JP3380363B2 - Thermoreversible recording medium - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates are those concerning the thermoreversible recording <br/> media bodies that can be repeated reversibly recorded and erased by thermal means.

[0002]

2. Description of the Related Art Thermoreversible recording materials have the property that the transparency of the thermoreversible recording materials (here, the transparency with respect to visible light will be discussed. The same applies hereinafter) changes depending on the thermal history. Therefore, for example, by using a thermal means such as a thermal head, the thermal history of a predetermined portion of the thermoreversible recording material is made different from that of the other portion, and the transparency of both portions is made different, thereby displaying the information. It can be done.

As a conventional example of such a thermoreversible recording material, for example, there is one disclosed in JP-A-55-154198.

In the thermoreversible recording material disclosed in such a conventional example, a behenic acid (docosanoic acid) is used as a matrix material composed of a polymer such as polyester or a resin.
It was composed by dispersing low molecular weight organic compounds such as.

As a concrete example of the above-mentioned characteristics, Japanese Patent Laid-Open No. 55-
Japanese Patent No. 154198 describes embodiments having the following configurations 1 to 4.

(1) A thermoreversible recording material containing a high molecular weight linear copolyester based on an aromatic dicarboxylic acid and an aliphatic diol and docosanoic acid is stable and transparent when heated to 72 ° C. and cooled. Showed sex. This is 77
It was possible to return to a cloudy state only by reheating to a temperature above ° C.

(2) A thermoreversible recording material containing a copolymer of vinylidene chloride and acrylonitrilo, docosanoic acid, and a fluorad lubricant for improving fluidity is 63 ° C.
When it was heated to and cooled, it showed stable transparency. It could only be returned to the opaque state by reheating to a temperature above 74 ° C.

(3) A thermoreversible recording material containing a copolymer of vinyl chloride and vinyl acetate and docosanol is 68 ° C.
When it was heated up to and cooled, it showed stable transparency.
It could only be returned to a cloudy state by reheating to temperatures above 70 ° C.

(4) The thermoreversible recording material containing polyester and docosanoic acid showed stable transparency when heated to 72 ° C. and cooled. It could only be returned to a cloudy state by reheating to a temperature above 77 ° C.

However, in the above thermoreversible recording material, since a thermal head or the like is used during image formation, when the surface is heated by the thermal head or the like, the recording layer is damaged or the recording layer composition contains the thermal head. On the
When recording and erasing were repeated, the recording layer deteriorated and image formation became extremely difficult. Therefore, in order to improve these drawbacks, an ultraviolet curable resin or an electron beam curable resin (see JP-A-2-566) or a silicone-based graft polymer (see JP-A-2-86491) is used as a protective layer. The thermoreversible recording medium used has been proposed.

[0011]

However, although details will be described later with reference to comparative examples, in the conventional thermoreversible recording medium, the resin as the main component of the thermoreversible recording layer and the resin used for the protective layer are used. However, when the protective layer is formed on the thermoreversible recording layer, heating is performed to remove the solvent and to cure the thermoreversible recording layer. The medium was warped, and in severe cases, the protective layer was cracked or peeled. further,
Heating is also performed when erasing image information, but for the same reason, the thermoreversible recording medium was warped, and in severe cases, the protective layer was cracked or peeled.

Further, in the conventional thermoreversible recording medium, since the resin as the main component of the thermoreversible recording layer and the resin used for the protective layer are different, the adhesion between the thermoreversible recording layer and the protective layer is sufficient. However, when recording and erasing are repeated, the thermoreversible recording layer and the protective layer are peeled off.

The present invention eliminates the above problems and makes the recording medium free from warpage of the recording medium and cracking or peeling of the protective layer by using the same resin as the main component of the thermoreversible recording layer and the resin used for the protective layer. Thermoreversible recording medium with good adhesion between the protective layer and the protective layer
Intended to provide the body .

[0014]

In order to achieve the above object, the present invention provides: (1) A thermoreversible recording material comprising a thermoreversible recording material containing at least a matrix material and an organic low molecule and having a transparency that changes depending on a thermal history. Recording layer, a support for supporting the thermoreversible recording layer, and a thermoreversible recording medium provided with a protective layer on the side opposite to the support, directly or via an intermediate layer, As the protective layer, polyvinyl acetal and an ultraviolet curable resin (provided that it is cured with a curing agent) are used.

(2) In the thermoreversible recording medium described in (1) above, polyvinyl acetal and an ultraviolet curable resin used as the protective layer (provided that it is cured with a curing agent).
And the compounding ratio of polyvinyl acetal: UV curable resin is 1000: 1 to 1: 2.

(3) In the thermoreversible recording medium according to the above (1), the thermoreversible recording material uses polyvinyl butyral as a matrix material, and a saturated carboxylic acid or a derivative of this saturated carboxylic acid is used as an organic low molecule. At least one selected from the group is included.

(4) In the thermoreversible recording medium according to the above (1), the thermoreversible recording material uses polyvinyl acetal or a matrix material containing polyvinyl acetal as a main component as a matrix material, and as an organic low molecule. It comprises at least one selected from the group of saturated carboxylic acids and derivatives of this saturated carboxylic acid.

(5) In the thermoreversible recording medium according to (4) above, in the thermoreversible recording medium according to claim 4,
As an additive to the polyvinyl acetal contained in the thermoreversible recording layer, an epoxy resin, a phenol compound, an epoxy compound, an aldehyde compound, an isocyanic acid compound, an epoxy resin (but cured with a curing agent), an ultraviolet curable resin (provided that Cured with a curing agent) , or organosiloxane (but crosslinked)
To use.

(6) In the thermoreversible recording medium described in (1) above, at least one of the support and the protective layer is made of a material transparent to visible light.

(7) In the thermoreversible recording medium according to (1) above, when the intermediate layer is used, the intermediate layer is thermoreversible from at least the reflective layer, the light absorbing layer, the enhancing layer and the printing layer. The recording medium is formed as one or more layers selected depending on the direction of light incident on the recording medium and the viewing direction of the recording formed on the thermoreversible recording medium.

(8) In the thermoreversible recording medium described in (1) above, the support is made of a material having transparency to visible light, and the support is provided on the side opposite to the thermoreversible recording layer. Is provided with a reflective layer or a light absorbing layer.

(9) In the thermoreversible recording medium described in (1) above, the support has a property of changing the traveling direction of light incident on the support.

(10) Any one of the above (1) to (9)
In the thermoreversible recording medium described in the item 1, a recording layer is provided separately from the thermoreversible recording layer.

In particular, the thermoreversible recording medium of the present invention is such that polyvinyl acetal and an ultraviolet curable resin (provided that it is cured with a curing agent) are used as the protective layer. It should be noted that the case where the UV curable resin before curing remains in the protective layer is also included.

In the thermoreversible recording medium of the present invention, since the resin as the main component of the thermoreversible recording layer and the resin used for the protective layer are the same, warpage, cracking and peeling of the protective layer can be suppressed. Further, the adhesiveness between the thermoreversible recording layer and the protective layer was sufficient, and the problem that the thermoreversible recording layer and the protective layer were separated when recording and erasing were repeated could be solved.

The UV curable resin used here is not limited to this, but the UV curable resin is
It consists of three components.

(1) Polymerizable oligomer (monomer): The main component in the ultraviolet curable resin composition component.

(2) Photoreaction initiator: Absorbs ultraviolet rays to initiate a polymerization reaction. The ultraviolet curable resin used here is not limited to this, but includes (a) polymerizable oligomer (monomer) phenol ethylene oxide modified acrylate, nonylphenol ethylene oxide modified acrylate, nonylphenol propylene oxide modified acrylate, and 2-ethylhexyl carbitol. Acrylate, ω
-Carboxy-polycaprolactone acrylate, ω-
Carboxyacryloyloxyethyl phthalate, acrylic acid dimer, 2-hydroxy-3-phenoxypropyl acrylate, etc. monoacrylate tripropylene glycol diacrylate, tetraethylene glycol diacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, dipentaerythritol Polyol polyacrylate such as hexaacrylate Modified propylene oxide of trimethylolpropane triacrylate, modified ethylene oxide and lactone of isocyanuric acid, modified ethylene oxide of bisphenol A, etc. Modified polyol polyacrylate αω-diacryloyl- (bisethylene glycol)-
Polyester acrylates such as phthalate, αω-tetraacryloyl- (bistrimethylolpropane) -tetrahydrophthalate, αω-hexaacryloyl- (bispentaerythritol) -adipate, epoxy acrylate, urethane acrylate, polyether acrylate, silicon acrylate, vinyl ether compound , Phosphazene compounds, and the like.

