Abstract: A rubber formulation including (a) a hydrogenated nitrile rubber, (b) an organopolysiloxane, (c) a cross-linking controller selected from (i) an ester or polyester of acrylic or methacrylic acid with a polyhydric alcohol, (ii) an amide or polyamide of acrylic or methacrylic acid with a polyamine, (iii) an alkoxysilane having a C.dbd.C double bond, an amino group or a mercapto group and (iv) triallyl isocyanate, (d) an optional filler, and (e) a peroxide crosslinking agent. The rubber formulation is prepared by mixing together (a') a hydrogenated nitrile rubber composition having added therein an optional filler, (b') an organopolysiloxane composition having added therein an optional filler, and (c) the crosslinking controller, and thereafter adding (e) the peroxide crosslinking agent.

Abstract: Polychloroprene polymers having stable viscosities and good scorch resistance, as well as excellent mechanical and dynamic properties in vulcanized state, are prepared by polymerizing chloroprene in alkaline aqueous emulsion, in the presence of a free-radical initiator and a combination chain-transfer agent including (1) at least one xanthogen disulfide and (2) at least one bis(acylaminophenyl)polysulfide.

Abstract: A polychloroprene of sol type, the latices and solutions of which are gel free, exhibit improved rheological and other properties and are useful in the formulation of adhesive compositions, is readily prepared by polymerizing chloroprene in aqueous emulsion in the presence of X and Y chain transfer agents, said X chain transfer agent being present upon initiation of the polymerization and having a relative reaction velocity greater than that of chloroprene, and said Y chain transfer agent being incrementally or continuously added to the polymerization reaction medium over the course of the polymerization reaction and having a relative reaction velocity essentially the same as that of chloroprene.

Abstract: Chloroprene is polymerized in an alkaline aqueous emulsion, containing a sulfonamide. The presence of the sulfonamide provides polychloroprene latices which are stabilized against aging.

Abstract: Sulfur-modified polychloroprene in alkaline aqueous emulsion is prepared by incorporating one or more organic polysulfides which act as peptizing agents during the polymerization of the chloroprene. The sulfur-modified polychloroprenes obtained have stable viscosities.

Abstract: Homogeneous free-running powders, mixable when dry and with a mean particle size of between 0.1 and 5 mm, are obtained by high-temperature flocculation in the presence of aluminum polyhydroxychloride salts. The temperature is preferably between 70.degree. and 100.degree. C. and the pH is preferably 6 to 13.

Abstract: Polymerization of chloroprene in an alkaline aqueous emulsion provides an improved latex by adding a specific amide to the emulsion, the amide being insoluble in water, soluble in the chloroprene and not being hydrolyzed by NaOH. The presence of an amide of this type makes it possible to obtain polychloroprene latices stabilized against ageing.

Abstract: A process for instantaneous peptization of polychloroprene latexes made by polymerizing in the presence of sulfur and a modifying agent such as iodoform or a dialkylxanthogen disulfide, by adding a suitable thiol at a pH at least equal to 9.

Abstract: Sulfur-modified polychloroprene in alkaline aqueous emulsion is prepared by incorporating one or more organic polysulfides which act as peptizing agents during the polymerization of the chloroprene. The sulfur-modified polychloroprenes obtained have stable viscosities.