Lightweight compression-resistant three-dimensional woven spacer fabric reinforced aerogel thermal insulation material and preparation method thereof

Abstract

The invention provides a lightweight compression-resistant three-dimensional woven spacer fabric reinforced aerogel thermal insulation material and a preparation method thereof.The preparation method comprises the steps that a three-dimensional woven spacer fabric is fully soaked with silica sol and then subjected to thermocuring, and a three-dimensional woven spacer fabric framework structure is formed through multiple times of soaking-thermocuring shaping; putting the shaped skeleton structure into an aerogel precursor solution, and then carrying out gelation, so that the precursor solution gradually forms gel in the skeleton structure; and removing the solvent in the gel in the skeleton structure to obtain the three-dimensional woven spacer fabric reinforced aerogel thermal insulation material. The thermal insulation material is prepared by compounding the pre-shaped spacer fabric skeleton and the aerogel, and has the excellent properties of light weight, compression resistance and efficient thermal insulation.

Description

Technical Field

[0001] The present invention belongs to the technical field of aerogel insulation materials, and particularly relates to a lightweight, compressive, three-dimensional woven spacer fabric reinforced aerogel insulation material and a preparation method thereof, which can be applied to fields such as aerospace, military industry, and construction that require heat-resistant performance. Background Art

[0002] In scenarios such as aerospace, high-speed aircraft re-entry into the atmosphere, and thermal protection of military equipment, high-performance thermal protection materials are needed, which require them to have both thermal insulation and load-bearing functional and structural integrated properties. Traditional thermal protection materials often have some shortcomings. For example, the mechanical properties of single aerogel materials are poor, and they are prone to cracking and powdering during use; and ordinary fabric-reinforced composite materials are difficult to achieve excellent thermal insulation properties while ensuring mechanical properties. Three-dimensional spacer fabrics have unique structural advantages, and it is expected that combining them with aerogels can produce thermal protection composite materials with excellent comprehensive performance. However, the mechanical properties of the three-dimensional spacer fabric-reinforced aerogel thermal insulation materials reported so far are generally poor, and the compressive strength is usually less than 1MPa, which makes it difficult to meet the application requirements of lightweight thermal insulation and structural load-bearing integrated materials. Summary of the Invention

[0003] In order to overcome the deficiencies in the prior art, the inventors have conducted intensive research and provided a lightweight, pressure-resistant three-dimensional woven spacer fabric reinforced aerogel thermal insulation material and a preparation method thereof. The thermal insulation material is prepared by compounding a pre-shaped spacer fabric skeleton with aerogel. The thermal insulation material has excellent properties of being lightweight, pressure-resistant, and highly efficient in thermal insulation. Different numbers of spacer layers, different spacer layer thicknesses, and different aerogel densities can be designed according to the requirements of thermal protection performance. The material is suitable for use in aviation, aerospace, shipbuilding, construction, and other fields.

[0004] The technical solutions provided by the present invention are as follows:

[0005] In a first aspect, a method for preparing a lightweight, compressive-resistant three-dimensional woven spacer fabric reinforced aerogel thermal insulation material comprises the following steps:

[0006] The three-dimensional woven spacer fabric is fully impregnated with silica sol, and then heat-cured. The three-dimensional woven spacer fabric skeleton structure is formed through multiple impregnation-heat-curing processes.

[0007] The shaped skeleton structure is placed in an aerogel precursor solution, and then gelled, so that the precursor solution gradually forms a gel inside the skeleton structure;

[0008] The solvent in the gel inside the skeleton structure is removed to obtain a three-dimensional woven spacer fabric reinforced aerogel thermal insulation material.

[0009] In a second aspect, a lightweight, compressive, three-dimensional woven spacer fabric reinforced aerogel thermal insulation material is prepared by the method for preparing a lightweight, compressive, three-dimensional woven spacer fabric reinforced aerogel thermal insulation material according to the first aspect.

