JP2002127600A - Composite heat sensitive recording layer, heat sensitive recording medium, heat sensitive recording layer transfer sheet, label for adhering heat sensitive recording layer, and method for recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To independently record or erase a reversible heat sensitive recording layer and a heat sensitive recording layer when both the reversible recording layer and the heat sensitive recording layer are superposed and used. SOLUTION: The composite heat sensitive recording layer comprises a heat sensitive breakdown layer 2, a near infrared absorbable layer 5, a transparent heat insulation layer 3, and a reversible heat sensitive recording layer 5 sequentially laminated on a base 12. The composite layer may further comprise a colored layer 6 between the base 12 and an optical recording layer 2, and a protective layer 8 or the like laminated on an uppermost layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a layer capable of thermal destructive recording using heat generated by photothermal conversion of a near-infrared absorptive layer upon irradiation with near-infrared laser light, a thermal recording method using a thermal head and the like. While the erasable layer overlaps, when performing thermal recording or thermal erasure on each layer, a composite thermosensitive recording layer that can eliminate the effect on other layers, and such a composite thermosensitive recording layer The present invention relates to a thermosensitive recording medium provided.
In particular, the present invention relates to a thermal destructive recording using heat generated by photothermal conversion of a near-infrared absorbing layer upon irradiation of near-infrared laser light or the like from the side of the layer capable of thermal recording, that is, one side, and a thermal head. And the like. The present invention also relates to a heat-sensitive recording layer transfer sheet suitable for applying such a composite heat-sensitive recording layer to an adherend such as a card, and a label for applying the heat-sensitive recording layer. Furthermore, the present invention also relates to a recording method for performing recording on the above-described composite thermosensitive recording layer, thermosensitive recording medium, thermosensitive recording layer transfer sheet, and label for applying the thermosensitive recording layer.

[0002]

2. Description of the Related Art In cards and the like, individual information and the like are printed as a recording body and provided to a client whenever necessary. In this case, as a card which is a base of the ID card (one on which individual information is not recorded), the card itself is often a material capable of holding information. In order to enable immediate printing, printing is performed using a material whose hue or light reflectivity changes depending on the energy given during printing, or a material that accepts a coloring material given externally by printing. Possible areas are often formed.

[0003] For example, in the case of a plastic card, since the plastic material is embossable,
The credit card number, the name of the contractor, the expiration date, and the like can be recorded by forming uneven characters. Also, card base material,
Alternatively, a specially laminated dye-receptive resin layer can be used to print images such as characters or facial photographs using an ink ribbon containing a sublimable dye, or to form an ink-receptive layer and contract. Some people have to sign.

[0004] Alternatively, in a prepaid card for transportation, a thermosensitive coloring layer is formed on one side, and the contents of use, collection fee, balance, etc. are printed each time the card is used. Even in a regular ticket, the content is printed on the recording layer having the same thermosensitive coloring at the time of issuance.

[0005] In the above-mentioned cards and information recording media other than cards, it is rare to prepare a completely blank state and print all information every time it is issued. The reason is that the printing means used at the time of issuance has a limited performance. For example, recording using a laser beam enables fine recording, but the material is limited and only binary recording can be performed. According to the sublimation transfer method, a high-quality color image can be obtained. But it is not suitable for recording on the whole surface. Further, according to the thermal recording, although the processing speed is high, the recording is limited to the binary recording of a single color.

Therefore, in actual operation, the amount of information to be printed at the time of issuance is reduced as much as possible. For example, in the case of a credit card or bank deposit / saving card, the name of the issuing company or the name of the bank, the name of the card, the surface pattern, the item name such as "expiration date", a notice, etc. are printed by a normal printing method. In the event of issuance, information is recorded on the magnetic stripe, the card issue number in embossed characters, the contractor's name, and the expiration date are formed. Alternatively, in the case of a commuter pass, a copy-forgery-inhibited pattern with a railroad company mark etc. printed on the front side and a note etc. printed on the back side, and when issued, the purchaser's name, age, boarding section, via , Expiration date, etc. are printed.

However, if several kinds of information to be printed at the time of issuance are recorded in the same manner, it becomes easy for a person who plans forgery or falsification to prepare recording means and to record, so that forgery or falsification is easy. For the purpose of increasing the difficulty of alteration, it is desired to use a plurality of different recording means in combination and to record in the same area in an overlapping manner.

Although there are various recording means to be selected, thermal recording is mainly performed by a thermal head in that printing can be performed at high speed in accordance with information output when a card or the like is issued. Materials that can be used for thermal recording with a thermal head are a two-component thermosensitive coloring layer (irreversible coloring) such as leuco dye and acid developer, and capable of thermal recording and thermal erasing by dispersing fatty acids etc. in a resin matrix. There is a reversible thermosensitive recording layer and a thermosensitive destruction layer using a metal thin film having a relatively low melting point.

However, when these two types of layers are superimposed and recording is to be performed by a contact type thermal head, heat is always transmitted from the side where the head contacts, so that recording is performed independently on each layer. Is impossible. For example, even when recording is to be performed on the lower layer, recording (or recording or erasing when the upper layer is a reversible thermosensitive recording layer) is performed on an undesired upper layer due to the influence of heat.

