Effect of the PVA Impregnation Treatment Conditions on the Strain and Physical Properties of Paper

Abstract

Strain is one of the most important factors in deforming a sheet-like paper into a three-dimensional structure. This study evaluated the changes in the strain and physical properties according to the impregnation treatment conditions using a base paper made of cotton fibers. PVA (polyvinyl alcohol) was used as the impregnating liquid, and borax was used as its hardening liquid. Boric acid and caustic soda were used to control the pH of the borax liquid, and glycerine was used to control PVA’s degree of hardening.<BR>The results showed that the strain in the machine driection (MD) direction decreased as the pH of the hardening liquid increased. The tensile index and the rupture indexs were highest at pH 8.5. The strain, tensile and rupture indexes according to the borax concentration were the higher value at 0.5% in the MD direction and 1.0% in the cross direction (CD) direction. However, the tear index continued to decrease as the borax concentration increased. The strain increased as glycerine concentration of the hardening liquid increased, and the tensile and the rupture indexs showed opposite trends. The strain and the physical properties were greatly affected by the pH, borax, and glycerine concentration of the hardening liquid.