Preparation method of intumescent flame-retardant coating adhesive and fireproof polyester fabric

Abstract

This invention belongs to the field of polyester fabric technology, and particularly relates to an intumescent flame-retardant coating adhesive and a method for preparing fire-retardant polyester fabrics. The method includes: reacting dicyandiamide with formaldehyde to prepare a dicyandiamide-formaldehyde prepolymer; dispersing glucosamine and ammonium polyphosphate in deionized water and performing anionic-cationic electrostatic association to obtain an APP-GA composite intermediate; reacting the APP-GA composite intermediate with the dicyandiamide-formaldehyde prepolymer at 50-80℃ and pH 6-7 to obtain a crosslinked flame-retardant system; and adding the crosslinked flame-retardant system to a polyvinyl alcohol aqueous solution to obtain an intumescent flame-retardant coating adhesive. This intumescent flame-retardant coating adhesive has high intumescent flame-retardant properties and strong adhesion to fabrics. Fabrics treated with this coating adhesive exhibit excellent flame-retardant and fire-resistant properties and good washability.

Description

Technical Field

[0001] This invention belongs to the field of flame retardant fabric technology, and particularly relates to an intumescent flame retardant coating adhesive and a method for preparing fireproof polyester fabric. Background Technology

[0002] Polyester, as one of the most widely used synthetic fibers, is expanding its applications from ordinary clothing to high-safety fields such as architectural interiors and protective equipment. The market urgently needs fabrics that combine flame retardancy, durability, washability, and a good hand feel. However, ammonium polyphosphate (APP), as the core component of halogen-free flame retardant systems, has inherent defects that lead to the following problems: Firstly, the large number of polar groups on its molecular chain makes it highly hygroscopic, easily agglomerating and migrating in coatings, causing coating deterioration and a decrease in flame retardant performance; secondly, its inorganic particle characteristics have poor compatibility with organic resins, resulting in unstable blended systems and difficulty in forming dense, continuous coatings, leading to stiff fabrics and poor washability.

[0003] To adapt to market demands, modifying ammonium polyphosphate to improve its applicability in flame-retardant fabrics is a hot research topic in the industry. Patent CN104862971A discloses a flame-retardant coating adhesive for textiles, a method for finishing flame-retardant fabrics, and the flame-retardant fabrics thereof. By microencapsulating APP through a double coating of SiO2 / glycidyl ether and introducing it into a solvent-based polyurethane coating, halogen-free flame retardancy and certain wash resistance are achieved. However, the system has no expansion effect and cannot withstand flame impact. Furthermore, the flame-retardant system has poor compatibility with polyurethane and can only withstand 12 mild washes.

[0004] Patent CN118515988B discloses a method for preparing and applying a polyvinyl alcohol-coated ammonium polyphosphate flame retardant. The method involves surface modification of ammonium polyphosphate with polyvinyl alcohol to obtain the polyvinyl alcohol-coated ammonium polyphosphate flame retardant. This flame retardant is then mixed with polyurethane to coat polyester fabric, resulting in a flame-retardant polyester fabric with good flame retardant properties and wash resistance, capable of withstanding 35 washes. However, the coated polyester fabric cannot withstand high-temperature flame impact, and the compatibility and wash resistance of the polyvinyl alcohol-coated ammonium polyphosphate flame retardant with polyurethane need further improvement.

[0005] The existing modification methods mentioned above cannot simultaneously meet the dual requirements of high expansion char formation and resistance to flame impact. When the coating is subjected to strong impact from open flame, the char layer often cracks, peels off, or the expansion ratio is insufficient, which cannot provide stable and reliable long-term protection for polyester fabrics. Summary of the Invention

[0006] In view of the above-mentioned problems in the prior art, the present invention provides an intumescent flame retardant coating adhesive and a method for preparing fireproof polyester fabric. The intumescent flame retardant coating adhesive has high intumescent flame retardant performance and strong adhesion to polyester fabric. The polyester fabric obtained by coating adhesive of the present invention has excellent flame retardant and fireproof performance and good water resistance.

