Lightweight heat preservation and insulation base material, preparation method thereof and lightweight heat preservation and insulation material

Abstract

The invention relates to a light heat preservation and insulation base material, a preparation method thereof and a light heat preservation and insulation material, and belongs to the technical field of heat preservation and insulation materials. The preparation method of the light thermal insulation base material comprises the following steps: mixing inorganic fibers, an inorganic porous material and water to obtain a mixed fiber suspension; mixing the mixed fiber suspension with a foaming agent, and carrying out mixed foaming to obtain foam slurry; the foam slurry is subjected to slurry distribution and forming, a wet paper sheet is obtained, and the light heat preservation and heat insulation base material is obtained through foam elimination and drying. The lightweight thermal insulation base material prepared by the preparation method of the thermal insulation base material provided by the invention has better uniformity, lower density, higher porosity and higher aerogel loading capacity, and the thermal insulation material containing the lightweight thermal insulation base material has the advantages of light weight, excellent thermal insulation performance and temperature resistance.

Description

Technical Field

[0001] The invention relates to the technical field of thermal insulation materials, and in particular to a lightweight thermal insulation substrate and a preparation method thereof, and a lightweight thermal insulation material. Background Art

[0002] Inorganic non-metallic fiber materials such as glass fiber, ceramic fiber, high silica fiber, quartz fiber, etc. have excellent properties of good heat resistance, high strength, oxidation resistance, thermal insulation, and good electrical insulation. They have been widely used as thermal insulation materials and functional materials in the field of industrial fibers, and play an important role in the fields of petrochemicals, energy batteries, national defense science and technology, etc. With the advancement of technology in the industry, new requirements have been put forward for the loading amount, thermal conductivity and uniformity of thermal insulation substrate aerogel.

[0003] In the traditional wet molding system, since inorganic non-metallic fibers are difficult to disperse, easy to flocculate and dehydrate quickly in the water system, the prepared thermal insulation substrate has poor uniformity, low porosity and high density. Therefore, the thermal insulation substrate prepared by the water-based wet molding has a low aerogel loading and high thermal conductivity.

[0004] Therefore, there is an urgent need to provide a new method for preparing a thermal insulation substrate. Summary of the invention

[0005] In view of one or more technical problems existing in the prior art, the present invention provides a lightweight thermal insulation substrate and a preparation method thereof and a lightweight thermal insulation material. The lightweight thermal insulation substrate prepared by the preparation method of the thermal insulation substrate provided by the present invention has better uniformity, lower density, higher porosity and higher aerogel loading. The thermal insulation material containing the lightweight thermal insulation substrate has light weight, excellent thermal insulation performance and temperature resistance.

[0006] In a first aspect, the present invention provides a method for preparing a lightweight thermal insulation substrate, the preparation method comprising the following steps:

[0007] S1. Mixing inorganic fibers, inorganic porous materials and water to obtain a mixed fiber suspension;

[0008] S2. The mixed fiber suspension and the foaming agent are mixed and foamed to obtain a foam slurry;

[0009] S3. The foam slurry is spread and formed to obtain wet paper sheets, and then the foam is eliminated and dried to obtain a lightweight thermal insulation substrate.

[0010] Preferably, the inorganic fiber is one or more of glass fiber, ceramic fiber, high silica fiber, quartz fiber, and preferably, the diameter of the inorganic fiber is 0.3-15 μm; and / or

[0011] The inorganic porous material is one or more of porous calcium silicate, calcium aluminum titanate, and silicoaluminophosphate molecular sieve.

[0012] Preferably, the inorganic fibers account for 0.5 to 5 wt% of the mixed fiber suspension;

[0013] The amount of the inorganic porous material is 1 to 10 wt % of the inorganic fiber;

[0014] The particle size of the inorganic porous material is 5 to 50 μm; and / or

[0015] The specific surface area of ​​the inorganic porous material is 50 to 300 m 2 / g.

[0016] Preferably, the amount of the foaming agent is 0.1 to 10 wt % of the mixed fiber suspension; preferably, the foaming agent is a surfactant, preferably one or more of sodium dodecyl sulfate (SDS), hexadecyltrimethylammonium bromide (CTAB), cocamidopropyl betaine (CHSB), Tween 80, and polyvinyl alcohol (PVA).

