Flame retardant composition for wood and wood-based materials using a compound of high concentration of boron and phenolic resin, flame retardant wood or wood-based material using the same, and method for producing the same

Abstract

The flame retardant composition for wood and wood materials according to the present invention is characterized by containing boric acid, sodium borate, phenolic resin, and water. The method for producing flame retardant wood or wood materials according to the present invention is characterized by comprising the steps of S1) preparing wood or wood materials, S2) producing a flame retardant for wood consisting of a compound of phenolic resin, boric acid, and sodium borate, S3) injecting the flame retardant for wood consisting of a compound of phenolic resin, boric acid, and sodium borate obtained in step S2) into the wood or wood materials, and S4) drying and curing the injected wood or wood materials.

Description

[Technical Field]

[0001] The present invention relates to a flame retardant composition for wood and wood-based materials, and flame retardant wood and wood-based materials using the same. More specifically, the present invention relates to a flame retardant composition for wood and wood-based materials, which is composed of inorganic chemicals, i.e., boric acid and sodium borate, at high concentrations, and a phenolic resin, and a method for producing flame retardant wood or wood-based materials using the same, which improves the reduced adhesive strength and moisture resistance caused by inorganic treatment. [Background technology]

[0002] Wood is an environmentally friendly, human-friendly, and sustainable material, and has been widely used for household items, tools, furniture, and wooden buildings from prehistoric times to the present day, and has a close relationship with humans. Furthermore, with the recent advancement of global warming, wood, which has been called "canned carbon dioxide," has once again come into the spotlight, and the use of wooden buildings that can be used for a long period of time is being promoted. However, such wood has the disadvantage of being prone to rot and combustion. To compensate for these disadvantages, various researches on flame retardancy are being conducted, particularly to impart fire resistance.

[0003] Since the discovery of their fire-resistant properties by Gay-Lussac in 1823, boric acid and sodium borate have been widely used for the flame retardant treatment of wood, paper, and wood-based materials, as a wood preservative, and to control termites. In the 1970s, a mixture of boric acid, borax, and inorganic salts was used by the American AWPA under the names Minalith and Pyresote, and was also introduced early on in a Korean university textbook (Lee et al., 1981). However, due to their low solubility, boron-based agents have been used at low concentrations of 8% (wt%) or less (Song et al. (2013), Jeong et al. (2018), Korean Patent No. 10-2015-012482), and have only been used as auxiliary agents for fire retardants (Lee et al. (1981), Wood Engineering, Hyangmun Co., Ltd., Song Dong-won et al. (2013): 3% each of boric acid and borax, Development of manufacturing technology for environmentally friendly fire-retardant wood. Research Reports of the Institute of Forest Science 13-20, Jeong Yong-jin et al.: Fire Sci. Eng., Vol. 32, No. 2, pp. 1-6, 2018: 4%) (Korean Patent No. 10-2015-0124482: 0.4-1 wt% boric acid, 1-5 wt% sodium borate; Korean Patent No. 10-2021-0064800: 0.6-0.7 wt% boric acid, 0.1-1 wt% borax).

[0004] The main reasons for this are: first, their solubility in water is low at room temperature (boric acid 4.72 g, borax 4.71 g, 20°C); second, when the temperature is raised to perform high-temperature dissolution treatment to increase solubility, precipitated crystals form on the wood surface, hindering penetration and causing wood surface contamination through efflorescence (for example, solubility at 80°C: boric acid 23.6 g, borax 44.3 g); third, when treated wood comes into contact with water, the chemicals become highly leaching (exudable); and fourth, it is known that treating wood with boric acid or sodium borate hinders bond formation, resulting in a decrease in strength, not only between identical materials but also between different materials (Laks et al. 1990). Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention was developed to solve the above-mentioned problems, and its object is to provide a high-concentration phenol-boron-based flame retardant composition for wood that compensates for the drawback of wood being vulnerable to fire, maintains a clean surface condition even after treatment, and imparts dimensional stability and flame retardancy without leaching out due to water, as well as flame-retardant wood using the same and a method for producing the same. [Means for solving the problem]

[0006] The flame retardant composition for wood and wood-based materials according to the present invention is characterized by containing boric acid, sodium borate, and a water-soluble phenolic resin.

[0007] The composition contains, on a solids basis, 16 to 36 wt% of the phenolic resin, 8 to 18 wt% of boric acid, 10 to 22 wt% of sodium borate, and 18 to 40 wt% of boric acid-sodium borate. Hereinafter, the contents of the constituent components are based on the solids.

[0008] The phenolic resin is a liquid resol type produced by adding phenol, formalin, and water to a resin reactor, adjusting the pH to 10.7 to 11.0 with sodium hydroxide (NaOH), and reacting them.

[0009] The phenolic resin is a liquid resol type prepared by adding the phenol and the formalin to the resin reactor in a molar ratio of phenol:formalin (35%) = 1:1.63 to 2.4, adjusting the pH to 10.7 to 11.0 with sodium hydroxide (NaOH), and reacting at 70 to 80°C.

[0010] The composition further contains resorcinol or bisphenol, which is a liquid resol type that can be co-condensed with phenol to produce a resin.

[0011] The resorcinol is contained in an amount ranging from 10 to 40 wt %.

[0012] The composition is also characterized by containing 23 to 33 wt% of resorcinol and 15 to 21 wt% of phenolic resin, with a resorcinol-phenolic resin content in the range of 38 to 54 wt%, and 6.8 to 10.9 wt% of boric acid and 8.5 to 13.7 wt% of sodium borate, with a boric acid-sodium borate content in the range of 15.3 to 24.6 wt%.

[0013] In addition, the boric acid and sodium borate are mixed to produce a boric acid-sodium borate mixture, which is prepared by adding 25.53 wt% of boric acid and 31.91 wt% of sodium borate (borax) to water to prepare a boric acid-sodium borate solution, and heating the mixture to 90°C to 100°C to produce a transparent, water-soluble boric acid-sodium borate mixture, which is then mixed with a phenolic resin and reacted.

[0014] The method for producing flame-retardant wood or a flame-retardant wood material according to the present invention comprises the steps of: S1) preparing wood or wood-based material; S2) preparing a wood flame retardant comprising a mixture of phenolic resin, boric acid and sodium borate; S3) injecting the wood flame retardant obtained in step S2) into the wood or wood-based material; and S4) drying and hardening the impregnated wood or wood-based material; The present invention is characterized by comprising:

[0015] Furthermore, the step S2) includes the steps of: S2-1) producing a phenolic resin; S2-2) mixing boric acid and sodium borate in a solvent to produce a boric acid-sodium borate mixture; and S2-3) mixing and reacting the boric acid-sodium borate mixture with the phenolic resin.

