JP2741471B2 - Thermal recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating method, for example, used as a printout for a computer, a recording paper for facsimile reception and the like, a ticket or a ticket such as a boarding pass, a label, a card, etc., particularly a prepaid card. The present invention relates to a heat-sensitive recording medium in which printing such as printing is performed by a physical change.

[0002]

2. Description of the Related Art In general, a so-called thermosensitive recording system in which an image display of characters or the like is obtained by utilizing physical or chemical change of a substance by thermal energy such as heating or the like, noise is generated at the time of recording. It is widely used not only for copiers, but also for computer printouts, facsimile reception records, tickets, labels, and various types of cards. ing. As a heat-sensitive recording medium used in this heat-sensitive recording method, for example, a heat-sensitive recording medium using a leuco body such as a fluoran dye as a coloring agent is widely used because of its excellent heat sensitivity. However, this recording medium easily develops color even by pressure, an organic solvent such as alcohol, and has problems in light resistance, heat resistance, water resistance, and storage stability of print records.

For this reason, for example, a thermosensitive recording medium using a metal thin film layer as a recording layer has been put to practical use. This thermosensitive recording medium destroys the metal thin film layer based on a pattern of an image to be recorded by a heat source such as a thermal head, a laser beam, or a flash light, and removes a colored layer provided below the metal thin film layer. By exposing,
An image is formed. Therefore, since the image display such as printing is formed by the contour of the metal thin film layer, its light resistance, heat resistance, water resistance and storage stability of the printed record are based on the thermosensitive recording medium using the above-described dye as a coloring agent. Excellent compared to.

A thermal recording medium using a metal thin film layer is used for a prepaid card, a ticket, a label, and the like. Therefore, in practical use, a physical stimulus such as friction and scratching of the metal thin film layer, acid, alkali, It is necessary to provide a protective layer as an uppermost layer in order to protect from chemicals such as alcohol. It is generally known that the protective layer contains a heat-resistant resin such as an acrylic resin or an epoxy resin and contains an appropriate amount of an inorganic or organic pigment and a lubricant such as wax or silicone. Further, JP-A-59-199284 and JP-A-Hei 2
JP-A-62287 and the like also disclose a technique in which a protective layer has a multi-layer structure, and the functions of surface strength and adhesion to a medium are separated to improve the above required characteristics.

[0005]

However, even in such a heat-sensitive recording medium provided with a protective layer, even when the card is used as a prepaid card, or when the card is erroneously washed, etc. There is a problem that the thin film layer is peeled off. Further, in a field of application as a so-called magnetic card having a magnetic recording layer, there is a problem that the metal thin film layer is peeled or scraped due to high-speed conveyance seen in an automatic ticket gate and the like, and print information is lost. However, there is a problem that the security of the card is reduced. The present invention has been made in view of the above circumstances, and its object is to provide an excellent thermosensitive recording that is resistant to physical stimuli such as friction and scratching, and is stable against chemicals such as acids, alkalis and alcohols. To provide a medium.

[0006]

Means for Solving the Problems A first invention of the present invention is:
On a support, the colored layer, the anchor layer, the thermosensitive recording medium comprising successively laminating a metal thin film layer and the protective layer, the anchor layer is maleic acid, at least one vinyl acetate chloride selected from phosphoric acid ester A copolymer having a glass transition temperature of 30 ° C. or higher containing vinyl as a copolymer component, and the copolymer having a total solid content of 20% in the anchor layer.
It is a heat-sensitive recording medium characterized in that the content is at least 10% by weight.

Further, the second invention, on a support, an anchor layer containing a coloring agent, heat-sensitive recording medium comprising successively laminating a metal thin film layer and the protective layer, the anchor layer is maleic acid, phosphoric acid esters A copolymer having at least one selected from the group consisting of vinyl chloride and vinyl acetate and having a glass transition temperature of 30 ° C. or higher, wherein the copolymer has a total solid content ratio of the anchor layer. A thermosensitive recording medium, characterized in that the content is 20% by weight or more.

