JPH091963A - Transfer foil capable of reversibly displaying and recording medium capable of reversibly displaying - Google Patents

Abstract

PURPOSE: To obtain a display unit having reliability and securability impossible to easily alter the display in a natural environment or for the purpose of falsification and capable of reversibly displaying with flat and small step. CONSTITUTION: This transfer foil comprises a reversibly display layer 3 made at least of a liquid crystal and polymer composite film and reversibly varying in optical transmittance and absorbance by heat and electric field at least on a releasable support 2, and an adhesion layer 4 sequentially laminated. Further, a protective layer 5, a primer layer 7, a reversible display layer, a barrier layer 8, a conductive layer 6 and an adhesion layer are sequentially laminated on the releasable support. The conductive layer is formed of a metal thin film, a metal foil, and a conductive resin layer, the polymer of the liquid crystal and polymer composite film is formed of a water soluble polymer, the barrier layer is formed of a water soluble polymer, and the adhesion layer is formed of an adhesive of an aqueous emulsion or aqueous soluble polymer. If the sheet resistance of the coating material is 10<12> Ω/sq or less, the conductive layer may be omitted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer foil capable of reversibly displaying visible information using a reversible display material composed of a liquid crystal / polymer composite film as a reversible display layer, and an information recording medium of invisible information (for example, magnetic recording medium). Card, IC card, non-contact IC card, etc.) to which the transfer function is transferred to provide a display function,
Alternatively, the present invention relates to a reversible display recording medium such as a simple display card.

[0002]

2. Description of the Related Art Various information recording media such as point cards, magnetic cards, IC cards, and non-contact IC cards are in widespread use. Usually, these have an information recording section for recording information in an invisible state. It usually does not have a display function that can rewrite and display visible information. Therefore, an irreversible display means by leuco color development or thermal destruction of a metal thin film has been put into practical use for the purpose of adding a display function that can be recorded afterwards, instead of in advance by print display or the like. However, if the recording medium is used for a short period of time, or if the display amount is small, the above irreversible display function is sufficient, but if the use period is long, or if it is recycled, the display amount is limited. It is not possible to deal with the fact that the unnecessary display cannot be deleted. For this reason,
A display function capable of reversibly recording and displaying has been desired. For example, it is an application for displaying a balance or the like recorded in an information recording medium such as a magnetic card or an IC card. Further, as a use of the recording medium for a long period of use (durability), there is a non-contact IC card type commuter pass or the like, and the recording medium can be recycled if the display that is no longer needed can be rewritten.

Therefore, various reversible display materials capable of rewriting display by external energy have been proposed as materials capable of realizing a display function capable of reversible display. Such a reversible display material utilizes heat, light, magnetism, etc. for recording and erasing the display. For example, a polymer / fatty acid dispersion film in which a fatty acid is dispersed in a polymer matrix and the fatty acid undergoes a phase change to make it cloudy or transparent, and the reversible opening and closing of the lactone ring of the leuco dye by a coloring / reducing agent is used. There are a liquid crystal display device and a liquid crystal display device using a polymer liquid crystal. Alternatively, there is a magnetic powder microcapsulated.

[0004]

If the reversible display material is formed on the base material such as the card by means such as printing or coating, it is possible to provide a rewritable display portion capable of reversible display. However, in order to provide a rewritable display portion on a recording medium such as a magnetic card, it is difficult to form it directly on the card substrate by means of printing, coating, etc. depending on the shape of the molded body and the shape of the recording medium, or In the case of direct forming, there are some cases where the product yield decreases. Further, the display means cannot be provided in a part of the recording medium by the coating means or the like. In particular, the position where the display portion is provided should be avoided so that the contact terminals of the IC card, the stripe portion of the magnetic card, etc. do not hinder the recording and reproduction of information, and it is possible to partially form the rewriting display portion at a desired position. This is an important issue for both practical and practical use.

Therefore, if a reversible display material can be formed in advance on a resin film or sheet in the form of an adhesive label, a label having a predetermined size can be attached to a desired position by cutting or the like, and thereby the rewriting display portion can be formed. Partial formation is possible. By the way, the applicant has already filed Japanese Patent Application No. 7-9594.
Label No. 0 has already been proposed. However, the label requires a support such as a film, and when the label is attached, the swelling of the display becomes large due to the thickness of the support, which causes a step around the display. Due to this step, when the rewriting means is brought into contact with the display section for rewriting, there is a problem that the step is damaged or is easily peeled off during carrying.

