Abstract:
The sagging problem in the manufacture of thick walled pipes is solved using a polyethylene molding composition having a multimodal molecular mass distribution and comprising from 45 to 55% by weight of a first low molecular weight ethylene homopolymer A, from 20 to 40% by weight of a second high molecular weight copolymer B comprising ethylene and another olefin having from 4 to 8 carbon atoms and from 15 to 30% by weight of a third ultrahigh molecular weight ethylene copolymer C prepared in the presence of a Ziegler catalyst in a three-stage polymerization process comprising additionally an organic polyoxy compound or an organic polyhydroxy compound in an amount of from 0.01 to 0.5% by weight.
Abstract:
The invention relates to a polyethylene molding composition which has a multimodal molecular mass distribution and comprises a low molecular weight ethylene homopolymer A, a high molecular weight ethylene copolymer B and an ultrahigh molecular weight ethylene copolymer C. The molding composition has a density at a temperature of 23° C. in the range from 0.940 to 0.957 g/cm3, an MFR (190° C./2.16 kg) in the range from 0.5 to 4 dg/min and a viscosity number VN3 of the mixture of ethylene homopolymer A, copolymer B and ethylene copolymer C, measured in accordance with ISO/R 1191 in decalin at a temperature of 135° C., in the range from 150 to 300 cm3/g. The invention further relates to the use of such a molding composition for producing injection-molded finished parts, and to finished parts produced by injection molding.
Abstract:
Molding composition comprising polyethylene and having a density in the range from 0.915 to 0.955 g/cm, an MI in the range from 0 to 3.5 g/10 min, an MFR in the range from 5 to 50, a polydispersity Mw/Mn in the range from 5 to 20, and a z-average moiar mass Mz of less than 1 million g/mol, a process for preparing such a composition, a catalyst suitable for the preparation of the same, as well as films comprising this molding composition.
Abstract:
A polyethylene molding composition having a multimodal molecular mass distribution and comprising from 45 to 55% by weight of a low molecular weight ethylene homopolymer A, from 20 to 40% by weight of a high molecular weight copolymer B comprising ethylene and another olefin having from 4 to 8 carbon atoms and from 15 to 30% by weight of an ultrahigh molecular weight ethylene copolymer C can be prepared in the presence of a Ziegler catalyst in a three-stage process and is highly suitable for producing pipes having excellent mechanical properties.
Abstract:
Ethylene is polymerized using a Ziegler catalyst system consisting of (1) a titanium catalyst component and (2) an aluminum catalyst component, the component (1) used being the product (VI) which is obtained by a method in which (1.1) first (1.1.1) a carrier (I) and (1.1.2) a solution (II) of (IIa) a solvent, (IIb) a titanium trichloride and (IIc) magnesium chloride are combined with formation of a dispersion (III) and the latter is evaporated down with formation of an intermediate (IV), and (1.2) then (1.2.2) the intermediate (IV) obtained from (1.1), and (1.2.2) an aluminum component (V) consisting of (1.2.2.1) a complex of a certain oxacycloalkane and a certain aluminum compound and (1.2.2.2) if necessary, a certain free aluminum compound are combined, the resulting product (VI) being the catalyst component (1). In this process, a component (1) is employed which has been prepared using, in (1.1) under (1.1.2), a solution (II) which (i) contains a ketone as (IIa) and (ii) additionally contains (IId) a certain low molecular weight polymeric compound.
Abstract:
A spatially movable device 1 is disclosed which is provided with actuators 7a-7f in such a manner that the system consists of a manual unit 2 with a process control unit 5 and a input unit 6 as well as a monitor 8. The manual unit 2 is operated in such a manner that the control elements 3a-3f are controlled by an operator's hand which through individual fingers controls the selection of various position parameters. A slider 4 is provided which controls the direction and speed of the selected parameter change with the slider being accessible to the thumb of the operator in order to provide complete operation by one hand and simultaneously setting and controlling the parameter values which are displayed on the monitor 8.
Abstract:
A process for coating the exterior surfaces of a pipeline with a polymer that is cross-linkable under exposure to water, including a) coating the exterior surface of the pipeline with at least one polymer that is cross-linkable under exposure to water, where the employed cross-linkable polymer includes alkoxy silane grafted HDPE; and b) cross-linking of the cross-linkable polymer by exposure to water at elevated temperatures so as to form a cross-linked polymer layer having a degree of cross-linking of from 30% to 80% is reached.
Abstract:
A multilayered composite structure comprises at least one layer (A) consisting of an ethylene homopolymer or copolymer, at least one layer (B) comprising a barrier material and at least one layer (C) comprising an adhesion promoter material serving to improve the adhesion between these layers, wherein the adhesion promoter material comprises an adhesive polymer composition comprising a) 20 to 95% (w/w) of an ethylene homo- or copolymer which is a copolymer of ethylene with C3-C20-alkene, and b) 5 to 80% (w/w) of a polar copolymer of ethylene with at least one comonomer which comonomer is selected from the group consisting of an acrylate and acrylic acid. The composite structure can be used for fuel containers, especially fuel tanks in automotive vehicles.
Abstract:
The invention concerns a coating and a process for the coating of exterior surfaces. More particularly, the invention concerns a process for the coating of exterior surfaces of pipelines with polymer cross-linkable under exposure to water.