A SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric, its preparation method and application

Abstract

This invention belongs to the technical field of fireproof and heat-insulating materials, specifically relating to a SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric, its preparation method, and its application. The SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric provided by this invention includes basalt fiber fabric, SiO2 aerogel bonded to the surface and pores of the basalt fiber fabric via hydrogen bonds, and a TiO2 reflective layer bonded to the surface of the SiO2 aerogel by an organosilicon resin curing agent. This invention utilizes the combination of the excellent fire-resistant properties of basalt fiber fabric, the three-dimensional network structure of SiO2 aerogel, and nano-TiO2 particles with high heat radiation reflectivity to form a good fireproof and heat-insulating composite material, which, as the outermost fabric of fire-resistant clothing, can achieve fireproof and heat-insulating functions.

Description

Technical Field

[0001] This invention belongs to the field of fireproof and heat-insulating materials technology, specifically relating to a SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric, its preparation method, and its application. Background Technology

[0002] Faced with complex fire scene environments, firefighters primarily conduct rescue operations in three ways: around the fire scene, close to the fire source, and traversing the fire scene to reach the fire source. The temperature in the fire scene's thermal environment is generally 60–1100℃, while its radiant heat is 115–200 kW / m². 2 This necessitates the use of high-level fire-resistant clothing to avoid injury in harsh rescue environments, improve work efficiency, and enhance safety.

[0003] Firefighting suits, which commonly utilize various fabric structures, primarily employ a four-layer design: an outer layer, a waterproof and breathable layer, a heat-insulating layer, and a lining layer. Specifically: the outer layer fabric possesses excellent flame-retardant and heat-resistant properties; the waterproof and breathable layer, closely adhering to the outer fabric, not only prevents external water ingress but also allows water vapor generated by the wearer to escape; the heat-insulating layer prevents the conduction of external heat; and the lining layer primarily enhances the wearer's comfort. This multi-layered structure gives firefighting protective suits excellent flame-retardant, heat-insulating, and radiant heat penetration resistance properties, but it also increases the weight of the suit and reduces its breathability.

[0004] Existing flame-retardant fiber-based fabrics include PMIA, phenolic fibers, and PBO, but these organic fibers all have pyrolysis temperatures below 600℃, failing to meet the environmental requirements for composite fabrics. For the insulation layer, aerogel is an excellent insulation material. It possesses a nanoscale porous network structure with pore sizes ranging from 1 to 100 nm. Gas accounts for 96% of the composition of aerogel materials, with a porosity reaching up to 99.8% and a minimum density of 0.003 g / cm³. 3 It has a surface area only 2.75 times that of air, and an extremely low thermal conductivity of only 0.013 W / (m·K), half that of still air, with a light transmittance of up to 99%. The nanoporous structure of aerogel endows it with high specific surface area, low thermal conductivity, excellent insulation and heat insulation properties, effectively reducing heat transfer and exhibiting excellent thermal insulation performance. However, pure aerogel is almost entirely transparent to near-infrared radiation in the 3–8 pm range, while radiation at temperatures of 300–1300 K is mainly in this band. At high temperatures, radiative heat transfer is the primary energy transfer mechanism; therefore, pure aerogel has very poor performance in suppressing high-temperature radiation. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric, its preparation method and application. The SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric provided by the present invention has excellent high temperature resistance and heat radiation reflection capabilities, and can achieve fireproof and heat insulation functions.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric, comprising basalt fiber fabric, SiO2 aerogel bonded to the surface and pores of the basalt fiber fabric by hydrogen bonding, and a TiO2 reflective layer bonded to the surface of the SiO2 aerogel by an organosilicon resin curing agent.

[0008] Preferably, the SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric has a thickness of 2-8 mm and a density of 2500-3500 kg / m³. 3 The allowable operating temperature is 200~350℃, the specific heat capacity is 0.1~0.2KJ / (kg·℃), and the thermal conductivity is 0.04~0.1W / (m·℃).

[0009] This invention also provides a method for preparing the SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric described in the above technical solution, comprising the following steps:

[0010] The mixture obtained by mixing the first silica sol and the polyvinyl alcohol aqueous solution was electrospun to obtain a polyvinyl alcohol-SiO2 fiber membrane.

[0011] The polyvinyl alcohol-SiO2 fiber membrane was calcined, and the resulting SiO2 fiber membrane was broken up and mixed with water to disperse it, thus obtaining a SiO2 fiber dispersion.

[0012] The basalt fiber fabric is first impregnated in the mixture of the SiO2 fiber dispersion and the second silica sol, and the resulting first impregnation mixture is freeze-dried to obtain the SiO2 aerogel / basalt composite fabric.

[0013] The SiO2 aerogel / basalt composite fabric is subjected to a second impregnation in a mixture of nano-TiO2 powder and organosilicon resin curing agent. The resulting second impregnation mixture is then cured to obtain the SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric.

