US 3708320 A
Description (OCR text may contain errors)
Jan. 2, 1973 G. c. HURST ETAL 3,708,320
TRANSFERS Filed Oct. 2, 1969 s ,,,.4 H, ,2 51 \l i 13 k\(\\\ I FIG.|
INVENTORS GERALD COVINGTON HURST ALAN BELASCO United States Patent Office 3,708,320 Patented Jan. 2, 1973 3,708,320 TRANSFERS Gerald Covington Hurst, Coulsdon, and Alan Belasco,
Kenley, England, assignors to George M. Whiley Limited, South Ruislip, Middlesex, England Filed Oct. 2, 1969, Ser. No. 863,143 Claims priority, application Great Britain, Oct. 14, 1968, 48,648/ 68 Int. Cl. B41m 3/12; B44d 1/14 US. Cl. 1173.3 3 Claims ABSTRACT OF THE DISCLOSURE This invention relates to transfers which include a carrier sheet having disposed thereon a release layer, a lacquer layer, an ink or dye layer covering an area less than that of the carrier sheet and adapted to be protected by said lacquer layer, and a layer formed from a metal and superposed on the ink or dye layer.
This invention relates to transfers and more particularly, but not exclusively, to heatand/ or pressure-sensitive transfers.
Pre-printed designs, transferable from a carrier by the action of heat and pressure, incorporating only coloured areas, are known. Also known are hot stamping foils which include a lacquered metal or coloured layer which is transferable to a surface by the action of heat so as to reproduce the design of a metal die. These are also used with flat rubber dies to cover the raised part of a moulding. See Modern Plastics Encyclopedia 1968, pp. 1016- 1019.
Previously, when it has been desired to produce a design, part of which has a metallic appearance, it has been necessary to build up the design in a series of layers. The desired effect would thus be achieved by employing stamping foils of different types in several operations. Obviously, such a process is inefficient. In this connection, it should also be borne in mind that, in practice, it is difficult to apply metal in a vacuum chamber to only a limited part of a surface.
Consequently, it is an object of the present invention to provide a transfer capable of providing in one step a finish for, for example, a plastics, paper or wood surface, similar to the finish obtained by a succession of hot stampings with both coloured sheets and lacquered aluminium stamping foils.
According to one aspect of the present invention, there is provided a transfer which includes a carrier sheet having disposed thereon an ink or dye layer covering an area less than that of the carrier sheet, and a layer formed from a metal and superposed on the ink or dye layer, and an adhesive layer applied only to that part of the metal layer where it is intended that the design layer be transferred.
According to another aspect of the present invention, there is provided a method for producing a transfer according to the present invention, which method comprises applying an ink or dye to part, but not all, of one side of a carrier sheet, and forming by vapour deposition a layer of metal on the partially inkor dye-coated side of the carrier sheet, and applying an adhesive composition to the metal layer only in those parts where it is intended that the design be transferred.
Aluminium is a particularly suitable metal for the metal layer since a layer of it can be formed easily by known vapour coating techniques. Examples of other metals suitable for the metal layer include gold and antimony, although these are more expensive than aluminium. It will be appreciated of course that any metal which has a desired colour and which can be formed into the metal layer can be used.
In one embodiment of the invention, the transfer has, going from one side of the transfer to the other, a carrier sheet, a release layer, a lacquer, an ink or dye layer covering part of the lacquer layer, a metal layer and an adhesive layer. The production of this type of transfer will now be described.
Firstly, a thin carrier sheet, for example one formed from a polyethylene terephthalate film such as the commercially available Melinex or Mylar polyester film, is coated with a release layer. Melinex is a trademark of Imperial Chemical Industries, and Mylar is a trademark of El. du Pont de Nemours and Company. Other materials, e.g. nylon 6, may be used provided that they do not give rise to a high vapour pressure which would adversely affect the vacuum metallising operation hereinafter described. The release layer can comprise, for example, a heat softenable Wax-based composition similar to the release layers employed in the manufacture of stamping foils. It may be composed of a wax alone or of a wax and resin mixture. The composition is one which will provide a firm adhesion to the carrier sheet whilst cold and which will readily release the carrier sheet when warm or hot. Elastomeric substances such as natural rubber, may be included in the composition to improve adhesion during handling.
