JP3508266B2 - Reversible thermosensitive recording medium - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hologram design having a hologram image on a reversible thermosensitive recording layer which is rewritable depending on temperature and can be used as an information medium, a seal or a label, a transfer material and the like. The present invention relates to a reversible thermosensitive recording medium having excellent properties and anti-counterfeiting property.

[0002]

2. Description of the Related Art Conventionally, rewritable thermosensitive recording media have been disclosed in JP-A-55-154198 and US Pat.
No. 268413, a thermoplastic resin such as polyvinyl chloride and a thermosensitive recording layer mainly composed of an organic low molecular weight substance such as a higher fatty acid dispersed in the thermoplastic resin are provided on a support. There is something.

This heat-sensitive recording layer has a light absorption property (light scattering property) that reversibly changes depending on temperature.
That is, the heat-sensitive recording material constituting the heat-sensitive recording layer has two state transition temperatures T at temperatures higher than the specific temperature T ₀ near room temperature.
₁ and T ₂ (where T ₁ <T ₂ ) and the thermal recording layer is T
_When heated to ₂ or more and held and then cooled to T ₀ or less, the thermosensitive recording material becomes clouded, light scattering increases, and the maximum light shielding state is obtained. On the other hand, when the heat-sensitive recording layer in the cloudy state is heated to T ₁ or more and less than T ₂ , held, and then cooled to T ₀ or less, its light scattering property is reduced and becomes a transparent state. Therefore, under the temperature condition of T ₀ or less, the maximum light-shielding state and the transparent state of the thermosensitive recording layer can be stably maintained, respectively, and these states can be reversibly changed. By setting the state, the visible information recorded can be used in a rewritable state and can be used as a heat-sensitive recording medium due to the difference from the other state.

Further, only by controlling the thermal energy,
Reversible thermosensitive recording materials that chemically develop and decolor are disclosed in JP-A-2-188293, JP-A-2-188294, International Publication No. WO90 / 11898, and the like, which are referred to as leuco compounds. A reversible heat-sensitive recording material mainly composed of a binder and a color-developing / reducing agent that develops / decolorizes a leuco compound by controlling heat energy, and is provided on a support as a heat-sensitive recording layer. . This heat-sensitive recording material uses a compound having both properties of a group having a color-developing effect (acidic component) and a group having a color-reducing effect (component made of a base) as a color-developing and color-reducing agent to develop color by controlling applied heat It erases color. With this heat-sensitive recording material, it is possible to hold a stable image with time in an environment of daily life. The color developing and decoloring characteristics and the image stability are largely due to the chemical structure of the developer and decolorizer in the material.

Further, in recent years, a relief hologram is formed on a base material of a medium such as a card by using a seal, a label, a transfer foil or the like for the purpose of decoration and prevention of counterfeiting. In particular, the transfer foil is widely used as a hologram forming means because it is inexpensive, thin, and difficult to tamper with. Such a hologram transfer foil is disclosed in JP-A-61-19.
As described in Japanese Patent Publication No. 037037, a support varnish layer, a resin layer having a surface relief hologram formed thereon, a metal reflection layer, and a heat-sensitive adhesive layer are sequentially formed on one surface of a support film, The heat-sensitive adhesive layer is brought into close contact, and the transfer portion is heated and pressed to transfer and form a predetermined hologram image. When there is a printed pattern on the base material, by using a transparent hologram that uses a transparent metal reflective layer,
It is possible to superimpose the hologram image and the printed pattern on each other without affecting the appearance of the printed pattern on the substrate due to the hologram. Furthermore, a print-integrated hologram in which a hologram image and a print pattern are superposed has been proposed and is used as a seal, a label, a transfer foil, or the like.

[0006]

However, the hologram as described above is forged or counterfeited simply due to the peculiarity of the stereoscopic image of the hologram and the difficulty of the hologram transfer foil manufacturing process.
Although it is a measure to prevent illegality such as alteration and falsification, forgery technology that prints a regular hologram image pattern with transparent ink on metal foil and makes it look like a hologram image at first glance has appeared There are some aspects that cannot be said to be fraud prevention measures that can be identified at first glance. In addition, security information such as fraud prevention measures for cards etc.
For identification, it is concentrated on a specific part of the card, or arranged on the card as an information form that cannot be easily identified by visual inspection, etc., but there are still no measures against fraud by combining with a hologram, At present, the hologram portion of the card as described above only provides information of the hologram.

