Method and expansion device for preparing expanded thermoplastic microspheres
AssigneeAkzo Nobel N.V.
InventorsLars-Olof Svedberg, Guy Hovland, Thomas Holmlund
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Abstract
The present invention relates to a method of preparing expanded thermoplastic microspheres, comprising charging thermally expandable microspheres into an expansion device comprising rotating feeding means enveloped by a hollow body, and one or more scrapers. The invention further relates to an expansion device for expanding thermoplastic microspheres.
Claims27
A method of preparing expanded thermoplastic microspheres, comprising the steps of:
- (a) charging thermally expandable microspheres into an expansion device comprising rotating feeding means enveloped by a hollow body, and one or more scrapers preventing layers of microspheres being built-up in the expansion device,
- (b) transporting the microspheres through the expansion device while increasing the temperature of the microspheres to achieve expansion thereof, and,
- (c) discharging the microspheres.
A method of preparing expanded thermoplastic microspheres, comprising the steps of:
- (a) pre-mixing thermally expandable microspheres with a filler preventing agglomeration of the microspheres,
- (b) charging the microspheres into an expansion device comprising rotating feeding means enveloped by a hollow body, and one or more scrapers preventing layers of microspheres being built-up in the expansion device, said one or more scrapers, alone, or in combination, effect a scraping of from about 20 to about 95% of the longitudinal length of the inner surface of the hollow body, the hollow body is provided with one or more heaters,
- (c) transporting the microspheres through the expansion device while increasing the temperature of the microspheres to achieve expansion thereof, and,
- (d) discharging the microspheres.
An expansion device for preparing expanded thermoplastic microspheres comprising rotatable feeding means enveloped by a hollow body, and one or more scrapers positioned between the outer radius of the feeding means and the inner surface of the hollow body.
Dependencies are inferred from the claim text.