JPS6135208A - Method of improving and treating woody material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for modifying wood materials.

(Prior art) Wood and its processed materials, such as wood veneers and wood chips, are light and strong, and have unique physical properties and material textures. It is used for a wide range of purposes, including construction materials and furniture materials.7 However, this wood material is subject to erosion by various fungi and insect damage such as termites, and rots and warps due to its breathability. It has the disadvantage of being susceptible to deformation such as expansion and contraction.

Therefore, in recent years, attempts have been made to acetylate wood materials in order to eliminate the above-mentioned drawbacks.

That is, a wood material is immersed in an acetylation reaction solution with IL2 to react, and then the wood material is taken out from the reaction solution, and the wood material is washed and dried to obtain an acetylated wood material.

(Problems to be Solved by the Invention) Incidentally, in the acetylation step described above, the reaction time required for acetylation is long, resulting in very poor productivity.

In this acetylation reaction, in order to shorten the reaction time and increase productivity, the reaction is carried out in a high-temperature reaction solution of 100°C or higher, but such treatment requires immersing the wood material in the high-temperature reaction solution for a long time. In order to do this, the wood components are extracted into the reaction solution,
This causes defects such as discoloration and deterioration of wood materials. For this reason,
Although it is necessary to shorten the immersion time of the wood material in the reaction solution, in this case there is a drawback that the acetylation rate is low.

(Problems to be Solved by the Invention) Therefore, the present invention involves heating a wood material injected and impregnated with an acetylation reaction solution in a reaction vessel in an atmosphere filled with organic solvent vapor that does not react with the reaction solution. A wood material modification treatment characterized by reacting a wood material and an acetylation reaction liquid injected into the wood material using the organic solvent vapor as a heating medium to acetylate the hydroxyl groups of the wood material components. It's a method.

(Function/Effect) As described above, in the present invention, the wooden material impregnated with the reaction solution is acetylated by heating in an atmosphere filled with organic solvent vapor that does not react with the reaction solution. ,
Since wood exists in high-pressure steam, there is no extraction of wood components, and therefore a high degree of acetylation can be achieved without causing discoloration or deterioration of the wood material. Further, even when the catalyst is impregnated into the wood material, the catalyst does not leak out.

(Example) Hereinafter, a method for modifying wood materials according to the present invention will be described.

Wooden materials to which the present invention is applied include wood and wood veneer.

When referring to wood chips or the like, if the thickness thereof is 3 mm or more, it is preferable to apply a catalyst treatment in advance to promote the acetylation reaction described below.

In this case, the catalyst is preferably an acetate aqueous solution, such as sodium acetate or potassium acetate, which does not deteriorate the wood material and can be easily removed by washing with water. 40° to do
It may be heated to 80° C. or impregnated with an acetate aqueous solution by vacuum injection, pressure injection, or vacuum pressure injection in a vacuum pressure cooker.

Note that the concentration of the acetate aqueous solution is not particularly limited, but is preferably 2 to 30%.

Next, the wooden material impregnated with the acetate aqueous solution is suitably dried, but preferably the moisture content of the wooden material is 0% or less.

A catalyst-containing wood material dried as described above, or
Inject the acetylation reaction solution into untreated wood.

In this case, the wood material may be simply immersed in the reaction solution, but the reaction solution may be injected into the interior of the wood material using a vacuum method, pressurization method, or vacuum pressure method in a vacuum pressure cooker (reaction container). Good too.

The reaction solution mainly consists of acetic anhydride, and 30%
% of acetic acid or aromatic hydrocarbons such as toluene, xylene, benzene, etc. may be used.

In this way, mixing an organic solvent with acetic anhydride reduces the amount of expensive acetic anhydride used, and
This is to improve the working environment by reducing the strong pungent odor of acetic anhydride, and to reduce the decrease in strength of wood materials caused by acetic anhydride.

Furthermore, before immersing the wood material in the reaction solution, it is desirable to vacuum the wood material under reduced pressure in advance to remove air from the wood material before immersing it in the reaction solution.

Then, impregnate with the reaction liquid as described above (70 to 200% by weight of the reaction liquid is impregnated with respect to the weight of the wood material).
The treated wood material is placed in a reaction pot, and an organic solvent that does not react with the reaction solution, such as toluene, is placed in the reaction pot.
The wood material is heated to about 120° C. for a predetermined time while being filled with xylene heated vapor, and the hydroxyl groups in the wood material are acetylated with the impregnating reaction liquid. In addition to the method of heating the organic solvent vapor and blowing it into the reaction vessel, it is also possible to supply the solvent liquid and heat it to vaporize it to fill it.

After the acetylation reaction is sufficiently carried out and a predetermined period of time has elapsed, the mixture is vacuumed and depressurized at a higher vacuum level than 1 (1 (1 + nmHg), for example, to lower the boiling point and vaporize a part of the reaction liquid in the wood material. It is collected from the reaction vessel together with exhaust air, liquefied in a condenser, and collected.When the reaction liquid is vaporized, the temperature of the wood material tends to decrease due to the latent heat of evaporation, but as mentioned above, Since the reaction vessel is heated, the temperature drop is small and the reaction liquid can be recovered efficiently. At this time, by continuing vacuum suction, all or most of the reaction liquid in the wood material can be recovered. It is also possible to do this, but it takes a long time, so
It seems good to recover 70% of the amount in terms of the number of times the device is used and the cost.

Note that the wood material may be immediately taken out from the reaction vessel and washed without suctioning and reducing the pressure.

Experimental Example 3 - A plow-thick rainbow pine veneer was impregnated with a 5% potassium acetate aqueous solution, dried, and the veneer to which 7.5% by weight of potassium acetate was added was charged into a reaction vessel, and 30 +n+n H
After degassing the inside of the container under reduced pressure for 5 minutes, a reaction solution consisting of 95% acetic anhydride and 5% by weight of acetic acid was poured into the reaction container under reduced pressure, and the mixture was poured into the veneer for 15 minutes. Inject the reaction solution. Next, the reduced pressure was released, and the reaction solution was once deliquified and then placed in a reaction pot. Xylene heated steam was continuously supplied and the wood material was maintained at 120°C, and the wood material was heated continuously for 30 minutes. The hydroxyl groups inside were allowed to react with the reaction solution.

After that, the inside of the reaction vessel was evacuated and depressurized by 50+oiHg, and the vaporized reaction liquid in the single plate was condensed by the condenser of the reaction liquid recovery device installed between the reaction vessel and the vacuum pump, and collected in the receiver, and the acetylation reaction was carried out. The resulting veneer was washed and dried, and the acetylation rate was measured to be 18%.

Patent applicant: Daiken Kogyo Co., Ltd. Representative: Patent attorney: Seihaku Bo, and 2 others (9 patents)

Claims (4)

[Claims] (1) In a reaction vessel, heat the wood material injected and impregnated with the reaction solution in an atmosphere filled with organic solvent vapor that does not react with the acetylation reaction solution, and heat the wood material and the acetyl injected into the wood material. A method for modifying a wood material, which comprises reacting the organic solvent vapor with the organic solvent vapor as a medium to acetylate the hydroxyl groups of the wood component. (2) The method for modifying wood materials according to claim 1, wherein the organic solvent is toluene or xylene. (3) The method for modifying a wood material according to claim 1, wherein the wood material is impregnated with an aqueous acetate catalyst solution and then dried. (4) The method for modifying wood materials according to claim 1, wherein the reaction liquid is a mixture of an organic solvent such as an aromatic hydrocarbon and acetic anhydride.