Composite article comprising aerogel particles and foam

Abstract

The present invention relates to a method for preparing a composite article comprising aerogel particles and a foam and a composite article obtainable by the method.

Description

[0001] The present invention relates to a method for preparing a composite article comprising aerogel particles and a foam, and to a composite article obtainable by this method.

[0002] In many industrial and building applications, there is a need for thermal insulation capabilities and heat resistance at high temperatures. In view of the prior art, the present invention aims to provide a foam with improved thermal insulation capabilities and heat resistance at a reduced cost.

[0003] The inventors have surprisingly found that this problem can be solved by incorporating the aerogel into the foam after the foam has been formed. This can be achieved by preparing an aerogel composition comprising aerogel powder and an organic solvent and impregnating, soaking or injecting it into the foam.

[0004] Due to several problems, it is very difficult to incorporate aerogels into the substrate of the foam. First, in reactive foaming (such as PUR foam, melamine foam, phenolic foam, etc.), the very high surface area of the aerogel particles leads to a sharp increase in the viscosity of the reaction system. Therefore, an aerogel loading level of more than 10 wt% does not allow a reliable foaming process. In addition, in thermoplastic foaming, the aerogel particles cause significant nucleation during the foaming process. Therefore, when aerogel particles are incorporated into the substrate for the foam before foaming, an aerogel loading level comparable to that in the present invention cannot be achieved in the prior art.

[0005] Accordingly, in a first aspect, the present invention relates to a method for preparing a composite article comprising aerogel particles and a foam, the method comprising:

[0006] - providing a foam-containing article comprising a foam,

[0007] - providing an aerogel composition comprising aerogel powder and an organic solvent (A),

[0008] - combining the foam-containing article with the aerogel composition, and

[0009] - partially or completely removing the organic solvent (A) to obtain the composite article.

[0010] Furthermore, the present invention relates to a composite article obtainable by this method.

[0011] In addition, the present invention relates to a composite article comprising aerogel particles and a foam, wherein the composite article is obtainable by impregnating, soaking or injecting an aerogel composition comprising aerogel powder and an organic solvent (A) and optionally an inorganic light-shielding agent and / or a mineral filler into a foam-containing article comprising a foam, and partially or completely removing the organic solvent (A) to obtain the composite article.

[0012] In yet another aspect, the present invention relates to a composite article comprising aerogel particles and foam, wherein one or more of the following requirements (i)-(v) are met:

[0013] (i) The weight ratio of one or more aerogels to one or more foams (aerogel / foam) in the composite article is 1:8 or higher;

[0014] (ii) The thermal conductivity of the composite article at 0 °C is not higher than 0.030 W / m·K. Preferably, the thermal conductivity at 0 °C is not higher than 0.028 W / m·K, more preferably not higher than 0.026 W / m·K, even more preferably not higher than 0.024 W / m·K, still more preferably not higher than 0.022 W / m·K;

[0015] (iii) The thermal conductivity of the composite article at 20 °C is not higher than 0.032 W / m·K. Preferably, the thermal conductivity at 20 °C is not higher than 0.030 W / m·K, more preferably not higher than 0.028 W / m·K, even more preferably not higher than 0.026 W / m·K, still more preferably not higher than 0.024 W / m·K;

[0016] (iv) The thermal conductivity of the composite article at 40 °C is not higher than 0.034 W / m·K. Preferably, the thermal conductivity at 40 °C is not higher than 0.032 W / m·K, more preferably not higher than 0.030 W / m·K, even more preferably not higher than 0.028 W / m·K, still more preferably not higher than 0.026 W / m·K.

[0017] (v) The burn-through time of the composite article is 10 minutes or longer, wherein the burn-through resistance is determined as follows: using the composite article in the form of a 16 cm x 16 cm sheet with a thickness of 8 mm, and treating the composite article at the center of its first major surface by using a propane gas burner (a flame source defined in DIN EN ISO 11925-2, flammability of products subjected to direct impingement of flame - Part 2: Single-flame source test), wherein the burn-through time is the duration from the start of the flame treatment until the flame reaches the center of the second major surface.

[0018] The thermal conductivity referred to herein is preferably measured according to standard DIN EN 12667 by using the heat flow meter method with a LaserComp Fox200 device and a sample having a size of 20 x 20 cm.

[0019] Brief Description of the Drawings

[0020] Figure 1 : Thermal conductivity values of Comparative Example 1 and Examples 1-3

[0021] Figure 2 : Photographs of Examples 2, 4, and 5

[0022] Figure 3 : The filled foam shows surprisingly high flexibility ( Figure 3 b), with little difference from the unfilled foam used as a reference ( Figure 3 a) (Example 4).

[0023] Figure 4 : No significant dust emission was observed when bending the filled foam sample: The micrographs of Example 2 show a high degree of filling and aerogel agglomeration behavior compared to the unfilled reference ( Figure 4 a). Figure 4 b).

[0024] Figure 5 : Photos of Example 2 taken after exposure to direct flame. Flame penetration in the filled foam is significantly hindered, and no burn-through occurs even after 10 minutes of direct exposure:

[0025] Figure 5 a and 5c: Unfilled foam (Comparative Example 1): Burn-through after exposure to direct flame (5a: burning side; 5c: unexposed side).

[0026] Figure 5 b and 5d: Filled foam (Example 2): No burn-through even after 10 minutes (5b: burning side; 5d: unexposed side).

[0027] Definitions of terms used herein

[0028] In the context of the present invention, the term "composite article" should be understood to mean any article comprising one or more aerogel particles and one or more foams. Thus, the term "composite" does not imply any limitation other than the presence of aerogel particles and foams, which together form a foam-containing article. It should be understood that the aerogel particles and the foam are not far apart in space. More precisely, the aerogel particles are typically located inside the foam.

[0029] Composite articles are generally in the form of foam sheets, tubes or any other molded shape. The thickness of the composite article is preferably in the range of 3 mm to 500 mm, more preferably in the range of 3 mm to 100 mm, even more preferably in the range of 3 mm to 50 mm, and even more preferably in the range of 5 mm to 30 mm. The extension in the other two dimensions is preferably at least 5 times the thickness each. It should be understood that the term "dimension" as used herein refers to the three known spatial dimensions orthogonal to each other (as understood in "three-dimensional").

[0030] As used herein, the term "sheet" generally refers to a foam-containing article that extends in one dimension less than the other two dimensions. Preferably, it refers to a foam-containing article that extends in one dimension by at most 1000 mm, preferably at most 500 mm, more preferably at most 100 mm, and extends at least five times in each of the other two dimensions. In other words, the term "sheet" generally refers to a flat or rectangular article.

[0031] Unless otherwise clearly defined, the use of the singular or plural form shall be understood to permit the presence of "one or more" nouns in the singular or plural form. In particular, the term "foam-containing article" means "an article containing one or more foams". Similarly, the term "aerogel composition containing aerogel powder and organic solvent" should be understood to also include cases where more than one (type) of aerogel powder and / or more than one (type) of organic solvent are contained in the aerogel composition. Mixtures of different types of aerogel powders and / or mixtures of different types of organic solvents can be used.

[0032] As used herein, the term "melamine-formaldehyde resin" or "melamine-formaldehyde binder" refers to an oligomer (or mixture of oligomers) obtained mainly (usually at least 50% by weight) from melamine and formaldehyde, where formaldehyde acts as a crosslinking agent. Melamine usually reacts with formaldehyde under alkaline conditions to form a mixture of various oligomers, also known as hydroxymethyl melamine. 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, still more preferably 90% by weight, or even 95 or 98% by weight of atoms obtained from the reaction of melamine and formaldehyde. Such oligomers can further condense upon additional heating or readily react with thiol, hydroxyl, carboxyl, and amide groups to form a three-dimensional thermosetting polymer network. Due to its oligomeric nature, it is soluble in water or a mixture of water and an organic solvent (i.e., at 20 °C in a mixture of water and 2-propanol in a weight ratio of 1:1, the solubility is preferably higher than 5 g / l). In differential scanning calorimetry (DSC), an exothermic enthalpy in the temperature range of 100 - 200 °C is usually observable in the DSC thermogram of "melamine-formaldehyde resin" or "melamine-formaldehyde binder" (preferably, the enthalpy integral in this range is 10 J·g -1 or greater). "Melamine-formaldehyde resin" or "melamine-formaldehyde binder" is generally used in the production method of the present invention, and the final product usually contains its crosslinked product, which is referred to herein as "melamine resin" or "crosslinked melamine-formaldehyde resin".

[0033] As used herein, the term "melamine resin" or "crosslinked melamine-formaldehyde resin" refers to a polymer obtainable by crosslinking a "melamine-formaldehyde resin" or a "melamine-formaldehyde binder". Crosslinking may also be referred to as "curing" and generally refers to heating to a temperature of at least 100 °C, typically heating to a temperature of 120 - 180 °C for 1 - 8 hours. Thus, "melamine resin" or "crosslinked melamine-formaldehyde resin" preferably relates to a polymer containing at least 50 wt%, preferably 60 wt%, more preferably 70 wt%, even more preferably 80 wt%, still more preferably 90 wt% or even 95 or 98 wt% of atoms resulting from the reaction of melamine and formaldehyde. "Melamine resin" or "crosslinked melamine-formaldehyde resin" is generally a crosslinked material and is insoluble in water or a mixture of water and an organic solvent (i.e., at 20 °C in a mixture of water and 2-propanol in a weight ratio of 1:1, the solubility is preferably less than 5 g / l). Due to the crosslinked nature, the exothermic enthalpy in the temperature range of 100 - 200 °C is generally not visible in the DSC thermogram of "melamine resin" or "crosslinked melamine-formaldehyde resin" (preferably, the enthalpy integral in this range is not higher than 10 J·g -1 ). The definition of "melamine resin" also applies to melamine in melamine foam.

[0034] 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 replaced by a gas, with substantially no collapse of the gel structure. Preferably, the "aerogel" is a silica aerogel. Such silica aerogel generally has a density of 0.1 g / cm 3 or less, preferably 0.05 g / cm 3 or less, and can be prepared by well-known methods. In the present invention, the "aerogel" is preferably a silica aerogel, which can be obtained according to the method described in EP 2 722 311 A2, preferably as defined in its claim 22.

[0035] In the present invention, the term "aerogel particles" preferably refers to silica aerogel particles that can be obtained according to the method described in EP 2 722 311 A2, preferably as defined in its claim 22. Aerogel particles suitable for the present invention are commercially available, for example, as "Jios AeroVa", where preferably the "D20 grade" is used. "Jios AeroVa D20 grade" is described as having a D95 particle size range of less than 20 μm, a bulk density of 0.03 - 0.1 g / cm 3 , a thermal conductivity of 0.017 - 0.022 W / m·k, a surface area of 600 - 800 m 2 / g, and a porosity of greater than 90%.

