Preparation of material with photocatalytic properties containing titanium oxide for coating glass or vitroceramic sheets for wide range of building, vehicle and commercial glazing applications

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PROCESS FOR PREPARING A PHOTOCATALYTIC COATING INTEGRATED IN THE HEAT TREATMENT OF GLAZING

The present invention relates to glazing provided with a coating with photocatalytic properties, of the type comprising titanium oxide at least partially crystallized, in particular in the anatase form.

Several techniques are known for the preparation of such a coating, in particular on a glass sheet, with a view to obtaining a product of high optical quality. For example, a sol-gel process is available consisting of depositing titanium dioxide precursor in solution, then heating so as to form the crystallized dioxide in anatase form, a pyrolysis process, in particular in the gas phase (Chemical Vapor Déposition - CVD - ), in which precursors of titanium dioxide in the gas phase are brought into contact with the hot substrate, optionally during cooling, in particular the atmosphere side of a glass leaving the float.

Cathodic sputtering, known from patent WO 97/10186, is also proving to be particularly advantageous in terms of industrialization. It is a vacuum technique which makes it possible, in particular, to very finely adjust the thicknesses and the stoichiometry of the deposited layers. It is generally assisted by a magnetic field for more efficiency. It can be reactive: we then start with an essentially metallic target, here based on titanium (possibly alloyed with another metal or with silicon), and the sputtering is carried out in an oxidizing atmosphere, generally an Ar / O mixture.₂. It can also be non-reactive; we then start with a so-called ceramic target which is already in the oxidized form of titanium (possibly alloyed). Titanium dioxide produced by sputtering is generally amorphous or poorly crystallized and it is necessary to heat it subsequently in order for it to crystallize in the photocatalytically active form.

Application WO 02/24971 describes the deposition on glass of coatings of partially crystallized anatase titanium dioxide, by cathodic sputtering at a relatively high working pressure of at least 2 Pa; in a first variant, the substrate is at 220-250 ° C. for example during the deposition, a conventional annealing at approximately 400 ° C. then being carried out if necessary; in a second variant, the deposition is carried out on a substrate at ambient temperature, then the assembly is heated to 550 ° C. at most, for a few hours.

Thus, in view of WO 02/24971, if particular properties requiring a heat treatment of annealing, bending, tempering or the like at more than 600 ° G, or even up to 700 ° C in certain cases, were sought for a TiO glazing₂photocatalytic prepared by magnetron sputtering, the specialist would deposit the TiO₂ after this heat treatment, then activate it by applying a more moderate temperature. On the other hand we wait until the exposure of TiO₂ prepared by a CVD process at temperatures above 600 ° C promotes reuse, the crystalline rutile form being much less photocatalytically active than the anatase form.

Now, the inventors have succeeded in obtaining high photocatalytic activity and high optical quality by crystallizing titanium dioxide at the temperatures of conventional heat treatments of glass, which makes it possible to obtain this crystallization by quenching alone, or the like, and to avoid an additional subsequent heating operation at a more moderate temperature.

To this end, the subject of the invention is a process for preparing a material with photocatalytic properties comprising titanium oxide at least partially crystallized, in particular in anatase form, characterized in that it uses temperatures exceeding 600 ° C. This therefore results in better integration of this preparation in various industrial processes, which are thereby simplified by the elimination of a specific operation of crystallization at relatively low temperature. The duration of these processes is thereby shortened. The devices are reduced because heating means simultaneously perform two functions. Finally, the cost of these methods is reduced.

According to preferred embodiments and / or having particularly motivated the invention:

- the process uses temperatures exceeding 630 ° C;

- It implements a toughening and / or bending treatment of a glazing (that is to say in particular temperatures which can reach 700 ° C.).

In a manner providing excellent results in the exemplary embodiments below, the method of the invention comprises the deposition of a coating of titanium oxide on a first face of a first transparent or semi-transparent substrate of the type. glass, vitroceramic which, optionally, has been provided beforehand with one or more stacks of functional layers and / or functional layers, the nature of which will be described in detail below.

