Patent ID: 6565708
Filing Date: 2003-05-20
Classification: D21H

Abstract:
A process for producing a pulp sheet, which comprises adding a paper quality improver composition anytime before or in the papermaking step; wherein the paper quality improver composition comprises (A) a compound having a lyotropic degree, defined below, of not less than 4% and meeting at least two efficiencies selected from the following paper quality improving efficiencies (i) to (iii), (B) a water-soluble polymer satisfying at least one selected from an average molecular weight of 1000 to 10000000 and a viscosity of 1 to 4000 mPaÂ·s at 25Â° C. in a 1% aqueous solution thereof and optionally at least one surfactant (C); which composition is internally added before or in papermaking step;(i) standard improved bulky value of not less than 0.02 g/cm3, (ii) standard improved brightness of not less than 0.5 point, and (iii) standard improved opacity of not less than 0.5 point; and lyotropic degree (%)=(&agr;0âˆ’&agr;)/&agr;0Ã—100 wherein&agr;: the water content in a wet sheet obtained by adding 5 parts by weight of the compound which becomes the paper quality improver composition for the papermaking to 100 parts by weight of pulp and subjecting the resultant to the papermaking, and &agr;0: the water content in a wet sheet obtained by subjecting pulp to the papermaking without adding the compound which becomes the paper quality improver composition for papermaking to the pulp.