Flame retardant and preparation method of flame-retardant spandex

Abstract

The invention discloses a flame retardant and a preparation method of flame-retardant spandex. The structure of the flame retardant comprises a C-N six-membered ring or an N-P six-membered ring, siloxane and hydroxyl; a C-N six-membered ring and an N-P six-membered ring are one of cyanuric acid, a triazine ring and a phosphazene ring; a hydrogen part on a six-membered ring is substituted by pentaerythritol phosphate, hydroxymethyl dimethyl phosphite, diphenyl phosphoric acid, dimethyl phosphoric acid and diphenyl phosphate. A reaction product of the flame retardant, polytetramethylene ether glycol and a diisocyanate compound is used for preparing polyether type flame-retardant spandex; the preparation method comprises the following steps: mixing a flame retardant with dibasic acid and dihydric alcohol, carrying out condensation polymerization under the action of a catalyst to prepare flame-retardant polyester dihydric alcohol, and then using a reaction product of the flame-retardant polyester dihydric alcohol and a diisocyanate compound to prepare the polyester type flame-retardant spandex. By adding a small amount of the flame retardant, the oxygen index of the spandex can be greatly increased, molten drops can be reduced, and the flame retardance and the washing resistance are good.

Description

Technical Field

[0001] The invention relates to the technical field of textiles, in particular to a flame retardant and a method for preparing the flame retardant spandex. Background Art

[0002] Spandex is a polyurethane elastic fiber with properties similar to rubber, such as high elasticity and high elongation. It can be used in clothing that needs to have stretch elasticity while meeting comfort requirements, such as professional sportswear, fitness clothing and exercise clothing, surgical protective clothing, performance clothing, etc. However, the limiting oxygen index of spandex is only 18%, and it burns very quickly. Even when blended with other flame-retardant fibers, its flammability will seriously affect the flame-retardant properties of flame-retardant fabrics and fabrics, which limits its application in the field of flame-retardant textiles.

[0003] Chinese patent CN103590138B discloses a method for preparing flame-retardant polyurethane elastic fiber, wherein a phosphorus-based flame retardant containing hydroxyl and carboxyl groups is embedded in the main chain of spandex molecules during the chain extension process as a reactive flame retardant, and a melamine-based flame retardant and an aluminum oxide flame retardant are mixed with a polyurethane stock solution as additive flame retardants and prepared by dry spinning. CN106283265B inserts an alkyl alcohol amine chain extender into the interlayer of ZrP, and then participates in the chain extension of a polyurethane prepolymer to prepare a zirconium phosphate synergistic flame retardant spandex. CN105420844B discloses a method for preparing flame-retardant spandex fiber, wherein a halogen-free phosphorus-based flame retardant of a phenylphosphonate and a synergistic flame retardant of a non-metallic oxide are added to a polyurethane polymer solution to obtain flame-retardant spandex. The oxygen index of spandex fiber can be improved to a certain extent by introducing phosphorus-containing substances into the main chain and adding additive flame retardants to spandex, but a large amount of flame retardants need to be added, and anti-drip has not been effectively solved. Summary of the invention

[0004] In view of the above problems existing in the prior art, the present invention provides a flame retardant and a method for preparing flame retardant spandex thereof. The present invention adopts an in-situ polymerization process to achieve the addition of a small amount of flame retardant, which can significantly improve the oxygen index of spandex and reduce droplets, and has good flame retardancy and water washability, and improves the low temperature flexibility and thermal stability of spandex.

[0005] The technical solution of the present invention is as follows:

[0006] The first object of the present invention is to provide a flame retardant, wherein the structure of the flame retardant contains a CN six-membered ring or a NP six-membered ring, siloxane and a hydroxyl group;

[0007] The CN six-membered ring and the NP six-membered ring are one of cyanuric acid ring, triazine ring and phosphazene ring;

[0008] The hydrogen portions on the CN six-membered ring and the NP six-membered ring are replaced by pentaerythritol phosphate, dimethyl hydroxymethyl phosphite, diphenyl phosphate, dimethyl phosphate, and diphenyl phosphate.

