JP2019095582A - Display recording body - Google Patents

Abstract

To provide a display recording body that orients magnetic powder by application of magnetism and displays an image, which has good contrast between a printing part and a non-printing part, is excellent in stability of an image, is excellent in repetition resistance, and is suitable for color display by selectively using magnetic fine particles having specific colors.SOLUTION: There is provided a display recording body in which a coloring layer is laminated on a support body formed of a non-magnetic material, and an inorganic material layer containing an inorganic material having a high thermal conductivity, a reversible heat-sensitive layer which contains a resin matrix and an organic low molecular substance dispersed in the resin matrix as main components, depends on the temperature and has reversively changing transparency, and a magnetic recording layer in which microcapsules including the magnetic powder and the dispersion medium are dispersed and arranged in a binder are laminated in this order thereon, wherein the magnetic powder is magnetic powder exhibiting a specific color, and a layer thickness of the reversible heat-sensitive layer is 10-100 μm.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a laminate of a reversible thermosensitive recording layer which brings about a reversible transparency change by thermal energy and a magnetic recording layer for orienting magnetic powder by applying magnetism and displaying an image, and a printed part and an unprinted part. The present invention relates to a display recording material suitable for color display by properly using magnetic powder fine particles having a specific color, having a good contrast with the part, an excellent image stability, and an excellent repeated resistance.

  Conventionally, as a magnetic recording medium utilizing magnetism, for example, as described in Patent Document 1 below, magnetic particles are moved by causing a magnetic field to act on a suspension in which magnetic particles are dispersed in a dispersion medium. There is known a method of performing display by changing the color of a colored dispersion medium.

  However, in such a magnetic recording medium, when the suspension is sealed between two substrates and characters and patterns are drawn from one of the substrates with a magnetic pen to apply magnetism, the magnetic particles of the suspension are attracted and it is as it is However, since the specific gravity of the magnetic particles is much larger than that of the dispersion medium, the attracted magnetic particles settle with time, so that the characters and patterns can not be held for a long time.

  In addition, since all magnetic particles that have received magnetism by the magnetic pen are attracted to the magnetic pen, the magnetic particles that were present away from the magnetic pen are also attracted, so there is a defect that only unclear characters and patterns can be obtained. Was. In order to prevent sedimentation of the magnetic particles, for example, when the magnetic particles are finely divided or the magnetic particles are coated with a polymer having a low specific gravity to approximate the apparent specific gravity of the magnetic particles to that of the dispersion medium, the magnetic acts on the magnetic particles. Since the force is extremely small, it is difficult to be attracted by the magnetic pen, resulting in a defect that sharp letters and patterns with high density can not be obtained.

  Furthermore, if the apparent specific gravity of the magnetic particles is made similar to that of the dispersion medium, the magnetic particles are difficult to be attracted to the opposite side of the substrate even when erasing characters or patterns, and can not be erased completely. It was totally dark and not practical.

  As a mode for solving these drawbacks, for example, as described in Patent Document 2 and Patent Document 3, by using a liquid having a yield value of a certain value or more, or a thickener as a dispersion medium, A magnetic recording medium is known which can display clear, high-contrast characters and images without blurring, can stably hold the display for a long time, and can completely erase data.

  However, this magnetic recording medium is formed so that honeycomb cells each having a side and a depth of about 2 mm are provided on the entire surface of the transparent plastic sheet, and the magnetic particles and the white pigment are dispersed in the cells. The suspension dispersed in the above was injected, and this was sealed by a transparent sheet, and had the following drawbacks.

  That is, it is impossible to make the resolution of the image smaller than that of the honeycomb-shaped cells, since the magnetic particles are moved from the back to the surface in the honeycomb-shaped cells to form an image. In addition, it is difficult to form a honeycomb-shaped cell, to enlarge or greatly reduce the size of the honeycomb-shaped cell, and to perform a process of injecting suspension into the honeycomb-shaped cell.

As another form, for example, as described in Patent Document 4 and Patent Document 5, unlike the magnetic recording material in which the magnetic particles and the pigment are sealed in the honeycomb-like cells as described above, the magnetic particles are microcapsulated. A magnetic recording medium is known, in which the magnetic recording medium is sealed and coated on a support. According to this method, the resolution can be increased by controlling the particle size of the microcapsules, and the manufacturing process is also easy. In addition, various films can be selected as the substrate to which the microcapsules are applied, and the shape and size can be freely selected.

However, the image formation shown here is performed in the following manner. First, the light absorbing magnetic particles in the microcapsules are attracted to the back side of the magnetic recording medium by the permanent magnet, and the light reflecting nonmagnetic particles remain on the surface of the magnetic recording medium accordingly, whereby the surface is made smaller. It becomes the color of non-magnetic particles and is in the erased state.
Next, by applying and recording magnetism from the surface of the magnetic recording medium with a permanent magnet, the light absorbing magnetic particles are attracted to the surface by magnetism, and desired characters and images are formed.
Therefore, in such an image formation, it takes time for the nonmagnetic particles and the magnetic particles to be interchanged, resulting in a magnetic recording medium with poor sensitivity.

  Furthermore, as another form using a microcapsule, for example, as described in Patent Document 6, Patent Document 7, Patent Document 8, Patent Document 9, Patent Document 10, or Non-Patent Document 1, flakes Magnetic recording materials in which light-reflective magnetic particles of the type described above are encapsulated in microcapsules are known.

  In the method of forming an image according to this embodiment, at the time of production of the magnetic recording medium, all the incident light is reflected and brightened by orienting the magnetic particles in the coated capsule in parallel with the plane of the magnetic recording medium beforehand. Next, by performing magnetic recording, the magnetic particles rotate to scatter and absorb incident light, so that a contrast is generated and a black image is formed.

