Biodegradable plant fiber-based thermal insulation barrier plate

Abstract

The invention relates to a biodegradable plant fiber-based thermal insulation barrier plate which is composed of coarse plant fibers, treated fine plant fibers, starch, a reactive component A and a reactive component B. In the construction process, after all the components are prepared into slurry with a certain concentration, molding can be achieved by matching with subsequent heat treatment, and the barrier plate can be formed. The plate has good strength and toughness, has a closed porous structure to realize light weight, has a heat absorption material in reactive components, can realize good heat preservation and heat insulation effects, and can be used in the field of packaging containers or building and decorative plates.

Description

Technical Field

[0001] The invention relates to a board made of plant fibers, and in particular to a method for preparing a board having a closed-cell porous structure, good strength and toughness, and good heat absorption and heat preservation properties. Background Art

[0002] Plant fiber is a natural renewable resource that is widely found in agricultural and forestry resources and their processing waste. It is often not fully utilized and is abandoned in nature as garbage or destroyed by incineration, which on the one hand causes serious environmental pollution and on the other hand leads to a large amount of resource waste.

[0003] Plant fibers are used as industrial or civil materials, which require good formability during processing, and the molded materials have good strength and toughness. The fibers can be tightly combined through molding, but the compaction of the fibers during molding will also increase the density of the product, thus limiting its application. Lightweighting is still a problem that must be solved.

[0004] For the processing and molding of plant fiber as raw material, its performance is mainly determined by several aspects: first, the composition of the composite material, which will determine the basis of the material performance; second, the rheological processability of the raw material, which will determine the distribution and defects of the plant fiber in the molded body; third, the combination between the substances, which will determine the uniform energy dissipation of the material; fourth, in the lightweight process, the size and uniformity of the pores will also directly affect the mechanical properties. In the current research, high-strength plant fiber-based composite materials have relatively mature processes and products, but how to achieve the toughness of fully degradable plant fiber-based materials and ensure their lightweight and low density at the same time is still a difficult problem. At the same time, in remote areas, there is a large demand for boards, and it will be a good choice to process them into boards using local materials. Developing a simpler processing method to achieve rapid board formation will have better application value. Especially since there is no warming condition in rural areas, if the board can have a better warming effect, its application effect will be greatly improved.

[0005] To address this problem, this patent has developed a complete set of processing methods for plant fiber boards. Through plant fibers that can be directly processed, by mixing crude fibers and processed fibers, and by combining reactive components A and B that can be preserved for a long time, a simple molding process can be performed to obtain boards. The boards have excellent mechanical properties, are resistant to compression and bending, and have good heat absorption, heat preservation and insulation effects. They have good practicality and provide a better option for the development of fully degradable plant fiber products. Summary of the invention

[0006] The purpose of the present invention is to overcome the defects of plant fiber boards that cannot achieve high strength and toughness at low density and have poor thermal insulation, and to develop a plant fiber-based composite formula system and processing method to achieve high strength, low density and good thermal insulation and heat insulation effects.

[0007] The objective of the present invention is achieved through the following technical solutions: A biodegradable plant fiber-based thermal insulation barrier board, comprising the following components and corresponding mass proportions: Crude plant fiber 100 Processing fine plant fibers 15-40 Starch 6-12 Reactive component A 12-24 Reactive component B 12-32 Furthermore, the coarse plant fibers are obtained by crushing the plant fibers into a particle size of 400-1000 meshes and a length of 1-100 mm.

[0008] Furthermore, the treated fine plant fibers are pure fibers that have been treated by one or more physical, chemical, and biological methods to remove impurities and more than 90% of hemicellulose and lignin in the plant fibers, and have a particle size between 50-200 μm and an aspect ratio between 1:20.

[0009] Furthermore, the fine plant fibers may be treated by single or combined physical, chemical, biological methods such as acid-base treatment, steam explosion, and enzyme treatment.

