# US 6,294,624 B1 · Modified diene elastomer and its preparation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,294,624 B1 - Document ID: US6294624B1 - Status: Granted - Kind: B1 - Application number: 09/489,781 - Filed: 2000-01-24 - Granted: 2001-09-25 - Earliest claimed: 1999-01-22 - Assignees: Ube Industries, Ltd.; Sumitomo Rubber Industries, Ltd. - Inventors: Tokuji Inoue; Tetsuji Nakajima; Kiyoshige Muraoka; Noriko Yagi - Web page: https://patentgrep.com/patent/US6294624B1 ## CPC - C08L 19/006: {Rubber characterised by functional groups, e.g. telechelic diene polymers} - B60C 1/0016: {Compositions of the tread} - C08C 19/25: Incorporating silicon atoms into the molecule - C08F 36/04: conjugated - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) - B60C: VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES - C08C: TREATMENT OR CHEMICAL MODIFICATION OF RUBBERS - C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS ## Abstract A modified diene elastomer prepared by a process comprising the steps of polymerizing a diolefin compound containing a conjugated double bond in a liquid phase in the presence of a cobalt compound, an organic aluminum compound containing a halogen atom, and water, to give a solution containing a diene elastomer, and reacting the diene elastomer with an elastomer-modifying compound is favorably employed for the manufacture of tire tread, particularly when it is employed in combination with silica as a filler. ## Claims ### Claim 1 A process for preparing a modified diene elastomer which comprises the steps of: polymerizing a diolefin compound containing a conjugated double bond in a liquid phase in the presence of a cobalt compound, an organic aluminum compound containing a halogen atom, and water, to give a solution containing a diene elastomer; and reacting the diene elastomer with an elastomer-modifying compound. ### Claim 2 (depends on 1) The process of claim 1, wherein the diolefin compound containing a conjugated double bond is 1,3-butadiene or isoprene. ### Claim 3 (depends on 1) The process of claim 1, wherein the cobalt compound is a cobalt salt of a carboxylic acid having 1 to 18 carbon atoms. ### Claim 4 (depends on 1) The process of claim 1, wherein the organic aluminum compound containing a halogen atom is a dialkylaluminum halide, an alkylaluminum dihalide, or an alkylaluminum sesquihalide, each of which contains 2 to 10 carbon atoms in total. ### Claim 5 (depends on 1) The process of claim 1, wherein the elastomer-modifying compound is an organic silicon compound having an amino group and an alkoxy group, an organo-alkoxysilane, or an organo-aroxysilane. ### Claim 6 (depends on 5) The process of claim 5, wherein the elastomer-modifying compound is an organic silicon compound having an amino group and an alkoxy group which is selected from the group consisting of 3-aminopropyltrimethoxysilane, 3-(2-aminoethylaminopropyl)dimethoxymethylsilane, and 3-(2-aminoethylpropyl) trimethoxysilane. ### Claim 7 (depends on 5) The process of claim 5, wherein the elastomer-modifying compound is an organo-alkoxysilane or an organo-aroxysilane which has the formula (I): R1k(R2O)mSiHn (I) in which each of R1 and R2 independently represents a hydrocarbyl group having 1 to 20 carbon atoms, k is an integer of 0 to 3, m is an integer of 1 to 4, and n is an integer of 0 to 3, provided that k+m+n is 4. ### Claim 8 (depends on 7) The process of claim 7, wherein R1 of the formula (I) represents an alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 13 carbon atoms, and R2 represents an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 13 carbon atoms. ### Claim 9 (depends on 1) The process of claim 1, wherein the cobalt compound, the organic aluminum compound containing a halogen atom, and water are present, respectively, in amounts of 1×10−7 to 1×10−3 mol., 1×10−5 to 1×10−1 mol., and 1×10−5 to 1×10−1 mol., each being per one mole of the diolefin compound. ### Claim 10 (depends on 1) The process of claim 1, wherein the polymerization of the diolefin compound is performed at a temperature in the range of 30 to 100° C. ### Claim 11 (depends on 1) The process of claim 1, wherein the polymerization of the diolefin compound is performed in the presence of an organic solvent which dissolves the diolefin compound, the diene elastomer, and the modified diene elastomer. ### Claim 12 (depends on 1) The process of claim 1, wherein the reaction of the diene elastomer with the elastomer-modifying compound is performed after addition of the elastomer-modifying compound into the solution containing a diene elastomer. ### Claim 13 (depends on 12) The process of claim 12, wherein the reaction of the diene elastomer with the elastomer-modifying compound is performed at a temperature of room temperature to 70° C. ### Claim 14 A modified diene elastomer containing at least 80% of cis-1,4-structure units in its recurring units, a Mooney viscosity of 20 to 80 in terms of ML1+4 at 100° C., and a weight average molecular weight of 200,000 to 1,000,000 measured by a gel permeation method, which is prepared by a process comprising the steps of polymerizing a diolefin compound containing a conjugated double bond in a liquid phase in the presence of a cobalt compound, an organic aluminum compound containing a halogen atom, and water, to give a solution containing a diene elastomer, and reacting the diene elastomer with an elastomer-modifying compound. ### Claim 15 (depends on 14) The modified diene elastomer of claim 14, wherein the diolefin compound containing a conjugated double bond is 1,3-butadiene and the diene elastomer is polybutadiene. ### Claim 16 (depends on 14) The modified diene elastomer of claim 14, wherein the elastomer-modifying compound is an organic silicon compound having an amino group and an alkoxy group, an organo-alkoxysilane, or an organo-aroxysilane. ### Claim 17 An elastomer composition comprising an elastomer component which is composed of 10 to 80 weight % of a modified diene elastomer containing at least 80% of cis-1,4-structure units in its recurring units, a Mooney viscosity of 20 to 80 in terms of ML1+4 at 100° C., and a weight average molecular weight of 200,000 to 1,000,000 measured by a gel permeation method, which is prepared by a process comprising the steps of polymerizing a diolefin compound containing a conjugated double bond in a liquid phase in the presence of a cobalt compound, an organic aluminum compound containing a halogen atom, and water, to give a solution containing a diene elastomer, and reacting the diene elastomer with an elastomer-modifying compound, and 20 to 90 weight % of one or more other elastomer compounds, and silica in an amount of 5 to 100 weight parts per 100 weight parts of the elastomer component. ### Claim 18 (depends on 17) The elastomer composition of claim 17, wherein a silane coupling agent is further contained in an amount of at most 15 weight parts per 100 weight parts of the silica. ### Claim 19 (depends on 18) The elastomer composition of claim 18, wherein a silane coupling agent is contained in an amount of at most 10 weight parts per 100 weight parts of the silica. ### Claim 20 A tire tread employing an elastomer composition comprising an elastomer component which is composed of 10 to 80 weight % of a modified diene elastomer containing at least 80% of cis-1,4-structure units in its recurring units, a Mooney viscosity of 20 to 80 in terms of ML1+4 at 100° C., and a weight average molecular weight of 200,000 to 1,000,000 measured by a gel permeation method, which is prepared by a process comprising the steps of polymerizing a diolefin compound containing a conjugated double bond in a liquid phase in the presence of a cobalt compound, an organic aluminum compound containing a halogen atom, and water, to give a solution containing a diene elastomer, and reacting the diene elastomer with an elastomer-modifying compound, and 20 to 90 weight % of one or more other elastomer compounds, and silica in an amount of 5 to 100 weight parts per 100 weight parts of the elastomer component.