Outdoor environment-friendly fluoride-free flame-retardant fabric and processing technology thereof

Abstract

The invention relates to the field of flame-retardant fabric preparation, and particularly discloses an outdoor environment-friendly fluoride-free flame-retardant fabric and a processing technology thereof.The flame-retardant fabric comprises a high-weather-resistance fabric layer, a first flame-retardant layer and a second flame-retardant layer; the high-weatherability fabric layer is an acrylic fabric or a polyester fabric subjected to fluoride-free and water-repellent finishing, and a fluoride-free and water-repellent finishing agent comprises one or more of polyurethane, polyacrylic acid and organic silicon; the first flame-retardant layer comprises expandable graphite, ammonium polyphosphate and bonding resin; the second flame-retardant layer comprises one or more of a flame-retardant spunlace non-woven fabric and a flame-retardant TPU (thermoplastic polyurethane) film, at least one surface of the second flame-retardant layer is coated with hot-melt resin slurry dots, and one side coated with the hot-melt resin slurry dots is attached to the first flame-retardant layer.

Description

Technical Field

[0001] This application relates to the field of textile fabrics, and more specifically, to an environmentally friendly, fluorine-free flame-retardant fabric for outdoor use and its processing technology. Background Technology

[0002] With societal progress and improved living standards, people's demands for textiles have become more diversified, and the requirements for functional textiles are increasing. However, this widespread application also leads to frequent fire accidents. According to fire cause analysis, fires caused by textile ignition or spread account for more than 20% of all fire accidents, and more than 50% of deaths are caused by these fires. To effectively reduce the loss of life and property caused by fires, flame-retardant finishing of textiles is imperative. For outdoor textiles, in addition to traditional functions such as weather resistance, UV protection, water repellency, and oil stain resistance, high requirements are placed on their flame-retardant properties. However, most existing outdoor furniture fabrics lack flame retardancy or fail to meet the required standards, hindering their wider application.

[0003] Existing flame-retardant fabrics employ several methods: First, flame-retardant coatings are used to achieve this effect. However, to maximize flame retardancy, halogenated flame retardants and antimony trioxide are commonly used, causing secondary environmental pollution and releasing toxic halogenated gases upon combustion, which can harm the respiratory system. Second, flame-retardant finishing processes are employed to achieve the desired properties. However, fabrics produced using this method often exhibit poor flame retardancy and exhibit limited durability after washing. Third, some fabrics are directly woven from flame-retardant fibers, offering limited color options. These fabrics exhibit poor weather resistance when used outdoors, significantly reducing their lifespan.

[0004] To address the aforementioned issues, it is necessary to develop an outdoor flame-retardant fabric with high weather resistance. This fabric not only possesses excellent weather resistance but also superior flame retardancy and environmental performance. Summary of the Invention

[0005] To improve the flame retardancy and weather resistance of textile fabrics, this application provides an environmentally friendly, fluorine-free flame-retardant fabric for outdoor use and its processing technology.

[0006] In one aspect, this application provides an environmentally friendly, fluorine-free flame-retardant fabric for outdoor use, comprising a highly weather-resistant fabric layer, a first flame-retardant layer, and a second flame-retardant layer; The high weather-resistant fabric layer is an acrylic or polyester fabric treated with a fluorine-free water-repellent finish, wherein the fluorine-free water-repellent finish agent includes one or more of polyurethane, polyacrylic acid, and silicone. The first flame-retardant layer comprises expandable graphite, ammonium polyphosphate, and adhesive resin; The second flame-retardant layer includes one or more of flame-retardant spunlace nonwoven fabric and flame-retardant TPU film. At least one side of the second flame-retardant layer is coated with hot melt resin paste dots, and the side coated with hot melt resin paste dots is bonded to the first flame-retardant layer.

[0007] Preferably, the hot melt resin paste coating step includes: "applying EVA hot melt adhesive to flame-retardant spunlace nonwoven fabric by applying it with an adhesive roller, then laminating it with the fabric, hot pressing it with a pressure roller, and then cooling it", and / or, "applying PUR to flame-retardant TPU film by a roller, then laminating it with the fabric, pressing it with a pressure roller, rolling it up, and leaving it for at least twelve hours".

[0008] This application utilizes a three-layer structure: a fluorine-free water-repellent finish on the fabric base layer, an expandable graphite foam flame-retardant layer, and a second flame-retardant layer for synergistic flame retardancy. The fluorine-free water-repellent finish agent contains no fluorine atoms, avoiding the bioaccumulation of traditional fluorine-containing finishes and meeting environmental protection requirements. Its molecules contain hydrophobic groups, adhering to the fabric surface through physical adsorption and chemical bonds to form a hydrophobic film, achieving water repellency. In the first flame-retardant layer, the expandable graphite decomposes when heated, breaking the interlayer forces and causing a rapid expansion to form a dense carbon layer that blocks oxygen and heat. Ammonium polyphosphate decomposes to produce phosphoric acid, catalyzing the fabric and resin to form carbon, synergistically enhancing flame retardancy with the graphite carbon layer. The flame-retardant fiber or TPU film in the second flame-retardant layer forms a secondary flame-retardant barrier. When the hot-melt resin paste of the second flame-retardant layer is hot-pressed, it melts, and the molecular chains diffuse into the bonding resin of the first flame-retardant layer, forming molecular entanglements. After cooling, physical forces enhance interlayer adhesion, preventing delamination. The resulting fabric combines environmental friendliness, synergistic flame retardancy, and interlayer stability.

