Composite material comprising aerogel particles

Abstract

The invention relates to a composite material comprising two or more layers, said composite material comprising a layer (LA) having a thickness of 0.1 to 4 mm mainly comprising aerogel particles having a diameter of 0.1 to 4 mm prior to any compression, and an adjacent adhesive layer (LB) having a thickness of 0.01 to 1 mm, optionally a support layer (LC) having a thickness of 0.01 to 3 mm adjacent to the adhesive layer, the aerogel particle layer (LA) comprises a layer portion (LA-1) having a thickness of 0.01 to 1 mm, said layer portion (LA-1) comprising both the binder and the aerogel particles, and optionally comprising a portion of the support layer (LC), and being positioned adjacent to the binder layer (LB), and wherein the layer portion (LA-1) comprises a portion of the support layer (LC), optionally on the other side of the particle layer (LA), and wherein the aerogel particle layer (LA) comprises a layer portion (LA-1) having a thickness of 0.01 to 1 mm, said layer portion (LA-1) comprising both the binder and the aerogel particles, and optionally comprising a portion of the support layer (LC), and is positioned adjacent to the binder layer (LB). And wherein the aerogel particle layer (LA) further comprises a binder-free layer portion (LA-2) having a thickness equal to or greater than 0.05 mm. The invention also relates to a method for preparing the composite material. And the use of the composite material according to the invention as an insulation material for buildings and constructions, appliances, temperature-controlled logistics, low-temperature applications, automotive applications, infrastructure applications, offshore applications, oil and gas applications or garments, or as a heat shield material in batteries or as a material for preventing heat propagation.

Description

[0001] The present invention relates to a composite material comprising two or more layers, comprising a layer (LA) of thickness 0.1 to 4 mm, primarily comprising aerogel particles having a diameter of 0.1 to 4 mm before any compression, and an adjacent adhesive layer (LB) of thickness 0.01 to 1 mm, optionally adjacent to the adhesive layer (LB) and on its opposite side a support layer or cover layer (LC) of thickness 0.01 to 3 mm, optionally located on the opposite side of the aerogel particle layer (LA), a second adjacent adhesive layer (LB'), and a support layer or cover layer (LC'), wherein the aerogel particle layer (LA) comprises a layer portion (LA-1) of thickness 0.01 to 1 mm, the layer portion (LA-1) comprising both the adhesive and the aerogel particles, and optionally comprising a portion of the support layer (LC) and located adjacent to the adhesive layer (LB), and wherein the aerogel particle layer (LA) further comprises a layer portion (LA-2) without adhesive and having a thickness equal to or greater than 0.05 mm. The present invention also relates to a method for preparing the composite material, and the use of the composite material of the present invention as a thermal insulation material for buildings and constructions, appliances, thermologistics, cryogenic applications, automotive applications, infrastructure applications, marine applications, oil and gas applications or clothing, or as a thermal shield material in batteries or a material that prevents heat transfer.

[0002] Aerogel materials are known in the prior art for their superior thermal insulation properties. Commercial aerogel materials are used as superior thermal insulation materials, for example, in structures and transportation.

[0003] Currently, almost all commercially available aerogel materials are based on inorganic silica aerogels, existing in the form of aerogel fiber blankets, aerogel particles, or aerogel powders. Aerogels typically require hydrophobication treatment, such as using silane additives, to achieve sufficient water and moisture resistance for application. Inorganic silica aerogels (especially when dried using supercritical carbon dioxide) and particularly hydrophobic silica aerogels suffer from poor mechanical strength and integrity, leading to the generation and release of dust during all stages of use, including transportation, installation, use, and disposal. Dust release makes the handling and integration of silica aerogels difficult.

[0004] Some applications require aerogel composites or aerogel blankets of varying thicknesses. For example, electric vehicle (EV) batteries particularly require composites or blankets with a thickness of 2 mm or less. Aerogel blankets can be cut into thin layers, but the fiber carrier has limitations on the minimum thickness, as layers that are too thin may lose their contained aerogel if they are not adequately secured within the carrier's fiber structure. Alternatively, composites of aerogel powder can be formed by mixing it with fibers and compressing the mixture. The existing solution is to encapsulate the resulting composite or blanket to prevent dust release into the surrounding area of ​​the aerogel composite, a method that makes handling difficult or adversely affects the overall system function. This is especially problematic in transport applications, where typical vibrations during use can lead to dust formation and release. Regardless of encapsulation, aerogel material can also be displaced within the blanket or composite by vibration, resulting in material inhomogeneity within the composite and impairing its function. This is particularly problematic for cell spacer applications in EV batteries, as such functional impairment could jeopardize the safety of the EV in the event of thermal runaway.

[0005] For example, EP0850206B1 describes an aerogel composite material made from small-diameter (<0.5 mm) aerogel particles and different physical or reactive binder systems. The binder and aerogel are mixed and the mixture is compressed. The binder forms a continuous phase, which reduces thermal conductivity through thermal bridging. EP0854892B1 describes a wet-process aerogel sheet requiring drying.

[0006] EP0963358B1 discloses an aerogel composite material based on aerogel particles, which are compressed with a thermoplastic binder into a sandwich structure. The binder and aerogel are mixed and the mixture is compressed. The binder forms a continuous phase, which reduces thermal conductivity through thermal bridging. WO2016053399A2 discloses a thin aerogel blanket based on a typical aerogel manufacturing process, which relies on supercritical drying using a thin blanket, requiring supercritical drying of the aerogel inside the blanket.

[0007] US9097377B2 discloses a thin aerogel composite material based on a thin aerogel blanket encapsulated in a laminated foil layer to prevent dust release, requiring the manufacture of the aerogel blanket, cutting it into thinner blankets, and a lamination step.

[0008] Another drawback of existing aerogel materials (such as silica aerogel blankets) is the costly preparation process. Most aerogel materials require supercritical drying methods to maintain the pore structure required in the wet gel stage during the drying phase. Supercritical drying requires pressure vessels and uses drying media in a supercritical state, such as CO2 or ethanol, which necessitates high pressure and high temperature. Aerogel blankets undergo supercritical drying in autoclaves, which require sufficiently large inner diameters (typically greater than 0.5 meters or even greater than 1 meter) and lengths to accommodate the rolled-up aerogel blankets, resulting in high construction and operating costs. Furthermore, due to diffusion limitations, increasing the thickness of the aerogel blanket leads to a longer supercritical drying time, and with a typical thickness of 5-20 mm, its drying time increases exponentially compared to the drying time of small aerogel particles with a diameter of less than 3-4 mm. In the case of aerogel blankets, loading and unloading the autoclave is difficult and requires the use of a high-pressure resistant, quick-opening lid, while alcohol gel particles and aerogel particles can be simply pumped in slurry form or transported via a pneumatic system. Furthermore, the silica aerogel materials disclosed in the prior art are usually in powder form.

[0009] Therefore, there is a need for an aerogel material that combines the advantages of time-saving and labor-saving aerogel preparation with the ease of manufacturing of blankets or composite materials that do not release any dust during use.

[0010] According to the present invention, this objective has been achieved by a composite material comprising two or more layers, the composite material comprising

[0011] (a) A layer (LA) with a thickness of 0.1 to 4 mm, which mainly consists of aerogel particles with a diameter of 0.1 to 4 mm before any compression, and

[0012] (b) An adjacent adhesive layer (LB) with a thickness of 0.01 to 1 mm,

[0013] (c) Optionally adjacent to the adhesive layer (LB) and on its opposite side, a support layer or cover layer (LC) with a thickness of 0.01 to 3 mm.

[0014] (d) Optionally, on the other side of the granular layer (LA), a second adjacent adhesive layer (LB') and a support layer or cover layer (LC'),

[0015] The aerogel particle layer (LA) includes a layer portion (LA-1) with a thickness of 0.01 to 1 mm, wherein the layer portion (LA-1) comprises both an adhesive and aerogel particles, and optionally includes a portion of a support layer (LC) located adjacent to the adhesive layer (LB).

