摘要:
A process for the preparation of homo or copolymers of ethylene, said process comprising: i) in a first polymerisation stage, continuously polymerising ethylene and optionally at least one C3-10 α-olefin, the reaction mixture further comprising a diluent and a metallocene catalyst having at least one optionally substituted indenyl ligand, said first polymerisation stage being effected essentially in the absence of hydrogen and with an ethylene concentration of 0.005 to 25 % mol relative to said diluent, preferably 0.005 to 4 % mol to a yield a polymer slurry; ii) in a second polymerisation stage continuously polymerising the polymer slurry resulting from said first polymerisation stage with the addition of further ethylene and optionally at least one C3-10 α-olefin and optionally hydrogen; wherein the first and second polymerisation stages are so effected that the ratio of the weight of polymer produced in the first polymerisation stage to the weight of polymer produced in the second polymerisation stage is 0.1:99.9 to 20:80, that the polymer produced in the first polymerisation stage has long chain branches and that essentially no further long chain branches are formed during the second polymerisation stage.
摘要:
A process for the preparation of homo or copolymers of ethylene, said process comprising: i) in a first polymerisation stage, continuously polymerising ethylene and optionally at least one C3-10 α-olefin, the reaction mixture further comprising a diluent and a metallocene catalyst having at least one optionally substituted indenyl ligand, said first polymerisation stage being effected essentially in the absence of hydrogen and with an ethylene concentration of 0.005 to 25 % mol relative to said diluent, preferably 0.005 to 4 % mol to a yield a polymer slurry; ii) in a second polymerisation stage continuously polymerising the polymer slurry resulting from said first polymerisation stage with the addition of further ethylene and optionally at least one C3-10 α-olefin and optionally hydrogen; wherein the first and second polymerisation stages are so effected that the ratio of the weight of polymer produced in the first polymerisation stage to the weight of polymer produced in the second polymerisation stage is 0.1:99.9 to 20:80, that the polymer produced in the first polymerisation stage has long chain branches and that essentially no further long chain branches are formed during the second polymerisation stage.
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:
A process for the preparation of homo or copolymers of ethylene, said process comprising: i) in a first polymerisation stage, continuously polymerising ethylene and optionally at least one C3-10 α-olefin, the reaction mixture further comprising a diluent and a metallocene catalyst having at least one optionally substituted indenyl ligand, said first polymerisation stage being effected essentially in the absence of hydrogen and with an ethylene concentration of 0.005 to 25 % mol relative to said diluent, preferably 0.005 to 4 % mol to a yield a polymer slurry; ii) in a second polymerisation stage continuously polymerising the polymer slurry resulting from said first polymerisation stage with the addition of further ethylene and optionally at least one C3-10 α-olefin and optionally hydrogen; wherein the first and second polymerisation stages are so effected that the ratio of the weight of polymer produced in the first polymerisation stage to the weight of polymer produced in the second polymerisation stage is 0.1:99.9 to 20:80, that the polymer produced in the first polymerisation stage has long chain branches and that essentially no further long chain branches are formed during the second polymerisation stage.
摘要:
A process for the preparation of a heat sealable film comprising a core layer and a sealing layer, said process comprising attaching said core layer to said sealing layer, said sealing layer comprising an ethylene copolymer composition in which: (1) there are two distinct maxima in the TREF fractogram of the ethylene copolymer composition; (2) at lest 10 %, of the ethylene copolymer composition elutes in TREF at a temperature of less than 50 °C; (3) at least 25 %, of the ethylene copolymer composition elutes in TREF at a temperature of higher than 75 °C; (4) none of the ethylene copolymer composition elutes in TREF at a temperature of higher than 100 °C; (5) the ethylene copolymer composition comprises two components, one of which is of relatively high comonomer content and high molecular weight, the other of which is of relatively low comonomer content and low molecular weight, both components being prepared by polymerisation of ethylene with a C3-20 alpha-olefin in the present of a single site catalyst; (6) the ethylene copolymer composition has a density of between 905 and 930 kg/m3, and an MFR¿2? between 0.3 and 4.0 g/10 min.
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.
摘要:
A process for the preparation of a heat sealable film comprising a core layer and a sealing layer, said process comprising attaching said core layer to said sealing layer, said sealing layer comprising an ethylene copolymer composition in which: (1) there are two distinct maxima in the TREF fractogram of the ethylene copolymer composition; (2) at lest 10 %, of the ethylene copolymer composition elutes in TREF at a temperature of less than 50 °C; (3) at least 25 %, of the ethylene copolymer composition elutes in TREF at a temperature of higher than 75 °C; (4) none of the ethylene copolymer composition elutes in TREF at a temperature of higher than 100 °C; (5) the ethylene copolymer composition comprises two components, one of which is of relatively high comonomer content and high molecular weight, the other of which is of relatively low comonomer content and low molecular weight, both components being prepared by polymerisation of ethylene with a C3-20 alpha-olefin in the present of a single site catalyst; (6) the ethylene copolymer composition has a density of between 905 and 930 kg/m3, and an MFR¿2? between 0.3 and 4.0 g/10 min.
摘要:
A polymerisation method with improved productivity, using a co-ordination catalyst, whereby electromagnetic radiation is applied during the polymerisation. The activity of the co-ordination catalyst is greatly enhanced by the irradiation with light.