JP3671467B2 - Information recording medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an information recording medium capable of recording information from color development or discoloration due to absorption or heat generation of near infrared light or infrared light, and more specifically, a thermal recording layer using heat generation by photothermal conversion is provided inside a card. The present invention also relates to an information recording medium that enables visual information to be added to non-contact means such as laser light for individual information after card manufacture.
[0002]
[Prior art]
Currently, as means for recording visible information on information recording media based on vinyl chloride resin, polyethylene terephthalate (PET) resin, paper, etc., inkjet method, thermal transfer method using sublimation transfer ribbon or hot melt transfer ribbon, electrophotographic toner There are various methods such as an electrophotographic method by which arbitrary visible information or images are formed on the surface of the information recording medium. In particular, it is suitable for recording individual information that differs for each information recording medium. Visible information formed by these methods, or the upper surface of the image, several μm to protect them from external factors such as rubbing, rubbing, artificial peeling, penetration of water and chemicals, ultraviolet rays, etc. The overlay (transparent coating layer) is applied. For this overlay, a laminate such as a plastic sheet or a resin coating is used, which can improve the durability of the image.
[0003]
However, when information is newly added after the information recording medium becomes a finished product, the overlay becomes an obstacle to recording. In particular, when information or an image is additionally recorded on the information recording medium at any time or arbitrarily, it is substantially impossible to form an overlay on the recording surface every time information is additionally recorded.
Further, these overlays can be peeled off by a file or the like, and there is a possibility that unauthorized information is rewritten or additionally written on the peeled information recording surface.
[0004]
In addition, the sign panel that carries the signature, which is the means of confirmation for the owner, such as a credit card, cash card, ID card, etc., is also handwritten, but there is a risk of alteration / tampering such as erasing the recording surface or replacing the sign panel. Vulnerable to cheating.
[0005]
In addition, there is a method in which the information recording medium is encapsulated on both sides with a transparent plastic film to completely cover the information recording medium, but the information recording medium is processed in large quantities because an encapsulating process is performed after information recording. In this case, it has the disadvantage that it is not suitable for an information recording medium for use in which additional writing is performed as described above, and in particular, the laminated transparent plastic film is peeled off for modification. There was a risk of tampering and it was vulnerable to fraud.
[0006]
There are other optical recording methods. One of them is an information recording medium such as an optical disk or an optical card. However, since recording is performed in units of pits such as 1 μmφ and 3 μmφ, visual observation is mainly performed. It cannot be used for visual information recording.
Japanese Patent Application Laid-Open No. 55-14695 discloses that an information recording medium is irradiated with laser light while controlling the position and output of the laser light, and the laser light is applied to the core sheet via a transparent cover sheet laminated on the core sheet. Although the recording of information by heat is disclosed, depending on the necessity of high energy laser light and the control of high energy laser light, the cover sheet laminated by the generated heat may be deformed, the position and output There is a problem that it is necessary to precisely control the recording apparatus and the recording apparatus becomes expensive.
[0007]
Furthermore, in order to solve the above problems, a heat-sensitive recording layer and a light-to-heat conversion layer that absorbs energy light such as laser light and generates heat are laminated, and an oversheet is laminated on the outermost layer. There is a method of recording information indirectly by using a medium and absorbing the heat generated by the laser light of the light-to-heat conversion layer and generating heat to use the generated heat as a heat source for the heat-sensitive recording layer. According to this, when information is directly recorded on the thermal recording layer from the outside, the recording can be performed through the oversheet. Therefore, a thermal print recording means such as a thermal head is provided on the thermal recording layer in the information recording medium. If a fraudulent act such as alteration or tampering is used, the scanning trace of the thermal head remains on the oversheet located in the outermost layer, and the fact of the fraudulent act can be clarified, and the thermal recording layer is inside For this reason, it is necessary to increase the heat load applied from the outside in order to perform recording on the heat-sensitive recording layer. If the heat load is large, physical damage such as deformation is caused to the information recording medium. Some have the effect of being able to deter fraud or know the facts easily.