[0010] The lightweight, compressive-resistant three-dimensional woven spacer fabric reinforced aerogel thermal insulation material and its preparation method provided by the present invention have the following beneficial effects:

[0011] (1) The present invention provides a lightweight, pressure-resistant three-dimensional woven spacer fabric reinforced aerogel thermal insulation material and a preparation method thereof. The thermal insulation material is prepared by compounding a pre-shaped spacer fabric skeleton with aerogel. The prepared thermal insulation material has both excellent thermal insulation performance and pressure resistance. The filling of aerogel gives the thermal insulation material good thermal insulation performance, can effectively block heat transfer, and meet the thermal insulation requirements. The reinforced three-dimensional spacer fabric provides a high-strength support structure for the thermal insulation material, overcoming the problem of poor mechanical properties of aerogel, making the material less susceptible to damage when subjected to external forces.

[0012] (2) The present invention provides a lightweight, compressive, three-dimensional woven spacer fabric reinforced aerogel thermal insulation material and a preparation method thereof. The three-dimensional woven spacer fabric is reinforced and shaped using silica sol, and the three-dimensional woven spacer fabric is filled with SiO2 aerogel. The shaping material and the filler are both SiO2 materials. Not only does it have excellent thermal insulation performance, but the bonding performance between the three-dimensional woven spacer fabric and the filler is also excellent.

[0013] (3) The present invention provides a lightweight, compressive, three-dimensional woven spacer fabric reinforced aerogel thermal insulation material and a preparation method thereof. The prepared thermal insulation material is highly customizable and can be customized to have different heat-resistant and mechanical properties by changing the fiber type, number of spacer layers, and type and performance parameters of the aerogel according to different application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Lightweight, compressive 3D woven spacer fabric reinforced with aerogel insulation. DETAILED DESCRIPTION

[0015] The following detailed description of the present invention will make the features and advantages of the present invention more clear and explicit.

[0016] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0017] The present invention provides a method for preparing a lightweight, compressive-resistant three-dimensional woven spacer fabric reinforced aerogel thermal insulation material, comprising the following steps:

[0018] Step (1): using a three-dimensional loom to weave a three-dimensional spacer fabric.

[0019] In this step, the three-dimensional woven spacer fabric can be a single-layer or multi-layer spacer fabric structure according to different heat protection performance requirements.

[0020] The single-layer spacer fabric comprises an upper surface layer, a lower surface layer and a spacer layer in the middle. The spacer yarns in the spacer layer are interwoven with the weft yarns between the upper surface layer and the lower surface layer to weave the upper surface layer and the lower surface layer into a whole.

[0021] The multi-layer spacer fabric includes an upper surface layer, a lower surface layer, an intermediate layer and a multi-layer spacer layer in the middle; the spacer layer is formed by interweaving the spacer yarn therein with the weft yarns of the adjacent upper and lower layers, and the spacer yarn connects the adjacent layers to form an overall fabric structure. Figure 1 A three-dimensional double-layer spacer fabric is shown.

[0022] The structure of the upper and lower surface layers of the three-dimensional woven spacer fabric can be designed into plain, twill or satin weave according to needs.

[0023] Step (2) is to fully impregnate the three-dimensional woven spacer fabric with silica sol, then perform heat curing, and shape it through multiple "impregnation-heat curing" steps to form a three-dimensional woven spacer fabric skeleton structure.

[0024] In this step, the silica sol is a dispersion of nano-sized SiO2 particles in water or other solvents with a certain viscosity, and the content of SiO2 particles in the silica sol is 30 wt.% to 50 wt.%.

[0025] In this step, the fabric is shaped by multiple "impregnation-heat curing" steps. The number of impregnation steps is determined according to the structure of the fabric and the state of the silica sol, preferably 3 to 8 times, with each vacuum impregnation lasting 20 to 40 minutes. The heat curing temperature is 500 to 800° C., and the time is 3 to 5 hours.

[0026] The three-dimensional woven spacer fabric skeleton is pre-shaped with silica sol, which improves the compressive resistance of the insulation material while ensuring the thermal insulation performance of the material; subsequently, SiO2 aerogel is used to fill the three-dimensional woven spacer fabric. The shaping material and filler are both SiO2 materials, which not only has excellent thermal insulation performance, but also has excellent bonding performance between the three-dimensional woven spacer fabric and the filler.

