WO2025021552A1 - Sun-protection multiple glazing comprising a coating with infrared reflection properties and an anti-reflective coating - Google Patents

Abstract

Multiple glazing with thermal insulation properties, having a first coating (12) with an infrared-reflection property and a second coating (13) with an anti-reflective property, wherein the first coating is present on face 2 of the first substrate, and wherein the second coating (13) is deposited on face 2 of the first substrate between the glass surface and the first coating.

Description

DESCRIPTION

Title: MULTIPLE SOLAR-PROOF GLAZING COMPRISING A COATING WITH INFRARED REFLECTION PROPERTIES AND AN ANTI-REFLECTIVE COATING

The invention relates to multiple glazing, in particular double glazing or triple glazing for the building sector, said glazing comprising a functional layer of metallic type capable of acting on solar radiation and in particular solar infrared radiation, in particular with a wavelength between 780 nm and 5000 nm.

The invention relates more particularly to multiple glazings with infrared reflection properties, often called in the field antisolar glazings, and having a low solar factor.

These windows are therefore intended to equip buildings in particular, in particular with a view to limiting the solar energy input entering them.

In such multiple glazings, for example double glazing, two glass substrates are held at a distance by spacers, so as to delimit a cavity filled with an insulating gas which can be air, argon or Krypton. Double glazing is therefore made up of two sheets (substrates) of glass separated by a gas layer. The sequence 4/16/4 thus designates a double glazing composed of two sheets of glass 4 mm thick and a 16 mm air layer as shown in Figure 1 attached.

Conventionally, the faces of a multiple glazing unit are designated from the outside of the building. For example, a double glazing unit has 4 faces, face 1 being on the outside of the building (and therefore constitutes the external wall of the glazing), face 4 on the inside of the building (and therefore constitutes the internal wall of the glazing), faces 2 and 3 being on the inside of the double glazing unit.

Similarly, a triple glazing unit has 6 faces, face 1 is on the outside of the building (outer wall of the glazing), face 6 is on the inside of the building (inner wall of the glazing) and faces 2 to 5 are on the inside of the triple glazing, as shown in Figure 2 attached. As is known, thermally insulating double glazing (often also called double glazing (DGU for Double Glazing Unit according to the English term) or triple glazing TGU (for Triple Glazing Unit)) comprises a stack of layers incorporating at least one functional metal layer, i.e. with a property of reflecting solar infrared, in particular at least one functional metal layer based on silver or a metal alloy containing silver, and most often a plurality of such metal layers, for example 2 or 3 silver layers separated by layers of dielectric materials. By infrared reflection property, it is meant that at least a portion of the solar infrared radiation, preferably the major portion, is reflected by the stack via its functional layer(s), without excluding another portion being absorbed by it.

This stack is traditionally placed on face 2 of the double glazing in such anti-solar glazing for maximum efficiency.

Examples of multiple glazings equipped with such silver layers are for example described in publications WO 2007/101964, EP877005, EP718250, FR2856627, EP 847965, EP 183052, EP226993, EP2920126,

EP2766318, EP1441996, EP2432745, EP2424823, EP2332891, EP1730088,

EP1663887, EP1606225, EP3041676, US10556824, EP1458653 or even

EP3004012.

Although the functional metal layer(s) is (are) preferably silver-based, other metal layers can also be envisaged without departing from the scope of the invention, in particular based on precious metals such as Au, Pt, or even based on Ni, Cr, NiCr, Nb, Ti, the latter being able to be nitrided.

Currently, such a stack of layers is previously deposited on one of the glass substrates of the multiple glazing in the same installation for depositing layers by magnetic field-assisted cathodic sputtering from targets made of the material to be deposited or from a metal target, for example silver, or a constituent element of the layer such as silicon or titanium in a reactive atmosphere of oxygen or nitrogen, to obtain a final layer of a dielectric material. such as silicon oxide or silicon nitride. Such a process is called in the field of “magnetron” deposition process.

A parameter for measuring the quality of multiple glazing with an antisolar function is the solar factor FS or g factor. It is defined as the ratio between the energy entering the room through the glazing and the incident solar energy. It can be calculated by the sum of the energy flow transmitted directly through the glazing and the energy flow absorbed and then re-emitted to the interior by the glazing. The FS coefficient (g) can be measured according to standard EN 410 (2011-04).