[0008]
[Problems to be solved by the invention]
However, in the above configuration, it is necessary to combine the infrared light absorption layer and the high-sensitivity heat-sensitive recording layer in order to increase the color development efficiency, and it is necessary to select a combination suitable for both layers. In addition, because of the two layers, the conduction of heat generated by absorption of infrared light to the heat-sensitive recording layer is non-uniform, and the color development or discoloration of the heat-sensitive recording layer at the recording portion is not constant, so the printing is unclear or unsatisfactory. Sometimes it was accurate. In addition, heat recording on the heat-sensitive recording layer was possible by heat from the outside.
Therefore, the present invention provides an infrared light absorption heat-sensitive recording layer having the functions of an infrared light absorption layer and a heat-sensitive recording layer, so that the structure is simple, stable against heat from the outside, clear and accurate. An object of the present invention is to provide an information recording medium capable of performing accurate recording.
[0009]
[Means for Solving the Problems]
The present invention, which has been made to achieve the above object,
According to the first aspect of the present invention, Fe is mainly composed of phosphorus pentoxide on at least one surface of the core substrate. ²⁺ And / or Cu ²⁺ An infrared light absorbing thermosensitive recording layer comprising a phosphate-based white crystalline powder containing a transparent coating layer, and the infrared absorbing thermosensitive recording layer is irradiated through the transparent coating layer. An information recording medium for recording visible information by color development or discoloration from heat generated by absorption of external light or infrared light.
[0010]
According to a second aspect of the present invention, in the information recording medium of the first aspect, the infrared light absorbing heat-sensitive recording layer is composed mainly of at least phosphorus pentoxide and Fe. ²⁺ And / or Cu ²⁺ It is formed by applying or printing an infrared absorption heat-sensitive recording material comprising a phosphate-based white crystal powder containing a binder, and an infrared absorption heat-sensitive recording ink material comprising a solvent.
[0011]
According to a third aspect of the present invention, there is provided the information recording medium according to the first aspect, wherein one surface of the ribbon-like base material is mainly composed of phosphorus pentoxide and Fe. ²⁺ And / or Cu ²⁺ An infrared absorption heat-sensitive ink material in which a phosphate-based white crystal powder containing a phosphor is dispersed in a matrix resin and an adhesive layer formed on the other surface of the ribbon-like substrate by coating or printing, respectively. A light-absorbing heat-sensitive recording layer is provided between the core substrate and the transparent coating layer, with the adhesive layer facing the core substrate.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings.
[0013]
FIG. 1 is a plan view of an information recording medium of the present invention, FIG. 2 is a sectional view of the information recording medium taken along line XX of FIG. 1, and FIG. 3 is another embodiment taken along line XX of FIG. 4 is an enlarged cross-sectional view of the infrared light absorbing thermosensitive recording layer of the information recording medium of FIG. 3, and FIG. 5 is an infrared light absorbing thermosensitive recording layer of the information recording medium of the present invention. It is a spectral characteristic curve of the infrared ray absorption heat-sensitive recording layer described in Example 1 used in the above.
[0014]
The information recording medium 1 of the present invention shown in FIG. 1 is provided with an information display section 20 composed of an infrared light absorbing heat-sensitive recording layer 3 on a core substrate 2, and a transparent coating layer 4 is transparent on the upper surface thereof. That is, an oversheet that transmits light in the visible region, near-infrared region, and infrared region and has little absorption is laminated.
In the information display unit 20, unique information and related information of the information recording medium 1 are recorded as an image 21 on the information recording medium 1 by irradiation with laser light in the near infrared region and infrared region from the outside.
The infrared light absorbing thermosensitive recording layer 3 constituting the information display unit 20 is provided between the core base material 2 and the transparent coating layer 4 as shown in FIG. The size of the infrared light-absorbing heat-sensitive recording layer 3 can be arbitrarily determined, and is appropriately determined as necessary.
