JP3635310B2 - Thermoreversible recording medium, card, label, disk cartridge, disk, manufacturing method thereof, and image processing method - Google Patents

Description

【００４２】
【表２】

【００４３】
上記No.(15)の物質(HOOC・(CH₂)₅-NHCO(CH₂)₁₀-CONH-(CH₂)₅・COOH)の合成例を以下に示すが、これに限定されるものではない。
アミノカプロン酸エチル−塩酸塩８１．６ｇ、ビリジン３３．０ｇ、ドデカン二酸３２．０ｇ、１−ヒドロキシベンゾトリアゾール６３．９ｇをテトラヒドロフラン５００ｍｌに溶解し、次いで室温下でジイソプロピルカルボジイミド５２．５ｇを滴下した。滴下後還流下で３時間撹拌した後、この反応液に水酸化ナトリウム１７０ｇを溶解させた９０％エタノール水溶液８００ｍｌを加え、還流下４時間撹拌した。反応液を４Ｎ−塩酸で酸性とし、析出した結晶を濾別、水洗、乾燥後、ジメチルホルムアミドから再結晶し、目的の化合物２９．７ｇを得た。上記No.（1）〜No.（14）の物質、No.（16）〜No.（22）の物質は使用する原料を変えることにより同じ方法で合成することが可能である。
【００４４】
上記No.(24)の物質(HOOC-(CH₂)₄-CONH(CH₂)₁₀-NHCO-(CH₂)₄-COOH)の合成例を以下に示すが、これに限定されるものではない。
アジピン酸モノエチルエステル１０．０ｇ、1,10−ジアミノデカン４８．８ｇ、1-ヒドロキシベンゾトリアゾール３５．８ｇをテトラヒドロフラン１２００ｍｌに溶解し、次いで室温下でジイソプロピルカルボジイミド２９．４ｇを溶解した９０％エタノール水溶液１５００ｍｌを加え、還流下に４時間撹拌した。反応液を４Ｎ−塩酸で酸性とし、析出した結晶を濾別、水洗、乾燥後、ジメチルホルムアミドから再結晶し、目的の化合物１６．４ｇを得た。
上記No.（30）の物質、No.（33）の物質の合成例を下記に示すが、これらに限定されるものではない。
【００４５】
No.(30）の物質（CH₃-(CH₂)₁₇-NHCONH-(CH₂)₂-COOH)の合成例
β−アラニンナトリウム塩２３．９ｇ、オクタデシルイソシアネート３５．５ｇ、２−ブタノン９００ｍｌを仕込み、還流下で６時間撹拌した。次いで、析出した結晶を瀘別、水洗後、酢酸水溶液中に投じ３時間撹拌した後、再び結晶を瀘別した。得られた結晶を水洗、乾燥後トルエンから再結晶し、目的の化合物２５．７ｇを得た。
【００４６】
No.（33）の物質(CH₃-(CH₂)₁₇-SO₂-(CH₂)₂-COOH)の合成例
１−オクタデセン７５．６ｇ、チオプロピオン酸２６．８ｇ、２−ブタノン２００ｍｌを仕込み、還流下で１２時間撹拌した。この反応液に水を加え析出した結晶を瀘別、水洗後、５００ｍｌ酢酸中に投じた。次いで８０〜９０℃にて３０％過酸化水素水４５０ｍｌを滴下し、１０時間撹拌した。その後析出した結晶を瀘別、水洗いし、イソプロパノールから再結晶し、目的の化合物３２．７ｇを得た。
【００４７】
前記長鎖炭化水素含有化合物（Ｂ）は、上記の融点の範囲にあり、長鎖構造を有するものならば何でもよい。該長鎖構造の炭素数は８以上が好ましく、１０以上が更に好ましく、１２以上が特に好ましい。また、５０以下が好ましく、４０以下が更に好ましく、３０以下が特に好ましい。
【００４８】
この長鎖炭化水素含有化合物（Ｂ）としては、アルカノール；アルカンジオール；ハロゲンアルカノール又はハロゲンアルカンジオール；アルキルアミン；アルカン；アルケン；アルキン；ハロゲンアルカン；ハロゲンアルケン；ハロゲンアルキン；シクロアルカン；シクロアルケン；シクロアルキン；飽和又は不飽和モノ又はジカルボン酸又はこれらのエステル、アミド又はアンモニウム塩；飽和又は不飽和ハロゲン脂肪酸又はこれらのエステル、アミド又はアンモニウム塩；アリルカルボン酸又はそれらのエステル、アミド又はアンモニウム塩；ハロゲンアリルカルボン酸又はそれらのエステル、アミド又はアンモニウム塩；チオアルコール；チオカルボン酸又はそれらのエステル、アミン又はアンモニウム塩；チオアルコールのカルボン酸エステル等が挙げられる。これらは単独で又は２種以上混合して使用される。これらの化合物の炭素数は１０〜６０、好ましくは１０〜３８、特に１０〜３０が好ましい。エステル中のアルコール基部分は飽和していてもよく、飽和していなくてもよく、またハロゲン置換されていてもよい。いずれにしても有機低分子物質は分子中に酸素、窒素、硫黄及びハロゲンの少なくとも１種、例えば−ＯＨ、−ＣＯＯＨ、−ＣＯＮＨ、−ＣＯＯＲ、−ＮＨ、−ＮＨ₂、−Ｓ−、−Ｓ−Ｓ−、−Ｏ−、ハロゲン等を含む化合物であることが好ましい。
【００４９】
具体的には、脂肪族モノカルボン酸、脂肪族ジカルボン酸、脂肪酸エステル、高級アルキル基を有するケトン、二塩基酸エステル、多価アルコールジ脂肪酸エステル、脂肪酸モノアミド、次の一般式（３）で表わされる物質、一般式（４）で表わされる物質、が挙げられるが、これらに限定されるものではない。
【００５０】
【化７】
CH₃(CH₂)n−Ｘ−(CH₂）m−ＣＯＯＨ・・・・・一般式（３）
（ここで、一般式（３）の物質の融点は１３０℃未満であり、２６≧ｎ≧０、２６≧ｍ≧０、ただしｎ＋ｍ≧１０であり、ＺはＮＨＣＯＮＨ、ＳＯ₂、ＣＯＮＨ、又は、ＮＨＣＯを表わす。）
【００５１】
【化８】
HOOC−(CH₂)n−NHCO−(CH₂)m−COOH・・・・・一般式（４）
（ここで、一般式（４）の物質の融点は１３０℃未満であり、２６≧ｎ≧０、２６≧ｍ≧０、ただしｎ＋ｍ≧１０である。）
【００５２】
以下にさらに具体的な例を挙げるが、これらに限定されるものではない。
即ち、脂肪族モノカルボン酸の具体例としては、例えば、ラウリン酸、トリデシル酸、ミリスチン酸、ペンタデシル酸、パルミチン酸、マルガリン酸、ステアリン酸、ノナデシル酸、アラキジン酸、ベヘン酸、リグノセリン酸、セロチン酸、モンタン酸、メリシン酸等が挙げられる。
【００５３】
脂肪族ジカルボン酸の具体例としては、例えば、コハク酸、グルタル酸、アジピン酸、ピメリン酸、スベリン酸、アゼライン酸、セバシン酸、ウンデカン二酸、ドデカン二酸、テトラデカン二酸、ペンタデカン二酸、ヘキサデカン二酸、ヘプタデカン二酸、オクタデカン二酸、ノナデカン二酸、エイコサン二酸、ヘンエイコサン二酸、ドコサン二酸等が挙げられる。
【００５４】
脂肪酸エステルの具体例としては、例えば、ラウリン酸オクタデシル、ラウリン酸ドコシル、ミリスチン酸ドコシル、パルミチン酸ドデシル、パルミチン酸テトラデシル、パルミチン酸ペンタデシル、パルミチン酸ヘキサデシル、パルミチン酸オクタデシル、パルミチン酸トリアコンチル、パルミチン酸オクタデシル、パルミチン酸ドコシル、ステアリン酸ビニル、ステアリン酸プロピル、ステアリン酸イソプロピル、ステアリン酸ブチル、ステアリン酸アミル、ステアリン酸ヘプチル、ステアリン酸オクチル、ステアリン酸テトラデシル、ステアリン酸ヘキサデシル、ステアリン酸ヘプタデシル、ステアリン酸オクタデシル、ステアリン酸ドコシル、ステアリン酸ヘキサコシル、ステアリン酸トリアコンチル、ベヘン酸ドデシル、ベヘン酸オクタデシル、ベヘン酸ドコシル、リグノセリン酸トラコシル、メリシン酸ミリシル等が挙げられる。
【００５５】
高級アルキル基を有するケトンの具体例としては、例えば、８−ペンタデカノン、９−ヘプタデカノン、１０−ノナデカノン、１１−ヘンエイコサノン、１２−トリコサノン、１４−ヘプタコサノン、１６−ヘントリアコンタノン、１８−ペンタトリアコンタノン、２２−トリテトラコンタノン、２−ペンタデカノン、２−ヘキサデカノン、２−ヘプタデカノン、２−オクタデカノン、２−ノナデカノン等が挙げられる。
【００５６】
二塩基酸エステルとしては、モノエステル、ジエステルのいずれでもよく、下記一般式（５）で表わされるものである。
【００５７】
【化９】
ＲＯＯＣ−(ＣＨ₂)ｎ−ＣＯＯＲ’・・・・・一般式（５）
（式中、Ｒ，Ｒ’は水素原子、又は炭素数１〜３０のアルキル基を表わし、Ｒ，Ｒ’は同一であっても異なっていてもよいが、同時に水素原子である場合を除く。ｎは０〜４０の整数を表わす）
上記一般式（５）で表わされる二塩基酸エステルにおいて、Ｒ，Ｒ’のアルキル基の炭素数は１〜２２が好ましく、ｎは、１〜３０が好ましく、２〜２０が更に好ましい。また融点は４０℃以上が好ましい。
【００５８】
具体的には、
コハク酸ジエステル
アジピン酸ジエステル
セバシン酸ジエステル
１−又は１８−オクタデカメチレンジカルボン酸エステル
等が挙げられる。
【００５９】
本発明で用いる有機低分子物質の多価アルコールジ脂肪酸エステルとしては、下記の一般式（６）で表わされるものが挙げられる。
【００６０】
【化１０】
CH₃(CH₂)m-₂COO(CH₂)nOOC(CH₂)m-₂CH₃・・・・・一般式（６）
（式中、ｎは２〜４０、好ましくは３〜３０、更に好ましくは４〜２２の整数である。ｍは２〜４０、好ましくは３〜３０、更に好ましくは４〜２２の整数である。）
具体的には以下のものが挙げられる。
１，３プロパンジオールジアルカン酸エステル
１，６ヘキサンジオールジアルカン酸エステル
１，１０デカンジオールジアルカン酸エステル
１，１８オクタデカンジオールジアルカン酸エステル
【００６１】
脂肪酸モノアミドの具体例としては、例えば次の一般式（７）で示されるものが挙げられる。
【００６２】
【化１１】
Ｒ¹−ＣＯＮＨ−Ｒ²・・・・・一般式（７）
（ここで、Ｒ¹は炭素数１〜２５の直鎖炭化水素鎖、Ｒ²は水素、炭素数１〜２６の直鎖炭化水素鎖、またはメチロール基であり、Ｒ¹、Ｒ²の少なくともどちらか一方が炭素数１０以上の直鎖炭化水素鎖である。）
これらの例としては、ノナンアミド、デカンアミド、ウンデカンアミド、ドデカンアミド、トリデカンアミド、テトラデカンアミド、ヘキサデカンアミド、オクタデカンアミド、イコサンアミド、ドコサンアミド、トリコサンアミド、ヘキサコサンアミド、オクタコサンアミド等を挙げることができる。
【００６３】
また、前記一般式（３）、一般式（４）で表わされる物質の例としては次のものが挙げられる。
【００６４】
【表３】

