Reaction mixture for the manufacture of a closed-cell rigid polyurethane or polyisocyanurate based foam comprising inorganic fillers

Abstract

The present invention relates to a reaction mixture for the manufacture of a closed-cell rigid polyurethane or polyisocyanurate (PU or PIR) based foam based on inorganic fillers, said foam having a calorific value lower than 6 MJ / kg, preferably lower than 4.5 MJ / kg, more preferably lower than 3 MJ / kg, measured according to EN ISO 1716, comprising: - at least one polyisocyanate containing compound; - at least one isocyanate-reactive compound; - an inorganic filler composition; - at least one physical blowing agent; characterized in that the inorganic filler composition has a bulk density higher than 2 g / cm 3 , preferably higher than 2.1 g / cm 3 , more preferably higher than 2.2 g / cm 3 , even more preferably higher than 2.4 g / cm 3 .

Description

Technical Field

[0001] This invention relates to a reaction mixture for manufacturing a foam containing closed-cell rigid polyurethane or polyisocyanurate (PU / PIR) based on inorganic fillers. Background Technology

[0002] Foams containing rigid PU / PIR have excellent thermal insulation properties and are therefore commonly used in building applications for building insulation, such as composite panels and insulation boards. However, compared to glass wool or mineral wool, which are known as inorganic-based insulation products, foams containing rigid PU / PIR still have poor fire resistance.

[0003] Typically, foams containing rigid PU / PIR have a calorific value in the range of 25-30 MJ / kg. The goal is to reduce this value while maintaining a low density (<400 kg / m³). 3 The competitive λ value (<35mW / mK at 10℃) remains challenging.

[0004] Therefore, there is a need for a reaction mixture that is readily processable and suitable for providing inorganic filler-based closed-cell rigid polyurethane or polyisocyanurate (PU / PIR) foams with improved properties, particularly in terms of density, calorific value, and λ value. Summary of the Invention

[0005] The object of the present invention is to overcome the above-mentioned disadvantages by providing a reaction mixture suitable for manufacturing inorganic filler-based foams containing closed-cell rigid polyurethane or polyisocyanurate (PU / PIR) with a calorific value of less than 6 MJ / kg, preferably less than 4.5 MJ / kg, more preferably less than 3 MJ / kg, according to EN ISO 1716. The reaction mixture comprises:

[0006] - At least one compound containing a polyisocyanate;

[0007] - At least one isocyanate reactive compound;

[0008] -Inorganic filler composition;

[0009] -At least one physical foaming agent;

[0010] -Optional surfactants, chemical foaming agents, catalysts, chain extenders, crosslinking agents, antioxidants, flame retardants and / or mixtures thereof;

[0011] The inorganic filler composition is characterized by having a bulk density higher than 2 g / cm³. 3 Preferably higher than 2.1 g / cm³ 3 More preferably, higher than 2.2 g / cm³3 Even better, higher than 2.4 g / cm³ 3 .

[0012] Surprisingly, the bulk density of the inorganic filler composition is higher than 2 g / cm³. 3 Preferably higher than 2.1 g / cm³ 3 More preferably, higher than 2.2 g / cm³ 3 Even better, higher than 2.4 g / cm³ 3 This enables the provision of an inorganic filler-based foam comprising closed-cell rigid PU / PIR (hereinafter referred to as "the foam") that possesses appropriate (or even improved) mechanical properties without adversely affecting foam stability during expansion. It also means that the foam's cells can remain closed throughout the foam's lifespan.

[0013] Furthermore, the reaction mixture of the present invention is suitable for providing the foam of the present invention, which may have a calorific value of less than 6 MJ / kg while maintaining a low density (<400 kg / m³). 3 ) and competitive λ value (<35mW / mK, at 10℃).

[0014] This advantage can be advantageous in the field of insulation, especially in thermal insulation barriers.

[0015] Furthermore, when the components of the reaction mixture are mixed together, the inorganic filler composition is observed to be well dispersed in the foam, which is a high-quality foam, particularly suitable for rigid foam applications.

[0016] Another advantage relies on the ease of processing reaction mixtures suitable for foam production, where lower-volume inorganic filler compositions can be processed during mixing with easier homogenization and lower viscosity, compared to known reaction mixtures containing fillers with lower bulk density.

[0017] Advantageously, pure compounds or mixtures can be used to provide bulk densities higher than 2 g / cm³. 3 Preferably, the concentration is higher than 2.1 g / cm³. 3 More preferably, higher than 2.2 g / cm³ 3 Even better, higher than 2.4 g / cm³ 3 Inorganic filler compositions. Barium sulfate (also known as barite) has a bulk density typically higher than 2 g / cm³. 3 Examples of inorganic packing materials.

[0018] When the inorganic filler composition contains at least 80 wt%, preferably more than 85 wt%, of (pure) barium sulfate (which preferably has a suitable particle size distribution), the bulk density of the inorganic filler composition can even increase to about 3 g / cm³. 3.

[0019] According to a preferred embodiment of the invention, the inorganic filler composition is present in an amount of at least 70 wt%, preferably at least 80 wt%, more preferably at least 85 wt%, relative to the total weight of the reaction mixture, without taking into account the weight of the at least one physical foaming agent. This embodiment can satisfy thermal insulation and fire resistance properties (e.g., calorific value less than 6 MJ / kg, preferably less than 4.5 MJ / kg, more preferably less than 3 MJ / kg), particularly when the reaction mixture of the invention is used to manufacture the foam of the invention.

[0020] Preferably, the inorganic filler composition comprises a first inorganic filler selected from bismuth oxide, zirconium oxide (IV), iron oxide (III), barium sulfate, barium carbonate, titanium oxide (IV), aluminum oxide, magnesium oxide, and combinations thereof.

[0021] More preferably, the reaction mixture of the present invention, wherein the thermal conductivity of the inorganic filler composition is less than 25 W / m·K, preferably less than 10 W / m·K, and even more preferably less than 5 W / m·K. This has the advantage that when the reaction mixture of the present invention is used to manufacture foam, the λ value can be further reduced.

[0022] According to a specific embodiment, the inorganic filler composition comprises at least 50 wt%, preferably at least 70 wt%, more preferably at least 80 wt%, and even more preferably at least 90 wt% of the at least one first filler, based on the total weight of the inorganic filler composition.

[0023] In a more preferred embodiment of the present invention, the first inorganic filler has the following particle size distribution: the d90 value is in the range of 10-2000 μm, more preferably in the range of 100-2000 μm, and even more preferably in the range of 300-2000 μm.

