Flame retardant, composite, method for manufacturing a flame retardant, method for manufacturing a composite

Abstract

The present invention provides a flame retardant, a composite, a method for producing the flame retardant, and a method for producing the composite, all of which offer excellent environmental safety and flame retardancy. [Solution] A flame retardant comprising at least one of a dimer of silatran glycolate represented by the following chemical formula (1) and a tetramer of silatran glycolate represented by the following chemical formula (2). [C1] TIFF2026067829000015.tif64170

Description

[Technical Field]

[0001] The present invention relates to a flame retardant, a composite, a method for producing a flame retardant, and a method for producing a composite. [Background technology]

[0002] For wood flame retardants, less toxic, non-halogen types are used. Among non-halogen flame retardants, phosphorus-based flame retardants and synergistic phosphorus-nitrogen-based flame retardants are easily soluble in water and can be impregnated into wood in large quantities. Therefore, these flame retardants are widely used because they easily provide flame retardant properties.

[0003] Phosphorus-based flame retardants and synergistic phosphorus- and nitrogen-based flame retardants are the mainstream flame retardants used in commercially available flame-retardant treated wood (see, for example, Patent Document 1). However, when this flame-retardant treated wood gets wet or is placed in a humid environment, the flame retardant deliquesces or leaches out. This leads to problems such as reduced durability due to impaired fire resistance and efflorescence, where the deliquesced flame retardant precipitates on the surface and dries, resulting in a white stain.

[0004] Besides phosphorus-based flame retardants and synergistic phosphorus-nitrogen-based flame retardants, other known non-halogen flame retardants include boron-based flame retardants (see, for example, Patent Document 2) and silicon-based flame retardants (see, for example, Patent Document 3). Boron-based flame retardants are poorly soluble in water and difficult to impregnate into wood, resulting in inferior flame retardancy and the problem of efflorescence, where crystals of the flame retardant component form on the surface. Silicon-based flame retardants provide high flame retardancy, but are not widely used due to their high cost. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2023-028750 [Patent Document 2] Japanese Patent Publication No. 2005-112700 [Patent Document 3] Japanese Patent Publication No. 2005-047140 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The present invention has been made in view of the above circumstances, and aims to provide a flame retardant, a composite, a method for producing the flame retardant, and a method for producing the composite, which are excellent in environmental safety and flame retardancy. [Means for solving the problem]

[0007] The present invention has the following aspects. [1] A flame retardant comprising at least one of a dimer of silatran glycolate represented by the following chemical formula (1) and a tetramer of silatran glycolate represented by the following chemical formula (2).

[0008] [ka]

[0009] [ka]

[0010] [2] A composite comprising wood and the flame retardant described in claim 1 impregnated into the wood.

[0011] [3] A method for producing a flame retardant, comprising the step of reacting silicon dioxide and triethanolamine in glycol to synthesize at least one of a dimer of silatran glycolate represented by the following chemical formula (1), a tetramer of silatran glycolate represented by the following chemical formula (2), and a monomer of silatran glycolate represented by the following chemical formula (3).

[0012] [ka]

[0013] [Chemical formula]

[0014] [Chemical formula]

[0015] [4] The method for producing a flame retardant according to [3], wherein the silicon oxide is a component contained mainly in silica gel or a component contained mainly in rice straw ash.

[0016] [5] The method for producing a flame retardant according to [3], wherein the glycol is ethylene glycol.

[0017] [6] A step of dissolving the flame retardant according to [1] in a solvent to prepare a solution containing the flame retardant, A step of impregnating the wood with the flame retardant by immersing the wood in the solution or applying the solution to the surface of the wood, A method for producing a composite, comprising a step of drying the wood impregnated with the solution. [Advantages of the Invention]

[0018] According to the present invention, it is possible to provide a flame retardant, a composite, a method for producing a flame retardant, and a method for producing a composite, which are excellent in environmental safety and flame retardancy. [Brief Description of the Drawings]