The release layer is next lacquered, either overall, for example by gravure or roller coating, or in part by the use of, for example, a silk screen or a partly etched gravure. The lacquer composition may be varied considerably provided that it is not affected adversely by the subsequent vacuum metallising process described hereinbelow, is not compatible with or affected adversely by the release layer, and adheres well to the metal, for example aluminium, layer. The following materials are examples of materials which have been used in preparing lacquers: nitrocellulose, methyl methacrylate and copolymers thereof, chlorinated rubbers, phenolic resins, non-drying alkyd resins, ureaformaldehyde resins, and epoxy resins.
After lacquering, that part of the design of the transfer which is to be coloured is printed in reverse, for example, by gravure, flexographic or silk screening. Examples of suitable ink for use in the printing include solutions of resins capable of binding pigments, and containing enough plasticising material to provide cohesion. In practice, the pigments Will have been dispersed in the resin by conventional means. It is convenient to incorporate a register mark into the design to facilitate the subsequent application of the adhesive coat as Well as the automatic application of the completed transfer.
Generally, at this stage it is necessary to thoroughly dry the material in order to remove moisture and solvent. The material is then subjected to a high vacuum and coated with the metal layer, for example aluminium.
Finally, adhesive is applied to the metal layer so that it covers each intended transfer area entirely but does not cover the space between the areas. The adhesive used must be capable of slight softening when heated and must form a firm bond with the material to which the design is to be applied. It will be appreciated that different adhesives are chosen for different surfaces, and it has been found advantageous to pigment the adhesive in order to provide a relatively thick layer without permitting flow from the areas to which it has been applied under the transfer conditions of heat and pressure. Any dispersed solid extender pigment or filler may replace the pigment without altering the characteristics of the system. Silk screen application has been found to be the most satisfactory method of obtaining good adhesive layers.
When the transfer is placed against the surface to which the design is to be applied and a heated press, for example a silicone rubber or laminated metal-rubber die, is pressed firmly against the transfer, the release layer melts and that part of the design which has been covered by the adhesive transfers to the article to be marked. The areas coated by lacquer alone give the appearance of a bright metal, for example gold or silver or a colour depending on the lacquer, and the remaining areas are the colour of the ink used, providing the lacquer is clear. If a very deeply coloured lacquer is used, it is generally applied to only part of the design, whereas a light or clear lacquer may be applied overall, in which case it provides overall resistance against abrasion to the design. Alternatively, the deeply coloured lacquer may be applied as an overall lacquer after the pigmented part of the design has been printed.
In another embodiment of the invention, the transfer is similar to that described in the first mentioned embodiment except that the lacquer layer and release layer can be combined so as to produce a single lacquer layer having the desired release properties with regard to the carrier sheet. Such a lacquer can be prepared from, for example, a solution of polymethyl methacrylate.
Mention has already been made of an adhesive which is capable of slight softening on heating but which forms a firm bond with the surface to which the design is to be applied. However, other types of adhesives can also be used-in the transfer of the invention, for example the type which is non-tacky in its ordinary state but becomes permanently adhesive when it is in the presence of a particular compound or upon heating. An example of the first type is one which becomes tacky when water is added to it and of the second type is one which is prepared from a copolymer of ethyl hexyl acrylate and a dispersed solid plasticiser such as cyclohexyl phthalate.
For a better understanding of the present invention, and to show how the same can be carried into effect, reference will now be made, by way of example, to the accompanying drawing, in which:
FIG. 1 is a cross-section through a transfer; and
FIG. 2 is a plan view of the design of the transfer of FIG. 1 applied to an object.
Referring firstly to FIG. 1, there is shown a transfer having a carrier sheet 1 adjacent a release layer 2 which in turn is adjacent a lacquer layer 3 on which has been deposited a design in ink 4. The ink 4 is covered by, and the spaces between the ink design 4 filled with, a metal layer 5 which has been formed by a metal vapour deposition method. On the metal layer is an adhesive layer 6 which covers only that part of the design which is to be transferred in use.
