IE20030854A1

IE20030854A1 - A method for applying a pattern to a glass panel

Info

Publication number: IE20030854A1
Application number: IE20030854A
Authority: IE
Inventors: William Gerard Carey
Original assignee: Carey Brothers Ltd
Priority date: 2002-11-18
Filing date: 2003-11-14
Publication date: 2004-08-11
Also published as: GB2396843A; GB2396843B; IES20020887A2; GB0326833D0

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), although the surface coating composition may be applied up to a depth of 1,200 microns. The surface coating composition of the bands (14,15) 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. <Figures 1 & 3>

Description

“A method for applying a pattern to a glass panel ® °3 08 54 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. The invention further relates to a double glazed unit for a window.

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 simulated 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 each window pane is formed by a double glazed unit comprising two glass panels, namely, an inner glass panel and an outer glass panel 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 panels 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 panels, which typically, is 12mm. The width of the spacer 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 OPEN TO PUBLIC INSPECTION UNOER SECTION 28 ANL RULE 23 ’ JNLNol2S®£.____OF.^SS such spacer bars is that the spacer bars act as a cold bridge which conducts heat between the inner and outer glass panels of the double glazed unit, thus significantly increasing heat loss through the double glazed unit.

An alternative to the use of spacer bars in the simulation of Georgian and Tudor style lattice windows in double glazed units is to stick lead strips to one of the glass panels 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 undesirable.

It is also known to simulate Georgian and Tudor style lattice windows by painting the criss-cross members onto the glass panel. 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 crisscross 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. •Ε 0 3 08 5 4 The present invention is directed towards providing a method for applying a pattern to a glass panel and to a glass panel having a pattern applied thereto. The invention is also directed to a double glazed window unit.

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 surface coating composition to the glass panel to form the pattern, wherein the surface coating composition comprises a mineral based ink suitable for ceramics applications and an agglomerating agent for agglomerating the molecules of the mineral based ink together, and the surface coating composition is applied to the glass panel by airless spraying.

Preferably, the mineral based ink is in powder form prior to mixing with the agglomerating agent. Advantageously, the particle size of the mineral based ink powder is relatively small. Preferably, the particle size of the mineral based ink powder is in the range of 1 micron to 10 microns. Ideally, the particle size of the mineral based ink powder is in the range of 1 micron to 7.6 microns.

In one embodiment of the invention the mineral based ink comprises 2(2-butoxye thoxy) ethanol, lead cadmium.

In another embodiment of the invention the surface coating composition comprises a colour pigment for defining the colour of the pattern. ίΕ θ3 08 5 4 In a further embodiment of the invention the agglomerating agent is a solvent, and preferably, is selected from any one or more of the following solvents: diethylene glycol monobutyl ether, propylene glycol methyl ether, methoxy-1, 2-propanol, propylene glycol-1-methyl ether, methoxy-1, 2-hydroxpropane, and methyl propylene glycol.

In one embodiment of the invention the surface coating composition is applied by the airless spraying through a nozzle having a bore extending therethrough which converges in one plane in a downstream direction towards an outlet of the nozzle for defining the nozzle outlet as an elongated nozzle outlet.

In another embodiment of the invention the nozzle outlet defines a jet of the surface coating composition of substantially rectangular transverse cross-section.

Preferably, the nozzle outlet defines a jet of the surface coating composition of transverse cross-section having a transverse length which is considerably greater than the transverse width of the cross-section. Advantageously, the nozzle outlet defines a jet of the surface coating composition of transverse cross-section of transverse length which is at least five times the transverse width of the crosssection. Ideally, the nozzle outlet defines a jet of the surface coating composition of transverse cross-section of transverse length which is at least ten times the ,Ε°3 08 5 4 transverse width of the cross-section.

