CA2177995A1 - Method for producing decorated glass panels - Google Patents

Abstract

A method of making decorated glass panels, particularly glass panels decorated with designs to simulate stone such as marble, is described. Water-slide transfers (10) are formed by printing designs simulating marble on a backing of gummed paper with an ink of glass frit and coloured metal oxides in a printing medium. Several transfers (10) are soaked in water and then removed from their backing and placed in overlapping relationship on a panel of glass (15). The transfers are cut through in the region of their overlap (16) and the surplus material removed. After drying the panel is passed through a furnace to burn off the printing medium. A coating of ceramic or vitreous enamel material (25) is applied over the design and the panel is then subjected to a second heat treatment cycle in which the glass frits and metal oxide fuse to the glass panel, the coating is baked on to the panel and the glass is toughened by rapidly heating in a furnace and then cooling.

Description

WO 95/lS267 ~17 ~ PCT/GB9~102616 Method for produc~ng decorated glass panels The present invention relates to a mcthod for S making decorative glass panela, particularly but not exclusively gla8s panels that aimulate panels of marble, granite or other stone, or other types of grained material 8uch as leather or wood.
It i~ common practice to use panels of marble or other stone for cladding walls of building3, either internally or ~Yt~rn7~ly. Marble is an expensive material and where it is desired to clad a large building it can be difficult to find enough of a 15 sufficiently uniform colour. Wood and simulation wood pAn~.llin~ and leather or leatherette pAn~llin~ is also used for facing items such as elevators, and furniture.
The method of the present invention may be used for 20 producing glass panels which look like marble and can be used in applications, 8uch as cladding b~ nsJ~ where marble or other stone or other materials might have been used .
According to the present invention in a first aspect, there i8 provided a method for producing a decor~ted glass panel comprising applying a design to one side of the glass panel a5 a water-slide transfer, the transfer compri5ing the design in vitreous enamels, su'ojecting the glass panel with the applied transfer to a glass-~ou~h~nin~ heat treatment cycle, and including the step of applying a layer of material on the same W0 95/1~267 2 i ~ PCT/GB94/02616 .

side of the glass panel as the transfer, whereby the decorative effect is created by the design and the layer of material.
The layer of material may be a layer of pigmented material a~d may be opague, semi-opacue, translucent or transparent material. In a practical ' - 'J t the layer is of solid u~iform colour. In this context the word 'colour' includes white.

In one preferred form the layer of material is applied over the design. When viewed from the side of the glass opposite the side to which the design and covering layer are applied, the panel will create a decorative effect which depends on the ~ature of the desig~ applied to the glass and of the covering layer applied. The colour of the covering layer should be chosen to suit the colouring of the design in order to produce the desired decorative effect.
The design of the transfer may represent the fine detail for creati~g the desired fi~ished decorative effect, such as the graining of marble or other stone or of other material such as leather or wood. The layer of material produces the overall background colour.
The tranafer may be produced in the manner described in my patent Rpe~ ~ic~tior~ GB-A-2174383A.
When produciIlg a design that simulate8 marble, granite or other stone, a photograph of a piece of ~atural stone may be prepared and the trar~8fer produced from the ~ WO 9511S267 2 1 ~ 7 ~ 9 5 p~"~ 11A~ 6 photograph by a known colour printing techni~ue, using a mixture of glaGs ~rit3 and coloured metallic oxides in a printing mcdium aa the printing ink. The choice of colours and types o~ metallic oxides may have to be 5 adapted to allow for the change5 in colour that take place during the firing process.
The layer of material may simply be a layer o~
paint, or a layer of ceramic or vitreous enamel material 10 or other r~ ~ ter9 material . If paint i9 used it i8 preferred that a two-part epoxy reain based paint be used .
The pre~erred covering is however a layer of ceramic or 15 vitreous enamel material that is applied as a suspension by spraying, painting or roller. Preferably the glass panel is subjected to a g1a~s-~ h~n~n~ heat treatment cycle a~ter the ceramic coverirg has been applied. The panel may be sub; ected to a single ~iring process af ter 20 both the design and the covering layer have been applied, or to a double ~iring process: a ~irst heat treatment cycle af ter the design has been applied and a second heat treatment cycle af ter the covering has been applied. The second cycle is a glas8-tov~h~nin~ cycle.
25 The ~irst cycle may also be a glass-~ h~n;n~ cycle or it may be a cycle at a lower temperature without the rapid cooling required to produce t~ hinin~. The temperature of the first cycle may be only sufficient to burn of ~ the printing medium and any cover coat of the 30 transfer without causing fusing of the glass frit.
If the layer o~ covering material is paint, the WO 95/1~267 217 7 9 ~ 5 PCTIGB94/02616 . .

