Functionally modified fire-retardant small-diameter lumber and method for making same

Abstract

The application discloses a kind of functional modification flame-retardant small-diameter wood and its preparation method, comprising: wood matrix, and three-dimensional flame-retardant structure is arranged in wood matrix inside;Preparation method is: S1, to small-diameter wood is pretreated and carries out drying treatment, to ensure that wood surface is clean and water content is appropriate;S2, after pretreatment, small-diameter wood is placed in alkali solution and is soaked, after taking out, rinse clean with clean water and dry in ventilation, the cellulose content of wood after treatment is determined;S3, select phosphoric acid lipid compound configuration flame retardant, using vacuum impregnation makes flame retardant penetrate into small-diameter wood, makes solution form gel in wood inside, and to small-diameter wood is aging treatment;S4, select anhydride preparation esterification agent, after aging, small-diameter wood is soaked into esterification agent, amino resin is added to it and is fully stirred and mixed after, wood is taken out and is dried, and functional modification flame-retardant small-diameter wood is obtained.The application improves flame retardancy, so that its mechanical property is enhanced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wood processing, in particular to a functional modified flame-retardant small-diameter wood and a preparation method thereof. BACKGROUND

[0002] Small-diameter wood generally refers to logs with a length of 2-6 meters and a diameter of 6-16 centimeters. Small-diameter wood belongs to the Pinaceae family and mainly grows in North America, Europe, Russia and other regions. It is a light yellow hard wood. In the fields of furniture manufacturing, interior decoration, etc., small-diameter wood has a wide range of applications.

[0003] Small-diameter wood has many advantages and application values. First, the wood structure of small-diameter wood is compact, with high hardness, wear resistance, corrosion resistance, water resistance, and is not prone to deformation and cracking. These characteristics make small-diameter wood have a wide range of uses in many fields, such as landscaping, greening, building decoration, home decoration, etc. In addition, small-diameter wood can also be used in papermaking, sugar making, etc.

[0004] However, the density of small-diameter wood is relatively low, resulting in more internal pores, which makes oxygen in the air more easily enter the wood interior, thereby promoting combustion; secondly, the water content of small-diameter wood is low, because the smaller wood surface area to volume ratio makes water evaporation faster, resulting in drier wood that is more flammable.

[0005] At the same time, small-diameter wood may be affected by different environmental influences and biochemical processes during growth due to its smaller diameter, and smaller trees contain more resin and less cellulose, and a small amount of cellulose cannot be completely carbonized at high temperatures, which affects the flame retardancy of the wood.

[0006] Finally, the growth cycle of small-diameter wood is usually short, which results in an internal structure that is not tight enough, thereby affecting its flame retardancy. SUMMARY

[0007] The present application overcomes the shortcomings of the prior art and provides a functional modified flame-retardant small-diameter wood and a preparation method thereof.

[0008] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: a preparation method of a functional modified flame-retardant small-diameter wood, comprising the following steps:

[0009] S1, wood pretreatment: selecting small-diameter wood with a diameter of 10-20 cm, pretreating the small-diameter wood and drying to ensure that the wood surface is clean and the water content is appropriate;

[0010] S2, cellulose determination: placing the pretreated small-diameter wood in an alkali solution with a concentration of 8%-11% for 24-30 hours, rinsing the surface of the small-diameter wood with clean water after taking it out, and drying it in a ventilated place, and determining the cellulose content of the treated wood;

[0011] S3, three-dimensional structure formation: select phospholipid compounds to configure 45%~50% of the flame retardant, using vacuum impregnation to make the flame retardant penetrate into the small diameter wood, make the solution form a gel inside the wood, and age the small diameter wood, the temperature during aging is 68~72℃, and the aging time is 3.5~4.1h;

[0012] S4, modified wood: select anhydride to prepare 53%~61% of the esterification agent, soak the aged small diameter wood into the esterification agent, add amino resin thereto and mix thoroughly for 30~45min, then take out the wood and dry at 65~76℃ for 4h to obtain the functional modified flame-retardant small diameter wood.

