A wood charcoal layer crack repairing agent and repairing method

Abstract

The present invention discloses a wood charcoal layer crack repair agent and a repair method, and belongs to the field of wood processing technology. The wood charcoal layer crack repair agent of the present invention is composed of a combination of a polymerizable phosphorus-containing ionic liquid, an initiator, a cross-linking agent, a flame retardant enhancer, an antioxidant, deionized water, etc. The repair agent is applied to the wood or wood material through an impregnation or coating treatment process, and then the repair agent is pre-placed in the wood or wood material through a drying treatment process. When the wood is carbonized and shrinks at high temperature and cracks occur, the repair agent foams and expands under the high-temperature induction mechanism, blocks and repairs the cracks formed in the charcoal layer due to shrinkage and cracking, repairs the cracks, and improves the density and airtightness of the charcoal layer, thereby improving the quality of the charcoal layer, and further achieving the purpose of flame retardancy and fire prevention of wood and wood materials. The repair agent provided by the present invention enables the wood charcoal layer to have a self-repair mechanism of thermal induction effect, which solves the problem that traditional flame retardants cannot improve the quality of the wood charcoal layer and the cracks are irreversible.

Description

Technical Field

[0001] The invention relates to the technical field of wood processing, in particular to a wood char layer crack repairing agent and a repairing method. Background Art

[0002] Wood structures, as well as wood products used in homes and public spaces, are combustible materials, posing a potential fire hazard. With the widespread use of wood products in homes and public spaces, fire safety issues have become increasingly prominent. The use of flame-retardant wood materials is essential and a major concern for the industry.

[0003] Wood flame retardant and fire-resistant technology follows the principle of "dehydration carbonization" and continues to be used today. This promotes the carbonization of wood and relies on the barrier effect of the char layer to achieve flame retardancy and fire resistance. Therefore, the barrier effect of the char layer is a key factor. During wood combustion, hemicellulose, cellulose, and lignin decompose sequentially, producing combustible gases and a solid char layer. Although the char layer loses its mechanical properties, it retains the wood's microstructure. The porous char layer has a thermal conductivity of only one-third that of natural wood, hindering the transfer of heat and mass between the combustion surface and the wood's interior, thereby enhancing the wood's flame retardancy and fire resistance. Previous research on wood flame retardancy and fire resistance focused on increasing the amount of char formed during the carbonization process. However, the core of wood's flame retardancy and fire resistance lies in the loss of the protective function of the char layer. During the formation of the char layer, the physical and chemical structure is destroyed, resulting in shrinkage and cracking, also known as crazing. This deteriorates the integrity and airtightness of the char layer, rendering it ineffective as a barrier.

[0004] Existing flame-retardant and fire-resistant technologies have yet to address the problem of cracking in the char layer. This cracking, which loses its integrity and airtightness, impacts the material's flame-retardant properties. This cracking is irreversible; once formed, the wood itself and existing flame-retardant systems are unable to repair it. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention provides a wood charcoal crack repair agent and repair method. The present invention uses the repair agent to seal cracks formed by shrinkage of the charcoal layer, improving the airtightness of the charcoal layer and coating the surface of the substrate to achieve excellent flame retardant and fireproof properties.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] In one aspect, the present invention provides a wood charcoal layer crack repair agent, which is composed of the following components in parts by weight: 30-80 parts of a polymerizable short-chain alkyl imidazole phosphate ionic liquid, 0.1-3.5 parts of an initiator, 0.2-7.0 parts of a cross-linking agent, 10-30 parts of a PN flame retardant reinforcing agent, 2-20 parts of an antioxidant, and 30-60 parts of deionized water;

[0008] The polymerizable short-chain alkyl imidazole phosphate ionic liquid has the following structural formula:

[0009]

[0010] Furthermore, the polymerizable short-chain alkyl imidazole phosphate ionic liquid is prepared by the following method:

[0011] 1) Pass nitrogen gas into the reaction vessel equipped with a spherical condenser to exhaust the air;

[0012] 2) Add weighed trimethyl phosphate and 1-vinylimidazole into a container and stir to mix evenly.