[0024] Regarding the characteristics related to the particle size distribution in the inorganic filler composition, it is advantageous to note that having different sizes (small and large sizes) mixed together in the first inorganic filler / the inorganic filler composition also contributes to improved processing and foam quality, as well as finer pores, improved mechanical properties, while maintaining high-quality thermal insulation properties in the final product, particularly in the foam of the present invention.

[0025] Advantageously, the inorganic filler composition further comprises a bulk density of less than 2 g / cm³. 3The second inorganic filler is preferably selected from: aluminum silicate, magnesium silicate, calcium fluoride, ferric sulfate (III), calcium sulfate, calcium carbonate, magnesium sulfate, silicon dioxide, sodium carbonate, aluminum hydroxide, magnesium hydroxide, sodium chloride, calcium chloride, perlite, and combinations thereof. This allows for a bulk density higher than 2 g / cm³. 3 The filler and bulk density are less than 2 g / cm³ 3 The packing material is more convenient for handling the reaction mixture of the present invention. It provides users with greater tolerance, and the option is also relatively inexpensive.

[0026] According to a specific embodiment, the inorganic filler composition comprises at least 50 wt%, preferably at least 70 wt%, more preferably at least 80 wt%, and even more preferably at least 90 wt% of the at least one second filler, based on the total weight of the inorganic filler composition.

[0027] It should be noted that even if the inorganic filler composition may contain the aforementioned second inorganic filler, the inorganic filler composition should still have a total content greater than 2 g / cm³. 3 The bulk density is adjusted to achieve the properties described in this invention when manufacturing foam.

[0028] Furthermore, in a preferred embodiment of the invention, the at least one physical blowing agent is selected from: isobutylene, dimethyl ether, methylene chloride, acetone, chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs), hydrofluoroolefins (HFO / HCFO), dialkyl ethers, cycloalkylene ethers, ketones, fluorinated ethers, perfluorocarbons, hydrocarbons, and mixtures thereof. This allows for a further reduction in the λ value of the final product, which is particularly advantageous.

[0029] More advantageously, the at least one polyisocyanate-containing compound is selected from: toluene diisocyanate, methylene diphenyl diisocyanate, polyisocyanate compositions containing methylene diphenyl diisocyanate, and mixtures thereof.

[0030] In a particularly preferred embodiment, the at least one isocyanate reactive compound is a polyol having an average hydroxyl number of 50-1000 and preferably having a hydroxyl functionality of 2-8.

[0031] In another embodiment of the invention, the reaction mixture contains a CO2 scavenger (NaOH, KOH, epoxide, etc.), which helps to further reduce the λ value of the final product.

[0032] The reaction mixture of the present invention can be characterized by combining all of the above features.

[0033] The reaction mixture of the present invention is suitable for manufacturing any rigid foam for which a combination of low λ, low density and excellent fire resistance is desired.

[0034] Preferably, the reaction mixture of the present invention is suitable for manufacturing foams based on inorganic fillers comprising closed-cell rigid polyurethane or polyisocyanurate (PU / PIR). The latter has several technical features:

[0035] (i) A calorific value of less than 6 MJ / kg, preferably less than 4.5 MJ / kg, more preferably less than 3 MJ / kg, as measured according to EN ISO 1716;

[0036] (ii) λ value below 35 mW / mK at 10 °C, measured according to ISO 8301;

[0037] (iii) Below 400 kg / m 3 Preferred weight is below 300 kg / m³ 3 More preferably, below 200 kg / m 3 Even better is 100-180 kg / m 3 Density within the specified range, measured according to ISO 845;

[0038] (iv) A closed-cell percentage of more than 50%, preferably more than 70%, more preferably more than 80%, as measured according to ISO 4590.

[0039] The combination of the above features enables the provision of a reaction mixture suitable for manufacturing the foam of the present invention. Compared with known foams, this foam has improved fire resistance and thermal insulation properties.

[0040] Additional features are listed in the Examples section.

[0041] The present invention also relates to a foam based on inorganic fillers comprising closed-cell rigid polyurethane or polyisocyanurate (PU or PIR), said foam having the following calorific value: less than 6 MJ / kg, preferably less than 4.5 MJ / kg, more preferably less than 3 MJ / kg, as measured according to EN ISO 1716.

[0042] Preferably, the foam of the present invention has a λ value of less than 35 mW / mK at 10°C, as measured according to ISO 8301.

[0043] In a particularly preferred embodiment of the invention, a low λ value (below 50 mW / mK) is also observed at higher temperatures (e.g., 100 °C) due to the use of the filler composition of the invention.

[0044] More preferably, the foam of the present invention has the following density: less than 400 kg / m³ 3Preferably below 300 kg / m 3 More preferably, below 200 kg / m 3 Even better is 100-180 kg / m 3 Within the range, measured according to ISO 845.

[0045] Advantageously, the percentage of closed pores is greater than 50%, preferably greater than 70%, and more preferably greater than 80%, as measured according to ISO 4590.

[0046] More advantageously, the foam of the present invention is obtained or can be obtained by mixing the components of the reaction mixture of the present invention.

[0047] The various characteristics of the above-described reaction mixture also apply to the foam of the present invention, and can therefore be used to define foam obtained by mixing the components of the reaction mixture of the present invention.

[0048] Other embodiments of the foam of the present invention are mentioned in the Examples section.

[0049] The present invention also relates to articles comprising the foam of the present invention.

[0050] Other embodiments of the foam of the present invention are mentioned in the Examples section.

[0051] The present invention also relates to the use of the articles of the invention in rigid thermal insulation foam applications, particularly in composite panels, insulation boards, external thermal insulation composite systems (ETICS), piping, garage doors, equipment, and sprayed foam insulation applications.

[0052] Other embodiments of the invention are described in the Examples section.

[0053] The present invention also relates to a method for manufacturing a foam based on inorganic fillers comprising closed-cell rigid polyurethane or polyisocyanurate (PU or PIR), the method comprising mixing the following components:

[0054] - At least one compound containing a polyisocyanate;

[0055] - At least one isocyanate reactive compound;

[0056] -Inorganic filler composition;

[0057] -At least one physical foaming agent;

[0058] -Optional surfactants, chemical foaming agents, catalysts, chain extenders, crosslinking agents, antioxidants, flame retardants and / or mixtures thereof;

[0059] The inorganic filler composition is characterized by having a bulk density higher than 2 g / cm³. 3 Preferably higher than 2.1 g / cm³ 3More preferably, higher than 2.2 g / cm³ 3 Even better, higher than 2.4 g / cm³ 3 .

