JP3843587B2 - Thermal recording material - Google Patents

Description

（但し、Ｒ¹、Ｒ²はそれぞれアルキル基、アルコキシ基、電子吸引性基を表す。ｍは０〜５の整数を表す。ｎは０〜４の整数を表す。Ａは２価の基を表す。）
【００１２】
本発明の一般式（１）で表される化合物において、Ａは２価の基を表す。Ａに属する基の代表的な例を下記式（５）及び（６）に示すが本発明はこれらに限定されるものではない。
【００１３】
【化６】

【００１４】
【化７】

【００１５】
さらに、下記一般式（２）、（３）、（４）で表される化合物は、より有用な化合物である。
【００１６】
【化８】

（但し、Ｒ³、Ｒ⁴はそれぞれアルキル基、アルコキシ基、電子吸引性基を表す。ｏは０〜５の整数を表す。ｐは０〜４の整数を表す。）
【００１７】
【化９】

（但し、Ｒ⁵、Ｒ⁶、Ｒ⁷はそれぞれアルキル基、アルコキシ基、電子吸引性基を表す。ｑは０〜５の整数を表す。ｒ、ｓは０〜４の整数を表す。）
【００１８】
【化１０】

（但し、Ｒ⁸、Ｒ⁹はそれぞれアルキル基、アルコキシ基、電子吸引性基を表す。ｔは０〜５の整数を表す。ｕは０〜４の整数を表す。ｖは２〜１２の整数を表す。）
【００１９】
ここで、Ｒ¹〜Ｒ⁹は該化合物を顕色剤として用いた場合に発色及び画像保存性を阻害しない置換基であれば良い。このうち顕色能力の安定性や発色感度の点から、炭素数１〜４のアルキル基、炭素数１〜４のアルコキシ基、電子吸引性基として塩素、臭素、フッ素等のハロゲン原子、ニトロ基、アルコキシカルボニル基、ニトリル基が望ましい。
【００２０】
本発明の化合物は分子内にヒドロキシ基を持たないが染料前駆体を発色させる顕色能を有するいわゆる非フェノール系顕色剤であり、フェニルスルファモイル基及び尿素構造を１分子内にそれぞれ２個有する化合物であることを特徴とするものである。これを用いて作製した感熱記録体は、記録部の耐可塑剤性や耐油性、耐水性等の画像保存性が大幅に向上する。その理由は明らかではないが、下記のように推定される。
【００２１】
一般に尿素構造を有する化合物は油や可塑剤、各種溶剤に難溶であることからこれらに曝されても溶出することがなく、これを顕色剤として用いた場合染料との解離による画像消失が起こらずに良好な画像保存性が得られる傾向がある。一方、本発明者らは、フェニルスルファモイル基も同様に画像保存性に寄与することを見出し、鋭意検討の結果、本発明の化合物が良好な画像保存性及び十分な顕色能を達成し得る優れた顕色剤であるという知見を得たものである。１分子内に有する尿素構造の数が増えればさらにその効果は増すと考えられるが、化合物の急激な融点又は分解点の上昇が起こりこれに伴って顕色能が低下することが懸念される。これに対しフェニルスルファモイル基は、尿素化合物の融点を低下させて顕色能を維持するように作用すると考えられ、両者が２個ずつ存在することにより、画像保存性及び顕色能のバランスの良い優れた品質性能が得られると推察される。
【００２２】
さらに本発明によれば、画像保存性が向上するだけでなく、白紙部の優れた耐熱地色安定性が得られる。これは本化合物が分子内に尿素構造を有していることが理由の１つであると考えられる。通常、尿素はケト型（−ＮＨＣ（＝Ｏ）ＮＨ−）で存在しているが、印字時には感熱ヘッド等で短時間ではあるが非常に大きな熱エネルギーが加わる。その際にエノール型（−Ｎ＝Ｃ（−ＯＨ）ＮＨ−）へと変化が生じ、ここで初めて顕色能が発揮されると推定される。一方、耐熱地色の安定性が求められる温度は９０〜１２０℃程度であり、この温度ではエノール型への変換は起らずに顕色能は発揮されない、つまり白紙部が発色して耐熱地色が悪化することはないと考えられる。加えて、本発明の化合物は従来のフェノール系顕色剤と比較して、融点が高いことも理由の１つであると推定される。感熱記録体には顕色剤の他に染料前駆体や増感剤など熱で融解し合う有機化合物が存在している。そのためこれら混合物の共融点は比較的低く、１００℃程度の加熱でも発色反応が進行して地色悪化する傾向があるが、より高融点の顕色剤はその恐れが小さいと考えられる。
【００２３】
【発明の実施の形態】
本発明の化合物は以下の方法で合成することができる。まず、アセトアミドベンゼンスルホニルクロライド化合物とアニリン化合物を反応させてアセトアミド−Ｎ−フェニルベンゼンスルホンアミド化合物を合成する。次に加水分解反応によりアセチル基を脱離してアミノ−Ｎ−フェニルベンゼンスルホンアミド化合物に導く。さらににアミノ−Ｎ−フェニルベンゼンスルホンアミド化合物を従来公知の方法（例えば新実験化学講座１４有機化合物の合成と反応［III］Ｐ．１６３１に記載の合成法）で尿素化することにより合成することができる。具体的には、アセトンやＴＨＦ等の不活性溶媒に溶解したジイソシアネートとアミノ−Ｎ−フェニルベンゼンスルホンアミドを不活性ガス雰囲気下で混合し、数分〜数時間室温で攪拌することにより、目的とする化合物を合成することができる。
【００２４】
また別法として、ジイソシアネート化合物とアニリン化合物２分子を反応させて尿素２量体を合成する。次に末端フェニル基をクロロ硫酸と反応させてジスルホニルクロライド化し、さらにアニリン化合物２分子と反応させて目的とする化合物を得ることができる。
【００２５】
本発明の化合物の原料としてジフェニルメタン−４，４’−ジイソシアネート＜商品名：ＭＤＩ＞やトリレン−２，４−ジイソシアネート＜２，４−ＴＤＩ＞、トリレン―２，６―ジイソシアネート＜２，６−ＴＤＩ＞、１，６−ヘキサメチレンジイソシアネート＜ＨＤＩ＞等を用いた場合、これらは塗料や接着剤、ポリウレタン原料として工業的に大量に生産されていることから、非常に容易かつ安価に入手可能である。また、製造する際も特殊な設備を必要とせず、高収率で合成することができる。そのため、本発明の顕色剤の製造コストは非常に安価になる利点がある。
【００２６】
本発明で用いられる化合物の具体例として以下の化合物を例示するが、本発明はこれらに限定されるものではない。
【００２７】
【化１１】