Therefore, according to the present invention, by forming a rewritable reversible thermosensitive recording layer under a hologram stereoscopic image so that visible information can be rewritten and displayed, it is difficult to forge the medium itself and it is possible to judge whether the medium is true or false. An object of the present invention is to provide a reversible thermosensitive recording medium which can be easily carried out.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and the invention according to claim 1 absorbs a reflective thin film layer and infrared rays on a substrate to generate heat. Photothermal conversion layer containing infrared absorbing material, rewritable reversible thermosensitive recording layer, and holographic material having fine irregularities
The refractive index on the surface of the film forming layer and the surface of the fine irregularities is
A reversible thermosensitive recording medium comprising a hologram layer formed of a transparent thin film layer different from a ram forming layer .

According to a second aspect of the invention, a release layer and a fine layer are provided on the support.
Hologram forming layer having small uneven shape and minute unevenness thereof
The shape surface has a different refractive index from the hologram forming layer
A hologram layer comprising a thin film layer , a rewritable reversible thermosensitive recording layer, a photothermal conversion layer containing an infrared absorbing material which absorbs infrared rays and generates heat, a reflective thin film layer, and an adhesive layer. It is a reversible thermosensitive recording medium.

[0010]

According to a third aspect of the present invention, in the reversible thermosensitive recording medium according to the first or second aspect, the reversible thermosensitive recording layer comprises:
A reversible thermosensitive recording medium comprising a resin base material and an organic low molecular weight substance dispersed in the resin base material as a main component, and the transparency thereof reversibly changes depending on temperature.

The invention of claim 4 is the reversible thermosensitive recording medium according to claim 1 or 2, wherein the reversible thermosensitive recording layer comprises:
A leuco compound, a color-developing and reducing agent that thermally reacts with the leuco compound to develop or reduce color, and a binder as main components,
Further, the reversible thermosensitive recording medium is characterized in that it reversibly develops and erases colors by controlling heat energy.

A fifth aspect of the present invention is the reversible thermosensitive recording medium according to the first aspect, characterized in that an adhesive layer is provided on the surface in contact with the adherend.

[0014]

In the reversible thermosensitive recording medium of the present invention, visible rewritable visible information is present in the hologram image from the upper surface, and the reversible reversible thermosensitive recording layer below the hologram image is in contact with the infrared wavelength region. By providing a photothermal conversion layer that absorbs light and converts it into heat, visible information can be written using a non-contact printing means such as laser light, and the hologram image and the rewritable visible information are formed in a superimposed state. Therefore, it is possible to distinguish the illegal acts such as forgery and falsification while showing the decorativeness.

[0015]

The present invention will be described in detail below with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of the reversible thermosensitive recording medium of the present invention, and FIG. 2 is a sectional view of a reversible thermosensitive recording medium of the second invention of the present invention.

FIG. 1 shows a layer structure of a reversible thermosensitive recording medium 1 of the present invention, which comprises a substrate 2 and a reflective thin film layer 3 and a photothermal conversion containing an infrared absorbing material which absorbs infrared rays and generates heat. A layer 4, a rewritable reversible thermosensitive recording layer 5, a hologram forming layer 6 having a hologram image, and a hologram layer 8 including a transparent thin film layer 7 having a refractive index different from that of the hologram forming layer 6 are sequentially provided. Further, depending on the application of the reversible thermosensitive recording medium 1, for example, in the case of a card-shaped information medium, information such as a printing layer or a magnetic recording layer formed of character information or a design is formed on the other surface of the base material 2. An optional recording means may be provided, and when it is used as a seal or a label, an adhesive layer (not shown) made of a heat-sensitive adhesive or a pressure-sensitive adhesive (adhesive) can be provided on the other surface of the substrate 2. .

As the hologram image used for the hologram layer 8, an image according to a conventionally known hologram technique can be used. For example, as a hologram, these images are formed on the hologram forming layer 6 as a white light reproducing hologram composed of a relief hologram, a monochromatic light reproducing hologram including a Fresnel type or a Fourier transform type, and the hologram forming layer is formed on the relief forming surface. Has a refractive index different from 6,
Moreover, a high hologram effect can be obtained by providing the reflective thin film layer 6 having transparency. The hologram may be a diffraction grating having specific information in addition to images such as characters and images. The diffraction grating changes the spatial frequency, the direction of the diffraction grating, or a combination thereof to record information. Further, the hologram layer 8 can be a volume hologram such as a Lippmann hologram, and can be arbitrarily selected according to the application. Further, the hologram image of the hologram layer 8 may not be provided on the entire surface, the hologram image may be formed on a part of the medium, and the hologram layer 8 itself may be partially reversible depending on the size of the hologram image. It can also be provided on the thermal recording layer 5. The base material 2 may be omitted and the hologram layer 8 may be used as a support. According to this, the layer thickness can be reduced, and it is suitable for a seal or a label.