On the other hand, in addition to the simple display function, the display contents of the display section can be rewritten, but there are also applications in which something that cannot be easily tampered with is required to prevent forgery. For example, when displaying the contents of identification,
Security is also required in such applications. However, since the various reversible display materials described above can rewrite the display relatively easily, there is no problem as a simple means for confirming the recorded contents of invisible information, but there is a problem in terms of display security. For example, microencapsulation of soft magnetic powder easily changes the display at several hundred Oe, and is for confirmation only and has no security. Also, polymer /
A fatty acid film, a leuco dye, a polymer liquid crystal, and the like similarly have a problem that the display can be easily changed because they are simply rewritten only by heat and the security is low.
In addition, there is a problem in display reliability that the display disappears in a natural environment when only heat is used.

Therefore, it is an object of the present invention to partially and partially reduce the level difference in the display portion having security and reliability in which the display can be rewritten, but the display cannot be easily changed under the purpose of falsification or in a natural environment. It is an object of the present invention to provide a reversible display transfer foil which can be provided flat and a reversible display recording medium to which the transfer foil is transferred.

[0008]

In order to achieve the above object, the first invention of the reversible display transfer foil of the present invention comprises at least a liquid crystal / polymer composite film on a peelable support. A reversible display layer whose light transmittance or absorbance reversibly changes due to heat and an electric field and an adhesive layer are sequentially laminated. Further, a second invention of the present transfer foil is such that, in the above transfer foil, a protective layer is provided between the peelable support and the reversible display layer. Further, a third invention of the present transfer foil is such that each of the above transfer foils has a conductive layer between the reversible display layer and the adhesive layer. A fourth invention of the transfer foil is the transfer foil of the third invention, wherein the conductive layer is a metal thin film,
The structure is made of either a metal foil or a conductive resin layer.
The fifth invention of the transfer foil is the reversible display layer according to the third or fourth invention, wherein the polymer of the liquid crystal / polymer composite film constituting the reversible display layer is a water-soluble polymer. A barrier layer is provided between the insulating layer and the conductive layer. A sixth invention of the present transfer foil is the transfer foil of the fifth invention, wherein the barrier layer is made of a water-soluble polymer. A seventh invention of the transfer foil is the fifth or sixth invention.
In the transfer foil of the present invention, the adhesive layer is formed of an aqueous emulsion or an adhesive of a water-soluble polymer.

Next, a first invention of a reversibly displayable recording medium of the present invention is to transfer the transfer foil of the first or second invention to an adherend having an area resistance of 10 ¹² Ω / sq or less. The structure is formed. A second invention of a reversibly displayable recording medium of the present invention is to transfer the transfer foil of any one of the third to seventh inventions to an adherend having an area resistance of 10 ¹² Ω / sq or more. It will be configured.

The reversibly displayable transfer foil of the present invention and the recording medium on which the transfer foil is transferred will be described in more detail with reference to the drawings.

The layer structure of the transfer foil 1 capable of reversible display according to the present invention comprises, in FIG. 1, at least a releasable support 2 and a liquid crystal / polymer composite film, and the light transmittance or It comprises a reversible display layer 3 whose absorbance changes and an adhesive layer 4. If the adherend to which the transfer foil is transferred has an appropriate conductivity (for example, metal), that is, the conductivity is such that the electric field can be applied to the reversible display layer in the vertical direction from the adherend through the adhesive layer to change the display. The conductive layer is not necessary in the most basic layer structure if it has the property. However, since the conductive layer can be freely applied to an insulative adherend such as a plastic card, a conductive layer is interposed between the reversible display layer 3 and the adhesive layer 4, and the reversible display layer 3 becomes the outermost layer after transfer. 1 is a desirable mode in which a protective layer is provided on the reversible display layer for the purpose of protecting the film from scratches (after transfer). That is, in the reversible display transfer foil 1 of the present invention shown in FIG.
A protective layer 5, a reversible display layer 3, a conductive layer 6, and an adhesive layer 4 are sequentially laminated on the peelable support 2 (lower side in the drawing). The conductive layer may be laminated on and under the reversible display layer in that a vertical electric field is applied to the reversible display layer, but it is possible to apply an electric field to an arbitrary portion (after transfer).
Only the conductive layer on the back side is desirable. An external electrode or the like may be used on the front surface side.

In addition, FIG. 2 is different from the structure of FIG. 1 in that the intermediate layer 7 is replaced by the protective layer 5 in order to further improve the interlayer adhesion.
Between the reversible display layer 3 and the reversible display layer 3 to improve the adhesion between the two layers, and a conductive layer or the like provided on the reversible display layer 3 by providing the barrier layer 8 between the reversible display layer 3 and the conductive layer 6. This is a structure for preventing the reversible display layer 4 from being damaged during the formation of.

Next, each layer will be described in order from the main reversible display layer.

