Flame-retardant nylon material, preparation method thereof and magic tape

Abstract

The invention relates to the technical field of functional magic tapes, in particular to a flame-retardant nylon material, a preparation method of the flame-retardant nylon material and a magic tape. The flame-retardant nylon material comprises the following raw materials in parts by mass: 60-80 parts of nylon 66, 10-20 parts of a multifunctional composite flame retardant and 0.2-1.0 part of a stabilizer, the multifunctional composite flame retardant is prepared by compounding and blending a zinc oxide-lignin composite material and piperazine pyrophosphate. The magic tape prepared from the flame-retardant nylon material disclosed by the invention has excellent flame retardance and ultraviolet resistance.

Description

Technical Field

[0001] The present application relates to the technical field of functional hook and loop tape, and more specifically, to a flame-retardant nylon material, a preparation method thereof, and a hook and loop tape. Background Art

[0002] Velcro, also known as hook and loop fasteners, is a commonly used fastening material. It typically consists of a hook surface and a loop surface. When pressed, the hooks on the loop surface grasp the loops on the loop surface, creating a strong bond. This bond allows for easy separation and repeated use, making it widely used in clothing, footwear, luggage, household items, and other fields.

[0003] At present, commonly used Velcro is basically made of nylon, but the flame retardant performance of nylon material is poor. When a fire occurs, it is easy to cause the fire to spread and cause a larger-scale fire accident. Therefore, there is an urgent need for a nylon material with excellent flame retardant properties for use in Velcro. Summary of the Invention

[0004] In order to improve the defect of poor flame retardancy of conventional nylon hook and loop tape, the present application provides a flame retardant nylon material, a preparation method thereof, and hook and loop tape.

[0005] In a first aspect, the present application provides a flame retardant nylon material, which adopts the following technical solution: A flame-retardant nylon material comprises the following raw materials in parts by mass: 60-80 parts of nylon 66, 10-20 parts of a multifunctional composite flame retardant, and 0.2-1.0 parts of a stabilizer; the multifunctional composite flame retardant is obtained by compositely blending a zinc oxide-lignin composite material with piperazine pyrophosphate.

[0006] Piperazine pyrophosphate is a new type of three-source, environmentally friendly flame retardant with good flame retardant effects in both the condensed phase and the gas phase. However, the phosphorus and carbon content in its structure is low, while the lignin skeleton structure contains a large number of aromatic groups. The carbon content of up to 60% makes it exhibit excellent carbonization properties after pyrolysis. Zinc oxide has a catalytic carbonization effect. Therefore, when the zinc oxide-lignin composite material is used in combination with piperazine pyrophosphate, a significant flame retardant effect will be obtained.

[0007] In addition, since nylon materials contain a large number of amide groups, these groups can easily cause chemical bonds to break after being exposed to ultraviolet rays, thereby destroying the molecular structure of nylon and degrading its performance.

[0008] Zinc oxide has excellent UV shielding and absorption capabilities, but it also suffers from strong polarity, easy agglomeration, and poor compatibility with polymers. In this application, lignin and zinc oxide are modified through a hydrothermal method to form an organic-inorganic hybrid, effectively enhancing the compatibility of zinc oxide in polymers. Furthermore, the conjugated carbonyl groups on the lignin side chains have strong UV absorption in the 280-380nm UV region. Therefore, when lignin and zinc oxide are used together, the flame-retardant nylon material will have even better UV resistance.

[0009] Preferably, the mass ratio of the zinc oxide-lignin composite material to piperazine pyrophosphate is (1-2): (1-2).

[0010] When the zinc oxide-lignin composite material and piperazine pyrophosphate adopt the above mass ratio, the prepared flame retardant nylon material will have better flame retardant properties and UV resistance.

[0011] Preferably, the preparation method of the zinc oxide-lignin composite material comprises the following steps: S1. First, dissolve zinc nitrate hexahydrate in deionized water to obtain a zinc nitrate solution; dissolve hexamethylenetetramine in deionized water to obtain an additive solution; mix the zinc nitrate solution and the additive solution to obtain a zinc oxide precursor solution; S2. Mix the zinc oxide precursor solution with lignin, then put it into a hydrothermal kettle, hydroheat it at 100-150° C. for 4-6 hours, and finally freeze-dry it to obtain a zinc oxide-lignin composite material.