[0016] The aerogel particle layer (LA) further includes a layer portion (LA-2) with a thickness equal to or greater than 0.05 mm without adhesive.

[0017] Surprisingly, it has been found that by adjusting the formulation of the aerogel particles, the ductility or brittleness of the particles can be controlled, resulting in ductile aerogel particles that do not break under compression or vibration and do not release any dust. Furthermore, it has been found that by arranging a tightly packed layer of such ductile aerogel particles and preferably subjecting this aerogel particle layer to simple compression, the aerogel particles form an aerogel layer suitable for thermal insulation. By combining a facing layer and an adhesive layer on both sides of the aerogel particle layer, a dust-free layered aerogel composite material can be obtained that does not release any dust during use or upon vibration.

[0018] Thickness can be determined, for example, by measuring distances in a cross-section using an optical microscope or by using X-ray computed tomography. For measuring thicknesses less than 10 μm, scanning electron microscopy or miniature X-ray computed tomography is preferred. For measuring thicknesses greater than 10 μm, either optical microscopy or scanning electron microscopy can be used. The composite material is cut into small pieces to obtain cross-sections from which the thickness of each layer is measured. Separation of the layers may be necessary before measurement.

[0019] The measurement of the thickness of a thin coating on a surface using bevel cutting and an optical microscope is described, for example, in ASTM D 4138. The measurement of thickness using a thickness gauge is described in ASTM D 6988.

[0020] The layer (LA) has a thickness of 0.1 to 4 mm and primarily comprises aerogel particles with a diameter of 0.1 to 4 mm before any compression, and may also include other particles. According to the invention, the layer (LA) may comprise more than 35% by volume, for example more than 50% by volume or more than 60% by volume, of aerogel particles with a diameter of 0.1 to 4 mm before any compression. According to the invention, the layer (LA) may also comprise aerogel particles with different diameters or aerogel particles with different compositions.

[0021] The layer (LA) may also not contain other particles. It is also possible to intentionally leave gaps between the aerogel particles in the layer (LA), or to fill the gaps with fillers or other materials, but the layer (LA) preferably contains more than 35% by volume of aerogel particles.

[0022] The thickness of the layer (LA) can be determined by measuring its individual thickness, for example, by measuring the cross-section of the corresponding sample. According to the invention, the thickness can be determined by measuring multiple samples and using the obtained average value. To measure the thickness of the layer (LA), the distance between the upper and lower surfaces of the layer (LA) parallel to the layer (LC) needs to be measured. These corresponding surfaces are defined by two planes formed by the largest aerogel particles in the layer (LA), thus obtaining the upper and lower boundaries of the layer (LA). The surfaces of the upper and lower planes are not flat, but vary with the size of the aerogel particles on the surface of the composite material.

[0023] A layer (LA) is defined as the sum of two aerogel layers (LA-1) and a layer (LA-2), wherein layer (LA-1) contains aerogel and adhesive from the adhesive layer (LB), and layer (LA-2) is an aerogel layer (LA) that does not contain adhesive from the adhesive layer (LB).

[0024] The thicknesses of layers (LA-1) and (LA-2) can be determined by measuring their respective thicknesses, for example, by measuring the thickness of each layer using a cross-section of its respective specimen. According to the invention, the thickness can also be determined by measuring multiple specimens and taking the average. To measure the thicknesses of layers (LA-1) and (LA-2), the distance between the respective surfaces of the layers defined by the aerogel particles and the surfaces formed by the adhesive between the aerogel particles is measured. If the composite material comprises layers (LB) and (LB'), then the thickness of layer (LA-2) is the average distance between the surfaces formed by the adhesive layers (LB) and (LB') between the aerogel particles.

[0025] The adhesives used in this invention can be categorized into solid adhesives (e.g., thermoplastic adhesives) and liquid adhesives (e.g., thermosetting adhesives). In both cases, to form a bond, the adhesive is converted into an incompressible liquid (within the maximum compression range of this invention). In the case of thermoplastic adhesives, the solid polymer is converted into a polymer melt by raising the temperature. Since the final composite material is dry, the thickness of the adhesive should also be measured in its final form (i.e., the solid adhesive layer). This implies that the adhesive thickness is measured after cooling in the case of thermoplastic adhesives, or after drying or curing in the case of thermosetting plastic adhesives.

[0026] The thickness of the layer (LB) can be determined by measuring its own thickness, for example, by measuring the thickness of the layer using a cross-section of the corresponding specimen. According to the invention, the thickness can be determined by measuring several specimens and using the obtained average value. To measure the thickness of the layer (LB), the distance between the upper and lower surfaces of the layer (LB) parallel to the layer (LC) is measured. These corresponding surfaces are defined by two planes formed by points above and below a given point in the composite material, from which the boundary of the layer (LB) can be obtained. These planes vary depending on the thickness of the layer (LB) on the surface of the composite material. Gaps may also exist in the layer (LB), for example, if it contains fibers coated with an adhesive.

[0027] For incompressible support layers (LC), the coating thickness of the adhesive layer (LB) can be determined using ISO 2808:2019, which describes methods for determining wet film thickness, dry film thickness, and film thickness of uncured powder layers.

[0028] The thickness of the support layer can be measured, for example, using a vernier caliper or a thickness gauge. Depending on the material of the layer (LC), various ASTM or ISO standards exist. According to the invention, the thickness can be determined by measuring several samples and using the obtained average value. If the support layer (LC) is coated with the layer (LB) at the measurement point, the thickness of the layer (LB) is subtracted from the measured thickness to obtain the actual thickness of the layer (LC). Alternatively, the layer (LB) and layer (LA) can be removed from the layer (LC) using methods known in the art before thickness measurement.

[0029] The support layer can be compressible (its thickness changes upon compression) or incompressible. To determine whether the support layer (LC) is compressible, the (LC) stack is compressed using a benchtop press up to 5 MPa for 5 minutes, and then the thickness is measured after the pressure is removed. If the average thickness of the support layer after compression differs from the average thickness of the (LC) stack before compression by less than 10 μm, the support layer is considered incompressible.

[0030] The layer (LC) may consist of fibers, nonwoven fabrics or similar materials.

[0031] The composite material of the present invention includes a layer (LA) and a layer (LB), and optionally layers (LC), (LB'), and (LC'). According to the present invention, the layer (LB) is adjacent to and generally adheres to the layer (LA). Specifically, the layer (LB) is at least partially adhered to the aerogel particles of the layer (LA), preferably more than 60% of the aerogel particles of the layer (LA) are adhered to.

[0032] According to another embodiment, the present invention also relates to a composite material as disclosed above, wherein an adhesive layer (LB) adheres more than 60% of the aerogel particles of the layer (LA) to a support layer (LC).

[0033] According to the present invention, the adhesive layer (LB) and the support layer (LC) can also be combined.

[0034] According to another embodiment, the present invention also relates to a composite material as disclosed above, wherein an adhesive layer (LB) and a support layer (LC) are combined or an adhesive layer (LB') and (LC') are combined.

[0035] Aerogel particles can be organic, such as those based on synthetic polymers like polyurethane, polyimide, etc., or inorganic, such as those based on silica, or mixtures of two or more polymers or systems. Suitable aerogel particles and their preparation methods are known in principle to those skilled in the art.

[0036] Aerogels can be hydrophobically treated or coated to achieve water and moisture resistance. Coatings can also impart functionality to aerogels. Adhesives can be incorporated into the coating. Examples of aerogel substrate coatings are illustrated in the following publication: https: / / doi.org / 10.1007 / s10570-021-04032-0.

[0037] To improve water and moisture resistance, the final composite material can be hydrophobically treated with hydrophobic agents known in the prior art (e.g., silanes such as TMCS, HMDSO or HMDZ), preferably in the gas phase.