According to other interesting characteristics of the process of the invention:

- It comprises the deposition, on the second face of said first transparent or semi-transparent substrate or on a second face belonging to a second transparent or semi-transparent substrate, of one or more stacks of functional layers and / or functional layers, the nature of which is also detailed below (thus the process of the invention makes it possible to obtain transparent or semi-transparent products with mechanical properties obtained by heat treatment at relatively high temperature, and capable of exhibiting the widest range combined functionality);

- Said implementation of temperatures exceeding 600 ° C is subsequent to the deposits on said first and second faces (however any other variant in which these temperatures are not applied after the deposition on the second face is not excluded from the invention , as far as they are after the deposit on the first side; in other words, the deposition product on the second face may not be subjected to temperatures exceeding 600 ° C, for example by carrying out the deposition on the second face after application of these temperatures or, in the case where the second face belongs to a second substrate, this one may not be associated with the first - in a double glazing, laminated glazing ...- only after it has been subjected to these temperatures -association of a first tempered glass substrate and a second non-tempered glass-. Otherwise, also in accordance with the invention, the products deposited on the first and second faces are heated simultaneously to more than 600 ° C, which can be advantageous and economical, the second substrate if there is then additionally also heat treated);

- The deposits on said first and second faces are carried out by cathodic sputtering and advantageously, in this case, in line and simultaneously or almost simultaneously, in a substantially identical direction and in an opposite direction (in particular the use of an installation is intended cathode sputtering assisted by a magnetic field from above and below, commonly known as "sputter up and down", wherein the first and second faces are horizontal and oriented upwards and downwards respectively, so that they are brought into contact by spray cones of vertical mean direction descending - down - for the thermal control stack, respectively ascending - up - for TiO₂better able to resist roller abrasion). However, any other orientation of the first and second faces is not excluded from the invention: vertical, more or less inclined.

A subject of the invention is also a glass sheet, at least one face of which bears a coating of a material comprising titanium oxide, characterized in that it is capable of being or has been subjected to a heat treatment at more than 600 ° C, such as tempering and / or bending, while preserving the photocatalytic activity and the optical quality required for an anti-fouling glazing.

In the first place, the heat treatment at more than 600 ° C does not affect the product to such an extent as to make it unsuitable for use as an anti-fouling glazing; it was even observed, not without surprise, that the photocatalytic activity is comparable, or even better in certain cases, to that obtained at the end of heat treatments according to the teaching of the aforementioned application WO 02/24971 (for example annealing at 500 ° C for 1 hour).

The use of temperatures above 600 ° C is also not incompatible with a high optical quality, which essentially refers to the absence of defects visible to the eye: blur, spots or pitting, cracks . Advantageously from an industrial point of view, the average colorimetric variation in reflection on the photocatalytic coating side induced by this heat treatment, ΔΕ, is at most 2.8, preferably at most 2.3; this expresses the fact that the colorimetry in reflection of the final product is close to that of the deposition product before heat treatment. ΔΕ is calculated by the equation

ΔΕ = (AL² + Aa *² + Ab *² )^1/2 in which Δ expresses the variation of a parameter induced by the heating, L the lightness, a * and b * the chromaticity coordinates (colorimetry system L, a *, b *: the positive values ​​of a * go towards the red , negative values ​​towards green, positive values ​​of b * go towards yellow and negative values ​​towards blue; the area of ​​values ​​of a * and b * close to 0 is achromatic).

Other objects of the invention consist of

a monolithic glazing, laminated, single or multiple, comprising a glass sheet as described above;

a monolithic, laminated, single or multiple glazing, of which at least a first face of at least a first constituent glass sheet bears a coating of a material with photocatalytic properties, obtained in accordance with the process of the invention.

According to other preferred characteristics of this glazing:

- Under said coating of a material with photocatalytic properties, said first face carries one or more stacks of functional layers and / or functional layers, comprising at least one layer forming a barrier to the migration of alkalis from the glass likely to result from the application temperatures exceeding 600 ° C (for the latter we know S1O2, S13N4, AIN by magnetron sputtering, SiOC by CVD ..., for other functionalities, the stacks and layers provided below for said second face can be used, excluding the hydrophilic and hydrophobic layers, intended to be in contact with the atmosphere);

- the second face of said first glass sheet or a second face belonging to a second constituent glass sheet carries one or more stacks of functional layers and / or functional layers chosen from a thermal control stack such as anti-solar, low -emissive, a stack or a layer with optical functionality such as anti-reflection, filtration of light radiation, coloring, diffusing, a layer of an anti-fouling photocatalytic material in particular of the high activity type, a hydrophilic layer, a hydrophobic layer, an array of conductive wires or a conductive layer, in particular heating, antenna or anti-static, alone or in combination.