First, as the reversible display layer, for example, rewriting can be performed only by heat (heat-heat mode), a polymer / fatty acid dispersion film, a leuco dye, a polymer liquid crystal, or Microcapsules of magnetic powder that can be rewritten only by magnetism can be used, but those that can satisfy the requirements for security that makes it difficult to tamper with the display and reliability that the display does not easily disappear even in the natural environment As an example, a liquid crystal / polymer composite film, which is a reversible display element that requires both heat and an electric field for rewriting, is excellent. In the reversible display layer of the transfer foil of the present invention, this liquid crystal / polymer composite film, which is excellent in security and reliability among various reversible display elements, is used.

The liquid crystal / polymer composite film is a dispersion of smectic liquid crystal or the like in a polymer matrix, and is also known as PDLC (Polymer Dispersed Liquid Crystal).
Also called a film (hereinafter, liquid crystal / polymer composite film is referred to as PDLC
Membrane).

To explain the recording / erasing principle of the display of the reversible display layer by the PDLC film, the order change of the liquid crystal molecule alignment due to heat and electric field (thermo-electric field mode) (regular alignment such as homeotropic alignment or homogeneous alignment). State and
Light scattering and light transmission (change of light absorption amount of dichroic dye when combined with dichroic dye when guest-host effect is used) due to change of random alignment state and irregular alignment state) are used. Therefore, when white turbidity (light scattering) is used in the recorded state and transparent (light transmission) is used in the erased state, printing is performed with a thermal head capable of spot heating, and erasing is performed with PDLC.
For example, the film is sandwiched between electrodes.

Compared with other reversible display elements in the thermo-thermal mode, the PDLC film has a μ in the ordered alignment state by applying an electric field.
High-speed rewriting processing is possible due to the sec order and high speed, the number of rewritable times is sufficient, visibility is good with the combined use of dichroic dyes, and high electric field strength is required for rewriting, so tampering is not easy and It shows various excellent practical performances such as the display is hard to disappear in the environment and the display reliability is high.

For the PDLC film, for example, Japanese Patent Laid-Open No. 4-718 is used.
Although the one proposed by Japanese Patent Laid-Open No. 99 etc. can be used, among them, the microcapsulated liquid crystal is excellent in various points such as no exudation of the liquid crystal because the liquid crystal is completely surrounded by the mylocap capsule. Japanese Patent Application Laid-Open No. 5-30
1489, Japanese Patent Application No. 6-33283, Japanese Patent Application No. 6-
Those proposed in No. 44735 and Japanese Patent Application No. 6-119702 can also be used.

The polymer matrix for holding the liquid crystal dispersed in the PDLC film includes, for example, vinyl chloride resin, vinyl chloride resin such as vinyl chloride-vinyl acetate copolymer, vinylidene chloride resin, polymethacrylate, acrylate-
Acrylic resins such as methacrylate copolymers, polyvinyl alcohol resins, polycarbonate resins, polyester resins, epoxy resins, polyamide resins, polyutalene resins, polythiol resins, ionizing radiation curable resins that cure with ultraviolet rays or electron beams. Etc. are used.

Examples of liquid crystals include smectic liquid crystals, nematic liquid crystals, cholesteric liquid crystals, discholesteric liquid crystals, polymer liquid crystals, and mixed systems thereof. An appropriate amount of a dichroic dye can be mixed with the liquid crystal to increase the display contrast and enhance the visibility by the guest-host effect.

The method of dispersing the liquid crystal in the polymer matrix includes a phase separation method, an emulsion method, a microcapsule method, a solvent evaporation method, a suspension polymerization method and the like.

The PDLC film is usually used with a film thickness of about 3 to 23 μm. The lower limit is determined from the point of display contrast, and the upper limit is determined from the point of a practical drive voltage for the liquid crystal in a regular alignment state.

Next, as the releasable support 2, a polyester resin such as polyethylene terephthalate, a polyvinyl chloride resin, a polyolefin resin such as polypropylene, a cellulose resin, an acrylic resin or the like having a thickness of 10 to 10 can be used. A film of about 50 μm is used. In order that the layer directly formed on the peelable support 2, such as the protective layer 5 or the reversible display layer 3 can be easily peeled from the peelable support at the time of transfer, the peelable support 2 has the above-mentioned structure. Instead of using the synthetic resin film alone, an appropriate peeling treatment may be performed by forming a peeling layer on the film. As the release layer, for example, a release agent such as wax or silicone is used alone, or a thermosetting resin such as an acrylic resin or a mixture of thermosetting resins is applied or formed, or an acrylic resin, a melamine resin, or the like. The thermoplastic resin, the thermosetting resin, or the like is applied and formed.