The infrared light absorbing heat-sensitive recording material used in the present invention contains phosphorus pentoxide as a main component and contains cupric (Cu). ²⁺ ) And / or ferrous iron (Fe) ²⁺ Is formed between the core base material and the transparent coating layer. The information recording medium 1 can be obtained by heat-pressing the core base material and the transparent coating layer at a heat fusion temperature, for example, in the range of 120 ° C. to 150 ° C. for fusing.
[0015]
Specifically, the infrared light absorbing thermosensitive recording material is an infrared absorbing material that does not absorb in the visible region, and the phosphate crystal powder that is the main component thereof contains phosphorus pentoxide as a main component, cupric (Cu). ²⁺ ) And / or ferrous iron (Fe) ²⁺ ) Is contained in an amount of 20% or more, but preferably phosphorus pentoxide is 40 to 70% by weight, cupric (Cu). ²⁺ ) And / or ferrous iron (Fe) ²⁺ ) Is preferably contained in an amount of 30 to 70%. Cu ²⁺ It is more preferable that it is rich. Furthermore, said phosphate type crystal powder can contain the following compounds as needed.
[0016]
Al ₂ O _Three 20.0 to 10.0% by weight
B ₂ O _Three 1.0 to 30.0% by weight
MgO 3.0 to 10.0 wt%
ZnO 0-3.0 wt%
K ₂ O 0 to 15.0 wt%
BaO 0 to 10.0% by weight
SrO 0 to 1.0% by weight
Ni, Co, Se Trace amount
[0017]
The phosphate crystal powder used in the infrared light absorbing thermosensitive recording material, which is the infrared light absorbing thermosensitive recording layer of the information recording medium of the present invention, is a powdered phosphate crystal obtained as described above. In the present invention, the ink is used as a pigment.
[0018]
It is preferable that the amount of such phosphate crystal powder contained in the printing ink composition excluding the solvent is 70% by weight or less. In particular, when the content exceeds 80% by weight, it becomes matt and causes reflection of the phosphate crystal powder surface, that is, reflection of infrared light. Further, the cohesive force becomes a limit, and the adhesiveness and scratching strength are reduced, but the infrared light absorbing thermosensitive recording layer 3 mainly composed of phosphate crystal powder between the core substrate 2 and the transparent coating layer 4. Therefore, the ink may be slightly inferior in mechanical strength as compared with the ink exposed on the surface of the information recording medium.
[0019]
In addition to the infrared light-absorbing heat-sensitive recording material of the infrared light-absorbing heat-sensitive recording layer of the present invention, that is, the binder which is another substance contained in the infrared light-absorbing heat-sensitive recording printing ink, an infrared light-absorbing heat-sensitive recording material is used. As long as it is not altered or affected, it may be one that is usually used in inks. For example, vinyl acetate resin, vinyl chloride-vinyl acetate copolymer resin, polyurethane resin, ethylene vinyl acetate resin, polyamide resin, polyester Various resins such as a resin, an atactic tech polypropylene resin, and a polyurethane elastomer can be used, and these can obtain a necessary adhesive strength with the transparent plastic sheet of the transparent coating layer 4 in the heat fusion (heat lamination) process. .
[0020]
The binder is preferably contained in an infrared light-absorbing thermal recording printing ink composition excluding the solvent in an amount of 20% by weight or less. In addition, the infrared-absorbing heat-sensitive recording printing ink of the present invention may contain various additives such as an antifoaming agent and a lubricant in addition to the infrared light-absorbing heat-sensitive recording material and the binder.
[0021]
Further, as a solvent used in infrared absorbing heat-sensitive recording printing ink, toluene, methyl isobutyl ketone, xylene, cyclohexanol, isobutyl acetate, cyclohexanone, methylcyclohexanone, glycol derivatives such as ethylene glycol monobutyl ether, etc., or a mixed solvent thereof Is mentioned.
