KH550-based smoke suppression and flame retardance liquid as well as preparation method and application thereof

Abstract

Ammonium dihydrogen phosphate (ADP), phytic acid (PA) and guanazole (GZ) are taken as main raw materials, gamma-aminopropyltriethoxysilane KH550 is taken as a coupling aid, and the KH550 has the effects of improving the interaction force between ADP, PA and GZ and the surface of wood and providing a silicon element to form Si-O with a high-stability structure. The preparation method comprises the following steps: 1, preparing a phytic acid-guanidazole polyelectrolyte solution PG; and 2, preparation of the smoke suppression and flame retardation liquid ADP / KH550 / PG. When being used as a wood flame-retardant liquid, the flame-retardant liquid has flame-retardant property, and passes a UL-94V-0 grade test in a UL-94 grade test; a carbon residue layer formed after combustion is in a large-area continuous compact state; the limit oxygen index is 38.4 + / -1%; the maximum heat release rate is 41.31 + / -2.51 kW / m < 2 >, the total heat release amount is 6.15 + / -0.94 MJ / m < 2 >, the total smoke release amount is 0.26 + / -0.01 m < 2 >, and the fire increase index is 0.31 + / -0.02 kW / m < 2 > / s. And the carbon residue amount at 800 DEG C is 40.96 + / -1 wt.%.

Description

Technical Field

[0001] The invention relates to the field of flame retardant materials, and in particular to a smoke suppressant flame retardant liquid based on KH550, and a preparation method and application thereof. Background Art

[0002] Wood is abundant in resources, green and renewable, and highly processable. However, wood itself is highly flammable and poses a serious fire safety hazard. Therefore, the flame retardancy of wood must be improved in practical applications. Currently, the simplest and most efficient method for wood flame retardant modification is to impregnate wood with flame retardant liquid to improve its flame retardant properties.

[0003] For example, in the existing document 1 (Enhancing flame-retardant and smoke-suppression properties of wooden materials with phytic acid-added composite flameretardants [J]. Industrial Crops & Products 220 (2024) 119223), first, the fir is delignified by peracetic acid, hydrogen peroxide, sodium hydroxide and trisodium citrate under hydrothermal heating and soaking conditions, and then the delignified wood is immersed in a flame retardant liquid prepared by phytic acid, sodium silicate, nano-silicon dioxide and aluminum hydroxide, and repeated vacuum impregnation is performed to impregnate the flame retardant liquid into the pores of the wood to obtain flame-retardant wood. This technical solution achieves the UL-94V-0 grade, and improves the flame retardant and smoke suppression properties, and greatly reduces the heat release and smoke release. However, the problem with this technical solution is that the wood needs to be delignified and a cyclic vacuum impregnation method is used. Obviously, the above problems directly lead to an increase in the production process for preparing flame-retardant wood. The reason is that the core technical principle adopted by this technical solution is that the aluminum hydroxide, sodium silicate and nano-silicon dioxide 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 of this technical solution uses sodium silicate and nano-silicon dioxide, the basic properties of these two substances determine that they have poor compatibility with wood. This feature directly leads to the inability to effectively immerse the wood during impregnation. Therefore, the solution of this technical solution is to delignify the wood in advance. 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 above compatibility problems, it can be improved by introducing components that can interact with the wood surface, such as forming hydrogen bonds, into the flame retardant liquid. For example, in the existing document 2 ("Flame retardant modification of poplar wood based on sustainable impregnation solution with high biomass content" [J]. Industrial Crops & Products 215 (2024) 118616), phytic acid, urea and furfuryl alcohol are used as raw materials to prepare a bio-based flame retardant liquid, and the bio-based flame retardant liquid is successfully impregnated into the wood surface by a (single) vacuum impregnation method to obtain flame-retardant wood. This technical solution also achieves the UL-94V-0 rating, and the limiting oxygen index reaches 36.3%. In addition, the total heat release and total smoke release also decreased by 48.9% and 79.8%, respectively. This technical solution introduces urea and furfuryl alcohol, and utilizes the characteristics of urea and furfuryl alcohol being rich in amino groups and hydroxyl groups to form hydrogen bonds, thereby achieving a technical effect similar to that of the existing document 1 by only using a single vacuum impregnation method without delignification treatment. However, this technical solution still needs to adopt the vacuum impregnation method, that is, it only reduces the step of delignification treatment. In addition, this technical solution also has the problem that the inhibitory effect on the heat release and smoke release of wood does not meet the application requirements, and the reason is that it is impossible to effectively form a stable residual carbon layer by relying solely on phosphorus. According to the research of the applicant, it is necessary to introduce nitrogen element, and utilize nitrogen element to achieve the synergistic effect formed by diluting oxygen in the gas phase, which can further improve the flame retardant properties.

