CN114391005A

CN114391005A - Insulating glazing comprising a thin chromium-based layer

Info

Publication number: CN114391005A
Application number: CN202080064908.2A
Authority: CN
Inventors: R·阿吉亚; S·阿巴迪
Original assignee: Saint Gobain Glass France SAS
Current assignee: Saint Gobain Glass France SAS
Priority date: 2019-09-20
Filing date: 2020-09-18
Publication date: 2022-04-22
Also published as: BR112022000923A2; EP4031506A1; CO2022001910A2; WO2021053125A1; MX2022003313A; AU2020349035A1; FR3101077A1; FR3101077B1

Abstract

A transparent glass article comprising at least one glass substrate provided on at least one of its faces with a coating consisting of a stack of thin layers, at least one functional layer of the stack imparting solar control properties to the article, the coating comprising the following sequence of layers, with reference to the surface of the substrate: a first layer comprising silicon nitride, a functional layer based on metallic chromium having a physical thickness greater than or equal to 1nm and less than or equal to 9nm, preferably greater than or equal to 2nm and less than or equal to 8nm, a second layer comprising silicon nitride, wherein said first and second layers comprising silicon nitride are in direct contact with the functional layer based on metallic chromium.

Description

Insulating glazing comprising a thin chromium-based layer

The present invention relates to an insulating glazing, known as a "solar control glazing", provided with a stack of thin layers, at least one of which is functional, that is to say it relates to the action of solar radiation and/or thermal radiation, mainly by reflection and/or absorption of near infrared (solar) or far infrared (thermal) radiation. The invention relates more particularly to multiple glazing, particularly those intended primarily for the thermal insulation of buildings.

The expression "functional" or "active" layer is understood in the sense of the present application to mean the layer of the stack that imparts the majority of the thermal properties to the stack. Most often, the glazing-equipped thin-layer stack imparts improved solar control properties to the active layer, primarily through its inherent properties. In contrast to other layers, which are generally made of dielectric materials and essentially have the function of chemically or mechanically protecting the functional layer or of adjusting the color, the layers act on the solar radiation flux passing through the glazing.

Such glazing provided with a stack of thin layers acts on the incident solar radiation mainly by absorption of the incident radiation by the functional layer or mainly by reflection of the same layer.

They are classified under the name solar control glazing. They are sold and used for essentially the following purposes:

or to ensure mainly the protection of the house from solar radiation and to prevent it from overheating, such glazing being characterised in the field of solar protection,

or mainly for ensuring the insulation of houses and preventing heat losses, these glazings being characterised as insulating glazings.

The term "solar protection" is therefore understood in the context of the present invention to mean the ability of a glazing to limit the energy flux, in particular the solar Infrared Radiation (IRS) passing through it from the outside to the inside of a house or passenger cabin.

To measure the energy insulating properties of a glazing, a solar factor is used in the field, denoted SF or g in this field.

As is well known, the solar factor g is equal to the ratio of the energy passing through the glazing (i.e. into the space) to the incident solar energy. More specifically, it corresponds to the sum of the flux transmitted directly through the glazing and the flux absorbed by the glazing (including the stack of layers optionally present on one of its surfaces) and then possibly re-emitted towards the interior (room).

Therefore, good thermal insulation properties require, above all, a low electrical resistivity of the functional layer. However, this property is also manifested in a higher light absorption, which tends to significantly reduce the light transmission within the glazing. The object of the present invention is firstly to provide a glazing equipped with a stack which exhibits a good compromise between its light transmission and thermal insulation properties.

In general, all the light characteristics presented in this description, in particular the light transmission T_LAnd light reflection R_LAnd factor g, obtained according to the principles and methods described in standard NF EN 410(2011) in connection with the determination of the light and energy characteristics of glazings used in architectural glazing.

Ideally, such a glazing should have a substantially neutral colour in both transmission and reflection, whether on the face of the glazing on which the stack is deposited (the inner side) or on the opposite face (the outer side).

The best performing layer stacks currently marketed comprise at least one metallic layer of silver type, which essentially operates in a mode reflecting most of the incident IR (infrared) radiation. Therefore, these stacks are mainly used as low-emissivity (or low-emission) type glazing for the insulation of buildings. However, these layers are very sensitive to moisture and are therefore used exclusively inside the double glazing (on its 2 nd or 3 rd side) to protect against moisture. It is therefore not possible to deposit such a layer on a simple glazing (also known as a monolithic glazing). The stack according to the invention does not comprise such silver-based layers, or gold-or platinum-based layers, or they are present in very negligible amounts, in particular in the form of unavoidable impurities.

