摘要:
Method of determining the composition of polymer mixtures comprising defined polymer components of differing mean molar masses Mn, which comprises the steps (a) recording of at least one 1H-NMR relaxation curve of the polymer mixture and (b) calculating the proportions of the polymer components by matching the measured relaxation curve with the relaxation curves of the individual polymer components. In this way, the composition of polymer mixtures can be determined quickly and simply. Furthermore, process integration for regulating the polymerization is possible.
摘要:
Method of determining the composition of polymer mixtures comprising defined polymer components of differing mean molar masses Mn, which comprises the steps (a) recording of at least one 1H-NMR relaxation curve of the polymer mixture and (b) calculating the proportions of the polymer components by matching the measured relaxation curve with the relaxation curves of the individual polymer components. In this way, the composition of polymer mixtures can be determined quickly and simply. Furthermore, process integration for regulating the polymerization is possible.
摘要:
The invention relates to a process for preparing a catalyst for the polymerization of olefins, which comprises: a) preparation of a finely divided silica xerogel, b) loading of the xerogel with chromium from a solution of chromium trioxide or a chromium compound which is converted into chromium trioxide under the conditions of step c), and c) activation of the resulting product at from 400 to 1100° C. in a water-free gas stream comprising oxygen in a concentration of above 10% by volume, wherein a fluoride doping with a fluorinating agent is carried out in step b) or in step c). Furthermore, the invention relates to a catalyst for the polymerization of olefins which is obtainable by the process of the invention and to a process for the polymerization of olefins in which an olefin or an olefin mixture is polymerized in the presence of a catalyst according to the invention.
摘要:
The invention relates to a process for preparing a catalyst for the polymerization of olefins, which comprises: a) preparation of a finely divided silica xerogel, b) loading of the xerogel with chromium from a solution of chromium trioxide or a chromium compound which is converted into chromium trioxide under the conditions of step c), and c) activation of the resulting product at from 400 to 1100° C. in a water-free gas stream comprising oxygen in a concentration of above 10% by volume, wherein a fluoride doping with a fluorinating agent is carried out in step b) or in step c). Furthermore, the invention relates to a catalyst for the polymerization of olefins which is obtainable by the process of the invention and to a process for the polymerization of olefins in which an olefin or an olefin mixture is polymerized in the presence of a catalyst according to the invention.
摘要:
The inner wall of a solids reactor for carrying out reactions in the gas phase is coated with an antistatic layer having a thickness of 0.1-800 &mgr;m and consisting essentially of a poly-&agr;-olefin and a nonvolatile antistatic agent.
摘要:
The invention relates to a process for preparing a supported catalyst, in particular for the polymerization and/or copolymerization of olefins, which comprises: a) preparing a hydrogel; b) milling the hydrogel to give a finely particulate hydrogel; c) producing a slurry based on the finely particulate hydrogel; d) drying the slurry comprising the finely particulate hydrogel to give the support for catalysts; e) producing the supported catalyst by applying at least one transition metal and/or at least one transition metal compound to the support for catalysts and, if appropriate, activating the applied metal and/or compound, wherein a finely particulate hydrogel in which at least 5% by volume of the particles, based on the total volume of the particles, have a particle size in the range from >0 μm to ≦3 μm; and/or at least 40% by volume of the particles, based on the total volume of the particles, have a particle size in the range from >0 μm to ≦12 μm, and/or at least 75% by volume of the particles, based on the total volume of the particles, have a particle size in the range from >0 μm to ≦35 μm, is produced in step b) and a support which can be prepared as set forth in steps a) to d) is used to produce catalysts in step e).
摘要:
A hollow plastic article is described, with at least one opening and with a structure which has one or more layers, the hollow plastic article comprising at least one layer made from a polyolefin which was prepared using a fluorine-modified chromium catalyst. The use of hollow plastic articles of the invention as plastic fuel containers, gasoline canisters, plastic tanks, or plastic bottles or the like is also described.
摘要:
In a method of selecting polymerization catalysts, in particular Phillips catalysts for the polymerization of olefins, from a multiplicity of catalysts on the basis of their catalytic properties, a multiplicity of catalyst precursors or catalyst supports are converted in parallel into polymerization catalysts in a pretreatment step in an array of reactors, where the pretreatment comprises at least one thermal treatment step at from 250 to 1200° C. Furthermore, at least one starting material is converted with the aid of the respective polymerization catalysts under prescribed polymerization conditions into at least one polymer product in a polymerization step and, finally, analysis of the polymer product or products is carried out to determine its composition and/or chosen properties. This makes it possible to carry out a thermal pretreatment of polymerization catalysts quickly under defined conditions which can be varied.
摘要:
Polymers of ethylene are obtainable by polymerization of ethylene and, if desired, further comonomers in the presence of a catalyst system comprising as active constituents I) a Phillips catalyst, II) a solid which is different from I) and comprises a component which is derived from the metallocene complexes of the formula (A) in which the substituents and indices have the following meanings: R1 to R10 are hydrogen, C1-C10-alkyl, 5-to 7-membered cycloalkyl which may in turn bear C1-C6-alkyl groups as substituents, C6-C15-aryl or aryalkyl, where two adjacent radicals may also together form a cyclic group having from 4 to 15 carbon atoms, or Si(R11)3, where R11 is C1-C10-alkyl, C6-C15-aryl or C3-C10-cycloalkyl, or the radicals R4 and R9 together form a group —[Y(R12R13)]m—, where Y is silicon, germanium, tin or carbon, and R12, R13 are hydrogen C1-C10-alky, C3-C10-cycloalyl or C6-C15-aryl, M is a metal of transition groups IV to VIII or a metal of the lanthanide series, Z1, Z2 are fluorine, chlorine, bromine, iodine, hydrogen, C1-C20-alkyl or aryl, —OR14, —OOCR14, where R14 is hydrogen or C1-C20-alkyl; R15 is C1-C20-alkyl; m is 1,2,3 or 4; n is 0, or 2; r is 0, 1 or 2; the sum n+r is likewise 0, 1 or 2, and, if desired, III) an organometallic component selected from groups IA, IIA, IIB and IIIA of the Periodic Table of the Elements.
摘要:
In a method of selecting polymerization catalysts, in particular Phillips catalysts for the polymerization of olefins, from a multiplicity of catalysts on the basis of their catalytic properties, a multiplicity of catalyst precursors or catalyst supports are converted in parallel into polymerization catalysts in a pretreatment step in an array of reactors, where the pretreatment comprises at least one thermal treatment step at from 250 to 1200° C. Furthermore, at least one starting material is converted with the aid of the respective polymerization catalysts under prescribed polymerization conditions into at least one polymer product in a polymerization step and, finally, analysis of the polymer product or products is carried out to determine its composition and/or chosen properties. This makes it possible to carry out a thermal pretreatment of polymerization catalysts quickly under defined conditions which can be varied.