JP2001328376A - Information recording medium and transfer sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transfer sheet capable of readily forming a structure, improving the durability of a hologram or the like and facilitating the observation of a record on a re-writable layer, on a substrate, in an information recording medium provided with a light diffraction structure, such as the hologram or the like, and the re-writable layer which are formed on the substrate so as to be superposed. SOLUTION: The purpose can be achieved by the information recording medium provided on the substrate 1 with an adhesive agent layer 7, a light reflective layer 2, the light diffraction structure 3, the re-writable layer 5 and a protective layer 6 which are laminated sequentially. On the other hand, the transfer sheet for preparing the information recording medium is obtained by forming the protective layer 6, the re-writable layer 5, the light diffraction structure 3, the light reflective layer 2 and the adhesive agent layer 7 sequentially on a sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rewritable type such as a transparent / opaque type of polymer / organic low molecular weight dispersion or a leuco dye or a liquid crystal on a light diffraction structure such as a hologram. The present invention relates to an information recording medium such as a card having an information recording section in which (= rewritable) color-forming layers are overlapped.

[0002]

2. Description of the Related Art Various information recording media for recording individual information updated each time in a visible state are known.
For example, in the retail business, the number of points and other information are recorded on the surface of a card in order to give points according to the purchase amount of a customer and to give preferential treatment according to the points. Alternatively, the information recorded on the magnetic recording layer or the IC module of the information recording medium is displayed in a visible state.

[0003] The term "card" is a commercial point of view in which global agreements are made between concerned parties.
54mm x 86mm, unified to the size of a business card
Refers to the degree.

[0004] Incidentally, information recorded on an information recording medium has an economic value or other value directly or indirectly, and thus is likely to be an object of forgery or falsification of a person making an illegal attempt. , On the side that issues information recording media,
Various countermeasures against counterfeiting and alteration have been taken.

[0005] One of the typical countermeasures for preventing forgery and alteration is the use of holograms. Holograms were previously replicated by recording light interference fringes on an emulsion layer on a glass dry plate, but recently the interference fringes are recorded as irregularities on the surface of the photosensitive resin layer or as high or low density. As a result, the hologram was copied onto an information recording medium, such as a card, to ensure that the information recording medium was genuine. Have been.

Therefore, in order to ensure the authenticity of an information recording medium that records individual information updated each time in a visible state, application of a hologram has been attempted. For example,
JP-A-8-207444 discloses a base material / a reflective thin film layer / a reversible thermosensitive recording layer / a hologram-forming layer having fine irregularities and a transparent thin film layer having a refractive index different from that of the hologram on the minute irregularities. It describes a recording medium comprising a protective layer, and it is said that the hologram has excellent design and anti-tampering properties.

However, according to the above invention, since the hologram is formed near the surface, the hologram is liable to be stained or damaged during repeated use, so that the visibility of the hologram is liable to decrease, and furthermore, the lower layer of the hologram is formed. Since reversible thermosensitive recording is performed, it is necessary to view through the hologram image covering the recorded characters and the like, and there is a disadvantage that the visibility of the recorded characters and the like is lowered, and conversely,
Considering the visibility of the recorded characters and the like, the hologram image has to be simplified.

[0008]

SUMMARY OF THE INVENTION In the present invention, a hologram or other optical diffraction structure and a rewritable layer are formed on a base material so as to improve the durability of the hologram and to record the rewritable layer. The purpose is to make it easy to see. Another object of the present invention is to provide a transfer sheet capable of easily forming such a stacked structure on a substrate.

[0009]

In the present invention, the conventional problem is solved by laminating an optical diffraction structure such as a hologram on the side closer to the base material of the information recording medium and laminating a rewritable layer thereon. Was completed. Further, by using a transfer sheet in which a rewritable layer and an optical diffraction structure are sequentially formed on a base material, the above-mentioned information recording medium can be efficiently produced.

