STYROL / BUTADIENE-GROPFCOPOLYMERISATE LATEX AND THIS CONTAINING AS A REINFORCING LATEX, WHICH CAN BE VULCANIZED IN THE HEAT FOR THE PRODUCTION OF LATEX FOAM

摘要

1. A styrene/butadiene graft copolymer latex obtained by emulsion polymerization in the presence of 1 to 6% by weight of a conventional fat soap and/or resin soap as emulsifier and = 0.3% by weight of a conventional molecular weight regulator for the polymer, each percentage being based on the total monomers, and characterized by the following features : a) the emulsion polymerization is carried out by a semi-continuous emulsion-feed process ; b) the graft copolymer is composed of 35 to 65% by weight of the graft base (A) which in turn is composed of the graft base (A1) and the grafted-on component (A1), and 35 to 65% by weight of component (B) grafted on in the final step ; c) the graft base (A) is obtained in two polymerization steps ; in the first step, a polystyrene nucleating latex is obtained whose solid (A1) is 1 to 20% by weight, based on the graft copolymer ; the component (A2) of the graft base (A), which is grafted on in the second step, is composed of 86 to 95% by weight of repeating units which are obtained by polymerization of styrene, and 5 to 14% by weight of repeating units which are obtained by polymerization of 1,3-butadiene ; feeding of the emulsifier during grafting being accompanied by intensive stirring in order to avoid the formation of new particles ; d) the component (B) of the graft copolymer, which is grafted on in the final step, is composed of 62 to 70% by weight of repeating units which are obtained by polymerization of styrene, and 30 to 38% by weight of repeating units which are obtained by polymerization of 1,3-butadiene ; feeding of the emulsifier during grafting being accompanied by intensive stirring in order to avoid the formation of new particles : e) the parameters in the preparation of the graft copolymer latex are selected such that the latex particles have an average diameter, determined by surface titration, of 120 to 300 nm.