The layers constituting the layer will be described below. Base material 2
Has a role as a support, for example, paper, synthetic paper, polyvinyl chloride, polyethylene terephthalate (P
ET), etc., which are conventionally used for cards such as prepaid cards, cash cards, credit cards, entrance tickets, pass tickets, gift certificates, certificates, stickers, labels, etc., and are not particularly limited, You may combine the thing of different materials. Further, it may have a single-layer structure or a multi-layer structure, or may be appropriately selected depending on the application such as transparent, semi-transparent and opaque. The reflective thin film layer 3 may be omitted if the reversible thermosensitive recording layer and the hologram layer are colored so that the visibility of the hologram layer is improved. For example, there is a base material having reflectivity in the case of a rainbow hologram and a dark-colored base material (black as an example) in the case of a Lippmann hologram. Further, if the substrate is transparent to infrared rays, it is possible to record on the reversible thermosensitive recording layer by irradiating the photothermal conversion layer from the substrate side with infrared rays.

The reflective thin film layer 3 is provided mainly for obtaining the visibility of the reversible reversible thermosensitive recording layer 5,
In the case of a cloudy color-transparent reversible reversible thermosensitive recording layer, a thin film-like reflective layer made of a metal material having light reflectivity is preferable. For example, aluminum, tin, silver, copper, magnesium,
There are chromium, nickel, etc., and their alloys or compounds.
As a means for forming these into a thin film, known methods such as a vacuum vapor deposition method, a reactive vacuum vapor deposition method, a sputtering method, a reactive sputtering method, an ion plating method and an electroplating method can be used. This reflective thin film layer 3
Can be omitted depending on the characteristics of the base material 2.

The photothermal conversion layer 4 absorbs light having a wavelength in the infrared region to generate heat, and has an absorption wavelength range of 700.
It is preferably in the range of ˜1000 nm. In this embodiment, it is formed by applying an infrared absorbent as a main component, which is dispersed in a binder or the like. Specific examples of infrared absorbers include polymethine dyes; pyrylium, thiopyrylium compounds; squarylium compounds; croconium compounds; azulenium compounds; phthalocyanine compounds; tetradehydrocholine compounds; dithiol metal complex salts compounds; naphthoquinone, anthraquinone compounds; triphenylmethane compounds. Aminium, diimmonium, etc. may be mentioned. Further, as a binder for dispersing the infrared absorber, an acrylic resin,
Polyester resin, vinyl chloride resin, vinyl chloride resin and vinyl acetate resin, copolymer resin of vinyl alcohol, maleic acid, etc., polyurethane, epoxy acrylate,
An ultraviolet curing resin such as an acrylic oligomer is used alone or in combination of two or more. For these coating methods, known gravure coating, lip coating, comma coating, die coating, micro gravure coating, curtain coating, roll coating, and other coating means, gravure printing, offset printing, silk printing, flexo printing, and other printing means are used. The layer thickness is about 0.1 to 10 μm.
Alternatively, it may be formed in a film thickness of 50 to 1000Å by vapor deposition or sputtering without using a binder.
In addition, it is desirable that each layer laminated on the photothermal conversion layer 4 has high infrared transmittance. In addition, the photothermal conversion layer 4
May be provided on the upper side (infrared irradiation side) of the rewritable reversible thermosensitive recording layer 5 as long as it has optical transparency.

Rewritable reversible thermosensitive recording layer 5
Is that the transparency changes reversibly depending on the temperature,
The visible information is recorded by partially changing the information.
For example, as described above, the main component is the resin base material and the organic low molecular weight substance dispersed therein, and the heat-sensitive recording material has two state transition temperatures T ₁ and T _{2 at a} temperature higher than the specific temperature T ₀ near room temperature. (Provided that T ₁ <T ₂ ), and when the reversible thermosensitive recording layer is heated to T ₂ or higher, and held and then cooled to T ₀ or lower, the thermosensitive recording material becomes clouded to increase the light scattering property. And the maximum light blocking state is reached. On the other hand, when the reversible thermosensitive recording layer in the white turbid state is heated to T ₁ or more and less than T ₂ and held, and then cooled to T ₀ or less, its light scattering property is reduced and becomes a transparent state. As described above, under the temperature condition of T ₀ or less, the maximum light-shielding state and the transparent state of the reversible thermosensitive recording layer can be stably maintained, respectively, and these states can be reversibly changed. By setting the state of 1 to the base state, the visible information recorded can be held in a rewritable state due to the difference from the other state.

