JPS61185500A - Thermal transfer foil - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a thermal transfer foil, and more particularly, it can be used to cover letters, numbers, designs, etc. printed on a substrate such as a lottery ticket. The present invention relates to a thermal transfer foil that can be used as a thermal transfer foil.

(Prior Art) A conventional thermal transfer foil has a thermal adhesive layer, an opaque decorative layer, a release layer, and a carrier laminated in this order. The decorative layer is
It can consist of a protective lacquer layer and a metal layer, which is usually a vacuum-deposited layer. In use, the thermal transfer foil is stamped onto the substrate to be decorated, with the thermal adhesive layer facing the substrate.

The stamp that presses the thermal transfer foil onto the substrate can be of a specific shape. Heating the stamp then activates the thermal adhesive layer and adheres the decorative layer of the thermal transfer foil onto the substrate, while the release layer releases the carrier from the rest of the thermal transfer foil. In conventional thermal transfer foils, the thermal adhesive layer is configured such that the device layer adheres as firmly as possible to the substrate after hot stamp removal and cooling.

In certain cases, for example, in lottery tickets, overprinting is applied to numbers, letters, or specific designs, so that the covered numbers, etc. cannot be distinguished and can be easily printed without damaging the surface of the overprinted substrate. It is necessary to be able to rub off this overprinting. Until now, such conditions have been achieved in conventional printing presses by using special printing colors. However, such methods are not always applicable, especially when soft, hygroscopic papers are used as substrates. Furthermore, known overprinting methods considerably limit the appearance of the overprint.

(Problems to be Solved by the Invention) In view of the above-mentioned drawbacks of the conventional method used for overprinting lottery tickets, etc., the present invention provides a coating method to prevent the figures on the lottery ticket from being easily identified. can,
Moreover, it is an object of the present invention to provide a thermal transfer foil whose coating layer can be easily removed.

(Means for solving the problems) The thermal transfer foil according to the present invention has a thermal adhesive layer,
An opaque decorative layer, a release layer and a carrier are laminated in this order, and the thermal adhesive layer is a waxy layer having a thickness of at least 5 μm, usually 5.0 to 20 μm, preferably 6 to 18 μm. It is characterized by certain things.

Thermal transfer foils with this configuration are practically applicable to all types.

It can be used on similar substrates, and can also be used on hygroscopic substrates. This is because the device s is relatively homogeneous and there is no risk of it penetrating into the substrate when coating designs etc. on the substrate. A waxy thermal adhesive layer is highly suitable for adhering the device to the substrate. However, if necessary, the decorative layer can be easily rubbed off, for example by rubbing with a coin or a fingernail, without damaging the original design on the substrate, ie the design covered by the transfer foil. Since there are no practical restrictions on the composition of the decorative layer in the thermal transfer foil of the present invention, the color of this layer should be sufficiently compatible with the color of the substrate, and the design etc. printed on the substrate and covered with the transfer foil should be It can be configured to have such a density that it cannot actually be discerned even when viewed through a light source. Accordingly, the thermal transfer foil of the present invention is a good alternative to the overlap method commonly used to temporarily hide designs printed on certain types of substrates, such as lottery tickets.

Preferably, the waxy thermal adhesive layer of the thermal transfer foil according to the invention is composed of at least one synthetic wax dispersion, a solvent and at least one pigment.

For example, using a synthetic wax dispersed in a volatile liquid, a waxy layer can be printed on a decorative layer using a conventional printing machine, and this waxy layer can also be used as an adhesive layer. The advantage is that it can be cured sufficiently to allow for. This thermal adhesive layer has, for example, the following composition: 20% heterocyclic wax dispersion 25
~45 parts by weight 24% polyethylene wax dispersion 4-1
0 parts by weight Ethylene-vinyl acetate copolymer 4 to 10 parts by weight Toluene 10 to 20 parts by weight Ethyl acetate 5 to 8 parts by weight Pigment
It may consist of 30 to 40 parts by weight. Pigments help to make the decorative layer opaque and are therefore particularly useful in hiding originally printed designs.

The decorative layer can be of various configurations.

The simplest decorative layer 1 is commonly used in thermal transfer foils.

A colored lacquer layer consisting of lacquer.

