To improve weavability to the warp and /or to overcome inherent deficiencies of the yarn to withstand the stresses and strains of weaving.This can be attained by improving primarily the abrasion resistance of the yarn.
This in turn is achieved with the formation of a film around the yarn along with some penetration of sizing chemicals.
Color fastness tests are carried out according to specified tests methods of AATCC, ISO,DIN,M&S,ASTMD etc: