| 摘要 |
Provided are a catalyst composition showing an improved catalytic activity, a method for preparing the catalyst composition, a method for an olefin polymer by using the catalyst composition, and an olefin polymer prepared by the method which has an ultralow density less than 0.910 g/cc. The catalyst composition comprises a precatalyst of a transition metal compound represented by the formula 1; a first co-catalyst of an alkyl aluminum compound represented by Al(R6)3; and a second co-catalyst of a salt of a Broensted acid cation and an uncoordinated anion represented by [L-H]+[ZA4]-, wherein R1 and R2 are independently H, a C1-C20 alkyl, aryl or silyl group, a C1-C20 alkenyl, alkylaryl or arylalkyl group, or a metalloid group of a group 14A metal substituted with a hydrocarbyl group, or R1 and R2 can be linked by an alkylidyne group containing a C1-C20 alkyl or aryl group to form a ring; R3 is a C1-C20 alkyl, aryl or silyl group, a C1-C20 alkenyl, alkylaryl or arylalkyl group, or a metalloid group of a group 14A metal substituted with a hydrocarbyl group; R4 are independently H, a halogen atom, or a C1-C20 alkyl or aryl group, and two R4 can be linked each other; E is a covalent bridging group connecting the two phenylene rings and is an epoxy group, an epithio group, a carbonyl group, a silane group, a disilane group, a substituted or unsubstituted C1-C60 hydrocarbylene group, or a substituted or unsubstituted C1-C60 heterohydrocarbylene group containing an element of group 4B, 5B or 6B; M is Ti, Zr or Hf; Q1 and Q2 are independently a halogen atom a C1-C20 alkyl or arylamide group, a C1-C20 alkyl, alkenyl, aryl, alkylaryl or arylalkyl group, or a C1-C20 alkylidene group; R6 is a C1-C20 hydrocarbyl group substituted or unsubstituted with a halogen atom; L is a neutral Lewis base; [L-H]+ is a Broensted acid; Z is boron or aluminum of +3 oxidation state; and A are independently a C6-C20 alkyl group whose at least one hydrogen atom is substituted with a halogen atom, a C1-C20 hydrocarbyl group, an alkoxy group or a phenoxy group.
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