JPH11277506A - Inorganic composite method for porous material - Google Patents

Abstract

(57) [Problem] To provide an inorganic composite method with increased decay, flammability, and dimensional stability by precipitating an inorganic substance on a porous body to form a composite. SOLUTION: A porous body is put into a pressure vessel, a single solution of which pH and concentration are adjusted is injected and impregnated, and then a gas is injected to perform a deposition reaction of an inorganic substance by operating pressure and temperature. The inorganic composite method is used as a basic means. Specifically, the solution is injected from the valve of the pressure vessel to impregnate the wood, the pressure inside the pressure vessel is raised to atmospheric pressure, then carbon dioxide gas is injected from the valve, and the pressure is maintained for a predetermined time. The temperature of the inside of the pressure vessel is increased by external heating to cause a precipitation reaction of the inorganic material inside the porous body. An aqueous solution in which alkanolamine and calcium nitrate are mixed at a molar ratio of 2: 1 is used as a solution for impregnating the inside of the porous body, and an alkaline earth metal carbonate is used as an inorganic material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inorganic compounding method for a porous material, and more particularly to a method for depositing an inorganic substance on wood to form a composite, thereby improving decay, flammability and dimensional stability. It is about.

[0002]

2. Description of the Related Art Taking wood as an example of a porous body, wood generally has the disadvantages of being decayable and flammable, has poor dimensional stability, and is easily distorted. However, specific gravity is considered as an anisotropic material. It is said that the specific strength is stronger than steel. In particular, since it is a warmer material than the artificial materials used in recent years, it has been used since ancient times in areas where people are in direct contact with houses, and such woody materials have recently been reviewed.

[0003] However, the above-mentioned disadvantages of wood are difficult to replace with industrial materials. To address this, various techniques have been used to enhance the functionality of wood. Among them, the most widely used technique is a composite technique of wood and other wood.

[0004] As another method for improving the functionality of wood,
There is a composite method of depositing an inorganic substance in a porous body of wood. This method is roughly classified into the following three methods.

[0005] A method in which finely divided inorganic material is filled into a porous body by suction or pressurization.

[0006] A method of impregnating a solution in which an inorganic material to be precipitated in a porous body is dissolved in an ionic state in advance, and then volatilizing only the solvent in the solution by an external operation to deposit the inorganic material.

A method of alternately impregnating two or more solutions having the property of precipitating an inorganic material by mixing the solutions to promote a precipitation reaction in a porous body.

[0008] Focusing on the composite of wood and inorganic materials,
Barium chloride aqueous solution and ammonium hydrogen phosphate aqueous solution are sequentially injected into the wood to deposit barium hydrogen phosphate in the wood, or a metal alkoxide such as TEOS or TPOT is injected into the wood to produce silica gel. is there.

[0009]

As described above, when compounding wood with an inorganic substance, the wood is generally impregnated with a reaction liquid sequentially by a two-liquid impregnation method, and the first liquid and the second liquid are impregnated.
A method of depositing and generating an inorganic substance by a chemical reaction between ions contained in the first liquid and ions contained in the second liquid at a contact point of the liquid has been adopted. However, the compounding method based on the two-liquid impregnation method applies to products that are long in the fiber direction because products at the contact point block the diffusion path of the liquid inside the wood, preventing uniform deposition reaction. Is difficult. Therefore, as a means that has been put into practical use, only a single-plate-shaped wood having a short length in the fiber direction is targeted (for example, Japanese Patent Publication No. 2-60735).

Further, since two kinds of solutions are impregnated in wood, the impregnation operation needs to be performed twice, and there is a problem that the complexing process is complicated and complicated work is required.

Accordingly, the present invention makes it possible to uniformly combine even long wood in the fiber direction, and to simplify the operation steps required for the combination to make the inorganic composite in the porous body which does not require complicated work. The purpose is to obtain a chemical conversion method.

[0012]

According to the present invention, in order to achieve the above object, a porous body is charged into a pressure vessel, and a single solution whose pH and concentration are adjusted is injected and impregnated. And an inorganic composite method in which an inorganic substance is precipitated by operating pressure and temperature.

As a specific method, the porous body is sealed in a pressure vessel, the pressure inside the pressure vessel is reduced by a vacuum pump to a certain degree of vacuum, and then a solution whose pH and temperature have been adjusted is injected from a valve of the pressure vessel. After the pressure inside the pressure vessel is raised to the atmospheric pressure, carbon dioxide gas is injected from the valve and maintained at a constant pressure for a certain time, and then the temperature inside the pressure vessel is increased by external heating. Ascending, a precipitation reaction of the inorganic material inside the porous body is performed.

