Patent GB-494752-A (GB)
Title: Improvements in and relating to the polymerization of halogen butadienes
IPC: C08F236/16
Filed: 1937-01-25
Abstract: In the emulsion polymerization of halogen-2-butadienes-1-3 in the presence of polymerizable a -b  unsaturated compounds such as unsaturated aldehydes, ketones, acids and their esters, anhydrides and nitriles, fat alcohol sulphates or sulphonates or their derivatives or quaternary ammonium salts are used as emulsifying agents.  A large number of specific unsaturated compounds within the above definition are mentioned.  The emulsifying agents mentioned may be used in acid, neutral or alkaline solution.  The polymerization may be effected in the presence of still other polymerizable compounds such as vinyl compounds, or in the presence of film-forming compounds such as resins, cellulose derivatives, plasticizers and drying oils, while pigments, dyes, antioxidants and other modifying agents may be added at any time. In examples: (1) 150 parts of chloroprene and 50 parts of methyl methacrylate are emulsified with sulphated oleyl acetate and kept at 40 DEG  C. for 1,5 hours; then phenyl-b -naphthylamine is added and coagulation is effected with sodium chloride; (2) a mixture of 72 parts of chloroprene, 8 parts of methyl vinyl ketone and 0,8 parts of benzoyl peroxide is emulsified in aqueous sodium salts of the reaction product of sulphuric acid on a mixture of long-chain alcohols (principally cetyl and stearyl), and kept at 0-10 DEG  C. for 24 hours; the emulsion is then stabilized with ammonia and ethyl-b -naphthylamine.  A latex may also be prepared from chloroprene and benzal acetone in the ratio 9 : 1. Specifications 387,340, 387,363; 393,172, [Group V], and 469,976 are referred to.  The Specification as open to inspection under Sect. 91 is not limited to the use of a particular kind of emulsifying agent, and includes broadly the polymerization of halogen-2-butadienes-1-3 in the presence of a polymerizable a -b -unsaturated compound, mention being made of ethyl vinyl ketone, phenylvinyl ketone and methyl, isobutyl, octyl, stearyl, naphthenyl, abietyl, cyclohexyl, phenyl b -dimethylaminoethyl, b -piperidylethyl, b -dicyclohexylaminoethyl acrylates and alkyl phenyl ketones. The polymerization may be effected in the presence of light, heat, air, oxygen, inert solvents or diluents and at pressures up to 6000 atmospheres.  For emulsion polymerization any emulsifying agent may be used, such as alkali metal oleates and water-soluble salts of alkyl naphthalene sulphonic acids.  Additional examples describe the polymerization of chloroprene together with (a) acrylic nitrile with irradiation at 27 DEG  C. and precipitation with alcohol; (b) methacrylic nitrile in sodium oleate emulsion; (c) methyl vinyl ketone and benzoyl peroxide, the mixture being heated at 60-75 DEG C. for 5 hours and distilled under reduced pressure, yielding some monomer and chloro-4 (or 5)-tetrahydro 1-2-3-6-acetophenone and a rubber-like residue, but it is stated that when the heating occurs with the addition of pyrogallol the chief product is the above acetophenone derivative; (d) methyl vinyl ketone, the mixture being allowed to stand for 5 days; (e) ethyl fumarate in sodium oleate emulsion at 0-10 DEG  C. for 48 hours; (f) methyl acrylate with irradiation for 2 days at room temperature; (g) acrolein with irradiation at 30 DEG  C. for 24 hours; (h) crotonaldehyde in sodium oleate emulsion at 10 DEG  C. for 24 hours.  This subject-matter does not appear in the Specification as accepted.