The adhesive layer 4 is a layer which becomes a heat-sensitive adhesive layer that exhibits adhesiveness by heat, and a thermoplastic resin having an affinity for the adherend to be the transfer surface is appropriately selected and used. Examples of the thermoplastic resin include known thermoplastic resins for transfer foils such as acrylic resins and styrene resins.
The adhesive layer may be formed by applying a thermoplastic resin coating liquid, but if an organic solvent is used for the coating liquid, the solvent during coating may adversely affect the alignment of the liquid crystal in the reversible display layer. It is preferable to form a coating liquid mainly containing, and it is preferable to form from a water-based emulsion adhesive or a water-soluble polymer adhesive. Therefore, the thermoplastic resin used to form the adhesive layer may be used as an adhesive for an aqueous emulsion, for example, a polyester resin, a urethane resin, an acrylic resin, a vinyl acetate resin, or an adhesive for a water-soluble polymer. Examples thereof include polyvinyl alcohol and cellulose derivatives that can be used as agents. If the conductive layer is already formed and the conductive layer is a metal thin film or the like and is completely impermeable to the solvent without any small pores, a resin using an organic solvent-based coating liquid is used. The components are also relatively easy to use. The thickness of the adhesive layer is usually about 0.1 to 3 μm and is appropriately selected depending on the material to be adhered and the like. If it is too thin, the adhesiveness will decrease, and if it is too thick, it does not make sense as an adhesive layer.

Next, the conductive layer 6 may be a semiconductor region as long as it has a conductivity (for example, an area resistance of 10 ¹² Ω / sq or less) that can be applied as a horizontal conduction path to the reversible display layer and a vertical electric field can be applied. In terms of voltage application loss and the like, good conductivity is better. For example, metal thin film or metal foil obtained by vapor deposition of metal such as aluminum, transparent conductive film such as ITO film, carbon black or aminium powder, etc. This is a conductive resin layer in which conductive powder is dispersed in a resin.

The protective layer 5 is positioned above the reversible display layer after transfer to protect the reversible display layer from pressure, external force, external environment and the like, and has heat resistance to display rewriting means such as a thermal head and roller electrodes. Improves abrasion resistance, scratch resistance, etc. The protective layer is made of a thermosetting resin, an ultraviolet curable resin, an electron beam curable resin or the like, and has a thickness of 0.5 to 10 μm.
Apply coating to a degree. For example, if a UV or electron beam curable resin such as soft urethane acrylate is used, excellent heat resistance, abrasion resistance, scratch resistance, suitable head touch to a thermal head, and cushioning property can be obtained.

Further, in the layer structure of FIG. 2, the primer layer 7
Is for improving the adhesion between the protective layer and the reversible display layer, or (not shown in FIG. 2), the barrier layer and the conductive layer, the conductive layer and the adhesive layer described below, and the like. The primer layer may be formed by a known adhesion treatment such as a primer treatment, and the material is not particularly limited,
For example, synthetic resins such as polyester resins, urethane resins, acrylic resins, silane coupling agents, titanate coupling agents, etc. are used.

The barrier layer 8 is a coating liquid solvent component (particularly organic solvent) when the conductive layer 6 is formed by coating as a conductive resin layer or when the adhesive layer is directly formed by coating without forming the conductive layer. It is a layer that prevents the solvent) from penetrating into the reversible display layer and deteriorating the liquid crystal alignment performance. Further, when the conductive layer is formed by metal vapor deposition, there is no problem of coating solvent, but the barrier layer is meant as a base layer for protecting the reversible display layer from heat during vapor deposition and for forming a smooth metal thin film surface. There is a peach. The base layer may be a thermosetting resin or a thermoplastic resin having heat resistance, but a water-soluble resin is preferable in view of the adverse effect of the coating solvent upon forming the base layer on the reversible display layer. Examples of the water-soluble resin include polyvinyl alcohol, polyvinylpyrrolidone, carboxymethyl cellulose and the like. Then, the barrier layer is formed by coating from these water-soluble coating liquids. 0.5 to 10 μm thickness to exhibit barrier properties
It should be enough.

The above-mentioned layers may be formed by a known coating means such as gravure coating, or a known printing means such as silk screen printing in the case of partially forming inside the transfer foil.

When the transparent state of the PDLC film which is the reversible display layer is used as a display (recording or erasing) state, when the transfer foil is transferred to an adherend, a layer which is a lower layer of the reversible display layer, For example, the conductive layer, the barrier layer, the adhesive layer, or the adherend may have a coloring effect, a light reflection effect, a light scattering effect, a light diffraction effect, or the like. Alternatively, a layer having these effects alone may be provided. Light scattering on PDLC film /
When using transmission, a light reflection effect (for example, a specular reflection layer) of a metal film or the like is preferable, and when using a difference in light absorption spectrum and light absorption amount due to addition of a dichroic dye, a coloring effect (for example, an arbitrary A layer colored in color) or a white light scattering effect (for example, a layer containing a white pigment) is preferable.

