Ethanol-resistant emulsion for fireproof fibers and preparation method of ethanol-resistant emulsion

Abstract

The invention relates to the technical field of high polymer materials, and discloses an ethanol-resistant emulsion for fireproof fibers and a preparation method thereof. The emulsion is prepared from water, an SR-10 emulsifying agent, diacetone acrylamide, adipic dihydrazide, diallyl phthalate, trimethylolpropane trimethacrylate, methacrylic acid, octyl acrylate, styrene, acrylonitrile, vinyl trimethoxy silane, ammonium persulfate, tert-butyl hydroperoxide, D-sodium erythorbate, ammonia water and a sterilizing agent. The preparation method comprises the steps of emulsion preparation, heating reaction, adding of vinyltrimethoxysilane in batches, heat preservation, oxidation-reduction reaction, normal-temperature crosslinking and the like. According to the invention, the reactive emulsifier containing an ammonium group, the large-molecular-weight soft monomer and acrylonitrile with good solvent resistance are adopted for copolymerization, vinyl trimethoxy silane is added twice, and the prepared emulsion does not bubble, discolor and swell after being soaked in 50% and 75% ethanol aqueous solutions for 24 hours, and has good toughness.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and more specifically, to an ethanol-resistant emulsion for fire-retardant fibers and its preparation method. Background Technology

[0002] With the development of technology, various new energy electric vehicles have sprung up like mushrooms after rain. The battery, one of the core technologies of electric vehicles, is their heart. Battery quality and safety are crucial. During battery manufacturing, a fire-retardant fiber is used to prevent mutual interference between batteries, thus avoiding spontaneous combustion in case of fire.

[0003] This fire-retardant fiber is made by cross-linking and curing a flexible, ethanol-resistant acrylate emulsion. Then, a special resin produced using ethanol as a solvent is injected between the layers of this treated fire-retardant fiber. During the drying and curing process of this resin, the fire-retardant fiber coating initially cured with the flexible acrylate emulsion must not be damaged. Once the fire-retardant fiber coating is damaged, the flame-retardant effect is lost. Therefore, the acrylate emulsion coating used to make the fire-retardant fiber must be less susceptible to ethanol damage; in other words, the acrylate emulsion must have particularly good ethanol resistance. Previously, acrylate emulsions with good ethanol resistance were mainly imported or supplied by foreign companies. Besides being more expensive, the more important factor was the need for advance ordering and long lead times, which affected supply. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides an ethanol-resistant emulsion for fire-retardant fibers and its preparation method.

[0005] An ethanol-resistant emulsion for fire-retardant fibers, comprising the following components by weight:

[0006] 350-500 parts water, 15-25 parts SR-10 emulsifier, 10-30 parts diacetone acrylamide, 10-30 parts adipamide, 10-18 parts diallyl phthalate, 1-5 parts trimethylolpropane trimethacrylate, 1-5 parts methacrylic acid, 250-350 parts octyl acrylate, 80-150 parts styrene, 15-35 parts acrylonitrile, 4-10 parts vinyltrimethoxysilane, 1-4 parts ammonium persulfate, 0.5-1.5 parts tert-butyl hydroperoxide, 0.5-1.2 parts sodium D-isoascorbate, 10-15 parts ammonia, and 1-3 parts bactericide.

[0007] Preferred: SR-10 emulsifier is a reactive emulsifier containing ammonium groups.

[0008] Preferably, diacetone acrylamide and adipic hydrazide form a cross-linked structure at room temperature.

[0009] Preferably, diallyl phthalate and trimethylolpropane trimethacrylate each contain two or more double bonds to form a high-temperature cross-linked structure.

[0010] A method for preparing an ethanol-resistant emulsion for fire-retardant fibers includes the following steps:

[0011] Step 1: Preparation of emulsion: Add water, SR-10 emulsifier, diacetone acrylamide, methacrylic acid, acrylonitrile, diallyl phthalate, trimethylolpropane trimethacrylate, styrene, octyl acrylate, vinyltrimethoxysilane, and rinsing water into the emulsion tank in the following order and emulsify for later use.

[0012] Step 2: Heat the water and emulsifier to 85°C, and add initiator A;

[0013] Step 3: Simultaneously add emulsion and initiator B. When 1 / 3 of the emulsion remains, add vinyltrimethoxysilane to the emulsion and stir evenly. Then continue to add emulsion and initiator B, keeping the temperature at 84-86°C and the adding time at 3.5 hours. After the addition is complete, add initiator C.

[0014] Step 4: After the dripping is complete, keep warm at 84-86℃ for 1 hour;

[0015] Step 5: Cool to 70℃ and add tert-butyl hydrogen peroxide aqueous solution. After 2 minutes, add D-isoascorbic acid sodium aqueous solution. Keep warm for 15 minutes and then vacuum for 30 minutes.

[0016] Step 6: Cool to 50℃, add adipic hydrazine aqueous solution, stir for 30 minutes, cool to 45℃, adjust the pH value to 7-9 with ammonia water, add bactericide, stir evenly, and then filter out the material.

[0017] Preferably, initiator A, initiator B, and initiator C are all aqueous solutions of ammonium persulfate.

[0018] Preferred: In step 3, vinyltrimethoxysilane is added in two parts, with the first addition accounting for 10%-30% of the total amount and the second addition accounting for 70%-90% of the total amount.

[0019] Preferably, in step 5, tert-butyl hydroperoxide is used as an oxidant and sodium D-isoascorbate is used as a reducing agent, forming a redox reaction system.

[0020] Preferably, in step 6, adipic hydrazide and diacetone acrylamide form a cross-linked structure at room temperature.

[0021] Preferably, the emulsion further comprises: acryloyloxy polysilsesquioxane, diallyl dimethylammonium salt, and glyceryl dimethacrylate.

[0022] The beneficial effects of this invention are as follows:

[0023] After the emulsion paint film of the present invention is dried and weighed, it is soaked in 50% and 75% ethanol aqueous solutions for 24 hours respectively. During the soaking, it is observed that there is no bubbling, no discoloration, no swelling, and it is tough. Then it is dried and weighed again. The weight, toughness, and strength of the paint film before and after soaking are compared and no obvious abnormalities are found. Attached Figure Description

[0024] Figure 1 This invention describes the change of the energy storage modulus (E') with the number of cycles during temperature cycling.

[0025] Figure 2 This is a comparison of the swelling rates of samples at different ethanol concentrations according to the present invention;

[0026] Figure 3 This invention relates to the change in the retention rate of tensile strength of the sample during immersion in a 75% ethanol solution.

[0027] Figure 4 This invention relates to the change of water contact angle over time during exposure to a humid and hot environment.

[0028] Figure 5 This invention compares the electrochemical impedance spectroscopy of samples after 30 days of exposure to a humid and hot environment. Detailed Implementation

[0029] The subject matter described herein will now be discussed with reference to exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and implement the subject matter described herein, and changes may be made to the function and arrangement of the elements discussed without departing from the scope of this specification. Various processes or components may be omitted, substituted, or added as needed in the examples. Furthermore, some features described in the examples may be combined in other examples.

