Preparation method of durable flame-retardant smoke-suppressing brocade / cotton blended fabric

Abstract

The invention relates to a preparation method of a durable flame-retardant smoke-suppressing brocade / cotton blended fabric, which comprises the following steps: adding diethylenetriaminepenta (methylene phosphonic acid) into water, adding ammonia water to adjust the pH value to 5-6 to obtain a solution A, dropwise adding an ethanol solution of tetraethyl orthosilicate into the solution A, reacting, and adding dicyandiamide to obtain a solution containing an anionic phosphorus / nitrogen / silicon flame retardant; then immersing the brocade / cotton blended fabric into a solution containing an anionic phosphorus / nitrogen / silicon flame retardant, and carrying out padding and baking treatment; immersing the treated brocade / cotton blended fabric into a polyacrylamide solution, and carrying out padding and drying treatment; and finally, repeating the process of padding the solution containing the anionic phosphorus / nitrogen / silicon flame retardant and the polyacrylamide solution for 2-3 times to prepare the durable flame-retardant smoke-suppressing brocade / cotton blended fabric. The product prepared by the method disclosed by the invention has excellent flame-retardant smoke suppression performance and washing resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of flame-retardant nylon / cotton blended fabrics and relates to a method for preparing a durable flame-retardant and smoke-suppressing nylon / cotton blended fabric. Background Art

[0002] Nylon / cotton blended fabrics not only have the breathability and comfort of cotton fibers, but also have the advantages of high strength and wear resistance of nylon fibers, so they have a wide range of application prospects. However, due to the "wick effect" when burning, nylon / cotton blended fabrics are extremely flammable, so their application is limited. The difficulty of durable flame retardant finishing of nylon / cotton blended fabrics is much more difficult than that of pure cotton and pure nylon fabrics. It is not possible to achieve flame retardant effects or long-lasting flame retardant effects by mixing cotton fabric durable flame retardant finishing agents and nylon durable flame retardant finishing agents.

[0003] For example, Reference 1 (Study on Flame Retardant and Flame Retardant Water Repellent Composite Finishing of 88 / 12 Cotton and Nylon Blended Fabrics [D]. Donghua University, 2016.) compounded four phosphorus-nitrogen composite flame retardants and studied the durable flame retardant finishing process of 88 / 12 cotton and nylon blended fabrics; however, the amount of flame retardant used was very high, and N-hydroxymethyl reactive flame retardant and resin cross-linking agent were used, which resulted in the potential release of formaldehyde from the modified fabric.

[0004] Chinese invention patent CN116516679A discloses a durable flame retardant and drip-proof coating nylon 6 fabric and its preparation method, wherein polyacrylamide, terephthalaldehyde and DOPO are dissolved in a mixed solution of ethanol and water for reaction to obtain modified polyacrylamide; the modified polyacrylamide is dissolved in a solvent, and the nylon 6 fabric is immersed in the solvent, and the durable flame retardant and drip-proof coating nylon 6 fabric is prepared by a padding-baking process. However, it is difficult to flame retard nylon / cotton blended fabrics. It is difficult to improve the flame retardant properties of nylon / cotton blended fabrics only through the gas phase flame retardant mechanism of DOPO flame retardant, and it is difficult to provide lasting flame retardant properties only by relying on the film-forming property of modified polyacrylamide on the fabric surface.

[0005] Therefore, it is of great significance to study a method for preparing a durable flame retardant and smoke-suppressing nylon / cotton blended fabric to solve the problems existing in the prior art. Summary of the invention

[0006] The purpose of the present invention is to solve the problems existing in the prior art and provide a method for preparing a durable flame retardant and smoke suppressing nylon / cotton blended fabric.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] A method for preparing a durable flame-retardant and smoke-suppressing nylon / cotton blended fabric comprises the following steps:

[0009] (1) Diethylenetriaminepenta(methylenephosphonic acid) is added to water, and ammonia water is added to adjust the pH value to 5-6 (so that part of the phosphate groups of diethylenetriaminepenta(methylenephosphonic acid) is converted into ammonium phosphate groups, which is helpful for tetraethyl orthosilicate to generate silica sol and is helpful for the subsequent covalent bond grafting reaction), to obtain solution A, and then tetraethyl orthosilicate ethanol solution is added dropwise to solution A at a rate of 0.5-1 mL / min, and dicyandiamide is added after the reaction to obtain a solution containing anionic phosphorus / nitrogen / silicon flame retardant; tetraethyl orthosilicate is easily soluble in ethanol solution, and gradually adding the ethanol solution of tetraethyl orthosilicate is helpful to promote the hydrolysis condensation reaction of tetraethyl orthosilicate after contact with water to generate silica sol;

