FOAMING AGENT AND METHOD FOR FOAMING AND STABILIZING FOAMS FOR AIR-ENCLOSED BUILDING MATERIALS

Description

[0001] The invention relates to a foaming agent for foaming a binder paste or a building material slurry for producing air-entrained building material, the use of this foaming agent for stabilizing a foam for air-entrained building material, processes for producing an air-entrained building material, and air-entrained building materials and building products obtainable by the processes.

[0002] The strength of hydraulically setting building materials is provided by the type, quantity, and quality of the binder used, and is enhanced or adjusted as required by additives and aggregates. A binder paste is made from binder and water. Components of the binder react with the water and set. In some cases, this directly results in the building material, e.g., in the case of gypsum filler and certain lime plasters. In this case, the binder paste directly forms the building material slurry. In other cases, an aggregate, usually gravel, sand, ash, fibers, or slag, and / or additives in the form of building material additives such as superplasticizers, accelerators, or retarders, are added to the binder paste to impart the desired properties. The water-based binder paste with aggregate and additives is referred to below as the building material slurry. This viscous slurry sets to form the finished building product.

[0003] Construction products within the meaning of this description may be gypsum, concrete, lime, or mixtures thereof. Binders include slaked lime, natural and FGD gypsum, and various types of cement, preferably Portland cement or high-alumina cement. The designation "gypsum, lime," and cement typically also includes binders that contain a minor amount of another binder or additional powdered mineral components, e.g., inorganic oxides (Mg, Si, Fe).

[0004] The rheology and setting behavior of building material slurries, particularly for concrete and gypsum, have been extensively studied. However, due to the numerous possible combinations, they depend on a large number of factors and are therefore not conclusively examined. The number of combinations with aggregates and additives complicates conclusive studies. Furthermore, there is often a significant dependence on processing temperature and pressure. Furthermore, building materials are natural substances subject to natural fluctuations, which is why variations in results are possible even with identical mixtures.

[0005] Lighter and better heat and cold insulating building materials have long been known as so-called lightweight or porous building materials. These are lower in density due to air inclusions or the addition of lightweight aggregates such as perlite, expanded clay, pumice, or cellulose. The disadvantages compared to air inclusions are the often high price of the aggregates, their limited availability, and their often negative effect on the insulating or soundproofing properties of the building material.

[0006] EP 0 568 752 A1 discloses a lightweight gypsum produced by adding a mineral, porous filler, preferably perlite, to a gypsum building material. The pores of the filler material result in a building material with a lower, adjustable density than solid gypsum.

[0007] Gypsums have a wide range of industrial uses, including as building and modeling materials, as insulation materials, as impression materials, and for medical purposes. Gypsums often possess desirable processing properties, such as good formability and modelability before setting, and good reworkability and sandability after setting. They offer the desired degree of strength for many purposes, are relatively inexpensive, and readily available. Chemically, they are calcium sulfates, which can be naturally occurring or synthetically produced in various modifications. The dihydrate (CaSO4·2H2O) releases water of crystallization when heated, first converting into a hemihydrate and later into an anhydrite. At least partially dehydrated gypsum molds can reabsorb water and recrystallize in the process. Gypsum that is not fully hydrated can therefore set by absorbing water.

[0008] Today's requirements in the construction industry demand that building materials be lightweight (low transport costs, easy processing), have good heat and cold insulation values ​​(energy savings), and have improved sound insulation (living comfort, health). The basis for this are lightweight building materials from which these products can be manufactured. To reduce the weight of established building materials and thus maintain the required properties, air pores can be permanently added to the building material slurry during the manufacturing process. The binders used are thus endowed with properties or combinations of properties that enable products to be manufactured that are not currently available on the market. Established products can be significantly improved or endowed with new properties with the help of a stable pore structure. In addition to use in industrial production, it is desirable to be able to manufacture and install the material on site.The foamed mash should be stable and processable, producible in the desired density and conveyable and processable without loss of density.

[0009] DE 20 56 255 A1 discloses a foaming agent for gypsum and cement compounds, in which alpha-olefin sulfonates and / or certain alkali, ammonium, or ethanolamine salts of sulfuric acid esters of oxyalkylated alcohols are used as surfactants. Furthermore, additional stabilizers, particularly fatty alcohols, and glycols can be added as antifreeze agents. This stabilization is partially sufficient for building material slurries if they are subjected to little or no pressure, are applied only at low installation heights, or if small temperature fluctuations are expected at the installation point. However, the pore structure in the building material adhesive can fail under increased pressure, greater installation heights, or significantly elevated temperatures at the installation point.

[0010] To produce (porous) lightweight building materials, the binder paste or building material slurry is mixed with a foam. The air pores of the foam are retained, and the volume of the slurry is increased by the volume of the foam. Since foam has a low inherent weight, this reduces the density / weight. The result is foamed binder paste or foamed building material slurry. This foamed building material slurry cures through drying / curing to form a lightweight building material or porous lightweight building material that contains the air pores of the foam.

[0011] From US 2006 / 0278128 A1, it is known to use superplasticizers such as polycarboxylate ethers in the production of foamed plasterboard to achieve pores of a specific desired (average) pore size by "merging" small pores into "medium" pores. The merged pores remain until the gypsum glue stiffens (approximately three minutes), producing a stable foamed plasterboard. The foam required for this is more stable than the pure foamed surfactant, but still unstable, since small pores must continue to merge into "medium" air pores.

[0012] The creation of such "medium-sized" pores is also the goal and subject of US 2009 / 0169864 A1. Here, a mixture of two surfactants, one of which is ethoxylated, is used to create a pore structure that is more stable than that of non-ethoxylated surfactants alone, but not so stable that the small pores created during foaming are retained. Object of the invention

[0013] Foaming agents for gypsum and concrete have not yet been satisfactory for all applications, as the foamed building material slurry can collapse spontaneously or the set density cannot be maintained during pumping, pouring, or transport. Unstable air voids burst, reducing volume and increasing density.

[0014] Stabilizers added to stabilize the foam and thus improve the properties of the foam and thus of the air-entrained building material often promise more favorable properties, but upon closer examination, they rarely deliver. State-of-the-art stabilizers do not deliver the desired effects, especially under challenging conditions (extreme temperatures, temperature fluctuations, temperatures unsuitable for the foaming agent, strong mechanical impacts on the material before it reaches the installation point or at the installation point itself).

[0015] The object of the invention is to eliminate the disadvantages of the prior art with regard to foam stability and to provide a foaming agent for the production of air-entrained building materials and, made therefrom, an air-entrained building product, or generally a porous lightweight construction, filling, and insulating material, wherein the not yet set, foamed building material slurry remains stable under processing conditions and during the drying process. Furthermore, it is an object of the invention to provide a method that facilitates the handling of the foaming agent and thus the production of building material slurry and air-entrained building materials.

[0016] In this sense, the foaming agent can also be regarded as a pore former for the set building material.

