JPH05318972A - Information storage display medium - Google Patents

Abstract

PURPOSE:To provide an information storage display medium wherein magnetic recording is possible, repeated display can be performed with a high contrast as occasion demands, and printed part is clear. CONSTITUTION:A magnetic recording layer 1 is provided on one face of a support body 2. On other face of the support body, a light reflective layer 3, a thermosensitive layer 4, a masking layer 5, and a printing layer 6 are layered in sequence. The transparency of the thermosensitive layer 4 changes reversibly dependent on temperature. The masking layer 5 is formed on other part than an image display section of the thermosensitive layer 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information storage / display medium, and more particularly to an information storage / display medium capable of magnetic recording and capable of temporary display (image display) as required.

[0002]

2. Description of the Related Art Recently, various kinds of cards have been issued and used in large quantities, and examples thereof include a business card-sized telephone card and a so-called orange card (a ticket sales card of JR company). For these cards (magnetic cards), for example, 1, 50, ... 300 ,.
Numbers such as 0, ... Are printed, and the balance after use is displayed by holes formed between these numbers. Therefore, the balance can be accurately known only by using a telephone or a ticket vending machine that can use these cards, but in other cases, the balance cannot be accurately known.

In order to eliminate such inconvenience to some extent, a card in which the balance is displayed numerically by a thermal head using a heat-sensitive layer using a leuco dye or a heat-sensitive layer in which Sn is vapor-deposited on a magnetic recording layer is used. It has been put to practical use (JP-A-59)
-199284, JP-A-60-18388 and the like). However, these display methods have a drawback that the balance can be displayed but cannot be erased, so that the momentum and the amount of information that can be recorded are limited, and therefore the balance cannot be displayed despite the balance.

In view of such circumstances, the present inventors have previously described an information storage display medium capable of displaying / erasing a balance by using a heat-sensitive layer having a property that transparency reversibly changes depending on temperature. Proposed. However, in such an information storage display medium, when a light reflecting layer is provided below the reversible thermosensitive layer in order to further increase the display contrast, the contrast is good, but If a printing layer for advertising on a card is provided on the layer, the color tone of the ink used for printing cannot be reproduced on the information storage display medium, and the hue, lightness, and saturation of the color in the printed coloring part change. It is recognized that the printed part becomes opaque.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the inconveniences and inconveniences as described above, and it is possible to obtain repeated display of balance and the like with high contrast, and also when a printing layer is provided on the heat-sensitive layer. Provided is an information storage / display medium in which the hue, brightness, and saturation of the color of the printing coloring portion do not change and the printing portion is clear.

[0006]

In the information storage display medium of the present invention, a magnetic recording layer is provided on one surface of a support, a light reflection layer is provided on the opposite surface of the support, and the temperature is dependent on the light reflection layer. In addition, a heat-sensitive layer whose transparency changes reversibly is provided, a concealing layer is provided on the heat-sensitive layer other than the image display portion, and a print layer is further provided thereon. In this information storage display medium, it is more advantageous to provide a smooth layer between the support and the light reflecting layer.

The present inventors have studied the previously proposed information storage display medium, and as a result, (1) if a light reflecting layer is provided between the support and the reversible heat-sensitive layer, the display contrast becomes good. Further, it was confirmed that (2) a printed layer was made clear by providing a concealing layer on a portion other than the heat-sensitive layer image display portion on the heat-sensitive layer and further providing a printing layer thereon.

The present invention will be described in more detail below. Prior to making the present invention, the present inventors analyzed and examined the cause of the unclear printed portion observed in the conventional information storage and display medium, and the following was expected. That is, a substance emits a specific color because it absorbs a certain wavelength of visible light and reflects or transmits another part, and the color visually perceived at this time (complementary color)
Is generally known to be a portion of the reflected or transmitted wavelength other than the wavelength of the absorbed light, but when there is a light reflecting layer, the incident light is specularly reflected by the light reflecting layer. Therefore, it is considered that the color tone changes depending on the viewing angle, and as a result, the color tone of the printing coloring ink cannot be reproduced.

