Preparation method of polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene

Abstract

The present invention belongs to the technical field of flame retardant modification of fabrics, and discloses a preparation method of polyamide 6 fabric flame retarded by amino-modified cyclotriphosphazene. The preparation method is as follows: Dissolve the amino-modified cyclotriphosphazene flame retardant and cyanuric chloride in an organic solvent to obtain a flame retardant solution, and immerse the polyamide 6 fabric in the flame retardant solution for impregnation treatment to obtain the polyamide 6 fabric flame retarded by amino-modified cyclotriphosphazene. The present invention can graft and fix the flame retardant film on the surface of the polyamide 6 fabric only through a small amount of covalent bond combination, so as to provide an efficient and durable flame retardant function.

Description

Technical Field

[0001] The present invention belongs to the technical field of fabric flame retardant modification, and relates to a preparation method of polyamide 6 fabric based on amino-modified cyclotriphosphazene flame retardant. Background Art

[0002] Due to its excellent mechanical strength, outstanding abrasion resistance, low density, and good hygroscopicity, polyamide 6 fiber has been widely used in many fields such as clothing, home textiles, and industrial textiles. However, the limiting oxygen index of this fiber is only 21%, belonging to the category of combustible fibers. In particular, since polyamide 6 fiber products are often designed to be thin and have a large specific surface area, once they catch fire, their burning speed is relatively fast, and serious melting and dripping phenomena occur. Such characteristics are extremely likely to trigger or exacerbate fires, thus posing a serious threat to people's lives and property safety. Therefore, it is particularly important and urgent to improve the flame retardancy and anti-melting and dripping properties of polyamide 6 fabrics.

[0003] In the process of exploring flame retardant materials, hexachlorocyclotriphosphazene (HCCP) has attracted much attention due to its unique phosphorus-nitrogen alternating ring structure. The phosphorus and nitrogen elements in this structure exhibit good flame retardant synergistic effects, providing the possibility for improving the flame retardant properties of materials. However, hexachlorocyclotriphosphazene has high activity and shows instability during application, which limits its feasibility for directly flame retardant modification of polyamide 6 fabrics. Nevertheless, its research value in the field of flame retardancy cannot be ignored, and it also provides valuable ideas and directions for the development of new flame retardant materials.

[0004] As described in the literature (Study on the flame retardancy of wool fabric with hexakis(4-aminophenoxy)cyclotriphosphazene [J]. Textile Auxiliaries, 2016(12):49-53.), hexakis(4-aminophenoxy)cyclotriphosphazene, a derivative of hexachlorocyclotriphosphazene, was used for the flame retardant finishing of wool fabric by the pad-roll-dry method. Due to the relatively high content of amino groups on wool fibers, this characteristic enables hexakis(4-aminophenoxy)cyclotriphosphazene to combine with wool through ionic bonds. However, the content of active amino groups on polyamide 6 fabrics is relatively low, making it difficult to graft a sufficient amount of flame retardant onto polyamide 6 fabrics, and thus unable to effectively improve the flame retardant properties and flame retardant washability of polyamide 6 fabrics.

[0005] Therefore, it is of great significance to study a preparation method of polyamide 6 fabric based on amino-modified cyclotriphosphazene flame retardant to solve the above problems. Summary of the Invention

[0006] The purpose of the present invention is to solve the problems existing in the prior art and provide a preparation method of polyamide 6 fabric based on amino-modified cyclotriphosphazene flame retardant.

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

[0008] A preparation method of polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene. Dissolve the amino-modified cyclotriphosphazene flame retardant and cyanuric chloride in an organic solvent to obtain a flame-retardant solution. Immerse the polyamide 6 fabric in the flame-retardant solution for impregnation treatment, and dry or bake it at room temperature to obtain the polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene.

[0009] The chemical formula of the amino-modified cyclotriphosphazene flame retardant is .

