WO2006027035A1

WO2006027035A1 - System and method for producing a foamed material containing plaster

Info

Publication number: WO2006027035A1
Application number: PCT/EP2005/006456
Authority: WO
Inventors: Matthias Passmann; Gaby Schilling; Milan Sebestian; Wilfried Hübner; Felicitas Kolenda
Original assignee: Henkel Kommanditgesellschaft Auf Aktien
Priority date: 2004-09-11
Filing date: 2005-06-16
Publication date: 2006-03-16
Also published as: EP1794101A1; DE102004043968A1

Abstract

The invention relates to a system for producing a foamed material containing plaster, in particular in the form of a water-based dispersion. Said system comprises (i) hardenable plaster, (ii) at least one organic polymer which can foam together with the hardenable plaster, (iii) at least one foaming agent, (iv) optionally, at least one hardening retarder and (v) optionally, at least one hardening accelerator. Materials containing said plaster can foam easily due to said inventive method. It is also possible to produce foamed plaster materials ('plaster foam') which hardens and drys relatively quickly. The hardening and/or drying time is generally less than 24 hours. The generally water-based plaster foam applied according to the invention and which drys relatively quickly, in particular, in less than two hours, is dimensionally stable due to the hardened plaster and has a relatively high resistance.

Description

System and method for producing a foamed gypsum-containing material

The invention is in the field of plasters and gypsum-containing building materials. In particular, the present invention relates to a system for producing a foamed gypsum material and the gypsum material ("gypsum foam") obtainable with this system itself. Furthermore, the present invention relates to a method for producing a foamed gypsum material or a method for foaming a gypsum material as well as to this Way available gypsum material ("gypsum foam") itself.

When in the context of the present invention of "gypsum" is mentioned, so it is generally gypsum in an unbound, d. H. So meant in a still settable form. Such unbound or settable gypsum can be produced industrially by partial dewatering of calcium sulphate hydrates, in particular calcium sulphate dihydrate. The dehydration is usually up to about the level of hemihydrate hemihydrate. Such calcium sulphate hemihydrates occur in various modifications, for example in the modifications referred to as α- and β-modifications. In completely anhydrous form, the calcium sulfate is present in particular in the form of the anhydrite.

Abbindefähiger or not-bound gypsum in the context of the present invention therefore denotes in particular the Calciumsulfathemihydrate and anhydrous calcium sulfate, in particular anhydrite. As raw material for drainage to settable or non-gypsum gypsum can be used, for example, occurring in natural deposits or gypsum incurred in flue gas desulphurisation plants.

For use for building purposes or for the production of moldings, gypsum or gypsum-containing mortar mixtures are mixed with water. In the process, the lower hydrates of the gypsum formed during dewatering finally form the crystalline calcium sulfate dihydrate. As a result of the binding of the water and the Growth of usually acicular crystals of calcium sulfate dihydrate cures the gypsum or mortar.

To extend the setting times, so-called setting retarders ("retarders") can be added to the gypsum; These are additives or additives (additives) that delay setting - also known as curing. Such retarders are described, for example, in German patent application DE 101 27 060 A1, which is based on the applicant himself, or in EP-A-0 607 039, EP-AO 633 390, EP-A-1 270 530, US Pat. 5,488,991, US-A-5,484,478 and US-A-5,908,885, the entire contents thereof

The disclosure is hereby incorporated by reference. Due to their setting retarding effect, the retarders are sometimes synonymously referred to as hydration retardants or hydration inhibitors.

By contrast, the setting times of the gypsum can be shortened by means of so-called accelerators or the effect of the retarders prolonging the setting time can be canceled.

Foamed materials have the advantage of lower weight per volume over non-foamed materials, i. H. So a lower density. In this way, in the application - compared to non-foamed material - more volume can be filled with less raw materials, resulting in a considerable Gewichts¬ and thus cost savings.

Foamed building materials, in particular polyurethane foams (PU foams) or acrylic-based plastic foams, are used in particular for filling cavities and interstices.

Although polyurethane foams (PU foams) have the advantage that they react quickly and thus quickly reach high strengths, but have the disadvantage that they are subject to labeling and can not be wiped off in case of misuse. Existing dispersion-based foams from the aerosol can (z. B. GREAT STUFF ^® Acrylic Latex Foam Sealant by the company. DAP) are very soft and not very cohesive foams which, although wiped off shortly after a misapplication of water, but long due to the high water content drying times , generally more than 24 hours.