Next, the inventors of the present invention conducted a study to improve such a phenomenon, and as a result, it was confirmed that the printed portion became clear by providing the concealing layer in a portion other than the heat-sensitive layer image display portion. The function of the concealing layer is to prevent specular reflection of incident light by the light reflecting layer as described above and to radiate the light. As such a hiding layer,
Any color tone that does not interfere with the color tone of the print coloring portion may be used, preferably a pale color such as white, yellow, yellow green, and blue green, and more preferably white.

FIG. 1 is a cross-sectional view of three typical examples of the information storage display medium according to the present invention. FIG. 1 (a) has a magnetic recording layer 1 on one surface of a support 2 and an opposite surface thereof. An example in which a light reflecting layer 3, a heat-sensitive layer 4, a hiding layer 5, and a printing layer 6 are sequentially laminated, (b) is an example in which an overcoat layer 7 is further provided on the heat-sensitive layer 4 in (a) above, (C) is an example of the intermediate layer 8 provided between the heat-sensitive layer 4 and the overcoat layer 7 in (b).

The information storage display medium of the present invention utilizes the change in transparency (transparent state, cloudy opaque state) depending on temperature. The difference between the transparent state and the cloudy opaque state is as follows.
Inferred as (i) and (ii). (i) When transparent, the particles of the organic low-molecular substance dispersed in the resin matrix are composed of large particles of the organic low-molecular substance, and the light incident from one side is not scattered and the other side is not scattered. In the case of (ii) white turbidity, the particles of the organic low molecular weight substance are composed of polycrystals of fine crystals of the organic low molecular weight substance, and the crystal axis of each crystal is This is because light that is directed in various directions and is incident from one side is repeatedly refracted and scattered at the crystal interface of the organic low molecular weight substance particles, and thus appears white.

In FIG. 5 (representing the change in transparency depending on temperature), the heat sensitive layer 4 mainly composed of the resin base material and the organic low molecular weight substance dispersed in the resin base material is, for example, T It is cloudy and opaque at room temperature below ₀ . When it is heated to a temperature between T _{1 and} T ₂ , it becomes transparent, and in this state it remains transparent even if it is returned to room temperature below T ₀ . It is considered that this is because the organic low-molecular-weight substance undergoes a semi-molten state until the temperature falls from T _{1 to} T ₂ to T ₀ or less and the crystal grows from a polycrystal to a single crystal. Further heating to a temperature of T ₃ or higher results in a semitransparent state between the maximum transparency and the maximum opacity. Next, when this temperature is lowered, the first cloudy opaque state is restored without taking the transparent state again. This is the temperature T
It is considered that when the organic low molecular weight substance is ₃ or more, the polycrystal is precipitated by cooling after melting. After heating this opaque state to a temperature between T _{0 and} T ₁ ,
When cooled to room temperature, that is, to a temperature of T ₀ or lower, a state between transparent and opaque can be obtained. Also, the transparent material that has become transparent at room temperature is heated to a temperature of T ₃ or higher again, and returns to room temperature to return to a cloudy opaque state. That is, it can take both opaque and transparent forms at room temperature and intermediate forms thereof. Therefore, the heat sensitive layer 4 can be selectively heated by selectively applying heat to form a cloudy image on a transparent background and a transparent image on a cloudy background, and the change can be repeated many times. ..

To make the information storage display medium of the present invention,
According to the example shown in FIG. 1 (a), a magnetic material is vacuum-deposited or sputtered on one surface of the support 2 which is a transparent or white plastic film such as a polyester film, paper or the like or a colored material thereof. Method, or apply a magnetic material together with a resin binder.
A magnetic recording layer 2 is formed by drying, a metal thin film is formed on a support on the opposite surface to form a light reflecting layer 3, a heat sensitive layer 4 is formed on the light reflecting layer 3, and a heat sensitive layer is formed thereon. The concealing layer 5 and the printing layer 6 may be sequentially formed on a portion of the layer 4 other than the image display portion.