panel may be subjected to the gla3s-tou~h~n;n3 cycle before the layer of paint i3 applied and no further heat treatment may be necessary. If the paint is of the epoxy resin type it may be preferred to subiçct the 5 panel to a heating up to say lSO'C in order to accelerate the curing process. ``
The layer of material may also be formed by applying a layer of sheet material over the transfer O after the transfer has been subjected to the glas~-~n11~h~n~ns heat treatment cycle. An adhesive-backed plastics sheet material, for example the material sold under the T ' h FABLON is suitable for thi3 purpo:;e.
Such materials are suitable for appli~ nnn where the lS gla~s panel will be used indoor3.
For building applications panels of variou8 sizes may be required. It may not be practical to produce transfers in different sizes up to the size of the 20 largest panels required. In order to produce the larger panels several transfera may be used on a single panel of gla3s. The transfers may bear i~l~.n1-~ 1 designs.
According to the present invention in a second 25 aspect, transfers are applied to a glass panel with their edges overlapping one another. ~Che transfers are cut through in the region of the overlap along a line which follows the edge of a feature of the design, nnd the surplus portions of the transfers are removed. In 30 this way, a ~oint i8 formed between the ad~acent transfers can be formed which is not noticeable in the finished product, and the effect of an obvlous repeat WO 95/15267 r~.,~ 11S`~16 217799~
s pattern, which would result from using transfers with a pattern where one edge i3 designed to match up with the opposite edge, is avoided.
S An example of how the invention may be pe~ ' in practice will now be described with reference to the accompanying diagrammatic drawings, in which:
Figure 1 shows a perspective view of a water slide transfer used in a method according to the present invention;
Figure 2 shows a plan view of a glass panel with transfers being applied according to the method of the present invention;
Figure 3 shows a plan view on an enlarged scale of the panel of Figure 2 with the transfers being cut;
Figures 4 and 5 shows perspective view of the panel of Figure 3 with surplus material being removed from the transfers;
Figure 6 shows a perspective view of a covering being applied to the panel;
Figure 7 shows in schematic form the panel being passed through a furnace during the ~oll~h~n;ng cycle; S
and Figure 8 shows a cross section through the finished panel .

