Comparison of different methods measuring the influences of fabric softener on the water absorbing properties
The application of fabric softener in the rinsing step is usually done for maintaining a soft hand in certain fabrics e.g. terry towels. Softener formulations can show a negative influence on the water absorbing properties. In this work, the water absorbing properties (water uptake and soaking velocity) of softener treated fabrics are determined according to two different standard methods. In addition a “short-time contact method” (STC method), especially suited for evaluating the water absorbing properties of terry towels, is presented. It is shown that this method is highly sensible and differences between different softener formulations can be emphasised.
Maintaining the soft hand of fabrics after repeated washing is a desirable feature for consumers. This is one of the reasons, that fabric softeners, which are available since the 1960´s, have gained importance (1-5). The harshness of textiles after the washing and drying procedure (dry stiffness) is caused by hydrogen bonds between the cellulose fibres and residues of alkaline earth ions. As new anionic and non-ionic surfactants were introduced in the laundry detergents the use of fabric softeners also became more frequent. These efficient surfactants leave the fabrics very clean after the washing as they reduce the residues of calcium soap and unsaponified fats on textile fibres and therefore increase the tendency of the fabric to remain hard and scratch (1-5). The application of a softener leads to the desired soft hand and can even be used to introduce other desirable properties like perfume and/or reduced electrostatic charging (during tumbler drying) or easy ironing/material protection (2, 4, 5).
The state of the art fabric softeners are cationic compounds based mostly on biological degradable esterquats. They comprise e.g. TEA ...