[0038] The aerogel particle size is determined by the desired final composite thickness and surface layer thickness, the desired aerogel content in the layered composite, and the degree of compression. Smaller aerogel particles are prepared more quickly; however, very small aerogel particles, especially in the case of predominantly organic aerogels, may pose an explosion hazard or be difficult to handle during preparation and processing. Preferably, the aerogel particle size is less than 4 mm, less than 3 mm, less than 2 mm, less than 1 mm, and greater than 0.1 mm, preferably greater than 0.5 mm, and more preferably greater than 1 mm. Smaller aerogel particles can be prepared directly or by grinding or crushing larger aerogel particles. A mixture of two or more particle sizes can be used to replace the air voids between spherical particles of a given size, with smaller particles filling the air voids directly or after the compression step. In this way, the aerogel particle layer can be substantially free of air voids while not containing aerogel powder with a particle size less than 0.1 mm that would cause dust release from the composite.

[0039] The density of aerogel particles depends on the desired aerogel properties and is typically determined by a specific formulation. Ductile aerogel particles can be obtained from organic polymers (including biopolymers) and mixtures of organic polymers (including biopolymers) with inorganic precursors, as reported in PCT / EP2023 / 955870. For green composites, bio-based polymers are chosen. For refractory and high-temperature resistant composites, high inorganic content is selected while avoiding brittleness and dust formation.

[0040] According to another embodiment, the present invention also relates to a composite material as disclosed above, wherein the uncompressed aerogel particles of the layer (LA) have one or more of the characteristics (α) to (γ).

[0041] (α) Porosity of 80-99.6%,

[0042] (β) 15-200 kg / m 3 The bulk density of the particles,

[0043] (γ) The thermal conductivity of the loosely packed granular bed measured at 10 °C is 16-30 mW / mK.

[0044] It has been found that the aerogel particles used can be used to prepare composite materials with beneficial properties. These aerogel particles can be compressed, and stable composite materials can be obtained. Therefore, according to another embodiment, the present invention also relates to the composite material disclosed above, wherein a single aerogel particle can be compressed to 5% to 98% of its original thickness during compression at a compression rate of 0.01 to 5 mm / s without visible breakage of the aerogel particles, or with a force drop of less than 1 N due to initial breakage during compression.

[0045] Stable composite materials can be obtained from aerogel particles. It has been found that particularly stable composite materials can be obtained when using uncompressed aerogel particles with a diameter of 0.1 to 4 mm. Preferably, the particle size distribution of the aerogel is monodisperse, polydisperse, or partially monodisperse, and preferably, the sphericity of individual aerogel particles is 25% to 100%.

[0046] According to another embodiment, the present invention also relates to the composite material disclosed above, wherein:

[0047] (I) The particle size distribution of the aerogel is monodisperse, polydisperse, or partially monodisperse, and / or

[0048] (II) The sphericity of individual aerogel particles is 25% to 100%.

[0049] According to the present invention, silica-based aerogels have been found to have good properties for preparing composite materials. Preferably, the aerogel is a silica-based aerogel.

[0050] In particular, the hybrid aerogel contains a biopolymer selected from ionically crosslinkable polycarboxylate polymers, alginate, pectin, or modified cellulose.

[0051] The polarity of aerogels can also be adjusted through further processing steps on the aerogel itself. Suitable processing methods, such as hydrophobication, are known in principle.

[0052] According to another embodiment, the present invention also relates to the composite material disclosed above, wherein the aerogel is a silica-based aerogel, comprising...

[0053] (A) 20-80% by mass of silica and 20% of ionically crosslinkable polycarboxylate polymer, but at least 25 kg / m³ 3 Ion-crosslinkable polycarboxylate polymers, or

[0054] (B) 20-90% by mass silica and 10% by mass alginate, but at least 15 kg / m³ 3 alginate, or

[0055] (C) 20-85% by mass silica and 15% by mass pectin, but at least 20 kg / m³ 3 pectin, or

[0056] (D) 20-80% by mass silica and 20% by mass CMC, but at least 25 kg / m³ 3 CMC, or

[0057] (E) 20-85% by mass silica and 7.5% by mass alginate, and at least 15 kg / m³ 3 alginate and at least 10 kg / m 3 Non-algate ionically crosslinkable polycarboxylate polymers.

[0058] Aerogel particles may also contain other materials that modify material properties, such as lignin, tannins, polysaccharides, proteins, synthetic polymers, fillers, opacifiers, or materials that provide high-temperature stability, fire resistance, or elasticity. According to another embodiment, the invention also relates to the composite materials disclosed above, wherein the aerogel particles comprise lignin, tannins, polysaccharides, proteins, synthetic polymers, fillers, opacifiers, or materials that provide high-temperature stability, fire resistance, or elasticity.

[0059] Adhesives may be required to bond aerogel particles to a surface layer or to bond aerogel particles to each other, provided there is an adhesive-free layer (LA-2) to avoid negatively impacting the thermal barrier properties of the composite. The adhesive should not penetrate the aerogel layer beyond the depth defined by layer (LA-1); however, at least layer (LA-2) needs to be free of adhesives that form thermal bridges. Reactive adhesives such as acrylates, polyurethanes, epoxy resins, and silicones, or thermoplastic adhesives such as PE, PP, PA, TPU, silicone, and others can be used. For green composites, bio-based adhesives may be selected. The adhesive can be in the form of a liquid formulation, powder, sheet, nonwoven fabric, fiber, or other suitable geometry. The adhesive formulation needs to be selected in a way that avoids penetration and damage to the pores of the aerogel particles and avoids loss of barrier properties, for example, by using aqueous adhesive formulations and waterproof aerogel particles or high-viscosity adhesive formulations. The adhesive needs to exhibit good adhesion to the aerogel particles and any surface layer to achieve the mechanical integrity of the layered composite and prevent unwanted detachment or release of aerogel particles from the composite. Simultaneously, the adhesive layer should be as thin as possible to avoid negatively impacting the thermal insulation performance of the composite material. The adhesive is selected based on the operating temperature of the application; for example, thermoplastic adhesives should have a sufficiently high melting point. However, the temperature should not be too high, lest it damage the aerogel particles or the surface layer. Such adhesives are known in the prior art.

[0060] According to another embodiment, the present invention also relates to the composite material disclosed above, wherein the adhesive herein is selected from reactive adhesives based on acrylates, polyurethanes, epoxy resins, silicones, or water glass or other inorganic adhesive systems, or from thermoplastic adhesives based on PE, PP, PA, TPU, PLA, or other bio-based polymers, silicones, or mixtures of any of the above adhesives.

[0061] For manufacturing layered aerogel particle composites, an adhesive and surface layer can be formed first, and then aerogel particles can be added for bonding, rather than mixing the aerogel particles with the adhesive or coating the aerogel particles with the adhesive.

[0062] In the context of this invention, the adhesive itself may also be used, or an adhesive composition comprising the adhesive and suitable additives (e.g., fillers, particularly fiber fillers or refractory fillers).

[0063] Surprisingly, it has been discovered that by adjusting the formulation of the aerogel particles, refractory ductile aerogel particles that do not release dust can be obtained. Dust-free refractory layered aerogel composites can be prepared from these refractory ductile aerogel particles.

[0064] Aerogel particle composites can be prepared from aerogel particles using discontinuous or continuous methods. In principle, a cost-effective and rapid roll-to-roll method can be used.

[0065] The surface layer can be a nonwoven fabric, textile, or sheet, and is generally known in the prior art. The surface layer may consist of or contain the following materials: textiles or nonwoven fabrics, glass fibers, ceramic fibers, mica, cellulose, hemp, paper or coated paper, and other bio-based materials, synthetic polymers, and biopolymers. For green composites, bio-based materials are typically chosen. To obtain a thin surface layer with a high relative aerogel content in the composite material or the thin surface layer of a flexible composite material, a thin surface layer, for example, with a thickness of less than 2 mm, preferably less than 1 mm, more preferably less than 0.5 mm, and especially less than 0.1 mm, is advantageous.

