulphonic acid, hexadecane - 1 - sulphonic acid and octadecane-1-sulphonic acid, or sodium cetyl sulphate or the salts of longchain sulphonated paraffin oil hydrocarbons. The amount of dispersing agent used may vary from .2 to 5 per cent based on the weight of the aqueous medium. Reaction is accompanied by agitation of the mixture and is performed in a vessel of stainless steel, nickel, silver or lead or one equipped with a glass or enamel liner. The ratio of the aqueous to the non-aqueous phase may vary between 10 : 1 and 1 : 1. Air in the reaction vessel may be replaced by nitrogen, carbon dioxide, methane or helium or sufficient of the inert gas may be introduced to ensure that the partial pressure of oxygen is negligible. The products of the invention may be isolated by drying the emulsion in spray form, by cooling it below the freezing point of the aqueous medium or by the addition of a lower aliphatic alcohol or suitable electrolyte. The examples describe the polymerization of acrylonitrile together with: (I) and (II), vinyl acetate, (III) methyl acrylate, (IV) phenyl methacrylate, and (V) methyl isopropenyl ketone. The emulsions containing the products may be used directly as coating materials. The polymers may be combined with or prepared in the presence of plasticizers, stabilizers, fillers, pigments, dies, softeners or natural or synthetic resins.