[0019] [Figure 1] It is a diagram showing the analysis result of electrospray ionization mass spectrometry (ESI-MS) of the product obtained in the synthesis example. [Figure 2] In Example 1, it is a diagram showing the results of thermogravimetric differential thermal analysis of the composite and untreated wood. [Figure 3] In Example 2, it is a diagram showing the results of a cooling curve measurement test (CCM Test) of the composite and untreated wood. [Figure 4]This figure shows the results of the heat generation tests for the composite and untreated wood in Example 3. [Figure 5] The image in Example 4 shows the surface condition of Sample 1 and Sample 2 before impregnation with the flame retardant, with Sample 1 on the left and Sample 2 on the right. [Figure 6] The image in Example 4 shows the surface condition of Sample 1 and Sample 2 after impregnation with a flame retardant and drying, with Sample 1 on the left and Sample 2 on the right. [Figure 7] In Example 4, the photograph shows sample 2 cut along the dashed line shown in Figure 6, with the left side showing the surface state of sample 2 and the right side showing the cross-sectional state of sample 2. [Modes for carrying out the invention]

[0020] Embodiments of the flame retardant, composite, method for producing the flame retardant, and method for producing the composite of the present invention will be described. This embodiment is provided to give a better understanding of the spirit of the invention and does not limit the present invention unless otherwise specified.

[0021] [Flame retardant] A flame retardant according to one embodiment of the present invention comprises at least one of a dimer of silatran glycolate represented by the following chemical formula (1) and a tetramer of silatran glycolate represented by the following chemical formula (2).

[0022] [ka]

[0023] [ka]

[0024] The dimers and tetramers of silatlanglycolate have a structure formed by the dehydration condensation of silatlanglycolate monomers, represented by the following chemical formula (3).

[0025] [ka]

[0026] The flame retardant of this embodiment may contain only a dimer of silatranglycolate, only a tetramer of silatranglycolate, or both a dimer and a tetramer of silatranglycolate.

[0027] When the flame retardant of this embodiment contains a dimer of silatran glycolate and a tetramer of silatran glycolate, the ratio of the tetramer to the dimer (tetramer / dimer) is preferably 0.001 or more and 1000 or less by mass, and more preferably 0.01 or more and 100 or less. If the ratio is below the lower limit, the viscosity of the solution becomes high and it becomes difficult to form a coating film. If the ratio exceeds the upper limit, the viscosity of the solution becomes low and it becomes difficult to form a coating film.

[0028] The flame retardant of this embodiment contains at least one of a silatran glycolate dimer and a silatran glycolate tetramer, thus enabling the realization of an inexpensive flame retardant with excellent environmental safety and flame retardancy. Furthermore, the flame retardant of this embodiment does not suffer from deliquescence, leaching, or efflorescence, which are problems with conventional wood flame retardants. Moreover, the flame retardant of this embodiment can achieve flame retardant effects with a smaller amount compared to conventional wood flame retardants.

[0029] [Method for manufacturing flame retardants] A method for producing a flame retardant according to one embodiment of the present invention includes a step of reacting silicon dioxide and triethanolamine in glycol to synthesize at least one of the dimer of silatranglycolate represented by the above chemical formula (1), a tetramer of silatranglycolate represented by the above chemical formula (2), and a monomer of silatranglycolate represented by the above chemical formula (3).

[0030] The silicon dioxide used in the flame retardant manufacturing method of this embodiment is a component mainly contained in silica gel or a component mainly contained in rice straw ash. In the flame retardant manufacturing method of this embodiment, silica gel or rice straw ash can be used as is. The silicon dioxide content in silica gel is 10% by mass or more and 90% by mass or less. The silicon dioxide content in rice straw ash is 10% by mass or more and 90% by mass or less.

[0031] As the glycol, ethylene glycol, propylene glycol, butylene glycol, etc., can be used. Among these, ethylene glycol is preferred from the viewpoint of being able to achieve a temperature suitable for synthesis, having a suitable boiling point so that it can be removed by distillation under reduced pressure after the reaction, and as a result being able to increase the concentration of the silicon component in the flame retardant solution.

