CN115812068A

CN115812068A - Glass pane having a sol-gel coating comprising nanoinlays

Info

Publication number: CN115812068A
Application number: CN202280002272.8A
Authority: CN
Inventors: J·哈根; P·吉拉德
Original assignee: Saint Gobain Glass France SAS
Current assignee: Saint Gobain Glass France SAS
Priority date: 2021-06-29
Filing date: 2022-05-09
Publication date: 2023-03-17
Also published as: EP4363386A1; KR20240025002A; WO2023274610A1

Abstract

The invention relates to a coated glass pane, comprising a transparent substrate (1), a sol-gel coating (2) on the surface of the substrate (1), wherein the sol-gel coating (2) comprises a metal oxide-or semimetal oxide-based sol-gel matrix (3) which is provided with nanoinlays (4), and wherein the nanoinlays (4) comprise a core (4 a) and a shell (4 b) arranged around the core (4 a), and wherein the shell (4 b) is produced by atomic layer deposition.

Description

Glass pane with sol-gel coating comprising nanoinlays

The invention relates to a coated glass pane, a method for the production thereof and the use thereof.

Sol-gel coatings are well known per se. In this case, a solution (sol) with the precursor is applied to the surface of the glass plate, where the precursor condenses into a gel which remains on the surface of the glass plate after the solvent has been drained off. The advantages of sol-gel coatings include low cost and easy wet chemical processing.

Another advantage of sol-gel coatings is that their properties can be adjusted relatively easily, in particular by the choice of precursors and/or by inserts which can be easily added to the sol solution. For example, WO2008059170A2 discloses sol-gel coatings made of silica comprising nano-inserts in the form of pores (produced by thermally decomposed PMMA inserts), silica hollow spheres or oil droplets. By means of the insert, the refractive index of the sol-gel layer can be adjusted (lowered), so that the sol-gel coating can be used as an anti-reflection coating on a glassy glass plate. The subsequently published WO2021209201A1 discloses optically high refractive index sol-gel coatings which in one embodiment are formed from a sol-gel matrix made of silica comprising refractive index increasing inserts, in particular titanium dioxide inserts.

However, the possibilities of adjusting the properties of the sol-gel coating by means of an insert are limited. Therefore, the maximum achievable insert ratio (doping level) is limited.

There is a need for improved sol-gel coatings whose properties can be adjusted over a wide bandwidth range or which can be used to achieve multifunctional coatings. Furthermore, it would be advantageous to improve the mechanical stability and aging behavior of sol-gel coatings.

So-called core-shell nanoparticles are known, which comprise a core and a shell made of different materials. The refractive index of such nanoparticles is essentially due to the so-called quantum confinement effect and can therefore be adjusted over a large bandwidth, in particular by selecting their size. It is also known that shells of core-shell nanoparticles can be produced by atomic layer deposition (ALD, atomic layer deposition). Atomic layer deposition is capable of producing high quality shells with precisely defined layer thicknesses. It has been demonstrated in the literature, for example, that the chemical resistance of nanoparticles can be improved by such ALD shells (a.w. Weimer,Particle atomic layer depositionjournal of Nanoparticle Research 21, 2019). It has also been demonstrated that the mechanical stability of nanoparticles can be improved, their hardness and their elastic modulus can be varied, and their refractive index can be tuned by selecting the size of the core and the layer thickness of the shell (l. Zhang et al,Mechanical properties of atomic layer deposition-reinforced nanoparticle thin filmsnanoscale, 9 months 2012).

WO2015075229A1 discloses porous anti-reflective coatings comprising organic-inorganic hybrid core-shell nanoparticles, which are manufactured by a wet chemical process. WO2011157820A1 and WO2013174754A2 also disclose sol-gel coatings comprising inserts made of wet-chemically fabricated core-shell nanoparticles.

It is an object of the present invention to provide a glass sheet with an improved sol-gel coating. The properties of sol-gel coatings, in particular their refractive index, should be adjustable precisely and reproducibly over a large bandwidth. The coating should also have mechanical stability and resistance to ageing and be suitable as a multifunctional coating.

According to the invention, the object of the invention is achieved by a coated glass sheet and a method for manufacturing the same according to the independent claims. Preferred embodiments follow from the dependent claims.

The coated glass sheet of the present invention comprises at least one transparent substrate and a sol-gel coating on the surface of the substrate. The sol-gel coating comprises or consists of a sol-gel matrix or a matrix formed according to the sol-gel principle (sol-gel matrix), which is provided with nano-inserts. The nanoinlays may also be referred to as dopants of the sol-gel matrix. According to the invention, the sol-gel matrix is formed on the basis of or consists of a metal oxide or semimetal oxide. The semimetal oxide may also be referred to as a semiconductor oxide. In addition to the metal oxide or semimetal oxide, the sol-gel matrix may contain process-related residues or additives, such as stabilizers or uv blockers. The intercalates are incorporated into the sol-gel matrix, in particular by adding them (preferably as a solution) to the sol, so that they are surrounded by the sol-gel matrix during condensation and drying of the sol-gel coating.

If the component is formed on the basis of a material, the component consists essentially of this material, in particular essentially of this material, apart from possible impurities or dopants. The proportion of this material is greater than 50% by weight, preferably greater than 70% by weight, very particularly preferably greater than 90% by weight. This proportion is in particular greater than 99% by weight, based on the metal oxide or semimetal oxide as nanoinlay (shell or core) material.

