Abstract: In a process for the production of pulverulent, tack-free, pourable, filler-containing elastomer particles by precipitating a stable, emulsified, homogeneous mixture of an aqueous elastomer emulsion and an aqueous dispersion of a solid filler for said elastomer in the presence of sodium silicate to form an aqueous suspension of the precipitated elastomer and the filler, the improvement which comprises:(a) precipitating the silicic acid in the aqueous suspension at a pH of 4.0 to 9.0, and then(b) mixing the thus-produced suspension of elastomer, filler and precipitated silicic acid with additional filler in the form of an emulsifier-free aqueous suspension.

Abstract: The properties of elastomeric vulcanizates are improved by compounding an elastomer prior to vulcanization with a polydodecenamer reinforcing resin derived from cyclododecene and cyclododecadiene and vulcanizing the compounded elastomer.

Abstract: Homopolymers of butadiene having a vinyl content which varies substantially and decreasingly along the longitudinal axis of the macromolecule toward an end thereof are produced by conducting an organolithium-Lewis base catalyzed polymerization at a substantially constantly increasing polymerization temperature throughout the polymerization.

Abstract: Discrete, finely divided, tack-free elastomer particles are prepared from a filler-containing aqueous elastomer emulsion containing an aqueous emulsion of an elastomer dissolved in a volatile inert organic solvent having an emulsifying amount of a quaternary ammonium salt cationic surfactant and an aqueous suspension or dispersion of a solid, finely divided elastomer filler, which process comprises gradually introducing the filler-containing aqueous elastomer emulsion into an aqueous alkali silicate solution while maintaining said solution at a pH greater than 2 and simultaneously evaporating the organic solvent to form discrete, finely divided, tack-free elastomer particles.The process can be applied to solid elastomers or to post-polymerization elastomer solutions, and is particularly suitable for preparing pourable, carbon black containing elastomer particles to be formed into shaped objects.

Abstract: High molecular weight polybutadiene, polyisoprene and other hydrocarbon polymers having a high vinyl and a low 1,4-trans-double bond content, which are useful in the manufacture of tire treads and carcasses, are produced employing as catalyst system (a) a cobalt compound; (b) a halogen-containing organoaluminum compound; and (c) a tris-(aryl) phosphite of the formula P--(OR.sub.1), (--OR.sub.2),--OR.sub.3 wherein R.sub.1, R.sub.2 and R.sub.3 are monocyclic halogenated aryl, or diaryl, naphthyl, anthracenyl or phenanthryl or the corresponding halogenated and/or alkylated polycyclic aryl; and optionally (d) an H-acidic compound, e.g., water.

Abstract: A process for the manufacture of a pourable, pulverulent rubber-filler mixture containing plasticiser oil, by combining a filler containing plasticiser oil with an aqueous emulsion of a rubber solution, and precipitating and drying the mixture, wherein the plasticiser oil is adsorptively bound on the finely divided active filler in an amount of from 1 to 100 parts by weight, relative to 100 parts by weight of the filler, the premix thus obtained, which continues to be free-flowing and pulverulent, and consists of filler charged with plasticiser oil, is dispersed in water in the presence of an emulsifier, the resulting dispersion is intimately mixed with an aqueous emulsion of a synthetic rubber solution, this mixture is introduced into an aqueous precipitation bath which is at a temperature of from 40 to 95.degree.

Abstract: For facilitating the production of automotive tire treads of satisfactory abrasion and skid resistance, there is provided a composition consisting essentially of:A. a polybutadiene containing 25-50% of monomer units arranged in the 1,2-position; 10-40% of 1,4-cis-double bonds; 15-55% of 1,4-trans-double bonds; and an ML-4 value of 40-120;B. 5-100 parts by weight of a plasticizer oil; andC. 30-120 parts by weight of a carbon black.