[0007] To achieve the above objectives, the technical solution provided by the present invention is as follows: In a first aspect, this application provides a method for preparing an intumescent flame-retardant coating adhesive, comprising: Dicyandiamide and formaldehyde aqueous solution are mixed and then subjected to hydroxymethylation and polycondensation reactions in sequence to obtain dicyandiamide-formaldehyde prepolymer; APP-GA complex intermediate was obtained by dispersing glucosamine and ammonium polyphosphate in deionized water and performing anionic and cationic electrostatic association. The APP-GA composite intermediate was reacted with dicyandiamide formaldehyde prepolymer at 50-80℃ and pH 6-7 to obtain a dicyandiamide formaldehyde prepolymer-coated modified ammonium polyphosphate crosslinked flame retardant system. The dicyandiamide-formaldehyde prepolymer-coated modified ammonium polyphosphate crosslinked flame retardant system was added to a polyvinyl alcohol aqueous solution to obtain the intumescent flame retardant coating adhesive.

[0008] Optionally, the preparation of the dicyandiamide-formaldehyde prepolymer includes the following steps: Dicyandiamide was added to deionized water and stirred at a constant temperature of 40-50℃ until completely dissolved. Formaldehyde aqueous solution was added dropwise to the dicyandiamide aqueous solution, and the pH was adjusted to maintain at 8.0-8.5 during the process. Then, the hydroxymethylation reaction was carried out by keeping the temperature at 40-50℃ for 20-50 minutes. Then, the temperature is raised to 65-70℃, the pH is adjusted to 6.5-7.0, and the temperature is maintained for 1-2 hours to carry out the polycondensation reaction. The reaction is then cooled to end, and the dicyandiamide-formaldehyde prepolymer is obtained.

[0009] Optionally, the mass ratio of dicyandiamide to formaldehyde is (1.2-2):1.

[0010] Optionally, the preparation of the APP-GA complex intermediate includes the following steps: Ammonium polyphosphate was dispersed in an aqueous solution of glucosamine and stirred to form a suspension.

[0011] Optionally, the mass ratio of ammonium polyphosphate, glucosamine and dicyandiamide formaldehyde prepolymer is (5.5-6):(3-4):(1.5-2.5).

[0012] Optionally, the amount of the dicyandiamide-formaldehyde prepolymer-coated modified ammonium polyphosphate crosslinked flame retardant system added accounts for 5.6-8.7% of the total mass of the intumescent polyester flame retardant coating adhesive; and / or, the mass fraction of the polyvinyl alcohol aqueous solution is 10-15%; and / or, the dicyandiamide-formaldehyde prepolymer-coated modified ammonium polyphosphate crosslinked flame retardant system is added to the polyvinyl alcohol aqueous solution by dropwise addition and stirred at room temperature for 0.5-1 h.

[0013] Secondly, this application also provides an intumescent flame-retardant coating adhesive, obtained by the preparation method described in the first aspect.

[0014] Thirdly, this application also provides a fire-retardant polyester fabric having an intumescent flame-retardant coating adhesive as described in the second aspect attached thereto.

[0015] Fourthly, this application also provides a method for preparing fire-retardant polyester fabric, comprising: applying the intumescent flame-retardant coating adhesive to the fabric, and then drying it at 60-80℃ for 20-30 minutes and baking it at 120-140℃ for 5-10 minutes.

[0016] Optionally, the viscosity of the intumescent flame-retardant coating adhesive is 0.5-1.5 Pa·s; and / or, after drying, the amount of intumescent flame-retardant coating adhesive adhering to the polyester fabric is 70-190 g / m².

[0017] Optionally, the fabric is a polyester fabric, which has been pretreated with alkali.

[0018] Optionally, the alkali pretreatment includes: immersing the polyester fabric in a 15-25 g / L sodium hydroxide aqueous solution, then treating it at 95°C for 40 min, followed by washing it in hot water at 80°C and then washing it in water at room temperature until neutral, and finally drying it at 70°C to constant weight.

