Effects of coating process on the surface roughness of coated fabrics

Roughness of textiles and garments is an important parameter influencing consumer choice. This work considers the effect of applying a polyurethane coating on the surface roughness of woven polymer fabrics. A number of different process parameters were tested, including curing temperature, gap spacing, coating speed and viscosity of the coating paste. The Kawabata Evaluation System for Fabrics (KESF) was used to measure fabric surface roughness. By selecting appropriate process parameters, coatings with low roughness can be obtained. We show that, fabric type and microstructure are the major determining factors of surface roughness. Our multivariable testing also revealed a complex and nonlinear correlation between the thickness of coatings and their surface roughness, which we explain invoking a physical mechanism which takes into account the microscale interactions between fabric filaments and the coating paste that occur throughout the curing process.