[0017] Furthermore, the foamed slurry should remain essentially volume-stable under mechanical stress, i.e., during pumping, lowering, or at installation heights of more than 10 cm, without developing inhomogeneities. When conveyed using suitable pumps (especially peristaltic and screw pumps), the construction foam should reach the installation point without significant loss of density, remain stable there until complete setting, and develop no instabilities or inhomogeneities.

[0018] Additionally, the foamed mash should not change its build-up height during the drying, setting, or hydration process. If the material is applied at a height of 40 cm, this height should still be maintained after setting.

[0019] The process for producing lightweight gypsum and gypsum foams is intended to be applicable to all pure gypsum, construction gypsum, FGD gypsum (alpha and beta hemihydrates), and gypsum mixtures. In addition, other powdered mineral building materials, including lime, limestone, cement, high-alumina cement, and / or silicic acid-containing building materials, even in mixtures with gypsum and, if necessary, other aggregates, can be processed, i.e., foamed, using the process.

[0020] The process for producing lightweight concrete should be applicable to Portland cement of all available varieties and commercial grades, including those already factory-mixed with additives and / or aggregates. All known additives and powdered aggregates, particularly mineral building materials, including gypsum, gravel, limestone, high-alumina cement, silicates, and / or siliceous building materials, can be used as aggregates for pure Portland cement. Summary of the invention

[0021] The task is solved by a foaming agent of the type mentioned above, which consists of the following: a) 0.1 to 65.0 wt.%, preferably 4.0 to 25.0 wt.%, particularly preferably 12.0 to 17.0 wt.%, of ionic, preferably anionic, foam-forming surfactant; b) 0.05 to 9.0 wt.%, preferably 1.0 to 7.0 wt.%, particularly preferably 2.0 to 6.0 wt.%, of at least one compound ELF-HG which is solid at room temperature and is selected from the group consisting of ethoxylated fatty alcohols having an alcohol chain in the carbon backbone with at least 12 carbon atoms, ethoxylated natural resins, ethoxylated artificial resins and ethoxylated glycols; c) 0.1 to 7.0 wt.%, particularly preferably 2.0 to 6.0 wt.% of fatty alcohol with a chain length of C10 to C18, preferably of C12 to C16; d) 0.1 to 60.0 wt.%, preferably 10.0 to 55.0 wt.%, particularly preferably 15.0 to 50.0 wt.% of solvent selected from the group consisting of vicinal diols having 1 to 6 C atoms, diethylene glycol, triethylene glycol and diethylene glycol ethers; e) 0 to 20 wt.%-% organic additives; f) 0 to 20 wt.% pH regulators; g) 0 to 99.75 wt.%, preferably 20.0 to 85.0 wt.%, particularly preferably 15.0 to 75.0 wt.%, water, . the mixture totaling 100% by weight.

[0022] "Consists of..." or "consisting of..." is to be understood as exhaustive in the context of the present invention, i.e. in addition to the compounds mentioned, no other substances are included which contribute to the effect of the agent.

[0023] The object is further achieved by the use of the foaming agent described above for stabilizing a foam from which the foaming agent is used for producing air-entrained building materials, in particular filling, lightweight construction and insulation materials.

[0024] The invention provides a novel foaming agent that is significantly more stabilized than those known from the prior art. The service life of foamed binder pastes or building material slurries obtained with the foaming agent or pore-forming agent is excellent, even at low and high temperatures, under pressure, and under mechanical stress. The foamed slurries are pumpable as such, and their volume is retained, allowing them to cure into air-entrained filling, lightweight construction, and insulating materials during conventional treatment in construction or in molded article production. This generally applies to hydraulically curing building materials. The novel foaming agent can be used in combination with a wide variety of binders and binder mixtures, including gypsum, lime, and cement.

[0025] Within the scope of the invention, it was found that foams made from a foaming agent for the production of air-entrained filling, lightweight construction, and insulation materials—namely, foamed binder pastes and foamed building material slurries—are surprisingly excellently stabilized by adding at least one ethoxylated compound that is solid at room temperature, selected from the group consisting of ethoxylated long-chain fatty alcohols, ethoxylated natural resins, ethoxylated synthetic resins, and ethoxylated glycols. In particular, foaming agents based on ionic foaming surfactants are optimally stabilized by the compounds according to the invention.

[0026] Ethoxylation is the addition of ethylene oxide (oxirane) to compounds. The degree of ethoxylation refers to the amount of ethylene oxide bound to a compound. The degree of ethoxylation can range from slightly ethoxylated (1-4 mol of ethylene oxide per mol of compound to be ethoxylated) to highly ethoxylated (120+ mol). The degree of ethoxylation influences the water solubility of the substance. Stearyl alcohol (C-18 fatty alcohol), for example, is not water-soluble. Through ethoxylation, the stearyl alcohol becomes accessible to an aqueous solution, in this case the foaming agent, while retaining its ability to support a pore-forming agent. Optimal water solubility does not always correlate with the highest degree of ethoxylation.

[0027] "Water-soluble" in the context of the present invention means that the ethoxylated compound is completely dissolved in the unfoamed pore-forming agent, although clouding may occur depending on the material and temperature. Any clouding does not negatively affect the functionality or effectiveness of the pore-forming agent.

[0028] "Long-chain" in the context of the present invention means that the ethoxylated fatty alcohol has at least 12 carbon atoms in the carbon skeleton of the alcohol backbone. Fatty alcohols with backbone lengths of 12 to 22 carbon atoms are particularly suitable for the present invention, preferably with backbone lengths of 14 to 20 carbon atoms, and most preferably with backbone lengths of 14 to 18 carbon atoms.

[0029] ELF-HG compounds are known as base materials for cleaning agents or cosmetics and can be modified in a wide variety of ways, depending on the type of polymer or fatty alcohol to be ethoxylated and its degree of ethoxylation, in order to optimize their effectiveness for the application. Such ELF-HG compounds consist of a lipophilic part and a hydrophilic part, in this case ethylene oxide. The hydrophilic part makes previously insoluble substances water-soluble without losing certain basic properties of the starting material. For example, a hydrophobic long-chain fatty alcohol becomes hydrophilic and can be added to the foaming agent as a stabilizer, where it exerts its supporting effect without losing its lipophilic properties.

[0030] It is important that the ethoxylated compound is solid at room temperature. Compounds that are liquid at room temperature do not exhibit the desired stabilization.

[0031] Preferably, the degree of ethoxylation of the at least one ELF-HG compound in the case of long-chain fatty alcohols is from 3 to 150, preferably from 25 to 90, particularly preferably from 50. For applications at low temperatures below 30°C, degrees of ethoxylation of from 50 to 80 and very preferably from 60 are particularly suitable. In the case of high temperatures, a degree of ethoxylation between 10 and 30, preferably from 15 to 25, is particularly suitable. To cover a broad temperature range, degrees of ethoxylation of from 25 to 60 are particularly suitable.

