Granted Patent B2

US 12,366,036 · App. 18/042,120 · Granted Jul 22, 2025

Inventors: Anna Kauppi (Lappeenranta, FI); Isto Heiskanen (Imatra, FI); Kaj Backfolk (Lappeenranta, FI); Jukka Kankkunen (Imatra, FI); Mikael Hjerpe (Karlstad, SE); Juha Korvenniemi (Oriniemi, FI)

Assignee: Stora Enso OYJ

D21H11/18D21F1/02D21F1/10D21F1/20D21F1/74D21F11/02D21H27/30

Abstract

Claims (25)

1. A method for manufacturing a film comprising highly refined cellulose fibers in a paper-making machine, the method comprising the steps of

a) providing an aqueous pulp suspension comprising at least 20%, by dry weight, of highly refined cellulose fibers having an SR (Schopper-Riegler) value in a range of 80-100 at a consistency in a range of 0.8-3 wt %

b) deflocculating and diluting the aqueous pulp suspension to a lower consistency in a range of 0.1-1.5 wt % by injecting the aqueous pulp suspension into an aqueous stream using a high shear mixer to obtain a diluted aqueous pulp suspension; and

c) feeding the diluted aqueous pulp suspension to a headbox of a paper-making machine;

d) forming a wet web by applying the diluted pulp suspension from the headbox onto a moving wire; and

e) dewatering the wet web to obtain a film comprising the highly refined cellulose fibers.

2. The method according to claim 1 , wherein the highly refined cellulose fibers of the pulp suspension provided in step a) have an SR value in a range of 80-98.

3. The method according to claim 1 , wherein the highly refined cellulose fibers comprise microfibrillated cellulose (MFC).

4. The method according to claim 1 , wherein the highly refined cellulose fibers comprise native highly refined cellulose fibers.

5. The method according to claim 1 , wherein the diluted pulp suspension flow speed between the high shear mixer and the headbox does not fall below 2.5 m/s.

6. The method according to claim 1 , wherein the aqueous stream in step b) comprises less than 0.1 wt % of highly refined cellulose fibers, or is free from highly refined cellulose fibers.

7. The method according to claim 1 , wherein the consistency of the aqueous pulp suspension provided in step a) is in a range of 1-2.5 wt %.

8. The method according to claim 1 , wherein the consistency of the diluted aqueous pulp suspension obtained in step b) is in a range of 0.1-1.2 wt %.

9. The method according to claim 1 , wherein the aqueous pulp suspension in step b) is injected into the aqueous stream at a flow speed in of at least 10 m/s.

10. The method according to claim 1 , wherein the high shear mixer is a static mixer.

11. The method according to claim 1 , wherein the wire is subjected to shaking during forming in step d) and dewatering in step e).

12. The method according to claim 1 , wherein step e) comprises:

dewatering and drying the web to obtain a film comprising the highly refined cellulose fiber.

13. The method according to claim 1 , further wherein step e) comprises:

partially dewatering the wet web to obtain a partially dewatered wet web;

laminating the partially dewatered wet web with a second partially dewatered wet web to form a multilayer web; and

dewatering the multilayer web to obtain the film.

14. The method according to claim 13 , wherein the wire is subjected to shaking during forming in step d) and dewatering in step e).

15. The method according to claim 13 , wherein step e) further comprises:

dewatering and drying the multilayer web to obtain a film comprising the highly refined cellulose fiber.

Assignments (1)

Priority Claims (1)

Continuity (1)

References Cited (49)