JP5432115B2 - Manufacturing method of wood-based molded body - Google Patents

Description

The present invention relates to a method for producing a wood-based molded body having high fire resistance.

  Fireproofing agents such as phosphorus compounds, nitrogen compounds, and boron compounds as methods for imparting fireproofing and antproofing properties to woody materials such as wood fibers, cellulose fibers, wood chips, wood particles, wood fragments, wheat straw, and rice straw Is used.

  For example, JP-A-2005-112700 (Patent Document 1) discloses a high-concentration aqueous solution of 2.5 mol / kg or more in terms of boron by dissolving boric acid and sodium borate (borax) at a predetermined ratio. A technique for imparting fire resistance to wood by treating the wood with such an aqueous solution is disclosed. However, in such a technique, there is a problem that the impregnation property of the boron compound into the wood or the like is low, and the surface layer of the wood or the like becomes white and easily eluted.

JP 2003-226877 A (Patent Document 2) discloses ammonium sulfate, primary ammonium phosphate (monoammonium phosphate, NH ₄ H ₂ PO ₃ ), dibasic ammonium phosphate (diammonium phosphate, (NH ₄ ) By treating the wood-based material with an aqueous solution containing at least one compound of ₂ HPO ₃ ), ammonium borate, sodium borate and boric acid, and a fixing compound, the wood-based material is provided with fire resistance. The technology to do is disclosed. However, in such a technique, the concentration of the compound in the aqueous solution cited as an example is as low as about 13 to 17% by mass, and the treatment time for impregnating and drying the aqueous solution in the wood material is long. There was a problem that the fire resistance provided was low.

  Japanese Patent Laying-Open No. 2005-212342 (Patent Document 3) discloses a technique for producing a modified wood board by treating a wood material with a mixed aqueous solution of a phosphoric acid compound and a boric acid compound and then forming a board. However, in such a technique, the concentration of the phosphoric acid compound and boric acid compound in the mixed solution is as low as about 20% by mass, and the treatment time for impregnating and drying the aqueous material into the woody material is long and fire protection is provided. There was a problem of low nature.

  Japanese Patent Laid-Open No. 6-254817 (Patent Document 4) treats wood fibers with a treatment liquid obtained by adding and mixing aluminum hydroxide into an aqueous solution in which phosphate and borate are dissolved. Thereafter, a technique for producing a modified wood fiber board by forming into a board by molding is disclosed. However, in such a technique, the concentration of the non-combustible compound in the above-mentioned treatment liquid cited as an example is such that the concentration of phosphate (diammonium phosphate) is 3 mol / l, and the concentration of borate (sodium borate). Is as low as 0.2 mol / l and aluminum hydroxide is as low as 25 g / l, and there is a problem that the treatment time for impregnating and drying the above aqueous solution into the wood fiber is long.

  Moreover, JP 2009-113258 A (Patent Document 5) discloses that at least one of ammonium carbonate and ammonium hydrogen carbonate as a boron-based agent that promotes dissolution of a non-combustible agent by gasification into water by heating, and a boron-based agent. Disclosed is a technique for imparting fire resistance to a wood material by treating the wood material with an incombustible agent in which at least one of an incombustible agent and a phosphate-based incombustible agent is dissolved. However, in such a technique, the above ammonium-based chemicals are decomposed by heating at a low temperature of about 60 ° C., so that an ammonia odor is generated during the heat treatment and the working environment is extremely deteriorated. There are problems such as.

    In addition, Shinichi Kikuchi, Katsumi Komazawa, surface flammability of flame retardant treated wood fiber, Forest Products Experiment Station Bulletin, Hokkaido Forest Products Laboratory, 1999, Vol. 13, No. 5, pages 7-13 (Non-Patent Document 1) It is disclosed that the fire resistance of wood fibers treated with various flame retardants of dibasic ammonium phosphate, ammonium sulfate or sodium octaborate was evaluated by a surface combustion test. However, this research report is a comparative study of the fire resistance of wood fibers treated with various flame retardants, and has not led to a comprehensive evaluation of fire resistance when using multiple flame retardants of these types. .

JP 2005-112700 A JP 2003-226877 A JP 2005-212342 A JP-A-6-254817 JP 2009-113258 A

Shinichi Kikuchi, Katsumi Komazawa, “Surface Combustibility of Flame Retardant Wood Fiber”, Forest Products Experiment Station Report, Hokkaido Forest Products Experiment Station, 1999, Vol. 13, No. 5, pages 7-13

In order to solve the above problems, the present invention prepares a solution having a high concentration of fireproofing agent using a dissolution aid that does not elute from the wood-based material and does not gasify by low-temperature heating, and is treated with the solution. An object of the present invention is to provide a method for producing a wood-based molded body having high fire resistance by molding a wood-based material.

  That is, the present invention uses ammonium sulfate as a fireproofing agent as a solubilizing agent for borate and condensed ammonium phosphate as a fireproofing agent, that is, in an ammonium sulfate aqueous solution obtained by first dissolving ammonium sulfate in water, Next, by dissolving borate and then dissolving condensed ammonium phosphate, at least 40% by mass of condensed ammonium phosphate and 20% by mass or more of borate are dissolved at room temperature (for example, 25 ° C.). Found that a high-concentration fire-prevention chemical solution having a concentration of fire-prevention chemicals (condensed ammonium phosphate, borate and ammonium sulfate) of 40% by mass or more can be obtained, and treated with such a high-concentration fire-prevention chemical solution By molding a system material, a wood-based molded body having high fire resistance is provided. Specifically, the present invention is as follows.

