Verfahren zur Herstellung von waessrigen Mischpolymerisatdispersionen

A process for preparing coating compositions suitable for application to film materials comprises forming an aqueous dispersion containing 80 to 97 wt. per cent of vinylidene chloride and 3 to 20 wt. per cent of at least one other polymerizable mono-olefinic monomer; incorporating therein 0,5 to 2% (by weight of the total monomers) of one or more alkali metal or ammonium C8-18 alkyl suphates; copolymerizing the monomers; and subsequently incorporating 0,5 to 2% of one or more alkali metal or ammonium C18-18 alkyl sulphates and 0,5 to 3% of one or more alkali metal or ammonium C5-20 alkyl aryl sulphonates, the total amount of the sulphates added being 1,5 to 3%. Preferred comonomers have the formula CH2=CR1X where R is hydrogen, halogen or a saturated aliphatic radical and X is Cl, Br, F, CN, C6H5, COOH, COOR1, COR1, CHO, OC6H5, CONH2 CONHR1, or CONR12 where R1 is an alkyl radical. Comonomers specified are citraconic, mesaconic and itaconic acids and anhydrides; acrylic, methacrylic, and methyl methacrylic acids; methyl, ethyl, isobutyl, butyl, octyl, 2-ethylhexyl, phenyl, cyclohexyl, p-cyclohexylphenyl, methoxyethyl, chloroethyl and p 2-nitro2-phenylpropyl acrylates and methacrylates; methyl and octyl alphachloroacrylates; methyl isopropenyl ketone; acrylonitrile; methacrylonitrile; methyl vinyl ketone; vinyl chloride, acetate, propionate, chloroacetate and bromide; styrene; vinyl naphthalene; ethyl vinyl ether; N-vinyl phthalimide, succinimide and carbazole; isopropenyl acetate; methylene diethyl malonate; acrylamide, methacrylamide and their monoalkyl substituted derivatives; phenyl vinyl ketone; diethyl fumarate and maleate; dibutyl and methylene diethyl itaconates; vinyl pyridine; maleic anhydride; and allyl glycidyl ether. The polymerization may be promoted by a catalyst, e.g. ammonium persulphate, an activator therefore, e.g. sodium metabisulphite, and an accelerator, e.g. ferrous ammonium sulphate. In examples the process is applied to the copolymerization of vinylidene chloride, methyl acrylate and itaconic acid (94:6:1) and of vinylidene chloride, methyl acrylate, acrylonitrile, methacrylic acid and allyl g lycidyl ether (94:3:3:1:1) In Example 1 ethylene glycol and hydrogen peroxide are added to the product dispersion. Specifications 545,523, 573,932, 593,947, 647,593, 654,342, 656,643, 684,105, 693,496 and 777,584 are referred to.