Composite article comprising aerogel particles, melamine resin and fibers

Abstract

The present invention relates to a method for producing a composite article comprising aerogel particles, a melamine resin, and fibers, and to a composite article obtained by this method, wherein the fibers are one or more selected from ceramic fibers, glass fibers, and melamine fibers.

Description

[Technical Field]

[0001] The present invention relates to a method for preparing a composite article comprising aerogel particles, a melamine resin and a fibrous blanket, and to the composite article obtained thereby. [Background technology]

[0002] For example, many industrial and architectural applications, such as passive fire protection of structural steel beams, require thermal insulation performance and heat resistance at extremely high temperatures. UL 1709 (Fast Rise Fire Test for Protective Materials for Structural Steel) requires a test temperature of 1093°C, and ISO 834 (Cellulose Fire Curve) requires a temperature of 1110°C after 180 minutes of testing. New insulation materials must be developed that can provide thermal insulation performance and heat resistance at temperatures above 1100°C.

[0003] Currently, various grades of ceramic fiber blankets are used as thermal insulation materials for applications exceeding 1000°C. However, variations in the chemical composition of ceramic fiber blankets result in different heat resistance temperatures. Therefore, ceramic fiber blankets based on alkaline earth silicates (AES) can withstand temperatures up to 1200°C, while ceramic fiber blankets based on aluminum oxide (AO) can withstand temperatures up to 1600°C. However, the various chemical compositions result in significant differences in the material costs of ceramic fiber blankets. The cost of aluminum oxide-based ceramic fiber blankets is typically about 20 times higher than that of alkaline earth silicate-based blankets. As the demand for heat resistance increases, material costs rise sharply. Summary of the Invention [Problem to be solved by the invention]

[0004] In view of the prior art, the present invention provides a ceramic fiber blanket with improved thermal insulation performance and heat resistance temperature at reduced cost. [Means for solving the problem]

[0005] The inventors have surprisingly found that this problem can be solved by incorporating aerogel into the ceramic fiber blanket after the fiber blanket is formed. This can be accomplished by preparing an aerogel composition containing aerogel powder, melamine-formaldehyde resin (which forms a cross-linked melamine resin after curing), and an organic solvent, and infusing it into the fiber blanket.

[0006] The inventors have surprisingly discovered that the thermal insulation performance of glass fiber blankets and melamine fiber blankets can also be improved by incorporating aerogel.

[0007] In aerogel inclusion materials (or aerogel-incorporated materials), it is generally desirable to use a binder to structurally reinforce the aerogel inclusion material and provide general benefits such as reduced dust emission and improved mechanical integrity. However, compatibility issues exist between the binder and components in the aerogel dispersion, such as the aerogel particles and solvent. In such cases, aerogel particle aggregation and / or binder molecule coagulation may occur, and thus the blend dispersion containing the aerogel particles and binder may not remain stable. Furthermore, the thermal decomposition of binders, especially organic binders, is a major problem for passive fire protection. If the heat release due to binder decomposition is too high, the fire resistance of the aerogel inclusion material will deteriorate. The present invention is based, inter alia, on the discovery that melamine-formaldehyde resins can be used as binders for such fibrous blankets without compromising the excellent suitability of these fibrous blankets for passive fire protection. It should be understood that any reference herein to a "fibrous blanket" is not limited to the plural, but also encompasses the presence of a singular "fibrous blanket."

[0008] Accordingly, in a first aspect, the present invention relates to a method for preparing a composite article comprising aerogel particles, a melamine resin and fibers, the fibers being one or more selected from ceramic fibers, glass fibers and melamine fibers, the method comprising: - providing a fibrous material comprising fibers, the fibers being one or more selected from ceramic fibers, glass fibers and melamine fibers; - providing an aerogel composition comprising an aerogel powder, a melamine-formaldehyde resin, and an organic solvent; combining the fibrous material with an aerogel composition; - partially or completely removing the organic solvent to obtain a composite article. The present invention comprises:

[0009] The invention further relates to a composite article obtainable by this method.

[0010] Additionally, the present invention relates to a composite article comprising aerogel particles, a melamine resin, and fibers, wherein the fibers are one or more selected from ceramic fibers, glass fibers, and melamine fibers, and the composite article can be obtained by injecting or impregnating a fibrous material comprising the fibers with an aerogel composition comprising aerogel powder, a melamine-formaldehyde resin, an organic solvent, and optionally an inorganic opacifying agent and / or a mineral filler, and then partially or completely removing the organic solvent to obtain the composite article.

[0011] In a further aspect, the present invention provides a composite pin comprising aerogel particles, a melamine resin, and fibers, wherein the fibers are one or more selected from ceramic fibers, glass fibers, and melamine fibers, and the composite pin satisfies the following requirements (i) to (vii): (i) The composite article contains less than 15% by weight of organic compounds other than melamine resin; (ii) at least 50% of the fibers in the composite article have a length of 5 mm or greater; (iii) The composite article contains less than 10% by weight of a binder other than a melamine resin; (iv) the composite article exhibits a total weight loss of less than 35 wt. % in thermogravimetric analysis (TGA) when heated in a nitrogen atmosphere from 30° C. to 1100° C. at a temperature increase of 10° C. / min; (v) the weight ratio of the one or more aerogels to the one or more fibers in the composite article (aerogel / fibers) is 1:8 or greater; (vi) the composite article has a burn-through time (or burn-through time or burn-through time) of 60 minutes or more, the burn-through resistance (or burn-through resistance or burn-through resistance) being determined by treating the composite article in the form of a 30 cm x 30 cm sheet 13 mm thick with a soldering torch at the center of its first major surface with a flame having a temperature of 1400°C, the burn-through time being the time from the start of the flame treatment until the center of the second major surface reaches a temperature of 1000°C; (vii) when the composite article is used in the form of a 20 cm x 50 cm sheet having a thickness of 13 mm and is treated across its first major surface for 180 minutes according to the temperature-time curve of ISO 834, the center of the second major surface has a temperature of less than 1000°C; This relates to composite articles that satisfy one or more of the following criteria: [Brief explanation of the drawings]

[0012] BRIEF DESCRIPTION OF THE DRAWINGS [Figure 1] Preparation of blend dispersions containing aerogel powder and melamine-formaldehyde resin: a) 14 wt% melamine-formaldehyde resin solution; b) 11 wt% aerogel dispersion; c) blend dispersion. [Figure 2] Impregnation of blend dispersion in melamine fiber blanket: a) Wet gel in blanket b) Pressureless drying c) Finished blanket d) Pressure drying e) Finished blanket [Figure 3] Structurally reinforced (or structurally reinforced) aerogel-embedded melamine fiber blanket: a) Unfilled - Unpressurized dried - Pressure dried b) Surface c) Cross section [Figure 4]Impregnation of blend dispersion in a 3.5 mm thick ceramic fiber blanket: a) Wet gel in blanket b) Pressurized drying c) Finished blanket d) Surface e) Cross section [Figure 5] Impregnation of blend dispersion in 8mm thick ceramic fiber blanket: a) Wet gel in blanket b) Pressurized drying c) Finished blanket d) Surface e) Cross section [Figure 6] Impregnation of blend dispersions in 1 mm thick ceramic fiber paper: a) Wet gel in CF paper b) Pressurized drying c) Finished blanket d) Surface [Figure 7] Coating reinforcement in structurally reinforced aerogel-embedded melamine fiber blankets: a) before coating, b) after coating [Figure 8] Soldering Torch Test Setup [Figure 9] 60-minute torch test of a structurally reinforced aerogel-embedded ceramic fiber blanket (raw blanket thickness 3.5 mm): a) structurally reinforced aerogel-embedded ceramic fiber blanket before torch treatment, b) after 60 minutes of torch treatment, c) torched area, d) rear view [Figure 10] Dust release behavior of a structure-reinforced aerogel-embedded melamine fiber blanket (11.6 mm thick) on a steel plate: a) The structure-reinforced aerogel-embedded melamine fiber blanket is shaken on the steel plate. b) After the dust release test, the steel plate surface remains clean. [Figure 11] Thermal conductivity of unfilled, unreinforced aerogel-embedded, and structurally reinforced aerogel-embedded ceramic fiber blankets (raw thickness 3.5 mm) [Figure 12] Compression behavior of unreinforced aerogel-embedded and reinforced aerogel-embedded ceramic fiber blankets (3.5 mm thick): a) unreinforced aerogel-embedded ceramic fiber blanket b) reinforced aerogel-embedded ceramic fiber blanket [Figure 13]Thermogravimetric analysis (TGA) of unreinforced aerogel-embedded and reinforced aerogel-embedded ceramic fiber blankets (3.5 mm thick): a) unreinforced aerogel-embedded ceramic fiber blanket; b) reinforced aerogel-embedded ceramic fiber blanket. DETAILED DESCRIPTION OF THE INVENTION

[0013] Definitions of terms used herein In the context of the present invention, the term "composite article" is understood to refer to any article containing one or more aerogel particles and one or more fibers. Accordingly, the term "composite" is not intended to be limiting other than the presence of aerogel particles, melamine resin, and fibers, where the fibers are one or more selected from ceramic fibers, glass fibers, and melamine fibers, which together form the article. It is understood that the aerogel particles, melamine resin, and fibers are not spatially separated. Rather, the aerogel particles and melamine resin are typically located between and around the fibers. Preferably, the one or more fibers form a woven or nonwoven structure within and around which the aerogel particles and melamine resin reside.

[0014] The composite article is typically in the form of a batt, nonwoven fabric, mat, felt, or blanket, such as a needled fiber blanket. Preferably, the aerogel particles are present in a nonwoven fiber blanket or a needled fiber blanket. The term "nonwoven fabric" should be understood to include needled fiber blankets. The composite article preferably has a thickness in the range of 3 mm to 500 mm, preferably in the range of 3 mm to 100 mm, more preferably in the range of 3 mm to 50 mm, and even more preferably in the range of 5 mm to 30 mm (for example, fiberboard). Alternatively, the composite article preferably has a thickness in the range of 0.1 mm to 30 mm, preferably in the range of 0.5 to 10 mm, more preferably in the range of 1 to 3 mm, and even more preferably in the range of 1 to less than 3 mm (also known as fiber paper). Generally, it is preferred that the composite article have a thickness of 1 to 30 mm. The extension in the other two dimensions is preferably at least 5 times the thickness in each case. The term "dimension" as used herein should be understood to refer to three known spatial dimensions that are mutually orthogonal (e.g., as understood by "three dimensions").

[0015] As used herein, the term "batting" refers to a layer or sheet of fibrous material, which typically comprises fibers.

[0016] As used herein, the term "nonwoven" refers to a material containing fibers that are not woven or knitted.

[0017] The term "nonwoven fiber blanket" is understood to relate to a material comprising fibers that are neither woven nor knitted, which material is in the form of a blanket.

[0018] The term "needled fiber blanket" is understood to relate to a material comprising fibers, the fibers being needled and the material being in the form of a blanket.

[0019] As used herein, the term "blanket" typically refers to an article that extends less in one dimension than in the other two. Preferably, it refers to a molded article that extends in only one dimension by up to 1000 mm, preferably by up to 500 mm, more preferably by up to 100 mm, but extends at least five times in each of the other two dimensions. In other words, the term "blanket" typically refers to a flat or rectangular article.

[0020] Unless otherwise specified, the use of the singular or plural should be understood to allow for the presence of "one or more" of the singular or plural noun. In particular, the term "fibrous material comprising fibers" refers to "fibrous material comprising one or more fibers." Similarly, the term "aerogel composition comprising aerogel powder, melamine-formaldehyde resin, and organic solvent" is understood to include cases where two or more (types of) aerogel powders and / or two or more (types of) melamine-formaldehyde resins and / or two or more (types of) organic solvents are included in the aerogel composition. Mixtures of different types of aerogel powders and / or mixtures of different types of organic solvents may also be used.

[0021] As used herein, the term "melamine-formaldehyde resin" or "melamine-formaldehyde binder" refers to an oligomer (or mixture of oligomers) derived primarily (typically at least 50% by weight) from melamine and formaldehyde, with formaldehyde acting as a crosslinker. Melamine typically reacts with formaldehyde under alkaline conditions to form a mixture of various oligomers, also known as methylolmelamine. Thus, "melamine-formaldehyde resin" or "melamine-formaldehyde binder" preferably refers to an oligomer containing at least 50% by weight, preferably 60% by weight, more preferably 70% by weight, even more preferably 80% by weight, even more preferably 90% by weight, or even more preferably 95% or 98% by weight of atoms derived from the reaction of melamine and formaldehyde. Upon further heating, such oligomers undergo condensation or readily react with thiol, hydroxyl, carboxyl, and amide groups to form three-dimensional thermosetting polymer networks. Their oligomeric nature makes them soluble in water or mixtures of water and organic solvents (i.e., the solubility is preferably greater than 5 g / L in a 1:1 weight ratio mixture of water and 2-propanol at 20°C). In differential scanning calorimetry (DSC), the DSC thermogram of a "melamine-formaldehyde resin" or "melamine-formaldehyde binder" typically exhibits an exothermic enthalpy in the temperature range of 100-200°C (preferably with an enthalpy integral in this range of 10 J·g). -1 A "melamine-formaldehyde resin" or "melamine-formaldehyde binder" is typically used in the manufacturing method of the present invention, while the final product typically includes a crosslinked product thereof, which is referred to herein as a "melamine resin" or a "crosslinked melamine-formaldehyde resin."