  However, in the magnetic recording medium obtained in this manner, when there is no colored layer in the lower layer of the recording layer, the contrast between the printed portion and the unprinted portion is not so large and practically insufficient, while the black in the recording lower layer Even when a colored layer other than the above was provided, the color became dark, and only colors with low brightness could be expressed. Furthermore, since the above magnetic recording material can be easily printed and erased by the magnetic force, the image is formed so that fogging occurs in the unprinted portion or the image is erased simply by touching the magnet. It has the disadvantage of poor stability.

  On the other hand, as described in Patent Document 11, microcapsules containing at least flake-like magnetic powder and a dispersion medium exhibiting a solid phase at normal temperature formed by dispersing the magnetic particles are dispersed in the recording layer. According to this method, the dispersion medium in the microcapsules is solid at normal temperature, so that the unprinted area may be fogged or the image may be erased only by touching the magnet. The stability of the image against the magnetic force is good.

  In addition, even if heat is accidentally applied due to a heater in winter or a car in summer, the magnetic powder does not move by heat alone, so that the stability of the image to heat is good. However, even in this case, since the magnetic powder is black or metallic luster color, when the color of the colored layer in the lower layer of the recording layer is other than black, the color becomes dark and only the color with low lightness is sufficiently expressed. It can not be done.

Further, in the method of controlling magnetic powder magnetically, it is mainly possible to switch only two colors, and it is difficult to change the color tone or color development of three or more colors.
Further, as described in Patent Document 12, a plurality of magnetic recording layers, in which flake-like magnetic powder and microcapsules containing a colored dispersion medium are dispersed, are laminated, and the magnetic strength of each layer is applied. There is a method to control the color, but with this method it is difficult to control the magnetism and color mixing occurs in each layer.

Patent Documents 13 and 14 disclose reversible thermosensitive recording materials capable of repetitively recording and erasing information utilizing the property that optical characteristics cause reversible changes in the state of transparency and white turbidity by thermal energy. There are known reversible thermosensitive recording materials in which organic low molecular weight substances such as higher fatty acids are dispersed in a resin matrix such as vinyl chloride-vinyl acetate copolymer.

  This type of reversible thermosensitive recording material is used to shift the reversible thermosensitive recording layer from the turbid state to the transparent state, in particular, in order to control the writing / erasing device stably, so as to be able to be transparent stably. It was necessary to keep the clearing temperature range of the layer wide. Therefore, with regard to the organic low molecular weight substance dispersed in the resin base material, at least one kind of higher fatty acid having 16 or more carbon atoms and at least one kind of aliphatic saturated dicarboxylic acid and its derivative are dispersed in the resin as a uniform system. It has been proposed that the transparent temperature range of the reversible thermosensitive recording layer can be expanded by using the same (Patent Document 15), and the number of carbon atoms as the organic low-molecular substance dispersed in the above-mentioned resin matrix is also proposed. The transparentizing temperature range of the reversible thermosensitive recording layer by dispersing and using at least one of 16 or more higher fatty acids and at least one of aliphatic saturated dicarboxylic acid having 20 or more carbon atoms and its derivative as a uniform system in a resin A configuration that makes it possible to expand is proposed. (Patent Document 16).

  Furthermore, as described in Patent Document 17, by adding an alicyclic dicarboxylic acid to an organic low molecular weight substance dispersed in a resin matrix, the clearing temperature range of the reversible thermosensitive recording layer can be dramatically increased. US Pat. No. 6,095, 660, which discloses an arrangement that allows the use of a thermal head as a means of transitioning from a cloudy state to a transparent state.

  In the case of erasing with a thermal head, it is necessary to heat the contact portion of the recording layer to the clearing temperature range by instantaneous heating, and in view of the final temperature difference reached in the depth direction during heating, There was a need to expand the temperature range.

  However, the expansion of the clearing temperature range of the reversible thermosensitive recording layer according to the above-described configuration is mainly extended to the high temperature side. Therefore, it is also necessary to increase the heating temperature for the clouding, so that the clouding energy becomes large, and a general-purpose thermal printer can not be used.

Japanese Patent Application Laid-Open No. 48-56393 Japanese Patent Publication No. 57-27463 JP-A-62-53359 Japanese Patent Application Laid-Open No. 2-146082 Unexamined-Japanese-Patent No. 4-233581 Unexamined-Japanese-Patent No. 1-145637 Japanese Patent Application Laid-Open No. 63-153197 Japanese Examined Patent Publication 4-7518 Japanese Patent Laid-Open No. 6-79986 Japanese Patent Application Laid-Open No. 6-92068 JP-A-8-175059 JP-A-9-50052 JP-A-54-119377 Japanese Patent Application Laid-Open No. 55-154198 Japanese Patent Application Laid-Open No. 2-1363 Unexamined-Japanese-Patent No. 3-2089 JP-A-5-139053

Eyne S. Trumble P. S. & E. 7 213 (1963)

  The present invention has been made to solve the above problems, and the contrast between the printed portion and the non-printed portion is good, the stability of the image is excellent, the repeat resistance is excellent, and further, the specific color is An object of the present invention is to provide a display recording material suitable for color display by properly using magnetic powder fine particles.

The present invention has been made to achieve the above object,
The invention according to claim 1 of the present invention is
On a support made of a nonmagnetic material, a colored layer, an inorganic material layer containing an inorganic material having a high thermal conductivity, and an upper layer thereof, an organic low molecular weight material as a main component and its transparency is reversible depending on temperature. And a protective layer, and a reversible heat-sensitive layer which changes into the above, and a magnetic recording layer formed by dispersing and arranging microcapsules containing a magnetic powder and a dispersion medium in a binder on top of that.
The display recording medium is characterized in that the magnetic powder is a magnetic powder exhibiting a specific color, and the layer thickness of the reversible heat sensitive layer is 10 μm to 100 μm.