【００６５】
【表４】

【００６６】
前記の直鎖炭化水素含有化合物（Ａ）と直鎖炭化水素含有化合物（Ｂ）の他に、直鎖炭化水素含有化合物（Ｂ）の融点より１０℃以上高い融点であり、かつ直鎖炭化水素含有化合物（Ａ）より１０℃以上低い融点を持つ有機低分子物質を１種又は２種以上混合してもよい。これらは前述の直鎖炭化水素含有化合物（Ｂ）の例の中から適宜選択される。
【００６７】
感熱層に使用される樹脂母材は有機低分子物質を均一に分散保持した層を形成すると共に、最大透明時の透明度に影響を与える材料である。このため樹脂母材は透明性が良く、機械的に安定で、且つ成膜性の良い樹脂が好ましい。このような樹脂としてはポリ塩化ビニル；塩化ビニル−酢酸ビニル共重合体、塩化ビニル−酢酸ビニル−ビニルアルコール共重合体、塩化ビニル−酢酸ビニル−マレイン酸共重合体、塩化ビニル−アクリレート共重合体等の塩化ビニル系共重合体；ポリ塩化ビニリデン、塩化ビニリデン−塩化ビニル共重合体、塩化ビニリデン−アクリロニトリル共重合体等の塩化ビニリデン系共重合体；ポリエステル；ポリアミド；ポリアクリレート又はポリメタクリレート或いはアクリレート−メタクリレート共重合体；シリコーン樹脂等が挙げられる。これらの樹脂は単独で或いは２種以上混合して使用して良いことはもちろんである。
【００６８】
これらの樹脂を架橋することが好ましい。架橋した媒体は、印字と消去を繰り返しても感熱層内部の構造が変化しにくく、白濁度、透明度の低下がないなど繰り返し耐久性が向上する。架橋する場合には樹脂中にヒドロキシル基、カルボキシル基、エポキシ基などの官能基を有することが好ましい。架橋の方法としては、熱架橋、ＵＶやＥＢの照射による方法があり、イソシアネートや各種アクリル系架橋剤を添加し架橋することが好ましい。樹脂母剤のガラス転移温度は６０℃以上が好ましく、７０℃以上がもっと好ましく、１００℃未満が好ましく、９０℃未満がさらに好ましい。ガラス転移温度が高くなると画像耐熱性が向上し低くなると消去性が向上する。
【００６９】
本発明の熱可逆記録媒体の感熱層の厚さは１〜３０μｍが好ましく、２〜２０μｍが更に好ましい。４〜１５μｍが特に好ましい。記録層が厚すぎると層内での熱の分布が発生し均一に透明化することが困難となる。また、感熱層が薄すぎると白濁度が低下し、コントラストが低くなる。なお、記録層中の脂肪酸の量を増加させ、また、感熱層中の樹脂を架橋することにより、白濁度を増すことができる。なお、感熱層中の有機低分子物質と樹脂（架橋構造を有する樹脂）との割合は、重量比で２：１〜１：１６程度が好ましく、１：２〜１：８が更に好ましく、１：２〜１：５が特に好ましく、１：２〜１：４がもっと好ましく、１：２．５〜１：４がそれ以上に好ましい。樹脂の比率がこれ以下になると、有機低分子物質を樹脂中に保持した膜に形成することが困難となり、またこれ以上になると、有機低分子物質の量が少ないため、不透明化が困難になる。
【００７０】
また、感熱層上には感熱層を保護するために保護層を設けることができる。感熱層上に積層する保護層（厚さ０．１〜５μｍ）材料としては、シリコーン系ゴム、シリコーン樹脂（特開昭６３−２２１０８７号公報に記載）、ポリシロキサングラフトポリマー（特開昭６３−３１７３８５号公報に記載）や紫外線硬化樹脂又は電子線硬化樹脂（特開平０２−５６６号公報に記載）等が挙げられる。これらの中には、有機若しくは無機のフィラーを含有することができる。
【００７１】
更にまた、保護層形成液の溶剤やモノマー成分等から感熱層を保護するために、保護層と感熱層との間に中間層を設けることができる（特開平１−１３３７８１号公報に記載）。中間層の材料としては感熱層中の樹脂母材として挙げたものの他に下記のような熱硬化性樹脂、熱可塑性樹脂、ＵＶ硬化樹脂、ＥＢ硬化樹脂が使用可能である。即ち、ポリエチレン、ポリプロピレン、ポリスチレン、ポリビニルアルコール、ポリビニルブチラール、ポリウレタン、飽和ポリエステル、不飽和ポリエステル、エポキシ樹脂、フェノール樹脂、ポリカーボネート、ポリアミド等が挙げられる。中間層の厚さは０．１〜２μｍくらいが好ましい。これ以下になると、保護効果が下がり、これ以上になると熱感度が低下する。
【００７２】
本発明の上記課題は、支持体上に、樹脂母材及び樹脂母材中に分散された有機低分子物質を主成分とし、温度に依存して透明度が可逆的に変化する感熱層を設けた熱可逆記録媒体の製造方法において、有機低分子物質の少なくとも一部として融点１３０℃以上の有機低分子物質を用い、樹脂溶液中に１種以上の有機低分子物質を固体状態で分散した分散液を支持体上に塗布し加熱乾燥させ、該加熱乾燥時に分散された有機低分子物質が分散溶媒に溶解し感熱層を形成することを特徴とする熱可逆記録媒体の製造方法によって達成される。
【００７３】
用いられる有機低分子物質は、融点が３０℃以上異なるものを２種以上混合して用いることが好ましい。有機低分子物質は通常融点が高くなるにつれ、通常の溶剤には常温では溶解しにくくなってくる。特に融点が１３０℃以上となると、その傾向は顕著になる。これらの溶剤に溶解しにくい有機低分子物質を分散して用い、塗膜の加熱乾燥時に溶解させることにより、常温で溶媒に溶解させて塗膜を形成する今までと同様の構造（樹脂中に有機低分子物質が球状の微粒子で分散されている）が得られ、また、有機低分子物質を上記のように２種類以上用いた場合には、透明化温度範囲が広く、また透明状態と不透明状態とのコントラストが大きく、透明状態と不透明状態を繰り返し生じさせるための温度コントロールが容易な熱可逆記録媒体を得ることができる。
【００７４】
ここで用いられる溶媒は２種以上混合してもよく、溶媒の少なくとも１種として沸点の高い溶媒、特に沸点が１００℃以上の溶媒を用いることが好ましく、それにより透明状態と不透明状態とのコントラストが更に大きな熱可逆記録媒体を得ることができる。
【００７５】
更に、混合液における沸点の高い溶媒の含有量としては、混合液における全溶媒の１０重量％以上が特に好ましく、それにより樹脂マトリックス形状又は２種類以上の有機低分子物質が共存する有機低分子物質ドメイン形状が球形、楕円形又は丸みを帯びた形状となり、これによりコントラストの大きな透明状態と不透明状態とを多数回にわたって繰り返し生じさせることのできる熱可逆記録媒体を得ることができる。
【００７６】
上記のような熱可逆記録媒体の製造方法が適用される好ましい場合は、上記の分散液中の有機低分子物質として、混合液を支持体上に塗布し乾燥させる際の乾燥温度において分散液溶媒に溶解する有機低分子物質を用いる場合である。特に分散液溶媒に０．５％以上溶解する有機低分子物質を用いることが好ましい。また、常温において、分散液溶媒に対する分散液中に分散された有機低分子物質の溶解度は０．５％未満であることが好ましい。有機低分子物質の平均分散粒径は２０μｍ以下が好ましく、１０μｍ以下が更に好ましく、５μｍ以下が特に好ましい。
【００７７】
このような有機低分子物質を用いることにより、乾燥時に有機低分子物質が一旦溶媒に溶解し、相分離過程を経て分散液中の２種類以上の有機低分子物質が共存する有機低分子物質ドメインが形成される。
【００７８】
本発明の上記課題は、支持体上に、樹脂母材及び樹脂母材中に分散された有機低分子物質を主成分とし、温度に依存して透明度が可逆的に変化する感熱層を設けた熱可逆記録媒体の製造方法において、有機低分子物質の少なくとも一部として融点１３０℃以上の有機低分子物質を用い、樹脂溶液中に２種以上の有機低分子物質を固体状態で分散した分散液を支持体上に塗布し、感熱層中の一番高い融点をもつ有機低分子物質の融点より低い温度で加熱乾燥させて感熱層を形成し、次いで、感熱層中のすべての有機低分子物質の融点以上の温度で感熱層を加熱することを特徴とする熱可逆記録媒体の製造方法によって達成される。用いられる有機低分子物質は、融点が３０℃以上異なるものを２種以上混合して用いることが好ましい。
【００７９】
この有機低分子物質分散液を支持体上に塗布し乾燥させて可逆性感熱記録層を形成し、次いで、有機低分子物質の融点以上の温度で可逆性感熱記録層に加熱処理を施すことにより、透明化温度範囲が広く、また透明状態と不透明状態とのコントラストが大きく、透明状態と不透明状態を繰り返し生じさせるための温度コントロールが容易な熱可逆記録媒体を得ることができる。
これは可逆性感熱記録層に加熱処理を施すことによって、可逆性感熱記録層における樹脂マトリックス中にそれぞれ単独で分散している２種類以上の有機低分子物質が溶融し、熱膨張し、また、樹脂が軟化することにより合一して２種類以上の有機低分子物質が共存する有機低分子物質ドメインが形成されることによるものである。
【００８０】
また、可逆性感熱記録層に有機低分子物質の融点以上の温度で加熱処理を施すことによって、樹脂マトリックス形状又は２種類以上の有機低分子物質が共存する有機低分子物質ドメイン形状が球形、楕円形又は丸みを帯びた形状となり、これによりコントラストの大きな透明状態と不透明状態とを多数回にわたって繰り返し生じさせることのできる可逆性感熱記録材料が得られる。球形、楕円形又は丸みを帯びている樹脂マトリックス形状又は有機低分子物質ドメイン形状の個数は全樹脂マトリックス個数又は全有機低分子物質ドメイン個数の１０％以上であることが特に好ましい。これらの製造方法において、有機低分子物質を２種以上用いる場合、例えば１種が分散で用いられ、１種が常温でも溶媒に溶解されて用いられていてもよい。
【００８１】
また、可逆性感熱層の他に着色層を設けその上に可逆的感熱層を有するものが、可逆的可視像を目視し易くするために好ましい。この場合、着色層を可視光に対する反射率の異なる２種以上の部位からなるものとすることができる。
【００８２】
上記の３条件を満足する可逆表示可能な感熱層と情報記憶部の両方を同一のカードに設けることにより、情報記憶部に記憶された情報の一部を感熱層に表示することにより、カード所有者等は特別な装置がなくてもカードを見るだけで情報を確認することができ、利便性が向上する。情報記憶部は必要な情報を記憶できるものなら何でもよいが、磁気記録、ＩＣ、光メモリが好ましい。磁気記録層としては通常用いられる酸化鉄、バリウムフェライト等と塩ビ系やウレタン系或いはナイロン系樹脂等を用い、支持体に塗工形成されるか、または蒸着、スパッタリング等の方法により樹脂を用いず形成される。磁気記録部は支持体の感熱層の反対面に設けてもよいし、支持体と感熱層の間、感熱層上の一部に設けてもよい。また、表示に用いる可逆感熱材料をバーコード、２次元コード等により記憶部に用いてもよい。これらの中では磁気記録、ＩＣが更に好ましい。
【００８３】
本発明の熱可逆記録媒体では、支持体の感熱層形成面の反対面に接着剤層または粘着剤層を設けて熱可逆記録ラベルとすることができる。接着剤層または粘着剤層の材料は一般的に使われているものが使用可能である。具体例としては、ユリア樹脂、メラミン樹脂、フェノール樹脂、エポキシ樹脂、酢ビ系樹脂、酢酸ビニル−アクリル系共重合体、エチレン−酢酸ビニル共重合体、アクリル系樹脂、ポリビニルエーテル系樹脂、塩化ビニル−酢酸ビニル系共重合体、ポリスチレン系樹脂、ポリエステル系樹脂、ポリウレタン系樹脂、ポリアミド系樹脂、塩素化ポリオレフィン系樹脂、ポリビニルブチラール系樹脂、アクリル酸エステル系共重合体、メタクリル酸エステル系共重合体、天然ゴム、シアノアクリレート系樹脂、シリコン系樹脂などが挙げられるが、これらに限定されるものではない。接着剤層または粘着剤層の材料はホットメルトタイプでも良い。剥離紙を用いても良いし、無剥離紙タイプでも良い。
【００８４】
このように接着剤層または粘着剤層を設けることにより、感熱層の塗布が困難な磁気ストライプ付塩ビカードなどの厚手の基板の全面もしくは一部に貼ることができる。これにより磁気に記憶された情報の一部を表示することができる等、この媒体の利便性が向上する。このような接着剤層または粘着剤層を設けた熱可逆記録ラベルは、前述の磁気付塩ビカードだけでなく、ＩＣカードや光カードなどの厚手カードにも適用できる。
【００８５】
また、これらの熱可逆記録ラベルはフロッピーディスクやＭＤやＤＶＤ−ＲＡＭなどの記憶情報が書換可能なディスクを内蔵したディスクカートリッジ上の表示ラベルの替わりとして用いることができる。図３に熱可逆記録ラベルをＭＤのディスクカートリッジ上に貼った例を示す。さらに、ＣＤ−ＲＷなどのディスクカートリッジを用いないディスクの場合には、直接ディスクに熱可逆記録ラベルを貼ることもできる。それらの記憶内容の変更に応じて自動的に表示内容を変更するなどの用途への応用が可能である。図４に熱可逆記録ラベルをＣＤ−ＲＷ上に貼った例を示す。ＣＤ−Ｒなどの追記型ディスク上に熱可逆記録ラベルを貼って、ＣＤ−Ｒに追記した記憶情報の一部を書換え表示することも可能である。
図５は、ＡｇＩｎＳｂＴｅ系の相変化形記憶材料を用いた光情報記録媒体（ＣＤ−ＲＷ）上に熱可逆記録ラベルを形成した構成の例である。基本的な構成は、案内溝を有する基体上に第一誘電体層、光情報記憶層、第二誘電体層、反射放熱層、中間層が設けられ、基体の裏面にハードコート層を有する。さらに中間層上に熱可逆記録ラベルが貼付されている。誘電体層は必ずしも記録層の両側に設ける必要はないが、基体がポリカーボネート樹脂のように耐熱性が低い材料の場合には第一誘電体層を設けることが望ましい。
【００８６】
さらにまた、図６に示すようにビデオテープカセットの表示ラベルとして用いても良い。
厚手カード、ディスクカートリッジやディスク上に熱可逆記録機能を設ける方法としては上述の熱可逆記録ラベルを貼る方法以外に、それらの上に感熱層を直接塗布する方法やあらかじめ別の支持体上に感熱層を形成しておき、厚手カード、ディスクカートリッジやディスク上に感熱層を転写する方法などがある。転写する場合には、感熱層上にホットメルトタイプなどの接着層や粘着層を設けておいても良い。厚手カード、ディスク、ディスクカートリッジ、テープカセットなどのように剛直なものの上に熱可逆記録ラベルを貼着したり、感熱層を設ける場合には、サーマルヘッドとの接触性を向上させ画像を均一に形成するために弾力があり、クッションとなる層もしくはシートを剛直な基体とラベルもしくは感熱層の間に設けることが好ましい。
【００８７】
特に、本発明の可逆性記録媒体が、書換可能なバーコードを設けたものである場合には反射率の異なる２種以上の部位からなるものとすることが好ましい。というのは、人間が目視する場合には、例えば白濁状態の画像部と着色状態の非画像部とは光量差に加えて色調差があり、かつ、目視する角度によっては非画像部からの過度の反射光によるグレアがなくなるので可逆的可視像を目視し易くするが、一方、これを反射濃度計やバーコード読取り装置のような装置で読み取る場合には、通常、光を斜めから入射させ面に対し垂直方向にセンサーを置き読み取ることになり、これは、とりもなおさず、着色層により可視光の少なくとも一部が吸収されコントラストが低くなった結果を計測するに過ぎないためである。而して、本発明の可逆性感熱記録媒体における着色層は、可視光に対する反射率の異なる２種以上の部位からなり、かつ、その少なくとも一方の部位が可視光を吸収する層であり、他の少なくとも一部が可視光を反射する層からなるものとして、目視でも画像を認識しやすく、かつ、装置による測定でも高コントラストが得られるものすることができる。
【００８８】
可逆性（可逆的）感熱層においてバーコードを読み取るのに必要な高いコントラストを得るには、有機低分子物質の平均粒子径が０．１〜２．０μｍの範囲にあることが好ましく、より適切な白濁度になる。そして、分散された有機低分子物質の平均粒子径が大きくなればなるほど多結晶状態になり難くなり、光を散乱させる効果が小さくなって、白濁度が低下してコントラストが低くなり、逆に、分散された有機低分子物質の平均粒子径が小さくなればなるほど結晶の成長において分散されたマトリックス中で多結晶状態を形成しにくくなり、この場合も白濁度が低下してコントラストが低くなるためと考えられる。さらに、バーコードを読み取る関係から、有機低分子物質の粒子の平均粒子径がバーコードを読み取る際の光源の波長の１／８から２倍までの範囲にあるとき、バーコードの読み取り時のコントラストがさらに向上する。こうした現象が何故生じるかはいまだに明らかにされていないが、大よそ次のように推察されている。即ち、白濁度つまり光の散乱度は有機低分子物質粒子中の結晶の大きさで決まると考えられ、さらにこの結晶の大きさは有機低分子物質粒子の大きさで決まってくると考えられる。これは、有低分子物質粒子の大きさにより、樹脂母材とその樹脂母材中に分散されている有機低分子物質との界面の面積が決まり、この界面の面積から樹脂母材と有機低分子物質との相互作用の強さが決まり、その相互作用の強さが粒子中の結晶の大きさに影響を与えるためと推測されている。また、ある波長の光を一番散乱しやすい結晶の大きさがあり、これは個々の材料によって異なるが、光の波長より小さい結晶がその波長の光を散乱しやすい。つまり、有機低分子物質の平均粒子径がバーコードを読み取る光の波長の１／８から２倍までの範囲にあるとき白濁状態の有機低分子物質粒子中の多結晶の個々の結晶の大きさがその波長の光を最も散乱しやすい大きさになっているものと考えられている。前記の平均粒子径が読み取り光源の波長の１／８未満となると、散乱効果が減少し、白濁度が下がり、コントラストが減少し、逆に、２倍を越えると樹脂母材と有機低分子物質の界面の表面積が減少し、樹脂母材と有機低分子物質との相互作用が減少し、有機低分子物質粒子中の結晶の制御がしにくくなると考えられており、白濁度が下がり、コントラストが減少する。なお、有機低分子物質の粒径を制御する方法としては貧溶媒の混入、記録層形成液塗工時の加熱乾燥の制御、分散性を制御するための界面活性剤の添加等が考えられるがこれらに限定されるものではない。
【００８９】
ところで、従来バーコードを読み取るための光源の波長は６００ｎｍ以上と規定され（ＪＩＳ Ｂ９５５０）、通常６００ｎｍから１０００ｎｍの範囲の波長の光源が用いられている。具体的にはＬＥＤ（６６０ｎｍ及び９４０ｎｍの波長のものが良く用いられる）、レーザー（Ｈｅ−Ｎｅレーザーで６００ｎｍ、半導体レーザーで６８０ｎｍ、７８０ｎｍ、及び９６０ｎｍが良く用いられる）が挙げられる。
【００９０】
本発明の可逆性記録媒体におけるバーコード表示体によれば、上記したような６６０ｎｍ以上の波長の光源を用いてバーコードを読み取ることは勿論可能であるが、より短い波長の光源を用いることもでき、むしろ短い波長の光源を用いた方がより高いコントラストが得られる。例えば、４００〜６００ｎｍの光を用いれば、６００ｎｍ〜１００００ｎｍの光に比べ、コントラストは最大で２倍近くになる。これは波長の短い光の方が有機低分子物質に対する屈折率が大きくなり、光の散乱が増え、そのため白濁度が向上するためであると考えられる。
【００９１】
なお、ここでいう「バーコード」とは、光の強弱や波長の変化等の光学的変化を可視光の波長域であってもなくても情報として認識しうるものであればよく、従って、二次元バーコード、ＯＣＲ、カルラコードに代表される他の光学的認識パターン表示体をも包含する。
【００９２】
例えば本発明の可逆性感熱記録媒体は図７ａに示されるように、支持体（１１）上に、可逆性感熱記録層（１３）、保護層（１４）を設けてなるフィルム、図７ｂに示されるように、支持体（１１）上に、アルミ反射層（１２）、可逆性感熱記録層（１３）、保護層（１４）を設けてなるフィルム、図７ｃに示されるように、支持体（１１）上に、アルミ反射層（１２）、可逆性感熱記録層（１３）、保護層（１４）を設け支持体（１１）の裏面に磁気記録層（１６）を設けてなるフィルム、を図８に示されるように、印刷表示部（２３）を有するカード（２１）に加工した形であることができる。
【００９３】
さらに、例えば図９ａに示されるように、支持体（１１）上に、アルミ反射層（１２）、可逆性感熱記録層（１３）、保護層（１４）を設けてなるフィルムをカード状に加工し、ＩＣチップを納める窪み部（２３）を形成するとともにカード状に加工した形であることができる。この例においては、カード状の可逆性感熱記録媒体に書き換え記録部（２４）がラベル加工されるとともに、可逆性感熱記録媒体の裏面側には所定箇所にＩＣチップ埋め込み用窪み部（２３）が形成されており、この窪み部（２３）に、図９ｂに示されるようなウェハ（２３１）が組込まれて固定される。ウェハ（２３１）は、ウェハ基板（２３２）上に集積回路（２３３）が設けられると共に、この集積回路（２３３）に電気的に接続されている複数の接触端子（２３４）がウェハ基板（２３２）に設けられる。この接触端子（２３４）はウェハ基板（２３２）の裏面側に露出しており、専用のプリンタ（リーダライタ）がこの接触端子（２３４）に電気的に接触して所定の情報を読み出したり書き換えたりできるように構成されている。この可逆的感熱記録カードの機能例を、図１０を参照しつつ説明する。
【００９４】
図１０（ａ）は、集積回路（２３３）を示す概略の構成ブロック図であり、（ｂ）はＲＡＭの記憶データの１例を示す構成ブロック図である。集積回路（２３３）は、例えばＬＳＩで構成されており、その中には制御動作を所定の手順で実行することのできるＣＰＵ（２３５）と、ＣＰＵ（２３５）の動作プログラムデータを格納するＲＯＭ（２３６）と、必要なデータの書き込み及び読み出しができるＲＡＭ（２３７）を含む。さらに集積回路（２３３）は、入力信号を受けてＣＰＵ（２３５）に入力データを与えるとともにＣＰＵ（２３５）からの出力信号を受けて外部に出力する入出力インターフェース（２３８）と、図示していないが、パワーオンリセット回路、クロック発生回路、パルス分周回路（割込パルス発生回路）、アドレスデコーダ回路とを含む。ＣＰＵ（２３５）は、パルス分周回路から定期的に与えられる割込パルスに応じて、割込制御ルーチンの動作を実行することが可能となる。また、アドレスデコード回路はＣＰＵ（２３５）からのアドレスデータをデコードし、ＲＯＭ（２３６）、ＲＡＭ（２３７）、入出力インターフェース（２３８）にそれぞれ信号を与える。入出力インターフェース（２３８）には、複数（図中では８個）の接触端子（２３４）が接続されており、前記の専用プリンタ（リーダライタ）からの所定データがこの接触端子（２３４）から入出力インターフェース（２３８）を介してＣＰＵ（２３５）に入力される。ＣＰＵ（２３５）は、入力信号に応答して、かつＲＯＭ（２３６）内に格納されたプログラムデータに従って、各動作を行い、かつ、所定のデータ、信号を入出力インターフェース（２３８）を介してカードリーダライタに出力する。
【００９５】
図１０（ｂ）に示されるように、ＲＡＭ（２３７）は複数の記憶領域（２３９ａ）〜（２３９ｇ）を含む。例えば領域（２３９ａ）にはカード番号が記憶され、（２３９ｂ）には例えばカード所有者の氏名、住所、電話番号等のＩＤデータが記憶され、領域（２３９ｃ）には例えば所有者の使用しうる残存有価価値又は有価物に相当する情報が記憶され、領域（２３９ｄ）（２３９ｅ）（２３９ｆ）及び（２３９ｇ）には使用済の有価価値又は有価物に相当する情報が記憶される。
【００９６】
上記の熱可逆記録媒体の画像の記録と消去の方法と装置について以下に述べる。画像の記録はサーマルヘッド、レーザ等、媒体を画像上に部分的に加熱可能である画像記録手段が用いられる。画像の消去は、ホットスタンプ、セラミックヒータ、ヒートローラ、熱風等や、サーマルヘッド、レーザ等の画像消去手段が用いられる。この中ではセラミックヒータが好ましく用いられる。セラミックヒータを用いることにより、装置が小型化でき、かつ安定した消去状態が得られ、コントラストのよい画像が得られる。セラミックヒータの設定温度は１１０℃以上が好ましく、１１２℃以上が更に好ましく、１１５℃以上が特に好ましい。
【００９７】
また、サーマルヘッドを用いることにより、更に小型化が可能となり、また、消費電力を低減することが可能であり、バッテリー駆動のハンディタイプの装置も可能となる。記録用と消去用を兼ねて一つのサーマルヘッドとすれば、更に小型化が可能となる。一つのサーマルヘッドで記録と消去を行なう場合、一度前の画像を全部消去した後、あらためて新しい画像を記録してもよいし、画像毎にエネルギーを変えて一度に前の画像を消去し、新しい画像を記録していくオーバーライト方式も可能である。オーバーライト方式では記録と消去を合わせた時間が少なくなり、記録のスピードアップにつながる。
感熱層と情報記憶部を有するカードを用いる場合、上記の装置には情報記憶部の記憶を読み取る手段と書き換える手段も含まれる。
【００９８】
図１１には、本発明の熱可逆性記録装置の具体例を示す。
図１１ａは、本発明により画像の消去をセラミックヒータで、画像の形成をサーマルヘッドでそれぞれ行う場合の装置の概略例を示す。図１１ａの熱可逆性記録装置においては、最初、記録媒体の磁気記録層に記憶された情報を磁気ヘッドで読み取り、つぎにセラミックヒータで可逆性感熱層に記録された画像を加熱消去し、さらに、磁気ヘッドで読み取られた情報をもとにして、処理された新たな情報がサーマルヘッドにより、逆性感熱層に記録される。その後、磁気記録層の情報も新たな情報に書き替えられる。
【００９９】
すなわち、図１１ａの熱可逆性記録装置においては、感熱層の反対側に磁気記録層を設けた熱可逆性記録媒体（１）は往復の矢印で図示されている搬送路に沿って搬送され、或いは搬送路に沿って装置内を逆方向に搬送される。熱可逆性記録媒体（１）は、磁気ヘッド（３４）と搬送ローラ（３１）間で磁気記録層に磁気記録或いは記録消去され、セラミックヒータ（３８）と搬送ローラ（４０）間で像消去のため加熱処理され、サーマルヘッド（５３）及び搬送ローラ（４７）間で像形成され、その後、装置外に搬出される。先に説明したように、セラミックヒータ（３８）の設定温度は１１０℃以上が好ましく、１１２℃以上が更に好ましく、１１５℃以上が特に好ましい。ただし磁気記録の書きかえはセラッミックヒータによる画像消去の前であっても跡であってもよい。また、所望により、セラミックヒータ（３８）と搬送ローラ（４０）間を通過後、又はサーマルヘッド（５３）及び搬送ローラ（４７）間を通過後、搬送路を逆方向に搬送され、セラミックヒータ（３８）よる再度の熱処理、サーマルヘッド（５３）による再度の印字処理を施すことができる。
【０１００】
図１１ｂの熱可逆性記録装置においては、出入口（３０）から挿入された熱可逆性記録媒体（１）は一点破線で図示されている搬送路（５０）に沿って進行し、或いは搬送路（５０）に沿って装置内を逆方向に進行する。出入口（３０）から挿入された熱可逆性記録媒体（１）は、搬送ローラ（３１）及びガイドローラ（３２）により記録装置内を搬送され、搬送路（５０）の所定位置に到達するとセンサ（３３）により制御手段（３４ｃ）を介してその存在を認識され、磁気ヘッド（３４）とプラテンローラ（３５）間で磁気記録層に磁気記録或いは記録消去され、ガイドローラ（３６）及び搬送ローラ（３７）間を通過し、ガイドローラ（３９）及び搬送ローラ（４０）間を通過し、センサ（４３）により、セラミックヒータ制御手段（３８ｃ）を介してその存在を認識して作動するセラミックヒータ（３８）とプラテンローラ（４４）間で像消去のため加熱処理され、搬送ローラ（４５）（４６）（４７）により搬送路（５０）内を搬送され、所定位置にてセンサ（５１）により、サーマルヘッド制御手段（５３ｃ）を介してその存在を認識して作動するサーマルヘッド（５３）及びプラテンローラ（５２）間で像形成され、搬送路（５６ａ）から搬送ローラ（５９）及びガイドローラ（６０）により出口（６１）を経て装置外に搬出される。ここで、セラミックヒータ（３８）の設定温度は、先に説明したように、１１０℃以上が好ましく、１１２℃以上が更に好ましく、１１５℃以上が特に好ましい。
【０１０１】
また、所望により、搬送路切換手段（５５ａ）を切り替えることにより搬送路（５６ｂ）に導き、熱可逆性記録媒体（１）の押圧により入力するリミットスイッチ（５７ａ）の作動より逆方向に動く搬送ベルト（５８）によって、熱可逆性記録媒体（１）を再度、サーマルヘッド（５３）及びプラテンローラ（５２）間で熱処理した後、搬送路切換手段（５５ｂ）を切り替えることにより通じる搬送路（４９ｂ）、リミットスイッチ（５７ｂ）、搬送ベルト（４８）を介して順方向に搬送し、搬送路（５６ａ）から搬送ローラ（５９）及びガイドローラ（６０）により出口（６１）を経て装置外に搬出することができる。さらに、このような分岐した搬送路及び搬送切換手段は、セラミックヒータ（３８）の両側に設けることもでき、その場合にはセンサ（４３ａ）をプラテンローラ（４４）と搬送ローラ（４５）の間に設けることが望ましい。
【０１０２】
【実施例】
以下、本発明を実施例により更に具体的に説明する。なお、実施例中の「部」は重量部を表わす。
実施例１
約５０μｍ厚の透明なポリエステルフィルム（東レ社製、ルミラーＴ−６０）上に、

