| 摘要 |
PROBLEM TO BE SOLVED: To provide a pitch controlling agent capable of preventing aggregation of pitch particles and colloidal pitch in process water of paper pulp by improving dispersibility of the pitch particles and the colloidal pitch and a pitch controlling method using the agent. SOLUTION: This pitch controlling agent is characterized by including a water-soluble polyvinyl alcohol obtained by copolymerizing (A) a vinyl acetate with (B) one or more kinds of water-insoluble vinyl compound selected from a 5-22Cα-olefin, a 5-22C alkylvinyl ether, a 5-22Cα,β-unsaturated carboxylic acid amide, a 5-22Cα-branchedα,β-unsaturated carboxylic acid ester and a 5-22Cα-branched saturated carboxylic acid vinyl ester as constituent units and then, saponifying the vinyl acetate unit part as an active ingredient in a paper pulp producing process. This pitch controlling method is characterized by adding the pitch controlling agent to pulp slurry or spraying the pitch controlling agent as water solution into papermaking processed apparatuses to which pitch is attached.
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