Preparation method of halogen-free flame-retardant coating for polyester fabric

Abstract

The invention relates to a preparation method of a halogen-free flame-retardant coating, in particular to a preparation method of a halogen-free flame-retardant polyacrylate coating for polyester fabrics, which comprises the following steps: (1) preparing a polyacrylate emulsion; (2) preparing a flame retardant dispersion liquid; (3) preparation of a flame-retardant coating: mixing the flame retardant dispersion liquid and a polyacrylate emulsion according to a weight ratio of (0.8-1.3): 1, stirring and mixing uniformly, and then adding a phosphorus-containing polyaziridine cross-linking agent, the weight ratio of the phosphorus-containing polyaziridine cross-linking agent to the polyacrylate emulsion being (0.01-0.05): 1; adjusting the pH value of the coating to 8-9 by using ammonia water with the concentration of 25%; the weight ratio of the hydroxypropyl methyl cellulose to the polyacrylate emulsion is (0.005-0.02): 1, and uniformly mixing the hydroxypropyl methyl cellulose and the polyacrylate emulsion to obtain the polyacrylate flame-retardant coating. The polyacrylate emulsion prepared by the invention has good monomer composition, and can ensure that the flame-retardant polyacrylate coating has good adhesion performance.

Description

Technical Field

[0001] The present invention relates to a preparation method of a halogen-free flame retardant coating, and particularly to a preparation method of a halogen-free flame retardant polyacrylate coating for polyester fabrics. Background Art

[0002] Polyester, whose full name is polyethylene terephthalate fiber, is a synthetic fiber. It is one of the synthetic fibers with the largest production volume and the widest application in the world, and has many excellent properties, such as high strength, good elasticity, wear resistance, wrinkle resistance, easy to clean and quick drying, etc. Polyester is widely used in making various clothes, including but not limited to shirts, trousers, sportswear, outdoor clothing, underwear, etc. Due to its good shape retention and dimensional stability, it is also often used to manufacture permanently pressed suits and skirts. Because of its durability, easy cleaning and wrinkle resistance, polyester is an ideal choice for home decorations such as bedding, curtains, sofa covers, etc. In terms of industrial textiles, polyester fibers are widely used in the production of filter materials, ropes, conveyor belts, automotive interiors, geotextiles, advertising fabrics, etc. Polyester is not only widely used in many fields due to its versatility and cost-effectiveness, but also the application scope of polyester is constantly expanding with the progress of technology.

[0003] However, as a combustible polymer material, the flame retardant ability of polyester fabrics is low. After being ignited, the generated molten droplets can also expand the scope of the fire. Therefore, it is necessary to carry out flame retardant treatment on polyester fabrics. The current methods for flame retarding polyester fabrics mainly include the following three: One is the flame retardant monomer method. In this method, a monomer with flame retardant function is directly prepared, and when polyethylene terephthalate is prepared by polymerization, the flame retardant monomer is polymerized onto the molecular chain of polyethylene terephthalate, so that the prepared polyethylene terephthalate directly has flame retardancy. This method has a high cost, but the obtained polyethylene terephthalate has good flame retardant performance. Another method is the internal addition method. In this method, the flame retardant is evenly distributed inside the fiber to provide a lasting flame retardant effect. Since the flame retardant is added into the polyester fiber, it is not easily eliminated by physical actions such as washing. However, this method may affect the dyeing and mechanical properties of the fiber during the implementation process, and has a high cost and a complex production process. The last method is the post-treatment method. This method has a low cost, is easy to operate, and has little influence on the original characteristics of the fabric. The flame retardant can be attached to the fabric surface by means of coating, spraying or impregnation, etc., and it is a method that is easy to be industrially applied. However, the durability of the flame retardant effect of this method is poor, and it is a challenge to still maintain good flame retardant efficiency especially after multiple washings.

[0004] When implementing the post-treatment method, usually a flame retardant is mixed with an aqueous emulsion paint, etc., to make a flame retardant paint, and then the polyester fabric is coated to make a flame retardant polyester product. When selecting an aqueous emulsion paint, polyurethane paint can be used. This kind of paint has a strong bonding force with polyester fabric, but the price is relatively high. Polyacrylate paint can also be used. The preparation process of this polymer product is mature and has been reported in patents such as 2024117133007.6. At the same time, the price of this kind of paint is relatively low. However, the bonding force between polyacrylate paint and polyester fabric is lower than that of polyurethane paint. As for the flame retardant, halogen-containing flame retardants and nitrogen- and phosphorus-containing flame retardants such as ammonium polyphosphate can be used. The use of halogen flame retardants is restricted in countries such as Europe and the United States because harmful gases such as hydrogen halide are generated during thermal decomposition. The flame retardant effect of ammonium polyphosphate is poor, and at the same time, its water absorption is relatively strong, so its flame retardant performance is poor when used in aqueous flame retardant paints. Aluminum diethylphosphinate is an efficient halogen-free flame retardant, but its polarity is weak, it cannot be dissolved and dispersed in water, and it cannot be directly added to aqueous paints as a flame retardant. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a preparation method of a halogen-free flame retardant paint for polyester fabric, aiming to solve problems such as poor durability of the flame retardant coating and poor flame retardant effect when a halogen-free flame retardant is used alone in flame retardant polyester.

[0006] To achieve the above purpose, a preparation method of a halogen-free flame retardant paint for polyester fabric comprises the following steps:

[0007] (1) Preparation of polyacrylate emulsion

[0008] An emulsifier, mixed monomers and water are emulsified using a homogenizer to prepare a reactant emulsion; under nitrogen protection, a part of the reactant emulsion is added to a reaction kettle, and then an initiator aqueous solution is added dropwise for the first time under stirring, the reaction kettle is heated to 50 - 70 °C and reacted for 1 - 2 hours, then the remaining reactant emulsion is added to the reaction kettle, the initiator aqueous solution is added dropwise for the second time, the temperature of the reaction kettle is raised to 80 °C, after reacting for 2 - 4 hours, the temperature of the reaction kettle is further raised to 85 °C and reacted for 0.5 hour; then the reaction kettle is cooled to room temperature, and the obtained product is filtered to finally obtain a polyacrylate emulsion;

[0009] (2) Preparation of flame retardant dispersion

[0010] An antifoaming agent and water are mixed, and then a surfactant is added to form a uniform surfactant aqueous solution; the flame retardant is added to the surfactant aqueous solution; ultrasonic dispersion treatment is used to uniformly disperse the flame retardant in the surfactant aqueous solution to prepare a flame retardant dispersion;

[0011] (3) Preparation of Flame Retardant Coating

[0012] Mix the flame retardant dispersion and the polyacrylate emulsion in a weight ratio of (0.8 - 1.3):1. After stirring and mixing evenly, add a phosphorus-containing polyaziridine crosslinking agent, where the weight ratio of the phosphorus-containing polyaziridine crosslinking agent to the polyacrylate emulsion is (0.01 - 0.05):1; adjust the pH value of the coating to 8 - 9 using 25% ammonia water; then add a 1.5% aqueous solution of hydroxypropyl methylcellulose, and the weight ratio of hydroxypropyl methylcellulose to the polyacrylate emulsion is (0.005 - 0.02):1, and mix evenly to obtain the polyacrylate flame retardant coating.

[0013] In the step (1), the weight ratio of the emulsifier, monomer, and water is (3 - 7):100:100;

[0014] The reactant emulsion added to the reaction kettle for the first time is 15 - 30% of the total weight. In the initiator aqueous solution added dropwise for the first time, the weight ratio of the initiator to water is 1:(4 - 9), and the weight of the initiator is 0.6 - 2% of the weight of the reactant emulsion added to the reaction kettle at this time;

[0015] In the initiator aqueous solution added dropwise for the second time, the weight ratio of the initiator to water is 1:(4 - 9), and the weight of the initiator is 0.6 - 2% of the weight of the reactant emulsion added to the reaction kettle again at this time.

[0016] The emulsifier is a mixture of sodium dodecyl sulfate and OP - 10, and the weight ratio of the two is 1:4; the initiator used is a mixture of ammonium persulfate and sodium bisulfite, and the weight ratio of the two is 3:1.

[0017] The mixed monomers in the step (1) include four categories A, B, C, and D, and the weight ratio of the four categories is 100:(9 - 11):(3 - 5):(4 - 5); category A monomers include ethyl acrylate, butyl acrylate, and isooctyl acrylate, where the weight ratio of ethyl acrylate, butyl acrylate, and isooctyl acrylate is 1:(2 - 0.5):(0.5 - 0); category B monomer is methyl methacrylate; category C monomers include one or more mixtures of acrylic acid, methacrylic acid, maleic acid, and fumaric acid; category D monomers include one or more mixtures of N - hydroxymethylacrylamide, hydroxyethyl acrylate, and hydroxyethyl methacrylate.

[0018] The weight ratio of the defoamer, surfactant, flame retardant, and water is (0.003 - 0.008):(0.02 - 0.08):(1.2 - 1.7):1; the surfactant is fatty alcohol polyoxyethylene ether, and its molecular structural formula is C n H 2n+1 (OCH2CH2) mOH, where n is an integer greater than 5 and less than 14. It is required that the number-average molecular weight of the fatty alcohol polyoxyethylene ether is greater than 366 and less than 684, and the ratio of its weight-average molecular weight to the number-average molecular weight is less than 2.

[0019] The flame retardant is a compound flame retardant, including three components: aluminum diethylphosphinate, melamine cyanurate and other halogen-free flame retardants. The weight ratio of aluminum diethylphosphinate, melamine cyanurate and other halogen-free flame retardants is 100:(1-5):(5-12); the other halogen-free flame retardants are a mixture of one or more of phytic acid-containing flame retardants, ammonium polyphosphate, piperazine pyrophosphate, melamine polyphosphate, and aluminum hypophosphite.