よりなる溶液を塗布し、加熱乾燥して約１２μｍ厚の感熱層を設けた。その上に、
ウレタンアクリレート系紫外線硬化性樹脂の １０部
７５％酢酸ブチル溶液
（大日本インキ化学工業社製、ユニディック Ｃ７−１５７）
イソプロピルアルコール １０部
よりなる溶液をワイヤーバーで塗布し、加熱乾燥後、８０ｗ／ｃｍの高圧水銀灯で紫外線を照射し、硬化させ、約３μｍ厚のオーバーコート層を設け、熱可逆記録媒体を作製した。
【０１０３】
実施例２
大日本インキ工業社製磁気原反（メモリディック ＤＳ−１７１１−１０４０：１８８μｍ厚の透明ＰＥＴフィルム上に磁気記録層及びセルフクリーニング層を塗工したもの）のＰＥＴフィルム側に約４００ÅのＡｌを真空蒸着して光反射層を設けた。その上に、
塩化ビニル−酢酸ビニル−リン酸エステル共重合体 １０部
（電気化学工業社製、デンカビニール♯１０００Ｐ）
メチルエチルケトン ４５部
トルエン ４５部
よりなる溶液を塗布、加熱乾燥し、約０．５μｍ厚の接着層を設けた。更にその上に、実施例１と同様に感熱層及びオーバーコート層を設け、熱可逆記録媒体を作製した。
【０１０４】
実施例３
感熱層の塗工溶液を下記のとおり変更する以外は、実施例１と同様にして熱可逆記録媒体を作製した。

【０１０５】
実施例４
感熱層の塗工溶液を下記のとおり変更する以外は、実施例１と同様にして熱可逆記録媒体を作製した。

【０１０６】
実施例５
感熱層の塗工溶液を下記のとおり変更する以外は、実施例１と同様にして熱可逆記録媒体を作製した。

【０１０７】
実施例６
ガラスビン中に、
塩化ビニル−酢酸ビニル共重合体 ６部
（ユニオンカーバイト社製、ＶＹＨＨ）
テトラヒドロフラン ３３部
エチルセロソルブ ８部
よるなる溶液を入れ、更に、
ＣＨ₃(ＣＨ₂)₁₇ＮＨＣＯＮＨ(ＣＨ₂)₂ＣＯＯＨ ３部
を加え、更にガラスビン中に直径約２ｍｍのセラミックビーズを入れ、ペイントシェーカー（浅田鉄工（株）製）を用い、約１８時間分散し、粒径約１０μｍの分散液（Ａ）を作製した。
次に、
ベヘン酸（ＳＩＧＭＡ社製試薬、純度９９％） ７部
塩化ビニル−酢酸ビニル共重合体 ３２部
（ユニオンカーバイト社製、ＶＹＨＨ）
テトラヒドロフラン １２０部
エチルセロソルブ ３２部
からなる溶液を作製し、この溶液１９１に対し、分散液（Ａ）５０の比率で混合し、感熱層用の塗工液を作製した。
この感熱層用の塗工液を用いる以外は実施例１と同様にして熱可逆記録媒体を作製した。
【０１０８】
比較例１
感熱層の塗工溶液を下記のとおり変更する以外は、実施例１と同様にして熱可逆記録媒体を作製した。
ベヘン酸（ＳＩＧＭＡ社製試薬、純度９９％） ５部
エイコサン二酸（岡村製油社製、ＳＬ−２０−９０） ５部
塩化ビニル−酢酸ビニル共重合体 ３８部
（ユニオンカーバイト社製、ＶＹＨＨ）
テトラヒドロフラン ２１０部
トルエン ２０部
【０１０９】
比較例２
約５０μｍ厚の透明なポリエステルフィルム（東レ社製、ルミラーＴ−６０）上に、
ベヘン酸（ＳＩＧＭＡ社製試薬、純度９９％） ６部
エイコサン二酸（岡村製油社製、ＳＬ−２０−９０） １部
１，４−シスシクロヘキサンジカルボン酸 ０．７部
（東京化成社製、試薬）
１，４−トランスシクロヘキサンジカルボン酸 ０．７部
（東京化成社製、試薬）
塩化ビニル−酢酸ビニル−ビニルアルコール共重合体 ２４部
（積水化学工業社製、エスレックＡ）
イソシアナート ２．４部
（旭化成社製硬化剤、デュラネート２４Ａ−１００）
トリエチレンジアミン（東京化成社製試薬、硬化促進剤） ０．２４部
テトラヒドロフラン １３６部
トルエン １４部
よりなる溶液を塗布した後、１３０℃、３分間加熱し、乾燥、硬化して約１２μｍ厚の感熱層を設けた。その上に、実施例１と同様にオーバーコート層を設け、熱可逆記録媒体を作製した。
【０１１０】
比較例３
感熱層の塗工溶液を下記のとおり変更する以外は、比較例２と同様にして熱可逆記録媒体を作製した。
ベヘン酸（ＳＩＧＭＡ社製試薬、純度９９％） ９部
１，４−シスシクロヘキサンジカルボン酸 ０．５部
（東京化成社製、試薬）
１，４−トランスシクロヘキサンジカルボン酸 ０．５部
（東京化成社製、試薬）
塩化ビニル−酢酸ビニル−ビニルアルコール共重合体 ３０部
（積水化学工業社製、エスレックＡ）
イソシアナート ３部
（旭化成社製硬化剤、デュラネート２４Ａ−１００）
トリエチレンジアミン（東京化成社製試薬、硬化促進剤） ０．３部
テトラヒドロフラン １７０部
トルエン １７部
【０１１１】
比較例４
感熱層の塗工溶液を下記のとおり変更する以外は、実施例１と同様にして熱可逆記録媒体を作製した。
１２−トリコサノン（東京化成社製、試薬） ３３部
１４−ヘプタコサノン（東京化成社製、試薬） １１部
デオキシコール酸（東京化成社製、試薬） ４部
塩化ビニル−酢酸ビニル共重合体 １００部
（ユニオンカーバイト社製、ＶＹＨＨ）
テトラヒドロフラン ５５０部
トルエン ５５部
【０１１２】
比較例５
感熱層の塗工溶液を下記のとおり変更する以外は、実施例１と同様にして熱可逆記録媒体を作製した。
リグノセリン酸エチル（東京化成社製、試薬） ３０部
デオキシコール酸（東京化成社製、試薬） １０部
塩化ビニル−酢酸ビニル共重合体 １００部
（ユニオンカーバイト社製、ＶＹＨＨ）
テトラヒドロフラン ５７０部
トルエン ５７部
【０１１３】
実施例７
ガラスビン中に、
塩化ビニル系共重合体 ５部
（日本ゼオン社製、ＭＲ−１１０）
テトラヒドロフラン ４２部
よるなる溶液を入れ、更に、
ＨＯＯＣ(ＣＨ₂)₅ＮＨＣＯ(ＣＨ₂)₄ＣＯＮＨ(ＣＨ₂)₅ＣＯＯＨ ３部
を加え、更にガラスビン中に直径約２ｍｍのセラミックビーズを入れ、ペイントシェーカー（浅田鉄工（株）製）を用い、約４８時間分散し、粒径約２μｍの分散液（Ｂ）を作製した。
次に、
ベヘン酸（ミヨシ油脂社製、Ｂ−９５） ７部
エイコサン二酸（岡村製油社製、ＳＬ−２０−９０） １．５部
塩化ビニル系共重合体 ２４部
（日本ゼオン社製、ＭＲ−１１０）
テトラヒドロフラン １２５部
オルトキシレン ２７部
からなる溶液を作製し、この溶液１８４．５部に対し、分散液（Ｂ）２５部の比率で混合し、更にイソシアネート化合物（日本ポリウレタン社製、コロネートＨＫ）を２．５部混合することにより、感熱層用の塗工液を作製した。
実施例２と同様にして作製した光反射層と接着層付きの磁気原反の接着層の上に、この感熱層用塗工液を塗布し、約１３０℃で３分間、加熱乾燥して約１０μｍの感熱層を設け、さらに約６０℃の環境下に２４時間放置し、記録層中のイソシアネートと塩化ビニル系共重合体を架橋させた。
次に、感熱層上に実施例１と同様にして、オーバーコート層を設けた後、約１５０℃で３０秒間加熱し、感熱層中の有機低分子物質を相互に溶融させ、熱可逆記録媒体を作製した。
【０１１４】
実施例８
実施例７のベヘン酸７部を、
１２−トリコサノン（東京化成社製、試薬） ５．２部
１４−ヘプタコサノン（東京化成社製、試薬） １．８部
とする以外は、実施例７と同様にして熱可逆記録媒体を作製した。
【０１１５】
実施例９
分散液（Ｂ）のＨＯＯＣ(ＣＨ₂)₅ＮＨＣＯ(ＣＨ₂)₄ＣＯＮＨ(ＣＨ₂)₅ＣＯＯＨを、ＨＯＯＣ(ＣＨ₂)₃ＮＨＣＯ(ＣＨ₂)₁₂ＣＯＮＨ(ＣＨ₂)₃ＣＯＯＨとし、オーバーコート層を設けた後の加熱温度を１６０℃とする以外は、実施例７と同様にして熱可逆記録媒体を作製した。
【０１１６】
実施例１０
分散液（Ｂ）のＨＯＯＣ(ＣＨ₂)₅ＮＨＣＯ(ＣＨ₂)₄ＣＯＮＨ(ＣＨ₂)₅ＣＯＯＨを、ＨＯＯＣ(ＣＨ₂)₅ＮＨＣＯ(ＣＨ₂)₂ＣＯＮＨ(ＣＨ₂)₅ＣＯＯＨとし、オーバーコート層を設けた後の加熱温度を１７５℃とする以外は、実施例７と同様にして熱可逆記録媒体を作製した。
【０１１７】
実施例１１
実施例１で作製した熱可逆記録媒体の支持体の感熱層面の裏面に、約５μｍのアクリル系粘着剤層を設け、熱可逆記録ラベルを作製した。このラベルを図４のようにドーナッツ状にして図５のようにＣＤ−ＲＷ上に貼り合わせて可逆表示機能付きの光情報記録媒体を作製した。
上記のように作製した光情報記録媒体を用い、ＣＤ−ＲＷドライブ（（株）リコー製 ＭＰ６２００Ｓ）で記憶した情報の一部（年月日、時刻など）を、記録手段（サーマルヘッド）と消去手段（セラミックヒーター）を有する記録装置を用いて、サーマルヘッドの記録エネルギーをそれぞれの媒体の記録温度の変化に合わせて調整して感熱層へ表示記録し、可視化した。また、該ドライブを用い、光情報記録媒体の記憶層の情報を書き換え、記録装置により消去手段を用い、先の記録を消去し新たにサーマルヘッドで、書き換えた情報を感熱層に書き換え、表示記録した。さらに、この表示記録の書き換えを１００回繰り返したが、記録および消去は可能であった。
【０１１８】
実施例１２
実施例１１の熱可逆記録ラベルを図３に示すようにミニディスク（ＭＤ）ディスクカートリッジ上に貼り付けた。ＭＤに記憶された情報の一部（年月日、曲名など）を、記録手段（サーマルヘッド）と消去手段（セラミックヒーター）を有する記録装置を用いて、サーマルヘッドの記録エネルギーをそれぞれの媒体の記録温度の変化に合わせて調整して感熱層へ表示記録し、可視化した。さらに、この表示記録の書き換えを１００回繰り返したが、記録および消去は可能であった。
【０１１９】
比較例６
感熱層の塗工溶液を下記のとおり変更する以外は、実施例２と同様にして熱可逆記録媒体を作製した。ここで形成された感熱層は、白色の粒子が目立ち均一性の悪いものであった。
ベヘン酸ベヘニル（シグマ社製、試薬） ９．５部
エチレンビスベヘン酸アミド ０．５部
（日本化成社製、スリパックスＢ）
塩化ビニル−酢酸ビニル共重合体 ３０部
（ユニオンカーバイト社製、ＶＹＨＨ）
テトラヒドロフラン １６０部
【０１２０】
次に、実施例１〜１０、比較例１〜６に係る熱可逆記録媒体を熱傾斜試験機（東洋精機製、ＨＧ−１００）を用い、加熱時間１秒、圧力約２．５ｋｇ／ｃｍ²とし、５℃間隔で温度を変え、加熱した後、常温に冷却し、実施例１、実施例３〜６、比較例１〜５の場合は加熱した部位の背面に透明ＰＥＴフィルム上に約４００Å厚でＡｌを蒸着したフィルム（東洋メタライジング（株）♯５０ メタルミー）を蒸着面側を上にして置き、実施例２、７〜１０、比較例６の場合はそのままでマクベスＲＤ９１４反射濃度計を用い、各温度に加熱した後の濃度値を測定した。その結果を図１２〜１７に示す。
この図から、最大濃度値（Ｄ_max）、平均透明濃度（Ｄ_tav）、透明化下限濃度（Ｄ_tm）、白濁上限濃度（Ｄ_s）、透明化開始濃度度（Ｄ_ta）、白濁化下限温度（Ｔ_sl）、透明化開始温度（Ｔ_ta）、透明化下限温度（Ｔ_tl）、透明化上限温度（Ｔ_tu）、透明化上限温度と白濁化下限温度の差（ΔＴ_ts）、透明化温度幅（ΔＴ_w）を読み取り、若しくは算出した。その結果を表５、７に示す。
【０１２１】
更に、下記の測定を行なった。その結果を表６、８に示す。
（１）コントラスト＝Ｄ_tav−Ｄ_min（表５、７の数値から算出）
（２）消去性
あらかじめ、媒体を透明化しておき、九州松下電器製リーダライタ（Ｒ−３０００）を用い、０℃環境下で、熱傾斜試験機で部分的に白濁化させた後、消去温度の中心近辺の最適消去温度で消去することを、５０枚行ない、画像の消去状態を目視で判定した。
○：すべて消去可能
○〜△：薄い消し残りが少し発生
△：明らかな消し残りが時々発生
×：消し残りが頻繁に発生
（３）耐熱性
あらかじめ、媒体を透明化した後、熱傾斜試験機で十分加熱し、部分的に白濁化させた媒体を６０℃、６５℃、７０℃に設定した恒温槽中に２４時間放置した後、取り出し、白濁部（白濁画像）をマクベスＲＤ９１４反射濃度計を用い濃度値を測定した。
（４）最適印字エネルギー
あらかじめ、媒体を透明化した後、沖電気製（ＲＣ−３０／Ｍ２０）を用い、印字エネルギーを上げていき、十分に白濁化可能になり始めるエネルギーを最適印字エネルギーとした。
（５）繰り返し耐久性−１
それぞれの媒体上に、ＲＩテスタを用い、ＯＰニス（大日本インキ社製、ニューダイキュアＧＰＯＰニス）を約２μｍ厚で形成した後、高圧水銀灯で紫外線を照射し、硬化させた。この媒体を沖電気製リーダライタ（ＲＣ−３０／Ｍ２０）を用い、それぞれ最適エネルギーで印字し、最適消去温度で消去した。印字と消去を５０回繰り返した後、表面のＯＰニスのキズの状態を目視で判定した。
○：ほとんど発生なし
△：少し発生
△〜×：やや悪い
×：悪い
（６）繰り返し耐久性−２
「（５）繰り返し耐久性−１」で得られたそれぞれの媒体の最適印字エネルギーの４０％増しのエネルギーで印字する以外は、「（５）繰り返し耐久性−１」と同様にして、画像の印字と消去を５０回繰り返した。このように印字エネルギーを４０％増やすことにより、最適印字エネルギーで５００回繰り返した場合と同じ約１０倍の強制テストとなる。５０回目の画像の濃度をマクベスＲＤ９１４反射濃度計を用い濃度値を測定した。
ここで（２）消去性、（４）最適印字エネルギー、（５）繰り返し耐久性−１、（６）繰り返し耐久性−２の評価では、実施例１、実施例３〜６と比較例１〜５は媒体に１２５μｍのＰＥＴフィルムを両面テープで貼り合わせた後評価した。実施例２、７〜１０、比例６はそのまま評価した。
【０１２２】
【表５】

