JP2000247722A - Flame-retardant board and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively obtain a board having excellent heat resistance, flame retardance and soundproofing properties, not emitting a toxic gas by formulating a powder mixture having a specific composition composed of a vegetable fiber, inorganic powder, an acid and a coloring matter with an aqueous solution of sodium metasilicate, kneading, molding the mixture under pressure and drying. SOLUTION: A vegetable fiber of powder raw material in an amount of 15-60% is sufficiently formulated with 5-30% of inorganic powder of functional material, 2-10% of an acid and about 2.5% of a coloring matter. The vegetable fiber is preferably a cellulose having 10-300 μm diameter and 30-300 μm length. The inorganic powder is preferably a metal oxide having 0.3-300 μm diameter and natural stone named Hanmokustone, or the like, are used. An acid having 0.5-1,000 μm is used. The powder mixture is kneaded with an aqueous solution of sodium metasilicate and uniformly dispersed. The aqueous solution of sodium metasilicate is obtained by adding 5-80% of sodium metasilicate to water and mixing. The kneaded material is molded under pressure and dried to give the objective high-strength flame-retardant board.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame-retardant board used for a wide range of uses such as a heat insulating material and a fitting material, and a method for producing the same.

[0002]

2. Description of the Related Art Insulating materials using foamed plastics, resin materials, glass wool, and the like have recently been used in place of asbestos that directly affects the human body. It is mixed as.

[0003]

Although foamed plastics and resin materials as general heat insulating materials have high flame retardancy, they have a problem that toxic gas with an unpleasant odor is generated at the time of fire due to organic substances. On the other hand, glass wool does not generate toxic gas and is excellent as a flame retardant.However, since glass is stretched into a fibrous form, it is necessary to pack it into bags at the time of construction. However, there are disadvantages in that the handling is extremely inconvenient because the materials are piled up and material costs are high. Lime, which is calcium carbonate, is rarely used except for flame retardants for concrete.

The present invention has been made in view of the above-mentioned conventional circumstances, and is excellent in heat resistance, flame retardancy and soundproofing, does not generate toxic gas, and is used not only as a heat insulating material but also as a building material and as a furniture fitting. Can be used for a wide range of applications,
It is an object of the present invention to provide a flame-retardant board which can be obtained at low cost and a method for producing the board.

[0005]

Accordingly, the present invention provides 15 to 60% of vegetable fiber as a powder raw material, 5 to 30% of an inorganic powder as a functional material, 2 to 10% of an acid, and 2.5% of a pigment. The main object is a flame-retardant board formed by adding a 5 to 80% sodium metasilicate aqueous solution of sodium metasilicate to a powder mixture consisting of a mixture and pressing and drying the mixture.

As a production method therefor, 15 to 60% of vegetable fiber having a diameter of 10 to 300 μm and a length of 50 to 3000 μm as a powder raw material, and a diameter of 0.3 to 300 μm as a functional material
5 to 30%, 0.5 to 1 of an inorganic powder which is a metal oxide of m
A powder mixture is formed by thoroughly mixing 2 to 10% of an acid of 000 μm and about 2.5% of a pigment, and 5 to 80% of sodium metasilicate as a liquid material is added to water and mixed to form an aqueous solution of sodium metasilicate. And a step of adding an aqueous solution of sodium metasilicate to the powder mixture, kneading and uniformly dispersing the mixture, and pressing and molding the kneaded mixture, followed by drying.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Vegetable fibers, ie, cellulose fibers, are 40% (diameter is about 100 μm and length is about 1000 μm), and metal oxide particles of inorganic powder are 20% (diameter 100 μm).
m), 5% acid (about 500 μm), 2.5% dye
Mixing and kneading the mixture into a powder mixture, and adding and mixing an aqueous solution of sodium metasilicate obtained by mixing sodium metasilicate, which is a liquid raw material of 30% or more, with water; Then, the flame-retardant board of the present invention is formed through a step of drying after pressure molding. In addition, as a metal oxide, 84% of SiO ₂ and Al ₂ O ₃ 8
%, Fe ₂ O _3, 0.76%, etc., which are commonly used as natural products.

[0008]

EXAMPLES (Kneading step) The fibrillated cellulose fibers 1 absorb the uniformly dispersed moisture while being entangled with each other, and undergo hydrogen bonding between the OH groups of the cellulose fibers and water molecules H ₂ O between the fibers. (See FIGS. 1 and 2 (a) and 2 (b)).

