JP4048517B2 - Image recording medium containing a compound that generates acid by the action of heat or light - Google Patents

Description

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以下に本発明で有用な光の作用により酸を発生する、一般式（１）で表される化合物の具体例を例示するが本発明はこれらに限定されるものではない。
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本発明の化合物は、例えば前記ジャーナル・オブ・オーガニック・ケミストリー第３巻３１８〜３２７頁に記載の方法と同様にして、ＨＸ−（Ｌ）−Ｃ（Ｒ¹）（Ｒ²）−ＯＨに対してまず保護基Ｐを導入してＰＸ−（Ｌ）−Ｃ（Ｒ¹）（Ｒ²）−ＯＨを合成した後、塩基性条件下、酸ハライドと反応させることによって、得ることができる。
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熱の作用により酸を発生する前記化合物を含有する本発明の画像記録媒体をフォトンモード方式の画像記録媒体として利用する場合には光酸発生剤の添加が必須となる。
一方レーザーヒートモード記録方式の画像記録媒体として利用する場合には、熱の作用により酸を発生する前記化合物は、レーザー照射時の発熱によって酸を発生するため、別途熱酸発生剤を添加する必要はないが、熱酸発生効率が低い場合には高感度化することを目的としてレーザー照射時の熱の作用によって効率よく酸を発生する化合物を別途添加しても良い。
【００４６】
熱の作用により酸を発生する前記化合物とともに用いられる光酸発生剤としては本発明の光の作用で酸を発生する化合物も挙げられるが、その他には有機エレクトロニクス材料研究会（ぶんしん出版）編「イメージング用有機材料」ｐ１８７〜１９８（１９９３）に種々の例（非イオン性化合物としてハロゲン化水素を発生するハロゲン化物、スルホン酸を発生するスルホン化物、カルボン酸を発生するカルボニル化物、リン酸を発生するリン化合物等、イオン性化合物として各種オニウム塩等）が記載されている。本発明ではこれらのいずれも使用することができる。またこれらの光酸発生剤の感光域を広げる目的で種々増感剤（J.Polymer.Sci.,16 2441 (1978)等に例が記載されている）を添加することもできる。
本発明の熱の作用により酸を発生する化合物と併用することのできる光酸発生剤として、上記した本発明の光の作用により酸を発生する化合物以外で好ましい化合物の具体例を以下に示すが本発明はこれらに限定されるものではない。
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本発明の熱の作用により酸を発生する化合物をレーザーヒートモード方式の画像記録媒体に利用する場合、高感度化を目的として別途添加可能な熱酸発生剤として第１に挙げられるのはジアゾニウム、ヨードニウム、スルホニウム、ホスホニウムなどの芳香族オニウム化合物のスルホネート、ＰＦ^6-塩、ＡｓＦ^6-塩、ＳｂＦ^6-塩等である。これらは光の作用によって酸を発生する化合物でもあり、例としては光酸発生剤の例として記載したものが挙げられる。
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熱酸発生剤として第２に挙げられるのは酸のアンモニウム塩もしくはアミン錯体である。酸のアンモニウム塩は、酸をアンモニアまたはアミンで中和することによって合成できる。酸としては例えばｐ−トルエンスルホン酸、ベンゼンスルホン酸、１，８−ナフタレンジスルホン酸、ｐ−ニトロ安息香酸、２，４−ジクロロ安息香酸、フェニルホスホン酸、ＨＰＦ₆等を挙げることができる。また酸のアミン錯体としてはＢＦ₃・Ｅｔ₂Ｏとアミンを混合することによって得られる錯体等を挙げることができる。アミンは第１級、第２級、または第３級のアミンのいずれでも良く揮発性である場合が特に好ましい。例としてメチルアミン、エチルアミン、ｉｓｏ−プロピルアミン、ｔ−ブチルアミン、アニリン、ピリジン等を挙げることができる。
これらの酸のアンモニウム塩の具体例を以下に例示するが本発明はこれらに限定されるものではない。
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熱酸発生剤として第３に挙げられるのは、加熱によりβ−水素脱離して酸を発生する化合物である。この様な化合物としてはスルホン酸、カルボン酸もしくはりん酸のβ位に水素原子を有するアルキルエステル（例えばｔ−ブチルエステル、シクロヘキシルエステル、２−フェニルエチルエステル、４，５−ジヒドロ−２−メチルフラン−５−イルエステル、２−シクロヘキセニルエステルなど）、もしくは下記一般式２で示される化合物等を挙げることができる。
一般式２
ＹＯ−Ｎ＝ＣＨ−Ｚ
式中、ＹはＹＯＨで表されるスルホン酸、カルボン酸もしくはリン酸の残基を表す。Ｚは置換もしくは無置換のアリール基を表し、炭素数は６〜６０が好ましく、例としては、フェニル基、２，４−ジメトキシフェニル基、１−ナフチル基、２−メトキシ−１−ナフチル基、２−クロロ−１−ナフチル基等を挙げることができる。
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加熱によってβ水素離脱することにより酸を発生する化合物の具体例を以下に示すが本発明はこれらに限定されるものではない。
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熱酸発生剤として第４に挙げられるのはスルホン酸、カルボン酸およびリン酸の２−ニトロベンジルエステル、あるいはベンゾインエステルである。これらは光によって酸を発生する化合物でもあり、例としては光酸発生剤の例として前記したものが挙げられる。
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本発明ではこれらの熱酸発生剤のいずれも使用することができるが、分解温度としては１３０℃〜３００℃の範囲にあるものが好ましく、特に好ましくは１５０℃〜２５０℃の範囲にある場合である。
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本発明の画像記録媒体は酸触媒の作用により極性溶媒やアルカリ溶媒に可溶化または不溶化させるという構造変化を利用した、いわゆるフォトレジストへの適用も可能であるが、酸触媒の作用により発色または消色する化合物と組み合わせることにより色像あるいはＵＶ画像形成型記録媒体への応用が可能である。
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本発明において、発生した酸の作用（以降、単に酸の作用とも称す）により分子内もしくは分子間反応が促進され３６０〜９００ｎｍの範囲における吸収に変化を生じる化合物とは、中性〜塩基性の条件下で保存する限りにおいては安定であるが、酸が作用すると分子内、もしくは分子間反応の活性化エネルギーが下がり、加熱によって容易に反応が進行して前記範囲における吸収に変化を生じる化合物のことである。この際画像を形成するための加熱温度としては５０〜３００℃であることが好ましく、特に好ましくは８０〜１５０℃である。発色もしくは消色画像の形成反応と酸の発生は同時に行なうことができる。
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この様な吸収変化を伴う化合物は単一の化合物であってもよいし、２成分以上で構成されていてもよい。例えば、ディールスアルダー反応によって前記領域に消色画像を形成する化合物（例えば、９，１０−ジスチリルアントラセンと無水マレイン酸、テトラフェニルシクロペンタジエンとアクリル酸エステル等）、β−水素離脱によって共約系が拡張され前記領域に発色画像を形成する化合物（例えば１−アセトキシ−１，２−ジアリ−ルエタン、１−スルホキシ−１，２−ジアリールエタン等）、アルデヒドと活性メチレン化合物による脱水縮合（例えば写真用４等量マゼンタカプラーとｐ−メトキシシンナムアルデヒドからなる化合物等）、β−水素離脱によって共役系が拡張され前記領域に発色画像を形成する化合物（例えば１−アセトキシ−１，２−ジアリ−ルエタン、１−スルホキシ−１，２−ジアリールエタン等）、脱水縮合によって前記領域に発色画像を形成するアルデヒドと活性メチレン化合物の組み合わせ（例えば写真用４等量マゼンタカプラーとｐ−メトキシシンナムアルデヒド等）あるいは酸の作用で分解または離脱が促進される置換基によって置換されたアミノ基もしくは水酸基を分子内に有し、該置換基が外れることによって前記吸収域における吸収が変化する化合物等が挙げられる。また酸との接触により瞬時に発色する塩基性のロイコ染料（例えばジアリールフタリド類、フルオラン類ビスインドリルフタリド類、アリールインドリルフタリド類、アシルロイコジン類、ロイコオーラミン類、スピロピラン類、ローダミンラクタム類、ロイコトリアリールメタン類、ジアリールクロメン類等）も該画像形成媒体において使用することができる。