【０１２３】
【表６】

【０１２４】
【表７】

【０１２５】
【表８】

【０１２６】
【発明の効果】
以上、詳細かつ具体的な説明から明らかなように、本発明によれば、画像耐熱性を維持したまま透明化する温度幅を広げ、環境温度が変化しても十分な画像消去性ひいては十分なコントラストが得られ、かつ良好な繰り返し耐久性が得られる熱可逆性記録媒体及びこれを用いたカードが提供され、また、そのための製造方法及びこれら熱可逆性記録媒を用いるに適した画像方法及び装置が提供されるという極めて優れた効果が発揮される。
【図面の簡単な説明】
【図１】本発明に係る熱可逆記録媒体による透明度の変化を表した図である。
【図２】本発明に係る熱可逆記録媒体の透明化上限温度、白濁化下限温度、透明化開始温度、透明化温度幅を説明する図である。
【図３】熱可逆記録ラベルをＭＤのディスクカートリッジ上に貼った例を示す図である。
【図４】熱可逆記録ラベルをＣＤ−ＲＷ上に貼った例を示す図である。
【図５】ＡｇＩｎＳｂＴｅ系の相変化形記憶材料を用いた光情報記録媒体（ＣＤ−ＲＷ）上に熱可逆記録ラベルを形成した構成の例を示す図である。
【図６】ビデオテープカセットの表示ラベルを示す図である。
【図７】本発明に係る熱可逆記録媒体の層構成例を示す図である。
【図８】本発明に係る熱可逆記録媒体の１例を説明する図である。
【図９】本発明に係る熱可逆記録媒体の別の１例を説明する図である。
【図１０】本発明に係る熱可逆記録媒体の使用例を説明する図である。
【図１１】本発明に係る熱可逆記録装置の１例を説明する図である。
【図１２】本発明に係る熱可逆記録媒体例の温度−反射濃度の関係を示す図である。
【図１３】本発明に係る別の熱可逆記録媒体例の温度−反射濃度の関係を示す図である。
【図１４】比較例の熱可逆記録媒体例の温度−反射濃度の関係を示す図である。
【図１５】別の比較例の熱可逆記録媒体例の温度−反射濃度の関係を示す図である。
【図１６】本発明に係る別の熱可逆記録媒体例の温度−反射濃度の関係を示す図である。
【図１７】別の比較例の熱可逆記録媒体例の温度−反射濃度の関係を示す図である。
【符号の説明】
１ 熱可逆性記録媒体
１１ 支持体
１２ アルミニウム反射層
１３ 感可逆性記録層
１４ 保護層
１５ 透明ＰＥＴフイルム
１６ 空気層
１７ 接着層
２０ 磁気塗工層
２１ カード
２２ 書き換え記録部
２３ ＩＣチップ用窪み部
２４ 書き換え記録部のラベル加工
３０ 出入口
３１ 搬送ローラ
３２ ガイドローラ
３３ センサ
３４ 磁気ヘッド
３４ｃ 制御手段
３５ プラテンローラ
３６ ガイドローラ
３７ 搬送ローラ
３８ セラミックヒータ
３８ｃ 制御手段
３９ ガイドローラ
４０ 搬送ローラ
４３ センサ
４４ プラテンローラ
４５ 搬送ローラ
４６ 搬送ローラ
４７ 搬送ローラ
４８ 搬送ベルト
４９ａ 搬送路
４９ｂ 搬送路
５０ 搬送路
５１ センサ
５２ プラテンローラ
５３ サーマルヘッド
５３ｃ 制御手段
５４ 搬送路
５５ａ 搬送路切換手段
５５ｂ 搬送路切換手段
５６ａ 搬送路
５６ｂ 搬送路
５７ａ リミットスイッチ
５７ｂ リミットスイッチ
５８ 搬送ベルト
５９ 搬送ローラ
６０ ガイドローラ
６１ 出口
２３１ ウエハ
２３２ ウエハ基板
２３３ 集積回路
２３４ 接触端子
２３５ ＣＰＵ
２３６ ＲＯＭ
２３７ ＲＡＭ
２３８ 入出力用インターフェース
２３９ ＲＡＭ記憶領域の情報[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thermoreversible recording medium, card, label, disk cartridge, disk, and tape cassette capable of repeatedly forming and erasing an image any number of times by utilizing a reversible change in transparency depending on the temperature of the thermosensitive layer. The present invention also relates to a method for manufacturing a thermoreversible recording medium, and a recording and erasing method and apparatus.
[0002]
[Prior art]
In recent years, a thermoreversible recording medium having a thermosensitive layer that can perform temporary image display and can erase the image when it becomes unnecessary, and whose transparency changes reversibly depending on temperature, has attracted attention. A typical example is a thermoreversible recording medium in which an organic low-molecular substance such as a higher fatty acid is dispersed in a resin base material such as vinyl chloride-vinyl acetate copolymer described in JP-A-55-154198. It has been. However, these conventional thermoreversible recording media have a drawback that the temperature range showing translucency and transparency is as narrow as 2 to 4 ° C., and images can be obtained by utilizing translucency / transparency and shading / turbidity. There was difficulty in temperature control during formation. In consideration of this point, the present inventors have mixed and used higher fatty acids and aliphatic dicarboxylic acids as described in JP-A-2-1363 and JP-A-3-2089. It has been clarified that the temperature range to become transparent can be expanded to around 20 ° C. and the image can be easily erased (transparent). However, when the ambient temperature changes greatly, the heating time for erasing is In the short case it was still not enough.
[0003]
Further, as described in JP-A-4-366682, JP-A-5-294062, JP-A-6-255247, etc., a higher ketone having a lower melting point than higher fatty acids in order to improve erasability. It has also been proposed to use a mixture of a fatty acid ester and an aliphatic dicarboxylic acid or a saturated aliphatic bisamide to widen the transparent temperature range. However, although the clearing temperature range is widened and erasability is improved, the clearing temperature spreads to a low temperature because a material having a low melting point is used, and the formed cloudy image disappears in a high temperature environment. There was a drawback that it would.
[0004]
In order to improve erasability without deteriorating image heat resistance, aliphatic dicarboxylic acids described in JP-A-5-139053, JP-A-6-48024, JP-A-6-48025, etc. An alicyclic dicarboxylic acid having a melting point of about 200 ° C., which has a significantly higher melting point, and a low molecule having a steroid skeleton having a melting point close to 200 ° C. described in JP-A-8-20167 and JP-A-8-282131 It has been proposed to use a substance mixed with a low-melting low-molecular substance to shift the transparency temperature to a high temperature. However, these can also improve the erasability while maintaining the image heat resistance, but the temperature difference from the upper limit temperature of the transparency to the start temperature of the white turbidity is large, when forming a cloudy image, It requires a very large amount of energy, and has a drawback that it causes problems in repeated durability, such as the surface of the medium being damaged or white turbidity being easily lowered by repeated printing and erasing. In addition, if the energy for forming a cloudy image increases, it is necessary to increase the pulse application time of the thermal head due to power supply voltage constraints, and the recording speed becomes slower, and if the energy is increased, the life of the thermal head is shortened. For example, there is a drawback that the recording and erasing apparatus using this medium has an adverse effect. In this case, the reason why the clouding start temperature is very high is considered to be due to the use of a low molecular substance having a melting point higher than necessary.
[0005]
[Problems to be solved by the invention]
In view of the current situation, the object of the present invention is to widen the temperature range to be transparent while maintaining image heat resistance, and even if the environmental temperature changes, sufficient image erasability and thus sufficient contrast can be obtained and good. It is an object of the present invention to provide a thermoreversible recording medium capable of obtaining a high durability, an image forming method using the same, an image processing method for erasing, and an image processing apparatus therefor.
[0006]
[Means for Solving the Problems]
The problems as described above are as follows. (1) “Thermosensitive layer whose main component is a resin matrix and a low molecular weight organic substance dispersed in the resin matrix and whose transparency changes reversibly depending on temperature. In a thermoreversible recording medium having As the organic low-molecular substance, at least one of a linear hydrocarbon-containing compound (A) having at least one of an amide bond, a urea bond, and a sulfonyl bond and a carboxyl group and having a melting point of 130 ° C. or higher and 200 ° C. or lower, and the linear hydrocarbon At least one linear hydrocarbon-containing compound (B) having a melting point 30 ° C. or more lower than the melting point of the containing compound (A) and having a melting point of 40 ° C. or more and less than 130 ° C. is converted into the linear hydrocarbon-containing compound (B). The linear hydrocarbon-containing compound (A) is used by mixing at a mixing ratio of 98: 2 to 10:90, and A thermoreversible recording medium characterized by satisfying the following three conditions.
(1) Clearing upper limit temperature is 125 ° C or higher
(2) The temperature difference between the maximum transparency temperature and the minimum whitening temperature is 20 ° C or less.
(3) The thermoreversible recording medium as described in (1) above, wherein the clearing start temperature is less than 95 ° C., (2) “the clearing temperature range is 30 ° C. or more”, (3) “The thermoreversible recording medium according to the item (1) or (2), wherein the maximum transparency temperature is 130 ° C. or higher”, (4) “the maximum transparency temperature and the minimum clouding temperature” The thermoreversible recording medium according to any one of (1), (2) and (3), wherein the temperature difference is 15 ° C. or less. ", (5) “The linear hydrocarbon-containing compound (A) is a linear hydrocarbon-containing compound having an amide bond and a carboxyl group,” Items (1) to (4) The thermoreversible recording medium according to any one of (6) “The linear hydrocarbon-containing compound (A) is a material having a structure of the following general formula (1): (5) The thermoreversible recording medium according to item.
[0007]
[Chemical 3]
HOOC- (CH ₂ ) n-X- (CH ₂ ) m-Y- (CH ₂ ) n-COOH General formula (1)
(Here, 26 ≧ n ≧ 1, 26 ≧ m ≧ 1, X and Y represent CONH or NHCO, provided that X and Y do not take the same structure at the same time.) ” (7) “The linear hydrocarbon-containing compound (A) is a linear hydrocarbon-containing compound having a urea bond and a carboxyl group,” Items (1) to (4) The thermoreversible recording medium according to any one of (8) “The linear hydrocarbon-containing compound (A) is a straight-chain hydrocarbon-containing compound having a sulfonyl bond and a carboxyl group,” Items (1) to (4) The thermoreversible recording medium according to any one of (9) “The linear hydrocarbon-containing compound (A) is a material having a structure of the following general formula (2): (7) Term or (8) The thermoreversible recording medium according to Item.
[0008]
[Formula 4]
CH _Three − (CH ₂ ) n-Z- (CH ₂ ) m-COOH General formula (2)
(Where 25 ≧ n ≧ 0, 26 ≧ m ≧ 1, Z is NHCONH or SO ₂ Represents. ) ", (10) “Linear hydrocarbon having a melting point of 10 ° C. or more higher than the melting point of the linear hydrocarbon-containing compound (B) and 10 ° C. or more lower than the melting point of the linear hydrocarbon-containing compound (A) as the organic low-molecular substance The compound (C) is used as a mixture. (1) Term or (9) It is achieved by the thermoreversible recording medium according to any one of the items.
[0009]
In addition, the object of the present invention is (11) “On the support, there was provided a heat sensitive layer whose main component is a resin matrix and a low molecular weight organic substance dispersed in the resin matrix, and whose transparency changes reversibly depending on the temperature. Any one of the items (1) to (10) In the method for producing a thermoreversible recording medium, As the organic low-molecular substance, at least one of a linear hydrocarbon-containing compound (A) having at least one of an amide bond, a urea bond, and a sulfonyl bond and a carboxyl group and having a melting point of 130 ° C. or higher and 200 ° C. or lower, and the linear hydrocarbon At least one linear hydrocarbon-containing compound (B) having a melting point 30 ° C. or more lower than the melting point of the containing compound (A) and having a melting point of 40 ° C. or more and less than 130 ° C. is converted into the linear hydrocarbon-containing compound (B). The linear hydrocarbon-containing compound (A) is mixed at a mixing ratio of 98: 2 to 10:90. Used, a dispersion in which one or more organic low-molecular substances are dispersed in a solid state in a resin solution is applied onto a support, dried by heating, and the organic low-molecular substances dispersed during the heating and drying are dissolved in the dispersion solvent. And a method for producing a thermoreversible recording medium, characterized by forming a thermosensitive layer ", (12) “The solubility of the organic low molecular weight substance dispersed in the dispersion liquid with respect to the dispersion solvent at a drying temperature at which the dispersion liquid is applied to the support and dried is 0.5% or more. (11) A method for producing a thermoreversible recording medium according to the item ", (13) “At room temperature, the solubility of the low molecular weight organic substance dispersed in the dispersion in the dispersion solvent is less than 0.5%. (11) A method for producing a thermoreversible recording medium according to the item ", (14) “On the support, there was provided a heat sensitive layer whose main component is a resin matrix and a low molecular weight organic substance dispersed in the resin matrix, and whose transparency changes reversibly depending on the temperature. Any one of the items (1) to (10) In the method for producing a thermoreversible recording medium, As the organic low-molecular substance, at least one kind of linear hydrocarbon-containing compound (A) having at least one of an amide bond, urea bond, sulfonyl bond and a carboxyl group and having a melting point of 130 ° C. or higher and 200 ° C. or lower, and the linear hydrocarbon At least one linear hydrocarbon-containing compound (B) having a melting point 30 ° C. or more lower than the melting point of the containing compound (A) and having a melting point of 40 ° C. or more and less than 130 ° C. is converted into the linear hydrocarbon-containing compound (B). The linear hydrocarbon-containing compound (A) is mixed at a mixing ratio of 98: 2 to 10:90. Used, a dispersion in which two or more organic low-molecular substances are dispersed in a resin solution in a solid state is coated on a support, and the temperature is lower than the melting point of the organic low-molecular substance having the highest melting point in the heat-sensitive layer. This is achieved by “a method for producing a thermoreversible recording medium, which comprises heating and drying to form a heat-sensitive layer, and then heating the heat-sensitive layer at a temperature equal to or higher than the melting point of all the organic low-molecular substances in the heat-sensitive layer”.
[0010]
Furthermore, the object is to (15) “From the above item (1) to (10) A card having a thermoreversible recording unit and an information storage unit having a thermoreversible recording medium that satisfies any one of the conditions of the item ", (16) “The information storage unit is at least one selected from a magnetic recording layer, an IC, and an optical memory. (15) Card according to the section ", (17) “At least the thermoreversible recording portion, the support, and the magnetic recording layer, which are laminated in this order. (16) Card according to the section ", (18) “At least the item (1) to (10) A thermoreversible recording part comprising the thermoreversible recording medium according to any one of the items, a support, and an adhesive layer or a pressure-sensitive adhesive layer. (19) “Items (1) to (1) above on a cartridge containing a disk in which stored information can be rewritten”. (10) Forming a thermoreversible recording unit comprising the thermoreversible recording medium according to any one of the items (18) A disc cartridge with a reversible display, characterized in that the label according to the item is attached ", (20) “From the item (1) to the above on a disk on which stored information can be rewritten or additionally written” (10) Forming a thermoreversible recording unit comprising the thermoreversible recording medium according to any one of the items (18) A disc with a reversible display, characterized in that the label according to the item is attached ", (21) “Items (1) to (3) above on a tape cassette in which stored information can be rewritten. (10) Forming a thermoreversible recording unit comprising the thermoreversible recording medium according to any one of the items (18) This is achieved by a “tape cassette with a reversible display” characterized in that the label according to the item is attached.
[0011]
Furthermore, the object is that of the present invention. (22) “The image is formed by printing on at least one copy” (15) Term or Any one of the items (21) Card, label, disc cartridge, disc, tape cassette " (23) “From the above item (1) to (10) Term or the above (15) Term or (22) The image is recorded and erased by heating using the thermoreversible recording medium, card, label, disk cartridge with reversible display, disk with reversible display, or tape cassette with reversible display. It is characterized by Image processing method ", (24) “The image is recorded by a thermal head” (23) Image processing method according to the section ", (25) “The image is erased by a ceramic heater. Item (23) or (24) Image processing method according to the section ", (26) “The set temperature of the ceramic heater is 110 ° C. or more” (25) Image processing method according to the section ", (27) “The image is erased by a thermal head,” Item (23) or (24) Image processing described in section Method " (28) “Using the thermal head, the previously formed image is overwritten, and the image is erased and a new image is recorded. (27) And the image processing method described in the above section.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail.
The thermoreversible recording medium of the present invention utilizes the change in transparency (transparent state, cloudy opaque state) as described above. The difference between the transparent state and the cloudy opaque state is estimated as follows.
[0014]
That is, in the case of (i) transparent, the organic low molecular weight substance particles dispersed in the resin matrix and the resin matrix are in close contact with each other, and there is no void in the particle part, and light incident from one side Appears to be transparent because it transmits to the opposite side without being scattered. (Ii) In the case of cloudiness, the particles of organic low-molecular substances are composed of polycrystals composed of fine crystals of organic low-molecular substances. This is because there is a gap between the crystal interface or the particle / resin matrix, and light incident from one side is white because it is refracted, reflected, and scattered at the void / crystal interface, and the void / resin interface. ing.
[0015]
FIG. 1 explains the temperature-transparency change in one example of the thermoreversible recording medium of the present invention in an easy-to-understand manner. In FIG. 1, a resin base material and an organic low molecular substance dispersed in the resin base material are shown. The heat-sensitive layer mainly composed of ₀ It is in an opaque state at the following normal temperature.
As this is heated, the temperature T ₁ Gradually begins to become transparent from the temperature T ₂ ~ T _Three When it is heated to transparent, it becomes transparent. ₀ It remains transparent even when returned to the normal temperature below. This is the temperature T ₁ The resin begins to soften from the vicinity, and as the softening progresses, the resin shrinks, for example, to reduce the interface between the resin and the organic low molecular substance particles or the voids in the particles. ₂ ~ T _Three The organic low molecular weight material becomes semi-molten and becomes transparent by filling the remaining voids with the molten organic low molecular weight material. By cooling with the seed crystal remaining, it is crystallized at a relatively high temperature. However, since the resin follows the volume change of the particles accompanying crystallization, the resin does not form voids and the transparent state is maintained.
[0016]
T _Four When heated to the above temperature, a translucent state intermediate between maximum transparency and maximum opacity is achieved. Next, when this temperature is lowered, the first cloudy opaque state is restored without taking the transparent state again. This is the temperature T _Four After the organic low molecular weight material is completely melted as described above, it becomes supercooled and T ₀ This is probably because crystallization occurs at a slightly higher temperature, and in that case, the resin cannot follow the volume change accompanying crystallization and voids are generated.
However, the temperature-transparency change curve shown in FIG. 1 is only a representative example, and the transparency of each state may change depending on the material by changing the material.
[0017]
Clarification upper limit temperature (T _tu ), Clouding lower limit temperature (T _sl ), Temperature difference between the clearing upper limit temperature and the clouding lower limit temperature (ΔT _ts ), Transparency start temperature (T _ta ), The transparency temperature range (ΔTw) is determined as follows.
First, a white turbid thermoreversible recording medium is prepared. In order to use a transparent medium or a medium that is not sufficiently clouded, the medium is clouded in advance by pressing the medium against a sufficiently heated hot plate and heating. The heating time may be about 10 seconds to 30 seconds. In order to confirm that the heating temperature is sufficient to cause white turbidity, the heating may be performed again at a slightly higher temperature (for example, a temperature higher by 10 ° C.). If the turbidity does not change between the two, the initial heating temperature is sufficiently high to cause turbidity. If the white turbidity is higher when heated at a slightly higher temperature, the temperature is still lower at the first temperature, and the heating temperature is raised and the same can be repeated.
[0018]
Next, the white turbid recording medium is heated while changing the temperature, and the temperature at which it becomes transparent is examined. A thermal tilt tester (HG-100 manufactured by Toyo Seiki Co., Ltd.) is used for heating the recording medium. This thermal gradient tester has 5 heating blocks, each block can set the temperature individually, it is also possible to control the heating time and pressure, the medium at 5 different temperatures at once under the set conditions Can be heated. Specifically, the heating time is 1 second, and the heating pressure is about 2.5 kg / cm. ² The heating temperature is from a low temperature at which whiteness does not change even when heated to a temperature at which it becomes sufficiently cloudy at an equal temperature interval of 1 to 5 ° C. In order to prevent the medium from sticking to the heat block, a thin film of polyimide or polyamide (10 μm or less) may be placed on top. After heating as such, it is cooled to room temperature, the density of the heated part is measured using a Macbeth RD-914 reflection densitometer, and the horizontal axis is the set temperature of the thermal tilt tester as shown in FIG. Create a graph with the vertical axis as the reflection density. When the medium uses a transparent support, the density is measured by placing a sheet that absorbs light or a sheet that regularly reflects light on the back of the medium. The graph is completed by plotting the concentration values for each temperature and then connecting the plotted adjacent points with a straight line. The created graph usually has a trapezoidal shape as shown in FIG.
[0019]
These data are also affected by the thickness and material of the medium including the heat-sensitive layer and the support. If the thickness of the medium is 300 μm or less, it is not affected by the thickness, and almost the same data can be obtained, but if the thickness is more than that, the support side is scraped or peeled to make the thickness 300 μm or less, What is necessary is just to convert the thick part. The material may be anything as long as it is mainly a polymer, but in the case of metal, it is necessary to convert it.
[0020]
From this graph, the above clearing upper limit temperature and white turbidity lower limit temperature are read and calculated. First, the maximum density value (D _max ). Next, y = 0.7 × D _max And draw a plot point with higher concentration than this line. The number of plot points is preferably 5 to 20 points. If it is less, the subsequent calculation results will be uncertain. When the number of plot points is small, it is necessary to narrow the heating temperature interval in the above-described thermal gradient tester and increase the number. Among the selected plot points, the same number of each of the density values with the larger density value and those with the smaller density value are excluded, and the average density value of the remaining density values is determined as the average transparent density (D _tav ). The ratio of excluding large and small density values is 10 to 30%, preferably 15 to 25%, of the selected plot points. By excluding those having a large density value and those having a small density value, an accurate value of the transparent density of the medium can be calculated.
[0021]
Next, the lower limit of transparency (D _tm ) Is calculated by the following formula (I).
[0022]
[Expression 1]
D _tm = D _tav −0.2 × (D _tav -D _min ) ・ ・ ・ ・ ・ Formula (I)
Where D _min Is the maximum cloudiness concentration, and when the temperature is raised and the adjacent three plotted points are within the concentration value of 0.3, it is calculated from the average value of the three concentration points. D _tm Represents a density that is visually transparent when it is above this density.
[0023]
Furthermore, y = D on the graph _tm The temperature at the intersection with the concentration temperature curve is obtained. Of these intersections, the lower temperature side is defined as the lower transparency limit temperature (T _tl ), The high temperature side is made transparent upper limit temperature (T _tu ). The clearing temperature range (ΔTw) is determined by Equation (II).
[0024]
[Expression 2]
ΔTw = T _tu -T _tl ... Formula (II)
Further, the white turbidity upper limit concentration (Ds) is calculated by Formula (III).
[0025]
[Equation 3]
Ds = D _min + 0.1 × (D _tav -D _min ) ・ ・ ・ ・ ・ Formula (III)
A line y = Ds is drawn on the graph, and the temperature at the intersection with the portion where the concentration-temperature curve changes from transparent to cloudy is expressed as the clouding lower limit temperature (T _sl ). Difference between upper limit of clarification and lower limit of turbidity (ΔT _ts ) Is calculated by the formula (IV).
[0026]
[Expression 4]
ΔT _ts = T _sl -T _tu ... Formula (IV)
Clearing start density (D _ta ) Is obtained by the following equation (V).
[0027]
[Equation 5]
D _ta = D _min + 0.25 × (D _tav -D _min ) ・ ・ ・ ・ ・ Formula (V)
Clearing start temperature (T _ta ) Is y = D as shown in FIG. _ts And the intersection of the graphs.
[0028]
Clarification upper limit temperature (T _tu ) Must be 125 ° C. or higher. T _tu When the temperature becomes high, the transparency temperature range can be expanded without deteriorating the image durability. Clarification upper limit temperature (T _tu ) Is preferably 130 ° C. or higher, more preferably 135 ° C. or higher, and particularly preferably 140 ° C. or higher. As this temperature increases, the print sensitivity improves. T _tu Is preferably 190 ° C. or lower, more preferably 180 ° C. or lower, and particularly preferably 170 ° C. or lower. The lower the temperature, the higher the printing sensitivity.
[0029]
Difference between upper limit of clarification and lower limit of turbidity (ΔT _ts ) Must be 20 ° C. or lower. ΔT _ts If this value is larger than this, the temperature at which the cloudiness becomes higher than necessary is required, so very high energy is required when forming a cloudy image. The white turbidity will decrease. ΔT _ts Is preferably 15 ° C. or lower, more preferably 10 ° C. or lower.
[0030]
Clearing start temperature (T _ta ) Is less than 95 ° C. 90 ° C. or lower is more preferable, 85 ° C. or lower is particularly preferable, 70 ° C. or higher is preferable, and 75 ° C. or higher is particularly preferable. When this temperature is low, the erasability is improved, and when it is high, the image heat resistance is improved.
[0031]
Clarification temperature range (ΔT _w ) Is preferably 30 ° C. or higher. ΔT _w If it becomes smaller than this, the erasability deteriorates. Clarification temperature range (ΔT _w ) Is more preferably 40 ° C. or higher, more preferably 45 ° C. or higher, and particularly preferably 50 ° C. or higher. A wider temperature range improves erasability. ΔT _w Is preferably 100 ° C. or lower, more preferably 90 ° C. or lower, and particularly preferably 80 ° C. or lower. In particular, the transparency temperature range (ΔT _w ) Becomes wider, there is an advantage that uniform erasing is possible even if the processing speed at the time of erasing is increased. ΔT in this case _w Is preferably 60 ° C. or higher, more preferably 70 ° C. or higher. In particular, the transparency temperature range (ΔT _w ) Becomes wider, there is an advantage that uniform erasing is possible even if the processing speed at the time of erasing is increased. ΔT in this case _w Is preferably 60 ° C. or higher, more preferably 70 ° C. or higher.
[0032]
In order to prepare such a thermoreversible recording medium, the low molecular substance to be used is a point. That is, a linear hydrocarbon-containing compound (A) having a melting point of 130 ° C. or higher and a linear hydrocarbon-containing compound (B) having a melting point 30 ° C. lower than the melting point of the linear hydrocarbon-containing compound (A) are mixed. This is achieved by using. The melting point of the linear hydrocarbon-containing compound (A) is 130 ° C or higher, 135 ° C or higher is preferable, 140 ° C or higher is more preferable, and 200 ° C or lower And 190 ° C. or lower is more preferable, and 170 ° C. or lower is particularly preferable. The lower limit of the difference in melting point between the linear hydrocarbon-containing compound (A) and the linear hydrocarbon-containing compound (B) is 30 ° C. or higher. And Further, 40 ° C. or higher is more preferable, 50 ° C. or higher is particularly preferable, and the erasability is improved when the melting point difference is larger. The upper limit of the melting point difference is preferably 100 ° C. or less, more preferably 90 ° C. or less, and particularly preferably 80 ° C. or less. The smaller the upper limit of the melting point difference, the better the printing sensitivity.
[0033]
The lower limit of the melting point of the linear hydrocarbon-containing compound (B) is 40 ° C or higher, It is preferably 50 ° C. or higher, more preferably 60 ° C. or higher, particularly preferably 70 ° C. or higher, and a higher melting point improves heat resistance. The upper limit of the melting point is Less than 130 ° C, The temperature is preferably less than 110 ° C, more preferably less than 100 ° C, and particularly preferably less than 90 ° C. The lower this temperature, the better the erasability. Further, a linear hydrocarbon-containing compound (C) having a melting point of 10 ° C. or more higher than the melting point of the linear hydrocarbon-containing compound (B) and lower than the melting point of the linear hydrocarbon-containing compound (A) by 10 ° C. or more. You may mix. The contrast can be improved by mixing the linear hydrocarbon-containing compound (C). The melting point of the linear hydrocarbon-containing compound (C) is preferably 80 ° C. or higher, more preferably 90 ° C. or higher, particularly preferably 100 ° C. or higher, preferably lower than 150 ° C., more preferably lower than 140 ° C., lower than 130 ° C. Is particularly preferred.
[0034]
These linear hydrocarbon-containing compounds (A), (B), and (C) may be used alone or in combination. These preferably have a long chain structure, and the long chain structure preferably has 4 or more carbon atoms, more preferably 6 or more, and particularly preferably 8 or more. When the number of carbon atoms is large, repeated durability is improved. This long chain structure may be one in one molecule, or two or more. Moreover, the carbon number of the long chain structure is shown as the total of the whole molecule. That is, a molecule having 2 long chain structures having 6 carbon atoms is defined as having a long chain structure having 12 carbon atoms.
[0035]
When the linear hydrocarbon-containing compound (A) and the linear hydrocarbon-containing compound (B) are mixed, the ratio of the linear hydrocarbon-containing compound (A) to the whole organic low molecular weight substance is 3% or more. Preferably, it is more preferably 5% or more, particularly preferably 10% or more, and the larger the ratio, the better the erasability. Further, it is preferably less than 50%, more preferably less than 40%, and particularly preferably less than 30%. The smaller this ratio, the better the transparency. The ratio of the linear hydrocarbon-containing compound (B) is preferably 30% or more, more preferably 50% or more, and particularly preferably 60% or more. The smaller the ratio, the better the erasability. Further, it is preferably less than 95%, more preferably less than 90%, and particularly preferably less than 85%. The larger this ratio, the better the transparency during erasure.
[0036]
When the linear hydrocarbon-containing compound (C) is further mixed with these, the ratio of the linear hydrocarbon-containing compound (C) to the whole organic low molecular weight material is preferably 3% or more, more preferably 5% or more. % Or more is particularly preferable, and the larger the ratio, the better the transparency. Further, it is preferably less than 50%, more preferably less than 40%, and particularly preferably less than 30%. The smaller this ratio, the better the erasability.
[0037]
An object of the present invention is to provide a linear hydrocarbon-containing compound (A) having a melting point of 130 ° C. or higher having at least one of an amide bond, a urea bond, and a sulfonyl bond and a carboxyl group as at least part of the organic low molecular weight substance in the heat-sensitive layer. And at least one linear hydrocarbon-containing compound (B) having a melting point 30 ° C. lower than the melting point of the linear hydrocarbon-containing compound (A). The amide bond, urea bond, and sulfonyl bond may be one or more of the same type, or may be one or more of the different types, and may be at the end or the center of the molecule. . In addition, the carboxyl group may be one or more, and may be located at the end of the molecule or in the side chain.
The linear hydrocarbon-containing compound (A) preferably has an amide bond and a carboxyl group. More preferably, at least one of the amide bond and the carboxyl group is plural, and it is particularly preferable that both the amide bond and the carboxyl group are plural. Although the example of the general formula of the linear hydrocarbon containing compound (A) which has an amide bond and a carboxyl group is given to the following, it is not limited to this.
[0038]
[Chemical formula 5]
HOOC- (CH ₂ ) n-X- (CH ₂ ) m-Y- (CH ₂ ) n-COOH General formula (1)
(Here, 26 ≧ n ≧ 1, 26 ≧ m ≧ 1, X and Y represent CONH or NHCO, provided that X and Y do not have the same structure at the same time.)
2n + m is preferably 6 or more, more preferably 8 or more, and particularly preferably 10 or more.
The linear hydrocarbon-containing compound (A) preferably has a urea bond and a carboxyl group. The straight chain hydrocarbon-containing compound (A) preferably has a sulfonyl bond and a carboxyl group. Examples of the general formula of the straight chain hydrocarbon-containing compound (A) having a urea bond and a carboxyl group and the general formula of the straight chain hydrocarbon-containing compound (A) having a sulfonyl bond and a carboxyl group are listed below, but are limited thereto. Is not to be done.
[0039]
[Chemical 6]
CH _Three − (CH ₂ ) n-Z- (CH ₂ ) m-COOH General formula (2)
(Where 25 ≧ n ≧ 0, 26 ≧ m ≧ 1, Z is NHCONH or SO ₂ Represents. )
n + m is preferably 6 or more, more preferably 8 or more, and particularly preferably 10 or more.
[0040]
Of the material of general formula (1) Of those used in the present invention Melting point is 130 ° C or higher And 135 ° C. or higher is more preferable, 140 ° C. or higher is particularly preferable, and the higher the melting point, the better the erasability. Moreover, 200 degrees C or less And 180 ° C. or lower is more preferable, 170 ° C. or lower is particularly preferable, and 160 ° C. or lower is most preferable. The lower the melting point, the better the thermal sensitivity. Further, the melting point of the material of the general formula (2) is preferably 135 ° C. or higher, more preferably 140 ° C. or higher. The higher the melting point, the better the erasability. Moreover, 190 degrees C or less is preferable, 170 degrees C or less is more preferable, 150 degrees C or less is especially preferable. The lower the melting point, the better the thermal sensitivity. Although the specific example of each material is shown below, it is not limited to these.
[0041]
[Table 1]

