Paper strength enhancer for high-ash paper, method for producing high-ash paper, and high-ash paper

Abstract

The purpose of the present invention is to provide a new type of amphoteric polyacrylamide which can be easily fixed in pulp even in a high ash environment, is not easily disturbed into paper texture, and has excellent paper strength effect. A paper strength enhancer for high ash paper containing amphoteric polyacrylamide that meets the following requirements [1], [2], [3], [4] and [5]: [1] its component (1) contains propylene Amide (a), α-methyl-containing cationic vinyl monomer (b), anionic vinyl monomer (c); [2] The ratio of component (b) in component (1) is 1-15 mol%, and the ratio of (c) component is 1 to 10 mol%; [3] in which 1 In the range of 0.9ppm to 1.35ppm in the H-NMR spectrum, there is an upper magnetic field side absorption band A and a lower magnetic field side absorption band B attributed to the α methyl group of the (b) component, and the ratio of the area of ​​the signal As / (As+ Bs) is 10 to 35%; [4] the viscosity of its 15% by weight aqueous solution (25° C.) is 2,000 to 60,000 mPa·s; [5] the ratio of its weight-average molecular weight (Mw) to number-average molecular weight (Mn) ( Mw / Mn) is 3.5 or less.

Description

technical field [0001] The invention mainly relates to a paper strength enhancer for high-ash paper, a manufacturing method of high-ash paper and high-ash paper. Background technique [0002] Inorganic fillers such as talc, kaolin, and calcium carbonate are generally used in paper such as printing paper and note paper. In particular, calcium carbonate has an excellent effect on the opacification, whitening and smoothness of paper, and can improve printing adaptability. Therefore, the amount of calcium carbonate used in the paper industry has a tendency to increase year by year. Hereinafter, paper containing a large amount of inorganic filler is referred to as "high ash paper". [0003] However, as the content of inorganic filler increases, high-ash paper tends to decrease in tensile strength and internal strength. As a result of the presence of a large amount of inorganic fillers between pulp fibers, it can be considered that the entanglement and hydrogen bond-mediated int...

AI Technical Summary

Problems solved by technology

However, it has been found that although the paper strength enhancer is suitable for the aforementioned high-ash paper, especially paper containing a large amount of calcium carbonate as an inorganic filler, the desired effect may not be achieved in some cases.

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