DE102014220798A1 - Hydrophilically coated insulating glass for greenhouses - Google Patents

Abstract

The present invention relates to an inside hydrophilically coated insulating glass for greenhouses and a greenhouse system comprising such a coated insulating glass.

Description

The present invention relates to an inside hydrophilically coated insulating glass for greenhouses and a greenhouse system comprising such a coated insulating glass.

The use of insulating glass for greenhouses is basically known. Due to rising heating energy costs, it is becoming increasingly financially attractive to use insulating glass in the greenhouse sector with its large glass surfaces.

In addition to the high production costs, however, insulating glasss have the disadvantage that they have a lower light transmittance and thus associated with a reduced yield.

Insulating glass has the advantage that the condensation of water on the inside of the greenhouse is reduced because the windows do not cool off so much in cool weather and especially at night. As a result, an advantageously increased humidity for the plants can be realized.

However, it has been shown in the application that, despite the improved thermal insulation of insulating glass, its use in the greenhouse area leads to the condensation of moisture on the inner surface. This condensation is explained by the extremely high humidity, as it can be achieved in a greenhouse with insulating glass. Moisture condensation is not only observed in cool weather or at night, but also during the day. The condensed moisture (when present in droplet form on the inside of the insulating glass) reduces the light transmission and thus the plant growth. In addition, in the worst case, drops from the roofside glass surfaces may fall on the plants and, especially in plants such as tomatoes, be detrimental to growth and plant health.

It should be emphasized here that just insulating glass is a complex system with many individual components such as glasses, coating, spacer frame or gas filling, the individual components can influence each other depending on the configuration. In addition, since greenhouse systems involve complex and sometimes conflicting requirements with respect to the glass, such as safety, translucency, thermal insulation, cost, or light diffusion, the development of improved green glass insulation presents a major challenge.

This is where the invention, which is based on the object to provide an insulating glass, which overcomes the disadvantages of the prior art and a reduced light reduction due to condensation combined with the necessary properties for a greenhouse.

This object is achieved according to the invention by the subject of the main claim. Specific embodiments of the invention are the subject of the additional dependent or independent claims.

Summary of the invention

In a first aspect, the invention provides an insulating glass for greenhouses consisting of at least two spacers ( 1 ) through an air- or gas-filled gap ( 2 ) separate glass panes ( 3 . 4 ) which are hermetically sealed in the edge area ( 5 . 6 ), wherein on the greenhouse side surface of the insulating glass, a chemically and mechanically resistant hydrophilic layer ( 7 ) is arranged.

As the inventors have found out, in the case of an insulating glass which can be used in a greenhouse, the problem of condensation on the inside can be prevented in a surprisingly good manner by a chemically and mechanically resistant hydrophilic layer.

Here, drops are spread flat in shape and / or form a film of water on the glass surface. These advantageous condensation events occur even in the obliquely or even horizontally located glass surfaces, in which the risk of drop formation is particularly great.

In the case of the coating according to the invention, it was found that the moisture condensing out more readily accumulates on the surface as a film-shaped layer. Such a formation of a water film facilitates the evaporation of the water and thus the rapid restoration of an almost anhydrous Surface. As a result, the optimal growth conditions predetermined by the insulating glass are restored accordingly quickly.

Compared to an uncoated glass, the hydrophilic inner coating clearly improves the growth conditions.

Such a hydrophilic coating surprisingly shows no moisture-related functional losses despite the permanently present, extremely high humidity, as can be observed in greenhouses with insulating glass.

Another advantage is the fact that there are numerous strategies and substances for the production of hydrophilic coatings, which can be used specifically based on the specific requirements.

Another advantage is that there is the possibility of a hydrophilic retrofit. An existing insulated glass greenhouse can be significantly improved by appropriate hydrophilic treatment of the inner surfaces.

Such an easily accessible inside coating can also be renewed or modified after installation.

Finally, the application of such a hydrophilic coating is a cost-effective and easy to carry out measure.

Detailed description of the invention

The insulating glass can be made up of two, three or more panes. Preference is given to an insulating glass composed of two panes, since it represents a good compromise between the required thermal insulation and cost.

In one embodiment of the invention, the gas-filled or air-filled inter-pane space may also have embedded therein a polymer film or polymer plate which preferably extends as far as the edge regions of the insulating glass and is particularly preferably sealed at the edge regions. In this embodiment, the insulating glass contains an additional polymer disk, which are designed as a film or plate. As polymers in this case polyacrylate or polycarbonate is preferred.

In principle, all layers known to the person skilled in the art are suitable as hydrophilic layers, provided, on the one hand, they have the required properties such as high transmission in the visible and infrared spectral range and color neutrality in transmission and reflection, and, on the other hand, the required chemical and mechanical resistance.

In the insulating glass according to the invention, in one embodiment, the hydrophilic layer can be applied to the glass itself, or it can be arranged on a film which is laminated on the greenhouse-side surface of the insulating glass.

In one embodiment of the invention, the hydrophilic layer is based on inorganic substances, preferably oxides or organic polymers or mixtures thereof.

As oxides in this case SiO, SiO ₂ , TiO ₂ or WoO are preferred.

For the construction of the hydrophilic layer, it is possible to use all polymers which carry polar or electrically charged functional groups and can therefore form hydrogen bonds with the water molecules on their surface. As a result, this can absorb water so that the resulting water condensation in the fine droplets of water are absorbed by the layer within a short time.

Suitable hydrophilic polymers include polyacrylate and other polyelectrolytes, polyacrylamides, polyurethanes, and polyesters (especially based on maleic anhydride monomers.) Polar functional groups may also include amine groups. "" Corresponding amine-functional polymers include polyallylamine (PAAm), polyallylamine hydrochloride (PAH). , Polyethyleneimine (PEI), and N-substituted polyethyleneimine.

In a preferred embodiment, the hydrophilic polymer used is a polyurethane polymer which contains oxyethylene chains and has a water absorption capacity of between 10 and 40%, moreover contains a nonionic, oxyethylene chain-containing surfactant. Corresponding polymers and hydrophilic coatings formed therefrom are known in the EP 2 062 881 A1 which is hereby incorporated by reference and therefore forms part of the disclosure.

In addition, it is also possible to use natural polymers, preferably in modified form, such as, for example, polysaccharides, polypeptides and copolymers thereof. Preferred here is a starch-based polymer. This starch-based material is preferably a hydrolyzate of a starch-acrylonitrile graft polymer or a starch-acrylate polymer.

The use of cellulose-based polymers is also possible, so here a cellulose-acrylonitrile graft polymer or carboxymethyl cellulose can be used.