[0009] Secondly, this application provides a processing technology for an environmentally friendly, fluorine-free flame-retardant fabric for outdoor use, comprising the following processing steps: S1: Immerse the fabric in a fluorine-free water-repellent finishing agent, soak at room temperature, perform two dips and two nips, pre-dry with heat, bake at higher temperature, and cool to room temperature to obtain a highly weather-resistant fabric layer. S2: Add thickener to deionized water and disperse evenly. Then add acrylic latex, ammonium polyphosphate, and expandable graphite in sequence. Heat and stir to form a uniform and stable flame retardant slurry. Coat the flame retardant slurry evenly onto the high weather-resistant fabric layer, heat and pre-bake, heat and bake, and cool to room temperature to obtain the first flame retardant layer composite high weather-resistant fabric layer intermediate product. S3: The flame-retardant spunlace nonwoven fabric coated with EVA or PUR hot melt resin paste dots is bonded to the above-mentioned fabric, with the paste dot surface facing the first flame-retardant layer, hot-pressed, and cooled to room temperature to obtain an environmentally friendly fluorine-free flame-retardant fabric for outdoor use.

[0010] Preferably, the thickener includes polyacrylic acid thickeners.

[0011] By adopting the above preparation method, fluorine-free waterproofing agent molecules form a continuous hydrophobic film on the surface of polyester fabric. The carboxyl groups in the acrylic latex molecules of the first flame-retardant layer undergo hydrogen bonding with the hydroxyl groups at the edge of the expandable graphite layer and on the surface of ammonium polyphosphate. Simultaneously, some carboxyl groups undergo esterification with the residual hydroxyl groups on the polyester fabric surface to form covalent ester bonds, ensuring the flame-retardant particles firmly adhere to the fabric surface. The double bonds on the acrylic latex molecular chain undergo free radical cross-linking at the baking temperature, forming a three-dimensional network structure, further locking the flame-retardant particles and improving the structural stability of the flame-retardant layer. After the hot-melt resin melts, the vinyl groups in its molecular chain undergo a weak free radical addition reaction with the unreacted double bonds on the acrylic latex molecular chain. Simultaneously, EVA or PUR molecules form hydrogen bonds with the residual active groups in the first flame-retardant layer, achieving a chemical-physical dual bonding between the first and second flame-retardant layers. The molten EVA or PUR resin fills the tiny pores on the surface of the first flame-retardant layer, forming a dense bonding interface after cooling, reducing interlayer voids and further improving the fabric's weather resistance and flame-retardant properties. Expandable graphite layered structures serve as both carbon and gas sources. During combustion, under the influence of an acid source, the layers expand, forming a loose, porous char layer that blocks heat and oxygen transfer. Ammonium polyphosphate acts as the acid source, decomposing to produce phosphoric acid during combustion. Phosphoric acid catalyzes the dehydration and carbonization of polyester and acrylic latex, while simultaneously promoting the decomposition and gas production of intercalation compounds in the expandable graphite layers, further driving graphite expansion. Acrylic latex acts as the bonding resin; the ester and carboxyl bonds in its polyacrylate molecular chains can form chemical and hydrogen bonds with other components, binding flame retardant particles into a film. Simultaneously, it can carbonize itself, enhancing the integrity of the char layer. Ammonium polyacrylate thickeners adjust the slurry viscosity, preventing flame retardant particle sedimentation during coating, ensuring uniform coating thickness, resulting in a denser, more uniform fabric with a more stable flame-retardant effect. EVA or PUR hot-melt resin paste acts as an interlayer adhesive, melting and forming an interfacial bond with the first flame-retardant layer, enhancing interlayer peel strength. Its low-temperature melting characteristics prevent high-temperature damage to the first flame-retardant layer, while its ability to melt and flow during combustion fills gaps in the char layer. The polyester structure of the fabric layer provides mechanical support for the first flame-retardant layer, preventing it from detaching due to its own brittleness. The hydrophobic film on the surface of the fabric layer reduces the erosion of the first flame-retardant layer by moisture, preventing APP from hydrolyzing and failing. At the same time, the hydrophobic film does not affect the air permeability of the flame-retardant layer, further improving the flame-retardant effect. During combustion, the expanded char layer formed by the first flame-retardant layer blocks heat, while the non-woven fiber network of the second flame-retardant layer traps smoke. After the EVA or PUR paste melts, it forms a dense composite layer with the char layer, providing double protection against oxygen and flame. The resulting fabric has excellent weather resistance and dual flame-retardant properties, and is structurally stable and durable.

[0012] Preferably, the first flame-retardant layer comprises the following raw materials in parts by weight: 20-40 parts expandable graphite, 0-10 parts halogen-free flame retardant, 20-40 parts adhesive resin, 0.5-4.0 parts thickener, and 20-40 parts water.