[0027] Step (3) is to place the skeleton structure into an aerogel precursor solution, and then perform gelation under a set temperature and humidity environment, so that the precursor solution gradually forms a gel inside the skeleton structure.

[0028] In this step, the aerogel precursor solution is a SiO2 aerogel precursor solution.

[0029] In this step, the aerogel precursor solution can be prepared by dissolving a silicon source in a solvent, adding a catalyst, and precisely controlling the ratio of each component to obtain the desired aerogel precursor solution. The silicon source includes, but is not limited to, ethyl orthosilicate; the solvent includes, but is not limited to, ethanol; and the catalyst includes, but is not limited to, aqueous ammonia or hydrochloric acid.

[0030] In this step, the temperature and humidity environment are set as follows: temperature is 30-60° C., and relative humidity is 60%-65%.

[0031] Step (4) is to remove the solvent in the gel by supercritical drying or freeze drying.

[0032] In this step, the conditions of the supercritical drying method are: supercritical drying temperature is 30-60° C., pressure is 8-20 MPa, time is more than 1 hour, and carbon dioxide flow rate is about 1-5 L / min.

[0033] In this step, the freeze-drying conditions are as follows: freezing temperature is -20 to -100°C for 2 to 48 hours, then gradually heating to 0 to 20°C, and continuing drying under vacuum for 12 to 48 hours until the gel is completely freeze-dried.

[0034] The present invention also provides a lightweight, compressive-resistant three-dimensional woven spacer fabric reinforced aerogel thermal insulation material, which is prepared by the above-mentioned method for preparing a lightweight, compressive-resistant three-dimensional woven spacer fabric reinforced aerogel thermal insulation material.

[0035] Example

[0036] Example 1

[0037] A method for preparing a lightweight, compressive-resistant three-dimensional woven spacer fabric reinforced aerogel thermal insulation material comprises the following steps:

[0038] Glass fiber is used as raw material, and a three-dimensional woven double-layer spacer fabric is woven using a three-dimensional loom. The structural diagram is shown in the figure. Figure 1 As shown, the upper and lower layers of the fabric are both plain weaves, the surface layer glass fiber yarn density is 10 yarns / cm, the length of the upper and lower layer spacer yarns is 5 mm, and the spacing of the spacer yarns on the plane is 10 mm × 10 mm.

[0039] After fully impregnating the fabric with silica sol (SiO2 content of 30wt.%), heat-curing at 500℃ for 4 hours, cooling and impregnating it with silica sol again, and then continuing to cure under the above conditions, the cycle was repeated three times to achieve the predetermined shape of the fabric.

[0040] Tetraethyl orthosilicate (TES) was selected as the precursor for the SiO2 aerogel, with ethanol as the solvent and hydrochloric acid as the catalyst. The molar ratio of TES, ethanol, and hydrochloric acid was 1:5:0.01. An appropriate amount of methyltrimethoxysilane was added as a modifier, with a molar ratio of 0.1:1 to TES. The mixture was stirred at 300 rpm at 25°C for 2 hours to ensure thorough mixing.

[0041] The shaped three-dimensional spacer fabric was immersed in the SiO2 aerogel precursor solution for 6 hours. The impregnated fabric was then subjected to a gelation reaction at 40°C and 60% relative humidity for 24 hours. Supercritical drying was then performed using carbon dioxide as the supercritical fluid at 40°C, 10 MPa, and a carbon dioxide flow rate of 1 L / min for 12 hours to produce a three-dimensional woven double-layer glass fiber spacer fabric-reinforced silica aerogel thermal insulation material.

[0042] Tests have shown that the compressive strength of the three-dimensional woven double-layer glass fiber spacer fabric reinforced silica aerogel insulation material is 3.5 MPa and the thermal conductivity is 0.034 W / (m·K); the bonding strength between the three-dimensional woven spacer fabric and SiO2 aerogel is 7.1 MPa.