According to a first aspect of the present invention, a light diffraction structure comprising at least a light reflecting layer and a light diffraction structure layer is laminated on a substrate, and a rewritable layer is laminated on the light diffraction structure. The present invention relates to an information recording medium characterized in that In a second aspect, in the first aspect,
An information recording medium, wherein an adhesive layer is interposed between the substrate and the light diffraction structure. A third invention relates to the information recording medium according to the first or second invention, wherein a protective layer is laminated on the rewritable layer. The fourth invention is characterized in that a rewritable layer and a transfer layer composed of a light diffraction structure layer and a light reflective layer are laminated on the peelable surface of the peelable sheet having one surface being a peelable surface. Transfer sheet to be transferred. A fifth aspect of the present invention is the transfer sheet according to the fourth aspect, wherein the releasable sheet comprises a sheet-like substrate and a releasable layer laminated on one surface of the sheet-like substrate. . A sixth invention relates to the transfer sheet according to the fourth or fifth invention, wherein an adhesive layer is laminated on an exposed surface side of the light reflective layer of the transfer layer. The seventh invention is
The transfer sheet according to any one of the fourth to sixth inventions, wherein a protective layer is laminated on the transfer layer on the side of the peelable layer.

[0011]

1 and 2 are sectional views showing the structure of an information recording medium of the present invention, and FIG. 3 is a sectional view of a transfer sheet for manufacturing the information recording medium. The information recording medium 10 of the present invention basically includes, as shown in FIG.
A light diffraction structure 4 including a light reflective layer 2 and a light diffraction structure layer 3 is laminated on a base material 1, and a rewritable layer 5 is laminated on the light diffraction structure 4. The light diffraction structure 4 and the entire rewritable layer 5 are partially buried in the substrate 1, and the upper surface of the rewritable layer 5 is flush with the upper surface of the substrate 1.

In practice, various layers are often added in consideration of production efficiency and product properties. As shown in FIG. The adhesive layer 7 may be laminated between the protective layer 6 and the protective layer 6 on the uppermost layer. In this case, the upper surface of the protective layer 6 is flush with the upper surface of the substrate 1. In the above description with reference to FIGS. 1 and 2, the light diffraction structure 4 and the rewritable layer 5 are laminated on a part of the substrate 1. Alternatively, the substrate 1 may be laminated not only on one side but also on both sides. Hereinafter, the information recording medium 10 of the present invention will be described in more detail.

As the substrate 1, polyester such as polyvinyl chloride, polyethylene terephthalate or polyethylene naphthalate, polycarbonate, polyamide,
Polyimide, cellulose diacetate, cellulose triacetate, polystyrene, acrylic, polypropylene, polyethylene, ABS and other resin sheets,
Metal such as aluminum and copper, paper, and impregnated paper such as resin or latex or the like, or a composite sheet can be used. When heat resistance is required, a sheet of an amorphous polyester resin or a blend resin of an amorphous polyester resin and a polycarbonate resin can be used as the substrate 1.

The thickness of the substrate 1 varies depending on the material, but is usually in the range of about 10 μm to 5 mm. The information recording medium 10 also serves as a magnetic card, and the base material 1 is
To comply with the standard, the thickness is 0.7
6 mm. When the base material 1 is formed of polyvinyl chloride (hereinafter, PVC), usually, a white PVC sheet having a thickness of 280 μm is used as a core sheet, two of which are stacked, and a transparent PVC sheet having a thickness of 100 μm is provided on both sides thereof. Are stacked as an oversheet, and a four-layered base material (total thickness 0.76 mm) is laminated by hot pressing or the like. In this case, the magnetic recording layer is made of the transparent P
By being provided in advance in the form of a tape or the entire surface on the surface of a VC sheet (oversheet), even when in the form of a tape, it is pressed into the base material 1 during lamination by hot pressing or the like,
It is integrated and laminated with a smooth surface. In addition, printing may be performed on a surface facing the outside of the core sheet, a surface facing the outside of the oversheet, or the like.

The light diffraction structure 4 comprises the light reflective layer 2 and the light diffraction structure layer 3. As a hologram which is a typical example of the light diffraction structure 4, both a plane hologram and a volume hologram can be used. Specific examples include a relief hologram, a Lippmann hologram, a Fresnel hologram,
Fraunhofer hologram, lensless Fourier transform hologram, laser reproduction hologram (image hologram, etc.), white light reproduction hologram (rainbow hologram, etc.), color hologram, computer hologram, hologram display, multiplex hologram, holographic stereogram, holographic diffraction grating And the like.