[0005] Through the analysis of the prior art, it can be known that the technical solution based on the basic principle of flame retardant liquid that forms a char layer to protect the matrix when phosphorus-containing compounds and silicon compounds burn, thereby improving the flame retardant performance, needs to improve the interaction between the silicon-containing compounds and the wood. That is, the problem with the prior art is that the interaction between the silicon-containing compounds and the wood is poor, and the interface compatibility with the wood is poor, resulting in complicated process during flame retardant modification. Summary of the invention

[0006] The purpose of the present invention is to provide a smoke suppression flame retardant liquid based on KH550 and its preparation method and application. Aiming at the problem of the process flow in the prior art, that is, the process flow requires the use of complex processes such as delignification of wood and vacuum impregnation, phosphorus and nitrogen compounds with hydrogen bonds that can interact with the matrix are introduced as the main flame retardant component, and organic silicon materials with enhanced interaction effects are used as secondary flame retardant components to prepare flame retardant liquid, so as to achieve the purpose of further simplifying the process flow.

[0007] In order to achieve the above-mentioned purpose of the invention, the basic principle of the present invention is:

[0008] Phosphorus-nitrogen compounds contain a large number of hydroxyl and amino groups to achieve hydrogen bond interaction with the matrix and enhance interfacial compatibility. At the same time, during the combustion process, phosphorus promotes the dehydration and carbonization of the matrix to form a protective carbon layer, and nitrogen forms non-flammable gas and dilutes oxygen through synergistic effects to improve the flame retardant properties of the matrix.

[0009] Silane coupling agents are used, which contain a large number of functional groups that can undergo coupling reactions with organic and inorganic materials at the same time, so as to effectively improve the interaction between the additive and the matrix; at the same time, during the combustion process, a highly stable silicon-containing carbon layer is formed through the silicon element, thereby improving the protection ability of the matrix, that is, improving the flame retardant performance.

[0010] Specifically, diammonium dihydrogen phosphate ADP and phytic acid-guanazole polyelectrolyte PG are used as the main flame retardant components, and γ-aminopropyltriethoxysilane KH550 is used as the secondary flame retardant component; wherein, both ADP and PG can produce hydrogen bonds with the wood surface to improve the compatibility with the wood; KH550 is used as a coupling agent to enhance the compatibility of ADP and PG with the wood, and as a silicon source, it can form a silicon-containing carbon layer after combustion to improve the stability of the protective carbon layer; finally, through the joint action of ADP, PG, and KH550, it is possible to prepare an impregnated flame retardant liquid and obtain flame-retardant wood by only using a direct impregnation method.

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

[0012] A smoke suppression and flame retardant liquid based on KH550, with diammonium phosphate ADP, phytic acid PA, and guanidine GZ as main raw materials, and γ-aminopropyltriethoxysilane KH550 as a coupling auxiliary agent;

[0013] The main function of the ADP is to provide phosphorus and nitrogen elements, and at the same time, it has the functions of promoting the dehydration of the substrate to form a protective carbon layer and forming a non-combustible gas to dilute the oxygen in the air to inhibit combustion;

[0014] The main function of PA is to increase the phosphorus content and promote the formation of a dense protective carbon layer on the matrix;

[0015] The main function of GZ is to increase the nitrogen content and improve the combustion suppression effect;

[0016] The main function of KH550 is to increase the interaction between ADP, PA, GZ and the wood surface, thereby improving the flame retardant performance. At the same time, it provides silicon elements to form a highly stable Si-O structure during combustion, promoting a dense and stable protective carbon layer.

