JP3998767B2

JP3998767B2 - Thermal destruction transfer foil

Info

Publication number: JP3998767B2
Application number: JP25145997A
Authority: JP
Inventors: 明子千代田
Original assignee: Dai Nippon Printing Co Ltd
Current assignee: Dai Nippon Printing Co Ltd
Priority date: 1997-09-02
Filing date: 1997-09-02
Publication date: 2007-10-31
Anticipated expiration: 2017-09-02
Also published as: JPH1178266A

Description

【０００１】
【発明の属する技術分野】
本発明は、感熱破壊型の印字記録部の記録層として金属薄膜層からなる印字記録部を形成する為の感熱破壊転写箔に関する。特に、サーマルヘッドによる印字適性に優れた感熱記録媒体を与える感熱破壊転写箔に関する。
【０００２】
【従来の技術】
これまでに、感熱破壊型印字機能を有する感熱記録媒体が、各種の形態で提案されている。例えば、磁気記録層等の他の記録方式の記録層を既に有する磁気カード等の情報記録媒体に、更に感熱破壊型の記録層を記録する印字記録部として付与したカード等の形態である。感熱破壊型の記録層には金属薄膜層を用い、サーマルヘッドやレーザービーム等で部分的に加熱すると金属薄膜層が部分的に破壊されて文字等の目視可能なパターンを可視情報として記録できるものである。そして、通常、印字記録部は、記録された文字等をより見易くする為の着色層、金属薄膜層を擦り傷等から保護する保護層等も設けた構成とする。この様な感熱破壊型印字機能は、感熱記録層となる金属薄膜層は真空蒸着法等によって、また、着色層や保護層等はグラビアコーティング法等によって、感熱記録媒体の基材上に直接形成することもできるが、この場合、基材には真空蒸着等の金属薄膜層形成時にかかる熱に対する耐熱性が無い材料は使用できない。そこで、基材に耐熱性が無い場合は、金属薄膜層、着色層、保護層等を設けた転写箔又は貼合シートを用いて、基材に転写又は貼合で金属薄膜層等からなる印字記録部を形成すれば良い（特開平１−２１４４８８号公報、特開平２−１３９３号公報、特開平５−３０９９４８号公報等を参照）。また、カード等の形態でその一部に印字記録部を設ける場合にも、転写箔や貼合シートによる形成が適するが、貼合シートの場合は印字記録部が凸状になりその周囲に段差が出来る為に、サーマルヘッドで記録する場合や、リーダーライター等に通す場合の障害となるので、貼合シートが納まる凹部をザグリ加工等によって基材に設ける必要があった。これに対して、転写箔は表面の段差をほとんど生じることなく印字記録部を設けられる為に好ましい形成手段である。
【０００３】
【発明が解決しようとする課題】
しかしながら、印字記録部の表面が非常に平滑であると、サーマルヘッドによって印字記録する際は、ヘッド表面と密着してヘッド搬送性が得られず、（位置固定の）サーマルヘッドに対して感熱記録媒体を円滑に搬送できない。すると、良好な印字が出来なかったり、時には感熱記録媒体が全く搬送されずに印字不可能となる場合もあった。また搬送不良はサーマルヘッド自体の破損原因にもなり、ヘッドの本来の耐久寿命まで使用する為にも、ヘッドと媒体との十分なヘッド搬送性を実現して媒体側の十分な搬送性を確保する事が必要があった。
この様な問題に対し、金属薄膜層からなる印字記録部を貼合シートで形成する場合では、表面に適当なヘッド搬送性を付与する為に、金属薄膜層上に設ける保護層中にシリコーン等の滑剤を添加することで解決できた。しかし、転写箔の場合では、金属薄膜層を有する転写層から転写基体を剥離する時は、転写基体のみが安定的に転写層から剥がれる必要があり、転写層内の層間で剥離するようでは困る。ヘッド搬送性の問題を保護層への滑剤の添加のみで解決した場合には、保護層への滑剤の添加は、転写箔製造時に保護層の次に積層する層（例えば後述のアンカー層等）との接着不良を引き起こし、転写基体の剥離時に転写層内で剥がれる原因となる可能性があり、逆に、転写箔として必要な層間接着力を得る為には、滑剤の種類と添加量にかなりの制限を生じる為、満足すべきヘッド搬送性が得られなかった。
この為、転写層内での層間の接着力とヘッド搬送性を同時に安定的に確保するためには、滑剤の添加以外の方法で解決する手段が必要であった。
【０００４】
【課題を解決するための手段】
そこで、上記課題を解決すべく、本発明の感熱破壊転写箔では、転写基体上に転写層として少なくとも、転写基体に隣接する樹脂層、アンカー層、錫を真空蒸着してなる金属薄膜層、アンカー層、着色層、接着層をこの順に有する感熱破壊記録媒体を得るための転写箔において、転写基体の転写層側の面の中心線平均粗さＲａが０．１〜１．５μｍである構成とした。この結果、転写層内での層間の接着力とヘッド搬送性を同時に安定的に確保できる様になった。
【０００６】
【発明の実施の形態】
以下、本発明の感熱破壊転写箔及び感熱記録媒体の実施の形態を説明する。
【０００７】
先ず、図１は本発明の感熱破壊転写箔の一形態を示す断面図である。また、図２及び図３は本発明の感熱破壊転写箔の他の形態例を示す断面図である。また、図４は、これら感熱破壊転写箔等によって得られる感熱記録媒体の一形態を示す断面図である。また図５は、その用途としてカード等の一部に設けた印字記録部に氏名、会員番号が印字された感熱記録媒体の一例を示す平面図である。
【０００８】
図１は本発明の感熱破壊転写箔Ｓの一つの形態を示す断面図であるが、本発明の感熱破壊転写箔Ｓは、転写層側が特定の表面粗さの転写基体１と転写層２とからなり、転写層２として少なくとも、転写基体に隣接し転写後は表面層となる樹脂層３と感熱記録用の金属薄膜層４とを有する。特に本発明の感熱破壊転写箔Ｓでは、転写基体１の転写層側の面の表面粗さが中心線平均粗さＲａで０．１〜１．５μｍとなっている。そして、更に図１の形態の感熱破壊転写箔Ｓの場合は、転写層２の構成要素として、接着層５、アンカー層６ａ及び６ｂ、着色層７を有する。同図の形態では、感熱破壊転写箔Ｓは、転写基体１側から転写層２は、順に樹脂層３、アンカー層６ａ、金属薄膜層４、アンカー層６ｂ、着色層７、接着層５の構成である。
【０００９】
次に、図４は、上記の様な感熱破壊転写箔を用いて得られる感熱記録媒体Ｍの一形態を示す断面図である。感熱記録媒体は、印字記録部として少なくとも、基材上に感熱記録用の金属薄膜層、最表面層となる樹脂層をこの順に有し、且つ樹脂層の表面粗さが中心線平均粗さＲａで０．１〜１．５μｍとした記録媒体であるが、同図に例示する感熱記録媒体Ｍは、図１に示す形態の感熱破壊転写箔Ｓで形成した印字記録部１０が基材Ｂの表面上の一部分に備える例である。印字記録部１０は、図１の転写層２が転写された感熱記録層８から成り、同図の印字記録部１０部分の感熱記録媒体は、表面側から前記特定表面粗さの樹脂層３、アンカー層６ａ、金属薄膜層４、アンカー層６ｂ、着色層７、接着層５、基材Ｂの順に積層された構成である。
【００１０】