Further, the following polymers are useful for the hydrophilic coating: polyacrylamide, polyethers such as polyacrylates, polyacylalkyleneimine, polyalkyleneoxide-polycarboxylic cross-linked product, polyallyl diglycolcarbonate (CR39, PADS), polycarbonate, polycycloolefin, poly (ethylene-old-maleic acid), polyethylene oxide, polyethylene oxide -Co-polypropylene oxide block copolymer, polyethersulfone, polyethylene glycol or polyethylene glycol diacrylate, polyhydroxyalkyl acrylates such as (homo) polymers of hydroxyethyl methacrylate (HEMA), hydroxyethyl acrylate, hydroxypropyl acrylate, polyethylene terephthalate (PET), polyimines, poly (N, N-dialkylacrylamide ), Polymethylmethacrylate (PMMA), polyols, polyoxazoline, polysorbates, polythiourethane, polyvinyl alcohol, polyvinylacetal, polyvinylacetate, poly (vinylether), polyvinylpyrrolidone, polyvinylpyridine, polyurethane, a cross-linked polyurethane resin preparable by reaction of polyisocyanate with polyetherpolyol or polyesterpolyol, Sty rolacrylonitrile or triacetyl acetate. These include mixtures or copolymers of two or more of the polymers listed above.

Particularly suitable for a hydrophilic coating are polyionic molecules such as polyallylammonium, polyethylenimine, polyvinylbenzyltrimethylammonium, polyaniline, sulfonated polyaniline, polypyrrole, polypyridinium, polythiophene-acetic acids, polystyrene-sulfonic acids, polymers and copolymers of zwitterions and salts thereof.

In one embodiment of the invention, the composition used for coating consists of a UV-curable composition comprising 70-95% by weight of a mixture of polyalkylene oxide di (meth) acrylates. Such compositions are in the European patent application EP 1 118 646 A1 described, the disclosure of which is hereby incorporated in full in the present application.

In a further embodiment of the invention, the composition used for coating consists of a UV-curable mixture comprising 40-80% by weight of an acrylate or methacrylate monomer, 20% to 60% by weight of a short-chain acrylate ester or methacrylate ester monomer, a crosslinking reagent and a polymerization initiator. Such compositions are in the U.S. Patent No. 5,480,917 described, the disclosure of which is hereby incorporated in full in the present application.

Hydrophilic polymers and corresponding methods for forming hydrophilic layers are also disclosed in U.S. Pat EP 1944 277 A1 and the EP 2 256 153 A1 described. These documents are hereby incorporated by reference and thus are considered part of the disclosure.

The hydrophilic polymer coating can also be applied to a nanostructured surface, as is typical for hydrophobic surfaces. In this way, a structurally designed as a hydrophobic glass surface can be inverted in their property. A corresponding coating method and suitable polymers are the subject of the US application US 2008/0199657 A1, the disclosure of which is hereby incorporated in full.

In one embodiment of the invention, the coating comprises a polymer and an inorganic substance. Preferred here are 95-99.5 wt .-% of a polymer from the group containing, hydroxypropylcellulose, polyvinyl alcohol, Polyvinyalacetal, polyvinylpyrrolidone, polyvinyl acetate and 0.5-5 wt .-% of an inorganic silicon compound, which is preferably amorphous silicon. Such compounds are used in the EP 1 477 466 A1 discloses the disclosure of which is fully incorporated in the present application.

The hydrophilic coating can also be composed of several individual layers. In this case, a good adhesion to the glass surface can be achieved by a corresponding lower layer. A hydrophilic topcoat then imparts hydrophilic properties to the surface. The advantage here is that the respective layers are each adapted specifically to the requirements. The underlayer is primarily adjusted to the adhesion and the topsheet primarily to the hydrophilicity, so that superhydrophilic layers with high durability and abrasion resistance can be produced thereby.

The multilayer structure can also be produced by the alternate deposition of polycations and polyanions. Thus, the glass can be given a positively charged surface by a first silane treatment, which is then dipped in a solution with a polyanion and then dipped in a solution with a polycation. The thickness and the conformation of the respective polymer single layers can be determined by the chemistry and the concentration of the deposition solution. Corresponding coatings are in the U.S. Patent No. 5,208,111 described, the disclosure of which is hereby incorporated in full in the present application.

In one embodiment of the invention, the coating has a sub-layer based on TiO ₂ and coated with a thin hydrophilic outer layer. This hydrophilic outer layer should carry a high density of hydroxyl groups, and accordingly, a silica-based layer which is particularly doped with aluminum or zirconium atoms is preferred. Correspondingly structured coatings are the subject of US application US 2008/0241479 A1, the disclosure of which is hereby incorporated in full in the present application.

Furthermore, it is also possible that the coating comprises a photocatalytic semiconductor material such as titanium dioxide, ZnO, SnO ₂ , SrTiO ₃ , WO ₃ , Bi ₂ O ₃ or Fe ₂ O ₃ , which is converted by UV excitation into a hydrophilic coating. Such hydrophilic coatings are the subject of EP 1 712 531 A2 , the disclosure of which is hereby incorporated in full in the present application.

In one embodiment of the compound, the hydrophilic coating may be formed by a stable and smooth layer of uniformly dispersed sintered metal oxides. ZnO, SiO ₂ , rutile TiO ₂ , or anatase TiO ₂ are preferably used here as metal oxides. Such a coating can, for example, according to the PCT application WO2009 / 092664 The glass is coated with a film of metal oxide nanoparticles crosslinked by an organic binder. In a subsequent hot sintering process, the organic binder is decomposed and the nanoparticles are sintered into a uniformly structured layer. The above PCT application is hereby incorporated by reference and thus forms part of the disclosure.

In a further embodiment, the hydrophilic coating comprises a mixture of porous inorganic fine particles and an inorganic oxide as binder component. Preferably, this mixture is accompanied by an organic polymer as further binder component. The inorganic fine particles preferably consist of a metal oxide such as ZnO, SnO ₂ , SiO ₂ , TiO ₂ , Ce ₂ O ₃ , ZrO ₂ , Fe ₂ O ₃ or zeolite, of a metal carbide such as SiC or of a metal nitride such as Si ₃ N ₄ . Corresponding coatings are the subject of the European application EP 2 698 246 A1 , the disclosure of which is hereby incorporated in full in the present application.

The covalent attachment of the hydrophilic polymers can be carried out by customary methods known to the person skilled in the art, such as, for example, in US Pat WO 2007/021180 described. This document is hereby incorporated by reference and thus forms part of the disclosure.

Thus, both conventional wet chemical methods and methods such as chemical vapor deposition (CVD), plasma deposition, plasma enhanced chemical vapor deposition (PACVD) or plasma polymerization can be used.

