Abstract: An isoprene polymerization catalyst composition includes: Component (a): a rare earth element compound having a rare earth element-oxygen bond or a rare earth element-sulfur bond; Component (b): an ionic compound; and Component (c): at least one compound selected from the group consisting of a compound of formula (X): YR1aR2bR3c and a compound having a repeating unit of formula (Y): (—Y(R1)O—) (where Y is a metal selected from groups 1, 2, 12 and 13 in a periodic table, R1 and R2 are C1-10 hydrocarbon groups or hydrogen atoms and R3is a C1-10 hydrocarbon group).

Abstract: Provided is a rubber composition including a rubber component. The rubber component contains at least a polymer that is a synthesized polyisoprene or an isoprene copolymer and that has 20% or less gel fraction.

Abstract: The polymerization catalyst composition includes: Component (A): a rare earth element compound of formula (i): M-(NQ1)(NQ2)(NQ3) (where M is at least one selected from lanthanoid, scandium, and yttrium, and NQ1, NQ2 and NQ3 are amide groups and each have a M-N bond; Component (B): a hydrocarbyl aluminoxane compound having a C1-20 hydrocarbon group; and Component (C): a compound of formula (X): YR1aR2bR3c (where Y is a metal selected from groups 1, 2, 12 and 13 in a periodic table, R1 and R2 are C1-10 hydrocarbon groups or hydrogen atoms and R3 is a C1-10 hydrocarbon group).

Abstract: A copolymer having properties (durability (fracture resistance, abrasion resistance, and crack-growth resistance)) similar to those of natural rubber and a method of producing the copolymer are provided. An isoprene copolymer has a styrene block or a butadiene block at a terminal thereof, wherein styrene monomers account for less than 5 mol % of all monomers forming the isoprene copolymer having the styrene block; butadiene monomers account for 10 mol % or less of all monomers forming the isoprene copolymer having the butadiene block; and cis-1,4 bond content of a portion derived from isoprene accounts for at least 95% in total.

Abstract: This disclosure is to provide a method for preparing a terminal-modified conjugated diene polymer which achieves an extremely high compounding amount of cis-1,4 without complicated preparing conditions, a terminal-modified conjugated diene polymer obtained via the method, a rubber composition containing the terminal-modified conjugated diene polymer, and a tire using the rubber composition.

Abstract: A method for manufacturing a conjugated diene polymer that can increase the robustness of a polymerization reaction system is provided. Also, a conjugated diene polymer, with a high cis-1,4-bond content, that is manufactured by this method for manufacturing is provided. A method for manufacturing a conjugated diene polymer includes polymerizing a conjugated diene monomer using a polymerization catalyst composition including a rare earth element compound and a compound having a cyclopentadiene skeleton, and a conjugated diene polymer manufactured with this method for manufacturing has a cis-1,4-bond content of 95% or greater.

Abstract: An object of the present invention is to provide a polymer composition having properties resembling those of natural rubber, e.g. good durability (fracture resistance, wear resistance, and crack growth resistance), and a method for manufacturing the polymer composition. Specifically, the present invention provides a method for manufacturing a polymer composition including a mixture of polyisoprene and polystyrene/polybutadiene, comprising: polymerizing styrene monomer or butadiene monomer in the presence of a catalyst to synthesize polystyrene or polybutadiene; adding isoprene monomer to the polystyrene or polybutadiene thus synthesized, to synthesize polyisoprene and thus generate said mixture, wherein content of the styrene monomer or the butadiene monomer is set to be 10 mol % or less with respect to the total quantity of the styrene monomer/the butadiene monomer and the isoprene monomer.

Abstract: The present invention provides a random copolymer that is used for manufacturing a rubber having high fracture strength and excellent low loss properties (low heat generation properties) and that includes randomly arranged monomer units of a conjugated diene compound and of a non-conjugated olefin, a rubber composition containing the random copolymer, a cross-linked rubber composition obtained by crosslinking the rubber composition, and a tire manufactured by using the rubber composition or the cross-linked rubber composition. A copolymer of a conjugated diene compound and a non-conjugated olefin includes a random copolymer having randomly arranged monomer units of the conjugated diene compound and of the non-conjugated olefin, which random copolymer contains, by at least 5 mol %, alternate bonding units of the conjugated diene compound and the non-conjugated olefin in a unit derived from the non-conjugated olefin.

Abstract: The method for manufacturing a polymer of the present invention is a method for manufacturing a polymer where a hydroxy group is added to a terminal of either one of a homopolymer of a non-conjugated olefin, a homopolymer of a conjugated diene compound, and a copolymer of a conjugated diene compound and a non-conjugated olefin, the method comprising: a first reaction step of reacting a hydrocarbon containing at least either one of the non-conjugated olefin and the conjugated diene compound with an organic aluminum compound, using a rare earth element compound-containing catalyst; a second reaction step of reacting a first reactant obtained from the first reaction step with oxygen; and a third reaction step of reacting a second reactant obtained from the second reaction step with at least either one of water and alcohol.

