Abstract: The invention provides a flame-retardant rubber composition which may form a vulcanizate of an elastomer whose deterioration of mechanical strength is little to enjoy excellent mechanical properties, even when a nonhalogenated flame retardant is contained in a high proportion in the composition, and a flame-retardant elastomer obtained therefrom. The flame-retardant rubber composition contains (A) an olefin copolymer having a functional group, which comprises (a-1) a structural unit derived from ethylene, (a-2) a structural unit derived from an &agr;-olefin compound having 3 to 10 carbon atoms, (a-3) a structural unit derived from a functional group-containing unsaturated compound, and optionally (a-4) a structural unit derived from a nonconjugated diene compound, and has an intrinsic viscosity [&eegr;] of 0.1 to 10 dL/g as measured in decalin at 135° C., (B) a vulcanizing agent and/or a crosslinking agent and (C) a nonhalogenated flame retardant.

Abstract: A rubber composition comprising (a) a low molecular weight copolymer rubber which is an ethylene/&agr;-olefin/non-conjugated diene copolymer rubber having a limiting viscosity [&eegr;] of 0.4-1.6 dl/g measured in decalin at 135° C., and an ethylene content of 40-60 wt % and (b) a high molecular weight copolymer rubber which is an ethylene/&agr;-olefin/non-conjugated diene copolymer rubber having a Mooney viscosity (ML1+4,100° C.) of 60-150, an ethylene content of 60-80 wt %, and an iodine number of 5-35, wherein the difference between the iodine number of the low molecular weight copolymer rubber (a) and the iodine number of the high molecular weight copolymer rubber (b) is 5 or less and the ratio by weight of the low molecular weight copolymer rubber (a) and the high molecular weight copolymer rubber (b) is 50/50 to 80/20, the rubber composition having a Mooney viscosity (ML1+4,100° C.) of 20-50.

Abstract: The invention provides a flame-retardant rubber composition which may form a vulcanizate of an elastomer whose deterioration of mechanical strength is little to enjoy excellent mechanical properties, even when a nonhalogenated flame retardant is contained in a high proportion in the composition, and a flame-retardant elastomer obtained therefrom.

Abstract: A rubber composition comprising (a) a low molecular weight copolymer rubber which is an ethylene/&agr;-olefin/non-conjugated diene copolymer rubber having a limiting viscosity [&eegr;] of 0.4-1.6 dl/g measured in decalin at 135° C., and an ethylene content of 40-60 wt % and (b) a high molecular weight copolymer rubber which is an ethylene/&agr;-olefin/non-conjugated diene copolymer rubber having a Mooney viscosity (ML1+4,100° C.) of 60-150, an ethylene content of 60-80 wt %, and an iodine number of 5-35, wherein the difference between the iodine number of the low molecular weight copolymer rubber (a) and the iodine number of the high molecular weight copolymer rubber (b) is 5 or less and the ratio by weight of the low molecular weight copolymer rubber (a) and the high molecular weight copolymer rubber (b) is 50/50 to 80/20, the rubber composition having a Mooney viscosity (ML1+4,100° C.) of 20-50.

Abstract: A rubber composition exhibiting excellent low rolling resistance, high wet skid properties, and superior wear resistance, and suitably used as a vulcanized rubber for tire tread. The rubber composition comprises a styrene-butadiene copolymer previously extended using an extender oil, in an amount from 30 to 100 wt % of the total rubber components, and an extender oil in an amount from 6 to 50 parts by weight for 100 parts by weight of the total rubber components, of which 20 to 50 parts by weight of the extender oil for 100 parts by weight of styrene-butadiene copolymer is used to previously extend the styrene-butadiene copolymer. The styrene-butadiene copolymer has a styrene content from 5 to 45 wt %, 20 to 80% of a microstructure 1,2-bond of butadiene portion, a glass transition temperature from -55.degree. C. to -20.degree. C., and 40 wt % or more of a single styrene bond and 10 wt % or less of long styrene chain which contains 8 or more styrene molecules, among the total styrene bonds.

Abstract: An ethylene copolymer rubber composition which comprises an ethylene copolymer rubber and at least one member selected from the group consisting of a vulcanizing agent and a cross-linking agent and optionally a conjugated diene rubber, said ethylene copolymer rubber being composed of ethylene, an .alpha.-olefin having 3 to 12 carbon atoms, a non-conjugated diene represented by the following structural formula (I): ##STR1## wherein R.sup.1 and R.sup.2 represent independently hydrogen atoms or alkyl groups having 1 to 8 carbon atoms, R.sup.3 represents an alkyl group having 1 to 8 carbon atoms, and n is an integer of 2 to 10, and an .alpha.,.omega.-diene represented by the following structural formula (II) :CH.sub.2 .dbd.CH--(CH.sub.2).sub.m --CH.dbd.CH.sub.