[0008] In the present invention, the anchor layer
Acid, at least one glass transition temperature obtained by polymerizing the vinyl chloride and vinyl acetate as an essential copolymerization component selected from phosphoric acid ester (hereinafter abbreviated as "Tg") of 3
The metal thin film layer is firmly adhered on the anchor layer by containing the copolymer having a temperature of 0 ° C. or higher and containing the copolymer in the total solid content ratio of the anchor layer of 20% by weight or higher. Therefore, peeling of the metal thin film layer from strong physical impact can be prevented, and good chemical resistance can be obtained, preventing chemicals such as saline, acid, alkali and the like from penetrating from the support side and attacking the metal thin film layer. be able to. If the content of the specific copolymer in the anchor layer is less than 20% by weight, the adhesiveness to the metal thin film layer and the chemical resistance of the recording medium are deteriorated.

The copolymer used in the anchor layer contains, as essential components, three components of vinyl chloride and vinyl acetate as described above, and at least one selected from maleic acid and phosphoric acid ester. Things. Here, examples of the phosphoric ester include a monoalkyl ester, a dialkyl ester, and a trialkyl ester, and among them, a lower alkyl ester having 1 to 5 carbon atoms is preferable. The copolymerization ratio of the three components in the copolymer used in the present invention is not particularly limited, but in order to obtain better adhesion, a copolymer selected from vinyl chloride: vinyl acetate: the above specific compound is used. It is preferable that the polymerization component has a copolymer composition (weight ratio) in the range of 50 to 99: 1 to 40: 0.1 to 20. In addition,
The copolymer used in the present invention may be a copolymer obtained by adding a fourth polymerizable monomer in addition to the above three components. In this case, the fourth comonomer ratio is preferably 20% or less. In the present invention, it is necessary that the specific copolymer has a Tg of 30 ° C. or higher, and the Tg is 30 ° C.
If the temperature is lower than ℃, sufficient chemical resistance cannot be obtained. Note that Tg in the present invention is based on the DSC method. As specific examples of the copolymer to be blended in the anchor layer,
Vinyl chloride - vinyl acetate - maleic acid copolymer, vinyl chloride - vinyl acetate - phosphate ester copolymers, vinyl chloride - vinyl acetate - acrylamido - maleic acid copolymer.

The anchor layer constituting the heat-sensitive recording material of the present invention includes an acrylic resin such as polystyrene and polymethacryl methacrylate, a cellulose resin such as cellulose acetate propionate, a vinyl chloride-vinyl acetate copolymer and a polyester resin. Resins, polyurethane resins, epoxy resins, amino alkyd resins, copolymers of these resins, and the like can be appropriately mixed and used. Also,
In order to control thermoplasticity, it is possible to add a heat-meltable substance such as a plasticizer or wax, and to add a curing agent to impart a certain solvent resistance and facilitate the formation of a metal thin film layer. May be. Further, in order to control the glossiness of the metal thin film layer, inorganic pigments such as silica, talc, clay, zeolite, calcium carbonate, and magnesium hydroxide, and organic pigments such as acrylic resin, polystyrene, epoxy resin, and phenol resin alone are used. Alternatively, two or more kinds may be added. In the case of the anchor layer containing a coloring agent as in the second invention, a coloring agent used for a coloring layer described later can be used as appropriate.

The anchor layer in the present invention has the above-mentioned composition. With such a composition, not only strong adhesion with the metal thin film layer can be obtained, but also adhesion with the coloring layer, the support and the like. Because it is excellent, it is possible to form a strongly integrated thermal recording medium, and at the time of thermal recording, by promoting the destruction of the metal thin film layer,
It has the function of improving thermal energy sensitivity. To form such an anchor layer, a paint or ink having the composition described above is used, and a wire bar method, a roll coating method, a coating method such as a knife edge method, or a printing method such as a gravure method, an offset method, or a flexo method. Can be formed. The thickness of the anchor layer is not particularly limited, but is usually about 1 to 10 μm, preferably 1 to 5 μm. If a magnetic recording layer is provided between the anchor layer and the support, a thicker anchor layer may interfere with reading and writing of magnetic recording. Therefore, it is necessary to appropriately adjust the thickness of the anchor layer.

