A flame-retardant fabric, its preparation method and application

Abstract

The present invention relates to the field of new material technologies, and discloses a flame-retardant fabric, a preparation method thereof and an application thereof. The method includes: (1) performing a first contact reaction on diethylenetriamine, vinylsilane and epoxy group-containing silane to obtain diethylenetriamine-silane; (2) performing a first dilution of the diethylenetriamine-silane in solvent I, adjusting the pH to obtain a diethylenetriamine-silane solution, immersing the fabric in the diethylenetriamine-silane to perform a first immersion to obtain a flame-retardant treated fabric I; (3) performing a second contact reaction on tetrakis(hydroxymethyl)phosphonium sulfate, urea and water to obtain a pre-polymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant; (4) immersing the flame-retardant treated fabric I in the pre-polymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant to perform a second immersion to obtain a flame-retardant fabric. The flame-retardant fabric prepared by the method provided by the present invention has excellent flame-retardant effect, the method is simple and efficient, and there is no need for gas to participate in the reaction, the cost is low, and it is suitable for mass production.

Description

Technical Field

[0001] The present invention relates to the technical field of new materials, and particularly relates to a flame-retardant fabric, a preparation method thereof and an application thereof. Background Art

[0002] A flame-retardant fabric is a textile material with special chemical treatment, having the ability to inhibit flame spread and reduce the fire risk. In many fields, such as construction, automotive, aerospace and personal protection, etc., the demand for flame-retardant fabrics is increasing day by day. The traditional preparation method of flame-retardant fabrics is covalent bond surface modification, usually using chemical flame retardants (such as Proban flame retardant) for post-treatment, which requires an ammonia atmosphere to assist the reaction. The treatment process is relatively complex, involving the control of multiple steps and parameters, such as ammonia concentration, treatment time and temperature, etc., and the release of toxic and harmful gases such as formaldehyde and ammonia and the treatment of chemical waste liquid during the production process require special treatment to ensure the minimum impact on the environment.

[0003] Patent CN202111485654.4 discloses the production process of reactive flame retardant THPO, achieving the preparation of high-efficiency flame retardants, but there are problems of complex process, associated harmful substances and general fabric applicability.

[0004] Therefore, it is of great significance to provide a simple and efficient method for preparing a flame-retardant fabric with high flame-retardant performance, which does not require gas to participate in the reaction, has low cost and is suitable for batch production. Summary of the Invention

[0005] The object of the present invention is to overcome the problems in the prior art that the process for preparing flame-retardant fabrics is complex, costly, has a narrow fabric application range and serious pollution.

[0006] To achieve the above object, the present invention provides a method for preparing a flame-retardant fabric, which method comprises:

[0007] (1) Mixing diethylenetriamine, vinyl silane and epoxy group-containing silane to carry out a first contact reaction to obtain diethylenetriamine-silane;

[0008] (2) Diluting the diethylenetriamine-silane in solvent I, adjusting the pH to 4-6 to obtain a diethylenetriamine-silane solution, and then immersing the fabric in the diethylenetriamine-silane for the first immersion for 10-20 min, and drying to obtain flame-retardant treated fabric I;

[0009] (3) At 85-95 °C, mixing tetrakis(hydroxymethyl)phosphonium sulfate, urea and water to carry out a second contact reaction to obtain a pre-polymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant;

[0010] (4) Immerse the flame-retardant treated fabric I in the pre-polymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant for a second immersion for 5 - 15 min, and obtain a flame-retardant fabric after drying.

[0011] The second aspect of the present invention provides a flame-retardant fabric prepared by the method described in the first aspect above.

[0012] The third aspect of the present invention provides the application of the flame-retardant fabric described in the second aspect above in the field of fire prevention and flame retardancy.