[0014] Preferably, the mass ratio of the first silica sol to the polyvinyl alcohol aqueous solution is 1:1 to 3; the mass of polyvinyl alcohol in the polyvinyl alcohol aqueous solution is 5 to 15% of the mass of water.

[0015] Preferably, the conditions for electrospinning include: a spinning voltage of 16-20 kV, a needle size of 18-24 G, a spinning solution speed of 1.0-1.5 mL / h, a receiving distance of 15-21 cm, an ambient temperature of 19-25 °C, and an ambient humidity of 20-25%.

[0016] Preferably, the calcination temperature is 800–1000°C; and the calcination holding time is 1–3 hours.

[0017] Preferably, the concentration of the SiO2 fiber membrane in the SiO2 fiber dispersion is 5–15 mg / mL.

[0018] Preferably, the mass of the nano-TiO2 powder is 1-15% of the mass of the organosilicon resin curing agent.

[0019] Preferably, the curing includes a first-stage curing, heating, and a second-stage curing; the temperature of the first-stage curing is 60–80°C; the holding time of the first-stage curing is 1–2 hours; the temperature of the second-stage curing is 90–120°C; and the holding time of the second-stage curing is 1–3 hours.

[0020] The present invention also provides the application of the SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric described in the above technical solution or the SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric prepared by the preparation method described in the above technical solution in fire-resistant clothing.

[0021] This invention provides a SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric, comprising basalt fiber fabric, SiO2 aerogel bonded to the surface and pores of the basalt fiber fabric by hydrogen bonding, and a TiO2 reflective layer bonded to the surface of the SiO2 aerogel by an organosilicon resin curing agent.

[0022] The SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric provided by this invention features basalt fiber fabric that is non-combustible and heat-resistant (1100℃), exhibiting excellent fire resistance. SiO2 aerogel, due to its internal nanoscale porous framework, possesses good heat insulation properties, but its ability to suppress high-temperature radiation is poor. To address the issue of poor heat radiation reflection at high temperatures, this invention incorporates TiO2 as a reflective filler. Nano-TiO2 particles have a strong scattering and absorption effect on radiation, significantly increasing the overall extinction coefficient of the material, suppressing high-temperature radiation, improving heat radiation reflection capability, and solving the heat insulation problem at high temperatures. This invention utilizes the combination of fire-resistant basalt fiber fabric, the three-dimensional network structure of SiO2 aerogel, and nano-TiO2 particles to form a good fireproof and heat-insulating composite material, which, as the outermost fabric of fire-resistant clothing, achieves both fireproof and heat insulation functions. Attached Figure Description

[0023] Figure 1 Scanning electron microscope (SEM) images of the polyvinyl alcohol-SiO2 fiber membrane prepared in Example 1 of this invention before and after calcination;

[0024] Figure 2 Thermogravimetric curves of the polyvinyl alcohol-SiO2 fiber membrane prepared in Example 1 of this invention before and after calcination;

[0025] Figure 3 Scanning electron microscope image and physical image of the SiO2 aerogel / basalt composite fabric prepared in Example 1 of this invention;

[0026] Figure 4 Temperature change curves of SiO2 aerogel / basalt composite fabrics prepared from SiO2 fiber dispersions with different SiO2 fiber membrane concentrations at 100℃.

[0027] Figure 5 Thermal conductivity and its fitting curves for SiO2 aerogel / basalt composite fabrics prepared from SiO2 fiber dispersions with different SiO2 fiber membrane concentrations.

[0028] Figure 6 The thermal insulation test results of the SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric and basalt fiber fabric prepared in Example 1 of the present invention at 100°C are shown.

[0029] Figure 7 The graph shows the thermal stability test results of the SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric prepared in Example 1 of the present invention.

[0030] Figure 8 The microstructure diagrams are of the SiO2 aerogel / basalt composite fabric prepared in Example 1 and the SiO2 aerogel prepared in Comparative Example 3.

[0031] Figure 9 This is a physical image of the SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric prepared in Example 1 of the present invention. Detailed Implementation

[0032] This invention provides a SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric, comprising basalt fiber fabric, SiO2 aerogel bonded to the surface and pores of the basalt fiber fabric by hydrogen bonding, and a TiO2 reflective layer bonded to the surface of the SiO2 aerogel by an organosilicon resin curing agent.

[0033] In this invention, the thickness of the SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric is preferably 2-8 mm, more preferably 3-6 mm, and the density is preferably 2500-3500 kg / m³. 3 More preferably, it is 2600–3000 kg / m³. 3 The allowable operating temperature is preferably 200–350℃, more preferably 240–300℃; the specific heat capacity is preferably 0.1–0.2 KJ / (kg·℃), more preferably 0.1–0.15 KJ / (kg·℃); the thermal conductivity is preferably 0.04–0.1 W / (m·℃), more preferably 0.05–0.07 W / (m·℃); the thickness of the SiO2 aerogel is preferably 1–4 mm, more preferably 2–3 mm; the thickness of the TiO2 reflective layer is preferably 1–4 mm, more preferably 2–3 mm.