【００２８】
【化１２】

【００２９】
【化１３】

【００３０】
【化１４】

【００３１】
【化１５】

【００３２】
【化１６】

【００３３】
【化１７】

【００３４】
本発明の感熱記録体を製造するには、従来公知の種々の製造方法を利用することができる。具体的には、以下の様な方法で製造することができる。即ち、本発明の化合物、染料前駆体、増感剤をそれぞれボールミル、アトライター、サンドグラインダー等の粉砕機あるいは乳化機で微粒化し、各種填料及び各種添加剤を加え、水溶性バインダーの水溶液中で分散して塗料とし、これをエアーナイフコーター、ブレードコーター、ロールコーター等の各種コーター等で任意の支持体に塗工すると感熱記録体が得られる。本発明の化合物は単独又は２種類以上混合して使用しても良い。
【００３５】
本発明の感熱記録体に使用する染料前駆体としては、従来公知のものを使用することができる。以下に染料前駆体を例示するが、本発明はこれらに限定されるものではなく、またこれらを２種類以上混合して使用しても良い。
【００３６】
３，３−ビス（４−ジメチルアミノフェニル）−６−ジメチルアミノフタリド<商品名：ＣＶＬ＞、３−ジエチルアミノ−６−メチル−７−アニリノフルオラン＜ＯＤＢ＞、３−ジブチルアミノ−６−メチル−７−アニリノフルオラン＜ＯＤＢ−２＞、３−（Ｎ−イソアミル−Ｎ−エチルアミノ）−６−メチル−７−アニリノフルオラン＜Ｓ−２０５＞、３−ジエチルアミノ−７−ｍ−トリフルオロメチルアニリノフルオラン＜Ｂｌａｃｋ−１００＞、３−ジブチルアミノ−７−ｏ−クロロアニリノフルオラン＜ＴＨ−１０７＞、３−（Ｎ−シクロヘキシル−Ｎ−メチルアミノ）−６−メチル−７−アニリノフルオラン＜ＰＳＤ−１５０＞、３−ジエチルアミノ−７−アニリノフルオラン＜Ｇｒｅｅｎ−２＞、３，３−ビス（４−ジメチルアミノフェニル）フタリド＜ＭＧＬ＞、トリス［４−（ジメチルアミノ）フェニル］メタン＜ＬＣＶ＞、３，３−ビス（１−エチル−２−メチルインドール−３−イル）フタリド＜インドリルレッド＞、３−シクロヘキシルアミノ−６−クロロフルオラン＜ＯＲ−５５＞、３，３−ビス［２−（ｐ−ジメチルアミノフェニル）−２−（ｐ−メトキシフェニル）エテニル］−４，５，６，７−テトラクロロフタリド＜ＮＩＲ−Ｂｌａｃｋ＞、１，１，５，５−テトラキス（ｐ−ジメチルアミノフェニル）−３−メトキシ−１，４−ペンタジエン、１，１，５，５−テトラキス（ｐ−ジメチルアミノフェニル）−３−（ｐ−ジメチルアミノフェニル）−１，４−ペンタジエン。
【００３７】
本発明において、本発明の化合物と従来使用されている既知の顕色剤の１種又は２種以上を併用することができる。以下に顕色剤を例示するが、本発明はこれらに限定されるものではない。
【００３８】
４,４’−イソプロピリデンジフェノール、１，７−ジ（４−ヒドロキシフェニルチオ）−３，５−ジオキサヘプタン、４，４’−シクロヘキシリデンジフェノールなどのビスフェノール類、４−ヒドロキシ安息香酸ベンジル、４−ヒドロキシ安息香酸エチル、４−ヒドロキシ安息香酸ノルマルプロピル、４−ヒドロキシ安息香酸イソプロピル、４−ヒドロキシ安息香酸ブチルなどの４−ヒドロキシ安息香酸エステル類、４−ヒドロキシフタル酸ジメチル、４−ヒドロキシフタル酸ジイソプロピル、４−ヒドロキシフタル酸ジベンジル、４−ヒドロキシフタル酸ジヘキシルなどの４−ヒドロキシフタル酸ジエステル類、フタル酸モノベンジルエステル、フタル酸モノシクロヘキシルエステル、フタル酸モノフェニルエステル、フタル酸モノメチルフェニルエステルなどのフタル酸モノエステル類、ビス（４−ヒドロキシ−３−ｔｅｒｔ−ブチル−６−メチルフェニル）スルフィド、ビス（４−ヒドロキシ−２，５−ジメチルフェニル）スルフィド、ビス（４−ヒドロキシ−２−メチル−５−エチルフェニル）スルフィドなどのビスヒドロキシフェニルスルフィド類、４−ヒドロキシ−４’−イソプロポキシジフェニルスルホン、４−ヒドロキシ−４’−メチルジフェニルスルホン、４−ヒドロキシ−４’−ノルマルプロポキシジフェニルスルホンなどの４−ヒドロキシフェニルアリールスルホン類、４−ヒドロキシフェニルベンゼンスルホナート、４−ヒドロキシフェニル−ｐ−トリルスルホナート、４−ヒドロキシフェニル−ｐ−クロルベンゼンスルホナートなどの４−ヒドロキシフェニルアリールスルホナ−ト類、１，３−ジ［２−（４−ヒドロキシフェニル）−２−プロピル］ベンゼン、１，３−ジ［２−（４−ヒドロキシ−３−メチルフェニル）−２−プロピル］ベンゼンなどの１，３−ジ［２−（ヒドロキシフェニル）−２−プロピル］ベンゼン類、４−ヒドロキシベンゾイルオキシ安息香酸ベンジル、４−ヒドロキシベンゾイルオキシ安息香酸メチル、４−ヒドロキシベンゾイルオキシ安息香酸エチル、４−ヒドロキシベンゾイルオキシ安息香酸ノルマルプロピル、４−ヒドロキシベンゾイルオキシ安息香酸イソプロピル、４−ヒドロキシベンゾイルオキシ安息香酸ブチルなどの４−ヒドロキシベンゾイルオキシ安息香酸エステル類、ビス（３−ｔｅｒｔ−ブチル−４−ヒドロキシ−６−メチルフェニル）スルホン、ビス（３−エチル−４−ヒドロキシフェニル）スルホン、ビス（３−プロピル−４−ヒドロキシフェニル）スルホン、ビス（３−イソプロピル−４−ヒドロキシフェニル）スルホン、ビス（３−エチル−４−ヒドロキシフェニル）スルホン、ビス（４−ヒドロキシフェニル）スルホン、２−ヒドロキシフェニル−４’−ヒドロキシフェニルスルホン、ビス（３−クロル−４−ヒドロキシフェニル）スルホン、ビス（３−ブロモ−４−ヒドロキシフェニル）スルホンなどのビスヒドロキシフェニルスルホン類、ｐ−ｔｅｒｔ−ブチルフェノール、ｐ−フェニルフェノール、ｐ−ベンジルフェノール、１−ナフトール、２−ナフトールなどのフェノール類、安息香酸、ｐ−ｔｅｒｔ−ブチル安息香酸、トリクロル安息香酸、３−ｓｅｃ−ブチル−４−ヒドロキシ安息香酸、３−シクロヘキシル−４−ヒドロキシ安息香酸、３，５−ジメチル−４−ヒドロキシ安息香酸、テレフタル酸、サリチル酸、３−イソプロピルサリチル酸、３−ｔｅｒｔ−ブチルサリチル酸などの芳香族カルボン酸の金属塩。
【００３９】
染料前駆体と顕色剤を発色成分とする感熱記録体においては、発色感度を上げるために通常増感剤が使用される。以下に増感剤を例示するが、本発明はこれらに限定されるものではなく、またこれらを２種類以上混合して使用しても良い。
【００４０】
ステアリン酸、ステアリン酸アミド、パルミチン酸アミド、オレイン酸アミド、ベヘン酸、エチレンビスステアロアミド、ヤシ脂肪酸アミド、モンタン系ワックス、ポリエチレンワックス、フェニル−α−ナフチルカーボネート、ジ−ｐ−トリルカーボネート、ジフェニルカーボネート、４−ビフェニル−ｐ−トリルエーテル、ｐ−ベンジルビフェニル、ｍ−ターフェニル、トリフェニルメタン、１，１，３−トリス（２−メチル−４−ヒドロキシ−５−ｔｅｒｔ−ブチルフェニル）ブタン、１，２−ビス（３−メチルフェノキシ）エタン、１，２−ビスフェノキシエタン、１，２−ビス（４−メチルフェノキシ）エタン、１，４−ビスフェノキシブタン、１，４−ビスフェノキシブテン、２−ナフチルベンジルエ−テル、１，４−ジエトキシナフタリン、１，４−ジメトキシナフタリン、１−ヒドロキシ−２−ナフトエ酸フェニルエステル、１−ヒドロキシ−２−ナフトエ酸メチルエステル、２−ナフトエ酸フェニルエステル、ｐ−ベンジルオキシ安息香酸ベンジル、テレフタル酸ジベンジル、テレフタル酸ジメチル、１，１−ジフェニルエタノール、１，１−ジフェニル−２−プロパノール、１，３−ジフェノキシ−２−プロパノール、ｐ−（ベンジルオキシ）ベンジルアルコール、ノルマルオクタデシルカルバモイル−ｐ−メトキシカルボニルベンゼン、ノルマルオクタデシルカルバモイルベンゼン。
【００４１】
本発明においては、記録画像の安定性を向上させるため、各種助剤を添加してもよい。以下に助剤を例示するが、本発明はこれらに限定されるものではない。
【００４２】
ステアリン酸亜鉛、ステアリン酸アルミニウム、ステアリン酸カルシウム、パルミチン酸亜鉛、ベヘン酸亜鉛、ｐ−クロロ安息香酸金属塩（Ｚｎ、Ｃａ）、ｐ−ニトロ安息香酸金属塩（Ｚｎ、Ｃａ）、フタル酸モノベンジルエステル金属塩（Ｚｎ、Ｃａ）、４，４’−イソプロピリデン−ビス（３−メチル−６−ｔｅｒｔ−ブチル）フェノール。
【００４３】
本発明の感熱記録体に使用するバインダーとしては、従来、感熱記録の分野で公知のものを使用することができる。以下にバインダーを例示するが、本発明はこれらに限定されるものではない。
【００４４】
重合度が２０００以下の完全ケン化ポリビニールアルコール、部分ケン化ポリビニールアルコール、カルボキシ変性ポリビニールアルコール、アマイド変性ポリビニールアルコール、スルホン酸変性ポリビニールアルコール、その他の変性ポリビニールアルコール、ヒドロキシエチルセルロース、メチルセルロース、カルボキシメチルセルロース、アセチルセルロース等のセルロース誘導体、カゼイン、ゼラチン、スチレン−無水マレイン酸共重合体、スチレン−ブタジエン共重合体、スチレン、酢酸ビニール、アクリルアミド、アクリル酸エステル等の重合体及び共重合体、ポリアミド樹脂、シリコン樹脂、石油樹脂、テルペン樹脂、ケトン樹脂、クマロン樹脂、その他を挙げることができる。これら天然及び合成高分子物質は水またはアルコール等の有機溶剤に溶解して使用するほか、水等の媒体に乳化またはペースト状に分散した状態で使用できる。また、これらを２種類以上使用することもできる。
【００４５】
本発明の感熱記録体に使用する填料としては、クレー、焼成クレー、ケイソウ土、タルク、カオリン、炭酸カルシウム、塩基性炭酸マグネシウム、硫酸バリウム、炭酸バリウム、水酸化アルミニウム、酸化亜鉛、シリカ、水酸化マグネシウム、酸化チタン、尿素−ホルマリン樹脂、ポリスチレン樹脂、フェノール樹脂、その他の天然または合成の無機または有機填料を挙げることができるが、これらに限定されるものではない。これらを２種類以上使用することもできる。
【００４６】
添加剤としては、紫外線吸収剤、消泡剤、蛍光増白剤、耐水化剤、滑剤等を挙げることができるが、本発明はこれらに限定されるものではない。
【００４７】