[0066] According to another embodiment, the present invention also relates to composite materials as disclosed above, wherein the composite material comprises an elastic nonwoven fabric or blanket, elastic particles, or an elastic framework surrounding an aerogel layer (LA) that provides elasticity to the composite material when mechanically compressed.

[0067] When based on a thermoplastic binder layer, applying heat can temporarily soften the layered aerogel particle composite material.

[0068] To manufacture aerogel particle composites, compression may be necessary to improve the bonding between the aerogel particle layers and the adhesive and surface layers, reduce air gaps between aerogel particles, or decrease the thickness of the composite material. Preferably, the aerogel particles are compressed by no more than 80%, more preferably 50%, to avoid excessive density increase that could adversely affect the thermal insulation performance.

[0069] It has been found that the thermal conductivity of the aerogel particle bed is within a similar range to that of the composite material, for example, the λ value varies by no more than 5 mW / m*K, preferably 2 mW / m*K. The λ value of this composite material depends on the λ value of the aerogel particles and the relative thickness of the aerogel particle layer relative to the binder layer and the surface layer, but is expected to be less than 30 mW / m*K, preferably less than 25 mW / m*K, and more preferably less than 23 mW / m*K.

[0070] Multilayer compressed aerogel particle layers can be stacked to form thicker aerogel composites. The aerogel particle layers can be joined together using adhesives known in the art, or by sewing together a textile surface layer, also known in the art. Multiple layers of aerogel particles can also be arranged on top of each other, and the arranged multilayer aerogel particles can be compressed into a thicker aerogel composite. Adhesives may be needed to bond the particles in such a multilayer aerogel particle arrangement to each other, or to bond the aerogel particles to a surface layer. Multilayer arrangements of different types of aerogel particles can also be formed, or mixed layers can be prepared such as organic / organic, synthetic polymer / biopolymer, organic / inorganic, inorganic / inorganic, or in a specific order to obtain the desired properties of the aerogel composite.

[0071] Therefore, other types of layers or surface layers can be introduced to give aerogel particle composites additional functions, such as electrical insulation layers, thermally conductive layers, phase change materials, mechanical shock resistant layers, waterproof layers, or fireproof layers.

[0072] Elastic layers can be introduced to impart elastic behavior to composite materials. This is particularly advantageous for compensating for the expansion and contraction of battery cells in electric vehicles during operation and battery life. For example, one or more adhesive layers can be elastic, for instance, by using thermoplastic elastomers or elastomer sheets, meshes, powders, molded geometries, granules, and the like, such as TPU. Elastic particles or molded geometries (e.g., elastomer beads, 3D-printed parts, or molded parts) can also be introduced into the aerogel particle layer (LA). Furthermore, smaller elastic particles can be integrated into the aerogel particle layer (LA) during the gelation step of the manufacturing process to enhance and modulate its elasticity. The elastic behavior of aerogel particles can also be modified by varying the content and type of biopolymer.

[0073] Typically, the thickness of the composite material of the present invention is 0.1 to 20 mm, for example 0.2 to 15 mm, preferably 0.3 to 10 mm or 0.5 to 5 mm.

[0074] Typically, the layers (LA) and (LB) comprise at least 20% of the composite material, preferably at least 30%, and especially at least 50%. If the composite material comprises multiple layers (LA) and / or layers (LB), the sum of the layers (LA) and layers (LB) typically comprises at least 20% of the composite material, preferably at least 30%, and especially at least 50%.

[0075] Suitable methods for preparing aerogel powders or aerogel beads are known in principle to those skilled in the art.

[0076] Suitable methods may include, for example, gel preparation, solvent exchange, and drying steps.

[0077] According to another embodiment, the present invention also relates to a method for preparing a composite material as disclosed above, wherein aerogel beads are obtained by solvent exchange and supercritical drying or freeze-drying.

[0078] The preparation of aerogel particles avoids the time-consuming and labor-intensive supercritical drying process of silica aerogel blankets. Supercritical drying of aerogel particles is known in principle and can be carried out in a small-diameter tube, which can serve as an autoclave for aerogel particles, without the need for a large and expensive autoclave like that used for silica aerogel blankets.

[0079] Suitable methods for preparing aerogel particle gel precursors are known in principle to those skilled in the art. Suitable methods may include ionic crosslinking or pH-induced crosslinking.

[0080] According to another embodiment, the present invention also relates to the composite material disclosed above, wherein the aerogel particles are prepared by ionic crosslinking or pH-induced crosslinking.

[0081] Typically, a gel is formed from the components of a mixture (M1) and at least one polyvalent metal ion. The mixture (M1) contains components suitable for forming a gel with the polyvalent metal ion, and in particular, must have suitable functional groups.

[0082] Typically, a mixture (M1) is contacted with an aqueous solution of polyvalent metal ions to prepare a gel (A). Suitable mixing steps are known in principle to those skilled in the art. For example, the mixture (M1) can be added dropwise to an aqueous solution of polyvalent metal ions to prepare spherical aerogel particles. The mixture (M1) can also be provided in the pores of a carrier material or as a mixture with fibers, and then contacted with an aqueous solution of polyvalent metal ions to prepare a gel (A). The mixture (M1) can also be contacted with polyvalent metal ions in an emulsion or in a spray process.

[0083] Gelation itself is well known to those skilled in the art and is described, for example, on page 21, line 19 to page 23, line 13 of WO 2009 / 027310.

[0084] Preferably, the conditions are adjusted, and the hydrogel, alcohol gel, and / or aerogel are spherical. Preferably, according to step b), spherical beads with an average diameter of 0.1 to 4 mm, preferably 1 to 2 mm, are obtained.

[0085] Preferably, no cross-linking or hydrophobication occurs through covalent chemical reactions.

[0086] Preferably, the temperature and pressure in the gelation step are adjusted to conditions suitable for gel formation. A suitable temperature can be 5 to 40°C, preferably 15 to 35°C. According to another embodiment, the invention also relates to the method disclosed above, wherein step b) is performed at a temperature of 5 to 40°C.

[0087] The formation rate of insoluble gels can be controlled very precisely and easily by selecting appropriate conditions.

[0088] Gel (A) is typically a water-containing gel, i.e., a hydrogel. Gel (A) is usually exposed to a water-miscible solvent (L) to obtain gel (B), i.e., an organic gel.

[0089] In the context of this invention, "water miscibility" means that the solvent is at least partially miscible with water so that solvent exchange can occur in the gel.

[0090] Solvent exchange can be performed either by directly immersing the gel in a new solvent (one-step method) or by immersing it in a mixture of different water and a new solvent (gradually increasing the amount of new solvent) after a certain period of time in the previous immersion step (exchange frequency) (multi-step method) (Robitzer et al., 2008, Langmuir, 24(21), 12547-12552). The solvent selected for replacing water must meet the following requirements: it must not dissolve the gel structure, be completely soluble in its previous solvent (water), and preferably be acceptable for pharmaceutical preparation. Furthermore, if the method includes a supercritical drying step, the solvent (L) is preferably at least partially miscible with the supercritical medium.

[0091] The solvent (L) can in principle be any suitable compound or a mixture of compounds that meets the above requirements, and the solvent (L) is a liquid under the temperature and pressure conditions used in the method.

[0092] Possible solvents (L) include, for example, alcohols, ketones, aldehydes, alkyl esters of alkanes, organic carbonates, amides (such as formamide and N-methylpyrrolidone), sulfoxides (such as dimethyl sulfoxide), aliphatic and cycloaliphatic halogenated or non-halogenated hydrocarbons, halogenated or non-halogenated aromatic compounds, and fluorinated ethers. Mixtures of two or more of the above compounds are also possible.

[0093] In many cases, a particularly suitable solvent (L) is obtained by using a compound selected from two or more of the solvents mentioned above that is completely miscible.

[0094] Suitable solvents, especially alcohols and ketones, such as C1 to C6 alcohols and C1 to C6 ketones and mixtures thereof.

