Preparation method and application of flame-retardant composite material for preventing kettle belt of Pack

Abstract

The invention relates to a preparation method and application of a flame-retardant composite material for a Pack bag anti-kettle belt, and belongs to the technical field of composite materials. The flame-retardant composite material is prepared by attaching the flame-retardant polyurethane coating on the surface of the nylon base cloth, and a compatibilizing flame retardant with an amino group, a phosphate structure and a quaternary ammonium salt structure is used in the preparation of the nylon base cloth and the flame-retardant polyurethane coating. The flame retardant has good compatibility with the nylon base cloth and the flame-retardant polyurethane coating, and can improve the adhesive force of the flame-retardant polyurethane coating on the surface of the nylon base cloth, so that the flame-retardant composite material can have more lasting waterproof and flame-retardant effects, and can better adapt to the use background that the pack anti-kettle belt is subjected to friction stretching outdoors for a long time.

Description

Technical Field

[0001] This invention belongs to the field of composite material technology, specifically relating to a method for preparing a flame-retardant composite material for a bottle cap strap in a pack and its application. Background Technology

[0002] In the field of outdoor gear, bottle cap straps in packs, as a key load-bearing component, need to possess high strength, abrasion resistance, and reliable flame retardancy. Nylon fiber, due to its excellent mechanical properties, abrasion resistance, and chemical resistance, is an ideal substrate for manufacturing such fabrics. However, nylon itself is a flammable material with a low limiting oxygen index, and it easily melts and drips under flame, which greatly limits its application in situations with strict flame retardancy requirements.

[0003] To improve flame retardancy, the conventional method is to blend and add flame retardants. Among them, phosphorus-based flame retardants, especially phosphate esters, have attracted much attention because they can exert flame retardant effects in both the gas and condensed phases. However, traditional small-molecule phosphate ester flame retardants have poor compatibility with the nylon matrix and are prone to migration and precipitation during processing and use. This not only leads to a decline in flame retardant performance over time but also severely damages the crystalline structure and intermolecular forces of the nylon matrix, resulting in a significant decrease in key mechanical properties such as tensile strength and toughness, failing to meet the long-term load-bearing and friction requirements of the water bottle strap. On the other hand, to impart additional functions such as waterproofing and abrasion resistance to the fabric coating, it is often necessary to coat its surface with functional coatings such as polyurethane. However, the addition of flame retardants often further deteriorates the interfacial adhesion between the nylon base fabric and the functional coating, resulting in insufficient coating adhesion. Under dynamic bending and friction, the coating is easily peeled off, causing the composite material to lose its overall protective performance.

[0004] To address the above-mentioned technical deficiencies, this invention provides a method for preparing a flame-retardant composite material for use in bottle cap straps in packs and its application. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing a flame-retardant composite material for a pack bottle strap and its application, in order to solve the problems mentioned in the background art.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A method for preparing a flame-retardant composite material for a bottle cap strap in a pack includes the following steps:

[0008] The first step involves reacting 2-chloroethyl dichlorophosphoric acid with pentaerythritol to obtain a flame retardant;

[0009] The reaction process is as follows: 2-chloroethyl dichlorophosphoric acid, pentaerythritol, triethylamine and isopropanol are mixed in a reaction vessel and reacted at a temperature of 50-80℃ for 2-3 hours. After the reaction is completed, the solvent is removed by rotary evaporation of the reaction solution, and the remaining solid is washed with deionized water and dried to obtain the flame retardant.

[0010] The second step is to react the flame retardant with 2,3-diaminopyridine to obtain the compatibilizing flame retardant;

[0011] The reaction process is as follows: the flame retardant, 2,3-diaminopyridine, and isopropanol are mixed in a reaction vessel and reacted at a temperature of 60-90℃ for 6-12 hours. After the reaction is completed, the solvent is removed by rotary evaporation of the reaction solution, and the remaining solid is recrystallized with anhydrous ethanol to obtain the compatibilized flame retardant.