[0013] Preferably, the expandable graphite includes amino-boron bifunctional modified expandable graphite, comprising the following preparation steps: adding expanded graphite to water and dispersing it evenly, adding a phosphoric acid oxidant and ferric chloride, heating and stirring to react, adding sodium borohydride and stirring, adding an intercalating agent, ethylenediamine and boric acid, heating and stirring to react, adjusting the pH, filtering, washing and drying to obtain amino-boron bifunctional modified expandable graphite.

[0014] Oxidation treatment creates voids between the expanded graphite layers, while ethylenediamine introduces amino groups and boron is introduced by boric acid. The amino groups form amide bonds with the binding resin, resolving the agglomeration problem caused by the hydrophobicity of graphite and improving its dispersion uniformity in the slurry. Boron reacts with phosphorus in the APP to form borophosphate glassy substances; the BO bonds are heat-resistant, fill the voids in the carbon layers, enhance the density of the carbon layers, and prevent heat and oxygen transfer. After modification, the interlayer forces of the graphite are weakened, making it easier to expand when heated, further improving flame retardant efficiency.

[0015] Preferably, the acrylic latex comprises the following preparation steps: at room temperature, low molecular weight latex seeds and high molecular weight latex seeds are added to deionized water, sodium dodecylbenzene sulfonate is added, and the mixture is stirred to form a stable seed solution. Styrene, butyl acrylate, acrylic acid, acrylonitrile, hydroxymethylacrylamide, acrylamide, and glycidyl methacrylate are mixed evenly and slowly added dropwise to the seed solution. When 1 / 3 of the solution has been added, ammonium persulfate is added, the temperature is raised, and the remaining monomers are added dropwise. After the addition is complete, the remaining APS is added, the reaction is maintained at the temperature, the temperature is lowered to room temperature, and the mixture is filtered to obtain a copolymer acrylic latex.

[0016] Preferably, low molecular weight latex seeds are 30,000-80,000 Da and high molecular weight latex seeds are 400,000-800,000 Da.

[0017] Preferably, the mass ratio of low molecular weight latex seeds to high molecular weight latex seeds is (3-5):3.

[0018] By employing the above technical solutions, the shorter molecular chains of low-molecular-weight latex allow them to penetrate into the interlayer of modified graphite and react with interlayer -NH2. The longer molecular chains of high-molecular-weight latex form a three-dimensional cross-linked network on the graphite surface, achieving a dual combination of "interlayer penetration + surface encapsulation." The carboxyl groups of acrylic acid may form a small number of amide bonds with the amino groups of modified graphite during subsequent baking, enhancing the interfacial bonding strength. The epoxy groups of GMA may form covalent bonds with boric acid and highly active hydrogen, better introducing boron into the latex network and synergistically catalyzing carbonization. Acrylamide forms hydrogen bonds with water molecules in the graphite interlayer, improving the dispersion compatibility between the latex and graphite. During combustion, the modified graphite expands to form a loose char layer, and the interlayer copolymer latex exhibits a relatively balanced hard and soft segment structure, possessing both strength and flexibility. It softens to a certain extent to form an elastic soft film, which stretches with the deformation of the char layer, filling tiny cracks at the edges of the char layer, preventing oxygen entry and the release of toxic gases, and further enhancing the flame-retardant effect of the resulting fabric by strengthening the gas shielding effect. APP decomposes and reacts with boric acid to generate BPO4 high-temperature resistant ceramic phase, which further enhances the structural stability of the char layer at high temperatures, allowing the fabric to maintain the integrity of the char layer at high temperatures and ensuring stable flame retardant effect.

[0019] Preferably, the EVA hot melt resin slurry includes the following preparation steps: heating EVA resin to melt, adding glycidyl methacrylate and DOPO-acrylic acid, heating to react, cooling, adding microencapsulated red phosphorus, UV-531, antioxidant 1010 and dioctyl terephthalate, stirring, and preparing EVA hot melt resin slurry.

[0020] Preferably, the coverage of the EVA or PUR hot melt resin paste is 20-30% of the area of ​​the first flame retardant layer.

[0021] Preferably, the mass ratio of EVA, glycidyl methacrylate, DOPO-acrylic acid, and dioctyl terephthalate in the EVA hot melt resin slurry is (15-20):(1.5-2.5):(2-3):1.

[0022] By adopting the above technical solution, the epoxy groups in the hot melt resin slurry undergo a ring-opening reaction with the carboxyl groups of the acrylic latex under hot-pressing conditions to generate stable ester bonds. The short chains of low molecular weight acrylic latex can penetrate into the interior of the slurry and react with the internal epoxy groups, while the long chains of high molecular weight acrylic latex form a network at the interface and react with the epoxy groups on the surface of the slurry, further improving the interlayer bonding strength and resulting in better flame retardant effect of the composite fabric.

[0023] Meanwhile, the phosphoric hydroxyl groups in the hot melt resin paste may undergo dehydration condensation with the carboxyl groups of the acrylic latex to form phospholipid bonds, which not only enhances the interlayer bonding, but also decomposes to generate phosphoric acid during combustion. This phosphoric acid, together with the phosphoric acid from the decomposition of APP, catalyzes the carbonization of graphite / latex, forming a denser carbon layer. As a result, the fabric exhibits better performance in flame retardant tests.