[0010]

Accordingly, in the present invention, when two types of recording layers, both of which are subjected to thermal recording, are used in an overlapping manner, recording on each layer is performed independently. In particular, when the thermosensitive layer and the reversible thermosensitive recording layer capable of thermal recording and thermal erasing are used together, the recording (erasing in some cases) of each layer is independent. It is an object of the present invention to make it possible to perform the operation.

[0011]

SUMMARY OF THE INVENTION The above-mentioned object is to provide a layer in which thermal recording (or erasing) can be performed on top of each other, and thermal recording (or erasing) of a contact type by a thermal head is provided on the upper layer side. ), And on the lower side,
By covering the near-infrared absorbing layer and using the heat generated by irradiating low-power near-infrared laser light, it is possible to eliminate the problem by performing thermal recording by the optical contact method. found.

According to a first aspect of the present invention, at least a heat-sensitive destruction layer,
The present invention relates to a composite thermosensitive recording layer in which a near infrared absorbing layer, a transparent heat insulating layer, and a reversible thermosensitive recording layer are sequentially laminated. The second invention relates to the composite thermosensitive recording layer according to the first invention, wherein a coloring layer is laminated on the heat-sensitive destruction layer on the side opposite to the near-infrared absorbing layer. A third invention is the composite thermosensitive recording layer according to the first or second invention, wherein the reversible thermosensitive recording layer contains a dye precursor that does not absorb in the near infrared region after coloring. It is about. A fourth invention is the composite thermosensitive recording layer according to any one of the first to third inventions, characterized in that an adhesive layer is laminated on an exposed surface of the composite thermosensitive recording layer on the side of the thermosensitive destruction layer. It is about. A fifth invention is characterized in that at least a part of the substrate is laminated, with the heat-sensitive destruction layer side of the composite heat-sensitive recording layer according to any one of claims 1 to 4 facing the base material side. The present invention relates to a heat-sensitive recording medium. A sixth invention is a heat-sensitive recording layer, wherein the reversible heat-sensitive recording layer side of the composite heat-sensitive recording layer according to any one of claims 1 to 4 is laminated on a peelable surface of a peelable substrate sheet. It relates to a transfer sheet. The seventh invention is
5. A label for attaching a thermosensitive recording layer, wherein the reversible thermosensitive recording layer side of the composite thermosensitive recording layer according to claim 1 is laminated on a transparent base material sheet. An eighth invention provides the label for attaching a heat-sensitive recording layer, wherein each label has the requirements of the composite heat-sensitive recording layer according to any one of claims 1 to 4, and the transparent heat-insulating layer is a transparent substrate sheet. It is about. The ninth invention is claim 1
The near-infrared absorption of the composite thermosensitive recording layer according to any one of claims 4 to 7, the thermosensitive recording medium according to claim 5, the transfer sheet according to claim 6, or the label for applying the thermosensitive recording layer according to claim 7 or 8. The thermosensitive layer was irradiated with near-infrared laser light to generate heat by light-to-heat conversion, and the resulting heat was used to perform thermosensitive recording on the thermosensitive layer, and the reversible thermosensitive recording layer was heated. The present invention relates to a recording method including performing thermal recording and / or thermal erasure by contacting recording means.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a composite thermosensitive recording layer 1 which is a characteristic part of the present invention.
As shown in (a), from below, a heat-sensitive destruction layer 2 composed of a metal thin film or the like, a near-infrared absorbing layer 5, a transparent heat-insulating layer 3 composed of a transparent resin or the like, and a polymer matrix and a fatty acid The reversible thermosensitive recording layer 4 is sequentially laminated. The composite heat-sensitive recording layer 1 is preferably used by being laminated on an adherend such as a card base material so that the heat-sensitive destruction layer 2 side is in contact.

Various functions can be laminated on the above basic laminated structure to improve the function. less than,
The addition of those layers will be described with reference to FIGS.

As shown in FIG. 2, the composite thermosensitive recording layer 1 may have a colored layer 6 laminated on the lowermost layer. The addition of the coloring layer 6 increases the visibility of the record formed by the fine holes in the heat-sensitive destruction layer 2. In FIG. 2, the colored layer 6 is located at the lowermost layer of the composite thermosensitive recording layer 1 shown in FIG.
Are added to show a structure corresponding to a laminated structure.
As described later, the colored layer 6 may be a magnetic recording layer containing a magnetic material powder.

FIG. 3 shows a structure in which the protective layer 8 is added to the uppermost layer and the adhesive layer 7 is added to the lowermost layer, which has not appeared in the above description. The protective layer 8 and the adhesive layer 7 are laminated by adding only the protective layer 8 to the uppermost layer for each structure as shown in FIGS. In some cases, additional layers may be laminated, or the protective layer 8 may be laminated on the uppermost layer and the adhesive layer 7 may be laminated on the lowermost layer.

FIG. 4 shows a state in which the composite thermosensitive recording layer is laminated on a substrate 12 such as a card substrate as an adherend. In FIG. 4 (a), FIG. 4) are laminated. In FIG. 4B, the lowermost adhesive layer 7 of the composite thermosensitive recording layer 1 shown in FIG.
Are omitted on the base material 12. Both are merely examples of the composite thermosensitive recording layer 1 that can be laminated,
Any of the composite thermosensitive recording layers described so far can be laminated on the substrate 12.

