WATER-BASED INTUMESCENT ADHESIVE

Description

[0001] The present invention relates to intumescent adhesives in the form of aqueous dispersions for the production of composites with good thermal insulation properties and high fire protection performance.

[0002] For thermal insulation purposes, free-flowing insulation materials have been installed in building cavities for many years. Insulation materials with low thermal conductivity are particularly preferred, allowing for the highest possible insulation performance with minimal insulation thickness. At the same time, high free-flowing insulation materials are important so that all cavities can be filled quickly and completely. Furthermore, after filling the cavities, further settling due to building vibrations should be avoided, thus preventing the formation of uninsulated building sections.

[0003] These requirements are met very well with spherical beads made of expanded polystyrene (EPS). EPS beads are available in various diameter ranges and bulk densities, for example, under the name Neopor. Beads used for this purpose typically have an outer diameter of 3–5 mm and a bulk density of 10–14 g / l. Such beads are also available in certain versions with improved fire performance. These insulation materials fulfill two essential basic requirements for building products: thermal insulation and fire protection.

[0004] A major disadvantage of cavities insulated with free-flowing insulation materials is that when a cavity filled in this way is opened, for example when a window is to be installed in a building component, the thermal insulation will trickle out due to its excellent flowability.

[0005] This disadvantage has so far been remedied by mixing the insulation particles with an adhesive when inserting the EPS beads. This adhesive hardens after the beads have been positioned and thus prevents the insulation beads from subsequently trickling out.

[0006] For this purpose, commercially available aqueous polymer dispersions have previously been used as adhesives. Polyvinyl alcohol or polyvinyl acetate dispersions, for example, are particularly suitable. For bonding, 5-7 kg of these dispersions, usually at 50%, are used per cubic meter of EPS beads.

[0007] However, the currently used flammable adhesives have the disadvantage of impairing the fire behavior of the insulation materials. Even EPS beads, whose fire behavior meets construction product class E according to EN 13501-1 without adhesive, no longer meet this requirement after bonding with the aforementioned dispersions.

[0008] The publication AU-A-50265 / 93 attempts to compensate for the disadvantage of flammable adhesives by adding flame retardants. However, high concentrations of the flame retardants mentioned therein are required to achieve any significant effect, which in turn complicates the dosing of the adhesive / flame retardant mixtures.

[0009] The document WO2012168347A1 (Akzo Nobel Chemicals International BV) discloses a powdered additive for improving the adhesion of building material compositions, wherein the additive comprises a polysaccharide and a plasticizer selected from the group of fully or partially saponified polyvinyl alcohols and their derivatives. However, this additive does not exhibit any fire-retardant properties. The document WO2012123772A1 (Rudolf Hensel GmbH), in contrast, discloses an aqueous fire-protection coating that forms insulating layers. In one embodiment, this coating comprises, in addition to a silicone resin emulsion as a binder, an aqueous organic polymer dispersion, carbohydrates, and an acid-donating substance. Despite the presence of a silicone resin as a binder to improve the mechanical stability of the insulating layer, the composition is used only as a coating.

[0010] The publication US 2009 / 0246445 A1 describes how lumpy recycled EPS is first coated with known intumescent fire-protection coatings and dried. The prepared particles are then bonded together with a binder to form insulation packages, resulting in insulation materials with improved fire performance.

[0011] EPS beads can also be bonded to known intumescent coatings, thereby achieving significantly improved fire behavior. Such intumescent formulations are known to those skilled in the art and are described, for example, in EP 0582 604 B1. However, in order to maintain the flowability of the adhesive-coated EPS beads and keep the adhesive costs within an acceptable range, these coatings must be heavily diluted with water.

[0012] When formulating intumescent coatings, great importance is placed on using water-insoluble active ingredients wherever possible to increase their durability under atmospheric influences. However, this proves to be a disadvantage with the aforementioned high dilution, as it leads to rapid sedimentation of the water-insoluble substances, which has previously made the dosing of a homogeneous intumescent adhesive virtually impossible. Furthermore, formulations containing water-insoluble solid particles frequently lead to blockages in the lines during application, particularly in the spray nozzles used to distribute the adhesive onto the EPS beads.

[0013] An important task in the development of improved formulations is therefore to develop fire-retardant, intumescent adhesives whose ingredients are all water-soluble. Such formulations avoid the processing difficulties previously observed due to the adhesive's lack of homogeneity, either during dilution or during application.