ところで、感熱記録媒体の印字記録部の表面を粗面とするには、該印字記録部を感熱破壊転写箔で転写成形する場合では、転写箔に於ける転写基体の転写層側面を粗面とすることで達成される。この際、転写基体の粗面の表面粗さは、印字記録部の粗面の表面粗さと同程度で良い。なぜならば、印字記録部の表面層となる樹脂層に、転写基体の表面形状の凹凸が反転して、多少の違いは有ったとしてもほぼ同一形状に複製されて転写されるからである。そこで、本発明では転写基体の表面粗さと、印字記録部に於ける表面粗さは同一である（なお、実際には表１に示す如く、印字記録部の表面粗さの方が若干小さめとなる傾向がある）。これら表面粗さは中心線平均粗さＲａで０．１〜１．５μｍの範囲とすると良く、より好ましくは０．２〜１．０μｍとすると良い。中心線平均粗さＲａが０．１μｍ未満では、表面が平滑すぎて十分なヘッド搬送性が得られない。また、中心線平均粗さＲａが１．５μｍを超えると、表面凹凸が大きくなり過ぎてヘッドタッチが悪くなるため、印字の際に良好な熱伝達が行えず、印字感度が低下し、鮮明な画像形成ができなくなるため好ましくない。以上の特定の表面粗さとすることで、サーマルヘッドによる記録にて、良好なヘッド搬送性を確保でき、感熱記録媒体の搬送不良や、この為に生ずる印字不良等の発生を防止できる。しかも、搬送不良によるサーマルヘッドの破損も生じず、ヘッドの本来の耐久寿命までサーマルヘッドを使用できる。しかも、ヘッド搬送性の確保をシリコーン等の滑剤の添加のみで解決していないので、転写層内での層間の接着力とヘッド搬送性を同時に安定的に確保できることになる。
【００１１】
以下、さらに本発明を詳述する。
【００１２】
＜転写基体＞
転写基体１としては、感熱破壊転写箔を製造する際の耐熱性（特に金属薄膜層形成時の耐熱性）、耐溶剤性等を有し、且つ転写時の耐熱性等も有しているものであれば特に制限はない。例えば、ポリエチレンテレフタレート等のポリエステル樹脂、セルロースジアセテート、セルローストリアセテート等のセルロース系樹脂、スチレン系樹脂、ポリカーボネート、ポリイミド等のプラスチック類、銅、アルミニウム等の金属類、紙、含浸紙等の紙類などを単独又は積層体で用いる。具体的には、厚み２５μｍのポリエチレンテレフタレートフィルム等である。転写基体の厚みは特に制限は無いが、ポリエチレンテレフタレートフィルムの場合、２５μｍは製造及び転写時の加工適性、転写時の熱伝導性等の点から好ましい厚さの一つである。厚みが薄すぎると皺等が発生しやすく加工適性が低下し、厚みが厚すぎると転写時の熱伝導性が低下し、またコスト高となる。
【００１３】
（粗面化）
転写基体の転写層側の面は、前記特定の表面粗さの凹凸を有したものとする。この様な表面粗さの凹凸表面は、上記に例示した各種材料からなるフィルムや積層物に対してサンドブラスト加工、ケミカルマット加工、或いは材料自体にフィラー練り込み等の公知のマット加工処理によって得ることができる。また、下記の離型性樹脂層付きの転写基体とする場合は、該離型性樹脂層中にフィラーを練り込むか、離型性樹脂層積層後の積層物に対して上記の様なマット処理加工を行う。
【００１４】
（離型性樹脂層）
前記した材料自体では転写基体の転写層側面の剥離性が不足する場合は、図３で例示した様に転写基体１を主基体１ａと離型性樹脂層１ｂから構成しても良い。この離型性樹脂層は、転写基体の一部であり転写時は主基体と一体となって転写層と離れる層である。
離型性樹脂層１ｂの樹脂としては、主基体と密着性が良く且つ転写層（の転写基体と隣接する樹脂層）とは容易に剥離できる適度な剥離性が有る樹脂であれば特に制限はない。例えばメラミン系樹脂等の各種熱硬化性樹脂は耐熱性も有り好適である。離型性樹脂層の厚みは１〜５μｍ程度である。離型性樹脂層はグラビアコート等の塗工法やグラビア印刷等の公知の塗工又は印刷法で形成すれば良い。
また、離型性樹脂層は転写基体の転写層側の面を構成する層であり、離型性樹脂層の転写層側の面は、前記特定の表面粗さの粗面を有する。
離型性樹脂層の粗面は、主基体上に離型性樹脂層を形成後に前記サンドブラスト加工等のマット処理で形成することもできるが、離型性樹脂層を形成する為の塗液やインク組成物中にフィラーを添加したものを用いることでも容易に形成できる。フィラーとしては例えば粒径１〜５μｍ程度のシリカ等が好適なものの一つである。その他、炭酸カルシウム、水酸化アルミニウム、水酸化マグネシウム、タルク等のフィラーでも良い。添加量は、例えば樹脂分全量に対して１〜３０重量％程度が好適である。粒径が小さ過ぎると十分な粗面が得られず、逆に粒径が大き過ぎると粗面が粗くなりすぎて、サーマルヘッドとの接触が悪くなる。また、添加量が少な過ぎると十分な粗面が得られず、逆に添加量が多過ぎると、粗面が粗くなり過ぎたり、剥離性が低下したり、或いは離型性樹脂層自体の皮膜強度が低下したりする。
【００１５】
＜樹脂層＞
樹脂層３は、転写基体に隣接し転写後は印字記録部の表面に望ましい表面粗さの面を与える層である。また、樹脂層３は粗面を提供する機能の他に、金属薄膜層の保護層の機能を有し、また適宜、転写基体との剥離性調整の為の剥離層等の機能を提供する層でもある。保護層の機能としては、転写後の耐擦傷性、耐久性、印字時の耐熱性の他に、転写時の耐熱性等もある。
ちなみに樹脂層３は、図１の形態では、転写基体１の剥離性がそれ自体で適度であれば、剥離性を主体的に付与する機能は持たず、専ら保護層を主目的とした層であり、また、転写基体１の剥離性がそれ自体で不足する場合であれば、剥離性を付与する剥離層且つ保護層の機能を担う剥離保護層となる層である。
また、図２に示す感熱破壊転写箔Ｓの形態は、図１の形態の樹脂層３を転写基体１側から剥離層３ａ、保護層３ｂと２層で構成して機能分担した構成である。その他の層構成は、図１と同じである。保護層３ｂは剥離層３ａのみでは保護機能が不足する場合に設けると良い。
また、図３に示す感熱破壊転写箔Ｓの形態は、転写基体１を主基体１ａと離型性樹脂層１ｂとの積層物とし、樹脂層は保護を主目的とする保護層３ｂとした構成である。その他の層構成は、図１と同じである。なお主基体１ａは単層構成に限定されない。図３は、転写基体１が主基体１ａと離型性樹脂層１ｂとからなる点に一つの特徴があり、転写基体に接する樹脂層は保護層３ｂ以外でも良い。例えば、図１で説明した剥離保護層でも良い。つまり、離型性樹脂層と剥離保護層との連係で適切な剥離性を付与する。また、図２で説明した剥離層３ａと保護層３ｂとの２層構成の樹脂層でも良い。
【００１６】
以上の様に、樹脂層は適宜、保護層、剥離層、剥離保護層等として設けるが、その樹脂材料としては層目的、用途に合わせて適宜なものを選択使用すれば良く、特に制限は無い。例えば、アクリル系樹脂等の各種熱可塑性樹脂、ウレタン系樹脂等の熱硬化性樹脂、或いはアクリレート系等の電離放射線硬化性樹脂等は好適な樹脂である。なかでも専ら剥離層として設ける場合、アクリル系樹脂とセルロース系樹脂との混合物等は好ましい樹脂の一つである。また、剥離層と保護層と２層構成の場合の保護層、或いは離型性樹脂層を有する転写基体で転写基体と転写層との剥離性を専ら転写基体側で付与できる場合の樹脂層（保護層）は、転写基体との剥離性は無くても良い。樹脂層を剥離層及び剥離保護層等として設ける場合は転写基体から容易に剥離可能な剥離性のある樹脂（例えばアクリル系樹脂等）を用いると良い。
なお、樹脂層はその粗面によってヘッド搬送性を確保するが、ワックス等の滑剤を転写箔としての性能に支障を来さない範囲で樹脂層中に添加することを併用しても良い。これら滑剤を添加したとしても従来よりも少量で済ませることが出来、転写箔の性能低下への影響は少なく出来るからである。
樹脂層はグラビアコート等の塗工法やグラビア印刷等の公知の塗工又は印刷法で形成すれば良い。樹脂層の厚みは、感熱記録時の熱伝導に影響して印字感度を低下させない程度の厚みとし、また保護層の機能を担う場合は保護機能を損なわない程度の厚み以上とすれば良い。樹脂層は例えば１〜１０μｍ程度である。専ら剥離層とする場合は薄くても良いが、保護層の機能で設ける場合は必要十分な厚さとする。なお、樹脂層は透明性を維持しながら任意の色に着色しても良い。金属薄膜層の見かけの色を着色できる。
【００１７】
＜金属薄膜層＞
金属薄膜層４は、サーマルヘッドで熱溶融が可能な比較的低融点の金属又は金属化合物の薄膜を、真空蒸着法、スパッタリング法、メッキ法等の公知の薄膜形成法で形成すればよい。金属又は金属化合物としては、テルル、錫、インジウム、ビスマス、鉛、亜鉛、アルミニウム等の金属あるいはこれらの合金もしくはテルル−カーバーイト等の上記金属の化合物が挙げられる。
金属薄膜層の膜厚は、感熱破壊型の記録層として熱により薄膜が破壊される程度の厚さとし、薄膜の材料にもよるが１００Å〜１μｍ、好ましくは５００〜１０００Å程度である。
