Abstract: A process of preparing a bimodal or multimodal homopolymer of a conjugated diene or a bimodal or multimodal copolymer of a conjugated diene with another conjugated diene or with a vinyl aromatic compound consists in polymerizing the monomer(s) in a reaction medium at a temperature of between 20.degree. C. and 200.degree. C. in the presence of a catalytic system comprising an organolithium initiator, a barium, strontium or calcium compound, and an organometallic compound of a metal of group 2B or 3A of the periodic classification of elements of the Mendeleev Table and adding hydrogen as a modifying agent to the reaction medium during the course of the polymerization reaction.

Abstract: A solid chlorinated polymer product having reduced residual solvent content is prepared by treatment of a solution thereof with steam or hot water in the presence of a separately prepared added chlorinated polymer having a second-order transition temperature at least 20.degree. below that of the chlorinated polymer product which would be obtained in the absence of the added chlorinated polymer.

Abstract: Rubbery, tacky polymer is mechanically subdivided in the presence of fine particles of substantially thermoplastic halogenated polymer.

Abstract: A process for preparing a rubber composition for tire treads having resilience, wet skid resistance and wear resistance well balanced with each other, by mechanically mixing a specific amount in total of a halogenated butyl rubber, natural rubber or a polyisoprene rubber and a polybutadiene rubber with a specific amount of carbon black and with other additives in the first mixing step and then mechanically mixing the resulting mixture with the remainder of the rubber ingredients and carbon black in the second mixing step thereby to obtain the rubber composition.

Abstract: A process of preparing a bimodal or multimodal homopolymer of a conjugated diene or a bimodal or multimodal copolymer of a conjugated diene with another conjugated diene or with a vinyl aromatic compound consists in polymerizing the monomer(s) in a reaction medium at a temperature of between 20.degree. C. and 200.degree. C. in the presence of a catalyst system comprising an organolithium initiator, a barium, strontium or calcium compound, and an organometallic compound of a metal of group 2B or 3A of the periodic classification of elements of the Mendeleev Table, and adding to the reaction medium during the course of the polymerization reaction a compound of a transition metal of groups 1B to 7B and 8 or a magnesium compound of the general formula Mg(A).sub.2.

Abstract: A process of preparing a bimodal or multimodal homopolymer of a conjugated diene or a bimodal or multimodal copolymer of a conjugated diene with another conjugated diene or with a vinyl aromatic compound consists in polymerizing the monomer(s) in a reaction medium at a temperature of between 20.degree. C. and 200.degree. C. in the presence of a catalyst system formed of the reaction product of:(a) an organic compound of a metal of group 3A of the periodic classification of elements of the Mendeleev Table having one of the following formulas:M.sup.1 M.sup.3 R.sup.1 R.sup.2 R.sup.3 R.sup.4M.sup.2 (M.sup.3 R.sup.1 R.sup.2 R.sup.3 R.sup.4).sub.2M.sup.3 R.sup.1 R.sup.2 R.sup.3M.sup.1 OM.sup.3 R.sup.1 R.sup.2with (b) at least one electron-donor compound containing at least one heteroatom,and adding hydrogen as a modifying agent to the reaction medium during the course of the polymerization reaction.

Abstract: An uncrosslinked thermoplastic elastomer composition comprising:(A) 35-95% by weight of a 1,2-polybutadiene having a 1,2-configuration content of 70% or more, a crystallinity of 5-40% by weight and [.eta.] of 0.7 dl/g or more as measured at 30.degree. C. in toluene,(B) 1-20% by weight of an isobutylene polymer or an isobutylene-isoprene copolymer (preferably having a degree of unsaturation of 0-5 mole % and a viscosity average molecular weight of 7,000-80,000),(C) 5-40% by weight of a polybutadiene rubber having a 1,4-configuration content of 80% or more and(D) 0-30% by weight, preferably 5-30% by weight, of at least one member selected from the group consisting of isoprene rubber, natural rubber, acrylonitrile-butadiene rubber, styrene-butadiene rubber and ethylene-propylene type rubbers, wherein, preferably, (B)/{(C)+(D)}=2/1-1/20.

Abstract: A rubber composition for tire treads having improved rolling resistance and wet road braking performance, comprising (I) a chlorinated butyl rubber and/or a brominated butyl rubber, (II) natural rubber and/or a polyisoprene rubber and, if desired, (III) a polybutadiene rubber in specific blending ratios.