[0020] The preparation method of the phytic acid-containing flame retardant is as follows: Phytic acid, melamine and water are mixed in a weight ratio of 1:0.76:10, stirred and reacted at 80 °C for 24 hours, and the pH value of the above reaction solution is adjusted to 7 with piperazine, and then obtained by spray drying.

[0021] The preparation method of the phosphorus-containing polyaziridine crosslinking agent is as follows: 1-(2-hydroxyethyl)aziridine and trimethyl phosphate are poured into a container and mixed in a molar ratio of 3:1, and a triethylamine catalyst is added. The temperature is raised to 60-80 °C and reacted for 10-20 hours, and then the temperature is raised to 90-100 °C to distill off triethylamine and low-boiling substances under reduced pressure, and cooled to room temperature to obtain a phosphorus-containing triaziridine crosslinking agent for use; then 1-(2-hydroxyethyl)aziridine and dimethyl methylphosphonate are poured into a container and mixed, and a triethylamine catalyst is added. The temperature is raised to 60-80 °C and reacted for 10-20 hours, and then the temperature is raised to 90-100 °C to distill off triethylamine and low-boiling substances under reduced pressure, and cooled to room temperature to obtain a phosphorus-containing diaziridine crosslinking agent for use; the phosphorus-containing triaziridine crosslinking agent and the phosphorus-containing diaziridine crosslinking agent are mixed in a weight ratio of 100:(50-150) to obtain a phosphorus-containing polyaziridine crosslinking agent.

[0022] The weight of the added triethylamine catalyst is 3-5% of the total weight of 1-(2-hydroxyethyl)aziridine and trimethyl phosphate; 1-(2-hydroxyethyl)aziridine and dimethyl methylphosphonate are in a molar ratio of 2:1, and the added triethylamine catalyst is 3-5% of the total weight of 1-(2-hydroxyethyl)aziridine and dimethyl methylphosphonate.

[0023] The defoamer is an organosilicon defoamer, a polyether defoamer or a polyether-modified silicone defoamer.

[0024] Advantages and effects of the present invention: The polyacrylate emulsion prepared by the present invention has a good monomer composition, which can ensure that the flame-retardant polyacrylate coating has good adhesion performance. A phosphorus-containing polyaziridine crosslinking agent is prepared. Among them, the phosphorus-containing triaziridine crosslinking agent has good crosslinking ability and condensed-phase flame-retardant function, and the phosphine-containing diaziridine crosslinking agent has good crosslinking ability and gas-phase flame-retardant function. In this way, the bonding force between the polyacrylate coating and the polyester fabric is improved, and the flame-retardant performance of the polyacrylate coating is also improved. The surfactant used solves the problem that aluminum diethylphosphinate cannot be dispersed or is unstable in the waterborne polyacrylate coating, so that the developed compound flame retardant can be evenly and stably dispersed into the flame-retardant polyacrylate coating, promoting the exertion of the flame-retardant ability of the compound flame retardant. Piperazine is used in the preparation of the phytic acid-based flame retardant, which effectively promotes the crosslinking of phytic acid and reduces the water solubility of phytate. A compound flame retardant is developed by using the synergistic flame-retardant effect of aluminum diethylphosphinate and other flame retardants, effectively improving the flame-retardant performance of the flame-retardant polyacrylate coating. Specific embodiments

[0025] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present invention.

[0026] In this embodiment, the silicone defoamer is GB-110 defoamer of Jinan Guobang Chemical Co., Ltd., the polyether defoamer is W-806 defoamer of Shandong Jieliefu New Materials Co., Ltd., and the polyether-modified silicone defoamer is B-169 defoamer of Guangdong Zhongke Hongtai New Materials Co., Ltd.; OP-10 is emulsifier OP-10 produced by Jiangsu Haian Petrochemical Factory.

[0027] Example 1

[0028] A preparation method of a halogen-free flame-retardant coating for polyester fabrics, comprising the following steps:

[0029] (1) Preparation of polyacrylate emulsion

[0030] Preparation of mixed monomers: Take 40 grams of ethyl acrylate, 40 grams of butyl acrylate, 20 grams of isooctyl acrylate, 10 grams of methyl methacrylate, 5 grams of methacrylic acid and 5 grams of N-methylolacrylamide and mix them evenly to obtain mixed monomers;

[0031] Aggregation: An emulsifier composed of 1 g of sodium dodecyl sulfate and 4 g of OP-10, 100 g of mixed monomers, and 100 g of water were emulsified using a homogenizer to prepare a reactant emulsion. Under nitrogen protection, 40 g of the reactant emulsion was added to a reaction kettle, and 8 g of an initiator aqueous solution was added dropwise with stirring. The initiator aqueous solution contained 0.6 g of ammonium persulfate, 0.2 g of sodium bisulfite, and 7.2 g of water. The weight of the initiator was 2% of the weight of the reactant emulsion added to the reaction kettle at this time. The reaction kettle was heated to 50 °C and reacted for 2 hours, then the remaining 165 g of the reactant emulsion was added to the reaction kettle, and 16.5 g of the initiator aqueous solution was added dropwise again. The initiator aqueous solution contained 1.2375 g of ammonium persulfate, 0.4125 g of sodium bisulfite, and 14.85 g of water. The weight of the initiator was 1% of the weight of the reactant emulsion added to the reaction kettle again at this time. The temperature of the reaction kettle was raised to 80 °C and reacted for 3 hours. Then the temperature of the reaction kettle was raised to 85 °C and reacted for 0.5 hour. The reaction kettle was cooled to room temperature, and the obtained product was filtered to finally obtain a polyacrylate emulsion;

[0032] (2) Preparation of flame retardant dispersion

[0033] Preparation of phytic acid-containing flame retardant: 100 g of phytic acid, 76 g of melamine, and 1000 g of water were mixed and stirred at 80 °C for 24 hours. The pH value of the above reaction solution was adjusted to 7 using piperazine, and the phytic acid-containing flame retardant was obtained by spray drying;

[0034] Preparation of compound flame retardant: 200 g of aluminum diethylphosphinate, 5 g of melamine cyanurate, and 10 g of phytic acid-containing flame retardant were mixed evenly to prepare a compound flame retardant.

[0035] Preparation of flame retardant dispersion: 0.5 g of GB-110 defoamer was mixed evenly with 100 g of water, and then 5 g of surfactant was added to form a uniform surfactant aqueous solution. The surfactant used was fatty alcohol polyoxyethylene ether, and its molecular structural formula was C8H 17 (OCH2CH2) m OH, its number average molecular weight was 487, and the ratio of its weight average molecular weight to the number average molecular weight was 1.4; 150 g of the compound flame retardant was added to the prepared surfactant aqueous solution and ultrasonic dispersion treatment was used to make the flame retardant evenly dispersed in the surfactant aqueous solution to prepare a flame retardant dispersion;

[0036] (3) Preparation of flame retardant coating

[0037] The preparation method of the phosphorus-containing polyaziridine crosslinking agent is as follows: Pour 261 grams of 1-(2-hydroxyethyl)aziridine and 140 grams of trimethyl phosphate into a container and mix them. Add 12 grams of triethylamine catalyst, heat up to 80 °C, after reacting for 10 hours, heat up to 100 °C and distill off triethylamine and low-boiling substances under reduced pressure. Cool down to room temperature to obtain a phosphorus-containing triaziridine crosslinking agent; Pour 174 grams of 1-(2-hydroxyethyl)aziridine and 124 grams of dimethyl methylphosphonate into a container and mix them. Add 9 grams of triethylamine catalyst, heat up to 80 °C, after reacting for 10 hours, heat up to 100 °C and distill off triethylamine and low-boiling substances under reduced pressure. Cool down to room temperature to obtain a phosphorus-containing diaziridine crosslinking agent; Take 100 grams of the phosphorus-containing triaziridine crosslinking agent and 100 grams of the phosphorus-containing diaziridine crosslinking agent and mix them to obtain a phosphorus-containing polyaziridine crosslinking agent;

[0038] Mixing: Take 100 grams of the flame retardant dispersion and 100 grams of the polyacrylate emulsion and mix them. After stirring and mixing evenly, add 5 grams of the phosphorus-containing polyaziridine crosslinking agent, and use 25% ammonia water to adjust the pH value of the coating to 8. Then add 1 gram of a 1.5% aqueous solution of hydroxypropyl methylcellulose and mix evenly to obtain polyacrylate flame retardant coating 1.

[0039] To illustrate the influence of the prepared polyacrylate flame retardant coating 1 on the flame retardant performance, etc. of polyester fabrics, coat the prepared polyacrylate flame retardant coating on the surface of a polyester fabric with a weight of 120 grams per square meter, dry it at 110 °C for 5 minutes, and then dry it at 160 °C for 3 minutes to prepare flame retardant polyester 1. During the coating process, by controlling the usage amount of polyacrylate flame retardant coating 1, the weight of the dried flame retardant polyester 1 per square meter is increased by 25 grams compared with the original polyester fabric.

[0040] Flame retardant performance test: Test the flame retardant performance of the prepared flame retardant polyester 1 and the flame retardant polyester 1 after washing according to GB / T 5455-2014, GB / T 17591-2006 and GB / T 5454-1997.

[0041] Washing stability test: Put 5 grams of flame retardant polyester into 250 grams of water, wash it in water at 30 °C for 1 hour, take it out and dry it. Repeat the process of washing-drying 5 times, then test the weight of the finally dried flame retardant polyester, record the weight X of the flame retardant polyester after 5 times of washing-drying, and calculate the washing weight loss rate according to the formula (5 - X) / 5 × 100% to determine the washing stability of polyacrylate flame retardant coating 1.

