Substrate with photocatalytic coating

A PROCEDURE WITH LATER PART OF SURFACE COATED WITH PHOTOCATALYTIC CHARACTERISTIC COATINGS

TO CREATE MEDIA

FIELD OF THE INVENTION The present invention relates to a process for forming a substrate coated with crystalline particles having photocatalytic properties on at least a portion of its surface, wherein the particles are prepared from and deposited on a photocatalytic metal oxide with at least one oxide of the photocatalytic metal B of at least one oxide of a metal M having different properties, and / or a mineral binder selected from the group consisting of at least one Si compound selected from silicon oxide compounds, and a carrier having at least a portion of its surface coated with a photocatalytic property, and a liquid phase dispersion in which crystalline titanium oxide particles and A precursor compound comprising a metal oxide B and having a crystalline state in the crystalline state is arranged and in which at least one M metal oxide and / or silicon based precursor compound can be arranged.

In particular, the present invention relates to coatings which initiate radical reactions causing oxidation of organic products by reacting semiconductor materials, in particular titanium oxide-based materials, on a metal oxide.

, 92950-1526S / FT-KO (V ϋΛ · • *

-2E coatings allow us to add new properties to the materials they cover, such as dirt repellency, antifungal and bactericidal properties, which may be combined with hydrophilic, antifouling or optical properties.

A very wide range of materials can be considered, particularly in the automotive or construction industries such as glazed products, masonry materials, cladding, flooring and flooring materials, roof tiles, roofing slates, tiles and floor tiles, in particular materials used in the building industry. employed. These materials can be made of glass, metal, glass ceramic, ceramic, cement brick, wood, stone or material obtained by the conversion of these natural materials, plastics, or fibrous rock wool type materials such as for filtering, etc.

These materials can also be grouped as transparent materials used especially for coating with glaze, for example glass, and materials made of flexible or rigid plastics such as polyester or acrylate materials such as polymethyl methacrylate (PMMA). ). Alternatively, they may be grouped as non-porous or slightly porous materials (glass) or as relatively porous materials such as tiles or ceramics.

The so-called substrate materials to be coated may also be classified as simple materials, such as glass, or substrates with superimposed layers, such as masonry materials, which are coated with a plaster.

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-3 —

Coatings containing anatase having a crystalline titanium dioxide composition and having photocatalytic properties are well known in WO 97/10186 and WO 97/10185 and are suitable for the thermal decomposition of organometallic precursors and / or titanium dioxide pre-crystallized particles. which are embedded in a mineral or organic binder.

It is an object of the present invention, on the one hand, to provide coatings whose photocatalytic properties prove to be more durable with aging of the material exposed to potential application conditions.

It is a further object of the invention to provide these coatings so as to maintain their photocatalytic properties for an extended period of time, while also increasing their durability, in particular their resistance to mechanical and chemical stress.

SUMMARY OF THE INVENTION The object of the present invention is to provide a process for forming a substrate coated with crystalline particles having a photocatalytic property on at least a portion of its surface, wherein the particles are prepared from an oxide of metal A having photocatalytic properties and coated in a crystalline state. oxide and possibly at least one oxide of M metal with a non-photocatalytic property, and / or a mineral binder consisting of at least one Si compound selected from the compounds of the silicon oxide type and the coating, => on the one hand, crystalline particles of the metal oxide A,

· «·« * «T ·

-4 <=> on the other hand at least one precursor compound of the metal oxide B of the binder, and optionally the precursor compound of the metal oxide M and / or Si in a weight ratio of metals A / (B + M + Si), and oxide and metal B oxide precursor compound, and possibly 60/40 to 40/60 in liquid phase dispersions containing a mixture of the metal oxide M and the Si compound.

The mineral binder is preferably used in at least partially crystalline form.

The oxides of metals A and B are preferably selected from the group consisting of titanium dioxide, zinc oxide, tin oxide, tungsten oxide oxides, preferably in the form of titanium oxide for both the metal oxide A and the metal oxide B.

Preferably, only the metal oxide B is used in the mineral binder and the A / (B + M + Si) ratio is used in the A / B form.

In the mineral binder, the metal oxide B is preferably used in the form of T1O2 and the silicon compound is used in the form of S1O2 and the A / (B + M + Si) ratio is thus used in the form A / (B + Si).

The particle size of the crystalline particles of the metal oxide A is suitably approx. 5 nm to 80 nm, and the size of the crystal germs is selected from 5 nm to 20 nm, and particularly used as a dispersion in at least one organic or aqueous solvent.

