JP2014203301A - Reversible thermosensitive recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-contact IC recording medium that prevents curl of a rewrite sheet, and improves printing durability, visibility of a pattern printing layer and concealability of an IC chip.SOLUTION: A non-contact IC recording medium includes a protective layer, a reversible thermosensitive recording layer, a front base material, a core sheet and a back base material that are laminated with each other, and has a thickness of 680-840 μm. The front base material has haze value of 4.5% or less and a thickness of 75-125 μm. On the front base material side of the core sheet, or the core sheet side of the front base material, a printing layer is formed.

Description

  The present invention relates to a contactless integrated circuit (IC) recording medium and the like.

  In various cards such as an identification card (ID) card and a prepaid card, for example, visual recording is required in addition to magnetic recording. As visual recording, thermal recording is widely performed because it is inexpensive and has good color development.

  Generally, a heat-sensitive recording material is formed by dispersing a pigment such as a leuco dye and a developer in a binder and coating the surface of a substrate.

  When the heat-sensitive recording material is heated with a device such as a thermal head, the binder dissolves and the dye and the developer react to develop color. However, since the heat-sensitive recording material usually cannot be restored once the color is developed, reversible recording cannot be performed.

  Therefore, in order to perform reversible thermosensitive recording in response to a request to rewrite the recording, a coloring / decoloring type reversible thermosensitive recording material has been proposed. A coloring / decoloring type reversible thermosensitive recording material reversibly repeats a coloring state and a decoloring state.

  As the color development / decoloration type reversible thermosensitive recording material, for example, Patent Documents 1 to 3 describe an electron donating dye precursor and a developer / subtracting agent that develops or decolors the electron donating dye precursor by heating. ing. Patent Documents 1 to 3 propose control of recording and erasing by heat.

  As a specific example of a color developing / decoloring type reversible thermosensitive recording material, as shown in FIG. 1, recording necessary for rewritable printing on transparent polyethylene terephthalate (PET) which is a surface base material (4). A method is known in which a sheet on which a layer (3) is formed is attached to a core sheet (6) on which a printed layer (5) having a pattern is formed. Further, the printed layer (5) can be visually recognized through a transparent rewritable sheet formed of the protective layer (1), the intermediate layer (2), the recording layer (3) and the front substrate (4).

  Patent Document 4 describes that the thickness of the transparent base film is controlled in the range of 8.5 μm to 300 μm, preferably in the range of 8.5 μm to 250 μm.

  Patent Document 5 describes that the thickness of the transparent substrate film is only required to be able to withstand processing such as coating, and is, for example, 5 μm to 200 μm.

  Patent Document 6 describes a reversible thermosensitive recording medium using transparent polyvinyl chloride (PVC) having a thickness of 100 μm as a base material.

JP-A-2-188293 JP-A-2-188294 International Publication No. 90/11898 JP 2001-341427 A Japanese Patent No. 3716084 JP 2001-287457 A

Generally, for a recording medium capable of performing both non-contact communication recording and reversible visible recording, the thickness of the transparent PET film used for the front substrate is 50 μm in order to ensure the visibility of the printed layer. It is as follows.
Further, a protective layer having high heat resistance is formed on the rewrite layer in order to repeatedly perform printing using a thermal head. A protective layer having high heat resistance is generally formed by irradiating with ultraviolet rays (UV) at a high output and a high crosslinking density.

  However, when the protective layer shrinks, the transparent PET film on which the protective layer is laminated curls, so that there may be a case where a rewritable sheet cannot be produced.

  Further, if the UV irradiation output is lowered to lower the crosslinking density of the protective layer in order to prevent curling of the transparent PET film having a thickness of 50 μm or less, the printing durability of the rewritable sheet is lowered.

Furthermore, when producing a non-contact IC card, generally, as a core sheet, a PET copolymer (PET-G) or PVC having a heat resistance lower than that of PET is used in order to ensure the adhesion between each base material or sheets. Since it is used, in order to increase the heat resistance of the non-contact IC card, the surface substrate (that is, the transparent PET film) must be thickened.
However, when the surface base material becomes thick, the visibility of the printed layer decreases.

  In this connection, Patent Documents 4 to 6 describe the thickness of the transparent film or the transmittance of the film, but do not mention the thickness of the core sheet or the concealability of the IC chip. That is, if the transparent film described in Patent Documents 4 to 6 is made thick and the transmittance is lowered, the core sheet must be made thin in order to keep the thickness of the non-contact IC card constant. It will be difficult to conceal.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a non-contact type IC recording medium that prevents curling of a rewrite sheet and improves printing durability, printed layer visibility, and IC chip concealment.

  The present inventors have found that in the non-contact IC recording medium having a specific thickness, the above problem can be solved by balancing the haze value and thickness of the transparent PET used for the front substrate, The present invention has been completed.

That is, the present invention is as follows:
[1] A non-contact IC recording medium comprising a laminated protective layer, a reversible thermosensitive recording layer, a front substrate, a core sheet and a back substrate and having a thickness of 680 μm to 840 μm,
The front substrate has a haze value of 4.5% or less and a thickness of 75 μm to 125 μm, and a printed layer is formed on the front substrate side of the core sheet,
Non-contact IC recording medium.

[2] A non-contact IC recording medium comprising a laminated protective layer, a reversible thermosensitive recording layer, a front substrate, a core sheet and a back substrate, and having a thickness of 680 μm to 840 μm,
The front substrate has a haze value of 4.5% or less and a thickness of 75 μm to 125 μm, and a printed layer is formed on the core sheet side of the front substrate,
Non-contact IC recording medium.

  [3] The non-contact IC recording medium according to [1] or [2], wherein the front substrate and the back substrate are formed of the same resin and have the same thickness.

  According to the present invention, since the thickness of the core sheet can be ensured, the concealing property of the non-contact IC chip can be improved.

  Moreover, according to this invention, since a transparent rewrite sheet can be formed, the pattern of a printing layer can be kept clear and the visibility of a printing layer can be improved.

  Furthermore, according to the present invention, since the crosslink density of the protective layer and the thickness of the surface base material can be balanced, the curling of the rewrite sheet can be prevented and the protective layer can be strengthened to improve the printing durability of the rewrite sheet. And solvent resistance can be improved.

FIG. 1 is a schematic diagram showing a layer structure of a non-contact IC recording medium. FIG. 2 is a schematic diagram showing a layer structure of a card manufactured in the example.

  Hereinafter, embodiments of the present invention will be described in detail.

  The present invention is not limited to the following embodiments, and can be implemented with various modifications within the scope of the gist of the present invention.

[Non-contact integrated circuit (IC) recording medium]
The non-contact IC recording medium is a recording medium including a non-contact type IC.

A non-contact IC refers to an integrated circuit that can perform communication without contacting a reader / writer unit of a terminal.
The recording medium is a medium capable of recording information, and may be in the form of a card, a sheet, a disk, or the like.

  Generally, since there is a portion functioning as an antenna in a non-contact IC recording medium, when the non-contact IC recording medium is exposed to a magnetic field or electric field generated from a reader / writer unit of the terminal, the terminal is Information can be transmitted and received between the contactless IC recording medium and the contactless IC recording medium.

  The non-contact IC recording medium is formed from a laminate including a protective layer, a reversible thermosensitive recording layer, a front substrate, a printed layer, a core sheet, and a back substrate.

The laminate preferably includes a protective layer, a reversible thermosensitive recording layer, a front substrate, a printed layer, a core sheet, and a back substrate in order from the front side to the back side of the laminate.
Further, as shown in FIG. 1, an intermediate layer (2) may be disposed between the protective layer (1) and the reversible thermosensitive recording layer (3).

  In order to use a non-contact IC recording medium as a rewrite sheet that is generally distributed, the thickness of the non-contact IC recording medium is preferably 680 μm to 840 μm.