[0060] Advantageously, the inorganic filler compositions of the present invention can be provided as pure compounds or mixtures. Barium sulfate (also known as barite) has a bulk density typically higher than 2 g / cm³. 3 Examples of inorganic packing materials.

[0061] When the inorganic filler composition contains at least 80 wt%, preferably more than 85 wt%, of barium sulfate, it preferably has a suitable particle size distribution, and the bulk density of the inorganic filler composition can even be increased to as high as about 3 g / cm³. 3 .

[0062] According to a preferred embodiment of the invention, the inorganic filler composition is present in an amount of at least 70 wt%, preferably at least 80 wt%, more preferably at least 85 wt%, relative to the total weight of the reaction mixture, regardless of the weight of the at least one physical foaming agent. This embodiment enables the achievement of thermal insulation and fire resistance properties (e.g., calorific value below 6 MJ / kg, preferably below 4.5 MJ / kg, more preferably below 3 MJ / kg), particularly when using the reaction mixture of the invention to manufacture the foam of the invention.

[0063] Preferably, the inorganic filler composition comprises a first inorganic filler selected from bismuth oxide, zirconium oxide (IV), iron oxide (III), barium sulfate, barium carbonate, titanium oxide (IV), aluminum oxide, magnesium oxide, and combinations thereof.

[0064] More preferably, in the reaction mixture according to any of the foregoing embodiments, the thermal conductivity of the inorganic filler composition is less than 25 W / mK, preferably less than 10 W / mK, and even more preferably less than 5 W / mK, which is beneficial for further reducing the λ value.

[0065] According to a specific implementation, the inorganic filler composition comprises at least 50 wt%, preferably at least 70 wt%, more preferably at least 80 wt%, and even more preferably at least 90 wt% of the at least one first filler, based on the total weight of the inorganic filler composition.

[0066] In a more preferred embodiment of the present invention, the first inorganic filler has the following particle size distribution: the d90 value is in the range of 10-2000 μm, more preferably in the range of 100-2000 μm, and even more preferably in the range of 300-2000 μm.

[0067] Regarding the characteristics related to the particle size distribution in the inorganic filler composition, it is advantageous to note that having different sizes (small and large sizes) mixed together in the first inorganic filler / the inorganic filler composition also contributes to improved processing and foam quality, as well as finer pores, improved mechanical properties, while maintaining high-quality thermal insulation properties in the final product, particularly in the foam of the present invention.

[0068] Advantageously, the inorganic filler composition further comprises a bulk density of less than 2 g / cm³. 3 The second inorganic filler is preferably selected from: aluminum silicate, magnesium silicate, calcium fluoride, ferric sulfate (III), calcium sulfate, calcium carbonate, magnesium sulfate, silicon dioxide, sodium carbonate, aluminum hydroxide, magnesium hydroxide, sodium chloride, calcium chloride, perlite, and combinations thereof. This allows for a bulk density higher than 2 g / cm³. 3 The filler and bulk density are less than 2 g / cm³ 3 The packing material is more convenient for handling the reaction mixture of the present invention. It provides users with greater tolerance, and the option is also relatively inexpensive.

[0069] Furthermore, in a preferred embodiment of the invention, the at least one physical blowing agent is selected from: isobutylene, dimethyl ether, methylene chloride, acetone, chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs), hydrofluoroolefins (HFO / HCFO), dialkyl ethers, cycloalkylene ethers, ketones, fluorinated ethers, perfluorocarbons, hydrocarbons, and mixtures thereof. This allows for a further reduction in the λ value of the final product, which is particularly advantageous.

[0070] More advantageously, the at least one polyisocyanate-containing compound is selected from: toluene diisocyanate, methylene diphenyl diisocyanate, polyisocyanate compositions containing methylene diphenyl diisocyanate, and mixtures thereof.

[0071] In a particularly preferred embodiment, the at least one isocyanate reactive compound is a polyol having an average hydroxyl number of 50-1000 and preferably having a hydroxyl functionality of 2-8.

[0072] In another embodiment of the invention, the reaction mixture contains a CO2 scavenger (NaOH, KOH, epoxide, etc.), which helps to further reduce the λ value of the final product. Detailed Implementation

[0073] In the context of this invention, the following terms have the following meanings:

[0074] Isocyanate index or NCO index or index :

[0075] The ratio of NCO- groups to isocyanate reactive hydrogen atoms in the formulation is given as a percentage:

[0076] (%)

[0077] In other words, the NCO index represents the percentage of the isocyanate actually used in the formulation relative to the theoretically required amount of isocyanate to react with the amount of reactive hydrogen in the isocyanate used in the formulation.

[0078] It should be observed that the isocyanate index used herein is considered from the perspective of the actual polymerization process involving the preparation of materials containing isocyanate components and isocyanate reactive components. Any isocyanate groups consumed in the preparatory steps for the production of modified polyisocyanates (including such isocyanate derivatives referred to in the art as prepolymers) or any active hydrogen consumed in the preparatory steps (e.g., reacting with isocyanates to produce modified polyols or polyamines) are not included in the calculation of the isocyanate index. Only free isocyanate groups and free isocyanate reactive hydrogen (including those hydrogens of water if water is used) present in the actual polymerization stage are considered.

[0079] The term "reaction mixture" should be understood as a combination of compounds in which the polyisocyanate is held in one or more containers separate from the isocyanate reactive components.

[0080] The terms “isocyanate reactive compound” and “isocyanate reactive hydrogen atom” used in this article for calculating the isocyanate index refer to the total number of active hydrogen atoms present in the hydroxyl and amine groups of the isocyanate reactive compound; this means that in order to calculate the isocyanate index in the actual polymerization process, one hydroxyl group is considered to contain one reactive hydrogen, one primary amine group is considered to contain one reactive hydrogen, and one water molecule is considered to contain two active hydrogens.

[0081] The statement "particle size distribution with d90 value" should be understood to mean that 90% of the sample mass consists of particles smaller than a given d90 value. This particle size distribution can be obtained using DIN 53195.

[0082] The term "foam containing closed-cell rigid polyurethane (PU) based on inorganic fillers" should be understood as foam containing a urethane structure (PUR) manufactured with an isocyanate index in the range of 80-130, preferably in the range of 100-130.