The above resin base material has a refractive index similar to that of organic low molecules, is incompatible, has excellent mechanical strength, has film forming ability, and has excellent transparency, and is a thermosetting resin or thermoplastic resin. Is used. Specific examples include polyester resins such as saturated copolymerized polyesters; polyvinyl chloride resins; vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinyl acetate-vinyl alcohol copolymers, vinyl chloride-acrylate copolymers, and other vinyl chlorides. Copolymers; Polyurethane resins; Polycarbonate resins; Polyvinylidene chloride resins; Vinylidene chloride-vinyl chloride copolymers, vinylidene chloride copolymers such as vinylidene chloride-acrylonitrile copolymers; Rubber systems such as natural rubber and synthetic rubber; Polyamides There are resins; silicone resins; polyacrylate or polymethacrylate resins, or copolymers thereof; polyethylene resins and the like, and these are used alone or as a mixture of two or more thereof.

The organic low molecule dispersed in the resin base material includes a fatty acid or a fatty acid derivative or an alicyclic organic acid. More specifically, a saturated or unsaturated mono- or dicarboxylic acid, or an ester thereof, Some include amides. Specific examples of fatty acids include undecanoic acid, lauric acid, myristic acid, pentadecanoic acid,
Palmitic acid, heptadecanoic acid, stearic acid, nanodecanoic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, montanic acid, melissic acid, adipic acid, pimelic acid, speric acid, azelaic acid, sebacic acid, 1,9
-Nonamelenylene dicarboxylic acid, 1,10-cyclobutanedicarboxylic acid, 1,2-cyclopentanedicarboxylic acid,
1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid and the like can be mentioned. Incidentally, the coating liquid obtained by mixing the organic low molecule and the resin base material in the same manner, known gravure coating,
The reversible thermosensitive recording layer 5 is formed using a coating means such as a lip coat, a comma coat, a die coat, a micro gravure coat, a curtain coat and a roll coat, and a printing means such as a gravure printing, an offset printing, a silk printing and a flexo printing. The rewritable reversible thermosensitive recording layer 5 preferably has a layer thickness of about 1 to 50 μm.

Further, the rewritable reversible thermosensitive recording layer 5
As another heat-sensitive recording material used in the above, a reversible heat-sensitive recording material containing a leuco compound, a color-developing / color-reducing agent for developing / decoloring the leuco compound by controlling heat energy, and a binder as main components can be used. Examples of the leuco compound include fluorene compounds, fluorane compounds, phthalide derivatives and the like. Specific examples include crystal violet lactone, 3-indolino-3-p-dimethylaminophenyl-6-dimethylaminophthalide, 3
-Diethylamino-7-chlorofluorane, 2- (2-
Fluorophenylamino) -6-diethylaminofluorane, 2- (2-fluorophenylamino) -6-di-
n-Butylaminofluorane, 3-diethylamino-7
-Cyclohexylaminofluorane, 3-diethylamino-5-methyl-7-t-butylfluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3
-Diethylamino-6-methyl-7-p-butylanilinofluorane, 3-cyclohexylamino-6-chlorofluorane, 2-anilino-3-methyl-6- (N-ethyl-p-toluidino) -fluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 3-pyrrolidino-7-cyclohexylaminofluorane, 3-N-methylcyclohexylamino-6-methyl-7-anilinofluorane, 3-N-ethyl Mention may be made of pentylamino-6-methyl-7-anilinofluorane and the like.

The amphoteric compound acting as a color-developing agent for the leuco compound has at least one of a phenolic hydroxyl group and a carboxyl group, and has an amino group as a functional group or as a part of a salt compound. is there. As a color-developing agent, for example, a compound having both an acidic component consisting of a phenolic hydroxyl group or a carboxyl group and a basic group consisting of an amino group, which becomes acidic or basic due to the difference in thermal energy and develops a leuco compound (coloring). ) ・ Some have color reduction (erasing). The basic group may be present as a functional group or as a part of chloride. Examples of the developer / color-reducing agent having an amino group as a functional group include aminobenzoic acid, hydroxyaminobenzoic acid, aminophenols, aminonaphthoic acids, nicotinic acids and the like. Specific examples include p-aminobenzoic acid, m-aminobenzoic acid, o-aminobenzoic acid,
4-amino-3-methylbenzoic acid, 3-amino-4-methylbenzoic acid, 2-amino-5-ethylbenzoic acid, 3-
Amino-4-butylbenzoic acid, 4-amino-3-methoxybenzoic acid, 3-amino-4-ethoxybenzoic acid, 2-
Amino-5-chlorobenzoic acid, 4-amino-3-bromobenzoic acid, 2-amino-4-nitrobenzoic acid, 4-amino-3-nitrobenzoic acid, 3-amino-4-nitrilebenzoic acid, aminosalicylic acid , Diaminobenzoic acid, 2-methyl-5-aminonaphthoic acid, 3-ethyl-4-aminonaphthoic acid, nicotinic acid, isonicotinic acid, 2-methylnicotinic acid, 6-chloronicotinic acid and the like.