Also, the functional layers, even the stack, of the glass article according to the invention do not contain nickel or copper.

The disadvantage of silver-based layers is also their poor mechanical strength, which also explains their use in the construction field almost exclusively for the inner faces of multiple glazing (for example faces 2 and 3 of double glazing).

Other metal layers with a sunscreen function are also reported in the art, including functional layers of the Nb or niobium nitride NbN type, as described for example in application WO01/21540 or in application WO 2009/112759. Within these layers, solar radiation is now absorbed non-selectively mainly by the functional layer comprising niobium, and IR radiation (i.e. having a wavelength between about 780nm and 2500 nm) and visible radiation (having a wavelength between about 380-780 nm) are absorbed indiscriminately by the active layer.

In addition to sun protection, in the building and even automotive field, there is sometimes a need for privacy glazing, i.e. glazing that allows the occupants of a room, building or vehicle to easily look from the inside outwards during the day, but presents a specular appearance (obstructing the view in that direction) from the outside inwards. However, in night vision, i.e. when the external brightness is greater than the internal brightness, such a glazing may present the drawback of presenting the same specular effect from the outside towards the inside this time if the internal reflection is too great.

In order to solve such problems, it is necessary to propose a glass article having suitable light emission characteristics.

In particular, the above problems can be solved according to the invention by developing a glass article which:

-a light transmission of greater than or equal to 20%,

light reflection R at one side of the glass (outer face)_LextGreater than or equal to 25%, or even greater than or equal to 30%,

light reflection R at one side (inner face) of the stack_LintLess than or equal to 20%, even less than or equal to 15%,

the difference R between the two light reflections_Lext-R_Lint(in the rest of the description also denoted as Δ R_L) Greater than 15%, or even greater than 18%, or even greater than 20%.

The term "on one side of the stack" is understood to mean the face of the glazing on which the stack is deposited. The term "on the glass side" is understood to mean the face of the glazing opposite to the face on which the stack is deposited, which face is in principle not covered. Within the meaning of the present invention, the terms "exterior face" (or "outer face") and "interior face" (or "inner face") refer to the position of the glazing when it is fitted to a building or equipped vehicle.

Also, the glass articles and glazings according to the present invention have solar factor g approaching and preferably less than 50%, even less than 45% or even less than 40% in certain configurations, in accordance with the energy insulating properties required in the art.

The object of the present invention is to propose a glass product which allows to solve the above technical problems.

More precisely, the invention relates to a transparent glass article comprising at least one glass substrate provided on at least one of its faces with a coating consisting of a stack of thin layers, at least one functional layer of which confers to said article solar control properties, said coating comprising the following sequence of layers, with reference to the surface of said substrate:

-a first layer comprising silicon nitride,

-a functional layer based on metallic chromium having a physical thickness greater than or equal to 1nm and less than or equal to 9nm, preferably greater than or equal to 2nm and less than or equal to 8nm,

-a second layer comprising silicon nitride,

wherein the first and second layers comprising silicon nitride are in direct contact with a metallic chromium-based functional layer.

According to particular and preferred embodiments of the invention, they can be combined with one another, if desired:

the first layer comprising silicon nitride has a thickness of 1-100nm, preferably 10-80 nm.

The second layer comprising silicon nitride has a thickness of 1-100nm, preferably 1-50nm, more preferably 2-25 nm.

-the first layer comprising silicon nitride is thicker than the second layer comprising silicon nitride.

The stack does not comprise any layer based on Ag, Au, Pt, Cu, Ni or stainless steel.

The stack comprises a single functional layer based on metallic chromium, the thickness of which is 2-9nm, in particular 3-8 nm.

The stack consists of a sequence of the following layers:

SiN_x/Cr/SiN_x

wherein SiN_xDenotes that the layer comprising silicon nitride and Cr denotes the metallic chromium-based layer.

The stack comprises two chromium-based functional layers, a third layer comprising silicon nitride being interposed in the stack between the two chromium-based functional layers.

-the third chromium layer is in direct contact with the chromium-based layer according to the following sequence of layers:

SiN_x/Cr/SiN_x/Cr/SiN_x

wherein SiN_xRepresents said layer comprising silicon nitride and Cr represents said layer based on metallic chromium.

In particular, the value of x may deviate from the value corresponding to the definition of Si in the sense of superstoichiometric nitrogen or, preferably, substoichiometric nitrogen₃N₄Even if in principle it does not differ by more than 20% from the theoretical value, the conventional value of the compound of (x = 1.33).