[0019] Compared with the prior art, the present invention has at least the following beneficial effects: A stable APP-GA complex intermediate was constructed by electrostatic attraction between the ammonium cation formed by protonation of glucosamine in aqueous phase and the phosphate anion on the surface of ammonium polyphosphate, supplemented by hydrogen bonding. The APP-GA complex intermediate effectively shields the polar groups of ammonium polyphosphate, significantly reduces hygroscopicity, and introduces highly active amino sites for subsequent reactions.

[0020] Dicyandiamide formaldehyde prepolymer is rich in hydroxymethyl active groups and is positively charged overall. On the one hand, it combines with the negatively charged APP-GA complex intermediate through its cationic properties. On the other hand, it forms methylene amine bonds by reacting hydroxymethyl groups with the primary amino groups on the surface of the APP-GA complex intermediate, and reacts with the hydroxyl groups of glucosamine. Through secondary assembly, it can form a dense and strongly interfacially bonded multilayer coating structure.

[0021] The outermost layer of the cross-linked flame retardant system, composed of dicyandiamide-formaldehyde prepolymer, is rich in hydroxymethyl and amino groups, which exhibit excellent compatibility with the numerous hydroxyl groups in the polyvinyl alcohol (PVA) backbone, ensuring uniform dispersion of the cross-linked flame retardant system. Simultaneously, during the baking process, the dicyandiamide-formaldehyde prepolymer undergoes etherification condensation with the hydroxyl groups of PVA through hydroxymethyl groups, while the exposed ammonium polyphosphate undergoes esterification with the hydroxyl groups of PVA through ammonium phosphate, forming a three-dimensional cross-linked network. This ensures a strong bond between the PVA coating layer and the flame retardant system.

[0022] The coating adhesive prepared by the method of this invention exhibits excellent char-forming properties, forming a dense, expanded char layer upon contact with fire, effectively resisting flame impact, and possessing both high expansion ratio and excellent thermal stability. Furthermore, this coating adhesive demonstrates strong adhesion to polyester fabrics, excellent washability, and maintains a pleasant hand feel. Attached Figure Description

[0023] Figure 1 This is a comparison diagram of the expansion thickness of the fire-retardant polyester fabric before and after combustion in Embodiment 1 of the present invention; Figure 2 The image shows the burning state of the fire-retardant polyester fabric at different times during the flame spraying in Embodiment 1 of the present invention. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to the accompanying drawings: Unless otherwise specified, the experimental methods used in the embodiments of this invention are all conventional methods.

[0025] All reagents and materials used in this example can be purchased routinely. The quantitative experiments involved in the examples were all repeated at least three times, and the results were averaged.

[0026] Raw material source: Ammonium polyphosphate: CAS#68333-79-9, chemically pure, Shanghai Yuanye Biotechnology Co., Ltd.; Polyvinyl alcohol: Polyvinyl alcohol 1795 type (PVA, CAS: 9002-89-5; degree of hydrolysis: 92.0%~94.0%); Polyester fabric: 210D filament Oxford cloth, weight 90 g / m 2 C6 waterproof color fabric (155CM from edge to edge), Anhui Kangsitai Textile Technology Co., Ltd., rated as level four water repellency according to ISO 4920-2012.

[0027] Example 1

[0028] An intumescent flame-retardant coating adhesive, the preparation method of which is as follows: 2.0 g of dicyandiamide was added to 30 mL of deionized water and stirred at 45 °C until completely dissolved. 3.9 g of 37 wt% formaldehyde aqueous solution was added dropwise to the dicyandiamide aqueous solution, maintaining the pH at 8.2 during the process. The solution was then kept at 45 °C for 35 min to carry out hydroxymethylation. The temperature was then raised to 67 °C, the pH was adjusted to 6.7, and the solution was kept at this temperature for 1.2 h to carry out polycondensation. The reaction was then stopped by cooling to obtain the dicyandiamide-formaldehyde prepolymer (DICY-F), which was then set aside for later use. Ammonium polyphosphate (APP, 6 g) was dispersed in 50 mL of deionized water and stirred at 2000 rpm for 20 min to form a homogeneous suspension. Glucosamine (GA, 4 g) was then added, and stirring continued at room temperature for another 20 min until completely dissolved. The mixture was then sonicated at 200 W for 15 min to obtain a stable APP-GA complex intermediate for later use.