Numerous attempts have already been made in the prior art to foam gypsum-containing building materials (cf., for example, GB-PS 1 325 544 or EP-A-1 403 227). However, the known from the prior art gypsum foams have the disadvantage that they have relatively long drying times or have no sufficient stability after curing. Other known from the prior art systems based on gypsum foam have the disadvantage that after foaming still post-expansion or shrinkage of the applied gypsum foam occurs, so that the final volume can not be set or controlled exactly. In turn, other known systems based on a gypsum-containing foam have the disadvantage that they do not have sufficient stability after drying or hardening.

An object of the present invention is thus to provide a system and a method for producing a foamed gypsum-containing material ("gypsum foam"), which in particular avoids the disadvantages of the prior art described above.

In particular, it is an object of the present invention to provide a system or method for producing a foamed gypsum-containing material capable of producing foamed gypsum-containing materials having relatively short drying times, preferably less than 24 hours, and shortly after application Removable or wiped with water. In particular, it should be possible with such a system or such a method to produce foamed gypsum materials which show no or no significant post-expansion and no or no appreciable shrinkage. Furthermore Foamed materials should be producible in this way, which have sufficient strength and dimensional stability after drying or setting.

The present invention - according to a first aspect of the present invention - is thus a system for producing a foamed gypsum-containing material, in particular in the form of an aqueous-based dispersion, wherein the system

(i) settable gypsum,

(ii) at least one organic polymer which is foamable together with the settable gypsum,

(iii) at least one propellant,

(iv) optionally at least one set retardant and

(v) optionally at least one setting accelerator

includes.

As regards the settable or non-gypsum plaster used in accordance with the invention, in particular all settable or non-bonded calcium sulfates are suitable according to the invention. For example, the settable gypsum may be in the form of a settable hydrated calcium sulfate or in the form of a settable anhydrous calcium sulfate, especially in the form of anhydrite. In the context of the present invention, the settable gypsum is particularly preferably in the form of a calcium sulfate hemihydrate.

As far as the amount of settable gypsum in the system according to the invention is concerned, this can vary within wide ranges. In general, the gypsum in amounts of 5 to 70 wt .-%, in particular 10 to 60 wt .-%, preferably 25 to 40 % By weight, based on the system according to the invention. Similarly, it is also possible to deviate from the aforementioned amounts, if this should be required by the application.

By the amount of gypsum can be - in addition to the drying time - specifically set and control the hardness and strength achieved after drying or setting and the weight of the generated "gypsum foam ¹¹ .

As far as the organic polymer used according to the invention is concerned, it must, together with the gypsum, form a coherent, homogeneous, curable foam

Give or deliver mass. Together with the gypsum, the organic polymer acts as a binder and hardens after application of the foamed material together with the gypsum into a solid mass ("solidified foam"), which has sufficient strength or dimensional stability to be used as a building material or building material become. Therefore, in the context of the present invention, the organic polymer is also referred to as "polymeric organic binder".

Since the preferred application of the system according to the invention is an aqueous-based dispersion, it is advantageous if the organic polymer is a water-soluble or water-dispersible polymer. In particular, the organic polymer is used in dissolved or dispersed form, in particular in the form of an aqueous-based dispersion or solution. Therefore, so-called dispersion polymers are used in particular in the context of the present invention.

The amounts with which the organic polymer used according to the invention is used in the system according to the invention can vary within wide limits. In general, the organic polymer used according to the invention, based on the system according to the invention, in amounts of 5 to 85 wt .-%, in particular 20 to 75 wt .-%, preferably 30 to 70 wt .-%, used. When the organic polymer used according to the invention is in the form of a dispersion, in particular in the form of an aqueous dispersion, this aqueous dispersion containing the polymer is generally used in amounts of from 20 to 90% by weight, in particular from 30 to 75% by weight. . preferably 40 to 70 wt .-%, based on the inventive system used; Usually, polymer dispersions having a solids content (polymer content) of from 20 to 80% by weight, in particular from 30 to 70% by weight, preferably from 40 to 65% by weight, based on the dispersion, are used. Similarly, it is also possible to deviate from the aforementioned amounts, if this should be required by the application.

In conjunction with the amount of gypsum can be adjusted by the amount of polymer used - in addition to the drying time - specifically achieved after drying or setting hardness and strength and the weight of the generated "gypsum foam" or control.

In order to enable a good application or a good application of the foamed gypsum-containing material, it is preferred according to the invention if the organic polymer has film-forming properties.

Particularly good application or application properties are obtained if the organic polymer used according to the invention has number-average molecular masses M _n > 100,000, in particular M _n > 500,000, preferably M _n > 750,000, particularly preferably M _n > 1,000,000.

As far as the organic polymers used according to the invention are concerned, a multiplicity of polymers and copolymers are suitable here which have the abovementioned properties.