[0032] In the case of natural or synthetic resins, the degree of ethoxylation is preferably 3 to 120, preferably 10 to 80, particularly preferably 30 to 60. In the case of polyethylene glycols, the degree of ethoxylation is preferably in the range of 3 to 120, preferably 5 to 60, particularly preferably 15 to 50.

[0033] The foaming agents stabilized by the use according to the invention are those that have long been known as alternatives to porous fillers, but have only been used practically in isolated cases, namely foaming agents based on ionic foaming surfactants in aqueous organic solvents, generally in water-alcohol mixtures, especially water-glycol mixtures. It is essential that highly foam-forming surfactants are used as surfactants. The foam produced with them is often additionally strengthened with proppant agents, such as fatty alcohols. From a chain length of 12 carbon atoms, the fatty alcohol becomes so hydrophobic that its addition to the foaming agent is only possible with the assistance of a solvent. Despite the presence of a solvent, there is a risk that the fatty alcohols used will separate and lose their effectiveness as proppant agents.In general, the longer the carbon chain, the more stable the foam. However, chain lengths of C-14 and above preclude use in pore-forming agents, as the material is hydrophobic and cannot be integrated into the foaming agent. ELF-HGs are hydrophilic and possess a sufficient chain length of carbon atoms to support the foaming agent beyond what is known so far.

[0034] The ELF-HG content in the foaming agent not yet combined with a building material component is preferably at least 0.05 wt.% and preferably not more than 9.0 wt.%, but may be higher depending on the ethoxylated ELF-HG. Foaming agents can be dosed at high levels, but overdosing reduces foam stability and increases the consumption of foaming agent required for foam production. Higher concentrations often no longer achieve improved stabilization and are not economically viable.

[0035] Commercially available ELF-HGs are available in solid or wax-like form, depending on the temperature. The term "solid" as used in the claims includes the wax-like form. The weight percentages for addition to the foaming agent refer to the ELF-HG content specified by the manufacturer for the product (= substance content or solid content).

[0036] The ratio of ELF-HG to surfactant is preferably between 1:12 and 1:1, preferably between 1:12 and 1:6 and particularly preferably 1:3.

[0037] The ELF-HG is preferably used to stabilize the foaming agent foam in combination with at least one fatty alcohol, which is described in more detail below. The ratio of fatty alcohol to ELF-HG is preferably from 5:1 to 1:4. A ratio of 1:1 is particularly preferred. Fatty alcohols with a chain length of 12 to 16 carbon atoms are particularly suitable. It has proven particularly effective to use a mixture of C12 and C14 fatty alcohols. The weight ratio of C12 to C14 is preferably between 4:1 and 1:1, most preferably 3:1.

[0038] In the present invention, "a ratio of 3:1" means that 3 parts of one substance contains 1 part of the other substance, so 100% is 75% of one substance and 25% of the other substance. The same applies to other ratios.

[0039] Furthermore, it is particularly preferred if at least one solvent selected from the group of vicinal diols having 1 to 6 C atoms, diethylene glycol, triethylene glycol and diethylene glycol ether is additionally present in the compound, wherein the ratio of ELF-HG to solvent can range from 1:2 to 1:16 and is preferably 1:9.

[0040] The ratio of surfactant to fatty alcohol is preferably from 1:1 to 12:1, particularly preferably 3:1. The ratio of surfactant to solvent is preferably from 5:1 to 1:12, particularly preferably 1:3. Finally, the ratio of fatty alcohol to solvent is preferably from 2:1 to 1:16, particularly preferably 1:9.

[0041] The generic foaming agent belonging to the invention in this context consists of the basic components mentioned, whereby the ratios of the individual components refer both to ready-to-use, diluted foaming agent and to concentrates which must be diluted beforehand.

[0042] The aqueous-organic solvent content, i.e., the water-solvent mixture, must be adjusted so that all components dissolve well. The ratios and weight specifications are guidelines for the skilled person. Among other things, the dissolving power depends on the temperature, so the subsequent processing temperature can also play a role in the choice of weight ratios. These relationships are known to the skilled person, and the foaming agent compositions can be optimized as usual.

[0043] The organic additives, as well as the acids and bases for pH adjustment (including inorganic ones) (pH regulators), are present in a proportion of 0 to no more than 20 wt.%. They are not required for some foaming agents. Therefore, their content is preferably as low as possible, i.e., preferably 0-10 wt.%, more preferably 0-5 wt.%, more preferably 0-3 wt.%, and particularly preferably 0-2 wt.%.

[0044] Highly foaming, alkali-stable, or even alkaline surfactants are generally suitable as surfactants. High foaming power is essential. Anionic surfactants are preferred, especially sulfonates, alkylsulfonates, especially alkali metal alkylsulfonates, alkylene sulfates, or alkyl ether sulfonates. The alkyl or alkylene chains of the sulfonates and sulfates are preferably long-chain and more preferably unbranched. Chain lengths greater than or equal to C8 and preferably between C10 and C20 can be considered typical.

[0045] Preferred surfactants include, among others, linear alkylate sulfonates, alpha-olefin sulfonates, beta-olefin sulfonates, alkyl ether sulfates, and ethoxylated alkylphenols. Currently preferred are alpha-olefin sulfonates, e.g., sodium C14-16 olefin sulfonate, and among the alkyl sulfates, SDS and SLS.

[0046] Other usable anionic surfactants are acyl amino acids and their salts, including acyl glutamates, such as sodium acyl glutamate, di-TEA palmitoyl aspartate, sodium caprylic / capric glutamate, or sodium cocoyl glutamate; acyl peptides, including hydrolyzed proteins and protein fractions; sarcosinates, taurates, acyl lactylates, alininates, arginates, valinates, prolinates, glycinates, aspartates, propionates, lactylates, and amide carboxylates. Phosphates / phosphonates are also suitable. Further examples are sulfosuccinates, sodium cocomonoglyceride sulfate, sodium lauryl sulfoacetate, or magnesium PEG-n-cocoamide sulfate; alkylarylsulfonates and acyl isethionates; ether and ester carboxylic acids, preferably of fatty acids; and other known foaming anionic surfactants that are commercially available.

[0047] It is intended that the ionic foam-forming surfactant contains or consists of at least one anionic surfactant. A single surfactant or a mixture of several surfactants can be used. As long as the foaming power is maintained, a mixture can contain at least one other, particularly nonionic, surfactant in addition to at least one anionic surfactant, although this is not preferred.

[0048] The solvent from the group of glycols (vicinal 1,2-diols, i.e. alcohols with OH groups on adjacent carbon atoms) is preferably selected from the group consisting of vicinal diols with 1 to 6 C atoms, diethylene glycol, triethylene glycol, and diethylene glycol ethers, although mixtures can also be used in each case. Since they are solvents, the glycols used are naturally liquid at room temperature. Preferred compounds are ethylene glycol, propylene glycol, hexylene glycol, butylene glycol, butyl diglycol, diethylene glycol, dipropylene glycol, diethylene glycol alkyl ethers with C1-C5 alkyl, dipropylene glycol alkyl ethers with C1-C5 alkyl, or mixtures thereof. The solvent brings all components of the foaming agent into solution together and forms a mixed phase with the water present in the foaming agent. Surfactant, ELF-HG and possibly other ingredients are present in an aqueous-glycolic solution.The solvent is present in the foaming agent at 0.1 to 60 wt.%, preferably at about 10 - 55 wt.%, more preferably at about 15 - 50 wt.%.

