MECHANICAL PULP-CONTAINING PAPER AND ITS PRODUCTION

PROBLEM TO BE SOLVED: To obtain mechanical pulp-contg. paper capable of suppressing pitch troubles, excellent in sizability and improved in the yield of a neutral sizing agent, and to provide a method for producing the above paper. SOLUTION: This mechanical pulp-contg. paper is such one as to contain >=5 wt.% of mechanical pulp sized with a neutral sizing agent and also contain 0.03-1 wt.%, based on the mechanical pulp, of an additive comprising a cationic polymer, a vinyl-based copolymer composed of the respective constituent units corresponding to 50-95 wt.% of a hydrophobic monomer such as styrene-based monomer and 5-50 wt.% of cationic monomer(s) consisting of tertiary amino group-bearing monomer and/or quaternary ammonium salt-bearing monomer and containing a quaternary ammonium salt as well. The other objective method for producing mechanical pulp-contg. paper comprises using the above-mentioned additive and the cationic polymer at the aforementioned amount and sizing with a neutral sizing agent at pH 6-9.