Continuous process for the one-shot preparation of a thermoplastic noncellular polyurethane
Abstract
Abstract A CONTINOUS PREPARATION OF THERMOPLASTIC MONOCELLULAR POLYURETHANES IS DISCLOSED. THE REACTION COMPONENT ARE MIXED IN THE LIQUID STATE AND PASSED THROUGH A HIGH SHEAR MIXING ZONE AND THEN THROUGH ANDEXTRUSION ZONE. THE TEMPERATURE OF THE REACTION MIXTURE IS CONTOLLED DURING PASSAGE THROUGH THE MIXER AND EXTRUDER IN SUCH A MANNER THAT THE VISCOSITY OF THE REACTION MIXTURE REMAINS SUBSTANTIALLY CONSTANT THROUGHOUT THE MIXING AND EXTRUSION ZONES; THIS REQUIRES A TEMPERATURE GRADIENT IN THE VARIOUS ZONES RISING FROM A LOW OF ABOUT 200*F. AT MIXING TO ABOUT 400-450*F. AT THE POINT OF EXTRUSION. IN A PREFERRED EMBODIMENT THE REACTION IS CARRIED OUT IN A COMBINATION OF HIGH SHEAR MIXER OAN TWIN-SCREW EXTRUDER. THE THERMOPLASTIC POLYURETHANE IS PREFERABLY EXTRUDED AS A STRAND WHICH IS COOLED BELOW ITS MELTING POINT AND PELLETIZED.
Inventors
- 👤 Karl W Rausch Jr
- 👤 Thomas R Mcclellan
Bibliographic Details
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