US 3865558 A
A glass window has formed along the edge of one or both faces thereof, or along both such edges and over the thickness of the glass, an ornamental strip simulating a frame, the strip including a first layer of silver powder and glass frit baked onto the glass, and bright layers of copper, nickel and chromium successively electroplated onto that first layer and each other.
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Description (OCR text may contain errors)
Unlted States Patent [1 1 [111 3,865,558
Roth et al. Feb. 11, 1975  WINDOW 3,661,538 5/l972 Brown et al. 29/195 lnventorsi Mari" Roih, Aacheniaurensberg; 3,703,445 11i1972 T223381 :1.
Hans Peter Siemonsen, Aachen; 3,716,462 2/1973 Jensen 204/38 13 Siegfried Kuiif, Merkstein; Heinz Moebs, Herzogenrath, all of Germany Saint-Cobain Industries, Neuilly-sur-Seine, France Filed: May 29, 1973 Appl. No.: 364,311
Foreign Application Priority Data June 1. I972 France 72.19666 Lytle 29/195 x Primary ExaminerDewayne Rutledge Assistant Examiner-E. L. Weise Attorney, Agent, or Firm-Pennie & Edmonds  ABSTRACT A glass window has formed along the edge of one or both faces thereof, or along both such edges and over the thickness of the glass, an ornamental strip simulating a frame, the strip including a first layer of silver powder and glass frit baked onto the glass, and bright layers of copper, nickel and chromium successively electroplated onto that first layer and each other.
9 Claims, 4 Drawing Figures WINDOW The present invention pertains to a glass window usable particularly, although not exclusively, in automotive vehicles and having along its edges ornamental strips formed of a metallic coating which give the appearance of a metallic frame around the edge of the window.
The German Offenlegungsschrift No. 1,948,315 describes a window of this character. In the window of that publication the strip or band giving to the window the appearance of a metallic frame is constituted by a thin metallic deposit. Such metallic deposits do not in general possess sufficient resistance to deterioration when they are exposed directly to the atmosphere. They consequently require the protection of a varnish. When such a varnish is applied however, if the metallic coating is to be seen from the exterior of the vehicle (otherwise than through the varnish), it can only be seen by transparency through the glass. Hence the metallic coating must be applied to the face of the glass toward the inside of the vehicle. With such an arrangement an observer from outside the vehicle does not obtain the impression ofa metallic frame or channel binding or enclosing the edge of the glass.
Another shortcoming of the deposits of silver or other metal on glass of the above-identified publication is that their adhesion to the glass is often insufficient. When substantial mechanical stress is applied thereto, as sometimes occurs with automobile windows, this poor adhesion results in peeling and separation of the coating from the glass. It is an object of the present invention to provide an ornamental strip whose composition and mode of application are such that the strip adheres strongly to the glass, possesses great resistance to mechanical stress such as friction or abrasion, and also high resistance to chemical attack. The strip of the invention can thus be applied to the outer face of the window, i.e. to the surface of the glass outside the vehicle, and hence gives the impression from the exterior of the vehicle of a heavy metallic frame.
This strip or band is produced, according to the invention, starting from an enamel. The enamel is made up of a ceramic paste of silver powder dispersed in a glass frit and is laid down on the glass by a silk screen technique, where it is then baked at high temperature. Such an enamel will hereinafter sometimes be referred to as a silver enamel. A layer of bright copper is then electrolytically deposited on this silver enamel. The coating is completed with a layer of bright nickel and finally with a layer of bright chromium.
These bright copper, nickel and chromium layers may advantageously be laid down by electrolytic plating, control of the nature of the plating baths making it possible to give to the strip any final finish from a perfect brightness to a satin or semi-bright finish.
It is known, in the manufacture of heated windows, for example for use in automobiles, to deposit on glass surfaces strips or bands of electrically conductive material. This known process comprises applying to the glass and baking thereon a layer of conductive enamel made from a ceramic paste including silver. This layer is then reinforced by electrolytic plating, preferably first with a layer of copper and then with a layer of nickel which is provided for protection against corrosion. It often appears, however, that even the addition of a further layer of chromium is not sufficient to provide a bright coating having both the desired ornamental appearance and sufficient strength and permanence.
The invention departs from the prior art process above described in that, while it uses a baked silver powder-ceramic layer as a foundation, there are laid down thereon successively three bright layers of copper, nickel and chromium respectively. The superposition of the two bright underplatings suffices to produce a smooth surface from the relatively rough surface of the glass, and makes it possible to use a very thin final layer of chromium. The resulting strip has the appearance of a massive metallic frame, highly polished.
To achieve this result, in accordance with the invention, it is sufficient to lay down the successive layers with the help of bright plating baths in which suitable additives are provided to achieve a smooth surface for the plated coating. Such bright plating baths for copper, nickel and chromium are known in the art of electroplating.
