Kit of parts for producing a foamed binder, in particular a geopolymer foam

Abstract

A kit of parts for producing a foamed binder, in particular a geopolymer foam, is presented and described, comprising a component A and a component B, wherein component A contains at least one filler, at least one aluminosilicate binder, and at least one blowing agent, and component B contains alkali silicate and water. Further described are a method for producing a foamed binder, in particular a geopolymer foam, and the use thereof as an adhesive foam for bonding insulation boards and / or in a plaster system.

Description

[0001]

[0002] March 19, 2026

[0003] Kit of parts for the production of a foamed binder, in particular a geopolymer foam

[0004] The present invention relates to a kit of parts for producing a foamed binder, in particular an adhesive foam for bonding insulation boards in an external thermal insulation composite system (ETICS). In particular, the invention relates to a kit of parts for producing a geopolymer foam, a method for producing a geopolymer foam, a geopolymer foam, the use of a geopolymer foam as an adhesive foam for bonding insulation boards, and the use of a geopolymer foam in a plaster system.

[0005] Efficient insulation is playing an increasingly important role in both new construction and building renovation. Insulation boards are often used, which are attached to the exterior or interior walls of a building. One example of this is wall or ceiling insulation, for instance, in basements. The use of insulation boards creates a thermal insulation composite system (ETICS).

[0006] In addition to efficient building insulation, fire protection is an important safety objective stipulated in the state building code. Currently, classic mineral-based adhesive mortars are primarily used as adhesives for bonding non-combustible external thermal insulation composite systems (ETICS) of fire class A2 according to DIN EN 13501.

[0007] When insulating buildings with external thermal insulation composite systems (ETICS) on both old and new buildings, the insulation boards are typically bonded to the substrate using mineral-based adhesives with a lime / cement binder. The adhesives are delivered to the site of use (construction site or industrial production facility) in bags or silos and mixed with water before application. Mixing can be done manually, with a mixer, or with continuous or forced-action mixers.

[0008] The adhesive is usually applied to the insulation boards by hand, less often mechanically using a pump. The insulation boards are then bonded to the substrate by pressing the bonding surface of the boards into contact with the substrate. The adhesive facilitates contact between the insulation boards and the substrate. Occasionally, the adhesive is sprayed onto the substrate using a pump. In this case, the insulation boards are placed into the wet adhesive bed. The adhesive is then allowed to cure.

[0009] According to the German Association for External Thermal Insulation Composite Systems (ETICS), approximately 30-40 million square meters of ETICS are currently installed annually in Germany alone. This high usage of insulation boards is accompanied by a high demand for adhesives, with an average consumption of 4-6 kg of adhesive per square meter. 2Therefore, approximately 120-240 million kg of adhesive would have to be produced, transported, and usually mixed and processed for each insulation panel.

[0010] This involves a very high logistical and time commitment, which in turn leads to high costs. Furthermore, conventional adhesives require a comparatively long curing time, for example, through drying. Therefore, before any further processing of an ETICS (External Thermal Insulation Composite System), such as sanding, doweling, or reinforcing the insulation layer, waiting times of at least three days are typically required. This reduces the productivity of conventional bonding methods. Especially in times of skilled labor shortages, the complex application and long drying time of the adhesive can thus represent an additional burden for companies and customers.

[0011] In addition, the production of the binders required for the adhesive mortars is extremely energy-intensive, as they are fired at temperatures of 900 to 1200 °C.

[0012] BU / pu 250398WO March 19, 2026. Since fossil fuels such as coal and gas are mostly used to burn raw materials such as limestone for the production of binders such as cement, large quantities of CO2 are consequently emitted into the atmosphere.

[0013] Especially in cement production, sintering at temperatures of 1400 to 1450 °C is necessary, which entails increased energy consumption. Furthermore, CO2 is released from the rock during cement and lime production, representing a significant portion of the carbon dioxide (CC) emissions generated in these industries. For example, approximately 600 kg of CO2 is released during the production of one ton of cement. These process-related CC emissions from the rock are unavoidable.

[0014] Besides bonding insulation boards, mineral compounds, especially mortars, are regularly used for coating wall and ceiling surfaces, for example as plaster. Plaster can be divided into two categories: thick-layer plaster and thin-layer plaster.

[0015] With thick-layer plaster, the material application is usually more than 10 mm.

[0016] Base coat plaster (undercoat) is usually applied directly to the masonry or concrete in thicknesses of 2-3 cm (interiors) and evens out all major irregularities. Pipes and cables are also often embedded in the base coat plaster. The base coat plaster is very strong and serves as a substrate for top coats (decorative plasters).

[0017] Thin-layer plasters are plasters that typically have a material application of less than 10 mm. Topcoats are applied in thin layers of 1-5 mm over the base coat. They serve an aesthetic and / or protective function.

[0018] When several coordinated layers of plaster are applied, for example base coat and top coat, this is referred to as a plaster system.

[0019] Similar to mineral adhesives or adhesive mortars, plaster usually consists of sand and binders such as lime and cement (lime-cement plaster) and / or comprises

[0020] BU / pu 250398WO March 19, 2026 Calcium sulfate (gypsum plaster). The similarity with mineral adhesives for ETICS (External Thermal Insulation Composite Systems) is that the plaster is usually delivered to the site of use (construction site or industrial production) in bags or silos and mixed with water there before application. Here, too, the high logistical effort, both in terms of transport and application (mixing and drying time), can negatively impact productivity. This is primarily due to the high consumption of approximately 14-18 kg of plaster (in powder form) per square meter of wall or ceiling surface with a layer thickness of 10 mm. In addition to considerable resource consumption, this leads, as mentioned at the beginning, to high CO2 emissions that occur during binder production.

[0021] German patent DE 102004060390 describes a method for attaching insulation boards to a substrate using an adhesive foam. The adhesive foam can be a two-component adhesive foam. In particular, the adhesive foam is an organic polyurethane-based adhesive foam. However, a disadvantage is that such organic adhesive foams are flammable. Consequently, such an adhesive foam cannot be used for bonding insulation boards in an external thermal insulation composite system (ETICS) that is to be classified as non-combustible, especially according to DIN EN 13501 in fire class A2. Furthermore, polyurethane adhesive foams are based on isocyanates, which may necessitate special safety precautions during application.

[0022] One object of the invention was therefore to provide a kit of parts for producing a foamed binder, in particular a geopolymer foam, that at least partially overcomes one or more disadvantages of the prior art. The kit of parts is intended to serve as a means of producing a foamed binder, in particular a geopolymer foam, which is especially suitable for bonding insulation boards. At the same time, a foamed binder, in particular a geopolymer foam, produced from the kit of parts should be suitable as a plaster, in particular as a base coat. Furthermore, the kit of parts should be easy to use. In particular, its application should be safe and require no extensive protective measures, such as those required, for example, by a fire extinguisher.

[0023] BU / pu 250398WO March 19, 2026 This kit addresses the physical strain that may be required when handling isocyanate-based polyurethane foams. It is designed to reduce the user's physical workload compared to using conventional adhesive mortars or plasters. Furthermore, it enables the rapid deployment of a geopolymer foam without the need for time-consuming component mixing. This should increase productivity compared to using conventional mineral adhesives and / or plasters, such as mortar or lime-cement plaster. Overall, the kit is intended to have the lowest possible CO2 footprint.

[0024] The foamed binder, particularly the geopolymer foam, should exhibit good adhesion properties and strong bonding strength, enabling the secure bonding of insulation boards, especially within an external thermal insulation composite system (ETICS). The foamed binder, particularly the geopolymer foam, should be universally suitable for bonding a wide variety of insulation materials to various substrates. Furthermore, the foamed binder, particularly the geopolymer foam, should be easy to apply and spread over large areas of walls and ceilings. Advantageously, the foamed binder, particularly the geopolymer foam, should also be able to be applied in greater thicknesses, particularly 10-30 mm, and compensate for uneven surfaces. The cured foamed binder, particularly the cured geopolymer foam, should exhibit high mechanical strength.Furthermore, the use of the foamed binder, particularly the geopolymer foam, is intended to significantly reduce the consumption of conventional mineral adhesives and / or coatings, such as mortar. This should conserve resources. The foamed binder, especially the geopolymer foam, should also be easy to apply precisely and spread evenly. Low-emission application of the foamed binder, especially the geopolymer foam, with rapid curing should be possible. The foamed binder, especially the geopolymer foam, should be suitable for bonding insulation boards, particularly in an ETICS (External Thermal Insulation Composite System) that is non-combustible and / or classified as fire class A2 according to DIN EN 13501. Furthermore, the foamed binder should...

[0025] BU / pu 250398WO 19 March 2026 Binders, in particular geopolymer foam, can be used in a plaster system, especially as a base coat.

[0026] A further object of the present invention is to provide a method for producing a foamed binder, in particular a geopolymer foam, with the described properties. In particular, the method should be fast and efficient. Whenever "geopolymer foam" is mentioned here or elsewhere in this patent application, it also refers to "foamed binder" or "adhesive foam." The term "geopolymer foam" is therefore also considered, independently, to be a disclosure for the terms "foamed binder" and "adhesive foam" and is to be considered synonymous with them.

[0027] All or some of these problems are solved according to the invention by a kit of parts according to claim 1, a method according to claim 41, a geopolymer foam according to claim 48, a use according to claim 49 and a use according to claim 50.

