A smoke-suppressing and flame-retardant liquid based on KH550, a preparation method and application thereof

Abstract

The application discloses a smoke-suppressing and flame-retardant liquid based on KH550, which uses ammonium dihydrogen phosphate ADP, phytic acid PA and guanazole GZ as main raw materials and uses gamma-aminopropyl triethoxysilane KH550 as a coupling assistant, has the effects of improving the interaction force between ADP, PA, GZ and the surface of wood and providing silicon elements to form a high-stability structure Si-O. The preparation method comprises the following steps: 1, preparation of a phytic acid-guanazole polyelectrolyte solution PG; 2, preparation of the smoke-suppressing and flame-retardant liquid ADP / KH550 / PG. When the smoke-suppressing and flame-retardant liquid is applied as a wood flame-retardant liquid, the smoke-suppressing and flame-retardant liquid has the flame-retardant property, can pass the UL-94 V-0 level test in the UL-94 level test, the residual carbon layer formed after combustion is in a large-area continuous and dense state, the limiting oxygen index is 38.4±1%, the maximum heat release rate is 41.31±2.51kW / m 2 , the total heat release amount is 6.15±0.94MJ / m 2 , the total smoke release amount is 0.26±0.01m 2 , the fire growth index is 0.31±0.02kW / m 2 / s, and the residual carbon amount at 800 DEG C is 40.96±1wt.%.​​​​

Description

Technical Field

[0001] This invention relates to the field of flame retardant materials, specifically to a smoke-suppressing and flame-retardant liquid based on KH550, its preparation method, and its application. Background Technology

[0002] Wood is an abundant resource, green and renewable, and highly processable. However, wood itself is highly flammable, posing a serious fire safety hazard. Therefore, it is essential to improve the flame retardancy of wood in practical applications. Currently, the simplest and most efficient method for modifying wood to be flame-retardant is to impregnate the wood with a flame-retardant liquid to enhance its flame-retardant properties.

[0003] For example, in existing literature 1 (Enhancing flame-retardant and smoke-suppression properties of wooden materials with phytic acid-added composite flameretardants [J]. Industrial Crops & Products 220(2024)119223), firstly, cedar wood is deligated under hydrothermal heating and soaking conditions using peracetic acid, hydrogen peroxide, sodium hydroxide, and trisodium citrate. Then, the deligated wood is impregnated in a flame-retardant liquid prepared by phytic acid, sodium silicate, nano-silica, and aluminum hydroxide, and repeated vacuum impregnation is performed to impregnate the flame-retardant liquid into the pores of the wood, thus obtaining flame-retardant wood. This technical solution achieves a UL-94V-0 rating and improves flame-retardant and smoke-suppression performance, significantly reducing heat release and smoke release. However, the problem with this technical solution is that it requires deligation treatment of the wood and the use of a cyclic vacuum impregnation method. Obviously, the above problems directly lead to an increase in the production process of preparing flame-retardant wood. The reason is that the core technical principle of this solution is that aluminum hydroxide, sodium silicate, and nano-silica in the flame retardant liquid can form a dense cross-linked protective carbon layer on the surface of the wood during combustion, thereby protecting the wood matrix. However, since the flame retardant liquid in this solution uses sodium silicate and nano-silica, the basic properties of these two substances determine their poor compatibility with wood. This characteristic directly leads to the inability to effectively penetrate the wood during impregnation. Therefore, the solution of this technical solution is to pre-treat the wood with lignin. At the same time, in order to further improve the impregnation effect, a complicated cyclic vacuum impregnation method is adopted.

[0004] In order to improve the compatibility problem, the compatibility problem can be improved by introducing a component containing a component capable of interacting with the wood surface, such as forming hydrogen bonds, in the flame retardant liquid. For example, in the prior art 2 (Flame retardant modification of poplar wood based on sustainable impregnation solution with high biomass content [J]. Industrial Crops & Products 215 (2024) 118616), a bio-based flame retardant liquid is prepared by using phytic acid, urea and furfuryl alcohol as raw materials, and the bio-based flame retardant liquid is successfully impregnated into the wood surface by (single) vacuum impregnation method, and the flame retardant wood is obtained. The technical scheme also realizes UL-94V-0 level, and the limiting oxygen index reaches 36.3%, in addition, the total heat release and total smoke release are reduced by 48.9% and 79.8% respectively. The technical scheme introduces urea and furfuryl alcohol, which has the characteristics of rich amino and hydroxyl groups to form hydrogen bonds, so as to realize the similar technical effect of prior art 1 without delignification treatment and only using single vacuum impregnation method. However, the technical scheme still needs to use vacuum impregnation method, that is, only the step of delignification treatment is reduced. In addition, the technical scheme also has the problem that the inhibition effect of the wood heat release and smoke release does not meet the application requirements, and the reason is that only relying on phosphorus element cannot effectively form stable residual carbon layer. According to the research of the applicant, it is found that nitrogen element needs to be introduced, and the synergistic effect of nitrogen element on the dilution of oxygen in gas phase can further improve the flame retardant performance.