[0017] Preferably, the mixing and foaming is carried out by mechanical stirring or gas injection; and / or

[0018] The foam elimination method is vacuum suction, water spraying or contact pressing.

[0019] Preferably, the mechanical stirring speed is 1000-3000 rpm, and the time is 5-20 min;

[0020] The gas used for injection is air, helium or carbon dioxide, the bubbling time is 30s to 300s, and the bubbling volume is 10 to 100m 3 / h.

[0021] The vacuum degree of the vacuum suction is in the range of 0.01 to 0.1 MPa;

[0022] The pressure of the spray water is 0.1-0.5 MPa; and / or

[0023] The contact pressing pressure is 0.1-0.3 MPa.

[0024] Preferably, the volume of gas in the foam slurry accounts for 50-80%, the average diameter of the foam is 20-200 μm, and the water filtration half-life is 100-400 s.

[0025] Preferably, the drying method is hot air drying or cylinder drying;

[0026] Preferably, the drying temperature is 120-200° C. and the drying time is 60-120 seconds.

[0027] In a second aspect, the present invention provides a lightweight thermal insulation substrate, which is prepared by the preparation method described in the first aspect.

[0028] The present invention provides a lightweight thermal insulation material in a third aspect, comprising a lightweight thermal insulation substrate prepared by the preparation method described in the first aspect or the lightweight thermal insulation substrate described in the second aspect and an aerogel loaded on the lightweight thermal insulation substrate.

[0029] Compared with the prior art, the present invention has at least the following beneficial effects:

[0030] The present invention uses inorganic fibers and inorganic porous materials as main raw materials to prepare lightweight thermal insulation substrates, wherein the inorganic fibers have the advantages of high temperature resistance, strong corrosion resistance and good dimensional stability, and can adapt to extreme high temperature environments, thereby ensuring the integrity of the material in high temperature environments; the inorganic porous materials have the characteristics of high temperature resistance and multiple pores, which further improves the thermal insulation material's loading capacity for aerogel and its tolerant temperature.

[0031] The present invention adds a foaming agent to the slurry for foaming, disperses the fibers in the water-based foam to form a foam slurry, and prepares a lightweight thermal insulation substrate by a foam-molded wet paper sheet method. The fibers are dispersed by using foam instead of water, which can effectively prevent the fibers from entanglement and re-flocculation, while increasing the molding concentration and reducing the waste of water resources. Compared with the traditional wet molding method, the lightweight thermal insulation substrate prepared by the method provided by the present invention has better uniformity, lower density, higher porosity and higher aerogel loading. The thermal insulation material containing the lightweight thermal insulation substrate has both light weight, excellent thermal insulation performance and temperature resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 It is a preparation flow chart of the lightweight thermal insulation substrate provided by the present invention. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0035] In a first aspect, the present invention provides a method for preparing a lightweight thermal insulation substrate, the preparation method comprising the following steps:

[0036] S1. Mixing inorganic fibers, inorganic porous materials and water to obtain a mixed fiber suspension;

[0037] S2. The mixed fiber suspension and the foaming agent are mixed and foamed to obtain a foam slurry;

[0038] S3. The foam slurry is spread and formed to obtain wet paper sheets, and then the foam is eliminated and dried to obtain a lightweight thermal insulation substrate.

[0039] The present invention uses inorganic fibers and inorganic porous materials as main raw materials to prepare lightweight thermal insulation substrates, wherein the inorganic fibers have the advantages of high temperature resistance, strong corrosion resistance and good dimensional stability, and can adapt to extreme high temperature environments, thereby ensuring the integrity of the material in high temperature environments; the inorganic porous materials have the characteristics of high temperature resistance and multiple pores, which further improves the thermal insulation material's loading capacity for aerogel and its tolerant temperature.

[0040] The present invention adds a foaming agent to the slurry for foaming, disperses the fibers in the water-based foam to form a foam slurry, and prepares a lightweight thermal insulation substrate by a foam-molded wet paper sheet method. The fibers are dispersed by using foam instead of water, which can effectively prevent the fibers from entanglement and re-flocculation, while increasing the molding concentration and reducing the waste of water resources. Compared with the traditional wet molding method, the lightweight thermal insulation substrate prepared by the method provided by the present invention has better uniformity, lower density, higher porosity and higher aerogel loading. The thermal insulation material containing the lightweight thermal insulation substrate has both light weight, excellent thermal insulation performance and temperature resistance.