本発明の感熱記録体に使用する染料前駆体及び顕色剤の量、その他の各種成分の種類及び量は、要求される性能及び記録適性に従って決定され特に限定されるものではないが、通常、染料前駆体１部に対して、顕色剤１〜８部、填料１〜２０部が好ましく、バインダーは全固形分中１０〜２５％が好ましい。
【００４８】
本発明の感熱記録体に使用される支持体としては、上質紙、中質紙、コート紙等の紙や、合成紙、プラスチックフィルム等を挙げることができるが、本発明はこれらに限定されるものではない。
【００４９】
さらに保存性を高める目的で、高分子物質等のオーバーコート層を感熱発色層上に設けることもできる。また、保存性及び感度を高める目的で、有機填料又は無機填料を含有するアンダーコート層を発色層と支持体の間に設けることもできる。
【００５０】
【実施例】
下記に実施例として本発明の化合物の合成例、ならびにその製造に適した出発物質の合成例、及びそれらを顕色剤として用いた感熱記録体の製造例を例示し本発明を具体的に説明する。また、反応物質やその他の使用成分は代表例として呈示したものであり、本発明の範囲内で上記に説明したように各種の変更が可能である。
【００５１】
−本発明の化合物の合成−
［出発物質の合成例］４−アミノ−Ｎ−フェニルベンゼンスルホンアミドの合成
４−アセトアミドベンゼンスルホニルクロライド３４．０ｇにメチルエチルケトン２５０ｍｌ、水３００ｍｌ、炭酸ナトリウム１８．６ｇを加えて溶解した。ここにアニリン１３．６ｇを添加して、室温で１時間反応させた。その後、４Ｎ−水酸化ナトリウム水溶液１７０ｍｌを加えて１６時間加熱還流して反応させた。エバポレータで溶媒を留去し、残渣に６Ｎ−塩酸を加えて酸性にし、生成する固体を濾取した。これを酢酸エチルで再結晶を行い、４−アミノ−Ｎ−フェニルベンゼンスルホンアミドの白色固体を２９．４ｇ（収率８１％）得た。
＜ＩＲスペクトル＞
(KBr錠剤法,cm^-1)
3420,3349,3294,3246,1638,1596,1495,1465,1435,1394,1319,1301,1220,1152,1093,1072,918,891,831,751,691,561
＜¹Ｈ−ＮＭＲスペクトル＞
(300MHz,DMSO-d₆,δ/ppm,TMS)
5.92(2H,s,NH₂),6.52(2H,d,J=9Hz,ArH),6.96(1H,t,J=7Hz,ArH),7.06(2H,d,J=8Hz,ArH),7.18(2H,t,J=8Hz,ArH),7.38(2H,d,J=8Hz,ArH),9.82(1H,s,NH)
＜¹³Ｃ−ＮＭＲスペクトル＞
(75MHz,DMSO-d₆,δ/ppm,TMS)
112.50,119.36,123.18,124.43,128.62,128.83,138.44,152.73
＜ＭＳスペクトル＞
(FAB-MS(M/Z))
249(M+H)⁺
【００５２】
［合成例１］４，４’−ビス（４−フェニルスルファモイルフェニルウレイド）ジフェニルメタン（Ａ−０１）の合成
４−アミノ−Ｎ−フェニルベンゼンスルホンアミド４．３７ｇをＴＨＦ３０ｍｌに溶解した。ここに窒素雰囲気下で、ＭＤＩ２．０ｇをＴＨＦ２０ｍｌに溶解した溶液を滴下し、６時間加熱還流して反応させた。反応終了後、エバポレータで溶媒を留去し、残渣を酢酸エチルで再結晶を行い、４，４’−ビス（４−フェニルスルファモイルフェニルウレイド）ジフェニルメタン（Ａ−０１）の白色固体を４．５４ｇ（収率７６％）得た。
＜分解点＞
２６０−２７０℃
＜ＩＲスペクトル＞
(KBr錠剤法,cm^-1)
3372,3190,1702,1594,1536,1512,1408,1313,1232,1152,1094,923,825,754,696,597,553
＜¹Ｈ−ＮＭＲスペクトル＞
(300MHz,DMSO-d₆,δ/ppm,TMS)
3.82(2H,s,CH₂),6.98(2H,t,J=7Hz,ArH),7.10(8H,d,J=7Hz,ArH),7.19(4H,t,J=8Hz,ArH),7.34(4H,d,J=8Hz,ArH),7.55(4H,d,J=9Hz,ArH),7.64(4H,d,J=9Hz,ArH),8.68(2H,s,NH),9.00(2H,s,NH),10.07(2H,s,SO₂NH)
＜¹³Ｃ−ＮＭＲスペクトル＞
(75MHz,DMSO-d₆,δ/ppm,TMS)
59.59,117.26,118.51,119.77,123.56,127.85,128.80,131.57,135.22,136.99,137.91,143.74,151.99,181.02
＜ＭＳスペクトル＞
(FAB-MS(M/Z))
747(M+H)⁺
【００５３】
［合成例２］２，４−ビス（４−フェニルスルファモイルフェニルウレイド）トルエン（Ａ−１３）の合成
４−アミノ−Ｎ−フェニルベンゼンスルホンアミド５．５０ｇをＴＨＦ３０ｍｌに溶解した。ここに窒素雰囲気下で、２，４−ＴＤＩ１．７５ｇをＴＨＦ２０ｍｌに溶解した溶液を滴下し、６時間加熱還流して反応させた。反応終了後、エバポレータで溶媒を留去し、残渣を酢酸エチルで再結晶を行い、２，４−ビス（４−フェニルスルファモイルフェニルウレイド）トルエン（Ａ−１３）の白色固体を２．８２ｇ（収率４２％）得た。
＜融点＞
２１８−２２０℃
＜ＩＲスペクトル＞
(KBr錠剤法,cm^-1)
3352,1695,1596,1537,1499,1450,1410,1313,1220,1153,1094,923,828,753,697,616,595,556
＜¹Ｈ−ＮＭＲスペクトル＞
(300MHz,DMSO-d₆,δ/ppm,TMS)
2.24(3H,s,CH₃),6.94-7.24(13H,m,ArH),7.53-7.67(8H,m,ArH),8.45(1H,s,NH),8.81(1H,s,NH),9.01(1H,s,NH),9.46(1H,s,NH)
＜¹³Ｃ−ＮＭＲスペクトル＞
(75MHz,DMSO-d₆,δ/ppm,TMS)
17.12,110.94.112.34.116.88.119.28,119.79.123.16.127.69.128.56,129.91,131.62,137.35,138.18,143.57,151.91,180.90
＜ＭＳスペクトル＞
(FAB-MS(M/Z))
671(M+H)⁺
【００５４】
［合成例３］１，６−ビス（４−フェニルスルファモイルフェニルウレイド）ヘキサン（Ａ−２５）の合成
４−アミノ−Ｎ−フェニルベンゼンスルホンアミド４．８７ｇをＴＨＦ３０ｍｌに溶解した。ここに窒素雰囲気下で、ＨＤＩ１．５０ｇをＴＨＦ２０ｍｌに溶解した溶液を滴下し、６時間加熱還流して反応させた。反応終了後、エバポレータで溶媒を留去し、残渣を酢酸エチルで再結晶を行い、１，６−ビス（４−フェニルスルファモイルフェニルウレイド）ヘキサン（Ａ−２５）の白色固体を３．６７ｇ（収率６２％）得た。
＜融点＞
２３７−２３９℃
＜ＩＲスペクトル＞
(KBr錠剤法,cm^-1)
3382,3343,3140,2930,2860,2272,1685,1594,1543,1497,1405,1321,1242,1151,1095,925,833,755,701,593,552
＜¹Ｈ−ＮＭＲスペクトル＞
(300MHz,DMSO-d₆,δ/ppm,TMS)
1.29-1.42(8H,m,CH₂),3.07(4H,q,J=6Hz,NCH₂),6.25(2H,t,J=5Hz,CONH),6.98(2H,t,J=7Hz,ArH),7.08(4H,d,J=8Hz,ArH),7.19(4H,t,J=8Hz,ArH),7.48(4H,d,J=9Hz,ArH),7.58(4H,d,J=9Hz,ArH),8.80(2H,s,ArNHCO),10.03(2H,s,NHSO₂)
＜¹³Ｃ−ＮＭＲスペクトル＞
(75MHz,DMSO-d₆,δ/ppm,TMS)
26.01,29.51,97.44,116.66,119.07,123.53,127.81,128.83,130.65,137.94,144.54,154.53,180.94
＜ＭＳスペクトル＞
(FAB-MS(M/Z))
671(M+H)⁺
【００５５】
―比較例の化合物の合成―
［合成例４］４，４’−ジフェニルスルファモイル−Ｎ，Ｎ’−ジフェニルウレア（Ｂ−０３）の合成
クロロ硫酸２５ｍｌを氷水バスに浸して冷却しつつ、Ｎ，Ｎ’−ジフェニルウレア１０ｇを徐々に添加した。その後室温にて４時間攪拌して反応させた。反応液を氷に投入し白色固体として４，４’−ジクロロスルホニル−Ｎ，Ｎ’−ジフェニルウレアを得た。これにアセトン１００ｍｌとピリジン１００ｍｌを加え溶解し、氷水バスに浸して冷却しつつアニリン８．７７ｇを滴下した。その後３０℃で２時間攪拌して反応させた。エバポレータで反応液中のアセトンを留去し、残渣に希塩酸を加えて酸性にした。これを酢酸エチルで抽出し溶媒留去した残渣をアセトン＋酢酸エチルで再結晶を行い、４，４’−ジフェニルスルファモイル−Ｎ，Ｎ’−ジフェニルウレア（Ｂ−０３）の白色固体を５．４１ｇ（収率２２％）得た。
＜分解点＞
２８３℃
＜ＩＲスペクトル＞
(KBr錠剤法,cm^-1)
3376,3305,3268,3189,1716,1594,1553,1541,1495,1407,1342,1322,1243,1215,1149,1095,933,913,900,830,757,697,664,563,543
＜¹Ｈ−ＮＭＲスペクトル＞
(300MHz,DMSO-d₆,δ/ppm,TMS)
7.00(2H,t,J=7Hz,ArH),7.10(4H,d,J=8Hz,ArH),7.22(4H,t,J=7Hz,ArH),7.58(4H,t,J=9Hz,ArH),7.71(4H,d,J=9Hz,ArH),9.23(2H,s,NHCONH),10.16(1H,s,NHSO₂)
＜¹³Ｃ−ＮＭＲスペクトル＞
(75MHz,DMSO-d₆,δ/ppm,TMS)
117.9,119.9,123.8,128.0,129.1,132.2,137.9,143.3,151.8
＜ＭＳスペクトル＞
(FAB-MS(M/Z))
523(M+H)⁺
【００５６】
−感熱記録体の製造−
［実施例１〜３］
下記組成物からなる感熱記録体を作製した。即ち、まず下記配合の染料分散液（Ａ液）と顕色剤分散液（Ｂ液）を各々サンドグラインダーにて平均粒子径１μｍまで磨砕した。

