Abstract: A tire tread made for polydiene rubber crosslinked with 1,2-bis(N,N-dibenzylthiocarbamoyldisulfido)ethane and method of producing the same.

Abstract: Polysulfide compounds and vulcanization compositions containing the polysulfide compounds, for use in vulcanizing rubbers, are disclosed, with the polysulfide compounds being of the formula ##STR1## wherein R.sup.1 -R.sup.4 are each, independently, hydrogen or C.sub.1 -C.sub.4 alkyl and n is 2 to 10wherein the polysulfide compounds can be used alone or in a vulcanization composition containing the polysulfide compound, sulfur, one or more additional accelerators, one or more basic compounds and, optionally, conventional rubber additives, to provide vulcanized products with improved reversion stability and ageing stability.

Abstract: Polysulfide derivatives, having the general formula (A--S--S--).sub.2 X--S--S--A processes for their production and their use for crosslinking of reversion-stable rubber vulcanizates are provided. Crosslinking with reduced reversion and loss of elastomeric properties with age is achieved by the crosslinking system provided by the invention.

Abstract: Vulcanization of diene rubbers at a temperature of from 140.degree. to 200.degree. C. in the presence of 1 to 4.5 parts of a crosslinker having the formula ##STR1## wherein n denotes 2 or 6 and Bz denotes benzyl, in the simultaneous presence of a very small amount of sulfur and a small amount of a mercapto or sulfenamide accelerator or mixtures thereof affords elastomers having a previously unachieved outstanding ageing stability and reversion stability, after relatively short vulcanization times using economical amounts of chemicals while avoiding blooming phenomena in the vulcanizate.

Abstract: Polysulfide derivatives having the general formula (A--S--S--).sub.2 X--S--S--A, processes for their production and their use for crosslinking of reversion-stable rubber vulcanizates are provided. Crosslinking with reduced reversion and loss of elastomeric properties with age is achieved by the crosslinking system provided by the invention.

Abstract: An unsaturated, elastomeric, asymmetrically coupled block copolymer of the formula:(A--B).sub.n --X--(B).sub.m,wherein block A is a block of polybutadiene having an 8 to 60% content of uniformly distributed vinyl groups and block B is a homopolymer of isoprene or a copolymer of at leat 10% isoprene units with 0 to 60% butadiene units and up to 45% styrene units and X is a radical of a coupling agent, and (m-n).gtoreq.0 while (m+n) ranges from 3 to 25.

Abstract: Rubber mixtures for tire treads are found, which show an improved wet skid resistance coupled with balanced abrasion and rolling resistance properties. This is achieved by rubber blend mixtures which contain 3,4-polyisoprene having a 3,4-content from 55 to 75%, a glass transition temperature from 0.degree. to -25.degree. C., a number average molecular weight of 200,000 and higher and an inhomogeneity U of less than 1.8. Motor vehicle tires can be prepared in an advantageous manner with these rubber mixtures.

Abstract: An unsaturated, elastomeric ABC block copolymer comprised of the monomer units of 40 to 80% of 1,3-butadiene, 5 to 40% of isoprene and 2 to 30% of styrene, said copolymer comprising i) 40 to 75% of block A which contains styrene and butadiene units or isoprene and butadiene units with a content of distributed vinyl or isopropenyl groups of less than 15%, iia) up to 25% of a block B which contains styrene and butadiene units or isoprene and butadiene units with a vinyl or isopropenyl content of more than 70%, or iib) up to 25% of a block B' which contains styrene, isoprene and optionally butadiene units with a content of homogeneously distributed isopropenyl or vinyl groups of less than 15%, and iii) 20 to 55% of a block C which contains styrene and isoprene units and optionally butadiene units with an isopropenyl or vinyl content of more than 70%.

Abstract: An unsaturated elastomeric, asymmetrically coupled block copolymer of the formula: (A).sub.n -X-(B).sub.m, wherein block A is a block of polybutadiene having a content of uniformly distributed vinyl groups ranging from 8 to 60% and block (B) is a homopolymer of isoprene or a copolymer of at least 10% isoprene with 0 to 60% butadiene and up to 45% styrene, the copolymer having a vinyl unit content of 75 to 90%, X is a radical of a coupling agent and (m-n).gtoreq.0 and (m+n) ranges from 3 to 25.

Abstract: An unsaturated elastomeric AB block copolymer comprising 20-75 wt. % 1,3-butadiene monomer units; 5-50 wt. % isoprene monomer units; and 3-30% wt. % styrene monomer units; wherein said block copolymer contains less than 3 wt. % styrene blocks, each of said block A and block B contain all three of said monomer units, said copolymer comprises 30-90 wt. % of block A and 70-10 wt. % of block B, and wherein the average vinyl and isopropenyl content of block B are each at least 30% higher than those of block A; and a method for preparing the unsaturated AB block copolymer.

Abstract: A block-free polymer is prepared by anionically polymerizing at least two compounds selected from the groups consisting of butadiene, isoprene and styrene in an inert organic solvent in the presence of an organolithium compound as a catalyst and a cocatalyst of a glycol dialkyl ether: ##STR1## wherein R.sub.3 is hydrogen, methyl or ethyl, R.sub.1 and R.sub.2 are alkyl groups of different numbers of carbon atoms selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, sec-butyl and t-butyl, and the total number of carbon atoms in the alkyl group ranges from 5 to 7.

