Nylon industrial yarn for airbag and method for manufacturing the same

Abstract

The application belongs to the technical field of nylon industrial yarn, and particularly relates to a nylon industrial yarn for airbag and a preparation method thereof. The preparation method of the nylon industrial yarn is as follows: taking nylon 66 salt and benzotriazole-phosphate derivative as raw materials, under the action of sodium hypophosphite, polycondensation is carried out to obtain modified nylon 66 chip, and then the nylon industrial yarn is prepared through melt spinning; the nylon industrial yarn is prepared by one-step direct polymerization, which can effectively avoid the problem of the decline of the comprehensive performance of the finished product nylon 66 caused by the flame-retardant modification, and the preparation process is simple and convenient for production; the prepared nylon industrial yarn has good strength, aging resistance and flame retardance, and has great market application value in the field of automobile airbag.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of nylon industrial yarns, and particularly relates to a nylon industrial yarn for airbags and a preparation method thereof. BACKGROUND

[0002] Nylon 66, also known as polyamide-66 or polyhexamethylene adipamide, is obtained by polycondensation of hexamethylene diamine and adipic acid. Nylon 66 has the advantages of high strength, good rigidity, impact resistance, oil and chemical resistance, wear resistance and self-lubrication, and is particularly excellent in hardness, rigidity, heat resistance and creep performance, and is widely used in cord fabric, tires, air tires, special tires, airbag yarns, parachutes, military tents, conveyor belts, industrial filter cloth, ropes, safety belts and military products. In addition to the above advantages, the airbag yarn also needs to have certain flame retardant properties. After the airbag body is rapidly deployed, it will come into contact with the human face skin, preventing the flame from further igniting the airbag when the car catches fire, thereby improving the safety of the airbag.

[0003] Patent No. 201310504440.6 discloses a nylon 66 monofilament and a production method thereof. The nylon 66 monofilament has a diameter of 0.02-0.07 mm, a heat shrinkage rate of less than or equal to 10%, a breaking elongation of 30-40%, and a strength of greater than or equal to 5.5 cN / dtex. The nylon 66 monofilament has the advantages of high strength, high breaking elongation and low heat shrinkage rate. Patent No. 202210286523.1 discloses a low-cost bio-based composite fiber and a preparation method and application thereof. The preparation method comprises: preparing nylon 66 chips and nylon 56 chips respectively; and melt-extruding the nylon 66 chips and the nylon 56 chips to form a composite yarn, so that the nylon 56 forms a core layer and the nylon 66 forms a skin layer, thereby obtaining a low-cost bio-based composite fiber. The low-cost bio-based composite fiber has mechanical properties equivalent to those of nylon 66 fiber and better softness, and can be applied in the field of automobile airbags. The nylon 66 materials prepared by the above methods do not involve improvement of flame retardant properties, which results in poor use effect in special scenarios. SUMMARY

[0004] The application aims to solve the problems in the prior art, and provides a nylon industrial yarn for airbags and a preparation method thereof. The nylon industrial yarn for airbags is simple to prepare and easy to produce, has good strength, aging resistance and flame retardant properties, and has great market application value in the field of automobile airbags.

[0005] The technical scheme adopted by the application to achieve the above-mentioned purpose is as follows.

[0006] A preparation method of a nylon industrial yarn for airbags comprises the following steps.

[0007] S1, the nylon 66 salt is prepared into a 40-50% salt aqueous solution, benzotriazole-phosphate derivative, sodium hypophosphite are added, under nitrogen protection, the temperature is raised to 230-240℃, the pressure is raised to 2.0-2.5MPa, the reaction is carried out for 2-3h, most of the water is removed, and a prepolymer is obtained;

[0008] S2, the prepolymer obtained in step S1 is heated to 270-280℃, the pressure is reduced to 0.3-0.5MPa, the reaction is carried out for 2-4h, the pressure is reduced to normal, the melt is cast, granulated and dried to obtain modified nylon 66 chips;

[0009] S3, the modified nylon 66 chips are added to a spinning screw extruder, the temperature and pressure are set, the melt spinning is extruded from the spinneret hole of the spinneret, the side blowing cooling is used, the oiling, stretching and winding are carried out to obtain nylon industrial yarns;

[0010] Further, the weight ratio of the nylon 66 salt, benzotriazole-phosphate derivative and sodium hypophosphite in step S1 is 100:5-10:0.05-0.1.

