Abstract: An aqueous surface sizing composition for sizing paper or paperboard having as essential components 50 to 70 pads of a water soluble or water dispersible hydroxylated polymer, an amount of a carboxylated polymer that is present relative to hydroxylated polymer in a ratio of 0.5:99.5 to 4:96 and not exceeding 7 pads carboxylated polymer, 0.3 to 3.0 pads of an alkali salt of a Group IV metal (e.g., zirconium, hafnium, and titanium), and sufficient water to obtain 1.5 to 2.0 percent total solids. The sizing compositions may further include polymeric additives, aqueous alkali, a pigment and a defoamer.

Abstract: This invention relates to an improved process of surface sizing of paper and paperboard. The process consists of:a) Preparing an aqueous surface sizing compound by combining and mixing an aqueous solution of at least one water soluble or dispersible polymer or interpolymer, a solution or dispersion of auxiliary materials, and an aqueous solution of a metal salt, selected from the group of metals consisting of zirconium, hafnium or titanium, to the polymer solution;b) Adjusting the pH of the aqueous sizing compound from about 5 to about 10.