[0005] Through the analysis of the prior art, it can be known that the technical scheme based on the basic principle of the flame retardant liquid formed by the carbon layer of the phosphorus-containing compound and the silicon compound during combustion to protect the substrate and improve the flame retardant performance needs to improve the interaction force between the silicon-containing compound and the wood, that is, the problem of the prior art is that the interaction force between the silicon-containing compound and the wood is poor, and the interface compatibility between the wood is poor, resulting in complex process during flame retardant modification. SUMMARY

[0006] The purpose of the present application is to provide a KH550-based smoke suppression flame retardant liquid and its preparation method and application. In view of the process flow of the prior art, that is, the problem of using delignification treatment for wood, using vacuum impregnation method and other complex processes in the process flow, by introducing a phosphorus-nitrogen compound with hydrogen bond capable of interacting with the substrate as the main flame retardant component, and an organosilicon material with enhanced interaction effect as the secondary flame retardant component to prepare the flame retardant liquid, the purpose of further simplifying the process flow is achieved.

[0007] In order to achieve the above-mentioned purposes, the basic principle of the present application is,

[0008] The phosphorus-nitrogen compound is used to realize the hydrogen bond interaction with the matrix by containing a large number of hydroxyl and amino groups, and to enhance the interface compatibility; at the same time, in the combustion process, the phosphorus element promotes the dehydration and carbonization of the matrix to form a protective carbon layer, and the nitrogen element forms non-combustible gas to dilute oxygen, so as to improve the flame retardant performance of the matrix.

[0009] The silane coupling agent is used to effectively improve the interaction between the additive and the matrix by containing a large number of functional groups that can simultaneously couple with organic and inorganic materials; at the same time, in the combustion process, the silicon element forms a silicon-containing carbon layer with high stability, which improves the protection ability of the matrix, i.e. improves the flame retardant performance.

[0010] Specifically, ammonium dihydrogen phosphate ADP, phytic acid-guanazole polyelectrolyte PG are used as the main flame retardant components, and gamma-aminopropyl triethoxysilane KH550 is used as the secondary flame retardant component; wherein ADP and PG can both produce hydrogen bond interaction with the wood surface, improving the compatibility with the wood; KH550 acts as a coupling agent to enhance the compatibility of ADP and PG with wood, and as a silicon source to form a silicon-containing carbon layer after combustion, improving the stability of the protective carbon layer; finally, through the combined action of ADP, PG and KH550, an impregnation type flame retardant liquid can be prepared by using only a direct impregnation method, and flame retardant wood can be obtained.

[0011] In order to achieve the above-mentioned purposes, the technical solution adopted by the present application is:

[0012] A smoke suppression and flame retardant liquid based on KH550, ammonium dihydrogen phosphate ADP, phytic acid PA and guanazole GZ are used as the main raw materials, and gamma-aminopropyl triethoxysilane KH550 is used as a coupling agent.

[0013] The main role of ADP is to provide phosphorus and nitrogen elements, and to promote the dehydration and carbonization of the matrix to form a protective carbon layer and to form non-combustible gas to dilute oxygen to inhibit combustion.

[0014] The main role of PA is to increase the content of phosphorus element and promote the matrix to form a dense protective carbon layer.

[0015] The main role of GZ is to increase the content of nitrogen element and improve the effect of inhibiting combustion.

[0016] The main role of KH550 is to improve the interaction force between ADP, PA, GZ and the surface of the wood, thereby improving the flame retardant performance, and to provide silicon element to form a high-stability structure Si-O in combustion to promote the formation of a dense and stable protective carbon layer.

[0017] A preparation method of a smoke suppression and flame retardant liquid based on KH550, comprising the following steps:

[0018] Step 1, preparation of a phytic acid-guanazole polyelectrolyte solution PG, under certain conditions, guanazole GZ is dissolved in deionized water to obtain solution A, then 70wt.% phytic acid PA aqueous solution is added to solution A to obtain solution B, after the addition is completed, stirring reaction is carried out under certain conditions to obtain solution C, i.e. phytic acid-guanazole polyelectrolyte PA-GZ solution, abbreviated as PG;

[0019] In the step 1, the mass ratio of GZ, PA and deionized water is 2:2:100;

[0020] In the step 1, the conditions for dissolving GZ to prepare solution A are that the dissolution temperature is room temperature and the dissolution rotation speed is 300-400rpm;

[0021] In the step 1, the stirring reaction conditions of solution B are that the stirring temperature is room temperature, the stirring rotation speed is 300-400rpm and the stirring time is 0.5h;

[0022] Step 2, preparation of a smoke suppression and flame retardant liquid ADP / KH550 / PG, under certain conditions, ammonium dihydrogen phosphate ADP and γ-aminopropyl triethoxysilane KH550 are simultaneously added to the PG obtained in step 1 to obtain solution C, after the addition is completed, solution C is stirred under certain conditions to obtain a smoke suppression and flame retardant liquid based on KH550, named ADP / KH550 / PG;

[0023] In the step 2, the mass ratio of ADP, KH550 and PG is 14:2:104;

[0024] In the step 2, the conditions for adding ADP and KH550 to prepare solution C are that the addition temperature is room temperature and the stirring rotation speed is 400-500rpm;

[0025] In the step 2, the stirring reaction conditions of solution C are that the stirring temperature is room temperature, the stirring rotation speed is 300-400rpm and the stirring time is 0.5h.