[0013] In a preferred embodiment of the present application, in the S1, the pretreatment and drying of the small diameter wood comprises the following steps:

[0014] S11, select wood without obvious pests, cracks and deformation from the small diameter wood, clean the surface of the wood with a soft brush and a non-corrosive cleaner to remove dust, soil and other impurities;

[0015] S12, place the cleaned small diameter wood in a well-ventilated dry room to avoid direct sunlight, and use a drying device to reduce the moisture content of the wood to 20%~30%, the drying temperature is 60℃~75℃, and the drying time is 36~48h;

[0016] S13, polish and polish the surface of the dried small diameter wood to remove the rough parts and small defects on the surface.

[0017] In a preferred embodiment of the present application, in the S2, the alkali solution is one of sodium hydroxide solution or potassium hydroxide solution.

[0018] In a preferred embodiment of the present application, in the S3, the specific steps of selecting phospholipid compounds to configure the flame retardant are as follows: dissolve the phospholipid compound in a solvent, configure it as a phospholipid compound solution with a concentration of 50%~60%, the mass ratio of the solvent to the phospholipid compound is 15:7.2~8.7, and stir uniformly to obtain the flame retardant solution.

[0019] In a preferred embodiment of the present application, in the S3, the amount of phospholipid compound used is 5%~10% of the mass of the small diameter wood.

[0020] In a preferred embodiment of the present application, in the S3, the phospholipid compound is triphosphonate or triethyl phosphate.

[0021] In one preferred embodiment of the present application, in the S3, the solvent is one of water, methanol or ethanol.

[0022] In one preferred embodiment of the present application, in the S4, the anhydride is one of maleic anhydride or phenolic anhydride.

[0023] In one preferred embodiment of the present application, in the S4, the amino resin includes one of urea-formaldehyde resin or phenol-formaldehyde resin.

[0024] The present application also provides a functionally modified flame-retardant small-diameter wood, comprising: a wood base body, and a three-dimensional flame-retardant structure arranged inside the wood base body.

[0025] The three-dimensional flame-retardant structure is obtained by vacuum impregnation to make the flame retardant penetrate into the small-diameter wood, gelation reaction, and aging treatment of the small-diameter wood, and then soaking the aged small-diameter wood into an esterification agent, adding an amino resin and fully stirring and mixing, and then drying treatment to obtain the functionally modified flame-retardant small-diameter wood.

[0026] The wood base body is obtained by pretreating and drying the small-diameter wood, soaking it in an alkali solution to increase the cellulose content, and then obtaining the small-diameter wood base body.

[0027] The present application solves the defects in the background art and has the following beneficial effects:

[0028] (1) The present application provides a functionally modified flame-retardant small-diameter wood and a preparation method thereof, which combines special flame-retardant treatment and wood modification treatment, not only improves the flame-retardant property, enhances the mechanical property, improves the weather resistance and durability, but also makes the wood product more stable during long-term use, reduces the frequency of maintenance and replacement, and prolongs the service life of the product.

[0029] (2) The present application can ensure the cleanliness of the wood surface and the moderate water content by careful pretreatment and drying treatment of the small-diameter wood, which provides good conditions for subsequent processing. This pretreatment not only improves the quality of the wood, but also enhances its stability, which helps to prolong the service life of the small-diameter wood.

[0030] (3) The present application improves the cellulose content in the small-diameter wood by alkali solution soaking treatment of the wood, which helps to enhance the mechanical property and flame-retardant property of the wood, and makes it more suitable for specific application scenarios.

[0031] (4)The present application effectively improves the flame-retardant performance of wood by using phosphoric acid lipid compounds as flame retardants and penetrating them into the interior of the wood to form a gel through vacuum impregnation. This three-dimensional flame-retardant structure can slow down the spread of fire when the wood is on fire, increasing the safety performance of the wood in a fire. This three-dimensional structure not only improves the flame-retardant performance, but also enhances the mechanical properties of the wood. The use of esterification agents and amino resins helps to form more stable chemical bonds, thereby improving the strength and hardness of the wood and making it more durable. Meanwhile, aging treatment can further promote the uniform distribution and solidification of the flame retardant in the interior of the wood, improving the durability of the flame-retardant effect.