[0083] The term "foam containing closed-cell rigid polyisocyanurate (PIR) based on inorganic fillers" refers to a foam containing a urethane and isocyanate structure (PIR-PUR) manufactured with an isocyanate index of 130 or higher, more preferably higher than 220, preferably in the presence of a suitable trimerizing catalyst (e.g., potassium acetate or potassium octanoate).

[0084] In the context of this invention, the term "foam" may also advantageously include epoxides capable of reacting with isocyanates to generate oxazolidinone units.

[0085] The term “mean nominal hydroxyl functionality” (or simply “functionality”) is used herein to refer to the number-average functionality (number of hydroxyl groups per molecule) of a polyol or polyol composition, assumed to be the number-average functionality (number of active hydrogen atoms per molecule) of one or more initiators used in their preparation, although it is usually slightly lower in practice due to some terminal unsaturation.

[0086] The term "average" refers to the exponential average unless otherwise stated.

[0087] The term "tripolymer catalyst" used in this article refers to a catalyst capable of catalyzing (promoting) the formation of isocyanurate groups from polyisocyanates. This means that isocyanates can react with each other to form macromolecules with isocyanurate structures (polyisocyanurate = PIR). Reactions between isocyanate-polyols and isocyanate-isocyanates (homopolymerization) can occur simultaneously or directly alternately, thereby forming macromolecules with urethane and isocyanurate structures (PIR-PUR).

[0088] In the context of this invention, the "bulk density" (e.g., of the filler compositions of this invention) is defined as its mass divided by the volume it occupies. Bulk density can be determined according to DIN EN 1097-3.

[0089] The thermal conductivity of the filler can be determined according to ISO 22007-2.

[0090] According to the implementation scheme, the at least one isocyanate-containing compound used in the manufacture of the foam of the present invention is selected from organic isocyanates containing multiple isocyanate groups, including: aliphatic isocyanates, such as hexamethylene diisocyanate, more preferably aromatic isocyanates, such as m- and p-phenylene diisocyanate, toluene-2,4- and 2,6-diisocyanate, diphenylmethane-4,4'-diisocyanate, chlorobenzene-2,4-diisocyanate, naphthalene-1,5-diisocyanate, and diphenyl-4,4'-diisocyanate. 4'-Diisocyanates, 4,4'-diisocyanate-3,3'-dimethyldiphenyl, 3-methyldiphenylmethane-4,4'-diisocyanate and diphenyl ether diisocyanate, alicyclic diisocyanates such as cyclohexane-2,4- and 2,3-diisocyanates, 1-methylcyclohexyl-2,4- and 2,6-diisocyanates and mixtures thereof, and bis-(isocyanocyclohexyl-)methane and triisocyanates such as 2,4,6-triisocyanotoluene and 2,4,4'-triisocyanodiphenyl ether.

[0091] In this invention, the expression "at least one isocyanate-containing compound" can also be replaced by "polyisocyanate compound / composition".

[0092] According to embodiments, the at least one isocyanate-containing compound / polyisocyanate composition comprises a mixture of polyisocyanates. For example, a mixture of toluene diisocyanate isomers, such as a commercially available mixture of 2,4- and 2,6-isomers, and a mixture of diisocyanates and higher polyisocyanates produced by the phosgenation of aniline / formaldehyde condensates. Such mixtures are known in the art and include crude phosgenation products comprising a mixture of methylene-bridged polyphenyl polyisocyanates (including diisocyanates, triisocyanates, and higher polyisocyanates) and any phosgenation byproducts.

[0093] Preferred isocyanate-containing / polyisocyanate compositions of the present invention are those in which the polyisocyanate is an aromatic diisocyanate or a higher functional polyisocyanate, particularly crude mixtures of methylene-bridged polyphenyl polyisocyanates containing diisocyanates, triisocyanates, and higher functional polyisocyanates. Methylene-bridged polyphenyl polyisocyanates (e.g., methylene diphenyl diisocyanate, abbreviated as MDI) are well known in the art and have the general formula I, where n is 1 or greater, and in the case of crude mixtures, represents an average value greater than 1. They are prepared by phosgenation of corresponding mixtures of polyamines obtained by the condensation of aniline and formaldehyde.

[0094]

[0095] Other suitable isocyanate-containing compound / polyisocyanate compositions may include: isocyanate-terminated prepolymers prepared by reacting an excess of diisocyanate or a higher-functionality polyisocyanate with a hydroxyl-terminated polyester or a hydroxyl-terminated polyether; and products obtained by reacting an excess of diisocyanate or a higher-functionality polyisocyanate with a monomeric polyol or a mixture of monomeric polyols (such as ethylene glycol, trimethylolpropane, or butanediol). A preferred class of isocyanate-terminated prepolymers is an isocyanate-terminated prepolymer of a crude mixture of methylene-bridged polyphenyl polyisocyanates containing diisocyanate, triisocyanate, and a higher-functionality polyisocyanate.

[0096] Suitable isocyanate reactive compounds used in the methods of this invention include any compounds known in the art for preparing rigid polyurethane or urethane-modified polyisocyanurate foams. Particularly important for the preparation of rigid foams are polyols and mixtures of polyols having the following properties: an average hydroxyl value of 50-1000, preferably 160-1000, particularly 200-700 mg KOH / g, and a hydroxyl functionality of 2-8, particularly 2-6. Suitable polyols have been well described in the prior art and include reaction products of alkyl epoxides (e.g., ethylene oxide and / or propylene oxide) with an initiator containing 2-8 active hydrogen atoms per molecule. Suitable initiators include: polyols such as glycerol, trimethylolpropane, triethylolamine, pentaerythritol, sorbitol, and sucrose; polyamines such as ethylenediamine, toluenediamine (TDA), diaminodiphenylmethane (DADPM), and polymethylene polyphenylene polyamines; and amino alcohols such as ethanolamine and diethanolamine; and mixtures of these initiators. Other suitable polymeric polyols include polyesters obtained by condensing appropriate proportions of diols and higher-functionality polyols with dicarboxylic acids or polycarboxylic acids, DMT waste, or by digesting PET with diols. Further suitable polymeric polyols include hydroxyl-terminated polysulfides, polyamides, polyesteramides, polycarbonates, polyacetals, polyolefins, and polysiloxanes.

[0097] The at least one isocyanate reactive compound preferably contains at least 30 wt%, more preferably at least 60 wt%, of polyester polyol.