[0049] Furthermore, the agent contains a supporting fatty alcohol, as already known from the prior art according to DE 20 56 255 A1 and DE 38 07 250 A1. The dodecanol mentioned therein can also be used in this invention. In general, long-chain fatty alcohols with a chain length of C12 - C22 and preferably C14 to C20 are well suited. Fatty alcohols with a chain length of C16 to C18 are particularly well suited. By definition, fatty alcohols contain linear or slightly branched saturated or mono- or polyunsaturated hydrocarbon chains. Commercially available fatty alcohols are often of natural origin and frequently consist of mixtures for which the average chain length is stated. In the case of mixtures, the chain lengths stated above are to be regarded as average lengths.The fatty alcohol, together with the compound ELF-HG, ensures that the foam produced from the surfactant is particularly well stabilized, so that the foaming agent is also suitable for enabling longer standing times.

[0050] The foaming agent always contains a certain amount of water, even in concentrate form. However, the degree of dilution is flexible. For example, it may be desirable to have the agent as concentrated as possible to reduce transport and packaging costs for delivery to the site of use. On the other hand, for certain purposes, it may be advantageous to have the water required for mixing the binder already present in a preparation with the surfactant-containing foaming agent according to this invention, e.g., to save the user the trouble of measuring and mixing and to enable immediate use at the site of use. The water content of the agent can also be used to adjust the pH value. A wide variety of dilution degrees are possible for the surfactant-containing agent. The water content should amount to at least 10% by weight of the foaming agent.

[0051] For certain preferred embodiments, the volume of the base foaming agent or concentrate is further diluted with water up to 30 times its volume before being foamed.

[0052] The pH of the foaming agent, which is either used as such in the form of the specified mixture and optionally foamed beforehand for this purpose, or whose individual components are mixed into the overall mixture at a suitable point in the associated manufacturing process, is preferably greater than or equal to pH 6, particularly preferably the pH is alkaline, i.e. greater than 7. For many applications, the pH can be advantageously adjusted to values ​​from 6 to 13, preferably from 7 to 10. For this purpose, lye (preferably alkali lye, NaOH or KOH) can be added to the agent if necessary.

[0053] The foaming agent may also contain other additives, including pH regulators and supplementary solvents, but these should only be added in minor quantities.

[0054] Additives can be: retarders, accelerators, dyes, superplasticizers, water glass, silica, alkali salts and other well-known additives in the concrete, lime and gypsum industries.

[0055] Additional solvents can be, for example, C1-C20 monools or esters.

[0056] For example, butyl acetate or acetyl acetate, methanol or ethanol may be present as an additional solvent in smaller amounts.

[0057] However, it is preferred that the foaming agent consists essentially of the claimed and above-mentioned components.

[0058] As far as can be seen, there is no particular mixing sequence required for the production of the foaming agent.

[0059] A particular aspect of the invention is that the foaming agent—particularly its concentrate or a slightly diluted embodiment—can be freeze-dried or evaporated under vacuum and thus converted into a dry state. The freeze-dried or otherwise evaporated foaming agent can be stored and transported particularly well. It can also be mixed directly with the binder, thus producing a self-foaming binder mix in which the air pores develop in the mixer without the further addition of foaming agents. The dried foaming agent can also be dissolved in water at any time and reused like the liquid foaming agent described in detail above. Drying produces a powder that can be kept, stored, and transported in containers suitable for powders.

[0060] The invention further comprises various processes for producing air-entrained filling, lightweight construction and insulation materials which can be obtained with the aid of the foaming agent optimally stabilized with ELF-HG according to the invention.

[0061] In the first process, a binder paste consisting of the components binder, mixing water, and foaming agent is created with the optional addition of additives or aggregates. A foam of foamed pore-forming agent is mixed into the binder paste, which is then further processed into an air-entrained building material. Aggregates do not always need to be added to the binder paste. In this case, the binder paste is a building material paste that, after foaming, hardens and dries.

[0062] In a second process, the unfoamed liquid foaming agent is generally added to the mixing water, the binder mix, or by other means to the mixer where the materials are mixed to form the building material slurry. Here, the foaming agent can also be added in a powder, paste, or solid form obtained by freeze-drying. The foaming agent foams during the mixing process, in which the mixing water, solids, and additives are combined to form the slurry, thus creating a foamed building material slurry. The foaming agent is not foamed beforehand.

[0063] In the first process, the foaming agent is either diluted with water in a first step or foamed into a foam with the water already contained in the foaming agent. This occurs, for example, in a foam generator. Devices for this are known to those skilled in the art. The resulting foam can then be added to the binder paste or the building material slurry to produce a (porous) lightweight building material after drying, as described in more detail below.

[0064] In In preferred embodiments, the foaming agent, optionally pre-diluted with water, is foamed and the foam thus obtained is either 1. with the mixing water for glue / mash, 2. with the binder glue made from binder and mixing water and optional additives or 3. with the building material mash made from the binder glue and aggregates

[0065] to produce the foamed building material mash. The foam can be added indirectly to at least one of the starting materials or directly to the mash. The foam is either added directly to the mixer in which the mash is produced, or the foam is added / injected into the construction material mash's conveying hose.

[0066] According to a further aspect of the present invention, a method for producing a liquid air-porous building material, in particular a filling, lightweight construction or insulating material, from a foamed binder paste or from a foamed building material mash consisting of binder paste and aggregates and additives, wherein the binder paste consists of mixing water and binder, is particularly advantageous, which comprises the following steps: Preparation of the binder paste by mixing the binder and mixing water and, if necessary, preparation of the building material mash by mixing the binder paste with aggregates and additives, in which the foaming agent according to the invention, optionally with additional water, is added unfoamed to the dry binder, the mixing water, the binder glue or the building material slurry and the binder glue or the building material slurry is foamed in the mixer by the mixing process to produce the foamed binder glue or the foamed building material slurry.

[0067] This is possible without restriction for all known binder mixtures, although the effectiveness of the foaming agent and the required mixing time vary greatly. A liquid or freeze-dried foaming agent is added to the solid mix, the mixing water, or directly to the mixer in which the material mix is ​​mixed as usual. In this case, foaming occurs through intensive mixing of the binder mix and the mixing water in the selected mixer.

[0068] All process variants, as explained in more detail below in connection with the figures using gypsum as an example, are generally suitable for use with different binders, whereby variants of air-entrained filling, lightweight construction and insulation materials, associated products or liquid screeds and similar liquid-applied building materials are produced.

[0069] As already described above, the binder for the process according to the invention preferably consists of cement, gypsum, lime, each alone or in any desired mixture with each other or with other mineral components.