Also, silicon compounds such as siloxanes can be used as a hydrophilic coating material.

For the construction of the hydrophilic layer also organosilicon compounds can be used. These preferably carry acryloyl groups and sulfonate groups. Corresponding examples are in EP 2 256 153 A1 discloses the content of which is fully incorporated in the disclosure of the present application.

Mixed polymers of silicones and organic polymers may also be used, such as acrylic-silicone resins, block copolymers of silicone and acrylates.

The structure of hydrophilic organosilicon layers can also be done in two steps. Thus, first of all a silanol can be applied which carries hydrolyzable groups (such as, for example, an alkoxy or an acyloxy group) and reacts with another hydrophilic organic substance to form a hydrophilic layer. As the hydrophilic organic compound, we preferably use a hydrophilic surfactant which preferably contains poly (oxyalkylene) groups. Corresponding compounds with their use are in the PCT application WO2011 / 080472 which is hereby incorporated in its entirety with its disclosure as a reference and thus as part of the disclosure.

Multilayered hydrophilic coatings are also used in the EP 1 923 363 A2 The disclosure of which is hereby incorporated in full in the present application.

Conveniently, the hydrophilic layer may be formed by the glass surface itself insofar as it forms a hydrophilic surface by an appropriate treatment (e.g., etching). Such a hydrophilized glass also has an advantageous UV transmission, as is required for insects in the context of pollination.

For the (on) etching of the glass surface, the person skilled in numerous corrosive substances and mixtures are available. It is preferable to use a fluorine-containing agent such as hydrofluoric acid (aqueous solution of hydrogen fluoride), H ₂ SiF ₆ (hexafluoridosilicic acid) or H ₂ TiF ₆ .

The surface treatment of the glass may also be a more complex structural change of the surface. Thus, the glass can form a hydrophilic surface by forming a convex-concave surface structure. This structure preferably has a spacing of the respective convex or concave structures of 0.2 to 50 μm.

In one embodiment of the invention, the hydrophilically coated surface of the insulating glass has a contact angle against water of less than 40 °, preferably less than 35 ° and especially less than 30 °. In these contact angles occurring according to the invention, the tendency to drop formation is greatly reduced and the water will accumulate more easily as a film-shaped layer on the surface. Such a formation of strongly flattened drops or a water film facilitates the evaporation of the water and thus the rapid restoration of an almost water-free surface. As a result, the optimal growth conditions predetermined by the insulating glass are restored accordingly quickly.

Preference is given to using inorganic substances having hydrophilic properties, in particular oxides or oxide mixtures such as, for example, SiO ₂ , SiO ₂ , TiO ₂ or WoO. These may usefully be incorporated in a binder matrix. In this form they inherently have a better long-term stability over polymers.

In a preferred embodiment of the invention, the hydrophilic layer is formed as an antireflection layer.

Such an antireflection layer can be formed, for example, in that the hydrophilic layer has a reflection-reducing nanostructure as polymer layer on its surface. In a preferred manner, this nanostructure, which can be produced in particular by means of a plasma etching process, extends from the surface of the hydrophilic polymer layer to a depth of 50 nm or more into the polymer layer. Accordingly nanostructured hydrophilic surfaces are from the WO2008 / 104150 known, which is hereby fully incorporated by reference.

An inventively usable plasma etching is known from the patent DE 10241708 The disclosure of which is hereby incorporated by reference.

Another possibility for forming a hydrophilic antireflection layer is the application of SiO ₂ layers with open or closed porosity. By varying the porosity over the layer thickness, a refractive index gradient with AR properties is achieved, wherein the SiO ₂ content of the layer leads to a hydrophilization. Such layers can be applied as a solution, dried and baked in a tempering process, the final properties being achieved only after firing during the tempering process. Another possibility is the application of appropriate Precursor layers on the glass by vacuum deposition processes, wherein the deposited layer or layers after tempering (biasing) achieve their functionality. The deposition of SiO ₂ layers with a porosity gradient (and thus refractive index gradients) can also take place in a manner in a vacuum deposition system, such that the resulting layer has the desired properties even without subsequent tempering of the substrate. For this purpose, the common vacuum deposition methods such as PVD, PE-CVD, PACVD, remote plasma CVD, etc. are suitable.

In one embodiment of the invention, the insulating glass has a light transmittance τ _V according to DIN standard EN 410 greater than 75%, preferably greater than 80% and most preferably greater than 85%. Embodiments of insulating glass according to the invention with low iron content in the glass mass and anti-reflective layers on the levels 1, 2, 3 and 4 (wherein an AR layer with hydrophilic properties is applied to 4) have a light transmission τ _V according to DIN standard EN 410 of more than 83%, preferably more than 85%, and more preferably more than 90%.

Especially with insulating glass, the light transmission is a critical parameter. Of course, when using multiple glass panes, the light transmittance decreases by up to 10-15% compared to single (float) glass. For example, a 1% reduction in light transmission results in a 1% reduction in crop yield. Therefore, measures that result in little improvement in light transmission can lead to significant increases in yield.

The skilled person is familiar with numerous strategies to increase the light transmission of the insulating glass. Thus, the glass sheet thickness can be reduced and / or the iron oxide content of the glass can be reduced.

Particularly advantageous is the coating of the glass with an antireflection layer, as this significantly reduces the reflection of the glass surface. By way of example, by using a suitable AR layer, the reflection at the surface of the glass, for example in the visible region of the sunlight spectrum (380-780 nm), can be reduced from 4% to less than 1%. This leads to a corresponding increase in light transmission by the same amount. If both sides of a glass are provided with corresponding AR layers, this can lead to a transmission increase of more than 6% (as explained above for one-sided antireflection coating). It should be noted that antireflection coatings are always optimized for a specific, desired wavelength range. Antireflective coatings based on a refractive index gradient (eg porous SiO ₂ films with a porosity gradient) normally have the property of reflecting a much larger wavelength range (350 -> 1200 nm) than typical multilayer interference systems, as are known from the field of ophthalmic glass or architectural glass , The reduction of the reflection (one-sided) can be between 1% and nearly 4% (eg 3.5%), depending on the quality, wavelength range, embodiment and requirement of the coating.

In a preferred embodiment of the invention, the insulating glass according to a τ _UV value DIN standard EN 410 greater than 10%, preferably greater than 40% and most preferably greater than 60%. The UV permeability is beneficial for crops that need to be pollinated by insects. These insects need the UV _A light to detect the flowers. Thus, in an inventive UV-transparent insulating the pollination of the plants is facilitated, which is associated with a higher yield.