[0024] The amino groups on the surface of modified graphite undergo a ring-opening reaction with the unreacted epoxy groups in the slurry dots, better "anchoring" the graphite particles within the slurry dots and preventing graphite from detaching during combustion. The molten modified slurry dots fill the micropores on the surface of the graphite expansion layer, forming a dense "slurry dot-film" composite interface upon cooling. This reduces the permeation channels for oxygen / combustible gases, further enhancing gas shielding. Simultaneously, the MC-RP in the slurry dots forms a "particle-layer" composite structure with the graphite layer, synergistically enhancing the impact resistance of the char layer, preventing cracking, and resulting in a more stable flame-retardant effect.

[0025] In summary, this application has the following beneficial effects: 1. This application achieves flame retardancy by combining a fluorine-free water-repellent finish on the fabric base layer with an expandable graphite foam flame retardant layer and a second flame retardant layer. In the first flame retardant layer, when the expandable graphite is heated, the interlayer intercalator decomposes the dense carbon layer to block oxygen and heat. The second flame retardant layer forms a secondary flame retardant barrier. The interlayer is connected by EVA hot-melt resin paste and fills the gaps in the carbon layer, resulting in a fabric with both high flame retardancy and weather resistance.

[0026] 2. This application defines the composition of the first flame-retardant layer and modifies expandable graphite, prepares special acrylic latex and EVA hot melt resin paste for use together, expandable graphite is uniformly distributed and stably fixed, and the gaps between carbon layers are fully filled by the formed borophosphate glassy substance and elastic soft film, thereby further improving the flame-retardant effect of the obtained fabric by enhancing the gas shielding effect. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the environmentally friendly, fluorine-free flame-retardant fabric for outdoor use prepared in this application.

[0028] Explanation of reference numerals in the attached figures: 1. Second flame-retardant layer; 2. First flame-retardant layer; 3. High weather-resistant fabric layer. Detailed Implementation

[0029] To further aid in understanding the technical solution of this invention, several specific implementation examples are provided below to describe the technical solution of this invention in more detail. All of these described embodiments are only some embodiments of this invention, and not all of them. The following specific embodiments can be combined with each other. The same or similar concepts or processes may not be described again in some embodiments. Unless otherwise specified, the reaction devices, monomer compounds and other materials involved in the following embodiments are commercially available.

[0030] The following examples are further illustrations of the present invention, but the present invention is not limited thereto.

[0031] Flame-retardant spunlace nonwoven fabric was purchased from Changzhou Huana Nonwoven Fabric Co., Ltd., aramid fiber wear-resistant, fire-retardant spunlace nonwoven fabric, item number 024; solution-dyed acrylic fabric was Glen Raven solution-dyed acrylic fabric; fluorine-free water-repellent finishing agent was purchased from Suzhou Jiesheng New Material Technology Co., Ltd., fluorine-free waterproof agent ZC-7805; expandable graphite was purchased from Qingdao Mingrun Chenyue Graphite Co., Ltd., 9580250; EVA resin (VA content 28%, melting point 140℃); microencapsulated red phosphorus was purchased from Meimao New Material MM-F3; commercially available acrylic latex was purchased from Zeon Nipol LX851F2; commercially available EVA was purchased from Mitsui Chemicals EV40W; thickener was purchased from Transfar Group Co., Ltd., environmentally friendly thickener TF-312F.

[0032] Preparation Example 1: Amino-boron bifunctional modified expandable graphite Add 42g of expanded graphite to 85ml of water and disperse evenly. Add 9g of silver phosphate and 2g of ferric chloride. Heat and stir at 45℃ for 35 minutes. Add 1g of sodium borohydride and continue stirring for 10 minutes. Add 23g of ferric chloride, 7g of ethylenediamine and 5g of boric acid. Heat to 50℃ and stir for 90 minutes. Adjust the pH to 5-6. Filter, wash and dry to obtain amino-boron bifunctional modified expandable graphite.

[0033] Preparation Example 2: Amine-modified expandable graphite Add 42g of expanded graphite to 85ml of water and disperse evenly. Add 9g of silver phosphate and 2g of ferric chloride. Heat and stir at 45℃ for 35 minutes. Add 1g of sodium borohydride and continue stirring for 10 minutes. Add 23g of ferric chloride and 12g of ethylenediamine. Heat to 50℃ and stir for 90 minutes. Adjust the pH to 5-6. Filter, wash, and dry to obtain amino-modified expandable graphite.

[0034] Preparation Example 3: Boron-modified expandable graphite Add 42g of expanded graphite to 85ml of water and disperse evenly. Add 9g of silver phosphate and 2g of ferric chloride. Heat and stir at 45℃ for 35 minutes. Add 1g of sodium borohydride and continue stirring for 10 minutes. Add 23g of ferric chloride and 12g of boric acid. Heat to 50℃ and stir for 90 minutes. Adjust the pH to 5-6. Filter, wash, and dry to obtain boron-modified expandable graphite.