[0014] This object is surprisingly achieved by the aqueous compositions described below, which are preferably present as aqueous dispersions. The aqueous dispersions according to the invention contain exclusively water-soluble components and nevertheless fulfill the desired fire protection properties, thus providing, for the first time, high-performance intumescent adhesives made from aqueous dispersions for this purpose.

[0015] Therefore, in particular in a first aspect of the invention, an aqueous dispersion is claimed which comprises the following components: a) at least one binder in dispersion form b) at least one water-soluble salt of phosphoric acid c) at least one water-soluble carbohydrate which is a disaccharide d) optionally at least one water-soluble ammonium salt and / or at least one amino compound, wherein the at least one binder in dispersion form comprises a stabilized dispersion containing a copolymer of vinyl acetate and a vinyl ester of another long-chain carboxylic acid.

[0016] In a preferred embodiment, the at least one binder in dispersion form comprises a stabilized dispersion containing a copolymer obtained by copolymerization of vinyl acetate and a vinyl ester of neodecanoic acid.

[0017] In a further preferred embodiment, the at least one binder is present in dispersion form in an amount of 5 to 40 parts by weight, preferably 10 to 20 parts by weight, based on the aqueous dispersion.

[0018] In a further preferred embodiment, the at least one water-soluble salt of phosphoric acid comprises an ammonium salt of phosphoric acid, preferably monoammonium phosphate.

[0019] In a further preferred embodiment, the amount of monoammonium phosphate is 5 to 30 parts by weight, preferably 10 to 20 parts by weight, based on the aqueous dispersion.

[0020] In a further preferred embodiment, the at least one water-soluble carbohydrate, which is a disaccharide, is present in an amount of 2 to 20 parts by weight, preferably 3 to 10 parts by weight, based on the aqueous dispersion.

[0021] In a further preferred embodiment, the at least one water-soluble carbohydrate which is a disaccharide comprises sucrose.

[0022] In a further preferred embodiment, the at least one water-soluble ammonium salt and / or the at least one amino compound is present in an amount of 0 to 10 parts by weight, preferably 2 to 5 parts by weight, based on the aqueous dispersion.

[0023] In a further preferred embodiment, the at least one water-soluble ammonium salt and / or the at least one amino compound contains urea.

[0024] In a further aspect of the present invention, a method for producing a fire-protected insulating material is claimed, comprising the steps: Mixing an expanded styrene polymer with the aqueous dispersion according to the invention, shaping the resulting mixture, and solidifying the mixture, preferably by drying the mixture.

[0025] In a further aspect of the present invention, a composite material is claimed comprising an expanded styrene polymer and an intumescent adhesive, obtainable by mixing the expanded styrene polymer with the aqueous dispersion according to the invention, shaping the resulting mixture and then drying it.

[0026] In a further aspect of the present invention, the use of the aqueous dispersion according to the invention as an intumescent adhesive is claimed, characterized in that the aqueous dispersion is mixed as a liquid adhesive with an insulating material, is shaped and then dried in order to obtain a fire-protected insulating material.

[0027] In a further preferred embodiment, the foam material comprises expanded polystyrene and the insulating material is used for insulating double-shell masonry.

[0028] The present invention is described in more detail below: The term "dispersion" as used herein refers to dispersed polymer droplets in an aqueous phase.

[0029] The term "stabilized dispersion" as used here refers to homogeneous dispersions that are compatible with salts dissolved in water.

[0030] The term "in dispersion form" or "in dispersed form" is used in the present invention for stabilized dispersions.

[0031] The term "binder" as used here refers to stabilized dispersions.

[0032] The term "water-soluble" is used in the present invention for various components of the claimed aqueous adhesive. The term "water solubility" therefore refers to the dissolving behavior of individual components and defines both dissolved and stably dispersed components in the adhesive.

[0033] The term "intumescent adhesive" is familiar to those skilled in the art and refers to a sticky or adhesive composition or material that has additional fire-retardant properties. The intumescent adhesive has a sticky or adhesive component that chemically cures and / or physically sets. Preferably, the solidification of a polymer component or an aqueous dispersion occurs by drying the solvent, particularly water. The intumescent adhesive exerts its fire-retardant effect under the influence of heat, particularly under the influence of fire, by significantly increasing its volume and / or by releasing an acid and carbonizing an organic component, forming a fire-retardant protective layer of ash or coal, preventing further scorching, burning, ignition, or spread of the fire.

