摘要:
A process for polymerizing one or more alpha-olefins of formula CH2═CHT wherein T is a hydrogen atom or a C1-C20 alkyl radical comprising the following steps: a) contacting in a continuous way one or more of said alpha olefins with a metallocene based catalyst system in a loop reactor, wherein: (i) the reaction is carried out in a liquid medium; (ii) the average residence time of the metallocene-based catalyst system is not more than 30 minutes; (iii) the temperature of the loop ranges from 25° to 70° C.; in to obtain a polymerization degree ranging from 60 to 500 g per gram of catalyst system; b) feeding in continuous the prepolymerized metallocene-based catalyst system obtained in step a) into a polymerization reactor C) polymerizing one or more alpha-olefins, the same or different from the alpha olefins used in step a), in the presence of said prepolymerized metallocene-based catalyst system.
摘要:
A process for polymerizing one or more alpha-olefins of formula CH2═CHT wherein T is a hydrogen atom or a C1–C20 alkyl radical comprising the following steps: a) contacting in a continuous way one or more of said alpha olefins with a metallocene based catalyst system in a loop reactor, wherein: (i) the reaction is carried out in a liquid medium; (ii) the average residence time of the metallocene-based catalyst system is not more than 30 minutes; (iii) the temperature of the loop ranges from 25° to 70° C.; in order to obtain a polymerization degree ranging from 60 to 500 g per gram of catalyst system; b) feeding in continuous the prepolymerized metallocene-based catalyst system obtained in step a) into a polymerization reactor C) polymerizing one or more alpha-olefins, the same or different from the alpha olefins used in step a), in the presence of said prepolymerized metallocene-based catalyst system.
摘要:
Catalyst system for olefin polymerization comprising A) at least one calcined hydrotalcite, B) at least one organic transition metal compound, C) optionally one or more cation-forming compounds and D) at least one organic magnesium compound.
摘要:
A catalyst solid comprising: A) support particles having a mean particle diameter d50 of from 5 to 200 μm and a specific surface area of from 30 to 1 000 m2/g and obtainable by agglomeration of primary particles of a pyrogenic silica having a mean particle diameter dm of from 1 to 50 nm, and B) at least one organic transition metal compound, can be used for the polymerization or copolymerization of olefins.
摘要:
A process for the polymerization of olefins, in particular a process for the copolymerization of propylene with further olefins, is carried out in the presence of highly active catalyst systems comprising specifically selected metallocenes, in particular ones which bear different substituents in position 2 and position 4 on an indenyl ligand. Novel polypropylene copolymers can be obtained by this process.
摘要:
A process for the polymerization of olefins, in particular a process for the copolymerization of propylene with further olefins, is carried out in the presence of highly active catalyst systems comprising specifically selected metallocenes, in particular ones which bear different substituents in position 2 and position 4 on an indenyl ligand. Novel polypropylene copolymers can be obtained by this process.
摘要:
Catalyst solid for olefin polymerization comprising A) at least one calcined hydrotalcite and B) at least one organic transition metal compound, and also a catalyst system comprising the catalyst solid, the use of the catalyst solid for the polymerization or copolymerization of olefins and a process for preparing polyolefins by polymerization or copolymerization of olefins in the presence of the catalyst solid.
摘要:
A process for the polymerization of olefins, in particular a process for the copolymerization of propylene with further olefins, is carried out in the presence of highly active catalyst systems comprising specifically selected metallocenes, in particular ones which bear different substituents in position 2 position 4 on an indenyl ligand. Novel polypropylene copolymers can be obtained by this process.
摘要:
Disclosed are compounds of the following core structure, and their use as polymerization catalysts: wherein M1 is a group lVb transition metal, R5 is a substituted aryl group, and Ra forms a heteroatom-containing ring fused to the cyclopentadienyl ring.
摘要:
The invention refers to a process for preparing a supported catalyst system for the polymerization of olefins comprising at least one active catalyst component on a support, the process comprisingA) impregnating a dry porous support component with a mixture comprising at least one precatalyst, at least one cocatalyst, and a first solvent, such that the total volume of the mixture is from 0.8 to 2.0 times the total pore volume of the support component, and B) thereafter, adding a second solvent in an amount of more than 1.5 times the total pore volume of the support component. The invention refers further to a catalyst system made by this process and the use of this catalyst system for polymerization or copolymerization of olefins.