[0013] 3) heating in an oil bath to 100-120°C and maintaining the temperature for 1-3 hours, then lowering the temperature of the product to below 70°C while maintaining a nitrogen atmosphere and continuously stirring to obtain a deep red liquid product;

[0014] 4) Slowly add ethyl acetate solution to the liquid product until the product becomes a light yellow solid, filter to obtain a light yellow filter residue; repeat the ethyl acetate solution washing 3-4 times.

[0015] 5) Transfer the light yellow residue to a rotary evaporator and distill under reduced pressure in a 60°C water bath;

[0016] 6) The dark red liquid product obtained after the reduced pressure distillation is placed in a vacuum drying oven and vacuum dried at 80° C. for 24-48 hours to obtain a polymerizable short-chain alkyl imidazole phosphate ionic liquid.

[0017] Preferably, the molar ratio of trimethyl phosphate to 1-vinylimidazole is 1:0.5-1.

[0018] Furthermore, the initiator is azobisisobutylamidine hydrochloride (AIBA); and the cross-linking agent is N,N-methylenebisacrylamide (MBA).

[0019] The PN flame retardant enhancer is one or more of phosphoric acid, ammonium polyphosphate, monoammonium phosphate, diammonium phosphate, melamine orthophosphate, melamine pyrophosphate, and phosphate ester oligomers. The antioxidant is one or more of butylated hydroxytoluene, talc, mica, kaolin, halloysite, montmorillonite, modified boron silicate, silica sol, SiO2, and a boron compound. These enhance the strength of the carbon layer, its resistance to high-temperature oxidation, and prevent it from being ruptured or detached by flames.

[0020] The preparation method of the wood charcoal layer crack repair agent is as follows: an initiator, a crosslinking agent, a PN flame retardant enhancer, an antioxidant, and deionized water are added to a polymerizable short-chain alkyl imidazole phosphate ionic liquid, and stirred evenly to prepare the wood charcoal layer crack repair agent.

[0021] In another aspect, the present invention provides a method for repairing cracks in the charcoal layer of wood, using the above-mentioned repair agent. Specifically, the method comprises:

[0022] Step 1: Decontamination of wood and wood materials;

[0023] Step 2: Apply the above-mentioned repair agent to the surface of the material described in step 1, or vacuum-immerse the material described in step 1 in the above-mentioned repair agent;

[0024] Step 3: Dry the material after step 2;

[0025] Step 4: The dried material is polymerized.

[0026] Furthermore, the method for repairing cracks in the wood charcoal layer comprises:

[0027] Step 1: Decontamination of wood and wood materials;

[0028] Step 2: Apply the prepared wood charcoal layer crack repair agent to the surface of the wood or wooden material, place it at room temperature for 6-10 hours, and then apply it again. Repeat this process 3-6 times. The liquid coating amount is 150-1000g / m 2 ;

[0029] Step 3: Place the treated material in a drying kiln, raise the temperature to 40-60°C, and dry for 6-12 hours;

[0030] Step 4: Raise the temperature to 70-120°C and maintain for 4-8 hours, then cool to room temperature to obtain modified wood and wood materials.

[0031] Furthermore, the method for repairing cracks in the wood charcoal layer comprises:

[0032] Step 1: Decontamination of wood and wood materials;

[0033] Step 2: After decontamination, place the wood and wood materials into a treatment tank, evacuate to 0.1MPa, and maintain for 30-120min; add the prepared wood charcoal layer crack repair agent into the tank so that the repair agent completely submerges the material; then adjust the pressure to 10-30MPa and maintain for 0.5-6h; then vacuum treat at 0.1MPa for 15-30min.

[0034] Step 3: Place the treated material in a drying kiln, raise the temperature to 40-60°C, and dry for 12-24 hours.

[0035] Step 4: Raise the temperature to 70-120° C. and maintain for 4-8 hours; cool to room temperature to obtain modified wood and wood materials.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1) The repair agent provided by the present invention significantly improves the cracking of the wood charcoal layer, forms a dense and airtight charcoal layer, improves the quality of the charcoal layer and the surface fire resistance of the wood or wood material, and makes the wood or wood material have good flame retardant properties.