[0041] According to some preferred embodiments, the inorganic fiber is one or more of glass fiber, ceramic fiber, high silica fiber, and quartz fiber. Preferably, the diameter of the inorganic fiber is 0.3 to 15 μm; (for example, it can be 0.3 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm or 15 μm) and / or

[0042] The inorganic porous material is one or more of silicate porous calcium silicate, perovskite calcium aluminum titanate, and aluminosilicate SAPO (silicoaluminophosphate) molecular sieve.

[0043] According to some preferred embodiments, the inorganic fiber accounts for 0.5-5wt% of the mixed fiber suspension (for example, 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt% or 5wt%). The present invention controls the amount of inorganic fiber within the above range to ensure that the inorganic fiber has a higher dispersion concentration in the foam slurry.

[0044] According to some preferred embodiments, the amount of the inorganic porous material is 1 to 10 wt % of the inorganic fiber (for example, 1 wt %, 2 wt %, 3 wt %, 4 wt %, 5 wt %, 6 wt %, 7 wt %, 8 wt %, 9 wt % or 10 wt %).

[0045] According to some preferred embodiments, the particle size of the inorganic porous material is 5 to 50 μm (for example, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm or 50 μm).

[0046] According to some preferred embodiments, the specific surface area of ​​the inorganic porous material is 50 to 300 m 2 / g (for example, it can be 50m 2 / g、100m 2 / g, 150m 2 / g, 200m 2 / g, 250m 2 / g or 300m 2 / g).

[0047] According to some preferred embodiments, the amount of the foaming agent is 0.1 to 10 wt% of the mixed fiber suspension (for example, it can be 0.1 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt% or 10 wt%); preferably, the foaming agent is a surfactant, preferably one or more of anionic surfactant sodium dodecyl sulfate (SDS), cationic surfactant hexadecyltrimethylammonium bromide (CTAB), amphoteric surfactant cocamidopropyl betaine (CHSB), non-ionic surfactant Tween 80 (Tween 80), and polyvinyl alcohol (PVA).

[0048] According to some preferred embodiments, the mixing and foaming is carried out by mechanical stirring or gas injection.

[0049] According to some preferred embodiments, the foam elimination method is vacuum suction, water spraying or contact pressing.

[0050] According to some preferred embodiments, the mechanical stirring speed is 1000-3000 rpm (for example, 1000 rpm, 1500 rpm, 2000 rpm, 2500 rpm or 3000 rpm), and the time is 5-20 min (for example, 5 min, 10 min, 115 min or 20 min).

[0051] According to some preferred embodiments, the gas used for the injection gas is air, helium or carbon dioxide, the bubbling time is 30s to 300s (for example, 30s, 50s, 100s, 150s, 200s, 250s or 300s), and the bubbling volume is 10 to 100m 3 / h (for example, it can be 10m 3 / h、20m 3 / h、30m 3 / h、40m 3 / h、50m 3 / h、60m 3 / h、70m 3 / h、80m 3 / h、90m 3 / h or 100m 3 / h).

[0052] According to some preferred embodiments, the vacuum degree of the vacuum suction is in the range of 0.01 to 0.1 MPa (for example, it may be 0.01 MPa, 0.02 MPa, 0.03 MPa, 0.04 MPa, 0.05 MPa, 0.06 MPa, 0.07 MPa, 0.08 MPa, 0.09 MPa or 0.1 MPa).

[0053] According to some preferred embodiments, the pressure of the spray water is 0.1-0.5 MPa (for example, it may be 0.1 MPa, 0.15 MPa, 0.2 MPa, 0.25 MPa, 0.3 MPa, 0.35 MPa, 0.4 MPa, 0.45 MPa or 0.5 MPa).

[0054] According to some preferred embodiments, the contact pressing pressure is 0.1-0.3 MPa (for example, it may be 0.1 MPa, 0.15 MPa, 0.2 MPa, 0.25 MPa or 0.3 MPa).

