Comparative Case Study on Adhesion of Three Common Sizing Agents to Cotton and Polyester Yarns

The adhesion between warp sizing and fiber was systematically studied by using the roving method. Cotton roving and polyester roving were sized with various concentrations between 0.01% and 2.50% of acid-thinned starch, polyvinyl alcohol and water-soluble polyester sizing, respectively, and tensile property of the sized roving was tested accordingly. The break force of the sized roving was considered as the adhesion force of the sizing to the fiber in the roving method. The experimental results show that the effects of sizing film strength and fiber strength on the adhesive force can be weakened when the concentration 0.5% of size paste is used, instead of 1% in the roving method. The size morphology in the sized roving and on the surface was observed through scanning electron microscopy, in the form of penetration and coverage of the sizing in or on the roving. On the other hand, the Young-Dupré equation was used to calculate the adhesion work. The advantages and disadvantages of roving method and the adhesion work method were compared. The adhesion obtained by both two methods reflects the rule of chemical similarity between warp sizing and fiber.