[0012] Preferably, the preparation method of the zinc oxide-lignin composite material comprises the following steps: S1. First, dissolve 3-4 g of zinc nitrate hexahydrate in 100 ml of deionized water to obtain a zinc nitrate solution; dissolve 1-2 g of hexamethylenetetramine in 100 ml of deionized water to obtain an additive solution; mix the zinc nitrate solution and the additive solution to obtain a zinc oxide precursor solution; S2. Mix 20-30 ml of zinc oxide precursor solution with 100-200 mg of lignin, then put them into a hydrothermal kettle, hydroheat at 100-150° C. for 4-6 hours, and finally freeze-dry to obtain a zinc oxide-lignin composite material.

[0013] Preferably, the surface of the zinc oxide-lignin composite material is subjected to a hydrophobic treatment.

[0014] Nylon has strong hygroscopicity, so when the nylon material is washed multiple times, the multifunctional composite flame retardant is likely to be eluted with water. After the zinc oxide-lignin composite material is hydrophobized, the zinc oxide-lignin composite material can be more stable in the nylon material, indirectly improving the flame retardant properties and UV resistance of the flame-retardant nylon material.

[0015] Preferably, the hydrophobic surface treatment step of the zinc oxide-lignin composite material is: first, the zinc oxide-lignin composite material is mixed with n-hexane, then 1H,1H,2H,2H-perfluorodecyltrichlorosilane is added and stirred continuously, and then centrifuged, washed and dried to obtain a hydrophobic zinc oxide-lignin composite material.

[0016] Preferably, the mass ratio of the zinc oxide-lignin composite material, n-hexane and 1H,1H,2H,2H-perfluorodecyltrichlorosilane is (4-10): (40-50): (0.4-0.6).

[0017] Preferably, the stabilizer is a calcium zinc stabilizer or a barium zinc stabilizer.

[0018] In a second aspect, the present application provides a method for preparing a flame retardant nylon material, which adopts the following technical solution: A method for preparing a flame-retardant nylon material comprises the following steps: firstly, mixing nylon 66, a multifunctional composite flame retardant and a stabilizer; then transferring the mixture to a twin-screw extruder; melt-mixing and extruding the mixture at 210-250° C.; cooling, granulating and drying the mixture to obtain the flame-retardant nylon material.

[0019] In a third aspect, the present application provides a hook and loop tape, which adopts the following technical solution: A Velcro is obtained by processing the flame-retardant nylon material.

[0020] In summary, this application has the following beneficial effects: 1. Piperazine pyrophosphate is a new type of three-source integrated environmentally friendly flame retardant with good flame retardant effects in both the condensed phase and the gas phase. However, the phosphorus and carbon content in its structure is low, while the lignin skeleton structure contains a large number of aromatic groups. The carbon content of up to 60% makes it exhibit excellent carbonization performance after pyrolysis. Zinc oxide has a catalytic carbonization effect. Therefore, when the zinc oxide-lignin composite material is used in combination with piperazine pyrophosphate, a significant flame retardant effect will be obtained.

[0021] 2. Zinc oxide has excellent UV shielding and absorption capabilities, but it also has drawbacks such as strong polarity, easy agglomeration, and poor compatibility with polymers. In this application, lignin and zinc oxide are modified through an organic-inorganic hybridization process using a hydrothermal method, effectively enhancing the compatibility of zinc oxide in polymers through the use of lignin. Furthermore, the conjugated carbonyl groups on the lignin side chains have strong UV absorption in the 280-380nm UV region. Therefore, when lignin and zinc oxide are used together, the flame-retardant nylon material will have even better UV resistance.

[0022] 3. Nylon has strong hygroscopicity. Therefore, after the nylon material is washed many times, the multifunctional composite flame retardant is likely to be precipitated with water. After the zinc oxide-lignin composite material is hydrophobized, the zinc oxide-lignin composite material can be more stable in the nylon material, indirectly improving the flame retardant properties and UV resistance of the flame retardant nylon material. DETAILED DESCRIPTION

[0023] The present application is further described in detail below in conjunction with Examples 1 to 4 and Comparative Examples 1 to 3.