[0042] Adhesion Test: Take a flame-retardant polyester fabric that is 10 cm wide and 20 cm long. Fold the side coated with polyacrylate flame-retardant coating 1 in half, and use a press to press the folded flame-retardant polyester fabric at a pressure of 2 MPa at 30 °C for 0.5 hours. Unfold the folded flame-retardant polyester fabric and observe whether the polyacrylate flame-retardant coating 1 falls off from the polyester fabric substrate to determine the adhesion of the polyacrylate flame-retardant coating 1.

[0043] The test results are shown in Table 1.

[0044] Table 1 Performance Test Results of Flame-Retardant Polyester 1

[0045]

[0046] As can be seen from Table 1, the oxygen index of the prepared flame-retardant polyester 1 exceeds 29%, the afterflame time and the smoldering time are both 0 seconds, and there is no molten drop during combustion, reaching the B1 level in the test standard. Flame-retardant polyester 1 shows good flame-retardant performance. The oxygen index of the polyester fabric without the flame-retardant coating is less than 20%, it burns completely during combustion, and there is a molten drop phenomenon, and it does not obtain a rating, belonging to flammable materials. In order to determine other properties of the flame-retardant polyester 1, other tests were also carried out on it. In the washing test, the weight loss of the flame-retardant polyester 1 is less than 2%, indicating that the polyacrylate flame-retardant coating 1 has good washing resistance and good adhesion to the polyester substrate. The flame-retardant polyester 1 after the washing test shows similar properties to the flame-retardant polyester 1 before washing. Since the polyester fabric will be folded, rolled, etc. during handling and storage, if the adhesion of the polyacrylate flame-retardant coating 1 itself is too large, it will fall off and peel off from the polyester substrate during these processes. From the adhesion test experiment, no falling-off phenomenon was found, indicating that the polyacrylate flame-retardant coating 1 has good adhesion and meets the actual application requirements.

[0047] Comparative Example 1

[0048] The surfactant used in the preparation of the flame retardant dispersion in Example 1 was sodium dodecylbenzenesulfonate. Other conditions were the same as in Example 1. The prepared flame retardant dispersion had the complex flame retardant floating on the surface of the surfactant aqueous solution and could not be completely dispersed into the surfactant aqueous solution;

[0049] And when preparing the flame-retardant coating, the flame retardant dispersion was mixed with the polyacrylate emulsion. After sufficient stirring, the flame retardant still floated on the surface of the mixed solution. Then, following the steps in Example 1, there was still a phenomenon that the flame retardant floated on the surface of the mixed solution after the final mixing and stirring, and a polyacrylate flame-retardant coating with uniformly mixed components could not be obtained.

[0050] Comparative Example 2

[0051] The surfactant in Comparative Example 1 was cetyltrimethylammonium bromide. Other conditions were the same as in Comparative Example 1.

[0052] The resulting polyacrylate flame retardant coating cannot achieve uniform mixing of all components.

[0053] Comparative Example 3

[0054] The surfactant in Comparative Example 1 is coconut fatty acid methyl monoethanolamide, and the others are the same as in Comparative Example 1.

[0055] The resulting polyacrylate flame retardant coating cannot achieve uniform mixing of all components.

[0056] Comparative Example 4

[0057] The surfactant in Comparative Example 1 is nonylphenol polyoxyethylene ether, and the others are the same as in Comparative Example 1.

[0058] The resulting polyacrylate flame retardant coating cannot achieve uniform mixing of all components.

[0059] Comparative Example 5

[0060] The surfactant in Comparative Example 1 is polyethylene glycol 400, and the others are the same as in Comparative Example 1.

[0061] The resulting polyacrylate flame retardant coating cannot achieve uniform mixing of all components.

[0062] Comparative Example 6

[0063] The surfactant in Comparative Example 1 is fatty alcohol polyoxyethylene ether, and its molecular structural formula is C 16 H 33 (OCH2CH2)mOH, its number average molecular weight is 865, and the ratio of its weight average molecular weight to the number average molecular weight is 1.5, and the others are the same as in Comparative Example 1.

[0064] The resulting polyacrylate flame retardant coating cannot achieve uniform mixing of all components.

[0065] Comparative Example 7

[0066] The surfactant in Example 1 is fatty alcohol polyoxyethylene ether, and its molecular structural formula is C4H9(OCH2CH2) m OH, its number average molecular weight is 216, and the ratio of its weight average molecular weight to the number average molecular weight is 1.4, and the others are the same as in Example 1. There is a phenomenon that the compounded flame retardant precipitates in the surfactant aqueous solution and cannot be suspended and dispersed in the surfactant aqueous solution in the prepared flame retardant dispersion;

[0067] And when preparing the flame retardant coating, it is carried out according to Example 1, and the obtained polyacrylate flame retardant coating D7 is obtained.

[0068] Prepare flame retardant polyester D7 according to the coating method in Example 1 and conduct relevant tests. All the test results are shown in Table 2.

[0069] Table 2 Performance test results of flame-retardant polyester D7

[0070]

[0071] From the test results, the flame-retardant performance of flame-retardant polyester D7 is poor and does not meet the requirements of the flame-retardant level for the flame-retardant test. This is because the compound flame retardant cannot be well dispersed into the polyacrylate flame-retardant coating D7, and there is a sedimentation phenomenon during the preparation process. During the coating process of polyester, it is also difficult to achieve uniform coating of the compound flame retardant, resulting in poor flame-retardant performance of flame-retardant polyester D7.

[0072] Comparative example 8

[0073] The preparation steps of the flame retardant dispersion in Example 1 are as follows: Mix 0.5 grams of GB-110 defoamer with 100 grams of water evenly, take 150 grams of the compound flame retardant and add it to the prepared aqueous solution, use ultrasonic dispersion treatment, and then add 5 grams of surfactant. The surfactant used is fatty alcohol polyoxyethylene ether, and its molecular structural formula is C8H 17 (OCH2CH2) m OH, its number-average molecular weight is 487, and the ratio of its weight-average molecular weight to the number-average molecular weight is 1.4. Part of the compound flame retardant precipitates in the aqueous solution, and part of the compound flame retardant floats on the surface of the aqueous solution, and the compound flame retardant cannot be evenly suspended and dispersed in the aqueous solution;

[0074] Preparation steps of the flame-retardant coating:

[0075] Preparation method of the phosphorus-containing polyaziridine cross-linking agent: The same as Example 1

[0076] Mixing: Add 255.5 grams of polyacrylate emulsion to the above-mentioned flame retardant dispersion and mix. After stirring well, add 12.775 grams of the phosphorus-containing polyaziridine cross-linking agent, and adjust the pH value of the coating to 8 with 25% ammonia water. Then add 2.555 grams of a 1.5% aqueous solution of hydroxypropyl methylcellulose. After sufficient stirring, there is still a phenomenon that the flame retardant floats on the surface of the mixed solution, and a polyacrylate flame-retardant coating with evenly mixed components cannot be obtained. This is because the surfactant needs to be dissolved in water first to make the compound flame retardant disperse well in water.

[0077] Comparative example 9

[0078] (1) Preparation of polyacrylate emulsion

[0079] Preparation of mixed monomers: 400 g of ethyl acrylate, 400 g of butyl acrylate, 200 g of isooctyl acrylate, 100 g of methyl methacrylate, 50 g of methacrylic acid and 50 g of N - hydroxymethyl acrylamide were mixed evenly to obtain mixed monomers;

[0080] Polymerization: An emulsifier composed of 10 g of sodium dodecyl sulfate and 40 g of OP - 10, 1000 g of mixed monomers and 1000 g of water were emulsified using a homogenizer to prepare a reactant emulsion; Under nitrogen protection, 400 g of the reactant emulsion was added to a reaction kettle, and 80 g of an initiator aqueous solution was added dropwise with stirring. The initiator aqueous solution contained 6 g of ammonium persulfate, 2 g of sodium bisulfite and 72 g of water. The weight of the initiator was 2% of the weight of the reactant emulsion added to the reaction kettle at this time; The reaction kettle was heated to 50 °C and reacted for 2 hours, then the remaining 1650 g of the reactant emulsion was added to the reaction kettle, and 165 g of the initiator aqueous solution was added dropwise again. The initiator aqueous solution contained 12.375 g of ammonium persulfate, 4.125 g of sodium bisulfite and 148.5 g of water. The weight of the initiator was 1% of the weight of the reactant emulsion added to the reaction kettle again at this time; The temperature of the reaction kettle was raised to 80 °C and reacted for 3 hours. Then the temperature of the reaction kettle was raised to 85 °C and reacted for 0.5 hours. The reaction kettle was cooled to room temperature, and the obtained product was filtered to finally obtain a polyacrylate emulsion;

[0081] (2) Preparation of flame - retardant coating

[0082] Preparation of phytic acid - containing flame retardant: Same as Example 1.

[0083] Preparation of compound flame retardant: Same as Example 1.

[0084] The preparation method of phosphorus - containing polyaziridine cross - linker is: Same as Example 1.

[0085] Preparation of flame - retardant coating: 0.5 g of GB - 110 defoamer was mixed evenly with 100 g of water, and then 5 g of a surfactant was added to form a uniform surfactant aqueous solution. The surfactant used was fatty alcohol polyoxyethylene ether, and its molecular structural formula was C8H 17 (OCH2CH2) mOH, with a number average molecular weight of 487 and a ratio of weight average molecular weight to number average molecular weight of 1.4; 255.5 g of polyacrylate emulsion was added to an aqueous surfactant solution, and then 150 g of a compounded flame retardant was added to the prepared mixed solution of acrylate emulsion and surfactant, followed by ultrasonic dispersion treatment. After thorough mixing, 12.775 g of a phosphorus-containing polyaziridine crosslinking agent was added, and the pH value of the coating was adjusted to 8 using 25% ammonia water. Then, 2.555 g of a 1.5% aqueous solution of hydroxypropyl methylcellulose was added. After thorough mixing, there was still a phenomenon that the flame retardant floated on the surface of the mixed solution, and a polyacrylate flame retardant coating with uniformly mixed components could not be obtained.