As the support used in the present invention, a conventionally known film, paper, glass, metal or the like can be used as it is. Specific examples thereof include polyethylene terephthalate (PET), polyimide, polyether,
Various heat-resistant resin films such as polycarbonate, polysulfone, cellophane, and aromatic polyamide, and condenser paper, sulfuric acid paper, art paper, name paper, coated paper,
Paper substrates such as laminated paper and polyethylene synthetic paper, glass substrates such as quartz, and metal substrates such as aluminum can be suitably used.

The coloring layer is for displaying an image of a desired color tone when the metal thin film layer is exposed by being heated according to the formation of an image pattern. Examples of the coloring layer include ethyl cellulose, hydroxyethyl cellulose, and cellulose acetate. Propionate, cellulose derivatives such as cellulose acetate, polystyrene, styrene resin or styrene copolymer resin such as poly-α-methylstyrene,
Acrylic resin such as polybutyl methacrylate or methacrylic resin alone or copolymerized resin, rosin, rosin modified phenol resin, rosin modified maleic resin, rosin ester resin such as polymerized rosin, polyvinyl acetate resin, cumarone resin, vinyl toluene resin Various organic and inorganic coloring pigments or coloring dyes, depending on the color to be colored, to resins such as vinyl chloride resin, polyester resin, polyurethane resin, butyral resin, epoxy resin, or binders such as copolymers of these resins Add a coloring agent such as a plasticizer, a stabilizer, a wax, a curing agent, and a dispersant as needed, and use a color paint or ink prepared by sufficiently kneading with a solvent or a diluent. Coating method such as wire bar method, roll coating method, knife edge method or Labia method, offset method, is formed by a printing method flexographic method.

As the colorant used in the present invention, pigments, dyes and the like can be appropriately selected.
Examples of cyan dyes include Diaceriton Fast Brilliant Blue R (manufactured by Mitsubishi Kasei Co., Ltd., trade name) and Kayaron Polyester Blue B-SF Conc (trade name, manufactured by Nippon Kayaku Co., Ltd.). Tonfast Red R (manufactured by Mitsubishi Kasei Corporation, trade name), Kayaron Polyester Pink RCL-E (manufactured by Nippon Kayaku Co., Ltd., trade name), etc.
Examples of the yellow color dye include Kayalon polyester light yellow 5G-S (trade name, manufactured by Nippon Kayaku Co., Ltd.) and Eizen Spiro Yellow GRH (trade name, manufactured by Hodogaya Chemical Co., Ltd.). Also, as a cyan pigment, such as Cerulean blue, phthalocyanine blue, magenta color pigments such as brilliant carmine, arzaline lake, yellow pigments such as Hansa Yellow, bisazo yellow, etc., black pigments such as carbon black, graphite,
Oil black and the like can be mentioned. Further, F
Metals such as e, Ni, and Al, and metal oxides such as Fe ₂ O ₃ and SnO ₂ can also be used. The coloring dye can be selected from disperse dyes, oil-soluble dyes, acid dyes, mordant dyes, vat dyes, basic dyes and the like, which are generally used in transfer printing of textiles and thermal transfer inks. Specific examples thereof include azo, anthraquinone, nitro, styryl, naphthoquinone, quinophthalone, azomethine, coumarin, and condensed polycyclic dyes. Also,
Phosphorescent / fluorescent pigments can also be used. Note that a magnetic recording layer for magnetic recording may be provided as a colored layer as shown in FIG. 3 described later.

The metal thin film layer is made of Te, Sn, Al, Bi,
Metals such as Pb and Zn or alloys thereof, or Te
The above metal compound such as carbide can be formed on the upper surface of the anchor layer by a vacuum deposition method, a sputtering method, a CVD method, a plating method, or the like. In this case, the metal thin film layer
It preferably has a low melting point so that it can be used as a heat-sensitive recording layer, and its thickness is selected to be about 100 to 1 μm, preferably about 300 to 600 °.

The protective layer must be designed so as to physically and chemically protect the metal thin film layer and to prevent sticking and adhesion of scum during thermal recording. The protective layer in the present invention is not particularly limited because it is mainly composed of various film-forming resins, but in order to obtain better physical and chemical durability, a heat-resistant resin is used as the resin. It is preferable to use a configuration in which a lubricant and a pigment are added. As the heat-resistant resin, for example, polyester resin,
Polyurethane resin, epoxy resin, various cellulose resins, polyimide resin, polyamide resin, polyarylate resin, polycarbonate resin, phenol resin, alkyd resin, melamine resin, styrene resin, silicone resin , A thermoplastic resin comprising a fluororesin and a copolymer between these resins, a thermosetting resin, a UV-curable resin, an EB-curable resin, and the like. Those having a temperature of 50 ° C. or higher are preferred. Here, when Tg is lower than 30 ° C.,
During thermal recording, sticking may occur or abrasion resistance may decrease.

