Mitsui Petrochemical Industries, Ltd.

Mitsui Chemicals, Inc.

Tetsuo Tojo

Masaaki Kawasaki

Keiji Okada

Katsuo Okamoto

Takashi Hakuta

Yasuhiko Otawa

Toshiyuki Tsutsui

Toshihiro Sagane

Yoshiharu Kikuchi

Hidenari Nakahama

Takashi Nakahara

Akira Matsuda

Toshiyuki Maeda

Mikio Hosoya

Taku Koda

Kyoko Kobayashi

Toshimasa Takata

Kazuhiko Murata

Noboru Sakamaki

Kazuo Iwata

Akira Uchiyama

Syuji Minami

Yuichi Itoh

Tetsuhiro Matsumoto

Kenichi Morizono

Yuji Ishii

Kazuyuki Takimoto

Shuichi Nonaka

Tatsuya Tanizaki

Muneyuki Matsumoto

Masao Kunizane

Akemi Uchimi

Yasuhiro Hosomi

Mitsuhiko Onda

Eckhart Louis

Kenzaburo Fukutani

Totshiyuki Tsutsui

Yuji Miura

Yoshio Maejima

An olefin thermoplastic elastomer composition comprises a crystalline polyolefin resin (A) and an ethylene/&agr;-olefin/nonconjugated polyene copolymer rubber (B), and optionally a softener (C) and/or an inorganic filler (D), in a specific ratio. The copolymer rubber (B) is prepared by the use of a metallocene catalyst and comprises ethylene, an &agr;-olefin of 3 to 20 carbon atoms and a nonconjugated polyene. This composition ca provide molded products of more excellent tensile strength, elongation at break, elastomeric properties (elongation set, permanent compression set, etc.), heat resistance and low-temperature properties than the conventional non-crosslinked olefin thermoplastic elastomers, even if the composition is in the non-crosslinked form. The composition in the partially or completely crosslinked form can provided molded products of more excellent low-temperature properties, tensile strength, elongation at break and elastomeric properties than the conventional vulcanized rubbers.

Olefin thermoplastic elastomer composition comprising crystalline polyolefin resin and ethylene/&agr;-olefin/nonconjugated polyene copolymer rubber

Rubber modified with ethylene/&agr;-olefin(/diene) rubber(s)

Rubber composition for a conveyor belt

Rubber modifier of ethylene/&agr;-olefin (/diene) copolymer rubber(s)

The heat-resistant rubber composition of the invention is a vulcanizable composition comprising 100 parts by weight of a specific ethylene-&agr;-olefin-nonconjugated polyene copolymer rubber (A) composed of ethylene, an &agr;-olefin or 3 to 20 carbon atoms and a nonconjugated polyene which is a vinyl end group-containing norbornene compound, 0.2 to 5 parts by weight of an amine type anti-aging agent (C) and/or a hindered phenol type anti-aging agent (D), 1 to 10 parts by weight of a sulfur type anti-aging agent (E) and an organic peroxide (B). This heat-resistant rubber composition can provide a vulcanized rubber molded product showing not only excellent mechanical properties and electrical properties and but also prominently high thermal aging resistance.

Heat-resistant rubber composition

A rubber composition useful as a tire side wall or tire tread is formed from an unsaturated olefin copolymer (A) or (A&prime;) and diene rubber (B). Copolymers (A) and (A&prime;) are each obtained from (i) ethylene, (ii) aromatic vinyl compound, (iii) non-conjugated polyene, and, optionally (iv) alpha-olefin having at least 3 carbon atoms. When used in forming a tire side wall, copolymer (A) has a molar ratio of (i)/(iv) from 100/0 to 40/60; molar ratio of &lsqb;((i)&plus;(iv))/(ii)&rsqb; from 98/2 to 60/40; an intrinsic viscosity, measured in decalin, at 135&deg; C., from 1.0 to 6.0 dl/g; and iodine value from 10 to 50. For use in tire tread, copolymer (A&prime;), has a molar ratio (i)/(iv) from 100/0 to 40/60; molar ratio &lsqb;((i)&plus;(iv)):(ii)&rsqb; from 99/1 to 85/15. The weight ratio (A&prime;)/(B) is from 1/99 to 50/50. The compositions for tire side wall are characterized by excellent strength properties and bending fatigue resistance and low fuel consumption. The compositions for tire tread are characterized by superior strength properties, abrasion resistance and braking performance on wet road (wet ski resistance) and small rolling resistance.

Rubber compositions for tires

Ethylenic random copolymer, process for preparing the same, and rubber

A curable rubber composition comprises of a silicone rubber (A) and an ethylene-.alpha.-olefin-polyene amorphous copolymer (B) containing as the polyene component a norbornene compound having at least one kind of vinyl terminal group represented by 5-vinyl-2-norbornene or 5-methylene-2-norbornene. The rubber composition is speedily cured, if said components (A) and (B) are mixed by the A/B mixing ratio of 98/2-2/98 (% by weight) and kneaded in the presence of an organic peroxide. A vulcanizate rubber excelling in mechanical strength, water resistance and thermal aging resistance can be manufactured from said composition, since its crosslink density can be enhanced without impairing processing properties. Additionally, said composition entails reduced mold fouling phenomenon in the molding operation. Vulcanizate rubber thereby obtained can be advantageously used as industrial parts and electric parts.