The organometallic precursor compound (s) is selected from the group consisting of oxide B and optionally M oxide, preferably selected from the group consisting of M (0R) 4 tetraalkoxides, MR '(0R) 3 tri-alkoxides, and metal halides, wherein R and R 'are replaced by carbon-containing radicals.

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The organometallic precursor compound (s) are preferably dispersed in the liquid phase in which the at least one chelating / stabilizing agent is present, in the case of oxide B and possibly also in the case of oxide M.

The coating is conveniently sedimented using liquid phase pyrolysis with a dispersion formed with organometallic precursors and crystalline particles.

Preferably, the coating is sedimented by a sol-gel technique using a dip sedimentation method, a cell coating, a layering coating or a spray coating method, and using a dispersion in which the organometallic compounds and crystalline particles are arranged.

Preferably, the coating is heat treated at a temperature of at least 400 ° C.

It is a further object of the present invention to provide a substrate having at least a portion of its surface coated with a photocatalytic coating comprising crystalline particles of the photocatalytic oxide of metal A and at least one oxide of at least partially crystallized metal B and / or embedded in a mineral binder made of a silica-type compound, and the porosity of the coating as measured by refractive index is greater than 40%, and in particular 45% to 65%, and a support is provided which has at least a portion of its surface provided with a photocatalytic coating in which crystalline particles of the photocatalytic oxide of the metal arranged and crystallized in a crystalline state from at least partially crystallized metal oxide B, and possibly at least one oxide of metal M and / or a silicon * · «» »ο ·

Embedded in a mineral binder composed of a silicon compound of the type -6-oxide, and in the coating, the metal content of the crystalline granules of oxide A and of the oxide B and / or the silicon compound of the mineral binder is expressed as a% + M + Si) relationship between 60/40 and 40/60.

The crystalline particles arranged in the coating preferably have a particle size of approx. 5 nm to 80 nm, and the crystal germs have a size between 5 nm and 20 nm, and the mineral binder is at least partially granular, with particles having a size between 5 nm and 25 nm, preferably between 10 nm and 20 nm.

The coating preferably comprises crystalline anatase T1O2 particles and partially crystalline TiO2.₂ based mineral binder.

In the coating, T1O2 particles, preferably in anatase form, and partially crystallized TiO2 in combination with S1O2₂ contains mineral binders.

Preferably the coating has a refractive index of at least 2, and preferably from 1.5 to 1.9, for example from 1.6 to 1.8.

Preferably, at least one compound, preferably silicon, silicon dioxide, SiOC, SiON and Si, which is impermeable to alkali metals and / or has optical and / or antistatic and / or adhesive properties.₃N₄, or a graft metal oxide, such as a fluorinated tin oxide based layer, is disposed between the support and the photocatalytic coating.

Preferably, the substrate is made of at least one glass or plastic transparent material forming a coating for a computer monitor or television screen, such as a touch screen.

The substrate is preferably arranged as part of an interior or exterior surface, in particular a conventional insulating coating, in particular one or more gas or vacuum insulating layers or any laminate or monolithic layer.

The substrate, preferably of metal or ceramic type material, masonry material, cladding or roofing material or material for cladding, preferably roof tiles and slates, stone or wood, cladding tiles, cement, plastics, any building materials, mineral or acoustic insulation materials made of cotton or textile fibers.

A further object of the present invention is to provide a liquid phase dispersion in which =&gt; crystalline titanium oxide particles, =&gt; at least one precursor compound containing a metal oxide B and having a photocatalytic state in the crystalline state and wherein &lt;=&gt; at least one metal oxide and / or silicon based precursor. Compound A can be arranged and the proportion of the particles, precursors and silicon compound represented by A / (B + M + Si) is between 60/40 and 40/60.

The titanium oxide particles are preferably present primarily in the form of anatase crystals.

The titanium dioxide particles preferably have a particle size in the range of 5 nm to 80 nm, and the crystal germ has a size of approx. It is in the range of 5 nm to 20 nm.

The metal oxide B is preferably selected from the group consisting of titanium dioxide, zinc oxide, tin oxide and tungsten oxide.

« 4 *

-8Αζ Μ metal oxide, preferably selected from the group consisting of aluminum oxide and zirconium oxide,

The precursor compounds of the oxides of metal B and metal M are preferably selected from organometallic organic compounds.

The organometallic compounds are preferably selected from the family of tetraalkoxides of formula X (0R) 4, the trialkoxides of formula XR '(0R) 3, or metal halides wherein R and R' are carbon-containing radicals and X: M or B.

The silicon compound is preferably selected from the group consisting of silicon alkoxides.

The dispersion is preferably formulated with a chelating / stabilizing agent.

Suitably, the liquid phase comprises a solvent selected from the group consisting of water, ethylene glycol, ethanol, propylene glycol and mixtures thereof.

