Basf Aktiengesellschaft

Basf Se Corporation

Hans Wohlfromm

Johan Ter Maat

Martin Blömacher

Dieter Weinand

Martin Bloemacher

Arnd Thom

Hans-Josef Sterzel

Graham E McKee

Peter J Uggowitzer

Robert Loos

Andreas Kern

Jens Assmann

Markus Speidel

Werner Hesse

Franz-Dieter Martischius

Peter Trubenbach

Tsung-Chieh Cheng

Johan Herman Hendrik Ter Matt

Mario Nohe

Johan Herman Hendrik Ter Maat

Eva-Maria Langer

Manfred Schwarz

The invention relates to a process for the continuous thermal removal of binder from a metallic and/or ceramic shaped body which has been produced by injection molding, extrusion or pressing using a thermoplastic composition and comprises at least one polyoxymethylene homopolymer or copolymer as binder in a binder removal oven, which comprises the steps (a) removal of binder from the shaped body in a binder removal oven at a temperature which is from 5 to 20&#xb0; C. below, preferably from 10 to 15&#xb0; C. below, the temperature of a second temperature stage over a period of from 4 to 12 hours in a first temperature stage in an oxygen-comprising atmosphere, (b) removal of binder from the shaped body at a temperature in the range &#x3e;160 to 200&#xb0; C. over a period of from 4 to 12 hours in an oxygen-comprising atmosphere in a second temperature stage and (c) removal of binder from the shaped body at a temperature in the range from 200 to 600&#xb0; C. over a period of from 2 to 8 hours in a third temperature stage in an oxygen-comprising or neutral or reducing atmosphere, with the shaped bodies being transported through the binder removal oven during process steps (a) and (b).

Process for the continuous thermal removal of binder from a metallic and/or ceramic shaped body produced by injection molding, extrusion or pressing using a thermoplastic molding composition

Process for producing a shaped metallic body from a thermoplastic composition by injection molding or extrusion to form a shaped part, removal of the binder and sintering, wherein a thermoplastic composition composed of a metal powder and a polymer mixture B) and B) based on a polyoxymethylene homopolymer or copolymer B) is used as binder and to remove the binder

Process for producing components by powder injection molding

A process for producing a metallic or ceramic shaped body from a thermoplastic material comprising

Process for producing metallic or ceramic shaped bodies

The invention relates to binders for pulverulent metals, metal alloys or ceramics based on polyacetals, polyethers and polyesters, to thermoplastic compositions comprising these binders for the production of metallic or ceramic moldings, to the use thereof and to processes for production of moldings therefrom.

Binder and process for producing metallic or ceramic moldings in powder injection molding

The apparatus for the continuous catalytic removal of binder from metallic and/or ceramic shaped bodies produced by powder injection molding, which comprises a binder removal furnace through which the shaped bodies pass in a transport direction and are brought to a suitable process temperature, a feed facility for introduction of a process gas which is required for binder removal and comprises a reactant, at least one facility for the introduction of a protective gas into a reaction space of the binder removal furnace and a flare to burn the gaseous reaction products obtained in binder removal, wherein one or more devices which lead to a flow of the process gas directed transversely to the transport direction in the apparatus are present.

Device and method for continuously and catalytically removing binder, with improved flow conditions

A binder B for inorganic powders comprises a mixture of

Binding agent for inorganic material powders for producing metallic and ceramic moulded bodies

Hard sintered moldings having a nickel- and cobalt-free, nitrogen-containing steel as a binder of the hard phase, processes for the powder metallurgical production of these hard sintered moldings, in particular by powder injection molding, and powder injection molding materials for the production of these hard sintered moldings by powder injection molding.

Hard material sintered compact with a nickel- and cobalt-free, nitrogenous steel as binder of the hard phase

Metallic shaped bodies are produced from an injection-molding composition comprising at least one carbonyl metal powder and at least one element powder of metals from the group Cr, Mn, V, Si, Ti or of other metals which are at least as oxidation-sensitive by shaping, removing the binder and sintering. In place of an element powder, it is also possible to use an alloy powder comprising the corresponding metals.

Production of metallic shaped bodies by injection molding

The process for the producing improved shaped sintered articles by first shaping a) a mixture of a ceramic or metallic powder or mixtures thereof with a moldable thermoplastic composition containing b) a thermoplastic polyoxymethylene binder and c) a second moldable and essentially inert thermoplastic polymer having a melting point between 90.degree. and 220.degree. C., such as a polyether of bisphenol A and an aliphatic diol. The binder is then removed from the shaped article by exposure to a gaseous acid-containing atmosphere, preferably below its softening temperature, while the second inert thermoplastic polymer is retained as a source of elemental carbon in which the ceramic or metallic powder is finely dispersed. This retained polymer is then pyrolyzed under an inert gas at elevated temperatures of at least 600.degree. C. for conversion to a finely dispersed elemental carbon. The resulting pyrolyzed preformed product is then sintered to obtain the desired high density ceramic and/or metallic article as the final product in which elemental carbon is uniformly and finely distributed. The process provides a simpler and more easily controlled method of incorporating elemental carbon into the ceramic/metallic shaped and sintered product while also carefully controlling the initial shaping step to prevent any formaldehyde induced crosslinking in the thermoplastic binder composition.

Producing sintered articles from thermoplastic compositions containing

The preferred sintered parts made of oxygen-sensitive, non-reducible powders and their production by injection-molding are distinguished by the powders used being freed of their oxide layer by attritor milling in a water-free organic solvent, in the presence or absence of an additional reductant, the oxide particles being removed if necessary by filtration or screening in the presence of the organic solvent, the oxide-free powder being mixed as suspension with a polyacetal as binder under a protective gas, the organic solvent being distilled off, the mixture of powder and polyacetal being heated above the melting point of the polyacetal and being compounded to give a homogeneous composition, the granular material thus obtained being processed in an injection-molding machine made inert with argon to give shaped bodies, the shaped bodies being freed of binder under the action of oxalic acid in a closed ceramic container which nevertheless allows pressure equilibration under protective gas at atmospheric pressure or reduced pressure, the shaped bodies being, after binder removal, transferred in their container without contact with air into a sintering furnace and being sintered therein according to the prior art.

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Mannheim, Germany

Hans Wohlfromm