[0095] It is particularly suitable for alcohols such as methanol, ethanol and isopropanol, and ketones such as acetone and methyl ethyl ketone.

[0096] Solvent exchange can be performed using solvents of varying concentrations in a one-step, two-step, three-step, or multi-step manner. According to a preferred embodiment, the gel (A) is sequentially immersed in ethanol / water mixtures at concentrations of, for example, 30, 60, 90, and 100 wt%, for 5 minutes to 12 hours in each solvent, depending on the particle size and porosity. Solvent exchange can also be performed continuously.

[0097] Gel (B) was obtained by solvent exchange and then dried.

[0098] Drying is typically carried out using known methods. Drying is preferably carried out under supercritical conditions, preferably after replacing the solvent with CO2 or another solvent suitable for supercritical drying. This drying method is known to those skilled in the art. Supercritical conditions describe a temperature or pressure at which the CO2 or any solvent used to remove the gelling solvent exists in a supercritical state. This reduces the shrinkage of the gel during solvent removal.

[0099] Alternatively, the obtained gel can be dried by converting the liquid contained in the gel into a gaseous state at a temperature and pressure lower than the critical temperature and critical pressure of the liquid contained in the gel.

[0100] Preferably, the obtained gel is dried by converting the solvent (L) into a gaseous state at a temperature and pressure below the critical temperature and critical pressure of the solvent (L). Therefore, drying is preferably carried out by removing the solvent (L) present in the reaction, without prior substitution with another solvent.

[0101] These methods are also known to those skilled in the art and are described in WO 2009 / 027310, page 26, line 22 to page 28, line 36.

[0102] Drying can be achieved by converting the liquid contained in the gel into a gaseous state at temperatures and pressures below the critical temperature and critical pressure of the liquid contained in the gel. The drying process can also be carried out under supercritical conditions.

[0103] The method may also include one or more other modification steps, such as a molding step (which may include fibers and / or adhesives and / or thermoplastic materials), a compression step, a lamination step, a hydrophobication step, or a carbonization step. For example, one or more of these steps may be combined, such as a post-drying step and a hydrophobication step.

[0104] According to the present invention, in particular, hybrid aerogels have been found to have good properties for preparing the composite materials of the present invention. In particular, suitable hybrid aerogels comprise secondary materials and biopolymers selected from ionically crosslinkable polycarboxylate polymers, alginates, pectin, or modified cellulose.

[0105] Suitable methods for preparing biopolymer-based aerogels are known in principle to those skilled in the art. Typically, aerogels are obtained by methods involving gel formation, solvent exchange, and drying. According to another embodiment, the invention also relates to the liquid or paste-like compositions disclosed above, wherein the aerogel beads are obtained by solvent exchange and supercritical drying or freeze-drying.

[0106] For example, a suitable aerogel can be prepared by a method comprising at least the following steps:

[0107] a) Provide a mixture (M1) comprising at least one compound selected from water-soluble biopolymers and inorganic precursors (C1), and at least one water-soluble polysaccharide with a carboxylic acid group as a component (C2), and water.

[0108] b) The mixture (M1) is contacted with an aqueous solution of polyvalent metal ions to prepare a gel (A).

[0109] c) Expose the gel (A) obtained in step b) to a water-miscible solvent (L) to obtain gel (B).

[0110] d) Dry the gel (B) obtained in step c.

[0111] In the context of this invention, a suitable inorganic precursor must be soluble or at least partially soluble in the mixture (M1) and must be solidified in the gelation step.

[0112] For the purposes of this invention, the gel is a polymer-based crosslinking system, wherein the polymer is in contact with a liquid (referred to as a solvated gel or lyophilized gel) or with water as a liquid (referred to as a hydrogel or aqueous gel). The polymer phase forms a continuous three-dimensional network.

[0113] In the context of this invention, "water-soluble" means having sufficient solubility in water to form a solution suitable for preparing a gel. In the context of this invention, aqueous swelling dispersions can also be used to prepare gels.

[0114] The properties of aerogels can be customized by adjusting the composition of the mixture (M1), the hydrogel (A) formation stage or solvent exchange step, and the reaction conditions in the drying step. According to the present invention, the properties of hydrogels and / or aerogels can be influenced by changing the component ratios, the control parameters of step b), and by introducing various organic and inorganic materials into the gel matrix.

[0115] According to another aspect, the present invention also relates to a method for preparing a composite material comprising two or more layers, the method comprising the following steps:

[0116] (i) Forming an adhesive layer (LB),

[0117] (ii) Formation of a layer primarily consisting of aerogel particles (LA),

[0118] (iii) By applying appropriate conditions to achieve a stable bond between layers (LA) and (LB), a composite material comprising layers (LA) and (LB) is formed.

[0119] The uncompressed laminar (LA) aerogel particles preferably have one or more of the characteristics (α) to (γ).

[0120] (α) Porosity 80-99.6%

[0121] (β) 15-200kg / m 3 Particle bulk density

[0122] (γ) The thermal conductivity of the loosely packed particle bed, measured at 10°C, is 16-30 mW / mK.

[0123] In particular, the present invention relates to a method for preparing a composite material comprising two or more layers, the method comprising the following steps:

[0124] (i) Forming an adhesive layer (LB),

[0125] (ii) Forming a layer (LA) containing aerogel particles with a diameter of 0.1 to 4 mm prior to any compression.

[0126] (iii) By applying appropriate conditions to achieve a stable bond between layers (LA) and (LB) and to form a layer portion (LA-1) containing adhesive and aerogel particles with a thickness of 0.01 to 1 mm and a layer portion (LA-2) without adhesive with a thickness equal to or greater than 0.05 mm, a composite material comprising layers (LA) and (LB) is formed.

[0127] The uncompressed aerogel particles of the layer (LA) preferably have one or more of the characteristics (α) to (γ).

[0128] (α) Porosity of 80-99.6%;

[0129] (β) 15-200kg / m 3 The bulk density of the particles;

[0130] (γ) The thermal conductivity of the loosely packed particle bed, measured at 10°C, is 16-30 mW / mK.

[0131] The method of the present invention includes steps (i), (ii) and (iii), but may also include other steps.

[0132] Regarding the preferred aerogel particles used, please refer to the above disclosure.

[0133] According to another embodiment, the present invention also relates to the method disclosed above, wherein the aerogel is a silica-based aerogel.

[0134] According to another embodiment, the present invention also relates to the method disclosed above, wherein the aerogel is a silica-based aerogel, comprising...

[0135] (A) 20-80% by mass of silica and 20% of ionically crosslinkable polycarboxylate polymer, but at least 25 kg / m³ 3 Ion-crosslinkable polycarboxylate polymers, or

[0136] (B) 20-90% by mass silica and 10% by mass alginate, but at least 15 kg / m³ 3 alginate, or

[0137] (C) 20-85% by mass silica and 15% by mass pectin, but at least 20 kg / m³ 3 pectin, or

[0138] (D) 20-80% by mass silica and 20% by mass CMC, but at least 25 kg / m³ 3 CMC, or

[0139] (E) 20-85% by mass silica and 7.5% by mass alginate, and at least 15 kg / m³ 3 alginate and at least 10 kg / m 3 Non-algate ionically crosslinkable polycarboxylate polymers.

[0140] It has been found that particularly stable composite materials can be obtained by applying pressure to the composite material. According to another embodiment, the invention also relates to the method disclosed above, wherein the method includes the following steps:

[0141] (iv) Compression of the composite material, compressing the aerogel to 5-98% of its original thickness.

[0142] (v) A compression rate of 0.01-1 mm / sec is preferred.

[0143] The composite material may also include other layers, such as coatings or other layers containing aerogel particles. According to another embodiment, the invention also relates to the method disclosed above, wherein other layers containing aerogel particles are formed as part of the composite material.