The lubricant has a function of preventing sticking with the heat-sensitive head, reducing the coefficient of friction and improving abrasion resistance, and includes waxes such as polyethylene wax, paraffin wax and microcrystalline wax. , Zinc stearate, higher fatty acid metal salts such as calcium stearate, stearamide,
Known materials such as oils and fats such as higher fatty acid amides such as behenic acid amide, silicone oil, fine powder of Teflon, and fine powder of boron nitride are used. In addition, the pigment has a function of preventing adhesion of scum to the thermal head. For example, heat-resistant inorganic pigments such as silica, calcium carbonate, magnesium hydroxide, zeolite, clay, and talc are used. The particle size of the pigment used is preferably in the range of 0.1 to 10 μm, particularly preferably 1 to 5 μm.

The protective layer as described above is formed on the metal thin film layer by the same method as the above-mentioned anchor layer. The thickness of the protective layer is preferably from 0.1 to 5 μm, particularly preferably from 1 to 2 μm in order to sufficiently exhibit the function as the protective layer and to obtain good sensitivity in thermal recording. The content of the heat-resistant resin, lubricant and pigment in the protective layer is 50
Preferably, it is -95%, 2-30% and 2-40% by weight. Here, when the content of the resin is less than 50% by weight, sufficient durability such as chemical resistance and water resistance may not be obtained. If the content of the lubricant is less than 2%, the abrasion resistance is deteriorated, and sticking occurs during thermal recording. Conversely, if the content is more than 30%, the heat resistance of the protective layer is deteriorated, and the head of the thermal head is degraded. Adhesion may increase. When the content of the pigment is less than 2%, scum adheres to the thermal head more, and when it exceeds 40%, the background density increases, the appearance deteriorates, and the thermal head is significantly worn. May occur.

Next, the thermosensitive recording medium of the present invention will be described with reference to the drawings. 1 and 2 show the basic layer structure of the thermosensitive recording medium of the present invention. FIG. 1 shows a colored layer 2, an anchor layer 3, a metal thin film layer 4, and a protective layer 5 on one side of a support 1.
Are sequentially laminated. FIG. 2 shows a structure in which the coloring layer and the anchor layer in FIG. 1 are integrated, and is provided as an anchor layer 6 containing a coloring agent.

FIGS. 3 to 6 show the layer structure of an embodiment in which the magnetic recording layer is used in combination with the thermosensitive recording medium of the present invention. FIG. 3 shows a thermosensitive recording medium having the layer structure of FIG. The magnetic recording layer 7 is provided in place of the coloring layer, and the magnetic recording layer also has a function as a coloring layer. FIG. 4 shows the thermosensitive recording medium of FIG. 3 in which an adhesive layer 8 is provided between the metal thin film layer 4 and the protective layer 5. FIG. 5 shows the thermosensitive recording medium of FIG. 1 in which a magnetic recording layer 7 is provided between the support 1 and the colored layer 2, and FIG. 6 shows the thermosensitive recording medium of FIG.
The magnetic recording layer 7 and the protective layer 9 are provided on the surface opposite to the colored layer 2 of FIG.

The magnetic recording layer provided as needed as in the embodiments of FIGS. 3 to 6 has a function of recording data and the like required according to the use as a thermosensitive magnetic recording medium. The data can be read and written by a magnetic card reading and writing device formed by a known method and having an appropriate configuration. The magnetic recording layer has a magnetic material and a binder as main components.
Iron oxide, cobalt doped γ-iron oxide, chromium oxide,
Barium ferrite, strontium ferrite, etc. are applied, and these magnetic materials are used as vinyl chloride / vinyl acetate copolymer, vinyl chloride / vinyl acetate / vinyl alcohol copolymer, polyurethane resin, polyester resin, epoxy resin, polyisocyanate resin, etc. A magnetic recording layer can be formed by applying a coating liquid dispersed in a binder together with other additives such as a pigment. Also, a plurality of magnetic layers having different magnetic properties can be laminated to form a magnetic recording layer. In addition, as shown in FIG. 3, the magnetic recording layer may be provided as a layer having a function as a colored layer instead of the colored layer. When the magnetic recording layer is provided on the side of the support opposite to the colored layer as shown in FIG. 6, it is preferable to provide the protective layer on the magnetic recording layer. In this case, the protective layer provided on the metal thin film layer can be used as the protective layer.