The present invention relates to at least one woody material selected from the group consisting of wood fiber, cellulose fiber, wood chip, wood particle, wood piece, wheat straw and rice straw in an amount of 60 parts by weight or more and 90 parts by weight or less, ammonium sulfate, borate and A fireproofing step for adding a fireproofing chemical solution containing condensed ammonium phosphate in an amount of 5 to 35 parts by weight of the fireproofing chemical component, and drying the wood-based material to which the fireproofing chemical solution was added, and a fireproofing treatment were performed. A mixing step of mixing a wood-based material and at least one of a fibrous adhesive and a liquid adhesive in an amount of 5 parts by mass or more and 15 parts by mass or less, and a mixture obtained by mixing is accumulated in a mat shape; includes a molding step of obtaining a density 40 kg / m ³ or more wooden moldings by heat and pressure molded into board form, the production of fire protection agent is water A first sub-step for dissolving ammonium acid to obtain an aqueous ammonium sulfate solution, a second sub-step for obtaining an ammonium sulfate-borate aqueous solution by dissolving borate in the aqueous ammonium sulfate solution at a concentration higher than the solubility in water, and ammonium sulfate-boron And a third sub-step for obtaining an ammonium sulfate-borate-condensed ammonium phosphate aqueous solution by dissolving condensed ammonium phosphate in the acid salt aqueous solution.

In the method for producing a wood-based molded body according to the present invention, the wood-based molded body obtained in the above step is further heated and pressed to obtain a wood-based molded body having a density of 150 kg / m ³ or more. The method may further include a molding process.

According to the present invention, an ammonium sulfate that does not elute from a wood-based material and is not gasified by low-temperature heating is used as a dissolution aid, and a fire-protecting chemical solution having a high concentration of condensed ammonium phosphate, borate, and ammonium sulfate as a fire-proofing agent is obtained. By preparing and molding a wood-based material treated with such a fire-proofing chemical solution, it is possible to provide a method for producing a wood-based molded body having a high fire resistance.

[Embodiment 1]
The wood-based molded product according to one embodiment of the present invention has 60 parts by mass or more of at least one wood-based material selected from the group consisting of wood fibers, cellulose fibers, wood chips, wood particles, wood pieces, wheat straw and rice straw. 5 parts by mass or more and 35 parts by mass or less of a fireproofing agent containing ammonium sulfate, borate and condensed ammonium phosphate, and 5 parts by mass or more of at least one adhesive of a fibrous adhesive and a liquid adhesive. The density is 40 kg / m ³ or more. Such a wood-based molded article has high fire resistance since it contains 5 parts by mass or more and 35 parts by mass or less of ammonium sulfate, borate, and condensed ammonium phosphate as fire retardants.

(Woody material)
The wood-based material contained in the wood-based molded body of this embodiment is at least one selected from the group consisting of wood fibers, cellulose fibers, wood chips, wood particles, wood pieces, wheat straw, and rice straw. Such a wood-based material has high moldability, and is therefore suitable as a material for a wood-based molded body. Here, the wood fiber is a fiber obtained by steaming and defibrating at least one of coniferous and hardwood, and there is no particular limitation, but from the viewpoint of high moldability, the average fiber diameter is 3 mm or less, the average fiber length Is preferably 20 mm or less. Cellulose fiber is a fiber having cellulose molecules linked in a straight line, and is not particularly limited, but is a fiber obtained from at least one of kraft pulp, recycled pulp and waste paper from the viewpoint of easy mass acquisition. It is preferable. The wood chip is not particularly limited as long as it is a chip of at least one of softwood and hardwood. The wood particle is obtained by crushing the wood chip and is not particularly limited, but the average particle size is preferably 5 mm or less. The wood piece is a small piece of at least one of softwood and hardwood, and there is no particular limitation, but from the viewpoint of high moldability, it is a polygonal plate shape, the maximum side length is 30 mm or less, and the thickness is 5 mm or less. Is preferred. The wheat straw and / or rice straw is wheat and / or rice straw, and is not particularly limited. From the viewpoint of high moldability, it has a flat shape, a maximum length of 30 mm or less, and a thickness after molding of 5 mm. The following is preferable.

  Further, the number of parts of the wood-based material contained in the wood-based molded body of the present embodiment is 60 parts by mass or more and 90 parts by mass or less, and preferably 60 parts by mass or more and 85 parts by mass or less from the viewpoint of high formability.

(Fire protection agent)
The fireproofing agent contained in the woody molded product of the present embodiment is ammonium sulfate, borate and condensed ammonium phosphate. Here, ammonium sulfate is a fireproofing agent that imparts fireproofing properties to the wood-based material, and a dissolution aid that increases the solubility of borate and improves the dissolution stability of condensed ammonium phosphate when preparing a fireproofing agent solution. It is. Moreover, since ammonium sulfate has a hygroscopic property, it is also a humidity control agent which improves the hygroscopic property of the wood-based material. The borate is a fireproofing agent that imparts fireproofing properties to the wood-based material, and can enhance the shape retention of the wood-based material after combustion. The borate is not particularly limited, but from the viewpoint of easy availability, sodium tetraborate (Na ₂ B ₄ O ₇ .10H ₂ O (Na ₂ [B ₄ O ₅ (OH) ₄ ] · 8H ₂ O)), sodium octaborate (Na ₂ B ₈ O ₁₃ · 4H ₂ O) and the like are preferable. In addition, condensed ammonium phosphate has a high phosphorus content because phosphoric acid is condensed, and is an extremely excellent fireproofing agent.