[0009] In one embodiment of the present invention, the structure of the flame retardant is shown in general formula (1):

[0010]

[0011] In the general formula (1), Y represents a C or P element; m and n represent integers of 1 to 3 respectively;

[0012] R1 is independently H, hydroxymethyl, hydroxyethyl, One of;

[0013] R2 is independently represented by H, hydroxyl, One or more of;

[0014] Two adjacent R1s are the same or different; two adjacent R2s are the same or different;

[0015] At least one of R1 and R2 is a phosphorus-containing substituent.

[0016] In one embodiment of the present invention, m and n are 1, 2 or 3 respectively.

[0017] In one embodiment of the present invention, the flame retardant structure is any one of the following structures:

[0018]

[0019]

[0020] The second object of the present invention is to provide a method for preparing the flame retardant, comprising the following steps:

[0021] Under nitrogen protection, trihydroxy CN hexacyclic ring or NP hexacyclic ring, triethylamine are dissolved in an organic solvent, phosphorus oxychloride is dissolved in an organic solvent, the two solutions are mixed and reacted fully, a dichlorosilane-containing material is dissolved in an organic solvent, the above reaction solution is added, and the reaction is carried out at 80-90° C. for 5-12 hours. Finally, the reaction mixture is cooled, washed, and dried under reduced pressure to obtain the inhibitor.

[0022] In one embodiment of the present invention, the molar ratio of the trihydroxy CN six-membered ring or the NP six-membered ring to the phosphorus oxychloride is 1:1.

[0023] In one embodiment of the present invention, the molar ratio of the dichlorosiloxane-based material to the trihydroxy CN six-membered ring or NP six-membered ring is 1:2.

[0024] The third object of the present invention is to provide a flame retardant polyester diol prepared by the flame retardant, wherein the flame retardant is mixed with a dibasic acid and a diol, and a polycondensation reaction is carried out under the action of a catalyst to obtain a flame retardant polyester diol.

[0025] The fourth object of the present invention is to provide a method for preparing a flame retardant polyester diol from the flame retardant, comprising the following steps: the flame retardant is mixed with a dibasic acid and a diol, and a catalyst is added, and stirred at 160-190°C under nitrogen protection, and the esterification reaction ends when no water is produced. Then the temperature is raised to 180-280°C again, and a polycondensation reaction is carried out at -0.1MPa for 2-6h to obtain a flame retardant polyester diol with a molecular weight of 1600-3000 and end-capped with terminal hydroxyl groups.

[0026] In one embodiment of the present invention, the dibasic acid is one or more of terephthalic acid (PTA), phthalic acid (PA), isophthalic acid (PIA), naphthalene dicarboxylic acid (NDA), cyclohexanedicarboxylic acid (CHDA), malonic acid (MA), succinic acid (SA), glutaric acid (GA), adipic acid (H2A), pimelic acid, suberic acid, sebacic acid, dodecanedioic acid (DDCA), 2,5-furandicarboxylic acid (FDCA), and itaconic acid (IA); the diol is one or more of ethylene glycol (EG), 1,2-propylene glycol (PG), 2-methylpropanediol (MPD), 1,3-propylene glycol (PDO), 1,4-butanediol (BDO), and neopentyl glycol (NPG); and the catalyst is one or more of antimony trioxide, antimony acetate, tetrabutyl titanate, titanium ethylene glycol, stannous octoate, and triethylaluminum.

[0027] In one embodiment of the present invention, the molar ratio of the flame retardant, the dibasic acid, and the diol is 0.5-1:10:9.5-10.

[0028] The fifth object of the present invention is to provide an application of the flame retardant mentioned above for preparing polyether flame retardant spandex.