[0036] The term "heterogeneous reaction" preferably refers to any reaction that takes place in a system comprising more than one phase, for example in a system comprising two immiscible phases, namely an aqueous phase and a phase immiscible with the aqueous phase (preferably a non-polar solvent phase). The reaction (i.e., the establishment of the first structure) starts at the interface between the different phases. Accordingly, it does not cover reactions in which all reactants are dissolved in the same solvent. Examples of "heterogeneous reactions" are emulsification reactions, suspension reactions or dispersion reactions.

[0037] The term "foam-containing article" refers to any article comprising one or more foams. Thus, examples include foam sheets, tubes or any other molded articles. The thickness of the foam-containing article is preferably in the range from 3 mm to 500 mm, more preferably in the range from 3 - 100 mm, even more preferably in the range from 3 - 50 mm, and most preferably in the range from 5 - 30 mm, while extending at least 5 times in the other two dimensions. Preferably, the "foam-containing article" is a foam.

[0038] The term "aerogel composition" as used herein relates to any mixture comprising an aerogel powder and an organic solvent. Preferably, the "aerogel composition" is a mixture comprising an aerogel powder dispersed in an organic solvent. In other words, the "aerogel composition" is preferably an "aerogel dispersion".

[0039] 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 liquid material. The terms solid and liquid as used herein refer to the state of the material at a temperature of 25 °C and a pressure of 1 atm. To be "dispersed" preferably describes a situation in which the particles do not readily sediment in the continuous phase of the liquid.

[0040] The term "organic solvent" as used herein refers to any organic compound that is liquid at a temperature of 20 °C and a pressure of 1 atm. Preferred examples of organic solvents include hydrocarbon solvents and alcohols, including any mixtures thereof. Hydrocarbons are to be understood as organic compounds consisting of carbon and hydrogen atoms.

[0041] It should be understood that the term "removing the organic solvent" preferably also includes removing water and may additionally include curing (usually crosslinking) of the melamine-formaldehyde resin.

[0042] 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 products of the present invention, foam materials and any melamine-formaldehyde resins are preferably not considered as organic compounds.

[0043] Terms such as "comprises" or "contains" in phrases like "A comprises B" are used herein to express an open definition of a composition or the like. Thus, "A comprises B" should be understood to indicate that A contains at least B, but may additionally contain any number and amount of other components. In contrast, the term "consists of" in phrases like "A consists of B" generally means that A does not contain components other than B.

[0044] Terms such as "preferably" indicate that a certain feature may or may not be achieved. Thus, such terms are superior to optional features. Generally, if the feature is achieved, additional beneficial effects are expected to be produced.

[0045] As used herein, the term "injecting" refers to the act of introducing (usually with the application of force) a fluid (such as an aerogel composition) into a solid material (such as a foam-containing article). Suitable methods for "injecting" are described, for example, in EP 3 023 528A1.

[0046] As used herein, the terms "impregnating" or "soaking" refer to the act of introducing (usually without force) a fluid (such as an aerogel composition) into a solid porous material (such as a foam). "Impregnating" or "soaking" can be achieved, for example, by placing the foam-containing article to be impregnated or soaked in a container that contains the typical liquid material for impregnating the article, or by pouring the liquid onto the article to be impregnated or soaked.

[0047] As used herein, the term "adhesive" refers to any material intended to provide an adhesive force between two solid materials. Preferably, the term "adhesive" refers to any material used to bond aerogel particles to each other and / or to a foam. The adhesive can have an organic or inorganic nature. Specific examples of adhesives include, but are not limited to, water glass, polysiloxane-based adhesives, and phenolic resin-based adhesives.

[0048] Detailed Description of the Invention

[0049] The present invention relates to a method for preparing a composite article comprising aerogel particles and a foam, and to a composite article obtainable by this method.

[0050] Method

[0051] The present invention relates to a method for preparing a composite article comprising aerogel particles and a foam, the method comprising:

[0052] - providing a foam-containing article comprising a foam,

[0053] - providing an aerogel composition comprising aerogel powder and an organic solvent (A),

[0054] - combining the foam-containing article with the aerogel composition, and

[0055] - Partially or completely removing the organic solvent (A) to obtain the composite article.

[0056] The method is not limited to these steps and may include any number of additional steps before, between, and after each of these steps. Thus, the above steps are not necessarily consecutive steps. However, preferably they are carried out in the specified order. Furthermore, preferably these steps are consecutive.

[0057] Each of the steps of the method described herein may include additional activities. For example, the step of providing an aerogel composition comprising aerogel powder and an organic solvent (A) may include providing an aerogel composition containing additional components in addition to the aerogel powder and the organic solvent (A). Furthermore, the step of combining the foam-containing article and the aerogel composition may include not only combining the foam-containing article and the aerogel composition, but also combining other articles, compositions, etc.

[0058] Preferably, the foam-containing article and the aerogel composition are combined by injecting, soaking, or impregnating the aerogel composition into the foam-containing article, more preferably by impregnating or soaking the aerogel composition into the foam-containing article. Suitable methods for injecting such a composition are known to those skilled in the art and are described, for example, in EP 3 023 528 A1.

[0059] Preferably, obtaining the composite article by drying to partially or completely remove the organic solvent (A) includes drying at a temperature of 50 - 150 °C for 1 - 8 hours, preferably drying at a temperature of 100 °C to 120 °C for 1 - 48 hours.

[0060] Composite article to be obtained by this method

[0061] The composite article obtainable by the method of the present invention preferably contains 50 - 98% by weight of aerogel based on the total weight of the composite article. Based on the total weight of the composite article, more preferably 60 - 96% by weight, still more preferably 70 - 95% by weight, or even 75 - 95% by weight, 80 - 95% by weight, or 85 - 95% by weight, such as 88 - 92% by weight of aerogel.

[0062] The thickness of the composite article is generally in the range of 3 mm to 500 mm, preferably in the range of 3 - 100 mm, more preferably in the range of 3 - 50 mm, and even more preferably in the range of 5 - 30 mm.

[0063] When 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 satisfies the following requirements:

[0064]

[0065] wherein R is 100 or greater, preferably 1000 or greater, more preferably 10000 or greater,

[0066] wherein W / L is preferably in the range of 1000 / 1 - 1 / 1000,

[0067] wherein W / T is preferably 10 or greater, and

[0068] wherein L / T is preferably 10 or greater.

[0069] The composite article may further comprise an inorganic light-shielding agent and / or a mineral filler. Thus, the step of preferably providing an aerogel composition comprising an aerogel powder and an organic solvent (A) is the step of providing an aerogel composition comprising an aerogel powder and an organic solvent (A) and an inorganic light-shielding agent and / or a mineral filler.

[0070] Foam

[0071] The foam used in the method of the present invention is generally a foam in which at least half (i.e., 50% or more) of the pores are interconnected. This continuous interconnected capillary network allows liquids and gases to move through the open or porous pore structure. The open-cell ratio of the foam is preferably 60 - 99%, particularly 85 - 95% or 90 - 99%. According to ASTM D2856, the foam preferably has an open-cell content of 40 - 99%. The foam preferably comprises one or more selected from the group consisting of polyurethane (PUR) foam, polyisocyanurate (PIR) foam, melamine foam, phenolic foam, chemically crosslinked polyolefin foam, polypropylene foam, and mixtures thereof. Among them, melamine foam is particularly preferred.

[0072] Polyurethane (PUR) foam

[0073] Flexible polyurethane (PUR) foams are specifically disclosed in WO 1996 / 001867 A1. Thus, such flexible open-cell polyurethane foams can be prepared as the reaction product of a mixture comprising (a) aliphatic, cycloaliphatic, araliphatic and / or aromatic polyisocyanates and (b) a polyol component. Component (a) is usually MDI or polymeric MDI. As the polyol component, any compound having more than one, preferably more than two, hydroxyl groups can be used. Examples include ethylene glycol, propylene glycol, 1,4-butanediol or 1,6-hexanediol. In addition, the polyol can be a polyether polyol, a polyester polyol and / or a polyamide polyol. Polyester polyols for polyurethanes can be prepared by the condensation reaction between a diol (such as ethylene glycol, propylene glycol, 1,4-butanediol or 1,6-hexanediol) and a dicarboxylic acid. Polyol components having 4-8 hydroxyl groups include erythritol, pentaerythritol; pentites such as arabitol, adonitol or xylitol; hexites, such as sorbitol, mannitol or dulcitol. Low molecular weight reaction products of polyhydroxy compounds such as those described above with ethylene oxide and / or propylene oxide can be used particularly well, and low molecular weight reaction products of other compounds containing groups capable of reacting with ethylene oxide and / or propylene oxide can also be used, such as polyamines, such as ammonia, ethylenediamine, 1,4-diaminobenzene, 2,4-diaminotoluene, 2,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 1-methyl-3,5-diethyl-2,4-diaminobenzene and / or 1-methyl-3,5-diethyl-2,6-diaminobenzene. Other suitable polyamines are described in EP-A-0 265 781.

[0074] Suitable crosslinking agents include triethanolamine and the reaction products of aldehydes or ketones with polyamines (such as ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), pentaethylenehexamine (PEHA), hexaethyleneheptamine, propylenediamine, dipropylenetriamine, tripropylenetetramine, tetrapropylenepentamine, pentapropylenehexamine or hexapropyleneheptamine).

[0075] Polyisocyanurate (PIR) foams

[0076] Polyisocyanurate (PIR) foams are described, for example, in WO 2020 / 142887 A1. Similar to polyurethane (PUR) foams, PIR is usually obtained by the reaction of isocyanate (MDI) and polyol. While for PUR, the components MDI and polyol are used in a molar ratio of about 1.00, in the production of PIR, MDI is used in a molar excess (such as 1.01:1 or more, 1.03:1 or more, 1.05:1 or more, 1.10:1 or more or even 1.2:1 or more). The polyol and crosslinking agent can be as described above for polyurethane foams.

[0077] Melamine foam

[0078] Melamine foam is a polymer obtained by reacting melamine (2,4,6-triamino-1,3,5-triazine) with one or more aldehydes. The aldehyde is usually one or more selected from formaldehyde, acetaldehyde, trimethylolacetaldehyde, acrolein, benzaldehyde, furfural, glyoxal, phthalaldehyde and terephthalaldehyde; and preferably contains at least 50% by weight of formaldehyde, more preferably the aldehyde is formaldehyde. Therefore, the preferred melamine foam is a foam containing a polymer obtained by reacting melamine (2,4,6-triamino-1,3,5-triazine) with formaldehyde. Melamine foams described in, for example, US 4,334,971 and DE 10 2010 009588 A1 can be used. Thus, the elastic open-cell melamine-formaldehyde resin foam can be prepared, for example, as described in EP-A 071 672 or EP-A037 470. The molar ratio of melamine to aldehyde (e.g., formaldehyde) is usually less than 1:1, and preferably between 1:1 and 1:5, especially between 1:1.5 and 1:3.5.