[0029] First, prepare a 100g 10wt% PVA hot aqueous solution (solution at 90℃, the same applies to subsequent examples), cool it to room temperature for later use. Heat the above APP-GA composite intermediate to 65℃, then slowly add dicyandiamide-formaldehyde prepolymer solution, and adjust the pH of the system to 6.5 with dilute hydrochloric acid / NaOH. React at 65℃ for 1 h to obtain a dicyandiamide-formaldehyde prepolymer-coated modified ammonium polyphosphate crosslinked flame retardant system. Then, slowly add the crosslinked flame retardant system to a 10wt% PVA aqueous solution and stir at room temperature for 0.5 h (where the mass fraction of the crosslinked flame retardant system is 6.9%, APP:GA:DICY-F=6:4:2) to obtain an intumescent polyester flame retardant coating adhesive.

[0030] Fire-retardant polyester fabric is obtained by the following method: Pretreatment of polyester fabrics: First, prepare a 20 g / L NaOH aqueous solution and immerse the polyester fabric in the treatment solution at a liquor ratio of 1:30. Then, place the system in a constant temperature water bath and heat it to 95°C and maintain the constant temperature for 40 min. Then, wash it twice with 80°C hot water and wash it with room temperature water until neutral to completely remove residual alkali and hydrolysis products. Finally, dry it in a 70°C oven until constant weight and set aside for later use.

[0031] The viscosity of the intumescent flame-retardant coating adhesive was adjusted to 0.5 Pa·s using deionized water. The coating adhesive was then uniformly applied to the pretreated polyester fabric using a doctor blade coating method. The fabric was then pre-baked at 80°C for 20 min to remove free moisture, and then baked at 140°C for 5 min to further cross-link and form a film inside the coating. After cooling, the fire-retardant polyester fabric was obtained. In this embodiment, the amount of coating on the fabric after drying was 160.7 g / m².

[0032] Example 2

[0033] An intumescent flame-retardant coating adhesive, the preparation method of which is as follows: 1.5 g of dicyandiamide was added to 30 mL of deionized water and stirred at 40 °C until completely dissolved. 2.9 g of a 37 wt% formaldehyde aqueous solution was added dropwise to the dicyandiamide aqueous solution, maintaining the pH at 8.0 during the process. The solution was then kept at 40 °C for 50 min to carry out a hydroxymethylation reaction. The temperature was then raised to 65 °C, the pH was adjusted to 6.5, and the solution was kept at this temperature for 1.5 h to carry out a polycondensation reaction. The reaction was then cooled to terminate the reaction, yielding the dicyandiamide-formaldehyde prepolymer for later use. Ammonium polyphosphate (APP, 5 g) was dispersed in 45 mL of deionized water and stirred at 3000 rpm for 10 min to form a homogeneous suspension. Glucosamine (GA, 3 g) was then added, and stirring continued at room temperature for 10 min until completely dissolved. The mixture was then sonicated at 200 W for 15 min to obtain a stable APP-GA complex intermediate for later use.

[0034] First, prepare a 12wt% PVA hot aqueous solution with a total mass of 100g and cool it to 50℃ for later use. Then, heat the above APP-GA composite intermediate to 60℃, and then slowly add the dicyandiamide-formaldehyde prepolymer solution. Adjust the pH of the system to 6.8 with dilute hydrochloric acid / NaOH and react for 1.5 h to obtain a dicyandiamide-formaldehyde prepolymer-coated and modified ammonium polyphosphate crosslinked flame retardant system. Then, slowly add the crosslinked flame retardant system to the 12wt% PVA aqueous solution and stir at room temperature for 0.6 h (where the mass fraction of the crosslinked flame retardant system is 5.6%, and APP:GA:DICY-F=5:3:1.5) to obtain an intumescent polyester flame retardant coating adhesive.

