| 摘要 |
Paper having increased strength is made by adding aluminum sulfate and a paper strength agent containing a copolymer comprising (a) 98 to 60 % by mole of repeating units derived from (meth)acrylamide, (b) 1 to 20 % by mole of repeating units derived from at least one compound selected from the group consisting of alpha , beta -unsaturated monocarboxylic acids and their salts and alpha , beta -unsaturated dicarboxylic acids and their salts and (c) 1 to 20 % by mole of repeating units derived from a diallylamine derivative of the formula: <CHEM> wherein R1 and R2 are the same or different and hydrogen or methyl, R3 and R4 are the same or different and hydrogen or C1-C6 alkyl, and X<-> is an anion of an organic acid or an inorganic acid as an effective component to a pulp slurry and then making a sheet of paper from said slurry. |