[0028] Advantageous embodiments of the invention are specified in the dependent claims and are explained in detail below.

[0029] The invention provides a kit of parts for the production of a geopolymer foam, comprising a component A and a component B, wherein component A contains filler, aluminum silicate binder and blowing agent, and component B contains alkali silicate and water.

[0030] When geopolymers are mentioned here or elsewhere, they specifically refer to inorganic polymers composed of silicate and aluminum silicate raw materials. Geopolymers are characterized by high strength, chemical resistance, and fire resistance. Furthermore, geopolymers represent an environmentally friendly alternative to traditional building materials such as cement, as less energy is required for the extraction of the raw materials.

[0031] BU / pu 250398WO must be provided by March 19, 2026. Consequently, CO2 emissions can be reduced through the use of geopolymers.

[0032] Surprisingly, it has been found that a geopolymer foam with excellent processing properties can be produced in a particularly simple manner using the kit of parts according to the invention. Components A and B of the kit of parts according to the invention are easy to handle and can be mixed together quickly and easily. The mixing of the two components A and B leads to the rapid formation of the geopolymer foam according to the invention.

[0033] When geopolymer foam is mentioned here or elsewhere, unless otherwise specified, this refers in particular to a fully or partially expanded foam based on geopolymers. The geopolymer foam hardens, especially through polymerization, as a solid, dimensionally stable foam. A solid foam essentially consists of gas-filled cells separated by rigid cell walls.

[0034] The geopolymer foam according to the invention hardens on its own and must be processed within a specific timeframe. Curing by UV radiation is therefore unnecessary. Furthermore, it has been shown that the geopolymer foam according to the invention is particularly user-friendly. The geopolymer foam according to the invention has universal adhesion and can be easily applied to insulation boards and / or the desired substrate and distributed as required.

[0035] Surprisingly, it has been found that the use of water and alkali silicate in component B, in combination with the blowing agent and the aluminum silicate binder in component A, allows for the particularly rapid production of a high-yield geopolymer foam. The rapid expansion of the foam saves time during manufacturing. Furthermore, the foaming process occurs spontaneously, eliminating the need for special foaming equipment.

[0036] BU / pu 250398WO March 19, 2026. The geopolymer foam according to the invention is characterized, in addition to the properties mentioned above, by a high expansion volume. Thus, a particularly efficient geopolymer adhesive or coating agent can be obtained with minimal material input. Tests have shown that material usage can be reduced by at least 50% compared to conventional mortar adhesives used for bonding insulation boards. This reduces physical exertion during processing. At the same time, transport costs can be saved. Furthermore, the reduced material consumption also reduces carbon dioxide emissions, which are generated particularly during the production of mineral binders. Therefore, a particularly resource-efficient geopolymer foam can be produced from the kit of parts according to the invention.Without committing to a specific theory, the surprising effect seems to be explained by the fact that the alkali silicate in component B forms hydroxide ions (OH⁻) which react with the blowing agent, releasing gas. The remaining components of components A and B appear to be finely permeated by the resulting gas bubbles, leading to foam formation. Simultaneously, the alkaline alkali silicate solution activates the aluminosilicate binder. Consequently, the silicate and aluminosilicate components are broken down, and a three-dimensional network structure of aluminosilicates forms through condensation, leading to the curing of the geopolymer foam. The alkali silicate in component B and the specific combination of the blowing agent, filler, and the aluminosilicate binder in component A appear to be particularly responsible for the excellent properties of the geopolymer foam.

[0037] Surprisingly, it has been shown that the filler in component A gives the geopolymer foam particularly advantageous properties. The filler ensures that the foam exhibits high foam stability. Thus, the still-wet foam retains its shape during application, for example, when applied to the side of an insulation board to be bonded and when the bonded side of the insulation board is brought into contact with the substrate. Consequently,

[0038] BU / pu 250398WO March 19, 2026. The foam is not crushed during application. This allows for particularly reliable bonding of insulation boards. Furthermore, the filler contributes significantly to the stability of the cured geopolymer foam. In particular, the filler prevents the formation of cracks in the curing and / or cured geopolymer foam. The geopolymer foam according to the invention exhibits high mechanical stability and is therefore ideally suited for use in a plaster system. In addition, the geopolymer foam according to the invention can be produced more cost-effectively than an organic adhesive foam and, in contrast, offers the advantages of higher mechanical stability and is non-combustible. Furthermore, according to a preferred embodiment of the invention, the geopolymer foam is free of isocyanates.

[0039] This allows the geopolymer foam to be processed easily and safely, especially without the safety precautions required when handling isocyanate-containing components (e.g., polyurethane adhesive foams). Surfactant

[0040] According to a particularly preferred embodiment of the kit of parts according to the invention, component A and / or component B can contain at least one surfactant.

[0041] The use of at least one surfactant in component A and / or component B can increase the stability of the gas- or air-filled pores of the geopolymer foam. As a result of this increased pore stability (foam stability), the fresh geopolymer foam may exhibit a lower risk of collapse. Additionally, the long-term stability of the geopolymer foam can be enhanced, preventing the prepared mineral foam from collapsing even after extended periods of inactivity. In particular, the use of at least one surfactant can promote the formation of a homogeneous pore structure, thereby improving the mechanical properties of both the freshly produced and the dried geopolymer foam. A surfactant can thus be used to effectively prevent the pores of the geopolymer foam from becoming interlocked due to mechanical stress, for example, during application.

[0042] BU / pu 250398WO March 19, 2026 This would lead to larger pores that exhibit lower stability and contribute to an increased risk of geopolymer foam collapse. Finally, the use of at least one surfactant can improve the consistency of the geopolymer foam, making it easier to process, especially to apply and spread.

[0043] In principle, component A and / or component B of the kit of parts according to the invention can contain at least one surfactant from the group consisting of anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, and a mixture thereof. Examples of surfactants are amine oxides, fatty alcohol polyglycol ethers, anionic surfactants such as alkylbenzenesulfonates, alkanesulfonates, alkyl sulfates, fatty alcohol polyglycol ether sulfates, and a mixture thereof.

[0044] Preferably, component A and / or component B of the kit of parts according to the invention can contain an anionic and / or nonionic surfactant. Such a surfactant can be particularly suitable for stabilizing the structure of the geopolymer foam. Furthermore, such a surfactant has proven to be particularly compatible with the other components of components A and B, resulting in the formation of a homogeneous foam structure.

[0045] More preferably, component A and / or component B of the invention may contain a surfactant selected from the group consisting of alkylbenzenesulfonates, alkanesulfonates, alkyl sulfates, olefin sulfonates, fatty alcohol polyglycol ether sulfates, alkyl glycosides, and a mixture thereof. In particular, the surfactant is an olefin sulfonate, an alkyl glycoside, or a mixture thereof. Such a surfactant may be particularly well suited to increasing the pore stability of the geopolymer foam.

[0046] In a particularly preferred embodiment of the invention, component A and / or component B can be a surfactant in the form of Ci4-Ci6-olefin sulfonates and / or Cio-

[0047] BU / pu 250398WO March 19, 2026 contains Ci6-alkyl glycosides. It has been shown that such a surfactant is particularly well suited to increasing the foam volume of the geopolymer foam and effectively preventing its collapse. Furthermore, such a surfactant can be used to stabilize a dispersion of the components of component A and / or B. This can increase the user-friendliness of the kit of parts according to the invention and simultaneously contribute to a homogeneous foam appearance and thus to high stability of the geopolymer foam.

[0048] According to a further preferred embodiment of the kit of parts according to the invention, component A can contain 0.01 wt.% to 15 wt.%, in particular 0.05 wt.% to 10 wt.%, preferably 0.1 wt.% to 8 wt.%, and most preferably 0.5 wt.% to 5 wt.% surfactant, based on the total weight of component A. Such a proportion of surfactant results in particularly good processability of the geopolymer foam. This proportion of surfactant can prevent the pores of the undried geopolymer foam from being crushed or collapsing during processing. A lower amount of surfactant, on the other hand, can lead to reduced stability of the geopolymer foam. Conversely, a higher amount of surfactant can reduce the processability of the geopolymer foam due to excessive flow properties.

[0049] Component A

[0050] filler

[0051] Component A of the kit of parts according to the invention contains one or more fillers.

[0052] When a filler is mentioned here or elsewhere, it refers specifically to a granular or powdery material that is insoluble in the application medium. The filler leads to improved mechanical properties of the

[0053] BU / pu 250398WO March 19, 2026 Geopolymer foam. At the same time, the filler gives the geopolymer foam more volume (fullness).

[0054] Fillers can be of a wide variety of origin. A basic distinction is made between organic and inorganic, natural and synthetic fillers.

[0055] Examples of organic fillers include wood flour, pulp, cork, carbon fibers, cellulose derivatives, textile fibers, ground plastics or elastomers.

[0056] Examples of inorganic fillers include silicates, carbonates, sulfates, oxides and hydroxides, glass fibers, glass beads or broken glass.

[0057] Preferably, the filler in component A can be an inorganic filler, in particular a filler selected from the group consisting of carbonates, silicates, talc, diatomaceous earths, and a mixture thereof, preferably carbonates, silicates, or a mixture thereof. It has been found that such a filler results in excellent processing properties for component A of the kit of parts. At the same time, such a filler can produce a geopolymer foam with particularly high stability. Furthermore, such a filler is non-flammable, thus enabling the production of a geopolymer foam classified as non-combustible.