According to the invention, the nanoinlay comprises a core and a shell arranged around and surrounding the core. The core and the shell are made of different materials. Thus, nanoinlays may be understood as core-shell nanoparticles. According to the invention, the shell is produced by atomic layer deposition (atomic layer deposition, ALD) on the core.

The sol-gel coating can be produced cost-effectively. They are applied to the substrate in a wet-chemical manner without complications, either over the entire surface or only in subregions. They can be used in a variety of ways and their properties can be well controlled, for example by selecting the materials of the sol-gel matrix and/or possible inserts). This case is utilized within the scope of the invention by a nanoinlay according to the invention, which comprises a shell produced by atomic layer deposition. For example, the nano-inserts may affect the optical properties of the coating and/or increase its chemical or mechanical stability. Better embedding into the matrix or better bonding to the matrix can be achieved by the shell. By means of the nanoinlays, in particular, a very flexible adjustment of the refractive index over a large range can be achieved, since the refractive index of the nanoinlays is due to quantum effects ("quantum confinement"). These quantum effects result from electronic interactions between the shell and the core, and are influenced by the choice of materials and dimensions of the core and the shell. Atomic layer deposition enables the production of shells with a very precisely defined layer thickness, so that the properties can be adjusted precisely and reproducibly. Furthermore, atomic layer deposition produces very dense layers, on the one hand ensuring high chemical and mechanical stability and on the other hand resulting in the desired properties also having been achieved at relatively small layer thicknesses. By controlling the thickness, chemical composition and density of the shell almost perfectly, optical effects based on "quantum confinement" effects can be achieved, for example, which are not possible in less precise deposition methods. Furthermore, atomic layer deposition is useful for many materials and well studied, especially for many oxides and nitrides, so the invention can be flexibly used for a large number of applications. This is a great advantage of the present invention.

As can be seen from the nanoinlays, the shell is produced by atomic layer deposition, for example by high resolution transmission electron microscopy (HRTEM, high resolution transmission electron microscopy). Atomic layer deposition leads to an ideally uniform formation of the shell, which achieves an almost perfectly constant layer thickness of the shell, even at the atomic level, which is not achieved by other coating methods. The shell follows the contour of the core surface almost perfectly and is ideally formed concentrically therewith, for example in the case of a spherical core.

The thickness of the sol-gel coating is preferably from 30 nm to 500 nm, particularly preferably from 50 nm to 150 nm.

In an advantageous embodiment, the sol-gel matrix is based on Silica (SiO) ₂ ) Or from SiO ₂ And (4) forming. SiO 2 ₂ Sol-gel coatings are well studied and can be produced with high quality. Furthermore, siO ₂ Having a refractive index similar to that of typical substrates, in particular soda-lime glass plates or plastic glass plates made of PMMA or polycarbonate. Thus, siO ₂ The sol-gel coating is optically compatible with such substrates. By means of such a coating, antireflection properties can also be produced, in particular by means of a specifically adjusted porosity or other refractive index-reducing inserts. However, other sol-gel matrices, e.g. based on TiO, may also be used ₂ To produce an optically high refractive index layer.

Nanoinlays are core-shell nanoparticles in which a shell ("shell") is created on a core ("core") by atomic layer deposition. Alternatively, the nano-inserts may be hollow particles formed by a shell surrounding a cavity (hole) forming the core. For this purpose, the polymer nanoparticles can be provided with a shell by atomic layer deposition, the coated nanoparticles being embedded in a coating and the polymer core then being removed thermally or by means of a solvent. Nanoinlays or nanoparticles are understood as meaning particles having a size in the nanometer range, i.e. from 1 nm to less than 1000 nm (1 μm). The nano-inserts or nano-particles are preferably formed in a spherical shape, i.e. with a substantially circular cross-section. Alternatively, the nano-inserts or nanoparticles may also have other cross-sections, such as an elliptical, oval or elongated cross-section (elliptical or oval nanoparticles).

The proportion by volume of nanoinlays (total volume of all nanoinlays divided by total volume of sol-gel coating) in the sol-gel coating is preferably 10% to 90%, particularly preferably less than 80%, very particularly preferably less than 70% or less than 60%.

Depending on the intended use in the application, the nanoinlays may be formed in different ways or methods-this applies to the core and shell materials and combinations thereof. Both the core and the shell are preferably formed of a dielectric material. Dielectric materials in the sense of the present invention have in particular less than 10 ^-4 Conductivity (reciprocal of resistivity) of S/m.

In a preferred embodiment, the core is designed as a pore, i.e. as a (in particular gas, air or vacuum filled) void in the sol-gel matrix. Through the pores, the refractive index of the sol-gel coating can be adjusted, in particular lowered compared to the refractive index of the sol-gel matrix. The coating can thus be provided with anti-reflection (anti-reflection) properties.

In the context of the present invention, the refractive index is in principle given with respect to a wavelength of 550 nm. The refractive index may be determined, for example, by ellipsometry. Ellipsometers are commercially available, for example from Sentech corporation.

In another preferred embodiment, the core is formed from or consists of a polymer or polymer-based. By means of an insert comprising such a core, the refractive index of the coating can likewise be adjusted. In addition, the stability and mechanical properties of the coating can sometimes be improved. Polymethyl methacrylate (PMMA) is particularly preferred because of its suitable refractive index, good availability and operability. Alternatively, for example, polycarbonate, polyester, polystyrene or copolymers made from methyl (meth) acrylate and (meth) acrylic acid may also be used.