[0034] In the present invention, the term "fire protection" or "fire-protected" refers to the property of a product or composite material to fully meet the fire protection requirements of fire protection class E according to EN 13501-1.

[0035] The aqueous dispersions according to the invention contain as an essential component a dispersion binder, or binder in dispersion form, which ensures the adhesive effect or stickiness of the aqueous dispersion.

[0036] The dispersion binder must exhibit high salt tolerance. To achieve this property, the present invention uses appropriately stabilized dispersions with copolymers of vinyl acetate and a vinyl ester of another long-chain carboxylic acid. Accordingly, the binder in dispersion form is preferably a free-radical emulsion polymer obtained by free-radical polymerization of at least two monomers. Suitable polymerization methods, such as bulk, solution, suspension, or emulsion polymerization, are known to those skilled in the art.

[0037] The main monomer is vinyl acetate. The comonomer is a vinyl ester of a long-chain carboxylic acid, such as neodecanoic acid or Versatic acid. The preferred comonomers of the vinyl esters of neodecanoic acid are isomeric mixtures with 10 carbon atoms and are commercially available (VeoVa; Hexion Specialty Chemicals, Ohio, USA). They can be used in this form to prepare the binder in dispersion form for the aqueous dispersions according to the invention containing the preferred copolymers of vinyl acetate and vinyl esters of neodecanoic acid.

[0038] The binder in dispersion form can be obtained as a copolymer by solution polymerization followed by dispersion in water or, particularly preferably, by emulsion polymerization, so that the aqueous binder is present as a copolymer dispersion.

[0039] Emulsion polymerization can be carried out batchwise, with or without the use of seed latices, with initial charging of all or individual components of the reaction mixture, or preferably with partial initial charging and subsequent metering of some or all of the individual components of the reaction mixture, or by the metering method without initial charging. In emulsion polymerization, the monomers can be polymerized as usual in the presence of a water-soluble initiator and an emulsifier, preferably at 30 to 95°C. Suitable initiators include sodium, potassium, and ammonium persulfate, tert-butyl hydroperoxides, water-soluble azo compounds, or redox initiators such as H2O2 / ascorbic acid.

[0040] Examples of suitable emulsifiers include alkali salts of long-chain fatty acids, alkyl sulfates, alkyl sulfonates, alkylated arylsulfonates, or alkylated biphenyl ether sulfonates. Other suitable emulsifiers include reaction products of alkylene oxides, particularly ethylene or propylene oxide, with fatty alcohols, fatty acids, phenol, or alkylphenols.

[0041] In the case of aqueous secondary dispersions, the copolymer is first prepared by solution polymerization in an organic solvent and then dispersed in water without the use of an emulsifier or dispersing agent by adding salt formers, e.g., ammonia, to copolymers containing carboxylic acid groups. The organic solvent can be distilled off. The preparation of aqueous secondary dispersions is known to the person skilled in the art and is described, for example, in DE-A-37 20 860. Regulators can be used during the polymerization to adjust the molecular weight. Suitable examples include -SH-containing compounds such as mercaptoethanol, mercaptopropanol, thiophenol, and thioglycolic acid esters.

[0042] In the preferred embodiments, the at least one binder is present in dispersion form in an amount of 5 to 40 parts by weight, preferably 7 to 25 parts by weight, particularly preferably 10 to 20 parts by weight, and most preferably 12 to 16 parts by weight, based on the total amount of the aqueous dispersion.

[0043] As water-soluble salts of phosphoric acid, compounds capable of releasing phosphoric acid and / or oligophosphoric acid and / or polyphosphoric acid can be used in the present invention. Such substances are, in particular, ammonium phosphates, i.e., ammonium salts of phosphoric acid, oligophosphoric acid, and / or polyphosphoric acid, with ammonium salts of phosphoric acid being preferred. Particularly preferred within the scope of the present invention are monoammonium phosphate, diammonium phosphate, or mixtures of these compounds. These substances can preferably be present in condensed form.

[0044] The at least one water-soluble phosphoric acid salt is present in an amount or weight of 5 to 30 parts by weight, particularly preferably 7 to 27 parts by weight, and most preferably 10 to 20 parts by weight. 12 to 17 parts by weight are most preferred, with these figures referring to the amount of water-soluble phosphoric acid salt relative to the total amount of the adhesive.