[0022]
The infrared light-absorbing heat-sensitive recording printing ink is formed by various known forming methods such as screen printing, offset printing, gravure printing, and other known forming methods such as gravure coating, roll coating, and bar coating. Or after printing or apply | coating to the required part of the transparent coating layer 4, the infrared-light absorption thermosensitive recording layer 3 is formed by drying.
[0023]
Next, the core substrate 2 is not particularly limited as long as it is a material normally used for an information recording medium such as a card. For example, vinyl chloride, polythiethylene terephthalate (PET), acrylonitrile-butadiene-styrene. Examples thereof include thermoplastic resins such as copolymers (ABS), polystyrene and polycarbonate, thermosetting resins, so-called biodegradable resins such as microorganism-produced polyester and polylactic acid. The thickness of the core substrate 2 varies depending on the application, but is generally 300 to 800 μm for a card application.
[0024]
Further, the transparent coating layer 4 needs to be an oversheet having sufficient transparency, that is, a light-absorbing oversheet that transmits light in the visible region, near infrared region, and infrared region, and has a certain degree of rigidity. The surface is not particularly limited as long as it has surface smoothness. Examples thereof include polymer films such as polyester film, polyolefin film, vinyl chloride film, and polylactic acid film. Although the thickness of the transparent coating layer 4 varies depending on the application, it is 50 to 150 μm in the case of a general card application in consideration of the relationship with the core substrate 2.
Moreover, the transparent coating layer 4 can also color an oversheet with a coloring agent in the range which has no influence.
[0025]
Further, on the surface of the core substrate 2 other than the infrared light absorbing thermosensitive recording layer 3, a printing layer (not shown) such as a pattern or a character may be provided as long as it does not become an obstacle, and may be provided on one side or both sides. it can. The transparent coating layer 4 may be provided only on the surface of the core substrate 2 where the infrared light absorption thermosensitive recording layer is formed, or may be laminated on the surface where the infrared light absorption thermosensitive recording layer 3 is not formed. When the infrared light absorption heat-sensitive recording layer 3 is not formed, it may not be transparent, and a printing layer (not shown) such as a pattern or characters may be provided on the upper surface. Furthermore, a protective layer (not shown) can be provided as necessary to protect this.
[0026]
After the core substrate 2, the infrared light absorbing heat-sensitive recording layer 3 and the transparent coating layer 4 are laminated, heating and pressing (for example, 80 to 160 ° C., 30 to 150 Kg / cm) in a heat fusion (thermal lamination) step. ² 1 to 5 minutes) and integrated by thermal fusion of the layers to form an information recording medium. The thickness at this time is not particularly limited, but is 500 to 1000 μm for general card applications.
[0027]
Next, an information recording medium 11 according to another embodiment of the present invention shown in FIG. 2 has a ribbon-like substrate 12, that is, a plastic substrate, between the core substrate 2 and the transparent coating layer 4, as shown in FIG. An infrared absorption thermal recording layer 13a is formed by coating or printing infrared absorption thermal recording printing ink on a coating method, and forming an infrared absorption thermal recording layer 13a by drying, and then processing into a ribbon (small piece). The core base material 2 and the plastic base material 12 can be bonded using the adhesive layer 14. As a result, there is an effect that a positional shift of the infrared light absorption heat-sensitive recording layer 13 is not caused during a heat fusion (thermal lamination) step. If the infrared light absorbing thermosensitive recording layer 13 is not sufficiently bonded to the core base material and the transparent coating layer, the mechanical strength of the information recording medium itself is insufficient.
In addition, since the core base material 2 and the transparent coating layer 4 are the same as that of FIG. 1, the effect is also the same, description is abbreviate | omitted here.
[0028]
The ribbon-shaped substrate 12, that is, a plastic substrate, may be a material used for a card, a film, a sheet, or the like, and is not particularly limited, and examples thereof include polythiethylene terephthalate (PET) and a polyolefin film. The thickness of the ribbon-shaped substrate 12 is generally 20 to 50 μm, although it varies depending on the application.