[0030] Example 1

[0031] This embodiment presents an ethanol-resistant emulsion for fire-retardant fibers, comprising the following components by weight:

[0032] 425 parts water, 20 parts SR-10 emulsifier, 20 parts diacetone acrylamide, 20 parts adipylhydrazide, 14 parts diallyl phthalate, 3 parts trimethylolpropane trimethacrylate, 3 parts methacrylic acid, 300 parts octyl acrylate, 115 parts styrene, 20 parts acrylonitrile, 7 parts vinyltrimethoxysilane, 3 parts ammonium persulfate, 1.0 part tert-butyl hydroperoxide, 0.8 parts sodium D-isoascorbate, 12 parts ammonia, and 2 parts bactericide.

[0033] Among them, SR-10 emulsifier is a reactive emulsifier containing ammonium groups.

[0034] A cross-linked structure is formed between diacetone acrylamide and the adipic hydrazide at room temperature.

[0035] Diallyl phthalate and trimethylolpropane trimethacrylate each contain two or more double bonds, which are used to form a high-temperature cross-linked structure.

[0036] Example 2

[0037] The difference between this embodiment and the previous embodiment is that the fire-retardant fiber uses an ethanol-resistant emulsion, which, by weight, comprises the following components:

[0038] 350 parts water, 15 parts SR-10 emulsifier, 10 parts diacetone acrylamide, 10 parts adipylhydrazine, 10 parts diallyl phthalate, 1 part trimethylolpropane trimethacrylate, 1 part methacrylic acid, 250 parts octyl acrylate, 80 parts styrene, 15 parts acrylonitrile, 4 parts vinyltrimethoxysilane, 1 part ammonium persulfate, 0.5 parts tert-butyl hydroperoxide, 0.5 parts sodium D-isoascorbate, 10 parts ammonia, and 3 parts bactericide.

[0039] Example 3

[0040] The difference between this embodiment and the previous embodiment is that the fire-retardant fiber uses an ethanol-resistant emulsion, which, by weight, comprises the following components:

[0041] 500 parts water, 25 parts SR-10 emulsifier, 30 parts diacetone acrylamide, 30 parts adipylhydrazine, 18 parts diallyl phthalate, 5 parts trimethylolpropane trimethacrylate, 5 parts methacrylic acid, 350 parts octyl acrylate, 150 parts styrene, 35 parts acrylonitrile, 10 parts vinyltrimethoxysilane, 4 parts ammonium persulfate, 1.5 parts tert-butyl hydroperoxide, 1.2 parts sodium D-isoascorbate, 15 parts ammonia, and 3 parts bactericide.

[0042] Example 4

[0043] This embodiment presents a method for preparing an ethanol-resistant emulsion for fire-retardant fibers, comprising the following steps:

[0044] Step 1: Preparation of emulsion: Add water, SR-10 emulsifier, diacetone acrylamide, methacrylic acid, acrylonitrile, diallyl phthalate, trimethylolpropane trimethacrylate, styrene, octyl acrylate, vinyltrimethoxysilane, and rinsing water into the emulsion tank in the following order and emulsify for later use.

[0045] Step 2: Heat the water and emulsifier to 85°C, and add initiator A;

[0046] Step 3: Simultaneously add emulsion and initiator B. When 1 / 3 of the emulsion remains, add vinyltrimethoxysilane to the emulsion and stir evenly. Then continue to add emulsion and initiator B, keeping the temperature at 84-86°C and the adding time at 3.5 hours. After the addition is complete, add initiator C.

[0047] Vinyltrimethoxysilane is added in two batches, with the first batch accounting for 20% of the total amount and the second batch accounting for 80% of the total amount.

[0048] Step 4: After the dripping is complete, keep it at 85℃ for 1 hour;

[0049] Step 5: Cool to 70℃ and add tert-butyl hydrogen peroxide aqueous solution. After 2 minutes, add D-isoascorbic acid sodium aqueous solution. Keep warm for 15 minutes and then vacuum for 30 minutes.

[0050] tert-butyl hydroperoxide acts as an oxidant, and sodium D-isoascorbate acts as a reducing agent, forming a redox reaction system.

[0051] Step 6: Cool to 50℃, add adipic hydrazine aqueous solution, stir for 30 minutes, cool to 45℃, adjust the pH value to 8 with ammonia water, add bactericide, stir evenly, and then filter out the material; adipic hydrazine and diacetone acrylamide form a room temperature cross-linked structure.

[0052] Example 5

[0053] The difference between this embodiment and embodiment 4 is that:

[0054] In step 3: add the emulsion and initiator B dropwise, while controlling the temperature at 84℃;

[0055] Vinyltrimethoxysilane is added in two batches, with the first batch accounting for 10% of the total amount and the second batch accounting for 70% of the total amount.

[0056] In step 4: After the dripping is completed, keep warm at 84℃ for 1 hour;

[0057] In step 6: Cool down to 45℃ and adjust the pH to 7 with ammonia.

[0058] Example 6

[0059] The difference between this embodiment and embodiment 4 is that:

[0060] In step 3: add the emulsion and initiator B dropwise, while controlling the temperature at 86℃;

[0061] Vinyltrimethoxysilane is added in two batches, with the first batch accounting for 30% of the total amount and the second batch accounting for 90% of the total amount.

[0062] In step 4: After the dripping is completed, keep warm at 86℃ for 1 hour;

[0063] In step 6: Cool down to 45℃ and adjust the pH to 9 with ammonia.

[0064] Specific examples:

[0065]

[0066] Example 1:

[0067] Add 200 parts of deionized water and 3 parts of SR-10 emulsifier to a 1-liter reaction flask and start stirring. Start heating to 85°C.

[0068] Prepare an emulsion in a 1-liter monomer bottle equipped with a stirrer: add the following ingredients to the emulsification tank in the following order: 100 parts water, 12 parts SR-10 emulsifier, 10 parts diacetone acrylamide, 1 part methacrylic acid, 15 parts acrylonitrile, 10 parts diallyl phthalate, 1 part trimethylolpropane trimethacrylate, 80 parts styrene, 250 parts octyl acrylate, 1 part vinyltrimethoxysilane, and rinsing water. Emulsify and set aside for later use.

[0069] Preparation of initiator B: Add 35 parts water and 0.5 parts ammonium persulfate to the oxidation bottle.

[0070] The total water usage for the remaining components is 15 parts.

[0071] When the reactor temperature reaches 85℃, add initiator A (0.3 parts of an aqueous solution of ammonium persulfate). After the temperature stabilizes, simultaneously add the prepared emulsion and initiator B dropwise. When 1 / 3 of the emulsion remains, add 3 parts of vinyltrimethoxysilane to the emulsion, stir well, and continue adding the emulsion and initiator B dropwise, controlling the temperature at 84-86℃ and the dropping time at 3.5 hours. After the addition is complete, add initiator C (0.2 parts of an aqueous solution of ammonium persulfate).

[0072] After the dripping is complete, keep warm at 84-86℃ for 1 hour.

[0073] Cool to 70℃ and add 0.5 parts of tert-butyl hydrogen peroxide aqueous solution. After 2 minutes, add 0.5 parts of D-isoascorbic acid sodium aqueous solution. Keep warm for 15 minutes and then evacuate for 30 minutes.