Then, the reversible display transfer foil as described above is transferred to an adherend in an appropriate shape to obtain a reversible display recording medium of the present invention having excellent display security and reliability. To be

The transfer of the transfer foil of the present invention to the adherend may be carried out by a conventionally known transfer method of a thermal pressure such as a circular pressure type or a flat pressure type. The heat and pressure conditions may be appropriately determined in consideration of the adhesiveness, the thermal deformation of the adherend, the resistance of the transfer foil including the reversible display layer, and the like. Further, for example, the cross section of the transfer foil may be half-cut from the side of the support on which the PDLC film is formed in order to improve the breakage of the foil after transfer. By doing so, even a tough film or a thick film foil can be satisfactorily transferred.

On the other hand, the adherend is not particularly limited, and if it is transferred to a simple plastic sheet, it becomes a recording medium having a display unit capable of reversible display. Of course, fixed information may be printed and formed by a known printing means before or after the fact. Further, if the transfer foil of the present invention is transferred to an information recording medium of invisible information, for example, a magnetic card, an IC card, an optical card, a non-contact IC card, etc., a display function can be easily added. The recording medium can be reversibly displayed according to the invention. If the adherend has a card-like shape, various synthetic resins such as vinyl chloride resin, polyester resin such as poly (ethylene terephthalate), polyolefin resin such as polypropylene, and paper are used as the material, A size of about 0.1 to 1 mm is usually used. However, the shape of the adherend is not limited to a card shape, and may be a molded product, and may be paper, a metal sheet, or the like, and the shape and material such as size and thickness are arbitrary and are not limited. In addition, in order to improve the adhesiveness of the display portion, a well-known primer treatment or other easy adhesion treatment may be performed on the adherend surface of the adherend.

One of the features of the present invention is that the display portion formed by transfer can be partially formed, and it may be formed not only on a part of the adherend but also on the entire surface. In the case of the above-mentioned magnetic card, IC card, or the like, the place to be formed is, for example, on the magnetic stripe if it does not affect the recording / reproducing of the information recording unit such as the magnetic stripe, IC module, or optical recording film. Etc. may be provided on the information recording section. The position of the display section is limited in the relationship with the terminal section especially in the case of an IC card in consideration of the adverse effect of the electric field used for the rewriting means, but data communication is performed by wireless contact with an external device. The contactless information recording medium does not have such a restriction.

If the transfer surface of the adherend on which the transfer foil is transferred is made of a flexible material, the pressure during transfer concentrates stress on the reversible display layer and disperses in the reversible display layer. It is possible to avoid destroying the liquid crystal shape. As such a material, there is a low temperature thermoplastic resin which exhibits a certain degree of flexibility when heated at the time of transfer, or a flexible foaming material such as a cushion. Specifically, it is a material obtained by foaming an ethylene-vinyl acetate copolymer with an azo compound-based foaming agent.

The reversible display recording medium of the present invention is also characterized in that the display portion is transferred and formed, so that the display portion is less likely to protrude than the surroundings. Although it can be partially formed even when it is formed by a label, the label becomes thicker by the thickness of the support. Incidentally, the thickness of the transfer foil of the present invention is, for example, 10
It is about 20 μm, and a recording medium having almost no protrusion can be obtained by thermal transfer to a thermoplastic resin substrate.

Next, the method of rewriting the display of the reversibly displayable recording medium of the present invention will be outlined by taking as an example the usage of erasing by applying an electric field and recording by heating.

First, the electric field application method is, for example, Japanese Patent Application No. 6-103249 and Japanese Patent Application No. 6-302 by the present applicant.
No. 701, "Non-contact liquid crystal alignment method and liquid crystal alignment device for liquid crystal display medium" (charging method) and Japanese Patent Application No. 6-302702.
"Liquid Crystal Alignment Method and Liquid Crystal Alignment Device for Liquid Crystal Display Medium"
(Electrode method), or various methods disclosed in Japanese Patent Application No. 6-333820 "Rewriting device for reversible display medium" (charging method + electrode method) may be used. The disclosed electric field application methods can be classified from various viewpoints, such as a non-contact method and a contact method, a charging method and an electrode method, a pair-row method in which a potential difference is applied from one side, and a facing method from both front and back sides, and a combination of these. However, it may be appropriately selected and used depending on the shape, physical properties, etc. of the recording medium, but from the point that there is no restriction on the adherend, the parallel array method in which a potential difference is applied from the surface side of the display unit is suitable. FIG. 3 shows an electric field applying (erasing) device 700 in which a charging method (non-contact method) and an electrode method (contact method) are combined, as an example of the pair-row method. In the figure, an electric field applying device 70
In No. 0, a charger 711 such as a corona charger is arranged between two ground rollers 712 made of conductive rubber or the like, and a guide roller 713 is arranged opposite to the ground roller 712. Then, the recording medium 10 having the transferred and formed display portion 11 moves between the earth roller 712 and the guide roller 713, and a vertical electric field is applied to the display portion located below the earth roller and the charger. There are various modes of the number of chargers or electrodes installed in each system.