[0098] In a particularly preferred embodiment of the invention, almost all of the isocyanate reactive compounds are polyester polyols.

[0099] According to the embodiments, the at least one isocyanate reactive compound is selected from: monohydric alcohols and / or polyhydric alcohols such as diols, high molecular weight polyether polyhydric alcohols and polyester polyhydric alcohols, thiols, carboxylic acids such as polyacids, amines, polyamines, components containing at least one alcohol group and at least one amine group such as polyamine polyhydric alcohols, ureas and amides.

[0100] According to the implementation scheme, the isocyanate reactive component is selected from monohydric alcohols or polyhydric alcohols with an average nominal hydroxyl functionality of 2-8 and an average molecular weight of 32-8000, as well as mixtures of said monohydric alcohols and / or polyhydric alcohols.

[0101] The amount of the polyisocyanate-containing compound and the reactive isocyanate compound to be reacted will depend on the nature of the rigid polyurethane or urethane-modified polyisocyanurate foam to be produced, and will be readily determined by those skilled in the art.

[0102] According to the implementation scheme, the physical blowing agent can be selected from a list including (composed of): isobutylene, dimethyl ether, methylene chloride, acetone, chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs), hydrofluoroolefins (HFO / HCFO), dialkyl ethers, cycloalkylene ethers, ketones, fluorinated ethers, perfluorocarbons, hydrocarbons, and mixtures thereof. The amount of physical blowing agent can vary based on, for example, the intended use and application of the foam product and the desired foam stiffness and density. The amount of physical blowing agent present can be 1-80 parts by weight (pbw) per 100 parts by weight of isocyanate reactive compound (polyol), more preferably 5-60 pbw. If water is used as a chemical blowing agent in the formulation, the amount of water is preferably limited to a maximum of 15 pbw. In other words, the range of water can be 0 to 15 pbw.

[0103] Typically, water or other carbon dioxide-releasing compounds (chemical blowing agents) are used in conjunction with physical blowing agents. When water is used as a chemical co-blowing agent, the typical dosage is in the range of 0.2-5% by weight, preferably 0.5-3% by weight, based on isocyanate reactive compounds.

[0104] The total amount of foaming agent used in the reaction system for producing porous polymer materials will be readily determined by those skilled in the art, but is typically 0.25-25% by weight, based on the total weight of the reaction mixture.

[0105] According to the implementation scheme, in the process of preparing the polyisocyanurate-containing foam of the present invention, one or more urethane catalyst compounds are added to accelerate the reaction to form polyurethane. The urethane catalysts applicable to this document include, but are not limited to: metal salt catalysts, such as organotin compounds, and amine compounds, such as triethylenediamine (TEDA), N-methylimidazolium, 1,2-dimethylimidazolium, N-methylmorpholine, N-ethylmorpholine, triethylamine, N,N'-dimethylpiperazine, 1,3,5-tris(dimethylaminopropyl)hexahydrotriazine, 2,4,6-tris(dimethylaminomethyl)phenol, N-methyldicyclohexylamine, pentamethyldipropylenetriamine, N-methyl-N'-(2-dimethylamino)-ethylpiperazine, tributylamine, pentamethyldiethylenetriamine, hexamethyltriethylenetetramine, heptamethyltetraethylenepentamine, dimethylaminocyclohexylamine, pentamethyldipropylenetriamine, triethanolamine, dimethylethanolamine, bis(dimethylaminoethyl) ether, tris(3-dimethylamino)propylamine, or acid-blocked derivatives thereof, and any mixtures thereof.

[0106] Any compound that catalyzes the trimerization of isocyanates can be used as a trimerization catalyst, such as tertiary amines, triazines, and more preferably metal salts.

[0107] Examples of suitable metal salt trimerization catalysts are alkali metal salts of organic carboxylic acids. Preferred alkali metals are potassium and sodium. And preferred carboxylic acids are acetic acid and 2-ethylhexanoic acid.

[0108] The preferred metal salt trimer catalyst is potassium acetate (available from Air Products for Polycat 46 and from Huntsman for Catalyst LB), with potassium 2-ethylhexanoate (available from Air Products for Dabco K15).

[0109] Two or more different metal salt trimerizing catalysts can be used in the method of the present invention.

[0110] Based on the isocyanate reactive compound, the amount of metal salt trimerizing catalyst used is typically 0.5-5% by weight, preferably about 1-3%.

[0111] Besides this metal salt trimerization catalyst, other types of trimerization catalysts and urethane catalysts can also be used. Examples of these additional catalysts include dimethylcyclohexylamine, triethylamine, pentamethylenediethylenetriamine, tris(dimethylaminopropyl)hydrotriazine (available as Jeffcat TR 90 from Huntsman Performance Chemicals), and dimethylbenzylamine (available as Jeffcat BDMA from Husman Performance Chemicals). They are used in amounts of 0.5 to 8% by weight, based on the isocyanate reactive compound. Typically, the total amount of trimerization catalyst is 0.4 to 4.5% by weight, and the total amount of urethane catalyst is 0.1 to 3.5% by weight, based on the isocyanate reactive compound.

[0112] In addition to the polyisocyanate and polyfunctional isocyanate reactive compositions and the blowing agent, the foam-forming reaction mixture typically contains one or more other auxiliaries or additives that are conventional for formulations used to produce rigid polyurethane and urethane-modified polyisocyanurate foams. These optional additives include: chain extenders such as ethylene glycol or butanediol; crosslinking agents such as low molecular weight polyols such as triethanolamine or glycerol; surfactants; flame retardants such as haloalkyl phosphates such as tris(chloropropyl)phosphate; and fillers such as carbon black.

[0113] In particular, in this invention, additives can be used to further improve the adhesion between the foam and the finishing material. These additives include triethyl phosphate, ethylene glycol and polyethylene glycol, and propylene carbonate, alone or in mixtures thereof.

[0114] In operating the method for manufacturing the rigid foam of the present invention, known one-shot prepolymer or semi-prepolymer techniques can be used in conjunction with conventional mixing methods.

[0115] In many applications, it is convenient to provide components for polyurethane production in premixed formulations based on each of the main polyisocyanate and isocyanate reactive components. In particular, many reaction systems use polyisocyanate reactive compositions that, in addition to one or more polyisocyanate reactive components, also contain main additives such as blowing agents, catalysts, and surfactants.

[0116] Therefore, the present invention also provides a multifunctional isocyanate reactive composition containing an isocyanate reactive component, optionally combined with a foaming agent, other catalysts, surfactants, crosslinking agents, flame retardants and chain extenders.

