The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Aug. 06, 2019

Filed:

Mar. 11, 2015
Applicants:

Kurita Water Industries Ltd., Tokyo, JP;

The Nippon Synthetic Chemical Industry Co., Ltd., Osaka-shi, Osaka, JP;

Inventors:

Chigusa Taguchi, Tokyo, JP;

Munetoshi Tomita, Osaka, JP;

Hiroki Takeda, Osaka, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
D21C 9/08 (2006.01); D21B 1/32 (2006.01); D21H 11/14 (2006.01); D21H 21/02 (2006.01); D21H 17/36 (2006.01); D21C 5/02 (2006.01);
U.S. Cl.
CPC ...
D21C 9/086 (2013.01); D21B 1/32 (2013.01); D21B 1/325 (2013.01); D21C 5/025 (2013.01); D21C 5/027 (2013.01); D21C 9/08 (2013.01); D21H 11/14 (2013.01); D21H 17/36 (2013.01); D21H 21/02 (2013.01); Y02W 30/648 (2015.05);
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:=−0.0297  (A)


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