Heat-insulation fireproof protective clothing and preparation method thereof

Abstract

The invention discloses a heat-insulating fireproof protective garment and a preparation method thereof, and belongs to the technical field of fire-fighting composite fabrics. The preparation method comprises the following steps: firstly, carrying out surface modification on montmorillonoid by adopting amino silane, and then carrying out bonding reaction on phosphate ester compounds and the montmorillonoid to form modified montmorillonoid firmly anchored with a flame-retardant component; then the modified montmorillonite, polyester chips and melamine polyphosphate are blended and spun to prepare modified polyester fibers, and the modified polyester fibers and basalt fibers are blended and woven into a fireproof layer; finally, the fireproof layer, the aerogel felt heat insulation layer and the cotton / aramid fiber 1414 blended skin-friendly layer are sewn through aramid fiber sewing threads. Compared with the prior art, by means of the molecular-level interface bonding and skeleton enhancing technology, a compact and stable carbon layer is formed when the protective clothing is burnt, the flame-retardant durability and the thermal protection performance are remarkably improved, and meanwhile light weight and wearing comfort are considered.

Description

Technical Field

[0001] This invention relates to the field of fire-resistant composite fabric technology, and in particular to a heat-insulating and fire-resistant protective suit and its preparation method. Background Technology

[0002] As crucial equipment for protecting the lives of firefighters, the technological development of fire-fighting protective clothing has always revolved around improving its heat insulation, flame retardancy, and wearing comfort. Existing technologies primarily achieve protective functions through multi-layered composite structures. For example, patent application publication number CN109733013A employs a three-layer structure of fire-retardant fiber fabric, bamboo fiber fabric, and a nylon-cotton blend. While it possesses some moisture-wicking and breathability, its flame-retardant layer mainly relies on the inherent properties of the flame-retardant fibers themselves, lacking an efficient flame-retardant synergistic system. Under sustained high temperatures, its protective performance significantly deteriorates. Patent application publication number CN117465088A constructs a multi-layered heat insulation system using pre-oxidized polyacrylonitrile fibers, ceramic fibers, and an aerogel coating. While this improves short-term heat resistance, the flame retardant and fiber matrix are mostly physically mixed, making performance prone to degradation after repeated use or washing. Another patent application, CN120269888A, uses coated modified ammonium polyphosphate as a flame retardant. The core-shell structure improves its compatibility with polymers. However, this structure is prone to coating layer rupture under extreme thermal shock, resulting in the rapid release of flame retardant components and the inability to form a stable char layer protective barrier.

[0003] A comprehensive analysis of existing technologies reveals the following common shortcomings in current fire-fighting protective clothing: First, flame-retardant systems often rely on physical blending or simple coating techniques, resulting in weak interfacial bonding between the flame-retardant components and the matrix material. This makes them prone to migration and loss during use, leading to insufficient protective durability. Second, the char layer formed under high-temperature conditions exhibits low strength and poor continuity, failing to effectively resist flame penetration and thermal shock. Third, the pursuit of protective performance often employs heavy, multi-layered designs, sacrificing flexibility and wearing comfort. Therefore, there is an urgent need to develop a novel protective clothing manufacturing technology that can achieve secure anchoring of flame-retardant components, stable and enhanced char layer structure, while also considering lightweight and durability. Summary of the Invention

