A reactive flame retardant, a preparation method and application thereof, and an ultraviolet-resistant flame-retardant nylon 6 fabric and a preparation method thereof

Abstract

This invention belongs to the field of textile materials technology, and discloses a reactive flame retardant, its preparation method, and its application, as well as a UV-resistant flame-retardant nylon 6 fabric and its preparation method. This invention uses organosiloxanes as the molecular backbone to link nitrogen-based and phosphorus-based flame retardants, thus preparing a highly efficient multi-element flame retardant. Compared to commonly available nitrogen-based compound phosphorus-based flame retardants, the flame retardant of this invention generates char precursors and catalyzes carbon atom rearrangement during thermal decomposition. Simultaneously, its decomposition products, such as SiO2, enhance the stability of the char layer, exhibiting a more efficient char-promoting effect. Furthermore, the addition of rosmarinic acid endows the nylon 6 fabric with both flame retardancy and excellent UV resistance, achieving multi-functional modification of the nylon 6 fabric.

Description

Technical Field

[0001] This invention relates to the field of textile materials technology, and in particular to a reactive flame retardant, its preparation method and application, as well as an ultraviolet-resistant flame-retardant nylon 6 fabric and its preparation method. Background Technology

[0002] Nylon 6 fabrics are widely used in automotive interiors, outdoor sports, and military textiles due to their excellent mechanical properties and abrasion resistance. However, pure nylon 6 fabrics have a limiting oxygen index of only 20%, making them flammable. Furthermore, the burning of nylon 6 fabrics can cause dripping, leading to the spread of fire. In addition to flammability, nylon 6 fabrics have poor UV resistance. The amide bonds (-CO-NH-) and methylene groups (-CH2-) in its molecular structure are sensitive absorption sites for ultraviolet light, and exposure to sunlight can easily lead to photo-oxidation reactions that break these chemical bonds. These defects significantly hinder the application and development of nylon 6 fabrics.

[0003] Conventional flame retardants for nylon 6 fabrics have low flame retardant efficiency, requiring large amounts to achieve good flame retardant effects. However, large amounts of flame retardants also significantly affect the physical properties of nylon 6 fabrics. Therefore, a highly efficient flame retardant for nylon 6 fabrics urgently needs to be developed.

[0004] In flame retardants for nylon 6 fabrics, phosphorus-based flame retardants decompose upon heating, generating a large number of PO· free radicals that capture the free radicals produced during the decomposition of nylon 6 fabric, interrupting the free radical chain reaction and thus achieving a flame-retardant effect. Nitrogen-based flame retardants, on the other hand, form a dense carbon layer on the surface of nylon 6 fabric, interrupting the transfer of heat and combustible gases to achieve a flame-retardant effect. However, flame retardants based on a single flame-retardant principle have limited effectiveness, while silicone-based flame retardants, such as organosiloxanes, can serve as a molecular framework to link multiple flame retardants, thereby achieving the preparation of multi-component flame retardants. Therefore, the preparation of multi-component flame retardants based on silicone-based flame retardants is currently the mainstream research direction for flame retardants for nylon 6 fabrics. Summary of the Invention

[0005] The purpose of this invention is to provide a reactive flame retardant, its preparation method and application, as well as an ultraviolet-resistant flame-retardant nylon 6 fabric and its preparation method, thereby solving the above-mentioned problems existing in the prior art.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a reactive flame retardant, the structural formula of which is as follows: ; Where R1 is R2 is R3 is .

[0007] This invention also provides a method for preparing a reactive flame retardant, comprising the following steps: S1. Under a nitrogen atmosphere, glyoxal, γ-aminopropyltriethoxysilane and anhydrous ethanol are mixed and reacted to obtain Schiff base triethoxysiloxane. S2. In a nitrogen atmosphere, terephthalaldehyde, DOPO, and N,N-dimethylformamide are mixed and reacted to obtain a phosphorus-based flame retardant with a bisDOPO structure; S3. In a nitrogen atmosphere, Schiff base triethoxysiloxane, a phosphorus-based flame retardant with a DOPO structure, and anhydrous ethanol are mixed and reacted to obtain phosphorus-containing triethoxysiloxane. S4. In a nitrogen atmosphere, diphenylsilanediol, phosphorus-containing triethoxysiloxane, Schiff base triethoxysiloxane, and anhydrous ethanol are mixed, and the pH value is adjusted to 3.5-4.5 with acetic acid. Then the reaction is carried out to obtain the reactive flame retardant.