[0034] In this invention, the mass of SiO2 in the SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric prepared from basalt fiber fabric of 10cm×10cm is preferably 0.05-0.5g, more preferably 0.1-0.2g, and the mass of TiO2 is preferably 0.075-0.375g, more preferably 0.1-0.2g.

[0035] The SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric provided by this invention features basalt fiber fabric that is non-combustible and heat-resistant (1100℃), exhibiting excellent fire resistance. SiO2 aerogel, due to its internal nanoscale porous framework, possesses good heat insulation properties, but its ability to suppress high-temperature radiation is poor. To address the issue of poor heat radiation reflection at high temperatures, this invention incorporates TiO2 as a reflective filler. Nano-TiO2 particles have a strong scattering and absorption effect on radiation, significantly increasing the overall extinction coefficient of the material, suppressing high-temperature radiation, improving heat radiation reflection capability, and solving the heat insulation problem at high temperatures. This invention utilizes the combination of fire-resistant basalt fiber fabric, the three-dimensional network structure of SiO2 aerogel, and nano-TiO2 particles to form a good fireproof and heat-insulating composite material, which, as the outermost fabric of fire-resistant clothing, achieves both fireproof and heat insulation functions.

[0036] This invention provides a method for preparing the SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric described in the above technical solution, comprising the following steps:

[0037] The mixture obtained by mixing the first silica sol and the polyvinyl alcohol aqueous solution was electrospun to obtain a polyvinyl alcohol-SiO2 fiber membrane.

[0038] The polyvinyl alcohol-SiO2 fiber membrane was calcined, and the resulting SiO2 fiber membrane was broken up and mixed with water to disperse it, thus obtaining a SiO2 fiber dispersion.

[0039] The basalt fiber fabric is first impregnated in the mixture of the SiO2 fiber dispersion and the second silica sol, and the resulting first impregnation mixture is freeze-dried to obtain the SiO2 aerogel / basalt composite fabric.

[0040] The SiO2 aerogel / basalt composite fabric is subjected to a second impregnation in a mixture of nano-TiO2 powder and organosilicon resin curing agent. The resulting second impregnation mixture is then cured to obtain the SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric.

[0041] Unless otherwise specified, the present invention does not have special requirements on the source of the raw materials used in the preparation, and commercially available products well known to those skilled in the art can be used.

[0042] The present invention involves electrospinning a mixture obtained by mixing a first silica sol and a polyvinyl alcohol aqueous solution to obtain a polyvinyl alcohol-SiO2 fiber membrane.

[0043] In this invention, the preferred method for preparing the first silica sol is to mix organosilicon, distilled water, and acid and perform a first hydrolysis to obtain the first silica sol. In this invention, the organosilicon is preferably tetraethyl orthosilicate (TEOS) or methyl orthosilicate silane (TMOS), more preferably tetraethyl orthosilicate (TEOS); the mass ratio of the organosilicon to distilled water is preferably 1:1 to 5, more preferably 1:2 to 4; the acid is preferably phosphoric acid, hydrochloric acid, or oxalic acid, more preferably phosphoric acid or oxalic acid; the concentration of the hydrochloric acid is preferably 0.05 to 0.2 mol / L, more preferably 0.1 to 0.15 mol / L; the mass ratio of the acid to the organosilicon is preferably 0.01 to 0.05:1, more preferably 0.02 to 0.04:1; the first hydrolysis is preferably carried out under stirring conditions; the stirring is preferably magnetic stirring; the stirring speed is preferably 500 to 800 rpm, more preferably 600 to 700 rpm; the first hydrolysis time is preferably 12 to 24 h, more preferably 16 to 20 h.

[0044] In this invention, organosilicon is used as a precursor raw material. After hydrolysis, it condenses and polymerizes into a gel with a three-dimensional network structure to prepare silica sol. In this process, acid plays a catalytic role.

[0045] In this invention, the preferred method for preparing the polyvinyl alcohol aqueous solution is as follows: a mixture obtained by soaking polyvinyl alcohol in water is heated to 75–95°C while first stirring, then kept at this temperature, followed by a second stirring at room temperature to obtain the polyvinyl alcohol aqueous solution. In this invention, the soaking temperature is preferably 15–30°C, more preferably 20–25°C; the soaking time is preferably 3–12 hours, more preferably 5–8 hours; the mass of polyvinyl alcohol in the polyvinyl alcohol aqueous solution is preferably 5–15% of the mass of water, more preferably 5–10%; the water is preferably distilled water; the first stirring speed is preferably 400–800 rpm, more preferably 400–600 rpm; the heating is preferably to 80–90°C; the total heating and holding time is preferably 3–5 hours, more preferably 4 hours; the second stirring speed is preferably 500–800 rpm, more preferably 500–600 rpm; the second stirring time is preferably 1–4 hours, more preferably 2–3 hours.