[0022] As used herein, the terms "melamine resin" or "crosslinked melamine-formaldehyde resin" refer to a polymer obtainable by crosslinking a "melamine-formaldehyde resin" or "melamine-formaldehyde binder." Crosslinking, also known as "curing," typically refers to heating at a temperature of at least 100°C, typically 120-180°C, for 1-8 hours. Thus, "melamine resin" or "crosslinked melamine-formaldehyde resin" preferably refers to a polymer that contains at least 50% by weight, preferably 60% by weight, more preferably 70% by weight, even more preferably 80% by weight, even more preferably 90% by weight, or even more preferably 95% or 98% by weight, of atoms derived from the reaction of melamine and formaldehyde. "Melamine resins" or "crosslinked melamine-formaldehyde resins" are typically crosslinked materials that are insoluble in water or in mixtures of water and organic solvents (i.e., the solubility is preferably less than 5 g / L in a 1:1 weight ratio mixture of water and 2-propanol at 20°C). Due to the nature of the crosslinking, DSC thermograms of "melamine resins" or "crosslinked melamine-formaldehyde resins" typically exhibit no exothermic enthalpy in the temperature range of 100-200°C (preferably, the enthalpy integral in this range is less than 10 J g -1 The definition of "melamine resin" also applies to the melamine in melamine fibres.

[0023] As used herein, the term "aerogel" refers to a porous material derived from a gel in which the liquid component of the gel has been essentially replaced by a gas without disrupting the gel structure. Preferably, the "aerogel" is a silica aerogel. Such silica aerogels typically have a density of 0.1 g / cm. 3 or less, preferably 0.05 g / cm 3 It has the following density and can be prepared by the known Stoeber process: In the present invention, "aerogel" is preferably a silica aerogel obtained according to the process described in EP 2 722 311 A2, preferably as defined in claim 22 thereof.

[0024] In the present invention, the term "aerogel particles" refers to silica aerogel particles, preferably obtainable according to the process described in EP 2 722 311 A2, preferably as defined in claim 22 thereof. Aerogel particles suitable for use in the present invention are commercially available, for example, as "Jios AeroVa", with "D20 grade" being preferred. "Jios AeroVa D20 grade" has a D95 particle size range of less than 20 μm, a density of 0.03-0.1 g / cm. 3 Bulk density of 0.017~0.022W / m·k, thermal conductivity of 600~800m 2 / g and a porosity of over 90%.

[0025] The term "heterophase reaction" preferably refers to a reaction carried out in a system containing two or more phases, for example a system consisting of two immiscible phases, namely an aqueous phase and a phase that is not miscible with the aqueous phase, preferably a non-polar solvent phase. The reaction, i.e. the formation of the initial structure, begins at the interface of the different phases. It is therefore not relevant to reactions in which all reactants are dissolved in the same solvent. Examples of "heterophase reactions" are emulsion reactions, suspension reactions or dispersion reactions.

[0026] The term "ceramic" preferably refers to any material that is inorganic, non-metallic, and preferably amorphous. It typically relates to one or more inorganic materials selected from oxides, nitrides, and carbides, including mixtures thereof. Preferably, a "ceramic" material comprises at least 90% by weight (preferably at least 95% by weight, more preferably at least 99% by weight) of one or more of silicon, aluminum, cerium, zirconium, and / or alkaline earth metals.

[0027] As used herein, the term "fiber" preferably refers to an article that extends in a first dimension at least 10 times longer than in any of the other two dimensions. The first dimension preferably corresponds to the length of the fiber. The fiber is one or more selected from ceramic fibers, glass fibers, and melamine fibers. Preferably, the fibers include ceramic fibers, and optionally glass fibers and / or melamine fibers. More preferably, at least 50% by weight of the fibers are ceramic fibers, with the remainder being glass fibers and / or melamine fibers. Even more preferably, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or even at least 98% by weight of the fibers are ceramic fibers, based on the total amount of fibers in the composite article of the present invention. Similarly, preferably, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or even at least 98% by weight of the fibers in the fibrous article used in the present invention are ceramic fibers, based on the total amount of fibers in the fibrous article. It is particularly preferred that the fibers are ceramic fibers.

[0028] The term "fibrous article" refers to any article containing one or more fibers. Examples include batting, nonwoven fabrics, mats, felts, and needled fiber blankets. Preferred examples are nonwoven fiber blankets or needled fiber blankets. The fibrous article preferably has a thickness in the range of 0.1 mm to 500 mm. For example, the fibrous article may have a thickness in the range of 3 mm to 500 mm, preferably in the range of 3 to 100 mm, more preferably in the range of 3 to 50 mm, and even more preferably in the range of 5 to 30 mm (e.g., in the case of fiberboard). Alternatively, the fibrous article preferably has a thickness in the range of 0.1 mm to 30 mm, preferably in the range of 0.5 to 10 mm, more preferably in the range of 1 to 3 mm, and even more preferably in the range of 1 to less than 3 mm (also known as fiber paper). Generally, the fibrous article preferably has a thickness of 1 to 30 mm.

[0029] As used herein, the term "aerogel composition" refers to any mixture comprising aerogel powder, melamine-formaldehyde resin, and an organic solvent. Preferably, the "aerogel composition" is a mixture comprising aerogel powder and melamine-formaldehyde resin dispersed in an organic solvent. In other words, the "aerogel composition" is preferably an "aerogel dispersion."

[0030] The term "dispersion" as used herein preferably relates to a mixture in which solid particles of one material are dispersed in a continuous phase of another material, which is a liquid. The terms solid and liquid as used herein refer to the state of the materials at a temperature of 25° C. and a pressure of 1 atmosphere. "Dispersed" preferably refers to a state in which the particles do not readily settle in the liquid continuous phase.

[0031] As used herein, the term "organic solvent" refers to any organic compound that is liquid at a temperature of 20°C and a pressure of 1 atmosphere. Preferred examples of organic solvents include hydrocarbon solvents and alcohols, including mixtures thereof. Hydrocarbons are understood to be organic compounds consisting of carbon and hydrogen atoms.

[0032] It should be understood that the term "removing the organic solvent" preferably also includes removing the water, and may also include curing (typically cross-linking) the melamine-formaldehyde resin.

[0033] The term "organic compound" as used herein relates to any compound containing at least one carbon-hydrogen bond. When calculating the content of organic compounds in the product of the present invention, melamine-formaldehyde resin is preferably not considered as an organic compound.

[0034] In this specification, terms such as "comprise" or "contain," as in "A comprises B," are used to openly express definitions of compositions and the like. Thus, "A comprises B" is understood to indicate that A includes at least B, but may further include any number and amounts of other components. In contrast, the term "consists of" in "A consists of B" generally indicates that A does not include any components other than B.

[0035] For example, a term such as "preferably" indicates that a certain feature may or may not be met. Thus, such a term precedes an optional feature. Generally, when the feature is met, an additional beneficial effect is expected.

[0036] As used herein, the term "injecting" refers to the act of introducing (typically by application of force) a fluid (such as, for example, an aerogel composition) into a solid material (such as, for example, a fiber). Suitable approaches for "injecting" are described, for example, in EP 3 023 528 A1.

[0037] As used herein, the terms "impregnating" or "soaking" refer to the act of introducing (typically without force) a fluid (such as, for example, an aerogel composition) into a solid, porous material (such as, for example, a fibrous material). "Impregnating" or "soaking" can be accomplished, for example, by either placing the article to be impregnated or immersed in a container that typically contains the liquid material to impregnate the article, or by pouring a liquid onto the article to be impregnated or immersed.

[0038] As used herein, the term "binder" refers to any material intended to provide adhesion between two solid materials. Preferably, the term "binder" refers to any material that serves to bind aerogel particles to each other and / or to fibers. Binders may be organic or inorganic in nature. Specific examples of binders include, but are not limited to, water glass, silicone-based binders, and phenolic resin-based binders. Melamine-formaldehyde resins may function as binders.

[0039] Detailed Description of the Invention The present invention relates to a method for preparing a composite article comprising aerogel particles, a melamine resin, and fibers, and to a composite article obtained by this method, wherein the fibers are one or more selected from ceramic fibers, glass fibers, and melamine fibers.

[0040] method The present invention relates to a method for preparing a composite article comprising aerogel particles, a melamine resin, and fibers, the fibers being one or more selected from ceramic fibers, glass fibers, and melamine fibers, the method comprising: - providing a fibrous material comprising fibers, the fibers being one or more selected from ceramic fibers, glass fibers and melamine fibers; - providing an aerogel composition comprising an aerogel powder, a melamine-formaldehyde resin, and an organic solvent; combining the fibrous material with an aerogel composition; - partially or completely removing the organic solvent to obtain a composite article. The present invention comprises:

[0041] The method is not limited to these steps, and may include any number of additional steps before, between, or after each of these steps. Thus, the steps above are not necessarily sequential. However, it is preferred to perform them in the order specified. Furthermore, it is preferred that the steps be sequential.

[0042] As will be appreciated by those skilled in the art, the aerogel powder and the melamine-formaldehyde resin do not necessarily have to be applied (or coated) at the same time (although this is preferred), but the aerogel powder and the melamine-formaldehyde resin can also be applied in the form of separate compositions, each containing an organic solvent. For example, the last three steps can be combined into the following six steps: - providing an aerogel composition comprising an aerogel powder and an organic solvent; - combining the fibrous material and the aerogel composition; - partial or complete removal of the organic solvent to obtain a composite article; - providing a resin composition comprising a melamine-formaldehyde resin and an organic solvent; - combining the fibrous material and the resin composition; and - partial or complete removal of the organic solvent to obtain a composite article; Or follow these five steps: - providing an aerogel composition comprising an aerogel powder and an organic solvent; - providing a resin composition comprising a melamine-formaldehyde resin and an organic solvent; - combining the fibrous material with the aerogel composition and the resin composition in any order; and - Partial or complete removal of the organic solvent to obtain a composite article It is also envisaged that it may be replaced by

[0043] Each of the steps of the methods described herein may include additional operations. For example, the step of providing an aerogel composition including aerogel powder, melamine-formaldehyde resin, and an organic solvent may include providing an aerogel composition including additional components other than the aerogel powder, melamine-formaldehyde resin, and the organic solvent. Furthermore, the step of combining the fibrous material and the aerogel composition may include combining not only the fibrous material and the aerogel composition, but also additional molded articles, compositions, etc.

[0044] The fibers and the aerogel composition are preferably combined by injecting, soaking, or impregnating the fibers with the aerogel composition, more preferably by impregnating the fibers with the aerogel composition. Suitable methods for injecting such compositions are known to those skilled in the art and are described, for example, in EP 3 023 528 A1.

[0045] Preferably, partially or completely removing the organic solvent by drying to obtain the composite article comprises drying at a temperature of 50 to 170°C for 1 to 8 hours, optionally followed by drying at 171 to 230°C for 1 to 48 hours.

[0046] For example, partial or complete removal of the organic solvent can be carried out at a temperature of 120-230°C, e.g., in a hot air oven under atmospheric pressure or mechanical pressure. Following this approach, both drying and curing can be carried out in a single step. Alternatively, drying can be carried out at a temperature of 50°C to less than 120°C, e.g., in a hot air oven under atmospheric pressure or mechanical pressure, followed by curing at a temperature of 120-230°C, preferably 140-230°C, e.g., in a hot press. The pressure during the curing step is preferably in the range of 10-500 bar, more preferably 20-300 bar.

[0047] Composite articles obtained by this method The composite article obtained by the method of the present invention preferably contains 15 to 70 wt. % aerogel based on the total weight of the composite article, more preferably 20 to 60 wt. % aerogel, and even more preferably 30 to 50 wt. % aerogel based on the total weight of the composite article.

[0048] The composite article obtained by the method of the present invention further preferably contains 0.1 to 20 wt. % melamine resin based on the total weight of the composite article, more preferably 0.5 to 15 wt. %, even more preferably 1 to 12 wt. %, and even more preferably 3 to 10 wt. % melamine resin based on the total weight of the composite article.