Abstract: A process for preparing a tire tread rubber composition having improved rolling resistance and wet skid resistance comprising [I] 100 parts by weight of a rubber material composed of 25 to 75% by weight of substantially amorphous polybutadiene having a 1,2-bond unit content of 65 to 90 mole % and a Mooney viscosity (ML.sub.1+4, 100.degree. C.) of 20 to 100 and 75 to 25% by weight of natural rubber and/or cis-1,4-polyisoprene, and [II] 40 to 70 parts by weight of carbon black, said process comprising (1) mechanically compounding 40 to 60 parts by weight of the rubber material [I] with 40 to 70 parts by weight of carbon black [II], and then (2) adding to the resulting mixture the rubber material [I] in an amount sufficient to adjust the amount of the carbon black [II] to 40 to 70 parts by weight per 100 parts by weight of the rubber material [I] and mechanically compounding them.

Abstract: The green strength of SBR, SBR-polybutadiene, natural rubber or combinations thereof is improved by blending with an EPDM or EPM having a high degree of crystallinity.

Abstract: Rubber compositions comprising a blend of a major amount of polybutadiene having 1,2-addition in the range of about 25 to about 65 percent and a minor amount of polybutadiene having trans-1,4-addition of at least about 70 percent. Also vulcanized cellular rubber compositions in which the rubber comprises a blend of a major amount of polybutadiene having 1,2-addition in the range of about 25 to about 65 percent and a minor amount of polybutadiene having trans-1,4-addition of at least about 70 percent.

Abstract: A polybutadiene rubber composition comprising (A) a polybutadiene rubber obtained by solution polymerization and having a Mooney viscosity (ML.sub.1+4.sup.100.degree. C.) of 60-110 and a 1,4-configuration content of not less than 60%, preferably not less than 70%, and (B) a polybutadiene polymer obtained by solution polymerization and having a viscosity-average molecular weight of 20,000-140,000, preferably 40,000-100,000, and a 1,4-configuration content of not less than 60%, preferably not less than 70%, in which composition the weight ratio of (A)/(B) is 100/5-100/150, preferably 100/35-100/100, and the Mooney viscosity (ML.sub.1+4.sup.100.degree. C.) of which composition is 20-70. This composition is high in tackiness in the unvulcanized state and also excellent in the physical properties of vulcanizate.

Abstract: A thick-cord lightweight tire body having an improved fatigue life is disclosed. The tire body comprises a bias-structured carcass composed of rubberized plies each including thick organic fiber cords and rubber interposed between the carcass plies. The rubber has a thickness corresponding to hm/ho.ltoreq.0.5, where hm is an average rubber gauge between the plies at a center position in a widthwise direction of tire and, ho is a diameter of the thick cord, and is a rubber composition consisting essentially of 100 parts by weight of a rubber component and 50-70 parts by weight of carbon black. The rubber component is a mixture of 60-95 parts by weight of a rubber and 5-40 parts by weight of a liquid polymer having a viscosity-average molecular weight of 3.times.10.sup.4 -10.times.10.sup.4. The rubber composition has a dynamic modulus of elasticity E' at 100.degree. C. under 2% elongation given by E'.gtoreq.6.0.times.10.sup.7 dyne/cm.sup.2, a dynamic loss angle tan .delta. given by tan .delta..ltoreq.0.

Abstract: The invention relates to elastomer composites which can be used for pneumatic tire sidewalls. Such composite particularly comprises a manipulated blend of (A) a hexadiene polymer, (B) high unsaturation rubber, and optionally, (C) a low unsaturation rubber. The sidewall composition particularly enhances the adhesion of the sidewall to the tire carcass stock.

Abstract: A pneumatic tire having a cap/base structured tread and having an improved resistance against heat build-up and an improved wear resistance at the end of the use can be obtained by forming a tread base rubber of the tire with a vulcanizate of a rubber composition comprising specifically limited amounts of short fibers of syndiotactic-1,2-polybutadiene having a maximum diameter of not more than 10.mu. and an average diameter of less than 1.mu., carbon black, sulfur and natural or synthetic rubber.

Abstract: Radial tires having improved irregular wear resistance, which are reinforced with a belt cord layer and a carcass cord layer, characterized in that as the embedding rubber of the belt cord layer, use is made of natural rubber, polyisoprene rubber or a blend rubber consisting of said rubber and less than 30 parts by weight of at least one of polybutadiene rubber and styrene-butadiene copolymer rubber and that for the ground contact area of the tread of tire, a rubber composition consisting of 100 parts by weight of styrene-butadiene copolymer rubber having a viscosity average molecular weight of not less than 2.times.10.sup.5 or a blend rubber consisting of more than 50 parts by weight of said copolymer rubber and at least one of natural rubber, polyisoprene rubber and polybutadiene rubber, 5-60 parts by weight of at least one of a liquid styrene-butadiene copolymer, a liquid polyisoprene polymer and a liquid polybutadiene polymer having a viscosity average molecular weight of 5.times.10.sup.3 -7.times.10.sup.