[0011] Further, the temperature of the spinning screw extruder in step S3 is respectively: zone 1 260-270℃, zone 2 270-280℃, zone 3 280-290℃, zone 4 290-300℃, zone 5 290-300℃; the pressure of the spinning screw extruder is 8-10MPa; the blowing rate is 4-5m / min, the cooling temperature is 15-20℃; the pre-stretching temperature is 80-90℃, the stretching temperature is 110-120℃, the stretching multiple is 4-5; the winding speed is 1000-1500m / min.

[0012] Further, the chemical structural formula of the benzotriazole-phosphate derivative is:

[0013]

[0014] The preparation method of the benzotriazole-phosphate derivative is: compound 3, sodium hydroxide are added into a 50-60% ethanol aqueous solution, ammonia gas is introduced, the reaction pressure is 0.4-0.6MPa when the ammonia gas is added, the reaction is carried out for 3-5h to obtain the benzotriazole-phosphate derivative; the molar ratio of the compound 3 and sodium hydroxide is 1:0.8-1; the chemical structural formula of the compound 3 is:

[0015]

[0016] Further, the preparation method of the compound 3 is:

[0017] (1) benzotriazole, 1-chlorobutanol, sodium hydroxide are added into N, N-dimethylformamide solution, and the temperature is raised to 100-110 DEG C, and the reaction is carried out for 2-4 h to obtain compound 1, and the chemical structural formula is as follows:

[0018]

[0019] (2) compound 1, a catalyst are added into chloroform solution, and under stirring, epichlorohydrin is added dropwise, after dropwise addition, the temperature is raised to 50-60 DEG C, and the reaction is carried out for 4-6 h to obtain compound 2, and the chemical structural formula is as follows:

[0020]

[0021] (3) compound 2 is added into chloroform solution, and dimethyl phosphite is added dropwise, after dropwise addition, the temperature is raised to 50-60 DEG C, and the reaction is carried out for 3-4 h to obtain compound 3.

[0022] Further, in step (1), the molar ratio of benzotriazole, 1-chlorobutanol, sodium hydroxide is 1:1.1-1.2:2-2.5; in step (2), the catalyst is one or a mixture of several of boron trifluoride, ferric chloride, aluminum chloride and zinc chloride, and the molar ratio of compound 1, epichlorohydrin, catalyst is 1:1.1-1.2:0.2-0.5; in step (3), the molar ratio of compound 2, dimethyl phosphite is 1:1.1-1.2.

[0023] The application provides a nylon industrial yarn for airbag, which is prepared by the preparation method of the nylon industrial yarn.

[0024] The application also provides a use of the nylon industrial yarn for airbag, and the prepared nylon industrial yarn can be used for preparing automobile airbag.

[0025] The application has the following beneficial effects:

