| abstract |
A catalyst composition comprising A) an aluminoxane-impregnated support prepared by contacting an aluminoxane with an inert carrier material and heating to a temperature of at least about 80 DEG C.; B) a metallocene of the formula: (L)y(L')MY(x-y-1) wherein M is a metal from groups IIIB to VIII of the Periodic Table; each L and L' is independently a cycloalkadienyl group bonded to M; each Y is independently hydrogen, an aryl, alkyl, alkenyl, alkylaryl, or arylalkyl radical having 1-20 carbon atoms, a hydrocarboxy radical having from 1-20 carbon atoms, a halogen, RCO2-, or R2N-, wherein R is a hydrocarbyl group containing 1 to about 20 carbon atoms; n and m are each 0, 1, 2, 3, or 4; y is 0, 1, or 2; x is 1, 2, 3, or 4; and x-y>/=1; C) a bulky aluminum alkyl of the formula: AlR1xR2(3-x) wherein R1 is a hydrocarbyl group having 1 to 12 carbon atoms; x is an integer from 0 to 2; R2 is a hydrocarbyl group of the formula -(CH2)y- R3, wherein y is an integer from 1 to 8; and R3 is a saturated or unsaturated hydrocarbyl group having 3 to 12 carbon atoms containing at least one ring, and D) methylaluminoxane is provided. The catalyst composition may be used to prepare olefin polymers having increased short chain branching frequency. |