【００１８】
＜接着層＞
感熱破壊転写箔における接着層５は、転写する相手の被転写体の材質や、転写方法に応じて、公知の感熱接着剤や感圧接着剤等から適宜選択した接着剤をグラビアコート等の塗工法又はグラビア印刷等の印刷法等の公知の形成法で形成すれば良い。接着層に感熱接着剤を用いた場合の転写方法は、公知のホットスタンプ、ヒートローラなどの手段により熱圧により転写を行う。この際の転写温度は、接着剤が軟化し接着力が発現する温度以上で、且つ金属薄膜層を形成する金属又は金属化合物の融点より低い温度で行う。この条件での転写ならば、転写温度が金属薄膜層材料の融点よりも低い温度で行われるため、転写時の熱で金属薄膜層が破壊される事は無い。一方、接着層に感圧接着剤を用いた場合の転写方法は、適当な圧力を加えて被転写体に転写箔を押し当てて転写すれば良く、加熱は省略することができる。
用いる接着剤は、例えば感熱接着剤では、塩化ビニル−酢酸ビニル共重合体、エチレン−酢酸ビニル共重合体、アクリル系樹脂、ゴム系樹脂、アイオノマー樹脂、ポリオレフィン系樹脂等の単体又はこれらの混合物からなるものが使用される。また、感圧接着剤としては、例えばアクリル系粘着剤、ゴム系粘着剤等からなる粘着剤が使用される。なお、感圧接着剤の場合は、転写使用時まで接着層面に公知の離型シートを積層して保護しておくと良い。接着層の厚さは通常１〜２０μｍ程度である。薄すぎると接着力が得られず、厚すぎても無意味である。
なお、転写箔の接着層は、接着層を被転写体側に設けておく場合等では省略することも出来（例えば感熱記録媒体の基材全面に印字記録部を形成する場合等）、転写箔としては必ずしも必須ではない。しかし、通常の場合、転写箔には接着層は設ける。
【００１９】
＜アンカー層＞
アンカー層６ａ、６ｂは、金属薄膜層と接する層との間に介在させ層間密着力の向上や、或いは金属薄膜層形成時の下地層して、いずれか片方又は両方を適宜設ける。つまり、樹脂層３と金属薄膜層４間のアンカー層６ａは、樹脂層と金属薄膜層との接着強度が不足する場合に必要に応じて設ける。また、このアンカー層６ａは、場合によっては、印字感度を向上させる効果も得られる。また、アンカー層６ａは、樹脂層同様に透明性を維持しながら任意の色に着色しても良い。アンカー層６ａには、例えば、ポリエステル系樹脂、塩化ビニル−酢酸ビニル共重合体、塩化ビニル系樹脂等の熱可塑性樹脂、ウレタン系樹脂等の硬化性樹脂の単体又は混合物が使用できる。
アンカー層６ｂは、通常はそれに隣接して設ける着色層と金属薄膜層との接着強度が不足する場合に必要に応じて設ける。アンカー層６ｂは、着色層が無く接着層と金属薄膜層とが隣接しこれら層間の接着力不足の場合に設けても良い。アンカー層６ｂは、金属薄膜層の溶融破壊を良好にし、印字感度を向上させる、つまり感度良く鮮明に印字できる効果も有する。アンカー層６ａには、例えば、ポリエステル系樹脂、塩化ビニル−酢酸ビニル共重合体、塩化ビニル系樹脂等の熱可塑性樹脂、ウレタン系樹脂等の硬化性樹脂の単体又は混合物が使用できる。
なお、アンカー層６ａ及び６ｂの形成は、グラビアコート等の塗工法又はグラビア印刷等の印刷法等の公知の形成法で形成すれば良い。アンカー層６ａ及び６ｂの厚さは例えば１μｍ程度である。
【００２０】
＜着色層＞
着色層７は、金属薄膜層が破壊された部分で下地色として見える印字色を与える層であり、金属薄膜層の破壊部と非破壊部とのコントラストを向上させ、目視認識や機械認識を行い易くする層である。したがって、印字記録部を設ける基材色をそのまま利用できる場合は、もちろん着色層は省略できる。着色層の色は、黒をはじめ用途に応じて任意の色で良い。着色層は樹脂層やアンカー層で列記した様な各種樹脂の単体又は混合物中に任意色調の公知の顔料又は染料の着色剤を含有させた着色樹脂で形成する。着色層の形成は、グラビアコート等の塗工法又はグラビア印刷等の印刷法等の公知の形成法で形成すれば良い。
【００２１】
＜感熱記録媒体＞感熱記録媒体は、その印字記録部を上記本発明の感熱破壊転写箔を用いて転写で形成したものとして得ることができる。しかし、感熱記録媒体はその印字記録部となる部分の表面が前記特定の表面粗さを備えていれば良く、印字記録部は転写で形成したものに限定されない。感熱記録媒体の基材にザグリ加工をして形成した凹部中に、転写箔ではなく貼合シートの形態で印字記録部を設けたものでも良い。或いは基材に直接金属薄膜層を設けた上に、特定の表面粗さを持つ樹脂層を形成したものでも良い。しかし、前述した本発明の感熱破壊転写箔によって印字記録部を形成すれば、ザクリ加工も不要で、基材に耐熱性の無いプラスチックも使用でき、しかも印字記録部も基材の一部分等と必要部分のみに設けるられる上、容易に印字記録部を形成して感熱記録媒体を得ることができる。
【００２２】
感熱記録媒体の基材Ｂとしては、記録媒体の基材として要求される強度、剛性などの物性を備えたものであれば特に制限はない。例えば、塩化ビニル樹脂、ポリエステル系樹脂、スチレン系樹脂、ポリカーボネート、アクリル系樹脂、セルロース系樹脂、ポリプロピレン等のオレフィン系樹脂などのプラスチック類、銅、アルミニウムなどの金属類、或いは紙、含浸紙などの紙類を単独又は積層体で使用する。厚みは用途により異なるが、０．００５〜５ｍｍ程度である。薄すぎれば強度、剛性が得られず、厚すぎても嵩高となる。例えばカードの材質的形態では具体的にはプラスチックカードや紙カードである。
【００２３】
図４で感熱記録媒体を例示したが、印字記録部１０として、基材Ｂ上に感熱記録用の金属薄膜層４と、最表面層となる樹脂層３とをこの順に最低限有しており、且つ樹脂層の表面粗さが中心線平均粗さＲａで０．１〜１．５μｍであれば良い。つまり感熱記録層８は最低限金属薄膜層４と樹脂層３とからなる。従って、図４にて接着層５、アンカー層６ａ及び６ｂ、着色層７は場合により適宜省略される。この点については感熱破壊転写箔等の説明で前述した事と同様である。但し、印字記録部１０を貼合シートで形成す場合は、樹脂層３は貼合シートのシート基材が担う。貼合シートは表側となる面が前記特定の表面粗さを持った透明なシート基材を用いる。シート基材は前述の転写基体で列記したものが使用できる。また、金属薄膜層を真空蒸着等で基材に直接形成する場合の樹脂層３は、塗工（前記離型性樹脂層同様に形成）、粗面を持った透明フィルム（貼合シート同様の材料）ラミネート等で形成できる。
【００２４】
＜感熱記録媒体の用途＞感熱記録媒体の用途は特に制限はないが、各種カード、タグ、ラベル等の形態で各種用途に用いられ得る。図５は、カード等の一部に設けた印字記録部１０に氏名及び会員番号を目視可能な可視情報として印字済みの感熱記録媒体Ｍの用途例を示したものだが、印字記録部にはこの様に文字、或いはＯＣＲ文字、バーコード、図形等を印字して利用できる。印字する情報の内容は、氏名、会員番号、有効期限、使用履歴、ポイント等と任意である。もちろん、印字記録部以外の情報記録部を備えていも良く、例えば磁気記録部を備えた磁気カード、ＣＰＵやＩＣメモリ等を備えたいわゆるＩＣカード等に印字記録部を付与した形態でも良い。磁気カードやＩＣカードは定期券、乗車券、診察券、回数券、会員証、プリペイドカード、ポイントカード等である。
【００２５】
【実施例】
次に実施例及び比較例により本発明を更に説明する。
【００２６】
＜実施例１＞
図１に示す層構成の本発明の感熱破壊転写箔を次の様にして作製した。転写基体１として、片面がマット加工処理された厚さ２５μｍの透明ポリエチレンテレフタレートフィルムのマット面（中心線平均粗さＲａが０．１８μｍ）に対して、樹脂層３となる厚さ２μｍの剥離保護層をアクリル系樹脂とセルロース系樹脂との混合物で形成し、この上に厚さ０．５μｍのアンカー層６ａを塩化ビニル−酢酸ビニル共重合体の樹脂で形成した。これらはグラビア塗工で形成した。次いで、アンカー層６ａ上に、厚さ８００Åの金属薄膜層４を錫を真空蒸着して形成した。次いで、金属薄膜層４上に、順次、アンカー層６ａと同一材料からなる厚さ１．０μｍのアンカー層６ｂ、着色剤としてカーボンブラックを含有させたポリエステル系樹脂からなる黒色インキによる厚さ２μｍの着色層７、アクリル系樹脂と塩化ビニル−酢酸ビニル共重合体との混合系樹脂からなる厚さ２μｍの接着層５を、それぞれグラビア塗工で形成して、感熱破壊転写箔とした。