In a further embodiment of the invention the bore of the nozzle diverges in a downstream direction in a plane at right angles to the plane in which the bore converges for defining the nozzle outlet as an elongated nozzle outlet. Preferably, the bore of the nozzle diverges in a downstream direction at a rate which is such as to provide the jet of the surface coating composition to exit the nozzle outlet in a fan shape.

In one embodiment of the invention the bore of the nozzle diverges in a downstream direction at a rate which is such as to provide the jet of the surface coating composition to exit the nozzle outlet in a fan shape, the fan having diverging edges which diverge at an angle in the range of 5° to 90°, and preferably, in the range of ° to 90°, and advantageously, in the range of 30° to 90°, and more preferably, in the range of 30° to 60°. Ideally, the bore of the nozzle diverges in a downstream direction at a rate which is such as to provide the jet of the surface coating composition to exit the nozzle outlet in a fan shape, the fan having diverging edges which diverge at an angle of approximately 30°.

In another embodiment of the invention the length of the nozzle outlet is at least five times greater than the width of the nozzle outlet. Preferably, the length of the nozzle outlet is at least ten times greater than the width of the nozzle outlet.

Advantageously, the length of the nozzle outlet is at least fifteen times greater than the width of the nozzle outlet. ,e°J 08 54 In one embodiment of the invention an upstream portion of the bore of the nozzle is of circular transverse cross-section prior to the commencement of converging of the bore. Preferably, the circular upstream portion of the bore of the nozzle is of diameter in the range of 0.015mm to 0.25mm, and advantageously, in the range of 0.015mm to 0.175mm.

Preferably, one of the nozzle and the glass panel is moved relative to the other for applying the surface coating composition to the glass panel, the speed of relative movement between the nozzle and the glass panel being controlled for depositing the surface coating composition on the glass panel to a desired depth. Advantageously, the spacing of the nozzle outlet of the nozzle from the glass panel is selected to minimise feathering of edges defining the pattern.

In one embodiment of the invention the spacing of the nozzle outlet from the glass panel is selected for determining the transverse cross-sectional length of the jet of the surface coating composition impinging on the glass panel. Preferably, the nozzle outlet is spaced apart from the glass panel a distance in the range of 1mm to 40mm. Advantageously, the nozzle outlet is spaced apart from the glass panel a distance in the range of 10mm to 40mm. Ideally, the nozzle outlet is spaced apart from the glass panel a distance of approximately 20mm.

In one embodiment of the invention the surface coating composition is pressurised for the airless spraying thereof. Preferably, the surface coating composition is °s Οβ 5 4 pressurised at a pressure in the range of 40 bar to 300 bar for the airless spraying thereof. Advantageously, the pressure of the surface coating composition is controlled for depositing the surface coating composition on the glass panel to a desired depth.

In one embodiment of the invention the surface coating composition is deposited on the glass panel to a depth of at least 150 microns. Preferably, the surface coating composition is deposited on the glass panel to a depth of at least 175 microns. More preferably, the surface coating composition is deposited on the glass panel to a depth of at least 200 microns. Advantageously, the surface coating composition is deposited on the glass panel to a depth in the range of 200 microns to 1200 microns, and ideally, the surface coating composition is deposited on the glass panel to a depth in the range of 200 microns to 250 microns.

In another embodiment of the invention the glass panel with the surface coating composition forming the pattern thereon is subjected to a high temperature heat treatment for fusing the surface coating composition forming the pattern to the glass panel. Preferably, the glass panel with the surface coating composition forming the pattern thereon is subjected to the high temperature heat treatment at a temperature in the range of 650°C to 750°C.

In one embodiment of the invention the surface coating composition forming the pattern is fused to the glass panel during heat treatment of the glass panel for toughening thereof. /ε°ί0β54 In a further embodiment of the invention the glass panel is subjected to a low temperature heat treatment for drying the surface coating composition forming the pattern thereon prior to being subjected to the high temperature heat treatment.

Preferably, the glass panel with the surface coating composition forming the pattern thereon is subjected to the low temperature heat treatment at a temperature in the range of 90°C to 100°C. Advantageously, the low temperature heat treatment ofthe glass panel is carried out by infrared radiation.