[0014] Only one type of the solution is used, and the gas injected from the outside after impregnating the porous body is diffused into the impregnated solution by a pressure operation and a temperature operation to promote the precipitation reaction of the inorganic material. .

As the solution for impregnating the inside of the porous material, an aqueous solution in which alkanolamine and calcium nitrate are mixed at a molar ratio of 2: 1 is used. Further, an alkaline earth metal carbonate is used as the inorganic material.

According to the method for forming an inorganic composite material in a porous material, a high-pressure carbon dioxide gas is injected into a solution impregnated in the porous material, whereby carbonate ions necessary for precipitation of alkaline earth metal carbonate are dissolved in the solution. And by further heating, the alkaline earth metal and the carbonate ion in the solution are combined to precipitate the alkaline earth metal carbonate.

The obtained wood is more uniformly compounded in the fiber direction than wood obtained by the conventional two-liquid impregnation method, and is effective as a method of compounding wood and inorganic materials.
Further, wood specimens prepared by the inorganic composite technology of the present invention are subjected to JIS. A. As a result of the surface burning test specified in 1321, flame-retardant wood satisfying the flame retardant class 3 was obtained.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Various embodiments of the method for forming an inorganic composite in a porous material according to the present invention will be described below. The feature of the present invention is that the porous body is impregnated with a single solution, and a gas is used as a fluid for initiating a precipitation reaction of the inorganic substance.
An inorganic compounding technique capable of simplifying a compounding step and performing uniform compounding by advancing a precipitation reaction by a temperature operation.

First, the porous body to be compounded is put into a pressure vessel such as an autoclave and sealed, and the pressure inside the pressure vessel is reduced by a vacuum pump. After a certain degree of vacuum is reached in the pressure vessel, a solution whose pH and temperature have been adjusted in advance is injected from a valve provided in the pressure vessel to impregnate the porous body. After the pressure inside the pressure vessel rises to the atmospheric pressure, carbon dioxide gas is injected from the above-mentioned valve and kept at a constant pressure for a certain time.

Thereafter, the operation is characterized by increasing the temperature inside the pressure vessel by external heating to promote the precipitation reaction of the inorganic material inside the porous body.

By injecting a high-pressure carbon dioxide gas from the outside into the solution impregnated in the porous body as described above, carbonate ions required for precipitation of the alkaline earth metal carbonate are supplied into the solution. Then, by heating from the outside, the alkaline earth metal and the carbonate ion in the solution are combined to precipitate the alkaline earth metal carbonate.

In this embodiment, monoethanolamine (hereinafter abbreviated as MEA) used for adsorption of carbon dioxide in a thermal power plant is used as the impregnating liquid, so that waste can be used and carbon dioxide can be reduced. Can be.

The specific process of complexation will be described. MEA is added to a calcium nitrate solution, and pH is adjusted with carbon dioxide gas.
Wood was impregnated with the adjusted solution by the Vessel method, and a short-lived carbon dioxide gas was supplied into the wood in a high-pressure carbon dioxide atmosphere in an autoclave to promote a precipitation reaction.

In the present embodiment, wood is selected as the porous body, and MEA and calcium nitrate are used as the impregnating liquid in a ratio of 2: 1.
(Ca ² +: 1 mol / l)
The test piece was impregnated into the test piece using, and carbon dioxide gas was injected from the outside to deposit calcium carbonate.

An actual example of the compounding step will be described with reference to the chart of FIG. First, in step 100, the cedar wood as the wood used as the porous body is dried, and in step 101, the cedar wood is charged into a pressure-resistant container, which is hermetically closed, and is evacuated by a vacuum pump.

In parallel with the above, the concentration of the solution is adjusted in step 200, and the pH and temperature of the solution are adjusted in step 201. Further, in step 202, an impregnating liquid composed of a calcium nitrate-MEA mixed liquid is mixed.

Next, an impregnating liquid is injected from a valve into the pressure-resistant container brought into a reduced pressure state in step 101 to impregnate the cedar material.

Then, after the pressure inside the pressure vessel rises to the atmospheric pressure, high pressure carbon dioxide gas CO ₂ is injected from the valve in step 103, and the pressure is maintained at a constant pressure for a certain time.

Next, in step 104, the temperature inside the pressure vessel is raised by heating, and the inorganic material C
Accelerates aCO ₃ precipitation reaction.