[0016] The method further includes a step S5) of carrying out a heat pressing process according to the wood material to produce a final wood material.

[0017] The wood or wood-based material is characterized by being a veneer, board, particle, strand, or fiber obtained from logs, as well as plywood, laminated veneer lumber (LVL), laminated timber, structural cross-laminated timber (CLT), particle board, strand board, and fiberboard made from these.

[0018] Furthermore, in the step S2-1) of producing a phenolic resin, 94 g (1 mole) of phenol, 139.5 to 205.7 g (1.63 to 2.4 moles) of 35% formalin, and 14 to 20 g of water are added to a resin reactor, the pH is adjusted to 10.7 to 11.0 with sodium hydroxide (NaOH), and the reaction is carried out at 70 to 80°C to obtain a liquid resol type.

[0019] In addition, in step S2-2), boric acid and sodium borate are added to water and heated to 90-100°C to produce a boric acid-sodium borate mixture that dissolves well in water until it becomes transparent, and then in step S2-3), the produced phenolic resin is mixed with 16-36 wt% phenolic resin, 8-18 wt% boric acid, 10-22 wt% sodium borate, or 18-40 wt% boric acid-sodium borate, and reacted.

[0020] In addition, in the step S2), after producing a compound of phenolic resin, boric acid, and sodium borate, resorcinol is added to the compound of phenolic resin, boric acid, and sodium borate to produce a flame retardant for wood.

[0021] In the step S3), the injection method is characterized by diffusion and penetration under normal pressure.

[0022] In step S3), the injection method is a pressurization / depressurization method, and the main pressure is 10 to 25 kg / cm 2 The method is characterized in that the treatment is carried out at 400°C for 30 to 120 minutes.

[0023] In the step S3), before and after the main pressurization, pre-evacuation is performed for 30 minutes and post-evacuation is performed for 10 to 30 minutes.

[0024] The method is also characterized by including a hardening step in which the wood or wood material injected in step S4) is stabilized at room temperature, dried at 50 to 70°C for a certain period of time, and then hardened at 100 to 150°C.

[0025] In step S5), the veneer is manufactured as plywood or laminated veneer lumber (LVL), the board is manufactured as laminated timber or structural cross-laminated timber (CLT), the particles are manufactured as particle board, the strands are manufactured as strand board, and the fibers are manufactured as fiberboard.

[0026] The flame retardant composition of the present invention as described above uses an inorganic agent, but the phenolic resin improves the adhesive strength loss and moisture vulnerability caused by inorganic treatment. Furthermore, the reaction compound of a high-concentration boric acid-sodium borate mixture with a phenolic resin provides a flame retardant composition for wood that can be stored at room temperature (25-30°C) for up to two months. Furthermore, when the inorganic agent of boric acid-sodium borate is used as a fire-resistant agent, it can be used as the main agent (fire-resistant adhesive) at a high concentration of up to 40%, unlike the conventional method in which it is used as an auxiliary agent at a concentration of 8% (wt%) or less. Therefore, a flame retardant composed of a reaction compound of a high-concentration boric acid-sodium borate mixture with a phenolic resin can be used as an adhesive that maximizes the fire resistance of wood. [Effects of the Invention]

[0027] According to the present invention, a flame retardant composition for wood, flame retardant wood, and a method for producing the same are provided, which improve the deterioration of adhesive strength and the moisture-sensitive properties, are less susceptible to leaching by water, have high dimensional stability, and have improved flame retardancy. [Brief explanation of the drawings]

[0028] [Figure 1] Figure 1 is a photograph showing wood that has been flame-retardant treated in an example of the present invention. The wood pattern is as clear as that of untreated wood. [Figure 2] Figure 2 is a photograph comparing untreated and flame-retardant treated boards before and after a leaching test (KS M 1701). [Figure 3] Figure 3 is a photograph comparing untreated particleboard and flame-retardant treated particleboard before and after a leaching test (KS M 1701-2018). In the leaching test for untreated particleboard, as shown on the right of 1, the thickness swelling rate was 48%, indicating a large expansion in thickness, whereas the flame-retardant treated particleboard (right of 2) showed a thickness swelling rate of 12%, indicating very high dimensional stability. [Figure 4]4 shows the surface condition of wood that has been flame-retardant treated in an example of the present invention, as a result of an ignition test using a cone calorimeter. It can be seen that a carbonized layer has formed on the surface due to the high temperature, but the back surface is in a clean condition. [Figure 5] FIG. 5 is a flowchart showing the steps for producing flame-retardant wood or wood-based material according to the present invention. [Figure 6] 6 to 14 are graphs showing the results of the total heat release rate (THR) and heat release rate (HRR) of wood that has been flame-retardant treated in the examples of the present invention, measured in a performance test using a cone calorimeter in accordance with KS F ISO 5660-1. Both results meet the flame-retardant grade or higher. [Figure 7] Same as above [Figure 8] Same as above [Figure 9] Same as above [Figure 10] Same as above [Figure 11] Same as above [Figure 12] Same as above [Figure 13] Same as above [Figure 14] Same as above DETAILED DESCRIPTION OF THE INVENTION

[0029] The present invention will be described in detail below. The terms used in this specification and claims are not limited to their dictionary meanings or ordinary meanings, but should be interpreted as meanings that are appropriate to the technical content of the present invention.

[0030] The flame retardant composition for wood and wood-based materials according to the present invention contains boric acid, sodium borate, a water-soluble phenolic resin, and water.

[0031] The flame retardant composition contains 16 to 36 wt% of phenolic resin (solid content), 8 to 18 wt% of boric acid (solid content), 10 to 22 wt% of sodium borate (solid content), and 18 to 40 wt% of boric acid-sodium borate (total solid content).

[0032] The phenolic resin is a liquid resol type, and the flame retardant composition according to the present invention may further contain resorcinol or bisphenol, which is a liquid resol type that can be co-condensed with phenol to produce a resin.

[0033] The resorcinol content in the flame retardant composition may be 10 to 40 wt %.

[0034] The flame retardant composition may contain 23 to 33 wt% of resorcinol resin (solid content) and 15 to 21 wt% of phenol resin (solid content), with a resorcinol-phenol resin (total solid content) in the range of 38 to 54 wt%, and 6.8 to 10.9 wt% of boric acid (solid content) and 8.5 to 13.7 wt% of sodium borate (solid content), with a boric acid-sodium borate (total solid content) in the range of 15.3 to 24.6 wt%.