Materials for forming the light diffraction structure layer 3 include:
Thermoplastic resins such as polyvinyl chloride, acrylic resin (eg, PMMA), cellulose acetate, nitrocellulose, polystyrene, polycarbonate, unsaturated polyester,
Melamine, epoxy, polyester (meth) acrylate, urethane (meth) acrylate, epoxy (meth)
Use of thermosetting resins such as acrylate, polyether (meth) acrylate, polyol (meth) acrylate, melamine (meth) acrylate, and triazine acrylate alone, or a mixture of the above thermoplastic resins and thermosetting resins Further, a thermoformable substance having a radically polymerizable unsaturated group, or a material obtained by adding a radically polymerizable unsaturated monomer to the composition to obtain an ionizing radiation-curable material can be used. other than this,
Photosensitive materials such as silver salts, dichromated gelatin, thermoplastics, diazo photosensitive materials, photoresists, ferroelectrics, photochromic materials, thermochromic materials, and chalcogen glass can also be used.

The light diffractive structure (eg, hologram) can be formed in the light diffractive structure layer 3 using the above-mentioned materials by a conventionally known method. For example, when recording the interference fringes of a diffraction grating or hologram as a relief of surface irregularities, an original plate on which the diffraction gratings or interference fringes are recorded in the form of irregularities is used as a press mold, and a release layer and a protective layer are formed on a sheet. On the protective layer of the laminated sheet in which the layers are sequentially laminated, a coating solution in which the above materials are dissolved or dispersed is gravure coated,
Apply by roll coating, bar coating, etc.
By forming a coating film, stacking an original plate thereon, and applying heat and pressure to both by an appropriate means such as a heating roll, the concavo-convex pattern of the original plate can be duplicated. When a photopolymer is used, a photopolymer can be coated on the protective layer of the laminated sheet in the same manner, and then the original can be overlapped and irradiated with a laser beam to perform replication.

As described above, the method of recording the interference fringes of the diffraction grating or the hologram on the surface of the light diffraction structure layer 3 as the relief of the surface unevenness is particularly preferable because it has mass productivity and can reduce the cost. The thickness of such a light diffraction structure layer 3 is preferably in the range of 0.1 to 6 μm, and more preferably in the range of 0.1 to 4 μm.

When the interference fringes of a diffraction grating or a hologram are recorded on the surface of the light diffraction structure layer 3 as an uneven relief as described above, the light reflective layer 2 is placed on the relief surface in order to increase the diffraction efficiency. Preferably, it is formed. If a metal thin film of aluminum or the like that reflects light is formed on the relief surface as the light-reflective layer 2, a reflection type light diffraction structure, typically a reflection type hologram, is obtained, and a transparent thin film is formed on the relief surface. If formed, a transparent light diffraction structure, typically a transparent hologram, can be obtained. Whether to use the reflection type or the transparent type can be appropriately selected depending on the purpose. When a non-transparent metal thin film is used as the light-reflective layer 2, the light-reflective layer 2 is
However, in the case of a transparent light-reflective layer 2, the light-reflective layer 2 may be directed to any side. In short, the laminated structure in which the light-reflective layer 2 is laminated on the relief surface of the light-diffractive structure layer 3 may be arranged in such a direction that the light-diffractive structure (typically, a hologram) can be seen from the observation side. When printing is performed on the lower layer of the light diffraction structure layer, it is necessary to have transparency in order to secure the visibility, and it is preferable to use a transparent thin film. In this case, if the lower layer is made of a dark color such as a solid black, the visibility of the light diffraction structure such as a hologram is improved. Further, by selecting the material of the light-reflective layer and using it in combination, the light-reflective layer can be colored to an arbitrary hue.

When the light reflective layer 2 is formed of a metal thin film, Cr, Fe, Co, Ni, Cu, Ag, Au, G
e, Al, Mg, Sb, Pb, Cd, Bi, Sn, S
A metal such as e, In, Ga, or Rb, an oxide thereof, or a nitride thereof is formed alone or in combination. Of these, Al, Cr,
Ni, Ag, Au or the like is particularly preferable. When the light reflective layer 2 is formed of a metal thin film, a thin film forming method such as a vacuum evaporation method, a sputtering method, and an ion plating method is used.