[0010] (2) immersing the nylon / cotton blended fabric into the solution containing the anionic phosphorus / nitrogen / silicon flame retardant obtained in step (1), and performing padding and baking treatments;

[0011] (3) immersing the nylon / cotton blended fabric treated in step (2) into a polyacrylamide solution, and performing padding and drying treatments;

[0012] (4) Step (2) and step (3) are repeated 2 to 3 times to obtain a durable flame retardant and smoke suppressing nylon / cotton blended fabric.

[0013] As the preferred technical solution:

[0014] The method for preparing a durable flame retardant and smoke-suppressing nylon / cotton blended fabric as described above, in step (1), based on a solution containing anionic phosphorus / nitrogen / silicon flame retardants, the amount of diethylenetriaminepenta(methylenephosphonic acid) is 40-60 g / L, diethylenetriaminepenta(methylenephosphonic acid) is the main flame retardant component, and the higher the amount used, the better the flame retardant performance, but too high an amount is wasteful, the amount of tetraethyl orthosilicate used is 10-20 g / L, and the amount of dicyandiamide used is 20-30 g / L.

[0015] In the method for preparing a durable flame retardant and smoke suppressant nylon / cotton blended fabric as described above, in step (1) the ethanol solution of tetraethyl orthosilicate has a mass ratio of tetraethyl orthosilicate to ethanol of 1-2:1.

[0016] In the method for preparing a durable flame retardant and smoke suppressant nylon / cotton blended fabric as described above, the reaction temperature in step (1) is 50-60° C., and the reaction time after the ethanol solution of tetraethyl orthosilicate is added is 2-3 hours.

[0017] In the method for preparing a durable flame retardant and smoke suppressant nylon / cotton blended fabric as described above, the impregnation and rolling in step (2) is double impregnation and double rolling, and the rolling rate is 90-110%.

[0018] In the method for preparing a durable flame retardant and smoke suppressant nylon / cotton blended fabric as described above, the baking process parameters in step (2) are: pre-baking temperature of 70-90°C, pre-baking time of 2-3 min, baking temperature of 160-170°C, and baking time of 3-4 min; a higher baking temperature helps to promote the covalent bond grafting reaction between the phosphate group of diethylenetriaminepenta(methylenephosphonic acid) in solution A and the hydroxyl group of cotton fiber, but if the baking temperature is too high, the physical properties of the fabric will be greatly damaged.

[0019] In the method for preparing a durable flame retardant and smoke suppressant nylon / cotton blended fabric as described above, the concentration of the polyacrylamide solution in step (3) is 10-20 g / L.

[0020] In the method for preparing a durable flame retardant and smoke suppressant nylon / cotton blended fabric as described above, the dipping and rolling in step (3) is performed by double dipping and double rolling, and the rolling rate is 90-110%.

[0021] In the method for preparing a durable flame retardant and smoke suppressant nylon / cotton blended fabric as described above, the drying temperature in step (3) is 70-90° C. and the drying time is 2-3 min.

[0022] A method for preparing a durable flame retardant and smoke-suppressing nylon / cotton blended fabric as described in any of the above items, wherein the limiting oxygen index of the durable flame retardant and smoke-suppressing nylon / cotton blended fabric is not less than 30.5%, the damaged length is not higher than 9.2 cm, and the total amount of smoke released is not higher than 0.37 m 2 After 40 washes, the damaged length is still no more than 14.7cm, meeting the B1 standard (the damaged length of unmodified nylon / cotton blended fabric is 30cm, the limiting oxygen index is 20.3%, and the total smoke release is 0.65m 2 ).

[0023] The principle of the present invention is:

[0024] The phosphate group of diethylenetriamine penta(methylenephosphonic acid) can undergo an esterification cross-linking reaction with the hydroxyl group of cotton fiber under the catalysis of dicyandiamide, thereby grafting the phosphorus-containing flame retardant group onto the cotton fiber. However, the cotton fiber component content in nylon / cotton blended fabrics is limited, and it is difficult to graft a sufficient amount of phosphorus-containing flame retardant onto the nylon / cotton blended fabric, and it is impossible to provide lasting flame retardant properties. In addition, the phosphorus-containing flame retardant alone causes the nylon / cotton blended fabric to release more smoke, thereby increasing the fire hazard.