[0008] Preferably, in step S1, the molar ratio of glyoxal to γ-aminopropyltriethoxysilane is 1:2~4; the reaction temperature is 65~80℃; and the reaction time is 3~5h.

[0009] Preferably, in step S2, the molar ratio of terephthalaldehyde to DOPO is 1:2~5; the reaction temperature is 100~120℃; and the reaction time is 5~8h.

[0010] Preferably, in step S3, the molar ratio of the Schiff base triethoxysiloxane to the phosphorus-based flame retardant with a DOPO structure is 1:2~3; the reaction temperature is 70~90℃; and the reaction time is 2~5h.

[0011] Preferably, in step S4, the molar ratio of diphenylsilanediol, phosphorus-containing triethoxysiloxane, and Schiff base triethoxysiloxane is 1:1~3:1~3; the reaction temperature is 70~90℃; and the reaction time is 2~5h.

[0012] The present invention also provides the application of a reactive flame retardant or a reactive flame retardant prepared by the above preparation method in flame retardant finishing of nylon 6 fabrics.

[0013] This invention also provides a method for preparing UV-resistant flame-retardant nylon 6 fabric, comprising the following steps: Rosmarinic acid and reactive flame retardant are mixed to obtain a flame retardant solution; nylon 6 fabric is impregnated in the flame retardant solution, and then dried and cured in sequence to obtain UV-resistant flame-retardant nylon 6 fabric. The reactive flame retardant is one of the reactive flame retardants mentioned above or a reactive flame retardant prepared by the above preparation method.

[0014] Preferably, the impregnation temperature is 75~90℃; the impregnation time is 2~4h; the curing temperature is 130~160℃; and the curing time is 2~10min.

[0015] The present invention also provides an UV-resistant and flame-retardant nylon 6 fabric prepared by the above preparation method.

[0016] As can be seen from the above technical solution, compared with the prior art, the present invention has the following beneficial effects: (1) This invention uses organosiloxanes as the molecular backbone to link nitrogen-based and phosphorus-based flame retardants, thus preparing a highly efficient multi-element flame retardant. Compared with commonly available nitrogen-based compound phosphorus-based flame retardants, the flame retardant of this invention generates char precursors and catalyzes carbon atom rearrangement during thermal decomposition. At the same time, its decomposition products, such as SiO2, can enhance the stability of the char layer, exhibiting a more efficient char-promoting effect. Furthermore, the compounding with rosmarinic acid gives nylon 6 fabrics both flame retardancy and excellent UV resistance, achieving multifunctional modification of nylon 6 fabrics.

[0017] (2) The UV-resistant flame-retardant nylon 6 fabric prepared by this invention has excellent flame retardancy, achieving synergistic flame retardancy between the condensed phase and the gas phase. During combustion, the phosphorus-based flame retardant releases a large number of PO· free radicals, interrupting the free radical chain reaction during the combustion of the nylon 6 fabric. The silicon-based and nitrogen-based flame retardants generate char precursors during thermal decomposition and catalyze carbon atom rearrangement, forming a denser and more stable char layer to isolate the heat source and combustible gas, thus achieving highly efficient flame retardancy of the nylon 6 fabric.

[0018] (3) The UV-resistant and flame-retardant nylon 6 fabric prepared by the present invention has good UV resistance, and rosmarinic acid has excellent UV absorption performance. The UPF value of the nylon 6 fabric after being impregnated with rosmarinic acid is significantly improved. Detailed Implementation

[0019] This invention provides a reactive flame retardant, the structural formula of which is as follows: ; Where R1 is R2 is R3 is .

[0020] This invention also provides a method for preparing a reactive flame retardant, comprising the following steps: S1. The reaction process is as follows:

[0021] In a nitrogen atmosphere, glyoxal (GLY), γ-aminopropyltriethoxysilane (APTES), and anhydrous ethanol are mixed and reacted to obtain Schiff base triethoxysiloxane (GLY-TES). S2. The reaction process is as follows:

[0022] In a nitrogen atmosphere, terephthalaldehyde (TDCA), DOPO, and N,N-dimethylformamide (DMF) are mixed and reacted to obtain a phosphorus-based flame retardant with a double DOPO structure (TDCA-DOPO). S3. The reaction process is as follows:

[0023] In a nitrogen atmosphere, Schiff base triethoxysiloxane (GLY-TES), a phosphorus flame retardant with a double DOPO structure (TDCA-DOPO), and anhydrous ethanol are mixed and reacted to obtain phosphorus-containing triethoxysiloxane (GP-TES). S4. The reaction process is as follows:

[0024] In a nitrogen atmosphere, diphenylsilanediol (DPSD), phosphorus-containing triethoxysiloxane (GP-TES), Schiff base triethoxysiloxane (GLY-TES), and anhydrous ethanol are mixed, and the pH value is adjusted to 3.5-4.5 with acetic acid. Then, the reaction is carried out to obtain the reactive flame retardant (GPDSi flame retardant).

