Abstract: A method for preparing a functionalized polymer comprising the steps of preparing a pseudo-living polymer by polymerizing conjugated diene monomer with a lanthanide-based catalyst, and reacting the pseudo-living polymer with at least one functionalizing agent defined by the formula (I) where A is a substituent that will undergo an addition reaction with a pseudo-living polymer, R1 is a divalent organic group, R2 is a monovalent organic group, and each R4, which may be the same or different, is a monovalent organic group or a substituent defined by —OR5 where R5 is a monovalent organic group, with the proviso that A, R1, R2, R4, and R5 are substituents that will not protonate a pseudo-living polymer. Also, the functionalized polymer and a vulcanizable composition containing the polymer.

Abstract: A method for preparing a functionalized polymer comprising the steps of preparing a pseudo-living polymer by polymerizing conjugated diene monomer with a lanthanide-based catalyst, and reacting the pseudo-living polymer with at least one functionalizing agent defined by the formula (I) where A is a substituent that will undergo an addition reaction with a pseudo-living polymer, R1 is a divalent organic group, R2 is a monovalent organic group, and each R4, which may be the same or different, is a monovalent organic group or a substituent defined by —OR5 where R5 is a monovalent organic group, with the proviso that A, R1, R2, R4, and R5 are substituents that will not protonate a pseudo-living polymer. Also, the functionalized polymer and a vulcanizable composition containing the polymer.

Abstract: A functionalized polymer prepared by a process comprising the steps of preparing a pseudo-living polymer by polymerizing conjugated monomer with a lanthanide-based catalyst, and reacting the pseudo-living polymer with a functionalizing agent defined by the formula (I) A-R1-Z??(I) where R1 is a divalent bond or divalent organic group comprising from 0 to about 20 carbon atoms, A is a substituent that will undergo an addition reaction with a pseudo-living polymer, and Z is a substituent that will react or interact with silica or carbon black reinforcing fillers, with the proviso that A, R1, and Z are substituents that will not protonate a pseudo-living polymer.

Abstract: Disclosed are a method for producing a modified conjugated diene polymer improved in quality stability, more enhanced in low heat buildup and reinforcing ability when used in a rubber composition, excellent in wear resistance, mechanical characteristics and processability, and improved in cold flow; and a rubber composition using the same. The method includes a step of modifying an active end of an active end-containing conjugated diene polymer having a cis-1,4-bond content of 75% or more with an alkoxysilane compound containing at least one functional group selected from the group consisting of (a) an epoxy group, (b) an isocyanate group and (c) a carboxyl group, and a step of adding a condensation accelerator to conduct condensation reaction of the alkoxysilane compound (residue) in an aqueous solution having a pH of 9 to 14 and a temperature of 85 to 180° C.

Abstract: A novel modified conjugated diene polymer is obtained by polymerizing a conjugated diene compound with a specified catalyst consisting of components (a)-(c) and then reacting with at least one specified compound selected from the group consisting of components (d)-(l), and has a content of cis-1,4-bond of not less than 85% and a ratio of weight average molecular weight to number average molecular weight of not more than 4. And also, a rubber composition comprises the modified conjugated diene polymer a rubber ingredient.

Abstract: Novel conjugated diene polymers having good wear resistance, mechanical properties, storage stability, processability and a reduced cold flow are produced by polymerizing a conjugated diene compound with a catalyst of rare earth element compound and reacting the resulting polymer just after the polymerization with at least one compound selected from the group consisting of a halogenated organometallic compound, a halogenated metal compound, an organometallic compound, a heterocumulene compound, a hetero three-membered-ring containing compound, a halogenated isocyano compound, a carboxylic acid, an acid halide, an ester compound, a carbonic ester compound, an acid anhydride and a metal salt of a carboxylic acid as a modifying agent.

Abstract: A conjugated diene polymer is produced by continuously polymerizing a conjugated diene monomer with a catalyst consisting essentially of specified components (a) to (c) and reacting with at least one of specified components (d) and (e) and has a content of cis-1,4-bond of not less than 85%, a content of 1,2-vinyl bond of not more than 2.0% and a ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) of not more than 5, and contains at least one functional group selected from epoxy group and hydroxyl group in its molecule. And also, a rubber composition comprises 10-200 parts by weight of silica based on 100 parts by weight of rubber ingredient consisting of 10-100% by weight of the above conjugated diene polymer and 90-0% by weight of the other diene polymer or natural rubber.