  Further, the portion including the protective layer, if desired, the intermediate layer, the reversible thermosensitive recording layer, and the surface base material is called a rewrite sheet because the reversible thermosensitive recording layer can reversibly achieve thermal recording. Therefore, the rewrite sheet imparts rewrite properties to the non-contact IC recording medium.

[Components of non-contact IC recording medium]
Hereinafter, “substrate”, “reversible thermosensitive recording layer”, “intermediate layer”, “protective layer”, “core sheet”, and “printing layer”, which are components of the non-contact IC recording medium, will be described.

[Base material]
The non-contact IC recording medium includes at least three types of base materials.
The first substrate is a surface substrate on which a reversible thermosensitive recording layer is laminated,
And the second substrate is a core substrate on which a core sheet is formed,
And a 3rd base material is a back base material with which a core sheet is laminated | stacked.
Below, a front base material and a back base material are each demonstrated.

[Front substrate]
The front substrate has a haze value of 4.5% or less and a thickness of 75 μm to 125 μm in order to balance the curling of the rewrite sheet, the visibility of the printed layer, and the concealment of the IC chip. .

  The form of the front substrate can be determined according to the form of the non-contact IC recording medium, but is preferably a film.

  The surface base material can be formed of a synthetic resin such as polyethylene terephthalate (PET), polyvinyl chloride (PVC), polystyrene (PS), polycarbonate (PC), ABS resin, epoxy resin, polyamide resin.

  However, a haze value of 4.5% or less, or a property that does not dissolve the substrate when the resin is applied on the substrate and dried, and a property that does not generate burrs at the edge when the substrate is punched into a card mold In consideration of card processability such as, the surface base material is preferably formed of transparent PET.

[Back substrate]
The backing substrate can be formed of PET.
The back substrate may be transparent, translucent, opaque or white, but in order to prevent the card from twisting when the substrate is made into a card, it is preferable that the orientation direction and thickness are aligned with the front substrate. As described above, since the front substrate is generally formed of transparent PET, it is more preferable that the back substrate is also formed of transparent PET.
The core sheet will be described later.

[Reversible thermosensitive recording layer]
The reversible thermosensitive recording layer is a layer that contains a reversible thermosensitive composition that can form a relatively colored state due to the difference in heating temperature and cooling rate after heating, and that repeats color development / decoloration reversibly by heat. .

The reversible thermosensitive composition includes a leuco dye, a color reducing agent, and optionally other additives. Therefore, the reversible thermosensitive recording layer can be formed by mixing and molding the reversible thermosensitive composition and the binder resin.
Hereinafter, the binder resin, the leuco dye, the visible color reducing agent, and other additives will be described.

[Binder resin]
As the binder resin, in addition to the thermosetting acrylic resin, polyurethane, polyester resin, ultraviolet curable resin and the like can be used.

[Leuco dye]
As the leuco dye, known materials used for the reversible thermosensitive composition can be used.

  Examples of leuco dyes include crystal violet lactone, 3-indolino-3-p-dimethylaminophenyl-6-dimethylaminophthalide, 3-diethylamino-7-chlorofluorane, 2- (2-chlorophenylamine)- Diethylaminofluorane, 2- (2-fluorophenylamino) -6-diethylaminofluor) lane, 2- (2-fluorophenylamino) -6-di-n-butylaminofluorane, 3-diethylamino-7-cyclohexylamino Fluorane, 3-diethylamino-5-methyl-7-t-butylfluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-p-butylanilinofluor Oran, 3-cyclohexylamino-6-chlorofluorane, 2- Nilino-3-methyl-6- (N-ethyl-p-toluidino) -fluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 3-pyrrolidino-7-cyclohexylaminofluorane, 3-N- Examples include methylcyclohexylamino-6-methyl-7-anilinofluorane and 3-N-ethylpentylamino-6-methyl-7-anilinofluorane.

[Developing color reducing agent]
As the color-developing agent, a known material used for the reversible thermosensitive composition can be used.