[0045] Water-soluble carbohydrates are generally considered to be carbon-containing substances with esterifiable hydroxyl groups. Examples include carbohydrates, starch, sugar, and cellulose, but especially water-soluble carbohydrates in the narrower sense, i.e., carbohydrates in the sense of saccharides.

[0046] Carbohydrate in the sense of the present invention is therefore particularly referred to as biomolecules which consist of carbon, hydrogen and oxygen and typically have a hydrogen-oxygen ratio of 2:1 and therefore correspond to the empirical formula C m (H 2 O) n , in which m can differ from n, but does not have to.

[0047] Particularly preferred are polyhydric alcohols or mixtures thereof, i.e., oligosaccharides, of which tetrahydric alcohols, such as pentaerythritol, can be used. Dipentaerythritol is another preferred substance.

[0048] However, monosaccharides and disaccharides are most preferred as water-soluble carbohydrates. Monosaccharides have a chain of three carbon atoms as their basic structure and additionally contain a carbonyl group and a hydroxyl group. Monosaccharides suitable for the present invention are glucose, fructose, galactose, erythrose, threose, arabinose, xylose, mannose, and the like. Glucose, fructose, mannose, and galactose are particularly preferred, with glucose being the most preferred monosaccharide.

[0049] Disaccharides are formed by linking two monosaccharides or are at least composed of them. Suitable disaccharides include, for example, cellobiose, lactose, trehalose, sucrose, maltose, and the like. Sucrose is a particularly preferred water-soluble carbohydrate disaccharide within the scope of the present invention.

[0050] The at least one water-soluble carbohydrate is present in an amount or weight of 2 to 20 parts by weight, particularly preferably 3 to 18 parts by weight, and most preferably 3 to 10 parts by weight. 3 to 8 parts by weight are most preferred, with these figures referring to the amount of water-soluble carbohydrate relative to the total amount of the adhesive.

[0051] Within the scope of the present invention, at least one additional water-soluble ammonium salt and / or at least one additional amino compound may optionally be present in the aqueous dispersion according to the present invention. This additional component in the aqueous dispersions of the present invention is therefore optional.

[0052] Within the scope of the present invention, at least one additional water-soluble ammonium salt and / or at least one additional amino compound may optionally be present in the aqueous dispersion according to the present invention. This additional component in the aqueous dispersions of the present invention is therefore optional. Preferred ammonium salts or amino compounds that can be used are monoammonium phosphate, urea, biuret, guanidine, melamine, and ammonium sulfate. Monoammonium phosphate is very particularly preferred. Another particularly preferred water-soluble ammonium salt or a particularly preferred additional amino compound within the scope of the present invention is urea.

[0053] The at least one water-soluble ammonium salt or the at least one additional amino compound is present in an amount or weight of 0 to 12 parts by weight, particularly preferably 0 to 10 parts by weight, and most preferably 0 to 8 parts by weight. Most preferred are 1 to 7 parts by weight, with these figures referring to the amount or weight of water-soluble ammonium salt and / or amino compound relative to the total amount of the adhesive.

[0054] The aqueous dispersions according to the invention can optionally contain, in addition to the components described above (binder in dispersion form, wherein the at least one binder in dispersion form is a stabilized dispersion comprising a copolymer of vinyl acetate and a vinyl ester of another long-chain carboxylic acid, a water-soluble salt of phosphoric acid, a water-soluble carbohydrate which is a disaccharide, and the optional water-soluble ammonium salt and / or amino compound), further auxiliaries. As optional auxiliaries, the aqueous dispersions according to the invention can also additionally contain stabilizers, defoamers, thickeners, thixotropic agents, wetting agents, defoamers, dyes, and / or preservatives, the latter in particular to improve resistance to microorganisms and the like, and thereby further increase the stability and storage life of the corresponding products.

[0055] Particularly suitable aqueous dispersions according to the invention have the following composition, based on 100 parts by weight of the adhesive: Preferred aqueous dispersion A): 7 to 25 parts by weight of at least one binder in dispersion form; 7 to 27 parts by weight of at least one water-soluble salt of phosphoric acid; 3 to 17 parts by weight of at least one water-soluble carbohydrate; 0 to 12 parts by weight of at least one water-soluble ammonium salt and / or at least one amino compound; Preferred aqueous dispersion B): 10 to 20 parts by weight of at least one binder in dispersion form; 10 to 20 parts by weight of at least one water-soluble salt of phosphoric acid; 4 to 12 parts by weight of at least one water-soluble carbohydrate; 0 to 10 parts by weight of at least one water-soluble ammonium salt and / or at least one amino compound; Preferred aqueous dispersion C): 12 to 16 parts by weight of at least one binder in dispersion form; 12 to 17 parts by weight of at least one water-soluble salt of phosphoric acid;5 to 8 parts by weight of at least one water-soluble carbohydrate; 0 to 7 parts by weight of at least one water-soluble ammonium salt and / or at least one amino compound; ;

[0056] In the above preferred compositions A) to C), further auxiliaries, as described here, may optionally also be present in the aqueous dispersions according to the invention.