The compound having a basic group as a part of chloride is a salt or complex salt of a compound having a phenolic hydroxyl group or a carboxyl group and a compound having an amino group, for example, hydroxybenzoic acids and hydroxysalicylic acid. Examples thereof include salts or complex salts of acids such as gallic acids, gallic acids, and bisphenolacetic acid with aliphatic amines, phenylalkylamines, trialkylamines, and the like. As specific examples, p-hydroxybenzoic acid-alkylamine salt, p-hydroxybenzoic acid-phenylalkylamine salt, m-hydroxybenzoic acid-alkylamine salt, 2,
4-dihydroxybenzoic acid-alkylamine salt, 4,5
-Dihydroxybenzoic acid-tolylalkylamine salt, p
-Hydroxybenzoic acid methyl-alkylamine salt, p-
Hydroxybenzoic acid stearyl-alkylamine salt, gallic acid-alkylamine salt, gallic acid dodecyl-alkylamine salt, gallic acid stearyl-alkylamine salt,
Examples thereof include bisphenolacetic acid-alkylamine salt, bisphenolacetic acid stearyl-alkylamine salt, and bisphenolacetic acid octyl-alkylamine salt.

Further, these developer / color-reducing agents are disclosed in Japanese Patent Application Laid-Open No. 2-188293 and Japanese Patent Application Laid-Open No.
No. 188294, International Public Law No. WO90 / 118
Materials described in No. 98 and the like can also be mentioned. Also, two or more kinds may be used at the same time.

As the binder, a polymer resin soluble in water or an organic solvent can be used.
Specific examples of such polymer resins include polyvinyl alcohol, methyl cellulose, cellulose acetate, methoxy cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, polyvinyl pyrrolidone, gelatin, casein, starches, sodium polyacrylate, and styrene-maleic acid copolymer. Water-soluble polymer such as polymer, polystyrene, polyvinyl chloride, linear saturated polyester, homo- or copolymer of methacrylic resin such as polymethylmethacrylate or polyethylmethacrylate, polyurethane, polybutyral, nitrocellulose, ethylcellulose , Epoxy resin, acrylic resin, polyester,
Solvent-soluble polymers such as paraffin wax, polyethylene wax, carnauba wax, microcrystalline wax, stearic acid amide, and rubbers can be used. The above leuco compound, the binder is dissolved in a coating liquid obtained by uniformly dispersing or dissolving the amphoteric compound in water or an organic solvent, and if necessary, a liquidity improving agent such as a dispersant, a defoaming agent, and a thickener. The coating liquid added is bar coat, blade coat, air knife coat, gravure coat,
The thermosensitive recording layer 4 is formed by coating and drying by a known coating method such as roll coating. The rewritable thermosensitive recording layer 4 preferably has a layer thickness of about 1 to 50 μm.

Further, the hologram layer 8 comprises a hologram forming layer 6 and a transparent thin film layer 7. The hologram forming layer 6 has a hologram image formed on at least a part thereof. In the case of a relief hologram, a relief forming surface (unevenness) representing a hologram image is formed on a resin, and as a resin material, a thermoplastic resin such as polyvinyl chloride, acrylic, polystyrene, or polycarbonate, unsaturated polyester, melamine, Uses thermosetting resins such as epoxy, polyester (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, polyether (meth) acrylate, polyol (meth) acrylate, melamine (meth) acrylate, and triazine acrylate. It is possible to use a mixture of these, or a mixture thereof. When the relief forming surface is exposed to the outside, a protective layer (not shown) may be provided on the upper surface of the relief forming surface to protect the relief forming surface.

In the present invention, the materials shown in Table 1 are used, and a thin film layer having a refractive index different from that of the hologram layer and exhibiting transparency is provided on the relief forming surface. A higher hologram effect can be obtained because the reflected light at the interface between the thin film layer and the hologram layer and the reflection occurring at the interface between the thin film layer and the hologram layer become multiple reflections within the thin film layer. Known methods such as vacuum vapor deposition, reactive vacuum vapor deposition, sputtering, reactive sputtering, ion plating, and electroplating can be used to form this thin film layer. Further, other than those described in Table 1, it is preferable that the refractive index is higher than that of the hologram forming layer 6 (for example, refractive index n = 1.3 to 1.3). Other than Table 1, there are, for example, Bi ₂ O ₃ and CaO.SiO ₂ .