Another object of the invention is the application of this glazing as "self-cleaning" glazing, in particular anti-fog, anti-condensation and anti-soiling, in particular glazing for buildings of the double-glazing type, glazing for vehicles of the windshield type, rear window, automobile side windows, rear-view mirror, glazing for trains, planes, boats, utility glazing such as aquarium glass, display case, greenhouse, interior furnishings, street furniture (bus shelters, advertising panels. ..), mirror, computer type display system screen, television, telephone, electrically controllable glazing such as electrochromic, liquid crystal, electroluminescent glazing, photovoltaic glazing.

The invention is illustrated below by way of examples.

EXAMPLE 1

In this example we compare the transformation of TiO₂ amorphous obtained by magnetron sputtering in its active form by industrial quenching on the one hand, annealing at 500 ° C for 1 hour on the other hand.

The photocatalytic activity is evaluated at the end of the two treatments by means of the stearic acid photodegradation test followed by infrared transmission, described in application WO 00/75087.

A 60 nm thick layer of SiOC is deposited on three samples of clear soda-lime glass 4 mm thick by gas phase pyrolysis (CVD) as described in application WO 01/32578, and on three others a layer of SiO₂ 100 nm thick by magnetron sputtering.

On the six samples, TiO coatings are formed₂ variable thicknesses by magnetron sputtering at a working pressure of 26.10 '³ mbar, then the photocatalytic activity thereof is evaluated as indicated above after the two aforementioned heat treatments.

The results are shown in Table I below.

Table I

<td>Test n °</td><td>Thickness of TiO₂ (nm)</td><td>Undercoat</td><td>TAS after quenching (10 '³cm '¹miri¹)</td><td>TAS after 1 hour at 500 ° C (10 '³cm '¹miri¹)</td>

<td> 1</td><td> 25</td><td>SiO₂</td><td> 7,9</td><td> 4,7</td>

<td> 2</td><td> 25</td><td>SiOC</td><td> 10,2</td><td> 2,3</td>

<td> 3</td><td> 39</td><td>SiO₂</td><td> 11,9</td><td> 6,2</td>

<td> 4</td><td> 39</td><td>SiOC</td><td> 3,4</td><td> 7,3</td>

<td> 5</td><td> 146</td><td>SiO₂</td><td> 10,5</td><td> 1,2</td>

<td> 6</td><td> 19</td><td>SiOC</td><td> 6</td><td> 3,7</td>

Contrary to what was expected, not only does industrial hardening not reduce the photocatalytic activity in a prohibitive manner, but this is at least comparable to that resulting from TiO activation treatments.₂ known from the state of the art as shown in particular by WO 02/24971 already cited. Indeed the activity is lower after quenching only in test n ° 4.

Therefore, the TiO₂ prepared here is hardenable from the point of view of photocatalytic activity, even by implementing barrier sublayers to the diffusion of alkalis of the glass of usual thicknesses.

EXAMPLE 2

Tests 1, 3 and 5 above, as well as tests n ° 7 and 8 characterized by respective thicknesses of photocatalytic coating obtained of 27 and 19 nm (same barrier sublayer of SiO₂, same conditions for preparing TiO₂ than in tests 1, 3 and 5), are subject to a measurement of the mean colorimetric variation in reflection on the coating side induced by industrial hardening, ΔΕ. The meaning of the different parameters in the colorimetry system L, a *, b * and the equation for calculating ΔΕ from AL, Aa *, Ab * are as described above.

The results are shown in Table II below.

