FR2857958A1 - Substrate protected against irisation by coating a layer with a base derived from silicon oxides, for a wide range of glazing applications that may be subjected to hot, humid and confined atmospheres - Google Patents

Abstract

A substrate sensitive to attack by hydrolysis with element elimination is directly covered with a layer with a base derived at least partially from silicon oxides with a thickness sufficient to suppress all irisation during transport and then storage of the substrate in a humid, hot and confined atmosphere. Independent claims are also included for: (a) a pile of glass sheets including at least one such substrate; (b) the formation of the silicon oxide derived coating on a glass substrate; (c) a monolithic, laminated, simple or multiple glazing including at least one such substrate.

Description

SUBSTRATE TREATED AGAINST IRISIS

  The present invention relates to the problem of the iridescence of certain substrates likely to appear especially in humid, hot and confined atmosphere.

  Under such conditions, certain substrates undergo a hydrolytic attack creating surface irregularities visible in reflection in the form of lines in the colors of the rainbow, a phenomenon called iridescence. This phenomenon is found in a manner known to those skilled in the art after transport and storage.

  The hydrolytic attack relates particularly to materials containing alkalis capable of migrating to the surface; this is the case for example of the atmosphere face of the float glass silicosodocalcique, unlike the tin side (in contact with the bath of tin) which is protected. In addition, the iridescence is particularly troublesome in the case of such a transparent substrate and / or for which optical properties and / or perfect flatness are required.

  The invention therefore aims to significantly reduce or even eliminate the iridescence. In the production of flat glass, the aim is the possibility of transporting and storing for long periods of stacks of glass sheets including hot, humid and confined atmosphere as encountered in South East Asia for example. One of the advantages secondarily obtained is the possibility of increasing the volumes and reducing the frequencies of special productions as to the composition of the glass, the thickness of the sheet or on any other plane.

  This object is achieved by the invention which relates to a substrate sensitive to hydrolytic attack by element outlet, characterized in that it is directly covered with a layer based on at least partially oxidized derivative of the selected silicon. from silicon dioxide or sub-stoichiometric oxides of silicon oxygen, in a sufficient thickness to suppress any noticeable iridescence during transport, and then storage of the substrate in humid, hot and confined atmosphere. The term storage refers to a usual duration for the products concerned, in particular glazing, that is to say generally from a few weeks to a few months, rarely exceeding a period of two years, and never five years. .

  For the purposes of the invention, a substrate is susceptible to hydrolytic etching by element outlet when it undergoes corrosion in a humid medium due to the surface migration of one or more of its constitutive elements.

  The silicon derivative may comprise only the elements Si, O in the case of SiO 2, the elements Si, O, N in the case of an oxynitride and Si, O, C in the case of an oxycarbide. But the silicon derivative according to the invention also comprises materials which also contain, in a minority manner with respect to silicon, at least one metal such as aluminum, zinc or zirconium. The addition of a metal can have the following advantages: by reactive cathodic sputtering, this amounts to spiking the Si target to make it more conductive, which accelerates / facilitates the deposition. In addition, whatever the mode of deposition (by pyrolysis for example), the addition of an aluminum type metal can increase the durability of the material, especially in the case where it is low carbonélazoté.

  For the purposes of the invention, the silicon derivative also includes sub-stoichiometric silicon oxides of formula SiOx, with x less than 2.

  The invention is therefore particularly applicable to a glass substrate, a glass-ceramic or similar. Although essentially planar products, for which optical quality is required, are particularly targeted, the substrate of the invention may also be in other forms, including bottles, flasks, jars, fibers, tubes (in lighting applications for example) as far as these forms may be concerned with the problem of iridescence.

  On the other hand, in this case of a glass substrate, a glass-ceramic or the like, alkali-containing compositions are particularly targeted, whether it be silicosodium-calcium glass, borosilicate glass or glass-ceramic. This is because the migration of alkalis on the surface is known, and the resulting reduction in the resistance of the material containing them to hydrolytic attack.

  In the case of float glass, in particular of the silicosodium-calcium type, it is preferably the atmosphere face, ie that which is not in contact with the molten tin bath, which is directly coated with the at least partially oxidized derivative-based layer of silicon. It turned out that the other side, called the tin face, was already protected from iridescence due to the hydrolytic attack.

  According to a characteristic of the substrate of the invention, the thickness of the layer based on at least partially oxidized silicon derivative is at least 1 nm, preferably at least 5 nm, an anti-irisation effect being already demonstrated for a value as low as the first cited, the second being likely to ensure increased durability of the layer and its function. Larger thicknesses, especially at least 30 nm, while achieving the object of the invention, reduce the light transmission and are, of course, a more expensive embodiment.

  Other objects of the invention are: a stack of glass sheets, at least one of which consists of a substrate according to the invention; a method of storing such a stack of glass sheets, especially in a humid and hot atmosphere.

  Indeed, the glass sheets are usually transported under variable conditions and stored in dimensions of 6 m × 3 m for example, stacked in vertical position at slightly inclined, and separated from each other by means of interleaves by blades confined air several millimeters thick. In addition, as explained above, the invention provides the solution to a problem that has arisen particularly in humid and hot atmosphere, in this case the climate of Southeast Asia.

  When the substrate is of flat glass, two types of formation of said layer based on at least partially oxidized silicon derivative are possible, which constitutes a further advantage of the invention: either the formation is integrated in the float line. ; - Or carried out off-line float, and in this case on sheets of PLF dimensions (full width float) mentioned above, or on sheets cut to the dimensions of the final product, and optionally heat treated (hardened, tempered), curved, laminated ... if however the chosen training technique of the layer -see below in detail- allows it.

