GB2249051A - Production of artwork - Google Patents

Abstract

A legend is applied to artwork after preliminary assembly of the legend from individual dry transfer indicia symbols and the like on an intermediate carrier from which the indicia may be cleanly peeled. Clean peel is effected by adhering to the indicia surfaces remote from the intermediate carrier an adhesive web. In accordance with the invention, the adhesive web bears a heat activated adhesive coating. By choice of brittle thermoplastic resins for the heat activated adhesive, the adhesive web may be used either to peel the indicia away from the intermediate carrier and subsequently transfer them to the desired final receptor surface, or to put a layer of heat activated adhesive selectively on the surfaces of the indicia enabling those surfaces to be reliably coloured using a hot blocking foil.

Description

PRODUCTION OF ARTWORK This invention relates to the production of artwork.

European Patent Publication 0058066 describes a two stage system for producing artwork in which a desired legend is first assembled using a dry transfer material on an intermediate carrier and is then released as a whole from that intermediate carrier while being supported by an adhesive web which is then manipulated to position the legend where desired, whereafter the individual indicia making up the legend can be applied to a desired final substrate. This has the major advantage of separating the assembly of the legend, for example a word or words, from individual letters from the positioning of the legend where desired. European Patent Publication 0130837 discloses the use of such a system with the additional step, while the legend is on the intermediate carrier, of colouring the indicia of the legend, e.g. by spraying colour on to the indicia, or the use of a hot blocking foil.

The system described in Specification 0058066 has been commercialised (under the trade mark LETRASET WORD POSITIONING SYSTEM) and is widely used. However, the need to use special absorbent paper as the intermediate carrier and liquid to impregnate through that paper to release the legend therefrom, is inconvenient and satisfactory use takes time and skill.

In accordance with the present invention, the indicia to make up the legend are laid down on an intermediate carrier having a surface from which they may be peeled cleanly and are removed from that surface by the application, to the surfaces of the indicia remote from the surface of the intermediate carrier to which they are adhered, of a heat-activated adhesive web.

The heat activated adhesive web may be one which consists of a flexible carrier bearing an applied layer of a heat activated adhesive of known type or it may be a flexible material which may be uncoated or bear a coating not normally thought of as adhesive but in either case which will interact under the action of heat and pressure to promote sufficient adhesion between the surfaces of the indicia remote from the surface of the intermediate carrier and the web that when the web is pulled away, that adhesion overwhelms the bond between the intermediate carrier and the indicia.

This approach is fairly dependent upon the respective nature of the heat activated adhesive web and the material of which the indicia are made, and not all combinations work equally well. We have found, however, that standard commercially available Instant Lettering dry transfer materials (ex Esselte Letraset Limited) can be removed from the intermediate carrier using as adhesive web either plain uncoated polyethylene terephthalate films or, with slightly greater ease, polyethylene terephthalate films coated with a polystyrene resin or an acrylic resin.

In one particular way of putting the invention into practice, the web causes a coating of a heat activated adhesive of a type which has a relatively high adhesive power to surfaces with which it is in contact only while it is hot or for a relatively short time thereafter. A variety of heat activated materials with adhesive properties of this type are known. Preferred for use in the present invention are relatively hard transparent or translucent thermoplastic resins. Such materials may be brittle and relatively unadhesive when at room temperature, but become vigorously tacky when heated above a certain temperature, for example heated above 100 CC, preferably above 130 CC.

The resin type may vary widely. Polyvinyl chloride, polyvinyl acetate and polyamide resins may all be used though acrylic resins are preferred. One disadvantage of acrylic resins is that they tend when coated to form coatings of high cohesive strength which do not shear easily when the indicia making up the legend are applied to the final receptor surface and the adhesive web is pulled away. Shearing may be promoted by including in the coating a proportion of a higher melting point resin.

If a heat activated adhesive of this type is used immediately after heating, the adhesive web may be pulled away from the intermediate carrier on which the indicia were assembled to form the legend, carrying the indicia on its underside. If, however, the assembly is allowed to cool before pulling the adhesive web away, on peeling away the indicia remain adhered to the intermediate carrier.

This feature can be of use if the adhesive on the adhesive web, in such circumstances, separates from the web and remains adhered to the surface of the indicia. This may be achieved by forming the adhesive web of a flexible substrate on to which a release coating has been applied such that, unless hot, the adhesive does not stick very well to the carrier web of the adhesive web. The release coating may be, for example, a wax coating such as of microcrystalline wax, or a modified rosin ester coating (e.g. Pentalyn 261 or 830, ex Hercules Inc.) or a styrene-maleic resin (e.g. Suprapal AP20, ex BASF) or a polyamide resin (e.g. Krumbhaar P-1084, ex Lawter Chemicals), in each case applied by coating an emulsion or solution using a wire wound bar, wire diameter 75 or 125 pm.

The release coating enables the heat activated adhesive to remain on the surface of the indicia if the web carrying the heat activated adhesive is peeled away in the cold, i.e. after the adhesive has been heat activated and then allowed to cool.

