IES83455Y1 - A method for applying a pattern to a glass panel - Google Patents

Abstract

ABSTRACT A method for applying a pattern (10) to a glass panel for simulating a Georgian style lattice window comprises applying a surface coating composition to form bands (14,15) of the pattern (10) by airless spraying through a nozzle (20). The surface coating composition comprises a mineral based ink of the type suitable for ceramics applications which is provided in powder form of particle sizes in the range of (1) micron to (7.6) microns. The mineral based ink is mixed with a liquid solvent for agglomerating the particles, and colour pigment is added as appropriate. The surface coating composition is applied to an inner surface (11) of the glass panel (3) to a depth of approximately (200) microns to form the bands (14,15). The surface coating composition of the bands (l4,l5) is then dried, and the panel (3) is then toughened at a toughening temperature of the order of (700°)C for a time period of approximately one and a half minutes, which also causes the surface coating composition forming the pattern (10) to fuse to the glass.

Description

"A method for applying a pattern to a glass panel" The present invention relates to a method for applying a pattern to a glass panel, and the invention also relates to a glass panel having a pattern applied thereto by the method.

There are many instances in which it is desirable to apply a pattern to a glass panel, and in particular, there are many instances where it is desirable to apply the pattern to the glass panel so that the pattern is clearly defined by well defined edges, rather than by feathered edges. For example, in the provision of Georgian and Tudor style lattice type windows, it is desirable that the criss-cross bars of the pattern simulating the lattice appear to be genuine criss-cross bars. In the manufacture of double glazed windows where the window pane is formed by two panes of glass, namely, an inner and an outer pane which are spaced apart one from the other, it is known to locate spacer bars which are arranged in a criss-cross manner between the inner and outer glass panes for simulating a Georgian or Tudor style lattice. Typically, such spacer bars are of metal, for example, hollow box section aluminium, and are of thickness corresponding to the spacing between the inner and outer glass panes, which typically, is 12mm. The width of the bars depends on the desired width of the criss-cross members being simulated, and can range from 6mm, in the case of a Tudor style window, to up to 28mm in the case of a Georgian style window.

However, the problem with simulating Georgian and Tudor style lattice windows with such spacer bars is that the spacer bars act as a cold bridge for conducting heat between the inner and outer glass panes of the double glazed window, thus significantly increasing heat loss through the double glazed window pane.

An alternative to the use of spacer bars in the simulation of Georgian and Tudor style lattice windows is to stick lead strips to the glass pane to simulate the Georgian or Tudor style lattice. The use of stick-on lead strips is suitable for both single and double glazed windows However, the use of such lead strips is environmentally unfriendly, and for this reason their use is undesireable.

It is also known to simulate Georgian and Tudor style lattice windows by painting the criss-cross members onto the glass pane. However, in general, the simulation of such Georgian and Tudor style lattice windows, whether single or doubled glazed, with painted criss-cross members tend not to look authentic. This is commonly due to the fact that the edges defined by the simulated criss-cross members are feathered as a result of over-spray, and secondly, in general, the simulated criss- cross members tend to be translucent, and thereby lack authenticity.

There is therefore a need for a method for providing simulated Georgian and Tudor style lattice windows, both double and single glazed, and there is also a need for such a simulated Georgian or Tudor style lattice window. Further, there is a need for a method for applying a pattern to a glass panel which overcomes the problems of known methods, in particular, though not limited to the problems associated with feathered edges, and translucence of the pattern.

The present invention is directed towards providing such a method and a window pane, and the invention is also directed towards providing a glass panel having a pattern applied thereto.

According to the invention there is provided a method for applying a pattern to a glass panel, the method comprising the steps of applying a mineral based ceramic ink to the glass panel to form the pattern, wherein the mineral based ink is applied by airless spraying, and the mineral based ink comprises an agglomerating agent for agglomerating the molecules of the mineral based ink together.

Preferably, the mineral based ink is in powder form prior to mixing with the agglomerating agent.