[0043] Comparative Example 1

[0044] Compared with Example 1, this comparative example did not perform the "multiple immersion and heat curing" process of the fabric in the silica sol. The specific preparation process includes the following steps:

[0045] Glass fiber is used as raw material, and a three-dimensional woven double-layer spacer fabric is woven using a three-dimensional loom. The structural diagram is shown in the figure. Figure 1 As shown, the upper and lower layers of the fabric are both plain weaves, the surface layer glass fiber yarn density is 10 yarns / cm, the length of the upper and lower layer spacer yarns is 5 mm, and the spacing of the spacer yarns on the plane is 10 mm × 10 mm.

[0046] Tetraethyl orthosilicate (TES) was selected as the precursor for the SiO2 aerogel, with ethanol as the solvent and hydrochloric acid as the catalyst. The molar ratio of TES, ethanol, and hydrochloric acid was 1:5:0.01. An appropriate amount of methyltrimethoxysilane was added as a modifier, with a molar ratio of 0.1:1 to TES. The mixture was stirred at 300 rpm at 25°C for 2 hours to ensure thorough mixing.

[0047] The three-dimensional spacer fabric was immersed in the SiO2 aerogel precursor solution for 6 hours. The impregnated fabric was then subjected to a gelation reaction at 40°C and 60% relative humidity for 24 hours. Supercritical drying was then performed using carbon dioxide as the supercritical fluid at 40°C, 10 MPa, and a carbon dioxide flow rate of 1 L / min for 12 hours to produce a three-dimensional woven double-layer glass fiber spacer fabric-reinforced silica aerogel thermal insulation material.

[0048] After testing, the compressive strength of the three-dimensional woven double-layer glass fiber spacer fabric reinforced silica aerogel insulation material prepared by the method of Comparative Example 1 was 0.36 MPa, and the thermal conductivity was 0.035 W / (m·K); the bonding strength between the three-dimensional woven spacer fabric and the SiO2 aerogel was 0.7 MPa.

[0049] Example 2

[0050] A method for preparing a lightweight, compressive-resistant three-dimensional woven spacer fabric reinforced aerogel thermal insulation material comprises the following steps:

[0051] Quartz fiber is used as the raw material, and a plain weave is used to weave the upper and lower layers of the fabric. The upper and lower layers of the fabric are plain weave. The quartz fiber yarn density of the fabric surface is 10 yarns / cm, the spacer yarn length is 6mm, and the spacing of the spacer yarns on the plane is 12mm×12mm.

[0052] After fully impregnating the fabric with silica sol (SiO2 content of 40wt.%), heat curing was carried out at 600℃ for 4 hours, and then impregnated with silica sol again after cooling, and then continued to cure under the above conditions. This cycle was repeated four times to achieve the predetermined shape of the fabric.

[0053] Tetraethyl orthosilicate (TES) was selected as the precursor for SiO2 aerogel, with ethanol as the solvent and ammonia as the catalyst. The molar ratio of TES, ethanol, and ammonia (calculated as ammonia) was 1:4:0.1. An appropriate amount of dimethyldiethoxysilane (DDS) was added as a modifier, with a molar ratio of 0.1:1 to TES. The mixture was stirred at 300 rpm at 25°C for 2 hours to ensure thorough mixing.

[0054] The shaped three-dimensional double-layer spacer fabric was placed in the SiO2 aerogel precursor solution and immersed for 6 hours. The impregnated fabric was subjected to a gelation reaction at 40°C and 60% relative humidity for 24 hours. After gelation, it was washed with deionized water for two days, immersed in anhydrous ethanol for two days, and then pre-frozen at -70°C for 4 hours. It was then vacuum freeze-dried at -100°C for 36 hours at a pressure of -200 Pa. The temperature was then gradually increased to 10°C and vacuum dried for another 24 hours to produce a three-dimensional woven double-layer quartz fiber spacer fabric-reinforced silica aerogel thermal insulation material.

[0055] Tests have shown that the compressive strength of the three-dimensional woven double-layer carbon fiber spacer fabric reinforced silica aerogel insulation material is 3.4 MPa, and the thermal conductivity is 0.036 W / (m·K); the bonding strength between the three-dimensional woven spacer fabric and SiO2 aerogel is 7.3 MPa.