[0004] In view of the problems of easy migration of flame retardant components, poor stability of char layer and insufficient protective durability in existing technologies, this invention aims to provide a heat-insulating and fireproof protective clothing with long-lasting flame retardant performance, high thermal protection efficiency and lightweight through molecular-level interface bonding and skeleton reinforcement technology, as well as its preparation method.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: A method for preparing a heat-insulating and fire-resistant protective suit is as follows: The fireproof layer, heat insulation layer, and skin-friendly layer are sewn together with sewing thread from the outside to the inside to obtain the heat-insulating and fireproof protective clothing. The method for preparing the fireproof layer is as follows: Step 1: Dissolve aminosilane in an aqueous ethanol solution, stir and adjust the pH of the solution to acidic to obtain a silane solution; immerse montmorillonite in the silane solution, stir under heating conditions, separate the solid after completion, wash and dry to obtain pretreated montmorillonite; add the pretreated montmorillonite to an aqueous solution of a phosphate ester compound, adjust the pH of the reaction system to acidic, stir under heating conditions, separate, wash and dry after completion to obtain modified montmorillonite; Step 2: Mix polyester chips, melamine polyphosphate and the modified montmorillonite in a certain proportion, and then melt-extrude and granulate to obtain modified polyester masterbatch; mix the modified polyester masterbatch with polyester chips in a certain proportion and then spin to obtain modified polyester fiber; blend the modified polyester fiber with basalt fiber in a certain proportion to form yarn, and then weave to obtain the fireproof layer.

[0006] Preferably, the fireproof layer is prepared by the following method: Step 1: Dissolve aminosilane in a 60-80 wt% aqueous ethanol solution and stir thoroughly until homogeneous. Then, adjust the pH of the solution to 4-5 with acetic acid to obtain a silane solution. Immerse montmorillonite in the prepared silane solution at a solid-liquid ratio of 0.5-2 g: 4-8 mL. Stir continuously for 1-5 hours at a constant temperature of 70-80℃. After stirring, separate the solid, wash with anhydrous ethanol 1-3 times, and then dry to obtain pretreated montmorillonite. Add the pretreated montmorillonite to a 3-7 wt% aqueous solution of phosphate ester compound at a solid-liquid ratio of 0.5-2 g: 5-15 mL. Then, adjust the pH of the reaction system to 1.5-3 with 0.05-0.2 mol / L hydrochloric acid and stir continuously at 75-80℃ for 5-10 hours. After stirring, cool naturally to room temperature, centrifuge, wash repeatedly with water until the filtrate is neutral, and dry to obtain modified montmorillonite. Step 2: Mix polyester chips, melamine polyphosphate, and modified montmorillonite evenly at a mass ratio of 40-50:2-5:1-3, and extrude and granulate the mixture using a conventional extrusion process with a twin-screw extruder to obtain modified polyester masterbatch. Mix the modified polyester masterbatch with polyester chips at a mass ratio of 0.5-2:3-5 and spin the mixture using a conventional spinning process to obtain modified polyester fibers. Blend the modified polyester fibers with basalt fibers at a mass ratio of 6-12:0.5-2 to form yarn, and then weave the yarn in plain weave to obtain a fireproof layer. The heat insulation layer is an aerogel felt; The skin-friendly layer is a blend of cotton fiber and aramid 1414 at a mass ratio of 5-10:1-5, woven in a plain weave, with a weight of 150-200 g / m². 2 ; The stitch density of the sewing thread is 4-5 stitches / cm.

[0007] In step 1, aminosilane is dissolved in a 60-80 wt% aqueous ethanol solution at a solid-liquid ratio of 0.5-2 g: 8-15 mL.

[0008] The aminosilane is at least one of γ-aminopropyltrimethoxysilane and N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane.

[0009] The phosphate ester compound is at least one of dimethyl methylphosphonate, dimethyl-vinyl phosphate, and dimethyl 2-hydroxyethylphosphonate.

[0010] The fireproof layer has a basis weight of 200-300 g / m³. 2 .