[0144] Furthermore, for preferred embodiments of the composite material, please refer to the disclosure above. According to another embodiment, the invention also relates to the method disclosed above, wherein the thickness of the composite material is 0.1 to 20 mm.

[0145] According to another embodiment, the present invention also relates to the method disclosed above, wherein the thickness of the layer (LA) containing aerogel particles is 0.1 to 4 mm.

[0146] According to another embodiment, the present invention also relates to the method disclosed above, wherein the diameter of the uncompressed aerogel particles is 0.1 to 4 mm.

[0147] According to another embodiment, the present invention also relates to the method disclosed above, wherein the adhesive is selected from acrylates, polyurethanes, epoxy resins, silicones, or thermoplastic adhesives, such as PE, PP, PA, TPU, PLA.

[0148] According to another aspect, the present invention also relates to composite materials obtained according to the methods disclosed above.

[0149] It has been found that the composite material has good stability and good barrier properties, making it suitable for use as insulation material in buildings and structures, appliances, temperature-controlled logistics, cryogenic applications, oil and gas applications or clothing, or as a heat shield material in batteries or a material to prevent heat transfer.

[0150] According to another aspect, the present invention also relates to the above-mentioned composite material as a thermal insulation material for buildings and structures, appliances, temperature-controlled logistics, cryogenic applications, automotive applications, infrastructure applications, marine applications, oil and gas applications or clothing, or as a thermal insulation material in batteries or a material that prevents heat transmission.

[0151] Preferred embodiments can be found in the claims and description. Combinations of preferred embodiments do not depart from the scope of the invention. Preferred embodiments of the components used are described below.

[0152] The present invention includes the following embodiments, wherein these embodiments include specific combinations of embodiments as defined therein by the various cross-reference relationships.

[0153] The present invention is further illustrated by the following series of embodiments and combinations thereof, which derive from the indicated references and backreferences. It is particularly important to note that in each instance referring to the scope of an embodiment, such as in the context of the term "composite material of any one of embodiments 1 to 4," each embodiment within that scope is intended to explicitly disclose to those skilled in the art that the term should be understood to be synonymous with "composite material of any one of embodiments 1, 2, 3, and 4." Furthermore, it should be explicitly stated that the following series of embodiments represents suitable structural portions of a general description of preferred aspects of the invention, and therefore, they adequately support the claims of the invention, but do not represent the claims of the invention.

[0154] 1. A composite material comprising two or more layers, comprising:

[0155] (a) A layer (LA) with a thickness of 0.1 to 4 mm, comprising aerogel particles with a diameter of 0.1 to 4 mm prior to any compression, and

[0156] (b) An adjacent adhesive layer (LB) with a thickness of 0.01 to 1 mm,

[0157] (c) Optionally adjacent to the adhesive layer a support layer (LC) with a thickness of 0.01 to 3 mm.

[0158] (d) Optionally, on the other side of the granular layer (LA), a second adjacent adhesive layer (LB') and a support layer or cover layer (LC'),

[0159] The aerogel particle layer (LA) includes a layer portion (LA-1) with a thickness of 0.01 to 1 mm, the layer portion (LA-1) comprising both the adhesive and the aerogel particles, and optionally a partial support layer (LC), located adjacent to the adhesive layer (LB).

[0160] The aerogel particle layer (LA) further includes a layer portion (LA-2) with a thickness equal to or greater than 0.05 mm without adhesive.

[0161] 2. The composite material according to embodiment 1, wherein the adhesive layer (LB) adheres more than 60% of the aerogel particles of the layer (LA) to the support layer (LC).

[0162] 3. The composite material according to embodiment 1 or 2, wherein the adhesive layer (LB) and the support layer (LC) or the adhesive layer (LB') and (LC') are bonded together.

[0163] 4. The composite material according to any one of embodiments 1 to 3, wherein the uncompressed aerogel particles of the layer (LA) have one or more of the characteristics (α) to (γ).

[0164] (α) Porosity of 80-99.6%,

[0165] (β) Particle bulk density of 15-200 kg / m³

[0166] (γ) The thermal conductivity of the loosely packed granular bed, measured at 10°C, is 16-30 mW / mK.

[0167] 5. The composite material according to any one of embodiments 1 to 4, wherein

[0168] Individual aerogel particles can be compressed to 5-98% of their original thickness during compression at rates ranging from 0.01 to 5 mm / sec without visible breakage of the aerogel particles, or

[0169] The force drop during compression due to initial fracture is less than 1 N.

[0170] 6. The composite material according to any one of embodiments 1 to 5, wherein,

[0171] (I) The aerogel particle size distribution is monodisperse, polydisperse, or partially monodisperse, and / or

[0172] (II) The sphericity of individual aerogel particles is 25% to 100%.

[0173] 7. The composite material according to any one of embodiments 1 to 6, wherein the aerogel is a silica-based aerogel, preferably wherein the aerogel is a silica-based aerogel, and the silica-based aerogel comprises...

[0174] (A) 20-80% by mass of silica and 20% of ionically crosslinkable polycarboxylate polymer, but at least 25 kg / m³ 3 Ion-crosslinkable polycarboxylate polymers, or

[0175] (B) 20-90% by mass silica and 10% by mass alginate, but at least 15 kg / m³ 3 alginate, or

[0176] (C) 20-85% by mass silica and 15% by mass pectin, but at least 20 kg / m³ 3 pectin, or

[0177] (D) 20-80% by mass silica and 20% by mass CMC, but at least 25 kg / m³ 3CMC, or

[0178] (E) 20-85% by mass silica and 7.5% by mass alginate, and at least 15 kg / m³ 3 alginate and at least 10 kg / m 3 Non-algate ionically crosslinkable polycarboxylate polymers.

[0179] 8. The composite material according to any one of embodiments 1 to 7, wherein the aerogel particles comprise lignin, tannic acid, polysaccharide, protein, synthetic polymer, filler, opacifier, or material providing high-temperature stability, fire resistance, or elasticity.

[0180] 9. The composite material according to any one of embodiments 1 to 8, wherein the aerogel particles are prepared by ionic crosslinking or pH-induced crosslinking.

[0181] 10. The composite material according to any one of embodiments 1 to 9, wherein the adhesive is selected from reactive adhesives based on acrylates, polyurethanes, epoxy resins, silicones, or water glass or other inorganic adhesive systems, or from thermoplastic adhesives based on PE, PP, PA, TPU, PLA, or other bio-based polymers, silicones, or any mixture of those adhesives.

[0182] 11. The composite material according to any one of embodiments 1 to 10, wherein the composite material comprises an elastic nonwoven fabric or blanket, elastic particles, an elastic molded body, or an elastic frame surrounding an aerogel layer (LA) that provides elasticity to the composite material when mechanically compressed.

[0183] 12. A method for preparing a composite material comprising two or more layers, comprising the following steps:

[0184] (i) Forming an adhesive layer (LB),

[0185] (ii) Forming a layer (LA) containing aerogel particles with a diameter of 0.1 to 4 mm prior to any compression.

[0186] (iii) By applying suitable conditions to achieve a stable bond between layers (LA) and (LB), a composite material comprising layers (LA) and (LB) is formed.

[0187] The uncompressed aerogel particles of layer (LA) have one or more of the following properties (α) to (γ).

[0188] (α) Porosity of 80-99.6%;

[0189] (β) 15-200kg / m 3 The bulk density of the particles;

[0190] (γ) The thermal conductivity of the loosely packed particle bed, measured at 10°C, is 16-30 mW / mK.

[0191] 13. A method for preparing a composite material comprising two or more layers, comprising the following steps:

[0192] (i) Forming an adhesive layer (LB),

[0193] (ii) Forming a layer (LA) containing aerogel particles with a diameter of 0.1 to 4 mm prior to any compression.

[0194] (iii) By applying suitable conditions to achieve a stable bond between layers (LA) and (LB) and to form a layer portion (LA-1) containing both adhesive and aerogel particles with a thickness of 0.01 to 1 mm and a layer portion (LA-2) without adhesive with a thickness equal to or greater than 0.05 mm, a composite material comprising layers (LA) and (LB) is formed.

