A latex of an acid-modified conjugated diene polymer including the acid-modified conjugated diene polymer obtained by modifying a conjugated diene polymer with an acid group-containing compound, in which a content of a structural unit derived from the acid group-containing compound is 0.2 to 0.7 parts by weight with respect to 100 parts by weight of the acid-modified conjugated diene polymer; a content of a water-soluble polymer in the latex is 2 parts by weight or less with respect to 100 parts by weight of the acid-modified conjugated diene polymer; when a solids content of the latex is adjusted to 60 wt %, a viscosity at 25° C. is 800 mPa.Math.s or less; and when the solids content of the latex is adjusted to 50 wt %, the viscosity at 25° C. is 300 mPa.Math.s or less.

A latex of an acid-modified conjugated diene polymer including the acid-modified conjugated diene polymer obtained by modifying a conjugated diene polymer with an acid group-containing compound, in which a content of a structural unit derived from the acid group-containing compound is 0.2 to 0.7 parts by weight with respect to 100 parts by weight of the acid-modified conjugated diene polymer; a content of a water-soluble polymer in the latex is 2 parts by weight or less with respect to 100 parts by weight of the acid-modified conjugated diene polymer; when a solids content of the latex is adjusted to 60 wt %, a viscosity at 25° C. is 800 mPa.Math.s or less; and when the solids content of the latex is adjusted to 50 wt %, the viscosity at 25° C. is 300 mPa.Math.s or less.

A rubber reinforcing filler and a method for preparing rubber reinforcing filler by activation and modification of coal gangue are provided. The method includes the following steps: providing coal gangue raw material; crushing coal gangue raw materials; the crushed coal gangue raw materials are ultrafine grinding to obtain coal gangue particles; coal gangue particles were obtained by air flow classification. Activation of coal gangue particles; the activated gangue particles were surface modified and ground to obtain the modified gangue particles. The invention relates to the field of comprehensive utilization of coal gangue and the technical field of rubber filler. The method is simple and effective, which can complete the blending modification of coupling agent and activated coal gangue particles for surface modification at low cost, so as to avoid the waste of materials in the traditional modification process and realize the preparation of high quality rubber reinforcing filler.

A rubber reinforcing filler and a method for preparing rubber reinforcing filler by activation and modification of coal gangue are provided. The method includes the following steps: providing coal gangue raw material; crushing coal gangue raw materials; the crushed coal gangue raw materials are ultrafine grinding to obtain coal gangue particles; coal gangue particles were obtained by air flow classification. Activation of coal gangue particles; the activated gangue particles were surface modified and ground to obtain the modified gangue particles. The invention relates to the field of comprehensive utilization of coal gangue and the technical field of rubber filler. The method is simple and effective, which can complete the blending modification of coupling agent and activated coal gangue particles for surface modification at low cost, so as to avoid the waste of materials in the traditional modification process and realize the preparation of high quality rubber reinforcing filler.

A tire component formed from a rubber composition comprises a majority weight percent of renewable materials. The rubber composition comprises, based on 100 parts per weight (phr) of elastomer: a blend of at least two rubber elastomers selected from a group consisting of: from about 15 phr to about 50 phr polybutadiene; up to about 20 phr of styrenebutadiene copolymer; up to about 90 phr of natural rubber; a bio-derived resin material; a vegetable triglyceride oil; and a bio-derived filler comprising silica and carbon black filler. The carbon black filler is at least partially derived from a bio-based feedstock prior to its addition to the rubber composition. The resin and the silica are also derived from renewable materials. In some embodiments, the contemplated polybutadiene may be from mass balanced feedstocks.

A tire component formed from a rubber composition comprises a majority weight percent of renewable materials. The rubber composition comprises, based on 100 parts per weight (phr) of elastomer: a blend of at least two rubber elastomers selected from a group consisting of: from about 15 phr to about 50 phr polybutadiene; up to about 20 phr of styrenebutadiene copolymer; up to about 90 phr of natural rubber; a bio-derived resin material; a vegetable triglyceride oil; and a bio-derived filler comprising silica and carbon black filler. The carbon black filler is at least partially derived from a bio-based feedstock prior to its addition to the rubber composition. The resin and the silica are also derived from renewable materials. In some embodiments, the contemplated polybutadiene may be from mass balanced feedstocks.

An object of the invention is to provide a pneumatic tire having excellent durability. In the pneumatic tire, a content of sulfur (US) in a rubber composition (U) used in an upper bead filler, a content of sulfur (LS) in a rubber composition (L) used in a lower bead filler, and a content of sulfur (PS) in a rubber composition (P) used in a pad satisfy the following Expression (1) and Expression (2).

4.0<LS-US<7.0  Expression (1)

4.0<LS-PS<7.0  Expression (2)

An object of the invention is to provide a pneumatic tire having excellent durability. In the pneumatic tire, a content of sulfur (US) in a rubber composition (U) used in an upper bead filler, a content of sulfur (LS) in a rubber composition (L) used in a lower bead filler, and a content of sulfur (PS) in a rubber composition (P) used in a pad satisfy the following Expression (1) and Expression (2).

4.0<LS-US<7.0  Expression (1)

4.0<LS-PS<7.0  Expression (2)

A method for producing polyisoprene, the method comprising the steps of preparing a preformed lanthanide-based catalyst in the presence of 1,3-butadiene and forming a polymerization mixture by introducing the preformed catalyst to isoprene, where the polymerization mixture includes less than 20% by weight of organic solvent based upon the total weight of the polymerization mixture.

A method for producing polyisoprene, the method comprising the steps of preparing a preformed lanthanide-based catalyst in the presence of 1,3-butadiene and forming a polymerization mixture by introducing the preformed catalyst to isoprene, where the polymerization mixture includes less than 20% by weight of organic solvent based upon the total weight of the polymerization mixture.