JP2011218619A - Magnetic transfer sheet with optical diffraction structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic transfer sheet with an optical diffraction structure easily forming a magnetic information recording part with an optical diffraction structure by transfer.SOLUTION: In this magnetic transfer sheet with an optical diffraction structure, at least a strippable protective layer, an optical diffraction structure formation layer, a barrier layer, a light reflective layer formed of a tin thin film of a sea-island structure, a magnetic information recording layer and an adhesive layer are laminated on a support body in this relative order; the barrier layer is formed of a thin film of an inorganic compound having a gas barrier property; and the refractive index thereof is set higher than that of the optical diffraction structure formation layer.

Description

  The present invention relates to a magnetic transfer sheet with a light diffractive structure that can easily form a magnetic information recording part with a light diffractive structure having a desired brightness and excellent gas barrier properties by transfer.

  Conventionally, in order to prevent forgery of securities such as cards and gift certificates, various forms of light diffractive structures including holograms that are difficult to forge and can be determined at a glance are authentic. It is used in. In recent years, these optical diffraction structures have been affixed to various products such as personal computer parts, equipment parts, sports equipment, etc., so that they can be clearly recognized as genuine products, and it is difficult to distribute counterfeit products. It is going to be performed actively.

  On the other hand, magnetic cards such as credit cards and cash cards are widely known as magnetic information recording media. Even in these magnetic cards, it is very important that measures for preventing tampering and forgery are taken, and the optical diffraction structure such as the hologram described above is pasted on a part thereof to prevent forgery. There are many cases.

  However, these magnetic cards are strictly regulated by the standard, such as the shape and the position where the magnetic recording unit is provided, and the magnetic information recording unit is provided in a limited space, where the use, owner, expiration date, etc. It is necessary to record such magnetic information and to have design characteristics suitable for a card. However, the optical diffractive structure to be pasted as a forgery prevention measure is limited in the pasting space, and it is difficult to express a design suitable as a card.

  As one means for solving such a problem, a magnetic tape in which optical diffraction structures such as holograms are laminated and integrated, and a magnetic card manufactured using the magnetic tape have been proposed (for example, patents). Reference 1).

  This magnetic card has a light diffraction structure for expressing color changes due to light diffraction and has a light reflection layer made of a metal thin film with high light reflectivity. Since the layer is made of metal, the entire layer is electrically conductive. For this reason, when static electricity is charged in a card having such a light reflection layer of a metal foil film, it is possible to discharge from one point of the card instantaneously through this light reflection layer to generate a spark, and to read magnetic data. The writing may become unstable or the magnetic data reader may be damaged.

  Corresponding to such a situation, in recent years, a configuration in which a light-reflective metal thin film is arranged in an island shape and a sea-island structure deposited thin film (tin deposited thin film) that does not exhibit electrical conductivity is provided. Have been proposed (see, for example, Patent Document 2).

  However, the sea-island-structured tin-deposited thin film is provided with fine grains so as not to exhibit electrical conductivity, so the light reflectivity is impaired in the so-called sea area, which is the gap between grains, and the expected brightness Could not be expressed. In addition, the sea-island-structured tin thin film also has the disadvantage of poor resistance to water vapor and the like.

JP-A-6-167920 JP 2008-15071 A

  The present invention has been made in view of the situation as described above, and the problem is that on the support, at least a peelable protective layer, a light diffraction structure forming layer, a barrier layer, and a sea-island-structured tin thin film. The light reflection layer, magnetic recording layer, and adhesive layer are laminated in this relative order, causing problems such as discharge of static electricity and unstable reading and writing of magnetic data and failure of the magnetic data reader. It is another object of the present invention to provide a magnetic transfer sheet with a light diffraction structure which is made up of the low light reflectivity of the tin-deposited thin film having a sea-island structure and can be prevented from being oxidized by water vapor.