Abstract: A particular carbon black in a medium vinyl polybutadiene composition gives a vulcanizable rubber composition with superior blowout resistance, low heat buildup, and good resilience after vulcanizing. Such a carbon black in blends of medium vinyl polybutadiene and natural rubber provides a vulcanizable rubber composition having good dynamic wire cord adhesion (as measured by time to failure).

Abstract: A pneumatic tire having an improved chipping resistant property is disclosed. In the tire, the tread portion is formed with a vulcanizate of a rubber composition comprising 3-40 parts by weight of short fibers of syndiotactic-1,2-polybutadiene, 30-100 parts by weight of carbon black and 0.2-5 parts by weight of a p-phenylenediamine type antioxidant, on a basis of 100 parts by weight of a rubber selected from natural rubber, synthetic rubber and a blend thereof in an optional blending ratio.

Abstract: Syntactic foam compositions are manufactured by heat-curing, in the presence of a free radical generator, a mixture comprising a resin and hollow spheres; the resin consists of(a) 10 to 100% of polybutadiene with 20-95% 1,2 units, 5-60% thereof being in a carbocyclic cyclized form, its number average molecular weight being at most 100,000;(b) 0 to 90% of polybutadiene with 40-98% 1, 2 units and 2-60% 1, 4 units, its number average molecular weight being at most 100,000; and(c) 0 to 90% of a polymerizable liquid vinyl monomer.

Abstract: A rubber composition and a process for the preparation of rubber compositions comprising, in the presence of a metal oxide, vulcanizing, or vulcanizing after blending with another unsaturated rubber, of the reaction product of (1) an unsaturated rubber, sulfur and a sulfur cleaving agent, (2) an unsaturated rubber and a mercaptan compound, (3) a halogenated unsaturated rubber and a metal salt of a sulfur cleaving agent, or (4) an unsaturated rubber, a sulfur cleaving agent and a compound having a functional group such as a nitrile oxide, a nitroso or a thionylamine.

Abstract: The invention relates to elastomer composites which can be used for pneumatic tire sidewalls. Such composite particularly comprises a manipulated blend of (A) a hexadiene polymer, (B) high unsaturation rubber, and optionally, (C) a low unsaturation rubber. The sidewall composition particularly enhances the adhesion of the sidewall to the tire carcass stock.

Abstract: A rubber composition for the tread of tire having reduced rolling resistance and increased wet skid resistance with the mechanical properties unimpaired, said rubber composition comprising 20 to 80% by weight of (I) essentially amorphous polybutadiene having a 1,2-bond units content of at least 70% and a Mooney viscosity (ML.sub.1+4, 100.degree. C.) of 10 to 100; 10 to 75% by weight of (II) polybutadiene rubber having a 1,2-bond units content of 20% or less and a Mooney viscosity (ML.sub.1+4, 100.degree. C.) of 20 to 130; and 3 to 35% by weight of (III) at least one rubber selected from styrene/butadiene copolymer rubber having a bound styrene content of 15 to 25% by weight, natural rubber, and polyisoprene rubber having a cis-1,4-bond units content of at least 90%.

Abstract: An improved method is provided for processing of rubbers in which one of the rubbers is a synthetic green strength polymer, the improvement being the addition of the synthetic green strength polymer at the second stage of mixing rather than at the prior art first stage. The method can be used for preparing rubber compounds whenever a synthetic green strength polymer is used as one component of the rubber compound.

Abstract: A heterogeneous blend of elastomers having a stabilized morphology, as well as the method of making the same, comprises at least two radiation cross-linkable elastomers which form a heterogeneous blend. The radiation cross-linkable elastomer components are selected from the class consisting of conjugated dienes having from 4 to 12 carbon atoms, natural rubber, polyalkenamers such as polypentenamer, chlorinated polyolefinic elastomers having from 2 to 8 carbon atoms such as chlorinated polyethylene, ethylenepropylene terpolymers, polysiloxanes, nitrile rubber, butadiene-acrylic copolymers, chlorosulfonated polyethylene, butadiene vinyl pyridine copolymers, substituted phosphazenes, aliphatic polyesters which are substantially non-crystalline and have 6 carbon atoms or more in the repeating unit, preferably from 6 to 12 carbon atoms, butyl copolymers containing groups with unsaturation, a butadiene-styrene copolymer and a copolymer, terpolymer, etc.

