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:
May. 23, 2023

Filed:

Jul. 10, 2019
Applicant:

Kemira Oyj, Helsinki, FI;

Inventors:

Matti Hietaniemi, Espoo, FI;

Asko Karppi, Espoo, FI;

Jukka Rautiainen, Espoo, FI;

Assignee:

Kemira Oyj, Helsinki, FI;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
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);
U.S. Cl.
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);
Abstract

A method for manufacturing a multi-layered fibrous web is disclosed, which includes at least two fibrous layers, where 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. At least one layer of the multi-layered fibrous web is formed from a fibre stock including at least 50 weight-% of a chemi-thermomechanical pulp (CTMP), a hardwood kraft pulp and/or a recycled fibre material calculated from a thick stock applied to a particular layer approach system. A first strength component and a second strength component are added to the fibre stock. The first strength component includes a cationic strength agent and the second strength component includes a synthetic amphoteric polymer composition having a net charge from −3 to +1 meq/g (dry), at a pH of 7.


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