[0046] In this invention, the mass ratio of the first silica sol to the polyvinyl alcohol aqueous solution is preferably 1:1 to 3, more preferably 1:1 to 2; the mixing is preferably carried out by stirring at room temperature; the stirring rate is preferably 500 to 800 rpm, more preferably 500 to 600 rpm; the stirring time is preferably 2 to 5 hours, more preferably 3 to 4 hours.

[0047] In this invention, the conditions for electrospinning include: a spinning voltage preferably of 16–20 kV, more preferably 17–19 kV; a needle specification preferably of 18–24 G, more preferably 20–24 G; a spinning solution speed preferably of 1.0–1.5 mL / h, more preferably 1.2–1.4 mL / h; a receiving distance preferably of 15–21 cm, more preferably 18–20 cm; an ambient temperature preferably of 19–25 °C, more preferably 20–25 °C; and an ambient humidity preferably of 20–25%, more preferably 22–24%.

[0048] After the electrospinning is completed, the present invention preferably further includes: drying the electrospinned fiber membrane obtained by electrospinning; the drying temperature is preferably 65-85℃, more preferably 70-80℃; the drying time is preferably 1-5h, more preferably 2-4h; the drying is preferably oven drying.

[0049] After obtaining the polyvinyl alcohol-SiO2 fiber membrane, the present invention calcines the polyvinyl alcohol-SiO2 fiber membrane to obtain a SiO2 fiber membrane.

[0050] In this invention, the calcination temperature is preferably 800–1000°C, more preferably 800–900°C; the calcination holding time is preferably 1–3 h, more preferably 1–2 h; and the heating rate to the calcination temperature is preferably 3–5°C / min, more preferably 5°C / min. This invention removes the organic component polyvinyl alcohol from the SiO2 fiber membrane through calcination to obtain the SiO2 fiber membrane.

[0051] After obtaining the SiO2 fiber membrane, the present invention breaks the SiO2 fiber membrane and mixes it with water to disperse it, thereby obtaining a SiO2 fiber dispersion.

[0052] In this invention, the concentration of SiO2 fiber membrane in the SiO2 fiber dispersion is preferably 5-15 mg / mL, more preferably 5-10 mg / mL; the dispersion is preferably performed using a cell disruptor; the dispersion time is preferably 1-6 min, more preferably 2-5 min; and the disruption is preferably performed by shearing.

[0053] After obtaining the SiO2 fiber dispersion, the present invention first impregnates the basalt fiber fabric in the mixture of the SiO2 fiber dispersion and the second silica sol, and freeze-dries the resulting first impregnation mixture to obtain the SiO2 aerogel / basalt composite fabric.

[0054] In this invention, the preferred method for preparing the second silica sol is to mix and disperse organosilicon, water and ethanol, and then mix the resulting dispersion with acid for a second hydrolysis to obtain the second silica sol.

[0055] In this invention, the organosilicon is preferably tetraethyl orthosilicate (TEOS) or methyl orthosilicate silane (TMOS), more preferably tetraethyl orthosilicate (TEOS); the mass ratio of the organosilicon to water is preferably 1:1 to 3, more preferably 1:1.5 to 2.5; the mass ratio of the organosilicon to ethanol is preferably 1:5 to 11, more preferably 1:6 to 10; the dispersion is preferably carried out at room temperature; the dispersion is preferably carried out under stirring conditions; the stirring speed is preferably 500 to 800 rpm, more preferably 600 to 700 rpm; the dispersion time is preferably 20 to 40 min, more preferably 25 to 35 min.

[0056] In this invention, the acid is preferably phosphoric acid, hydrochloric acid, or oxalic acid, more preferably phosphoric acid or oxalic acid; the concentration of the hydrochloric acid is preferably 0.05–0.2 mol / L, more preferably 0.1–0.15 mol / L; the mass ratio of the acid to organosilicon is preferably 0.01–0.05:1, more preferably 0.02–0.04:1; the mixing of the dispersion and the acid is preferably done by adding the acid dropwise to the dispersion; the dropwise addition is preferably done dropwise; the second hydrolysis is preferably carried out under stirring conditions; the stirring speed is preferably 500–800 rpm, more preferably 600–700 rpm; the second hydrolysis time is preferably 15–180 min, more preferably 30–60 min; the second hydrolysis is preferably carried out at room temperature.

[0057] In this invention, the preferred method for preparing the mixture of SiO2 fiber dispersion and second silica sol is to mix and stir the SiO2 fiber dispersion and the second silica sol until uniform; the stirring speed is preferably 500-800 rpm, more preferably 600-700 rpm.

[0058] In this invention, the basalt fiber fabric is preferably a plain basalt fiber fabric; during the first impregnation process, each 10cm×10cm basalt fiber fabric is preferably impregnated in a mixture of 15-30mL of SiO2 fiber dispersion and the second silica sol, more preferably in a mixture of 18-25mL of SiO2 fiber dispersion and the second silica sol.