In the three electric field application system of electrode-charger-electrode in FIG. 3, the central charger is applied (potential is applied without being grounded).
If an electrode is used, an electrode method, a contact method, and a counter-row method will be used. Further, if the electrodes on both sides are chargers, a charging method, a non-contact method, and a counter-row method can be used. Also, there are methods such as electrodes and chargers, electrodes and electrodes, chargers and chargers, and the like. However, in both cases, the adjacent electrodes or chargers are applied with different potentials (for example, ground potential and positive or negative potential, positive and negative potential, etc.).

In the electric field applying device 700 of FIG. 4, the structure of the portion of the recording medium 10 on the display portion 11 side is the same as that of the device of FIG. 3, but the portion on the back surface side is fixed and grounded. Instead, it is provided with a conductive plate 714 that floats in potential. In the figure, the recording medium 10 slides on the conductive plate 714 by the rotational drive of the earth roller 712 and passes under the corona charger 711. The electric field is applied by the potential difference between the corona charging surface having the conductive plate 714 as a transverse path and the ground roller. If the conductive plate 714 is grounded in the apparatus of FIG. 4, an electric field is applied by the vertical electric field between the corona charging surface and the conductive plate 714. In this case, it is the application of the opposed method, and it can be applied when the adherend is paper or the like and the conductivity of the adherend itself, specifically, the electric resistance including the thickness is relatively small with respect to the reversible display layer. .

On the other hand, as the heat applying means, in addition to a hot plate,
It is carried out by a thermal head used for a thermal transfer printer or the like suitable for pattern printing of characters or the like, or laser heating.

[0042]

In the transfer foil capable of reversible display of the present invention, by using the reversible display layer composed of the PDLC film as the display means capable of reversible display, it is difficult to rewrite for the purpose of falsification and display which is not erased in the natural environment can be performed. In addition, the transfer foil can form a thin display portion with a small rise. And
If the area resistance of the adherend surface of the adherend is 10 ¹² Ω / sq or less, a conductive layer is not required on the transfer foil for producing the recording medium of the present invention, and display is performed by applying an electric field from the display unit side. You can change the state. If the sheet resistance is 10 ¹² Ω / sq or more, a transfer foil provided with a conductive layer may be used. If a metal thin film layer or a metal foil is used as the conductive layer, it functions as a reflective layer, and if a carbon black-containing resin layer is used as the conductive resin layer, it also functions as a black colored layer.

Further, the protective layer protects the reversible display layer after transfer from external force, and obtains heat resistance, abrasion resistance, scratch resistance of the display portion, suitable head touch to the thermal head, and cushioning property. To be In addition, when a water-soluble polymer is used as the polymer matrix of the liquid crystal / polymer composite film of the reversible display layer, the barrier layer between the reversible display layer and the conductive layer causes
This prevents deterioration of the alignment performance of liquid crystal in the reversible display layer due to the coating solvent of the layer formed on the reversible display layer during the production of the transfer foil. Especially when the barrier layer is a water-soluble polymer, the prevention performance is good. Further, for the same reason, if the adhesive layer is also formed of an aqueous emulsion adhesive, deterioration of the alignment performance of the liquid crystal can be prevented.

The present invention will be further described with reference to Examples and Comparative Examples. Parts or ratios are based on weight unless otherwise specified.

[0045]

【Example】

Example 1 (Transfer Foil) : A transparent polyethylene terephthalate film having a thickness of 50 μm and having a peeling property on one side by a melamine treatment was used as a support, and the protective layer (thickness: 2 μm), primer layer (thickness 0.5 μm), reversible display layer [liquid crystal / polymer composite film] (thickness 7 μm), barrier layer (thickness 2 μm), conductive layer (aluminum vapor deposition layer: thickness 400Å) , And an adhesive layer (thickness 1 μm) were formed to obtain a reversible display transfer foil of the present invention.