[0057] The amount of auxiliaries is preferably in the range from 0 to 3 parts by weight, based on the total amount of the aqueous dispersion, this information also applying to the preferred aqueous dispersions A), B) and C).

[0058] The solids content of the aqueous dispersions according to the invention is in the range of 20 to 40 parts by weight, preferably 24 to 35 parts by weight, particularly preferably 26 to 33 parts by weight, with the remaining portion being water. The aqueous dispersions according to the invention preferably contain no organic solvents.

[0059] In the present invention, a foam material is generally used as the preferred insulating material. The foam material is preferably in particle form. Polymer foam particles made of thermoplastic polymers can be used as foam particles, in particular. Styrene polymers are particularly suitable for this purpose.

[0060] According to the invention, the term "styrene polymer" encompasses polymers based on styrene, alpha-methylstyrene, or mixtures of styrene and alpha-methylstyrene. Preferred styrene polymers are crystal-clear polystyrene (GPPS), high-impact polystyrene (HIPS), anionically polymerized polystyrene or high-impact polystyrene (A-IPS), styrene-alpha-methylstyrene copolymers, acrylonitrile-butadiene-styrene polymers (ABS), styrene-acrylonitrile copolymers (SAN), acrylonitrile-alpha-methylstyrene copolymers (AMSAN), acrylonitrile-styrene-acrylic esters (ASA), methyl acrylate-butadiene-styrene (MBS), methyl methacrylate-acrylonitrile-butadiene-styrene (MABS) polymers, or mixtures thereof or with polyphenylene ether (PPE). Styrene polymers according to the invention are based on at least 50 parts by weight of styrene and / or alpha-methylstyrene monomers. This applies analogously to the styrene content in SAN, AMSAN, ABS, ASA, MBS, and MABS (see below).Styrene polymers according to the invention are based on at least 50 parts by weight of styrene and / or alpha-methylstyrene monomers.

[0061] To improve the mechanical properties or the temperature resistance, the styrene polymers mentioned can be blended, optionally with the use of compatibilizers, with thermoplastic polymers such as polyamides (PA), polyolefins such as polypropylene (PP) or polyethylene (PE), polyacrylates such as polymethyl methacrylate (PMMA), polycarbonate (PG), polyesters such as polyethylene terephthalate (PET) or polybutylene terephthalate (PBT), polyether sulfones (PES), polyether ketones, polyether sulfides (PES) or mixtures thereof in proportions of up to a maximum of 30 parts by weight, preferably in the range of 1 to 10 parts by weight, based on 100 parts by weight of the polymer melt.Furthermore, blends in the above-mentioned quantity ranges are also possible with, for example, hydrophobically modified or functionalized polymers or oligomers, rubbers such as polyacrylates or polydienes, such as styrene-butadiene block copolymers, or biodegradable aliphatic or aliphatic / aromatic copolyesters. Suitable compatibilizers include maleic anhydride-modified styrene copolymers, epoxy-containing polymers, or organosilanes.

[0062] Particularly preferred foams according to the invention are those containing or consisting of polystyrene, in particular the commercially available types Neopor ®<, Styropor ®< and Peripor ®< (all from BASF SE, Ludwigshafen, Germany).

[0063] Particularly suitable are expanded styrene polymers (EPS), preferably expanded styrene polymers with a molecular weight Mw in the range of 120,000 to 400,000 g / mol, particularly preferably in the range of 180,000 to 300,000 g / mol, measured by gel permeation chromatography according to DIN 55672-1 with refractometric detection (RI) against polystyrene standards. Due to molecular weight reduction due to shear and / or temperature effects, the molecular weight of the expanded polystyrene is generally approximately 10,000 g / mol lower than the molecular weight of the polystyrene used.

[0064] In the production of polystyrenes, polymerization takes place, for example, by bulk polymerization, solution polymerization, or by emulsion, suspension, or dispersion polymerization. Suspension polymerization is preferred.