[0017] A method for preparing a smoke suppressant and flame retardant liquid based on KH550 comprises the following steps:

[0018] Step 1, preparation of 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, referred to 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 speed is 300-400 rpm;

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

[0022] Step 2, preparation of smoke suppressant and flame retardant liquid ADP / KH550 / PG, under certain conditions, adding ammonium dihydrogen phosphate ADP and γ-aminopropyltriethoxysilane KH550 to the PG obtained in step 1 to obtain solution C, after the addition is completed, under certain conditions, stirring solution C to obtain a smoke suppressant and flame retardant liquid based on KH550, named ADP / KH550 / PG;

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

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

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

[0026] A smoke suppression flame retardant liquid based on KH550, which has flame retardant properties when used as a wood flame retardant liquid. The wood impregnated with the flame retardant liquid passes the UL-94V-0 grade test in the UL-94 grade test; the residual carbon layer formed after combustion is in a large-area continuous and dense state; in the limiting oxygen index test, the limiting oxygen index is 38.4±1%; in the cone calorimetry test, the maximum heat release rate is 41.31±2.51kW / m 2 The total heat release is 6.15±0.94MJ / m 2 The total smoke volume 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°C was 40.96±1wt.%.

[0027] The technical effects of the smoke suppression and flame retardant liquid based on KH550 obtained by the present invention have been tested as follows:

[0028] The TG test results show that the residual carbon content of the wood impregnated with the flame retardant liquid obtained in the present invention at 800° C. is 40.96±1wt.%, that is, the flame retardant liquid greatly increases the residual carbon content of the wood at high temperature.

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

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

[0031] The results of cone calorimetry test show that the maximum heat release rate of wood impregnated with the flame retardant liquid obtained by the present invention is reduced by 79.86% compared with pure wood, the total heat release is reduced by 73.17%, the total smoke release is reduced by 96.95%, and the fire growth index is reduced by 79.47%. That is, impregnation with flame retardant liquid can greatly reduce the heat and smoke released when wood burns, and greatly reduce the fire hazard. The introduction of KH550 reduces the maximum heat release rate of flame retardant wood by 64.28%, the total heat release is reduced by 21.76%, the total smoke release is reduced by 60%, and the fire growth index is reduced by 70.47%. That is, the introduction of KH550 mainly improves the suppression of heat release rate and smoke suppression performance, that is, the improvement effect of suppressing heat release rate and smoke suppression performance is significant.

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

[0033] 1. The present invention uses KH550 as a coupling agent to successfully enhance the interfacial compatibility between phosphorus and 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-suppressing and flame-retardant liquid prepared by the present invention has significantly improved the flame-retardant and smoke-suppressing effects on wood. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 FT-IR image of PG prepared in Example 1;

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

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

[0038] Figure 4 The SEM images of the carbon residue layer after combustion of Example 1 and the reference example are shown in FIG. Figure 4 a is the reference ratio, Figure 4 b is embodiment 1;

[0039] Figure 5 It is a vertical combustion test diagram of Example 1, Reference Example, Comparative Example 1, Comparative Example 2, and Comparative Example 3, wherein Figure 5 a is before vertical burning test, Figure 5 b is after vertical burning test;

[0040] Figure 6 The vertical combustion grade and limiting oxygen index data of Example 1, Reference Example, Comparative Example 1, Comparative Example 2, and Comparative Example 3 are shown;

[0041] Figure 7 Cone calorimetry test diagrams of Example 1, Reference Example, Comparative Example 1, Comparative Example 2, and Comparative Example 3;

[0042] Figure 8 These are pictures after cone calorimetry test of Example 1 and reference example, where the upper row is the reference example and the lower row is Example 1. DETAILED DESCRIPTION

[0043] The present invention is further described in detail through embodiments and in conjunction with the accompanying drawings, but the present invention is not limited thereto.

