Method for producing paper, and pitch removal agent
AssigneesKurita Water Industries Ltd., Mitsubishi Chemical Corporation
InventorsChigusa Taguchi, Munetoshi Tomita, Hiroki Takeda
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Abstract
Provided is a method for producing paper and a pitch removal agent that can remove pitch efficiently. A pitch removal agent having an average polymerization degree of 300 to 2500, a saponification index of 70 to 88 mol % and satisfying, when the absorbance at a wavelength of 490 nm is designated as y (Abs) and the saponification index as x (mol %), the Numerical Formula (A) below is added to a pulp slurry during production of paper using waste paper in the step of deinking the waste paper by floatation and/or a step earlier: y=−0.0297x+b (A) (wherein, 70≤x≤88 and 2.80≤b≤3.03).
Claims5
A method for producing paper using waste paper, comprising:
- polymerizing a compound in a presence of at least one chain-transfer agent containing an aldehyde, thereby obtaining polyvinyl acetate;
- saponifying the polyvinyl acetate, thereby obtaining a polyvinyl alcohol;
- and
- adding, to a pulp slurry in a step of deinking the waste paper by floatation and/or a step earlier, the polyvinyl alcohol having an average polymerization degree of 300 to 2500, a saponification index of 70 to 88 mol %, and an absorbance at a wavelength of 280 nm in an ultraviolet absorption spectrum of its 0.1 mass % aqueous solution of 0.2-1.0 Abs and satisfying, when an iodine absorbance at a wavelength of 490 nm is designated as y (Abs) and the saponification index as x (mol %), the following Numerical Formula (A):
- [Numerical Formula 1]
- y=−0.0297x+b (A)
- (wherein, 70≤x≤88 and 2.80≤b≤3.03).
Dependencies are inferred from the claim text.