Method for producing a shaped body from a polycondensate
First Claim
1. A method for manufacturing a molded part, in particular a profile, out of a polycondensate, wherein the polycondensate is melted and later solidified again during the process, characterized in that the overall time for which the temperature of the polycondensate exceeds the melting point of the polycondensate during the process measures less than about 60 seconds.
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Abstract
The invention relates to a method for producing a shaped body, particularly a profiled piece, from a polycondensate, particularly a polyester such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT) or one of the copolymers thereof. According to the invention, the polycondensate is melted over the course of the method and, later, is rendered solid once again. The invention is characterized in that the total time, during which the temperature of the polycondensate over the course of the method is higher than the melting temperature of the polycondensate, is less than approximately 60 seconds. The method is preferably carried out by means of a multiple screw extruder, whereby the degassing and/or drying of the polycondensate ensues in the solid state at a pressure less than the atmospheric pressure and/or while adding an inert gas. The period of time during which the polycondensate dwells in the extruder after having been melted therein is less than approximately 15 seconds.
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Citations
23 Claims
- 1. A method for manufacturing a molded part, in particular a profile, out of a polycondensate, wherein the polycondensate is melted and later solidified again during the process, characterized in that the overall time for which the temperature of the polycondensate exceeds the melting point of the polycondensate during the process measures less than about 60 seconds.
Specification