The dispersion is preferably composed of crystalline titanium oxide particles, a metal titanium tetrabutoxide precursor compound for metal B and a tetra orthosilicate as a silicon compound having an A / (B + Si) value of about. 50/50.

With the present invention, we have attempted to reconcile the two constraints that have not hitherto been difficult to reconcile, namely to extend the photocatalytic property and the durability, more particularly the photocatalytic properties of the coating, over time. As it turned out, the catalytic effect of the coating is probably due largely to the crystalline particles in the coating which

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they are active from the beginning. Thus, an attempt was made to maximize the amount of particles in the coating. Surprisingly, however, both extremely large and extremely small amounts of particles have been found to be unsuitable for achieving the desired goals (namely, photocatalytic properties or satisfactory durability), and adjusting the ratio discovered in the context of the invention seems to be increasingly difficult to achieve. , if the type and amount of particles of oxide A are believed to affect the morphology of the binder containing oxide B, the change in the relatively pronounced photocatalytic nature and durability of the coating is not directly proportional to such parameters.

According to the process of the present invention, it is possible to choose the A / (B + M + Si) ratio within a range that allows for a greater degree of consistency between the satisfactory level of photocatalytic activity and the maintenance of a high level of photocatalytic activity over a long period. The reason for this is not fully known, at least with regard to the photocatalytic properties of the coating. However, it is believed that the mineral binder has a beneficial effect on the activity of the coating. Furthermore, it should be noted that the coatings obtained in this way have increasingly superior optical properties, particularly in terms of high light transmission and very low veil formation.

The B-oxide precursor materials, as described above, and the M-oxides or oxide precursor materials, preferably organometallic compounds, can be decomposed to the oxide, particularly when exposed to heat, when properly treated. The precursor material of the silicon compound, in particular silica

With regard to the material of the -10 precursor, it is possible to select a compound from the family of silicon alkoxides, silanes.

The process according to the invention preferably uses crystallized A oxide particles (especially titanium oxide crystals primarily in the form of anatase) in the form of agglomerates formed by crystallites and preferably in the form of agglomerates having a typical size between about 5 and 80 nm and crystallites having a typical size Between 5 and 20 nm (particularly between 5 and 10 nm) in a liquid phase dispersion, especially in a colloidal suspension liquid medium or in a dispersion containing at least one organic solvent. These dimensions correspond to the "diameters" of the agglomerates and crystallites in question, even though they are spherical in shape (even if this is not necessary; the agglomerates in question may be substantially lenticular or rod-like in shape). Instead of agglomerates and crystallites, more appropriate terminology can be used, namely that the agglomerates are in fact granules and crystallites are what can be called crystal germs. In the first approach, it is considered that the same agglomerates are found in the final coating and have little or no structural or dimensional modification. In fact, it has been observed that if the process for producing the photocatalytic coating also involves heat treatment (see below), this treatment affects these particles by structurally altering them with a significant increase in the size of the crystallites. For example, if the titanium dioxide crystallites initially have a size of 5 to 20 nm, the final coating will instead have 10 nm and

- 11 will be between 20 nm and about doubled in size (multiplier between 1.5 and 2.5). A detailed description of these granules can be found, for example, in WO 97/10185 or WO / FR96 / 02068.

Preferably, the organometallic compounds of the oxide B and optionally the oxide M are selected from the group consisting of tetraalkoxides having the structural formula M (0R) 4, wherein M is the metal of interest and R is a carbon-containing linear or bonded alkyl radical which generally contains from 1 to 6 carbon atoms. We must also remember titanium tetra-butoxide or titanium tetra-isopropoxide. You can also choose this MR '(0R)₃ type of trialkoxides, wherein R and R 'are radicals which are the same, but may be different, from the types of tetraalkoxides mentioned above or from the halides, especially titanium chlorides. Because these precursor compounds are highly hydrolyzable and reactive, it is desirable to co-dissolve them in at least one chelating / stabilizing agent, such as β-diketone, such as acetylacetone (2,4-pentadiene), benzoylacetone (1-phenyl-1, 3-butadiene) and diisopropylacetylacetone or other acetic acid selected from the group consisting of diethanolamine or glycols, such as ethylene glycol or tetraoctylene glycol. The concentration of the precursor in the solution (at a given solids content) can then be controlled by preparing suitable solutions using one or more organic solvents.

The simplest way of carrying out the process according to the invention is to pre-mix the coating from a dispersion containing a precursor and from a dispersion containing the granules into a single dispersion before applying the latter to the carrier or dipping the carrier into this dispersion. , although it is acceptable to apply the coating from a plurality, preferably two different dispersions, without first mixing them.

