| 摘要 |
PROBLEM TO BE SOLVED: To provide an acrylamide-based paper-strengthening agent which has an excellent fixing property to pulp and is capable of exhibiting a high paper-strengthening effect even to pulp fiber slurry including a large amount of anionic foreign substances and having high electric conductivity, and to provide a method for producing paper using the same.SOLUTION: The paper-strengthening agent contains a (meta) acrylamide-based copolymer having a weight average molecular weight of 3.5 millions to 8 millions obtained by copolymerization of polymerization components including (meta) acrylamide, a cationic vinyl monomer, an anionic vinyl monomer, and a chain transferring monomer. When the concentration of the (meta) acrylamide-based copolymer is 0.2 wt% and pH is 7.0 (25°C), the paper-strengthening agent has a measured potential of 200 mV or less by a PCD electrometer. |
