JPH0681685B2 - Method for producing acetylated wood - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing acetylated wood used as a wood material for construction or furniture.

[Prior Art] It has been conventionally known that acetylated wood can be produced by subjecting wood to gas phase treatment at 130 ° C. for 2 to 5 hours with acetic anhydride to proceed with the following reaction.

_{Wood-OH + (CH 3 CO} ) 2 O ↓ Wood-OCOCH 3 + CH 3 COOH The acetylated wood, weather resistance is excellent in dimensional stability and crack resistance, since acetic acid is produced as a by-product, the thickness It was difficult to remove this acetic acid or acetic acid odor in wood with a diameter of 2 mm or more. Therefore, in order to produce thick acetylated wood, a method of laminating thin acetylated wood has been adopted, which has a drawback that a lot of man-hours are required and the cost is high.

[Problems to be Solved by the Invention] The present invention is intended to prevent acetic acid and its odor from occurring in wood when the wood is acetylated.

[Means for Solving the Problem] The present invention relates to a method for producing acetylated wood, which comprises reacting wood with a ketene monomer under a pressure atmosphere after vacuum drying, and is represented by the following reaction formula. Be done.

Wood-OH + CH ₂ CO ↓ Wood-OCOCH ₃ This invention will be described in more detail.

The wood cut to an appropriate size is vacuum-dried in a vacuum dryer at 30 to 200 ° C to remove air and moisture from the wood. Moisture in wood is removed because when water is present, ketene monomer (CH ₂ CO) is easily converted to acetic acid. Once the wood has been thoroughly dried and degassed, ketene monomer is then fed into the device and pressurized to 5-20 atmospheres. Ketene monomer is acetone, acetic acid or ketene dimer 500 ~ 8
Manufactured by decomposition in a furnace at 00 ℃.

The above reaction has an acetylation amount of 10 to 50%, preferably 15 to 35%.
React until it reaches%. The reaction temperature at this time is 80-140
C. and the reaction time are preferably 30 minutes to 5 hours, but are not limited thereto. After the reaction is completed, the ketene gas remaining in the apparatus is introduced into water and converted into acetic acid and taken out.

EFFECTS OF THE INVENTION Since the present invention is configured as described above, thick acetylated wood can be easily obtained without acetic acid or acetic acid odor in the produced acetylated wood.

[Example 1] A white ash material having a thickness of 15 mm, a width of 150 mm and a length of 300 mm was used.
After drying in a vacuum dryer at 100 ° C. for 5 hours, ketene gas produced by decomposing the ketene dimer in a furnace at 600 ° C. is introduced into this apparatus and pressurized to 10 atm. Then at 100 ℃ 2
After reacting for a time, the remaining excess ketene gas was introduced into water to turn it into acetic acid, and then the white ash material was taken out from the inside of the apparatus.

ASE of this thing is about 80%, 100 by weather meter
It passed the 0-hour weather resistance test, the cold heat repeated test (repetition of 80 ° C to 20 ° C) and the water absorption heating repeated test.

ASE = {(V _C −V _T ) / V _C } × 100 (Anti-swelling rate) V _C … Volume swelling rate of untreated material V _T … Volume swelling rate of treated material [Example 2] Same as Example 1 After the white ash material was vacuum dried, a predetermined amount of an acetone solution in which ketene gas was dissolved was put into this apparatus, and the pressure was immediately returned to normal pressure, and then the pressure was increased to 12 atm and left for 12 hours. Then, this was taken out, the solvent was scattered, and then heated at 100 to 120 ° C. for 3 hours to obtain acetylated wood.

The ASE of this product was about 70%, which was sufficient to pass the same test as the example.

Claims (1)

[Claims] 1. A method for producing acetylated wood, which comprises reacting wood with a ketene monomer under a pressure atmosphere after vacuum drying.