[0079] Melamine-formaldehyde precondensates can be used to prepare melamine foams. Besides melamine, such melamine-formaldehyde precondensates usually contain up to 50% by weight, preferably up to 20% by weight, of other thermosetting resin precursors as co-condensation units, and besides formaldehyde, can contain up to 50% by weight, preferably up to 20% by weight, of other aldehydes as co-condensation units, but unmodified melamine-formaldehyde condensates are particularly preferred. Examples of additional thermosetting resin precursors that can be present are alkyl-substituted melamines, urea, urethanes, carboxamides, dicyandiamide, guanidine, thioamides, sulfonamides, aliphatic amines, phenols and their derivatives. Examples of other aldehydes that can be used are acetaldehyde, trimethylolacetaldehyde, acrolein, benzaldehyde, furfural, glyoxal, phthalaldehyde and terephthalaldehyde. Further details on melamine-formaldehyde condensates can be found in Houben-Weyl, Methoden der organischen Chemie, Volume 14 / 2, 1963, pages 319 - 402. The molar ratio of thermosetting resin precursor:aldehyde can vary within a wide range, i.e., 1:1.5 - 1:5; in the case of melamine-formaldehyde condensates, it is preferably 1:2.5 - 1:3.5. Melamine resins advantageously contain co-condensed sulfite groups; these can be introduced, for example, by adding 1 - 20% by weight of sodium bisulfite during or after resin condensation. The sulfite groups make the resin more hydrophilic and thus more compatible with water. In addition, a higher degree of condensation can be achieved thereby. Using such a melamine-formaldehyde precondensate, the desired foam can then be prepared, for example, by foaming an aqueous or alcoholic (e.g., ethanol) solution or dispersion containing the melamine-formaldehyde precondensate, an emulsifier, a foaming agent and a hardener, and optionally additives, and then crosslinking the precondensate, wherein in order to effect foaming and crosslinking, the solution or dispersion is heated. The heating can be affected by ultra-high frequency radiation in such a way that the power absorbed by the solution or dispersion is 5 - 200 KW per kg of water or alcohol in the solution or dispersion.

[0080] Phenolic foam

[0081] Suitable phenolic foams can be found, for example, in WO 2007 / 029222 A1. Phenolic foams contain phenolic resins. Phenolic resins can be obtained by the reaction of phenol and / or phenolic compounds (preferred phenolic compounds are selected from cresols, xylenols, p-C 1-6 -alkylphenols, p-phenylphenol or resorcinol) with aldehydes (preferred aldehydes are formaldehyde, furfural or acetaldehyde). Typical phenolic resins include novolac resins and phenolic varnish resins.

[0082] Alkaline catalysts (such as sodium hydroxide, potassium hydroxide, calcium hydroxide, or fatty amines (such as trimethylamine or triethylamine)) are usually used in the production of resole resins. The molar ratio of phenolic groups (hydroxyl groups attached to carbon as part of an aromatic group) to aldehyde groups is not particularly limited. Especially in the case of resole resins, the molar ratio of phenolic groups to aldehyde groups is preferably in the range of 1:1 - 1:3, more preferably in the range of 1:1.5 - 1:2.5, and particularly preferably 1:1.6 - 1:2.1.

[0083] To prepare novolac resins, acid catalysts (such as benzenesulfonic acid, p-toluenesulfonic acid, xylenesulfonic acid, naphthalenesulfonic acid, ethylbenzenesulfonic acid, or phenolsulfonic acid) are usually used. Especially in the case of novolac resins, the molar ratio of phenolic groups to aldehyde groups is preferably in the range of 1:1 - 3:1, more preferably 1.05:1 - 2.5:1, and particularly preferably 1.2:1 - 1.5:1.

[0084] Phenolic resins can directly form to produce thermosetting network polymers (usually when the aldehyde groups are in excess), or they can be formed by preparing prepolymers (usually when the phenolic groups are in excess, such as in the case of novolacs). The prepolymer can then be molded and cured by adding additional formaldehyde and preferably heating.

[0085] In addition to phenolic resins, phenolic foams preferably also contain hydrocarbon blowing agents (preferably one or more hydrocarbons having 1 - 8 carbon atoms; for example, 1 - 20 parts by weight relative to 100 parts by weight of the phenolic resin), any catalyst. Optionally, inorganic fillers (such as metal hydroxides, such as aluminum hydroxide, magnesium hydroxide; metal carbonates, such as calcium carbonate, magnesium carbonate, barium carbonate, zinc carbonate; for example, 0.1 - 30 parts by weight relative to 100 parts by weight of the phenolic resin) are used to adjust the pH of the foam to avoid corrosion when the metal structure is in contact with the phenolic foam for a long time.

[0086] Chemically crosslinked polyolefin foams

[0087] Chemically crosslinked polyolefin foams are described, for example, in WO 2006 / 024658 A1. Therefore, chemically crosslinked polyolefin foams preferably contain 50 - 95 wt% of polyolefin and 5 - 50% of polystyrene. Preferred examples of chemically crosslinked polyolefin foams are chemically crosslinked PE (XLPE) foams.

[0088] The proportion of polystyrene in the chemically crosslinked polyolefin foam is preferably at most 50 wt%, but can be adjusted within a wide range. The preferred quantitative ratios of polyolefin and polystyrene are 60 wt% and 40 wt%, 70 wt% and 30 wt%, 80 wt% and 20 wt%, 90 wt% and 10 wt%, respectively.

[0089] The polyolefins used are in particular polyethylene and / or polypropylene, in each case a homopolymer, copolymer or polymer blend. Mixtures of several different polystyrenes, polyethylenes and / or polypropylenes (for example with different molecular weights or melt flow indices) can also be used.

[0090] The polymer components are used in particular without prior functionalization or compatibilization, for example by grafting with silanes or monomers such as styrene or methacrylate, etching, radiation, flame treatment or corona treatment.

[0091] Preferably, the polymer foam according to the invention does not contain any other polymers apart from the polymer components (polyolefins and polystyrene), such that the weight fractions of the above polyolefins and polystyrene together amount to 100% of all polymer components of the foam. Optionally, small proportions of 1-10% by weight of other polymers can be added, such as ethylene vinyl acetate, ethyl acetate ethylene, polyvinyl butyral, hydrogenated polystyrene and / or polybutene.

[0092] Suitable crosslinking agents can be selected from organic peroxides and / or use triallyl isocyanurate as a co-agent.

[0093] Polypropylene foam

[0094] Suitable polypropylene foams are known to those skilled in the art and are disclosed in WO 1994 / 013460 A1. Suitable propylene polymers include propylene homopolymers (polypropylene) and copolymers of propylene with copolymerizable ethylenically unsaturated comonomers. The propylene polymer foam can also contain small amounts (usually not more than 10% by weight, preferably not more than 5% by weight) of non-propylene polymers. The propylene polymer can consist of only one or more propylene homopolymers, one or more propylene copolymers, a blend of one or more of each of propylene homopolymers and copolymers. Regardless of the composition, based on the total weight of the monomer units in the propylene polymer, the propylene polymer preferably contains more than 50% by weight, more preferably at least 70% by weight of propylene monomer units.

[0095] Suitable monoethylenically unsaturated comonomers include olefins, vinyl acetate, methyl acrylate, ethyl acrylate, methyl methacrylate, acrylic acid, itaconic acid, maleic acid, maleic anhydride. The propylene copolymer preferably contains 20% by weight or less of ethylenically unsaturated comonomers.

[0096] Particularly useful propylene copolymers are copolymers of propylene with one or more non-propylene olefins. Propylene copolymers include random and block copolymers of propylene with olefins selected from ethylene, C4-C10 α-olefins, and C4-C10 dienes. Propylene copolymers also include random terpolymers of propylene with α-olefins selected from ethylene and C4-C8 α-olefins. In terpolymers having both ethylene and C4-C8 α-olefins, the ethylene content is preferably 20 wt% or less. C4-C10 α-olefins include straight-chain and / or branched C4-C10 α-olefins such as 1-butene, isobutene, 1-pentene, 3-methyl-1-butene, 1-hexene, 3,4-dimethyl-1-butene, 1-heptene, and 3-methyl-1-hexene. Examples of C4-C10 dienes include 1,3-butadiene, 1,4-pentadiene, isoprene, 1,5-hexadiene, and 2,3-dimethyl-1,3-hexadiene.

[0097] Suitable non-propylene polymers that can be incorporated into polypropylene foams include high, medium, low, and linear density polyethylene, polybutene, ethylene-acrylic acid copolymers, ethylene-vinyl acetate copolymers, ethylene-propylene rubber, styrene-butadiene rubber, ethylene-ethyl acrylate copolymers, and ionomers.

[0098] Preferred propylene polymer resins are branched and / or crosslinked polypropylene resins. Branching or crosslinking can be obtained by chemical or radiation branching (see, for example, US 4,916,198 and US 4,714,716). Suitable branching / crosslinking agents include azido- and vinyl-functional silanes, organic peroxides, and polyfunctional vinyl monomers as described in WO 1994 / 013460 A1.

[0099] The foams used in the present invention are preferably chemically and / or physically crosslinked. The degree of crosslinking as determined by the gel content according to the Flory-Stockmayer theory or ASTM D2765 is preferably 40-95%. Suitable crosslinking agents can be selected by those skilled in the art based on common general knowledge according to the polymer types described above. Additional crosslinking agents include peroxides, triallyl cyanurate, triallyl isocyanurate, phenyl maleimide, thiadiazole, fatty acid amides, hydrosilylation agents, radiation activators (for radiation or ultraviolet curing), sulfur systems, bisphenols, metal oxides, etc.

[0100] Preferred blowing agents for preparing the foams include aliphatic hydrocarbons having 1-9 carbon atoms, halogenated aliphatic hydrocarbons having 1-4 carbon atoms, and aliphatic alcohols having 1-3 carbon atoms.

[0101] Aliphatic hydrocarbons include methane, ethane, propane, n-butane, isobutane, n-pentane, isopentane, neopentane. Among halogenated hydrocarbons, fluorinated hydrocarbons are preferred. Examples of fluorinated hydrocarbons include monofluoromethane, perfluoromethane, monofluoroethane, 1,1-difluoroethane, 1,1,1-trifluoroethane, 1,1,1,2-tetrafluoroethane, pentafluoroethane, perfluoroethane, 2,2-difluoropropane, 1,1,1-trifluoropropane, perfluoropropane, perfluorobutane, perfluorocyclobutane. Examples of partially halogenated chlorohydrocarbons and chlorofluorocarbons include chloromethane, dichloromethane, chloroethane, 1,1,1-trichloroethane, 1,1-dichloro-1-fluoroethane, 1-chloro-1,1-difluoroethane, 1,1-dichloro-2,2,2-trifluoroethane, and 1-chloro-1,2,2,2-tetrafluoroethane. Aliphatic alcohols include methanol, ethanol, n-propanol, and isopropanol. A mixture of any of the above substances can be used as a blowing agent.