[0026] A smoke suppression and flame retardant liquid based on KH550, when applied as a wood flame retardant liquid, has flame retardant properties, the wood impregnated with the flame retardant liquid passes the UL-94 V-0 level test in the UL-94 level test, the residual carbon layer formed after combustion is in a large-area continuous dense state, in the limiting oxygen index test, the limiting oxygen index is 38.4±1%, in the cone calorimeter test, the maximum heat release rate is 41.31±2.51kW / m 2 , the total heat release is 6.15±0.94MJ / m 2 , and the total smoke release is 0.26±0.01m2 , the fire growth index is 0.31±0.02kW / m 2 / s. In the thermogravimetric test, the residual carbon content at 800℃ is 40.96±1wt.%.

[0027] The technical effect of the KH550-based smoke suppression flame retardant liquid obtained by the present application is tested as follows:

[0028] The TG test results show that the residual carbon content of wood impregnated with the flame retardant liquid obtained by the present application at 800℃ is 40.96±1wt.%. That is, the flame retardant liquid greatly improves the residual amount of wood at high temperature.

[0029] Further, the SEM test results of the residual carbon layer formed after the wood impregnated with the flame retardant liquid obtained by the present application is burned show that the residual carbon layer after the wood impregnated with the flame retardant liquid is burned exhibits the properties of large-area continuous and dense, that is, the flame retardant liquid can greatly improve the quality of the carbon layer after the wood is burned, and the high-quality carbon layer can isolate heat and oxygen during the combustion process, thereby improving the ability to protect the wood matrix and increasing the residual amount after the wood is burned.

[0030] The vertical burning and limiting oxygen index test results show that the wood impregnated with the flame retardant liquid obtained by the present application reaches the UL-94 V-0 level, and the limiting oxygen index is 38.4±1%, that is, the use of the flame retardant liquid can improve the UL-94 level and limiting oxygen index of wood. The introduction of KH550 has no substantial effect on the UL-94 level and limiting oxygen index of wood, that is, KH550 has no substantial effect on the flame retardant performance of wood.

[0031] The cone calorimeter test results show that compared with pure wood, the wood impregnated with the flame retardant liquid obtained by the present application has a 79.86% reduction in maximum heat release rate, a 73.17% reduction in total heat release, a 96.95% reduction in total smoke release, and a 79.47% reduction in fire growth index, that is, the impregnation of the flame retardant liquid can greatly reduce the heat and smoke released by the wood during combustion, and greatly reduce the fire hazard. The introduction of KH550 reduces the maximum heat release rate of the flame-retardant wood by 64.28%, the total heat release by 21.76%, the total smoke release by 60%, and the fire growth index by 70.47%. That is, the introduction of KH550 mainly improves the heat release rate suppression and smoke suppression performance, that is, the improvement effect on heat release rate suppression and smoke suppression performance is significant.

[0032] Therefore, the present application has the following advantages over the prior art:

[0033] 1. The present application uses KH550 as a coupling aid to successfully enhance the interfacial compatibility between phosphorus-nitrogen compounds and wood, thereby ultimately avoiding and reducing delignification and vacuum impregnation operations, and has the advantages of simple preparation process, green environmental protection, and low production cost.

[0034] 2、The smoke suppression and flame retardant liquid prepared by the present application has significantly improved effect of wood flame retardation and smoke suppression. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 FT-IR graph of PG prepared for Example 1;

[0036] Figure 2 SEM and EDS graphs of the surface of Example 1;

[0037] Figure 3 TG graphs of Example 1, Reference Example, Comparative Example 1, Comparative Example 2;

[0038] Figure 4 SEM graphs of the carbon layer of the carbon residue after combustion of Example 1, Reference Example, wherein Figure 4 a is the Reference Example, Figure 4 b is Example 1;

[0039] Figure 5 Vertical burning test graphs of Example 1, Reference Example, Comparative Example 1, Comparative Example 2, Comparative Example 3, wherein Figure 5 a is before the vertical burning test, Figure 5 b is after the vertical burning test;

[0040] Figure 6 Vertical burning grade and limiting oxygen index data of Example 1, Reference Example, Comparative Example 1, Comparative Example 2, Comparative Example 3;

[0041] Figure 7 Conical calorimetric test graphs of Example 1, Reference Example, Comparative Example 1, Comparative Example 2, Comparative Example 3;

[0042] Figure 8 Pictures after conical calorimetric test of Example 1, Reference Example, wherein the upper row is the Reference Example and the lower row is Example 1. DETAILED DESCRIPTION

[0043] The present application is further described in detail by embodiments in combination with the accompanying drawings of the specification, but is not limited to the present application.