[0012] The third step involves polymerizing the raw materials polytetrahydrofuran ether diol, polyisocyanate, dibutyltin dilaurate, and compatibilizer / flame retardant to obtain flame retardant polyurethane.

[0013] The reaction process is as follows: polytetrahydrofuran ether diol, polyisocyanate, dibutyltin dilaurate, and isopropanol are mixed and reacted at a temperature of 50-70℃ for 1-3 hours. Then, a compatibilizing flame retardant is added to the system and the reaction is continued at a temperature of 50-70℃ for 40-60 minutes. After the reaction is completed, the isopropanol is removed by rotary evaporation of the reaction solution to obtain flame-retardant polyurethane.

[0014] Step 4: Mix nylon resin, compatibilizer, flame retardant, and antioxidant, and then melt extrude and spin to obtain flame retardant nylon fiber. The flame retardant nylon fiber is then woven to obtain nylon base fabric.

[0015] Step 5: After swelling the nylon base fabric, remove the nylon base fabric and coat the surface of the swollen nylon base fabric with flame-retardant polyurethane emulsion, and then cure it to obtain a flame-retardant composite material.

[0016] Furthermore, the temperature conditions for the melt extrusion are 230–260°C.

[0017] Furthermore, the swelling conditions are as follows: using a 50-70% volume fraction of isopropanol aqueous solution as a solvent, immersing the nylon base fabric in the solvent, and swelling at a temperature of 40-60°C for 1-5 minutes.

[0018] Furthermore, the curing conditions are as follows: curing at a temperature of 80–120°C for 1–2 hours.

[0019] Furthermore, the mass ratio of the nylon resin, compatibilizer, flame retardant, and antioxidant used is 100:18-25:0.3-0.8.

[0020] Furthermore, the mass ratio of polytetrahydrofuran ether diol, polyisocyanate, dibutyltin dilaurate, and compatibilizer / flame retardant used is 100:40-60:0.5-2:15-20.

[0021] Furthermore, the polyisocyanate is at least one of diphenylmethane diisocyanate and isophorone diisocyanate.

[0022] Furthermore, the flame-retardant polyurethane emulsion comprises the following raw materials in parts by weight: 100 parts flame-retardant polyurethane, 8-12 parts isopropanol, and 0.5-2 parts thickener.

[0023] Furthermore, the coating amount of the flame-retardant polyurethane emulsion is 15-25 g / m². 2 .

[0024] The present invention also provides applications of the flame-retardant composite material prepared by the above preparation method.

[0025] Application of a flame-retardant composite material prepared by any of the steps described above in the field of bottle cap straps for packs.

[0026] The beneficial effects of this invention are:

[0027] 1) This invention prepares a compatibilizing flame retardant with amino, phosphate ester and quaternary ammonium salt structures in its structure. The quaternary ammonium salt can catalyze the decomposition of phosphate ester at high temperature to reduce the corresponding flame temperature, while the phosphate ester, amino and quaternary ammonium salt structures can produce an effective "gas phase-condensed phase" synergistic flame retardant effect, effectively improving the flame retardant effect of flame retardant composite materials.

[0028] 2) The compatibilizer and flame retardant of the present invention contain both quaternary ammonium salt structure and amino structure. The amino structure and quaternary ammonium salt structure can generate ion-dipole interaction with the amide group in the nylon base fabric, improve the compatibility between the phosphate flame retardant and the nylon base fabric, alleviate the adverse effects on the mechanical properties of the nylon base fabric caused by the compatibility defects between the flame retardant and the nylon matrix, and improve the mechanical properties of the nylon base fabric. Moreover, after the nylon base fabric is swollen, the amino group in the compatibilizer and flame retardant in the nylon matrix is ​​activated, thereby reacting with the residual isocyanate group in the flame retardant polyurethane emulsion, significantly improving the adhesion of the flame retardant polyurethane coating on the surface of the nylon base fabric. The improved adhesion can greatly reduce the possibility of the flame retardant polyurethane coating falling off after long-term use, so that the flame retardant composite material can have a more durable waterproof and flame retardant effect, and better adapt to the background of long-term outdoor use of packs and bottle straps subjected to friction and stretching. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1