[0032] (5)The present application can further improve the flame-retardant performance and stability of small-diameter wood by adding esterification agents and amino resins during the modification of the wood. Esterification can enhance the chemical bonding within the wood, improving the weather resistance and durability of the wood. The addition of amino resins can react with the hydroxyl groups in the wood to form a more stable structure, enhancing the mechanical strength and water resistance of the wood. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings described below are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings;

[0034] Figure 1 is a flow chart of the preferred embodiment of the present application. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0036] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be practiced in other manners different from those described herein, and therefore, the scope of protection of the present application is not limited by the specific embodiments disclosed below.

[0037] As Figure 1 shown, a functionally modified flame-retardant small-diameter wood and a preparation method thereof include the following steps:

[0038] S1, wood pretreatment: select small-diameter wood with a diameter of 10-20 cm, pretreat the small-diameter wood and dry it to ensure that the wood surface is clean and the moisture content is appropriate;

[0039] S2, cellulose determination: after pretreatment, the small-diameter wood is placed in an alkali solution with a concentration of 8-11% for 24-30h, then the small-diameter wood is washed clean and dried in a well-ventilated place, and the cellulose content of the treated wood is determined;

[0040] S3, three-dimensional structure formation: select a phosphoric acid ester compound to prepare 45-50% of a flame retardant, use vacuum impregnation to penetrate the flame retardant into the small-diameter wood, the vacuum degree is 0.06-0.09 MPa, the impregnation time is 35-55 min, the solution forms a gel inside the wood, and the small-diameter wood is aged, the aging temperature is 68-72℃, and the aging time is 3.5-4.1h;

[0041] S4, modified wood: select an anhydride to prepare 53-61% of an esterifying agent, soak the aged small-diameter wood in the esterifying agent, add amino resin and mix thoroughly for 30-45 min, then take out the wood and dry it at 65-76℃ for 4h to obtain functional modified flame-retardant small-diameter wood.

[0042] This preparation method combines special flame retardant treatment and wood modification treatment, not only improves the flame retardancy, enhances the mechanical properties, improves the weather resistance and durability, but also makes the wood product more stable during long-term use, reduces the frequency of maintenance and replacement, and prolongs the service life of the product.

[0043] In the S1, the pretreatment and drying of the small-diameter wood includes the following steps:

[0044] S11, select wood from small-diameter wood without obvious pests, cracks and deformation, clean the wood surface with a soft brush and a non-corrosive cleaner to remove dust, dirt and other impurities;

[0045] S12, place the cleaned small-diameter wood in a well-ventilated, sunlight-avoiding drying room, use drying equipment to reduce the moisture content of the wood to 20-30%, the drying temperature is 60-75℃, and the drying time is 36-48h;

[0046] S13, surface grinding and polishing of the dried small-diameter wood to remove rough parts and small defects on the surface.

[0047] This step is to ensure that the selected wood quality is excellent, and can withstand subsequent processing and treatment. Through careful pretreatment and drying of small-diameter wood, the cleanliness and moisture content of the wood surface can be ensured, providing good conditions for subsequent processing. This pretreatment not only improves the quality of the wood, but also enhances its stability, helping to extend the service life of small-diameter wood.

[0048] In the S2, the alkali solution is one of sodium hydroxide solution or potassium hydroxide solution. This step improves the cellulose content in small-diameter wood by soaking the wood in an alkali solution, which helps to enhance the mechanical properties and flame retardant properties of the wood, making it more suitable for specific application scenarios.

[0049] In the S3, the specific steps for selecting phosphorus-containing lipid compounds to configure the flame retardant are as follows: dissolve the phosphorus-containing lipid compounds in a solvent, configure a phosphorus-containing lipid compound solution with a concentration of 50% to 60%, the mass ratio of solvent to phosphorus-containing lipid compound is 15:7.2 to 8.7, and stir uniformly to obtain a flame retardant solution.

[0050] Phosphorus-containing lipid compounds have good flame retardant properties and can effectively improve the flame retardant properties of wood. By accurately controlling the ratio of phosphorus-containing lipid compounds and solvent, the concentration and stability of the flame retardant solution can be ensured. Uniform stirring can ensure the uniform distribution of the flame retardant in the wood.