【００２７】
上記感熱破壊転写箔を用いて、図４に示す層構成の感熱記録媒体を次の様にして作製した。基材Ｂとして塩化ビニル樹脂製のカード上の一部分に、上記感熱破壊転写箔をホットスタンプを用いて熱圧を加えた後、転写基体のみを剥離して印字記録部を形成し、感熱記録媒体とした。転写条件は１４０℃１秒であった。印字記録部の表面粗さは中心線平均粗さＲａが０．１３μｍであった。なお、転写後の剥離した転写基体の表面粗さは中心線平均粗さＲａが０．１２μｍであった。そして、得られた感熱記録媒体に対する印字適性を評価する印字試験として、サーマルヘッド（６ｄｏｔ／ｍｍ）を用いて１．２〔ｍＪ／ｄｏｔ〕のエネルギーで印字した。その結果、表１に示す如くヘッド搬送性及び印字状態は良好で、これらによる印字適性の総合評価も良好であった。
【００２８】
＜実施例２＞
実施例１と同様の層構成で、ポリエチレンテレフタレートフィルムからなる転写基体の表面粗さのみを中心線平均粗さＲａを０．３６μｍとした他は、実施例１と同様にして、本発明の感熱破壊転写箔及び感熱記録媒体を作製した。印字記録部は中心線平均粗さＲａが０．２４μｍとなった。なお、転写後の剥離した転写基体は中心線平均粗さＲａが０．２５μｍであった。そして、印字試験の結果、表１に示す如く、ヘッド搬送性及び印字状態とも良好で、総合評価も良好となった。
【００２９】
＜実施例３＞
図３の層構成の感熱破壊転写箔とすべく、厚さ２５μｍの透明ポリエチレンテレフタレートフィルムからなる主基体１ａの片面に、粒径２〜３μｍのシリカを樹脂全量に対して２０重量％含有させたメラミン系樹脂からなる離型性樹脂層１ｂをグラビア塗工で形成して転写基体１を用意した。離型性樹脂層の表面粗さは中心線平均粗さＲａで０．５６μｍであった。その他は実施例１と同様にして、本発明の感熱破壊転写箔及び感熱記録媒体を作製した。印字記録部の表面粗さは中心線平均粗さＲａが０．４２μｍであった。なお、転写後の剥離した転写基体の表面粗さは中心線平均粗さＲａが０．４０μｍであった。そして、印字試験の結果、表１に示す如く、ヘッド搬送性及び印字状態は良好で、総合評価は良好となった。
【００３０】
＜実施例４＞
実施例３と同様の層構成で、離型性樹脂層中に含有させるシリカを粒径は５〜６μｍとし含有量は１５重量％とした他は、実施例３と同様にして、本発明の感熱破壊転写箔及び感熱記録媒体を作製した。転写基体は中心線平均粗さＲａが０．９８μｍであり、印字記録部は中心線平均粗さＲａが０．８５μｍであった。なお、転写後の剥離した転写基体は中心線平均粗さＲａが０．８９μｍであった。そして、印字試験の結果、表１に示す如く、ヘッド搬送性及び印字状態は良好で、総合評価は良好となった。
【００３１】
＜実施例５＞
実施例３と同様の層構成で、離型性樹脂層中に含有させるシリカの粒径のみを５〜６μｍとした他は、実施例３と同様にして、本発明の感熱破壊転写箔及び感熱記録媒体を作製した。転写基体は中心線平均粗さＲａが１．４７μｍであり、印字記録部は中心線平均粗さＲａが１．３１μｍであった。なお、転写後の剥離した転写基体の表面粗さは中心線平均粗さＲａが１．２８μｍであった。そして、印字試験の結果、表１に示す如く、ヘッド搬送性は良好でまた印字状態は若干のカスレが認められたが許容範囲内でほぼ良好で、総合評価はほぼ良好となった。
【００３２】
＜比較例１＞
実施例１に類似の層構成で、転写基体のみマット加工品では無い透明ポリエチレンテレフタレートフィルムとした他は、実施例１と同様にして、感熱破壊転写箔を作製した。ちなみに、転写基体は中心線平均粗さＲａが０．０５μｍであった。そして、この転写箔で実施例１と同様にして感熱記録媒体を作製した。印字記録部は中心線平均粗さＲａが０．０５μｍとなった。なお、転写後の剥離した転写基体は中心線平均粗さＲａが０．０４μｍであった。そして、印字試験の結果、表１に示す如く、表面粗さが小さ過ぎる為にヘッドが密着して感熱記録媒体が搬送されずヘッド搬送性は不良で、印字は不可能となり、総合評価は不良となった。
【００３３】
＜比較例２＞
実施例３と同様の層構成で、転写基体の離型性樹脂層に含有させるシリカの粒径のみを６〜７μｍとした他は、実施例３と同様にして、感熱破壊転写箔及び感熱記録媒体を作製した。転写基体は中心線平均粗さＲａが１．８５μｍであり、印字記録部は中心線平均粗さＲａが１．７７μｍであった。なお、転写後の剥離した転写基体は中心線平均粗さＲａが１．７３μｍであった。そして、印字試験の結果、表１に示す如く、ヘッド搬送性は良好であったが、印字状態は、表面粗さが大き過ぎる為にヘッドタッチが悪化し十分に熱が伝達できず印字感度が低下した為に印字が不鮮明となり判読困難で印字不良となった。その結果、総合評価は不良となった。
【００３４】
【表１】

【００３５】
【発明の効果】
（１）本発明の感熱破壊転写箔によれば、印字記録部の表面を粗面化する事により、サーマルヘッドとの接触面積を減少させ摩擦係数を低下させられるので、印字感度は低下させずに良好なヘッド搬送性を確保でき、感熱記録媒体の搬送不良や、更にこの為に生ずる印字不良も起きない。また、搬送不良によるサーマルヘッドの破損も生じず、ヘッドの本来の耐久寿命までサーマルヘッドを使用できる。
また、印字記録部の表面が粗面となる事により、印字時にヘッドに付着するヘッドカス等を、印字記録部自体の表面凹凸で除去するセルフクリーニング効果も得られる。
また、印字記録部表面の粗面の凹凸は、入射光を散乱するため、金属薄膜層の光沢感（ギラツキ感）を抑え、マット感を付与できる。これにより印字の視認性がより優れたものとなる。また、バーコード等の光学的な読み取りにも対応し易くなる。
また、特に感熱破壊転写箔としては、印字記録部を転写により成形することができるので、感熱記録媒体の基材の材質（耐熱性等）や形状を選ばず、任意の位置に任意の形状で印字記録部を設けることができる。しかも、ヘッド搬送性の確保をシリコーン等の滑剤のみにより実現していないので、転写層となる感熱記録層内の良好な層間密着力を確保でき転写箔としての安定的な剥離性を維持しつつ、ヘッド搬送性を確保できる。
【図面の簡単な説明】
【図１】本発明の感熱破壊転写箔の一形態を示す断面図。
【図２】本発明の感熱破壊転写箔の他の形態を示す断面図。
【図３】本発明の感熱破壊転写箔の他の形態を示す断面図。
【図４】感熱記録媒体の一形態を示す断面図。
【図５】感熱記録媒体の印字例を示す平面図。
【符号の説明】
１転写基体
１ａ主基体
１ｂ離型性樹脂層
２転写層
３樹脂層
３ａ剥離層
３ｂ保護層
４金属薄膜層
５接着層
６ａアンカー層
６ｂアンカー層
７着色層
８感熱記録層
１０印字記録部
Ｂ基材
Ｓ感熱破壊転写箔
Ｍ感熱記録媒体[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a metal thin film layer as a recording layer of a thermal destruction type print recording part. Consist of The present invention relates to a thermal destructive transfer foil for forming a print recording portion. In particular, a thermal recording medium with excellent printability using a thermal head Give body It relates to heat-sensitive destruction transfer foil.