[0032] (Method for producing dimers and tetramers of silatranglycolate) Silica gel is used as silicon dioxide to produce silatranglycolate dimers and silatranglycolate tetramers. When silica gel is used as silicon dioxide, the ratio of triethanolamine to silica gel (triethanolamine / silica gel) is preferably 1 to 10 in molar ratio, and more preferably 1 to 5. If the ratio is below the lower limit, silicon dioxide will be in excess in stoichiometric ratio, reducing the amount of the desired product produced. If the ratio exceeds the upper limit, unreacted triethanolamine will be mixed in, reducing the concentration of the desired product.

[0033] When silica gel is used as silicon dioxide, the ratio of silica gel to glycol (silica gel / glycol) is preferably 0.1 or more and 1 or less in terms of molar ratio. If the ratio is below the lower limit, unreacted glycol will be mixed in, reducing the concentration of the target product. If the ratio exceeds the upper limit, silicon dioxide will be in excess in terms of stoichiometric ratio, reducing the amount of the target product produced.

[0034] When silica gel is used as silicon dioxide, the ratio of triethanolamine to glycol (triethanolamine / glycol) is preferably 0.1 or more and 1 or less in molar ratio. If the ratio is below the lower limit, glycol will be in excess in stoichiometric ratio, and the amount of the target product produced will decrease. If the ratio exceeds the upper limit, triethanolamine will be in excess in stoichiometric ratio, and the amount of the target product produced will decrease.

[0035] When silica gel is used as silicon dioxide, the temperature at which silicon dioxide and triethanolamine react in glycol is preferably 50°C to 250°C, and more preferably 100°C to 200°C. If the temperature is below the lower limit, the reaction to produce the target compound will not proceed. If the temperature exceeds the upper limit, the target compound may decompose due to overheating.

[0036] When silica gel is used as silicon dioxide, the reaction time between silicon dioxide and triethanolamine in glycol is preferably 1 hour to 96 hours, and more preferably 8 hours to 24 hours. If the above time is less than the lower limit, the reaction will not proceed sufficiently and the amount of product produced will decrease. If the above time exceeds the upper limit, a significant increase in the amount of product produced cannot be expected, resulting in the consumption of excess energy.

[0037] The product obtained by this manufacturing method is a mixture of silatlanglycolate dimers and silatlanglycolate tetramers. The ratio of the tetramer to the dimer in this mixture (tetramer / dimer) is 0.01 or more and 100 or less by mass.

[0038] (Method for producing silatran glycolate monomers) To produce the monomer of silatran glycolate, rice straw ash is used as silicon dioxide. When using rice straw ash as silicon dioxide, the ratio of triethanolamine to rice straw ash (triethanolamine / rice straw ash) is preferably 1 to 10 in molar terms, and more preferably 1 to 5. If the ratio is below the lower limit, silicon dioxide will be in excess in stoichiometric terms, reducing the amount of the desired product produced. If the ratio exceeds the upper limit, unreacted triethanolamine will be mixed in, reducing the concentration of the desired product.

[0039] When using rice straw ash as silicon dioxide, the ratio of rice straw ash to glycol (rice straw ash / glycol) is preferably 0.1 or more and 1 or less in molar terms, and more preferably 0.2 or more and 1 or less. If the ratio is below the lower limit, unreacted glycol will be mixed in, reducing the concentration of the target product. If the ratio exceeds the upper limit, silicon dioxide will be in excess in stoichiometric terms, reducing the amount of the target product produced.

[0040] When using rice straw ash as silicon dioxide, the ratio of triethanolamine to glycol (triethanolamine / glycol) is preferably 0.1 or more and 1 or less in molar ratio. If the ratio is below the lower limit, glycol will be in excess in stoichiometric ratio, and the amount of the desired product produced will decrease. If the ratio exceeds the upper limit, triethanolamine will be in excess in stoichiometric ratio, and the amount of the desired product produced will decrease.

[0041] When using rice straw ash as silicon dioxide, the temperature at which silicon dioxide and triethanolamine react in glycol is preferably 50°C to 250°C, and more preferably 100°C to 200°C. If the temperature is below the lower limit, the reaction to produce the target compound will not proceed. If the temperature exceeds the upper limit, the target compound may decompose due to overheating.