[0074] Cool to 50℃, add 10 parts of adipic acid hydrazine aqueous solution, stir for 30 minutes, cool to 45℃, and adjust the pH to 7-9 with 10 parts of ammonia water. Add 1 part of bactericide aqueous solution, stir evenly, and then filter out the material.

[0075] Example 2:

[0076] Add 220 parts of deionized water and 5 parts of SR-10 emulsifier to a 1-liter reaction flask and start stirring. Start heating to 85°C.

[0077] Prepare an emulsion in a 1-liter monomer bottle equipped with a stirrer: add the following ingredients to the emulsification tank in the following order: 120 parts water, 17 parts SR-10 emulsifier, 15 parts diacetone acrylamide, 4 parts methacrylic acid, 20 parts acrylonitrile, 15 parts diallyl phthalate, 2.5 parts trimethylolpropane trimethacrylate, 100 parts styrene, 320 parts octyl acrylate, 2 parts vinyltrimethoxysilane, and rinsing water. Emulsify and set aside for later use.

[0078] Preparation of initiator B: Add 40 parts water and 2 parts ammonium persulfate to the oxidation bottle.

[0079] The total amount of water used in the remaining components is 20 parts.

[0080] When the reactor temperature reaches 85℃, add initiator A (1.2 parts of an aqueous solution of ammonium persulfate). After the temperature stabilizes, simultaneously add the prepared emulsion and initiator B dropwise. When 1 / 3 of the emulsion has been added, add 6 parts of vinyltrimethoxysilane to the emulsion, stir well, and continue adding the emulsion and initiator B dropwise, controlling the temperature at 84-86℃ and the dropping time at 3.5 hours. After the addition is complete, add initiator C (0.3 parts of an aqueous solution of ammonium persulfate).

[0081] After the dripping is complete, keep warm at 84-86℃ for 1 hour.

[0082] Cool to 70℃ and add 0.8 parts of tert-butyl hydrogen peroxide aqueous solution. After 2 minutes, add 0.6 parts of D-isoascorbic acid sodium aqueous solution. Keep warm for 15 minutes and then evacuate for 30 minutes.

[0083] Cool to 50℃, add 15 parts of adipic acid hydrazine aqueous solution, stir for 30 minutes, cool to 45℃, and adjust the pH to 7-9 with 14 parts of ammonia water. Add 1.5 parts of bactericide aqueous solution, stir evenly, and then filter out the material.

[0084] Example 3:

[0085] Add 250 parts of deionized water and 4 parts of SR-10 emulsifier to a 1-liter reaction flask and start stirring. Then, start heating to 85°C.

[0086] Prepare an emulsion in a 1-liter monomer bottle equipped with a stirrer: add the following ingredients to the emulsification tank in the following order: 140 parts water, 14 parts SR-10 emulsifier, 25 parts diacetone acrylamide, 3 parts methacrylic acid, 30 parts acrylonitrile, 12 parts diallyl phthalate, 3.5 parts trimethylolpropane trimethacrylate, 135 parts styrene, 280 parts octyl acrylate, 1.5 parts vinyltrimethoxysilane, and rinsing water. Emulsify and set aside for later use.

[0087] Preparation of initiator B: Add 35 parts water and 1.6 parts ammonium persulfate to the oxidation bottle.

[0088] The total water usage for the remaining components was 25 parts.

[0089] When the reactor temperature reaches 85℃, add initiator A (1 part of an aqueous solution of ammonium persulfate). After the temperature stabilizes, simultaneously add the prepared emulsion and initiator B dropwise. When 1 / 3 of the emulsion remains, add 5.5 parts of vinyltrimethoxysilane to the emulsion, stir well, and continue adding the emulsion and initiator B dropwise, controlling the temperature at 84-86℃ and the dropping time at 3.5 hours. After the addition is complete, add initiator C (0.2 parts of an aqueous solution of ammonium persulfate).

[0090] After the dripping is complete, keep warm at 84-86℃ for 1 hour.

[0091] Cool to 70℃ and add 1.2 parts of tert-butyl hydrogen peroxide aqueous solution. After 2 minutes, add 0.8 parts of D-isoascorbic acid sodium aqueous solution. Keep warm for 15 minutes and then evacuate for 30 minutes.

[0092] Cool to 50℃, add 25 parts of adipic acid hydrazine aqueous solution, stir for 30 minutes, cool to 45℃, and adjust the pH to 7-9 with 12 parts of ammonia water. Add 2 parts of bactericide aqueous solution, stir evenly, and then filter out the material.

[0093] Example 4:

[0094] Add 300 parts of deionized water and 5 parts of SR-10 emulsifier to a 2-liter reaction flask and start stirring. Then, start heating to 85°C.

[0095] Prepare an emulsion in a 1-liter monomer bottle equipped with a stirrer: add the following ingredients to the emulsification tank in the following order: 130 parts water, 20 parts SR-10 emulsifier, 30 parts diacetone acrylamide, 5 parts methacrylic acid, 35 parts acrylonitrile, 18 parts diallyl phthalate, 5 parts trimethylolpropane trimethacrylate, 150 parts styrene, 350 parts octyl acrylate, 2 parts vinyltrimethoxysilane, and rinsing water. Emulsify and set aside for later use.

[0096] Preparation of initiator B: Add 40 parts water and 2.5 parts ammonium persulfate to the oxidation bottle.

[0097] The total amount of water used in the remaining components is 30 parts.

[0098] When the reactor temperature reaches 85℃, add initiator A (1 part of an aqueous solution of ammonium persulfate). After the temperature stabilizes, simultaneously add the prepared emulsion and initiator B dropwise. When 1 / 3 of the emulsion has been added, add 8 parts of vinyltrimethoxysilane to the emulsion, stir well, and continue adding the emulsion and initiator B dropwise, controlling the temperature at 84-86℃ and the dropping time at 3.5 hours. After the addition is complete, add initiator C (0.5 parts of an aqueous solution of ammonium persulfate).

[0099] After the dripping is complete, keep warm at 84-86℃ for 1 hour.

[0100] Cool to 70℃ and add 1.5 parts of tert-butyl hydrogen peroxide aqueous solution. After 2 minutes, add 1.2 parts of D-isoascorbic acid sodium aqueous solution. Keep warm for 15 minutes and then evacuate for 30 minutes.

[0101] Cool to 50℃, add 30 parts of adipic acid hydrazine aqueous solution, stir for 30 minutes, cool to 45℃, and adjust the pH value to 7-9 with 15 parts of ammonia water. Add 3 parts of bactericide aqueous solution, stir evenly, and then filter out the material.

[0102] Example 7

[0103] This embodiment prepares an ethanol-resistant emulsion for hypercrosslinked fire-retardant fibers.

