JPH08207016A - Silica-impregnated wood and manufacture thereof - Google Patents

Abstract

PURPOSE: To obtain building wood, which has high strength and rotproofing-, mothproofing-, ant-proofing-, mildewproofing-properties and flame retardancy. CONSTITUTION: Dried woods 12a,...12d are bound with string 14 under the state being interposed by spacers 13 and put in an impregnating chamber 11 and sealed. By operating cocks 19 and 20, the impregnating chamber 11 is evacuated so as to evacuate the lumina of the wood texture of the wood 12. The wood 12 in the evacuated impregnating chamber 11 is immersed in impregnating solution 16 (or colloidal solution of silica particle blended with boron compound) stored in a container 15. After that, by bringing the pressure in the impregnating chamber 11 to the normal pressure, the impregnating solution is infiltrated in the wood texture. Then the wood 12 is taken out of the chamber and dried at the temperature not more than 60 deg.C. Since the impregnating solution is prepared by mixing boron compound with the colloidal solution of silica particle, the silica particle-impregnated wood consists of the wood 12, non-combustible and high strength silica and rotproofing-, mothproofing-, ant-proofing- and mildewoproofing-boron compound.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to silica-impregnated wood and a method for producing the same. More specifically, the present invention relates to silica-impregnated wood, in which fine particles of silica (silicon dioxide) and a boron compound are adhered and bonded to the interior of the wood to be suitable as a construction material. The present invention relates to wood and a manufacturing method (here, adhesion / bonding means physical adhesion, adsorption, physical containment, chemical bonding, etc.).

[0002]

Wood is a reproducible source of biomaterials,
It has been closely related to human life since ancient times, and has been used for construction, furniture, paper, pulp, fuel, etc., but its consumption tends to increase with the sophistication of life. Wood is an assembly of xylem cells of a plant, and the walls of the xylem cells are reinforced with hemicellulose and lignin with cellulose as the skeleton, so they have the characteristics of being light and strong and easy to work with. Furthermore, wood has heat insulation,
It is particularly indispensable as a building material because it has excellent sound insulation and electrical insulation properties and also has a humidity control function. As wood for general construction, it is particularly necessary to make it easy to work, and coniferous wood that has a column-shaped straight trunk and grows concentrically in large numbers is often used.

[0003]

Wood as a building material has many of the above-mentioned excellent characteristics, but on the other hand,
If the topsoil on the ground surface where the house was built is, for example, one that has been prepared from a high-moisture field or paddy field, or around a water in a kitchen, etc. Will cause decay and mold, or cause damage to the beetle, termites, and other food damage, and reduce the strength of the house.
Furthermore, since it burns easily, it has a problem that it is vulnerable to fire when used in a house.

The present invention has been made in view of the above circumstances, and provides a building material which has high hardness and strength as a building material, has insect repellent, ant-proof, antiseptic and antifungal properties and is hard to burn. It was made for the purpose.

[0005]

In order to solve the above problems, the present invention provides (1) a colloidal solution of a boron compound mixed with a colloidal solution of silicon dioxide fine particles inside a wood under reduced pressure or under pressure. After impregnation, in the composite member obtained by drying the wood, the silicon dioxide fine particles and the boron compound are attached and bonded to the wood constituent components, and further, (2) in the above (1), The average diameter of the silicon dioxide fine particles is 2 to 400 nm, and further,
(3) In the above (1), the boron compound is boric acid and / or sodium borate and / or metallic boron, and (4) In the above (1), the silicon dioxide fine particles are added. That the boron compound is attached / bonded, and (5) in any one of (1) to (4) above, the drying temperature of the wood impregnated with the silicon dioxide fine particles is 60 ° C. or lower. It is a feature.

[0006]

[Function] A colloidal solution of fine particles of silicon dioxide (hereinafter referred to as silica) mixed with a boron compound is impregnated into a microcavity such as a conduit or a temporary conduit that constitutes the xylem of a timber under reduced pressure and pressurization. It is impregnated with impregnating means such as impregnation and then dried to remove the liquid phase in the colloidal solution to form a silica layer containing a boron compound in the wood, making use of the characteristics of noncombustible silica to make a flame-retardant member. And
Increases hardness strength, and further, insect repellent property by boron compound,
Improves anti-termite, antiseptic and antifungal properties.

