Paper strength enhancer, paper strength enhancer manufacturing method, paper

摘要

A novel amphoteric polyacrylamide type paper strengthening agent, which is liable to left in paper pulp, is not liable to turn the zeta electric potential of the paper pulp into positive, is excellent in paper strengthening effects and does not disorder texture of paper, is provided. The paper strengthening agent comprises amphoteric polyacrylamide satisfying following essential conditions [1] to [3]: [1] acrylamide (a), a cationic vinyl monomer (b) containing alpha methyl, an anionic vinyl monomer (c) and a crosslinking monomer (d) are adopted as components; [2] the component (b) is 1-20% by molar of the amphoteric polyacrylamide; and [3] a range of 0.9-1.35 ppm of a 1H-NMR spectrum of the amphoteric polyacrylamide comprises a high-field side absorption band A and a low-field side absorption band B belonging to the alpha methyl in the component (b), and the area (As) of the absorption band A and the area (Bs) of the absorption band B satisfy that the As/(As+Bs) is higher than 20%.