[0035] Boric acid and sodium borate are mixed to produce a boric acid-sodium borate mixture. The boric acid-sodium borate mixture can be prepared, for example, as a boric acid-sodium borate solution by adding 25.53 wt % boric acid and 31.91 wt % sodium borate (borax) to water and heating the mixture to 90°C to 100°C to produce a transparent boric acid-sodium borate mixture that is highly soluble in water, which can then be mixed with a phenolic resin to cause a reaction.

[0036] The method for producing the flame retardant composition for wood and wood-based materials of the present invention is described in detail below. The flame retardant agent comprising the flame retardant composition for wood and wood-based materials of the present invention is produced through three steps: a step of producing a phenolic resin, a step of mixing boric acid and sodium borate in a solvent to produce a boric acid-sodium borate mixture, and a step of mixing and reacting the boric acid-sodium borate mixture with the phenolic resin.

[0037] When producing phenolic resin, phenol, formalin, and distilled water are charged into a reactor at room temperature, the pH is adjusted, and the mixture is reacted at a predetermined temperature for a predetermined time to produce a resol-type phenolic resin.

[0038] Phenol and formalin are added to a resin reactor in a molar ratio of phenol:formalin = 1:1.63-2.4. In one specific example, 94 g (1 mole) of phenol, 139.5-205.7 g (1.63-2.4 moles) of formalin (35%), and 14-20 g of distilled water are added to the reactor at room temperature, the pH is adjusted to 10.7-11 with NaOH, and the reaction is carried out at a temperature of 70-80°C for 1 hour. This results in a very high pH, ​​a low temperature, and a short reaction time, resulting in a resol-type phenolic resin (resin solids content: 51-53.4%, pH: 10.7-10.98, viscosity: 32-38.4 cps) as an intermediate product.

[0039] Moreover, phenol derivatives such as resorcinol and bisphenol may be used in place of phenol, and may be mixed with phenol to produce a resorcinol-phenol co-condensation resin.

[0040] In the step of preparing the boric acid-sodium borate mixture, boric acid and sodium borate (borax) are added and heated to a predetermined temperature to prepare a boric acid-sodium borate mixture that dissolves well in water until it becomes transparent.

[0041] In one specific example, a boric acid-sodium borate solution is produced by adding 25.53 wt% boric acid and 31.91 wt% sodium borate (borax) to water (42.56 wt%) and heating the mixture to 90°C to 100°C until it becomes transparent, producing a boric acid-sodium borate mixture that dissolves well in water.

[0042] In the step of mixing and reacting the boric acid-sodium borate mixture with the phenolic resin, the boric acid-sodium borate mixtures prepared as described above and the phenolic resin are mixed and reacted.

[0043] In this example, the phenolic resin produced above is mixed with the following ingredients while maintaining the temperature at 60°C: phenolic resin solids content 16-36 wt%, boric acid solids content 8-18 wt%, sodium borate solids content 10-22 wt%, and total boric acid-sodium borate solids content 18-40 wt%, and the mixture is allowed to react for 2 hours to obtain a water-resistant flame retardant composition for wood. This liquid composition can be stored for up to 2 months at a temperature of 20-30°C.

[0044] Furthermore, it is also possible to produce a flame retardant composition consisting of a water-resistant resorcinol-phenolic resin-boric acid-sodium borate mixture by adding 10 to 40 wt % of resorcinol to the phenolic resin-boric acid-sodium borate mixture prepared as described above while maintaining the mixture at 60°C, allowing the mixture to react for an additional 2 hours, and then storing the mixture at a temperature of 20 to 30°C.

[0045] The phenol-resorcinol resin-boric acid-sodium borate mixture or resorcinol-phenolic resin-boric acid-sodium borate mixture produced in this manner has a low phenolic resin solids content and a low resorcinol resin solids content, and if the combined phenolic resin solids and resorcinol solids content is 30 wt% or less, the flame retardancy and dimensional stability of the flame-retardant-treated product are emphasized over adhesion. On the other hand, if the combined phenolic resin solids and resorcinol solids content is 40 wt% or more, the adhesive properties are primary, with the flame retardancy being a secondary benefit. Therefore, the mixture can be cold- or hot-pressed with the addition of a hardener and filler, similar to the adhesives used in the manufacture of plywood and laminated lumber. Because this mixture is used like a typical adhesive for wood materials, the process is simple, unlike the complex process of flame retardant injection. During the manufacture of plywood or laminated lumber, a portion of the liquid flame-retardant composition spreads to the wood at the interface just before the glue line is formed. Furthermore, the adhesive layer itself forms a flame-retardant layer. Therefore, the more adhesive layers there are, the more flame-retardant layers there are, giving plywood with more flame-retardant layers an advantage over laminated lumber. Therefore, the more flame-retardant adhesive layers there are in flame-retardant plywood, the longer its fire resistance lasts. Therefore, when such flame-retardant plywood is used not only in plywood but also in CLT, which is used as a structural material, it can fully fulfill its role as a fire-resistant structure, maintaining fire resistance for a certain period of time depending on the application or components.

[0046] Further, the flame-retardant wood or wood material according to the present invention and the method for producing the same will be described below. Figure 5 is a flow chart showing the steps for producing the flame-retardant wood or wood material according to the present invention.

[0047] The method for producing flame-retardant wood or wood-based materials according to the present invention includes the steps of: S1) preparing wood or wood-based materials; S2) producing a flame retardant for wood consisting of a compound of phenolic resin, boric acid, and sodium borate; S3) injecting the flame retardant for wood consisting of a compound of phenolic resin, boric acid, and sodium borate obtained in step S2) into the wood or wood-based materials; and S4) drying and curing the injected wood or wood-based materials.

[0048] Step S2) also includes the steps of producing a phenolic resin, mixing boric acid and sodium borate in a solvent to produce a boric acid-sodium borate mixture, and mixing and reacting the boric acid-sodium borate mixture with the phenolic resin.

[0049] The method may further include a step of S5) performing a heat pressing process depending on the wood material (particles, fiber, veneer, board) to manufacture a final wood material.

[0050] In the method for manufacturing flame-retardant wood and wood-based materials according to the present invention, first, wood or wood-based materials are prepared. Wood is classified into various wood materials depending on the intended use. Wood can be sawn into boards or lumber, shaved or milled into thin boards, i.e., veneers, or ground or crushed into particles or fibers. These wood materials (particles, fiber, veneer, board) are used to make wood-based materials, such as particleboard for particles, fiberboard for fibers, OSB for strands, plywood or laminated veneer lumber (LVL) for veneers, and glue-laminated timber (glulam) or cross-laminated timber (CLT) for construction. These materials are treated with flame retardants during the manufacturing process (mixing, injection, painting, covering).

