Abstract: A tire comprises a rubber composition based on at least one elastomeric matrix mainly comprising a random copolymer comprising ethylene units and conjugated diene units, the mole fraction of the ethylene units in the copolymer being within a range extending from 50% to 95%; a peroxide; and a specific acrylate derivative.

Abstract: An object of the present invention is to provide a golf ball travelling a great flight distance on driver shots on a rainy day or the like and having excellent spin performance on approach shots. The present invention provides a golf ball comprising a golf ball body and a paint film covering the golf ball body and composed of at least one layer, wherein an outermost layer of the paint film is formed from a paint containing a curable silicone resin, a curing catalyst, and a reactive silicone oil.

Abstract: The present invention relates to a cross-linkable rubber composition, a cross-linked rubber composition obtained by cross-linking such a rubber composition, a method of preparing a tyre and a tyre. In a cross-linkable rubber composition the cross-linkable rubber composition comprises, per hundred parts by weight of rubber (phr): ?1 phr to ?99 phr of a rubber component selected from the group of styrene-butadiene rubber (SBR), polybutadiene rubber (BR), natural rubber (NR) or a mixture thereof; and ?1 phr to ?120 phr of an aliphatic resin component. The composition further comprises ?1 phr to ?50 phr of a polyisoprene rubber (IR) having ?mol-%, as determined by NMR spectroscopy, of 3,4-linked units derived from isoprene.

Abstract: An object of the present invention is to provide a golf ball travelling a great flight distance on driver shots on a rainy day or the like and having excellent spin performance on approach shots. The present invention provides a golf ball comprising a golf ball body and a paint film covering the golf ball body and composed of at least one layer, wherein an outermost layer of the paint film is formed from a paint containing a curable silicone resin, a curing catalyst, and a reactive silicone oil.

Abstract: Disclosed herein are a functionalized diene monomer-containing polymer containing first and second functionalizing groups, processes for preparing the functionalized polymer, and rubber compositions containing the functionalized polymer. The functionalized polymer contains polymer chains comprises of at least one conjugated diene monomer optionally in combination with at least one vinyl aromatic monomer wherein each polymer chain is functionalized at its chain end with at least the first functionalizing group and is coupled via the first functionalizing group to the second functionalizing group.

Abstract: Disclosed herein are a functionalized diene monomer-containing polymer containing first and second functionalizing groups, processes for preparing the functionalized polymer, and rubber compositions containing the functionalized polymer. The functionalized polymer contains polymer chains comprises of at least one conjugated diene monomer optionally in combination with at least one vinyl aromatic monomer wherein each polymer chain is functionalized at its chain end with at least the first functionalizing group and is coupled via the first functionalizing group to the second functionalizing group.

Abstract: A foam rubber molded produce obtained by molding a rubber composition containing 100 parts by mass of ethylene-?-olefin-nonconjugated diene copolymer, 4 to 30 parts by mass of amorphous 4-methyl-1-pentene copolymer, 2 to 8 parts by mass of blowing agent, and a sulfur-based vulcanizing agent, and having a Mooney viscosity after kneading (ML1+4, 100° C.) of 54 or less. A specific gravity is 0.3 to 0.8, a compression set is less than 27%, and a foam state is an interconnected cell.

Abstract: The polymer of the present invention is a synthesized polyisoprene or an isoprene copolymer. The polymer has a number average molecular weight (Mn) of 1.5 million or more when measured by using gel permeation chromatography (GPC).

Abstract: Disclosed are a modified conjugated diene polymer and a method for preparing the same. Provided are advantageously a modified conjugated diene polymer and a method for preparing the same which provide superior compatibility with an inorganic filler, heat generation, tensile strength and abrasion resistance, low fuel consumption and excellent resistance on wet roads.

Abstract: A condom comprises natural rubber and polyurethane. Preferably, the condom has a single wall thickness of less than 55 ?m. More preferably the condom has a single wall thickness of less than 55 ?m and a burst pressure of 1.0 kPa or above. A process for making the condom comprises mixing polyurethane and natural rubber latex and forming a condom therefrom.

Abstract: This invention relates to preparation and use of in situ functionalized elastomers in a rubber composition, namely post polymerization functionalization of elastomers, in rubber compositions containing precipitated silica filler reinforcement and tires having components thereof.

Abstract: An air spring bellow comprising a vulcanized rubber component including the at least partially vulcanized residue of EPDM and a rubber other than EPDM.

