PURPOSE: To obtain a Ziegler-Natta type catalyst system suitable for producing ethylene polymers having a reduced hexane extractable content by using a titanium trichloride component obtained by a specific treatment of titanium tetrachloride.
CONSTITUTION: A titanium trichloride component is prepared by reducing titanium tetrachloride to titanium trichloride by magnesium metal in an electron donor solvent free of a radical containing an active hydrogen, reducing the titanium trichloride by the treatment with a stoichiometric amount of magnesium metal necessary to form magnesium dichloride, adding magnesium dichloride to the resulting solution to increase the ratio of Mg to Ti in the range of 1:1 to 56:1 and subsequently, impregnating a support with the resulting solution or spray-drying the solution which contains or does not, contain a filler to obtain separated catalyst particles. A desired catalyst system comprises the titanium trichloride component thus prepared and an organoaluminum component.
ERUTON DOIRU FUAURAA
JIYOOJI RENAADO GEEKE