Further, the commercially available UV-curable resin is not limited to these, and examples thereof include Aronix [trademark, polyester acrylate-based and urethane acrylate-based, Toa Synthetic Chemical Industry Co., Ltd.], viscoat [trademark] , Polyester acrylate type and epoxy acrylate type and urethane acrylate type, Osaka Organic Chemical Industry Co., Ltd.], Ebecry1 [trademark, polyester acrylate type and epoxy acrylate type and urethane acrylate type, UCB chemical], lipoxy [trademark, epoxy acrylate type, Showa Highpolymer Co., Ltd.], N
K ester [trademark, epoxy acrylate-based and urethane acrylate-based, Shin-Nakamura Chemical Co., Ltd.], Blemmer [trademark, epoxy methacrylate-based, NOF CORPORATION], Kayarad [trademark, epoxy acrylate-based, Nippon Kayaku (stock) )], Epoxy ester [trademark, epoxy acrylate-based and epoxy methacrylate-based, Kyoeisha Oil and Fat Chemical Co., Ltd.], Denacol [trademark, epoxy acrylate-based and epoxy methacrylate-based, Nagase Sangyo Co., Ltd.], art resin [trademark, urethane Acrylate-based, Negami Kogyo Co., Ltd., XP [trademark, urethane acrylate-based, Nippon Synthetic Chemical Industry Co., Ltd.] Chemlink [trademark, urethane acrylate-based, Sart
PPZ [trademark, phosphazene type, Idemitsu Petrochemical Co., Ltd.] Iupimer [trademark, polyester acrylate type and urethane acrylate type, Mitsubishi Yuka Co., Ltd.] Aikatron [trademark, polyester acrylate type and epoxy acrylate type and urethane acrylate type] ,
Aika Kogyo Co., Ltd.] Fujihard [trademark, polyester acrylate-based and epoxy acrylate-based and urethane acrylate-based, Fujikura Kasei Co., Ltd.] S-COAT UV [trademark, Sekisui Chemical Co., Ltd.] and the like.

(B) Photoinitiator Benzoin ether type 1-hydroxycyclohexyl phenyl ketone such as isopropyl benzoin ether, isobutyl benzoin ether, isomethyl benzoin ether, isoethyl benzoin ether, and ketal type 2-hydroxy-type such as benzyl dimethyl ketal. 2-methyl-propiophenone, 4-
Acetophenone-based benzophenones such as isopropyl-2-hydroxy-2-methylpropiophenone, benzophenone-based 2-methylthiooxanthones such as methyl O-benzoylbenzoate, and thiooxanthone-based compounds such as 2-chlorothiooxanthone. .

A reactive diluent is used in combination with a polymerizable oligomer (monomer) to lower the viscosity of the composition and improve the physical properties of the cured product. Although not limited, (reactive diluent) of a monofunctional group such as 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, N-vinyl-2-pyrrolidone isobornyl acrylate, 2-hydroxyethyl acroyl phosphate, etc. Monofunctional trimethylolpropane triacrylate, penta, such as 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, diethylene glycol diacrylate, thioglycol diacrylate Erythritol triacrylate, dipe Data hexaacrylate, those such as polyfunctional group such as triallyl isocyanurate.

In addition, additives such as a leveling agent, a filler, a polymerization inhibitor, a thermosetting catalyst and an anaerobic catalyst may be used depending on the purpose. Further, the leaving time and the heat treatment conditions referred to in the present invention are determined according to the kind of the ultraviolet curable resin so that the desired reaction can proceed.

As the thermoreversible recording material used here, polyvinyl butyral (see JP-A-4-363294), polyvinyl acetal (see JP-A-6-48032), polyvinyl acetal and epoxy are used as matrix materials. Resin or phenol compound or epoxy compound or aldehyde compound or isocyanic acid compound (see JP-A-6-64318), polyvinyl acetal and epoxy resin (provided that it is cured with a curing agent) (see Japanese Patent Application No. 6-70291). ,
Polyvinyl acetal and ultraviolet curable resin (however cured with a curing agent) (see Japanese Patent Application No. 6-216922), polyvinyl acetal and organosiloxane (however crosslinked) (see Japanese Patent Application No. 6-231515) Used.

As the saturated carboxylic acid which can be used, monocarboxylic acid having at least 10 carbon atoms, dicarboxylic acid having at least 10 carbon atoms, derivative of monocarboxylic acid having at least 10 carbon atoms, carbon Derivatives of dicarboxylic acid having a number of at least 10 (JP-A-4-363294, JP-A-6-48032, JP-A-6-64318, and Japanese Patent Application No. 6-702).
No. 91, Japanese Patent Application No. 6-216922, No. 6 Japanese Patent Application
No. 231515) is preferable.

The reason why each of the above carboxylic acids has at least 10 carbon atoms is that the other ones are in a liquid state at room temperature and thus do not meet the purpose of the present invention.

The mixing ratio of the above-mentioned matrix material to the saturated carboxylic acid and its derivative is such that when the saturated carboxylic acid and its derivative are included in a weight ratio of more than 1: 2, a thermoreversible recording material is obtained. The film becomes difficult, and if it is less than 20: 1, the thermoreversibility becomes small, so 1: 2 to 20 :.
It is preferably within the range of 1.

In the first invention, the mixing ratio of the polyvinyl acetal used as the protective film and the ultraviolet curable resin (cured) is the same as the charging composition (polyvinyl acetal and the ultraviolet curable resin before curing). It has been confirmed that the effect of the present invention is exhibited when the both are mixed at a ratio of 1 part by weight of the ultraviolet curable resin before curing to 1000 parts by weight of polyvinyl acetal.

Further, the upper limit of mixing the UV curable resin is within a range in which warpage, cracking and peeling of the protective layer can be suppressed, but at least 1 part by weight of polyvinyl acetal is 2 parts by weight of the UV curable resin before curing. It has been confirmed that cracking and peeling of the protective layer can be suppressed even when the two are mixed at a ratio of parts. From these facts, it is considered that the mixing ratio of the polyvinyl acetal and the ultraviolet curable resin before curing is, by weight, 1000: 1 to 1: 2, and more preferably about 100: 1 to 1: 1.

In the first aspect of the invention, the inclusion of polyvinyl acetal used as a protective film and an ultraviolet curable resin (provided that it is cured) is not limited to these cases alone, but in addition to these, thermoreversible recording is also possible. It also means the case where other substances such as a substance that improves the film quality of the material and a substance that improves the lubricity are included.

A thermoreversible recording medium is provided as the first aspect of the present invention. Specifically, the medium is, for example, a prepaid card such as a telephone card, an orange card, a highway card, a postpaid card, or a point. Cards, labels used in various fields, signboards of signboard systems, or word processors and facsimile recording papers that employ a thermal recording system,
It can be a sheet of a projection image forming apparatus such as an overhead projector or a slide.

[0041]

As is apparent from the experimental results described below, [I] the thermoreversible recording medium of the first invention of the present invention: (1) The display contrast is lowered when recording and erasing are repeated. It is possible to obtain a thermoreversible recording medium that is less likely to occur than in the past.

(2) In addition to having a high surface hardness, it is thermally strong,
A medium resistant to mechanical shock from the outside can be obtained. Therefore, the restriction on the temperature control of the thermal means such as the thermal head can be relaxed as compared with the conventional case.

(3) Since the warp is reduced, the recording device,
When repetitive recording and erasing are performed by the erasing device, there is no possibility of being caught in the device or being unable to be inserted due to the warp.

(4) It is not necessary to heat the thermoreversible recording medium at the time of preparation (because curing is due to irradiation of ultraviolet rays), and a thermoreversible recording medium in which deterioration of the recording layer due to heating is small can be obtained.

[0045]

Embodiments of the present invention will be described in detail below with reference to the drawings.

It should be noted that the drawings used for the description are only schematically shown so that the present invention can be understood. Further, it is understood that the materials and numerical conditions used in this example are merely examples within the scope of the present invention, and therefore the present invention is not limited to these materials and numerical conditions. I want to.

[A] The first invention (thermoreversible recording medium) will be described.

(1) First, the first embodiment of the first invention (the thermoreversible recording medium) will be described.

As a polyvinyl acetal as a protective layer, S-REC KS-1 (trademark) of Sekisui Chemical Co., Ltd.
Iupimer SA-1002 [trademark, polyester acrylate type, Mitsubishi Petrochemical Co., Ltd.] is prepared as a polymerizable oligomer (monomer) of the ultraviolet curable resin, and benzophenone is prepared as a photoreaction initiator. A recording layer prepared by using polyvinyl acetal and behenic acid is prepared as the recording layer.

Then, S-REC KS-1, 90 parts by weight, Iupimer SA-1002, 10 parts by weight, and benzophenone, 2 parts by weight were dissolved in 900 parts by weight of tetrahydrofuran (hereinafter abbreviated as THF) to form a protective layer. Prepare the coating solution of.

In the liquid thus obtained (which will be the coating liquid for the thermoreversible recording medium), the photoreaction initiator is irradiated with ultraviolet rays (wavelength 100 to 400 nm) to generate radicals or cations. The radicals or cations initiate and grow the polymerization of the polymerizable oligomer (monomer), and finally solidify. This reaction starts from the moment when the polymerizable oligomer (monomer) and the photoreaction initiator are mixed, and it takes a few hours to a few days under normal light (sunlight), and a few seconds under a mercury lamp such as an ultraviolet curing device. Solidification is completed within a few minutes.

By the way, if the liquid substance itself is solidified, it becomes impossible to apply the protective layer to the recording layer, so that the desired thermoreversible recording medium cannot be formed. In the case of the first embodiment, it takes several days under ordinary light (sunlight) at room temperature until the liquid substance solidifies, so that it does not hinder the application, but In some of the other embodiments, solidification of the liquid material itself occurs relatively quickly, and therefore care may be required.

In consideration of these points, when preparing the liquid material, a material other than the UV curable resin (here,
(Polyvinyl acetal) is placed in a solvent (here, THF), and the ultraviolet curable resin [polymerizable oligomer (monomer), photoreaction initiator] is added last. Alternatively, it is desirable to take measures such as winding a shield (black film or the like) so that the ultraviolet rays do not hit the liquid material.