  Therefore, the fireproofing agent containing ammonium sulfate, borate and condensed ammonium phosphate increases the fireproofing property of the wood-based material with ammonium sulfate, borate and condensed ammonium phosphate (especially condensed ammonium phosphate). Increases the shape retention of the wood-based material after combustion and imparts ant-proofing properties to the wood-based material, and increases the concentration of borate and condensed ammonium phosphate with ammonium sulfate to increase the fireproofing properties and humidity control of the wood-based material To increase. For this reason, fireproofing agents containing ammonium sulfate, borates and condensed ammonium phosphate provide high fireproofing properties to wood-based materials, as well as ant-proofing and humidity control properties, so A wood-based molded article excellent as a material or the like can be obtained.

  In preparing the fireproofing chemical solution, the borate may be obtained by reacting boric acid with sodium bicarbonate (also referred to as sodium bicarbonate).

  Moreover, the number of parts of the fireproofing agent contained in the wood-based molded product of this embodiment is 5 parts by mass or more and 35 parts by mass or less, and 8 parts by mass or more and 35 parts by mass or less from the viewpoint of high fireproofing properties and high moldability. 16 parts by mass or more and 35 parts by mass are more preferable.

  In addition, from the viewpoint of improving the fireproofing, antproofing and humidity control properties of the wood-based molded body of this embodiment in a well-balanced manner, in the fireproofing agent contained in the wood-based molded body, ammonium sulfate, borate and condensed ammonium phosphate As for the ratio of the number of parts of a mass part, 1-2: 2-4: 2-4 are preferable.

(adhesive)
The number of parts of at least one of the fibrous or liquid adhesive contained in the wood-based molded product of the present embodiment is 5 parts by mass or more and 15 parts by mass or less from the viewpoint of obtaining a molded product having high moldability and high strength. is there.

(Fibrous adhesive)
The fibrous adhesive contained in the wood-based molded product of the present embodiment is not particularly limited, but at least a part thereof is 90 ° C. or higher and 160 ° C. or lower from the viewpoint of obtaining a molded product with improved moldability and high strength. It has a melting point and has adhesiveness in at least one of the melting point and a hot water atmosphere of 80 ° C. or higher and 100 ° C. or lower.

  Since at least a part of the fibrous adhesive has a melting point of 90 ° C. or higher and 160 ° C. or lower, the fibrous adhesive is useful as an adhesive for woody materials by heat treatment at the melting point and higher temperature.

  Since the fibrous adhesive has adhesiveness in at least one of a melting point of 90 ° C. or higher and 160 ° C. or lower and a hot water atmosphere of 80 ° C. or higher and 100 ° C. or lower, 90 ° C. or higher and 160 ° C. or lower. Not only the melting point but also heat treatment in a hot water atmosphere at 80 ° C. or higher and 100 ° C. or lower is useful as an adhesive for woody materials. Here, the hot water atmosphere of 80 ° C. or more and 100 ° C. or less is sufficient as long as moisture exists in the range of 80 ° C. or more and 100 ° C. or less. Can swell and have adhesiveness. Examples of the fibrous adhesive having at least a part of which is swollen and has adhesive properties include polyolefin-polyvinyl alcohol fibers having a core-sheath structure, polyvinyl alcohol-polyolefin fibers having a sea-island structure, and the like. The

  The fibrous adhesive is not particularly limited, but from the viewpoint of obtaining a molded article having high moldability and high strength, at least one of an adhesive having a core-sheath structure, an adhesive having a sea-island structure, and a novolac resin adhesive is used. Preferably there is.

  The fibrous adhesive having a core-sheath structure refers to a fibrous adhesive having a core part and a sheath part covering the core part, the core part being PP (polypropylene) and the sheath part being PE (polyethylene). PP-PE fibers and other high melting point polyolefins-low melting point polyolefin fibers (where high melting point polyolefins and low melting point polyolefins are polyolefins having a relatively high melting point and polyolefins having a relatively low melting point between them). ), Polyethylene terephthalate-polyolefin fibers such as PET-PE fibers in which the core is PET (polyethylene terephthalate) and the sheath is PE (polyethylene), the core is PET and the sheath is polyethylene such as maleic acid-modified PET fibers. Terephthalate-low melting point modified polyethylene terephthalate fiber (here, low melting point modified fiber) Liethylene terephthalate refers to polyethylene terephthalate that has been chemically modified (for example, dicarboxylic acid modification) to have a lower melting point than polyethylene terephthalate. The core is made of polyolefin and the sheath is made of PVA (polyvinyl alcohol). A certain polyolefin-polyvinyl alcohol fiber etc. are illustrated suitably.

Moreover, it is preferable that the fibrous adhesive which has this core-sheath structure contains 0.5 mass% or more and 5 mass% or less of oxidative degradation promoter from a viewpoint of promoting the decomposition | disassembly after use of a wood type molded object. The oxidative decomposition accelerator is not particularly limited as long as it promotes oxidative decomposition of the fibrous adhesive in the woody molded body after use, and is a photocatalyst such as titanium dioxide (TiO ₂ ) or zinc oxide (ZnO), Preferred examples include rare earth compounds and aliphatic carboxylic acids.

  The fibrous adhesive having a sea-island structure refers to a fibrous adhesive having a cross section having at least one island part and a sea part covering the island part, where the sea part is PVA (polyvinyl alcohol) and the island part is an island part. Preferable examples include polyvinyl alcohol-polyolefin fibers which are polyolefin, and polyvinyl alcohol-polyethylene terephthalate fibers where the sea part is PVA and the island part is PET (polyethylene terephthalate). Moreover, in said polyvinyl alcohol-polyolefin fiber, it is preferable that polyolefin is biodegradable polyolefin from a viewpoint of promoting the decomposition | disassembly after use of a wood type molded object. Here, examples of the biodegradable polyolefin include polyolefins to which an oxidative degradation accelerator such as P-Life (R) (manufactured by PLife Japan) is added.