The adhesive layer provided as needed as shown in FIG. 4 has a function of improving the adhesion between the metal thin film layer and the protective layer, and a function of physically and chemically protecting the metal thin film layer. Have. Further, it has the function of promoting the destruction of the metal thin film layer by thermal recording and improving the thermal energy sensitivity. Specific materials for the resin used in this layer include polyester resins, polyurethane resins, acrylic resins, vinyl chloride-vinyl acetate copolymers, epoxy resins, cellulose resins, amino alkyd resins, and the like. Can be These resins can be used alone or in combination of two or more. The thickness of the adhesive layer is 0.1 to 5
μm, preferably 1-2 μm.
The range of m is good. In addition to the above resin, the adhesive layer may include, if necessary, an organic / inorganic pigment (including the coloring pigment described above), a plasticizer, a stabilizer, a curing agent, a dispersant, an organic solvent, and the like. Can be formed in the same manner as the above-mentioned anchor layer using a paint or ink prepared by sufficiently dispersing, dissolving, and mixing with a stirrer.

The heat-sensitive recording medium of the present invention having the above-mentioned constitution has excellent physical durability such as abrasion resistance, and excellent heat resistance which is not affected by chemicals such as acids, alkalis and alcohols. Although it has chemical durability such as chemical properties, in order to further obtain better recording characteristics, a pigment having an average particle size of 1 to 5 μm is contained in at least one of the anchor layer and the coloring layer. When mixed, the strong gloss of the coating layer is reduced, thereby making it easier to view the recorded image display. The average particle size of this pigment is 1μ
If it is less than m, a moderate gloss preventing effect does not appear, and if it is 10 μm or more, the surface area becomes large, so that the contact area with the heat-sensitive head becomes small, causing print blurring or missing printing. And good thermal recording characteristics cannot be obtained. Examples of the pigment include inorganic white pigments such as silica, calcium carbonate aluminum hydroxide, clay, and talc; organic transparent or white pigments such as crosslinked polystyrene, polyethylene beads, and silicone beads; lead red, ultramarine, titanium yellow. Color pigments, such as red-mouthed graphite and plastic-type fluorescent pigments, can be used.

The recording medium of the present invention can be used for recording by a thermal head, but can also be applied to heat mode recording by a laser beam. If there is, it can be applied without being particularly limited, for example, in discharge breakdown recording.

[0025]

Next, the present invention will be described in more detail by way of examples. All parts are parts by weight. Example 1 The following layers were sequentially laminated on the surface of a 188 μm thick milky white polyethylene terephthalate film support by coating or the like to prepare a thermosensitive recording medium of the present invention. 1. Colored layer: After being dried at a drying temperature of 110 ° C., a layer having the following composition was coated on a support so as to have a thickness of 3 μm and a surface smoothness of 500 seconds.

2. Anchor layer: An anchor layer having the following composition was applied at a drying temperature of 110 ° C. so that the coating amount after drying was 1.8 g / m ² .

3. Metal thin film layer: when the tin is measured by a film thickness measurement method using a quartz oscillator method by a vacuum evaporation method, 60
It vapor-deposited so that it might become 0 degree. 4. Protective layer: A protective layer was formed by applying a composition having the following composition to a thickness of 1.0 μm after drying at a drying temperature of 110 ° C.

Example 2 The following layers were sequentially laminated on the surface of a 188 μm thick milky white polyethylene terephthalate film support by coating or the like to prepare a heat-sensitive recording medium of the present invention. 1. Coloring layer: (magnetic recording layer) After dispersing the above mixture in a ball mill for 8 hours, After adding the above curing agent and further dispersing for 1 hour,
m on a milky white polyethylene terephthalate film by a solvent coating method, and orientation treatment is performed by a magnetic field orientation treatment device while the paint is not dried, dried at 100 ° C. for 5 minutes, thickness 15 μm, surface smoothness A magnetic recording layer was formed for 500 seconds.