Next, in this first embodiment, as shown in FIG. 1, a polyethylene terephthalate substrate is prepared as the support 21 in this case. Then, a recording layer prepared by using polyvinyl acetal and behenic acid is prepared as a recording layer on the support 21. The above coating solution is applied to a predetermined thickness by the bar coating method.

Next, this sample is heat-treated at a predetermined temperature for a predetermined time, for example, to give a transparent protective layer (hereinafter simply referred to as protective layer 29
I get). The heat treatment here is mainly performed under the condition that the THF used for preparing the coating solution can be removed. Here, heat treatment is performed at a temperature of 120 ° C. for a predetermined time in an air atmosphere. Here, as a coating method, a roll coating method,
Other suitable methods such as a gravure coating method and a blade coating method can also be used.

Next, the protective layer 29 is cured and irradiated with ultraviolet rays to obtain a desired medium. Here, using an ultraviolet irradiation device [(manufactured by Eye Graphics Co., Ltd.),
Irradiation was performed at 80 W / cm for 2 minutes. Here, the discharge lamp method is used to irradiate the ultraviolet rays, but the medium is also cured by the ultraviolet irradiation of other flash methods, laser methods, and electrodeless lamp methods. Furthermore, even in normal light (sunlight),
It hardens in a few days and can be left alone.

The support 21 and the layer of the thermoreversible recording material formed on the support 21 (hereinafter referred to as the thermoreversible recording layer 25) are formed on the thermoreversible recording layer 25. The structure composed of the protective layer 29 can be said to be the thermoreversible recording medium 20 having the most basic structure (the thermoreversible recording medium of the first embodiment). In the thermoreversible recording medium 20, heat is applied to the thermoreversible recording layer 25 by heating the thermoreversible recording layer 25 from the protective layer 29 side through the protective layer 29, as well as the support 21. If the thermal conductivity is good, the method of heating the thermoreversible recording layer 25 from the support 21 side through the support 21 can be adopted.

Further, in FIG. 1, the arrow with the letter "light" indicates the state of incidence of light on the thermoreversible recording medium 20, and the arrow with the letter "eye" indicates the thermoreversible recording. The direction in which an image formed on the medium 20 is viewed by a person is shown, and the arrow indicating the word "heating" indicates the direction in which heat is applied by the above two methods. (Hereinafter, the same applies to the thermoreversible recording medium after FIG. 1) The example of FIG. 1 is an example in which an image is recognized depending on the presence or absence of the reflected light from the thermoreversible recording medium 20. Of course, in the configuration of FIG.
Light may be made incident on the thermoreversible recording medium 20 from the side of the support 21 so that an image may be recognized depending on the presence or absence of transmitted light.

Next, the characteristics of the change in transparency with respect to the thermal history of the thermoreversible recording layer 25 will be examined. As a result, when the thermoreversible recording layer 25 is heated to a temperature T ₂ or higher and then rapidly cooled (for example, 50 ° C./second or higher) as shown in FIG. In the case of showing the maximum transparency, when it is heated to T ₁ (T ₁ <T ₂ ) or more and T ₂ or less and then rapidly cooled (for example, 50 ° C./sec or more), or T
_When heated to an arbitrary temperature Tn of ₁ or more (however, it does not exceed the softening point of polyvinyl acetal (200 ° C in S-REC KS-1)) and then gradually cooled (for example, shows less than 50 ° C / sec) (Fig. 1 has a heat history-transparency characteristic of exhibiting the minimum transparency (white turbid state), and T
It was found that ₁ = 80 ° C. and T ₂ = 120 ° C. were shown. That is, in the case of the thermoreversible recording medium of the first example, the temperature at which the transparent state can be formed may be in the range of 120 to 200 ° C, and the range is 80 ° C.
The temperature at which the cloudy state can be formed may be in the range of 80 to 200 ° C, and the range is 120 ° C.

Further, the transmittance of light having a wavelength of 550 nm (visible light) in each of the transparent state and the cloudy state of the thermoreversible recording layer of the first embodiment is obtained. The transmittance in the former state was 80%, and the transmittance in the latter state was 4%. The contrast obtained from the ratio of these transmittances is 2
It becomes 0.

With respect to the thermoreversible recording layer of the first embodiment, a treatment of making it transparent by heating it to a temperature of 140 ° C. and then rapidly cooling it, and then a condition of heating it again to a temperature of 140 ° C. and then gradually cooling it. The recording / erasing process in which the process of making the white turbidity is one cycle is repeated 100 cycles. And
After 100 cycles, the transmittance is measured again to calculate the contrast. It was found that the contrast at this time was 20 as in the initial value.

The surface hardness of the thermoreversible recording medium of the first example determined by the pencil hardness test method (JIS K5401) was as hard as 3H and mechanically resistant to scratches.

Further, in order to measure the warp of the thermoreversible recording medium of the first embodiment, the thermoreversible recording medium of the first embodiment is card-shaped (length 54 mm, width 86 mm, JIS).
Recording and erasing processing in which one cycle consists of punching into a standard "die", recording an image (characters) with a thermal head, and then heating again to a temperature of 140 ° C and then turbidizing under the conditions of slow cooling. Is repeated for 100 cycles.
Then, after 100 cycles, as shown in FIG.
Place on the surface plate 15 and use the gap gauge to measure the long side (86m
m) and the gap in the short side direction (54 mm) were measured,
It was a good value of 0.2 mm in both the long side direction and the short side direction.

Next, second to eighth embodiments of the first invention (thermoreversible recording medium) will be described.

The same procedure as in the first embodiment was carried out except that the polymerizable oligomer (monomer) in the first embodiment was changed to the following. That is, (2) In the second example, the polymerizable oligomer (monomer) of the first example was added to Uupimer AU-1100 [trademark,
Urethane acrylate type, Mitsubishi Petrochemical Co., Ltd.].

(3) In the third example, the polymerizable oligomer (monomer) of the first example was replaced with PPZ [trademark, phosphazene type, Idemitsu Petrochemical Co., Ltd.].

(4) In the fourth embodiment, the polymerizable oligomer (monomer) of the first embodiment is replaced with Denacol DA-8.
11 [trademark, epoxy acrylate type, Nagase & Co., Ltd.].

(5) In the fifth embodiment, the polymerizable oligomer (monomer) of the first embodiment is added to Denacol DM-8.
11 [trademark, epoxy methacrylate type, Nagase & Co., Ltd.].

(6) In the sixth embodiment, the polymerizable oligomer (monomer) of the first embodiment is added with bis coat 700.
[Trademark, polyester acrylate type, Osaka Organic Chemical Industry Co., Ltd.].

(7) In the seventh embodiment, the polymerizable oligomer (monomer) of the first embodiment is mixed with Kayarad R-16.
7 [Trademark, epoxy acrylate, Nippon Kayaku Co., Ltd.]
Replaced with.

(8) In the eighth embodiment, the polymerizable oligomer (monomer) of the first embodiment is replaced with Icatron Z-6.
61 [trademark, polyester acrylate type, Aika Kogyo KK].

The drying conditions and the ultraviolet irradiation conditions for curing in the above second to eighth embodiments are the same as those in the first embodiment.

Further, it was found that the initial contrast and the contrast after 100 cycles of the transparentizing treatment and the clouding treatment were both 20. Furthermore, the surface hardness obtained by the pencil hardness test method (JIS K5401) is
In the second to eighth embodiments, 3H and 2 respectively.
It was found to be H, 3H, 2H, 2H, 2H, 3H.

In the second to eighth embodiments, the gap after the recording / erasing process is repeated 100 cycles is (0.3 mm, in the long side direction and the short side direction), respectively.
0.3 mm), (0.2 mm, 0.2 mm), (0.2
mm, 0.2 mm), (0.3 mm, 0.2 mm),
(0.3mm, 0.3mm), (0.2mm, 0.2m
m), (0.1 mm, 0.1 mm).

Next, ninth to seventeenth embodiments of the first invention (thermoreversible recording medium) will be described.

The same procedure as in the first example was carried out except that the recording layer prepared by using the polyvinyl acetal and behenic acid in the first example was changed to the following. That is, (9) in the ninth embodiment, a recording layer prepared by using the polyvinyl acetal and behenic acid of the first embodiment is a polyvinyl butyral S-REC B [trade name, manufactured by Sekisui Chemical Co., Ltd.].
Then, the saturated carboxylic acid and its derivative, behenic acid, were replaced.

(10) In the tenth embodiment, the recording layer prepared by using the polyvinyl acetal and behenic acid of the first embodiment is replaced with the polyvinyl acetal S-REC KS.
-1 [trade name, manufactured by Sekisui Chemical Co., Ltd.], epoxy resin Epomic R309 [trade name, manufactured by Mitsui Petrochemical Industry Co., Ltd.], and saturated carboxylic acid and its derivative, behenic acid. I replaced it.

(11) In the eleventh embodiment, a recording layer prepared by using the polyvinyl acetal of the first embodiment and behenic acid is replaced by a polyvinyl acetal S-REC KS.
-1 [trade name, manufactured by Sekisui Chemical Co., Ltd.], phenol resin, Priofen 5030 [trade name, manufactured by Dainippon Ink and Chemicals, Inc.], and saturated carboxylic acid and its derivative, phenene. Replaced with acid.