For example, the organic polymer used according to the invention may be selected from the group of polymers and / or copolymers based on

Acrylic and methacrylic acids and their esters, amides and nitriles;

Maleic acids and their anhydrides and esters; styrenes;

• vinyl acetates;

• vinyl chloride and vinylidene chloride;

Alkylene and alkadienylene, especially ethylene, propylene, butadiene and isoprene;

Vinyl esters of versatic acid, in particular VeoVa 9, 10 and 11;

• viny lethern;

Reactive monomers, in particular methylolacrylamide;

Silane-containing monomers, such as vinylalkoxysilanes;

and or

• vinyl pivalate.

Furthermore, the organic polymer may also be selected from the group of polyvinyl alcohols, polyvinyl pyrrolidones, polyethylene glycols and hydroxyethyl cellulose and mixtures thereof.

Likewise, the organic polymer used according to the invention may be a polyurethane-based polymer, in particular in the form of an aqueous-based polyurethane dispersion.

Examples of the present invention can be used polymer dispersions are for example aqueous dispersion of an acrylate polymer with a solids content of about 50% from Rohm & Haas with the label Primax ^® 310 and of the BASF AG distributed dispersion of a styrene / butyl acrylate polymer called Acronal ^® 290D having a solids content of about 50%,

As regards the blowing agent used according to the invention, this causes the actual foaming process, d. H. the production of the foamed gypsum-containing material based on the above-described settable gypsum together with the organic polymer described above.

The propellant should in particular be selected such that it acts at least substantially with respect to the organic polymer or at most only slightly swelling. In particular, the blowing agent should be selected such that from the organic polymer at most 0 to 25 wt .-%, in particular at most 1 to 20 wt .-%, preferably at most 5 to 15 wt .-%, based on the organic polymer, of the blowing agent are receivable. In this way, a Nachexpansion or shrinkage of the foamed gypsum-containing material is prevented.

Particularly suitable blowing agents according to the invention are liquid at room temperature under atmospheric pressure. Propellants preferred in accordance with the invention are emulsifiable in the aqueous phase. The aforementioned properties facilitate the application of the system according to the invention. Blowing agents which are liquid at room temperature under atmospheric pressure also have the advantage that, for example when they leave a closed container (eg a can), the volume expansion is greater than with gaseous propellants. A high volume expansion of the propellant in turn leads to a low density of the applied foam, d. H. descriptive spoken, can be produced with little starting material, a larger foam volume.

In addition, propellants which are liquid at room temperature under atmospheric pressure have the advantage that the gypsum and the polymer are dispersible therein, so that homogeneous dispersions can be produced after intensive mixing (for example by shaking). Propellants which are suitable according to the invention are selected, for example, from the group of alkanes, in particular propane, butane and isobutane, and also mixtures of propane and butane; Ethers, in particular dimethyl ether; fluorinated hydrocarbons, in particular 1, 1, 1, 2-tetrafluoroethane and 1, 1-difluoroethane; carbon dioxide; Nitrous oxide (nitrous oxide, N ₂ O); and mixtures of the aforementioned blowing agents. Since fluorinated hydrocarbons are relatively expensive and can also cause ozone depletion and carbon dioxide can lead to acidification of the system according to the invention and thus to coagulation of the dispersion are propellants based on alkanes, especially propane, butane and isobutane and mixtures of propane and Butane, and ethers, in particular

Dimethyl ether, preferred. Since isobutane has a lower pressure than propane and butane, propane and butane and propane / butane mixtures are particularly preferred. The same applies to dimethyl ether.

The amount of blowing agent used in the system according to the invention can vary within wide limits. In general, based on the system according to the invention, it is in the range from 5 to 30% by weight, in particular 7.5 to 15% by weight. Nevertheless, it may be possible to derogate from the above amounts if required by the application.

In order to extend the setting or hardening times, so-called setting retarders ("retarders") - synonymously also sometimes referred to as hydration retardants or hydration inhibitors - may be added to the system according to the invention. Here all known from the prior art setting retarder can be used. For example, such retarders can be used as have been described in the introductory part of the present invention. Particularly preferred are those retardants which can reversibly complex the calcium ions of the settable gypsum.

Examples of preferred setting retarders according to the invention are organic acids and their salts, in particular acrylic acid and methacrylic acid polymers and copolymers, such as (meth) acrylic acid / maleic acid (anhydride) copolymers, tartaric acid and citric acid; Succinimide and aspartate polymers and copolymers; carboxyl-substituted polymers (eg, carboxyl group-containing polymerized amino acids, carboxyl-substituted polymeric sugars, carboxyl-substituted modified polyacrylates, etc.); Phosphates, such as hexamethaphosphate and tetrasodium pyrophosphate; and mixtures of the aforementioned compounds.

