	US 11,834,792 B2
	Paper strength improvement using metal chelates and synthetic cationic polymers
Clayton Campbell, Atlanta, GA (US); Junhua Chen, Atlanta, GA (US); and Zheng Dang, Atlanta, GA (US)
Assigned to Kemira OYJ, Helsinki (FI)
Appl. No. 17/599,797
Filed by KEMIRA OYJ, Helsinki (FI)
PCT Filed Apr. 1, 2020, PCT No. PCT/US2020/026066 § 371(c)(1), (2) Date Sep. 29, 2021, PCT Pub. No. WO2020/205907, PCT Pub. Date Oct. 8, 2020.
Claims priority of provisional application 62/828,009, filed on Apr. 2, 2019.
Claims priority of application No. 20195452 (FI), filed on May 29, 2019.
Prior Publication US 2022/0195672 A1, Jun. 23, 2022
Int. Cl. D21H 21/20 (2006.01); D21H 17/55 (2006.01); D21H 17/66 (2006.01); D21H 17/69 (2006.01); D21H 17/00 (2006.01); D21H 23/50 (2006.01)

CPC D21H 21/20 (2013.01) [D21H 17/55 (2013.01); D21H 17/66 (2013.01); D21H 17/69 (2013.01); D21H 17/74 (2013.01); D21H 23/50 (2013.01)]

15 Claims

1. A method for manufacturing paper with improved strength, comprising steps of:

providing a thick stock, being a cellulosic fiber suspension having a consistency of above 20 g/l;

diluting the thick stock with white water or other circulating water into a thin stock;

delivering the thin stock to a headbox;

draining the thin stock on a moving screen to form a wet web;

pressing and drying the wet web in a press section and a dryer section to form a dry sheet; wherein

the method further comprises:

adding a metal chelate and at least one synthetic cationic polymer to the thick stock, the thin stock, the wet web, or any combination thereof.