[0042]
[Table 2]

[0043]
Substance No. (15) above (HOOC ・ (CH ₂ ) _Five -NHCO (CH ₂ ) _Ten -CONH- (CH ₂ ) _Five A synthesis example of COOH) is shown below, but is not limited thereto.
Ethylaminocaproate-hydrochloride 81.6 g, viridine 33.0 g, dodecanedioic acid 32.0 g and 1-hydroxybenzotriazole 63.9 g were dissolved in tetrahydrofuran 500 ml, and then 52.5 g of diisopropylcarbodiimide was added dropwise at room temperature. After dropwise addition, the mixture was stirred under reflux for 3 hours, and then 800 ml of a 90% ethanol aqueous solution in which 170 g of sodium hydroxide was dissolved was added to the reaction solution, and stirred for 4 hours under reflux. The reaction solution was acidified with 4N hydrochloric acid, and the precipitated crystals were filtered off, washed with water, dried and recrystallized from dimethylformamide to obtain 29.7 g of the desired compound. The substances No. (1) to No. (14) and No. (16) to No. (22) can be synthesized by the same method by changing the raw materials used.
[0044]
Substance No. (24) above (HOOC- (CH ₂ ) _Four -CONH (CH ₂ ) _Ten -NHCO- (CH ₂ ) _Four A synthesis example of -COOH) is shown below, but is not limited thereto.
90% aqueous ethanol solution in which 10.0 g of adipic acid monoethyl ester, 48.8 g of 1,10-diaminodecane, and 35.8 g of 1-hydroxybenzotriazole were dissolved in 1200 ml of tetrahydrofuran and then 29.4 g of diisopropylcarbodiimide was dissolved at room temperature. 1500 ml was added and stirred under reflux for 4 hours. The reaction solution was acidified with 4N hydrochloric acid, and the precipitated crystals were filtered off, washed with water, dried and recrystallized from dimethylformamide to obtain 16.4 g of the desired compound.
Although the synthesis example of the said No. (30) substance and the No. (33) substance is shown below, it is not limited to these.
[0045]
Substance of No. (30) (CH _Three -(CH ₂ ) ₁₇ -NHCONH- (CH ₂ ) ₂ -COOH)
Beta-alanine sodium salt 23.9g, octadecyl isocyanate 35.5g, 2-butanone 900ml were prepared, and it stirred under recirculation | reflux for 6 hours. Next, the precipitated crystals were separated, washed with water, poured into an acetic acid aqueous solution and stirred for 3 hours, and then separated again. The obtained crystals were washed with water, dried and recrystallized from toluene to obtain 25.7 g of the desired compound.
[0046]
Substance No. (33) (CH _Three -(CH ₂ ) ₁₇ -SO ₂ -(CH ₂ ) ₂ -COOH)
75.6 g of 1-octadecene, 26.8 g of thiopropionic acid and 200 ml of 2-butanone were charged and stirred for 12 hours under reflux. Water was added to the reaction solution, and the precipitated crystals were separated, washed with water, and then poured into 500 ml of acetic acid. Next, 450 ml of 30% hydrogen peroxide was added dropwise at 80 to 90 ° C., and the mixture was stirred for 10 hours. Thereafter, the precipitated crystals were filtered off, washed with water, and recrystallized from isopropanol to obtain 32.7 g of the desired compound.
[0047]
The long-chain hydrocarbon-containing compound (B) may be anything as long as it is in the above melting point range and has a long-chain structure. The long chain structure preferably has 8 or more carbon atoms, more preferably 10 or more, and particularly preferably 12 or more. Moreover, 50 or less is preferable, 40 or less is more preferable, and 30 or less is especially preferable.
[0048]
The long-chain hydrocarbon-containing compound (B) includes alkanol; alkanediol; halogen alkanol or halogen alkanediol; alkylamine; alkane; alkene; alkyne; halogen alkane; halogen alkene; Alkynes; saturated or unsaturated mono- or dicarboxylic acids or their esters, amides or ammonium salts; saturated or unsaturated halogen fatty acids or their esters, amides or ammonium salts; allylcarboxylic acids or their esters, amides or ammonium salts; halogens Allyl carboxylic acids or their esters, amides or ammonium salts; thioalcohols; thiocarboxylic acids or their esters, amines or ammonium salts; Acid ester and the like. These may be used alone or in combination of two or more. These compounds have 10 to 60 carbon atoms, preferably 10 to 38 carbon atoms, and particularly preferably 10 to 30 carbon atoms. The alcohol group part in the ester may be saturated, may not be saturated, or may be halogen-substituted. In any case, the organic low molecular weight substance has at least one of oxygen, nitrogen, sulfur and halogen in the molecule, for example, —OH, —COOH, —CONH, —COOR, —NH, —NH. ₂ , —S—, —S—S—, —O—, halogen and the like are preferable.
[0049]
Specifically, aliphatic monocarboxylic acid, aliphatic dicarboxylic acid, fatty acid ester, ketone having a higher alkyl group, dibasic acid ester, polyhydric alcohol difatty acid ester, fatty acid monoamide, represented by the following general formula (3) The substance represented by the general formula (4) is not limited thereto.
[0050]
[Chemical 7]
CH _Three (CH ₂ ) n-X- (CH ₂ ) M-COOH General formula (3)
(Here, the melting point of the substance of the general formula (3) is less than 130 ° C., 26 ≧ n ≧ 0, 26 ≧ m ≧ 0, where n + m ≧ 10, and Z is NHCONH, SO ₂ , CONH or NHCO. )
[0051]
[Chemical 8]
HOOC− (CH ₂ ) n-NHCO- (CH ₂ ) m-COOH General formula (4)
(Here, the melting point of the substance of the general formula (4) is less than 130 ° C., and 26 ≧ n ≧ 0, 26 ≧ m ≧ 0, where n + m ≧ 10.)
[0052]
Specific examples will be given below, but the present invention is not limited to these.
That is, specific examples of the aliphatic monocarboxylic acid include, for example, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, margaric acid, stearic acid, nonadecylic acid, arachidic acid, behenic acid, lignoceric acid, and serotic acid. , Montanic acid, melicic acid and the like.
[0053]
Specific examples of the aliphatic dicarboxylic acid include, for example, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecane Examples include diacid, heptadecanedioic acid, octadecanedioic acid, nonadecanedioic acid, eicosane diacid, heneicosane diacid, docosane diacid and the like.
[0054]
Specific examples of fatty acid esters include, for example, octadecyl laurate, docosyl laurate, docosyl myristate, dodecyl palmitate, tetradecyl palmitate, pentadecyl palmitate, hexadecyl palmitate, octadecyl palmitate, triaconyl palmitate, octadecyl palmitate, Docosyl palmitate, vinyl stearate, propyl stearate, isopropyl stearate, butyl stearate, amyl stearate, heptyl stearate, octyl stearate, tetradecyl stearate, hexadecyl stearate, heptadecyl stearate, octadecyl stearate, stearic acid Docosyl, hexacosyl stearate, triacontyl stearate, dodecyl behenate, behenic acid Octadecyl, docosyl behenic acid, lignoceric acid Torakoshiru include melissic acid myricyl like.
[0055]
Specific examples of the ketone having a higher alkyl group include, for example, 8-pentadecanone, 9-heptadecanone, 10-nonadecanone, 11-heneicosanone, 12-tricosanone, 14-heptacosanone, 16-hentriacontanone, 18-pentatriacontana. Non-22-tritetracontanone, 2-pentadecanone, 2-hexadecanone, 2-heptadecanone, 2-octadecanone, 2-nonadecanone and the like.
[0056]
The dibasic acid ester may be a monoester or a diester, and is represented by the following general formula (5).
[0057]
[Chemical 9]
ROOC- (CH ₂ ) n-COOR '... General formula (5)
(In the formula, R and R ′ represent a hydrogen atom or an alkyl group having 1 to 30 carbon atoms, and R and R ′ may be the same or different. n represents an integer of 0 to 40)
In the dibasic acid ester represented by the general formula (5), the alkyl group of R and R ′ preferably has 1 to 22 carbon atoms, n is preferably 1 to 30, and more preferably 2 to 20. The melting point is preferably 40 ° C. or higher.
[0058]
In particular,
Succinic acid diester
Adipic acid diester
Sebacic acid diester
1- or 18-octadecamethylene dicarboxylic acid ester
Etc.
[0059]
Examples of the polyhydric alcohol difatty acid ester of an organic low molecular weight substance used in the present invention include those represented by the following general formula (6).
[0060]
[Chemical Formula 10]
CH _Three (CH ₂ ) m- ₂ COO (CH ₂ ) nOOC (CH ₂ ) m- ₂ CH _Three ... General formula (6)
(In the formula, n is an integer of 2 to 40, preferably 3 to 30, more preferably 4 to 22. m is an integer of 2 to 40, preferably 3 to 30, and more preferably 4 to 22. )
Specific examples include the following.
1,3-propanediol dialkanoic acid ester
1,6 hexanediol dialkanoic acid ester
1,10 decanediol dialkanoic acid ester
1,18 octadecanediol dialkanoic acid ester
[0061]
Specific examples of the fatty acid monoamide include those represented by the following general formula (7).
[0062]
Embedded image
R ¹ -CONH-R ² ..... General formula (7)
(Where R ¹ Is a linear hydrocarbon chain having 1 to 25 carbon atoms, R ² Is hydrogen, a linear hydrocarbon chain having 1 to 26 carbon atoms, or a methylol group, R ¹ , R ² At least one of these is a linear hydrocarbon chain having 10 or more carbon atoms. )
Examples of these include nonanamide, decanamide, undecanamide, dodecanamide, tridecanamide, tetradecanamide, hexadecanamide, octadecanamide, icosanamide, docosanamide, tricosanamide, hexacosanamide, octacosanamide, and the like. .
[0063]
Moreover, the following are mentioned as an example of the substance represented by the said General formula (3) and General formula (4).
[0064]
[Table 3]