The polymer core may also act as a precursor for the pores if the core thermally decomposes or is dissolved out by a solvent during temperature treatment after embedding in the sol-gel matrix. Besides PMMA, for example polycarbonate, polyester, polystyrene or copolymers made from methyl (meth) acrylate and (meth) acrylic acid are also suitable for this purpose.

In another preferred embodiment, the core is formed from or based on a metal oxide or semimetal oxide or consists of a metal oxide or semimetal oxide. Particularly preferred is silicon oxide (SiO) ₂ ). Thus, for example, the refractive index of the coating can also be adjusted, wherein the sol-gel matrix is also made of SiO ₂ Formation, the effect is mainly due to the shell and through SiO ₂ The core ensures good optical compatibility with the matrix. Particular preference is also given to titanium oxide (TiO) ₂ ) Alumina (Al) ₂ O ₃ ) Zirconium oxide (ZrO) ₂ ) Or hafnium oxide (HfO) ₂ ). The refractive index of the coating can also be adjusted thereby if the sol-gel matrix consists of SiO ₂ The refractive index is formed, in particular increased. Furthermore, by TiO ₂ The coating may be provided with photocatalytic, self-cleaning properties.

In a further preferred embodiment, the core is formed as a hollow particle, i.e. as a shell around a (in particular air-filled) cavity. The hollow particles being formed from or based on metal oxides or semimetal oxides, e.g. SiO ₂ Or TiO ₂ And (4) forming. In particular, siO ₂ Hollow particles are commercially available and can be easily purchased. Pores are formed in the sol-gel matrix via the cavities, whereby the refractive index thereof can in turn be adjusted, wherein SiO ₂ The coating ensures good optical compatibility with the sol-gel matrix, at least if it is also made of SiO ₂ And (4) forming. However, the hollow particle core can also be used for other purposes, for example for producing scattering surfaces on a substrate, which are used, for example, for light outcoupling.

Particularly preferably, the core is a pore, made of a metal oxide or semimetal oxide (in particular SiO) ₂ And TiO ₂ ) Or as a mixture of metal oxides or semimetal oxides, in particular SiO ₂ And TiO ₂ ) The resulting hollow particles are formed. A very particularly preferred core material is SiO ₂ A hole and SiO ₂ Hollow particles, since they have a wide range of application possibilities.

The size of the core is preferably from 10 nm to 500 nm, particularly preferably from 10 nm to 150 nm, very particularly preferably from 50 nm to 100 nm. Good results can thereby be obtained, in particular with regard to embedding the nanoparticles in the sol-gel matrix and adjusting the refractive index thereof. Size is understood here to mean the largest dimension of the core that occurs along the spatial dimension, i.e. its diameter in the case of spherical nanoparticles. The size of at least 80% of all the cores is preferably within the indicated range, with all the cores being particularly preferred.

The shell of the nanoinlay preferably has a refractive index of more than 1.5, particularly preferably more than 1.7, in particular more than 1.9. This is particularly advantageous if an increase in the refractive index of the sol-gel matrix should be achieved by means of the nanoinlays. But even if this is not the case, a slight increase in the refractive index due to the shell material is acceptable, for example if a significant improvement in the mechanical properties can be achieved thereby.

In a preferred embodiment, the shell is formed from or based on or consists of a metal oxide or semimetal oxide. Suitable metal oxides or semimetal oxides are, for example, silicon oxide (SiO) ₂ ) Alumina (Al) ₂ O ₃ ) Or transition metal oxides, especially titanium oxide (TiO) ₂ ) Zirconium oxide (ZrO) ₂ ) Or hafnium oxide (HfO) ₂ ). If the sol-gel matrix consists of SiO ₂ Can be formed by SiO ₂ The shell achieves good bonding of the nanoinlays to the matrix. Other metal oxides mentioned may, for example, lead to an increase in the refractive index, for example in order to equip the coating with reflective properties. By TiO ₂ The shell can also be provided with photocatalysis and self-cleaning performance for the coating. It is particularly preferred thatFrom SiO ₂ Or TiO ₂ And (4) preparing a shell.

The shell may alternatively be formed of or based on nitride, depending on the application. An example is silicon nitride (Si) ₃ N ₄ ) Or aluminum nitride (AlN). This may be of particular advantage for the application in terms of e.g. the surface properties of the nano-inserts and/or the binding of the shell to the core. The choice of the shell material is of course made under a pre-regulation that it must be different from the core material.

Even if a stoichiometric molecular overall formula is given for a better understanding, the oxides and nitrides used in the context of the present invention do not necessarily have to be formed stoichiometrically, but may instead also be sub-or superstoichiometrically. The same applies to the core and shell of the nanoinlays and to the sol-gel matrix. However, the shells of the nanoinlays are preferably formed in stoichiometric amounts, which can be done accurately and reproducibly by depositing a complete monolayer in an atomic layer deposition process.