  In addition, the PVA (polyvinyl alcohol) -polyolefin fiber has a mass ratio O / V of the polyolefin portion O to the PVA portion V from the viewpoint that PVA swells in a hot water atmosphere and easily exhibits adhesiveness at a temperature below the melting point. 1 or more and 2.34 or less are preferred, and 1 or more and 1.87 or less are more preferred.

  The novolak resin fibrous adhesive is not particularly limited, but is preferably a novolak resin fiber before curing having an uncrosslinked portion from the viewpoint of obtaining a molded article having high moldability and high strength. Such novolak resin fibers are preferably exemplified by uncured novolak fibers described in Example 1 of JP-A-48-11284.

  The fibrous adhesives listed above preferably have a fineness of 4 dtex or more and 15 dtex or less and a fiber length of 20 mm or less from the viewpoint of high moldability and workability.

(Liquid adhesive)
The liquid adhesive contained in the woody molded product of the present embodiment is not particularly limited, but from the viewpoint of obtaining a molded product having high moldability and high strength, an isocyanate compound, a urethane resin, a phenol resin, a melamine resin, and a urea resin. A thermosetting resin containing at least one selected from the group consisting of Moreover, since the said compound and resin have high fire resistance, it can improve the fire resistance of a wood type molded object. Here, preferred examples of the isocyanate compound include MDI (diphenylmethane diisocyanate), polymeric MDI, TDI (toluene diisocyanate), HDI (hexamethylene diisocyanate), and the like. Moreover, as a urethane resin, the urethane prepolymer etc. with which the said isocyanate compound and polyol were made to react suitably are illustrated.

(Other contents)
In order to promote the penetration of the fireproofing agent into the woody material, the woody molded body of this embodiment can further contain a penetration aid. Here, examples of the penetration aid include succinic acid surfactants. Moreover, the number of parts of the penetration aid contained in the woody molded product of the present embodiment is 0.1 parts by mass or more from the viewpoint of enhancing the penetration of the fireproofing agent and reducing the change over time of the fireproofing agent to increase the stability. 0 parts by mass or less is preferable, and 0.1 parts by mass or more and 1.0 parts by mass or less is more preferable.

  The woody molded body of the present embodiment can further contain a water repellent in order to improve waterproofness. Here, examples of the water repellent include wax emulsion and dimethyl silicone water repellent. Further, the number of parts of the water repellent contained in the woody molded product of the present embodiment is preferably 0.1 parts by mass or more and 2.0 parts by mass or less, from the viewpoint of enhancing waterproofness and fireproofing, and 0.1 parts by mass. More preferred is at least 1.0 part by weight.

(Density of wood-based moldings)
From the viewpoint of increasing the strength of the molded body, the density of the wood-based molded body of this embodiment is 40 kg / m ³ or more, and preferably 150 kg / m ³ or more. Moreover, 50 kg / m < ³ > or more is preferable from a viewpoint of improving versatility.

[Embodiment 2]
In another embodiment of the present invention, a method for producing a wood-based molded body comprises 60 masses of at least one wood-based material selected from the group consisting of wood fibers, cellulose fibers, wood chips, wood particles, wood pieces, wheat straw and rice straw. A woody system in which 5 parts by weight or more and 35 parts by weight or less of a fireproofing chemical solution containing ammonium sulfate, borate and condensed ammonium phosphate is added to a part of 90 parts by weight or more and 90 parts by weight or less, and a fireproofing chemical solution is further added. A fireproofing process for drying the material, a woody material that has been fireproofed, and a mixing process for mixing at least one of 5 to 15 parts by weight of a fibrous adhesive and a liquid adhesive to obtain a density of 40 kg / m ³ or more wooden moldings by heat and pressure molding the resulting mixture into a mat integrated further shaped board by mixing And shape the process, including. Here, the production of the fireproofing chemical solution is a first sub-step in which ammonium sulfate is dissolved in water to obtain an aqueous ammonium sulfate solution, and an aqueous solution of ammonium sulfate-borate by dissolving borate in the aqueous ammonium sulfate solution at a concentration higher than the solubility in water. And a third sub-step in which condensed ammonium phosphate is dissolved in an ammonium sulfate-borate aqueous solution to obtain an ammonium sulfate-borate-condensed ammonium phosphate aqueous solution.

  According to such a method for producing a wood-based molded article, a fire-resistant chemical solution containing a high concentration of a fire-retardant agent is prepared, and a wood-based material treated with such a high-concentration fire-resistant chemical solution is molded, whereby A high woody molded body can be obtained.

(Fire prevention process)
In the production method of the wood-based molded product of this embodiment, first, at least 60 parts by weight of at least one wood-based material selected from the group consisting of wood fiber, cellulose fiber, wood chip, wood particle, wood piece, wheat straw and rice straw is 90 or more. A wood-based material to which 5 parts by mass or more and 35 parts by mass or less of a fireproofing agent solution containing ammonium sulfate, borate and condensed ammonium phosphate is added in a solid content of the fireproofing agent, and further the fireproofing agent solution is added. Including a fireproofing process for drying

(Manufacture of fire protection chemical solutions)
In the fireproofing process, the production of the fireproofing chemical solution used for the fireproofing of the wood-based material, first, in the first sub-process, ammonium sulfate is dissolved in water to obtain an ammonium sulfate aqueous solution. The present inventors have found that ammonium sulfate is a fireproofing agent, and is a dissolution aid that promotes the dissolution of borate in an aqueous solution and increases the dissolution stability of condensed ammonium phosphate in an aqueous solution. Is. The concentration of ammonium sulfate dissolved in water is not particularly limited, but is preferably 20% by mass or more and 50% by mass or less, and preferably 20% by mass or more and 30% by mass from the viewpoint of promoting the dissolution of borate and condensed ammonium phosphate in an aqueous solution. The mass% or less is more preferable.