The amount of optionally existing retarder can equally vary within wide limits. It should in particular be chosen such that a significant setting retardant effect is effected. In general, the setting retarder, if present, in amounts of 0.1 to 5 wt .-%, in particular 0.5 to 2 wt .-%, based on the inventive system used. Similarly, it is also possible to deviate from the aforementioned amounts, if this should be required by the application.

If the system according to the invention comprises a setting retarder, it should moreover also contain a setting accelerator, which is advantageously added to the system only immediately before or during the application in order to remove the setting-delaying effect of the setting retarder or to accelerate the setting process.

Without wishing to be bound by any particular theory, the ab¬-accelerating effect or the setting-retarding effect of the set retarder can be explained by the fact that the calcium complexes reversibly formed by the set retardants prevent the setting process Addition of Abbindebeschleunigers be resolved so that the previously complexed calcium ions are released again and then can lead with the existing sulfate ions to hardened gypsum.

As setting accelerator known from the prior art as such compounds can be used. In particular, as setting accelerator compounds from the group of aluminum, iron, zinc, alkali and Alkaline earth salts. The setting accelerators are preferably aluminum (III), zinc (II) and iron (III) salts, in particular aluminum, iron and zinc sulfate.

The amounts with which the setting accelerator used according to the invention, if present, can likewise vary within wide ranges. It should in particular be selected such that a significant setting-accelerating effect is effected. In general, the binding accelerator is used in amounts of from 0.01 to 5% by weight, preferably from 0.1 to 0.5% by weight, based on the system according to the invention. Similarly, it is also possible to deviate from the aforementioned amounts, if this should be required by the application.

In order to improve or facilitate the application or application of the foamed gypsum-containing material which can be produced by the system according to the invention, it is advantageous if the system according to the invention also contains so-called film-forming aids - also known as "film-forming aids", "film-forming auxiliaries". or "film former". These are in particular solvents or plasticizers which - added as additives in small amounts - the (minimum) film-forming temperature (MFT) of a polymer dispersion in the desired

Reduce dimensions, so that even at low temperature, a closed film is formed. The film-forming aids in this way support the film formation on the substrate, on which the foamed gypsum-containing material is applied, and thus facilitate the filming of the polymer. In this case, for example, high-boiling solvents due to their low

Evaporation rate practically act as a temporary plasticizer.

The effectiveness of the solvents which can be used as film-forming aids is highly dependent on the particular type of dispersion, ie one and the same solvent lowers the minimum film-forming temperature (MFT) of different polymer dispersions to varying degrees. Unlimited water-miscible solvents, such. As ethanol or ethylene glycol, are as film-forming aids in the present This invention is generally not particularly suitable because it remains in the outer, aqueous phase of a dispersion and does not migrate into the polymer; they also lower the original viscosity of the dispersion, while better suitable film-forming aids according to the invention increase the viscosity as a result of solvation of the polymer particles. Therefore suitable film-forming aids according to the invention, in particular based on solvents or plasticizers, have only limited water miscibility or water solubility.

Examples of film-forming auxiliaries are high-boiling solvents and plasticizers, particularly with boiling points above 200 ⁰ C, preferably above 250 ⁰ C. Examples include glycols and glycol derivatives such. As butyl triglycol and its derivatives, for. B. Butyltrigklykolacetat.

The amount of optionally used film-forming agent can equally vary within wide ranges. In general, it is based on the system according to the invention in the range of 0.1 to 3 wt .-%, in particular 0.5 to 1 wt .-%. Similarly, it is also possible to deviate from the aforementioned amounts, if this should be required by the application.

In order to achieve an improved or easier foamability of the gypsum-containing material based on the settable gypsum together with the organic polymer, it may be advantageous if the system according to the invention additionally contains at least one foam stabilizer.

According to the invention suitable foam stabilizers are, for example, higher alcohols, in particular C ₁₀ -C ₃ o-alcohols, or so-called fatty alcohols, especially _{_C16-Ci8} fatty alcohols, or optionally alkoxylated, in particular ethoxylated higher alcohols and fatty alcohols or fatty amines and their salts (e.g. B. ammonium stearate). Examples of foam stabilizers which are particularly suitable according to the invention are hexadecanol, oleylcetyl alcohol + 5-EO,

Laurylethersulfatnatriumsalz, tallow alcohol + 14-EO and Ci ₆ -Ci ₈ -Fettalkohole. Since ¹ commercially available dispersions, especially aqueous dispersions of organic polymers, as they can be used according to the invention, often contain small amounts of defoamers, the amount of foam stabilizers must be such that it compensates for any defoamers present or repeals their effect.