The shell preferably has a layer thickness of 1 nm to 100 nm, particularly preferably 2 nm to 20 nm, in particular 5 nm to 15 nm. Such thin shells can be easily manufactured by atomic layer deposition and are sufficient to yield the required properties due to the high density achieved by atomic layer deposition. In the sense of the present invention, unless otherwise specified, layer thickness refers to the geometric thickness of the layer, and not, for example, the optical thickness, which is given as the product of the geometric thickness and the refractive index.

The sol-gel coating according to the invention can be used in a wide range of applications and performs a wide range of functions here. The sol-gel coating may be, for example:

-an anti-reflective coating: this is in particular a coating with a lower refractive index than the substrate. In particular, they may be prepared by SiO ₂ A matrix is formed, the SiO is ₂ The refractive index of the matrix is controlled by the pores (which act as cores or hollow particles of the nanoinserts, in particular SiO) ₂ Hollow particles as the core of the nano-insert). The refractive index depends on the pore size and pore density. The proportion of the pore volume in the total volume is preferably from 10 to 90%, particularly preferably less than 80%, very particularly preferably less than60％。SiO ₂ Particularly preferred as shell to optimize the pores or hollow particles with SiO ₂ And (4) combining the matrixes. However, all the other materials mentioned can also be envisaged for the shell, in particular if the coating should be provided with other properties.

-a reflectivity-increasing coating: this is in particular a coating with a higher refractive index than the substrate. They can be obtained, for example, by using sol-gel matrices (in particular TiO) having a high refractive index ₂ 、ZrO ₂ Or HfO ₂ ) Or by SiO containing nano-inserts of increasing refractive index ₂ Substrate (especially TiO) ₂ 、ZrO ₂ Or HfO ₂ As a shell or core of a nano-insert).

Hydrophilic or hydrophobic coatings, i.e. coatings that influence the use behavior of the substrate surface.

A sunscreen coating, i.e. a coating that reflects or absorbs electromagnetic radiation in the infrared and/or ultraviolet range.

-photocatalytic coating: such coatings are suitable for decomposing organic deposits and thus have self-cleaning properties. Photocatalytic properties, in particular by using TiO ₂ As a sol-gel matrix or as a material for the shell or core of the nanoinlay.

-a light scattering coating: the coated areas of the substrate surface are thus equipped with strong light scattering properties. This can be used, for example, for coupling out light coupled into the substrate via the side edges and propagating therein by total reflection from the substrate for illumination purposes or for producing a display.

-a decorative coating, in particular a coloured coating. For example, the reflected color can be tuned by the refractive index of the sol-gel coating and possible optical interference effects.

Due to the high flexibility of the coating design (the materials of the sol-gel matrix and the shell and core of the nano-insert can be chosen independently of each other), multifunctional coatings can be achieved, especially those fulfilling several of the above functions. Examples of this are:

anti-reflective coatings with photocatalytic properties

Anti-reflective coatings with hydrophobic properties

Photocatalytic coating with hydrophobic properties

Anti-reflective coatings with a sunscreen effect

-a colored anti-reflective coating.

The preferred materials mentioned above for the core and the shell of the nanoinlay can in principle be combined with one another at will. Particularly preferred combinations are, for example:

-a nucleus: hole, shell: siO 2 ₂ : such nano-inserts can be used to reduce the refractive index of the sol-gel coating. They can also increase mechanical and chemical resistance and reduce fingerprint visibility. In SiO ₂ In the case of a matrix, siO ₂ The shell improves the bonding of the insert to the matrix. They can be produced in particular by the inclusion of a polymer core (preferably a PMMA core) and SiO ₂ Nanoparticles of a shell are produced, wherein the core is thermally decomposed or dissolved out after coating.

-a nucleus: hole, shell: tiO 2 ₂ : such nano-inserts may also be used to reduce the refractive index of the sol-gel coating, wherein the shell also imparts photocatalytic properties to the coating. A sunscreen coating may also be realized therewith. They can be produced in particular by the inclusion of a polymer core, preferably a PMMA core, and TiO ₂ Nanoparticles of a shell are produced, wherein the core is thermally decomposed or dissolved out after coating.

-a nucleus: siO 2 ₂ Shell, shell: tiO 2 ₂ : such nano-inserts can be used, for example, for reflectivity enhancing coatings, particularly where the refractive index is through TiO ₂ Shell enhanced SiO ₂ In the case of a substrate.

-a core: tiO 2 ₂ Shell, shell: siO 2 ₂ : such nano-inserts may be used, for example, for reflectivity increasing coatings. In SiO ₂ In the case of a substrate, siO ₂ The shell improves binding to the matrix.

-a nucleus: siO 2 ₂ Hollow particles, shell: tiO 2 ₂ : such nanoinlays can be used, for example, for light scattering coatings.

The sol-gel coating may be disposed over the entire surface of the substrate surface. However, the sol-gel coating may also be arranged only on one or more regions of the surface, while other regions are uncoated. For example, the coating may be applied over the entire surface except for the uncoated, surrounding edge regions, so that the central see-through region of the substrate is completely covered by the coating. In this case, in particular at least 80% of the surface of the substrate is provided with a coating. It is particularly advantageous if the coating should provide the substrate with substantially uniform properties as a whole, for example as an anti-reflective coating, a hydrophilic or hydrophobic coating, a sun protection coating and/or a self-cleaning coating. However, it is also possible to provide only locally limited areas with a coating (for example, areas which should be provided with cameras or sensors of a specific nature) or to apply the coating in the form of a pattern on the substrate. Wet-chemical sol-gel processes enable complete and partial coating in a simple manner.