[0025] In the present invention, the silanol groups formed by hydrolysis of the siloxane structure of tetraethyl orthosilicate undergo hydrolysis and condensation in an aqueous solution to generate a network-like silica sol, and the silanol groups can react with the phosphate radical of diethylenetriaminepenta(methylenephosphonic acid) after hydrolysis, so that an anionic phosphorus / nitrogen / silicon flame retardant is formed between the silicon-containing network and ammonium diethylenetriaminepenta(methylenephosphonic acid);

[0026] like Figure 1As shown, under the catalysis of dicyandiamide, the phosphate in the anionic phosphorus / nitrogen / silicon flame retardant can undergo esterification cross-linking reaction with the hydroxyl group of the cotton fiber; polyacrylamide is a cationic polymer, which can produce ionic bonds with the anionic phosphorus / nitrogen / silicon flame retardant, and polyacrylamide has good film-forming properties, and its amide structure has good affinity with the amide structure of nylon fiber, so the polyacrylamide film can be tightly combined with the nylon / cotton blended fabric; therefore, the anionic phosphorus / nitrogen / silicon flame retardant and polyacrylamide are deposited on the nylon / cotton blended fabric through ionic bonds, and are combined with the nylon / cotton blended fabric through covalent bonds and supramolecular forces, thereby providing durable flame retardant properties;

[0027] In addition, the phosphoric acid in the anionic phosphorus / nitrogen / silicon flame retardant, the amide structure of polyacrylamide and the silicon-containing flame retardant group improve the flame retardant properties of nylon / cotton blended fabrics through a synergistic flame retardant effect. The flame retardant efficiency is high, and the silicon-containing flame retardant group has the ability to inhibit the release of smoke. Therefore, the finished nylon / cotton blended fabric has excellent flame retardant and smoke suppression properties.

[0028] Beneficial effects:

[0029] (1) A method for preparing a durable flame retardant and smoke-suppressing nylon / cotton blended fabric of the present invention, wherein the silanol groups formed by hydrolysis of the siloxane structure of tetraethyl orthosilicate undergo hydrolysis and condensation in an aqueous solution to generate a network-like silica sol, and the silanol groups can react with the phosphate groups of diethylenetriaminepenta(methylenephosphonic acid) after hydrolysis, thereby forming an anionic phosphorus / nitrogen / silicon flame retardant between the silicon-containing network and ammonium diethylenetriaminepenta(methylenephosphonic acid); the anionic phosphorus / nitrogen / silicon flame retardant and polyacrylamide are deposited on the nylon / cotton blended fabric through ionic bonding, and are bonded to the nylon / cotton blended fabric through covalent bonds and supramolecular forces, thereby providing durable flame retardant properties;

[0030] (2) The present invention provides a method for preparing a durable flame retardant and smoke suppressant nylon / cotton blended fabric. The phosphoric acid in the anionic phosphorus / nitrogen / silicon flame retardant, the amide structure of polyacrylamide and the silicon-containing flame retardant group improve the flame retardant properties of the nylon / cotton blended fabric through a synergistic flame retardant effect. Therefore, the prepared durable flame retardant and smoke suppressant nylon / cotton blended fabric has excellent flame retardant and smoke suppressant properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of the cross-linking mechanism of anionic phosphorus / nitrogen / silicon flame retardants and nylon / cotton blended fabrics;

[0032] Figure 2 It is a comparison chart of smoke release curves of nylon / cotton blended fabric and the durable flame retardant and smoke suppressant nylon / cotton blended fabric of Example 1 (i.e. the coated nylon / cotton blended fabric in the figure). DETAILED DESCRIPTION

[0033] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended 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 fall within the scope limited by the appended claims of the application equally.

[0034] The test methods involved in the performance indicators in the embodiments and comparative examples of the present invention are as follows:

[0035] Limiting oxygen index: Tested in accordance with GB / T 5454-1997 "Oxygen Index Method for Textile Combustion Performance Test".

[0036] Damage length: measured in accordance with GB / T 5455-2014 "Determination of smoldering and afterflaming time of damage length in vertical direction of burning performance of textiles".

[0037] Total smoke release: The total smoke release of the sample was tested and characterized using a VOUCH 6810 cone calorimeter in accordance with ISO 5660-1 standard.

[0038] Damage length after 40 washes: First wash the fabric 40 times with water according to AATCC 61-2013 "Accelerated test for color fastness to household and commercial washing" standard, and then test the damage length of the fabric with reference to GB / T 5455-2014 "Determination of damage length in vertical direction, smoldering and afterflaming time of textile combustion performance" standard.