In one embodiment of the invention the agglomerating agent is a solvent. in another embodiment of the invention the solvent is diethylene glycol monobutyl ether. Alternatively, the solvent is propylene glycol methyl ether, or alternatively, the solvent may be methoxy-1, 2-propanol. The solvent may also be propylene g|ycol—1— methyl ether, or methoxy-1, 2-hydroxpropane, or methyl propylene glycol, or any similar type dilutents.

In another embodiment of the invention the mineral based ink is in powder form, and preferably, is of relatively small particle size, and advantageously, of particle size in the range of 1 micron to 10 microns, and ideally of particle size in the range of 1 micron to 7.6 microns. in another embodiment of the invention the mineral based ink comprises 2(C- butoxye thoxy) ethanol, lead cadmium.

In another embodiment of the invention the mineral based ink comprises a colour pigment for defining the colour of the pattern.

In a further embodiment of the invention the mineral based ink is applied by the airless spraying through a nozzle having a circular bore, which preferably converges in one plane for defining an elongated nozzle outlet. ideally, the nozzle outlet defines a jet of the mineral based ink of rectangular cross-section, and preferably, the length of the cross-section is considerably greater than the width of the cross- section of the jet of mineral based ink, and ideally, the length is at least five times the width, and preferably, up to ten times the width of the rectangular cross-section of the jet of mineral based ink.

In another embodiment of the invention the bore diverges in a plane at right angles to the plane in which the bore converges, and preferably, the rate of diverging of the bore of the nozzle is such as to provide the jet of mineral based ink to exit in a fan shape, and preferably, a fan having diverging edges which diverge at an angle in the range of 5° to 40°, and preferably, in the range of 10° to 30°, and ideally, the fan edges defined by thejet of mineral based ink diverge at an angle of approximately °.

In another embodiment of the invention the bore of the nozzle is of diameter in the range of seven thousandths of an inch to fifteen thousandths of an inch.

In a further embodiment of the invention the mineral based ink is pressurised to a pressure in the range of 120 bar to 300 bar, and preferably, the pressure of the mineral based ink is selected along with the speed of movement of the nozzle relative to the surface of the glass panel on which the pattern is being formed for depositing the mineral based ink on the surface of the glass panel so that the mineral based ink is deposited on the surface of the glass panel to the desired depth.

In one embodiment of the invention the mineral based ink is deposited to a depth of at least 150 microns, and preferably, to a depth of at least 175 microns, and ideally, to a depth of at least 200 microns. in another embodiment of the invention the mineral based ink is deposited on the surface of the glass panel to a depth in the range of 200 microns to 250 microns.

In a further embodiment of the invention the spacing of the nozzle outlet from the glass panel is selected to minimise feathering of an edge defining the pattern, and additionally, the spacing of the nozzle outlet from the glass panel may be selected for determining the area of the surface of the glass panel on which the paint is being deposited.

In one embodiment of the invention the nozzle outlet is spaced apart from the surface of the glass panel a distance in the range of 10mm to 40mm, and preferably a distance of approximately 20mm.

In one embodiment of the invention the glass panel after the pattern has been applied thereto is subjected to a high temperature treatment for fusing the pattern to the glass. In one embodiment of the invention the glass panel and the pattern are subjected to a fusion temperature in the range of 650°C to 750°C.

In another embodiment of the invention the pattern is fused to the glass panel during heat treatment of the glass panel for toughening thereof.

In another embodiment of the invention the pattern is subjected to a drying temperature for drying the pattern after the pattern has been applied to the glass panel, and prior to the pattern being fused to the glass panel.

In one embodiment of the invention the glass panel with the pattern applied thereto is subjected to a temperature in the range of 90°C to 100°C for drying the pattern, and preferably, the drying of the pattern is carried out by subjecting the pattern to infrared heat.

In another embodiment of the invention the pattern is a criss-cross pattern for simulating a lattice type window, and in one embodiment of the invention the criss- cross pattern simulates a Georgian lattice type window, and in another embodiment of the invention the criss-cross pattern simulates a Tudor style window.

