Polymeric compositions

Stable aqueous polymeric dispersions are obtained by polymerizing, with the aid of a persulphate catalyst, acrylic or methacrylic esters in an aqueous medium in the presence of a water-soluble polysaccharide present in the proportion of 10 to 300 per cent by weight of the ester. Esters specified are methyl, ethyl and butyl acrylates and methyl, beta-ethoxyethyl and butyl methacrylates. Polysaccharides specified are maize, sago or wheat starch or the dextrins derived therefrom, starch ethers and esters, amyloses, cellulose ethers and carboxymethyl celluloses. Polymerization may be carried out by gradually adding the ester and persulphate to a solution of the polysaccharide. The polymeric product thus formed contains unchanged polysaccharide, polymeric ester and graft copolymers in which the ester chains are grafted on to the polysaccharide. The dispersions are used for sizing man-made fibres and yarns.ALSO:Man-made fibres and yarns, e.g. those derived from nylon, polyethylene terephthalate, polyacrylonitrile, cellulose esters and regenerated cellulose, are sized prior to knitting with a stable aqueous polymeric dispersion obtained by polymerizing, with the aid of a persulphate catalyst, acrylic or methacrylic esters in an aqueous medium in the presence of a water-soluble polysaccharide present in the proportion of 10 to 300 per cent by weight of the ester. Esters specified are methyl, ethyl and butyl acrylates and methyl, beta-ethoxyethyl and butyl methacrylates. Polysaccharides specified are maize, wheat or sago starch or the dextrins derived therefrom, starch ethers and esters, amyloses, cellulose ethers and carboxymethyl celluloses. The polymeric component of the compositions consists of unchanged polysaccharide, polymeric ester and graft copolymers in which the ester chains are grafted on to the polysaccharide. The composition may also include a plasticizer, agent to assist moisture uptake, antistatic agent or a lubricant.