In a preferred embodiment of the invention, at least one and preferably all glass panes of the insulating glass have an iron oxide content (Fe ₂ O ₃ ) of less than 0.05% by weight, preferably less than 0.02% by weight, more preferably less as 100 ppm The ppm data are determined by means of X-Ray fluorescence (XRF) (eg with the S8 LION device from Bruker Nederland BV, Wormer, NL). A very low proportion of iron oxide in the glass causes a high light transmission and low intrinsic color.

In the case of the insulating glass, the glass panes expediently have a thickness in the range from 2 to 10 mm, preferably from 2 to 6 mm and particularly preferably 4 mm.

Due to the thickness of the glass sheets used, the desired transmission for the greenhouse can be set. Thinner glass panes enable a higher transmission. However, care should be taken when using thinner glass panes that sufficient mechanical stability of the glazing is maintained.

In a further embodiment of the invention, the insulating glass has a thin metal or metal oxide coating on at least one of the glass panes. Through such a layer becomes the emissivity reduced of the glass. Therefore, it is also referred to as a low-E layer (for low emissivity). It should be noted here that not only the emissivity, but also the overall energy transmittance, the light transmittance LT, (percentage of the continuous radiation range of 380-780 nm), the degree of light reflection (percentage of the outside) of the type of metal or metal oxide coating reflected radiation range of 380-780 nm), the UV transmittance (percentage of the continuous radiation range of 280-380 nm) and the color rendering index Ra are affected.

Such a low-E coating is preferably applied to the greenhouse glass pane according to the invention for greenhouse on the greenhouse side pane to the space between the panes (SZR).

In a preferred embodiment of the invention, the insulating glass detects a degree of light diffusion ASTM D 1003 of more than 20%, preferably more than 40% and most preferably more than 60%. Through an insulating glass with increased light diffusion, the light can reach deeper plant parts and also can be prevented from burning on the plants so that less measures to shade the plants must be made. Thus, especially in a rainy summer with low solar radiation in greenhouses with diffuse light input increased productivity can be achieved.

Numerous methods are known to those skilled in the art in order to increase the degree of light diffusion in glasses. This can be achieved, for example, by one or more of the following measures: roughening the glass surface, introducing light-scattering structures during glass shaping, so-called cast glass, targeted etching of the glass ("satined glass") or sandblasting the glass surface, a frosted glass pane, incorporation of pigments into the glass Glass, application of pigments to the glass surface, use of opaque glass, coating of the glass surface with a light-scattering polymer layer or use of light-deflecting / scattering inserts in the SZR (glass or polymer cavity (eg PMMA or PC) Increasing the light scattering and the bonding film have light-scattering additives or properties and thus increase the overall light scattering of the laminated glass.

In the context of the invention, laminated glass is composed of a laminate of at least two glass panes with at least one bonding film which, for example, consists of polyvinyl butyral (PVB), ethylene vinyl acetate (EVA) or ionomers (see Sentry glass from Dupont).

In the context of the invention, at least one, but also several or even all of the glass panes of the insulating glass can thus constitute a laminated glass with a light-scattering connecting film.

In a preferred embodiment of the invention, the insulating glass according to a U-value DIN EN 673 of less than or equal to 3 W / (m2K), preferably less than or equal to 1.6 W / (m2K), more preferably less than or equal to 1.3 W / (m2K). A corresponding reduction in the U value ensures better thermal insulation of the greenhouse, which is accompanied by lower energy consumption. In view of the rising energy costs, this is an extremely important factor for an economically advantageous cultivation of crops.

In the case of the insulating glass according to the invention, the glass panes are expediently made of toughened safety glass (ESG) or partially tempered glass (TVG). As a result, the risk of injury, which is a significant problem especially in greenhouses with glass roofs, significantly reduced and due to the hard glass and large glass sizes are possible.

In a particularly preferred embodiment of the invention, a hydrophobic layer is arranged in the insulating glass on the outside pane surface of the insulating glass. Such a layer prevents wetting of the glass surface with water, wherein the water droplets have a high contact angle. Due to the water-repellent surface created with it, water droplets with a high contact angle (greater than 60 °) form, which can then roll off easily.

In addition to their water-repellent effect, hydrophobic surfaces are usually characterized by a self-cleaning effect, since the soiling of surfaces is closely linked to the wettability of the surface by liquid. In addition, corrosion of the surface or infestation with microorganisms and growth of algae, lichens, mosses and the like is prevented by a hydrophobic surface.

As the inventors have found, the hydrophobic outer coating interacts synergistically advantageously with the hydrophilic inner coating. Due to their shape, the external drops act as light collectors, which guide light into the greenhouse even at small angles of incidence. The hydrophilic layer on the inside, however, leads to a condensation film, which in turn acts as an antireflection layer due to the low refractive index of the water and can efficiently direct the light obtained by the hydrophobic layer into the greenhouse.

Such interaction is also ideally adapted to the daily rhythm. Thus, during the night, the cooling of both the outside temperature and the internal temperature of the greenhouse results in the condensation of water on the inside and outside of the greenhouse. By the morning (sun) light more light can be captured due to the above-described magnifying effect of the externally positioned drops and better be introduced through the water film on the hydrophilic inside of the insulating glass in the greenhouse. Due to the increased light input, the greenhouse heats up faster, which leads to earlier evaporation of both the water film on both the inside and on the outside of the glazing. Overall, the greenhouse is thus placed earlier in its optimal "operating state" and the effect of the applied antireflection layers comes earlier to fruition, which is associated with increased crop yields, especially in cooler weather.

In principle, all layers known to the person skilled in the art are suitable as hydrophobic layers, provided, on the one hand, they have the required properties such as high transmission in the visible and infrared spectral range and color neutrality in transmission and reflection, and, on the other hand, the required chemical and mechanical resistance.

Suitable coating materials include inorganic as well as organic polymers.

As hydrophobic polymers, for example, the following polymers are suitable: polysiloxane, perfluoropolyethers and other fluoropolymers, polystyrene, polyoxypropylene, polyvinyl acetate, polyoxybutylene, polyisoprene, polybutadiene, polyvinyl chloride, polyalkyl acrylate, polyalkylene methacrylate, polyacyl nitrile, polypropylene, polyethylene, polytetrahydrofuran (PTHF), polymethacrylates, polyacrylates, Polysulfones, polyvinyl ethers, poly (propylene oxide) and copolymers thereof.