[0010] Furthermore, the treated fine plant fibers can be prepared by the following process: the plant fibers are crushed into a particle size of 100-400 meshes, put into a cellulase aqueous solution with a mass concentration of 10-15%, slowly stirred at 30°C-40°C for 2-4 hours, heated to 80°C to inactivate the enzyme, then cooled and filtered, added into a steam explosion device, steam-exploded continuously for 3-5 times at a pressure of 3-5MPa and a temperature of 100-140°C, and then taken out and dried to obtain the product for use.

[0011] Furthermore, the reactive component A is a polyisocyanate solution dissolved in solvent oil, and the mass of the reactive component A is between 12-24% of the crude plant fiber; preferably, between 16-22%.

[0012] Furthermore, the solvent oil in the reactive component A is an oil having a boiling point between 110-150° C. and containing no hydroxyl groups, including but not limited to long-chain alkane and cycloalkane solvent oils; preferably, it is a long-chain alkane oil having a carbon number between 6 and 12, butanol, cyclohexanone, etc.

[0013] Furthermore, the polyisocyanate includes toluene diisocyanate (TDI), diphenylmethane-4,4'-diisocyanate (MDI), isophorone diisocyanate (IPDI), etc., and the mass fraction of isocyanate in the solution is between 15-35%.

[0014] Furthermore, the reactive component B is water-dispersible polyol, polyamine, glucose, and white carbon black powder, and the mass of the reactive component B is between 12-32% of the crude plant fiber, preferably, between 12-24%.

[0015] Furthermore, the proportions of the components in the reactive component B are as follows: the mass fraction of the polyol is between 6-12%; the mass fraction of the polyamine is between 2-4%; the mass fraction of glucose is between 1.2-3.6%; and the mass fraction of the white carbon black powder is between 0.6-1.2%.

[0016] Furthermore, the polyol of the reactive component B is a water-soluble polyol, including but not limited to pentaerythritol, trimethylolpropane, xylitol, sorbitol, and water-soluble small molecule polyether polyols and polyester polyols; the polyamine is a water-soluble polyamine, including but not limited to ethylenediamine, butanediamine, and hexamethylenetetramine.

[0017] Furthermore, the reactive component A and the reactive component B can be separately configured and sealed for storage, and can be taken out and used during processing.

[0018] Furthermore, the glucose is a polyhydroxy aldehyde having five hydroxyl groups, which can effectively participate in the reaction and strengthen the connection between substrates.

[0019] Furthermore, the starch is industrial starch or oxidized starch, which mainly plays a certain role as an adhesive in the system. Furthermore, the preparation process of the biodegradable plant fiber-based thermal insulation barrier board is as follows: (1) Add starch into water, heat to 50-60°C, stir evenly to form starch paste, then add coarse plant fiber and processed fine plant fiber, add a certain amount of water, stir evenly to form slurry for use; the mass fraction of starch in the slurry is between 10-20%; the mass fraction of coarse plant fiber is between 25-50%; the mass fraction of processed fine plant fiber is between 10-25%; (2) Before processing and molding, the slurry is put into the mold cavity, and then the reactive component A and the reactive component B are successively put into the mold cavity, the upper mold is lowered, heated to 80-110°C, pre-pressed at 3.2-6.4MPa for 2-4min, and then the mold is raised to release the pressure quickly; 0.5-1min after complete pressure relief, the upper mold plate is lowered again, heated to 140-180°C, and molded at 12.5-24.6MPa for 6-10min, and then the pressure is relieved at a speed of 3.5-6.5MPa / s to obtain a pre-product; (3) Place the pre-product in a 60-80°C environment for heat treatment for 30-60 minutes to obtain the final plate.

[0020] Furthermore, during the processing, the reactive component A and the reactive component B react with polyisocyanate and hydroxyl to achieve curing between the components, accompanied by a foaming and pore-forming process, thereby fixing the pore structure.

[0021] Furthermore, the addition of glucose in the reactive component B is beneficial to the connection between each component and the fiber and starch.

[0022] Furthermore, all components in the present invention, such as starch, plant fiber, glucose and the polyols and polyamines in the reactive component A, will react with the polyisocyanate in the reactive component B.