[0051] Next, in the step of preparing a flame retardant agent, the above-mentioned flame retardant composition for wood and wood-based materials is produced.

[0052] Next, in the step of injecting the compound of phenolic resin, boric acid, and sodium borate into the wood or wood-based material, the injection method may include, depending on the wood material and its thickness, a method of diffusion and penetration at room temperature, a pressurization method, or a method of performing both evacuation and pressurization treatment.

[0053] The boards are pressed only at 10 to 25 kg / cm depending on the species of wood. 2 or by using the pressure reduction method, pre-evacuation (0.08 MPa) for 30 minutes and pressure reduction at 15 to 25 kg / cm 2 The pressure is 10 to 25 kgf / cm for 1 hour, followed by post-exhaust (0.08 MPa) for 10 to 30 minutes. The temperature during this process is generally between room temperature and 60°C. Ready-made plywood, laminated veneer lumber, and glued laminated lumber are treated in the same manner as for board materials. For veneers, the pressure is 10 to 25 kgf / cm depending on the tree species. 2 The treatment is carried out for 30 to 120 minutes at a pressure of 1000 kJ / cm. The particles or fibers are mixed with the flame retardant in a mixer while rotating for 30 minutes, allowing the particles or fibers to be injected and applied by friction and internal diffusion.

[0054] Next, the wood or wood-based material that has been injected with a flame retardant is dried and cured at 50 to 70°C, preferably 60°C, for a certain period of time depending on the wood material, species, heartwood, and thickness, followed by a step of stabilizing the material through drying and curing, and a step of curing the phenolic resin in the flame retardant at 100 to 150°C. For example, boards are dry-cured at 60°C for 24 to 28 hours and then cured at 105°C for 24 hours to produce flame-retardant wood. Because veneers are thin, for example, they are dry-cured at 60°C for 12 to 24 hours and then cured at 105°C for 6 to 12 hours to produce flame-retardant veneers. For example, particles or fibers are dried at 60°C for 12 to 24 hours and then cured at 105°C for 30 minutes to 2 hours.

[0055] Of the dried and hardened wood and wood-based materials, wood and boards may be used as they are after the above-mentioned treatment, but veneers, particles, fibers, and even boards may be subjected to the next step, a heat-pressing process, to produce the final wood material.

[0056] The treated boards are used to make laminated timber or structural cross-laminated timber (CLT), and resorcinol adhesives or phenol-resorcinol co-condensation adhesives may be used. The treated veneer is then used to make plywood and laminated veneer lumber (LVL) using adhesives. The treated particles or fibers are then used with adhesives to produce particleboard or fiberboard through a standard hot-press process. For example, flame-retardant treated particles are mixed with 10% melamine resin (53% solids) and 3% 20% NH4Cl solution as a hardener, and after forming into a mat, the mixture is heated in a hot-press oven at 175°C and 45-30-20 kg / cm. 2 The fire-retardant particleboard is produced by a heat-pressing process that lasts for 7 minutes and 30 seconds (2-3.3-2 minutes).

[0057] The flame retardant composition for wood and wood-based materials, and the method for manufacturing flame-retardant wood and flame-retardant wood-based materials according to the present invention improve flame retardancy while reducing the burden on the environment. As a result, the inherent physical properties of wood and wood-based materials are improved, and the natural patterns and aesthetics of wood can be maintained. Therefore, the flame retardant composition can be applied to wooden houses, wooden furniture, wooden cultural properties, and various household items.

[0058] The present invention will be described in detail below with reference to examples. Those skilled in the art will clearly understand that the examples described below are merely illustrative examples for more specifically explaining the present invention, and that the present invention is not limited by these examples. [Example]

[0059] Flame-retardant board treatment A Radiata pine board (100 mm x 100 mm x 40 mm, longitudinal sealing) was placed in a pressure injector filled with a wood flame retardant composition, and subjected to pre-exhaust (0.08 MPa) at 43°C for 30 minutes and pressure of 20 kg / cm. 2 The flame retardant used was a flame retardant with a solid content of 20.8 wt% phenolic resin, 15.3 wt% boric acid, and 19.2 wt% sodium borate, for a total solid content of 34.5 wt% boric acid-sodium borate, meaning the solid content of the boric acid-sodium borate was 1.66 times higher than the solid content of the phenolic resin.

[0060] The boards impregnated through the above fireproofing treatment were then dry cured at 60°C for 24 hours and cured at 105°C for 24 hours to produce fire-retardant treated wood. The results of the fire resistance test of the fire-retardant treated boards using a cone calorimeter are as follows:

[0061] The weight gain (WPG: Weight Percent Gain) was 48.28%, the ignition time was 100 seconds, and the weight loss was 8.24%. Performance tests were conducted using a cone calorimeter in accordance with KS F ISO 5660-1, and the results showed that the flame retardant grade was met, as shown in Figure 6 ((a): Total Heat Release Rate (THR), (b): Heat Release Rate (HRR)).

[0062] Physical properties (flame retardant board material / untreated board material) are density 0.60 / 0.42g / cm 2The moisture content was 8.81 / 7.83%. Furthermore, while the weight gain of the flame-retardant-treated board was 48.28%, the weight loss in the leaching test (KS M 1701-2018) was 28.12±0.026%, confirming the effect of increasing the amount of flame retardant remaining in the sample and significantly increasing leaching resistance. Figure 2 shows photographs comparing untreated and flame-retardant-treated boards before and after the leaching test. After 10 leaching treatments, the untreated board (right side of 1) had severe cracks on the wood surface, while the flame-retardant-treated board (right side of 2) had a clean surface, just like before treatment, demonstrating extremely high dimensional stability. [Example]

[0063] Production of laminated lumber after fire-retardant treatment of radiata pine boards Radiata pine boards (100 mm x 100 mm x 40 mm, longitudinal sealing) were placed in a pressure injector filled with a wood flame retardant composition and heated to 14 kg / cm at 60°C. 2 The flame retardant used was a flame retardant with a phenolic resin solids content of 20.8 wt%, boric acid solids content of 15.3 wt%, and sodium borate solids content of 19.2 wt%, for a total solids content of 34.5 wt%. The boric acid-sodium borate solids content was 1.66 times higher than the phenolic resin solids content. The weight gain (WPG) of the treated radiata pine boards (10 mm thick) was 63.76%. The injected boards were dry-cured at 60°C for 24 hours and then cured at 105°C for 24 hours to produce flame-retardant treated wood. The flame-retardant treated boards were manufactured into laminated lumber by applying phenolic resin (application amount 200 g / m) from Company S to two boards. 2 , 150℃, 10kgf / cm 2 The heat pressing was carried out using a pressure of 1000kJ / 2000kcal (35 min.).