[0056] Comparative Example 2

[0057] Compared with Example 2, this comparative example only performs one impregnation of the fabric in silica sol and subsequent thermal curing process. The specific preparation process includes the following steps:

[0058] Quartz fiber is used as the raw material, and a plain weave is used to weave the upper and lower layers of the fabric. The upper and lower layers of the fabric are plain weave. The quartz fiber yarn density of the fabric surface is 10 yarns / cm, the spacer yarn length is 6mm, and the spacing of the spacer yarns on the plane is 12mm×12mm.

[0059] After the fabric is fully impregnated with silica sol (SiO2 content of 40wt.%), it is thermally cured at 600℃ for 4 hours to achieve pre-setting of the fabric.

[0060] Tetraethyl orthosilicate (TES) was selected as the precursor for SiO2 aerogel, with ethanol as the solvent and ammonia as the catalyst. The molar ratio of TES, ethanol, and ammonia (calculated as ammonia) was 1:4:0.1. An appropriate amount of dimethyldiethoxysilane (DDS) was added as a modifier, with a molar ratio of 0.1:1 to TES. The mixture was stirred at 300 rpm at 25°C for 2 hours to ensure thorough mixing.

[0061] The shaped three-dimensional double-layer spacer fabric was placed in the SiO2 aerogel precursor solution and immersed for 6 hours. The impregnated fabric was subjected to a gelation reaction at 40°C and 60% relative humidity for 24 hours. After gelation, it was washed with deionized water for two days, immersed in anhydrous ethanol for two days, and then pre-frozen at -70°C for 4 hours. It was then vacuum freeze-dried at -100°C for 36 hours at a pressure of -200 Pa. The temperature was then gradually increased to 10°C and vacuum dried for another 24 hours to produce a three-dimensional woven double-layer quartz fiber spacer fabric-reinforced silica aerogel thermal insulation material.

[0062] After testing, the compressive strength of the three-dimensional woven double-layer carbon fiber spacer fabric reinforced silica aerogel insulation material prepared by the method of Comparative Example 2 was 0.86 MPa, and the thermal conductivity was 0.032 W / (m·K); the bonding strength between the three-dimensional woven spacer fabric and the SiO2 aerogel was 3.2 MPa.

[0063] Comparative Example 3

[0064] Compared with Example 2, the reinforcement skeleton in this comparative example is formed by impregnating and heat-curing the spacer fabric with polyimide resin. The specific preparation process includes the following steps:

[0065] Quartz fiber is used as the raw material, and a plain weave is used to weave the upper and lower layers of the fabric. The upper and lower layers of the fabric are plain weave. The quartz fiber yarn density of the fabric surface is 10 yarns / cm, the spacer yarn length is 6mm, and the spacing of the spacer yarns on the plane is 12mm×12mm.

[0066] After the fabric is fully impregnated with polyimide resin, it is thermally cured to achieve pre-setting of the fabric.

[0067] Tetraethyl orthosilicate (TES) was selected as the precursor for SiO2 aerogel, with ethanol as the solvent and ammonia as the catalyst. The molar ratio of TES, ethanol, and ammonia (calculated as ammonia) was 1:4:0.1. An appropriate amount of dimethyldiethoxysilane (DDS) was added as a modifier, with a molar ratio of 0.1:1 to TES. The mixture was stirred at 300 rpm at 25°C for 2 hours to ensure thorough mixing.

[0068] The shaped three-dimensional double-layer spacer fabric was placed in the SiO2 aerogel precursor solution and immersed for 6 hours. The impregnated fabric was subjected to a gelation reaction at 40°C and 60% relative humidity for 24 hours. After gelation, it was washed with deionized water for two days, immersed in anhydrous ethanol for two days, and then pre-frozen at -70°C for 4 hours. It was then vacuum freeze-dried at -100°C for 36 hours at a pressure of -200 Pa. The temperature was then gradually increased to 10°C and vacuum dried for another 24 hours to produce a three-dimensional woven double-layer quartz fiber spacer fabric-reinforced silica aerogel thermal insulation material.

[0069] After testing, the compressive strength of the three-dimensional woven double-layer quartz fiber spacer fabric reinforced silica aerogel insulation material prepared by the method of Comparative Example 3 was 4.9 MPa, and the thermal conductivity was 0.079 W / (m·K); the bonding strength between the three-dimensional woven spacer fabric and the SiO2 aerogel was 1.8 MPa.