[0042] When using rice straw ash as silicon dioxide, the reaction time between silicon dioxide and triethanolamine in glycol is preferably between 1 hour and 96 hours, and more preferably between 8 hours and 24 hours. If the above time is less than the lower limit, the reaction will not proceed sufficiently and the amount of product produced will decrease. If the above time exceeds the upper limit, a significant increase in the amount of product produced cannot be expected, resulting in the consumption of excess energy.

[0043] According to the method for producing the flame retardant of this embodiment, the flame retardant of the above-described embodiment can be obtained.

[0044] [complex] A composite according to one embodiment of the present invention comprises wood and a flame retardant impregnated into the wood.

[0045] Examples of wood include cedar and cypress.

[0046] Examples of flame retardants include the flame retardants described in the above-described embodiments.

[0047] The amount of flame retardant impregnated into the wood (content), in other words, the content of the flame retardant relative to the total mass (100% by mass) of the composite in this embodiment, is preferably 0.01% by mass or more and 300% by mass or less, more preferably 0.1% by mass or more and 100% by mass or less, and even more preferably 1% by mass or more and 50% by mass or less. If the content is below the lower limit, the effect of the flame retardant is low. If the content exceeds the upper limit, it is not possible to form a flame retardant coating.

[0048] The composite of this embodiment may contain a dye in addition to the flame retardant of the embodiment described above. Examples of dyes include methylene blue and Sudan III.

[0049] In the composite of this embodiment, the flame retardant may be present on the surface of the wood or inside the wood.

[0050] The composite of this embodiment comprises wood and the flame retardant of the above embodiment impregnated into the wood, thus enabling the realization of an inexpensive composite with excellent environmental safety and flame retardancy. Furthermore, the composite of this embodiment does not suffer from deliquescence, leaching, and efflorescence of the flame retardant, which are problems with flame-retardant treated wood using conventional wood flame retardants.

[0051] [Method for producing the composite] A method for producing a composite according to one embodiment of the present invention comprises the steps of: preparing a solution containing the flame retardant by dissolving the flame retardant of the above embodiment in a solvent (hereinafter referred to as the "first step"); impregnating the wood with the flame retardant by immersing the wood in the solution or applying the solution to the surface of the wood (hereinafter referred to as the "second step"); and drying the wood impregnated with the solution (hereinafter referred to as the "third step").

[0052] "First step" In the first step, the flame retardant according to the above embodiment is dissolved in a solvent to prepare a solution containing the flame retardant.

[0053] The solvent is not particularly limited as long as it can dissolve the flame retardant and penetrate into the wood, but for example, water, methanol, ethanol, ethylene glycol, etc. can be used.

[0054] The amount of flame retardant relative to the total mass (100% by mass) of the solution is preferably 1% by mass or more and 100% by mass or less, and more preferably 5% by mass or more and 20% by mass or less. If the amount is below the lower limit, the concentration of the flame retardant is low and the flame retardant effect will not be exhibited.

[0055] To observe how the flame retardant impregnates the wood, it is preferable to use an aqueous solution of methylene blue instead of the flame retardant. By using an aqueous solution of methylene blue, the impregnation process into the wood can be observed visually, and as a result, it is possible to estimate how deeply the flame retardant penetrates the wood.

[0056] The amount of methylene blue in the aqueous solution is preferably 0.1% by mass or more and 1% by mass or less, relative to the total mass (100% by mass). If the amount is below the lower limit, it is difficult to visually observe the impregnation process. If the amount exceeds the upper limit, the viscosity of the methylene blue solution increases, making impregnation difficult.

[0057] "The second step" In the second step, the wood is either immersed in the solution prepared in the first step, or the solution prepared in the first step is applied to the surface of the wood to impregnate it with the flame retardant. Methods for impregnating wood with a flame retardant solution include immersing the wood in a flame retardant solution at room temperature and atmospheric pressure, injecting the flame retardant solution into the wood at high temperature and high vacuum, immersing the wood in a flame retardant solution at room temperature and reduced pressure to impregnate the wood with the flame retardant solution under reduced pressure, and then pressurizing the wood with the flame retardant solution at room temperature and high pressure, and applying the flame retardant solution to the surface of the wood. For example, methods for applying the flame retardant solution can include brush application, roller application, spray application, dripping, and immersion.