[0031]

[Table 1]

Further, for the hologram layer 8, a Lippmann hologram can be used as another hologram. This Lippmann hologram records a hologram image by forming portions having different densities, that is, portions having different refractive indexes in the layer. As the recording material, a light-sensitive material such as a silver salt emulsion, a gelatin emulsion, a photopolymerizable resin or a photocrosslinkable resin is used. This is subjected to exposure-development-fixing treatment to change the refractive index in the layer and record a hologram image.

In the reversible thermosensitive recording medium 1 of the present invention having the above-mentioned constitution, a reflective thin film layer 3, a photothermal conversion layer 4, a rewritable reversible thermosensitive recording layer 5 and a hologram layer 8 are successively formed on a substrate 2. From the front surface of the reversible thermosensitive recording medium 1 which is laminated, the hologram image by the hologram layer 8 is visually observed. Recording of visible information on the rewritable reversible thermosensitive recording layer 5 is performed by applying a semiconductor laser beam (infrared ray,
(About 700 to 1000 nm) according to a pattern of visible information, and the rewritable thermosensitive recording layer 5 which is rewritable by the heat generation of the photothermal conversion layer 4 is partially heated to maximize the reversible thermosensitive recording layer. It is possible to stably maintain the light-shielded state and the transparent state, or to reversibly change these states. Also, by setting one of the states as the base state, the optical difference from the other state can be obtained. The visible information recorded from can be read through the hologram image of the hologram layer 8.

Although not shown, a colored layer may be provided for the purpose of improving the visibility of the hologram image and the visible information and enhancing the design effect. For example, acrylic resin, styrene resin, polyester Resin,
A binder in which a dye or pigment of a desired color is dispersed using a vinyl resin or the like as a binder is used.

Further, a protective layer (not shown) may be provided on the outermost layer of the medium to protect the layers located therebelow, and the transparency is such that the visibility and detection of hologram images and visible information are not hindered. Any of those having, for example, known synthetic resins such as acrylic resin, urethane resin, vinyl chloride-vinyl acetate copolymer resin, polyester resin, melamine resin, epoxy resin, polystyrene resin,
Alternatively, a natural resin can be used. Further, as an additive for improving resistance based on ultraviolet ray or thermosetting resin, a curing agent such as isocyanate, waxes such as polyethylene wax and carnauba wax, extender pigments such as calcium carbonate, silica and alumina, silicone oils and fats, etc. Oils and fats can be used.

When the present invention is used as a seal or a label, a heat-sensitive adhesive or a pressure-sensitive adhesive (adhesive) is formed on the back surface of the substrate 2 as an adhesive layer. When a heat-sensitive adhesive is used for this adhesive layer, it is required that there is no effect on the heat-sensitive recording layer during adhesion by heating. It is possible to use a low temperature (100 ° C. or less) in the case of the flat press method and a relatively high temperature in the case of the heat roll method. Examples of adhesives include unsaturated polyester resins, urethane resins, thermosetting adhesives such as rubber and polyisocyanate, self-crosslinking acrylic adhesives, thermoplastic adhesives such as vinyl acetate, nylon, thermoplastic polyester, and even natural adhesives. Rubber latex, SBR latex,
Rubber-based adhesives such as NBR latex and butyl rubber are used.

Next, as shown in FIG. 2, the reversible thermosensitive recording medium 11 according to the second aspect of the present invention has a release layer 19, a hologram layer 18, and a rewritable reversible thermosensitive recording layer 15 on a support 12. A photothermal conversion layer 14 containing an infrared absorbing material that absorbs infrared rays and generates heat, a reflective thin film layer 13, and an adhesive layer 18 made of a heat sensitive adhesive or a pressure sensitive adhesive (adhesive) are sequentially provided. The hologram layer 18, the rewritable reversible thermosensitive recording layer 15, the photothermal conversion layer 14 containing an infrared absorbing material that absorbs infrared rays and generates heat, the reflective thin film layer 13, the thermosensitive adhesive or the pressure sensitive adhesive ( The adhesive layer 20 made of a pressure-sensitive adhesive) is the same as the above-mentioned same constituent layer.

The support 12 has tensile strength, heat resistance and the like, for example, a polyethylene terephthalate (PET) film, a white polyethylene terephthalate (PET) film in which titanium oxide or the like is kneaded, paper, vinyl chloride, AB.
Synthetic paper such as S, polyimide, metal foil, YUPO is used.

The peeling layer 19 peels off the transfer layer 21 below the hologram layer 18 from the support 12 at the time of transfer. For example, unsaturated polyester, melamine, epoxy,
Thermosetting resins such as various acrylates and polysilane resins, thermoplastic resins such as vinyl chloride and acrylic containing silicone oil and tetrafluoroethylene fine particles, polypropylene and the like are used. In particular, the peeling layer 19 after peeling can also serve as a protective layer for the hologram layer 18.