As a material of the light reflecting layer 2, a continuous thin film of a substance having a different refractive index from that of the light diffraction structure layer 3 may be used.
The thickness of the continuous thin film may be any as long as it is a transparent region of the material forming the thin film, but is usually preferably 100 to 1000 °. Examples of a method for forming a continuous thin film on the relief surface include a thin film forming method such as a vacuum deposition method, a sputtering method, and an ion plating method. The continuous thin film may have a refractive index larger or smaller than that of the light diffraction structure layer, but the difference in the refractive index is preferably 0.3 or more, and the difference is 0.5 or more.
More preferably, it is 1.0 or more.

The continuous thin film having a higher refractive index than the light diffraction structure layer 3 includes ZnS, TiO ₂ , Al ₂ O ₃ , Sb ₂ S ₃
, SiO, TiO, SiO _{2 and the} like. As a continuous thin film having a lower refractive index than the light diffraction structure layer 3, Li
F, MgF ₂ , AlF _{3 and the} like. When the thickness is 200 ° or less, since the light transmittance is relatively small, it can be used as the light reflective layer 2 while being transparent. Further, a transparent synthetic resin having a different refractive index from the light diffraction structure layer 3, for example, a layer of polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl acetate, polyethylene, polypropylene, or polymethyl methacrylate is replaced with the light reflective layer 2. Can also be used.

The rewritable layer 5 is made of any one of three types of materials: (1) a leuco dye, (2) a polymer / organic low molecular dispersion, and (3) a liquid crystal.

(1) In the case of a leuco dye system, color development / decoloration is based on a combination of a leuco dye and an acidic compound, and a rewritable layer is formed by a composition in which these compounds are mixed with a polymer binder. There are competitive reaction systems using amphoteric compounds and phase separation systems using long-chain alkyl acidic compounds.

In the competitive reaction system, a phenolamine salt is used as an amphoteric compound, and the coloring reaction is carried out by a phenol group.
This utilizes the fact that the decoloration reaction proceeds by an amino group. Here, as the leuco dye, a triarylmethane-based compound (a crystal violet lactone in this range is well known), a diphenylmethane-based compound, a xanthene-based compound, a spiro-based compound, a fluoran-based compound, or the like is used. At this time, since the speed of the coloring reaction is faster than the speed of the decoloring reaction, the color is fixed in a colored state when heated and rapidly cooled, and is fixed in a decolored state when heated and gradually cooled. .

In the phase separation system, the compatible state and the incompatible state of the leuco dye and the long-chain alkyl acid compound are controlled by a difference in cooling rate. When the mixture is heated and gradually cooled in a compatible state, phase separation occurs, the mixture becomes incompatible, and the color is erased. Here, as the long-chain alkyl acidic compound, a phenol compound having a long-chain alkyl group or a phosphonic acid compound having a long-chain alkyl group can be used. The long-chain alkyl group preferably has 11 or more carbon atoms in the former case and 14 or more carbon atoms in the latter case.

In actual use, a thermal head is usually used for 1/100, rather than performing special cooling.
After instantaneously heating and heating in the order of 0 seconds,
By cooling at room temperature, "rapid cooling" can be realized, and the above system can be colored. In addition, as for `` cooling down '', if cooling after heating using a heating means having a large heat capacity such as a heat roller, a hot stamp, a heater bar, etc., `` cooling down '' is realized because a given amount of heat is large, Can be erased. In some cases, erasing with a thermal head is also possible by selecting the heating temperature and conditions. In the case of such a leuco rewritable material,
By appropriately selecting the type of leuco dye, black,
It can be colored in various colors such as blue and red.

(2) In the polymer / organic low-molecular dispersion system, a rewritable layer is formed by a composition in which a low-molecular organic material such as a fatty acid is uniformly dispersed in a transparent synthetic resin binder having a film-forming property. To form The layer is heated by a thermal head or the like to a temperature higher than the melting point of the low-molecular organic compound, and then cooled to a white turbid state.

As the binder for the synthetic resin, a resin which is transparent, has a film-forming property, and can uniformly disperse and hold a low-molecular organic substance is preferable. For example, polyvinyl chloride, vinyl chloride-vinyl acetate Examples include vinyl chloride resins such as copolymers, vinylidene chloride resins, acrylic resins, and other polyester resins. As the organic low molecular weight substance, various fatty acids and derivatives thereof can be used. Among them, saturated linear fatty acids having 1 carbon atom are preferable.
Those having a melting point in the range of 0 to 30 and a melting point of 30 to 160 ° C. are preferred, and one or two or more kinds can be used. The use of a low-molecular organic substance having a different melting point, for example, monocarboxylic acid and dicarboxylic acid has an advantage that the temperature range for the transparency can be widened.

