| 摘要 |
The present invention is directed to the use of continuous extrusion devices to form high quality polymer dispersions. 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 polymer dispersions. |
| 主权项 |
1. A method for producing an emulsion of plasticized poly(vinyl butyral) in water comprising:
feeding into a screw extruder a thermoplastic polymer resin, a plasticizer, a surfactant, and water, wherein said thermoplastic polymer resin is a poly(vinyl butyral) resin having a weight average molecular weight of at least 40,000 Daltons; mixing said polymer resin, said surfactant, said plasticizer, and said water in a first zone within said screw extruder to form a weld; moving said weld to a second zone within said screw extruder; adding water to said weld in said second zone and mixing, thereby causing an inversion in said weld which results in the formation of said emulsion of plasticized poly(vinyl butyral) in water; wherein said polymer resin, said surfactant, said plasticizer, and said water are moved into and through the first zone, to mix the components and form said weld, in less than about 45 seconds; wherein said first zone is set at a pressure of 2×106 Pascal to 4×106 Pascal and a temperature below 100° C.; and wherein said second zone is set at a pressure of 2×106 Pascal to 4×106 Pascal and a temperature below 100° C.
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