[0010] As a preferred technical solution:

[0011] For the preparation method of polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene as described above, the damaged length of the unmodified polyamide 6 fabric is 30 cm, the limiting oxygen index is 20.1%, there is dripping and it can ignite absorbent cotton. The limiting oxygen index of the polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene is not less than 29.8%, the damaged length is not more than 10.5 cm, there is no dripping. After 50 washes, it can still pass the vertical burning test, and the damaged length is not more than 14.6 cm, there is no dripping. This shows that the polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene prepared by the present invention has good flame retardancy and washability.

[0012] For the preparation method of polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene as described above, the preparation method of the amino-modified cyclotriphosphazene flame retardant is: dissolve hexachlorocyclotriphosphazene and ethylenediamine in chloroform, use triethylamine as an acid-binding agent, react at 20 - 30 °C for 4 - 5 h, and then obtain the amino-modified cyclotriphosphazene flame retardant by vacuum distillation.

[0013] For the preparation method of polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene as described above, the molar ratio of hexachlorocyclotriphosphazene to ethylenediamine is 1:6 - 6.6. Theoretically, every mole of hexachlorocyclotriphosphazene undergoes a nucleophilic substitution reaction with six moles of ethylenediamine, and the molar ratio of hexachlorocyclotriphosphazene to triethylamine is 1:6 - 7.

[0014] For the preparation method of polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene as described above, the temperature of vacuum distillation is 40 - 50 °C, and the vacuum degree is 1.5 - 2.0 kPa.

[0015] For the preparation method of polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene as described above, the organic solvent is a mixed solution of acetone and distilled water, and acetone accounts for 15 - 20% of the total volume of the organic solvent.

[0016] A preparation method of a polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene as described above, wherein the content of the amino-modified cyclotriphosphazene flame retardant in the flame-retardant liquid is 70-100 g / L, and the content of cyanuric chloride is 40-60 g / L. The higher the dosage of the flame retardant, the more helpful it is to improve the flame-retardant performance of the polyamide 6 fabric, but too high dosage will cause waste.

[0017] A preparation method of a polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene as described above, wherein the bath ratio for impregnation is 1:30-40; after impregnation, it is oscillated at 75-85 °C for 50-70 min.

[0018] The principle of the present invention is:

[0019] Hexachlorocyclotriphosphazene has a high phosphorus content and a high nitrogen content. However, hexachlorocyclotriphosphazene has high activity and is unstable during application, making it difficult to be directly applied to the flame-retardant modification of polyamide 6 fabric; moreover, the content of active groups on the surface of polyamide 6 fabric is small, and it is difficult to graft a sufficient amount of flame retardant molecules onto the surface of polyamide 6 fabric through covalent bond grafting reaction, and the flame-retardant durability needs to be further improved.

[0020] The active chlorine of hexachlorocyclotriphosphazene can undergo a nucleophilic substitution reaction with the amino group of ethylenediamine, thereby preparing an amino-modified cyclotriphosphazene flame retardant. On the one hand, the surface of the amino-modified cyclotriphosphazene flame retardant is rich in amino groups, which can undergo a nucleophilic substitution reaction with the active chlorine of cyanuric chloride, thereby in-situ generating a flame-retardant polymer on the surface of the polyamide 6 fabric; on the other hand, the excess active chlorine of cyanuric chloride can undergo a nucleophilic substitution reaction with the amino group on the polyamide 6 fabric. The reaction conditions are mild and the reaction efficiency is high. Therefore, the flame-retardant polymer is grafted onto the surface of the polyamide 6 fabric through covalent bonds. Even though the content of active amino groups on the polyamide 6 fabric is small, the reaction activity between cyanuric chloride and the amino-modified cyclotriphosphazene flame retardant is high, and the generated polymer is extremely easy to form a film (flame-retardant film) on the fabric surface. Therefore, the flame-retardant film can be grafted and fixed on the fabric surface only through a small amount of covalent bond binding, thereby providing an efficient and durable flame-retardant function.