In one embodiment of the invention the pattern is a criss-cross pattern for simulating a lattice type window.

In another embodiment ofthe invention the criss-cross pattern simulates a Georgian lattice type window. Alternatively, the criss-cross pattern simulates a Tudor lattice type window.

The invention also provides a glass panel having a pattern applied thereto, the pattern being applied to the glass panel by the method according to the invention.

In one embodiment of the invention the glass panel is a window pane.

In another embodiment of the invention the glass panel is one of a pair of glass panels of a double glazed window unit. £ 03Oo5 4 The invention also provides a double glazed window unit having an inner glass panel and a spaced apart outer glass panel, the outer glass panel having an inner surface facing an inner surface of the inner glass panel, a pattern being applied to the inner surface of one of the inner and outer glass panels by the method according to the invention.

In one embodiment of the invention the pattern is applied to the inner surface of the outer glass panel.

The invention will be more clearly understood from the following description of a preferred 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 on the line ll-ll 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 for applying a pattern to the double glazed window unit of Fig.

,E 0 3 08 5 4 1, Fig. 5 is a transverse cross-sectional side elevational view of the nozzle on the line V-V of Fig. 4, and Fig. 6 is a transverse cross-sectional end elevational view of the nozzle on the line VI-VI of Fig. 4, Fig. 7 is a diagrammatic side elevational view of the spray nozzle of Fig. 4 mounted relative to a glass panel of the double glazed window unit of Fig. 1 during spraying of the pattern onto the glass panel, and Fig. 8 is a diagrammatic top plan view of the spray nozzle and glass panel 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 glass panel 2, and an outer glass panel 3. The inner and outer glass panels 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 glass panels 2 and 3 between the respective glass panels 2 and 3 for spacing the panels 2 and 3 apart to form the cavity 4. A sealing band 7 extends around the periphery of the double glazed unit 1, and sealably engages the spacer member 6 and peripheral edges 8 and 9 of the inner and outer panels 2 and 3, respectively, for sealing the cavity 4. The inner panel 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, although it will be appreciated that it is not necessary for either of the panels to be of heat reflective glass.

A pattern 10 which in this embodiment of the invention simulates a Georgian style lattice window is applied to an inner surface 11 of the outer panel 3 within the cavity 4 prior to assembling the inner and outer panels 2 and 3 of the double glazed unit 1. io The method for applying the pattern 10 to the outer panel 3 comprises applying a surface coating composition, which forms the pattern, to the inner surface 11 of the outer panel 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 Wof 20mm, and the surface coating composition 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 14 and 15 are sharply defined, and are not feathered.

Turning now to the method according to the invention for forming the pattern 10, the surface coating composition comprises a mineral based ink in powder form which is mixed with an agglomerating agent in liquid form. A colour pigment in powder form is added to the mineral based ink as appropriate. In this embodiment of the IE invention the agglomerating agent is a solvent, namely, diethylene glycol monobutyl ether manufactured by Fluka Chemie GmbH of Bucks, Switzerland and supplied by Sigma Aldrich Chemie GmbH. Additionally, in this embodiment of the invention the bands 14 and 15 are white, and thus, the colour pigment is a suitable white pigment in powder form and is added to the mineral based ink prior to mixing with the solvent. The mineral based ink 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 sizes of the particles of the mineral based ink ranges from 1 micron to 7.6 microns. The solvent is mixed with the mineral based io ink in the proportion four parts by volume mineral based ink powder to approximately one part solvent and the mineral based ink and solvent are thoroughly mixed to form the surface coating composition for applying to the outer panel 3 by airless spraying.

