Structural element and method for the production thereof

Abstract

The invention relates to a structural element comprising a stone layer which has a stone surface, the stone surface being coated with a reflective coating system, the reflective coating system being substantially concrete-free and being designed such that it can reflect infrared radiation and substantially has the appearance of the stone surface. The invention also relates to a method for producing the structural element and to the use of the structural element.

Description

[0001] Component and method for its manufacture

[0002] The invention relates to a building component comprising a layer of stone with a stone surface, wherein the stone surface is coated with a reflective coating system. The invention also relates to methods for manufacturing the building component according to the invention and to the use of the building component according to the invention.

[0003] Components absorb infrared radiation, for example from sunlight, and heat up through the absorption of this radiation.

[0004] This effect affects both natural stone and artificial stone-based building elements, such as concrete elements. Due to the widespread use of such building elements in building construction and landscape architecture, increasing solar radiation leads to undesirable heating effects. These heating effects can worsen the microclimate, particularly within densely populated areas, especially during the summer months.

[0005] For this reason, there have recently been efforts to use building materials with a high infrared-reflecting content, which heat up significantly less under sunlight than conventional building materials. For example, the US government's LEED (Leadership in Energy and Environmental Design) program explicitly encourages the use of building materials that are energy-efficient, water-saving, and climate-friendly.

[0006] For example, DE 10 2005 061 684 A1 describes the use of infrared-reflecting pigments for paints and cosmetics. In the building materials sector, the use of infrared-reflecting pigments for concrete products is described in the...

[0007] US 2009 027 2297 A1 describes this; however, the infrared reflective pigments used negatively affect the optical appearance of the concrete products. An optically unaffected surface design with high IR reflectivity is not yet known in the prior art.

[0008] The object of the invention is therefore to provide generic components that at least partially overcome the disadvantages of the prior art. In particular, visually appealing components that exhibit lower heating effects are to be provided.

[0009] Further tasks arise from the following explanations and are partially listed below.

[0010] All or some of these problems are solved according to the invention by the component according to claim 1 and the methods according to claims 18, 23, 24 and 25 as well as the use according to claim 26.

[0011] Advantageous embodiments of the invention are specified in the dependent claims and are explained in detail below.

[0012] The invention provides a building element comprising a layer of stone with a stone surface, wherein the stone surface is coated with a reflective coating system, wherein the reflective coating system is essentially concrete-free and is designed to reflect infrared radiation and essentially maintain the optical appearance of the stone surface.

[0013] Surprisingly, it was found that the use of the reflective coating system according to the invention achieved a significant reflection of the infrared radiation striking the component without impairing the appearance of the stone surface. Without being bound to any specific scientific theory, the infrared-reflecting particles in the reflective coating system appear to be invisible to the human eye, yet they effectively modify the optical properties of the component, reflecting infrared radiation, a non-visible component of sunlight, without affecting the overall optical appearance of the component. Thus, the stone surface, and consequently the optical appearance of the component, can still be designed as desired, while thermally favorable reflective properties are also achieved.

[0014] Essentially concrete-free means, in particular, that the coating system is not concrete-based. The coating system contains concrete, especially only in trace amounts. The coating system does not include a concrete layer. The coating system is preferably concrete-free.

[0015] According to a preferred embodiment, the stone layer comprises or consists of artificial stone, wherein the artificial stone includes a binder. Artificial stones are frequently used due to their durability and lower price compared to natural stone stones, slabs, or steps. Artificial stones are preferably concrete elements such as concrete blocks, concrete slabs, concrete wall elements, facing blocks, or concrete steps. Various methods have been developed to give the artificial stones a decorative appearance. These methods typically involve adding pigment and / or natural stone aggregates and / or sands to color and enhance the artificial stone element. The artificial stone can be a single piece or, for example, have a core layer and a facing layer.

[0016] The binder can be a mineral binder. The mineral binder can be water-activated. The mineral binder can be alkaline-curing agents. The mineral binder can be heat-activated. Examples of important mineral binders are inorganic binders such as cement, lime, and gypsum. Such binders are particularly easy to handle, especially in connection with concrete elements. Furthermore, they do not place any additional demands on the manufacturing process. Other examples of mineral binders are latent hydraulic binders, pozzolanic binders, and metakaolin.

[0017] According to a preferred embodiment, the binder is cement. Cement is a hydraulic binder that, when mixed with water, forms cement paste. After setting and hardening through hydration, cement remains solid and dimensionally stable even underwater.

[0018] According to another preferred embodiment, the binder is a latent hydraulic binder and / or a pozzolanic binder.

[0019] Preferably, the artificial stone, particularly according to this embodiment, contains 5% by weight or less, preferably 3% by weight or less, cement. More preferably, the artificial stone is essentially cement-free. Cement-containing artificial stones sometimes exhibit the problem of developing whitish spots, known as efflorescence, on their surface over time. Furthermore, colored artificial stones can fade. Both effects appear to be caused by the formation of lime. The whitish spots on the surface are attributed to efflorescence, which forms from the reaction of calcium hydroxide transported to the surface with carbon dioxide. It is assumed that the color fading occurs, among other things, because the pigment, which has deposited on the cement particles to provide color, is slowly coated by the calcium carbonate that forms. In this way, the color impression of the pigment is gradually lost.

[0020] Alternative binders to cement, such as latent hydraulic binders and / or pozzolanic binders, are known to those skilled in the art. Advantageously, such alternative binders are based on the chemical building blocks SiO₂ in combination with Al₂O₃. The aforementioned latent hydraulic and pozzolanic binders are preferably also referred to as "geopolymers" or "alkaline-activated materials." For example, EP 1 236 702 A1 describes a building material mixture containing water glass and a latent hydraulic binder. EP 1 236 702 A1 proposes using the building material mixture as mortar or filler.

[0021] Various substances are suitable as latent hydraulic binders.

[0022] Preferably, the molar ratio of (CaO + MgO) to SiO₂ in the latent hydraulic binder is between 0.8 and 2.5, more preferably between 1.0 and 2.0. Latent hydraulic binders with a molar ratio of (CaO + MgO) to SiO₂ in the aforementioned range cure well. Advantageously, the latent hydraulic binder is selected from the group consisting of slag, blast furnace slag, preferably granulated blast furnace slag, in particular ground granulated blast furnace slag, electrothermal phosphorus slag, steel slag, and mixtures thereof. Granulated blast furnace slag, in particular ground granulated blast furnace slag, is further preferred. Most preferably, the molar ratio of (CaO + MgO) to SiO₂ in the latent hydraulic binder is between 0.8 and 2.5, and the latent hydraulic binder is selected from the aforementioned materials.

[0023] Various substances are suitable as pozzolanic binders.

[0024] Preferably, the pozzolanic binder is selected from the group consisting of amorphous silicon dioxide, precipitated silicon dioxide, pyrogenic silicon dioxide, microsilica, glass flour, fly ash such as lignite fly ash or bituminous coal fly ash, metakaolin, natural pozzolans such as tuff, trass or volcanic ash, natural and synthetic zeolites and mixtures thereof. Amorphous silicon dioxide is particularly preferred as the pozzolanic binder.

[0025] Artificial stones can be produced using the aforementioned latent hydraulic and pozzolanic binders, whose decorative properties do not fade or fade only very slowly, especially if they contain little or no cement. Furthermore, artificial stones containing 5 wt.% or less, preferably 3 wt.% or less, cement, or even essentially cement-free, have an improved CO₂ balance compared to cement-bound artificial stones.

[0026] The binder can be an alkaline-activated binder. Such binders are treated with an alkaline compound to activate them. The alkaline compound can also be called an alkaline curing agent. Various substances are suitable as the alkaline compound. Preferably, the alkaline compound is selected from the group consisting of alkali metal oxides, alkali metal hydroxides, alkali metal carbonates, alkali metal silicates, alkali metal aluminates, and mixtures thereof, more preferably consisting of alkali metal hydroxides, alkali metal silicates, and mixtures thereof. Examples of alkali metal oxides are Li₂O, Na₂O, K₂O, (NH₄)₂O, and mixtures thereof. Examples of alkali metal hydroxides are LiOH, NaOH, KOH, NH₄OH, and mixtures thereof.

