JP2007062295A - Reversible thermosensitive recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reversible thermosensitive recording medium in which the stability of coloring density and coloring image is high and erasability is good. <P>SOLUTION: In the reversible thermosensitive recording medium in which a reversible thermosensitive recording layer containing a reversible thermosensitive composition which can form a relatively colored state and discolored state by a difference between a heating temperature and/or cooling rate after heating, using at least electron-donative coloration nature compound and electron-receptive compound on a supporter and furthermore a protection layer as needed or a protection layer one by one through an intermediate layer; a compound expressed with a formula [1]: A-SO2NHN=CH-B as a coloring discharge controlling agent in the reversible thermosensitive recording layer is made to contain. In the formula [1], A is a chain hydrocarbon group having a carbon number of 6-24 or an aromatic group which may have a substituent, and B is an aromatic annulus group or a complex annulus group which may have a substituent. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  This case has a reversible thermosensitive recording layer using a reversible thermosensitive coloring composition utilizing a coloring reaction between an electron-donating color-forming compound and an electron-accepting compound, and a color image by controlling thermal energy. A reversible thermosensitive recording medium capable of forming and erasing, a member having an information storage section having the reversible thermosensitive recording layer as a reversible display section, a reversible thermosensitive recording label having the reversible thermosensitive recording layer, and images The present invention relates to an image processing method for forming and erasing image.

  2. Description of the Related Art Conventionally, heat-sensitive recording media using a color developing reaction between an electron donating color developing compound (hereinafter also referred to as a color former or a leuco dye) and an electron accepting compound (hereinafter also referred to as a developer) are widely known. With the progress of OA, it is widely used as output paper for facsimiles, word processors, scientific measuring instruments, etc., and recently as magnetic thermal cards such as prepaid cards and point cards, but from the viewpoint of environmental issues and recycling. Therefore, development of a reversible thermosensitive recording medium that can be rewritten any number of times is desired, and the present inventors have disclosed an organic compound having a long-chain aliphatic hydrocarbon group as a developer in Japanese Patent No. 2981558 (Patent Document 1). By using phosphoric acid compounds, aliphatic carboxylic acid compounds or phenolic compounds, and combining these with leuco dyes that are color formers Coloring and erasing can be easily performed under heating and cooling conditions, the coloring and erasing states can be kept stable at room temperature, and reversible feeling that can repeat coloring and erasing A thermochromic composition and a reversible thermosensitive recording medium using the same for a recording layer have been proposed. Thereafter, the use of a specific structure for a phenol compound having a long-chain aliphatic hydrocarbon group (for example, Japanese Patent No. 3380277 ... Patent Literature 2, Patent No. 3555776 ... Patent Literature 3) was proposed. Yes.

  A reversible thermosensitive recording medium produced using these materials can be colored by a thermal head, erased by a hot stamp, etc., and can be repeatedly colored / decolored. However, in these recording media, the color density is high, and those with a stable color image have poor erasability, and the temperature range where the color is sufficiently erased is high or the image density is low when the color erasure temperature range is low. Are low, and the stability of the image area is poor.

  In order to solve such a problem, the present inventors have disclosed a coloring / decoloring control agent as described in JP-A-11-70731 (Patent Document 4), JP-A-2003-94823 (Patent Document 5) and the like. As described above, it has been proposed to use a specific compound having a chain hydrocarbon group in combination, but the stability of the color image and the erasability are not satisfactory.

Japanese Patent No. 2981558 Japanese Patent No. 3380277 Japanese Patent No. 3557076 Japanese Patent Laid-Open No. 11-70731 JP 2003-94823 A

An object of the present invention is to provide a reversible thermosensitive recording medium having a reversible thermosensitive recording layer in which the color density of the formed image and the stability of the color image are high and the erasability is good.
Another object of the present invention is to provide a member having an information storage unit having the reversible thermosensitive recording layer as a reversible display unit, and a reversible thermosensitive recording label having the reversible thermosensitive recording layer.
Another object of the present invention is to provide an image processing method for forming and erasing an image on the reversible thermosensitive recording medium, the member having an information storage member, and the reversible thermosensitive recording label.

As a result of intensive studies to solve the above problems, the present inventors have reduced the storage stability of the colored state against heat by using a compound having a specific structure (a compound having a sulfonyl hydrazone structure). The present inventors have found that the color erasability can be improved without causing deterioration and that good high speed erasing characteristics can be obtained.
Although the detailed reason is not clear, the reason why the preservability against heat does not decrease is that the compound having the sulfonyl hydrazone structure is mainly used as a dye and an electron accepting compound as an electron donating color developing compound in a colored state. This is thought to be because the color developing structure at a high temperature is stably maintained in order to enter into the color developing aggregate structure constituted by the above developer and to create a more stable structure. Further, in the decoloring process, it is considered that the unerased residue at the time of decoloring is reduced in order to promote crystallization to the decolored state because it takes a cohesive structure stronger than the cohesive force of only the developers.

That is, the said subject is solved by following (1)-(13) of this invention.
(1) “At least an electron-donating color-forming compound and an electron-accepting compound are used on a support, and a relatively colored state and a decolored state are caused by a difference in heating temperature and / or cooling rate after heating. In a reversible thermosensitive recording medium comprising a reversible thermosensitive recording layer containing a reversible thermosensitive composition that can be formed, the color reversible thermosensitive recording layer is represented by the following general formula [1] A reversible thermosensitive recording medium comprising a compound.

（式［１］中、Ａは炭素数６〜２４の鎖状の炭化水素基、または置換基を有していてもよい芳香環基を示し、Ｂは置換基を有していてもよい芳香環基もしくは複素環基を示す。）」；
（２）「前記電子受容性化合物が、下記一般式［２］で表わされるフェノール化合物である化合物を含有することを特徴とする前記（１）に記載の可逆性感熱記録媒体。

(In the formula [1], A represents a chain hydrocarbon group having 6 to 24 carbon atoms, or an aromatic ring group that may have a substituent, and B represents an aromatic that may have a substituent. A cyclic group or a heterocyclic group));
(2) The reversible thermosensitive recording medium according to (1) above, wherein the electron-accepting compound contains a compound represented by the following general formula [2].

（式［２］中、ｎは１〜３の整数を示し、ＸはＮ原子またはＯ原子を含む２価の基を表わす。また、Ｒ_１は置換基を有していてもよい炭素数２以上の２価の脂肪族炭化水素基を表わし、Ｒ_２は置換基を有していてもよい炭素数１〜３０の１価の脂肪族炭化水素基を表わす。）」；
（３）「前記電子受容性化合物が、前記一般式［２］中、Ｘが尿素基であるフェノール化合物であることを特徴とする前記（２）に記載の可逆性感熱記録媒体」；
（４）「前記可逆性感熱記録層が架橋状態にある樹脂を含有することを特徴とする前記（１）乃至（３）のいずれかに記載の可逆性感熱記録媒体」；
（５）「前記可逆性感熱記録層の上に、直接、又は中間層を介して保護層を設けたことを特徴とする前記（１）乃至（４）のいずれかに記載の可逆性感熱記録媒体」；
（６）「前記支持体と前記可逆性感熱記録層の間に断熱層を有することを特徴とする前記（１）乃至（５）のいずれかに記載の可逆性感熱記録媒体」；
（７）「情報記憶部と可逆表示部を有し、該可逆表示部が少なくとも前記（１）乃至（６）のいずれかに記載の可逆性感熱記録媒体を構成する可逆性感熱記録層からなるものであることを特徴とする情報記録部を有する部材」；
（８）「前記情報記憶部を有する部材が、カード、ディスク、ディスクカートリッジ又はテープカセットのいずれかであることを特徴とする前記（７）に記載の情報記憶部を有する部材」；
（９）「前記（１）乃至（６）のいずれかに記載の可逆性感熱記録媒体を構成する支持体において、可逆性感熱記録層を設けた面とは反対の面に、接着剤層又は粘着剤層を設けたことを特徴とする可逆性感熱記録ラベル」；
（１０）「前記（９）に記載の可逆性感熱記録ラベルを用いて可逆表示部が設けられているものであることを特徴とする前記（７）又は（８）に記載の情報記憶部を有する部材」；
（１１）「前記（１）乃至（６）のいずれかに記載の可逆性感熱記録媒体、又は前記（９）に記載の可逆性感熱記録ラベル、或いは前記（７）、（８）、（１０）のいずれかに記載の情報記憶部を有する部材において、可逆性感熱記録層を加熱することにより画像の形成及び／又は消去を行なうことを特徴とする画像処理方法」；
（１２）「サーマルヘッドを用いて画像を形成することを特徴とする前記（１１）に記載の画像処理方法」；
（１３）「サーマルヘッド又はセラミックヒータを用いて画像を消去することを特徴とする前記（１１）に記載の画像処理方法」。