Examples of the magnetic material in the magnetic recording layer 1 include iron, cobalt, nickel, etc. and their alloys or compounds. Examples of the resin binder include various thermoplastic resins, thermosetting resins, ultraviolet curable resins, electron beam curable resins and the like. The light reflecting layer 3 is formed by vacuum vapor deposition, ion plating, sputtering, CV.
A metal thin film (thickness 200 to 1000Å) formed by the D method or the like can be preferably used, but the metal used here may be any as long as it reflects light, for example, Al, G
e, Au, Ag, Cu and alloys thereof.

The heat-sensitive layer (reversible heat-sensitive recording layer) 4 is generally a solution in which two components of (1) a resin base material and an organic low molecular weight substance are dissolved, or a solution of a resin base material (an organic low molecular weight substance as a solvent). A liquid in which an organic low-molecular substance is dispersed in a fine particle form is applied to a target surface and dried, or (2) the above two components are used in the presence or absence of a solvent. It may be prepared by kneading in the presence, heating if necessary, and shaping into a sheet, and using itself as a heat-sensitive sheet. The solvent for forming the heat-sensitive layer can be variously selected depending on the type of the base material and the organic low molecular weight substance, and examples thereof include tetrahydrofuran, methyl ethyl ketone, methyl isobutyl ketone, chloroform, carbon tetrachloride, ethanol, toluene, benzene and the like. The organic low molecular weight substance is precipitated as fine particles and exists in a dispersed state in the heat-sensitive layer obtained not only when the dispersion liquid is used but also when the solution is used.

The resin base material used for the heat-sensitive layer 4 is a material that forms a layer in which an organic low molecular weight substance is uniformly dispersed and held, and affects the transparency at the time of maximum transparency. Therefore, the resin base material is preferably a resin having good transparency, mechanical stability, and good film forming property. Examples of such resins include polyvinyl chloride; vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-vinyl alcohol copolymer, vinyl chloride-vinyl acetate-maleic acid copolymer, vinyl chloride-acrylate copolymer. Vinyl chloride-based copolymers such as polyvinylidene chloride, vinylidene chloride-vinyl chloride copolymers, vinylidene chloride-based copolymers such as vinylidene chloride-acrylonitrile copolymers, polyesters, polyamides, polyacrylates or polymethacrylates or acrylates- Methacrylate copolymer; silicone resin and the like can be mentioned. These may be used alone or in admixture of two or more.

On the other hand, the organic low molecular weight substance may be any substance that changes from polycrystal to single crystal in the heat-sensitive layer 4 depending on the temperature, and generally has a melting point of 30 to 200 ° C., preferably 50 to 15
The thing of about 0 degreeC is used. Such organic low molecular weight substances include alkanols; alkane diols; halogen alkanols or halogen alkane diols; alkylamines; alkanes; alkenes; alkynes; halogen alkanes; halogen alkenes; halogen alkynes; cycloalkanes; cycloalkenes; cycloalkynes; Unsaturated mono- or dicarboxylic acids or their esters, amides or ammonium salts; Saturated or unsaturated halogen fatty acids or their esters, amides or ammonium salts; Allylcarboxylic acids or their esters, amides or ammonium salts; Acids or their esters, amides or ammonium salts; Thioalcohols; Thiocarboxylic acids or their esters, amines or ammonium salts Carboxylic acid esters of thio alcohol. These may be used alone or in combination of two or more. The carbon number of these compounds is 10 to 60, preferably 10 to 38,
Particularly, 10 to 30 is preferable. The alcohol group portion in the ester may be saturated or may be halogen-substituted. In any case, the organic low molecular weight substance is at least one kind of oxygen, nitrogen, sulfur and halogen in the molecule, for example,
OH, -COOH, -CONH, -COOR, -NH,
_{-NH 2, -S -, - S} -S -, - O-, is preferably a compound containing a halogen and the like.