  Next, in the second sub-step, the borate is dissolved in the ammonium sulfate aqueous solution at a concentration higher than the solubility in water to obtain an ammonium sulfate-borate aqueous solution. The dissolution of borate is promoted by ammonium sulfate, and an aqueous solution of ammonium sulfate-borate in which the borate is dissolved at a concentration higher than the solubility in water is obtained. Here, when the borate is sodium borate, the solubility of sodium tetraborate in 100 g of water at 20 ° C. is about 5 g, and the solubility of sodium octaborate in 100 g of water at 20 ° C. is about 10 g. .

  Next, in the third sub-process, condensed ammonium phosphate is dissolved in an ammonium sulfate-borate aqueous solution to obtain an ammonium sulfate-borate-condensed ammonium phosphate aqueous solution. Ammonium sulfate increases the dissolution stability of condensed ammonium phosphate and makes it difficult to precipitate condensed ammonium phosphate.

  Moreover, you may dissolve | melt the water-repellent agents, such as penetration assistants, such as a succinic-acid type surfactant, and / or a wax emulsion, and a dimethyl silicone water repellent, in said fireproofing agent solution.

  According to the above sub-process, 40 mass% or more of condensed ammonium phosphate can be dissolved at room temperature (for example, 25 ° C.), and 20 mass% or more of borate can be dissolved. A high concentration fireproofing chemical solution having a concentration of 40% by mass or more of salt and ammonium sulfate is obtained.

  Although there is no particular limitation on the method of adding the fire-retardant chemical solution obtained as described above to the wood-based material in an amount of 5 to 35 parts by weight, the viewpoint of uniformly adding the whole wood-based material Therefore, a method of mixing the wood-based material while spraying or applying the fire-proofing agent solution to the wood-based material or spraying or applying it is preferable.

  The method for drying the wood-based material to which the fire-retardant chemical solution has been added as described above is not particularly limited, but from the viewpoint of uniformly drying the wood-based material, hot air is applied to the wood-based material to which the fire-resistant chemical solution has been added. A method of stirring and mixing the wood-based material while feeding them is preferred.

(Mixing process)
In the manufacturing method of the wood-based molded body of this embodiment, the wood-based material subjected to the above fireproofing treatment is mixed with 5 to 15 parts by mass of fibrous adhesive and liquid adhesive. Including a mixing step. The method of mixing the fire-resistant wood-based material and at least one of the fibrous adhesive and the liquid adhesive is not particularly limited, but from the viewpoint of uniform mixing, a method of mixing with a carding machine A method of mixing by aeration is preferred.

(Molding process)
In the method for producing a wood-based molded body of the present embodiment, the mixture obtained by the above mixing is then accumulated in a mat shape, and further heated and pressed into a board shape, whereby the density is 40 kg / m ³ or more. A molding step of obtaining a woody molded article.

The method for accumulating the mixture in a mat shape is not particularly limited, but an air laid forming method or the like is preferable from the viewpoint of improving the uniformity of the material thickness and bulk density. The method for heat-press molding into a board shape is not particularly limited, but from the viewpoint of efficiently obtaining a uniform molded body, a method of continuous heat-pressing with a double conveyor belt, endless roll press or the like is preferable. The heating temperature may be a temperature at which the fire-resistant wood-based material in the mixture is bonded by an adhesive. Specifically, a fibrous adhesive having a melting point of 90 ° C. or more and 160 ° C. or less and having adhesiveness in at least one of the melting point and a hot water atmosphere of 80 ° C. or more and 100 ° C. or less is used. In such a case, it is sufficient that the temperature is 90 ° C. or higher and 160 ° C. or lower or the melting point or higher or the temperature is 80 ° C. or higher and 100 ° C. or lower. Moreover, when using the liquid adhesive which is a thermosetting compound or resin, it is sufficient to set it as the temperature more than the thermosetting temperature. The pressurizing pressure is a pressure at which the density of the wood-based molded body is 40 kg / m ³ or more.

(Secondary molding process)
The method for producing a wood-based molded body of the present embodiment further includes obtaining a wood-based molded body having a density of 150 kg / m ³ or more by further heat-pressing the wood-based molded body obtained in the molding step. A further forming step may be further included.

The heat and pressure molding in the secondary molding step is preferably performed in a humidified state from the viewpoint of facilitating molding. Moreover, sufficient pressure is required to increase the density of the wood-based molded body to 150 kg / m ³ or more.

(Manufacture of wood-based molded body having a laminated structure)
Using a plurality of wood-based materials of different types or sizes, a wood-based molded body having a laminated structure can be produced by the following steps.

  For example, before the above fire prevention treatment step, a classification step for dividing a wood particle into a surface layer particle particle having a maximum diameter of 130 μm or less and an inner layer particle particle having a maximum diameter greater than 130 μm, and a surface layer particle particle and an inner layer layer The above fire-resistant chemical solution is added to each of the particles, and the fire-resistant treatment step of drying the surface-layer wood particles and the inner-layer wood particles to which the fire-resistant chemical solution is further added, and the fire-treated surface-layer wood particles, fire-treated A wood system having a three-layer structure by laminating the inner layer wood particles and the fire-treated surface layer wood particles in this order and accumulating them in a three-layer mat shape, and further heating and pressing into a board shape A molded body is obtained.

(Synthesis of condensed ammonium phosphate)
In the following examples, condensed ammonium phosphate used as one of fireproofing agents was synthesized as follows. A mixture of 52 g of 85 mass% phosphoric acid and 90 g of urea (molar ratio phosphoric acid: urea = 1: 4) was heated from room temperature (25 ° C.) to 130 ° C. over 10 minutes and condensed at 130 ° C. for 30 minutes. The mixture was then cooled to obtain 130 g of condensed ammonium phosphate solid at room temperature (25 ° C.). The obtained condensed ammonium phosphate had 12% by mass of total phosphorus, 0.5% by mass of unreacted phosphorus, and the pH of the aqueous solution was 7.0 or more and 8.0 or less.