The invention of claim 2 according to the present invention is
The dispersion medium in the microcapsules is a substance showing a solid phase at normal temperature, and the temperature showing the liquid phase of the dispersion medium is lower than the temperature at which the reversible heat sensitive layer becomes cloudy, and the support It is a display recording material according to claim 1, characterized in that it is lower than the glass transition temperature.

The invention of claim 3 according to the present invention is
The display recording medium according to claim 1 or 2, wherein the magnetic powder exhibiting a specific color is a white magnetic powder.

The invention of claim 4 according to the present invention is
The particle size of the said magnetic powder is 5 micrometers-40 micrometers, It is a display recording material in any one of the said Claims 1-3 characterized by the above-mentioned.

According to the display and recording material of the present invention, it is possible to obtain a display and recording material which is excellent in the stability of the image, excellent in the repeated stability, and favorable for color display.
In particular, heat can be efficiently conducted by the proximity of the layer containing the inorganic material with high thermal conductivity and the reversible heat sensitive layer, and the optical change of the reversible heat sensitive layer can be realized at a relatively low temperature, so excessive heat It is possible to prevent repeated deterioration of the reversible thermosensitive layer due to

It is a schematic cross section of one Embodiment of the display recording body of this invention. It is a schematic cross section of one embodiment of the microcapsule used for a magnetic recording layer by this invention. It is explanatory drawing which shows the state and color development of the magnetic recording layer of this invention, and a reversible thermosensitive layer.

FIG. 1 is a view showing the constitution of an embodiment of the display recording material 1 of the present invention, wherein a colored layer 12 and an inorganic material layer 13 containing an inorganic material having high thermal conductivity are laminated on a support 11 On top of that, a reversible heat sensitive layer 14 having a resin matrix and an organic low molecular weight substance dispersed in the resin matrix is laminated, and further white magnetic powder (or magnetic powder having a specific color) etc. The magnetic recording layer 15 to which a coating material obtained by dispersing the microcapsules 2 including the above in a binder 16 is applied is sequentially laminated.

  The core material 22 is covered with a shell material 21 to form a capsule shape. The core material 22 contains a magnetic material, and for example, white magnetic powder is used. For example, a transparent resin or the like is used as the shell material 21.

FIG. 2 is a cross-sectional view showing an example of the microcapsule 2 containing white magnetic powder (or magnetic powder having a specific color) used for the magnetic recording layer 15 in one embodiment of the display recording material of the present invention. It is.
As shown in FIG. 2, in the microcapsules 2, white magnetic powder 23 is dispersed in a dispersion medium 24, and the periphery thereof is covered with a shell material 21 for encapsulation.

  The white magnetic powder 23 may be any fine particle which partially contains a magnetic material and looks white, and examples thereof include stainless steel such as iron, nickel, iron-nickel, iron-nickel-chrome, cobalt, What made particle | grains, such as cobalt aluminum, a samarium cobalt alloy, etc. as fine particles of powdery or flake shape with an atomizer, a hammer mill etc., can be whitened and used.

  The whitening treatment may be performed by coating the magnetic powder fine particles with metal, metal oxide, white inorganic compound, white crystalline organic compound or the like by various known wet or dry methods. For example, a plating method, a spray drying method, a vapor deposition method, etc. may be mentioned. Furthermore, in order to enhance the affinity of these white magnetic powders with organic solvents and the like, higher ester treatment, silane coupling treatment, titanate coupling treatment and the like may be performed.

In the present invention, the size of the white magnetic powder 23 is the thickness of the masking layer capable of concealing the magnetic powder in white, the ease of movement of the magnetic powder in the microcapsule by magnetic application, and the image contrast of the magnetic recording layer 15 In consideration of the above, the particle size is preferably 5 μm to 40 μm.
The magnetic powder having a specific color is the same as the white magnetic powder except that the color is not limited to white. The specific color may be any color, for example red, green or yellow.

The dispersion medium 24 is preferably a hydrophobic solvent or the like, but particularly preferably a high-boiling point solvent having low volatility at room temperature. In the case of a heat / magnetic recording medium, it is solid at normal temperature (in the range of about 10 to 35 ° C.) (in a solid state) and heated to a temperature above normal temperature (in the range of about 40 to 80 ° C.) Use one that becomes fluid (liquid phase state) when it is done.
For example, organic compounds which are generally known compounds satisfying the above conditions such as paraffin wax, natural or synthetic waxes such as carnauba wax, natural or synthetic resins, or carboxylic acid esters may be suitably used alone or in combination with a solvent or the like. Can. In addition, you may color in the range which does not prevent light transmittance.
By applying a magnetic field when the dispersion medium 24 becomes fluid, the orientation of the white magnetic powder 23 is changed, and then the dispersion medium 24 is solidified to fix the orientation of the white magnetic powder.

The core material 22 mainly composed of the above-described white magnetic powder 23 (or magnetic powder having a specific color), the dispersion medium 24 and the like is covered with a shell material 21 such as a polymer and microencapsulated. Examples of the resin used as the shell substance 21 include commonly used resins such as acrylic resins, methacrylic resins, polystyrenes, polyester resins, polyurethane resins, polyurea resins, polyamide resins, epoxy resins and natural resins. , These alone or 2
It is also possible to use a mixture of species or more.