The amount of foam stabilizers in the system according to the invention can vary within wide limits. In general, the foam stabilizers in amounts of 0.05 to 5 wt .-%, in particular 0.3 to 1, 5 wt .-%, based on the inventive system used. Similarly, it is also possible to deviate from the aforementioned amounts, if this should be required by the application.

Moreover, it may be advantageous if the system according to the invention contains at least one solvent. Here, for example, known per se

Solvents are used, for. As lower hydrocarbons or preferably lower alcohols, such as methanol, ethanol or isopropanol. The use of solvents has the advantage that optionally used as foam stabilizers higher alcohols or fatty alcohols are dissolved in the solvent and thereby can be distributed homogeneously in the dispersion.

The amount of optionally present solvents can equally vary within wide ranges. In general, it is in the range of 0 to 5 wt .-%, in particular 1, 5 to 3 wt .-%, based on the inventive system.

According to a particularly preferred embodiment according to the invention, the system according to the invention for producing the foamed gypsum-containing material advantageously as a so-called two-component system, wherein the two components are brought together only immediately before or during their application, preferably with intensive mixing (eg Shaking, etc.). Various combinations or variants are possible, as the individual components can be arranged in the two components. Irrespective of the individual combinations or variants, setting accelerators on the one hand and setting retarders, on the other hand, are advantageously present in different, in particular separate, ie in particular spatially separated components which are combined only immediately before or during use. Similarly, regardless of the individual combinations or variants, the settable gypsum is generally used together with the setting retarder in one component, and in the other component the setting accelerator is brought into contact with the gypsum and set retarder only immediately before or during use , The component which contains the settable gypsum and / or the component which contains the organic polymer are advantageously present in the form of a preferably aqueous dispersion.

In the following, three possible combinations or variants are discussed by way of example and not limitation.

According to a first variant of the 2-component system, the settable gypsum, the organic polymer which can be foamed with the settable gypsum, the propellant and all other, optionally present, further

Ingredients (especially setting retarders, foam stabilizers, film-forming aids, solvents, etc.) are present in a first component, while the setting accelerator is present in another, second component. Immediately before or during the application of the system according to the invention, the two components are then combined, generally under intimate

Mixing (eg by shaking). For example, the two components of the 2-component system in a closable container, for. As a spray can or an aerosol can, are combined with each other, which has a spray head from which then the foamed gypsum-containing material can be applied. According to a second variant of the 2-component system, in the first component, the organic polymer is present together with the blowing agent and the setting accelerator and in the second component the settable gypsum together with the setting retarder, while the remaining optional ingredients (film forming aids, , Foam stabilizers, solvents, etc.) may be present in the first and / or in the second component.

According to a third variant of the 2-component system, in the first component of the system according to the invention, the organic polymer may be present together with the setting accelerator, while in the second component the settable gypsum is present together with the blowing agent and optionally the setting retarder, whereas the optionally present, other further ingredients (film-forming agents, foam stabilizers, solvents, etc.) may be present in the first and / or in the second component.

In addition, many other variants are possible.

In all variants of the embodiment designed according to the invention as a 2-component system, the components which comprise the settable gypsum and / or the organic polymer are advantageously present as dispersions, preferably as aqueous-based dispersions.

The following Tables 1 to 3 schematically represent the three previously described variants of the system according to the invention in its construction as a two-component system: Table i: "Variant 1"

Table 2: "Variant 2"

Table 3: "Variant 3"

According to a typical embodiment of the invention, the system according to the invention can be designed as follows:

A water-based polymer dispersion having a foam stabilizer, Plaster retarder (carboxyl group-containing polymers, such as. For example Sokalan ^® CP5 ex BASF AG) and abbindefähigem gypsum added ( "mixture A"). Due to the gypsum retarder, the gypsum does not yet bind in the dispersion. A stable mixture of dispersion and settable gypsum is obtained. This "mixture A" is placed in an aerosol can and mixed with propellant (for example propane / butane or dimethyl ether). If an accelerator (eg based on aluminum or iron (III) salts) is added just before foaming or during foaming (eg 2-component can, second nozzle, accelerator in powder form in order tubes) , simple mixing, etc.), so you get a foam that dries quickly due to the setting of the gypsum. By the amount of gypsum can be divided in addition to the drying time and the hardness and strength of the foam.

A number of advantages are associated with the system according to the invention for producing a foamed gypsum-containing material:

With the system according to the invention gypsum-containing materials can readily be foamed. In this way, so-called foamed gypsum materials can be used ("Gypsum foams") produce that harden or dry relatively quickly. The curing or drying times are generally less than 24 hours.

