JPS58181604A - Method of improving 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] Ru.

This example and its processed materials, such as wood veneer and wood chips, are light and strong, and have unique physical properties and textures, making them suitable for construction materials, furniture materials, and a wide range of other uses. It's being used.

However, on the other hand, it is easy to rot due to erosion by various fungi and insect damage such as termites, and in today's housing environment where airtightness is high and heating devices are popular, the occurrence of such rot is difficult. In fact, it has been increasing, and has become a major problem as one of the causes of decreased durability of wood materials.

In addition, while wood has the so-called breathability of absorbing and dissipating moisture depending on the surrounding environmental conditions, it can warp, twist, expand and contract due to repeated absorption and dissipation of moisture. It has the essential drawback of causing deformations such as.

To improve the above-mentioned rotting problems, use taleosote oil, etc.
A common method is to impregnate wood materials with preservatives and insect repellents, but this method has drawbacks such as a significant odor, which limits the areas where it can be used, and further increases the flammability of the wood materials.

Furthermore, it is known that it is effective to chemically modify the hydroxyl groups in the wood components by subjecting the wood material to a chemical treatment such as acetylation in order to improve the problems related to deformation.

However, since wood does not consist of a single component, but rather has a complex composition of components and a complex tissue structure, various methods have been used to perform the above-mentioned chemical HJ treatment on wood. It takes an extremely long time for one reaction, it is extremely difficult to remove excess reaction liquid and catalyst, and the strength properties of the wood H are significantly reduced, making it difficult to carry out in industrial production and impractical. There is a problem with the lack of time.

The present invention has been made in view of these problems, and includes impregnating a wooden material with an acylation catalyst consisting of an aqueous solution of a fatty acid salt.
After drying, the above-mentioned wood material is treated with fatty acid anhydride to acylate the hydroxyl groups in the wood components, thereby reducing the strength and properties of the wood material, which has a complex structure and composition. It is an object of the present invention to provide a method for modifying a wood material that can be efficiently modified into a wood material that has excellent rot resistance and less occurrence of deformation such as warping, twisting, expansion and contraction.

The method according to the present invention will be explained below.

The wood material used in the present invention refers to wood, wood veneer, wood chips, etc. First, the wood material is immersed in the catalyst by a method such as immersing the wood material in the above fatty acid salt aqueous solution. I can do it. In addition, in order to quickly impregnate,
A fatty acid aqueous solution heated to about 80° C. may be used, or a fatty acid salt aqueous solution may be injected under reduced pressure, injected under pressure, or impregnated through a pipe in the reduced pressure cooker.

As the fatty acid salt used here, sodium salts and potassium salts of fatty acids can be used.
= Acetate salts such as IJum and potassium acetate are suitable because they do not deteriorate wood materials, are easy to remove by washing with water, and can carry out the reaction described later well and quickly. be.

The concentration of the fatty acid salt aqueous solution is not particularly limited, and is preferably 5 to 30%.

Next, the wood material impregnated with the fatty acid salt aqueous solution is dried. Drying is performed to appropriately remove moisture in the wood, and may be performed using a drying device such as a dryer, so that the moisture content of the wood is 10% or less (this is done in the subsequent steps). It is particularly desirable for efficiently carrying out reactions using fatty acid anhydrides.

The dried catalyst-containing wood is subsequently treated with a fatty acid anhydride to react with the wood components, especially the hydroxyl groups of cellulose. The treatment of wood materials with fatty acid anhydrides can be carried out, for example, by immersing the wood materials in the fatty acid anhydride, or, similarly to the case of impregnating the wood materials with aqueous fatty acid salts, in a vacuum pressure cooker under reduced pressure. This may be carried out by injecting fat T17[2 anhydride into the interior of the wood material under pressure, pressure, or vacuum pressure.

As the fatty acid anhydride, it is economical and practically desirable to use lower fatty acid anhydrides such as acetic anhydride and propionic anhydride. Further, it is desirable that the fatty acid anhydride is heated to accelerate the reaction with the wood component, and in particular, the reaction rate can be significantly increased by using a fatty acid anhydride that has been heated to 100° C. or higher.

Therefore, in the method of the present invention, since the wooden material is impregnated with a fatty acid salt as an aqueous solution, the fatty acid salt adheres uniformly and efficiently to the wood, and water is removed by drying, so that the fatty acid salt can be absorbed into the wood. The fat 117J aqueous anhydride infiltrated into the wood can react well with the eight wood components.

In particular, drying once the aqueous fatty acid salt solution is impregnated is effective in minimizing the possibility that the fatty acid anhydride that has penetrated into the wood reacts with the moisture in the wood and converts into fatty acids. In other words, if the fatty acid anhydride is converted to a fatty acid regardless of the reaction with the hydroxyl group in the wood component, the efficiency with which the fatty acid contributes to the reaction of the fatty acid anhydride will decrease because the fatty acid will hardly react with the wood component. , it is possible to prevent such a significant decrease in reaction efficiency.