[0102] Suitable inorganic blowing agents include carbon dioxide, nitrogen, argon, water, air, nitrogen, and helium. Chemical blowing agents include azodicarbonamide, azobisisobutyronitrile, benzenesulfonyl hydrazide, 4,4'-oxybis(benzenesulfonyl hydrazide), p-toluenesulfonyl hydrazide, barium azodicarboxylate, N,N'-dimethyl-N,N'-dinitrosoterephthalamide, and trihydrazinotriazine. It should be understood that crosslinking agents and blowing agents, especially chemical blowing agents, can decompose and / or evaporate from the foam during the foaming process.

[0103] It should be understood that the foam can include any proportion of any type of additives commonly used in foams, such as flame retardants, inorganic fillers, plasticizers, biocides, stabilizers (heat-resistant, UV, ozone, reversion, etc.), pigments.

[0104] According to DIN EN ISO 845, the foam (should be understood as before impregnation and / or coating) preferably has a density of ≤ 200 kg / m 3 , more preferably ≤ 150 kg / m 3 . Especially for melamine foam, a density of ≤ 20 kg / m 3 , more preferably ≤ 10 kg / m 3 is preferred.

[0105] Specific examples of open-cell foams that can be used in the method of the present invention include:

[0106]

[0107] Solvent (A)

[0108] The organic solvent (A) used in the method of the present invention is usually a hydrocarbon solvent, preferably selected from C 3-16 saturated, unsaturated, or partially saturated hydrocarbons or mixtures thereof, more preferably selected from C 3-10Saturated straight-chain, branched or cyclic hydrocarbons or mixtures thereof, even more preferably selected from C 3-10 Straight-chain or branched alkanes or mixtures thereof, still more preferably selected from C 5-7 Straight-chain or branched alkanes or mixtures thereof, even more preferably selected from hexane or heptane or mixtures thereof, most preferably n-hexane.

[0109] Alternatively, the organic solvent (A) used in the present invention is an alcohol solvent, preferably selected from C 2-12 Saturated, unsaturated or partially saturated alcohols or mixtures thereof, more preferably selected from C 2-12 Saturated straight-chain, branched or cyclic alcohols or mixtures thereof, even more preferably selected from C 2-12 Saturated straight-chain, branched or cyclic monohydric alcohols or mixtures thereof, still more preferably selected from C 2-6 Saturated straight-chain, branched or cyclic monohydric alcohols (such as ethanol, 1-propanol, 2-propanol, butanol, pentanol (including cyclopentanol) or hexanol (including cyclohexanol)) or mixtures thereof, even more preferably selected from propanol or mixtures thereof, most preferably 2-propanol.

[0110] In addition, the organic solvent (A) can be a mixture of one or more of the above hydrocarbon solvents and one or more alcohol solvents.

[0111] Aerogel

[0112] The aerogel can be any inorganic aerogel. Preferably, it 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 silicon oxide or consists of silicon oxide. Even more preferably, the aerogel is a silica aerogel.

[0113] The aerogel generally has a porosity of 85% or higher, more preferably 90% or higher, as determined by isothermal adsorption and desorption. More specifically, the porosity is determined by measuring the pore volume and pore size distribution of the aerogel using the BJH (Barret-Joyner-Halenda) adsorption and desorption isotherm method.

[0114] The specific surface area of the aerogel is generally 300 m 2 / g or higher. Determined by DIN ISO 9277 2003-05 (Determination of the specific surface area of solids by gas adsorption using the BET method), it is preferably 400 m 2 / g or higher, preferably 500 m 2 / g or higher, preferably 600 m 2 / g or higher, and preferably 2000 m 2 / g or less, more preferably 1500 m 2 / g or less, even more preferably 1000 m2 / g or less, more preferably 800 m 2 / g or less.

[0115] In the present invention, preferably by laser diffraction, preferably using a Malvern Mastersizer measurement, the powder of the aerogel has a median particle size (d50) in the range of 1 - 50 μm, preferably 5 - 40 μm, more preferably 10 - 30 μm, even more preferably 15 - 25 μm.

[0116] The powder of the aerogel can be obtained, for example, by a multiphase reaction. In this case, preferably the powder of the aerogel is a silica aerogel powder, which is obtained by: mixing deionized water, water glass, an organosilane compound, an inorganic acid, and an organic solvent (preferably a non-polar organic solvent) and reacting to obtain primary silica hydrogel particles. Then the primary silica hydrogel particles are solvent-substituted, and the solvent-substituted gel particles are dried under ambient pressure to obtain the silica aerogel powder. Preferably, no further grinding or sieving treatment is carried out. Such a multiphase reaction method is known to those skilled in the art and is described, for example, in EP 2 722 311.

[0117] The aerogel powder is preferably prepared in the form of particles rather than in the form of monoliths. Therefore, preferably the aerogel powder used in the present invention has been obtained by a method that does not include grinding the aerogel material. More preferably, the aerogel powder is in the form of primary particles (optionally containing secondary particles). Therefore, no grinding or sieving treatment is required to produce the aerogel powder. In addition, preferably the aerogel powder is dried under ambient pressure, for example, at 1 atm, rather than using a supercritical drying process sometimes employed in aerogel production according to the prior art.

[0118] Aerogel composition

[0119] The aerogel composition comprises an aerogel powder and an organic solvent (A). It should be understood that the aerogel composition may include other components. To achieve an effective distribution of the aerogel powder in the foam-containing product, the aerogel composition is preferably a dispersion of the aerogel powder in the organic solvent (A).

[0120] Based on the total weight of the aerogel composition, the aerogel composition generally contains 2 - 20 wt% of the aerogel, preferably 4 - 18 wt% of the aerogel, more preferably 6 - 18 wt% of the aerogel, even more preferably 10 - 18 wt% of the aerogel, and most preferably 10 - 14 wt% of the aerogel. The remaining part is preferably the organic solvent (A).

[0121] Preferably, based on the total weight of the aerogel composition, the combined content of the aerogel powder and the organic solvent (A) 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, or even 99.8% by weight or more.

[0122] Alternatively, if the method involves the use of an inorganic light-shielding agent and / or a mineral filler, the aerogel composition is preferably a dispersion of an aerogel powder, an inorganic light-shielding agent and / or a mineral filler in the organic solvent (A). Other components may or may not be included in the aerogel composition. The inorganic light-shielding agent generally comprises or consists of one or more selected from iron oxide, zirconium oxide, titanium oxide, silicon carbide, and graphite (based on the total weight of the composite article, the content of graphite in the composite article is preferably less than 5% by weight, preferably less than 2% by weight, more preferably less than 1% by weight). Among them, iron oxide, zirconium oxide, titanium oxide, and / or silicon carbide are preferred. The inorganic light-shielding agent preferably comprises or consists of one or more selected from iron oxide, zirconium oxide, and silicon carbide, and more preferably the inorganic light-shielding agent is iron oxide or silicon carbide.

[0123] 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 hydroxide and aluminum hydroxide.

[0124] Preferably, the inorganic light-shielding agent and the mineral filler are not in the form of aerogels. Particularly preferably, according to the test of DIN EN ISO 787-11, the bulk density of the inorganic light-shielding agent and more preferably also the mineral filler is at least 0.1 g / cm 3 and / or according to the test of DIN ISO9277 2003-05 (BET method), the specific surface area of the inorganic light-shielding agent and more preferably also the mineral filler is 300 m 2 / g or less. Alternatively or in addition, preferably the inorganic light-shielding agent and more preferably the mineral filler are chemically different from the material used as the aerogel. It should be understood that any combination of the inorganic light-shielding agents and mineral fillers mentioned herein can be used.

[0125] Based on the total weight of the aerogel composition, in the presence of an inorganic opacifier and / or mineral filler, the aerogel composition preferably contains 2-20% by weight of aerogel, preferably 4-18% by weight of aerogel, more preferably 6-18% by weight of aerogel, even more preferably 10-18% by weight of aerogel, most preferably 10-14% by weight of aerogel, and the balance is preferably an organic solvent (A) and an inorganic opacifier and mineral filler.

[0126] In the presence of an inorganic opacifier and / or mineral filler, the combined content of aerogel powder and organic solvent (A) in the aerogel composition is generally 50% by weight or more, preferably 75% by weight or more, more preferably 85% by weight or more. In addition, based on the total weight of the aerogel composition, the combined content of the inorganic opacifier and mineral filler in the aerogel composition is generally 50% by weight or less, preferably 25% by weight or less, more preferably 15% by weight or less.

[0127] Aerogel composition further comprising a melamine - formaldehyde oligomer resin

[0128] The aerogel composition may also contain a melamine-formaldehyde resin. Such an aerogel composition containing a melamine-formaldehyde resin is generally referred to herein as a "melamine-aerogel composition". The organic solvent used in the melamine-aerogel composition is preferably an alcohol solvent.

[0129] The melamine-aerogel composition comprises an aerogel powder, a melamine-formaldehyde resin, and an organic solvent (A). The melamine-aerogel composition preferably further contains water. Based on the total weight of the melamine-aerogel composition, the water content in the melamine-aerogel composition is preferably in the range of 1-30% by weight, more preferably in the range of 3-22% by weight, even more preferably in the range of 5-20% by weight, still more preferably in the range of 8-18% by weight, still even more preferably in the range of 11-17% by weight. It should be understood that the melamine-aerogel composition may contain additional components. In order to achieve an effective distribution of the aerogel powder and the melamine-formaldehyde resin in the fiber product, the melamine-aerogel composition is preferably a dispersion of the aerogel powder and the melamine-formaldehyde resin in an organic solvent (A) (and optionally water). The organic solvent of the melamine-aerogel composition is preferably an alcohol solvent as defined above.

[0130] Based on the total weight of the melamine - aerogel composition, the melamine - aerogel composition usually contains 2 - 20 wt% of aerogel, preferably 4 - 15 wt% of aerogel, more preferably 5 - 12 wt% of aerogel, and even more preferably 6 - 10 wt% of aerogel. In addition, based on the total weight of the melamine - aerogel composition, the melamine - aerogel composition usually contains 0.1 - 20 wt% of melamine - formaldehyde resin, preferably 0.1 - 10 wt% of melamine - formaldehyde resin, more preferably 0.5 - 8 wt% of melamine - formaldehyde resin, and even more preferably 1 - 7 wt% of melamine - formaldehyde resin. The remaining part is preferably an organic solvent (A).

[0131] The melamine - aerogel composition is preferably obtained by mixing composition A containing aerogel and a first solvent with composition B containing melamine - formaldehyde resin and a second solvent. The first solvent preferably contains at least 90 wt% of isopropanol. The second solvent is preferably a mixture of isopropanol and water, more preferably containing 40 - 80 wt% of isopropanol and 60 - 20 wt% of water, preferably 50 - 80 wt% of isopropanol and 50 - 20 wt% of water, and more preferably 60 - 70 wt% of isopropanol and 40 - 30 wt% of water. The weight ratio of composition A to composition B is preferably in the range of 20:1 - 1:2, more preferably 15:1 - 1:1, even more preferably 10:1 - 1:1, still more preferably 7:1 - 1:1. Therefore, based on the total weight of the melamine - aerogel composition, the water content in the melamine - aerogel composition is preferably in the range of 1 - 30 wt%, more preferably in the range of 3 - 22 wt%, even more preferably in the range of 5 - 20 wt%, still more preferably in the range of 8 - 18 wt%, and still even more preferably in the range of 11 - 17 wt%.