[0024] raw material Nylon 66 DuPont 12T NC010; Piperazine pyrophosphate CAS: 66034-17-1; Zinc nitrate hexahydrate CAS: 10196-18-6; Hexamethylenetetramine CAS: 100-97-0; Lignin CAS: 8068-03-9; n-Hexane CAS: 110-54-3; 1H,1H,2H,2H-Perfluorodecyltrichlorosilane CAS: 78560-44-8; Calcium zinc stabilizer CZ-113.

[0025] Example 1 A flame-retardant nylon material includes the following raw materials: 70g of nylon 66, 15g of a multifunctional composite flame retardant, and 0.5g of a calcium-zinc stabilizer. The multifunctional composite flame retardant is obtained by blending a zinc oxide-lignin composite material with piperazine pyrophosphate, and the mass ratio of the zinc oxide-lignin composite material to the piperazine pyrophosphate is 1:1.

[0026] The preparation method of the flame-retardant nylon material comprises the following steps: firstly, mixing nylon 66, a multifunctional composite flame retardant and a stabilizer, then transferring the mixture into a twin-screw extruder, melt-mixing and extruding the mixture at 240°C, cooling, granulating and drying the mixture to obtain the flame-retardant nylon material.

[0027] Flame retardant nylon material is used to process Velcro.

[0028] The preparation method of the zinc oxide-lignin composite material comprises the following steps: S1. First, dissolve 3.5 g of zinc nitrate hexahydrate in 100 ml of deionized water to obtain a zinc nitrate solution; dissolve 1.5 g of hexamethylenetetramine in 100 ml of deionized water to obtain an additive solution; mix the zinc nitrate solution and the additive solution to obtain a zinc oxide precursor solution; S2. Mix 25 ml of zinc oxide precursor solution with 150 mg of lignin, then put them into a hydrothermal kettle, hydroheat at 130° C. for 5 h, and finally freeze-dry to obtain a zinc oxide-lignin composite material.

[0029] Example 2 A flame-retardant nylon material includes the following raw materials: 70g of nylon 66, 15g of a multifunctional composite flame retardant, and 0.5g of a calcium-zinc stabilizer. The multifunctional composite flame retardant is obtained by blending a zinc oxide-lignin composite material with piperazine pyrophosphate, and the mass ratio of the zinc oxide-lignin composite material to the piperazine pyrophosphate is 2:1.

[0030] The preparation method of the flame-retardant nylon material comprises the following steps: firstly, mixing nylon 66, a multifunctional composite flame retardant and a stabilizer, then transferring the mixture into a twin-screw extruder, melt-mixing and extruding the mixture at 240°C, cooling, granulating and drying the mixture to obtain the flame-retardant nylon material.

[0031] Flame retardant nylon material is used to process Velcro.

[0032] The preparation method of the zinc oxide-lignin composite material comprises the following steps: S1. First, dissolve 3.5 g of zinc nitrate hexahydrate in 100 ml of deionized water to obtain a zinc nitrate solution; dissolve 1.5 g of hexamethylenetetramine in 100 ml of deionized water to obtain an additive solution; mix the zinc nitrate solution and the additive solution to obtain a zinc oxide precursor solution; S2. Mix 25 ml of zinc oxide precursor solution with 150 mg of lignin, then put them into a hydrothermal kettle, hydroheat at 130° C. for 5 h, and finally freeze-dry to obtain a zinc oxide-lignin composite material.

[0033] Example 3 A flame-retardant nylon material includes the following raw materials: 70g of nylon 66, 15g of a multifunctional composite flame retardant, and 0.5g of a calcium-zinc stabilizer. The multifunctional composite flame retardant is obtained by blending a zinc oxide-lignin composite material with piperazine pyrophosphate, and the mass ratio of the zinc oxide-lignin composite material to the piperazine pyrophosphate is 1:2.

[0034] The preparation method of the flame-retardant nylon material comprises the following steps: firstly, mixing nylon 66, a multifunctional composite flame retardant and a stabilizer, then transferring the mixture into a twin-screw extruder, melt-mixing and extruding the mixture at 240°C, cooling, granulating and drying the mixture to obtain the flame-retardant nylon material.

[0035] Flame retardant nylon material is used to process Velcro.