WO 95/lS267 21~ 7 ~ ~ ~ 6 - PCT/GB94/02616 Water-slide transfers 10 bearing a coloured de3ign are prepared a3 follow3. A~ photograph of a piece of marble i3 prepared and u3ing conventional printing technique3, the photograph is u3ed to prepare screen3 5 for a multi-tone or multi-colour printing of transfer3.
The design o~ the tran3~er reproduce3 the fine detail of the grained effect of the marble.
Referring to Figure 1, the de3ign 13 i3 printed on the gummed 3ide 11 of a backing sheet of gummed paper 12 using a screen printing technique. The areas of different tones or colours are built up in separate stage3 u3ing different 3creenD to build up the complete design. The colours are made up of lead-bearing glaa3 lS frit mixed with metallic oxides to give colour, and carried in a printing medium. The gla33 frit i3 made from a mixture of lead oxide, boric acid and 3ilica which i3 fused together and then quenched in water and dried. The frit i3 ground with metallic oxide o 20 the de3ired colour and then mixed with ju3t 3ufficient medium to enable it to be printed. The medium ha3 to be burnt of f during the heat treatment and the le33 medium that has to be burnt, the better the re3ult3 . The printing medium may be c~ l o~e or 25 re3inou3 and 3erve to bind the colour3 together.
Af ter the colour3 have been printed on the gummed paper the coloured areas 13 are covered with an acrylic re3in cover coat 14 to protect the tran3fer during 30 tr~n3port and handling.
When it is de3ired to produce a gla33 panel bearing o WO 95/15267 21 7 7 9 ~ 5 PCTIGB94/02616 the design, sufficient transfers 10 to cover the panel are soaked in clear water until each transfer is 1003ened from the gu~med-paper backing sheet 12. The transfers 10 are peeled from their backing sheets and 5 laid on one side of the glass panel 15 80 that each transfer overlaps the adjacent transfer (see Flg 2).
The glass panel 15 may be up to, say, 4.5 metres x 2.~
mctres in ~; n;~n~, The tranafer3 may conveniently be up to, say, 900 mm x 600 m~ 80 that 25 or more 10 transfers may be required to cover a single panel. The overlap 16 of transfer3 may be 25 to 100 mm, usually 30 to 40 m~. The maximum size of panel that can be used depends on the size of the furnace in which the heat treatment is performed. The size of the transfers i5 15 chosen for convenience of handling and versatility of application .
Once the transfer3 10 have been laid in place, and the surplus water removed, the transfers are cut with a 20 craft knife 17 in the region 16 of the overlap along a line 18 that follows the edges major features on the design (see Fig 3). With a marbled pattern the line may follow the boundary between aroas of sharply contrasting tone. It may be helpful if the pattern of the design 25 gradually fades towards the edge of the transfer. Once a line has been cut along the edge of each transfer, the ~urplus piece 19 of the upper layer of the overlapping transfers (Fig 2) is removed. Then the L~ ;nin~
adjacent edge 20 of the transfer is peeled back to 30 reveal the surplus portion 21 of the underlying layer of the ad~acent transfer, which is removed (Fig 5) before the peeled back portion is replaced. Once all W0 95/1~267 2 ~ 7 7 9 ~ ~ - 8 - I ~,II~L, 1!"~i16 overlapping parts have been removed, and the trimmed edges of the transfers abut one another the transfers are allowed to dry for several hours before undergoing a first heat treatment cycle.
In the first heat treatment cycle the glass with the applied transfer are passed slowly through a furnace where the panel is heated to a temperature of approxi=ately 450C. At this temperature the acrylic lO resin cover co~t 14 and the printing medium are burnt off in the ~Y;~liqin~ ai ,' 6 of the furnace, leaving the glass frit and metallic oxide undisturbed on the ~urface of the glass panel. The temperature does not have to be sufficiently high to fuse the glass frit lS during this preliminary treatment cycle. The duration of the preliminary heat treatment cycle can be tyoically 25 minutes to l hour, although in some cases the time could be less.
After being heated in the furnace, the panel 15 is allowed to cool. A coating of ceramic or vitreous enamel material 22 of suitable colour, for example white, is then applied to the same side of the glass as the transfer so as to cover the glass frit and metallic oxide layer. Pre~erably the ceramic or vitreous enamel layer is applied as a paint-like sl~arnnninn by spraying (Fig 6) and allowed to dry.
When the ceramic or vitreous enamel layer is dry 3 0 the panel is sub; ected to a second heat treatment cycle which i5 a glass tou~hnn~n~ cycle (Fig 7). In this second cycle the panel is heaced rapidly. The WO 95115267 ~ 1 7 7 ~ g 5 P ~, i . A , ..~, 6 ~ , g _ temperature of the burners in the furnace i8 typically 700-750C and the tempcrature of the panel reaches 620-670'C The glasa paaaes back and forth within the furnace 23 until it reachca the deaired temperature.
5 The glaas frit and metal oxide fuse to form areas 24 of colour that are fuacd to the surface of thQ glass. The coramic or vitreous cnamel layer is baked over aurface of the design to form a hard protective layer 25 which enhances the appearance of the design when viewed from 10 the opposite side.
The glass panel remain8 in the furnace 23 for 3 minutea or lesa, preferably 2 to 3 minutes. The treatment depends on the th~ rkn~.n~ of glaaa used which 15 may typically be from 4 mm to 25 mm. When the panel emergea from the furnace it is blaated with cold air from ~eta 30 to cauae rapid cooling of the suriace of the glaaa aD.d ron~ nt toll~hon;nJ of the glaas panel.
The panels produced by the method described above Are of tr~l~h~n~ glasa suitable for uae aa cladding material for b~ nrj~ and other application. The colours are resiatant to wear And fading. The panels 80 formed may oe lighter than slaba of 8tone uaed for the aame purpoae.
;3y auitable choicea of colours of L. ~ y~ .lt, semi-transparent and opaque enamels and for the covering of ceramic material various effects may be achieved ~nrlllr7in~ an effect of simulated marble.
The glass frits coaleace when they are melted and W0 95/1~67 PCT/G 4/026 2l77g95 B9 16 the joints between adjacert transfers become _L.-~tible when the panel has been throuyh all the processing stages. 'rhe surface that is outermost in use has a perfect polish because it is the untreated side of 5 the glas8.
Where it is desired to produce panels with bevelled or mitred edge3 or drilled holes for mounting, these oper~tions are performed prior to the tn~h~n;n~
lO cycle.
Although the invention has been described in relation to producing a m~rble effect panel, the effect other types of stone or other materials such as wood or 15 leather can be produced using the i~vention by suitable choice of designs and colours. It may also be used with other types of pictori~l or patterned designs.
An important Arpl~rAt-;nn for panels made in 20 accoLd ~ with the invention is cladding buildings both internally and ~ytArnAl ly. It may however be used for pAn~llinrj in other applications guch as for example shower cubicle door8, partitions, room doors, cupboard doors .
Although a covering of ceramic or vitreous material is placed over the design in the: ' ~ '; t described above, it may be omitted in some ~rpl~rAt~rn~, for example shower doors, where it may be preferred to use 30 transparent and semi- LLO~ Iellt colours for the transfer 80 that the finished panel permits some tr~n~m; ~irn of light.