[0029] The sixth object of the present invention is to provide a polyether flame-retardant spandex prepared by the above flame retardant, and the reaction product of the above flame retardant with polytetramethylene ether glycol and diisocyanate compound is used to prepare spinning solution.

[0030] The seventh object of the present invention is to provide a method for preparing polyether flame retardant spandex with the above flame retardant, comprising the following steps:

[0031] (1) polytetramethylene ether glycol, diisocyanate compound and the flame retardant are mixed in proportion and reacted at 89-109° C. for 90-130 min to form a prepolymer solution;

[0032] (2) The prepolymer solution is cooled to 8-10° C., and mixed amine is added under stirring conditions to carry out chain extension reaction and chain termination reaction to form a high viscosity polymer;

[0033] (3) The high viscosity polymer is mixed with an anti-yellowing agent, a matting agent, an antioxidant, and magnesium stearate to form a spinning solution:

[0034] (4) After the spinning solution is matured, the polyether flame-retardant spandex is spun using a dry spinning system.

[0035] In one embodiment of the present invention, the diisocyanate compound is selected from one or more of 4,4'-diphenylmethane diisocyanate (4,4-MDI), 2,4'-diphenylmethane diisocyanate (2,4-MDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), dicyclohexylmethane-4,4'-diisocyanate (HMDI), and tetramethylxylene diisocyanate (TMXDI).

[0036] In one embodiment of the present invention, the molecular weight of polytetramethylene ether glycol is 1800-3000.

[0037] In one embodiment of the present invention, the molar ratio of isocyanate of the diisocyanate compound to the total hydroxyl groups of polytetramethylene ether glycol (PTMEG) and the flame retardant is 1.4-2.1, and the molar ratio of hydroxyl groups of polytetramethylene ether glycol (PTMEG) and the flame retardant is 1-10.

[0038] In one embodiment of the present invention, the mixed amine is composed of a chain extender and a terminator; the chain extender is selected from one or more of ethylenediamine, pentamethylenediamine, malonic acid hydrazide, and adipic acid dihydrazide, and the terminator is selected from one or more of diethylamine, dipropylamine, cyclohexylamine, n-butanol, and ethanolamine.

[0039] The eighth object of the present invention is to provide an application of the flame-retardant polyester diol for preparing polyester-type flame-retardant spandex.

[0040] The ninth object of the present invention is to provide a polyester-type flame-retardant spandex prepared from the flame-retardant polyester diol, wherein the reaction product of the flame-retardant polyester diol and the diisocyanate compound is used to prepare a spinning solution.

[0041] The tenth object of the present invention is to provide a method for preparing polyester-type flame-retardant spandex using the flame-retardant polyester diol, comprising the following steps:

[0042] (1) The flame retardant polyester diol and the diisocyanate compound are mixed in proportion and reacted at 89-109° C. for 90-130 minutes to form a prepolymer solution;

[0043] (2) The prepolymer solution is cooled to 8-10° C., and mixed amine is added under stirring conditions to carry out chain extension reaction and chain termination reaction to form a high viscosity polymer;

[0044] (3) the high viscosity polymer is mixed with an anti-yellowing agent, a matting agent, an antioxidant, and magnesium stearate to form a spinning solution;

[0045] (4) After the spinning solution is matured, polyester flame-retardant spandex is spun using a dry spinning system.

[0046] In one embodiment of the present invention, the diisocyanate compound is selected from one or more of 4,4'-diphenylmethane diisocyanate (4,4-MDI), 2,4'-diphenylmethane diisocyanate (2,4-MDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), dicyclohexylmethane-4,4'-diisocyanate (HMDI), and tetramethylxylene diisocyanate (TMXDI).

[0047] In one embodiment of the present invention, the molar ratio of the isocyanate of the diisocyanate compound to the hydroxyl group of the flame retardant polyester diol is 1.4-2.1.

