A flame-retardant biomass solid powder, its production method, and a flame-retardant board

Abstract

The present invention belongs to the technical field of new biomass materials. The present invention discloses a flame-retardant biomass solid powder, its production method, and a flame-retardant board. In the present invention, biomass is crushed into fine fibers and then impregnated with an aqueous solution containing an organic base and an acid, which improves the uniform distribution of the flame-retardant material therein. The flame-retardant material is uniformly distributed in the fine fiber structure. At the same time, the treated biomass can maintain a high bonding strength. The flame-retardant board obtained by thermoplastic treatment in a mold has a uniform flame-retardant effect inside and outside, and at the same time has a high strength, and its elastic modulus reaches 3800-4000 MPa, which is suitable for wide-range popularization and application.

Description

Technical Field

[0001] The present invention relates to the technical field of new biomass materials, and particularly relates to a flame-retardant biomass solid powder, a production method thereof, and a flame-retardant board. Background Art

[0002] Wooden boards and plywood are flammable materials without treatment. In the prior art, the raw materials of the boards are usually treated to achieve a flame-retardant effect. Limited by the original fiber solid dense structure of the raw materials, flame retardants are usually added to improve the flame-retardant effect. However, the flame retardants cannot penetrate evenly, so the flame retardancy of such materials is limited to the outer surface. In the case of contact with a high-temperature heat source, the flammable components inside can still volatilize and burn when heated, and the flame-retardant effect cannot be achieved. Therefore, the flame-retardant treatment requires high permeability of the flame retardant, which improves the requirements for the dosage and performance of the flame retardant, especially the use of liquid flame retardants is particularly important. In addition, the flame-retardant treatment process of wood will affect the flame-retardant performance of wood and also cause a decrease in the strength of wood. The existing methods for improving the flame-retardant performance of wood are as follows:

[0003] (1) Impregnation method. The impregnation method is a flame-retardant treatment method in which a liquid flame retardant is injected into wood under normal pressure, vacuum, pressure, or a combination of several pressures. The normal-pressure impregnation method is carried out under atmospheric pressure. This process is relatively simple, has low costs, and requires less equipment investment, but is only applicable to treating thin materials such as veneers or materials with good permeability. The pressure impregnation method is to place the wood in a high-pressure tank, first evacuate to remove the gas inside the wood, inhale the flame retardant under the action of a pressure difference, and then pressurize to press the flame retardant into the wood interior. (2) Spraying method. For wood that is not convenient for impregnation, the method of brushing or spraying a flame retardant can be used to isolate the heat source and prevent the wood from contacting air, thereby reducing the combustion performance of the wood. Such treatment cannot achieve a good flame-retardant effect when the product is exposed to high temperatures because the volatile components inside volatilize and are flammable. (3) Hot pressing method. The hot pressing method is to sprinkle a flame-retardant powder on the board or brush it on the wood board, and make it melt and penetrate into the wood board under hot pressing conditions. This method avoids the surface expansion of the wood board during pressure impregnation and drying after treatment. The disadvantage is that it is difficult to apply a sufficient dose. The problem of volatile flammable components in the above spraying method also exists. (4) Crushing the wood material, mixing it with a flame-retardant material, and then bonding it with glue to form plywood under pressure is a method to improve the flame-retardant performance. However, in order to achieve a certain structural strength, a large amount of adhesive needs to be used, and the flame-retardant performance of the adhesive directly affects the flame-retardant performance of the product. And the adhesive used is a liquid for bonding wood materials, and the bonding effect will also be affected by the flame retardant. Therefore, it is urgent in this field to develop a formed material with excellent flame retardancy and uniform distribution of flame retardancy everywhere. Summary of the Invention

[0004] The object of the present invention is to provide a flame-retardant biomass solid powder, its production method and a flame-retardant board, so as to solve the problems that the existing flame-retardant boards need to use adhesives, which affect the flame-retardant performance, and the flame-retardant materials are unevenly distributed in the boards, resulting in poor flame-retardant performance.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention provides a production method of a flame-retardant biomass solid powder, including the following steps:

[0007] a) Immerse the biomass in an aqueous solution containing an organic base and an acid, and then mix it with a mineral flame retardant to obtain a mixture;

[0008] b) React the mixture and then filter and separate it to obtain the flame-retardant biomass solid powder.

