Coloration of acetylated wood

Patent metadata

Field	Value
Publication number	US-10315332-B2
Application number	US-201715809970-A
Country	US
Kind code	B2
Filing date	Nov 10, 2017
Priority date	Dec 8, 2016
Publication date	Jun 11, 2019
Grant date	Jun 11, 2019

Abstract

Techniques and products are described for coloring acetylated wood products. An acetylated wood product can be impregnated by a coloring medium within a chamber and the colorant or colorants contained within the coloring medium can be fixed to the acetylated wood product by the application of heat or by application of radio frequency radiation to color any external surface or interior region of the acetylated wood product which has been impregnated by the coloring medium.

First claim

I claim:

1. A method for coloring an acetylated wood product, comprising:
providing the acetylated wood product in a chamber;
providing a coloring medium including one or more colorants into the chamber;
causing the coloring medium to impregnate the acetylated wood product, causing the coloring medium to impregnate the acetylated wood product including controlling the degree of penetration of the coloring medium into the acetylated wood product by applying positive pressure after providing the coloring medium into the chamber without prior application of vacuum;
and heating the impregnated acetylated wood product to fix the one or more colorants to an exterior surface or an interior region of the acetylated wood product which has been impregnated by the coloring medium.

2. The method of claim 1 , further comprising:
reducing pressure in the chamber to remove at least some of the air from the acetylated wood product, wherein the coloring medium impregnates the surface and at least some of the interior of the acetylated wood product by replacing the air removed from the acetylated wood product by vacuum impregnation.

3. The method of claim 2 , further comprising:
applying positive pressure following the vacuum impregnation to further promote penetration of the coloring medium into the acetylated wood product.

4. The method of claim 1 , further comprising
without application of vacuum or positive pressure, immersing the acetylated wood product in the coloring medium to effect impregnation by infusion thereby limiting the impregnation to the surface so that, after fixation of the one or more colorants, the acetylated wood product is colored on its exterior surfaces.

5. The method of claim 1 , wherein heating the impregnated acetylated wood product effects fixation of the one or more colorants contained within the coloring medium which has impregnated the acetylated wood product.

6. The method of claim 5 , wherein the temperature is greater than 90 degrees Celsius (° C.).

7. The method of claim 1 wherein the heat energy required to fix the colorants to the impregnated acetylated wood product is provided by the use of irradiative techniques including one or more of: radio frequency waves, microwaves, or ultrasonic waves.

8. The method of claim 1 , wherein the one or more colorants includes one or more of inorganic pigments, organic pigments, disperse dyes, vat dyes, solvent dyes, or sulfur dyes.

9. The method of claim 1 wherein the liquid medium used to prepare the coloring medium includes water.

10. The method of claim 1 wherein the liquid medium used to prepare the coloring medium is comprised of at least 80% water.

11. The method of claim 1 , further comprising:
drying the acetylated wood product after fixation of the one or more colorants, wherein those exterior surfaces and interior regions of the acetylated wood product which were impregnated by the coloring medium remain colored after drying.

12. The method of claim 1 , wherein the coloring medium penetrates into the acetylated wood product, and further comprising:
replacing some or all of the coloring medium that did not penetrate into the acetylated wood product with a liquid medium including water, wherein the liquid medium is heated or pre-heated to fix the one or more colorants included in the coloring medium to those external surfaces and internal regions of the acetylated wood product impregnated by the coloring medium.

13. The method of claim 10 , wherein the liquid medium is comprised of at least 80% water.

14. The method of claim 1 , wherein the coloring medium penetrates into the acetylated wood product and further comprising:
removing from the chamber most of the coloring medium that did not penetrate into the acetylated wood product and introduction of steam or hot air or hot inert gas to fix the one or more colorants included in the coloring medium to those exterior surfaces and interior regions of the acetylated wood product impregnated by the coloring medium.

15. The method of claim 1 , wherein particles of the one or more colorants included in the coloring medium have diameters between 0.001 micrometers (microns) to 25 micrometers.

16. The method of claim 1 , wherein particles the one or more colorants included in the coloring medium have diameters between 0.001 micrometers (microns) to 5 micrometers.

17. An acetylated wood product prepared in accordance with the process of claim 1 in which either only the external surfaces or both the external surfaces and at least part of the interior regions are colored.

18. An acetylated wood product prepared in accordance with the process of claim 1 , wherein hue and intensity of the color conferred to the acetylated wood product is based on a chemical constitution of the colorant or blend of colorants applied and on a concentration of the colorant included in the coloring medium with the amount of coloring medium contained within the acetylated wood product after impregnation.

19. The acetylated wood product of claim 17 , the process further comprising: reducing pressure in the chamber to remove at least some of the air from the acetylated wood product, wherein the coloring medium impregnates the surface and at least some of the interior of the acetylated wood product by replacing the air removed from the acetylated wood product by vacuum impregnation.

20. The acetylated wood product of claim 17 , the process further comprising:
applying positive pressure following the vacuum impregnation to further promote penetration of the coloring medium into the acetylated wood product.

21. The acetylated wood product of claim 17 , the process further comprising:
controlling the degree of penetration of the coloring medium into the acetylated wood product by applying positive pressure after providing the coloring medium into the chamber without application of vacuum.

22. The acetylated wood product of claim 17 , the process further comprising:
without application of vacuum or positive pressure, immersing the acetylated wood product in the coloring medium to effect impregnation by infusion thereby limiting the impregnation to the surface so that, after fixation of the one or more colorants, the acetylated wood product is colored on its exterior surfaces.

23. The acetylated wood product of claim 17 , wherein heating the impregnated acetylated wood product effects fixation of the one or more colorants to the acetylated wood product.

24. The acetylated wood product of claim 23 , wherein the temperature is greater than 90 degrees Celsius (° C.).

25. The acetylated wood product of claim 17 , wherein the heat energy required to fix the colorants to the impregnated acetylated wood product is provided by the use of irradiative techniques including one or more of: radiofrequency radiation, microwaves, or ultrasonic waves.

26. The acetylated wood product of claim 17 , wherein the one or more colorants includes one or more of inorganic pigments, organic pigments, disperse dyes, vat dyes, solvent dyes, or sulfur dyes.

27. The acetylated wood product of claim 17 wherein the liquid medium used to prepare the coloring medium includes water.

28. The acetylated wood product of claim 17 wherein the liquid medium used to prepare the coloring medium is comprised of at least 80% water.

29. The acetylated wood product of claim 17 , the process

Assignees

• Electronics For Imaging Inc

Inventors

• Williams David J

Classifications

• B27K3/005

  employing compositions comprising microparticles · CPC title

• B27K5/003

  by using electromagnetic radiation or mechanical waves (infrared heating of wood B27K5/001) · CPC title

• B27K3/0292

  for improving fixation (B27K3/0285 takes precedence) · CPC title

• B27K5/0085

  Thermal treatments, i.e. involving chemical modification of wood at temperatures well over 100°C · CPC title

• B27K5/02 Primary

  Staining or dyeing wood {(wood staining compositions C09D15/00)}; Bleaching wood (bleaching wood pulp D21C9/10) · CPC title