Table II

<td>Test n °</td><td>AL</td><td>Aa</td><td>Ab '</td><td>ΔΕ</td>

<td> 1</td><td> 1,02</td><td> 0,23</td><td> -0,46</td><td> 1,14</td>

<td> 3</td><td> -0,08</td><td> 0,77</td><td> -2,10</td><td> 2,24</td>

<td> 5</td><td> 1,40</td><td> -0,47</td><td> 0,91</td><td> 1,73</td>

<td> 7</td><td> 1,70</td><td> -0,57</td><td> 0,04</td><td> 1,79</td>

<td> 8</td><td> 1,39</td><td> -1,15</td><td> -2,09</td><td> 2,76</td>

The relatively low average colorimetric variation values, or even in some cases ideally less than 2, express a slight variation in color in reflection on the photocatalytic coating side after industrial hardening of all the coatings, which excludes the unwanted obtaining of colorimetric dipped products. in reflection too modified during quenching. It becomes easier to predict the final color before quenching.

EXAMPLE 3

This example concerns a double glazing consisting of two sheets of glass 4 mm thick between which is interposed an air space 15 mm thick. In this example and the following ones, the face 2 of the double glazing, that is to say the face in contact with the air space of the sheet of glass intended to be installed closest to the outside atmosphere (and not to that intended for use on the inside of a building), is coated with a stack of thermal control layers, manufactured by magnetron sputtering. This process is particularly practical for depositing the widest range of types of layers, by varying them and precisely controlling the thicknesses, on an industrial scale.

Here this stack is low-emissive, that is to say reflecting thermal infrared radiation (wavelengths of the order of 10 μm) and capable of retaining heat inside a building for example. .

From an optical point of view, the association of the thermal control stack on face 2 and a stack obtained by magnetron sputtering and comprising TiO is studied.₂ photocatalytic and SiO underlayer₂ barrier to the diffusion of alkalis on face 1, intended to be in contact with the external atmosphere.

In the following, we denote by X, respectively Y, the basemissive stacks differing from that of example 2 of application EP 0 718 250 A2 only by modifying the thickness of the layer (2) in 25 nm, respectively layers (2) in 19 nm and (3) in 29 nm.

The following four glazing compositions are tested, defined below only by the glass sheet on the exterior side:

3a: 4 mm glass / 36 nm S13N4 / X

3b: 18 nm TiO₂/ 150 nm SiO₂/ 4 mm glass / X

3c: 18 nm TiO₂/ 75 nm SiO₂/ 9 nm S13N4 / 63 nm SiO₂/ 4 mm glass / X

3d: (same photocatalytic stack as 3b) ... / 4 mm glass / Y

In this example as well as in Examples 4-7 below, all the stacks were subjected to industrial quenching. The optical characteristics of the glazing in transmission are evaluated, reflection on the “interior” side of the building (that is to say face 4 of the double glazing, of which only faces 1 and 2 are functionalized as indicated above), reflection on the “exterior” side. of the building (face 1: glass or T1O2) (light transmission and reflection TL and RL in%, chromaticity coordinates a and b * in transmission and reflection on both sides of the glazing, as mentioned previously). The results are shown in the following tables.

Table 111.1: transmission

<td>Glazing n °</td><td>TL</td><td>at'</td><td>b '</td>

<td>3a</td><td> 78,9</td><td> -2,3</td><td> 0,8</td>

<td>3b</td><td> 75,0</td><td> -2,0</td><td> 2,0</td>

<td>3c</td><td> 76,8</td><td> -2,4</td><td> 1,2</td>

<td>3d</td><td> 74,1</td><td> -2,5</td><td> 2,4</td>

Table III.2: interior side reflection

<td>Glazing n °</td><td>RL</td><td>at'</td><td>b</td>

<td>3a</td><td> 12,2</td><td> 0,2</td><td> -2,6</td>

<td>3b</td><td> 15,7</td><td> -1,1</td><td> -5,3</td>

<td>3c</td><td> 14,1</td><td> 0,2</td><td> -3,6</td>

<td>3d</td><td> 16,0</td><td> 0,5</td><td> -6,0</td>

Table III.3: exterior side reflection

<td>Glazing n °</td><td>RL</td><td>at'</td><td>b '</td>

<td>3a</td><td> 11,6</td><td> 0,0</td><td> -5,8</td>

<td>3b</td><td> 16,0</td><td> -1,0</td><td> -8,1</td>

<td>3c</td><td> 13,9</td><td> 0,4</td><td> -6,4</td>

<td>3d</td><td> 15,8</td><td> 0,6</td><td> -8,7</td>

The comparison of glazing 3a and 3b indicates how the addition of the photocatalytic coating is likely to disturb the optical characteristics of the glazing: there is thus a decrease in TL, a substantial increase in RL on both sides, and an increase in chromaticity in reflection on the two sides of the glazing towards the blue-green (negative values ​​of a * and b *).