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これらの中でも本発明では、アミノ基もしくは水酸基の置換基が酸の作用によって分解もしくは離脱することにより吸収が変化する化合物を使用する。
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このようなアミノ基の置換基としてはアルコキシカルボニル基（例えばｔ−ブトキシカルボニル基、シクロヘキシルオキシカルボニル基、１，１−ジメチルプロピルオキシカルボニル基、１−メチル−１−フェニルエトキシカルボニル基、２−クロロエトキシカルボニル基等）、アシル基（例えばアセチル基、ベンゾイル基、２−ニトロベンゾイル基、４−クロロベンゾイル基、１−ナフトイル基等）またはホルミル基等が好ましい例として挙げられるが本発明では保存安定性と熱感度の観点からβ位に水素原子を有するアルコキシカルボニル基が特に有用である。
このような化合物としては、例えば米国特許第４，６０２，２６３号、第４，８２６，９７６号等に記載例がある。
【００６７】
以下に本発明に有用な前記置換基で置換されたアミノ基を有する化合物の具体例を示すが本発明はこれらに限定されるものではない。
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酸の作用により分解もしくは離脱する水酸基の置換基としては、β位に水素原子を有する２級もしくは３級のアルコキシカルボニル基（例えばｔ−ブトキシカルボニル基、イソプロピルオキシカルボニル基、１−フェニルエトキシカルボニル基、１，１−ジフェニルエトキシカルボニル基、２−シクロヘキセンオキシカルボニル基等）、シリル基（例えばトリメチルシリル基、トリエチルシリル基、ｔ−ブチルジメチルシリル基、ｔ−ブチルジフェニルシリル基、フェニルジメチルシリル基等）、アルコキシメチル基（例えばメトキシメチル基、エトキシメチル基、１−メトキシエチル基、１−フェノキシエチル基、１−メチル−１−メトキシエチル基等）およびβ位に水素原子を有する２級または３級のアルキル基（例えばテトラヒドロピラニル基、テトラヒドロフラニル基、４，５−ジヒドロ−２−メチルフラン−５−イル基、ｔ−ブチル基、２−シクロヘキセニル基等）が好ましい例として挙げられるが、本発明では特にβ位に水素原子を有する２級または３級のアルコキシカルボニル基が好ましい。
水酸基の置換基の分解によって吸収が変化する化合物としては米国特許第５，２４３，０５２号あるいは特開平９−２５３６０号等に記載例がある。
【００７５】
以下に本発明で有用な水酸基の置換基の分解によって前記領域における吸収が変化する化合物の具体例を例示するが本発明はこれらに限定されるものではない。
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本発明における色像形成型画像記録媒体は、前記分子内求核置換型酸発生剤、酸の作用により３６０〜９００ｎｍの吸収域に変化を生じる組成物および必要に応じて光または熱の作用により酸を発生する化合物を支持体上に塗布して作製される。この際これらのいずれかがポリマーである場合、あるいは塗布性の良いアモルファスである場合を除き、通常はバインダーを共存させる。また該画像記録媒体の保存安定性を高める目的で少量の塩基を添加したり、必要に応じて顔料、酸化防止剤、スティッキング防止剤等種々の添加剤を添加することもできる。また、画像形成層を保護するためにオーバーコート層を設けたり、支持体の裏面にバックコート層を設けても良い。なお、画像形成層と支持体との間に単層あるいは複数層の顔料あるいは樹脂からなるアンダーコート層を設けるなど、感熱記録材料等における種々の公知技術を用いることもできる。
【００８６】
また前記分子内求核置換型酸発生剤の添加量は酸の作用により吸収変化を伴う化合物の種類によっても異なるが、一般に吸収変化を伴う化合物に対して０．１〜２０当量の範囲であることが好ましく、特に好ましくは０.５〜５当量の場合である。
【００８７】
塩基を添加する場合には有機塩基が好ましく、例えばグアニジン誘導体（例えば１，３−ジフェニルグアニジン、１，３−ジメチルグアニジン、１，３−ジブチルグアニジン、１−ベンジルグアニジン、１，１，３，３−テトラメチルグアニジン等）、アニリン誘導体（例えばアニリン、ｐ−ｔ−ブチルアニリン、Ｎ，Ｎ’−ジメチルアニリン、Ｎ，Ｎ’−ジブチルアニリン、トリフェニルアミン等）、アルキルアミン誘導体（例えばトリブチルアミン、オクチルアミン、ラウリルアミン、ベンジルアミン、ジベンジルアミン等）、およびヘテロ環化合物（例えばＮ，Ｎ’−ジメチルアミノピリジン、１，８−ジアザビシクロ［５．４．０］−７−ウンデセン、トリフェニルイミダゾール、ルチジン、２−ピコリン等）が好ましい例として挙げられる。これらの塩基は酸発生剤に対して０．０１〜１００ｍｏｌ％添加することが好ましく、特に好ましくは０．１〜２０ｍｏｌ％添加する場合である。
【００８８】
バインダーとしては、ゼラチン、カゼイン、デンプン類、ヒドロキシエチルセルロース、カルボキシメチルセルロース、ポリビニルアルコール、ポリアクリルアミド、エチレン−無水マレイン酸コポリマー等の水溶性バインダー、およびポリビニルブチラール、トリアセチルセルロース、ポリスチレン、アクリル酸メチル−ブタジエンコポリマー、アクリロニトリル−ブタジエンコポリマー等の水不溶性バインダーのいずれも用いることができる。
【００８９】
顔料を添加する場合には、ケイソウ土、タルク、カオリン、焼成カオリン、酸化チタン、酸化ケイ素、炭酸マグネシウム、炭酸カルシウム、水酸化アルミニウム、尿素−ホルマリン樹脂等が例として挙げられる。
【００９０】
その他の添加剤としては、ベンゾフェノン系、ベンゾトリアゾール系等の紫外線吸収剤、ステアリン酸亜鉛、ステアリン酸カルシウム等の高級脂肪酸金属塩からなるヘッド摩耗およびスティッキング防止剤、パラフィン、酸化パラフィン、ポリエチレン、酸化ポリエチレン、カスターワックス等のワックス類等が挙げられ必要に応じて添加することができる。
【００９１】
本発明の画像記録媒体に用いられる支持体としては、上質紙、バライタ紙、コート紙、キャストコート紙、合成紙等の紙類、ポリエチレン、ポリプロピレン、ポリエチレンテレフタレート、ポリエチレン−２，６−ナフチレンジカルボキシレート、ポリアリーレン、ポリイミド、ポリカーボネート、トリアセチルセルロース等のポリマーフィルム、ガラス、金属箔、不織布等を挙げることができる。本発明の画像記録媒体を利用して透過型の画像、例えばＯＨＰ用フィルムや製版用フィルム等の用途に供する場合には、透明な支持体が用いられる。また、製版フィルム用には、熱膨張率が小さく寸度安定性が良好で、かつ、ＰＳ版の感光域に吸収を持たない支持体が選ばれる。
【００９２】
本発明の画像記録媒体に対してヒートモードで画像記録を行う場合、画像形成手段としての加熱方法には、加熱されたブロックやプレートと接触させる方法、熱ローラーや熱ドラムと接触させる方法、ハロゲンランプや赤外ないし遠赤外ランプヒーターを照射させる方法、感熱プリンターの熱ヘッドで画像状に加熱する方法、レーザー光を照射する方法等があるが、製版材料用途等の高い解像度が要求される場合にはレーザー光を照射する方法が好ましい。またより少ない熱エネルギーで画像を形成させるために予め、本発明の感熱記録材料を適当な温度に加熱しておくこともできる。
【００９３】
レーザー光照射により画像を形成する場合には、レーザー光を熱エネルギーに変換するために、該レーザー光の波長の光を吸収する色素を存在させる必要がある。レーザー光源としては、エキシマレーザー、アルゴンレーザー、ヘリウムネオンレーザー、半導体レーザー、ガラス（ＹＡＧ）レーザー、炭酸ガスレーザー、色素レーザー等があるが、ヘリウムネオンレーザー、半導体レーザーおよびガラスレーザーが本発明に有用なレーザー光源である。その中でも装置が小型で安価なことから、半導体レーザーが特に有用である。半導体レーザーの発振波長は通常、６７０〜８３０ｎｍであり、該近赤外に吸収を持つ色素が用いられる。近赤外吸収色素としては、シアニン色素、スクアリリウム色素、メロシアニン色素、オキソノール色素、フタロシアニン色素等が用いられる。
【００９４】
本発明では前述の加熱方法により酸発生剤からイメージワイズに酸触媒を発生させた後、全面加熱することによって画像イメージを増幅させることができる。この際、全面加熱する温度は非画像部の酸発生剤の分解が起こらない温度であることが必須であり、また製版材料用途に共する場合にはベースの寸法安定性が保障される温度でなくてはいけない。本発明における熱現像温度としては６０〜１５０℃の範囲にあることが好ましく、特に好ましくは８０〜１２０℃の場合である。
【００９５】
本発明の画像記録媒体において光の作用によって酸を発生する化合物を添加する場合には、該酸発生剤、あるいは感光域を広げるために添加された増感剤の吸収波長に合わせてレーザー光源が選択される。レーザー露光後の熱現像に関しては熱酸発生剤を使用した場合と同様である。
【００９６】
【実施例】
以下に実施例を掲げ、本発明を更に詳しく説明するが本発明はこれらに限定されるものではない。
【００９７】
本発明の分子内求核置換型酸発生剤の代表的な合成例を以下に例示する。
合成例１；例示化合物Ａ−（１）の合成
【００９８】
【化３６】