Abstract: An unsaturated elastomeric AB block copolymer, comprising:(i) 45-85 wt. % 1,3-butadiene,(ii) 5-40 wt. % isoprene, and(iii) up to 30 wt. % styrene,wherein said AB block copolymer comprising:40-80 wt. % of a block A, said block A comprising butadiene monomer units and having a content of uniformly distributed vinyl groups of 8-60 wt. %, and60-20 wt. % of a block B, said block B comprising 0-60 wt. % 1,3-butadiene, at least 10 wt. % isoprene and up to 45 wt. % styrene monomer units, wherein the butadiene and isoprene monomer units have a vinyl group content of 75-90 wt. %.

Abstract: Polyisoprenes having a high content of 1,2- and 3,4-structural units, a process for their preparation, and their use.The previous processes for the preparation of polyisoprene having a high content of 1,2- and 3,4-structural units were still unsatisfactory in terms of the cocatalyst employed.The use of ethylene glycol dialkyl ethers of the formulaR.sub.1 --O--CH.sub.2 --CH.sub.2 --O--R.sub.2in which R.sub.1 and R.sub.2 are alkyl groups having different numbers of C atoms, from the group consisting of methyl, ethyl, n- and isopropyl and n-, iso-, sec.- and tert.-butyl, has, in particular, the advantage that the "living polymers" formed during the anionic polymerization are not damaged.The production of tires and damping elements using these polyisoprenes.

Abstract: ABC block copolymers on the basis of butadiene, isoprene and optionally styrene, are provided by a polymerization process wherein the resultant block copolymer comprises:about 40 to 75 wt % of a block A based on butadiene (uniformly distributed vinyl group content less than about 15 wt %),up to about 25 wt % of a block B based on butadiene and isoprene (vinyl content less than about 15 wt %) or based on butadiene (vinyl content more than about 75 wt %)about 20 to 55 wt % of a block C based on butadiene and isoprene (vinyl content more than about 75 wt %). The ABC block copolymers are useful for the production of tire treads.

Abstract: Tire treads having(a) low heat buildup under dynamic stress and a low frictional resistance to rolling,(b) adequate damping and accordingly a high wet skid resistance,(c) high abrasion resistance and accordingly high wearing efficiency, are produced from vulcanizable compositions based on an elastomer component containing an isoprene polymer characterized by a high content of recurring units obtained by 1,2- and 3,4-polymerization of isoprene.

Abstract: The invention relates to hot-vulcanizable tread strips which are produced from novel vulcanizable compositions and from which the treads of pneumatic motor tires can be produced. The vulcanizable compositions are based on a rubber component which includes a special, novel rubber component based on isoprene.The inventive tire treads have an excellent combination of useful properties which can be described by the following set of characteristics:(a) High flexibility of low temperatures, i.e., the elastic rubber state is retained even at temperatures below -30.degree. C. (i.e., good cold-weather properties);(b) High vibration-damping over a wide temperature range, and thus good wet skid resistance (i.e., tread safety);(c) High wear-resistance, and thus long service life (i.e., economic advantages).The tire treads have good all-weather characteristics, and thus the tires may be used year-round.

Abstract: A process for the precipitation of a pulverulent filled rubber, which comprises mixing a rubber latex, a rubber solution or a rubber emulsion with a filler suspension, waterglass and a water-soluble aluminum salt at a predetermined pH value of 3.0-3.7, the pH value being kept constant by introduction of acid during the precipitation.

Abstract: Polybutadiene oils of 400-6,000 molecular weight, having double bonds which are 10 to 60% vinyl, 1 to 15% transvinylene and 25 to 85% cis-vinylene, and 3-20% by weight, corresponding to 0.4 to 3% by weight of bound silicon, of which are reactive silyl polymer units of the formula ##STR1## wherein X is a hydrolyzable group and Y and Z are the same as X or are H and/or alkyl of 1-8 carbon atoms, cycloalkyl of 5-12 carbon atoms, or optionally substituted phenyl; are useful as adhesion promoters for vulcanizable elastomer compositions comprising a mineral filler.

Abstract: Vulcanizable polyalkenamer molding compositions comprising: (a) a polyoctenamer having an extensively cyclic structure with a trans-content of 50-70% and a reduced specific viscosity of 0.8-1.7 (dl./g.); and (b) conventional elastomer vulcanizing agents and additives have improved flow properties suitable for thermoplastic molding techniques together with mechanical properties in the vulcanizate comparable to SBR rubber.

Abstract: Pourable elastomer-filler mixtures, optionally containing plasticizer oil, are prepared by an improved process, the process comprising mixing an aqueous emulsion of an elastomer solution with an aqueous dispersion of a filler(s); introducing this mixture into water containing a precipitant(s); precipitating the elastomer-filler mixture while simultaneously removing the elastomer solvent by distillation; separating the thus-precipitated elastomer-filler mixture from the water; and drying the elastomer mixture under constant agitation; and the improvement comprising:Initially emulsifying the elastomer solution in water in the presence of a combination of:(a) 0.01 - 1.0% by weight of an anionic emulsifier, based on the weight of the elastomer solution;(b) 0.001 - 0.1% by weight of a nonionic protective colloid, based on the weight of the elastomer solution; and(c) 0.001 - 0.