Effect of fabric structure on liquid transport, ink jet drop spreading and printing quality

Sorption is an important performance property of apparel fabrics. Different techniques have been developed and used to characterize and compare the liquid transport or sorption properties of textile structures. The influence of different chemical treatments and finishes on absorption properties of yarns and fabrics has also been studied using these techniques. Although liquid transport studies have been carried out on different fabrics, the influence of fabric structural features has not been fully explored. Further, almost all of the previous liquid transport studies consider textile assemblies as single capillaries, even though these materials consist of capillaries that vary in diameter and length and are interconnected in a complex manner. The phenomenon of liquid migration during sorption from one yarn to another yarn and back to the first yarn is often overlooked despite the fact that it is an important part of the sorption process in fabrics. This work focused on the effect of fabric structure and yarn-to-yarn liquid migration on the overall liquid transport behavior of fabrics. Sorption of liquid from an unlimited reservoir as well as sorption of a limited quantity of liquid by fabrics representing different structural parameters has been studied. Absorption of liquid from an unlimited reservoir is studied by the weight balance and image analysis techniques and the results obtained for the two techniques are compared. Sorption of a limited quantity of liquid is studied by performing drop spreading experiments on fabrics. The spreading and wicking of micron sized drops deposited on fabric surfaces during ink jet printing is also studied. The nature of influence exerted by the fabric structure related variables on the spreading behavior of ink drops and how exactly the spreading influences printing quality has been xviii investigated. The influence of spreading behavior on dithering of ink was studied by printing solid figures on experimental fabrics. Further, an attempt was made to relate the quality of lines printed on fabrics to the observed sorption behavior of ink from limited and unlimited supply sources. Results showed that wicking in fabrics is determined by the wicking rates of yarns, thread spacing, and more importantly by the rate at which liquid migrates from longitudinal to transverse threads and again from transverse threads back to longitudinal threads. Comparison of wicking results obtained by weight balance and image analysis methods showed that weight balance method cannot be used in place of image analysis method, especially when measuring the wicking properties of more open fabrics. While drop spreading rates were dependent on fabric structure, the relation between drop spreading rate and fabric structure was found to be very complex in nature. In general, thin and compact cotton fabrics showed the highest values for drop spreading rate. Higher drop spreading rates were also observed in thin polyester fabrics. Drop spreading rates were found to be influenced primarily by the phenomenon of liquid migration from yarn to yarn. Ink jet printing of experimental fabrics with pigment ink showed that fabrics whose yarns are characterized by narrow and continuous surface capillaries give raise to excessive drop spreading and higher line widths. Thus yarn surface characteristics were found to play a greater role than fabric construction parameters in determining the quality of ink jet printing.