[0070] The method according to the invention includes the possibility of transporting the foamed construction material slurry directly to the site of construction, preferably by pumping, and allowing it to harden on site. If the binding agent in the foamed construction material slurry is Portland cement or high-alumina cement, this material can be used in road construction, replacing gravel and crushed stone layers, frost protection layers, hydraulically bound (base) courses, and parts of the asphalt structure.

[0071] The foamed building material slurry can also be incorporated into cavities, thus forming a composite material system with other building materials. This is particularly advantageous for floor or facade insulation, especially when these are to be installed retrospectively, i.e., in the field of building renovation. The porous lightweight construction and insulation material according to the invention is particularly well suited for insulation and leveling materials in floors, roofs, and walls, for screeds and underlying floor leveling compounds, and for ceiling and wall plasters.

[0072] The foamed building material slurry obtained according to the various process variants of the invention is stable under processing conditions, ie it can be transported in mobile mixers, pressed through hoses and piping systems with suitable pumps, transferred into molds for molded products or introduced as insulation material into gaps or onto floors without its density increasing or decreasing during the process.

[0073] However, the process also includes the possibility of pouring the building foam into a mold and thus producing molded bodies, in particular building elements.

[0074] In the production of plasterboard, the foaming agent can significantly reduce the weight of the final product by increasing the formation of stable air voids. This can also be achieved in combination with other additives.

[0075] In a particularly preferred embodiment, molding and curing takes place under pressure and elevated temperature in an autoclave, or in a mold that provides autoclave conditions. This process is particularly advantageous for the production of mechanically very stable aerated lightweight gypsum moldings and products made of autoclaved aerated concrete (YTONG).

[0076] Such a process for producing an air-entrained construction product, in particular a filling, construction or insulation element, comprises the steps Mixing binder, mixing water, optionally aggregates and additives as well as a foaming agent according to the invention, filling the resulting mixture into a mold and obtaining the porous building product by curing the mixture in the mold in an autoclave under at least one of the following conditions: increased pressure, increased relative humidity and increased temperature.

[0077] In a further preferred embodiment, it is possible to produce blocks using one of the above molding processes, from which further products are created through subsequent processing. In particular, it is provided that molded or free-cast blocks of lightweight construction and insulation materials obtained using the method according to the invention are cut, sawn, or milled into products such as lightweight panels, interior and exterior insulation elements, in particular facade insulation and panels, or molded blocks and molded elements.

[0078] If this process is carried out with material of higher density so that the required strengths are achieved, the process can be used to produce masonry blocks or fire protection panels of various classes. binder

[0079] Processes and foaming agents are applicable to all types of gypsum, ie dihydrate, hemihydrate and anhydrite in the various modifications, of natural or synthetic origin, including all FGD gypsums, especially alpha and beta hemihydrates.

[0080] The processes and foaming agents are still applicable to all types and grades of cement, ie Portland cement and high-alumina cement in the various modifications, of natural or synthetic origin.

[0081] All binders can contain the usual additives for the intended use, such as (ground) gravel, sand, silica products, setting retarders and accelerators, or the like. However, the binder content, based on the dry mass, is preferably at least 12.5 wt.%. For applications where the binder content in the dry mass is 100 wt.%, the process is also very suitable for pure gypsum or pure cement.

[0082] The means and methods according to the invention result in stable binder foams, even with low bulk densities (< 500 kg / m³). Foamed construction products made from them have high thermal insulation values.

[0083] The density of the foamed building material slurry, and thus of the final product, can be adjusted within wide limits. This allows the foamed building material according to the invention to be produced in virtually any desired density. Air-entrained building materials with weights between approximately 90 kg / m³ and 1,700 kg / m³ have been produced and tested.

[0084] The foamed building material slurries obtained with the agent according to the invention can be processed at temperatures above 0° Celsius and have excellent thermal insulation properties and, despite their low density, very good sound insulation properties. Detailed description of the invention

[0085] The invention is illustrated below using recipe and process examples. These serve to better illustrate the invention and do not limit its general aspects. Recipe examples - foaming agents: Example foaming agent 1

[0086] 6.0 wt.% anionic surfactant, alkanesulfonate 1.5 wt.% fatty alcohol, C12-C14 Mix 70:30 18.0 wt.% butyldiglycol (diethylene glycol monobutyl ether) 5.0 wt.% ethoxylated fatty alcohol C16-C18 (degree of ethoxylation: EO 25) 69.5 wt.% water 100% total solution, application dilution 1:6 Example foaming agent 1 a (concentrate)

[0087] 16.0 wt.% anionic surfactant, alkanesulfonate 5.0 wt.% fatty alcohol, C12-C14 Mix 70:30 46.0 wt.% butyldiglycol (diethylene glycol monobutyl ether) 5.0 wt.% ethoxylated fatty alcohol C16-C18 (degree of ethoxylation: 50) 28.0 wt.% water 100% total solution, dilution 1:12 Example foaming agent 2

[0088] 10.0 wt.% anionic surfactant, sodium C14-16 olefin sulfonate 10.0 wt.% sulfuric acid ester salt 3.0 wt.% fatty alcohol, C10-C12 mix 50:50 15.0 wt.% hexylene glycol 3.0 wt.% ethoxylated PEG (polyethylene glycol) (degree of ethoxylation: EO 23) 59.0 wt.% water 100% total solution, use dilution 1:4 Example foaming agent 3

[0089] 6.5 wt% anionic surfactant, sodium C14-16 olefin sulfonate 1.5 wt% fatty alcohol, C12-C14 Mix 30:70 15.0 wt% butyldiglycol 5.0 wt% ethoxylated natural resin (LUCRAMUL U-Flakes) (Ethoxylation degree: EO 50) 72.0 wt.% water 100% total solution, dilution 1:4

[0090] Foams from these foaming agents are mixed with binder glue or building material slurry to form foamed building material slurry.

[0091] If the ethoxylated compound ELF-HG is omitted from the formulation of a foaming agent, the pore former loses its stability.

[0092] A building material glue is produced in the usual way. For example, the compositions listed in Example Mixture 1, 2, or 2a can be selected. The exact solids composition and water content depend on the intended use of the foamed mash. The type and quantity of the selected aggregates and the composition of the binder mix are selected accordingly. Different amounts of foam are used depending on the desired density of the final product. Example mixture 1 plaster glue:

[0093] 1. the desired amount of alpha hemihydrate 2. of which 45 wt.% mixing water 3. 2.1% retarder (tartaric acid) Example mixture 2 cement paste with superplasticizer:

[0094] 1. the desired amount of Portland cement 2. of which 40 wt.% mixing water 3. 2.0 wt.% of the binder weight superplasticizer naphthalenesulfonate or MELFLUX (BASF) Example mixture 2 a cement paste without superplasticizer:

[0095] 1. the desired amount of Portland cement 2. of which 60 wt.% mixing water Examples of applications:

[0096] APPLICATION 1: Production of a plasterboard for interior insulation.

