The renewed rubber of this invention can be used in rubber formulations that are used in manufacturing a wide array of rubber products, including tires, power transmission belts, conveyor belts, hoses, and a wide array of other products. The present invention more specifically discloses a method for manufacturing an environmentally friendly, chemically functionalized, renewed rubber composition having a highly desirable combination of physical properties and which exhibits excellent processability comprising the steps of (1) blending a micronized rubber powder with a processing aid and a chemical functionalizing agent to produce a blended mixture; (2) processing the blended mixture under conditions of high shear and low temperature to produce a reacted mixture; (3) adding a stabilizer to the reacted mixture to produce the chemically functionalized renewed rubber composition.

Provided is a rubber composition which contains a diene rubber and a reinforcing filler, and the diene rubber contains a styrene-butadiene copolymer component including at least one type of styrene-butadiene copolymer and satisfying the following requirements: (1) the bonded styrene content is from 5 to 50 wt. %; (2) among components obtained by ozone decomposition, a content of a decomposed component V1 containing one 1,2-bonded butadiene-derived unit out of a total of 100 mol % of decomposed components containing styrene-derived units and/or 1,2-bonded butadiene-derived units is not less than 25 mol %; (3) among components obtained by ozone decomposition, a content of a decomposed component S2V1 containing two styrene-derived units and one 1,2-bonded butadiene-derived unit out of a total of 100 mol % of decomposed components containing styrene-derived units and/or 1,2-bonded butadiene-derived units is less than 5 mol %; and (4) a vinyl content of a butadiene moiety is not less than 50%.

A devulcanizing additive for vulcanized elastomers is described, said additive having improved efficiency and selectivity, together with the relative method of devulcaniztion, in continuous and batchwise, and the devulcanized product obtained by means of said devulcaniztion method of vulcanized elastomers.

Provided is a thermal decomposition method of used rubber that has excellent yields of isoprene and limonene without reducing the efficiency of thermal decomposition. The method is a method of thermally decomposing used rubber, including bringing the used rubber into contact with or swelling the used rubber in a medium, where the medium has a SP value of 8.3 (cal/cm.sup.3).sup.1/2 to 11 (cal/cm.sup.3).sup.1/2 and an endothermic peak temperature of 235? C. or higher measured by thermogravimetry (TGA), and the medium is liquid at 150? C., and then performing thermal decomposition.

Provided is a thermal decomposition method of used rubber that has excellent yields of isoprene and limonene without reducing the efficiency of thermal decomposition. The method is a method of thermally decomposing used rubber, including bringing the used rubber into contact with or swelling the used rubber in a medium, where the medium has a SP value of 8.3 (cal/cm.sup.3).sup.1/2 to 11 (cal/cm.sup.3).sup.1/2 and an endothermic peak temperature of 235? C. or higher measured by thermogravimetry (TGA), and the medium is liquid at 150? C., and then performing thermal decomposition.

Provided is a method by which a crosslinking site of a crosslinked elastomer can easily be returned to a non-crosslinked state. The method of returning a crosslinking site of a crosslinked elastomer to a non-crosslinked state includes a step of causing contact of a crosslinked elastomer including a diboronic acid ester skeleton unit represented by a specific general formula (1) at a crosslinking site with a monoboronic acid compound represented by a specific general formula (3) in the presence of an organic solvent having an SP value (solubility parameter) of not less than 7 (cal/cm.sup.3).sup.1/2 and not more than 10 (cal/cm.sup.3).sup.1/2. In this step, a molar abundance ratio of the monoboronic acid compound relative to the diboronic acid ester skeleton unit (monoboronic acid compound/diboronic acid ester skeleton unit) is set as more than 2 and not more than 5.

Provided is a method by which a crosslinking site of a crosslinked elastomer can easily be returned to a non-crosslinked state. The method of returning a crosslinking site of a crosslinked elastomer to a non-crosslinked state includes a step of causing contact of a crosslinked elastomer including a diboronic acid ester skeleton unit represented by a specific general formula (1) at a crosslinking site with a monoboronic acid compound represented by a specific general formula (3) in the presence of an organic solvent having an SP value (solubility parameter) of not less than 7 (cal/cm.sup.3).sup.1/2 and not more than 10 (cal/cm.sup.3).sup.1/2. In this step, a molar abundance ratio of the monoboronic acid compound relative to the diboronic acid ester skeleton unit (monoboronic acid compound/diboronic acid ester skeleton unit) is set as more than 2 and not more than 5.

A method for producing devulcanized rubber and an apparatus (100) therefor. The method for producing devulcanized rubber comprises the steps of (1) providing vulcanized rubber particles with a pre-determined particle size and (2) devulcanizing the vulcanized rubber particles. The vulcanized rubber particles are devulcanized mechanically by impact forces and devulcanized chemically by a chemical composition. The impact forces break sulphur-sulphur and sulphur-carbon bonds of the vulcanized rubber particles causing surfaces of the rubber to become receptive in reacting with the chemical composition and the chemical composition renders the sulphur passive to prevent reattachment of the bonds, of which the chemical composition comprises at least one accelerator, at least one inorganic activator and at least one organic activator.

A method for producing devulcanized rubber and an apparatus (100) therefor. The method for producing devulcanized rubber comprises the steps of (1) providing vulcanized rubber particles with a pre-determined particle size and (2) devulcanizing the vulcanized rubber particles. The vulcanized rubber particles are devulcanized mechanically by impact forces and devulcanized chemically by a chemical composition. The impact forces break sulphur-sulphur and sulphur-carbon bonds of the vulcanized rubber particles causing surfaces of the rubber to become receptive in reacting with the chemical composition and the chemical composition renders the sulphur passive to prevent reattachment of the bonds, of which the chemical composition comprises at least one accelerator, at least one inorganic activator and at least one organic activator.

Vulcanizable polymer compositions based on backbone-functionalized polydienes having the general formula (I): ##STR00001##