(12) In the twelfth embodiment, the recording layer prepared by using the polyvinyl acetal and behenic acid of the first embodiment is replaced with the polyvinyl acetal S-REC KS.
-1 [trade name, manufactured by Sekisui Chemical Co., Ltd.], an epoxy compound, Denacol EX-111 [trade name, manufactured by Nagase Kasei Co., Ltd.], and saturated carboxylic acid and its derivative, behenic acid. Replaced with.

(13) In the thirteenth embodiment, the recording layer prepared by using the polyvinyl acetal of the first embodiment and behenic acid is replaced with the polyvinyl acetal S-REC KS.
-1 [trade name, manufactured by Sekisui Chemical Co., Ltd.], aminobenzaldehyde as an aldehyde compound, and saturated carboxylic acid and behenic acid as a derivative thereof.

(14) In the fourteenth embodiment, the recording layer prepared by using the polyvinyl acetal and behenic acid of the first embodiment is replaced with the polyvinyl acetal S-REC KS.
-1 [trade name, manufactured by Sekisui Chemical Co., Ltd.], octadecyl isocyanate as an isocyanate compound, and behenic acid as a saturated carboxylic acid and its derivative.

(15) In the fifteenth embodiment, the recording layer prepared by using the polyvinyl acetal and behenic acid of the first embodiment is replaced with the polyvinyl acetal S-REC KS.
-1 [trade name, Sekisui Chemical Co., Ltd.], epoxy resin Epomic R362 [trade name, Mitsui Petrochemical Co., Ltd.], curing agent butylamine, saturated carboxylic acid and its derivatives Was replaced by behenic acid.

(16) In the sixteenth embodiment, the recording layer prepared by using the polyvinyl acetal and behenic acid of the first embodiment is replaced with the polyvinyl acetal S-REC KS.
-1 [trade name, manufactured by Sekisui Chemical Co., Ltd.], an ultraviolet curable resin, UPIMER SA-1002 [trade name, manufactured by Mitsubishi Petrochemical Co., Ltd.], and a photoreaction initiator, benzophenone,
The saturated carboxylic acid and its derivative, behenic acid, were substituted.

(17) In the seventeenth embodiment, the recording layer prepared by using the polyvinyl acetal and behenic acid of the first embodiment is replaced with the polyvinyl acetal S-REC KS.
-1 [trade name, manufactured by Sekisui Chemical Co., Ltd.], ESTB-7000 (trade name, TSB Development Center) which is an organosiloxane, and saturated carboxylic acid and its behenic acid derivative.

The dry state of the protective layers of the ninth to seventeenth examples and the ultraviolet curing conditions for curing are the same as those of the first example.

Further, the initial contrast and the contrast after 100 cycles of the clearing treatment and the clouding treatment are:
It was found that both were 20. Further, the surface hardness obtained by the pencil hardness test method (JIS K5401) is (long side direction, in the ninth to seventeenth examples).
2H, 2H, 2H, 3H, 2 respectively
It was found to be H, 2H, 4H, 4H, 4H. The gap after 100 cycles of recording / erasing is
In the ninth to seventeenth examples, (0.2
mm, 0.2 mm), (0.3 mm, 0.2 mm),
(0.3mm, 0.3mm), (0.2mm, 0.2m
m), (0.1 mm, 0.1 mm), (0.2 mm,
0.2mm), (0.4mm, 0.3mm), (0.4
mm, 0.4 mm), (0.4 mm, 0.3 mm).

Next, eighteenth to twentieth embodiments of the first invention (thermoreversible recording medium) will be described.

The same procedure as in the first example was carried out except that the compounding ratio of the polyvinyl acetal and the ultraviolet curable resin in the first example was changed to the following. That is, (18) In the eighteenth example, the mixing ratio of the polyvinyl acetal and the ultraviolet curable resin of the first example was 100 parts by weight of S-REC KS-1, 0.12 parts by weight of Uupimer SA-1002, benzophenone, It was replaced with 0.02 parts by weight and 900 parts by weight of tetrahydrofuran.

(19) In the nineteenth embodiment, the mixing ratio of the polyvinyl acetal of the first embodiment and the ultraviolet curable resin is S-REC KS-1,50 parts by weight and Uupimer SA.
−1002, 50 parts by weight, benzophenone, 10 parts by weight, 900 parts by weight of tetrahydrofuran were used instead.

(20) In the twentieth embodiment, the mixing ratio of the polyvinyl acetal of the first embodiment and the ultraviolet curable resin is S-REC KS-1,25 parts by weight and Uupimer SA.
-1002,75 parts by weight, benzophenone, 15 parts by weight, and 900 parts by weight of tetrahydrofuran were replaced.

The drying conditions and the ultraviolet irradiation conditions for curing in the eighteenth to twentieth embodiments were the same as in the first embodiment.

Further, it was found that the initial contrast and the contrast after 100 cycles of the clearing treatment and the clouding treatment were both 20. Furthermore, the surface hardness obtained by the pencil hardness test method (JIS K5401) is
In the 18th to 20th embodiments, H and 4
It was found to be H and 6H. 10 recording / erasing processes
The gap after repeating 0 cycles is 18th Example-2nd.
In Example 0, (long side direction, short side direction) are (0 mm, 0 mm), (0.4 mm, 0.3 mm),
It was found to be (0.8 mm, 0.6 mm).

Comparative Example [1] Comparative Example 1 Further, in the first example, only the thermoreversible recording medium not forming the protective layer of the present invention, that is, only the recording layer prepared using polyvinyl acetal and behenic acid To make. Then, the characteristics of this layer are measured in exactly the same manner as in the first embodiment.

Further, the heat-reversible recording layer of Comparative Example 1 was made transparent by heating to 140 ° C. and then rapidly cooling, and then heated again to 140 ° C. and then gradually cooling. The recording / erasing process in which the process of making the white turbidity is one cycle is repeated 100 cycles. And
After 100 cycles, the transmittance is measured again to calculate the contrast. At this time, the transparent state was 80% and the transmittance in the cloudy state was 20%. Therefore, it was found that the contrast was 4, which was worse than the initial value of 20.

Further, in order to measure the warp of the thermoreversible recording medium of Comparative Example 1, the thermoreversible recording medium of Comparative Example 1 was formed into a card shape (length 54 mm, width 86 mm, JIS standard “mold”). The recording / erasing process is repeated 100 times, in which the process of punching and recording an image (characters) with a thermal head and the process of clouding under the condition of being heated again to a temperature of 140 ° C. and then gradually cooled are one cycle. Then, after 100 cycles, as shown in FIG. 3, it is placed on the surface plate 15 and the gap gauge is used to measure the long side direction (86 mm).
When the gap in the short side direction (54 mm) was measured, it was a good value of 0 mm in both the long side direction and the short side direction.

The pencil hardness test method (JIS K540
It was found that the surface hardness obtained by 1) was worse than either F or the present invention, and the thermoreversible recording medium was vulnerable to mechanical damage.

[2] Comparative Example 2 Further, the mixing ratio of the polyvinyl acetal of the first example and the ultraviolet curable resin was as follows: S-REC KS-1,0 parts by weight, Iupimer SA-1002, 100 parts by weight, benzophenone, 20 parts by weight. Parts, and 900 parts by weight of tetrahydrofuran, the protective layer coating solution of Comparative Example 2 was prepared in exactly the same manner as in Example 1, and recording was performed using polyvinyl acetal and behenic acid as the recording layer. Prepare layers. Then, the protective layer is formed as in the first embodiment. Each of these characteristics is measured.

The thermoreversible recording layer of Comparative Example 2 was heated to a temperature of 140 ° C. and then rapidly cooled, and then transparentized, and then heated again to a temperature of 140 ° C. and then gradually cooled. The recording / erasing process in which the process of making the cloudy condition is one cycle is repeated 100 cycles. Then, after 100 cycles, the transmittance is measured again to calculate the contrast. At this time, the transmittance in the transparent state was 80%, and the transmittance in the cloudy state was 4%. Therefore, the contrast was a good value of 20.

Further, in order to measure the warp of the thermoreversible recording medium of Comparative Example 2, the thermoreversible recording medium of Comparative Example 1 was formed into a card shape (length 54 mm, width 86 mm, JIS standard “mold”). The recording / erasing process is repeated 100 times, in which the process of punching and recording an image (characters) with a thermal head and the process of clouding under the condition of being heated again to a temperature of 140 ° C. and then gradually cooled are one cycle. Then, after 100 cycles, as shown in FIG. 3, it is placed on the surface plate 15 and the gap gauge is used to measure the long side direction (86 mm).
And the gap in the short side direction (54 mm) was measured, and it was found that the long side direction and the short side direction warp violently at 10.0 mm and 8.0 mm, respectively.

In such a warped thermoreversible recording medium, when it is used as a prepaid card in actual use, it becomes impossible to insert it into the recording device due to the warp.
Although there is no precise regulation, it is desirable that the warp in the long side direction and the short side direction is (1.0 mm, 0.7 mm) or less in each of the long side direction and the short side direction.

Furthermore, the pencil hardness test method (JIS K540
The surface hardness determined by 1) was found to be 6H.

