Gases in Coating Colors - Their Impact on Runnability and Their Measurement, 1999 Coating Conference Proceedings

Rainer Rauch

Reinhard Sangl

High gas levels in coating colors may cause runnability and quality problems. PTS has developed an automatically operating, portable on-line gas content meter that is capable of precision-measuring the gas content of coating colors within a broad range. The paper presents experimental results obtained under various conditions.

Depending on chemical and process parameters, gas contents between 4% and some 30% have been measured. High gas contents may have their origins in the coating color formulation, the coating color preparation, the color cycle, the application system and many others. Excessive gas levels are particularly critical in the case of jet applicators. These installations can only be operated when coupled with a mechanical color deaerator.

Targeted preventive measures and the use of mechanical deaerators and deaerator chemicals can successfully reduce gas levels in coating colors. Specifically, monitoring gas levels in coating colors enables the identification of gas sources so that preventive action can be taken and the application of chemical and mechanical deaerators be assessed and optimized. In laboratory measurements the propensity of coating colors to take up and/or stabilize gases can be determined.