[0058] According to a further preferred embodiment of the invention, the filler in component A can contain a calcium silicate, in particular wollastonite. Tests have shown that such a filler is particularly suitable for obtaining a mechanically stable geopolymer foam. Such a filler can significantly improve the flexural and compressive strength of the geopolymer and ensure that the geopolymer foam does not develop any cracks, in particular shrinkage cracks, even during or after curing. This allows the structure, insulating properties, and adhesive properties of the geopolymer foam to be retained after curing. Furthermore, such a filler can ensure that the geopolymer foam has a

[0059] BU / pu 250398WO March 19, 2026 exhibits particularly high hardness and stiffness. Therefore, the geopolymer foam can be used as a base coat plaster.

[0060] In a preferred embodiment of the invention, the filler in component A can be rod-shaped wollastonite with a length-to-thickness aspect ratio of 3:1 to 10:1, particularly 3:1 to 6:1, preferably 3:1 to 5:1. Rod-shaped wollastonite with such an aspect ratio has been found to be particularly well-suited for preventing cracking in the dried geopolymer foam. Such an aspect ratio increases both the micro-strength and the impact strength of the geopolymer foam. The resulting increased dimensional stability is particularly relevant for the use of the geopolymer foam as a base coat.

[0061] The filler in component A is more preferably wollastonite, in particular rod-shaped wollastonite, and even more preferably rod-shaped wollastonite with a rod length of 10 pm to 1000 pm, in particular 10 pm to 500 pm, preferably 10 pm to 250 pm or 10 pm to 125 pm, and more preferably 10 pm to 70 pm. Such a rod length is particularly suitable for avoiding cracks, especially shrinkage cracks, which can occur during the curing of the geopolymer foam. A longer rod length, on the other hand, can lead to a more inhomogeneous pore structure and consequently to a lower mechanical strength of the cured geopolymer foam.

[0062] Preferably, the filler in component A of the kit of parts according to the invention can contain 30 wt.% to 90 wt.%, in particular 40 wt.% to 85 wt.%, more preferably 50 wt.% to 80 wt.%, and more preferably 55 wt.% to 75 wt.% calcium silicate, especially wollastonite, based on the total weight of the filler. Such an amount of calcium silicate is particularly suitable for obtaining a stable and universally adhesive geopolymer foam. Lower amounts of calcium silicate, on the other hand, could lead to a geopolymer foam that is more prone to cracking.

[0063] BU / pu 250398WO March 19, 2026, whereas higher amounts of calcium silicate could make the processability of the geopolymer foam more difficult.

[0064] According to a further preferred embodiment of the kit of parts according to the invention, the filler in component A can contain limestone. The limestone can be present in a mixture with the blowing agent, thus simplifying the introduction of the blowing agent into component A. Particularly when only small volumes of blowing agent are required, a mixture of limestone and blowing agent can increase the weighing accuracy. In addition to simplifying the filling of the blowing agent, a mixture of limestone and blowing agent can ensure safety in the large-scale production of component A. In particular, the risk of a dust explosion, which exists when filling the component with only the blowing agent, can be effectively reduced by using limestone.

[0065] More preferably, the filler in component A of the kit of parts according to the invention can contain 0.01 wt.% to 30 wt.%, in particular 0.05 wt.% to 25 wt.%, preferably 0.1 wt.% to 20 wt.%, and more preferably 1 wt.% to 15 wt.%, limestone, based on the total weight of the filler. A higher proportion can lead to reduced stability of the geopolymer foam.

[0066] According to a further preferred embodiment of the kit of parts according to the invention, the filler in component A can be a lightweight filler with a pure density of 5 kg / m³. 3 up to 500 kg / m² 3 , especially of 10 kg / m² 3 up to 400 kg / m² 3 , preferably 20 kg / m² 3 up to 300 kg / m² 3 , further preferably of 50 kg / m 3 up to 200 kg / m² 3, contained. Such a filler serves to reduce the density of component A. As a result of the reduced density, transport energy can be saved. Thus, not only is the transport of the kit of parts according to the invention facilitated, but by saving transport energy, CCh emissions can be reduced, especially compared to conventional mortar. Furthermore, the lightweight filler can contribute to a simplified application of the geopolymer foam, since the

[0067] BU / pu 250398WO March 19, 2026 reduced weight at the same volume means that the effort required, especially when the geopolymer foam is distributed over a large area, can be reduced.

[0068] Preferably, the lightweight filler in component A can be a hollow filler, in particular made of hollow glass spheres. Such a lightweight filler can contribute to a reduced thermal conductivity of the geopolymer foam in addition to reducing its weight. This is particularly advantageous in the field of thermal insulation, for example, when using the geopolymer foam as an adhesive foam in external thermal insulation composite systems (ETICS). In contrast to polymeric or organic lightweight fillers, hollow glass spheres in particular are non-combustible and can therefore contribute to fire protection or the classification of the geopolymer foam as fire class A2.

[0069] In a further preferred embodiment of the invention, the filler in component A can contain 0.01 wt.% to 40 wt.%, in particular 0.1 wt.% to 30 wt.%, preferably 1 wt.% to 25 wt.%, and more preferably 5 wt.% to 20 wt.%, lightweight filler, based on the total weight of the filler in component A. Such a proportion is particularly suitable for effectively reducing the density of component A and thus the weight of the kit of parts according to the invention. At the same time, excellent processing properties and high stability of the dried polymer foam can be achieved with such a proportion. A higher proportion of lightweight filler, on the other hand, could lead to an inhomogeneous formation of the three-dimensional aluminosilicate network, which could result in the dried geopolymer foam exhibiting lower stability.

[0070] In a further preferred embodiment of the invention, component A can contain 1 wt.% to 50 wt.%, in particular 2 wt.% to 40 wt.%, preferably 5 wt.% to 30 wt.%, and more preferably 10 wt.% to 25 wt.%, of filler, based on the total weight of component A. Such a filler content allows for the production of a particularly stable geopolymer foam with advantageous processing properties. Such a geopolymer foam is easy to apply and exhibits high hardness after drying.

[0071] BU / pu 250398WO March 19, 2026 Thus, a plaster and / or a geopolymer adhesive with excellent mechanical properties can be obtained. A higher proportion of filler, however, could lead to an inhomogeneous aluminosilicate network. Consequently, the stability of the dried geopolymer foam could be reduced. Conversely, a lower proportion of filler could reduce the stability of the still-wet geopolymer foam and lead to its collapse during application.

[0072] binder

[0073] Component A of the kit of parts according to the invention contains one or more binders.

[0074] In principle, both inorganic and organic substances can be used as binders. Aluminum silicate binders are among the inorganic binders.

[0075] Examples of binders include bitumen, tar, aluminum phosphates, anhydrides, lime, white cement, potash, water glass, aluminum silicates, alkyl silicates, gypsum, cement, cellulose derivatives, polycondensation resins, polymerization resins or polyaddition resins.

[0076] According to the invention, component A contains at least one aluminum silicate binder.

[0077] In a preferred embodiment of the kit of parts according to the invention, the aluminum silicate binder in component A can be selected from the group consisting of fly ash, brick dust, natural pumice, volcanic ash, slag such as blast furnace slag, metakaolin, and a mixture thereof, in particular metakaolin. Such binders can lead to particularly rapid curing of the geopolymer and to particularly high stability. In particular, such binders can be especially suitable for contact with water and the

[0078] BU / pu 250398WO March 19, 2026 Alkali silicate from component B forms a three-dimensional network structure of aluminosilicates, thus leading to the curing of the geopolymer foam. A geopolymer based on such a binder can exhibit high chemical resistance, particularly to acids, sulfates, chlorides, and other corrosive chemicals. Simultaneously, such a binder can contribute to the geopolymer foam quickly achieving high strength and, in its dried state, exhibiting very good compressive and flexural strength, comparable to or better than that of conventional cement mortars.

[0079] In a further preferred embodiment of the kit of parts according to the invention, the aluminum silicate binder can be metakaolin, in particular highly reactive metakaolin. Such a binder can be particularly suitable for contributing to reduced CCh emissions. The production of metakaolin, which is obtained from kaolinite by calcination, requires significantly lower temperatures (approx. 550-900 °C) than the production of cement clinker (approx. 1400-1450 °C). Consequently, energy and thus CCh emissions can be saved compared to conventional mortars. Furthermore, unlike the production of cement, especially the burning of limestone, the burning of kaolin releases only water, not CO2. The conversion of kaolin to metakaolin essentially follows reaction equation 1.

[0080] Al2(OH)4Si2O5- A12O3■ 2SiO2+ 2H2O [1]

[0081] In comparison, the conversion of calcium carbonate (limestone) to calcium oxide (quicklime) in cement production releases approximately 44% of the mass as CO2-free.

[0082] Furthermore, metakaolin is derived from kaolinite, a common clay mineral that represents a sustainable and readily available raw material source. In contrast, fly ash and slag are based on industrial byproducts whose long-term availability depends on coal and steel production. Metakaolin is also a controlled material that is used in...