[0002]
[Prior art]
So far, thermal recording media having a thermal destructive printing function have been proposed in various forms. For example, it may be in the form of a card or the like provided as a print recording unit for recording a thermal destruction type recording layer on an information recording medium such as a magnetic card that already has a recording layer of another recording system such as a magnetic recording layer. A metal thin film layer is used for the heat-sensitive destructive recording layer, and when the metal thin film layer is partially heated with a thermal head or laser beam, the metal thin film layer is partially broken so that visible patterns such as letters can be recorded as visible information. It is. In general, the print recording unit is provided with a colored layer for making it easier to see recorded characters and the like, and a protective layer for protecting the metal thin film layer from scratches and the like. Such a thermal destructive printing function is directly formed on the base material of the thermal recording medium by a vacuum vapor deposition method or the like for a metal thin film layer as a thermal recording layer, and a gravure coating method or the like for a colored layer or a protective layer. In this case, however, a material having no heat resistance against heat applied during the formation of a metal thin film layer such as vacuum deposition cannot be used for the substrate. Therefore, when the substrate is not heat resistant, a transfer foil or a bonding sheet provided with a metal thin film layer, a colored layer, a protective layer, etc. The And a printing recording portion composed of a metal thin film layer or the like may be formed on the substrate by transfer or bonding (Japanese Patent Laid-Open Nos. 1-214488, 2-1393, and 5-309948). See). Also, when a print recording part is provided in a part of a card or the like, formation with a transfer foil or a bonding sheet is suitable, but in the case of a bonding sheet, the printing recording part is convex and has a step around it. Therefore, when recording with a thermal head or passing through a reader / writer or the like, it becomes necessary to provide a concave portion in which the bonding sheet is accommodated on the substrate by counterboring or the like. On the other hand, the transfer foil is a preferable forming means because the print recording portion can be provided with almost no surface step.
[0003]
[Problems to be solved by the invention]
However, if the surface of the print recording part is very smooth, when printing and recording with a thermal head, it is in close contact with the head surface and head transportability cannot be obtained, and thermal recording is performed with respect to the (position-fixed) thermal head. The media cannot be transported smoothly. As a result, good printing could not be performed, and sometimes the thermal recording medium could not be printed without being conveyed at all. In addition, poor transport can cause damage to the thermal head itself, and in order to use the head for its original endurance life, sufficient head transport between the head and the medium is achieved to ensure sufficient transport on the medium side. It was necessary to do.
For such a problem, in the case where the print recording portion composed of a metal thin film layer is formed with a laminated sheet, silicone or the like is provided in the protective layer provided on the metal thin film layer in order to give an appropriate head transportability to the surface. This problem could be solved by adding a lubricant. However, in the case of the transfer foil, when the transfer substrate is peeled from the transfer layer having the metal thin film layer, only the transfer substrate needs to be stably peeled from the transfer layer, and it is not necessary to peel between the layers in the transfer layer. . When the problem of head transportability is solved only by the addition of a lubricant to the protective layer, the addition of the lubricant to the protective layer is a layer that is laminated next to the protective layer when the transfer foil is manufactured (for example, an anchor layer described later). In order to obtain the necessary interlayer adhesion for the transfer foil, the type and amount of lubricant are considerably different. Therefore, satisfactory head transportability could not be obtained.
For this reason, in order to ensure stable adhesion between the layers in the transfer layer and head transportability at the same time, means for solving the problem by a method other than the addition of a lubricant is required.
[0004]
[Means for Solving the Problems]
Therefore, in order to solve the above-described problems, in the thermal destruction transfer foil of the present invention, at least a resin layer adjacent to the transfer substrate as a transfer layer on the transfer substrate. Gold made by vacuum deposition of anchor layer and tin Metal thin film layer , Anchor layer, colored layer, adhesive layer Thermal breakdown with in this order To obtain a recording medium In the transfer foil, the center line average roughness Ra of the surface on the transfer layer side of the transfer substrate was 0.1 to 1.5 μm. As a result, the adhesive force between the layers in the transfer layer and the head transportability can be secured stably at the same time.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the thermal destruction transfer foil and the thermal recording medium of the present invention will be described.
[0007]
First, FIG. 1 is a cross-sectional view showing one embodiment of the heat-sensitive fracture transfer foil of the present invention. 2 and 3 are sectional views showing other embodiments of the heat-sensitive fracture transfer foil of the present invention. Moreover, FIG. 4 is obtained by these heat-sensitive destruction transfer foils. Feeling It is sectional drawing which shows one form of a thermal recording medium. FIG. 5 is a plan view showing an example of a heat-sensitive recording medium in which a name and a membership number are printed on a print recording unit provided on a part of a card or the like as its application.
[0008]
FIG. 1 is a cross-sectional view showing one embodiment of the thermal breakdown transfer foil S of the present invention. The thermal breakdown transfer foil S of the present invention includes a transfer substrate 1 and a transfer layer 2 having a specific surface roughness on the transfer layer side. The transfer layer 2 has at least a resin layer 3 adjacent to the transfer substrate and serving as a surface layer after transfer, and a metal thin film layer 4 for thermal recording. In particular, in the heat-sensitive fracture transfer foil S of the present invention, the surface roughness of the surface of the transfer substrate 1 on the transfer layer side is 0.1 to 1.5 μm as the center line average roughness Ra. Further, in the case of the heat-sensitive breaking transfer foil S in the form of FIG. 1, the adhesive layer 5, anchor layers 6 a and 6 b, and the colored layer 7 are included as the constituent elements of the transfer layer 2. In the form of the figure, the thermal destruction transfer foil S is composed of a resin layer 3, an anchor layer 6a, a metal thin film layer 4, an anchor layer 6b, a colored layer 7 and an adhesive layer 5 in this order from the transfer substrate 1 side. It is.
[0009]
Next, FIG. 4 is obtained using the above-described thermal destruction transfer foil. Feeling 2 is a cross-sectional view showing an embodiment of a thermal recording medium M. . Feeling The thermal recording medium has at least a metal thin film layer for thermal recording on the substrate and a resin layer as the outermost layer in this order as a print recording portion, and the surface roughness of the resin layer is centerline average roughness Ra. The recording medium has a thickness of 0.1 to 1.5 μm. Feeling The thermal recording medium M is an example in which the print recording unit 10 formed of the thermal destructive transfer foil S having the form shown in FIG. The print recording unit 10 includes a heat-sensitive recording layer 8 to which the transfer layer 2 of FIG. 1 is transferred. The heat-sensitive recording medium of the print recording unit 10 part of FIG. 1 includes the resin layer 3 having the specific surface roughness from the surface side, The anchor layer 6a, the metal thin film layer 4, the anchor layer 6b, the colored layer 7, the adhesive layer 5, and the base material B are laminated in this order.
[0010]
By the way, in order to make the surface of the print recording portion of the heat-sensitive recording medium rough, when the print recording portion is transferred and molded with a heat-sensitive breaking transfer foil, the transfer layer side surface of the transfer substrate in the transfer foil is made rough. Is achieved. At this time, the surface roughness of the rough surface of the transfer substrate may be approximately the same as the surface roughness of the rough surface of the print recording unit. This is because the unevenness of the surface shape of the transfer substrate is inverted on the resin layer that is the surface layer of the print recording portion, and is copied and transferred in substantially the same shape even if there are some differences. Therefore, in the present invention, the surface roughness of the transfer substrate is the same as the surface roughness in the print recording portion (in fact, as shown in Table 1, the surface roughness of the print recording portion is slightly smaller. Tend to be). The surface roughness is in the range of 0.1 to 1.5 μm as the center line average roughness Ra. When More preferably, it is good to set it as 0.2-1.0 micrometer. When the center line average roughness Ra is less than 0.1 μm, the surface is too smooth and sufficient head transportability cannot be obtained. On the other hand, if the center line average roughness Ra exceeds 1.5 μm, the surface unevenness becomes too large and the head touch becomes poor, so that good heat transfer cannot be performed during printing, and the printing sensitivity is lowered and clear. Na This is not preferable because image formation cannot be performed. By setting the specific surface roughness as described above, good head transportability can be ensured by recording with a thermal head, and it is possible to prevent the occurrence of poor transport of the thermal recording medium and the printing failure caused thereby. Moreover, the thermal head is not damaged due to poor conveyance, and the thermal head can be used up to the original durable life of the head. In addition, since the securing of the head transportability is not solved only by the addition of a lubricant such as silicone, the interlayer adhesive force and the head transportability in the transfer layer can be secured stably at the same time.