(Preparation of fire protection chemical solution A)
In the following examples, a fire prevention chemical solution A, which is one of the fire prevention chemical solutions used for the fire prevention treatment of the wood-based material, was prepared as follows. 200 g of sodium octaborate, 400 g of condensed sodium phosphate, and 1 g of a succinic acid surfactant (penetration aid) are added to an aqueous solution in which 200 g of white powder of ammonium sulfate is dissolved in 1 liter of water at room temperature (25 ° C.). Dissolve sequentially, fire-protecting agent 44.4% by weight (of which ammonium sulfate is 11.1% by weight, sodium octaborate is 11.1% by weight and condensed ammonium phosphate is 22.2% by weight) Solution A was obtained.

(Preparation of fire protection chemical solution B)
In the following examples, a fireproof chemical solution B, which is one of the fireproof chemical solutions used for the fireproofing treatment of wood-based materials, was prepared as follows. 100 g of boric acid and 50 g of sodium hydrogen carbonate are mixed and dissolved at room temperature in an aqueous solution in which 200 g of white powder of ammonium sulfate is dissolved in 1 liter of water at room temperature (25 ° C.), and then 100 g of sodium octaborate is dissolved. 400 g of ammonium acid and then 1 g of a succinic acid surfactant (penetration aid) are dissolved, and 44.4% by mass of the fireproofing agent (of which 11.1% by mass of ammonium sulfate and 11.1% by mass of borate) % And 22.2% by mass of condensed ammonium phosphate).

(Preparation of fire protection chemical solution C)
In the following examples, a fire prevention chemical solution C, which is one of the fire prevention chemical solutions used for the fire prevention treatment of the wood-based material, was prepared as follows. 200 g of sodium octaborate, 800 g of condensed ammonium phosphate, and 1 g of a succinic acid surfactant (penetration aid) are added to an aqueous solution in which 200 g of white powder of ammonium sulfate is dissolved in 1 liter of water at room temperature (25 ° C.). By sequentially dissolving, a fireproofing agent solution C containing 54.5% by weight of the fireproofing agent was obtained.

Example 1
The wood chips of conifers dried using a digester are cooked for 7 minutes at a steaming pressure of 6 kgf / cm ² and then sprayed with a fireproofing chemical solution A onto the wet wood fibers that have been defibrated using a defibrator at a plate spacing of 1 mm. Then, it was dried continuously with hot air at 150 ° C. to 170 ° C. for 2 minutes using a tube dryer to obtain a wood fiber obtained by treating 100 parts by weight of the wood fiber with 15 parts by weight of a fireproofing agent. Next, 92 parts by mass of fire-treated wood fibers, and 8 parts by mass of PET-PE fibers having a core-sheath structure in which the core part having a fineness of 5 dtex and the fiber length of 15 mm is carded and the core part is PET and the sheath part is PE The mixture was mixed using an airlaid forming machine. Next, the above mixture is accumulated in a mat shape using a lower suction type forming machine, and then continuously heated and pressed at 130 ° C. to 150 ° C. for 5 minutes using a double conveyor belt to obtain a thick wood-based molded body. A heat insulating board having a thickness of 50 mm and a density of 40 kg / m ³ was obtained. The physical properties of the obtained heat insulating board (woody molded body) were as follows. The thermal conductivity was 0.038 W / mK as measured by the heat flow meter method (HFM method) of JIS A1412-2. The total calorific value by the cone calorimeter method (CCM method) of ISO-5660 is 6.5 MJ / m ² (5-minute value), the maximum heat release rate is 42 kW / m ² (flame retardant grade 3 pass), and combustion The shape retention was about 84%. That is, it contracted by about 16%.

(Example 2)
After the wood chips of conifers dried using a digester are cooked for 7 minutes at a steaming pressure of 6 kgf / cm ² , the fireproof chemical solution C is sprayed onto the wet wood fibers that have been defibrated using a defibrator at a plate spacing of 1 mm. Then, it was dried continuously with hot air at 150 ° C. to 170 ° C. for 2 minutes using a tube dryer, to obtain a wood fiber obtained by treating 100 parts by weight of wood fiber with 34 parts by weight of a fireproofing agent. Next, 92 parts by mass of fire-treated wood fibers, and 8 parts by mass of PET-PE fibers having a core-sheath structure in which the core part having a fineness of 5 dtex and the fiber length of 15 mm is carded and the core part is PET and the sheath part is PE The mixture was mixed using an airlaid forming machine. Next, the above mixture is accumulated in a mat shape using a lower suction type forming machine, and then continuously heated and pressed at 130 ° C. to 150 ° C. for 5 minutes using a double conveyor belt to obtain a thick wood-based molded body. A heat insulating board having a thickness of 50 mm and a density of 40 kg / m ³ was obtained. The physical properties of the obtained heat insulation board (woody molded body) are as follows: thermal conductivity is 0.039 W / mK, total calorific value by CCM method is 5.5 MJ / m ² (10 minutes value), maximum heat generation The speed was 22 kW / m ² (flame retardant grade 2 pass), and the combustion shape retention was about 92%. That is, it contracted by about 8%.