More specifically, these compounds include laurin
Acid, dodecanoic acid, myristic acid, pentadecanoic acid, pal
Mitic acid, stearic acid, behenic acid, nonadecanoic acid, a
Higher fatty acids such as laginic acid and oleic acid; stearic acid
Chill, tetradecyl stearate, octastearate
Decyl, octadecyl laurate, tetra palmitate
Esters of higher fatty acids such as decyl and dodecyl behenate; C₁₆H₃₃-O-C₁₆H₃₃ , C₁₆H₃₃-S-C₁₆H₃₃ , C₁₈H₃₇-S-C₁₈
H₃₇ , C₁₂H_{twenty five}-S-C₁₂H_{twenty five} , C₁₉H₃₉-S-C₁₉H₃₉ , C₁₂H
_{twenty five}-S-S-C₁₂H_{twenty five} , Etc., such as ether or thioether. Above all, the present invention
Higher fatty acids, especially palmitic acid, stearic acid,
Higher fats with 16 or more carbon atoms such as henic acid and lignoceric acid
Acids are preferable, and higher fatty acids having 16 to 24 carbon atoms are more preferable.
Good.

In order to widen the range of temperature at which the material can be made transparent, the organic low molecular weight substances described in this specification may be combined appropriately, or such organic low molecular weight substances may be combined with other materials having different melting points. Good. These are disclosed in, for example, JP-A-63-39378, JP-A-63-130380, Japanese Patent Application No. 63-14754, Japanese Patent Application No.
However, the present invention is not limited thereto.

The weight ratio of the organic low molecular weight substance to the resin base material in the heat sensitive layer is preferably about 2: 1 to 1:16,
It is more preferably 1: 1 to 1: 3. When the ratio of the resin base material is less than this, it becomes difficult to form a film in which the organic low molecular weight substance is retained in the resin base material. Becomes difficult.

The thickness of the heat sensitive layer 4 is preferably 1 to 30 μm, more preferably 2 to 20 μm. If the heat-sensitive layer is too thick, heat distribution will occur in the layer and it will be difficult to achieve uniform transparency. On the other hand, if the heat-sensitive layer is too thin, the white turbidity is lowered and the contrast is lowered. Further, the white turbidity can be increased by increasing the amount of the organic low molecular weight substance in the heat sensitive layer.

In addition to the above components, additives such as a surfactant and a high boiling point solvent may be added to the heat-sensitive layer in order to facilitate the formation of a transparent image. Specific examples of these additives are as follows. Examples of high boiling point solvents: tributyl phosphate, tri-2-phosphate
Ethylhexyl, triphenyl phosphate, tricresyl phosphate, butyl oleate, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diheptyl phthalate, di-n-octyl phthalate, di-2-ethylhexyl phthalate, diisononyl phthalate , Dioctyldecyl phthalate, diisodecyl phthalate, butylbenzyl phthalate,
Dibutyl adipate, di-n-hexyl adipate, di-2-ethylhexyl adipate, di-2 azelaate
-Ethylhexyl, dibutyl sebacate, di-2-ethylhexyl sebacate, diethylene glycol dibenzoate, triethylene glycol di-2-ethyl butyrate, methyl acetylricinoleate, butyl acetylricinoleate, butylphthalylbutyl glycolate, acetylcitric acid Tributyl.

Examples of surfactants and other additives; polyhydric alcohol higher fatty acid ester; polyhydric alcohol higher alkyl ether; polyhydric alcohol higher fatty acid ester, higher alcohol, higher alkylphenol, higher fatty acid higher alkylamine, higher fatty acid amide , Lower olefin oxide adducts of fats and oils or polypropylene glycol; acetylene glycol; Na, Ca, Ba or Mg salt of higher alkylbenzene sulfonic acid; higher fatty acid, aromatic carboxylic acid, higher fatty acid sulfonic acid, aromatic sulfonic acid, sulfuric acid monoester Or Ca, Ba or Mg salt of phosphoric acid mono- or di-ester; low degree of sulfated oil; poly long chain alkyl acrylate; acrylic oligomer; poly long chain alkyl methacrylate; long chain alkyl methacrylate-amine containing mono Over copolymer; a styrene - maleic anhydride copolymer; olefin - maleic anhydride copolymer.