[0086] This indicates that by changing the preparation steps of the polyacrylate flame retardant coating and adding the polyacrylate emulsion to water first, there will be a situation where the flame retardant cannot be uniformly dispersed in the polyacrylate flame retardant coating, and the polyacrylate flame retardant coating prepared in this way cannot be used for coating polyester fabrics.

[0087] Comparative Example 10

[0088] Preparation of the mixed monomers in Step 1 of Example 1: 66.6 g of butyl acrylate, 33.4 g of isooctyl acrylate, 10 g of methyl methacrylate, 5 g of methacrylic acid, and 5 g of N-hydroxymethylacrylamide were mixed evenly to obtain the mixed monomers. The rest was the same as in Example 1.

[0089] Finally, a uniformly mixed polyacrylate flame retardant coating D10 was obtained.

[0090] The flame-retardant polyester D10 was prepared according to the coating method in Example 1 and subjected to relevant tests. All the test results are shown in Table 3.

[0091] Table 3 Performance test results of flame-retardant polyester D10

[0092]

[0093] As can be seen from Table 3, the flame retardancy of the prepared flame-retardant polyester D10 is not much different from that of the flame-retardant polyester 1 prepared in Example 1. However, the weight loss after washing exceeds 3%. The flame retardancy of the flame-retardant polyester D10 changes little after the washing test. However, in the viscosity test, the phenomenon of peeling off of the flame-retardant coating occurred. This is because only butyl acrylate and isooctyl acrylate, the A-type monomers in the polyacrylate, are present, and the glass transition temperature of the polymers corresponding to these two monomers is much lower than that of the polymer corresponding to ethyl acrylate monomer. A higher content of such monomers in the polyacrylate will cause the prepared polyacrylate to have too high viscosity at room temperature. When the coating is folded and contacted, there is a strong viscosity between the contacting polyacrylate coatings, resulting in peeling off from the polyester substrate. This is not conducive to the storage and transportation of the flame-retardant polyester.

[0094] Comparative Example 11

[0095] Preparation of the mixed monomers in Step 1 of Example 1: 40 g of ethyl acrylate, 40 g of butyl acrylate, 20 g of isooctyl acrylate, and 10 g of methyl methacrylate were taken and mixed evenly to obtain the mixed monomers. The others were the same as in Example 1.

[0096] Finally, they were mixed evenly to obtain the polyacrylate flame-retardant coating D11.

[0097] The flame-retardant polyester D11 was prepared according to the coating method in Example 1, and relevant tests were carried out. All the test results are shown in Table 4.

[0098] Table 4 Performance test results of the flame-retardant polyester D11

[0099]

[0100] It can be seen from Table 4 that the flame-retardant performance of the prepared flame-retardant polyester D11 is similar to that of the flame-retardant polyester 1 prepared in Example 1. However, the weight loss after washing exceeded 9%. The flame-retardant performance of the flame-retardant polyester D11 after the washing test decreased significantly, and the combustion level dropped to B2 level. This is because the polyacrylate flame-retardant coating D11 does not contain two kinds of monomers with the ability to promote the cross-linking of the polyacrylate flame-retardant coating during the preparation process, resulting in a significant reduction in the adhesion of the polyacrylate flame-retardant coating on the polyester substrate, causing the polyacrylate flame-retardant coating to fall off during the washing process, thereby reducing the flame-retardant performance of the flame-retardant polyester D11 after the washing test.

[0101] Comparative Example 12

[0102] In the polymerization step of preparing the polyacrylate emulsion in Example 1, after filtering the obtained product, the pH value of the emulsion was adjusted to 7 with ammonia water, and finally the polyacrylate emulsion was obtained; the others were the same as in Example 1.

[0103] Finally, they were mixed evenly to obtain the polyacrylate flame-retardant coating D12.

[0104] The flame-retardant polyester D12 was prepared according to the coating method in Example 1, and relevant tests were carried out. All the test results are shown in Table 5.

[0105] Table 5 Performance test results of the flame-retardant polyester D12

[0106]

[0107] As can be seen from Table 5, the flame-retardant polyester D12 has good flame-retardant properties and a combustion rating of B1. However, a certain weight loss occurred during the water washing process. The flame-retardant properties of the flame-retardant polyester D12 after the water washing test decreased significantly, and the combustion rating dropped to B2. This is because when preparing the polyacrylate emulsion, ammonia water was added to the prepared emulsion, reducing the ability of the cross-linked stable compound flame retardant of the polyacrylic acid monomer, resulting in a certain loss of the flame retardant in the flame-retardant polyester D12 during the water washing test.

[0108] Comparative Example 13

[0109] In Example 1, the compound flame retardant was prepared by mixing 200 g of aluminum diethylphosphinate and 5 g of melamine cyanurate uniformly to prepare the compound flame retardant. Others were the same as in Example 1.

[0110] Finally, it was mixed uniformly to obtain the polyacrylate flame-retardant coating D13.

[0111] The flame-retardant polyester D13 was prepared according to the coating method in Example 1 and relevant tests were carried out. All the test results are shown in Table 6.

[0112] Table 6 Performance test results of flame-retardant polyester D13

[0113]

[0114]

[0115] As can be seen from Table 6, although the char length of the flame-retardant polyester D13 did not exceed 15 cm, there was a phenomenon of smoldering, and the smoldering time exceeded 5 s. Therefore, the combustion rating of the flame-retardant polyester D13 is B2. The rating is still B2 after water washing. Its flame-retardant performance is worse than that of the flame-retardant polyester 1 prepared in Example 1. This is because the compound flame retardant does not contain the phosphorus-containing flame retardant phytic acid-containing flame retardant, resulting in continuous burning and smoldering phenomena during combustion, and the continuous burning time exceeds 5 s.

[0116] Comparative Example 14

[0117] In Example 1, the compound flame retardant was prepared by mixing 200 g of aluminum diethylphosphinate and 10 g of phytic acid-containing flame retardant uniformly to prepare the compound flame retardant. Others were the same as in Example 1.

[0118] Finally, it was mixed uniformly to obtain the polyacrylate flame-retardant coating D14.

[0119] The flame-retardant polyester D14 was prepared according to the coating method in Example 1 and relevant tests were carried out. All the test results are shown in Table 7.

[0120] Table 7 Performance test results of flame-retardant polyester D14

[0121]

[0122] As can be seen from Table 7, the char length of flame-retardant polyester D14 exceeds 15 cm, and there is a phenomenon of continued burning. Although the continued burning time does not exceed 5 seconds, the combustion rating of flame-retardant polyester D14 is B2. The rating remains B2 after washing. Its flame-retardant performance is worse than that of the flame-retardant polyester 1 prepared in Example 1. This is because the compound flame retardant does not contain melamine cyanurate, a nitrogen-containing gas-phase flame retardant.

[0123] Comparative Example 15

[0124] In Example 1, the compound flame retardant was prepared by taking 50 g of melamine cyanurate and 100 g of phytic acid-containing flame retardant and mixing them evenly to prepare the compound flame retardant. Others were the same as in Example 1.

[0125] Finally, polyacrylate flame-retardant coating D15 was obtained by mixing evenly.

[0126] Flame-retardant polyester D15 was prepared according to the coating method in Example 1, and relevant tests were carried out. All the test results are shown in Table 8.

[0127] Table 8 Performance test results of flame-retardant polyester D15

[0128]

[0129] As can be seen from Table 8, although the char length of flame-retardant polyester D15 does not exceed 30 cm, there are phenomena of continued burning and smoldering. The combustion rating of flame-retardant polyester D15 is unrated. The rating remains unrated after washing. Its flame-retardant performance is worse than that of the flame-retardant polyesters D13 and D14 prepared in Comparative Examples 13 and 14. This is because the compound flame retardant does not contain aluminum diethylphosphinate, a flame retardant, resulting in intense combustion of flame-retardant polyester D15 during testing.

[0130] Comparative Example 16

[0131] In Example 1, the compound flame retardant was prepared by taking 200 g of aluminum diethylphosphinate as the flame retardant. Others were the same as in Example 1.

[0132] Finally, polyacrylate flame-retardant coating D16 was obtained by mixing evenly.

[0133] Flame-retardant polyester D16 was prepared according to the coating method in Example 1, and relevant tests were carried out. All the test results are shown in Table 9.

[0134] Table 9 Performance test results of flame-retardant polyester D16

[0135]

[0136] As can be seen from Table 9, although the char length of flame-retardant polyester D16 did not exceed 15 cm, there was a phenomenon of smoldering, and the smoldering time exceeded 5 seconds. Therefore, the combustion rating of flame-retardant polyester D16 was B2. The rating remained B2 after washing. Its flame-retardant performance was worse than that of the flame-retardant polyester 1 prepared in Example 1. This was because the compound flame retardant did not contain cyanuric acid cyanurate and phytic acid-containing flame retardant, resulting in afterglow and smoldering phenomena during combustion, and the afterglow time exceeded 5 seconds.

[0137] Comparative Example 17

[0138] In Example 1, the compound flame retardant was prepared by taking 200 g of aluminum diethylphosphinate, 1 g of melamine cyanurate, and 30 g of phytic acid-containing flame retardant, and mixing them evenly to prepare the compound flame retardant. Others were the same as in Example 1.

[0139] Finally, it was mixed evenly to obtain the polyacrylate flame-retardant coating D17.

[0140] The flame-retardant polyester D17 was prepared according to the coating method in Example 1, and relevant tests were carried out. All the test results are shown in Table 10.