[0059] The basalt inorganic fiber used in this invention has excellent properties. The density of basalt fiber is higher than that of glass fiber and carbon fiber; although its elastic modulus is not as high as that of carbon fiber and Kevlar 49, it is similar to that of glass fiber; its breaking strength is higher than that of carbon fiber and Kevlar 49, and comparable to that of E glass fiber; its heat resistance and flame retardant properties are significantly better than those of glass fiber, aramid, and carbon fiber, and it can maintain stable performance at 650℃ for long-term use. This invention uses basalt fiber to replace high-performance fibers (such as carbon fiber and glass fiber), which has a high cost-performance ratio.

[0060] Before freeze-drying, the present invention preferably freezes the first impregnation mixture; the freezing temperature is preferably -10 to -30°C, more preferably -20 to -25°C; the freezing time is preferably 12 to 24 hours, more preferably 16 to 20 hours.

[0061] In this invention, the freeze-drying equipment is preferably a freeze dryer; the freeze-drying temperature is preferably -20 to -40°C, more preferably -25 to -35°C; and the freeze-drying time is preferably 20 to 30 hours, more preferably 22 to 28 hours.

[0062] In this invention, the SiO2 aerogel / basalt composite fabric includes a basalt composite fabric and SiO2 aerogel covering the surface and pores of the basalt composite fabric; the SiO2 aerogel includes a second silica sol and a SiO2 fiber membrane dispersed in the second silica sol.

[0063] After obtaining the SiO2 aerogel / basalt composite fabric, the present invention performs a second impregnation of the SiO2 aerogel / basalt composite fabric in a mixture of nano-TiO2 powder and organosilicon resin curing agent, and the resulting second impregnation mixture is cured to obtain SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric.

[0064] In this invention, the silicone resin curing agent is preferably silicone resin A and curing agent B; silicone resin A and curing agent B are purchased from Hangzhou Weisichuang Technology Co., Ltd.; silicone resin A is model C-0030A; silicone resin B is model C-0030B; the silicone resin curing agent is preferably obtained by mixing and stirring silicone resin A and curing agent B evenly; the stirring speed is preferably 500-800 rpm, more preferably 600-700 rpm; the mass ratio of silicone resin A to curing agent B is preferably 1:1.

[0065] In this invention, the particle size of the nano-TiO2 powder is preferably 15-50 nm, more preferably 20-30 nm; the mass of the nano-TiO2 powder is preferably 1-15% of the mass of the organosilicon resin curing agent, more preferably 5-10%; the mixture of nano-TiO2 powder and organosilicon resin curing agent is preferably obtained by mixing and stirring the nano-TiO2 powder and organosilicon resin curing agent evenly; the stirring speed is preferably 500-800 rpm, more preferably 600-700 rpm.

[0066] This invention uses nano-TiO2 powder as a reflective filler. Its particles have strong scattering and absorption properties for radiation, significantly increasing the overall extinction coefficient of the aerogel material and suppressing high-temperature radiation. TiO2 is a broadband absorber; when light with a band gap greater than that of TiO2 irradiates the particles, the light energy is stored in the particles as chemical energy. Part of the light energy is absorbed, and simultaneously, due to the scattering effect of TiO2, some light energy is scattered away, achieving a light shielding effect.

[0067] In the second impregnation process, the SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric prepared from basalt fiber fabric of 10cm×10cm is preferably impregnated in a mixture of 15-35mL of nano TiO2 powder and organosilicon resin curing agent, more preferably in a mixture of 20-28mL of nano TiO2 powder and organosilicon resin curing agent.

[0068] In this invention, the curing preferably includes a first-stage curing, heating, and a second-stage curing; the temperature of the first-stage curing is preferably 60-80°C, more preferably 65-75°C; the holding time of the first-stage curing is preferably 1-2 hours, more preferably 2 hours; the temperature of the second-stage curing is preferably 90-120°C, more preferably 100-110°C; the holding time of the second-stage curing is preferably 1-3 hours, more preferably 2 hours; and the heating rate is preferably 4-15°C / min, more preferably 6-10°C / min.

[0069] The present invention also provides the application of the SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric described in the above technical solution or the SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric prepared by the preparation method described in the above technical solution in fire-resistant clothing.

[0070] The present invention does not impose any special limitations on the application of the SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric in fireproof clothing; any application method known in the art can be used.

[0071] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0072] Materials used in the following embodiments:

[0073] Ethyl orthosilicate (analytical grade, Chengdu Kelong Chemical Co., Ltd.)

[0074] Phosphoric acid (analytical grade, Shanghai Aladdin Biochemical Technology Co., Ltd.)

[0075] Polyvinyl alcohol (Shandong Yousuo Chemical Technology Co., Ltd.)

[0076] Ethanol (analytical grade, Tianjin Tianli Chemical Reagent Co., Ltd.)

[0077] Distilled water (homemade),

[0078] Basalt fiber plain weave fabric (manufactured by Shanxi Jinzhong Basalt Development Co., Ltd.)

