Abstract: Rubber mixtures containing so-called "pre-crosslinked" polychloroprene give vulcanizates having an improved combination of low rolling resistance and low abrasion.

Abstract: Vulcanizates of polychloroprene materials containing fluorinated polyolefin have a decreased rebound elasticity without having a significantly adverse effect on the mechanical properties.

Abstract: The combination of unmodified resinic acids and direct peptization in the production of sulfur-modified polychloroprene leads to a favorable ratio of elasticity to viscosity.

Abstract: Toluene-soluble, sulphur-modified polychloroprene is obtained by emulsion copolymerization of chloroprene, sulphur and optionally further monomers which are copolymerizable with chloroprene and sulphur using a peroxy activator and subsequent working-up by stabilizing, stopping, degassing and isolating without separate peptization, in that polymerization is carried out in the presence of dithiocarbamates and/or xanthogenates and the activator is metered in continuously or batch-wise during the course of polymerization.

Abstract: The invention relates to a polychloroprene rubber which shows advantages over the prior art in the sum total of its performance properties, namely vulcanization rate, tensile strength, elongation at break, modulus, tear propagation resistance and thermal stability of the vulcanizate.

Abstract: Storage-stable polychloroprene is obtained, using a polymerization initiator comprising a mixture of(1) a redox system comprising(a) a reducing agent selected from the group consisting of(i) sodium dithionite,(ii) formamidine sulphinic acid, and(iii) a mixture from (i) and (ii),(b) potassium peroxodisulphate as an oxidizing agent and, optionally,(2) sodium anthraquinone-.beta.-sulphonate as a co-activatorin the presence of oxygen, wherein from 10 to 90 by weight of the initiator are present at the commencement of polymerization and the remainder is added during the polymerization, and after a certain degree of conversion the reducing agent is the only component of redox system (1) which remains to be added.

Abstract: An improved process for the preparation of polychloroprene by the emulsion (co)polymerization of chloroprene and optionally other monomers capable of copolymerization with chloroprene, using a peroxo activator, and subsequent working up of the product by stopping the reaction, stabilizing, degassing and isolating the product, characterized in that polymerization is carried out in the presence of dithiocarbamates and/or xanthates and 0 to 0.5% by weight of sodium .beta.-anthraquinone sulphonate.

Abstract: Gel-free polychloroprene is obtained, at high monomer conversions, using a polymerization initiator comprising sodium dithionite or a mixture of sodium dithionite with formamidinesulphinic acid or with potassium peroxydisulphate or with formamidinesulphinic acid and potassium peroxodisulphate or with potassium peroxodisulphate and sodium anthraquinon-.beta.-sulphonate or with formamidinesulphinic acid and potassium peroxodisulphate and sodium anthraquinone-.beta.-sulphonate, and in the presence of oxygen and a chain transfer agent when 30 to 90% of the initiator is present at the commencement of polymerization and the remainder is added in portions during the polymerization, only further sodium dithionite being added at a conversion >60% in the case of an initiator combination, and when 20 to 80% by weight of the total amount of chain transfer agents is present before or at the commencement of polymerization and the remaining amount is added in one or more parts at monomer conversions of greater than 20%.

Abstract: An elastomeric mass of polychloroprene sol and polychloroprene gel in proportions in the range of 95:5 to 25:75% by weight in which the polychloroprene sol is free from sulphur and the polychloroprene gel used is a sulphur-containing gel with xanthate or carbamate functions has better processing characteristics than the pure sol component without the expected deterioration in the mechanical properties of the vulcanisates prepared from the mass.

Abstract: An improved process of polymerizing an aqueous emulsion of chloroprene monomer stabilized with phenothiazine wherein polymerization is initiated in the presence of phenothiazine stabilizer and molecular oxygen with a polymerization initiator comprising sodium dithionite.