In FIG. 2 there is shown a design of the type which can be produced by applying the transfer of FIG. 1 to an article 7. The design consists of a coloured hollow rectangle 8 inside which is another rectangle 10, each rectangle being the colour of the ink 4, which can be different for the different rectangles. The area 9 is the colour of the metal layer 5 if the lacquer of the layer 3 is clear. Otherwise, the colour of the area 9 will depend on the combination of the colour of the lacquer 3 and that of the metal layer 5.
The invention will now be illustrated by the following examples.
EXAMPLE 1 about 1 gm. per square yard (of non-volatile matter) consisting of a 25% by weight solution of equal parts of Imperial Chemical Industries nitrocellulose DHX 8/13 and a methyl butyl methacrylate copolymer, dissolved in a mixture of equal parts by weight of methyl cyclohexanone and methyl ethyl ketone.
A design was then applied to the lacquer layer in black and blue inks.
The resulting product was dried and then vapour-coated with sufiicient aluminium to provide a bright continuous surface and cooled. To the aluminium was then applied an adhesive suitable for adhesion to paper, board or thermosetting plastics.
In the cases when the transfer was to be applied to polystyrene or cellulose acetate surfaces, a suitable adhesive was used.
The transfers were easy to prepare and the designs were found to be easily transferable.
EXAMPLE 2 A roll of biaxially oriented nylon 6 film, 25 microns thick, was coated on a conventional roller coating machine, with a release composition which consisted of 2 g. of a partly saponified ester wax (melting point -104 C.) and 0.05 g. of crepe rubber, dissolved in one litre of trichloroethylene. On drying, approximately 0.1 g. of release composition remained on each square metre of the nylon film. A clear lacquer having the following composition was then printed onto the carrier on a gravure machine so that there was about 1 g. of lacquer per square metre of dry material:
Chlorinated rubber g 100 Chlorinated parafiin wax g 50 Xylene c 300 The chlorinated rubber was that sold by Imperial Chemical Industries Limited under the registered trademark Alloprene R10 and the chlorinated paraifin was one obtained from the same supplier and known as Cerechlor 70.
A yellow and green design was applied in two stages, by silk screening, with inks which were ground dispersions of the following compositions:
The vinyl toluene used was one supplied by Messrs. Hubron Sales Limited, known as Pliolite VT.
The coated and printed nylon film was then well dried and a layer of aluminium was applied to it by vapour coating in the usual way.
Finally the whole area of the design, which it is intended to transfer, was coated, by silk screening, with a ground dispersion of pigment and resinous adhesive. The coating exceeded the area of the design by ,5 all round.
The carriers and transfers were reeled and cut longitudinally. Register marks were included in the design and the transfer was tested on automatic machinery.
It was found that the entire mark transferred well when pressed out on to polystyrene or methyl methacrylate surfaces, or on to coated fabrics and painted materials, using a heated silicon rubber pad, maintained at a surface temperature of about C. at a contact time of 2 seconds. The aluminium layer gave a bright silver appearance to the design where it ws not covered by the yellow or green ink portions. The design was surrounded by ,1 inch of bright aluminium where the adhesive overlapped the coloured ink. In a modification in which the adhesive coat was applied to the whole sheet, and not just to the design area, a similar result was obtained but it was necessary to shape the heatable rubber pad carefully (so as to restrict the area of transfer) and to ensure that the transfer design was registered very accurately with the article to be marked and the shaped rubber die.
EXAMPLE 3 A 100 gauge polyester carrier sheet, originally in roll form, was coated with a release layer as described in Example 1, then lacquered with a solution having the following composition:
G. Nitrocellulose DHX 3/5 (70%) 100 100% non-drying oil modified alkyd resin 50 Cyclohexanone 200 Isopropanol 50 Orange dyestuff The figures 3/5 indicate the time range in seconds for a stainless steel ball of cm. diameter to fall 50 cm. through a solution at 20 C. formed by dissolving 40 g. of the dry nitrocellulose in 100 ml. of 95% acetone (5% water).