[0051] In the S3, the amount of phosphorus-containing lipid compounds used is 5% to 10% of the mass of small-diameter wood. The amount of phosphorus-containing lipid compounds used, the vacuum degree during vacuum impregnation, and the impregnation time are all key factors to ensure the effect of flame retardant treatment. The appropriate amount of phosphorus-containing lipid compounds can make the wood have good flame retardant properties, and the appropriate vacuum degree and impregnation time can ensure that the flame retardant penetrates into the wood and improves the flame retardant effect.

[0052] In the S3, the phosphorus-containing lipid compounds are triphosphonate or triethyl phosphate, and the solvent is one of water, methanol or ethanol.

[0053] This step uses phosphorus-containing lipid compounds as flame retardants and penetrates into the wood by vacuum impregnation to form a gel, effectively improving the flame retardant properties of the wood. This three-dimensional flame retardant structure can slow down the spread of fire when the wood is on fire, increasing the safety performance of the wood in a fire. This three-dimensional structure not only improves the flame retardant properties, but also enhances the mechanical properties of the wood. The use of esterification agent and amino resin helps to form more stable chemical bonds, thereby improving the strength and hardness of the wood, making it more durable. Aging treatment can further promote the uniform distribution and solidification of the flame retardant in the wood, improving the durability of the flame retardant effect.

[0054] In the S4, the anhydride is one of maleic anhydride or phenolic anhydride, the amino resin includes one of urea-formaldehyde resin or phenol-formaldehyde resin, the anhydride can react with the amino resin to form a stable cross-linked structure, thereby improving the hardness, wear resistance and corrosion resistance of the wood.

[0055] In the modified wood stage, the addition of esterification agent and amino resin can further improve the flame retardant performance and stability of the small-diameter wood. The esterification reaction can enhance the chemical bonding inside the wood, improve the weather resistance and durability of the wood. The addition of amino resin can react with the hydroxyl groups in the wood to form a more stable structure, enhance the mechanical strength and water resistance of the wood.

[0056] A functionally modified flame-retardant small-diameter wood, comprising: a wood matrix, and a three-dimensional flame-retardant structure arranged inside the wood matrix, characterized in that,

[0057] The three-dimensional flame-retardant structure is obtained by vacuum impregnation to make the flame retardant penetrate into the small-diameter wood, gelation reaction, and aging treatment of the small-diameter wood, and then soaking the aged small-diameter wood into an esterification agent, adding an amino resin and fully stirring and mixing, and then drying treatment to obtain the functionally modified flame-retardant small-diameter wood.

[0058] The wood matrix is obtained by pretreating and drying the small-diameter wood, soaking it in an alkali solution to increase the cellulose content, and then drying the small-diameter wood.

[0059] Example 1

[0060] S1, wood pretreatment: select small-diameter wood with a diameter of 10 cm, wash it in clean water to remove surface impurities and dust. Then, put the small-diameter wood into a drying machine, start drying until the moisture content of the wood is reduced to 20%, the drying temperature is 60℃, and the drying time is 36h;

[0061] S2, cellulose determination: soak the pretreated small-diameter wood in a 8% concentration sodium hydroxide solution for 24 hours, rinse the surface of the small-diameter wood with clean water after taking it out, and dry it in a well-ventilated place. Use MO220 wood moisture tester to determine the cellulose content of the treated wood;

[0062] S3, three-dimensional structure formation: select tripolyphosphate as the flame retardant, configure it into a solution with a concentration of 45%. Then, put the small-diameter wood into a vacuum impregnation tank, and make the flame retardant penetrate into the small-diameter wood under the condition of vacuum degree of 0.06MPa; age the small-diameter wood at a temperature of 68℃ for 3.5h, so that the solution undergoes gelation reaction inside the wood;

[0063] S4, modified wood: maleic anhydride is selected as the esterifying agent, which is configured into a solution with a concentration of 53%. Then, the aged small-diameter wood is soaked into the esterifying agent, amino resin is added thereto and fully stirred and mixed for 30 min, the wood is taken out and dried at a temperature of 60°C for 4 h to obtain the functionally modified flame-retardant small-diameter wood.