(3) In the liquid crystal system, a smectic liquid crystal dispersed in a polymer matrix is used.
A polymer composite film is formed and used. In this liquid crystal system, the liquid crystal molecules are brought into a random alignment state or an alignment state by using heat and an electric field, and in these states, the properties of light scattering and light transmission are used, respectively. Further, a dichroic dye can be added for the purpose of improving the contrast and coloring, and a rewritable layer having excellent visibility can be obtained.

Any of the above (1) to (3) can be used according to the application. Among them, the leuco dye system of (1) and the liquid crystal system of (3) can perform color display, so that visibility is high. Is better in terms of

In order to efficiently stack the light diffraction structure 4 and the rewritable layer 5 on the information recording medium 10 or to use the product as a product without any trouble for a long period of time after the stacking, a material other than the light diffraction structure 4 and the rewritable layer 5 must be used. The following layer should be added to. First, an adhesive layer 7 may be interposed between the substrate 1 and the light diffraction structure 4 in order to facilitate adhesion between them. The rewritable layer 5 has a recording / reproducing function.
Since the erasing is performed, the protective layer 6 is preferably laminated in order to improve the durability of the surface, particularly, the abrasion resistance.

The material forming the adhesive layer 7 is preferably a material having good adhesiveness to the light diffraction structure 4 and capable of firmly bonding to the substrate 1. Specifically, vinyl chloride resins, vinyl acetate resins, vinyl chloride-vinyl acetate copolymer resins, acrylic resins, polyester resins, polyurethane resins, polyamide resins, rubber modified products, and the like. Suitable ones can be selected from among them, and these can be used alone or in a mixed system of two or more kinds, and can be used by further adding a hard resin, a plasticizer, and other additives as necessary. it can.

The protective layer 6 protects the exposed surface of the rewritable layer, and is preferably made of a resin having transparency, abrasion resistance, abrasion resistance, heat resistance, chemical resistance, stain resistance and the like. I have. As a resin forming the protective layer 6, in addition to a thermoplastic resin such as an acrylic resin, a polyurethane resin,
A thermosetting resin such as an epoxy resin and a melamine resin, and further, an ionizing radiation-curable resin can be used. Specific examples of the ionizing radiation-curable resin include polyurethane acrylate, polyester acrylate, epoxy acrylate, polyether acrylate, and the like. These are polyfunctional or polyfunctional in order to adjust the viscosity or crosslink density of each prepolymer. A monofunctional monomer may be added and used, and if necessary, a known photoreaction initiator and sensitizer may be added and used. In addition, polyene / thiol-based ionizing radiation-curable resins and the like also have excellent abrasion resistance and can be preferably used.

If necessary, additives such as a surfactant, an antistatic agent, and an ultraviolet absorber may be added to the resin for forming the protective layer 6. Also, a small amount of wax or the like may be added in order to secure the slipperiness of the surface. The protective layer 6 is formed by adding a diluent or a solvent to the resin for forming the protective layer and mixing or dispersing the diluent or solvent to prepare a coating liquid for forming the protective layer. After applying by the method, UV (ultraviolet) irradiation or E
The protective layer can be formed by curing the resin by B (electron beam) irradiation or the like. When an organic solvent is added to the coating solution, it is preferable that after application, first, hot-air drying is performed to remove the organic solvent, and then the resin is cured by irradiation with UV or EB.

The thickness of the protective layer 6 is preferably in the range of 0.5 to 4.0 μm. The thickness of the protective layer is 0.5 μm
If less, sufficient scratch resistance and abrasion resistance cannot be obtained,
Further, a thickness exceeding 4.0 μm is not necessary because the wear resistance is already sufficient.

Since the information recording medium 10 of the present invention is obtained by laminating each layer as described above, it can be manufactured by sequentially laminating each layer on the base material 2. It is preferable to prepare and transfer a transfer sheet 20 on which each layer other than the base material 10 is formed as a transfer layer of the sheet.