In addition, in the construction industry, glazing is sought with a high level of light transmission (i.e. in the visible range) but which can be variable, in particular from 50 to 85%. In order to be able to compare the performance of different glazings, it is therefore common to also refer to the selectivity of the glazing in question, i.e. its TL/g ratio. Thus, better (greater) selectivity makes it possible to check the good illumination of the room, without excessive heating of the latter under the effect of incident solar radiation, in particular its infrared portion.

In countries with high levels of sunshine, it is always necessary to improve the performance of the multiple insulating glazing described above and in particular their selectivity, for the same level of light transmission.

The object of the present invention is to provide multiple anti-solar glazings comprising a stack of layers incorporating at least one functional metal layer with infrared reflection properties as described above and whose solar factor and consequently selectivity are improved.

For this purpose, the present invention relates more particularly to a multiple glazing with thermal insulation properties, obtained by the association of at least two glass substrates separated by a gas layer, the front face of the first substrate defining the outer wall of the glazing, the successive faces of said two substrates being numbered from 1 to 4 from the outside to the inside of said glazing. The multiple glazing incorporates a) a first coating with infrared reflection property consisting of a stack of layers preferably comprising at least one silver-based metallic functional layer and b) a second coating with anti-reflective property of visible light consisting of a layer of a material with a refractive index at 550 nm lower than that of glass or consisting of a stack of layers, including at least one layer of a material with a refractive index at 550 nm lower than that of glass, preferably less than 1.4, or even less than 1.35.

In the multiple glazing according to the invention, said first coating is present on face 2 of said first substrate and said second coating is also deposited on face 2 of the first substrate between the glass surface and said first coating.

In a unique way, it was found that the combination of these two coatings, one with infrared reflection properties and the other with anti-reflective properties, made it possible to offer multiple glazings with improved solar factor and selectivity, for the same target light transmission.

It is known that the level of reflection of a transparent glass surface is mainly determined by the contrast of the refractive index existing between the surface and that of air (equal to 1). To obtain antireflective properties from a reflective surface, it is also known to deposit a transparent layer (here called antireflective coating or with antireflective property) which provides a specific optical behavior, in which the reflected light waves are in phase opposition with the incident waves when the reflection occurs on the air/coating interface and on the coating/glass interface. This type of coating is called single-layer antireflective coating.

By anti-reflective coating, we mean any coating capable of reducing the reflection of visible light (i.e. of wavelength between 380 and 780 nm) on a glass surface, in particular by at least 1%, or even 2%, or even 3% (i.e. reducing an initial reflection of visible light from 4% to 3, 2 or even 1%).

The light transmission and reflection on the surface of a glass substrate on which such a coating is deposited can be measured according to standard EN 410 (2011-04). There are various possibilities for forming the antireflective coatings according to the invention, in particular porous silica layers. These layers can be nanoporous, mesoporous or even macroporous.

These coatings are characterized by the presence of a certain amount of air trapped in the porosity. The porosity is created by the imperfect compactness of the nanoparticles, by the elimination of porogens such as PMMA beads present within the silica layer and then eliminated by heating or by acid/alkaline attack. Such coatings are described for example in the following publications: Chen et al., Journal of Sol-Gel Science and Technology 19, 77-82, 2000; Kocs et al. Ceramics International 48 (2022) 4165- 4171; Zheng et al., Ceramics International 46 (2020) 18623-18631 or Yoo et al., Vol. 9, No. 11 / 1 November 2019 / Optical Materials Express or patent publications WO2013024226 or EP1679291.

There are currently several techniques for having porous layers, in particular through the use of porogens:

- Either by using a sacrificial organic porogen which burns on quenching, as indicated previously,

- Either by using a “durable” porogen, such as a hollow nanometric bead, in which case heat treatment is not necessary.