[0083] BU / pu 250398WO March 19, 2026 Compared to industrial waste products such as fly ash or slag, metakaolin generally exhibits a higher purity. As a result, a more stable geopolymer foam and / or a geopolymer foam with more predictable material properties can be formed. Furthermore, the use of metakaolin allows for the creation of a geopolymer foam that remains stable even at high temperatures (1000-1200 °C) and is therefore suitable for refractory applications. Finally, metakaolin-based geopolymers tend to exhibit less drying shrinkage and consequently show less cracking than conventional dry mortar. This is particularly advantageous for large-scale applications of the polymer foam, for example, as plaster. Preferably, the binder can be free of fly ash, volcanic ash, natural pumice, or slag. The metakaolin can thus be free of by-products and exhibit consistent quality.

[0084] When highly reactive metakaolin is mentioned here or elsewhere, this refers specifically to metakaolin produced by the thermal activation of kaolin within a specific temperature range. Such metakaolin is characterized by high reactivity and a fine particle size distribution. In particular, the average Stokes diameter of highly reactive metakaolin particles can be approximately 1.3 pm. Highly reactive metakaolin can be particularly well-suited to ensure a rapid reaction with component B, forming a stable geopolymer foam with a homogeneous pore structure.

[0085] More preferably, component A of the kit of parts according to the invention can contain 5 wt.% to 70 wt.%, in particular 5 wt.% to 60 wt.%, preferably 10 wt.% to 55 wt.%, and more preferably 10 wt.% to 45 wt.%, of aluminum silicate binder, based on the total weight of component A. Such a proportion of aluminum silicate binder can result in a particularly well-curing and stable geopolymer foam. Such a proportion of binder can also ensure that no volume shrinkage occurs during the curing of the geopolymer foam. Lower amounts of binder, on the other hand, could lead to the geopolymer foam not curing properly.

[0086] BU / pu 250398WO March 19, 2026 is dimensionally stable and prone to collapse. A higher proportion of aluminum silicate binder can lead to incomplete curing. Furthermore, a higher proportion of aluminum silicate binder could impair adhesion to substrates or insulation boards and the overall workability.

[0087] Component A of the kit of parts according to the invention may also preferably contain an organic, in particular polymeric, binder. The use of such binders allows the characteristic properties of organic and inorganic binders to be combined, resulting in a geopolymer foam with particularly advantageous properties. In this way, a geopolymer foam can be obtained that exhibits high strength and hardness, especially after curing. At the same time, such a geopolymer foam exhibits excellent adhesion to various substrates.

[0088] In a further preferred embodiment of the invention, the organic binder in component A can be a polyester, polyurethane, polyacrylate, copolymer, polybutadiene, polyphenylacetylene, an alkyd resin, or a mixture thereof, in particular a copolymer, preferably a vinyl acetate-ethylene copolymer. Such a binder can bind the components of the geopolymer foam after curing. Furthermore, tests have shown that such a binder can lead to particularly good adhesion to various substrates and insulation materials, especially to expanded polystyrene (EPS).

[0089] Preferably, component A of the kit of parts according to the invention can be 0.1 wt.% to 30 wt.%, based on the total weight of component A, in particular

[0090] The product contains 0.5 wt.% to 20 wt.%, preferably 1 wt.% to 15 wt.%, more preferably 2 wt.% to 10 wt.%, organic binder. Such a proportion of organic binder allows for a particularly good interaction between the aluminum silicate and organic binders, resulting in a geopolymer foam with excellent processing properties.

[0091] BU / pu 250398WO March 19, 2026: A lower proportion of organic binder could result in poorer adhesion of the geopolymer foam. Conversely, a higher proportion of organic binder could lead to a geopolymer foam that is difficult to process and / or foams poorly.

[0092] propellant

[0093] Component A of the kit of parts according to the invention contains propellant.

[0094] When a propellant is mentioned here or elsewhere, it refers in particular to a substance that can be added to a solid substance or a mixture of solids in order to foam it up.

[0095] In principle, the propellant can be a gaseous compound or a gas-evolving solid.

[0096] According to the invention, the blowing agent is a gas-evolving solid. Upon contact with component B, the blowing agent in component A reacts to form a gas, for example hydrogen, which causes the other components of component A and component B to foam up. A geopolymer foam is formed.

[0097] Preferably, the blowing agent in component A of the kit of parts according to the invention can comprise a base metal whose redox couple has a negative standard potential with respect to the standard hydrogen electrode. Such blowing agents are particularly well suited for the production of a geopolymer foam. Due to the mixture of alkali silicate and water, OH' ions are present in component B. The OH' ions then react with the blowing agent, producing hydrogen. The resulting hydrogen causes the expansion of the other components from components A and B, forming a geopolymer foam with a particularly fine and uniform pore structure.

[0098] BU / pu 250398WO March 19, 2026 In a preferred embodiment of the invention, the blowing agent can comprise aluminum powder, zinc powder, iron powder, magnesium powder, or a mixture thereof, particularly aluminum powder. Tests have shown that foam formation can be controlled particularly well with such blowing agents. The time until foam formation occurs can thus be kept short. At the same time, an uncontrolled or excessively rapid reaction is avoided, which could result in an inhomogeneous pore structure and consequently a less stable geopolymer foam.

[0099] Preferably, the blowing agent is in powder form, particularly as a finely dispersed powder. Due to the powder's high surface area, gas, especially hydrogen, can form particularly readily upon contact with component B, leading to the formation of a geopolymer foam.

[0100] The blowing agent preferably has a mean particle size of 1 pm to 100 pm, particularly 10 pm to 90 pm, preferably 20 pm to 80 pm, and more preferably 30 pm to 70 pm, as measured according to DIN 66165. Such a particle size results in a particularly fine distribution of the blowing agent. Consequently, the gas is released in a particularly homogeneous manner, giving the geopolymer foam a uniformly distributed structure of fine pores. This leads to the formation of a stable, non-collapsing geopolymer foam that exhibits high hardness after curing. In contrast, the use of smaller blowing agent particles could lead to an uncontrolled, excessively rapid reaction with component B, resulting in a coarse, inhomogeneous pore structure. Consequently, the stability of the geopolymer foam would be significantly reduced.Conversely, a larger particle size of the blowing agent could lead to slow gas evolution due to the reduced surface area, resulting in slower formation of the geopolymer foam. This could significantly reduce the efficiency of the kit of parts.

[0101] BU / pu 250398WO March 19, 2026 More preferably, component A of the kit of parts according to the invention contains, based on the total weight of component A, 0.01 wt.% to 15 wt.%, in particular 0.05 wt.% to 10 wt.%, more preferably 0.05 wt.% to 5 wt.%, and more preferably 0.1 wt.% to 2 wt.%, blowing agent. Such an amount of blowing agent allows the required amount of gas to be generated to expand the other components of components A and B. Thus, a stable geopolymer foam can be obtained that does not collapse even during drying. A smaller amount of blowing agent, on the other hand, could lead to incomplete foaming of the components. Conversely, a larger amount of blowing agent could lead to an inhomogeneous pore structure with enlarged pores. In addition, a larger amount of blowing agent could lead to significant heat generation due to the exothermic reaction with the hydroxide ions from component B.As a result, the geopolymer foam could partially collapse and would exhibit reduced strength even after curing. This could significantly complicate its application and lead to reduced adhesion of the geopolymer foam to the substrate and / or insulation board, as well as reduced hardness of the cured geopolymer foam.

[0102] In a further preferred embodiment of the invention, component A comprises, based on the total weight of component A, 1 wt.% to 50 wt.%, in particular 2 wt.% to 40 wt.%, preferably 5 wt.% to 30 wt.%, more preferably 10 wt.% to 25 wt.%, filler; 5 wt.% to 70 wt.%, in particular 5 wt.% to 60 wt.%, more preferably 10 wt.% to 55 wt.%, more preferably 10 wt.% to 45 wt.%, aluminosilicate binder; and 0.01 wt.% to 15 wt.%, in particular 0.05 wt.% to 10 wt.%, more preferably 0.05 wt.% to 5 wt.%, more preferably 0.1 wt.% to 2 wt.%, blowing agent.

[0103] Such a composition can lead to a geopolymer foam that is particularly user-friendly and exhibits especially advantageous properties. Thus, a geopolymer foam can be produced quickly and easily with such a composition. Furthermore, a

[0104] BU / pu 250398WO March 19, 2026 Such a composition leads to a geopolymer foam that is suitable both for bonding insulation boards and as a plaster, saving resources compared to conventional plaster or adhesives, such as conventional mortar. With such a composition, a geopolymer foam with particularly good adhesion properties to the substrate and to insulation boards can be obtained from the kit of parts. Thus, such a composition can produce a geopolymer foam suitable for the secure bonding of insulation boards. Furthermore, such a composition can lead to a geopolymer foam that can be used as a plaster with exceptional hardness and advantageous insulating properties.

[0105] Water

[0106] Component A of the kit of parts according to the invention may contain water.

[0107] Component A can generally be in solid form. By adding water, component A can also be in liquid or paste form. This allows component A to be easily filled without generating dust. This can facilitate simple industrial production of component A and simultaneously increase user-friendliness. Furthermore, water in component A can help components A and component B mix more easily, further improving user-friendliness. However, it is also conceivable that component A is free of water or essentially free of water and exists as a solid. In this case, component A can be supplied in bags, for example, as a powder, and mixed with component B, which is in paste or liquid form, at the point of use.

[0108] When the term "pasty" is used here or elsewhere, it refers to a solid-liquid mixture (suspension) with a high solids content.

[0109] BU / pu 250398WO 19 March 2026 indicates. In particular, this refers to a solid-liquid mixture that is no longer flowable but spreadable.