  Examples of the color reducing agent include (N- (p-hydroxyphenyl) -N′-n-octadecylthiourea, N- (p-hydroxyphenyl) -N′-n-octadecylurea, N- (p-hydroxy). Phenyl) -N′-n-octadecylthioamide, 4′-octadecananilide, 2-octadecylterephthalic acid, N-octadecyl (p-hydroxyphenyl) amide, N- (p-hydroxybenzoyl) -N-octadecanoylamine, N- [3- (p-hydroxyphenyl) propiono] -N′-octadecanohydrate, N-[(p-hydroxyphenyl) methyl] -n-octadecylamide, N-[(p-hydroxyphenyl) methyl ] -N-octadecyl urea, N-[(p-hydroxyphenyl) methyl] -N'-n-octadecyloxy Bromide), and the like.

[Other additives]
The reversible thermosensitive composition can contain additives such as a curing agent and an ultraviolet absorber, if desired.

  Examples of the curing agent include hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI), and the like.

  Examples of the ultraviolet absorber include benzophenone compounds, hydroxyphenyltriazine compounds, oxalic acid anilide compounds, and the like.

[Intermediate layer (anchor layer)]
The intermediate layer is a layer located between the protective layer and the reversible thermosensitive recording layer, or between the reversible thermosensitive recording layer and the front substrate. In this specification, the intermediate layer is also called an anchor layer.
In order to improve the adhesion between the protective layer and the reversible thermosensitive recording layer, or the adhesion between the front substrate and the reversible thermosensitive recording layer, it is preferable to form an anchor layer.

The anchor layer is preferably formed of a resin.
For example, the resin for forming the anchor layer includes a polymer in which a compound having an isocyanate group and a compound having a hydroxyl group are condensed via a urethane bond.

A compound having an isocyanate group is a compound having two or more isocyanate groups in the molecule and capable of reacting with a hydroxyl group to form a urethane bond.
Examples of the compound having an isocyanate group include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and the like.

A compound having a hydroxyl group is a compound having two or more hydroxyl groups in the molecule and capable of reacting with an isocyanate group to form a urethane bond.
Examples of the compound having a hydroxyl group include polyether polyol, polyester polyol, polycarbonate polyol, and polycaprone lactone polyol.

The anchor layer can also contain a UV absorber if desired. Therefore, the ultraviolet absorber can be contained in the resin for forming the anchor layer.
As an ultraviolet absorber, what was described as a content of the said reversible thermosensitive composition can be used.

[Protective layer]
The protective layer is a layer for protecting the reversible thermosensitive recording layer disposed on the front side of the non-contact IC recording medium.
By disposing the protective layer on the front side of the reversible thermosensitive recording layer, the heat resistance and printing durability of the non-contact IC recording medium can be improved.

The protective layer is more preferably formed of an ultraviolet curable resin.
Examples of the ultraviolet curable resin include urethane acrylate resin, polyester acrylate resin, and epoxy acrylate resin.

  The protective layer may contain additives such as a lubricant such as silica, silicone oil and wax, a waterproofing agent such as glyoxal, a dispersant, an antifoaming agent, an antioxidant and a fluorescent dye.

[Core sheet]
The core sheet is a component that is located between the front substrate and the back substrate and includes an inlet portion.
As shown in FIG. 1, the core sheet (6) can be formed by laminating the core base material (7) on the front and back of the inlet portion including the IC chip (8).

  Below, an inlet part, the film substrate contained in an inlet part, the IC chip contained in an inlet part, and a core base material are each demonstrated.

[Inlet part]
An inlet part means the part located in a core sheet.
The inlet portion includes a film substrate, and a component for achieving contactless communication recording is mounted on the film substrate.

  Examples of components for achieving non-contact communication recording include an IC chip and an antenna pattern.

[Film substrate]
The film substrate is used to hold components for achieving contactless communication recording thereon.
The film substrate can be formed of a resin film. Examples of the resin film include a PET film, a polyethylene naphthalate film, and a PET-G film. In addition, PET-G is a copolyester obtained by copolymerizing by adding a second glycol in the polymerization process of ethylene glycol and terephthalic acid.