Abstract: Disclosed is a rubber composition containing (a) 50 parts to 100 parts by weight of polybutadiene rubber having a 1,4-cis bond content of 80 mol % to 100 mol % and a 1,2-vinyl bond content of 0 mol % to 2 mol %, which is modified with an alkoxysilyl group-containing compound, (b) 0 part to 50 parts by weight of diene rubber other than the above-mentioned component (a) (wherein the total amount of component (a) and component (b) is 100 parts by weight), (c) 10 parts to 50 parts by weight of a crosslinkable monomer, (d) 5 parts to 80 parts by weight of an inorganic filler and (e) 0.1 part to 10 parts by weight of an organic peroxide, and a solid golf ball improved in flight, durability and the feeling of ball hitting can be produced from the rubber composition.

Abstract: A conjugated diene polymer is produced by continuously polymerizing a conjugated diene monomer with a catalyst consisting essentially of specified components (a) to (c) and reacting with at least one of specified components (d) and (e) and has a content of cis-1,4-bond of not less than 85%, a content of 1,2-vinyl bond of not more than 2.0% and a ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) of not more than 5, and contains at least one functional group selected from epoxy group and hydroxyl group in its molecule. And also, a rubber composition comprises 10-200 parts by weight of silica based on 100 parts by weight of rubber ingredient consisting of 10-100% by weight of the above conjugated diene polymer and 90-0% by weight of the other diene polymer or natural rubber.

Abstract: Disclosed is a rubber composition containing (a) 50 parts to 100 parts by weight of polybutadiene rubber having a 1,4-cis bond content of 80 mol % to 100 mol % and a 1,2-vinyl bond content of 0 mol % to 2 mol %, which is modified with an alkoxysilyl group-containing compound, (b) 0 part to 50 parts by weight of diene rubber other than the above-mentioned component (a) (wherein the total amount of component (a) and component (b) is 100 parts by weight), (c) 10 parts to 50 parts by weight of a crosslinkable monomer, (d) 5 parts to 80 parts by weight of an inorganic filler and (e) 0.1 part to 10 parts by weight of an organic peroxide, and a solid golf ball improved in flight, durability and the feeling of ball hitting can be produced from the rubber composition.

Abstract: A conjugated diene polymer is obtained by using a specified catalyst system consisting of components (a)-(d) and indicating a high polymerization activity to a conjugated diene compound. Further, a modified conjugated diene polymer is obtained by reacting with at least one specified compound selected from the group consisting of components (e)-(j).

Abstract: A rubber composition for solid golf balls comprising: (a) 50 to 100 parts by weight of a polybutadiene rubber with a 1,4-cis bond content of 80% or more, a 1,2-vinyl bond content of 2.0% or less, and a ratio (Mw/Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of 3.5 or less, (b) 0 to 50 parts by weight of a diene-type rubber other than the component(a), provided that the total amount of the component (a) and component (b) is 100 parts by weight, (c) 10 to 50 parts by weight of a cross-linking monomer, (d) 20 to 80 part by weight of inorganic filler, and (e) an effective amount of an organic peroxide. The solid golf balls prepared from the rubber composition provide a good shot feeling, run a long distance, and exhibit superior durability.

Abstract: A method for preparing a conjugated diene polymer characterized by polymerizing a conjugated diene in vapor phase in the presence of an inorganic filler used as a rubber reinforcement agent and a catalyst which comprises (a) a compound containing a rare earth element of an atomic number of from 57 to 71 in the Periodic Table or a compound obtained by the reaction of this rare earth element-containing compound and a Lewis base, (b) an organic aluminum compound of the formula AlR.sup.1 R.sup.2 R.sup.3 or an almoxane, and (c) a halogen-containing compound. The vapor phase polymerization ensures easy control of the molecular weight of the polymer better dispersion of a rubber enforcement agent, and provides a rubber composition with improved rupture characteristics and abrasion resistance.