(In the formula [2], n represents an integer of 1 to 3, X represents a divalent group containing an N atom or an O atom, and R ₁ has 2 carbon atoms which may have a substituent. The above divalent aliphatic hydrocarbon group is represented, and R ₂ represents a monovalent aliphatic hydrocarbon group having 1 to 30 carbon atoms which may have a substituent.
(3) “The reversible thermosensitive recording medium according to (2) above, wherein the electron-accepting compound is a phenol compound in which X is a urea group in the general formula [2]”;
(4) “The reversible thermosensitive recording medium according to any one of (1) to (3) above, wherein the reversible thermosensitive recording layer contains a resin in a crosslinked state”;
(5) The reversible thermosensitive recording according to any one of (1) to (4), wherein a protective layer is provided directly or via an intermediate layer on the reversible thermosensitive recording layer. Medium ";
(6) “The reversible thermosensitive recording medium according to any one of (1) to (5) above, which has a heat insulating layer between the support and the reversible thermosensitive recording layer”;
(7) “It has an information storage unit and a reversible display unit, and the reversible display unit comprises at least a reversible thermosensitive recording layer constituting the reversible thermosensitive recording medium according to any one of (1) to (6). A member having an information recording section characterized by being ";
(8) “The member having the information storage unit according to (7), wherein the member having the information storage unit is any one of a card, a disk, a disk cartridge, and a tape cassette”;
(9) “In the support constituting the reversible thermosensitive recording medium according to any one of (1) to (6), an adhesive layer or a surface opposite to the surface on which the reversible thermosensitive recording layer is provided. A reversible thermosensitive recording label characterized by providing an adhesive layer;
(10) The information storage unit according to (7) or (8), wherein a reversible display unit is provided using the reversible thermosensitive recording label according to (9). Member having;
(11) “The reversible thermosensitive recording medium according to any one of (1) to (6), the reversible thermosensitive recording label according to (9), or the above (7), (8), (10 An image processing method comprising forming and / or erasing an image by heating the reversible thermosensitive recording layer in the member having the information storage unit according to any one of
(12) “The image processing method according to (11), wherein an image is formed using a thermal head”;
(13) “The image processing method according to (11), wherein the image is erased using a thermal head or a ceramic heater”.

The reversible thermosensitive recording medium of the present invention has a reversible thermosensitive recording layer using the color-decoloring / controlling agent having the specific chemical structure, so that in image formation, the color developability and the stability of the color image are excellent. In addition, the formed image is excellent in erasability.
In addition, the member having an information storage unit and the reversible thermosensitive recording label having the reversible thermosensitive recording layer of the present invention are also excellent in the excellent color developability, color image stability and erasability.
Furthermore, the image processing method of the present invention can form and erase an image excellent in color developability, color density and erasability on the reversible thermosensitive recording layer.

Below, the coloring / decoloring controlling agent used in the present invention will be described.
The coloring / decoloring control agent used in the present invention is a compound represented by the following general formula [1].

（式［１］中、Ａは炭素数６〜２４の鎖状の炭化水素基、または置換基を有していてもよい芳香環基を示し、Ｂは置換基を有していてもよい芳香環基もしくは複素環基を示す。）

(In the formula [1], A represents a chain hydrocarbon group having 6 to 24 carbon atoms, or an aromatic ring group that may have a substituent, and B represents an aromatic that may have a substituent. Represents a cyclic group or a heterocyclic group.)

  A represents a chain hydrocarbon group having 6 to 24 carbon atoms or an aromatic ring group which may have a substituent, preferably a chain hydrocarbon group having 10 to 22 carbon atoms, more preferably A hydrocarbon group having 12 to 22 carbon atoms, or an alkyl group, alkenyl group, allyl group, alkoxy group, allyloxy group, alkylcarbonyl group, alkylcarbonyloxy group, alkoxycarbonyl group, alkylsulfonyl group, alkylcarbonylamino Group, an alkylaminocarbonyl group, a nitro group, an amino group, an alkylamino group, a cyano group, an aromatic ring group substituted with a halogen atom, or an unsubstituted aromatic ring group. B represents an alkyl group, alkenyl group, allyl group, alkoxy group, allyloxy group, alkylcarbonyl group, alkylcarbonyloxy group, alkoxycarbonyl group, alkylcarbonylamino group, alkylaminocarbonyl group, nitro group, amino group, alkylamino. An aromatic ring group or a heterocyclic group substituted by a group, a cyano group, a halogen atom, or the like, or an unsubstituted aromatic ring group or a heterocyclic group.

  Specific examples of the color development / decoloration controlling agent in the present invention are listed in Tables 1 and 2, but the present invention is not limited thereto.

  These coloring and decoloring control agents can be synthesized by reacting the corresponding aldehyde with a sulfonyl hydrazine compound in various solvents.

In the present invention, the compound represented by the general formula [1] can be used alone or in combination.

  The addition amount of the compound represented by the general formula [1] varies in an appropriate range depending on the compound used or a combination thereof, but is generally the above general formula [1] with respect to the developer in the reversible thermosensitive recording layer. 1] The represented compound is in the range of 1 to 50% by weight, preferably in the range of 5 to 50% by weight. If the amount of the compound represented by the general formula [1] is less than this range, the effect of improving the erasability is lowered, and if it exceeds 50% by weight, the sensitizing effect appears and the background fogging occurs at the time of erasing, the color density and The stability of the color image may be reduced.

The reversible thermosensitive recording medium of the present invention can form a relatively colored state and a decolored state depending on the heating temperature and / or the cooling rate after heating.
This basic coloring / decoloring phenomenon will be described.

FIG. 1 shows the relationship between the color density and temperature of the reversible thermosensitive recording medium of the present invention. The reversible thermosensitive recording medium using these leuco dyes and developers develops and decolors by the process shown in FIG. Heating the initial colorless state (A) the temperature above T ₁ in leuco dye and the developer are colored by mixing and melting (B), the colored state is fixed to quench this state. When the color development state (C) is heated, the color is erased at a temperature T ₂ lower than the color development temperature. As described above, the reversible thermosensitive recording medium can be recorded and erased by controlling the heating temperature and the cooling rate after heating.

