| 摘要 |
A process for the manufacture of a vinyl ester polymer or copolymer dispersion comprises polymerizing a vinyl ester or copolymerizing a vinyl ester with a copolymerizable substance, in an aqueous phase in the presence of a water-soluble salt of vinyl sulphonic acid, and an emulsifier that in a 1% by weight aqueous solution reduces the surface tension of water at 20 DEG C. to a value in the range of 33-45 dynes/cm. The vinyl ester may be vinyl acetate, vinyl propionate, vinyl butyrate or vinyl benzoate, and it may be copolymerized with vinyl chloride or with an ester of a monohydric aliphatic alcohol containing 1 to 8 carbon atoms with acrylic, maleic, fumeric or itaconic acid. The soluble salt is preferably sodium vinyl sulphonate in an amount of 0,1 to 2% calculated on the weight of monomer. The emulsifier may be a condensation product of polypropylene oxide with ethylene oxide. As catalysts, there may be used hydrogen peroxide, potassium or ammonium persulphate, sodium perborate, sodium or potassium peroxide or urea peroxide, or a redox activating system with potassium persulphate and sodium bisulphite, or a combination of hydrogen peroxide with cobalt salts. The polymerization may be performed at a pH of 3-7 under nitrogen. Specification 466,133 is referred to. |