Abstract: A novel rubber composition is obtained by blending a rubber mixture consisting of 15 to 50 parts by weight of 1,2-polybutadiene having a 1,2-addition unit content of 70% or more, a crystallinity of 5 to 40% and an intrinsic viscosity [.eta.] of 0.7 dl/g or more (as measured in toluene at 30.degree. C.) and 85 to 50 parts by weight of at least one rubber selected from the group consisting of natural rubber and diene-based rubbers with 3 to 10 parts by weight of sulfur per 100 parts by weight of said rubber mixture. Said rubber composition has a desirable processability and exhibits, on curing, high hardness, high modulus, low temperature dependency of physical properties, low heat generation and excellent blow-out resistance. It is suitable as a rubber material for use in various low profile automobile tires such as radial tires.

Abstract: Extrusion coating compositions for woven and non-woven polyolefin substrates are disclosed which employ an ethylene-propylene-diene terpolymer rubber, a high density polyethylene, and ethylene-propylene block copolymer and an ethylene-isobutylacrylate copolymer. Optionally, ultraviolet stabilizers, flame retardants and pigments can be added to each. Also disclosed are woven and non-woven polyolefin substrates which are coated with the above-cited extrusion coating compositions.

Abstract: A rubber composition and a process for the preparation of rubber compositions comprising, in the presence of a metal oxide, vulcanizing, or vulcanizing after blending with another unsaturated rubber, of the reaction product of (1) an unsaturated rubber, sulfur and a sulfur cleaving agent, (2) an unsaturated rubber and a mercaptan compound, (3) a halogenated unsaturated rubber and a metal salt of a sulfur cleaving agent, or (4) an unsaturated rubber, a sulfur cleaving agent and a compound having a functional group such as a nitrile oxide, a nitroso or a thionylamine.

Abstract: A reactive polyolefin composition comprising a polyolefin and a rubber component dispersed in the polyolefin in fine granular form, at least a portion of the particles of the rubber component containing at least one type of polymer having a functional group in the molecular structure thereof, a molding thereof and a process for producing the same, are disclosed.

Abstract: Disclosed is a process for producing fiber-reinforced elastic articles comprising: 1 to 20 parts by weight of 1,2-polybutadiene fibrils dispersed in a matrix of 100 parts by weight of a rubber material. In the process, the 1,2-polybutadiene in the form of particles are dispersed in the matrix of rubber material; the dispersion is extruded through a die at a temperature of at least 5.degree. C. above the melting point of 1,2-polybutadiene, but not exceeding 240.degree. C., to convert the particles of 1,2-polybutadiene into fibrils; the extruded dispersion is rolled by means of a pair of rollers to increase the degree of molecular orientation of the 1,2-polybutadiene fibrils, and; a composition comprising an elastic material matrix, the 1,2-polybutadiene fibrils dispersed in the elastic material matrix and a vulcanizing agent is shaped and vulcanized at an elevated temperature.

Abstract: The green strength of elastomers is improved by the addition of semi-crystalline butene polymers selected from the class consisting of polybutene and interpolymers made from 1-butene monomer and at least one monomer selected from the class consisting of alpha-olefins, non-conjugated dienes, and non-conjugated polyenes. The semi-crystalline butene polymer is mixed with a desired elastomer such as natural or synthetic cis-1,4-polyisopropene, or a synthetic elastomer made from monomers selected from the class consisting of conjugated dienes having from 4 to 10 carbon atoms, interpolymers of said dienes among themselves or with vinyl substituted aromatic hydrocarbon compounds having from 8 to 12 carbon atoms, or polyalkenylenes. The mixing or blending of the butene polymer and the elastomer may be through conventional methods such as cement mixing or mastication.

Abstract: Disclosed is a process of producing a fiber-reinforced rubber article having excellent mechanical strength and modulus of elasticity, and exhibiting rubber-like elasticity, by providing a rubber composition from a vulcanizable rubber material, a vulcanizing agent and 1,2-polybutadiene staple fibers in an amount of 1 to 20 parts by weight per 100 parts by weight of the rubber material, shaping and vulcanizing the rubber composition to provide a shaped, vulcanized article in which surface portions of said 1,2-polybutadiene staple fibers are vulcanized and cross-linked to the vulcanized rubber material matrix.

Abstract: A pneumatic rubber tire having a tread comprised of a blend of cis-1,4 polyisoprene rubber and a medium vinyl polybutadiene rubber cured with an excess of sulfur. Said tire has been found to be useful as an aircraft tire having tread of enhanced durability.