  Next, for the developer as the electron accepting compound used in the reversible thermosensitive recording medium of the present invention, a structure having a color developing ability to develop a leuco dye in the molecule, such as a phenolic hydroxyl group, a carboxylic acid group, etc. In addition, a known developer such as a compound having one or more structures that control cohesion between molecules, for example, a structure in which long-chain hydrocarbon groups are linked can be used. The compounds represented are preferred.

（式［２］中、ｎは１〜３の整数を示し、ＸはＮ原子またはＯ原子を含む２価の基を表わす。また、Ｒ_１は置換基を有していてもよい炭素数２以上の２価の脂肪族炭化水素基を表わし、Ｒ_２は置換基を有していてもよい炭素数１〜３０の１価の脂肪族炭化水素基を表わす。）

(In the formula [2], n represents an integer of 1 to 3, X represents a divalent group containing an N atom or an O atom, and R ₁ has 2 carbon atoms which may have a substituent. The above divalent aliphatic hydrocarbon group is represented, and R ₂ represents a monovalent aliphatic hydrocarbon group having 1 to 30 carbon atoms which may have a substituent.

Here, in the general formula [2], R ₂ has 1 to 30 carbon atoms, and particularly preferably R ₂ has 8 to 22 carbon atoms. The X group is a divalent group containing an N atom or an O atom, particularly preferably an amide group and a urea group, and more preferably a urea group. Further, R ₁ represents a divalent aliphatic hydrocarbon group having 2 or more carbon atoms, and particularly preferably a divalent aliphatic hydrocarbon group having 4 or more carbon atoms.

In the general formula [2], the aliphatic hydrocarbon group may be linear or branched, and may have an unsaturated bond. Examples of the substituent bonded to the hydrocarbon group include a hydroxyl group, a halogen atom, and an alkoxy group. When the sum of the carbons of R ₁ and R ₂ is 7 or less, the stability of color development and the decoloring property are lowered. Therefore, the number of carbons is preferably 8 or more, and more preferably 11 or more.
Preferable examples of R ₁ include those shown in Table 3 below.

これらの中でも−（ＣＨ_２）ｑ−が特に好ましい。尚、式中のｑ、ｑ’、ｑ’’、ｑ’’’はそれぞれ前記Ｒ_１の炭素数を満足する整数を表わす。
また、Ｒ_２の好ましい例としては以下の表４に示すものが挙げられる。

Among them - _(CH 2) q- are particularly preferred. In the formula, q, q ′, q ″, and q ′ ″ each represent an integer satisfying the carbon number of R ₁ .
Further, preferred examples of R ₂ include those shown in Table 4 below.

これらの中でも−（ＣＨ_２）ｑ−ＣＨ_３が特に好ましい。なお、式中のｑ、ｑ’、ｑ’’、ｑ’’’はそれぞれ前記Ｒ_２の炭素数を満足する整数を表わす。

Among them _{- (CH 2) q-CH} 3 are particularly preferred. In the formula, q, q ′, q ″, and q ′ ″ each represent an integer that satisfies the carbon number of R ₂ .

  X represents a divalent group containing an N atom or an O atom, and preferably represents a divalent group having at least one group represented by Table 5. Examples thereof include those shown in Table 6. Of these, preferred groups are those shown in Table 7.

  Specific examples of the phenol compound include the following. Specific examples of the compounds represented by the general formula in Table 8 are given in Table 9 and Table 10 as examples. In addition, the same thing is mentioned about the compound represented by the other general formula in Table 7. However, the present invention is not limited to these.

  Among the compounds shown in Tables 9 and 10, preferred compounds are those in which m corresponds to 5 to 11 and n corresponds to 8 to 22 in accordance with the general formula in Table 8.

  Examples of the binder resin used for forming the reversible thermosensitive recording layer of the present invention include polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, ethyl cellulose, polystyrene, styrene copolymer, phenoxy resin, and polyester. , Aromatic polyester, polyurethane, polycarbonate, polyacrylic acid ester, polymethacrylic acid ester, acrylic copolymer, maleic acid copolymer, polyvinyl alcohol, modified polyvinyl alcohol, hydroxyethyl cellulose, carboxymethyl cellulose, starches, etc. .

  The role of these binder resins is to keep the materials of the composition uniformly dispersed without being displaced by the application of heat for recording / erasing. Therefore, it is preferable to use a resin having high heat resistance as the binder resin. For example, the binder resin may be crosslinked with heat, ultraviolet light, electron beam, or the like.

  Specific examples of the crosslinked resin used in the present invention include acrylic polyol resins, polyester polyol resins, polyurethane polyol resins, phenoxy resins, polyvinyl butyral resins, cellulose acetate propionate, and cellulose acetate butyrate. A resin having a group that reacts with the monomer, a resin obtained by copolymerization of a monomer having a group that reacts with a crosslinking agent and another monomer, or a resin having a crosslinking reactive group. It is not limited.

  Examples of the crosslinking agent used in the present invention include conventionally known isocyanates, amines, phenols, epoxy compounds and the like. Among these, an isocyanate type crosslinking agent is preferably used. The isocyanate compound used here is selected from known modified urethane monomers, allophanate modified, isocyanurate modified, burette modified, carbodiimide modified, blocked isocyanate and the like.

  Examples of the isocyanate monomer forming the modified product include tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), xylylene diisocyanate (XDI), naphthylene diisocyanate (NDI), paraphenylene diisocyanate ( PPDI), tetramethylxylylene diisocyanate (TMXDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate (HMDI), isophorone diisocyanate (IPDI), lysine diisocyanate (LDI), isopropylidenebis (4-cyclohexylisocyanate) (IPC) ), Cyclohexyl diisocyanate (CHDI), tolidine diisocyanate (TODI), and the like. It is not limited to the compounds.

Furthermore, you may use the catalyst used for this kind of reaction as a crosslinking accelerator. Examples of the crosslinking accelerator include tertiary amines such as 1,4-diaza-bicyclo [2,2,2] octane, and metal compounds such as organic tin compounds.
The total amount of the crosslinking agent added may or may not undergo a crosslinking reaction. That is, an unreacted crosslinking agent may be present. Since this type of cross-linking reaction proceeds over time, the presence of an unreacted cross-linking agent does not indicate that the cross-linking reaction has not proceeded at all, but an unreacted cross-linking agent is detected. However, this does not mean that there is no resin in a crosslinked state. Further, as a method for distinguishing whether the polymer in the present invention is in a crosslinked state or in a non-crosslinked state, it can be distinguished by immersing the coating film in a highly soluble solvent. That is, since the polymer in the non-crosslinked state dissolves in the solvent and does not remain in the solute, the presence or absence of the polymer structure of the solute may be analyzed. Therefore, if the presence of the polymer structure in the solute cannot be confirmed, the polymer can be distinguished from the crosslinked polymer because it is in a non-crosslinked state. Here, this can be expressed as a gel fraction.

  The gel fraction refers to the ratio of gel formation when a resin solute in the solvent loses its independent mobility due to interaction and collects and solidifies (gel). The resin preferably has a gel fraction of 30% or more, more preferably 50% or more, still more preferably 70% or more, and particularly preferably 80% or more. If the gel fraction is small, the durability will be reduced repeatedly. Therefore, in order to improve the gel fraction, a curable resin that is cured by heat, UV, EB or the like may be mixed in the resin, or the resin itself may be crosslinked. .

As a gel fraction measurement method, the membrane is peeled off from the support and the initial weight of the membrane is measured, and then the membrane is placed in a 400 mesh wire net and immersed in a solvent in which the resin before crosslinking is soluble for 24 hours. Then vacuum dry and measure the weight after drying.
The gel fraction calculation is performed according to the following formula.