In laminating the composite thermosensitive recording layer 1 and the substrate 2, the composite thermosensitive recording layer 1 may be laminated on the entire surface of the substrate 12 or on a part of the substrate 12. ,
It may be stacked at one place on the base material 12 or at a plurality of places. The composite thermosensitive recording layer 1 may be laminated on only one surface of the substrate 12, or may be laminated on both the front and back surfaces of the substrate 12.

When laminating the composite thermosensitive recording layer 1 on the substrate 12, as shown in FIGS. 4 (a) and 4 (b), the composite thermosensitive recording layer 1 is simply placed on the substrate 12 and fixed. When the base material 12 is composed of a laminate of a plurality of sheets, it can be laminated not only on the surface of such a laminate, but also between a plurality of sheets constituting the substrate. For example, an oversheet and a core sheet of a laminate of four sheets of a transparent oversheet, two opaque core sheets, and a transparent oversheet, as in a typical credit card or bank savings card. And may be laminated between them.

In the present invention, the composite thermosensitive recording layer 1 of the above-described various embodiments is laminated on the substrate 12 sequentially from the side in contact with the substrate 12 by coating or the like (partly by vapor deposition or the like). Although it is also possible to laminate, a laminated body to which the composite thermosensitive recording layer is applied is formed once on a flexible substrate sheet separate from the substrate 12, and the formed laminated body is laminated on the substrate 12. It is industrially more convenient to carry out such a process. Such a laminate may be formed of a transfer sheet and a label.
There are types.

FIGS. 5A and 5B show an example of such a transfer sheet 21 type.
(A) shows a reversible thermosensitive recording layer 4, a transparent heat-insulating layer 3, a near-infrared absorbing layer 5, a heat-sensitive destructive layer 2 on the releasable surface (lower surface in the figure) of the releasable substrate sheet 22. , The colored layer 6 and the adhesive layer 7 are sequentially laminated downward. 5B, the protective layer 8 is first laminated on the releasable surface of the releasable base material sheet 21, and the other components are the same as those shown in FIG. 5A. It is. Each transfer sheet is placed on the substrate 12 as an adherend with the adhesive layer 7 side as the adherend side, and heated and / or pressurized from the upper surface side of the releasable substrate sheet 21 and adhered. By peeling the peelable substrate sheet 21,
The composite thermosensitive recording layer is transferred onto the substrate 12.

In the above, any of the above-described composite thermosensitive recording layers other than those described above may be provided on the releasable surface of the releasable substrate sheet. The adhesive layer 7 is preferably laminated for industrial reasons. However, an adhesive can be applied at the time of transfer, or the adhesive layer 7 is previously laminated on the adherend. In some cases, it can be omitted. Various layers can be interposed between the releasable substrate sheet and the layer to be transferred in the structure of the transfer sheet. For example, when the releasability between the substrate sheet and the composite thermosensitive recording layer is poor, a releasable layer is laminated on the substrate sheet to impart releasability. This releasable layer remains on the substrate sheet side during transfer.

On the most releasable substrate sheet side of the composite heat-sensitive recording layer 1, a release layer for facilitating release from the substrate sheet 21 or the release layer may be laminated. Due to the presence, between the release layer and the base sheet of the transfer sheet, the adhesion between the release layer and the release layer when the release layer is interposed, while maintaining an appropriate level, and at the time of transfer , So that they can be separated smoothly. When the protective layer 8 is laminated, a release agent may be contained in the protective layer 8 so that the protective layer 8 can also serve as the release layer.

FIG. 6 shows an example of the type of label. FIG. 6 (a) shows the label on the lower surface of the transparent base material sheet 32, the reversible thermosensitive recording layer 4, the transparent heat insulating layer 3, and the near side. Infrared absorbing layer 5, heat-sensitive destruction layer 2, coloring layer 6, and adhesive layer 7
Is a label 31 composed of a laminated body sequentially laminated downward. The label 31 is placed on the substrate 12 as an adherend with the adhesive layer 7 side as the adherend side, and is heated and / or pressed from the upper surface side of the transparent substrate sheet 32 to be adhered. A composite thermosensitive recording layer is laminated on the material 12. In the label 31, as the composite thermosensitive recording layer laminated on the lower surface of the transparent base material sheet 32, any of the composite thermosensitive recording layers described above may be used.

In the label 31 described with reference to FIG. 6A, since the transparent base sheet 32 is the uppermost layer, thermal recording or thermal erasure is performed on the reversible thermosensitive recording layer 4 by contact with the thermal head. At the time of performing, there is a possibility of causing a decrease in sensitivity or bleeding. As the transparent base sheet 32, a very thin material having a thickness of preferably 6 μm or less is used.
In the label shown in FIG. 6 (b), the transparent heat insulating layer 3 in FIG. 6 (a) is replaced by this transparent base sheet 32. If necessary, the protective layer 8 may be laminated in this way. You may omit it. In this case, the transparent base sheet 32
Is not in the uppermost layer, so that the recording sensitivity to the reversible thermosensitive recording layer 4 does not decrease.