  As a method for producing the microcapsules 2 having the above-mentioned shell substance, a phase separation method in which a concentrated phase of the polymer is separated around the core substance dispersed in the polymer solution, curing test of the polymer around the core substance in the polymer solution In-liquid curing method in which the polymer is cured by medicine etc., in-situ polymerization method in which the monomer and the polymerization catalyst are supplied from either one of the emulsion in which the core substance is dispersed or the outer phase and the surface of the core substance is covered with the polymer Microencapsulation techniques, such as interfacial polymerization, in which monomers are supplied from both the inner and outer phase of the emulsion in which the core material is dispersed are suitable, but are not limited to these methods.

  In particular, the in-situ polymerization method or the phase separation method in which the monomer is supplied from the external phase of the suspension in which white magnetic powder 23 (or magnetic powder exhibiting a specific color) which is core substance 22 is uniformly dispersed in dispersion medium 24 By manufacturing, it is possible to manufacture the microcapsule 2 having uniform particle diameter and easy movement of the white magnetic powder (or magnetic powder having a specific color) 23. As the polymerizable monomer to be used here, acrylic acid ester, methacrylic acid ester, styrene and derivatives thereof, isocyanate, various amines, compounds having an epoxy group, and the like are preferable.

  The particle size of the microcapsules 2 is preferably about 10 μm to 300 μm. When the particle size is 10 μm or less, the size of the magnetic powder contained in the capsule is small and the content is relatively small, so the concealing effect is weakened and the contrast is lowered. When the particle size is 300 μm or more, the thickness is too large, and it takes time to move the magnetic powder.

  As the binder 16 for dispersing the microcapsules 2 in the magnetic recording layer 15, a water-based binder, a solvent-based binder, an emulsion-based binder, etc. may be suitably used. In particular, when a curable resin is used, the friction resistance of the recording medium or It is preferable because the resistance to repetitive printing deletion is improved. The curable resin includes, for example, a photocurable resin such as UV curable resin and EB curable resin, a thermosetting resin having an isocyanate group, a melamine group, an epoxy group, etc., and a moisture curable resin, etc. Be

  The resin base material used for the reversible heat sensitive layer 14 provided under the magnetic recording layer 15 is a material that forms a layer in which the organic low molecular weight substance is uniformly dispersed and held, and affects the transparency at the maximum transparency. For this reason, the resin base material is preferably a resin having good transparency, mechanical stability, and good film forming property.

  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 united materials; polyvinylidene chloride-based copolymers such as polyvinylidene chloride, vinylidene chloride-vinyl chloride copolymer, vinylidene chloride-acrylonitrile copolymer; polyesters; polyamides; polyacrylates, polyacrylates or polymethacrylates or acrylates -Methacrylate copolymer; silicone resin etc. are mentioned. These are used individually or in mixture of 2 or more types. For example, vinyl chloride-vinyl acetate copolymer can be used.

On the other hand, as the organic low molecular weight substance, any substance which changes from polycrystal to single crystal by heat in the recording layer may be used. Generally, one having a melting point of 30 to 200 ° C, preferably about 50 to 150 ° C is used. Such organic low molecular weight substances include alkanols, alkanediols, halogen alkanols or halogen alkanediols, alkylamines, alkanes, alkenes, alkynes, halogen alkanes, halogen alkenes, halogen alkynes, cycloalkanes, cycloalkenes, cycloalkynes, saturated or 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; aryl carboxylic acids or their esters, amides or ammonium salts; halogen allyl carboxylic acids or Their esters, amides or ammonium salts; thioalcohols; thiocarboxylic acids or their esters, amines or ammonium salts; thioalcohols Carboxylic acid esters, and the like.

These are used individually or in mixture of 2 or more types. The carbon number of these compounds is preferably 10 to 60, more preferably 10 to 38, and particularly preferably 10 to 30. The alcohol moiety in the ester may be saturated or unsaturated, and may be halogen-substituted. Any case the oxygen in the organic low-molecular material is molecules also, nitrogen, at least one sulfur and halogens, for example -OH, -COOH, -CONH -, - COOR, -NH -, - NH 2, -S-, It is preferable that it is a compound containing -S-S-, -O-, a halogen etc.

  Furthermore, those obtained by adding a known additive, for example, an ultraviolet absorber, a solar absorber, a plasticizer, a lubricant, a colorant, an antioxidant, a flame retardant, etc., to these organic polymers are also available. It can be used.

  More specifically, as these compounds, lauric acid, dodecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, stearic acid, behenic acid, nonadecanoic acid, aralic acid, oleic acid, adipic acid, 1,4 cyclohexanedicarboxylic acid Higher fatty acids such as acids; ethers or thioethers such as esters of higher fatty acids such as methyl stearate, tetradecyl stearate, octadecyl stearate, octadecyl laurate, tetradecyl palmitate and dodecyl behenate; Among them, in the present invention, higher fatty acids, particularly higher fatty acids having 16 or more carbon atoms such as palmitic acid, stearic acid, behenic acid and lignoceric acid are preferable, and higher fatty acids having 16 to 24 carbon atoms are more preferable. For example, behenic acid, stearic acid, adipic acid, 1,4 cyclohexanedicarboxylic acid can be used.

The thickness of the reversible heat-sensitive layer 14 is preferably 10 μm to 100 μm, and more preferably 15 μm to 50 μm.
When the film thickness of the reverse heat sensitive layer 14 is smaller than 10 μm, the effect of making the color tone of the colored layer clouding weakens, and the difference in color tone between the case of clouding and the case of transparency becomes smaller I will. Moreover, when it is larger than 100 μm, when it is made transparent, the transparency is deteriorated, and the color development of the colored layer becomes weak. In addition, the white color when whitened becomes cloudy and becomes milky white which is yellowish, and the color taste is impaired.