[0027] Examples of alkali metal carbonates are Li₂CO₃, Na₂CO₃, K₂CO₃, (NH₄)₂CO₃, and mixtures thereof. Due to its similarity to the alkali metal ions, the ammonium ion is also listed. Advantageously, alkali metal silicates are selected from compounds with the empirical formula mSiO₂ · nM₂O, where M is Li, Na, K, or NH₄, or a mixture thereof, preferably Na or K. The molar ratio of mm is from 0.5 to 3.6, preferably from 0.6 to 3.0, and particularly preferably from 0.7 to 2.0. Water glass, especially liquid water glass, and more preferably liquid sodium and / or potassium water glass, has proven to be a particularly suitable alkali metal silicate. Silica, especially aqueous silica, is another suitable alkali metal silicate. Silica can occur, in particular, as silica sol in alkaline form.

[0028] According to another embodiment, the binder is a resin, in particular a synthetic resin. Synthetic resins are produced synthetically by polymerization, polyaddition, or polycondensation. Synthetic resins include a wide variety of compounds, such as acrylic and epoxy resins, silicones, and polyester resins, preferably acrylates and epoxy resins. These binders usually consist of a resin component and a hardener. The artificial stone is preferably produced by combining ground rock flour and synthetic resin. Examples of artificial stones comprising synthetic resins are known as "agglomerated marble" or "quartz composite." Preferably, artificial stones with a resin as a binder contain 1 to 10 wt.%, more preferably 3 to 8 wt.%, of the resin, based on the total weight of the artificial stone.

[0029] According to another embodiment, the artificial stone is ceramic.

[0030] According to a further preferred embodiment, the stone layer comprises or consists of natural stone. In this embodiment, the stone layer preferably comprises less than 1% by weight, more preferably less than 0.5% by weight, and more preferably less than 0.1% by weight, of binder, based on the total weight of the stone layer. Particularly preferably, the stone layer in this embodiment is free of binder. Natural stone generally refers to all rocks as they are found in nature. An advantage of natural stone over other materials is that its extraction and processing require comparatively less energy. Furthermore, natural stone contains fewer pollutants and is therefore less problematic with regard to its disposal.

[0031] Preferably, the reflective coating system comprises one, two, or more layers. The layers can all be the same. The layers can all be different from each other. Some of the layers can be the same and others different. It is possible to incorporate different particles into different layers.

[0032] Advantageously, the reflective coating system comprises two layers with a difference in refractive index, wherein the difference in refractive index is 0.5 or more, preferably 1.0 or more. Preferably, the difference in refractive index is 4.0 or less, more preferably 3.0 or less, and even more preferably 2.0 or less. At the interface between two media with different refractive indices, radiation is refracted and reflected. The refractive index therefore has a significant influence on the reflection and reflection.

[0033] Transmission behavior of materials.

[0034] According to a preferred embodiment, the reflective coating system comprises two layers with a difference in infrared reflectivity, and / or the coating system comprises a metal layer and a protective layer, wherein the metal layer preferably has a thickness of 250 nm to 4000 nm, more preferably 400 nm to 2500 nm. By using two layers with a difference in infrared reflectivity, reflection over a broader wavelength range can be achieved, for example. Metal layers, especially smooth metal layers, exhibit a high reflectivity in the infrared range of up to over 90%. The reflectivity of any object can therefore be improved by coating it with a thin metal layer. A protective layer serves to protect the metal layer from mechanical stress, such as scratching.By combining a metal layer and a protective layer with another layer that has a difference in infrared reflectivity, the reflection of infrared radiation can be improved even further.

[0035] The coating system can comprise or consist of a particle layer containing a binder, particularly an organic binder, and infrared-reflecting particles. Examples of organic binders include, in particular, organic polymers such as silicones, poly(meth)acrylates, polyethylene, and polypropylene.

[0036] According to one embodiment, the reflective coating system comprises or consists of a particle layer which

[0037] A binder comprising a silicone resin and / or a poly(meth)acrylate and infrared-reflecting particles. Such a particle layer is able to reflect infrared radiation and, moreover, exhibits good stability and scratch resistance due to the binder.

[0038] Preferably, the particle layer contains 1 to 60 wt.%, more preferably 1 to 50 wt.%, further preferably 1 to 30 wt.%, even more preferably 1 to 10 wt.%, particularly preferably 2 to 10 wt.%, or preferably 2 wt.% to 60 wt.%, more preferably 5 wt.% to 50 wt.%, more preferably 5 wt.% to 30 wt.%, particularly preferably 5 to 10 wt.% of infrared radiation-reflecting particles, based on the total weight of the particle layer, and / or 35 wt.% to 98 wt.%, more preferably 35 wt.% to 95 wt.%, more preferably 35 wt.% to 90 wt.%, particularly preferably 40 wt.% to 90 wt.%, of binder, based on the total weight of the particle layer. Such a composition allows a particle layer to be obtained that contains both a sufficient number of particles to achieve good reflection of infrared radiation and a sufficient number of binders to achieve good layer stability.A higher particle content could negatively affect the other optical properties of the component.

[0039] The infrared radiation-reflecting particles can be selected from the group consisting of aluminum oxide, titanium dioxide, zirconium dioxide, cerium oxide, zinc oxide, indium tin oxide, mica, and metal particles, wherein the metal is preferably selected from the group consisting of aluminum, copper, zinc, iron, silver, and alloys thereof, and mixtures thereof. Preferably, the infrared radiation-reflecting particles are selected from the group consisting of titanium dioxide, zirconium dioxide, cerium oxide, zinc oxide, indium tin oxide, mica, and metal particles, wherein the metal is preferably selected from the group consisting of aluminum, copper, zinc, iron, silver, and alloys thereof, and mixtures thereof.The infrared radiation-reflecting particles are preferably selected from the group consisting of zirconium dioxide, cerium oxide, zinc oxide, indium tin oxide, metal particles, and mixtures thereof. They are further preferably selected from the group consisting of zinc oxide, indium tin oxide, and metal particles and mixtures thereof, wherein the metal is preferably selected from the group consisting of aluminum, copper, zinc, iron, silver, and alloys thereof. Indium tin oxide particles are particularly preferred. Indium tin oxide is preferably also abbreviated as ITO. The aforementioned materials enable high reflectivity of the reflective coating system in the infrared spectrum and can achieve improved thermal reflectivity of the component even in small weight fractions.

[0040] According to another embodiment, the infrared radiation-reflecting particles are aluminum oxide and / or titanium dioxide. Titanium dioxide can be present as rutile and / or anatase, preferably as rutile.

[0041] Infrared radiation-reflecting particles can have various sizes. The size can be selected based on the desired radiation reflection and optical properties. For example, infrared radiation-reflecting particles can have a size of 1 pm to 100 pm, preferably 1 pm to 50 pm, more preferably 1 pm to 10 pm, and particularly 2 pm to 5 pm. In particular, metal oxide particles and / or metal particles, such as metal platelets, preferably indium tin oxide particles and / or aluminum oxide particles, can have such a size. Infrared radiation-reflecting particles can also be very small. For example, infrared radiation-reflecting particles can have a size of 150 nm or less, preferably 100 nm or less, and more preferably 50 nm or less. Preferably, the particles have a size of 10 nm or more. Titanium dioxide particles can also have such a size.The infrared-reflecting particles can also be larger. For example, the particles can have a size of 50 pm or more, particularly 100 pm or more, especially if the optical properties of the particles do not alter the optical properties of the stone surface. For example, mica particles with a size in the micrometer to millimeter range, for example 300 pm to 1500 pm, can be used as infrared-reflecting particles for a stone surface made of natural stone, an artificial stone surface, or an artificial stone surface that imitates natural stone. The particle size preferably refers to the d50 value. The d50 value can be determined, for example, by laser diffraction, particularly using a Malvern Mastersizer 3000+ Ultra.

[0042] According to one embodiment, the infrared radiation-reflecting particles are plate-shaped. The size of the plate-shaped particles preferably also relates to the d50 value and can be determined by laser diffraction, in particular using a Malvern Mastersizer 3000+ Ultra.

[0043] Advantageously, a primer layer is arranged between the stone surface and the reflective coating system. According to a preferred embodiment, the primer layer is applied particularly on the wet side.