[0141] Table 10 Performance test results of flame-retardant polyester D17

[0142]

[0143] As can be seen from Table 10, the char length of flame-retardant polyester D17 exceeded 15 cm, and there was an afterglow phenomenon. The combustion rating of flame-retardant polyester D17 was B2. It should be noted that for flame-retardant polyester products, application enterprises usually require the afterglow time and smoldering time to be 0. The rating remained B2 after washing. Its flame-retardant performance was worse than that of the flame-retardant polyester 1 prepared in Example 1. This was because the component ratios in the compound flame retardant were not within the range.

[0144] Comparative Example 18

[0145] The preparation method of the phosphorus-containing polyaziridine crosslinking agent in Example 1 was as follows: 261 g of 1-(2-hydroxyethyl)aziridine and 140 g of trimethyl phosphate were poured into a container and mixed, that is, the molar ratio was 3:1; then 12 g of triethylamine catalyst was added, and the temperature was raised to 80 °C. After reacting for 10 hours, the temperature was raised to 100 °C and triethylamine and low-boiling substances were removed by vacuum distillation, and the temperature was lowered to room temperature. The phosphorus-containing triaziridine crosslinking agent was obtained and directly used as the phosphorus-containing polyaziridine crosslinking agent. Others were the same as in Example 1.

[0146] Finally, it was mixed evenly to obtain the polyacrylate flame-retardant coating D18.

[0147] The flame-retardant polyester D18 was prepared according to the coating method in Example 1, and relevant tests were carried out. All the test results are shown in Table 11.

[0148] Table 11 Performance Test Results of Flame Retardant Polyester D18

[0149]

[0150] As can be seen from Table 11, the ratings of flame retardant polyester D18 before and after washing are both B1 level. However, there is a phenomenon of continued combustion during combustion of flame retardant polyester D18 before and after washing, and its flame retardant performance is slightly lower than that of flame retardant polyester 1 prepared in Example 1. This is because the phosphorus-containing polyaziridine crosslinking agent does not contain organic phosphorus. Although its crosslinking performance is excellent, its gas-phase flame retardant ability is slightly lower. It should be noted that for flame retardant polyester products, application enterprises usually require that the continued combustion time and smoldering time be 0. Therefore, the performance of flame retardant polyester D18 is worse than that of flame retardant polyester 1.

[0151] Comparative Example 19

[0152] The preparation method of the phosphorus-containing polyaziridine crosslinking agent in Example 1 is as follows: Pour 174 grams of 1-(2-hydroxyethyl)aziridine and 124 grams of dimethyl methylphosphonate into a container and mix them, that is, the molar ratio is 2:1; add 9 grams of triethylamine catalyst, heat up to 80 °C, after reacting for 10 hours, heat up to 100 °C and distill off triethylamine and low-boiling substances under reduced pressure, and cool to room temperature. The phosphorus-containing binary aziridine crosslinking agent is obtained and directly used as the phosphorus-containing polyaziridine crosslinking agent.

[0153] Finally, polyacrylate flame retardant coating D19 is obtained by mixing evenly.

[0154] Flame retardant polyester D19 is prepared according to the coating method in Example 1 and relevant tests are carried out. All the test results are shown in Table 12.

[0155] Table 12 Performance Test Results of Flame Retardant Polyester D19

[0156]

[0157] As can be seen from Table 12, the ratings of flame retardant polyester D19 before washing are all B1 level. However, there is a phenomenon of continued combustion during combustion of flame retardant polyester D19 after washing, and its flame retardant performance is lower than that of flame retardant polyester 1 prepared in Example 1. This is because the phosphorus-containing polyaziridine crosslinking agent only consists of a phosphorus-containing binary aziridine crosslinking agent. Although this crosslinking agent has good gas-phase flame retardant ability, its crosslinking ability is slightly lower, and there will be a certain weight loss of the flame retardant coating during the washing process.

[0158] Comparative Example 20

[0159] In the preparation method of the phosphorus-containing polyaziridine crosslinking agent in Example 1, 100 grams of phosphorus-containing ternary aziridine crosslinking agent and 200 grams of phosphorus-containing binary aziridine crosslinking agent are mixed to obtain the phosphorus-containing polyaziridine crosslinking agent. Others are the same as in Example 1.

[0160] Finally, it is uniformly mixed to obtain the polyacrylate flame retardant coating D20.

[0161] Prepare the flame retardant polyester D20 according to the coating method in Example 1 and conduct relevant tests. All the test results are shown in Table 13.

[0162] Table 13 Performance test results of flame retardant polyester D20

[0163]

[0164]

[0165] As can be seen from Table 13, the ratings of the flame retardant polyester D20 before washing are all B1 level. However, there is afterglow combustion phenomenon during combustion of the flame retardant polyester D20 after washing, and its flame retardant performance is lower than that of the flame retardant polyester 1 prepared in Example 1. This is because in the phosphorus-containing polyaziridine crosslinking agent, the content of the phosphine-containing bisaziridine crosslinking agent is too high. Although this crosslinking agent has good gas-phase flame retardant ability, its crosslinking ability is slightly lower, and there will be a certain weight loss of the flame retardant coating during the washing process.

[0166] Example 2

[0167] (1) Preparation of polyacrylate emulsion

[0168] Preparation of mixed monomers: Take 500 g of ethyl acrylate, 500 g of butyl acrylate, 110 g of methyl methacrylate, 30 g of methacrylic acid and 40 g of N-hydroxymethylacrylamide and mix them evenly to obtain mixed monomers.

[0169] Polymerization: Emulsify the emulsifier composed of 10 g of sodium dodecyl sulfate and 40 g of OP-10, 1000 g of mixed monomers and 1000 g of water using a homogenizer to prepare the reactant emulsion. Under nitrogen protection, add 307.5 g of the reactant emulsion to the reaction kettle, and dropwise add 61.5 g of the initiator aqueous solution while stirring. The initiator aqueous solution contains 4.6125 g of ammonium persulfate, 1.5375 g of sodium bisulfite and 55.35 g of water. The weight of the initiator is 2% of the weight of the reactant emulsion added to the reaction kettle at this time. Heat the reaction kettle to 50 °C and react for 1 hour, then add the remaining 1742.5 g of the reactant emulsion to the reaction kettle, and dropwise add 348.5 g of the initiator aqueous solution again. The initiator aqueous solution contains 26.1375 g of ammonium persulfate, 8.7125 g of sodium bisulfite and 313.65 g of water. The weight of the initiator is 2% of the weight of the reactant emulsion added to the reaction kettle again at this time. Raise the temperature of the reaction kettle to 80 °C and react for 3 hours. Then raise the temperature of the reaction kettle to 85 °C and react for 0.5 hour. Lower the temperature of the reaction kettle to room temperature, filter the obtained product, and finally obtain the polyacrylate emulsion.

[0170] (2) Preparation of Flame Retardant Dispersion

[0171] Preparation of compound flame retardant: Take 200 g of aluminum diethylphosphinate, 10 g of melamine cyanurate, and 10 g of ammonium polyphosphate, mix them evenly to prepare a compound flame retardant.

[0172] Preparation of flame retardant dispersion: Mix 0.3 g of GB-110 defoamer with 100 g of water evenly, and then add 2 g of surfactant to form a uniform surfactant aqueous solution. The surfactant used is fatty alcohol polyoxyethylene ether, and its molecular structural formula is C 13 H 27 (OCH2CH2) m OH, its number average molecular weight is 684, and the ratio of its weight average molecular weight to the number average molecular weight is 1.8. Take 140 g of the compound flame retardant and add it to the prepared surfactant aqueous solution, and use ultrasonic dispersion treatment to make the flame retardant evenly disperse in the surfactant aqueous solution to prepare a flame retardant dispersion.

[0173] (3) Preparation of Flame Retardant Coating

[0174] The preparation method of the phosphorus-containing polyfunctional aziridine crosslinking agent is as follows: Pour 261 g of 1-(2-hydroxyethyl)aziridine and 140 g of trimethyl phosphate (molar ratio 3:1) into a container and mix them. Add 20 g of triethylamine catalyst, heat up to 60 °C, after reacting for 20 hours, heat up to 90 °C and carry out vacuum distillation to remove triethylamine and low-boiling substances, and cool to room temperature to obtain a phosphorus-containing trifunctional aziridine crosslinking agent; Pour 174 g of 1-(2-hydroxyethyl)aziridine and 124 g of dimethyl methylphosphonate (molar ratio 2:1) into a container and mix them. Add 12 g of triethylamine catalyst, heat up to 60 °C, after reacting for 20 hours, heat up to 100 °C and carry out vacuum distillation to remove triethylamine and low-boiling substances, and cool to room temperature. Obtain a phosphorus-containing bifunctional aziridine crosslinking agent. Take 100 g of the phosphorus-containing trifunctional aziridine crosslinking agent and mix it with 150 g of the phosphorus-containing bifunctional aziridine crosslinking agent to obtain a phosphorus-containing polyfunctional aziridine crosslinking agent.

[0175] Mixing: Take 130 g of the flame retardant dispersion and mix it with 100 g of polyacrylate emulsion. After stirring and mixing evenly, add 1 g of the phosphorus-containing polyfunctional aziridine crosslinking agent. Use 25% ammonia water to adjust the pH value of the coating to 9. Then add 0.5 g of a 1.5% aqueous solution of hydroxypropyl methylcellulose. Mix evenly to obtain polyacrylate flame retardant coating 2.

[0176] Prepare flame-retardant polyester 2 according to the coating method in Example 1 and conduct relevant tests. All the test results are shown in Table 14.

[0177] Table 14 Performance Test Results of Flame-Retardant Polyester 2

[0178]

[0179] As can be seen from Table 14, the limiting oxygen index (LOI) of the prepared flame-retardant polyester 2 exceeded 29% before and after water washing. The afterflame time and afterglow time were both 0 s, and no molten drops dripped during combustion, reaching Class B1 in the test standard. Flame-retardant polyester 2 exhibited good flame-retardant properties.