[0031] A method for preparing a flame-retardant composite material for a bottle cap strap in a pack includes the following steps:

[0032] Step 1: Mix 75 parts by mass of 2-chloroethyl dichlorophosphoric acid, 25 parts by mass of pentaerythritol, 70 parts by mass of triethylamine and 450 parts by mass of isopropanol in a reaction vessel and react at 50°C for 3 hours. After the reaction is complete, remove the solvent by rotary evaporation of the reaction solution, and wash the remaining solid with deionized water and dry it to obtain the flame retardant.

[0033] The second step involves mixing 60 parts by mass of flame retardant, 36 parts by mass of 2,3-diaminopyridine, and 280 parts by mass of isopropanol in a reaction vessel and reacting at 60°C for 12 hours. After the reaction is complete, the solvent is removed by rotary evaporation of the reaction solution, and the remaining solid is recrystallized with anhydrous ethanol to obtain the compatibilizing flame retardant.

[0034] Step 3: According to the mass fraction, mix 100 parts of polytetrahydrofuran ether diol 1800, 40 parts of diphenylmethane diisocyanate, 0.5 parts of dibutyltin dilaurate, and 420 parts of isopropanol and react at 50°C for 3 hours. Then add 15 parts of compatibilizer flame retardant to the system and continue to react at 50°C for 60 minutes. After the reaction is completed, remove the isopropanol by rotary evaporation to obtain flame-retardant polyurethane.

[0035] Step 4: By mass, 100 parts of nylon 6 resin, 18 parts of compatibilizer and flame retardant, and 0.3 parts of antioxidant 1010 are mixed and melt-extruded at a temperature of 230°C. The mixture is then spun to obtain flame-retardant nylon fiber, which is then woven to obtain nylon base fabric.

[0036] Step 5: Using a 50% (v / v) isopropanol aqueous solution as a solvent, immerse the nylon base fabric in the solvent and allow it to swell for 5 minutes at 40°C. Then remove the nylon base fabric and apply a coating at a rate of 15 g / m². 2 The standard involves coating the swollen nylon base fabric with a flame-retardant polyurethane emulsion, followed by curing at 80°C for 2 hours to obtain a flame-retardant composite material.

[0037] In this embodiment, the flame-retardant polyurethane emulsion is obtained by mixing the following raw materials: 100 parts flame-retardant polyurethane, 8 parts isopropanol, and 0.5 parts thickener, wherein the thickener is hydroxyethyl cellulose.

[0038] Application of a flame-retardant composite material prepared by the above steps in the field of bottle cap straps.

[0039] Example 2

[0040] A method for preparing a flame-retardant composite material for a bottle cap strap in a pack includes the following steps:

[0041] Step 1: Mix 75 parts by mass of 2-chloroethyl dichlorophosphoric acid, 25 parts by mass of pentaerythritol, 70 parts by mass of triethylamine and 450 parts by mass of isopropanol in a reaction vessel and react at 50°C for 3 hours. After the reaction is complete, remove the solvent by rotary evaporation of the reaction solution, and wash the remaining solid with deionized water and dry it to obtain the flame retardant.

[0042] The second step involves mixing 60 parts by mass of flame retardant, 36 parts by mass of 2,3-diaminopyridine, and 280 parts by mass of isopropanol in a reaction vessel and reacting at 60°C for 12 hours. After the reaction is complete, the solvent is removed by rotary evaporation of the reaction solution, and the remaining solid is recrystallized with anhydrous ethanol to obtain the compatibilizing flame retardant.

[0043] Step 3: By mass, mix 100 parts of polytetrahydrofuran ether diol 1800, 40 parts of isophorone diisocyanate, 0.5 parts of dibutyltin dilaurate, and 420 parts of isopropanol and react at 50°C for 3 hours. Then, add 15 parts of compatibilizer and flame retardant to the system and continue the reaction at 50°C for 60 minutes. After the reaction is completed, remove the isopropanol by rotary evaporation to obtain flame-retardant polyurethane.

