Abstract: A propylene-ethylene block copolymer composition is disclosed which comprises 0.01 to 10% by weight of an A-B type propylene-ethylene block copolymer (C) consisting essentially of a polypropylene segment (A) and an ethylene-propylene random copolymer segment (B), and 99.99 to 90% by weight of a propylene polymer (D), wherein the A-B type propylene-ethylene block copolymer (C) comprises 5 to 80% by weight of the ethylene-propylene random copolymer segment (B) having an ethylene content of 10 to 90% by weight and the propylene polymer (D) comprises 60 to 95% by weight of a homopolymer of propylene or a copolymer of propylene containing a copolymerizable monomer therewith (D1) and 40 to 5% by weight of an ethylene-propylene random copolymer (D2).

Abstract: A propylene-ethylene block copolymer composition is disclosed which comprises 0.

Abstract: A propylene-ethylene block copolymer composition is disclosed which comprises 0.01 to 10% by weight of an A-B type propylene-ethylene block copolymer (C) consisting essentially of a polypropylene segment (A) and an ethylene-propylene random copolymer segment (B), and 99.99 to 90% by weight of a propylene polymer (D), wherein the A-B type propylene-ethylene block copolymer (C) comprises 5 to 80% by weight of the ethylene-propylene random copolymer segment (B) having an ethylene content of 10 to 90% by weight and the propylene polymer (D) comprises 60 to 95% by weight of a homopolymer of propylene or a copolymer of propylene containing a copolymerizable monomer therewith (D1) and 40 to 5% by weight of an ethylene-propylene random copolymer (D2).

Abstract: A modified propylene polymer having superior coloring-prevention properties is provided by a process which comprises blending a propylene polymer with (A) a polyol or a fatty acid partial ester of the polyol (B) a phenolic antioxidant and (C) a radical generating agent with a propylene polymer containing 5 ppm or more of titanium or 0.5 ppm or more of vanadium as a catalyst residue and subjecting the resultant blend to a melting and kneading treatment at a temperature of 150.degree. C.-300.degree. C.

Abstract: A process for producing a modified propylene polymer composition is disclosed, which comprises melt-kneading a propylene polymer having a considerable titanium or vanadium content as a catalyst residue and having incorporated therein a phenolic antioxidant in the presence of a radical generator in combination with a specific amount of a zinc salt of a carboxylic acid. The resulting modified propylene polymer composition exhibits freedom from coloring as well as improved moldability.

Abstract: 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.

Abstract: 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):Al.sub.x Si.sub.y (OH).sub.3x+4y.nH.sub.2 O (1)Mg.sub.x (OH).sub.2y-2x (CO.sub.3).sub.y.nH.sub.2 O (2)Mg.sub.x Ca.sub.y (CO.sub.3).sub.2x+2y/2.nH.sub.2 O (3)M.sub.x Si.sub.y (OH).sub.2x+4y.nH.sub.2 O (4)M.sub.x Al.sub.y Si.sub.z (OH).sub.2x+3y+4z.nH.sub.2 O (5)M.sub.x Al.sub.y (OH).sub.2x+3y-2z (A).nH.sub.2 O (6)where M represents Mg or Ca; A represents CO.sub.3, HPO.sub.4 or SO.sub.4 ; x, y and z represent a positive number; and n represents zero or a positive integer; calcined products therefrom, and hydrates thereof. The deodorizer may be added thereto independently from or concurrently with other additives to be mixed.

Abstract: 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.

Abstract: 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.