US 11,655,593 B2
Method for manufacturing multi-layered fibrous web and multi-layered fibrous web
Matti Hietaniemi, Espoo (FI); Asko Karppi, Espoo (FI); and Jukka Rautiainen, Espoo (FI)
Assigned to Kemira Oyj, Helsinki (FI)
Appl. No. 17/252,295
Filed by Kemira Oyj, Helsinki (FI)
PCT Filed Jul. 10, 2019, PCT No. PCT/FI2019/050540
§ 371(c)(1), (2) Date Dec. 15, 2020,
PCT Pub. No. WO2020/012074, PCT Pub. Date Jan. 16, 2020.
Claims priority of application No. 20185639 (FI), filed on Jul. 12, 2018.
Prior Publication US 2021/0262169 A1, Aug. 26, 2021
Int. Cl. D21H 11/08 (2006.01); D21H 11/14 (2006.01); D21H 17/29 (2006.01); D21H 17/37 (2006.01); D21H 17/55 (2006.01); D21H 27/00 (2006.01); D21H 27/10 (2006.01); D21H 27/30 (2006.01)
CPC D21H 11/08 (2013.01) [D21H 11/14 (2013.01); D21H 17/29 (2013.01); D21H 17/375 (2013.01); D21H 17/55 (2013.01); D21H 27/005 (2013.01); D21H 27/10 (2013.01); D21H 27/30 (2013.01)] 18 Claims
1. A method for manufacturing a multi-layered fibrous web, which comprises at least two fibrous layers, wherein each layer is formed from one or more fibre stocks, the fibrous layers are combined prior to subjecting the multilayered fibrous web to wet-pressing and drying, said method comprising:
forming at least one layer of the multi-layered fibrous web from a fibre stock comprising at least 50 weight-% of a chemi-thermomechanical pulp (CTMP), a hardwood kraft pulp and/or a recycled fibre material calculated from solid contents of a thick stock applied to a particular layer approach system; and
adding a first strength component and a second strength component to the fibre stock,
wherein the first strength component comprises a cationic strength agent and the second strength component comprises a synthetic amphoteric polymer composition having a net charge from −3 to +1 meq/g (dry), at a pH of 7.