[0044] Step 4: By mass, 100 parts of nylon 6 resin, 18 parts of compatibilizer and flame retardant, and 0.3 parts of antioxidant 1010 are mixed and melt-extruded at a temperature of 230°C. The mixture is then spun to obtain flame-retardant nylon fiber, which is then woven to obtain nylon base fabric.

[0045] Step 5: Using a 50% (v / v) isopropanol aqueous solution as a solvent, immerse the nylon base fabric in the solvent and allow it to swell for 5 minutes at 40°C. Then remove the nylon base fabric and apply a coating at a rate of 15 g / m². 2 The standard involves coating the swollen nylon base fabric with a flame-retardant polyurethane emulsion, followed by curing at 80°C for 2 hours to obtain a flame-retardant composite material.

[0046] In this embodiment, the flame-retardant polyurethane emulsion is obtained by mixing the following raw materials: 100 parts flame-retardant polyurethane, 8 parts isopropanol, and 0.5 parts thickener, wherein the thickener is hydroxyethyl cellulose.

[0047] Application of a flame-retardant composite material prepared by the above steps in the field of bottle cap straps.

[0048] Example 3

[0049] A method for preparing a flame-retardant composite material for a bottle cap strap in a pack includes the following steps:

[0050] Step 1: Mix 75 parts by mass of 2-chloroethyl dichlorophosphoric acid, 25 parts by mass of pentaerythritol, 70 parts by mass of triethylamine and 450 parts by mass of isopropanol in a reaction vessel and react at 65°C for 2.5 hours. After the reaction is complete, remove the solvent by rotary evaporation of the reaction solution, and wash the remaining solid with deionized water and dry it to obtain the flame retardant.

[0051] The second step involves mixing 60 parts by mass of flame retardant, 36 parts by mass of 2,3-diaminopyridine, and 280 parts by mass of isopropanol in a reaction vessel and reacting at 75°C for 9 hours. After the reaction is complete, the solvent is removed by rotary evaporation of the reaction solution, and the remaining solid is recrystallized with anhydrous ethanol to obtain the compatibilizing flame retardant.

[0052] Step 3: By mass, 100 parts of polytetrahydrofuran ether diol 1400, 50 parts of diphenylmethane diisocyanate, 1.25 parts of dibutyltin dilaurate, and 450 parts of isopropanol are mixed and reacted at 60°C for 2 hours. Then, 17.5 parts of compatibilizer and flame retardant are added to the system and the reaction is continued at 60°C for 50 minutes. After the reaction is completed, the isopropanol is removed by rotary evaporation of the reaction solution to obtain flame-retardant polyurethane.

[0053] Step 4: By weight, 100 parts of nylon 66 resin, 21.5 parts of compatibilizer and flame retardant and 0.55 parts of antioxidant 1035 are mixed and melt-extruded at a temperature of 245℃ and then spun to obtain flame retardant nylon fiber. The flame retardant nylon fiber is then woven to obtain nylon base fabric.

[0054] Step 5: Using a 60% (v / v) isopropanol aqueous solution as a solvent, immerse the nylon base fabric in the solvent and allow it to swell for 3 minutes at 50°C. Then remove the nylon base fabric and apply a coating at a rate of 20 g / m². 2 The standard involves coating the swollen nylon base fabric with a flame-retardant polyurethane emulsion, followed by curing at 100°C for 1.5 hours to obtain a flame-retardant composite material.

[0055] In this embodiment, the flame-retardant polyurethane emulsion is obtained by mixing the following raw materials: 100 parts flame-retardant polyurethane, 10 parts isopropanol, and 1.25 parts thickener, wherein the thickener used is thickener RM-8W.

[0056] Application of a flame-retardant composite material prepared by the above steps in the field of bottle cap straps.

