摘要:
Supported olefin polymerization catalyst compositions prepared by contacting, previous to or immediately before the beginning of the olefin polymerization, a support comprising a porous carrier, optionally with a) an organometallic compound of the general formula (1): R1MXv-1, wherein each R is the same or different and is a C1-C10 alkyl group; M is a metal of Group 1, 2, 12 or 13 of the Periodic Table; each X is the same or different and one of a halogen atom, a hydrogen atom, a hydroxyl radical or a C1-C8 hydrocarbyloxy group; 1 is 1, 2 or 3; v is the oxidation number of the metal M, and with a complex solution of at least b) a metallocene of the general formula (2): (CpY)mM'X'nZo, wherein each CpY is the same or different and is one of a mono- or polysubstituted, fused or non-fused, homo- or heterocyclic cyclopentadienyl, indenyl, tetrahydroindenyl, fluorenyl, or octahydrofluorenyl ligand, which ligand is substituted at its cyclopentadienyl ring with at least one substituent Y which is one of a -OR', -SR', -NR'2, -C(H or R')=, or -PR'2 radical, each R' being the same or different and being a tri-C1-C8 hydrocarbyl silyl group or a tri-C1-C8 hydrocarbyloxy silyl group; M' is a transition metal of Group 4 of the Periodic Table and bound to the ligand CpY at least in an θ5 bonding mode; each X' is the same or different and is one of a hydrogen atom, a halogen atom, a C1-C8 hydrocarbyl group, a C1-C8 hydrocarbylheteroatom group or a tri-C1-C8 hydrocarbylsilyl group or two X' form a ring with each other; Z is a bridge atom or group between two CpY ligands or one CpY ligand and the transition metal M'; m is 1 or 2; o is 0 or 1; and n is 4-m if Z is a bridge between two CpY ligands or n is 4-m-o if Z is a bridge between one CpY ligand and the transition metal M', and c) an alumoxane of general formula (3), wherein each R'' and each R''' is the same or different and is a C2-C10 alkyl group; and p is an integer between 1 and 40, and recovering said supported olefin polymerization catalyst composition.
摘要:
Process for polymerizing or copolymerizing ethylene for manufacturing ethylene polymers or copolymers having a controlled particle size and morphology. Ethylene is polymerized or copolymerized under ethylene polymerizing conditions in the presence of a supported metallocene catalyst, where the average particle size of the catalyst particles is selected within the range of 14-40 νm and the residence time at the polymerization is selected so as to achieve a polymer where average particle size is between 0.3-0.5 mm and the proportion of fractions between 0.1-0.6 is at least 80 %.
摘要:
This invention concerns process for producing polyethylene compositions, films prepared thereof and process for the preparation of the films. The process comprises subjecting ethylene, optionally hydrogen and comonomers to polymerization or copolymerization reactions in a multistage polymerization. At least one polymerization stage is conducted essentially in the absence of hydrogen. The polymerization reactions are carried out in the presence of a single-site catalyst capable of forming a composition comprising a low molecular weight component with MFR2 of at least 10 g/10 min and a density higher than the density of the composition and a high molecular weight component. The melt flow rate of the composition is in the range MFR2 = 0.1 - 5.0 g/10 min and the density of the composition is 915 - 960 kg/m3. The invention makes it possible to produce polyethylene compositions for manufacturing films with a good balance between optical and mechanical properties.