[0025] In this invention, in step S1, the molar ratio of glyoxal to γ-aminopropyltriethoxysilane is preferably 1:2 to 4, more preferably 1:4; the reaction temperature is preferably 65 to 80°C, more preferably 70°C; and the reaction time is preferably 3 to 5 hours, more preferably 4 hours.

[0026] In this invention, in step S2, the molar ratio of terephthalaldehyde to DOPO is preferably 1:2 to 5, more preferably 1:2; the reaction temperature is preferably 100 to 120°C, more preferably 110°C; and the reaction time is preferably 5 to 8 hours, more preferably 7 hours.

[0027] In this invention, in step S3, the molar ratio of the Schiff base triethoxysiloxane and the phosphorus-based flame retardant with a DOPO structure is preferably 1:2 to 3, more preferably 1:2; the reaction temperature is preferably 70 to 90°C, more preferably 80°C; and the reaction time is preferably 2 to 5 hours, more preferably 4 hours.

[0028] In this invention, in step S4, the molar ratio of diphenylsilanediol, phosphorus-containing triethoxysiloxane, and Schiff base triethoxysiloxane is preferably 1:1 to 3:1 to 3, more preferably 1:1:3; the reaction temperature is preferably 70 to 90°C, more preferably 80°C; and the reaction time is preferably 2 to 5 hours, more preferably 4 hours.

[0029] The present invention also provides the application of a reactive flame retardant or a reactive flame retardant prepared by the above preparation method in flame retardant finishing of nylon 6 fabrics.

[0030] This invention also provides a method for preparing UV-resistant flame-retardant nylon 6 fabric, comprising the following steps: Rosmarinic acid and reactive flame retardant are mixed to obtain a flame retardant solution; nylon 6 fabric is impregnated in the flame retardant solution, and then dried and cured in sequence to obtain UV-resistant flame-retardant nylon 6 fabric. The reactive flame retardant is one of the reactive flame retardants mentioned above or a reactive flame retardant prepared by the above preparation method.

[0031] In this invention, the preferred ratio of rosmarinic acid to reactive flame retardant is 0.1-0.2 mol:300 mL, and more preferably 0.1 mol:300 mL.

[0032] In this invention, the impregnation temperature is preferably 75~90℃, more preferably 80℃; the impregnation time is preferably 2~4h, more preferably 3h; the curing temperature is preferably 130~160℃, more preferably 150℃; and the curing time is preferably 2~10min, more preferably 5min.

[0033] The present invention also provides an UV-resistant and flame-retardant nylon 6 fabric prepared by the above preparation method.

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1

[0036] A method for preparing a reactive flame retardant includes the following steps: S1. Under a nitrogen atmosphere, using the Schiff base condensation reaction, 200 mL of anhydrous ethanol and 21.6 g (0.1 mol) of GLY were placed in a 500 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser and mixed thoroughly. After the mixture was uniformly dispersed, 67.1 g (0.3 mol) of APTES was slowly added to the above mixture, and the mixture was heated in an oil bath at 70 °C for 4 h to prepare the Schiff base triethoxysiloxane (GLY-TES).

[0037] S2. In a nitrogen atmosphere, 300 mL of DMF and 13.4 g (0.1 mol) of TDCA were placed in a 500 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser. After the solution was mixed evenly, 43.2 g (0.5 mol) of DOPO was slowly added, and the mixture was heated in an oil bath at 110 °C for condensation reaction for 7 h. After the reaction was completed and cooled, deionized water was added, and the organic solvent DMF was removed by vacuum filtration to obtain the crude product. The crude product was then dried under vacuum at 80 °C for 16 h to prepare a phosphorus-based flame retardant with a double DOPO structure (TDCA-DOPO).