Additionally the invention provides a glass panel having a pattern applied thereto by the method according to the invention. In one embodiment of the invention the glass panel is a window pane, and in another embodiment of the invention the glass panel is a window pane of a double glazed window, and preferably, the pattern is applied to an inner surface of the outer glass pane of the double glazed window.

The invention will be more clearly understood from the following description of an embodiment thereof, which is given by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a front elevational view of a double glazed window unit according to the invention, Fig. 2 is a transverse cross-sectional side elevational view of the double glazed window unit of Fig. 1, Fig. 3 is an enlarged perspective view of a portion of the double glazed window unit of Fig. 1, Fig. 4 is a perspective view of a spray nozzle for use in the method according to the invention, Fig. 5 is a transverse cross-sectional view of the nozzle on the line V-V of Fig. 4, and Fig. 6 is a transverse cross-sectional view of the nozzle on the line VI-Vl of Fig. 4, Fig. 7 is a diagrammatic side elevational view of the spray nozzle of Fig. 4 mounted relative to a glass pane of the double glazed window unit of Fig. 1 during spraying of a pattern onto the window pane, and Fig. 8 is a diagrammatic top plan view of the spray nozzle and window pane of Fig. 7.

Referring to the drawings and initially to Figs. 1 to 3 thereof, there is illustrated a double glazed window unit according to the invention, indicated generally by the reference numeral 1. The double glazed window unit 1 comprises an inner pane 2 of glass, and an outer pane 3 also of glass. The inner and outer panes 2 and 3 are spaced apart and define a cavity 4 therebetween. A spacer member 6 extends around the periphery of the inner and outer panes 2 and 3 between the respective panes 2 and 3 for spacing the panes 2 and 3 apart to form the cavity 4. A sealing band 7 extends around the periphery of the window unit 1, and sealably engages peripheral edges 8 and 9 of the inner and outer panes 2 and 3, respectively, and the spacer member 6 for sealing the inner and outer panes and the spacer member 4 for sealing the cavity 4. The inner pane 2 in this embodiment of the invention is of a heat reflective glass. Such heat reflective glasses will be well known to those skilled in the art.

A pattern 10 which simulates a Georgian style lattice window is applied to an inner surface 11 of the outer pane 3 within the cavity 4 prior to assembling the inner and outer panes 2 and 3 of the double glazed unit 1. The method for applying the pattern 10 to the outer pane 3 comprises applying a mineral based ink to the inner surface 11 of the outer pane 3 by airless spraying as will be described below. The pattern 10 comprises a plurality of horizontal bands 14 and vertical bands 15 which simulate the lattice. In this embodiment of the invention since the lattice pattern is simulating a Georgian style window, the horizontal and vertical bands 14 and 15 are of width w 20mm, and the mineral based ink is deposited to a depth d of approximately 200 microns in order to ensure that the bands are opaque. The method, as will be described below, is such as to ensure that edges 16 of the bands and 15 are sharply defined without feathering.

Turning now to the method according to the invention for forming the pattern 10, the mineral based ink which is applied to the inner surface 11 of the outer pane 3 is provided in two parts, namely, a powder part and a liquid part which are thoroughly mixed together. The mineral based ink is provided as the powder part, and the liquid part is a solvent, which comprises an agglomerating agent. Additionally, in this embodiment of the invention the bands 14 and 15 are white, and thus, the mineral based ink in powder form also includes a suitable white pigment. The mineral based ink in powder form is supplied by Johnson Matthey PLC of Stoke on Trent, England and is supplied under the name of fine white and contains 2(2-butoxye thoxy) ethanol, lead cadmium. The particle size of the mineral based ink is in the range of micron to 7.6 microns.

The solvent which includes the agglomerating agent for agglomerating the ink molecules together for avoiding over-spray and thus defining sharp edges 16 of the bands 14 and 15 in this embodiment of the invention is diethylene glycol monobutyl ether and is manufactured by Fluka Chemie GmbH of Bucks, Switzerland and supplied by Sigma Aldrich Chemie GmbH. The solvent is mixed with the mineral based ink in the proportion four parts by volume mineral based ink powder to approximately one part solvent by volume and the powdered mineral based ink and solvent are thoroughly mixed. The liquid ink is then applied to the outer pane 3 by airless spraying.