[0023] Furthermore, the subsequent heat treatment is mainly to further complete the reaction within the material, evaporate the internal solution, and solidify and improve the pore structure.

[0024] Furthermore, the coarse plant fiber is obtained by crushing the plant fiber into a particle size of 400-800 meshes and a length of 10-100 mm; Furthermore, the treated fine plant fibers are fibers that have been physically and chemically treated to remove more than 90% of hemicellulose and lignin, and have a particle size between 50 and 200 μm and an aspect ratio between 1:20.

[0025] Furthermore, the plant fiber is straw fiber, rice straw fiber, reed fiber, wood fiber, etc.

[0026] Furthermore, the particle size of the white carbon black powder is between 10-50 μm; the white carbon black powder is prepared by a gas phase method and has a certain heat absorption characteristic.

[0027] Furthermore, the barrier plate has a closed-cell porous structure with a pore size between 50 and 500 μm.

[0028] Furthermore, the molding material was prepared into standard specimens and the performance was tested according to the following standards: The pore structure of the material was measured by scanning electron microscope photographs of the material cross section; Material tensile properties: GB / T1040-1992 Test method for tensile properties of plastics; Material compression performance: GB / T1041-1992 Plastic compression performance test method; Material impact performance: GB / T1843-2008 Determination of plastic cantilever beam impact strength; Thermal conductivity of materials: GB / T 10295-2008 Thermal conductivity of thermal insulation materials / thermal conductivity thermal resistance test Material compression set: GB / T6669-2001 Determination of compression set of soft foam polymer materials The tested performance: The tensile strength is between 12-20MPa; The compression strength is between 2-4MPa; The elongation at break is between 100-300%; Impact strength is between 4.2-7.6kg / m 2 between; The compression set is between 0.30-0.80 / 30min and 1.95-3.85 / 24h; The thermal conductivity is between 0.16-0.12 W / (m·K).

[0029] Furthermore, the advantages of the present invention are: (1) The present invention adopts a curing and foaming integrated formula system, combined with process design to achieve stable bonding between plant fibers and foaming lightweight; (2) The main material and curing auxiliary material are separated, and the reactive components can be configured and stored separately, which is conducive to processing implementation; (3) The curing reaction system that has good compatibility with the main material is adopted to ensure the stable combination of the materials through reaction, thereby achieving good mechanical properties; (4) Multiple distributed foaming methods are implemented during the processing process; during the pre-molding process, the temperature is raised to above the boiling point of water to perform pre-foaming with steam; then, during the secondary heating and molding process, the oil in the system is evaporated, which not only exposes the polyisocyanate during the flow process to promote its reaction with other components in the matrix and combine the system substances, but also achieves secondary foaming due to the volatilization of the oil; in the later heat treatment, the reaction will be further improved to promote the formation of a closed-cell porous structure; (5) Effectively dispersed into silica powder, it has a certain endothermic effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a cross-sectional SEM image of the material prepared in Example 1; Figure 2This is a cross-sectional SEM image of the material prepared in Example 2. DETAILED DESCRIPTION

[0031] The exemplary implementation methods of the present invention will be described in detail below, but these implementation methods are for exemplary purposes only and the present invention is not limited thereto. Example 1

[0032] A biodegradable plant fiber-based thermal insulation barrier board, comprising the following components and corresponding mass proportions: Crude plant fiber 100 Processing of fine plant fibers22 Starch 6 Reactive component A 20 Reactive component B 14 The reactive component A is a polyisocyanate solution dissolved in solvent oil; the solvent oil is cyclohexanone, the polyisocyanate is isophorone diisocyanate (IPDI), and the mass fraction of IPDI in the solution is 25%.

[0033] The reactive component B is water-dispersible polyol, polyamine, glucose, and white carbon black powder, wherein the polyol is xylitol and the polyamine is diaminobutane; The mass fraction of xylitol is 8.5%; the mass fraction of diaminobutane is 3.2%; the mass fraction of glucose is 3.2%; and the mass fraction of white carbon black powder is 0.8%.