Referring now to Figs. 4 to 8 the airless spraying of the surface coating composition onto the inner surface 11 of the outer panel 3 will now be described. The surface coating composition is pressurised to a pressure in the range of 40 bar to 300 bar, and typically, 140 bar, and is applied to the outer panel 3 by the airless spraying through a spray nozzle 20. The spray nozzle 20 defines a substantially rectangular shaped nozzle outlet 22 through which the pressurised surface coating composition is applied to the outer panel 3 to form the pattern 10. A bore 23 extends through the spray nozzle 20 from an upstream end 24 to a downstream end 25 where it terminates in the nozzle outlet 22 for accommodating the pressurised surface coating composition therethrough. An upstream portion 27 of the bore 23 extends to a position 28, and is of circular transverse cross-section of diameter D of IE °3 08 5 4 approximately 7 microns. A downstream portion 30 of the bore 23 converges in a plane 31 in a downstream direction from the position 28 to the nozzle outlet 22 and defines long edges 33 of the nozzle outlet 22. Additionally, the downstream portion 30 of the bore 23 diverges in a plane 34, which is at right angles to the plane 31, from the position 28, in a downstream direction to the nozzle outlet 22 for defining short edges 35 of the nozzle outlet 22. The long edges 33 and the short edges 35 define the substantially rectangular shape of the nozzle outlet 22. In this embodiment of the invention the transverse length L of the nozzle outlet 22 along the plane 34 is approximately 2mm, while the width t of the nozzle outlet 22 along the plane 31 is approximately 0.12mm. The angle at which the downstream portion 30 of the bore 23 diverges in the plane 34 is such as to form a jet 36 of the surface coating composition to issue from the nozzle outlet 22 with an included fan angle a of approximately 30°, see Fig. 7.

A jig (not shown) is provided for supporting the outer panel 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 36 of the surface coating composition to the inner surface 11 of the outer panel 3 so that the jet 36 is directed vertically downwardly and perpendicular to the inner surface 11. The numerically controlled carrier urges the spray nozzle 20 at an appropriate speed relative to the inner surface 11 of the outer panel 3, which is set depending on the pressure to which the surface coating composition is pressurised, so that the surface coating composition is deposited to a depth d of 200 microns on the inner surface 11 for forming the bands 14 and 15. ,ε 0 3 08 5 4 Additionally, the spacing of the nozzle outlet 22 above the inner surface 11 of the outer panel 3 is set at a distance S, 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 fan angle a of 30° and the pressure set at approximately 140 bar, the optimum spacing S between the nozzle outlet 22 and the inner surface 11 is approximately 20mm. It has also been found that if the distance S between the nozzle outlet 22 and the inner surface 11 is too close, the jet 36 on impinging against the inner surface 11 rises what is effectively a bow wave on its leading edge, which can cause distortion ofthe bands, particularly when one ofthe io bands, for example, one ofthe vertical bands 15 is crossing over an already applied horizontal band 14. If the distance S is too great, it has been found that over-spray commences, thus leading to feathering ofthe edges 16 ofthe bands 14 and 15.

Referring now to Fig. 8, the width IV of the bands 14 and 15, as well as being determined by the distance S between the nozzle outlet 22 and the inner surface 11 is also determined by angling the nozzle outlet 22 relative to a central axis 38 of the bands 14 and 15, so that the plane 34 defined by the nozzle 20 makes an angle φ with the central axis 38. In this embodiment of the invention since the bands 14 and are to be of width approximately 20mm, the angle φ is approximately 45°. Where it is desired to form a wider band than the bands 14 and 15, the angle φ is appropriately increased. To form a narrower band the angle φ 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 nozzle 20 is oriented relative to the central axis 38 until the angle φ is approximately zero.

In other words, the nozzle 20 is oriented relative to the central axis 38 defined by the band so that the plane 34 defined by the nozzle 20 and the central axis 38 defined by the band substantially coincide with each other.

The numerically controlled carrier (not shown) urges the spray nozzle 20 at an appropriate speed relative to the inner surface 11 of the outer panel 3 for forming the vertical bands 15 first, and when the vertical bands 15 have been formed, the numerical controlled carrier (not shown) then similarly urges the spray nozzle 20 relative to the inner surface 11 of the outer panel 3 for forming the horizontal bands 14.