This can be useful insofar as it allows colouring of the legend to take place easily by the use of an applied hot blocking foil. The hot blocking foil may be applied either while the assembled legend is on the original substrate (after a layer of adhesive from the adhesive web has been deposited on it) or it may be applied following transfer of the legend to the final artwork.

As in the prior art, the adhesive web substrate is preferably a thin plastics film of greater extensibility under load than the combination of the adhesive film and the material of the dry transfer letters and other indicia themselves, so that the transfer to the final artwork is achieved easily using the stress release mechanism described in British Patent Specification 959670.

Preferred substrates are polyethylene terephthalate films, e.g. 25 or 50 iim thick (e.g. Hostaphan Series 2000 ex Hoechst Celanese Corp., Melinex HS ex ICI).

In cases where the letters or other indicia, adhered to the final artwork, have a layer of adhesive from the adhesive web on their exposed faces, the final appearance of the transferred legend may be varied by varying the surface finish of the plastics film from which the adhesive layer has stripped or, e.g. by a subsequent heat and pressure treatment of the adhesive layer in contact with a release surface of appropriate texture.

If desired, more than one colour layer may be applied to the legend either while it is on the intermediate carrier on which it is originally built up or following its transfer to the artwork. For example, satisfactory results may be obtained by applying first a white coating to standard black dry transfer lettering or symbols followed by the further application of a further colour over the white coating.

Colouring may be effected by a variety of methods while the legend is on the intermediate carrier on which it is originally assembled, for example by overpainting with a brush or spray, conditions desirably being such that the brushed or sprayed on colour will be pulled up with the indicia forming the legend but outside of the indicia will remain adherent to the intermediate carrier.

The intermediate carrier may be any convenient material having a surface from which the legend may be cleanly peeled. Parchment paper treated with a release coating (though not a very high release coating) works admirably.

Wax/Quilon release coats are satisfactory. Certain plain papers with very smooth surfaces may even be used without any surface treatment. Very smooth surfaced papers are commercially available, in particular designed for use in laser printers. An example of a commercially available paper which works well is Hammermill Laser Plus (ex Hammermill Paper Group). Untreated smooth vegetable parchments (e.g. James River Corporation paper reference 01627, 73gsm base weight) may be used. Yet a further paper which can be used is resin coated bond paper using a styrene butadiene rubber resin (e.g. Pliolite S-5B, ex Goodyear Chemical deposited from a hydrocarbon solvent).

It is particularly useful to use a very smooth surface but otherwise untreated plain paper if, while the indicia are on the intermediate carrier, they are coloured by a spray colouring method, for example air brushing, since the colouring then tends to adhere firmly to the exposed paper surfaces between the applied indicia and does not tend to be picked up by the subsequent application of the heat activated adhesive web.

The application of heat to activate the adhesive is conveniently accomplished using an appropriate hand-held heating device, for example a heated roller or a heated pad. Both are available in commerce, for example under the designations Letracopy C40 for a hand-held heated roller and TAG for a hand applied heated smoothing pad, both available from Esselte Letraset Limited.

The following examples will serve to illustrate the invention: Example 1 A legend was assembled on Quilon coated parchment paper from standard commercially available dry transfer material (Instant Lettering ex Esselte Letraset Limited).

Polyethylene terephthalate film (50 microns thick, Melinex ex ICI) was coated with a wax release composition. The coating was applied as a very thin layer by diluting a commercial wax release emulsion (Hoechst Wax 6023 ex Hoechst Chemicals, an oxidised polyolefin wax dispersed in a water/alkali/surfactant mix) which was diluted with water to a 5 percent solids content concentration prior to application using a number 3 Meyer bar (wire diameter 75 pom). Following the application of the coating composition, and drying down at 50"C for 1 minute, sheets of the polyethylene terephthalate release coated film were coated with a coating of brittle resin.The resin used was a modified phenolic resin (Arochem 455 ex Reichold Chemical Inc Melting Point 130-140"C). A 25 percent by weight solution of this resin in industrial methylated spirits was coated on the release coated sheets using a number 10 wire wound bar (wire diameter 250 Sum) and the coating dried down at a temperature of 70"C for 1 minute.

A piece of this resin coated polyethylene terephthalate substrate was then laid, resin side down, in contact with the assembled legend and a heated pad heated to a temperature of 1500C was passed over the assembly following which the polyethylene terephthalate sheet was immediately peeled away from the Quilon coated parchment paper. The indicia complete with the pressure sensitive adhesive making up the legend stayed on the underside of the polyethylene terephthalate sheet.

The polyethylene terephthalate sheet is transparent and accordingly can be positioned to place the legend precisely where desired over a piece of artwork, e.g. on a layout for an advertisement. Once so positioned, the legend may be released from the polyethylene terephthalate sheet by burnishing over the back of that sheet with a burnisher. The indicia forming the legend release together with the phenolic resin coating from the polyethylene terephthalate film and adhere, by virtue of the adhesive originally on the indicia when they were part of the dry transfer sheet, to the artwork in the desired position. No resin transfers from the polyethylene terephthalate sheet outside the areas of the indicia. The polyethylene terephthalate sheet was then discarded.