[0013] Compared with the prior art, the present invention has at least the following beneficial effects:

[0014] (1) In the present invention, a diethylenetriamine-silane two-dimensional functional layer is constructed on the surface of fabric fibers, and then the prepared organic nitrogen-phosphorus flame-retardant prepolymer is polymerized and grown on the surface of the two-dimensional functional layer to form a dense tetrakis(hydroxymethyl)phosphonium sulfate flame-retardant functional layer, which cooperates with other technical features to realize the post-treatment modification of flame retardancy of the fabric;

[0015] (2) The flame-retardant fabric prepared by the method of the present invention has significantly high flame-retardant performance, reduces the combustion reaction rate, and can effectively inhibit the spread of flames;

[0016] (3) The diethylenetriamine-silane / tetrakis(hydroxymethyl)phosphonium sulfate flame-retardant system used in the flame-retardant fabric prepared by the present invention is suitable for the immersion modification of most cellulose-containing fabrics, such as polyester / cotton blended fabrics, all-cotton fabrics, wool fabrics, silk fabrics, linen fabrics, etc.;

[0017] (4) The whole process of the flame-retardant fabric of the present invention is completed through impregnation and padding. The raw materials involve diethylenetriamine, silane, tetrakis(hydroxymethyl)phosphonium sulfate, and urea, all of which are widely sourced and low-cost. The whole preparation process does not require gas participation compared with traditional flame-retardant treatments such as Proban. The process flow is simple and efficient, and has good industrial application prospects. Description of the Drawings

[0018] Figure 1 is a physical diagram of the flame-retardant fabric prepared by the preferred embodiment of the present invention;

[0019] Figure 2 is a vertical combustion flame-retardant performance display diagram of the flame-retardant fabric prepared by the preferred embodiment of the present invention;

[0020] Figure 3 is a physical diagram of the flame-retardant fabric prepared in the comparative example of the present invention. Detailed Embodiments

[0021] The endpoints and any values disclosed in this text for ranges are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in this text.

[0022] As described above, the present invention provides a method for preparing a flame-retardant fabric, and the method includes:

[0023] (1) Mix diethylenetriamine, vinylsilane, and epoxy-group-containing silane to carry out a first contact reaction to obtain diethylenetriamine-silane;

[0024] (2) Dilute the diethylenetriamine-silane in Solvent I for the first time, adjust the pH to 4 - 6 to obtain a diethylenetriamine-silane solution, then immerse the fabric in the diethylenetriamine-silane for the first immersion for 10 - 20 min, and after drying, obtain flame-retardant treated fabric I;

[0025] (3) At 85 - 95 °C, mix tetrakis(hydroxymethyl)phosphonium sulfate, urea, and water to carry out a second contact reaction to obtain a pre-polymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant;

[0026] (4) Immerse the flame-retardant treated fabric I in the pre-polymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant for the second immersion for 5 - 15 min, and after drying, obtain a flame-retardant fabric.

[0027] Preferably, in step (1), the molar ratio of the amounts of the diethylenetriamine, the vinylsilane, and the epoxy-group-containing silane is 1:2 - 2.5:2 - 2.5.

[0028] Preferably, in step (2), the fabric is selected from at least one of cellulose-containing fabrics such as polyester / cotton blended fabrics, polyester fabrics, all-cotton fabrics, hemp fiber fabrics, wool fabrics, etc.

[0029] Preferably, in step (3), the molar ratio of the amounts of the tetrakis(hydroxymethyl)phosphonium sulfate, the urea, and the water is 1:2 - 3:38 - 40. The inventor has found that the flame-retardant performance of the flame-retardant fabric prepared under this preferred condition is better.

[0030] Preferably, the method of the present invention further includes that in step (3), before carrying out the second contact reaction, first configure a part of the water to form a tetrakis(hydroxymethyl)phosphonium sulfate aqueous solution with a concentration of 70 - 80 wt% of the tetrakis(hydroxymethyl)phosphonium sulfate, and then mix the tetrakis(hydroxymethyl)phosphonium sulfate aqueous solution, the urea, and the other part of the water to carry out the second contact reaction to obtain a pre-polymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant.

[0031] Preferably, in step (2), the weight ratio of the diethylenetriamine-silane to the solvent I is 20-30:100.

[0032] More preferably, in step (2), glacial acetic acid (anhydrous acetic acid) is used to adjust the pH of the diethylenetriamine-silane.

[0033] Preferably, the vinyl silane is vinyltrimethoxysilane and / or vinyltriethoxysilane.

[0034] Preferably, the epoxy group-containing silane is glycidoxypropyltrimethoxysilane and / or 3-glycidoxypropyltriethoxysilane.

[0035] Preferably, the conditions for the first dilution at least satisfy: the rotation speed is 250-400 rpm, the temperature is 22-28 °C, and the time is 5-10 min.

[0036] Preferably, in step (1), the first contact reaction is carried out under stirring conditions and at least satisfies: the rotation speed is 250-320 rpm, the time is 5-15 min, and the temperature is 22-28 °C.

