This invention relates to compositions of matter which are useful as addition polymerization catalysts, to a method for preparing these catalyst compositions and to a method of using these catalyst compositions. More particularly, this invention relates to improved olefin polymerization catalyst compositions comprising a Group 4 metal complex, an activator therefor, and a Group 13 aromatic amide tertiary component. The invention also relates to an improved method for polymerizing addition polymerizable monomers using these catalyst compositions.
Constrained geometry metal complexes, their preparation, methods of activation, active catalysts formed therefrom including cationic catalysts and methods of use are disclosed in EP-A-416,815; EP-A-514,828; EP-A-520,732; U.S. Pat. No. 5,064,802; U.S. Pat. No. 5,374,696; U.S. Pat. No. 5,470,993; U.S. Pat. No. 5,055,438, U.S. Pat. No. 5,057,475, U.S. Pat. No. 5,096,867, U.S. Pat. No. 5,064,802, U.S. Pat. No. 5,132,380, and U.S. Pat. No. 5,453,410.
Although previously known active catalysts, especially the cationic catalysts disclosed in the foregoing applications and publications, have excellent activity they are extremely sensitive to catalyst poisons, such as polar impurities, that may be contained in a polymerization mixture. Because of this fact, catalyst efficiencies and lifetimes have been limited and molecular weights of the resulting polymers have been reduced. In addition, it has now been observed that certain tertiary substances that are added to the reaction mixture to improve catalyst efficiency disadvantageously result in the formation of increased levels of a polymer fraction having high crystallinity. Such high crystallinity fractions (HCF) may result in fouling of the reactor and are desirably eliminated or at least reduced in order to increase production efficiency and product uniformity.
It is previously known in the art to utilize adjuvants such as trialkylboron compounds, trialkylaluminum compounds, dialkylaluminum alkoxides and dialkylaluminum N,N-di(hydrocarbyl)amides to remove catalyst poisons from various olefin polymerization catalysts. Examples of such compositions are contained in U.S. Pat. No. 6,074,977, U.S. Pat. No. 6,017,842, U.S. Pat. No. 5,206,199, U.S. Pat. No. 5,962,599, U.S. Pat. No. 6,268,063 and U.S. Pat. No. 6,353,063. Disadvantageously however, such adjuvants have proven to be less effective in combating the inhibition of catalytically activated constrained geometry catalysts, and have not demonstrated reduced HCF formation or reduced reactor fouling.
The present investigations have led to certain improved catalyst compositions that are highly active as addition polymerization catalysts, desirably having improved resistance to catalyst poisons with reduced production of high crystalline fraction polymers.