After the infrared absorption heat-sensitive recording printing ink of the infrared light absorption heat-sensitive recording layer 3 in FIG. 1 is printed or applied by the same various known forming methods, the infrared light absorption heat-sensitive recording layer 13 is formed by drying. .
[0029]
Examples of the adhesive layer 14 include ethylene vinyl acetate, polyamide, polyester, and atactic polypropylene, and a heat-sensitive adhesive material is preferable. If necessary, rosin resins, petroleum resins, waxes, antioxidants, inorganic fillers, plasticizers and the like can be added as tackifiers. The adhesive layer 14 can also be formed by various known forming methods.
[0030]
The principle of recording information on the infrared light absorbing thermosensitive recording layers 3 and 13 which are the information display unit 20 of the information recording medium of the present invention is that the main component, the infrared absorbing thermosensitive recording material, is based on the absorption of laser light. It has been found that the color changes to black. The details of the principle of discoloration of this phosphate crystal powder from white to black are unclear, but as the temperature rises (heat generation) due to absorption of laser light, it reacts black and the reaction is irreversible. confirmed. According to the spectral characteristic curve shown in FIG. 5, this infrared-absorbing thermosensitive recording material (consisting of the composition described in Example 1 below) has no absorption in the visible region, and has an absorption up to 700 nm to 1200 nm or more. It has absorption in the near infrared region in the range of 700 nm to 1100 nm, and in particular, an infrared absorption thermal recording layer by irradiation with laser light such as a semiconductor laser or YAG laser having a wavelength of 800 to 1100 nm and an energy density or output of 200 mW to 50 W. The temperature can be raised to the temperature necessary to change the color of the material to black. This enables printing and records information. If it is less than that, it will absorb infrared light as shown in FIG. The infrared-absorbing heat-sensitive recording material is cupric (Cu ²⁺ ) And ferrous iron (Fe) ²⁺ ), The light absorption is less likely to appear in the visible region due to the crystal structure.
[0031]
In addition, this infrared absorptive thermosensitive recording material is a white and highly sensitive thermosensitive recording material that absorbs infrared light, and is a material that does not develop color at the heat fusion temperature between the core substrate and the transparent coating layer, Since a heat laminating process, which is a method for manufacturing an information recording medium such as a normal card, can be used, it is not necessary to change the current card manufacturing process.
[0032]
Furthermore, even if the information recording medium is irradiated with laser light of a predetermined wavelength and output and recorded on the infrared light absorbing thermosensitive recording layer, the infrared light absorbing thermosensitive recording layer is heated, and the core substrate and the transparent coating layer are heated. Heat is transmitted but does not rise to the deformation temperature, so that each layer of the information recording medium is not deformed due to overheating, and the infrared light absorption heat-sensitive recording layer inside the information recording medium has a size that can be visually observed individually. Information can be additionally recorded arbitrarily.
Since the infrared light absorbing heat-sensitive recording layer of the information recording medium of the present invention has high sensitivity, the recording apparatus can be recorded with a simple and low energy output laser.
[0033]
Note that the infrared light absorption heat-sensitive recording layer of the information recording medium of the present invention can be recorded with a laser having a low energy output, but the temperature rises over a long time in order to efficiently absorb the irradiated laser light. In this case, the oversheet of the transparent coating layer may be deformed by heat conduction, so it is necessary to raise the temperature with the minimum necessary energy within a short time. As described above, the information recording of the present invention This is possible in the infrared light absorbing thermosensitive recording layer of the medium.
Furthermore, since the recording of the infrared light absorption heat-sensitive recording layer is judged visually, the non-recorded portion is a material that does not absorb in the visible region.
[0034]
According to the infrared light absorption heat-sensitive recording layer of the information recording medium of the present invention, since the layer structure is simple, the production is easy and the laminate process is very stable against heat from the outside. Therefore, the heat-sensitive recording layer is not deteriorated, and the card has the durability.