[0065]
[Table 4]

[0066]
In addition to the linear hydrocarbon-containing compound (A) and the linear hydrocarbon-containing compound (B), the melting point is 10 ° C. higher than the melting point of the linear hydrocarbon-containing compound (B), and the linear hydrocarbon You may mix 1 type, or 2 or more types of organic low molecular weight substances with melting | fusing point 10 degreeC or more lower than a containing compound (A). These are appropriately selected from the examples of the linear hydrocarbon-containing compound (B) described above.
[0067]
The resin base material used for the heat-sensitive layer is a material that forms a layer in which an organic low molecular weight substance is uniformly dispersed and held, and affects the transparency at the time of maximum transparency. Therefore, the resin base material is preferably a resin having good transparency, mechanical stability, and good film forming properties. Such resins include polyvinyl chloride; vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-vinyl alcohol copolymer, vinyl chloride-vinyl acetate-maleic acid copolymer, vinyl chloride-acrylate copolymer. Vinyl chloride copolymers such as polyvinylidene chloride, vinylidene chloride-vinyl chloride copolymers, vinylidene chloride copolymers such as vinylidene chloride-acrylonitrile copolymers; polyesters; polyamides; polyacrylates or polymethacrylates or acrylates Methacrylate copolymer; silicone resin and the like. Of course, these resins may be used alone or in combination of two or more.
[0068]
It is preferable to crosslink these resins. The cross-linked medium is less likely to change the internal structure of the heat-sensitive layer even after repeated printing and erasing, and the repeated durability is improved, for example, there is no decrease in white turbidity and transparency. In the case of crosslinking, the resin preferably has a functional group such as a hydroxyl group, a carboxyl group, or an epoxy group. Examples of the crosslinking method include thermal crosslinking, UV and EB irradiation methods, and it is preferable to perform crosslinking by adding isocyanate or various acrylic crosslinking agents. The glass transition temperature of the resin matrix is preferably 60 ° C. or higher, more preferably 70 ° C. or higher, preferably lower than 100 ° C., more preferably lower than 90 ° C. When the glass transition temperature increases, the image heat resistance improves, and when the glass transition temperature decreases, the erasability improves.
[0069]
The thickness of the thermosensitive layer of the thermoreversible recording medium of the present invention is preferably 1 to 30 μm, more preferably 2 to 20 μm. 4-15 micrometers is especially preferable. If the recording layer is too thick, heat distribution occurs in the layer, and it becomes difficult to make it transparent uniformly. On the other hand, if the heat sensitive layer is too thin, the turbidity is lowered and the contrast is lowered. The white turbidity can be increased by increasing the amount of fatty acid in the recording layer and crosslinking the resin in the heat sensitive layer. The ratio of the organic low molecular weight substance and the resin (resin having a crosslinked structure) in the heat-sensitive layer is preferably about 2: 1 to 1:16, more preferably 1: 2 to 1: 8 in terms of weight ratio. : 2 to 1: 5 is particularly preferable, 1: 2 to 1: 4 is more preferable, and 1: 2.5 to 1: 4 is more preferable. If the ratio of the resin is less than this, it becomes difficult to form a film in which the organic low molecular weight substance is held in the resin, and if it is more than this, the amount of the low molecular weight organic substance is small, and it becomes difficult to make it opaque. .
[0070]
Further, a protective layer can be provided on the heat sensitive layer in order to protect the heat sensitive layer. Examples of the protective layer (thickness: 0.1 to 5 μm) material laminated on the heat sensitive layer include silicone rubber, silicone resin (described in JP-A-62-221087), and polysiloxane graft polymer (JP-A-63-1). No. 317385), an ultraviolet curable resin, an electron beam curable resin (described in JP-A No. 02-566), or the like. In these, an organic or inorganic filler can be contained.
[0071]
Furthermore, an intermediate layer can be provided between the protective layer and the heat-sensitive layer in order to protect the heat-sensitive layer from the solvent, monomer component, etc. of the protective layer forming liquid (described in JP-A No. 1-133781). As the material for the intermediate layer, the following thermosetting resins, thermoplastic resins, UV curable resins, and EB curable resins can be used in addition to those listed as the resin base material in the heat sensitive layer. That is, polyethylene, polypropylene, polystyrene, polyvinyl alcohol, polyvinyl butyral, polyurethane, saturated polyester, unsaturated polyester, epoxy resin, phenol resin, polycarbonate, polyamide and the like can be mentioned. The thickness of the intermediate layer is preferably about 0.1 to 2 μm. If it becomes less than this, a protective effect will fall, and if it becomes more than this, thermal sensitivity will fall.
[0072]
The above-described problem of the present invention is that a heat-sensitive layer whose main component is a resin matrix and an organic low-molecular substance dispersed in the resin matrix and whose transparency changes reversibly depending on temperature is provided on a support. In a method for producing a thermoreversible recording medium, a dispersion in which an organic low molecular weight substance having a melting point of 130 ° C. or higher is used as at least a part of the organic low molecular weight substance and one or more organic low molecular weight substances are dispersed in a resin solution in a solid state This is achieved by a method for producing a thermoreversible recording medium, characterized in that an organic low molecular weight substance dispersed during heating and drying is dissolved in a dispersion solvent to form a heat-sensitive layer.
[0073]
It is preferable to use a mixture of two or more organic low molecular weight substances having melting points different by 30 ° C. or more. As organic low molecular weight substances usually have a higher melting point, they become difficult to dissolve in ordinary solvents at room temperature. In particular, when the melting point is 130 ° C. or higher, the tendency becomes remarkable. Disperse organic low molecular weight substances that are difficult to dissolve in these solvents, and dissolve them at the time of heating and drying the coating film. Organic low molecular weight substances are dispersed in spherical fine particles), and when two or more kinds of organic low molecular weight substances are used as described above, the transparent temperature range is wide and transparent and opaque. It is possible to obtain a thermoreversible recording medium having a large contrast with the state and easy temperature control for repeatedly generating a transparent state and an opaque state.
[0074]
Two or more kinds of solvents may be mixed, and it is preferable to use a solvent having a high boiling point, particularly a solvent having a boiling point of 100 ° C. or more as at least one kind of solvent, whereby the contrast between the transparent state and the opaque state is used. However, a larger thermoreversible recording medium can be obtained.
[0075]
Further, the content of the solvent having a high boiling point in the mixed solution is particularly preferably 10% by weight or more of the total solvent in the mixed solution, whereby an organic low molecular substance in which a resin matrix shape or two or more kinds of organic low molecular substances coexist is present. The domain shape becomes a spherical shape, an elliptical shape, or a rounded shape, whereby a thermoreversible recording medium capable of repeatedly producing a transparent state and an opaque state with high contrast many times can be obtained.
[0076]
In a preferred case where the method for producing a thermoreversible recording medium as described above is applied, as a low molecular weight organic substance in the dispersion, the dispersion solvent is used at the drying temperature when the mixture is applied onto the support and dried. This is a case of using a low molecular weight organic substance that dissolves in the water. In particular, it is preferable to use an organic low molecular weight substance that dissolves 0.5% or more in the dispersion solvent. Moreover, it is preferable that the solubility of the organic low molecular weight substance dispersed in the dispersion liquid with respect to the dispersion solvent at room temperature is less than 0.5%. The average dispersed particle size of the organic low molecular weight material is preferably 20 μm or less, more preferably 10 μm or less, and particularly preferably 5 μm or less.
[0077]
By using such an organic low molecular weight substance, the organic low molecular weight substance is once dissolved in a solvent at the time of drying, and two or more kinds of organic low molecular weight substances in the dispersion coexist through a phase separation process. Is formed.
[0078]
The above-described problem of the present invention is that a heat-sensitive layer whose main component is a resin matrix and an organic low-molecular substance dispersed in the resin matrix and whose transparency changes reversibly depending on temperature is provided on a support. In a method for producing a thermoreversible recording medium, a dispersion liquid in which two or more organic low molecular substances are dispersed in a resin solution using an organic low molecular substance having a melting point of 130 ° C. or higher as at least a part of the organic low molecular substance Is coated on a support and dried by heating at a temperature lower than the melting point of the organic low molecular weight material having the highest melting point in the heat sensitive layer to form the heat sensitive layer, and then all the organic low molecular weight materials in the heat sensitive layer are formed. This is achieved by a method for producing a thermoreversible recording medium, wherein the thermosensitive layer is heated at a temperature equal to or higher than the melting point. It is preferable to use a mixture of two or more organic low molecular weight substances having melting points different by 30 ° C. or more.
[0079]
By applying this organic low molecular weight substance dispersion onto a support and drying it to form a reversible thermosensitive recording layer, and then subjecting the reversible thermosensitive recording layer to a heat treatment at a temperature above the melting point of the organic low molecular weight substance. Thus, a thermoreversible recording medium having a wide transparent temperature range, a large contrast between the transparent state and the opaque state, and easy temperature control for repeatedly generating the transparent state and the opaque state can be obtained.
This is because heat treatment is applied to the reversible thermosensitive recording layer, so that two or more kinds of organic low-molecular substances dispersed individually in the resin matrix in the reversible thermosensitive recording layer are melted and thermally expanded. This is due to the formation of an organic low-molecular substance domain in which two or more kinds of organic low-molecular substances coexist due to softening of the resin.
[0080]
In addition, by applying heat treatment to the reversible thermosensitive recording layer at a temperature equal to or higher than the melting point of the organic low-molecular substance, the resin matrix shape or the organic low-molecular substance domain shape in which two or more organic low-molecular substances coexist is spherical or elliptical. Thus, a reversible thermosensitive recording material can be obtained in which a transparent state and an opaque state having a large contrast can be repeatedly generated many times. The number of spherical, elliptical or round resin matrix shapes or organic low molecular substance domain shapes is particularly preferably 10% or more of the total resin matrix number or the total number of organic low molecular substance domains. In these production methods, when two or more kinds of organic low molecular weight substances are used, for example, one kind may be used in a dispersed state, and one kind may be used by being dissolved in a solvent at room temperature.
[0081]
In addition to the reversible thermosensitive layer, a colored layer provided thereon and a reversible thermosensitive layer thereon is preferable in order to make the reversible visible image easily visible. In this case, the colored layer can be composed of two or more sites having different reflectivities for visible light.
[0082]
By providing both a heat-sensitive layer capable of reversible display satisfying the above three conditions and an information storage unit on the same card, a part of the information stored in the information storage unit is displayed on the heat-sensitive layer, thereby possessing the card. Even if there is no special apparatus, a person etc. can confirm information only by seeing a card, and the convenience improves. The information storage unit may be anything that can store necessary information, but magnetic recording, IC, and optical memory are preferable. As the magnetic recording layer, commonly used iron oxide, barium ferrite, etc. and vinyl chloride-based, urethane-based or nylon-based resin, etc. are used, and the coating is formed on the support, or the resin is not used by a method such as vapor deposition or sputtering. It is formed. The magnetic recording portion may be provided on the opposite surface of the support to the heat-sensitive layer, or may be provided between the support and the heat-sensitive layer, on a part of the heat-sensitive layer. Further, a reversible thermosensitive material used for display may be used in the storage unit by a barcode, a two-dimensional code, or the like. Of these, magnetic recording and IC are more preferable.
[0083]
In the thermoreversible recording medium of the present invention, a thermoreversible recording label can be obtained by providing an adhesive layer or a pressure-sensitive adhesive layer on the opposite surface of the support to the thermosensitive layer forming surface. Commonly used materials can be used for the adhesive layer or the pressure-sensitive adhesive layer. Specific examples include 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, acrylate copolymer, methacrylate ester copolymer , Natural rubber, cyanoacrylate resin, silicon resin, and the like, but are not limited thereto. The material of the adhesive layer or the pressure-sensitive adhesive layer may be a hot melt type. Release paper may be used or non-release paper type may be used.
[0084]
By providing the adhesive layer or the pressure-sensitive adhesive layer in this manner, it can be applied to the whole surface or a part of a thick substrate such as a PVC card with a magnetic stripe, which is difficult to apply the heat-sensitive layer. This improves the convenience of the medium, such as displaying a part of the information stored in the magnetism. The thermoreversible recording label provided with such an adhesive layer or pressure-sensitive adhesive layer can be applied not only to the above-mentioned magnetic PVC card but also to a thick card such as an IC card or an optical card.
[0085]
These thermoreversible recording labels can be used in place of display labels on a disk cartridge containing a rewritable disk such as a floppy disk, MD, or DVD-RAM. FIG. 3 shows an example in which a thermoreversible recording label is pasted on an MD disk cartridge. Furthermore, in the case of a disc that does not use a disc cartridge such as a CD-RW, a thermoreversible recording label can be directly attached to the disc. It can be applied to uses such as automatically changing display contents in accordance with changes in the stored contents. FIG. 4 shows an example in which a thermoreversible recording label is pasted on a CD-RW. It is also possible to attach a thermoreversible recording label on a write-once disc such as a CD-R and rewrite and display part of the stored information added to the CD-R.
FIG. 5 shows an example of a configuration in which a thermoreversible recording label is formed on an optical information recording medium (CD-RW) using an AgInSbTe phase change type storage material. The basic configuration is that a first dielectric layer, an optical information storage layer, a second dielectric layer, a reflective heat dissipation layer, and an intermediate layer are provided on a substrate having guide grooves, and a hard coat layer is provided on the back surface of the substrate. Further, a thermoreversible recording label is stuck on the intermediate layer. The dielectric layer is not necessarily provided on both sides of the recording layer, but it is desirable to provide the first dielectric layer when the substrate is made of a material having low heat resistance such as polycarbonate resin.
[0086]
Furthermore, it may be used as a display label of a video tape cassette as shown in FIG.
As a method of providing a thermoreversible recording function on a thick card, a disc cartridge or a disc, in addition to the above-described method of applying a thermoreversible recording label, a method of directly applying a heat-sensitive layer on them or a heat-sensitive layer on another support beforehand. There is a method of forming a layer and transferring a heat sensitive layer onto a thick card, a disk cartridge or a disk. When transferring, an adhesive layer such as a hot melt type or an adhesive layer may be provided on the heat sensitive layer. When attaching a thermoreversible recording label on a rigid card, disk, disk cartridge, tape cassette, etc., or providing a heat-sensitive layer, the contact with the thermal head is improved to make the image uniform. It is preferable to provide a layer or sheet that is elastic and forms a cushion between the rigid substrate and the label or the heat-sensitive layer.
[0087]
In particular, when the reversible recording medium of the present invention is provided with a rewritable barcode, it is preferable that the reversible recording medium is composed of two or more parts having different reflectances. This is because when a human visually observes, for example, there is a color difference in addition to a light amount difference between a cloudy image portion and a colored non-image portion, and depending on the viewing angle, an excessive amount from the non-image portion is present. Since the glare caused by the reflected light is eliminated, it is easy to see a reversible visible image. On the other hand, when this is read by a device such as a reflection densitometer or bar code reader, the light is usually incident obliquely. The sensor is placed and read in a direction perpendicular to the surface. This is because it is only necessary to measure the result that the colored layer absorbs at least part of the visible light and lowers the contrast. Thus, the colored layer in the reversible thermosensitive recording medium of the present invention is composed of two or more sites having different reflectivities to visible light, and at least one of the sites absorbs visible light. When at least a part of the layer is made of a layer that reflects visible light, an image can be easily recognized visually, and high contrast can be obtained even by measurement using an apparatus.
[0088]
In order to obtain a high contrast necessary for reading a barcode in a reversible (reversible) thermosensitive layer, it is preferable that the average particle size of the organic low molecular weight material is in the range of 0.1 to 2.0 μm, and more appropriate It becomes a turbidity. And, the larger the average particle size of the dispersed organic low molecular weight material, the less it becomes a polycrystalline state, the less light scattering effect, the lower the white turbidity and the lower the contrast, The smaller the average particle size of the dispersed organic low molecular weight material, the more difficult it is to form a polycrystalline state in the dispersed matrix during crystal growth. In this case as well, the white turbidity is lowered and the contrast is lowered. Conceivable. Furthermore, when reading the barcode, if the average particle diameter of the organic low molecular weight particles is in the range of 1/8 to 2 times the wavelength of the light source when reading the barcode, the contrast when reading the barcode Is further improved. The reason why this phenomenon occurs has not been clarified yet, but it is presumed as follows. That is, it is considered that the white turbidity, that is, the light scattering degree, is determined by the size of the crystals in the organic low molecular weight material particles, and further, the size of the crystals is determined by the size of the organic low molecular weight material particles. This is because the area of the interface between the resin base material and the organic low molecular weight material dispersed in the resin base material is determined by the size of the low molecular weight material particles. It is speculated that the strength of the interaction with the molecular substance is determined and the strength of the interaction affects the size of the crystals in the particles. Further, there is a size of a crystal that is most likely to scatter light of a certain wavelength, and this differs depending on each material, but a crystal having a wavelength smaller than the wavelength of light tends to scatter light of that wavelength. That is, when the average particle size of the organic low molecular weight substance is in the range of 1/8 to 2 times the wavelength of the light for reading the barcode, the size of the individual crystals of the polycrystal in the organic low molecular weight substance particles in the cloudy state Is considered to be the size that most easily scatters light of that wavelength. When the average particle diameter is less than 1/8 of the wavelength of the reading light source, the scattering effect decreases, the turbidity decreases, the contrast decreases, and conversely, when it exceeds 2 times, the resin base material and the organic low molecular weight substance are reduced. It is thought that the interface between the resin matrix and the organic low molecular weight substance is reduced, and it becomes difficult to control the crystals in the organic low molecular weight substance particles. Decrease. As a method for controlling the particle size of the organic low molecular weight substance, mixing of a poor solvent, control of heating and drying during coating of the recording layer forming liquid, addition of a surfactant for controlling dispersibility, and the like can be considered. It is not limited to these.
[0089]
By the way, the wavelength of a light source for reading a conventional barcode is defined as 600 nm or more (JIS B9550), and a light source having a wavelength in the range of 600 nm to 1000 nm is usually used. Specifically, LEDs (having wavelengths of 660 nm and 940 nm are often used) and lasers (600 nm for He-Ne lasers, 680 nm, 780 nm, and 960 nm for semiconductor lasers are often used) can be mentioned.
[0090]
According to the bar code display in the reversible recording medium of the present invention, it is possible to read the bar code using the light source having a wavelength of 660 nm or more as described above, but it is also possible to use a light source having a shorter wavelength. In fact, higher contrast can be obtained by using a light source with a short wavelength. For example, when light of 400 to 600 nm is used, the contrast is nearly twice as large as that of light of 600 nm to 10,000 nm. This is considered to be because light having a shorter wavelength has a higher refractive index with respect to an organic low molecular weight substance, and light scattering increases, thereby improving white turbidity.
[0091]
The “barcode” used herein may be any information that can recognize optical changes such as the intensity of light and wavelength changes as information regardless of whether it is in the wavelength range of visible light. Other optical recognition pattern displays represented by two-dimensional barcode, OCR, and Carla code are also included.
[0092]
For example, as shown in FIG. 7a, the reversible thermosensitive recording medium of the present invention is a film in which a reversible thermosensitive recording layer (13) and a protective layer (14) are provided on a support (11), as shown in FIG. 7b. As shown in FIG. 7c, a film in which an aluminum reflective layer (12), a reversible thermosensitive recording layer (13) and a protective layer (14) are provided on a support (11). 11) A film in which an aluminum reflective layer (12), a reversible thermosensitive recording layer (13) and a protective layer (14) are provided on the support (11) and a magnetic recording layer (16) is provided on the back surface of the support (11). As shown in FIG. 8, it can be shaped into a card (21) having a print display section (23).
[0093]
Further, for example, as shown in FIG. 9a, a film in which an aluminum reflective layer (12), a reversible thermosensitive recording layer (13), and a protective layer (14) are provided on a support (11) is processed into a card shape. And it can be the form processed into the card shape while forming the hollow part (23) which accommodates an IC chip. In this example, the rewritable recording part (24) is labeled on a card-like reversible thermosensitive recording medium, and an IC chip embedding recess (23) is provided at a predetermined position on the back side of the reversible thermosensitive recording medium. In this recess (23), a wafer (231) as shown in FIG. 9b is incorporated and fixed. In the wafer (231), an integrated circuit (233) is provided on the wafer substrate (232), and a plurality of contact terminals (234) electrically connected to the integrated circuit (233) include a wafer substrate (232). Is provided. The contact terminal (234) is exposed on the back side of the wafer substrate (232), and a dedicated printer (reader / writer) electrically contacts the contact terminal (234) to read or rewrite predetermined information. It is configured to be able to. An example of the function of this reversible thermosensitive recording card will be described with reference to FIG.
[0094]
FIG. 10A is a schematic configuration block diagram showing the integrated circuit 233, and FIG. 10B is a configuration block diagram showing an example of data stored in the RAM. The integrated circuit (233) is composed of, for example, an LSI, and includes a CPU (235) capable of executing a control operation in a predetermined procedure, and a ROM (not shown) storing operation program data of the CPU (235). 236) and a RAM (237) capable of writing and reading necessary data. Further, the integrated circuit (233) receives an input signal, gives input data to the CPU (235), receives an output signal from the CPU (235), and outputs it to the outside, and an input / output interface (238) not shown. Includes a power-on reset circuit, a clock generation circuit, a pulse frequency division circuit (interrupt pulse generation circuit), and an address decoder circuit. The CPU (235) can execute the operation of the interrupt control routine according to the interrupt pulse periodically given from the pulse frequency dividing circuit. The address decoding circuit decodes address data from the CPU (235) and supplies signals to the ROM (236), RAM (237), and input / output interface (238). A plurality (eight in the figure) of contact terminals (234) are connected to the input / output interface (238), and predetermined data from the dedicated printer (reader / writer) is input from the contact terminals (234). The data is input to the CPU (235) via the output interface (238). The CPU (235) performs each operation in response to the input signal and according to the program data stored in the ROM (236), and sends predetermined data and signals to the card via the input / output interface (238). Output to the reader / writer.
[0095]
As shown in FIG. 10B, the RAM (237) includes a plurality of storage areas (239a) to (239g). For example, the card number is stored in the area (239a), ID data such as the cardholder's name, address, and telephone number is stored in (239b). The area (239c) can be used by the owner, for example. Information corresponding to the remaining valuable value or valuables is stored, and information corresponding to the used valuable value or valuables is stored in the areas (239d), (239e), (239f), and (239g).
[0096]
A method and apparatus for recording and erasing images on the thermoreversible recording medium will be described below. For image recording, an image recording means such as a thermal head or a laser that can partially heat the medium on the image is used. For image erasing, 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 110 ° C. or higher, more preferably 112 ° C. or higher, and particularly preferably 115 ° C. or higher.
[0097]
Further, by using the thermal head, it is possible to further reduce the size, reduce the power consumption, and a battery-driven handy type device is also possible. If one thermal head is used for both recording and erasing, the size can be further reduced. When recording and erasing with one thermal head, after erasing all previous images once, new images may be recorded again, or by changing energy for each image and erasing the previous image at once, new An overwrite method for recording images is also possible. With the overwrite method, the time required for recording and erasing is reduced, leading to faster recording.
In the case where a card having a heat sensitive layer and an information storage unit is used, the above-mentioned device includes means for reading and rewriting the information stored in the information storage unit.
[0098]
FIG. 11 shows a specific example of the thermoreversible recording apparatus of the present invention.
FIG. 11a shows a schematic example of an apparatus in the case of erasing an image with a ceramic heater and forming an image with a thermal head according to the present invention. In the thermoreversible recording apparatus of FIG. 11a, first, information stored in the magnetic recording layer of the recording medium is read with a magnetic head, and then the image recorded on the reversible thermosensitive layer is heated and erased with a ceramic heater. Based on the information read by the magnetic head, new processed information is recorded on the reverse heat-sensitive layer by the thermal head. Thereafter, the information on the magnetic recording layer is also rewritten with new information.
[0099]
That is, in the thermoreversible recording apparatus of FIG. 11a, the thermoreversible recording medium (1) provided with the magnetic recording layer on the opposite side of the thermosensitive layer is transported along a transport path illustrated by a reciprocating arrow, Or it is conveyed in the reverse direction in the apparatus along the conveyance path. The thermoreversible recording medium (1) is magnetically recorded or erased on the magnetic recording layer between the magnetic head (34) and the conveying roller (31), and the image is erased between the ceramic heater (38) and the conveying roller (40). Therefore, heat treatment is performed, and an image is formed between the thermal head (53) and the conveyance roller (47), and thereafter, it is carried out of the apparatus. As described above, the set temperature of the ceramic heater (38) is preferably 110 ° C. or higher, more preferably 112 ° C. or higher, and particularly preferably 115 ° C. or higher. However, the rewriting of the magnetic recording may be performed before or after the image is erased by the ceramic heater. If desired, after passing between the ceramic heater (38) and the transport roller (40), or after passing between the thermal head (53) and the transport roller (47), the transport path is transported in the opposite direction, and the ceramic heater ( 38) The second heat treatment and the second printing process by the thermal head (53) can be performed.
[0100]
In the thermoreversible recording apparatus of FIG. 11b, the thermoreversible recording medium (1) inserted from the entrance / exit (30) travels along the transport path (50) shown by the one-dot broken line, or the transport path ( 50) in the reverse direction in the apparatus. The thermoreversible recording medium (1) inserted from the entrance / exit (30) is transported in the recording apparatus by the transport roller (31) and the guide roller (32) and reaches a predetermined position in the transport path (50). 33) is recognized by the control means (34c) by the control means (34c), and magnetic recording or recording is erased on the magnetic recording layer between the magnetic head (34) and the platen roller (35), and the guide roller (36) and the transport roller ( 37), and passes between the guide roller (39) and the conveying roller (40), and the sensor (43) recognizes its presence via the ceramic heater control means (38c) and operates. 38) and the platen roller (44) are subjected to heat treatment for image erasing, and are transported in the transport path (50) by the transport rollers (45), (46) and (47), and are moved to a predetermined position. The sensor (51) forms an image between the thermal head (53) and the platen roller (52), which operates by recognizing its presence via the thermal head control means (53c). 59) and the guide roller (60) through the outlet (61) and carried out of the apparatus. Here, as described above, the set temperature of the ceramic heater (38) is preferably 110 ° C. or higher, more preferably 112 ° C. or higher, and particularly preferably 115 ° C. or higher.
[0101]
Further, if desired, the conveyance path switching means (55a) is switched to the conveyance path (56b), and the conveyance moves in the reverse direction from the operation of the limit switch (57a) input by pressing the thermoreversible recording medium (1). After the heat reversible recording medium (1) is again heat-treated between the thermal head (53) and the platen roller (52) by the belt (58), the conveyance path (49b) connected by switching the conveyance path switching means (55b). ), Transported in the forward direction via the limit switch (57b) and the transport belt (48), and transported out of the transport path (56a) through the transport roller (59) and the guide roller (60) through the outlet (61). can do. Further, such a branched conveyance path and conveyance switching means can be provided on both sides of the ceramic heater (38), in which case the sensor (43a) is disposed between the platen roller (44) and the conveyance roller (45). It is desirable to provide in.
[0102]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples. In the examples, “parts” represents parts by weight.
Example 1
On a transparent polyester film (Lumirror T-60, manufactured by Toray Industries Inc.) with a thickness of about 50 μm,

