GB2179889A - Designs on glass - Google Patents

Abstract

A water-slide transfer for applying designs to glass articles comprises a substrate of gummed paper 12 on which the design 14 is printed by silk-screen printing using a printing medium of glass frits coloured with vegetable dyes. A layer 15 of stoving enamel is printed over the whole design and hardened by exposure to ultra-violet light. A covercoat 16 of acrylic resin is then overprinted on the varnished design and a surrounding area of the gummed paper. To apply the design, the transfer is soaked in a solution of cellulose wallpaper paste until the design is loose and then the design is applied to the glass which has been previously warmed to a few degrees above room temperature. The acrylic covercoat is peeled away to expose the design with its varnish layer which are left on the glass. <IMAGE>

Description

SPECIFICATION Designs on glass The present invention relates to a method and arrangement for producing a coloured design on a glass article, especially glass panels, for example window panes.

Various techniques have been hitherto used for producing coloured designs on glass. One technique is to prepare the design on a transparent base as a water-slide transfer and then to apply the transfer to the glass article.

Such transfers are however easily damaged, by scratching. Sometimes a coat of varnish is applied over the design after it has been applied to the glass to afford some protection.

However such a coating will not withstand scratching with a hard object such as a coin.

Another technique involves applying the design in the form of vitreous enamels and fusing it to the glass but this technique involves the article being heated to a temperature of about 600"C or higher and therefore can only be performed in special ovens.

An object of the present invention is to provide a system for producing coloured designs on glass which are reasonably durable and yet can be applied without specialist equipment.

According to the present invention in a first aspect there is provided a transfer for applying a design to glass, comprising a substrate, a design applied to the substrate and a layer of stoving enamel varnish applied over the design.

Preferably the design is multi-coloured and applied to the substrate by a printing technique. The printing medium should be resistant to prolonged exposure to light and we have found that glass frit coloured with vegetable dyes has satisfactory light fastness, and enables transparent colours to be produced.

The transfer may be a water-slide transfer and in this case the substrate may comprise a sheet of gummed paper.

The varnish may be hardened by exposure to ultra-violet light and a covercoat of, for example, acrylic resin may be applied over the varnish to assist in transferring the design.

In the case of a water-slide transfer the design is applied by first loosening the transfer from the substrate by soaking the transfer in water and then lifting the transfer from the substrate and placing it on the glass.

We have found that improved results can be obtained if a quantity of adhesive, for example, wallpaper paste, is added to the water in which the transfer is soaked. When a transfer is soaked in plain water some of the gum on the gummed paper dissolves in the water, some remains on the paper and some attaches itself to the back of the design. This can produce an uneven layer of gum on the back of the transfer design which in cases where the design is of light transmitting colours spoils the appearance of the finished design because the variations in thickness of residual gum cause variations in the amount of light transmitted by different parts of the gum layer. Soaking in a solution of adhesive causes a more uniform layer of adhesive to be deposited on the back of the design which not only improves the adhesion to the glass but also improves the appearance of the finished article.

Thus, according to the present invention in a second aspect a method of applying a design to a glass article includes soaking a water-slide transfer in a solution of a watersoluble adhesive, removing the transfer from its substrate and placing the transfer on the surface of the glass article.

We have also found that it is beneficial to heat the glass to a few degrees above room temnperature, say, to around 80"F(25"C), prior to the application of the transfer.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawing in which the sole figure is a cross-section through a transfer.

A water-slide transfer 11 is prepared by printing a design on gummed paper using a heat resistant light-transmitting printing medium. The printing medium may be prepared as follows.

A clear glass frit is produced by melting down glass, cooling it rapidly, and then crushing and grinding the resulting product into a fine powder. The glass frit thus produced is then dyed to create the desired colours using commercially-available vegetable dyes that have good colour fastness on exposure to light.

The gummed paper 12 has a coating layer 13 of gum arabic. The design 14 is printed on the gummed side of the paper 12 using a silkscreen printing technique building up the design in several colours. The design may, for example, be a reproduction of a stained-glass window.

When the design is completed and has been allowed to dry, it is overprinted with a layer 15 of stoving enamel varnish which covers the whole of the design and a surrounding margin on the gummed paper substrate.

The stoving enamel layer 15 is exposed to ultra-violet light to harden and then overprinted with a layer 16 of acrylic resin to form a strippable covercoat. The covercoat covers the varnished area and a surrounding margin of the gummed paper. It has an extension 17 to form a tab to assist in picking up the covercoat, and thus the transfer, from the surface of the gummed paper.

When it is desired to apply the design to a glass article, for example, a window pane, the transfer is soaked in a trough of water at room temperature to which cellulose wallpaper paste has been added at the rate of one teas poon per pint of water.

The surface to which the transfer is to be applied is cleaned and degreased and then warmed gently by heating with a portable electric hair dryer. The transfer is lited from the gummed paper substrate by means of the acrylic resin covercoat, placed on the window pane and slid into position. When correctly placed the transfer is pressed down with a squeegee to remove all air pockets and creases. Finally the transfer is wiped with a damp sponge to remove excess moisture and allowed to dry. The acrylic covercoat is then carefully peeled from the transfer, leaving the design with its stoving enamel varnish coating on the glass.

We have found using this technique that a decorated glass panel is produced which is heat resistant and does not discolour at temperatures up to 160"C, is resistant to stain and chemical attack, is abrasion and scratch resistant, and the design has good adhesion to the glass panel. Decoration can be applied to glass windows and doors in situ and no special equipment is reqired to apply the transfer.

Claims (15)

1. A transfer for applying a design to glass comprising a substrate, a design applied to the substrate and a layer of stoving enamel varnish applied over the design.

2. A transfer according to claim 1 in which the design is applied to the substrate by printing.

3. A transfer according to claim 1 or 2 in which the design is of coloured glass frits.

4. A transfer according to claim 3 in which the glass frits are coloured with vegetable dye.

5. A transfer according to any of claims 1 to 4 in which the substrate is a sheet of gummed paper.

6. A transfer according to any of claims 1 to 5 in which the varnish is hardened by exposure to ultra-violet light.

7. A transfer according to any of claims 1 to 6 in which the varnish is covered by a covercoat.

8. A transfer according to claim 7 in which the covercoat is of acrylic resin.

9. A method of applying a design to glass using a transfer according to any of the preceding claims including the step of soaking the transfer in liquid, removing the design with the varnish layer from the substrate and applying the design with varnish layer to the glass.

10. A method according to claim 9 in which the liquid comprises an adhesive solution.

11. A method according to claim 10 in which the adhesive solution comprises wallpaper waste in water.

12. A method of applying a design to a glass article including the steps of soaking a water-slide transfer in a solution of a watersoluble adhesive, removing the transfer from its substrate and placing the transfer on the surface of the glass article.

13. A method according to any of claims 9 to 12 including the step of heating the glass prior to application of the transfer.

14. A transfer substantially as hereinbefore described with reference to the accompanying drawings.

15. A method of applying a design to glass substantially as hereinbefore described with reference to the accompanying drawings.