Quantifying Water Repellency by Modifying Spray Test Method AATCC TM22 to Extend Test Duration Allowing Discrimination between Similarly Graded Fabrics

The AATCC TM22-2014 spray test (similarly BS EN ISO 4920:2012) is widely used to determine the water repellency of textiles. Given the ongoing move towards non-fluorinated chemistries to provide water repellent finishes on textiles, modifications to the spray test are suggested to discriminate between those which initially demonstrate similar repellency and aid in assessment of performance within laboratory textile testing. An extended shower duration of 60 minutes or 120 minutes is recommended, with additional calculations to objectively quantify surface wetting. This increased test period demonstrated differences in performance between repellent finishes with a 1.37 g mass difference between fluorinated and non-fluorinated chemistries after 120 minutes. Further quantification of repellent performance, as set out in this study, would determine the performance of non-fluorinated durable water repellent (DWR) chemistries and suitability for end use.