The applied after application, generally water-based "gypsum foam" dries relatively quickly, especially within a few hours, and is dimensionally stable due to the set gypsum and has relatively high strengths on. By the amount of gypsum can - in addition to the drying time - also set after drying or setting hardness and strength of the produced "gypsum foam" set.

Another advantage of the inventively produced, foamed gypsum-containing

Materials is the fact that they can be removed directly or shortly after application readily with water, for. B. are wipeable, are. Incorrectly applied material can easily be removed in this way easily.

Due to the special selection of polymers and blowing agents in their combination and the special quantitative adaptation of the individual components, dimensionally stable foams can be produced. In particular, no or no appreciable post-expansion or no or no appreciable shrinkage of the foamed material is observed. As a result, the foamed volume can be set or controlled relatively precisely.

The system according to the invention is generally water-based and therefore very environmentally friendly. Since only harmless ingredients or ingredients are used, in particular no organic isocyanates, it is harmless in its application and therefore not subject to labeling.

Due to the selection of the individual constituents in their respective quantitative ratios, in particular due to the specially selected propellant, it is possible to achieve suitable densities, generally in the range from 20 to 100 g / l, preferably from 30 to 50 g / l, of the foamed gypsum-containing material , Another object of the present invention - according to a second aspect of the present invention - is a method for producing a foamed gypsum-containing material or a method for foaming a gypsum-containing material, wherein the settable gypsum, as defined above, with at least one together with the settable gypsum foamable organic polymer, as defined above, by means of at least one suitable propellant, optionally in the presence of at least one setting retarder, at least one setting accelerator and optionally further ingredients, in particular foam stabilizers, film-forming agents, solvents and the like, to a gypsum-containing material ("gypsum foam") foaming, followed by drying and / or setting (curing).

For further details of the method according to the invention, reference may be made to the above statements with regard to the system according to the invention, which apply correspondingly to the method according to the invention.

Another object of the present invention - according to a third aspect of the present invention - is the foamed gypsum-containing material produced with the system according to the invention or obtainable by the process according to the invention and subsequently dried and set.

The present invention thus relates to a foamed gypsum-containing material which comprises set gypsum together with an organic polymer previously foamed with the gypsum and, if appropriate, further ingredients, in particular as defined above (for example setting retarder, setting accelerator,

Foam stabilizers, film-forming aids, solvents, etc.), preferably in homogeneous distribution. Such foamed gypsum-containing materials are dimensionally stable and have in particular bulk densities in the range of 20 to 100 g / l, preferably 30 to 50 g / l, on.

Finally, another object of the present invention - according to a fourth aspect of the present invention - a container, in particular a for Foaming suitable can ("aerosol can") containing the inventive system described above.

Further embodiments, modifications and variations and advantages of the present invention will be readily apparent to those skilled in. When reading the description and feasible, without departing from the scope of the present invention.

The present invention will be illustrated by the following embodiments, which are not limitative of the present invention.

EXAMPLES

Example 1:

21, 57 g of the dispersion Primax ^® 310 (Rohm & Haas, acrylate polymer, solids content: 50.6%, viscosity: 135 mPas, pH <4) with 1, 5 g of a 25% solution of Lanette O ^® (Fa. Cognis, C ₆ -C ₈ fatty alcohol foam stabilizer) in isopropanol, 0.5 g of butyl triglycol, 0.5 g Texapon ^® NSO (Fa. Cognis, Laurylethersulfatnatriumsalz,

Foam stabilizer), and 1, 9 g Sokalan ^® CP5 (BASF AG, offset setting retarder based on carboxyl-containing polymers) and mixed. 19.03 g of alpha-30 gypsum (Südharzer gypsum works) are stirred into this mixture. Just before filling into the aerosol can, the total mixture is mixed with 1.2 g of a 13% strength aluminum sulfate solution. After the aluminum sulfate has been stirred in, the total mixture is filled into an aerosol can; the can is closed and 5 g propane / butane propellant are poured into the can. After vigorous shaking, the mixture is immediately foamed. A foam is obtained which has dried through within 15 hours. Example 2:

21, 57 of the dispersion Acronal ^® 290D (50%, viscosity: 1000 mPas, pH: BASF AG, styrene / butyl acrylate polymer, solids content 8.2) g of 1, 5 g of a 25% solution of Lanette O ^® (Fa. Cognis) in isopropanol, 0.5 g of butyl triglycol, 0.5 g Texapon ^® NSO (Fa. Cognis), and 1, 9 g Sokalan ^® CP5 (BASF AG) were added and mixed. 19.03 g of alpha-30 gypsum (Südharzer gypsum works) are stirred into this mixture. Shortly before filling into the aerosol can, the total mixture is mixed with 1, 2 g of a 13% solution of aluminum sulfate. After the aluminum sulfate has been stirred in, the total mixture is filled into an aerosol can; the can is closed and 5 g propane / butane propellant are poured into the can. After vigorous shaking, the mixture is immediately foamed. A foam is obtained which has dried through within 14 hours.