[0048] In one embodiment of the present invention, the mixed amine is composed of a chain extender and a terminator; the chain extender is selected from one or more of ethylenediamine, pentamethylenediamine, malonic acid hydrazide, and adipic acid dihydrazide, and the terminator is selected from one or more of diethylamine, dipropylamine, cyclohexylamine, n-butanol, and ethanolamine.

[0049] The beneficial technical effects of the present invention are:

[0050] The present invention adopts an in-situ polymerization process to add a small amount of flame retardant to greatly improve the oxygen index of spandex and reduce droplets, and the flame retardant performance is good in water washing resistance, and the low-temperature flexibility and thermal stability of spandex are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is the structure of the flame retardant of the present invention. DETAILED DESCRIPTION

[0052] The present invention is described in detail below in conjunction with the accompanying drawings and embodiments.

[0053] Example 1: Flame retardant

[0054]

[0055] THEIC(DPPC)-TMSOME-THEIC(DPPC): Under nitrogen protection, 26.12g 1,3,5-tris(2-hydroxyethyl)cyanuric acid (THEIC) and 27.8mL triethylamine were dissolved in 150mL DMF; 23.66g diphenylphosphinyl chloride (DPPC) was dissolved in 120mL DMF and slowly added dropwise to the THEIC solution for 8h. After that, 11.56g 1,3-bis(chloromethyl)-1,1,3,3-tetramethyldisiloxane (TMSOME) was dissolved in 150mL DMF and slowly added dropwise to the above reaction solution, and refluxed at 80°C for 8h. The precipitate was washed five times with distilled water and acetone. The reaction mixture was cooled, washed, and dried under reduced pressure to obtain THEIC(DPPC)-TMSOME-THEIC(DPPC).

[0056] Example 2: Flame Retardant

[0057]

[0058] TPTEPZ(DPC)-BTD-TPTEPZ(DPC): Under nitrogen protection, 59.72g of 2,4,6-triphenyloxy-2,4,6-tris(hydroxyethoxy)cyclotriphosphazene (TPTEPZ) and 27.8mL of triethylamine were dissolved in 150mL of THF and cooled in an ice-water bath. 14.45g of dimethylphosphoryl chloride (DPC) was dissolved in 120mL of THF and slowly added dropwise to the THEIC solution for 6h. After that, 14.36g of 1,3-bis(3-chloropropyl)-1,1,3,3-tetramethyldisiloxane (BTD) was dissolved in 120mL of THF and slowly added dropwise to the above reaction solution, and refluxed at 90°C for 10h. The reaction mixture was cooled, washed, and dried under reduced pressure to obtain TPTEPZ(DPC)-BTD-TPTEPZ(DPC).

[0059] Example 3: Flame retardant

[0060]

[0061] CA(DCP)-BTD-CA(DPC): Under nitrogen protection, 12.91g triazine alcohol (CA) and 27.8mL triethylamine were dissolved in 150mL THF and cooled in an ice-water bath. 26.86g diphenyl chlorophosphate (DCP) was dissolved in 120mL THF and slowly added dropwise to the THEIC solution for 8h. After that, 14.36g 1,3-bis(3-chloropropyl)-1,1,3,3-tetramethyldisiloxane (BTD) was dissolved in 120mL THF and slowly added dropwise to the above reaction solution, and refluxed at 90°C for 12h. The reaction mixture was cooled, washed, and dried under reduced pressure to obtain CA(DCP)-BTD-CA(DPC).

[0062] Example 4: Flame retardant polyester diol

[0063] Under nitrogen protection, THEIC(DPPC)-TMSOME-THEIC(DPPC), malonic acid (MA) and 1,3-propylene glycol (PDO) with a molar ratio of 0.8:10:9.5 were placed in a flask, and antimony trioxide with a molar amount of 0.14% of malonic acid (MA) was added, and the temperature was raised to 185°C and stirred vigorously. When no water was produced, the esterification reaction was completed. Then the temperature was raised to 230°C, and the polycondensation reaction was carried out at 80Pa for 4 hours. The flame-retardant polyester diol TTT-MA-PDO with a molecular weight of 2000 and end-capped with terminal hydroxyl groups was obtained.