[0044] Example 1

[0045] A method for preparing a smoke suppressant and flame retardant liquid based on KH550 comprises the following steps:

[0046] Step 1, preparation of phytic acid-guanazole polyelectrolyte solution PG, first, at room temperature, 2g of guanazole GZ is placed in 100g of deionized water, and dissolved at a stirring speed of 400rpm to obtain solution A, then, 2g of 70wt.% phytic acid PA aqueous solution is added to solution A to obtain solution B, and after the addition is completed, at room temperature, the stirring speed is 400rpm, and the stirring time is 0.5h. Continue stirring to obtain a phytic acid-guanazole polyelectrolyte PA-GZ solution, referred to as PG;

[0047] In order to prove the composition of PG, i.e. the successful synthesis of PG, FT-IR test was carried out, and the test results are as follows Figure 1 As shown, PG contains characteristic peaks of both PA and GZ. The test results show that PG was successfully synthesized.

[0048] Step 2, preparation of smoke suppressant and flame retardant liquid ADP / KH550 / PG, at room temperature and a stirring speed of 500 rpm, 14 g of diammonium phosphate ADP and 2 g of γ-aminopropyltriethoxysilane KH550 are simultaneously added to the PG obtained in step 1 to obtain solution C. After the addition is completed, solution C is stirred at room temperature and a stirring speed of 400 rpm for a stirring time of 0.5 h to obtain a smoke suppressant and flame retardant liquid based on KH550, referred to as ADP / KH550 / PG.

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

[0050] The specific preparation method of FRW is as follows: first, the wood is impregnated in ADP / KH550 / PG for 2 hours; then, the impregnated wood is dried to a constant weight at a drying temperature of 60° C. for 12 hours to obtain the flame retardant wood FRW. Specific Example 1 The FRW prepared based on the obtained ADP / KH550 / PG is named ADP / KH550 / PG / FRW.

[0051] In order to prove that the flame retardant liquid ADP / KH550 / PG was successfully impregnated into the wood, that is, the flame retardant wood ADP / KH550 / PG / FRW was successfully prepared, SEM test and EDS test were carried out. The test results are shown in Figure 2 As shown, the SEM test results show that the pores and surface of the wood are filled with substances. Combined with the EDS test results, it can be confirmed that the fillers contain C, N, O, P and Si elements, and are evenly dispersed. The test results show that through the impregnation operation, the flame retardant liquid ADP / KH550 / PG successfully adheres to the wood surface and is evenly dispersed.

[0052] In order to prove the thermal stability of ADP / KH550 / PG / FRW, TG test was carried out. The test results are as follows Figure 3 As shown in Table 1, the temperature at which the decomposition mass of ADP / KH550 / PG / FRW is 5% is 217.85°C, and the temperature at which the maximum decomposition rate is reached is 293.92°C; the residual carbon content at 800°C is 40.96wt.%. The test results show that ADP / KH550 / PG / FRW has high thermal stability and high residual carbon content at high temperatures.

[0053] Table 1 Thermogravimetric test results

[0054]

[0055] In order to further prove the quality of the carbon residue layer of ADP / KH550 / PG / FRW, the carbon residue layer formed after the combustion of ADP / KH550 / PG / FRW was subjected to SEM test. The test results are as follows: Figure 4 As shown in the figure, the residual carbon layer of ADP / KH550 / PG / FRW is in a large, continuous and dense state. The test results show that the residual carbon layer formed after the combustion of ADP / KH550 / PG / FRW has a high density, which can effectively isolate the oxygen and heat on the wood surface from the contact with the inside of the 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 as follows Figure 5 and Figure 6 As shown in the figure, only the bottom part of ADP / KH550 / PG / FRW burns after the vertical burning test. At the same time, it passes the UL-94V-0 grade, and the limiting oxygen index is as high as 38.4%. The test results show that ADP / KH550 / PG / FRW has excellent flame retardant properties.

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

[0058] Table 2 Cone calorimetry test results

[0059]

[0060] In order to demonstrate the effect of KH550 on the flame retardant properties of the flame retardant liquid ADP / KH550 / PG, that is, its role in the technical solution, comparative example 1 is provided, which is a flame retardant liquid without adding KH550; at the same time, in order to facilitate comparative analysis, the test results of pure wood not impregnated with ADP / KH550 / PG are provided as a reference example.