[0026] The application takes benzotriazole as a starting material, first reacts with 1-chlorobutanol to introduce a hydroxyl group, and then sequentially reacts with epichlorohydrin, dimethyl phosphate and ammonia to obtain a benzotriazole-phosphate ester derivative. The prepared benzotriazole-phosphate ester derivative belongs to a nitrogen-phosphorus flame retardant, and has good flame retardant effect when applied to the preparation process of nylon industrial yarn. On the one hand, the benzotriazole-phosphate ester derivative containing phosphate groups and benzotriazole groups can decompose to produce P-O, P=O and nitrides when burning, and then react with free radicals generated by the decomposition of nylon industrial yarn and produce a gas barrier layer to inhibit the formation and spread of flames. Moreover, a carbon layer can be formed on the surface of the nylon industrial yarn to prevent the nylon industrial yarn from contacting oxygen, thereby greatly improving the flame retardant performance of the nylon industrial yarn. On the other hand, the rigid benzotriazole group can improve the breaking strength of the nylon industrial yarn and has certain light stability, can eliminate or slow down photochemical reactions, and prevent or delay the photoaging process of the nylon industrial yarn, thereby enhancing the aging resistance of the nylon industrial yarn. At the same time, the amino group in the molecular structure of the benzotriazole-phosphate ester derivative can participate in the polycondensation of nylon 66 salt, thereby improving the compatibility and binding force of the benzotriazole-phosphate ester derivative and the nylon 66 salt polycondensate, and improving the comprehensive performance of the final product nylon industrial yarn.

[0027] The application takes nylon 66 salt and benzotriazole-phosphate ester derivative as raw materials, and directly polymerizes to prepare nylon industrial yarn by one-step method, which can effectively avoid the problem of flame-retardant modification of finished nylon 66, causing the decline of its comprehensive performance. The preparation process of the nylon industrial yarn provided by the application is simple and convenient for production, and the prepared nylon industrial yarn has good strength, aging resistance and flame retardant performance, and has great market application value in the field of automobile safety airbags. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the application.

[0029] Nylon 66 salt CAS No. 3323-53-3, purchased from Guangdong Wengjiang Chemical Reagent Co., Ltd.; Sodium hypophosphite CAS No. 7681-53-0; Sodium hydroxide CAS No. 1310-73-2; Ammonia gas CAS No. 7664-41-7; 1-Chlorobutanol CAS No. 928-51-8; Epichlorohydrin CAS No. 106-89-8; Boron trifluoride CAS No. 7637-07-2; Dimethyl phosphite CAS No. 868-85-9; Ethanol CAS No. 64-17-5; N,N-dimethylformamide CAS No. 68-12-2; Dichloromethane CAS No. 75-09-2; Trichloromethane CAS No. 67-66-3; all chemical reagents are commercially available.

[0030] Example 1

[0031] A method for preparing a nylon industrial yarn for airbag, comprising the following steps:

[0032] S1, preparing nylon 66 salt into a 50% salt aqueous solution, adding benzotriazole-phosphate derivative and sodium hypophosphite, under nitrogen protection, heating to 240℃, pressurizing to 2.5 MPa, reacting for 2h, removing most of the water to obtain a prepolymer; wherein the weight ratio of nylon 66 salt, benzotriazole-phosphate derivative and sodium hypophosphite is 100:10:0.1;

[0033] S2, heating the prepolymer obtained in step S1 to 280℃, reducing the pressure to 0.5 MPa, reacting for 4h, reducing the pressure to normal, and after the melt is cast, granulated, and dried, a modified nylon 66 chip is obtained;

[0034] S3, adding the modified nylon 66 chip into a spinning screw extruder, setting the temperature and pressure, extruding from the spinneret hole on the spinneret plate by melt spinning, cooling by side blowing, oiling, stretching, and winding to obtain a nylon industrial yarn;

[0035] Wherein the temperature of the spinning screw extruder is respectively: zone 1 270℃, zone 2 280℃, zone 3 290℃, zone 4 300℃, zone 5 300℃; the pressure of the spinning screw extruder is 10 MPa; the blowing rate is 5 m / min, and the cooling temperature is 20℃; the pre-stretching temperature is 90℃, the stretching temperature is 120℃, and the stretching multiple is 5; the winding speed is 1500 m / min.