Cellulose fibers 1 bonded by hydrogen bonds mediated by water molecules form a chain and three-dimensional network structure, and disperse metal oxide particles (inorganic powder 2) in FIG. (B) As shown in (b), the inorganic powder 2 trapped in the cavities between the fibers or dispersed on the surface of the fibers is covered with sodium metasilicate, and the sodium metasilicate is insoluble in acid by the acid. (FIG. 3C, FIG. 4A, FIG. 4B)
(C)).

The liquid sodium metasilicate aqueous solution covers the surface of the fiber and forms a coating (see FIG. 4 (c)). The sodium metasilicate soaked into the pores 4 inside the fiber and the cavity 5 between the fibers reacts with the acid to form an insoluble metasilicate gel 3, and the formation of an integrated skeleton of a chain-like and three-dimensional network structure proceeds. (See FIGS. 4A, 4B, and 4C).

(Pressurizing step) The kneaded material is pressed into a predetermined shape to form a material between the materials of the kneaded material (fibers, fiber and sodium metasilicate, fiber-inorganic powder-sodium metasilicate). Reduces existing cavities and increases adhesion. As a result, the bonding force such as hydrogen bonding between the fibers and the bonding force between the respective substances are increased, and a predetermined shape is formed.

(Drying step) After the pressure molding, the moisture is evaporated by drying. The water between the cellulose fibers 1 also evaporates, and the hydrogen bond between the fiber and water disappears. Instead, the fibers are newly bonded to each other by the OH group of the cellulose fibers due to the strong bonding force of the hydrogen bond between the fibers. To form a skeleton of a paperboard with a chain-like, three-dimensional network structure (Fig. 2
(C), see FIGS. 1 and 2 (b)).

On the other hand, the sodium metasilicate impregnated into the pores 4 of the fiber and the cavity 5 between the fibers reacts with the acid, so that Na ⁺ ions in the sodium metasilicate react with the acid, and Na ⁺
Instead of removing the ions, the H ⁺ ions of the acid are replaced to form an insoluble metasilicate gel 3. When moisture evaporates during the drying operation, the metasilicate gel 3 solidified in the pores 4 of the fiber is strongly bound to the fiber, and the metasilicate gel covering the voids and the surface between the fibers has a chain-like, three-dimensional structure. Is formed, solidified and strongly bound between the fibers, and does not peel off, further increasing the strength of the paper board (see FIGS. 4 (a), (b) and (c)).

A metal oxide (inorganic powder 2) as a functional material is mixed with other raw materials and uniformly dispersed, and a part of the metal oxide is trapped inside the fiber, and a part of the metal oxide is formed on the fiber surface by the metasilicate gel 3. It can be integrated with a paper board without being caught and peeled off, and each function of the inorganic powder is exhibited (Fig. 3
(A), (b), (c) and FIGS. 5 (a), (b).

[0015]

