Flexible microfibrillated film formation

Patent metadata

Field	Value
Publication number	US-10501890-B2
Application number	US-201615754692-A
Country	US
Kind code	B2
Filing date	Sep 16, 2016
Priority date	Sep 17, 2015
Publication date	Dec 10, 2019
Grant date	Dec 10, 2019

Abstract

A method of manufacturing a film comprising microfibrillated cellulose, wherein the method comprises the steps of: providing a first suspension comprising microfibrillated cellulose, having a dry content of from 0.2 to 2.0%, wherein the first suspension has a first Schopper-Riegler (SR) value; forming a first web of said suspension; at least partly dewatering said first web; applying a second suspension comprising microfibrillated cellulose, and/or fines and/or fibers onto a surface of said formed and at least partially dried first web, wherein the second suspension has a second Schopper-Riegler value which is higher than said first Schopper-Riegler value, thereby forming a film.

First claim

The invention claimed is:

1. A method of manufacturing a film comprising microfibrillated cellulose, wherein the method comprises the steps of:
providing a first suspension comprising microfibrillated cellulose in an amount of at least 50 weight % based on the total weight of solids of the suspension, having a dry content of from 0.2 to 2.0%, wherein the first suspension has a first Schopper-Riegler (SR) value;
forming a first web of said suspension;
at least partly dewatering said first web;
applying a second suspension comprising microfibrillated cellulose onto a surface of said formed and at least partially dewatered first web, wherein the second suspension has a second Schopper-Riegler value which is higher than said first Schopper-Riegler value; and,
forming a film after the second suspension has been applied to said formed and at least partially dewatered first web.

2. The method as claimed in claim 1 , wherein said first suspension further comprises a filler material in an amount of from 3 to 40 weight %, based on the total weight of solids of the suspension.

3. The method as claimed in claim 1 , wherein said first suspension further comprises fibers in an amount from 5-50 weight %, based on the total weight of solids of the suspension.

4. The method as claimed in claim 1 , wherein said first suspension has a SR value in the range of from 40 to 90.

5. The method as claimed in claim 1 , wherein said second suspension further comprises at least one from a group consisting of: fines, fibers, fillers materials, retention chemicals, flocculation additives, deflocculating additives, wet strength chemicals, dry strength additives, softeners, or mixtures thereof.

6. The method as claimed in claim 1 , wherein said second suspension is provided to the surface of the first web in a head-box.

7. The method as claimed in claim 1 , wherein said second suspension is provided to the surface of the first web by a size press.

8. The method as claimed in claim 1 , wherein said second SR value is from 5% to 30% higher than said first SR value.

9. The method as claimed in claim 1 , wherein said second suspension has less dry content than the first suspension.

10. The method as claimed in claim 1 , wherein said second suspension is applied to the surface of the first web in the form of foam.

11. The method as claimed in claim 1 , wherein the method further comprises the step of dewatering the formed film.

12. The method as claimed in claim 11 , wherein the dewatering is performed by vacuum.

13. The method as claimed claim 11 , wherein the dewatering is performed by mechanical pressure.

14. A film obtained by the method as claimed in claim 1 , wherein the film has an oxygen transmission rate (OTR) of less than 500 ml/m 2 /24 h.

15. A film obtained by the method as claimed in claim 1 , wherein the film has a basis weight of less than 50 g/m 2 .

16. The method as claimed in claim 1 , wherein said first suspension further comprises a filler material in an amount of from 5 to 15 weight %, based on the total weight of solids of the suspension.

17. The method as claimed in claim 1 , wherein said first suspension further comprises long fibers in an amount of from 5 to 15 weight %, based on the total weight of solids of the suspension.

18. The method as claimed in claim 1 , wherein said first suspension has a SR value in the range of from 60 to 85.

19. A film obtained by the method as claimed in claim 1 , wherein the film has an oxygen transmission rate (OTR) of less than 50 ml/m 2 /24 h.

20. A film obtained by the method as claimed in claim 1 , wherein the film has an oxygen transmission rate (OTR) of less than 1 ml/m 2 /24 h.

21. A film obtained by the method as claimed in claim 1 , wherein the film has a basis weight of less than 35 g/m 2 .

22. A film obtained by the method as claimed in claim 1 , wherein the film has a basis weight of less than 20 g/m 2 .

Assignees

• Stora Enso Oyj

Inventors

• Heiskanen Isto
• Backfolk Kaj
• Lyytikainen Katja

Classifications

• D21H27/30

  Multi-ply (for surface covering D21H27/18; making on paper-making machines D21F9/00, D21F11/00) · CPC title

• D21F1/66

  Pulp catching, de-watering, or recovering; Re-use of pulp-water · CPC title

• D21H11/18 Primary

  Highly hydrated, swollen or fibrillatable fibres · CPC title

• D21H19/52

  Cellulose; Derivatives thereof · CPC title

• D21H19/34

  comprising cellulose or derivatives thereof · CPC title