[0035] Preparation Example 4: Acrylic Latex: Preparation of low molecular weight latex seeds: Mix 48 ml of deionized water, 1.5 g of sodium dodecyl sulfate, and 0.5 g of polyoxyethylene octylphenol ether until homogeneous. Slowly add 4 g of styrene, 26 g of butyl acrylate, and 3 g of acrylic acid. Continue stirring for 30 minutes. Heat to 82±1℃ and hold at that temperature for 10 minutes. Weigh 0.8 g of ammonium persulfate and dissolve it in 5 mL of deionized water to obtain an ammonium persulfate aqueous solution. Slowly add the solution dropwise to a flask over 15 minutes. Then keep the solution at that temperature for 2 hours, cool it down to 75℃, keep it at that temperature for 1 hour, and then cool it down to below 40℃. Adjust the pH to 7.0-7.5 with ammonia water. Filter the solution through a 200-mesh screen to obtain low molecular weight latex seeds.

[0036] Preparation of high molecular weight latex seeds: Mix 48 ml of deionized water, 1.2 g of sodium dodecyl sulfate, and 0.4 g of polyoxyethylene octylphenol ether until homogeneous. Slowly add 15 g of styrene, 15 g of butyl acrylate, and 2 g of acrylic acid. Continue stirring for 40 minutes. Heat to 76 ± 1 °C and hold at that temperature for 15 minutes. Weigh 0.28 g of ammonium persulfate and dissolve it in 5 mL of deionized water to obtain an ammonium persulfate aqueous solution. Slowly add the solution dropwise to a flask over 15 minutes. Then keep the solution at that temperature for 3 hours. Heat to 80 °C and keep at that temperature for 1.5 hours. Cool to below 40 °C and adjust the pH to 7.0-7.5 with ammonia. Filter the solution through a 200-mesh screen to obtain high molecular weight latex seeds.

[0037] Preparation of acrylic latex: At room temperature, 35g of high molecular weight latex seeds were added to 80ml of deionized water, along with 1.2g of sodium dodecylbenzenesulfonate. The mixture was stirred to form a stable seed solution. 7g of styrene, 38g of butyl acrylate, 8g of acrylic acid, 5g of acrylamide, 4g of acrylonitrile, 3g of hydroxymethylacrylamide, and 2g of glycidyl methacrylate were mixed evenly and slowly added dropwise to the seed solution. When 1 / 3 of the solution was added, 0.4g of ammonium persulfate was added, the temperature was raised, and the remaining monomers were added dropwise. After the addition was complete, another 0.4g of ammonium persulfate was added. The mixture was kept at 75℃ for 60 minutes, cooled to room temperature, and filtered through a 100-mesh filter to obtain a copolymer acrylic latex.

[0038] Preparation Example 5: Acrylic Latex: At room temperature, 15g of high molecular weight latex seeds and 20g of low molecular weight latex seeds prepared in Example 4 were added to 80ml of deionized water, and 1.2g of sodium dodecylbenzenesulfonate was added. The mixture was stirred to form a stable seed solution. 7g of styrene, 38g of butyl acrylate, 8g of acrylic acid, 5g of acrylamide, 4g of acrylonitrile, 3g of hydroxymethylacrylamide, and 2g of glycidyl methacrylate were mixed evenly and slowly added dropwise to the seed solution. When 1 / 3 of the solution was added, 0.4g of ammonium persulfate was added, the temperature was raised, and the remaining monomers were added dropwise. After the addition was complete, 0.4g of ammonium persulfate was added again. The mixture was kept at 75℃ for 60 minutes, cooled to room temperature, and filtered through a 100-mesh filter to obtain a copolymer acrylic latex.

[0039] Preparation Example 6: Acrylic Latex: At room temperature, 20g of high molecular weight latex seeds and 15g of low molecular weight latex seeds prepared in Example 4 were added to 80ml of deionized water, and 1.2g of sodium dodecylbenzenesulfonate was added. The mixture was stirred to form a stable seed solution. 7g of styrene, 38g of butyl acrylate, 8g of acrylic acid, 5g of acrylamide, 4g of acrylonitrile, 3g of hydroxymethylacrylamide, and 2g of glycidyl methacrylate were mixed evenly and slowly added dropwise to the seed solution. When 1 / 3 of the solution was added, 0.4g of ammonium persulfate was added, the temperature was raised, and the remaining monomers were added dropwise. After the addition was complete, 0.4g of ammonium persulfate was added again. The mixture was kept at 75℃ for 60 minutes, cooled to room temperature, and filtered through a 100-mesh filter to obtain a copolymer acrylic latex.

[0040] Preparation Example 7: EVA hot melt resin paste: 60g of EVA resin was heated to 160℃ to melt, 8g of glycidyl methacrylate and 10g of DOPO-acrylic acid were added, the temperature was raised to 170℃ and reacted for 30 minutes, the temperature was lowered to 150℃, 15g of microencapsulated red phosphorus, 0.5g of UV-531, 0.3g of antioxidant 1010 and 4g of dioctyl terephthalate were added, and the mixture was stirred at 150℃ for 10 minutes to prepare EVA hot melt resin slurry.

