| 摘要 |
PROBLEM TO BE SOLVED: To prevent the adhesion of pitch, eliminate spots on paper, improve the paper quality and improve the productivity and workability by adding a specific water-soluble anionic copolymer to a pulp slurry, mixing the components and adding a water-soluble cationic polymer to the mixture to effect the control of pitch. SOLUTION: A water-soluble anionic copolymer such as a sodium salt of a copolymer of (i) a water-soluble unsaturated carboxylic acid compound such as (meth)acrylic acid and (ii) a 4-23C water-insoluble vinyl compound such as anα-olefin or a (meth)acrylic acid ester (the molar ratio of (i)/(ii) is preferably 20/80 to 80/20) is added to a pulp slurry. The mixture is thoroughly mixed and incorporated with one or more kinds of water-soluble cationic polymers selected from polymers (salts) of formulas I to III (X<1> and X<2> are each Cl or Br; X<3> is X<1> , sulfate residue, etc.; R<1> to R<3> are each H or a 1-5C alkyl; (p), (q) and (r) are each a polymerization degree) and a polycondensation product of dicyandiamide-formaldehyde-ammonium chloride to effect the pitch control.
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