[0044] Example 1

[0045] A preparation method of a smoke suppression and flame retardant liquid based on KH550, comprising the following steps:

[0046] Step 1, preparation of the phytic acid-guanazole polyelectrolyte solution PG, first, 2g of guanazole GZ was dissolved in 100g of deionized water at room temperature under the stirring speed of 400rpm to obtain solution A, then, 2g of 70wt.% phytic acid PA aqueous solution was added to solution A to obtain solution B, after the addition was completed, the phytic acid-guanazole polyelectrolyte PA-GZ solution, referred to as PG, was obtained by continuing to stir at room temperature under the stirring speed of 400rpm for 0.5h.

[0047] In order to prove the composition of PG, i.e. the successful synthesis of PG, FT-IR test was performed, and the test results are shown in Figure 1 The test results show that PG is successfully synthesized.

[0048] Step 2, preparation of the smoke suppression fire retardant solution ADP / KH550 / PG, 14g of ammonium dihydrogen phosphate ADP and 2g of γ-aminopropyl triethoxysilane KH550 were simultaneously added to PG obtained in step 1 to obtain solution C under the conditions of room temperature and stirring speed of 500rpm, after the addition was completed, solution C was stirred under the conditions of room temperature and stirring speed of 400rpm for 0.5h to obtain the smoke suppression fire retardant solution based on KH550, referred to as ADP / KH550 / PG.

[0049] In order to prove the technical effect of ADP / KH550 / PG as a wood fire retardant solution, the wood was impregnated in ADP / KH550 / PG to prepare fire retardant wood FRW for testing.

[0050] The specific preparation method of FRW is as follows: first, the wood was impregnated in ADP / KH550 / PG for 2h; then, the impregnated wood was dried to constant weight at the drying temperature of 60℃ for 12h to obtain fire retardant wood FRW. The FRW prepared based on the obtained ADP / KH550 / PG is named as ADP / KH550 / PG / FRW in the specific embodiment 1.

[0051] In order to prove that the fire retardant solution ADP / KH550 / PG is successfully impregnated into the wood, i.e. the successful preparation of the fire retardant wood ADP / KH550 / PG / FRW, SEM test and EDS test were performed. The test results are shown in Figure 2 The SEM test results show that the pores and surface of the wood are filled with substances, and the EDS test results show that the fillers contain C element, N element, O element, P element and Si element, and are uniformly dispersed. The test results show that the fire retardant solution ADP / KH550 / PG is successfully adhered to the surface of the wood by impregnation, and is uniformly dispersed.

[0052] In order to prove the thermal stability of ADP / KH550 / PG / FRW, TG test was carried out. The test results are shown in Table 1 and Figure 1. Figure 3 As shown in Table 1 and Figure 1, the temperature of ADP / KH550 / PG / FRW when the decomposition mass is 5% is 217.85℃, and the temperature when the maximum decomposition rate is reached is 293.92℃; the carbon residue amount at 800℃ is 40.96wt.%. The test results show that ADP / KH550 / PG / FRW has high thermal stability, and at the same time, it also has high carbon residue amount at high temperature.

[0053] Table 1 Thermal gravimetric test results

[0054]

[0055] In order to further prove the quality of the carbon residue layer of ADP / KH550 / PG / FRW, SEM test was carried out on the carbon residue layer formed after ADP / KH550 / PG / FRW was burned. The test results are shown in Table 1 and Figure 2. Figure 4 As shown in Table 1 and Figure 2, the carbon residue layer of ADP / KH550 / PG / FRW is in a large-area continuous and dense state. The test results show that the carbon residue layer formed after ADP / KH550 / PG / FRW is burned has high density, which can effectively isolate the contact between oxygen and heat and the inside of wood on the surface of wood, thereby improving the flame retardant performance.

[0056] In order to further prove the flame retardant performance of ADP / KH550 / PG / FRW, vertical burning test and limiting oxygen index test were carried out. The test results are shown in Table 1 and Figure 5 and Figure 6 As shown in Table 1 and Figure 3, ADP / KH550 / PG / FRW only has a bottom part burning after the vertical burning test, at the same time, passes the UL-94V-0 level, and the limiting oxygen index is as high as 38.4%. The test results show that the flame retardant performance of ADP / KH550 / PG / FRW is excellent.

[0057] In order to further prove the flame retardant and smoke suppression performance of ADP / KH550 / PG / FRW under real burning conditions, cone calorimeter test was carried out. The test results are shown in Table 2 and Figure 7 As shown in Table 2 and Figure 4, the maximum heat release rate of ADP / KH550 / PG / FRW is 41.31kW / m 2 , the total heat release amount is 6.15MJ / m 2 , the total smoke emission amount is 0.26m 2 , and the fire growth index is 0.31kW / m 2 / s. The test results show that the flame retardant and smoke suppression effect of ADP / KH550 / PG / FRW is excellent.

