Abstract: Process for the preparation of oxymethylene polymers and apparatus suitable for this purpose A process and an apparatus for the preparation of oxymethylene polymers is described. The process encompasses the polymerization of a monomer that forms oxymethylene groups, if appropriate in the presence of a cyclic acetal, together with an acetal of formaldehyde and with an initiator for cationic polymerization, preferably in a gas-tight kneader or extruder. The temperature profile of the polymerization here is designed in such a way that the polymerization mixture, which is initially heterogeneous by virtue of precipitating polymer, is converted to a homogeneous phase at the end of the polymerization. The homogeneous phase in which the polymer is present in liquid form is stabilized via addition of deactivators. After removal of volatile constituents, oxymethylene polymers are obtained with high thermal stability and with good mechanical properties.

Abstract: Molding materials and the moldings produced therefrom, containing a) polyoxymethylene in which at least 50% of the terminal groups are hydroxyl groups, which has a melt volume rate MVR of less than 20 cm3/10 minutes, measured according to ISO 1133 at 190° C. and 2.16 kg, and whose proportion of low molecular weight constituents having low molecular weights below 10 000 dalton is less than 15% by weight, based on the total mass of the polyoxymethylene, and b) a thermoplastic elastomer, are described. The moldings produced from these molding materials are distinguished by a very high notch impact strength.

Abstract: The present invention relates to a method for the manufacturing of a container or parts of a container for fuel or compressed gases by extrusion blow molding and container or parts of container for fuel or compressed gases made thereof.

Abstract: Oxymethylene polymers having a bimodal distribution or having a distribution of higher modality and having a targeted content of a low molecular weight fraction of from 1 to 5 percent by mass are described. Moldings of these polymers are distinguished by high low-temperature notched impact strength associated with a high modulus of elasticity.

Abstract: Composites are described, comprising polyacetal and at least one thermoplastic polyamide elastomer formed by a polyacetal molding which has been partially or completely coated with the thermoplastic polyamide elastomer or onto which one or more moldings composed of the thermoplastic polyamide elastomer have been directly molded. The composites are characterized in that the polyacetal and the thermoplastic polyamide elastomer have been bonded adhesively or cohesively to one another via injection of the polyamide elastomer onto the polyacetal molding, and in that the tensile bond strength between the polyacetal and the thermoplastic polyamide elastomer is at least 0.5 N/mm2. The composites may be used as connectors, as functional components with integrated sealing properties and/or with integrated damping properties, or else as non-slip and easy-grip elements.

Abstract: The present invention relates to a molding composition, a process for the manufacturing of said molding composition, molded parts obtainable therefrom as well as the use of the molding composition for the manufacturing of molded parts used in the automotive industry, for housings, latches, window winding systems, wiper systems, sun roof systems, seat adjustments, levers, gears, claws, pivot housing or wiper arms.

Abstract: An initiator for cationic polymerization comprises a salt of a protic acid as well as a protic acid. The molar ratio of protic acid to salt is in the range from 1:0.01 to 1:2000. The initiator is used for example for cationic homo- or copolymerization of trioxane, and permits stable and flexible operation of the polymerization.

Abstract: Oxymethylene polymers having a bimodal distribution or having a distribution of higher modality and having a targeted content of a low molecular weight fraction of from 1 to 5 percent by mass are described. Moldings of these polymers are distinguished by high low-temperature notched impact strength associated with a high modulus of elasticity.

Abstract: Oxymethylene copolymers having a high proportion of terminal alkyl ether groups and having terminal hydroxyalkylene groups are described. These polymers are distinguished by high thermal stability and high hot water resistance.

Abstract: A process for forming shaped three-dimensional products is described made from a composition containing at least one filler and an aromatic liquid crystal polymer. In one embodiment, the process includes forming a substrate such as a film, a sheet or a tube, through an extrusion process. Once the substrate is formed, the substrate is then heated and fed to a shaping process. The shaping process may comprise a thermal forming process or a blow molding process. In order to form the three-dimensional products, the aromatic liquid crystal polymer has a high heat of crystallization, a high melt temperature and/or a high melt viscosity.

Abstract: The invention relates to a modular container for the preparation of foods, in particular baked goods, by cooking, comprising a self-supporting base plate (1) having an extension in one plane, and limiting elements (4, 5, 6) which project from the plane and which are detachably connected to the base plate (1).