[0036] The preparation method of benzotriazole-phosphate derivative is: adding 37.5 g of compound 3 and 4.0 g of sodium hydroxide into 500 mL of 60% ethanol aqueous solution, and passing in ammonia gas, the reaction pressure is 0.6 MPa when the ammonia gas is added, and the reaction is carried out for 4h; after the reaction is completed, ethanol is removed by rotary evaporation, filtered, the filter residue is washed with water, and dried to obtain 30.5 g of benzotriazole-phosphate derivative; the molar ratio of compound 3 and sodium hydroxide is 1:1; the reaction process is:

[0037]

[0038] Benzotriazole-phosphate derivative: ESI (m / z): 357.2 M+H] + , 1 H-NMR (600MHz, DMSO-d6, δppm): 7.98-8.02 (m, 2H), 7.59-7.61 (m, 1H), 7.35-7.37 (m, 1H), 5.30 (s, 2H), 4.46 (t, J = 6.0 Hz, 2H), 3.78 (s, 6H), 3.35-3.40 (m, 5H), 2.84-2.86 (m, 2H), 1.95-1.98 (m, 2H), 1.45-1.47 (m, 2H).

[0039] The preparation method of compound 3 is as follows:

[0040] (1) 25.0 g of benzotriazole, 27.3 g of 1-chlorobutanol, and 21.0 g of sodium hydroxide were added to a 1000 mL solution of N,N-dimethylformamide, and the temperature was raised to 100-110°C, and the reaction was carried out for 2-4 h. After the reaction was completed, it was naturally cooled to room temperature, 1000 mL of water and 2000 mL of dichloromethane were added for extraction, the water phase was extracted once, the organic phases were combined, dried, and concentrated under reduced pressure to obtain 35.8 g of compound 1. The molar ratio of benzotriazole, 1-chlorobutanol, and sodium hydroxide was 1:1.2:2.5; the reaction process is as follows:

[0041]

[0042] Compound 1: ESI (m / z): 192.1 [M+H] + , 1 H-NMR (600MHz, DMSO-d6, δppm): 8.02-8.06 (m, 2H), 7.60-7.63 (m, 1H), 7.35-7.37 (m, 1H), 4.46 (t, J = 6.0 Hz, 2H), 4.14 (s, 1H), 3.46 (t, J = 6.2 Hz, 2H), 1.95-1.97 (m, 2H), 1.52-1.55 (m, 2H).

[0043] (2) 30.0 g of compound 1, 5.3 g of boron trifluoride were added to 800 mL of chloroform solution, 17.4 g of epichlorohydrin was added dropwise under stirring, after dropping, the temperature was raised to 60°C, and the reaction was carried out for 6 h. After the reaction was completed, it was naturally lowered to room temperature, most of the chloroform was removed by rotary evaporation, and 600 mL of water and 600 mL of dichloromethane were added for extraction. The organic phase was collected, dried, and concentrated under reduced pressure to obtain 38.5 g of compound 2. The molar ratio of compound 1, epichlorohydrin, and catalyst was 1:1.2:0.5. The reaction process was as follows:

[0044]

[0045] Compound 2: ESI (m / z): 284.1 [M+H] + , 1 H-NMR (600MHz, DMSO-d6, δppm): 8.0-8.04 (m, 2H), 7.59-7.61 (m, 1H), 7.35-7.37 (m, 1H), 5.37 (s, 1H), 4.48 (t, J=6.0 Hz, 2H), 4.41-4.43 (m, 2H), 3.35-3.37 (m, 4H), 1.94-1.96 (m, 2H), 1.50-1.52 (m, 2H).

[0046] (3) 35.0 g of compound 2 was added to 600 mL of chloroform solution, 15.0 g of dimethyl phosphite was added dropwise, after dropping, the temperature was raised to 60°C, and the reaction was carried out for 4 h. After the reaction was completed, it was naturally lowered to room temperature, the solvent was removed, 600 mL of water and 600 mL of dichloromethane were added for extraction, the organic phase was collected, dried, and concentrated under reduced pressure to obtain 41.6 g of compound 3. The molar ratio of compound 2, dimethyl phosphite, and catalyst was 1:1.1. The reaction process was as follows:

[0047]

[0048] Compound 3: ESI (m / z): 376.1 [M+H] + , 1 H-NMR (600MHz, DMSO-d6, δppm): 7.98-8.03 (m, 2H), 7.58-7.61 (m, 1H), 7.39-7.40 (m, 1H), 4.46 (t, J=6.0 Hz, 2H), 3.80 (s, 6H), 3.56-3.58 (m, 2H), 3.36-3.40 (m, 5H), 1.96-1.98 (m, 2H), 1.44-1.46 (m, 2H).