By glazing 3c, compared to glazing 3b, a portion of lost TL is recovered, it is advantageously again approaching the two RLs of glazing 3a, and its colorimetry values ​​in reflection.

EXAMPLE 4

The methodology of example 3 is repeated for the following glazings (the stacks facing 2 reflect solar radiation, corresponding to average wavelengths of the order of 1 μm). In this example, we denote by X, respectively Y, the anti-solar stack sold by the company Saint-Gobain Glass France under the registered trademark SGG Coollite ST®108, respectively the stack obtained by multiplying the thicknesses of the end layers of this last by 3.7 -proximal side of the glass substrate- and 2/3 -distal side-:

4a: 6 mm glass / X

4b: 18 nm TiO₂/ 150nm SiO₂/ 6 mm glass / X

4c: 18 nm TiO₂/ 50 nm SiO₂/ 12 nm S13N4 / 71 nm SiO₂/ 6 mm glass / X 4d: same photocatalytic stack as 4b / 6 mm glass / Y

In this example and in the following, the glazing is composed of two sheets of glass 6 mm thick between which is interposed an air space 12 mm thick.

The results are shown in the three tables below.

Table IV.1: transmission

<td>Glazing n °</td><td>TL</td><td>at*</td><td>b '</td>

<td>4a</td><td> 6,6</td><td> 2,1</td><td> 6,8</td>

<td>4b</td><td> 6,4</td><td> 2,2</td><td> 7,2</td>

<td>4c</td><td> 6,4</td><td> 2,2</td><td> 6,7</td>

<td>4d</td><td> 8,5</td><td> 1,6</td><td> 6,6</td>

Table IV.2: interior side reflection

<td>Glazing n °</td><td>RL</td><td>at'</td><td>b '</td>

<td>4a</td><td> 34,4</td><td> -2,4</td><td> 13,1</td>

<td>4b</td><td> 34,4</td><td> -2,4</td><td> 13,1</td>

<td>4c</td><td> 34,4</td><td> -2,4</td><td> 13,1</td>

<td>4d</td><td> 28,2</td><td> -1,0</td><td> 13,8</td>

Table IV.3: exterior side reflection

<td>Glazing n °</td><td>RL</td><td>* at</td><td>b '</td>

<td>4a</td><td> 39,4</td><td> -3,0</td><td> 1,9</td>

<td>4b</td><td> 41,5</td><td> -3,0</td><td> 0,4</td>

<td>4c</td><td> 41,3</td><td> -3,1</td><td> 1,8</td>

<td>4d</td><td> 39,4</td><td> -3,1</td><td> 1,9</td>

Here, the TL is little affected by the addition of TiO₂ which also provides a slight decrease in yellow color in reflection on the outside TiO₂ (4b) / glass (4a).

The modification of the anti-solar stack (4d) brings a gain in TL, a substantial decrease in RL on the interior side, accompanied by a slight increase in yellow color in reflection.

EXAMPLE 5

Example 4 is reproduced, X and Y designating here respectively the anti-solar stack marketed by the company Saint-Gobain Glass France under the registered trademark SGG Coollite ST® 120, and the stack differing from the latter only multiplying by 2 the thickness of the proximal layer of the glass substrate:

5a: 6 mm glass / X

5b: 18 nm TiO₂/ 150 nm SiO₂/ 6 mm glass / X

5c: 18 nm TiO₂/ 68 nm SiO₂/ 10 nm S13N4 / 69 nm SiO₂/ 6 mm glass / X 5d: same as 5b / 6 mm glass / Y