この計算でゲル分率を算出するときに、感熱層中の樹脂成分以外の有機低分子物質粒子等の重量を除いて計算を行なう。この際、予め有機低分子物質重量が分からないときには、ＴＥＭ、ＳＥＭ等の断面観察により、単位面積あたりに占める面積比率と樹脂と有機低分子物質のそれぞれの比重により重量比率を求めて、有機低分子物質重量を算出して、ゲル分率値を算出すればよい。

When calculating the gel fraction by this calculation, the calculation is performed excluding the weight of organic low-molecular substance particles other than the resin component in the heat-sensitive layer. At this time, when the weight of the organic low molecular weight substance is not known in advance, the weight ratio is obtained from the area ratio per unit area and the specific gravity of the resin and the low molecular weight organic substance by cross-sectional observation such as TEM and SEM. The gel fraction value may be calculated by calculating the molecular substance weight.

  In the case of the above measurement, a reversible thermosensitive recording layer is provided on the support and another layer such as a protective layer is laminated thereon, or other layers are provided between the support and the thermosensitive layer. If there are other layers, as described above, first, the film thickness of the reversible thermosensitive recording layer and other layers is examined by observing the cross-section of the TEM, SEM, etc. And exposing the surface of the reversible thermosensitive recording layer, peeling the reversible thermosensitive recording layer, and measuring the gel fraction in the same manner as described above.

  In this method, when there is a protective layer made of an ultraviolet curable resin or the like in the upper layer of the reversible thermosensitive recording layer, the thickness of the protective layer is reduced and the reversible feeling is prevented in order to prevent this layer from being mixed as much as possible. The surface of the thermal recording layer must also be shaved slightly to prevent the influence on the gel fraction value.

  Examples of the leuco dye as the electron donating color-forming compound used in the present invention are listed below, but the present invention is not limited to these. In addition, leuco dyes can be used alone or in combination.

  2-anilino-3-methyl-6-diethylaminofluorane, 2-anilino-3-methyl-6-di (n-butylamino) fluorane, 2-anilino-3-methyl-6- (Nn-propyl-) N-methylamino) fluorane, 2-anilino-3-methyl-6- (N-isopropyl-N-methylamino) fluorane, 2-anilino-3-methyl-6- (N-isobutyl-N-methylamino) fluorane 2-anilino-3-methyl-6- (Nn-amyl-N-methylamino) fluorane, 2-anilino-3-methyl-6- (N-sec-butyl-N-methylamino) fluorane, 2 -Anilino-3-methyl-6- (Nn-amyl-N-ethylamino) fluorane, 2-anilino-3-methyl-6- (N-iso-amyl-N-ethylamino) Luolan, 2-anilino-3-methyl-6- (Nn-propyl-N-isopropylamino) fluorane, 2-anilino-3-methyl-6- (N-cyclohexyl-N-methylamino) fluorane, 2- Anilino-3-methyl-6- (N-ethyl-p-toluidino) fluorane, 2-anilino-3-methyl-6- (N-methyl-p-toluidino) fluorane, 2- (m-trichloromethylanilino) -3-methyl-6-diethylaminofluorane, 2- (m-trifluoromethylanilino) -3-methyl-6-diethylaminofluorane, 2- (m-trichloromethylanilino) -3-methyl-6 (N-cyclohexyl-N-methylamino) fluorane, 2- (2,4-dimethylanilino) -3-methyl-6-diethylaminofluorane 2- (N-ethyl-p-toluidino) -3-methyl-6- (N-ethylanilino) fluorane, 2- (N-ethyl-p-toluidino) -3-methyl-6- (N-propyl-p- Toluidino) fluoran, 2-anilino-6- (Nn-hexyl-N-ethylamino) fluorane, 2- (o-chloroanilino) -6-diethylaminofluorane, 2- (o-chloroanilino) -6-dibutylamino Fluorane, 2- (m-trifluoromethylanilino) -6-diethylaminofluorane, 2,3-dimethyl-6-dimethylaminofluorane, 3-methyl-6- (N-ethyl-p-toluidino) fluorane 2-chloro-6-diethylaminofluorane, 2-bromo-6-diethylaminofluorane, 2-chloro-6-dipropylaminofluorane 3-chloro-6-cyclohexylaminofluorane, 3-bromo-6-cyclohexylaminofluorane, 2-chloro-6- (N-ethyl-N-isoamylamino) fluorane, 2-chloro-3-methyl-6 -Diethylaminofluorane, 2-anilino-3-chloro-6-diethylaminofluorane, 2- (o-chloroanilino) -3-chloro-6-cyclohexylaminofluorane, 2- (m-trifluoromethylanilino)- 3-chloro-6-diethylaminofluorane, 2- (2,3-dichloroanilino) -3-chloro-6-diethylaminofluorane, 1,2-benzo-6-diethylaminofluorane, 3-diethylamino-6- (M-trifluoromethylanilino) fluorane, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-Ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -7- Azaphthalide, 3- (1-octyl-2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindole-3- Yl) -3- (2-methyl-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-methyl-4-diethylaminophenyl)- 7-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (4-diethylaminophenyl) -4-azaphthalide, 3- (1- Tyl-2-methylindol-3-yl) -3- (4-Nn-amyl-N-methylaminophenyl) -4-azaphthalide, 3- (1-methyl-2-methylindol-3-yl) -3- (2-hexyloxy-4-diethylaminophenyl) -4-azaphthalide, 3,3-bis (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3,3-bis (2-ethoxy-4) -Diethylaminophenyl) -7-azaphthalide.

  As the color former as the electron-donating color-forming compound used in the present invention, a conventionally known leuco dye can be used alone or as a mixture in addition to the fluoran compound and azaphthalide compound. The color former is shown below.

  2- (p-acetylanilino) -6- (Nn-amyl-Nn-butylamino) fluorane, 2-benzylamino-6- (N-ethyl-p-toluidino) fluorane, 2-benzylamino -6- (N-methyl-2,4-dimethylanilino) fluorane, 2-benzylamino-6- (N-ethyl-2,4-dimethylanilino) fluorane, 2-benzylamino-6- (N- Methyl-p-toluidino) fluorane, 2-benzylamino-6- (N-ethyl-p-toluidino) fluorane, 2- (di-p-methylbenzylamino) -6- (N-ethyl-p-toluidino) fluorane 2- (α-phenylethylamino) -6- (N-ethyl-p-toluidino) fluorane, 2-methylamino-6- (N-methylanilino) fluorane, 2-methyl Mino-6- (N-ethylanilino) fluorane, 2-methylamino-6- (N-propylanilino) fluorane, 2-ethylamino-6- (N-methyl-p-toluidino) fluorane, 2-methylamino- 6- (N-methyl-2,4-dimethylanilino) fluorane, 2-ethylamino-6- (N-ethyl-2,4-dimethylanilino) fluorane, 2-dimethylamino-6- (N-methylanilino) ) Fluorane, 2-dimethylamino-6- (N-ethylanilino) fluorane, 2-diethylamino-6- (N-methyl-p-toluidino) fluorane, 2-diethylamino-6- (N-ethyl-p-toluidino) fluorane 2-dipropylamino-6- (N-methylanilino) fluorane, 2-dipropylamino-6- (N-ethylanily) C) fluorane, 2-amino-6- (N-methylanilino) fluorane, 2-amino-6- (N-ethylanilino) fluorane, 2-amino-6- (N-propylanilino) fluorane, 2-amino-6 -(N-methyl-p-toluidino) fluorane, 2-amino-6- (N-ethyl-p-toluidino) fluorane, 2-amino-6- (N-propyl-p-toluidino) fluorane, 2-amino- 6- (N-methyl-p-ethylanilino) fluorane, 2-amino-6- (N-ethyl-p-ethylanilino) fluorane, 2-amino-6- (N-propyl-p-ethylanilino) fluorane, 2-amino -6- (N-methyl-2,4-dimethylanilino) fluorane, 2-amino-6- (N-ethyl-2,4-dimethylanilino) fluorane 2-amino-6- (N-propyl-2,4-dimethylanilino) fluorane, 2-amino-6- (N-methyl-p-chloroanilino) fluorane, 2-amino-6- (N-ethyl-p) -Chloroanilino) fluorane, 2-amino-6- (N-propyl-p-chloroanilino) fluorane, 1,2-benzo-6- (N-ethyl-N-isoamylamino) fluorane, 1,2-benzo-6 Dibutylaminofluorane, 1,2-benzo-6- (N-methyl-N-cyclohexylamino) fluorane, 1,2-benzo-6- (N-ethyl-N-toluidino) fluorane, and others.