【００９９】
１，４−ブタンジオール（１−１）５ｇをＴＨＦ５０ｍｌに溶解し，カリウム−ｔ−ブトキシド６．２３ｇを添加した。さらにこの溶液中に室温下でジ−ｔ−ブチルジカーボネート（１−２）１２．１ｇを加え２時間撹拌を行った。得られた溶液を水１００ｍｌに加え、さらに酢酸エチル２００ｍｌを加えて有機層を抽出した。さらに、有機層を２回水で洗浄し、硫酸マグネシウムにより乾燥させ、濃縮した。シリカゲルカラムクロマトグラフィーにより精製を行い化合物（１−３）を油状化合物として３ｇ得た。
^１ Ｈ−ＮＭＲ（ＣＤＣｌ₃）
δ（ｐｐｍ）；１．４９（ｓ，９Ｈ），１．７０（ｍ，４Ｈ），１．９６（ｂｒ，１Ｈ），３．６６（ｔ，２Ｈ），４．１０（ｔ，２Ｈ）
【０１００】
次に化合物（１−３）２ｇを塩化メチレン１０ｍｌに溶解し、トリエチルアミン１．５７ｍｌ、４−ジメチルアミノピリジン０．２８ｇ、およびトルエンスルホニルクロライド２．１６ｇを加え室温で２時間撹拌した。反応液を水１０ｍｌにあけ有機層を抽出した。さらに、有機層を２回水で洗浄し、硫酸マグネシウムにより乾燥させ、濃縮した。シリカゲルカラムクロマトグラフィーにより精製を行い例示化合物Ａ−（１）を無色透明の油状化合物として１．５ｇ得た。
^１ Ｈ−ＮＭＲ（ＣＤＣｌ₃）
δ（ｐｐｍ）；１．４８（ｓ，９Ｈ），１．７１（ｍ，４Ｈ），２．４８（ｓ，３Ｈ），４．００（ｔ，２Ｈ），４．０５（ｔ，２Ｈ），７．３４（ｄ，２Ｈ），７．８０（ｄ，２Ｈ）
【０１０１】
合成例２；例示化合物Ａ−（３）の合成
【０１０２】
【化３７】

【０１０３】
化合物（２−１）９．０１ｇをテトラヒドロフラン５０ｍｌに入れ、そこに水素化ナトリウムのオイル分散物（４ｇ、含有率６０％）を加えた。１時間撹拌した後、化合物（２−２）１５．６６ｇを加え、３時間撹拌した。その後、酢酸エチル７０ｍｌと水５０ｍｌを加え水層を分離した。さらに反応液を水で洗浄し、有機層を無水硫酸ナトリウムで乾燥した後濃縮した。得られた油状物をシリカゲルカラムクロマトグラフィー（溶出液：酢酸エチル／ヘキサン＝１／４（体積比））にて精製し化合物（２−３）を９．５ｇ得た。
次に化合物（２−３）６．３ｇを塩化メチレン５０ｍｌに溶かし、化合物（２−４）５．１７ｇと化合物（２−５）６．０８ｇを加えて５時間撹拌した。そこにヘキサンを加え、そのままシリカゲルカラムクロマトグラフィー（溶出液：酢酸エチル／ヘキサン＝１／５（体積比））にて精製し、例示化合物Ａ−（３）を得た（６．２ｇ、収率５５％）。
【０１０４】
^１ Ｈ−ＮＭＲ（ＣＤＣｌ₃）
δ（ｐｐｍ）；１．６５（４Ｈ）、３．５５（２Ｈ）、４．１（２Ｈ）、４．６（２Ｈ）、４．７５（２Ｈ）、５．５（１Ｈ）、５．９（１Ｈ）、６．８（１Ｈ）、７．３５（５Ｈ）、７．６（２Ｈ）、７．９（２Ｈ）
【０１０５】
合成例３；例示化合物Ａ−（５）の合成
【０１０６】
【化３８】

【０１０７】
化合物（３−１）１５．０７ｇをテトラヒドロフラン７０ｍｌに入れ、そこに水素化ナトリウムのオイル分散物４ｇ（含有率６０％）を加えた。１時間撹拌した後、化合物（３−２）１５．６６ｇを加え、３時間撹拌した。その後、酢酸エチル７０ｍｌと水５０ｍｌを加え水層を分離した。さらに反応液を水で洗浄し、有機層を無水硫酸ナトリウムで乾燥した後濃縮した。得られた油状物をシリカゲルカラムクロマトグラフィー（溶出液：酢酸エチル／ヘキサン＝１／５（体積比））にて精製し化合物（３−３）を８．４ｇ得た。
次に化合物（３−３）２．０４ｇを塩化メチレンに溶かし、化合物（３−４）２．６ｇと化合物（３−５）１．９１ｇを加えて５時間撹拌した。そこにヘキサンを加え、そのままシリカゲルカラムクロマトグラフィー（溶出液：酢酸エチル／ヘキサン＝１／１０（体積比））にて精製し、例示化合物Ａ−（５）を得た（２．３ｇ、収率６３％）。
【０１０８】
^１ Ｈ−ＮＭＲ（ＣＤＣｌ₃）
δ（ｐｐｍ）；−０．１（６Ｈ）、０．９５（９Ｈ）、１．６（４Ｈ）、２．５（３Ｈ）、３．６（２Ｈ）、４．１（２Ｈ）、７．４（２Ｈ）、７．８（２Ｈ）
【０１０９】
実施例１
以下に示す化合物をクロロホルムに溶解し、厚み１００μｍのポリエチレンテレフタレートフィルム上に塗布、乾燥して透明な感熱記録シートを作製した。ポリスチレンは和光純薬製ポリスチレンビーズ（直径；約３．２mm）を使用した。
【０１１０】
試料−１
例示化合物Ａ−（１） ２ｍｍｏｌ／ｍ²
例示化合物Ｃ−（１） １ｍｍｏｌ／ｍ²
ＩＲ色素 １１３ｍｇ／ｍ²
ポリスチレン ２．２ｇ／ｍ²
【０１１１】
試料−２
例示化合物Ａ−（３） ２ｍｍｏｌ／ｍ²
例示化合物Ｃ−（１） １ｍｍｏｌ／ｍ²
ＩＲ色素 １１３ｍｇ／ｍ²
ポリスチレン ２．２ｇ／ｍ²
【０１１２】
試料−３
例示化合物Ａ−（５） ２ｍｍｏｌ／ｍ²
例示化合物Ｃ−（１） １ｍｍｏｌ／ｍ²
ＩＲ色素 １１３ｍｇ／ｍ²
ポリスチレン ２．２ｇ／ｍ²
【０１１３】
参考試料−１
比較化合物 ２ｍｍｏｌ／ｍ²
例示化合物Ｃ−（１） １ｍｍｏｌ／ｍ²
ＩＲ色素 １１３ｍｇ／ｍ²
ポリスチレン ２．２ｇ／ｍ²
【０１１４】
参考試料−２
例示化合物Ｃ−（１） １ｍｍｏｌ／ｍ²
ＩＲ色素 １１３ｍｇ／ｍ²
ポリスチレン ２．２ｇ／ｍ²
【０１１５】
【化３９】

【０１１６】
＜画像記録のためのレーザー露光条件＞
Spectra Diode Labs No.SDL-2430（波長範囲：８００〜８３０ｎｍ）を８本合波して、４００ｍＷの出力にして、画像書き込み用レーザーとした。
このレーザーを用いて、ビーム系１６０μｍ、レーザー走査スピードを１．０ｍ／秒（走査中央部）、試料送りスピードを１５ｍｍ／秒、走査ピッチを８本／ｍｍに設定して、２２ｍｍ×９ｍｍの画像となるような露光を前述した試料に対して行った。この時の試料上のレーザーエネルギー密度は２．５ｍＪ／ｍｍ² であった。
【０１１７】
＜発色率の比較＞
本発明の試料−１〜３および参考試料−１，２について、レーザー未露光のサンプルおよびレーザー走査露光後のサンプルをそれぞれ１２０℃、２０秒の加熱条件で熱現像を行い３６５ｎｍにおける発色濃度を求め、例示化合物Ｃ−（１）が１００％発色した時の理論値との比較から発色率を算出した。得られた結果を表１に示す。
【０１１８】
【表１】