Without departing from the scope of the invention, it is also possible to use antireflection layers other than the porous silica type, in particular acrylates crosslinkable under the action of radiation. Preferably, the porosity is not present on the surface for such coatings, the surface is therefore very smooth. According to another alternative, it is also possible to use according to the invention an antireflection coating consisting of a stack of layers of different refractive index (generally an alternation of layers of high/low refractive index) in order to obtain a phase shift of the reflected light waves. This type of product is called a multilayer or interference antireflection coating. These coatings are generally developed to obtain very high-performance antireflection properties over a wider range of wavelengths. An example of this is given by publication WO2012069767. By “stack” for the purposes of the present invention, it is necessary to understand a set of at least two superimposed layers, starting from the surface of a glass substrate.

For the first infrared-reflecting stack comprising at least one metallic functional layer, stacks leading to a normal emissivity s _n less than or equal to 0.2, preferably less than or equal to 0.1, more preferably less than or equal to 0.08, or even very advantageously less than or equal to 0.05, within the meaning of standard EN12898 (2001-07) will advantageously be chosen.

For the purposes of the invention, “in contact” means that no other intermediate layer is interposed between the two layers mentioned.

According to preferred embodiments of such multiple glazings, which can of course be combined with each other, if necessary:

- said second coating consists of a single layer comprising silicon oxide with a refractive index of less than 1.40 at 550 nm, preferably with a refractive index of less than 1.35 at 550 nm,

- said layer comprises porous silicon oxide, in particular nanoporous, mesoporous or macroporous,

- the physical thickness of said single layer present on face 3 is between 90 nm and 150 nm,

- the thickness of said single layer present on face 2 is between 90 nm and 400 nm,

- the light transmission of the glazing is between 45 and 85%, preferably between 60 and 80%,

- according to a first method, the glazing comprises only one coating with anti-reflective properties,

- according to another embodiment, the glazing comprises a coating with anti-reflective properties deposited on face 3 of the second substrate and a coating with anti-reflective properties deposited on face 2 of the first substrate, between the glass surface and said first coating. - other coatings with anti-reflective properties, in particular consisting of so-called interference stacks, can be incorporated on the external faces of the glazing (i.e. on face 1 and/or 4 of a DGU and on faces 1 and 6 of the TGU).

The invention relates in particular to double glazing obtained by combining two glass substrates separated by a gas layer, in which said first coating is present on face 2 of said first substrate, and in which said second coating is deposited on face 2 of the first substrate between the glass surface and said first coating.

According to particular and advantageous modes of such double glazing:

- said first coating is present on face 2 of said first substrate and a single second coating is deposited on face 2 of the second substrate, between the glass surface and said first coating,

- said first coating is present on face 2 of said first substrate, a first second coating is deposited on face 3 of the second substrate and a second second coating is deposited on face 2 of the first substrate between the glass surface and said first coating.

The invention also relates to triple glazing with thermal insulation properties, obtained by combining three glass substrates separated by gas layers, the first substrate delimiting faces 1 and 2 of the glazing, the second substrate delimiting faces 3 and 4 of the glazing, said third substrate delimiting faces 5 and 6 of the glazing, in which said first coating is present on face 2 of said first substrate, and in which said second coating is deposited on face 2 of the first substrate between the glass surface and said first coating.

According to particular and advantageous modes of such triple glazing:

- a single second anti-reflective coating is deposited on face 2 of the first substrate between the glass surface and said first coating with infrared reflection properties,

- a first second anti-reflective coating is deposited on face 2 of the second substrate and a second second anti-reflective coating is deposited on the face é of the first substrate between the glass surface and said first coating,

- a first second anti-reflective coating is deposited on face 2 of the second substrate and a second second anti-reflective coating is deposited on face 4 of said second substrate.

The details and advantageous characteristics of the invention emerge from the following non-limiting examples, illustrated using the attached figures which schematize different embodiments of multiple glazing according to the present invention:

- Figure 1 describes double glazing according to a first embodiment of the invention,

- Figure 2 describes triple glazing according to a second embodiment of the invention.

In these figures, the actual dimensions and proportions of the various constituent elements of the glazing are obviously not respected in order to facilitate their reading.

Figure 1 shows a double glazing unit 100 (DGU) of conventional design consisting of two sheets of glass, each constituting a glass substrate 10, 30. The two substrates are separated, held together and facing each other by spacers 21 and frames 20, the assembly delimiting an enclosed space filled by an intermediate gas layer 15. According to the invention, the gas may be air, argon or Krypton (or a mixture of these gases).