As described above, the present invention has the following various effects. 1. The silica gel formed by the sodium silicate chemically reacting with the acid covers the fiber surface with a thin film, and the inorganic powder of the functional material is also trapped in the fiber surface and in the cavities of the network structure, and around the fiber. Are arranged. Cellulose fibers are insoluble and are surrounded by a metasilicate gel having a melting point of about 1000 degrees and an inorganic powder as a metal oxide. Therefore, the fibers are not easily burnt and do not ignite. Among the raw materials, the hydrocarbon-based material is only fiber, and all other raw materials are inorganic powders and inorganic materials of metal oxides that do not burn,
The fiber part is covered with a coating of inorganic material, and the surrounding fiber part has a low oxygen content, so the integrated board shows heat resistance properties, and it is a flame retardant paper board. It becomes a fire prevention board that does not ignite. 2. The metasilicate gel solidifies in such a manner that it wraps the cellulose fibers in the voids between the fibers, the surface of the fibers, and the pores of the fibers, and binds strongly to the cellulose fibers. The metasilicate gel itself also forms a skeleton with a three-dimensional network structure. That is, an integrated composite board having strong strength is obtained by the bonding force of the cellulose fibers by the strong hydrogen bond and the bonding force of the silicate gel. 3. Cellulose fiber structure forming a three-dimensional structure,
By adjusting the structure of the metasilicate gel and the porosity of the board can be adjusted, and by adjusting the porosity to a large value, a board having a large soundproofing effect can be obtained. 4. Cellulose fiber is also a porous network structure,
The OH groups of the cellulose fibers are likely to combine with highly polar water in the air. Focusing on this hygroscopicity, dew condensation can be prevented when used as a building material. In addition, since the skeleton of the board is composed of cellulose fibers and an insoluble metasilicate gel, even if the hydrogen bond of the cellulose fibers is broken by water when absorbing moisture, the paper board is separated due to the structure of the metasilicate gel. It will not be. 5. Because the cellulose fiber and the metasilicate gel have a network structure, the fiber has many pores, and the structure of the metasilicate gel is negatively charged, the composite material board has gas absorption, Has adsorptive properties. In addition, since the inorganic powder and the metal oxide (porphyry stone) can be uniformly contained in the board, the composite board exhibits an adsorbing property of an acidic gas and an alkaline gas such as hydrogen sulfide and ammonia gas which the metal oxide has. 6. Since gabbro can be integrated into the board as a functional material,
Can exhibit antibacterial and antifungal properties due to gabbro. 7. Since porphyry stone, titanium oxide, zirconium oxide, aluminum oxide, silicon oxide, and iron oxide can be integrated into the board as a functional material, a composite board exhibiting characteristics of 8 to 20 μm far-infrared radiation is obtained. 8. Since the porphyry stone can be integrated with the board, a paper board having the property of emitting negative ions can be obtained. 9. Since it is a porous, heat-resistant and non-ignitable composite material, it can be used as a heat insulating material. 10. Even if the building material is burned by fire or the like and carbon dioxide is generated from other substances, the structure of the cellulose fiber and the metasilicate gel is not damaged by carbon dioxide, and the strength is not deteriorated. On the other hand, in sodium metasilicate, sodium ions are combined with carbon dioxide to change to sodium carbonate, and a heat-resistant insoluble metasilicate gel is simultaneously formed. Increase its strength. 11. The nail can be hit, and it can be cut with a saw or the like like wood.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a three-dimensional structure in which cellulose fibers are hydrogen-bonded.

FIGS. 2 (a), (b) and (c) are explanatory views showing a process of changing a hydrogen bond chemical formula of a cellulose fiber in a flow chart.

FIGS. 3A and 3B are explanatory diagrams showing a state of capturing fibers of an inorganic powder, wherein FIG. 3A shows a three-dimensional network structure, FIG. 3B shows an enlarged inorganic powder, and FIG. 3C shows a network structure of a metasilicate gel. .

4A and 4B show a bond between a fiber and a metasilicate gel, wherein FIG. 4A is a diagram illustrating inorganic powder and fine pores of a fiber, FIG. 4B is a diagram illustrating a cavity of a fiber, and FIG.

FIGS. 5A and 5B are explanatory diagrams of the structure of a three-dimensional silicate gel network and inorganic powder, and FIG. 5A is an overall view and FIG. 5B is a partial view.

[Explanation of symbols]

 1 fiber 2 inorganic powder

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) C04B 22:08 14:02) 111: 12 F term (Reference) 2E001 DD01 DD05 DE01 DF01 FA00 GA03 HC11 JA06 JC03 2E162 CC00 FA00 FC02 4G012 PA11 PA24 PB06 PE03

Claims (2)

[Claims] 1 to 15% by weight of a vegetable fiber as a powder raw material;
A kneaded product formed by adding a sodium metasilicate aqueous solution of 5 to 80% sodium metasilicate to a powder mixture composed of about 5 to 30% of inorganic powder as a functional material, about 2 to 10% of acid, and about 2.5% of pigment. Flame-retardant board formed by pressing and drying. 2. A powder raw material having a diameter of 10 to 300 .mu.m and a length of 50 to 3000 .mu.m, a vegetable fiber of 15 to 60%, and a functional material of a metal oxide having a diameter of 0.3 to 300 .mu.m, an inorganic powder of 5 to 30%. 2 to 10% of 0.5 to 1000 μm acid,
About 2.5% of pigment is mixed well to form a powder mixture,
A liquid raw material, sodium metasilicate, of 5 to 80% is added to water and mixed to form an aqueous sodium metasilicate solution. An aqueous sodium metasilicate solution is added to the powder mixture, kneaded and uniformly dispersed, and the kneaded mixture is added. A method for producing a flame-retardant board, comprising the steps of pressing and drying.