Waste pvb processing method

Abstract

A method of processing PVB, in particular waste PVB, comprises providing post-consumer or post-industrial PVB, e.g., in the form of flakes or granules, extracting plasticizer from the PVB with supercritical carbon dioxide, i.e., carbon dioxide at a temperature above its critical temperature of 31° C. and pressurized above its critical pressure of 7.3773 MPa (73.773 bar). The extraction may be carried out with supercritical CO2 at a pressure in the range from 80 to 500 bar, preferably from 100 to 450 bar, more preferably from 150 to 400 bar, and at a temperature in the range from 33° C. to 70° C., preferably from 35° C. to 60° C., and more preferably in the range from 38° C. to 45° C.

Dependencies are inferred from the claim text.