[0037] According to a preferred embodiment, in step (3), the second contact reaction is carried out under stirring conditions and at least satisfies: the rotation speed is 250-320 rpm, and the time is 40-65 min.

[0038] According to a preferred embodiment, in step (4), before applying the pre-polymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant to the second soaking, the pre-polymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant is first second-diluted in solvent II to obtain a pre-polymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant solution, and then the second soaking is carried out, wherein the weight ratio of the pre-polymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant to the solvent II is 20-40:100.

[0039] Preferably, the second dilution is carried out under stirring conditions and at least satisfies: the rotation speed is 350-600 rpm, the temperature is 55-65 °C, and the time is 3-5 min.

[0040] Preferably, the solvent I is dichloromethane and / or an aqueous ethanol solution with a concentration of 60 vol%.

[0041] Preferably, the solvent II is water.

[0042] According to a preferred embodiment, in step (4), the temperature of the second soaking is 70 - 80 °C. The inventors found that in this preferred case, the flame retardant performance of the prepared flame retardant fabric can be improved.

[0043] Preferably, before the drying, the flame retardant treated fabric I after the second soaking is first sent to a calender for padding.

[0044] Preferably, the operation steps of the drying include: baking the flame retardant treated fabric I after the second soaking in a continuous baking oven at 130 - 150 °C for 3 - 8 min, washing with water for 30 - 45 s, and then drying in an oven at 65 - 75 °C for 120 - 150 min to obtain the flame retardant fabric.

[0045] As mentioned above, the second aspect of the present invention provides a flame retardant fabric prepared by the method described in the first aspect above.

[0046] As mentioned above, the third aspect of the present invention provides the application of the flame retardant fabric described in the second aspect above in the field of fire prevention and flame retardancy.

[0047] It should be noted that the present invention has no special requirements for the parameters of the padding, the equipment model of the stirring, and the size of the fabric, and conventional parameters in the industry can be selected.

[0048] The present invention is described in detail below through examples. Without special instructions, the raw materials used are all ordinary commercially available products.

[0049] Without special instructions, the "room temperature" or "normal temperature" mentioned in the present invention means a temperature of 25 ± 5 °C.

[0050] Fabric:

[0051] Fabric I: It is a polyester / cotton blended fabric, with a polyester content of 40 wt% and a cotton fiber content of 60 wt%;

[0052] Fabric II: It is a wool fabric, with a wool content of 40 wt% and a polyester content of 60 wt%;

[0053] Fabric III: It is a pure cotton fabric, with a cotton fiber content of 100 wt%;

[0054] Vinyl silane: It is vinyltrimethoxysilane, with a CAS number of 2768 - 02 - 7, purchased from Shanghai Merck Chemical Technology Co., Ltd., and the product number is M73370 - 100ML;

[0055] Epoxy group-containing silane: It is glycidoxypropyltrimethoxysilane, with a CAS number of 2530 - 83 - 8, purchased from Shin-Etsu of Japan, and the product number is KBM403;

[0056] Tetrakis(hydroxymethyl)phosphonium sulfate: CAS No. is 55566 - 30 - 8, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., with the product number R009056.

[0057] Example 1

[0058] This example is used to illustrate that the method for preparing flame - retardant fabrics provided by the present invention is carried out according to the following steps:

[0059] (1) At room temperature with a rotation speed of 300 rpm, diethylenetriamine, vinyltrimethoxysilane, and 48.4 mL of 3 - glycidoxypropyltrimethoxysilane were added to a container according to a molar ratio of 1:2.2:2.2 for the first contact reaction for 10 min to obtain diethylenetriamine - silane;

[0060] (2) At room temperature with a rotation speed of 300 rpm, dichloromethane (solvent I) was added to the diethylenetriamine - silane for the first dilution, and then glacial acetic acid was added dropwise to adjust the pH of the solution to 5 to obtain a diethylenetriamine - silane treatment solution; wherein, the weight ratio of diethylenetriamine - silane to dichloromethane is 30:100;

[0061] Then, the fabric (fabric I) was soaked in the above - mentioned diethylenetriamine - silane treatment solution for 20 min, taken out and dried in the air to obtain flame - retardant treated fabric I;

