THERMALLY MODIFIED WOOD PRODUCT AND A PROCESS FOR PRODUCING SAID PRODUCT

• US 20190329442A1
• Filed: 06/14/2017
• Published: 10/31/2019
• Est. Priority Date: 06/15/2016
• Status: Abandoned Application

• Current Assignee: Stora Enso Oyj
• Original Assignee: Stora Enso Oyj
• Inventors: Kallander, Bjorn
• Application Number:
  US16/310,159
• Publication Number:
  US 20190329442A1
• Time in Patent Office: Days
• CPC Class Codes: B27K 3/0214 Drying drying in general F26B
• CPC Class Codes: B27K 5/0085 Thermal treatments, i.e. involving chemical modification of wood at temperatures well over 100°C
• CPC Class Codes: B27K 5/009 using a well-defined temperature schedule
• CPC Class Codes: F26B 2210/16 Wood, e.g. lumber, timber
• CPC Class Codes: F26B 5/04 by evaporation or sublimation of moisture under reduced pressure, e.g. in a vacuum F26B11/049 and F26B17/128 take precedence

Abstract

The present invention relates to a process for preparing a modified wood product. More specifically, the invention relates to a method of performing thermal modification, wherein the thermally modified wood is suitable for load bearing use. The present invention also relates to a modified wood product produced using said process.

Claims

1. Thermally modified solid wood which is suitable for load bearing purposes.

2. Thermally modified solid wood according to claim 1, having a characteristic bending strength of at least 18 N/mm².

3. Thermally modified solid wood according to claim 2, wherein the bending strength is measured according to EN408:

2010.

4. Thermally modified solid wood according to claim 1, which is suitable for load bearing purposes above ground.

5. Thermally modified solid wood according to claim 4, wherein the suitability for use above ground is defined in accordance with Use Class 3.1 as described in the European standard EN335:

2013.

6. Thermally modified solid wood according to claim 1, wherein said wood is pine wood or spruce wood.

7. Process for preparing thermally modified solid wood, wherein wood is dried to an average moisture content of less than 5% at an average wood temperature of less than 100°

C., followed by an increase in wood temperature to above 140°

C.

8. Process according to claim 7, wherein the wood is dried to an average moisture content of less than 5% at an average wood temperature of less than 100°

C., followed by an increase in wood temperature to above 160°

C. at atmospheric pressure, wherein the wood is maintained at a temperature above 160°

C. for at least one hour, followed by cooling to ambient temperature.

9. Process according to claim 8, wherein the wood is dried to an average moisture content of less than 5% at an average wood temperature of less than 100°

C., followed by an increase in wood temperature to a temperature above 160°

C. and below 250°

C. at atmospheric pressure, wherein the wood is maintained at a temperature above 160°

C. and below 250°

C. for at least one hour, followed by cooling to ambient temperature.

10. Process according to claim 7, wherein the wood is dried to an average moisture content of less than 5% at an average wood temperature of less than 100°

C., followed by an increase in wood temperature to above 120°

C. at a pressure higher than atmospheric pressure, wherein the wood is maintained at a temperature above 120°

C. for at least one hour, followed by cooling to ambient temperature.

11. Process according to claim 7, wherein the drying is performed at an absolute pressure below 1013 mBar.

12. Process according to claim 7, wherein the drying is performed at an absolute pressure above 1013 mBar.

13. Process according to claim 7, wherein the drying is performed at an absolute pressure of approximately 1013 mBar.

14. Thermally modified solid wood obtainable by the process according to claim 7.