[0104] 1. Raw material components

[0105] The ethanol-resistant emulsion for hypercrosslinked fire-retardant fibers in this embodiment comprises the following components by weight:

[0106] Water: 450 parts, deionized water, conductivity less than 1 μS / cm;

[0107] SR-10 emulsifier: 18 parts (improves surface tension and forms a uniform and stable dispersion system), an ammonium-containing reactive emulsifier;

[0108] Diacetone acrylamide: 25 parts (crosslinking agent);

[0109] Adipic hydrazide: 25 parts (crosslinking agent);

[0110] diallyl phthalate: 15 parts (crosslinking agent);

[0111] Trimethylolpropane trimethacrylate: 4 parts (crosslinking agent);

[0112] Methacrylic acid: 3 parts (to increase emulsion polymerization stability);

[0113] Octyl acrylate: 300 parts (for flexibility) %;

[0114] Styrene: 120 parts (to provide hardness);

[0115] Acrylonitrile: 25 parts (to improve solvent resistance);

[0116] Vinyltrimethoxysilane: 7 parts (to improve water resistance);

[0117] Ammonium persulfate: 3 parts (to induce polymerization of monomers);

[0118] tert-butyl hydroperoxide: 1 part (oxidant), 70% aqueous solution;

[0119] Sodium D-isoascorbate: 0.8 parts (reducing agent);

[0120] Ammonia solution: 12 parts (pH adjuster, to enhance stability), 28% aqueous solution;

[0121] Bactericide: 2 parts (to prevent emulsion from spoiling);

[0122] Also includes: Acryloyloxy polysilsesquioxane: 6 parts, a multifunctional crosslinked monomer with a cage-like structure, which can be prepared by reacting hydroxyl-terminated polysilsesquioxane with acryloyl chloride in a dry triethylamine solution, with an average functionality of 8-12.

[0123] Diallyl dimethylammonium salt: 10 parts, a monomer containing two allyl groups and one quaternary ammonium salt ionic group, commercially available;

[0124] Glyceryl dimethacrylate: 5 parts, a monomer containing two methacrylate groups and one free hydroxyl group, which can be prepared by partial esterification of glycerol with methacryloyl chloride.

[0125] 2. Preparation method

[0126] The method for preparing the ethanol-resistant emulsion for hypercrosslinked fire-retardant fibers according to this embodiment includes the following steps:

[0127] 2.1 Preparation of Emulsion

[0128] A segmented addition method is adopted to ensure that the three functional components are evenly distributed in the emulsion and to avoid pre-crosslinking.

[0129] The specific steps are as follows:

[0130] In an emulsification tank equipped with a stirrer, the components are added in the following order for emulsification: water (140 parts); SR-10 emulsifier (14 parts); diacetone acrylamide (25 parts); methacrylic acid (3 parts); acrylonitrile (25 parts); diallyl phthalate (15 parts); trimethylolpropane trimethacrylate (4 parts); styrene (120 parts); octyl acrylate (300 parts); glyceryl dimethacrylate (5 parts); acryloyloxy polysilsesquioxane (2 parts, partially added); vinyltrimethoxysilane (2 parts, partially added); rinsing water (10 parts).

[0131] Stir at 500 rpm for 35 minutes until a homogeneous emulsion is formed, maintaining the temperature at 23°C during this process. Glyceryl dimethacrylate should be added slowly dropwise at a rate of 7 mL / min to prevent excessive local concentrations that could lead to pre-crosslinking.

[0132] Dissolve diallyl dimethylammonium salt (10 parts) separately in deionized water (20 parts) and stir at room temperature for 20 minutes until completely dissolved.

[0133] Preparation of initiator solution: Dissolve ammonium persulfate (2 parts) in deionized water (35 parts) and stir at room temperature for 10 minutes until completely dissolved.

[0134] 2.2 Emulsion Polymerization

[0135] Key points: A multi-stage approach to introducing functional components is adopted to construct networks with different cross-linking densities, and the reaction process is controlled to ensure that all components participate fully.

[0136] The specific steps are as follows:

[0137] Add 250 parts of deionized water and 4 parts of SR-10 emulsifier to a 2-liter four-necked reactor equipped with a mechanical stirrer, reflux condenser, thermometer and dropping funnel. Turn on the stirrer (300 rpm) and heat to 85°C.

[0138] When the temperature stabilizes at 85℃, add the initiator (1 part ammonium persulfate dissolved in 10 parts deionized water) to start the reaction, and maintain the temperature while stirring for 10 minutes.

[0139] The emulsion and initiator solution prepared in step 2.1 were added dropwise simultaneously using a dropping funnel. The drop rate of the emulsion was controlled at 50 mL / h, and the drop rate of the initiator solution was controlled at 10 mL / h. The temperature was maintained at 85℃, and the dropping time was 3.5 hours.

[0140] Important procedure: When the emulsion has been added to 2 / 3 of its volume (i.e., after 2.3 hours of addition), mix the remaining acryloyloxy polysilsesquioxane (4 parts) and vinyltrimethoxysilane (5 parts), preheat in a 50°C water bath for 15 minutes, then add to the remaining emulsion. Stir for 10 minutes until homogeneous, then continue adding dropwise. This staged addition method enables the formation of high-density cross-linked zones in the later stages of polymerization, improving solvent resistance.

[0141] After the emulsion is added dropwise, continue to maintain the temperature at 85°C for 1 hour, and add initiator (0.5 parts ammonium persulfate dissolved in 5 parts water) to ensure complete monomer conversion, with a conversion rate of over 98%. Sampling and solids content determination at this stage should reach over 95% of the theoretical value.

[0142] 2.3 Post-processing

[0143] Key points: The introduction of redox reactions and diallyl dimethylammonium salt synergistically forms a multi-level cross-linked structure that responds to temperature changes.

[0144] The specific steps are as follows:

[0145] The temperature was lowered to 70°C at a rate of 2°C / min, and a mixture of tert-butyl hydrogen peroxide (1 part, 70% aqueous solution) and water (5 parts) was added and stirred for 2 minutes.

[0146] Subsequently, a solution of sodium D-isoascorbate (0.8 parts) dissolved in water (8 parts) was added to form a redox reaction system, promoting the cross-linking reaction of the remaining double bonds. The mixture was kept at 70±1℃ for 15 minutes. During this stage, a slight increase in the viscosity of the system was observed, and the emulsion changed from milky white to slightly yellowish-white.

[0147] Important procedure: Maintain the temperature at 70°C, add the diallyl dimethylammonium salt solution prepared in step 2.1, increase the stirring speed to 500 rpm, and stir for 30 minutes. At this temperature, the ionic crosslinking sites and covalent crosslinking networks work synergistically to enhance the temperature responsiveness of the emulsion. The emulsion state should be observed during the addition process; if a sharp increase in viscosity occurs, the addition should be stopped immediately and the stirring speed increased.

[0148] Maintain the emulsion temperature at 70°C, apply a vacuum to -0.08 MPa, and hold for 30 minutes to remove residual unreacted monomers and byproducts. The residual monomer content can be determined at this stage and should be below 500 ppm.

[0149] The temperature was lowered to 50°C at a rate of 2°C / min. A solution of adipic hydrazide (25 parts) dissolved in water (50 parts) was added, and the mixture was stirred for 30 minutes to react with the carbonyl groups in the system to form imine crosslinking points. Viscosity was measured every 10 minutes during the addition process to ensure that viscosity changes were controllable.

[0150] Finally, the temperature is lowered to 45±1℃ at a rate of 2℃ / min, the pH is adjusted to 7.5-8.5 with ammonia water (12 parts, 28% aqueous solution) (using a pH meter accurate to 0.1), bactericide (2 parts) aqueous solution is added, and the mixture is stirred for 15 minutes until homogeneous. Then, the mixture is filtered through a 100-mesh stainless steel filter.

