Coated wood veneer and method for treating wood veneer

Patent metadata

Field	Value
Publication number	US-11931774-B2
Application number	US-201916963878-A
Country	US
Kind code	B2
Filing date	Jan 16, 2019
Priority date	Jan 23, 2018
Publication date	Mar 19, 2024
Grant date	Mar 19, 2024

Abstract

Disclosed is a method for treating wood veneer, including the steps of providing at least one sheet of wood veneer; coating at least one side of the sheet of wood veneer with an aqueous coating composition including nanocellulose to obtain a coated sheet of wood veneer; and drying the coated sheet using compression pressure and heat. Also disclosed is a coated wood veneer including a sheet of wood veneer and a coating including nanocellulose arranged on at least one surface of the sheet.

First claim

The invention claimed is:

1. A method for treating wood veneer, the method comprising:
providing at least one sheet of wood veneer;
coating at least one side of the at least one sheet of wood veneer with an aqueous coating composition comprising nanocellulose in an amount between 4 to 18% by weight, calculated of the weight of the total coating composition, the nanocellulose having apparent viscosity between 8,000 and 22,000 mPa·s after the aqueous coating composition comprising the nanocellulose is mixed for about 10 minutes at about 300 rpm and then mixed for about 2 minutes at 14,000 rpm, in a consistency of 5% by weight at a temperature of 20 ° C. to obtain a coated sheet of wood veneer; and
drying the coated sheet using compression pressure and heat.

2. The method according to claim 1 , wherein the aqueous coating composition is applied on the sheet of wood veneer in an amount between 2 and 100 g/m 2 , measured as the amount of dry coating composition.

3. The method according to claim 1 , wherein the nanocellulose has apparent viscosity between 10,000 and 20,000 mPa·s.

4. The method according to claim 1 , wherein the nanocellulose is enzymatic nanocellulose.

5. The method according to claim 1 , wherein the nanocellulose comprises lignin at most 10% by weight of nanocellulose.

6. The method according to claim 1 , wherein the aqueous coating composition comprises water between 75 and 96% by weight of total coating composition.

7. The method according to claim 1 , wherein the aqueous coating composition comprises nanocellulose between 7 and 18% by weight of total coating composition.

8. The method according to claim 1 , wherein the aqueous coating composition comprises at least one additive selected from the group consisting of light absorbing additives, anti-mold agents, anti-microbial agents, fire-retarding agents, color agents, decorative components, surface active agents and combinations thereof.

9. The method according to claim 1 , wherein the wood veneer is rotary peeled wood veneer.

10. The method according to claim 1 , wherein the aqueous coating is applied only on a concave side of the wood veneer.

11. The method according to claim 1 , wherein the coating is performed using one of spray coating, film transfer coating, curtain coating, brush application, roller application, blade coating, and stripe application.

12. The method according to claim 1 , wherein a temperature in the drying is between 0 and 210 ° C.

13. The method according to claim 1 , wherein the compression pressure in the drying is between 20 and 500 kPa.

14. The method according to claim 1 , wherein the drying comprises:
arranging the sheet between a first belt assembly and a second belt assembly, the first belt assembly comprising a first metal belt, the second belt assembly comprising a second metal belt, at least one porous screen band or a porous surface section being disposed between the second metal belt and the wood veneer, the first metal belt being heated to a first temperature, the second metal belt being cooled to a second temperature that is lower than the first temperature,
pressing the first belt assembly and the second belt assembly towards each other during the heating and cooling whereupon the compression pressure is applied to the sheet between the first belt assembly and the second belt assembly from the first metal belt and the screen band or surface section,
allowing water separated from the sheet due to the effect of the first temperature to condense into the screen band or into the surface section due to the effect of the second temperature, and
removing the sheet that is dried from between the first belt assembly and the second belt assembly.

15. The method according to claim 14 , wherein the first temperature is from 120 to 210° C. and the second temperature is between 0 and 60° C.

16. The method according to claim 1 , wherein a tensile strength in cross direction of the wood veneer is 1.83 N/mm 2 .

Assignees

• Teknologian Tutkimuskeskus Vtt Oy
• Aalto Univ Foundation Sr

Inventors

• Pere Jaakko
• Kunnari Vesa
• Kairi Matti
• Ahtila Pekka

Classifications

• B05D7/10 Primary

  based on cellulose derivatives · CPC title

• C09D101/02

  Cellulose; Modified cellulose · CPC title

• B05D3/0254

  After-treatment · CPC title

• B05D2401/20

  Aqueous dispersion or solution · CPC title

• B05D7/06 Primary

  to wood · CPC title