JP2002254811A - Reversible displaying medium having ink acceptability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reversible displaying medium having an ink acceptability, which has an excellent water-base ink acceptability under the state that information is written with a water-base ink on the reversible displaying medium provided with a protective layer thereon and, at the same time, which also has a resistance to the heating at printing and erasing. SOLUTION: Protein particles are added to the protective layer 1 of the reversible displaying medium, which is formed by providing at least a reversible image forming layer 3 and the protective layer 1 on a transparent supporting base material 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reversible display medium, and more particularly to a reversible display medium having ink receptivity which has both reversible recording and high designability and design freedom, as well as cards and seals. The present invention relates to a reversible display medium having ink receptivity and used integrally with paper or the like.

[0002]

2. Description of the Related Art Reversible display media are mainly used in card fields such as prepaid cards and point cards. These reversible recordings are described in JP-A-2-188293.
Compounds described in Japanese Patent Application Laid-Open Publication No.
There is one using an organic low molecular weight / high polymer represented by JP-A-63094.

Generally, when a leuco compound is used,
A change from a transparent or white background color to mainly blue or black is used for display, and when an organic low molecular weight / high molecular weight is used, a change from transparent to white is used for display. An external thermal stimulus is used to write an image on these reversible display media, and a thermal head is used because of the necessity of precise printing and downsizing of the reading / writing device. In particular, the reversible display medium using a leuco compound is transparent before printing, and when used as an integral part of a card or paper, can be processed on a picture, providing high designability and design. It is expected that usage will increase in the future due to the freedom of use.

Heretofore, printing has been performed on a reversible display medium using a leuco compound. However, for example, when writing different information for each card such as personal information and photographs / pictures, the printability of the water-based ink by the ink jet method is necessary, but in general, a reversible display medium composed of an ultraviolet curable resin or the like is used. The printability of the protective layer for aqueous ink is low. In addition, a method of adding a hydrophilic resin having a receptivity to water-based ink to the protective layer is also conceivable, but it has been difficult to impart heat resistance during printing and erasing.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an aqueous ink is used for a reversible display medium provided with a protective layer, for example, by an ink jet method. When writing information,
It is an object of the present invention to provide a reversible display medium having excellent ink receptivity, excellent in receptivity to water-based ink, and resistant to heating during printing and erasing.

[0006]

The present invention relates to a reversible display medium comprising at least a reversible image forming layer and a protective layer provided on a transparent supporting substrate, wherein protein particles are added to the protective layer. And a reversible display medium having ink receptivity characterized by having printability for aqueous ink.

The present invention also relates to a reversible display medium having ink receptivity according to the present invention, wherein the reversible image forming layer comprises at least a leuco compound, and a color-reducing agent which develops or reduces color by reacting with the leuco compound. A reversible display medium having ink receptivity, characterized by comprising a binder.

Further, the present invention provides the reversible display medium having ink receptivity according to the above invention, wherein the surface of the protective layer has a center line average roughness (Ra) of 0.5 μm to 50 μm. It is a reversible display medium with ink acceptability.

Further, the present invention is characterized in that the reversible display medium having ink receptivity according to the above invention is integrated on a part or the whole surface of a substrate such as a card or paper via an adhesive layer. It is a reversible display medium with ink acceptability.

[0010]

Embodiments of the present invention will be described below. FIG. 1 is a sectional view showing an embodiment of a reversible display medium having ink receptivity according to the present invention. As shown in FIG. 1, a reversible display medium having ink receptivity comprises a reversible image forming layer (3), an intermediate layer (2), and a protective layer (1) on a transparent support substrate (4). Is formed.

FIG. 2 is a sectional view showing an embodiment of a reversible display medium having ink receptivity according to the fourth aspect. As shown in FIG. 2, the reversible display medium having ink receptivity is a card substrate (6) having a front side printing layer (7a) and a back side printing layer (7b) formed on the front and back surfaces, respectively. A reversible display medium having ink receptivity as shown in FIG. 1 is provided on the entire surface of the front surface via an adhesive layer (5), and the back surface thereof is a card substrate (6).
It is integrated toward the surface of. The reversible image forming layer (3), the intermediate layer (2), the protective layer (1), and the adhesive layer (5) are formed by a printing method, a coating method, and the like. The integration is performed by a hot press.