[0097] Desired wet density = 450 kg / m 3< , binder used: gypsum, alpha hemihydrate including retarder, aggregates: none.

[0098] To produce one cubic meter of foamed gypsum slurry, which reaches the desired density after curing in the ambient air in the drying container, 450 kg of gypsum paste is required. According to Example 1, 450 kg of gypsum paste contains 310 kg of gypsum and 140 liters of water. Gypsum has a density of 1.7. 310 kg of gypsum therefore has a volume of 182.4 liters. Together with the water, this results in a volume of 322.4 liters. The remaining volume of 677.6 liters per cubic meter is filled with foam from Example Foaming Agent 1 and mixed with the paste to produce one cubic meter of foamed gypsum slurry.

[0099] APPLICATION 1a:Production of a lightweight concrete slab for exterior insulation. Desired wet density = 600 kg / m³, binder used according to example mix 2.

[0100] To produce one cubic meter of foamed mash, which reaches the desired density after curing in the ambient air in the drying tank, 600 kg of cement paste are required. According to Example Mix 1, this consists of 430 kg of cement and 170 liters of water. Cement has a density of 3.1. 430 kg of cement therefore has a volume of 139 liters. Together with the water, this results in a volume of 309 liters. The remaining volume of 691 liters per cubic meter is filled with foam from Example Foaming Agent 3 and mixed with the paste to produce one cubic meter of foamed mash.

[0101] APPLICATION 2:Production of a leveling compound for liquid application on site beneath the screed. Desired density = 400 kg / m³, desired strength = 1.5 N / mm², binder used: gypsum, natural anhydrite, aggregates: 25% by weight ground fine-grain gravel, activator: potassium sulfate 2.0% by weight of the binder.

[0102] To produce a foamed gypsum slurry that hardens in the air at the installation site, 207 kg of anhydrite with a density of 2.2 and a volume of 94 liters are required. The aggregates have a density of 2.7 and thus a volume of 37 liters, so 869 liters of foam are required for one cubic meter of leveling compound. Two liters of foaming agent according to Example 2 are added to the mixing water, and the entire mixture is mixed in an intensive mixer to form a foamed slurry.

[0103] APPLICATION 3:Production of a base layer in road construction, in the use of which all layers and elements below the covering asphalt layer can be dispensed with.

[0104] Desired density: 850 kg / m³, desired compressive strength: 3.5 N / mm², binder used: Portland cement, CEM I 42.5 N.

[0105] To produce a foamed concrete slurry that hardens at the point of installation, 531 kg of cement with a density of 3.1 and a volume of 171 liters are required according to Example Mix 2a. Together with the volume of mixing water of 510 liters, this results in a volume of 681 liters, which is mixed with 319 liters of foam prepared from Example Foaming Agent 1 to produce the desired material.

[0106] APPLICATION 4:Production of a lightweight gypsum plaster for the interior of an exterior wall. Desired density = 750 kg / m³. Binder used: gypsum, alpha hemihydrate, 25 kg bagged (standard hardware store product). Aggregates: factory-installed retarder, none other additives.

[0107] To produce lightweight gypsum from foamed gypsum mash, which reaches the desired density after curing in ambient air, 25 kg of gypsum (bagged) are mixed with 10 liters of water to form gypsum paste. Gypsum has a density of 1.7, which results in a volume of 15 liters for 25 kg of gypsum. Together with the water, this results in a volume of 25 liters.

[0108] Alternative 1: The glue is mixed with 25 liters of foam according to Example Foaming Agent 1 to form a foamed mash.

[0109] Alternative 2: The foaming agent concentrate is added to the solid or mixing water in dried or paste form, and the mixture is foamed in an intensive mixer. For this purpose, 1.0 g of powder (prepared from Example Pore Former 1) is added to 25 kg of gypsum. FIGURE DESCRIPTION

[0110] The drawing shows: Fig. 1 shows the schematic process for manufacturing a lightweight building material on the construction site or in industrial production; Fig. 2 shows the schematic process for manufacturing a lightweight building material using a slightly modified process; Fig. 3 shows the schematic process for manufacturing a lightweight building material using a dried foaming agent.

[0111] Figure 1shows a first process sequence for producing a foamed building material slurry, from which (porous) lightweight building material products are produced or manufactured after drying. The required raw materials are fed from storage containers 1, 2, and 3 to a standard mixer 4. Various mixer types can be used. However, the mixing intensity should be variably adjustable so that the desired density (the desired pore volume) is achieved when the foaming agent is added to the mixer without foaming.

[0112] The binder is placed in dry form in tank 1. It may contain aggregates. This solid mix is ​​conveyed to mixer 4 via line a. Alternatively, the binder and aggregates can be stored in separate storage and discharge tanks, which would be connected to the mixer via separate lines (not shown here). In parallel, the mixing water from tank 2 is conveyed to mixer 4 via line b.

[0113] Foam is fed into foam generator 3 and pumped into mixer 4 via line c. Mixer 4 produces a foamed building material slurry, which is pumped via line d and pumped by a pump 5 to the installation point on a construction site or into a mold for curing. Alternatively, the foam can be fed directly into the building material slurry via line e. For this purpose, the foam from line e is injected into the glue stream of the unfoamed binder glue or the unfoamed building material slurry.

[0114] The transfer lines d, d', and g can be flexible hoses through which the foamed slurry is introduced to a shoring point. The slurry can be used as insulation material in partition walls, as plaster, as floor leveling compound, or as screed.

[0115] Figure 2shows a modified process. In this process, a binder paste or a building material mash, previously produced, e.g., in a ready-mixed concrete plant, is added to container 1 directly from the transport mixer, or the mash is fed via line d' to pump 5. Alternatively, the foam can be fed to the transport mixer via line c', whereby the transport mixer fulfils the function of mixer 4 and replaces it. The two components, binder paste and foam, are mixed in mixer 4 or in the transport mixer, and a foamed building material mash is formed, as in the process to Figure 1 From mixer 4 (via path d) or from the transport mixer (via path d'), the foamed building material slurry is pumped to the installation point 6 or into a mold by means of pump 5. Aggregates may have previously been added directly from a separate container into mixer 4 or the transport mixer.

[0116] Figure 3shows an example of a process in which a powdered, dry foaming agent is used. Again, a solid mix, i.e. binder and any additives, is placed in container 1. Container 2 contains mixing water. Container 7 now contains the dry, for example freeze-dried, foaming agent, which is added via line c to the binder in container 1 and / or the mixing water in container 2. The powdered foaming agent is fed to the mixer 4 via the material flow or it is added directly to the mixer 4 (here schematically paths a, b, f). In the mixer 4, a binder glue foam or a foamed building material slurry is produced, which, as already described for the previous figures, is transported via line d by means of pump 5 to the installation point 6 or into a mold. Quality tests

[0117] Foamed building material slurries must meet predefined requirements. These requirements are derived from the desired building product. The selected composition of the building material slurry is often a trade secret, and the number of possible combinations and the varying concentrations of individual components do not allow for a generally valid quality test for foamed building material slurries. However, a series of general tests has been established that demonstrate the quality of the improved stability of the foaming agent in the building material slurry claimed by this invention. Of course, a stable foam is no guarantee of a good building product. The selected binder mixture, the added additives, and the manufacturing and drying processes used play too large a role in achieving a defined quality. However, without a functioning foaming agent, no air-entrained building product is possible.Particularly for applications on construction sites, where critical parameters constantly fluctuate, robust and reliable stability of the foam used is essential. In an industrial manufacturing process, parameter deviations are smaller. Materials, temperatures, and procedures are standardized internally. However, even here, the pore-forming agent must withstand the process and offer a robustness that ensures satisfactory results despite parameter deviations.