Referring now to Figs. 4 to 8 the airless spraying of the liquid ink onto the surface 11 of the outer pane 3 will now be described. The liquid ink is pressurised to a pressure in the range of 120 bar to 300 bar, and typically, 140 bar, and is applied to the outer pane 3 by the airless spraying through a spray nozzle 20. The spray nozzle 20 defines a rectangular shaped nozzle outlet 22 through which the pressurised liquid ink is applied to the pane 3 to form the pattern 10. A circular bore 24 of diameter D of approximately 7 microns extends through the spray nozzle 20 and converges in one plane to define long edges 26 of the nozzle outlet 22, and the bore 24 diverges in a plane at right angles to the converging plane for defining short edges 27 of the nozzle outlet 22, see Figs. 4 to 6. The bore 24 diverges at an appropriate angle for defining a jet 28 of the liquid ink issuing from the nozzle outlet 22 with a fan angle on of approximately 30°, see Fig. 7.

Ajig (not shown) is provided for supporting the pane 3 horizontally with the inner surface 11 to which the pattern 10 is to be applied facing upwardly. The nozzle 20 is carried on a numerically controlled carrier (also not shown), and is directed downwardly for applying the jet 28 of liquid ink to the surface 11 of the pane 3 so that the jet 28 is directed vertically downwardly at the surface 11. The numerically controlled carrier urges the spray nozzle 20 at an appropriate speed relative to the surface 11 of the pane 3, which is set depending on the pressure to which the liquid ink is pressurised, so that the ink is deposited to a depth of 200 microns on the surface 11 for forming the bands 14 and 15. Additionally, the spacing of the nozzle outlet 22 above the surface 11 of the paint 3 is set at a distance 8, see Fig. 7, such that over-spray is minimised and in practice is eliminated for avoiding feathering of the edges 16 of the bands 14 and 15. it has been found that with a jet angle of 30° and the pressure set at approximately 140 bar, the optimum spacing 8 between the nozzle outlet 22 and the surface 11 is approximately 20mm. it has been found that if the spacing D between the nozzle outlet 22 and the surface 11 is too close, the jet 28 on impinging against the surface 11 rises what is effectively a bow wave on its leading edge, which can cause distortion of the bands, particularly when one of the bands, for example, one of the horizontal bands, is crossing over an already applied vertical band. if the spacing S is too great, it has been found that over-spray commences, thus leading to feathering of the edges 16 of the bands 14 and 15.

Referring now to Figs. 7 and 8, the width w of the bands 14 and 15, as well as being determined by the spacing S between the nozzle outlet 22 and the surface 11 is also determined by angling the nozzle outlet 22 relative to a central axis 29 of the bands 14 and 15. The noule outlet 22 defines a longitudinally extending axis 30, and the longitudinal axis 30 is angled relative to the central axis 29 at an angle (p. In this embodiment of the invention since the bands 14 and 15 are to be of width approximately 20mm, the angle (p is approximately 45°. Where it is desired to form a wider band than the bands 14 and 15, the angle (p is appropriately increased. To form a narrower band the angle (p is appropriately decreased. It has been found that in order to form a band of approximately 6mm, which would be a typical width for bands simulating a Tudor style lattice, the angle (p is approximately zero, in other words the two axes 29 and 30 coincide.

The numerically controlled carrier (not shown) urges the spray nozzle 20 over the pane 3 for forming the vertical bands 15 first, and when the vertical bands 15 have been formed, the numerical controlled carrier (not shown) then urges the spray nozzle 20 over the pane 3 for forming the horizontal bands 14.

After the bands have been formed on the pane 3 the ink forming the bands 14 and is dried under infrared radiation. The bands 14 and 15 are raised to a temperature in the range of 90°C to 100°C for a period of approximately ten minutes for drying thereof.