[0044] Applied wet-side means that the primer layer is applied to fresh concrete before the stone layer has hardened. According to another preferred embodiment, the primer layer is applied dry-side. Applied dry-side means that the primer layer is applied to hardened concrete. Particularly on alkaline stone surfaces, such as cement-bound concrete, a primer layer serves to prevent direct contact between the stone surface and the reflective coating system. This allows for greater flexibility regarding the reflective coating system used. Furthermore, it enables better adhesion of the coating system to the stone surface.

[0045] Various layers are suitable as primers. Advantageously, the primer layer improves the adhesion of the coating system to the stone surface. The primer layer is preferably organic or inorganic, particularly acrylate-based or silicone resin-based. Such primers are especially easy to apply and ensure good isolation and / or adhesion of the reflective coating system to the stone surface.

[0046] According to a preferred embodiment, the building element is a stone, in particular a paving stone, a wall element, a facing stone, a step, a roof tile, a facade element, or a slab. The building element can have a single-layer or multi-layer structure, in particular a two-layer structure in the form of a core layer and a facing layer.

[0047] The invention also provides a method for manufacturing components according to the invention, comprising the steps:

[0048] a. Providing a building element comprising a layer of stone with a stone surface,

[0049] b. optional pretreatment of the stone surface with an acidifying agent and / or with a primer and / or with a curling brush to obtain a pretreated stone surface,

[0050] cl. Application of a UV-curable coating material comprising non-functionalized silanes and / or hydrolysates of non-functionalized silanes and / or silicone resins and / or silicones with residues of hydrolyzable alkoxy groups as well as infrared radiation reflecting particles and at least one cationic or anionic UV starter to the stone surface or optionally the pre-treated stone surface,

[0051] dl. Hardening of the coating material, especially by UV radiation, at a radiation energy of 200 to 2500 mJ / cm² 2 preferably from 500 to 2200 mJ / cm² 2 , preferably from 700 to 2000 mJ / cm² 2 , in particular for a duration of 0.1 to 10 s, preferably of 0.5 to 5 s.

[0052] As an alternative to steps cl and dl in the above-described process, the process can also include, in addition to steps a. and optionally b., step c2. Applying a first thin layer, in particular a thin metal layer, to the stone surface, preferably by vapor deposition or sputtering,

[0053] d2. optionally, applying to the first thin layer a second thin layer with a difference in refractive index to the first thin layer, wherein the difference in refractive index is 0.5 or more, preferably 1.0 or more, or a second thin layer with a difference in infrared reflectance.

[0054] Pretreatment with a curling brush, also known as curling, refers specifically to brushing with diamond-tipped brushes. This process removes parts of the surface and, if present, the primer. Curling is essentially the roughening of the surface to improve coating adhesion. Curling can be performed as an alternative or supplement to pretreatment with an acidifying agent. Curling can be performed as an alternative or supplement to pretreatment with a primer. Curling can be performed in addition to pretreatment with an acidifying agent and a primer.

[0055] The metal layer that is applied is, for example, an aluminum layer.

[0056] This process allows for the application of a silicone layer containing infrared-reflecting particles to the stone surface, or the application of multiple layers with different refractive indices, or the application of a thin metal layer with another layer, such as a protective layer, to the stone surface, or the application of multiple layers with differing infrared reflectances. Depending on the coating system, further layers can also be applied. Applying a silane- and / or silicone- and / or silicone resin-based layer containing infrared-reflecting particles offers several advantages.In addition to reflecting infrared radiation to reduce the heating of the component, the stone surface is less susceptible to soiling and easier to clean after applying the silane-based reflective coating system. Surprisingly, it has been shown that non-functionalized silanes and / or hydrolysates of non-functionalized silanes and / or silicone resins and / or silicones with residual hydrolyzable alkoxy groups can be cured significantly faster at room temperature by adding cationic or anionic UV initiators using UV radiation than was possible with conventional systems. Conventional systems typically require curing times of several hours to several days.

[0057] Preferably, the non-functionalized silanes are selected from the group consisting of 2-, 3- or 4-fold alkoxysilanes without an organic functional group, in particular methyltriethoxysilane (MTES), tetraethoxysilane (TEOS), phenyltriethoxysilane (PHTES), propyltriethoxysilane (PTES), dimethyldiethoxysilane (DMDES), methyltrimethoxysilane (MTMS), tetramethoxysilane (TEMOS), tetra-n-propoxysilane, tetra-n-butoxysilane, phenyltrimethoxysilane (PHTMS), propyltrimethoxysilane (PTMS), dimethyldimethoxysilane (DMDMS), isobutyltriethoxysilane, isobutyltrimethoxysilane, octyltriethoxysilane, octyltrimethoxysilane, iso-octyltriethoxysilane, iso-octyltrimethoxysilane, isooctyltriethoxysilane, isooctyltrimethoxysilane, hexadecyltrimethoxysilane. Hexadecyltriethoxysilane, 1,2-bis(triethoxysilyl)ethane, 1,2-bis(trimethoxysilyl)ethane, trimethylethoxysilane, trimethylmethoxysilane, (cyclohexyl)methyldiethoxysilane, cyclohexyl)methyldimethoxysilane, dicyclopentyldiethoxysilane, dicyclopentyldimethoxysilane,Cyclohexyltrimethoxysilane, cyclopentyltrimethoxysilane, ethyltrimethoxysilane, phenylethyltrimethoxysilane, phenyltrimethoxysilane, n-propyltrimethoxysilane, dimethyldimethoxysilane, diisopropyldimethoxysilane, phenylethyldimethoxysilane, phenylethyltriethoxysilane, phenylmethyldiethoxysilane, and phenyldimethylethoxysilane. The use of these silanes allows for good and rapid curing of the coating material. Hydrolysates of the aforementioned silanes are known to those skilled in the art.

[0058] According to a preferred embodiment, the UV starter is a cationic UV starter selected from the group consisting of (4-methylphenyl)[4-(2-methylpropyl)phenyl]iodonium hexafluorophosphate, triarylsulfonium hexafluorophosphate, bis[4-diphenylsulfoniumphenyl]sulfide bishexafluoroantimonate, thiophenoxyphenylsulfonium hexafluoroantimonate, thiobis(4,1-phenylene)-S, S, S', S'-tetraphenyldisulfonium bishexafluorophosphate, diphenyl(4-phenylthiophenylsulfonium hexafluorophosphate), (4-{[4-(diphenylsulfanylium)phenyl]sulfanyl}phenyl)diphenylsulfonium bishexafluorophosphate, (thiodi-4,1-phenylene)-bis-(diphenylbis)(OC-6,11)hexafluoroantimonate, diphenyl[4-(phenylthio)phenyl]sulfonium hexafluoroantimonate, bis-(4-dodecylphenyl)iodonium hexafluroantimonate, thiobis(4,l-phenylene)-S, S, S', S'-tetraphenyldisulfonium bishexafluorophosphate;diphenyl(4-phenylthiophenyl)sulfonium hexafluorophosphate, phenyl-p-octyloxyphenyliodonium hexafluoroantimonate, bis(dodecylphenyl)odonium hexafluoroantimonate, bis-(4-methylphenyl)iodonium hexafluorophosphate, diphenyl(4-phenyl-thio)phenylsulfonium hexafluoroantimonate, and (thio-4,1-phenyene)bis(diphenylsulfonium)dihexafluoroantimonate). The use of these cationic UV starters allows for good and rapid curing of the coating material.

[0059] According to another preferred embodiment, the UV starter is an anionic UV starter selected from the group consisting of aryldiazonium compounds or ketoprofen-type compounds, such as 1,3-di-4-piperidylpropanedi(α-(2-benzoyl)phenylpropionate), 1,6-hexamethylenediaminedi(α-(2-benzoyl)phenylpropionate), and 9-DBU(2-benzoyl)phenylpropionate. The use of these anionic UV starters allows for good and rapid curing of the coating material. Anionic UV starters are particularly well-suited for alkaline substrates.

[0060] The UV-curable coating material can in particular have a solids content of 60% or higher, preferably 70 to 100%, preferably 80 to 100%.