[0118] The tests described below are general in nature and applicable in most cases. Often, only a combination of the described tests can help determine the suitability or non-suitability of a pore-forming agent.

[0119] For a series of quality tests, the desired building material mash is prepared. In the following example, we tested the following mixtures: A - A gypsum paste made from alpha hemihydrate, here Südanit from CASEA GmbH, and tap water. B - A cement paste made from Portland cement, here CEM I 42.5 R from Holcim Germany, and tap water.

[0120] Both mixtures are mixed with a foam which is foamed from foaming agent according to Example Mixture 3 in a 2-pump foam generator from Finke in Detmold.

[0121] In principle, the foam can be added at any time before the building material glue hardens, but it should be added as soon as possible after the glue has been prepared. The glue must remain uncured to allow mixing with the foam.

[0122] In principle, the foamed building material mash can be produced in different compositions and different densities. Test 1: Pump stability

[0123] The glue or mash can be pumped with any pump type currently available on the market; peristaltic and screw pumps are suitable for foamed mashes. The variety of available pumping principles and the variable foam addition points require a practical test to determine whether the selected pump can achieve the desired result.

[0124] It is irrelevant whether the pumps transport material produced in a batch process or whether the material is produced continuously.

[0125] It is irrelevant whether the lightweight gypsum is produced in advance, in the pump, directly downstream of the pump in the delivery hose / pipe, or in the low-maintenance or maintenance-free agitator / mixer element. However, it should be noted that piston pumps can destroy the pores of foamed mashes. Test procedure:

[0126] The density of the foamed mash is measured before and after pumping. The pumping test is passed if the density measured after pumping corresponds to the density measured before pumping, or to the previously defined target density. Test 2: Stability when moving and pouring

[0127] Foamed mashes based on any solid mixture must be pumped from the mixing point to the drying point. The pumping process is described in Test 1. In addition, the material may need to be poured off, meaning it must be moved again at the installation point. This movement is simulated in the test. Test procedure:

[0128] The foamed mash is filled into a container and poured from a predefined height into a second container. If necessary, the material is stirred or otherwise mechanically agitated to simulate the actual production process. The density is measured before and after pouring. If a foaming agent according to the invention is used, the density remains unchanged. When pouring foamed building material mashes according to the invention, drop heights of over 3 m are possible. Test 3: Standing stability

[0129] Depending on the selected composition, the foamed building material slurry can withstand build-up heights of over 150 cm in a single application. The material remains volume-stable with uniformly distributed air pores. Test procedure:

[0130] Foamed mash is poured into a container where the material can dry. After the filling process, the upper filling limit is marked. After drying, the upper edge of the building material must still be at the marked point. If the material has slumped during drying, it has lost volume. Pores have dissolved, the contained air has escaped, the material collapses, and the density cannot be maintained. The foam is unstable. Remarks on the stabilities determined in tests 1-3:

[0131] Any gypsum- or cement-based mash can be foamed, provided the mix contains no additives that neutralize the pore-forming agent or otherwise deprive it of its properties (defoamers). However, volume stability can generally only be achieved if a sufficient amount of suitable binder is present in the building material mash. Even the best pore-forming agent cannot permanently stabilize a mix that cannot develop sufficient stability from the binder mix used during the drying process.

[0132] Experience shows that the binder content in the mash should be at least 12.5% ​​of the total solid mass. Test 4: Homogeneity of air void distribution

[0133] In the dried building material, it may be necessary to determine whether the air pores retain their size and distribution throughout the room during the drying process, or whether inhomogeneities have developed. To do this, a pre-defined number of identically sized test specimens are cut from a sufficiently sized specimen made up of different layers. The average size of the air pores on these specimens is determined under a microscope or using a CRT. The specimens are then weighed. Identical densities indicate a homogeneous distribution of the pores in the system. Inhomogeneities form when pores detach from the structure of the foamed building material slurry, forming lenses with a higher proportion of pore-forming agent and lenses with a higher proportion of slurry. The slurry usually settles at the bottom and the pores migrate to the top.Depending on the application, this development can be a criterion for exclusion, rendering the foamed building material slurry unsuitable for the intended purpose. Test 4 offers a simple means of detecting inhomogeneities even without CRT. General information on comparison tests:

[0134] The tests can be conducted individually or in their entirety as suggested, and of course, they can be further supplemented. If a test procedure is defined and alternative foams are used for comparison, it can be seen that foams made from foaming agents produced according to the invention are superior to alternative foams, with predefined target values ​​being better achieved in individual or all tests. Comparison of foaming agents:

[0135] To compare a foaming agent according to the invention with an alternative, a foaming agent S according to Example Recipe 3 is compared with a foaming agent S-, where S- also corresponds to Example Recipe 3, but no ELF-HG is added to S-. The mash used in this comparison corresponds to that described in Reference Mixture I. The mixture according to Table 1A is brought to the desired density (Table 1B) by mixing in pre-foamed pore former. The foamed building material mash thus obtained is subjected to tests 1 to 3. A standard Eirich mixer was chosen as the mixer. The foam was produced using a Finke foam generator. The foam was mixed into the standard mixer after the mash had been produced. A peristaltic pump was chosen as the pump. The filling container is a wooden container made in-house.

[0136] Table A shows the test results. Table A Designation Manufacturing density (kg / m3) Manufacturing volume n (l) Density after pumping test (kg / m3) Installation height (cm) Start of stand test Installation height (cm) End of stand test S 800 500 800 80 80 S- 800 500 1.600 80 47

[0137] It turns out that foaming agent S passes both the pumping test and the slump test without any problems. Volume and thus density remain the same. The density does not decrease during pumping. In the slump test, the initial fill level is still maintained after the mash has set, meaning the material has not lost any volume.

[0138] Foaming agent S- exhibits significant weaknesses in comparison. A large portion of the volume is lost during the pump test. During the slump test, the build height is reduced by over 40%, from 80 cm to 47 cm. This indicates a failure of the pore-forming agent S-. For the slump tests, material was produced again with pore-forming agent S-, as the material from the pump test had already failed. Since it is possible for a material to fail the pump test but pass the slump test, the slump test was conducted with a second mixture.