[0064] Example 2

[0065] S1, wood pretreatment: small-diameter wood with a diameter of 15 cm is selected, which is washed in clean water to remove impurities and dust on the surface. Then, the small-diameter wood is placed in a drying machine to start drying until the water content of the wood is reduced to 25%, the drying temperature is 70°C, and the drying time is 42 h;

[0066] S2, cellulose determination: the pretreated small-diameter wood is soaked in a sodium hydroxide solution with a concentration of 10% for 27 h, the small-diameter wood is taken out and washed with clean water to clean the surface, and is dried in a ventilated place, and a MO220 wood moisture tester is used to determine the cellulose content of the treated wood;

[0067] S3, three-dimensional structure formation: tripolyphosphate is selected as the flame retardant, which is configured into a solution with a concentration of 48%. Then, the small-diameter wood is placed in a vacuum impregnation tank, and the flame retardant is allowed to penetrate into the small-diameter wood under the condition of a vacuum degree of 0.08 MPa; the small-diameter wood is aged at a temperature of 70°C for 3.8 h to allow the solution to undergo gelation reaction inside the wood;

[0068] S4, modified wood: maleic anhydride is selected as the esterifying agent, which is configured into a solution with a concentration of 57%. Then, the aged small-diameter wood is soaked into the esterifying agent, amino resin is added thereto and fully stirred and mixed for 37 min, the wood is taken out and dried at a temperature of 71°C for 4 h to obtain the functionally modified flame-retardant small-diameter wood.

[0069] Example 3

[0070] S1, wood pretreatment: small-diameter wood with a diameter of 20 cm is selected, which is washed in clean water to remove impurities and dust on the surface. Then, the small-diameter wood is placed in a drying machine to start drying until the water content of the wood is reduced to 30%, the drying temperature is 75°C, and the drying time is 48 h;

[0071] S2, cellulose determination: the pretreated small-diameter wood is soaked in a sodium hydroxide solution with a concentration of 11% for 30 h, the small-diameter wood is taken out and washed with clean water to clean the surface, and is dried in a ventilated place, and a MO220 wood moisture tester is used to determine the cellulose content of the treated wood;

[0072] S3, three-dimensional structure formation: trisphosphate is selected as the flame retardant, which is configured into a solution with a concentration of 50%. Then, the small-diameter wood is put into a vacuum impregnation tank, and the flame retardant is allowed to penetrate into the small-diameter wood under the condition that the vacuum degree is 0.09 MPa; the small-diameter wood is subjected to aging treatment at a temperature of 72°C for 4.1 h, so that the solution is subjected to gelation reaction inside the wood;

[0073] S4, modified wood: maleic anhydride is selected as the esterifying agent, which is configured into a solution with a concentration of 61%. Then, the small-diameter wood after aging is soaked into the esterifying agent, and the amino resin is added thereto and subjected to sufficient stirring and mixing for 45 min, and the wood is taken out and subjected to drying treatment at a temperature of 76°C for 4 h, to obtain the functionally modified flame-retardant small-diameter wood.

[0074] Comparative Example 1

[0075] The same as Example 1 is not repeated, and the difference is that:

[0076] After the wood is pretreated, step S2 is deleted, and step S3 is directly performed.

[0077] Comparative Example 2

[0078] The same as Example 1 is not repeated, and the difference is that:

[0079] After the cellulose content of the treated wood is determined, step S3 is deleted, and step S4 is directly performed.

[0080] Comparative Example 3

[0081] The same as Example 1 is not repeated, and the difference is that:

[0082] In this comparative example, the flame retardant is directly coated on the surface of the small-diameter wood.

[0083] Experimental Example 1

[0084] The following tests are performed on Examples 1-3 and Comparative Examples 1-3 in this experimental example:

[0085] (1) Determination of cellulose content: the cellulose content in the small-diameter wood is measured using the LY / T 2151-2013 standard;

[0086] (2) Determination of flame-retardant level: the flame-retardant level is determined according to the UL94-2009 standard;

[0087] (3) Determination of limiting oxygen index: the limiting oxygen index is determined according to the GB / T2406.2-2009 standard;

[0088] (4) Determination of tensile strength: the tensile strength is determined according to the ASTM D638-08 standard;

[0089] (5) Determination of Bending Strength and Bending Modulus: The bending strength and bending modulus were determined according to the standard of ASTM D790-03.