[0038] S3. In a nitrogen atmosphere, 200 mL of anhydrous ethanol and 36.9 g (0.1 mol) of GLY-TES were placed in a 500 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser. After mixing evenly, 113.7 g (0.2 mol) of TDCA-DOPO was slowly added, and the mixture was heated in an oil bath at 80 °C to carry out a dehydration condensation reaction. After 4 h of reaction, phosphorus-containing triethoxysiloxane (GP-TES) was obtained.

[0039] S4. In a nitrogen atmosphere, 21.6 g (0.1 mol) of DPSD, 157.8 g (0.1 mol) of GP-TES, 36.9 g (0.1 mol) of GLY-TES and 200 mL of anhydrous ethanol were placed sequentially into a 500 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser. After mixing evenly, acetic acid was added dropwise to adjust the pH of the solution to 4. The reaction was carried out by heating in an oil bath at 80 °C. After reacting for 4 h, a phosphorus-containing Schiff base silica sol flame retardant (GPDSi flame retardant) was prepared.

[0040] Application Example 1

[0041] Finishing methods for UV-resistant and flame-retardant nylon 6 fabrics: 36.0 g (0.1 mol) of rosmarinic acid was added to 300 mL of the phosphorus-containing Schiff base silica sol flame retardant from Example 1. After thorough mixing, the nylon 6 fabric was completely immersed in the flame retardant solution and stirred at 80 °C for 3 h. After the reaction was complete, the fabric was removed, dried in a vacuum oven at 100 °C for 8 min, and then cured at 150 °C for 5 min to obtain UV-resistant flame-retardant nylon 6 fabric.

[0042] The original nylon 6 fabric had a limiting oxygen index (LOI) of 21.2%, while the UV-resistant and flame-retardant nylon 6 fabric achieved an LOI of 28.7% and passed the UL-94 V-0 level test. Simultaneously, the UPF value of the fabric increased from 34 to 91 before and after the treatment.

[0043] Example 2

[0044] A method for preparing a reactive flame retardant includes the following steps: S1. Under a nitrogen atmosphere, using the Schiff base condensation reaction, 200 mL of anhydrous ethanol and 21.6 g (0.1 mol) of GLY were placed in a 500 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser and mixed thoroughly. After the mixture was uniformly dispersed, 44.7 g (0.2 mol) of APTES was slowly added to the above mixture, and the mixture was heated in an oil bath at 70 °C for 4 h to prepare the Schiff base triethoxysiloxane (GLY-TES).

[0045] S2. In a nitrogen atmosphere, 300 mL of DMF and 13.4 g (0.1 mol) of TDCA were placed in a 500 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser. After the solution was mixed evenly, 25.9 g (0.3 mol) of DOPO was slowly added, and the mixture was heated in an oil bath at 110 °C for condensation reaction for 7 h. After the reaction was completed and cooled, deionized water was added, and the organic solvent DMF was removed by vacuum filtration to obtain the crude product. The crude product was then dried under vacuum at 80 °C for 16 h to prepare a phosphorus-based flame retardant with a double DOPO structure (TDCA-DOPO).

[0046] S3. In a nitrogen atmosphere, 200 mL of anhydrous ethanol and 36.9 g (0.1 mol) of GLY-TES were placed in a 500 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser. After mixing evenly, 113.7 g (0.2 mol) of TDCA-DOPO was slowly added, and the mixture was heated in an oil bath at 80 °C to carry out a dehydration condensation reaction. After 4 h of reaction, phosphorus-containing triethoxysiloxane (GP-TES) was obtained.

[0047] S4. In a nitrogen atmosphere, 21.6 g (0.1 mol) of DPSD, 157.8 g (0.1 mol) of GP-TES, 92.9 g (0.2 mol) of GLY-TES and 200 mL of anhydrous ethanol were placed in a 500 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser. After mixing evenly, acetic acid was added dropwise to adjust the pH of the solution to 4. The reaction was carried out by heating in an oil bath at 80 °C. After reacting for 4 h, a phosphorus-containing Schiff base silica sol flame retardant (GPDSi flame retardant) was prepared.

[0048] Application Example 2

[0049] Finishing methods for UV-resistant and flame-retardant nylon 6 fabrics: 72.1 g (0.2 mol) of rosmarinic acid was added to 300 mL of the phosphorus-containing Schiff base silica sol flame retardant from Example 2. After thorough mixing, the nylon 6 fabric was completely immersed in the flame retardant solution and stirred at 80 °C for 3 h. After the reaction was complete, the fabric was removed, dried in a vacuum oven at 100 °C for 8 min, and then cured at 150 °C for 5 min to obtain UV-resistant flame-retardant nylon 6 fabric.