Abstract: An ethylene-.alpha.-olefin-non-conjugated diene copolymer rubber composition comprising a low molecular weight component copolymer composed of an ethylene-.alpha.-olefin-non-conjugated diene copolymer having a Mooney viscosity (ML.sub.1+4, 100.degree. C.) of 10 to 150, an .alpha.-olefin content of 30 to 60% by weight and an iodine value of 37 to 65, and a high molecular weight component copolymer composed of an ethylene-.alpha.-olefin-non-conjugated diene copolymer having a Mooney viscosity (ML.sub.1+4, 100.degree. C.) of 100 to 500, an .alpha.-olefin content of 15 to 50% by weight and an iodine value of 3 to 15, the ratio of the iodine value of the low molecular weight component copolymer to the iodine value of the high molecular weight component copolymer being at least 4/1. The above composition can inhibit a gel from being produced during processing and achieve a high degree of cross-linking and is excellent in compression set, shape-retention and sponge surface skin.

Abstract: A rubber composition having an excellent wear resistance while holding proper hardness, modulus and the like as a vulcanizate comprises a blend of (A) styrene-diene copolymer rubber having specified content of bound styrene, glass transition temperature range and Mooney viscosity and (B) low molecular weight polymer having particular weight average molecular weight, wherein the blending ratio of the copolymer rubber (A) to the polymer (B) is 100 parts by weight to 10-120 parts by weight.

Abstract: Disclosure is herein made of a rubber composition containing at least 30% by weight of a butadiene copolymer which is characterized in that: (i) the content of vinyl bonds in a polybutadiene portion is from 40 to 70%; (ii) the content of bound vinyl aromatic compound is from 25 to 50% by weight: (iii) the ratio Mw/Mn between the weight average molecular weight (Mw) and the number average molecular weight (Mn) when calculated as polystyrene according to the gel permeation chromatograph (GPC) method is from 1.8 to 5, and the distribution of the molecular weight is unimodal; (iv) the rate of the copolymer having the weight average molecular weight of not more than 100,000 when calculated as polystyrene is from 10 to 30%; (v) the rate of the copolymer having the weight average molecular weight of not less than 2,000,000 when calculated as polystyrene is from 10 to 30%; and (vi) the Mooney viscosity (ML.sub.1+4 100.degree. C.) is from 20 to 100.

Abstract: A thermoplastic elastomer composition comprising (a) 20 to 70 parts by weight of a polyamide and (b) 80 to 30 parts by weight of a butyl rubber modified with a functional-group-containing compound having at least one group selected from a carboxyl group, an acid anhydride group and an epoxy group as the functional group, the total amount of the (a) and (b) components being 100 parts by weight. The thermoplastic elastomer composition is resistant to permeation of FREON gases containing hydrogen atom in their molecules and has excellent flexibility, low-temperature resistance and oil resistance.

Abstract: A rubber composition comprising 100 parts by weight of a rubber component which comprises at least 30% by weight of an emulsion polymerization rubber which is a conjugated diene polymer rubber or conjugated dienestyrene copolymer rubber obtained by emulsion polymerization, has a bound styrene content of 0-65% by weight, contains 20-35% by weight of a component having a molecular weight of not more than 150,000 as measured by a gel permeation chromatography and has a Mooney viscosity, ML.sub.1+4 (100.degree. C.), of 60-160 and a Mooney viscosity difference (.DELTA.MV) of -20 to +5 as defined by the following equation:.DELTA.MV=ML.sub.1+4 (100.degree. C.)-ML.sub.1+15 (100.degree. C.)and 45-200 parts by weight of carbon black. Said rubber composition is excellent in abrasion resistance, breaking strength and high histeresis property in uses in which carbon black or oil is blended at a high-filling rate.

Abstract: A process for producing a modified conjugated diene polymer which comprises the steps of (I) polymerizing a conjugated diene in an inert organic solvent in the presence of a catalyst comprising (a) a lanthanum series rare earth element compound, (b) an organoaluminum compound represented by the general formula, AlR.sup.1 R.sup.2 R.sup.3 (wherein R.sup.1, R.sup.2 and R.sup.3 which may be same or different, are hydrogen atoms or hydrocarbon groups of 1 to 8 carbon atoms and at least one of R.sup.1, R.sup.2 and R.sup.3 is said hydrocarbon group) and, if necessary, at least one member selected from the group consisting of (c) a Lewis acid and/or (d) a Lewis base, and then (II) modifying the resulting reactive polymer with a modifying compound of the general formula, R.sup.4.sub.n MX.sub.4-n (wherein R.sup.4 is an alkyl group of 1 to 20 carbon atoms or an aryl group, M is a tin atom, X is a halogen atom, and n is an integer of 1 to 3).

Abstract: A rubber composition is disclosed which contains not less than 20% by weight in a rubber component of a block copolymer composed of polymer or copolymer block units (A) and a random copolymer block units (B). The polymer or copolymer block units (A) are obtained by singly polymerizing a conjugated diolefine or copolymerizing the conjugated diolefine and a monovinyl aromatic hydrocarbon with use of a lithium initiator and contains not more than 10% by weight of the bound monovinyl aromatic hydrocarbon. The random copolymer block unit (B) are obtained by copolymerizing the conjugated diolefine and the monovinyl aromatic hydrocarbon and contain 15 to 80% by weight of the bound monovinyl aromatic hydrocarbon.