In addition, when such fatty acids, especially lower fatty acids such as acetic acid, are present in large quantities in the reaction system, they enter the crystalline region of wood components, especially cellulose, and have the effect of swelling and deteriorating the wood, but as the wood strands dry, they turn into fatty acids. Since the conversion of wood is suppressed, this kind of deterioration of wood materials can also be reduced.

It is also possible to mix a fatty acid salt as a catalyst into the fatty acid anhydride, but since the fatty acid salt does not dissolve in the fatty acid anhydride, this is not possible in the case of materials with a complex structure such as wood. , it is difficult to expect good catalytic effects from fatty acid salts.

Furthermore, since fatty acid salts are used as catalysts, they do not significantly deteriorate wood materials like general-purpose catalysts such as sulfuric acid or perchloric acid, and excess fatty acid salts can be easily removed by washing the wood materials. can.

In addition, since the fatty acid salt that is the catalyst is impregnated into the wood material in the form of an aqueous solution without using an organic solvent, it is not impregnated into the wood components, especially the crystalline region of cellulose. Since it does not involve a reaction that significantly amorphizes the crystal structure, it is possible to obtain modified wood without deterioration in strength properties.

In addition, in the case where the wooden shrine is made of a thick plate-like material, pillar-like material, etc., the method of the present invention can be applied only to the surface layer thereof.

Next, an example will be described.

In this example, Yonetsuga veneer is used as the wood pseudophase, and
Vinegar-potassium made by heating this rice toga veneer to about 70 degrees Celsius.
The veneer is impregnated with potassium acetate by immersing it in 5% concentration melt.

Next, this veneer is placed in a dryer at 100° C. and dried until the moisture content becomes 5% or less.

Furthermore, the above veneer was immersed in an acetic anhydride solution heated to 110°C to 120°C, reacted for 5 minutes, washed with warm water, and dried with a dryer to increase the weight increase rate (apparent acetyl An acetylated veneer with an acetylation rate of about 25% was obtained.

The acetylated veneer thus obtained was subjected to various tests together with untreated Yoneko veneer, and the following results were obtained.

Firstly, the preservative efficacy of i5A9302 was tested using a mycelium cultured from the decaying fungus Ophthalmia japonica at a temperature of 26°C.
When the weight loss rate was measured after being left under conditions of 70% humidity for 3 months, the weight loss rate was approximately 1% for the acetylated veneer, while it was approximately 15% for the untreated veneer. It was confirmed that the treated veneer had excellent preservative power.

Second (this) Both of the above veneers were buried in a nest of house termites and a 4-month termite test was conducted, and the weight loss rate was measured; the weight loss rate was 0% for the acetylated veneer, whereas it was untreated. The veneer showed a value of about 25%, indicating that the acetylated veneer had excellent termite-proofing performance.

Thirdly, the acetylated veneer was tested for 500 hours using a Sunshine type weather resistance tester, and there was no discoloration or other deterioration, making it clear that it had excellent weather resistance.

Fourth, when we conducted a water absorption measurement test by immersing both veneers in water at 25°C for 24 hours, we found that the acetylated veneer absorbed less than half the amount of water compared to the untreated veneer. It was recognized that it has excellent waterproof performance.

Fifth, 20°C relative to the dimensions in an absolutely dry state.

Dimensional change when equilibrium is reached under 65% humidity conditions (
When the elongation rate) was measured for both of the above veneers, the elongation rate of the acetic and chilled veneer was less than 1/4 of that of the untreated veneer in the radial direction, tangential direction, and fiber direction. It was found to have excellent dimensional stability.

Sixth, in measurements of network strength and bending strength, the strength properties of the acetylated veneer did not deteriorate as compared to the untreated veneer as described above, but rather were slightly improved.

As is clear from the above description, according to the present invention, a wood material is impregnated with an acylation catalyst consisting of an aqueous solution of a fatty acid salt, dried, and then the wood material is treated with a fatty acid anhydride to form hydroxyl groups in the wood components. By modifying the wood material by converting it into Nasil, the wood material has antiseptic properties, anti-termite properties, weather resistance, dimensional stability, etc. without significant deterioration of its strength properties, and its durability is improved. can be improved. At the same time, wood materials, which conventionally could not be chemically modified in industrial production due to their complicated composition and structure, can be modified efficiently and favorably. This has great effects.

In addition, the wood modified by the above method can of course be used as is, but if it is in the form of a veneer, stones may form on the surface of the wood, such as columns or plates, or if it is laminated or can be used by changing it to other shapes.

Therefore, it can be used not only for construction materials, furniture materials, musical instruments, cabinets, etc., but also for a wide range of applications such as plumbing, exterior parts, etc. where the use of wood is limited due to durability. It is possible.

Claims (2)

[Claims] (1) A wood material characterized in that the wood material is impregnated with an acylation catalyst consisting of an aqueous fatty acid salt solution and dried, and then the wood material is treated with a fatty acid anhydride to acylate the hydroxyl groups in the wood components. Modification method. (2) The method for modifying wood materials according to claim 1, wherein the fatty acid salt is an acetate, and is a fatty acid anhydride or a lower fatty acid anhydride such as acetic anhydride.