Curable rubber composition

Rubber composition and process for the production thereof

Disclosed is a foam processable rubber composition which comprises an ethylene/.alpha.-olefin of 3 to 20 carbon atoms/non-conjugated polyene copolymer rubber (A), a crystalline polyolefin resin (B) having a melting point of 100 to 150.degree. C. and a foaming agent (C), in specific proportions. The copolymer rubber (A) has an ethylene/.alpha.-olefin molar ratio of 60/40 to 80/20, an intrinsic viscosity (.eta.), as measured in decalin at 135.degree. C., of 0.7 to 2 dl/g, and an iodine value of 10 to 50. A vulcanized rubber foam-molded product can be obtained by vulcanizing and foaming the rubber composition. The rubber composition can provide vulcanized rubber foam-molded products having excellent vulcanization properties such as weathering resistance, heat resistance, ozone resistance and tear strength. Besides, the rubber composition exhibits excellent precision moldability and productivity of vulcanized rubber foam-molded products in transfer molding, injection molding and cast molding.

Foam processable rubber compositions and vulcanized rubber foam molded

A terpolymer rubber prepared from ethylene, .alpha.-olefin having 3 to 20 carbon atoms and branched chain polyene of the formula ##STR1## wherein R.sup.1 represents C.sub.1 -C.sub.5 alkyl, and R.sup.2 and R.sup.3 represent hydrogen atom or C.sub.1 -C.sub.5 alkyl, such as, for example, 6,7-dimethyl-4-ethylidene-1,6-octadiene, 6,7-dimethyl-4-ethylidene-1,6-nonadiene, and 9-methyl-4-ethylidene-1,8-decadiene; when added to a rubber (diene rubber, nitrile rubber or random copolymer rubber from ethylene, C.sub.3 -C.sub.20 .alpha.-olefin, and optionally a nonconjugated diene) provides curable rubber compositions having rapid vulcanization rates, for example, as lows as about 7 to 10 seconds. The diene rubber compositions also have excellent resistances to weather,ozone and heat aging while maintaining excellent mechanical strength characteristics. The nitrile rubber compositions also have excellent oil resistance.

Ethylene/.alpha.-olefin/nonconjugated polyene terpolymer rubber

The ethylene/.alpha.-olefin/nonconjugated polyene copolymer rubber composition of the present invention comprises in specified proportions a crystalline polyolefin resin (A) and an ethylene/.alpha.-olefin/nonconjugated polyene copolymer rubber (B) composed of ethylene, an .alpha.-olefin having 3 to 20 carbon atoms and a specific branched chain polyene compound. The molar ratio of ethylene units to .alpha.-olefin units, iodine value and intrinsic viscosity �.eta.! of the ethylene/.alpha.-olefin/nonconjugated polyene copolymer rubber (B) are within respective specified ranges. This rubber composition is excellent in low temperature properties. When the above olefinic thermoplastic elastomer composition is partially or entirely crosslinked, a molding can be provided which is superior to the conventional vulcanized rubbers in low temperature properties, tensile strength, elongation at break and rubber properties.

Ethylene/.alpha.-olefin/nonconjugated polyene copolymer rubber

Disclosed is a process for preparing an ethylene-.alpha.-olefin-nonconjugated polyene random copolymer comprising random copolymerizing (a) ethylene, (b) an .alpha.-olefin of 3 or more carbon atoms and (c) a nonconjugated polyene in the presence of a metallocene catalyst containing a specific metallocene compound. The ethylene-.alpha.-olefin-nonconjugated polyene random copolymer prepared by the process has such properties that (i) the copolymer contains units derived from ethylene (a) and units derived from the .alpha.-olefin of 3 or more carbon atoms (b) in a molar ratio of 40/60 to 95/5 �(a)/(b)!, (ii) the iodine value is 1 to 50, (iii) the intrinsic viscosity (.eta.) is more than 0.1 dl/g and less than 8.0 10 dl/g, (iv) the intensity ratio D of T.alpha..beta. to T.alpha..alpha. in the .sup.13 C-NMR spectrum, T.alpha..beta./T.alpha..alpha., is not more than 0.5, (v) the B value is 1.00 to 1.50, (vi) the glass transition temperature Tg is not higher than -50.degree. C., and (vii) the ratio g.eta.* of the intrinsic viscosity (.eta.) of this copolymer defined above to the intrinsic viscosity (.eta.).sub.blank of a straight-chain ethylene-propylene copolymer having the same weight-average molecular weight as this random copolymer and having an ethylene content of 70% by mol, (.eta.)/(.eta.).sub.blank, is more than 0.9. Also disclosed is a vulcanizable rubber composition containing the random copolymer. The ethylene-.alpha.-olefin-nonconjugated polyene random copolymer and the rubber composition are excellent in mechanical strength, weathering resistance, ozone resistance, processability, low-temperature flexibility and heat resistance.

Vulcanizable rubber composition containing

Growing community of inventors

Ichihara, Japan

Tetsuo Tojo