[0064] The results of the fire resistance test using a cone calorimeter on the fire-retardant treated radiata pine laminated timber are as follows:

[0065] The ignition time was no ignition, and the weight loss rate (600 seconds) was 7.16%. Performance tests were conducted using a cone calorimeter in accordance with KS F ISO 5660-1, and the results showed that the material met the quasi-nonflammable grade, as shown in Figure 7 ((a): Total Heat Release Rate (THR), (b): Heat Release Rate (HRR)).

[0066] The physical properties (fire-retardant laminated lumber / untreated laminated lumber) are density 0.60 / 0.42g / cm 2 The moisture content was 8.81 / 7.83%. [Example]

[0067] Production of plywood after veneer flame retardant treatment The larch veneer (2.4 mm thick) was placed in a pressure injector filled with a wood flame retardant and heated to 14 kg / cm at 60°C. 2 The liquid flame retardant used had a composition of 20.8 wt% phenolic resin solids, 15.3 wt% boric acid solids, and 19.22 wt% sodium borate solids, for a total solids content of 34.5 wt% boric acid-sodium borate. The veneer impregnated through the fireproofing treatment was then dry cured at 60°C for 24 hours and cured at 105°C for 24 hours. Five plywood sheets (with a phenolic resin coating of 200 g / m) were made using the flame-retardant treated veneer. 2 , 150℃, 10kgf / cm 2 The results of the fire resistance and physical property tests using a cone calorimeter for the plywood made from the flame-retardant treated veneer are as follows:

[0068] The weight gain rate (WPG) was 30.09%, the ignition time was 99 seconds, and the weight loss rate (300 seconds) was 13.28%. Performance tests were conducted using a cone calorimeter in accordance with KS F ISO 5660-1, and the results showed that the flame retardant grade was met, as shown in Figure 8 ((a): Total heat release rate (THR), (b): Heat release rate (HRR)).

[0069] Physical properties (fire-retardant plywood / untreated plywood) are density 0.75±0.11 / 0.67±0.04g / cm 2 , moisture content 9.05±0.04 / 9.53±0.07%, tensile shear adhesive strength 0.89±0.12 / 1.19±0.26N / mm 2 and the water-resistant tensile strength is 0.82 / 0.84N / mm 2 Therefore, the density of the plywood increases with the flame retardant treatment, and there is no decrease in adhesive strength due to the flame retardant treatment, but in contrast, the treated material consisting only of a mixture of boric acid and sodium borate immediately peeled off at the adhesive site when cut, showing a significant difference from the flame retardant consisting of the disclosed compound of phenolic resin, boric acid, and sodium borate. [Example]

[0070] Flame retardant treatment of pre-made plywood Pre-made plywood (larch: 2.4 mm thick, 13 veneer plywood, dimensions (T) 30 × (W) 100 × (L) 300 mm, Radiata pine: 2.4 mm thick, 9 veneer plywood, dimensions (T) 21 × (W) 100 × (L) 300 mm) and flame retardant were placed in a pressurizer and heated to 14 kg / cm at 60°C. 2 The flame retardant used was a water-resistant flame retardant for wood, with a ratio of boric acid-sodium borate solids to phenolic resin solids of 1.66, i.e., the phenolic resin solids were 20.8 wt%, boric acid solids were 15.3 wt%, and sodium borate solids were 19.2 wt%, for a total boric acid-sodium borate solids of 34.5 wt%.

[0071] The board material impregnated through the fireproofing treatment was dry cured at 60°C for 24 hours and then cured at 105°C for 24 hours to produce fire-retardant treated wood.

[0072] The results of the fire resistance test using a cone calorimeter on the flame retardant treated Radiata pine plywood are as follows:

[0073] The ignition time was 140 seconds, and the weight loss rate (at 300 seconds) was 9.2%. Performance tests were conducted using a cone calorimeter in accordance with KS F ISO 5660-1, and the flame retardant grade was met, as shown in Figure 9 ((a): Total Heat Release Rate (THR), (b): Heat Release Rate (HRR)).

[0074] The physical properties (fire-retardant plywood / untreated plywood) are density 0.69 / 0.51g / cm 2 The moisture content was 7.70 / 7.44%. The weight gain (WPG) due to the fire retardant was 36.3%.

[0075] The results of the fire resistance test of the flame-retardant treated larch plywood using a cone calorimeter were as follows:

[0076] The ignition time was 187 seconds, and the weight loss rate (300 seconds) was 7.94%. Performance tests were conducted using a cone calorimeter in accordance with KS F ISO 5660-1, and the flame retardant grade was met, as shown in Figure 10 ((a): Total Heat Release Rate (THR), (b): Heat Release Rate (HRR)).

[0077] Physical properties (fire-retardant plywood / untreated plywood) are density 0.75±0.03 / 0.67±0.08g / cm 2 , moisture content 9.05±0.12 / 9.53±0.10%, tensile shear adhesive strength 1.98±0.37 / 2.09N / mm 2 The water resistant tensile strength is 0.82±0.078 / 0.84N / mm 2 Therefore, it can be seen that the density of the plywood increases with the flame retardant treatment, and that the adhesive strength does not decrease due to the flame retardant treatment. Furthermore, while the weight gain rate of the flame retardant-treated plywood due to the fireproofing agent treatment was 22.46±0.49%, the weight loss rate in the leaching test was only 7.2±0.27%, which shows that a large amount of flame retardant remains in the sample, resulting in extremely high resistance to leaching. [Example]

[0078] Manufacture of fire-retardant particle board The flame retardant used was a phenolic resin with a solid content of 20.8 wt%, boric acid with a solid content of 15.3 wt%, and sodium borate with a solid content of 19.2 wt%, for a total solid content of 34.5 wt%. This boric acid-sodium borate solid content was 1.66 times higher than the solid content of the phenolic resin. These flame retardants were mixed and applied in an applicator at 30% and 50% ratios based on the total dry particle weight. The mixture was then dried at 60°C for 24 hours and then cured at 150°C for 30 minutes. Melamine resin (53% solid content) was added to the particles at 10% based on the total dry weight of the particles, and a 20% NH4Cl solution (3% based on the weight of the resin) was added as a curing agent. The mixture was then molded into a mat and then heated at 175°C under pressures of 45-30-20 kg / cm. 2 The flame-retardant particleboard was manufactured by hot pressing under the conditions of a pressure of 1000 kJ / cm2 for 7 minutes 30 seconds (2-3.3-2 minutes). The results of the fire resistance test of the 30% flame-retardant particleboard using a cone calorimeter are as follows:

[0079] The ignition time was 42 seconds, and the weight loss rate (300 seconds) was 13.42%. Performance tests were conducted using a cone calorimeter in accordance with KS F ISO 5660-1, and the flame retardant grade was met, as shown in Figure 11 ((a): Total Heat Release Rate (THR), (b): Heat Release Rate (HRR)).