[0061] Examples of silicone resins include methyl silicone resins, phenyl silicone resins, and mixtures thereof.

[0062] As an alternative to steps cl and dl or c2 and d2 in the procedure described herein, the procedure may also include the following steps in addition to steps a. and optionally b.:

[0063] c3. Applying, preferably by spraying, a coating material in the form of an aqueous emulsion comprising at least one acrylic polymer and infrared-reflecting particles to the stone surface or, optionally, the pretreated stone surface; d3. Curing the coating material at a surface temperature of 15°C to 80°C, preferably 30°C to 70°C, more preferably 45°C to 65°C, in particular by IR radiation, especially for a duration of 10 seconds to 10 minutes, preferably 10 seconds to 30 seconds, and / or by UV radiation with 500 to 2500 mJ / cm² 2 .

[0064] As a further alternative to steps cl and dl or c2 and d2 or c3 and d3 in the procedure described herein, the procedure may also include the following steps in addition to steps a. and optionally b.:

[0065] c4. Providing a coating material comprising at least one acrylic polymer and IR-reflecting particles, preferably with a viscosity of 50 to 300 mPas, more preferably 100 to 250 mPas, more preferably 100 to 200 mPas, d4. Applying the coating material to the surface by rolling,

[0066] e4. Curing of the coating material at a surface temperature of 130°C to 220°C, in particular by IR radiation, especially for a duration of 10 seconds to 10 minutes, preferably 10 seconds to 30 seconds, and / or by UV radiation with 500 to 2500 mJ / cm² 2 .

[0067] Suitable acrylic polymers include, in particular, polymers and copolymers based on acrylic acid, methacrylic acid and their derivatives, preferably their esters.

[0068] The above-mentioned procedure steps are preferably carried out in the specified order.

[0069] This type of so-called dry-face coating has the advantage of being easier, more precise, and more controlled to apply. Furthermore, it allows for a pre-selection of the finished stones. Additionally, the coating system can be better adapted to the finished stone surface, for example, in terms of its visual appearance.

[0070] The invention provides a further manufacturing process, particularly for building components comprising artificial stone. Specifically, the artificial stone layer can be obtained by curing an artificial stone mixture comprising the binder described herein and granular material, in particular aggregate such as sand, gravel, and / or crushed stone. This further manufacturing process for building components according to the invention comprises the following steps:

[0071] A. Providing an artificial stone mixture in a mold, wherein the artificial stone mixture has a mixing surface, B. optionally pretreating the mixing surface with a primer to obtain a pretreated mixing surface, C1. Applying, in particular spraying, a UV-curable coating material comprising non-functionalized silanes and / or hydrolysates of non-functionalized silanes and / or silicone resins and / or silicones with residues of hydrolyzable alkoxy groups as well as infrared-reflecting particles and at least one cationic or anionic UV starter to the mixing surface or optionally the pretreated mixing surface,

[0072] D1. Curing of the artificial stone mixture,

[0073] E1. Hardening of the coating material, especially by UV radiation, at a radiation energy of 200 to 2500 mJ / cm² 2 preferably from 500 to 2200 mJ / cm² 2, preferably from 700 to 2000 mJ / cm² 2 , in particular for a duration of 0.1 to 10 s, preferably of 0.5 to 5 s.

[0074] As an alternative to steps CI, Dl and El in the procedure described above, the procedure can also include steps A and optionally B.

[0075] C2. Application, preferably by spraying, of a coating material in the form of an aqueous emulsion comprising at least one acrylic polymer and infrared-reflecting particles onto the stone surface or optionally the pretreated stone surface, D2. Curing of the artificial stone mixture,

[0076] E2. Curing of the coating material at a surface temperature of 15°C to 80°C, preferably 30°C to 70°C, more preferably at 45°C to 65°C, in particular by IR radiation, especially for a duration of 10 seconds to 10 minutes, preferably 10 seconds to 30 seconds, and / or by UV radiation with 500 to 2500 mJ / cm²2 include.

[0077] Suitable acrylic polymers include the polymers mentioned above. The process steps described above are preferably carried out in the specified order.

[0078] This type of so-called wet-side coating has the advantage of filling or lining the existing pore volume of the concrete to prevent the transport of substances, particularly calcium hydroxide. This prevents the accumulation of calcium hydroxide and, through CO2 exposure, calcium carbonate in the pores of the concrete, which can lead to white discoloration. Furthermore, the coating system is better bonded and anchored to the concrete. The curing time of the concrete can also be used to harden the coating. The wet-side coating is particularly preferably applied with an emulsion of an acrylic polymer, steps C2 to E2.

[0079] The above statements regarding the component according to the invention apply accordingly to the aforementioned methods for manufacturing the component, particularly with regard to the quantities of components used.

[0080] The present invention also relates to the use of the building element according to the invention as a floor covering for residential environment design.

[0081] The above statements regarding the component according to the invention apply accordingly to the aforementioned use of the component.

[0082] In addition to or alongside the provision of building components with reduced heating effects through an infrared radiation-reflecting coating, it has been found that reduced heating effects can also be achieved through specially structured concrete layers. Accordingly, the invention relates, according to a further aspect, to a concrete element comprising a concrete layer, in particular a facing concrete layer, characterized in that the concrete layer, in particular the facing concrete layer, contains microhollow spheres. Due to the presence of the microhollow spheres in the concrete layer, the concrete layer exhibits a high pore volume. This high pore volume reduces the thermal conductivity of the concrete layer. As a result, the concrete layer containing the microhollow spheres conducts absorbed heat to a lesser extent into deeper layers and, in particular, exhibits an insulating effect.

[0083] Surprisingly, the concrete layer containing microhollow spheres retains excellent mechanical properties. Therefore, the concrete layer can still function as a facing layer, such as a paving stone facing. To achieve an insulating effect, it is not necessary for the concrete layer to have increased porosity, as is the case with open-pore concrete. Using open-pore facing concrete with comparable insulating properties would, due to the open pores, lead to reduced stability and higher water absorption of the concrete element, which could, for example, decrease its resistance to freeze-thaw cycles and de-icing salts.

[0084] According to one embodiment, the concrete layer, in particular the facing concrete layer, contains microhollow spheres in a quantity of 1 to 100 kg / m². 3 , preferably 1 to 50 kg / m² 3 , preferably 5 to 50 kg / m² 3, especially preferably 5 to 30 kg / m² 3 , relative to the total volume of the facing concrete layer.

[0085] According to another embodiment, the concrete layer, in particular the facing concrete layer, contains microhollow spheres with a pore volume of 1 to 3001 / m³. 3 , further preferred, 1 to 1501 / m² 3 , especially preferably 10 to 1001 / m 3 , most preferred 15 to 751 / m 3 based on the total volume of the facing concrete layer.

[0086] According to a further embodiment, the concrete layer is a facing concrete layer, and the concrete element additionally comprises a core concrete layer. Preferably, the core concrete layer is located below the facing concrete layer.

[0087] arranged. According to a further embodiment, the facing concrete layer and / or the core concrete layer comprises a binder, for which what was previously said for the binder of the stone layer applies.

[0088] The concrete layer may also contain aggregates. Examples of aggregates are gravel, crushed stone, sand, perlite, diatomaceous earth, and / or vermiculite.

[0089] Additives may also have been used in the production of the concrete layer, for example plasticizers, antifoaming agents, water retention agents, dispersants, pigments, fibers, redispersible powders, wetting agents, impregnating agents, complexing agents, rheology additives and / or setting retarders.

[0090] The concrete layer preferably comprises the binder in an amount of 5 to 45 wt.%, preferably 10 to 40 wt.%, further preferably 10 to 30 wt.%, particularly preferably 15 to 30 wt.%, based on the mass of binder and aggregates.

[0091] The concrete layer of the building element according to the invention can be uncoated or coated. For example, the concrete layer can be impregnated. Furthermore, the concrete layer can be coated with the reflective coating system according to the invention. Another object of the invention is therefore a building element according to the invention, wherein the stone layer comprises or consists of a concrete element according to the invention. In this case, the stone layer comprises or consists of artificial stone. Preferably, in this case, the concrete layer of the building element is a facing concrete layer, which is further preferably the stone layer of the building element.