[0065] In suspension polymerization, styrene alone is the preferred monomer. However, up to 20% of its weight can be replaced by other ethylenically unsaturated monomers such as alkylstyrenes, divinylbenzene, acrylonitrile, 1,1-diphenyl ether, or alpha-methylstyrene. Otherwise, the monomers from which the preferred polymers are obtainable are preferred.

[0066] The particle foam component according to the invention is generally produced from a polymer melt.

[0067] Polymer recyclates of the aforementioned thermoplastic polymers, in particular styrene polymers and expanded styrene polymers (EPS), can also be admixed to the polymer melt in amounts that do not significantly impair their properties, generally in amounts of a maximum of 50 parts by weight, in particular in amounts of 1 to 20 parts by weight, based on 100 parts by weight of the total styrene polymer. Furthermore, conventional additives such as nucleating agents, fillers, plasticizers, soluble and insoluble inorganic and / or organic dyes and pigments, for example IR absorbers such as carbon black, flake graphite, or aluminum powder, can be added to the polymer melt together or separately, for example via mixers or side extruders. The dyes and pigments are generally added in amounts ranging from 0.01 to 30 parts by weight, preferably from 1 to 5 parts by weight, based on 100 parts by weight of the total styrene polymer.For homogeneous and microdispersed distribution of the pigments in the styrene polymer, it may be advantageous, particularly for polar pigments, to use a dispersing agent, for example, organosilanes, epoxy-containing polymers, or maleic anhydride-grafted styrene polymers. Preferred plasticizers are mineral oils and phthalates, which can be used in amounts of 0.05 to 10 parts by weight, based on 100 parts by weight of the total styrene polymer.

[0068] The styrene polymer particles of the invention may also contain one or more, preferably halogen-free, flame-retardant and / or synergistic compounds. If present, the proportion of such additional flame-retardant compounds is typically 0.5 to 5 parts by weight, based on 100 parts by weight of the styrene polymer.

[0069] The expanded styrene polymer granules (EPS) used according to the invention generally have a bulk density of at most 20 g / L, preferably 5 to 20 g / L, particularly preferably 10 to 15 g / L.

[0070] The present invention also relates to a process for producing a fire-protected insulating material comprising the steps of: mixing an expanded styrene polymer with the aqueous dispersion according to the invention, shaping the resulting mixture, and solidifying the mixture, preferably by drying the mixture.

[0071] The mixing of the styrene polymer material, preferably the expanded polystyrene particles or beads, with the aqueous dispersion of the intumescent adhesive is usually carried out by spraying the aqueous dispersion onto the styrene polymer material using suitable spraying devices, by means of which the aqueous dispersion of the intumescent adhesive is applied in finely distributed form onto the surface of the styrene polymer material.

[0072] An advantage of the claimed stable aqueous dispersions of the present invention is that all components are water-soluble. Therefore, even during prolonged storage and preservation of the aqueous dispersions of the intumescent adhesive, neither sedimentation problems nor the previously known blockages in the lines and spray nozzles of the spray devices used for this purpose occur when mixing or applying the aqueous dispersion to the styrene polymer materials. Furthermore, when mixing or applying the aqueous dispersions according to the invention, it is evident that the previously common dilution and application problems that resulted from the lack of homogeneity of the adhesives previously used no longer occur.A further advantage of the aqueous dispersions according to the invention is the excellent storage stability of the corresponding aqueous formulation, since a relatively low dosage of active components is present in the intumescent adhesive, which nevertheless ensures sufficient consolidation of the insulation material and simultaneously enables excellent fire protection properties for the resulting composites. The problem of sedimentation of the solid components, familiar from conventional intumescent adhesives even after relatively short storage times, can also be avoided for the first time with the help of the aqueous dispersions according to the invention.

[0073] The styrene polymer and the dispersions according to the invention are preferably mixed in a specific mixing ratio. The mixing ratio must be selected to ensure sufficient flowability of the styrene polymer material, thus still allowing easy filling in the subsequent step. Therefore, when determining a suitable mixing ratio of polystyrene to aqueous dispersion, the particle size and bulk density of the styrene polymer material must also be taken into account.