[0064] Example 5: Flame retardant polyester diol

[0065] Under nitrogen protection, TPTEPZ(DPC)-BTD-TPTEPZ(DPC), terephthalic acid (PTA) and ethylene glycol (EG) with a molar ratio of 0.5:10:10 were placed in a flask, and tetrabutyl titanate with a molar amount of 0.14% of terephthalic acid was added, and the temperature was raised to 170°C and stirred vigorously. When no water was produced, the esterification reaction was completed. Then the temperature was raised to 190°C, and the polycondensation reaction was carried out at -0.1MPa for 5 hours. The flame-retardant polyester diol TBT-PTA-EG with a molecular weight of 2600 and end-capped with terminal hydroxyl groups was obtained.

[0066] Example 6: Flame retardant polyester diol

[0067] Under nitrogen protection, CA (DCP) - BTD - CA (DPC), succinic acid (SA) and 1,4-butanediol (BDO) with a molar ratio of 1:10:9.5 were placed in a flask, and a catalyst tetrabutyl titanate with a molar amount of 0.18% of succinic acid (SA) was added, and the temperature was raised to 175 ° C and stirred vigorously. When no water was produced, the esterification reaction was completed. Then the temperature was raised to 215 ° C, and the polycondensation reaction was carried out at -0.1 MPa for 5 hours. The end-hydroxyl-terminated flame-retardant polyester diol CBC-SA-BDO with a molecular weight of 2200 was obtained.

[0068] Example 7: Polyester flame retardant spandex

[0069] (1) Preparation of prepolymer: 2906 g of TTT-MA-PDO with a molecular weight of 2000 and 624 g of 4,4-MDI were reacted at 90° C. for 130 min to obtain a prepolymer having isocyanate groups at both ends. 6524 g of N,N-dimethylacetamide was used to dissolve the prepolymer, and the temperature was cooled to 10° C. to obtain a prepolymer solution.

[0070] (2) Chain extension reaction: 58 g of ethylenediamine and 7 g of diethylamine were added to 1115 g of N,N-dimethylacetamide to obtain a mixed ammonia solution, which was then added to a prepolymer solution cooled to 10° C. while stirring to obtain a high-viscosity stable polymer.

[0071] (3) Preparation of spinning solution: 6 g of anti-yellowing agent, 12 g of matting agent titanium dioxide, 3 g of antioxidant, and 14 g of magnesium stearate were added to the polymer solution to obtain a spinning solution;

[0072] (4) Spinning: The spinning solution is aged at 40°C and then prepared into flame-retardant spandex by means of a dry spinning system through processes such as liquid discharge, spraying, stretching, false twisting, and oiling.

[0073] Example 8: Flame-retardant polyester spandex

[0074] (1) Preparation of prepolymer: 2921 g of TBT-PTA-EG with a molecular weight of 2600 and 524 g of 4,4-MDI were reacted at 90° C. for 130 min to obtain a prepolymer having isocyanate groups at both ends. 6524 g of N,N-dimethylacetamide was used to dissolve the prepolymer, and the temperature was lowered to 10° C. to obtain a prepolymer solution.

[0075] (2) Chain extension reaction: 53 g of ethylenediamine, 17 g of adipic acid dihydrazide, and 6 g of diethylamine were added to 1299 g of N,N-dimethylacetamide to obtain a mixed ammonia solution, which was then added to a prepolymer solution cooled to 10° C. while stirring to obtain a high-viscosity stable polymer;

[0076] (3) Preparation of spinning solution: 6 g of anti-yellowing agent, 12 g of matting agent titanium dioxide, 6 g of antioxidant, and 14 g of magnesium stearate were added to the polymer solution to obtain a spinning solution;

[0077] (4) Spinning: The spinning solution is aged at 40°C and then prepared into flame-retardant spandex by means of a dry spinning system through processes such as liquid discharge, spraying, stretching, false twisting, and oiling.