[0049] The composite article preferably has a thickness in the range of 3 mm to 500 mm, preferably in the range of 3 mm to 100 mm, more preferably in the range of 3 mm to 50 mm, and even more preferably in the range of 5 mm to 30 mm (for example in the case of fiberboard). Alternatively, the composite article preferably has a thickness in the range of 0.1 mm to 30 mm, preferably in the range of 0.5 to 10 mm, more preferably in the range of 1 to 3 mm, and even more preferably in the range of 1 mm to less than 3 mm (which may also be called fiber paper). In general, it is preferred that the composite article have a thickness of 1 to 30 mm.

[0050] If the width of the composite article is W, the length of the composite article is L, and the thickness of the composite article is T, the composite article preferably meets the following requirements:

number

[0051] To achieve excellent flame retardancy, the composite article typically contains less than 15 wt. % of organic compounds, preferably less than 10 wt. % of organic compounds, more preferably less than 5 wt. % of organic compounds, even more preferably less than 2 wt. % of organic compounds, even more preferably less than 1 wt. % of organic compounds, and most preferably less than 0.5 wt. % of organic compounds, based on the total weight of the composite article. The term organic compound typically relates to any compound containing at least one carbon-hydrogen bond. In this context, the term organic compound should be understood to exclude melamine resins.

[0052] The method of the present invention can ensure that at least 50% of the fibers in the composite article have a length of 5 mm or greater. Preferably, at least 50% of the fibers in the composite article have a length of 10 mm or greater, more preferably, at least 75% of the fibers in the composite article have a length of 5 mm or greater, even more preferably, at least 75% of the fibers in the composite article have a length of 10 mm or greater, even more preferably, at least 75% of the fibers in the composite article have a length of 15 mm or greater, and most preferably, at least 75% of the fibers in the composite article have a length of 20 mm or greater.

[0053] To improve flame retardancy and cost, composite articles typically contain less than 10 wt. % of binders other than melamine resins, preferably less than 5 wt. % of binders other than melamine resins, more preferably less than 2 wt. % of binders other than melamine resins, even more preferably less than 1 wt. % of binders other than melamine resins, even more preferably less than 0.5 wt. % of binders other than melamine resins, and most preferably less than 0.1 wt. Furthermore, reducing the amount of binders other than melamine resins can be beneficial to the flame retardancy, cohesion, and insulating properties of the composite article because more fibers and / or aerogels can be incorporated into the composite article. Prior art methods generally require the use of binders other than melamine resins to ensure the structural integrity of the composite article by binding the fibers to each other and to the filler. In the present invention, the amount of binder can be significantly reduced because fibrous materials can be used as starting materials instead of a slurry of fibers and fillers.

[0054] By using the method of the present invention, the composite article may exhibit, in thermogravimetric analysis (TGA), a total weight loss when heated in a nitrogen atmosphere from 30°C to 1100°C at a temperature ramp rate of 10°C / minute of less than 35 wt%, preferably less than 30 wt%, more preferably less than 25 wt%, even more preferably less than 20 wt%, even more preferably less than 15 wt%, and most preferably less than 10 wt%, based on the total weight of the composite article prior to thermogravimetric analysis.

[0055] Furthermore, it is possible to achieve a weight ratio of one or more aerogels to one or more fibers (aerogel / fibers) in the composite article of 1:8 or greater, preferably 1:4 or greater, more preferably 1:2 or greater, and even more preferably 1:1 or greater. Prior art methods, which are typically based on drying a dispersion of fibers, severely limit the amount and length of fibers that can be stably incorporated into a fiber blanket due to the need to use significant amounts of binder.

[0056] The composite article may further comprise an inorganic opacifying agent and / or a mineral filler. Thus, the step of providing an aerogel composition comprising an aerogel powder, a melamine-formaldehyde resin, and an organic solvent is preferably a step of providing an aerogel composition comprising an aerogel powder, a melamine-formaldehyde resin, an organic solvent, and an inorganic opacifying agent and / or a mineral filler.

[0057] fibrous material The fibrous material is preferably selected from batting, nonwoven fabric, mat, felt and needled fibrous blanket, which are preferably prepared via an air-laying process or a carding process, and the fibrous material is preferably a nonwoven fibrous blanket or a needled fibrous blanket.

[0058] The fibrous material preferably contains 90% by weight or more, more preferably 95% by weight or more, and even more preferably 98% by weight or more of the total of ceramic fibers, glass fibers, and melamine fibers.

[0059] When ceramic fibers are preferred, typically at least 50 wt.%, preferably at least 60 wt.%, more preferably at least 70 wt.%, even more preferably at least 80 wt.%, even more preferably at least 90 wt.%, even more preferably at least 95 wt.%, even more preferably at least 98 wt.%, and even more preferably all of the fibers in the fibrous material and / or composite article are ceramic fibers.

[0060] When glass fibers are preferred, typically at least 50% by weight, preferably at least 60% by weight, more preferably at least 70% by weight, even more preferably at least 80% by weight, even more preferably at least 90% by weight, even more preferably at least 95% by weight, even more preferably at least 98% by weight, and even more preferably all of the fibers in the fibrous material and / or composite article are glass fibers.

[0061] When melamine fibers are preferred, typically at least 50% by weight, preferably at least 60% by weight, more preferably at least 70% by weight, even more preferably at least 80% by weight, even more preferably at least 90% by weight, even more preferably at least 95% by weight, even more preferably at least 98% by weight, and even more preferably all of the fibers in the fibrous material and / or composite article are melamine fibers.

[0062] Fibrous material: 20-300kg / m 3k , preferably 50 to 200 kg / m 3 , more preferably 80 to 150 kg / m 3 It is more preferred that the density of the polymer is 0.05 to 0.15.

[0063] Preferred examples of fibrous materials for use in the present invention are (amounts in % by weight): Uniflex Fiberflax Duraback has a recommended operating temperature of 982°C and a density of 64 kg / m 3 (typically available with a chemical composition including 31-35% Al2O3, 50-54% SiO2, 25% ZrO, 1.30% Fe2O3, 1.70% TiO2, 0.50% MgO, and up to 7.5% CaO); Uniflax Fiberflax DuraBlanket S has a recommended use temperature of 1177°C and is available in densities of 64, 96 and 128 kg / m 3 (typically available with a chemical composition of 43-47% Al2O3, 53-57% SiO2, less than 1% Fe2O3, and less than 1% TiO2); Uniflex Fiberflax DuraBlanket HP-S has a recommended use temperature of 1204°C and is available in densities of 64, 96 and 128 kg / m 3 (typically with a chemical composition containing 43-47% Al2O3 and 53-57% SiO2); Uniflex Fiberflax DuraBlanket 2600 has a recommended use temperature of 1343°C and is available in densities of 96 and 128 kg / m 3of (typically with a chemical composition including 29-31% Al2O3, 53-55% SiO2, and 15-17% ZrO2); Uniflex Fiberflax PH Blanket has a recommended operating temperature of 1177°C and a density of 96 kg / m 3 (typically with a chemical composition including 43-47% Al2O3, 53-55% SiO2, less than 1% Fe2O3, and less than 1% TiO2); Uniflex Fiberflax Moist Pack-D has a recommended operating temperature of 1010°C and a density of 190-290 kg / m 3 (typically with a chemical composition containing 23-32% Al2O3 and 68-77% SiO2); Uniflax Fiberflax Fiber Mat Blanket has a recommended use temperature of 677°C and a density of 88 kg / m 3 (typically with a chemical composition including 29-47% Al2O3, 52-57% SiO2, and less than 18% ZrO2); Uniflax Fibermax Mat has a recommended use temperature of 1566°C and a density of 24 kg / m 3 (typically available with a chemical composition including Al2O3 72%, SiO2 27%, Fe2O3 0,02%, TiO2 0,001%, MgO 0,05%, CaO 0,05%); Uniflax FiberMax Needled Blanket has a recommended operating temperature of 1600°C and is available in densities of 100 and 130 kg / m 3 (typically available with a chemical composition including Al2O3 72%, SiO2 27%, Fe2O3 0,02%, TiO2 0,001%, MgO 0,05% and CaO 0,05%); Uniflux's Insulflux LTX blanket has a recommended operating temperature of 1100°C and densities of 64, 96, 128, and 160 kg / m 3(typically with a chemical composition including less than 1% Al2O3, 61-67% SiO2, less than 0.6% Fe2O3, 2.5-6.5% MgO, and 27-33% CaO); Uniflux's Insulflux S blanket has a recommended operating temperature of 1100°C and is available in densities of 64, 96 and 128 kg / m 3 (typically with a chemical composition including 61-67% SiO2, 2-7% MgO, and 27-33% CaO); Uniflax's Isoflux 1400 blanket has a recommended operating temperature of 1300°C and is available in densities of 96, 128 and 160 kg / m 3 (typically with a chemical composition containing 70-80% SiO2 and 18-27% MgO); KCC's "Cerakuwool New Bio" has densities of 96, 128 and 160 kg / m 3 (typically with a chemical composition including less than 31% Al2O, 58-67% SiO2, 2-8% MgO, and 26-34% CaO); Newfire's Super Wooplus Blanket SPB has a recommended operating temperature of 1050°C and densities of 96 and 128 kg / m 3 (typically with a chemical composition including 62-68% SiO2, 3-7% MgO, and 26-32% CaO); Uniflux's Safil Blanket & Mat has a recommended operating temperature of 1600°C and a density of 35.96 kg / m 3 (typically with a chemical composition containing 95-97% Al2O3 and 3-5% SiO2); Frenzelitt's Isotame S Breeze has a recommended use temperature of 1100°C (typically has a chemical composition containing more than 94% SiO2); Uniflax's Insulflux paper has a recommended use temperature of 1200°C (typically with a chemical composition including 61-67% SiO2, less than 1% Al2O3, 2.5-6.5% MgO, and 27-33% CaO); Li Feng Jin's E-glass fiber needle mat has a recommended use temperature of 650°C (typically has a chemical composition including 52-56% SiO2, 12-16% Al2O3, 0-6% MgO, 15-25% CaO, 4-9% B2O3, and 0-1% Na2O+K2O); Frenzelitt's Isoglass needle mat has a recommended use temperature of 550°C (typically has a chemical composition including 52-56% SiO2, 12-16% Al2O3, 0-6% MgO, and 15-25% CaO, 6-13% B2O3, and 0.3-2% Na2O); Smart Melamine Doo's meltblown melamine nonwoven blanket has a recommended use temperature of 240°C (typically has a chemical composition containing more than 99% melamine resin).

[0064] Among these, the following are preferred: Fiberflax Duraback, Fiberflax DuraBlanket S, Fiberflax DuraBlanket 2600, Fiberflax Moist Pack-D, FiberMax Needled Blanket, Insulflax LTX Blanket, Insulflax S Blanket, Isoflax 1400 Blanket, Safil Blanket & Mat, Isotame S Breeze, Insulflax Paper, E-Glass Fiber Needled Mat, Isoglass Needled Mat, Meltblown Melamine Nonwoven Blanket (Smart Melamine).

[0065] Ceramic fiber Ceramic fibers can generally be structured into three types of fibers. a) ceramic fibers containing 80% or more by weight of alumina; b) ceramic fibers containing 2 to less than 80% by weight of alumina; and c) Ceramic fibers containing less than 2% by weight of alumina.

[0066] a) ceramic fibers of 80% by weight or more alumina: This first type of ceramic fiber typically contains 80 wt. % or more alumina, preferably 85 wt. % or more alumina, preferably 90 wt. % or more alumina, preferably 95 wt. % or more alumina, based on the total weight of the ceramic fiber, and the alumina content is preferably 99 wt. % or less, more preferably 98 wt. % or less, and even more preferably 97 wt. % or less, based on the total weight of the ceramic fiber.

[0067] The ceramic fibers may further contain 0 to 20 wt% silica, preferably 1 to 20 wt% silica, more preferably 1 to 15 wt% silica, even more preferably 1 to 10 wt% silica, and even more preferably 2 to 6 wt% silica, based on the total weight of the ceramic fibers.

[0068] These ceramic fibers preferably contain less than 2 wt. % of components other than silica and alumina, preferably less than 1 wt. % of components other than silica and alumina, and more preferably less than 0.5 wt. % of components other than silica and alumina, based on the total weight of the ceramic fibers.

[0069] b) Ceramic fibers containing 2 to 80% by weight of alumina: This second type of ceramic fiber typically contains 2 to 80 wt. % alumina, preferably 15 to less than 80 wt. % alumina, and more preferably 20 to 75 wt. % alumina, based on the total weight of the ceramic fiber.