[0061] Reference ratio

[0062] A pure wood that is not impregnated with ADP / KH550 / PG, referred to as pure wood.

[0063] The TG test results of pure wood are as follows Figure 3 As shown, the carbon residue at 800°C is 10.15wt.%. Compared with Example 1, it can be seen that the carbon residue of wood at 800°C increased by 30.81wt.%, which proves that the impregnation of ADP / KH550 / PG greatly increases the carbon residue of wood at high temperature.

[0064] The SEM test results of the carbon layer of the residual carbon after the pure wood is completely burned are as follows Figure 4 As shown in a, the carbon residue layer of pure wood is completely broken, and there are many broken fiber structures. Compared with Example 1, it can be seen that the carbon residue layer generated by the wood after impregnation with ADP / KH550 / PG becomes continuous and dense, that is, the quality of the carbon residue layer is greatly improved.

[0065] The results of the vertical combustion test and limiting oxygen index test of pure wood are as follows: Figure 5 and Figure 6 As shown, in the vertical burning test, the pure wood completely burned and failed the UL-94 grade test, and its limiting oxygen index was 18.9%. Compared with Example 1, it can be seen that the impregnation of ADP / KH550 / PG can improve the UL-94 grade of the 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%, and the improvement reaches 203.17%, that is, the impregnation of ADP / KH550 / PG significantly improves the flame retardant properties of the wood.

[0066] The cone calorimetry test results of pure wood are as follows Figure 7 As shown in Table 2, in the cone calorimetry test, the maximum heat release rate of pure wood is 205.14 kW / m 2 The total heat release is 22.92MJ / m 2 The total smoke volume is 8.54m 2 , the fire growth index is 1.51kW / m 2 / s. Compared with Example 1, it can be seen that the impregnation of ADP / KH550 / PG reduces the maximum heat release rate of the flame-retardant wood by 79.86%, the total heat release by 73.17%, the total smoke release by 96.95%, and the fire growth index by 79.47%. The test results show that the impregnation of ADP / KH550 / PG greatly improves the flame retardant and smoke suppression properties of wood in real combustion conditions, and greatly reduces the fire hazard.

[0067] Comparative Example 1

[0068] A method for preparing a flame retardant liquid without adding KH550, wherein the steps not specifically stated are the same as those of Example 1, except that: in step 2, no KH550 is added, and only ADP is added. The obtained flame retardant liquid is named ADP / PG, and the obtained conventional flame retardant wood is further named ADP / PG / FRW.

[0069] The vertical burning test and limiting oxygen index test results of ADP / PG / FRW are as follows Figure 5 and Figure 6 As shown, in the vertical burning test, ADP / KH550 / FRW partially burned, passed the UL-94V-0 rating test, and its limiting oxygen index was 37.6%.

[0070] Compared with Example 1, it can be seen that the introduction of KH550 has no substantial effect on the UL-94 grade of flame retardant wood. At the same time, the effect on the limiting oxygen index is negligible, that is, there is no substantial effect. That is, the test results show that the introduction of KH550 has no substantial effect on the flame retardant properties.

[0071] Cone calorimetry test results of ADP / PG / FRW are as follows Figure 7 As shown in Table 2, the maximum heat release rate of ADP / PG / FRW is 115.66kW / m 2 The total heat release is 7.86MJ / m 2 The total smoke volume is 0.65m 2 , the fire growth index is 1.05kW / m 2 / s.

[0072] Compared with the reference, the impregnation of ADP / PG reduced the maximum heat release rate of flame-retardant wood by 43.61%, the total heat release by 65.71%, the total smoke release by 92.39%, and the fire growth index by 30.46%. The test results show that the impregnation of 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 reduces the maximum heat release rate of 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%. The test results show that the introduction of KH550 mainly improves the suppression of heat release rate and smoke suppression performance, that is, the improvement effect on the suppression of heat release rate and smoke suppression performance is significant;

[0074] It can be seen from Example 1, Reference Example and Comparative Example 1 that although KH550 and ADP / PG can both improve the flame retardant properties, that is, reduce the fire hazard of wood, they play different roles in the technical scheme. 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 and total smoke release to improve the flame retardant properties; while the main role of KH550 is to reduce the maximum heat release rate and fire growth index to improve the flame retardant properties.