[0055] According to some preferred embodiments, the volume of gas in the foam slurry is 50-80% (for example, it can be 50%, 55%, 60%, 65%, 70%, 75% or 80%), the average diameter of the foam is 20-200 μm (for example, it can be 20 μm, 50 μm, 100 μm, 150 μm or 200 μm), and the water filtration half-life is 100-400 s (for example, it can be 100s, 150s, 200s, 250s, 300s, 350s or 400s).

[0056] According to some preferred embodiments, the drying method is hot air drying or cylinder drying;

[0057] Preferably, the drying temperature is 120-200°C (for example, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C or 200°C), and the drying time is 60-120s (for example, 60s, 70s, 80s, 90s, 100s, 110s or 120s).

[0058] In a second aspect, the present invention provides a lightweight thermal insulation substrate, which is prepared by the preparation method described in the first aspect.

[0059] The present invention provides a lightweight thermal insulation material in a third aspect, comprising a lightweight thermal insulation substrate prepared by the preparation method described in the first aspect or the lightweight thermal insulation substrate described in the second aspect and an aerogel loaded on the lightweight thermal insulation substrate.

[0060] In some preferred embodiments of the present invention, the loading amount of the aerogel is not less than 35% of the weight of the lightweight thermal insulation substrate, preferably 35-50%.

[0061] In some preferred embodiments of the present invention, the method for preparing the lightweight thermal insulation material comprises: impregnating the lightweight thermal insulation substrate in an aerogel precursor, performing sol-gel and drying to obtain the lightweight thermal insulation material. The drying is one or more of supercritical drying, freeze drying, and drying at room temperature and pressure.

[0062] In order to more clearly illustrate the technical solutions and advantages of the present invention, the present invention is further described below in conjunction with the examples. The present invention does not specifically limit the sources of the reagents used in the examples and comparative examples, and the reagents can be directly purchased or synthesized by themselves.

[0063] Example 1

[0064] A method for preparing a lightweight thermal insulation substrate comprises:

[0065] (1) Add glass fiber (inorganic fiber) and porous calcium silicate (inorganic porous material) into water and mix and disperse them to obtain a mixed fiber suspension with an inorganic fiber content of 0.5 wt.%, wherein the diameter of the inorganic fiber is 0.3-0.8 μm, the amount of inorganic porous material added is 3% of the mass of the inorganic fiber, the particle size is 25 μm, and the specific surface area (BET) is 100 m 2 / g;

[0066] (2) adding sodium dodecyl sulfate (surfactant) to the mixed fiber suspension, wherein the amount of the surfactant added is 0.1% of the mass of the mixed fiber suspension, and mixing and foaming are performed by mechanical stirring at a stirring speed of 1000 rpm for 5 min to form a foam slurry having a gas volume content of 65%, a foam size of 53 μm, and a water filtration half-life of 180 s;

[0067] (3) The foam slurry is spread and formed to obtain a wet paper sheet, and then the foam is eliminated by vacuum suction, wherein the vacuum suction pressure is 0.03 MPa. Finally, the wet paper sheet is dried at 180° C. for 60 seconds by hot air drying to obtain a lightweight thermal insulation substrate.

[0068] Example 2

[0069] A method for preparing a lightweight thermal insulation substrate comprises:

[0070] (1) Ceramic fiber (inorganic fiber) and calcium aluminum titanate (inorganic porous material) are added into water and mixed and dispersed to obtain a mixed fiber suspension having an inorganic fiber content of 1 wt.%, wherein the diameter of the inorganic fiber is 5 to 10 μm, the amount of the inorganic porous material added is 5% of the mass of the inorganic fiber, the particle size is 5 μm, and the specific surface area (BET) is 50 m 2 / g;

[0071] (2) adding hexadecyltrimethylammonium bromide (surfactant) to the mixed fiber suspension, wherein the amount of the surfactant added is 1% of the mass of the mixed fiber suspension, and mixing and foaming are performed by mechanical stirring at a stirring speed of 3000 rpm for 10 min to form a foam slurry having a gas volume content of 75%, a foam size of 40 μm, and a water filtration half-life of 220 s;

[0072] (3) The foam slurry is spread and formed to obtain a wet paper sheet, and then the foam is eliminated by vacuum suction with a vacuum suction pressure of 0.03 MPa. Finally, the wet paper sheet is dried at 160° C. for 80 seconds by hot air drying to obtain a lightweight thermal insulation substrate.