[0078] Example 9: Polyether flame retardant spandex

[0079] (1) Preparation of prepolymer: 2461 g of polytetramethylene ether glycol with a molecular weight of 1800, 817 g of 4,4-MDI, 18 g of HDI and 227 g of CA(DCP)-BTD-CA(DPC) were reacted at 90° C. for 130 min to obtain a prepolymer having isocyanate groups at both ends, 6411 g of N,N-dimethylacetamide was used to dissolve the prepolymer, and the temperature was cooled to 10° C. to obtain a prepolymer solution;

[0080] (2) Chain extension reaction: 64 g of ethylenediamine and 8 g of diethylamine were added to 1226 g of N,N-dimethylacetamide to obtain a mixed ammonia solution, which was added to the prepolymer solution cooled to 10° C. while stirring to finally obtain a high-viscosity stable polymer;

[0081] (3) Preparation of spinning solution: 12 g of anti-yellowing agent, 17 g of matting agent, 3 g of antioxidant and 14 g of magnesium stearate were added to the polymer solution to obtain spinning solution;

[0082] (4) Spinning: The spinning solution is aged at 40°C and then prepared into flame-retardant spandex by means of a dry spinning system through processes such as liquid discharge, spraying, stretching, false twisting, and oiling.

[0083] Example 10: Polyether flame retardant spandex

[0084] (1) Preparation of prepolymer: 2566 g of polytetramethylene ether glycol with a molecular weight of 2000, 657 g of 4,4-MDI and 242 g of THEIC(DPPC)-TMSOME-THEIC(DPPC) were reacted at 90° C. for 130 min to obtain a prepolymer having isocyanate groups at both ends, 6044 g of N,N-dimethylacetamide was added to dissolve the prepolymer, and the temperature was cooled to 10° C.;

[0085] (2) Chain extension reaction: 61 g of ethylenediamine, 20 g of adipic acid dihydrazide and 7 g of diethylamine were added to 1505 g of N,N-dimethylacetamide to obtain a mixed ammonia solution, which was added to the prepolymer solution cooled to 10° C. while stirring to obtain a high-viscosity stable polymer;

[0086] (3) Preparation of spinning solution: 6 g of anti-yellowing agent, 12 g of matting agent, 3 g of antioxidant, and 14 g of magnesium stearate were added to the polymer solution to obtain a spinning solution;

[0087] (4) Spinning: The spinning solution is aged at 40°C and then prepared into flame-retardant spandex by means of a dry spinning system through processes such as liquid discharge, spraying, stretching, false twisting, and oiling.

[0088] Comparative Example 1:

[0089] (1) Preparation of prepolymer: 2883 g of polytetramethylene ether glycol with a molecular weight of 2000 and 670 g of 4,4-MDI were heated to 90° C. and reacted for 130 min to obtain a prepolymer having isocyanate groups at both ends. 6030 g of N,N-dimethylacetamide was added to dissolve the prepolymer, and the temperature was cooled to 10° C. to obtain a prepolymer solution.

[0090] (2) Chain extension reaction: 62 g of ethylenediamine and 10 g of diethylamine were added to 1393 g of N,N-dimethylacetamide to obtain a mixed ammonia solution, which was then added to a prepolymer solution cooled to 10° C. while stirring to obtain a high-viscosity stable polymer.

[0091] (3) Preparation of spinning solution: 6 g of anti-yellowing agent, 12 g of matting agent titanium dioxide, 5 g of antioxidant, and 14 g of magnesium stearate were added to the polymer solution to obtain a spinning solution;

[0092] (4) Spinning: After the spinning solution is matured at 40°C, spandex is prepared by a dry spinning system through processes such as liquid discharge, spraying, stretching, false twisting, and oiling.