  In general, an antenna pattern is formed on the film substrate along the periphery thereof. The antenna pattern is, for example, a method in which aluminum foil or copper foil is attached to a film substrate and a loop shape is formed by etching, a method in which a silver paste is printed by screen printing to form a loop shape, a wire is drawn to form a loop shape And a method of transferring the antenna pattern transfer foil to form a loop, and the like.

[IC chip]
An IC chip is a chip component on which a semiconductor integrated circuit such as a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), or an EP ROM is mounted. And the inlet part.
The IC chip is connected to the antenna pattern while being mounted on the surface of the film substrate.

[Core substrate]
The core substrate is a material for forming a core sheet together with the inlet portion, and is also referred to as a core material in the present specification.
The core material is preferably a resin having low heat resistance in order to satisfactorily fill the core base material with the IC chip mounted on the inlet portion. Examples of the resin having low heat resistance include PET-G and PVC.

[Method for producing core sheet]
The core sheet can be formed, for example, by laminating a core base material on the front and back of the inlet part, surrounding the inlet part with a core material, or embedding the inlet part in the core material.

[Print layer]
The print layer is a layer formed by printing.
The printed layer has an arbitrary pattern for transmitting visually observable information. Examples of patterns include patterns, characters, symbols, figures, characters, background colors, and shades.

  The printing layer can be formed by a known printing method using a known material. Further, the printing layer can be formed on the front base material side of the core sheet or on the core sheet side of the front base material. More specifically, the pattern can be printed on the core sheet side of the rewrite sheet or on the surface of the core sheet.

  The thickness of the printing layer is 10 μm or less, and more preferably 3 μm or less in order to prevent distortion such as a step when the rewritable sheet and the core sheet are bonded together.

[Method of manufacturing non-contact IC recording medium]
The non-contact IC recording medium can be manufactured, for example, by a method including the following steps (1) to (6):
(1) A step of mixing a reversible thermosensitive composition and a binder resin and coating the mixture on a surface substrate to form a reversible thermosensitive recording layer;
(2) A step of coating the reversible thermosensitive recording layer with a paint for forming the anchor layer, if desired, to form the anchor layer;
(3) A step of applying a composition containing an ultraviolet curable resin onto the reversible thermosensitive recording layer or anchor layer to form a protective layer to obtain a rewritable sheet;
(4) The process of forming a printing layer by printing a pattern on the opposite side to the reversible thermosensitive recording layer of a surface base material, or providing a core base material and printing a pattern on a core base material;
(5) a step of laminating an inlet portion having an IC chip and an antenna pattern on a core substrate to form a core sheet; and (6) a reversible thermosensitive recording layer comprising a back substrate, a core sheet and a rewritable sheet. A step of laminating or bonding them so as to be on the front side to obtain a non-contact IC recording medium.

  Steps (1) to (3) can be performed using a coating machine such as a wire bar and a dryer. Step (4) can be performed using a printer and an ultraviolet irradiator. Steps (5) and (6) can be performed using a hot press.

[Ceramic non-contact IC recording media]
The non-contact IC recording medium can be in the form of a card according to the dimensions of a predetermined rewritable IC card. In that case, the card formed of the non-contact IC recording medium preferably has a thickness of 680 μm to 840 μm.
In order to prevent distortion or bending of the card, in the non-contact IC recording medium, it is preferable that the front substrate and the back substrate are formed of the same resin and adjusted to have the same thickness.

  The non-contact IC recording medium can be formed into a card by punching the non-contact IC recording medium into a card shape using a punching machine such as a punching die or a punching press.

  EXAMPLES The present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited to the examples.

[Transparent substrate]
In the examples, the following substrates were used:
Toyobo PET Cosmo Shine A4300 (thickness: 75 μm, 100 μm, or 125 μm); or Toyobo PET ester film E5201 (thickness: 75 μm, or 100 μm)

In the comparative examples, the following substrates were used:
Toyobo PET Cosmo Shine A4300 (thickness: 50 μm or 188 μm);
Toyobo PET ester film E5200 (thickness: 50 μm, 75 μm, 100 μm, or 125 μm); or Toyobo PET ester film E5201 (thickness: 50 μm, or 188 μm)

[Preparation of paint]
A reversible thermosensitive recording layer coating, an anchor layer coating, and a protective layer coating were prepared as follows. The following parts by weight are ratios calculated based on the weight of the material.