[0080] The results of the fire resistance test using a cone calorimeter for particleboard that was 50% fire retardant treated were as follows:

[0081] The ignition time was no ignition at all, and the weight loss rate (600 seconds) was 24.39%. Performance tests were conducted using a cone calorimeter in accordance with KS F ISO 5660-1, and the results showed that the quasi-noncombustible flade met the criteria, as shown in Figure 12 ((a): Total Heat Release Rate (THR), (b): Heat Release Rate (HRR)).

[0082] The physical properties (30wt% fire-retardant particle board / 50wt% fire-retardant particle board / untreated particle board) are density 0.92±0.05 / 1.01±0.07 / 0.81±0.06g / cm 2 , moisture content 6.733±0.19 / 7.267±0.64 / 6.81±0.42%, bending strength 21.894±1.89 / 23.605±1.76 / 22.783±0.70N / mm 2 , and the wet bending strength was 7.01±0.67 / 7.56±0.81 / 6.53±0.97N / mm 2 , peel strength is 0.81±0.05 / 0.904±0.07 / 0.97±0.09N / mm 2 It was.

[0083] Yalinkilik, MK et al. (1998) have reported that particleboard treated with boric acid and borax (4.7% treatment) had a 42.4% decrease in internal adhesive strength compared to untreated particleboard. However, the peel strength of particleboard treated with only boric acid and sodium borate solution (40% of the particle weight) as a comparison value in the example was 0.27 N / mm 2 and 0.97N / mm for untreated particle board. 2In contrast, when treated with the flame retardant consisting of phenol, boric acid, and sodium borate of the present disclosure, there was no statistical difference compared to the untreated specimen, even when treated at 30% or 50% of the total dry particle weight (F = 1.826). Furthermore, it was found that the wet bending strength actually increased as the treatment amount increased compared to the untreated specimen, and the wet bending strength was higher than that of the untreated specimen. Furthermore, the results of a leaching treatment test (KS M 1701-2018) of particleboard treated with the flame retardant consisting of the phenol resin, boric acid, and sodium borate compound of the present disclosure showed that the weight loss rate (WPL) of (30% flame-retardant particleboard / 50% flame-retardant particleboard) was 1.0%. The weight gains were 10.16±0.03% and 15.26±0.05%, respectively. This indicates a higher residual flame retardant in the particleboard, demonstrating high leaching resistance. Furthermore, the leaching test results for the untreated particleboard (shown on the right in Figure 3, 1.) showed a significant thickness expansion with a thickness swelling of 48±0.8%, whereas the particleboard treated with 50% flame retardancy (shown on the right in Figure 3, 2.) showed a thickness swelling of 12±0.3%, demonstrating very high dimensional stability. Therefore, treatment with the flame retardant compound of phenolic resin, boric acid, and sodium borate disclosed herein confines or seals the boric acid and sodium borate within the wood, thereby compensating for the reduced adhesive strength and water resistance inherent to boron, thereby contributing to dimensional stability and compensating for the reduced internal bond strength inherent to treatment with a flame retardant compound consisting of boric acid and sodium borate alone. [Example]

[0084] Flame retardant treatment of larch veneer with a flame retardant consisting of a mixture of phenol-resorcinol resin, boric acid, and sodium borate (PRB: Phenol-Resorcinol resin·Boron complex) 94g (1 mole) of phenol, 171.4g (2.0 moles) of 35% formalin, and 15g of water were placed in a resin reactor, adjusted to pH 11 with NaOH, and reacted at 70°C for 1 hour to produce a liquid resol-type phenolic resin (solid content 51.7%, pH 11.0, viscosity 24.3 cps). A boric acid-sodium borate solution containing 25.53wt% boric acid and 31.91wt% sodium borate (borax) was added and heated to 90-100°C to produce a boric acid-sodium borate mixture that was highly soluble in water until it became transparent. The temperature was maintained at 60°C, and the mixture was reacted with the phenolic resin for 2 hours to produce a phenolic resin with a solid content of 23.4wt%, a boric acid solid content of 14.03wt%, and a sodium borate (sodium borate). The solids content of the phenolic resin and the resorcinol resin was 21.3 wt% and 9.1 wt%, respectively, for a total resin solids content of 30.4 wt%, and the solids content of the boric acid-sodium borate was 12.8 wt% and 15.9 wt%. The total solids content of the boric acid-sodium borate was 28.7 wt%. Subsequently, while maintaining the temperature at 60°C, 10 g of resorcinol was added and dissolved by stirring for 15 minutes. The reaction was then continued for an additional 2 hours to produce a water-resistant phenolic-resorcinol-boric acid-sodium borate flame retardant for wood (pH 7.35, viscosity 36.9 cps) with a phenolic resin solids content of 21.3 wt% and a resorcinol resin solids content of 9.1 wt%, for a total resin solids content of 30.4 wt%, a boric acid solids content of 12.8 wt% and a sodium borate solids content of 15.9 wt%, for a total boric acid-sodium borate solids content of 28.7%.

[0085] A larch veneer (2.4 mm thick) was placed in a pressure injector filled with the above-mentioned wood flame retardant and subjected to a temperature of 40°C and 25 kg / cm 2 The veneer impregnated through the fireproofing treatment was then dry cured at 60°C for 24 hours and then cured at 105°C for 24 hours. Five plywood sheets (with a phenolic resin coating of 200 g / m) were prepared using this fireproofing treatment. 2 , 150℃, 10kgf / cm 2The fire resistance and physical properties of the plywood made from the flame-retardant treated veneer were tested using a cone calorimeter, and the results are as follows:

[0086] The ignition time was 131 seconds, and the weight loss rate (300 seconds) was 14.28%. Performance tests were conducted using a cone calorimeter in accordance with KS FISO 5660-1, and the flame retardant grade was met as shown in Figure 13 ((a): Total Heat Release Rate (THR), (b): Heat Release Rate (HRR)).

