Preparation Method of Durable Flame Retardant and Smoke Suppressant Cotton Fabric Based on Phosphorus / Nitrogen / Silicon Flame Retardant

Abstract

The present invention relates to a preparation method of a durable flame-retardant and smoke-suppressing cotton fabric based on a phosphorus / nitrogen / silicon flame retardant. First, diethylenetriamine pentamethylenephosphonic acid and tris(2,3-epoxypropyl) isocyanuric acid ester are dissolved in a solvent to obtain a mixed solution, and then (3-glycidoxypropyl)trimethoxysilane is added dropwise to the mixed solution at a rate of 0.5-1 mL / min to react to obtain a phosphorus / nitrogen / silicon flame retardant solution. Secondly, dicyandiamide is added to the phosphorus / nitrogen / silicon flame retardant solution, and then ammonia water is added to adjust the pH to 6-8 to obtain a flame-retardant finishing solution. Finally, the cotton fabric is immersed in the flame-retardant finishing solution and a durable flame-retardant and smoke-suppressing cotton fabric based on the phosphorus / nitrogen / silicon flame retardant is prepared by a padding-baking process. The product prepared by the method of the present invention has excellent flame-retardant durability and smoke-suppressing properties.

Description

Technical Field

[0001] The present invention belongs to the technical field of flame-retardant and smoke-suppressing cotton fabrics, and relates to a preparation method of a durable flame-retardant and smoke-suppressing cotton fabric based on a phosphorus / nitrogen / silicon flame retardant. Background Art

[0002] Cotton fabrics have been widely used in the fields of clothing, home textiles, medical and health, and industrial supplies due to their advantages of softness, comfort, good warmth retention, moisture absorption and breathability, easy dyeing and finishing, alkali resistance, and light resistance. However, due to the flammable nature of cotton fabrics, especially in high-risk industries such as metallurgy, fire protection, and chemical engineering, as well as in home textile products, the demand for flame-retardant treatment of cotton fabrics is increasing to improve safety and reduce fire risks. With the continuous rise of market demand, durable flame-retardant cotton fabrics have become an important research direction, and such products can still maintain their flame-retardant performance even after multiple washes.

[0003] In response to this demand, previous studies have made attempts. Literature 1 (Preparation of a durable and efficient phosphorus / nitrogen synergistic flame retardant and its application on cotton fabrics [J]. Journal of Textile Research, 2024, 45(7): 121-129.) prepared an intumescent phosphorus / nitrogen synergistic flame retardant (2-hydroxyethyl) phosphonamide ammonium salt (AHPA) using phosphorus pentoxide and ethanolamine as raw materials. The flame-retardant cotton fabric still had good flame-retardant performance after 50 washes, belonging to durable flame-retardant finishing. However, the smoke release performance of the flame-retardant cotton fabric increased significantly, resulting in a greatly increased fire hazard.

[0004] Literature 2 (Synthesis and flame retardant properties of a novel phosphorus-containing ammonium active group flame retardant for cotton [D]. Chongqing: Southwest University, 2017.) synthesized the flame retardant diethylenetriamine pentamethylene phosphonic acid ammonium (ADTPMPA) by reacting diethylenetriamine pentamethylene phosphonic acid as a raw material. The finished cotton fabric could withstand 30 washes and was a semi-durable flame-retardant fabric because the crosslinking degree between diethylenetriamine pentamethylene phosphonic acid ammonium and cotton fibers was limited, and its flame-retardant durability needed to be further improved; moreover, the smoke release of the flame-retardant cotton fabric also increased significantly because the char-forming property of the modified cotton fabric was still poor, and more smoke was generated through smoldering combustion.

[0005] It is worth noting that diethylenetriamine pentamethylene phosphonic acid has been widely used in many fields such as textile printing and dyeing due to its advantages of chemical stability, high temperature resistance, high solubility, and environmental friendliness. This compound meets the current environmental protection requirements due to its low toxicity and easy biodegradability, and the market demand continues to grow. Therefore, it is of great significance to develop durable flame-retardant functional cotton fabrics using diethylenetriamine pentamethylene phosphonic acid to improve the fire safety protection performance of cotton fabrics.