次いで、下記の割合でＡ液とＢ液及びカオリンクレーの分散液を混合して感熱塗料とした。
Ａ液：染料分散液 ９．２部
Ｂ液：顕色剤分散液 ３６．０部
カオリンクレー（５０％分散液） １２．０部
この感熱塗料を５０ｇ／ｍ²の基紙の片面に塗布量６．０−６．５ｇ／ｍ²になる様に塗布乾燥し、このシートをスーパーカレンダーで平滑度が５００−６００秒になる様に処理し、感熱記録体を作製した。
【００５７】
［比較例１〜３］
顕色剤分散液（Ｂ液）において、本発明の化合物に代えて下記に示す顕色剤を用いた以外は、実施例１〜３と同様にして感熱記録体を作製した。
４−ヒドロキシ−４’−イソプロポキシジフェニルスルホン（Ｂ−０１）
Ｎ，Ｎ’−ジフェニルウレア（Ｂ−０２）
４，４’−ジフェニルスルファモイル−Ｎ，Ｎ’−ジフェニルウレア（Ｂ−０３）
【００５８】
−感熱記録体の評価−
［発色方法］
作製した感熱記録体をＵＢＩプリンター２０１（ＵＢＩ社製）を使用し、印加エネルギー４５０ｍｊ／ｍｍ²で、作製した感熱記録体に記録を行った。次いで、その記録部及び白紙部の画像濃度をマクベス濃度計（ＲＤ−９１４、アンバーフィルターを使用）により測定した。これを試験サンプルとし、以下の試験を行った。
［耐可塑剤性試験］：試験サンプルを塩化ビニルフィルム（三菱樹脂（株）製ダイアラップ３００Ｇ）に接触させ、４０℃で２４時間放置し、記録部の画像残存濃度をマクベス濃度計で測定した。
［耐油性試験］：試験サンプルをサラダ油に１時間浸し、油を拭き取り、２４時間室温に放置し、記録部の画像残存濃度をマクベス濃度計で測定した。
［耐水性試験］：試験サンプルを水道水に２４時間浸し、３０℃で２時間乾燥し、記録部の画像残存濃度をマクベス濃度計で測定した。
［白紙部の耐熱地色試験］：試験サンプルを１００℃で３０分放置し、白紙部の濃度をマクベス濃度計で測定した。
画像記録部の画像保存性試験の結果を表１に、白紙部の耐熱地色試験の結果を表２に示す。表１では値が大きいほど画像保存性が、表２では値が小さいほど耐熱地色の安定性が優れていることを示す。
【００５９】
【表１】
表１．画像保存性試験の結果

