GB2092524A - Producing multi-colour markings - Google Patents

Abstract

A substrate 3, e.g. of paper, card or board, is provided with two differently-coloured layers, 1, 2 one of the coating layers containing a pigment whose colouring properties may be substantially removed by application of a liquid reagent, e.g. in area 4. The lower layer may be decolourised if the upper layer is permeable to the reagent. The material finds application in advertising displays, for artistic purposes or as a toy; the reagent can be applied by brush, pen, stamp, spray, ink-jet, printers block or typewriter. <IMAGE>

Description

SPECIFICATION Improvements in or relating to display material This invention relates to display materials such as may be used for advertising or other artistic purposes. These include types of paper, card, or board but other materials having a surface which can receive a coating of pigment may also be used.

Hitherto coatings of different colours have been printed onto surfaces by sequential deposition of one dye onto another.

According to a first aspect of the present invention a display material comprising a surface, a coating of a first colour and a coating of a second colour overlying said coating of a first colour, one of said coatings incorporating a pigment the colouring properties of which may be removed or substantially diminished by application of a liquid reagent.

The term pigment as used herein is intended to include any dyeing or colouring agent which may be used in accordance with this invention.

Either of the coatings may be decolourisable. In embodiments of the invention in which an indelible layer overlies the decolourisible layer, the liquid reagent may permeate the indelible layer and react with the decolourisible layer.

Either of said first or second colours may be white.

According to a second aspect of the present invention an apparatus comprises a display material as hereinbefore described and a means of selectively applying a solution of decolourising agent to selected regions of said coating.

The aforementioned means may comprise a brush, fibre tipped pen, ballpoint pen, any other pen, a printer's block, a rubber stamp, an aerosol or any other type of spraying device, a typewriter or an inkjet printer.

The display material preferably comprises paper, card or board a surface of which has been indelibly covered, for example, by printing, with a first coloured pigment. The coating of the second colour overlies and obliterates said first colour. For example if the first colour is yellow and the second colour is blue, the surface will initially appear to be blue. Writing on the surface with a pen containing the decolourising agent will cause the blue colour in the regions written upon to be discharged revealing the yellow background. This has the visual effect of writing in yellow on a blue background.

A single pen or other means of applying the decolourising agent may, with the use of appropriately coated surfaces, be used to provide the visual effect of writing in a variety of colours on a variety of different backgrounds.

The decolourising agent may be an oxidising or reducing agent, an acid or base or any other convenient substance and may be applied in liquid form or in solution in water or in an organic solvent.

Apparatus in accordance with this invention may find application as a toy.

For example a child's colouring toy may incorporate a book containing single-coloured pictures which may be "coloured-in" using one or more fibre-tipped pens containing the liquid reagent. Alternatively a stamping set may comprise a pad impregnated with the liquid reagent and a stamp or selection of stamp, which may be used to stamp images onto a surface in accordance with the invention.

The invention is further described by way of an example with reference to Figs. 1 to 6 of the accompanying drawings, of which: Figure 1 shows a cross section of a display material in accordance with the invention; Figure 2 shows the application of liquid reagent with a felt-tipped pen to the material shown in Fig. 1; Figure 3 shows the result of treatment of the material shown in Fig. 2; and Figures 4 to 6 show corresponding stages of use of another display material in accordance with the invention.

The same reference numerals are used to denote like parts in each of the drawings.

The display material shown in Fig. 1 comprises a sheet of paper 3, overprinted with a layer of an indelible ink 2. A layer of decolourisible ink 1 is printed over the indelible layer 2.

Fig. 2 shows application of a liquid reagent 6 onto the decolourisible layer 1 by means of a felt-tipped pen 5.

Fig. 3 shows how a region 4 of the decolourisible layer 1 to which the liquid reagent 6 has been applied is bleached by reaction with the liquid reagent. This exposes the colour of the underlying indelible layer.

Figs. 4 to 6 show a display material in which the decolourisible layer underlies the indelible layer. Use of this material is analogous to that shown in Figs. 1 to 3 except that the background colour of the product is decolourised upon application of the liquid reagent which permeates through the surface layer leaving the colour of the surface layer uneffected.

A suitable decolourisible pigment is that marketed under the name REINOL by Reinol SpA.

An appropriate liquid reagent may comprise an aqueous solution of a reducing agent such as an alkaline solution of a sulphite together with a complexing agent such as potassium sodium carbonate and a substance which forms a protective coating to prevent atmospheric oxidation of the reduced pigment such as polyethylene glycol or sodium silicate.

Alternative pigments which may be deco lourised by acids or alkalies such as Indigosol O may be employed, the liquid reagent for use with the latter being diluted hydrochloric acid.

The indelible coating may comprise any convenient pigment which is not decolourised by the liquid reagent, for example Auramine 0, induline dyes such as Induline Blue 6B or Monastral Fast Blue BS.

Decolourisible pigments in accordance with the invention may be applied in conventional manner from aqueous solution comprising the pigment, a glycol, a surface active agent, antifoaming agent and an anti-frothing agent.

Claims (10)

1. Apparatus comprising a display material comprising a surface, a coating of a first colour and a coating of a second colour overlying said coating of a first colour, one of said coatings incorporating a pigment the colouring properties of which may be removed or substantially diminished by application of a liquid reagent.

2. Apparatus as claimed in Claim 1, wherein said coating of a second colour incorporates the said pigment.

3. Apparatus as claimed in Claim 1, wherein said coating of a first colour incorporates the said pigment.

4. Apparatus as claimed in any preceding claim wherein either of said colours is white.

5. Apparatus as claimed in any preceding claim and incorporating means of selectively applying a solution of said reagent to a selected region of said coatings.

6. Apparatus as claimed in Claim 5, wherein said means is selected from a brush, a fibre tipped pen, a ballpoint pen, any other pen, a printing block, a rubber stamp, an aerosol or other spraying device, a typewriter or an inkjet printer.

7. Apparatus as claimed in any preceding claim wherein said surface comprises paper, card or board.

8. Apparatus as claimed in any preceding claim, wherein said reagent comprises either an oxidising agent or a reducing agent.

9. Apparatus as claimed in any one of claims 1 to 5 wherein said reagent comprises either an acid or a base.

10. Apparatus substantially as hereinbefore described with reference to and as illustrated in Figs. 1 to 3 or Figs. 2 to 6 of the accompanying drawings.