Transparent substrate sheet 32 in label 31
Can be further laminated on the lower layer, and the transparent substrate sheet 32 can be laminated on the upper surface or the lower surface where the heat-sensitive destruction layer 2 and the near infrared absorbing layer 5 are laminated. Laminating a transparent substrate sheet between the heat-sensitive destruction layer 2 and the near infrared absorbing layer 5 is avoided. When the heat-sensitive destruction layer 2 has a colored layer 6 on the lower surface, a transparent substrate sheet 32 may be laminated between the heat-sensitive destruction layer 2 and the colored layer 6. From the viewpoint of properties, it is preferable that the heat-sensitive destruction layer 2 and the colored layer 6 are not laminated. Therefore, it is preferable that the heat-sensitive destruction layer 2 and the colored layer 6 are laminated on the upper surface or the lower surface. When the composite heat-insulating layer of the label 31 has the adhesive layer 7 on the lowermost surface, the transparent base sheet 32 can be laminated immediately above the adhesive layer 7.

As the reversible thermosensitive coloring layer 6, a layer in which an organic low-molecular compound is dispersed in a resin matrix is used. The resin is transparent, mechanically and chemically stable, and has a film-forming property. Are preferable, and the organic low-molecular-weight compound is a compound that changes to polycrystal by heat, and preferably has a melting point of 50 ° C to 150 ° C.

As the resin for the resin matrix of the reversible thermosensitive coloring layer 6, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl acetate resin, polyester resin, polyamide resin, acrylic resin or methacrylic resin,
Silicone resins, phenol resins, epoxy resins, vinyl chloride / vinyl acetate copolymers, vinyl chloride / acrylate copolymers, vinylidene chloride / vinyl chloride copolymers, vinylidene chloride-acrylonitrile copolymers and the like are used.

The low-molecular organic compounds dispersed in the resin matrix in the reversible thermosensitive coloring layer 6 include lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, and the like.
Higher fatty acids such as palmitic acid, stearic acid, behenic acid, nonadecanoic acid, alginic acid, or oleic acid;
A higher fatty acid ester such as methyl stearate, tetradecyl stearate, octadecyl stearate, octadecyl laurate, octadecyl palmitate, or dodecyl behenate, or a higher alcohol or a derivative thereof is used.

As the reversible thermosensitive coloring layer 6, a combination of a leuco dye which is an electron donating substance and a developer which is electron-accepting is used as in the case of forming the irreversible thermosensitive coloring layer. Can also be used. As the leuco dye in this case, a phthalide-based compound, an azaphthalide-based compound, a fluoran-based compound, a phenothiazine-based compound, or a leuco-auramine-based compound is used. As the developer, an organic phosphoric acid compound having a long-chain aliphatic hydrocarbon group, an aliphatic carboxylic acid compound, or a phenol compound is used.

The transparent heat-insulating layer 3 comprises a transparent resin, and preferably a pigment dispersed in the transparent resin. These do not hinder the coloring of the reversible thermosensitive recording layer and desirably do not have hiding properties. The transparent heat-insulating layer 3 is preferably thicker for the purpose of thermally insulating between the near-infrared absorbing layer and the reversible thermosensitive recording layer. Since the thickness exceeds the upper limit of the thickness and does not match the clearance set in the reader, it is preferable that the thickness is thinner. In practice, the thickness is preferably 1 to 3 μm.

As the transparent resin, polyvinyl alcohol, starch, modified starch, methylcellulose, hydroxyethylcellulose, gelatin, casein, alkylene / maleic anhydride copolymer, polyvinylpyrrolidone, acrylamide water-soluble resin, styrene / butadiene copolymer emulsion , Urea resin, melamine resin, amide resin, polyurethane resin and the like.
As pigments, calcium carbonate, aluminum hydroxide,
Examples include silicate, zeolite, silica, kaolin, clay, and urea formalin resin.

The near-infrared absorbing layer 5 contains a resin binder
It contains a light absorbing agent for converting near-infrared light into heat, and is located below the reversible thermosensitive recording layer 4, so that the visibility of recording on the reversible thermosensitive recording layer 4 is not hindered. Even if it is colorless or colored, it is desirably light.

The light absorbing agent constituting the near-infrared absorbing layer 5 includes, for example, phthalocyanine, naphthalocyanine, bisthiourea compounds, squarylium, azurenium, triphenylamine, trisazo, diphenylmethane, and the like. Triphenylmethane, quinone,
Naphthoquinone-based, anthraquinone-based, azo-based, immonium-based, diimmonium-based, metal complex-based, metal sulfide and thiourea-based compounds, or phosphorus compounds and copper compounds, and the like.One or more of these are used. I do.

The heat-sensitive destruction layer 2 generates heat by the photothermal conversion effect in the near-infrared absorptive layer 5 by irradiation with near-infrared laser light or the like, and the portion to which the heat is transferred is melted or evaporated. The color of the base such as the colored layer can be visually recognized. Specifically, the heat-sensitive destruction layer 2
A metal thin film having a relatively low melting point, such as Te, Sn, In, Bi, Pb, Zn, or Al, or an alloy of these metals, or a compound containing these metals;
For example, a thin film made of Te-C or the like may be used.

