Method for making thixotropic materials
AssigneeThe Dow Chemical Company
InventorRobert S. Busk
Life of this patent
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Abstract
A process for forming a liquid-solid composition from a material which, when frozen from its liquid state without agitation, forms a dendritic structure. A material having a non-thioxotropic-type structure, in a solid form, is fed into an extruder. The material is heated to a temperature above its liquidus temperature. It is then cooled to a temperature less than its liquidus temperature and greater than its solidus temperature, while being subjected to sufficient shearing action to break at least a portion of the dendritic structures as they form. Thereafter, the material is fed out of the extruder.
Claims10
A process for the production of liquid-solid material comprising (a) feeding a solid material having a dendritic structure into a screw extruder;
- (b) passing said material through a feeding zone in the extruder;
- (c) heating said material to a temperature greater than its liquidus temperature as it passes through a heating zone in the extruder;
- (d) cooling said material to within a temperature range of greater than the solidus and less than the liquidus temperature of the material;
- (e) shearing said cooled material in the extruder with the screw at a force sufficient to break at least a portion of the dendritic structures as they form;
- and (f) removing said material from said extruder.
A process for the production of liquid-solid metal alloy comprising (a) feeding a solid metal alloy having dendritic structures into a screw extruder;
- (b) passing said alloy through a feeding zone in the extruder;
- (c) heating said metal alloy to a temperature greater than its liquidus temperature as it passes through a heating zone in the extruder;
- (d) cooling said alloy to a temperature range of greater than the solidus and less than the liquidus temperatures of the alloy;
- (e) shearing said cooled metal alloy with the screw at a force sufficient to break at least a portion of the dendritic structures as they form;
- and (f) removing said alloy from said extruder.
A process for the production of a liquid-solid metal alloy comprising (a) feeding solid metal alloy having dendritic structures into an extruder;
- (b) passing said alloy through a feeding zone in the extruder;
- (c) heating said metal alloy to a temperature greater than its liquidus temperature as it passes through a heating zone in the extruder;
- (d) cooling said alloy to a temperature range of greater than the solidus temperature and less than the liquidus temperature of the alloy;
- (e) shearing said cooled metal alloy with rotating plates at a force sufficient to break at least a portion of the dendritic structures as they form;
- and (f) removing said alloy from said extruder.
Dependencies are inferred from the claim text.