Table V.1: transmission

<td>Glazing n °</td><td>TL</td><td>at'</td><td>b '</td>

<td>5a</td><td> 17,2</td><td> -2,3</td><td> -3,9</td>

<td>5b</td><td> 16,5</td><td> -2,2</td><td> -3,2</td>

<td>5c</td><td> 16,8</td><td> -2,3</td><td> -3,9</td>

<td>5d</td><td> 17,0</td><td> -2,2</td><td> -3,9</td>

Table V.2: interior side reflection

<td>Glazing n °</td><td>RL</td><td>at'</td><td>b '</td>

<td>5a</td><td> 29,5</td><td> -0,3</td><td> 13,7</td>

<td>5b</td><td> 29,7</td><td> -0,3</td><td> 13,4</td>

<td>5c</td><td> 29,6</td><td> -0,3</td><td> 13,6</td>

<td>5d</td><td> 31,1</td><td> -0,5</td><td> 12,8</td>

Table V.3: exterior side reflection

<td>Glazing n °</td><td>RL</td><td>at'</td><td>b *</td>

<td>5a</td><td> 32,5</td><td> -1,5</td><td> -1,1</td>

<td>5b</td><td> 34,9</td><td> -1,6</td><td> -2,4</td>

<td>5c</td><td> 33,8</td><td> -1,3</td><td> -1,0</td>

<td>5d</td><td> 32,4</td><td> -1,5</td><td> -1,0</td>

5c compared to 5b shows compared to 5a a partial recovery of the lost TL as well as of the two RLs and, notably, a total recovery of color in reflection on both sides, even with a slightly increased color neutrality.

With 5d, we increase the TL recovered, the reflection on the interior side is slightly higher (worse) while the reflection on the exterior side (TiO₂) is reduced to an even lower level (better) than the RL of 5a on the outside (glass).

EXAMPLE 6

The previous example is reproduced for the following glazings, in which

X and Y respectively denote the anti-solar stack sold by the company Saint-Gobain Glass France under the registered trademark SGG Coollite ST® 136, and the stack differing from the latter only by multiplying the thickness of the proximal layers and distal from the glass substrate by 1.7 and 0.774:

6a: 6 mm glass / X

6b: 18 nmTiO₂/ 150 nm SiO₂/ 6 mm glass / X

6c: 18 nm TiO₂/ 66 nm SiO₂/ 10 nm S13N4 / 57 nm SiO₂/ 6 mm glass / X 6d: same photocatalytic stack as 6b / 6 mm glass / Y

Table VI.1: transmission

<td>Glazing n °</td><td>TL</td><td>-J- at</td><td>b '</td>

<td>6a</td><td> 32,6</td><td> -2,4</td><td> -3,4</td>

<td>6b</td><td> 31,1</td><td> -2,2</td><td> -2,6</td>

<td>6c</td><td> 31,7</td><td> -2,4</td><td> -3,2</td>

<td>6d</td><td> 30,7</td><td> -2,1</td><td> -2,1</td>

Table Vl.2: interior side reflection

<td>Glazing n °</td><td>RL</td><td>at</td><td>b '</td>

<td>6a</td><td> 22,7</td><td> -0,4</td><td> 8,1</td>

<td>6b</td><td> 23,3</td><td> -0,6</td><td> 7,1</td>

<td>6c</td><td> 23,1</td><td> -0,5</td><td> 7,7</td>

<td>6d</td><td> 27,4</td><td> -1,1</td><td> 3,6</td>

Table VI.3: exterior side reflection

<td>Glazing n °</td><td>RL</td><td>at'</td><td>b '</td>

<td>6a</td><td> 21,4</td><td> -1,2</td><td> -6,4</td>

<td>6b</td><td> 24,8</td><td> -1,6</td><td> -7,5</td>

<td>6c</td><td> 23,4</td><td> -1,1</td><td> -6,3</td>

<td>6d</td><td> 21,1</td><td> -1,4</td><td> -6,2</td>

The comparison of 6a and 6b is characterized by an increase in RL on the exterior side of the glazing and, to a lesser extent, by an increase in chromaticity of the second compared to the first.

By optimizing the photocatalytic stack 6c, part of the lost TL is recovered, the RL on the outside side is substantially reduced while recovering the color in reflection on the same face (even with a more neutral colorimetry than 6a).

By modifying the anti-solar stack 6d, the RL on the outside (TiO₂) is lowered to a level still lower than that of 6a on the glass side, and the yellow color component in reflection on the inside of the glazing is weakened compared to that of the other three glazings.