[0034] The crude plant fiber is made of rice straw fiber, which is crushed into 400-800 mesh particle sizes and has a length of 10-100 mm after removing impurities.

[0035] The preparation method of the treated fine plant fiber is as follows: using rice straw fiber as raw material, removing surface impurities and washing, then crushing the rice straw fiber into a particle size of 200-400 mesh, putting it into a 12% mass concentration of cellulase aqueous solution, slowly stirring at 35°C for 3h, heating to 80°C to inactivate the enzyme, then cooling and filtering, configuring it into an aqueous slurry with a mass concentration of 50%, putting it into a steam flash explosion equipment, steam flashing for 4 times at a pressure of 4.5MPa and a temperature of 110°C, then taking out and drying to obtain a product for standby use, and the obtained fiber has a particle size between 100-200μm and an aspect ratio between 1:20.

[0036] The particle size of the white carbon black powder is between 10-50 μm.

[0037] The starch is tapioca starch.

[0038] The preparation process of the biodegradable plant fiber-based thermal insulation barrier board is as follows: Add starch into water to form a suspension with a mass fraction of 18%, heat to 60°C, stir evenly to form starch paste, then add coarse plant fiber and processed fine plant fiber that meet the mass ratio, add a certain amount of water to make the mass fraction of starch reach 12%, stir evenly to form a slurry for use; (2) Before processing and molding, the slurry is put into the mold cavity, and then the reactive component A with 18% of the mass of crude plant fiber and the reactive component B with 26% of the mass of crude plant fiber are successively put into the mold cavity, the upper mold plate is lowered, heated to 90°C, pre-pressed at 4.2MPa for 2 minutes, and then the mold is opened to quickly release the pressure, and the pressure is completely released for 1 minute, and the upper mold is further lowered, heated to 170°C, and molded at 18.4MPa for 8 minutes, and then the pressure is released at a speed of 4.5MPa / s; the pre-product is obtained; (3) The pre-product is placed in a 70°C environment for heat treatment for 35 minutes to obtain the final plate.

[0039] The barrier plate has a porous structure, and its cross-sectional structure is as follows: Figure 1 The pore size is between 50-500μm, and the closed pores account for about 60% of all pores.

[0040] The properties of the prepared panels are shown in Table 1.

[0041] Example 2 A biodegradable plant fiber-based thermal insulation barrier board, comprising the following components and corresponding mass proportions: Crude plant fiber 100 Processing of fine plant fibers32 Starch 8.5 Reactive component A 16 Reactive component B 20 The reactive component A is a polyisocyanate solution dissolved in solvent oil; the solvent oil is butanol, the polyisocyanate is diphenylmethane-4,4'-diisocyanate (MDI), and the mass fraction of MDI in the solution is 25%.

[0042] The reactive component B is water-dispersible polyol, polyamine, glucose, and white carbon black powder, wherein the polyol is xylitol and the polyamine is hexamethylenetetramine; The mass fraction of xylitol is 10.2%; the mass fraction of hexamethylenetetramine is 2.6%; the mass fraction of glucose is 2.8%; and the mass fraction of white carbon black powder is 0.8%.

[0043] The crude plant fiber is made of reed fiber, which is crushed into 400-600 mesh particle sizes and has a length of 10-100 mm after removing impurities.

[0044] The preparation method of the treated fine plant fiber is as follows: using reed fiber as a raw material, after removing impurities, the reed fiber is crushed into a particle size of 200-400 meshes, and put into a weak alkaline NaOH aqueous solution with a mass concentration of 12%, and slowly stirred at 40°C for 5 hours, and then filtered out and cleaned with the alkali solution, and then put into a 9.5% by mass cellulase aqueous solution, and soaked at 30°C for 6 hours, and then quickly heated to 80°C to inactivate the enzyme, and then cooled and filtered, and finally taken out and dried to obtain a product for standby use. The particle size of the obtained fiber is between 100-200 μm, and the aspect ratio is between 1:20.

[0045] The particle size of the white carbon black powder is between 20-40 μm.