[0090] The measured experimental data were summarized in Table 1.

[0091] Table 1 Summary of Small-diameter Wood Performance Data

[0092]

[0093]

[0094] According to the provided data, we can analyze the small-diameter wood performance of Examples 1-3 and Comparative Examples 1-3 in detail and draw corresponding conclusions:

[0095] (1) Cellulose Content

[0096] The small-diameter wood of Example 3 has the highest cellulose content (52.1%), followed by Example 2 (47.9%) and Example 1 (45.3%). The cellulose content of the comparative examples is generally low, among which the cellulose content of Comparative Example 3 is the lowest, only 15.3%. Cellulose is the main component of wood, and its content directly affects the strength and durability of wood. Therefore, the small-diameter wood of Example 3 performs best in terms of cellulose content.

[0097] (2) Flame Retardant Level

[0098] The small-diameter wood of Examples 1-3 all reached V-0 level, which is the highest flame retardant level, indicating that these small-diameter woods have good flame retardant performance. The flame retardant level of the small-diameter wood of Comparative Examples 1-3 is lower, among which the flame retardant level of Comparative Example 3 is the lowest, which is V-2 level. This shows that the method of Examples 1-3 is more effective in flame retardant treatment.

[0099] (3) Limiting Oxygen Index

[0100] The small-diameter wood of Example 3 also performs best, reaching 49%, while Examples 1 and 2 are 47% and 43% respectively. The limiting oxygen index is an important indicator to measure the flame retardant performance of materials, the higher the value, the better the flame retardant performance of the material. The limiting oxygen index of the small-diameter wood of the comparative examples is generally low, especially Comparative Example 3, which is only 29%.

[0101] (4) Tensile Strength and Bending Strength

[0102] The small-diameter woods of Examples 1-3 all showed higher strength, among which the small-diameter wood of Example 3 reached the highest values in tensile strength and bending strength, which were 33.3 MPa and 39.5 MPa, respectively. The small-diameter wood of the comparative example performed relatively poorly in these two indicators, especially Comparative Example 3, with tensile strength and bending strength of 25.1 MPa and 31.5 MPa, respectively, which were significantly lower than those of the small-diameter woods of the examples.

[0103] (5) Bending modulus

[0104] The small-diameter woods of Examples 1-3 also showed better performance, among which the bending modulus of Example 2 was the highest, which was 8.9 GPa. The bending modulus of the small-diameter wood of the comparative example was lower, and the bending modulus of Comparative Example 3 was the lowest, which was 6.7 GPa.

[0105] Based on the above analysis, we can draw the following conclusions:

[0106] The small-diameter wood of Example 3 performed best in cellulose content, flame-retardant grade, limiting oxygen index, tensile strength, bending strength, and bending modulus, indicating that its pretreatment and modification process was the most effective, which could significantly improve the overall performance of the small-diameter wood.

[0107] Although the small-diameter woods of Examples 1 and 2 were slightly inferior to Example 3 in some performance indicators, they also reached a high level, showing good overall performance.

[0108] The small-diameter wood of the comparative example generally performed poorly in various performance indicators, especially Comparative Example 3, which was significantly lower than the small-diameter wood of the example,

[0109] By comparing the data of the examples and the comparative example, it can be seen that the increase in cellulose content and the formation of a three-dimensional cross-linked structure are crucial for improving the flame-retardant performance and mechanical strength of the small-diameter wood. Therefore, in order to obtain small-diameter wood with excellent performance, the pretreatment, cellulose determination, three-dimensional structure formation, and modification treatment should be strictly carried out according to the steps in Examples 1-3. At the same time, these data also provide an important reference for further optimizing the wood modification process.

[0110] Based on the ideal embodiments of the present application, through the above description, relevant personnel can make various changes and modifications without deviating from the scope of the technical idea of the present application. The technical scope of the present application is not limited to the contents of the specification, and the technical scope must be determined according to the scope of the claims.