The hydrophobic layer can be composed of two or more individual layers (so-called "multilayer"). Thus, a hydrophobic substance, preferably an organic perfluoro compound bearing reactive groups, can be bonded to a subbing layer which preferably comprises a reactive silane compound, and more preferably an isocyanate-silane compound. Corresponding hydrophobic multilayers are the subject of the European application EP 0 759 413 A1 , the disclosure of which is hereby incorporated in full.

In a further embodiment of the invention, the composition used for the hydrophobic coating comprises a fluoropolymer bearing functional groups, a curing agent suitable for crosslinking this fluoropolymer, and an oligomer of a tetrafunctional hydrolyzable silane compound. Corresponding mixtures and hydrophobic coatings formed therefrom are known in the EP 0 661 358 A1 which is hereby incorporated by reference and therefore forms part of the disclosure.

In an alternative embodiment, a two-layered hydrophobic coating is formed by applying a first liquid, nonaqueous composition comprising a poly (alkoxy (half) metal oxane) and a finely divided material to which is then applied a second liquid composition comprising at least one fluoro-organic substance Contains (per) fluoroalkyl groups. Corresponding mixtures and hydrophobic coatings formed therefrom are in the German application DE 102 61 285 A1 which is hereby incorporated by reference and therefore forms part of the disclosure.

With the different layers of the hydrophobic coating each different hydrophobing strategies can be followed. Thus, the lower layer can form a rough surface by the formation of tiny depressions and bulges, which already has hydrophobic properties in the sense of a "lotus effect". On this rough layer, a layer can then be applied, which contains a hydrophobic polymer and thus the hydrophobicity can be increased even further. Corresponding mixtures and hydrophobic coatings formed therefrom are in the European application EP 1 449 642 A1 which is hereby incorporated by reference and therefore forms part of the disclosure.

In a further embodiment, in the case of the hydrophobic double layer, a lower layer is produced by sintering spherical fine metal oxide particles, onto which then a mixture of hydrophobicized metal oxide fine particles and a metal oxide binder is applied. Corresponding mixtures and hydrophobic coatings formed therefrom are in the European application EP 2 116 518 A1 which is hereby incorporated by reference and therefore forms part of the disclosure.

In one embodiment of the invention, the hydrophobic coating is designed so that drops of water can easily slide off. This can be achieved, for example, by an arrangement in which a rigid, abrasion-resistant layer is applied to the glass surface, which has depressions and elevations and in which the depressions are at least partially filled with a hydrophobic, water-repellent layer. A corresponding coating is the subject of the European application EP 1 600 429 A1 , which is hereby incorporated by reference and thus forms part of the disclosure.

A preferred embodiment of the invention is an antireflection layer with inherently hydrophobic or else an antireflection layer, which is provided with a hydrophobic coating, wherein the hydrophobic layer is designed so that the antireflection properties of the AR layer only to a small extent or ideally not at all For example, typical hydrophobic fluoropolymer-based coatings applied after pre-stressing are so thin (max. a few nm) that a change in the optical values of the AR coating is not observed.

In a preferred embodiment of the invention, however, the hydrophobic coating is designed so that the water drops do not slide off directly, but remain at least temporarily on the surface. As a result, the individual drops of water can act like a magnifying glass and increase the light transmission.

Of course, superhydrophobic layers with very large contact angles (> 90 degrees) have a higher tendency to roll water droplets than layers with smaller contact angles. Accordingly, the hydrophobic layers are suitable with a contact angle between 50 and 90 Grand, to prevent too easy rolling of the tropics. These can be used especially with inclined glass panes, as are common in the greenhouse area with inclinations of about 20-45 degrees.

In one embodiment of the invention, the insulating glass on one or more antireflection layers, which may theoretically be present on all structurally given glass surfaces of the insulating glass. In one embodiment, an antireflective layer may be attached to the greenhouse glass surface, as previously discussed. However, it may alternatively or additionally be arranged on the outside pane of the insulating glass.

An antireflection layer may in particular be any layer which can reduce the reflection of radiation, in particular radiation having a wavelength of 200 nm to 2500 nm.

An antireflection layer can be used in particular to reduce the refractive index and / or direction-dependent partial reflection at optical interfaces, which are formed during the transition from a medium having a refractive index to another medium having a different refractive index.

In this case, the reflection can be reduced, for example, by structuring the surface and / or by at least one layer whose optical thickness (which results from multiplying the refractive index of the layer by the thickness of the layer) for a specific wavelength equals one quarter of the wavelength , and / or by at least one layer, which contributes to the averaging of the refractive indices of the media which come together at the optical interface.

An antireflection layer may comprise, for example, at least one noble metal layer and / or at least one metal oxide layer and / or at least one fluoride layer, in particular at least one metal fluoride layer, preferably at least one magnesium fluoride layer, which may be sputtered, vapor-deposited or applied by a CVD process (Chemical Vapor Deposition). Method) was applied.

In the context of the present invention, an antireflection layer may also comprise a layer structure comprising a plurality of layers, which may reduce the reflection of radiation, in particular radiation having a wavelength of 200 nm to 2500 nm. Each individual layer may differ, in particular, for example, as a result of the material properties, the refractive index and / or the layer thickness of at least one adjacent layer.

In the context of the present invention, an antireflection layer may preferably be at least one layer which contributes to the structuring of an optical interface or to the averaging of the refractive indices of the media which come together at the optical interface in order to allow a more uniform refractive index transition and thereby the reflection of radiation In particular, to reduce radiation having a wavelength of 200 nm to 2500 nm and at the same time thereby to increase the transmission for radiation, in particular radiation having a wavelength of 200 nm to 2500 nm. An average of the refractive indices of the media, which come together at an optical interface, can thereby contribute to each layer whose refractive index lies between the refractive indices of the media which come together at the optical interface. Preferably, a layer structure of several layers is used, each layer having a different refractive index whose value lies between the refractive indices of the media that come together at the optical interface, so that the transition between the refractive indices of the two media at the optical Boundary surface come together, not directly in one step but through the layers in several steps is made possible to reduce the reflection and at the same time preferably to increase the transmission. A reduction of the reflection, preferably at the same time thereby increased transmission, can be used in particular to increase the solar gain, preferably at substantially the same U-value, since at an increased transmission more radiation, which can contribute to the solar gain, can penetrate through the glazing ,

In a preferred embodiment of the insulating glass according to the invention, the antireflection layer may have a particularly high transmission in the infrared range and in particular a high transmission for radiation in the near infrared range. In this case, the antireflection layer can reduce the reflection of radiation in the infrared range and in particular of radiation in the near infrared range and preferably at the same time thereby increase the transmission for radiation infrared range, in particular of radiation in the near infrared range. The transmission of the insulating glass according to the invention can be increased, for example, by 2%, preferably by 3%, more preferably by 5%, particularly preferably by 6%, in particular in the infrared range and preferably in the near infrared range, for example compared to an insulating glass without antireflection coating. The insulating glass according to the invention can therefore preferably have a high transmission in the infrared range and in particular in the near infrared range. A high transmission may, for example, represent a transmission of at least 60%, preferably at least 70%, more preferably at least 72%, more preferably at least 75%, more preferably at least 80%, and most preferably at least 82%. As a result, the permeability of the insulating glass according to the invention for radiation in the infrared range and in particular for radiation in the near infrared range can be further improved in order to further optimize the solar gain, preferably with substantially the same U value, if appropriate.