[0039] Example 1

[0040] A method for preparing a durable flame-retardant and smoke-suppressing nylon / cotton blended fabric comprises the following steps:

[0041] (1) Diethylenetriamine penta (methylenephosphonic acid) was added to water, and ammonia water was added to adjust the pH value to 5 to obtain solution A, and then an ethanol solution of tetraethyl orthosilicate was added dropwise to solution A at a rate of 0.5 mL / min, and dicyandiamide was added after reacting at a temperature of 60°C for 3 hours to obtain a solution containing anionic phosphorus / nitrogen / silicon flame retardant;

[0042] Taking the solution containing anionic phosphorus / nitrogen / silicon flame retardant as the benchmark, the dosage of diethylenetriaminepenta(methylenephosphonic acid) is 40 g / L, the dosage of tetraethyl orthosilicate is 10 g / L, and the dosage of dicyandiamide is 20 g / L; in the ethanol solution of tetraethyl orthosilicate, the mass ratio of tetraethyl orthosilicate to ethanol is 1:1;

[0043] (2) immersing a nylon / cotton blended fabric having a nylon content of 20 wt% into the solution containing anionic phosphorus / nitrogen / silicon flame retardants obtained in step (1), performing double immersion and double rolling, controlling the rolling residue rate to be 90%, and then performing baking treatment;

[0044] The baking process parameters are: pre-baking temperature 70°C, pre-baking time 3 min, baking temperature 160°C, baking time 4 min;

[0045] (3) immersing the nylon / cotton blended fabric treated in step (2) in a polyacrylamide solution with a concentration of 10 g / L, performing double immersion and double rolling, controlling the rolling rate to be 90%, and then drying the fabric at a temperature of 70°C for 3 min;

[0046] (4) Step (2) and step (3) are repeated twice to obtain a durable flame retardant and smoke suppressant nylon / cotton blended fabric.

[0047] The final durable flame retardant and smoke suppression nylon / cotton blended fabric had a limiting oxygen index of 30.5% and a damaged length of 9.2 cm. After 40 washes, the damaged length was 14.7 cm.

[0048] like Figure 2 As shown, the total smoke release of nylon / cotton blended fabric is 0.65m 2 The total smoke release of the durable flame retardant and smoke suppression nylon / cotton blended fabric is 0.37m 2 .

[0049] Comparative Example 1

[0050] A method for preparing a modified nylon / cotton blended fabric is basically the same as that of Example 1, except that the ethanol solution of tetraethyl orthosilicate is not added in step (1).

[0051] The final modified nylon / cotton blended fabric had a limiting oxygen index of 29.6%, a damaged length of 10.3 cm, and a total smoke release of 0.73 m 2 After 40 washes, the damaged length was 30cm.

[0052] By comparing Comparative Example 1 with Example 1, it can be found that when tetraethyl orthosilicate is not added, the flame retardant properties of the modified nylon / cotton blended fabric are reduced, the smoke release performance is increased, and the water washing resistance is reduced. This is because the network-like silica sol molecular structure modified by diethylenetriaminepenta(methylenephosphonic acid) is large, and it is deposited on the nylon / cotton blended fabric through ionic bonding with polyacrylamide, while although the single diethylenetriaminepenta(methylenephosphonic acid) can be bonded with polyacrylamide through ionic bonding, it still maintains good water solubility, and its water washing resistance is reduced; in addition, the silicon-containing network can produce silicon-containing oxides during the combustion process, which helps to inhibit the generation of smoke.

[0053] Example 2

[0054] A method for preparing a durable flame-retardant and smoke-suppressing nylon / cotton blended fabric comprises the following steps:

[0055] (1) Diethylenetriamine penta (methylenephosphonic acid) was added to water, and ammonia water was added to adjust the pH value to 5.3 to obtain solution A, and then tetraethyl orthosilicate ethanol solution was added dropwise to solution A at a rate of 0.6 mL / min, and dicyandiamide was added after reacting at a temperature of 55°C for 2.8 hours to obtain a solution containing anionic phosphorus / nitrogen / silicon flame retardant;

[0056] Based on the solution containing anionic phosphorus / nitrogen / silicon flame retardant, the dosage of diethylenetriaminepenta(methylenephosphonic acid) is 45 g / L, the dosage of tetraethyl orthosilicate is 13 g / L, and the dosage of dicyandiamide is 24 g / L; in the ethanol solution of tetraethyl orthosilicate, the mass ratio of tetraethyl orthosilicate to ethanol is 1.5:1;