[0180] Example 3

[0181] (1) Preparation of polyacrylate emulsion

[0182] Preparation of mixed monomers: 290 g of ethyl acrylate, 580 g of butyl acrylate, 130 g of isooctyl acrylate, 90 g of methyl methacrylate, 50 g of acrylic acid, and 40 g of 2-hydroxyethyl acrylate were mixed evenly to obtain mixed monomers.

[0183] Polymerization: An emulsifier composed of 10 g of sodium dodecyl sulfate and 40 g of OP-10, 1000 g of mixed monomers, and 1000 g of water were emulsified using a homogenizer to prepare a reactant emulsion. Under nitrogen protection, 615 g of the reactant emulsion was added to the reaction kettle, and 123 g of an initiator aqueous solution was added dropwise with stirring. The initiator aqueous solution contained 9.225 g of ammonium persulfate, 3.075 g of sodium bisulfite, and 110.7 g of water. The weight of the initiator was 2% of the weight of the reactant emulsion added to the reaction kettle at this time. The reaction kettle was heated to 50 °C and reacted for 1 hour, then the remaining 1435 g of the reactant emulsion was added to the reaction kettle, and 143.5 g of an initiator aqueous solution was added dropwise again. The initiator aqueous solution contained 10.7625 g of ammonium persulfate, 3.5875 g of sodium bisulfite, and 129.15 g of water. The weight of the initiator was 1% of the weight of the reactant emulsion added to the reaction kettle again at this time. The temperature of the reaction kettle was raised to 80 °C and reacted for 4 hours. Then the temperature of the reaction kettle was raised to 85 °C and reacted for 0.5 hour. The reaction kettle was cooled to room temperature, and the obtained product was filtered to finally obtain a polyacrylate emulsion.

[0184] (2) Preparation of flame retardant dispersion

[0185] Preparation of compound flame retardant: 200 g of aluminum diethylphosphinate, 2 g of melamine cyanurate, and 24 g of melamine polyphosphate were mixed evenly to prepare a compound flame retardant.

[0186] Preparation of flame retardant dispersion: 0.8 g of B-169 defoamer was mixed evenly with 100 g of water, and then 8 g of surfactant was added to form a uniform surfactant aqueous solution. The surfactant used was fatty alcohol polyoxyethylene ether, and its molecular structural formula was C6H 13 (OCH2CH2) mOH, with a number-average molecular weight of 366 and a ratio of weight-average molecular weight to number-average molecular weight of 1.5. 160 g of the compounded flame retardant was added to the prepared aqueous surfactant solution, and ultrasonic dispersion treatment was used to uniformly disperse the flame retardant into the aqueous surfactant solution to prepare a flame retardant dispersion.

[0187] (3) Preparation of the flame retardant coating

[0188] The preparation method of the phosphorus-containing polyaziridine crosslinking agent is as follows: 261 g of 1-(2-hydroxyethyl)aziridine and 140 g of trimethyl phosphate (molar ratio 3:1) were poured into a container and mixed, 20 g of triethylamine catalyst was added, the temperature was raised to 60 °C, after reacting for 20 hours, the temperature was raised to 90 °C and triethylamine and low-boiling substances were removed by reduced pressure distillation, and the temperature was lowered to room temperature. A phosphorus-containing triaziridine crosslinking agent was obtained; 174 g of 1-(2-hydroxyethyl)aziridine and 124 g of dimethyl methylphosphonate (molar ratio 2:1) were poured into a container and mixed, 12 g of triethylamine catalyst was added, the temperature was raised to 60 °C, after reacting for 20 hours, the temperature was raised to 100 °C and triethylamine and low-boiling substances were removed by reduced pressure distillation, and the temperature was lowered to room temperature. A phosphorus-containing bisaziridine crosslinking agent was obtained. 100 g of the phosphorus-containing triaziridine crosslinking agent was mixed with 50 g of the phosphorus-containing bisaziridine crosslinking agent to obtain a phosphorus-containing polyaziridine crosslinking agent.

[0189] Mixing: 80 g of the flame retardant dispersion was mixed with 100 g of the polyacrylate emulsion, and after stirring and mixing evenly, 5 g of the phosphorus-containing polyaziridine crosslinking agent was added. The pH value of the coating was adjusted to 8.5 using 25% ammonia water. Then 2 g of a 1.5% aqueous solution of hydroxypropyl methylcellulose was added. After mixing evenly, polyacrylate flame retardant coating 3 was obtained.

[0190] Flame retardant polyester 3 was prepared according to the coating method in Example 3 and relevant tests were carried out. All the test results are shown in Table 15.

[0191] Table 15 Performance test results of flame retardant polyester 3

[0192]

[0193]

[0194] It can be seen from Table 15 that the limiting oxygen index of the prepared flame retardant polyester 3 exceeded 28% before and after washing, the afterflame time and the smoldering time were both 0 s, and there was no molten drop during combustion, reaching Class B1 in the test standard, and flame retardant polyester 3 showed good flame retardant performance.

[0195] Example 4

[0196] (1) Preparation of the polyacrylate emulsion

[0197] Preparation of mixed monomers: 3700 g of ethyl acrylate, 5500 g of butyl acrylate, 800 g of isooctyl acrylate, 1000 g of methyl methacrylate, 400 g of monomer C and 500 g of 2-hydroxyethyl methacrylate were mixed evenly to obtain the mixed monomers. Monomer C is a mixture of maleic acid and acrylic acid.

[0198] Polymerization: An emulsifier composed of 140 g of sodium dodecyl sulfate and 560 g of OP-10, 10000 g of mixed monomers and 10000 g of water were emulsified using a homogenizer to prepare a reactant emulsion. Under nitrogen protection, 3105 g of the reactant emulsion was added to the reaction kettle, and 93.15 g of an initiator aqueous solution was added dropwise with stirring. The initiator aqueous solution contained 13.9725 g of ammonium persulfate, 4.6575 g of sodium bisulfite, and 74.52 g of water. The weight of the initiator was 0.6% of the weight of the reactant emulsion added to the reaction kettle at this time. The reaction kettle was heated to 70 °C and reacted for 2 hours, then the remaining 17595 g of the reactant emulsion was added to the reaction kettle, and 2463.3 g of the initiator aqueous solution was added dropwise again. The initiator aqueous solution contained 263.925 g of ammonium persulfate, 87.975 g of sodium bisulfite, and 2111.4 g of water. The weight of the initiator was 2% of the weight of the reactant emulsion added to the reaction kettle again at this time. The temperature of the reaction kettle was raised to 80 °C and reacted for 2 hours. Then the temperature of the reaction kettle was raised to 85 °C and reacted for 0.5 hours. The reaction kettle was cooled to room temperature, and the obtained product was filtered to finally obtain a polyacrylate emulsion.

[0199] (2) Preparation of flame retardant dispersion

[0200] Preparation of compound flame retardant: 200 g of aluminum diethyl phosphinate, 6 g of melamine cyanurate, and 20 g of piperazine pyrophosphate were mixed evenly to prepare the compound flame retardant.

[0201] Preparation of flame retardant dispersion: 0.6 g of W-806 defoamer was mixed evenly with 100 g of water, and then 6 g of surfactant was added to form a uniform surfactant aqueous solution. The surfactant used was fatty alcohol polyoxyethylene ether, and its molecular structural formula was C 11 H 23 (OCH2CH2) m OH, its number average molecular weight was 524, and the ratio of its weight average molecular weight to the number average molecular weight was 1. 160 g of the compound flame retardant was added to the prepared surfactant aqueous solution, and ultrasonic dispersion treatment was used to make the flame retardant evenly dispersed in the surfactant aqueous solution to prepare the flame retardant dispersion.

[0202] (3) Preparation of flame retardant coating

[0203] The preparation method of the phosphorus-containing polyaziridine crosslinking agent is as follows: Pour 261 grams of 1-(2-hydroxyethyl)aziridine and 140 grams of trimethyl phosphate (molar ratio 3:1) into a container and mix them. Add 20 grams of triethylamine catalyst, heat up to 60 °C, after reacting for 20 hours, heat up to 90 °C and distill off triethylamine and low-boiling substances under reduced pressure, then cool down to room temperature. A phosphorus-containing triaziridine crosslinking agent is obtained; Pour 174 grams of 1-(2-hydroxyethyl)aziridine and 124 grams of dimethyl methylphosphonate (molar ratio 2:1) into a container and mix them. Add 12 grams of triethylamine catalyst, heat up to 60 °C, after reacting for 20 hours, heat up to 100 °C and distill off triethylamine and low-boiling substances under reduced pressure, then cool down to room temperature. A phosphorus-containing bisaziridine crosslinking agent is obtained. Take 100 grams of the phosphorus-containing triaziridine crosslinking agent and mix it with 120 grams of the phosphorus-containing bisaziridine crosslinking agent to obtain the phosphorus-containing polyaziridine crosslinking agent.

[0204] Mixing: Take 110 grams of the flame retardant dispersion and mix it with 100 grams of the polyacrylate emulsion. After stirring and mixing evenly, add 3 grams of the phosphorus-containing polyaziridine crosslinking agent. Use 25% ammonia water to adjust the pH value of the coating to 8.5. Then add 1.5 grams of a 1.5% aqueous solution of hydroxypropyl methylcellulose. Mix evenly to obtain the polyacrylate flame retardant coating 4.

[0205] Prepare the flame retardant polyester 4 according to the coating method in Example 1 and conduct relevant tests. All the test results are shown in Table 16.

[0206] Table 16 Performance test results of the flame retardant polyester 4

[0207]

[0208] It can be seen from Table 16 that the oxygen index of the prepared flame retardant polyester 4 exceeds 29% before and after washing, the afterflame time and the smoldering time are both 0 seconds, and there is no molten drop during combustion, reaching the B1 level in the test standard. The flame retardant polyester 4 shows good flame retardant performance.