[0007]

EXAMPLES First, wood, a colloidal silica solution, and a boron compound, which are constituent elements of the silica-impregnated wood of the present invention, will be described. First, wood will be described. Wood is a part of the trunk of a straight columnar tree that is obtained by removing the bark from the trunk, and in the tree, water and nutrients absorbed from the roots are sent to the leaves through the interior of the trunk,
The leaves produce a photosynthetic solution. The produced photosynthetic material passes through the bark and is translocated to each part of the tree to grow the wood. Usually, the stem is columnar and grows concentrically, so the xylem tissue is composed of cells arranged in the stem axis direction.
It is composed of cells arranged radially from the central axis, the marrow. Since coniferous trees such as pine, cedar, and cypress are used as building materials, the cell composition of red pine wood will be described as an example.

FIG. 1 is a schematic view for explaining an example of the cell constitution of Japanese red pine wood, in which X is a transverse cross section, T is a tangential cross section, R is a radial cross section, 1 is a temporary wood temporary pipe, Reference numeral 2 is a temporary material pipe, 3 is an annual ring boundary, 4 is an axial resin path, 5 is an axial parenchyma cell, 6 is an axial plastic path, 7 is a radial parenchyma cell, and 8 is a radial virtual tube.

At the cross section X of the red pine wood shown in FIG.
It has an early wood part consisting of an early wood temporary pipe 1 and an late wood part consisting of a late wood temporary pipe 2, and an annual ring boundary 3 which is a boundary between the early wood part and the late wood part is seen, and an inner diameter 40 The cross sections of the temporary material temporary pipe 1 having a diameter of -60 μm and the temporary material temporary pipe 2 having an inner diameter of 8 to 25 μm are lined up in order, and a large-diameter axial resin path 4 is arranged in this. Further, the radial cross section R and the tangential cross section T have an inner diameter of 30 to 55 μm.
The radial soft cells 7 of m and the temporary radiation tube 8 are arranged side by side.

As described above, the red pine wood has the characteristics that it is lightweight and has high compressive strength because the hollow conduit formed by the cell wall is formed on the surface of the cross section X, the tangential cross section T, and the radial cross section R that intersect at right angles. Such a wood structure configuration is substantially the same in other coniferous trees used for building materials.

Next, the silica fine particles will be described. The colloidal silica solution is a colloidal solution in which fine spherical silica is dispersed in water, and OH groups are present on the surface of silica particles.
It is negatively charged by the OH group. The colloidal liquid has low viscosity and Newtonian viscosity, and the specific gravity increases as the amount of silica fine particles increases and the concentration increases. For example, the specific gravity of silica fine particles at a weight percentage of 30% is about 1.2. Then, the viscosity at this time is 3 cp (at 25
℃) or less. Further, when dried and heated, the water adsorbed on the silica fine particles is removed, and when the heating is further continued, the silica is firmly fixed to the surface of the colloidal solution. Silica is a stable, hard inorganic compound that exists in large amounts on the ground, is nonflammable, and increases in hardness due to the adhesion of silica fine particles.

Next, the boron compound will be described. The boron compound is, for example, boric acid (boric acid), and the boric acid is an oxygen acid (oxy acid) generated by hydration of diboron trioxide (B ₂ O ₃ ), orthoboric acid (H ₃ BO ₃ ), Metaboric acid (HBO ₃ ), tetraboric acid (H ₂ B ₄ O ₇ ) and the like are included, and orthoboric acid (H ₃ BO ₃ ) is simply called boric acid. These boric acids are used for the insect repellent, ant repellent and antiseptic properties of wood.
It has properties such as mold resistance. Next, specific examples of these characteristics will be described in Tables 1 to 4 below.

[0013]

[Table 1]

Table 1 is for explaining an example of the insect repellent test results of wood using a boron compound, in which the boron compound is a boric acid compound, and the insect pest used is a flat beetle, the insect repellent effect. The test is based on the insect repellent efficacy test of wood (Japanese Wood Preservation Association Standard No. 8, 1979.), and the flat beetle, No. 9, 1979. Were artificially reared, and boric acid having different concentrations per unit area was applied to test the larvae for food perforation, emergence and emergence. According to the results in Table 1, the concentration of boric acid equivalent to the untreated one was about 7% or more, and the number of larvae for food perforation, emergence and emergence, and the number of adults were drastically reduced. (2) Satisfies the adult test.