[0079] Organosilicon resin-A, organosilicon resin-B (C-0030A, C-0030B, Hangzhou Weisichuang Technology Co., Ltd.)

[0080] Nano titanium dioxide (analytical grade, Shanghai Aladdin Biochemical Technology Co., Ltd.)

[0081] Example 1

[0082] (1) Preparation of polyvinyl alcohol-SiO2 fiber membrane by electrospinning:

[0083] Preparation of silica sol: Weigh tetraethyl orthosilicate (TEOS), distilled water (H2O) and phosphoric acid (H3PO4) in a mass ratio of 1:1:0.02, mix them, and then perform hydrolysis by magnetic stirring at 500 rpm for 12 hours at room temperature;

[0084] Preparation of aqueous solution of polyvinyl alcohol (PVA): Add 10% by mass of PVA to distilled water and soak for 5 hours. Then heat the resulting mixture to 80°C while stirring at 400 rpm and keep it at that temperature for a total of 3 hours. After that, adjust the speed to 500 rpm and continue stirring at room temperature for 1 hour.

[0085] Electrospinning: The silica sol and PVA aqueous solution were mixed at a mass ratio of 1:1 and stirred at 500 rpm for 3 hours at room temperature until they were uniformly mixed. Then, electrospinning was performed with a spinning voltage of 17 kV, a needle size of 18 G, a spinning solution speed of 1.5 mL / h, a receiving distance of 20 cm, an ambient temperature of 23 ℃, and a humidity of 20%. The resulting electrospinned fiber membrane with uniform thickness was dried in an oven at 80 ℃ for 2 hours to obtain a polyvinyl alcohol-SiO2 fiber membrane.

[0086] (2) Preparation of SiO2 aerogel / basalt composite fabric;

[0087] The dried polyvinyl alcohol-SiO2 fiber membrane was peeled off the tin foil, laid flat in a crucible, and calcined in a muffle furnace at a rate of 5℃ / min to 800℃ for 1h to remove the organic component PVA, thus obtaining the SiO2 fiber membrane.

[0088] The obtained SiO2 fiber membrane was cut into small pieces and dissolved in distilled water. It was then broken up with a cell disruptor for 2 minutes to disperse it evenly, resulting in a SiO2 fiber dispersion with a concentration of 7.5 mg / mL.

[0089] Preparation of silica sol: Tetraethyl orthosilicate, water and ethanol were mixed in a mass ratio of 1:1:10 (the amount of silicon source was the same as the amount of silicon film) and stirred at 500 rpm for 30 min at room temperature to disperse it evenly. Then phosphoric acid was added dropwise (the mass ratio of phosphoric acid to tetraethyl orthosilicate was 0.02:1) and stirring was continued for hydrolysis for 15 min.

[0090] The fiber dispersion and silica sol were mixed and stirred evenly at 500 rpm and then poured into a mold. The cut basalt fiber plain weave fabric was placed in the mold and allowed to be fully impregnated. The mold was frozen at -10℃ for 12 hours to form a block and then placed in a freeze dryer at -25℃ for 24 hours to produce SiO2 aerogel / basalt composite fabric.

[0091] (3) Addition of TiO2 reflective layer

[0092] Organosilicon resin A and curing agent B (C-0030A and C-0030B from Hangzhou Weisichuang Technology Co., Ltd.) were mixed at a mass ratio of 1:1 and stirred evenly at 500 rpm. Nano TiO2 powder (accounting for 10% of the total mass of organosilicon resin A and curing agent B, with a particle size of 25 nm) was added and stirred evenly again. The mixture was poured into a mold, and the resulting SiO2 aerogel / basalt composite fabric was placed in it. After it was completely impregnated, it was cured at 60℃ for 1 hour in the first stage, and then the temperature was increased to 100℃ at a rate of 10℃ / min for the second stage of curing for 1 hour to obtain the SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric.

[0093] Example 2

[0094] The difference from Example 1 is that the concentration of SiO2 fiber membrane in the SiO2 fiber dispersion is 5 mg / mL, while the rest is the same as in Example 1.

[0095] Example 3

[0096] The difference from Example 1 is that the concentration of SiO2 fiber membrane in the SiO2 fiber dispersion is 10 mg / mL, while the rest is the same as in Example 1.

[0097] Example 4

[0098] The difference from Example 1 is that the concentration of SiO2 fiber membrane in the SiO2 fiber dispersion is 15 mg / mL, while the rest is the same as in Example 1.

[0099] Comparative Example 1

[0100] The difference from Example 1 is that the concentration of SiO2 fiber membrane in the SiO2 fiber dispersion is 0 mg / mL, while the rest is the same as in Example 1.

[0101] Comparative Example 2

[0102] The difference from Example 1 is that the concentration of SiO2 fiber membrane in the SiO2 fiber dispersion is 2.5 mg / mL, while the rest is the same as in Example 1.