[0046] The starch is oxidized starch.

[0047] The preparation process of the biodegradable plant fiber-based thermal insulation barrier board is as follows: (1) Add starch into water to prepare a suspension with a mass fraction of 15%, heat to 60°C, stir evenly to form a starch paste, then add plant fiber and processed fine plant fiber that meet the mass ratio, add a certain amount of water to make the mass fraction of starch reach 12%, stir evenly to form a slurry for use; (2) Before processing and molding, the slurry is put into the mold cavity, and then the reactive component A and the reactive component B are successively put into the mold cavity, the upper mold plate is lowered, heated to 100°C, and pre-pressed at 8.4MPa for 2.5min, and then the mold is opened to quickly release the pressure. After 0.6min of complete pressure relief, the upper mold is further lowered, heated to 160°C, and molded at 15.2MPa for 6 minutes, and then the pressure is relieved at a speed of 5.5MPa / s to obtain a pre-product; (3) The pre-product is placed in a 65°C environment for heat treatment for 40 minutes to obtain the final plate.

[0048] The barrier plate has a porous structure, and its cross-sectional structure is as follows: Figure 2 The pore size is between 100-400μm, and the closed pores account for about 70% of all pores.

[0049] The properties of the prepared panels are shown in Table 1.

[0050] Example 3 A biodegradable plant fiber-based thermal insulation barrier board, comprising the following components and corresponding mass proportions: Crude plant fiber 100 Processing of fine plant fibers16 Starch 12 Reactive component A 18 Reactive component B 24 The reactive component A is a polyisocyanate solution dissolved in solvent oil; the solvent oil is n-decane with a boiling point of about 170° C., the polyisocyanate is toluene diisocyanate (TDI), and the mass fraction of TDI in the solution is 30%.

[0051] The reactive component B is water-dispersible polyol, polyamine, glucose, and white carbon black powder, wherein the polyol is a polyether polyol with a molecular weight of 4000, and the polyamine is ethylenediamine; the mass fraction of the polyether polyol is 8.5%; the mass fraction of butanediamine is 2.2%; the mass fraction of glucose is 3.6%; and the mass fraction of white carbon black powder is 1.0%.

[0052] The crude plant fiber is made from corn stalks, which are crushed into 400-800 mesh particles with a length of 10-100 mm after removing impurities.

[0053] The preparation method of the processed fine plant fiber is as follows: corn stalks are used as raw materials, and after removing impurities, the plant fibers are crushed into a particle size of 100-300 meshes, and are put into an alkaline aqueous solution of NaOH with a mass concentration of 10%, and slowly stirred at 45° C. for 6 hours, and the alkali solution is filtered out and cleaned, and water is added to prepare a slurry with a mass concentration of 65%, and the slurry is added into a steam flash explosion device, and steam flash explodes continuously for 4 times at a pressure of 4MPa and a temperature of 120° C., and then the material is taken out and dried to obtain a product for standby use. The particle size of the obtained fiber is between 50-150μm, and the aspect ratio is between 1:30.

[0054] The particle size of the white carbon black powder is between 10-50 μm.

[0055] The starch is corn starch.

[0056] The preparation process of the biodegradable plant fiber-based thermal insulation barrier board is as follows: (1) Add starch into water to prepare a suspension with a mass fraction of 16%, heat to 60°C, stir evenly to form a starch paste, then add coarse plant fiber and processed fine plant fiber in a certain mass ratio, add a certain amount of water so that the mass fraction of starch reaches 10%, stir evenly to form a slurry for use; (2) Before processing and molding, the slurry is put into the mold cavity, and then the reactive component A and the coarse reactive component B are successively put into the mold cavity, the upper mold plate is lowered, heated to 100°C, and pre-pressed at 5.5MPa for 3 minutes, and then the mold is opened to quickly release the pressure. After 0.5 minutes of complete pressure relief, the upper mold plate is further lowered, heated to 160°C, and molded at 20.6MPa for 9 minutes, and then the pressure is relieved at a speed of 4.1MPa / s to obtain a pre-product; (3) The pre-product is placed in a 75°C environment for heat treatment for 50 minutes to obtain the final plate.