Abstract: The invention concerns a method of devulcanising vulcanised rubber which comprises the following steps: a) providing at least one vulcanised rubber composition; b) grinding the vulcanised rubber into chips or pellets; c) mixing the ground rubber obtained from step b) in such a way as to homogenise the form and temperature of same. d) carrying out a non-degrading mechanical treatment on the mixed rubber at the end of step c) to obtain a polymeric composite. The invention also concerns a thermoplastic material and an elastomeric mixture which comprise, in the formulation of same, at least one polymeric composite obtained by this method of devulcanisation.

Abstract: An elastomer composition includes guayule rubber and a butadiene rubber, with at least about 5 phr guayule rubber based on 100 phr elastomer. The cured rubber has a higher coefficient of friction as compared to a cured rubber of the same formulation except using Hevea rubber rather than guayule rubber.

Abstract: The present invention provides a functional diene polymer, a preparation method thereof and a rubber composition comprising the functional diene polymer. The functional diene polymer comprises at least one type of conjugated diene structural units and silane coupler functional units represented by formula (I) in its molecular chain, and the number-average molecular weight of the functional diene polymer is 50,000˜1,000,000; R1-R4 are C1-C20 linear or branched alkyl or heteroatom-containing C1-C20 linear or branched alkyl, and the heteroatom is selected from one or more of halogen, oxygen, sulfur, silicon, and phosphorus. Not only the relationship between the wet slip resistance and the rolling resistance of the functional diene polymer is effectively improved, but also the offensive odor produced in the rubber mixing process owing to the addition of the silane coupler is reduced.

Abstract: The subject invention is directed towards tire components which are comprised of rubber compositions which are comprised of (1) about 2 phr to about 45 phr of a trans-1,4-isoprene-butadiene copolymer which has about 4 weight percent to about 16 weight percent butadiene repeat units and from about 84 weight percent to about 96 weight percent isoprene repeat units, wherein the trans-1,4-isoprene-butadiene copolymer has a Mooney ML 1+4 viscosity which is within the range of about 35 to about 80; and (2) about 55 phr to about 98 phr of at least one other elastomer, preferably a diene based elastomer. The most preferred tire components are those which contain cord reinforcements and require adequate green strength to enhance the tire building and shaping process to maintain cord integrity in the final cured tire.

Abstract: A process and the resultant product from the process for continuously making a blend of a terpolymer and a tetrapolymer utilizing ethylene, propylene, and non-conjugated dienes. This process allows for the creation of products with high diene contents and broad molecular weight distributions while utilizing a continuous flow reactor and a known catalyst. The process allows for these products to be made without gelling or fouling of the reactor, which are problems known in the art.

Abstract: A precursor to an elastomeric composition with improved properties is disclosed. The precursor comprises a cross-linkable rubber, a thermoplastic vulcanizate, and a cross-linking agent. An elastomeric composition produced by cross-linking of the rubber in the precursor and methods for manufacture of the precursor and the elastomeric composition are disclosed as well.

Abstract: A pressure-sensitive adhesive composition contains a butyl rubber. The pressure-sensitive adhesive composition has a shear storage elastic modulus G? at ?10° C. of 1.0×106 Pa or less and a shear storage elastic modulus G? at 60° C. of 2.0×104 Pa or more obtained by dynamic viscoelasticity measurement of the pressure-sensitive adhesive composition under the conditions of a frequency of 1 Hz, a temperature rising rate of 5° C./min, and a temperature range of ?60 to 70° C.

Abstract: The present invention provides a rubber composition for a sidewall or base tread, which offers good flex crack growth resistance, crack initiation resistance, durability, and fuel economy despite the use of a softener derived from non-petroleum resources; and also provides a pneumatic tire formed from the rubber composition. The present invention relates to a rubber composition for a sidewall or base tread, containing a rubber component including at least two kinds of diene rubbers, and a myrcene polymer, wherein the rubber component includes at least one kind of diene rubber selected from the group consisting of natural rubber, epoxidized natural rubber, and butadiene rubber, and the myrcene polymer has a weight average molecular weight of 1000 to 500000.