In the present invention, when the light reflection layer 3 is made of a material such as an Al vapor deposition layer which has a poor adhesion to the resin, an adhesive layer may be provided between the support 2 and the light reflection layer 3. Good (JP-A-3-7377).

An overcoat layer 7 is formed on the heat-sensitive layer 4 of the present invention in order to prevent the transparency of the transparent portion from being lowered due to the deformation of the surface due to the heat and pressure of the heating means such as a thermal head. It may be provided. The material of the overcoat layer (thickness 0.1 to 10 μm) laminated on the heat-sensitive layer is silicone rubber or silicone resin (Japanese Patent Laid-Open No. 63-2.
No. 21087), polysiloxane graft polymers (described in Japanese Patent Application No. Sho 63-221087), UV curable resins, electron beam curable resins (described in Japanese Patent Application No. 2-566), and the like.

In any case, a solvent is used at the time of coating, but it is desirable that the solvent is difficult to dissolve the resin of the heat sensitive layer and the organic low molecular weight substance. Examples of the solvent that hardly dissolves the resin of the heat-sensitive layer and the organic low-molecular substance include n-hexane, methyl alcohol, ethyl alcohol, isopropyl alcohol, and the like, and the alcohol solvent is particularly preferable from the viewpoint of cost.

Further, an intermediate layer 8 can be provided between the overcoat layer 7 and the heat-sensitive layer 4 in order to protect the reversible recording material from the solvent of the overcoat layer forming liquid, the monomer components and the like (Japanese Patent Laid-Open No. Hei 10 (1999) -58242). 1-133781). As the material of the intermediate layer 8, the following thermosetting resins and thermoplastic resins can be used in addition to those listed as the resin base material in the heat sensitive layer 4. That is, specifically, polyethylene, polypropylene, polystyrene, polyvinyl alcohol,
Examples thereof include polyvinyl butyral, polyurethane, saturated polyester, unsaturated polyester, epoxy resin, phenol resin, polycarbonate and polyamide. Although the thickness of the intermediate layer 8 varies depending on the use, it is preferably about 0.1 to 2 μm. When it is less than this, the protection effect decreases,
If it is more than this, the thermal sensitivity is lowered.

Next, the method for forming the masking layer 5 used in the present invention is as follows. To form the concealing layer 5, a solution or dispersion containing a colorant and a resin binder as main components is applied onto the heat-sensitive layer 4 or the overcoat layer 7 and dried, or by simply attaching a coloring sheet. It is formed. Here, the white colorants preferably used include inorganic substances such as calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, kaolin, talc, surface-treated calcium and silica. In addition to the system fine powder, organic fine powder such as urea-formalin resin, styrene-methacrylic acid copolymer, polystyrene resin and vinylidene chloride resin can be used. Further, as the resin binder, the above-mentioned various thermoplastic, thermosetting or ultraviolet curable resins are used. Here, the thickness of the hiding layer 5 is preferably 1 to 20 μm, more preferably 2 to 15 μm. The coloring density of the hiding layer 5 is preferably 0.50 or less in terms of the reflection density value of the Macbeth reflection type densitometer RD914 visual filter.
It is preferably 0.30 or less, more preferably 0.20 or less.

The printing layer 6 is formed by printing or writing necessary information on the concealing layer 5.

In the information storage display medium according to the present invention, which has been described above, the intended object can be achieved by providing the light reflection layer directly on the support. However, in some cases, such an information storage display medium may have a phenomenon in which light is diffusely reflected by fine irregularities on the support, which hinders the effect of improving contrast.