The reversible thermosensitive recording medium 11 is superposed on a transfer material (not shown) and heated from the support 12 side.
By applying pressure or pressure, the transfer layer 21 is adhered to the transfer material,
After that, the support 12 is peeled off to form a reversible thermosensitive recording medium in which the reversible reversible thermosensitive recording layer 14 and the hologram layer 18 are superposed on the transfer material. From the front of the reversible thermosensitive recording medium, the hologram image formed by the hologram layer 18 is visually observed. For recording visible information on the rewritable reversible thermosensitive recording layer, a semiconductor laser beam (infrared ray, about 700 to 1000 nm) is partially irradiated from above the hologram layer 18 according to a pattern of visible information, and the photothermal conversion layer 1
4. Rewritable reversible thermosensitive recording layer 15 is partially heated by the heat generated by 4 to stably maintain the reversible thermosensitive recording layer in the maximum light shielding state and the transparent state, or reversibly change these states. By setting either one of the states to the base state, the visible information recorded due to the optical difference from the other state can be read through the hologram image of the hologram layer 18.

The transfer layer 21 of the reversible thermosensitive recording medium 11 may be provided with a notch in a predetermined transfer pattern so as to facilitate transfer.

Although not shown, a colored layer may be provided for the purpose of improving the visibility of the hologram image and the visible information and enhancing the design effect. For example, acrylic resin, styrene resin, polyester. Resin,
A binder in which a dye or pigment of a desired color is dispersed using a vinyl resin or the like as a binder is used.

Further specific examples will be described in detail. <Example 1> As shown in FIG. 1, a substrate 2 made of a polyethylene terephthalate (PET) resin sheet (thickness 188 μm), a reflective thin film layer 3 made of an aluminum vapor deposition layer (thickness 500 Å), an infrared absorbent ( Product Name: CY-20
A photothermal conversion layer 4 formed by applying a coating liquid comprising Nippon Kayaku Co., Ltd. and polyparabanic acid as a binder, and a rewritable reversible thermosensitive recording layer 5 formed by coating a coating liquid having the following composition (layer thickness). 8 μm) and * rewritable reversible thermosensitive recording layer composition * behenic acid 4.0 parts by weight adipic acid 2.0 parts by weight 1,4-cyclohexanedicarboxylic acid 1.0 parts by weight VRPH (trade name) (Union Car) (Manufactured by Bite) 14.0 parts by weight Isocyanate 1.4 parts by weight Tetrahydrofuran 70.0 parts by weight A thermoplastic polyester resin is further applied, and hologram relief processing is performed using a stamper having a hologram image relief pattern formed on the upper surface thereof. Hologram formed by forming a hologram forming layer 6 and providing ZnS as a transparent thin film layer 7 on the relief forming surface by vacuum deposition. To obtain a reversible heat-sensitive recording medium 1 by sequentially laminating the beam layer 8.

When the obtained reversible thermosensitive recording medium 1 was observed from the front, a hologram image of the hologram layer could be visually recognized. In addition, infrared rays (wavelength 7
When information was written by irradiating the hologram layer 8 with 80 nm output (150 mW), opaque information could be recorded at the irradiated location, and this visible information was observed in superimposition with the hologram image. An infrared ray (wavelength: 780) was again applied to the cloudy portion of the reversible thermosensitive recording medium 1 by using a semiconductor laser.
(nm output 50 to 100 mW), the visible information was erased and only the hologram image was observed from the outside. Then, when the visible information was recorded again in the same manner, it was confirmed that the repetition of recording and erasing of the visible information did not affect the hologram image.

Example 2 Next, as shown in FIG. 2, a polyethylene terephthalate (PET) resin sheet (thickness 1
The hologram forming layer is formed by applying a release layer 17 made of a polysilane resin and a thermoplastic polyester resin to a support 12 made of 88 μm) and using a stamper having a hologram image relief pattern formed on the upper surface thereof to perform a hologram relief process. 16 and a hologram layer 18 formed by vacuum-depositing ZnS as a transparent thin film layer 17 on the relief forming surface, a rewritable reversible thermosensitive recording layer 15 (layer thickness 15 μm) having the above composition, an infrared absorber ( Product name: CY-20 manufactured by Nippon Kayaku Co., Ltd. and a photothermal conversion layer 14 formed by applying a coating liquid containing polyparabanic acid as a binder, a reflective thin film layer formed of an aluminum vapor deposition layer (thickness 500Å), unsaturated polyester The reversible thermosensitive recording medium 11 was obtained by sequentially laminating the adhesive layer 20 consisting of. This reversible thermosensitive recording medium 11 is adhered to an arbitrary substrate (for example, vinyl chloride sheet), and is adhered from the back surface thereof by pressure adhesion of a heat roll set at 100 ° C., and then the support 12 is peeled off. , A reversible thermosensitive recording medium was formed.