[0073] Example 3

[0074] A method for preparing a lightweight thermal insulation substrate comprises:

[0075] (1) High silica fiber (inorganic fiber) and SAPO molecular sieve (inorganic porous material) are added into water and mixed and dispersed to obtain a mixed fiber suspension having an inorganic fiber content of 2 wt.%, wherein the diameter of the inorganic fiber is 10 to 15 μm, the amount of inorganic porous material added is 8% of the mass of the inorganic fiber, the particle size is 10 μm, and the specific surface area (BET) is 200 m 2 / g;

[0076] (2) Adding cocamidopropyl betaine (surfactant) to the mixed fiber suspension, wherein the amount of surfactant added is 2% of the mass of the mixed fiber suspension, and injecting air using a foam generator, with a bubbling time of 100 s and a bubbling volume of 30 m 3 / h, forming a foam slurry with a gas volume content of 50%, a foam size of 120μm, and a water filtration half-life of 100s;

[0077] (3) The foam slurry is spread and shaped to obtain a wet paper sheet, and the foam is eliminated by spraying water with a spray water pressure of 0.1 MPa. The wet paper sheet is dried at 120° C. for 80 seconds by a drying cylinder to obtain a lightweight thermal insulation substrate.

[0078] Example 4

[0079] A method for preparing a lightweight thermal insulation substrate comprises:

[0080] (1) Add quartz fiber (inorganic fiber) and porous calcium silicate (inorganic porous material) into water, mix and disperse them, and obtain a mixed fiber suspension with an inorganic fiber content of 3 wt.%, wherein the diameter of the inorganic fiber is 3 to 8 μm, the amount of inorganic porous material added is 2% of the mass of the inorganic fiber, the amount of inorganic porous material added is 3% of the mass of the inorganic fiber, the particle size is 50 μm, and the specific surface area (BET) is 150 m 2 / g

[0081] (2) Tween 80 was added to the mixed fiber suspension in an amount of 10% of the mixed fiber suspension mass, and nitrogen was added using a foam generator with a bubbling time of 100 s and a bubbling volume of 30 m3. 3 / h, forming a foam slurry with a gas volume content of 60%, a foam size of 20μm, and a water filtration half-life of 350s;

[0082] (3) The foam slurry is spread and shaped to obtain a wet paper sheet, and the foam is eliminated by spraying water with a spray water pressure of 0.5 MPa. The wet paper sheet is dried at 200° C. for 120 seconds by a drying cylinder to obtain a lightweight thermal insulation substrate.

[0083] Example 5

[0084] The method is basically the same as Example 1, except that in step (1), the content of inorganic fibers in the mixed fiber suspension is 5 wt.%.

[0085] Example 6

[0086] The method is basically the same as Example 1, except that in step (2), the surfactant is polyvinyl alcohol.

[0087] Example 7

[0088] The method is basically the same as Example 1, except that in step (3), the foam is eliminated by spraying water, and the spraying water pressure is 0.1 MPa.

[0089] Example 8

[0090] The method is basically the same as Example 1, except that in step (1), the amount of inorganic porous material added is 10% of the mass of the inorganic fiber.

[0091] Example 9

[0092] The method is basically the same as Example 1, except that in step (1), the particle size of the inorganic porous material is 25 μm, and the specific surface area (BET) is 300 m 2 / g.

[0093] Comparative Example 1

[0094] (1) adding glass fiber (inorganic fiber) into water, mixing and dispersing, and obtaining a fiber suspension having a glass fiber (inorganic fiber) content of 0.5 wt.%;

[0095] (2) The fiber suspension is pulped and formed to obtain a wet paper sheet, which is dehydrated by vacuum suction at a vacuum suction pressure of 0.03 MPa. The wet paper sheet is dried at 180° C. for 60 seconds by hot air drying to obtain a thermal insulation material.