  In the reversible thermosensitive recording medium of the present invention, an additive for improving or controlling the coating characteristics and color developing / decoloring characteristics of the reversible thermosensitive recording layer can be used as necessary. These additives include, for example, surfactants, conductive agents, fillers, antioxidants, light stabilizers, and color stabilizers.

  The appropriate ratio of the color former to the color developer varies depending on the combination of the compounds used, but the developer is generally in the range of 0.1 to 20 with respect to the color developer 1 in molar ratio, preferably 0. In the range of 2-10. If the amount of the developer is less or more than this range, the density of the colored state is lowered, which causes a problem. In addition, the color former and the developer can be used in a microcapsule. The ratio of the color developing component to the resin in the reversible thermosensitive recording layer is preferably 0.1 to 10 parts by weight with respect to 1 part by weight of the color developing component, and if less than this, the heat intensity of the reversible thermosensitive recording layer is insufficient. If it is more, the color density is lowered, which causes a problem.

  For the formation of the reversible thermosensitive recording layer, for example, a coating solution prepared by uniformly mixing and dispersing the above-mentioned developer, color former, various additives, a crosslinking agent and a crosslinkable resin, and a coating solvent. Is used.

  Specific examples of the solvent used for preparing the coating liquid include water; alcohols such as methanol, ethanol, isopropanol, n-butanol, and methyl isocarbinol; acetone, 2-butanone, ethyl amyl ketone, diacetone alcohol, isophorone, and cyclohexanone. Ketones such as N; N-dimethylformamide, amides such as N, N-dimethylacetamide; ethers such as diethyl ether, isopropyl ether, tetrahydrofuran, 1,4-dioxane, and 3,4-dihydro-2H-pyran Glycol ethers such as 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, ethylene glycol dimethyl ether; 2-methoxyethyl acetate, 2-ethoxyethyl acetate, 2-butoxyethyl Glycol ether acetates such as acetate; Esters such as methyl acetate, ethyl acetate, isobutyl acetate, amyl acetate, ethyl lactate, and ethylene carbonate; Aromatic hydrocarbons such as benzene, toluene, and xylene; Hexane, heptane, iso-octane Aliphatic hydrocarbons such as cyclohexane; halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, dichloropropane, chlorobenzene; sulfoxides such as dimethyl sulfoxide; N-methyl-2-pyrrolidone, N-octyl Examples include pyrrolidones such as -2-pyrrolidone.

  The coating liquid can be prepared using a known coating liquid dispersing apparatus such as a paint shaker, a ball mill, an attritor, a three-roll mill, a keddy mill, a sand mill, a dyno mill, or a colloid mill. In addition, each material may be dispersed in a solvent using the above-described coating liquid dispersing apparatus, or may be dispersed and mixed in a solvent alone. Further, it may be dissolved by heating and precipitated by rapid cooling or cooling.

  There is no particular limitation on the coating method for providing the reversible thermosensitive recording layer, blade coating, wire bar coating, spray coating, air knife coating, bead coating, curtain coating, gravure coating, kiss coating, Known methods such as reverse roll coating, dip coating, and die coating can be used.

  In the present invention, a heat insulating layer can be provided between the support and the reversible thermosensitive recording layer in order to improve the color development sensitivity by effectively using the heat applied to the medium during recording. The heat insulating layer can be formed by coating using a binder resin containing organic or inorganic fine hollow body particles.

For the heat insulating layer, the same resin as the resin for the reversible thermosensitive recording layer, intermediate layer and protective layer can be used. The heat insulating layer can contain inorganic fillers such as calcium carbonate, magnesium carbonate, titanium oxide, silicon oxide, aluminum hydroxide, kaolin, and talc and / or various organic fillers. In addition, a surfactant, a dispersant, and the like can be contained.
Moreover, when providing the said heat insulation layer, generation | occurrence | production of a crack and generation | occurrence | production of a burr | flash are improved by providing through an adhesive layer.
The adhesive layer can be formed by the same coating method as that for each of the above layers.

  The support for the reversible thermosensitive recording medium of the present invention is paper, resin film, PET film, synthetic paper, metal foil, glass or a composite thereof, and the like, as long as it can hold the reversible thermosensitive recording layer. . Moreover, the thing of the thickness as needed can be used individually or by bonding. That is, a support having an arbitrary thickness from about several μm to about several mm is used. These supports may have a magnetic recording layer on the same surface and / or the opposite surface as the reversible thermosensitive recording layer. The reversible thermosensitive recording medium of the present invention may be attached to another medium via an adhesive layer or the like. Alternatively, a back coat layer is provided on one side of a support such as a PET film, the release layer used for the thermal transfer ribbon on the opposite side of the back coat layer, the thermal recording layer of the present invention on the release layer, and paper on the surface, A resin layer that can be transferred to a resin film, a PET film, or the like may be provided and transferred using a thermal transfer printer. The reversible thermosensitive recording medium of the present invention may be processed into a sheet shape or a card shape, and the shape can be processed into an arbitrary shape, and printing on the surface of the medium can be performed. In the reversible thermosensitive recording medium of the present invention, an irreversible thermosensitive recording layer may be used in combination, and at this time, the color tone of each recording layer may be the same or different.

As a method for drying / curing the recording layer, after coating and drying, a curing treatment is performed as necessary. The heat treatment may be performed at a relatively high temperature for a short time using a high-temperature bath or the like, or may be heat-treated at a relatively low temperature for a long time. As specific conditions for the crosslinking reaction, it is preferable to heat from about 1 minute to 150 hours under a temperature condition of about 30 ° C. to 130 ° C. from the viewpoint of reactivity. More preferably, heating is performed for about 2 minutes to 120 hours under a temperature condition of 40 ° C to 100 ° C. In addition, since productivity is emphasized in production, it is difficult to take time until the crosslinking is sufficiently completed. Therefore, a crosslinking step may be provided separately from the drying step. As a condition for the crosslinking step, it is preferable to heat at a temperature of 40 ° C. to 100 ° C. for about 2 minutes to 120 hours.
The film thickness of the reversible thermosensitive recording layer is preferably in the range of 1 to 20 μm, more preferably 3 to 15 μm.

  Further, according to the present invention, a protective layer containing a resin in a crosslinked state can be provided on the reversible thermosensitive recording layer. As the resin used for the protective layer, the same thermosetting resin, ultraviolet curable resin, and electron beam curable resin as those used for the recording layer are used.

