Contamination of paper machine press fabric materials by ASA studied with a new deposition tester

The contamination of paper machine press fabric materials by alkenyl succinic anhydride (ASA) in different environments was studied using a new deposition tester. X-ray photoelectron spectroscopy (XPS), infrared spectroscopy and contact angle measurements were performed to analyze clean and contaminated press fabrics. The results showed that the use of ASA or calcium carbonate filler alone did not result in especially severe contamination. However, when both ASA and calcium carbonate were present, fouling was drastically increased. Also, introducing Ca²⁺-ions with ASA in weakly alkaline solutions (pH 8.5) resulted in notable contamination, whereas this was not clearly seen in acid solutions (pH 4.0). Thus, the main mechanism behind the remarkable contamination by ASA at alkaline conditions could be associated with the formation of metal soaps of ASA. The results obtained with the new laboratory tester indicated trends similar to those observed in more fundamental laboratory experiments. As the tester can also be used to evaluate surface material performance on production scale by performing mill trials using paper machine by-pass flows, it provides a direct connection from fundamental interactions to mill scale applications in contamination testing.