The thin film made of these materials is formed by a vacuum evaporation method, a sputtering method, a plating method, or the like. The thickness of the thin film is 10 nm to 1 μm, and more preferably 50 to 100 nm, although it depends on the material so that sufficient destruction by heat occurs. Note that an anchor layer may be laminated above and below the heat-sensitive destruction layer 2. The lamination of the anchor layer improves the adhesion strength between the layers sandwiching the anchor layer, and also facilitates the destruction of the heat-sensitive destruction layer 2 due to melting or the like, thereby improving the printing sensitivity. The anchor layer is formed of, for example, a thermoplastic resin such as a polyester resin, a vinyl chloride / vinyl acetate copolymer, or a polyvinyl chloride resin, or a thermosetting resin such as a polyurethane resin, and has a thickness of 1 μm.
About m is good.

The protective layer 8 is laminated as necessary. Since the protective layer 8 is laminated on the outermost surface, the surface of the composite thermosensitive recording layer on the adherend such as a card may have friction during use. It is intended to prevent abrasion and thermal deformation when subjected to heat, etc.It has chemical resistance, water resistance, abrasion resistance, etc., and to make the lower layer transparent It is preferable to have transparency.

The protective layer 8 is made of the binder resin described above, and is also made of a thermosetting resin or an ionizing radiation plug for the purpose of enhancing the abrasion resistance, chemical resistance, or contamination resistance of the surface. A curable resin (ultraviolet curable magnetic recording layer or electron beam curable resin) may be used, and the thickness is about 0.1 to 10 μm. Note that an anchor layer may be interposed between the layers to secure the adhesion between the protective layer 8 and the lower layer (for example, the reversible thermosensitive recording layer).

The coloring layer 6 is laminated on the lower layer of the heat-sensitive destruction layer 2 and can be seen from the opening formed by the recording of the heat-sensitive destruction layer 2. To obtain a sufficient amount, a colorant of a dye or a pigment is selected and used, and a toned coating composition or an ink composition is used, and roll coating, gravure coating, or knife edge coating, which is a known coating method, is used. Alternatively, it is formed by gravure printing or offset printing, which is a known printing method. When the colorant in the coloring layer 6 is selected from those having absorption in the near-infrared region, it is not absorbed in the near-infrared region after coloring as a dye precursor in the upper reversible thermosensitive recording layer. By selecting one, the recorded content on the heat-sensitive destruction layer cannot be seen, but can be read by a reader using near infrared rays.

The coating composition or ink composition for this purpose is usually prepared by adding a binder, a colorant comprising a pigment or / and a dye, a solvent or a dispersant, and a coating composition or ink composition. It is obtained by mixing and kneading additives usually added.

Examples of the binder of the coating composition or the ink composition include cellulose derivatives such as ethyl cellulose, ethyl hydroxyethyl cellulose, cellulose acetate propionate, and cellulose acetate; styrene resins such as polystyrene and poly-α-methylstyrene; Acrylic resin such as copolymer resin, polymethyl methacrylate, polyethyl methacrylate, polyethyl acrylate, or polybutyl acrylate or methacrylic resin alone or copolymer, rosin, rosin-modified phenolic resin, or polymerized rosin A rosin ester resin, a polyvinyl acetate resin, a coumarone resin, a vinyl toluene resin, a vinyl chloride resin, a polyester resin, a polyurethane resin, or a butyral resin is exemplified.

The colored layer 6 is made of a magnetic recording material containing a magnetic material powder.
It may be a recording layer. Magnetic powder is generally brown
Because it is color. As the magnetic material powder, γ-Fe_TwoO_Three,
Co deposition-Fe_TwoO_Three, Fe_ThreeO_Four, CrO _Two, Fe, Fe
-Cr, Fe-Co, Co-Cr, Co-Ni, Mn-
Al, Ba ferrite or Sr ferrite
Anything you know can be used.

When the colored layer 6 is a magnetic recording layer containing a magnetic material powder, the binder may be a butyral resin, a vinyl chloride / vinyl acetate copolymer, a polyurethane resin, a polyester resin, a cellulose resin, an acrylic resin, Alternatively, a styrene / maleic acid copolymer resin can be used. If necessary, a nitrile rubber or a urethane elastomer is added.

The formation of the magnetic recording layer as the colored layer 6 is carried out by using a solvent or dispersant, a surfactant, a silane coupling agent, a plasticizer, a wax, silicone oil, carbon Gravure coating, roll coating, knife edge coating, etc. using a paint composition or ink composition obtained by adding and dispersing other pigments, etc .; 1 to 100 μm, more preferably 5 to 20 μm
Thickness.

The adhesive layer 7 has excellent adhesion to the composite thermosensitive recording layer 1 of the present invention, and is used for the substrate 1 of an adherend such as a card.
It is constituted by using an adhesive selected in consideration of the adhesiveness to the second. Specific adhesives include vinyl chloride resin, vinyl acetate resin, vinyl chloride-vinyl acetate copolymer resin,
Acrylic resin, polyester resin, polyurethane resin, polyamide resin, rubber modified products and the like,
Appropriate ones can be selected from these, and these can be used singly or in a mixture of two or more kinds, and if necessary, a hard resin, a plasticizer, and other additives may be used. Can be.