[0058] Table 2 Cone calorimeter test results

[0059]

[0060] To prove the effect of KH550 on the flame retardant performance of the flame retardant solution ADP / KH550 / PG, i.e. the role of KH550 in the technical solution, Comparative Example 1, a flame retardant solution without adding KH550, is provided. At the same time, in order to facilitate comparative analysis, the test results of pure wood without impregnating ADP / KH550 / PG are provided as a reference example.

[0061] Reference Example

[0062] A pure wood without impregnating ADP / KH550 / PG, referred to as pure wood.

[0063] The TG test results of pure wood are shown in Figure 3 , and the residual carbon content at 800℃ is 10.15wt.%. Compared with Example 1, it can be seen that impregnating ADP / KH550 / PG increases the residual carbon content of wood at 800℃ by 30.81wt.%, i.e. impregnating ADP / KH550 / PG greatly increases the residual carbon content of wood at high temperature.

[0064] The SEM test results of the residual carbon layer after complete combustion of pure wood are shown in Figure 4 , and the residual carbon layer of pure wood is completely broken, and there are many broken fiber structures. Compared with Example 1, it can be seen that impregnating ADP / KH550 / PG makes the residual carbon layer of wood become continuous and dense, i.e. the quality of the residual carbon layer is greatly improved.

[0065] The vertical burning test and limiting oxygen index test results of pure wood are shown in Figure 5 and Figure 6 In the vertical burning test, the pure wood completely burns and fails to pass the UL-94 rating test, and its limiting oxygen index is 18.9%. Compared with Example 1, it can be seen that impregnating ADP / KH550 / PG can improve the UL-94 rating of wood from failing the test to V-0, and at the same time, the limiting oxygen index is greatly improved from 18.9% to 38.4%, with an improvement of 203.17%, i.e. impregnating ADP / KH550 / PG significantly improves the flame retardant performance of wood.

[0066] The cone calorimeter test results of pure wood are shown in Figure 7 and Table 2. In the cone calorimeter test, the maximum heat release rate of pure wood is 205.14kW / m 2 , the total heat release is 22.92MJ / m 2 , the total smoke release is 8.54m 2 , and the fire growth index is 1.51kW / m 2Compared with Example 1, it can be seen that impregnating ADP / KH550 / PG makes the maximum heat release rate of the flame-retardant wood decrease by 79.86%, the total heat release decrease by 73.17%, the total smoke emission decrease by 96.95%, and the fire growth index decrease by 79.47%. The test results show that impregnating ADP / KH550 / PG greatly improves the flame-retardant and smoke-suppressing performance of wood in real burning conditions and greatly reduces the fire hazard.

[0067] Comparative Example 1

[0068] A preparation method of a flame-retardant solution without adding KH550, without specifically stating the steps same as Example 1, the difference is that in the step 2, no KH550 is added, only ADP is added, and the obtained flame-retardant solution is named as ADP / PG, and the further obtained conventional flame-retardant wood is named as ADP / PG / FRW.

[0069] The vertical burning test and limiting oxygen index test results of ADP / PG / FRW are shown in Figure 5 and Figure 6 In the vertical burning test, ADP / KH550 / FRW partially burns, passes the UL-94 V-0 level test, and its limiting oxygen index is 37.6%.

[0070] Compared with Example 1, it can be seen that introducing KH550 has no substantial effect on the UL-94 level of the flame-retardant wood, and has negligible effect on the limiting oxygen index, that is, no substantial effect, that is, the test results show that introducing KH550 has no substantial effect on the flame-retardant performance.

[0071] The cone calorimeter test results of ADP / PG / FRW are shown in Figure 7 and Table 2, the maximum heat release rate of ADP / PG / FRW is 115.66 kW / m 2 , the total heat release is 7.86 MJ / m 2 , the total smoke emission is 0.65 m 2 , and the fire growth index is 1.05 kW / m 2 / s.

[0072] Compared with Comparative Example 1, it can be seen that impregnating ADP / PG makes the maximum heat release rate of the flame-retardant wood decrease by 43.61%, the total heat release decrease by 65.71%, the total smoke emission decrease by 92.39%, and the fire growth index decrease by 30.46%. The test results show that impregnating ADP / PG mainly improves the total heat release and smoke suppression performance, that is, the improvement effect on the total heat release and smoke suppression performance is significant.

[0073] Compared with Example 1, the use of KH550 makes the maximum heat release rate of the flame-retardant wood decrease by 64.28%, the total heat release amount decrease by 21.76%, the total smoke release amount decrease by 60%, and the fire growth index decrease by 70.47%. The test results show that the introduction of KH550 mainly improves the heat release rate and smoke suppression performance, i.e., the improvement effect on the heat release rate and smoke suppression performance is significant.