(Example 3)
The wood chips of conifers that have been dried using a digester are cooked for 7 minutes at a steaming pressure of 6 kgf / cm ² , and then fire-resistant chemical solution B is sprayed onto the wet wood fibers that have been defibrated using a defibrator at a plate spacing of 1 mm. Then, it was dried continuously with hot air at 150 ° C. to 170 ° C. for 2 minutes using a tube dryer to obtain a wood fiber obtained by treating 100 parts by weight of wood fiber with 14 parts by weight of a fireproofing agent. Next, 90 parts by weight of fire-treated wood fibers and cardboard-treated fineness of 10 dtex and the sea part with a fiber length of 20 mm are PVA (JF-10 manufactured by Nihon Acetate / Poval) and the islands are biodegradable PP. 10 parts by mass of PVA-biodegradable PP fibers having a mass ratio of 2: 3 (PP containing 10% by mass of P-Life (R) manufactured by P-Life Japan Co., Ltd.) and an air-laid forming machine And mixed. Next, after the above mixture is accumulated in a mat shape using a lower suction type forming machine, it is continuously heated and pressed at 160 ° C. for 5 minutes using a double conveyor belt, so that the thickness is 100 mm and the density is 40 kg / m. Obtained ³ insulation boards. Next, the surface of the obtained heat insulation board is humidified by spraying with 500 g / m ^{2 of} water, and further subjected to secondary molding with a heating press at 120 ° C. for 5 minutes to obtain a wood-based molded body having a thickness of 25 mm and a density. A 158 kg / m ³ secondary molded insulation board was obtained. The physical properties of the obtained secondary molded heat insulating board (woody molded body) are a thermal conductivity of 0.043 W / mK and a total calorific value by the CCM method of 6.1 MJ / m ² (5 minutes value). The maximum heat generation rate was 35 kW / m ² (flame retardant grade 3 pass), and the combustion shape retention was about 75%. That is, it contracted by about 25%.

Example 4
The wood chips of conifers dried using a digester are cooked for 7 minutes at a steaming pressure of 6 kgf / cm ² and then sprayed with a fireproofing chemical solution A onto the wet wood fibers that have been defibrated using a defibrator at a plate spacing of 1 mm. Then, it was dried continuously with hot air at 150 ° C. to 170 ° C. for 2 minutes using a tube dryer to obtain a wood fiber obtained by treating 100 parts by weight of wood fiber with 18 parts by weight of a fireproofing agent. Next, 10 parts by mass of polyisocyanate binder (mixed with 90 parts by mass of MDI having an NCO content of 30% by mass and 10 parts by mass of 40% by mass of wax emulsion) is added to 100 parts by mass of wood fiber subjected to fire prevention treatment. And mixed using an air-laid forming machine. Next, the wood chips mixed with the polyisocyanate binder after being fire-treated are accumulated in a mat shape using a lower suction type forming machine, and then continuously for 5 minutes at 180 ° C. and 30 kgf / cm ² using a double conveyor belt. By heat press molding, a heat insulating board having a thickness of 8 mm and a density of 390 kg / m ³ was obtained as a wood-based molded body. The physical properties of the obtained heat insulation board (woody molded body) are as follows: thermal conductivity is 0.043 W / mK, total calorific value by CCM method is 6.3 MJ / m ² (5 minutes value), maximum heat generation The speed was 35 kW / m ² (flame retardant grade 3 pass), and the combustion shape retention was about 82%. That is, it contracted only about 18%. The bending strength was 15 N / mm ² when measured based on JIS A5908.

(Example 5)
The recycled fired paper treated with refiner is sprayed with fireproofing chemical solution A and dried continuously with hot air of 150 ° C. to 170 ° C. for 2 minutes using a tube dryer, and 100 parts by weight of wood fiber is 17 parts by weight of fireproofing chemical. Recycled recycled paper fiber treated with Next, 92 parts by mass of fire-treated wood fibers, and 8 parts by mass of PET-PE fibers having a core-sheath structure in which the core part having a fineness of 5 dtex and the fiber length of 15 mm is carded and the core part is PET and the sheath part is PE The mixture was mixed using an airlaid forming machine. Next, the above mixture is accumulated in a mat shape using a lower suction type forming machine, and then continuously heated and pressed at 130 ° C. to 150 ° C. for 5 minutes using a double conveyor belt to obtain a thick wood-based molded body. A heat insulating board having a thickness of 100 mm and a density of 55 kg / m ³ was obtained. The physical properties of the obtained heat insulation board (woody molded body) are as follows: thermal conductivity is 0.043 W / mK, total calorific value by CCM method is 7.5 MJ / m ² (5-minute value), maximum heat generation The speed was 41 kW / m ² (flame retardant third grade pass), and the combustion shape retention was about 81%. That is, it contracted by about 19%.

(Example 6)
The dried softwood wood chips were crushed and classified into a surface layer particle particle having a maximum diameter of 130 μm or less and an inner layer particle particle having a maximum diameter greater than 130 μm. Next, 14 parts by mass of the fireproofing chemical solution C was sprayed on 100 parts by weight of the wood particles for the surface layer, and dried with a drier. Further, 14 parts by mass of the fireproofing chemical solution C was sprayed on 100 parts by weight of the wood particles for the inner layer, and dried with a drier. Next, a melamine resin solution for PC (particle board) is 9 parts by weight and 40% by weight wax in 100 parts by weight of the fire-treated surface wood particles and 100 parts by weight of the fire-treated inner layer wood particles, respectively. 2 parts by mass of the emulsion was added and mixed using a blender and then dried with a dryer. Next, three layers of the above-described surface layer wood particle mixture, inner layer wood particle mixture and surface layer wood particle mixture have a set final density of 800 kg / m ³ , a set final thickness of each of the upper and lower surface layers of 3 mm and By stacking in a mat shape using a blender so that the final thickness of the inner layer is 9 mm, and then heat-press molding at 150 ° C. and a press pressure of 30 kgf / cm ² for 10 minutes using an endless roll press. A particle board having a total thickness of 15 mm and a density of 760 kg / m ³ was obtained as a wood-based molded body. Physical properties of the obtained particle board (woody molded body) are as follows: thermal conductivity is 0.13 W / mK, total calorific value by CCM method is 6.6 MJ / m ² (5-minute value), and maximum heat generation rate Was 46 kW / m ² (flame retardant grade 3 pass), and the combustion shape retention was about 75%. That is, it contracted by about 25%. The bending strength was 17 N / mm ² .

