Abstract: Crystalline polypropylene contains components insoluble in 64° C. decane satisfying the characteristics involving intrinsic viscosity; Mz/Mn; pentadvisotacticity, D value and Mw/Mn, are excellent in hardness and rigidity, high in melt tension, and excellent in molding properties. Processes for preparing such crystalline polypropylenes, and polypropylene compositions and thermoformed products that contain such crystalline polypropylenes are also described. The number-average molecular weight Mn of the components insoluble in 64° C. decane is preferably 25000 or more.

Abstract: Disclosed is a process for preparing a solid titanium catalyst component, comprising the steps of (I) contacting a liquid magnesium compound with a liquid titanium compound to precipitate a solid in the contact liquid (&bgr;), and adding an electron donor (d-i) selected from the group consisting of a polycarboxylic ester and a polyether compound to the contact liquid (&bgr;) during the time from beginning to end of the solid precipitation, to form a solid product (&agr;); and (II) contacting the solid product (&agr;) obtained after completion of the solid precipitation with an electron donor (d-ii) selected from the group consisting of a polycarboxylic ester and a polyether compound, to prepare a solid titanium catalyst component. According to the process, a solid titanium catalyst component capable of polymerizing an olefin with high activity and capable of preparing an olefin polymer of high stereoregularity can be prepared.

Abstract: The present invention presents crystalline polypropylenes that contain components insoluble in 64° C. decane that satisfy the following characteristics (1) to (4) and are excellent in hardness and rigidity, high in melt tension, and excellent in molding properties, process for preparing such crystalline polypropylenes, and polypropylene compositions and thermoformed products that contain such crystalline polypropylenes.

Abstract: The present invention intends to provide a process for preparation of a solid titanium catalyst component for an olefin polymerization excellent in polymerization activity per unit catalyst, and a process for preparation of a polyolefin using a catalyst containing the catalyst component. The process according to the present invention is characterized by comprising the steps of contacting (A) a magnesium compound with (B) a solution titanium compound to obtain a solid titanium catalyst component composed of titanium, magnesium and a halogen as the essential components, wherein a titanium compound mixture liquid composed of 88 to 99% by weight of a titanium compound and 1 to 12% by weight of hydrocarbon containing halogen-containing hydrocarbon is used as (B) the solution titanium compound.

Abstract: Disclosed is a process for preparing a solid titanium catalyst component, comprising contacting (a) a liquid magnesium compound, (b) a liquid titanium compound, (c) an electron donor and (d) a solid divalent metallic halide. In this process, the solid divalent metallic halide is one having a crystalline structure of the cadmium chloride type. The contact of the component (a) with the component (b) is preferably carried out in the presence of the solid divalent metallic halide (d). According to this process, there can be obtained a solid titanium catalyst component capable of polymerizing olefins with an extremely high activity and capable of producing polyolefins of high stereoregularity when .alpha.-olefins of 3 or more carbon atoms are polymerized.