JPH01200903A - Method for modifying wood - Google Patents

Abstract

PURPOSE:To improve the swelling/contraction quantity of wood after modification to a large extent, by allowing a substance, whose swelling coefficient to the wood is larger than that of water, to coexist at the time of the etherification of the wood. CONSTITUTION:A block material subjected to solvent extraction and hot water extraction is immersed in a solvent mixture consisting of an epoxy compound and pyperidine and the impregnated one is heat-treated at about 120 deg.C for 1hr under pressure. As the epoxy compound being an etherifying agent, concretely, ethylene oxide, propylene oxide or epichlorohydrin can be employed. Other than pyperidine, amine or amine type compound whose swelling coefficient to wood is larger than that of water can also sufficiently reduce swelling/ contraction quantity without bringing about the deterioration of wood quality.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for modifying wood, and more particularly to a method for modifying wood by etherifying hydroxyl groups in wood using an etherifying agent.

(Prior art) Wood has a high specific strength compared to other materials, is highly elastic, has good adhesive properties, and is easy to process, so it is used in a wide range of applications such as various construction materials and furniture materials. On the other hand, it has the fatal disadvantage of being non-uniform, rotting, hygroscopic, etc., and the accompanying deformation cannot be avoided. Various methods for improving the quality of wood have been investigated in order to improve the inherent disadvantages of wood, but among them, the method of treating wood with various alkaline compounds and then etherifying it is a method that improves the quality of wood. It is attracting attention as a method for improving the quality of wood because it has the advantages of reducing deformation due to hygroscopicity and at the same time contributing to improving decay resistance.

This method focuses on the fact that moisture absorption in wood is caused by the bond between hydrophilic groups, especially hydroxyl groups, and water molecules present in the wood's constituent substances, and by etherifying the hydroxyl groups in wood, the wood has a tube effect. This method imparts a bulking effect (bulking effect) and swells the wood in advance, thereby reducing deformation due to moisture absorption and desorption of the wood, thereby imparting dimensional stability. In particular, in order to reduce the hygroscopicity of wood and increase its dimensional stability, it is necessary to replace the OH groups in the wood with epoxy groups and to fix the wood in the maximum swelling state. It is necessary to prevent further swelling even in wood swelling atmospheres such as wood swelling atmospheres.

In this material improvement method by etherification of wood, it is necessary to use various alkaline compounds as catalysts, and conventionally triethylamine, sodium hydroxide, etc. have been used as such catalysts, but these alkaline catalysts In addition to being accompanied by material deterioration, it also had the disadvantage that the amount of swelling and shrinkage of the wood after modification was insufficiently reduced.

The inventors of the present invention have made intensive studies to solve the drawbacks of the conventional methods, and have found that, when etherifying wood, by coexisting a substance that does not inhibit the etherification reaction and has a larger swelling coefficient for wood than water, The present invention was achieved by discovering that the amount of swelling and shrinkage of wood after modification can be greatly improved.

(Problems to be Solved by the Invention) Therefore, a first object of the present invention is to provide a method for modifying wood that does not involve deterioration of the quality of the wood.

A second object of the present invention is to provide a method for modifying wood that can sufficiently reduce the amount of swelling and shrinkage.

The above-mentioned aspects of the present invention are characterized in that in an etherification method in which wood is reacted with an epoxy-based etherification agent, an amine-based or This was achieved by a wood modification method characterized by using at least one compound selected from the group consisting of amide compounds.

The wood used in the present invention is not particularly limited, and the method of the present invention can be applied to all types of wood.

In the present invention, the etherifying agent for etherifying wood can be appropriately selected from known compounds that normally react with hydroxyl groups to etherify.
In particular, it is preferable to use an epoxy compound from the viewpoint of the quality of the material after modification.

Examples of such epoxy compounds include ethylene oxide, propylene oxide, butylene oxide, and epichlorohydrin.

When etherifying the above-mentioned compounds, a basic substance is usually used as a catalyst.

In the present invention, at least one compound (hereinafter referred to as amine, etc.) selected from the group of amine-based or amide-based compounds whose swelling coefficient for wood is larger than that of water is used during etherification, but these compounds Since it is basic, it not only functions as a swelling agent for wood but also as a catalyst for the etherification reaction between the hydroxyl groups of wood and the epoxy compound, so there is no need to use any other catalyst.

