Patent ID: 8674026
Filing Date: 2014-03-18
Classification: C08F,Y10S,Y10T

Abstract:
1. An ethylene copolymer resin having trimodal or higher molecular weight distribution, which has an ethylene content of more than 60 wt % and a density of 0.900 to 0.950 g/cm 3 , the ethylene copolymer resin is prepared by a multistage solution polymerization using at least three polymerization reactors, the multistage solution polymerization comprising the following steps: (a) polymerizing ethylene with at least one C4-C10 α-olefin in a first reactor using a metallocene catalyst represented by the following formula 1, which comprises a cyclopentadienyl group containing ligand around a transition metal and aryloxide ligand or ligands substituted with aryl derivatives at the ortho-positions, the ligands not being bridged, thus producing a first copolymer solution in which a first polymer fraction has a density of 0.860-0.920 g/cm (b) passing the first copolymer solution through a second reactor, which contains the same metallocene catalyst as used in step (a), ethylene and at least one C4-C10 α-olefin, at a temperature higher than the reaction temperature of step (a), thus producing a second copolymer solution in which a second polymer fraction has a density of 0.900-0.940 g/cm (c) passing the second copolymer solution through a third reactor, which contains a Ziegler-Natta catalyst different from the catalyst used in step (b), ethylene and at least one C4-C10 α-olefin, at a temperature higher than the reaction temperature of step (b), thus producing a third copolymer solution containing a third polymer fraction: wherein M is a group-IV transition metal in the periodic table; Cp is cyclopentadienyl or a derivative thereof, which forms an η5-bond with the central metal; R1, R2, R3, R4, R5, R6, R7, R8 and R9 on the aryloxide ligands are each independently a hydrogen atom, a halogen atom, a C1-C20 linear or nonlinear alkyl group optionally substituted with at least one halogen atom, a silyl group containing a C1-C20 linear or nonlinear alkyl group optionally substituted with at least one halogen atom, a C6-C30 aryl group optionally substituted with at least one halogen atom, an C7-C30 arylalkyl group optionally substituted with at least one halogen atom, an alkoxy group having a C1-C20 linear or nonlinear alkyl group optionally substituted with at least one halogen atom, a siloxy group substituted with C3-C20 alkyl or C6-C20 aryl, an amido or phosphido group having a C1-C20 hydrocarbon group, or a mercapto or nitro group substituted with C1-C20 alkyl, wherein these substituents are optionally bound to each other to form a ring; and X is selected from the group consisting of a halogen atom, a C1-C20 alkyl group other than a Cp derivative, a C7-C30 arylalkyl group, an alkoxy group having a C1-C20 alkyl group, a siloxy group substituted with C3-C20 alkyl, and an amido group having a C1-C20 hydrocarbon group; and n is an integer between 1 and 3, wherein the contents of the first polymer fraction, the second polymer fraction and the third polymer fraction in the ethylene copolymer resin are in the range of 2 to 20 wt %, 5 to 78 wt % and 20 to 75 wt %, respectively, based on the ethylene copolymer resin.