Printing paper without ink

Patent metadata

Field	Value
Publication number	US-10639920-B2
Application number	US-201615762141-A
Country	US
Kind code	B2
Filing date	Sep 23, 2016
Priority date	Sep 23, 2015
Publication date	May 5, 2020
Grant date	May 5, 2020

Abstract

A method for printing a wet web material comprising microfibrillated cellulose, wherein said method comprises the steps of providing an aqueous suspension comprising microfibrillated cellulose; applying said aqueous suspension to a substrate, thus forming a wet web having a moisture content in the range of 5 to 70 weight-%; wherein the method further comprises the step of treating said wet web by heating at least one well-defined portion thereof, whereby the web is provided with a print at the at least one heated portion.

First claim

The invention claimed is:

1. A method for printing a wet web material comprising microfibrillated cellulose, wherein said method comprises the steps of:
providing an aqueous suspension comprising microfibrillated cellulose;
applying said aqueous suspension to a substrate, thus forming a wet web having a moisture content in the range of 5 to 70 weight-%;
wherein the method further comprises the steps of:
treating said wet web by heating at least one well-defined portion thereof, whereby the web is provided with a print at the at least one heated portion; and,
de-watering or drying the web, wherein the dried web has a density of 400-1500 kg/m 3 .

2. The method as claimed in claim 1 , wherein the dried web has a basis weight of less than 60 gsm.

3. The method as claimed in claim 1 wherein the substrate is a porous wire of a papermaking machine.

4. The method as claimed in claim 1 , wherein the well defined portions comprises at least one of a figure and a letter.

5. The method as claimed in claim 1 , wherein the heating is performed by using laser.

6. The method as claimed in claim 1 , wherein the suspension comprises microfibrillated cellulose in an amount of 60-100 wt-% based on total dry solid content.

7. The method as claimed in claim 1 , wherein the moisture content in the wet web is in the range of from 10 to 60 weight-%.

8. The method as claimed in claim 1 , wherein the step of heating is performed in an in-line process step.

9. The method as claimed in claim 1 , wherein the step of heating is performed in an off-line process step.

10. The method as claimed in claim 1 , wherein the method further comprises a step of at least one of treating the surface of the web and coating the web.

11. The method as claimed in claim 1 , wherein the moisture content in the wet web is in the range of from 20 to 50 weight-%.

12. The method as claimed in claim 1 , wherein the moisture content in the wet web is in the range of from 25 to 45 weight-%.

13. A paper or paper product, comprising a web, obtained by the method of claim 1 .

14. A method for printing a wet web material comprising microfibrillated cellulose, wherein said method comprises the steps of:
providing an aqueous suspension comprising microfibrillated cellulose, wherein the suspension comprises microfibrillated cellulose in an amount of 60-100 wt-% based on total dry solid content;
applying said aqueous suspension to a substrate, thus forming a wet web having a moisture content in the range of 5 to 70 weight-%; and,
treating said wet web by heating at least one well-defined portion thereof, whereby the web is provided with a print at the at least one heated portion.

Assignees

• Stora Enso Oyj

Inventors

• Miikki Nina

Classifications

• D21H25/04

  Physical treatment, e.g. heating, irradiating (D21H25/18 takes precedence; dryer section of machines for making continuous webs of paper D21F5/00) · CPC title

• B41M3/10

  Watermarks · CPC title

• B41M5/0035 Primary

  Uncoated paper (paper making D21) · CPC title

• D21F11/006

  Making patterned paper · CPC title

• D21H11/18

  Highly hydrated, swollen or fibrillatable fibres · CPC title