[0117] The reaction mixture and inorganic filler composition of the present invention can be mixed in a batch (discontinuous) or continuous process.

[0118] For batch mixers, the following types can be used:

[0119] - A change-tank mixer, a vertical batch mixer in which the container can be removed or the stirring blades can be raised after mixing is complete.

[0120] - A helical blade mixer, wherein the mixing element is in the form of a conical or cylindrical helix. The mixer can also be customized to fit the container shape to ensure optimal clearance between the blades and the container wall.

[0121] - A double-arm kneader consists of two counter-rotating blades of different types driven by gears at one or both ends.

[0122] - A screw discharge mixer that can be used in conjunction with a kneader, allowing the screw element to move the material within the reach of the mixing blades.

[0123] - High-intensity mixers, such as the Banbury Mill and Roll Mill.

[0124] For continuous processes, the following types can be used:

[0125] - A single-screw extruder, where the capacity can be determined by length, diameter, and power input.

[0126] - A twin-screw extruder, wherein the screws can be tangential or meshing, rotating in the same direction or in opposite directions.

[0127] - No motion mixers, such as the Kenics static mixer.

[0128] - Mixing head.

[0129] The reaction mixture and inorganic filler composition can be incorporated into a batch or continuous process in a single or multi-step manner. In the second step, before adding the reaction mixture to the inorganic filler, one of the aforementioned mixer types can be used to prepare the reaction mixture. For example, the reaction mixture can also be added to the inorganic filler in a staged process, such as first isocyanate and polyol, then blowing agent, and finally catalyst, or in other order.

[0130] Example

[0131] method

[0132] Density: As described in ISO 845, by dividing mass by volume and expressing in kg / cm³ 3 This indicates that the foam density was measured on the sample.

[0133] Closed-cell content (CCC): The closed-cell content of the foam was measured using an AccuPyc 1330 hydrometer from Micromeritics, in accordance with ASTM D6226-15.

[0134] Calorific value: The calorific value of the foam was measured using a bomb calorimeter according to EN ISO 1716. The foam was ground into a fine powder and used in combination with about 0.7 grams of paraffin wax as a combustion aid.

[0135] Insulation value: The λ value of the foam was measured at 10°C in a TA LaserComp Fox200 apparatus according to ISO 8301.

[0136] Example 1

[0137] Manufacturing of rigid polyisocyanurate insulating foam board according to the present invention filled with 80 wt% barium sulfate.

[0138] The following chemicals, in parts by weight, were used in the manufacture of polyisocyanurate foam boards: Suprasec 5025 (polymeric MDI from Huntsman, NCOv 31%, 21 pbw), Daltolac R251 (polyether polyol from Huntsman, OHv 250, 6.22 pbw), ethylene glycol (OHv 1808, 0.34 pbw), Tegostab B8490 (silicone surfactant from Evonik, OHv 125, 0.175 pbw), water (OHv 6230, 0.082 pbw), catalyst LB (48.2 wt% potassium acetate, from Huntsman, OHv 1097, 0.511 pbw), barite sand 100 / 500 (d90 value in the range of 250-360 μm, from Sachtleben). Bergbau's inorganic packing material has a bulk density of approximately 2.2 g / cm³. 3 It contains 112 pbw (specific volume of approximately 0.45 L / kg) and isopentane (blowing agent, 5.38 pbw). The isocyanate index is 266.

[0139] First, surfactants, polyols, water, chain extenders, and catalysts were mixed together to prepare a polyol blend. Suprasec 5025 and barite sand were premixed separately using a Heidolph mixer at approximately 500-1000 rpm for 60 seconds to form a slurry. Then, the polyol blend and isopentane blowing agent were added to the barite / Suprasec 5025 slurry, and the entire composition was mixed under high shear at approximately 3000 rpm for 20 seconds. Some of the blowing agent evaporated during the final step and therefore could not be fully utilized for foam expansion. The resulting foamed composition was then poured into a 20×20×1cm container.3 The mold is preheated to 100°C and the top and bottom inner surfaces are covered with paper trim, and cured for 30 minutes before demolding.

[0140] Foam board has the following properties: 250kg / m 3 The core density, 75% closed-cell content, λ value of 28.7 mW / mK at 10 °C (measured after 24 hours), and calorific value of 5 MJ / kg (core foam).

[0141] Example 2

[0142] Manufacturing of rigid polyurethane insulating foam board according to the present invention filled with 85 wt% barium sulfate.

[0143] The following chemicals, in parts by weight, were used in the manufacture of polyurethane foam boards: Suprasec 5025 (polymeric MDI from Huntsman, NCOv 31%, 21.72 pbw), Daltolac R411 (polyether polyol from Huntsman, OHv 420, 17.64 pbw), Tegostab B8444 (silicone surfactant from Evonik, 0.44 pbw), water (OHv 6230, 0.1 pbw), DMCHA (N,N-dimethylcyclohexylamine from Huntsman, 0.2 pbw), and precipitated barium sulfate (d90 value < 50 microns, inorganic filler from Acros Organics, bulk density approximately 1.5 g / cm³). 3 40pbw, specific volume of approximately 0.67L / kg), barite sand 500 / 2000 (d90 value in the range of 1-2mm, inorganic filler obtained from Sachtleben Bergbau, bulk density of approximately 2.4g / cm³), 3 The barium sulfate / barite mixture had a bulk density of approximately 3 g / cm³, 186.6 pbw (specific volume of approximately 0.42 L / kg), and Solstice LBA (a blowing agent obtained from Honeywell, 24 pbw). 3 (Specific volume is approximately 0.33 L / kg, d90 value is in the range of 0.5-2 mm). Isocyanate index is 112.

[0144] First, a polyol blend was prepared by mixing a surfactant, polyol, and water. Then, Suprasec 5025, the polyol blend, barite powder, and barite sand were mixed into a slurry using a Heidolph mixer at approximately 500-1000 rpm for 30 seconds. Solstice LBA blowing agent and DMCHA catalyst were added to the Suprasec 5025 / polyol blend / barite slurry, and the entire composition was then mixed for 20 seconds under high shear at approximately 3000 rpm. Some of the blowing agent evaporated during the final step and therefore could not be fully utilized for foam expansion. The resulting foamed composition was then poured into a 20×20×3cm container. 3 The product is placed inside an aluminum mold (preheated at 40°C, with the top and bottom inner surfaces covered with an aluminum finish) and cured for 30 minutes before demolding.

