Patent ID: 6034173
Filing Date: 2000-03-07
Classification: C08F

Abstract:
A process for the preparation of (co)polychloroprene latexes by the homopolymerization of chloroprene in a water emulsion and/or the copolymerization of mixtures of chloroprene and up to 50% by weight of other copolymerizable monomers, in the presence of at least one radical initiator and an emulsifying system which comprises:(a) at least one non-carboxylated ionic surface-active agent (Ea1); and(b) at least two non-ionic surface-active agents (Eb1) and (Eb2) which have HLB values differing by 3 or more units,said process comprising the steps of:(A) preparing a water emulsion comprising:(i) a fraction f.sub.1 of a composition of (co)monomers/polymers having a polymer content of between 0 and 100% by dry weight of the composition; and(ii) an emulsifying system which comprises:(1) the non-carboxylated ionic emulsifying agent (Ea1) in a quantity of between 10 and 50% by weight of the total quantity of (Ea1) used in the process and in a quantity from 0.4 to 1.0 parts by weight, based on a total quantity of 100 parts by weight of (co)monomers;(2) the non-ionic emulsifying agent (Eb1) having the lower HLB value, in a quantity of between 2 and 30% by weight of the total quantity of (Eb1) used in the process and in a quantity from 0.1 to 1.0 parts by weight, based on a total quantity of 100 parts by weight of (co)monomers; and(3) the non-ionic emulsifying agent (Eb2) having the higher HLB value, in a quantity of between 0 and 25% by weight of the total quantity of (Eb2) used in the process and in a quantity from 0 to 0.5 parts by weight, based on a total quantity of 100 parts by weight of (co)monomers,(B) introducing a remaining fraction f.sub.2 (f.sub.1 +f.sub.2 =100 parts by weight) of said composition of (co)monomers/polymers and the rest of the emulsifying system into the water emulsion of step (A) to enable the polymerization to develop, wherein the total quantity of the emulsifying system used in the process comprises, based on a total quantity of 100 parts by weight of (co)monomers:(i) from 0.6 to 3 parts by weight of (Ea1);(ii) from 0.5 to 4 parts by weight of (Eb1); and(iii) from 0.5 to 4 parts by weight of (Eb2).