Document kw3bZYJg78K7GodNe2KwpawJ

UNION CARBIDE CORPORATION CHEMICALS AND PLASTICS P O. BOX 471, TEXAS CITY, TEXAS 77590 September 28, 1967 r Y Mr. Warren Cook Institute of Industrial Health University of Michigan Medical Center Ann Arbor, Michigan k8lOk Dear Mr. Cook: Further to our conversation, I am enclosing a simplified flow diagram and process description of our solvent (solution) process for making VCl/VAc copolymers. No PVC is made by this process, although one maleic acid modified VCl/VAc resin is occasionally produced. Under separate cover, I am forwarding the suspension vinyl recipe information to Dr. Magnuson, If I can be of further service, please let me know. Yours very truly,' DER/sJ Enclosure cc: Dr. F. E. Bailey, Jr. Mr. J. H. Barrett Mr. 0, T. Carlisle Mr. Don Deese Dr. Bert Dinman Mr. J. F. Erdmann Mr. J. H. Field Dr. R, E. Joyner Dr. Harold J. Magnuson Mr. R. N. Wheeler Dean E. Richardson ROSS CASE CONFIDENTIAL ucc 020745 CONFIDE"'''TAL SOLVENT PROCESS VTE^^pOLYMERIZATIO SIMPLIFIED SCHEMATIC FLOW DIAGRAM CONFIDENT CONFIDENTIAL PROCESS NOTES SOLVENT (SOLUTION) VINYL PROCESS: The polymerization is carried out in acetone In jacketed, agitated lead-lined autoclaves. Acetone, monomers and catalyst solution (isopropyl peroxydicarbonate) are fed to the autoclaves continuously. The resin solution, a thick, clear, syrupy liquid, is withdrawn continuously and fed to a stripping column where un reacted monomers are stripped out by a countercurrent flow of hot acetone vapor. The resulting solution of polymer in acetone is centrifuged (clarified) to remove gels and foreign particles. In the processing unit, the resin is precipitated from the solution by adding isopropanol, after which the resin is dewatered in a continuous centrifuge. The dewatered resin is reslurried in water to remove residual solvents, after which the dewatering is repeated. The wet resin is dried in flash dryers, any oversized particles are removed and the finished resin is conveyed to a bin for storage. Like PVC, it is in the form of fine, white powder. FOR UNION CARBIDE CORPORATION: Dean E. Richardson 9-28-67 ROSS CASE CONFIDENTIAL ucc 020747