-the chromium-based functional layer comprises more than 80% by atoms of chromium.

-said one or more functional layers, apart from unavoidable impurities, consist essentially of chromium, preferably of chromium.

A first layer comprising silicon nitride is deposited directly on and in contact with the glass substrate.

Between the surface of the glass substrate and the first layer comprising silicon nitride there is at least one layer comprising a metal oxide, preferably selected from the oxides of one element selected from silicon, titanium, tin, zinc, aluminium, zirconium or of a mixture of at least two of these elements, in particular silicon oxide, titanium oxide or zinc tin oxide.

Above said layer sequence there is at least one layer comprising a metal oxide, preferably selected from the oxides of one element selected from silicon, titanium, tin, zinc, aluminum or the oxides of a mixture of at least two of these elements, in particular silicon oxide, titanium oxide, zirconium oxide or a mixture of these oxides.

-the article is subjected to thermal quenching and/or bending.

The one or more chromium-based functional layers comprise at least 50 atomic% chromium. Preferably, the functional layer or layers of the layer stack have at least 70% atomic, even at least 80% atomic, or even preferably more than 90% atomic, chromium.

According to a very preferred embodiment, said one or more functional layers consist essentially of chromium, more preferably of chromium, with the exception of unavoidable impurities.

However, the one or more functional layers may comprise one or more further atoms, for example selected from Al, Si, Mo, W, Zn, Ti, Mg, Co, Ni, without departing from the invention.

The chromium content and the content of other elements optionally present can be measured according to any known technique. For example, XPS (X-ray photoelectron spectroscopy) may be mentioned.

The functional layer or layers according to the invention may contain a minimum fraction of nitrogen and/or oxygen, but less than 15% atomic, or even less than 10% atomic, or even less than 5% atomic. Preferably, however, the functional layer or layers according to the invention in principle do not contain nitrogen or oxygen, or are then in the form of unavoidable impurities, for example as a result of heat treatment, such as quenching or bending, of the glazing.

Likewise, the functional layer or layers according to the invention in principle contain no carbon or hydrogen, or are in the form of unavoidable impurities.

In the layer comprising silicon nitride according to the invention, silicon nitride preferably represents at least 50% by weight of silicon nitride, based on Si₃N₄Formulations, preferably more than 80% silicon nitride or even more than 90% silicon nitride, based on Si₃N₄And (4) preparing. The layer preferably consists essentially of silicon nitride, but may also comprise elements other than silicon, in particular aluminum. In particular aluminum is commonly used in silicon targets for the deposition of thin-layer stacks, in particular silicon nitride-based layers, by magnetic field enhanced (magnetron) cathodic sputtering on solar control glazing in proportions of up to 15% by atoms. Thus, according to techniques well known in the art and up to 15% original, without departing from the scope of the inventionIn sub-proportions, the silicon of said layer may be replaced by elements of the Al, Zr, B, etc. type, in particular to modify the colour of the glazing in transmission and/or reflection.

The coating according to the invention is generally deposited by a deposition technique of the magnetic field enhanced vacuum cathode sputtering type of the material or of a precursor of the material to be deposited, commonly known in the art as magnetron sputtering technique. This technique is commonly used today, in particular when the coating to be deposited consists of a more complex continuous stack of layers with a thickness of a few nanometers or a few tens of nanometers.

The invention also relates to an exterior cladding panel of the basement wall type comprising at least one glazing as described above, or to a side window, rear window or roof of a motor vehicle or other vehicle consisting of or comprising said glazing.

According to the invention, the functional layer according to the invention allows to obtain relatively high values of substrate light transmission after heat treatment, while maintaining a significant thermal insulation effect, despite the very small thickness of the functional layer.

In the present description, the terms "underlayer" and "overlayer" refer to the respective position of the layers with respect to one or more functional layers in a stack of layers supported by a glass substrate as a reference.

In particular, the bottom layer is typically the layer in contact with the glass substrate, while the cover layer is the outermost layer of the stack, facing in the opposite direction to the substrate.

Although the application to which the invention is more particularly directed is glazing for the building industry, it is clear that other applications are envisaged, in particular glazing for vehicles (but other than windshields where very high light transmittance is required), such as side glass, sunroofs, and backlights.

The invention and its advantages are described in more detail by the following non-limiting examples according to the invention and by comparison. In all examples and in the description, the thicknesses given are physical thicknesses.