[0093] The performance of the spandex obtained in Example 1 and Comparative Example 1 was tested, and the test results are shown in Table 1.

[0094] Table 1

[0095]

[0096] Note: Tensile test: Fz / T 54010-2014 "Spandex Filament";

[0097] Oxygen index test: After washing 10 times, follow the "(GB / T 5454-1997 Textile combustion performance test oxygen index method".

[0098] It can be seen from Table 1 that the flame retardant of the present invention enables the spandex fiber to have excellent flame retardancy, water washability and good anti-dripping performance. The in-situ polymerization process makes the flame retardant spandex have good spinnability and the flame retardant has little effect on the mechanical properties of the spandex fiber. At the same time, the N / P / Si synergistic effect makes the flame retardant performance of the spandex more prominent.

[0099] The embodiments provided above are not intended to limit the scope of the present invention, and the steps described are not intended to limit the execution order thereof. Those skilled in the art may make obvious improvements to the present invention in combination with existing common knowledge, which also fall within the scope of protection defined by the claims of the present invention.

Claims

1. A flame retardant, characterized in that: The flame retardant has a CN hexacyclic ring or a NP hexacyclic ring, siloxane and a hydroxyl group in its structure; The CN six-membered ring and the NP six-membered ring are one of cyanuric acid ring, triazine ring and phosphazene ring; The hydrogen portions on the CN six-membered ring and the NP six-membered ring are replaced by pentaerythritol phosphate, dimethyl hydroxymethyl phosphite, diphenyl phosphate, dimethyl phosphate, and diphenyl phosphate.

2. The flame retardant according to claim 1, characterized in that The structure is shown in the general formula (1): In the general formula (1), Y represents a C or P element; m and n represent integers of 1 to 3 respectively; R1 is independently H, hydroxymethyl, hydroxyethyl, One of; R2 is independently represented by H, hydroxyl, One or more of; Two adjacent R1s are the same or different; two adjacent R2s are the same or different; At least one of R1 and R2 is a phosphorus-containing substituent.

3. The flame retardant according to claim 1, characterized in that The flame retardant structure is any one of the following structures:

4. A flame retardant polyester diol prepared from the flame retardant according to claim 1, characterized in that: The flame retardant is mixed with dibasic acid and diol, and polycondensation reaction is carried out under the action of a catalyst to prepare flame retardant polyester diol.

5. The flame retardant polyester diol according to claim 4, characterized in that: The dibasic acid is one or more of terephthalic acid, phthalic acid, isophthalic acid, naphthalene dicarboxylic acid, cyclohexanedicarboxylic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, dodecanedioic acid, 2,5-furandicarboxylic acid, and itaconic acid; the dihydric alcohol is one or more of ethylene glycol, 1,2-propylene glycol, 2-methylpropylene glycol, 1,3-propylene glycol, 1,4-butanediol, and neopentyl glycol; the catalyst is one or more of antimony trioxide, antimony acetate, tetrabutyl titanate, ethylene glycol titanium, stannous octoate, and triethylaluminum.

6. The flame retardant polyester diol according to claim 4, characterized in that: The molar ratio of the flame retardant, the dibasic acid and the diol is 0.5-1:10:9.5-10.

7. An application of the flame retardant according to claim 1, characterized in that: Used to prepare polyether flame-retardant spandex.

8. A polyether flame retardant spandex prepared by the flame retardant according to claim 1, characterized in that: The product of the reaction of the flame retardant with polytetramethylene ether glycol and diisocyanate compound is used to prepare spinning solution.

9. An application of the flame retardant polyester diol according to claim 4, characterized in that: Used to prepare polyester flame-retardant spandex.

10. A polyester flame retardant spandex prepared from the flame retardant polyester diol according to claim 4, characterized in that: The reaction product of the flame retardant polyester diol and the diisocyanate compound is used to prepare spinning solution.

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