The first glass sheet (substrate 30) faces outwards when considering the incident direction of the sunlight entering the building, illustrated by the arrow oriented in the figure from left to right. Its front face 29 (called “face 1”), which also constitutes the outer wall of the double glazing 100, may be bare or alternatively be coated with another coating of the self-cleaning type as described in publication EP 850204 or of the anti-condensation type, as described in publications W02007/115796 or W02009/106864.

The substrate 30 is coated on its rear face 31 (face 2 of the DGU), facing the intermediate gas blade 15, by a coating 12 with reflective properties. infrared because it reflects a major part of the infrared portion of the incident radiation, in particular from 780 nanometers to 5000 nanometers. This stack is of the type described above, and preferably comprises at least one layer of silver, preferably two or three layers of silver.

The other sheet of glass, oriented furthest inside the building when considering the incident direction of the sunlight entering it, constitutes the second substrate 10. According to the invention and as shown in FIG. 1, an anti-reflective coating 13 of the type previously described and in particular consisting of a layer of porous silicon oxide, with a refractive index at 550 nm lower than that of the glass, in particular of the order of 1.33, is also deposited on the face 2 of the DGU, between the surface 31 of the substrate 30 and the infrared-reflecting stack 12.

According to another embodiment of the present invention, it is advantageous to arrange two coatings with an infrared reflection function in the manner previously described respectively on faces 2 and 3 of the DGU, as described in the examples which follow.

Figure 2 this time represents a triple glazing 101 (TGU) of classic design consisting of three sheets of glass, each constituting a glass substrate 30, 10 and 40. Identical numbers are taken from Figure 1 to illustrate the same constituent elements.

As previously, the substrate 30 is coated on its rear face 31 (face 2 of the DGU), facing the intermediate gas blade 15, with a coating 12 with infrared reflection properties.

According to an embodiment of the invention illustrated by FIG. 2, an antireflection coating 13 of the type previously described and in particular consisting of a layer of porous silicon oxide, is arranged on the face 2 of the TGU, between the surface 31 of the substrate 30 and the stack with infrared reflection property 12. Another antireflection coating 13' can also be deposited on the face 32 of the intermediate substrate 10 (i.e. on the face 3) of the TGU. According to the invention, it is also possible to arrange an additional antireflection coating on the face 4 of the TGU, in particular on the surface 32 of the substrate 10 or on the face 5 of the TGU, i.e. on the surface 33 of the substrate 10. The invention and its advantages will be better understood upon reading the non-limiting examples which follow.

In all the examples below, the thin-film stacks with low-emissivity properties are deposited on clear soda-lime glass substrates, marketed under the reference PLANICLEAR® by the applicant company. For all the examples below, for double-glazing or triple-glazing assemblies, the thin-film stacks were positioned respectively on face 2 and/or 3, the numbering increasing starting from the glass substrate furthest to the outside of the building when considering the incident direction of the sunlight entering the building, face 1 therefore corresponding to the glass surface facing the outside of the glazing. The double and triple glazing described in the examples below are in accordance with figures 1 and 2 attached.

The double glazing units (or DGU for Double Glazing Unit) assembled according to the examples have the configuration: 4-16-(Ar 90%)-4, that is to say they are made up of two transparent 4 mm Planiclear® glass sheets separated by an intermediate gas layer comprising 90% argon and 10% air by volume, with a thickness of 16 mm, the whole being held together by a frame structure 20 and spacers 21.

The triple glazing (or TGU or DGU for Double Glazing Unit) assembled according to the examples has the configuration: 4-16-(Ar 90%)-4-16-(Ar 90%)-4.

Table 1 below summarizes the general conditions for magnetron sputtering deposition to obtain the different layers used in the infrared reflection stacks of the examples:

[Table 1]

The anti-reflective coating consists of a single layer based on porous silicon oxide whose porosity is adjusted to obtain a layer of material with a refractive index of 1.33 at 550 nm.

Example 1:

In this first series of examples, we compare DGU double glazing with a target light transmission of 68.5%.

The double glazing has a 4/16/4 configuration as described previously.

This first example illustrates the case of a combination of a coating with infrared reflection properties deposited on face 2 by magnetron sputtering and the porous silica anti-reflective layer described previously (index 1.33) on face 2 or on face 3 or on both faces.