The decorative layer can also be of two-layer construction, consisting of a protective lacquer layer facing the carrier side and a metal layer arranged between this protective lacquer layer and the thermal adhesive layer. Such a decorative layer has a particularly good appearance and is therefore suitable for use in lottery tickets. Furthermore, a metal layer of sufficient thickness is very effective in hiding the original print on the substrate. In such a case, the metal layer is preferably a vacuum-deposited layer.

In order to hide the original print more completely, it is preferable to apply a particularly irregularly shaped print pattern to the decorative layer. In such cases, even if the decorative layer is somewhat transparent, the printed pattern makes the original print on the substrate completely indistinguishable.

(Example) The thermal transfer foil of the present invention can be basically manufactured by the same method as the conventional method. That is, it can be manufactured by sequentially printing the peeling layer 111WJ, the decorative layer, J3 and the thermal adhesive layer on a carrier, where the thermal adhesive layer is a molten wax or a wax dispersion. Typically the carrier is a polyester foil approximately 20 μm thick.

The release layer is easily removable from the carrier and can consist of a very thin wax layer or a relatively thin lacquer layer. The thickness of the release layer is usually 0.01 to 1
It's a μ helmet.

The decorative layer can also consist only of a pigmented lacquer layer with a thickness of 3 to 10 .mu.m, but according to another embodiment a protective lacquer layer of 1 to 3 .mu.m thick is applied after curing on top of this by 0.05 .mu.m. A metal layer of 0.02 to 0.6 .mu.m, preferably about 0.04 .mu.m, can also be deposited. The protective or colored lacquer layer of the decorative layer can be selected from the known lacquers used for the production of thermal transfer foils, such as acrylic resin, nitrocellulose, etc. lacquers. The metal layer is typically a vacuum deposited aluminum layer, which may be directly colored or coated with a protective transparent lacquer layer with a certain shade to mimic the particular metal. It is of course also possible for the gold layer to consist of other metals commonly used in the production of metallized thermal transfer foils.

If the decorative layer is provided with a printed pattern, such printed pattern may be provided in a separate layer.

However, it goes without saying that it is equally possible to have a single layer exhibiting a printed pattern. These are known techniques.

The most distinctive part of the thermal transfer foil according to the present invention is the thermal adhesive layer. The thermoadhesive layer may be printed directly onto the decorative layer, especially if the decorative layer is a pigmented lacquer layer, or with an intervening tie coat. Tie coats are often necessary when the decorative layer has a metal layer as an adjacent layer to the thermal adhesive layer. Such tie coats are also known in the production of transfer foils, and most of them are composed of specific synthetic resins.

Typically, thermal adhesive layers are composed of various types of waxes, solvents, and pigments.

According to a preferred embodiment of the invention, the thermal adhesive layer has a thickness of 6 to 1
It is applied as a layer of 8 μm, i.e. 10-30 g/Tli, and has the following composition: 20% wax goldstone heterocyclic wax dispersion (melting point 94° C.) 38 parts by weight polyethylene wax dispersion with wax content 24% System (melting point: 140°C): 4 parts by weight ethylene/vinyl acetate copolymer (melting point: 90°C): 10 parts by weight Toluene: 12 parts by weight Ethyl acetate: 6 parts by weight Color pigment: 30 parts by weight. For use as a waxy thermoadhesive layer, the components described above are carefully mixed and printed in the usual manner on a carrier already provided with a release layer and a decorative layer and, if necessary, a tie coat. In this case, the usual printing methods, in particular the so-called reverse roller method (reverse, 5e-
r.

1 ler-method) J can be used.

The drawings show different embodiments of the thermal transfer foil according to the invention.

The first thermal transfer foil, the cross section of which is shown in FIG.
Consisting of The carrier 11 is typically a polyester foil approximately 20 μm thick. This carrier is coated with a 0.0-thick layer of wax or special lacquer in a first printing step.
A release layer 12 of 1-1 μm is applied. A protective lacquer layer 13 is then applied in a new printing step.

