Patterned liquid repellent nanocellulosic film

Patent metadata

Field	Value
Publication number	US-12152115-B2
Application number	US-202017756985-A
Country	US
Kind code	B2
Filing date	Dec 22, 2020
Priority date	Dec 23, 2019
Publication date	Nov 26, 2024
Grant date	Nov 26, 2024

Abstract

A textured film is provided which comprises nanocellulose. At least a first surface of the film comprises a patterned, textured surface formed by repeating protruding regions and at least one non-protruding region arranged between said protruding regions. A particular height difference between the protruding and non-protruding regions can give liquid repellent properties. Methods for making the textured film are also provided.

First claim

The invention claimed is:

1. A method for manufacturing a textured film with a liquid repellant surface, said method comprising the steps of:
a. providing a textured belt or cylinder, the surface of said textured belt or cylinder comprising a repeating pattern of recessed regions and at least one non-recessed region arranged between said recessed regions, wherein each recessed region is recessed a depth d from an adjacent non-recessed region, said depth d being determined in a direction perpendicular to the surface of said textured belt, said depth d being between 1-100 μm;
b. cast forming an aqueous suspension comprising nanocellulose onto the surface of said textured belt comprising the repeating pattern; and dewatering said suspension to form a wet textured web comprising nanocellulose, wherein the aqueous suspension comprises at least 50 wt % nanocellulose, based on a total solids content of said aqueous suspension; and
c. drying said wet textured web, to provide the textured film, the textured film comprising the nanocellulose, wherein a nanocellulose content in the textured film is at least 50 wt % based on total solids content of the textured film, said textured film extending in a first plane and having opposing first and second surfaces, wherein at least said first surface comprises the liquid repellant surface with a repeating pattern of protruding regions and at least one non-protruding region arranged between said protruding regions, wherein each protruding region protrudes a height h from an adjacent non-protruding region, said height h being determined in a direction perpendicular to the plane of said textured film, said height h being between 1-100 μm.

2. A method for manufacturing a textured film with a liquid repellant surface, said method comprising the steps of
a. casting or wet-laying an aqueous suspension comprising nanocellulose onto a substantially smooth dewatering surface, and dewatering said suspension to form a wet web comprising nanocellulose, wherein the aqueous suspension comprises at least 50 wt % nanocellulose, based on a total solids content of said aqueous suspension;
b. pressing said wet web comprising nanocellulose against a surface of a textured belt or cylinder, said surface of said textured belt or cylinder comprising a repeating pattern of recessed regions and at least one non-recessed region arranged between said recessed regions, wherein each recessed region is recessed a depth d from an adjacent non-recessed region, said depth d being determined in a direction perpendicular to the surface of said textured belt or cylinder, said depth d being between 1-100 μm, to provide a wet textured web comprising nanocellulose, wherein, during the pressing step, the wet web comprising nanocellulose is pressed against a permeable surface such as a nonwoven fabric, wire or membrane, and dewatered, and;
c. drying said wet textured web comprising nanocellulose to form the textured film, the textured film comprising the nanocellulose, wherein a nanocellulose content in the textured film is at least 50 wt % based on total solids content of the textured film, said textured film extending in a first plane and having opposing first and second surfaces, wherein at least said first surface comprises the liquid repellant surface with a repeating pattern of protruding regions and at least one non-protruding region arranged between said protruding regions, wherein each protruding region protrudes a height h from an adjacent non-protruding region, said height h being determined in a direction perpendicular to the plane of said textured film, said height h being between 1-100 μm.

3. The method according to claim 2 , wherein the pressure during step b. is between 0.5-100 MPa.

4. The method according to claim 2 , further comprising the step of:
coating the textured first surface, or said second surface of the textured film, or both with a surface treatment composition.

5. The method according to claim 1 , wherein the textured film comprises a grammage between 1-80 gsm.

6. The method according to claim 1 , wherein the textured film comprises a thickness between 5 to 200 μm.

7. The method according to claim 5 , wherein the textured film comprises a thickness between 5 to 200 μm.

Assignees

• Stora Enso Oyj

Inventors

• Backfolk Kaj
• Heiskanen Isto
• Miikki Nina

Classifications

• D21H19/34 Primary

  comprising cellulose or derivatives thereof · CPC title

• D21H11/18 Primary

  Highly hydrated, swollen or fibrillatable fibres · CPC title

• C08J2301/02

  Cellulose; Modified cellulose · CPC title

• B32B2553/00

  Packaging equipment or accessories not otherwise provided for · CPC title

• B32B2317/18

  Cellulose, modified cellulose or cellulose derivatives, e.g. viscose (B32B2317/10, B32B2317/12, B32B2317/16 take precedence) · CPC title