GB1024430A - Improvements in or relating to vinyl polymers - Google Patents

Abstract

Vinyl chloride or a mixture thereof with at least one copolymerizable monomer is polymerized in an aqueous medium by contacting with 0.002 to 3.0% by weight of the monomer of hydrogen peroxide, 0.003 to 3.0% by weight of the monomer of an alkali metal formaldehyde sulphoxylate and 0.2 to 1.5% by weight of the monomer of a fatty acid sulphate salt of formula R-(OR1)nOSO3Y where R1 is a saturated C1- 3 hydrocarbon radical, R is a C6- 20 aliphatic hydrocarbon radical, Y is an alkali metal and n is 0 to 10. Preferred sulphates are sodium tridecyl and lauroxy-ethyl sulphates. Specified comonomers are vinyl alkanoates, vinyl benzoate, acrylic and methacrylic esters, amides and nitriles, and crotonic, maleic, fumaric and itaconic esters. Polymerization may be effected in the presence of seed latices, and the polymers recovered by spray-drying. The polymers may be compounded with plasticizers and stabilizers to give low viscosity plastisols suitable for coating and slush moulding. In examples: (1) a seed latex is produced using vinyl chloride, hydrogen peroxide, sodium formaldehyde sulphoxylate and sodium tridecyl ether sulphate; (2) vinyl chloride is polymerized in the presence of the seed latex (1) and the same catalyst and emulsifier; the processes of (1 and 2) are repeated using (5 and 6) sodium lauroxyethyl sulphate in place of sodium tridecyl sulphate; and mixtures of (9) vinyl chloride and vinyl acetate, and (13) vinyl chloride and methyl methacrylate in place of vinyl chloride. The products are mixed with dioctyl phthalate and barium/cadmium/zinc stabilizers to form plastisols. Comparative runs using potassium persulphate and sodium metabisulphite as catalyst are given.