[0102]

[Table 1]

[0103]

[Table 2]

Further, here, a thermoreversible recording medium is provided. Specifically, the medium here is, for example, a prepaid card such as a telephone card, an orange card, a highway card, a postpaid card, a point card. Or, a label used in various fields, a signboard of a signboard system, or a word processor or a recording paper for a facsimile which adopts a thermal recording system, and further,
It can be a sheet of a projection image forming apparatus such as an overhead projector or a slide.

The first embodiment has been described above with reference to FIG. That is, it has a structure in which the thermoreversible recording layer 25, the support 21 for maintaining the thermoreversible recording layer 25, and the protective layer 29 are laminated. Here, the support 21 may have any suitable shape, constituent material, and film thickness according to the design of the thermoreversible recording medium 20. For example, a support that is transparent to visible light, one that reflects part or all of visible light, or one that absorbs part or all of visible light can be the support 21.

In this case, by selectively heating the thermoreversible recording layer 25 from the thermoreversible recording layer 25 side, the transparent portion and the cloudy portion can be selectively formed on the thermoreversible recording layer 25. . In other words, if the support 21 is made of a material having good thermal conductivity in addition to being capable of displaying, the support 21
The thermoreversible recording layer 25 is heated via the support 21 by contacting the heating means with the transparent means and the cloudy portion from the support 21 side (from the back side of the thermoreversible recording medium 20). It can be selectively formed (display can be done).

In the case where the display can be made also from the support 21 side, when the thermoreversible recording medium 20 is used as the display screen of the display device, a person can see the thermoreversible recording medium 20. There is an advantage that a desired display can be performed without disposing a heating means. When the display can be performed from the side of the support 21, depending on the design, other advantages can be obtained in addition to the above-mentioned advantages (details will be described in a corresponding embodiment later). Note that examples of the constituent material of the support are not limited thereto, and include, for example, polyethylene terephthalate, polyester, polypropylene, cellophane, polyvinyl chloride, polyolefin, polyvinyl alcohol, polyvinylidene chloride, polystyrene, polyamide, polycarbonate, polyarylate. , Polysulfone, fluororesin, polyacrylonitrile, polyethersulfone, polybutadiene, polyimide and other plastics, paper, synthetic paper, inorganic fiber paper with good thermal conductivity, ceramics, metals, carbon powder and metal powder Examples thereof include plastics having dispersed therein.

Further, in order to expand the applications and improve the characteristics of the thermoreversible recording medium of the first embodiment, in addition to the constitution of the first embodiment, to protect the thermoreversible recording medium as an intermediate layer. From the protective layer, the adhesive layer for improving the fixing strength between the components of the thermoreversible recording medium, the reflective layer or the light absorbing layer (details will be described later), and the enhance layer for improving the display contrast. Depending on the design of the reversible recording medium,
One or more layers selected, and further, a recording layer for recording bar code information, magnetic information, etc. which can be read by an information reading device or the like but cannot be directly recognized by a human (the thermoreversible recording layer of the present invention and Can be arranged in any suitable manner to form a thermoreversible recording medium. These specific examples will be described by the following examples.

Next, twenty-first to twenty-fourth embodiments of the first invention will be described.

The thermoreversible recording medium 61 of the twenty-first embodiment is
As shown in FIG. 4, the support 21 and the reflection layer or the light absorption layer 23 provided on the support 21 as a kind of intermediate layer.
And provided on the reflection layer or the light absorption layer 23, and the first to second
The thermoreversible recording layer 25 of Example 0 and the protective layer 29 which is transparent to visible light and protects the thermoreversible recording layer 25 are provided on the thermoreversible recording layer 25.

Further, in FIG. 4 and each sectional view used in the following description, hatching showing the section is attached only to the reflection layer or the light absorption layer 23 and the thermoreversible recording layer 25, and to the other layers. Hatching is omitted.

The thermoreversible recording medium 61 of the twenty-first embodiment was prepared as follows. The support 21 is made of a polyethylene terephthalate substrate having a predetermined thickness here. On this support 21, a vinyl chloride-vinyl acetate-vinyl acetate copolymer [VYHH manufactured by Union Carbide Co. (UCC)] as a binder and a coating solution in which cadmium red as a color pigment is dissolved in tetrahydrofuran are applied. To do.

When the obtained coating film is dried, the support 2
1 is a layer that mainly reflects red light and absorbs or transmits other light (depending on the wavelength of interest, it can be called a reflection layer, a light absorption layer, or a light transmission layer, or from another perspective, coloring A layer that can also be called a layer, and this layer is referred to as a reflection layer or a light absorption layer.) 23 is formed.

Further, on the reflection layer or the light absorption layer 23 thus produced, the thermoreversible recording layer 25 and the thermoreversible recording layer 25 were prepared by using the coating solutions used in the first to twentieth embodiments of the first invention. The protective layer 29 is formed by the procedure described in the first to twentieth embodiments of the first invention.

A heating means (for example, a thermal head) is brought into contact with the protective layer 29 of the thermoreversible recording medium 61 of the twenty-first embodiment to selectively heat the thermoreversible recording layer 25 to form a transparent portion (printed portion). When formed, it was possible to print in red letters.
Further, as in the first to twentieth examples, repeated recording and erasing experiments were conducted, and it was found that no deterioration in printing was observed. Of course, in the case of the twenty-first embodiment as well, as in the first to twentieth embodiments, the support member 21 is made of a material having good heat conduction, and the support member 21 side is interposed via the support member 21 side. The thermoreversible recording layer 25 may be heated.

As the constituent material of the protective layer 29, for example, the same polyvinyl acetal and UV curable resin as in the first embodiment of the first invention are used. As another example,
As examples of the second to twentieth examples of the first invention and other ultraviolet curable resins, S-COAT UV or the like (P6 to P8) is used.
Polymerizable oligomers or commercially available UV curable resins).

The thickness of the protective layer 29 is the same as that of the thermoreversible recording layer 25.
The film thickness may be a suitable range within which heat from a means for heating (eg, a thermal head) is satisfactorily transferred to the thermoreversible recording layer 25 and a function as a protective layer is obtained. Incidentally, of the surface of the protective layer 29, the thermoreversible recording layer 25
Characters or graphics (for example, the application of the thermoreversible recording medium, for example, characters such as "XX card") may be printed on a portion that does not correspond to the display area.

The reflecting layer or the light absorbing layer 23 is not limited to the layer containing a red pigment. The reflection layer or the light absorption layer 23 may be composed of a pigment other than red, or a layer containing a dye, or a layer containing metal powder such as copper powder or aluminum powder. Further, ink or the like may be applied on the support 21 to form the reflection layer or the light absorption layer 23. Further, plural colors of ink may be printed for the purpose of improving the display contrast. When the reflective layer or the light absorption layer 23 is manufactured,
We decided to use pigments, dyes, and metal powders with good thermal conductivity,
It is also possible to improve the thermal response of the thermoreversible recording medium.

In addition, in the case of the twenty-first embodiment, the support 2
1 can be made of a material having good heat conduction. In the case of this configuration, printing can be performed without disposing a heating means on the viewer's side of the thermoreversible recording medium 61, and in addition to the characters or figures printed on the surface of the protective layer 29, the heat from the heating means is applied. The advantage is that it is less affected. This is considered to be effective in protecting the written characters and figures when drawing characters and figures with water-based or oil-based magic ink on the surface of the protective layer 29.

If necessary, as shown in FIG.
Between the protective layer 29 and the thermoreversible recording layer 25 of the twenty-first embodiment, and / or between the thermoreversible recording layer 25 and the reflective layer or the light absorbing layer 23, both layers 25 as a kind of intermediate layer, You may provide the adhesive layer 31 for improving the adhesive strength of 23 (22nd Example). As an example of the constituent material of the adhesive layer 31,
For example, a polyester resin, a urethane resin, and an epoxy resin can be used, although not limited thereto. In addition,
Reference numeral 62 denotes the thermoreversible recording medium of this embodiment.

Further, as shown in FIG. 6, in the twenty-third embodiment, as another example of the intermediate layer, a dedicated layer for printing characters and graphics, that is, a printing layer is provided at an appropriate position of the thermoreversible recording medium. Can be provided. Here, the thermoreversible recording medium 6 having a printing layer 33 between the adhesive layer 31 and the protective layer 29.
3 can be obtained.

Further, as shown in FIG. 7, in the twenty-fourth embodiment, a thermoreversible recording medium 64 having a printing layer 33 between the reflection layer or the light absorption layer 23 and the adhesive layer 31 is shown. Of course, the provision of the adhesive layer and the printing layer is not limited to the twenty-third and twenty-fourth embodiments, but can be applied to each of the other embodiments.

Next, a twenty-fifth embodiment and a twenty-sixth embodiment of the first invention.
Examples will be described.

As shown in FIG. 8, a thermoreversible recording medium 71 of the twenty-fifth embodiment has a thermoreversible recording layer in addition to the structure of the thermoreversible recording medium 61 of the twenty-second embodiment shown in FIG. 25
An enhancement layer 35 for improving display contrast is provided as a kind of intermediate layer between the reflection layer and the light absorption layer 23. The enhance layer 35 enhances the display contrast by increasing the contrast between the transparent portion and the cloudy portion formed on the thermoreversible recording layer 25.