[0110] According to a preferred embodiment, component A contains, based on its total weight, 1 wt.% to 70 wt.%, in particular 10 wt.% to 60 wt.%, preferably 20 wt.% to 55 wt.%, more preferably 30 wt.% to 50 wt.%, and even more preferably 35 wt.% to 50 wt.%, water. Such a proportion allows for particularly user-friendly processing of component A, as mixing with component B is particularly easy.

[0111] Organic filler

[0112] In a further preferred embodiment of the kit of parts according to the invention, component A and / or component B can contain an organic filler, in particular a filler based on plastic fibers. Such a filler can effectively prevent cracks in the dried geopolymer foam and thus increase the mechanical stability of the foam.

[0113] Preferably, the organic filler in component A and / or component B can be a filler based on plastic fibers selected from the group consisting of polyamides, polyesters, polyolefins, polyacrylonitrile, and a mixture thereof, particularly polyacrylonitrile. Such fibers are particularly suitable for increasing the stability of the geopolymer foam due to their high flexibility and ease of processing. The plastic fibers preferably have a length of 1 to 6 mm. Such plastic fibers can contribute to a particularly stable cured geopolymer foam.

[0114] More preferably, the filler in component A, based on the total weight of the filler in component A, can comprise 0.01 wt.% to 30 wt.%, in particular 0.05 wt.% to 20 wt.%, preferably 0.1 wt.% to 15 wt.%, and more preferably 1 wt.% to 10 wt.%, of organic filler, especially a filler based on plastic fibers. It has been shown that such a proportion

[0115] BU / pu 250398WO March 19, 2026 is particularly suitable for increasing the stability of the dried geopolymer foam and effectively preventing cracking. At the same time, such a proportion of organic filler leads to excellent processing properties of the foam, as even the uncured geopolymer foam can exhibit increased dimensional stability. However, a higher proportion of organic filler may result in the geopolymer foam no longer being classified in fire class A2.

[0116] Additive

[0117] Component A and / or component B of the kit of parts according to the invention may further contain one or more additives, in particular rheology additives and / or flow agents.

[0118] Additives can improve the processing properties of component A and / or component B, as well as the properties of the geopolymer foam.

[0119] In particular, component A and / or component B of the kit of parts according to the invention may contain one or more rheology additives.

[0120] Preferably, the rheology additive in component A and / or component B of the invention can be an inorganic and / or an organic thickening agent selected from the group consisting of layered silicates, polyamides, polyurea, cellulose derivatives, polyacrylates, polyurethanes, polysaccharides, cotton fiber, glass fiber, polymer fiber, and a mixture thereof. Such a rheology additive can lead to improved rheological properties and improved processing properties of component A and / or component B and the geopolymer foam.

[0121] In a particularly preferred embodiment of the invention, the rheology additive in component A and / or component B can be selected from the

[0122] BU / pu 250398WO March 19, 2026. Group consisting of xanthan gum, diutan, starch, cellulose, and a mixture thereof, in particular diutan. It has been shown that such a rheology additive can be particularly suitable for adjusting the flow behavior of component A and / or component B and thus contribute to particularly excellent processing properties of component A and / or component B. At the same time, such a rheology additive can improve the robustness of the uncured geopolymer foam.

[0123] More preferably, component A and / or component B of the invention may contain 0.01 wt.% to 10 wt.%, in particular 0.02 wt.% to 5 wt.%, preferably 0.03 wt.% to 3 wt.%, more preferably 0.05 wt.% to 2 wt.%, rheology additive, based on the total weight of the respective component A and / or component B.

[0124] In a further preferred embodiment of the invention, component A and / or component B can contain a flow agent.

[0125] Preferably, the superplasticizer in component A and / or component B can be a superplasticizer based on linine sulfonates, melamine formaldehyde sulfonates, polycarboxylates, or a mixture thereof, in particular a superplasticizer based on polycarboxylates, preferably based on polycarboxylate ethers. Such a superplasticizer can lead to excellent flow behavior of the geopolymer or geopolymer foam produced from components A and B. This improves the processability of the fresh geopolymer foam, thereby increasing user-friendliness, especially in large-area applications. The high water reduction achieved by such a superplasticizer can contribute to improving the mechanical properties of the geopolymer foam.

[0126] Furthermore, component A of the invention can be preferred, in each case based on the total weight of component A, by 0.01 wt.% to 10 wt.%, in particular 0.02 wt.%.

[0127] BU / pu 250398WO 19 March 2026 to 5 wt.%, preferably 0.03 wt.% to 3 wt.%, further preferably 0.05 wt.% to 2 wt.%, containing flow agent.

[0128] Component B

[0129] Alkali silicate

[0130] According to the invention, component B contains at least one alkali silicate. The alkali silicate in component B serves as an alkaline activator to initiate polymerization in conjunction with the aluminosilicate binder in component A and to form a geopolymer. In particular, the alkaline activator, or the alkaline environment, dissolves silicate and aluminate ions from the solid framework of the aluminosilicate binder in component A, and these ions condense to form a three-dimensional network structure of aluminosilicates. Furthermore, the OH' ions formed by the alkali silicate react with the blowing agent in component A, resulting in foam formation.

[0131] Preferably, the alkali silicate is silica, potassium silicate, lithium silicate, sodium silicate, or a mixture thereof, especially potassium silicate. Such an alkali silicate has proven particularly suitable for forming a geopolymer foam with excellent properties. Rapid formation of the geopolymer foam is achieved with such an alkali silicate. Simultaneously, a uniform pore distribution and surface finish, as well as sufficient hardness of the geopolymer foam, can be achieved. In addition, such an alkali silicate can be particularly suitable, in combination with the water from component B and the blowing agent from component A, for ensuring the foaming of the other components of the kit of parts and thus forming a geopolymer foam.

[0132] BU / pu 250398WO March 19, 2026 More preferably, component B of the kit of parts according to the invention can be 1 wt.% to 60 wt.%, in particular 5 wt.% to 50 wt.%, more preferably 10 wt.% to 40 wt.%, more preferably 15 wt.% to 35 wt.%, and even more preferably 20 wt.% to

[0133] Contains 30 wt% alkali silicate. This proportion of alkali silicate ensures the necessary alkalinity for activating the aluminum silicate binder in component A, thus enabling effective formation of geopolymer foam. A lower amount of alkali silicate, on the other hand, could result in an insufficiently high pH value for the alkaline activation of the aluminum silicate binder in component A.

[0134] Consequently, no geopolymer foam or only a geopolymer foam with reduced stability might form. A higher amount of alkali silicate could lead to an increased density of component B, which could result in higher material consumption and simultaneously higher transport costs.

[0135] Water

[0136] According to the invention, component B contains water. The water serves as a protic solvent in which OH' ions can form due to the presence of the alkali silicate. This allows the aluminum silicate binder in component A to be activated. Together with the blowing agent, a gas can be formed that leads to the foaming of the geopolymer foam.

[0137] Preferably, component B of the invention can contain 1 wt.% to 70 wt.%, in particular 10 wt.% to 60 wt.%, preferably 20 wt.% to 55 wt.%, more preferably 30 wt.% to 50 wt.%, and even more preferably 35 wt.% to 50 wt.%, water, based on the total weight of component B. Such an amount of water is particularly well suited for the formation of a geopolymer foam.

[0138] Furthermore, this amount of water is ideal to ensure easy mixing of components A and B. A lower amount of water can lead to a

[0139] BU / pu 250398WO March 19, 2026 may result in worse foam formation, while a higher proportion may lead to a longer drying time for the geopolymer foam.

[0140] According to a further preferred embodiment of the kit of parts according to the invention, component A and component B can each be liquid or pasty independently of one another at room temperature. This allows the components to be connected and / or mixed with each other in a particularly simple and user-friendly manner. At the same time, dust formation can be avoided.

[0141] Brpnsted Base

[0142] In a preferred embodiment of the kit of parts according to the invention, component B may contain Brpnsted-Base.

[0143] The Brensted base is, in particular, a particle (atom, molecule, ion) that is electronegative and has a free electron pair, so that a proton can attach to it (proton acceptor).

[0144] Preferably, the Brpnsted base is a compound that dissociates in water into hydroxide ions (OH⁻) and cations. The resulting hydroxide ions can react with the blowing agent in component A, forming a gas, particularly hydrogen. This gas can cause the other components present in component A and component B to foam. Simultaneously, a Brpnsted base can promote the dissolution of silicate and aluminate ions from the solid framework of the aluminum silicate binder in component A, thus facilitating the formation of a geopolymer or geopolymer foam. Such a reaction is also possible between the components of component A and component B without the addition of a Brpnsted base. However, the Brpnsted base can accelerate the gas formation and dissolution of the aluminum silicate binder.

[0145] BU / pu 250398WO 19 March 2026. Thus, a geopolymer foam can be efficiently provided with the kit of parts, without a long waiting time for foaming.

[0146] Preferably, the Brensted base can be an inorganic base, in particular an inorganic base selected from the group consisting of oxides and / or hydroxides of potassium, sodium, calcium, strontium, magnesium, barium, and a mixture thereof, preferably potassium hydroxide. Such bases can dissociate particularly well in the reaction medium and thus contribute to accelerated foam formation and dissolution of the aluminum silicate binder. Consequently, the waiting time until foam formation occurs can be kept particularly short. A kit of parts containing such a base is therefore suitable for the rapid preparation of a geopolymer foam that can be used for bonding insulation boards and / or as plaster.