[0058] "The third step" In the third step, the wood impregnated with the solution is dried. The preferred method for drying wood impregnated with the solution is to heat it in an electric dryer.

[0059] According to the method for manufacturing the composite of this embodiment, the composite of the above-described embodiment can be obtained. [Examples]

[0060] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0061] [Example of combination] 6.00 g of silica gel (product name: Wacogel C-200, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) (0.1 mol in terms of silicon dioxide) and 11.19 g of triethanolamine (0.075 mol) were added to 250 mL of ethylene glycol. The ethylene glycol containing silica gel and triethanolamine was stirred to allow the silicon dioxide in the silica gel to react with the triethanolamine. The reaction temperature was 175°C and the reaction time was 18 hours. The solution was then allowed to cool to room temperature, the supernatant was extracted, concentrated under reduced pressure, washed three times with acetonitrile, and then dried. The yield of the product was 52%. Figure 1 shows the results of electrospray ionization mass spectrometry (ESI-MS) analysis of the product. From the results shown in Figure 1, it was found that the obtained product contained both silatran glycolate dimers and silatran glycolate tetramers. The ratio of tetramers to dimers (tetramer / dimer) was approximately 0.5 by mass. Products 1 The results of the 1H NMR analysis are shown. Dimers of silatlanglycolate: 1 H NMR(399.00MHz, D2O / ppm): δ2.89(t,6H,J=6.0Hz,NCH2CH2),3.67(m,1H,OCH2CH2O),3.81(t,1H,J=5.4Hz,OCH2CH2O),3.87(t,7H,J=6.0Hz,NCH2CH2) tetramer of silatlan glycolate: 1 H NMR(399.00MHz,D2O / ppm):δ2.82(t,3H,J=5.4Hz,NCH2CH2),3.67(m,1H,OCH2CH2O),3.81(t,3H,J=5.4Hz,NCH2CH2)

[0062] [Example 1] A 2mm x 2mm x 2mm piece of wood (cedar) was immersed in an aqueous solution of the product obtained in the synthesis example, with a concentration of 0.2 mol / L, at room temperature (25°C) for 15 hours. Subsequently, the wood was removed from the solution and dried at room temperature (25°C) for 9 hours to obtain the composite of Example 1, which comprises wood and a flame retardant impregnated into the wood.

[0063] [Evaluation of flame retardancy performance by thermogravimetric differential thermal analysis (TG-DTA)] Thermogravimetric differential thermal analysis was performed on the composite material of Example 1. For comparison, thermogravimetric differential thermal analysis was performed on untreated wood that was not immersed in the solution. The results are shown in Figure 2. As shown in Figure 2, the composite material of Example 1 showed a shift in the peak heat generation temperature to the higher temperature side and a decrease in heat generation compared to untreated wood. Furthermore, the mass change was measured by thermogravimetric differential thermal analysis. As a result, the composite material of Example 1 had a mass of 5.0 mg before analysis, and the mass of the residue after analysis was 0.64 mg (remaining amount approximately 13%). In contrast, the untreated wood had a mass of 4.3 mg before analysis, and the mass of the residue after analysis was 0.020 mg (remaining amount approximately 0.47%). In other words, it was confirmed that the composite material of Example 1 exhibited suppressed combustion compared to the untreated wood.

[0064] [Example 2] A 99mm x 99mm x 15mm piece of wood (cedar) was immersed in an aqueous solution of the product obtained in the synthesis example, with a concentration of 0.045 mol / L, at room temperature (25°C) for 24 hours. Subsequently, the wood was removed from the solution and dried at room temperature (25°C) for 16 hours to obtain the composite of Example 2, which comprises wood and a flame retardant impregnated into the wood.

