PAPER DURABILITY PROMOTER FOR HIGH ASH CONTENT PAPER, MANUFACTURING METHOD OF HIGH ASH CONTENT PAPER AND HIGH ASH CONTENT PAPER

摘要

PROBLEM TO BE SOLVED: To provide amphoteric polyacrylamide making pulp easy to fix, hardly disturbing formation and excellent in paper durability effect even with high ash content.SOLUTION: There is provided a paper durability promoter that contains an amphoteric polyacrylamide having requirements [1] to [5]. [1] acrylamide (a), an α methyl group-containing cationic vinyl monomer (b) and an anionic vinyl monomer (c) are contained. [2] a ratio of the (b) component is 1-15 mol% and a ratio of the (c) component is 1-10 mol%. [3] There are high magnetic field side absorption band A and low magnetic field side absorption band B assigned to an α methyl group of the (b) component ofH-NMR spectrum and an area of A (As) and an area of B (Bs) is [As/(As+Bs)]=10-35%. [4] a viscosity of 15 wt.% solution (25°C) is 2,000-60,000 mPa a. [5] a ratio between a weight average molecular weight (Mw) and a number average molecular weight (Mn), (Mw/Mn) is 3.5 or less.SELECTED DRAWING: Figure 2