【表２】
表２．耐熱地色試験の結果

【００６０】
表１及び２の結果から明らかなように、本発明の化合物を顕色剤として用いた実施例１〜３は、従来のフェノール系顕色剤を用いた比較例１やフェニルスルファモイル基を持たない尿素系顕色剤の比較例２、さらにはフェニルスルファモイル基を２つ有するが尿素構造を１つしか有さない尿素系顕色剤の比較例３に比べて、耐油性や耐可塑剤性が格段に向上しているのみならず耐水性も良好であり、かつ白紙部の耐熱地色安定性にも優れている。
【００６１】
【発明の効果】
本発明の化合物は、染料前駆体を発色せしめるに十分な能力を持っている。また、該化合物を顕色剤として用いた感熱記録体は、記録部の画像保存性及び白紙部の耐熱地色安定性に非常に優れているため、極めて有用なものである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat-sensitive recording material excellent in image storability of a recording part.
[0002]
[Prior art]
Generally, a heat-sensitive recording material is obtained by grinding and dispersing a colorless or light-colored dye precursor, which is an electron-donating compound, and a developer, which is an electron-accepting compound, into fine particles. A coating solution obtained by adding fillers, sensitizers, lubricants and other auxiliaries is applied to a support such as paper, synthetic paper, film, plastic, etc., such as thermal head, hot stamp, laser light, etc. Color recording is obtained by an instantaneous chemical reaction by heating. These thermal recording materials are applied to a wide range of fields such as measurement recorders, computer terminal printers, facsimiles, automatic ticket vending machines, and bar code labels.
[0003]
However, with the recent diversification of recording devices for thermal recording media and the advancement of high performance, the quality required for thermal recording media has become higher. In addition, with the widespread use of plain paper recording methods such as the electrophotographic method and the ink jet method, the thermal recording method is often compared with these plain paper recording methods. Therefore, for example, the stability of the recording part (image) of the thermal recording medium or the stability of the non-recording part (ground color) is required to approach the same level as that of the plain paper recording method. In particular, from the viewpoint of storage stability of a recorded image, a heat-sensitive recording material excellent in light resistance, oil resistance, water resistance, plasticizer resistance and the like is required.
[0004]
In particular, in order to improve oil resistance and plasticizer resistance, an epoxy compound described in JP-A-4-97887, an aziridine compound described in JP-A-4-113888, and JP-A-63-22683 in the thermosensitive coloring layer. Examples containing various metal salts described in the publication are known. However, the effect is insufficient.
[0005]
Further, in place of conventionally used phenol developers, so-called non-phenol developers have been developed that exhibit an acidic atmosphere that can develop a dye precursor without having a hydroxy group. So far, examples using urea, thiourea, phosphoric acid, phosphate ester, amide, urethane, etc. as non-phenolic developers have been disclosed, and when these are used as developers, conventional phenolic developers are disclosed. It is known that the image storability of the recording part is improved as compared with the colorant.
[0006]
Examples thereof include a carbonylsulfonamide compound described in JP-A-4-282291 and an organic phosphate compound described in JP-A-6-99666. One of the causes of decoloration of the color image is dissociation between the dye and the developer, but the non-phenol developer is less soluble in water, oil, plasticizer, etc. than the conventional phenol developer, It is considered that the image storage stability is improved. However, although there are some effects, the degree is still not enough.
[0007]
In addition, with respect to an example of using urea or a thiourea compound as a developer, a number of applications have been filed, including Japanese Patent Application Laid-Open No. 58-211496, for the purpose of developing a developer that is more effective in image preservation. Search for urea and thiourea derivatives has been conducted. For example, phenylurea or phenylthiourea compound described in JP-A-59-184694, thiourea dimer compound described in JP-A-60-145844, halogen-introduced diphenylthio described in JP-A-61-211085 Examples thereof include urea compounds and benzylthiourea compounds described in JP-A-5-185739. However, when heat-sensitive recording paper is produced using these, although there is an effect in a short-term plasticizer resistance and oil resistance test, an image disappearance is seen in a long-time test, and the effect of improving image storability is insufficient. is there. Further, JP-A-5-147357 discloses an example using a sulfonylurea compound as a developer. This exhibits excellent image storage stability, but has the disadvantages of ground color development in the plasticizer resistance test and slightly weak water resistance.
[0008]
Furthermore, there is an example in which a sulfonamide group is introduced into urea or a thiourea compound. The diphenylurea sulfonamide compound described in JP-A-7-304727 and JP-A-8-59603, JP-A-8-25810, and Examples thereof include diphenylthiourea sulfonamide compounds described in Kaihei 8-132737. These exhibit excellent image storability, but have the disadvantage of ground color development in the heat resistance test.
[0009]
[Problems to be solved by the invention]
An object of the present invention is to provide a heat-sensitive recording material having improved image storability of a recording portion and heat-resistant ground color stability of a blank paper portion.
[0010]
[Means for Solving the Problems]
As a result of intensive investigations to solve the above problems, the present researchers have shown that a compound having two phenylsulfamoyl groups and two urea structures in one molecule has an excellent function as a color developer for a thermal recording material. The inventors have found out that the present invention has been achieved and have completed the present invention. The compound in particular represented by the following general formula (1) are effectively used in the present invention.
[0011]
[Chemical formula 5]

(However, R ^1, R ² are each an alkyl group, an alkoxy group, .A .m representing an electron-withdrawing group is .n represents an integer of 0 to 5 represents an integer of 0 to 4 divalent groups To express.)
[0012]
In the compound represented by the general formula (1) of the present invention, A represents a divalent group. Representative examples of the group belonging to A are shown in the following formulas (5) and (6), but the present invention is not limited to these.
[0013]
[Chemical 6]

[0014]
[Chemical 7]

[0015]
Furthermore, the compounds represented by the following general formulas (2), (3), and (4) are more useful compounds.
[0016]
[Chemical 8]

(Wherein, R ^3, R ⁴ are each an alkyl group, an alkoxy group, an integer of .o 0-5 representing an electron-withdrawing group .p is an integer of 0-4.)
[0017]
[Chemical 9]

^{(Wherein, R 5, R 6, R} 7 are each an alkyl group, an alkoxy group, .r represents an integer of .q 0-5 representing an electron withdrawing group, s represents an integer of 0 to 4.)
[0018]
[Chemical Formula 10]

(Wherein, R ^8, R ⁹ are each an alkyl group, an alkoxy group, .v .t representing an electron-withdrawing group is .u represents an integer of 0 to 5 represents an integer of 0 to 4 integer from 2 to 12 Represents.)
[0019]
Here, R ^{1 to} R ⁹ may be any substituents that do not inhibit color development and image storage stability when the compound is used as a developer. Among these, from the viewpoint of stability of color developing ability and color development sensitivity, alkyl groups having 1 to 4 carbon atoms, alkoxy groups having 1 to 4 carbon atoms, halogen atoms such as chlorine, bromine and fluorine as electron-withdrawing groups, nitro groups An alkoxycarbonyl group and a nitrile group are desirable.
[0020]
The compound of the present invention is a so-called non-phenolic developer that does not have a hydroxy group in the molecule but has a color developing ability to develop a dye precursor, and each has two phenylsulfamoyl groups and two urea structures in one molecule. It is characterized by being a compound having one. A heat-sensitive recording material produced using this greatly improves image storability such as plasticizer resistance, oil resistance and water resistance of the recording part. The reason is not clear, but is estimated as follows.
[0021]
In general, a compound having a urea structure is hardly soluble in oils, plasticizers, and various solvents, so it does not elute even when exposed to these. When this is used as a developer, image loss due to dissociation from the dye will occur. There is a tendency that good image storability can be obtained without occurring. On the other hand, the present inventors have found that phenylsulfamoyl groups also contribute to image storability, and as a result of intensive studies, the compound of the present invention has achieved good image storability and sufficient color developing ability. It has been found that the developer is an excellent developer. The effect is considered to increase if the number of urea structures in one molecule increases, but there is a concern that the rapid melting point or decomposition point of the compound will increase and the color developing ability will decrease accordingly. In contrast, the phenylsulfamoyl group is thought to act to maintain the color developing ability by lowering the melting point of the urea compound, and the presence of both of them results in a balance between image storability and color developing ability. It is inferred that good quality performance with good quality can be obtained.
[0022]
Furthermore, according to the present invention, not only the image storability is improved, but also excellent heat resistant ground color stability of the white paper portion can be obtained. This is considered to be one of the reasons that this compound has a urea structure in the molecule. Usually, urea exists in the keto type (—NHC (═O) NH—), but very large heat energy is applied by a thermal head or the like during printing for a short time. At that time, a change to the enol type (—N═C (—OH) NH—) occurs, and it is estimated that the color developing ability is exhibited for the first time. On the other hand, the temperature at which the stability of the heat resistant ground color is required is about 90 to 120 ° C. At this temperature, the conversion to the enol type does not occur and the color developing ability is not exhibited. The color is not expected to deteriorate. In addition, the compound of the present invention is presumed to be one of the reasons that the melting point is higher than that of conventional phenol developers. In addition to the developer, the thermosensitive recording medium contains an organic compound that melts with heat, such as a dye precursor and a sensitizer. Therefore, the eutectic point of these mixtures is relatively low, and even when heated to about 100 ° C., the color development reaction tends to deteriorate and the ground color tends to deteriorate. However, it is considered that the higher melting point developer is less likely.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
The compound of the present invention can be synthesized by the following method. First, an acetamide benzenesulfonyl chloride compound and an aniline compound are reacted to synthesize an acetamide-N-phenylbenzenesulfonamide compound. Next, the acetyl group is eliminated by hydrolysis reaction and led to an amino-N-phenylbenzenesulfonamide compound. Furthermore, the amino-N-phenylbenzenesulfonamide compound is synthesized by ureation by a conventionally known method (for example, synthesis and reaction of new experimental chemistry course 14 organic compound and reaction [III] P.1631). Can do. Specifically, diisocyanate dissolved in an inert solvent such as acetone or THF and amino-N-phenylbenzenesulfonamide are mixed in an inert gas atmosphere and stirred at room temperature for several minutes to several hours, thereby achieving the purpose. Can be synthesized.
[0024]
As another method, a dimer is synthesized by reacting a diisocyanate compound and two molecules of an aniline compound. Next, the terminal phenyl group is reacted with chlorosulfuric acid to form disulfonyl chloride, and further reacted with two molecules of the aniline compound to obtain the target compound.
[0025]
Diphenylmethane-4,4′-diisocyanate <trade name: MDI>, tolylene-2,4-diisocyanate <2,4-TDI>, tolylene-2,6-diisocyanate <2,6-TDI as raw materials for the compounds of the present invention >, 1,6-hexamethylene diisocyanate <HDI> and the like are industrially produced in large quantities as paints, adhesives, and polyurethane raw materials, and can be obtained very easily and inexpensively. . In addition, no special equipment is required for the production, and it can be synthesized in a high yield. Therefore, there is an advantage that the production cost of the developer of the present invention is very low.
[0026]
The following compounds are illustrated as specific examples of the compounds used in the present invention, but the present invention is not limited thereto.
[0027]
Embedded image