[0074] Preferred mixing ratios of expanded styrene polymer to adhesive material are typically in the range of 0.5 to 10 parts by weight, preferably 1 to 8 parts by weight, particularly preferably 1.5 to 5 parts by weight, and most particularly preferably 2 to 4 parts by weight. These weight ratios and the underlying typical densities of the two components of approximately 12 g / l expanded styrene polymer and 1100 g / l adhesive result in the following preferred mixing volume ratios.

[0075] Preferred volume ratios are in the range of 0.5 to 30 cm 3 , preferably 1 to 20 cm 3 , particularly preferably 2 to 15 cm 3 , and most preferably 3 to 10 cm 3 , of intumescent adhesive per liter of expanded styrene polymer, in particular expanded polystyrene beads. A volume ratio of 4 to 8 cm 3 of intumescent adhesive per liter of expanded styrene polymer, in particular expanded polystyrene beads, is best. In these ratios, the composite materials obtained by mixing and subsequently drying the expanded styrene polymer and the aqueous dispersions according to the invention meet the requirements of fire protection class E according to EN 13501-1.

[0076] The resulting mixture is preferably shaped by filling a cavity with the mixture of the expanded styrene polymer with the aqueous dispersion according to the invention. Suitable filling aids such as spray aids, large syringes, or pouring funnels can be used for filling.

[0077] Drying of the mixture leads to the solidification of the adhesive polymer component in the aqueous dispersion according to the invention. This results in the fixation or bonding of the expanded styrene polymer, in particular the expanded styrene particles or beads, in the filled cavity. Drying can be achieved by simply allowing the resulting composite material of expanded styrene polymer and intumescent adhesive to dry in the filled cavity, i.e., without additional measures, or by supporting measures such as bringing the insulating material into contact with air or heated air, or by applying heat using a suitable device.

[0078] The manufacturing process described above results in a composite material by bonding an expanded styrene polymer with the aqueous dispersion of the invention. This composite material combines the thermal insulation properties of the expanded styrene polymer with the fire-protection properties of both materials, i.e., the expanded styrene polymer and the intumescent adhesive. The composite material of the invention is therefore capable of meeting the product requirements defined in fire behavior class E of the fire protection standard EN 13501-1.

[0079] The present invention also relates to a composite material produced from the aqueous dispersion and an insulating material. In this context, the aqueous dispersion is used as an intumescent adhesive, so that a suitable insulating protection material is bonded to the adhesive. The composite material comprises an expanded styrene polymer and the aqueous dispersion as an intumescent adhesive, obtainable by mixing the expanded styrene polymer, in particular expanded polystyrene beads, with the aqueous dispersion according to the invention, shaping the resulting mixture, and then drying it. The resulting composite material is no longer free-flowing due to the bonding and is therefore preferably formed directly on site by filling the mixture into a suitable cavity of a building before it solidifies.

[0080] The present invention therefore also relates to the use of the aqueous dispersion according to the invention as an intumescent adhesive in the solidification of insulating materials, in particular those formed from expanded styrene polymers. As already described above, the use of the intumescent adhesive involves mixing, in particular applying, the intumescent adhesive as an aqueous dispersion to the expanded styrene polymer, in particular to expanded polystyrene, which is preferably in free-flowing form, i.e. in particular as expanded polystyrene beads, shaping the resulting mixture, preferably either by filling a suitable cavity with the mixture before its solidification or alternatively by other shaping measures in which panels, blocks, bricks or the like of the composite material are obtained, which can then subsequently be stored, transported and installed separately.

[0081] The aqueous dispersions according to the invention are therefore suitable for use as an adhesive component for the production of fire-protected insulating materials, which can be shaped or fixed by adding the additional adhesive component to a suitable insulating material such as, for example, an expanded styrene polymer, so that, in particular, cavities in buildings can be completely filled with a suitable insulating material and protected from subsequent leakage.

[0082] The use according to the invention therefore preferably relates to the use of the aqueous dispersions according to the invention as intumescent adhesives, characterized in that the aqueous dispersion is mixed as a liquid adhesive with an insulating material, shaped and then dried, so that in this way a fire-protected insulating material is obtained.

[0083] The use of the aqueous dispersions according to the invention is therefore particularly suitable for the fixation of fire-protected foam materials such as expanded styrene polymers, in particular expanded polystyrene, since non-free-flowing, fixed and fire-protected insulating materials with high thermal insulation performance can be provided.