[0070] The present invention has been described in detail above with reference to specific embodiments and exemplary examples, but these descriptions should not be construed as limiting the present invention. Those skilled in the art will appreciate that, without departing from the spirit and scope of the present invention, various equivalent substitutions, modifications or improvements may be made to the technical solutions and implementations of the present invention, all of which fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

[0071] shall prevail.

[0072] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A method for preparing a lightweight, compressive, three-dimensional woven spacer fabric reinforced aerogel thermal insulation material, characterized in that: The steps include: The three-dimensional woven spacer fabric is fully impregnated with silica sol, and then heat-cured. The three-dimensional woven spacer fabric skeleton structure is formed through multiple impregnation-heat-curing processes. The shaped skeleton structure is placed in an aerogel precursor solution, and then gelled, so that the precursor solution gradually forms a gel inside the skeleton structure; The solvent in the gel inside the skeleton structure is removed to obtain a three-dimensional woven spacer fabric reinforced aerogel thermal insulation material.

2. The method for preparing a lightweight, compressive-resistant three-dimensional woven spacer fabric reinforced aerogel thermal insulation material according to claim 1, characterized in that: The three-dimensional woven spacer fabric is a single-layer or multi-layer spacer fabric structure, and the weave structure of the upper surface layer and the lower surface layer is plain weave, twill weave or satin weave.

3. The method for preparing a lightweight, compressive-resistant three-dimensional woven spacer fabric reinforced aerogel thermal insulation material according to claim 1, characterized in that: The content of SiO2 particles in the silica sol is 30 wt.% to 50 wt.%.

4. The method for preparing a lightweight, compressive-resistant three-dimensional woven spacer fabric reinforced aerogel thermal insulation material according to claim 1, characterized in that: The number of times of multiple dipping and heat curing is 3 to 8 times, and each vacuum dipping is 20 to 40 minutes; the heat curing temperature is 500 to 800° C., and the time is 3 to 5 hours.

5. The method for preparing a lightweight, compressive-resistant three-dimensional woven spacer fabric reinforced aerogel thermal insulation material according to claim 1, characterized in that: The aerogel precursor solution is a SiO2 aerogel precursor solution.

6. The method for preparing a lightweight, compressive-resistant three-dimensional woven spacer fabric reinforced aerogel thermal insulation material according to claim 1, characterized in that: The aerogel precursor solution includes a silicon source, a catalyst, a modifier and a solvent. The silicon source is ethyl orthosilicate, the catalyst is ammonia water or hydrochloric acid, the modifier is methyltrimethoxysilane or dimethyldiethoxysilane, and the solvent is ethanol.

7. The method for preparing a lightweight, compressive-resistant three-dimensional woven spacer fabric reinforced aerogel thermal insulation material according to claim 1, characterized in that: The gelation temperature is 30-60° C., and the relative humidity is 60%-65%.

8. The method for preparing a lightweight, compressive-resistant three-dimensional woven spacer fabric reinforced aerogel thermal insulation material according to claim 1, characterized in that: The removal of the solvent in the gel inside the skeleton structure adopts a supercritical drying or freeze drying method.

9. The method for preparing a lightweight, compressive-resistant three-dimensional woven spacer fabric reinforced aerogel thermal insulation material according to claim 1, characterized in that: The supercritical drying conditions are as follows: the supercritical drying temperature is 30-60°C, the pressure is 8-20 MPa, the time is more than 1 hour, and the carbon dioxide flow rate is 1-5 L / min; The freeze-drying conditions are as follows: freezing temperature is -20 to -100°C for 2 to 48 hours, then gradually heating to 0 to 20°C, and continuing drying under vacuum for 12 to 48 hours until the gel is completely freeze-dried.

10. A lightweight, compressive, three-dimensional woven spacer fabric reinforced aerogel thermal insulation material, characterized in that: The aerogel thermal insulation material is prepared by the preparation method of a lightweight, compression-resistant three-dimensional woven spacer fabric reinforced aerogel thermal insulation material according to any one of claims 1 to 9.

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