Such an antireflection layer, which has a particularly high transmission in the infrared range and in particular a high transmission for radiation in the near infrared range, may comprise for example at least one silicon dioxide layer and / or at least one titanium dioxide layer and / or at least one combination of at least one silicon dioxide layer with at least one titanium dioxide layer include.

In addition, a preferably roughened in the nanometer range surface of a glass sheet as an antireflection layer and in particular anti-reflection layer, which has a particularly high transmission in the infrared range and in particular a high transmission for radiation in the near infrared range, are considered. The surface of a glass pane can be roughened, for example, either mechanically (for example by printing nub-like structures in polymer coatings) and / or chemically (for example by an etching process), preferably in the nanometer range. The size of the structures, which may contribute to the roughness of the surface, may preferably be in the nanometer range and in particular in the range of 1 nm to 100 nm in order to prevent the scattering of radiation, or to reduce it as possible.

In contrast to vapor-deposited, sputtered or CVD-deposited antireflection layers, such antireflection layers can usually have a particularly high transmission in the infrared range and in particular a high transmission for radiation in the near infrared range since they absorb very little radiation in the infrared range and in particular in the near infrared range and / or reflect. As a result, the solar gain can preferably continue to be improved, if at all, for the most part the same U-value.

In a further preferred embodiment of the insulating glass according to the invention, the antireflection layer may be at least one porous layer. If appropriate, the size of the pores can be chosen so that in particular no, or as little as possible, scattering of the radiation occurs. Preferably, this is a pore size in the nanometer range and in particular a pore size from 1 nm to 100 nm. A porous layer (with open or closed porosity or mixture of closed and open porosity) has, due to its porosity and possibly greater roughness compared with a layer that is not porous, a larger surface, so that here the so-called Lotus flower effect (hydrophobing of the surface by creating a micro roughness on the same) can come to fruition.

In addition, depending on the nature of the material, the refractive index of porous antireflection layers may optionally be reduced progressively, for example by a change in porosity, to a particularly low refractive index, which differs only very slightly from the refractive index of the air (which is approximately 1, for example) can. Thus, porous antireflective layers may preferably be used to contribute to averaging the refractive indices of the media that come together at the optical interface and to reduce the reflection of radiation, particularly in the infrared and preferably in the near infrared region, preferably thereby simultaneously transmitting for that radiation is increased.

In a particularly preferred embodiment, the insulating glass according to the invention has at least one porous layer which comprises silicon dioxide. As a result, an antireflection layer can be obtained which has a particularly high transmission in the infrared range and in particular a high transmission for radiation in the near infrared range and is also very resistant and resistant to abrasion. In addition, porous layers comprising silicon dioxide remain largely unchanged even during / after a possible annealing process. An annealing process can even be used for particularly permanent bonding ("burning in") of such a layer to the glass.

In a further preferred embodiment of the insulating glass according to the invention, a porous silicon dioxide layer can be applied by a dipping method or a sol-gel method. The advantage here is that both sides of a pane of glass can be equipped with an antireflection layer at the same time by such a method. In this case, the solar gain can be further improved by two antireflection layers, since the transmission of radiation, which can contribute to the solar gain, can be further increased by a second antireflection coating.

This antireflection layer may in this case be arranged in addition to the possibly present outside hydrophobic layer. In this case, it is expediently positioned below the hydrophobic layer. In an alternative embodiment, the outside hydrophobic layer itself constitutes an antireflection layer.

In one embodiment of the application, the insulating glass additionally has a low-emitting layer which is arranged on the outside of the insulating glass or on a surface of the insulating glass facing the space between the panes (SZR).

In one embodiment of the invention, in the insulating glass, the hydrophobically coated insulating glass pane has a contact angle against water of more than 60 °, preferably of more than 70 ° and especially of more than 80 °.

In a particular embodiment, the contact angle here is at least 130 ° and in particular at least 150 °. Such surfaces are also referred to as "ultrahydrophobic surfaces. Characteristic of such ultrahydrophobic surfaces is still the easy rolling of liquid droplets, which is due to a very low contact angle hysteresis. The contact angle hysteresis is the difference of the advancing contact angle θ _a and the retrogressive contact angle θ _{r of} a liquid drop being discharged onto a surface.

In a preferred embodiment, the insulating glass according to the invention consists of two glass panes, which are each provided on both sides with an antireflection coating, wherein the greenhouse-side antireflection coating is provided with a hydrophilic coating.

In a particularly preferred manner, these two disks are a 4 mm thick low-iron toughened glass.

In one embodiment of the invention, the outside glass is a textured glass or a float glass.

In a special embodiment of the invention, the insulating glass thus seen from the greenhouse interior has the following structure:

Hydrophilised AR layer / low iron glass, 4mm toughened / AR layer / SZR / AR layer / low iron structural glass, 4mm toughened / AR layer

In an alternative specific embodiment of the invention, the insulating glass seen from the greenhouse interior has the following structure:

Hydrophilised AR coating / low iron float glass 4mm toughened / lowE-layer / SZR / AR-layer / low iron float glass 4mm toughened / AR-layer

In another aspect, the invention provides a greenhouse system comprising at least one plant culture and wherein at least a portion of the greenhouse system glass has a hydrophilic coating on the greenhouse side interior of the insulating glass.

In the greenhouse system according to the invention, at least part of the glazing has an insulating glass according to the invention, as has been disclosed in detail above.

definitions

Under an insulating glass according to the invention is according to the in DIN standard EN 1279-1 definition defined a mechanically stable and durable unit of at least two glass panes, which are separated by one or more spacers and hermetically sealed in the edge region. In the closed space between the panes is dried air, nitrogen or a special gas such as argon, krypton or xenon or a mixture of two or more of these gases.

The insulating glass according to the invention in this case comprises all three edge bonding options. Thus, the panes can be edge-welded (so-called all-glass insulating glass), edge-soldered or provided with an organically bonded edge seal. There are glued insulating glass with one and two sealing steps.