[0021] In addition, the phosphate group of the amino-modified cyclotriphosphazene flame retardant can act as an acid source, and the amino groups of the amino-modified cyclotriphosphazene flame retardant and ethylenediamine can act as a gas source. Cyanuric chloride not only acts as a cross-linking agent but also acts as a triazine-based charring agent, with high charring efficiency, and can organically construct an intumescent flame-retardant system, having good flame-retardant effect, and can effectively improve the flame-retardant performance of the polyamide 6 fabric; and because it promotes the charring of the polyamide 6 fabric, the melt dripping phenomenon is reduced.

[0022] Beneficial effects:

[0023] (1)The amino-modified cyclotriphosphazene flame retardant prepared by the present invention is rich in amino groups on its surface, which can undergo nucleophilic substitution reactions with the active chlorine of cyanuric chloride, thereby in-situ generating a flame-retardant polymer on the surface of nylon 6 fabric; moreover, the excess active chlorine of cyanuric chloride can react with the amino groups on the nylon 6 fabric through nucleophilic substitution reactions, and finally, the flame-retardant film can be grafted and fixed on the fabric surface only through a small number of covalent bonds, thereby providing an efficient and durable flame-retardant function.

[0024] (2)The phosphate groups of the amino-modified cyclotriphosphazene flame retardant prepared by the present invention can act as acid sources, and the amino groups of the amino-modified cyclotriphosphazene flame retardant and ethylenediamine can act as gas sources. The cyanuric chloride used not only acts as a cross-linking agent but also as a triazine-based charring agent, which can organically construct an intumescent flame-retardant system with good flame-retardant effects and can effectively improve the flame-retardant performance of nylon 6 fabric. Brief Description of the Drawings

[0025] Figure 1 It is the nuclear magnetic resonance carbon spectrum of the amino-modified cyclotriphosphazene flame retardant prepared by the present invention. Detailed Embodiments

[0026] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these examples 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.

[0027] The test methods for the relevant performance indicators in the following examples and comparative examples are as follows:

[0028] Limiting oxygen index: The limiting oxygen index of the nylon 6 fabric flame-retarded with amino-modified cyclotriphosphazene prepared in the following examples and the cyclotriphosphazene flame-retarded nylon 6 fabric prepared in the comparative examples was determined by using GB / T 5454-1997 "Textiles - Burning performance - Oxygen index method".

[0029] Damage length and melt dripping performance: The damage length and melt dripping performance of the nylon 6 fabric flame-retarded with amino-modified cyclotriphosphazene prepared in the following examples and the cyclotriphosphazene flame-retarded nylon 6 fabric prepared in the comparative examples were determined by using GB / T 5455-2014 "Textiles - Burning performance - Determination of damage length, smoldering and afterflaming time in vertical direction".

[0030] Length of damage and melting drop performance after 50 washes: First, refer to the standard of AATCC 61-2013 "Accelerated Test for Colorfastness to Laundering, Home and Commercial" to wash the polyamide 6 fabrics flame-retarded by amino-modified cyclotriphosphazene prepared in the following examples and the polyamide 6 fabrics flame-retarded by cyclotriphosphazene prepared in each comparative example 50 times, and then refer to the standard of GB / T 5455-2014 "Textiles - Burning Behavior - Determination of the Length of Damage, Smoldering and Afterflaming Time in the Vertical Direction" to test the length of damage and melting drop performance of the polyamide 6 fabrics flame-retarded by amino-modified cyclotriphosphazene and the polyamide 6 fabrics flame-retarded by cyclotriphosphazene after washing.

[0031] Residual carbon content: The residual carbon content of the fabric is the mass retention rate at 800 °C under nitrogen conditions in the thermal analysis test, and the heating rate is 10 °C / min.