[0028]
Embedded image

[0029]
Embedded image

[0030]
Embedded image

[0031]
Embedded image

[0032]
Embedded image

[0033]
Embedded image

[0034]
For producing the heat-sensitive recording material of the present invention, various conventionally known production methods can be used. Specifically, it can be produced by the following method. That is, the compound of the present invention, the dye precursor, and the sensitizer are each atomized with a pulverizer or an emulsifier such as a ball mill, attritor, and sand grinder, and various fillers and various additives are added, in an aqueous solution of a water-soluble binder. When a coating material is dispersed and coated on an arbitrary support with various coaters such as an air knife coater, a blade coater, and a roll coater, a heat-sensitive recording material is obtained. You may use the compound of this invention individually or in mixture of 2 or more types.
[0035]
As the dye precursor used in the heat-sensitive recording material of the present invention, conventionally known ones can be used. Examples of dye precursors are shown below, but the present invention is not limited to these, and two or more of these may be used in combination.
[0036]
3,3-bis (4-dimethylaminophenyl) -6-dimethylaminophthalide <trade name: CVL>, 3-diethylamino-6-methyl-7-anilinofluorane <ODB>, 3-dibutylamino-6 -Methyl-7-anilinofluorane <ODB-2>, 3- (N-isoamyl-N-ethylamino) -6-methyl-7-anilinofluorane <S-205>, 3-diethylamino-7- m-trifluoromethylanilinofluorane <Black-100>, 3-dibutylamino-7-o-chloroanilinofluorane <TH-107>, 3- (N-cyclohexyl-N-methylamino) -6 Methyl-7-anilinofluorane <PSD-150>, 3-diethylamino-7-anilinofluorane <Green-2>, 3,3-bis (4-dimethylamino) Nophenyl) phthalide <MGL>, tris [4- (dimethylamino) phenyl] methane <LCV>, 3,3-bis (1-ethyl-2-methylindol-3-yl) phthalide <indolyl red>, 3- Cyclohexylamino-6-chlorofluorane <OR-55>, 3,3-bis [2- (p-dimethylaminophenyl) -2- (p-methoxyphenyl) ethenyl] -4,5,6,7-tetra Chlorophthalide <NIR-Black>, 1,1,5,5-tetrakis (p-dimethylaminophenyl) -3-methoxy-1,4-pentadiene, 1,1,5,5-tetrakis (p-dimethylamino) Phenyl) -3- (p-dimethylaminophenyl) -1,4-pentadiene.
[0037]
In this invention, the compound of this invention and the 1 type (s) or 2 or more types of the conventionally used known color developer can be used together. Examples of the developer are shown below, but the present invention is not limited thereto.
[0038]
Bisphenols such as 4,4′-isopropylidenediphenol, 1,7-di (4-hydroxyphenylthio) -3,5-dioxaheptane, 4,4′-cyclohexylidenediphenol, 4-hydroxybenzoic acid 4-hydroxybenzoic acid esters such as benzyl, ethyl 4-hydroxybenzoate, normal propyl 4-hydroxybenzoate, isopropyl 4-hydroxybenzoate, butyl 4-hydroxybenzoate, dimethyl 4-hydroxyphthalate, 4-hydroxy 4-hydroxyphthalic acid diesters such as diisopropyl phthalate, dibenzyl 4-hydroxyphthalate, dihexyl 4-hydroxyphthalate, monobenzyl phthalate, monocyclohexyl phthalate, monophenyl phthalate, monomethyl phthalate Phthalic acid monoesters such as phenyl ester, bis (4-hydroxy-3-tert-butyl-6-methylphenyl) sulfide, bis (4-hydroxy-2,5-dimethylphenyl) sulfide, bis (4-hydroxy-) Bishydroxyphenyl sulfides such as 2-methyl-5-ethylphenyl) sulfide, 4-hydroxy-4′-isopropoxydiphenylsulfone, 4-hydroxy-4′-methyldiphenylsulfone, 4-hydroxy-4′-normal propoxy 4-hydroxyphenyl aryl sulfones such as diphenyl sulfone, 4-hydroxyphenyl benzene sulfonate, 4-hydroxyphenyl-p-tolyl sulfonate, 4-hydroxyphenyl-p-chlorobenzene sulfonate, and the like. Aryl sulfonates, 1,3-di [2- (4-hydroxyphenyl) -2-propyl] benzene, 1,3-di [2- (4-hydroxy-3-methylphenyl) -2-propyl 1,3-di [2- (hydroxyphenyl) -2-propyl] benzenes such as benzene, benzyl 4-hydroxybenzoyloxybenzoate, methyl 4-hydroxybenzoyloxybenzoate, ethyl 4-hydroxybenzoyloxybenzoate 4-hydroxybenzoyloxybenzoates such as normal propyl 4-hydroxybenzoyloxybenzoate, isopropyl 4-hydroxybenzoyloxybenzoate, butyl 4-hydroxybenzoyloxybenzoate, bis (3-tert-butyl-4- Hydroxy-6-methylphenyl) sulfone, bi (3-ethyl-4-hydroxyphenyl) sulfone, bis (3-propyl-4-hydroxyphenyl) sulfone, bis (3-isopropyl-4-hydroxyphenyl) sulfone, bis (3-ethyl-4-hydroxyphenyl) Sulfone, bis (4-hydroxyphenyl) sulfone, 2-hydroxyphenyl-4′-hydroxyphenylsulfone, bis (3-chloro-4-hydroxyphenyl) sulfone, bis (3-bromo-4-hydroxyphenyl) sulfone, etc. Bishydroxyphenyl sulfones, phenols such as p-tert-butylphenol, p-phenylphenol, p-benzylphenol, 1-naphthol, 2-naphthol, benzoic acid, p-tert-butylbenzoic acid, trichlorobenzoic acid, 3 -Sec-butyl-4- Metals of aromatic carboxylic acids such as hydroxybenzoic acid, 3-cyclohexyl-4-hydroxybenzoic acid, 3,5-dimethyl-4-hydroxybenzoic acid, terephthalic acid, salicylic acid, 3-isopropylsalicylic acid, 3-tert-butylsalicylic acid salt.
[0039]
In a heat-sensitive recording material having a dye precursor and a developer as color forming components, a sensitizer is usually used to increase the color developing sensitivity. Although a sensitizer is illustrated below, this invention is not limited to these, Moreover, you may use these in mixture of 2 or more types.
[0040]
Stearic acid, stearic acid amide, palmitic acid amide, oleic acid amide, behenic acid, ethylene bisstearamide, palm fatty acid amide, montan wax, polyethylene wax, phenyl-α-naphthyl carbonate, di-p-tolyl carbonate, diphenyl Carbonate, 4-biphenyl-p-tolyl ether, p-benzylbiphenyl, m-terphenyl, triphenylmethane, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,2-bis (3-methylphenoxy) ethane, 1,2-bisphenoxyethane, 1,2-bis (4-methylphenoxy) ethane, 1,4-bisphenoxybutane, 1,4-bisphenoxybutene, 2-naphthylbenzyl ether, 1,4-dietoki Naphthalene, 1,4-dimethoxynaphthalene, 1-hydroxy-2-naphthoic acid phenyl ester, 1-hydroxy-2-naphthoic acid methyl ester, 2-naphthoic acid phenyl ester, p-benzyloxybenzoic acid benzyl, terephthalic acid dibenzyl, Dimethyl terephthalate, 1,1-diphenylethanol, 1,1-diphenyl-2-propanol, 1,3-diphenoxy-2-propanol, p- (benzyloxy) benzyl alcohol, normal octadecylcarbamoyl-p-methoxycarbonylbenzene, Normal octadecylcarbamoylbenzene.
[0041]
In the present invention, various auxiliary agents may be added to improve the stability of the recorded image. Although the auxiliary agent is illustrated below, this invention is not limited to these.
[0042]
Zinc stearate, aluminum stearate, calcium stearate, zinc palmitate, zinc behenate, p-chlorobenzoic acid metal salt (Zn, Ca), p-nitrobenzoic acid metal salt (Zn, Ca), phthalic acid monobenzyl ester Metal salts (Zn, Ca), 4,4′-isopropylidene-bis (3-methyl-6-tert-butyl) phenol.
[0043]
As the binder used for the heat-sensitive recording material of the present invention, those conventionally known in the field of heat-sensitive recording can be used. The binder is exemplified below, but the present invention is not limited thereto.
[0044]
Completely saponified polyvinyl alcohol with a polymerization degree of 2000 or less, partially saponified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, amide-modified polyvinyl alcohol, sulfonic acid-modified polyvinyl alcohol, other modified polyvinyl alcohol, hydroxyethylcellulose, methylcellulose , Cellulose derivatives such as carboxymethyl cellulose and acetyl cellulose, casein, gelatin, styrene-maleic anhydride copolymer, styrene-butadiene copolymer, polymers and copolymers such as styrene, vinyl acetate, acrylamide, acrylate ester, Polyamide resin, silicon resin, petroleum resin, terpene resin, ketone resin, coumarone resin, etc. can be mentioned. These natural and synthetic polymer substances can be used by being dissolved in an organic solvent such as water or alcohol, or can be used in a state of being emulsified or pasty dispersed in a medium such as water. Two or more of these can also be used.
[0045]
Fillers used in the heat-sensitive recording material of the present invention include clay, calcined clay, diatomaceous earth, talc, kaolin, calcium carbonate, basic magnesium carbonate, barium sulfate, barium carbonate, aluminum hydroxide, zinc oxide, silica, hydroxide Examples include, but are not limited to, magnesium, titanium oxide, urea-formalin resin, polystyrene resin, phenolic resin, and other natural or synthetic inorganic or organic fillers. Two or more of these can be used.
[0046]
Examples of the additive include an ultraviolet absorber, an antifoaming agent, a fluorescent brightening agent, a water-resistant agent, a lubricant, and the like, but the present invention is not limited to these.
[0047]
