WATER-BASED COATINGS - PROBLEMS AND SOLUTIONS

Converters can attain compliance with EPA directives by using waterborne coatings. Problems encountered when using waterborne coatings include poor wetting, poor machinability, and longer drying/curing times. Wetting can be improved by adding small amounts of low-surface-tension solvents. Poor machinability can be handled through reformulation of the coating to one that is inherently low foaming. This is done by using defoamers and, occasionally, small amounts of solvent. Drying problems can be corrected through solvent adjustment, line adjustments (higher oven-air velocity), catalysis, or use of higher-molecular-weight crosslinkers. 4 Refs.