[0038] 2) The present invention first uses the provided repair agent to treat the wood, then dries it, and finally heats it to polymerize the ionic liquid inside the wood, completing the treatment of the wood; during use, when a fire occurs, the temperature rises, resulting in the formation of a char layer in the wood. At the same time, the high temperature will also induce the polymerized ionic liquid to foam and expand, and the foaming and expansion process has a synchronous mechanism with the shrinkage and cracking of the char layer. Shrinkage and cracking during the carbonization process of wood are unavoidable and irreversible. The work of the repair agent should be synchronized with the shrinkage and cracking of the char layer. Advancing or delaying the work is not conducive to improving the quality of the char layer. The present invention successfully prepares a polymerized ionic liquid with an expansion temperature (180-250°C) that is compatible with the temperature of the fiber decomposition point of wood (180-250°C) through a specific ionic liquid preparation process, ensuring that the formation and cracking of the char layer and the foaming and expansion of the polymerized ionic liquid proceed synchronously. The cracked char layer gaps will be filled during the foaming process, thereby achieving the repair of the cracked char layer and improving the flame retardant properties of the wood.

[0039] 3) The repair agent provided by the present invention has good foaming and expansion properties and the expanded carbon layer is of excellent quality. Poor foaming and expansion properties and expanded carbon layer quality are not conducive to obtaining a good repair effect and also have a negative impact on flame retardancy and fire resistance.

[0040] 4) The repair agent provided by the present invention is pre-placed in wood or wood materials and has no adverse effect on the physical and mechanical properties of the material at room temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a picture of the surface morphology of the untreated fir sawn timber sample after burning;

[0042] Figure 2 This is a picture of the surface morphology of the wood treated in Example 1 of the present invention after burning;

[0043] Figure 3 This is a picture of the surface morphology of the wood treated in Example 2 of the present invention after burning;

[0044] Figure 4 This is a picture of the surface morphology of the wood treated in Example 3 of the present invention after burning;

[0045] Figure 5 This is a picture of the surface morphology of the wood treated in Example 4 of the present invention after burning;

[0046] Figure 6This is a picture of the surface morphology of the wood treated in Example 5 of the present invention after burning;

[0047] Figure 7 This is a picture of the surface morphology of the wood treated in Example 6 of the present invention after burning;

[0048] Figure 8 This is a picture of the surface morphology of the wood treated in Example 7 of the present invention after burning;

[0049] Figure 9 This is a picture of the surface morphology of the wood treated in Comparative Example 1 of the present invention after burning;

[0050] Figure 10 This is a picture of the surface morphology of the wood treated in Comparative Example 2 of the present invention after burning;

[0051] Figure 11 This is a picture of the surface morphology of the wood after burning treated in Comparative Example 3 of the present invention;

[0052] Figure 12 This is a picture of the surface morphology of the wood after burning treated in Comparative Example 4 of the present invention;

[0053] Figure 13 This is a picture of the surface morphology of the wood after burning after being treated in Comparative Example 5 of the present invention. DETAILED DESCRIPTION

[0054] In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0055] In the present invention, the materials and reagents used, unless otherwise specified, can be obtained from commercial sources. In the preparation of the repair agent, azobisisobutylamidine hydrochloride (AIBA) is selected as the initiator and N,N-methylenebisacrylamide (MBA) is selected as the cross-linking agent.

[0056] The present invention provides a wood charcoal layer crack repair agent and a repair method, and specific embodiments are as follows.

[0057] Example 1

[0058] A method for repairing cracks in a wood charcoal layer, comprising:

[0059] 1) Sand the surface of fir sawn timber (length * width * thickness 100 * 100 * 20 mm) and place it in a treatment tank;

[0060] 2) Evacuate the treatment tank to a vacuum degree of 0.1 MPa for 30 minutes. Suck the prepared wood charcoal crack repair agent into the tank by vacuum until the material is completely submerged in the repair agent. Then, apply pressure to 30 MPa for 0.5 hours. Finally, vacuum the tank again to a vacuum degree of 0.1 MPa for 15 minutes.

[0061] 3) Drying: Place the treated material in a drying kiln, raise the temperature to 60°C, and dry for 12 hours;

[0062] 4) Polymerization treatment: raise the temperature to 70° C. and maintain for 8 hours; cool to room temperature to obtain modified wood and wood materials.

[0063] In this embodiment, the wood charcoal layer crack repair agent is prepared by mixing the following components in parts by weight: 30 parts of polymerizable short-chain alkyl imidazole phosphate ionic liquid, 0.1 parts of initiator, 1 part of cross-linking agent, 10 parts of phosphoric acid, 5 parts of butylated hydroxytoluene, and 30 parts of deionized water.