[0092] Without being bound to a scientific theory, such a building element can counteract heating effects particularly effectively. The coating system according to the invention can reflect incoming IR radiation, while the concrete layer prevents heat conduction into deeper layers and thus their heating.

[0093] According to a further embodiment, the core concrete layer has one or more of the following properties. Preferably, the core concrete layer contains cement as a binder. In addition to the cement, the core concrete layer may contain latent hydraulic and / or pozzolanic fillers, in particular fly ash, blast furnace slag, slag, amorphous silicon dioxide, precipitated silicon dioxide, tuff, trass, volcanic ash, zeolites, or mixtures thereof, as a binder additive. If cement or a mixture of cement with latent hydraulic and / or pozzolanic fillers is used as the binder, the core concrete layer expediently contains 5 to 30 wt.%, preferably 5 to 25 wt.%, more preferably 5 to 20 wt.%, and particularly preferably 7 to 18 wt.%, binder, based on the total weight of the core concrete layer. The binder preferably contains at least 35 wt.% cement, more preferably at least 40 wt.% cement, and particularly preferably at least 60 wt.% cement.-%, most preferably at least 80 wt.%, based on the total weight of the binder. According to this embodiment, the core concrete layer can also contain an alkali-activated binder, preferably in an amount of 5 to 45 wt.%, more preferably 10 to 40 wt.%, further preferably 10 to 30 wt.%, and particularly preferably 15 to 30 wt.%, based on the mass of binder and aggregates. The above applies to the alkali-activated binder. The alkaline hardening agent is preferably used for the alkali-activated binder in an amount of 3 to 10 wt.%, more preferably 3 to 9 wt.%, based on the total weight of binder. Furthermore, according to this embodiment, the core concrete layer can contain admixtures for controlling the rheology, setting, hardening, and / or for hydrophobing the concrete, preferably in an amount of 0.5 to 5 wt.%, based on the total weight of the core concrete layer.According to this embodiment, the core concrete layer can also contain up to 7.5 wt.% pigment, for example, metal oxide pigments such as iron oxide or titanium dioxide. Furthermore, according to this embodiment, the core concrete layer preferably contains aggregates, particularly in an amount of 50 to 90 wt.%, more preferably 55 to 90 wt.%, based on the total weight of the core concrete layer. The aggregate preferably has a grading curve coarser than C8 according to DIN 1045. Alternatively, the aggregate can have a particle size distribution such that, in a sieve test, 10 to 45 wt.% remain on the 1.0 mm sieve, 3 to 10 wt.% remain on the 500 pm sieve, and 3 to 5 wt.% remain on the 125 g / m sieve, based on the total weight of the aggregate. Alternatively or additionally, the core concrete layer can contain microhollow spheres in an amount of 1 to 100 kg / m³. 3 , preferably 1 to 50 kg / m² 3 , preferably 5 to 50 kg / m² 3, especially preferably 5 to 30 kg / m² 3 , relative to the total volume of the core concrete layer, or microhollow spheres with a pore volume of 1 to 3001 / m³ 3 , further preferred, 1 to 150 1 / m 3 , especially preferably 10 to 1001 / m 3 , most preferred 15 to 751 / m 3 based on the total volume of the core concrete layer. For the production of the core concrete layer, water is expediently used in an amount of 3 to 8 wt.%, preferably 4 to 7 wt.%, based on the total weight of binder, pigment and aggregates.

[0094] For further clarification, non-limiting examples are listed below.

[0095] EXAMPLES

[0096] materials

[0097] Cement, sand, gravel, crushed stone, colored natural stone chippings, water, iron oxide color pigments

[0098] methods

[0099] Production of the core concrete mix

[0100] The materials cement, sand, gravel, and crushed stone are fed into a mixer and mixed. Adding water creates an earth-moist concrete mix, which is used as core concrete. Production of the facing concrete mix.

[0101] Simultaneously, the materials cement, sand, gravel and crushed stone, colored natural stone chippings and color pigments are fed into a mixer and mixed. By adding water, an earth-moist concrete mix is ​​obtained, which is used as facing concrete.

[0102] Production of two-layer concrete elements

[0103] The prepared core concrete and facing concrete mixes are fed into stone-forming machines, which first fill the molds with the core concrete in layers, compact it by vibration, and then pour the facing concrete onto the compacted core concrete layer. Finally, the concrete is compacted into the concrete elements using vibration.

[0104] The compacted concrete elements are demolded immediately after compaction and placed on supports in the curing chamber. An acrylate-based primer can be applied after demolding, for example, during the transport process.

[0105] Post-processing of the concrete element

[0106] After curing (15 - 48 h), surface treatment can be carried out as required by bush hammering, blasting or grinding.

[0107] Coating of the surface of the concrete element

[0108] For the subsequent coating process, the surface of the concrete element is preheated using IR radiation, or conditioned to a surface temperature of 45 - 65°C and dried.

[0109] A coating agent is rolled onto the preheated surface.

[0110] After application, intermediate thermal curing and UV curing can take place. The concrete elements are then packaged.

[0111] Example 1: Core concrete mix: 320 kg cement, 950 kg sand, 945 kg gravel and 135 liters water. Facing concrete mix: 400 kg cement, 1050 kg sand, 750 kg colored natural stone chippings, 150 liters water.

[0112] According to the above regulation for the production of two-layer concrete elements, a two-layer concrete element with a density of 2.35 kg / dm³ was produced. 3 produced, with a facing concrete density of 2.31 kg / dm³ 3 fraud.

[0113] The concrete element was then cured in a curing chamber at 25°C and 90% RH for a period of 24 hours.

[0114] The concrete element surface was then reworked by curling (diamond-coated brushes) of hardness 120, at 600 rpm and 14 amp drive energy / l.2m feed rate.

[0115] For coating, the surface of the received concrete element was subsequently preheated to 55°C according to the above procedure. 100 g of a silane-based coating material comprising 10 wt% indium tin oxide particles (ITO particles) with a size (d50) of 3 to 4 pm, based on the total weight of the coating material, were applied to the preheated surface as a coating system by roller application.

[0116] The coated concrete element was heated to 80°C for 5-20 seconds and then subjected to UV irradiation at 2000 mj / cm². 2 hardened.

[0117] Example 2

[0118] Core concrete mix: 310 kg blast furnace slag, 90 kg fly ash, 62 kg activator solution (62% solids content), 870 kg sand, 1015 kg gravel, and 105 liters of water. Facing concrete mix: 505 kg alkali-activated binder, 94 kg activator solution (50% solids content), 1005 kg sand, 603 kg colored natural stone chippings, 19.5 kg color pigment, and 105 liters of water.

[0119] According to the above regulation for the production of two-layer concrete elements, a two-layer concrete element with a density of 2.33 kg / dm³ was produced. 3 produced, with a facing concrete density of 2.32 kg / dm³ 3 The concrete element was then cured in a hardening chamber at 30°C and 90% RH for a period of 24 hours.

[0120] The concrete element surface was then reworked by scraping with a diamond tool and curling (diamond-tipped brushes) of hardness 120, at 600 rpm and a feed rate of 14 amps / l.2m. For coating, the surface of the resulting concrete element was then preheated to 55°C according to the above procedure. 100 g of a silane-based coating compound containing 10 wt% indium tin oxide particles (ITO particles) with a size (d50) of 3 to 4 pm, based on the total weight of the coating compound, was applied to the preheated surface by roller application.

[0121] The coated concrete element was heated to 80°C for 5-20 seconds and then irradiated with UV radiation at 2000 mj / cm². 2 hardened.

[0122] Example 3

[0123] Core concrete mix: 320 kg cement, 950 kg sand, 945 kg gravel and 135 liters water. Facing concrete mix: 400 kg cement, 1050 kg sand, 750 kg colored natural stone chippings, 150 liters water.

[0124] According to the above regulation for the production of two-layer concrete elements, a two-layer concrete element with a density of 2.35 kg / dm³ was produced. 3 produced, with a facing concrete density of 2.31 kg / dm³ 3 amounts.

[0125] After demolding and before placement in the curing chamber, an aqueous acrylate system (45% solids) was sprayed onto the surface of the concrete element. The concrete element was then cured in a curing chamber at 25°C and 70% relative humidity for 24 hours.