[0006] Therefore, it is of great significance to study a preparation method of a durable flame-retardant and smoke-suppressing cotton fabric based on phosphorus / nitrogen / silicon flame retardants to solve the problems existing in the prior art. Summary of the Invention

[0007] The object of the present invention is to solve the problems existing in the prior art and provide a preparation method of a durable flame-retardant and smoke-suppressing cotton fabric based on phosphorus / nitrogen / silicon flame retardants.

[0008] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] A preparation method of a durable flame-retardant and smoke-suppressing cotton fabric based on phosphorus / nitrogen / silicon flame retardants includes the following steps:

[0010] (1) Dissolve diethylenetriamine pentamethylenephosphonic acid and tris(2,3-epoxypropyl)isocyanurate in a solvent to obtain a mixed solution, and then drop (3-glycidoxypropyl)trimethoxysilane into the mixed solution at a rate of 0.5 - 1 mL / min to react to obtain a phosphorus / nitrogen / silicon flame retardant solution;

[0011] (2) Add dicyandiamide to the phosphorus / nitrogen / silicon flame retardant solution obtained in step (1), and then add ammonia water to adjust the pH to 6 - 8 to obtain a flame-retardant finishing solution; adjusting the pH to 6 - 8 makes part of the phosphate groups of diethylenetriamine pentamethylenephosphonic acid turn into ammonium phosphate groups, which is helpful for subsequent covalent grafting reactions;

[0012] (3) Immerse the cotton fabric in the flame-retardant finishing solution and obtain a durable flame-retardant and smoke-suppressing cotton fabric based on phosphorus / nitrogen / silicon flame retardants through a pad-dry-cure process.

[0013] As a preferred technical solution:

[0014] In the preparation method of the durable flame-retardant and smoke-suppressing cotton fabric based on phosphorus / nitrogen / silicon flame retardants as described above, in step (1), the solvent is a mixed solution of water and N,N-dimethylformamide, and the volume ratio of N,N-dimethylformamide in the mixed solution is 50 - 60%.

[0015] In the phosphorus / nitrogen / silicon flame retardant solution of step (1) in the preparation method of the durable flame-retardant and smoke-suppressing cotton fabric based on phosphorus / nitrogen / silicon flame retardants as described above, the content of diethylenetriamine pentamethylenephosphonic acid is 75 - 100 g / L, the content of tris(2,3-epoxypropyl)isocyanurate is 40 - 60 g / L, and the content of (3-glycidoxypropyl)trimethoxysilane is 20 - 40 g / L.

[0016] Diethylenetriamine pentamethylenephosphonic acid is the main flame retardant component. The higher its dosage, the better the flame retardant performance, but too high dosage will cause waste;

[0017] (3-Glycidylpropoxy)trimethoxysilane is soluble in N,N-dimethylformamide. Gradually adding (3-glycidylpropoxy)trimethoxysilane helps to promote the hydrolysis and condensation reaction that occurs after (3-glycidylpropoxy)trimethoxysilane contacts water, generating silica sol.

[0018] In the preparation method of the durable flame-retardant and smoke-suppressing cotton fabric based on phosphorus / nitrogen / silicon flame retardant as described above, in step (1), the reaction temperature is 75 - 85 °C, and the reaction time after adding the (3-glycidylpropoxy)trimethoxysilane solution dropwise is 2 - 3 h.

[0019] In the preparation method of the durable flame-retardant and smoke-suppressing cotton fabric based on phosphorus / nitrogen / silicon flame retardant as described above, the content of dicyandiamide in the flame-retardant finishing liquor in step (2) is 30 - 50 g / L.

