Foam application from a closed system – a study of machine and foam parameters
An attempt has been made to gain a greater insight into the interaction between foam and a moving textile substrate. The effects of changing wet pick–up, fabric velocity, liquid viscosity, foam density and mode of application on penetration have been studied. Application from a closed system makes it possible to apply an exact amount of liquid, and reflectance measurements revealed that between 10 and 60% wet pick–up the actual level of wet pick–up is of major importance. The amount of liquid available determines the likelihood of capillary transport. The results obtained in terms of fabric speed and foam density still leave questions to be answered on the mechanisms of foam flow and degradation in the textile.
Absorption and rheological phenomena during foam application on textiles
A simple rheological model has been used to describe foam flow through moving textile assemblies. The validity of this model was tested, and the nature and the relative magnitude of deviations from the model evaluated for several different substrates. Neglecting foam degeneration during transport, the model was found to represent a valuable means of evaluating some rheological and geometrical deviations. The model can be used in a semi-quantitative way to describe absorbency during foam application. Liquid absorption experiments done off-line, absorption during foam application and some earlier results could be described using different theoretical approaches. Some rheological anomalies have been discussed.
The Wettability of Scoured and Dried Cotton Fabrics
The effect of scouring and drying on the wettability of cotton fabric is examined. The phenomenon of hydrophilicity is mainly determined by the competitive effects of spreading among the fibers and absorption in the fibers. Special attention is paid to the influence of surface active agents. A number of tests covering both aspects of the wetting process are discussed.