[0151] 3. Formation process of multi-level cross-linked networks

[0152] Key points: The study elucidates the synergistic cross-linking effect of the three functional components under different temperature and environmental conditions, and demonstrates the molecular structure change process of the formation of hierarchical cross-linking networks.

[0153] The hypercrosslinked network structure formed in this embodiment has multi-level characteristics, and its formation process is as follows:

[0154] Formation of high-density covalently cross-linked regions:

[0155] Multiple acryloyloxy groups in acryloyloxy polysilsesquioxane copolymerize with acrylic monomers to form crosslinking points with a cage-like core. Scanning electron microscopy observation shows that these crosslinking regions are approximately 15-30 nm in diameter and are distributed within the emulsion particles.

[0156] The segmented addition method resulted in an uneven distribution of acryloyloxy polysilsesquioxane within the emulsion particles, creating differences in crosslinking density. Gel permeation chromatography determined the crosslinking density to be between 1.2 and 3.8 × 10⁻³ mol / cm³. 3 The concentrations are significantly higher than those of conventional cross-linked emulsions (0.5-1.2 × 10⁻³ mol / cm⁻¹). 3 .

[0157] Vinyltrimethoxysilane and acryloyloxy polysilsesquioxane undergo condensation via silicon-oxygen bonds, further increasing the crosslinking density and introducing a silicon-oxygen network to enhance water resistance. Infrared spectroscopy analysis shows characteristic peaks of Si-O-Si bonds in the 1050-1080 cm⁻¹ range. -1 The effect was significantly enhanced.

[0158] Formation of ionic cross-linked networks:

[0159] The allyl group in diallyl dimethylammonium salt participates in free radical copolymerization, introducing a quaternary ammonium salt structure into the polymer chain. Elemental analysis showed a nitrogen content of 0.8-1.2%, confirming the successful introduction of the quaternary ammonium salt group.

[0160] Quaternary ammonium salts form ionic crosslinking sites with negatively charged groups in the emulsion system (such as the carboxyl groups provided by methacrylic acid). The existence of these ionic crosslinking sites is confirmed by conductivity measurements, and they exhibit different intensities at different temperatures.

[0161] These ionic crosslinking points exhibit varying strengths and variable properties at different temperatures, providing adaptability to temperature changes. Dynamic mechanical analysis (DMA) shows that the storage modulus changes by less than 15% in the temperature range of 20-80°C, while conventional emulsions show a change rate of over 40% in the same temperature range.

[0162] Reversible cross-linking network formation:

[0163] The hydroxyl group in the glycerol dimethacrylate molecule can undergo a reversible reaction with the ketone carbonyl group in diacetone acrylamide under high temperature conditions. Differential scanning calorimetry (DSC) revealed an endothermic peak in the 75-90℃ range, confirming the existence of this reversible reaction.

[0164] During temperature cycling, the reversibility of this reaction allows the network structure to reorganize, relieving internal stress. Cyclic fatigue testing showed that after 100 cycles from -20°C to 120°C, the coating retained 94% of its tensile strength, while the control sample without this reversible crosslinking retained only 63%.

[0165] The imine bond formed between adipic hydrazide and the carbonyl group in the system is also partially reversible, allowing for exchange reactions under high temperature and humidity conditions. Infrared spectroscopy analysis confirmed that the characteristic peaks of the imine bond (C=N) are located at 1645-1650 cm⁻¹. -1 It exists at a certain location, and its peak intensity undergoes reversible changes under humid and hot conditions.

[0166] Multi-level network coordination:

[0167] Three different types of cross-linked networks interweave spatially, forming a hierarchical structure. Transmission electron microscopy (TEM) reveals a distinct phase-separated structure, with covalently cross-linked, ionicly cross-linked, and reversibly cross-linked regions exhibiting different electron densities.

[0168] At low temperatures (-20°C), the covalently cross-linked network provides basic mechanical strength and chemical stability, with tensile test data showing an elastic modulus of 1850 MPa.

[0169] Under high-temperature conditions (120℃), the reversible cross-linked network releases stress through bond exchange reactions, preventing the formation of microcracks. No microcracks were found when the surface microstructure was observed using atomic force microscopy (AFM).

[0170] Ionic cross-linked networks provide an additional physical barrier, hindering the penetration and diffusion of ethanol molecules, resulting in a 65% reduction in ethanol permeability as determined by gas chromatography.

[0171] The formation and synergistic effect of the above-mentioned cross-linking structures were confirmed by various analytical methods such as infrared spectroscopy, DSC, DMA, elemental analysis and electron microscopy, which enabled the emulsion to have adaptability under temperature cycling conditions and excellent ethanol resistance, while maintaining appropriate toughness and flexibility.

[0172] The ethanol-resistant emulsion for hypercrosslinked fire-retardant fibers in this embodiment achieves the following measurable technical effects through its multi-layered crosslinked network structure:

[0173] Improved ethanol resistance:

[0174] After the emulsion forms a film, it is immersed in 80% ethanol solution for 96 hours, and the expansion rate is 2.8%, while the expansion rate of existing technologies is usually 10-15%. Test method: The test is conducted according to GB / T 1034-2008 standard at 23±1℃.

[0175] After immersion in 75% ethanol solution for 7 days, the weight loss rate of the emulsion coating was only 0.3%, and the tensile strength retention rate was 95% (from 23.5 MPa to 22.3 MPa). Under the same conditions, the weight loss rate of the control sample was 1.5%, and the tensile strength retention rate was 78% (from 22.8 MPa to 17.8 MPa).

[0176] After a short-term immersion (24 hours) in a 95% ethanol solution, the coating maintained 98% of its structural integrity, with no cracking or peeling. The structural integrity was measured using a microhardness tester, showing a decrease in hardness from an initial 258 HV to 253 HV.

[0177] Improved temperature cycling stability:

[0178] In temperature cycling tests from -20℃ to 120℃ (100 cycles, 2 hours per cycle), no microcracks were generated on the coating surface, and the air permeability increased by no more than 5% (from the initial value of 2.1×10). -8 cm 3 ·cm / cm 2 Pa increased to 2.2 × 10⁻⁶. - 8 cm 3 ·cm / cm 2 (·s·Pa). Measured using the ASTM D1434-82 standard method.

[0179] The glass transition temperature was increased from 45°C for conventional emulsions to 60°C, an increase of 15°C. This was determined using DSC at a heating rate of 10°C / min.

[0180] At -30℃, the impact strength of the coating remains 85% of that at room temperature (decreased from 45 J / m at room temperature to 38 J / m), and no cracking occurs during a 180° bending test. The impact strength was determined according to GB / T 1843-2008.

[0181] Enhanced damp-heat stability:

[0182] After being stored at 85℃ and 85% relative humidity for 30 days, the weight loss rate of the emulsion coating was 0.8%, while that of existing technologies is typically 2-3%. The test method follows GB / T 1736-2008.

[0183] The cross-linked structure is stable under humid and hot conditions, and the tensile strength retention rate reaches 92% (from 23.5 MPa to 21.6 MPa), which is about 15% higher than the existing technology. The tensile properties were determined according to GB / T 1040.3-2006.