[Reversible thermosensitive recording layer paint]
The following materials were mixed and dispersed on a paint shaker for 18 hours to obtain a reversible thermosensitive recording layer paint:
Binder-DIC WBU-1218 (thermosetting acrylic resin) 20 parts by weight leuco dye-Yamamoto Kasei Blue 63 (leuco dye) 10 parts by weight developer-N- [3- (p-hydroxyphenyl) propiono] -N '-N-docosanohydrazide (developing color reducing agent) 40 parts by weight Curing agent-Takenate 500 (XDI curing agent) manufactured by Mitsui Chemicals 20 parts by weight UV absorber 10 parts by weight

[Anchor layer paint]
An anchor layer paint was obtained by blending the following materials:
-DIC ACRICID 44-198 72 parts by weight-Mitsui Chemicals D-110N (XDI curing agent) 18 parts by weight-Sipro Kasei Co., Ltd. Seasorb 703 10 parts by weight

[Protective layer paint]
An anchor layer paint was obtained by blending the following materials:
-DIC Unidic C7-164 (photocurable urethane-acrylate resin (solid content 50%)) 88 parts by weight-Silicia 436 (silica) by Fuji Silysia 6 parts by weight-KTL-4N (polytetrafluoroethylene made by Kitamura) ) 5 parts by weight ・ Fujikura Kasei AD-8719D (silicone oil) 1 part by weight ・ Diluent Toluene (Toluene was used in such an amount that the solid content of the protective layer paint was 20%)

[Production of rewrite sheet]
A rewrite sheet was prepared by sequentially forming a reversible thermosensitive recording layer, an anchor layer, and a protective layer as follows.

[Reversible thermosensitive recording layer]
A first transparent substrate was prepared as shown in Table 1 below. The reversible thermosensitive recording layer coating material was applied to a transparent substrate with a wire bar and dried at 100 ° C. for 2 minutes to form a reversible thermosensitive recording layer having a dry film thickness of 11 μm.

[Anchor layer]
The anchor layer coating was applied on the reversible thermosensitive recording layer with a wire bar and dried at 100 ° C. for 1 minute to form an anchor layer having a dry film thickness of 0.5 μm.

[Protective layer]
The protective coating is applied on the anchor layer with a wire bar, dried at 100 ° C. for 1 minute, and cured by irradiating with ultraviolet rays under the following conditions to have a dry film thickness of 5 μm. A protective layer was formed:
<Ultraviolet irradiation conditions>
UV lamp device: F600S manufactured by Fusion UV Systems Japan
Lamp output (UV irradiation intensity of protective layer): 120 W / cm or 240 W / cm
Conveyor (belt) speed: 30 m / min Number of passes: 1 pass

[Preparation of core sheet]
A core sheet having a configuration as shown in FIG. 2 was prepared.
Note that a PET-G sheet is used as a core substrate, and an antenna sheet including a non-contact type IC chip is sandwiched between two PET-G sheets.
Moreover, the thickness of the core sheet was adjusted in the range of 530 μm to 690 μm according to the thickness of the transparent substrate shown in FIG. 2 and Table 1 below and the thickness of the entire card.

[Print pattern]
Using an offset printing machine, the colorant-containing paint was applied to the core sheet substrate with a film thickness of 2 μm and cured by irradiation with ultraviolet rays under the following conditions to form a pattern printing layer:
<Ultraviolet irradiation conditions>
UV lamp device: F600S manufactured by Fusion UV Systems Japan
Lamp output (UV irradiation intensity): 240 W / cm
Conveyor (belt) speed: 30 m / min Number of passes: 1 pass

[Production of non-contact IC recording medium and creation of card]
A second transparent substrate that is formed of the same material as the first transparent substrate and has the same thickness was prepared.
As shown in FIG. 2, the rewrite sheet, the core sheet, and the second transparent base material are laminated so that the rewrite sheet prepared above is the uppermost layer, and bonded together by hot pressing, and a non-contact IC recording medium Was made.
Further, the non-contact IC recording medium was cut into a card form to produce a card.