[0132] The weight ratio of aerogel to melamine - formaldehyde resin in the melamine - aerogel composition is preferably in the range of 1:10 - 100:1, more preferably 1:5 - 50:1, even more preferably 1:2 - 20:1, still more preferably 1:2 - 10:1, and most preferably 1:1 - 8:1 or even 1:1 - 7:1. The same ratio is also preferably applicable to the composite product.

[0133] Preferably, based on the total weight of the melamine - aerogel composition, the combined content of aerogel powder, melamine - formaldehyde resin, organic solvent (A), and optionally water in the melamine - aerogel composition is 90 wt% or more, preferably 95 wt% or more, more preferably 97 wt% or more, even more preferably 98 wt% or more, still more preferably 99 wt% or more, most preferably 99.5 wt% or more, or even 99.8 wt% or more.

[0134] As an alternative, if the method involves the use of an inorganic light-shielding agent and / or a mineral filler, the melamine-aerogel composition is preferably a dispersion of an aerogel powder, a melamine-formaldehyde resin, an inorganic light-shielding agent and / or a mineral filler in an organic solvent (A). Other components may or may not be included in the melamine-aerogel composition. The inorganic light-shielding agent generally comprises or consists of one or more selected from iron oxide, zirconium oxide, titanium oxide, silicon carbide and graphite (based on the total weight of the composite article, the content of graphite in the composite article is preferably less than 5% by weight, preferably less than 2% by weight, more preferably less than 1% by weight). Among them, iron oxide, zirconium oxide, titanium oxide and / or silicon carbide are preferred. The inorganic light-shielding agent preferably comprises or consists of one or more selected from iron oxide, zirconium oxide and silicon carbide, and more preferably the inorganic light-shielding agent is iron oxide or silicon carbide.

[0135] 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 hydroxide and aluminum hydroxide.

[0136] Preferably, the inorganic light-shielding agent and the mineral filler are not in the form of aerogels. Particularly preferably, according to the test of DIN EN ISO 787-11, the bulk density of the inorganic light-shielding agent and more preferably also the mineral filler is at least 0.1 g / cm 3 and / or according to the test of DIN ISO9277 2003-05 (BET method), the specific surface area of the inorganic light-shielding agent and more preferably also the mineral filler is 300 m 2 / g or less. As an alternative or in addition, it is further preferred that the inorganic light-shielding agent and more preferably the mineral filler are chemically different from the material used as the aerogel. It should be understood that any combination of the inorganic light-shielding agent and the mineral filler mentioned herein can be used.

[0137] In the case of containing an inorganic light-shielding agent and / or a mineral filler, the melamine-aerogel composition preferably contains 4-15% by weight of aerogel, more preferably 5-12% by weight of aerogel, even more preferably 6-10% by weight of aerogel, based on the total weight of the melamine-aerogel composition, and preferably 0.1-10% by weight of melamine-formaldehyde resin, more preferably 0.5-8% by weight of aerogel melamine-formaldehyde resin, even more preferably 1-7% by weight of melamine-formaldehyde resin, based on the total weight of the melamine-aerogel composition, and the balance is preferably the organic solvent (A) and the inorganic light-shielding agent and the mineral filler.

[0138] In the case of containing an inorganic light-shielding agent and / or a mineral filler, the combined content of the aerogel powder, the melamine-formaldehyde resin, and the organic solvent (A) in the melamine-aerogel composition is usually 50% by weight or more, preferably 75% by weight or more, and more preferably 85% by weight or more. In addition, based on the total weight of the melamine-aerogel composition, the combined content of the inorganic light-shielding agent and the mineral filler in the melamine-aerogel composition is usually 50% by weight or less, preferably 25% by weight or less, and more preferably 15% by weight or less.

[0139] Based on the total weight of the composite article, the composite article obtained using the melamine-formaldehyde resin composition preferably contains 15 - 70% by weight of aerogel. Based on the total weight of the composite article, more preferably 20 - 60% by weight, and still more preferably 30 - 50% by weight of aerogel.

[0140] Based on the total weight of the composite article, the composite article obtained using the melamine-formaldehyde resin composition preferably contains 0.1 - 20% by weight of melamine resin. Based on the total weight of the composite article, more preferably 0.5 - 15% by weight, even more preferably 1 - 12% by weight, and still more preferably 3 - 10% by weight of melamine resin.

[0141] Optional coating comprising a crosslinked melamine - formaldehyde resin

[0142] The method of the present invention may further include an additional step of coating the composite article with a coating composition containing a melamine-formaldehyde resin. The composite article thus obtained may also be referred to as a coated composite article.

[0143] The step of coating the composite article with a coating composition containing a melamine-formaldehyde resin is preferably carried out by spraying the coating composition onto the composite article to be coated.

[0144] The coating composition contains a melamine-formaldehyde resin and preferably a solvent (B). The solvent (B) contains an organic solvent and water. It should be understood that the organic solvent in the solvent (B) is preferably selected to form a homogeneous mixture with the water in the solvent (B). More preferably, the organic solvent in the solvent (B) is an alcohol solvent, preferably selected from C 2-12 saturated, unsaturated or partially saturated alcohols or mixtures thereof, more preferably selected from C 2-12 saturated straight-chain, branched or cyclic alcohols or mixtures thereof, even more preferably selected from C 2-12 saturated straight-chain, branched or cyclic monohydric alcohols or mixtures thereof, still more preferably selected from C 2-6Saturated straight-chain, branched or cyclic monohydric alcohols (such as ethanol, 1-propanol, 2-propanol, butanol, pentanol (including cyclopentanol) or hexanol (including cyclohexanol)) or mixtures thereof, even more preferably selected from propanol or mixtures thereof, and most preferably 2-propanol. It should be understood that the organic solvent can be a mixture of one or more such alcohol solvents.

[0145] The solvent (B) is preferably a mixture of isopropanol and water, and more preferably contains 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.

[0146] Based on the total weight of the coating composition, the coating composition preferably contains 0.1 - 30% by weight of melamine - formaldehyde resin, preferably 1 - 25% by weight of melamine - formaldehyde resin, more preferably 3 - 22% by weight of aerogel melamine - formaldehyde resin, even more preferably 5 - 20% by weight of melamine - formaldehyde resin, still more preferably 10 - 20% by weight of melamine - formaldehyde resin, and even still more preferably 12 - 18% by weight of melamine - formaldehyde resin.

[0147] Preferably based on the total weight of the coating composition, the combined content of melamine - formaldehyde resin and solvent (B) in the coating 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, or even 99.8% by weight or more.

[0148] Optionally, the coating composition may contain an inorganic light - shielding agent and / or a mineral filler, such as those described above for the aerogel composition.

[0149] After the step of coating the composite article with the coating composition containing melamine - formaldehyde resin, there may be a step of partially or completely removing the solvent (B), which includes drying / curing at a temperature of 120 - 180 °C for 1 - 8 hours.

[0150] The coated composite article preferably contains 0.1 - 20% by weight of melamine resin based on the total weight of the coated composite article. Based on the total weight of the coated composite article, more preferably 0.5 - 18% by weight, and even more preferably 1 - 15% by weight of melamine resin.

[0151] The thickness of the coated composite article is preferably in the range of 0.1 mm to 500 mm. Generally, it is preferably that the thickness of the coated composite article is 1 - 30 mm.

[0152] The coating weight of the coated composite article is preferably at 1 g / m 2to 2000 g / m 2 in the range of, more preferably in the range of 2 g / m 2 to 1000 g / m 2 in the range of, even more preferably in the range of 5 g / m 2 to 500 g / m 2 in the range of, still more preferably in the range of 10 g / m 2 to 300 g / m 2 in the range of. As will be understood by those skilled in the art, the coating weight can be readily determined by varying the concentration of the coating composition (in particular the amount of components other than the solvent in the coating composition) and / or the amount of coating composition applied.

[0153] Composite article obtainable by this method

[0154] The present invention also relates to a composite article obtainable by the method according to the present invention. It should be understood that the composite article exhibits the properties resulting from the method of the present invention. Accordingly, any feature described herein with respect to the method of the present invention, including any preferred ranges, also applies to the composite article of the present invention.

[0155] For example, based on the total weight of the composite article, the composite article preferably contains 50 - 98 wt% aerogel. The thickness of the composite article is preferably in the range of 3 mm to 500 mm.

[0156] It should be understood that any known filler can be included in the composite article of the present invention without any particular limitation.

[0157] The composite article can be otherwise defined by reference to its production method or its properties.

[0158] Thus, the composite article of the present invention can be defined as comprising aerogel particles and foam, wherein the composite article can be obtained by: impregnating an aerogel composition comprising aerogel powder and an organic solvent (A) and optionally an inorganic light-shielding agent and / or a mineral filler into a foam-containing article comprising foam, and partially or completely removing the organic solvent (A) to obtain the composite article.

[0159] The composite article can also be obtained by: injecting or impregnating or soaking an aerogel composition comprising aerogel powder, melamine-formaldehyde resin and an organic solvent (A) and optionally an inorganic light-shielding agent and / or a mineral filler into a foam-containing article comprising foam, and partially or completely removing the organic solvent (A) to obtain the composite article. In addition, the composite article can comprise a coating containing a melamine resin. The coating weight of the composite article is preferably in the range of 1 g / m 2 to 2000 g / m 2 in the range of, more preferably in the range of 2 g / m 2 to 1000 g / m2 within the range of, and even more preferably within 5 g / m 2 to 500 g / m 2 within the range of, and still more preferably within 10 g / m 2 to 300 g / m 2 As will be understood by those skilled in the art, the coating weight can be easily determined by changing the concentration of the coating composition (especially the amount of components other than the solvent in the coating composition) and / or the amount of the coating composition applied.

[0160] Based on the total weight of the composite article, the composite article preferably contains 0.1 - 20 wt% of melamine resin. Based on the total weight of the composite article, more preferably 0.5 - 18 wt%, and even more preferably 1 - 15 wt% of melamine resin.