FIG. 3 shows the actual structure of the transfer sheet 20. A peelable layer 8, a protective layer 6, a rewritable layer 5, a light diffraction structure layer 3, and a light reflection layer are formed on a sheet-like substrate 21. The light diffractive structure 4 made of 2 and the adhesive layer 7 are sequentially laminated. However, as a minimum constituent element as the transfer sheet, a light diffraction structure including a rewritable layer, a light diffraction structure layer 3 and a light reflection layer 2 is laminated on a peelable sheet having a peelable upper surface. Since it suffices if necessary, the peelable layer 8, the protective layer 6, and the adhesive layer 7 may be added as needed. If the protective layer has releasability from the sheet-like base material, it is used as a releasable protective layer, and the protective layer has the function of the releasable layer without providing the releasable layer. You can also.

Sheet-like substrate 21 in transfer sheet 20
It is preferable to use a material which has mechanical strength, is hardly stretched by heating, and is smooth. Usually, a polyethylene terephthalate (= PET) resin film is often used, but other resin films, metal foils, and paper may be used. At the time of transfer, it is preferable to form the releasable layer 8 so that each layer can be smoothly separated from the transfer sheet 20. However, depending on the sheet-like base material 21 and the material of the transfer layer,
In some cases, the peelable layer 8 is unnecessary.

The adhesive layer 7 need not be provided on the transfer sheet 20 depending on how the transfer sheet 20 is used. For example, it is unnecessary when the substrate 1 to be transferred and the outermost layer of the transfer layer have thermal adhesiveness to each other, or
This is because the transfer can be performed while applying an adhesive to one or both of the substrate 1 and the light diffraction structure 4 which is the outermost layer of the transfer layer. However, since it is troublesome to prepare and apply the adhesive every time the transfer is performed, it is better to form an adhesive layer on the transfer sheet 20.

The peelable layer 8 is made of a paint for forming a peelable layer prepared by adding a wax or silicone or the like to a solvent solution of a suitable binder resin such as an acrylic resin or a cellulose acetate resin, and by an appropriate means. It can be obtained by coating on the sheet-like base material 21 and drying.

Each of the subsequent layers is formed, for example, on the sheet-like substrate 21 or on a peelable sheet to which the release layer 8 is adhered, for example, the light diffraction structure layer 3, the light reflective layer 2, the rewritable layer 5, and the necessary layers. The paint or ink necessary for forming the adhesive layer 6 is sequentially applied and formed according to the conditions described above, and if necessary, heat drying, irradiation with ionizing radiation, and the like are performed, and the layers are cured and cured. . However, the light diffraction structure layer 3 is provided with irregularities using a mold after coating. The light-reflective layer 2 may be formed by vacuum evaporation,
Lamination is performed by a method such as sputtering.

When transferring to the base material 1 using the transfer sheet 20, the transfer sheet 20 is arranged on the base material 1 so that each layer to be transferred faces the base material 1 side.
The transfer may be performed by applying heat and pressure from the back surface of the transfer sheet 20, and then peeling off the sheet-like base material 21 of the transfer sheet 20. Thereafter, if necessary, when the heating press is performed again, the transferred layers are partially embedded in the base material 1 so that the transferred portions and the surrounding portions form the same plane.

Although not described in the above description of the information recording medium 10 and the transfer sheet 20, in each case, a corona treatment or a chemical treatment may be performed to improve or stabilize the adhesiveness between the respective layers. May be provided with a primer layer. The information recording medium 1 of the present invention basically has the above configuration, and is preferably manufactured using a transfer sheet. However, the information recording medium 1 may include other information recording means and the like.

Taking an example of a card, as a character and a pattern,
(1) The name of the card issuer, the name of the card, or the name of the association if it is to be distributed to the member, such as the tint block, the character, and (2) the arrow to indicate the direction of insertion of the card into the reader / writer. Mark, and (3) general precautionary notes on use may be formed on the front surface or the back surface. Known information recording means include (4) a magnetic recording layer,
(5) an IC module, (6) a writable layer made of a writable material for the card holder to sign, (7)
An optical recording layer recordable by a laser beam, (8) an image formed by sublimation transfer or photo pasting, or an area where these can be formed. Depending on the use of the information recording medium, other information recording means may be provided.