[0064] Among them, the polymerizable short-chain alkyl imidazole phosphate ionic liquid can be prepared by the following method:

[0065] 1) Pass nitrogen gas into the reaction vessel equipped with a spherical condenser to exhaust the air.

[0066] 2) Add weighed trimethyl phosphate (1 mol) and 1-vinylimidazole (0.67 mol) into a container and stir for 10 minutes to mix them evenly.

[0067] 3) Heat in an oil bath to 100°C and maintain for 2 hours to terminate the reaction. Lower the temperature of the product to below 70°C while maintaining a nitrogen atmosphere and stirring continuously to obtain a deep red liquid product.

[0068] 4) Slowly add ethyl acetate solution to the liquid product until the product turns into a light yellow solid. Filter to obtain a light yellow filter residue. Repeat the ethyl acetate solution washing four times.

[0069] 5) The light yellow residue was transferred to a rotary evaporator and distilled under reduced pressure in a water bath at 60°C.

[0070] 6) The dark red liquid product obtained after vacuum distillation was placed in a vacuum drying oven and vacuum dried at 80° C. for 48 hours. After cooling to room temperature, a light yellow solid substance - a polymerizable short-chain alkyl imidazole phosphate ionic liquid - was obtained.

[0071] The prepared polymerizable short-chain alkyl imidazole phosphate ionic liquid is 1-vinyl-3-methyl-imidazole dimethyl phosphate, and its structure is shown below:

[0072]

[0073] Example 2

[0074] A method for repairing cracks in a wood charcoal layer, comprising:

[0075] 1) Decontaminate the surface of fir sawn timber (length * width * thickness 100 * 100 * 20 mm) by sanding;

[0076] 2) Apply the prepared wood charcoal layer crack repair agent on the surface of wood or wood materials, leave it at room temperature for 6 hours, apply it again, and repeat this 6 times; the liquid coating amount is 400g / m 2 ;

[0077] 3) Drying: Place the treated material in a drying kiln, raise the temperature to 40°C, and dry for 12 hours;

[0078] 4) Polymerization treatment: raise the temperature to 120° C. and maintain for 4 hours; cool to room temperature to obtain modified wood and wood materials.

[0079] In this embodiment, the wood charcoal layer crack repair agent is composed of the following components by weight: 80 parts of polymerizable short-chain alkyl imidazole phosphate ionic liquid, 3.5 parts of initiator, 0.2 parts of crosslinking agent, 10 parts of monoammonium phosphate, 5 parts of diammonium phosphate, 2 parts of kaolin, and 40 parts of deionized water.

[0080] The preparation method of the polymerizable short-chain alkyl imidazole phosphate ionic liquid is the same as that in Example 1.

[0081] Example 3

[0082] A method for repairing cracks in a wood charcoal layer, comprising:

[0083] 1) Use compressed air to clean the surface of fir sawn timber (length * width * thickness 100 * 100 * 20 mm) and then place it in a treatment tank;

[0084] 2) Vacuum treatment: After decontamination, place the wood and wood materials in a treatment tank and vacuum them to 0.1 MPa for 120 minutes. Then, suck the prepared wood char crack repair agent into the tank through vacuum, so that the repair agent completely covers the material. Pressurize the tank to 10 MPa for 6 hours, and then vacuum the tank again to 0.1 MPa for 30 minutes.

[0085] 3) Drying treatment: Place the treated material in a drying kiln, raise the temperature to 40°C, and dry for 24 hours.

[0086] 4) Polymerization treatment: raise the temperature to 100° C. and maintain for 6 hours; cool to room temperature to obtain modified wood and wood materials.

[0087] In this embodiment, the wood charcoal layer crack repair agent is composed of the following components by weight: 60 parts of polymerizable short-chain alkyl imidazole phosphate ionic liquid, 2 parts of initiator, 7.0 parts of cross-linking agent, 15 parts of pentaerythritol, 15 parts of dipentaerythritol, 20 parts of silica sol, and 60 parts of deionized water.

[0088] The preparation method of the polymerizable short-chain alkyl imidazole phosphate ionic liquid is the same as that in Example 1.