After the bands have been formed on the outer panel 3, the outer panel 3 is subjected to a low temperature infrared radiation heat treatment for drying the surface coating composition forming the bands 14 and 15. The low temperature heat treatment is carried out at a temperature in the range of 90°C to 100°C for a time period of approximately ten minutes for drying the surface coating composition.

After drying, the outer panel 3 is then placed in a toughening oven for toughening of the glass of the outer panel 3. The temperature of the outer panel 3 and the surface coating composition of the bands 14 and 15 is raised to a temperature in the range of 650°C to 750°C, and typically, to a temperature in the order of 700°C, which as well as toughening the glass of the outer panel 3 also causes the surface coating composition of the bands 14 and 15 to be fused with the glass of the outer panel 3, thereby effectively permanently securing the bands 14 and 15 to the outer panel 3. /e 0 3 08 5 4 The outer panel 3 is subjected to the toughening temperature of 700°C for a period of approximately one and a half minutes, upwards. Thereafter the outer panel 3 is cooled. While the rate of cooling may have an effect on the toughening of the glass, it is not critical from the point of view of fusing the surface coating composition of the bands 14 and 15 to the glass of the outer panel 3. Once the surface coating composition of the bands 14 and 15 and the glass have been raised to a temperature of approximately 700°C, the surface coating composition is fused to the glass, and thereafter all that is required is to cool the outer panel 3.

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

The advantages of the invention are many. By virtue of the fact that the pattern is formed on the outer panel to a reasonable depth, in the order of 200 microns without feathered edges provides a window pane which effectively simulates a Georgian or Tudor style window. It is believed that the absence of feathering on the edges of the pattern is achieved by applying the surface coating composition by airless spraying. It is believed that conventional air spraying could lead to feathering of the edges of the pattern as a result of air entrained in the surface coating composition when impinging on the glass panel. It is also believed that the provision of the mineral based ink in the surface coating composition, and in particular the provision of the agglomerating agent in the surface coating composition also assists in providing the pattern with sharp unfeathered edges. The agglomerating agent assists in binding the molecules of the mineral based ink, thereby minimising any danger of feathering /e 0 3 08 5 4 of the edges. The provision of the agglomerating agent as a solvent further assists in the absence of feathering of the edges of the pattern.

By providing the mineral based ink of the type which is suitable for ceramic applications also assists in providing the pattern with edges in which feathering is absent.

By providing the mineral based ink in powder form with particles of size in the range of 1 micron to 10 microns permits the surface coating composition to be applied to a reasonable depth in one application of the surface coating composition. Indeed, by providing the mineral based ink to be of particles of sizes in the range from 1 micron to 7.6 microns permits the surface coating composition to be applied to the panel to a depth of approximately 200 microns in one application. Additionally, providing the mineral based ink of the surface coating composition to be of such particle size also, it is believed, facilitates in avoiding feathering of the edges of the pattern.

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 surface coating composition forming 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 surface coating composition to the glass has been carried out simultaneously with a toughening process for toughening the glass, the surface * 0 J 5f coating composition may be fused to the glass without necessarily toughening the glass.

While the surface coating composition has been described as comprising a specific 5 mineral based ink, it is envisaged that other suitable mineral based inks may be used. However, it is desirable that the mineral based ink should be suitable for ceramics applications, and also suitable for fusing with the glass panel. Additionally, it is desirable that the mineral based ink should be provided in powder or particulate form of particle size not less than 1 micron, and preferably, the particle size should be in the range of 1 micron to 7.6 microns.

It is also envisaged that other suitable agglomerating agents may be used besides a solvent, and where a solvent is used as the agglomerating agent, other suitable solvents besides that described may be used, for example, another suitable solvent is a solvent sold by Shell Chemicals under the trade name Methyl PROXITOL, particulars of which are set out in the Data Sheet No. IS 3.4.1 A of Shell Chemicals.