Abstract: The present invention relates to a branched conjugated diene copolymer which is useful for preparing a rubber composition, having high uniformity of a temperature dependence curve of a viscoelasticity tan ?, for a tire, a rubber composition comprising the copolymer, and a pneumatic tire produced using the rubber composition for a tire. The branched conjugated diene copolymer is composed of monomer components comprising a branched conjugated diene compound represented by a general formula (1): wherein R1 represents an aliphatic hydrocarbon group having 6 to 11 carbon atoms, and an aromatic vinyl compound represented by a general formula (2): wherein R2 represents an aromatic hydrocarbon group having 6 to 10 carbon atoms, and R5 represents a hydrogen atom or the like, and a copolymerization ratio (m) of the aromatic vinyl compound (2) is 45% by mass or more.

Abstract: A pressure-sensitive adhesive composition includes 100 parts by mass of a rubber component containing 40 to 93 mass % of a butyl rubber and 7 to 60 mass % of a polyisobutylene and 82 to 128 parts by mass of a softener having a kinetic viscosity at 40° C. of 100 to 9000 mm2/s.

Abstract: The invention provides a composition comprising a first composition comprising the following: A) a first ethylene/?-olefin interpolymer that has a weight average molecular weight (Mw) greater than 90,000 g/mole and a MWD less than, or equal to 3, each as determined by conventional GPC; B) a second ethylene/?-olefin interpolymer; and wherein the first composition has a number average molecular weight (Mn) less than 10,000 g/mole, as determined by conventional GPC; and wherein the ?-olefin of first interpolymer is the same as the ?-olefin of the second interpolymer.

Abstract: The present invention relates to a branched conjugated diene copolymer which is useful for preparing a rubber composition, having high uniformity of a temperature dependence curve of a viscoelasticity tan ?, for a tire, a rubber composition comprising the copolymer, and a pneumatic tire produced using the rubber composition for a tire. The branched conjugated diene copolymer is composed of monomer components comprising a branched conjugated diene compound represented by a general formula (1): wherein R1 represents an aliphatic hydrocarbon group having 6 to 11 carbon atoms, and an aromatic vinyl compound represented by a general formula (2): wherein R2 represents an aromatic hydrocarbon group having 6 to 10 carbon atoms, and R5 represents a hydrogen atom or the like, and a copolymerization ratio (m) of the aromatic vinyl compound (2) is 45% by mass or more.

Abstract: A crosslinked composition is obtained by crosslinking a composition, containing: 1 to 99 parts by mass of a vinyl aromatic copolymer rubber (I) comprising 5 to 70% by mass of a vinyl aromatic monomer unit and 0.1 to 30% by mass of a conjugated diene monomer unit and having one or more tan ? peak temperatures between 75° C. and 125° C.; 99 to 1 parts by mass of an ethylenic copolymer rubber (II); 10 to 100 parts by mass of an olefinic resin (III) based on 100 parts by mass of a total amount of the vinyl aromatic copolymer rubber (I) and the ethylenic copolymer rubber (II); and 0.01 to 50 parts by mass of a crosslinking agent (IV) based on 100 parts by mass of the total amount of the vinyl aromatic copolymer rubber (I) and the ethylenic copolymer rubber (II).

Abstract: The present invention provides a rubber composition for tires which achieves a balanced improvement in rolling resistance, abrasion resistance, and wet-skid performance while providing excellent processability; and a pneumatic tire including the rubber composition. The present invention relates to a rubber composition for tires, including: a modified diene rubber A which has been terminally modified with a specific acrylamide compound; a modified diene rubber B which has been modified with a silicon or tin compound and a specific modifying compound or with the modifying compound; and a silane coupling agent containing a mercapto group, the modified diene rubbers A and B, taken as a whole, having a weight average molecular weight falling within a specific range.

Abstract: The present invention provides a tire rubber composition with which the grip performance, the abrasion resistance, and the performance in terms of rolling resistance are improved in a balanced manner. The present invention relates to a tire rubber composition comprising: a modified diene rubber A which is modified with a specific acrylamide compound; and a modified diene rubber B which is modified with a specific modifying compound alone or together with a specific silicon or tin compound, a weight average molecular weight of a total of the modified diene rubbers A and B being 300,000 to 1,400,000.

Abstract: A rubber composition contains a higher ethylene content EPDM and a lower ethylene content EPDM as a rubber component. The proportion of the higher ethylene content EPDM is 30 to 80 mass % based on the overall amount of the rubber component. The rubber composition is less susceptible to reduction in friction coefficient ? and has a proper hardness, a smaller permanent elongation and an excellent abrasion resistance after crosslinking. Therefore, the rubber composition is suitable for a sheet conveying roller and an image forming apparatus incorporating the sheet conveying roller.