In a preferred embodiment, the substrate is formed as a glass or plastic glass plate. Glass plate here means a substantially rigid, at most elastically bendable plate-like or layer-like object. In the case of vitreous glass sheets, the substrate is preferably made of soda lime glass, as is common for window glass sheets. However, other glass types are also conceivable, such as borosilicate glass, quartz glass or aluminosilicate glass. In the case of plastic glass plates, the substrate is preferably formed from or based on PMMA or Polycarbonate (PC). The thickness of the substrate can be freely chosen depending on the application. Typical thicknesses of glass sheets in the building or vehicle field are, for example, from 0.5 mm to 5 mm, preferably from 1.0 mm to 2.5 mm.

According to the invention, the substrate is transparent. This is understood to mean a see-through substrate which can also be used, in particular, as a window pane. The substrate may be fully tinted or colored, as is common particularly with many vehicle glazing panels. The light transmission of the substrate in the visible spectral range from 400 nm to 800 nm is preferably at least 10%, particularly preferably at least 30%, very particularly at least 50%, in particular at least 70%. These values are based on the total proportion of transmitted radiation in the entire radiation impinging on the substrate in the spectral range shown at an angle of incidence of 0 ° with respect to the surface normal.

The coated glass pane is preferably provided as a window pane, in particular in a building, an interior space or a vehicle.

The invention also comprises a method of manufacturing a coated glass sheet according to the invention, wherein at least:

(a) The provision of nanoparticles of the type described above,

(b) The nanoparticles are provided with a shell by atomic layer deposition,

(c) Providing a sol comprising a metal oxide or semi-metal oxide precursor,

(d) The nanoparticles comprising the shell are added to the sol,

(e) The sol is applied to the surface of the substrate together with nanoparticles comprising a shell,

(f) Condensing the sol into a sol-gel coating, wherein a sol-gel matrix is formed from metal oxide or semimetal oxide precursors, the matrix being provided with a nanoinlay comprising a core formed from nanoparticles and a shell arranged around the core.

These method steps do not necessarily have to be carried out in the order shown, if not technically necessary. The nanoparticles must therefore be provided with a shell (method step b) and then added to the sol (method step d). Nanoparticles provided with a shell must likewise be added to the sol (process step d) and then applied to the substrate surface (process step e). The sol must also be applied to the substrate surface (process step e) and then allowed to condense into a sol-gel coating (process step f). However, it does not matter whether the nanoparticles are first provided with a shell (method step b) and then the precursor is added to the sol (method step c) or vice versa.

Nanoparticles provided with a shell are generally stable for a long time and can therefore be stored, so that the coating of the nanoparticles (process step b) does not have to be carried out directly before the sol preparation (process step c). For example, larger quantities of coated nanoparticles can be prepared for storage and used in sol-gel coatings as needed.

According to the invention, the nanoparticles are provided with a shell by atomic layer deposition. Atomic layer deposition (atomic layer deposition, ALD) is an effective method for depositing thin layers to deposit atomic monolayers. The components (atoms) of the material to be deposited are chemically combined with the carrier gas (so-called precursors or reactants). The components are alternately introduced into the reaction chamber, where they react with the objects to be coated, respectively. Thereby, the respective precursor is chemically bonded to the surface to be coated. The reaction chamber is then emptied and filled with the next precursor. Thereby, alternating sub-layers of coating composition are applied successively. For the production of ALD coatings from metal oxides, suitable reactants are, for example, the corresponding methyl-metal compounds or the corresponding metal chlorides on the one hand and water vapor on the other hand. Methyl-metal compounds (or metal chlorides) are used as the metal source and water vapor is used as the oxygen source. During the reaction of the methyl-metal compound, some of the methyl groups are cleaved off, and the metal comprising the remaining methyl groups is chemically bound to the base sublayer, for example via free OH groups on the surface of the object to be coated or of the layer deposited from water vapor located thereunder. The reaction chamber is then filled with water vapor. During the subsequent reaction, the OH groups replace the methyl groups of the underlying metal sublayer. Subsequently, a next metal sublayer is deposited, which bonds with the OH groups of the preceding deposition step with elimination of methane. This therefore results in an oxygen sublayer between the two metal sublayers. The alternating process is carried out so long until the desired layer thickness is achieved. Between each deposition step, the reaction chamber may be purged with an inert gas, such as argon. One characteristic of ALD is the self-limiting nature of the sub-reactions: the reactants do not react with themselves or their ligands, which limits the growth of the sub-reacted layer to at most one single sublayer for an arbitrarily long time and with gas quantities. In this way, very dense layers with precisely adjusted layer thicknesses can be produced. Due to the uniform distribution of the gas in the reaction chamber, the object is completely covered, apart from possible bearing surfaces, regardless of its geometry. ALD coatings made of semimetal oxides can also be produced, wherein the metal is replaced by semimetal in the above description.

The atomic layer deposition of the shell on the core usually appears to be carried out in portions (batch process), and not for example by a continuous process. A specific amount of nanoparticles is introduced here into the reaction vessel, where it is simultaneously coated with the shell and subsequently removed. Such reactions are usually carried out in so-called "batch reactors".