[0015]

[Table 2]

Table 2 is for explaining an example of the test result of the termite-proof property of the wood by the boron compound. The boron compound is a boric acid compound, the termites used are the termites, and the boric acid compound is the orthoboric acid. (H ₃ BO ₃ ) is one of the tests tested in three types of treated soils in which the boric acid equivalent concentrations of 7%, 10%, and 20% were treated in the soil. Although it penetrated, it was confirmed that the movement after the penetration became slow, the feeding ability was lost, and death gradually occurred.

[0017]

[Table 3]

Table 3 is for explaining one example of the results of the wood antiseptic test using a boron compound. The boron compound is orthoboric acid H ₃ BO ₃ (simply referred to as boric acid).
It was performed according to JAS-A9302 [Test method of preservative efficacy of wood preservatives], and the weight reduction rate is (1/4) even when the concentration of boric acid is 1% compared to the case of no treatment. It was confirmed below that the wood preservative effect could be obtained.

[0019]

[Table 4]

Table 4 is for explaining an example of the soil bactericidal test results by the boron compound, the boron compound is boric acid, and the bacterial species used is Namitake FFPR10.
As a result of adding boric acid to 100 g of a mixture of Kanuma soil, spruce pine wood flour, and city water at a predetermined ratio, and culturing for 2 months, on the bacterial culture soil in which each of the Namidatake HFP7802 was cultivated with 703 and Namidatake HFP7802. Thus, it was confirmed that boric acid concentration of 1% completely suppressed the growth of Namitake mushrooms as compared with the case of no treatment.

[0021]

[Table 5]

Table 5 is a diagram for explaining an example of the fungicide-proof test with a boron compound, and the boron compound is orthoboric acid H ₃ BO ₃ (B (OH) ₃ : simply referred to as boric acid).
The boric acid content is expressed as a weight percentage with respect to the sample weight, and the test bacteria are expressed as the number of test bacteria in the culture solution (ml (milliliter)). Table 5
According to the result of the fungicidal test according to No. 3, the fungus was enhanced when boric acid was not added, but it was killed when the boric acid content was about 10%.

By fixing the above-mentioned non-combustible silica fine particles and the boron compound having insect, ant, antiseptic and antifungal properties in a large number of conduits, temporary conduits and the like in the wood tissue, a building material is obtained. It is possible to solve the problem that untreated wood is inferior in insect control, ant control, antiseptic and antifungal properties and is easily burned. In the present invention, silica fine particles are used as a colloidal solution to generate a repulsive force between the fine particles to prevent the particles from binding to each other and impregnate the particles.

The colloidal solution of silica fine particles is further mixed with a boron compound to obtain a colloidal solution containing silica fine particles and a boron compound. The above-mentioned colloidal solution is impregnated into the wood tissue in a reduced pressure air or a pressurized air (in this specification, an example of impregnation by a reduced pressure is shown, but it can be easily understood that it may be impregnated by a pressure). ), By drying the impregnated wood, silica and boron compounds are chemically bound or physically adsorbed to the wood constituents, and further, silica fine particles are bound to each other to form a gel. A silica-impregnated wood in which a boron compound is physically contained is obtained (corresponding to claim 1).

Since the silica-impregnated wood thus obtained contains the boron compound and silica in the wood structure stably, it retains the features of conventional wood and is repellant-proof.
It has anti-termite, antiseptic and antifungal properties, is flame-retardant, and can be made into high-hardness construction wood. In particular, excellent properties can be obtained as a wood for the base or around water.

FIG. 2 is a view for explaining an example of an apparatus for producing silica-impregnated wood according to the present invention, in which 1
0 is an impregnation device, 11 is an impregnation chamber, 12 is wood, 13 is an intermediate, 14 is a string, 15 is a container, 16 is an impregnation solution (a colloidal solution of a silica fine particle mixed with a boron compound), and 17 is a liquid. A tube, 18 is a trachea, and 19 and 20 are cocks.

