PRODUCTION OF COLOURED LEGENDS

Abstract: Coloured legends can be produced using a combination of dry transfer lettering which is available in many styles but few colours, and blocking foil available in a wide variety of colours. The legend is first built up in e.g. black or white and the blocking foil laid thereon. The substrate on which the legend is built up is such that on subjecting the blocking foil to heat and pressure colour transfers to the legend. If the foil is appropriately formulated, the coloured legend may then be heat transferred to the back of a transparent or translucent sign sheet to form a sign.

Description: Production of Coloured Legends • This invention relates to the production of coloured legends. In many areas of display and graphic work, it is desired to produce wording in colour, i.e. in colours other than black and white. The most versatile system is of course to hand draw and colour the letters, but this is skilled work and time consuming. In recent years, very wide use has been made of so-called ' dry -cransfer lettering sheets for building up legends and these are produced in a very wide variety of typefaces and sizes. However, such sheets are normally only available as stock items in • black, white and (for the more popular typefaces and sizes) a few other colours, such as red, yellow, green, blue, silver and gold. If other colours are required, one approach is to make up the desired legend in black, and then convert it photographically into the desired colour. This is clearly both time consuming and expensive. An alternative approach to producing coloured legends is to use a blocking foil. Such foils are produced, in a very wide variety of colours and legends- may be produced from them by assembling the legend in a relief type, usually hot brass type, and pressing that type onto the desired receptor such as a piece of card or art board with interposition of the blocking foil. Under the action of the heat and pressure, part of the ■ • coating of the blocking foil transfers to the card or art board and when the pressure is released and the foil peeled away the letters are reproduced in the blocking foil colour on the card or art board. Such systems require a hot press as well as investment in appropriate relief type. The flexibility of the system i__ accordingly small. OMPI IPO International Patent Application No. PCT/GB79/00 3 (Publication No. ¥080/00462) discloses a system for decorating garments and the like using two successive transfer steps. In a first step, a transfer having the form of the intended decoration is applied to the garment surface under heat and pressure and in a second step, a foil, having a metallised and/or pjg ented coating, is applied to the already applied image, under heat and pressure, and the foil then peeled away to leave the desired image with the desired finish adheren-fc to the garment. Page 5 of the published specification indicates that other substrates may be decorated in this way. This system required the use of heat transfers and their attendant apparatus and is unsuitable for many graphic arts applications, particularly for manufacturing * art work, e.g. for advertisements, product packaging, mock-ups, and the like. Particularly where it is desired to build up an image from the trans er of a set of separate images sequentially, it is impractical to do this using a heat transfer method, owing to the difficulties of aligning each image with the previous ones.. We have now found that if care is taken, it is possible to overcome these disadvantages by using a two-stage process of which the first is a dry transfer process using pressure only and the second, a heat and pressure blocking foil process. By combining these two systems, a system is produced which has all the flexibility in terms of typeface and "t pe size associated with dry transfer lettering, all the flexibility of colour associated with blocking foils, but which is nevertheless easy and straightforward to put into practice. According to the present invention there is provided a method of making a coloured legend which comprises transferring on to a desired receptor a plurality of dry transfer indicia to make up the / -^J_Ϊ1_A desired legend, assembling over the so transferred indicia a blocking foil, and subjecting the assembly of receptor, indicia and blocking foil to heat and pressure, the conditions of time, temperature and pressure and the respective formulations of the transferable coating on the blocking foil and of the dry transfer indicia being such that after such heat and pressure treatment the coloured coating of the blocking foil adheres to the transferred indicia rather than to the blocking foil base when the blocking foil is pulled away and wherein ' the formulation of the blocking foil coating and the surface of the receptor sheet are such that under those same conditions of time,temperature and pressure the coating does not release from the blocking foil. In this way, a coloured legend may be easily and rapidly obtained in any colour available as a blocking foil. Not all commercially available foils work with all commercially available dry transfer lettering types and on all receptor surfaces, but it is simple to determine experimentally which types work and under what optimum conditions. The subjection of the assembly of foil, and indicia and receptor to heat and pressure may be carried out using a heated press of known type, either with flat plates or heated rollers, .or by using a hand-held heated roller which is rolled over the assembly. The attainment of such a coloured legend may be all that the graphic artist or the like wishes, but it is possible so to formulate the blocking foil, and this constitutes a particularly preferred feature of the present invention, that the coloured legend formed on the receptor surface may subsequently be transferred, under the action of heat and pressure, to the rear surface of a transparent or translucent sign sheet through which it may be viewed and which serves as a OMPI __ protection for that legend. Accordingly, in this aspect, the present invention constitutes a further development of the sign making system disclosed in British Patent Specification 2,005,596. The following Example will .serve to illustrate the invention: EXAMPLE It was desired to make up a sign employing red lettering. First, a sheet of white lettering dry transfer material (Sign-Type ex SI Sign Systems Inc.) was taken and the desired legend built up by transferring successive letters on to a polyethylene terephthalate foil (Melinex ex Du Pont) 0.1 mm thick. A sheet of red blocking foil (ex Kensol type DR35) • was laid, coated side down, on the foil bearing the white lettering,and both foils then passed through a heated nip between two silicone rubber covered rollers at a speed of 1 m/min. and roller surface temperature of 120°C. The rubber durometer hardness was 70 and the compression across the nip was 0.75 mm (i.e. the roller centres were 0.75 mm closer than with the rubber coverings touching but uncompressed). The foil backing was peeled away and it was found that the red coating thereon (based on a polyisobutyl methacrylate/dye/pigment composition) had transferred only to the letters. A sheet of 3 mm thick matt finish polymethyl methacrylate sheet (Plexiglas ex Rohm & Haas) was then laid on the red letters and the assembly again passed through the nip under the same conditions. The polyethylene terephthalate backing was then peeled off to leave a legend visible through (and protected by) the methacrylate sheet. A white spray paint coating was applied-over the letters to give a contrasting background.

Claims: C L A I M S . A method of making a coloured legend which comprises the following steps: transferring on to a desired receptor a plurality of dry transfer indicia to make .up. the desired legend, assembling over the so transferred indicia a blocking foil, subjecting the assembly of receptor, indicia and . blocking foil to heat and pressure, and removing the blocking foil backing from the assembly, . the conditions of time, temperature and pressure and the respective formulations of the transferable coating on the blocking foil and of the drr transfer indicia being such that after applying heat and pressure the coloured coating of the blocking foil adheres to the transferred indicia rather than to the blocking foil backing when the blocking foil backing is pulled away, and wherein the formulation of the blocking foil coating and the surface of the receptor sheet are such that under those same conditions of time, temperature and pressure the coating does not release from the blocking foil backing and adhere to the receptor sheet. 2. A method of making a sign which comprises making a coloured legend according to the method of claim 1 on a receptor from which the indicia may be cleanly removed, placing a transparent or translucent sign sheet over the coloured legend, subjecting the assembly of receptor and sign sheet to heat and pressure, and removing the receptor from the sign sheet, the conditions of time, temperature and pressure, and the materials of the sign sheet, blocking foil coating, indicia, and receptor being such that on the removal of OMPI the receptor the coloured legend remains adherent to the sign sheet.

Inventors: DOWZALL EDWARD MARTIN, DOWZALL, EDWARD, MARTIN
Applicants: LETRASET INTERNATIONAL LTD, LETRASET LIMITED
Application year: 1981
Main classification: B41M3
IPC codes: B41M3, B44C1, D06Q1