The nanoparticles are preferably selected or chemically functionalized by surface groups so that they are soluble in the solvent. The solvent can preferably be water, alcohol or a water-alcohol mixture. For the batch process, nanoparticles are provided dissolved in a solvent. The solvent was then evaporated. The nanoparticles are then provided with a shell by atomic layer deposition and then re-dissolved in a solvent, wherein this may be the same solvent as the solvent in which the nanoparticles are provided. Of course, the shell must also be selected or chemically functionalized after atomic layer deposition, so that it ensures the solubility of the coated nanoparticles. The solution containing the nanoparticles can then be added to the sol (method step d).

A sol is a solution containing precursors of a sol-gel matrix dissolved in a solvent. This is in accordance with the invention a metal oxide precursor or a semimetal oxide precursor from which a metal oxide or semimetal oxide matrix can be formed. The metal oxide precursor may be present, for example, as an organometallic compound, as a metal alkoxide, or as a metal carboxylate. As semimetal oxide precursors, similar compounds can be used, in which the metal is replaced by a semimetal. In a preferred embodiment, the metal or semimetal (for example metal alkoxides or metal carboxylates) is stabilized here by ligands in the form of chemical complexes, whereby the reactivity can be reduced and the resistance of the sol to atmospheric moisture can be improved. 2, 4-diketones are, for example, common ligands. The solvent is preferably water, an alcohol (in particular ethanol) or a water-alcohol mixture.

In addition to the precursor and the solvent, the sol may contain a thickener, such as a cellulose derivative (e.g., methylcellulose or ethylcellulose) or polyacrylic acid, to adjust the viscosity of the sol. It is possible for the solvent or thickener to also act as a complexing agent for the metal oxide or semimetal oxide precursor if it is chosen appropriately. In this case, no additional ligands have to be added on purpose. The sol may also comprise typical additives as are commonly used in the sol-gel art and known to the person skilled in the art.

If the substrate is to be made of or based on SiO ₂ The sol is generated and contained in the solventThe silicon oxide precursor of (1). The precursor is preferably a silane, in particular tetraethoxysilane or Methyltriethoxysilane (MTEOS). Alternatively, however, silicates may also be used as precursors, in particular sodium, lithium or potassium silicates, for example tetramethyl orthosilicate, tetraethyl orthosilicate (TEOS), tetraisopropyl orthosilicate or the general formula R ² _n Si(OR ¹ ) _4-n An organosilane of (2). Herein, R is ¹ Preferably an alkyl group, R ² Is an alkyl group, an epoxy group, an acrylate, a methacrylate, an amine, a phenyl group or a vinyl group, and n is an integer of 0 to 2. Silicon halides or silicon alkoxides may also be used.

The precursor may optionally have been aged in solution. Ripening may comprise hydrolysis of the precursors and/or partial formation of aggregates by (partial) reactions between the precursors, in particular polycondensation.

The precursor concentration in the sol is preferably from 0.1 to 20% by weight, particularly preferably from 2 to 10% by weight.

The coated nanoparticles are added to the sol. This is understood to mean that the nanoparticles and the sol-gel precursor are mixed in a solvent. Typically, a solution of the coated nanoparticles is mixed with a sol. However, it is also conceivable in principle to add the precursor directly to the solution of the nanoparticles, i.e. to generate the sol directly therefrom. In this case, the provision of the sol and the addition of the nanoparticles will be effected in one step.

The sol is then applied to the surface of the substrate together with the coated, i.e. shell-equipped, nanoparticles dissolved therein, in particular by wet-chemical methods, for example by dip-coating (dip-coating), spin-coating (spin-coating), flow-coating (flow-coating), by application by means of a roller or brush, by spray-coating (spray-coating) or by printing methods, for example pad printing (pad printing) or screen printing (screen printing). Drying may then be carried out, in which the solvent is evaporated. This drying can be carried out at ambient temperature or by separate heating, for example at temperatures up to 120 ℃. Prior to applying the coating to the substrate, the surface is usually cleaned by methods known per se.

The sol is then condensed into a sol-gel coating according to the invention. This is preferably done by temperature treatment, preferably at a temperature of at least 400 ℃. This can be done as a separate temperature treatment. If the substrate is a vitreous glass sheet to be bent, as is common in the vehicle art, the temperature treatment may be carried out during the glass bending process, typically at a temperature of 600 ℃ to 700 ℃. If the precursor has a UV-crosslinkable functional group (e.g., a methacrylate group, a vinyl group, or an acrylate group), condensation may also include a UV treatment instead of or in addition to a temperature treatment. Alternatively, in the case of suitable precursors (e.g. silicates), the condensation may include IR treatment.

Prior to the actual condensation, a preliminary drying can optionally be carried out, wherein the solvent evaporates and the concentration of the precursor is thereby obtained. This drying can be carried out at ambient temperature or by separate heating, for example at temperatures up to 120 ℃.

During the condensation process, the sol-gel matrix is formed from metal oxide or semimetal precursors. Here, a cross-linking process usually takes place between the precursors, wherein the precursors first combine into aggregates (aggregation, usually by hydrolysis of the precursors and polycondensation between them), and then they cross-link into gels (gelation). Aggregation may also already occur partly in solution, which is then applied to the surface of the glass sheet (curing). The sol-gel matrix is provided with a nanoinlay comprising a core formed by nanoparticles and a shell arranged around the core.