Comparative Example 1

42.5 g of the dispersion Primax ^® 310 (Rohm & Haas) are mixed with 1, 5 g of a 25% solution of Lanette ^® O (Fa. Cognis) in isopropanol, 0.5 g and 0.5 g of butyl triglycol

Texapon ^® NSO (Fa. Cognis) was added and mixed. The total mixture is filled into an aerosol can and, after closing the can, 5 g of propane / butane propellant are poured into the can. After vigorous shaking, the mixture is filled with foam. This gives a foam that takes more than 24 hours to dry.

Comparative Example 2:

42.5 g of the dispersion Acronal ^® 290D (BASF AG) are reacted with 1, 5 g of a 25% solution of Lanette ^® O (Fa. Cognis) in isopropanol, 0.5 g and 0.5 g of butyl triglycol

Texapon ^® NSO (Fa. Cognis) was added and mixed. The total mixture is filled into an aerosol can, and after sealing the can, 5 g of the propellant Propane / butane filled in the can. After vigorous shaking, the mixture is filled with foam. This gives a foam that takes more than 24 hours to dry.

Claims

claims:

A system for producing a foamed gypsum-containing material, in particular in the form of an aqueous-based dispersion, wherein the system

(i) settable gypsum,

(ii) at least one organic polymer foamable together with the settable gypsum,

(iii) at least one propellant,

(iv) optionally at least one set retardant and

(v) optionally at least one setting accelerator

includes.

2. System according to claim 1, characterized in that the gypsum in the form of a settable calcium sulfate, preferably in the form of a settable hydrated calcium sulfate or in the form of a settable anhydrous calcium sulfate, in particular anhydrite, particularly preferably in the form of a calcium sulfate hemihydrate.

3. System according to claim 1 or 2, characterized in that the organic polymer together with the gypsum provides a curable foamed mass.

4. System according to one or more of the preceding claims, characterized in that the amount of settable gypsum 5 to 70 wt .-%, in particular 10 to 60 wt .-%, preferably 25 to 40 wt .-%, based on the

System, is.

5. 'i System according to one or more of the preceding claims, characterized in that the organic polymer is a water-soluble or water-dispersible polymer and / or that the organic polymer is in dissolved or dispersed form, in particular in the form of an aqueous dispersion or solution ,

6. System according to one or more of the preceding claims, characterized in that the organic polymer has film-forming properties and / or that the organic polymer number average molecular masses M _n > 100,000, in particular M _n > 500,000, preferably M _n > 750,000, more preferably M _n > 1,000,000.

7. System according to one or more of the preceding claims, characterized in that the polymer is selected from the group of polymers and / or copolymers based on:

Acrylic and methacrylic acids and their esters, amides and nitriles;

Maleic acids and their anhydrides and esters;

styrenes;

• vinyl acetates;

• vinyl chloride and vinylidene chloride;

Vinyl esters of versatic acid, in particular VeoVa 9, 10 and 11;

vinyl ethers; reactive monomers, in particular methylolacrylamide;

silane-containing monomers, such as vinylalkoxysilanes;

and or

• vinyl pivalate.

8. System according to one or more of the preceding claims, characterized in that the organic polymer is selected from the group of polyvinyl alcohols, polyvinylpyrrolidones, polyethylene glycols and hydroxyethyl cellulose and mixtures thereof.

9. System according to one or more of the preceding claims, characterized in that the polymer is a polyurethane-based polymer, in particular in the form of an aqueous-based polyurethane dispersion.

10. System according to one or more of the preceding claims, characterized in that the amount of organic polymer, based on the

System, 5 to 85 wt .-%, in particular 20 to 75 wt .-%, preferably 30 to 70 wt .-%, and / or that the organic polymer is in the form of a dispersion, in particular in the form of an aqueous dispersion, wherein the amount of in particular aqueous, the organic polymer-containing dispersion is 20 to 90 wt .-%, in particular 30 to 75 wt .-%, preferably 40 to 70 wt .-%, based on the system, in particular wherein the dispersion Polymer dispersion having a solids content (polymer content) of 20 to 80 wt .-%, in particular 30 to 70 wt .-%, preferably 40 to 65 wt .-%, based on the dispersion, is present.