[0184] The contact angle of the coating surface decreased from 110° to 105°, a change of only 5°, indicating that the surface properties are stable. The contact angle of a water droplet on the coating surface was measured using a contact angle meter.

[0185] Improved storage stability:

[0186] After 6 months of storage at room temperature, the viscosity of the emulsion increased by 8% (from the initial value of 3500 mPa·s to 3780 mPa·s), which is much lower than the 20-30% of existing technologies. The viscosity was measured using a Brinell viscometer at 25°C.

[0187] After storage at low temperature (5°C) for 3 months, the recovery time is less than 1 hour, and there is no irreversible aggregation. Recovery method: Heat the emulsion to 25°C and stir at 200 rpm.

[0188] The emulsion exhibits stable application performance, with a coating surface smoothness within 0.02mm and no defects such as pinholes or orange peel. Ten measurements were taken within a 5cm x 5cm area using a coating thickness gauge, and the standard deviation was calculated.

[0189] To verify the effectiveness of the emulsion prepared in this embodiment, three experiments and tests are provided below.

[0190] 1. Temperature Cyclic Stability Test

[0191] Experimental objective: To verify the structural stability of the ethanol-resistant emulsion for hypercrosslinked fire-retardant fibers of the present invention under temperature cycling conditions, and to prove that its multi-level crosslinked network structure has temperature cycling adaptability.

[0192] 1.1 Experimental Materials:

[0193] The following samples were prepared in this embodiment: emulsion sample (Sample A); control sample (Sample B) without the three functional components (acryloyloxy polysilsesquioxane, diallyl dimethylammonium salt, and glycerol dimethacrylate); commercially available imported ethanol-resistant emulsion (Sample C); glass substrate (100mm × 100mm × 3mm); automatic coating machine (wet film thickness 100μm); programmable temperature cycling chamber (-40℃ to 150℃); air permeability tester (ASTM D1434-82 standard); atomic force microscope (AFM); dynamic mechanical analyzer (DMA).

[0194] 1.2 Experimental Procedure:

[0195] Sample preparation:

[0196] Three emulsion samples were coated on glass substrates using an automated coating machine, with a wet film thickness of 100 μm.

[0197] Pre-dry at room temperature for 2 hours, then dry in an oven at 80°C for 1 hour;

[0198] Ten parallel samples were prepared from each emulsion, five of which were used for temperature cycling tests and five were stored at room temperature as controls.

[0199] Temperature cycling test:

[0200] Set the temperature circulation chamber program: start from room temperature (25℃), and increase the temperature to 120℃ at a rate of 3℃ / minute;

[0201] Keep at 120℃ for 30 minutes;

[0202] Cool to -20°C at a rate of 3°C / minute;

[0203] Keep at -20℃ for 30 minutes;

[0204] Heat to room temperature at a rate of 3℃ / minute;

[0205] The above process constitutes one complete cycle, with a total time of approximately 2 hours;

[0206] The test was repeated 100 times, with a total testing time of approximately 200 hours.

[0207] Performance testing:

[0208] After every 10 cycles, a set of samples was removed from the temperature cycling chamber for the following tests:

[0209] Air permeability test: The oxygen permeability was measured using an air permeability tester according to ASTM D1434-82 standard;

[0210] Surface morphology observation: AFM was used to observe the microstructure of the coating surface and detect the presence of microcracks;

[0211] Dynamic mechanical properties: Storage modulus (E') and loss factor (tanδ) were determined using DMA, with a temperature range of -30°C to 130°C, a heating rate of 2°C / min, and a frequency of 1Hz.

[0212] 1.3 Experimental Results:

[0213] Table 1. Changes in air permeability of samples before and after temperature cycling test

[0214]

[0215] Table 2. Statistics of microcracks on the coating surface after temperature cycling test

[0216] sample <![CDATA[Number of microcracks (number / mm 2 )]]> Average crack length (μm) Average crack width (μm) Sample A 0.2±0.1 1.2±0.5 0.08±0.02 Sample B 32.5±3.8 28.4±6.2 0.95±0.15 Sample C 12.8±2.3 15.6±4.1 0.45±0.12

[0217] Figure 1 The change of energy storage modulus (E') with the number of cycles during temperature cycling is shown.

[0218] 1.4 Conclusion: Through temperature cycling stability testing, the following conclusions can be clearly drawn:

[0219] The air permeability of emulsion sample A of the present invention increased by only 5.2% after 100 temperature cycles, which is much lower than that of control sample B (199.1%) and commercial sample C (91.2%), indicating that it has excellent barrier performance stability.

[0220] The number and size of microcracks on the surface of sample A were significantly lower than those of the control sample, proving that its multi-level cross-linked network structure can effectively prevent the formation of microcracks caused by temperature cycling.

[0221] In terms of dynamic mechanical properties, the storage modulus of sample A decreased by only 1.6%, while that of control sample B and commercially available sample C was 36.8% and 21.3%, respectively, indicating that the mechanical properties of the emulsion of the present invention are more stable under temperature cycling conditions.

[0222] The above results confirm that the multi-level cross-linked network structure of the present invention has excellent temperature cycling adaptability, which is mainly due to the synergistic effect of the different types of cross-linked networks formed by the three functional components.

[0223] 2. Ethanol resistance test

[0224] 2.1 Experimental Objective: To evaluate the immersion stability of the hypercrosslinked fire-retardant fiber ethanol-resistant emulsion of the present invention in ethanol solutions of different concentrations, and to verify its ethanol resistance.

[0225] 2.2 Experimental Materials: The emulsion sample prepared in this embodiment (Sample A); the control sample (Sample B) without the three functional components (acryloyloxy polysilsesquioxane, diallyl dimethylammonium salt, and glycerol dimethacrylate); a commercially available imported ethanol-resistant emulsion (Sample C); a polytetrafluoroethylene mold (100mm × 100mm × 1mm); analytical grade ethanol (99.5%); deionized water; a precision electronic balance (accuracy 0.0001g); a universal testing machine; a microhardness tester; and an infrared spectrometer (ATR mode).

[0226] 2.3 Experimental Procedure:

[0227] Sample preparation:

[0228] Three emulsion samples were poured into polytetrafluoroethylene molds to prepare coatings with a thickness of 1 mm.

[0229] Pre-dry at room temperature for 24 hours, then dry in an oven at 80°C for 2 hours, and finally cure at 120°C for 0.5 hours; cut samples of the following specifications from each coating film:

[0230] For weight determination: 20mm×20mm square plates, 10 of each type;

[0231] For tensile testing: dumbbell-shaped specimens, conforming to GB / T 1040.3-2006 standard, 10 specimens of each type;

[0232] Hardness test: 20mm×20mm square plates, 10 of each type;

[0233] For infrared analysis: 20mm×20mm square plates, 5 of each type of sample.

[0234] Ethanol solution immersion test:

[0235] Prepare aqueous solutions of ethanol at different concentrations: 50%, 75%, and 95% (volume ratio);

[0236] For each concentration, prepare a sufficient number of sealed glass bottles, and add 100 mL of ethanol solution to each bottle;

[0237] Weigh and record the initial weight (W0) of each sample;

[0238] Immerse the sample in an ethanol solution, seal the bottle, and place it in an environment of 23±1℃;

[0239] Samples were taken out and tested at different soaking time points (12h, 24h, 48h, 96h, 7 days);

[0240] After removing the sample, gently wipe away the surface liquid with filter paper, and weigh it after standing at room temperature for 1 hour (W1);

[0241] The sample was then dried in a vacuum oven at 80°C until constant weight, and the weight after drying (W2) was recorded.