[0126] The concrete element surface was then post-processed by curling (diamond-tipped brushes) with a hardness of 120 at 600 rpm and a drive energy of 14 amps / l.2m feed rate. For coating, the surface of the resulting concrete element was then preheated to 55°C according to the above procedure. 100 g of a silane-based coating compound containing 10 wt% indium tin oxide particles (ITO particles) with a size (d50) of 3 to 4 pm, based on the total weight of the coating compound, was applied to the preheated surface by roller application.

[0127] The coated concrete element was heated to 80°C for 5-20 seconds and then irradiated with UV radiation at 2000 mj / cm². 2 hardened.

[0128] As an alternative to the silane-based and ITO-containing coating material, 140 g of an acrylate / methacrylate-based coating material comprising 2 wt% titanium dioxide platelets with a size (d50) of 200 to 500 nm, based on the total weight of the coating material, were applied for coating.

[0129] Example 4

[0130] Core concrete mix: 320 kg cement, 950 kg sand, 945 kg gravel and 135 liters water. Facing concrete mix: 440 kg cement, 1030 kg sand, 730 kg colored natural stone chippings, 150 liters water.

[0131] According to the above regulation for the production of two-layer concrete elements, a two-layer concrete element with a density of 2.35 kg / dm³ was produced. 3 produced, with a facing concrete density of 2.32 kg / dm³ 3 amounts.

[0132] After compaction, the surface of the concrete element was finely washed using a high-pressure water washing machine while still uncured. An aqueous acrylate system (45% solids) was sprayed onto the washed surface of the concrete element before it was placed in the curing chamber. The concrete element was then cured in a curing chamber at 25°C and 70% relative humidity for 24 hours. Subsequently, the surface of the concrete element was finished by curling (diamond-tipped brushes) at a hardness of 120, at 600 rpm and a drive energy of 14 amps / l, with a feed rate of 2 m.

[0133] For coating, the surface of the received concrete element was subsequently preheated to 55°C according to the above procedure. 100 g of a silane-based coating material comprising 10 wt% indium tin oxide particles (ITO particles) with a size (d50) of 3 to 4 pm, based on the total weight of the coating material, were applied to the preheated surface as a coating system by roller application.

[0134] The coated concrete element was heated to 80°C for 5-20 seconds and then irradiated with UV radiation at 2000 mj / cm². 2 hardened.

[0135] Example 5

[0136] Core concrete mix: 310 kg blast furnace slag, 90 kg fly ash, 62 kg activator solution (62% solids), 870 kg sand, 1015 kg gravel, and 105 liters of water. Facing concrete mix: 505 kg alkali-activated binder, 94 kg activator solution (50% solids), 1005 kg sand, 603 kg colored natural stone chippings, 19.5 kg color pigment, and 105 liters of water.

[0137] According to the above regulation for the production of two-layer concrete elements, a two-layer concrete element with a density of 2.33 kg / dm³ was produced. 3 produced, with a facing concrete density of 2.31 kg / dm³ 3 amounts.

[0138] The concrete element was then cured in a hardening chamber at 30°C and 90% RH for a period of 24 hours.

[0139] The concrete element surface was then reworked by scraping with a diamond tool and curling (diamond-tipped brushes) of hardness 120, at 600 rpm and a feed rate of 14 amps / l.2m. For coating, the surface of the resulting concrete element was then preheated to 55°C according to the above procedure. 140 g of an acrylate / methacrylate-based coating material comprising 7.5 wt% indium tin oxide particles (ITO particles) with a size (d50) of 3 to 4 pm, based on the total weight of the coating material, were applied to the preheated surface by roller application.

[0140] The coated concrete element was heated to 80°C for 5-20 seconds and then irradiated with UV radiation at 2000 mj / cm². 2 hardened.

[0141] As an alternative to the ITO-containing coating, 140 g of an acrylate / methacrylate-based coating material comprising 1 wt% aluminium oxide platelets with a size (d50) of 3 to 4 pm, based on the total weight of the coating material, were applied.

[0142] Example 6 - Concrete element with facing concrete layer containing microhollow spheres, cement-based

[0143] Example 6.1 Standard facing concrete mix without micro-hollow spheres as a reference: 440 kg white cement, 1400 kg sand, 325 kg quartz crushed stone, 135 liters water, 6.6 kg admixture.

[0144] Example 6.2 Microhollow spheres Variant 1:

[0145] Facing concrete mix: 440 kg white cement, 1390 kg sand, 325 kg quartz crushed stone, 135 liters water, 6.6 kg admixture, 5.5 kg micro hollow spheres

[0146] Example 6.3 Microhollow spheres variant 2:

[0147] Facing concrete mix: 440 kg white cement, 1370 kg sand, 325 kg quartz crushed stone, 135 liters water, 6.6 kg admixture, 27.5 kg micro hollow spheres

[0148] The facing concrete layers according to Examples 6.1 to 6.3 were each combined with a core concrete mix according to Example 1 (cement-based) or 2 (alkaline-activated binder) in accordance with the above procedure for the production of two-layer concrete elements. This resulted in two-layer concrete elements with a density of 2.34 kg / dm³. 3 (Cement) or 2.30 kg / dm³ 3 (alkaline activated binder) produced, with a pre-fabric density of 2.32 kg / dm³ 3 (Example 6.1), 2.29 kg / dm³ 3 (Example 6.2) or

[0149] 2.17 kg / dm³ 3 (Example 6.3) is...

[0150] The concrete element was then cured in a curing chamber at 25°C and 90% RH for a period of 24 hours.

[0151] Subsequently, the concrete element surface was reworked by curling (diamond-coated brushes) of hardness 120, at 600 rpm and 14 amp drive energy / l.2m feed rate.

[0152] For coating, the surface of the received concrete element was subsequently preheated to 55°C according to the above instructions. 140 g of an acrylate / methacrylate-based coating material comprising 1 wt% aluminum flakes with a size of 3 to 4 µm, based on the total weight of the coating material, were applied to the preheated surface as a coating system by roller application.

[0153] The coated concrete element was heated to 80°C for 5-20 seconds and then subjected to UV irradiation at 2000 mJ / cm². 2 hardened.

[0154] The resulting facing concrete layer of Example 6.2 exhibited a pore volume approximately 15 liters larger than the facing concrete layer of Example 6.1 due to the microhollow spheres.

[0155] The resulting facing concrete layer of Example 6.3 exhibited a pore volume approximately 75 l larger than the facing concrete layer of Example 6.1 due to the microhollow spheres.

[0156] Example 7 - Concrete element with facing concrete layer containing microhollow spheres, geopolymer-based. Example 7.1 Standard facing concrete mix without microhollow spheres as a reference: 500 kg alkali-activated binder, 88.6 kg activator solution (solids content 50%), 1300 kg sand, 325 kg quartz crushed stone, 75 liters water, 3.5 kg admixtures

[0157] Example 7.2 Microhollow spheres variant 1: 500 kg alkali-activated binder, 88.6 kg activator solution (solids content 50%), 1300 kg sand, 325 kg quartz crushed stone, 75 liters water, 3.5 kg additive, 5.5 kg microhollow spheres.

[0158] Example 7.3 Microhollow spheres variant 2: 500 kg alkali-activated binder, 88.6 kg activator solution (solids content 50%), 1300 kg sand, 325 kg quartz crushed stone, 75 liters water, 3.5 kg additive, 27.5 kg microhollow spheres

[0159] The facing concrete layers according to Examples 7.1 to 7.3 were each combined with a core concrete mix according to Example 1 (cement-based) or 2 (alkaline-activated binder) in accordance with the above procedure for the production of two-layer concrete elements. This resulted in two-layer concrete elements with a density of 2.33 kg / dm³. 3 (Cement) or 2.29 kg / dm³ 3 (alkaline activated binder) produced, with a pre-fabric density of 2.31 kg / dm³ 3 (Example 7.1), 2.28 kg / dm³ 3 (Example 7.2) or 2.16 kg / dm³ 3 (Example 7.3) is.

[0160] The concrete element was then cured in a hardening chamber at 30°C and 90% RH for a period of 24 hours.