【０１１９】
いずれの試料もレーザー未露光のものを１２０℃で熱現像しても全く発色は認められなかった。また酸発生剤無添加の参考試料−２はレーザー露光後に熱現像を行っても全く発色は認められなかった。これに対して酸発生剤を添加した試料１〜３および参考試料−１はレーザー露光後に熱現像することにより例示化合物Ｃ−（１）の発色が認められた。特に本発明の酸発生剤を添加した試料１〜３は公知の酸発生剤（比較化合物）を添加した参考試料−２よりも発色感度が向上していることが分かる。
【０１２０】
また参考試料−１ではガスの発生によるヘイズが認められ、さらに熱現像により赤褐色のステインが認められたが、本発明の試料１〜３ではヘイズは少なく、ステインは全く認められなかった。
【０１２１】
実施例２
実施例１で用いた本発明の試料１〜３および参考試料−１，２について６０℃／湿度７０％／１０日の条件で保存した後、レーザー露光を行わず１２０℃／２０秒の熱現像を行った時の発色率を表２に示した。
【０１２２】
【表２】

【０１２３】
本発明の試料−１〜３および参考試料−２は全く発色が認められなかったのに対して、参考試料−２では発色が認められた。比較化合物は該保存条件で分解が起こっているのに対して、本発明の酸発生剤は安定であることが分かる。
【０１２４】
実施例３
以下に示す化合物をクロロホルムに溶解し、厚み１００μｍのポリエチレンテレフタレートフィルム上に塗布、乾燥して透明なシートを作製した。ポリスチレンは和光純薬製ポリスチレンビーズ（直径；約３．２mm）を使用した。
【０１２５】
試料−１
例示化合物Ａ−（５８） ２ｍｍｏｌ／ｍ²
例示化合物Ｃ−（５０） １ｍｍｏｌ／ｍ²
ポリスチレン ２．２ｇ／ｍ²
【０１２６】
参考試料−１
光酸発生剤ＡＧ−（７） ２ｍｍｏｌ／ｍ²
例示化合物Ｃ−（５０） １ｍｍｏｌ／ｍ²
ポリスチレン ２．２ｇ／ｍ²
【０１２７】
試料−１および参考試料−１に対してメタルハライドランプ（８０Ｗ／ｃｍ）を酸発生剤の吸収波長域に相当するエネルギーが約３０ｍｊ／ｃｍ²になるように照射したところ本発明の試料−１および参考試料−１はともにほぼ１００％の発色率を示した。
一方、本発明の試料−１および参考試料−１を暗所、６０℃、７０％ＲＨ、７ｄの保存条件で保存したところ、参考試料−１は完全に発色したのに対して本発明の試料−１は全く発色せず湿熱安定性に優れることが分かる。
【０１２８】
【発明の効果】
本発明に従い、保存時には安定であるが、熱の作用により酸を発生する新規な分子内求核置換型の酸発生剤を含有せしめることにより、活性と保存性を両立した画像記録媒体を得ることができる。また、光の作用により酸を発生する分子内求核置換型の酸発生剤を含有せしめることにより、保存性と活性を両立した画像記録媒体を得ることができる。[0001]
BACKGROUND OF THE INVENTION
  The present inventionFeverThe present invention also relates to a highly sensitive chemically amplified image recording medium containing a novel compound that generates an acid by the action of light.
[0002]
[Prior art]
A thermal recording material expresses an image area and a non-image area as a temperature difference distribution, such as melting transfer or sublimation transfer of a colorant, color development reaction between two components by heat melting or capsule destruction, change of optical characteristics by phase transition, etc. Many schemes have been devised. This type of thermal recording medium is widely used as an output material for various printers, word processors, facsimiles and the like because it has a dry and simple system and has the advantage of being maintenance-free. In recent years, with the advancement of laser recording apparatuses, application to optical discs and plate making materials has been studied.
[0003]
Conventionally, silver halide photosensitive materials that require wet processing have been used as the plate-making material, but the development of a dry process is desired because of the demand for simplification of the processing process and the problem of environmental contamination due to processing solutions, In recent years, several technical proposals using a thermal recording system have been made. Image recording using a laser is preferable from the viewpoint of resolution. For example, a method called dye ablation using a high-power laser has been developed, and recording materials thereof are disclosed in JP-A-7-164755, JP-A-149063, and JP-A-7. JP-A-8-48053, JP-A-8-72400, etc. disclose an image forming apparatus.
[0004]
In this system, an image dye is applied by laser irradiation from the dye layer side onto a recording material having an image dye coated on a support, a dye composition comprising a substance having absorption in the laser wavelength range (infrared absorbing substance) and a binder. Recording is performed. The energy imparted by the laser causes an abrupt local change in the imaging layer at the spot where the laser beam hits the material, thereby driving the material out of the layer. According to the above patent publication, this is not a complete physical change (eg melting, evaporation or sublimation), but a certain chemical change (eg bond breakage), not partial image dye removal. That is complete removal. In such a dye ablation method, a high-power laser is indispensable to increase the dye removal efficiency at the laser exposure site, and a dust collector is required to collect the removed dye. there were.
[0005]
As a system that does not require a dust collector, a description of an ablation transfer type image recording method using a laser as a heat source is disclosed in US Pat. No. 5,171,650. This system uses a dye donor sheet containing a dynamic release layer overlying an ablative carrier topcoat, and the image is transferred to another receiver sheet that is adjacently aligned. For this reason, there is a problem in that a sheet that becomes unnecessary after image recording becomes a waste material. Also in this case, a high-power laser is indispensable to increase the transfer efficiency. As described above, the conventional thermal recording system using ablation by laser requires a high-power laser, and there is a problem that dust and waste materials cannot be avoided.
[0006]
Japanese Patent Laid-Open No. 6-194781 discloses a system called “dry silver” developed as a thermal recording system that does not involve ablation using a laser. In this system, recording is performed with a laser on a recording material containing a silver source that can be thermally reduced, a silver ion reducing agent, and a photothermal conversion dye. This was insufficient for practical performance.
[0007]
US Pat. Nos. 4,602,263 and 4,826,976, as other thermal recording systems utilizing laser, describe compounds whose absorption changes by thermal decomposition of carbamate. No. 5,243,052 describes a compound that develops yellow color by thermal decomposition of a t-butoxycarbonyl group introduced into a hydroxyl group. These methods use an irreversible single molecule reaction and are preferable for extremely short time image recording using a laser. However, the sensitivity is insufficient and further enhancement of sensitivity has been desired.
[0008]
On the other hand, as a means for dramatically improving the photosensitivity of a photoresist, Japanese Patent Application Laid-Open No. 8-248561 proposes a compound having a new concept of growing an acid catalyst by the action of an acid catalyst. As such an acid-growing compound, the above-mentioned patent publication discloses an organic acid by β-elimination subsequent to acid-catalyzed decomposition of a compound, acetal, or ketal that generates an organic acid by electron transfer subsequent to decomposition of t-butyl ester or the like by an acid catalyst. Compounds that produce and compounds that produce organic acids by acid-catalyzed pinacol rearrangement are described.
[0009]
By incorporating these compounds together with a compound that changes the absorption characteristics by the action of an acid, a highly sensitive color image forming recording medium can be obtained. These compounds also have a function as an acid generator that generates an acid by the action of heat during laser heat mode image recording. In this case, it is not necessary to add an acid generator separately.
However, these compounds are practically insufficient from the viewpoint of achieving both sensitivity and storage stability, and also have the problem of generating stains or generating gas during decomposition, and color image forming type recording media. Improvement was necessary to apply to. Further, these acid proliferating agents are not so easy synthetically, and further improvements have been desired in this respect.
[0010]
As a compound included in the structure of the acid generator of the present invention, 1-methanesulfonyloxy-5- (α-tetrahydropyranyl) oxypentane is described in Journal of Organic Chemistry Vol. 53, pages 318-327. However, in this paper, it is only described as a synthetic intermediate of 5-[(α-tetrahydropyranyl) oxy] -1-iodopentane, and it is an image recording medium as an acid generator. There is no mention about the application.
[0011]
[Problems to be solved by the invention]
  The purpose of the present invention is primarily stable during storage,FeverBy providing a novel intramolecular nucleophilic substitution type acid generator that generates an acid by action, an image recording medium having both activity and storage stability is provided. It is an object of the present invention to provide an image recording medium having both storage stability and activity by incorporating an intramolecular nucleophilic substitution-type acid generator that generates water.
[0012]
[Means for Solving the Invention]
  The subject of this invention is shown below 1)-3This has been achieved by the present invention.
1)FeverOr has at least one substituent removed by the action of light, and generates an acid by an intramolecular nucleophilic substitution reaction following the removal of the substituent.It is represented by the following general formula (1)CompoundCompounds whose absorption changes due to decomposition or separation of amino or hydroxyl substituents by the acid generatedAn image recording medium comprising:
  General formula (1) P-X-L-C (R ¹ ) (R ² ) -OA
  In the formula, P represents a substituent removed by the action of heat or light, and X represents O, S, NR. ^Three (R ^Three Represents a hydrogen atom or a substitutable group), or CR ^Four R ^Five (R ^Four And R ^Five Represents a hydrogen atom or a substitutable group, which may be the same or different, L represents a linking group, R ¹ And R ² Represents a hydrogen atom or a substitutable group, which may be the same or different, and OA represents an acid residue represented by HOA.