[0057] Example 4

[0058] A method for preparing a flame-retardant composite material for a bottle cap strap in a pack includes the following steps:

[0059] Step 1: Mix 75 parts by mass of 2-chloroethyl dichlorophosphoric acid, 25 parts by mass of pentaerythritol, 70 parts by mass of triethylamine and 450 parts by mass of isopropanol in a reaction vessel and react at 65°C for 2.5 hours. After the reaction is complete, remove the solvent by rotary evaporation of the reaction solution, and wash the remaining solid with deionized water and dry it to obtain the flame retardant.

[0060] The second step involves mixing 60 parts by mass of flame retardant, 36 parts by mass of 2,3-diaminopyridine, and 280 parts by mass of isopropanol in a reaction vessel and reacting at 75°C for 9 hours. After the reaction is complete, the solvent is removed by rotary evaporation of the reaction solution, and the remaining solid is recrystallized with anhydrous ethanol to obtain the compatibilizing flame retardant.

[0061] Step 3: By mass, mix 100 parts of polytetrahydrofuran ether diol 1400, 50 parts of isophorone diisocyanate, 1.25 parts of dibutyltin dilaurate, and 450 parts of isopropanol and react at 60°C for 2 hours. Then, add 17.5 parts of compatibilizer and flame retardant to the system and continue to react at 60°C for 50 minutes. After the reaction is completed, remove the isopropanol by rotary evaporation to obtain flame-retardant polyurethane.

[0062] Step 4: By weight, 100 parts of nylon 66 resin, 21.5 parts of compatibilizer and flame retardant and 0.55 parts of antioxidant 1035 are mixed and melt-extruded at a temperature of 245℃ and then spun to obtain flame retardant nylon fiber. The flame retardant nylon fiber is then woven to obtain nylon base fabric.

[0063] Step 5: Using a 60% (v / v) isopropanol aqueous solution as a solvent, immerse the nylon base fabric in the solvent and allow it to swell for 3 minutes at 50°C. Then remove the nylon base fabric and apply a coating at a rate of 20 g / m². 2 The standard involves coating the swollen nylon base fabric with a flame-retardant polyurethane emulsion, followed by curing at 100°C for 1.5 hours to obtain a flame-retardant composite material.

[0064] In this embodiment, the flame-retardant polyurethane emulsion is obtained by mixing the following raw materials: 100 parts flame-retardant polyurethane, 10 parts isopropanol, and 1.25 parts thickener, wherein the thickener used is thickener RM-8W.

[0065] Application of a flame-retardant composite material prepared by the above steps in the field of bottle cap straps.

[0066] Example 5

[0067] A method for preparing a flame-retardant composite material for a bottle cap strap in a pack includes the following steps:

[0068] Step 1: Mix 75 parts by mass of 2-chloroethyl dichlorophosphoric acid, 25 parts by mass of pentaerythritol, 70 parts by mass of triethylamine and 450 parts by mass of isopropanol in a reaction vessel and react at 80°C for 2 hours. After the reaction is complete, remove the solvent by rotary evaporation of the reaction solution, and wash the remaining solid with deionized water and dry it to obtain the flame retardant.

[0069] The second step involves mixing 60 parts by mass of flame retardant, 36 parts by mass of 2,3-diaminopyridine, and 280 parts by mass of isopropanol in a reaction vessel and reacting at 90°C for 6 hours. After the reaction is complete, the solvent is removed by rotary evaporation of the reaction solution, and the remaining solid is recrystallized with anhydrous ethanol to obtain the compatibilizing flame retardant.

[0070] Step 3: By mass, mix 100 parts of polytetrahydrofuran ether diol 1000, 60 parts of diphenylmethane diisocyanate / isophorone diisocyanate, 2 parts of dibutyltin dilaurate, and 480 parts of isopropanol and react at 70°C for 1 hour. Then, add 20 parts of compatibilizer flame retardant to the system and continue to react at 70°C for 40 minutes. After the reaction is completed, remove the isopropanol by rotary evaporation to obtain flame-retardant polyurethane.

[0071] Step 4: By mass, 100 parts of nylon 66 resin, 25 parts of compatibilizer and flame retardant, and 0.8 parts of antioxidant 1076 are mixed and melt-extruded at a temperature of 260℃. The mixture is then spun to obtain flame-retardant nylon fiber, which is then woven to obtain nylon base fabric.