[0049] Example 2

[0050] A preparation method of nylon industrial yarn for airbag comprises the following steps:

[0051] S1, nylon 66 salt is prepared into a 40% salt aqueous solution, benzotriazole-phosphate derivative and sodium hypophosphite are added, nitrogen protection is carried out, temperature is raised to 230 DEG C, pressure is raised to 2.0 MPa, reaction is carried out for 3 h, most of water is removed, and a prepolymer is obtained; wherein the weight ratio of the nylon 66 salt, the benzotriazole-phosphate derivative and the sodium hypophosphite is 100:5:0.05;

[0052] S2, the prepolymer obtained in step S1 is raised to 270 DEG C, pressure is reduced to 0.3 MPa, reaction is carried out for 3 h, pressure is reduced to normal, the melt is cast, granulated and dried, and modified nylon 66 chips are obtained;

[0053] S3, the modified nylon 66 chips are added to a spinning screw extruder, temperature and pressure are set, melt spinning is carried out from the spinneret holes on the spinneret plate, side blowing cooling is used, oiling, stretching and winding are carried out, and nylon industrial yarn is obtained;

[0054] Wherein the temperature of the spinning screw extruder is respectively 260 DEG C in the first zone, 270 DEG C in the second zone, 280 DEG C in the third zone, 290 DEG C in the fourth zone and 300 DEG C in the fifth zone; the pressure of the spinning screw extruder is 8 MPa; the blowing rate is 4 m / min, the cooling temperature is 20 DEG C; the pre-stretching temperature is 80 DEG C, the stretching temperature is 110 DEG C, and the stretching multiple is 4; the winding speed is 1000 m / min.

[0055] The preparation method of the benzotriazole-phosphate derivative is the same as that in embodiment 1.

[0056] Embodiment 3

[0057] A preparation method of nylon industrial yarn for airbag comprises the following steps:

[0058] S1, nylon 66 salt is prepared into a 40% salt aqueous solution, benzotriazole-phosphate derivative and sodium hypophosphite are added, nitrogen protection is carried out, temperature is raised to 230 DEG C, pressure is raised to 2.0 MPa, reaction is carried out for 3 h, most of water is removed, and a prepolymer is obtained; wherein the weight ratio of the nylon 66 salt, the benzotriazole-phosphate derivative and the sodium hypophosphite is 100:5:0.05;

[0059] S2, the prepolymer obtained in step S1 is raised to 270 DEG C, pressure is reduced to 0.3 MPa, reaction is carried out for 3 h, pressure is reduced to normal, the melt is cast, granulated and dried, and modified nylon 66 chips are obtained;

[0060] S3, the modified nylon 66 chips are added to a spinning screw extruder, temperature and pressure are set, melt spinning is carried out from the spinneret holes on the spinneret plate, side blowing cooling is used, oiling, stretching and winding are carried out, and nylon industrial yarn is obtained;

[0061] The temperature of the spinning screw extruder is 270℃ for zone 1, 270℃ for zone 2, 290℃ for zone 3, 300℃ for zone 4, and 290℃ for zone 5, respectively; the pressure of the spinning screw extruder is 9MPa; the blowing speed is 5m / min, and the cooling temperature is 15℃; the pre-drawing temperature is 90℃, the drawing temperature is 110℃, and the drawing multiple is 5; and the winding speed is 1500m / min.

[0062] The preparation method of the benzotriazole-phosphate derivative is the same as that in Embodiment 1.