While the colour pigment has been described as being a white colour pigment, the colour pigment selected will depend on the desired colour of the pattern to be applied to the glass panel.

Additionally, while a specific construction of spray nozzle has been described, other suitable spray nozzles may be used, and needless to say, the surface coating composition may be pressurised during the airless spraying 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. Additionally, it is envisaged that the nozzle may be provided in order to provide jets of the surface coating composition issuing therefrom of included fan angles other than 30°. It is also envisaged that the bore of the spray nozzle and the nozzle outlet may be of oval cross-section.

While the nozzle outlet has been described as being of length greater than its width, in certain cases, it is envisaged that the nozzle outlet may be of circular transverse cross-section, or may be of square transverse cross-section. Indeed, in certain cases, particularly when forming a Tudor type pattern, it is envisaged that the nozzle outlet may be of either circular or square transverse cross-section.

While the pattern which has been applied to the glass panel 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 pattern could be simulated by the method according to the invention just described.

While the glass panel has been described as being one of the glass panels of a double glazed unit, it will be readily apparent to those skilled in the art that the glass panel could be provided for use as a single glazed window pane. In general, it is envisaged that it is preferable to locate the pattern on the side of the glass panel 0 ί Og 5 4 which in use forms the inner side of a single glazed 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 nozzle outlet of the type described is preferable, and in particular, a spray nozzle which outputs a substantially single plane fan shaped jet of the surface coating composition. While specific dimensions of bore size and nozzle outlet size have been described, it is envisaged that a spray nozzle of different dimensions could be used.

While the depth of the surface coating composition applied to the glass panel has been described as being 200 microns, it is envisaged that the surface coating composition may be applied to the glass panel to any desired depth, and indeed, it is envisaged that the surface coating composition may be applied to the glass panel to a depth of up to 1,200 microns, and in certain cases, even to greater depths.

Claims

1. A method for applying a pattern to a glass panel, the method comprising the steps of applying a surface coating composition to the glass panel to form the pattern, wherein the surface coating composition comprises a mineral based ink 5 suitable for ceramics applications and an agglomerating agent for agglomerating the molecules of the mineral based ink together, and the surface coating composition is applied to the glass panel by airless spraying.

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

3. A method as claimed in Claim 2 in which the particle size of the mineral based ink powder is relatively small. 15

4. A method as claimed in Claim 3 in which the particle size of the mineral based ink powder is in the range of 1 micron to 10 microns.

5. A method as claimed in Claim 4 in which the particle size of the mineral based ink powder is in the range of 1 micron to 7.6 microns.

6. A method as claimed in any preceding claim in which the mineral based ink comprises 2(2-butoxye thoxy) ethanol, lead cadmium.

7. A method as claimed in any preceding claim in which the surface coating /ε Oq 5 4 composition comprises a colour pigment for defining the colour of the pattern.

8. A method as claimed in any preceding claim in which the agglomerating agent is a solvent.

9. A method as claimed in Claim 8 in which the solvent forming the agglomerating agent is selected from any one or more ofthe following solvents: diethylene glycol monobutyl ether, propylene glycol methyl ether,

10. Methoxy-1,2-propanol, propylene glycol-1-methyl ether, methoxy-1,2-hydroxpropane, and methyl propylene glycol. 15 10. A method as claimed in any preceding claim in which the surface coating composition is applied by the airless spraying through a nozzle having a bore extending therethrough which converges in one plane in a downstream direction towards an outlet ofthe nozzle for defining the nozzle outlet as an elongated nozzle outlet.

11. A method as claimed in Claim 10 in which the nozzle outlet defines a jet of the surface coating composition of substantially rectangular transverse crosssection. 03 08 5 4

12. A method as claimed in Claim 10 or 11 in which the nozzle outlet defines a jet of the surface coating composition of transverse cross-section having a transverse length which is considerably greater than the transverse width of the cross-section.