  Consequently, these two variants of the method of forming the layer constitute other objects of the invention.

  Preferably, this process consists of a process under vacuum or at reduced pressure - preferably carried out off-line float - such as cathodic sputtering, in particular assisted by magnetic field, or plasma CVD, or in a process at atmospheric pressure - put into operation. work on or off float - such as sol-gel or pyrolysis, especially in the vapor phase (thermal CVD).

  On the other hand, the subject of the invention is: monolithic, laminated, single or multiple glazing comprising at least one substrate as described above; and - the application of such glazing to the building, to a transport vehicle, in particular to a windshield, a rear window, a side window or an automobile roof, to any other land, air or water vehicle, street furniture such as abribus, traffic sign or advertising sign, landing-line reflector, exterior or similar lamp window, aquarium, showcase, greenhouse, interior furnishing, mirror , a display system of the computer type, television, telephone, an electrically controllable glazing such as electrochromic glazing, liquid crystal, electroluminescent or photovoltaic glazing.

  The invention is illustrated by the following example.

EXAMPLE

  A layer of silicon oxycarbide 7.4 nm thick by CVD according to patent EP 518 755 from SiH 4, ethylene and aluminum is deposited on a clear glass silicolodalcium of the Planilux type sold by Saint-Gobain Glass France. 'oxygen.

  Resistance to hydrolytic attack is evaluated both on this substrate and on a Planilux glass without the protective layer. Accelerated hydrolytic etching is carried out by a test consisting of interposing between two 12 cm x 12 cm plates of Planilux naked on the one hand, of Planilux coated with silicon oxycarbide (coated faces) on the other hand, with demineralized water in contact with the surface of the plates, sealed from a water bath at 96 ° C. in which the assembly is immersed by a silicone gasket 3 mm in diameter, two electrodes being immersed in water Demineralized and connected to a bridge for measuring electrical conductance.

  The appearance of iridescence corresponds to a sudden growth characteristic of electrical conductance. For bare glass, this growth appears about 200 minutes, and for SiOC-coated glass, beyond 1500 min. The substrate of the invention has a total absence of iridescence under the actual storage conditions in countries such as India.

  The layer based on at least partially oxidized silicon derivative has excellent adhesion and mechanical properties (abrasion resistance, friction resistance). It is compatible with various transformations: 5 enamelling, heat treatment (hardening, tempering), bending, cutting (conventional, water), screen printing, edge forming, laminating, without the optical properties (light transmission, veil) in are significantly affected, and without difficulty in adapting the conditions of implementation of these transformations. It is thus possible, in order to benefit from the anti-iridescence functionality provided by the invention, to store SiOC-coated bare glass even under rigorous climatic conditions and for long periods of time, and then to functionalize it either on PLF sheets or on cut sheets. , including deposition of additional functional layers or stacks.

  Finally, although coating, according to the invention, bare glass in particular the silicosodocalcique by the protective layer, gives excellent results, all layers, all usual functional stacks (thermal control function - antisolar, low-emissive -, optical function such qu'antireflet, filtrationcoloration, electroconductive, semiconductor, antistatic ... for example) are likely to be interposed between the glass and said protective layer without departing from the scope of the invention, so far that all they form with the glass is sensitive to hydrolytic attack by element output.

Claims (10)

  1. Substrate sensitive to hydrolytic attack by element outlet, characterized in that it is directly coated with a layer based on at least partially oxidized derivative of silicon selected from silicon dioxide or sub-oxides. stoichiometric oxygen silicon, oxycarbide or silicon oxynitride, in a sufficient thickness to remove any iridescence perceptible during transport, and then storage of the substrate in humid, hot and confined atmosphere.   2. Substrate according to claim 1, characterized in that it consists of a glass substrate, a glass-ceramic or similar.   3. Substrate according to claim 2, characterized in that is directly covered with said layer the atmosphere of float glass, in particular of the silicosodocalcique type.   4. Substrate according to one of the preceding claims, characterized in that the thickness of the layer is at least 1 nm, in particular at least 5 nm, and preferably at most 30 nm.   5. Stack of glass sheets, at least one of which consists of a substrate according to   one of the preceding claims.   6. A method of forming, on a flat glass substrate according to one of claims 1 to 4, said layer based on at least partially oxidized derivative of silicon, characterized in that it is implemented on a float line.   7. A method of forming, on a flat glass substrate according to one of claims 1 to 4, said layer based on at least partially oxidized derivative of silicon, characterized in that it is implemented offline float .   8. Process according to claim 6 or 7, consisting of a vacuum or reduced pressure process such as cathodic sputtering, in particular magnetic field assisted, or plasma CVD, or in an atmospheric pressure process such as by sol-gel method. or by pyrolysis, especially in the vapor phase (thermal CVD).   9. Monolithic, laminated, single or multiple glazing comprising at least   a substrate according to one of claims 1 to 4.   10. Application of a glazing according to claim 9 to the building, to a transport vehicle such as windshield, rear window, side window or car roof, to any other land vehicle, air or water, street furniture such as abribus, traffic sign or advertising sign, landing-line reflector, outdoor lamp window or the like, aquarium, showcase, greenhouse, interior furnishing, mirror, screen computer-based display system, television, telephone, electrically controllable glazing such as electrochromic, liquid crystal, electroluminescent glazing or photovoltaic glazing.