[0145] Foam board has the following properties: 200kg / m 3 The core density, closed-cell content of 83%, λ value of 24.6 mW / mK at 10 °C (measured after 24 hours), and calorific value of 3.3 MJ / kg (core foam).

[0146] Example 3

[0147] Manufacturing of rigid polyisocyanurate insulating foam board according to the present invention filled with 90 wt% barium sulfate.

[0148] The following chemicals, in parts by weight, were used in the manufacture of polyisocyanurate foam boards: Suprasec 5025 (polymeric MDI, NCOv 31%, 10.5 pbw, obtained from Huntsman), Daltolac R251 (polyether polyol, OHv 250, 3.11 pbw, obtained from Huntsman), ethylene glycol (OHv 1808, 0.17 pbw), Tegostab B8490 (silicone surfactant, OHv 125, 0.088 pbw, obtained from Evonik), water (OHv 6230, 0.041 pbw), catalyst LB (48.2 wt% potassium acetate, obtained from Huntsman, OHv 1097, 0.39 pbw), barite sand 500 / 2000 (d90 value in the range of 1-2 mm, obtained from Sachtleben). Bergbau's inorganic packing material has a bulk density of approximately 2.4 g / cm³. 3 The product contains 126 pbw (a volumetric ester of approximately 0.42 L / kg) and Solstice LBA (a blowing agent obtained from Honeywell, 10.3 pbw). The isocyanate index is 266.

[0149] First, surfactants, polyols, water, chain extenders, and catalysts were mixed together to prepare a polyol blend. Suprasec 5025 and barite sand were premixed separately using a Heidolph mixer at approximately 500-1000 rpm for 60 seconds to form a slurry. Then, the polyol blend and Solstice LBA blowing agent were added to the barite / Suprasec 5025 slurry, and the entire composition was mixed under high shear at approximately 3000 rpm for 20 seconds. Some of the blowing agent evaporated during the final step and therefore could not be fully used for foam expansion. The resulting foamed composition was then poured into a 20×20×1cm container. 3 The mold is preheated to 100°C and the top and bottom inner surfaces are covered with paper trim, and cured for 30 minutes before demolding.

[0150] Foam board has the following properties: 325 kg / m³ 3 The core density, 70% closed-cell content, λ value at 10℃ of 27.0 mW / mK (measured after 2 hours), and calorific value of 2.3 MJ / kg (core foam).

[0151] Example 4

[0152] Manufacturing of rigid polyurethane insulating foam board according to the present invention filled with 87 wt% barium sulfate.

[0153] The following chemicals, in parts by weight, were used in the manufacture of polyurethane foam boards: Suprasec 5025 (polymeric MDI from Huntsman, NCOv 31%, 32.58 pbw), Daltolac R411 (polyether polyol from Huntsman, OHv 420, 26.46 pbw), Tegostab B8444 (silicone surfactant from Evonik, 0.66 pbw), water (OHv 6230, 0.15 pbw), DMCHA (N,N-dimethylcyclohexylamine from Huntsman, 0.53 pbw), and precipitated barium sulfate (d90 value < 50 microns, inorganic filler from Acros Organics, bulk density approximately 1.5 g / cm³). 3 60pbw, specific volume of approximately 0.67L / kg), barite sand 500 / 2000 (d90 value in the range of 1-2mm, inorganic filler obtained from Sachtleben Bergbau, bulk density of approximately 2.4g / cm³), 3 The barium sulfate / barite mixture had a bulk density of approximately 3 g / cm³, 342 pbw (specific volume of approximately 0.42 L / kg), and Solstice LBA (a blowing agent obtained from Honeywell, 50 pbw). 3(Specific volume is approximately 0.33 L / kg, d90 value is in the range of 0.5-2 mm). Isocyanate index is 112.

[0154] First, a polyol blend was prepared by mixing a surfactant, polyol, and water. Then, Suprasec 5025, the polyol blend, barite powder, and barite sand were mixed into a slurry using a Heidolph mixer at approximately 500-1000 rpm for 30 seconds. Solstice LBA blowing agent and DMCHA catalyst were added to the Suprasec 5025 / polyol blend / barite slurry, and the entire composition was then mixed for 15 seconds under high shear at approximately 3000 rpm. Some of the blowing agent evaporated during the final step and therefore could not be fully utilized for foam expansion. The resulting foamed composition was then poured into a 20×20×5cm container. 3 The mold is opened and then placed inside an aluminum mold (preheated at 50°C and with the inner surface covered with an aluminum finish), and cured for 30 minutes before demolding.

[0155] Foam board has the following properties: 150kg / m 3 The core density, 80% closed-cell content, λ value at 10℃ of 25.8 mW / mK (measured after 24 hours), and calorific value of 2.9 MJ / kg (core foam).

[0156] Example 5

[0157] Preparation of rigid closed-cell polyurethane insulating foam according to the present invention filled with 83 wt% bismuth oxide (Bi2O3).

[0158] The following chemicals, in parts by weight, are used in the manufacture of polyurethane foam cups: Suprasec 5025 (polymeric MDI from Huntsman, NCOv 31%, 8.15 pbw), Daltolac R411 (polyether polyol from Huntsman, OHv 420, 6.61 pbw), Tegostab B8444 (silicone surfactant from Evonik, 0.16 pbw), water (OHv 6230, 0.036 pbw), Jeffcat DMCHA (N,N-dimethylcyclohexylamine catalyst from Huntsman, 0.175 pbw), and bismuth oxide Bi2O3 fine powder (d90 value < 50 microns, inorganic filler from Jinwang Europe, bulk density approximately 4 g / cm³). 3 It contains 74.8 pbw (specific volume of about 0.25 L / kg) and Solstice LBA (a blowing agent obtained from Honeywell, 5.2 pbw). The isocyanate index is 112.5.

[0159] First, the surfactant, polyol, water, and catalyst were mixed together to prepare a polyol blend. The desired mass of the polyol blend was weighed into a paper cup (450 mL). Bismuth oxide powder was then added on top, followed by isocyanate, and finally Solstice LBA foaming agent. The contents of the cup were thoroughly mixed for 10 seconds at 4000 rpm using a Heidolph mixer. The resulting free-blowing foam was cured at room temperature for 24 hours before further analysis.

[0160] Freely aerated cup foam has the following properties: 230 kg / m³ 3 Its core density and calorific value of 4.19 MJ / kg.