[0032] Example 1

[0033] A preparation method of a polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene, the steps are as follows:

[0034] (1) Prepare amino-modified cyclotriphosphazene flame retardant;

[0035] Dissolve hexachlorocyclotriphosphazene and ethylenediamine in chloroform, use triethylamine as an acid-binding agent, react at 20 °C for 5 h, and then obtain amino-modified cyclotriphosphazene flame retardant through vacuum distillation and ethanol washing; among them, the molar ratio of hexachlorocyclotriphosphazene to ethylenediamine is 1:6, the molar ratio of hexachlorocyclotriphosphazene to triethylamine is 1:6, and the mass ratio of chloroform to hexachlorocyclotriphosphazene is 30:1; the temperature of vacuum distillation is 40 °C, and the vacuum degree is 2 kPa;

[0036] The chemical formula of the prepared amino-modified cyclotriphosphazene flame retardant is , and its nuclear magnetic resonance carbon spectrum is as shown in Figure 1 . It can be seen from the figure that the chemical shifts at 42.0 ppm and 40.1 ppm are caused by the carbon elements connected to the unreacted amino group and the reacted amino group, which also indicates that the amino-modified cyclotriphosphazene flame retardant is successfully synthesized in this example;

[0037] (2) Dissolve the amino-modified cyclotriphosphazene flame retardant prepared in step (1) and cyanuric chloride in a mixed solution of acetone and distilled water to obtain a flame retardant solution, and then immerse the polyamide 6 fabric (manufacturer: Wujiang Fuhua Weaving Co., Ltd., gram weight: 112.8 g / m 2 ) into the flame retardant solution according to a bath ratio of 1:30, then oscillate at 75 °C for 70 min, and finally dry at room temperature to obtain a polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene; among them, acetone accounts for 15% of the total volume of the mixed solution of acetone and distilled water, the content of amino-modified cyclotriphosphazene flame retardant in the flame retardant solution is 70 g / L, and the content of cyanuric chloride is 40 g / L.

[0038] The final nylon 6 fabric based on amino-modified cyclotriphosphazene flame retardant had a limiting oxygen index of 29.8%, a damaged length of 10.5 cm, no molten droplets were produced, and it could still pass the vertical burning test after 50 washes, with a damaged length of 14.6 cm, and no molten droplets were produced; using an 800°C muffle furnace calcination test, the residual carbon content of the nylon 6 fabric based on amino-modified cyclotriphosphazene flame retardant was 5.9%.

[0039] Comparative Example 1

[0040] A method for preparing a cyclotriphosphazene flame-retardant nylon 6 fabric is basically the same as that in Example 1, except that step (1) is not performed, and the amino-modified cyclotriphosphazene flame retardant in step (2) is replaced by a novel polyphosphazene flame retardant prepared in a document of equal quality (Preparation and flame retardant properties of modified hexachlorocyclotriphosphazene [J]. Shandong Chemical Industry, 2021, 50(1): 17-19). The preparation process of the novel polyphosphazene flame retardant is as follows: 1 g of hexachlorocyclotriphosphazene and 20 mL of toluene are added to a 250 mL three-necked flask and fully dissolved, 3.4 g of rhodamine B-amide prepared in the document is added thereto and stirred evenly, then N2 is introduced for protection and the temperature is raised to 70°C, 20 mL of triethylamine is added, and after reacting for 6 h, water is poured into the mixture to precipitate a large amount of solid, and the novel polyphosphazene flame retardant is obtained after filtration.

[0041] The cyclotriphosphazene flame-retardant nylon 6 fabric finally obtained had a limiting oxygen index of 28.2%, a damaged length of 12.1 cm, no droplets were generated, and after 5 washes, the flame retardant effect was lost and droplets were generated.

[0042] By comparing Comparative Example 1 with Example 1, it can be seen that the flame retardant performance and water washing resistance of the flame retardant nylon 6 fabric prepared in Comparative Example 1 are significantly reduced. This is because the new polyphosphazene flame retardant in Comparative Example 1 is not reactive and cannot react with cyanuric chloride. It can only be deposited on the surface of nylon 6 fabric by physical action, resulting in poor flame retardant performance of the cyclotriphosphazene flame retardant nylon 6 fabric prepared, and the flame retardant durability is greatly reduced.

