Abstract: The present invention provides olefin polymerization catalysts and processes for preparing a polypropylene and a propylene block copolymer using said olefin polymerization catalysts.The olefin polymerization catalyst (1) of the invention is formed from:[I-1] a contact product obtained by contacting:(A) a solid titanium catalyst component,(B) an organometallic compound catalyst component, and(C) a specific organosilicon compound;[II-1] (D) a specific polyether compound; and optionally,[III] an organometallic compound catalyst component.The olefin polymerization catalyst (2) of the invention is formed from:[I-2] a contact product obtained by contacting:(A) a solid titanium catalyst component,(B) an organometallic compound catalyst component, and(D) a specific polyether compound;[11-2] (C) a specific organosilicon compound.

Abstract: Disclosed are a polypropylene resin composition comprising a crystalline polypropylene having a high stereoregularity and a terpene resin and a petroleum resin each having no polar group; a polypropylene stretched film formed from the polypropylene resin composition; and a polypropylene multi-layer stretched film having a base layer formed from the polypropylene resin composition and a surface layer formed from a polypropylene type polymer. The polypropylene stretched film and a polypropylene multi-layer stretched film have excellent water-vapor barrier properties and transparency, and a high Young's modulus.

Abstract: Disclosed are a polypropylene resin composition comprising a crystalline polypropylene having a high stereoregularity and a terpene resin and a petroleum resin each having no polar group; a polypropylene stretched film formed from the polypropylene resin composition; and a polypropylene multi-layer stretched film having a base layer formed from the polypropylene resin composition and surface layer formed from a polypropylene type polymer. The polypropylene stretched film and a polypropylene multi-layer stretched film have excellent water-vapor barrier properties and transparency, and a high Young's modulus.

Abstract: Disclosed are a polypropylene resin composition comprising a crystalline polypropylene having a high stereoregularity and a terpene resin and a petroleum resin each having no polar group; a polypropylene stretched film formed from the polypropylene resin composition; and a polypropylene multi-layer stretched film having a base layer formed from the polypropylene resin composition and a surface layer formed from a polypropylene type polymer. The polypropylene stretched film and a polypropylene multi-layer stretched film have excellent water-vapor barrier properties and transparency, and a high Young's modulus.

Abstract: The olefin polymer composition according to the invention comprises [I] an (.alpha.-olefin/polyene copolymer-containing polymer in an amount of 0.005 to 99 by weight, said .alpha.-olefin/polyene copolymer-containing polymer comprising (i) an .alpha.-olefin/polyene copolymer and (ii) a polyethylene, and [II] a polyethylene in an amount of 1 to 99.995% by weight. The olefin polymer composition comprising the .alpha.-olefin/polyene copolymer-containing polymer [I] and the olefin polymer [II] has a high melt tension and an excellent moldability in an inflation molding, and further it can be molded into a large sized container, etc. by means of a blow molding or the like.

Abstract: The olefin polymer of the invention is an .alpha.-olefin/polyene copolymer-containing olefin polymer comprising (i) an .alpha.-olefin/polyene copolymer and (ii) an olefin polymer,wherein the polyene is an aliphatic polyene having 7 or more carbon atoms and having an olefinic double bond at both terminals, and the .alpha.-olefin/polyene copolymer contains constituent units derived from the .alpha.-olefin in an amount of 99.999 to 70 mol % and contains constituent units derived from the polyene in an amount of 0.001 to 30 mol %,the olefin polymer (ii) is a polymer of olefin having 3 or more carbon atoms,the .alpha.-olefin/polyene copolymer-containing olefin polymer comprises the .alpha.-olefin/polyene copolymer (i) in an amount of 0.001 to 15% by weight and the olefin polymer (ii) in an amount of 99.999 to 85% by weight, andthe .alpha.-olefin/polyene copolymer-containing olefin polymer is obtained by using a prepolymerized catalyst containing the .alpha.-olefin/polyene copolymer.

Abstract: The olefin polymer composition according to the invention comprises [I] an .alpha.-olefin/polyene copolymer-containing polymer in an amount of 0.005 to 99 by weight, said .alpha.-olefin/polyene copolymer-containing polymer comprising (i) an .alpha.-olefin/polyene copolymer and (ii) a polypropylene, and [II] a polymer of .alpha.-olefin having 3 or more carbon atoms in an amount of 1 to 99.995% by weight. The olefin polymer composition comprising the .alpha.-olefin/polyene copolymer-containing polymer [I] and the olefin polymer [II] has a high melt tension and an excellent moldability in an inflation molding, and further it can be molded into a large sized container, etc. by means of a blow molding or the like.