[0011] The design concept of this invention stems from a systematic improvement on the shortcomings of existing protective clothing materials in terms of high-temperature protection durability, structural stability, and thermal management efficiency. By constructing a multi-level synergistic protection mechanism of molecular bonding, interface reinforcement, and macroscopic composite, it innovatively combines chemically modified inorganic fillers with a high-performance fiber skeleton, achieving a balance between flame retardancy, thermal insulation, and structural integrity. Specifically, firstly, at the molecular level, a directional reaction pathway between aminosilane and phosphate ester is designed, allowing the flame-retardant component to be firmly anchored to the montmorillonite carrier through covalent bonds; subsequently, at the material construction level, a basalt fiber network is introduced as a heat-resistant skeleton, forming a stable three-dimensional protective system; finally, an aerogel insulation layer and a comfort layer are integrated through lamination composite technology, achieving multi-level dissipation and barrier against thermal threats.

[0012] Compared with existing technologies, it has the following advantages: 1) This invention constructs an organic-inorganic composite heat-resistant skeleton, enabling the fabric to form a continuous, dense, and mechanically strong stable char layer under extreme high temperatures. This char layer effectively resists flame impact and mechanical forces, significantly reducing the risk of heat penetration caused by char layer cracking and pulverization, thus providing wearers with more reliable safety protection.

[0013] 2) This invention is based on a synergistic flame-retardant system constructed with strong chemical bonds, which can form a highly efficient heat insulation barrier during combustion. This barrier can greatly slow down the rate of heat transfer to the interior of the protective clothing, thereby significantly extending the safe time for the back to reach the critical temperature, providing a longer emergency response window for operations in high-temperature environments.

[0014] 3) This invention uses molecular design to firmly anchor the flame-retardant components to the carrier via covalent bonds, fundamentally solving the problem of migration and loss of traditional flame retardants. This ensures that the flame-retardant and heat-insulating properties of the protective clothing remain stable after multiple uses or washes, improving the product's lifespan and protective reliability. Detailed Implementation

[0015] Main source of materials: Aerogel felt, thickness: 9mm, elongation at break: 0.61%, compressive strength: 78MPa, service temperature: -200℃-966℃, thermal conductivity: 0.02-0.62W / (m·K), fire resistance temperature: 627℃, low-temperature bending strength: ≤0.67, water repellency ≥98.43%, density: 160-196kg / m³ 3 Tensile strength ≤236MPa, closed cell rate >77%, flexural strength: 51MPa, compressive strength: 4~19.8MPa, application: textile industry.

[0016] Montmorillonite, mesh size: 325 mesh, active ingredient content: 90%, pH value: 8, whiteness: 90%, water content: 0.1%, apparent viscosity: 8 mPa·s.

[0017] Aramid sewing thread, specification: 400D / 3, thread diameter: 0.35mm, Guangdong Weiwoke Weaving Co., Ltd.

[0018] Polyester chips, grade: CR-8863, manufacturer: Changzhou Huarun.

[0019] Melamine polyphosphate, item number: 003, Dongguan Xingyuan Chemical Co., Ltd.

[0020] Aramid 1414, linear density: 1.5D, length: 51mm, weight: 280g / m² 2 .

[0021] Basalt fiber, length: 25mm, tensile strength >1050MPa, tensile elongation <3.5%, diameter range: 20um.

[0022] N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, CAS No.: 1760-24-3, Molecular Formula: C8H 22 N2O3Si.

[0023] All other raw materials used in the embodiments and comparative examples of this invention are commercially available products.