In the present invention, a colored layer 12 and an inorganic material layer 13 containing an inorganic material having high thermal conductivity are laminated on a support 11, and a resin matrix and an organic low molecular weight substance dispersed in the resin matrix are provided thereon. It is characterized in that a reversible heat sensitive layer 14 is laminated.
That is, by the fact that the inorganic material layer 13 containing the inorganic material having high thermal conductivity and the reversible heat sensitive layer 14 are in the vicinity, when heat is applied to the reversible heat sensitive layer, the heat is reversibly heat efficiently from the heat source. It is possible to transfer to the layer and to realize the optical change of the reversible thermosensitive layer at relatively low temperature without the need of excessive heat. Therefore, it is possible to prevent repeated deterioration of the reversible heat sensitive layer due to excessive heat.

  Inorganic materials with high thermal conductivity include metal oxides such as aluminum oxide, magnesium oxide, zinc oxide and silicon oxide, clay minerals such as calcium carbonate, talc and mica, and metals such as aluminum nitride, boron nitride and silicon nitride It is possible to use nitrides, metals such as copper, aluminum, nickel and silver, and other powders or fibers such as silicon carbide, carbon, graphite and diamond. When the inorganic material layer is colored, the inorganic material layer may be used also as a colored layer.

In the present invention, the temperature at which the dispersion medium 24 of the magnetic powder 23 in the microcapsule 2 exhibits a liquid phase state is more preferably lower than the temperature at which the reversible thermosensitive layer 14 becomes cloudy.
In this case, the reversible thermosensitive layer 14 becomes transparent by heating in a temperature range higher than the normal temperature, and the transparent state is maintained even when cooled to the normal temperature in this state. Furthermore, when the temperature is raised to a temperature higher than the temperature range to be clarified, it becomes a white turbid state, and even when returned to normal temperature, the white turbid state is maintained without becoming transparent.

  On the other hand, when the temperature at which the dispersion medium in the microcapsule 2 shows a liquefied state is equal to or higher than the clouding temperature of the reversible heat sensitive layer 14, in order to liquefy the dispersion medium to move the magnetic powder in the microcapsule 2 The heating temperature must be above the clouding temperature, which may make it impossible to control the magnetic powder in the state in which the reversible heat-sensitive layer 14 is made transparent.

  As the coloring component of the coloring layer 12, a single pigment, a mixture of several pigments, a mixture of a pigment and a polymer, a single dye, a mixture of several dyes, and the like can be used. For example, pigments are generally known: inorganic pigments such as titanium dioxide, zinc sulfide, lead titanate, zirconium oxide, lead white, cadmium red, cadmium yellow, etc., fine particles of organic pigments such as phthalocyanine pigments, and dyes are azo dyes Known various pigments and dyes such as quinoline dyes and phthalocyanine dyes are used.

When using a pigment or a mixture of a pigment and a polymer, the above pigment or the pigment and the polymer are kneaded and then pulverized, or a pigment or a monomer in which the pigment is dispersed is subjected to emulsion polymerization, suspension polymerization, dispersion polymerization A method such as polymerization is used using a method such as In this case, the polymer is preferably crosslinkable.
As the binder for dispersing and dissolving these pigments or dyes, a water based binder, a solvent based binder, an emulsion based binder and the like are used. Moreover, it is also possible to select a plurality of colors to be printed and express them simultaneously by patterning.

  The support 11 is made of a nonmagnetic material, and for example, polyvinyl chloride, polyester, polycarbonate, polymethyl methacrylate, polystyrene, polyethylene, synthetic resin such as polyethylene terephthalate, natural resin, paper, synthetic paper, metal, ceramic, etc. alone or in combination Can be used as a complex. The shape can also be selected according to the application, such as card-like, sheet-like or film-like, and in view of the physical properties required according to the application, such as strength, rigidity, hiding property, light impermeability, etc. It can be selected appropriately.

When the support 11 is a resin, it is preferable that the glass transition temperature (Tg) of the resin is higher than the transparency temperature of the reversible heat-sensitive layer 14 and the melting temperature of the dispersion medium 24.
For example, as the Tg of the resin used for the support 11, a resin having a temperature of about 35 to 70 ° C. or about 87 to 300 ° C. is selected. Further, the support used in the examples described later also has a Tg of about 70.degree.
With this configuration, the white magnetic material of the dispersion medium 24 can be oriented at a temperature lower than the Tg of the support 11, so that the deterioration of the support 11 can be suppressed more than in the prior art.
In addition, although it is preferable that the transparentization temperature of the reversible thermosensitive layer 14 is lower than Tg, it can be designed according to the objective.

The protective layer 17 protects the microcapsules 2 and the reversible heat-sensitive layer 14 formed on the support 11, and the white magnetic powder (or magnetic powder having a specific color) 23 in the microcapsule 2 can be seen from the outside. It is necessary to have such light transparency. As such a protective layer 17, various known materials such as various polymer resins and films can be used as long as they have transparency. For example, synthetic resins such as epoxy resin, tetrafluoroethylene, polyvinyl chloride, polyester, polycarbonate, polymethyl methacrylate, polystyrene, etc., natural resins, and films of nylon, polyethylene terephthalate, polyimide etc. can be used. In particular, polyethylene terephthalate film, polyethylene naphthalate film and the like are preferable. Furthermore, the protective layer 17 may be provided between the inorganic material layer 13 and the reversible heat sensitive layer 14 or between the reversible heat sensitive layer 14 and the magnetic recording layer 15.

