US 12,134,860 B2
Method for manufacturing paper and cardboard
Cyril Barriere, Andrezieux Boutheon (FR)
Assigned to SNF GROUP, Andrezieux Boutheon (FR)
Appl. No. 18/691,353
Filed by SNF Group, Andrezieux Boutheon (FR)
PCT Filed Sep. 21, 2022, PCT No. PCT/EP2022/076265
§ 371(c)(1), (2) Date Mar. 12, 2024,
PCT Pub. No. WO2023/046774, PCT Pub. Date Mar. 30, 2023.
Claims priority of application No. 2110164 (FR), filed on Sep. 27, 2021.
Prior Publication US 2024/0263398 A1, Aug. 8, 2024
Int. Cl. D21H 17/46 (2006.01); D21H 23/18 (2006.01)
CPC D21H 17/46 (2013.01) [D21H 23/18 (2013.01)] 20 Claims
 
1. A process for manufacturing a paper or cardboard sheet from a fibrous suspension, comprising the following steps:
a) injecting a P3 polymer into a fibrous suspension,
b) forming a paper or cardboard sheet,
c) drying the paper or cardboard sheet,
polymer P3 being prepared before step a) from a water-soluble polymer P1 of at least one nonionic monomer selected from acrylamide, methacrylamide, N,N-dimethylacrylamide, and acrylonitrile,
polymer P1 being subjected to an Re1 reaction to give a polymer P2, which is then subjected to an Re2 reaction to give a P3 polymer, which is injected into the fibrous suspension within 24 hours from the start of the Re1 reaction,
wherein the Re1 reaction comprises preparing a P2 polymer comprising isocyanate functions by reaction for 10 seconds to 60 minutes between (i) an alkali hydroxide and/or an alkaline earth hydroxide, (ii) an alkali metal hypohalite and/or an alkaline earth metal hypohalite, and (iii) the P1 polymer,
wherein the Re2 reaction comprises preparing a P3 polymer by reaction between (iv) a micro-cellulose compound and (v) the P2 polymer comprising isocyanate functions.