[0074] As can be seen from Example 1, Comparative Example and Comparative Example 1, KH550 and ADP / PG can both improve the flame-retardant performance, i.e., reduce the fire hazard of wood, but the roles in the technical solutions are different. Specifically, the main role of ADP / PG is to improve the UL-94 grade and limiting oxygen index of wood and reduce the total heat release amount and total smoke release amount to improve the flame-retardant performance; and the main role of KH550 is to reduce the maximum heat release rate and fire growth index to improve the flame-retardant performance.

[0075] The reason is that the mechanism of KH550 to improve the flame-retardant performance is that the thermal decomposition of KH550 produces a structure containing Si-O, which can cross-link with P-O and N-O structures produced by the decomposition of phosphorus-nitrogen compounds in the flame-retardant liquid, thereby forming a cross-linked structure with high stability, promoting the formation of a stable carbon residue layer with high compactness, and further improving the heat insulation capacity of the carbon residue layer, reducing the heat conduction during combustion, suppressing the heat release rate during wood combustion, and reducing the fire hazard of wood; in addition, KH550 can increase the interaction force between phosphorus-nitrogen compounds and the surface of wood through hydrogen bonding, which is conducive to the promotion of dehydration and carbonization of wood by phosphorus-containing components during wood combustion, improves the flame-retardant improvement effect of flame-retardant components on wood, and further reduces the total heat release amount and total smoke release amount.

[0076] In order to further confirm the influence of PG on the flame-retardant performance of the flame-retardant liquid ADP / KH550 / PG, i.e., the role in the technical solution, Comparative Example 2 is provided, which is a flame-retardant liquid without adding PG.

[0077] Comparative Example 2

[0078] A preparation method of a flame-retardant liquid without adding PG, the steps are not particularly specified and are the same as those in Example 1, except that the step 1 is not required, and in the step 2, no PG solution is added, but ADP and KH550 are directly added to 100 g of deionized water, and the obtained flame-retardant liquid is named ADP / KH550, and the further obtained flame-retardant wood is named ADP / KH550 / FRW.

[0079] The TG test results of ADP / KH550 / FRW are shown in Figure 3 The carbon residue amount of ADP / KH550 / FRW at 800℃ is 34.67wt.%.

[0080] Compared with Example 1, it can be seen that the introduction of PG increases the char content of wood at 800°C by 6.29 wt.%, which proves that the introduction of PG increases the char content of flame-retardant wood at high temperatures.

[0081] The results of the vertical combustion test and limiting oxygen index test for ADP / KH550 / FRW are as follows: Figure 5 and Figure 6 As shown, in the vertical combustion test, the ADP / KH550 / FRW partially burned, passed the UL-94V-0 rating test, and its limiting oxygen index was 34.9%.

[0082] Compared with Example 1, it can be seen that the introduction of PG has no substantial effect on the UL-94 rating of flame-retardant wood. However, it can reduce the burning portion and increase the limiting oxygen index from 34.9% to 38.4%. The test results show that the introduction of PG can improve the flame-retardant properties of wood.

[0083] The cone calorimetry test results of ADP / KH550 / FRW are as follows: Figure 7 As shown in Table 2, the maximum heat release rate of the ADP / KH550 / FRW is 81.77 kW / m³. 2 The total heat release is 12.33 MJ / m³. 2 The total smoke emission was 1.07m³. 2 The fire growth index is 0.58 kW / m³. 2 / s.

[0084] Compared with the reference ratio, impregnation with ADP / KH550 reduced the maximum heat release rate of flame-retardant wood by 60.14%, the total heat release by 46.20%, the total smoke emission by 88.17%, and the fire growth index by 61.59%. The test results indicate that impregnation with ADP / KH550 primarily improves the heat release rate and smoke suppression performance, demonstrating a significant effect on these aspects.

[0085] Compared with Example 1, the introduction of PG reduced the maximum heat release rate of the flame-retardant wood by 49.48%, the total heat release by 50.12%, the total smoke emission by 75.70%, and the fire growth index by 46.55%. The test results show that the introduction of PG mainly improved the total heat release and smoke suppression performance, that is, the improvement effect on the total heat release and smoke suppression performance is significant.

[0086] As can be seen from the reference examples and comparative examples 1 and 2, since both comparative examples 1 and 2 contain ADP, the influence of ADP on flame retardant performance can be eliminated, that is, the roles of PG and KH550 in the technical solution can be analyzed and proved.

[0087] PG and KH550 can both improve the flame retardant performance of wood and reduce the fire hazard of wood, but the roles in the technical solutions are different. As mentioned above, the main role of KH550 is to reduce the maximum heat release rate and fire growth index to improve the flame retardant performance; and the main role of PG is to improve the limiting oxygen index of wood and reduce the burning area, total heat release and total smoke release to improve the flame retardant performance.