The information recording medium 10 of the present invention can be used, for example, as a magnetic card, a contact-type or non-contact-compatible IC card, an optical card (= optically recordable card), or an arbitrary composite card thereof. It can be used for pass tickets, boarding tickets, boarding passes, prepaid cards, admission tickets, play tickets, point cards, cash cards, credit cards, ID cards, employee ID cards, membership cards, etc. Widely available.

[0047]

EXAMPLES (Example 1) First, a transfer sheet was prepared as follows. Using a 25 μm-thick polyethylene terephthalate (= PET) resin film as a sheet-like substrate, a 1 μm-thick releasable protective layer was formed by a gravure coating method using a composition for forming a releasable protective layer having the following composition. Further, using a composition for forming a reversible recording layer having the following composition on the releasable protective layer, also by the gravure coating method,
A reversible recording layer having a thickness of 1 μm was formed. (Composition for forming a releasable protective layer) ・ Cellulose acetate resin 5 parts by mass ・ Methanol 25 parts by mass ・ Methylethyl ketone 45 parts by mass ・ Toluene 25 parts by mass ・ Methylolated melamine resin 0.5 parts by mass ・ paratoluene Sulfonic acid 0.05 parts by mass (composition for forming a reversible recording layer) ・ 15 parts by mass of vinyl chloride / vinyl acetate copolymer resin ・ 5 parts by mass of behenic acid ・ 80 parts by mass of tetrahydrofuran

On the formed reversible recording layer, a hologram layer forming composition having the following composition was applied by a gravure coating method to form a 2 μm thick hologram forming resin film. (Hologram layer forming composition) ・ Acrylic resin 40 parts by mass ・ Melamine resin 10 parts by mass ・ Cyclohexanone 50 parts by mass ・ Methyl ethyl ketone 50 parts by mass ・ Aryl alkyl ketone 3 parts by mass

The hologram-forming resin film was embossed using a metal plate on which hologram interference fringes were formed in a concavo-convex shape to give the hologram concavities and convexities, thereby forming a hologram layer. Thereafter, aluminum was vapor-deposited on the resin surface having the irregularities to a thickness of 300 ° to form a light-reflective layer. Finally, a composition for forming a heat seal layer having the following composition was applied to the aluminum-deposited surface by a gravure coating method to form a heat seal layer having a thickness of 2 μm. (Composition for forming heat seal layer)-20 parts by mass of vinyl chloride / vinyl acetate copolymer resin-10 parts by mass of acrylic resin-20 parts by mass of ethyl acetate-50 parts by mass of toluene

As described above, a transfer sheet having the structure of PET film / peelable protective layer / reversible recording layer / hologram layer / light reflective layer / heat seal layer was obtained. Note that the symbol “/” means that components before and after this symbol are stacked on each other.

The following materials were prepared as transfer objects when transferring using the above transfer sheet. Two sheets of white vinyl chloride resin sheet (= core sheet) having a thickness of 280 μm are stacked, and a transparent vinyl chloride resin sheet (= over sheet) having a thickness of 100 μm is stacked on and under each of them,
A total of four sheets were temporarily pasted to prepare a card base material having a thickness of 760 μm, and the transfer sheet obtained above was coated on one surface with the heat seal layer side facing the card base material. Using a transfer mold having a size of 5 cm × 2 cm, transfer was performed under the conditions of mold temperature: 140 ° C., pressure: 20 kg / cm ² , and after transfer, only the PET film was peeled off.

In order to improve the adhesive strength between the respective sheets of the above temporarily attached card base material, and to provide a peelable protective layer / reversible recording layer / hologram layer / light reflection transferred onto the card base material. Temperature: 120 ° C., pressure: 2 in order to embed the laminate comprising each layer of the heat-resistant layer / heat-sealable layer in the card base material.
As a result of hot pressing under the condition of 0 Kg / cm ^2, a card was obtained in which the surface of the peelable protective layer was flush with the surrounding card base material.

With respect to the reversible recording layer of the obtained card,
When printing was performed under the condition of 0.5 mJ / dot, the recorded state was good and the printed information was easily read. In this state, the hologram of the background could be visually recognized from the portion other than the color developed by printing. When the printed information was erased under the condition of 0.2 mJ / dot, it was completely erased, and there was no problem in the visibility of the lower layer hologram in the erased state.