[0139] In this comparison of S and S-, the pore former is optimally stabilized according to the invention by the use of ELF-HG. Reference mixtures I: Lightweight concrete production by adding a foam to the pre-prepared cement paste

[0140] The following applies to the mixtures shown in Table 1 below. All mixtures using cement as an example: 1- Mixture A (reference mix), unfoamed 2- Mixture B, lightweight concrete, density 0.8 kg / liter or 800 kg / m 3< 3- Mixture C, lightweight concrete, density 0.4 kg / liter or 400 kg / m 3< Table 1 Designation Density (kg / m3) Total volume (I) of which foam (l) of which cement (l) of which water (l) A 1.800 1.000 0 400 600 B 800 1.000 560 180 260 c 400 1.000 775 90 135

[0141] To produce one cubic meter of foamed lightweight concrete, the following quantities are required: Cement, here CEM 1 42.5, required, column "of which cement": A: 1,200 kg cement B: 540 kg cement C: 270 kg cement

[0142] Water, here tap water, column "of which water": A: 600 kg water B: 260 kg water C: 135 kg water

[0143] Foam, here made from reference mixture 1, column "of which foam": A- 0 litres of foam B- 560 litres of foam C- 775 litres of foam

[0144] From 60% to 110% of the specified water quantities can be used without damaging the lightweight concrete structure. Lower or higher water contents are possible, but are not recommended due to potentially adverse effects such as increased toughness, excessively rapid or incomplete setting, etc.

[0145] The reference mixtures can be carried out with all conceivable solid mixtures and foam densities. When calculating foam volumes and the resulting amounts of pore-forming agents, the varying densities of the solid mix must be taken into account. II. Lightweight gypsum production by adding the unfoamed foaming agent to the mixing water during gypsum paste production

[0146] To produce 5.0 liters of gypsum glue, an alpha hemihydrate from CASEA GmbH and tap water are used. The gypsum glue is mixed in a 7-liter mixer. An undiluted pore-forming agent according to Example 1 is added to the mixed water. The pores are created during the glue-mixing process.

[0147] The following applies to the mixtures shown in Table 2 below. All mixtures, using gypsum as an example: 1- Mixture X (reference mix), unfoamed 2- Mixture Y, lightweight gypsum, density 0.7 kg / liter or 700 kg / m 3< 3- Mixture Z, lightweight gypsum, density 0.5 kg / liter or 500 kg / m 3< Table 2 Designation Density (kg / m3) Total volume (l) of which foam (l) of which gypsum (l) of which water (l) X 1.600 5,0 0 5,5 2,75 Y 700 5,0 2,9 2,3 1,15 Z 500 5,0 3,5 1,8 0,63

[0148] The following quantities are required: Gypsum, here alpha hemihydrate from CASEA GmbH, column "of which gypsum": X: 1,200 kg gypsum Y: 540 kg gypsum Z: 270 kg gypsum Water, here tap water, column "of which water": X: 2.75 kg water Y: 1.15 kg water Z: 0.63 kg water Foam, here produced from reference mixture 1, column "of which foam": X - 0 liters foam Y - 2.9 liters foam Z - 3.5 liters foam

[0149] The following undiluted foaming agent as per Example Foaming Agent 3 is required: a. 0.00 liters b. 0.02 liters c. 0.03 liters

Claims

1. Foaming agent for foaming a binder glue or a binding material slurry for the production of air pore containing construction materials, in particular filling, lightweight and insulating materials, which agent consists of the following: a) 0.1 to 65.0 wt.%, preferably 4.0 to 25.0 wt.%, particularly preferably 12.0 to 17.0 wt%, ionic, preferably anionic, foam-forming surfactant; b) 0.05 to 9.0 wt.%, preferably 1.0 to 7.0 wt.%, particularly preferably 2.0 to 6.0 wt.%, of at least one compound which is solid at room temperature, selected from the group consisting of ethoxylated fatty alcohols having an alcohol chain in the carbon base structure with at least 12 carbon atoms, ethoxylated natural resins, ethoxylated artificial resins and ethoxylated glycols; c) 0.1 to 7.0 wt.%, particularly preferably 2.0 to 6.0 wt.% fatty alcohol having a chain length of C10 to C18, preferably of C12 to C16; d) 0.1 to 60.0 wt.%, preferably from 10.0 to 55.0 wt.%, particularly preferably from 15 to 50.0 wt.% of solvent selected from the group of vicinal diols having from 1 to 6 carbon atoms, diethylene glycol, triethylene glycol and diethylene glycol ethers; e) 0 to 20 wt.% of organic additives; f) 0 to 20 wt.% of pH regulators; g) 0 to 99.75 wt.%, preferably 20.0 to 85.0 wt.%, particularly preferably 15.0 to 75.0 wt.%, of water, wherein the mixture yields a total of 100 wt.%.

2. Foaming agent according to claim 1, characterized in that components a) to d) are present in the following ratios: - a) surfactant to b) solid ethoxylated compound: 1:1 to 12:1, preferably 3:1; - d) solvent to b) solid ethoxylated compound: 2:1 to 16:1, preferably 9:1; - c) fatty alcohol to b) solid ethoxylated compound: 1:4 to 5:1, preferably 1:1; - a) surfactant to c) fatty alcohol: 1:1 to 12:1, preferably 3:1; - a) surfactant to d) solvent: 5:1 to 1:12, preferably 1:3; - c) fatty alcohol to d) solvent: 2:1 to 1:16, preferably 1:9.

3. Foaming agent according to claim 1 or 2, characterized in that it is diluted to up to 30 times of its volume with water before foaming.

4. Foaming agent according to one of claims 1 to 3, characterized in that it is in pasty or powdery solid state obtainable by freeze-drying or evaporation in vacuo.

5. Use of the foaming agent according to one of the claims 1 to 4 for stabilizing a foam used in the production of air pore containing construction materials, in particular filling, lightweight and insulating materials.

6. Method for producing a liquid air pore containing building material, in particular a filling, lightweight construction or insulating material, from a foamed binder glue or from a foamed binding material slurry consisting of binder glue and aggregates and additives, wherein the binder glue consists of mixing water and binder, comprising the following steps: - preparing the binder glue by mixing binding agent and mixing water - and where applicable preparing the binding material slurry by mixing the binder glue with aggregates and additives, characterized in that the foaming agent according to one of claims 1 to 4, optionally with additional water, is added unfoamed to the dry binding agent, the mixing water, the binder glue or the binding material slurry, and that the binder glue or the binding material slurry is foamed in the mixer by the mixing process to yield the foamed binder glue or the foamed binding material slurry.

7. Method according to claim 6, further comprising the step of curing the binding material slurry to obtain the solid air pore containing building product.

8. Method according to claim 6, characterized in that the foamed binding material slurry is filled into a mold and cured, wherein the curing takes place in a mold in an autoclave under at least one of the following conditions: increased pressure, increased relative humidity and elevated temperature.

9. Method according to claim 7 or 8, further comprising the step of shaping the solid air pore containing building product, particularly by cutting, sawing or milling.

10. Liquid air pore containing building material, particularly filling, building or insulating material, obtainable by the method of claim 6.