* Protective layer (coating liquid for formation): UV-curable resin paint 100 parts (DPHA / urethane acrylate = 1/1) [DPHA: dipentaerythritol hexaacrylate] Solvent: isopropyl alcohol 100 parts * Primer layer ( Coating liquid for forming): Polyester urethane (UR-3200 manufactured by Toyobo Co., Ltd.) 100 parts Xylene diisocyanate 3 parts Toluene 100 parts Methyl ethyl ketone 100 parts

* Reversible display layer (coating liquid for formation): 3 parts of smectic liquid crystal (S-6, manufactured by Merck Japan Co., Ltd.) and dichroic dye (S-, manufactured by Mitsui Toatsu Chemicals, Inc.) 428,
(Black color development / transparent dichroism) 0.06 part is added to 70 ° C.
15.5 parts of a 10 wt% aqueous solution of polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., EG-05) was added to the solution mixed by stirring at 70 ° C., and mechanical dispersion was performed at 70 ° C. Furthermore, a 10 wt% aqueous solution of polyvinyl alcohol (KH-20, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) was added to this dispersion as a thickener, and smectic liquid crystal S-6 / (polyvinyl alcohol EG-05 + KH-20) = Add and stir until the ratio becomes 50/50 (weight ratio), and the average particle size of liquid crystal dispersion is 5
The coating liquid was μm.

* Barrier layer (coating liquid for formation): 10% aqueous solution of polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.,
KH-20)

* Adhesive layer (forming liquid for formation): Water-based polyester ester emulsion (manufactured by Toyobo Co., Ltd., MD-1200)

The coating formation of each layer except the metal layer was performed by the bar coating method as follows. First, after coating a protective layer of an ultraviolet curable resin on a support, irradiating it with ultraviolet rays to cure it, coating a primer layer, drying and then heating at 50 ° C. for one day to crosslink the primer layer. It was Then, the reversible display layer was applied, dried at 60 ° C. for 30 seconds, and then dried at room temperature for 24 hours. Next, a barrier layer is applied and dried at 60 ° C. for 30 seconds, then left at room temperature for 24 hours to remove residual moisture, and then aluminum is vacuum-deposited, and then an adhesive layer is applied and dried at 100 ° C. for 30 seconds. Let

Example 2 (recording medium) : Card made of vinyl chloride resin with a magnetic stripe (thickness 0.76 mm)
Then, the transfer foil prepared in Example 1 was heated and pressed for 1 second on a hot plate at 150 ° C., the support of the transfer foil was peeled off, and rewriting display of a size of 20 mm in length and 50 mm in width was made on the card. A part was formed to obtain a reversible display recording medium of the present invention. In addition, the protrusion height of the display unit is 3 to 5 μm.

Comparative Example 1 (Transfer Foil) : The following polymer / fatty acid composite film having a thickness of 7 μm was used as a reversible display layer, and the barrier layer was a vinyl chloride-vinyl acetate copolymer (manufactured by UCC, USA).
A transfer foil of a comparative example was obtained in the same manner as in Example 1 except that (VAGH) was used.

* Polymer / fatty acid composite film: A ratio of 20 parts by weight of stearic acid and 20 parts by weight of dodecanedioic acid to 100 parts by weight of vinyl chloride-vinyl acetate copolymer as a polymer matrix, and as a solvent Apply a coating solution using tetrahydrofuran on the primer layer, and
It was dried at 0 ° C. for 1 minute to form a reversible display layer.

Comparative Example 2 (Recording Medium) : A recording medium of Comparative Example 2 is obtained in the same manner as in Example 2 except that the transfer foil of Comparative Example 2 is used instead of the transfer foil of Example 1. It was

* Printing conditions: Printing was performed on the polymer / fatty acid composite film by printing at 0.6 mJ / dot, and erasing was performed by pressing at 80 ° C. hot plate for 2 seconds.

Comparative Example 3 (Recording medium by label) : A recording medium capable of reversible display was obtained by sticking labels together without using a transfer foil as a display portion. That is, a conductive layer, a reversible display layer, and a protective layer were sequentially laminated on one surface of 0.5 mm-thick polyethylene terephthalate as a base material, and the following adhesive layer (thickness 20 μm) was peeled on the other surface of the base material. Paper (thickness 10
0 μm) to form a reversible display label. The other materials and their thicknesses are the same as in Example 1.

* Adhesive layer: Acrylic ester pressure-sensitive adhesive (Nissetsu PE-1 manufactured by Nippon Carbide Industry Co., Ltd.)
18) * Release paper: Glassine paper (manufactured by Fujimori Industry Co., Ltd.)

Performance evaluation of recording medium:

* Writing: For those having a reversible display layer of a PDLC film, a white turbid state in which liquid crystals were randomly aligned (actually, the dichroic dye used turned black) was used as a writing state. Writing is resolution 6do
With the end thermal head of t / mm, pulse cycle is 3.0m
The heating was performed at 0.4 mJ / dot at a duty ratio of 50% for sec.

* Erasing: An erasing device using a corona charger (output: 5 kV) and an earth roller was used to convey the recording medium 10 at a conveying speed of 500 mm / sec for erasing. FIG.
Is also a schematic configuration diagram of the erasing device 700. The corona charger has a tungsten wire length of 80 mm, the earth roller is a roller made of stainless steel having a diameter of 10 mm and a width of 50 mm, and the medium is conveyed to the corona charger. It is installed 5 mm away from the corona charger on the upstream and downstream sides of the path. The corona charger and the earth roller are installed on the display surface side of the recording medium.