[0011]
The present invention will be further described in detail below.
[0012]
<Transfer substrate>
The transfer substrate 1 has heat resistance (particularly heat resistance when forming a metal thin film layer), solvent resistance, etc. when manufacturing a heat-sensitive fracture transfer foil, and also has heat resistance during transfer, etc. If there is no restriction in particular. For example, polyester resins such as polyethylene terephthalate, cellulose resins such as cellulose diacetate and cellulose triacetate, styrene resins, plastics such as polycarbonate and polyimide, metals such as copper and aluminum, paper such as paper and impregnated paper, etc. Are used alone or in a laminate. Specifically, it is a polyethylene terephthalate film having a thickness of 25 μm. The thickness of the transfer substrate is not particularly limited, but in the case of a polyethylene terephthalate film, 25 μm is one of the preferred thicknesses from the viewpoints of manufacturing and processing suitability during transfer, thermal conductivity during transfer, and the like. If the thickness is too thin, wrinkles and the like are likely to occur, and the workability is lowered. If the thickness is too thick, the thermal conductivity at the time of transfer is lowered and the cost is increased.
[0013]
(Roughening)
The surface on the transfer layer side of the transfer substrate has irregularities with the specific surface roughness. The uneven surface having such a surface roughness is obtained by a known mat processing such as sandblasting, chemical mat processing, or kneading filler into the material itself for the film or laminate made of the various materials exemplified above. Can do. In addition, when the transfer substrate with the following release resin layer is used, the above-mentioned mat is used for the laminate after the release resin layer is laminated or the filler is kneaded into the release resin layer. Perform processing.
[0014]
(Releasable resin layer)
If the above-described material itself does not have sufficient peelability on the side of the transfer layer of the transfer substrate, the transfer substrate 1 may be composed of a main substrate 1a and a release resin layer 1b as illustrated in FIG. This releasable resin layer is a part of the transfer substrate, and is a layer that separates from the transfer layer together with the main substrate during transfer.
The resin of the releasable resin layer 1b is not particularly limited as long as it is a resin having good releasability that can be easily peeled off from the transfer layer (the resin layer adjacent to the transfer base) with good adhesion to the main base. Absent. For example, various thermosetting resins such as melamine resins are preferable because of their heat resistance. The thickness of the releasable resin layer is about 1 to 5 μm. The releasable resin layer may be formed by a known coating or printing method such as a coating method such as gravure coating or gravure printing.
The releasable resin layer is a layer constituting a surface on the transfer layer side of the transfer substrate, and the surface on the transfer layer side of the releasable resin layer has a rough surface having the specific surface roughness.
The rough surface of the releasable resin layer can be formed by mat processing such as sandblasting after forming the releasable resin layer on the main substrate. The ink composition can be easily formed by using a filler added with a filler. For example, silica having a particle diameter of about 1 to 5 μm is a suitable filler. In addition, fillers such as calcium carbonate, aluminum hydroxide, magnesium hydroxide, and talc may be used. For example, the addition amount is preferably about 1 to 30% by weight with respect to the total resin content. If the particle size is too small, a sufficient rough surface cannot be obtained. Conversely, if the particle size is too large, the rough surface becomes too rough and the contact with the thermal head becomes poor. Also, if the addition amount is too small, a sufficient rough surface cannot be obtained. Conversely, if the addition amount is too large, the rough surface becomes too rough, the peelability is lowered, or the release resin layer itself is a coating film. The strength decreases.
[0015]
<Resin layer>
The resin layer 3 is a layer which is adjacent to the transfer substrate and gives a surface having a desired surface roughness to the surface of the print recording portion after transfer. In addition to the function of providing a rough surface, the resin layer 3 has a function of a protective layer for the metal thin film layer, and a layer that appropriately provides a function such as a release layer for adjusting the peelability from the transfer substrate. But there is. The protective layer functions include scratch resistance after transfer, durability, heat resistance during printing, and heat resistance during transfer.
Incidentally, in the form of FIG. 1, the resin layer 3 is a layer mainly intended for the protective layer without having a function of mainly imparting the releasability if the releasability of the transfer substrate 1 is moderate by itself. In addition, if the peelability of the transfer substrate 1 is insufficient by itself, it is a layer that becomes a peelable layer that provides the peelability and a protective layer that functions as a protective layer.
The form of the heat-sensitive fracture transfer foil S shown in FIG. 2 is a structure in which the resin layer 3 in the form of FIG. 1 is composed of two layers, that is, a release layer 3a and a protective layer 3b from the transfer substrate 1 side. Other layer configurations are the same as those in FIG. The protective layer 3b is preferably provided when the protective function is insufficient with the release layer 3a alone.
Further, in the form of the thermal breakdown transfer foil S shown in FIG. 3, the transfer substrate 1 is a laminate of a main substrate 1a and a release resin layer 1b, and the resin layer is a protective layer 3b whose main purpose is protection. It is. Other layer configurations are the same as those in FIG. The main substrate 1a is not limited to a single layer configuration. FIG. 3 has one feature in that the transfer substrate 1 is composed of a main substrate 1a and a releasable resin layer 1b, and the resin layer in contact with the transfer substrate may be other than the protective layer 3b. For example, the peeling protective layer described in FIG. 1 may be used. That is, appropriate releasability is imparted by linking the releasable resin layer and the peel protection layer. Moreover, the resin layer of the 2 layer structure of the peeling layer 3a demonstrated in FIG. 2 and the protective layer 3b may be sufficient.
[0016]
As described above, the resin layer is appropriately provided as a protective layer, a release layer, a release protective layer, etc., and as the resin material, an appropriate one may be selected and used according to the layer purpose and application, and there is no particular limitation. . For example, various thermoplastic resins such as acrylic resins, thermosetting resins such as urethane resins, or ionizing radiation curable resins such as acrylate resins are suitable resins. In particular, when a release layer is provided exclusively, a mixture of an acrylic resin and a cellulose resin is one of preferable resins. In addition, a protective layer in the case of a two-layer structure comprising a release layer and a protective layer, or a resin layer in the case where a transfer substrate having a releasable resin layer can provide the transfer substrate to the transfer layer exclusively on the transfer substrate side ( The protective layer may not be peelable from the transfer substrate. When the resin layer is provided as a release layer, a release protective layer, or the like, it is preferable to use a releasable resin (for example, an acrylic resin) that can be easily peeled off from the transfer substrate.
Although the resin layer ensures the head transportability by its rough surface, it may be used in combination with the addition of a lubricant such as wax to the resin layer as long as it does not hinder the performance as a transfer foil. This is because even if these lubricants are added, the amount of the lubricant can be reduced as compared with the conventional case, and the influence on the performance deterioration of the transfer foil can be reduced.
The resin layer may be formed by a coating method such as gravure coating or a known coating method or printing method such as gravure printing. The thickness of the resin layer may be set to such a thickness that does not deteriorate the printing sensitivity due to the influence of heat conduction during thermal recording, and when the function of the protective layer is assumed, the thickness of the resin layer may be set to a thickness that does not impair the protective function. The resin layer is, for example, about 1 to 10 μm. When the release layer is exclusively used, it may be thin. However, when it is provided by the function of the protective layer, it is necessary and sufficient thickness. The resin layer may be colored in any color while maintaining transparency. The apparent color of the metal thin film layer can be colored.
[0017]
<Metal thin film layer>
The metal thin film layer 4 may be formed by a known thin film forming method such as a vacuum deposition method, a sputtering method, or a plating method, by using a metal or metal compound thin film having a relatively low melting point that can be thermally melted by a thermal head. Examples of the metal or metal compound include metals such as tellurium, tin, indium, bismuth, lead, zinc, and aluminum, and alloys of these metals or compounds of the above metals such as tellurium-carbite.
The film thickness of the metal thin film layer is such that the thin film is destroyed by heat as a heat-sensitive destructive recording layer, and depending on the material of the thin film, it is 100 to 1 μm, preferably about 500 to 1000 mm.