[0195] The uncompressed aerogel particles of layer (LA) preferably have one or more of the characteristics (α) to (γ).

[0196] (α) Porosity of 80-99.6%;

[0197] (β) 15-200kg / m 3 The bulk density of the particles;

[0198] (γ) The thermal conductivity of the loosely packed particle bed, measured at 10°C, is 16-30 mW / mK.

[0199] 14. The method according to embodiment 12 or 13, wherein the aerogel is a silica-based aerogel.

[0200] 15. The method according to any one of embodiments 12 to 14, wherein the aerogel is a silica-based aerogel, comprising...

[0201] (A) 20-80% by mass of silica and 20% of ionically crosslinkable polycarboxylate polymer, but at least 25 kg / m³ 3 Ion-crosslinkable polycarboxylate polymers, or

[0202] (B) 20-90% by mass silica and 10% by mass alginate, but at least 15 kg / m³ 3 alginate, or

[0203] (C) 20-85% by mass silica and 15% by mass pectin, but at least 20 kg / m³ 3 pectin, or

[0204] (D) 20-80% by mass silica and 20% by mass CMC, but at least 25 kg / m³ 3 CMC, or

[0205] (E) 20-85% by mass silica and 7.5% by mass alginate, and at least 15 kg / m³ 3 alginate and at least 10 kg / m 3 Non-algate ionically crosslinkable polycarboxylate polymers.

[0206] 16. The method according to any one of embodiments 12 to 15, wherein the method comprises the following steps:

[0207] (iv) Compression composites compress the aerogel to 5-98% of its original thickness.

[0208] 17. The method according to any one of embodiments 12 to 16, wherein the method comprises the following steps:

[0209] (iv) Compression composites compress the aerogel to 5-98% of its original thickness.

[0210] (v) Apply a compression rate of 0.01-1 mm / sec.

[0211] 18. The method according to any one of embodiments 12 to 17, wherein additional layers comprising aerogel particles are formed as part of the composite material.

[0212] 19. The method according to any one of embodiments 12 to 18, wherein the thickness of the composite material is 0.1 to 20 mm.

[0213] 20. The method according to any one of embodiments 12 to 19, wherein the thickness of the layer (LA) containing aerogel particles is 0.1 to 4 mm.

[0214] 21. The method according to any one of embodiments 12 to 20, wherein the adhesive is selected from acrylates, polyurethanes, epoxy resins, silicones or thermoplastic adhesives, such as PE, PP, PA, TPU, PLA.

[0215] 22. The method according to any one of embodiments 12 to 21, wherein the thickness of the adhesive layer (LB) is 0.01 to 1 mm.

[0216] 23. The method according to any one of embodiments 12 to 22, wherein the composite material includes a support layer (LC) adjacent to the adhesive layer, having a thickness of 0.01 to 3 mm.

[0217] 24. The method according to any one of embodiments 12 to 23, wherein the aerogel particle layer (LA) comprises a layer portion (LA-1) with a thickness of 0.01 to 1 mm, said layer portion (LA-1) comprising both an adhesive and aerogel particles, and optionally comprising a partial support layer (LC), and located adjacent to the adhesive layer (LB), and

[0218] The aerogel particle layer (LA) also includes a non-adhesive layer portion (LA-2) with a thickness equal to or greater than 0.05 mm.

[0219] 25. The method according to any one of embodiments 12 to 24, wherein the adhesive layer (LB) adheres more than 60% of the aerogel particles of the layer (LA) to the support layer (LC).

[0220] 26. The method according to any one of embodiments 12 to 25, wherein the adhesive layer (LB) and the support layer (LC) or the adhesive layer (LB') and (LC') are bonded together.

[0221] 27. The method according to any one of embodiments 12 to 26, wherein the uncompressed aerogel particles of the layer (LA) have one or more of the characteristics (α) to (γ).

[0222] (α) Porosity of 80-99.6%,

[0223] (β) 15-200kg / m 3 The bulk density of the particles,

[0224] (γ) The thermal conductivity of the loosely packed particle bed, measured at 10°C, is 16-30 mW / mK.

[0225] 28. The method according to any one of embodiments 12 to 27, wherein

[0226] Individual aerogel particles can be compressed to 5-98% of their original thickness during compression at rates ranging from 0.01 to 5 mm / sec, without visible breakage of the aerogel particles, or

[0227] The force drop during compression due to initial fracture is less than 1 N.

[0228] 29. The method according to any one of embodiments 12 to 28, wherein,

[0229] (I) The aerogel particle size distribution is monodisperse, polydisperse, or partially monodisperse, and / or

[0230] (II) The sphericity of individual aerogel particles ranges from 25% to 100%.

[0231] 30. The method according to any one of embodiments 12 to 29, wherein the aerogel particles contain lignin, tannic acid, polysaccharide, protein, synthetic polymer, filler, opacifier or material providing high temperature stability or fire resistance or elasticity.

[0232] 31. The method according to any one of embodiments 12 to 30, wherein the aerogel particles are prepared by ionic crosslinking or pH-induced crosslinking.

[0233] 32. The method according to any one of embodiments 12 to 31, wherein the adhesive is selected from reactive adhesives based on acrylates, polyurethanes, epoxy resins, silicones, or water glass or other inorganic adhesive systems, or from thermoplastic adhesives based on PE, PP, PA, TPU, PLA, or other bio-based polymers, silicones, or mixtures of any of these adhesives.

[0234] 33. The method according to any one of embodiments 12 to 32, wherein the composite material comprises an elastic nonwoven fabric or blanket, elastic particles, an elastic molded body, or an elastic frame surrounding an aerogel layer (LA) that provides elasticity when mechanically compressed.

[0235] 34. The composite material obtained by the method according to any one of embodiments 12 to 33.

[0236] 35. The composite material described in any one of embodiments 1 to 11 or embodiment 34, or the composite material obtained or obtainable by any one of embodiments 12 to 33, is used as a thermal insulation material for buildings and structures, appliances, temperature-controlled logistics, cryogenic applications, automotive applications, infrastructure applications, marine applications, oil and gas applications, or clothing, or as a thermal insulation material in batteries or a material that prevents heat transfer. Attached Figure Description

[0237] Figure 1 A possible schematic structure of a cross-section of a composite material with different layer structures is shown.

[0238] Figure 1 (a) shows a schematic cross-sectional view of a composite material having layers (LA), (LB), and (LC). The total thickness (LT) of the composite material conforms to the following formula:

[0239]

[0240] Figure 1 (b) shows a schematic cross-sectional view of a composite material having layers (LA), (LB), (LC), (LB'), and (LC'). The total thickness (LT) of the composite material conforms to the following formula:

[0241]

[0242] Figure 1 (c) shows a schematic cross-sectional view of a composite material having layers (LA), (LB) and (LC), wherein portions 1, 2, and 3 have different thicknesses, and layers (LA) and (LA-2) have average thicknesses.

[0243] Figure 2 A schematic cross-sectional view of a composite material having layers (LA), (LB), and (LC) is shown, wherein the layers (LB) or (LB) and (LC) have varying thicknesses.

[0244] Figure 3 A schematic cross-sectional view of a composite material having layers (LA), (LB), and (LC) is shown. Layer LC is a fiber layer, and the adhesive covering the fibers results in the average thickness of layers (LA), (LB), and (LC).