Therefore, in order to avoid such an unexpected situation, as shown in FIG. 2, it is preferable to provide a smoothing layer 9 containing a resin as a main component between the support 2 and the light reflecting layer 3. It is advantageous. As the resin, a thermoplastic resin, a thermosetting resin, or a radiation curable resin is used. Among them, a curable resin is preferable, and a curable resin by ultraviolet rays or electron beams is more preferable.

By forming this smooth layer 9,
The unevenness of the support 2 is alleviated, and the situation that the contrast effect due to diffused reflection of light is lost can be avoided. FIG. 2 is a schematic diagram of three examples of the information storage / display medium according to the present invention, which is slightly different from FIG. 1, in which a smoothing layer 9 is further provided.

Now, the support body 2'having irregularities formed on its surface
In order to apply a high molecular weight polymer from the beginning in order to smooth the surface, it is necessary to dissolve the polymer in a solvent or the like in an amount of about 5 to 20% to reduce the viscosity and then apply (FIG. 3).
(A)). 91 is this coating liquid. When it is heated to evaporate the solvent and dried, the coating layer 91 'is formed along the irregularities of the base and does not become smooth (FIG. 3 (b)).

On the other hand, when a UV curable resin or an electron beam curable resin which is a low molecular weight monomer or oligomer at the time of coating and becomes a polymer by being irradiated with UV rays or an electron beam after coating is used, Even if the active ingredient is as high as several tens of percent, it has a low viscosity and can be applied uniformly, and since it has a small amount of solvent, it can maintain smoothness even when dried (FIG. 4).
(A) and (b)). In the figure, FIG. 4A shows a coating liquid 92 of an ultraviolet curable resin or an electron beam curable resin, and FIG. 4B shows a coating layer 92 'of an ultraviolet curable resin or an electron beam curable resin. ing. The coating layer shown in FIG. 4 (b) directly forms the smooth layer 9 in the present invention.

As described above, a solvent or the like may be used for forming the smooth layer 9, and the solvent in this case may be the same as the solvent for forming the heat sensitive layer 4. Further, instead of these solvents, a photopolymerization initiator can be used as a reactive diluent for easy handling. 2-ethylhexyl acrylate as a photopolymerization initiator,
Cyclohexyl acrylate, butoxyethyl acrylate, neopentyl glycol diacrylate, 1,6
-Hexanediol diacrylate, polyethylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate and the like can be mentioned.

The ultraviolet curable resin used for forming the smooth layer 9 may be any monomer or oligomer (or prepolymer) that undergoes a polymerization reaction upon irradiation with ultraviolet rays and is cured to become a resin. Examples of such a monomer or oligomer include (poly) ester acrylate,
(Poly) urethane acrylate, epoxy acrylate, polybutadiene acrylate, silicone acrylate, and melamine acrylate.

The (poly) ester acrylate is 1,6-
It is obtained by reacting a polyhydric alcohol such as hexanediol, propylene glycol (as propylene oxand) and diethylene glycol with a polybasic acid such as adipic acid, phthalic anhydride, trimellitic acid and acrylic acid.
The structural examples are shown in (a) to (c). (A) Adipic acid / 1,6-hexanediol / acrylic acid

[Chemical 1] (B) Phthalic anhydride / Propylene oxide / Acrylic acid

[Chemical 2] (C) trimellitic acid / diethylene glycol / acrylic acid

[Chemical 3]

The (poly) urethane acrylate is obtained by reacting a compound having an isocyanate group such as tolylene diisocyanate (TDI) with an acrylate having a hydroxy group. An example of the structure is shown in (d). HEA
Is 2-hydroxyethyl acrylate, HDO is 1,6-hexanediol, and ADA is adipic acid. (D) HEA / TDI / HDO / ADA / HDO / TDI / HEA

[Chemical 4]

