| 摘要 |
PURPOSE: To produce a paper in improved drainage rate, yield and paper strength while suppressing the staining of the paper-making system by using a water-soluble aluminum salt and a neutral sizing agent for paper-making consisting of a rosin ester and chitosan. CONSTITUTION: A neutral sizing agent for paper-making is prepared from (A) a rosin substance consisting of (i) a rosin and (ii) a reaction product containing a rosin ester and produced by the reaction of a rosin with at least one kind of polyhydric alcohol such as glycerol or said polyhydric alcohol and at least one kind of anα,β-unsaturated carboxylic acid and/or its derivative such as maleic anhydride and containing >=10wt.% of the rosin ester based on the sum of the components (i) and (ii) and (B) a chitosan having a deacetylation degree of 40-100% and a molecular weight of 2,000-500,000 and/or its salt. This neutral sizing agent and a water-soluble aluminum salt are added to a pulp slurry of pH6.5-9 and a paper is produced from the slurry. As an alternative, the paper is produced by using the rosin substance in a state separated from the chitosan and the water-soluble aluminum salt.
|
