Abstract: A modified supported catalyst for polymerizing alpha-olefins, for example, ethylene, is prepared by combining a chromium compound-containing catalyst with a modifier which is an oxide of an element of Group II A of the Periodic Chart of the Elements. The resulting modified catalyst composition, when used to polymerize alpha-olefins, produces polymer resins having higher values of High Load Melt Index (I.sub.21) than catalyst compositions without the modifier.There is also disclosed a process for polymerizing alpha-olefins, at relatively lower temperatures than was heretofore possible, to obtain resins of relatively high HLMI, using the above-identified modified catalyst composition. The resulting polymers can be used for the fabrication of blow-molded products, e.g., household and industrial containers.

Abstract: A modified catalyst for polymerizing alpha-olefins, for example, ethylene, is prepared by combining a chromium-compound-comprising catalyst, supported on a refractory oxide support with at least one catalyst modifier of the formula R Mg R' where R and R' are the same or different C.sub.1 -C.sub.12 hydrocarbyl, alkoxy, alkenoxy or aryloxy groups. The amount of the modifier is such that the modified catalyst composition has the molar ratio of magnesium to chromium of about 0.2 to about 1.25. The modified catalyst composition produces resins of relatively high HLMI at relatively low temperatures.There is also disclosed a process for polymerizing alpha-olefins, at relatively lower temperatures than was heretofore possible, to obtain resins of relatively high HLMI, using the modified catalyst composition. The resulting polymers can be used for the fabrication of blow-molded products, e.g., household and industrial containers.

Abstract: A modified supported catalyst for polymerizing alpha-olefins, for example, ethylene, is prepared by combining a chromium compound-containing catalyst with a modifier which is an oxide of an element of Group II A of the Periodic Chart of the Elements. The resulting modified catalyst composition, when used to polymerize alpha-olefins, produces polymer resins having higher values of High Load Melt Index (I.sub.21) than catalyst compositions without the modifier.There is also disclosed a process for polymerizing alpha-olefins, at relatively lower temperatures than was heretofore possible, to obtain resins of relatively high HLMI, using the above-identified modified catalyst composition. The resulting polymers can be used for the fabrication of blow-molded products, e.g., household and industrial containers.