Applicants have found that particularly strong, durable and well-adhering layers are obtained on the glass by making the bright copper, bright nickel and bright chromium layers of the following thicknesses:
Copper layer: Average thickness between 3 and 15 microns and preferably between 5 and 8 microns.
Nickel layer: Average thickness between 3 and and 15 microns and preferably between 7 and 10 microns.
Chromium layer: Thickness below 1 micron and preferably below 0.5 micron.
A preliminary smoothing of the underlying enamel layer may be effected either mechanically or chemically, which then makes it possible to reduce somewhat the thickness of the copper layer. For laying down the nickel and chromium layers it is possible, in accordance with the invention, to use one or another of the known chemical processes although the relative slowness of such operations constitutes a disadvantage by comparison with electrolytic plating methods.
Windows provided with ornamental strips, in accordance with the invention, have the same mechanical and chemical durability as windows supported in massive chromium plated metal frames, and they have in addition the advantage that the ornamental strips are inseparably attached to the glass.
BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be further described in terms of a number of presently preferred exemplary embodiments thereof and by reference to the accompanying drawings wherein:
FIG. 1 is a section through a window including an ornamental strip having on one face of the glass, when seen in plan, the shape of a frame;
FIG. 2 is a section through a window having ornamental strips on its two faces;
FIG. 3 is a section showing another embodiment wherein the edge of the window is bound in a stripshaped coating in accordance with the invention; and
FIG. 4 is a perspective view of one preferred form of window according to the invention.
DESCRIPTION OF PREFERRED EMBODIMENTS The window of the invention may have any shape or outline. It may be used as a side window, as a windshield, or as a rear window in automobiles. It may also find use in building construction for windows, mirrors,
doors or the like, and also in furniture, or in refrigerators and ovens, to name a few examples only.
In the examples illustrated, the window comprises a single sheet of glass (which may be glass made for example by the float process) and the ornamental strip or strips affixed thereto. These are identified at A, B, C and D in FIGS. 1 to 4 respectively. The strip may extend all the way around the periphery of the sheet of glass in the fashion of a frame. Obviously however it need not have such a closed shape. It is often sufficient for the strip to extend only part way around the periphery of the glass.
This is notably the case for the adjustable side glass of automobiles which may include the ornamental strip only at the upper edge thereof. It may in other instances be sufficient to provide the ornamental strip around three sides of the window, for example when the fourth side is held in a frame. It may be sufficient in certain cases to provide the ornamental strip only along short sections or parts of the periphery of a window.
As may be seen in each of the figures, the ornamental strips are all made in the same way. The foundation layer 2 is made up of a commercially available metallic paste baked onto the surface of the glass and comprising, by weight, about 90 percent of finely divided metallic silver and 10 percent of a glass frit having a low melting point. This metallic paste, dispersed in an or ganic solvent, is applied by the silk screen technique to the surface ofa glass sheet. In the case of float glass, i.e. glass made by the well-known float process in which the glass is floated on a bath of molten metal, the paste is preferably applied to the surface of the glass which was uppermost in manufacture, i.e. not in contact with the metallic float bath. It is then baked at a temperature of at least 500C. After baking the thickness of the silver layer 2 is of the order of 3 to 6 microns.
In the embodiment of FIG. 1, the layer 2 on the glass 1 is then coated electrolytically, i.e. by electrolytic deposition, with a layer of bright copper 3 from 3 to 7 microns thick. An electrolyte providing a bright plating is used to obtain a sufficiently smooth surface. The layer 3 should have a thickness of at least 3 microns.
On the layer 3 there is next laid down electrolytically a bright nickel plating 4 having a thickness of about 10 microns, and on this there is laid down electrolytically a bright chromium plating having a thickness between 0.1 and 0.5 micron. The result is of impeccable appearance and possesses good mechanical and corrosion resistance properties.
In the embodiment of the invention illustrated in FIG. 2, the two ornamental strips B have the same width and are disposed along the edges of the glass on its two faces.
FIG. 3 illustrates an embodiment in which the ornamental strip C straddles the edge of the glass 20, i.e. the face of the glass parallel to the thickness dimension of the glass.
The figures do not attempt to show the relative thickness of the layers 2 to 5, either by reference to each other or by reference to the thickness of the glass.
The width of the ornamental strips may be of the order of I to 3 centimeters.