Our first type of settling technique is the so called. is called hot sedimentation, in which, at the time of contact between the dispersion and the support, the support is at a temperature sufficiently high to allow thermal decomposition of the precursor: a technique called liquid-phase pyrolysis.

The second type of technique is the so called. cold deposition, whereby during dispersion and contact of the carrier, the carrier is at room temperature or at very low temperature which is too low to cause decomposition of the precursor; sol-gel type techniques, pickling, cellular coating, layered coating and spray coating.

Cold deposition techniques require contacting the dispersion and contact with the substrate after heat treatment to cure the coating and ensure that the precursors are completely degraded. However, this may also be advantageous for hot sedimentation techniques as it may have a cohesion enhancing effect in the coating and at least partially favor the crystallization of the binder resulting from the decomposition of the precursors. This treatment is carried out at a temperature of at least 400 ° C, for example above 450 ° C, in particular in the range of 550 ° C to 500 ° C, provided the substrate is resistant to this type of treatment, for example if the substrate is glass, ceramic, or has a glass ceramic matrix.

The substrate of the invention formed by said process has a photocatalytic coating on at least a portion of its surface,

It contains crystalline particles of photocatalytic properties of at least partially embedded metal oxides embedded in a crystalline mineral binder, wherein the binder also consists of an oxide of the metal B in a crystalline state having a photocatalytic property. The carrier exhibits a high porosity value, preferably greater than 40% and preferably between 45 and 65%. This porosity can be calculated indirectly by measuring the refractive index of the coating by comparing it with the refractive index of a completely solid material. This indirect process is also fairly representative of the porosity and surface morphology of the coating, since the refractive index measurement at least partially takes into account the degree of surface roughness of the layer.

(Other indirect methods measure the weight of a coating deposited on a unit surface of a substrate that corresponds to a given coating thickness.)

High porosity offers significant practical advantages. First, it allows us to reduce the refractive index of the material and to change the visual appearance of the material. In the case of a coating based on titanium oxide (where crystalline titanium oxide is present, in particular anatase crystalline particles and a binder based on titanium oxide, possibly combined with silica), at least 2, preferably from 1.4 to 1.8, and preferably By reducing the refractive index value from 1.7 to 1.8, the well-known reflective nature of the surface can be significantly reduced.

Furthermore, the porosity of the coating is related to the high surface roughness, which greatly increases the coating surface, which is favorable for photocatalytic activity.

Finally, this surface roughness, which is suitably of two types, as described in WO 98/23549, gives the coating an enhanced and durable hydrophilic property, thus rendering it resistant to rain and mist (water droplets spread into an invisible film). and, by catching rainwater, facilitates the removal of mineral contamination. Surprisingly, this high porosity does not mechanically weaken the coating.

The present invention also provides a support having a photocatalytic coating on at least a portion of its surface comprising crystalline particles of metal A oxides embedded in at least partially crystallized mineral binder, wherein the binder is also a photocatalytic oxide of metal B and optionally M It consists of a non-photocatalytic oxide of a metal and / or a silicon oxide type of silicon. The A / (B + M + Si) ratio is preferably in the range of 60/40 to 40/60% by weight with respect to the weight of the metals A, Β, M and possibly silicon, where the metals in the mixture of A oxide particles and B and the silicon is present in the Si compound in the mineral binder.

It should be noted that the carrier according to the invention may have a certain degree of dustiness, for example if it is a roof tile or a fibrous material (e.g. rock wool). If the substrate is said to have a certain photocatalytic coating, it is understood that the substrate is deposited on its surface, but the substrate may be impregnated to a certain depth if it is a porous or fibrous material. Therefore, the amount of coating can be expressed as the thickness of the layer on the non-porous substrate, e.g.

- 15 - even if the substrate has a certain porosity.

The coating according to the invention, either formed by the above process and / or corresponding to the coatings whose characteristic properties are described above, preferably has the following structure (especially when both of the oxides A and B are based on titanium dioxide): it comprises crystalline particles having a particle size between 5 and 80 nm, crystal germs having a size between 5 and 20 nm (as described above), and a mineral binder surrounding the crystalline particles, which is at least partially granular and has a particle size between 5 and 25 nm. nm, preferably between 10 and 20 nm. These particles, which are essentially spherical in shape, are not fully crystallized, although they may be partially crystalline, but to a small extent that is difficult to measure and encapsulate, encapsulate and bond the particles.

The carrier of the present invention is provided with a photocatalytic coating comprising titanium dioxide particles substantially in the form of anatase and a mineral binder which is a mixture of partially crystallized titanium dioxide and silica. The coating has a refractive index up to 2, preferably between 1.5 and 1.9, or between 1.6 and 1.9 or 1.6 and 1.8.