[0096] Comparative Example 2

[0097] (1) adding plant fiber (coniferous wood fiber) into water and mixing and dispersing to obtain a mixed fiber suspension having a plant fiber content of 0.5 wt.%;

[0098] (2) The fiber suspension is pulped and formed to obtain a wet paper sheet, which is dehydrated by vacuum suction at a vacuum suction pressure of 0.03 MPa. The wet paper sheet is dried at 180° C. for 60 seconds by hot air drying to obtain a lightweight thermal insulation substrate.

[0099] It should be noted that the inventors have found that the performance of lightweight thermal insulation substrates made from other plant fibers, such as hardwood fibers, hemp fibers, bamboo fibers, cellulose fibers, etc., is not much different from that of coniferous wood fibers, and they are not listed here one by one.

[0100] Comparative Example 3

[0101] The method is basically the same as Example 1, except that in step (1), the inorganic porous material porous calcium silicate is not added.

[0102] Comparative Example 4

[0103] The method is basically the same as Example 1, except that in step (1), hydrated calcium silicate is used instead of porous calcium silicate.

[0104] The lightweight thermal insulation substrate and lightweight thermal insulation material (hereinafter referred to as sample) prepared in the examples and comparative examples were subjected to performance tests. The test results are shown in Table 1.

[0105] Performance testing of lightweight thermal insulation substrates

[0106] Density test method: Cut the sample into 100mm×100mm specimens, dry at 105℃±2℃ for 2h, then cool in a dryer to room temperature, weigh the sample mass, measure the sample thickness with a thickness gauge, and calculate the sample quantitative density according to the quantitative calculation formula G=m / (l·b·d); where G is the sample quantitative density, m is the sample mass, l is the sample length, b is the sample width, and d is the sample thickness.

[0107] Thermal conductivity: The thermal conductivity is tested by heat flow meter method, and the test method refers to GB / T 10295-2008

[0108] Evenness index: tested by a paper dust evenness instrument, the test method refers to GB / T 1541-2007;

[0109] Porosity: The porosity is tested by the bubble method, and the test method refers to HY / T 039-1995

[0110] Performance testing of lightweight thermal insulation materials

[0111] Preparation of lightweight thermal insulation material: The lightweight thermal insulation substrate prepared in each embodiment is immersed in a silica aerogel precursor solution (wherein methyl orthosilicate accounts for 20% of the mass of the aerogel composite material based on the mass of silica), and a lightweight thermal insulation material is obtained through sol-gel and drying.

[0112] Aerogel loading rate: The aerogel loading rate is calculated using the density ratio method. In aerogel composites, the loading rate can be calculated by the density ratio of aerogel to composite aerogel:

[0113] Where M is the mass of the material after loading aerogel, and m is the mass of the material before loading aerogel.

[0114] Loss on ignition: Use a guillotine or scissors to cut 1.5-2g (accurate to 0.0001g) of sample, put it in a constant temperature box at 100-105℃ and dry it for 1h, take it out and put it in a desiccator, cool it to room temperature (25-28℃) and weigh it, and then dry it for 30min and weigh it until the mass is constant, which is recorded as m 0 ; Place the sample with constant mass in a muffle furnace at 650℃ and burn for 1h, take it out and put it in a dryer, cool it to room temperature and weigh it, and then dry it for 30min and weigh it until the mass is constant, recorded as m; the loss on ignition is calculated by the following formula:

[0115]

[0116] Table 1. Performance data of lightweight thermal insulation substrates and lightweight thermal insulation materials prepared in Examples and Comparative Examples

[0117]

[0118]

[0119] It should be noted that the aerogel loading rate in the table refers to the mass fraction of aerogel in the lightweight thermal insulation substrate. As can be seen from Table 1, the lightweight thermal insulation substrate prepared in the embodiment of the present invention has lower density and thermal conductivity, higher porosity and aerogel loading rate, and the lightweight thermal insulation material obtained after loading aerogel has lower thermal conductivity, better heat resistance, and a long-term heat resistance temperature of up to 650°C.