The protective layer (1) in the present invention plays a role of protecting the reversible image forming layer, and includes a printing method,
It can be provided with a thickness of 0.2 μm to 20 μm by a coating method or the like. Examples of the resin used include known resins such as acrylic resin, urethane resin, vinyl chloride resin-vinyl acetate copolymer resin, polyester resin, melamine resin, epoxy resin, polystyrene resin, and polyimide resin. Thermoplastic resin, ultraviolet ray or electron beam curable resin alone or as a mixture. In particular,
For curing by ultraviolet irradiation, it is preferable to use a photopolymerization initiator. The photopolymerization initiator is not particularly limited, and benzoic acid esters, benzophenone derivatives, benzoin derivatives, thioxanthone derivatives, and the like can be used. The content of these polymerization initiators is preferably about 1% by weight to 5% by weight based on 100% by weight of the ultraviolet or electron beam curable compound.

Further, in order to improve the resistance and prevent sticking, a curing agent for crosslinking the resin, waxes such as polyethylene wax, carnauba wax and silicone wax, or calcium carbonate, zinc stearate, silica, alumina, talc and the like are used. Fats and oils such as extender pigments and silicone fats and oils can be added within a range that does not impair transparency. In order not to sacrifice the resistance to heating while improving the receptivity of the aqueous ink, the particle diameter is 2 μm to
μm protein particles are added at a ratio of 10% to 30% by weight with respect to 100% by weight of the binder.

The intermediate layer (2) is for preventing the compound contained in the reversible image forming layer such as a leuco compound from seeping out, and for compensating the adhesion between the protective layer and the reversible image forming layer. It can be provided if necessary. For the intermediate layer, a polymer compound such as polyurethane, polyester, polyethylene vinyl alcohol, polyvinyl chloride, polyvinyl chloride-vinyl acetate copolymer, or cellulose, or a mixture thereof can be used. If necessary, a curing agent can be added.

The reversible image forming layer (3) is, for example, a thermochromic composition utilizing a reversible color-forming reaction between a leuco compound dispersed in a binder and a developer, and is formed by a printing method, a coating method or the like. It can be provided with a film thickness of about 4 μm to 20 μm. Usually used as a colorless or light-colored leuco compound used in the heat-sensitive recording layer, typically represented by pressure-sensitive recording paper, heat-sensitive recording paper, photosensitive pressure-sensitive paper, current-sensitive heat-sensitive recording paper, those used for heat-sensitive transfer paper, Xanthenes, spiropyrans, lactones, fluorans, sultones, and the like having a partial skeleton such as lactone, sultone, and spiropyran are used, but are not particularly limited.

Specific examples include 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide,
3,3-bis (p-dimethylaminophenyl) phthalide, 3,3-bis (1,2-dimethylindole-3-
Yl) -6-dimethylaminophthalide, 3-dimethylamino-6-chloro-7-methylfluoran, 3,3-bis (9-ethylcarbazol-3-yl-5-dimethylaminophthalide, 3-dimethyl Amino-7-dibenzylaminofluoran, 3-diethylamino-7-chlorofluoran, 3-diethylamino-6-methyl-7-anilinofluoran, 3-piperidino-6-methyl-7-anilinofluoran, 3- (n-ethyl-n-tolyl) amino-6-methyl-7-anilinofluoran, 3-dibutylamino-6-methyl-7-anilinofluoran, 3-
(N-ethyl-n-isoamyl) amino-6-methyl-
Examples thereof include 7-anilinofluoran and 3- (n-ethyl-n-tetrahydrofuryl) amino-6-methyl-7-anilinofluoran, which are used alone or in combination.

On the other hand, the color-developing agent is a compound having both a color-developing effect and a color-reducing effect on a leuco compound by reversibly releasing protons under the action of thermal energy. That is,
It has both an acidic group consisting of a phenolic hydroxyl group or a carboxyl group and a basic group consisting of an amino group, and becomes acidic or basic due to a difference in heat energy to cause the leuco compound to develop or decolor. The basic group may be present as a functional group or may be present as a part of a compound. In addition, by using a color-developing agent having either a functional group of an acidic group or a basic group of the color-developing agent, only a color-forming effect can be exhibited.

Examples of the color-reducing agent having an acidic group and a basic group as functional groups include, for example, aminobenzoic acids, hydroxyaminobenzoic acids, aminophenols, aminonaphthoic acids, nicotinic acids and the like. Specific examples include m-aminobenzoic acid, o-aminobenzoic acid, 4-amino-3-methylbenzoic acid, 3-amino-4-methylbenzoic acid, 2-amino-5-ethylbenzoic acid, 3-amino -4-butylbenzoic acid, 4-amino-3-methoxybenzoic acid, 3-amino-4-ethoxybenzoic acid, 2-amino-5-chlorobenzoic acid, 4-amino-3-bromobenzoic acid, 2-amino -2-nitrobenzoic acid, 4-amino-3
-Nitrobenzoic acid, 3-amino-4-nitrile benzoic acid, aminosalicylic acid, diaminobenzoic acid, 2-methyl-5-aminonaphthoic acid, 3-ethyl-4-aminnaphthoic acid, nicotinic acid, isonicotinic acid, 2- Examples include methylnicotinic acid and 6-chloronicotinic acid.