In method step (f), the core of the nanoinlay according to the invention is formed by a nanoparticle. This does not necessarily mean a chemical or mechanical conversion, wherein such a conversion is optionally possible, as is evident from the two preferred embodiments described below.

In one embodiment of the method, the nanoparticles remain in the sol-gel coating after they are created as the core of the nano-intercalator. The nanoparticles of the sol thus form the core of the insert of the sol-gel coating without any transformation. The nanoparticles can here preferably consist of or be based on polymers (for example polycarbonate, polyester or polystyrene, or methyl (meth) acrylate and (meth) acrylic acidPreferably PMMA), from or on metal oxides or semimetal oxides (preferably SiO) ₂ Or TiO ₂ ) Formed of, or based on, metal oxides or semimetal oxides, preferably SiO ₂ ) The resulting hollow particles are formed. The statements made above with respect to the core of the nanoinlay apply correspondingly to the nanoparticles, which are identical in this embodiment.

In an alternative embodiment of the method, the nanoparticles of the sol are precursors of the core of the nano-intercalator. This is especially true when the core of the nano-insert should be a pore. In this case, the nanoparticles act as porogens and are preferably formed from or based on a polymer, for example from or based on PMMA, polycarbonate, polyester or polystyrene or a copolymer of methyl (meth) acrylate and (meth) acrylic acid, with PMMA being particularly preferred. After deposition of the sol-gel coating, the nanoparticles decompose, creating pores as the core of the nano-inserts. The shell of the nanoparticle remains around the pores as a shell. The nanoparticles are decomposed, preferably by means of heat, by treatment at a temperature of at least 400 c, preferably at least 500 c. The polymer nanoparticles are in particular charred (carbonized) here. For this purpose, a separate tempering step can be provided, which is provided after the condensation of the sol-gel matrix. However, alternatively and preferably, the condensation of the sol-gel matrix and the thermal decomposition of the nanoparticles may be carried out during the same temperature treatment, which for this purpose is preferably carried out at least 500 ℃. This can also be done during the glass bending process.

Instead of the thermal decomposition of the polymer nanoparticles, they can also be dissolved out of the coating by means of a solvent. For this purpose, the corresponding polymers must be soluble in solvents, for example Tetrahydrofuran (THF) can be used in the case of PMMA nanoparticles.

The substrate comprising the sol-gel coating according to the invention can be supplied as such to its final intended destination. However, the coated glass sheet must first be subjected to a thermal prestressing and/or bending process. The coated glass sheet may be laminated (flat or curved) with other glass sheets via a thermoplastic interlayer, such as a PVB film, to a composite glass sheet. The coated glass sheet can also be joined with one or more other glass sheets via spacers into an insulating glass unit.

The invention also comprises the use of the coated glass sheet according to the invention in buildings or land-air vehicles. The glass plate is preferably used here for

As window panes, glass doors or facade elements in the outer region of a building,

window, glass door or separating glass panels as rooms in the interior region of a building, or

As a vehicle glazing (for example as a roof glazing, side glazing, rear glazing or windscreen for a vehicle, in particular a motor vehicle)

Or as a component thereof, for example as a component of a composite glass pane or insulating glass unit.

The invention is explained in more detail below with reference to the figures and examples. The figures are schematic and not to scale. The drawings are not intended to limit the invention in any way.

In which is shown:

figure 1 is a cross-section through one embodiment of a coated glass sheet according to the invention,

fig. 2 is a cross-section of a nano-insert through the glass sheet of fig. 1.

Figure 1 shows a cross section through one embodiment of a coated glass sheet according to the invention. It comprises a substrate 1 having a sol-gel coating 2. The substrate 1 is, for example, a 2.1 mm thick glass plate made of soda-lime glass, which is provided as a vehicle glass plate (for example as a component of a laminated windshield plate). The substrate 1 can here form, for example, an inner pane of a windshield and be joined via a PVB film via the surface opposite the sol-gel coating 2 to an outer pane, which is, for example, also a soda-lime glass pane of 2.1 mm thickness.

The sol-gel coating 2 comprises a sol-gel matrix 3, for example made of SiO ₂ And (4) preparing. The sol-gel matrix 3 is produced using a sol-gel process. The sol-gel matrix 3 contains nanoinlays 4, by means of which nanoinlays there may beThe properties of the sol-gel coating 2 are adjusted in a targeted manner.

Fig. 2 schematically shows a cross section through a nano-insert 4. It comprises a spherical core 4a surrounded by a shell 4 b. The shell 4b is produced by atomic layer deposition. For example, the diameter of the core 4a is about 70 nm and the layer thickness of the shell 4b is about 10 nm.

The core 4a and the shell 4b are selected according to the intended application to provide the sol-gel coating 2 with the desired properties. For example, the core may be made of SiO ₂ Consisting of TiO and a shell ₂ And (4) forming. By SiO ₂ Core, nanoinlay 4 optically coupled to SiO ₂ The matrix is well compatible. By TiO ₂ The shell, on the one hand, increases the refractive index of the sol-gel coating 2 and, on the other hand, provides it with photocatalytic properties.

Alternatively, the core 4a may be formed, for example, as a cavity (hole), and the shell 4b is made of SiO ₂ And (4) forming. Through holes, siO ₂ The refractive index of the matrix is lowered and the sol-gel coating 2 can thus be used as an anti-reflective coating. These pores are preferably produced by adding PMMA nanoparticles comprising a shell 4b produced by atomic layer deposition to a sol in the case of a sol-gel coating and allowing these PMMA nanoparticles to thermally decompose after coating, thereby forming pores as the core 4a. From TiO ₂ The shell is made to impart additional photocatalytic properties to the antireflective coating.