[0161] Additionally or alternatively, the composite article can be defined as comprising aerogel particles and foam, wherein one or more of the following requirements (i)-(v) are met:

[0162] (i) The weight ratio of one or more aerogels to one or more foams in the composite article (aerogel / foam) is 1:8 or higher;

[0163] (ii) The thermal conductivity of the composite article at 0 °C is not higher than 0.030 W / m·K. Preferably, the thermal conductivity at 0 °C is not higher than 0.028 W / m·K, more preferably not higher than 0.026 W / m·K, even more preferably not higher than 0.024 W / m·K, and still more preferably not higher than 0.022 W / m·K;

[0164] (iii) The thermal conductivity of the composite article at 20 °C is not higher than 0.032 W / m·K. Preferably, the thermal conductivity at 20 °C is not higher than 0.030 W / m·K, more preferably not higher than 0.028 W / m·K, even more preferably not higher than 0.026 W / m·K, and still more preferably not higher than 0.024 W / m·K;

[0165] (iv) The thermal conductivity of the composite article at 40 °C is not higher than 0.034 W / m·K. Preferably, the thermal conductivity at 40 °C is not higher than 0.032 W / m·K, more preferably not higher than 0.030 W / m·K, even more preferably not higher than 0.028 W / m·K, and still more preferably not higher than 0.026 W / m·K.

[0166] (v) The burn-through time of the composite article is 10 minutes or longer, where the burn-through resistance is determined as follows: using a composite article in the form of a 16 cm x 16 cm sheet with a thickness of 8 mm, and treating the composite article at the center of its first major surface by using a propane gas burner (a flame source defined in DIN EN ISO 11925-2, flammability of products subjected to direct impingement of flame - Part 2: Single flame source test), where the burn-through time is the duration from the start of the flame treatment until the flame reaches the center of the second major surface.

[0167] The composite article can meet one or any number of possible combinations of requirements (i)-(v). For example, the composite article preferably meets requirement (i), or requirement (ii), or requirement (iii), or requirement (iv), or requirement (v). Alternatively, it preferably meets two requirements, such as (i) and (ii), (ii) and (iii), (iii) and (iv), (iv) and (v), (i) and (iii), (ii) and (iv), (iii) and (v), (i) and (iv), (ii) and (v), or (i) and (v). Alternatively, it preferably meets three requirements, such as (i) and (ii) and (iii), (i) and (ii) and (iv), (i) and (ii) and (v), (i) and (iii) and (iv), (i) and (iii) and (v), (i) and (iv) and (v), (ii) and (iii) and (iv), (ii) and (iii) and (v), (ii) and (iv) and (v), or (iii) and (iv) and (v). Alternatively, it preferably meets four or all of these requirements.

[0168] The composite article may also contain a melamine resin. Preferably, at least part of the melamine resin is present in the form of a coating. The coating weight of the composite article is preferably in the range of 1 g / m 2 to 2000 g / m 2 more preferably in the range of 2 g / m 2 to 1000 g / m 2 even more preferably in the range of 5 g / m 2 to 500 g / m 2 still more preferably in the range of 10 g / m 2 to 300 g / m 2 As will be understood by a person skilled in the art, the coating weight can be easily determined by changing the concentration of the coating composition (especially the amount of components other than the solvent in the coating composition) and / or the amount of the coating composition applied.

[0169] Based on the total weight of the composite article, the composite article preferably contains 0.1-20% by weight of melamine resin. Based on the total weight of the composite article, more preferably 0.5-18% by weight, even more preferably 1-15% by weight of melamine resin.

[0170] It should be understood that the composite article according to these alternative definitions may also contain an inorganic light-shielding agent and / or a mineral filler. Based on the total weight of the composite article, the composite article preferably contains 50-98% by weight, more preferably 60-96% by weight, still more preferably 70-95% by weight, or even 75-95% by weight, 80-95% by weight or 85-95% by weight, such as 88-92% by weight of aerogel. Preferably, the thickness of the composite article is in the range of 3 mm to 500 mm, more preferably in the range of 3-100 mm, still more preferably in the range of 3-50 mm, and even more preferably in the range of 5-30 mm. Additionally, when 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 are preferably met:

[0171]

[0172] wherein R is 100 or greater, preferably 1000 or greater, more preferably 10000 or greater,

[0173] wherein W / L is preferably in the range of 1000 / 1 - 1 / 1000,

[0174] wherein W / T is preferably 10 or greater, and

[0175] wherein L / T is preferably 10 or greater.

[0176] It should be understood that the composite article of the present invention may contain additional components, such as inert fillers or pigments, flame retardants, flame and smoke inhibitors, adhesives. Preferably, they can be added by including them in the aerogel composition.

[0177] The composite article of the present invention can also be coated with various other materials and / or combined with other materials such as textiles or laminates to form additional composite materials.

[0178] The present invention can be summarized by the following:

[0179] 1. A method for preparing a composite article comprising aerogel particles and foam, the method comprising:

[0180] providing a foam-containing article comprising foam,

[0181] providing an aerogel composition comprising aerogel powder and an organic solvent (A),

[0182] combining the foam-containing article with the aerogel composition, and

[0183] The organic solvent (A) is partially or completely removed to obtain the composite article.

[0184] 2. The method for preparing a composite article according to item 1, wherein the composite article further comprises an inorganic light-shielding agent and / or a mineral filler, and the step of providing an aerogel composition comprising an aerogel powder and an organic solvent (A) is the step of providing an aerogel composition comprising an aerogel powder and an organic solvent (A) and an inorganic light-shielding agent and / or a mineral filler.

[0185] 3. The method for preparing a composite article according to item 1 or 2, wherein the foam-containing article is a foam sheet.

[0186] 4. The method for preparing a composite article according to any one of items 1-3, wherein the density of the foam-containing article is 2-300 kg / m 3 , preferably 5-200 kg / m 3 , more preferably 6-150 kg / m 3 .

[0187] 5. The method for preparing a composite article according to any one of the foregoing items, wherein the open-cell ratio of the foam is 50% or more, preferably 60-99%, particularly 85-95% or 90-99%, and the open-cell ratio of the foam is preferably determined to be 40-99% according to ASTM D2856.

[0188] 6. The method for preparing a composite article according to any one of the foregoing items, wherein the foam comprises one or more selected from the group consisting of polyurethane foam, polyisocyanurate foam, melamine foam, phenolic foam, chemically crosslinked polyolefin foam, polypropylene foam, and mixtures thereof.

[0189] 7. The method for preparing a composite article according to any one of the foregoing items, wherein the foam comprises one or more selected from the group consisting of polyurethane (PUR) foam, melamine foam, and phenolic foam.

[0190] 8. The method for preparing a composite article according to any one of the foregoing items, wherein the foam comprises melamine foam.

[0191] 9. The method for preparing a composite article according to any one of the foregoing items, wherein the foam is chemically and / or physically crosslinked.

[0192] 10. The method for preparing a composite article according to any one of the foregoing items, wherein the organic solvent (A) is a hydrocarbon solvent, preferably selected from C 3-16 saturated, unsaturated or partially saturated hydrocarbons or mixtures thereof, more preferably selected from C 3-10Saturated straight-chain, branched or cyclic hydrocarbons or mixtures thereof, even more preferably selected from C 3-10 Straight-chain or branched alkanes or mixtures thereof, still more preferably selected from C 5-7 Straight-chain or branched alkanes or mixtures thereof, still even more preferably selected from hexane or heptane or mixtures thereof, most preferably n-hexane.

[0193] 11. The method for preparing a composite article according to any one of items 1-9, wherein the organic solvent (A) is an alcohol solvent, preferably selected from C 2-12 Saturated, unsaturated or partially saturated alcohols or mixtures thereof, more preferably selected from C 2-12 Saturated straight-chain, branched or cyclic alcohols or mixtures thereof, even more preferably selected from C 2-12 Saturated straight-chain, branched or cyclic monohydric alcohols or mixtures thereof, still more preferably selected from C 2-6 Saturated straight-chain, branched or cyclic monohydric alcohols or mixtures thereof, still even more preferably selected from propanol or mixtures thereof, most preferably 2-propanol.

[0194] 12. The 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 wherein the aerogel comprises silicon oxide or consists of silicon oxide, more preferably wherein the aerogel is a silica aerogel.

[0195] 13. The method for preparing a composite article according to any one of the preceding items, wherein the aerogel has a porosity of 85% or higher, more preferably 90% or higher, as determined by isothermal adsorption and desorption.

[0196] 14. The method for preparing a composite article according to any one of the preceding items, wherein the specific surface area of the aerogel is 300 m 2 / g or higher, preferably 400 m 2 / g or higher, preferably 500 m 2 / g or higher, preferably 600 m 2 / g or higher, and preferably 2000 m 2 / g or less, more preferably 1500 m 2 / g or less, even more preferably 1000 m 2 / g or less, determined according to DIN ISO9277 2003-05 (Determination of the specific surface area of solids by gas adsorption using the BET method).

[0197] 15. The method for preparing a composite article according to any one of the preceding items, wherein, by laser diffraction, preferably measured using a Malvern Mastersizer, the powder of the aerogel has a median particle size (d50) in the range of 1 - 50 μm, preferably 5 - 40 μm, more preferably 10 - 30 μm, and even more preferably 15 - 25 μm.

[0198] 16. The method for preparing a composite article according to any one of the preceding items, wherein the powder of the aerogel is obtained by a multiphase reaction.

[0199] 17. The method for preparing a composite article according to any one of the preceding items, wherein the powder of the aerogel is a silica aerogel powder, and the silica aerogel powder is obtained by: mixing deionized water, water glass, an organosilane compound, an inorganic acid, and an organic solvent (preferably a non-polar organic solvent) and reacting them to obtain primary silica hydrogel particles, performing solvent replacement on the primary silica hydrogel particles, and drying the gel particles after the solvent replacement is completed under ambient pressure to obtain the silica aerogel powder, preferably without using any further grinding or sieving treatment.

[0200] 18. The method for preparing a composite article according to item 1 or any one of items 3 - 17, wherein the aerogel composition is a dispersion of the aerogel powder in the organic solvent (A).

[0201] 19. The method for preparing a composite article according to item 1 and any one of items 3 - 18, wherein based on the total weight of the aerogel composition, the aerogel composition contains 2 - 20 wt% of the aerogel, preferably 4 - 18 wt% of the aerogel, more preferably 6 - 18 wt% of the aerogel, and even more preferably 10 - 18 wt% of the aerogel, and the remaining part is preferably the organic solvent (A).

[0202] 20. The method for preparing a composite article according to item 1 and any one of items 3 - 19, wherein the combined content of the aerogel powder and the organic solvent (A) in the aerogel composition is 90 wt% or more, preferably 95 wt% or more, more preferably 97 wt% or more, even more preferably 98 wt% or more, still more preferably 99 wt% or more, most preferably 99.5 wt% or more, or even 99.8 wt% or more.

[0203] 21. The method for preparing a composite article according to any one of items 2 - 17, wherein the aerogel composition is a dispersion of the aerogel powder, an inorganic light-shielding agent, and / or a mineral filler in the organic solvent (A).

[0204] 22. The method for preparing a composite article according to any one of items 2-17 and 21, wherein the inorganic light-shielding agent comprises or consists of one or more selected from iron oxide, zirconium oxide, titanium oxide, silicon carbide, and graphite, preferably wherein the inorganic light-shielding agent comprises or consists of one or more selected from iron oxide, zirconium oxide, and silicon carbide, and more preferably wherein the inorganic light-shielding agent is iron oxide or silicon carbide.