[0035] Fire-retardant polyester fabric is obtained by the following method: Pretreatment of polyester fabrics: First, prepare a 20 g / L NaOH aqueous solution and immerse the polyester fabric in the treatment solution at a liquor ratio of 1:30. Then, place the system in a constant temperature water bath and heat it to 95°C and maintain the constant temperature for 40 min. Then, wash it twice with 80°C hot water and wash it with room temperature water until neutral to completely remove residual alkali and hydrolysis products. Finally, dry it in a 70°C oven until constant weight and set aside for later use.

[0036] The viscosity of the intumescent flame-retardant coating adhesive was adjusted to 1 Pa·s. The coating adhesive was then uniformly coated onto the pretreated polyester fabric using a doctor blade coating method. The fabric was then pre-baked at 70°C for 25 min to remove free moisture, and then baked at 120°C for 10 min to further cross-link and form a film inside the coating. After cooling, the fire-retardant polyester fabric was obtained. In this embodiment, the amount of coating adhering to the fabric after drying was 128.3 g / m².

[0037] Example 3

[0038] An intumescent flame-retardant coating adhesive, the preparation method of which is as follows: 1.8 g of dicyandiamide was added to 30 mL of deionized water and stirred at 50 °C until completely dissolved. 2.9 g of 37 wt% formaldehyde aqueous solution was added dropwise to the dicyandiamide aqueous solution, and the pH was adjusted to maintain at 8.5 during the process. Then, the solution was kept at 50 °C for 20 min to carry out the hydroxymethylation reaction. The temperature was then raised to 70 °C, the pH was adjusted to 7, and the solution was kept at 7 h to carry out the polycondensation reaction. The reaction was then cooled to end, and the dicyandiamide-formaldehyde prepolymer was obtained for later use. Ammonium polyphosphate (APP, 6 g) was dispersed in 50 mL of deionized water and stirred at 2500 rpm for 15 min to form a homogeneous suspension. Glucosamine (GA, 3.5 g) was then added, and stirring continued at room temperature for another 15 min until completely dissolved. To further promote the uniform adsorption and electrostatic self-assembly of GA on the APP surface, the system was placed in an ultrasonic cleaner and sonicated at 200 W for 20 min to obtain a stable APP-GA composite intermediate for later use.

[0039] First, prepare a 15wt% PVA hot aqueous solution with a total mass of 100 g and cool it to room temperature for later use. Then, heat the above APP-GA composite intermediate to 60℃, and then slowly add the dicyandiamide formaldehyde prepolymer solution. Adjust the pH of the system to 6.3 with dilute hydrochloric acid / NaOH and react at 60℃ for 1.5 h to obtain a crosslinked flame retardant system. Then, slowly add the crosslinked flame retardant system to the 15wt% PVA aqueous solution and stir at room temperature for 2 h (where the mass fraction of the crosslinked flame retardant system is 8.7%, and APP:GA:DICY-F=6:3.5:1.8) to obtain an intumescent flame retardant coating adhesive.

[0040] Fire-retardant polyester fabric is obtained by the following method: Pretreatment of polyester fabrics: First, prepare a 20 g / L NaOH aqueous solution and immerse the polyester fabric in the treatment solution at a liquor ratio of 1:30. Then, place the system in a constant temperature water bath and heat it to 95°C and maintain the constant temperature for 40 min. Then, wash it twice with 80°C hot water and wash it with room temperature water until neutral to completely remove residual alkali and hydrolysis products. Finally, dry it in a 70°C oven until constant weight and set aside for later use.

[0041] The viscosity of the intumescent flame-retardant coating adhesive was adjusted to 1.5 Pa·s. The coating adhesive was then uniformly applied to the pretreated polyester fabric using a scraper. The fabric was then pre-baked at 75°C for 20 min to remove free moisture, and then baked at 130°C for 8 min to further cross-link and form a film inside the coating. After cooling, the fire-retardant polyester fabric was obtained. In this embodiment, the amount of coating on the fabric after drying was 152.5 g / m².