[0041] Preparation Example 8: EVA hot melt resin paste: 50g of EVA resin was heated to 160℃ to melt, 18g of glycidyl methacrylate and 10g of DOPO-acrylic acid were added, the temperature was raised to 170℃ and reacted for 30 minutes, the temperature was lowered to 150℃, 15g of microencapsulated red phosphorus, 0.5g of UV-531, 0.3g of antioxidant 1010 and 4g of dioctyl terephthalate were added, and the mixture was stirred at 150℃ for 10 minutes to prepare EVA hot melt resin slurry. Example

[0042] Example 1 S1: Immerse the solution-dyed acrylic fabric in a commercially available fluorine-free water-repellent finishing agent at a liquor ratio of 1:20, soak at room temperature, perform two dips and two nips, with a nip-out rate of 60%, pre-dry at 125°C for 2.5 minutes, bake at 165°C for 4 minutes, and cool to room temperature to obtain a highly weather-resistant fabric layer. S2: Add 1.5g of thickener to 25ml of deionized water and disperse evenly. Then add 35g of acrylic latex prepared in Preparation Example 4, 6g of ammonium polyphosphate, 32g of expandable graphite, and 1g of thickener in sequence. Heat to 40℃ and stir to form a uniform and stable flame-retardant slurry. Coat the flame-retardant slurry evenly on the high weather-resistant fabric layer, pre-bake at 65℃ for 8 minutes, bake at 135℃ for 7 minutes, and cool to room temperature to obtain the first flame-retardant layer composite high weather-resistant fabric layer intermediate product. S3: The flame-retardant polyester spunlace nonwoven fabric coated with the EVA hot-melt resin paste dots prepared in Example 7 is laminated with the above-mentioned fabric. The EVA hot-melt resin paste coverage is 22%, and the paste dot surface faces the first flame-retardant layer. The fabric is then laminated with the fabric, hot-pressed with a pressure roller, and then hot-pressed at 140°C and 0.35MPa for 25s. After cooling to room temperature, an environmentally friendly fluorine-free flame-retardant fabric for outdoor use is obtained.

[0043] Example 2 The only difference between this embodiment and Example 1 is that the expandable graphite is the amino-boron bifunctional modified expandable graphite prepared in Example 1.

[0044] Example 3 The only difference between this embodiment and Example 1 is that the expandable graphite is the amino-modified expandable graphite obtained in Preparation Example 2.

[0045] Example 4 The only difference between this embodiment and Example 1 is that the expandable graphite is the boron-modified expandable graphite prepared in Example 3.

[0046] Example 5 The only difference between this embodiment and Example 2 is that the acrylic latex was prepared in Example 5.

[0047] Example 6 The only difference between this embodiment and Example 2 is that the acrylic latex was prepared in Example 6.

[0048] Example 7 The only difference between this embodiment and Example 2 is that the EVA hot melt resin slurry was prepared in Example 8.

[0049] Comparative Example Comparative Example 1 S1: Immerse the solution-dyed acrylic fabric in a commercially available fluorine-free water-repellent finishing agent at a liquor ratio of 1:20, soak at room temperature, perform two dips and two nips, with a nip-out rate of 60%, pre-dry at 125°C for 2.5 minutes, bake at 165°C for 4 minutes, and cool to room temperature to obtain a highly weather-resistant fabric layer. S2: Add 1.5g thickener to 25ml deionized water and disperse evenly. Then add 35g commercially available acrylic latex, 6g ammonium polyphosphate, 32g expandable graphite, and 1g thickener in sequence. Heat to 40℃ and stir to form a uniform and stable flame-retardant slurry. Coat the flame-retardant slurry evenly onto the high weather-resistant fabric layer, pre-bake at 65℃ for 8 minutes, bake at 135℃ for 7 minutes, and cool to room temperature to obtain the first flame-retardant layer composite high weather-resistant fabric layer intermediate product. S3: The flame-retardant polyester spunlace nonwoven fabric coated with the EVA hot-melt resin paste dots prepared in Example 7 is laminated with the above-mentioned fabric. The EVA hot-melt resin paste coverage is 22%, and the paste dot surface faces the first flame-retardant layer. The fabric is then laminated with the fabric, hot-pressed with a pressure roller, and then hot-pressed at 140°C and 0.35MPa for 25s. After cooling to room temperature, an environmentally friendly fluorine-free flame-retardant fabric for outdoor use is obtained.