[0205] 23. The method for preparing a composite article according to any one of items 2-17, 21, and 22, wherein the mineral filler comprises or consists of one or more selected from metal hydroxides and hydrated carbonates, preferably wherein the mineral filler comprises or consists of one or more selected from aluminum hydroxide, magnesium hydroxide, hydromagnesite, and hydrocalcite, and more preferably wherein the mineral filler is one or both selected from magnesium hydroxide and aluminum hydroxide.

[0206] 24. The method for preparing a composite article according to any one of items 2-17 and 21-23, wherein based on the total weight of the aerogel composition, the aerogel composition contains 2-20 wt% of aerogel, preferably 4-18 wt% of aerogel, more preferably 6-18 wt% of aerogel, and even more preferably 10-18 wt% of aerogel, and the remaining part is preferably an organic solvent (A), an inorganic light-shielding agent, and a mineral filler.

[0207] 25. The method for preparing a composite article according to any one of items 2-17 and 21-24, wherein the combined content of the aerogel powder and the organic solvent (A) in the aerogel composition is 50 wt% or more, preferably 75 wt% or more, and more preferably 85 wt% or more.

[0208] 26. The method for preparing a composite article according to any one of items 2-17 and 21-25, wherein the combined content of the inorganic light-shielding agent and the mineral filler in the aerogel composition is 50 wt% or less, preferably 25 wt% or less, and more preferably 15 wt% or less.

[0209] 27. The method for preparing a composite article according to any one of the preceding items, wherein the aerogel composition comprises an aerogel powder, a melamine-formaldehyde resin, and an organic solvent.

[0210] 28. The method for preparing a composite article according to item 27, wherein the aerogel composition is a dispersion of the aerogel powder and the melamine-formaldehyde resin in the organic solvent.

[0211] 29. The method for preparing a composite article according to item 27 or 28, wherein the aerogel composition contains 2-20% by weight of aerogel, preferably 4-15% by weight of aerogel, more preferably 5-12% by weight of aerogel, even more preferably 6-10% by weight of aerogel, based on the total weight of the aerogel composition, and 0.1-20% by weight of melamine-formaldehyde resin, preferably 0.1-10% by weight of melamine-formaldehyde resin, more preferably 0.5-8% by weight of melamine-formaldehyde resin, even more preferably 1-7% by weight of melamine-formaldehyde resin, based on the total weight of the aerogel composition, and the balance is preferably an organic solvent.

[0212] 30. The method for preparing a composite article according to any one of items 27-29, wherein the combined content of 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, or even 99.8% by weight or more.

[0213] 31. The method for preparing a composite article according to any one of items 27-30, wherein the aerogel composition is a dispersion of the aerogel powder, melamine-formaldehyde resin, inorganic light-shielding agent and / or mineral filler in the organic solvent.

[0214] 32. The method for preparing a composite article according to any one of items 27-31, wherein the inorganic light-shielding agent comprises or consists of one or more selected from iron oxide, zirconium oxide, titanium oxide, silicon carbide and graphite, preferably wherein the inorganic light-shielding agent comprises or consists of one or more selected from iron oxide, zirconium oxide and silicon carbide, more preferably wherein the inorganic light-shielding agent is iron oxide or silicon carbide.

[0215] 33. The method for preparing a composite article according to any one of items 27-32, wherein the mineral filler comprises or consists of one or more selected from metal hydroxides and hydrated carbonates, preferably wherein the mineral filler comprises or consists of one or more selected from aluminum hydroxide, magnesium hydroxide, hydromagnesite and hydrocalcite, more preferably wherein the mineral filler is one or both of magnesium hydroxide and aluminum hydroxide.

[0216] 34. A method for preparing a composite article according to any one of items 27 - 33, wherein the aerogel composition contains 2 - 20 wt%, preferably 4 - 15 wt%, more preferably 5 - 12 wt%, even more preferably 6 - 10 wt% of aerogel based on the total weight of the aerogel composition, and 0.1 - 20 wt%, preferably 0.1 - 10 wt%, more preferably 0.5 - 8 wt% of melamine - formaldehyde resin based on the total weight of the aerogel composition, even more preferably 1 - 7 wt% of melamine - formaldehyde resin, and the remaining part is preferably an organic solvent and an inorganic light - shielding agent and a mineral filler.

[0217] 35. A method for preparing a composite article according to any one of items 27 - 34, wherein the combined content of aerogel powder, melamine formaldehyde resin and organic solvent in the aerogel composition is 50 wt% or more, preferably 75 wt% or more, more preferably 85 wt% or more.

[0218] 36. A method for preparing a composite article according to any one of items 27 - 35, wherein the combined content of inorganic light - shielding agent and mineral filler in the aerogel composition is 50 wt% or less, preferably 25 wt% or less, more preferably 15 wt% or less.

[0219] 37. A method for preparing a composite article according to any one of the preceding items, wherein the foam - containing article and the aerogel composition are combined by impregnating the aerogel composition into the foam - containing article.

[0220] 38. A method for preparing a composite article according to any one of the preceding items, wherein obtaining the composite article by drying to partially or completely remove the organic solvent (A) includes drying at a temperature of 50 - 150 °C for 1 - 8 hours, preferably drying at 100 - 120 °C for 1 - 48 hours.

[0221] 39. A method for preparing a composite article according to any one of the preceding items, wherein based on the total weight of the composite article, the composite article contains 50 - 98 wt%, preferably 60 - 96 wt%, more preferably 70 - 95 wt% of aerogel.

[0222] 40. A method for preparing a composite article according to any one of the preceding items, further comprising the step of coating the composite article with a coating composition containing melamine - formaldehyde resin.

[0223] 41. A method for preparing a composite article according to the preceding item, wherein the step of coating the composite article with a coating composition containing melamine - formaldehyde resin is carried out by spraying the coating composition onto the composite article to be coated.

[0224] 42. A method for preparing a composite article according to item 40 or 41, wherein the coating composition contains a melamine-formaldehyde resin and a solvent (B), and the solvent (B) preferably comprises an organic solvent and water.

[0225] 43. A method for preparing a composite article according to the previous item, wherein the organic solvent in the solvent (B) is an alcohol solvent (containing one or more alcohols), preferably selected from C 2-12 saturated, unsaturated or partially saturated alcohols or mixtures thereof, more preferably selected from C 2-12 saturated straight-chain, branched or cyclic alcohols or mixtures thereof, even more preferably selected from C 2-12 saturated straight-chain, branched or cyclic monohydric alcohols or mixtures thereof, still more preferably selected from C 2-6 saturated straight-chain, branched or cyclic monohydric alcohols (such as ethanol, 1-propanol, 2-propanol, butanol, pentanol (including cyclopentanol) or hexanol (including cyclohexanol)) or mixtures thereof, still even more preferably selected from propanol or mixtures thereof, and most preferably 2-propanol.

[0226] 44. A method for preparing a composite article according to item 42, wherein the solvent (B) is a mixture of isopropanol and water, and preferably contains 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.

[0227] 45. A method for preparing a composite article according to any one of items 40-44, wherein based on the total weight of the coating composition, the coating composition preferably contains 0.1-30% by weight of melamine-formaldehyde resin, preferably 1-25% by weight of melamine-formaldehyde resin, more preferably 3-22% by weight of aerogel melamine-formaldehyde resin, even more preferably 5-20% by weight of melamine-formaldehyde resin, still more preferably 10-20% by weight of melamine-formaldehyde resin, and even still more preferably 12-18% by weight of melamine-formaldehyde resin.

[0228] 46. A method for preparing a composite article according to any one of items 40-45, wherein based on the total weight of the coating composition, the combined content of the melamine-formaldehyde resin and the solvent (B) in the coating 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, or even 99.8% by weight or more.

[0229] 47. A method for preparing a composite article according to any one of items 40 - 46, wherein the step of coating the composite article with a coating composition comprising a melamine - formaldehyde resin is followed by heating to a temperature of at least 100 °C for at least 10 minutes (preferably 1 hour), preferably to a temperature of 120 - 180 °C for 1 - 8 hours.

[0230] 48. A method for preparing a composite article according to any one of items 40 - 47, wherein the composite article contains 15 - 70 wt% of aerogel, preferably 20 - 60 wt%, more preferably 30 - 50 wt% of aerogel based on the total weight of the composite article, and contains 0.1 - 20 wt%, preferably 0.5 - 18 wt%, even more preferably 1 - 15 wt% of melamine resin based on the total weight of the composite article.

[0231] 49. A method for preparing a composite article according to any one of the preceding items, wherein the thickness of the composite article is 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, even more preferably in the range of 5 - 30 mm.

[0232] 50. A method for preparing a composite article according to any one of the preceding items, wherein when 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 are met:

[0233]

[0234] wherein R is 100 or greater, preferably 1000 or greater, more preferably 10000 or greater,

[0235] wherein W / L is preferably in the range of 1000 / 1 - 1 / 1000,

[0236] wherein W / T is preferably 10 or greater, and

[0237] wherein L / T is preferably 10 or greater.

[0238] 51. A method for preparing a composite article according to any one of the preceding items, wherein the composite article contains less than 15 wt% of organic compounds other than melamine resin and foam material, preferably less than 10 wt% of organic compounds other than melamine resin and foam material, more preferably less than 5 wt% of organic compounds other than melamine resin and foam material, wherein the term organic compound refers to any compound containing at least one carbon - hydrogen bond.

[0239] 52. A method for preparing a composite article according to any one of the preceding items, wherein the composite article contains less than 10% by weight of a binder, preferably less than 5% by weight of a binder, more preferably less than 2% by weight of a binder, even more preferably less than 1% by weight of a binder, still more preferably less than 0.5% by weight of a binder, and most preferably less than 0.1% by weight of a binder.

[0240] 53. A composite article obtainable by a method according to any one of the preceding items.

[0241] 54. A composite article comprising aerogel particles and a foam, wherein the composite article is obtainable by: injecting or impregnating or soaking an aerogel composition comprising an aerogel powder and an organic solvent (A) and optionally an inorganic light-shielding agent and / or a mineral filler into a foam-containing article comprising a foam, and partially or completely removing the organic solvent (A) to obtain the composite article.

[0242] 55. The composite article according to item 54, wherein the composite article is obtainable by: injecting or impregnating or soaking an aerogel composition comprising an aerogel powder, a melamine-formaldehyde resin, and an organic solvent (A) and optionally an inorganic light-shielding agent and / or a mineral filler into a foam-containing article comprising a foam, and partially or completely removing the organic solvent (A) to obtain the composite article.

[0243] 56. The composite article according to item 54 or 55, wherein the composite article further comprises a coating containing a melamine resin.