  In order to solve the problems as described above, the invention according to claim 1 is a light reflection device comprising at least a peelable protective layer, a light diffraction structure forming layer, a barrier layer, and a sea-island tin thin film on a support. Layer, magnetic information recording layer, and adhesive layer are laminated in this relative order, and the barrier layer is made of a thin film of an inorganic compound having gas barrier properties, and its refractive index is set higher than that of the light diffraction structure forming layer. A magnetic transfer sheet with a light diffraction structure.

  The invention according to claim 2 is the magnetic transfer sheet with a light diffraction structure according to claim 1, wherein the barrier layer is made of any of oxides or nitrides of metals selected from silicon, aluminum, tin, and titanium. The layer thickness is set in the range of 5 nm to 500 nm.

  In the magnetic transfer sheet of the present invention, a barrier layer having a higher refractive index than the light diffraction structure formation layer and excellent in gas barrier properties is provided between the light diffraction structure formation layer and the light reflection layer. Since the light reflectivity of the thin light reflection layer is improved and oxidation due to water vapor can be prevented, a magnetic information recording unit with a light diffraction structure with excellent brightness and durability is applied to a predetermined transfer target. It becomes possible to transfer and form.

It is explanatory drawing which shows the general | schematic planar state of the magnetic card | curd which has the magnetic information recording part with a light diffraction structure produced using the magnetic transfer sheet with a light diffraction structure of this invention. It is explanatory drawing which shows the general | schematic cross-section structure of one Embodiment of the magnetic transfer sheet with a light diffraction structure of this invention.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 2, the magnetic transfer sheet with a light diffractive structure of the present invention has at least a peelable protective layer 32, a light diffractive structure forming layer 33, a barrier layer 34, and a sea-island structure tin thin film on a support 31. The light reflecting layer 35, the magnetic information recording layer 36, and the adhesive layer 37 are laminated in this relative order. The barrier layer 34 is made of a thin film of an inorganic compound having a gas barrier property, and its refractive index is a light diffraction structure. It is set higher than the formation layer 33.

As the support 31, a polyethylene terephthalate resin film having a stable thickness and high heat resistance is generally used, but is not necessarily limited thereto. As other materials, films having high heat resistance such as polyethylene naphthalate resin films and polyimide resin films can be used. Also, other films such as polyethylene, polypropylene, heat-resistant vinyl chloride, etc. may be used as long as they can satisfy the coating material application conditions and the drying conditions for each layer provided on the film. Is possible.

  Moreover, when it becomes difficult to peel off the peelable protective layer 32 described later at the time of transfer, a release layer may be provided on the surface of the support 31 on which the peelable protective layer 32 is formed. . Moreover, when peeling is too light, you may adjust so that an easily bonding process may be performed and peelability may be settled in an appropriate range. In addition, an antistatic treatment, a mat treatment, an emboss treatment, or the like may be performed as long as the transferability is not affected.

  Such a peelable protective layer 32 provided on the support 31 is a layer which is peeled off at the interface with the support 31 and is transferred together with other layers to the transfer target, and transferred to the transfer target. In some cases, the optical diffraction structure layer 33, which will be described later, is covered so as to prevent adverse effects on mechanical damage, external damage related to rubbing during carrying, etc. and living substances (such as liquor and water). I'm in charge.

  Examples of the constituent material of the peelable protective layer 32 include various resins such as a thermosetting system, a moisture curing system, an ultraviolet curing system, and an electron beam curing system. About 20 parts by weight of a lubricant may be added to these resins for the purpose of imparting friction resistance.

  On the other hand, the light diffractive structure forming layer 33 is a layer that expresses a color due to light diffraction, and is formed by, for example, forming an uneven pattern of about 50 nm to 2000 nm with a press plate. The main constituent materials include thermoplastic resins, thermosetting resins, ultraviolet rays or electron beam curable resins. More specifically, polyisocyanate is added as a crosslinking agent to a thermoplastic resin such as an acrylic resin, an epoxy resin, a cellulose resin, a vinyl resin, an acrylic polyol or a polyester polyol having a reactive hydroxyl group, and then crosslinked. Examples thereof include thermosetting resins such as urethane resins, melamine resins, and phenol resins, and ultraviolet or electron beam curable resins such as epoxy (meth) acryl and urethane (meth) acrylates. These may be used alone or in combination.