[0035]
【Example】
The present invention will be described in detail with reference to specific examples.
(Example 1)
An infrared absorption thermal recording printing ink having the following composition was prepared.
○ Infrared absorption thermal recording printing ink
30 parts of pigment (phosphate-containing copper-containing white crystalline compound)
10 parts of vinyl acetoacetate resin (S-Surek Chemical Co., Ltd. S-Rec A)
Saturated polyester (Toyobo Byron 103) 5 parts
12 parts of polyurethane elastomer (N-2304 made by Nippon Polyurethane)
Isocyanate curing agent 3 parts
0.5 parts of triethylenediamine
60 parts of solvent (toluene / MEK)
However, the phosphate-based copper-containing white crystalline compound has the following composition (% by weight).
○ Phosphate-based copper-containing white crystalline compound
P ₂ O _Five 49.75
CuO 49.75
ZnO 0.5
[0036]
A printing ink obtained on a core sheet made of a vinyl chloride resin having a thickness of 540 μm serving as the core substrate 2 was applied in a pattern to a thickness of 8 μm to form an infrared absorption thermosensitive recording layer 3, and after drying, A sheet made of a transparent vinyl chloride resin to become a 100 μm transparent coating layer 4 is laminated on both surfaces of the core substrate 2, and 140 ° C./Kg/100 cm. ² -Each layer was heat-sealed by heating and pressurizing under conditions of 3 minutes, and punched into a card shape to produce an information recording medium 1.
In addition, the sheet | seat which consists of transparent vinyl chloride resin which is the transparent coating layer 4 was given to printing as needed.
[0037]
A YAG laser having a wavelength of 1067 nm, a beam diameter of 100 μm, and an output of 6 W was used for the produced information recording medium 1, and images such as letters, numbers, and patterns were recorded at a scanning speed of 40 mm / sec. The irradiated laser beam heats up the infrared absorption thermal recording layer 3 made of a white infrared absorption thermal recording material without thermally affecting the transparent vinyl chloride resin sheet which is the transparent coating layer 4. The color changed to black, whereby a black image 21 was obtained on a white background. At this time, the line width of the image 21 is about 140 μm and is a sufficiently visible image. Each layer had sufficient mechanical strength, and no delamination was caused even by external deformation.
[0038]
(Example 2)
An infrared absorption thermal recording printing ink having the following composition was prepared.
○ Infrared absorption thermal recording printing ink
30 parts of pigment (phosphate-containing copper-containing white crystalline compound)
10 parts of vinyl acetoacetate resin (S-Surek Chemical Co., Ltd. S-Rec A)
60 parts of solvent (toluene / MEK)
However, the phosphate-based copper-containing white crystalline compound has the following composition (% by weight).
○ Phosphate-based copper-containing white crystalline compound
P ₂ O _Five 50.0
CuO 40.0
Al ₂ O _Three 5.0
K ₂ CO _Three 5.0
[0039]
The printing ink obtained on a 25 μm-thick polyester sheet as the plastic substrate 12 was applied to a thickness of 8 μm, dried, and then polyamide-coated as an adhesive layer 14 on the back surface. This polyester sheet was slit to a width of 10 mm to form a ribbon.
Next, the white infrared-absorbing thermosensitive recording layer 13 processed into a ribbon shape is temporarily bonded to the surface of a core sheet made of a vinyl chloride resin having a thickness of 540 μm, which becomes the core substrate 2, and then a transparent coating layer having a thickness of 100 μm. Laminate sheets made of transparent vinyl chloride resin to be 4 and 140 ° C / Kg / 200cm ² -Each layer was heat-sealed by heating and pressurizing under conditions of 3 minutes, and punched into a card shape to produce an information recording medium 11.
In addition, the sheet | seat which consists of transparent vinyl chloride resin which is the transparent coating layer 4 was given to printing as needed.