~ WO9511S267 ~177~5 1~ i1fi In the preferred: ' ' t described the coating of ceramic or vitreous enamel i9 laid over the deaign on transfers. Alternatively the coating may be applied to the glaas panel firat and the decorative pattern in the 5 form of transfera may be applied over the ceramic or vitreous enamel layer afterward.
In the method deacribed above, the preliminary heat 20 treatment cycle involvea gentle heating to 450-. It lO may be preferred to carry out the preliminary heating using the same furnace as for the second heat treatment cycle. For example the glasa may be heated to 550 for up to 3 minutes and cooled rapidly af terwards . Such a cycle would be sufficient to fuse the glaaa frits onto 15 the surface of the glasa.
Although the whole of the surface of the glass is shown to be covered with trans~ers in the: ' '~-- t described above, the invention may be applied to only 20 part of the ~urface.
In the ~ t the transfer is made using a screen printing terhn~r,~ . other ~rhnir~ could be employed. For example a layer of printing medium or 25 varnish could be applied to the gu~med paper in the desired pattern and then dusted with a powder of glass frits and oxide 80 that the powder adheres to the areas where the printing medium has been applied. The process may be repeated with other colours of powder to build up 30 the desir~n.
AG can be 3een from the drawings, the design on the 21779~5 transfer repreaent the fine deeail of the finished article. In the case of simulated marble r~nol1;n~, the design represents the grained effect of the natural stone. Where it is desired to produce a panel that 5 ~ ~ ~ ' lol~ some other material a transfer is produced that ~Odl cc3 the fine detail of that other material and a covering layer of material of a colour appropriate for the desired material is uaed~
Although in the: ' t described above the cover coat i8 burnt off by pre-firing before the panel is subjected to the glass-to--ghoni"s cycle, this pre-f iring operation may be avoided by using a~ cover coat that can be removed -h~nioJ-lly, for example by 15 peeling, after the transfer has been applied to the glass. By using a material for the cover coat which is released ~rom the rest of the transfer by subjecting it to infrared radiation or by gentle heating, the cover coat can be removed without pre-firing. The transfer 20 can then be overprinted with a layer of ceramic material to form the background colour. The resulting panel can then be ~ubjected to a single glass-tou~hon;"~ heat treatment cycle which fuses the glass frit of the transfer and the ceramic layer in a single operation.
In another method according to the invention, the cover coat i8 removed using jets of water. After the transfer has been laid on the gla~ and dried, the glass frits and printing medium stick to the glass becau~e of the 30 gum on the backing paper. By using suitable materials for the cover coat it can then be removed by directing j ets of water onto the panel .