Insulating glass with a sealing step consists of a highly active adsorbent (dry matter) filled, perforated spacer frame, which preferably consists of aluminum or galvanized steel. The cavity between the spacer frame and the disc edges is filled with permanently elastic sealant. Predominantly for smaller disc sizes, thermoplastic sealants are also used, e.g. Hot Melt.

In the case of insulating glass with two sealing stages, first the spacer filled with highly active adsorbent (dry matter) is provided with a permanently plastic sealant based on polyisobutylene (butyl). This inner seal serves primarily to seal the space between the panes against penetrating water vapor and gas losses. As a second step, the cavity outside of the spacer frame is additionally filled up to the disc edges with permanently elastic sealant. As the sealant, a suitable silicone or a polysulfide polymer (Thiokol) is preferably used for this purpose.

Another form of insulating glass with 2 sealing steps consists of a so-called thermoplastic spacer, usually butyl-based, with incorporated therein adsorbent material which is extruded as a spacer on one of the panes of the insulating glass. The space between the thermoplastic spacer (which replaces the previously described perforated spacer) and the disc edges is filled with Thiokol or silicone, as in a standard insulating glass.

The "greenhouse-side" surface of the glass pane is that surface which is located on the room side, that is to say located to the interior of the greenhouse.

For the purposes of the invention, the term "chemically resistant" denotes a resistance of the coating to the action of chemicals. This includes both the prevention of corrosion, which is associated with material input, as well as the prevention of the limitation of the material properties, in this case, the hydrophilic or hydrophobic properties of the coating.

Accordingly, according to the invention, the term "mechanically resistant" is defined as a resistance of the coating to abrasion, impact or impact.

According to the invention, the term hydrophilic layer comprises both a separate layer applied to the glass surface and also the glass surface itself insofar as it forms a hydrophilic glass surface by an appropriate treatment (eg etching).

For the purposes of the present invention, the term greenhouse system (which is used synonymously with the term greenhouse) encompasses all types of translucent structures, such as glasshouses, greenhouses, or combinations thereof, which allow the protected cultivation of plants, which preferably comprise at least one plant culture , In this case, the greenhouse system may comprise at least one, but also a plurality of different translucent structures, which are interconnected in some way, for example, through passageways, passageways, tunnels, doors, gates, locks. The individual translucent constructions that allow the protected cultivation of plants, for example, in single construction (each with four exposed walls), in mass production (with at least one common partition between two adjacent constructions) or in block construction (as contiguous blocks with outer walls, but without partitions between adjacent constructions). They can also be designed as an extension to non-permeable buildings.

According to the invention, the light transmittance τ _{v expresses} the directly transmitted visible radiation component in the wavelength range from 380 nm to 780 nm, based on the light sensitivity of the human eye. The light transmission is measured in% and is in accordance with DIN standard EN 410: 2011 determinable.

EXAMPLES

Structure 1:

A double-glazed insulating glass was produced with the following structure: hydrophilized AR layer / low-iron glass biased 4 mm / AR layer / SZR / AR layer / structural glass low-iron prestressed 4 mm / AR layer

The hydrophilization of the AR layer was carried out with the coating solution TA 2201 from Nadico Technologie GmbH, Langenfeld, Germany. This is a sol-gel coating liquid containing TiO ₂ , WO ₃ and SiO ₂ nanoparticles. This solution was applied using the high volume low pressure (HVLP) spray technique. At a processing temperature of 20 ° C it dries out in about 15 minutes. Curing is reached after 72 hours.

The spectral values of the individual slices were measured with a suitable spectrophotometer (for example Lambda-900 from Perkin Elmer).

• • Tau_UV (280–380 nm) 73,3% (nach DIN EN410:2011 )
• • Tau_VIS(380–780 nm): 94,5%(nach DIN EN410:2011)
• • Tau_PAR (400–700 nm): 93,9 (nach NEN 2675 )

Examination of the transmission properties under normal incidence gave the following values:

• • Tau _UV (280-380 nm) 73.3% (acc DIN EN410: 2011 )
• • Tau _VIS (380-780 nm): 94.5% (according to DIN EN410: 2011)
• • Tau _PAR (400-700 nm): 93.9 (after NEN 2675 )

Transmission Hemispheric (measurements by Wageningen University, Netherlands)
Tau _{VIS hem} (380-780 nm): 80.6%
Tau _{PAR hem} (400-700 nm): 80.3

Structure 2:

A double-glazed insulating glass was manufactured with the following construction: Hydrophilized AR coating / Low-iron float glass 4mm toughened / lowE-layer / SZR / AR-layer / Low-iron float glass 4mm toughened / AR-layer

The hydrophilization of the AR layer was carried out as described for construction by TA 2201.

The spectral values of the individual slices were measured with a suitable spectrophotometer (for example Lambda-900 from Perkin Elmer).

Examination of the transmission properties under normal incidence gave the following values:
Tau _UV (280-380 nm) 28.2% (after DIN EN410: 2011 )
Tau _VIS (380-780 nm): 91.2% (according to DIN EN410: 2011)
Tau _PAR (400-700 nm): 89.5 (acc NEN 2675 )

FIGURE LEGENDS

1 : Insulating glass with greenhouse-side hydrophilic layer

2 : Schematic representation of the effect on the light reflection by water droplets on the inside of insulating glass. The refractive index difference between air and water leads to total reflection due to the transition from an optically denser medium to an optically thinner medium (n _{D water} > n _{D air} ) Since the condition for total reflection is as follows: total angular reflection α = arcsin (nAir / nWater) = about 49 degrees.

3 : Effect of a water film on the reflection of light at normal incidence of light

Substantially less light is reflected at the water / air interface at normal light incidence on the interface than at the glass / air transition.

4 : Light scattering effect of drops of water that rest on the outside of a glazing. Due to the transition from a thinner to a denser medium no total reflection takes place here.

5 Modeling of the waterdrop effect by means of polymer-attached glass spheres oriented toward the Ulbricht sphere with detector (A) or pointing away from it (B). The Haze value was determined using the device "Hazaeguard Plus" from BYK Gardner. The difference in the transmission due to the different beam path can be clearly seen (see 1 and 4 ).

