Surface-sizing paper

摘要

PURPOSE: To effectively obtain a high-grade paper in a high yield from reusable waste paper by treating a surface-flat structure made of paper stuff with a sizing composition containing chitosan and a specified complex as sizing active components. CONSTITUTION: A surface-flat structure having at least 60 g/m<2> weight (e.g. cardboard, board or the like) is obtained using wood fibers, reusable waste paper or the like, as raw materials. (A) Chitosan preferably having a molecular weight of 5×10<5> -5×10<6> protonated with hydrochloric acid, acetic acid or the like and (B) a (12-22C fatty acid)-Cr (III) complex obtained by allowing a 12-22C fatty acid to react with basic chromium chloride in alcohol are blended in a weight ratio A:B of 1:0.2 to 1:5 (the component A shows weight before protonation). The blend is adjusted to pH 3-6, applied to the surface of the structure by 0.005-0.3 g/m<2> with an air knife or the like and dried to obtain the objective paper.