[0089] Example 4

[0090] A method for repairing cracks in a wood charcoal layer, comprising:

[0091] 1) Use compressed air to pressurize the surface of fir sawn timber (length * width * thickness is 100 * 100 * 20mm).

[0092] 2) Apply the prepared wood charcoal layer crack repair agent to the surface of wood or wooden materials, leave it at room temperature for 10 hours, and then apply it again. Repeat this process 5 times. Liquid coating amount 300g / m 2 .

[0093] 3) Drying treatment: Place the treated material in a drying kiln, raise the temperature to 50°C, and dry for 10 hours.

[0094] 4) raising the temperature to 120° C. and maintaining it for 4 hours; cooling it to room temperature to obtain modified wood and wood materials.

[0095] In this embodiment, the wood charcoal layer crack repair agent is composed of the following components by weight: 50 parts of polymerizable short-chain alkyl imidazole phosphate ionic liquid, 1 part of initiator, 4 parts of cross-linking agent, 10 parts of sucrose, 10 parts of starch, 5 parts of kaolin, 5 parts of halloysite, and 50 parts of deionized water.

[0096] The preparation method of the polymerizable short-chain alkyl imidazole phosphate ionic liquid is the same as that in Example 1.

[0097] Example 5

[0098] In this embodiment, the wood charcoal layer crack repair agent is composed of the following components by weight: 40 parts of polymerizable short-chain alkyl imidazole phosphate ionic liquid, 2 parts of initiator, 3 parts of cross-linking agent, 10 parts of melamine orthophosphate, 10 parts of melamine pyrophosphate, 8 parts of kaolin, and 50 parts of deionized water.

[0099] The remaining conditions are the same as those in Example 3.

[0100] Example 6

[0101] In this embodiment, the wood charcoal layer crack repair agent is composed of the following components by weight: 40 parts of polymerizable short-chain alkyl imidazole phosphate ionic liquid, 2 parts of initiator, 3 parts of cross-linking agent, 10 parts of melamine orthophosphate, 10 parts of melamine pyrophosphate, 8 parts of kaolin, and 50 parts of deionized water.

[0102] The remaining conditions are the same as those in Example 4.

[0103] Example 7

[0104] A method for repairing cracks in a wood charcoal layer, comprising:

[0105] 1) Use compressed air to clean the surface of fir sawn timber (length * width * thickness 100 * 100 * 20 mm) and place it in the treatment tank

[0106] 2) Apply the prepared wood charcoal layer crack repair agent to the surface of the wood or wooden material, leave it at room temperature for 10 hours, and then apply it again. Repeat this process 5 times. Liquid coating amount 320g / m 2 .

[0107] 3) Drying: Place the treated material in a drying kiln, raise the temperature to 50°C, and dry for 10 hours.

[0108] 4) raising the temperature to 120° C. and maintaining it for 4 hours; cooling it to room temperature to obtain modified wood and wood materials.

[0109] The formula of the wood charcoal layer crack repair agent in this embodiment is the same as the repair agent formula in Example 3.

[0110] In order to further illustrate the beneficial effects of the present invention, the following comparative examples are constructed.

[0111] Comparative Example 1

[0112] In this comparative example, 1-vinylimidazole was replaced by an equal amount of 2-methylimidazole, and the other conditions were the same as those in Example 6.

[0113] Comparative Example 2

[0114] In this comparative example, 1-vinylimidazole was replaced by an equal amount of 1-phenylimidazole, and the other conditions were the same as those in Example 6.

[0115] Comparative Example 3

[0116] In this comparative example, 1-vinylimidazole was replaced by an equal amount of 3-hexylimidazole, and the other conditions were the same as those in Example 6.

[0117] Comparative Example 4

[0118] The ionic liquid in this comparative example was prepared as follows: 0.01 g of 2,6-di-tert-butyl-4-methylphenol (BHT) and 30 mL of n-hexane were added to 9.42 g of N-vinylimidazole, followed by the dropwise addition of 21.78 g of ethyl bromide. The mixture was stirred at 40°C under nitrogen for 24 hours, resulting in the formation of a precipitate. After completion of the reaction, the mixture was filtered, washed three times with 20 mL of n-hexane, and dried under vacuum at 40°C for 3 hours to obtain the product. All other conditions were the same as those in Example 6.