[0015]
  2)A compound whose absorption changes,Compounds that change in the absorption range of 360 to 900 nm by intramolecular or intermolecular reaction due to the action of acidIs1)InThe image recording medium described.
[0017]
  31) characterized by containing an infrared absorbing materialOr 2)The image recording medium described in 1.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
  The present invention is described in detail below.
  Used in the present inventionFeverOr a compound that generates acid by the action of light,FeverOr has at least one substituent removed by the action of light, and generates an acid by an intramolecular nucleophilic substitution reaction following the removal of the substituent.Represented by the following general formula (1)A compound.From the compound represented by the general formula (1)When a small amount of acid is generated, the acid increases as the reaction proceeds, and the reaction is accelerated.
  General formula (1) P-X-L-C (R ¹ ) (R ² ) -OA
  In the formula, P represents a substituent removed by the action of heat or light, and X represents O, S, NR. ^Three (R ^Three Represents a hydrogen atom or a substitutable group), or CR ^Four R ^Five (R ^Four And R ^Five Represents a hydrogen atom or a substitutable group, which may be the same or different, L represents a linking group, R ¹ And R ² Represents a hydrogen atom or a substitutable group, which may be the same or different, and OA represents an acid residue represented by HOA.
[0019]
FeverAlternatively, the substituent removed by the action of light (hereinafter referred to as substituent P) is a hydroxyl group, mercapto group, amino group in this compound.baseIntroduced into a nucleophilic group to prevent intramolecular nucleophilic substitution during storage or in non-image areas,FeverAlternatively, since the substituent is decomposed and separated by the action of light, an acid can be generated by an intramolecular nucleophilic substitution reaction.
[0020]
  The substituent represented by P isFeverPreferred examples of the substituent removed by action include those introduced into an oxygen atom, such as an alkoxycarbonyl group (for example, t-butoxycarbonyl group, isopropyloxycarbonyl group, 1-phenylethoxycarbonyl group, 1, 1-diphenylethoxycarbonyl group, 2-cyclohexeneoxycarbonyl group, etc.), alkoxymethyl group (for example, methoxymethyl group, ethoxymethyl group, n-octyloxymethyl group, tetrahydropyranyl group, tetrahydrofuranyl group, 4,5-dihydro) -2-methylfuran-5-yl group), silyl groups (for example, trimethylsilyl group, triethylsilyl group, t-butyldimethylsilyl group, t-butyldiphenylsilyl group, phenyldimethylsilyl group), and hydrogen at the β-position Secondary or tertiary with atoms Examples include alkyl groups (for example, t-butyl group, 2-cyclohexenyl group) and the like, and those introduced into the sulfur atom include alkoxymethyl groups (for example, isobutoxymethyl group, tetrahydropyranyl group, etc.), alkoxycarbonyl groups. (Eg benzyloxycarbonyl group, p-methoxybenzyloxycarbonyl group etc.), acyl group (eg acetyl group, benzoyl group etc.), benzyl group (eg p-methoxybenzyl group, bis (4-methoxyphenyl) methyl group, tri Phenylphenyl group and the like, and those introduced into the nitrogen atom include alkoxycarbonyl groups (for example, t-butoxycarbonyl group, cyclohexyloxycarbonyl group, 2- (2-methyl) butoxycarbonyl group, 2- (2- Phenyl) propyloxycarbonyl group, 2-chloroethoxy As a group introduced into a carbon atom, for example, an acyl group (for example, acetyl group, benzoyl group, 2-nitrobenzoyl group, 4-chlorobenzoyl group, 1-naphthoyl group). Includes a tertiary alkoxycarbonyl group (such as a t-butoxycarbonyl group).
[0021]
Preferable examples when the substituent represented by P is a substituent that is removed by the action of light include nitrobenzyl group, dinitrobenzyl group, nitrobenzyloxycarbonyl as those introduced into the oxygen atom and sulfur atom. Group and nitrobenzyloxymethyl group and the like, and those introduced into the nitrogen atom include nitrobenzyloxycarbonyl group, nitrobenzyloxymethyl group and formyl group, and those introduced into the carbon atom as Examples thereof include a nitrobenzyloxycarbonyl group and a nitrobenzyloxymethyl group.
[0022]
In the intramolecular nucleophilic substitution reaction subsequent to the removal of these substituents, a form in which a 5- to 10-membered ring is formed is preferable, and a 5- to 6-membered ring is particularly preferably formed.
[0023]
The acid generated by the intramolecular nucleophilic substitution reaction is preferably an acid having a pKa <3, and sulfonic acids (for example, p-toluenesulfonic acid, benzenesulfonic acid, methanesulfonic acid, trifluoromethanesulfonic acid, etc.), carboxylic acids (P-nitrobenzoic acid, 2-chloro-4-nitrobenzoic acid, trifluoroacetic acid, trichloroacetic acid etc.), phosphinic acids (phenylphosphinic acid, p-nitrophenylphosphinic acid, diphenylphosphinic acid etc.), phosphonic acids (phenyl) Preferred examples include phosphonic acid and ethylphosphonic acid.
[0024]
  The acid generator of the present invention may form a polymer by linking a plurality of polymerizable groups introduced at substitutable positions.In the present invention, a compound whose absorption is changed by decomposition or elimination of a substituent of an amino group or a hydroxyl group by an acid generated by the acid generator,Application to image recording media using the fact that the hue changes due to the action of acid, which will be described laterAlthoughShaped polymerCompleteThus, coating properties are imparted without using a separate binder, which is advantageous for thinning the image recording layer. Moreover, since the acid diffusivity is controlled, it is advantageous from the viewpoint of image quality. The molecular weight of the polymer is preferably in the range of 1,000 to 1,000,000, particularly preferably in the range of 2,000 to 300,000. In this case, it may be a homopolymer or a copolymer with another monomer.
[0025]
Further, by using a copolymer of an acid generator and a compound that develops or decolors by the action of an acid described below, high sensitivity can be expected in the sense that an acid is generated in the very vicinity of a leuco dye or the like. In this case, the copolymerization ratio of the leuco dye / acid generating site is preferably in the range of 100/1 to 1/20, particularly preferably in the range of 20/1 to 1/5.
[0026]
Below, each group other than P of General formula (1) is demonstrated.
[0027]
In the general formula (1), L represents a linking group, and the shortest linking chain connecting X and C is preferably composed of 3 to 8 atoms, particularly preferably composed of 3 to 4 atoms. Is the case. Preferred examples of these atoms include a carbon atom (which may have a possible substituent), an oxygen atom, a sulfur atom, and a nitrogen atom (which may have a possible substituent). They may be linked to form a ring.
[0028]
R in the general formula (1)¹And R²Represents a hydrogen atom or a substituent, which may be the same or different. Preferred examples of the substituent include an alkyl group (including those having a substituent. C 1-60 are preferable. For example, a methyl group , Ethyl group, n-propyl group, trifluoromethyl group, etc.), aryl group (including those having a substituent, preferably 6 to 60 carbon atoms. For example, phenyl group, naphthyl group, p-methoxyphenyl group, p- Chlorophenyl group, etc.), particularly preferably R¹And R²Are both hydrogen atoms.
[0029]
X in the general formula (1) is O, S, NR.^Three(R^ThreeRepresents a hydrogen atom or a substitutable group, and examples of the substituent include R¹And R²For example) or CR^FourR^Five(R^FourAnd R^FiveRepresents a hydrogen atom or a substitutable group, which may be the same or different, and examples of the substituent include R¹And R²And examples thereof are preferably O or S, and particularly preferably O.
[0030]
In the general formula (1), OA represents an acid residue represented by HOA. Preferred examples of HOA are as described above for the acid generated by the intramolecular nucleophilic substitution reaction. The acid generation efficiency of the compound represented by the general formula (1) can be controlled by the substituent P, the linking group L, and the pKa of the generated acid (AOH).
[0031]
  Useful in the present invention belowFeverGenerates acid by actionRepresented by the general formula (1)Although the specific example of a compound is illustrated, this invention is not limited to these.
[0032]
[Chemical 1]

[0033]
[Chemical formula 2]

[0034]
[Chemical Formula 3]

[0035]
[Formula 4]

[0036]
[Chemical formula 5]

[0037]
[Chemical 6]

[0038]
[Chemical 7]

[0039]
[Chemical 8]

[0040]
  In the following, acid is generated by the action of light useful in the present invention.Represented by the general formula (1)Although the specific example of a compound is illustrated, this invention is not limited to these.
[0041]
[Chemical 9]