[0050] The original nylon 6 fabric had a limiting oxygen index (LOI) of 21.2%, while the UV-resistant and flame-retardant nylon 6 fabric achieved an LOI of 29.8% and passed the UL-94 V-0 level test. Simultaneously, the UPF value of the fabric increased from 34 to 103 before and after the treatment.

[0051] Example 3

[0052] A method for preparing a reactive flame retardant includes the following steps: S1. Under a nitrogen atmosphere, using the Schiff base condensation reaction, 200 mL of anhydrous ethanol and 21.6 g (0.1 mol) of GLY were placed in a 500 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser and mixed thoroughly. After the mixture was uniformly dispersed, 89.4 g (0.4 mol) of APTES was slowly added to the above mixture, and the mixture was heated in an oil bath at 70 °C for 4 h to prepare the Schiff base triethoxysiloxane (GLY-TES).

[0053] S2. In a nitrogen atmosphere, 300 mL of DMF and 13.4 g (0.1 mol) of TDCA were placed in a 500 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser. After the solution was mixed evenly, 17.3 g (0.2 mol) of DOPO was slowly added, and the mixture was heated in an oil bath at 110 °C for condensation reaction for 7 h. After the reaction was completed and cooled, deionized water was added, and the organic solvent DMF was removed by vacuum filtration to obtain the crude product. The crude product was then dried under vacuum at 80 °C for 16 h to prepare a phosphorus-based flame retardant with a double DOPO structure (TDCA-DOPO).

[0054] S3. In a nitrogen atmosphere, 200 mL of anhydrous ethanol and 36.9 g (0.1 mol) of GLY-TES were placed in a 500 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser. After mixing evenly, 113.7 g (0.2 mol) of TDCA-DOPO was slowly added, and the mixture was heated in an oil bath at 80 °C to carry out a dehydration condensation reaction. After 4 h of reaction, phosphorus-containing triethoxysiloxane (GP-TES) was obtained.

[0055] S4. In a nitrogen atmosphere, 21.6 g (0.1 mol) of DPSD, 157.8 g (0.1 mol) of GP-TES, 139.4 g (0.3 mol) of GLY-TES and 200 mL of anhydrous ethanol were placed sequentially into a 500 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser. After mixing evenly, acetic acid was added dropwise to adjust the pH of the solution to 4. The reaction was carried out by heating in an oil bath at 80 °C. After reacting for 4 h, a phosphorus-containing Schiff base silica sol flame retardant (GPDSi flame retardant) was prepared.

[0056] Application Example 3

[0057] Finishing methods for UV-resistant and flame-retardant nylon 6 fabrics: 36.0 g (0.1 mol) of rosmarinic acid was added to 300 mL of the phosphorus-containing Schiff base silica sol flame retardant from Example 3. After mixing evenly, the nylon 6 fabric was completely immersed in the flame retardant solution and stirred at 80 °C for 3 h. After the reaction was completed, the fabric was removed, dried in a vacuum oven at 100 °C for 8 min, and then cured at 150 °C for 5 min to obtain UV-resistant flame-retardant nylon 6 fabric.

[0058] The original nylon 6 fabric had a limiting oxygen index (LOI) of 21.2%, while the UV-resistant and flame-retardant nylon 6 fabric achieved an LOI of 30.4% and passed the UL-94 V-0 level test. Simultaneously, the UPF value of the fabric increased from 34 to 86 before and after the treatment.

[0059] Example 4

[0060] A method for preparing a reactive flame retardant includes the following steps: S1. Under a nitrogen atmosphere, using the Schiff base condensation reaction, 200 mL of anhydrous ethanol and 21.6 g (0.1 mol) of GLY were placed in a 500 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser and mixed thoroughly. After the mixture was uniformly dispersed, 44.7 g (0.2 mol) of APTES was slowly added to the above mixture, and the mixture was heated in an oil bath at 70 °C for 4 h to prepare the Schiff base triethoxysiloxane (GLY-TES).