  Improvement of adhesion between reversible thermosensitive recording layer and protective layer, prevention of alteration of reversible thermosensitive recording layer by application of protective layer, transfer of additives contained in protective layer to reversible thermosensitive recording layer, or reversible thermosensitive recording In order to prevent the additive contained in the layer from moving to the protective layer, an intermediate layer may be provided between them. The thickness of the intermediate layer is preferably in the range of 0.1 to 20 μm, more preferably 0.3 to 10 μm. As the solvent used in the intermediate layer coating solution, the dispersion device of the coating solution, the binder, the coating method, the drying / curing method, etc., known methods used in the reversible thermosensitive recording layer can be used.

  In the formation of the protective layer, the thickness of the protective layer of the reversible thermosensitive recording layer is preferably in the range of 0.1 to 20 μm, more preferably 0.3 to 10 μm. As the solvent, the coating liquid dispersing device, the binder, the coating method, the drying / curing method, and the like used in the protective layer coating solution, known methods used in the reversible thermosensitive recording layer can be used.

  Other fillers that do not have UV absorbing performance or UV shielding performance may be added to the reversible thermosensitive recording layer, intermediate layer, and protective layer, and the filler can be divided into inorganic fillers and organic fillers. Examples of the inorganic filler include calcium carbonate, magnesium carbonate, silicic anhydride, alumina, iron oxide, calcium oxide, magnesium oxide, chromium oxide, manganese oxide, silica, talc, and mica.

  Organic fillers include silicone resin, cellulose resin, epoxy resin, nylon resin, phenol resin, polyurethane resin, urea resin, melamine resin, polyester resin, polycarbonate resin, styrene, such as styrene, polystyrene, polystyrene isoprene, styrene vinylbenzene Examples thereof include resins, acrylic resins such as vinylidene chloride acrylic, acrylic urethane, and ethylene acrylic, polyethylene resins, formaldehyde resins such as benzoguanamine formaldehyde, melamine formaldehyde, polymethyl methacrylate resins, and vinyl chloride resins. In the present invention, the filler can be used alone, but two or more kinds may be contained. In the case of a plurality, there are no particular limitations on how to combine the inorganic filler and the organic filler. Examples of the shape include a spherical shape, a granular shape, a plate shape, and a needle shape. Content of the filler in a protective layer is 5-50 volume% by a volume fraction.

  A lubricant may be added to the reversible thermosensitive recording layer, intermediate layer, and protective layer. Specific examples of the lubricant include synthetic waxes such as ester wax, paraffin wax, and polyethylene wax: vegetable waxes such as hardened castor oil: Animal waxes such as beef tallow oil: higher alcohols such as stearyl alcohol and behenyl alcohol: higher fatty acids such as margaric acid, lauric acid, mystynolic acid, palmitic acid, stearic acid, behenic acid, and fumenic acid: fatty acid ester of sorbitan Higher fatty acid esters such as stearic acid amide, oleic acid amide, lauric acid amide, ethylene bis stearic acid amide, methylene bis stearic acid amide, methylol stearic acid amide and the like. The content of the lubricant in the layer is preferably 0.1 to 95%, more preferably 1 to 75% in terms of volume fraction.

The reversible thermosensitive recording label of the present invention is one in which an adhesive layer or a pressure-sensitive adhesive layer is provided on the surface opposite to the surface provided with the reversible thermosensitive recording layer of the support constituting the reversible thermosensitive recording medium described above. is there.
This reversible thermosensitive recording label includes an adhesive layer or a pressure-sensitive adhesive layer (non-peeling paper type), and a release paper attached under the adhesive layer or pressure-sensitive adhesive layer (peeling paper type). As a material constituting the adhesive layer, a hot melt type material is usually used.

Commonly used materials can be used for the adhesive layer or the pressure-sensitive adhesive layer.
For example, urea resin, melamine resin, phenol resin, epoxy resin, vinyl acetate resin, vinyl acetate-acrylic copolymer, ethylene-vinyl acetate copolymer, acrylic resin, polyvinyl ether resin, vinyl chloride-vinyl acetate Copolymer, polystyrene resin, polyester resin, polyurethane resin, polyamide resin, chlorinated polyolefin resin, polyvinyl butyral resin, acrylic ester copolymer, methacrylic ester copolymer, natural rubber , Cyanoacrylate resins, silicon resins, and the like, but are not limited thereto.

  The reversible thermosensitive recording medium of the present invention is produced by causing at least the reversible thermosensitive layer constituting the reversible thermosensitive recording medium to function as a reversible display unit and a member having an information storage function (information storage unit). It can be used as an information display storage member (a member having an information storage unit).

Next, the information display storage member will be described.
The members having the information storage unit and the reversible display unit can be roughly classified into the following three items.
(1) A member having an information storage function is used as a support for a reversible thermosensitive recording medium, and a reversible thermosensitive layer is directly formed thereon.
(2) The support surface of a reversible thermosensitive recording medium which has a reversible thermosensitive layer formed on a support and is separately bonded to a member having an information storage function.
(3) The reversible thermosensitive recording label bonded to a member having an information storage function via an adhesive layer or an adhesive layer.

In these cases (1), (2), and (3), it is necessary to set the functions of the information storage unit and the reversible display unit so that the functions can be performed. Can be arbitrarily selected according to the purpose, and can be provided on the surface of the reversible thermosensitive recording medium opposite to the surface provided with the reversible thermosensitive layer, between the support and the thermosensitive layer, or the thermosensitive layer. It can also be provided on a part of the top.
The member having the information storage unit is not particularly limited, but a general card, disk, disk cartridge, or tape cassette can be used.

Examples of these include thick cards such as IC cards and optical cards, flexible disks, magneto-optical recording disks (MD), disk cartridges with built-in disks that can rewrite storage information such as DVD-RAM, and CD-RWs. Examples thereof include a disc that does not use a disc cartridge, a write-once disc such as a CD-R, an optical information recording medium (CD-RW) that uses a phase-change storage material, and a video tape cassette.
The information display storage member having both the reversible display function and the information storage function will be described in the case of a card, for example, by displaying a part of the information stored in the information storage unit on the reversible thermosensitive recording layer. The owner or the like can confirm information by looking at the card without a special device, and the convenience is greatly improved compared to a card to which the reversible thermosensitive recording medium is not applied.

The information storage unit is not particularly limited as long as it can store necessary information. For example, magnetic recording, contact IC, non-contact IC, or optical memory is useful.
The magnetic recording layer is formed by coating the support using a commonly used metal compound such as iron oxide or barium ferrite and a resin such as vinyl chloride, urethane or nylon, or without using a resin. It forms by methods, such as vapor deposition and sputtering, using the said metal compound. In addition, the reversible thermosensitive recording layer in the reversible thermosensitive recording medium used for display can be used as a display unit in a manner such as a barcode or a two-dimensional code.

In addition, as an example of using the reversible thermosensitive recording label of (3) above, when the reversible thermosensitive recording layer is difficult to apply as a support, such as a vinyl chloride card with a magnetic stripe, An adhesive layer or a pressure-sensitive adhesive layer can be provided on the entire surface or a part (see FIGS. 2 to 4).
By doing so, the convenience of this medium can be improved, such as being able to display a part of the information stored in the magnetism.
The reversible thermosensitive recording label provided with the adhesive layer or the pressure-sensitive adhesive layer is applicable not only to the above-described magnetic PVC card but also to a thick card such as an IC card or an optical card.