[0042]
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[0043]
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[0044]
The compound of the present invention is prepared in the same manner as described in, for example, the Journal of Organic Chemistry Vol. 3, pages 318-327, HX- (L) -C (R¹) (R²) -OH is first introduced with a protecting group P to produce PX- (L) -C (R¹) (R²) -OH can be synthesized and then reacted with an acid halide under basic conditions.
[0045]
FeverWhen the image recording medium of the present invention containing the compound that generates an acid by action is used as a photon mode type image recording medium, the addition of a photoacid generator is essential.
  On the other hand, when used as an image recording medium for laser heat mode recording,FeverThe compound that generates an acid by action generates an acid due to heat generated during laser irradiation, so it is not necessary to add a separate thermal acid generator. However, if the thermal acid generation efficiency is low, the sensitivity should be increased. For the purpose, a compound that efficiently generates an acid by the action of heat during laser irradiation may be added separately.
[0046]
FeverExamples of the photoacid generator used together with the above-mentioned compound that generates acid by action include compounds that generate acid by the action of light according to the present invention, but in addition, “Imaging” edited by Organic Electronics Materials Research Group (Bunshin Publishing) Organic materials for p.187-198 (1993), various examples (halides that generate hydrogen halide, sulfonates that generate sulfonic acid, carbonylates that generate carboxylic acid, and phosphoric acid as nonionic compounds. Various onium salts and the like are described as ionic compounds such as phosphorus compounds. Any of these can be used in the present invention. Various sensitizers (examples are described in J. Polymer. Sci., 16 2441 (1978), etc.) may be added for the purpose of extending the photosensitive area of these photoacid generators.
  Of the present inventionFeverSpecific examples of preferable compounds other than the compound that generates an acid by the action of light of the present invention described above as a photoacid generator that can be used in combination with a compound that generates an acid by action are shown below. It is not limited.
[0047]
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[0048]
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[0049]
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[0050]
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[0051]
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[0052]
  Of the present inventionFeverWhen a compound that generates an acid by action is used in a laser heat mode image recording medium, the first examples of thermal acid generators that can be added separately for the purpose of increasing sensitivity are diazonium, iodonium, sulfonium, phosphonium. Sulfonates of aromatic onium compounds such as PF^6-Salt, AsF^6-Salt, SbF^6-Such as salt. These are also compounds that generate an acid by the action of light, and examples thereof include those described as examples of photoacid generators.
[0053]
A second example of the thermal acid generator is an ammonium salt of an acid or an amine complex. The ammonium salt of the acid can be synthesized by neutralizing the acid with ammonia or an amine. Examples of the acid include p-toluenesulfonic acid, benzenesulfonic acid, 1,8-naphthalenedisulfonic acid, p-nitrobenzoic acid, 2,4-dichlorobenzoic acid, phenylphosphonic acid, HPF₆Etc. As the amine complex of acid, BF_Three・ Et₂The complex etc. which are obtained by mixing O and an amine can be mentioned. The amine may be any of primary, secondary, and tertiary amines and is particularly preferably volatile. Examples include methylamine, ethylamine, iso-propylamine, t-butylamine, aniline, pyridine and the like.
Specific examples of the ammonium salts of these acids are illustrated below, but the present invention is not limited thereto.
[0054]
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[0055]
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[0056]
A third example of the thermal acid generator is a compound that generates an acid by elimination of β-hydrogen by heating. Such compounds include alkyl esters having a hydrogen atom at the β-position of sulfonic acid, carboxylic acid or phosphoric acid (eg t-butyl ester, cyclohexyl ester, 2-phenylethyl ester, 4,5-dihydro-2-methylfuran). -5-yl ester, 2-cyclohexenyl ester, etc.), or a compound represented by the following general formula 2.
General formula 2
YO-N = CH-Z
In the formula, Y represents a sulfonic acid, carboxylic acid or phosphoric acid residue represented by YOH. Z represents a substituted or unsubstituted aryl group, and preferably has 6 to 60 carbon atoms. Examples include a phenyl group, a 2,4-dimethoxyphenyl group, a 1-naphthyl group, a 2-methoxy-1-naphthyl group, A 2-chloro-1-naphthyl group can be exemplified.
[0057]
Specific examples of the compound that generates an acid by releasing β hydrogen by heating are shown below, but the present invention is not limited thereto.
[0058]
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[0059]
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[0060]
A fourth example of the thermal acid generator is 2-nitrobenzyl ester or benzoin ester of sulfonic acid, carboxylic acid and phosphoric acid. These are compounds that generate an acid by light, and examples thereof include those described above as examples of the photoacid generator.
[0061]
In the present invention, any of these thermal acid generators can be used, but the decomposition temperature is preferably in the range of 130 ° C to 300 ° C, particularly preferably in the range of 150 ° C to 250 ° C. is there.
[0062]
The image recording medium of the present invention can be applied to a so-called photoresist utilizing a structural change in which it is solubilized or insolubilized in a polar solvent or an alkaline solvent by the action of an acid catalyst. Application to a color image or UV image-forming type recording medium is possible by combining with a coloring compound.
[0063]
  In the present invention,OccurredAcid action(Hereafter referred to simply as the action of acid)Is a compound that promotes intramolecular or intermolecular reaction and causes a change in absorption in the range of 360 to 900 nm, as long as it is stored under neutral to basic conditions. Or, the activation energy of the intermolecular reaction is lowered, and the reaction easily proceeds by heating to cause a change in absorption in the above range. At this time, the heating temperature for forming an image is preferably 50 to 300 ° C, particularly preferably 80 to 150 ° C. The reaction for forming a color-developing or decoloring image and the generation of acid can be carried out simultaneously.
[0064]
A compound with such an absorption change may be a single compound or may be composed of two or more components. For example, a compound that forms a decolored image in the region by Diels-Alder reaction (eg, 9,10-distyrylanthracene and maleic anhydride, tetraphenylcyclopentadiene and acrylate ester, etc.) Is expanded to form a color image in the region (for example, 1-acetoxy-1,2-diarylethane, 1-sulfoxy-1,2-diarylethane, etc.), dehydration condensation with an aldehyde and an active methylene compound (for example, photographs) A compound comprising 4 equivalents of a magenta coupler and p-methoxycinnamaldehyde), a compound which expands the conjugated system by β-hydrogen elimination and forms a color image in the region (for example, 1-acetoxy-1,2-diallylethane) 1-sulfoxy-1,2-diarylethane, etc.) by dehydration condensation A combination of an aldehyde and an active methylene compound that forms a color image in the region (for example, 4 equivalents of a magenta photographic magenta coupler and p-methoxycinnamaldehyde) or a substituent that is decomposed or released by the action of an acid. Examples thereof include compounds having an amino group or a hydroxyl group in the molecule, and the absorption in the absorption region is changed by removal of the substituent. Basic leuco dyes that develop color instantly upon contact with acid (eg diarylphthalides, fluorans bisindolylphthalides, arylindolylphthalides, acyl leucodins, leucooramines, spiropyrans) , Rhodamine lactams, leucotriarylmethanes, diarylchromenes, etc.) can also be used in the image forming medium.
[0065]
  Among these, in the present invention,,Compounds whose absorption changes when amino or hydroxyl substituents are decomposed or released by the action of an acidUse.
[0066]
Such amino group substituents include alkoxycarbonyl groups (eg, t-butoxycarbonyl group, cyclohexyloxycarbonyl group, 1,1-dimethylpropyloxycarbonyl group, 1-methyl-1-phenylethoxycarbonyl group, 2-chloro Preferred examples include an ethoxycarbonyl group and the like, an acyl group (for example, an acetyl group, a benzoyl group, a 2-nitrobenzoyl group, a 4-chlorobenzoyl group and a 1-naphthoyl group), and a formyl group. An alkoxycarbonyl group having a hydrogen atom at the β-position is particularly useful from the viewpoints of properties and thermal sensitivity.
Examples of such compounds include those described in U.S. Pat. Nos. 4,602,263 and 4,826,976.
[0067]
Specific examples of the compound having an amino group substituted with the above-described substituent useful in the present invention are shown below, but the present invention is not limited thereto.
[0068]
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[0069]
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[0070]
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[0071]
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[0072]
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[0073]
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[0074]
Examples of the substituent of the hydroxyl group that decomposes or leaves by the action of an acid include a secondary or tertiary alkoxycarbonyl group having a hydrogen atom at the β-position (for example, t-butoxycarbonyl group, isopropyloxycarbonyl group, 1-phenylethoxycarbonyl group) , 1,1-diphenylethoxycarbonyl group, 2-cyclohexeneoxycarbonyl group, etc.), silyl group (for example, trimethylsilyl group, triethylsilyl group, t-butyldimethylsilyl group, t-butyldiphenylsilyl group, phenyldimethylsilyl group, etc.) , Alkoxymethyl groups (for example, methoxymethyl group, ethoxymethyl group, 1-methoxyethyl group, 1-phenoxyethyl group, 1-methyl-1-methoxyethyl group, etc.) and secondary or tertiary having a hydrogen atom at the β-position Alkyl groups such as tetrahydropyra Nyl group, tetrahydrofuranyl group, 4,5-dihydro-2-methylfuran-5-yl group, t-butyl group, 2-cyclohexenyl group and the like are preferable examples. A secondary or tertiary alkoxycarbonyl group having a hydrogen atom is preferred.
US Pat. No. 5,243,052 or Japanese Patent Application Laid-Open No. 9-25360 discloses examples of compounds whose absorption changes due to decomposition of a hydroxyl group substituent.
[0075]
Specific examples of the compound in which the absorption in the region is changed by the decomposition of the substituent of the hydroxyl group useful in the present invention are illustrated below, but the present invention is not limited thereto.
[0076]
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[0077]
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[0078]
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[0079]
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[0080]
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[0081]
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[0082]
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[0083]
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[0084]
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[0085]