[0061] S2. In a nitrogen atmosphere, 300 mL of DMF and 13.4 g (0.1 mol) of TDCA were placed in a 500 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser. After the solution was mixed evenly, 34.6 g (0.4 mol) of DOPO was slowly added, and the mixture was heated in an oil bath at 110 °C for condensation reaction for 7 h. After the reaction was completed and cooled, deionized water was added, and the organic solvent DMF was removed by vacuum filtration to obtain the crude product. The crude product was then dried under vacuum at 80 °C for 16 h to prepare a phosphorus-based flame retardant with a double DOPO structure (TDCA-DOPO).

[0062] S3. In a nitrogen atmosphere, 200 mL of anhydrous ethanol and 36.9 g (0.1 mol) of GLY-TES were placed in a 500 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser. After mixing evenly, 113.7 g (0.2 mol) of TDCA-DOPO was slowly added, and the mixture was heated in an oil bath at 80 °C to carry out a dehydration condensation reaction. After 4 h of reaction, phosphorus-containing triethoxysiloxane (GP-TES) was obtained.

[0063] S4. In a nitrogen atmosphere, 21.6 g (0.1 mol) of DPSD, 236.7 g (0.15 mol) of GP-TES, 46.5 g (0.1 mol) of GLY-TES and 200 mL of anhydrous ethanol were placed sequentially into a 500 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser. After mixing thoroughly, acetic acid was added dropwise to adjust the pH of the solution to 4. The mixture was heated in an oil bath at 80 °C for 4 hours to prepare a phosphorus-containing Schiff base silica sol flame retardant (GPDSi flame retardant).

[0064] Application Example 4

[0065] Finishing methods for UV-resistant and flame-retardant nylon 6 fabrics: 72.1 g (0.2 mol) of rosmarinic acid was added to 300 mL of the phosphorus-containing Schiff base silica sol flame retardant from Example 4. After thorough mixing, the nylon 6 fabric was completely immersed in the flame retardant solution and stirred at 80 °C for 3 h. After the reaction was complete, the fabric was removed, dried in a vacuum oven at 100 °C for 8 min, and then cured at 150 °C for 5 min to obtain UV-resistant flame-retardant nylon 6 fabric.

[0066] The original nylon 6 fabric had a limiting oxygen index (LOI) of 21.2%, while the UV-resistant and flame-retardant nylon 6 fabric achieved an LOI of 29.1% and passed the UL-94 V-0 level test. Simultaneously, the UPF value of the fabric increased from 34 to 97 before and after the treatment.

[0067] Example 5

[0068] A method for preparing a reactive flame retardant includes the following steps: S1. Under a nitrogen atmosphere, using the Schiff base condensation reaction, 200 mL of anhydrous ethanol and 21.6 g (0.1 mol) of GLY were placed in a 500 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser and mixed thoroughly. After the mixture was uniformly dispersed, 44.7 g (0.2 mol) of APTES was slowly added to the above mixture, and the mixture was heated in an oil bath at 70 °C for 4 h to prepare the Schiff base triethoxysiloxane (GLY-TES).

[0069] S2. In a nitrogen atmosphere, 300 mL of DMF and 13.4 g (0.1 mol) of TDCA were placed in a 500 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser. After the solution was mixed evenly, 43.2 g (0.5 mol) of DOPO was slowly added, and the mixture was heated in an oil bath at 110 °C for condensation reaction for 7 h. After the reaction was completed and cooled, deionized water was added, and the organic solvent DMF was removed by vacuum filtration to obtain the crude product. The crude product was then dried under vacuum at 80 °C for 16 h to prepare a phosphorus-based flame retardant with a double DOPO structure (TDCA-DOPO).

[0070] S3. In a nitrogen atmosphere, 200 mL of anhydrous ethanol and 36.9 g (0.1 mol) of GLY-TES were placed in a 500 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser. After mixing evenly, 170.6 g (0.3 mol) of TDCA-DOPO was slowly added, and the mixture was heated in an oil bath at 80 °C to carry out a dehydration condensation reaction. After 4 h of reaction, phosphorus-containing triethoxysiloxane (GP-TES) was obtained.

[0071] S4. In a nitrogen atmosphere, 21.6 g (0.1 mol) of DPSD, 236.7 g (0.15 mol) of GP-TES, 92.9 g (0.2 mol) of GLY-TES and 200 mL of anhydrous ethanol were placed in a 500 mL three-necked flask equipped with a mechanical stirrer and a reflux condenser. After mixing evenly, acetic acid was added dropwise to adjust the pH of the solution to 4. The reaction was carried out by heating in an oil bath at 80 °C. After reacting for 4 h, a phosphorus-containing Schiff base silica sol flame retardant (GPDSi flame retardant) was prepared.