Further, the reversible thermosensitive recording label can be used in place of a display label on a disk cartridge having a built-in disk capable of rewriting storage information such as a flexible disk, MD, DVD-RAM and the like.
Further, in the case of a disc that does not use a disc cartridge such as a CD-RW, a reversible thermosensitive recording label can be directly attached to the disc, or a reversible thermosensitive recording layer can be provided directly on the disc. By doing so, it is possible to apply to applications such as automatically changing display contents in accordance with changes in the stored contents.

The reversible thermosensitive recording label of the present invention can also be displayed by rewriting a part of the stored information added to the CD-R by sticking the reversible thermosensitive recording label on a write-once disc such as a CD-R.
Further, it may be used as a display label for a video tape cassette.
As a method of providing a thermoreversible recording function on a thick card, a disc cartridge, and a disc, in addition to the method of applying the reversible thermosensitive recording label, a method of directly applying a reversible thermosensitive recording layer on them, There is a method of forming a reversible thermosensitive recording layer on the support and transferring the thermosensitive recording layer onto a thick card, a disc cartridge, or a disc.
When transferring, an adhesive layer such as a hot melt type or an adhesive layer may be provided on the reversible thermosensitive recording layer.
When attaching a reversible thermosensitive recording label or providing a reversible thermosensitive recording layer on a rigid object such as a thick card, disk, disk cartridge, tape cassette, etc., improve the contact with the thermal head. In order to form an image uniformly, it is preferable to provide an elastic cushioning layer or sheet between the rigid substrate and the label or the reversible thermosensitive recording layer.

  The present invention further provides an image processing method, wherein the reversible thermosensitive recording medium, the member having the information storage unit or the label is used to form and / or erase an image by heating. FIG. 5 shows a schematic diagram of an image processing method using a member having an information storage unit.

For image formation, an image recording means such as a thermal head, a laser or the like that can partially heat the medium on the image is used. For erasing the image, an image erasing means such as a hot stamp, a ceramic heater, a heat roller, hot air, a thermal head, or a laser is used.
Among these, a ceramic heater is preferably used. By using a ceramic heater, the apparatus can be miniaturized, a stable erased state can be obtained, and an image with good contrast can be obtained.
The set temperature of the ceramic heater is preferably 90 ° C. or higher, and more preferably 100 ° C. or higher.

Further, by using a thermal head as the image erasing means, it is possible to further reduce the size of the entire apparatus, to reduce power consumption, and to realize a battery-driven handy type apparatus. If a single thermal head is used for both forming and erasing, the size can be further reduced.
When forming and erasing with a single thermal head, once the previous image has been erased, a new image may be formed again. The energy is changed for each image, and the previous image is erased at one time. It is also possible to use an overwrite method that forms the film.
In the overwrite method, the time required for forming and erasing the image is reduced, and the recording speed is increased. In the case of using a card having a reversible thermosensitive recording layer and an information storage unit, the above device includes means for reading and rewriting the memory of the information storage unit.

  Hereinafter, the present invention will be described in more detail with reference to examples. In the examples, “parts” and “%” are based on weight.

Example 1
<Preparation of reversible thermosensitive recording layer>
The following composition was pulverized and dispersed to a particle size of 1 to 4 μm using a ball mill.
[Liquid A]
4 parts of developer expressed by the following structural formula

下記の構造式で表わされる発色消色制御剤 １部

1 part of coloring and decoloring control agent represented by the following structural formula

アクリルポリオール樹脂（三菱レイヨン社製ＬＲ５０３
固形分濃度５０％溶液） １２部
メチルエチルケトン ７０部
得られた分散液に２−アニリノ−３−メチル−６−ジエチルアミノフルオラン１部を加え、よく撹拌し記録層塗布液を調製した。上記組成の記録層塗布液を、厚さ１８８μｍの白ＰＥＴにワイヤーバーを用いて塗布し、１００℃、２分で乾燥した後、膜厚約８．０μｍの記録層を設けた。

Acrylic polyol resin (LR503 manufactured by Mitsubishi Rayon Co., Ltd.)
(Solid content concentration 50% solution) 12 parts Methyl ethyl ketone 70 parts 1 part of 2-anilino-3-methyl-6-diethylaminofluorane was added to the obtained dispersion and stirred well to prepare a recording layer coating solution. The recording layer coating solution having the above composition was applied to white PET having a thickness of 188 μm using a wire bar and dried at 100 ° C. for 2 minutes, and then a recording layer having a thickness of about 8.0 μm was provided.

  An intermediate layer liquid having the following composition was applied onto the recording layer using a wire bar, dried at 90 ° C. for 1 minute, and then heated at 60 ° C. for 2 hours to provide an intermediate layer having a thickness of about 2.0 μm. Furthermore, after coating a protective layer solution having the following composition using a wire bar, the coating is cured by passing under a UV lamp with an irradiation energy of 80 W / cm at a conveying speed of 12 m / min to provide a protective layer having a thickness of 3 μm. A reversible thermosensitive recording medium of the present invention was produced.

[Intermediate layer liquid]
Polyester polyol resin (Takelac U-21, Takeda Pharmaceutical Company Limited)
10% methyl ethyl ketone (MEK) solution 100 parts Zinc oxide (Sumitomo Osaka Cement) 10 parts Coronate HL (Nippon Polyurethane) 15 parts

[Protective layer solution]
Urethane acrylate UV curable resin
(C7-157 manufactured by Dainippon Ink & Co.) 10 parts Silica (P-527 manufactured by Mizusawa Chemical Co., Ltd.) 1.5 parts 90 parts ethyl acetate

Example 2
A reversible thermosensitive recording medium was produced in the same manner as in Example 1 except that the developer was changed to the compound represented by the following structural formula in Example 1.

Example 3
A reversible thermosensitive recording medium was produced in the same manner as in Example 1 except that the following recording layer coating solution was used instead of the recording layer coating solution used in Example 1.
<Preparation of reversible thermosensitive recording layer>
4 parts of developer expressed by the following structural formula

下記の構造式で表わされる発色消色制御剤 １部

1 part of coloring and decoloring control agent represented by the following structural formula

アクリルポリオール樹脂の５０％メチルエチルケトン（ＭＥＫ）溶液 ９部
メチルエチルケトン（ＭＥＫ） ７０部

9 parts of 50% methyl ethyl ketone (MEK) solution of acrylic polyol resin 70 parts of methyl ethyl ketone (MEK)

  The composition was pulverized and dispersed to a mean particle size of about 1 μm using a ball mill. To the obtained dispersion, 1 part of 2-anilino-3-methyl-6-diethylaminofluorane and 2 parts of Coronate HL (adduct type hexamethylene diisocyanate 75% ethyl acetate solution) manufactured by Nippon Polyurethane Co., Ltd. were added and stirred well. A layer coating solution was prepared. The recording layer coating liquid having the above composition was applied to white PET having a thickness of 188 μm using a wire bar, dried at 100 ° C. for 2 minutes, and then heated at 60 ° C. for 24 hours to have a film thickness of about 8.0 μm. A recording layer was provided to produce a reversible thermosensitive recording medium.

Example 4
A reversible thermosensitive recording medium was prepared in the same manner as in Example 1 except that the developer was changed to the compound represented by the following structural formula in Example 3.

Example 5
A reversible thermosensitive recording medium was produced in the same manner as in Example 4 except that the color development / decoloration controlling agent in Example 4 was changed to a compound represented by the following structural formula.

Example 6
A reversible thermosensitive recording medium was produced in the same manner as in Example 4 except that the color development / decoloration controlling agent in Example 4 was changed to a compound represented by the following structural formula.

