3m Innovative Properties Company

Minnesota Mining and Manufacturing Company

Eugene E Harkins

David R Holm

Ross M Kedl

Robert Stephen Davidson

Albert E Seaver

Daniel T Chen

William R Berggren

Daniel R Danielson

A continuous, preferably counter-current, extraction process that can be used to significantly reduce the concentrations of residual monomers, residual catalyst, undesired solvents, and other impurities in polymer compositions. The invention is particularly beneficial for extracting residual monomers and other impurities from viscous, sticky polymer solutions, such as solutions of PSAs and low cohesive strength polymer compositions that phase change during extraction (i.e., change from liquid to solid, or precipitate), in a continuous manner. The polymer composition can be extruded into an extraction solvent as fibers in a vertical extraction column, under conditions such that at least a portion of an impurity is extracted from the polymer into the extraction solvent.

Process for removing impurities from polymers

An electrospray coating head system for applying thin coating to a substrate comprising a slot or blade to meter a liquid onto a shaping structure which forces the liquid to have a single continuous and substantially constant radius of curvature around the shaping structure. A voltage applied to the liquid around the shaping structure causes the liquid to produce a series of filaments which are spatially and temporally fixed, the number of filaments being defined by a simple adjustment in the applied voltage. The filaments break up into a uniform mist of charge droplets and are driven to a substrate by electric fields to produce a coating. Also a method for electrospray coating wherein liquid to be coated is dispensed from a metering portion to a lower shaping means where it achieves a single continuous and substantially constant radius of curvature, a voltage is applied to produce a series of filaments of the liquid which are spatially and temporally fixed, and the filaments break up into a uniform mist of charge droplets.

Electrospray coating apparatus and process utilizing precise control of

Growing community of inventors

Vadnais Heights, MN, United States of America

Eugene E Harkins