[0020] In the preparation method of the durable flame-retardant and smoke-suppressing cotton fabric based on phosphorus / nitrogen / silicon flame retardant as described above, the pad-bake process in step (3) is specifically as follows: The two-dip two-roll method is adopted, and the liquor pickup rate is 90 - 110%; the pre-baking temperature is 75 - 85 °C, and the time is 2 - 3 min; the baking temperature is 165 - 175 °C, and the time is 2 - 3 min.

[0021] In the preparation method of the durable flame-retardant and smoke-suppressing cotton fabric based on phosphorus / nitrogen / silicon flame retardant as described above, the limiting oxygen index of the durable flame-retardant and smoke-suppressing cotton fabric based on phosphorus / nitrogen / silicon flame retardant is not less than 31.0%, the damage length is not more than 8.7 cm, and the total smoke release amount is not more than 0.10 m 2 , and after 50 washes, the damage length is still not more than 14.0 cm (the limiting oxygen index of the unmodified cotton fabric is 18.2%, the damage length is 30 cm, and the total smoke release amount is 0.15 m 2 )

[0022] The principle of the present invention is:

[0023] The phosphate group of diethylenetriamine pentamethylene phosphonic acid can undergo an esterification crosslinking reaction with the hydroxyl groups of cotton fibers under the catalysis of dicyandiamide, thereby grafting the phosphorus-containing flame-retardant group onto the cotton fibers. However, the degree of this reaction is limited, it is difficult to graft a sufficient amount of phosphorus-containing flame retardant onto the cotton fabric, it is difficult to provide durable flame-retardant performance, and the phosphorus-containing flame retardant alone causes an increase in the smoke release of the cotton fabric, increasing the fire hazard.

[0024] In the present invention, tris(2,3-epoxypropyl)isocyanurate contains three epoxy groups, which can undergo ring-opening addition reaction with the phosphate groups of diethylenetriamine pentamethylenephosphonic acid. The silanol groups formed by the hydrolysis of (3-glycidoxypropyl)trimethoxysilane undergo hydrolysis condensation reaction in aqueous solution to form a network-like silica sol. Moreover, the epoxy groups and silanol groups of (3-glycidoxypropyl)trimethoxysilane can react with the phosphate groups of diethylenetriamine pentamethylenephosphonic acid after hydrolysis. Therefore, a new network-like phosphorus / nitrogen / silicon flame retardant is formed among the silicon-containing network, diethylenetriamine pentamethylenephosphonic acid, and tris(2,3-epoxypropyl)isocyanurate;

[0025] As Figure 1 shown, under the catalysis of dicyandiamide, the phosphate groups in the network-like phosphorus / nitrogen / silicon flame retardant can undergo esterification cross-linking reaction with the hydroxyl groups of cotton fibers, and the epoxy groups of tris(2,3-epoxypropyl)isocyanurate in the network-like phosphorus / nitrogen / silicon flame retardant can also undergo esterification cross-linking reaction with the hydroxyl groups of cotton fibers. Therefore, the network-like phosphorus / nitrogen / silicon flame retardant can react with cotton fibers through two covalent bonds. Compared with the binding of a single phosphate covalent bond, the cross-linking degree and grafting amount of the cross-linking reaction described in the present invention are high, which helps to further improve the wash fastness;

[0026] In addition, the phosphate groups in the network-like phosphorus / nitrogen / silicon flame retardant act as acid sources, the nitrogen-containing groups of tris(2,3-epoxypropyl)isocyanurate act as gas sources, and the polycyclic structure of tris(2,3-epoxypropyl)isocyanurate acts as a carbon source, which organically combines to construct an intumescent flame retardant system with high flame retardancy efficiency. The silicon-containing flame retardant groups help to further improve the flame retardancy performance and have the ability to inhibit smoke release. Therefore, the cotton fabric modified by the coating has excellent flame retardancy and smoke suppression performance.