[Evaluation procedure]
Using the card or rewrite sheet prepared above, the card was evaluated according to the following evaluation method and evaluation criteria.

[Evaluation method and evaluation criteria]
[Haze value]
Using a haze meter HR-100 (manufactured by Murakami Color Research Laboratory), the haze value was measured based on JISK-7105.

[Deformability of base material (curling property)]
Before producing the non-contact IC recording medium, the rewritable sheet was cut into a 10 cm square, and the height of the end of the transparent substrate (front substrate) was measured. The deformability (curlability) of the substrate was determined according to the following criteria:
○: The height is 5 cm or less.
X: The height exceeds 5 cm, or the transparent substrate curls into a cylindrical shape.

[Visibility]
Based on the visibility of Comparative Example 4 represented by the symbol “*” in Table 1 below, the visibility was determined as follows:
○: The pattern is the same as that of Comparative Example 4 or looks clearer than Comparative Example 4.
X: The pattern is not clearly seen as compared with Comparative Example 4.

[Print durability]
Using a printing machine TH-TCP (manufactured by Okura Engineering), printing and erasing were repeated 100 times, and printing durability was determined according to the following criteria:
○: The protective layer of the printing part does not peel off.
X: The protective layer of a printing part peels.

[Ethanol resistance]
Using a printing machine TH-TCP (manufactured by Okura Engineering Co., Ltd.), the card was printed once and then immersed in 100% ethanol for 24 hours. Subsequently, ethanol resistance was determined according to the following criteria:
○: Printing does not disappear.
×: Printing disappears.

[IC chip concealment]
The appearance of the card was visually observed to determine the concealment of the IC chip according to the following criteria:
○: The position of the IC chip cannot be visually confirmed.
X: The position of the IC chip can be confirmed visually.

[Heat-resistant]
Based on JISX6305-1, the heat resistance of the card was evaluated and the heat resistance of the card was determined as follows:
○: Within the range of the standard value of JISX6305-1.
X: It is out of the range of the standard value of JISX6305-1, and the card is deformed.

[Evaluation results]
For Examples 1 to 5 and Comparative Examples 1 to 10, the product name, thickness and haze value of the used transparent substrate, UV irradiation intensity of the protective layer, the thickness of the entire card, and the evaluation results of the card are shown in Table 1 below. Shown in
In Comparative Examples 1 and 5, the card was not evaluated because the first transparent base material curled significantly in the rewritable sheet and a card could not be produced.

  The present invention can be used for manufacturing a recording medium capable of performing both non-contact communication recording and reversible visible recording.

1 protective layer 2 intermediate layer 3 reversible thermosensitive recording layer (rewrite layer)
4 Front substrate (transparent substrate)
5 Print layer 6 Core sheet 7 Core substrate (core material)
8 IC chip 9 Back substrate (transparent substrate)

Claims (3)

A non-contact IC recording medium comprising a laminated protective layer, a reversible thermosensitive recording layer, a front substrate, a core sheet and a back substrate, and having a thickness of 680 μm to 840 μm,
The front substrate has a haze value of 4.5% or less and a thickness of 75 μm to 125 μm, and a printed layer is formed on the front substrate side of the core sheet,
Non-contact IC recording medium. A non-contact IC recording medium comprising a laminated protective layer, a reversible thermosensitive recording layer, a front substrate, a core sheet and a back substrate, and having a thickness of 680 μm to 840 μm,
The front substrate has a haze value of 4.5% or less and a thickness of 75 μm to 125 μm, and a printed layer is formed on the core sheet side of the front substrate,
Non-contact IC recording medium.   The non-contact IC recording medium according to claim 1, wherein the front substrate and the back substrate are formed of the same resin and have the same thickness.

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