[0161] Subsequently, the concrete element surface was reworked by scraping with a diamond tool and curling (diamond-coated brushes) of hardness 120, at 600 rpm and 14 amp drive energy / l.2m.

[0162] For coating, the surface of the received concrete element was preheated to 55°C according to the above procedure. 140 g of an acrylate / methacrylate-based coating containing 7.5 wt% indium tin oxide particles (ITO particles) with a size (d50) of 3 to 4 pm, based on the total weight of the coating, were applied to the preheated surface by roller application. The coated concrete element was then reheated to 80°C for 5–20 seconds and subsequently cured by UV irradiation at 2000 mJ / cm². 2 hardened.

[0163] The resulting facing concrete layer of Example 7.2 exhibited a pore volume approximately 15 l larger than the facing concrete layer of Example 7.1 due to the microhollow spheres.

[0164] The resulting facing concrete layer of Example 7.3 exhibited a pore volume approximately 75 l larger than the facing concrete layer of Example 7.1 due to the microhollow spheres.

[0165] The densities given in examples 6 and 7 are the densities in the moist storage condition.

[0166] Experiment on the reflection of IR radiation

[0167] The concrete elements in examples 1 to 7 were irradiated with an IR emitter (Etherma SM-S1-PLUS-2000-T) to investigate their IR reflectivity. Additionally, an uncoated concrete element manufactured as in example 2 was also irradiated with the IR emitter. Irradiation durations were 30 seconds, 2 minutes, 5 minutes, and 10 minutes.

[0168] The IR emitter was then switched off, and the heating of the stones was compared using a thermal imaging camera. For each stone with the coating system according to the invention, a temperature was determined to be at least 3°C ​​lower for light surfaces and at least 5°C lower for dark surfaces than for an uncoated reference concrete element, depending on the surface color.

[0169] In addition, the samples were measured with regard to their IR reflection properties. For this purpose, the Optosol Alphameter (Optosol GmbH, Mühlheim im Markgräflerland, Germany) was used. For each stone with the coating system according to the invention, the IR reflection properties were determined to be at least 5% higher for light surfaces and at least 10% higher for dark surfaces than for an uncoated reference concrete element, depending on the surface color.

[0170] Additionally, the samples were measured for thermal conductivity. For this purpose, one side of the samples was heated to a constant temperature of 57°C using a heat exchanger plate. The surface temperature of the opposite side was measured with an infrared camera (FLIR SC620).

[0171] In each case, the stones with the inventive modification of the concrete layer exhibited a thermal conductivity that was at least 8% lower for low additions of microhollow spheres and at least 15% lower for high additions than that of an unmodified stone, depending on the amount of microhollow spheres added.

[0172] Comparative concrete element

Claims

December 23, 2025 Patent claims 1. A building element comprising a layer of stone with a stone surface, characterized in that the stone surface is coated with a reflective coating system, wherein the reflective coating system is essentially concrete-free and is designed to reflect infrared radiation and essentially preserve the optical appearance of the stone surface.

2. Building element according to claim 1, characterized in that the stone layer comprises or consists of artificial stone, wherein the artificial stone comprises a binder.

3. Component according to claim 2, characterized in that the binder is a mineral binder.

4. Component according to claim 2 or 3, characterized in that the binder is cement.

5. Component according to claim 2, characterized in that the binder is a latent hydraulic binder and / or a pozzolanic binder, and / or the artificial stone contains 5 wt.% or less, preferably 3 wt.% or less, cement, further preferably being substantially cement-free.

6. Component according to claim 2, characterized in that the binder is an alkali-activated binder.

7. Component according to claim 2, characterized in that the binder is a resin, in particular a synthetic resin.

8. Building element according to claim 1, characterized in that the stone layer comprises or consists of natural stone.

9. Component according to one of the preceding claims, characterized in that the reflective coating system comprises one, two or more layers.

10. Component according to claim 9, characterized in that the reflective coating system comprises two layers with a difference in refractive index, wherein the difference in refractive index is 0.5 or more, preferably 1.0 or more.

11. Component according to one of claims 9 or 10, characterized in that the reflective coating system comprises two layers with a difference in infrared reflectance, and / or that the coating system comprises a metal layer and a protective layer, wherein the metal layer preferably has a thickness of 250 nm to 4000 nm, more preferably 400 nm to 2500 nm.

12. Component according to one of the preceding claims, characterized in that the reflective coating system comprises or consists of a particle layer which — a binder comprising a silicone resin and / or a poly(meth)acrylate and — Infrared radiation reflecting particles 13. Component according to claim 12, characterized in that the particle layer contains 2 wt.% to 60 wt.%, preferably 5 wt.% to 50 wt.%, more preferably 5 wt.% to 30 wt.%, infrared radiation reflecting particles, based on the total weight of the particle layer, and / or contains 35 wt.% to 98 wt.%, preferably 35 wt.% to 95 wt.%, more preferably 35 wt.% to 90 wt.%, particularly preferably 40 wt.% to 90 wt.%, binder, based on the total weight of the particle layer.

14. Component according to one of claims 12 or 13, characterized in that the infrared radiation reflecting particles are selected from the group consisting of titanium dioxide, zirconium dioxide, cerium oxide, zinc oxide, indium tin oxide, mica, metal particles, wherein the metal is preferably selected from the group consisting of aluminum, copper, zinc, iron, silver and alloys thereof, and mixtures thereof.

15. Component according to one of the preceding claims, characterized in that a primer layer is arranged between the stone surface and the reflective coating system, wherein the primer layer is preferably applied on the wet side (fresh concrete) or the dry side (cured concrete).

16. Component according to claim 15, characterized in that the primer layer is an organic or an inorganic primer layer, in particular an acrylate-based or silicone resin-based primer layer.

17. Building element according to any one of the preceding claims, characterized in that the building element is a stone, in particular a paving stone, a wall element, a facing stone, a step, a roof tile, a facade element or a slab.

18. Method for manufacturing a building element according to any one of claims 1 to 17, comprising the following steps: a. Providing a building element comprising a layer of stone with a stone surface, b. optional pretreatment of the stone surface with an acidifying agent and / or with a primer and / or with a curling brush to obtain a pretreated stone surface, cl. Application of a UV-curable coating material comprising non-functionalized silanes and / or hydrolysates of non-functionalized silanes and / or silicone resins and / or silicones with residues of hydrolyzable alkoxy groups as well as infrared radiation reflecting particles and at least one cationic or anionic UV starter to the stone surface or optionally the pre-treated stone surface, dl. Hardening of the coating material, especially by UV radiation, at a radiation energy of 200 to 2500 mJ / cm² 2 preferably from 500 to 2200 mJ / cm² 2 , preferably from 700 to 2000 mJ / cm² 2, in particular for a duration of 0.1 to 10 s, preferably of 0.5 to 5 s, or c2. Applying a first thin layer, in particular a thin metal layer, to the stone surface, preferably by vapor deposition or sputtering, d2. optionally, applying to the first thin layer a second thin layer with a difference in refractive index to the first thin layer, wherein the difference in refractive index is 0.5 or more, preferably 1.0 or more, or a second thin layer with a difference in infrared reflectance.