Abstract: Provided is a studless winter tire which provides good performance on ice and snow and good abrasion resistance, and suffers little change in hardness and little discoloration on the tire surface. The present invention relates to a studless winter tire including a tread formed from a rubber composition containing a predetermined amount of a farnesene resin obtained by polymerizing farnesene. The present invention relates to a studless winter tire including a tread formed from a rubber composition containing a predetermined amount of at least one myrcene resin selected from the group consisting of myrcene polymers with a Mw of 1,000-500,000, myrcene-butadiene copolymers with a Mw of 1,000-500,000, and myrcene-styrene copolymers with a Mw of 1,000-150,000; and a predetermined amount of a silica with an N2SA of 40-400 m2/g, the rubber component containing a predetermined amount of a high-cis polybutadiene with a cis content of 95% by mass or more.

Abstract: Disclosed is an ethylene-propylene-diene terpolymer having isotactic polypropylene crystallinity compounded with a blend rubber wherein the terpolymer can be present in an amount effective to improve tack, aged tensile strength retention, fatigue resistance, ozone cracking resistance, and reversion resistance. Also disclosed is an elastomer composition wherein the terpolymer can have at least 60 wt % propylene-derived units, at least 6 wt % ethylene-derived units and from 0.3 to 10 wt % diene-derived units, and a tire sidewall composition comprising from 10 to 30 phr terpolymer, from 20 to 60 phr natural rubber, from 20 to 60 phr polybutadiene rubber, and an optional secondary blend rubber. Also disclosed is a vulcanizate of the elastomer composition, and articles, tire sidewalls, tires, retreaded tires, bias truck tires, off-road tires, and passenger automobile tires made with the vulcanizate. Further disclosed are processes for making molded articles and tires, and for retreading tires.

Abstract: The invention relates to the field of producing synthetic rubbers, in particular diene (co)polymers, such as polybutadiene, polyisoprene and styrene-butadiene rubber (SBR), which can be used in the production of tyres and industrial rubber articles, in the modification of bitumens, in electrical engineering and in other fields. The method consists of a polymerization process or a copolymerization process which is carried out in two parallel reactors, and each of dienes are polymerized or copolymerized with each other and/or with arylvinyl compounds, wherein an organolithium initiator, an electron donor additive and a branching agent are fed into the first reactor, and an organo lithium initiator, an electron donor additive and a functionalizing agent are fed into the second reactor, and the resultant polymerized mixtures are subsequently mixed with each other.

Abstract: Curable elastomer compositions are described which include particles of reclaimed elastomeric material having a particle size of 60 mesh or smaller, sulfur and one or more accelerators, wherein the ratio by weight of the one or more accelerators to sulfur in the composition is at least 1:1. Curable styrene butadiene rubber (SBR) elastomer compositions are also described which include reclaimed elastomeric material, sulfur and one or more accelerators, wherein the ratio by weight of the one or more accelerators to sulfur in the composition is at least 1:1. The cured elastomeric compositions exhibit improved physical properties compared to elastomer compositions containing reclaim material which employ conventional high sulfur cure systems.

Abstract: Disclosed are water-soluble nanoparticles. The water-soluble nanoparticles are each surrounded by a multifunctional group ligand including an adhesive region, a cross linking region, and a reactive region. In the water-soluble nanoparticles, the cross-linking region of the multifunctional group ligand is cross-linked with another cross-linking region of a neighboring multifunctional group ligand.

Abstract: The present invention is directed to a peroxide curable rubber compound containing a butyl rubber polymer, an olefin polymer of ethylene, at least one ?-olefin and optionally at least one diene, and a high vinyl polybutadiene polymer. The present invention is also directed to a peroxide curable rubber compound containing a butyl polymer, an EP(D)M rubber polymer, and a 1,2-polybutadiene polymer.

Abstract: The invention relates to a rubber composition having better workability and fracture resistance than the prior art, and more specifically, to a rubber composition containing a polymer (B) obtained from an emulsion-polymerized polymer latex (A) having a number average molecular weight in the range of 1,000-130,000.