[0009] Preferably, in step a), the biomass is one or more of crop straws and their processing wastes, forest wastes, wood industry wastes, bamboo industry wastes, herbaceous plants and aquatic plants, and the length of the biomass is ≤ 30 mm.

[0010] Preferably, in step a), the mineral flame retardant is one or more of calcium sulfate, calcium bisulfate, magnesium sulfate, barium sulfate, calcium phosphate, calcium hydrogen phosphate, calcium dihydrogen phosphate, magnesium phosphate, magnesium hydrogen phosphate, metal bromides and metal chlorides; the metals in the metal bromides and metal chlorides are independently one or more of sodium, potassium, magnesium, calcium, strontium, barium, iron, zinc, aluminum, zirconium, gallium and tin; the mass of the mineral flame retardant is 5-30% of the mass of the mixture obtained by mixing the biomass and the mineral flame retardant.

[0011] Preferably, in step a), the organic base is one or more of imidazole compounds and their derivatives, pyridine compounds and their derivatives, pyrrole compounds and their derivatives, urea compounds and their derivatives, alkylamine compounds and their derivatives, triphenylphosphine and its derivatives, and trialkylphosphine and its derivatives.

[0012] Preferably, in step a), the acid is an organic acid and / or an inorganic acid. The organic acid is one or more of alkyl carboxylic acids and their derivatives, aromatic carboxylic acids and their derivatives, and amino acids and their derivatives. The inorganic acid is one or more of sulfuric acid, hydrochloric acid, bromic acid, iodic acid, nitric acid, trifluoroacetic acid, phosphoric acid, silicic acid, tungstic acid, molybdic acid, niobic acid, vanadic acid and heteropolyacids containing transition metals and their derivatives.

[0013] Preferably, in step a), the mass of the aqueous solution containing the organic base and the acid is 0.5 to 20 times the mass of the biomass. In the aqueous solution containing the organic base and the acid, the mass concentration of the organic base is 0.001 to 8%, and the mass concentration of the acid is 0.01 to 20%; the impregnation time is 10 to 14 h.

[0014] Preferably, in step b), the reaction temperature is ≥120 °C, the reaction time is 10 to 240 min, and the reaction pressure is 0.4 to 1 MPa.

[0015] The present invention also provides a flame-retardant biomass solid powder prepared by the production method of the flame-retardant biomass solid powder.

[0016] The present invention also provides a flame-retardant board, which is obtained by thermoplastic treatment of the flame-retardant biomass solid powder.

[0017] Preferably, the temperature of the thermoplastic treatment is 80 to 180 °C, and the time of the thermoplastic treatment is 10 to 360 min.

[0018] According to the above technical solutions, compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] The present invention crushes biomass into fine fibers, has a large contact area with the solid flame retardant powder, the solid flame retardant acts on the surface of the biomass particles treated by impregnation, dissolves and penetrates sufficiently, and the flame retardant is uniformly distributed in the fine granular fiber structure; the obtained solid powder is subjected to thermoplastic treatment in a molding die to obtain a flame-retardant board, and the obtained board has a uniform flame-retardant effect inside and outside. Specific Embodiments

[0020] The present invention provides a production method of a flame-retardant biomass solid powder, comprising the following steps:

[0021] a) Impregnating biomass in an aqueous solution containing an organic base and an acid, and then mixing with a mineral flame retardant to obtain a mixture;

[0022] b) Reacting the mixture, followed by filtration and separation to obtain a flame-retardant biomass solid powder.

[0023] In step a) of the present invention, the biomass is preferably one or more of crop straws and their processing wastes, forest wastes, wood industry wastes, bamboo industry wastes, herbaceous plants and aquatic plants, and more preferably one or more of crop straws and their processing wastes, forest wastes, wood industry wastes and bamboo industry wastes; the length of the biomass is preferably ≤30 mm, and more preferably 5 to 20 mm.