[0042] Example 4

[0043] The difference between this embodiment and Embodiment 1 is that the amount of coating adhering to the fabric after drying in this embodiment is 158.1 g / m².

[0044] Example 5

[0045] The difference between this embodiment and Embodiment 1 is that the amount of coating adhering to the fabric after drying in this embodiment is 180g / m².

[0046] Comparative Example 1 The difference between this comparative example and Example 1 is that no intumescent polyester flame-retardant coating was applied to the pretreated polyester fabric, and the pretreated polyester fabric was tested directly.

[0047] Combustion test results: The polyester fabric burned through after being continuously sprayed with a 600℃ high-temperature blowtorch for 2 seconds. It exhibited molten dripping when burned vertically and ignited the degreased cotton. The damaged length was 30.0 cm, and the LOI was 20.5%.

[0048] Comparative Example 2 First, prepare a 10wt% PVA aqueous solution with a total mass of 100g and cool it to 55℃ for later use. Then, disperse ammonium polyphosphate (APP, 6g) in 50 mL of deionized water. Add the dissolved ammonium polyphosphate solution to the 10wt% PVA aqueous solution and mix evenly to obtain the flame retardant coating adhesive. The viscosity of the flame-retardant coating adhesive was adjusted to 50 mPa·s, and the coating adhesive was uniformly coated onto the pretreated polyester fabric using a doctor blade coating method. Then, it was pre-baked at 80℃ for 20 min to remove free moisture, and then baked at 140℃ for 5 min to further cross-link and form a film inside the coating. After cooling, the fire-retardant polyester fabric was obtained. In this embodiment, the adhesion amount of the dried coating on the fabric was 160.7 g / m².

[0049] Combustion test results: The fire-retardant polyester fabric was burned through after being continuously sprayed with a 600℃ high-temperature blowtorch for 5 seconds. There was no dripping phenomenon when burning vertically. The damaged length was 10.0cm, the LOI was 28.6%, and it could withstand 5 washes.

[0050] Comparative Example 3 First, prepare a 100g (w / w) 10wt% PVA aqueous solution and cool it to 55°C for later use. Then, disperse ammonium polyphosphate (APP, 6g) in 50 mL of deionized water, followed by the addition of glucosamine (GA, 4g). Continue stirring at room temperature for 20 min until completely dissolved, and then sonicate (using the same method as in Example 1) to obtain the APP-GA composite intermediate. Add the APP-GA composite intermediate to the 10wt% PVA aqueous solution and mix thoroughly to obtain the flame-retardant coating adhesive.

[0051] The fire-retardant polyester fabric was prepared using a flame-retardant coating adhesive, following the same steps as in Example 1.

[0052] Combustion test results: The fire-retardant polyester fabric was burned through after being continuously sprayed with a 600℃ high-temperature blowtorch for 10 seconds. There was no dripping phenomenon when burning vertically. The damaged length was 9.0cm, the LOI was 30.2%, and it could withstand 15 washes.

[0053] Comparative Example 4 The difference between this comparative example and the embodiment is that: no formaldehyde aqueous solution was added, and dicyandiamide was directly dissolved and added to the APP-GA composite intermediate to obtain a crosslinked flame retardant system; then, following the same steps as in Example 1, the crosslinked flame retardant system was dripped into the PVA aqueous solution to prepare an intumescent flame retardant coating adhesive and a fireproof polyester fabric.

[0054] In this comparative example, ammonium polyphosphate could not form a coating. The fire-retardant polyester fabric was burned through after being continuously sprayed with a 600°C high-temperature blowtorch for 20 seconds. There was no dripping phenomenon when burning vertically. The damaged length was 8.4cm, the LOI was 31.6%, and it could withstand 25 washes.

[0055] Test method: Vertical burning test: The flame retardant properties of polyester fabrics were evaluated according to GB / T5455-2014 "Determination of vertical damage length, smoldering and afterflame time of textiles". The fabric was cut into pieces with dimensions of 15×8cm. 2 For the sample, the flame height was 4cm, the ignition time was 12s, and important indicators such as the damage length, smoldering time and afterburning time were recorded.