Abstract: Highly branched compositions including: (i) from about 96 wt % to about 99.9 wt % metallocene catalyzed ethylene propylene diene derived units; and (ii) from about 0.1 wt % to about 4 wt % multifunctional monomer derived units, wherein the highly branched composition has: (a) a Mooney viscosity ML (1+4) at 125° C. of about 30 to 100 MU, (b) a Mooney relaxation area MLRA of about 100 to about 1000, (c) a branching index, g?(vis) of less than about 0.9, (d) a phase angle, ?, of less than about 55 degrees at a complex modulus of 10 kPa, measured at 190° C., and (e) a degree of shear thinning greater than about 0.95, measured at 190° C., are disclosed herein. Homogeneous blends including this composition are also described. Processes to make the highly branched composition and the homogeneous blend are also described herein.

Abstract: The present invention provides a copolymer of a conjugated diene compound and a non-conjugated olefin that is used for manufacturing a rubber excellent in crack growth resistance, heat resistance and ozone resistance and that includes a cis-1,4 bond at a unit derived from the conjugated diene compound, a rubber composition containing the copolymer, a rubber composition for tire treads using the rubber composition for tire tread members, a crosslinked rubber composition obtained by crosslinking the rubber composition, and a tire using the rubber composition or the crosslinked rubber composition. In the copolymer of a conjugated diene compound and a non-conjugated olefin, the cis-1,4 bond content of a unit derived from the conjugated diene compound is more than 92%.

Abstract: The present invention provides a copolymer of a conjugated diene compound and a non-conjugated olefin that is used for manufacturing rubber excellent in low heat generation properties, heat resistance, ozone resistance (weather resistance), a rubber composition containing the copolymer, a crosslinked rubber composition obtained by crosslinking the rubber composition, and a tire manufactured by using the rubber composition or the crosslinked rubber composition. In the copolymer of a conjugated diene compound and a non-conjugated olefin, the content of 1,2 adduct units (including 3,4 adduct units) of a unit derived from the conjugated diene compound is 5% or less.

Abstract: The present invention provides a rubber composition that is used for manufacturing a rubber excellent in weather resistance, fracture resistance and crack growth resistance, and that contains a conjugated diene compound/non-conjugated olefin copolymer, a conjugate diene-based polymer and a non-conjugated diene compound/non-conjugated olefin copolymer, a rubber composition for tire side use using the rubber composition for tire sidewall members, a crosslinked rubber composition obtained by crosslinking the rubber composition, and a tire. The rubber composition includes: (A) a conjugated diene compound/non-conjugated olefin copolymer containing a conjugated diene compound-derived unit by at least 40 mol %; (B) a conjugated diene-based polymer; and (C) a non-conjugated diene compound/non-conjugated olefin copolymer containing an ethylene-propylene-diene rubber.

Abstract: A composition comprising at least the following components: (A) a first composition comprising the following: i) a first interpolymer comprising, in polymerized form, ethylene, an ?-olefin, and a nonconjugated polyene; ii) a second interpolymer comprising, in polymerized form, ethylene, an ?-olefin and a nonconjugated polyene; and wherein the first composition has an MWD less than, or equal to, 3.5, a Mooney Viscosity (ML (1+4 @125° C.)) greater than, or equal to, 80, and an [(ML(1+4 @125° C.))/Mw(conv)]*1000 greater than 0.429 mole/g; (B) a thermoplastic polymer; and (C) a vulcanization agent is provided. A crosslinked composition made by heating one or more of the inventive compositions is also provided. Articles made from one or more of the inventive compositions are also provided.

Abstract: Pneumatic rubber tire with a component comprised of a silica reinforced rubber composition comprised of specialized polybutadiene rubber, functionalized styrene/butadiene elastomer and cis 1,4-polyisoprene rubber.

Abstract: The invention relates to a functionalized diene elastomer composed: a) of a diene elastomer functionalized, at the chain end or in the middle of the chain, by a tin functional group, exhibiting a monomodal distribution of molecular weights before functionalization and a polydispersity index before functionalization of less than or equal to 1.3, b) of a diene elastomer star-branched with a tin compound, exhibiting a monomodal distribution of molecular weights before star-branching and a polydispersity index before star-branching of less than or equal to 1.3, and c) of a content of less than 15% by weight, with respect to the total weight of the functionalized diene elastomer, of a non-tin-functional diene elastomer, the said diene elastomers a), b) and c) being, before optional functionalization or optional star-branching, the same in nature.

Abstract: The present invention describes a composition comprising a diene-based rubber and at least one cyclo-aliphatic epoxide-based polyether or polyglycol ether. The present invention also describes a composition comprising at least one extending oil and at least one cyclo-aliphatic epoxide-based polyether or polyglycol ether, wherein the at least one extending oil is selected from the group consisting of an aromatic oil, an aliphatic oil, a naphthenic oil, and mixtures thereof.