[0027] Beneficial effects:

[0028] (1) The preparation method of a durable flame retardant and smoke suppressing cotton fabric based on a phosphorus / nitrogen / silicon flame retardant according to the present invention forms a network-like phosphorus / nitrogen / silicon flame retardant through the reaction of tris(2,3-epoxypropyl)isocyanurate, (3-glycidoxypropyl)trimethoxysilane, and diethylenetriamine pentamethylenephosphonic acid. This flame retardant undergoes high cross-linking with cotton fibers under the catalysis of dicyandiamide, improving the wash fastness;

[0029] (2) The preparation method of a durable flame-retardant and smoke-suppressing cotton fabric based on a phosphorus / nitrogen / silicon flame retardant. In the network-like phosphorus / nitrogen / silicon flame retardant, phosphate groups act as the acid source, nitrogen-containing groups of tris(2,3-epoxypropyl)isocyanurate act as the gas source, and the polycyclic structure of tris(2,3-epoxypropyl)isocyanurate acts as the carbon source. They are organically combined to construct an intumescent flame-retardant system with high flame-retardant efficiency. The silicon-containing flame-retardant groups help to further improve the flame-retardant performance and have the ability to suppress smoke release. Therefore, the durable flame-retardant and smoke-suppressing cotton fabric has excellent flame-retardant and smoke-suppressing properties. Description of the Drawings

[0030] Figure 1 It is a schematic diagram of the crosslinking mechanism between the network-like phosphorus / nitrogen / silicon flame retardant and the cotton fabric. Detailed Embodiments

[0031] The following further elaborates the present invention in combination with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0032] The test methods for the performance indicators in the examples and comparative examples of the present invention are as follows:

[0033] Limiting oxygen index: Tested and characterized with reference to the standard of GB / T 5454-1997 "Textiles - Burning performance - Oxygen index method".

[0034] Damage length: Determined with reference to the standard of GB / T 5455-2014 "Textiles - Burning performance - Determination of damage length, afterflame and afterglow times in the vertical direction".

[0035] Total smoke release: Tested and characterized for the total smoke release of the sample using a VOUCH 6810 cone calorimeter with reference to the ISO 5660-1 standard.

[0036] Damage length after 50 washes: First, wash the fabric 50 times with reference to the standard of AATCC 61-2013 "Accelerated test for colorfastness to laundering, home and commercial". Then, test the damage length of the fabric with reference to the standard of GB / T 5455-2014 "Textiles - Burning performance - Determination of damage length, afterflame and afterglow times in the vertical direction".

[0037] Example 1

[0038] The preparation method of a durable flame-retardant and smoke-suppressing cotton fabric based on a phosphorus / nitrogen / silicon flame retardant is as follows:

[0039] (1) Dissolve diethylenetriamine pentamethylenephosphonic acid and tris(2,3-epoxypropyl)isocyanurate in a solvent to obtain a mixed solution, and then drop (3-glycidoxypropyl)trimethoxysilane into the mixed solution at a rate of 0.5 mL / min, and react at a temperature of 85 °C for 3 h to obtain a phosphorus / nitrogen / silicon flame retardant solution;

[0040] Among them, the solvent is a mixed solution of water and N,N-dimethylformamide, and the volume ratio of N,N-dimethylformamide in the mixed solution is 50%; in the phosphorus / nitrogen / silicon flame retardant solution, the content of diethylenetriamine pentamethylenephosphonic acid is 75 g / L, the content of tris(2,3-epoxypropyl)isocyanurate is 40 g / L, and the content of (3-glycidoxypropyl)trimethoxysilane is 20 g / L;

[0041] (2) Add dicyandiamide to the phosphorus / nitrogen / silicon flame retardant solution obtained in step (1), and then add ammonia water to adjust the pH to 6 to obtain a flame retardant finishing solution with a dicyandiamide content of 30 g / L;

[0042] (3) Immerse the cotton fabric in the flame retardant finishing solution, carry out two-dip and two-roll treatment, control the pick-up rate to be 90%, and then carry out baking treatment to obtain a durable flame retardant and smoke suppressant cotton fabric based on the phosphorus / nitrogen / silicon flame retardant;

[0043] The specific baking process is: the pre-baking temperature is 85 °C and the time is 2 min; the curing temperature is 165 °C and the time is 3 min.

