GB573965A - Manufacture of new rubber-like polymeric materials - Google Patents

Abstract

Polymeric materials are prepared by polymerizing a halogen-substituted 1 : 3 butadiene with an ester of a monohydric unsaturated alcohol of not more than 10 carbon atoms and an alpha-unsaturated alpha, beta-dicarboxylic acid, i.e. an acid having only two carboxyl groups which are attached to adjacent carbon atoms of which at least one is directly attached to an ethylenic double bond. The preferred starting materials are 2-chloro-1 : 3-butadiene and the diallyl or di-(beta-methylallyl) esters of maleic or fumaric acids. Also specified are the following : 2 - bromo - 1 : 3 - butadiene, 2 - iodo - 1 : 3 - butadiene, 1 - chloro-, and 2 - chloro - 3 - methyl-, 1 - methyl - 2 - chloro-, 2 : 3 - dichloro-, and 1 : 2 : 4 - trichloro - 1 : 3 - butadienes; the following esters: diallyl maleate, di(alphamethyl-ally) maleate, ditiglyl maleate, di(alpha - methyl - allyl) citraconate, di - (1 : 2 - butadiene - 4 - yl) ethyl maleate, diallyl chloro - maleate, di-propargyl bromomaleate, di - (2 : 4 - hexadiene - 6 - yl) maleate, di - (1 - butene - 4 - yl) phenyl maleate, dicinnamyl bromomaleate, dicrotyl itaconate, digeranyl ethyl maleate, diallyl glutaconate, di-(alpha-methyl allyl) fumarate, dipropargyl fumarate, di-(1 : 2-butadiene4-yl) fumarate, dicrotyl chlorofumarate, dicinnamyl mesaconate, ditiglyl propylfumarate, and di-(alpha-methyl allyl) phenyl fumarate. Other alcohols mentioned are allyl carbinol, 2 : 4-hexadiene-1-ol, ethinyl dimethyl carbinol, and styryl carbinol; other acids are, in general, the various mono- or disubstitution products of maleic and fumaric acids. The polymerization may be carried out by any of the conventional methods such as in bulk without solvents or diluents, in the presence of an inert diluent, or preferably, in emulsion. To obtain products of predominantly rubber-like properties, at least 50 per cent by weight of the total polymerizables should be haloprene. The preferred initial ester concentration is 15 to 40 per cent or, more preferably, 20 to 30 per cent. In aqueous emulsion the polymerization is preferably carried out under essentially neutral or slightly acidic conditions. It is desirable to employ emulsifying agents which function under acidic conditions, for example sodium octyl, cetyl, and oleyl sulphates, sodium isopropyl naphthalene sulphates and the potassium or ammonium salts; N-stearyl betaine, N - hydroxy propyl-C-cetyl betaine, C-cetyl betaine, organic or inorganic salts of long chain aliphatic amines such as octyl, lauryl, oleyl, stearyl amines and cetyl para-dimethyl aminobenzoate. Under alkaline conditions there may be used the sodium or potassium salts of oleic, palmitic, stearic, linoleic, linolenic, abietic (rosin) acids. Polymerization catalysts which may be added include ammonium, potassium or sodium persulphates, sodium or potassium perborates, hydrogen peroxide, acetyl peroxide, benzoyl peroxide; when an alkaline emulsion system is employed, such additions are usually necessary for example in a sodium rosinate solution. The preferred polymerization temperature is about 20 DEG to 50 DEG C. Modifying agents employed include mercaptans, for example octyl, lauryl, or xylyl mercaptans, hydrogen sulphide and thioglycollic acid, toluene sulphinic acid and sulphur dioxide. The polymeric products made from the haloprenes may be plasticised with a small amount of a thiuram sulphide, preferably a tetra-substituted thiuram disulphide such as tetra methyl-, tetra ethyl-, tetra butyl-, or dipentamethylene-thiuram disulphide and other agents described in U.S.A. Specification 2,234,215 including the thionaphthols and the substituted ammonium salts of disubstituted dithiocarbamic acids. Prior to coagulation of the copolymers it is desirable to incorporate small amounts of anti-oxidants, particularly secondary aromatic amines such as phenyl alpha or phenyl beta naphthylamine and diphenylamine. Coagulation may be carried out by addition of an aqueous solution of sodium chloride, magnesium sulphate, aluminium sulphate, by the addition of acids, bases, or alcohols or by freezing. The products may be compounded with zinc oxide, magnesium oxide and lead oxide; reinforcing or semi-reinforcing carbons blacks and sulphur may also be incorporated. Other polymerizable or non-polymerizable compounds may be present such as styrene, vinyl acetate or propionate, esters of acrylic or methacrylic acids, acrylonitrile, methacrylo nitrile, asymmetrical dichloro ethylene, vinyl chloride, and also film-forming materials such as natural or synthetic resins, drying oils, cellulose derivatives. The haloprene should comprise at least half of the total weight and the unsaturated ester should be present in greater amount than the vinyl or vinylidene compound or film-forming material. In examples: (1) chloroprene and diallyl fumarate are interpolymerized and the treated coagulant compounded with magnesium and zinc oxides and carbon black; (2) chloroprene and di(beta-methyl-allyl) fumarate are similarly polymerized; (2) chloroprene and di(beta-methyl-allyl) maleate are also interpolymerized as in example (1).