At step 105, the cedar material is taken out of the pressure vessel, the by-product salt is washed, and then dried at step 106. Then, the process returns to step 101, where the cedar material is again put into the pressure vessel, and the pressure is reduced by a vacuum pump. And the following steps are repeated.

By injecting a high-pressure carbon dioxide gas from the outside into the solution impregnated into the cedar material as a porous material, carbonate ions necessary for the precipitation of alkaline earth metal carbonate are dissolved in the solution. When the alkaline earth metal and the carbonate ion in the solution are supplied and heated from the outside, the alkaline earth metal and the carbonate ion combine to precipitate the alkaline earth metal carbonate.

Supplementing the description based on the chart of FIG. 1, the operation of impregnating cedar wood with the mixed solution of calcium nitrate and MEA was carried out by the Vessel method under reduced pressure and increased pressure. A test piece (fiber direction: 100 mm, radial direction: 30 mm, tangential direction: 30 mm) was set in an autoclave, and a decompression operation was performed for about 12 hours by a vacuum pump using a combined decompression and pressurization valve (step 101), and then mixed. The solution is injected until the inside of the autoclave reaches atmospheric pressure (step 10).
2) After that, a pressurizing operation was performed for 2 hours at a pressure of 0.59 MPa by a compressor using a combined pressure-reducing and pressure-applying valve.

Next, the pressure inside the autoclave is returned to the atmospheric pressure, and carbon dioxide gas CO ₂ is supplied from the combined pressure-reduction / pressure valve.
By press-fitting with a pressure of 08 MPa (step 103) and holding for a certain period of time, carbon dioxide was dissolved and diffused in the solution impregnated in the test piece.

Next, heating was carried out by a band heater installed outside the autoclave, and CaC was kept at 80 ° C. for one hour.
An O ₃ precipitation reaction operation was performed (step 104).

After completion of the precipitation reaction, the wood was taken out of the autoclave and immersed in flowing hot water at 60 ° C. for 24 hours to dissolve and wash HO (CH ₂ ) ₂ NH ₃ NO _{3 as a} by-product salt (Step 105).

The cedar wood thus obtained is the same as the conventional cedar wood.
In order to demonstrate that it is more uniformly compounded in the fiber direction than wood obtained by the liquid impregnation method, the precipitation state of calcium carbonate inside the obtained compounded wood was equidistant from the fiber direction of the wood. 5 places, tangential direction 30mm,
A test piece 30 mm in radial direction and 5 mm in fiber direction was cut out and burned in an electric furnace at 1000 ° C. Dissolve the remaining ash with hydrochloric acid, adjust the pH with potassium hydroxide,
The calcium ions were titrated by EDTA, and the distribution of calcium carbonate in the fiber direction was quantitatively measured.

FIG. 2 is a graph showing the weight ratio (%) of calcium carbonate to the distance (mm) from the center of the test piece in the fiber direction, that is, the distribution of calcium carbonate. FIG. The weight ratio of calcium carbonate to the material was about 60% on average, and the distribution of the weight ratio of calcium carbonate to the fiber direction tended to be lower at the center. However, even in the central part where the weight ratio of calcium carbonate was the lowest, the weight ratio was about 50%, demonstrating that it was effective as a method of combining wood and inorganic materials.

Next, a cedar material having a fiber direction of the test piece of 210 mm, a tangential direction of 210 mm, and a radial direction of 15 mm was subjected to inorganic compounding with calcium carbonate by the same operation as described above, and the JIS. A. A surface combustion test was performed in accordance with 1321 “Test method for flame retardancy of building interior materials and construction methods”. FIG. 3 shows the relationship between time (second) and exhaust temperature (° C.), and FIG. 4 shows time (second) and light amount (%).
Shows the relationship.

Judgment of flammability is based on "flame retardancy test method for building interior materials and construction methods" JIS. A. 1321. From the exhaust gas temperature curve and the smoke emission coefficient obtained from the combustion test results, the first, second, and third flammability classes are determined. The following are the criteria for the 3rd grade of flame retardant.

(1) No melting of the test piece over its entire thickness, no crack on the back surface of the test piece, and no other remarkable harmful deformation on fire prevention. (2) There should be no residual flame for at least 30 seconds after the end of heating. (3) The exhaust temperature curve of the test result is
Do not exceed the standard temperature curve. However, with regard to flame retardant class 2 or flame retardant class 3, after 3 minutes have passed since the start of the test, it can be exceeded within the range of the following condition (4).

(4) If the area of the exhaust temperature curve where the exhaust temperature curve exceeds the standard temperature curve and the area surrounded by the standard temperature curve (unit: ° C × min) is the second-class flame retardant, 10
0 or less, and 350 or less for flame retardant class 3.