[0088] The reason is that the mechanism of PG to improve the flame retardant performance is that, since PG contains a large amount of phosphorus and nitrogen elements, after adding PG, the increase of phosphoric acid group content can enhance the promotion of wood dehydration to form carbon, and promote the rapid formation of carbon layer to protect the wood matrix; at the same time, a large number of nitrogen-containing groups generate non-combustible gas mainly in the form of nitrogen gas during combustion, which plays a physical "blowout role", promotes the extinguishment of flame, so that the flame cannot continue to burn, and finally realizes the technical effects of reducing the combustion of wood, improving the limiting oxygen index, and reducing the heat release and smoke release.

[0089] In order to further confirm the influence of each component in PG on the performance of the flame retardant solution ADP / KH550 / PG, i.e. the role in the technical solution, comparative example 3 is provided, which is a flame retardant solution without adding GZ.

[0090] Comparative example 3

[0091] A preparation method of a flame retardant solution without adding GZ, the steps are not particularly specified and are the same as those in example 1, the difference is that in step 1, GZ is not added, but only PA solution is added, and the obtained flame retardant solution is named ADP / KH550 / PA, and the obtained flame retardant wood is named ADP / KH550 / PA / FRW.

[0092] The TG test results of ADP / KH550 / PA / FRW are shown in Figure 3 The carbon residue of ADP / KH550 / PA / FRW at 800℃ is 38.55wt.%.

[0093] Compared with comparative example 2, it can be seen that the introduction of PA increases the carbon residue of wood at 800℃ by 3.88wt.%, which proves that the introduction of PA increases the carbon residue of flame-retardant wood at high temperature.

[0094] Compared with example 1, it can be seen that the introduction of GZ increases the carbon residue of wood at 800℃ by 2.41wt.%, which proves that the introduction of GZ increases the carbon residue of flame-retardant wood at high temperature.

[0095] The vertical combustion test and limiting oxygen index test results of ADP / KH550 / PA / FRW are shown in Figure 5 and Figure 6As shown, in the vertical combustion test, the ADP / KH550 / PA / FRW partially burns, passes the UL-94 V-0 level test, and its limiting oxygen index is 35.4%.

[0096] As compared with Comparative Example 2, it can be seen that the introduction of PA has no substantial effect on the UL-94 level of the flame-retardant wood, the burning part is less, and the effect on the limiting oxygen index is negligible, i.e. no substantial effect, i.e. the test results show that the introduction of PA has no substantial effect on the flame-retardant property of the wood.

[0097] As compared with Example 1, it can be seen that the introduction of GZ has no substantial effect on the UL-94 level of the flame-retardant wood, the burning part is less, and the limiting oxygen index is increased from 35.4% to 38.4%, i.e. the test results show that the introduction of GZ can improve the flame-retardant property of the wood.

[0098] The cone calorimeter test results of ADP / KH550 / PA / FRW are shown in Table 3 and Figure 1. Figure 7 As shown in Table 2 and Table 3, the maximum heat release rate of ADP / KH550 / PA / FRW is 40.87 kW / m 2 , the total heat release is 7.49 MJ / m 2 , the total smoke release is 0.35 m 2 , and the fire growth index is 0.36 kW / m 2 / s.

[0099] As compared with the reference, it can be seen that the impregnation of ADP / KH550 / PA makes the maximum heat release rate of the flame-retardant wood decrease by 80.08%, the total heat release decrease by 67.32%, the total smoke release decrease by 95.90%, and the fire growth index decrease by 76.16%. The test results show that the impregnation of ADP / KH550 / PA mainly improves the heat release rate, the total heat release, and the smoke suppression performance, i.e. the improvement effect on the heat release rate, the total heat release, and the smoke suppression performance is significant.

[0100] As compared with Comparative Example 2, it can be seen that the introduction of PA makes the maximum heat release rate of the flame-retardant wood decrease by 50.02%, the total heat release decrease by 39.25%, the total smoke release decrease by 67.29%, and the fire growth index decrease by 37.93%. The test results show that the introduction of PA mainly improves the heat release rate and the smoke suppression performance, i.e. the improvement effect on the heat release rate and the smoke suppression performance is significant.

[0101] As compared with Example 1, it can be seen that the introduction of GZ makes the maximum heat release rate of the flame-retardant wood increase by 1%, the total heat release decrease by 17.89%, the total smoke release decrease by 25.71%, and the fire growth index decrease by 11.43%. The test results show that the introduction of GZ mainly improves the total heat release and the smoke suppression performance, i.e. the improvement effect on the total heat release and the smoke suppression performance is significant.

[0102] From Example 1, Comparative Example 2 and Comparative Example 3, the role of PG in the technical solution is derived from PA and GZ, respectively, wherein,

[0103] The main role of PA in the technical solution is to reduce the wood burning area, the maximum heat release rate, the total heat release and the total smoke release, thereby improving the flame retardant performance;

[0104] The main role of GZ in the technical solution is to improve the limiting oxygen index of wood, and reduce the burning area, the total heat release and the total smoke release, thereby improving the flame retardant performance.