[0070] The ceramic fibers may further contain 10 to 98% by weight of silica, preferably 15 to 90% by weight of silica, more preferably 20 to 85% by weight of silica, and even more preferably 25 to 80% by weight of silica, based on the total weight of the ceramic fibers.

[0071] For example, the ceramic fibers may comprise 30-35 wt% alumina, 50-55 wt% silica, and 4-20 wt% of the sum of ZrO2, Fe2O3, TiO2, MgO, and CaO, based on the total weight of the ceramic fibers. Alternatively, the ceramic fibers may comprise 42-48 wt% alumina and 52-58 wt% silica, based on the total weight of the ceramic fibers. Furthermore, the ceramic fibers may comprise 28-32 wt% alumina, 52-56 wt% silica, and 14-18 wt% ZrO2, based on the total weight of the ceramic fibers. Alternatively, the ceramic fibers may comprise 22-34 wt% alumina and 66-78 wt% silica, based on the total weight of the ceramic fibers. In a further alternative example, the ceramic fibers may comprise 66-78 wt% alumina and 22-34 wt% silica, based on the total weight of the ceramic fibers.

[0072] These ceramic fibers preferably contain less than 2% by weight of components other than those listed above, preferably less than 1% by weight of components other than those listed above, and even more preferably less than 0.5% by weight of components other than those listed above, based on the total weight of the ceramic fibers.

[0073] c) Ceramic fibers containing less than 2% by weight of alumina Ceramic fibers of this type typically contain less than 2 wt. % alumina, preferably less than 1 wt. % alumina, and more preferably less than 0.5 wt. % alumina, based on the total weight of the ceramic fibers. Alumina may be absent from these ceramic fibers.

[0074] These ceramic fibers typically contain 50-85 wt% silica and 15-50 wt% alkaline earth metal oxide, preferably 55-85 wt% silica and 15-45 wt% alkaline earth metal oxide, and more preferably 60-82 wt% silica and 18-40 wt% alkaline earth metal oxide, based on the total weight of the ceramic fibers. Alternatively, this type of ceramic fiber may contain 55-72 wt% silica and 28-45 wt% alkaline earth metal oxide, preferably 60-70 wt% silica and 30-40 wt% alkaline earth metal oxide, based on the total weight of the ceramic fibers. Another type of these ceramic fibers contains 65-85 wt% silica and 15-35 wt% alkaline earth metal oxide, preferably 70-80 wt% silica and 20-30 wt% alkaline earth metal oxide, based on the total weight of the ceramic fibers.

[0075] The alkaline earth metal oxide is preferably selected from MgO and CaO or a combination thereof, and the proportion of CaO in the alkaline earth metal oxide is preferably 75% by weight or more, more preferably 85% by weight or more, based on the total amount of alkaline earth metal oxide.

[0076] In any of the ceramic fibers described herein, the content of components other than those listed in the ceramic fiber is preferably less than 2 wt %, more preferably less than 1 wt %, and even more preferably less than 0.5 wt %, based on the total weight of the ceramic fiber.

[0077] Glass fiber Known types of glass fibers include, for example, A-glass, C-glass, D-glass, E-glass, M-glass, and S-glass. In the present invention, E-glass is preferably used. E-glass and S-glass fibers usually have a low (MgO+Al2O3) content, while the content of these in R-glass fibers is typically at least 25% by weight.

[0078] E-glass typically contains 50-60 wt% SiO2, 10-18 wt% Al2O3, 0-8 wt% MgO, 12-28 wt% CaO, and 2-15 wt% B2O3. E-glass preferably contains 52-56 wt% SiO2, 12-16 wt% Al2O3, 0-6 wt% MgO, 15-25 wt% CaO, and 4-13 wt% B2O3. Such E-glass may also be called aluminoborosilicate glass. E-glass may further contain alkali oxides, particularly Na2O and K2O. However, the alkali oxide content is typically limited to 3 wt% or less, preferably 2 wt% or less, and more preferably 1 wt% or less.

[0079] melamine fiber The melamine fibers preferably contain at least 50% by weight of polymer units derived from the reaction of melamine and formaldehyde, preferably 60% by weight, more preferably 70% by weight, even more preferably 80% by weight, even more preferably 90% by weight, or even more preferably 95% or 98% by weight. Most preferred melamine fibers contain 99% by weight of melamine resin.

[0080] solvent The organic solvent used in the process of the present invention is typically a hydrocarbon solvent, preferably a C 3-16 selected from saturated, unsaturated or partially saturated hydrocarbons or mixtures thereof, more preferably C 3-10 selected from saturated linear, branched or cyclic hydrocarbons or mixtures thereof, more preferably C 3-10 selected from linear or branched alkanes or mixtures thereof, and even more preferably C 5-7 It is selected from linear or branched alkanes or mixtures thereof, even more preferably from hexane or heptane or mixtures thereof, most preferably n-hexane.

[0081] Alternatively, the organic solvent used in the present invention is an alcohol solvent, preferably C 2-12is selected from saturated, unsaturated or partially saturated alcohols or mixtures thereof, more preferably C 2-12 is selected from saturated linear, branched or cyclic alcohols or mixtures thereof, more preferably C 2-12 is selected from saturated linear, branched or cyclic monohydric alcohols or mixtures thereof, even more preferably C (such as ethanol, 1-propanol, 2-propanol, butanol, pentanol (including cyclopentanol) or hexanol (including cyclohexanol)). 2-6 The organic solvent used in the present invention is preferably an alcohol solvent, selected from saturated linear, branched or cyclic monohydric alcohols or mixtures thereof, even more preferably selected from propanol or mixtures thereof, most preferably 2-propanol.

[0082] Additionally, the organic solvent may be a mixture of one or more hydrocarbon solvents and one or more alcohol solvents as set forth above.

[0083] aerogel The aerogel may be any inorganic aerogel. Preferably, the aerogel comprises or consists of one or more selected from silicon oxide, aluminum oxide, zirconium oxide, titanium oxide, hafnium oxide, and yttrium oxide. More preferably, the aerogel comprises or consists of silicon oxide. Even more preferably, the aerogel is a silica aerogel.

[0084] Aerogels typically have a porosity of 85% or greater, and more preferably 90% or greater, as determined by adsorption-desorption isotherms. More specifically, porosity is determined by measuring the pore volume and pore size distribution of the aerogel using the Barret-Joyner-Halenda (BJH) adsorption-desorption isotherm method.

[0085] The specific surface area of ​​aerogel is typically 300 m 2 / g or more. Preferably, the specific surface area is greater than 400 m when determined according to DIN ISO 9277 2003-05 (Determination of the specific surface area of ​​solids by gas adsorption using the BET method). 2 / g or more, preferably 500m 2 / g or more, preferably 600m 2 / g or more, preferably 2000m 2 / g or less, more preferably 1500m 2 / g or less, more preferably 1000m 2 / g or less, and even more preferably 800m 2 / g or less.

[0086] In the present invention, the aerogel powder preferably has a median particle size (d50) in the range of 1 to 50 μm, preferably 5 to 40 μm, more preferably 10 to 30 μm, and even more preferably 15 to 25 μm, as measured by laser diffraction, preferably using a Malvern Mastersizer.

[0087] The aerogel powder may be obtained, for example, by a heterogeneous reaction. In such a case, the aerogel powder is preferably a silica aerogel powder obtained by mixing and reacting deionized water, water glass, an organosilane compound, an inorganic acid, and an organic solvent, preferably a nonpolar organic solvent, to obtain silica hydrogel primary particles. The silica hydrogel primary particles are then subjected to solvent exchange, and the solvent-exchanged gel particles are dried under atmospheric pressure to obtain silica aerogel powder. Preferably, further grinding and sieving are not performed. Such heterogeneous reaction methods are known to those skilled in the art and are described, for example, in EP 2 722 311.

[0088] The aerogel powder is preferably prepared in the form of particles instead of monoliths. Therefore, the aerogel powder used in the present invention is preferably obtained by a process that does not involve grinding of the aerogel material. More preferably, the aerogel powder is in the form of primary particles (optionally including secondary particles). Therefore, no grinding or sieving process is required to produce the aerogel powder. Furthermore, the aerogel powder is preferably dried under normal pressure, e.g., 1 atmosphere, instead of using a supercritical drying process that is sometimes employed in the production of aerogels according to the prior art.

[0089] Aerogel composition The aerogel composition includes aerogel powder, melamine-formaldehyde resin, and an organic solvent. The aerogel composition preferably further includes water. The water content in the aerogel composition is preferably in the range of 1 to 30 wt %, more preferably in the range of 3 to 22 wt %, even more preferably in the range of 5 to 20 wt %, even more preferably in the range of 8 to 18 wt %, and even more preferably in the range of 11 to 17 wt %, based on the total weight of the aerogel composition. It should be understood that the aerogel composition may include additional components. To achieve efficient distribution of the aerogel powder and melamine-formaldehyde resin in the fibrous material, the aerogel composition is preferably a dispersion of the aerogel powder and melamine-formaldehyde resin in an organic solvent (and optionally water). The organic solvent is preferably an alcohol solvent as defined above.

[0090] The aerogel composition typically contains 2 to 20 wt% aerogel, preferably 4 to 15 wt% aerogel, more preferably 5 to 12 wt% aerogel, and even more preferably 6 to 10 wt% aerogel, based on the total weight of the aerogel composition. The aerogel composition further typically contains 0.1 to 20 wt% melamine-formaldehyde resin, preferably 0.1 to 10 wt% melamine-formaldehyde resin, more preferably 0.5 to 8 wt% aerogel melamine-formaldehyde resin, and even more preferably 1 to 7 wt% melamine-formaldehyde resin, based on the total weight of the aerogel composition. The remainder is preferably an organic solvent, optionally water.

[0091] The aerogel composition is preferably obtained by mixing composition A, which contains aerogel and a first solvent, with composition B, which contains a melamine-formaldehyde resin and a second solvent. The first solvent preferably contains at least 90% by weight of isopropanol. The second solvent is preferably a mixture of isopropanol and water, more preferably 40-80% by weight of isopropanol and 60-20% by weight of water, preferably 50-80% by weight of isopropanol and 50-20% by weight of water, more preferably 60-70% by weight of isopropanol and 40-30% by weight of water. The weight ratio of composition A to composition B is preferably in the range of 20:1 to 1:2, more preferably 15:1 to 1:1, even more preferably 10:1 to 1:1, and even more preferably 7:1 to 1:1. Therefore, the water content (or water content) in the aerogel composition is preferably in the range of 1 to 30 wt %, more preferably in the range of 3 to 22 wt %, even more preferably in the range of 5 to 20 wt %, still more preferably in the range of 8 to 18 wt %, and even more preferably in the range of 11 to 17 wt %, based on the total weight of the aerogel composition.

[0092] The weight ratio of aerogel to melamine-formaldehyde resin in the aerogel composition is preferably in the range of 1:10 to 100:1, more preferably 1:5 to 50:1, even more preferably 1:2 to 20:1, even more preferably 1:2 to 10:1, most preferably 1:1 to 8:1, and even more preferably 1:1 to 7:1. The same ratio preferably applies to the composite article.

[0093] The total content of the aerogel powder, melamine-formaldehyde resin, organic solvent, and optionally water in the aerogel composition is preferably 90% by weight or more, preferably 95% by weight or more, more preferably 97% by weight or more, even more preferably 98% by weight or more, still more preferably 99% by weight or more, most preferably 99.5% by weight or more, or even more preferably 99.8% by weight or more, based on the total weight of the aerogel composition.

[0094] Alternatively, when this method includes the use of an inorganic opacifying agent and / or mineral filler, the aerogel composition is preferably a dispersion of aerogel powder, melamine-formaldehyde resin, inorganic opacifying agent, and / or mineral filler in an organic solvent. Other components may or may not be included in the aerogel composition. The inorganic opacifying agent typically comprises or consists of one or more selected from iron oxide, zirconium oxide, titanium oxide, silicon carbide, and graphite (graphite is preferably present in the composite article in an amount of less than 5 wt. %, preferably less than 2 wt. %, and more preferably less than 1 wt. %, based on the total weight of the composite article). Among these, iron oxide, zirconium oxide, titanium oxide, and / or silicon carbide are preferred. Preferably, the inorganic opacifying agent comprises or consists of one or more selected from iron oxide, zirconium oxide, and silicon carbide, and more preferably, the inorganic opacifying agent is iron oxide or silicon carbide.

[0095] The mineral filler preferably comprises or consists of one or more selected from metal hydroxides and hydrated carbonates. Preferably, the mineral filler comprises or consists of one or more selected from aluminum hydroxide, magnesium hydroxide, hydromagnesite, and hydrocalcite. More preferably, the mineral filler is one or both selected from magnesium dihydroxide and aluminum trihydroxide.