The compound having a basic group as a part of the salt compound includes a salt or a complex salt of a compound having a phenolic hydroxyl group or a carboxyl group and a compound having an amino group, such as hydroxybenzoic acids and hydroxysalicylic acid. Or a complex salt of an acid such as carboxylic acids, gallic acids and bisphenolacetic acid with a base such as aliphatic amines, phenylalkylamines and triallylalkylamines.

Specific examples thereof include p-hydroxybenzoic acid-alkylamine salt, p-hydroxybenzoic acid-phenylalkylamine salt, m-hydroxybenzoic acid-alkylamine salt, 2,4-dihydroxy-alkylamine salt, 4,5-dihydroxybenzoic acid-trialkylamine salt, 4,5-dihydroxybenzoic acid-tolylalkylamine salt, p-hydroxybenzoic acid methyl-alkylamine salt, p-hydroxybenzoic acid stearyl-alkylamine salt, gallic acid -Alkylamine salts, stearyl gallate-alkylamine salts, bisphenolacetic acid-alkylamines, bisphenolacetic acid octyl-alkylamine salts, and the like, used alone or in combination. It should be noted that the leuco compound and the color-reducing agent are not limited to these, and one or more of these may be used as a mixture.

The binder used includes acrylic resin, polyester resin, polyurethane resin, polyurea, melamine, polycarbonate, polyamide, polyvinylpyrrolidone, polyvinyl alcohol,
Resins such as polyvinyl chloride and polyvinyl butyral may be used alone, mixed or copolymerized. Furthermore, in order to improve the repetitive print erasure resistance of the reversible thermosensitive recording section, a curing agent for crosslinking three-dimensionally corresponding to the binder, a crosslinking agent, and the like can be added to the binder in an amount of 0.5% to 10% by weight based on the binder. . Further, an ultraviolet absorber having relatively high compatibility with the leuco compound can be added to improve the resistance.

The transparent support substrate (4) is made of polyethylene, polypropylene, or other transparent polymer material having a relatively small thickness that is mechanically tough, flexible and flexible, and has a thickness of 10 μm. A plastic film of about 100 μm or the like is used. Preferably, a polyethylene terephthalate (PET) film having a thickness of 25 μm to 50 μm is used in consideration of transportability and workability during coating and printing.

The adhesive layer (7) may be a material usually used as an adhesive, such as a vinyl chloride-vinyl acetate copolymer, a polyester resin, and an acrylic resin, and is not particularly limited. The thickness is set to about 0.1 μm to about 20 μm by an existing method such as a gravure method.

The card base material (6) is used as an object to be integrated with the reversible display medium having ink receptivity shown in FIG. 1, and is made of white, colored or transparent polyvinyl chloride resin, Materials such as polyester resins, polyolefin resins such as polyethylene and polypropylene, polycarbonate resins, and acrylonitrile-butadiene-styrene copolymer resins can be used. The thickness is selected from the range of 50 μm to 2 mm in consideration of printability. These preferably, the substrate may be further divided into a center core and an oversheet and finally laminated,
In this case, a non-contact IC chip and an antenna may be arranged on a base material in advance, and a center core may be formed by laminating several layers of sheets.

The printing layer is used alone or as a mixture of ordinary coloring inks, fluorescent inks, infrared coloring inks, ultraviolet coloring inks, etc., and is printed by a conventionally known gravure printing method, screen printing method, offset printing method or the like. It can be provided using a method or a pattern transfer sheet prepared in advance.

[0026]

The present invention will be described in detail with reference to the following examples. (Preparation of Coating Solution) Coating Solution for Reversible Image Forming Layer 2- (2-chlorophenylamino) -6-diethylaminofluoran, (leuco compound) 20 parts by weight Bisphenolacetic acid-laurylamine salt, ( 40 parts by weight, methacrylic resin, (binder resin), 30 parts by weight, amide N-stearylstearate, (sensitizer), 40 parts by weight, toluene … 500 parts by weight ○ Coating liquid for protective layer (dispersed and used) ・ Photoreactive monomer (Aronix M-400 manufactured by Toa Gosei Chemical Co., Ltd.)… 50 parts by weight ・ Photopolymerization initiator (Darocur 1173 manufactured by Merck) ……… … 3 parts by weight ・ Protein powder ink, (average particle size 5 μm) ...... 10 parts by weight (Protein coat WR-452 manufactured by Idemitsu Techno Fine Co., Ltd.) ・ Charcoal Calcium 1.5 parts by weight (Shiraishi Kogyo Co., Ltd., white luster O, average particle diameter 0.03 μm) ・ Ethanol 150 parts by weight ○ Coating solution for adhesive layer ・ Vinyl chloride-vinyl acetate copolymer ............ 30 parts by weight Polyester resin 20 parts by weight (Stafix SOC-30M manufactured by Fuji Photo Film Co., Ltd.) Methyl ethyl ketone 50 parts by weight Toluene 50 parts by weight

