Abstract: Disclosed is a solid titanium catalyst component which is obtained by a process comprising the steps of bringing (a) a liquid magnesium compound into contact with (b) a liquid titanium compound in the presence of (c) an organosilicon compound having no active hydrogen in an amount of 0.25 to 0.35 mol based on 1 mol of the magnesium compound (a), elevating the temperature of the resulting contact product to a temperature of 105 to 115° C. and maintaining the contact product at this temperature. The contact product may be further brought into contact with not more than 0.5 mol of the organosilicon compound having no active hydrogen (c). Also disclosed are an ethylene polymerization catalyst formed from the solid titanium catalyst component and an organometallic compound and an ethylene polymerization process using the catalyst. By the use of the solid titanium catalyst component, ethylene can be polymerized with high activities and an ethylene polymer having excellent particle properties can be prepared.

Abstract: A process for preparing an ethylene polymer composition comprises a step (I) to prepare an ethylene (co)polymer (i) having [&eegr;] of at least 1.5 times the intrinsic viscosity of a (co)polymer (ii) and a step (II) to prepare an ethylene (co)polymer (ii) having [&eegr;] of 0.3 to 3 dl/g, said steps (I) and (II) using a catalyst containing a component obtained by contacting a liquid Mg compound with a liquid Ti compound in the presence of an organosilicon compound, wherein the step (II) is carried out in the presence of the polymer (i) or the step (I) is carried out in the presence of the polymer (ii), to prepare an ethylene polymer composition having [&eegr;] of 1 to 6 dl/g and a density of not less than 0.94 g/cm3.

Abstract: A process for preparing an ethylene polymer composition comprises a step (I) to prepare an ethylene (co)polymer (i) having [i] of at least 1.5 times the intrinsic viscosity of a (co)polymer (ii) and a step (II) to prepare an ethylene (co)polymer (ii) having [&eegr;] of 0.3 to 3 dl/g, said steps (I) and (II) using a catalyst containing a component obtained by contacting a liquid Mg compound with a liquid Ti compound in the presence of an organosilicon compound, wherein the step (II) is carried out in the presence of the polymer (i) or the step (I) is carried out in the presence of the polymer (ii), to prepare an ethylene polymer composition having [&eegr;] of 1 to 6 dl/g and a density of not less than 0.94 g/cm3.

Abstract: Disclosed is a solid titanium catalyst component which is obtained by a process comprising the steps of bringing (a) a liquid magnesium compound into contact with (b) a liquid titanium compound in the presence of (c) an organosilicon compound having no active hydrogen in an amount of 0.25 to 0.35 mol based on 1 mol of the magnesium compound (a), elevating the temperature of the resulting contact product to a temperature of 105 to 115° C. and maintaining the contact product at this temperature. The contact product may be further brought into contact with not more than 0.5 mol of the organosilicon compound having no active hydrogen (c). Also disclosed are an ethylene polymerization catalyst formed from the solid titanium catalyst component and an organometallic compound and an ethylene polymerization process using the catalyst. By the use of the solid titanium catalyst component, ethylene can be polymerized with high activities and an ethylene polymer having excellent particle properties can be prepared.

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 invention provides a process for preparing a solid titanium catalyst component for use in the preparation of an olefin polymerization catalyst, which comprises: (1) a step wherein a suspension is prepared which contains a solid material prepared by contacting a magnesium compound with a first titanium compound and having a polybasic carboxylic acid ester supported thereon; (2) a step wherein the solid material is separated from the suspension; and (3) a step wherein the solid material is contacted with a second titanium compound under heating; wherein while the solid material is separated from the suspension in the step (2) and the solid material is supplied to the step (3), the solid material is maintained at a temperature in the range of 70-130° C.

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 titanium catalyst component for ethylene polymerization obtained by contacting [A] a solid magnesium aluminum complex containing magnesium, halogen, aluminum and an alkoxy group and/or alcohol having at least 6 carbon atoms, with [B] a tetravalent titanium compound. The solid magnesium aluminum complex [A] is obtained by contacting (a-1) a magnesium solution formed from a halogen-containing magnesium compound, an alcohol having at least 6 carbon atoms and a hydrocarbon solvent, with (a-2) an organoaluminum compound. Also disclosed is a process for ethylene polymerization comprising polymerizing ethylene or copolymerizing ethylene with an .alpha.-olefin having 3 to 20 carbon atoms in the presence of a catalyst for ethylene polymerization comprising [I] the above-mentioned titanium catalyst component for ethylene polymerization and [II] an organoaluminum compound catalyst component.

Abstract: Disclosed is a titanium catalyst component for ethylene polymerization obtained by contacting [A] a solid magnesium aluminum complex containing magnesium, halogen, aluminum and an alkoxy group and/or alcohol having at least 6 carbon atoms, with [B] a tetravalent titanium compound. The solid magnesium aluminum complex [A] is obtained by contacting (a-1) a magnesium solution formed from a halogen-containing magnesium compound, an alcohol having at least 6 carbon atoms and a hydrocarbon solvent, with (a-2) an organoaluminum compound. Also disclosed is a process for ethylene polymerization comprising polymerizing ethylene or copolymerizing ethylene with an .alpha.-olefin having 3 to 20 carbon atoms in the presence of a catalyst for ethylene polymerization comprising [I] the above-mentioned titanium catalyst component for ethylene polymerization and [II] an organoaluminum compound catalyst component.

Abstract: The present invention relates to a novel ethylene/pentene-1 copolymer whose molded film has a good balance between impact resistance and tear properties and high transparency, also is prominently reduced in a variation of the transparency even after subjected to a heat treatment, and further shows high blocking resistance, provided that the copolymer fulfills specific requisites. The invention also relates to a process for the preparation of the above-mentioned ethylene/pentene-1 copolymer and a formulation of the ethylene/pentene-1 copolymer composition using a stabilizer. According to the invention, there can be obtained an ethylene/pentene-1 copolymer composition which is excellent in heat stability in the molding stage, long-term heat stability and weatherability.