[0062] (3) In a magnetic stirrer at 90 °C with a rotation speed of 300 rpm, 15 mL of distilled water was used to prepare an aqueous solution of tetrakis(hydroxymethyl)phosphonium sulfate with a concentration of 70 wt%, and then the obtained aqueous solution of tetrakis(hydroxymethyl)phosphonium sulfate was mixed with urea and 45.24 mL of distilled water according to a molar ratio of 1:2:29.2 for the second contact reaction for 40 min to obtain a pre - polymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant;

[0063] (4) At room temperature with a rotation speed of 300 rpm, 30 g of the above - mentioned pre - polymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant was added to 170 g of distilled water (solvent II) for the second dilution for 5 min to obtain a pre - polymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant solution;

[0064] At 70 °C, the flame - retardant treated fabric I was soaked in the pre - polymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant solution for 10 min, then the soaked flame - retardant treated fabric I was sent to a rolling mill for padding, baked in a continuous baking oven at 140 °C for 6 min, and finally, washed with water for 30 s and dried in an oven at 70 °C for 120 min to obtain a flame - retardant fabric, named P1;

[0065] Figure 1, (a) shows a physical picture of P1, and it can be seen in the figure that the combination effect of the polyester / cotton blended fabric and the pre-polymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant is excellent;

[0066] Figure 2 , (a) shows the vertical burning flame retardant performance results of P1. It can be seen in the figure that the burned length of the fabric is short, it is not ignited within the ignition time, the smoldering time is 0 s, and the afterflame time is 0 s. According to the national standard GB / T 17591-2006, the flame retardant grade of P1 is B1-grade flame retardant protective clothing fabric.

[0067] Example 2

[0068] This example is used to illustrate that the method for preparing the flame retardant fabric provided by the present invention is carried out according to the following steps:

[0069] (1) At room temperature and a rotation speed of 280 rpm, diethylenetriamine, vinyltrimethoxysilane, and 48.4 mL of 3-glycidoxypropyltrimethoxysilane are added to a container according to a molar ratio of 1:2.2:2.2 for the first contact reaction for 10 min to obtain diethylenetriamine-silane;

[0070] (2) At room temperature and a rotation speed of 280 rpm, dichloromethane (solvent I) is added to the diethylenetriamine-silane for the first dilution, and then glacial acetic acid is added dropwise to adjust the pH of the solution to 5.5 to obtain a diethylenetriamine-silane treatment solution; wherein, the weight ratio of diethylenetriamine-silane to dichloromethane is 20:100;

[0071] Then the fabric (fabric II) is soaked in the above diethylenetriamine-silane treatment solution for 15 min, taken out and dried to obtain the flame retardant treated fabric I;

[0072] (3) In a magnetic stirrer at 90 °C and a rotation speed of 300 rpm, 17.5 mL of distilled water is used to configure the tetrakis(hydroxymethyl)phosphonium sulfate into a tetrakis(hydroxymethyl)phosphonium sulfate aqueous solution with a concentration of 65 wt%. Then, the obtained tetrakis(hydroxymethyl)phosphonium sulfate aqueous solution, urea, and 47.8 mL of distilled water are mixed according to a molar ratio of 1:2:30.9 for the second contact reaction for 40 min to obtain a pre-polymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant;

[0073] (4) At room temperature and a rotation speed of 280 rpm, 30 g of the above pre-polymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant is added to 180 g of distilled water (solvent II) for the second dilution for 5 min to obtain a pre-polymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant solution;

[0074] At 70 °C, the flame-retardant treated fabric I was soaked for a second time in a pre-polymerized solution of tetrakis(hydroxymethyl)phosphonium sulfate flame retardant for 10 min, and then the soaked flame-retardant treated fabric I was fed into a rolling mill for padding, baked in a continuous baking oven at 140 °C for 6 min, and finally washed with water for 30 s and dried in an oven at 70 °C for 130 min to obtain a flame-retardant fabric named P2;

[0075] Figure 1 , the physical picture of P2 is shown in (b), and it can be seen in the figure that the bonding effect between the wool fabric and the pre-polymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant is excellent;

[0076] Figure 2 , the vertical burning flame-retardant performance results of P1 are shown in (b). It can be seen in the figure that the burned length of the fabric is short, it is not ignited within the ignition time, the smoldering time is 0 s, and the afterflame time is 0 s. According to the national standard GB / T 17591-2006, the flame-retardant grade of P1 is B1 grade flame-retardant protective clothing fabric.