[0147] According to a further preferred embodiment of the invention, component B can contain 1 wt.% to 60 wt.%, in particular 10 wt.% to 55 wt.%, preferably 20 wt.% to 50 wt.%, and most preferably 25 wt.% to 40 wt.%, of Brensted base, based on the total weight of component B. Such an amount of Brensted base allows a geopolymer foam to be produced particularly quickly with the kit of parts. With a lower amount of Brensted base, however, the foam formation and the breaking up of the aluminum silicate binder might not be sufficiently accelerated, which could result in longer waiting times for the formation of a geopolymer foam. A higher amount of alkaline base could significantly impair the applicability and processing of the geopolymer foam. Consequently, the geopolymer foam could attack sensitive substrates or only allow application under certain protective measures.

[0148] BU / pu 250398WO March 19, 2026 Container

[0149] According to a particularly practical embodiment, component A and component B of the kit of parts according to the invention can be stored separately in a container with at least two separate reservoirs. Preferably, the container has one reservoir for component A and one reservoir for component B. The container can be made of plastic, metal, or a mixture thereof.

[0150] In particular, the container can be a plastic or metal can or cartridge. This makes the transport and handling of component A and component B of the kit of parts particularly easy.

[0151] For example, the container can be a plastic cartridge or a plastic can. Preferably, the container can be a 2K cartridge or a coaxial cartridge. Such containers can be specifically designed for use with two-component systems and allow for particularly user-friendly operation. In principle, all cartridge and can sizes are conceivable, depending on the intended use.

[0152] Preferably, the container may have a screw cap that is screwed onto an application gun. Alternatively, the container may have an application tube (static mixer). Such a container allows for particularly simple and precise application of the geopolymer foam.

[0153] According to a further embodiment of the invention, component A and component B of the kit of parts according to the invention are stored separately in two different containers. Component A can be in the form of a solid.

[0154] Accordingly, component A can be in a container for solids, in particular a bag, bucket, or silo. Component B is in liquid form. Consequently, component B can be in any container suitable for transporting liquid components.

[0155] BU / pu 250398WO March 19, 2026 Procedure

[0156] The invention further provides a method for producing a geopolymer foam, comprising mixing a component A and a component B, wherein component A comprises filler, aluminum silicate binder and blowing agent, and component B comprises alkali silicate and water.

[0157] The above statements regarding the kit of parts according to the invention apply analogously to the kit of parts, component A and component B. Such a method enables the particularly simple and rapid production of a geopolymer foam that exhibits universal adhesion to the substrate and / or insulation boards, is stable, and forms a hard surface after drying.

[0158] In a further preferred embodiment of the method according to the invention, the mixing can be carried out in a mixing ratio of component A to component B of 0.7 to 1 by weight to 10 to 1 by weight, in particular 0.9 to 1 to 5 to 1 by weight, or 1.5 to 1 to 5 to 1 by weight, preferably 2 to 3.5 to 1 by weight, and even more preferably 2 to 3 to 1 by weight. Such a mixing ratio ensures a particularly efficient combination of the components of component A and component B, resulting in a geopolymer foam with pronounced adhesion properties and high stability, which, in the cured state, exhibits high hardness and compressive strength. Furthermore, excellent application, in particular precise application and easy distribution of the geopolymer foam, can be achieved.Thus, geopolymer foam can serve as a replacement for conventional mortar used for bonding insulation boards or as plaster, thereby contributing to resource conservation. However, an excessively high proportion of component A can result in a geopolymer foam with excessive density, potentially leading to higher material consumption. Furthermore, reduced hardness could occur due to incomplete curing of the geopolymer foam.

[0159] BU / pu 250398WO March 19, 2026 A lower proportion of component A could result in a smaller volume of the geopolymer foam. The adhesion properties and strength of the geopolymer foam, and / or the hardness of the cured geopolymer foam, could also be reduced. Furthermore, a lower proportion of component A can lead to excess amounts of alkali silicate that are not bound within the geopolymer structures. This can migrate to the surface and, together with CO2 from the air, cause carbonate efflorescence. Such efflorescence not only presents an aesthetic problem but can also impair the long-term durability and strength of the geopolymer foam.

[0160] Preferably, the mixture of component A and component B can be expanded. In particular, the expansion occurs through the reaction of the blowing agent in component A with components of component B, forming a blowing gas. The resulting blowing gas can expand the components of the mixture of component A and component B. Because the mixture of components A and B preferably expands through a chemical reaction, a geopolymer foam can be produced in a particularly simple and rapid manner. However, it is also conceivable that the mixture of component A and component B is expanded by adding a foaming agent, for example, surfactants and / or proteins, and / or in a special foaming device.

[0161] More preferably, components A and B can be stored separately in a container with at least two reservoirs. The container can be a can or a cartridge. In particular, the container can be a coaxial cartridge or a 2K cartridge.

[0162] By actuating a mechanism, for example a push button, component A and component B can be mixed in the desired ratio at the can outlet. The contact of the two components results in gas formation, which in turn forms the geopolymer foam according to the invention.

[0163] BU / pu 250398WO March 19, 2026 Such a method can enable particularly fast production and application of the geopolymer foam according to the invention.

[0164] In a further embodiment of the invention, component A is in solid form and component B is in pasty or liquid form. Consequently, the two components can be mixed using a hand mixer or a suitable machine, for example, a continuous mixer. It is also conceivable that a continuous mixer is used in conjunction with a mortar pump or a screw conveyor.

[0165] According to a further preferred embodiment of the inventive method, the volume of the mixture can increase by 20% to 400%, in particular by 40% to 300% or by 60% to 200%, during expansion. Such a volume increase allows for the production of a particularly resource-efficient geopolymer foam. Furthermore, such an expanded geopolymer foam is particularly well suited for use as an adhesive for bonding insulation boards and as plaster. A smaller volume increase, on the other hand, could lead to a geopolymer foam with a higher density, which could make the application and distribution of the geopolymer foam more difficult and lead to higher material consumption. A greater volume increase could lead to a less stable geopolymer foam that tends to collapse. In addition, the cured geopolymer foam could exhibit reduced hardness and compressive strength.

[0166] Preferably, foam formation can occur within 1 to 5 minutes, particularly within 1 to 3 minutes, preferably within 1 to 2 minutes, and even more preferably within one minute, after mixing. This allows for a particularly rapid preparation of the geopolymer foam. Consequently, time and therefore costs can be saved during application. Conversely, a longer time until foam formation could reduce the efficiency of using the geopolymer foam and, in particular, lead to delays in the construction process.

[0167] BU / pu 250398WO March 19, 2026 In a further preferred embodiment of the process according to the invention, the reaction temperature during foam formation can be below 80 °C, in particular below 60 °C, preferably below 40 °C, and more preferably below 30 °C. Such a reaction temperature can be particularly suitable for producing the geopolymer foam according to the invention. Tests have shown that a higher reaction temperature can contribute to the collapse of the geopolymer foam.

[0168] The invention also relates to a geopolymer foam obtained or procured by a method according to the invention.

[0169] What has been said in connection with the kit of parts and the method for producing a geopolymer foam applies accordingly to the geopolymer foam according to the invention.

[0170] According to a preferred embodiment of the inventive method, the cured geopolymer foam has a bulk density of 0.05 g / cm³. 3 up to 1 g / cm² 3 , especially of 0.1 g / cm³ 3 up to 0.8 g / cm³ 3 , preferably of 0.2 g / cm³ 3 up to 0.7 g / cm³ 3 , further preferred from 0.4 g / cm³ 3 up to 0.6 g / cm³ 3 , each determined according to DIN EN 1015-10. This density makes the geopolymer foam particularly easy to work with. Furthermore, such a geopolymer foam can contribute to a particularly resource-efficient bonding of insulation boards and / or to a particularly resource-efficient plaster system. Compared to conventional mineral mortars, material consumption can be significantly reduced due to the lower density. A higher density, on the other hand, could lead to increased material consumption. A lower density could reduce the stability of the cured geopolymer foam.

[0171] According to a further preferred embodiment of the invention, the geopolymer foam can have an adhesive tensile strength of 0.02 N / mm². 2 up to 1.2 N / mm 2 , especially of 0.04 N / mm 2 up to 1.1 N / mm 2 preferably of 0.06 N / mm 2 up to 0.09 N / mm 2 , particularly preferably from 0.07 to 0.9 N / mm 2 , each determined according to DIN EN

[0172] BU / pu 250398WO March 19, 2026 1015-12. Such a high tensile bond strength allows for a particularly strong bond between the geopolymer foam and the substrate. Furthermore, a geopolymer foam with this level of tensile bond strength can be especially suitable for securely bonding insulation boards to the substrate. A lower tensile bond strength could make applying the geopolymer foam to the substrate more difficult and / or cause the insulation boards bonded to the geopolymer foam to detach or slip.

[0173] What has been said in connection with the geopolymer foam according to the invention applies equally to the kit of parts according to the invention and the method according to the invention.

[0174] use

[0175] The geopolymer foam according to the invention is suitable for various uses.

