Paper sizing prepn. - contains conventional sizing agent and special aluminium citrate as size improver

摘要

A sizing prepn. (I) is claimed, contg. a normal sizing agent (II) and 0.0025-2.0 pts. wt. Al citrate (III) contg. 0.3-2 mols. citric acid/Al atom (w.r.t. 0.25 pts. wt. solid II). Pref. (I) contains aq. starch soln., 0.1-5.0 wt % (II) (solid) and 0.002-5.0 wt.% (III); (III) is obtd. by reaction of 1 mol. Al(OH)3 with 0.3-2.0 (pref. 0.5-1.5) mols. citric acid in the presence of 0-2.0 (pref. 0-1.0) mols. orthophosphoric acid, pref. in 25-90% aq. soln. at 50-180 deg.C; (II) is an anionic or cationic size. (II) is e.g. a soln. or dispersion of resin size, a prod. based on fatty acid or amide, diketene, protein, polysaccharide, alkenylsuccinic anhydride, maleic anhydride copolymer, (meth)acrylamide (co)polymer etc., (III) is added to the pulp before, with or after (II). USE/ADVANTAGE - The addn. of (III) gives a sizing prepn. with improved sizing values, suitable for alum-contg. or alum-free pape