[0018]
<Adhesive layer>
The adhesive layer 5 in the heat-sensitive breaking transfer foil is formed by applying a suitable adhesive selected from known heat-sensitive adhesives, pressure-sensitive adhesives, and the like according to the material of the transfer target to be transferred and the transfer method, such as gravure coating. What is necessary is just to form by well-known formation methods, such as a construction method or printing methods, such as gravure printing. As a transfer method in the case where a heat-sensitive adhesive is used for the adhesive layer, transfer is performed by heat pressure by means such as a known hot stamp or heat roller. The transfer temperature at this time is not less than the temperature at which the adhesive softens and exhibits adhesive strength, and is lower than the melting point of the metal or metal compound forming the metal thin film layer. In the transfer under this condition, the transfer temperature is lower than the melting point of the metal thin film layer material, so that the metal thin film layer is not destroyed by the heat during transfer. On the other hand, a transfer method using a pressure-sensitive adhesive for the adhesive layer may be performed by applying an appropriate pressure and pressing the transfer foil against the transfer target, and heating can be omitted.
The adhesive used is, for example, a heat-sensitive adhesive, such as vinyl chloride-vinyl acetate copolymer, ethylene-vinyl acetate copolymer, acrylic resin, rubber resin, ionomer resin, polyolefin resin, or a mixture thereof. Will be used. Moreover, as a pressure sensitive adhesive, the adhesive which consists of an acrylic adhesive, a rubber adhesive, etc., for example is used. In the case of a pressure-sensitive adhesive, a known release sheet may be laminated on the adhesive layer surface for protection until transfer use. The thickness of the adhesive layer is usually about 1 to 20 μm. If it is too thin, adhesive strength cannot be obtained, and if it is too thick, it is meaningless.
In addition, the adhesive layer of the transfer foil can be omitted when the adhesive layer is provided on the transfer target side (for example, when a print recording portion is formed on the entire surface of the base material of the thermal recording medium). Is not necessarily required. However, an adhesive layer is usually provided on the transfer foil.
[0019]
<Anchor layer>
The anchor layers 6a and 6b are interposed between the layers in contact with the metal thin film layer to improve interlayer adhesion, or as a base layer for forming the metal thin film layer, either one or both are provided as appropriate. That is, the anchor layer 6a between the resin layer 3 and the metal thin film layer 4 is provided as necessary when the adhesive strength between the resin layer and the metal thin film layer is insufficient. In addition, the anchor layer 6a also has an effect of improving the printing sensitivity depending on the case. Further, the anchor layer 6a may be colored in an arbitrary color while maintaining transparency as in the case of the resin layer. For the anchor layer 6a, for example, a polyester resin, a vinyl chloride-vinyl acetate copolymer, a thermoplastic resin such as a vinyl chloride resin, or a curable resin such as a urethane resin or a mixture thereof can be used.
The anchor layer 6b is provided as necessary when the adhesive strength between the colored layer and the metal thin film layer that are usually provided adjacent thereto is insufficient. The anchor layer 6b may be provided when there is no colored layer and the adhesive layer and the metal thin film layer are adjacent to each other and the adhesive force between these layers is insufficient. The anchor layer 6b has the effect of improving the melt fracture of the metal thin film layer and improving the printing sensitivity, that is, printing with high sensitivity and clarity. For the anchor layer 6a, for example, a polyester resin, a vinyl chloride-vinyl acetate copolymer, a thermoplastic resin such as a vinyl chloride resin, or a curable resin such as a urethane resin or a mixture thereof can be used.
The anchor layers 6a and 6b may be formed by a known forming method such as a coating method such as gravure coating or a printing method such as gravure printing. The thickness of the anchor layers 6a and 6b is, for example, about 1 μm.
[0020]
<Colored layer>
The colored layer 7 is a layer that gives a print color that appears as a base color at a portion where the metal thin film layer is broken. The colored layer 7 improves the contrast between the broken portion and the non-destructed portion of the metal thin film layer, and performs visual recognition and machine recognition. It is a layer that facilitates. Therefore, if the base color provided with the print recording portion can be used as it is, the colored layer can be omitted. The color of the colored layer may be any color such as black depending on the application. The colored layer is formed of a colored resin in which a known pigment or dye colorant having an arbitrary color tone is contained in a single resin or a mixture of various resins as listed in the resin layer and the anchor layer. The colored layer may be formed by a known forming method such as a coating method such as gravure coating or a printing method such as gravure printing.
[0021]
<Thermal recording medium > Feeling The thermal recording medium can be obtained by forming the print recording portion by transfer using the heat-sensitive destruction transfer foil of the present invention. However , Feeling As long as the surface of the part which becomes a printing recording part of the thermal recording medium has the specific surface roughness, the printing recording part is not limited to one formed by transfer. A print recording portion may be provided in the form of a bonding sheet instead of a transfer foil in a recess formed by counterboring the base material of the thermal recording medium. Alternatively, a metal thin film layer may be directly provided on the substrate and a resin layer having a specific surface roughness may be formed. However, if the print recording part is formed by the above-described heat-sensitive fracture transfer foil of the present invention, no pricking process is required, and a plastic having no heat resistance can be used for the base material, and the print recording part is also required as a part of the base material. In addition to being provided only in the portion, a print recording portion can be easily formed to obtain a thermal recording medium.
[0022]
The substrate B of the heat-sensitive recording medium is not particularly limited as long as it has physical properties such as strength and rigidity required for the substrate of the recording medium. For example, vinyl chloride resin, polyester resin, styrene resin, polycarbonate, acrylic resin, cellulose resin, plastics such as olefin resin such as polypropylene, metals such as copper and aluminum, paper, impregnated paper, etc. Papers are used alone or in a laminate. Although the thickness varies depending on the application, it is about 0.005 to 5 mm. If it is too thin, strength and rigidity cannot be obtained, and if it is too thick, it becomes bulky. For example, the material form of the card is specifically a plastic card or a paper card.
[0023]
FIG. Feeling Although the thermal recording medium is exemplified, the print recording unit 10 has at least the metal thin film layer 4 for thermal recording on the base material B and the resin layer 3 to be the outermost surface layer in this order, and the resin. The surface roughness of the layer may be 0.1 to 1.5 μm as the center line average roughness Ra. That is, the thermosensitive recording layer 8 comprises at least the metal thin film layer 4 and the resin layer 3. Therefore, in FIG. 4, the adhesive layer 5, the anchor layers 6a and 6b, and the colored layer 7 are omitted as appropriate. This is the same as described above in the description of the heat-sensitive fracture transfer foil and the like. However, when forming the printing recording part 10 with a bonding sheet, the resin layer 3 bears the sheet base material of the bonding sheet. The bonding sheet uses a transparent sheet base material whose front side has the specific surface roughness. As the sheet base material, those listed in the above-mentioned transfer substrate can be used. Moreover, the resin layer 3 in the case where the metal thin film layer is directly formed on the base material by vacuum deposition or the like is coated (formed in the same manner as the release resin layer), a transparent film having a rough surface (similar to the bonding sheet) Material) Can be formed by lamination or the like.
[0024]
<Applications of thermal recording media > Feeling The use of the thermal recording medium is not particularly limited, but can be used for various uses in the form of various cards, tags, labels, and the like. FIG. 5 shows an example of the use of the thermal recording medium M on which a name and a membership number are printed as visible information on a print recording unit 10 provided in a part of a card or the like. In this way, characters, OCR characters, barcodes, graphics, etc. can be printed and used. The contents of the information to be printed are arbitrary such as name, membership number, expiration date, usage history, points, and the like. Of course, an information recording unit other than the print recording unit may be provided. For example, a form in which the print recording unit is added to a magnetic card including a magnetic recording unit, a so-called IC card including a CPU, an IC memory, or the like may be used. Magnetic cards and IC cards are commuter tickets, boarding tickets, examination tickets, coupon tickets, membership cards, prepaid cards, point cards, and the like.
[0025]
【Example】
Next, the present invention will be further described with reference to examples and comparative examples.
[0026]
<Example 1>
The heat-sensitive fracture transfer foil of the present invention having the layer structure shown in FIG. 1 was produced as follows. As a transfer substrate 1, a 2 μm-thick peeling protection layer that forms a resin layer 3 on a matte surface (centerline average roughness Ra is 0.18 μm) of a 25 μm-thick transparent polyethylene terephthalate film that has been matted on one side The layer was formed of a mixture of an acrylic resin and a cellulose resin, and an anchor layer 6a having a thickness of 0.5 μm was formed thereon with a vinyl chloride-vinyl acetate copolymer resin. These were formed by gravure coating. Next, a metal thin film layer 4 having a thickness of 800 mm was formed on the anchor layer 6a by vacuum deposition of tin. Next, on the metal thin film layer 4, an anchor layer 6 b made of the same material as the anchor layer 6 a and having a thickness of 1.0 μm, and a black ink made of a polyester resin containing carbon black as a colorant are formed. The adhesive layer 5 having a thickness of 2 μm made of a colored resin 7 and a mixed resin of an acrylic resin and a vinyl chloride-vinyl acetate copolymer was formed by gravure coating to obtain a heat-sensitive fracture transfer foil.