[0072] Application Example 5

[0073] Finishing methods for UV-resistant and flame-retardant nylon 6 fabrics: 72.1 g (0.2 mol) of rosmarinic acid was added to 300 mL of the phosphorus-containing Schiff base silica sol flame retardant from Example 5. After thorough mixing, the nylon 6 fabric was completely immersed in the flame retardant solution and stirred at 80 °C for 3 h. After the reaction was complete, the fabric was removed, dried in a vacuum oven at 100 °C for 8 min, and then cured at 150 °C for 5 min to obtain UV-resistant flame-retardant nylon 6 fabric.

[0074] The original nylon 6 fabric had a limiting oxygen index (LOI) of 21.2%, while the UV-resistant and flame-retardant nylon 6 fabric achieved an LOI of 29.7% and passed the UL-94 V-0 level test. Simultaneously, the UPF value of the fabric increased from 34 to 99 before and after the treatment.

[0075] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A reactive flame retardant characterized by, The structural formula of the reactive flame retardant is as follows: ； wherein R1 is , R2 is , R3 is .

2. The method for preparing a reactive flame retardant according to claim 1, characterized in that, Includes the following steps: S1. Under a nitrogen atmosphere, glyoxal, γ-aminopropyltriethoxysilane and anhydrous ethanol are mixed and reacted to obtain Schiff base triethoxysiloxane. S2. In a nitrogen atmosphere, terephthalaldehyde, DOPO, and N,N-dimethylformamide are mixed and reacted to obtain a phosphorus-based flame retardant with a bisDOPO structure; S3. In a nitrogen atmosphere, Schiff base triethoxysiloxane, a phosphorus-based flame retardant with a DOPO structure, and anhydrous ethanol are mixed and reacted to obtain phosphorus-containing triethoxysiloxane. S4. In a nitrogen atmosphere, diphenylsilanediol, phosphorus-containing triethoxysiloxane, Schiff base triethoxysiloxane, and anhydrous ethanol are mixed, and the pH value is adjusted to 3.5-4.5 with acetic acid. Then the reaction is carried out to obtain the reactive flame retardant.

3. The method for preparing a reactive flame retardant according to claim 2, characterized in that, In step S1, the molar ratio of glyoxal to γ-aminopropyltriethoxysilane is 1:2~4; the reaction temperature is 65~80℃; and the reaction time is 3~5h.

4. The method for preparing a reactive flame retardant according to claim 2, characterized in that, In step S2, the molar ratio of terephthalaldehyde to DOPO is 1:2~5; the reaction temperature is 100~120℃; and the reaction time is 5~8h.

5. The method for preparing a reactive flame retardant according to claim 2, characterized in that, In step S3, the molar ratio of the Schiff base triethoxysiloxane to the phosphorus-based flame retardant with a DOPO structure is 1:2~3; the reaction temperature is 70~90℃; and the reaction time is 2~5h.

6. The method for preparing a reactive flame retardant according to claim 2, characterized in that, In step S4, the molar ratio of diphenylsilanediol, phosphorus-containing triethoxysiloxane, and Schiff base triethoxysiloxane is 1:1~3:1~3; the reaction temperature is 70~90℃; and the reaction time is 2~5h.

7. The application of a reactive flame retardant as described in claim 1 or a reactive flame retardant prepared by any one of claims 2 to 6 in flame retardant finishing of nylon 6 fabrics.

8. A method for preparing an ultraviolet-resistant flame-retardant nylon 6 fabric, characterized in that, Includes the following steps: Rosmarinic acid and reactive flame retardant are mixed to obtain a flame retardant solution; Nylon 6 fabric is immersed in a flame retardant solution, and then dried and cured sequentially to obtain UV-resistant flame-retardant nylon 6 fabric. The reactive flame retardant is a reactive flame retardant as described in claim 1 or a reactive flame retardant prepared by the preparation method described in any one of claims 2 to 6.

9. The method for preparing an UV-resistant flame-retardant nylon 6 fabric according to claim 8, characterized in that, The impregnation temperature is 75~90℃; the impregnation time is 2~4h; the curing temperature is 130~160℃; and the curing time is 2~10min.

10. A UV-resistant flame-retardant nylon 6 fabric prepared by the method described in claim 8 or 9.

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