[0036] The preparation method of the zinc oxide-lignin composite material comprises the following steps: S1. First, dissolve 3.5 g of zinc nitrate hexahydrate in 100 ml of deionized water to obtain a zinc nitrate solution; dissolve 1.5 g of hexamethylenetetramine in 100 ml of deionized water to obtain an additive solution; mix the zinc nitrate solution and the additive solution to obtain a zinc oxide precursor solution; S2. Mix 25 ml of zinc oxide precursor solution with 150 mg of lignin, then put them into a hydrothermal kettle, hydroheat at 130° C. for 5 h, and finally freeze-dry to obtain a zinc oxide-lignin composite material.

[0037] Example 4 A flame-retardant nylon material includes the following raw materials: 70g of nylon 66, 15g of a multifunctional composite flame retardant, and 0.5g of a calcium-zinc stabilizer. The multifunctional composite flame retardant is obtained by blending a zinc oxide-lignin composite material with piperazine pyrophosphate, and the mass ratio of the zinc oxide-lignin composite material to the piperazine pyrophosphate is 1:1.

[0038] The preparation method of the flame-retardant nylon material comprises the following steps: firstly, mixing nylon 66, a multifunctional composite flame retardant and a stabilizer, then transferring the mixture into a twin-screw extruder, melt-mixing and extruding the mixture at 240°C, cooling, granulating and drying the mixture to obtain the flame-retardant nylon material.

[0039] Flame retardant nylon material is used to process Velcro.

[0040] The preparation method of the zinc oxide-lignin composite material comprises the following steps: S1. First, dissolve 3.5 g of zinc nitrate hexahydrate in 100 ml of deionized water to obtain a zinc nitrate solution; dissolve 1.5 g of hexamethylenetetramine in 100 ml of deionized water to obtain an additive solution; mix the zinc nitrate solution and the additive solution to obtain a zinc oxide precursor solution; S2, 25 ml of zinc oxide precursor solution was mixed with 150 mg of lignin, and then placed in a hydrothermal kettle, hydroheated at 130° C. for 5 h, and finally freeze-dried to obtain a zinc oxide-lignin composite material; Then the surface of the zinc oxide-lignin composite material was subjected to hydrophobic treatment; The hydrophobic surface treatment steps of the zinc oxide-lignin composite material are as follows: first, the zinc oxide-lignin composite material is mixed with n-hexane, then 1H,1H,2H,2H-perfluorodecyltrichlorosilane is added and the mixture is continuously stirred, and then centrifuged, washed and dried to obtain the hydrophobic zinc oxide-lignin composite material; The mass ratio of zinc oxide-lignin composite material, n-hexane and 1H,1H,2H,2H-perfluorodecyltrichlorosilane is 7:45:0.5.

[0041] Comparative Example 1 A nylon material includes the following raw materials: 70g of nylon 66 and 0.5g of a calcium zinc stabilizer.

[0042] The preparation method of nylon material comprises the following steps: firstly, mixing nylon 66 and a stabilizer, then transferring the mixture into a twin-screw extruder, melting and kneading the mixture at 240°C, extruding the mixture, cooling, granulating and drying the mixture to obtain the nylon material.

[0043] Flame retardant nylon material is used to process Velcro.

[0044] Comparative Example 2 A flame-retardant nylon material comprises the following raw materials: 70g of nylon 66, 15g of piperazine pyrophosphate and 0.5g of a calcium zinc stabilizer.

[0045] The preparation method of the flame-retardant nylon material comprises the following steps: firstly, mixing nylon 66, piperazine pyrophosphate and a stabilizer, then transferring the mixture into a twin-screw extruder, melt-mixing and extruding the mixture at 240°C, cooling, granulating and drying the mixture to obtain the flame-retardant nylon material.

[0046] Flame retardant nylon material is used to process Velcro.

[0047] Comparative Example 3 A flame-retardant nylon material includes the following raw materials: 70g of nylon 66, 15g of a multifunctional composite flame retardant, and 0.5g of a calcium-zinc stabilizer. The multifunctional composite flame retardant is obtained by compositely blending lignin and piperazine pyrophosphate, and the mass ratio of lignin to piperazine pyrophosphate is 1:1.

[0048] The preparation method of the flame-retardant nylon material comprises the following steps: firstly, mixing nylon 66, a multifunctional composite flame retardant and a stabilizer, then transferring the mixture into a twin-screw extruder, melt-mixing and extruding the mixture at 240°C, cooling, granulating and drying the mixture to obtain the flame-retardant nylon material.