[0063] Embodiment 4

[0064] A method for preparing a nylon industrial yarn for an airbag, comprising the following steps:

[0065] S1, preparing a 50% salt aqueous solution of nylon 66 salt, adding a benzotriazole-phosphate derivative and sodium hypophosphite, under nitrogen protection, heating to 230℃, pressurizing to 2.5MPa, and reacting for 2.5h to remove most of the water to obtain a prepolymer; wherein the weight ratio of the nylon 66 salt, the benzotriazole-phosphate derivative, and the sodium hypophosphite is 100:5:0.1;

[0066] S2, heating the prepolymer obtained in step S1 to 270℃, reducing the pressure to 0.5MPa, and reacting for 3h, then reducing the pressure to normal, and after the melt is cast, granulated, and dried, a modified nylon 66 chip is obtained;

[0067] S3, adding the modified nylon 66 chip to a spinning screw extruder, setting the temperature and pressure, extruding from the spinneret holes of the spinneret plate through melt spinning, cooling by side blowing, oiling, drawing, and winding to obtain a nylon industrial yarn;

[0068] The temperature of the spinning screw extruder is 260℃ for zone 1, 280℃ for zone 2, 280℃ for zone 3, 290℃ for zone 4, and 290℃ for zone 5, respectively; the pressure of the spinning screw extruder is 8MPa; the blowing speed is 4m / min, and the cooling temperature is 15℃; the pre-drawing temperature is 80℃, the drawing temperature is 120℃, and the drawing multiple is 4; and the winding speed is 1000m / min.

[0069] The preparation method of the benzotriazole-phosphate derivative is the same as that in Embodiment 1.

[0070] Comparative Example 1

[0071] Compared with Embodiment 1, the raw materials for preparing the nylon industrial yarn are different.

[0072] A method for preparing a nylon industrial yarn for an airbag, comprising the following steps:

[0073] S1, the nylon 66 salt is prepared into a 50% salt aqueous solution, compound 3, sodium hypophosphite are added, under nitrogen protection, the temperature is raised to 240 DEG C, the pressure is raised to 2.5 MPa, reaction 2h, most of the water is removed, and a prepolymer is obtained; wherein the weight ratio of the nylon 66 salt, compound 3, sodium hypophosphite is 100:10:0.1;

[0074] S2 and S3 steps, the preparation method of compound 3 is the same as that of example 1.

[0075] Comparative example 2

[0076] Compared with example 1, the raw materials for preparing the nylon industrial yarn are different.

[0077] A method for preparing a nylon industrial yarn for airbag, comprising the following steps:

[0078] S1, the nylon 66 salt is prepared into a 50% salt aqueous solution, compound 3, sodium hypophosphite are added, under nitrogen protection, the temperature is raised to 240 DEG C, the pressure is raised to 2.5 MPa, reaction 2h, most of the water is removed, and a prepolymer is obtained; wherein the weight ratio of the nylon 66 salt, compound 3, sodium hypophosphite is 100:10:0.1;

[0079] S2 and S3 steps are the same as those of example 1; the dimethyl methylphosphonate is purchased from Jinan Mingxin Chemical Co., Ltd.

[0080] Comparative example 3

[0081] Compared with example 1, the raw materials for preparing the nylon industrial yarn are different.

[0082] A method for preparing a nylon industrial yarn for airbag, comprising the following steps:

[0083] S1, the nylon 66 salt is prepared into a 50% salt aqueous solution, compound 3, sodium hypophosphite are added, under nitrogen protection, the temperature is raised to 240 DEG C, the pressure is raised to 2.5 MPa, reaction 2h, most of the water is removed, and a prepolymer is obtained; wherein the weight ratio of the nylon 66 salt, compound 3, sodium hypophosphite is 100:10:0.1;

[0084] S2 and S3 steps are the same as those of example 1.

[0085] Related tests

[0086] 1. Mechanical and aging resistance test of nylon industrial yarn

[0087] The nylon industrial yarns prepared in Examples 1-4 and Comparative Examples 1-3 were tested for total fineness, breaking strength, and elongation at break. The breaking strength and elongation at break were tested according to GB / T 3916-2013. The aging resistance was tested according to GB / T 16991-2008. The test results are shown in Table 1.

