Methods and devices for continuous production of polymeric dispersions

摘要

The present invention is directed to the use of continuous extrusion devices to form high quality polymer dispersions of polyvinyl butyral), a surfactant, and a plasticizer. Screw extruder devices of the present invention inject water into a zone of high pressure, temperature, and shear to cause the rapid inversion of a weld in less than, for example, one minute, which compares very favorably with conventional batch methods, which can take, for example, two or more hours to complete an inversion. This rapid inversion—a surprising result given the extended time inversion requires in batch processes—allows for the continuous production of poly(vinyl butyral) dispersions.

主权项

1. A method for producing a dispersion of poly(vinyl butyral) in water comprising:
(a) feeding said poly(vinyl butyral), a plasticizer, a surfactant, and initial water into a screw extruder; (b) mixing said poly(vinyl butyral), said plasticizer, said surfactant, and said initial water in a first zone within said screw extruder to form a weld, wherein said weld forms in less than 45 seconds; and (c) contacting additional water with said weld in a second zone within said screw extruder to thereby cause an inversion of said weld and the formation of said dispersion.