[0044] The limiting oxygen index of the finally obtained durable flame retardant and smoke suppressant cotton fabric based on the phosphorus / nitrogen / silicon flame retardant is 31%, the damage length is 8.7 cm, and the total smoke release is 0.1 m 2 , and the damage length is 14 cm after 50 washes.

[0045] Comparative Example 1

[0046] A method for preparing a modified cotton fabric is basically the same as that in Example 1, except that tris(2,3-epoxypropyl)isocyanurate is not added in step (1).

[0047] The limiting oxygen index of the finally obtained modified cotton fabric is 29.9%, the damage length is 9.8 cm, and the total smoke release is 0.12 m 2 and the damage length is 30 cm after 40 washes.

[0048] Comparing Comparative Example 1 with Example 1, it can be found that when tris(2,3-epoxypropyl)isocyanurate is not added, the flame retardancy, smoke suppression performance, and wash fastness of the modified cotton fabric decrease. This is because tris(2,3-epoxypropyl)isocyanurate plays a cross-linking role, and its polycyclic structure acts as a carbon source. When tris(2,3-epoxypropyl)isocyanurate is not added, first, the flame retardancy becomes poor due to the inability to achieve a synergistic flame retardant effect. Second, cross-linking cannot occur, resulting in easy loss during the washing process and a decrease in wash fastness.

[0049] Comparative Example 2

[0050] A preparation method of a durable flame-retardant and smoke-suppressing cotton fabric is basically the same as that of Example 1, except that (3-glycidylpropoxy)trimethoxysilane is not added.

[0051] The limiting oxygen index of the finally prepared durable flame-retardant and smoke-suppressing cotton fabric is 29.1%, the char length is 10.3 cm, and the total smoke release is 0.17 m 2 , and the char length is 30 cm after 40 washes.

[0052] Comparing Comparative Example 2 with Example 1, it can be found that when (3-glycidylpropoxy)trimethoxysilane is not added, the flame retardancy, smoke suppression performance, and wash fastness of the durable flame-retardant and smoke-suppressing cotton fabric decrease. This is because the silicon-containing flame retardant group helps to further improve the flame retardancy and has the ability to suppress smoke release.

[0053] Example 2

[0054] A preparation method of a durable flame-retardant and smoke-suppressing cotton fabric based on a phosphorus / nitrogen / silicon flame retardant is as follows:

[0055] (1) Dissolve diethylenetriamine pentamethylenephosphonic acid and tris(2,3-epoxypropyl)isocyanurate in a solvent to obtain a mixed solution, and then add (3-glycidylpropoxy)trimethoxysilane to the mixed solution at a rate of 0.7 mL / min and react at a temperature of 80 °C for 2.85 h to obtain a phosphorus / nitrogen / silicon flame retardant solution;

[0056] Among them, the solvent is a mixed solution of water and N,N-dimethylformamide, and the volume ratio of N,N-dimethylformamide in the mixed solution is 55%; in the phosphorus / nitrogen / silicon flame retardant solution, the content of diethylenetriamine pentamethylenephosphonic acid is 85 g / L, the content of tris(2,3-epoxypropyl)isocyanurate is 45 g / L, and the content of (3-glycidylpropoxy)trimethoxysilane is 25 g / L;

[0057] (2) Add dicyandiamide to the phosphorus / nitrogen / silicon flame retardant solution obtained in step (1), and then add ammonia water to adjust the pH to 6.5 to obtain a flame retardant finishing solution with a dicyandiamide content of 35 g / L;

[0058] (3) Immerse the cotton fabric in the flame retardant finishing solution, carry out two-bath two-roll treatment, control the liquor pickup rate to 95%, and then carry out baking treatment to obtain a durable flame retardant and smoke suppressing cotton fabric based on phosphorus / nitrogen / silicon flame retardant;

[0059] The baking process is specifically as follows: the pre-baking temperature is 80 °C and the time is 2.5 min; the curing temperature is 168 °C and the time is 2.75 min.