[0024] Example 1 A method for preparing a heat-insulating and fire-resistant protective suit is as follows: The fireproof layer, heat insulation layer, and skin-friendly layer are sewn together from the outside to the inside using aramid thread at a stitch density of 5 stitches / cm to obtain the heat-insulating and fireproof protective clothing. The method for preparing the fireproof layer is as follows: Step 1: Dissolve aminosilane in a 70wt% ethanol aqueous solution at a solid-liquid ratio of 1g:12mL, stir thoroughly to make it homogeneous, and then adjust the pH of the solution to 4.0 with acetic acid to obtain a silane solution; immerse montmorillonite in the prepared silane solution at a solid-liquid ratio of 1g:6mL, and stir continuously at a constant temperature of 75℃ for 3 hours. After stirring, separate the solid, wash it three times with anhydrous ethanol, and then dry it to obtain pretreated montmorillonite; add the pretreated montmorillonite to a 5wt% phosphate ester compound aqueous solution at a solid-liquid ratio of 1g:10mL, and then adjust the pH of the reaction system to 2.0 with 0.1mol / L hydrochloric acid. Stir continuously at 78℃ for 8 hours. After stirring, cool naturally to room temperature, centrifuge, wash repeatedly with water until the filtrate is neutral, and dry to obtain modified montmorillonite; Step 2: Polyester chips, melamine polyphosphate, and modified montmorillonite are uniformly mixed at a mass ratio of 45:3:2, and then extruded and granulated using a conventional extrusion process with a twin-screw extruder to obtain modified polyester masterbatch. The modified polyester masterbatch is then mixed with polyester chips at a mass ratio of 1:4 and spun using a conventional spinning process. The resulting fibers are then cut into filaments to obtain modified polyester fibers. These modified polyester fibers are then blended with basalt fibers at a mass ratio of 9:1 to form yarn, which is then plain-woven to obtain a fire-resistant layer with a basis weight of 250 g / m². 2 ; The heat insulation layer is an aerogel felt; The skin-friendly layer is a blend of cotton fiber and aramid 1414 in a mass ratio of 7:3, woven in a plain weave, with a weight of 180 g / m². 2 ; The aminosilane is N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane; The phosphate ester compound is dimethyl-vinyl phosphate.

[0025] Example 2 The preparation method of a heat-insulating and fire-resistant protective suit is basically the same as that in Example 1, except that the aminosilane used in the preparation method of the fire-resistant layer is γ-aminopropyltrimethoxysilane.

[0026] The heat insulation layer, skin-friendly layer, and phosphate ester compound are the same as in Example 1.

[0027] Example 3 The preparation method of a heat-insulating and fire-resistant protective suit is basically the same as that in Example 1, except that the phosphate ester compound used in the preparation method of the fire-resistant layer is dimethyl 2-hydroxyethylphosphonate.

[0028] The heat insulation layer, skin-friendly layer, and aminosilane are the same as in Example 1.

[0029] Example 4 The preparation method of a heat-insulating and fire-resistant protective suit is basically the same as that in Example 1, except that the phosphate ester compound used in the preparation method of the fire-resistant layer is dimethyl methylphosphonate.

[0030] The heat insulation layer, skin-friendly layer, and aminosilane are the same as in Example 1.

[0031] Comparative Example 1 The preparation method of a heat-insulating and fire-resistant protective suit is basically the same as that in Example 1, except that the aminosilane used in the preparation method of the fire-resistant layer is γ-aminopropyltriethoxysilane.

[0032] The heat insulation layer, skin-friendly layer, and phosphate ester compound are the same as in Example 1.

[0033] Comparative Example 2 The preparation method of a heat-insulating and fire-resistant protective suit is basically the same as that in Example 1, except that the phosphate ester compound used in the preparation method of the fire-resistant layer is dimethyl hydroxymethylphosphonate.

[0034] The heat insulation layer, skin-friendly layer, and aminosilane are the same as in Example 1.

[0035] Comparative Example 3 The preparation method of a heat-insulating and fire-resistant protective clothing is basically the same as that of Example 1, except that the modified montmorillonite is replaced with an equal amount of unmodified montmorillonite in the preparation method of the fireproof layer.

[0036] Comparative Example 4 The preparation method of a heat-insulating and fire-resistant protective clothing is basically the same as that of Example 1, except that the basalt fiber is replaced with an equal amount of modified polyester fiber in the preparation method of the fire-resistant layer.

[0037] Test Example 1 Carbon layer integrity and framework stability test This test aims to visually verify whether the "skeleton" system of the heat-insulating and fire-resistant protective clothing of this invention can form a stable and robust barrier under extreme high temperatures.