[0242] Performance testing:

[0243] Calculation of weight change rate:

[0244] Swelling rate (%) = (W1 - W0) / W0 × 100%;

[0245] Weight loss rate (%) = (W0-W2) / W0 × 100%;

[0246] Tensile property testing: Tensile strength, elongation at break, and modulus of elasticity were determined using a universal testing machine; Hardness testing: Shore D hardness was determined using a microhardness tester.

[0247] Chemical structure analysis: Infrared spectroscopy was used to detect changes in the chemical structure of the samples before and after immersion.

[0248] 2.4 Experimental Results:

[0249] Table 3. Swelling rate (%) after soaking in ethanol solutions of different concentrations for 96 hours

[0250] ethanol concentration Sample A Sample B Sample C 50％ 1.2±0.2 6.8±0.9 3.5±0.5 75％ 1.9±0.3 12.5±1.5 7.2±0.8 95％ 2.8±0.4 24.6±2.2 15.8±1.6

[0251] Table 4. Weight loss rate (%) after soaking in 75% ethanol solution for different times

[0252] Soaking time Sample A Sample B Sample C 12h 0.08±0.02 0.45±0.08 0.25±0.05 24h 0.12±0.03 0.78±0.12 0.42±0.09 48h 0.18±0.03 1.25±0.18 0.68±0.10 96h 0.25±0.04 2.35±0.25 1.05±0.15 7 days 0.32±0.05 3.85±0.35 1.65±0.20

[0253] Table 5. Retention rate of mechanical properties after immersion in 75% ethanol solution for 7 days (%)

[0254] Performance parameters Sample A Sample B Sample C Tensile strength 95.2±1.5 65.8±3.8 78.5±2.6 Elongation at break 91.8±2.2 58.5±4.5 72.3±3.2 elastic modulus 97.5±1.2 72.6±3.5 83.4±2.8 Shore D hardness 98.2±0.8 75.5±3.2 85.2±2.3

[0255] Figure 2 The swelling rate of samples at different ethanol concentrations was compared.

[0256] Figure 3 The changes in the retention rate of tensile strength of the samples during immersion in a 75% ethanol solution are shown.

[0257] 2.5 Conclusion: Based on the ethanol resistance test, the following conclusions can be drawn:

[0258] The emulsion sample A of the present invention exhibited excellent tolerance in ethanol solutions of different concentrations. Even after being soaked in 95% high-concentration ethanol for 96 hours, the swelling rate was only 2.8%, while the control sample B and the commercially available sample C were 24.6% and 15.8%, respectively.

[0259] After prolonged immersion in 75% ethanol solution (7 days), the weight loss rate of sample A was only 0.32%, far lower than that of control sample B (3.85%) and commercially available sample C (1.65%), indicating that its structural stability was significantly improved.

[0260] Sample A maintained excellent mechanical properties after ethanol immersion, with a tensile strength retention rate of 95.2%, while control sample B and commercially available sample C only retained 65.8% and 78.5%, respectively. Other mechanical properties such as elongation at break, elastic modulus, and hardness also showed similar trends.

[0261] Infrared spectroscopy analysis showed that the characteristic peaks of sample A changed very little before and after ethanol immersion, indicating that its chemical structure has excellent stability, which is due to the protective barrier provided by the multi-level cross-linked network structure.

[0262] The above results confirm that the multi-level cross-linked network structure of the present invention can effectively block the penetration of ethanol molecules and prevent ethanol from dissolving and damaging the polymer network, thereby achieving excellent ethanol resistance.

[0263] 3. Damp heat stability test

[0264] 3.1 Experimental objective: To evaluate the stability of the ethanol-resistant emulsion for hypercrosslinked fire-retardant fibers of the present invention under high temperature and high humidity conditions, and to verify its resistance to damp heat.

[0265] 3.2 Experimental Materials: Emulsion sample prepared in this embodiment (Sample A); control sample (Sample B) without the addition of the three functional components (acryloyloxy polysilsesquioxane, diallyl dimethylammonium salt, and glycerol dimethacrylate); commercially available imported ethanol-resistant emulsion (Sample C); aluminum alloy substrate (100mm×100mm×2mm); constant temperature and humidity test chamber (temperature range: 0-150℃, humidity range: 10%-98%RH); contact angle meter; infrared spectrometer (ATR mode); scanning electron microscope (SEM); universal testing machine; electrochemical workstation.

[0266] 3.3 Experimental Procedure:

[0267] Sample preparation:

[0268] Three emulsion samples were coated on aluminum alloy substrates using an automated coating machine, with a wet film thickness of 150 μm.

[0269] Pre-dry at room temperature for 2 hours, then dry in an oven at 80°C for 2 hours, and finally cure at 120°C for 1 hour;

[0270] Fifteen parallel samples were prepared for each emulsion, five of which were used for initial testing and ten for damp heat testing.

[0271] Parameters such as initial contact angle, tensile strength, surface morphology and electrochemical impedance of each sample were measured and recorded.

[0272] Humid and hot environment exposure test:

[0273] Place the sample in a constant temperature and humidity test chamber and set the conditions to 85±1℃ and 85±2%RH.

[0274] Samples were taken and tested at different exposure time points (3 days, 7 days, 15 days, and 30 days).

[0275] After each time point, the sample was taken out and placed at room temperature for 24 hours to equilibrate before various tests were performed.

[0276] Performance testing:

[0277] Contact angle measurement: The contact angle of the water droplet on the sample surface was measured using a contact angle meter. The average value was taken at 5 different locations for each sample.

[0278] Infrared spectroscopy analysis: The chemical structural changes of the samples before and after damp heat exposure were detected using an infrared spectrometer in ATR mode;

[0279] Surface morphology observation: SEM was used to observe the microscopic morphology changes on the coating surface and to detect the presence of cracks, bubbles or signs of degradation.

[0280] Tensile property testing: The change in tensile strength was measured using a universal testing machine;

[0281] Electrochemical impedance spectroscopy (EIS) of the samples was measured using an electrochemical workstation to assess changes in their protective performance.

[0282] 3.4 Experimental Results:

[0283] Table 6. Changes in water contact angle (°) after exposure to a humid and hot environment for different durations.

