PRINTABILITY IMPROVING AGENT OF PAPER AND CARDBOARD

PURPOSE: To obtain the subject agent for improving printability, in particular gravure and roll offset printings by including each specified amount of water and a mixture essentially comprising an organic quaternary ammonium salt, etc., and an anionic group-contg. water-soluble or water-swellable polymer. CONSTITUTION: This agent for improving the printability of paper and paperboard is obtained by including (A) 50-95 wt.% of water and 5-50 wt.% of a mixture of (B) 1-50 wt.% of a mixture of (i) an organic quaternary ammonium salt containing at least one 8-22C alkyl group and (ii) a mixture of 50-99.5 wt.% of the above organic quaternary ammonium salt and 0.5-50 wt.% of a (un)saturated 8-22C fatty acid, an oxidized wax or a polyglycol with a molecular weight of >4,000, or (iii) a mixture of 50-99.5 wt.% of an organic amine partially neutralized with a mineral acid or a lower carboxylic acid and 0.5-50 wt.% of an saturated 8-22C fatty acid, an oxidized wax or a polyglycol with a molecular weight of >4,000 and (C) 50-99 wt.% of an anionic group-contg. water-soluble or water-swellable polymer.