[0103] Comparative Example 3

[0104] The difference from Example 1 is that the SiO2 aerogel is prepared using a traditional method—the sol-gel method. The specific preparation method is as follows:

[0105] (1) Mix TEOS, anhydrous ethanol and deionized water in a molar ratio of 1:1:10 and stir magnetically for 10 min at room temperature.

[0106] (2) Add a certain amount of dilute hydrochloric acid (0.1 mol / L) dropwise and continue stirring for 30 minutes to mix it evenly;

[0107] (3) Seal the mixed solution and place it in a constant temperature water bath for hydrolysis at a certain temperature for a period of time.

[0108] (4) Place the mixed solution in a magnetic stirrer and add a certain amount of N,N-dimethylformamide (DMF) and dilute ammonia (NH3H2O) dropwise while stirring to obtain SiO2 alcohol gel;

[0109] (5) The obtained alcohol gel was aged at room temperature for 24 hours, and aged for 24 hours each at a certain temperature using 20% ​​(volume fraction) H2O / EtOH and 20% (volume fraction) TEOS / EtOH solutions as aging solutions.

[0110] (6) Five solvent replacement steps were performed in isopropanol (IPA), 75% (volume fraction) IPA / n-hexane (Hexane), 50% (volume fraction) IPA / Hexane, 25% (volume fraction) IPA / Hexane, and Hexane, with a replacement temperature of 50°C;

[0111] (7) Surface modification was performed using a 10% (volume ratio) trimethylchlorosilane (TMCS) / Hexane solution at 40°C; the surface was cleaned with n-hexane 4 times, 6 hours each time, at a cleaning temperature of 50°C.

[0112] (8) Dry at room temperature for 24 hours, at 60°C for 12 hours, and at 100°C, 150°C and 200°C for 1 hour each to obtain SiO2 aerogel.

[0113] Performance testing

[0114] (1) The polyvinyl alcohol-SiO2 fiber membrane prepared in Example 1 of this invention was observed by scanning electron microscopy before and after calcination. The results are as follows: Figure 1 As shown, a represents the state before calcination, and b represents the state after calcination.

[0115] from Figure 1 It can be seen that the fiber diameter changes significantly after calcination, which is due to the removal of the organic component PVA.

[0116] (2) Thermogravimetric analysis was performed on the polyvinyl alcohol-SiO2 fiber membrane prepared in Example 1 of the present invention before and after calcination, and the results are as follows: Figure 2 As shown.

[0117] like Figure 2 As shown, calcination can successfully remove the organic component polyvinyl alcohol (PVA) to obtain SiO2 fiber membrane, and also indicates that SiO2 fibers can withstand high temperature of 1000℃.

[0118] (3) The SiO2 aerogel / basalt composite fabric prepared in Example 1 of this invention was observed by electron microscopy, and the results are as follows: Figure 3 As shown, a represents the three-dimensional porous structure of the aerogel, b represents the bonding effect of silica sol at the nanofiber connection points, and c represents a macroscopic photograph of the prepared aerogel.

[0119] like Figure 3 As can be seen from a, the ice crystals formed during the freezing of the SiO2 fiber dispersion sublimated after freeze-drying, leaving pores that formed a three-dimensional network structure. Figure 3 As can be seen in b, the connection points between fibers form effective links under the action of silica sol.

[0120] (4) The thermal insulation and thermal conductivity of SiO2 aerogel / basalt composite fabrics prepared with SiO2 fiber dispersions of different SiO2 fiber membrane concentrations were tested, and the results are as follows: Figure 4 and Figure 5 As shown.

[0121] from Figure 4 and Figure 5 It can be seen that the addition of SiO2 improves the thermal insulation of the composite fabric, and the effect increases with the increase of SiO2 content. However, when the SiO2 fiber membrane concentration reaches 7.5 mg / mL, the increase in effect is no longer significant.

[0122] (5) The thermal insulation properties of the SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric and basalt fiber fabric prepared in Example 1 were tested at 100°C. The results are as follows: Figure 6 As shown.

[0123] like Figure 6 As shown, a second-degree burn requires a temperature above 70°C for 1 minute. The heat insulation properties of the SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric prepared after adding TiO2 reflective filler can be kept below 70°C within 1 minute.

[0124] (6) The SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric prepared in Example 1 was subjected to thermal stability testing, and the results are as follows: Figure 7 As shown.

[0125] like Figure 7 As shown, the fabric color is slightly yellowed and there is slight curling around the edges. The fabric quality change rate is 1.10% and the size change rate is ≤10%, which is within the standard allowable range. This indicates that the fabric material itself has not decomposed and the basic properties of the fabric do not change at high temperatures, so it can be used normally.

[0126] (7) The microstructures of the SiO2 aerogel / basalt composite fabric prepared in Example 1 and the SiO2 aerogel prepared in Comparative Example 3 were tested, and the results are as follows: Figure 8 As shown, a is a macroscopic view of aerogel prepared by the traditional sol-gel method in Comparative Example 3, c is its microstructure diagram, b is a macroscopic view of aerogel prepared by ice crystal induction molding in Example 1, and d is its microstructure diagram.