The impregnation apparatus 10 includes a decompression means which communicates with the impregnation chamber 11 closed by a door 11a to decompress the inside of the impregnation chamber 11, and an impregnation chamber 11 in which the impregnation solution 16 pressurized by atmospheric pressure is decompressed. It is composed of a liquid pipe 17 leading into the interior and an infusion means composed of a container 15. A two-way switching cock 19 is attached to the liquid pipe 17, and the impregnation solution 16 is introduced into the impregnation chamber 11 by opening the cock 19. Also, the liquid pipe 1
A cock 20 for three-way switching is attached to 7, a trachea 18 for depressurizing the inside of the impregnation chamber 11 is connected to the cock 20, and a trachea 18 and a vacuum pump (not shown) are further connected to the cock 20. By changing the cock 20, the inside of the impregnation chamber 11 can be evacuated or the impregnation solution 16 can be injected into the impregnation chamber 11.

At this time, the average particle diameter of the silica fine particles of the impregnation solution 16 is such that a colloidal solution can be formed and the silica fine particles have an inner diameter of 8 to 6 such as a conduit of a wood tissue of the wood 12 or a temporary conduit.
The average diameter of the silica fine particles is 2 to 40, which is sufficiently smaller than the inner diameter, because the size of the silica fine particles is required to be within the cavity of 0 μm.
It must be 0 nm (nanometer) (corresponding to claim 2).

Further, the boron compound is mixed in a colloidal solution of silica fine particles trioxide bimodal element (B ₂ O _3: simply referred to as boron oxide) is produced by hydration orthoboric acid (H
_{3 BO 3: B (OH)} 3), in addition to, sodium borate, such as borate (Na ₂ B ₄ O ₇₎ of metaboric acid (HBO _2), tetraborate _{(H 2 B 4 O 7)} , Alternatively, even if metal boron (for example, zinc borate, copper borate, manganese (II) borate, etc.) (corresponding to claim 3) is used, it has antiseptic, insecticidal, ant, and antifungal effects as a boron compound. .

Further, when the wood is impregnated with a colloidal solution in which a boron compound is mixed with a colloidal solution of silica fine particles and dried to remove water in the colloidal solution,
The silica fine particles and the boron compound are attached and bonded (corresponding to claim 4).

The above-mentioned boric acid is orthoboric acid (H
₃ BO ₃ ), but as the boron compound, boron oxide (B ₂ O ₃ ) or sodium borate (Na ₂ B
₄ O ₇ ), metaboric acid (H
The same effect can be obtained by using either BO ₂ ) or tetraboric acid (H ₂ B ₄ O ₇ ), or a combination of two or more of the above boron compounds (corresponding to claim 5).

In FIG. 2, the order of impregnating the wood 12 with the impregnation solution 16 made of the above substances is as follows: (1) For example, the wood 12a, which is a square pillar-shaped wood 12 having a length of 4 to 5 m, , 12d are separated by an interposer 13 so as not to be surface-bonded to each other, and are bundled by a string 14 and inserted into the impregnation chamber 11. After the insertion, the door 11a is closed. (2) The cock 19 is closed so that the liquid pipe 17 does not communicate with the container 15 side, and then the cock 20 (three-way switching cock) is operated to join the trachea 18 with a vacuum pump (not shown).
And the impregnation chamber 11 are communicated with each other. (3) The gas in the impregnation chamber 11 is evacuated, and the inside pressure is sufficiently reduced. (4) Operate the cock 20 to close the trachea 18 side, then
The cock 19 is opened, the impregnation solution 16 is introduced from the liquid pipe 17 into the pressure-reduced impregnation chamber 11, and the wood 12 is left immersed in the impregnation solution 16 for one night or longer, so that the impregnation solution 16 is sufficiently contained in the wood 12 tissue. Infiltrate. (5) The wood 12 is taken out from the impregnation chamber 11 and dried at a temperature of 60 ° C. or lower (corresponding to claim 6). At a temperature of 60 ° C. or lower, the wood 12 impregnated with silica fine particles can be dried without being deformed.