Abstract: Provided is a copolymer of a conjugated diene compound and a non-conjugated olefin, the copolymer being a tapered copolymer including: at least one of a block sequence including monomer units of the conjugated diene compound and a block sequence including monomer units of the non-conjugated olefin; and a random sequence including randomly arranged monomer units of the conjugated diene compound and monomer units of the non-conjugated olefin.

Abstract: Provided is a method for producing a multicomponent copolymer comprising copolymerizing a conjugated diene compound, a non-conjugated olefin compound, and an aromatic vinyl compound to produce a multicomponent copolymer having a main chain consisting of an acyclic structure.

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: Provided are: a polymer capable of providing a crosslinked rubber composition with improved durability (i.e., breaking resistance, abrasion resistance, and crack growth resistance) and a method for producing the same, a rubber composition containing the polymer, a crosslinked rubber composition obtained by crosslinking the rubber composition, and a tire having the crosslinked rubber composition. The polymer is either a synthesized polyisoprene or an isoprene copolymer, and contains a residual catalyst in an amount of 300 ppm or less.

Abstract: A polymerization catalyst composition that, without accompanying excessive gelation, allows efficient synthesis of high molecular weight polyisoprene under industrial conditions is provided. The polymerization catalyst composition contains: a rare earth element compound (component (A)) represented by the following general formula (i): M-(NQ1)(NQ2)(NQ3)??(i); at least one (component (B)) selected from an ionic compound and a halogen compound; and a compound (component (C)) represented by the following general formula (X): YR1aR2bR3c??(X).

Abstract: This invention relates to a method for producing a copolymer of a conjugated diene compound and an unconjugated olefin other than the conjugated diene compound having a high cis-1,4 bond content of a conjugated diene compound portion, and more particularly to a method for producing a copolymer characterized by comprising a step of polymerizing a conjugated diene compound and an unconjugated olefin other than the conjugated diene compound in the presence of a polymerization catalyst composition including at least one complex selected from a metallocene complex represented by the following general formula (I): (wherein M is a lanthanoid element, scandium or yttrium, and CpR is independently a non-substituted or substituted indenyl, and Ra-Rf are independently an alkyl group having a carbon number of 1-3 or a hydrogen atom, and L is a neutral Lewis base, and w is an integer of 0-3) and so on.

Abstract: A method for producing a polymer containing silica that does not involve long kneading time, and a polymer composition having an intended low heat generation property. A polymerization catalyst composition is produced by mixing and aging a second element and a third element, and then adding a first element to the mixture to react the first element with the mixture. The first element contains a compound that contains a rare earth metal element, the second element contains a compound represented by the following formula (X), and the third element contains silica. YR1aR2bR3c (X) (In the formula, Y is a metal; R1 and R2 are hydrogen atoms or hydrocarbon groups; and R3 is a hydrocarbon group, and R1, R2, and R3 are the same as or different from each other, a, b, and c are 0 or 1.).

Abstract: Disclosed is a method of manufacturing a copolymer of a conjugated diene compound and an olefin other than the conjugated diene compound, where a conjugated diene compound and an olefin other than the conjugated diene compound is copolymerized in the presence of a polymerization catalyst composition containing components: (A) a rare earth element compound or a reactant of the rare earth element compound and a Lewis base; and (B) at least one selected from a group consisting of an ionic compound (B-1) composed of a non-coordinating anion and a cation, an aluminoxane (B-2), and at least one kind of halogen compound (B-3) selected from among a Lewis acid, a complex compound of a metal halide and a Lewis base, and an organic compound containing active halogen (when containing at least one of (B-1) and (B-3), the polymerization catalyst composition further contains component (C): an organometallic compound).

Abstract: The polymerization catalyst composition includes: Component (A): a rare earth element compound of formula (i): M-(NQ1)(NQ2)(NQ3) (where M is at least one selected from lanthanoid, scandium, and yttrium, and NQ1, NQ2 and NQ3 are amide groups and each have a M-N bond; Component (B): a hydrocarbyl aluminoxane compound having a C1-20 hydrocarbon group; and Component (C): a compound of formula (X): YR1aR2bR3c (where Y is a metal selected from groups 1, 2, 12 and 13 in a periodic table, R1 and R2 are C1-10 hydrocarbon groups or hydrogen atoms and R3 is a C1-10 hydrocarbon group).

Abstract: An isoprene polymerization catalyst composition includes: Component (a): a rare earth element compound having a rare earth element-oxygen bond or a rare earth element-sulfur bond; Component (b): an ionic compound; and Component (c): at least one compound selected from the group consisting of a compound of formula (X): YR1aR2bR3c and a compound having a repeating unit of formula (Y): (—Y(R1)O—) (where Y is a metal selected from groups 1, 2, 12 and 13 in a periodic table, R1 and R2 are C1-10 hydrocarbon groups or hydrogen atoms and R3 is a C1-10 hydrocarbon group).

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.