LIST OF REFERENCE NUMBERS

1

 Spacer with desiccant

2

 Space between panes of insulating glass (possibly with gas filling)

3

 Inner pane of insulating glass

4

 Outer pane insulating glass

5

 Butyl seal insulating glass

6

 Edge sealing insulating glass (polysulfide, silicone or polyurethane)

7

Hydrophilic coating on ( 3 )

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 2062881 A1 [0027]
• EP 1118646 A1 [0032]
• US 5480917 [0033]
• EP 1944277 A1 [0034]
• EP 2256153 A1 [0034, 0046]
• EP 1477466 A1 [0036]
• US 5208111 [0038]
• EP 1712531 A2 [0040]
• WO 2009/092664 [0041]
• EP 2698246 A1 [0042]
• WO 2007/021180 [0043]
• WO 2011/080472 [0048]
• EP 1923363 A2 [0049]
• WO 2008/104150 [0056]
• DE 10241708 [0057]
• EP 0759413 A1 [0082]
• EP 0661358 A1 [0083]
• DE 10261285 A1 [0084]
• EP 1449642 A1 [0085]
• EP 2116518 A1 [0086]
• EP 1600429 A1 [0087]

Cited non-patent literature

• DIN standard EN 410 [0059]
• DIN standard EN 410 [0063]
• ASTM D 1003 [0069]
• DIN EN 673 [0073]
• DIN standard EN 1279-1 [0119]
• DIN standard EN 410: 2011 [0129]
• DIN EN410: 2011 [0133]
• NEN 2675 [0133]
• DIN EN410: 2011 [0138]
• NEN 2675 [0138]

Claims (20)

Greenhouse insulated glass, consisting of at least two spacers ( 1 ) through an air- or gas-filled gap ( 2 ) separate glass panes, which are hermetically sealed in the edge area ( 5 . 6 ) characterized in that on the greenhouse side surface of the insulating glass, a chemically and mechanically resistant hydrophilic layer ( 7 ) is arranged. Insulating glass according to claim 1, characterized in that the hydrophilic layer ( 7 ) is arranged on a foil which is laminated on the greenhouse side surface of the insulating glass. Insulating glass according to claim 1 or 2, characterized in that the hydrophilic layer ( 7 ) comprises on one of a chemical compound selected from the group consisting of SiO, SiO ₂ , TiO ₂ , WoO, or organic polymers such as polyacrylamide, polyethers such as polyacrylate, polyacylalkyleneimine, polyalkyleneoxide-polycarboxylic acid cross-linked product, polyallyl diglycolcarbonate (CR39, PADS ), Polycarbonate, polycycloolefin, poly (ethylene-old-maleic acid), polyethylene oxide, polyethylene oxide-co-polypropylene oxide block copolymer, polyethersulfone, polyethylene glycol or polyethylene glycol diacrylate, polyhydroxyalkyl acrylates such as (homo) polymers of hydroxyethyl methacrylate (HEMA), Hydroxyethyl acrylate, hydroxypropyl acrylate, polyethylene terephthalate (PET), polyimines, poly (N, N-dialkylacrylamide), polymethyl methacrylate (PMMA), polyols, polyoxazoline, polysorbates, polythiourethane, polyvinyl alcohol, polyvinyl acetal, polyvinyl acetate, poly (vinyl ether), polyvinyl pyrrolidone, polyvinyl pyridine, polyurethane, cross-linked Polyurethane resin obtained by reaction of polyisocyanate at with polyether polyol or polyester polyol, styrene acrylonitrile, triacetyl acetate, and mixtures or copolymers thereof. Insulating glass according to claim 1 to 3, characterized in that the hydrophilic layer ( 7 ) is an antireflection layer. Insulating glass according to one of the preceding claims, characterized in that the insulating glass has a τ _UV value according to DIN standard EN 410 of more than 10%, preferably more than 40% and more preferably more than 60%. Insulating glass according to one of the preceding claims, characterized in that the hydrophilic layer ( 7 ) is produced by etching the glass surface with a fluorine-containing agent such as hydrofluoric acid, H ₂ SiF ₆ or H ₂ TiF ₆ . Insulating glass according to one of the preceding claims, characterized in that the hydrophilic coated surface of the insulating glass has a contact angle against water of less than 40 °, preferably less than 35 ° and especially less than 30 °. Insulating glass according to one of the preceding claims, characterized in that in the air- or gas-filled gap ( 2 ) a polymer film or polymer disc is embedded, which preferably consists of polycarbonate or polyacrylate. Insulating glass according to one of the preceding claims, characterized in that at least one and preferably all the glass panes of the insulating glass have an iron oxide content of less than 0.5 wt .-%. Insulating glass according to one of the preceding claims, characterized in that the glass panes ( 3 . 4 ) have a thickness in the range of 2 to 10 mm, preferably 2 to 6 mm, and more preferably 4 mm. Insulating glass according to one of the preceding claims, characterized in that the insulating glass has a degree of light diffusion according to ASTM D 1003 of more than 20%, preferably more than 40% and particularly preferably more than 60%. Insulating glass according to one of the preceding claims, characterized in that the insulating glass has a U-value according to DIN EN 673 of less than or equal to 3 W / (m ² K), preferably of less than or equal to 1.6 W / (m ² K), particularly preferred of less than or equal to 1.3 W / (m ² K). Insulating glass according to one of the preceding claims, characterized in that the glass panes of a single-pane safety glass (ESG) or a partially prestressed glass (TVG) are. Insulating glass according to one of the preceding claims, characterized in that a hydrophobic layer is arranged on the outside pane surface of the insulating glass. Insulating glass according to one of the preceding claims, characterized in that on the outside pane of the insulating glass, an antireflection layer is arranged, wherein the antireflection layer a) is arranged in addition to an outside hydrophobic layer; or b) itself represents a hydrophobic layer. Insulating glass according to claim 15, characterized in that the hydrophobic layer comprises a chemical compound selected from the group consisting of polysiloxane, perfluoropolyether and other fluoropolymers, polystyrene, polyoxypropylene, polyvinyl acetate, polyoxybutylene, polyisoprene, polybutadiene, polyvinyl chloride, polyalkyl acrylate, polyalkylene methacrylate, polyacyl nitrile , Polypropylene, polyethylene, polytetrahydrofuran (PTHF), polymethacrylates, polyacrylates, polysulfones, polyvinyl ethers, poly (propylene oxide) and copolymers thereof. Insulating glass according to one of claims 15 or 16, characterized in that it additionally comprises a low-emitting layer, which is arranged on the outside of the insulating glass or on a to the space between the panes (SZR) facing surface of the insulating glass. Insulating glass according to one of claims 15 to 17, characterized in that the hydrophobically coated insulating glass pane has a contact angle against water of more than 60 °, preferably of more than 70 ° and especially of more than 80 °. Greenhouse system, characterized in that it comprises at least one crop, wherein at least a portion of the glazing of the greenhouse system on the greenhouse side of the insulating glass has a hydrophilic coating. Greenhouse system according to claim 19, characterized in that at least a part of the glazing comprises an insulating glass according to one of claims 1 to 18.

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