In the embodiment illustrated in FIG. 1 the layer of silver paste baked onto the surface of the glass 1 and indicated by reference character 2 may be seen by transparency through the glass. As a general rule this layer when so observed will show a brown color due to silver ions which have diffused into the surface layers of the glass. In applications where such a color is undesirable, it is possible to avoid the effect thereof by laying down on the opposite face of the glass, i.e. on the lower face of the glass as seen in FIG. 1, and opposite the strip A, a colored strip 7 made up for example of an enamel or of a lacquer. In the case of an automobile window the chromium layer 5 should be on the exterior side of the vehicle, so that the lacquer strip 7 would be on the inside. In FIG. I the upper face 8 of the glass sheet 1 is the one intended to be the outside" face of the window in use, i.e. the one presented to the weather. In automobile use it will often be convex in shape, whereas the opposite face 9 to which the colored lacquer strip 7 is applied will be concave.
Whereas in the embodiment illustrated the metallic strips or coatings are disposed along the edge of the glass, of course they need not be located there.
FIG. 4 illustrates an embodiment of the invention of particularly advantageous nature. In FIG. 4 the first layer 2 of the strip, i.e. the silver powder-glass frit layer, extends out beyond the other layers 3 to 5 of the strip as a shelf or shoulder E onto the side or thickness face 31 of the glass 30. The electrode for plating purposes can be connected to the shoulder or contact tab E thus formed. This arrangement has the advantage that the visible face of the glass in the finished window will not show any traces of the electrode, whose location usually results in a dark area on the glass. It is possible to choose the position for the contact tab E in such a way that it will be hidden by the window mounting. When the ornamental strip extends only over three sides of the periphery of the window as in the embodiment of FIG. 4, it is advantageous to locate the tab E in the middle of the length of the strip. When the strip has a great length, as in the case of large windows, it is advantageous to provide several contact tabs for the connection of plating electrodes, since the drop in voltage along the strip will result in a variation, along the length of the strip, in the thickness of the plating laid down. Satisfactory results are obtained by providing contact tabs at intervals of about 1 meter. These tabs may be formed by means of a paint brush, used to draw out the silver powder-glass frit paste from a strip-shaped deposit so as to form a tab before the paste is baked onto the glass.
The following is an example of the process by which the windows of the invention may be made:
1. A commercially available metallic paste is laid down by the silk screen process on the glass at room temperature in the shape of the desired strip or strips. The glass with the paste thereon is then baked at a temperature of about 600C. The layer of silver thus obtained, having a thickness of the order of 3 to 6 microns, is smoothed by mechanical polishing with a rotating brush and an aqueous suspension of silica and alumina powder. The electrodes are then placed in position for the plating operations.
2. A bright copper plating is laid down on the silver with a plating bath at a temperature of from 20 to 25C., employing a current density of 5 amperes per per square centimeters and continued for 5 minutes.
3. The assembly, i.e. the glass with the silver paste strip or strips thereon, now plated with copper, is washed with water.
4. The assembly, and more particularly the copper plating thereon, is pickled in a solution of sulphuric acid.
5. A bright nickel plating is laid down on the copper with a plating bath at a temperature of 60C., employing a current density of 2.5 amperes per 100 square centimeters and continued for minutes.
6. The assembly is washed in water.
7. The assembly is soaked in a preparatory solution at a temperature of C.
8. A bright chromium plating is laid down on the nickel with a plating bath at a temperature of 30C., employing a current density of 5 amperes per 100 square centimeters and continued for 1 minute.
9. The assembly is washed in water.
While the invention has been described hereinabove in terms of a number of presently preferred embodiments, the invention is not limited thereto, but rather comprehends all modifications of and departures from those embodiments properly falling within the scope of the appended claims.
1. A window comprising a sheet of glass, a layer of silver enamel of generally strip shape baked onto a part of the surface of the sheet, a bright copper layer overlying the enamel layer, a bright nickel layer overlying the copper layer, and a bright chromium layer overlying the nickel layer.
2. A window according to claim 1 wherein the copper and nickel layers have each a thickness between 3 and 15 microns and wherein the chromium layer has a thickness of less than 1 micron.
3. A window according to claim 1 wherein the enamel layer is adjacent an edge of one face of the glass.
4. A window according to claim 1 wherein the sheet is of float glass and wherein the layer of enamel is applied to the face of the sheet which was uppermost during the float.
5. A window according to claim 1 including a strip of enamel or lacquer opposite said first-named layer of enamel but on the face of the glass opposite that to which said first-named layer of enamel is baked.
6. A window according to claim 1 wherein the window is shaped to define outside and inside surfaces therefor and in which the enamel layer is applied to the outside surface thereof.
7. A window according to claim 6 including a strip of enamel or lacquer opposite said first-named layer of enamel but on the face of the glass opposite that to which said first-named layer of enamel is baked.
8. A window according to claim 1 wherein said layer of enamel includes at least one portion extending onto the face of the glass parallel to its thickness dimension.
9. A window according to claim 1 wherein said layer of enamel extends to both side faces and to one thickness face of the glass.