2. Anchor layer: An anchor layer having the following composition was applied at a drying temperature of 110 ° C. so that the coating amount after drying was 1.8 g / m ² . 3. Metal thin film layer: Tin is measured by the vacuum evaporation method and the thickness is measured by the quartz crystal oscillator method.

4. Adhesive layer: An adhesive layer having the following composition was applied so as to have a thickness of 0.75 μm after drying at a drying temperature of 110 ° C. to form an adhesive layer. 5. Protective layer: A protective layer was formed by applying a composition having the following composition to a thickness of 3 μm after drying at a drying temperature of 100 ° C.

[0031]

Example 3 A heat-sensitive recording medium of the present invention was produced in the same manner as in Example 1 except that the coloring layer was not provided and the anchor layer had the following composition. . Anchor layer: An anchor layer having the following composition was applied at a drying temperature of 110 ° C. so that the coating amount after drying was 1.8 g / m ² .

Comparative Example 1 A comparative thermosensitive recording medium was prepared in the same manner as in Example 2 except that the anchor layer of Example 2 was changed as follows. Anchor layer: An anchor layer was formed by applying a composition having the following composition so as to have a thickness of 1.0 μm after drying at a drying temperature of 110 ° C.

Comparative Example 2 A comparative thermosensitive recording medium was prepared in the same manner as in Example 2 except that the anchor layer of Example 2 was changed as follows. Anchor layer: An anchor layer was formed by applying a composition having the following composition so as to have a thickness of 1.0 μm after drying at a drying temperature of 110 ° C.

Comparative Example 3 A comparative thermosensitive recording medium was prepared in the same manner as in Example 2 except that the anchor layer of Example 2 was changed as follows. Anchor layer: An anchor layer was formed by applying a composition having the following composition so as to have a thickness of 1.0 μm after drying at a drying temperature of 110 ° C.

Comparative Example 4 A comparative thermosensitive recording medium was produced in the same manner as in Example 1 except that the anchor layer of Example 1 was changed as follows. Anchor layer: The following composition having a drying temperature of 110 ° C.
The coating was performed so that the coating amount after drying was 1.8 g / m ² .

Comparative Example 5 A comparative thermosensitive recording medium was produced in the same manner as in Example 1 except that the anchor layer of Example 1 was changed as follows. Anchor layer: The following composition having a drying temperature of 110 ° C.
The coating was performed so that the coating amount after drying was 1.8 g / m ² .

The following characteristics were evaluated for Examples 1 to 3 and Comparative Examples 1 to 5 prepared as described above. (1) Recording Characteristics Print recording was performed with a thermal printing apparatus equipped with a thin-film thermal head having a dot density of 6 dots / mm with a pulse width of 2.5 ms and an applied energy of 0.6 W. The recording density and the background density were measured using a Macbeth densitometer RD-914 (visual filter). (2) Head Matching Performance Printing was performed 10,000 times continuously under the above-mentioned recording conditions, and the state of stick and scum adhesion was examined. (3) Light fastness After exposure for 6 hours with a fade meter, the discolored / faded state of the recorded portion was visually inspected. (4) Water Resistance After immersion in water at 20 ° C. for 3 days, the deterioration of the metal thin film layer and the protective layer and the peeled state were visually examined. (5) Alcohol resistance A 50% aqueous solution of ethanol was dropped and wiped out 2 minutes later, and the corrosion and peeling state of the metal thin film layer were visually inspected. (6) Acid resistance The metal thin film layer is immersed in 5% acetic acid aqueous solution for 24 hours.
The peeled state was visually inspected. (7) Alkali resistance The metal thin film layer was immersed in a 1% aqueous sodium carbonate solution for 24 hours, and the state of corrosion and peeling of the metal thin film layer was visually examined. (8) Salt water resistance The metal thin film layer was immersed in a 5% saline solution for 24 hours.
The peeled state was visually inspected. (9) Oil resistance Cottonseed oil was applied and left at 20 ° C. for 24 hours, and the deterioration and peeling state of the metal thin film layer and the protective layer were visually inspected. (10) Plasticizer resistance 100 g of a plastic eraser (dragonfly) is applied and left at 20 ° C. for 24 hours to form a metal thin film layer.
The deterioration and peeling state of the protective layer were visually inspected.