[0050] Comparative Example 2 S1: Immerse the solution-dyed acrylic fabric in a commercially available fluorine-free water-repellent finishing agent at a liquor ratio of 1:20, soak at room temperature, perform two dips and two nips, with a nip-out rate of 60%, pre-dry at 125°C for 2.5 minutes, bake at 165°C for 4 minutes, and cool to room temperature to obtain a highly weather-resistant fabric layer. S2: Add 1.5g of thickener to 25ml of deionized water and disperse evenly. Then add 35g of acrylic latex prepared in Preparation Example 4, 6g of ammonium polyphosphate, 32g of expandable graphite, and 1g of thickener in sequence. Heat to 40℃ and stir to form a uniform and stable flame-retardant slurry. Coat the flame-retardant slurry evenly on the high weather-resistant fabric layer, pre-bake at 65℃ for 8 minutes, bake at 135℃ for 7 minutes, and cool to room temperature to obtain the first flame-retardant layer composite high weather-resistant fabric layer intermediate product. S3: The flame-retardant polyester spunlace nonwoven fabric coated with commercially available EVA hot melt resin paste dots is laminated with the above-mentioned fabric. The EVA hot melt resin paste coverage is 22%, and the paste dots face the first flame-retardant layer. The fabric is then laminated with the fabric, hot-pressed with a pressure roller, and then hot-pressed at 140°C and 0.35MPa for 25s. After cooling to room temperature, an environmentally friendly, fluorine-free flame-retardant fabric for outdoor use is obtained.

[0051] Comparative Example 3 S1: Immerse the solution-dyed acrylic fabric in a commercially available fluorine-free water-repellent finishing agent at a liquor ratio of 1:20, soak at room temperature, perform two dips and two nips, with a nip-out rate of 60%, pre-dry at 125°C for 2.5 minutes, bake at 165°C for 4 minutes, and cool to room temperature to obtain a highly weather-resistant fabric layer. S2: Add 1.5g of thickener to 25ml of deionized water and disperse evenly. Then add 35g of acrylic latex prepared in Preparation Example 4, 6g of ammonium polyphosphate, 32g of expandable graphite, and 1g of thickener in sequence. Heat to 40℃ and stir to form a uniform and stable flame-retardant slurry. Coat the flame-retardant slurry evenly on the high weather-resistant fabric layer, pre-bake at 65℃ for 8 minutes, bake at 135℃ for 7 minutes, and cool to room temperature to obtain the first flame-retardant layer composite high weather-resistant fabric layer intermediate product. S3: Repeat S2, and apply flame retardant paste again to the side of the intermediate product flame retardant paste in the first flame retardant layer composite high weather-resistant fabric layer. Pre-bake at 65℃ for 8 minutes, bake at 135℃ for 7 minutes, and cool to room temperature to obtain an outdoor environmentally friendly fluorine-free flame retardant fabric.

[0052] Performance testing I. Performance of the product in Example 1: (1) Flame retardant performance: Passes the BS5852 flame retardant test (fire source 1, simulated match), 25℃, 50%RH, and meets the performance requirements of GB8624-2012 building materials B1 grade.

[0053] (2) Weather resistance: The test method is SAEJ2527, with exposure to 1500KJ / m². 2 Afterwards, the color fastness rating for weathering is ≥4.5 (5 is the best, 1 is the worst); the strength loss is ≤25%.

[0054] (3) UV protection performance: UPF value > 50, UV-A transmittance < 5%, which is a UV protection product.

[0055] (4) Spray resistance: The spray test score is above 80.

[0056] II. All examples and comparative examples were tested for afterflame time and damage length according to GB / T5455-2014; 0.35 W / m was observed at a Daylight filter and a wavelength of 340 nm. 2 Simulated sunlight, blackboard temperature 65±3℃ to simulate sun exposure, relative humidity 50±5%, 18min spraying / 102min drying (simulated rainfall), 200 cycles for outdoor aging, then repeated damage length test to obtain the damage length after aging.

[0057] The test results are shown in Table 1.

[0058] Table 1 Afterburn time (s) Damaged length (mm) Length of damage after aging (mm) Example 1 2.4 14.3 19.1 Example 2 0 5.6 10.8 Example 3 1.1 10.9 14.1 Example 4 1.5 12.6 16.8 Example 5 0 4.6 5.6 Example 6 0 4.9 8.6 Example 7 1.8 12.3 15.4 Comparative Example 1 4.8 24.7 30.4 Comparative Example 2 3.6 22.3 33.6 Comparative Example 3 5.6 35.1 48.2 In conjunction with Example 1, Comparative Examples 1-3 and Table 1, this application achieves flame retardancy by adding a fluorine-free water-repellent finish to the fabric base layer, along with an expandable graphite foam flame-retardant layer and a second flame-retardant layer. In the first flame-retardant layer, when the expandable graphite is heated, the interlayer intercalator decomposes the dense carbon layer to block oxygen and heat. The second flame-retardant layer forms a secondary flame-retardant barrier. The interlayers are connected by EVA hot-melt resin paste and fill the gaps in the carbon layer, resulting in a fabric with both high flame retardancy and weather resistance.

[0059] In conjunction with Examples 1-4 and Table 1, this application further improves the performance of the product by modifying amino-boron bifunctional expandable graphite.

[0060] In conjunction with Examples 2, 5-6 and Table 1, this application demonstrates that acrylic latex prepared by using a certain mass ratio of high and low molecular weight latex seeds can better coat the carbon layer edge and form a gas barrier, thereby further improving the performance of the product.

[0061] In conjunction with Examples 2 and 7 and Table 1, this application achieves better entanglement and interfacial bonding by limiting the preparation process of the hot melt paste and limiting the monomer ratio, resulting in products that are flame-retardant and weather-resistant for a long time.