The so applied legend could be coloured by the application of a hot blocking foil thereto, e.g. a foil strip sold under the trade mark Omnicrom by Esselte Letraset Limited, applied using the heated pad wiped over the back of the hot blocking foil while the latter is laid over the legend.

Example 2 Example 1 was repeated but using instead of the phenolic resin and release coated polyethylene terephthalate sheet a commercially available polybutyl methacrylate resin coated polyethylene terephthalate base film (BEA 000-2 ex Crown Roll Leaf).

Similar satisfactory results were obtained.

Example 3 A legend was built up on smooth surface paper (Hammermill Laser Plus, ex Hammermill Paper Group) using commercially available dry transfer lettering (Instant Lettering, ex Esselte Letraset Limited). As heat activated adhesive web, there was used a coated 50 ym thick polyester film.

The coating was of a polystyrene resin (Styron 685D, ex Dow Chemical Corp) having a softening point of 108OC.

This resin could be coated from a solution in aromatic hydrocarbon solvent using a concentration of 8 to 20t by weight, preferably around 15% by weight, and using a wirewound bar to effect coating with a wire diameter of 75 or 125 rm.

Following drying down of the polystyrene resin coating, the polyethylene terephthalate film was laid, coating side down, on top of the legend and the assembly passed through a heated nip whereafter the polyethylene terephthalate sheet and paper sheet could be peeled apart to leave the legend attached to the underside of the polyethylene terephthalate sheet.

This sheet could then be used in the same fashion as a sheet of standard dry transfer lettering is used to transfer the entire legend to the final desired receptor surface. The indicia forming the legend transferred perfectly to the final receptor surface leaving the polystyrene resin coating apparently unaffected and extending continuously over the surface of the polyethylene terephthalate film.

Example 4 A heat activatable adhesive web was made by coating a 50 thick polyethylene terephthalate sheet (Hostaphan Series 2000, ex Hoechst Celanese Corp) first with a release coat and then with a resin coat.

The release coat was a commercially available wax emulsion (Hoechst Wax 6023 as in Example 1) but diluted to a 10% solids concentration before application using a 75 jim diameter wirewound bar. After drying down the wax emulsion release coat, a mixed resin coating was applied.

The coating composition consisted of (parts by weight) acrylic resin (Acryloid B66, ex Rohm and Haas Co, softening point Tg 50"C) 1 part resin (Pentalyn 261, ex Hercules Inc, softening point 177to) propylene glycol monomethyl ether 10 parts This coating composition was applied using a 125 jim diameter wirewound drawdown bar.

The assembled legend could be removed cleanly from the wax coated paper with the assistance of a handheld heated roller (Letracopy C40, ex Esselte Letraset Limited).

Example 5 Example 4 was repeated but using as the coating composition a 15% by weight solution of the acrylic resin in xylene.

Similar satisfactory results were obtained.

Claims (8)

1. A method for producing artwork consisting of a legend on a desired final substrate in which, in a first stage, a desired legend is assembled using a dry transfer material on an intermediate carrier, the legend is then released as a whole from that intermediate carrier while being supported by an adhesive web, the adhesive web is then manipulated to position the legend where desired, and the individual indicia making up the legend are then applied to the final substrate, wherein the indicia to make up the legend are laid down on an intermediate carrier having a surface from which they may be peeled cleanly and are removed from that surface by the application, to the surfaces of the indicia remote from the surface of the intermediate carrier to which they are adhered, of a heat-activated adhesive web is a heat activated adhesive.

2. A method according to Claim 1, wherein the heat activated adhesive web comprises a carrier film carrying a layer of a heat activated adhesive of a type which has a relatively high adhesive power to surfaces with which it is in contact only while it is hot or for a relatively short time thereafter.

3. A method according to Claim 2, wherein the adhesive is a relatively hard transparent or translucent thermoplastic resin.

4. A method according to Claim 2 or 3 and including the additional steps of applying the web carrying the heat activated adhesive to the indicia while they are on the intermediate carrier on which they have been assembled to form the legend, or when they have been transferred to the final substrate, allowing the assembly of adhesive web and indicia to cool, peeling the adhesive web away to leave the indicia remaining adhered to the intermediate carrier or final substrate, and then colouring the legend by the use of an applied hot blocking foil.

5. A method according to any one of Claims 1 to 4, wherein a thin plastics film of greater extensibility under load than the combination of the adhesive film and the material of the dry transfer letters and other indicia.

6. A method according to any one of Claims 1 to 5, wherein the intermediate carrier is parchment paper treated with a release coating.

7. A method according to any one of Claims 1 to 6, wherein the application of heat to activate the adhesive is accomplished using a hand-held heated roller or a heated pad.

8. A method according to Claim 1 and substantially as hereinbefore described with reference to any one of the foregoing specific Examples.