(Example 7)
The dried softwood wood chips were crushed and classified into a surface layer particle particle having a maximum diameter of 130 μm or less and an inner layer particle particle having a maximum diameter greater than 130 μm. Next, 43 parts by mass of the fireproofing chemical solution C was sprayed on 100 parts by weight of the wood particles for the surface layer, and dried with a drier. In addition, 25 parts by mass of the fireproofing chemical solution C was sprayed on 100 parts by weight of the inner layer wood particle and dried with a drier. Next, a polyisocyanate binder (90 parts by mass of MDI having an NCO content of 30% by mass, and 40% by mass of wax was added to 100 parts by mass of the fire-treated surface layer of wood particles and 100 parts by mass of the fire-treated inner layer wood particles. (Mixed with 10 parts by weight of emulsion) 12 parts by weight was added and mixed using a blender and dried with a dryer. Next, three layers of the above-described surface layer wood particle mixture, inner layer wood particle mixture and surface layer wood particle mixture have a set final density of 800 kg / m ³ , a set final thickness of each upper and lower surface layer of 3 mm, and an inner layer After collecting in a mat shape using a blender so that the set final thickness is 9 mm, using an endless roll press, it is heated and press-molded at 130 ° C. and a press pressure of 30 kgf / cm ² for 10 minutes, so that the wood system A particle board having a total layer thickness of 15 mm and a density of 790 kg / m ³ was obtained as a molded body. Physical properties of the obtained particle board (woody molded body) are as follows: the thermal conductivity is 0.13 W / mK, the total heat generation by the CCM method is 4.3 MJ / m ² (10 minutes value), and the maximum heat generation rate. Was 18 kW / m ² (flame retardant second grade pass), and the combustion shape retention was about 93%. That is, it contracted by about 7%. The bending strength was 18 N / mm ² .

(Example 8)
Using a blender, the fire-retardant chemical solution A was added to and mixed with straw of 30 mm or less processed softwood and dried with a dryer to obtain a straw that had 100 parts by weight of straw treated with 11 parts by weight of fire-retardant. . Next, 10 parts by mass of polyisocyanate binder (90 parts by mass of MDI having an NCO content of 30% by mass and 10 parts by mass of 40% by mass of wax emulsion) is added to 100 parts by mass of fire-treated straw. Mix using a blender. Next, this wheat straw mixture is made into a three-layer structure, the wheat straw in one layer and the wheat straw in the layer adjacent to the layer are laminated so as to be orthogonal to each other, and accumulated in a mat shape using a blender, and an endless roll An oriented strand board having a total thickness of 8 mm and a density of 400 kg / m ³ was obtained as a wood-based molded article by hot press molding at 190 ° C. and a press pressure of 30 kgf / cm ² for 10 minutes using a press. The physical properties of the obtained oriented strand board (woody molded body) are as follows: the thermal conductivity is 0.12 W / mK, and the total calorific value by the CCM method is 6.3 MJ / m ² (5-minute value). The maximum heat generation rate was 48 kW / m ² (flame retardant grade 3 pass), and the combustion shape retention was about 84%. That is, it contracted by about 16%. The bending strength was 25 N / mm ² .

  As described above, according to the present invention, the wood-based material is treated with the fire-resistant chemical solution having a high content of the fire-retardant chemical of 40% by mass or more, thereby adding and drying the fire-resistant chemical solution. It can be made efficient and a wood-based molded body having high fire resistance can be produced efficiently.

  Moreover, according to this invention, since it contains ammonium sulfate, a borate, and condensed ammonium phosphate as a fireproofing agent, in addition to excellent fireproofing property, the wood type molded object which has ant-proof property and humidity control property is obtained efficiently.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

Claims (2)

At least one wood-based material selected from the group consisting of wood fiber, cellulose fiber, wood chip, wood particle, piece of wood, wheat straw and rice straw is 60 parts by weight or more and 90 parts by weight or less, ammonium sulfate, borate and condensed ammonium phosphate A fire prevention treatment step of adding 5 parts by weight or more and 35 parts by weight or less of a fireproofing chemical solution containing the above, and further drying the wood-based material to which the fireproofing chemical solution is added,
A mixing step of mixing the wood-based material subjected to the fireproofing treatment and at least one adhesive of 5 to 15 parts by mass of a fibrous adhesive and a liquid adhesive;
A step of collecting the mixture obtained by the mixing into a mat shape and further forming a woody molded body having a density of 40 kg / m ³ or more by heating and pressing into a board shape,
The production of the fireproofing agent includes a first sub-step of dissolving ammonium sulfate in water to obtain an aqueous ammonium sulfate solution, and an aqueous solution of ammonium sulfate-borate by dissolving borate in the aqueous ammonium sulfate solution at a concentration higher than the solubility in water. A method for producing a wood-based molded article, comprising: a second sub-step; and a third sub-step in which condensed ammonium phosphate is dissolved in the ammonium sulfate-borate aqueous solution to obtain an ammonium sulfate-borate-condensed ammonium phosphate aqueous solution. . A method for producing a wood-based molded body, further comprising a secondary molding step for obtaining a wood-based molded body having a density of 150 kg / m ³ or more by further heat-pressing the wood-based molded body obtained in claim 1 . .