When using the display recording material of the present invention, heating from the protective layer 17 side will be described as an example. Heat penetrates from the protective layer 17 toward the support 11. At this time, if the inorganic material layer 13 is not present, the heat does not reach the reversible thermosensitive layer 14, so the heating temperature is high. There is a need to.
On the other hand, when the inorganic material layer 13 is provided as in the present invention, heat easily penetrates to the support 11 side, and the heat can reach the reversible thermosensitive layer 14 even if the heating temperature is low. Therefore, heat is easily transmitted to the dispersion medium 24 in the microcapsules 2 of the magnetic recording layer 15 and the reversible heat sensitive layer 14 existing between the protective layer 17 and the support 11, and the display recording material 1 itself It is possible to extend the life (suppress the deterioration of the display recording material 1).
Further, by providing the inorganic material layer 13, the heat is uniformly transmitted to the direction orthogonal to the heat penetration direction, that is, the entire inorganic material layer 13, so the display of the display recording medium 1 can be changed earlier than before. It becomes possible.

  The colored layer 12, the inorganic material layer 13, the reversible heat-sensitive layer 14, the magnetic recording layer 15, and the protective layer 17 may be formed by, for example, a known printing method such as offset printing, gravure printing or silk screen printing Roll coating method, coating method such as knife edge method, transfer method using a transfer sheet, ink jet method of spraying ink on a substrate, etc. It can be manufactured according to the use of the information recording medium to be manufactured and quantity It is possible to select one of the methods described above. The inorganic material layer 13 can also be formed by a thin film forming technique such as a sputtering method or a vapor deposition method, in addition to the above-described manufacturing method.

Next, a method of forming a display image on the display recording material of the present invention will be described.
FIG. 3 shows a cross-sectional view of the display recording material and the display color.

In FIG. 3A, the reversible heat-sensitive layer 14 is whitened, and the white magnetic powder (or magnetic powder of a specific color) 23 in the microcapsule 2 is aligned and oriented parallel to the magnetic recording layer 15. FIG.
The white magnetic powder (or magnetic powder of a specific color) 23 in the microcapsule 2 is oriented so as to be continuous in the parallel direction by the magnetism of the magnetic recording layer 15 uniformly applied in the parallel direction to the support 11. Thus, the surface of the display recording medium has a uniform white tone (or the color of magnetic powder of a specific color) in which most of incident light is reflected by the white magnetic powder (or magnetic powder of a specific color).

  Here, in order to efficiently align white magnetic powder (or magnetic powder of a specific color) in a planar manner, for example, a method of arranging magnets on all the side surfaces of the display recording material, magnets on the side surfaces of the display recording material There are a method of rotating the display recording body after placement, a method of rotating a magnet around the side surface of the display recording body, and the like.

  FIG. 3B shows a state in which the reversible heat-sensitive layer 14 is whitened and oriented such that white magnetic powder (or magnetic powder of a specific color) 23 is aligned in a direction perpendicular to the magnetic recording layer 15. FIG. For example, by arranging magnets vertically in the vertical direction, the white magnetic powder (or magnetic powder of a specific color) 23 in the microcapsules 2 of the magnetic recording layer 15 is oriented so as to be continuous with the magnetic recording layer 15. . As a result, the incident light is hardly reflected in the incident direction by the white magnetic powder (or magnetic powder of a specific color) 23, so that the whitened colored layer or the white layer overlapped with the whitened reversible heat sensitive layer. It becomes the color tone of a polished inorganic material layer.

  FIG. 3C shows that the reversible heat sensitive layer 14 is made transparent, and the white magnetic powder (or the magnetic powder of a specific color) 23 in the microcapsule 2 is aligned and oriented parallel to the magnetic recording layer 15. FIG. Since the white magnetic powder (or magnetic powder of a specific color) 23 is arranged in a parallel direction, the white magnetic powder (or magnetic powder of a specific color) 24 reflects white light by reflection of incident light. Powder color is displayed.

  FIG. 3D is an explanatory view showing a state in which the reversible heat-sensitive layer 14 is made transparent, and the white magnetic powder 23 is aligned and oriented in a direction perpendicular to the magnetic recording layer 15. The reversible thermosensitive layer 14 is transparent, and is hardly reflected by the white magnetic powder 23 in the incident direction, so that the hue of the colored layer 12 or the inorganic material layer is displayed.

  Since this image formation utilizes magnetism, recording is easy, and by controlling the particle size of the microcapsules 2, high-resolution image formation is possible. When white magnetic powder is used in particular, the whiteness of the reversible heat-sensitive layer and the white color when horizontally oriented overlap with each other, so that the whitening property is more excellent and the contrast is good. In addition, a bright color can be expressed without darkening the color of the underlying colored layer at the time of vertical alignment.

  Recording information by making the orientation state of the white magnetic powder (or magnetic powder of a specific color) 23 relative to the magnetic recording layer 15 be based on either the parallel direction or the vertical direction and partially the other. In contrast to the above, based on the white magnetic powder (or magnetic powder having a specific color) in the vertical direction as the base, the alignment state is changed partially in the parallel direction to make visible display information Recording may be performed.

The microcapsules 2 used here can be formed into a coating by mixing and coating with a binder, so that they can be coated on various supports and can be processed into various shapes. Because the manufacturing process is simple, the range of applications can be expanded.
In particular, when it is coated on paper, it can be used as an information recording sheet such as a home-use fax machine, and printing and erasing can be easily and reversibly performed by application of heat and magnetism, so that it can be used as recycled paper.

  Hereinafter, the present invention will be described more specifically based on examples.