As an example of the constituent material of the enhancement layer 35,
For example, but not limited to, polyester, polyethylene, polypropylene, cellophane, polyvinyl chloride,
Plastics such as polyolefin, polyvinyl alcohol, polyvinylidene chloride, polystyrene, polyamide, polycarbonate, polyarylate, polysulfone, fluororesin, polyacrylonitrile, polyether sulfone, polybutadiene, polyimide, and UV curable resin, and SiO ₂ , TiO ₂ , Al ₂ O _{3 and} other inorganic substances.

As shown in FIG. 9, as the twenty-sixth embodiment, the enhancement layer may be composed of the air layer 35a. In the twenty-sixth embodiment, an adhesive layer 31 is provided in a part between the reflective layer or light absorbing layer 23 and the thermoreversible recording layer 25, and the reflective layer or light absorbing layer 23 and the thermoreversible recording layer 25 are provided. An air layer 35a is formed in a portion between the two, where the adhesive layer 31 is not provided, thereby forming an enhancement layer.

Further, also in the twenty-fifth and twenty-sixth embodiments, the support 21 can be made of a material having good heat conduction. However, it is considered that the embodiment in which the enhancement layer is composed of the air layer 35a is not so effective because the degree of heat transfer to the thermoreversible recording layer 25 is reduced by the air layer 35a.

Next, the 27th embodiment and the 28th embodiment of the first invention.
Examples will be described.

As shown in FIGS. 10 and 11, the thermoreversible recording layer 25 of the 27th and 28th embodiments records visible characters and figures. However, if the thermoreversible recording media 81 and 82 are capable of storing and rewriting coded information as well, it records composite information of directly visible thermal recording and coded recording. And a thermoreversible recording medium that can be used is obtained, which is preferable.

If such a thermoreversible recording medium can be constructed, it can be used, for example, to construct a prepaid card, and code information indicating a balance or the like can be recorded on the thermoreversible recording layer. Furthermore, this balance information is read by an external reading device, a new balance is calculated by the external control device from this information and the amount of money that has just been used, this new balance is displayed on the thermoreversible recording layer, and It is preferable because the reversible recording medium can be renewed and recorded, and the application of the thermoreversible recording medium is widened.

The twenty-seventh and twenty-eighth embodiments, which are examples of the thermoreversible recording medium having such a recording layer, will be described below.

Where the recording layer capable of recording / rewriting the code information is provided in the thermoreversible recording medium can be arbitrarily determined according to the design of the thermoreversible recording medium. In the 27th embodiment, a recording layer 37 is provided on the back surface of the support 21 of the thermoreversible recording medium 61 described with reference to FIG. 4 in the 21st embodiment, as shown in FIG. In order to protect the recording layer 37, a second protective layer 39 covering the recording layer 37 was provided.

Further, as shown in FIG. 11, as a 28th embodiment, the thermoreversible recording layer 25 and the reflecting layer or the light absorbing layer 23 are used.
Of course, a configuration including the enhancement layer 35 between and may be used. The constituent material of the second protective layer 39 can be selected from various materials that can form the protective layer 29, for example.

The recording format on the recording layer 37 is not limited to this, but it is a magnetic recording method, an optical recording method, an electrical recording method, or a heat recording method for recording invisible code information. Can be one or more of The recording layer 37 may be composed of, for example, the IC card itself.

Also in the twenty-seventh and twenty-eighth embodiments, the support 21 may be made of a material having good heat conduction.

Next, a twenty-ninth embodiment and a thirtieth embodiment of the first invention.
Examples will be described.

As shown in FIG. 12, the thermoreversible recording medium 91 of the twenty-ninth embodiment has a thermoreversible recording on a transparent support (hereinafter, simply referred to as support) 41 made of a material transparent to visible light. The layer 25 and the protective layer 29 are provided in this order, and the support 4
1 has a reflective layer or a light absorbing layer 23 on the back surface thereof. In this structure, a support 41 is used as a support, and the support 41 is disposed between the thermoreversible recording layer 25 and the reflection layer or the light absorption layer 23. The support 41 itself acts like an enhancement layer. Of course, like the thermoreversible recording medium 92 of the thirtieth embodiment shown in FIG. 13, in addition to the configuration of the twenty-ninth embodiment of FIG. 12, an original space between the support 41 and the reflection layer or the light absorption layer 23 is provided. The enhancement layer 35 (or the air layer 35a may be used) may be provided.

Examples of the constituent material of the support 41 are transparent plastics such as polyester, polyethylene,
Examples thereof include polypropylene, cellophane, polyvinyl chloride, polyolefin, polyvinyl alcohol, polyvinylidene chloride, polystyrene, polyamide, polycarbonate, polyarylate, polysulfone, fluororesin, polyacrylonitrile, polyether sulfone and polybutadiene.

Also in the case of the 29th and 30th embodiments, for example, in the configuration of FIG. 12 or 13, under the reflecting layer or the light absorbing layer 23, as shown in FIG. 10 and FIG.
The recording layer 37 and the second protective layer 39 may be provided.

Next, the 31st to 33rd embodiments of the first invention will be described.

FIG. 14 is a sectional view of a thermoreversible recording medium showing the 31st embodiment.

In this embodiment, the reflective layer or the light absorbing layer is not provided, and heating is performed from the transparent protective layer 29 side to print on the thermoreversible recording layer 25. In FIG. 14, reference numeral 41 is a support, and 101 is a thermoreversible recording medium.

FIG. 15 shows a thirty-second embodiment, in which the support 41 is made of a material having good thermal conductivity and is transparent, and the support 41 is heated to print on the thermoreversible recording layer 25. Here is an example. Similar to the 31st embodiment, this embodiment also shows an example in which light is incident from the support 41 of the thermoreversible recording medium. Of course, the light may be incident from the protective film 29 side.

As the 33rd embodiment, as shown in FIG. 16, the recording layer 37 is provided. That is, FIG. 16 shows an example in which the recording layer 37 and the second protective layer 39 for protecting the recording layer 37 are provided in a portion of the back surface of the support 41 that does not interfere with light incidence. ing. Of course, also in this embodiment, the support 41 may be made of a material having good thermal conductivity, and the thermoreversible recording layer 25 may be heated via the support 41. In addition, 29 is a protective film, 1
Reference numeral 03 is a thermoreversible recording medium.

Next, the 34th to 41st embodiments of the first invention will be described with reference to FIGS. 17 to 24. In these examples, 111 to 118 are thermoreversible recording media.

In the thermoreversible recording media of the thirty-first to thirty-third embodiments, the data printed on the media was viewed mainly from the protective film 29 side. However, printing is performed from the side of the support body 41 by forming the support body 41 itself with the transparent support body 41 and providing the reflection layer or the light absorption layer 23 between the thermoreversible recording layer 25 and the protective layer 29. You may want to look at the data. Some examples will be described below. However, in the 34th to 39th embodiments, the protective layer 29 may not have transparency.

First, FIG. 17 shows a thirty-fourth embodiment which is an example in which a thermoreversible recording layer 25, a reflecting layer or a light absorbing layer 23 and a protective layer 29 are provided in this order on a transparent support 41. Exactly, the thermoreversible recording medium 61 of the twenty-first embodiment shown in FIG.
Corresponds to an example in which the display is changed on the support side.

Further, FIG. 18 shows a 35th embodiment, and an adhesive layer 31, a thermoreversible recording layer 25, an adhesive layer 31, a reflecting layer or a light absorbing layer 23 and a protective layer 29 are arranged in this order on a transparent support 41. This is an example provided. This corresponds to an example in which the thermoreversible recording medium 62 of the twenty-second embodiment shown in FIG. 5 is changed so that the display can be seen on the support side. Furthermore, FIG. 19 shows a printing layer 33, an adhesive layer 31, a thermoreversible recording layer 25, an adhesive layer 31, a reflecting layer or a light absorbing layer 2 on a support 41 in a 36th embodiment.
3 and the protective layer 29 are provided in this order. This corresponds to an example in which the thermoreversible recording medium 64 shown in FIG. 6 is changed so that the display can be seen on the support side.

FIG. 20 shows a transparent support member 41 according to the 37th embodiment.
On top, the adhesive layer 31, the thermoreversible recording layer 25, the adhesive layer 31,
This is an example in which the print layer 33, the reflection layer or the light absorption layer 23, and the protection layer 29 are provided in this order. This corresponds to an example in which the thermoreversible recording medium 63 shown in FIG. 7 is changed so that the display can be seen on the support side.

FIG. 21 shows a transparent support member 41 according to the 38th embodiment.
This is an example in which a thermoreversible recording layer 25, an enhancement layer 35, a reflection layer or a light absorption layer 23, and a protective layer 29 are provided in this order on the above. This corresponds to an example in which the thermoreversible recording medium 71 shown in FIG. 8 is changed so that the display can be seen on the support side.

FIG. 22 shows a 39th embodiment, which is a transparent support 41.
This is an example in which a thermoreversible recording layer 25, an enhancement layer composed of an air layer 35a, a reflection layer or a light absorption layer 23, and a protective layer 29 are provided in this order on top. This corresponds to an example in which the thermoreversible recording medium 72 shown in FIG. 9 is changed so that the display can be seen on the support side.

FIG. 23 shows a transparent support 41 according to the 40th embodiment.
A thermoreversible recording layer 25, a reflective layer or a light absorbing layer 23,
This is an example in which the recording layer 37 and the second protective layer 39 are provided in this order. The thermoreversible recording medium 81 shown in FIG.
Corresponds to an example in which the display is changed on the support side.