[0056] Limiting oxygen test: The limiting oxygen index of polyester fabrics before and after finishing was tested using an FTT0080 oxygen indexer, according to GB / T5454-2008 "Test for flammability of textiles - Oxygen index method". The fabric size was 8×6cm. 2 .

[0057] Wash fastness test: The flame retardant durability of flame-retardant polyester fabrics was tested according to AATCC™ 61-2013e (2020) "Test method for color fastness to washing: Accelerated method" (2A). The soap flake concentration was 1.5 g / L, the washing temperature was 49℃, the washing time was 45 min, and the liquor ratio was 1:50. After washing, the soap residue on the surface of the flame-retardant polyester fabric was rinsed off with deionized water, and then dried in an electric hot air drying oven at 80℃ for 20 min. One accelerated wash was equivalent to five commercial washes.

[0058] Expansion height test: Place the expanded sample horizontally in the test area and use a thickness gauge to measure the thickness, recording the value. Expansion ratio = Thickness of fire-retardant polyester fabric after burning / Thickness of fire-retardant polyester fabric before burning.

[0059] Fire resistance test: Cut a 12cm×8cm piece of fire-resistant polyester fabric and fix it to an iron frame on both sides. Use a 600℃ high-temperature torch to spray fire vertically and continuously until the fabric is burned through. Record the fire resistance time (s).

[0060] The performance test results of the fire-retardant polyester fabrics obtained in Examples 1-5 of this invention are shown in Table 1.

[0061] Table 1 Performance Tests of Fire-Resistant Polyester Fabrics 1 160.7 35.6 5.4 none 0 70 42.2 50 2 128.3 32.7 8 none 0 35 16.3 30 3 152.5 33.3 7.5 none 0 42 20.5 30 4 158.1 34.2 6.2 none 0 55 30.7 35 5 180 39.1 2.6 none 0 91 55.6 60 The fire-resistant polyester fabric of this invention, under different weight gain conditions, can withstand fire for 35-91 seconds, with an expansion ratio of 16.3-42.2 times, an LOI of 32.7%-39.1%, a damaged length reduced to 8-2.6 cm, and can withstand 30-60 washes.

[0062] Figure 1 and Figure 2 The fire-retardant polyester fabric prepared for Embodiment 1 of the present invention was continuously sprayed with a 600°C high-temperature flame gun for 70 seconds. The comparison of the expansion thickness before and after combustion and the combustion state diagram at different spraying times show that the fire-retardant polyester fabric obtained by the present invention has high expansion flame-retardant properties.

[0063] In this invention, during the initial heating stage, the ammonium polyphosphate, acting as an acid source, undergoes a deamination reaction to generate polyphosphoric acid, a strong protic acid. This acidic substance rapidly catalyzes the hydroxyl-rich structures in the polyvinyl alcohol backbone and glucosamine residues, acting as a carbon source, initiating dehydration, esterification, and crosslinking reactions. This results in the in-situ formation of a viscoelastic phospholipid gel on the particle surface, bridging the network with POC bonds. Simultaneously, the dicyandiamide-formaldehyde low condensate and the methyleneamine bond (-NH-CH2-NH-) formed between the dicyandiamide-formaldehyde and GA undergo chain scission and decomposition at high temperatures, releasing inert gases such as ammonia, nitrogen, and water vapor. Because DICY-F tightly bonds the APP-GA core-shell structure to the PVA matrix via covalent bonds, the gas release is confined within the increased viscosity of the viscoelastic body, making it difficult for the gas to escape. This causes the semi-molten gel to in-situ inflate, forming porous bubbles. As the temperature rises further, the cross-linked network undergoes aromatization, and excess phosphate species condense into a high-temperature resistant polyphosphate glass phase. This glass phase spreads along the bubble walls and fills microcracks, eventually solidifying to form a dense, expanded char layer. This char layer, with its high expansion ratio and low permeability, effectively blocks heat transfer to the polyester substrate and isolates oxygen. Simultaneously, by physically covering and restricting the flow of the polymer melt, it significantly inhibits droplet formation and blocks flame spread, giving the polyester fabric excellent flame-retardant properties.