Concrete Example 1. Material and manufacturing method (1) Wood: Japanese cypress, Japanese cedar, pine (10 mm long x 8 horizontal)
(0 mm x thickness 5 mm) (2) Colloidal silica solution: Cataloid SI-30 (manufactured by Catalysts & Chemicals Industry Co., Ltd .: (SiO ₂ Wt%: 30%, particle size: 1
1-12 nm: viscosity 3 cp, specific gravity: 1.2) (3) Boron compound: boric acid, metallic boron (zinc borate, copper borate, manganese borate (II), etc.) 1. Manufacturing method (1) A cypress (cedar, pine) material is dried under a reduced pressure of about 12 mmHg for about 30 minutes. (2) Ratio of 1 ml of boric acid aqueous solution (milliliter) to 40 ml of colloidal solution of Cataloid SI-30 (4
Prepare 20 ml of the colloidal solution mixed with 0: 1), and quickly drop 150 ml of it into the cypress (Japanese cedar, pine) material under reduced pressure so that the entire surface of the cypress (Japanese cedar, pine) material may come into contact with the solution and get wet. Shake well and let stand for 10 to 15 minutes. (3) After 15 minutes have passed, the remaining 50 ml is dripped all at once to return the cypress (cedar, pine) material to the normal pressure state. (4) Leave the wood soaked in the solution for 12 hours or more. (5) The wood is taken out of the solution and dried at a temperature of 60 ° C. for 48 hours.

[Impregnated amount of silica and boron compound in silica-impregnated wood] Table 6 shows the impregnated amount of silica and boron compound impregnated in cypress (cedar, pine) by the above-mentioned production method 2. The ratio of the boron compound to the silica is approximately constant and is about 20: 1, though it changes depending on the wood structure and becomes smaller in the order of cedar, cypress, and pine.

[0035]

[Table 6]

[Test Results of Silica Impregnated Wood] 1. Surface hardness test (1) Testing machine: Rockwell hardness tester (steel ball diameter = 6.3)
50mm, scale L) (2) Test method: Basic load 10kgf → Test load 60kgf →
Basic load 10kgf (3) Hardness test result: As shown in Fig. 3, the surface hardness of the hinoki material not impregnated with the solution is 2.3 (Rockwell tester, L
The hardness of the scale is HRL), whereas the surface hardness of the silica-impregnated wood is 44.3 (HRL) on average, which is about 20 times the hardness. The hardness of cedar wood and pine wood is HRL: 56 and 40, respectively, and the hardness is 20 times that of the untreated case. 2. Flame-retardant test (1) Heater: Gas burner (2) Heating method: Adjust the gas burner so that it has a constant and relatively weak flame, and in this flame, the corners of the test material (cedar, pine timber) For 10 seconds. After 10 seconds, the test material is removed from the flame, allowed to stand in the air, and the time until the flame disappears is measured with a stopwatch. (3) Results of flame retardancy test: Table 7 shows the results of flame retardancy evaluation test. Untreated wood had a large flame, untreated cedar wood extinguished in 15 seconds, but untreated pine wood. Keeps the flame going on. In contrast, the silica-impregnated material had a rounder and smaller flame than the untreated material, the cedar wood immediately extinguished, and the pine wood extinguished in 3 seconds. The color of the flame was a brighter orange color than the untreated material, and the untreated wood in the burnt part peeled off in a mica-like shape parallel to the surface so that the bark of the tree could be peeled, but the silica-impregnated wood was a smooth powder. I was in a state of distress.

[0037]

[Table 7]

3. Change test of residual silica rate (1) Silica-impregnated wood: The method for producing silica-impregnated wood is based on the above-mentioned reduced pressure impregnation method, but the silica content relative to the boron compound is (1:40), (1:60), ( 1: 8
The wood impregnated into three types (0) is dried (air dried) at room temperature for 20 days. For example, the silica content ratio (1:40) is 40% boric acid aqueous solution (B (OH) ₃ ) based on 40 ml of the stock solution of the colloidal solution of Cataloid SI-30.
This is a colloidal solution mixed at a ratio of 1 ml. (2) Test method Weather-resistant operation of submerging the air-dried silica-impregnated wood in 4 l (liter) of ion-exchanged water and stirring for 8 hours, and heating-drying of drying the silica-impregnated wood after weathering operation at 60 ° C. for 16 hours. The test results were obtained by repeating the weathering operation and heating and drying 10 times, with 1 and 1 as the leaching cycle. (3) Test Result FIG. 4 is a diagram showing an example of a change test result of the residual silica rate in wood, wherein the horizontal axis shows the number of times of leaching (times) and the vertical axis shows the residual silica rate (%). The silica content with respect to is used as a parameter. According to FIG. 4, silica content
(40: 1), (60: 1), (80: 1) silica-impregnated wood in the ion-exchanged water, compared to 10 times leaching times, even if the leaching number increases, silica fine particles in the wood Is
It was shown that almost no leaching occurred from the wood, and it was proved that the silica fine particles were stably fixed to the wood structure.

