US 12,258,710 B2
Multilayer film comprising highly refined cellulose fibers
Isto Heiskanen, Imatra (FI); Kaj Backfolk, Lappeenranta (FI); Katja Lyytikäinen, Imatra (FI); and Jukka Kankkunen, Imatra (FI)
Assigned to Stora Enso OYJ, Helsinki (FI)
Appl. No. 17/995,446
Filed by Stora Enso OYJ, Helsinki (FI)
PCT Filed Apr. 14, 2021, PCT No. PCT/IB2021/053070
§ 371(c)(1), (2) Date Oct. 4, 2022,
PCT Pub. No. WO2021/209916, PCT Pub. Date Oct. 21, 2021.
Claims priority of application No. 2050423-9 (SE), filed on Apr. 15, 2020.
Prior Publication US 2023/0151545 A1, May 18, 2023
Int. Cl. D21F 11/04 (2006.01); B32B 3/26 (2006.01); B32B 5/02 (2006.01); B32B 5/26 (2006.01); B32B 7/12 (2006.01); B32B 37/12 (2006.01); D21H 11/18 (2006.01); D21H 19/34 (2006.01); D21H 23/24 (2006.01); D21H 23/48 (2006.01); D21H 23/50 (2006.01); D21H 27/36 (2006.01)
CPC D21F 11/04 (2013.01) [B32B 3/266 (2013.01); B32B 5/02 (2013.01); B32B 5/26 (2013.01); B32B 7/12 (2013.01); B32B 37/1284 (2013.01); D21H 11/18 (2013.01); D21H 19/34 (2013.01); D21H 23/24 (2013.01); D21H 23/48 (2013.01); D21H 23/50 (2013.01); D21H 27/36 (2013.01); B32B 2250/20 (2013.01); B32B 2250/40 (2013.01); B32B 2255/02 (2013.01); B32B 2255/26 (2013.01); B32B 2262/062 (2013.01); B32B 2307/412 (2013.01); B32B 2307/414 (2013.01); B32B 2307/718 (2013.01); B32B 2307/724 (2013.01)] 21 Claims
 
1. A method for manufacturing a multilayer film comprising highly refined cellulose fibers, the method comprising the steps of:
a) forming a first wet web by applying a first pulp suspension comprising highly refined cellulose fibers having a Schopper-Riegler (SR) value of 65 or higher, as determined by standard ISO 5267-1, on a first wire;
b) partially dewatering the first wet web to obtain a first partially dewatered web;
c) forming a second wet web by applying a second pulp suspension comprising highly refined cellulose fibers having a Schopper-Riegler (SR) value of 65 or higher, as determined by standard ISO 5267-1, on a second wire;
d) partially dewatering the second wet web to obtain a second partially dewatered web;
e) applying a binder between the first partially dewatered web and the second partially dewatered web by spray coating, curtain coating, or foam coating and joining the first partially dewatered web and the second partially dewatered web to obtain a multilayer web; and
f) further dewatering the multilayer web to obtain a multilayer film comprising highly refined cellulose fibers,
wherein a dry solids content of the first pulp suspension, the second pulp suspension, or both is in a range of 0.1-0.7 wt %.