[0087] The physical properties (fire-retardant treated plywood / untreated plywood) are density 0.70±0.05 / 0.67±0.04g / cm 2 The moisture content was 7.70±0.06 / 9.53±0.07%. The weight gain (WPG) due to the fire retardant was 33.18±0.01%. The tensile shear adhesive strength was 0.99±0.08 / 1.19±0.26N / mm 2 It was. [Example]

[0088] Flame retardant treatment of larch veneer using a flame retardant consisting of resorcinol-phenol resin·boron complex (RPB) 94g (1 mole) of phenol, 171.4g (2.0 moles) of 35% formalin, and 15g of water were placed in a resin reactor, adjusted to pH 11 with NaOH, and reacted at 70°C for 1 hour to produce a liquid resol-type phenolic resin (solid content 51.7%, pH 11.0, viscosity 24.3 cps). A boric acid-sodium borate solution containing 25.53wt% boric acid and 31.91wt% sodium borate (borax) was added and heated to 90-100°C to produce a boric acid-sodium borate mixture that was highly soluble in water until it became transparent. The mixture was then reacted with the phenolic resin produced above while maintaining the temperature at 60°C to produce a phenolic resin with a solid content of 23.4wt%, a boric acid solid content of 14.03wt%, and a sodium borate solid content of 24.3cps. The mixture was reacted for 2 hours until the solids content of the boric acid-sodium borate was 17.54 wt% and the total solids content of the boric acid-sodium borate was 31.57%. Subsequently, while maintaining the temperature at 60°C, 30 g of resorcinol was added, and the mixture was stirred for 15 minutes to dissolve. The reaction was then continued for another 2 hours to produce a waterproof flame-retardant adhesive for wood. The composition of the resorcinol-phenol co-condensation resin used as the flame-retardant adhesive thus produced was as follows: the solids content of the phenolic resin was 18.6 wt% and the solids content of the resorcinol resin was 28.6 wt%, resulting in a total solids content of 47.2 wt% of the adhesive; the solids content of the boric acid (9.1 wt%) and the solids content of the sodium borate (11.4 wt%), resulting in a total solids content of 20.5 wt% of the boric acid-sodium borate; and the remainder was 32.3 wt% distilled water. This flame-retardant adhesive hardens to form a fire-resistant layer, imparting flame retardancy, and the flame-retardant components in the adhesive diffuse into adjacent wood materials, i.e., veneers and boards, imparting flame retardancy. The pH of the flame-retardant adhesive made from a resorcinol-phenol co-condensation resin-boric acid-sodium borate complex (RPB) produced in this way was 7.62, and the viscosity was 48.3 cps. A flame-retardant adhesive prepared in a weight ratio of 100 parts flame-retardant adhesive, 15 parts wheat flour, and 30 parts hardener was applied to a 2.4 mm-thick radiata pine veneer board at a coating rate of 200 g / m. 2Five sheets of plywood were produced by applying the coating, and the heat and pressure conditions for the plywood were 10 kgf / cm 2 The plywood was then coated with a flame-retardant adhesive consisting of a resorcinol-phenol co-condensation resin, boric acid, and sodium borate complex (RPB) at a rate of 300 g / m². 2 The coating was applied at 25-30°C for 24 hours, and then cured at 150°C for 30 minutes.

[0089] The fire resistance of the manufactured plywood was tested using a cone calorimeter in accordance with KS F ISO 5660-1, and the results showed that it met the flame retardant grade, as shown in Figure 14 ((a): Total Heat Release Rate (THR), (b): Heat Release Rate (HRR)).

[0090] The physical properties of the manufactured plywood (fire-retardant plywood / untreated plywood) were density 0.65±0.01 / 0.43±0.03g / cm 2 The moisture content is 4.7±0.15 / 4.8±0.20%, and the density is increased by injecting flame retardant. The tensile shear adhesive strength in the non-waterproof state is 1.10±0.26 / 1.18±0.30N / mm 2 The results of the t-test (t=0.34) showed that there was no statistically significant difference in the non-waterproof tensile shear adhesive strength between the two groups.

[0091] Water-resistant tensile shear adhesive strength: 0.99±0.09 / 0.98±0.09N / mm 2 The results of the t-test (t=0.07) showed that there was no statistically significant difference in the water-resistant tensile shear adhesive strength of the two groups. Therefore, when flame-retardant plywood is manufactured using flame-retardant adhesives, good plywood is obtained without a decrease in adhesive strength due to the flame retardant. In addition, the results of tests using a cone calorimeter in accordance with KS F ISO 5660-1 show that the flame-retardant grade is met.

[0092] The flame-retardant treated wood and wood materials produced in Examples 1 to 7 were subjected to performance tests using a cone calorimeter in accordance with KS F ISO 5660-1, and all of them met the flame-retardant grade standard or higher, as shown in Figures 6 to 14. Here, the flame-retardant grade refers to a heat release rate of 200 kW / m2 in a 5-minute measurement at 50 kW of heat when measured with the cone calorimeter. 2 and total heat release is 8MJ / m or less 2 The semi-non-combustible grade is one that meets the conditions above, and the heat release rate is 200kw / m when measured for 10 minutes against 50kW of heat. 2 and total heat release is 8MJ / m or less 2 It satisfies the following conditions.

[0093] 4 shows the surface condition of untreated wood and wood treated with a flame retardant according to an embodiment of the present invention, as a result of an ignition test using a cone calorimeter. The wood treated with a flame retardant according to an embodiment of the present invention has a charred layer formed on the surface due to high temperature, but the back surface is clean, and it can be seen that the thickness of the charred layer is significantly reduced compared to untreated board material.

[0094] In the present invention, as described above, the flame retardancy is doubled and the solid content of the high-concentration boric acid-sodium borate mixture is stably used. By using a phenolic resin as a carrier to contain this, a stable flame retardant is produced and the reduced adhesive strength and moisture vulnerability caused by the inorganic treatment of boric acid-sodium borate are improved. This produces an adhesive-friendly flame retardant agent consisting of a boric acid-sodium borate mixture and a stable phenolic resin compound. This allows the production of flame-retardant wood and wood-based materials that maintain the wood's natural pattern and clean surface, are resistant to water leaching, and are dimensionally stable. Therefore, it is expected that wood, which is often referred to as canned carbon dioxide, can be used in buildings for a long period of time, greatly contributing to the prevention of global warming and carbon neutrality.

[0095] As described above, in this specification and drawings, specific terms are used to describe specific embodiments of the present invention, but these terms are used in a general sense to aid in understanding the present invention and are not intended to limit the scope of the present invention, and will be apparent to those skilled in the art to which the present invention pertains. [Industrial Applicability]

[0096] According to one embodiment of the present invention, wood with excellent flame retardancy can be provided. Therefore, the flame retardant wood according to one embodiment of the present invention is particularly suitable for various building materials such as architectural wall materials, ceiling materials, floor materials, bathroom wood, doors, as well as materials for furniture, bedding, interior decoration, etc.