[0043] Example 2

[0044] A method for preparing a flame-retardant nylon 6 fabric based on amino-modified cyclotriphosphazene, comprising the following steps:

[0045] (1) Preparation of amino-modified cyclotriphosphazene flame retardant;

[0046] Hexachlorocyclotriphosphazene and ethylenediamine were dissolved in chloroform. Triethylamine was used as an acid-binding agent and the reaction was carried out at 25 °C for 4.7 h. Then, the amino-modified cyclotriphosphazene flame retardant was obtained through vacuum distillation and ethanol washing. Among them, the molar ratio of hexachlorocyclotriphosphazene to ethylenediamine was 1:6.2, the molar ratio of hexachlorocyclotriphosphazene to triethylamine was 1:6.3, and the mass ratio of chloroform to hexachlorocyclotriphosphazene was 33:1. The temperature of vacuum distillation was 43 °C and the vacuum degree was 1.8 kPa.

[0047] The chemical formula of the prepared amino-modified cyclotriphosphazene flame retardant is ;

[0048] (2) The amino-modified cyclotriphosphazene flame retardant prepared in step (1) and cyanuric chloride were dissolved in a mixed solution of acetone and distilled water to obtain a flame retardant solution. Then, the polyamide 6 fabric (manufactured by Wujiang Fuhua Weaving Co., Ltd., with a gram weight of 112.8 g / m 2 ) was immersed in the flame retardant solution at a bath ratio of 1:40, then oscillated at 80 °C for 60 min, and finally air-dried at room temperature to obtain the polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene. Among them, acetone accounted for 18% of the total volume of the mixed solution of acetone and distilled water, the content of the amino-modified cyclotriphosphazene flame retardant in the flame retardant solution was 80 g / L, and the content of cyanuric chloride was 45 g / L.

[0049] The limiting oxygen index of the finally prepared polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene was 30.9%, the damage length was 9.6 cm, no melt dripping occurred, and it could still pass the vertical burning test after 50 washes, and the damage length was 14 cm and no melt dripping occurred. When tested by calcination in a muffle furnace at 800 °C, the residual carbon content of the polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene was 7.3%.

[0050] Example 3

[0051] A preparation method of a polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene is as follows:

[0052] (1) Prepare an amino-modified cyclotriphosphazene flame retardant;

[0053] Hexachlorocyclotriphosphazene and ethylenediamine were dissolved in chloroform. Triethylamine was used as an acid-binding agent and the reaction was carried out at 28 °C for 4.4 h. Then, the amino-modified cyclotriphosphazene flame retardant was obtained through vacuum distillation. Among them, the molar ratio of hexachlorocyclotriphosphazene to ethylenediamine was 1:6.4, the molar ratio of hexachlorocyclotriphosphazene to triethylamine was 1:6.6, and the mass ratio of chloroform to hexachlorocyclotriphosphazene was 35:1. The temperature of vacuum distillation was 48 °C and the vacuum degree was 1.6 kPa.

[0054] The chemical formula of the prepared amino-modified cyclotriphosphazene flame retardant is ;

[0055] (2) Dissolve the amino-modified cyclotriphosphazene flame retardant prepared in step (1) and cyanuric chloride in a mixed solution of acetone and distilled water to obtain a flame retardant solution. Then, immerse the polyamide 6 fabric (manufactured by Wujiang Fuhua Weaving Co., Ltd., with a gram weight of 112.8 g / m 2 ) into the flame retardant solution at a liquor ratio of 1:35, then oscillate at 85 °C for 50 min, and finally dry it at room temperature to obtain the polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene; among them, acetone accounts for 20% of the total volume of the mixed solution of acetone and distilled water, the content of the amino-modified cyclotriphosphazene flame retardant in the flame retardant solution is 90 g / L, and the content of cyanuric chloride is 50 g / L.

[0056] The limiting oxygen index of the finally obtained polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene is 31.6%, the damage length is 9.1 cm, no melt dripping occurs, and it can still pass the vertical burning test after 50 washes, and the damage length is 13.4 cm, no melt dripping occurs; using an 800 °C muffle furnace calcination test, the residual carbon content of the polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene is 8.6%.

