Nippon Zeon Company, Ltd.

The Yokohama Rubber Co., Ltd.

Tokai Rubber Industries, Ltd.

Societe Chimique Des Charbonnages S.a.

Akio Ueda

Shuichi Akita

Hiroyuki Watanabe

Keiji Komuro

Takeshi Chida

Tetsuo Ohyama

Haruki Kawada

Mitsuyoshi Aonuma

Hiroshi Hirakawa

Nagatoshi Sugi

Fumitoshi Suzuki

Tetsu Ohishi

Asahiro Ahagon

Toshio Kase

Akihiro Shibahara

Kohkichi Noguchi

Claude Stein

Satoru Isomura

Toshio Namizuka

Tetsuo Waku

Souichi Suzuki

Tetsuo Oyama

Hitoshi Nagai

A rubber composition which gives a rubber vibration insulator having excellent low-temperature properties comprises as a main rubber component a blend composed of (a) 10 to 90 parts by weight of a tapered styrene/butadiene copolymer rubber which has an average bound styrene content of 10 to 40% by weight and a 1,2-bond content in the butadiene portion of at least 50% by weight and in which the bound styrene content increases or decreases in one direction along the copolymer molecular chain and (b) 90 to 10 parts by weight of natural rubber and/or synthetic polyisoprene rubber.

Rubber composition

A vibration insulating rubber having an improved balance between its loss tangent and dynamic-to-static modulus ratio is prepared by molding and curing a rubber compound comprising as a rubber component a modified rubbery polymer obtained by reacting (1) a rubbery polymer having at least one metal selected from alkali metals and alkaline earth metals bonded to its molecular chain with (2) at least one compound selected from organic compounds having a bond of the formula ##STR1## wherein X represents an oxygen or sulfur atom, in the molecule, benzophenones having at least one of unsubstituted and substituted amino groups, and thiobenzophenones having at least one of unsubstituted or substituted amino groups.

Vibration insulating rubber

Articles having shape recovering properties and methods of using them are disclosed. An article is formed from a composition containing a norbornene polymer by forming said polymer into an article having a first shape, then deforming the article in the solid state to a second shape and cooling the article to a first temperature at or below the glass transition temperature of the polymer to retain said second shape, and finally heating said article to a temperature above the first temperature to recover the first shape.

Articles having shape recovering properties and a method for using it

A process for modifying a polymer of a conjugated diene, which comprises reacting a polymer of a conjugated diene containing at least one metal selected from alkali metals and alkaline earth metals with a compound having a linkage of the following formula ##STR1## wherein X represents an oxygen or sulfur atom, in the molecule.

Process for modifying conjugated diene polymers

A rubber composition for tire treads, comprising [I] 10 to 70% by weight of a polybutadiene rubber having bonded to a carbon atom of the rubber molecular chain at least 0.1 mole, per mole of the rubber molecular chain, of an atomic grouping represented by the following formula ##STR1## wherein X represents O or S, R.sub.1 and R.sub.2 are identical or different and each represents an amino group or an alkyl-substituted amino group, R.sub.3 and R.sub.4 are identical or different and each represents a substituent other than the above-mentioned, m, p and q each represent O or an integer of at least 1, n represents an integer of at least 1, m+p=0-5, and n+q=1-5, and [II] 90 to 30% by weight of at least one rubber selected from the group consisting of styrene-butadiene copolymer rubber having a bound stryene content of not more than 50% by weight and polyisoprene rubber.

Rubber composition for tire treads

A rubber composition for tire treads, comprising [I] 10 to 90% by weight of a styrene-butadiene copolymer rubber containing not more than 40% by weight of bound styrene and having bonded to a carbon atom of the rubber molecular chain at least 0.1 mole, per mole of the rubber molecular chain, of an atomic grouping represented by the following formula ##STR1## wherein: X represents O or S,

A rubber material having an excellent grip on ice comprising a mixture of an ordinary rubber and a powdered polymer, said powdered polymer having a maximum of tan .delta. at a temperature in the range of -5.degree. C. to +35.degree. C. when the tan .delta. is measured by a nonresonance, forced vibration apparatus at a frequency of 110 hertz and a heating rate of 2.degree. C./minute.

Rubber materials having excellent grip on ice

A rubber composition comprising as main components (1) at least one rubber having a glass transition temperature of from -45.degree. C. to 0.degree. C. and selected from the group consisting of an isoprene-butadiene copolymer rubber and polyisoprene rubber and (2) at least one rubber selected from the group consisting of natural rubber and cis-1,4-polyisoprene rubber having a cis-1,4-linkage content of at least 90 mole %, said composition having a value, defined by the following formula, of at least 10,

A process for preparing a tire tread rubber composition having improved rolling resistance and wet skid resistance comprising [I] 100 parts by weight of a rubber material composed of 25 to 75% by weight of substantially amorphous polybutadiene having a 1,2-bond unit content of 65 to 90 mole % and a Mooney viscosity (ML.sub.1+4, 100.degree. C.) of 20 to 100 and 75 to 25% by weight of natural rubber and/or cis-1,4-polyisoprene, and [II] 40 to 70 parts by weight of carbon black, said process comprising (1) mechanically compounding 40 to 60 parts by weight of the rubber material [I] with 40 to 70 parts by weight of carbon black [II], and then (2) adding to the resulting mixture the rubber material [I] in an amount sufficient to adjust the amount of the carbon black [II] to 40 to 70 parts by weight per 100 parts by weight of the rubber material [I] and mechanically compounding them.

Process for preparing rubber composition for tire treads

A rubber composition for the tread of tire having reduced rolling resistance and increased wet skid resistance with the mechanical properties unimpaired, said rubber composition comprising 20 to 80% by weight of (I) essentially amorphous polybutadiene having a 1,2-bond units content of at least 70% and a Mooney viscosity (ML.sub.1+4, 100.degree. C.) of 10 to 100; 10 to 75% by weight of (II) polybutadiene rubber having a 1,2-bond units content of 20% or less and a Mooney viscosity (ML.sub.1+4, 100.degree. C.) of 20 to 130; and 3 to 35% by weight of (III) at least one rubber selected from styrene/butadiene copolymer rubber having a bound styrene content of 15 to 25% by weight, natural rubber, and polyisoprene rubber having a cis-1,4-bond units content of at least 90%.

Rubber composition for tire tread

Rubber composition and process for preparation thereof

A rubber composition for tire treads includes (Ia) an oil-extended rubber having a Mooney viscosity (ML.sub.1+4, 100.degree. C) of 20 to 70 which is prepared by adding 20 to 80 parts of a hydrocarbon oil to 100 parts by weight of a rubber terpolymer which is composed of 2 to 13% by weight of combined styrene, 15 to 70% by weight of combined 1,3-butadiene and 17 to 83% by weight of combined 1,3-pentadiene with the dienes having a total 1,4-bond content of at least 65 mole%, (II) vulcanization additives, and (III) 30 to 110 parts by weight, per 100 parts by weight of the oil-extended rubber (Ia), of a carbon black for rubber having an average particle diameter of not more than 60 m.mu. the rubbery copolymer has a glass transistion temperature of -70.degree. to -20.degree. C., and is produced by emulsion-polymerization at 0.degree. to 30.degree. C.

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Yokohama, Japan

Akio Ueda