List of reference numerals:

(1) Substrate

(2) Sol-gel coating

(3) Sol-gel matrix of sol-gel coating 2

(4) Nanoadders for sol-gel coatings 2

(4a) Core of nanoinlay 4

(4b) A shell of nano-inserts 4.

Claims

1. A coated glass sheet comprising

-a transparent substrate (1),

-a sol-gel coating (2) on the surface of a substrate (1),

wherein the sol-gel coating (2) comprises a sol-gel matrix (3) based on metal oxides or semimetal oxides, which is provided with a nanoinlay (4),

and wherein the nanoinlay (4) comprises a core (4 a) and a shell (4 b) arranged around the core (4 a),

and wherein the shell (4 b) is produced by atomic layer deposition.

2. The coated glass pane of claim 1, wherein the sol-gel matrix (3) is based on Silica (SiO) ₂ ) And (4) forming.

3. Coated glass pane according to claim 1 or 2, wherein the shell (4 b) has a refractive index of more than 1.5, preferably more than 1.7, particularly preferably more than 1.9.

4. Coated glass pane according to any one of claims 1 to 3, wherein the shell (4 b) is based on a metal oxide or a semimetal oxide, preferably on silicon oxide (SiO) ₂ ) Alumina (Al) ₂ O ₃ ) Or transition metal oxides, especially titanium oxide (TiO) ₂ ) Zirconium oxide (ZrO) ₂ ) Or hafnium oxide (HfO) ₂ ) And (4) forming.

5. The coated glass pane according to any one of claims 1 to 4, wherein the shell (4 b) has a layer thickness of 1 nm to 100 nm, preferably 2 nm to 20 nm, particularly preferably 5 nm to 15 nm.

6. Coated glass sheet according to any of claims 1 to 5, wherein the core (4 a)

As a hole, a hole is formed,

based on polymers, preferably polymethyl methacrylate (PMMA)

Based on metal oxides or semimetal oxides, preferably silicon oxide (SiO) ₂ ) Titanium oxide (TiO) ₂ ) Alumina (Al) ₂ O ₃ ) Zirconium oxide (ZrO) ₂ ) Or hafnium oxide (HfO) ₂ ) Or is or

As based on metal oxides or semimetal oxides, preferablySilicon oxide (SiO) ₂ ) Hollow particles of (2)

And (4) forming.

7. The coated glass pane according to any of claims 1 to 6, wherein the size of the core (4 a) is from 10 nm to 500 nm, preferably from 10 nm to 150 nm.

8. The coated glass sheet according to any of claims 1 to 7, wherein the substrate (1) is formed as a vitreous or plastic glass sheet.

9. The coated glass pane according to any one of claims 1 to 8, wherein the volume proportion of the nanoinlays (4) in the sol-gel coating (2) is 10% to 90%.

10. Method for producing a coated glass plate, wherein

(a) The provision of nanoparticles of the type described above,

(b) The nanoparticles are provided with a shell (4 b) by atomic layer deposition,

(c) Providing a sol comprising a metal oxide or semi-metal oxide precursor,

(d) Adding nanoparticles (4 a') comprising a shell (4 b) to the sol,

(e) Applying the sol together with nanoparticles comprising a shell (4 b) onto the surface of a transparent substrate (1),

(f) Condensing the sol into a sol-gel coating (2), wherein a sol-gel matrix (3) is formed from metal oxide or semimetal oxide precursors, which is provided with a nanoinlay (4) comprising a core (4 a) formed from nanoparticles and a shell (4 b) arranged around the core (4 a).

11. The method according to claim 10, wherein the sol is condensed into the sol-gel coating (2) by treatment at a temperature of at least 400 ℃.

12. The method of claim 10 or 11, wherein the nanoparticles

Based on polymers, preferably polymethyl methacrylate (PMMA)

Based on metal oxides or semimetal oxides, preferably silicon oxide (SiO) ₂ ) Or titanium oxide (TiO) ₂ ) Or

As metal oxide or semimetal oxide based, preferably silicon oxide (SiO) ₂ ) Hollow particles of

Formed and retained in the sol-gel coating (2) as a core (4 a) of the nano-inserts (4).

13. The method according to claim 11, wherein the nanoparticles are formed on the basis of a polymer, preferably Polymethylmethacrylate (PMMA), and upon temperature treatment decompose, thereby forming pores as the core (4 a) of the nano-insert (4).

14. The method of any one of claims 10 to 13, wherein

-providing nanoparticles (4 a') dissolved in a solvent,

-the evaporation of the solvent(s),

-providing nanoparticles (4 a') with a shell (4 b) by Atomic Layer Deposition (ALD),

-the nanoparticles (4 a') comprising the shell (4 b) are dissolved in a solvent, and

-adding the solution thus obtained to a sol.

15. Use of a coated glass pane according to any one of claims 1 to 9 in buildings or land, air vehicles, wherein the sol-gel coating (2) is an anti-reflective coating, a reflectivity increasing coating, a hydrophilic or hydrophobic coating, a sun protection coating, a photocatalytic coating, a light scattering coating and/or a decorative coating.