[0244] 57. A composite article comprising aerogel particles and a foam, wherein one or more of the following requirements (i)-(v) are satisfied:

[0245] (i) The weight ratio of one or more aerogels to one or more foams (aerogel / foam) in the composite article is 1:8 or higher;

[0246] (ii) The thermal conductivity of the composite article at 0 °C is not higher than 0.030 W / m·K. Preferably, the thermal conductivity at 0 °C is not higher than 0.028 W / m·K, more preferably not higher than 0.026 W / m·K, even more preferably not higher than 0.024 W / m·K, still more preferably not higher than 0.022 W / m·K;

[0247] (iii) The thermal conductivity of the composite article at 20 °C is not higher than 0.032 W / m·K. Preferably, the thermal conductivity at 20 °C is not higher than 0.030 W / m·K, more preferably not higher than 0.028 W / m·K, even more preferably not higher than 0.026 W / m·K, still more preferably not higher than 0.024 W / m·K;

[0248] (iv) The thermal conductivity of the composite product at 40 °C is not higher than 0.034 W / m·K. Preferably, the thermal conductivity at 40 °C is not higher than 0.032 W / m·K, more preferably not higher than 0.030 W / m·K, even more preferably not higher than 0.028 W / m·K, still more preferably not higher than 0.026 W / m·K.

[0249] (v) The burn-through time of the composite product is 10 minutes or longer, where the burn-through resistance is determined as follows: Use a composite product in the form of a 16 cm x 16 cm sheet with a thickness of 8 mm, and treat the composite product at the center of its first major surface by using a propane gas burner (a flame source defined in DIN EN ISO 11925-2, flammability of products subjected to direct impingement of flame - Part 2: Single-flame source test), where the burn-through time is the duration from the start of the flame treatment until the flame reaches the center of the second major surface.

[0250] 58. The composite product according to item 57, further comprising an inorganic light-shielding agent and / or a mineral filler.

[0251] 59. The composite product according to item 58, wherein the composite product further comprises a melamine resin.

[0252] 60. The composite product according to item 59, wherein at least part of the melamine resin exists in the form of a coating.

[0253] 61. The composite product according to any one of items 57 - 60, wherein the composite product contains less than 15% by weight of organic compounds other than the melamine resin and the foam material, preferably less than 10% by weight of organic compounds other than the melamine resin and the foam material, more preferably less than 5% by weight of organic compounds other than the melamine resin and the foam material, where the term organic compound refers to any compound containing at least one carbon-hydrogen bond.

[0254] 62. The composite product according to any one of items 57 - 61, wherein the composite product contains less than 10% by weight of an adhesive, preferably less than 5% by weight of an adhesive, more preferably less than 2% by weight of an adhesive, even more preferably less than 1% by weight of an adhesive, still more preferably less than 0.5% by weight of an adhesive, and most preferably less than 0.1% by weight of an adhesive.

[0255] 63. The composite product according to any one of items 57 - 62, wherein based on the total weight of the composite product, the composite product contains 50 - 98% by weight, preferably 60 - 96% by weight, more preferably 70 - 95% by weight of aerogel.

[0256] 64. The composite article according to any one of items 57 - 63, wherein the thickness of the composite article is 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 - 30 mm.

[0257] 65. The composite article according to any one of items 57 - 64, wherein when 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 are met:

[0258]

[0259] where R is 100 or greater, preferably 1000 or greater, more preferably 10000 or greater,

[0260] where W / L is preferably in the range of 1000 / 1 - 1 / 1000,

[0261] where W / T is preferably 10 or greater, and

[0262] where L / T is preferably 10 or greater. Examples

[0263] Example 1

[0264] Materials

[0265] Aerogel powder (JIOS AeroVa aerogel powder, D20 grade)

[0266] Melamine open - cell foam (Basotect B, BASF), with thicknesses of 8, 14, and 25 mm and a density of 9 kg / m 3

[0267] n - Hexane (industrial grade)

[0268] 2 - Propanol (industrial grade)

[0269] Experiments

[0270] Using standard laboratory mixing equipment, more specifically a propeller mixer (Heidolph overhead stirrer RZR2020), the aerogel was dispersed in 2 - propanol or n - hexane to achieve a solids content of 10 - 14 wt%.

[0271] The melamine open - cell foam (Basotect B, BASF) with thicknesses of 8, 14, and 25 mm was treated by pouring the aerogel dispersion described above onto the substrate until saturation. Subsequently, after drying to remove the carrier solvent, an aerogel - filled foam with an aerogel content even greater than 90 wt% was obtained:

[0272]

[0273]

[0274] Results and evaluation

[0275] The main characteristics of these filled foams include low thermal conductivity and low dust emission. In addition, the filled foams have unexpectedly high flexibility, almost as high as that of the unfilled foams. The filled foams are also easy to cut and handle, and have a very low density, only about 100 kg / m 3 .

[0276] These foams self-extinguish when in direct contact with a flame and have improved combustibility behavior compared to the unfilled foams.

[0277] The characterization results and photos of these prototypes are shown in the following figures:

[0278] Figure 1 : Thermal conductivity values of Comparative Example 1 and Examples 1 - 3

[0279] Figure 2 : Photos of Examples 2, 4, and 5

[0280] Figure 3 : The filled foam shows surprisingly high flexibility ( Figure 3 b), with little difference from the unfilled foam used as a reference ( Figure 3 a) (Example 4). No obvious dust emission was observed when bending the filled foam sample:

[0281] Figure 4 : The micrograph of Example 2 shows a high filling degree and aerogel agglomeration behavior compared to the unfilled reference ( Figure 4 a) ( Figure 4 b):

[0282] Figure 5 : Photo of Example 2 taken after exposure to direct flame. Flame penetration is significantly hindered in the filled foam, and no burn-through occurred even after 10 minutes of direct exposure:

[0283] Figure 5 a and 5c: Unfilled foam (Comparative Example 1): Burn-through after exposure to direct flame (5a: burned side; 5c: unexposed side).

[0284] Figure 5 b and 5d: Filled foam (Example 2): No burn-through even after 10 minutes (5b: burned side; 5d: unexposed side).

[0285] Analysis and tests carried out

[0286] 2.1 Microscopic imaging

[0287] The surface morphology of the samples was observed under an Olympus SZX7 stereomicroscope equipped with an Olympus DF Plapo 1x-4 objective lens.

[0288] 2.2 Fire resistance test

[0289] To study the fire resistance performance, the samples were exposed to direct flame impingement. The samples were cut into a size of 16x16 cm and exposed to a burner in the European Class E fire test (DIN EN ISO 11925-2), which uses commercially available propane gas with a purity of at least 95% and a gas pressure of 10 kPa to 50 kPa.

[0290] 2.3 Thermal conductivity

[0291] According to the standard DIN EN 12667, the thermal conductivity was measured by using the heat flow meter method and a LaserComp Fox 200 device. The samples were cut into a size of 20x20 cm, and their thermal conductivities at 0, 10, 20, and 40 °C were recorded as the results.

Claims

1. A method for preparing a composite article comprising aerogel particles and foam, the method comprising: Provided is a foam-containing foam product, Provided is an aerogel composition containing aerogel powder and an organic solvent (A), Combining the foam-containing foam product with the aerogel composition, and Partially or completely removing the organic solvent (A) to obtain the composite product.

2. The method for preparing a composite article according to claim 1, wherein the density of the foam-containing article is 2 - 300 kg / m 3 , preferably 5 - 200 kg / m 3 , more preferably 6 - 150 kg / m 3 .

3. The method for preparing a composite article according to claim 1 or 2, wherein the open-cell ratio of the foam is 50% or more, preferably 60 - 99%, particularly 85 - 95% or 90 - 99%.

4. The method for preparing a composite article according to any one of the preceding claims, wherein the foam comprises one or more selected from the group consisting of polyurethane foam, polyisocyanurate foam, melamine foam, phenolic foam, chemically crosslinked polyolefin foam, polypropylene foam, and mixtures thereof.

5. The method for preparing a composite article according to any one of the preceding claims, wherein the foam comprises melamine foam.

6. The method for preparing a composite article according to any one of the preceding claims, wherein based on the total weight of the aerogel composition, the aerogel composition contains 2 - 20% by weight of aerogel, preferably 4 - 18% by weight of aerogel, more preferably 6 - 18% by weight of aerogel, even more preferably 10 - 18% by weight of aerogel, and the balance is preferably an organic solvent (A).

7. The method for preparing a composite article according to any one of the preceding claims, wherein the aerogel composition comprises aerogel powder, melamine - formaldehyde resin, and an organic solvent.

8. The method for preparing a composite article according to any one of the preceding claims, wherein the foam-containing article and the aerogel composition are combined by impregnating the aerogel composition into the foam-containing article.

9. The method for preparing a composite article according to any one of the preceding claims, wherein obtaining the composite article by drying to partially or completely remove the organic solvent (A) comprises drying at a temperature of 50 - 150 °C for 1 - 48 hours, preferably drying at a temperature of 100 - 120 °C for 1 - 48 hours.

10. A method for preparing a composite article according to any one of the preceding claims, further comprising the step of coating the composite article with a coating composition comprising a melamine-formaldehyde resin.

11. A composite article obtainable by a method according to any one of the preceding claims.

12. A composite article comprising aerogel particles and foam, wherein one or more of the following requirements (i)-(v) are met: (i) The weight ratio of one or more aerogels to one or more foams in the composite article (aerogel / foam) is 1:8 or higher; (ii) The thermal conductivity of the composite article at 0 °C is not higher than 0.030 W / m·K. Preferably, the thermal conductivity at 0 °C is not higher than 0.028 W / m·K, more preferably not higher than 0.026 W / m·K, even more preferably not higher than 0.024 W / m·K, still more preferably not higher than 0.022 W / m·K; (iii) The thermal conductivity of the composite article at 20 °C is not higher than 0.032 W / m·K. Preferably, the thermal conductivity at 20 °C is not higher than 0.030 W / m·K, more preferably not higher than 0.028 W / m·K, even more preferably not higher than 0.026 W / m·K, still more preferably not higher than 0.024 W / m·K; (iv) The thermal conductivity of the composite article at 40 °C is not higher than 0.034 W / m·K. Preferably, the thermal conductivity at 40 °C is not higher than 0.032 W / m·K, more preferably not higher than 0.030 W / m·K, even more preferably not higher than 0.028 W / m·K, still more preferably not higher than 0.026 W / m·K. (v) The burn-through time of the composite article is 10 minutes or longer, wherein the burn-through resistance is determined as follows: using a composite article in the form of a 16 cm x 16 cm sheet with a thickness of 8 mm, and treating the composite article at the center of its first major surface with a propane gas burner (a flame source defined in DIN EN ISO 11925-2, flammability of products subjected to direct impingement of flame - Part 2: Single flame source test), wherein the burn-through time is the duration from the start of the flame treatment until the flame reaches the center of the second major surface.

13. The composite article according to claim 11 or 12, wherein the composite article contains 0.1-20% by weight of a melamine resin, based on the total weight of the composite article.

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