A solution comprising the above was applied and dried by heating to provide a heat-sensitive layer having a thickness of about 12 μm. in addition,
10 parts of urethane acrylate UV curable resin
75% butyl acetate solution
(Dainippon Ink & Chemicals, Unidic C7-157)
10 parts isopropyl alcohol
The resulting solution was applied with a wire bar, dried by heating, and then irradiated with an ultraviolet ray with an 80 w / cm high-pressure mercury lamp to be cured, and an overcoat layer having a thickness of about 3 μm was provided to produce a thermoreversible recording medium.
[0103]
Example 2
Approximately 400cm of Al is vacuumed on the PET film side of Dainippon Ink & Chemicals, Inc. magnetic memory (memory dick DS-1711-1040: coated with a magnetic recording layer and a self-cleaning layer on a transparent PET film with a thickness of 188μm). A light reflecting layer was provided by vapor deposition. in addition,
10 parts of vinyl chloride-vinyl acetate-phosphate ester copolymer
(Denka Vinyl # 1000P, manufactured by Denki Kagaku Kogyo Co., Ltd.)
45 parts of methyl ethyl ketone
45 parts of toluene
A solution comprising the above was applied and dried by heating to provide an adhesive layer having a thickness of about 0.5 μm. Further thereon, a thermosensitive layer and an overcoat layer were provided in the same manner as in Example 1 to produce a thermoreversible recording medium.
[0104]
Example 3
A thermoreversible recording medium was produced in the same manner as in Example 1 except that the coating solution for the heat sensitive layer was changed as follows.

[0105]
Example 4
A thermoreversible recording medium was produced in the same manner as in Example 1 except that the coating solution for the heat sensitive layer was changed as follows.

[0106]
Example 5
A thermoreversible recording medium was produced in the same manner as in Example 1 except that the coating solution for the heat sensitive layer was changed as follows.