(5) The smoke emission coefficient (CA) per unit area determined by the equation (1) should not exceed the numerical value in Table 1 according to the flame retardancy class. CA = 240 log ₁₀ (I ₀ / I) (1) where I ₀ is the light intensity (IX) at the start of the heating test and I
Is the minimum light intensity (IX) during the heating test.

[0043]

[Table 1]

From the above determination, the test piece prepared by the inorganic composite technique was evaluated for flame retardancy, and as a result, it was found that the test piece satisfied the flame retardant class 3.

[0045]

As described above in detail, according to the method for forming an inorganic composite in a porous material according to the present invention, a high-pressure carbon dioxide gas is injected into a solution impregnated in the porous material to thereby form an alkaline earth metal. Carbonate necessary for the precipitation of the carbonate is supplied into the solution, and by heating, the alkaline earth metal and the carbonate ion in the solution are combined to precipitate the carbonate of the alkaline earth metal.

In particular, unlike the conventional two-liquid impregnation method, which is a method of compounding wood with an inorganic substance, there is no need to impregnate the wood with two kinds of solutions and it is not necessary to perform the impregnation operation twice.
In addition to simplifying the process, the compounding method using the two-liquid impregnation method is such that the product at the contact point blocks the diffusion path of the liquid inside the wood, hinders a uniform precipitation reaction, and is long in the fiber direction. However, in the case of the present invention, there is a great effect that it is possible to form a uniform composite even for wood that is long in the fiber direction.

Further, the wood made by the inorganic composite technology of the present invention satisfies the third grade of flame retardancy of the surface combustion test specified in the JIS standard, so that the wood for home use can be highly functionalized. By increasing the decay property, flammability, and dimensional stability, the utility value as an industrial material can be increased.

[Brief description of the drawings]

FIG. 1 is a chart showing a practical example of a composite process in a porous body of the present invention.

FIG. 2 is a graph showing the distribution of calcium carbonate in a test piece obtained according to the present invention.

FIG. 3 is a time (second) when a surface burning test of a test piece is performed.
4 is a graph showing the relationship between the temperature and the exhaust temperature (° C.).

FIG. 4 is a time (second) when a surface burning test of a test piece is performed.
7 is a graph showing the relationship between the light amount and the light amount (%).

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Kensuke Yamazaki 3992-3, Fushida, Kochi City, Kochi Prefecture Inside the Kochi Prefectural Industrial Technology Center (72) Inventor Hideto Yoshinaga 3240 Ino, Nankoku City, Kochi Prefecture (72) Inventor Yamazaki Nakamichi 107 Koga, Sagawa-cho, Takaoka-gun, Kochi Prefecture

Claims (6)

[Claims] 1. A porous body is charged into a pressure vessel, a single solution of which pH and concentration are adjusted is injected and impregnated, and then a gas is injected to deposit an inorganic substance by operating pressure and temperature. And a method of compounding an inorganic substance in a porous body. 2. After sealing the porous body in a pressure vessel and reducing the pressure inside the pressure vessel by a vacuum pump to a certain degree of vacuum,
The pH and temperature-adjusted solution is injected from the valve of the pressure vessel to impregnate the wood, the pressure inside the pressure vessel is raised to atmospheric pressure, and then carbon dioxide gas is injected from the valve and kept at a constant pressure for a fixed time. And then performing a precipitation reaction of the inorganic material inside the porous body by increasing the temperature inside the pressure vessel by heating from the outside, and performing an inorganic composite method on the porous body. 3. The solution is impregnated in a porous body using only one kind of gas, and a gas injected from the outside is diffused into the impregnated solution by a pressure operation and a temperature operation to promote a precipitation reaction of an inorganic material. The inorganic composite method for a porous body according to claim 1 or 2, wherein: 4. An inorganic material in a porous body according to claim 1, wherein an aqueous solution obtained by mixing alkanolamine and calcium nitrate at a molar ratio of 2: 1 is used as the solution for impregnating the inside of the porous body. Composite method. 5. The method according to claim 1, wherein an alkaline earth metal carbonate is used as the inorganic material. 6. A high-pressure carbon dioxide gas is injected into the solution impregnated in the porous body to supply carbonate ions necessary for the precipitation of carbonate of alkaline earth metal into the solution and further heat from the outside. 6. The inorganic composite in a porous body according to claim 1, wherein the alkaline earth metal in the solution is combined with carbonate ions to precipitate a carbonate of the alkaline earth metal. Method.