[0049] Flame retardant nylon material is used to process Velcro.

[0050] Performance testing 1. Flame retardant performance test Three samples were taken from each of Examples 1 to 3 and Comparative Examples 1 to 3, and the oxygen index of the samples was tested according to GB / T 2406.2-2009 “Determination of Combustion Behavior of Plastics by Oxygen Index Method”, and the average value was taken.

[0051] 2. Anti-ultraviolet performance test Six samples were taken from Example 1, Comparative Example 1, and Comparative Example 3, respectively. The original tensile strength of three of the samples was then tested in accordance with GB / T 32363.2-2015 "Plastics polyamide molding and extrusion materials - Part 2 - Preparation of specimens and determination of properties". The test data are shown in Table 1.

[0052] The remaining three samples were then subjected to UV aging in accordance with GB / T 16422.3-2014 "Plastics Laboratory Light Source Exposure Test Methods", and the tensile strength of the UV-aged samples was tested again in accordance with GB / T 32363.2-2015 "Plastics Polyamide Molding and Extrusion Materials Part 2: Preparation of Specimens and Determination of Properties".

[0053] Finally, the aging value is calculated, aging value = aging tensile strength / original tensile strength × 100%. The test data are shown in Table 2.

[0054] 3. Hydrophobic performance test Nine samples were taken from Example 1 and Example 4 respectively, and then placed in deionized water for mixing and stirring for 48 hours, and then dried. Finally, the oxygen index and aging value of the samples were tested with reference to the above-mentioned flame retardant performance test and UV resistance test. The test data are shown in Table 3.

[0055] Table 1 Flame retardant performance test table of Example 1-Example 3 and Comparative Example 1-Comparative Example 3 Table 2 Anti-ultraviolet performance of Example 1, Comparative Example 1 and Comparative Example 3 Table 4 Comparison of hydrophobic properties of Example 1 and Example 4 Referring to Example 1 and Comparative Examples 1-3, in conjunction with Table 1, it can be seen that the oxygen index of Comparative Example 2 is significantly improved compared to Comparative Example 1, indicating that the addition of piperazine pyrophosphate can effectively improve the flame retardant properties of nylon materials. The oxygen index of Comparative Example 3 is further improved compared to Comparative Example 2, indicating that the combination of piperazine pyrophosphate and lignin can produce a nylon material with even better flame retardant properties. The oxygen index of Example 1 is further improved compared to Comparative Example 3, indicating that the addition of nano-zinc oxide can further improve the flame retardant properties of nylon materials.

[0056] The reason is that piperazine pyrophosphate is a new type of three-source environmentally friendly flame retardant with good flame retardant effects in both the condensed phase and the gas phase. However, the content of phosphorus and carbon elements in its structure is low, while the lignin skeleton structure contains a large number of aromatic groups. The carbon content of up to 60% makes it exhibit excellent carbonization properties after pyrolysis, and zinc oxide has a catalytic carbonization effect. Therefore, when the zinc oxide-lignin composite material is used in combination with piperazine pyrophosphate, a significant flame retardant effect will be obtained.

[0057] With reference to Examples 1 to 3 and in combination with Table 1, it can be seen that Example 1 has a higher oxygen index than Example 2 and Example 3. This indicates that when the zinc oxide-lignin composite material and piperazine pyrophosphate adopt the mass ratio of Example 1, the prepared nylon material will have better flame retardant properties.

[0058] In addition, referring to Example 1, Comparative Example 1 and Comparative Example 3 and combining with Table 2, it can be seen that the aging value of Comparative Example 3 is significantly improved compared with Comparative Example 1, and the aging value of Example 1 is further improved compared with Comparative Example 3. This shows that the loading of lignin and nano-zinc oxide can further improve the UV resistance of nylon materials.

[0059] The reason is that nylon materials contain a large number of amide groups, which can easily cause chemical bonds to break when exposed to ultraviolet rays, thereby destroying the molecular structure of nylon and reducing its performance.

[0060] Zinc oxide has excellent UV shielding and absorption capabilities, but it also suffers from strong polarity, easy agglomeration, and poor compatibility with polymers. In this application, lignin and zinc oxide are modified through a hydrothermal method to form an organic-inorganic hybrid, effectively enhancing the compatibility of zinc oxide in polymers. Furthermore, the conjugated carbonyl groups on the lignin side chains have strong UV absorption in the 280-380nm UV region. Therefore, when lignin and zinc oxide are used together, the flame-retardant nylon material will have even better UV resistance.