[0075] The reason is that the mechanism by which KH550 improves the flame retardant performance is that KH550 decomposes under heat to produce a Si-O-containing structure, and Si-O can cross-link with the PO structure and NO structure produced by the decomposition of phosphorus and nitrogen compounds in the flame retardant liquid, thereby forming a cross-linked structure with high stability, promoting the formation of a highly dense, stable residual carbon layer, thereby improving the heat insulation ability of the residual carbon layer, reducing heat conduction during combustion, and inhibiting the heat release rate during wood combustion, thereby reducing the fire hazard of wood; in addition, KH550 can increase the interaction force between phosphorus and nitrogen compounds and the wood surface through hydrogen bonds, which is beneficial to the promotion of the dehydration and carbonization of wood by phosphorus-containing components during wood combustion, and improving the flame retardant improvement effect of flame retardant components on wood, thereby further reducing the total heat release and total smoke release.

[0076] In order to further confirm the effect of PG on the flame retardant properties of the flame retardant liquid ADP / KH550 / PG, that is, its 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 method for preparing a flame retardant liquid without adding PG, wherein the steps not specifically stated are the same as those of Example 1, except that: step 1 is not required, and in step 2, no PG solution is added, but ADP and KH550 are directly added to 100 g of deionized water. The obtained flame retardant liquid is named ADP / KH550, and the obtained flame retardant wood is further named ADP / KH550 / FRW.

[0079] The TG test results of ADP / KH550 / FRW are as follows Figure 3 As shown, the carbon residue of ADP / KH550 / FRW at 800°C is 34.67wt.%.

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

[0081] The vertical burning test and limiting oxygen index test results of ADP / KH550 / FRW are as follows Figure 5 and Figure 6 As shown, in the vertical burning test, ADP / KH550 / FRW partially burned, passed the UL-94 V-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 grade of the flame retardant wood, but can reduce the burning portion. At the same time, the limiting oxygen index is increased from 34.9% to 38.4%. That is, the test results show that the introduction of PG can improve the flame retardant properties of wood.

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

[0084] Compared with the reference, impregnation with ADP / KH550 reduces the maximum heat release rate of flame-retardant wood by 60.14%, the total heat release by 46.20%, the total smoke release by 88.17%, and the fire growth index by 61.59%. The test results show that impregnation with ADP / KH550 mainly improves the heat release rate and smoke suppression performance, that is, the improvement effect on the heat release rate and smoke suppression performance is significant;

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

[0086] It can be seen from the reference example and comparative examples 1 and 2 that since comparative examples 1 and 2 both contain ADP, the influence of ADP on the flame retardant properties can be excluded, that is, the respective roles of PG and KH550 in the technical solution are analyzed and proved.

[0087] Although both PG and KH550 can improve the flame retardant properties of wood and reduce the fire hazard of wood, they play different roles in the technical solutions. As mentioned above, the main role of KH550 is to reduce the maximum heat release rate and fire growth index, thereby improving the flame retardant properties; while the main role of PG is to increase the limiting oxygen index of wood, and reduce the combustion area, total heat release and total smoke release, thereby improving the flame retardant properties.

[0088] The reason is that the mechanism by which PG improves the flame retardant properties is that PG contains a large amount of phosphorus and nitrogen elements. Therefore, after adding PG, the increase in the content of phosphate groups can enhance the dehydration of wood into carbon, and promote the rapid formation of a residual carbon layer that protects the wood matrix; at the same time, a large number of nitrogen-containing groups generate non-flammable gases mainly composed of nitrogen during combustion, which play a physical "blowing out effect" and promote the extinguishing of the flame, so that the flame cannot continue to burn, and ultimately achieve the technical effect of reducing the burned part of the wood, increasing the limiting oxygen index, and reducing the heat and smoke release.

