Abstract:
A PROCESS FOR THE PRODUCTION OF HOMOPOLYMERS OF ETHYLENE BY POLYMERIZATION OF ETHYLENE AT HIGH PRESSURE AND ELEVATED TEMPERATURE USING A MIXTURE OF A HYDROPERIOXIDE AND OXYGEN AS A POLYMERIZATION INITIATOR WITH OR WITHOUT A POLYMERIZATION REGULATOR. AN ESSENTIAL FEATURE OF THE PROCESS ACCORDING TO THE INVENTIONS IS THE USE OF HYDROPEROXIDES OF A SPECIALLY SELECTED CLASS OF COMPOUNDS.
Abstract:
Production of polyethylene by polymerizing ethylene at elevated temperatures and elevated pressure under the action of a polymerization initiator, consisting of oxygen and t-butyl hydroperoxide, and of a polymerization regulator. The process of the invention is characterized in that temperature ranging from 310* to 400*C are used and that the polymerization initiator consists of from 1 to 12 molar parts of oxygen and from 1 to 5 molar parts of t-butyl hydroperoxide per million molar parts of the ethylene being polymerized. The process of the invention is preferably carried out continuously in a tubular reactor. The process permits easy control of the reaction with high yields and provides products with high flexibility and elongation.
Abstract:
A PROCESS FOR POLYMERIZING ETHYLENE AT PRESSURES OF MORE THAN 1000 ATMOSPHERES AND AT TEMPERATURES OF FROM 150* TO 400*C. IN THE PRESENCE OF METHYL ISOBUTYL KETONE PEROXIDE. POLYETHYLENE HAVING A DENSITY OF FROM 0.924 TO 0.935 G/CCM. IS OBTAINED IN HIGHER YIELDS THAN IN CONVENTIONAL METHODS; IT IS USED FOR THE PRODUCTION OF TRANSPARENT FILM AND SHEETING.
Abstract:
A process for the production of ethylene copolymers containing hydroxyl groups which contain polymerized units of ethylene, an alkenol and if desired other monomers copolymerizable with ethylene, by copolymerization of a mixture of ethylene, alkenol and the other copolymerizable monomer(s), if any, at superatmospheric pressure and elevated temperature under the action of a free-radical polymerization initiator in the presence or absence of a polymerization regulator. 3-methyl-3-buten-1-ol is used as the alkenol. The process has the advantage that it is more easily carried out than comparable prior art methods and that it gives copolymers containing a relatively high proportion of polymerized units of alkenol.
Abstract:
PRODUCTION OF ETHYLENE HOMOPOLYMERS OR COPLYMERS BY POLYMERIZATION OF ETHYLENE OR OF MIXTURES OF MAJOR AMOUNTS OF ETHYLENE AND MINOR AMOUNTS OF OTHER MONOMERS AT SUPERATMOSPHERIC PRESSURE AND ELEVATED TEMPERATURE USING A POLYMERZATON INITIATOR. IT IS CHARACTERISTIC OF THE PROCESS ACCORDING TO THE INVENTIN THAT A 2-HYDROPEROXY-2-ISOPROPYLPHENYLPROPANE IS USED AS POLYMERIZATION INITIATOR.
Abstract:
Ethylenically unsaturated carboxylic acids and/or carboxylic anhydrides are grafted onto polyolefin blends by a process in which the polyolefin blend consists of from 5 to 49 parts by weight of an ethylene/propylene block copolymer having an ethylene content of less than or equal to 20% by weight and from 51 to 95 parts by weight of a homopolymer or copolymer of ethylene, and the resulting graft copolymer blends are used as adhesion promoters, in particular for polyethylene/ adhesion promoter/steel composites, and for the preparation of ionomers.
Abstract:
The novel catalyst for the preparation of high-molecular-weight homopolymers or copolymers of ethene is obtainable by (1) treating a silicon dioxide-based support with (2) chromium trioxide or a chromium compound which can be converted into chromium dioxide under the conditions of step (3), and then (3) heating the resultant intermediate in an oxygen-containing stream of gas, where the support (1) is a specific silicic acid xerogel obtainable by extracting a maximum of 30% of water from a silicic acid hydrogel by means of alkanols, alkanones or mixtures thereof, and subsequently drying, comminuting and fractionating the product.
Abstract:
In a new process for the preparation of a supported catalyst for the polymerisation of alpha -olefins, first a support gel (1) is prepared by introducing a sodium water glass or potassium water glass solution into a swirling stream of an aqueous mineral acid optionally containing aluminium ions longitudinally and tangentially to the stream, spraying the resultant silicic acid hydrosol in drop form into a gaseous medium, and allowing it to solidify to form a hydrogel, and freeing the resultant hydrogel, without prior ageing, from salts by washing and optionally from some of the water by extraction with alcohols and/or ketones, and then drying the hydrogel. This gives the support gel (1), which is ground and fractionated according to particle size. In a second process step, the support gel (1) is charged with chromium trioxide or with a chromium compound which can be converted into chromium trioxide, after which the resultant chromium-containing support gel (2) is heated at from 400 to 1100 DEG C for from 10 to 1000 minutes in an anhydrous gas stream containing oxygen in a concentration greater than 10% by volume. It is essential for the process according to the invention that the drying of the hydrogel to form the support gel (1) takes place in a high-speed drier within a maximum time of 300 seconds at an inlet temperature of from 200 to 600 DEG C. The supported catalyst prepared in this way gives homopolymers and copolymers of ethylene having excellent low-temperature toughness.
Abstract:
Homopolymers and copolymers of ethene are prepared using a Ziegler catalyst system comprising (1) a transition metal catalyst component, (2) an organoaluminum catalyst component and (3) an organohalogen catalyst component, by a method in which the transition metal catalyst component (1) employed is a solid-phase product (VI) obtained by (1.1) first combining (1.1.1) an inorganic oxidic substance ((I), as the carrier, with (1.1.2) a solution (II) consisting of (IIa) a certain oxahydrocarbon and (IIb) a mixture of (IIb1) a vanadium trichloride/alcohol complex, (IIb2) a titanium trihalide or titanium trihalide/alcohol complex and, if required, (IIb3) a zirconium tetrahalide to form a suspension (III), evaporating down this suspension to form a solid-phase intermediate (IV), and (1.2) then (1.2.1) combining the solid-phase intermediate (IV) obtained from (1.1) with (1.2.2) a solution of an organoaluminum compound (V) to form a suspension, the resulting suspended solid-phase product (VI) being the transition metal catalyst component (1).