A catalyst for the production of an ethylene polymer comprising a specific trivalent alkyl chromium compound, an inorganic oxide solid and optionally an organoaluminum compound (first catalyst), a catalyst for the production of an ethylene polymer comprising the specific trivalent alkyl chromium compound, a specific tetravalent alkyl chromium compound and an inorganic oxide solid (second catalyst) and a process for producing an ethylene polymer using those catalysts. The first catalyst of the present invention does not cause deterioration with the passage of time, is stable to heat and light, has greatly improved activity and can efficiently produce an ethylene copolymer with &agr;-olefin. The second catalyst of the present invention can efficiently produce an ethylene polymer having low molecular weight and narrow molecular weight distribution suitable for use in injection molding or an ethylene polymer having excellent balance between rigidity and ESCR and also excellent moldability suitable for use in blow molding or film molding.
本发明提供了生产
乙烯聚合物的催化剂,包括特定的三价烷基
铬化合物、无机氧化物固体和可选的
有机铝化合物(第一催化剂),以及生产
乙烯聚合物的催化剂,包括特定的三价烷基
铬化合物、特定的四价烷基
铬化合物和无机氧化物固体(第二催化剂),以及使用这些催化剂生产
乙烯聚合物的方法。本发明的第一催化剂不会随着时间的推移而导致恶化,对热和光稳定,活性显著提高,并且能够高效地生产具有α-烯烃的
乙烯共聚物。本发明的第二催化剂能够高效地生产分子量低、分子量分布窄的
乙烯聚合物,适用于注塑,或者具有良好的刚度和ESCR平衡以及出色的成型性,适用于吹塑或薄膜成型。