[0057] (2) immersing a nylon / cotton blended fabric having a nylon content of 50 wt% into the solution containing anionic phosphorus / nitrogen / silicon flame retardants obtained in step (1), performing double immersion and double rolling, controlling the rolling rate to be 95%, and then performing baking treatment;

[0058] The baking process parameters are: pre-baking temperature 75°C, pre-baking time 3 min, baking temperature 165°C, baking time 3.5 min;

[0059] (3) immersing the nylon / cotton blended fabric treated in step (2) in a polyacrylamide solution with a concentration of 13 g / L, performing double immersion and double rolling, controlling the rolling rate to be 98%, and then drying the fabric at a temperature of 75° C. for 2.75 min;

[0060] (4) Step (2) and step (3) are repeated twice to obtain a durable flame retardant and smoke suppressant nylon / cotton blended fabric.

[0061] The resulting durable flame retardant and smoke-suppressing nylon / cotton blended fabric has a limiting oxygen index of 31.6%, a damaged length of 8.6 cm, and a total smoke release of 0.33 m 2 After 40 washes, the damaged length was 13.9 cm.

[0062] Example 3

[0063] A method for preparing a durable flame-retardant and smoke-suppressing nylon / cotton blended fabric comprises the following steps:

[0064] (1) Diethylenetriamine penta (methylenephosphonic acid) was added to water, and ammonia water was added to adjust the pH value to 5.5 to obtain solution A, and then tetraethyl orthosilicate ethanol solution was added dropwise to solution A at a rate of 0.8 mL / min, and dicyandiamide was added after reacting at a temperature of 52°C for 2.5 hours to obtain a solution containing anionic phosphorus / nitrogen / silicon flame retardant;

[0065] Based on the solution containing anionic phosphorus / nitrogen / silicon flame retardant, the dosage of diethylenetriaminepenta(methylenephosphonic acid) is 50 g / L, the dosage of tetraethyl orthosilicate is 15 g / L, and the dosage of dicyandiamide is 27 g / L; in the ethanol solution of tetraethyl orthosilicate, the mass ratio of tetraethyl orthosilicate to ethanol is 1.8:1;

[0066] (2) immersing a nylon / cotton blended fabric having a nylon content of 65 wt% into the solution containing anionic phosphorus / nitrogen / silicon flame retardants obtained in step (1), performing double immersion and double rolling, controlling the rolling ratio to be 100%, and then performing baking treatment;

[0067] The baking process parameters are: pre-baking temperature 80°C, pre-baking time 2.5 min, baking temperature 170°C, baking time 3 min;

[0068] (3) immersing the nylon / cotton blended fabric treated in step (2) in a polyacrylamide solution with a concentration of 18 g / L, performing double immersion and double rolling, controlling the rolling rate to be 105%, and then drying the fabric at a temperature of 80° C. for 2.5 min;

[0069] (4) Step (2) and step (3) are repeated three times to obtain a durable flame retardant and smoke suppressant nylon / cotton blended fabric.

[0070] The resulting durable flame retardant and smoke-suppressing nylon / cotton blended fabric has a limiting oxygen index of 32.4%, a damaged length of 8.2 cm, and a total smoke release of 0.3 m 2 After 40 washes, the damaged length was 13.5 cm.

[0071] Example 4

[0072] A method for preparing a durable flame-retardant and smoke-suppressing nylon / cotton blended fabric comprises the following steps:

[0073] (1) Diethylenetriamine penta (methylenephosphonic acid) was added to water, and ammonia water was added to adjust the pH value to 6 to obtain solution A, and then an ethanol solution of tetraethyl orthosilicate was added dropwise to solution A at a rate of 1 mL / min, and dicyandiamide was added after reacting at a temperature of 50°C for 2 hours to obtain a solution containing anionic phosphorus / nitrogen / silicon flame retardant;

[0074] Taking the solution containing anionic phosphorus / nitrogen / silicon flame retardant as the benchmark, the dosage of diethylenetriaminepenta(methylenephosphonic acid) is 60 g / L, the dosage of tetraethyl orthosilicate is 20 g / L, and the dosage of dicyandiamide is 30 g / L; in the ethanol solution of tetraethyl orthosilicate, the mass ratio of tetraethyl orthosilicate to ethanol is 2:1;