Example 7
A reversible thermosensitive recording medium was produced in the same manner as in Example 4 except that the color development / decoloration controlling agent in Example 4 was changed to a compound represented by the following structural formula.

Example 8
After coating with the wire bar using the following heat insulating layer liquid on the same support as in Example 1, drying was performed at 80 ° C. for 2 minutes to form a heat insulating layer having a thickness of about 20 μm. Further, the reversible thermosensitive recording layer, intermediate layer and protective layer of Example 4 were applied in the same manner as in Example 1 to produce a reversible thermosensitive recording medium.

<Preparation of heat insulation layer liquid>
Styrene-butadiene copolymer
(Nippon A & L, PA-9159) 30 parts Polyvinyl alcohol (Kuraray, Poval PVA103) 12 parts Hollow particles (Matsumoto Yushi Co., Ltd., Microsphere R-300) 20 parts Water 40 parts Add the above composition, The heat insulating layer solution was stirred for about 1 hour until the heat insulating layer solution was dispersed in a uniform state to produce a heat insulating layer solution.

Comparative Example 1
A reversible thermosensitive recording medium was produced in the same manner as in Example 1 except that the color developing / decoloring controlling agent was omitted in Example 1.

Comparative Example 2
A reversible thermosensitive recording medium was produced in the same manner as in Example 3 except that the color developing / decoloring controlling agent was omitted in Example 3.

Comparative Example 3
A reversible thermosensitive recording medium was produced in the same manner as in Example 4 except that the color developing / decoloring controlling agent was omitted in Example 4.

Comparative Example 4
A reversible thermosensitive recording medium was produced in the same manner as in Example 1 except that the following recording layer was used instead of the recording layer used in Example 1.
<Preparation of reversible thermosensitive recording layer>
4 parts of developer expressed by the following structural formula

1 part of coloring and decoloring control agent represented by the following structural formula

アクリルポリオール樹脂の５０％メチルエチルケトン（ＭＥＫ）溶液 ９部
メチルエチルケトン（ＭＥＫ） ７０部

9 parts of 50% methyl ethyl ketone (MEK) solution of acrylic polyol resin 70 parts of methyl ethyl ketone (MEK)

  The composition was pulverized and dispersed to a mean particle size of about 1 μm using a ball mill. To the obtained dispersion, 1 part of 2-anilino-3-methyl-6-diethylaminofluorane and 2 parts of Coronate HL (adduct type hexamethylene diisocyanate 75% ethyl acetate solution) manufactured by Nippon Polyurethane Co., Ltd. were added and stirred well. A layer coating solution was prepared. The recording layer coating liquid having the above composition was applied to white PET having a thickness of 188 μm using a wire bar, dried at 100 ° C. for 2 minutes, and then heated at 60 ° C. for 24 hours to have a film thickness of about 8.0 μm. A recording layer was provided to produce a reversible thermosensitive recording medium.

Comparative Example 5
A reversible thermosensitive recording medium was produced in the same manner as in Comparative Example 4 except that the color development / decoloration controlling agent in Comparative Example 4 was changed to a compound having the following structure.

The reversible thermosensitive recording medium produced as described above was printed under the conditions of a voltage of 20 V and a pulse width of 2 msec using a thermal printing simulator manufactured by Yashiro Seisakusho in an environment of an air temperature of 23 ° C. and a relative humidity of 50% RH. A printed sample was prepared, and the color density and background density were measured using a Macbeth densitometer RD914.
The obtained print sample was erased from the voltage 9 V to 16.5 V in 0.5 V increments under the condition of a pulse width of 6 msec, and the density was measured in the same manner. The remaining concentration was determined.

  Next, the print sample prepared as described above is stored in a high temperature (55 ° C., 20% RH) environment for 24 hours, and the image density before and after storage is measured using a Macbeth densitometer RD914. The concentration residual ratio (residual ratio) was determined.

  Table 11 shows the above results.

  In Examples 1 to 8, the erasability is improved while maintaining a high color density and stability of the color image.

It is a figure which shows the color development and decoloring characteristic of the reversible thermosensitive coloring composition of this invention. It is a figure which shows the example which affixed the reversible thermosensitive recording label of this invention on the disk cartridge of MD. It is a figure which shows the example which affixed the reversible thermosensitive recording label of this invention on CD-RW. It is a figure which shows the example which used the reversible thermosensitive recording label of this invention as a display label of a videotape cassette. It is a figure which shows the example of the image processing apparatus of this invention.

Explanation of symbols

34 Magnetic head 38 Ceramic heater 40 Conveying roller 47 Conveying roller 53 Thermal head

Claims (13)

A reversible that can form a relatively colored state and a decolored state on the support using at least an electron-donating color-forming compound and an electron-accepting compound, depending on the heating temperature and / or the cooling rate after heating. In a reversible heat-sensitive recording medium comprising a reversible heat-sensitive recording layer containing a heat-sensitive composition, the reversible heat-sensitive recording layer contains a compound represented by the following general formula [1] as a color development / decoloration controlling agent. A reversible thermosensitive recording medium.

(In the formula [1], A represents a chain hydrocarbon group having 6 to 24 carbon atoms, or an aromatic ring group that may have a substituent, and B represents an aromatic that may have a substituent. Represents a cyclic group or a heterocyclic group.) The reversible thermosensitive recording medium according to claim 1, wherein the electron-accepting compound contains a compound that is a phenol compound represented by the following general formula [2].

(In the formula [2], n represents an integer of 1 to 3, X represents a divalent group containing an N atom or an O atom, and R ₁ has 2 carbon atoms which may have a substituent. The above divalent aliphatic hydrocarbon group is represented, and R ₂ represents a monovalent aliphatic hydrocarbon group having 1 to 30 carbon atoms which may have a substituent.   The reversible thermosensitive recording medium according to claim 2, wherein the electron-accepting compound is a phenol compound in which X is a urea group in the general formula [2].   The reversible thermosensitive recording medium according to any one of claims 1 to 3, wherein the reversible thermosensitive recording layer contains a resin in a crosslinked state.   5. The reversible thermosensitive recording medium according to claim 1, wherein a protective layer is provided on the reversible thermosensitive recording layer directly or via an intermediate layer.   6. The reversible thermosensitive recording medium according to claim 1, further comprising a heat insulating layer between the support and the reversible thermosensitive recording layer.   It has an information storage part and a reversible display part, and this reversible display part consists of a reversible thermosensitive recording layer which constitutes a reversible thermosensitive recording medium according to any one of claims 1 to 6. A member having an information recording unit.   8. The member having an information storage unit according to claim 7, wherein the member having the information storage unit is one of a card, a disk, a disk cartridge, and a tape cassette.   The support constituting the reversible thermosensitive recording medium according to any one of claims 1 to 6, wherein an adhesive layer or a pressure-sensitive adhesive layer is provided on a surface opposite to the surface provided with the reversible thermosensitive recording layer. A reversible thermosensitive recording label.   The member having the information storage unit according to claim 7 or 8, wherein the reversible thermosensitive recording label according to claim 9 is used to provide a reversible display unit.   A member having the reversible thermosensitive recording medium according to any one of claims 1 to 6, the reversible thermosensitive recording label according to claim 9, or the information storage unit according to any one of claims 7, 8, and 10. An image processing method comprising: forming and / or erasing an image by heating a reversible thermosensitive recording layer.   The image processing method according to claim 11, wherein an image is formed using a thermal head. The image processing method according to claim 11, wherein the image is erased using a thermal head or a ceramic heater.

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