13. A method as claimed in any of Claims 10 to 12 in which the nozzle outlet defines a jet of the surface coating composition of transverse cross-section of transverse length which is at least five times the transverse width of the crosssection.

14. A method as claimed in Claim 13 in which the nozzle outlet defines a jet of the surface coating composition of transverse cross-section of transverse length which is at least ten times the transverse width of the cross-section.

15. 15. A method as claimed in any of Claims 10 to 14 in which the bore of the nozzle diverges in a downstream direction in a plane at right angles to the plane in which the bore converges for defining the nozzle outlet as an elongated nozzle outlet. 20

16. A method as claimed in Claim 15 in which the bore of the nozzle diverges in a downstream direction at a rate which is such as to provide the jet of the surface coating composition to exit the nozzle outlet in a fan shape.

17. A method as claimed in any of Claims 15 or 16 in which the bore of the 0 3 08 5 4 nozzle diverges in a downstream direction at a rate which is such as to provide the jet of the surface coating composition to exit the nozzle outlet in a fan shape, the fan having diverging edges which diverge at an angle in the range of 5° to 90°. 5

18. A method as claimed in Claim 17 in which the bore of the nozzle diverges in a downstream direction at a rate which is such as to provide the jet of the surface coating composition to exit the nozzle outlet in a fan shape, the fan having diverging edges which diverge at an angle in the range of 10° to 90°. 10

19. A method as claimed in Claim 18 in which the bore of the nozzle diverges in a downstream direction at a rate which is such as to provide the jet of the surface coating composition to exit the nozzle outlet in a fan shape, the fan having diverging edges which diverge at an angle in the range of 30° to 90°. 15 20. A method as claimed in Claim 19 in which the bore of the nozzle diverges in a downstream direction at a rate which is such as to provide the jet of the surface coating composition to exit the nozzle outlet in a fan shape, the fan having diverging edges which diverge at an angle in the range of 30° to 60°.

20

21. A method as claimed in Claim 20 in which the bore of the nozzle diverges in a downstream direction at a rate which is such as to provide the jet of the surface coating composition to exit the nozzle outlet in a fan shape, the fan having diverging edges which diverge at an angle of approximately 30°. IE 0 3 Οβ 54

22. A method as claimed in any of Claims 10 to 21 in which the length of the nozzle outlet is at least five times greater than the width of the nozzle outlet.

23. A method as claimed in Claim 22 in which the length of the nozzle outlet is at 5 least ten times greater than the width of the nozzle outlet.

24. A method as claimed in Claim 23 in which the length of the nozzle outlet is at least fifteen times greater than the width of the nozzle outlet. 10

25. A method as claimed in any of Claims 10 to 24 in which an upstream portion of the bore of the nozzle is of circular transverse cross-section prior to the commencement of converging of the bore.

26. A method as claimed in Claim 25 in which the circular upstream portion of the 15 bore of the nozzle is of diameter in the range of 0.015mm to 0.25mm.

27. A method as claimed in Claim 26 in which the circular upstream portion of the bore of the nozzle is of diameter in the range of 0.015mm to 0.175mm. 20

28. A method as claimed in any of Claims 10 to 27 in which one of the nozzle and the glass panel is moved relative to the other for applying the surface coating composition to the glass panel, the speed of relative movement between the nozzle and the glass panel being controlled for depositing the surface coating composition on the glass panel to a desired depth. ,Ε ο J 08 5 4

29. A method as claimed in any of Claims 10 to 28 in which the spacing of the nozzle outlet of the nozzle from the glass panel is selected to minimise feathering of edges defining the pattern.

30. A method as claimed in any of Claims 10 to 29 in which the spacing of the nozzle outlet from the glass panel is selected for determining the transverse crosssectional length of the jet of the surface coating composition impinging on the glass panel. io

31. A method as claimed in any of Claims 10 to 30 in which the nozzle outlet is spaced apart from the glass panel a distance in the range of 1mm to 40mm.