[0060] The limiting oxygen index of the finally obtained durable flame retardant and smoke suppressing cotton fabric based on phosphorus / nitrogen / silicon flame retardant is 31.6%, the damage length is 8.3 cm, and the total smoke release is 0.08 m 2 , and the damage length is 13.5 cm after 50 washes.

[0061] Example 3

[0062] A preparation method of a durable flame retardant and smoke suppressing cotton fabric based on phosphorus / nitrogen / silicon flame retardant, the specific steps are as follows:

[0063] (1) Dissolve diethylenetriamine pentamethylenephosphonic acid and tris(2,3-epoxypropyl)isocyanurate in a solvent to obtain a mixed solution, and then drop (3-glycidoxypropyl)trimethoxysilane into the mixed solution at a rate of 0.9 mL / min, and react at a temperature of 78 °C for 2.5 h to obtain a phosphorus / nitrogen / silicon flame retardant solution;

[0064] Among them, the solvent is a mixed solution of water and N,N-dimethylformamide, and the volume ratio of N,N-dimethylformamide in the mixed solution is 58%; in the phosphorus / nitrogen / silicon flame retardant solution, the content of diethylenetriamine pentamethylenephosphonic acid is 90 g / L, the content of tris(2,3-epoxypropyl)isocyanurate is 50 g / L, and the content of (3-glycidoxypropyl)trimethoxysilane is 30 g / L;

[0065] (2) Add dicyandiamide to the phosphorus / nitrogen / silicon flame retardant solution obtained in step (1), and then add ammonia water to adjust the pH to 7 to obtain a flame retardant finishing solution with a dicyandiamide content of 40 g / L;

[0066] (3) Immerse the cotton fabric in the flame retardant finishing solution, carry out two-bath two-roll treatment, control the liquor pickup rate to 100%, and then carry out baking treatment to obtain a durable flame retardant and smoke suppressing cotton fabric based on phosphorus / nitrogen / silicon flame retardant;

[0067] The baking process is specifically as follows: the pre-baking temperature is 78 °C and the time is 2.85 min; the curing temperature is 170 °C and the time is 2.5 min.

[0068] The limiting oxygen index of the finally obtained durable flame-retardant and smoke-suppressing cotton fabric based on phosphorus / nitrogen / silicon flame retardant is 32.1%, the char length is 8 cm, and the total smoke release is 0.07 m 2 , and the char length is 13.2 cm after 50 washes.

[0069] Example 4

[0070] A preparation method of a durable flame-retardant and smoke-suppressing cotton fabric based on phosphorus / nitrogen / silicon flame retardant, the specific steps are as follows:

[0071] (1) Dissolve diethylenetriamine pentamethylenephosphonic acid and tris(2,3-epoxypropyl) isocyanurate in a solvent to obtain a mixed solution, and then drop (3-glycidoxypropyl)trimethoxysilane into the mixed solution at a rate of 1 mL / min, and react at a temperature of 75 °C for 2 h to obtain a phosphorus / nitrogen / silicon flame retardant solution;

[0072] Among them, the solvent is a mixed solution of water and N,N-dimethylformamide, and the volume ratio of N,N-dimethylformamide in the mixed solution is 60%; in the phosphorus / nitrogen / silicon flame retardant solution, the content of diethylenetriamine pentamethylenephosphonic acid is 100 g / L, the content of tris(2,3-epoxypropyl) isocyanurate is 60 g / L, and the content of (3-glycidoxypropyl)trimethoxysilane is 40 g / L;

[0073] (2) Add dicyandiamide to the phosphorus / nitrogen / silicon flame retardant solution obtained in step (1), and then add ammonia water to adjust the pH to 8 to obtain a flame retardant finishing solution with a dicyandiamide content of 50 g / L;

[0074] (3) Immerse the cotton fabric in the flame retardant finishing solution, perform two-dip and two-roll treatment, control the liquor ratio to 110%, and then perform baking treatment to obtain a durable flame-retardant and smoke-suppressing cotton fabric based on phosphorus / nitrogen / silicon flame retardant;

[0075] The baking process is specifically: the pre-baking temperature is 75 °C and the time is 3 min; the curing temperature is 175 °C and the time is 2 min.

