Wash fastness of fluorocarbon finishes on polyester fabrics

A fabric's surface tension provides a measure of its ability to repel water and oil, while water penetration can be evaluated from a fabric's hydrostatic pressure, which depends mainly on the pore size and thus on the weave. One way of making a surface hydrophobic is to coat it with fluorinated polymers, which confer a low surface tension, reducing the fabric's wettability while preserving its breathability. We have shown that polyester microfibre fabrics (which already have a tight weave and hence high hydrostatic pressure) can be treated with fluorinated finishes to increase water and oil repellency. Observation of a piece of fluorinated polyester microfibre fabric over a number of washings has shown that a regenerative heat treatment preserved the repellency of the fabric but had little influence on the decrease in hydrostatic pressure that occurs with washing.