Post-Coagulation Washing and DMF Removal
topic
Post-coagulation washing removes residual DMF from coagulated PU-coated fabric through multi-stage counter-current water washing at increasing temperatures from 30 to 80 degrees Celsius, with the number of washing stages and wash water temperature determining the completeness of DMF extraction that must reduce DMF residue below 0.1 percent by fabric weight for occupational hygiene compliance in downstream processing and below the regulatory limit for finished consumer products.
Role
Ensures adequate DMF removal from finished coated fabric to meet regulatory residual solvent limits through systematic washing that must balance the washing efficiency required for compliance with the production economics of water consumption and energy cost, with DMF residue measurement by gas chromatography being the critical quality control test that verifies compliance before fabric proceeds to downstream finishing operations or customer delivery.