[0057] The barrier plate has a porous structure with a pore size between 100-400 μm, wherein the closed pores account for about 80% of all pores.

[0058] The properties of the prepared panels are shown in Table 1.

[0059] Example 4 A biodegradable plant fiber-based thermal insulation barrier board, comprising the following components and corresponding mass proportions: Crude plant fiber 100 Processing of fine plant fibers36 Starch 8.5 Reactive component A 14 Reactive component B 30 The reactive component A is a polyisocyanate solution dissolved in solvent oil; the solvent oil is petroleum ether with a boiling point of about 120° C. and isophorone diisocyanate (IPDI), and the mass fraction of IPDI in the solution is 32%.

[0060] The reactive component B is water-dispersible polyol, polyamine, glucose, and white carbon black powder, wherein the polyol is pentaerythritol, the polyamine is hexamethylenetetramine, the mass fraction of pentaerythritol is 10.5%, the mass fraction of hexamethylenetetramine is 3.5%, the mass fraction of glucose is 2.5%, and the mass fraction of white carbon black powder is 1.2%.

[0061] The crude plant fiber is made of reed fiber, which is crushed into 300-600 mesh particle sizes and 5-100 mm in length after removing impurities.

[0062] The preparation method of the treated fine plant fiber is as follows: corn stalks are used as raw materials, and after removing impurities, the plant fibers are crushed into a particle size of 50-300 meshes, and are put into a weak alkaline NaOH aqueous solution with a mass concentration of 6%, and slowly stirred at 42° C. for 6 hours, and then the alkaline solution is filtered out and cleaned, and then put into a laccase aqueous solution with a mass fraction of 8.5%, and soaked at 30° C. for 8 hours, and then heated to 80° C. to inactivate the enzyme, and then cooled and filtered, and then the fibers are filtered out, and the product is dried for standby use, and the particle size is between 50-200 μm, and the aspect ratio is between 1:10.

[0063] The particle size of the white carbon black powder is between 10-50 μm.

[0064] The starch is tapioca starch.

[0065] The preparation process of the biodegradable plant fiber-based thermal insulation barrier board is as follows: (1) Add oxidized starch into water to prepare a suspension with a mass fraction of 15%, heat it to 60°C, stir it evenly to form a starch paste, then add coarse plant fiber and processed fine plant fiber that meet the mass ratio, add a certain amount of water so that the mass fraction of starch reaches 12%, stir it evenly to form a slurry for use; (2) Before processing and molding, the slurry is put into the mold cavity, and then the reactive component A and the reactive component B are successively put into the mold cavity, the upper mold plate is lowered, heated to 85°C, pre-pressed at 4.8MPa for 2.5min, and then the mold is opened to quickly release the pressure. After 1min of complete pressure relief, the upper mold is further lowered, heated to 140°C, and molded at 21.5MPa for 8min, and then the pressure is relieved at a speed of 3.8MPa / s to obtain a pre-product; (3) The pre-product is placed in a 70°C environment for heat treatment for 45 minutes to obtain the final plate.

[0066] The barrier plate has a porous structure with a pore size between 100-500 μm, wherein the closed pores account for about 70% of all pores.

[0067] The properties of the prepared panels are shown in Table 1.

[0068] Table 1. Properties of the prepared panels Performance parameters Example 1 Example 2 Example 3 Example 4 Cell diameter (μm) 50-500 100-400 100-400 100-500 Compression strength (MPa) 3.16 3.66 2.75 2.93 <![CDATA[Impact strength (kg / m 2 )]]> 5.82 6.71 5.37 6.22 Compression set 24h / 30min: 2.16% / 0.52% 24h / 30min: 3.13% / 0.64% 24h / 30min: 2.78% / 0.56% 24h / 30min: 3.14% / 0.62% Tensile strength (MPa) 17.7 19.4 14.8 17.6 Elongation at break (%) 214.6 161.3 249.5 186.7 Thermal conductivity (W / (m·K)) 0.14 0.12 0.14 0.15

Claims

1. A biodegradable plant fiber-based thermal insulation barrier board, consisting of the following components and their corresponding mass proportions: Crude plant fiber 100 Processing fine plant fibers 15-40 Starch 6-12 Reactive component A 12-24 Reactive component B 12-32 Features: The reactive component A is a polyisocyanate solution with solvent oil as solvent; The reactive component B is water-dispersible polyol, polyamine, glucose and white carbon black powder.