[0065] [Evaluation of flame retardancy performance by exothermic testing 1] A cooling curve measurement test (CCM Test) was performed on the composite material of Example 2. For comparison, a cooling curve measurement test was also performed on untreated wood that was not immersed in the solution. The results are shown in Figure 3. Figure 3 shows the heat generation rate (HRR) of the composite material and untreated wood. From the results shown in Fig. 3, it was confirmed that the composite of Example 2 had a decreased heat generation rate compared to the untreated wood. Also, it was confirmed that the composite of Example 2 had a delayed thermal decomposition compared to the untreated wood. Also, the mass change by the cooling curve measurement test was measured. As a result, for the composite of Example 2, the mass before analysis was 61.5 g, and the mass of the residue after analysis was 4.8 g (remaining amount approximately 7.8%). In the composite of Example 2, the mass of the wood before impregnating with the solution was 57.9 g, the mass of the wood after impregnating with the solution was 83.3 g, the concentration of the solution containing the flame retardant was 0.0105 mass%, and the volume of the wood was 99×99×15×10 -9 m 3 It was. Also, for the untreated wood, the mass before analysis was 55.4 g, and the mass of the residue after analysis was 3.0 g (remaining amount approximately 7.8%). Based on the following formula (1), the content of the flame retardant was calculated for the composite of Example 2. As a result, the content of the flame retardant in the composite of Example 2 was 1.8 kg / m 3 It was. AC=(W1-W0)×C / (100×V1) (1) (In the formula, AC is the content of the flame retardant (kg / m 3 ), W0 is the mass (kg) of the wood before impregnating with the solution containing the flame retardant, W1 is the mass (kg) of the wood immediately after impregnating with the solution containing the flame retardant, C is the concentration (mass%) of the solution containing the flame retardant, and V1 is the volume (m 3 ) of the wood after impregnating with the solution containing the flame retardant.)

[0066] [Example 3] [Evaluation 2 of Flame Retardant Performance by Heat Generation Test] The heat generation test of the composite of Example 2 was conducted. As a comparison, the heat generation test of the wood not immersed in the solution (untreated) was conducted. The results are shown in Table 1 and Fig. 4. Fig. 4 is a diagram showing the total heat release (THR) of the composite and the untreated wood. Table 1 shows the results of the heat generation test for 5 minutes after the start of heating. Note that the certification criteria for flame retardant materials defined by the Japan Institute of Building Technology are as follows. (1) The total heat release within 5 minutes after the start of heating is 8 MJ / m 2The following conditions must be met: (2) For the first 5 minutes after heating begins, there should be no cracks or holes that penetrate to the back surface, which would be harmful from a fire safety standpoint. (3) For the first 5 minutes after heating begins, the heating rate remains at 200 kW / m² for at least 10 seconds. 2 Do not exceed this limit.

[0067] [Table 1]

[0068] From the results in Table 1 and Figure 4, it was confirmed that the composite material of Example 2 had a reduced total heat output compared to untreated wood. Furthermore, it was confirmed that the composite material of Example 2 had a reduced heat generation rate compared to untreated wood.

[0069] [Example 4] The product obtained in the synthesis example is 1.5 × 10⁻¹⁰ of an aqueous solution with a concentration of 0.050 mol / L. 2 A piece of wood (cedar) measuring 99mm x 99mm x 15mm was immersed in mL of solution at room temperature (25°C) and atmospheric pressure (1013.25hPa) for 24 hours. Subsequently, the wood was removed from the solution and dried at 50°C for 3 days to obtain the composite material of Example 4 (Sample 1), which comprises wood and a flame retardant impregnated into the wood. Furthermore, the composite of Example 4 (Sample 2) was obtained in the same manner as Sample 1, except that 1 mg of methylene blue was added to the aqueous solution described above.

[0070] [Observation of the surface and cross-section of the composite] The surface of sample 1, and the surface and cross-section of sample 2 were observed visually. The results are shown in Figures 5 to 7. Figure 5 is a photograph showing the surface state of sample 1 and sample 2 before impregnation with the flame retardant, with sample 1 on the left and sample 2 on the right. Figure 6 is a photograph showing the surface state of sample 1 and sample 2 after impregnation with the flame retardant and drying, with sample 1 on the left and sample 2 on the right. Figure 7 is a photograph showing sample 2 cut along the dashed line shown in Figure 6, with the surface state of sample 2 on the left and the cross-sectional state of sample 2 on the right. The results shown in Figures 5 to 7 confirm that only the surface layer of sample 2 was colored, and that the flame retardant did not penetrate to the interior of sample 2.