[0077] Example 3

[0078] This example was carried out in a similar manner to Example 1, except that the fabric used was Fabric III, and finally a flame-retardant fabric named P3 was obtained;

[0079] Figure 1 , the physical picture of P3 is shown in (c), and it can be seen in the figure that the bonding effect between the cotton fabric and the pre-polymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant is excellent.

[0080] Figure 2 , the vertical burning flame-retardant performance results of P3 are shown in (c). It can be seen in the figure that the burned length of the fabric is short, it is not ignited within the ignition time, the smoldering time is 0 s, and the afterflame time is 0 s. According to the national standard GB / T 17591-2006, the flame-retardant grade of P1 is B1 grade flame-retardant protective clothing fabric.

[0081] Example 4

[0082] This example was carried out in a similar manner to Example 1, except that the molar ratio of the amounts of tetrakis(hydroxymethyl)phosphonium sulfate, urea and water was 1:2:44, and finally a flame-retardant fabric named P4 was obtained.

[0083] Comparative Example 1

[0084] This comparative example was carried out in a similar manner to Example 1, except that the operations of steps (1) and (2) were not carried out, and step (3) was directly carried out. The specific operations of this comparative example include:

[0085] (a) In a magnetic stirrer at 90 °C with a rotation speed of 300 rpm, 15 mL of distilled water was used to prepare an aqueous solution of tetrakis(hydroxymethyl)phosphonium sulfate with a concentration of 70 wt%. Then, the obtained aqueous solution of tetrakis(hydroxymethyl)phosphonium sulfate was mixed with urea and 45.24 mL of distilled water in a molar ratio of 1:2:29.2 for a second contact reaction for 40 min to obtain a prepolymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant;

[0086] (b) At room temperature and a rotation speed of 300 rpm, 30 g of the above prepolymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant was added to 170 g of distilled water (solvent II) for a second dilution to obtain a prepolymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant solution;

[0087] At 70 °C, the flame-retardant-treated fabric I was secondarily immersed in the prepolymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant solution for 10 min, and then the immersed cotton fabric I was filled using a rolling mill and baked in a continuous baking machine at 140 °C for 6 min. Finally, after washing with water and drying in an oven at 70 °C, a flame-retardant fabric was obtained and named DP1;

[0088] Figure 3 A physical picture of DP1 is shown, and it can be seen in the figure that the combination effect between the all-cotton fabric in DP1 and the prepolymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant is not good.

[0089] Comparative Example 2

[0090] This comparative example was carried out using a method similar to that of Example 1, except that the operation in step (1) was not performed, and in step (2), diethylenetriamine was directly used instead of diethylenetriamine-silane for the first dilution. Specifically:

[0091] S1. At room temperature and a rotation speed of 300 rpm, 25 mL of dichloromethane (solvent I) was added to 10.7 mL of diethylenetriamine for the first dilution, and then glacial acetic acid was added dropwise to adjust the pH of the solution to 5 to obtain treatment liquid I;

[0092] S2. The fabric (fabric I) was first immersed in the above treatment liquid I for 20 min, taken out and dried in the air to obtain the flame-retardant-treated fabric I;

[0093] Then, the flame-retardant-treated fabric I was applied to the subsequent operations;

[0094] Finally, a flame-retardant fabric was obtained and named DP2.

[0095] Comparative Example 3

[0096] This comparative example was carried out using a method similar to that of Example 1, except that in step (3), the second contact reaction was carried out at room temperature;

[0097] Finally, a flame-retardant fabric was obtained and named DP3.

[0098] Comparative Example 4

[0099] This comparative example was carried out by a method similar to that of Example 1, except that in step (2), the time of the first immersion was 3 min.

[0100] Finally, a flame-retardant fabric was obtained and named DP4.

[0101] Comparative Example 5

[0102] This comparative example was carried out by a method similar to that of Example 1, except that in step (2), the pH value of the diethylenetriamine-silane solution was not adjusted. Specifically, the operation of step (2) included:

[0103] (2) At room temperature and a rotation speed of 300 rpm, dichloromethane (solvent I) was added to diethylenetriamine-silane for the first dilution to obtain a diethylenetriamine-silane treatment solution;

[0104] Then, the fabric (Fabric I) was immersed in the above diethylenetriamine-silane treatment solution for 20 min, taken out and dried to obtain a flame-retardant treated fabric I;

[0105] Finally, a flame-retardant fabric was obtained and named DP5.