[0119] Comparative Example 5

[0120] In this comparative example, the coating amount of the wood charcoal layer crack repair agent liquid is 50g / m 2 The remaining conditions are the same as those in Example 6.

[0121] The properties of the modified wood prepared in Examples 1-7 and Comparative Examples 1-5 were tested, and untreated wood was used as a control, as shown below.

[0122] Flame retardant performance test method: Cone calorimeter (ISO 5660), radiation intensity 50kW / m 2 The sample size is 100mm×100mm×20mm, and each example and comparative example is tested three times. The relevant experimental process can be found in T / CNFPIA 3019-2022 "Flame Retardant Impregnated Film Paper Faced Plywood and Blockboard", and the flame retardant grade is determined according to Appendix A. PHRR 300s The peak heat release rate within 300s, THR 300s It is the total amount of heat released in 300s.

[0123] See Table 1-2 for specific test results.

[0124] Table 1 Cone calorimeter data of the embodiment

[0125]

[0126] As shown in Table 1, the repair agent of the present invention can significantly reduce the PHRR of wood. 300s and THR 300s , improve the flame retardant properties of wood; and by comparison of Example 2, Example 4 and Example 6-7 with the remaining examples, the PHRR of the surface coating process samples 300s and THR 300sLower than the impregnation process; and the combustion grade of wood treated by the surface coating process reaches B1B level. This may be because the coating process is to apply the repair agent directly on the surface of the wood, resulting in a higher content of the repair agent on the surface, which can timely modify the char layer formed on the surface of the wood and improve the flame retardant performance; while in the impregnation process, a large part of the repair agent enters the interior of the wood, and the repair agent on the surface of the wood only enters by impregnation. The content of the surface repair agent is relatively low, and the repair effect on the wood charcoal layer is not as good as the coating process, so its flame retardant performance may be slightly worse.

[0127] And by Figure 1-8 It can be seen that a carbon layer is formed on the surface of the original wood after high temperature, but the carbon layer is obviously cracked, with a large number of cracks, a deeper depth, and a wider gap; compared with the original wood, the wood treated by the impregnation process has significantly fewer surface cracks and smaller gaps; the wood treated by the surface coating process has almost no cracks on the surface, which proves that the repair agent of the present invention can significantly improve the flame retardant properties of wood and improve its flame retardant grade.

[0128] The two processes of the present invention can be selected according to the state of the wood to be treated. When the wood sample to be treated is already an existing product (such as floor, beam, column, etc.), the coating process can be selected, which is convenient and fast; when the wood is a log or has not been processed into a product, the impregnation process can be used. During the impregnation process, the repair agent enters the interior of the wood, while maintaining good flame retardant properties without affecting its subsequent processing.

[0129] Table 2 Comparative Example Cone Calorimeter Data

[0130]

[0131] As shown in Table 2, compared with Comparative Examples 1-3, the flame retardant properties of the polymerized ionic liquids of the present invention are superior to those of the non-polymerizable ionic liquids. When the alkyl chain of the ionic liquid increases (Comparative Example 3), the flame retardant properties decrease. Compared with Comparative Example 4, the flame retardant properties of the phosphate anion are significantly superior to those of the halogen anion. Compared with Comparative Example 5, the flame retardant properties are poorer when the coating amount is low.

[0132] In summary, the present invention successfully prepares a polymeric ionic liquid with an expansion temperature (180-250°C) that is compatible with the fiber decomposition point of wood (180-250°C) through a specific ionic liquid preparation process, ensuring that the cracking of the carbon layer and the foaming and expansion of the polymeric ionic liquid occur simultaneously. During the foaming process, the cracked carbon layer gaps are filled, the cracked carbon layer is repaired, and the flame retardant properties of the wood are improved.

[0133] The above is a preferred embodiment of the present invention. For ordinary technicians in this technical field, making several improvements and modifications without departing from the principles of the present invention should also be considered as the scope of protection of the present invention.