[0038] Directly observe and evaluate the fabric's ability to form a char layer, its morphological integrity, and its mechanical strength after combustion. An excellent skeleton should be able to form a continuous, dense, crack-free char layer with a certain strength, which is the physical basis for preventing flame penetration and heat transfer.

[0039] The protective suits were cut into 150mm x 150mm pieces. A propane torch was used as the standard ignition source, along with a heat flux sensor to ensure consistent heat flux density, simulating 84kW / m³. 2 The heat flux must be controlled. The sample must be fixed vertically on the fixture, with a residual carbon collection device placed below. Ignite the sample center with a flame source for 20 seconds.

[0040] After combustion, observe the continuity of the char layer, the presence of cracks, holes, and pulverization using a stereomicroscope. An excellent framework should form a complete and integrated char layer.

[0041] For the carbon layer strength test, after the sample has cooled, a flat-head probe of a micro-force gauge is used to gently press the center of the carbon layer at a constant speed, and the maximum force value when the carbon layer is crushed is recorded. This force value directly reflects the mechanical strength of the carbon layer; the higher the force value, the stronger the supporting effect of the skeleton. Each group is tested three times, and the average value is taken.

[0042] The results are shown in Table 1.

[0043] Table 1 ; Test Example 2 Thermal barrier performance test The temperature change of the back side (the side facing the skin) of a fabric over time is measured when it is subjected to standard heat radiation. The slower the temperature rise and the lower the final temperature, the better the fabric's heat-barrier properties and the more effective the protection for the internal components.

[0044] The heat-insulating and fire-resistant protective clothing of this invention was cut to the specified size. A silicon carbide rod heater was used as the heat radiation source. A precisely measured thermocouple was placed in close contact with the back of the sample for real-time temperature recording. The heat radiation source was adjusted to a setting corresponding to 84 kW / m². 2 The heat flux density was measured, and thermal radiation was applied to the front of the sample. Simultaneously, the time required for the back side temperature to rise by 24°C was recorded; the longer this time, the better the fabric's thermal protection performance (TPP value). Each group was tested three times, and the average value was taken.

[0045] The test results are shown in Table 2.

[0046] Table 2 ; This invention achieves synergistically enhanced fireproofing and heat insulation effects through meticulous chemical design and material compounding. Its core mechanism likely lies in the following: First, surface modification of montmorillonite using N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane not only improves its compatibility with polymers but, more importantly, introduces highly reactive diamino functional groups. Subsequently, a vinyl-containing phosphate ester is selected, and under acidic conditions, a highly efficient covalent bonding reaction is used to firmly graft the flame retardant onto the modified montmorillonite, effectively preventing the migration and loss of the flame retardant and ensuring the durability of the flame retardant effect. At the macroscopic material structure level, the modified montmorillonite is blended with polyester chips and melamine polyphosphate to obtain modified polyester fibers, which are then blended with basalt fibers in a specific ratio. Basalt fiber, as a natural inorganic fiber, has a high melting point and is non-flammable, serving as a heat-resistant skeleton in the composite material. In extreme combustion environments, the polymer matrix may undergo pyrolysis or softening, while basalt fibers can maintain their fiber shape. Together with montmorillonite, which is chemically modified and uniformly dispersed in the matrix, they support the expanded carbon layer formed by the modified montmorillonite and other additives, preventing it from collapsing. This creates a continuous, dense physical barrier with good mechanical strength. This barrier can effectively block flames and high temperatures, and greatly delay the penetration of heat, thereby significantly improving the overall thermal protection performance of the protective clothing.