[0072] Step 5: Using a 70% (v / v) isopropanol aqueous solution as a solvent, immerse the nylon base fabric in the solvent and allow it to swell at 60°C for 1 minute. Then remove the nylon base fabric and apply a coating at a rate of 25 g / m². 2 The standard involves coating the swollen nylon base fabric with a flame-retardant polyurethane emulsion, followed by curing at 120°C for 1 hour to obtain a flame-retardant composite material.

[0073] In this embodiment, the flame-retardant polyurethane emulsion is obtained by mixing the following raw materials: 100 parts flame-retardant polyurethane, 12 parts isopropanol, and 2 parts thickener, wherein the thickener used is hydroxyethyl cellulose.

[0074] Application of a flame-retardant composite material prepared by the above steps in the field of bottle cap straps.

[0075] Example 6

[0076] A method for preparing a flame-retardant composite material for a bottle cap strap in a pack includes the following steps:

[0077] Step 1: Mix 75 parts by mass of 2-chloroethyl dichlorophosphoric acid, 25 parts by mass of pentaerythritol, 70 parts by mass of triethylamine and 450 parts by mass of isopropanol in a reaction vessel and react at 80°C for 2 hours. After the reaction is complete, remove the solvent by rotary evaporation of the reaction solution, and wash the remaining solid with deionized water and dry it to obtain the flame retardant.

[0078] The second step involves mixing 60 parts by mass of flame retardant, 36 parts by mass of 2,3-diaminopyridine, and 280 parts by mass of isopropanol in a reaction vessel and reacting at 90°C for 6 hours. After the reaction is complete, the solvent is removed by rotary evaporation of the reaction solution, and the remaining solid is recrystallized with anhydrous ethanol to obtain the compatibilizing flame retardant.

[0079] Step 3: By mass, mix 100 parts of polytetrahydrofuran ether diol 1000, 60 parts of diphenylmethane diisocyanate / isophorone diisocyanate, 2 parts of dibutyltin dilaurate, and 480 parts of isopropanol and react at 70°C for 1 hour. Then, add 20 parts of compatibilizer flame retardant to the system and continue to react at 70°C for 40 minutes. After the reaction is completed, remove the isopropanol by rotary evaporation to obtain flame-retardant polyurethane.

[0080] Step 4: By mass, 100 parts of nylon 66 resin, 25 parts of compatibilizer and flame retardant, and 0.8 parts of antioxidant 1076 are mixed and melt-extruded at a temperature of 260℃. The mixture is then spun to obtain flame-retardant nylon fiber, which is then woven to obtain nylon base fabric.

[0081] Step 5: Using a 70% (v / v) isopropanol aqueous solution as a solvent, immerse the nylon base fabric in the solvent and allow it to swell at 60°C for 1 minute. Then remove the nylon base fabric and apply a coating at a rate of 25 g / m². 2 The standard involves coating the swollen nylon base fabric with a flame-retardant polyurethane emulsion, followed by curing at 120°C for 1 hour to obtain a flame-retardant composite material.

[0082] In this embodiment, the flame-retardant polyurethane emulsion is obtained by mixing the following raw materials: 100 parts flame-retardant polyurethane, 12 parts isopropanol, and 2 parts thickener, wherein the thickener used is hydroxyethyl cellulose.

[0083] Application of a flame-retardant composite material prepared by the above steps in the field of bottle cap straps.

[0084] Comparative Example 1

[0085] The difference between this comparative example and Example 1 is that, instead of preparing a compatibilizing flame retardant, an equal mass of commercially available triethyl phosphate flame retardant was used.

[0086] Comparative Example 2

[0087] The difference between this comparative example and Example 2 is that, instead of preparing a compatibilizing flame retardant, an equal mass of commercially available triethyl phosphate flame retardant was used.

