Chisso Corporation

Takeshi Suzuki

Nobutoshi Komori

Hiromasa Chiba

Atsuyoshi Shimizu

Hiroshi Shimizu

Akihiro Sato

Kazutsune Kikuta

Toshihiro Uwai

Takehiko Takahashi

Kenji Matsuda

Tohru Hanari

Tsutomu Takahashi

Takashi Koizumi

Masamitsu Iwasaki

Kazumasa Shibata

Ryohichi Yasunaga

Hironaka Sekine

Isoo Shirai

Takehiro Umeno

A polypropylene composite stretched film having superior low-temperature heat-sealing characteristics, transparency and anti-block properties is provided, which film comprises as a base layer, a crystalline polypropylene and as a heat-sealing layer, a crystalline ethylene-propylene random copolymer containing 1 to 5% by weight of polymers having a molecular weight (Mw) of 6,000 or less and 3 to 5% by weight of ethylene, or a crystalline ethylene-propylene-butene-1 copolymer containing 1 to 5% by weight of polymers having a Mw of 6,000 or less, 1 to 10% by weight of ethylene and 4 to 30% by weight of butene-1.

Polypropylene composite stretched film

Purified polyolefins prepared by deactivating Ziegler type catalyst residue contained in polyolefins not purified by use of alkylene oxide and having off-odor are mixed for deodorization with 0.001 to 0.5% by weight of at least one deodorizer selected from the compounds having the following formulas (1) to (6):

Deodorized polyolefins and process for the preparation thereof

Devolatilization of sticky polyolefin powder and deactivation of catalyst residue can be carried out efficiently and sufficiently without the need for accompanying facilities commonly used in the treatment of powdery products in an apparatus comprising (a) a horizontal cylindrical body, (b) a stirrer provided with one revolving shaft and a plurality of specified stirring blades (c) an inlet pipe for introducing untreated polyolefin power and heating gas, (d) a variable barrage for controlling the holding amount of polyolefin powder insides of said horizontal cylindrical body, (e) an outlet way for discharging after-treated polyolefin powder and gas, (f) inlet pipes for heating gas having a pipe for feeding an after-treating agent, and (g) indirect heating mean.

Apparatus for after-treating polyolefin powder

A process for producing ethylene-propylene block copolymer by the use of a catalyst employed for producing isotactic polypropylene is provided. This process is characterized in that a gas phase polymerization of propylene is substantially carried out in the presence of the catalyst obtained by combining a titanium trichloride composition with an average particle size of 10.about.100 .mu. and an organic aluminum to form the propylene polymer segment with a specific surface area more than 0.015 m.sup.2 /g at a yield of more than 3,000 g per 1 g of the titanium trichloride composition in the first step, and then a gas phase polymerization of a mixture of polypropylene and ethylene is successively carried out in the second step to form the copolymer segment with a copolymerization ratio of propylene:ethylene being 5.about.80 weight %:95.about.20 weight %, wherein the polymerized amount of the second step is 10-40% of total polymerized amount and wherein normal hexane extraction ratio (75.degree. C., 1 hour) of the ethylene-propylene block copolymer powders obtained is 1.about.10 weight %. The process of the present invention is one having an extremely high productivity industrially, and the modified polypropylene obtained has a superior low-temperature-impact strength and brittle temperature.

Process for producing modified polypropylene

A process for producing terpolymers of propylene (as a main monomer), ethylene and another .alpha.-olefin having superior and well-balanced physical properties, almost without forming soluble polymer is provided. This process is characterized by preliminarily activating a catalyst consisting of a titanium trichloride composition and a specified organoaluminum halide, with a small amount of an .alpha.-olefin of 2 to 12 carbon atoms, a trialkylaluminum and an aromatic ester, and copolymerizing specified amounts of propylene, ethylene and an .alpha.-olefin of 4 to 12 carbon atoms in the presence of the preliminarily activated catalyst obtained above.

Process for producing terpolymers of propylene, ethylene and another .alpha

A method for producing crystalline copolymers of propylene (major component), ethylene and an .alpha.-olefin having 4 to 12 carbon atoms, superior in any of various practical physical properties such as cold-resistance, transparency, heat-seal temperature, percentage shrinkage, etc. is provided, wherein a catalyst solution obtained by mixing together a titanium trichloride composition (obtained by mixing and milling a titanium trichloride with a mixed reaction product of TiCl.sub.4 with an ether), a dialkylaluminum halide, an electron-donor compound and an inert solvent, is activated in advance of copolymerization, by feeding propylene into the solution under specified feeding conditions, and copolymerization is carried out by feeding propylene and said .alpha.-olefin simultaneously and continuously, while feeding ethylene intermittently into the gas phase part of the polymerization zone containing the solution.

Method for producing propylene copolymers using a catalyst activated

A process for producing a modified polypropylene by copolymerizing propylene with ethylene in the presence of a Ziegler-Natta catalyst is provided. This process consists of the following three steps:

Process for producing propylene-ethylene copolymers

A method for activating a catalyst for propylene polymerization before polymerization is proposed. According to this method, a catalyst which has stability at the time of use and reduces the ratio of amorphous polymer at the time of polymerization is obtained. Said method comprises causing a catalyst dispersion prepared by mixing a specified .delta.-type titanium trichloride composition and an alkylaluminum trichloride in an inert solvent and maintained at a temperature of 10.degree. to 50.degree. C, to absorb a small amount of propylene in an amount of 0.5 to 5 times by weight that of said .delta.-type titanium trichloride.

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Ichiharashi, Japan

Takeshi Suzuki