[0127] Depend on Figure 8 It is evident that a significant drawback of the SiO2 aerogel sample prepared using the traditional sol-gel method in Comparative Example 3 is its brittleness, which prevents the full utilization of the aerogel's overall three-dimensional network structure. In contrast, the aerogel prepared by the ice crystal-induced molding method in this invention transforms the traditional beaded structure into a nanofiber structure, greatly enhancing its flexibility.

[0128] (8) The actual product of the SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric prepared in Example 1 of this invention is shown below. Figure 9 As shown.

[0129] from Figure 9 It can be seen that the SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric prepared by the present invention has a certain degree of flexibility and moderate thickness after having a certain heat insulation effect, and can be applied to fireproof and heat-insulating fabrics.

[0130] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric, characterized in that, It includes basalt fiber fabric, SiO2 aerogel bonded to the surface and pores of the basalt fiber fabric by hydrogen bonding, and TiO2 reflective layer bonded to the surface of the SiO2 aerogel by organosilicon resin and curing agent; The SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric has a thickness of 2~8mm and a density of 2500~3500kg / m³. 3 The allowable operating temperature is 200~350℃, the specific heat capacity is 0.1~0.2KJ / (kg·℃), and the thermal conductivity is 0.04~0.1W / (m·℃). The preparation method of the SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric includes the following steps: The mixture obtained by mixing the first silica sol and the polyvinyl alcohol aqueous solution was electrospun to obtain a polyvinyl alcohol-SiO2 fiber membrane. The polyvinyl alcohol-SiO2 fiber membrane was calcined, and the resulting SiO2 fiber membrane was broken up and mixed with water to disperse it, thus obtaining a SiO2 fiber dispersion. The basalt fiber fabric is first impregnated in a mixture of the SiO2 fiber dispersion and the second silica sol, and the resulting first impregnation mixture containing the basalt fiber fabric is freeze-dried to obtain a SiO2 aerogel / basalt composite fabric. The SiO2 aerogel / basalt composite fabric is subjected to a second impregnation in a mixture composed of nano-TiO2 powder, organosilicon resin and curing agent. The resulting second impregnation mixture containing the SiO2 aerogel / basalt composite fabric is cured to obtain the SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric.

2. The preparation method of the SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric according to claim 1, characterized in that, Includes the following steps: The mixture obtained by mixing the first silica sol and the polyvinyl alcohol aqueous solution was electrospun to obtain a polyvinyl alcohol-SiO2 fiber membrane. The polyvinyl alcohol-SiO2 fiber membrane was calcined, and the resulting SiO2 fiber membrane was broken up and mixed with water to disperse it, thus obtaining a SiO2 fiber dispersion. The basalt fiber fabric is first impregnated in a mixture of the SiO2 fiber dispersion and the second silica sol, and the resulting first impregnation mixture containing the basalt fiber fabric is freeze-dried to obtain a SiO2 aerogel / basalt composite fabric. The SiO2 aerogel / basalt composite fabric is subjected to a second impregnation in a mixture composed of nano-TiO2 powder, organosilicon resin and curing agent. The resulting second impregnation mixture containing the SiO2 aerogel / basalt composite fabric is cured to obtain the SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric.

3. The preparation method according to claim 2, characterized in that, The mass ratio of the first silica sol to the polyvinyl alcohol aqueous solution is 1:1 to 3; the mass of polyvinyl alcohol in the polyvinyl alcohol aqueous solution is 5 to 15% of the mass of water.

4. The preparation method according to claim 2 or 3, characterized in that, The conditions for electrospinning include: spinning voltage of 16~20kV, needle size of 18~24G, spinning solution speed of 1.0~1.5mL / h, receiving distance of 15~21cm, ambient temperature of 19~25℃, and ambient humidity of 20~25%.

5. The preparation method according to claim 2, characterized in that, The calcination temperature is 800~1000℃; the calcination holding time is 1~3h.

6. The preparation method according to claim 2, characterized in that, The concentration of SiO2 fibers in the SiO2 fiber dispersion is 5~15 mg / mL.

7. The preparation method according to claim 2, characterized in that, The mass of the nano-TiO2 powder is 1-15% of the total mass of the silicone resin and curing agent.

8. The preparation method according to claim 2, characterized in that, The curing process includes a first-stage curing, heating, and a second-stage curing; the temperature for the first-stage curing is 60~80℃; the holding time for the first-stage curing is 1~2h; the temperature for the second-stage curing is 90~120℃; and the holding time for the second-stage curing is 1~3h.

9. The application of the SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric of claim 1 or the SiO2 aerogel / TiO2-basalt fireproof and heat-insulating composite fabric prepared by any one of claims 2 to 8 in fire-resistant clothing.

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