In the present invention, when the composite thermosensitive recording layer 1 is used in the form of a transfer sheet, the releasable base sheet 22 may be a polyethylene terephthalate resin film, a polypropylene resin film, a polycarbonate film, a polyamide resin film, or the like. The heat-resistant resin film is used, and if necessary, a coating film of a silicone resin or a wax-containing coating film is laminated to impart releasability to the surface.

In the present invention, the composite thermosensitive recording layer 1
As a transparent base sheet 32 when used in the form of a label, the heat-resistant resin film mentioned as a material of the above-mentioned peelable base sheet 22 does not particularly impart releasability, but rather is necessary. According to the above, an anchor agent may be laminated on the upper surface and / or the lower surface of the transparent base material sheet 32 and used.

The composite thermosensitive recording layer 1 and the thermosensitive recording medium 1 of the present invention
1. Thermal recording or thermal erasure is performed on the heat-sensitive recording layer transfer sheet 21 or the heat-sensitive recording layer sticking label 31 by a method as shown in FIG. In FIG. 7, FIG.
The thermal recording medium 11 as shown in FIG.
From the side, a colored layer 6, a heat-sensitive destruction layer 2, a near-infrared absorbing layer 5,
The transparent heat-insulating layer 3 and the reversible thermosensitive recording layer 4 are sequentially laminated, and the protective layer is omitted.

As shown on the left side of FIG. 7, laser light such as near-infrared laser light 41 emitted from a near-infrared laser light source is applied to a necessary portion of the near-infrared absorbing layer 5 by using a lens 42. The light-collecting portion 43 is irradiated with the light, and the light-collecting portion 5a generates heat. At the position adjacent to the light-collecting portion 5a, the metal thin film or the like of the heat-sensitive destruction layer 2 is melted and removed from the position. Then, a hole 2a is formed and thermal destruction recording is performed by the optical contact method. In the example of FIG. 7, since the coloring layer 6 is provided below the opening 2a, when viewed from the top, the color of the coloring layer 6 viewed from the opening 2a and the color of the material of the heat-sensitive destruction layer 2 are different. The visibility increases the visibility of the opening 2a due to the contrast.

The heat-sensitive destruction layer 2 by this near-infrared laser beam
In recording on the near-infrared laser beam 41, the near-infrared laser beam 41 is focused on the near-infrared absorbing layer. When passing through the reversible thermosensitive recording layer 4, the near-infrared laser beam 41 is not absorbed and no heat is generated, so that the reversible thermosensitive recording layer 4 is not colored. Even if heat is generated in the light-collecting portion 5a of the near-infrared absorbing layer 5, a large amount of heat is applied to the reversible thermosensitive recording layer 4 from below because there is a transparent heat insulating layer between the reversible thermosensitive recording layer 4 and the reversible thermosensitive recording layer 4. Is prevented from being transmitted, and again, the reversible thermosensitive recording layer 4 does not develop color.

[0051] Also, as depicted on the right side of FIG. 7, is brought into contact with the thermal head 51 to the reversible thermosensitive recording layer 4, by heating at a recording temperature above T ₁ of the temperature at the contact portion, sensitive reversibly The thermal recording layer 4 becomes cloudy, and a print record is formed. Similarly, lower than the recording temperature T _1, and after heating to a higher temperature T ₂ ambient temperature, the whole when cooled becomes transparent, the printing unit is erased. Thus, thermal recording and thermal erasure are performed. In the thermal recording or thermal erasure on the reversible thermosensitive recording layer 4 by the thermal head, heat is generated from the thermal head 51. The influence of the heat on the thermosensitive destruction layer 2 is caused by the lower layer of the reversible thermosensitive recording layer 4. Prevented by some transparent insulating layer. In this case, the lower near-infrared absorbing layer 5 also functions as a heat insulating layer in relation to the thermal head.

Therefore, the thermal destructive recording of the optical contact system by the near infrared laser beam and the thermal recording or erasing of the contact system by the thermal head can be performed independently.
Unless the contact-type recording is performed in a solid manner (uniform and uniform), both recordings appear to overlap. Also, if the contact-type recording is performed in a solid pattern, the non-contact-type recording will be covered, so especially if the contact-type recording is dark, regardless of the color hue of the lower layer, the lower-layer non-contact recording Can be hidden. In the above, non-contact recording and contact recording or contact erasure are
It does not matter which one comes first or after. The heat-sensitive destruction layer can be configured so that recording can be performed by irradiating a near-infrared laser beam from below. Therefore, it is better to perform non-contact thermal destruction recording using near-infrared laser light or the like.

As described above, even when the thermal destruction record of the lower layer cannot be visually recognized, it is possible to perform reading using infrared rays. If a material is selected as the upper layer of the reversible thermosensitive recording layer 4 so as to visually hide the lower layer and prevent absorption in the near-infrared region after color development, the recording of the lower heat-sensitive destruction layer 2 can be improved. This is because reading can be performed by infrared rays. In addition,
As described above, when the coloring layer 6 is involved, and when the coloring layer 6 selectively contains a coloring agent having absorption in the near infrared region, reading in the near infrared region is more reliable. become.