FIG. 24 shows a transparent support member 41 according to a forty-first embodiment.
On top, a thermoreversible recording layer 25, an enhancement layer 35 (may be an air layer), a reflection layer or a light absorption layer 23, a recording layer 3
7 and the second protective layer 39 are provided in this order. This corresponds to an example in which the thermoreversible recording medium 82 shown in FIG. 11 is changed so that the display can be seen on the support side.

Next, the 42nd embodiment will be explained.

In the twenty-first to forty-first embodiments, as a support used when light is incident from the support side, a structure in which light enters the main surface of the support at a right angle is mainly considered. However, the support itself may have the property of changing the direction of light incident on the support. This way
This is because, for example, it is possible to reduce the design constraint of the thermoreversible recording medium due to the positional relationship between the thermoreversible recording layer and the light source.

This will be described below.

FIG. 25 is a diagram showing a forty-second embodiment of the first invention.

In this embodiment, the end face 51a of the plate member 51 is
When light is incident from the plate-shaped member 51, the light is bent at a right angle in the plate-shaped member 51 and emitted from the main surface of the plate-shaped member 51 (also referred to as an edge light system). An example is shown in which the body 51 is used as a support for the thermoreversible recording medium 121. Specific examples of such a plate-like body 51 include acrylite (trade name) provided by Mitsubishi Rayon Co., Ltd., which uses an acrylic resin. Of course, the structure to which the idea of the 42nd embodiment can be applied is not limited to that of FIG. 25, but can be widely applied to the structures of the 21st to 41st embodiments described above.

[B] Next, writing of information to the thermoreversible recording medium will be described.

FIG. 26 is an explanatory view of writing information to the thermoreversible recording medium, and shows an example of a device for writing information to the thermoreversible recording medium 100 and the thermoreversible recording medium 100.
Shows the relationship with.

In FIG. 26, 200a to 200c are
Each is a recording device with a different function, and
00 is information for recording (for example, “A” “I” “U”)
"E" and "O") are stored and the recording devices 200a-2
00c is a control device for controlling 00c.

Here, the recording apparatus 200a comprises an information printing thermal head 201 and an information erasing heating block (or heating roll) 202. The recording device 200b includes, in addition to the configuration of the recording device 200a, an optical reading device 203 for reading information on the recording layer, particularly information recorded by an optical recording method. The recording device 200c is
In addition to the configuration of the recording device 200a, a reading head 204 for reading information on the recording layer, particularly coded information,
Recording head 205 for writing coded information
Equipped with.

(1) In the case where the thermoreversible recording medium 100 has, for example, the above-mentioned recording layer-free structure,
A user uses the thermoreversible recording medium 100 as a recording device 200.
Insert into a. The control device 300 uses the thermoreversible recording medium 10
Detecting that 0 has been inserted, print information (for example, "A""I""U""E""O")
A command is sent to the recording device 200a.

Upon receipt of this command, the recording apparatus 200a uses the information printing thermal head 201 to directly or protective layer or support the thermoreversible recording layer of the thermoreversible recording medium 100 for a predetermined time with a predetermined power. Selectively heat through the body. When the thermoreversible recording medium 100 has the thermal history characteristics shown in FIG. 2, the portion of the thermoreversible recording medium 100 on which "a", "i", "u", "e", "o" is to be printed,
After heating to 120 to 200 ° C., rapid cooling to room temperature causes the relevant portion to become transparent, and the other portions remain cloudy. The above printing can be performed under the condition that the printing power is 0.1 W / dots and the printing time is 1 msec. Of course, this printing condition is an example.

After the printing is completed, the user takes out the thermoreversible recording medium 100 from the recording device 200a. The thermoreversible recording medium 100 taken out is "a""i""u"
The printed parts of "E" and "O" were fixed in a transparent state. Furthermore, the contrast indicated by the transmittance ratio between the transparent portion and the cloudy portion is, for example, 20 (wavelength 550 nm
It is said by the transmittance for light). As a result, the user can visually check the information recorded in the thermoreversible recording medium 100 as "A", "I", "U", "E", "O". In addition, this information "A""I""U""E"
“O” is retained until the next use of the thermoreversible recording medium medium.

[0166] The user is required to use the thermoreversible recording medium 100.
When erasing the previously recorded information, the thermoreversible recording medium 100 is inserted into the recording device 200a. Recording device 20
In the case where the thermoreversible recording medium 100 has the heat history characteristic of FIG. 2, 0a heats the thermoreversible recording medium 100 in the temperature range of 90 to 200 ° C. by the heating roll 202,
Slowly cool to room temperature. The thermoreversible recording medium 100 becomes cloudy and the previous record is erased. Further, when new information is recorded on the thermoreversible recording medium 100 that has been erased,
Processing is performed according to the above printing procedure.

(2) If the thermoreversible recording medium 100 has, for example, the above-mentioned recording layer, and particularly a recording layer for recording information by an optical recording method, the user can use this thermoreversible recording medium. The recording medium 100 is inserted into the recording device 200b. Then, the recording device 200b causes the optical reading device 203 to read the optical information recorded in the recording layer and sends it to the control device 300. This optical information
For example, in the case of the recognition information of the owner of the thermoreversible recording medium 100, the thermoreversible recording medium 10 is controlled by the control device 300.
It is possible to confirm the correctness of 0 users. Writing information to the thermoreversible recording layer and erasing information from the thermoreversible recording layer
It can be performed by the same means as above.

(3) The thermoreversible recording medium 100 has, for example, the above-mentioned recording layer, for example, a recording layer capable of recording coded information and changing the information, such as a magnetic recording layer. In some cases, the user inserts the thermoreversible recording medium 100 into the recording device 200c. Then, the recording device 200c reads the coded information stored in the recording layer of the thermoreversible recording medium 100 with the read head 204 and sends it to the control device 300. Here, for example, the coded information can be, for example, balance information when the thermoreversible recording medium 100 is considered as a prepaid card, for example.

The control device 300 calculates a new balance from this balance information and the amount of money consumed by the user, records the new balance on the recording layer of the thermoreversible recording medium 100, and heats it. Commands for displaying as visual information on the reversible recording layer are sent to the recording device 200c, respectively. Recording device 2
00c writes new balance information to the recording layer by the recording head 205, and at the same time, the information printing thermal head 20
2, the thermoreversible recording layer 25 is formed.

Among the thermoreversible recording media described above,
A type in which the display is viewed from one side of the thermoreversible recording medium, and a type in which heat printing is performed from the other side of the thermoreversible recording medium [for example, the thermoreversible type shown in FIGS. 15 and 18] In the case of the recording medium], it is necessary to adjust the print signal of the information printing thermal head 201 in the control device 300 so that the characters can be seen normally on the visual side.

[C] The second invention (the thermoreversible recording apparatus) will be described.

Next, an example of a thermoreversible recording apparatus (hereinafter abbreviated as “recording apparatus”) will be described.

(1) The first embodiment of the second invention will be described.

FIG. 27 is a block diagram of the first embodiment of the second invention.

This recording apparatus is an entire erasing tool provided with a frame 403 and a heating element provided on the frame 403 for erasing the entire surface of the thermoreversible recording layer (see FIG. 1 etc.) of the thermoreversible recording medium. 401 and the thermoreversible recording medium 500 provided so as to be in contact with the entire eraser 401.
A writing tool 402 for forming a print portion (image) on the thermoreversible recording medium 500, and a local erasing tool 40 for erasing a part of the image formed on the thermoreversible recording medium 500.
4 and a temperature control unit 405 for controlling the temperature of the total erasing tool 401.

Here, the frame 403 can be made of a suitable material such as metal or resin according to the design of the recording apparatus. Further, the overall erasing tool 401 can be composed of, for example, a panel heater. The entire eraser 401 is a thermoreversible recording medium 50.
It is assumed that the temperature according to the characteristic of 0 (see, for example, FIG. 2) can be applied. The temperature control unit 405 that enables this can be configured by a conventionally known one.

Further, as the thermoreversible recording medium 500, the one described in the 21st to 42nd embodiments is used. Further, the writing instrument 402 includes a cylindrical main body portion, a head portion provided at a tip portion thereof, a heat generating portion built in the main body portion for heating the head portion, a power source for the heat generating portion, and a power switch ( (Not shown). Writing instrument 40
The second head portion is preferably made of a material having good thermal conductivity, for example, a metal such as copper or ceramics.

Further, the shape of the head portion is preferably tapered, but regarding the thickness thereof,
It is good to decide considering the size of the characters you want to draw.
Further, the heat generating portion can be composed of a resistance heating element such as a nichrome heater or a ceramic heater. The power source for the heat generating portion may be either a DC power source (including batteries) or an AC power source.

According to this recording apparatus, the total erasing tool 401
2 is operated according to Condition 13 in the thermal history of FIG. 2, the recording layer of the thermoreversible recording medium 500 becomes cloudy. When the writing tool 402 in the on state is brought into contact with the cloudy screen, the recording layer becomes transparent at the portion where the cloudy screen is in contact, and the color of the colored support becomes transparent, and in this case, the red printing portion. Can be seen. As a result, an image composed of a white background portion and a red printing portion can be formed on the display body. Also, if you want to erase only a part of the image, local eraser 4
The image can be erased by touching 04.

(2) Next, a second embodiment of the second invention will be described.

FIG. 28 is an explanatory diagram of the second embodiment of the second invention.

