Automated AUP (absorption under pressure): A novel method to characterise superabsorbent polymers

Superabsorbent polymers (SAPs) are a key constituent in baby diapers and adult incontinence products. To develop new SAPs, lab tests are used to measure properties that are considered important for these products. However, these manual tests are often time-consuming and tedious. This paper introduces an automatic method to measure absorption under pressure (aAUP) using industry robots. The new robotic method addresses limitations in an industry standard absorption under pressure (AUP) method. The new aAUP method can run continuously, generating more and better data to aid in product development. It enables to put the Buchholz theory on SAPs for predicting their properties to practice by reduction of manual effort and by producing excellent data quality. This has been shown on commercial polymers from different production processes, with varied particle size distributions and shapes. The aAUP data has also been shown to accurately predict other properties of SAPs relevant for their application in hygiene articles, making it a useful tool for understanding the underlying science and facilitating product development.