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

[0090] Comparative Example 3

[0091] A method for preparing a flame retardant liquid without adding GZ, wherein the steps not specifically stated are the same as those of Example 1, except that: in step 1, GZ is not added, but only PA solution is added, the obtained flame retardant liquid is named ADP / KH550 / PA, and the obtained flame retardant wood is further named ADP / KH550 / PA / FRW.

[0092] The TG test results of ADP / KH550 / PA / FRW are as follows Figure 3 As shown, the carbon residue of ADP / KH550 / PA / FRW at 800°C 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°C by 3.88wt.%, which proves that the introduction of PA increases the carbon residue of flame-retardant wood at high temperatures.

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

[0095] The vertical burning test and limiting oxygen index test results of ADP / KH550 / PA / FRW are as follows Figure 5 and Figure 6As shown, in the vertical burning test, ADP / KH550 / PA / FRW partially burned, passed the UL-94V-0 rating test, and its limiting oxygen index was 35.4%.

[0096] Compared with Comparative Example 2, it can be seen that the introduction of PA has no substantial effect on the UL-94 rating of flame-retardant wood, and its burning portion becomes less. At the same time, the effect on the limiting oxygen index is negligible, that is, there is no substantial effect. That is, the test results show that the introduction of PA has no substantial effect on the flame retardant properties of wood.

[0097] Compared with Example 1, it can be seen that the introduction of GZ has no substantial effect on the UL-94 grade of the flame retardant wood, the burning portion is reduced, and at the same time, the limiting oxygen index is increased from 35.4% to 38.4%. That is, the test results show that the introduction of GZ can improve the flame retardant properties of wood.

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

[0099] Compared with the reference, the impregnation of ADP / KH550 / PA reduced the maximum heat release rate of flame-retardant wood by 80.08%, the total heat release by 67.32%, the total smoke release by 95.90%, and the fire growth index by 76.16%. The test results show that the impregnation of ADP / KH550 / PA mainly improves the heat release rate, total heat release and smoke suppression performance, that is, the improvement effect on the heat release rate, total heat release and smoke suppression performance is significant;

[0100] Compared with comparative example 2, the introduction of PA reduces the maximum heat release rate of flame-retardant wood by 50.02%, the total heat release by 39.25%, the total smoke release by 67.29%, and the fire growth index by 37.93%. The test results show that the introduction of PA mainly improves the heat release rate and smoke suppression performance, that is, the effect of improving the heat release rate and smoke suppression performance is significant;

[0101] Compared with Example 1, the introduction of GZ increased the maximum heat release rate of flame-retardant wood by 1%, decreased the total heat release by 17.89%, decreased the total smoke release by 25.71%, and decreased the fire growth index by 11.43%. The test results show that the introduction of GZ 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;

[0102] It can be seen from Example 1, Comparative Example 2 and Comparative Example 3 that the role of PG in the technical solution comes from PA and GZ respectively, wherein,

[0103] The main role of PA in the technical solution is to reduce the burning area of ​​wood, 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 increase the limiting oxygen index of wood, reduce the combustion area, total heat release and total smoke release, thereby improving flame retardant properties.

[0105] The reason is,

[0106] The mechanism by which PA improves flame retardancy is that it contains a large number of phosphorus-containing groups, which can effectively promote the dehydration of wood into carbon, so that a dense carbon layer is formed on the wood surface to protect the wood matrix, thereby improving the ability of the carbon layer to isolate the heat during combustion and hinder the generated gas from rushing out, thereby reducing the combustion area, and reducing the maximum heat release rate, total heat release, and total smoke release;

[0107] The mechanism by which GZ improves flame retardancy is that it contains a large number of nitrogen-containing groups, which generate non-flammable gases such as nitrogen and ammonia when wood burns. The rushing out of these gases not only plays a physical "blowing out effect" to promote the extinguishing of the flame, but also dilutes the oxygen in the air, making it impossible for the flame to continue burning. As a result, the burning part of the wood is reduced, the limiting oxygen index is increased, the heat and smoke release are reduced, and the fire hazard is reduced.