~ W095/lS267 2177~95 r~ .. "A?~516 Where it is r,ecseesy to use more than one transfer to cover a panel, the transfers 3hould preferably be overlapped, cut in the region of the overlap and the ,. -surplus removed. Por ~arbled effects auch as described 5 above, the cut may follow a meandering line, but for other effects such as wood veneer a staraight or u3iformly curved line may be appropriate.
Although the process described above uses water-slide 10 tra~sfers, other forms of transfers such as heat-release transfers "lay be used.

Claims (16)

C L A I M S:

1. A method for producing a decorated glass panel comprising applying a design to one side of the glass panel as a transfer, the transfer comprising the design in vitreous enamels, subjecting the glass panel with the applied transfer to a glass-toughening heat treatment cycle, and including the step of applying a layer of material on the same side of the glass panel, the decorative effect of the panel being created by viewing the layer of material through the design.

2. A method according to Claim 1, in which the layer of material is applied over the design.

3. A method according to claim 1 in which the layer of material is applied as a uniform layer prior to the application of the transfer, and in which the transfer is applied over the said layer.

4. A method according to Claims 1, 2 or 3 in which the layer of material is applied prior to the glass-toughening heat treatment cycle.

5. A method according to Claims 1, 2, 3 or 4 in which the layer of material comprises a coating of ceramic or vitreous material.

6. A method according to Claims 1, 2, 3, 4 or 5 in which the covering is applied by painting, spraying or rolling.

7. A method according to Claims 1, 2, 3, 4, 5 or 6, in which the design is formed by transfers which are applied to the glass panel with their edges overlapping one another, and including the step of cutting through the transfers in the region of the overlap along a line which follows the edge of a feature of the design, and removing the surplus portions of the transfers.

8. A method according to any of the preceding claims in which the layer of material is a layer of coloured material.

9. A method according to claim 8 in which the layer of material is of substantially uniform colour.

10. A method for producing a decorated glass panel comprising applying a design to one side of the glass panel as a plurality of water-slide transfers, the transfers comprising the design in vitreous enamels, the transfers being applied to the panel with their edges overlapping one another, and including the step of cutting through the transfers in the region of the overlap along a line, and removing the surplus portions of the transfers.

11. A method according to claim 10 in which the cut line follows the edge of a feature of the design.

12. A method according to any of the preceding claims, in which the panel simulate a natural grained material.

13. A method according to claim 12 in which the design is a reproduction of the grained effect of the simulated natural material and the layer of material reproduces the background colour.

14. A method for producing a glass panel with a decorative finish which consists of a design of relatively fine detail and an overall background colour, including the steps of forming a transfer printed with the design of fine detail in vitreous enamels or ceramics, applying the design to one side of a glass panel, subjecting the glass panel with the applied design to a glass-toughening heat treatment cycle, and including the step of applying a layer of material of the background colour on the same side of the glass panel as the transfer so that the decorative effect is produced by the design and the coloured layer.

15. A method according to any of the preceding claims in which the transfer is a water-slide transfer.

16. A glass panel produced by the method of any of the preceding claims.