[0084] In a preferred embodiment, the use according to the invention therefore also relates to the use of the insulating material for insulating multi-layer masonry, in particular double-layer walls. Examples Example 1: Production of a fire-protected molded body

[0085] 67.5 g of water are placed in a stirred container, and 15 g of monoammonium phosphate are dissolved therein under continuous stirring. 5 g of sucrose are then dissolved in this saline solution, followed by 12.5 g of a 50% vinyl acetate / VeoVa dispersion. Finally, a preservative is dissolved in the intumescent mixture.

[0086] 5 cm3 of this mixture are dropped onto 1000 cm3 of EPS beads with an average outer diameter of 1.5 mm and distributed homogeneously on the surface of the beads in a mixing vessel using a stirring spatula.

[0087] This mixture is poured into a mold and dried at room temperature. This creates a cuboid-shaped, fragile molded body that meets construction product class E according to EN 13501-1. Example 2: Production of a fire-protected plate-shaped body

[0088] 63 g of water are placed in a stirred container, and 16 g of monoammonium phosphate are dissolved therein under continuous stirring. 5 g of sucrose and 1.5 g of urea are then dissolved in this salt solution, followed by the addition of 14.5 g of a 50% vinyl acetate / VeoVa dispersion.

[0089] 6 cm3 of this mixture are sprayed onto 1000 cm3 of EPS beads with an outer diameter of 0.8 - 1.6 mm in a ploughshare mixer while the mixing unit is running.

[0090] This mixture is poured into a mold and dried at room temperature. This creates a panel-shaped body that meets construction product class E according to EN 13501-1.

Claims

1. Aqueous dispersion comprising the following components: - at least one binder in dispersion form - at least one water-soluble salt of phosphoric acid - at least one water-soluble carbohydrate which is a disaccharide - optionally at least one water-soluble ammonium salt and / or at least one amino compound, wherein the at least one binder in dispersion form comprises a stabilized dispersion containing a copolymer of vinyl acetate and a vinyl ester of a further long-chain carboxylic acid.

2. Aqueous dispersion according to Claim 1, wherein the vinyl acetate copolymer is a copolymer which is obtained by copolymerization of vinyl acetate and a vinyl ester of neodecanoic acid.

3. Aqueous dispersion according to any one of the preceding Claims 1 to 2, wherein the at least one binder in dispersion form is present in an amount of 5 to 40 parts by weight, preferably 10 to 20 parts by weight, based on the aqueous dispersion.

4. Aqueous dispersion according to any one of the preceding Claims 1 to 3, wherein the at least one water-soluble salt of phosphoric acid comprises an ammonium salt of phosphoric acid, preferably monoammonium phosphate.

5. Aqueous dispersion according to any one of the preceding Claims 1 to 4, wherein the amount of monoammonium phosphate is 5 to 30 parts by weight, preferably 10 to 20 parts by weight, based on the aqueous dispersion.

6. Aqueous dispersion according to any one of the preceding Claims 1 to 5, wherein the at least one water-soluble carbohydrate which is a disaccharide is present in an amount of 2 to 20 parts by weight, preferably 3 to 10 parts by weight, based on the aqueous dispersion.

7. Aqueous dispersion according to any one of the preceding Claims 1 to 6, wherein the at least one water-soluble carbohydrate which is a disaccharide contains sucrose.

8. Aqueous dispersion according to any one of the preceding Claims 1 to 7, wherein the at least one water-soluble ammonium salt and / or the at least one amino compound is present in an amount of 0 to 10 parts by weight, preferably 1 to 5 parts by weight, based on the aqueous dispersion.

9. Aqueous dispersion according to any one of the preceding Claims 1 to 8, wherein the at least one water-soluble ammonium salt and / or the at least one amino compound contains urea.

10. Method for producing a fireproofed insulating material, comprising the following steps: - mixing an expanded styrene polymer with the aqueous dispersion according to any one of Claims 1 to 9, - shaping the mixture obtained, and - solidifying the mixture, preferably by drying the mixture.

11. Composite material comprising an expanded styrene polymer and an intumescent adhesive, obtainable by mixing the expanded styrene polymer with the aqueous dispersion according to any one of the preceding Claims 1 to 9, shaping the mixture obtained and then drying it.

12. Use of the aqueous dispersion according to any one of the preceding Claims 1 to 9 as an intumescent adhesive, characterized in that the aqueous dispersion is mixed as a liquid adhesive with an insulant material, is shaped and then is dried to give a fireproofed insulating material.

13. Use according to Claim 12, wherein the foam material comprises expanded polystyrene and the insulating material is used for the insulation of double-leaf walling.