[0209] Example 5

[0210] (1) Preparation of the polyacrylate emulsion

[0211] Preparation of the mixed monomers: Take 30 grams of ethyl acrylate, 55 grams of butyl acrylate, 15 grams of isooctyl acrylate, 9 grams of methyl methacrylate, 4 grams of fumaric acid and 4.5 grams of monomer D and mix them evenly to obtain the mixed monomers. Among them, monomer D is a mixture of N-methylolacrylamide, hydroxyethyl acrylate and hydroxyethyl methacrylate.

[0212] Aggregation: An emulsifier composed of 0.6 g of sodium dodecyl sulfate and 2.4 g of OP-10, 100 g of mixed monomers, and 100 g of water were emulsified using a homogenizer to prepare a reactant emulsion. Under nitrogen protection, 40 g of the reactant emulsion was added to a reaction kettle, and 8 g of an initiator aqueous solution was added dropwise with stirring. The initiator aqueous solution contained 0.6 g of ammonium persulfate, 0.2 g of sodium bisulfite, and 7.2 g of water. The weight of the initiator was 2% of the weight of the reactant emulsion added to the reaction kettle at this time. The reaction kettle was heated to 50 °C and reacted for 2 hours, then the remaining 165 g of the reactant emulsion was added to the reaction kettle, and 33 g of the initiator aqueous solution was added dropwise again. The initiator aqueous solution contained 2.475 g of ammonium persulfate, 0.825 g of sodium bisulfite, and 29.7 g of water. The weight of the initiator was 2% of the weight of the reactant emulsion added to the reaction kettle again at this time. The temperature of the reaction kettle was raised to 80 °C and reacted for 2 hours. Then the temperature of the reaction kettle was raised to 85 °C and reacted for 0.5 hours. The reaction kettle was cooled to room temperature, and the obtained product was filtered to finally obtain a polyacrylate emulsion.

[0213] (2) Preparation of flame retardant dispersion

[0214] Preparation of compound flame retardant: 200 g of aluminum diethylphosphinate, 2 g of melamine cyanurate, and 22 g of aluminum hypophosphite were mixed evenly to prepare a compound flame retardant.

[0215] Preparation of flame retardant dispersion: 0.3 g of GB-110 defoamer was mixed evenly with 100 g of water, and then 8 g of surfactant was added to form a uniform surfactant aqueous solution. The surfactant used was fatty alcohol polyoxyethylene ether, and its molecular structural formula was C9H 19 (OCH2CH2) m OH, its number average molecular weight was 493, and the ratio of its weight average molecular weight to the number average molecular weight was 1.1. 170 g of the compound flame retardant was added to the prepared surfactant aqueous solution, and ultrasonic dispersion treatment was used to make the flame retardant evenly dispersed in the surfactant aqueous solution to prepare a flame retardant dispersion.

[0216] (3) Preparation of flame retardant coating

[0217] The preparation method of the phosphorus-containing polyaziridine crosslinking agent is as follows: Pour 261 grams of 1-(2-hydroxyethyl)aziridine and 140 grams of trimethyl phosphate (molar ratio 3:1) into a container and mix them. Add 20 grams of triethylamine catalyst, heat up to 70°C, after reacting for 15 hours, heat up to 95°C and distill under reduced pressure to remove triethylamine and low-boiling substances, and then cool down to room temperature. A phosphorus-containing triaziridine crosslinking agent is obtained; Pour 174 grams of 1-(2-hydroxyethyl)aziridine and 124 grams of dimethyl methylphosphonate (molar ratio 2:1) into a container and mix them. Add 12 grams of triethylamine catalyst, heat up to 70°C, after reacting for 15 hours, heat up to 95°C and distill under reduced pressure to remove triethylamine and low-boiling substances, and then cool down to room temperature. A phosphine-containing diaziridine crosslinking agent is obtained. Take 100 grams of the phosphorus-containing triaziridine crosslinking agent and mix it with 120 grams of the phosphine-containing diaziridine crosslinking agent to obtain the phosphorus-containing polyaziridine crosslinking agent.

[0218] Mixing: Take 130 grams of the flame retardant dispersion and mix it with 100 grams of the polyacrylate emulsion. After stirring and mixing evenly, add 5 grams of the phosphorus-containing polyaziridine crosslinking agent. Use 25% ammonia water to adjust the pH value of the coating to 8.5. Then add 1 gram of a 1.5% aqueous solution of hydroxypropyl methylcellulose. Mix evenly to obtain the polyacrylate flame retardant coating 5.

[0219] Prepare the flame retardant polyester 5 according to the coating method in Example 1 and conduct relevant tests. All the test results are shown in Table 17.

[0220] Table 17 Performance test results of the flame retardant polyester 5

[0221]

[0222]

[0223] As can be seen from Table 17, the oxygen index of the prepared flame retardant polyester 5 exceeds 29% before and after washing, the afterflame time and the smoldering time are both 0 seconds, and there is no molten drop during combustion, reaching the B1 level in the test standard. The flame retardant polyester 5 exhibits good flame retardant performance.

[0224] Comparative Example 21

[0225] Mixing step in the preparation of the flame retardant coating in Example 5: Take 70 grams of the flame retardant dispersion and mix it with 100 grams of the polyacrylate emulsion. After stirring and mixing evenly, add 5 grams of the phosphorus-containing polyaziridine crosslinking agent. Use 25% ammonia water to adjust the pH value of the coating to 8.5. Then add 1 gram of a 1.5% aqueous solution of hydroxypropyl methylcellulose. Mix evenly to obtain the polyacrylate flame retardant coating D21.

[0226] Prepare the flame retardant polyester D21 according to the coating method in Example 1 and conduct relevant tests. All the test results are shown in Table 18.

[0227] Table 18 Performance Test Results of Flame Retardant Polyester D21

[0228]

[0229] As can be seen from Table 18, the limiting oxygen index of the prepared flame retardant polyester D21 before and after washing is lower than 25%, with continuous burning and smoldering phenomena, and the char length exceeds 15 cm, reaching Class B2 in the test standard. The flame retardant performance of flame retardant polyester D21 is worse than that of flame retardant polyester 5. This is due to the relatively small addition amount of the flame retardant dispersion liquid.

[0230] Comparative Example 22

[0231] Mixing step in the preparation of the flame retardant coating in Example 5: Take 140 g of the flame retardant dispersion liquid and mix it with 100 g of the polyacrylate emulsion. After stirring and mixing evenly, add 5 g of the phosphorus-containing polyaziridine crosslinking agent. Use 25% ammonia water to adjust the pH value of the coating to 8.5. Then add 1 g of a 1.5% aqueous solution of hydroxypropyl methylcellulose. After mixing, polyacrylate flame retardant coating D22 is obtained.

[0232] Gel-like particles appeared after the mixing of polyacrylate flame retardant coating D22. The flame retardant polyester D22 was prepared according to the coating method in Example 1, but during the coating process, the phenomenon of uneven coating and incomplete coverage of some polyester fabrics by the coating occurred. Therefore, relevant tests cannot be carried out.

[0233] Example 6

[0234] When preparing the flame retardant dispersion liquid in Example 5, the compounded flame retardant was prepared by mixing 200 g of aluminum diethylphosphinate, 2 g of melamine cyanurate, 10 g of aluminum hypophosphite, 5 g of ammonium polyphosphate, and 7 g of melamine polyphosphate evenly. Other procedures are the same as in Example 5.

[0235] Finally, after mixing evenly, polyacrylate flame retardant coating 6 is obtained.

[0236] The flame retardant polyester 6 was prepared according to the coating method in Example 1 and relevant tests were carried out. All the test results are shown in Table 19.

[0237] Table 19 Performance Test Results of Flame Retardant Polyester 6

[0238]

[0239] As can be seen from Table 19, the limiting oxygen index of the prepared flame retardant polyester 6 exceeds 29% before and after washing, the continuous burning time and the smoldering time are both 0 s, and there is no molten drop during burning, reaching Class B1 in the test standard. The flame retardant polyester 6 exhibits good flame retardant performance.

[0240] Comparative Example 23

[0241] When preparing the flame retardant dispersion liquid in Example 5, 100 grams of the compound flame retardant was added to the prepared aqueous surfactant solution, and ultrasonic dispersion treatment was used to uniformly disperse the flame retardant into the aqueous surfactant solution, thereby preparing the flame retardant dispersion liquid. Others are the same as in Example 5.

[0242] Finally, it was mixed evenly to obtain the polyacrylate flame retardant coating D23.

[0243] The flame retardant polyester D23 was prepared according to the coating method in Example 1, and relevant tests were carried out. All the test results are shown in Table 20.

[0244] Table 20 Performance test results of the flame retardant polyester D23

[0245]

[0246] It can be seen from Table 20 that the oxygen index of the prepared flame retardant polyester D23 is lower than 24% after washing, the afterflame time is greater than 5 seconds, and there is no molten drop during combustion, reaching the B2 level in the test standard. During the preparation of the flame retardant polyester D23, when preparing the polyacrylate flame retardant coating, the weight ratio of the compound flame retardant to water is 1:1, and the amount of the compound flame retardant added is small, so the flame retardant performance is worse than that of the flame retardant polyester 5.

[0247] Comparative Example 24

[0248] When preparing the flame retardant dispersion liquid in Example 5, 190 grams of the compound flame retardant was added to the prepared aqueous surfactant solution, and ultrasonic dispersion treatment was used. It was found that part of the flame retardant floated on the surface of the solution and the complete uniform dispersion of the flame retardant could not be achieved.