[0107]
Example 6
In a glass bottle,
6 parts of vinyl chloride-vinyl acetate copolymer
(VYHH, manufactured by Union Carbide)
Tetrahydrofuran 33 parts
Ethyl cellosolve 8 parts
Put the solution that comes from,
CH _Three (CH ₂ ) ₁₇ NHCONH (CH ₂ ) ₂ COOH 3 parts
In addition, ceramic beads having a diameter of about 2 mm were placed in a glass bottle and dispersed for about 18 hours using a paint shaker (manufactured by Asada Tekko Co., Ltd.) to prepare a dispersion (A) having a particle size of about 10 μm.
next,
7 parts behenic acid (SIGMA reagent, purity 99%)
32 parts of vinyl chloride-vinyl acetate copolymer
(VYHH, manufactured by Union Carbide)
Tetrahydrofuran 120 parts
Ethyl cellosolve 32 parts
A solution consisting of the following was prepared, and the solution 191 was mixed at a ratio of the dispersion (A) 50 to prepare a coating solution for the thermosensitive layer.
A thermoreversible recording medium was produced in the same manner as in Example 1 except that the coating solution for the heat sensitive layer was used.
[0108]
Comparative Example 1
A thermoreversible recording medium was produced in the same manner as in Example 1 except that the coating solution for the heat sensitive layer was changed as follows.
Behenic acid (SIGMA reagent, purity 99%) 5 parts
Eicosanedioic acid (manufactured by Okamura Oil Co., Ltd., SL-20-90) 5 parts
38 parts of vinyl chloride-vinyl acetate copolymer
(VYHH, manufactured by Union Carbide)
Tetrahydrofuran 210 parts
20 parts of toluene
[0109]
Comparative Example 2
On a transparent polyester film (Lumirror T-60, manufactured by Toray Industries Inc.) with a thickness of about 50 μm,
Behenic acid (SIGMA reagent, purity 99%) 6 parts
Eicosanedioic acid (manufactured by Okamura Oil Co., SL-20-90) 1 part
0.7 parts of 1,4-ciscyclohexanedicarboxylic acid
(Reagent made by Tokyo Chemical Industry Co., Ltd.)
1,4-transcyclohexanedicarboxylic acid 0.7 parts
(Reagent made by Tokyo Chemical Industry Co., Ltd.)
24 parts of vinyl chloride-vinyl acetate-vinyl alcohol copolymer
(Sekisui Chemical Co., Ltd., S REC A)
2.4 parts of isocyanate
(Curing agent, Asahi Kasei Co., Duranate 24A-100)
Triethylenediamine (Tokyo Chemical Co., Ltd. reagent, curing accelerator) 0.24 parts
Tetrahydrofuran 136 parts
Toluene 14 parts
After coating the solution, it was heated at 130 ° C. for 3 minutes, dried and cured to provide a heat-sensitive layer having a thickness of about 12 μm. An overcoat layer was provided thereon in the same manner as in Example 1 to produce a thermoreversible recording medium.
[0110]
Comparative Example 3
A thermoreversible recording medium was produced in the same manner as in Comparative Example 2 except that the coating solution for the heat sensitive layer was changed as follows.
9 parts behenic acid (SIGMA reagent, purity 99%)
1,4-ciscyclohexanedicarboxylic acid 0.5 part
(Reagent made by Tokyo Chemical Industry Co., Ltd.)
1,4-transcyclohexanedicarboxylic acid 0.5 part
(Reagent made by Tokyo Chemical Industry Co., Ltd.)
30 parts of vinyl chloride-vinyl acetate-vinyl alcohol copolymer
(Sekisui Chemical Co., Ltd., S REC A)
Isocyanate 3 parts
(Curing agent, Asahi Kasei Co., Duranate 24A-100)
Triethylenediamine (Tokyo Chemical Co., Ltd. reagent, curing accelerator) 0.3 parts
170 parts of tetrahydrofuran
17 parts of toluene
[0111]
Comparative Example 4
A thermoreversible recording medium was produced in the same manner as in Example 1 except that the coating solution for the heat sensitive layer was changed as follows.
33 parts of 12-tricosanone (manufactured by Tokyo Chemical Industry Co., Ltd., reagent)
11 parts of 14-heptacosanone (manufactured by Tokyo Chemical Industry Co., Ltd., reagent)
4 parts deoxycholic acid (manufactured by Tokyo Chemical Industry Co., Ltd., reagent)
100 parts of vinyl chloride-vinyl acetate copolymer
(VYHH, manufactured by Union Carbide)
550 parts of tetrahydrofuran
Toluene 55 parts
[0112]
Comparative Example 5
A thermoreversible recording medium was produced in the same manner as in Example 1 except that the coating solution for the heat sensitive layer was changed as follows.
30 parts of lignoceric acid ethyl (manufactured by Tokyo Chemical Industry Co., Ltd., reagent)
10 parts deoxycholic acid (manufactured by Tokyo Chemical Industry Co., Ltd., reagent)
100 parts of vinyl chloride-vinyl acetate copolymer
(VYHH, manufactured by Union Carbide)
570 parts of tetrahydrofuran
Toluene 57 parts
[0113]
Example 7
In a glass bottle,
5 parts of vinyl chloride copolymer
(MR-110, manufactured by Nippon Zeon Co., Ltd.)
Tetrahydrofuran 42 parts
Put the solution that comes from,
HOOC (CH ₂ ) _Five NHCO (CH ₂ ) _Four CONH (CH ₂ ) _Five COOH 3 parts
Further, ceramic beads having a diameter of about 2 mm were placed in a glass bottle and dispersed for about 48 hours using a paint shaker (manufactured by Asada Tekko Co., Ltd.) to prepare a dispersion (B) having a particle size of about 2 μm.
next,
7 parts behenic acid (Miyoshi Oil & Fats, B-95)
Eicosanedioic acid (manufactured by Okamura Oil Co., SL-20-90) 1.5 parts
24 parts of vinyl chloride copolymer
(MR-110, manufactured by Nippon Zeon Co., Ltd.)
125 parts of tetrahydrofuran
Orthoxylene 27 parts
A solution consisting of 18 parts by weight of this solution was mixed with 25 parts of the dispersion (B), and 2.5 parts of an isocyanate compound (manufactured by Nippon Polyurethane Co., Ltd., Coronate HK) was further mixed. A coating solution for the heat sensitive layer was prepared.
The heat-sensitive layer coating solution was applied on the light reflecting layer and the magnetic original adhesive layer with the adhesive layer produced in the same manner as in Example 2, and heated and dried at about 130 ° C. for 3 minutes to give about A 10 μm heat-sensitive layer was provided, and further allowed to stand in an environment of about 60 ° C. for 24 hours to crosslink the isocyanate and vinyl chloride copolymer in the recording layer.
Next, after providing an overcoat layer on the heat-sensitive layer in the same manner as in Example 1, heating was performed at about 150 ° C. for 30 seconds to melt the organic low-molecular substances in the heat-sensitive layer to each other, and a thermoreversible recording medium Was made.
[0114]
Example 8
7 parts of behenic acid of Example 7
5.2 parts of 12-tricosanone (manufactured by Tokyo Chemical Industry Co., Ltd., reagent)
14-heptacosanone (manufactured by Tokyo Chemical Industry Co., Ltd., reagent) 1.8 parts
A thermoreversible recording medium was produced in the same manner as in Example 7 except that.
[0115]
Example 9
HOOC (CH of dispersion (B) ₂ ) _Five NHCO (CH ₂ ) _Four CONH (CH ₂ ) _Five COOH, HOOC (CH ₂ ) _Three NHCO (CH ₂ ) ₁₂ CONH (CH ₂ ) _Three A thermoreversible recording medium was produced in the same manner as in Example 7 except that COOH was used and the heating temperature after providing the overcoat layer was 160 ° C.
[0116]
Example 10
HOOC (CH of dispersion (B) ₂ ) _Five NHCO (CH ₂ ) _Four CONH (CH ₂ ) _Five COOH, HOOC (CH ₂ ) _Five NHCO (CH ₂ ) ₂ CONH (CH ₂ ) _Five A thermoreversible recording medium was produced in the same manner as in Example 7 except that COOH was used and the heating temperature after the overcoat layer was provided was 175 ° C.
[0117]
Example 11
A thermoreversible recording label was prepared by providing an acrylic pressure-sensitive adhesive layer having a thickness of about 5 μm on the back surface of the thermosensitive layer surface of the support of the thermoreversible recording medium produced in Example 1. This label was formed into a donut shape as shown in FIG. 4 and pasted onto a CD-RW as shown in FIG. 5 to produce an optical information recording medium with a reversible display function.
Using the optical information recording medium produced as described above, a part of the information (date, time, etc.) stored in the CD-RW drive (MP6200S manufactured by Ricoh Co., Ltd.) is erased from the recording means (thermal head). Using a recording apparatus having means (ceramic heater), the recording energy of the thermal head was adjusted in accordance with the change in the recording temperature of each medium, displayed and recorded on the heat sensitive layer, and visualized. In addition, using the drive, the information in the storage layer of the optical information recording medium is rewritten, the erasing means is used by the recording device, the previous recording is erased, and the rewritten information is newly rewritten to the heat sensitive layer by the thermal head. did. Further, this display record rewriting was repeated 100 times, but recording and erasing were possible.
[0118]
Example 12
The thermoreversible recording label of Example 11 was pasted on a mini disk (MD) disk cartridge as shown in FIG. Using a recording device having recording means (thermal head) and erasing means (ceramic heater), a part of the information stored in the MD (year, month, date, song name, etc.) is used to record the recording energy of the thermal head of each medium. It was adjusted according to the change in recording temperature, recorded on the heat sensitive layer, and visualized. Further, this display record rewriting was repeated 100 times, but recording and erasing were possible.
[0119]
Comparative Example 6
A thermoreversible recording medium was produced in the same manner as in Example 2 except that the coating solution for the heat sensitive layer was changed as follows. In the heat-sensitive layer formed here, white particles were conspicuous and the uniformity was poor.
9.5 parts of behenate behenate (manufactured by Sigma, reagent)
Ethylene bisbehenamide 0.5 parts
(Nippon Kasei Co., Ltd., SLIPAX B)
30 parts of vinyl chloride-vinyl acetate copolymer
(VYHH, manufactured by Union Carbide)
160 parts of tetrahydrofuran
[0120]
Next, the thermoreversible recording media according to Examples 1 to 10 and Comparative Examples 1 to 6 were heated using a thermal tilt tester (manufactured by Toyo Seiki, HG-100), with a heating time of 1 second and a pressure of about 2.5 kg / cm. ² The temperature was changed at intervals of 5 ° C. and heated, and then cooled to room temperature. In the case of Example 1, Examples 3 to 6, and Comparative Examples 1 to 5, about 400 mm on the transparent PET film on the back of the heated part. A thick film of Al deposited (Toyo Metallizing Co., Ltd. # 50 Metal Me) was placed with the deposition side facing up. The concentration value after heating to each temperature was measured. The results are shown in FIGS.
From this figure, the maximum density value (D _max ), Average transparent density (D _tav ), Lower limit of transparency (D _tm ), Cloudiness upper limit concentration (D _s ), Transparency start density (D _ta ), Clouding lower limit temperature (T _sl ), Transparency start temperature (T _ta ), Transparency lower limit temperature (T _tl ), Transparency upper limit temperature (T _tu ), The difference between the clearing upper limit temperature and the clouding lower limit temperature (ΔT _ts ), Clearing temperature range (ΔT _w ) Was read or calculated. The results are shown in Tables 5 and 7.
[0121]
Further, the following measurement was performed. The results are shown in Tables 6 and 8.
(1) Contrast = D _tav -D _min (Calculated from the values in Tables 5 and 7)
(2) Erasability
Optimizing near the center of the erasing temperature after making the medium transparent in advance and using a reader / writer (R-3000) made by Kyushu Matsushita Electric Appliance to make it partially cloudy with a thermal gradient tester in an environment of 0 ° C. 50 sheets were erased at the erasing temperature, and the erasing state of the image was judged visually.
Y: All can be deleted
○ to △: A small amount of unerased residue occurs
△: Obvious unerasure occurs occasionally
×: Unerased frequently
(3) Heat resistance
After making the medium transparent in advance, the medium that was sufficiently heated with a thermal gradient tester and partially whitened was left in a constant temperature bath set at 60 ° C., 65 ° C., and 70 ° C. for 24 hours, and then taken out. The density value of the cloudy part (cloudy image) was measured using a Macbeth RD914 reflection densitometer.
(4) Optimal printing energy
After making the medium transparent in advance, the printing energy was increased using Oki Electric Co., Ltd. (RC-30 / M20), and the energy at which it became possible to sufficiently become clouded was determined as the optimum printing energy.
(5) Repeat durability-1
On each medium, an OP varnish (New Daicure GPOP varnish, manufactured by Dainippon Ink Co., Ltd.) having a thickness of about 2 μm was formed using an RI tester, and then cured by irradiating with ultraviolet light with a high-pressure mercury lamp. Each medium was printed with an optimum energy using an Oki Electric reader / writer (RC-30 / M20) and erased at an optimum erasing temperature. After printing and erasing were repeated 50 times, the state of scratches on the surface OP varnish was visually determined.
Y: Almost no occurrence
Δ: Some occurrence
Δ to ×: Slightly bad
×: Bad
(6) Repeat durability-2
Similar to “(5) Repeatability-1” except that printing is performed with an energy 40% higher than the optimum print energy of each medium obtained in “(5) Repeatability-1”. Printing and erasing were repeated 50 times. Thus, by increasing the printing energy by 40%, the forced test is about 10 times the same as the case of repeating 500 times with the optimum printing energy. The density value of the 50th image density was measured using a Macbeth RD914 reflection densitometer.
Here, in the evaluation of (2) erasability, (4) optimum printing energy, (5) repeat durability-1 and (6) repeat durability-2, Example 1, Examples 3-6 and Comparative Examples 1 No. 5 was evaluated after a 125 μm PET film was bonded to the medium with a double-sided tape. Examples 2, 7 to 10 and proportionality 6 were evaluated as they were.
[0122]
[Table 5]

[0123]
[Table 6]

[0124]
[Table 7]

[0125]
[Table 8]

[0126]
【The invention's effect】
As described above, as is clear from the detailed and specific description, according to the present invention, the temperature range for transparency is widened while maintaining the image heat resistance, and sufficient image erasability is sufficient even if the environmental temperature changes. Provided are a thermoreversible recording medium and a card using the same capable of obtaining contrast and good durability, and a manufacturing method therefor, an image method suitable for using these thermoreversible recording media, and The extremely excellent effect that the apparatus is provided is exhibited.
[Brief description of the drawings]
FIG. 1 is a diagram showing a change in transparency by a thermoreversible recording medium according to the present invention.
FIG. 2 is a diagram for explaining a maximum transparency temperature, a minimum whitening temperature, a transparency start temperature, and a transparency temperature range of a thermoreversible recording medium according to the present invention.
FIG. 3 is a diagram showing an example in which a thermoreversible recording label is pasted on an MD disk cartridge.
FIG. 4 is a diagram showing an example in which a thermoreversible recording label is pasted on a CD-RW.
FIG. 5 is a diagram showing an example of a configuration in which a thermoreversible recording label is formed on an optical information recording medium (CD-RW) using an AgInSbTe phase change type storage material.
FIG. 6 is a diagram showing a display label of a video tape cassette.
FIG. 7 is a diagram showing a layer configuration example of a thermoreversible recording medium according to the present invention.
FIG. 8 is a diagram illustrating an example of a thermoreversible recording medium according to the present invention.
FIG. 9 is a diagram for explaining another example of a thermoreversible recording medium according to the present invention.
FIG. 10 is a diagram illustrating an example of use of a thermoreversible recording medium according to the present invention.
FIG. 11 is a diagram illustrating an example of a thermoreversible recording apparatus according to the present invention.
FIG. 12 is a diagram showing a temperature-reflection density relationship of an example of a thermoreversible recording medium according to the present invention.
FIG. 13 is a diagram showing a temperature-reflection density relationship of another example of a thermoreversible recording medium according to the present invention.
FIG. 14 is a diagram illustrating a relationship between temperature and reflection density of a thermoreversible recording medium example of a comparative example.
FIG. 15 is a diagram showing a temperature-reflection density relationship of another thermoreversible recording medium example of a comparative example.
FIG. 16 is a diagram showing a temperature-reflection density relationship of another thermoreversible recording medium example according to the present invention.
FIG. 17 is a diagram showing a temperature-reflection density relationship of another thermoreversible recording medium example of a comparative example.
[Explanation of symbols]
1 Thermoreversible recording medium
11 Support
12 Aluminum reflective layer
13 Reversible recording layer
14 Protective layer
15 Transparent PET film
16 Air layer
17 Adhesive layer
20 Magnetic coating layer
21 cards
22 Rewrite recording section
23 IC chip recess
24 Label processing of rewrite recording part
30 doorway
31 Transport roller
32 Guide roller
33 sensors
34 Magnetic head
34c Control means
35 Platen roller
36 Guide roller
37 Transport roller
38 Ceramic heater
38c control means
39 Guide roller
40 Conveying roller
43 sensors
44 Platen roller
45 Transport roller
46 Conveying roller
47 Conveyance roller
48 Conveyor belt
49a Transport path
49b Transport path
50 Conveyance path
51 sensors
52 Platen Roller
53 Thermal Head
53c Control means
54 Conveyance path
55a Transport path switching means
55b Transport path switching means
56a Transport path
56b Transport path
57a Limit switch
57b Limit switch
58 Conveyor belt
59 Conveyor roller
60 Guide roller
61 Exit
231 wafer
232 Wafer substrate
233 integrated circuit
234 Contact terminal
235 CPU
236 ROM
237 RAM
238 I / O interface
239 RAM storage area information

Claims (28)

In a thermoreversible recording medium comprising a resin matrix and a low molecular weight organic substance dispersed in the resin matrix as a main component and having a thermosensitive layer whose transparency reversibly changes depending on temperature, as the organic low molecular weight substance, At least one linear hydrocarbon-containing compound (A) having a melting point of 130 ° C. or higher and 200 ° C. or lower having at least one of an amide bond, a urea bond, and a sulfonyl bond and a carboxyl group, and the melting point of the linear hydrocarbon-containing compound (A) At least one kind of the linear hydrocarbon-containing compound (B) having a melting point lower by 30 ° C. or higher and a melting point of 40 ° C. or higher and lower than 130 ° C., the linear hydrocarbon-containing compound (B) and the linear hydrocarbon-containing compound A thermoreversible recording medium which is used by mixing at a mixing ratio of 98: 2 to 10:90 of (A) and satisfying the following three conditions.
(1) Clearance upper limit temperature is 125 ° C. or more (2) Temperature difference between transparency upper limit temperature and clouding lower limit temperature is 20 ° C. or less (3) Clearance start temperature is less than 95 ° C.   The thermoreversible recording medium according to claim 1, wherein the transparent temperature range is 30 ° C. or more.   The thermoreversible recording medium according to claim 1 or 2, wherein the transparent upper limit temperature is 130 ° C or higher.   The thermoreversible recording medium according to any one of claims 1, 2, and 3, wherein a temperature difference between the clearing upper limit temperature and the clouding lower limit temperature is 15 ° C or less.   The thermoreversible recording medium according to any one of claims 1 to 4, wherein a linear hydrocarbon-containing compound having an amide bond and a carboxyl group is used as the linear hydrocarbon-containing compound (A). 6. The thermoreversible recording medium according to claim 5, wherein a material having a structure represented by the following general formula (1) is used as the linear hydrocarbon-containing compound (A).
[Chemical 1]
_{HOOC- (CH 2) n-X-} (CH 2) m-Y- (CH 2) n-COOH ····· general formula (1)
(Here, 26 ≧ n ≧ 1, 26 ≧ m ≧ 1, X and Y represent CONH or NHCO, provided that X and Y do not have the same structure at the same time.)   The thermoreversible recording medium according to any one of claims 1 to 4, wherein a linear hydrocarbon-containing compound having a urea bond and a carboxyl group is used as the linear hydrocarbon-containing compound (A).   The thermoreversible recording medium according to any one of claims 1 to 4, wherein a linear hydrocarbon-containing compound having a sulfonyl bond and a carboxyl group is used as the linear hydrocarbon-containing compound (A). The thermoreversible recording medium according to claim 7 or 8, wherein a material having a structure of the following general formula (2) is used as the linear hydrocarbon-containing compound (A).
[Chemical formula 2]
_{CH 3 - (CH 2) n} -Z- (CH 2) m-COOH ····· general formula (2)
(Here, 25 ≧ n ≧ 0, 26 ≧ m ≧ 1, Z represents NHCONH or SO ₂ )   As the organic low molecular weight substance, containing a linear hydrocarbon having a melting point 10 ° C. higher than the melting point of the linear hydrocarbon-containing compound (B) and 10 ° C. lower than the melting point of the linear hydrocarbon-containing compound (A) The thermoreversible recording medium according to any one of claims 1 to 9, wherein the compound (C) is mixed and used.   11. A heat sensitive layer comprising, as a main component, a resin base material and a low molecular weight organic substance dispersed in the resin base material, wherein the transparency reversibly changes depending on the temperature. The method for producing a thermoreversible recording medium according to any one of the above, wherein the organic low-molecular substance is a linear hydrocarbon having a melting point of 130 ° C. or higher and 200 ° C. or lower having at least one of an amide bond, a urea bond, and a sulfonyl bond and a carboxyl group. Of the straight-chain hydrocarbon-containing compound (B) having a melting point 30 ° C. or more lower than the melting point of the straight-chain hydrocarbon-containing compound (A) and at least one kind of the containing compound (A) and having a melting point of 40 ° C. or more and less than 130 ° C. At least one kind is mixed and used at a mixing ratio of 98: 2 to 10:90 of the linear hydrocarbon-containing compound (B) and the linear hydrocarbon-containing compound (A), and one or more organic compounds are used in the resin solution. Low molecular weight A thermoreversible recording characterized in that a dispersion liquid dispersed in a body state is coated on a support, dried by heating, and the organic low molecular weight substance dispersed during the heating and drying is dissolved in a dispersion solvent to form a heat-sensitive layer. A method for manufacturing a medium.   The solubility of the organic low molecular weight substance dispersed in the dispersion liquid with respect to the dispersion liquid solvent at a drying temperature when the dispersion liquid is applied to the support and dried is 0.5% or more. A method for producing the thermoreversible recording medium as described.   12. The method for producing a thermoreversible recording medium according to claim 11, wherein the solubility of the organic low molecular weight substance dispersed in the dispersion liquid with respect to the dispersion solvent at room temperature is less than 0.5%.   11. A heat sensitive layer comprising, as a main component, a resin base material and a low molecular weight organic substance dispersed in the resin base material, wherein the transparency reversibly changes depending on the temperature. In the method for producing a thermoreversible recording medium according to any one of the above, a linear hydrocarbon having a melting point of 130 ° C. or more and 200 ° C. or less having at least one of an amide bond, a urea bond, and a sulfonyl bond and a carboxyl group as the organic low molecular weight substance. Of the straight-chain hydrocarbon-containing compound (B) having a melting point 30 ° C. or more lower than the melting point of the straight-chain hydrocarbon-containing compound (A) and at least one kind of the containing compound (A) and having a melting point of 40 ° C. or more and less than 130 ° C. At least one kind is used by mixing at a mixing ratio of 98: 2 to 10:90 of the linear hydrocarbon-containing compound (B) and the linear hydrocarbon-containing compound (A), and two or more organic compounds are used in the resin solution. Low molecular weight The dispersion liquid dispersed in the body state is applied onto the support, and the heat sensitive layer is formed by heating and drying at a temperature lower than the melting point of the organic low molecular weight substance having the highest melting point in the heat sensitive layer. A method for producing a thermoreversible recording medium, comprising heating the thermosensitive layer at a temperature equal to or higher than the melting point of all organic low molecular weight substances.   A card, comprising: a thermoreversible recording unit having a thermoreversible recording medium that satisfies the conditions according to any one of claims 1 to 10; and an information storage unit.   The card according to claim 15, wherein the information storage unit is at least one selected from a magnetic recording layer, an IC, and an optical memory.   The card according to claim 16, comprising at least a thermoreversible recording portion, a support, and a magnetic recording layer, which are laminated in this order.   A thermoreversible recording medium comprising at least a thermoreversible recording portion having the thermoreversible recording medium according to any one of claims 1 to 10, a support, and an adhesive layer or an adhesive layer, which are laminated in this order. Record label.   A thermoreversible recording unit having the thermoreversible recording medium according to any one of claims 1 to 10 is formed on a cartridge containing a rewritable disk of stored information, or the label according to claim 18 is attached. A disc cartridge with a reversible display.   A thermoreversible recording portion having the thermoreversible recording medium according to any one of claims 1 to 10 is formed on a disk on which stored information can be rewritten or additionally written, or the label according to claim 18 is attached. A disc with a reversible display.   A thermoreversible recording unit having the thermoreversible recording medium according to any one of claims 1 to 10 is formed on a tape cassette in which stored information can be rewritten, or the label according to claim 18 is attached. Characteristic tape cassette with reversible display.   The card, label, disk cartridge, disk, or tape cassette according to any one of claims 15 to 21, wherein an image is formed on at least one copy by printing.   An image is recorded by heating using the thermoreversible recording medium, card, label, disk cartridge with reversible display, disk with reversible display, and tape cassette with reversible display according to any one of claims 1 to 10 or 15 to 22. And an erasing process.   The image processing method according to claim 23, wherein an image is recorded by a thermal head.   25. The image processing method according to claim 23, wherein the image is erased by a ceramic heater.   The image processing method according to claim 25, wherein the set temperature of the ceramic heater is 110 ° C or higher.   The image processing method according to claim 23, wherein the image is erased by a thermal head. Using a thermal head, overwriting the image that has already been formed, the image processing how according to claim 27, characterized in that for recording and erasing the new image of the image.

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