As a preferred example of reading using near-infrared light, a fine bar code, password, ID number, etc. are recorded in the lower heat-sensitive destruction layer 2 by a semiconductor laser or the like in a non-contact manner. If the contact-type recording is performed on the reversible thermosensitive recording layer 4 in a solid manner,
A non-contact type record can be read only by a reader using near-infrared light as a light source. If the solid recording is first performed on the upper reversible thermosensitive recording layer 4 and then the recording is performed on the lower heat-sensitive destruction layer 2, the recorded contents cannot be seen even in the non-contact recording. Therefore, it is more preferable in terms of security.

[0055]

(Example 1) A thermosensitive recording medium 11 having a layer structure almost similar to that shown in FIG. 4B was produced as follows. 188 μm thick polyethylene terephthalate resin film (E-20, manufactured by Toray Industries, Inc.) as the base material 12
Is prepared, and the colored layer 6, the heat-sensitive destruction layer 2, the near-infrared absorbing layer 5, the transparent heat-insulating layer 3, the reversible thermosensitive recording layer 4, and the protective layer 8 are sequentially laminated in the following manner. did. However, the heat-sensitive destruction layer 2 was formed by a vacuum deposition method, and the other layers were formed by a gravure printing method. The thickness of each layer is the thickness after drying.

The colored layer 6 was formed to a thickness of 2 μm using black ink using a polyester resin containing carbon black as a binder. As the heat-sensitive destruction layer 2, an anchor coat agent using a vinyl chloride / vinyl acetate copolymer as a binder is used to form a layer having a thickness of 0.1 mm on the colored layer 6.
After forming an anchor layer of 5 μm, S
n thin films were formed. The near-infrared absorbing layer 5 is formed using a composition in which a near-infrared light absorbing substance (manufactured by ICI, product number: S110510) is mixed with a 10% aqueous solution of a polyvinyl alcohol resin and an isocyanate-based curing agent, and has a thickness of 2 μm.
m. The transparent heat-insulating layer 3 was formed using a 10% aqueous solution of a polyvinyl alcohol resin and had a thickness of 2 μm.
The reversible thermosensitive recording layer 4 is composed of stearic acid; 8 parts (“parts” are based on mass including the following), a vinyl chloride / vinyl acetate / phosphate ester copolymer; 20 parts, and a solvent (tetrahydrofuran) A film having a thickness of 10 μm was formed using a composition in which 160 parts were mixed. The protective layer 8 was formed to a thickness of 4 μm using a urethane acrylate-based ultraviolet curable resin.

A semiconductor laser beam having a wavelength of 780 nm was used for the obtained heat-sensitive recording medium, and the position of the objective lens was adjusted so that the focal point came in the middle of the thickness of the near-infrared absorbing layer 5. In the apertures, the lower colored layer 6 is black, and in the non-openings, the heat sensitive destruction layer 2 is made of the Sn metal color. Showed no change in color development or the like. When thermal recording and thermal erasing were performed on the reversible thermosensitive recording layer 4 using a thermal head, good printing and erasing could be performed.

(Example 2) The reversible thermosensitive recording layer 4 was coated with a fluoran leuco dye (2-anilino-3-methyl-6-).
Dibutylaminofluoran; 10 parts, developer (p- (γ
-Octadecylsulfonylbutanoylamino) phenoxyacetic acid); 20 parts, a binder resin (vinyl chloride / vinyl acetate copolymer); 35 parts, and a solvent (methyl ethyl ketone); Was set to 6 μm. The composition is prepared using a sand mill so that the average particle size of the dye and the developer is 0.3 mm, and the visible light of the coating film or the near infrared light is transmitted as much as possible. I did not disturb.

In the obtained thermosensitive recording medium, recording on the thermosensitive destruction layer 2 and the reversible thermosensitive recording layer 4 can be performed without affecting the other layer, similarly to that obtained in Example 1. Was. When a barcode was recorded on the heat-sensitive destruction layer 2 and solid printing was performed on the reversible heat-sensitive recording layer 4 to uniformly develop black, the barcode was completely hidden under visual observation. . When an infrared barcode reader was used in this state, it was possible to read a barcode that was apparently hidden.

[0060]

