In the field of plastic molding such as cosmetic containers, bookbinding, or commercial printing, metallic appearance or an expensive look which cannot be expressed merely by common printing, has been given to a product by conducting a printing processing treatment called as foil stamping on the surface of the base material, by which a character or a picture image formed with a gold, silver or colored foil is transferred onto the surface. By this foil stamping which is also called hot stamping, a foil is transferred using heat and pressure on various base materials such as paper, plastics or leather. This method is one of the most suitable methods to achieve a metallic gloss. Specifically, in this method, a transfer material layer having a foil formed on a plastic support is brought in contact with a base material, and, then, the foil of the transfer material layer is transferred to a base material to form a foil image by conducting thermo-compression using a metal press mold.
In a transfer foil used for the foil stamping, for example, a protective layer, a transfer material layer and an adhesive layer are provided on a releasing agent layer formed on a plastic support made of such as a polyester film, in which the transfer material layer is formed by vacuum evaporated metal or an ink. The technique to produce a transfer foil has been improved in accordance with the enlargement of the market of the transfer foil. For example, researches on a transfer foil having a protective layer containing an organic silicon compound and a reactive organic compound in view of improving the durability of a foil image and on a transfer foil having an electron beam curable adhesive layer by which a stronger protective layer is formed by being irradiated with an electron beam after peeled from the support, have been brought forward (for example, refer to Patent Documents 1 and 2).
In recent years, a hologram is often attached on, for example, a cash card or a credit card in order to prevent falsification or alteration, or for the security of these cards. Such a hologram used for the prevention of falsification of a card has been formed mainly by employing a technique of foil transferring. Since many of these transfer images used for the prevention of falsification or for security of the cards contain a precise pattern, it is required to accurately transfer the image but not to cause a problem such as a burr or missing of the foil. In accordance with such a requirement, there has been examined a transfer foil by which, by incorporating a polymer liquid crystal material in a transfer layer, a precise-shaped label is accurately transferred without causing defects such as burrs or missing of the foil (for example, refer to Patent Documents 3).
On the other side, in order to conduct foil transfer on a base material with a simple process and to stably hold the transferred foil for a long time, advanced has been a technique to form a resin layer on the surface of a base material and to provide a transfer foil on the resin layer, followed by conducting a heat treatment to carry out foil transfer. For example, there has been proposed a technique to form an ink layer on the base material of a product using an emulsion ink in which a hot melt adhesive agent is dispersed and to provide a transfer foil on the ink layer, followed by conducting a heat treatment to carry out foil transfer (for example, refer to Patent Document 4).
Also, proposed has been a technique to form a resin layer on a base material using a toner and to conduct foil transfer via a hot stamp technique using the resin layer as a binder. For example, there has been a technique to transfer a foil on a three dimensional image by forming a protrusion image or a design image on a base material using a toner and placing an adhesive layer of a transfer foil on the toner image surface, followed by heat-pressing with a roller (for example, refer to Patent Documents 5 and 6). Further, there has been a technique regarding a transfer foil having a toner image formed with a dry toner on a substrate, in which a picture image is formed in the toner layer using a printer, followed by transferring onto a base material (for example, refer to Patent Document 7). The techniques given in these patent documents may enable to thermo-compress a transfer foil on the surface of a base material without using a metal pressing member called a press mold. This means that these techniques have intended to improve working efficiency by reducing necessary time for the foil transferring.
USPTO Backgrounds
USPTO Backgrounds