Example 2 A transfer sheet was prepared in the same manner as in Example 1 except that the light-reflective layer on the transfer sheet in Example 1 was formed by evaporating TiO ₂ to a thickness of 300 °. . Hereinafter, in the same manner as in Example 1, transfer was performed on a card base material, and evaluation was performed. The difference was that the light-reflective layer was transparent, so that the base could be seen through.
Otherwise, the same results as in Example 1 were obtained.

[0055]

According to the first aspect of the present invention, since the rewritable layer is located on the upper layer, the rewritable layer has better recording visibility than the conventional case where the rewritable layer is located on the lower layer. It is possible to provide an information recording medium having an advantage that damage and contamination are less as compared with a case where the resulting light diffraction structure is conventionally exposed on the surface. According to the invention of claim 2, in addition to the effect of the invention of claim 1, since an adhesive layer is interposed between the base material and the light diffraction structure, each of them does not have heat fusion property. Also, it is possible to provide an information recording medium in which mutual adhesion is ensured. According to the third aspect of the present invention, in addition to the effects of the first or second aspect, the protective layer is laminated on the rewritable layer. And an information recording medium which is hardly damaged. According to the invention of claim 4, by laminating the rewritable layer and the optical diffraction structure on the peelable sheet, an information recording medium in which a light diffraction structure is laminated on a lower layer and a rewritable layer is laminated on an upper layer on an appropriate base material Can be provided. According to the invention of claim 5, in addition to the effect of the invention of claim 4, the release sheet has a structure in which a release layer is laminated on a sheet-like base material. Can be provided. According to the invention of claim 6, in addition to the effect of the invention of claim 4 or 5, the adhesive layer is laminated on the surface of the transfer layer facing the object to be transferred. It is possible to provide a transfer sheet capable of transferring by adhesiveness with an agent.
According to the seventh aspect of the present invention, in addition to the effects of any one of the fourth to sixth aspects of the present invention, since the protective layer which is the uppermost layer after the transfer is provided, the information recording having excellent surface properties by the transfer. A transfer sheet from which a medium can be obtained can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of an information recording medium according to an embodiment of the present invention.

FIG. 2 is a sectional view of an information recording medium according to another embodiment of the present invention.

FIG. 3 is a sectional view of a transfer sheet.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Light reflective layer 3 Light diffraction structure layer 4 Light diffraction structure 5 Rewritable layer 6 Protective layer 7 Adhesive layer 8 Peelable layer 10 Information recording medium 20 Transfer sheet

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02B 5/18 B41M 5/18 B 5B035 5/32 F G06K 19/06 E 101A 5/26 102 G06K 19 / 00 DE (72) Inventor Masayuki Ishikawa 1-1-1 Ichigaya-Kaga-cho, Shinjuku-ku, Tokyo F-term in Dai Nippon Printing Co., Ltd. (reference) 2C005 HB01 HB04 HB07 HB09 HB13 HB14 JA01 JA11 JA18 JA19 JA26 JB19 KA15 KA25 KA37 KA41 KA48 LA03 LA11 LA19 LA30 2H026 AA07 AA09 BB02 BB24 EE05 FF01 FF11 FF13 FF29 GG01 GG10 2H049 AA03 AA07 AA25 AA60 AA64 CA05 CA09 CA10 CA15 CA22 2H111 HA07 HA23 HA35 3B005 EA01 EB01 FB01 EB01 FB01

Claims (7)

[Claims] 1. A light diffraction structure comprising at least a light reflective layer and a light diffraction structure layer laminated on a substrate, and a rewritable layer is laminated on the light diffraction structure. Information recording medium. 2. The information recording medium according to claim 1, wherein an adhesive layer is interposed between the substrate and the light diffraction structure. 3. The information recording medium according to claim 1, wherein a protective layer is laminated on the rewritable layer. 4. A releasable surface of a releasable sheet having a releasable surface on one side, wherein a rewritable layer and a transfer layer comprising a light diffraction structure layer and a light reflective layer are laminated. Transfer sheet. 5. The transfer sheet according to claim 4, wherein the releasable sheet is formed by laminating a releasable layer on one surface of a sheet-like substrate. 6. An adhesive layer is laminated on the transfer layer on the exposed surface side of the light reflective layer.
Or the transfer sheet according to 5. 7. The transfer sheet according to claim 4, wherein a protective layer is laminated on the transfer layer on the side of the peelable layer.