The amount of the dye precursor and developer used in the heat-sensitive recording material of the present invention, and the types and amounts of other various components are determined according to the required performance and recording suitability, and are not particularly limited. 1 to 8 parts of developer and 1 to 20 parts of filler are preferable with respect to 1 part of the dye precursor, and the binder is preferably 10 to 25% in the total solid content.
[0048]
Examples of the support used in the heat-sensitive recording material of the present invention include fine paper, medium paper, coated paper, synthetic paper, plastic film, and the like, but the present invention is limited to these. It is not a thing.
[0049]
Further, for the purpose of enhancing the storage stability, an overcoat layer such as a polymer substance can be provided on the thermosensitive coloring layer. In addition, an undercoat layer containing an organic filler or an inorganic filler can be provided between the color forming layer and the support for the purpose of improving the storage stability and sensitivity.
[0050]
【Example】
The present invention will be specifically described below by way of examples illustrating the synthesis examples of the compounds of the present invention, the synthesis examples of starting materials suitable for the production thereof, and the production examples of thermosensitive recording materials using them as developers. To do. Further, the reactants and other components used are presented as representative examples, and various modifications can be made as described above within the scope of the present invention.
[0051]
-Synthesis of the compound of the present invention-
[Synthesis Example of Starting Material] Synthesis of 4-amino-N-phenylbenzenesulfonamide To 34.0 g of 4-acetamidobenzenesulfonyl chloride, 250 ml of methyl ethyl ketone, 300 ml of water and 18.6 g of sodium carbonate were added and dissolved. 13.6 g of aniline was added thereto and reacted at room temperature for 1 hour. Thereafter, 170 ml of 4N-aqueous sodium hydroxide solution was added, and the mixture was heated to reflux for 16 hours for reaction. The solvent was distilled off with an evaporator, the residue was acidified with 6N hydrochloric acid, and the resulting solid was collected by filtration. This was recrystallized from ethyl acetate to obtain 29.4 g (yield 81%) of 4-amino-N-phenylbenzenesulfonamide as a white solid.
<IR spectrum>
(KBr tablet method, cm ^-1 )
3420,3349,3294,3246,1638,1596,1495,1465,1435,1394,1319,1301,1220,1152,1093,1072,918,891,831,751,691,561
^<1 H-NMR spectrum>
_{(300MHz, DMSO-d 6,} δ / ppm, TMS)
5.92 (2H, s, NH ₂ ), 6.52 (2H, d, J = 9Hz, ArH), 6.96 (1H, t, J = 7Hz, ArH), 7.06 (2H, d, J = 8Hz, ArH), 7.18 (2H, t, J = 8Hz, ArH), 7.38 (2H, d, J = 8Hz, ArH), 9.82 (1H, s, NH)
< ^13C -NMR spectrum>
_{(75MHz, DMSO-d 6,} δ / ppm, TMS)
112.50,119.36,123.18,124.43,128.62,128.83,138.44,152.73
<MS spectrum>
(FAB-MS (M / Z))
249 (M + H) ⁺
[0052]
[Synthesis Example 1] Synthesis of 4,4′-bis (4-phenylsulfamoylphenylureido) diphenylmethane (A-01) 4.37 g of 4-amino-N-phenylbenzenesulfonamide was dissolved in 30 ml of THF. In a nitrogen atmosphere, a solution prepared by dissolving 2.0 g of MDI in 20 ml of THF was dropped, and the mixture was reacted by heating under reflux for 6 hours. After completion of the reaction, the solvent was distilled off with an evaporator, the residue was recrystallized with ethyl acetate, and a white solid of 4,4′-bis (4-phenylsulfamoylphenylureido) diphenylmethane (A-01) was obtained. 54 g (76% yield) was obtained.
<Disassembly point>
260-270 ° C
<IR spectrum>
(KBr tablet method, cm ^-1 )
3372,3190,1702,1594,1536,1512,1408,1313,1232,1152,1094,923,825,754,696,597,553
^<1 H-NMR spectrum>
_{(300MHz, DMSO-d 6,} δ / ppm, TMS)
_{3.82 (2H, s, CH 2} ), 6.98 (2H, t, J = 7Hz, ArH), 7.10 (8H, d, J = 7Hz, ArH), 7.19 (4H, t, J = 8Hz, ArH), 7.34 (4H, d, J = 8Hz, ArH), 7.55 (4H, d, J = 9Hz, ArH), 7.64 (4H, d, J = 9Hz, ArH), 8.68 (2H, s, NH), 9.00 (2H , s, NH), 10.07 (2H, s, SO ₂ NH)
< ^13C -NMR spectrum>
_{(75MHz, DMSO-d 6,} δ / ppm, TMS)
59.59,117.26,118.51,119.77,123.56,127.85,128.80,131.57,135.22,136.99,137.91,143.74,151.99,181.02
<MS spectrum>
(FAB-MS (M / Z))
747 (M + H) ⁺
[0053]
Synthesis Example 2 Synthesis of 2,4-bis (4-phenylsulfamoylphenylureido) toluene (A-13) 5.50 g of 4-amino-N-phenylbenzenesulfonamide was dissolved in 30 ml of THF. In a nitrogen atmosphere, a solution prepared by dissolving 1.75 g of 2,4-TDI in 20 ml of THF was dropped, and the reaction was performed by heating under reflux for 6 hours. After completion of the reaction, the solvent was distilled off with an evaporator, and the residue was recrystallized with ethyl acetate to obtain 2.82 g of a white solid of 2,4-bis (4-phenylsulfamoylphenylureido) toluene (A-13). (Yield 42%).
<Melting point>
218-220 ° C
<IR spectrum>
(KBr tablet method, cm ^-1 )
3352,1695,1596,1537,1499,1450,1410,1313,1220,1153,1094,923,828,753,697,616,595,556
^<1 H-NMR spectrum>
_{(300MHz, DMSO-d 6,} δ / ppm, TMS)
2.24 (3H, s, CH ₃ ), 6.94-7.24 (13H, m, ArH), 7.53-7.67 (8H, m, ArH), 8.45 (1H, s, NH), 8.81 (1H, s, NH), 9.01 (1H, s, NH), 9.46 (1H, s, NH)
< ^13C -NMR spectrum>
_{(75MHz, DMSO-d 6,} δ / ppm, TMS)
17.12,110.94.112.34.116.88.119.28,119.79.123.16.127.69.128.56,129.91,131.62,137.35,138.18,143.57,151.91,180.90
<MS spectrum>
(FAB-MS (M / Z))
671 (M + H) ⁺
[0054]
Synthesis Example 3 Synthesis of 1,6-bis (4-phenylsulfamoylphenylureido) hexane (A-25) 4.87 g of 4-amino-N-phenylbenzenesulfonamide was dissolved in 30 ml of THF. In a nitrogen atmosphere, a solution prepared by dissolving 1.50 g of HDI in 20 ml of THF was added dropwise and reacted by heating under reflux for 6 hours. After completion of the reaction, the solvent was distilled off with an evaporator, and the residue was recrystallized with ethyl acetate to obtain 3.67 g of a white solid of 1,6-bis (4-phenylsulfamoylphenylureido) hexane (A-25). (Yield 62%).
<Melting point>
237-239 ° C
<IR spectrum>
(KBr tablet method, cm ^-1 )
3382,3343,3140,2930,2860,2272,1685,1594,1543,1497,1405,1321,1242,1151,1095,925,833,755,701,593,552
^<1 H-NMR spectrum>
_{(300MHz, DMSO-d 6,} δ / ppm, TMS)
1.29-1.42 (8H, m, CH ₂ ), 3.07 (4H, q, J = 6Hz, NCH ₂ ), 6.25 (2H, t, J = 5Hz, CONH), 6.98 (2H, t, J = 7Hz, ArH ), 7.08 (4H, d, J = 8Hz, ArH), 7.19 (4H, t, J = 8Hz, ArH), 7.48 (4H, d, J = 9Hz, ArH), 7.58 (4H, d, J = 9Hz) , ArH), 8.80 (2H, s, ArNHCO), 10.03 (2H, s, NHSO ₂ )
< ^13C -NMR spectrum>
_{(75MHz, DMSO-d 6,} δ / ppm, TMS)
26.01,29.51,97.44,116.66,119.07,123.53,127.81,128.83,130.65,137.94,144.54,154.53,180.94
<MS spectrum>
(FAB-MS (M / Z))
671 (M + H) ⁺
[0055]
-Synthesis of compounds of comparative examples-
Synthesis Example 4 Synthesis of 4,4′-diphenylsulfamoyl-N, N′-diphenylurea (B-03) While cooling 25 ml of chlorosulfuric acid in an ice water bath, 10 g of N, N′-diphenylurea was cooled. Was gradually added. Thereafter, the reaction was allowed to stir at room temperature for 4 hours. The reaction solution was poured into ice to obtain 4,4′-dichlorosulfonyl-N, N′-diphenylurea as a white solid. To this, 100 ml of acetone and 100 ml of pyridine were added and dissolved, and 8.77 g of aniline was added dropwise while cooling in an ice water bath. Thereafter, the reaction was carried out by stirring at 30 ° C. for 2 hours. Acetone in the reaction solution was distilled off with an evaporator, and the residue was acidified with dilute hydrochloric acid. The residue obtained by extracting this with ethyl acetate and evaporating the solvent was recrystallized with acetone + ethyl acetate, and a white solid of 4,4′-diphenylsulfamoyl-N, N′-diphenylurea (B-03) 5 Obtained .41 g (22% yield).
<Disassembly point>
283 ° C
<IR spectrum>
(KBr tablet method, cm ^-1 )
3376,3305,3268,3189,1716,1594,1553,1541,1495,1407,1342,1322,1243,1215,1149,1095,933,913,900,830,757,697,664,563,543
^<1 H-NMR spectrum>
_{(300MHz, DMSO-d 6,} δ / ppm, TMS)
7.00 (2H, t, J = 7Hz, ArH), 7.10 (4H, d, J = 8Hz, ArH), 7.22 (4H, t, J = 7Hz, ArH), 7.58 (4H, t, J = 9Hz, ArH ), 7.71 (4H, d, J = 9Hz, ArH), 9.23 (2H, s, NHCONH), 10.16 (1H, s, NHSO 2)
< ^13C -NMR spectrum>
_{(75MHz, DMSO-d 6,} δ / ppm, TMS)
117.9,119.9,123.8,128.0,129.1,132.2,137.9,143.3,151.8
<MS spectrum>
(FAB-MS (M / Z))
523 (M + H) ⁺
[0056]
-Manufacture of thermal recording material-
[Examples 1 to 3]
A heat-sensitive recording material comprising the following composition was produced. That is, first, the dye dispersion liquid (liquid A) and the developer dispersion liquid (liquid B) having the following composition were each ground to an average particle diameter of 1 μm with a sand grinder.