When this reversible thermosensitive recording medium was observed from the front, a hologram image of the hologram layer could be visually recognized. Furthermore, using a semiconductor laser, infrared rays (wavelength 780
When information was written by irradiating a hologram layer with 150 nm (nm output 150 mW), turbid information could be recorded at the irradiated location, and this visible information was observed in superimposition with the hologram image. When the cloudy portion of this reversible thermosensitive recording medium was irradiated again with infrared rays (wavelength 780 nm output 50-100 mW) using a semiconductor laser, visible information was erased and only a hologram image was observed from the outside. Then, when the visible information was recorded again in the same manner, it was confirmed that the gram image was not affected by the repeated recording and erasing of the visible information.

Further, in Example 1 and Example 2, when thermal printing was carried out by the thermal head of the printer attached to the commercially available word processor from the hologram layer of the reversible thermosensitive recording medium, it was clearly visible on the hologram image from the outside. There was a visible scar on the scanning of the thermal head. In this way, if the heating and printing means in the periphery is used, the trace of tampering remains, so that the tampering can be easily found and the fraudulent act can be suppressed.

[0048]

The reversible thermosensitive recording medium of the present invention comprises a hologram layer having a hologram image, a rewritable reversible thermosensitive recording layer, and a photothermal conversion layer, which are laminated so that a laser beam or the like can be removed from the upper surface of the hologram layer. Since the visible information is written under the hologram layer using the contact printing means,
Since the visible information can be recorded without affecting the hologram image, both can be confirmed in a state where the hologram image and the rewritable visible information are superimposed. Further, when the visible information is tampered with or altered, the hologram layer is damaged, so that the fact that the misconduct has been performed can be easily discriminated. As described above, the present invention has an excellent effect that not only the decorativeness of the hologram but also the presence or absence of an illegal act such as alteration or tampering of the visible information to be rewritten can be instantly confirmed, and a deterrent effect can be expected. .

[Brief description of drawings]

FIG. 1 is a partially enlarged sectional view showing an embodiment of a reversible thermosensitive recording medium of the present invention.

FIG. 2 is a partially enlarged sectional view showing an embodiment of the reversible thermosensitive recording medium of the second invention of the present invention.

[Explanation of symbols]

1, 11 reversible thermosensitive recording medium 2 substrate 3, 13 reflective thin film layer 4, 14 photothermal conversion layer 5, 15 rewritable reversible thermosensitive recording layer 6, 16 hologram forming layer 7, 17 transmissive thin film layer 8, 18 hologram layer 12 support 19 peeling layer 20 adhesive layer 21 transfer layer

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI G06K 19/10 G06K 19/00 DR (56) Reference JP-A-4-73193 (JP, A) JP-A-5-201182 (JP, A) JP 61-272772 (JP, A) JP 3-168944 (JP, A) JP 64-14077 (JP, A) JP 8-80680 (JP, A) (JP, A) 58) Fields investigated (Int.Cl. ⁷ , DB name) B41M 5/28-5/34 B41M 5/36 B42D 15/10 501 G03H 1/00-5/00

Claims (5)

(57) [Claims] 1. A reflective thin film layer on a substrate, a photothermal conversion layer containing an infrared absorbing material which absorbs infrared rays and generates heat, a rewritable reversible thermosensitive recording layer, and a finely textured photomask.
The refractive index is set to
A reversible thermosensitive recording medium comprising a hologram layer comprising a transparent thin film layer different from the hologram forming layer . 2. A support having a release layer and fine irregularities on the support.
The hologram layer and the surface with minute irregularities have a refractive index
The hologram layer comprising a transparent thin film layer different from the hologram forming layer , a rewritable reversible thermosensitive recording layer, a photothermal conversion layer containing an infrared absorbing material which absorbs infrared rays and generates heat, and a reflective thin film. A reversible thermosensitive recording medium comprising a layer and an adhesive layer. 3. The reversible thermosensitive recording layer contains a resin base material and an organic low molecular weight substance dispersed in the resin base material as main components,
The reversible thermosensitive recording medium according to claim 1 or 2, characterized in that its transparency reversibly changes depending on temperature. 4. The reversible heat-sensitive recording layer contains a leuco compound, a color-developing / reducing agent for thermally developing or reducing color by reacting with the leuco compound, and a binder as main components, and controlling the thermal energy, The reversible thermosensitive recording medium according to claim 1 or 2, which reversibly develops and erases color. 5. The reversible thermosensitive recording medium according to claim 1, wherein an adhesive layer is provided on the surface in contact with the adherend.