[0057] Example 4

[0058] A preparation method of a polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene, the steps are as follows:

[0059] (1) Prepare an amino-modified cyclotriphosphazene flame retardant;

[0060] Dissolve hexachlorocyclotriphosphazene and ethylenediamine in chloroform, use triethylamine as an acid-binding agent, react at 30 °C for 4 h, and then obtain the amino-modified cyclotriphosphazene flame retardant through reduced pressure distillation and ethanol washing; among them, the molar ratio of hexachlorocyclotriphosphazene to ethylenediamine is 1:6.6, the molar ratio of hexachlorocyclotriphosphazene to triethylamine is 1:7, and the mass ratio of chloroform to hexachlorocyclotriphosphazene is 40:1; the temperature of reduced pressure distillation is 50 °C, and the vacuum degree is 1.5 kPa;

[0061] The chemical formula of the prepared amino-modified cyclotriphosphazene flame retardant is ;

[0062] (2) Dissolve the amino-modified cyclotriphosphazene flame retardant prepared in step (1) and cyanuric chloride in a mixed solution of acetone and distilled water to obtain a flame retardant solution. Then, immerse the polyamide 6 fabric (manufactured by Wujiang Fuhua Weaving Co., Ltd., with a gram weight of 112.8 g / m 2 ) into the flame retardant solution at a liquor ratio of 1:40, then oscillate at 85 °C for 55 min, and finally dry it at room temperature to obtain the polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene; among them, acetone accounts for 20% of the total volume of the mixed solution of acetone and distilled water, the content of the amino-modified cyclotriphosphazene flame retardant in the flame retardant solution is 100 g / L, and the content of cyanuric chloride is 60 g / L.

[0063] The limiting oxygen index of the finally prepared polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene is 32.3%, the damaged length is 8.7 cm, no melt dripping occurs, it can still pass the vertical burning test after 50 washes, and the damaged length is 13.1 cm, no melt dripping occurs; when tested by calcination in a muffle furnace at 800 °C, the carbon residue of the polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene is 10.2%.

Claims

1. A preparation method of a polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene, characterized in that: Dissolve the amino-modified cyclotriphosphazene flame retardant and cyanuric chloride in an organic solvent to obtain a flame retardant solution. Immerse the polyamide 6 fabric in the flame retardant solution for impregnation treatment. After impregnation, oscillate at 75 - 85 °C for 50 - 70 min to obtain the polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene. The chemical formula of the amino-modified cyclotriphosphazene flame retardant is ; The preparation method of the amino-modified cyclotriphosphazene flame retardant is as follows: Dissolve hexachlorocyclotriphosphazene and ethylenediamine in chloroform, use triethylamine as an acid-binding agent, react at 20 - 30 °C for 4 - 5 h, and then obtain the amino-modified cyclotriphosphazene flame retardant through vacuum distillation and ethanol washing. The limiting oxygen index of the polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene is not less than 29.8%, the char length is not higher than 10.5 cm, no melt dripping occurs, and it can still pass the vertical burning test after 50 washes, and the char length is not higher than 14.6 cm, no melt dripping occurs.

2. The preparation method of a polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene according to claim 1, characterized in that The molar ratio of hexachlorocyclotriphosphazene to ethylenediamine is 1:6 - 6.6, and the molar ratio of hexachlorocyclotriphosphazene to triethylamine is 1:6 - 7.

3. The preparation method of a polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene according to claim 1, characterized in that, The temperature of vacuum distillation is 40 - 50 °C, and the vacuum degree is 1.5 - 2.0 kPa.

4. The preparation method of a polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene according to claim 1, characterized in that, The organic solvent is a mixed solution of acetone and distilled water, and acetone accounts for 15 - 20% of the total volume of the organic solvent.

5. The preparation method of a polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene according to claim 1, characterized in that, The content of the amino-modified cyclotriphosphazene flame retardant in the flame retardant solution is 70 - 100 g / L, and the content of cyanuric chloride is 40 - 60 g / L.

6. The preparation method of a polyamide 6 fabric flame-retarded by amino-modified cyclotriphosphazene according to claim 1, characterized in that, The bath ratio of impregnation is 1:30 - 40.

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