[0040]
A semiconductor laser having a wavelength of 830 nm, a beam diameter of 50 μm, and an output of 3 W was used for the produced information recording medium 12, and image recording such as letters, numbers, and patterns was performed at a scanning speed of 20 mm / sec. Irradiated laser light does not affect the sheet made of transparent vinyl chloride resin, which is the transparent coating layer 4, and does not thermally affect the infrared absorbing thermosensitive recording layer 3 made of white infrared absorbing thermosensitive recording material. Heats up and turns black, thereby obtaining a black image 21 on a white background. The line width of the image 21 at this time is about 80 μm, and is a sufficiently visible image. Each layer had sufficient mechanical strength, and no delamination was caused even by external deformation.
[0041]
(Example 3)
An infrared absorption thermal recording printing ink having the following composition was prepared.
○ Infrared absorption thermal recording printing ink
Pigment (phosphate-containing iron-containing white crystalline compound) 35 parts
8 parts of vinyl acetoacetate resin
Saturated polyester (Toyobo Byron 103) 5 parts
10 parts of polyurethane elastomer (N-2304 made by Nippon Polyurethane)
Isocyanate curing agent 3 parts
0.5 parts of triethylenediamine
60 parts of solvent (toluene / MEK)
However, the phosphate-based iron-containing white crystalline compound has the following composition (% by weight).
○ Phosphate iron-containing white crystalline compound
P ₂ O _Five 55.0
FeO 40.0
Al ₂ O _Three 5.0
[0042]
A printing ink obtained on a core sheet made of a vinyl chloride resin having a thickness of 540 μm serving as the core substrate 2 was applied in a pattern to a thickness of 8 μm to form an infrared absorption thermosensitive recording layer 3, and after drying, A sheet made of a transparent vinyl chloride resin to become a 100 μm transparent coating layer 4 is laminated on both surfaces of the core substrate 2, and 140 ° C./Kg/200 cm. ² -Each layer was heat-sealed by heating and pressurizing under conditions of 3 minutes, and punched into a card shape to produce an information recording medium 1.
In addition, the sheet | seat which consists of transparent vinyl chloride resin which is the transparent coating layer 4 was given to printing as needed.
[0043]
A YAG laser having a wavelength of 1067 nm, a beam diameter of 100 μm, and an output of 6 W was used for the produced information recording medium 1, and images such as letters, numbers, and patterns were recorded at a scanning speed of 40 mm / sec. The irradiated laser light does not affect the sheet made of the transparent vinyl chloride resin, which is the transparent coating layer 4, and does not thermally affect the infrared absorbing thermosensitive recording layer 3 made of a white infrared absorbing thermosensitive recording material. Heats up and turns black, which gives a black image 21 on a white background. The line width of the image 21 at this time is about 80 μm, and is a sufficiently visible image. Each layer had sufficient mechanical strength, and no delamination was caused even by external deformation.
[0044]
(Example 4) ²⁺ And Cu ²⁺ It would be better to give an example of a phosphate-based white crystal powder containing both. Or you may illustrate some examples of composition of a white crystal compound containing phosphoric acid copper iron.
[0045]
【The invention's effect】
According to the first aspect of the present invention, any visible information can be recorded for each information recording medium, and the information is recorded inside the information recording medium. Therefore, an operation such as peeling off a transparent coating layer laminated on the surface, for example, a 100 μm transparent plastic sheet, is necessary, and the trace of the action remains, so that the fact of fraud becomes clear.
Furthermore, since the infrared light absorption heat-sensitive recording layer is white and has excellent infrared absorption capability, it is possible to make the structure of the information recording medium simple because one layer can absorb and generate infrared light and color. .
[0046]
Infrared-light-absorbing heat-sensitive recording layer placed between the core sheet and oversheet by heat-fusion method is like conventional heat-sensitive recording materials such as leuco, diazo, and low molecular / high molecular materials. In addition, there was no thermal change and no deterioration in recording performance was observed after heat sealing. In addition, the infrared light absorption heat-sensitive recording layer has no absorption in the visible region and has absorption in the near infrared region from 700 nm to near 1100 nm, so that a laser such as a semiconductor laser or a YAG laser can be used and irradiated. Since the laser beam can be absorbed efficiently, it can be recorded with a laser having a low energy output, so that it is possible to record without giving thermal deformation to the transparent plastic sheet on the surface of the information recording medium by the irradiation of the laser beam. .