[0062] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. An environmentally friendly, fluorine-free flame-retardant fabric for outdoor use, characterized in that: It includes a high weather-resistant fabric layer, a first flame-retardant layer, and a second flame-retardant layer; The high weather-resistant fabric layer is an acrylic or polyester fabric treated with a fluorine-free water-repellent finish, wherein the fluorine-free water-repellent finish agent includes one or more of polyurethane, polyacrylic acid, and silicone. The first flame-retardant layer comprises expandable graphite, ammonium polyphosphate, and adhesive resin; The second flame-retardant layer includes one or more of flame-retardant spunlace nonwoven fabric and flame-retardant TPU film. At least one side of the second flame-retardant layer is coated with hot melt resin paste dots, and the side coated with hot melt resin paste dots is bonded to the first flame-retardant layer.

2. A processing method for an outdoor environmentally friendly fluorine-free flame-retardant fabric according to claim 1, characterized in that: The processing steps include the following: S1: Immerse the fabric in a fluorine-free water-repellent finishing agent, soak at room temperature, perform two dips and two nips, pre-dry with heat, bake at higher temperature, and cool to room temperature to obtain a highly weather-resistant fabric layer. S2: Add thickener to deionized water and disperse evenly. Then add acrylic latex, ammonium polyphosphate, and expandable graphite in sequence. Heat and stir to form a uniform and stable flame retardant slurry. Coat the flame retardant slurry evenly onto the high weather-resistant fabric layer, heat and pre-bake, heat and bake, and cool to room temperature to obtain the first flame retardant layer composite high weather-resistant fabric layer intermediate product. S3: The flame-retardant spunlace nonwoven fabric coated with EVA or PUR hot melt resin paste dots is bonded to the above-mentioned fabric, with the paste dot surface facing the first flame-retardant layer, hot-pressed, and cooled to room temperature to obtain an environmentally friendly fluorine-free flame-retardant fabric for outdoor use.

3. The processing technology of an outdoor environmentally friendly fluorine-free flame-retardant fabric according to claim 2, characterized in that: The first flame-retardant layer comprises the following raw materials in parts by weight: 20-40 parts expandable graphite, 0-10 parts halogen-free flame retardant, 20-40 parts adhesive resin, 0.5-4.0 parts thickener, and 20-40 parts water.

4. The processing technology of an outdoor environmentally friendly fluorine-free flame-retardant fabric according to claim 3, characterized in that: The expandable graphite includes amino-boron bifunctional modified expandable graphite, which includes the following preparation steps: adding expanded graphite to water and dispersing it evenly, adding a phosphoric acid oxidant and ferric chloride, heating and stirring to react, adding sodium borohydride and stirring, adding an intercalating agent, ethylenediamine and boric acid, heating and stirring to react, adjusting the pH, filtering, washing and drying to obtain amino-boron bifunctional modified expandable graphite.

5. The processing technology of an outdoor environmentally friendly fluorine-free flame-retardant fabric according to claim 2, characterized in that: The acrylic latex comprises the following preparation steps: at room temperature, low molecular weight latex seeds and high molecular weight latex seeds are added to deionized water, sodium dodecylbenzene sulfonate is added, and the mixture is stirred to form a stable seed solution. Styrene, butyl acrylate, acrylic acid, acrylonitrile, hydroxymethylacrylamide, acrylamide, and glycidyl methacrylate are mixed evenly and slowly added dropwise to the seed solution. When 1 / 3 of the solution is added, ammonium persulfate is added, the temperature is raised, and the remaining monomers are added dropwise. After the addition is complete, the remaining APS is added, the reaction is maintained at the temperature, the temperature is lowered to room temperature, and the mixture is filtered to obtain a copolymer acrylic latex.

6. The processing technology of an outdoor environmentally friendly fluorine-free flame-retardant fabric according to claim 5, characterized in that: The low molecular weight latex seeds have a molecular weight of 30,000-80,000 Da and the high molecular weight latex seeds have a molecular weight of 400,000-800,000 Da.

7. The processing technology of an outdoor environmentally friendly fluorine-free flame-retardant fabric according to claim 5, characterized in that: The mass ratio of the low molecular weight latex seeds to the high molecular weight latex seeds is (3-5):

3.

8. The processing technology of an outdoor environmentally friendly fluorine-free flame-retardant fabric according to claim 2, characterized in that: The EVA hot melt resin slurry includes the following preparation steps: heating EVA resin to melt, adding glycidyl methacrylate and DOPO-acrylic acid, heating to react, cooling, adding microencapsulated red phosphorus, UV-531, antioxidant 1010 and dioctyl terephthalate, stirring, and preparing EVA hot melt resin slurry.

9. The processing technology of an outdoor environmentally friendly fluorine-free flame-retardant fabric according to claim 2, characterized in that: The coverage of the EVA or PUR hot melt resin paste is 20-30% of the area of ​​the first flame retardant layer.

10. The processing technology of an outdoor environmentally friendly fluorine-free flame-retardant fabric according to claim 8, characterized in that: The mass ratio of EVA, glycidyl methacrylate, DOPO-acrylic acid, and dioctyl terephthalate in the EVA hot melt resin slurry is (15-20):(1.5-2.5):(2-3):1.

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