[0105] The reason is that,

[0106] The mechanism of PA to improve the flame retardant performance is that it contains a large number of phosphorus-containing groups, which can effectively promote the dehydration of wood to form carbon, so that a dense carbon layer is formed on the surface of the wood to protect the wood matrix, thereby improving the ability of the carbon layer to insulate heat during combustion, and hindering the outflow of generated gas, thereby reducing the burning area, the maximum heat release rate, the total heat release and the total smoke release;

[0107] The mechanism of GZ to improve the flame retardant performance is that it contains a large number of nitrogen-containing groups, which generate nitrogen, ammonia and other non-combustible gases during wood combustion. The outflow of these gases not only has a physical "blowout effect" to promote the extinguishing of the flame, but also dilutes the oxygen in the air, making the flame unable to continue to burn, thereby reducing the burning part of the wood, improving the limiting oxygen index, reducing the heat and smoke release, and reducing the fire hazard.

[0108] From the Reference Example, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Example 1, the following conclusions can be drawn:

[0109] 1. Wood impregnated with the flame retardant liquid has a significantly improved flame retardant and smoke suppression performance compared to wood that has not been impregnated, and the fire growth index under real combustion conditions is also significantly reduced. The flame retardant liquid can effectively improve the flammable characteristics of wood, making it have high flame retardant and smoke suppression performance.

[0110] 2. The phytic acid-guanazole polyelectrolyte PG can effectively improve the flame retardant performance of the flame retardant liquid ADP / KH550 / PG / FRW. In PG, the main role of PA is to reduce the wood burning area, the maximum heat release rate, the total heat release and the total smoke release, thereby improving the flame retardant performance; the main role of GZ is to improve the limiting oxygen index of wood, and reduce the burning area, the total heat release and the total smoke release, thereby improving the flame retardant performance.

[0111] 3、KH550 can effectively enhance the improvement effect of the flame retardant liquid on the flame retardant performance of wood by enhancing the interaction force between phosphorus-nitrogen compounds and wood. In addition, KH550 itself forms high-stability substances such as silicon dioxide during combustion, which helps to improve the quality of the carbon layer and further promotes the flame retardant performance. The main role of KH550 is to reduce the maximum heat release rate and fire growth index, thereby improving the flame retardant performance.

Claims

1. A preparation method of a KH550-based smoke-suppressing flame-retardant liquid, characterized in that, Comprising the following steps: Step 1, preparation of phytic acid-guanazole polyelectrolyte solution PG, under the conditions of room temperature as the dissolving temperature and 300-400 rpm as the dissolving rotation speed, guanazole GZ is dissolved in deionized water to obtain solution A, then 70 wt.% phytic acid PA aqueous solution is added to solution A to obtain solution B, after the addition is completed, stirring reaction is carried out under the conditions of room temperature as the stirring temperature, 300-400 rpm as the stirring rotation speed and 0.5 h as the stirring time, to obtain phytic acid-guanazole polyelectrolyte PA-GZ solution, abbreviated as PG; In the step 1, the mass ratio of GZ, phytic acid PA aqueous solution and deionized water is 2:2:100; Step 2, preparation of KH550-based smoke suppression flame retardant solution, under the conditions of room temperature as the adding temperature and 400-500 rpm as the stirring rotation speed, ammonium dihydrogen phosphate ADP and γ-aminopropyl triethoxysilane KH550 are simultaneously added to the PG obtained in step 1, after the addition is completed, stirring reaction is carried out under the conditions of room temperature as the stirring temperature, 300-400 rpm as the stirring rotation speed and 0.5 h as the stirring time, to obtain the KH550-based smoke suppression flame retardant solution, named as ADP / KH550 / PG; In the step 2, the mass ratio of ADP, KH550 and PG is 14:2:

104.

2. The method of claim 1, wherein: When the obtained KH550-based smoke suppression flame retardant solution is applied as a wood flame retardant solution, it has flame retardant properties, the wood impregnated with the flame retardant solution passes the UL-94 V-0 level test in the UL-94 level test, and the residual carbon layer formed after the wood impregnated with the flame retardant solution burns is in a large-area continuous dense state.

3. The method of claim 1, wherein: When the obtained KH550-based smoke suppression flame retardant solution is applied as a wood flame retardant solution, the wood impregnated with the flame retardant solution has a limiting oxygen index of 38.4±1% in the limiting oxygen index test.

4. The method of claim 1, wherein: The obtained KH550-based smoke suppression and flame-retardant liquid is applied as a wood flame-retardant liquid, and the wood impregnated with the flame-retardant liquid has a maximum heat release rate of 41.31±2.51 kW / m 2 , a total heat release of 6.15±0.94 MJ / m 2 , a total smoke release of 0.26±0.01 m 2 , and a fire growth index of 0.31±0.02 kW / m 2 / s in a cone calorimeter test.

5. The method of claim 1, wherein: When the obtained KH550-based smoke suppression flame retardant solution is applied as a wood flame retardant solution, the wood impregnated with the flame retardant solution has a residual carbon amount of 40.96±1 wt.% at 800 ℃ in the thermogravimetric test.

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