[0088] Experimental Example

[0089] The flame-retardant composite materials obtained in Examples 1-6 and Comparative Examples 1-2 were subjected to performance tests. The tensile strength and elongation at break of the nylon base fabric in each component example were tested according to the national standard GB / T 3923.1-2013 "Textiles - Tensile Properties of Fabrics". The peel strength of the flame-retardant polyurethane coating on the surface of the flame-retardant composite material in each component example was tested according to the standard ASTM D751 "Standard Test Methods for Coated Fabrics". The limiting oxygen index of the flame-retardant composite material in each example was tested according to the national standard GB / T 5455-2014 "Determination of Vertical Destruction Length, Afterflame and Afterflame Time of Textiles". The test results are shown in Table 1.

[0090] Table 1

[0091]

[0092] The preparation method and application of a flame-retardant composite material for a pack bottle strap provided by the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention, including the best mode, and also to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combination method. It should be noted that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention. In particular, as long as there is no structural conflict, the various features in the embodiments disclosed in the present invention can be combined with each other in any way. The lack of an exhaustive description of these combinations in this specification is merely for the sake of brevity and resource conservation. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for preparing a flame-retardant composite material for a bottle cap strap in a pack, characterized in that, Includes the following steps: The first step involves reacting 2-chloroethyl dichlorophosphoric acid with pentaerythritol to obtain a flame retardant; The second step is to react the flame retardant with 2,3-diaminopyridine to obtain the compatibilizing flame retardant; The third step involves polymerizing the raw materials polytetrahydrofuran ether diol, polyisocyanate, dibutyltin dilaurate, and compatibilizer / flame retardant to obtain flame retardant polyurethane. Step 4: Mix nylon resin, compatibilizer, flame retardant, and antioxidant, and then melt extrude and spin to obtain flame retardant nylon fiber. The flame retardant nylon fiber is then woven to obtain nylon base fabric. Step 5: After swelling the nylon base fabric, remove the nylon base fabric and coat the surface of the swollen nylon base fabric with flame-retardant polyurethane emulsion, and then cure it to obtain a flame-retardant composite material.

2. The method for preparing a flame-retardant composite material for a bottle strap in a pack according to claim 1, characterized in that, The temperature conditions for the melt extrusion are 230–260°C.

3. The method for preparing a flame-retardant composite material for a bottle cap strap in a pack according to claim 1, characterized in that, The swelling conditions are as follows: using a 50-70% volume fraction of isopropanol aqueous solution as a solvent, immersing the nylon base fabric in the solvent, and swelling at a temperature of 40-60°C for 1-5 minutes.

4. The method for preparing a flame-retardant composite material for a bottle cap strap in a pack according to claim 1, characterized in that, The curing conditions are as follows: curing at a temperature of 80–120°C for 1–2 hours.

5. A method for preparing a flame-retardant composite material for a bottle cap strap in a pack according to claim 1, characterized in that, The mass ratio of nylon resin, compatibilizer, flame retardant, and antioxidant used is 100:18-25:0.3-0.

8.

6. A method for preparing a flame-retardant composite material for a bottle strap in a pack according to claim 1, characterized in that, The mass ratio of polytetrahydrofuran ether diol, polyisocyanate, dibutyltin dilaurate, and compatibilizer / flame retardant used is 100:40-60:0.5-2:15-20.

7. A method for preparing a flame-retardant composite material for a bottle cap strap in a pack according to claim 1, characterized in that, The polyisocyanate is at least one of diphenylmethane diisocyanate and isophorone diisocyanate.

8. A method for preparing a flame-retardant composite material for a bottle strap in a pack according to claim 1, characterized in that, The flame-retardant polyurethane emulsion comprises the following raw materials in parts by weight: 100 parts flame-retardant polyurethane, 8-12 parts isopropanol, and 0.5-2 parts thickener.

9. A method for preparing a flame-retardant composite material for a bottle strap in a pack according to claim 1, characterized in that, The coating amount of the flame-retardant polyurethane emulsion is 15-25 g / m³. 2 .

10. The application of a flame-retardant composite material prepared by any one of claims 1 to 9 in the field of bottle cap straps for packs.

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