The alkyd resin was one supplied by Imperial Chemical Industries Limited, known as Paralac 685.
A design in inks of several different colours formulated similarly to those described in Example 2 was applied in the same way. The resulting material, when well dried, was metallised with aluminum and an adhesive coat similar to that described in Example 2 printed on to the area of the design. This gave a transfer of much the same quality as the earlier examples, with the part of the aluminium not covered by ink, appearing as a pale gold, bright layer.
EXAMPLE 4 The lacquer and release coat described in Example 2 were applied to a polyester carrier sheet of 100 gauge. Then a design prepared from the same inks as described in Example 2 was applied to the lacquer layer. After drying, this was coated, by the usual vapour metallising technique, with gold from 23 carat gold wire to the extent of about 0.07 g. per square metre. After application of the adhesive coat, and upon transference, a bright and attractive transfer was obtained which had the additional advantage of great resistance to corrosion.
What is claimed is:
1. A transfer of the type consisting of a carrier sheet having a coating of release material on one surface thereof, a lacquer layer disposed on said release coating, an inkor dye design only partially covering one side of the lacquer layer and adapted to be protected by said lacquer layer, a layer formed from a metal deposited under vacuum and covering all of said design and covering all areas of said lacquer layer other than the areas of said lacquer layer having said design thereon, and an adhesive layer applied to only part of the metal layer, namely to that part where it is intended that the design be transferred.
2. A transfer of the type consisting of a polyester carrier sheet, a release layer formed of a heat softenable wax disposed on one side of the carrier sheet, a protective lacquer layer formed of nitrocellulose, a polymer of methacrylate, a copolymer of methacrylate, a chlorinated rubber, a phenolic resin, a non-drying alkyd resin, a ureaformaldehyde resin, or an epoxy resin disposed on the release layer on the side of said release layer remote from the carrier sheet, an ink or dye design disposed on the lacquer layer on the side of the lacquer layer remote from the carrier sheet, said design having an area less than that of the lacquer layer and only partially covering the area of said lacquer layer, a metal layer formed from aluminum, gold or antimony deposited under vacuum and covering all of the design and covering all areas of said lacquer layer other than the areas of said lacquer layer having said design thereon, and an adhesive layer formed of a heat softenable material disposed on the metal layer on the side of the metal layer remote from the carrier sheet and on only part of the metal layer, namely on that part where it is intended that the design be transferred.
3. A transfer of the type consisting of a polyester carrier sheet, a combined protective lacquer-release layer formed of polymethylmethacrylate disposed on the carrier sheet on one side thereof, an ink or dye design disposed on the lacquer-release layer on the side of the lacquer-release layer remote from the carrier sheet, said design only partially covering the areas of said lacquer-release layer, a metal layer formed from aluminum, gold or antimony deposited under vacuum and entirely covering the design on the side of the design remote from the carrier sheet, the metal layer covering the entire area of the lacquer-release layer other than the area of said lacquer-releast layer having the design thereon, and an adhesive layer formed of a heat softenable material disposed on the metal layer on the side of the metal layer remote from the carrier sheet and on only part of the metal layer, namely on that part where it is intended that the design be transferred.
References Cited UNITED STATES PATENTS 2,017,367 10/1935 Kurz 1173.3 2,099,641 11/1937 Bach et al 1173.3 X 2,159,693 5/1939 Gaylord 1173.4 2,190,405 2/ 1940 Humphner 1173.4 X 2,351,933 6/1944 Decker et al 117-3.1 X 2,684,918 7/1954 Oughton 1173.3 2,746,877 5/ 1956 Matthes 117-3.4 X 2,758,035 8/ 1956 Matthes l17-3.6 2,941,916 6/ 1960 Akkeron 1173.6 X 3,235,395 2/1966 Scharf 1173.4 X 3,463,651 8/1969 Warsager 1173.3 1,882,593 10/1932 Hentschel 1173.3 X
FOREIGN PATENTS 816,022 6/ 1969 Canada 1l73.l
WILLIAM D. MARTIN, Primary Examiner H. J. GWINNELL, Assistant Examiner US. Cl. X.R. 117-45