  As described above, the light diffractive structure forming layer 33 is pressed into a concavo-convex shape that becomes a light diffractive structure such as a hologram. The uneven structure is provided in a shape having a pitch of about 5 nm to 2000 nm and a depth of about 20 nm to 500 nm.

  The barrier layer 34 provided on the light diffraction structure forming layer 33 is used to improve the light reflectivity of the light reflection layer 35 made of a tin thin film having a sea-island structure and to prevent oxidation due to water vapor. The layer is provided and is made of an inorganic oxide having a refractive index higher than that of the light diffraction structure forming layer 33 and excellent in gas barrier properties.

Examples of the thin film forming material having high gas barrier properties include oxides or nitrides containing one or more metals selected from Si, Al, In, Sn, Zn, Ti, Cu, and the like. In these, the oxide or nitride containing the metal chosen from Si, Al, Sn, and Ti is used preferably. Among them, examples of the material having a high refractive index include TiO ₂ (2.6) SiO (2.0), Si ₂ O ₃ (2.5), and Al ₂ O ₃ (1.6). Here, the numerical value in parentheses following the chemical formula is the respective refractive index n.

Using these materials, a thin film having a thickness of about 5 nm to 500 nm may be provided by a vacuum deposition method, a sputtering method, a CVD method, or the like to form the barrier layer 34. If the layer is too thick, cracks are generated by applying bending stress, and if the layer is too thin, the film is distributed in an island shape without forming a layer, resulting in poor gas barrier properties such as water vapor barrier properties. Therefore, 10 nm to 200
It is desirable to provide a thickness of about nm. Alternatively, the above-described materials may be used by being stacked in two or more layers.

  The light reflecting layer 35 made of a tin film having a sea-island structure provided on such a barrier layer 34 mainly makes the reading and writing of magnetic data unstable due to discharge of static electricity or reading of magnetic data. This layer is provided to prevent the device from being damaged.

  The light reflection layer 35 made of a tin thin film having such a sea-island structure can be formed by controlling the evaporation rate, the film layer thickness, and the like in vacuum deposition or the like. Here, the sea-island structure is a thin film layer with a structure in which individual islands are arranged independently in the part that is regarded as the other sea when a small thin film made of tin is regarded as an island. Each island is not connected. The interval between the islands may be about 10 nm to 1000 nm, but more preferably about 10 nm to 500 nm.

The magnetic information recording layer 36 provided on the light reflecting layer 35 made of such a sea-island-structured tin-deposited thin film is composed of γ-iron oxide, magnetite, cobalt-coated γFe ₂ O ₃ , barium ferrite, chromium dioxide. This is a layer formed by coating a magnetic paint prepared by dispersing magnetic powder such as iron-based metal magnetic powder in a binder with a thickness of about 5 to 20 μm.

  Surfactants, plasticizers, waxes, carbon black and fillers can be added to the magnetic coating as necessary.

  An adhesive layer 37 is provided on such a magnetic information recording layer 36, and heat and pressure are applied in contact with various transferred materials (for example, paper / plastic film). Thus, the layer has a function of transferring and adhering to the transfer target side.

  As a specific constituent material, a heat-sensitive adhesive material such as a thermoplastic resin is used. And what is necessary is just to provide with the thickness of about 1-10 micrometers by the well-known coating method.

  Examples of the present invention will be described below.

  A peelable protective layer having a thickness of 1 μm was applied and formed on one surface of a transparent polyethylene terephthalate film (support) having a thickness of 25 μm by a gravure coating method using a material for forming a peelable protective layer having the following composition.

  Next, a thin film having a thickness of 2 μm was applied and formed on the peelable protective layer by a gravure coating method using a material for forming an optical diffraction structure forming layer having the following composition. Then, the thin film was subjected to a molding process by a roll embossing method using a nickel press plate with an uneven shape of the light diffraction structure impressed on the thin film to obtain a light diffraction structure forming layer.