The color image-forming image recording medium of the present invention comprises the above-described intramolecular nucleophilic substitution type acid generator, a composition that changes in the absorption range of 360 to 900 nm by the action of acid, and the action of light or heat as necessary. It is produced by applying a compound that generates an acid on a support. In this case, a binder is usually allowed to coexist unless any of these is a polymer or an amorphous material having good coatability. In addition, a small amount of a base can be added for the purpose of enhancing the storage stability of the image recording medium, and various additives such as a pigment, an antioxidant and an anti-sticking agent can be added as necessary. Further, an overcoat layer may be provided to protect the image forming layer, or a backcoat layer may be provided on the back surface of the support. Various known techniques in heat-sensitive recording materials can be used, such as providing an undercoat layer made of a single layer or a plurality of layers of pigment or resin between the image forming layer and the support.
[0086]
The amount of the intramolecular nucleophilic substitution-type acid generator added varies depending on the type of the compound accompanied by an absorption change due to the action of an acid, but generally ranges from 0.1 to 20 equivalents relative to the compound accompanied by an absorption change. Particularly preferred is the case of 0.5 to 5 equivalents.
[0087]
When adding a base, an organic base is preferable, for example, guanidine derivatives (for example, 1,3-diphenylguanidine, 1,3-dimethylguanidine, 1,3-dibutylguanidine, 1-benzylguanidine, 1,1,3,3). -Tetramethylguanidine, etc.), aniline derivatives (eg aniline, pt-butylaniline, N, N'-dimethylaniline, N, N'-dibutylaniline, triphenylamine etc.), alkylamine derivatives (eg tributylamine, Octylamine, laurylamine, benzylamine, dibenzylamine, etc.) and heterocyclic compounds (eg, N, N′-dimethylaminopyridine, 1,8-diazabicyclo [5.4.0] -7-undecene, triphenylimidazole) , Lutidine, 2-picoline, etc.) are preferable examples. It is. These bases are preferably added in an amount of 0.01 to 100 mol%, particularly preferably 0.1 to 20 mol%, based on the acid generator.
[0088]
Binders include water-soluble binders such as gelatin, casein, starches, hydroxyethyl cellulose, carboxymethyl cellulose, polyvinyl alcohol, polyacrylamide, ethylene-maleic anhydride copolymer, and polyvinyl butyral, triacetyl cellulose, polystyrene, methyl acrylate-butadiene. Any of water-insoluble binders such as a copolymer and acrylonitrile-butadiene copolymer can be used.
[0089]
In the case of adding a pigment, diatomaceous earth, talc, kaolin, calcined kaolin, titanium oxide, silicon oxide, magnesium carbonate, calcium carbonate, aluminum hydroxide, urea-formalin resin and the like can be mentioned as examples.
[0090]
Other additives include UV absorbers such as benzophenone and benzotriazole, head wear and anti-sticking agents composed of higher fatty acid metal salts such as zinc stearate and calcium stearate, paraffin, oxidized paraffin, polyethylene, polyethylene oxide, Examples thereof include waxes such as castor wax, which can be added as necessary.
[0091]
Examples of the support used in the image recording medium of the present invention include paper such as fine paper, baryta paper, coated paper, cast coated paper, synthetic paper, polyethylene, polypropylene, polyethylene terephthalate, polyethylene-2,6-naphthylene dicarboxylate. Examples thereof include polymer films such as rate, polyarylene, polyimide, polycarbonate, and triacetyl cellulose, glass, metal foil, and nonwoven fabric. When the image recording medium of the present invention is used for a transmissive image, for example, an OHP film or a plate making film, a transparent support is used. For the plate-making film, a support having a low coefficient of thermal expansion and good dimensional stability and having no absorption in the photosensitive area of the PS plate is selected.
[0092]
When image recording is performed on the image recording medium of the present invention in the heat mode, the heating method as the image forming means includes a method of contacting a heated block or plate, a method of contacting a heated roller or a thermal drum, a halogen There are a method of irradiating a lamp, an infrared or far-infrared lamp heater, a method of heating in an image form with a thermal head of a thermal printer, a method of irradiating a laser beam, etc., but high resolution is required for plate making materials. In some cases, a method of irradiating with laser light is preferred. Further, in order to form an image with less heat energy, the heat-sensitive recording material of the present invention can be heated to an appropriate temperature in advance.
[0093]
When an image is formed by laser light irradiation, a dye that absorbs light having the wavelength of the laser light needs to be present in order to convert the laser light into thermal energy. Examples of the laser light source include an excimer laser, an argon laser, a helium neon laser, a semiconductor laser, a glass (YAG) laser, a carbon dioxide gas laser, and a dye laser. A helium neon laser, a semiconductor laser, and a glass laser are useful in the present invention. Laser light source. Among them, a semiconductor laser is particularly useful because the apparatus is small and inexpensive. The oscillation wavelength of the semiconductor laser is usually 670 to 830 nm, and a dye having absorption in the near infrared is used. As the near-infrared absorbing dye, cyanine dyes, squarylium dyes, merocyanine dyes, oxonol dyes, phthalocyanine dyes and the like are used.
[0094]
In the present invention, an image image can be amplified by heating the entire surface after generating an acid catalyst imagewise from an acid generator by the heating method described above. At this time, it is essential that the temperature for heating the entire surface is a temperature at which decomposition of the acid generator in the non-image area does not occur, and in the case of use for plate making materials, a temperature at which the dimensional stability of the base is guaranteed. It must be. The heat development temperature in the present invention is preferably in the range of 60 to 150 ° C, particularly preferably 80 to 120 ° C.
[0095]
When a compound that generates an acid by the action of light is added to the image recording medium of the present invention, a laser light source is used in accordance with the absorption wavelength of the acid generator or a sensitizer added to widen the photosensitive area. Selected. The thermal development after the laser exposure is the same as when a thermal acid generator is used.
[0096]
【Example】
The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.
[0097]
The typical synthesis example of the intramolecular nucleophilic substitution type acid generator of this invention is illustrated below.
Synthesis Example 1; Synthesis of Exemplary Compound A- (1)
[0098]
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[0099]
5 g of 1,4-butanediol (1-1) was dissolved in 50 ml of THF, and 6.23 g of potassium tert-butoxide was added. Furthermore, 12.1 g of di-t-butyl dicarbonate (1-2) was added to this solution at room temperature, and the mixture was stirred for 2 hours. The obtained solution was added to 100 ml of water, and 200 ml of ethyl acetate was further added to extract the organic layer. Furthermore, the organic layer was washed twice with water, dried over magnesium sulfate and concentrated. Purification by silica gel column chromatography gave 3 g of compound (1-3) as an oily compound.
¹ H-NMR (CDCl_Three)
δ (ppm); 1.49 (s, 9H), 1.70 (m, 4H), 1.96 (br, 1H), 3.66 (t, 2H), 4.10 (t, 2H)
[0100]
  Next, 2 g of compound (1-3) was dissolved in 10 ml of methylene chloride, 1.57 ml of triethylamine, 0.28 g of 4-dimethylaminopyridine and 2.16 g of toluenesulfonyl chloride were added, and the mixture was stirred at room temperature for 2 hours. The reaction solution was poured into 10 ml of water and the organic layer was extracted. Furthermore, the organic layer was washed twice with water, dried over magnesium sulfate and concentrated. Purification by silica gel column chromatography gave 1.5 g of Exemplified Compound A- (1) as a colorless and transparent oily compound.
¹ H-NMR (CDCl_Three)
δ (ppm); 1.48 (s, 9H), 1.71 (m, 4H), 2.48 (s, 3H), 4.00 (t, 2H), 4.05 (t, 2H), 7.34 (d, 2H), 7.80 (d, 2H)
[0101]
Synthesis Example 2; Synthesis of Exemplary Compound A- (3)
[0102]
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[0103]
9.01 g of compound (2-1) was placed in 50 ml of tetrahydrofuran, and an oil dispersion of sodium hydride (4 g, content 60%) was added thereto. After stirring for 1 hour, 15.66 g of compound (2-2) was added and stirred for 3 hours. Thereafter, 70 ml of ethyl acetate and 50 ml of water were added to separate the aqueous layer. The reaction solution was further washed with water, and the organic layer was dried over anhydrous sodium sulfate and concentrated. The obtained oil was purified by silica gel column chromatography (eluent: ethyl acetate / hexane = 1/4 (volume ratio)) to obtain 9.5 g of compound (2-3).
Next, 6.3 g of the compound (2-3) was dissolved in 50 ml of methylene chloride, 5.17 g of the compound (2-4) and 6.08 g of the compound (2-5) were added, and the mixture was stirred for 5 hours. Hexane was added thereto and purified directly by silica gel column chromatography (eluent: ethyl acetate / hexane = 1/5 (volume ratio)) to obtain Exemplified Compound A- (3) (6.2 g, yield). 55%).
[0104]
¹ H-NMR (CDCl_Three)
δ (ppm); 1.65 (4H), 3.55 (2H), 4.1 (2H), 4.6 (2H), 4.75 (2H), 5.5 (1H), 5.9 (1H), 6.8 (1H), 7.35 (5H), 7.6 (2H), 7.9 (2H)
[0105]
Synthesis Example 3; Synthesis of Exemplary Compound A- (5)
[0106]
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[0107]
15.07 g of the compound (3-1) was put in 70 ml of tetrahydrofuran, and 4 g (content 60%) of an oil dispersion of sodium hydride was added thereto. After stirring for 1 hour, 15.66 g of compound (3-2) was added and stirred for 3 hours. Thereafter, 70 ml of ethyl acetate and 50 ml of water were added to separate the aqueous layer. The reaction solution was further washed with water, and the organic layer was dried over anhydrous sodium sulfate and concentrated. The obtained oil was purified by silica gel column chromatography (eluent: ethyl acetate / hexane = 1/5 (volume ratio)) to obtain 8.4 g of compound (3-3).
Next, 2.04 g of the compound (3-3) was dissolved in methylene chloride, 2.6 g of the compound (3-4) and 1.91 g of the compound (3-5) were added, and the mixture was stirred for 5 hours. Hexane was added thereto, and purified as it was by silica gel column chromatography (eluent: ethyl acetate / hexane = 1/10 (volume ratio)) to obtain Exemplified Compound A- (5) (2.3 g, yield). 63%).
[0108]
¹ H-NMR (CDCl_Three)
-0.1 (6H), 0.95 (9H), 1.6 (4H), 2.5 (3H), 3.6 (2H), 4.1 (2H), 7. 4 (2H), 7.8 (2H)
[0109]
Example 1
The following compounds were dissolved in chloroform, applied onto a polyethylene terephthalate film having a thickness of 100 μm, and dried to prepare a transparent thermosensitive recording sheet. As polystyrene, polystyrene beads made from Wako Pure Chemical Industries (diameter: about 3.2 mm) were used.
[0110]
Sample-1
Exemplary Compound A- (1) 2 mmol / m²
Exemplary Compound C- (1) 1 mmol / m²
IR dye 113mg / m²
Polystyrene 2.2g / m²
[0111]
Sample-2
Exemplary Compound A- (3) 2 mmol / m²
Exemplary Compound C- (1) 1 mmol / m²
IR dye 113mg / m²
Polystyrene 2.2g / m²
[0112]
Sample-3
Exemplary Compound A- (5) 2 mmol / m²
Exemplary Compound C- (1) 1 mmol / m²
IR dye 113mg / m²
Polystyrene 2.2g / m²
[0113]
Reference sample-1
Comparative compound 2 mmol / m²
Exemplary Compound C- (1) 1 mmol / m²
IR dye 113mg / m²
Polystyrene 2.2g / m²
[0114]
Reference sample-2
Exemplary Compound C- (1) 1 mmol / m²
IR dye 113mg / m²
Polystyrene 2.2g / m²
[0115]
Embedded image