[0024] In step a) of the present invention, the mineral flame retardant is preferably one or more of calcium sulfate, calcium bisulfate, magnesium sulfate, barium sulfate, calcium phosphate, calcium hydrogen phosphate, calcium dihydrogen phosphate, magnesium phosphate, magnesium hydrogen phosphate, metal bromides and metal chlorides, and more preferably one or more of calcium sulfate, calcium bisulfate, magnesium sulfate, barium sulfate, calcium phosphate, calcium hydrogen phosphate and magnesium phosphate; the metal in the metal bromides and metal chlorides is preferably independently one or more of sodium, potassium, magnesium, calcium, strontium, barium, iron, zinc, aluminum, zirconium, gallium and tin, and more preferably one or more of potassium, magnesium, calcium, strontium, barium, iron, zinc and tin; the mass of the mineral flame retardant is preferably 5-30% of the mass of the mixture obtained by mixing the biomass and the mineral flame retardant, and more preferably 10-25% of the mass of the mixture obtained by mixing the biomass and the mineral flame retardant.

[0025] In step a) of the present invention, the organic base is preferably one or more of imidazole compounds and their derivatives, pyridine compounds and their derivatives, pyrrole compounds and their derivatives, urea compounds and their derivatives, alkylamine compounds and their derivatives, triphenylphosphine and its derivatives, trialkylphosphine and its derivatives, and more preferably one or more of imidazole compounds and their derivatives, pyrrole compounds and their derivatives, urea compounds and their derivatives, triphenylphosphine and its derivatives, and trialkylphosphine and its derivatives.

[0026] In step a) of the present invention, the acid is preferably an organic acid and / or an inorganic acid, and more preferably an organic acid and an inorganic acid; the organic acid is preferably one or more of alkyl carboxylic acids and their derivatives, aromatic carboxylic acids and their derivatives, and amino acids and their derivatives, and more preferably alkyl carboxylic acids and their derivatives and / or aromatic carboxylic acids and their derivatives; the inorganic acid is preferably one or more of sulfuric acid, hydrochloric acid, bromic acid, iodic acid, nitric acid, trifluoroacetic acid, phosphoric acid, silicic acid, tungstic acid, molybdic acid, niobic acid, vanadic acid and heteropolyacids containing transition metals and their derivatives, and more preferably one or more of sulfuric acid, hydrochloric acid, bromic acid, iodic acid, nitric acid, trifluoroacetic acid, phosphoric acid, silicic acid and vanadic acid.

[0027] In step a) of the present invention, the mass of the aqueous solution containing the organic base and the acid is preferably 0.5-20 times the mass of the biomass, and more preferably 2-15 times the mass of the biomass; in the aqueous solution containing the organic base and the acid, the mass concentration of the organic base is preferably 0.001-8%, and more preferably 0.005-5%, and the mass concentration of the acid is preferably 0.01-20%, and more preferably 0.05-15%; the impregnation time is preferably 10-14 h, and more preferably 11-13 h.

[0028] In step b) of the present invention, the temperature of the reaction is preferably ≥120 °C, more preferably 150 - 300 °C; the reaction time is preferably 10 - 240 min, more preferably 20 - 200 min; the reaction pressure is preferably 0.4 - 1 MPa, more preferably 0.5 - 0.9 MPa.

[0029] In step b) of the present invention, the reaction is a steam explosion reaction. Before the steam explosion reaction, the mixture is mixed with water, and the amount of water used is preferably 8 - 12 times that of the mixture, more preferably 9 - 10 times that of the mixture.

[0030] The present invention also provides a flame - retardant biomass solid powder prepared by the production method of the flame - retardant biomass solid powder.

[0031] The present invention also provides a flame - retardant board, which is obtained by thermoplastic treatment of the flame - retardant biomass solid powder.

[0032] In the present invention, the temperature of the thermoplastic treatment is preferably 80 - 180 °C, more preferably 100 - 160 °C; the thermoplastic treatment time is preferably 10 - 360 min, more preferably 20 - 350 min.

[0033] In the present invention, the thermoplastic treatment is carried out in a mold. The mold is a hollow mold with drain holes on the bottom surface; during the thermoplastic treatment, the solid powder is pressurized to drain water; the pressure of the pressurized water drainage is preferably 0.5 - 0.7 MPa, more preferably 0.6 MPa.