This protective lacquer layer may have a printed pattern and is preferably transparent but may also be colored. The protective lacquer layer is a conventional lacquer layer with a thickness of 1 to 3 μm. After the protective lacquer layer 13 has dried, a metal layer 14, namely an aluminum layer with a thickness of 0.02 to 0.06 .mu.m, preferably about 0.04 .mu.m, is applied by vacuum evaporation. A tie coat 15 consisting of a special lacquer is then applied to the metal layer, and this tie coat 1
A thermal transfer foil is completed by printing a wax-like thermal adhesive layer 16 on 5. The thermal adhesive layer has a composition as described above, for example, and has a thickness of 5 to 20 μm, preferably 6 μm.
~18 μm.

FIG. 2 shows a thermal transfer foil different from the embodiment shown in FIG. The decorative layer in the embodiment shown in FIG. 1 consists of a protective lacquer 1i 113, a metal layer 14 and a tie coat 15, whereas the thermal transfer foil in FIG. 2 has a single decorative layer 23 consisting of a colored lacquer layer. are doing. This lacquer layer has a conventional composition, for example an acrylic resin lacquer which has been made opaque by the addition of sufficient pigments. The thickness of this lacquer layer is approximately 3-10 μm. This colored lacquer layer 23 is also covered with protective lacquer W! A print pattern can be applied in the same way as J13.

The carrier 21 basically corresponds to the carrier 11 of FIG. Similarly, the peeling layer 22 and the thermal adhesive layer 26 are also applied to the peeling layer 112 and thermal bonding W! of FIG. It is basically the same as 116.

(Effects of the Invention) As described above, the thermal transfer foil according to the present invention can be effectively used to temporarily cover designs on a substrate so that they cannot be identified. The thermal adhesive layer ensures sufficient adhesion to the substrate. However, the decorative layer, whether it is a metal layer or a colored lacquer layer, can be easily removed from the substrate by rubbing with a coin or a fingernail without damaging the surface of the substrate.

Therefore, the thermal transfer foil of the present invention makes it possible to overprint lottery tickets and the like even in cases where conventional printing methods are not applicable, and its utility value is extremely high.

[Brief explanation of drawings]

1 and 2 are schematic cross-sectional views showing two different embodiments of the thermal transfer foil of the present invention. 11.12--Carrier (thickness approximately 20 μm) 12.22
-... Peeling layer (thickness 0.01-1 μm) 13... Protective lacquer layer (thickness 1-3 μm) 14-... Metal layer (Ig
thickness 0.02 to 0.06 μm) 15... Tie coat (thickness less than 1 μm) 16.26... Thermal adhesive layer (thickness 5 μm)
Above) 23... Colored lacquer layer (thickness 3-10 μm)
Figure 1 Figure 2

Claims (10)

[Claims] (1) A thermal adhesive layer, an opaque decorative layer, a release layer, and a carrier are laminated in this order, and the thermal adhesive layer has at least five
A thermal transfer foil characterized in that it is a wax-like layer with a thickness of μm. (2) The thermal transfer foil according to claim 1, wherein the thermal adhesive layer has a thickness of 5 to 20 μm. (3) The thermal transfer foil according to claim 2, wherein the thermal adhesive layer has a thickness of 6 to 18 μm. (4) the thermal adhesive layer is at least one synthetic wax dispersion system;
Thermal transfer foil according to any one of claims 1 to 3, characterized in that it consists of a solvent and at least one pigment. (5) The thermal adhesive layer has the following composition: 20% heterocyclic wax dispersion system 25 to 45 parts by weight 24
% Polyethylene wax dispersion 4 to 10 parts by weight Ethylene-vinyl acetate copolymer 4 to 10 parts by weight Toluene
The thermal transfer foil according to claim 4, comprising 10 to 20 parts by weight of ethyl acetate, 5 to 8 parts by weight, and 30 to 40 parts by weight of pigment. (6) The thermal transfer foil according to any one of claims 1 to 5, wherein the decorative layer is a colored lacquer layer. (7) The decorative layer consists of a protective lacquer layer facing the carrier side and a metal layer arranged between this protective lacquer layer and the thermal adhesive layer. The thermal transfer foil according to any one of item 5. (8) The thermal transfer foil according to claim 7, wherein the metal layer is a layer formed by vacuum deposition. (9) The thermal transfer foil according to any one of claims 1 to 8, wherein the decorative layer has a printed pattern. (10) The thermal adhesive layer is formed by applying molten wax or a wax dispersion to the carrier on which the decorative layer has already been applied. The thermal transfer foil according to any one of item 9.