[0249] Others are the same as in Example 5. Finally, a uniformly mixed polyacrylate flame retardant coating could not be prepared. This is because when preparing the polyacrylate flame retardant coating, the weight ratio of the compound flame retardant to water is 1.9:1, and the added compound flame retardant is in excess.

[0250] Comparative Example 25

[0251] In Example 2, pentaerythritol tris(3-aziridinyl) propionate, a non-phosphorus polyaziridine crosslinking agent, was used to replace the phosphorus-containing polyaziridine crosslinking agent.

[0252] Others are the same as in Example 2. Finally, it was mixed evenly to obtain the polyacrylate flame retardant coating D25.

[0253] The flame retardant polyester D25 was prepared according to the coating method in Example 1, and relevant tests were carried out. All the test results are shown in Table 21.

[0254] Table 21 Performance test results of the flame retardant polyester D25

[0255]

[0256] As can be seen from Table 21, the limiting oxygen index of the prepared flame-retardant polyester D25 before and after washing is lower than 26%, the afterflame time is greater than 5 seconds, and there is no molten dripping during combustion, reaching the B2 level in the test standard. The flame-retardant performance of flame-retardant polyester D25 is poorer than that of flame-retardant polyester 2. Using a phosphorus-free crosslinking agent, the finally prepared flame-retardant polyester has a relatively low flame-retardant performance.

[0257] Comparative Example 26

[0258] In the preparation step of the flame-retardant coating in Example 4, when mixing, 3 g of a phosphorus-containing polyaziridine crosslinking agent was taken and mixed with 100 g of a polyacrylate emulsion. After stirring and mixing evenly, 110 g of a flame retardant dispersion was added.

[0259] Others are the same as in Example 4. After mixing evenly, polyacrylate flame-retardant coating D26 was obtained.

[0260] Flame-retardant polyester D26 was prepared according to the coating method in Example 1 and relevant tests were carried out. All the test results are shown in Table 22.

[0261] Table 22 Performance test results of flame-retardant polyester D26

[0262]

[0263] As can be seen from Table 22, the afterflame time of the prepared flame-retardant polyester D26 exceeds 5 seconds after washing, reaching the B2 level in the test standard. The flame-retardant performance of flame-retardant polyester D26 is poorer than that of flame-retardant polyester 4. This is because mixing the phosphorus-containing polyaziridine crosslinking agent with the polyacrylate emulsion first will cause a crosslinking reaction between the crosslinking agent and the emulsion in the absence of the flame retardant, reducing the degree of crosslinking and adhesion between the flame retardant and the emulsion, resulting in more loss of the flame retardant during the washing process.

Claims

1. A preparation method of a halogen-free flame retardant coating for polyester fabrics, characterized in that The steps are as follows: (1)Preparation of polyacrylate emulsion The emulsifier, mixed monomers and water are emulsified using a homogenizer to prepare a reactant emulsion; under nitrogen protection, a part of the reactant emulsion is added to the reaction kettle, and then an initiator aqueous solution is added dropwise for the first time under stirring. The reaction kettle is heated to 50 - 70 °C and reacted for 1 - 2 hours. Then the remaining reactant emulsion is added to the reaction kettle, and the initiator aqueous solution is added dropwise for the second time. The temperature of the reaction kettle is raised to 80 °C and reacted for 2 - 4 hours. Then the temperature of the reaction kettle is raised to 85 °C and reacted for 0.5 hour; then the reaction kettle is cooled to room temperature, and the obtained product is filtered to finally obtain a polyacrylate emulsion; (2)Preparation of flame retardant dispersion The defoamer and water are mixed, and then a surfactant is added to form a uniform surfactant aqueous solution; the flame retardant is added to the surfactant aqueous solution; ultrasonic dispersion treatment is used to uniformly disperse the flame retardant into the surfactant aqueous solution to prepare a flame retardant dispersion; (3)Preparation of flame retardant coating The flame retardant dispersion and the polyacrylate emulsion are mixed in a weight ratio of (0.8 - 1.3):1, and after stirring and mixing evenly, a phosphorus-containing polyaziridine crosslinking agent is added. The weight ratio of the phosphorus-containing polyaziridine crosslinking agent to the polyacrylate emulsion is (0.01 - 0.05):1; the pH value of the coating is adjusted to 8 - 9 using 25% ammonia water; then a 1.5% aqueous solution of hydroxypropyl methylcellulose is added. The weight ratio of hydroxypropyl methylcellulose to the polyacrylate emulsion is (0.005 - 0.02):1, and after mixing evenly, a polyacrylate flame retardant coating is obtained.

2. The preparation method of a halogen-free flame retardant coating for polyester fabrics according to claim 1, characterized in that In the step (1), the weight ratio of the emulsifier, monomer and water is (3 - 7):100:100; The reactant emulsion added to the reaction kettle for the first time is 15 - 30% of the total weight. The weight ratio of the initiator to water in the initiator aqueous solution added dropwise for the first time is 1:(4 - 9), and the weight of the initiator is 0.6 - 2% of the weight of the reactant emulsion added to the reaction kettle at this time; The weight ratio of the initiator to water in the initiator aqueous solution added dropwise for the second time is 1:(4 - 9), and the weight of the initiator is 0.6 - 2% of the weight of the reactant emulsion added to the reaction kettle again at this time.

3. The preparation method of a halogen-free flame retardant coating for polyester fabrics according to claim 2, wherein The emulsifier is a mixture of sodium dodecyl sulfate and OP - 10, and the weight ratio of the two is 1:4; the initiator used is a mixture of ammonium persulfate and sodium bisulfite, and the weight ratio of the two is 3:

1.

4. The preparation method of a halogen-free flame retardant coating for polyester fabrics according to claim 1, characterized in that In the step (1), the mixed monomers include four types, namely A, B, C, and D, and the weight ratio of the four types is 100:(9 - 11):(3 - 5):(4 - 5); the monomer of type A includes ethyl acrylate, butyl acrylate, and isooctyl acrylate, and the weight ratio of ethyl acrylate, butyl acrylate, and isooctyl acrylate is 1:(2 - 0.5):(0.5 - 0); the monomer of type B is methyl methacrylate; the monomer of type C includes one or a mixture of more of acrylic acid, methacrylic acid, maleic acid, and fumaric acid; the monomer of type D includes one or a mixture of more of N-methylolacrylamide, hydroxyethyl acrylate, and hydroxyethyl methacrylate.

5. The preparation method of a halogen-free flame retardant coating for polyester fabrics according to claim 1, wherein The weight ratio of the defoamer, surfactant, flame retardant to water is (0.003 - 0.008):(0.02 - 0.08):(1.2 - 1.7):1; the surfactant is fatty alcohol polyoxyethylene ether, and its molecular structural formula is C n H 2n+1 (OCH2CH2) m OH, where n is an integer greater than 5 and less than 14. It is required that the number-average molecular weight of the fatty alcohol polyoxyethylene ether is greater than 366 and less than 684, and the ratio of its weight-average molecular weight to the number-average molecular weight is less than 2.

6. The preparation method of a halogen-free flame retardant coating for polyester fabrics according to claim 1, characterized in that The flame retardant is a compound flame retardant, including three components: aluminum diethylphosphinate, melamine cyanurate, and other halogen-free flame retardants. The weight ratio of aluminum diethylphosphinate, melamine cyanurate, and other halogen-free flame retardants is 100:(1 - 5):(5 - 12); the other halogen-free flame retardants are a mixture of one or more of phytic acid-containing flame retardants, ammonium polyphosphate, piperazine pyrophosphate, melamine polyphosphate, and aluminum hypophosphite.

7. The preparation method of a halogen-free flame retardant coating for polyester fabrics according to claim 6, characterized in that The preparation method of the phytic acid-containing flame retardant is as follows: Mix phytic acid, melamine, and water in a weight ratio of 1:0.76:10, stir and react at 80 °C for 24 hours, adjust the pH value of the above reaction solution to 7 with piperazine, and obtain the phytic acid-containing flame retardant through spray drying.

8. The preparation method of a halogen-free flame retardant coating for polyester fabrics according to claim 1, wherein The preparation method of the phosphorus-containing polyaziridine crosslinking agent is as follows: Pour 1-(2-hydroxyethyl)aziridine and trimethyl phosphate into a container in a molar ratio of 3:1, add a triethylamine catalyst, heat up to 60 - 80 °C, react for 10 - 20 hours, then heat up to 90 - 100 °C and distill off triethylamine and low-boiling substances under reduced pressure, and cool to room temperature to obtain the phosphorus-containing triaziridine crosslinking agent for use; then pour 1-(2-hydroxyethyl)aziridine and dimethyl methylphosphonate into a container and mix, add a triethylamine catalyst, heat up to 60 - 80 °C, react for 10 - 20 hours, then heat up to 90 - 100 °C and distill off triethylamine and low-boiling substances under reduced pressure, and cool to room temperature to obtain the phosphorus-containing diaziridine crosslinking agent for use; mix the phosphorus-containing triaziridine crosslinking agent and the phosphorus-containing diaziridine crosslinking agent in a weight ratio of 100:(50 - 150) to obtain the phosphorus-containing polyaziridine crosslinking agent.

9. The preparation method of a halogen-free flame retardant coating for polyester fabrics according to claim 8, characterized in that The weight of the added triethylamine catalyst is 3 - 5% of the total weight of 1-(2-hydroxyethyl)aziridine and trimethyl phosphate; 1-(2-hydroxyethyl)aziridine and dimethyl methylphosphonate are in a molar ratio of 2:1, and the added triethylamine catalyst is 3 - 5% of the total weight of 1-(2-hydroxyethyl)aziridine and dimethyl methylphosphonate.

10. The preparation method of a halogen-free flame retardant coating for polyester fabrics according to claim 6, characterized in that The defoamer is an organosilicon defoamer, a polyether defoamer, or a polyether-modified silicone defoamer.

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