[0245] The present invention will be illustrated below using examples. Example

[0246] 1. Preparation of aerogels

[0247] Aerogel particles were prepared as follows: Colloidal silica (CS, Levasil CS15-340P, from Nouryon) and sodium alginate (SA, Protanal LF120, from IFF) were mixed with water to obtain a precursor solution of a given target concentration. 1 liter of the precursor solution was added dropwise to a 5 liter calcium chloride (20 g / L) treatment tank at room temperature to form hydrogel particles. The particle size of the hydrogel particles was controlled to be between 0.1 mm and 4 mm in diameter by the dropwise addition method. The water in the hydrogel particles was exchanged to approximately 98% ethanol through a ten-step process by thorough contact with 98% ethanol, achieved by immersion in 98% ethanol at room temperature for approximately 3 hours in ten times the volume of the particles. The resulting alcohol-gel particles were dried with supercritical CO2 to obtain aerogel particles. If necessary, the aerogel particles were ground into powder (particle size 10-100 µm) by stirring in a kitchen blender for approximately 60 seconds.

[0248] 2. Preparation of composite materials

[0249] 2.1 Materials

[0250] Aerogel particles as disclosed above. Glass fiber surface layer (approximately 0.2 mm thick). Hot melt mesh (copolyester, 100 x 100 g / m²). 2 ).

[0251] 2.2 Single-layer composite materials

[0252] Aerogel particles are laid on a first glass fiber surface layer (20×20 cm) and a first hot-melt mesh layer (20×20 cm), and then covered with a second hot-melt mesh layer and a glass fiber surface layer. The assembly is compressed to the target thickness for approximately 30 seconds at a temperature higher than the melting temperature of the hot-melt mesh, resulting in a layered composite sheet in which the sides of the aerogel particles are bonded together by the hot-melt mesh located between the two glass fiber surface layers. The hot-melt mesh does not penetrate into the central portion of the composite material, forming a layer of aerogel particles without adhesive.

[0253] 2.3 Multilayer composite materials

[0254] Aerogel particles are laid on a glass fiber surface layer with a layer of hot-melt mesh, and then covered with another layer of hot-melt mesh. This alternating layering of ductile aerogel particles and hot-melt mesh is repeated. The assembly is then covered with a final glass fiber surface layer and compressed to the target thickness for approximately 30 seconds at a temperature higher than the melting point of the hot-melt mesh, resulting in a thick layered aerogel particle composite material. The total thickness of this thick layered aerogel composite material is controlled by the number of layers.

[0255] 3. Composite material testing

[0256]

[0257] CS: Colloidal silica, SA: Sodium alginate, TC: Thermal conductivity (measured using a Fox 200).

[0258] *-: Composite materials are easy to pull apart; +: Composite materials are not easy to pull apart.

[0259] **: -: Burning; +: Not burning, may be charred.

[0260] References cited:

[0261] EP 0850206 B1

[0262] EP 0854892 B1

[0263] EP 0963358 B1

[0264] WO 2016 / 053399 A2

[0265] US 9097377 B2

[0266] PCT / EP2023 / 955870

[0267] Robitzer et al., 2008, Langmuir, 24(21), 12547-12552

[0268] WO 2009 / 027310

Claims

1. A composite material comprising two or more layers, comprising: (a) A layer (LA) with a thickness of 0.1 to 4 mm, said layer (LA) comprising aerogel particles with a diameter of 0.1 to 4 mm before any compression, and (b) An adjacent adhesive layer (LB) with a thickness of 0.01 to 1 mm. (c) Optionally adjacent to the adhesive layer a support layer (LC) with a thickness of 0.01 to 3 mm. (d) Optionally, on the other side of the granular layer (LA), a second adjacent adhesive layer (LB') and a support layer or cover layer (LC'), The aerogel particle layer (LA) includes a layer portion (LA-1) with a thickness of 0.01 to 1 mm, comprising both the adhesive and aerogel particles, and located adjacent to the adhesive layer (LB). The aerogel particle layer (LA) further includes a layer portion (LA-2) with a thickness equal to or greater than 0.05 mm without adhesive.

2. The composite material according to claim 1, wherein the adhesive layer (LB) adheres more than 60% of the aerogel particles of the layer (LA) to the support layer (LC).

3. The composite material according to claim 1 or 2, wherein the adhesive layer (LB) and the support layer (LC) or the adhesive layer (LB') and (LC') are bonded together.

4. The composite material according to any one of claims 1 to 3, wherein the uncompressed aerogel particles of the layer (LA) have one or more of the characteristics (α) to (γ). (α) Porosity of 80-99.6%, (β) Particle bulk density of 15-200 kg / m³ (γ) The thermal conductivity of the loosely packed granular bed measured at 10 °C is 16-30 mW / mK.

5. The composite material according to any one of claims 1 to 4, wherein Individual aerogel particles can be compressed to 5-98% of their original thickness during compression at compression rates of 0.01 to 5 mm / sec without visible breakage of the aerogel particles, or with a force drop of less than 1 N due to initial breakage during compression.

6. The composite material according to any one of claims 1 to 5, wherein, (I) The aerogel particle size distribution is monodisperse, polydisperse, or partially monodisperse, and / or (II) The sphericity of individual aerogel particles is 25% to 100%.

7. The composite material according to any one of claims 1 to 6, wherein the aerogel is a silica-based aerogel, comprising... (A) 20-80% by mass of silica and 20% of ionically crosslinkable polycarboxylate polymer, but at least 25 kg / m³ 3 Ion-crosslinkable polycarboxylate polymers, or (B) 20-90% by mass silica and 10% by mass alginate, but at least 15 kg / m³ 3 alginate, or (C) 20-85% by mass silica and 15% by mass pectin, but at least 20 kg / m³ 3 pectin, or (D) 20-80% by mass silica and 20% by mass CMC, but at least 25 kg / m³ 3 CMC, or (E) 20-85% by mass silica and 7.5% by mass alginate, with a content of at least 15 kg / m³. 3 alginate and at least 10 kg / m 3 Non-algate ionically crosslinkable polycarboxylate polymers.

8. The composite material according to any one of claims 1 to 7, wherein the adhesive is selected from reactive adhesives based on acrylates, polyurethanes, epoxy resins, silicones, or water glass or other inorganic adhesive systems, or selected from thermoplastic adhesives based on PE, PP, PA, TPU, PLA, or other bio-based polymers, silicones, or any mixture of those adhesives.

9. A method for preparing a composite material comprising two or more layers, comprising the following steps: (i) Forming an adhesive layer (LB), (ii) Forming a layer (LA) containing aerogel particles with a diameter of 0.1 to 4 mm prior to any compression. (iii) By applying suitable conditions to achieve a stable bond between layers (LA) and (LB) and to form a layer portion (LA-1) containing both the adhesive and aerogel particles with a thickness of 0.01 to 1 mm and a layer portion (LA-2) without the adhesive with a thickness equal to or greater than 0.05 mm, a composite material comprising layers (LA) and (LB) is formed. The uncompressed aerogel particles of the layer (LA) preferably have one or more of the following characteristics (α) to (γ). (α) Porosity of 80-99.6%, (β) 15-200kg / m 3 The bulk density of the particles, (γ) The thermal conductivity of the loosely packed granular bed measured at 10 °C is 16-30 mW / mK.

10. The method according to claim 9, wherein the aerogel is a silica-based aerogel.

11. The method according to any one of claims 9 to 10, wherein the method comprises the following steps: (iv) Compression of the composite material, compressing the aerogel to 5-98% of its original thickness. (v) Apply a compression rate of 0.01-1 mm / sec.

12. The method according to any one of claims 9 to 11, wherein the thickness of the composite material is 0.1 to 20 mm.

13. The method according to any one of claims 9 to 12, wherein the thickness of the layer (LA) comprising aerogel particles is 0.1 to 4 mm.

14. The method according to any one of claims 9 to 13, wherein the adhesive is selected from acrylates, polyurethanes, epoxy resins, silicones, or thermoplastic adhesives such as PE, PP, PA, TPU, PLA.

15. The composite material according to any one of claims 1 to 8 or the composite material obtained or obtainable by any one of claims 9 to 14 is used as a thermal insulation material for buildings and structures, appliances, temperature-controlled logistics, cryogenic applications, automotive applications, infrastructure applications, marine applications, oil and gas applications or clothing, or as a thermal insulation material in batteries or a material that prevents heat transfer.

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