More precisely, the glazing according to example 1a is a reference glazing having a light transmission of 68.5% and comprising on its face 2 a stack with infrared reflection properties comprising two functional silver layers and the complete structure of which is described in table 3 below.

In example 1b, an anti-reflective monolayer of porous silica is positioned on face 2 of the DGU, between the glass surface and the stack with infrared reflection properties, with a thickness of 115 nm and a refractive index of 1.33 at 550 nm.

The infrared reflecting stack is then adjusted to obtain a light transmission of 68.5% (in particular by modifying the thicknesses of the silver layers), as described in Table 3 below.

In example 1c, two anti-reflective layers of the same index as previously are positioned on faces 2 and 3 of the DGU, with thicknesses of 103.5 nm and 100 nm respectively. The anti-solar stack (in particular the thicknesses of the silver layers) is then adjusted to obtain a final light transmission of 68.5% respectively.

In example 1d, comparative to example 1b, a porous silica antireflection monolayer is positioned on face 3 of the DGU, with a thickness of 115 nm and a refractive index of 1.33 at 550 nm. Example 1d differs from example 1b in that the antireflection layer is on face 3 and not on face 2.

The results are reported in Table 2 below: [Table 2]

In the previous table, TL is the light transmission, a*T and b”T are the colorimetric coordinates in the international Lab system, TE is the energy transmission and RL _ex t and RL _in t are the light reflections respectively on the exterior and interior sides of the double glazing.

The thicknesses in nanometers of the different layers constituting the stacks with infrared reflection properties for examples 1a to 1d are given in table 3 below (the one furthest from the surface of the glass substrate being referenced first):

[Table 3]

It can be seen by comparing the above examples that the selectivity obtained in the case of a stack with infrared reflection property deposited on face 2 is significantly improved by the addition of an anti-reflective layer on face 2 of the double glazing.

In particular, the deposition of the antireflection layer on face 2 and the adjustment accordingly of the structure of the stack a with infrared reflection property results in a significant reduction in the solar factor g and consequently in a significant improvement in selectivity. For example, it can be observed that, for the same TL of 68.5%, the addition of the antireflection layer on face 2 between the glass surface and the stack with infrared reflection property, combined with the adjustment of this stack, results in a 5.2% reduction in the factor g (comparison of examples 1a and 1b). The gain can be even more significant (7.1% reduction in g) if two antireflection stacks, on faces 2 and 3, are combined with the stack with infrared reflection property within the DGU (comparison of examples 1a and 1c). It is also noted that the glazing according to comparative example 1d, in which the anti-reflective layer is this time placed on face 3 of the glazing, does not allow a similar reduction in the factor g.

Example 2:

In this second series of examples, we compare DGU double glazing with a target light transmission of 77%. Like the previous one, this example illustrates the case of a combination of a coating with infrared reflection properties deposited on face 2 by magnetron sputtering and the anti-reflective layer described previously (index 1.33) on face 2 and on face 3.

More precisely, the glazing according to example 2a is a reference glazing having a higher light transmission equal to 77% and comprising on its face 2 a stack with infrared reflection properties comprising two functional silver layers and the complete structure of which is described in table 5 below.

In example 2b, two antireflective layers of the same index as previously are positioned on faces 2 and 3 of the DGU, with thicknesses of 103.5 nm and 100 nm respectively. The anti-solar stack (in particular the thicknesses of the silver layers) is then adjusted to obtain a final transmission of 77.0% respectively.

The results are reported in Table 4 below: [Table 4]

The thicknesses in nanometers of the different layers constituting the stacks with infrared reflection properties for examples 2a and 2b are given in table 5 below (the one furthest from the surface of the glass substrate being referenced first):

[Table 5]

It can be seen by comparing the above examples that the selectivity obtained in the case of a stack with infrared reflection properties deposited on face 2 is significantly improved by the addition of anti-reflective layers on faces 2 and face 3 of the double glazing.

In particular, the deposition of antireflection layers on faces 2 and 3 and the adjustment accordingly of the structure of the stack with infrared reflection property results in a significant reduction in the solar factor g and consequently in a significant improvement in selectivity. For example, it is observed that, for the same TL of 77%, the addition of the antireflection layer on face 3 and the adjustment of the stack with infrared reflection property results in a reduction of 11.3% in the factor g (comparison of examples 2a and 2b).