<Example 1> A transparent supporting substrate having a thickness of 2
Using a 5 μm transparent PET sheet, a reversible image forming layer coating solution was applied with a bar coater at 7 μm, and a protective layer coating solution as a protective layer was applied with a bar coater.
UV at about cm2, irradiation amount about 700mJ / cm2
It was cured and provided at 6 μm. Adjust the shape to a card size.
4. A reversible display medium (sheet) is fixed to a card base material having a thickness of 76 mm with a double-sided adhesive tape, and a printing / erasing terminal (KU-R28611NKE manufactured by Kyushu Matsushita Electric Co., Ltd .; thermal head 807Ω; erasing heating ceramic bar) When printing was performed at an energy of 0.655 mJ / dot at 14 Ω), a clear coloration of the leuco compound was obtained (optical density: about 1.0). Further, when the erasing operation was performed at the erasing temperature (140 ° C.), the printed image could be erased without remaining unerased or re-colored. In addition, inkjet printer (PM-760C manufactured by Seiko Epson Corporation)
When printing was carried out using, printing was possible without problems such as blurring and blurring.

Example 2 A transparent support having a thickness of 2
Using a 5 μm transparent PET sheet, a reversible image forming layer coating solution was applied with a bar coater at 7 μm, and a protective layer coating solution as a protective layer was applied with a bar coater.
UV at about cm2, irradiation amount about 700mJ / cm2
It was cured and provided at 6 μm. An adhesive layer of about 5 μm was provided on the side opposite to the side on which the reversible image forming layer was provided, and the printed card base was integrated with a 115 ° C. roll laminating machine. Printing
Terminal for erasure (KU-R286 manufactured by Kyushu Matsushita Electric Co., Ltd.)
11NKE; thermal head 807 Ω; erasing and heating ceramic bar 5.14 Ω), printing was performed using an energy of 0.655 mJ / dot. As a result, a clear coloration of the leuco compound was obtained (optical density: about 1.0). ). Also,
When the erasing operation was performed at the erasing temperature (140 ° C.), the printed image could be erased without remaining unerased or reoccurring colors.
When printing was performed using an ink jet printer (PM-760C manufactured by Seiko Epson Corporation), printing was possible without problems such as blurring and blurring.

[0029]

According to the present invention, the protective layer is cured by ultraviolet light because the protein particles are added to at least the reversible image forming layer and the protective layer of the reversible display medium provided with the protective layer. Even if it is composed of a water-soluble resin, it is excellent in the receptivity of the aqueous ink when writing information using the aqueous ink by the ink jet method, and has the ink receptivity that has the resistance to heating during printing and erasing. It becomes a display medium. This makes it easy to print individual pictures such as personal information and photographs in the final step, and dramatically increases the degree of freedom in design.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a reversible display medium having ink receptivity according to the present invention.

FIG. 2 is a sectional view showing an embodiment of a reversible display medium having ink receptivity according to claim 4;

[Explanation of symbols]

 Reference Signs List 1 Protective layer 2 Intermediate layer 3 Reversible image forming layer 4 Transparent support substrate 5 Adhesive layer 6 Card substrate 7a Front print layer 7b Back print layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI FI theme coat ゛ (Reference) B41M 5/18 101A F-term (Reference) 2C005 HA10 HB04 HB14 JA09 JC02 KA40 2H026 BB02 BB21 CC00 DD42 DD55 EE08 FF11 2H086 BA15 BA31 BA41

Claims (4)

[Claims] 1. A reversible display medium comprising at least a reversible image-forming layer and a protective layer provided on a transparent support base material, wherein protein particles are added to the protective layer to improve printability with aqueous ink. A reversible display medium having ink receptivity, characterized by having it. 2. The ink receiving material according to claim 1, wherein said reversible image forming layer is composed of at least a leuco compound, a developer and a color reducing agent which reacts with said leuco compound to develop or reduce color. Reversible display medium 3. The center line average roughness (R) of the surface of the protective layer.
3. The reversible display medium having ink receptivity according to claim 1, wherein a) is 0.5 μm to 50 μm. 4. The reversible display medium having ink receptivity according to any one of claims 1 to 3, partially or entirely on a substrate such as a card or paper via an adhesive layer. A reversible display medium having ink receptivity characterized by being integrated.