Example 1
"Preparation of reversible heat sensitive layer coating liquid"
Resin base material: 30 parts of Solvain A (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.9 parts of Duranate 24A-100 (manufactured by Asahi Kasei Corporation), 6 parts of behenic acid as an organic low molecular weight material, 1 part of stearic acid, 2.5 adipic acid A reversible heat sensitive layer coating solution was prepared by diluting and mixing 0.5 parts of 1,4 cyclohexanedicarboxylic acid with 155 parts of tetrahydrofuran and 39 parts of toluene.

"Preparation of coating solution for magnetic recording layer"
Using a hybridizer, magnetic powder particles (iron-nickel alloy) having an average particle diameter of 15 μm were coated with titanium dioxide particles having an average particle diameter of 1.5 μm to prepare white magnetic powder. Next, the white magnetic powder was subjected to silane coupling treatment. 30 parts of this white fine particle and 70 parts of dodecylbenzene were mixed well, and this was dispersed in 4000 parts by weight of 10% aqueous gelatin solution for about 5 minutes so as to have an average particle diameter of 75 μm at 2000 rpm using a homogenizer . 400 parts by weight of a 10% aqueous solution of gum arabic was mixed with the obtained dispersion, and 1000 parts by weight of water was further added, kept at 40 ° C., and a 10% aqueous acetic acid solution was dropped to adjust the pH to 4. Thereafter, the solution temperature was cooled to 5 ° C., 10 parts by weight of a 30% formalin aqueous solution was added, and a 10% aqueous sodium hydroxide solution was added dropwise to adjust the pH to 9 to prepare microcapsules of gelatin-gum arabic wall. The microcapsules were filtered, and then dispersed as a binder 16 in an aqueous emulsion type UV curable resin solution to obtain a coating solution for a magnetic recording layer.

"Production of display record"
A black layer (colored layer) composed of carbon black and a urethane resin was provided as a colored layer on a 100 μm-thick biaxially stretched polyethylene terephthalate (PET: Tg 69 ° C.) sheet as a support. Silver particles dispersed in toluene are coated and dried on this, a 50 nm thick inorganic material layer is provided, and the above-mentioned reversible heat sensitive layer coating liquid is coated and heated on this, and a 20 μm thick reversible heat sensitive layer is provided. The coating solution for the magnetic recording layer was applied and dried thereon, and UV irradiation was performed to provide a magnetic recording layer with a thickness of 90 μm. Furthermore, a UV curable resin (containing a lubricant filler) was applied thereon, and then cured by UV irradiation to provide a protective layer of 20 μm.

"Recording an image"
A magnetic field was applied horizontally to the magnetic recording layer to put the entire display recording body in an entirely erased state. Next, the display recording medium was heated to an arbitrary temperature using a thermal gradient tester (manufactured by TP-701C, manufactured by Tester Sangyo Co., Ltd.) to make the reversible heat-sensitive layer white and transparent. Further, the printing was performed by applying a magnetic field to a part vertically, and the magnetic powder in the microcapsules of the pattern portion was vertically oriented to make a recording state.

Example 2
"Preparation of reversible heat sensitive layer coating liquid"
In the same manner as in Example 1, a reversible heat-sensitive layer coating solution was prepared.

"Preparation of coating solution for magnetic recording layer"
Silver was sputtered into 60 parts by weight of iron-cobalt-nickel alloy to make a white magnetic powder, which was subjected to oleic acid treatment. Next, this is uniformly dispersed in 100 parts by weight of a mixed solvent of paraffin wax and dibutyl phthalate which is heated to 50 ° C. and melted, and the dispersion is homogenized in 300 parts by weight of 5% polyvinyl alcohol heated to 50 ° C. The mixture was dispersed for about 5 minutes so as to have an average particle diameter of 100 .mu.m at a rotation number of 2500 rpm.
To the resulting dispersion, 100 parts by weight of a melamine-formalin prepolymer aqueous solution was added, and a 20% aqueous acetic acid solution was added dropwise to adjust the pH to 6. Thereafter, the liquid temperature was raised to 65 ° C., and a polymerization reaction was carried out for 30 minutes to prepare microcapsules of melamine-formalin wall. The capsule was mixed with an acrylic emulsion resin and an epoxy curing agent as a binder to prepare a coating solution for the magnetic recording layer.

"Production of display record"
A mixed solution of a phthalocyanine pigment and an aqueous acrylic emulsion was applied as a cyan colored layer on a biaxially stretched polyethylene terephthalate (PET) sheet having a thickness of 100 μm as a support. Next, aluminum was attached by vapor deposition to form a 20 nm thick inorganic material layer. The reversible heat sensitive layer coating liquid was applied and heated thereon, and a 30 μm thick reversible heat sensitive layer was provided. The magnetic recording layer coating solution was applied thereon, dried, and thermally cured at 120 ° C. for 10 minutes to obtain a 50 μm magnetic recording layer. Furthermore, a UV curable resin (containing a lubricant filler) was applied thereon, and then cured by UV irradiation to provide a protective layer of 20 μm.

"Recording an image"
The display recording medium was heated to 80 ° C., and a magnetic field was applied horizontally to the magnetic recording layer to align the white magnetic powder horizontally in a plane and orientate it, resulting in the entire erased state. Next, the display recording medium was heated to an arbitrary temperature using a thermal gradient tester (manufactured by TP-701C, manufactured by Tester Sangyo Co., Ltd.) to make the reversible heat-sensitive layer opaque and transparent. Next, in a state where a magnetic field is applied perpendicularly to the magnetic recording layer, printing is performed with a thermal head in accordance with the pattern of visible display information to be recorded, and the magnetic powder in the microcapsules of the pattern portion is vertically aligned. It orientated and set it as the recording state.

Comparative Example 1
A display recording medium was prepared and evaluated in the same manner as in Example 1 except that the reversible heat-sensitive layer was coated to a thickness of 5 μm.