[0071] [Example 5] An aqueous solution of the product obtained in the synthesis example, with a concentration of 0.045 mol / L, was applied to a piece of wood (cedar) measuring 99 mm x 99 mm x 15 mm. Subsequently, the wood was dried at room temperature (25°C) for 24 hours, followed by drying at 60°C for 24 hours, and then further dried at 23°C under 50% RH humidity for 10 days to obtain the composite of Example 5, which comprises wood and a flame retardant impregnated into the wood.

[0072] [Evaluation of flame retardancy performance by exothermic testing 3] A cooling curve measurement test (CCM Test) was performed on the composite material of Example 5. For comparison, a cooling curve measurement test was also performed on wood that was not immersed in the solution (untreated). The maximum heating rate during the first 5 minutes after heating begins is 170.4 kW / m². 2 The untreated wood has a ferrous flux of 208.9 kW / m³. 2 Since the value was lower, it was confirmed that the composite of Example 5 exhibited a reduced heat generation rate compared to untreated wood. Furthermore, the flame retardant content of the composite of Example 5 was calculated based on the above formula (1). As a result, the flame retardant content of the composite of Example 5 was 1.8 kg / m³. 3 That was the case.

[0073] [Example 6] In the synthesis example, a 99mm x 99mm x 15mm piece of wood (cedar) was immersed in an aqueous solution of the product obtained in the synthesis example, with a concentration of 0.045 mol / L. The wood was then left to stand under reduced pressure of 80 kPa at room temperature (25°C) for 1 hour for vacuum impregnation, followed by pressure impregnation under a pressure of 0.8 MPa at room temperature (25°C) for 1 hour. Subsequently, the wood was dried at room temperature (25°C) for 24 hours, followed by drying at 60°C for 24 hours, and then further dried at 23°C under 50% RH humidity for 6 days to obtain the composite of Example 6, which comprises wood and a flame retardant impregnated into the wood.

[0074] [Evaluation of flame retardancy performance by exothermic testing 4] A cooling curve measurement test (CCM Test) was performed on the composite of Example 6. The maximum heat generation rate during the first 5 minutes after heating begins is 142.9 kW / m². 2 The untreated wood has a ferrous flux of 208.9 kW / m³. 2 Since the value was lower, it was confirmed that the composite of Example 6 had a reduced heat generation rate compared to the untreated wood. Furthermore, the flame retardant content of the composite of Example 6 was calculated based on the above formula (1). As a result, the flame retardant content of the composite of Example 6 was 4.8 kg / m³. 3 That was the case.

Claims

1. A flame retardant comprising at least one of a silatran glycolate dimer represented by the following chemical formula (1) and a silatran glycolate tetramer represented by the following chemical formula (2). 【Chemistry 1】 【Chemistry 2】

2. A composite comprising wood and a flame retardant according to claim 1 impregnated into the wood.

3. A method for producing a flame retardant, comprising the step of reacting silicon dioxide and triethanolamine in glycol to synthesize at least one of the following: a dimer of silatran glycolate represented by the following chemical formula (1), a tetramer of silatran glycolate represented by the following chemical formula (2), and a monomer of silatran glycolate represented by the following chemical formula (3). 【Transformation 3】 【Chemistry 4】 【Transformation 5】

4. The method for producing a flame retardant according to claim 3, wherein the silicon dioxide is a component mainly contained in silica gel or a component mainly contained in rice straw ash.

5. The method for producing a flame retardant according to claim 3, wherein the glycol is ethylene glycol.

6. A step of preparing a solution containing the flame retardant by dissolving the flame retardant described in claim 1 in a solvent, A step of immersing the wood in the solution or applying the solution to the surface of the wood to impregnate the wood with the flame retardant, A method for producing a composite, comprising the step of drying wood impregnated with the aforementioned solution.

Images