It has been mentioned that according to one embodiment of the invention at least one intermediate layer is interposed between the substrate and the photocatalytic coating, where the layer or layers preferably have different functions (optical function, insulation against materials which tend to leave the carrier). such as alkali metals and anti-static function, possibly an adhesive layer, etc.).

It may be based on a silicon compound (e.g., silicon, silica, silicon oxonitride, silicon oxide, and S 3 N 4) or optionally grafted metal oxide (F: SnO 2, Sb: SnO₂, etc.) intermediate layers.

Such coated substrates are also mentioned in the introductory part of the present specification. These may be transparent materials, especially glass or plastic materials forming the exterior coating of buildings or vehicles, or television sets, monitors (such as touch screens), or any laminated or monolithic coating (consisting of a single glass pane or a single sheet of plastic). It is also advantageous if the transparent substrate provided with the coating according to the invention is formed into a multiple insulating layer so that the coating is on the inner or outer side of the layer. This may be a conventional insulating layer having one or more layers of intermediate gas, such as that produced by Saint-Gobain Vitrage BIVER, or CLIMALIT D, or CONTRATHERM, CONTRASONOR, CONTRARISC, or called a "vacuum" layer structure, wherein the gaseous barrier layer is replaced by a vacuum layer such as that described in EP 645 516. Particularly in the latter case, it is advantageous to apply the coating as an outer layer on the outside of the insulating layer in order to prevent the formation of moisture due to the hydrophilic nature of the coating.

The coating according to the invention is also advantageous for polished walls of refrigerators or freezers. Practically a lot of materials can serve

As a carrier for the coating according to the invention, for example metal, ceramic, plastic or cement based materials and all the aforementioned materials used in architecture for masonry and for roofing such as roof tiles and roofing slate. They can also be substrates for covering exterior, interior substrates or walls of prefabricated space elements such as tiles.

It is also possible for the coating to be deposited on a fibrous material or mineral wool type material to provide thermal or acoustic insulation or to be reinforced with a textile fiber. These fibrous materials may be used in screening processes such as: bactericidal and fungicidal properties, as well as antifouling properties.

As mentioned above, the invention also relates to a liquid phase dispersion as described in more detail above, which can be used to manufacture the photocatalytic coating of the invention. Said dispersion preferably comprises a solvent selected from the group consisting of water, ethylene glycol, ethanol, propylene glycol and mixtures thereof.

The crystalline phase of the titanium dioxide particles of the dispersion of the present invention is preferably primarily anatase crystal. This means that the titanium dioxide particles in the coating have an anatase content greater than 50% by weight. Preferably, the coating particles have an anatase content of greater than 80%. The crystallinity and the properties of the crystalline phase are examined by X-ray diffraction.

The dispersions of the present invention are generally formed by admixing a dispersion of titanium dioxide particles with a solution of a precursor compound or a silicon compound. Depending on the nature of the compound employed, it is also possible to add additional additives, such as additional solvents, surfactants or stabilizers, during the mixing process. The mixing can be enhanced by ultrasonic mixing of the dispersion.

The invention will now be exemplified below. with reference to the accompanying drawings. In the drawing it is

First Fig. 6A is a schematic representation of the structure of a photocatalytic coating according to the invention;

Second Figure 3B is a scanning electron microscope (SEM) view of the structure of a photocatalytic coating according to the present invention.

The first set of examples relates to the deposition of a dirt-resistant coating 3 based on titanium oxide based on a substantially transparent substrate.

The substrate 1 is perfectly smooth, 15 x 40 cm² area and 4 mm thick Si-Na-Ca glass. It goes without saying that the invention is not limited to this particular type of glass. In addition, the glass surface may be curved instead of smooth.

Between the coating 3 and the support 1, a thin layer 2 of silicon oxide, i.e. SiOC-based, may be placed which forms a barrier layer against diffusion of the alkali metals, since this diffusion adversely affects the photocatalytic properties of the coating 3 and / or , chemical vaporization may also precipitate a layer having an optical function and a thickness of about 50 nm.

Two different methods of cold sedimentation were used, namely a sedimentation process in a bath at a flow rate of 5 to 30 cm / min.

- It consists of a 19-cell coating with pickling and a settling method based on the principle of spraying. cold liquid spray. These well-known techniques are described in detail in the above patent applications.

