Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Patent
1996-01-29
1998-12-01
Lipman, Bernard
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
5253328, 5253329, 5253331, 5253332, 525352, 525379, C08F 832
Patent
active
058440500
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a modified conjugated diene polymer obtained by highly modifying by a specific compound a conjugated diene polymer prepared by polymerization using a lanthanoid rare earth element-containing catalyst, a process for producing the modified conjugated diene polymer, and a rubber composition comprising the modified conjugated diene polymer.
BACKGROUND ART
High-cis polybutadiene produced by polymerization using a lanthanoid rare earth element-containing catalyst is generally a straight-chain polymer having only few branched chains, and has good abrasion resistance and fatigue resistance as compared with conventional high-cis polybutadiene produced by polymerization using a catalyst containing Co, Ni or Ti as the principal ingredient. However, in recent years, there is an increasing demand for vehicle tires having a higher abrasion resistance and a high rebound resilience for reducing the fuel consumption.
Catalysts containing a lanthanoid rare earth element-containing compound have been proposed which include, for example, a catalyst composition comprising (i) a reaction product of a carboxylic acid salt of a lanthanoid rare earth element such as neodymium with a Lewis base such as acetyl-acetone, (ii) an organoaluminum halide compound compound such as diethylaluminum chloride and (iii) an organoaluminum compound such as triethylaluminum (Japanese Examined Patent Publication H1-16244), a catalyst composition comprising the above three ingredients (i), (ii) and (iii) and further an organoaluminum hydride compound such as diisobutylaluminum hydride (Japanese Examined Patent Publication H1-55287). However, rubbers having satisfactory processability, tensile properties and rebound resilience cannot be obtained with these catalysts containing a lanthanoid rare earth element compound. Of these properties, an improvement of rebound resilience and tensile properties is eagerly desired.
It is known that an active group-terminated living copolymer prepared by polymerization using an alkali metal-containing catalyst such as an organolithium catalyst is coupled with a polyfunctional compound such as tin tetrachloride or silicon tetrachloride to improve the cold flow property and rebound resilience of the copolymer, and that the terminal group of the copolymer is modified with a specific polar compound to improve the rebound resilience and other cured properties. As examples of the polar compound used for the modification, there can be mentioned aromatic ketone compounds such as 4,4'-bis(dliethylamino) benzophenone (hereinafter abbreviated to "EAB") (Japanese Unexamined Patent Publication S58-162604), and linear and cyclic compounds having a--C(.dbd.M)--N<bond (wherein M is an oxygen atom or a sulfur atom) such as N,N,N',N'-tetramethyl-thiourea and N-methyl-.epsilon.-caprolactam (Japanese Unexamined Patent Publication S60-137913).
It also is known that a living polymer is prepared by polymerization using a catalyst comprising a lanthanoid rare earth element-containing compound, and the living polymer is modified at the terminal or is subjected to a coupling modification. However, where the coupling modification is effected by a polyfunctional compound, the modified polymer is not satisfactory in abrasion resistance. Only a few proposals have been made for the terminal modification of the living polymer. As examples of a modifier used for the terminal coupling modification, there can be mentioned tetrahalomethane (Japanese Unexamined Patent Publication S60-40109), an alkyltin halide or alkylgermanium halide compound (Japanese Unexamined Patent Publication S63-178102), carboxylic acid compounds (Japanese Unexamined Patent Publication H5-59103), and ester compounds (Japanese Unexamined Patent Publication H5-59406). As examples of the terminal modifier used for the terminal modification, there are known only a few terminal modifiers, which include active halide compounds such as 2,4,6-trichloro-1,3,5-triazine and benzoyl chloride (Japanese Unexamined Patent Publication S63-305101
REFERENCES:
patent: 4461883 (1984-07-01), Takeuchi et al.
patent: 4647625 (1987-03-01), Aonuma et al.
patent: 5064910 (1991-11-01), Hattori et al.
Derwent WPI, Week 8344; JP-A-58-162604, Abstract (Sep. 27, 1983).
Derwent WPI, Week 8515; JP-A-60-40109, Abstract (Mar. 2, 1985).
Derwent WPI, Week 9315; JP-A-50-59103, Abstract (Mar. 9, 1993).
Derwent WPI, Week 9314; JP-A-5-51406, Abstract (Mar. 2, 1993).
Fukahori Takahiko
Inamura Kiyoshi
Lipman Bernard
Nippon Zeon Co. Ltd.
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