[0027]
Using the heat-sensitive fracture transfer foil, the layer structure shown in FIG. Feeling of A thermal recording medium was produced as follows. A thermal recording medium is formed by applying heat pressure to the part made on the card made of vinyl chloride resin as a base material B using a hot stamp, and then peeling only the transfer base to form a print recording part. It was. The transfer condition was 140 ° C. for 1 second. As for the surface roughness of the print recording portion, the center line average roughness Ra was 0.13 μm. The surface roughness of the peeled transfer substrate after transfer had a center line average roughness Ra of 0.12 μm. Then, as a printing test for evaluating printing suitability for the obtained thermal recording medium, printing was performed with an energy of 1.2 [mJ / dot] using a thermal head (6 dots / mm). As a result, as shown in Table 1, the head transportability and the printing state were good, and the overall evaluation of printability by these was also good.
[0028]
<Example 2>
The thermosensitive material of the present invention was the same as in Example 1 except that the transfer layer made of polyethylene terephthalate film had the same layer structure as Example 1 and the center line average roughness Ra was 0.36 μm. A destructive transfer foil and a thermal recording medium were prepared. The print recording portion had a center line average roughness Ra of 0.24 μm. The transfer substrate peeled off after transfer had a center line average roughness Ra of 0.25 μm. As a result of the printing test, as shown in Table 1, both the head transportability and the printing state were good, and the overall evaluation was also good.
[0029]
<Example 3>
In order to obtain the heat-sensitive fracture transfer foil having the layer structure of FIG. 3, 20% by weight of silica having a particle diameter of 2 to 3 μm was contained on one side of the main substrate 1a made of a transparent polyethylene terephthalate film having a thickness of 25 μm based on the total amount of the resin. A releasable resin layer 1b made of a melamine resin was formed by gravure coating to prepare a transfer substrate 1. The surface roughness of the releasable resin layer was 0.56 μm as the center line average roughness Ra. Others were the same as in Example 1, and a heat-sensitive fracture transfer foil and a heat-sensitive recording medium of the present invention were produced. As for the surface roughness of the print recording portion, the center line average roughness Ra was 0.42 μm. The surface roughness of the peeled transfer substrate after transfer had a center line average roughness Ra of 0.40 μm. As a result of the printing test, as shown in Table 1, the head transportability and the printing state were good, and the overall evaluation was good.
[0030]
<Example 4>
In the same manner as in Example 3, except that the silica contained in the releasable resin layer has a particle size of 5 to 6 μm and a content of 15% by weight, the layer structure is the same as in Example 3. A heat-sensitive breaking transfer foil and a heat-sensitive recording medium were prepared. The transfer substrate had a center line average roughness Ra of 0.98 μm, and the print recording portion had a center line average roughness Ra of 0.85 μm. The transfer substrate peeled off after transfer had a center line average roughness Ra of 0.89 μm. As a result of the printing test, as shown in Table 1, the head transportability and the printing state were good, and the overall evaluation was good.
[0031]
<Example 5>
The heat-sensitive fracture transfer foil and the heat-sensitive foil of the present invention were the same as in Example 3, except that the particle size of the silica contained in the releasable resin layer was changed to 5 to 6 μm in the same layer configuration as in Example 3. A recording medium was produced. The transfer substrate had a center line average roughness Ra of 1.47 μm, and the print recording portion had a center line average roughness Ra of 1.31 μm. The surface roughness of the peeled transfer substrate after transfer had a center line average roughness Ra of 1.28 μm. As a result of the printing test, as shown in Table 1, the head transportability was good and the printing state was slightly blurred but was almost good within the allowable range, and the overall evaluation was almost good.
[0032]
<Comparative Example 1>
A heat-sensitive fracture transfer foil was prepared in the same manner as in Example 1 except that the layer structure was similar to that of Example 1 and the transfer substrate alone was a transparent polyethylene terephthalate film that was not a mat processed product. Incidentally, the transfer substrate had a center line average roughness Ra of 0.05 μm. Then, a thermal recording medium was produced using this transfer foil in the same manner as in Example 1. The print recording portion had a center line average roughness Ra of 0.05 μm. The transfer substrate peeled off after transfer had a center line average roughness Ra of 0.04 μm. As a result of the printing test, as shown in Table 1, since the surface roughness is too small, the head is in close contact, the thermal recording medium is not conveyed, the head conveying property is poor, printing is impossible, and the overall evaluation is poor. It became.
[0033]
<Comparative example 2>
Thermally destructive transfer foil and thermal recording in the same manner as in Example 3 except that the layer structure was the same as in Example 3 and the particle size of silica contained in the release resin layer of the transfer substrate was changed to 6 to 7 μm. A medium was made. The transfer substrate had a center line average roughness Ra of 1.85 μm, and the print recording portion had a center line average roughness Ra of 1.77 μm. The transfer substrate peeled off after transfer had a center line average roughness Ra of 1.73 μm. As a result of the printing test, as shown in Table 1, the head transportability was good, but the printing state was too large for the surface roughness, so that the head touch deteriorated and heat could not be transferred sufficiently, and the printing sensitivity was low. Due to the decrease, the printing was unclear and difficult to read, resulting in poor printing. As a result, the overall evaluation was poor.
[0034]
[Table 1]

[0035]
【The invention's effect】
(1) Heat-sensitive fracture transfer of the present invention On foil Therefore, by roughening the surface of the print recording part, the contact area with the thermal head can be reduced and the coefficient of friction can be reduced, so that good head transportability can be ensured without lowering the print sensitivity, and heat sensitivity. There is no defective conveyance of the recording medium, and further no printing defect caused by this. Further, the thermal head is not damaged due to poor conveyance, and the thermal head can be used up to the original durable life of the head.
In addition, since the surface of the print recording unit becomes rough, a self-cleaning effect can be obtained in which the head residue attached to the head during printing is removed by the surface irregularities of the print recording unit itself.
In addition, since the unevenness of the rough surface of the print recording unit surface scatters incident light, it can suppress the glossiness (glare feeling) of the metal thin film layer and give a matte feel. Thereby, the visibility of printing becomes more excellent. In addition, it becomes easy to cope with optical reading of a barcode or the like.
In particular, as the thermal destruction transfer foil, the print recording portion can be formed by transfer, so the material (heat resistance, etc.) and shape of the base material of the thermal recording medium are not selected, and any shape can be obtained at any position. A print recording unit can be provided. In addition, since the transportability of the head is not realized with only a lubricant such as silicone, it is possible to secure a good interlayer adhesion within the heat-sensitive recording layer as the transfer layer while maintaining stable peelability as a transfer foil. The head transportability can be secured.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing one embodiment of a heat-sensitive fracture transfer foil of the present invention.
FIG. 2 is a cross-sectional view showing another embodiment of the heat-sensitive fracture transfer foil of the present invention.
FIG. 3 is a cross-sectional view showing another embodiment of the heat-sensitive fracture transfer foil of the present invention.
[Fig. 4] Feeling Sectional drawing which shows one form of a thermal recording medium.
[Figure 5] Feeling The top view which shows the example of printing of a thermal recording medium.
[Explanation of symbols]
1 Transfer substrate
1a Main substrate
1b Releasable resin layer
2 Transfer layer
3 Resin layer
3a Release layer
3b protective layer
4 Metal thin film layer
5 Adhesive layer
6a Anchor layer
6b Anchor layer
7 Colored layer
8 Thermal recording layer
10 Print recording section
B base material
S Thermal Fracture Transfer Foil
M Thermal recording medium

Claims

At least as a transfer layer to a transfer substrate, a resin layer adjacent to the transfer substrate, the anchor layer, metallic thin film layer of tin formed by vacuum deposition, the anchor layer, the colored layer to obtain a thermal destruction recording medium having an adhesive layer in this order In this transfer foil, the thermal destruction transfer foil has a center line average roughness Ra of 0.1 to 1.5 μm on the transfer layer side surface of the transfer substrate.

The heat-sensitive fracture transfer foil according to claim 1, wherein the anchor layer is made of a vinyl chloride-vinyl acetate copolymer.