11. System according to one or more of the preceding claims, characterized in that the blowing agent with respect to the organic polymer at least substantially or at most only slightly swelling acts, in particular wherein from the organic polymer at most 0 to 25 wt .-%, in particular at most 1 to 20 wt .-%, preferably at most 5 to 15 wt .-%, of the propellant is absorbable ,

12. System according to one or more of the preceding claims, characterized in that the blowing agent is liquid at room temperature under atmospheric pressure and / or that the blowing agent is emulsifiable in the aqueous phase.

13. System according to one or more of the preceding claims, characterized in that the propellant is selected from the group of alkanes, in particular propane, butane and isobutane and mixtures of propane and butane; Ethers, in particular dimethyl ether; fluorinated hydrocarbons, in particular 1, 1, 1, 2-tetrafluoroethane and 1, 1-difluoroethane; carbon dioxide; Nitrous oxide (nitrous oxide,

N ₂ O); and mixtures thereof, preferably from the group of propane, butane, propane / butane mixtures, isobutane, dimethyl ether and mixtures thereof.

14. System according to one or more of the preceding claims, characterized in that the amount of blowing agent, based on the system, 5 to 30

Wt .-%, in particular 7.5 to 15 wt .-%, is.

15. System according to one or more of the preceding claims, characterized in that the setting retarder is selected from compounds which can complex the calcium ions of settable gypsum.

16. System according to one or more of the preceding claims, characterized in that the setting retarder is selected from the group of organic acids and their salts, in particular acrylic acid and methacrylic acid polymers and copolymers, such as (meth) acrylic acid / maleic acid (anhydride ) Copolymers, tartaric acid and citric acid; Succinimide and aspartate polymers and copolymers; with carboxyl groups substituted polymers; Phosphates, such as hexametaphosphate and tetrasodium pyrophosphate.

17. System according to one or more of the preceding claims, characterized in that the amount of setting retarder 0.1 to 5 wt .-%, in particular 0.5 to 2 wt .-%, based on the system.

18. System according to one or more of the preceding claims, characterized in that the setting accelerator is selected from compounds which are able to cancel the setting-delaying effect of setting retarders.

19. System according to one or more of the preceding claims, characterized in that the setting accelerator is selected from the group of aluminum, iron, zinc, alkali and alkaline earth salts, in particular

Aluminum (III), zinc (II) and iron (III) salts, especially aluminum, iron and zinc sulfate.

20. System according to one or more of the preceding claims, characterized in that the amount of setting accelerator in amounts of 0.01 to

5 wt .-%, preferably 0.1 to 0.5 wt .-%, based on the system.

21. System according to one or more of the preceding claims, characterized in that the system also contains at least one further constituent, in particular selected from the group of the following

Links:

(vi) at least one film-forming agent, in particular in amounts of from 0.1 to

3 wt .-%, preferably 0.5 to 1 wt .-%, based on the system; and or (vii) at least one foam stabilizer, in particular in amounts of from 0.05 to 5% by weight, preferably from 0.3 to 1.5% by weight, based on the system; and or

(viii) at least one solvent, in particular in amounts of 0 to 5% by weight.

%, preferably 1, 5 to 3 wt .-%, based on the system.

22. System according to one or more of the preceding claims, characterized in that the system is present as a 2-component system

23. System according to claim 22, characterized in that setting accelerator on the one hand and setting retarder on the other hand are present in different, in particular separate components, which are brought together only immediately before or during use, and / or that the settable gypsum is present together with the setting retarder in the same component while in the other, second component, the setting accelerator is present, which is brought together with the gypsum and the set retarder only immediately before or during use, and / or that the component containing the settable gypsum and / or the component which contains the organic polymer, in the form of a preferably aqueous dispersion is present / present.

24. A process for producing a foamed gypsum-containing material, wherein the settable gypsum together with at least one foamable organic polymer by means of at least one blowing agent, optionally in

Presence of at least one setting retarder and / or at least one setting accelerator and / or optionally further ingredients, in particular foam stabilizers, film-forming aids, solvents and the like, is foamed to a gypsum-containing material.

25 ^' I With the system according to claims 1 to 23 produced or by the method according to claim 24 available, subsequently dried and set, foamed gypsum-containing material.

26. Foamed gypsum-containing material containing dried and ab¬ bound gypsum together with a previously foamed with the gypsum organic polymer and optionally other ingredients, as defined above, preferably in a homogeneous distribution.

27. A foamed gypsum-containing material according to claim 25 or 26, characterized in that it is dimensionally stable and / or that it has a bulk density in the range of 20 to 100 g / l, preferably 30 to 50 g / l.

28. Container, in particular in the form of a can suitable for foaming ("aerosol can"), comprising the system according to one of claims 1 to 23.