[0108] Through reference example, comparative example 1, comparative example 2, comparative example 3, embodiment 1, can obtain the following conclusion:

[0109] 1. The flame retardant and smoke suppression properties of wood impregnated with flame retardant liquid are greatly improved compared with those of unimpregnated wood, and the fire growth index under real combustion conditions is also greatly reduced. The flame retardant liquid can effectively improve the flammable properties of wood and make it have high flame retardant and smoke suppression properties.

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

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

Claims

1. A smoke suppression and flame retardant liquid based on KH550, characterized in that: Ammonium dihydrogen phosphate ADP, phytic acid PA and guanidine GZ are used as main raw materials, and γ-aminopropyltriethoxysilane KH550 is used as coupling auxiliary agent.

2. The smoke suppressant and flame retardant liquid according to claim 1, characterized in that: The main function of the ADP is to provide phosphorus and nitrogen elements, and at the same time, it has the functions of promoting the dehydration of the substrate to form a protective carbon layer and forming a non-combustible gas to dilute the oxygen in the air to inhibit combustion; The main function of PA is to increase the phosphorus content and promote the formation of a dense protective carbon layer on the matrix; The main function of GZ is to increase the nitrogen content and improve the combustion suppression effect; The main function of KH550 is to increase the interaction between ADP, PA, GZ and the wood surface, thereby improving the flame retardant performance. At the same time, it provides silicon elements to form a highly stable Si-O structure during combustion, promoting a dense and stable protective carbon layer.

3. A method for preparing a smoke suppressant and flame retardant liquid based on KH550, characterized in that The following steps are involved: Step 1, preparation of 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, referred to as PG; Step 2, preparation of smoke suppressant and flame retardant liquid ADP / KH550 / PG. Under certain conditions, diammonium phosphate ADP and γ-aminopropyltriethoxysilane KH550 are simultaneously added to the PG obtained in step 1 to obtain solution C. After the addition is completed, under certain conditions, solution C is stirred to obtain a smoke suppressant and flame retardant liquid based on KH550, named ADP / KH550 / PG.

4. The preparation method according to claim 3, characterized in that: In the step 1, the mass ratio of GZ, PA and deionized water is 2:2:100; In the step 2, the mass ratio of ADP, KH550 and PG is 14:2:

104.

5. The preparation method according to claim 3, characterized in that: In the step 1, the conditions for dissolving GZ to prepare solution A are that the dissolution temperature is room temperature and the dissolution speed is 300-400 rpm; In step 1, the stirring reaction conditions of solution B are as follows: the stirring temperature is room temperature, the stirring speed is 300-400 rpm, and the stirring time is 0.5 h; In step 2, the conditions for adding ADP and KH550 to prepare solution C are that the addition temperature is room temperature and the stirring speed is 400-500 rpm; In the step 2, the stirring reaction conditions of solution C are as follows: the stirring temperature is room temperature, the stirring speed is 300-400 rpm, and the stirring time is 0.5 h.

6. A smoke suppression and flame retardant liquid based on KH550, characterized in that: When used as a wood flame retardant liquid, it has flame retardant properties. The wood impregnated with the flame retardant liquid passes the UL-94V-0 grade test in the UL-94 grade test; the residual carbon layer formed after the wood impregnated with the flame retardant liquid is burned is in a large-area continuous and dense state.

7. A smoke suppression and flame retardant liquid based on KH550, characterized in that: When used as a wood flame retardant, the limiting oxygen index of the wood impregnated with the flame retardant is 38.4±1% in a limiting oxygen index test.

8. A smoke suppression and flame retardant liquid based on KH550, characterized in that: When used as a wood flame retardant, the maximum heat release rate of the wood impregnated with the flame retardant in the cone calorimetry test is 41.31±2.51kW / m 2 The total heat release is 6.15±0.94MJ / m 2 The total smoke volume is 0.26±0.01m 2 , the fire growth index is 0.31±0.02kW / m 2 / s.

9. A smoke suppression and flame retardant liquid based on KH550, characterized in that: When used as a wood flame retardant, the wood impregnated with the flame retardant has a residual carbon content of 40.96±1wt.% at 800°C in a thermogravimetric test.

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