Claims

1. A method for producing a functionally modified fire-retardant small-diameter log, characterized by, The method comprises the following steps: S1, wood pretreatment: selecting small-diameter wood with a diameter of 10-20 cm, pretreating and drying the small-diameter wood to ensure that the wood surface is clean and the water content is appropriate; S2, cellulose determination: placing the pretreated small-diameter wood in an alkali solution with a concentration of 8%-11% for 24-30 h, rinsing the surface of the small-diameter wood with clean water after taking it out, and airing it in a ventilated place to dry, and determining the cellulose content of the treated wood; S3, three-dimensional structure formation: selecting a phosphoric acid ester compound to prepare a 45%-50% flame retardant, using vacuum impregnation to make the flame retardant penetrate into the small-diameter wood, making the solution form a gel inside the wood, and aging the small-diameter wood, the aging temperature is 68-72°C, and the aging time is 3.5-4.1 h; wherein the specific steps of preparing the flame retardant by selecting the phosphoric acid ester compound are as follows: dissolving the phosphoric acid ester compound in a solvent, preparing a phosphoric acid ester compound solution with a concentration of 50%-60%, the mass ratio of the solvent to the phosphoric acid ester compound is 15:7.2-8.7, stirring uniformly, and then obtaining the flame retardant solution, the amount of the phosphoric acid ester compound used is 5%-10% of the mass of the small-diameter wood; S4, modified wood: selecting an acid anhydride to prepare a 53%-61% esterifying agent, soaking the aged small-diameter wood in the esterifying agent, adding an amino resin thereto and fully stirring and mixing for 30-45 min, taking out the wood and drying it at 65-76°C for 4 h to obtain functional modified flame-retardant small-diameter wood.

2. A process for the preparation of functionally modified fire-retardant small-dimension wood according to claim 1, characterized by: In the S1, the pretreatment and drying of the small-diameter wood comprises the following steps: S11, selecting wood without obvious pests, cracks and deformation from the small-diameter wood, using a soft brush and a non-corrosive cleaner to clean the surface of the wood to remove dust and soil; S12, placing the cleaned small-diameter wood in a dry room with good ventilation and avoiding direct sunlight, using a drying device to reduce the water content of the wood to 20%-30%, the drying temperature is 60-75°C, and the drying time is 36-48 h; S13, surface polishing and polishing of the dried small-diameter wood to remove rough parts and small defects on the surface.

3. A method of producing functionally modified fire-retardant small-diameter lumber according to claim 1, characterized by: In the S2, the alkali solution is one of a sodium hydroxide solution or a potassium hydroxide solution.

4. A process for the preparation of functionally modified fire-retardant small-dimension wood according to claim 1, characterized by the fact that: In the S3, the phosphoric acid ester compound is triphosphoric acid ester or triethyl phosphate.

5. The method for preparing functionally modified fire-retardant small-diameter lumber according to claim 1, characterized by: In the S3, the solvent is one of water, methanol or ethanol.

6. A process for the preparation of functionally modified fire-retardant small-dimension wood according to claim 1, characterized by: In the S4, the acid anhydride is one of maleic anhydride or phenolic anhydride.

7. The method for preparing functionally modified flame-retardant small-diameter wood according to claim 1, characterized in that: In the S4, the amino resin includes one of urea-formaldehyde resin or phenol-formaldehyde resin.

8. A functionally modified fire-retardant small-dimension log prepared by the method of any one of claims 1 to 7, comprising: The wood matrix and the three-dimensional flame-retardant structure arranged inside the wood matrix are characterized in that, the three-dimensional flame-retardant structure is obtained by vacuum impregnation to make the flame retardant penetrate into the small-diameter wood, gelation reaction, aging of the small-diameter wood, soaking the aged small-diameter wood in an esterifying agent, adding an amino resin and fully stirring and mixing, and drying to obtain functional modified flame-retardant small-diameter wood; The wood matrix is a small-diameter wood matrix obtained by pre-treating and drying small-diameter wood, and then soaking the small-diameter wood in an alkali solution to increase the cellulose content.

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