Claims

1. A method for preparing an intumescent flame-retardant coating adhesive, characterized in that, include: Dicyandiamide and formaldehyde aqueous solution are mixed and subjected to hydroxymethylation and polycondensation reactions to obtain dicyandiamide-formaldehyde prepolymer; APP-GA complex intermediate was obtained by dispersing glucosamine and ammonium polyphosphate in deionized water and performing anionic and cationic electrostatic association. The APP-GA composite intermediate was reacted with dicyandiamide formaldehyde prepolymer at 50-80℃ and pH 6-7 to obtain a dicyandiamide formaldehyde prepolymer-coated modified ammonium polyphosphate crosslinked flame retardant system. The dicyandiamide-formaldehyde prepolymer-coated modified ammonium polyphosphate crosslinked flame retardant system was added to a polyvinyl alcohol aqueous solution to obtain the intumescent polyester flame retardant coating adhesive.

2. The method for preparing the intumescent flame-retardant coating adhesive according to claim 1, characterized in that, The preparation of the dicyandiamide-formaldehyde prepolymer includes the following steps: Dicyandiamide was added to deionized water and stirred at a constant temperature of 40-50℃ until completely dissolved. Formaldehyde aqueous solution was added dropwise to the dicyandiamide aqueous solution, and the pH was adjusted to maintain at 8.0-8.5 during the process. Then, the hydroxymethylation reaction was carried out by keeping the temperature at 40-50℃ for 20-50 minutes. Then, the temperature is raised to 65-70℃, the pH is adjusted to 6.5-7.0, and the temperature is maintained for 1-2 hours to carry out the polycondensation reaction. The reaction is then cooled to end, and the dicyandiamide-formaldehyde prepolymer is obtained.

3. The method for preparing the intumescent flame-retardant coating adhesive according to claim 1, characterized in that, The mass ratio of dicyandiamide to formaldehyde is (1.2-2):

1.

4. The method for preparing the intumescent flame-retardant coating adhesive according to claim 1, characterized in that, The preparation of the APP-GA complex intermediate includes the following steps: Ammonium polyphosphate was dispersed in an aqueous solution of glucosamine and stirred to form a suspension.

5. The method for preparing the intumescent flame-retardant coating adhesive according to claim 1, characterized in that, The mass ratio of ammonium polyphosphate, glucosamine and dicyandiamide formaldehyde prepolymer is (5.5-6):(3-4):(1.5-2.5).

6. The method for preparing the intumescent flame-retardant coating adhesive according to claim 1, characterized in that, The amount of the dicyandiamide-formaldehyde prepolymer-coated modified ammonium polyphosphate crosslinked flame retardant system added accounts for 5.6-8.7% of the total mass of the intumescent flame retardant coating adhesive; and / or, the mass fraction of the polyvinyl alcohol aqueous solution is 10-15%; and / or, the dicyandiamide-formaldehyde prepolymer-coated modified ammonium polyphosphate crosslinked flame retardant system is added to the polyvinyl alcohol aqueous solution by dropwise addition and stirred at room temperature for 0.5-1 h.

7. An intumescent flame-retardant coating adhesive, characterized in that, It is obtained by the preparation method according to any one of claims 1-6.

8. A fire-retardant polyester fabric, characterized in that, It is coated with the intumescent flame-retardant coating adhesive as described in claim 7.

9. A method for preparing the fire-retardant polyester fabric as described in claim 8, characterized in that: include: The intumescent flame-retardant coating adhesive is applied to the fabric by scraping, and then dried at 60-80℃ for 20-30 minutes and baked at 120-140℃ for 5-10 minutes.

10. The polyester fabric according to claim 9, characterized in that, The viscosity of the intumescent flame-retardant coating adhesive is 0.5-1.5 Pa·s; and / or, after drying, the adhesion amount of the intumescent flame-retardant coating adhesive on the fabric is 70-190 g / m²; and / or, the fabric is a polyester fabric, which has been pretreated with alkali.

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