After drying, the pane 3 is then placed in a toughening oven for toughening the pane . The temperature of the pane 3 and the bands 14 and 15 is raised to a temperature in the range of 650°C to 750°C, and typically, to a temperature of 700°C which causes the ink in the bands 14 and 15 to fuse with the glass of the pane 3, thereby effectively permanently securing the bands 14 and 15 to the pane 3. The glass is subjected to the toughening temperature of 700°C for a period of approximately one and a half minutes, upwards. Thereafter the pane 3 is cooled.

While the rate of cooling may have some effect on the toughening of the glass, it is not critical from the point of view of fusing the paint to the glass. Once the paint and glass have been raised to a temperature of approximately 700°C, the paint is fused to the glass, and thereafter all that is required is to cool the glass.

After the pane 3 has been cooled to room temperature, the pane 3 is assembled with the inner pane 2 to form the double glazed unit 1.

While specific drying and fusing temperatures have been described, it will be readily apparent to those skilled in the art that other drying and fusing temperatures may be used. It will also be appreciated that while it is preferable it is not essential that the pattern should be dried prior to fusing the pattern to the glass. The fusing could commence immediately the pattern had been applied to the glass. It will also be appreciated that while in this embodiment of the invention the fusing of the paint to the glass has been carried out simultaneously with a toughening process for toughening the glass, the pattern may be fused to the glass without necessarily toughening the glass.

While a specific mineral based ink has been described and a specific agglomerating agent has been described, other suitable mineral based inks may be used, as may other suitable agglomerating agents be used. While, in general, the agglomerating agent would be contained in the solvent, this is not essential. Other inks and solvents have already been described.

Additionally, while a specific construction of spray nozzle has been described, other suitable spray nozzles may be used, and needless to say, the paint may be pressurised to other pressures besides that described. Needless to say, the spacing of the spray nozzle from the surface to which the pattern is being applied may be varied, and indeed, would be varied depending on other variables in the airless spraying process.

While the pattern which has been applied to the glass pane has been described as being a pattern for simulating a Georgian style lattice, any other desired pattern could be applied without departing from the scope of the invention. It will be readily apparent to those skilled in the art that a Tudor style lattice could be simulated.

While the window pane has been described as being a double glazed unit, it will be readily apparent to those skilled in the art that the window pane could be provided as a single glazed window pane. In general, it is envisaged that it is preferable to locate the pattern on the inner side of the window pane.

While the glass panel has been described as being a window pane, it will be readily apparent to those skilled in the art that a pattern may be applied to any glass panel, be it a window pane or otherwise, and such a method and a glass panel would be within the scope of the invention.

Additionally, while the pattern has been described as being applied by a single spray nozzle, in certain cases, it is envisaged that more than one spray nozzle may be used, however, in general, it is believed desirable that for applying a band of the type used to simulate a Georgian or Tudor style lattice type window, a single spray nozzle with a single outlet jet of the type described is preferable, and in particular, a spray nozzle which outputs a flat fan shaped jet of the liquid ink. While specific dimensions of bore size and nozzle outlet have been described, it is envisaged that a spray nozzle of different dimensions could be used.

The invention is not limited to the embodiment hereinbefore described, which may be varied in construction and detail.

Claims (5)

1. A method for applying a pattern to a glass panel, the method comprising the steps of applying mineral based ceramic ink to the glass panel to form the pattern, wherein the mineral based ink is applied by airless spraying, and the mineral based ink comprises an agglomerating agent for agglomerating the molecules of the mineral based ink together.

2. A method as claimed in Claim 1 in which the mineral based ink is in powder form prior to mixing with the agglomerating agent, and the agglomerating agent is a solvent.

3. A method as claimed in Claim 1 or 2 in which the mineral based ink is applied by airless spraying through a nozzle having a circular bore, which converges in one plane for defining an elongated nozzle outlet, and diverges in a plane at right angles to the plane in which the bore converges, and the rate of diverging of the bore of the nozzle is such as to provide a jet of the mineral based ink to issue from the nozzle outlet in a fan shape of fan angle in the range of 5° to 40°.

4. A method for applying a pattern to a glass panel, the method being substantially as described herein with reference to and as illustrated in the accompanying drawings.

5. A glass panel having a pattern applied thereto by the method as claimed in any preceding claim. F.F. GORMAN & CO.