[0116]
<Laser exposure conditions for image recording>
Eight Spectra Diode Labs No. SDL-2430 (wavelength range: 800 to 830 nm) was combined to obtain an output of 400 mW, which was used as an image writing laser.
Using this laser, an image of 22 mm x 9 mm is set with a beam system of 160 μm, a laser scanning speed of 1.0 m / second (scanning center), a sample feed speed of 15 mm / second, and a scanning pitch of 8 lines / mm. The above-described exposure was performed on the sample. The laser energy density on the sample at this time is 2.5 mJ / mm²   Met.
[0117]
<Color ratio comparison>
For samples -1 to 3 and reference samples -1 and 2 of the present invention, a laser unexposed sample and a sample after laser scanning exposure were thermally developed at 120 ° C. for 20 seconds, respectively, to determine the color density at 365 nm. The color development rate was calculated from comparison with the theoretical value when Example Compound C- (1) developed 100% color. The obtained results are shown in Table 1.
[0118]
[Table 1]

[0119]
In any sample, no color development was observed even when heat-developed at 120 ° C. without laser exposure. In addition, Reference Sample-2 to which no acid generator was added did not show any color development even after thermal development after laser exposure. On the other hand, Samples 1 to 3 and Reference Sample-1 to which an acid generator was added developed color of exemplary compound C- (1) by thermal development after laser exposure. In particular, it can be seen that Samples 1 to 3 to which the acid generator of the present invention has been added have improved color development sensitivity over Reference Sample-2 to which a known acid generator (comparative compound) has been added.
[0120]
Further, in Reference Sample-1, haze due to gas generation was observed, and reddish brown stain was observed by heat development, but in Samples 1 to 3 of the present invention, there was little haze and no stain was observed.
[0121]
Example 2
Samples 1 to 3 and Reference Samples 1 and 2 of the present invention used in Example 1 were stored under conditions of 60 ° C./humidity 70% / 10 days, followed by thermal development at 120 ° C./20 seconds without laser exposure. Table 2 shows the color development rate when the above was performed.
[0122]
[Table 2]

[0123]
In Samples 1-3 of the present invention and Reference Sample-2, no color development was observed, whereas in Reference Sample-2, color development was observed. It can be seen that the comparative compound is decomposed under the storage conditions, whereas the acid generator of the present invention is stable.
[0124]
Example 3
The compound shown below was dissolved in chloroform, applied onto a polyethylene terephthalate film having a thickness of 100 μm, and dried to prepare a transparent sheet. As polystyrene, polystyrene beads made from Wako Pure Chemical Industries (diameter: about 3.2 mm) were used.
[0125]
Sample-1
Exemplary Compound A- (58) 2 mmol / m²
Exemplary Compound C- (50) 1 mmol / m²
Polystyrene 2.2g / m²
[0126]
Reference sample-1
Photoacid generator AG- (7) 2 mmol / m²
Exemplary Compound C- (50) 1 mmol / m²
Polystyrene 2.2g / m²
[0127]
Compared to Sample-1 and Reference Sample-1, a metal halide lamp (80 W / cm) has an energy corresponding to the absorption wavelength region of the acid generator of about 30 mj / cm.²The sample-1 of the present invention and the reference sample-1 both exhibited a color development rate of almost 100%.
On the other hand, when the sample-1 of the present invention and the reference sample-1 were stored in the dark at 60 ° C., 70% RH, 7d, the sample of the present invention was completely developed while the reference sample-1 was completely colored. It can be seen that -1 is not colored at all and has excellent wet heat stability.
[0128]
【The invention's effect】
  According to the present invention, it is stable during storage,FeverBy incorporating a novel intramolecular nucleophilic substitution type acid generator that generates an acid by action, an image recording medium having both activity and storage stability can be obtained. Further, by including an intramolecular nucleophilic substitution type acid generator that generates an acid by the action of light, an image recording medium having both storability and activity can be obtained.

Claims (3)

Atsuma other has at least one substituent which is removed by the action of light, and a compound represented by the following general formula (1) which generates an acid by intramolecular nucleophilic substitution reaction subsequent to removal of said substituent An image recording medium comprising a compound whose absorption is changed by decomposition or elimination of a substituent of an amino group or a hydroxyl group by the generated acid .
General formula (1) P-X-L-C (R ¹ ) (R ² ) -OA
In the formula, P represents a substituent removed by the action of heat or light, X represents O, S, NR ³ (R ³ represents a hydrogen atom or a substitutable group), or CR ⁴ R ⁵ (R ⁴ And R ⁵ represents a hydrogen atom or a substitutable group, which may be the same or different, L represents a linking group, and R ¹ and R ² represent a hydrogen atom or a substitutable group. OA may be the same or different, and OA represents an acid residue represented by HOA. 2. The image recording medium according to claim 1, wherein the compound whose absorption changes is a compound which changes in an absorption range of 360 to 900 nm by an intramolecular or intermolecular reaction caused by the action of an acid. The image recording medium according to claim 1, further comprising an infrared absorbing material.