[0034] In the present invention, impregnation can soften and swell the raw material fibers. After the impregnation treatment, on the one hand, the prepared solid powder has high bonding strength, and on the other hand, the added flame - retardant material is well mixed with the treated biomass fibers, improving the dispersion of the flame - retardant material, so that the board obtained by integral thermoplastic molding has high flame - retardant performance.

[0035] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0036] Example 1

[0037] Crush corn straw into needle-shaped raw materials with a length below 30 mm. Take 100 g of the needle-shaped raw materials and soak them in 100 g of an aqueous solution containing triethylamine and hydrochloric acid for 12 h. The mass concentration of triethylamine is 1%, and the mass concentration of hydrochloric acid is 1%. Mix the soaked raw materials with 15 g of calcium hydrogen phosphate to obtain a mixture. Mix the mixture and water at a mass ratio of 1:10. In a steam explosion device, react at 170 °C and 0.5 MPa for 30 min, then quickly release the pressure to complete the steam explosion. Obtain solid plastic and flame-retardant powder through filtration. Fill the slurry powder into a 100 mm × 100 mm hollow mold with drainage holes at the bottom of the mold. Then, place a 100 mm × 100 mm stainless steel plate on top of the slurry in the mold, apply a hydraulic pressure of 0.6 MPa to squeeze out the water, heat through the outer sleeve of the stainless steel mold, raise the temperature to 150 °C, and maintain for 60 min. Then stop heating. When the temperature cools down to room temperature, take out the formed plate from the mold.

[0038] It is measured that the density of the plate obtained in this example is 1.1 g / cm 3 , and the elastic modulus is 3800 MPa. The plate obtained in this example does not burn in the flame for 10 s.

[0039] Example 2

[0040] Crush corn straw into needle-shaped raw materials with a length below 30 mm. Take 100 g of the needle-shaped raw materials and soak them in 100 g of an aqueous solution containing triethylamine and hydrochloric acid for 12 h. The mass concentration of triethylamine is 1%, and the mass concentration of hydrochloric acid is 1%. Mix the soaked raw materials with 15 g of magnesium hydrogen phosphate to obtain a mixture. Mix the mixture and water at a mass ratio of 1:10. In a steam explosion device, react at 170 °C and 0.6 MPa for 30 min, then quickly release the pressure to complete the steam explosion. Obtain solid plastic and flame-retardant powder through filtration. Fill the slurry powder into a 100 mm × 100 mm hollow mold with drainage holes at the bottom of the mold. Then, place a 100 mm × 100 mm stainless steel plate on top of the slurry in the mold, apply a hydraulic pressure of 0.6 MPa to squeeze out the water, heat through the outer sleeve of the stainless steel mold, raise the temperature to 150 °C, and maintain for 60 min. Then stop heating. When the temperature cools down to room temperature, take out the formed plate from the mold.

[0041] It is measured that the density of the plate obtained in this example is 1.1 g / cm 3 , and the elastic modulus is 4000 MPa. The plate obtained in this example does not burn in the flame for 10 s.

[0042] Comparative Example 1

[0043] Crush corn straw into needle-shaped raw materials with a length below 30 mm. Take 90 g of the needle-shaped raw materials and soak them in 100 g of an aqueous solution containing triethylamine and hydrochloric acid for 12 h. The mass concentration of triethylamine is 1%, and the mass concentration of hydrochloric acid is 1%. Mix the soaked raw materials with water at a mass ratio of 1:10 and react in a steam explosion device at 170 °C and 0.5 MPa for 30 min. Then quickly release the pressure to complete the steam explosion, and obtain plastic solid powder through filtration. Fill the slurry powder into a 100 mm × 100 mm hollow mold with drainage holes at the bottom of the mold. Then place a 100 mm × 100 mm stainless steel plate on top of the slurry in the mold, apply a hydraulic pressure of 0.6 MPa to squeeze out the water, and at the same time heat through the stainless steel mold jacket, raise the temperature to 150 °C, and maintain for 60 min, then stop heating. When the temperature cools down to room temperature, take out the formed plate from the mold.

[0044] It is measured that the density of the plate obtained in this comparative example is 1.1 g / cm 3 , and the elastic modulus is 3500 MPa; the plate obtained in this comparative example starts to burn within 2 seconds in the flame.