EXAMPLE 7

The previous example is reproduced with the following glazings, in which X and Y denote respectively the anti-solar stack marketed by the company Saint-Gobain Glass France under the registered trademark SGG Coollite ST®150, and the stack not differing from this that by removing the proximal layer of the glass substrate and multiplying the thickness of the intermediate layer by 1.5 and of the distal layer by 0.68:

7a: 6mm glass / X

7b: 18 nm TiO₂/ 150 nm SiO₂/ 6 mm glass / X

7c: 18 nm TiO₂/ 64 nm SiO₂/ 13 nm S13N4 / 50 nm SiO₂/ 6 mm glass / X 7d: same photocatalytic stack as 7b / 6 mm glass / Y

Table VII.1: transmission

<td>Glazing n °</td><td>TL</td><td>at'</td><td>b '</td>

<td>7a</td><td> 45,7</td><td> -2,4</td><td> -1,3</td>

<td>7b</td><td> 43,5</td><td> -2,1</td><td> -0,3</td>

<td>7c</td><td> 44,4</td><td> -2,3</td><td> -1</td>

<td>7d</td><td> 33,4</td><td> -2,1</td><td> -0,4</td>

Table VII.2: interior side reflection

<td>Glazing n °</td><td>RL</td><td>at'</td><td>b '</td>

<td>7a</td><td> 21,4</td><td> -1,0</td><td> 1,5</td>

<td>7b</td><td> 22,6</td><td> -1,3</td><td> 0,4</td>

<td>7c</td><td> 22,1</td><td> -1,1</td><td> 1,1</td>

<td>7d</td><td> 26,0</td><td>-U</td><td> 2,1</td>

Table VII.3: exterior side reflection

<td>Glazing n °</td><td>RL</td><td>at</td><td>b '</td>

<td>7a</td><td> 14,3</td><td> -1,1</td><td> -7,2</td>

<td>7b</td><td> 18,4</td><td> -1,8</td><td> -8,8</td>

<td>7c</td><td> 16,7</td><td> -1,1</td><td> -7,3</td>

<td>7d</td><td> 17,5</td><td> -1,2</td><td> -6,8</td>

Note in particular the quasi-recovery of color in reflection on the exterior side of 7c with respect to 7a.

EXAMPLE 8

This example concerns a so-called “four-season” stack, which is both sunscreen and low-emissive, marketed by the company Saint-Gobain Glass France under the registered trademark Planistar®. Unlike the thermal control stacks of the preceding examples, but like those of the following examples, the latter is not subjected to industrial hardening, which is therefore carried out, if necessary, before its deposition, on the glass sheet optionally provided with its T1O2 coating and the barrier sublayer.

We tested the glazing 5 8a: 6 mm glass / Planistar®

8b: 18 nm T1O2 / 150 nm S1O2 / 6 mm glass / Planistar®

8c: 18 nm TiO₂/ 68 nm SiO₂/ 8nm S13N4 / 58nm SiO₂/ 6 mm glass / Planistar®

Table VIII.1: transmission

<td>Glazing n °</td><td>TL</td><td>at</td><td>b '</td>

<td>8a</td><td> 67,7</td><td> -4,7</td><td> 3,4</td>

<td>8b</td><td> 64,4</td><td> -4,3</td><td> 4,6</td>

<td>8c</td><td> 65,6</td><td> -4,6</td><td> 3,7</td>

Table VIII.2: interior side reflection

<td>Glazing n °</td><td>RL</td><td>+ - at</td><td>b '</td>

<td>8a</td><td> 13,7</td><td> 0,4</td><td> -3,0</td>

<td>8b</td><td> 15,5</td><td> -2,9</td><td> -6,0</td>

<td>8c</td><td> 15,4</td><td> -0,3</td><td> -2,9</td>

Table VIII.3: exterior side reflection

<td>Glazing n °</td><td>RL</td><td>at'</td><td>b '</td>

<td>8a</td><td> 11,1</td><td> -2,6</td><td> -2,6</td>

<td>8b</td><td> 16,3</td><td> -1,2</td><td> -4,2</td>

<td>8c</td><td> 13,9</td><td> -2,3</td><td> -3,2</td>

The glazing 8c, compared to 8b, restores the coloration in reflection on the interior side of 8a, as well as on the exterior side where the decrease in RL relative to 8b is on the other hand a little more significant.