32. A method as claimed in Claim 31 in which the nozzle outlet is spaced apart 15 from the glass panel a distance in the range of 10mm to 40mm.

33. A method as claimed in Claim 32 in which the nozzle outlet is spaced apart from the glass panel a distance of approximately 20mm. 20

34. A method as claimed in any preceding claim in which the surface coating composition is pressurised for the airless spraying thereof.

35. A method as claimed in Claim 34 in which the surface coating composition is pressurised at a pressure in the range of 40 bar to 300 bar for the airless spraying Ο 3 Ο 8 5 < thereof.

36. A method as claimed in Claim 34 or 35 in which the pressure of the surface coating composition is controlled for depositing the surface coating composition on 5 the glass panel to a desired depth.

37. A method as claimed in any preceding claim in which the surface coating composition is deposited on the glass panel to a depth of at least 150 microns. 10

38. A method as claimed in Claim 37 in which the surface coating composition is deposited on the glass panel to a depth of at least 175 microns.

39. A method as claimed in Claim 38 in which the surface coating composition is deposited on the glass panel to a depth of at least 200 microns.

40. A method as claimed in Claim 39 in which the surface coating composition is deposited on the glass panel to a depth in the range of 200 microns to 1200 microns.

41. A method as claimed in Claim 40 in which the surface coating composition is 20 deposited on the glass panel to a depth in the range of 200 microns to 250 microns.

42. A method as claimed in any preceding claim in which the glass panel with the surface coating composition forming the pattern thereon is subjected to a high temperature heat treatment for fusing the surface coating composition forming the IE °3 08 54 pattern to the glass panel.

43. A method as claimed in Claim 42 in which the glass panel with the surface coating composition forming the pattern thereon is subjected to the high temperature 5 heat treatment at a temperature in the range of 650°C to 750°C.

44. A method as claimed in any preceding claim in which the surface coating composition forming the pattern is fused to the glass panel during heat treatment of the glass panel for toughening thereof. io

45. A method as claimed in any of Claims 42 to 44 in which the glass panel is subjected to a low temperature heat treatment for drying the surface coating composition forming the pattern thereon prior to being subjected to the high temperature heat treatment.

46. A method as claimed in Claim 45 in which the glass panel with the surface coating composition forming the pattern thereon is subjected to the low temperature heat treatment at a temperature in the range of 90°C to 100°C. 20

47. A method as claimed in Claim 45 or 46 in which the low temperature heat treatment of the glass panel is carried out by infrared radiation.

48. A method as claimed in any preceding claim in which the pattern is a crisscross pattern for simulating a lattice type window. ,E 03 08 54

49. A method as claimed in Claim 48 in which the criss-cross pattern simulates a Georgian lattice type window. 5

50. A method as claimed in Claim 48 in which the criss-cross pattern simulates a Tudor lattice type window.

51. 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 10 accompanying drawings.

52. A glass panel having a pattern applied thereto, the pattern being applied to the glass panel by the method as claimed in any preceding claim. 15

53. A glass panel as claimed in Claim 52 in which the glass panel is a window pane.

54. A glass panel as claimed in Claim 52 or 53 in which the glass panel is one of a pair of glass panels of a double glazed window unit.

55. A glass panel substantially as described herein with reference to and as illustrated in the accompanying drawings.

56. A double glazed window unit having an inner glass panel and a spaced apart IE 0 3 08 5 4 outer glass panel, the outer glass panel having an inner surface facing an inner surface of the inner glass panel, a pattern being applied to the inner surface of one of the inner and outer glass panels by the method as claimed in any of Claims 1 to 51.

57. A double glazed window unit as claimed in Claim 56 in which the pattern is applied to the inner surface of the outer glass panel.

58. A double glazed window unit substantially as described herein with reference 10 to and as illustrated in the accompanying drawings.