[0096] Preferably, the inorganic opacifying agent and the mineral filler are not in the form of an aerogel. Particularly preferred is when the inorganic opacifying agent, more preferably the mineral filler, has a bulk density of at least 0.1 g / cm, as tested according to DIN EN ISO 787-11. 3 and / or the inorganic opacifying agent, more preferably the mineral filler, has a specific surface area of ​​300 m, as tested according to DIN ISO 9277 2003-05 (BET method). 2 / g or less. Alternatively or additionally, it is further preferred that the inorganic opacifying agent, more preferably the mineral filler, is chemically distinct from the material used as the aerogel. It is understood that any combination of the inorganic opacifying agents and mineral fillers mentioned herein can be used.

[0097] When containing an inorganic opacifying agent and / or mineral filler, the aerogel composition preferably comprises 4 to 15 wt. % aerogel, more preferably 5 to 12 wt. % aerogel, even more preferably 6 to 10 wt. % aerogel, based on the total weight of the aerogel composition; preferably 0.1 to 10 wt. % melamine-formaldehyde resin, more preferably 0.5 to 8 wt. % aerogel melamine-formaldehyde resin, even more preferably 1 to 7 wt. % melamine-formaldehyde resin, based on the total weight of the aerogel composition; and the remainder preferably organic solvent, optionally water, inorganic opacifying agent, and mineral filler.

[0098] When an inorganic opacifying agent and / or mineral filler is contained, the total content of the aerogel powder, melamine-formaldehyde resin, organic solvent, and optional water in the aerogel composition is typically 50% by weight or more, preferably 75% by weight or more, and more preferably 85% by weight or more. Furthermore, the total content of the inorganic opacifying agent and mineral filler in the aerogel composition is typically 50% by weight or less, preferably 25% by weight or less, and more preferably 15% by weight or less, based on the total weight of the aerogel composition.

[0099] Composite articles obtainable by the method The present invention further relates to a composite article obtainable by the method of the present invention. It is understood that the composite article exhibits the properties resulting from the method of the present invention. Accordingly, any of the characteristics described herein with respect to the method of the present invention, including any preferred ranges, also apply with respect to the composite article of the present invention.

[0100] For example, the composite article preferably contains 15 to 70 wt. % aerogel based on the total weight of the composite article, more preferably 20 to 60 wt. % aerogel, and even more preferably 30 to 50 wt. % aerogel based on the total weight of the composite article.

[0101] The composite article preferably comprises 0.1 to 20 wt. % melamine resin, more preferably 0.5 to 15 wt. %, even more preferably 1 to 12 wt. %, and even more preferably 3 to 10 wt. % aerogel, based on the total weight of the composite article.

[0102] The thickness of the composite article is preferably in the range of 0.1 mm to 500 mm. Generally, it is preferred that the composite article has a thickness of 1 to 30 mm.

[0103] It should be understood that the composite article of the present invention may contain known fillers without any particular limitation. However, the composite article preferably contains less than 15 wt. % of organic compounds other than melamine resin, and preferably contains less than 10 wt. % of binders other than melamine resin. The composite article preferably exhibits a total weight loss of less than 35 wt. % (preferably not considering the melamine resin) in a thermogravimetric analysis (TGA) when heated in a nitrogen atmosphere from 30° C. to 1100° C. at a temperature ramp rate of 10° C. / min.

[0104] Preferably, at least 50% of the fibers in the composite article have a length of 5 mm or greater. More preferably, the weight ratio of the one or more aerogels to the one or more fibers in the composite article (aerogel / fibers) is 1:8 or greater. As will be appreciated, the composite article may further comprise an inorganic opacifying agent and / or a mineral filler, as defined herein.

[0105] A composite article may be further defined by referring to either its method of manufacture or its properties.

[0106] Thus, the composite article of the present invention may be defined as comprising aerogel particles, melamine resin, and fibers, wherein the fibers are one or more selected from ceramic fibers, glass fibers, and melamine fibers, and the composite article can be obtained by injecting an aerogel composition comprising aerogel powder, melamine resin, and an organic solvent, and optionally an inorganic opacifying agent and / or a mineral filler, into a fibrous material comprising the fibers, and partially or completely removing the organic solvent to obtain the composite article.

[0107] Additionally or alternatively, the composite article comprises aerogel particles, a melamine resin, and fibers, wherein the fibers are one or more selected from ceramic fibers, glass fibers, and melamine fibers, and satisfies the following requirements (i) to (vii): (i) The composite article comprises less than 15 wt. % of organic compounds, based on the total weight of the composite article. The content of organic compounds is preferably less than 10 wt. %, more preferably less than 2 wt. %, and even more preferably less than 5 wt. In this context, the term organic compounds relates to any compound containing at least one carbon-hydrogen bond, with the exception of melamine resins. (ii) At least 50% of the fibers in the composite article have a length of 5 mm or greater. Preferably, at least 50% of the fibers in the composite article have a length of 10 mm or greater. More preferably, at least 75% of the fibers in the composite article have a length of 5 mm or greater. Even more preferably, at least 75% of the fibers in the composite article have a length of 10 mm or greater. Even more preferably, at least 75% of the fibers in the composite article have a length of 15 mm or greater. Most preferably, at least 75% of the fibers in the composite article have a length of 20 mm or greater. (iii) The composite article comprises less than 10 wt. % of a binder other than a melamine resin, based on the total weight of the composite article. The content of the binder other than a melamine resin in the composite article comprises less than 10 wt. % of the binder, preferably less than 5 wt. % of the binder, more preferably less than 2 wt. % of the binder, even more preferably less than 1 wt. % of the binder, even more preferably less than 0.5 wt. % of the binder, and most preferably less than 0.1 wt. % of the binder. (iv) The composite article exhibits a total weight loss in thermogravimetric analysis (TGA) of less than 35 wt. % when heated in a nitrogen atmosphere from 30° C. to 1100° C. at a heating rate of 10° C. / min. The total weight loss in the thermogravimetric analysis is preferably less than 30 wt. %, more preferably less than 25 wt. %, even more preferably less than 20 wt. %, even more preferably less than 15 wt. %, and most preferably less than 10 wt. %, based on the weight of the composite article prior to the thermogravimetric analysis. (v) The weight ratio of the one or more aerogels to the one or more fibers (aerogel / fibers) in the composite article is 1:8 or greater. Preferably, the weight ratio of the one or more aerogels to the one or more fibers (aerogel / fibers) in the composite article is greater than 1:8, preferably 1:4 or greater, more preferably 1:2 or greater, and even more preferably 1:1 or greater. (vi) The composite article has a burn-through time of 60 minutes or more. Preferably, the composite article has a burn-through time of 60 minutes or more, preferably 120 minutes or more, more preferably 180 minutes or more, and even more preferably 240 minutes or more. Burn-through resistance is determined using the composite article in the form of a 30 cm x 30 cm sheet 13 mm thick and treating the center of a first major surface of the composite article with a flame using a soldering torch having a temperature of 1400°C, the burn-through time being the time from the start of the flame treatment until the center of the second major surface reaches a temperature of 1000°C. (vii) When the composite article is used in the form of a 20 cm x 50 cm sheet of 13 mm thickness and is treated over the entire surface of its first major side for 180 minutes according to the ISO 834 temperature-time curve (ISO 834-8:2002 test, T = T + 345 log 10(8t + 1); where T is 20°C), the center of the second major side has a temperature of less than 1000°C. Preferably, the center of the second major side has a temperature of less than 900°C, preferably less than 800°C, more preferably less than 700°C, even more preferably less than 600°C, and even more preferably less than 500°C. It can be defined as satisfying one or more of the following:

[0108] In the case of composite articles containing melamine fibers, features (iv), (vi) and (vii) preferably do not apply. In the case of composite articles containing glass fibers, features (vi) and (vii) preferably do not apply.

[0109] The composite article may satisfy one or any number of possible combinations of requirements (i) to (vii). For example, the composite article preferably satisfies requirement (i), or requirement (ii), or requirement (iii), or requirement (iv), or requirement (v), or requirement (vi), or requirement (vii). Alternatively, it is preferred to satisfy two requirements, such as (i) and (ii), (ii) and (iii), (iii) and (iv), (iv) and (v), (v) and (vi), (vi) and (vii), (i) and (iii), (ii) and (iv), (iii) and (v), (iv) and (vi), (v) and (vii), (i) and (iv), (ii) and (v), (iii) and (vi), (iv) and (vii), (i) and (v), (ii) and (vi), (iii) and (vii), (i) and (v), (ii) and (vi), (iii) and (vii), (i) and (vii), (ii) and (vii), (ii) and (vii), (iii) and (vii), (i) and (vii).Alternatively, for example, (i) and (ii) and (iii), (i) and (ii) and (iv), (i) and (ii) and (v), (i) and (ii) and (vi), (i) and (ii) and (vii), (i) and (iii) and (iv), (i) and (iii) and (v), (i) and (iii) and (vi), (i) and (iii) and (vii), (i) and (iv) and (v), (i) and (iv) and (vi), (i) and (iv) and (vii), (i) and (v) and (vi), (i) and (v) and (vii), (i) and (v) and (vii), (i) and (v) and (vii), (i) and (vii) and (vii), (ii) and (iii) and (iv), (ii) and (iii) and (v), (ii) and (iii) and (vi), (ii) and (iii) and (vii), (ii) and Preferably, three of the requirements are met, such as (iii) and (vii), (ii) and (iv) and (v), (ii) and (iv) and (vi), (ii) and (iv) and (vii), (ii) and (v) and (vi), (ii) and (v) and (vii), (ii) and (v) and (vii), (ii) and (vi) and (vii), (iii) and (iv) and (v), (iii) and (iv) and (vi), (iii) and (iv) and (vii), (iii) and (v) and (vi), (iii) and (v) and (vii), (iii) and (vi) and (vii), (iii) and (vi) and (vii), (iv) and (v) and (vi), (iv) and (v) and (vii), (iv) and (v) and (vii), or (v) and (vii) and (vii). Alternatively, four, five, or six of the requirements are met.

[0110] It should be understood that composite articles according to these alternative definitions may also further comprise inorganic opacifying agents and / or mineral fillers. The composite article preferably comprises 15-70 wt. % aerogel, based on the total weight of the composite article. More preferred is 20-60 wt. % aerogel, and even more preferred is 30-50 wt. % aerogel, based on the total weight of the composite article.

[0111] The composite article preferably comprises 0.1 to 20 wt. % melamine resin, more preferably 0.5 to 15 wt. %, even more preferably 1 to 12 wt. %, and even more preferably 3 to 10 wt. % aerogel, based on the total weight of the composite article.

[0112] The composite article preferably has a thickness in the range of 3 mm to 500 mm, preferably in the range of 3 mm to 100 mm, more preferably in the range of 3 mm to 50 mm, and even more preferably in the range of 5 mm to 30 mm (for example, in the case of fiberboard). Alternatively, the composite article preferably has a thickness in the range of 0.1 mm to 30 mm, preferably in the range of 0.5 to 10 mm, more preferably in the range of 1 to 3 mm, and even more preferably in the range of 1 to less than 3 mm (which may also be called fiber paper). In general, it is preferable that the composite article has a thickness of 1 to 30 mm. In addition, if the width of the composite article is W, the length of the composite article is L, and the thickness of the composite article is T, the following requirements must be met:

number

[0113] It is understood that the composite articles of the present invention may include additional components, such as, for example, inert fillers or pigments, flame retardants, fire and smoke suppressants, binders, etc., which are preferably added by inclusion in the aerogel composition.

[0114] The composite articles of the present invention may further be coated with a variety of other materials and / or combined with other materials such as, for example, woven fabrics and laminates to form further composites.

[0115] The present invention can be summarized by the following items:

[0116] 1. A method for preparing a composite article comprising aerogel particles, a melamine resin, and fibers, wherein the fibers are one or more selected from ceramic fibers, glass fibers, and melamine fibers; Providing a fibrous material comprising fibers, the fibers being one or more selected from ceramic fibers, glass fibers, and melamine fibers; providing an aerogel composition comprising an aerogel powder, a melamine-formaldehyde resin, and an organic solvent; combining the fibers with an aerogel composition; Partially or completely removing the organic solvent to obtain a composite article. The method comprising:

[0117] 2. The method for preparing a composite article according to item 1, wherein the composite article further comprises an inorganic opacifying agent and / or a mineral filler, and the step of providing an aerogel composition comprising an aerogel powder, a melamine-formaldehyde resin, and an organic solvent comprises providing an aerogel composition comprising an aerogel powder, a melamine-formaldehyde resin, an organic solvent, and an inorganic opacifying agent and / or a mineral filler.