Example 3:

In this third series of examples, TGU triple glazing units with a target light transmission of 68.5% are described. The triple glazing units have a 4/16/4/16/4 configuration as previously described.

More precisely, the glazing according to example 3a is a reference TGU comprising on its face 2 a stack with reflection properties of infrared comprising two functional silver layers and whose complete structure is described in Table 7 below.

In example 3b, two anti-reflective layers of porous silica with a refractive index of 1.33 are positioned on faces 2 and 3 of the TGU, respectively, with respective thicknesses of 332 nm and 99 nm.

The anti-solar stack (in particular the thicknesses of the silver layers) is adjusted to obtain a final target light transmission of 68.5.

The results are reported in Table 6 below:

[Table 6]

The thicknesses in nanometers of the different layers constituting the stacks with infrared reflection properties for examples 3a and 3b are given in table 7 below (the furthest from the surface of the glass substrate being referenced first): [Table 7]

We also observe that, for the same TL of 68.5%, the addition of anti-reflective layers on faces 2 and 3 and the adjustment of the stack to infrared reflection properties results in a 9.5% reduction in the g factor (comparison of examples 3a and 3b).

Claims

1. Multiple glazing with thermal insulation properties, obtained by combining at least two glass substrates (10, 30) separated by a gas layer (15), the front face (29) of the first substrate (30) defining the outer wall of the glazing, the successive faces of said two substrates being numbered from 1 to 4 from the outside to the inside of said glazing, said multiple glazing incorporating: - a first coating (12) with infrared reflection properties consisting of a stack of layers, said stack preferably comprising at least one silver-based metal layer, - a second coating (13) with anti-reflective properties consisting of a layer of a material with a refractive index of 550 nm lower than that of the glass or consisting of a stack of layers, including at least one layer of a material with a refractive index of 550 nm lower than that of the glass, in which said first coating (12) is present on face 2 of said first substrate, and in which said second coating (13) is deposited on face 2 of the first substrate, between the glass surface and said first coating. 2. Multiple glazing according to claim 1, in which said second coating consists of a single layer comprising silicon oxide with a refractive index of less than 1.40 at 550 nm, preferably with a refractive index of less than 1.35 at 550 nm. 3. Multiple glazing according to the preceding claim, in which said layer comprises porous silicon oxide, in particular nanoporous, mesoporous or macroporous. 4. Multiple glazing according to one of the preceding claims in which the thickness of said single layer present on face 2 is between 90 nm and 400 nm, preferably between 90 and 200 nm. 5. Multiple glazing according to one of the preceding claims, in which the light transmission is between 45 and 85%, preferably between 60 and 80%. 6. Multiple glazing according to one of the preceding claims, comprising only one coating with anti-reflective properties. 7. Multiple glazing according to one of claims 1 to 6, in which an additional anti-reflective coating is deposited on face 3 of the second substrate, preferably with a thickness of between 90 nm and 400 nm, more preferably between 90 and 200 nm. 8. Double glazing according to one of the preceding claims, obtained by the association of two glass substrates (10, 30) separated by a gas blade (15), in which said first coating is present on face 2 of said first substrate, and in which said second coating (13) is deposited on face 2 of the first substrate between the glass surface and said first coating. 9. Double glazing according to claim 8, wherein said first coating is present on face 2 of said first substrate, wherein a second second coating (13) is deposited on face 2 of the first substrate between the glass surface and said first coating and wherein an additional anti-reflective coating (13') is deposited on face 3 of the second substrate (10). 10. Triple glazing with thermal insulation properties according to one of claims 1 to 7, obtained by the combination of three glass substrates separated by gas blades, the first substrate delimiting faces 1 and 2 of the glazing, the second substrate delimiting faces 3 and 4 of the glazing, said third substrate delimiting faces 5 and 6 of the glazing, in which said first coating is present on face 2 of said first substrate, and in which said second coating (13) is deposited on face 2 of the first substrate between the glass surface and said first coating. 11. Triple glazing according to one of the preceding claims, in which a coating (13') with additional anti-reflective properties is deposited on the face 3 of the second substrate (10).