[0161] Comparative example

[0162] Trial production of rigid polyisocyanurate insulating foam board filled with 90 wt% silica quartz sand.

[0163] Example 3 was repeated, except that the barite sand was replaced with silica quartz sand (d90 value < 0.5 mm, inorganic filler obtained from Aldrich, with a bulk density of approximately 1.5 g / cm³). 3 (126 pbw, specific volume approximately 0.67 L / kg) was used instead. Mixing the various formulation components was very difficult because the high volume of silica sand led to uneven filler distribution within the foam, poor expansion, localized collapse, and coarse cell structure. Further characterization could not be performed.

[0164] Throughout this specification, references to "an embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of the invention. Therefore, the appearance of the phrase "in one embodiment" or "in an embodiment" in different places in this specification does not necessarily refer to the same embodiment, but may. Furthermore, it will be clear to those skilled in the art from this disclosure that particular features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Moreover, although some embodiments described herein include some features included in other embodiments but not others, combinations of features from different embodiments are also meant to be within the scope of the invention and form different embodiments, as understood by those skilled in the art.

[0165] The singular forms “a,” “an,” and “the” used in this article include both singular and plural references, unless the context clearly specifies otherwise. For example, “isocyanate group” refers to one or more isocyanate groups.

[0166] As used herein, the terms “containing,” “including,” and “consisting of” are synonymous with “including” or “containing” and are inclusive or open-ended, not excluding additional unlisted members, elements, or method steps. It will be understood that the terms “containing,” “including,” and “consisting of” as used herein include the terms “composed of,” “component,” and “formed by.” This means that, preferably, the aforementioned terms such as “containing,” “including,” “consisting of,” “containing,” “containing,” and “included” can be replaced by “composed of,” “component of,” and “formed by.”

[0167] Throughout this application, the term “about” is used to refer to a numerical value that includes the standard deviation of the error of the apparatus or method used to determine the value.

[0168] The terms “weight%”, “wt%”, “weight percentage”, or “weight percent” used in this article are used interchangeably.

[0169] The numerical ranges listed by endpoints include all integers contained within that range, as well as fractions (where appropriate). For example, when referring to the number of elements, 1-5 may include 1, 2, 3, 4, and when referring to measurement results, it may also include 1.5, 2, 2.75, and 30-3.80. The listing of endpoints also includes the endpoint values ​​themselves (e.g., 1.0 to 5.0 includes both 1.0 and 5.0). Any numerical ranges listed herein are intended to include all subranges contained therein.

[0170] When the article "a" precedes a word, such as in "chemical foaming agent," it also covers more than one given word. Therefore, the article "a" in this text can be replaced by the expression "at least one."

[0171] All references cited in this specification are incorporated herein by reference in their entirety. In particular, the teachings of all references specifically mentioned herein are incorporated by reference.

[0172] Unless otherwise defined, all terms used in disclosing this invention (including technical and scientific terms) have the meanings commonly understood by one of ordinary skill in the art to which this invention pertains. Further guidance, including terminology definitions, is provided to better understand the teachings of this invention.

[0173] Various aspects of the invention are defined in more detail throughout this application. Each aspect thus defined may be combined with any other aspect or plural aspects unless explicitly stated otherwise. In particular, any feature indicated as preferred or advantageous may be combined with any other one or more features indicated as preferred or advantageous. Although preferred embodiments of the invention have been disclosed for illustrative purposes, those skilled in the art will understand that various modifications, additions, or substitutions are possible without departing from the scope and spirit of the invention.

Claims

1. A reaction mixture for producing a foam based on inorganic fillers comprising closed-cell rigid polyurethane or polyisocyanurate (PU or PIR), said foam having a calorific value of less than 6 MJ / kg, as measured according to EN ISO 1716, the reaction mixture comprising: - At least one compound containing a polyisocyanate; - At least one isocyanate reactive compound; - Inorganic filler composition; - At least one physical foaming agent; - Optional surfactants, chemical foaming agents, catalysts, chain extenders, crosslinking agents, antioxidants, flame retardants and / or mixtures thereof; Its features The bulk density of the inorganic filler composition is higher than 2 g / cm³. 3 , The inorganic filler composition is present in an amount of at least 80 wt%, relative to the total weight of the reaction mixture, without regard to the weight of the at least one physical blowing agent; The inorganic filler composition comprises a first inorganic filler selected from bismuth oxide, zirconium (IV), iron (III), barium sulfate, barium carbonate, titanium (IV), aluminum oxide, magnesium oxide, and combinations thereof; and the inorganic filler composition further comprises a material with a bulk density of less than 2 g / cm³. 3 The second inorganic filler is selected from: barium sulfate, aluminum silicate, magnesium silicate, calcium fluoride, ferric sulfate (III), calcium sulfate, calcium carbonate, magnesium sulfate, silicon oxide, sodium carbonate, aluminum hydroxide, magnesium hydroxide, sodium chloride, calcium chloride, perlite and combinations thereof.

2. The reaction mixture according to claim 1, wherein the thermal conductivity of the inorganic filler composition is less than 25 W / mK.

3. The reaction mixture according to claim 2, wherein the first inorganic filler has the following particle size distribution: d90 value in the range of 10-2000 μm.

4. The reaction mixture according to claim 1 or 2, wherein the at least one physical blowing agent is selected from: methylene chloride, chlorofluorocarbons, hydrofluorocarbons, hydrochlorofluorocarbons, hydrofluoroolefins, hydrochlorofluoroolefins, dialkyl ethers, cycloalkylene ethers, ketones, fluorinated ethers, perfluorocarbons, hydrocarbons, and mixtures thereof.

5. The reaction mixture according to claim 1 or 2, wherein the at least one physical foaming agent is selected from isobutylene, dimethyl ether, acetone and mixtures thereof.

6. The reaction mixture according to claim 1 or 2, wherein the at least one polyisocyanate-containing compound is selected from: toluene diisocyanate, methylene diphenyl diisocyanate, polyisocyanate compositions containing methylene diphenyl diisocyanate, and mixtures thereof.

7. The reaction mixture according to claim 1 or 2, wherein the at least one isocyanate reactive compound is a polyol having an average hydroxyl number of 50-1000 and a hydroxyl functionality of 2-8.

8. The reaction mixture according to claim 1 or 2, wherein it comprises a CO2 scavenger.

9. A foam obtained by mixing components of a reaction mixture according to any one of claims 1-8.

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