[0120] Compared with Example 1, the thermal insulation substrates prepared in Comparative Example 1 by using a traditional wet molding method without adding inorganic porous materials and in Comparative Example 2 by using plant fibers without adding inorganic porous materials and using a traditional wet molding method have significantly increased density, significantly reduced aerogel loading rate, and significantly increased thermal conductivity of the thermal insulation material finally obtained, and deteriorated thermal insulation performance; Comparative Example 2 uses plant fibers, resulting in poor temperature resistance of the thermal insulation material containing the substrate prepared therefrom.

[0121] Compared with Example 1, the aerogel loading rate of the thermal insulation substrate prepared in Comparative Example 3 without adding the inorganic porous material was reduced by 15%, and the thermal conductivity was also increased, resulting in poor thermal insulation performance.

[0122] Compared with Example 1, the inorganic granular material hydrated calcium silicate used in Comparative Example 4 has fewer pores and cannot fully adsorb aerogel, resulting in a 12.5% ​​reduction in the aerogel loading rate of the prepared thermal insulation substrate, resulting in a significant increase in the thermal conductivity of the final lightweight thermal insulation material and a deterioration in the thermal insulation performance.

[0123] In summary, compared with the traditional aqueous wet molding method, the thermal insulation substrate prepared by the preparation method of the present invention has a lower density and a higher aerogel loading rate, and the thermal insulation material finally obtained has both light weight and excellent thermal insulation performance.

[0124] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a lightweight thermal insulation substrate, characterized in that: The preparation method comprises the following steps: S1. Mixing inorganic fibers, inorganic porous materials and water to obtain a mixed fiber suspension; S2. The mixed fiber suspension and the foaming agent are mixed and foamed to obtain a foam slurry; S3. The foam slurry is spread and formed to obtain wet paper sheets, and then the foam is eliminated and dried to obtain a lightweight thermal insulation substrate.

2. The preparation method according to claim 1, characterized in that: The inorganic fiber is one or more of glass fiber, ceramic fiber, high silica fiber, and quartz fiber. Preferably, the inorganic fiber has a diameter of 0.3 to 15 μm; and / or The inorganic porous material is one or more of porous calcium silicate, calcium aluminum titanate, and silicoaluminophosphate molecular sieve.

3. The preparation method according to claim 1 or 2, characterized in that: The inorganic fibers account for 0.5 to 5 wt% of the mixed fiber suspension; The amount of the inorganic porous material is 1 to 10 wt % of the inorganic fiber; The particle size of the inorganic porous material is 5 to 50 μm; and / or The specific surface area of ​​the inorganic porous material is 50 to 300 m 2 / g.

4. The preparation method according to claim 1, characterized in that: The amount of the foaming agent is 0.1-10wt% of the mixed fiber suspension; preferably, the foaming agent is a surfactant, preferably one or more of sodium dodecyl sulfate, hexadecyltrimethylammonium bromide, cocamidopropyl betaine, Tween 80, and polyvinyl alcohol.

5. The preparation method according to claim 1, characterized in that: The mixing and foaming is carried out by mechanical stirring or gas injection; and / or The foam elimination method is vacuum suction, water spraying or contact pressing.

6. The preparation method according to claim 5, characterized in that: The mechanical stirring speed is 1000-3000 rpm, and the time is 5-20 min; The gas used for injection is air, helium or carbon dioxide, the bubbling time is 30s to 300s, and the bubbling volume is 10 to 100m 3 / h; The vacuum degree of the vacuum suction is in the range of 0.01 to 0.1 MPa; The pressure of the spray water is 0.1-0.5 MPa; and / or The contact pressing pressure is 0.1-0.3 MPa.

7. The preparation method according to claim 1, characterized in that: The volume of gas in the foam slurry accounts for 50-80%, the average diameter of the foam is 20-200 μm, and the water filtration half-life is 100-400 seconds.

8. The preparation method according to claim 1, characterized in that: The drying method is hot air drying or drying cylinder drying; Preferably, the drying temperature is 120-200° C. and the drying time is 60-120 seconds.

9. A lightweight thermal insulation substrate, characterized in that: The method is prepared by the method according to any one of claims 1 to 8.

10. A lightweight thermal insulation material, characterized in that: It comprises a lightweight thermal insulation substrate prepared by the preparation method according to any one of claims 1 to 8 or the lightweight thermal insulation substrate according to claim 9 and an aerogel loaded on the lightweight thermal insulation substrate.

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