The coatings were pelleted from a dispersion of starting solution I and II. dispersion mixture was obtained:

Solution I: This solution contains an organometallic precursor compound of a titanium oxide-based mineral binder: essentially titanium isopropylate, i.e. Ti (OCH (CH₃)₂) 4, which is dissolved in ethanol solution with acetylacetonate CH₃-CO-CH₂-CO-CH 3 is stabilized;

II. Dispersion: ethylene glycol liquid phase containing crystalline particles having photocatalytic properties having the following properties:

φ specific surface area of ​​the granules:&gt; 350 m²/ g =&gt; particle size «40 nm&gt; =&gt; the crystallites forming the particles have a size of 7 nm o the crystalline phase is more than 80% anatase.

Solution I and II. the composition of the dispersion obtained by mixing the dispersion was adjusted so that the appropriate Ti (₂)/You₍i) the ratio is reached, which is actually the ratio of II. mass of titanium (2) from dispersion granules relative to titanium (1) from precursor in solution (this ratio can be conventionally expressed as the weight of titanium oxide from the particles divided by the weight of titanium oxide from the metal precursor) 100% of precursor converted to oxide: the two values ​​are the same).

-20Αζ 1st -7th samples refer to cellular sedimentation cured sedimentation under similar sedimentation conditions, that is, in the same bath, at a flow rate of 6 cm / min and with the same titanium concentration (namely 3% solids content which is converted to oxide) as in I. derived from a precursor in solution.

After settling, the substrates were subjected to heat treatment for approx. At 450 ° C to 500 ° C for at least 30 minutes.

In Table 1:

n&gt; the ratio Ti (2) / Ti (D, the ratio explained above, without the unit;

&lt;=&gt; this thickness of the coating 3 in nm;

=&gt; D₆s is the value of Tl of the light transmittance measured with the light source in%; o is the value of the "lattice", expressed as a percentage of the diffused transmission and the transmission of light over the entire visible region.

First Spreadsheet

<td></td><td>Ti (2) / Ti (i)</td><td>e (nm)</td><td>Tl (%)</td><td>haze (%)</td>

<td>Sample 1</td><td> 0/100</td><td> 20</td><td> 88,5</td><td> 0,88</td>

<td>Sample 2</td><td> 20/80</td><td> 20-30</td><td> 89,6</td><td> 0,27</td>

<td>Sample 3</td><td> 40/60</td><td> 40-50</td><td> 89,5</td><td> 0,76</td>

<td>Sample 4</td><td> 50/50</td><td> 40-60</td><td> 90,2</td><td> 0,50</td>

<td>Sample 5</td><td> 60/40</td><td> 60</td><td> 90,5</td><td> 0,61</td>

<td>Sample 6</td><td> 80/20</td><td> 30-40</td><td> 89,7</td><td> 0,44</td>

<td>Sample 7</td><td> 100/0</td><td> 30-40</td><td> 90,3</td><td> 1</td>

-21 Sample 8 was prepared using the dispersion used in Sample 4, but was applied to substrate 1 by a cold-spray technique known as "blasting". airless spray nozzle at 0.7 bar (0.7 '10')⁵ Pa). The thickness of the formed layer after curing for 30 minutes at a temperature of 450-500 ° C is approx. 35 to 60 nm, T_L value is 88.6% and the lattice value is 0.6% as in Table 1.

Samples 1 through 8 were evaluated for photocatalytic activity before and after treatment with simulated coating accelerated aging.

The photocatalytic activity was measured as follows:

ι =&gt; O - the test is applied for approx. 15 cm²ο Θ - measure sample weight and substrate thickness 1, Tl and vein value o © - spray-settle solution of palmitic acid (8 g acid in 1 liter chloroform) for 3-4 consecutive steps where the distance between the glass and the nozzle was 20 cm and the substrate 1 was positioned vertically,

- the weight of the sample after palmitic acid sedimentation was measured to determine the deposited acid thickness in nm,&gt; =&gt; Θ_Lmeasured after settling, =&gt; Θ - the change in veil was measured as a function of UVA irradiation time (about 30 V / m²), =&gt; β - graphically determined the time at which the veil decreased by 50%: this time Τ_Ί/ 2 (disappearance), • »:

-22 &lt;=&gt; © - the photocatalytic activity of the 3 coatings was evaluated as a function of the vanishing rate v (nm / h), which can be interpreted as follows:

v (nm / h) = palmitic acid layer thickness (nm) / 2 · T_1/2 (disappearance) (h).

The aging of the coating consisted of subjecting it to mechanical abrasion as follows:

=&gt; sample size: 7 cm x 15 cm, g&gt; applied load: 600 g, &lt;=&gt; abrasion area: 1.5 cm², n cycles (1 cycle = single forward and backward movement of the abrasion pad with felt), n = 200 and 500.

Table 2 gives for each sample: v1 disappearance factor before abrasion, =&gt; v2 disappearance factor after 200 cycles, = 9 v3 disappearance factor after 500 cycles.