(11) Heat resistance After standing in a dryer at 100 ° C. for 10 minutes, the temperature was returned to room temperature, and then the surface was scratched with a nail, and the state of deterioration of the surface was visually inspected. (12) Abrasion Resistance Abrasion resistance was examined by passing the gate of an automatic ticket gate 2000 times in the same direction. (13) Adhesiveness A cellophane tape peeling test was performed, and the peeling state at the interface between each layer such as the metal thin film layer and the protective layer was visually examined. (14) Washing resistance To 30 cc of hot water of about 35 ° C., add a neutral detergent 4 times.
After putting the card equivalent to 0 mg and washing the card for 15 minutes,
The state of deterioration and peeling of the metal thin film layer, the protective layer, and the like was visually inspected. In the above-mentioned property evaluation, good evaluations were evaluated as ○, good evaluations with slight defects were evaluated as poor, and evaluations with practical problems were evaluated as x.

The evaluation results are as shown in Table 1. The heat-sensitive recording medium of the present invention has no problem with respect to all evaluation items.
It was confirmed that it had excellent durability physically and chemically.

[Table 1]

[0041]

According to the thermal recording medium of the present invention, since the metal thin film layer is firmly adhered to the anchor layer by containing the specific copolymer, the thermal recording medium is resistant to physical stimuli such as abrasion and scratching. And has excellent durability. Further, since the metal thin film layer is provided with a protective layer on the surface thereof and is interposed between the anchor layer and the metal thin film layer, the metal thin film layer is capable of removing chemicals such as acid, alkali and alcohol from both the surface side and the support side. Infiltration can be prevented, and corrosion of the metal thin film layer can be prevented. Accordingly, the present invention has a remarkable effect that excellent physical and chemical durability can be obtained, which can sufficiently withstand severe conditions such as washing, because of its excellent adhesiveness as described above. Since the heat-sensitive recording medium of the present invention has excellent durability as described above, it can be applied to various uses such as providing a magnetic recording layer and using it as a magnetic card.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a layer structure of a thermosensitive recording medium of the present invention.

FIG. 2 is a sectional view showing a layer structure of a thermosensitive recording medium of the present invention.

FIG. 3 is a sectional view showing a layer structure of an embodiment of the thermosensitive recording medium of the present invention.

FIG. 4 is a sectional view showing a layer structure of an embodiment of the thermosensitive recording medium of the present invention.

FIG. 5 is a sectional view showing a layer structure of an embodiment of the thermal recording medium of the present invention.

FIG. 6 is a sectional view showing a layer structure of an embodiment of the thermosensitive recording medium of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 support 2 colored layer 3 anchor layer 4 metal thin film layer 5 protective layer 6 anchor layer containing colorant 7 magnetic recording layer 8 adhesive layer 9 protective layer

 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-60-52390 (JP, A) JP-A-60-18388 (JP, A) JP-A-63-112675 (JP, A) JP-A-53-53 40028 (JP, A) JP-A-1-103493 (JP, A)

Claims (3)

(57) [Claims] To 1. A on a support, a colored layer, an anchor layer, the thermosensitive recording medium comprising successively laminating a metal thin film layer and the protective layer, at least one of the anchor layer is selected maleic acid, phosphorus acid ester And a copolymer having a glass transition temperature of 30 ° C. or higher, and a copolymer containing 20% by weight or more in terms of the total solid content of the anchor layer. A heat-sensitive recording medium characterized in that: 2. An anchor layer containing a colorant on a support,
In the thermosensitive recording medium obtained by successively laminating a metal thin film layer and the protective layer, the anchor layer is maleic acid, at least one and a vinyl chloride and vinyl acetate copolymer component selected from phosphoric acid ester, glass transition A thermosensitive recording medium comprising a copolymer having a temperature of 30 ° C. or higher, and the copolymer containing 20% by weight or more of the total solid content of the anchor layer. 3. The thermosensitive recording medium according to claim 1, wherein said colored layer is a magnetic recording layer.