However, it goes without saying that other catalysts may be used in combination as necessary, and the above amine compounds and amide compounds may also be used in combination.

Examples of amines or amides that can be used in the present invention include n-butylamine, piperidine, pyridine, dimethylformamide, and the like.

(Function) As mentioned above, the amines used in the present invention have a larger swelling coefficient for wood than water, so the etherification reaction of wood is carried out in a state where the wood is more swollen than the state where the wood absorbs water and swells. can be set.

Furthermore, since the amine used also functions as a catalyst for the etherification reaction, there is no need to use conventional catalysts that cause material deterioration of wood.

The amount of amine etc. to be used is such that it can exhibit its swelling function. Therefore, it is usually preferable to use at least 5% by weight of the etherifying agent. Amines and the like are expensive, and the initial objective of the present invention can be achieved if the wood after modification hardly swells even when it absorbs water, so it is necessary to use an amount that causes the wood to swell to the same extent as when it absorbs water. It is sufficient to use amines, etc.

The etherification reaction in the present invention can be suitably carried out under known conditions and using known equipment.

In general, amines are often harmful to living organisms (and are also expensive), so in the present invention, it is preferable to thoroughly wash with water after the etherification reaction is completed, and extract the amines into water for recovery. Even if the amine is recovered, the wood will not shrink because it has already been modified by etherification, nor will it absorb water and swell.

(Effects of the Invention) According to the present invention, since the wood is etherified in a swollen state, the amount of swelling and shrinkage after modification is significantly improved compared to the conventional modification by etherification.

Furthermore, since there is no need to use an alkaline catalyst that causes material deterioration of the wood during etherification, the quality of the wood after modification is extremely good.

(Example) Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto.

Example 1 Agatis square supplement block material (5 x 35 x 35 mm) subjected to acetone extraction (80°C 8 hours, x 2 times) and hot water extraction (80°C 8 hours) (rs, x 2 times) was extracted from 80 parts of propylene oxide and 20 parts of piperidine. The etherification reaction was carried out at 120° C. and 9.5 kg/cm 2 for 60 minutes. After the pressure was released, the remaining liquid was collected, the test piece was taken out, and it was completely dried in a blow dryer to obtain an etherified block material with a volume increase rate of 6.5% and a weight increase rate of 28%. The anti-swelling ability (
ASE) was 83% in the T direction and 88% in the R direction, which was extremely good.

Example 2 The same procedure as in Example 1 was carried out except that a mixed solution of 80 parts of propylene oxide and 20 parts of dimethylformamide was used instead of the mixed solution of 80 parts of propylene oxide and 20 parts of piperidine, and the volume increase rate was 5. An etherified block material with a weight increase rate of 8% and a weight increase rate of 27% was obtained.

When this was left in a constant temperature and humidity atmosphere of 20°C and 93% RH and the dimensional change rate was measured, the anti-swelling ability (ASE) was as follows.
It was 78% in the T direction and 83% in the R direction.

Example 3 The mixing ratio of the propylene oxide and piperidine mixed solution used in Example 1 was 97/3.9515.90/10
Anti-swelling ability (
ASE) was measured, and the results shown in the following table were obtained.

Comparative Example 1 In Example 1, triethanolamine was used instead of piperidine, and the volume increase rate was 4.8% and the weight increase rate was 28%.
A 5% block material was obtained. When this was left in a constant temperature and humidity atmosphere and the dimensional change rate was measured, the anti-swelling ability (ASE) was 58% in the T direction and 62% in the R direction, which was a large dimensional change.

The results of the above Examples and Comparative Examples demonstrate the effectiveness of the present invention in which etherification is carried out in the presence of an amine or the like having a larger swelling coefficient than water.

Claims (1)

[Scope of Claims] 1) In an etherification method in which wood is reacted with an epoxy-based etherification agent, a compound selected from among the group consisting of an amine-based or amide-based compound having a larger swelling coefficient for wood than water, together with the etherification agent. at least one selected from
A method for modifying wood characterized by using a seed compound. 2) The method for modifying wood according to claim 1, wherein the amount of the amine or amide compound added is at least 5% by weight based on the etherifying agent.