Claims

1. S1) Preparing wood or wood-based material; S2) preparing a wood flame retardant comprising a phenolic resin and a boric acid-sodium borate mixture, and then adding resorcinol to the wood flame retardant to prepare a wood flame retardant composition; S3) injecting the wood flame retardant composition obtained in step S2) into the wood or wood-based material; and S4) drying and hardening the impregnated wood or wood-based material; A method for producing flame-retardant wood or a flame-retardant wood material, comprising:

2. A method for producing flame-retardant wood or a flame-retardant wood material as described in claim 1, characterized in that the flame retardant composition for wood contains, relative to its weight, within the ranges of 16 to 36 wt% of phenolic resin, 8 to 18 wt% of boric acid, and 10 to 22 wt% of sodium borate, and the total amount of the boric acid and the sodium borate is within the range of 18 to 40 wt%.

3. A method for producing flame-retardant wood or flame-retardant wood material as described in claim 1, characterized in that the resorcinol is a liquid resol type that can be used to produce a co-condensation resin with phenol.

4. A method for producing flame-retardant wood or a flame-retardant wood material as described in claim 3, characterized in that the wood flame retardant composition contains resorcinol in the range of 10 to 40 wt% based on its weight.

5. A method for producing flame-retardant wood or a flame-retardant wood material as described in claim 4, characterized in that the flame retardant composition for wood contains, relative to its weight, within the ranges of 23 to 33 wt% of resorcinol, 15 to 21 wt% of phenolic resin, 6.8 to 10.9 wt% of boric acid, and 8.5 to 13.7 wt% of sodium borate, and the total amount of the resorcinol and the phenolic resin is within the range of 38 to 54 wt%, and the total amount of the boric acid and the sodium borate is within the range of 15.3 to 24.6 wt%.

6. The step S2) S2-1) Mixing boric acid and sodium borate in a solvent to prepare a boric acid-sodium borate mixture; and S2-2) mixing and reacting the boric acid-sodium borate mixture with a phenolic resin; A method for producing the flame-retardant wood or wood-based material according to claim 1, comprising:

7. The method for producing a flame-retardant wood or wood-based material according to claim 1, further comprising the step of: S5) subjecting the wood or wood-based material to a heat-pressing process to produce a final wood-based material.

8. 2. The method for producing a flame-retardant wood or a flame-retardant wood material according to claim 1, wherein the wood or wood material is at least one selected from the group consisting of veneers, boards, particles, strands, and fibers obtained from logs, and plywood, laminated veneer lumber (LVL), glued lumber, cross-laminated timber (CLT) for structures, particle board, strand board, and fiberboard made from these.

9. 7. The method for producing a flame-retardant wood or wood-based material according to claim 6, further comprising a step of producing a phenolic resin before step S2-2), wherein the step of producing the phenolic resin comprises adding phenol, formalin, and water to a resin reactor, adjusting the pH to 10.7 to 11.0 with sodium hydroxide (NaOH), and reacting the water to obtain a liquid resol-type phenolic resin.

10. 8. The method for producing a flame-retardant wood or woody material according to claim 7, wherein in step S2-1), boric acid and sodium borate are added to water and heated to 90-100°C to produce a boric acid-sodium borate mixture that dissolves well in water until it becomes transparent; and then in step S2-2), the phenolic resin is mixed and reacted so that the proportions of the produced phenolic resin are 16-36 wt% phenolic resin, 8-18 wt% boric acid, and 10-22 wt% sodium borate, and the total amount of the boric acid and sodium borate is 18-40 wt%.

11. 2. The method for producing a flame-retardant wood or a flame-retardant wood material according to claim 1, wherein the flame retardant composition for wood contains, based on its weight, 23 to 33 wt% of resorcinol, 15 to 21 wt% of phenolic resin, 6.8 to 10.9 wt% of boric acid, and 8.5 to 13.7 wt% of sodium borate, and the total amount of the resorcinol and the phenolic resin is 38 to 54 wt%, and the total amount of the boric acid and the sodium borate is 15.3 to 24.6 wt%.

12. 2. The method for producing a flame-retardant wood or wood material according to claim 1, wherein in step S3), the injection treatment is performed by diffusion and penetration at normal pressure.

13. In the step S3), the injection treatment method is such that the main pressure is 10 to 25 kg / cm ２ 2. The method for producing a flame-retardant wood or wood material according to claim 1, characterized in that the method is a pressurized / depressurized method in which the treatment is carried out at a temperature of 0.5 to 1.0°C for 30 to 120 minutes.

14. 14. The method for producing a flame-retardant wood or wood material according to claim 13, wherein in step S3), pre-exhaust is performed for 30 minutes and post-exhaust is performed for 10 to 30 minutes before and after the main pressurization.

15. The method for producing a flame-retardant wood or wood material according to claim 1, wherein step S4) includes a step of stabilizing the injected wood or wood material at room temperature, drying the wood or wood material at 50 to 70°C for a certain period of time, and then curing the resin at 100 to 150°C.

16. 9. The method for producing fire-retardant wood or fire-retardant wood material according to claim 8, wherein in step S5, the veneer is produced as plywood or laminated veneer lumber (LVL), the board is produced as laminated lumber or cross-laminated timber (CLT), the particles are produced as particle board, the strands are produced as strand board, and the fibers are produced as fiber board.

17. A method for producing a flame retardant composition for wood and wood-based materials, comprising boric acid, sodium borate, and a water-soluble phenolic resin, the method comprising: mixing and reacting a boric acid-sodium borate mixture with a phenolic resin; The phenolic resin is a liquid resol-type phenolic resin prepared by adding phenol, formalin, and water to a resin reactor and adjusting the pH to 10.7 to 11.0 with sodium hydroxide (NaOH). The boric acid-sodium borate mixture is a solution containing boric acid and sodium borate, and is characterized in that it is a transparent boric acid-sodium borate mixture that is highly soluble in water and is produced by adding 25.53 wt % of boric acid and 31.91 wt % of sodium borate to water and heating the mixture to 90°C to 100°C. A method for producing a flame retardant composition for wood and wood-based materials.

18. 18. The method for producing a flame retardant composition for wood and wood-based materials according to claim 17, wherein the phenolic resin is a liquid resol-type phenolic resin produced by adding the phenol and the formalin to the resin reactor in a molar ratio of phenol:formalin=1:1.63 to 2.4, adjusting the pH to 10.7 to 11.0 with sodium hydroxide (NaOH), and reacting at 70 to 80°C.

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