[0088] Table 1: Test results of mechanical properties and aging resistance of nylon industrial yarns

[0089]

[0090]

[0091] As shown in Table 1, the nylon industrial yarns prepared in Examples 1-4 have a fineness of 928-935 dtex, and the breaking strength and elongation at break before and after aging are higher than those of Comparative Examples 1-3. Compared with Comparative Example 1 (raw material: nylon 66 salt + compound 3), Comparative Example 2 (raw material: nylon 66 salt + dimethyl methylphosphonate), and Comparative Example 3 (raw material: nylon 66 salt), the raw material used in Example 1 is nylon 66 salt and a benzotriazole-phosphonate derivative. The benzotriazole-phosphonate derivative contains a rigid benzotriazole group and an amino group in its structure. The rigid benzotriazole group can increase the breaking strength of the nylon industrial yarn and has certain light stability, which can eliminate or slow down photochemical reactions and prevent or delay the photoaging process of the nylon industrial yarn, thereby enhancing the aging resistance of the nylon industrial yarn and making the breaking strength of the nylon industrial yarn before and after aging unchanged. The amino group can participate in the polycondensation of the nylon 66 salt, allowing the benzotriazole-phosphonate derivative to be chemically bonded to the polymer formed by the nylon 66 salt, increasing the bonding force between the benzotriazole-phosphonate derivative and the polymer formed by the nylon 66 salt, and thus improving the comprehensive performance of the final product, the nylon industrial yarn.

[0092] 2. Flame retardant performance test of nylon industrial yarn

[0093] The nylon industrial yarns prepared in Examples 1-4 and Comparative Examples 1-3 were tested for flame retardant performance. The limiting oxygen index was tested according to GB / T 2406-2009. The combustion grade was tested by a vertical burning tester. The test results are shown in Table 2.

[0094] Table 2: Test results of flame retardant performance of nylon industrial yarns

[0095]

[0096]

[0097] From the results of Table 2, it can be seen that the UL-94 ratings of the nylon industrial yarns prepared from Examples 1-4 are all V-0, and the limiting oxygen indexes are all higher than those of Comparative Examples 1-3, indicating that the method for preparing the nylon industrial yarn for airbag provided by the application can successfully prepare the nylon industrial yarn with excellent flame-retardant performance; compared with Comparative Example 1 (raw material is nylon 66 salt + compound 3), Comparative Example 2 (raw material is nylon 66 salt + dimethyl methylphosphonate) and Comparative Example 3 (raw material is nylon 66 salt), the raw material used in Example 1 is nylon 66 salt and benzotriazole-phosphonate derivative, and the benzotriazole-phosphonate derivative containing phosphonate group and triazole group in the benzotriazole-phosphonate derivative can generate P-O, P=O and nitride when burning, and then react with the free radicals generated by the decomposition of the nylon industrial yarn and produce a gas barrier layer, thereby inhibiting the formation and spread of flame, and also forming a carbon layer on the surface of the nylon industrial yarn to prevent the nylon industrial yarn from contacting with oxygen, thus producing a flame-retardant effect, thereby greatly improving the flame-retardant performance of the nylon industrial yarn.

[0098] It should be noted that in this document, such as the term "comprising", "including" or any other variant thereof, is intended to cover non-exclusive inclusion, so that a process, method, article or apparatus including a series of elements includes not only those elements, but also other elements not explicitly listed, or inherent to such a process, method, article or apparatus; although the embodiments of the application have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations of the embodiments can be made without departing from the principles and spirits of the application, and the scope of the application is defined by the appended claims and their equivalents.