[0075] (2) immersing a nylon / cotton blended fabric having a nylon content of 80 wt% into the solution containing anionic phosphorus / nitrogen / silicon flame retardants obtained in step (1), performing double immersion and double rolling, controlling the rolling ratio to be 110%, and then performing baking treatment;

[0076] The baking process parameters are: pre-baking temperature 90°C, pre-baking time 2 min, baking temperature 162°C, baking time 3.75 min;

[0077] (3) immersing the nylon / cotton blended fabric treated in step (2) in a polyacrylamide solution with a concentration of 20 g / L, performing double immersion and double rolling, controlling the rolling rate to be 110%, and then drying the fabric at a temperature of 90° C. for 2 min;

[0078] (4) Step (2) and step (3) are repeated three times to obtain a durable flame retardant and smoke suppressant nylon / cotton blended fabric.

[0079] The resulting durable flame retardant and smoke-suppressing nylon / cotton blended fabric has a limiting oxygen index of 33.1%, a damaged length of 7.9 cm, and a total smoke release of 0.28 m 2 After 40 washes, the damaged length was 13 cm.

Claims

1. A method for preparing a durable flame retardant and smoke-suppressing nylon / cotton blended fabric, characterized in that The steps include: (1) Diethylenetriamine penta (methylenephosphonic acid) was added to water, and ammonia water was added to adjust the pH value to 5-6 to obtain solution A, and then tetraethyl orthosilicate ethanol solution was added dropwise to solution A at a rate of 0.5-1 mL / min. After the reaction, dicyandiamide was added to obtain a solution containing anionic phosphorus / nitrogen / silicon flame retardant; (2) immersing the nylon / cotton blended fabric into the solution containing the anionic phosphorus / nitrogen / silicon flame retardant obtained in step (1), and performing padding and baking treatments; (3) immersing the nylon / cotton blended fabric treated in step (2) into a polyacrylamide solution, and performing padding and drying treatments; (4) Step (2) and step (3) are repeated 2 to 3 times to obtain a durable flame retardant and smoke suppressing nylon / cotton blended fabric.

2. The method for preparing a durable flame retardant and smoke suppressant nylon / cotton blended fabric according to claim 1, characterized in that: In step (1), based on the solution containing anionic phosphorus / nitrogen / silicon flame retardant, the amount of diethylenetriaminepenta(methylenephosphonic acid) is 40-60 g / L, the amount of tetraethyl orthosilicate is 10-20 g / L, and the amount of dicyandiamide is 20-30 g / L.

3. The method for preparing a durable flame retardant and smoke suppressant nylon / cotton blended fabric according to claim 1, characterized in that: In the ethanol solution of tetraethyl orthosilicate in step (1), the mass ratio of tetraethyl orthosilicate to ethanol is 1-2:

1.

4. The method for preparing a durable flame retardant and smoke suppressant nylon / cotton blended fabric according to claim 1, characterized in that: In step (1), the reaction temperature is 50-60° C., and the reaction time after the ethanol solution of tetraethyl orthosilicate is added dropwise is 2-3 hours.

5. The method for preparing a durable flame retardant and smoke suppressant nylon / cotton blended fabric according to claim 1, characterized in that: In step (2), the dipping and rolling are performed twice, and the rolling rate is 90-110%.

6. The method for preparing a durable flame retardant and smoke suppressant nylon / cotton blended fabric according to claim 5, characterized in that: The baking process parameters in step (2) are: pre-baking temperature of 70-90°C, pre-baking time of 2-3 min, baking temperature of 160-170°C, and baking time of 3-4 min.

7. The method for preparing a durable flame retardant and smoke suppressant nylon / cotton blended fabric according to claim 1, characterized in that: The concentration of the polyacrylamide solution in step (3) is 10-20 g / L.

8. The method for preparing a durable flame retardant and smoke suppressant nylon / cotton blended fabric according to claim 7, characterized in that: In step (3), the dipping and rolling are performed twice, and the rolling rate is 90-110%.

9. The method for preparing a durable flame retardant and smoke suppressant nylon / cotton blended fabric according to claim 8, characterized in that: In step (3), the drying temperature is 70-90°C and the drying time is 2-3 minutes.

10. The method for preparing a durable flame retardant and smoke suppressant nylon / cotton blended fabric according to any one of claims 1 to 9, characterized in that: The limiting oxygen index of durable flame retardant and smoke suppression nylon / cotton blended fabric is not less than 30.5%, the damaged length is not higher than 9.2cm, and the total smoke release is not higher than 0.37m 2 After 40 washes, the damaged length is still no more than 14.7cm.

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