2. The biodegradable plant fiber-based thermal insulation barrier board according to claim 1, characterized in that: The solvent oil in the reactive component A is an oil having a boiling point between 110-150° C. and does not contain hydroxyl groups, including but not limited to long-chain alkane and cycloalkane solvent oils; the polyisocyanate includes toluene diisocyanate (TDI), diphenylmethane-4,4'-diisocyanate (MDI), isophorone diisocyanate (IPDI), etc., and the mass fraction of isocyanate in the solution is between 15-35%.

3. The biodegradable plant fiber-based thermal insulation barrier board according to claim 1, characterized in that: The proportions of the components in the reactive component B are as follows: the mass fraction of the polyol is between 6-12%; the mass fraction of the polyamine is between 2-4%; the mass fraction of glucose is between 1.2-3.6%; and the mass fraction of the white carbon black powder is between 0.6-1.2%.

4. The biodegradable plant fiber-based thermal insulation barrier board according to claim 1, characterized in that: The polyol of the reactive component B is a water-soluble polyol, including but not limited to pentaerythritol, trimethylolpropane, xylitol, sorbitol, and water-soluble small molecule polyether polyols and polyester polyols; the polyamine is a water-soluble polyamine, including but not limited to ethylenediamine, butanediamine, and hexamethylenetetramine.

5. The biodegradable plant fiber-based thermal insulation barrier board according to claim 1, characterized in that: The preparation process of the biodegradable plant fiber-based thermal insulation barrier board is as follows: (1) Add starch into water, heat to 50-60°C, stir evenly to form starch paste, then add coarse plant fiber and processed fine plant fiber, add a certain amount of water, stir evenly to form slurry for use; the mass fraction of starch in the slurry is between 10-20%; the mass fraction of coarse plant fiber is between 25-50%; the mass fraction of processed fine plant fiber is between 10-25%; (2) Before processing and molding, the slurry is put into the mold cavity, and then the reactive component A and the reactive component B are successively put into the mold cavity, the upper mold is lowered, heated to 80-110°C, pre-pressed at 3.2-6.4MPa for 2-4min, and then the mold is raised to release the pressure quickly; 0.5-1min after complete pressure relief, the upper mold plate is lowered again, heated to 140-180°C, and molded at 12.5-24.6MPa for 6-10min, and then the pressure is relieved at a speed of 3.5-6.5MPa / s to obtain a pre-product; (3) Place the pre-product in a 60-80°C environment for heat treatment for 30-60 minutes to obtain the final plate.

6. The biodegradable plant fiber-based thermal insulation barrier board according to claim 1, characterized in that: The coarse plant fibers are obtained by crushing the plant fibers into particles with a size of 400-1000 meshes and a length of 1-100 mm.

7. The biodegradable plant fiber-based thermal insulation barrier board according to claim 1, characterized in that: The treated fine plant fibers are fibers that have been physically and chemically treated to remove more than 90% of hemicellulose and lignin, and have a particle size between 50 and 200 μm and an aspect ratio between 1:

20.

8. The biodegradable plant fiber-based thermal insulation barrier board according to claim 1, characterized in that: The plant fiber is straw fiber, rice straw fiber, reed fiber, wood fiber and the like.

9. The biodegradable plant fiber-based thermal insulation barrier board according to claim 1, characterized in that: The particle size of the white carbon black powder is between 10-50 μm.

10. The biodegradable plant fiber-based thermal insulation barrier board according to claim 1, characterized in that: The pore size in the barrier plate is between 50-500 μm, and the proportion of closed pores is greater than 50%.

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