Transition metal catalytic systems and methods for preparing ethylene homopolymers or copolymers of ethylene and olefins using the same
Disclosed herein is a group IV transition metal catalyst for producing an ethylene homopolymer or an ethylene-olefin copolymers, having high catalytic activity, which includes a cyclopentadiene derivative and one or more anionic ligands having an aryl group substituted with an aryl derivative at an ortho-position thereof around a transition metal, the ligands not being crosslinked to each other, a catalyst system including the group IV transition metal catalyst and an aluminoxane cocatalyst or a boron compound cocatalyst, and a method of producing ethylene homopolymers or ethylene-olefin copolymers using the catalyst system.
1. A method of producing an ethylene homopolymer at a polymerization temperature of 60˜250° C. using the transition metal system comprising;
(a) a transition metal catalyst system;
represented by Formula 1 below, which includes a cyclopentadiene derivative and one or more anionic ligands having an aryl group substituted with an aryl derivative at an ortho-position thereof around a transition metal, the ligands not being crosslinked to each other:
wherein M is titanium;
Cp is cyclopentadienyl or pentamethylcyclopentadienyl group which forms a η5-bond with the central metal M;
D is N—R 1 , in which R 1 is a hydrogen atom or an aryl group of 6 to 30 carbon atoms;
R 2 , R 3 , and R 4 are a hydrogen atom;
R 5 , R 6 , R 7 , R 8 and R 9 are each independently a hydrogen atom, a linear or nonlinear alkyl group of 1 to 20 carbon atoms, an aryl group of 6 to 30 carbon atoms, or an alkoxy group selected from a methoxy group, ethoxy group, isopropoxy group, and tert-butoxy group, and R 5 , R 6 , R 7 , R 8 and R 9 may be arbitrarily bonded with each other to form rings;
E is C—R 10 , in which R 10 is a hydrogen atom;
n is an integer of 1 or 2; and
X is a halogen atom or an alkyl group of 1 to 20 carbon atoms
(b) an aluminoxane and/or a boron compound as a cocatalyst,
when the cocatalyst is aluminoxane, the molar ratio of the central metal M to aluminum atom of aluminoxane is 1:50˜1:5,000; when the cocatalyst is boron compound, the molar ratio of the central metal M to boron atom of the boron compound is 1:0.01˜1:100; and when the cocatalyst is a mixture of aluminoxane and boron compound, the molar ratio of the central metal M: boron atom of the boron compound: aluminum atom of the aluminoxane is 1:0.5˜5:5˜500.
2. The method of producing an ethylene homopolymer according to claim 1 , wherein, at the time of polymerizing ethylene monomers, a pressure of ethylene monomers in a reactor is 5˜150 atm.
3. A method of producing an ethylene-olefin copolymer at a polymerization temperature of 60˜250° C. using the transition metal system comprising;
(a) a transition metal catalyst system;
represented by Formula 1 below, which includes a cyclopentadiene derivative and one or more anionic ligands having an aryl group substituted with an aryl derivative at an ortho-position thereof around a transition metal, the ligands not being crosslinked to each other:
wherein M is titanium;
Cp is cyclopentadienyl or pentamethylcyclopentadienyl group which forms a η 5 -bond with the central metal M;
D is N—R 1 , in which R 1 is a hydrogen atom or an aryl group of 6 to 30 carbon atoms:
R 2 , R 3 , and R 4 are a hydrogen atom;
R 5 , R 6 , R 7 , R 8 and R 9 are each independently a hydrogen atom, a linear or nonlinear alkyl group of 1 to 20 carbon atoms, an aryl group of 6 to 30 carbon atoms, or an alkoxy group selected from a methoxy group, ethoxy group, isopropoxy group, and tert-butoxy group, and R 5 , R 6 , R 7 , R 8 and R 9 may be arbitrarily bonded with each other to form rings;
E is C—R 10 , in which R 10 ° is a hydrogen atom;
n is an integer of 1 or 2; and
X is a halogen atom or an alkyl group of 1 to 20 carbon atoms;
(b) an aluminoxane and/or a boron compound as a cocatalyst,
when the cocatalyst is aluminoxane, the molar ratio of the central metal M to aluminum atom of aluminoxane is 1:50˜1:5,000; when the cocatalyst is boron compound, the molar ratio of the central metal M to boron atom of the boron compound is 1:0.01˜1:100; and when the cocatalyst is a mixture of aluminoxane and boron compound, the molar ratio of the central metal M: boron atom of the boron compound: aluminum atom of the aluminoxane is 1:0.5˜5:5˜500.
4. The method of producing an ethylene-olefin copolymer according to claim 3 , wherein an olefin co-monomer which is used to conduct polymerization along with ethylene is one or more selected from the group consisting of propylene, 1-butene, 1-hexene, 1-octene, 1-decene, and vinylcyclohexane, and an amount of ethylene in the copolymer is 60 wt % or more.
5. The method of producing an ethylene-olefin copolymer according to claim 3 , wherein a pressure of ethylene monomers in a reactor is 5˜150 atm.
6. The method of producing an ethylene homopolymer according to claim 1 , wherein the cocatalyst is methyl aluminoxane.
7. The method of producing an ethylene homopolymer according to claim 1 , wherein the boron compound is selected from the group consisting of N,N-dimethylanilinium tetrakispentafluorophenylborate and triphenylmethylinium tetrakispentafluorophenylborate.
8. The method of producing an ethylene homopolymer according to claim 1 , wherein the organic alkyl aluminum is triethyl aluminum or triisobutyl aluminum.
9. The method of producing an ethylene-olefin copolymer according to claim 3 , wherein the cocatalyst is methyl aluminoxane.
10. The method of producing an ethylene-olefin copolymer according to claim 3 , wherein the boron compound is selected from the group consisting of N,N-dimethylanilinium tetrakispentafluorophenylborate and triphenylmethylinium tetrakispentafluorophenylborate.
11. The method of producing an ethylene-olefin copolymer according to claim 3 , wherein the organic alkyl aluminum is triethyl aluminum or triisobutyl aluminum.