EXAMPLE 9

The thermal control stack is an anti-solar stack marketed by the company Saint-Gobain Glass France under the registered trademark SKN® 154. The glazing 9a: 6 mm glass / SKN® 154 9b: 18 nm TiO is tested₂/ 150 nm SiO₂/ 6 mm glass / ... same as 9a 9c: 18 nm TiO₂/ 68 nm SiO₂/ 8 nm SÎ3N4 / 58 nm SiO₂Z 6 mm glass / same as 9a

Table 1X.1: transmission

<td>Glazing n °</td><td>TL</td><td>at'</td><td>b '</td>

<td>9a</td><td> 49,3</td><td> -7,9</td><td> 2,7</td>

<td>9b</td><td> 47,0</td><td> -7,5</td><td> 3,5</td>

<td>9c</td><td> 47,8</td><td> -7,7</td><td> 3,0</td>

Table IX.2: interior side reflection

<td>Glazing n °</td><td>RL</td><td>at</td><td>b '</td>

<td>9a</td><td> 23,0</td><td> 0,7</td><td> 5,9</td>

<td>9b</td><td> 24,4</td><td> -0,2</td><td> 4,9</td>

<td>9c</td><td> 24,0</td><td> 0,1</td><td> 5,4</td>

Table IX.3: exterior side reflection

<td>Glazing n °</td><td>RL</td><td>at'</td><td>b '</td>

<td>9a</td><td> 19,2</td><td> -3,1</td><td> -9,2</td>

<td>9b</td><td> 22,8</td><td> -3,2</td><td> -9,9</td>

<td>9c</td><td> 21,6</td><td> -2,9</td><td> -9,3</td>

Is particularly evident here, on the exterior side, obtaining with 9c 20 an RL intermediate between that of the other two glazings, and a blue component of the coloration in reflection almost at the same level as in the absence of

TiO₂ (9a).

EXAMPLE 10

The SKN® 165B stack, also marketed by the applicant company, is tested, and more particularly the glazing

10a: 6 mm glass / SKN® 165B

10b: 18 nm TiO₂/ 150 nm SiO₂/ 6 mm glass / ... same as 10a

10c: 18 nm TiO₂/ 69 nm SiO₂/ 9 nm S13N4 / 49 nm SiO₂/ 6 mm glass / ... same as 10a

Table X.1 transmission

<td>Glazing n °</td><td>TL</td><td>-J- at</td><td>b '</td>

<td>10a</td><td> 60,1</td><td> -7,5</td><td> 4,2</td>

<td>10b</td><td> 57,3</td><td> -7,2</td><td> 5,1</td>

<td>10c</td><td> 58,5</td><td> -7,5</td><td> 4,7</td>

Table X.2: interior side reflection

<td>Glazing n °</td><td>RL</td><td>* at</td><td>b *</td>

<td>10a</td><td> 19</td><td> 2,1</td><td> 1,3</td>

<td>10b</td><td> 21,1</td><td> 0,7</td><td> 0,3</td>

<td>10c</td><td> 20,2</td><td> 1,5</td><td> 0,8</td>

Table X.3: exterior side reflection

<td>Glazing n °</td><td>RL</td><td> -_w-—--- at</td><td>b '</td>

<td>10a</td><td> 15,7</td><td> -2,2</td><td> -9,8</td>

<td>10b</td><td> 19,6</td><td> -2,6</td><td> -10,5</td>

<td>10c</td><td> 17,9</td><td> -1,9</td><td> -10,1</td>

EXAMPLE 11

An SiOC barrier layer to the migration of alkalis 50 nm thick covered with a 15 nm layer of TiO is formed on a glass sheet.₂ photocatalytic by a CVD process by reproducing Example 5 of patent EP 0 850 204 B1.

The photocatalytic activity evaluated by photodegradation of stearic acid followed by infrared transmission as above is 9.10 '³cm '¹miri¹, and 7.10 '³cm '¹min¹ after industrial hardening, which corresponds to maintaining the functionality in a large and satisfactory proportion.

Thus, the invention makes available the possibility of preparing glazing with hardenable anti-fouling photocatalytic coatings and high activity, under the best industrial conditions, with levels of light transmission and reflection and colorimetry characteristics in transmission and in color. reflection easily adjustable to the values ​​sought by the user.