JPH0431004A - Manufacture of modified wood - Google Patents

Abstract

PURPOSE:To obtain a modified wood being dimensionally stabilized to the inside of wood, having water resistance, weatherability and a little remaining odor of unreacted chemicals by impregnating a raw material wood with an aq. solution contg. an ingredient forming an insoluble polymer compd. by irradiating radiation beam and irradiating the radiation beam. CONSTITUTION:As an impregnating ingredient, such an ingredient that is easily infiltrated in wood tissues under a dissolved condition in water and forms a water-insoluble polymercompd. by crosslinking polymn. by irradiating a radiation beam, for example, acrylamide, etc., can be cited. As the radiation beam, with which the wood is irradiated, electron beam, X-rays, gamma-rays, etc., can be cited. When a wood contg. an impregnated ingredient inside is irradiated with the radiation beam, not only the impregnated ingredient existing on the surface of the wood but the impregnated ingredient existing in the cells or voids in the inner cavities of the cells of the wood are crosslinking-polymerized to form and fix a large amt. of an insoluble polymer compd. with a high reaction ratio.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing modified wood used as building materials and the like.

[Prior Art] Conventionally, as a method for stabilizing the dimensions of wood, there are, for example, the following methods (1) to (2).

■ A method of impregnating raw material wood with polyethylene glycol.

■ A method of thermosetting resin that is impregnated into raw wood under reduced pressure.

■ A method of making open groups hydrophobic by acetylating the hydrophilic OH groups of cellulose components in wood.

[Problem to be solved by the invention]

However, each of the methods ① to ① described below (al
~ fc).

(al) Polyethylene glycol is water-soluble and easily penetrates into the wood, but it is difficult to make it water-insoluble and fix it inside the wood, so polyethylene glycol leaks out of the wood due to water or moisture, reducing performance. In other words, it has poor water resistance and weather resistance.

Since it is difficult for resin to penetrate into the interior of the wood, in practice the treatment is limited to a thickness of less than 1 Tsuru (often about 0.31111 mm) from the surface of the wood.

In other words, the interior of the wood is not dimensionally stabilized.

(C) It is difficult to completely acetylate the cellulose inside the wood, so it may not be possible to stabilize the dimensions of the wood or achieve a sufficient acetylation rate, leaving behind the odor of unreacted acetic acid. or

In view of these circumstances, the present invention provides a method for efficiently obtaining modified wood that is dimensionally stable to the inside of the wood, has water resistance, weather resistance, etc., and has little residual odor from unreacted chemicals. The challenge is to provide the following.

[Means to solve the problem]

In order to solve the above problems, the method for producing modified wood according to the present invention involves impregnating raw wood with an aqueous solution containing a component (hereinafter simply referred to as "impregnating component") that produces an insoluble polymer compound by radiation irradiation. After this, the wood is irradiated with radiation to generate and fix the insoluble polymer compound within the wood structure.

The raw material wood to be modified in the present invention is not particularly limited, and examples thereof include raw wood logs, sawn timber products, sliced veneers, plywood, and the like. There are no limitations on the tree species, etc. They may also be untreated wood,
It may be wood that contains an insoluble, nonflammable inorganic substance inside.

The impregnating component used in this invention is one that can be easily impregnated (penetrated) into the wood tissue in a state dissolved in water, and that can be cross-linked and polymerized by radiation irradiation to produce a water-insoluble polymer compound. There is no particular limitation as long as it is. For example, even if the molecular weight is somewhat high, it has a nearly linear structure such as a chain structure and can penetrate relatively deep into wood cells, or it may not be able to penetrate into wood cells. It may be something that can exist in a state dissolved in water in the cavity of the cell lumen. Specific examples include acrylamide, but are not limited thereto.

The method of impregnating the raw material wood with the aqueous solution containing the impregnating component is not particularly limited, and includes, for example, a pressure impregnation method, a reduced pressure impregnation method, a diffusion impregnation method by immersing saturated wood in an impregnating liquid, etc. I can do it. The concentration of the impregnating liquid, the impregnating temperature, the impregnating time, etc. are not particularly limited.

The radiation irradiated to the wood after the impregnation treatment is not particularly limited as long as it cross-links and polymerizes the impregnating component to produce a water-insoluble polymer compound, for example, Examples include electron beams, X-rays, and T-rays. Only one type of these radiations may be irradiated, or multiple types of radiation may be irradiated if necessary. There are no particular limitations on the irradiation time, etc.

Although not particularly limited, before irradiating the impregnated wood with these radiations, it is preferable to pre-dry the wood to remove excess moisture.

[For production]

When impregnated with an aqueous solution containing a component (impregnation component) that generates an insoluble polymer compound by radiation irradiation,
Since the impregnating component is water-soluble and has excellent permeability into the interior of the raw material wood, it is impregnated into the interior of the cells of the same wood or into the voids of the intracellular cavities. However, in this state, even if excess moisture is removed from the wood, the impregnating component is hydrophilic, so it is impossible to suppress dimensional changes when the wood swells with water. Furthermore, since the impregnating component is water-soluble, it is known that it flows out of the wood when the wood gets wet with water or is placed under high humidity.