[0039]

As is apparent from the above description, the present invention has the following effects. (1) Effect corresponding to claim 1: In a cavity of a depressurized wood structure where wood is placed in a depressurized atmosphere, fine particles of non-combustible silica, which is an inorganic material, and a boron compound having antiseptic, insect, ant, and fungicidal properties are used. As they are mixed and chemically bonded, physically adsorbed or physically encapsulated and fixed, each has stable chemical properties and strength, is free of organic compounds and is safe, antiseptic, insect repellent, termite repellent, It has an excellent effect as a mold base material and a water supply material. (2) Effect corresponding to claim 2: Since the average diameter of the silica fine particles is set to 2 to 400 nm, the average inner diameter is 8 to 60 μm.
The silica fine particles are sufficiently smaller than the wood structure cavities of (1) and are uniformly and stably fixed in the cavities, and strength and noncombustibility can be maintained. (3) Effect corresponding to claim 3: Since the boron compound is boric acid, sodium borate, or metallic boron, insect repellent,
A silica-impregnated wood which is antiseptic, ant-proof and mildew-proof is obtained. (4) Effect corresponding to claim 4: The same effect as claim 1 can be obtained. (5) Effect corresponding to claim 5: The range of the boron compound having the effect of claim 3 can be broadened. (6) Effect corresponding to claim 6: Stable fixation of silica fine particles and a boron compound in a wood tissue without thermally deforming wood impregnated with a colloidal solution of a silica fine particle mixed with a boron compound. You can

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining an example of cell constitution of Japanese red pine wood.

FIG. 2 is a view for explaining an example of an apparatus for producing silica-impregnated wood according to the present invention.

FIG. 3 is a L-scale hardness comparison diagram of a Rockwell hardness meter for silica-impregnated wood and untreated wood according to the present invention.

FIG. 4 is a diagram for explaining the residual silica change rate of silica-impregnated wood according to the present invention.

[Explanation of symbols]

X ... transverse section, T ... tangential section, R ... radial section, 1 ... early material temporary tube, 2 ... late material temporary tube, 3 ... annual ring boundary, 4 ... axial resin, 5 ... axial soft cell, 6 ... Axial resin construction, 7 ... Radial flexible cell, 8 ... Radiation temporary tube, 10 ... Impregnation device, 11 ... Impregnation chamber, 12 ... Wood, 13 ... Inclusion, 14 ... String, 15 ... Container, 16 ... Impregnation Solution (colloidal solution of boron compound mixed with colloidal solution of silica fine particles), 17 ... Liquid tube, 1
8 ... trachea, 19,20 ... cock.

Claims (5)

[Claims] 1. A composite member obtained by impregnating the interior of wood with a colloidal solution of a boron compound mixed with a colloidal solution of fine particles of silicon dioxide in reduced pressure or pressurized air, and drying the wood. In addition, silica-impregnated wood, characterized in that fine particles of silicon dioxide and a boron compound are attached and bonded. 2. The average diameter of the silicon dioxide fine particles is 2 to
The silica-impregnated wood according to claim 1, which is 400 nm. 3. Silica-impregnated wood according to claim 1, characterized in that the boron compound is boric acid and / or sodium borate and / or metallic boron. 4. The silica-impregnated wood according to claim 1, wherein a boron compound is attached and bonded to the silicon dioxide fine particles. 5. The method for producing silica-impregnated wood according to claim 1, wherein the wood impregnated with the silicon dioxide fine particles has a drying temperature of 60 ° C. or lower.