-23 —

Second SPREADSHEET

<td></td><td>v1 (0 cycles)</td><td>v2 (200 cycles)</td><td>v3 (500 cycles)</td>

<td>Sample 1</td><td> 20</td><td> 10</td><td> 0</td>

<td>Sample 2</td><td> 40</td><td> 5-10</td><td> 0</td>

<td>Sample 3</td><td> 35</td><td> —</td><td> « 10</td>

<td>Sample 4</td><td> 70</td><td> 10-20</td><td> * 10</td>

<td>Sample 5</td><td> 35</td><td> —</td><td> «5</td>

<td>Sample 6</td><td> 20</td><td> 1-2</td><td> 0</td>

<td>Sample 7</td><td> 20</td><td> 0</td><td> 0</td>

<td>Sample 8</td><td> 40</td><td> —</td><td> 7</td>

Analyzes have shown that the coatings 3 of patterns 3, 4, and 5 have a structure substantially similar to that shown in Figure 1, which represents the glass substrate, the SiOC layer 2 and the coating 3. This coating 3 contains granules or crystalline agglomerates 5, which contain enrichments of amorphous or slightly crystalline T1O2 particles 4, which form the mineral binder of the coating 3.

The scanning electron microscope photograph of Figure 2 depicts Pattern 4 and provides information about the surface of Pattern 4: a rough surface that provides a large overall surface for the coating 3.

It should be noted that the refractive index of Sample 4 is approx. 1.65. In the first approach, considering the refractive index of the body of T1O2 is 2.4

-24 shows that the porosity of the coating is approx. (2.4-1.65) / (2.4-1), which is ca. 54%. The 3 coatings corresponding to sample 4, when activated for 20 minutes with UVA light and then placed in the dark, exhibit a strong hydrophilic property: the 3 coatings and water droplet φ wetted! periodically, this angle remained less than 10 ° for at least 20 days in a dark environment.

From these data, the following conclusions were reached: Samples 3, 4, 6, 8 and especially 5, in which Ti₍₂) / Ti (i) ratio is 50/50, they have all the favorable properties, namely:

a high T1, a low lattice value and a refractive index of less than 2, the coating 3 having a very favorable visual appearance;

&lt;=&gt; satisfactory photocatalytic activity, which is retained even when the coating is subjected to a mechanical influence on its durability, so that these coatings can be used in real conditions, such as exterior cladding, since they have an acceptable lifetime. Practically only these samples show some photocatalytic activity, although to a lesser extent after 500 abrasion cycles.

A second series of 3 coatings of the same type were prepared on the same solution I and II. based on dispersion. The conditions of the sedimentation were the same as in Figures 1-7. except that the bath flow rate was higher, i.e. 24 cm / min. The other difference was with substrate 1: although it was the same glass, it was pre-coated with a first SiOC layer of 50 nm thick, which was sedimented with CVD, and then a second 450 nm thick fluorine-grafted tin layer was applied.₂, and &lt;&lt;· · -&gt; · wr '

-25 powder by pyrolysis in known manner. Further, in this series of samples, the Q content of the photocatalytic coating 3 was determined not by measuring its thickness, but by measuring the amount of material per unit area of ​​substrate 1, which was pg / cm²expressed in.

Samples were subjected to photocatalytic activity prior to the abrasion test, which corresponds to the above v1 value. The qualitative assessment of the coating's durability was simply done by wiping it with a cloth:

means that the coating 3 is very resistant, "+" means that it is still sufficiently resistant, and means that the coating 3 is almost worn out by wiping with a cloth.

Table 3 shows Figures 9 to 13. summarizes the values ​​for the samples: Ti (2) / Ti (i), Q, v1 (have the same meaning as in Table 1), and the results of the cloth wipe test:

Third Spreadsheet

<td></td><td>YOU₍₂) / Ti (1)</td><td>Q (pg / cm²)</td><td>v1 (nm / h)</td><td>result of wiping cloth</td>

<td>Sample 9</td><td> 0/100</td><td> 22</td><td> 18</td><td> ++</td>

<td>Sample 10</td><td> 20/80</td><td> 24</td><td> 128</td><td> +</td>

<td>Sample 11</td><td> 40/60</td><td> 23</td><td> 159</td><td> +</td>

<td>Sample 12</td><td> 50/50</td><td> 25</td><td> 231</td><td> +</td>

<td>Pattern 13</td><td> 100/0</td><td> 23</td><td> 222</td><td> -</td>

-26The same tendency can be observed in this table as in the first series, namely that when the same or almost the same amount of 3 coatings was applied, the optimum was reached for the samples 11 and 12, where Ti (2) / Ti (ij ratios of 40/60 to 50/50. Only sample 12 shows above 200 photocatalytic activity and adequate durability.