[0176] The invention further relates to the use of a geopolymer foam produced according to a method according to the invention, or a geopolymer foam according to the invention, as an adhesive foam for bonding insulation boards, particularly in external thermal insulation composite systems (ETICS). Such use has the advantage that the bonding of insulation boards, especially in an ETICS, enables the classification of the ETICS as non-combustible, in particular in fire class A2 according to DIN EN 13501. Furthermore, such use has the advantage that material can be saved compared to conventional mineral adhesives, such as mortar. Thus, costs for transport and material can be saved. Such use also enables safe and simple bonding of the insulation boards.

[0177] The invention further relates to the use of a geopolymer foam produced according to a method according to the invention or a

[0178] BU / pu 250398WO March 19, 2026 The invention relates to the use of geopolymer foam in a plaster system, particularly as a base coat in a plaster system. Such use has the advantage that the consumption of conventional mineral coating materials, such as conventional mortar, can be significantly reduced. This saves on material and transport costs. Furthermore, such use can result in a plaster with good insulating properties and thus contribute to improved insulation.

[0179] Examples of implementation

[0180] Example 1:

[0181] A geopolymer foam was produced by mixing the composition of component A shown in Table 1 and the composition of component B shown in Table 2. The quantities used refer to the solid or pure substance content of the components.

[0182] Table 1: Composition of Component A

[0183] Component Quantity [Wt.%]

[0184] Water 43,980

[0185] inorganic filler 13,581

[0186] (Wollastonite / Limestone)

[0187] organic filler (plastic fibers) 0.656

[0188] Lightweight filler (hollow glass spheres) 2.847

[0189] aluminum silicate binder 30,508

[0190] (Metakaolin)

[0191] organic binder 5.905

[0192] Propellant 0.197

[0193] Surfactants 1,933

[0194] Rheology additive 0.131

[0195] Flow agent 0.262

[0196]

[0197] BU / pu 250398WO March 19, 2026 Table 2: Composition of Component B

[0198] Component Quantity [Wt.%]

[0199] Water 43,333

[0200] Alkali silicate (potash water glass) 23,333

[0201] Brensted base (KOH) 33,333

[0202]

[0203] The aforementioned raw materials were dispersed at room temperature and normal pressure for 1-2 minutes using a laboratory dissolver at 1900 rpm.

[0204] Production of a geopolymer foam

[0205] To produce a geopolymer foam, components A and B were combined at room temperature in a mixing ratio of 2.54 to 1 parts by weight, based on the total weight of the mixture. Within approximately 60 seconds of mixing, the mixture began to expand by about 180%, forming a gray-beige foam. According to DIN EN 13501, the foam was classified as non-combustible in fire class A2.

[0206] Use of geopolymer foam as adhesive foam

[0207] Component A and component B were mixed together as described above, resulting in an expanding geopolymer foam. The foam was applied to the bonding surface of an EPS insulation board using a dispensing gun. The bonding surface was then brought into contact with the substrate, so that the adhesive foam was present between the substrate and the bonding surface of the insulation board. The insulation board was then aligned in the desired position, parallel to the substrate. The geopolymer foam expanded only slightly and exhibited good adhesion to both the insulation board and the substrate.

[0208] BU / pu 250398WO March 19, 2026

[0209]

[0210] of in a

[0211] The geopolymer foam was produced as described above and applied in a thick layer (approx. 2-3 cm thick) as a base coat to the masonry to be coated, then spread using a standard trowel. After 24 hours, the applied geopolymer foam was completely dry at 23 °C and fully cured after 28 days. The geopolymer foam exhibited excellent workability. Furthermore, the fully cured base coat met all relevant building physics parameters regarding hardness and moisture permeability. The base coat was also ideally suited for the application of a further coat of plaster.

[0212]

[0213] 2:

[0214] Furthermore, a geopolymer foam was produced by mixing the composition of component A shown in Table 3 and the composition of component B shown in Table 4. The quantities used refer to the solid or pure substance content of the components.

[0215] BU / pu 250398WO March 19, 2026 Table 3: Composition of Component A

[0216] Component Quantity [Wt.%]

[0217] inorganic filler 17,692

[0218] (Wollastonite / Limestone)

[0219] aluminum silicate binder 64,444

[0220] (Metakaolin)

[0221] organic filler (plastic fibers) 0.513

[0222] Lightweight filler 5.128

[0223] Cement 6,838

[0224] organic binder 5,128

[0225] Propellant 0.256

[0226]

[0227] Table 4: Composition of component B

[0228] Component Quantity [Wt.%]

[0229] Water 67,673

[0230] Alkali silicate (potash water glass) 12.935

[0231] Brensted base (KOH) 15,399

[0232] Rheology additive 0.154

[0233] Surfactants 3,839

[0234]

[0235] The composition listed in Table 3 was in solid form, and the composition listed in Table 4 was in liquid form. The raw materials listed in Table 4 were dispersed at room temperature and normal pressure for 1-2 minutes using a laboratory dissolver at 1900 rpm.

[0236] Production of a geopolymer foam

[0237] To produce a geopolymer foam, component A and component B were mixed in a ratio of component A to component B of 0.9 to 1 weight parts, based on the total weight of the mixture, at room temperature.

[0238] BU / pu 250398WO March 19, 2026. The components were brought into contact with the substrate and mixed using a hand mixer. Mixing was carried out in the usual manner, as is known for conventional adhesive mortars, from a solid and a liquid component. Within approximately 60 seconds of mixing components A and B, the mixture began to expand by approximately 180%. A gray-beige foam formed. According to DIN EN 13501, the foam was classified as non-combustible in fire class A2. Due to the high expansion volume and the high proportion of inorganic filler and aluminum silicate binder, the cement content could be kept low compared to conventional adhesive mortars.

[0239] The geopolymer foam was used as an adhesive foam for EPS insulation boards and as a base coat in a plaster system, as described in Example 1. The geopolymer foam exhibited similar properties to the mineral foam produced in Example 1.

[0240] BU / pu 250398WO 19. March 2026

Claims

March 19, 2026 Patent claims 1. Kit of parts for the production of a foamed binder, in particular a geopolymer foam, comprising a component A and a component B, characterized in that the component A at least one filler at least one aluminum silicate binder, at least one blowing agent contains and component B at least one alkali silicate and Water contains.

2. Kit of parts according to claim 1, characterized in that component A and / or component B contains at least one surfactant.

3. Kit of parts according to claim 2, characterized in that the surfactant in component A and / or component B is an anionic, amphoteric, cationic or non-ionic surfactant, in particular an anionic surfactant and / or non-ionic surfactant.

4. Kit of parts according to claim 2 or 3, characterized in that the surfactant in component A and / or component B is selected from the group consisting of alkylbenzenesulfonates, alkanesulfonates, alkyl sulfates, olefin sulfonates, fatty alcohol polyglycol ether sulfates, alkyl glycosides and a mixture thereof, in particular that the surfactant is an olefin sulfonate, alkyl glycoside or a mixture thereof.

5. Kit of parts according to claims 2 to 4, characterized in that the surfactant in component A and / or component B is a Ci4-Ci6 olefin sulfonate and / or a Cio-Ci6 alkyl glycoside.

6. Kit of parts according to claims 2 to 5, characterized in that, that component A contains 0.01 wt.% to 15 wt.%, in particular 0.05 wt.% to 10 wt.%, preferably 0.1 wt.% to 8 wt.%, particularly preferably 0.5 wt.% to 5 wt.%, surfactant, based on the total weight of component A.

7. Kit of parts according to one of the preceding claims, characterized in that component A contains 1 wt.% to 50 wt.%, in particular 2 wt.% to 40 wt.%, preferably 5 wt.% to 30 wt.%, more preferably 10 wt.% to 25 wt.%, filler, based on the total weight of component A.

8. Kit of parts according to one of the preceding claims, characterized in that component A contains 5 wt.% to 70 wt.%, in particular 5 wt.% to 60 wt.%, preferably 10 wt.% to 55 wt.%, more preferably 10 wt.% to 45 wt.%, aluminium silicate binder, based on the total weight of component A.

9. Kit of parts according to one of the preceding claims, characterized in that component A comprises, in each case based on the total weight of component A, 0.01 wt.% to 15 wt.%, in particular 0.05 wt.% to Contains 10 wt.%, preferably 0.05 wt.% to 5 wt.%, further preferably 0.1 wt.% to 2 wt.%, propellant.

10. Kit of parts according to one of the preceding claims, characterized in that the component A, in each case based on the total weight of component A BU / pu 250398WO 19 March 2026 1 wt.% to 50 wt.%, in particular 2 wt.% to 40 wt.%, preferably 5 wt.% to 30 wt.%, further preferably 10 wt.% to 25 wt.%, filler, 5 wt.% to 70 wt.%, in particular 5 wt.% to 60 wt.%, preferably 10 wt.% to 55 wt.%, further preferably 10 wt.% to 45 wt.%, aluminum silicate binder and 0.01 wt.% to 15 wt.%, in particular 0.05 wt.% to 10 wt.%, preferably 0.05 wt.% to 5 wt.%, more preferably 0.1 wt.% to 2 wt.%, propellant, contains.

11. Kit of parts according to one of the preceding claims, characterized in that the filler in component A comprises an inorganic filler, in particular a filler selected from the group consisting of carbonates, silicates, talc, diatomaceous earths and a mixture thereof, preferably of carbonates, silicates or a mixture thereof.

12. Kit of parts according to claim 11, characterized in that the filler in component A contains calcium silicate, in particular wollastonite.