Epoxy acrylates are roughly classified into bisphenol A type, novolak type and alicyclic type,
The epoxy group of these epoxy resins is esterified with acrylic acid to make the functional group an acryloyl group. Examples of the structure are shown in (e) to (g). (E) Bisphenol A-epichlorohydrin type / acrylic acid

[Chemical 5] (F) Phenol novolac-epichlorohydrin type / acrylic acid

[Chemical 6] (G) Alicyclic / acrylic acid

[Chemical 7]

Polybutadiene acrylate is obtained by reacting terminal OH group-containing 1,2-polybutadiene with isocyanate, 2-mercaptoethanol or the like, and then further reacting with acrylic acid or the like. An example of the structure is shown in (h). (H)

[Chemical 8]

The silicone acrylate is, for example, methacryl-modified by a condensation reaction (demethanol reaction) of an organofunctional trimethoxysilane and a silanol group-containing polysiloxane, and its structural example is shown in (i). (I)

[Chemical 9]

On the other hand, as the electron beam curable resin material, the ultraviolet curable resin can be used as it is. By the way, an electron beam has a larger energy and a larger penetrating power than an ultraviolet ray. Therefore, particularly when a pigment or the like is put in the smooth layer 9, the electron beam can reach the inside. Thus, electron beam curing can form a denser and more uniform network structure than ultraviolet curing, and thus it can be expected to exhibit even more excellent durability. Also, the energy required for electron beams to cure is about one-third that of ultraviolet rays,
Capital investment is large, but if demand is high, it can be expected to reduce costs. The thickness of the smooth layer 9 is preferably thin, and is about 0.2 to 3.0 μm.

[0043]

EXAMPLES The present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. In addition, both parts and% are based on weight.

Example 1 γ-Fe ₂ O ₃ 10 parts Vinyl chloride-vinyl acetate-vinyl alcohol copolymer (VAGH manufactured by UCC) 2 parts Coronate L (10% toluene solution) 2 on white PET having a thickness of about 188 μm Part Methyl ethyl ketone 43 parts Toluene 43 parts A solution consisting of 43 parts is applied with a wire bar and dried by heating to about 1
A magnetic recording layer having a thickness of 0 μm was provided. Next, Al was vacuum-deposited on the white PET on the opposite surface of the magnetic recording layer to a thickness of about 400 Å to form a light reflection layer. Further thereon, stearic acid 5 parts eicosane diacid 5 parts diisodecyl phthalate 2 parts vinyl chloride-vinyl acetate-phosphate ester copolymer (Denka Vinyl # 1000P manufactured by Denki Kagaku Kogyo Co., Ltd.) 25 parts THF 150 parts toluene A 15-part liquid was applied and dried by heating to provide a heat-sensitive layer (reversible heat-sensitive recording layer) having a thickness of about 5 μm. Further, a solution of 10 parts of polyamide resin (CM8000, manufactured by Toray Industries, Inc.) and 50 parts of methanol was applied on it, and dried by heating to form an intermediate layer having a thickness of about 1 μm. Furthermore, a 75% butyl acetate solution of urethane acrylate UV curable resin (Unidick C7-157, manufactured by Dainippon Ink and Chemicals, Inc.) 10 parts A solution consisting of 10 parts toluene was applied with a wire bar to give 80 W / cm. Was cured by an ultraviolet lamp of No. 2 to provide an overcoat layer having a thickness of about 2 μm. Next, a white polyester film was attached as a concealing layer to the portion of the heat-sensitive layer other than the image display portion on the heat-sensitive layer, and UV of Best Cure Thermal 29 Blue K-5 manufactured by Toka Dye Co. was further applied on the white polyester film.
The ink was offset-printed and irradiated with ultraviolet rays from a UV lamp of 120 W / cm for 5 seconds to be cured to prepare an information storage display medium of the type shown in FIG. 1 (c).