A third series of samples refers to 3 coatings in which T1O2 particles are used in the dispersion used in all the above examples but with a hybrid binder in which TiO2 is combined.₂-SiO₂-with.

The solution containing the precursor of binder 4 has the following composition: solvent: ethanol and ethylene glycol 75/25% by weight, stabilizer: acetylacetonate,

TiO₂ as precursor: titanium tetrabutoxide (TBT), · + S1O2 precursor: tetraethyl orthosilicate (TEOS).

The proportions of TBT and TEOS were controlled so that TiO₂/ SiO₂ should be 15/85% by weight of the solution (assuming that each TBT is converted to TiO₂and every TEOS is transformed into SiO₂DA).

This solution was then added to the dispersion containing the granules, which was used in the above samples, in proportions such that the desired Ti_szerncsék / (Tip_rekurzor + Si_precuror) f ratio, achieved. (The solids content of the solution is 3%.)

The conditions of the sedimentation and the support 1 were the same as those used in samples 9-13.

• ·

-27 Table 4 shows the above value of the ratio r, the value of the ratio v1 above, the reflection of the coated surface R1 (%), and Tj. (The change in GST observed after the 500 abrasion cycles described for the first series of samples is also indicated as the ratio η, which is the ratio between the amount of Ti and the amount of Si in the oxide state:

n = thio₂ granules / (TIO₂binder + SiO₂ binder) The table also shows the Ch value, the total TiO in the coating₂amount (granules and TiO₂derived from the titanium precursor) pg / cm²and Q₂ value, calculated as the total weight of the 3 coatings, is also pg / cm²-in.

4th Spreadsheet

<td></td><td>r</td><td>rí</td><td>v1</td><td>rl</td><td>ΔΤ | _</td><td>Qi</td><td>q₂</td>

<td>Sample 14</td><td> 45,1/54,9</td><td> 40/60</td><td> 8</td><td> 12,5</td><td> 0</td><td> 8,8</td><td> 18,2</td>

<td>Sample 15</td><td> 55,3/44,7</td><td> 50,50</td><td> 40</td><td> 10</td><td> 1</td><td> 9,3</td><td> 16,3</td>

<td>Sample 16</td><td> 65/35</td><td> 60/40</td><td> 45</td><td> 14 ·</td><td> 4</td><td> 10,1</td><td> 15,4</td>

By adjusting the solids content of the solution and by controlling the flow rate, the coating was repeated with a r = 55.3 / 44.7 ratio and the amount of the deposited 3 coatings changed.

Table 5 provides data for these additional samples, starting from sample 15, and quantifying Q in pg / cm², the appropriate thickness e in nm (if any), the value of v1 in nm / h,_Land ΔΤ | _ and found the following:

-285. Spreadsheet

<td></td><td>Q</td><td>e</td><td>v1</td><td>rl</td><td>THROUGH_L</td>

<td>15a. sample</td><td> 17</td><td> 110</td><td> 42</td><td> 8,5</td><td> 1,5</td>

<td>15b. sample</td><td> 33</td><td> —</td><td> 88</td><td> 12,1</td><td> 2,5</td>

<td>15c. sample</td><td> 49</td><td> 460</td><td> 130</td><td> 11</td><td> 0,8</td>

From this third series of samples it can be seen that we have obtained some advantages over SiO₂ by adding it to the binder 4, since this material does not participate in photocatalysis but allows the coating 3 to be more homogeneous and increase its durability. It can also be seen that although the r ratio is key, other parameters can be taken into account, in particular the Q value, which is preferably between 15 and 45 pg / cm² in order to influence both the cost of producing the 3 coatings and the effect of this thickness on the visual appearance.

It goes without saying that the invention is not limited to these samples. It is within the scope of the invention to enhance the photocatalytic activity of the group of crystals 5 by coating the coating material on the crystal lattice or by coating the granules with said additives of the types Fe, Cu, Ru, Mo, Bi, Ta, Nb, Co , Ni, Va, etc. as disclosed in the aforementioned WO 97/10185.

It is also within the scope of the present invention to add a mineral binder 4 which contains oxides which are not in the crystalline state or only slightly photocatalytic, for example other oxides are added to the dispersed precursors which are SiO 2.₂ types such as tetraethoxysilane (TEOS).

The aforementioned A / (B + M + Si) ratio in the range 40/60 to 60/40 is optimal, but at lower demand levels it is also assumed to be in the range 35/65 to 40/60 and 65/35 to 60/40 may.