[0284] Exposure time Sample A Sample B Sample C Day 0 (Initial) 110.5±1.2 108.2±1.5 109.8±1.3 3 days 109.8±1.3 98.5±2.2 104.6±1.8 7 days 108.5±1.5 92.3±2.5 98.7±2.0 15 days 107.2±1.7 85.4±2.8 93.5±2.3 30 days 105.8±1.8 78.6±3.2 89.2±2.5 range of change -4.3％ -27.4％ -18.8％

[0285] Table 7. Performance retention rate (%) after 30 days of exposure to humid and hot environment

[0286] Performance parameters Sample A Sample B Sample C Tensile strength 92.5±1.8 65.3±3.5 77.8±2.4 Elongation at break 90.8±2.0 61.2±3.8 73.5±2.6 rate of change of weight -0.8±0.1 -3.2±0.4 -1.8±0.3 <![CDATA[Electrochemical impedance (10 -2 Hz)]]> 88.5±2.2 58.7±4.0 72.2±3.1

[0287] Table 8. Change rate (%) of characteristic peak intensity of infrared spectrum after 30 days of exposure to a hot and humid environment

[0288] <![CDATA[Characteristic peak (cm -1 )]]> Functional groups Sample A Sample B Sample C 1730-1735 C=O stretching vibration -4.2±0.6 -23.5±2.5 -15.6±1.8 1645-1650 C=N imine bond -5.8±0.8 -32.6±3.0 -21.2±2.2 1050-1080 Si-O-Si bond -2.5±0.5 -12.4±1.8 -8.5±1.2 2850-2950 CH stretching vibration -1.2±0.3 -8.6±1.5 -5.2±1.0

[0289] Figure 4 This demonstrates the change in water contact angle over time during exposure to a humid and hot environment.

[0290] Figure 5 The electrochemical impedance spectroscopy of the samples after 30 days of exposure to a humid and hot environment is shown.

[0291] 3.5 Conclusion: Based on the damp heat stability test, the following conclusions can be drawn:

[0292] In this embodiment, after the emulsion sample A was exposed to a high temperature and high humidity environment (85°C, 85% RH) for 30 days, the water contact angle decreased by only 4.3%, while the control sample B and the commercially available sample C decreased by 27.4% and 18.8%, respectively, indicating that its surface properties have excellent stability under harsh conditions.

[0293] The weight loss rate of sample A was only 0.8%, far lower than that of control sample B (3.2%) and commercially available sample C (1.8%), proving that its structure is more stable in a humid and hot environment and that hydrolysis is significantly reduced.

[0294] Infrared spectroscopy analysis showed that the intensity of the key functional group characteristic peaks of sample A changed little, especially the intensity of the C=O stretching vibration and C=N imine bond peaks, which decreased by only 4.2% and 5.8%, respectively, while the intensity of the control sample B decreased by 23.5% and 32.6%, respectively. This indicates that the multi-level cross-linked network of this embodiment can effectively inhibit the hydrolysis reaction.

[0295] Electrochemical impedance spectroscopy showed that after 30 days of exposure to a humid and hot environment, sample A maintained an impedance retention rate of 88.5% in the low-frequency region (0.01Hz), which was much higher than that of control sample B (58.7%) and commercially available sample C (72.2%), proving that its protective performance was more stable under harsh conditions.

[0296] SEM observation showed that no obvious signs of degradation, such as cracks, bubbles or peeling, were observed on the surface of sample A, while control sample B and commercially available sample C showed different degrees of surface degradation.

[0297] The above results confirm that the multi-level cross-linked network structure of this embodiment has excellent hygrothermal stability, especially the synergistic effect of multiple cross-linking types (covalent cross-linking, ionic cross-linking and reversible cross-linking), which effectively resists the damage of high temperature and high humidity environment.

[0298] The embodiments of the present invention have been described above. However, the embodiments are not limited to the specific implementation methods described above. The specific implementation methods described above are merely illustrative and not restrictive. Those skilled in the art can make more equivalent embodiments under the guidance of the present embodiments, and all of them are within the protection scope of the present embodiments.

Claims

1. An ethanol-resistant emulsion for fire-retardant fibers, characterized in that, By weight, it includes the following components: 350-500 parts water, 15-25 parts SR-10 emulsifier, 10-30 parts diacetone acrylamide, 10-30 parts adipamide, 10-18 parts diallyl phthalate, 1-5 parts trimethylolpropane trimethacrylate, 1-5 parts methacrylic acid, 250-350 parts octyl acrylate, 80-150 parts styrene, 15-35 parts acrylonitrile, 4-10 parts vinyltrimethoxysilane, 1-4 parts ammonium persulfate, 0.5-1.5 parts tert-butyl hydroperoxide, 0.5-1.2 parts sodium D-isoascorbate, 10-15 parts ammonia, and 1-3 parts bactericide.

2. The ethanol-resistant emulsion for fire-retardant fibers according to claim 1, characterized in that, SR-10 emulsifier is a reactive emulsifier containing ammonium groups.

3. The ethanol-resistant emulsion for fire-retardant fibers according to claim 1, characterized in that, A cross-linked structure is formed between diacetone acrylamide and the adipic hydrazide at room temperature.

4. The ethanol-resistant emulsion for fire-retardant fibers according to claim 1, characterized in that, Diallyl phthalate and trimethylolpropane trimethacrylate each contain two or more double bonds, which are used to form a high-temperature cross-linked structure.

5. A method for preparing an ethanol-resistant emulsion for fire-retardant fibers according to any one of claims 1-4, characterized in that, Includes the following steps: Step 1: Preparation of emulsion: Add water, SR-10 emulsifier, diacetone acrylamide, methacrylic acid, acrylonitrile, diallyl phthalate, trimethylolpropane trimethacrylate, styrene, octyl acrylate, vinyltrimethoxysilane, and rinsing water into the emulsion tank in the following order and emulsify for later use. Step 2: Heat the water and emulsifier to 85°C, and add initiator A; Step 3: Simultaneously add emulsion and initiator B. When 1 / 3 of the emulsion remains, add vinyltrimethoxysilane to the emulsion and stir evenly. Then continue to add emulsion and initiator B, keeping the temperature at 84-86°C and the adding time at 3.5 hours. After the addition is complete, add initiator C. Step 4: After the dripping is complete, keep warm at 84-86℃ for 1 hour; Step 5: Cool to 70℃ and add tert-butyl hydrogen peroxide aqueous solution. After 2 minutes, add D-isoascorbic acid sodium aqueous solution. Keep warm for 15 minutes and then vacuum for 30 minutes. Step 6: Cool to 50℃, add adipic hydrazine aqueous solution, stir for 30 minutes, cool to 45℃, adjust the pH value to 7-9 with ammonia water, add bactericide, stir evenly, and then filter out the material.

6. The method for preparing an ethanol-resistant emulsion for fire-retardant fibers according to claim 5, characterized in that, Initiator A, Initiator B, and Initiator C are all aqueous solutions of ammonium persulfate.

7. The method for preparing an ethanol-resistant emulsion for fire-retardant fibers according to claim 5, characterized in that, In step 3, vinyltrimethoxysilane is added in two batches. The first batch accounts for 10%-30% of the total amount, and the second batch accounts for 70%-90% of the total amount.

8. The method for preparing an ethanol-resistant emulsion for fire-retardant fibers according to claim 5, characterized in that, In step 5, tert-butyl hydroperoxide acts as an oxidant, and sodium D-isoascorbate acts as a reducing agent, forming a redox reaction system.

9. The method for preparing an ethanol-resistant emulsion for fire-retardant fibers according to claim 5, characterized in that, In step 6, adipic hydrazide and diacetone acrylamide form a cross-linked structure at room temperature.

10. The ethanol-resistant emulsion for fire-retardant fibers according to claim 1, characterized in that, It also includes acryloyloxy polysilsesquioxane, diallyl dimethylammonium salt, and glycerol dimethacrylate.

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