Claims

1. A wood charcoal layer crack repair agent, characterized in that, The invention is composed of the following components in parts by weight: 30-80 parts of polymerizable short-chain alkyl imidazole phosphate ionic liquid, 0.1-3.5 parts of initiator, 0.2-7.0 parts of crosslinking agent, 10-30 parts of PN flame retardant reinforcing agent, 2-20 parts of antioxidant, and 30-60 parts of deionized water; The polymerizable short-chain alkyl imidazole phosphate ionic liquid has the following structural formula: ； The initiator is azobisisobutylamidine hydrochloride; the cross-linking agent is N,N-methylenebisacrylamide; The PN flame retardant reinforcing agent is one or more of phosphoric acid, ammonium polyphosphate, monoammonium phosphate, diammonium phosphate, and phosphate ester oligomer; The antioxidant is one or more of butylated hydroxytoluene, talc, mica, kaolin, halloysite, montmorillonite, silica sol, SiO2, and boron compounds.

2. The wood charcoal layer crack repairing agent according to claim 1, characterized in that The polymerizable short-chain alkyl imidazole phosphate ionic liquid is prepared by the following method: 1) Pass nitrogen gas into the reaction vessel equipped with a spherical condenser to exhaust the air; 2) Add the weighed trimethyl phosphate and 1-vinylimidazole into the container and stir to mix evenly; 3) Heating in an oil bath to 100-120°C and maintaining the temperature for 1-3 hours, then lowering the temperature of the product to below 70°C while maintaining a nitrogen atmosphere and continuously stirring to obtain a deep red liquid product; 4) Slowly add ethyl acetate solution to the liquid product until the product turns into a light yellow solid, and filter to obtain a light yellow residue; The ethyl acetate solution washing was repeated 3-4 times; 5) Transfer the light yellow residue to a rotary evaporator and distill under reduced pressure in a 60°C water bath; 6) The dark red liquid product obtained after the reduced pressure distillation is placed in a vacuum drying oven and vacuum dried at 80°C for 24-48 hours to obtain a polymerizable short-chain alkyl imidazole phosphate ionic liquid.

3. The wood charcoal layer crack repairing agent according to claim 2, characterized in that The molar ratio of the trimethyl phosphate to 1-vinylimidazole is 1:0.5-1.

4. The method for preparing the wood charcoal layer crack repairing agent according to any one of claims 1 to 3, characterized in that: The initiator, the cross-linking agent, the PN flame retardant reinforcing agent, the antioxidant and the deionized water are added into the polymerizable short-chain alkyl imidazole phosphate ionic liquid and stirred evenly to prepare the wood charcoal layer crack repairing agent.

5. A method for repairing cracks in the wood charcoal layer, characterized in that: Utilize the repairing agent described in any one of claims 1-3.

6. The method for repairing cracks in the wood charcoal layer according to claim 5, characterized in that: include: Step 1: Decontamination of wood and wood materials; Step 2: applying the repair agent described in any one of claims 1 to 3 to the surface of the material described in step 1, or vacuum impregnating the material described in step 1 into the repair agent described in any one of claims 1 to 3; Step 3: Dry the material after step 2; Step 4: The dried material is polymerized.

7. The method for repairing cracks in the wood charcoal layer according to claim 6, characterized in that: include: Step 1: Decontamination of wood and wood materials; Step 2: Apply the prepared wood charcoal layer crack repair agent to the surface of the wood or wooden material, place it at room temperature for 6-10 hours, and then apply it again. Repeat this process until the liquid coating amount is 150-1000g / m 2 ; Step 3: Place the treated material in a drying kiln, raise the temperature to 40-60°C, and dry for 6-12 hours; Step 4: Raise the temperature to 70-120° C., maintain for 4-8 hours, and cool to room temperature to obtain modified wood and wood materials.

8. The method for repairing cracks in the wood charcoal layer according to claim 6, characterized in that: include: Step 1: Decontamination of wood and wood materials; Step 2: After decontamination, place the wood and wood materials into a treatment tank, evacuate to 0.1 MPa, and maintain for 30-120 minutes; add the prepared wood char layer crack repair agent into the tank so that the repair agent completely submerges the material; then adjust the pressure to 10-30 MPa and maintain for 0.5-6 hours; then vacuum treat at 0.1 MPa for 15-30 minutes; Step 3: Place the treated material in a drying kiln, raise the temperature to 40-60°C, and dry for 12-24 hours; Step 4: Raise the temperature to 70-120° C. and maintain for 4-8 hours; cool to room temperature to obtain modified wood and wood materials.

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