Claims

1. A method for preparing nylon industrial yarn for airbags, characterized in that, Includes the following steps: S1. Prepare a 40-50% salt solution of nylon 66 salt, add benzotriazole-phosphate derivative and sodium hypophosphite, and under nitrogen protection, heat to 230-240℃ and pressurize to 2.0-2.5MPa, react for 2-3 hours to remove most of the water and obtain the prepolymer. S2. The prepolymer obtained in step S1 is heated to 270-280℃, reduced to 0.3-0.5MPa, reacted for 2-4 hours, reduced to normal pressure, and the melt is cast, granulated, and dried to obtain modified nylon 66 chips. S3. Add modified nylon 66 chips to a spinning screw extruder, set the temperature and pressure, and extrude them from the spinneret holes through melt spinning. Use side blowing air for cooling, oiling, stretching, and winding to obtain nylon industrial yarn. The chemical structural formula of the benzotriazole-phosphate derivative is as follows: The preparation method of the benzotriazole-phosphate derivative is as follows: Compound 3 and sodium hydroxide are added to a 50-60% aqueous ethanol solution, ammonia gas is introduced, the reaction pressure is 0.4-0.6 MPa when ammonia gas is added, and the reaction is carried out for 3-5 hours to obtain the benzotriazole-phosphate derivative; the chemical structural formula of compound 3 is: The preparation method of compound 3 is as follows: (1) Benzotriazole, 1-chlorobutanol, and sodium hydroxide were added to an N,N-dimethylformamide solution, and the mixture was heated to 100-110℃ and reacted for 2-4 hours to obtain compound 1, with the following chemical structural formula: (2) Compound 1 and the catalyst were added to a chloroform solution, and epichlorohydrin was added dropwise while stirring. After the addition was complete, the temperature was raised to 50-60℃, and the reaction was allowed to proceed for 4-6 hours to obtain compound 2, whose chemical structural formula is: (3) Add compound 2 to a chloroform solution, add dimethyl phosphite dropwise, and after the addition is complete, heat to 50-60℃ and react for 3-4 hours to obtain compound 3.

2. The method for preparing nylon industrial yarn for airbags according to claim 1, characterized in that, The molar ratio of benzotriazole, 1-chlorobutanol, and sodium hydroxide in step (1) is 1:1.1-1.2:2-2.5; the molar ratio of compound 1, epichlorohydrin, and catalyst in step (2) is 1:1.1-1.2:0.2-0.5; and the molar ratio of compound 2 and dimethyl phosphite in step (3) is 1:1.1-1.

2.

3. The method for preparing nylon industrial yarn for airbags according to claim 1, characterized in that, The catalyst mentioned in step (2) is one or a mixture of several of boron trifluoride, ferric chloride, aluminum chloride, and zinc chloride.

4. The method for preparing nylon industrial yarn for airbags according to claim 1, characterized in that, The molar ratio of compound 3 to sodium hydroxide is 1:0.8-1.

5. The method for preparing nylon industrial yarn for airbags according to claim 1, characterized in that, The weight ratio of nylon 66 salt, benzotriazole-phosphate derivative, and sodium hypophosphite in step S1 is 100:5-10:0.05-0.

1.

6. The method for preparing nylon industrial yarn for airbags according to claim 1, characterized in that, In step S3, the temperatures of the spinning screw extruder are as follows: Zone 1 260-270℃, Zone 2 270-280℃, Zone 3 280-290℃, Zone 4 290-300℃, and Zone 5 290-300℃; the pressure of the spinning screw extruder is 8-10MPa.

7. The method for preparing nylon industrial yarn for airbags according to claim 1, characterized in that, In step S3, the blowing rate is 4-5 m / min, the cooling temperature is 15-20℃, the pre-stretching temperature is 80-90℃, the stretching temperature is 110-120℃, the stretching ratio is 4-5, and the winding speed is 1000-1500 m / min.

8. A type of nylon industrial yarn for airbags, characterized in that, It is prepared by the method for preparing nylon industrial yarn according to any one of claims 1-7.

9. The use of the nylon industrial yarn for airbags according to claim 8, characterized in that, Used in the manufacture of automotive airbags.

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