[0045] Comparative Example 2

[0046] Crush corn straw into needle-shaped raw materials with a length below 30 mm. Take 90 g of the needle-shaped raw materials and soak them in 100 g of an aqueous solution containing triethylamine and hydrochloric acid for 12 h. The mass concentration of triethylamine is 1%, and the mass concentration of hydrochloric acid is 1%. Mix the soaked raw materials with water at a mass ratio of 1:10 and react in a steam explosion device at 170 °C and 0.6 MPa for 30 min. Then quickly release the pressure to complete the steam explosion, and obtain plastic solid powder through filtration. Fill the slurry powder into a 100 mm × 100 mm hollow mold with drainage holes at the bottom of the mold. Then place a 100 mm × 100 mm stainless steel plate on top of the slurry in the mold, apply a hydraulic pressure of 0.6 MPa to squeeze out the water, and at the same time heat through the stainless steel mold jacket, raise the temperature to 150 °C, and maintain for 60 min, then stop heating. When the temperature cools down to room temperature, take out the formed plate from the mold.

[0047] It is measured that the density of the plate obtained in this comparative example is 1.1 g / cm 3 , and the elastic modulus is 3600 MPa. The plate obtained in this comparative example starts to burn within 2 seconds in the flame.

[0048] It can be seen from Examples 1-2 and Comparative Examples 1-2 that the flame-retardant plates obtained by the present invention not only have excellent flame-retardant properties, but also can achieve relatively high strength, and their elastic modulus reaches 3800-4000 MPa.

[0049] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A flame-retardant board prepared from a flame-retardant biomass solid powder, characterized in that, The preparation method of the flame-retardant board comprises the following steps: a) Immerse biomass in an aqueous solution containing organic base and inorganic acid, and then mix it with a mineral flame retardant to obtain a mixture; the aqueous solution containing organic base and inorganic acid refers to an aqueous solution containing triethylamine and hydrochloric acid; b) Mix the mixture with water for steam explosion reaction, and after the reaction, filter and separate to obtain flame-retardant biomass solid powder; the temperature of the steam explosion reaction is 150 - 300 °C, the reaction time is 10 - 240 min, and the reaction pressure is 0.4 - 1 MPa; c) Thermoplastically process the flame-retardant biomass solid powder, the temperature of the thermoplastic processing is 80 - 180 °C, and the time of the thermoplastic processing is 10 - 360 min; a flame-retardant board is obtained after the thermoplastic processing; wherein the mass of the mineral flame retardant is 5 - 30% of the mass of the mixture obtained by mixing biomass and the mineral flame retardant; in the aqueous solution containing organic base and inorganic acid, the mass concentration of the organic base is 0.001 - 8%, and the mass concentration of the inorganic acid is 0.01 - 20%.

2. The flame-retardant board prepared from the flame-retardant biomass solid powder according to claim 1, wherein In step a), the biomass is one or more of crop straws and their processing wastes, forest wastes, wood industry wastes, bamboo industry wastes, herbaceous plants and aquatic plants, and the length of the biomass is ≤ 30 mm.

3. The flame-retardant board prepared from the flame-retardant biomass solid powder according to claim 1, characterized in that In step a), the mineral flame retardant is one or more of calcium sulfate, calcium bisulfate, magnesium sulfate, barium sulfate, calcium phosphate, calcium hydrogen phosphate, calcium dihydrogen phosphate, magnesium phosphate, magnesium hydrogen phosphate, metal bromides and metal chlorides; the metals in the metal bromides and metal chlorides are independently one or more of sodium, potassium, magnesium, calcium, strontium, barium, iron, zinc, aluminum, zirconium, gallium and tin.

4. The flame-retardant board prepared from the flame-retardant biomass solid powder according to claim 1, wherein, In step a), the mass of the aqueous solution containing organic base and inorganic acid is 0.5 - 20 times the mass of the biomass; the impregnation time is 10 - 14 h.

5. The flame-retardant board prepared from the flame-retardant biomass solid powder according to claim 1, characterized in that, In step c), the thermoplastic processing is carried out in a mold, and the mold is a hollow mold with drainage holes at the bottom; during the thermoplastic processing, the solid powder is pressurized to drain water; the pressure of the pressurized drainage is 0.5 - 0.7 MPa.