Claims

1. A method for the production of a heat- and flame-protective suit, characterized in that, The method is as follows: The fireproof layer, the heat insulation layer and the skin-friendly layer are sequentially sewn from outside to inside by sewing thread to obtain the heat insulation and fireproof protective clothing. The preparation method of the fireproof layer is as follows: Step 1: Dissolve the aminosilane in an ethanol aqueous solution, stir and adjust the pH value of the solution to be acidic to obtain a silane solution; immerse the montmorillonite in the silane solution, stir under heating conditions, separate the solid after completion, wash and dry to obtain pretreated montmorillonite; Add the pretreated montmorillonite to a phosphonate compound aqueous solution, adjust the pH value of the reaction system to be acidic, stir under heating conditions, separate, wash and dry after completion to obtain modified montmorillonite; Step 2: Mix the polyester chips, melamine polyphosphate and the modified montmorillonite in proportion, melt extrude and granulate to obtain modified polyester master granules; mix the modified polyester master granules and polyester chips in proportion, spin by using a conventional spinning process, cut the yarn to obtain modified polyester fibers, mix the modified polyester fibers and basalt fibers in proportion to form yarn, and then weave by plain weave to obtain the fireproof layer.

2. The method of manufacturing a heat and flame protective garment according to claim 1, wherein, The preparation method of the fireproof layer is as follows: Step 1: Dissolve the aminosilane in an ethanol aqueous solution of 60-80 wt%, fully stir to make it uniform, then adjust the pH value of the solution to 4-5 by using acetic acid to obtain a silane solution; immerse the montmorillonite in the prepared silane solution in a solid-liquid ratio of 0.5-2 g:4-8 mL, continuously stir at a constant temperature of 70-80℃ for 1-5 hours, separate the solid after completion of stirring, wash with anhydrous ethanol for 1-3 times, and then dry to obtain pretreated montmorillonite; add the pretreated montmorillonite to a 3-7 wt% phosphonate compound aqueous solution in a solid-liquid ratio of 0.5-2 g:5-15 mL, then use 0.05-0.2 mol / L hydrochloric acid to adjust the pH value of the reaction system to 1.5-3, continuously stir at 75-80℃ for 5-10 hours, naturally cool to room temperature after completion of stirring, centrifugally separate, repeatedly wash with water until the filtrate is neutral, and dry to obtain modified montmorillonite; Step 2: Mix the polyester chips, melamine polyphosphate and the modified montmorillonite in proportion, melt extrude and granulate by using a conventional extrusion process through a double-screw extruder to obtain modified polyester master granules; mix the modified polyester master granules and polyester chips in proportion by using a conventional spinning process to spin, cut the yarn to obtain modified polyester fibers, mix the modified polyester fibers and basalt fibers in proportion to form yarn, and then weave by plain weave to obtain the fireproof layer.

3. The method of making a thermal fire protective garment of claim 1, wherein, The heat insulation layer is aerogel felt.

4. The method of making a thermal fire protective garment of claim 1, wherein, The skin-friendly layer is a plain weave fabric made of cotton fiber and aramid fiber 1414 blended at a mass ratio of 5-10:1-5, with a grammage of 150-200 g / m 2 .

5. The method of making a thermal fire protective garment of claim 1, wherein, The stitch density of the sewing thread is 4-5 stitches per centimeter.

6. The method of manufacturing a heat and flame protective garment according to claim 1 or 2, wherein The aminosilane in step 1 is dissolved in an ethanol aqueous solution of 60-80 wt% in a solid-liquid ratio of 0.5-2 g:8-15 mL.

7. The method of manufacturing a heat and flame protective garment according to claim 1 or 2, wherein The aminosilane is at least one of γ-aminopropyltrimethoxysilane and N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane.

8. The method of manufacturing a heat and flame protective garment according to claim 1 or 2, wherein The phosphonate compound is at least one of dimethyl methylphosphonate, dimethyl-vinylphosphonate and 2-hydroxyethyl dimethylphosphonate.

9. The method of manufacturing a heat and flame protective garment according to claim 1 or 2, wherein The fireproof layer has a gram weight of 200-300 g / m 2 .

10. A thermal and flame protective garment, characterized in that, Prepared using the method of any one of claims 1-9.