[0076] The limiting oxygen index of the finally obtained durable flame-retardant and smoke-suppressing cotton fabric based on phosphorus / nitrogen / silicon flame retardant is 32.5%, the char length is 7.8 cm, and the total smoke release is 0.06 m 2 , and the char length is 13 cm after 50 washes.

Claims

1. A method for preparing a durable flame retardant and smoke-suppressing cotton fabric based on phosphorus / nitrogen / silicon flame retardants, characterized in that The steps include: (1) dissolving diethylenetriamine penta (methylene phosphonic acid) and tri (2,3-epoxypropyl) isocyanurate in a solvent to obtain a mixed solution, and then adding (3-glycidyl propoxy) trimethoxy silane dropwise to the mixed solution at a rate of 0.5 to 1 mL / min to react to obtain a network phosphorus / nitrogen / silicon flame retardant solution; (2) adding dicyandiamide to the network phosphorus / nitrogen / silicon flame retardant solution obtained in step (1), and then adding ammonia water to adjust the pH to 6-8 to obtain a flame retardant finishing solution; (3) immersing the cotton fabric in a flame retardant finishing liquid, and preparing a durable flame retardant and smoke suppression cotton fabric based on phosphorus / nitrogen / silicon flame retardant through a rolling and baking process; The limiting oxygen index of the durable flame retardant and smoke suppression cotton fabric based on phosphorus / nitrogen / silicon flame retardants is not less than 31.0%, the damaged length is not higher than 8.7cm, and the total amount of smoke release is not higher than 0.10m 2 After 50 washes, the damaged length is still no more than 14.0cm.

2. The method for preparing a durable flame retardant and smoke suppressant cotton fabric based on phosphorus / nitrogen / silicon flame retardants according to claim 1, characterized in that: In step (1), the solvent is a mixture of water and N,N-dimethylformamide, and the volume proportion of N,N-dimethylformamide in the mixture is 50-60%.

3. The method for preparing a durable flame retardant and smoke suppressant cotton fabric based on phosphorus / nitrogen / silicon flame retardants according to claim 1, characterized in that: In the network phosphorus / nitrogen / silicon flame retardant solution of step (1), the content of diethylenetriaminepenta(methylenephosphonic acid) is 75-100 g / L, the content of tri(2,3-epoxypropyl)isocyanurate is 40-60 g / L, and the content of (3-glycidylpropoxy)trimethoxysilane is 20-40 g / L.

4. The method for preparing a durable flame retardant and smoke suppressant cotton fabric based on phosphorus / nitrogen / silicon flame retardants according to claim 1, characterized in that: In step (1), the reaction temperature is 75-85° C., and the reaction time after the (3-glycidylpropoxy)trimethoxysilane solution is added dropwise is 2-3 hours.

5. The method for preparing a durable flame retardant and smoke suppressant cotton fabric based on phosphorus / nitrogen / silicon flame retardants according to claim 1, characterized in that: The content of dicyandiamide in the flame retardant finishing liquid of step (2) is 30-50 g / L.

6. The method for preparing a durable flame retardant and smoke suppressant cotton fabric based on phosphorus / nitrogen / silicon flame retardants according to claim 1, characterized in that: The rolling and baking process in step (3) is specifically as follows: a double-immersion and double-rolling method is adopted, with a rolling rate of 90-110%; a pre-baking temperature of 75-85° C. and a time of 2-3 minutes; and a baking temperature of 165-175° C. and a time of 2-3 minutes.

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