Method for the direct and continuous production of hollow articles from a polymer melt
AssigneeLurgi Zimmer GmbH
InventorsBrigitta Otto, Roland Schäfer, Holger Bachmann, Ludwig Hölting, Stefan Deiss
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Abstract
A method of making shaped articles from highly condensed polyester melt and especially preforms for the blow molding of food and especially beverage containers. A melt is continuously withdrawn from the polycondensation reactor and is fed to the shape-imparting units, especially a multiplicity of injection-molding machines without solidification between the final reactor and the injection molders and without degassing between the final reactor and the injection molding machines.
Claims24
A method of making molded articles of high-condensation polyester having an acetaldehyde content in a preform of high-condensation polyester of a maximum of 8 ppm, the method comprising the steps of:
- (a) producing a melt of a high-condensation polyester in a polycondensation reactor system and outputting the high-condensation polyester melt from a final stage of a high-viscosity self-cleaning or double-drive reactor;
- (b) flowing the outputted high-condensation polyester melt without any solidification or degasification from said final reactor stage to a molding unit;
- (c) adding an acetaldehyde-reducing substance or a mixture of acetaldehyde-reducing substances one or at most two times to the high-condensation polyester melt flow downstream of the final reactor stage and upstream of the molding unit;
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- (d) thereafter introducing the high-condensation polyester melt flow with the acetaldehyde-reducing substance into the molding unit and shaping said molded articles from said high-condensation polyester melt in said molding unit.
A method of making molded articles of high-condensation polyester, the method comprising the steps of:
- (a) producing a melt of a high-condensation polyester in a polycondensation reactor system and outputting the high-condensation polyester melt from a final reactor stage of a high-viscosity self-cleaning or double-drive reactor;
- (b) forming a main flow of 50 to 100% of the high-condensation polyester melt outputted by the final reactor stage;
- (c) diverting 0 to 50% of the high-condensation polyester melt outputted by the final reactor stage selectively to an esterification stage or to a granulation stage to control a pressure of the;
- (d) subdividing said main flow at least once into an even number of substreams and feeding same to respective molding units;
- (e) adding to each substream of the high-condensation polyester melt before it enters the respective molding unit and after a last subdivision an acetaldehyde-reducing substance or mixture of acetaldehyde-reducing substances in solid form or as a slurry including an acetaldehyde-reducing substance;
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- (f) preventing any solidification or degasification of the high-condensation polyester melt in the main flow and subflows between said final reactor stage to each molding unit.
Dependencies are inferred from the claim text.