When wood containing this impregnated component is irradiated with radiation, the radiation can pass through the wood, which will not only affect the impregnated component present on the surface of the wood, but also the interior of the cells of the wood or the intracellular cavities. Even the impregnating components present in the voids of the wood undergo cross-linking polymerization, and a large amount of insoluble polymer compounds are efficiently generated and fixed within the wood structure at a high reaction rate. As a result, the residual odor of the unreacted impregnating components is reduced.

The insoluble polymer compound immobilizes the cellulose inside the wood cells in a swollen state, so that the wood remains in an elongated state and further swelling by water is suppressed. In other words, the wood has been dimensionally stabilized to the inside. On the other hand, insoluble polymer compounds generated and fixed in the cavities of wood cell lumens protect the wood cell walls from water and prevent the cells from swelling with water, thereby stabilizing the dimensions of the wood to the inside. . Usually, these two dimensional stabilizing effects occur simultaneously and are synergistic.

In addition, the insoluble polymer compound is insoluble in water and fixed inside the wood, and there is little risk of it flowing out of the wood due to water or moisture, causing a decrease in performance. It also has excellent water resistance and weather resistance.

〔Example〕

Specific examples of the present invention are shown below, but the invention is not limited to the following examples.

Example 1 Agatis veneer (50x50x0.3I [1) was immersed in 80°C water for 24 hours to saturate it with water.

This water-saturated veneer was immersed in a 30% acrylamide aqueous solution for about 8 hours, air-dried for 24 hours, and further heat-dried at 100° C. for 20 minutes.

This dried veneer was placed in a vacuum chamber and irradiated with electron beams to produce modified wood.

The obtained modified wood was immersed in water at 80°C for 1 hour to examine whether soluble components were eluted, but there was no change in weight, and most of the acrylamide reacted with the water. It was observed that the particles were insolubilized.

In addition, for the obtained modified wood, the dimensional change rate expressed by the following formula % formula % () (in the formula, each dimension is measured in the direction perpendicular to the wood fibers) was determined. As a result, the average value was 82%, indicating that the insoluble polymer compound was immobilized in a swollen state of about 80% when saturated with water. Therefore, even if the obtained modified wood swells with water, it will swell by at most 2
It is thought that there is only a small dimensional change.

Example 2 Agatis veneer (50 x 50 x 10 m) was saturated with water under reduced pressure, and then immersed in 80°C water at normal pressure for 24 hours to saturation.

This saturated veneer was immersed in a 30% acrylamide aqueous solution for 24 hours, air-dried for 3 days, and further heated to 100°C for 1 hour.
It was dried by heating for a period of time.

This dried veneer was irradiated with T-rays in the air to produce modified wood.

The obtained modified wood was immersed in water at 80°C for 1 hour to examine whether the soluble components melted, but there was no change in weight, indicating that most of the acrylamide had reacted. It was observed that it was insoluble in water.

Regarding the obtained modified wood, the dimensional change rate was determined in the same manner as in Example 1 and was found to be 75%.

Example 3 In Example 2, 50×50×1ON was used as raw material wood.
Modified wood was produced in the same manner as in Example 2, except that a 50x50x3mM agathis veneer was used instead of the agathis veneer, and X-rays were irradiated instead of T-rays as the radiation.

The obtained modified wood was immersed in water at 80°C for 1 hour to examine whether the soluble components melted, but there was no change in weight, indicating that most of the acrylamide had reacted. It was observed that the substance was insoluble in water.

Regarding the obtained modified wood, the dimensional change rate was determined in the same manner as in Example 1 and was found to be 72%.

Example 4 In the same manner as in Example 3, except that an agathis veneer containing an insoluble incombustible inorganic substance inside was used instead of an untreated agathis veneer as the raw material wood,
Modified wood was produced.

The obtained modified wood was immersed in water at 80°C for 1 hour to examine whether soluble components were eluted, but there was no change in weight, indicating that most of the acrylamide had reacted. It was observed that it was insoluble in water.

Regarding the obtained modified wood, the dimensional change rate was determined in the same manner as in Example 1, and it was found to have improved to 85%.

〔Effect of the invention〕

According to the method for producing modified wood according to the present invention, it is possible to efficiently obtain modified wood that is dimensionally stabilized to the inside of the wood, has water resistance, weather resistance, etc., and has little residual odor from unreacted chemicals. can.

Agent: Patent Attorney Takehiko Matsumoto Procedural amendment (view) Heisei 3 years February 20th Patent Application No. 139374 Hei 2-139374 3゜ person who makes corrections 1. Four genetic lines with timber cattle

Claims (1)

[Claims] 1. After impregnating raw material wood with an aqueous solution containing a component that generates an insoluble polymer compound when irradiated with radiation, the wood is irradiated with radiation so that the insoluble polymer compound is generated and fixed within the structure of the wood. A method for producing modified wood.