Abstract: The present invention relates to a polyoxymethylene molding composition comprising (A) 0.1-5.0% by weight of colorant, (B) 0.01-0.5% by weight of a nitrogen-containing stabilizer, (C) 0.05-1% by weight of an ester of a polyhydric alcohol and at least one fatty acid, and (D) 0.001-0.5% by weight of a metal salt of a fatty acid, and (I) polyoxymethylene polymer and, where appropriate, up to 40% by weight of other conventional additives, and variants of this constitution in advantageous versions. In the case of these polyoxymethylene molding compositions the selection of the colorants is no longer restricted to conventional colorants suitable particularly for POM. The products produced therewith are particularly stable during processing and feature low formaldehyde emission, defect-free surfaces, and high color fastness.

Abstract: The present invention relates to a process of manufacturing high, very high, and ultra high molecular weight polymers comprising predominantly ethylene monomers. Ethylene is reacted in the presence of a catalyst system to produce a polymer having a viscosimetrically-determined molecular weight of at least 0.7×106 g/mol. The catalyst system generally includes a bridged metallocene catalyst compound, optionally with a co-catalyst. The catalyst is characterized by a zirconium dichloride central functionality and a dimethyl silandiyl bridge between five-membered rings of indenyl groups. Both rings of the metallocene compound are substituted at the 2-position with respect to the dimethyl silandiyl bridge with a C1-C20 carbonaceous group.

Abstract: Polyoxymethylene molding compositions, their use, and moldings produced therefrom A ground molding composition is described, comprising a) a compounded material composed of i) at least one polyoxymethylene homo- and/or copolymer, ii) at least one impact modifier, and iii) optionally other conventional additives, which b) has been milled to give a powder at least 90% by weight of whose particles have a grain size of <600 ?m and a median grain size (D50) of from 100 to 500 ?m. These molding compositions can be processed to give moldings, in particular via rotomolding.

Abstract: A process and an apparatus are described for preparation of oxymethylene polymers. This process encompasses polymerization, in a homogeneous phase, of a monomer which forms oxymethylene groups, as far as 90% of maximum conversion in the presence of an acetal of formaldehyde and of an initiator for cationic polymerization, followed by deactivation of the reaction mixture. The resultant oxymethylene polymers have alkyl ether end groups and are extremely stable.

Abstract: The present invention relates to a process for the preparation of oxymethylene polymers as well as oxymethylene polymers obtainable therefrom. The process includes polymerization of a monomer, which forms —CH2—O— units in the presence of an acetal of formaldehyde or a polyhydric alcohol and an initiator for cationic polymerization. The initiator may be a heteropoly acid or an acid salt thereof which is dissolved in an alkyl ester of a polybasic carboxylic acid.

Abstract: Compositions are described comprising a) polyoxymethylene, b) thermoplastic elastomer having active hydrogen atoms, c) polyoxymethylene which differs from component a) and contains active hydrogen atoms, d) reagent for covalent coupling of components b) and c), and e) if appropriate, another impact modifier, which differs from component b). The compositions feature improved toughness and can be used for production of moldings.

Abstract: The invention relates to a process for preparation of polymer blends comprising at least one polyoxymethylene and at least one thermoplastic elastomer, where the thermoplastic elastomer is micropelletized by a pelletizing process and the pellets obtained in a) are dispersed in the polyoxymethylene matrix via melting of the components and mixing of these at low shear forces, and also to the use of micropelletized thermoplastic elastomers for preparation of polyoxymethylenes with low formaldehyde emission.

Abstract: An initiator for cationic polymerization comprises a salt of a protic acid as well as a protic acid. The molar ratio of protic acid to salt is in the range from 1:0.01 to 1:2000. The initiator is used for example for cationic homo- or copolymerization of trioxane, and permits stable and flexible operation of the polymerization.

Abstract: Composite bodies, processes for making them, and their uses are disclosed, the composite bodies comprising a polyacetal portion and a modified thermoplastic vulcanizate portion bonded together, wherein the modified thermoplastic vulcanizate portion comprises a modified thermoplastic vulcanizate elastomer having a hardness of 30 to 90 Shore A and wherein the modified thermoplastic vulcanizate elastomer comprises: (a) 2 to 75% by weight of an at least partially crosslinked ethylene-propylene-diene rubber in from 1 to 50% by weight of a polyolefinic matrix further comprising 0.05 to 10% by weight of an ingredient selected from the group consisting of stabilizers, crosslinking aids, and mixtures thereof; (b) 1 to 30% by weight of a compatibilizer; and (c) 10 to 70% by weight of a non-olefinic thermoplastic material, all percentages by weight based on a total weight of the modified thermoplastic vulcanizate elastomer.