[0061] Referring to Example 1 and Example 4 and combining with Table 3, it can be seen that compared with Example 1, the oxygen index after washing and the aging value after washing of Example 4 are relatively higher, which shows that the hydrophobic treatment of the surface of the zinc oxide-lignin composite material can indirectly improve the flame retardant properties and UV resistance of the nylon material after washing.

[0062] The reason is that nylon has strong hygroscopicity. Therefore, after the nylon material is washed many times, the multifunctional composite flame retardant is likely to be eluted with water. After the zinc oxide-lignin composite material is hydrophobized, the zinc oxide-lignin composite material can be more stable in the nylon material, indirectly improving the flame retardant properties and UV resistance of the flame-retardant nylon material.

[0063] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A flame retardant nylon material, characterized in that: The invention comprises the following raw materials in parts by mass: 60-80 parts of nylon 66, 10-20 parts of a multifunctional composite flame retardant and 0.2-1.0 parts of a stabilizer; the multifunctional composite flame retardant is obtained by compositely blending a zinc oxide-lignin composite material and piperazine pyrophosphate.

2. The flame-retardant nylon material according to claim 1, characterized in that: The mass ratio of the zinc oxide-lignin composite material to piperazine pyrophosphate is (1-2): (1-2).

3. The flame retardant nylon material according to claim 1, characterized in that: The preparation method of the zinc oxide-lignin composite material comprises the following steps: S1. First, dissolve zinc nitrate hexahydrate in deionized water to obtain a zinc nitrate solution; dissolve hexamethylenetetramine in deionized water to obtain an additive solution; mix the zinc nitrate solution and the additive solution to obtain a zinc oxide precursor solution; S2. Mix the zinc oxide precursor solution with lignin, then put it into a hydrothermal kettle, hydroheat it at 100-150° C. for 4-6 hours, and finally freeze-dry it to obtain a zinc oxide-lignin composite material.

4. The flame retardant nylon material according to claim 1, characterized in that: The preparation method of the zinc oxide-lignin composite material comprises the following steps: S1. First, dissolve 3-4 g of zinc nitrate hexahydrate in 100 ml of deionized water to obtain a zinc nitrate solution; dissolve 1-2 g of hexamethylenetetramine in 100 ml of deionized water to obtain an additive solution; mix the zinc nitrate solution and the additive solution to obtain a zinc oxide precursor solution; S2. Mix 20-30 ml of zinc oxide precursor solution with 100-200 mg of lignin, then put them into a hydrothermal kettle, hydroheat at 100-150° C. for 4-6 hours, and finally freeze-dry to obtain a zinc oxide-lignin composite material.

5. The flame retardant nylon material according to claim 1, characterized in that: The surface of the zinc oxide-lignin composite material is subjected to hydrophobic treatment.

6. The flame retardant nylon material according to claim 5, characterized in that: The hydrophobic surface treatment steps of the zinc oxide-lignin composite material are: first, mixing the zinc oxide-lignin composite material with n-hexane, then adding 1H,1H,2H,2H-perfluorodecyltrichlorosilane and continuing to stir, and then centrifugally washing and drying to obtain the hydrophobic zinc oxide-lignin composite material.

7. The flame retardant nylon material according to claim 6, characterized in that: The mass ratio of the zinc oxide-lignin composite material, n-hexane and 1H,1H,2H,2H-perfluorodecyltrichlorosilane is (4-10): (40-50): (0.4-0.6).

8. The flame retardant nylon material according to claim 6, characterized in that: The stabilizer is a calcium zinc stabilizer or a barium zinc stabilizer.

9. A method for preparing the flame-retardant nylon material according to any one of claims 1 to 8, characterized in that: The steps are as follows: first, nylon 66, a multifunctional composite flame retardant and a stabilizer are mixed, and then transferred to a twin-screw extruder, melt-mixed and extruded at 210-250° C., cooled, granulated and dried to obtain a flame-retardant nylon material.

10. A Velcro, characterized in that: The flame retardant nylon material is obtained by processing the flame retardant nylon material according to any one of claims 1 to 8.

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