13. Kit of parts according to claim 12, characterized in that the filler in component A contains rod-shaped wollastonite with a length-to-thickness aspect ratio of 3:1 to 10:1, in particular of 3:1 to 6:1, preferably of 3:1 to 5:

1.

14. Kit of parts according to claims 11 to 13, characterized in that the filler in component A, based on the total weight of the filler, contains 30 wt.% to 90 wt.%, in particular 40 wt.% to 85 wt.%, preferably 50 wt.% to 80 wt.%, more preferably 55 wt.% to 75 wt.% calcium silicate, in particular wollastonite. BU / pu 250398WO March 19, 2026 15. Kit of parts according to one of the preceding claims, characterized in that the filler in component A contains limestone.

16. Kit of parts according to claim 15, characterized in that the filler in component A, in each case based on the total weight of the filler in component A, is 0.01 wt.% to 30 wt.%, in particular 0.05 wt.% to Contains 25 wt.%, preferably 0.1 wt.% to 20 wt.%, further preferably 1 wt.% to 15 wt.%, limestone.

17. Kit of parts according to one of the preceding claims, characterized in that the filler in component A is a lightweight filler with a density of 5 kg / m³ 3 up to 500 kg / m² 3 , especially of 10 kg / m² 3 up to 400 kg / m² 3 , preferably 20 kg / m² 3 up to 300 kg / m² 3 , further preferably of 50 kg / m 3 up to 200 kg / m² 3 , contains.

18. Kit of parts according to claim 17, characterized in that the lightweight filler in component A is a hollow filler, in particular made of hollow glass spheres.

19. Kit of parts according to claim 17 or 18, characterized in that the filler in component A, based on the total weight of the filler in component A, contains 0.01 wt.% to 40 wt.%, in particular 0.1 wt.% to 30 wt.%, preferably 1 wt.% to 25 wt.%, more preferably 5 wt.% to 20 wt.%, lightweight filler.

20. Kit of parts according to one of the preceding claims, characterized in that the aluminium silicate binder in component A is selected from the group consisting of fly ash, brick dust, natural pumice, volcanic ash, slag such as blast furnace slag, metakaolin and a mixture thereof, in particular metakaolin. BU / pu 250398WO March 19, 202621. Kit of parts according to claim 20, characterized in that the aluminium silicate binder is metakaolin, in particular highly reactive metakaolin.

22. Kit of parts according to one of the preceding claims, characterized in that the propellant in component A comprises a base metal whose redox couple has a negative standard potential with respect to the normal hydrogen electrode.

23. Kit of parts according to claim 22, characterized in that the propellant comprises aluminium powder, zinc powder, iron powder, magnesium powder or a mixture thereof, in particular aluminium powder.

24. Kit of parts according to one of the preceding claims, characterized in that component A contains 0.1 wt.% to 30 wt.%, in particular 0.5 wt.% to 20 wt.%, preferably 1 wt.% to 15 wt.%, more preferably 2 wt.% to 10 wt.%, organic binder, based on the total weight of component A.

25. Kit of parts according to claim 24, characterized in that the organic binder in component A is a polyester, polyurethane, polyacrylate copolymer, polybutadiene, polyphenylacetylene, an alkyd resin or a mixture thereof, in particular a copolymer, preferably a vinyl acetate-ethylene copolymer.

26. Kit of parts according to one of the preceding claims, characterized in that component A and / or component B contains an organic filler, in particular a filler based on plastic fibers.

27. Kit of parts according to claim 26, characterized in that the organic filler is a filler based on plastic fibers selected from the group BU / pu 250398WO 19 March 2026 consisting of polyamides, polyesters, polyolefins, polyacrylonitrile and a mixture thereof, in particular polyacrylonitrile.

28. Kit of parts according to claim 26 or 27, characterized in that the filler in component A, based on the total weight of the filler in component A, comprises 0.01 wt.% to 30 wt.%, in particular 0.05 wt.% to 20 wt.%, preferably 0.1 wt.% to 15 wt.%, more preferably 1 wt.% to 10 wt.%, organic filler, in particular a filler based on plastic fibers.

29. Kit of parts according to one of the preceding claims, characterized in that the component A and / or component B contains a rheology additive, in particular an inorganic and / or an organic thickening agent selected from the group consisting of layered silicates, polyamides, polyurea, cellulose derivatives, polyacrylates, polyurethanes, polysaccharides, cotton fiber, glass fiber, polymer fiber and a mixture thereof.

30. Kit of parts according to claim 29, characterized in that the rheology additive in component A and / or component B is selected from the group consisting of xanthan gum, diutan, starch, cellulose and a mixture thereof, in particular diutan.

31. Kit of parts according to one of the preceding claims, characterized in that component A and / or component B, each based on the total weight of the respective component A and / or component B, contains 0.01 wt.% to 10 wt.%, in particular 0.02 wt.% to 5 wt.%, preferably 0.03 wt.% to 3 wt.%, more preferably 0.05 wt.% to 2 wt.%, rheology additive. BU / pu 250398WO March 19, 202632. Kit of parts according to one of the preceding claims, characterized in that component A and / or component B contains a superplasticizer, in particular a superplasticizer based on linine sulfonates, melamine formaldehyde sulfonates, polycarboxylates or a mixture thereof, preferably a superplasticizer based on polycarboxylates, more preferably based on polycarboxylate ethers.

33. Kit of parts according to claim 32, characterized in that component A contains 0.01 wt.% to 10 wt.%, in particular 0.02 wt.% to 5 wt.%, preferably 0.03 wt.% to 3 wt.%, more preferably 0.05 wt.% to 2 wt.%, flow agent, based on the total weight of component A.

34. Kit of parts according to one of the preceding claims, characterized in that each component A contains 1 wt.% to 70 wt.%, in particular 10 wt.% to 60 wt.%, preferably 20 wt.% to 55 wt.%, more preferably 30 wt.% to 50 wt.%, water, based on the total weight of component A.

35. Kit of parts according to one of the preceding claims, characterized in that component A and component B are each liquid or pasty independently of each other at room temperature.

36. Kit of parts according to one of the preceding claims, characterized in that each component B contains, based on the total weight of component B, 1 wt.% to 60 wt.%, in particular 5 wt.% to 50 wt.%, preferably 10 wt.% to 40 wt.%, more preferably 15 wt.% to 35 wt.%, alkali silicate.

37. Kit of parts according to claim 36, characterized in that the alkali silicate is silica, potassium silicate, lithium silicate, sodium silicate or a mixture thereof, in particular potassium silicate. BU / pu 250398WO March 19, 202638. Kit of parts according to one of the preceding claims, characterized in that components B each contain 1 wt.% to 70 wt.%, in particular 10 wt.% to 60 wt.%, preferably 20 wt.% to 55 wt.%, more preferably 30 wt.% to 50 wt.%, water, based on the total weight of component B.

39. Kit of parts according to one of the preceding claims, characterized in that component B comprises, in each case based on the total weight of component B, 1 wt.% to 60 wt.%, in particular 10 wt.% to 55 wt.%, preferably 20 wt.% to 50 wt.%, particularly preferably 25 wt.% to Contains 40 wt.% Brpnsted base.

40. Kit of parts according to claim 39, characterized in that the Brensted base is an inorganic base, in particular an inorganic base selected from the group consisting of oxides and / or hydroxides of potassium, sodium, calcium, strontium, magnesium, barium and a mixture thereof, preferably potassium hydroxide.

41. A method for producing a foamed binder, in particular a geopolymer foam, comprising mixing a component A and a component B, characterized in that component A comprises filler, aluminum silicate binder and blowing agent and component B comprises alkali silicate and water.

42. Method for producing a foamed binder, in particular a geopolymer foam, characterized in that component A and / or component B is defined as in any one of claims 2 to 40.

43. Method according to claim 41 or 42, characterized in that the mixing is carried out in a mixing ratio of component A to component B of 0.7 to 1 weight parts to 10 to 1 weight parts, BU / pu 250398WO March 19, 2026, in particular 0.9 to 1 weight shares up to 5 to 1 weight shares, preferably from 2 to 1 weight shares up to 3.5 to 1 weight shares.

44. Method according to claims 41 to 43, characterized in that the mixture of component A and component B is expanded.

45. Method according to claims 41 to 44, characterized in that during expansion the volume of the mixture increases by 20 to 400%, in particular by 40 to 300% or by 60 to 200%.

46. ​​Method according to claims 41 to 45, characterized in that the foaming occurs within 1 to 5 minutes, in particular within 1 to 3 minutes, preferably within 1 to 2 minutes, more preferably within one minute, after mixing.

47. Method according to one of claims 41 to 46, characterized in that the reaction temperature during foam formation is below 80 °C, in particular below 60 °C, preferably below 40 °C, more preferably below 30 °C.

48. Foamed binder, in particular geopolymer foam, obtained or obtainable by a method according to claims 41 to 47.

49. Use of a foamed binder produced according to a method according to claims 41 to 47, in particular a geopolymer foam, or of a foamed binder, in particular a geopolymer foam, according to claim 48 as an adhesive foam for bonding insulation boards, in particular in external thermal insulation composite systems.

50. Use of a foamed binder produced according to a method according to claims 41 to 47, in particular a geopolymer foam, or of a foamed binder, in particular a geopolymer foam, according to BU / pu 250398WO 19 March 2026 Claim 48 in a plaster system, in particular as a base coat in a plaster system. BU / pu 250398WO March 19, 2026

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