Example 2 The concealment layer was formed from the white polyester film of Example 1 Titanium oxide 10 parts UV curable resin (FS-1059 manufactured by Mitsubishi Rayon Co., Ltd.) 5 parts Toluene 10 parts A liquid dispersion of the thermosensitive layer Information was obtained in the same manner as in Example 1 except that screen printing was performed on a portion other than the display portion, heating and drying, and then irradiation with an ultraviolet lamp of 120 W / cm for 2 seconds to cure and cure the ultraviolet rays to provide a hiding layer having a thickness of about 10 μm. I made a memory display medium.

Example 3 Between the white PET of Example 1 and the light reflecting layer, a special acrylic UV curable resin (Unidick C7-164 49% butyl acetate solution manufactured by Dainippon Ink and Chemicals, Inc.) 10 parts Toluene 4 parts After applying the solution consisting of
An information storage display medium was prepared in the same manner as in Example 1 except that ultraviolet rays were irradiated for 5 seconds with a 0 W / cm ultraviolet lamp to provide a smoothing layer having a thickness of about 1.0 μm.

Example 4 An information storage display medium was prepared in the same manner as in Example 2 except that a smoothing layer similar to that in Example 3 was provided between the white PET and the light reflecting layer in Example 2.

Comparative Example 1 An information storage display medium was prepared in the same manner as in Example 1 except that the hiding layer was not provided.

Comparative Example 2 An information storage display medium was prepared in the same manner as in Example 2 except that the hiding layer was not provided.

Comparative Example 3 An information storage display medium was prepared in the same manner as in Example 3 except that the hiding layer was not provided.

Comparative Example 4 An information storage display medium was prepared in the same manner as in Example 4 except that the hiding layer was not provided in Example 4.

Comparative Example 5 An information storage display medium was prepared in the same manner as in Example 1 except that the light reflecting layer and the hiding layer were not provided.

After heating these nine types of information storage display media to make the reversible thermosensitive recording layer transparent, energy of 1 mj / dot was applied by a thermal head to form a cloudy image. Table 1 shows the image density, background density, and contrast at that time. Further, the hue, lightness, and saturation of the color of the printed portion were visually confirmed and the rank was evaluated. The results are also shown in Table 1.

[0054]

[Table 1]

[0055]

As is apparent from the description of the embodiments, the information storage display medium of the present invention has the light reflecting layer provided between the support and the heat sensitive layer, and thus a rewritable display with high contrast is obtained. In addition, even when a print layer is provided on the heat-sensitive layer or overcoat layer, the effect of the concealing layer provided between them does not change the hue, brightness, and saturation of the color of the print part, and the print part is clear. An information storage display medium can be obtained.

[Brief description of drawings]

1A, 1B and 1C are sectional views of three examples of an information storage display medium according to the present invention.

2 (a), (b) and (c) are sectional views of another three examples of the information storage display medium according to the present invention.

3 (a) and 3 (b) are views for explaining an example of failure of means for making a support smooth.

4 (a) and 4 (b) are views for explaining a good example of means for making the support smooth.

FIG. 5 is a diagram for explaining a change in transparency depending on the temperature of the thermosensitive layer (reversible thermosensitive recording layer) in the present invention.

[Explanation of symbols]

 1 Magnetic Recording Layer 2 Support 3 Light Reflecting Layer 4 Thermosensitive Layer (Reversible Thermosensitive Recording Layer) 5 Hiding Layer 6 Printing Layer 7 Overcoat Layer 8 Intermediate Layer 9 Smoothing Layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Makoto Kawaguchi 1-3-6 Nakamagome, Ota-ku, Tokyo Within Ricoh Co., Ltd.

Claims (2)

[Claims] 1. A magnetic recording layer is provided on one surface of a support,
A light-reflecting layer is provided on the opposite surface of the support, and a heat-sensitive layer whose transparency reversibly changes depending on temperature is provided on the support, and a concealing layer is further provided on the heat-sensitive layer on a portion other than the image display portion. Provided,
An information storage display medium, further comprising a print layer provided thereon. 2. The information storage display medium according to claim 1, further comprising a smoothing layer provided between the support and the light reflecting layer.