[0118] 3. The method for preparing a composite article according to item 1 or 2, wherein the fibrous material is selected from batting, nonwoven fabric, mat, felt and needled fiber blanket, and the fibrous material is preferably a nonwoven fiber blanket or a needled fiber blanket.

[0119] 4. Fibrous material: 20-300 kg / m 3 , preferably 50 to 200 kg / m 3 , more preferably 80 to 150 kg / m 3 4. The method for preparing a composite article according to any one of items 1 to 3, wherein the composite article has a density of

[0120] 5. A method for preparing a composite article according to any one of the preceding items, wherein the ceramic fibers comprise 80% by weight or more of alumina, preferably 85% by weight or more of alumina, preferably 90% by weight or more of alumina, preferably 95% by weight or more of alumina, based on the total weight of the ceramic fibers, and the alumina content is preferably 99% by weight or less, more preferably 98% by weight or less, and even more preferably 97% by weight or more, based on the total weight of the ceramic fibers.

[0121] 6. The method for preparing a composite article according to item 5, wherein the ceramic fibers further comprise 0 to 20 wt% silica, preferably 1 to 20 wt% silica, more preferably 1 to 15 wt% silica, even more preferably 1 to 10 wt% silica, and even more preferably 2 to 6 wt% silica, based on the total weight of the ceramic fibers.

[0122] 7. The method for preparing a composite article according to item 5, wherein the ceramic fibers contain less than 2 wt. % of components other than silica and alumina, preferably less than 1 wt. % of components other than silica and alumina, and more preferably less than 0.5 wt. % of components other than silica and alumina, based on the total weight of the ceramic fibers.

[0123] 8. The method for preparing a composite article according to any one of items 1 to 4, wherein the ceramic fibers comprise 2 to less than 80 wt. % alumina, preferably 15 to less than 80 wt. % alumina, more preferably 20 to 75 wt. % alumina, based on the total weight of the ceramic fibers.

[0124] 9. The method for preparing a composite article according to item 8, wherein the ceramic fibers further comprise 10 to 98 wt. % silica, preferably 15 to 90 wt. % silica, more preferably 20 to 85 wt. % silica, and even more preferably 25 to 80 wt. % silica, based on the total weight of the ceramic fibers.

[0125] 10. The method for preparing a composite article according to item 8 or 9, wherein the ceramic fibers comprise 30 to 35 wt. % alumina, 50 to 55 wt. % silica, and 4 to 20 wt. % of the sum of ZrO2, Fe2O3, TiO2, MgO, and CaO, based on the total weight of the ceramic fibers.

[0126] 11. The method for preparing a composite article according to item 8 or 9, wherein the ceramic fibers comprise 42 to 48 wt. % alumina and 52 to 58 wt. % silica, based on the total weight of the ceramic fibers.

[0127] 12. The method for preparing a composite article according to item 8 or 9, wherein the ceramic fibers comprise 28 to 32 wt. % alumina, 52 to 56 wt. % silica, and 14 to 18 wt. % ZrO2, based on the total weight of the ceramic fibers.

[0128] 13. A method for preparing a composite article according to item 8 or 9, wherein the ceramic fibers comprise 22 to 34 wt. % alumina and 66 to 78 wt. % silica, based on the total weight of the ceramic fibers.

[0129] 14. A method for preparing a composite article according to item 8 or 9, wherein the ceramic fibers comprise 66 to 78 wt. % alumina and 22 to 34 wt. % silica, based on the total weight of the ceramic fibers.

[0130] 15. A method for preparing a composite article according to any one of items 1 to 4, wherein the ceramic fibers contain less than 2 wt. % alumina, preferably less than 1 wt. % alumina, more preferably less than 0.5 wt. % alumina, based on the total weight of the ceramic fibers.

[0131] 16. The method for preparing a composite article according to item 15, wherein the ceramic fibers further comprise 50 to 85 wt. % silica and 15 to 50 wt. % alkaline earth metal oxide, preferably 55 to 85 wt. % silica and 15 to 45 wt. % alkaline earth metal oxide, more preferably 60 to 82 wt. % silica and 18 to 40 wt. % alkaline earth metal oxide, based on the total weight of the ceramic fibers.

[0132] 17. The method for preparing a composite article according to item 15, wherein the ceramic fibers further comprise 55 to 72 wt. % silica and 28 to 45 wt. % alkaline earth metal oxide, preferably 60 to 70 wt. % silica and 30 to 40 wt. % alkaline earth metal oxide, based on the total weight of the ceramic fibers.

[0133] 18. The method for preparing a composite article according to item 15, wherein the ceramic fibers further comprise 65 to 85 wt. % silica and 15 to 35 wt. % alkaline earth metal oxide, preferably 70 to 80 wt. % silica and 20 to 30 wt. % alkaline earth metal oxide, based on the total weight of the ceramic fibers.

[0134] 19. The method for preparing a composite article according to any one of items 16 to 18, wherein the alkaline earth metal oxide is selected from MgO and CaO or a combination thereof, and the content of CaO in the alkaline earth metal oxide is preferably 75% by weight or more, more preferably 85% by weight or more, based on the total amount of the alkaline earth metal oxide.

[0135] 20. The method for preparing a composite article according to any one of items 8 to 14 and items 16 to 19, wherein the content of components other than those specified in each item of the ceramic fiber is less than 2% by weight, preferably less than 1% by weight, and more preferably less than 0.5% by weight, based on the total weight of the ceramic fiber.

[0136] 21. A method for preparing a composite article according to any one of items 1 to 20, wherein the glass fibers comprise a total of 50 to 60% by weight of SiO2, 10 to 18% by weight of AI2O3, 0 to 8% by weight of MgO, 12 to 28% by weight of CaO, 2 to 15% by weight of B2O3, and 0 to 3% by weight of alkali metal oxides, and preferably a total of 52 to 56% by weight of SiO2, 12 to 16% by weight of AI2O3, 0 to 6% by weight of MgO, 15 to 25% by weight of CaO, 4 to 13% by weight of B2O3, and 0 to 3% by weight of alkali metal oxides.

[0137] 22. A method for preparing a composite article according to any one of items 1 to 20, wherein the melamine fibres comprise at least 50% by weight, preferably 60% by weight, more preferably 70% by weight, even more preferably 80% by weight, even more preferably 90% by weight, or even more preferably 95 or 98% by weight of polymer units derived from the reaction of melamine with formaldehyde.

[0138] 23. A method for preparing a composite article according to any one of items 1 to 22, wherein the melamine fibers comprise 99% or more by weight of melamine resin.

[0139] 24. A method for preparing a composite article according to any one of items 1 to 23, wherein at least 50% by weight of the fibers are ceramic fibers, preferably at least 60% by weight, more preferably at least 70% by weight, even more preferably at least 80% by weight, even more preferably at least 90% by weight, even more preferably at least 95% by weight, even more preferably at least 98% by weight, and even more preferably all.

[0140] 25. The method for preparing a composite article according to any one of items 1 to 24, wherein 50% by weight or more of the fibers are glass fibers, preferably 60% by weight or more, more preferably 70% by weight or more, even more preferably 80% by weight or more, even more preferably 90% by weight or more, even more preferably 95% by weight or more, even more preferably 98% by weight or more, and even more preferably all.

[0141] 26. The method for preparing a composite article according to any one of items 1 to 25, wherein 50% by weight or more of the fibers are melamine fibers, preferably 60% by weight or more, more preferably 70% by weight or more, even more preferably 80% by weight or more, even more preferably 90% by weight or more, even more preferably 95% by weight or more, even more preferably 98% by weight or more, and even more preferably all of the fibers are melamine fibers.

[0142] 27. A method for preparing a composite article according to any one of items 1 to 23, wherein the fibers comprise ceramic fibers and, optionally, glass fibers and / or melamine fibers; preferably, at least 50% by weight of the fibers are ceramic fibers, the remainder being glass fibers and / or melamine fibers.

[0143] 28. The organic solvent is a hydrocarbon solvent, preferably C 3-16 selected from saturated, unsaturated or partially saturated hydrocarbons or mixtures thereof, more preferably C 3-10 selected from saturated linear or branched or cyclic hydrocarbons or mixtures thereof, more preferably C 3-10 selected from linear or branched alkanes or mixtures thereof, more preferably C 5-7 3. A method for preparing a composite article according to any one of the preceding items, wherein the alkane is selected from a linear or branched alkane or a mixture thereof, even more preferably selected from hexane or heptane or a mixture thereof, and most preferably n-hexane.

[0144] 29. The organic solvent is an alcohol solvent, preferably C 2-12 is selected from saturated, unsaturated or partially saturated alcohols or mixtures thereof, more preferably C 2-12 is selected from saturated linear, branched or cyclic alcohols or mixtures thereof, more preferably C 2-12 is selected from saturated linear, branched or cyclic monohydric alcohols or mixtures thereof, and even more preferably C 2-6 28. The process for preparing a composite article according to any one of items 1 to 27, wherein the alcohol is selected from saturated linear, branched or cyclic monohydric alcohols or mixtures thereof, even more preferably propanol or mixtures thereof, most preferably 2-propanol.

[0145] 30. A method for preparing a composite article according to any one of the preceding items, wherein the aerogel comprises or consists of one or more selected from silicon oxide, aluminum oxide, zirconium oxide, titanium oxide, hafnium oxide and yttrium oxide, preferably the aerogel comprises or consists of silicon oxide, more preferably the aerogel is a silica aerogel.

[0146] 31. A method for preparing a composite article according to any one of the preceding items, wherein the aerogel has a porosity of 85% or more, more preferably 90% or more, as determined by isothermal adsorption and desorption.

[0147] 32. When the aerogel is determined according to DIN ISO 9277 2003-05 (Determination of the specific surface area of ​​solids by gas adsorption according to the BET method), the specific surface area is 300 m 2 / g or more, preferably 400m 2 / g or more, preferably 500m 2 / g or more, preferably 600m 2 / g or more, and preferably 2000m 2 / g or less, more preferably 1500m 2 / g or less, and even more preferably 1000m 2 A method for preparing a composite article according to any one of the preceding items, having a specific surface area of ​​0.15 wt. sq. / g or less.

[0148] 33. A method for preparing a composite article according to any one of the preceding items, wherein the aerogel powder has a median particle size (d50) in the range of 1 to 50 μm, preferably 5 to 40 μm, more preferably 10 to 30 μm, and even more preferably 15 to 25 μm, as measured by laser diffraction, preferably using a Malvern Mastersizer.

[0149] 34. A method for preparing a composite article according to any one of the preceding items, wherein the aerogel powder is obtained from a heterophase reaction.

[0150] 35. A method for preparing a composite article according to any one of the preceding items, wherein the aerogel powder is silica aerogel powder obtained by mixing and reacting deionized water, water glass, an organosilane compound, an inorganic acid, and an organic solvent, preferably by mixing and reacting a nonpolar organic solvent to obtain silica hydrogel primary particles, subjecting these silica hydrogel primary particles to solvent substitution, and drying the gel particles after solvent substitution under normal pressure to obtain silica aerogel powder, preferably without grinding or sieving treatment.

[0151] 36. A method for preparing a composite article according to any one of items 1 or 3 to 35, wherein the aerogel composition is a dispersion of aerogel powder and melamine-formaldehyde resin in an organic solvent.

[0152] 37. A method for preparing a composite article according to any one of items 1 and 3 to 36, wherein the aerogel composition contains 2 to 20 wt % aerogel, preferably 4 to 15 wt % aerogel, more preferably 5 to 12 wt % aerogel, even more preferably 6 to 10 wt % aerogel, and 0.1 to 20 wt % aerogel-formaldehyde resin, based on the total weight of the aerogel composition; preferably 0.1 to 10 wt % melamine-formaldehyde resin, more preferably 0.5 to 8 wt % aerogel melamine-formaldehyde resin, even more preferably 1 to 7 wt % melamine-formaldehyde resin, based on the total weight of the aerogel composition; and the remainder is preferably an organic solvent.

[0153] 38. A method for preparing a composite article according to any one of items 1 and 3 to 37, wherein the total content of the aerogel powder, melamine-formaldehyde resin, and organic solvent in the aerogel composition is 90% by weight or more, preferably 95% by weight or more, more preferably 97% by weight or more, even more preferably 98% by weight or more, still more preferably 99% by weight or more, most preferably 99.5% by weight or more, and even more preferably 99.8% by weight or more.

[0154] 39. A method for preparing a composite article according to any one of items 2 to 35, wherein the aerogel composition is a dispersion of aerogel powder, melamine-formaldehyde resin, inorganic opacifying agent and / or mineral filler in an organic solvent.