All substrates were made of Planilux type clear Glass of 6 mm thickness sold by Saint-Gobain Glass France.

All layers are deposited in a known manner by magnetic field enhanced cathode sputtering, commonly referred to as magnetron sputtering.

It is known that different successive layers are deposited in successive compartments of a cathode sputtering apparatus, each compartment being equipped with a specific metal target made of Si or Cr, under conditions chosen for depositing a specific layer of the stack.

For example, a silicon nitride layer is formed in a reactive atmosphere containing nitrogen (40% Ar and 60% N)₂) Wherein a silicon metal (doped with 8wt% aluminum) target is deposited in the first compartment of the apparatus. Silicon nitride layer, denoted as Si₃N₄And therefore contains a small amount of aluminum. These layers are then based on the conventional general formula Si₃N₄Meaning that even if the deposited layer does not necessarily correspond to this assumed stoichiometry.

The metallic chromium layer is deposited by sputtering of a Cr metallic target in an inert atmosphere (i.e. by a plasma obtained from gaseous argon only) or in a plasma generated from gaseous argon.

Examples 1 to 5:

in all the subsequent examples 1 to 5, the glass substrate was thus continuously covered with a layer stack comprising a chromium functional layer, which was covered by the first Si₃N₄Layer (underlayer) and second Si₃N₄The layer (cover layer) surrounds. Thus, in these embodiments, the stack consists of a chromium layer encapsulated by two silicon nitride layers in the following order:

glass/Si₃N₄(first layer)/Cr/Si₃N₄(second layer)

Different stacks are combined to tailor the solar factor and light transmission to the various possible configurations required in the construction field.

Thus, in example 1, the thicknesses of the different layers are configured to obtain a glazing with a low solar factor, while corresponding to example 5, it is instead sought to maximise the light transmission through the glazing.

The glass article thus synthesized according to the conventional technique is then heated and quenched (heated at 620 ℃ for 10 minutes and then quenched) according to the conventional technique in the art.

Table 1 below summarizes information on the composition of the sunscreen stacks according to examples 1 to 5 of the present invention:

[ Table 1]

The light transmission T is measured in the range 380nm to 780nm according to the method described in the standard NF EN 410(2011)_LAnd external light reflection R_extAnd internal light reflection R_intValue of (A)_。The solar factor g is also measured according to this standard in the range 300nm to 2500 nm.

The results obtained are summarized in table 2 below:

[ Table 2]

	T_L	R_Lext	R_Lint	∆R_L	g
						Example 1:	22	47	11	36	32
example 2:	28	42	8	34	38
						example 3:	32	30	11	19	42
example 4:	40	34	7	27	48
						example 5:	46	30	10	20	52

it can be seen that the glass articles according to examples 1 to 5 satisfy the above conditions to obtain privacy solar protection glazing, T_LAnd the value of g can be adjusted according to the thickness of the chromium layer.

Also observe that_L(R_Lext-R_Lint) In all cases close to 20, even significantly greater than 20, which allows such guarantees to be obtained within the meaning previously describedThe "privacy" nature of the glazing.

The colorimetric values in transmission, internal reflection and external reflection according to the criteria L, a, b are reported in table 3 below:

[ Table 3]

	a*_TL	b*_TL	a*_RLext	b*_RLext	a*_RLint	b*_RLint
							Example 1:	0.6	-2.3	-1.4	5.3	4.4	-0.5
example 2:	0.6	-2.7	-1.5	4.8	5.8	2.7
							example 3:	1.5	-1.8	-1.4	1.1	-1.8	5.8
example 4:	0.6	-1.3	-1.1	-2.2	3.7	4.3
							example 5:	0.4	-3.5	-1.3	3	1.7	7.4

it can be seen that the values of the coefficients a and b are relatively low and in all cases less than or equal to 8, which represents a relative neutrality of the perceived color in reflection and transmission.

Comparative example:

the properties of the stack of application WO01/21540 cited above can be compared with the properties of the stack according to the invention and described above.

Example 4 of application WO01/21540 describes a stack comprising the following layer sequence:

glass/Si₃N₄(10nm)/Nb(12nm)/Si₃N₄(17nm)。

In the table on page 18 of this publication, the light transmittance is indicated to be 32%. The solar factor g can be calculated to be about 36%. R reported in this publication_LextAnd R_LintEqual to 14% and 25%, respectively.

Although T according to this embodiment of the prior art_LAnd g is comparable to example 2 or 3 reported in Table 2 above, but it can be seen that, within the meaning mentioned above, the values of the external and internal reflections do not allow to obtain the privacy glass, Δ R_LEven negative in this configuration.