Abstract: This invention relates to a pneumatic tire with an outer, running surface containing, circumferential tread comprised of a styrene/butadiene (SBR) rich rubber composition containing two SBR's with spaced apart glass transition temperatures (Tg's), one of which is a functionalized SBR with a functional group reactive with hydroxyl groups on a precipitated silica, together with a combination of at least three resins with spaced apart softening points. The filler reinforcement is a combination of precipitated silica and specialized rubber reinforcing carbon black.

Abstract: The copolymer rubber composition comprises 60 to 75% by weight of a copolymer rubber (1) and 40 to 25% by weight of a copolymer rubber (2), and [iodine value of the copolymer rubber (1)?iodine value of the copolymer rubber (2)] is 5 to 30. The copolymer rubber (1) is an ethylene-?-olefin-nonconjugated polyene copolymer rubber having an ethylene unit of 50 mol % to 70 mol %, an ?-olefin unit of 50 mol % to 30 mol %, and an iodine value of 15 to 45, and the copolymer rubber (2) is an ethylene-?-olefinic copolymer rubber having an ethylene unit of more than 70 mol % and 95 mol % or less, an ?-olefin unit of less than 30 mol % and 5 mol % or more, and an iodine value of 10 to 30.

Abstract: Aqueous adhesive containing, based on solid contents, ?20 to 80% by weight of an (meth)acrylic copolymer (A) as dispersion in water, ?10 to 50% by weight of a resin (B), ?5 to 30% by weight of a reaction product (C) of i) 20 to 50% based on dispersion (C) of an (meth)acrylic copolymer having an acidic number of 1-100 mg KOH/g in form of a dispersion, ii) 5 to 40% based on dispersion (C) of at least one sugar alcohol with a MN of 100 to 600 g/mol, and reacting the mixture in alkaline solution for 0.1 to 6 hours, and 0.1 to 30% by weight of one or more auxiliaries (D) wherein the sum A to D adds to 100%.

Abstract: The present invention provides a tire rubber composition with which the grip performance, the abrasion resistance, and the performance in terms of rolling resistance are improved in a balanced manner. The present invention relates to a tire rubber composition comprising: a modified diene rubber A which is modified with a specific acrylamide compound; and a modified diene rubber B which is modified with a specific modifying compound alone or together with a specific silicon or tin compound, a weight average molecular weight of a total of the modified diene rubbers A and B being 300,000 to 1,400,000.

Abstract: Elastomer compositions comprising uncured elastomer and reclaimed elastomer are described. In one embodiment, the compositions comprise reclaimed elastomer material (micronized rubber powder) of broad particle size distribution, which is less expensive than traditional reclaimed elastomer material with narrow particle size distribution. Further, compositions comprising reclaimed elastomer materials with broad particle size distribution perform comparably to those comprising reclaimed elastomer materials with narrow particle size distribution. In other embodiments, the compositions comprise both vulcanized and devulcanized elastomer materials. Advantageously, by using a combination of vulcanized and devulcanized material, it is possible to incorporate a greater percentage by weight of reclaimed material in to an elastomer composition, thus providing additional cost savings while maintaining high levels of mechanical properties.

Abstract: Disclosed are a polybutadiene having a controlled microstructure, a narrow molecular weight distribution, minimal gel content, and a low APHA color, a modified polybutadiene, producing methods for both, and a rubber-reinforced styrene resin composition using the same. The polybutadiene of the present invention is characterised in that the ratio (Tcp/ML1+4) of a 5% toluene melting viscosity (Tcp) measured at 25° C. and the Mooney viscosity (ML1+4) at 100° C. is 2.0 or higher, the molecular weight distribution (Mw/Mn) is 2.80 or less, the gel content is 0.06 wt % or less, and the APHA color is 20 or less.

Abstract: A power transmission belt is provided with a peroxide-cured, polybutadiene-based elastomeric composition. The elastomeric composition includes 100 parts of a rubber derived from 50 to 100 parts by weight of polybutadiene rubber; 0 to 50 parts by weight of at least one other rubber; about 1 to about 20 parts by weight per 100 parts by weight of total rubber (phr) of a type I coagent; about 1 to about 20 phr of a type II coagent; and about 0.1 to about 10 phr of a peroxide curing agent.