[0155] 40. The method for preparing a composite article according to any one of items 2 to 35 and 39, wherein the inorganic opacifying agent comprises or consists of one or more selected from iron oxide, zirconium oxide, titanium oxide, silicon carbide and graphite, preferably the inorganic opacifying agent comprises or consists of one or more selected from iron oxide, zirconium oxide and silicon carbide, more preferably the inorganic opacifying agent is iron oxide or silicon carbide.

[0156] 41. A method for preparing a composite article according to any one of items 2 to 35, 39 and 40, wherein the mineral filler comprises or consists of one or more selected from metal hydroxides and hydrated carbonates, preferably the mineral filler comprises or consists of one or more selected from aluminum hydroxide, magnesium hydroxide, hydromagnesite and hydrocalcite, more preferably the mineral filler is one or both selected from magnesium dihydroxide and aluminum trihydroxide.

[0157] 42. The method for preparing a composite article according to any one of items 2 to 35 and 39 to 41, wherein the aerogel composition comprises 2 to 20 wt. % aerogel, preferably 4 to 15 wt. % aerogel, more preferably 5 to 12 wt. % aerogel, even more preferably 6 to 10 wt. % aerogel, and 0.1 to 20 wt. % melamine-formaldehyde resin, based on the total weight of the aerogel composition, and preferably 0.1 to 10 wt. % melamine-formaldehyde resin, more preferably 0.5 to 8 wt. % aerogel melamine-formaldehyde resin, even more preferably 1 to 7 wt. % melamine-formaldehyde resin, with the remainder preferably being organic solvent, inorganic opacifying agent, and mineral filler.

[0158] 43. The method for preparing a composite article according to any one of items 2 to 35 and 39 to 42, wherein the total content of the aerogel powder, melamine-formaldehyde resin, and organic solvent in the aerogel composition is 50% by weight or more, preferably 75% by weight or more, and more preferably 85% by weight or more.

[0159] 44. A method for preparing a composite article according to any one of items 2 to 35 and 39 to 43, wherein the total content of the inorganic opacifying agent and the mineral filler in the aerogel composition is 50% by weight or less, preferably 25% by weight or less, and more preferably 15% by weight or less.

[0160] 45. A method for preparing a composite article according to any one of the preceding items, wherein the fibrous material and the aerogel composition are combined by injecting, impregnating, or soaking the fibrous material with the aerogel composition.

[0161] 46. ​​A method for preparing a composite article according to any one of the preceding items, wherein partially or completely removing the organic solvent by drying to obtain the composite article comprises drying at a temperature between 50°C and 170°C for 1 hour to 8 hours, optionally followed by drying at a temperature between 171°C and 230°C for 1 hour to 48 hours.

[0162] 47. A method for preparing a composite article according to any one of the preceding items, wherein the composite article comprises 15 to 70 wt %, preferably 20 to 60 wt %, more preferably 30 to 50 wt % aerogel, based on the total weight of the composite article, and 0.1 to 20 wt %, preferably 0.5 to 15 wt %, more preferably 1 to 12 wt %, even more preferably 3 to 10 wt % melamine resin, based on the total weight of the composite article.

[0163] 48. A method for preparing a composite article according to any one of the preceding items, wherein the composite article has a thickness in the range of 0.1 mm to 500 mm, preferably 1 to 30 mm.

[0164] 49. If the width of the composite article is W, the length of the composite article is L, and the thickness of the composite article is T, then:

number

[0165] 50. A method for preparing a composite article according to any one of the preceding paragraphs, wherein the composite article comprises less than 15% by weight of organic compounds, preferably less than 10% by weight of organic compounds, more preferably less than 5% by weight of organic compounds, the term organic compounds relating to any compound containing at least one carbon-hydrogen bond, excluding melamine resins.

[0166] 51. A method for preparing a composite article according to any one of the preceding items, wherein at least 50% of the fibers in the composite article have a length of 5 mm or greater, preferably at least 50% of the fibers in the composite article have a length of 10 mm or greater, more preferably at least 75% of the fibers in the composite article have a length of 5 mm or greater, even more preferably at least 75% of the fibers in the composite article have a length of 10 mm or greater, even more preferably at least 75% of the fibers in the composite article have a length of 15 mm or greater, and most preferably at least 75% of the fibers in the composite article have a length of 20 mm or greater.

[0167] 52. A method for preparing a composite article according to any one of the preceding items, wherein the composite article comprises less than 10% by weight of binders other than melamine resins, preferably less than 5% by weight of binders other than melamine resins, more preferably less than 2% by weight of binders other than melamine resins, even more preferably less than 1% by weight of binders other than melamine resins, even more preferably less than 0.5% by weight of binders other than melamine resins, and most preferably less than 0.1% by weight of binders other than melamine resins.

[0168] 53. A method for preparing a composite article according to any one of the preceding items, wherein the composite article exhibits a total weight loss in thermogravimetric analysis (TGA) of less than 35 wt%, preferably less than 30 wt%, more preferably less than 25 wt%, even more preferably less than 20 wt%, even more preferably less than 15 wt%, and most preferably less than 10 wt%, when heated in a nitrogen atmosphere from 30°C to 1100°C at a heating rate of 10°C / min.

[0169] 54. A method for preparing a composite article according to any one of the preceding items, wherein the weight ratio of the one or more aerogels to the one or more fibers in the composite article (aerogel / fibers) is 1:8 or greater, preferably 1:4 or greater, more preferably 1:2 or greater, and even more preferably 1:1 or greater.

[0170] 55. A composite article obtainable by a method according to any one of the preceding paragraphs.

[0171] 56. A composite article comprising aerogel particles, a melamine resin and fibers, wherein the fibers are one or more selected from ceramic fibers, glass fibers and melamine fibers, and the composite article can be obtained by injecting, impregnating or immersing a fibrous material comprising the fibers with an aerogel composition comprising aerogel powder, a melamine-formaldehyde resin and an organic solvent, and optionally an inorganic opacifying agent and / or a mineral filler, and then partially or completely removing the organic solvent to obtain the composite article.

[0172] 57. A composite article comprising aerogel particles, melamine resin, and fibers, wherein the fibers are one or more selected from ceramic fibers, glass fibers, and melamine fibers, and meets the following requirements (i) to (vii): (i) The composite article contains less than 15% by weight of organic compounds other than melamine resin; (ii) at least 50% of the fibers in the composite article have a length of 5 mm or greater; (iii) the composite article contains less than 10% by weight of a binder other than a melamine resin; (iv) the composite exhibits a total weight loss of less than 35 wt.% in thermogravimetric analysis (TGA) when heated in a nitrogen atmosphere from 30°C to 1100°C at a heating rate of 10°C / min; (v) the weight ratio of the one or more aerogels to the one or more fibers in the composite article (aerogel / fibers) is 1:8 or greater; (vi) the composite article has a burn-through time of 60 minutes or more, the burn-through resistance being determined by using the composite article in the form of a 30 cm x 30 cm sheet 13 mm thick and treating the composite article at the center of its first major surface with a flame using a soldering torch having a temperature of 1400°C, the burn-through time being the time from the start of the flame treatment until the center of the second major surface reaches a temperature of 1000°C; (vii) when the composite article is used in the form of a 20 cm x 50 cm sheet having a thickness of 13 mm and is treated across its first major surface for 180 minutes according to the temperature-time curve of ISO 834, the center of the second major surface has a temperature of less than 1000°C; A composite article that satisfies one or more of the above.

[0173] 58. The composite article of item 57, further comprising an inorganic opacifying agent and / or a mineral filler.

[0174] 59. A composite article according to item 57 or 58, wherein the composite article comprises less than 15% by weight of organic compounds, preferably less than 10% by weight of organic compounds, more preferably less than 5% by weight of organic compounds, the term organic compounds relating to any compound containing at least one carbon-hydrogen bond, with the exception of melamine resins.

[0175] 60. The composite article according to any one of items 57 to 59, wherein at least 50% of the fibers in the composite article have a length of 5 mm or more, preferably at least 50% of the fibers in the composite article have a length of 10 mm or more, more preferably at least 75% of the fibers in the composite article have a length of 5 mm or more, even more preferably at least 75% of the fibers in the composite article have a length of 10 mm or more, even more preferably at least 75% of the fibers in the composite article have a length of 15 mm or more, and most preferably at least 75% of the fibers in the composite article have a length of 20 mm or more.

[0176] 61. The composite article according to any one of items 57 to 60, wherein the composite article comprises less than 10% by weight of binders other than melamine resins, preferably less than 5% by weight of binders other than melamine resins, more preferably less than 2% by weight of binders other than melamine resins, even more preferably less than 1% by weight of binders other than melamine resins, even more preferably less than 0.5% by weight of binders other than melamine resins, and most preferably less than 0.1% by weight of binders other than melamine resins.

[0177] 62. The composite article of any one of items 57 to 61, wherein the composite article exhibits a total weight loss in thermogravimetric analysis (TGA) of less than 35 wt%, preferably less than 30 wt%, more preferably less than 25 wt%, even more preferably less than 20 wt%, even more preferably less than 15 wt%, and most preferably less than 10 wt%, when heated in a nitrogen atmosphere from 30°C to 1100°C at a heating rate of 10°C / min.

[0178] 63. The composite article according to any one of items 57 to 62, wherein the weight ratio of the one or more aerogels to the one or more fibers (aerogel / fibers) in the composite article is higher than 1:8, preferably 1:4 or higher, more preferably 1:2 or higher, and even more preferably 1:1 or higher.

[0179] 64. The composite article according to any one of items 57 to 63, wherein the composite article comprises 15 to 70 wt. %, preferably 20 to 60 wt. %, more preferably 30 to 50 wt. % aerogel, based on the total weight of the composite article, and 0.1 to 20 wt. %, preferably 0.5 to 15 wt. %, more preferably 1 to 12 wt. %, even more preferably 3 to 10 wt. % melamine resin, based on the total weight of the composite article.

[0180] 65. The composite article according to any one of items 57 to 64, wherein the composite article has a thickness in the range of 1 mm to 500 mm, preferably in the range of 1 mm to 30 mm.

[0181] 66. The composite article according to any one of items 57 to 65, wherein the composite article has a burn-through time of 60 minutes or more, preferably 120 minutes or more, more preferably 180 minutes or more, and even more preferably 240 minutes or more.

[0182] 67. The composite article of any one of items 57 to 66, wherein when the composite article is used in the form of a 20 cm x 50 cm sheet of 13 mm thickness and is treated over the entire surface of its first major surface for 180 minutes according to the ISO 834 temperature-time curve, the centre of the second major surface has a temperature of less than 900°C, preferably less than 800°C, more preferably less than 700°C, even more preferably less than 600°C, and even more preferably less than 500°C.

[0183] 68. If the width of the composite article is W, the length of the composite article is L, and the thickness of the composite article is T, then the following requirements apply:

number

[0184] Example 1 material Aerogel powder (JIOS AeroVa aerogel powder, D20 grade) 2-Propanol (Technical Grade) Ceramic fiber paper (Uniflax Insulflax paper containing 55-72% by weight of silica and 28-45% by weight of alkaline earth metal oxides) with a base paper thickness of 1 mm, paper density 150 kg / m 3 ). Melamine fiber blanket with a thickness of 18 mm (Smart Melamine Doo's meltblown melamine nonwoven blanket, containing over 99% melamine resin) Original blanket: 3.5mm thick ceramic fiber blanket (Frenzelitt's Isotame S Breeze, containing over 94% SiO2) Original blanket: 8mm thick ceramic fiber blanket (Frenzelitt's Isotame S Breeze, containing over 94% SiO2) Melamine-formaldehyde resin (MER-Resin 1.0 HS, Smart Melamine Doo) Deionized water (DI water) Carbon Black N550 A soldering torch (Rothenberger Industrial, Typrophia Piezo 1950, 35429) equipped with a gas cartridge (Rothenberger Industrial, 30% propane / 70% butane)

[0185] experiment 1. Preparation of blend dispersions containing aerogel powder and melamine-formaldehyde resin The aerogel was dispersed in 2-propanol to a solids content of 11 wt % using standard laboratory mixing equipment, specifically a propeller mixer (Heidl overhead stirrer RZR2020). A 14 wt % solids melamine-formaldehyde resin solution in 2-propanol / DI-water (2:1 wt ratio) was prepared using the same equipment. Blend dispersions containing aerogel powder and melamine-formaldehyde resin were prepared by mixing the aerogel dispersion and melamine-formaldehyde resin solution in various ratios, as shown in Table 1.

[0186] [Table 1]

[0187] The resulting blend dispersion remained homogeneous without agglomeration of the aerogel particles or coagulation of the melamine-formaldehyde resin, as shown in FIG.