The recording apparatus of the second embodiment is an example of an apparatus in which the thermoreversible recording medium of the first invention is applied to the display surface of a display. Specifically, the thermoreversible recording medium of the second invention, which has a band shape and a closed loop shape (hereinafter, referred to as a loop-shaped thermoreversible recording medium 500a).
And a first platen roll 60 for holding and orbiting the loop-shaped thermoreversible recording medium 500a when necessary.
First and second platen rolls 602, a recording device 604 for recording information on the loop-shaped thermoreversible recording medium 500a and erasing information on the loop-shaped thermoreversible recording medium 500a, and first and second Platen roll 601,
Control device 60 for controlling running / stopping and running speed of 602, and recording and erasing of the information by recording device 604
5 is a device including.

Here, the recording device 604 is, for example, as shown in FIG.
The recording device 200a described with reference to FIG.
Further, the control device 605 can be configured by any suitable device using known print control technology and transport control technology.

The recording apparatus according to the second embodiment of the second invention can be used as, for example, an electronic bulletin board when performing display while moving the loop-shaped thermoreversible recording medium 500a. If the loop-shaped thermoreversible recording medium 500a is stopped at a proper time, it can be used as a bulletin board for predetermined information.

The present invention is not limited to the above embodiments, and various modifications can be made based on the spirit of the present invention, which are not excluded from the scope of the present invention.

[0186]

As described in detail above, according to the present invention, the following effects can be achieved.

[I] According to the thermoreversible recording medium of the first invention of the present invention, (1) a thermoreversible recording medium that is less likely to cause reduction in display contrast when recording and erasing are repeated than in the past can get.

(2) It is possible to obtain a medium having a high surface hardness, a high thermal strength, and a strong mechanical shock from the outside. For this reason,
The restriction on the temperature control of thermal means such as a thermal head can be relaxed as compared with the conventional case.

(3) Since the warp is reduced, when recording and erasing are repeatedly performed by the recording device and the erasing device, the warp does not cause the device to be caught or inserted into the device.

(4) It is not necessary to heat the thermoreversible recording medium at the time of preparation (because curing is caused by irradiation of ultraviolet rays), and a thermoreversible recording medium in which deterioration of the recording layer due to heating is small can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of a thermoreversible recording medium showing a first embodiment of the first invention.

FIG. 2 is a diagram showing characteristics of the thermoreversible recording material of the first invention.

FIG. 3 is a diagram showing a method for measuring the warp of the thermoreversible recording medium of the first invention.

FIG. 4 is a sectional view of a thermoreversible recording medium showing a 21st embodiment of the first invention.

FIG. 5 is a sectional view of a thermoreversible recording medium showing a 22nd embodiment of the first invention.

FIG. 6 is a sectional view of a thermoreversible recording medium showing a 23rd embodiment of the first invention.

FIG. 7 is a sectional view of a thermoreversible recording medium showing a twenty-fourth embodiment of the first invention.

FIG. 8 is a sectional view of a thermoreversible recording medium showing a 25th embodiment of the first invention.

FIG. 9 is a sectional view of a thermoreversible recording medium showing a 26th embodiment of the first invention.

FIG. 10 is a sectional view of a thermoreversible recording medium showing a 27th embodiment of the first invention.

FIG. 11 is a sectional view of a thermoreversible recording medium showing a 28th embodiment of the first invention.

FIG. 12 is a sectional view of a thermoreversible recording medium showing a 29th embodiment of the first invention.

FIG. 13 is a sectional view of a thermoreversible recording medium showing a thirtieth embodiment of the first invention.

FIG. 14 is a sectional view of a thermoreversible recording medium showing a 31st embodiment of the first invention.

FIG. 15 is a sectional view of a thermoreversible recording medium showing a 32nd embodiment of the first invention.

FIG. 16 is a sectional view of a thermoreversible recording medium showing a 33rd embodiment of the first invention.

FIG. 17 is a sectional view of a thermoreversible recording medium showing a 34th embodiment of the first invention.

FIG. 18 is a sectional view of a thermoreversible recording medium showing a thirty-fifth embodiment of the first invention.

FIG. 19 is a sectional view of a thermoreversible recording medium showing a 36th embodiment of the first invention.

FIG. 20 is a sectional view of a thermoreversible recording medium showing a 37th embodiment of the first invention.

FIG. 21 is a sectional view of a thermoreversible recording medium showing a 38th embodiment of the first invention.

FIG. 22 is a sectional view of a thermoreversible recording medium showing a 39th embodiment of the first invention.

FIG. 23 is a sectional view of a thermoreversible recording medium showing a 40th embodiment of the first invention.

FIG. 24 is a sectional view of a thermoreversible recording medium showing a 41st embodiment of the first invention.

FIG. 25 is a sectional view of a thermoreversible recording medium showing a 42nd embodiment of the first invention.

FIG. 26 is a diagram showing an example of use of the thermoreversible recording medium of the first invention.

FIG. 27 is a structural diagram of a recording apparatus using a thermoreversible recording medium showing a first embodiment of the second invention.

FIG. 28 is a configuration diagram of a recording apparatus using a thermoreversible recording medium showing a second embodiment of the second invention.

[Explanation of symbols]

15 Surface plate 20, 61, 62, 63, 64, 71, 72, 81, 8
2, 91, 92, 100, 101, 102, 103, 1
11 to 118, 121,500 Thermoreversible recording medium 21 Support 23 Reflective layer or light absorbing layer 25 Thermoreversible recording layer 29 Protective layer 31 Adhesive layer 33 Printing layer 35 Enhance layer 35a Air layer (enhance layer) 37 Recording layer 39 2nd protective layer 41 Transparent support body 51 Plate-like body 51a End surface 200a-200c, 604,605 of plate-like body Recording device 201 Thermal head 202 for information printing Heating block (or heating roll) for information erasing 203 Optical reading Device 204 Read head 205 for reading information Recording head 300, 605 for writing coded information Controller 403 Frame 401 Whole eraser 402 Writing implement 404 Local eraser 405 Temperature controller 500a Loop thermoreversible recording medium 601 First platen roll 602 Second platen roll

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Fumio Nakagawa 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd. (72) Hiroyo Kato 1-7-12 Toranomon, Minato-ku, Tokyo No. Oki Electric Industry Co., Ltd. (56) Reference JP-A-6-64318 (JP, A) JP-A-6-48032 (JP, A) JP-A-4-363294 (JP, A) JP-A-5 -246143 (JP, A) JP-A-6-8626 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B41M 5/36 B41M 5/28-5/34

Claims (10)

(57) [Claims] 1. A thermoreversible recording layer composed of a thermoreversible recording material which contains at least a matrix material and an organic low molecule and whose transparency changes according to thermal history, and a support for supporting the thermoreversible recording layer. In the thermoreversible recording medium having a protective layer on the side opposite to the support directly or via an intermediate layer, polyvinyl acetal and an ultraviolet curable resin (provided that the curable agent is cured) are used as the protective layer. A thermoreversible recording medium characterized by being used. 2. The thermoreversible recording medium according to claim 1, wherein the compounding ratio of the polyvinyl acetal used as the protective layer and an ultraviolet curable resin (provided that it is cured with a curing agent) is 100 in the case of polyvinyl acetal: ultraviolet curable resin.
A thermoreversible recording medium, characterized in that it is 0: 1 to 1: 2. 3. The thermoreversible recording medium according to claim 1, wherein the thermoreversible recording material uses polyvinyl butyral as a matrix material, and is selected from a group of saturated carboxylic acids and derivatives of the saturated carboxylic acids as organic low molecules. A thermoreversible recording medium comprising at least one selected. 4. The thermoreversible recording medium according to claim 1, wherein the thermoreversible recording material uses a polyvinyl acetal or a matrix material containing polyvinyl acetal as a main component as a matrix material, and a saturated carbon as an organic low molecule. A thermoreversible recording medium comprising an acid and at least one selected from the group of derivatives of the saturated carboxylic acid. 5. The thermoreversible recording medium according to claim 4, wherein an epoxy resin, a phenol compound, an epoxy compound, an aldehyde compound, an isocyanic acid compound, is added to the polyvinyl acetal contained in the thermoreversible recording layer . Epoxy resin (provided by curing agent), UV curable resin (provided by curing agent) , or organosiloxane (provided by crosslinking)
A thermoreversible recording medium characterized by using. 6. The thermoreversible recording medium according to claim 1, wherein at least one of the support and the protective layer is made of a material having transparency to visible light. . 7. The thermoreversible recording medium according to claim 1, wherein when the intermediate layer is used, the intermediate layer is selected from at least a reflection layer, a light absorption layer, an enhancement layer and a printing layer.
A thermoreversible recording medium comprising one or more layers selected according to the direction of light incident on the thermoreversible recording medium and the viewing direction of the recording formed on the thermoreversible recording medium. 8. The thermoreversible recording medium according to claim 1, wherein the support is made of a material having transparency to visible light, and the support is reflected on the side opposite to the thermoreversible recording layer. A thermoreversible recording medium comprising a layer or a light absorbing layer. 9. The heat-reversible recording medium according to claim 1, wherein the support has a property of changing a traveling direction of light incident on the support. Reversible recording medium. 10. The thermoreversible recording medium according to claim 1, which is separate from the thermoreversible recording layer.
A thermoreversible recording medium having a recording layer.