[0106] Test Example 1

[0107] According to the standards of GB / T 17591-2006, GB / T 5454-1997 and GB / T 5455-2014, the limiting oxygen index, damage length, afterflame time, smoldering time, presence or absence of combustion drips, and flame-retardant performance grade of the flame-retardant fabrics and Fabric I obtained in the above example part were detected. The specific results are shown in Table 1, in which the test results of Fabric I were used as the control group.

[0108] Table 1:

[0109] ;

[0110] Note: In the table, "-" indicates poor flame-retardant performance and cannot reach the flame-retardant performance grades of B1 and B2.

[0111] Continued Table 1:

[0112] ;

[0113] Note: In the table, "-" indicates poor flame-retardant performance grade and cannot reach the flame-retardant performance grades of B1 and B2.

[0114] From the above results, it can be seen that the method provided by the present invention is simple and efficient, can be applied to various fabrics, does not require gas to participate in the reaction, is environmentally friendly, has low cost, is suitable for mass production, and the flame-retardant fabric prepared by this method has excellent flame-retardant effect.

[0115] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the technical concept scope of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A method for preparing a flame-retardant fabric, characterized in that, The method includes: (1) Mixing diethylenetriamine, vinyl silane, and epoxy group-containing silane to conduct a first contact reaction to obtain diethylenetriamine-silane; (2) Diluting the diethylenetriamine-silane in Solvent I for the first time, adjusting the pH to 4 - 6 to obtain a diethylenetriamine-silane solution, then immersing the fabric in the diethylenetriamine-silane for the first immersion for 10 - 20 min, and drying to obtain flame-retardant treated fabric I; (3) At 85 - 95 °C, mixing tetrakis(hydroxymethyl)phosphonium sulfate, urea, and water to conduct a second contact reaction to obtain a pre-polymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant; (4) Immersing the flame-retardant treated fabric I in the pre-polymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant for the second immersion for 5 - 15 min, and drying to obtain a flame-retardant fabric; The Solvent I is dichloromethane and / or an ethanol aqueous solution with a concentration of 60 vol%; The vinyl silane is vinyltrimethoxysilane and / or vinyltriethoxysilane; The epoxy group-containing silane is glycidoxypropyltrimethoxysilane and / or 3-glycidoxypropyltriethoxysilane.

2. The method according to claim 1, wherein In step (1), the molar ratio of the amounts of the diethylenetriamine, the vinyl silane, and the epoxy group-containing silane is 1:2 - 2.5:2 - 2.5; and / or In step (2), the fabric is selected from at least one of polyester / cotton blended fabric, all-cotton fabric, and wool fabric.

3. The method according to claim 1 or 2, wherein In step (3), the molar ratio of the amounts of the tetrakis(hydroxymethyl)phosphonium sulfate, the urea, and the water is 1:2 - 3:38 - 40.

4. The method according to claim 1 or 2, wherein In step (2), the weight ratio of the amounts of the diethylenetriamine-silane and the Solvent I is 20 - 30:

100.

5. The method according to claim 4, wherein In step (2), glacial acetic acid is used to adjust the pH of the diethylenetriamine-silane.

6. The method according to claim 1 or 2, wherein In step (1), the first contact reaction is carried out under stirring conditions, and at least satisfies: the rotation speed is 250 - 320 rpm, the time is 5 - 15 min, and the temperature is 22 - 28 °C; and / or In step (3), the second contact reaction is carried out under stirring conditions, and at least satisfies: the rotation speed is 250 - 320 rpm, and the time is 40 - 65 min.

7. The method according to claim 1 or 2, wherein In step (4), before applying the pre-polymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant to the second immersion, first dilute the pre-polymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant in Solvent II for the second time to obtain a pre-polymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant solution, and then conduct the second immersion, wherein the weight ratio of the amounts of the pre-polymerized tetrakis(hydroxymethyl)phosphonium sulfate flame retardant and the Solvent II is 20 - 40:100; Among them, the Solvent II is water.

8. The method according to claim 1 or 2, wherein In step (4), the temperature of the second immersion is 70 - 80 °C.

9. A flame-retardant fabric prepared by the method according to any one of claims 1 - 8.

10. Application of the flame-retardant fabric according to claim 9 in the field of fire prevention and flame retardancy.

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