[0188] 2. Incorporation of the blend dispersion into a substrate The blend dispersions were successfully incorporated into various substrates by impregnation: - Melamine fiber blanket (Figures 2 and 3) - Ceramic fiber blanket (Figures 4 and 5) - Ceramic fiber paper (Figure 6) The parameters for impregnation of the blend dispersions are summarized in Table 2:

[0189] [Table 2]

[0190] Representative preparation of aerogel-embedded melamine fiber blanket: Blend Dispersion 3 (aerogel:melamine-formaldehyde resin = 7:1) was impregnated into a melamine fiber blanket at room temperature by immersing the base blanket in the blend dispersion. The resulting prototype was immediately dried in a hot air oven at 150 °C for 4 hours after impregnation. Note that the impregnated melamine fiber blanket was dried either without pressure or under pressure, as shown in Figure 2. The blanket dried under pressure exhibits a more uniform blanket morphology as well as a more sealed surface, as shown in Figure 3.

[0191] Similar to the melamine fiber blankets, ceramic fiber blankets of various thicknesses were also impregnated with Blend Dispersion 3. As shown in Figures 4 and 5, the impregnated ceramic fiber blankets dried under pressure exhibited homogeneous blanket morphology and surface.

[0192] It should be noted that the impregnated 8 mm thick ceramic fiber blankets were dried / cured using two different approaches: i) dried / cured under pressure at 150 °C in a hot air oven; ii) dried under pressure at 110 °C in a hot air oven followed by curing under various pressures at 150 °C in a hot press.

[0193] The blend dispersion was also impregnated into a very thin substrate, 1 mm thick ceramic fiber paper, as shown in Figure 6. The structure-reinforced aerogel-embedded ceramic fiber paper has a very homogeneous and well-sealed surface.

[0194] The structurally reinforced aerogel-embedded melamine fiber blanket was further reinforced by applying a melamine-formaldehyde resin to its surface. As shown in Figure 7, the resulting coated prototype of Example 8 exhibits a more sealed surface compared to the uncoated blanket.

[0195] Results and Evaluation 1.Structural Enhancement and Fire Resistance of Aerogel-Incorporated Materials To investigate the thermal insulation performance and high temperature resistance, a 3.5 mm thick structurally reinforced aerogel-embedded ceramic fiber blanket (Example 10) was exposed to the flame of a soldering torch, as shown in Figure 8. The soldering torch had a flame temperature of approximately 1350°C. The temperature rise on the backside (unexposed side) of the blanket was recorded with a thermocouple.

[0196] The structurally reinforced aerogel-embedded ceramic fiber blanket exhibited high resistance to torch flames. As shown in Figure 9, the blanket withstood torch firing at 1350°C for 60 minutes without burn-through or cracking. The discoloration of the flame "halo" was due to the decomposition of the melamine resin and the evaporation of decomposition by-products.

[0197] The thermal insulation performance of the structurally reinforced aerogel-embedded ceramic fiber blanket was also confirmed, with the maximum temperature of the unexposed surface measured not exceeding 480°C over the entire 60-minute test period.

[0198] The results of the soldering torch test confirm that structural reinforcement by means of applying melamine resin as a binder does not deteriorate the thermal insulation performance and resistance to extreme high temperatures of the aerogel-embedded inorganic fiber material.

[0199] 2. Dust release behavior of structurally reinforced aerogel-embedded materials An additional technical advantage of structural reinforcement by applying melamine resin as a binder in aerogel-incorporated materials is the improved adhesion between the aerogel particles and the fiber matrix, and therefore, low dust emissions from the aerogel-incorporated materials can be expected.

[0200] An 11.6 mm thick structurally reinforced aerogel-embedded melamine fiber blanket (Example 6) was tested for dust emission behavior under harsh conditions. The blanket was shaken, bent, and punctured on a steel plate. As shown in Figure 10, almost no coarse particles were observed on the steel plate and were no longer suspended in the air. This confirms that structural reinforcement by applying melamine resin as a binder can significantly reduce dust emission from aerogel-embedded materials.

[0201] 3. Structural Enhancement of Aerogel-Incorporated Materials and Their Thermal Conductivity A comparison of the thermal conductivity of an unfilled, unreinforced aerogel-embedded ceramic fiber blanket and a structurally reinforced aerogel-embedded ceramic fiber blanket (Example 9) at 0, 10, 20, and 40°C is given in Figure 11. It can be seen that the incorporation of aerogel particles significantly reduces the thermal conductivity of the blanket. Reinforcement by applying melamine resin as a binder results in only a slight increase in thermal conductivity, e.g., an increase of 1 mW / m K at 0°C.

[0202] 4. Structural Enhancement of Aerogel-Incorporated Materials' Compressive Strength An additional technical benefit of structural reinforcement by applying melamine resin as a binder to aerogel-incorporated materials is the improvement of the material integrity of the composite, thereby improving the mechanical strength of the aerogel-incorporated material.

[0203] Compression tests were performed on a 3.5 mm-thick unreinforced aerogel-embedded ceramic fiber blanket and a structurally reinforced aerogel-embedded ceramic fiber blanket (Example 9) using a materials testing machine (Gardavini Quasar 5). The blanket specimens were compressed to 80% of their original thickness. As shown in Figure 12, at the same 80% compressive strain, the structurally reinforced aerogel-embedded ceramic fiber blanket exhibited a compressive stress of 1.6 MPa, while the unreinforced aerogel-embedded ceramic fiber blanket exhibited a compressive stress of 0.6 MPa. This confirms that structural reinforcement using melamine resin as a binder can significantly improve the mechanical strength of aerogel-embedded materials.

[0204] 5. Thermal Decomposition Behavior of Structure-reinforced Aerogel-incorporated Materials Thermogravimetric analysis (TGA) was performed to compare the aerogel-incorporated ceramic fiber blanket (aerogel level 51%) with the structurally reinforced sample (aerogel level 36%, resin level 5%, Example 9). The TGA analysis temperature range was set to 23-1100°C, and the analysis atmospheres were nitrogen (23-600°C) and synthetic air (600-1100°C), respectively.

[0205] The two blanket specimens exhibited similar weight loss curves recorded by TGA, as shown in Figure 13. The rest masses of the unreinforced aerogel-embedded ceramic fiber blanket and the structurally reinforced ceramic fiber blanket were measured to be 87.98% and 86.86%, respectively. Two additional decomposition transitions were observed for the reinforced aerogel-embedded ceramic fiber blanket: At i) 200-230°C and ii) 400-450°C, a weight loss of 1.9% higher than that of the unreinforced sample was measured.

[0206] The TGA results confirm that structural reinforcement by applying melamine resin as a binder at a certain level (e.g., 5%) has a negligible effect on the thermal degradation behavior of the aerogel-incorporated materials.

[0207] Description of the method used for testing 1 Thermogravimetric analysis (TGA) TGA was performed using a NETZSCH TG209 F1 Libra device. The analytical temperature range was 23°C to 1100°C. TGA was performed in pure nitrogen (23°C to 600°C) and synthetic air (600°C to 1100°C). Weight loss was recorded throughout the analysis.

[0208] 2. Fire resistance test To investigate the fire resistance, a soldering torch test was performed. Test specimens were cut to dimensions of 30 x 30 cm and exposed to a soldering torch (Rothenberger Industrial, Type Rofia Piezo 1950, 35429) equipped with a gas cartridge (Rothenberger Industrial, 30% propane / 70% butane). The flame temperature of this gas cartridge ranged from 1300 to 1400 °C. A thermocouple (Type K) was placed in the center of the back side of the test specimen (the side not exposed to the flame) and the temperature rise was recorded.

[0209] 3. Thermal conductivity Thermal conductivity was measured according to the DIN EN 12667 standard by using the heat flow meter method with a LaserComp Fox 200 instrument. Test specimens were cut to dimensions of 20x20cm and their thermal conductivities at 0, 10, 20 and 40°C were recorded as results.

[0210] 4. Compression test Compression tests were performed according to ASTM D 1056 standard by using a Galdavini testing apparatus. Test specimens were cut into cylindrical samples with a diameter of 29 mm. Once the specified preload was reached, the initial height of the sample was measured. The sample was compressed to 80% of its initial height at a rate of 20 mm / min. The sample was then decompressed to reach 0.1 N. Four more compression cycles were repeated on the same sample. The compressive stress and strain were recorded.

Claims

1. 1. A method for preparing a composite article comprising aerogel particles, a melamine resin, and fibers, comprising: the fibers are one or more selected from ceramic fibers, glass fibers, and melamine fibers; providing a fibrous material comprising fibers, wherein the fibers are one or more selected from ceramic fibers, glass fibers, and melamine fibers; providing an aerogel composition comprising an aerogel powder, a melamine-formaldehyde resin, and an organic solvent; combining the fibrous material and the aerogel composition; partially or completely removing said organic solvent to obtain said composite article. The method comprising:

2. 10. The method for preparing a composite article according to claim 1, wherein the ceramic fibers comprise at least 80 weight percent alumina and the ceramic fibers comprise less than 2 weight percent of components other than silica and alumina, based on the total weight of the ceramic fibers.

3. 10. The method for preparing a composite article according to claim 1, wherein the ceramic fibers comprise from 2 to less than 80 weight percent alumina and from 10 to 98 weight percent silica, based on the total weight of the ceramic fibers.

4. 10. The method for preparing a composite article according to claim 1, wherein the ceramic fibers contain less than 2% by weight alumina, 50-85% by weight silica, and 15-50% by weight alkaline earth metal oxides.

5. The method for preparing a composite article according to claim 1 or 2, wherein the organic solvent is an alcohol solvent.

6. 3. The method for preparing a composite article according to claim 1 or 2, wherein the aerogel is a silica aerogel.

7. 3. The method for preparing a composite article according to claim 1 or 2, wherein the aerogel has a porosity of 85% or greater as determined by isothermal adsorption and desorption.

8. The aerogel has a specific surface area of ​​300 m2 determined according to DIN ISO 9277 2003-05 (determination of the specific surface area of ​​solids by gas adsorption using the BET method). ２ 3. A method for preparing a composite article according to claim 1 or 2, wherein the composite article has a specific surface area of ​​1 / g or more.

9. 3. The method for preparing a composite article according to claim 1 or 2, wherein the aerogel composition is a dispersion of the aerogel powder, a melamine-formaldehyde resin, and the melamine-formaldehyde resin in the organic solvent, and the total content of the aerogel powder, the melamine-formaldehyde resin, and the organic solvent in the aerogel composition is 90 wt % or more based on the total weight of the aerogel composition.

10. 3. The method for preparing a composite article according to claim 1 or 2, wherein the fibrous material and the aerogel composition are combined by injecting, impregnating or soaking the fibrous material with the aerogel composition.

11. 3. The method for preparing a composite article according to claim 1 or 2, wherein the composite article comprises 15 to 70 wt % aerogel and 0.1 to 20 wt % melamine resin, based on the total weight of the composite article.

12. 3. The method for preparing a composite article according to claim 1 or 2, wherein at least 50% of the fibers in the composite article have a length of 10 mm or greater.

13. 3. The method for preparing a composite article according to claim 1 or 2, wherein the weight ratio of the one or more aerogels to the one or more fibers (aerogel / fibers) in the composite article is 1:4 or greater.

14. 1. A composite article comprising aerogel particles, a melamine resin, and fibers, The fibers are one or more selected from ceramic fibers, glass fibers, and melamine fibers, and satisfy the following requirements (i) to (vii): (i) the composite article contains less than 15% by weight of organic compounds other than the melamine resin; (ii) at least 50% of the fibers in the composite article have a length of 5 mm or greater; (iii) the composite article comprises less than 10% by weight of a binder other than the melamine resin; (iv) the composite article exhibits a total weight loss of less than 35 wt. % in thermogravimetric analysis (TGA) when heated in a nitrogen atmosphere from 30° C. to 1100° C. at a temperature increase of 10° C. / min; (v) the weight ratio of the one or more aerogels to the one or more fibers (aerogel / fibers) in the composite article is 1:8 or greater; (vi) the composite article has a burn-through time of 60 minutes or greater, the burn-through resistance being determined by using the composite article in the form of a 30 cm x 30 cm sheet having a thickness of 13 mm and treating the composite article at the center of its first major surface with a flame using a soldering torch having a temperature of 1400°C, the burn-through time being the time from the start of flame treatment until the center of the second major surface reaches a temperature of 1000°C; (vii) when the composite article is used in the form of a 20 cm x 50 cm sheet of 13 mm thickness and is treated over the entire surface of its first major surface for 180 minutes according to the temperature-time curve of ISO 834, the center of the second major surface has a temperature of less than 1000°C. A composite article in which one or more of the above conditions are met.

15. A composite article obtainable by the method according to any one of claims 1 to 13.

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