According to the first aspect of the present invention, since the heat-sensitive destruction layer and the reversible heat-sensitive recording layer are separated by the transparent heat-insulating layer, the recording on the heat-sensitive destruction layer or the reversible heat-sensitive recording layer is performed. In the case of thermal recording or thermal erasure on a layer, it is possible to provide a composite thermosensitive recording layer capable of performing recording or erasure while avoiding the influence on other layers. In addition, since the near-infrared absorbing layer is interposed between the heat-sensitive destruction layer and the transparent heat-insulating layer, the near-infrared absorbing layer converts light to heat and transmits it to the heat-sensitive destruction layer, thereby reducing the heat sensitivity. A composite thermosensitive recording layer capable of performing non-contact thermal destruction recording on a fracture layer can be provided. According to the second aspect of the present invention, in addition to the effect of the first aspect of the present invention, since the coloring layer is laminated on the heat-sensitive destruction layer on the side opposite to the transparent heat-insulating layer, the recording is performed on the heat-sensitive destruction layer. Since the colored layer can be seen through the opening, a composite heat-sensitive recording layer can be provided which can enhance visibility by comparing the hue with the heat-sensitive destruction layer. According to the invention of claim 3, in addition to the effect of the invention of claim 1 or 2,
It is possible to provide a composite thermosensitive recording layer in which the color of the reversible thermosensitive recording layer is uniformly and uniformly colored so that the lower layer is apparently concealed and the information of the lower layer can be read by near infrared rays. According to the invention of claim 4, in addition to the effect of any one of claims 1 to 3,
Since the adhesive layer is laminated on the exposed surface of the composite heat-sensitive recording layer on the heat-sensitive destruction layer side, it is possible to provide a composite heat-sensitive recording layer that can be easily attached to various adherends. According to the fifth aspect of the invention, it is possible to provide a thermosensitive recording medium in which the composite thermosensitive recording layer having the effects of any one of the first to fourth aspects is laminated on a substrate. According to the invention of claim 6, the composite thermosensitive recording layer having the effect of any one of claims 1 to 4 is laminated on the releasable surface of the transfer sheet and applied by transfer to various adherends. Can provide an easy transfer sheet. According to the invention of claim 7, the composite thermosensitive recording layer having the effect of any one of claims 1 to 4 is laminated on a transparent substrate sheet, and can be easily applied by sticking to various adherends. We can provide labels. According to the invention of claim 8, since the transparent substrate sheet has a structure in which the transparent heat-insulating layer is replaced, the label has the same effect as that of claim 7, and there is no decrease in the sensitivity of the reversible thermosensitive recording layer. Can be provided. According to the ninth aspect, the first aspect is provided.
The heat-sensitive destruction layer of the composite heat-sensitive recording layer of any one of claims 1 to 4, the heat-sensitive recording material of claim 5, the heat-sensitive recording layer transfer sheet of claim 6, or the heat-sensitive recording layer sticking label of claim 7 or 8. By performing non-contact thermal recording with a near-infrared laser beam and thermal recording and / or erasing with a thermal head using a thermal head, the reversible thermosensitive recording layer and the thermal destruction layer are superposed. Recording on each layer without affecting each other,
Alternatively, a recording method capable of performing recording and erasing can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a composite thermosensitive recording layer.

FIG. 2 is a cross-sectional view of a composite thermosensitive recording layer with a coloring layer.

FIG. 3 is a cross-sectional view of a composite thermosensitive recording layer including a protective layer and an adhesive layer.

FIG. 4 is a sectional view of a thermosensitive recording medium.

FIG. 5 is a cross-sectional view of a heat-sensitive recording layer transfer sheet.

FIG. 6 is a cross-sectional view of a label for attaching a thermosensitive recording layer.

FIG. 7 is a sectional view showing a state of recording on a thermosensitive recording medium.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 composite heat-sensitive recording layer 2 heat-sensitive destruction layer 3 transparent heat-insulating layer 4 reversible heat-sensitive recording layer 5 near-infrared absorbing layer 6 colored layer 7 adhesive layer 8 protective layer 11 heat-sensitive recording material 12 base material (adherend) 21 Heat-sensitive recording layer transfer sheet 22 Peelable base material sheet 31 Heat-sensitive recording layer sticking sheet 32 Transparent base material sheet 41 Near-infrared laser beam 42 Lens 51 Thermal head

Claims (9)

[Claims] 1. A composite heat-sensitive recording layer comprising: a heat-sensitive layer; a near-infrared absorbing layer; a transparent heat-insulating layer; 2. The composite thermosensitive recording layer according to claim 1, wherein a colored layer is laminated on the side of the thermosensitive destruction layer opposite to the near infrared absorbing layer. 3. The composite thermosensitive recording layer according to claim 1, wherein the reversible thermosensitive recording layer contains a dye precursor that does not absorb in the near infrared region after color development. 4. The composite heat-sensitive recording layer according to claim 1, wherein an adhesive layer is laminated on an exposed surface of the composite heat-sensitive recording layer on the heat-sensitive destruction layer side. 5. The method according to claim 1, wherein at least a part of the substrate is provided.
5. A heat-sensitive recording material, wherein the heat-sensitive destruction layer side of the composite heat-sensitive recording layer according to any one of 4) is stacked facing the base material side. 6. The transfer of a thermosensitive recording layer, wherein the reversible thermosensitive recording layer side of the composite thermosensitive recording layer according to any one of claims 1 to 4 is laminated on a releasable surface of a releasable substrate sheet. Sheet. 7. A label for attaching a thermosensitive recording layer, wherein the reversible thermosensitive recording layer side of the composite thermosensitive recording layer according to claim 1 is laminated on a transparent base sheet. 8. A label for adhering a heat-sensitive recording layer, which has the requirements of the composite heat-sensitive recording layer according to any one of claims 1 to 4, and wherein the transparent heat-insulating layer is a transparent substrate sheet. 9. The heat-sensitive recording layer according to any one of claims 1 to 4, the heat-sensitive recording medium according to claim 5, the transfer sheet for heat-sensitive recording layer according to claim 6, or the heat-sensitive recording layer according to claim 7 or 8. For the near infrared absorbing layer of the label for attachment,
Irradiate near infrared laser light to generate heat by photothermal conversion,
A recording method comprising: performing heat-sensitive destruction recording on a heat-sensitive destruction layer by generated heat; and performing heat recording and / or heat erasure by bringing a heated recording means into contact with the reversible thermosensitive recording layer.