Comparative Example 2
A display recording medium was prepared and evaluated in the same manner as in Example 1 except that the reversible heat-sensitive layer was applied to a thickness of 110 μm.

Comparative Example 3
In the same manner as in Example 2 except that ceresin wax (liquefaction temperature: 95 ° C.) was used instead of paraffin wax (Example 2) as the dispersion medium for the magnetic powder contained in the microcapsules in the magnetic recording layer, Were evaluated and evaluated.

Comparative Example 4
A display recording material was prepared and evaluated in the same manner as in Example 2 except that the inorganic material layer was not provided and the reversible heat-sensitive layer was provided directly on the colored layer.

<Evaluation>
The display recording materials obtained in Examples 1 and 2 and Comparative Examples 1 to 4 were evaluated by the following four methods. The results are shown in Table 1 below.

(Optical reflection density: OD value)
The OD value (optical density) of the portion (a) in which the reversible heat-sensitive layer of the obtained display recording material is clouded and the magnetic powder contained in the microcapsule in the magnetic recording layer is oriented parallel to the magnetic recording layer, The OD value of the portion (b) in which the reversible heat sensitive layer is made transparent and the magnetic powder contained in the microcapsule in the magnetic recording layer is oriented perpendicularly to the magnetic recording layer is measured with a Macbeth densitometer (RD-918S), Compared.

(Color tone)
The reversible heat-sensitive layer of the obtained display recording material is whitened, and the color tone of the portion (c) in which the magnetic powder contained in the microcapsule in the magnetic recording layer is oriented perpendicularly to the magnetic recording layer is the reversible heat-sensitive layer. A portion (a) is whitened and the magnetic powder contained in the microcapsule in the magnetic recording layer is oriented parallel to the magnetic recording layer, and the reversible heat sensitive layer is made transparent, and the magnetic material contained in the microcapsule in the magnetic recording layer The powder was visually compared with the color tone of the portion (b) oriented perpendicularly to the magnetic recording layer.

(Measurement of clouding temperature range of reversible thermosensitive layer)
A thermal gradient tester (from the opposite side of the support) with the reversible thermosensitive layer of the display recording material obtained made transparent and the magnetic powder contained in the microcapsules in the magnetic recording layer being oriented perpendicularly to the magnetic recording layer The temperature was changed from 50 ° C. to 100 ° C. and heated using TP-701C (manufactured by Tester Sangyo Co., Ltd.), and the change in color tone of the display recording material was visually evaluated. The judgment criteria are shown below.
○: The color of the colored layer can be observed. ×: The reversible heat sensitive layer is clouded and the color of the whitened colored layer can be observed.

(Print erase conversion)
The easiness of the printing erasure conversion of the obtained display recording material was evaluated. The judgment criteria are shown below.
○: The conversion process is simple ×: The conversion process is complicated

In Examples 1 and 2, the difference between the OD value of the a part and the OD value of the b part was large and the contrast was good, and the color tone of the c part was a middle color between the a part and the b part. In addition, the clouding temperature of the reversible heat sensitive layer was also a low value.
However, in Comparative Examples 1 and 2, the difference between the OD value of part a and the OD value of part b was small, and the contrast was inferior to Examples 1 and 2. The c part of Comparative Example 1 had substantially the same color as the b part, and the c part of Comparative Example 2 had a milky-white reversible thermosensitive layer and a cloudy neutral color. This is because the thickness of the reversible heat sensitive layer is as thin as 5 μm in Comparative Example 1 and as thick as 110 μm in Comparative Example 2.
Comparative Example 3 has good contrast and color tone of part c, but the liquefying temperature of the dispersion medium in the microcapsule is equal to or higher than the clouding temperature of the reversible heat sensitive layer, so the reversible heat sensitive layer and the magnetic recording layer are simultaneously After the magnetic powder of the magnetic recording layer was oriented, the reversible heat sensitive layer had to be made transparent, which made the conversion process complicated.
In addition, in Comparative Example 4 in which the inorganic material layer is not provided, the clouding temperature of the reversible heat sensitive layer is 90 ° C., which is a higher value than in Examples 1 and 2, and excessive heating causes clouding of the reversible heat sensitive layer. It became necessary.

1 ··· Display record
11 ・ ・ ・ Support
12: Colored layer 13: Inorganic material layer 14: Reversible heat sensitive layer 15: Magnetic recording layer 16: Binder 17: Protective layer 2: Microcapsule 21: Shell material 22 core material 23 white magnetic powder (or magnetic powder having a specific color)
24 ・ ・ ・ Dispersion medium

Claims (4)

On a support made of a nonmagnetic material, a colored layer, an inorganic material layer containing an inorganic material having a high thermal conductivity, and an upper layer thereof, an organic low molecular weight material as a main component and its transparency is reversible depending on temperature. And a protective layer, and a reversible heat-sensitive layer which changes into the above, and a magnetic recording layer formed by dispersing and arranging microcapsules containing a magnetic powder and a dispersion medium in a binder on top of that.
A display recording medium, wherein the magnetic powder is a magnetic powder exhibiting a specific color, and the layer thickness of the reversible heat sensitive layer is 10 μm to 100 μm.   The dispersion medium in the microcapsules is a substance showing a solid phase at normal temperature, and the temperature showing the liquid phase of the dispersion medium is lower than the temperature at which the reversible heat sensitive layer becomes cloudy, and the support The display recording material according to claim 1, which is lower than the glass transition temperature.   The display recording medium according to claim 1 or 2, wherein the magnetic powder exhibiting a specific color is a white magnetic powder.   The display recording material according to any one of claims 1 to 3, wherein the particle size of the magnetic powder is 5 m to 40 m.