Abstract: A process for producing a modified conjugated diene polymer which comprises the steps of (I) polymerizing a conjugated diene in an inert organic solvent in the presence of a catalyst comprising (a) a lanthanum series rare earth element compound, (b) an organoaluminum compound represented by the general formula, Alr.sup.1 R.sup.2 R.sup.3 (wherein R.sup.1, R.sup.2 and R.sup.3 which may be same or different, are hydrogen atoms or hydrocarbon groups of 1 to 8 carbon atoms and at least one of R.sup.1, R.sup.2 and R.sup.3 is said hydrocarbon group) and, if necessary, at least one member selected from the group consisting of (c) a Lewis acid and/or (d) a Lewis base, and then (II) modifying the resulting reactive polymer with a modifying compound selected from the group consisting of the following components (e), (f) and (g): (e) an organometal halide compound represented by the general formula, R.sub.n .sup.4 MX.sub.4-n (wherein R.sup.

Abstract: A conjugated diene series rubber composition comprises, as a rubber component, (a) 20.about.100% by weight of a particular conjugated diene polymer and (b) a diene polymer rubber except for the polymer (a) and is excellent in the processability at unvulcanized state and the rebound resilience, strengths at rupture and wear resistance at vulcanized state.

Abstract: A butadiene-based rubber composition is disclosed, which contains not less than 20% by weight of a butadiene-based homopolymer or copolymer having a glass transition temperature (Tg) of not less than -105.degree. C., but less than -70.degree. C. and a Mooney viscosity (ML.sub.1+4, 100.degree. C.) of 10 to 150. The butadiene-based homopolymer or copolymer is obtained by polymerizing butadiene or random-copolymerizing butadiene with at least one kind of a monomer selected from the group consisting of another conjugated diene and an aromatic vinyl compound, and then reacting polymerization-active terminals thereof with an isocyanate compound and/or an isothiocyanate compound. The butadiene-based rubber composition has excellent resilience, fracture strength, and wear resistance as a vulcanizate as well as excellent processability as an unvulcanized rubber, and can be used as tire applications such as tire treads, undertreads, sidewalls, bead portions, etc.

Abstract: Disclosed herein is a rubber composition for use in vibration insulating material, which comprises as rubber components 5-50 parts by weight of a copolymer consisting of 99.5-45% by weight of a conjugated diolefin, 0.5-30% by weight of an ethylenically unsaturated carboxylic acid and 0-40% by weight of another vinly monomer polymerizable therewith, and 50-95 parts by weight of at least one rubber selected from natural rubber and synthetic diene rubbers. This rubber composition is excellent in the breaking properties and vibration insulating properties with a small temperature dependence of hysteresis loss.

Abstract: A rubber composition containing at least 20% by weight of a styrene-butadiene block copolymer consisting of a block (A) and a block (B) characterized in that: (i) the block (A) is a styrene-butadiene copolymer block having the content of styrene of 10-80% by weight and the average content of the vinyl bonds in the butadiene portion of 30-70% by weight; (ii) the block (B) is a polybutadiene block with the average content of the vinyl bonds in the butadiene portion being not more than 60% by weight (iii) the styrene-butadiene block copolymer contains at least 20% by weight of each of the block (A) and the block (B); (iv) the average content of the vinyl bonds in the butadiene portion of the block (A) is greater by at least 5% by weight than that of the block (B); (v) the glass transition temperature of the block (A) is higher by at least 30.degree. C.

Abstract: YA rubber composition for use in tire having improved rolling resistance, wet skid resistance and processability is disclosed, which comprises at least 20% by weight of a conjugated diolefin-vinyl-substituted aromatic hydrocarbon random copolymer. This random copolymer is produced by copolymerization with a particular initiator and coupling with a particular coupling agent, and has a content of vinyl-substituted aromatic hydrocarbon of 3-60% by weight, a content of tin bonded to copolymer of not less than 400 ppm and a Mooney viscosity (ML.sub.1+4.sup.100.degree.C.) of 20-200.

Abstract: A rubber composition containing not less than 20% of a conjugated diene based polymer or copolymer. The polymer or copolymer is obtained by polymerizing a conjugated diene or copolymerizing the conjugated diene with at least one kind of other conjugated diene and an aromatic vinyl compound with use of a lithium initiator, and then reacting an isocyanate compound with active terminals of the thus obtained polymer or copolymer. The conjugated diene is butadiene or isoprene, while other conjugated diene is selected from pentadiene, 2,3-dimethylbutadiene as well as isoprene and butadiene, and an aromatic vinyl compound may be styrene, vinyltoluene, .alpha.-methylstyrene, etc. The rubber composition is applicable as tread portion, carcass, side wall portion of tires, vibration resistant rubber, window frame, hose, and various industrial articles.