Similarly, example 6 of application WO01/21540 describes the sequence of layers in a stack:

glass/Si₃N₄(10nm)/NbN(10nm)/Si₃N₄(15nm)。

In the table on page 18 of this publication, the light transmittance is indicated to be 31%. The solar factor g can be calculated to be about 48%. R reported in this publication_LextAnd R_LintEqual to 18% and 28%, respectively.

Although T according to this embodiment of the prior art_LAnd the value of g is comparable to example 4 reported in Table 2 above, but it can be seen that, within the meaning mentioned above, the values of the external and internal reflections do not allow to obtain the privacy glass, Δ R_LEven negative in this configuration.

Example 6:

in this example, a stack comprising two layers of chromium and corresponding to the following sequence of layers was deposited:

glass/Si₃N₄/Cr/Si₃N₄/Cr/Si₃N₄

The exact composition of the stack is given in table 4, starting from the glass surface:

[ Table 4]

The optical and energy characteristics of the glass substrate are given in table 5 below:

[ Table 5]

	T_L	R_Lext	R_Lint	∆R_L	g
						Example 6:	28	31	8	23	39

the color characteristics of the glass substrate are given in table 6 below:

[ Table 6]

	a*_TL	b*_TL	a*_RLext	b*_RLext	a*_RLint	b*_RLint
							Example 6:	2.3	-1	-0.2	2.8	3.6	1.1

the data reported in the aforementioned tables 4 to 6 show that the stack according to the invention comprising two chromium-based layers also has a very good chromatic neutrality.

Claims

1. A transparent glass article comprising at least one glass substrate provided on at least one of its faces with a coating consisting of a stack of thin layers, at least one functional layer of which provides said article with solar control properties, said coating comprising, with reference to the surface of said substrate, the sequence of:

-a first layer comprising silicon nitride,

-a functional layer based on metallic chromium having a physical thickness greater than or equal to 1nm and less than or equal to 9nm,

-a second layer comprising silicon nitride,

2. The article according to claim 1, wherein the first layer comprising silicon nitride has a thickness of 1-100nm, preferably 10-80 nm.

3. The article according to any one of the preceding claims, wherein the second layer comprising silicon nitride has a thickness of 1-100nm, preferably 1-50nm, more preferably 2-25 nm.

4. The article of any one of the preceding claims, wherein the first layer comprising silicon nitride is thicker than the second layer comprising silicon nitride.

5. The article according to any one of the preceding claims, wherein the stack does not comprise layers based on Ag, Au, Pt, Cu, Ni or stainless steel.

6. The article according to any one of the preceding claims, comprising a single metallic chromium-based functional layer.

7. The article according to the preceding claim, wherein the stack consists of a sequence of the following layers:

SiN_x/Cr/SiN_x

8. The article according to any one of claims 1 to 5, characterized in that said stack comprises two chromium-based functional layers, a third layer comprising silicon nitride being interposed in the stack between said two chromium-based functional layers.

9. The article according to the preceding claim, wherein the third chromium layer is in direct contact with the chromium-based layer according to the following sequence of layers:

SiN_x/Cr/SiN_x/Cr/SiN_x

10. The article of any one of the preceding claims, wherein the one or more chromium-based functional layers comprise more than 70 atomic percent chromium.

11. Article according to any one of the preceding claims, wherein the functional layer or layers, apart from unavoidable impurities, consist essentially of chromium, preferably of chromium.

12. The article of any one of the preceding claims, wherein the first layer comprising silicon nitride is deposited directly on and in contact with the glass substrate.

13. The article according to any one of claims 1 to 11, wherein between the surface of the glass substrate and the first layer comprising silicon nitride there is at least one layer comprising a metal oxide, preferably selected from the oxides of an element selected from silicon, titanium, tin, zinc, aluminium, zirconium, or a mixture of at least two of these elements, in particular silicon oxide, titanium oxide or zinc tin oxide.

14. The article as claimed in any of the preceding claims, wherein at least one layer comprising a metal oxide, preferably selected from the oxides of an element selected from silicon, titanium, tin, zinc, aluminum, or mixtures of at least two of these elements, in particular silicon oxide, titanium oxide, zirconium oxide or mixtures of these oxides, is present above the layer sequence.

15. The article of any one of the preceding claims, which is heat quenched and/or bent.

16. A window bottom wall type exterior wall cladding panel comprising at least one article according to any one of the preceding claims.