* Evaluation results: -Example 2: Both printing and erasing were good. And
The display was excellent in tampering prevention.・ Comparative Example 2: The display disappears when it is brought into contact with a hot plate of 80 ° C,
Next, the displayed contents were easily rewritten by printing with a thermal head. -Comparative example 3: The amount of protrusion of the display portion by the label (about 0.5 m
m) was too large, and the display part was peeled off when the recording medium was transported and carried.

[0063]

According to the transfer foil capable of reversible display of the present invention, since it has a reversible display layer capable of rewriting visible information, reversible display is possible by simply transferring the transfer foil to an adherend. A recording medium can be easily obtained. Moreover, since the PDLC film that requires external energy of both heat and electric field is used as the reversible display layer, it is possible to obtain a display unit having high display security, excellent reliability, and excellent visibility. Further, the position of transferring the transfer foil to the adherend can be easily formed not only on the entire surface of the adherend but also on a part of the adherend.
Since the layer to be transferred is thin and flat, it does not protrude like a display portion by a label and is not peeled off from the step around the display portion, and is excellent in durability during carrying and mechanical durability during rewriting.

The protective layer protects the reversible display layer after transfer from external force, and the heat resistance, abrasion resistance, scratch resistance, suitable head touchability for the thermal head, cushioning property, etc. of the display part are improved. A recording medium having an excellent display section can be obtained. Further, when a water-soluble polymer is used as the polymer matrix of the liquid crystal / polymer composite film of the reversible display layer, the barrier layer between the reversible display layer and the conductive layer prevents the reversible display layer from forming a reversible display layer. It is possible to prevent the alignment performance of the liquid crystal in the reversible display layer from being deteriorated by the coating solvent for the layer formed by coating on the layer, and to maintain excellent display performance. Especially when the barrier layer is a water-soluble polymer, the prevention performance is excellent. Further, for the same reason, deterioration of the alignment performance of the liquid crystal can be prevented by using an aqueous emulsion or a water-soluble polymer adhesive for the adhesive layer.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view of an embodiment of a reversible display transfer foil of the present invention.

FIG. 2 is a longitudinal sectional view of another embodiment of the transfer foil capable of reversible display according to the present invention.

FIG. 3 is a schematic configuration diagram showing an example of a display erasing (electric field applying) device that can be used for the recording medium of the present invention.

FIG. 4 is a schematic configuration diagram showing another example of a display erasing (electric field applying) device that can be used for the recording medium of the present invention.

[Explanation of symbols]

 1 reversible display transfer foil 2 peelable support 3 reversible display layer (= PDLC film) 4 adhesive layer 5 protective layer 6 conductive layer 7 primer layer 8 barrier layer 10 reversible display recording medium 11 display unit 700 electric field applying device (Erasing device) 711 Charging device 712 Earth roller (electrode) 713 Guide roller 714 Conductive plate

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C09J 7/02 JLH G02F 1/13 505 G02F 1/13 505 1/1333 1/1333 G09F 3/00 Q G09F 3/00 7416-2H B41M 5/26 102

Claims (9)

[Claims] 1. At least a liquid crystal / liquid crystal on a peelable support.
A reversible display transfer foil comprising a reversible display layer, which is composed of a polymer composite film and whose light transmittance or absorbance is reversibly changed by heat and an electric field, and an adhesive layer, which are sequentially laminated. 2. The reversible display transfer foil according to claim 1, further comprising a protective layer between the peelable support and the reversible display layer. 3. The reversible display transfer foil according to claim 1, further comprising a conductive layer between the reversible display layer and the adhesive layer. 4. The reversible display transfer foil according to claim 3, wherein the conductive layer is made of any one of a metal thin film, a metal foil, and a conductive resin layer. 5. The liquid crystal / polymer composite film constituting the reversible display layer comprises a water-soluble polymer as a polymer, and has a barrier layer between the reversible display layer and the conductive layer. The transfer foil capable of reversible display according to item 4. 6. The reversible display transfer foil according to claim 5, wherein the barrier layer is made of a water-soluble polymer. 7. The reversible display transfer foil according to claim 5, wherein the adhesive layer is formed of an adhesive of an aqueous emulsion or a water-soluble polymer. 8. A reversibly displayable recording medium, wherein the reversibly displayable transfer foil according to claim 1 or 2 is transferred and formed on an adherend having an area resistance of 10 ¹² Ω / sq or less. . 9. A transfer foil capable of reversible display according to any one of claims 3 to 7 is transferred and formed on an adherend having an area resistance of 10 ¹² Ω / sq or more. Reversible display recording medium.