Subsequently, a thin film of silicon oxide (Si ₂ O ₃ ) was vapor-deposited at 10 nm on this light diffraction structure forming layer by a vacuum vapor deposition method to provide a barrier layer. On this barrier layer, a thin film of tin (Sn) sea-island structure was vapor-deposited by a vacuum deposition method, and a light reflection layer made of a tin thin film of sea-island structure was provided. The island portion of the light reflecting layer was 100 nm, and the interval was 10 nm.

On the light reflecting layer, a magnetic information recording layer was provided by applying a thin film having a thickness of 8 μm by a microgravure method using a material for forming a magnetic information recording layer having the following composition. Finally, a thin film having a thickness of 2 μm is applied onto the magnetic information recording layer by a gravure coating method using a material for forming an adhesive layer having the following composition to provide an adhesive layer. A transfer sheet was obtained.

[Material for forming peelable protective layer]
Acrylic resin 15 parts Polyethylene WAX 1 part Methyl ethyl ketone 50 parts Toluene 34 parts [Material for forming optical diffraction structure forming layer]
Vinyl chloride-vinyl acetate copolymer 15 parts Urethane resin 10 parts Methyl ethyl ketone 50 parts Toluene 25 parts [Material for forming magnetic information recording layer]
γFe ₂ O ₃ magnetic powder 30 parts Vinyl acetate copolymer 3 parts Polyurethane elastomer 20 parts Methyl ethyl ketone 15 parts Toluene 15 parts [Material for forming adhesive layer]
Polyester resin 20 parts Ethyl acetate 60 parts Butyl acetate 20 parts

<Comparative example>
A magnetic transfer sheet with a light diffraction structure for comparison was produced in the same manner as in the example except that the barrier layer was not provided.

  The magnetic transfer sheets according to the examples and the comparative examples obtained as described above are arranged so that the adhesive layer is in contact with the card base made of polycarbonate, and then the support of the magnetic transfer sheet (PET film) After heating and pressing from the side), the support was peeled off, and a magnetic card in which a magnetic information recording part with a light diffraction structure was partially provided as shown in FIG.

  And evaluation of the brightness feeling by external appearance observation of each magnetic card produced as mentioned above and external appearance evaluation of the magnetic card | curd after preserve | saving for 1 week on 95 degreeC-95% humidity conditions were performed. Table 1 shows the evaluation results.

  As can be seen from Table 1, the magnetic card produced using the magnetic transfer sheet with a light diffraction structure according to the example is light behind the portion corresponding to the sea of the light reflection layer made of a tin thin film having a sea-island structure. Since the reflective high-refractive-index barrier layer is located, the brightness is higher than that of the magnetic card manufactured using the magnetic transfer sheet with a light diffraction structure according to the comparative example, and the entry of water vapor is prevented. For this reason, there was no discoloration of the light reflecting layer made of a tin thin film even under high temperature and high humidity conditions.

The magnetic transfer sheet with a light diffraction structure of the present invention is suitably used for the production of a magnetic information recording medium such as a cash card, a credit card, a passbook, etc., and prevents problems caused by static electricity of the magnetic information recording medium obtained by using the magnetic information recording sheet. In addition, a highly durable light diffraction structure can be imparted to a part thereof.

DESCRIPTION OF SYMBOLS 1 Magnetic information recording part 31 with a light diffraction structure Support body 32 Peelable protective layer 33 Light diffraction structure formation layer 34 Barrier layer 35 Light reflection layer 36 Magnetic information recording layer 37 Adhesive layer

Claims (2)

  On the support, at least a peelable protective layer, a light diffraction structure forming layer, a barrier layer, a light reflecting layer composed of a tin thin film having a sea-island structure, a magnetic information recording layer, and an adhesive layer are laminated in this relative order. The magnetic transfer sheet with a light diffraction structure, wherein the barrier layer is made of a thin film of an inorganic compound having gas barrier properties, and the refractive index thereof is set higher than that of the light diffraction structure forming layer.   The barrier layer is made of either an oxide or a nitride containing a metal selected from silicon, aluminum, tin, and titanium, and the layer thickness is set in a range of 5 nm to 500 nm. The magnetic transfer sheet with a light diffraction structure according to 1.

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