19. The method according to claim 18, characterized in that the non-functionalized silanes are selected from the group consisting of 2-, 3- or 4-fold alkoxysilanes without an organic functional group, in particular methyltriethoxysilane (MTES), tetraethoxysilane (TEOS), phenyltriethoxysilane (PHTES), propyltriethoxysilane (PTES), dimethyldiethoxysilane (DMDES), methyltrimethoxysilane (MTMS), tetramethoxysilane (TEMOS), tetra-n-propoxysilane, tetra-n-butoxysilane, phenyltrimethoxysilane (PHTMS), propyltrimethoxysilane (PTMS), dimethyldimethoxysilane (DMDMS), isobutyltriethoxysilane, isobutyltrimethoxysilane, octyltriethoxysilane, octyltrimethoxysilane, iso-octyltriethoxysilane, iso-octyltrimethoxysilane, isooctyltriethoxysilane, isooctyltrimethoxysilane Hexadecyltrimethoxysilane, hexadecyltriethoxysilane, 1,2-bis(triethoxysilyl)ethane, 1,2-bis(trimethoxysilyl)ethane, trimethylethoxysilane, trimethylmethoxysilane, (cyclohexyl)methyldiethoxysilane, cyclohexyl)methyldimethoxysilane,Dicyclopentyldiethoxysilan, Dicyclopentyldimethoxysilan, Cyclohexyltrimethoxysilan, Cyclopentyltrimethoxysilan, Ethyltrimethoxysilan, Phenylethyltrimethoxysilan, Phenyltrimethoxysilan, n-Propyltrimethoxysilan, Dimethyldimethoxysilan, Diisopropyldimethoxysilan, Phenyimethyldimethoxysilan, Phenylethyltriethoxysilan, Phenylmethyldiethoxysilan und Phenyldimethylethoxysilan., 20. A method according to any one of claims 18 to 19, characterized in that the UV starter is a cationic UV starter selected from the group consisting of (4-methylphenyl)[4-(2-methylpropyl)phenyl]iodonium hexafluorophosphate, triarylsulfonium hexafluorophosphate, bis[4-diphenylsulfoniumphenyl]sulfide bishexafluoroantimonate, thiophenoxyphenylsulfonium hexafluoroantimonate, thiobis(4,1-phenylene)-S,S,S',S'-tetraphenyldisulfonium bishexafluorophosphate, diphenyl(4-phenylthiophenyl)sulfonium hexafluorophosphate, (4-{[4-(diphenylsulfanylium)phenyl]sulfanyl}phenyl)diphenylsulfonium bishexafluorophosphate, (thiodi-4,1-phenylene)-bis-(diphenylbis)(OC-6,1 1)hexafluoroantimonate, Diphenyl[4-(phenylthio)phenyl]sulfonium hexafluoroantimonate, bis-(4-dodecylphenyl)iodonium hexafluoroantimonate, thiobis(4,l-phenylene)-S, S, S', S'-tetraphenyldisulfonium bishexafluorophosphate;diphenyl(4-phenylthiophenyl)sulfonium hexafluorophosphate, phenyl-p-octyloxyphenyliodonium hexafluoroantimonate, bis(dodecylphenyl)odonium hexafluoroantimonate, bis(4-methylphenyl)iodonium hexafluorophosphate, diphenyl(4-phenylthio)phenylsulfonium hexafluoroantimonate and (Thio-4,1-phenylene)bis(diphenylsulfonium)dihexafluoroantimonate).; 21. Method according to any one of claims 18 to 20, characterized in that the UV starter is an anionic UV starter selected from the group consisting of aryldiazonium compounds or ketoprofen-type compounds such as 1,3-Di-4-piperidylpropanedi(a-(2-benzoyl)phenylpropionate), 1,6-Hexamethylenediaminedi(a-(2-benzoyl)phenylpropionate) and 9-DBU(2-benzoylphenylpropionate).

22. Method according to claim 18, characterized in that the metal layer is an aluminum layer.

23. Method for manufacturing a component according to any one of claims 1 to 17, comprising the following steps: a. Providing a building element comprising a layer of stone with a stone surface, b. optional pretreatment of the stone surface with an acidifying agent and / or with a primer and / or with a curling brush to obtain a pretreated stone surface, c3. Application, preferably by spraying, of a coating material in the form of an aqueous emulsion comprising at least one acrylic polymer and infrared-reflecting particles onto the stone surface or optionally the pretreated stone surface. d3. Curing of the coating material at a surface temperature of 15°C to 80°C, preferably 30°C to 70°C, more preferably at 45°C to 65°C, in particular by IR radiation, especially for a duration of 10 seconds to 10 minutes, more preferably 10 seconds to 30 seconds, and / or by UV radiation with 500 to 2500 mJ / cm². 2 .

24. Method for manufacturing a component according to any one of claims 1 to 17, comprising the following steps: a. Providing a building element comprising a layer of stone with a stone surface, b. optional pretreatment of the stone surface with an acidifying agent and / or with a primer and / or with a curling brush to obtain a pretreated stone surface, c4. Providing a coating material comprising at least one acrylic polymer and IR-reflecting particles, preferably with a viscosity of 50 to 300 mPas, more preferably 100 to 250 mPas, more preferably 100 to 200 mPas, d4. Applying the coating material to the surface by rolling, e4. Curing of the coating material at a surface temperature of 130°C to 220°C, in particular by IR radiation, especially for a duration of 10 seconds to 10 minutes, preferably 10 seconds to 30 seconds, and / or by UV radiation with 500 to 2500 mJ / cm² 2 .

25. Method for manufacturing a component according to any one of claims 1 to 17, comprising the following steps: A. Providing an artificial stone mixture in a mold, wherein the artificial stone mixture has a mixing surface, B. optionally pretreating the mixture surface with a primer to obtain a pretreated mixture surface, C1. Applying, in particular spraying, a UV-curable coating material comprising non-functionalized silanes and / or hydrolysates of non-functionalized silanes and / or silicone resins and / or silicones with residues of hydrolyzable alkoxy groups as well as infrared-reflecting particles and at least one cationic or anionic UV starter to the mixture surface or optionally the pretreated mixture surface, D1. Curing of the artificial stone mixture, E1. Hardening of the coating material, especially by UV radiation, at a radiation energy of 200 to 2500 mJ / cm² 2 preferably from 500 to 2200 mJ / cm² 2 , preferably from 700 to 2000 mJ / cm² 2 , in particular for a duration of 0.1 to 10 s, preferably of 0.5 to 5 s or C2. Applying, in particular spraying, a coating material in the form of an aqueous emulsion comprising at least one acrylic polymer and infrared radiation reflecting particles to the stone surface or optionally the pretreated stone surface, D2. Curing of the artificial stone mixture, E2. Curing of the coating material at a surface temperature of 15°C to 80°C, preferably 30°C to 70°C, more preferably at 45°C to 65°C, in particular by IR radiation, especially for a duration of 10 seconds to 10 minutes, preferably 10 seconds to 30 seconds, and / or by UV radiation with 500 to 2500 mJ / cm² 2 .

26. Use of a building element according to one of claims 1 to 17 as a floor covering for residential environment design.

27. Building element according to one of claims 1 to 7 or 9 to 17, characterized in that the stone layer comprises or consists of concrete.

28. Building element according to claim 27, characterized in that the stone layer comprises a facing concrete layer.

29. Component according to claim 28, characterized in that the facing concrete layer contains microhollow spheres, preferably in an amount of 1 to 100 kg / m² 3 , preferably 1 to 50 kg / m² 3 , particularly preferably 5 to 50 kg / m² 3 , most preferred 5 to 30 kg / m² 3 , based on the total volume of the facing concrete layer, and / or preferably micro hollow spheres with a total volume of 1 to 300 l / m³ 3 , preferably, 1 to 150 l / m² 3 , especially preferably 10 to 100 l / m² 3 , most preferred 15 to 75 l / m 3 , relative to the total volume of the facing concrete layer.

30. Building element according to one of claims 28 or 29, characterized in that the stone layer has a core concrete layer arranged below the facing concrete layer, wherein the core concrete layer contains micro-hollow spheres in an amount of 1 to 100 kg / m² 3 , preferably 1 to 50 kg / m² 3 , preferably 5 to 50 kg / m² 3 , especially preferably 5 to 30 kg / m² 3 , based on the total volume of the core concrete layer, and / or contains microhollow spheres with a pore volume of 1 to 300 l / m³ 3 , preferably, 1 to 150 l / m² 3 , especially preferably 10 to 100 l / m² 3 , most preferred 15 to 75 l / m 3 based on the total volume of the core concrete layer.

31. Building element according to one of claims 28 to 30, characterized in that the stone layer comprises a core concrete layer arranged below the facing concrete layer, which comprises aggregates, in particular in an amount of 50 to 90 wt.%, more preferably 55 to 90 wt.%, based on the total weight of the core concrete layer, wherein the aggregate preferably has a grading curve coarser than C8 according to DIN 1045, or that the aggregate has a grain size distribution such that in a sieve test 10 to 45 wt.% remain on the 1.0 mm sieve, 3 to 10 wt.% on WO 2026 / 139624 - 10 PCT / EP2025 / 089022 the 500 μm sieve and 3 to 5 wt.% remain on the 125 μm sieve, based on the total weight of the aggregate.