[0047]
According to the second aspect of the present invention, the infrared absorption heat-sensitive recording layer can be formed only in a necessary portion by a printing method or a coating method, and the design of the information recording medium is not hindered. A manufacturing process can be used.
The binder used in the infrared absorption heat-sensitive recording printing ink can sufficiently bond the infrared absorption heat-sensitive recording layer to the core substrate and the transparent coating layer in the fusing step by heating and pressing.
[0048]
According to the invention described in claim 3, after the infrared absorption thermosensitive recording layer is coated on a plastic substrate and processed into a ribbon shape, it can be disposed only in a desired portion of the core substrate, The design of the information recording medium is not hindered and the manufacturing process is simple.
In addition, the infrared absorbing thermosensitive recording layer is used as a core substrate in the fusing process by heating and pressurizing by the binder used in the infrared absorbing thermosensitive recording printing ink and the adhesive layer on the back of the plastic substrate of the infrared absorbing thermosensitive recording layer. And can be sufficiently adhered to the transparent coating layer.
[0049]
Since the infrared absorption heat-sensitive recording layer of the information recording medium of the present invention is highly sensitive and can be recorded with a laser beam having a low energy output, the recording apparatus can be simplified.
[0050]
[Brief description of the drawings]
FIG. 1 is a plan view of an information recording medium of the present invention.
FIG. 2 is a cross-sectional view of the information recording medium taken along line XX in FIG.
FIG. 3 is a cross-sectional view of an information recording medium of another embodiment taken along line XX of FIG.
4 is an enlarged cross-sectional view of an infrared light absorbing thermosensitive recording layer of the information recording medium of FIG.
FIG. 5 shows the infrared light absorbing thermosensitive recording layer described in Example 1 (recording layer formed by printing infrared absorbing thermosensitive recording ink) used for the infrared light absorbing thermosensitive recording layer of the information recording medium of the present invention. It is a spectral characteristic curve.
[Explanation of symbols]
1,11 Information recording medium
2 Core substrate
3 Infrared absorption thermal recording layer
4 Transparent coating layer
12 Ribbon substrate
13 Infrared absorption thermal recording layer
13a Infrared light absorbing thermosensitive recording layer
14 Adhesive layer
20 Information display section
21 images

Claims (3)

An infrared-absorbing heat-sensitive recording layer comprising a phosphate-based white crystalline powder containing Fe ²⁺ and / or Cu ²⁺ containing phosphorus ^pentoxide as a main component on at least one surface of a core substrate; and a transparent coating layer The infrared absorption thermosensitive recording layer is laminated and records visible information by color development or discoloration from heat generation due to absorption of near infrared light or infrared light irradiated through the transparent coating layer. To record information. The infrared light absorbing thermosensitive recording layer comprises an infrared absorbing thermosensitive recording material comprising at least phosphorus pentoxide as a main component and a phosphate-based white crystal powder containing Fe ²⁺ and / or Cu ²⁺ , a binder, and a solvent. 2. The information recording medium according to claim 1, wherein the information recording medium is formed by application or printing of an infrared absorption thermal recording ink material. An infrared-absorbing thermal ink material in which a phosphate-based white crystal powder containing phosphorous ^pentoxide as a main component and containing Fe ²⁺ and / or Cu ²⁺ is dispersed in a matrix resin on one surface of a ribbon-like substrate; An infrared ray absorption thermosensitive recording layer formed by applying or printing an adhesive layer on the other surface of the ribbon-shaped substrate is disposed between the core substrate and the transparent coating layer. The information recording medium according to claim 1, wherein the information recording medium is provided.

Images