Next, A liquid, B liquid and kaolin clay dispersion were mixed at the following ratio to obtain a heat-sensitive paint.
Liquid A: Dye dispersion 9.2 parts Liquid B: Developer dispersion 36.0 parts Kaolin clay (50% dispersion) 12.0 parts Amount of this thermal coating applied on one side of 50 g / m ² base paper It was applied and dried so as to be 6.0-6.5 g / m ² , and this sheet was processed with a super calender so that the smoothness became 500-600 seconds to produce a heat-sensitive recording material.
[0057]
[Comparative Examples 1-3]
A heat-sensitive recording material was produced in the same manner as in Examples 1 to 3 except that the developer shown below was used instead of the compound of the present invention in the developer dispersion (liquid B).
4-Hydroxy-4′-isopropoxydiphenylsulfone (B-01)
N, N′-diphenylurea (B-02)
4,4′-Diphenylsulfamoyl-N, N′-diphenylurea (B-03)
[0058]
-Evaluation of thermal recording material-
[Coloring method]
Using the UBI printer 201 (manufactured by UBI), the produced thermosensitive recording medium was recorded at an applied energy of 450 mj / mm ² . Subsequently, the image density of the recording part and the white paper part was measured with a Macbeth densitometer (RD-914, using an amber filter). Using this as a test sample, the following tests were conducted.
[Plasticizer resistance test]: A test sample was brought into contact with a vinyl chloride film (Dialap 300G manufactured by Mitsubishi Resin Co., Ltd.), allowed to stand at 40 ° C. for 24 hours, and the residual image density of the recorded portion was measured with a Macbeth densitometer. .
[Oil resistance test]: The test sample was immersed in salad oil for 1 hour, wiped off the oil, and allowed to stand at room temperature for 24 hours, and the residual image density of the recorded portion was measured with a Macbeth densitometer.
[Water resistance test]: The test sample was immersed in tap water for 24 hours, dried at 30 ° C. for 2 hours, and the residual image density of the recorded portion was measured with a Macbeth densitometer.
[Heat resistant ground color test of blank paper portion]: The test sample was allowed to stand at 100 ° C. for 30 minutes, and the density of the blank paper portion was measured with a Macbeth densitometer.
Table 1 shows the results of the image storage stability test of the image recording portion, and Table 2 shows the results of the heat resistant ground color test of the blank paper portion. In Table 1, the larger the value, the better the image storage stability, and in Table 2, the smaller the value, the better the heat resistant ground color stability.
[0059]
[Table 1]
Table 1. Results of image preservation test

[Table 2]
Table 2. Results of heat resistant ground color test

[0060]
As is clear from the results in Tables 1 and 2, Examples 1 to 3 using the compound of the present invention as the developer are those of Comparative Example 1 and the phenylsulfamoyl group using the conventional phenol developer. Compared to Comparative Example 2 of a urea developer not having a urea developer, and Comparative Example 3 of a urea developer having two phenylsulfamoyl groups but only one urea structure, the oil resistance and resistance Not only the plasticizer property is remarkably improved but also the water resistance is good, and the heat resistant ground color stability of the white paper portion is also excellent.
[0061]
【The invention's effect】
The compounds of the present invention have sufficient ability to develop a dye precursor. In addition, a heat-sensitive recording material using the compound as a developer is extremely useful because it is very excellent in image storability of the recording portion and heat-resistant ground color stability of the blank paper portion.

Claims (4)

In a heat-sensitive recording material having a heat-sensitive color-developing layer containing a colorless or light-colored dye precursor and a color developer that reacts upon heating to develop the dye precursor, a phenylsulfamoyl group (PhNHSO ₂ ) is used as the color developer. -) and the heat-sensitive recording material characterized by containing a compound represented by the following general formula each two chromatic in one molecule of urea structure (1).

(However, R ¹ and R ² each represent an alkyl group, an alkoxy group, and an electron-withdrawing group. M represents an integer of 0 to 5. n represents an integer of 0 to 4. A represents a divalent group. To express.) The heat-sensitive recording material according to claim 1, wherein the developer is characterized in that a compound represented by the following general formula (2).

^(Wherein, R 3, ^{R 4} are each an alkyl group, an alkoxy group, an integer of .o 0-5 representing an electron-withdrawing group .p is an integer of 0-4.) The heat-sensitive recording material according to claim 1, wherein the developer is characterized in that a compound represented by the following general formula (3).

^{(Wherein, R 5, R 6, R} 7 are each an alkyl group, an alkoxy group, .r represents an integer of .q 0-5 representing an electron withdrawing group, s represents an integer of 0 to 4.) The heat-sensitive recording material according to claim 1, wherein the developer is characterized in that a compound represented by the following general formula (4).

^(Wherein, R 8, ^{R 9} are each an alkyl group, an alkoxy group, .v .t representing an electron-withdrawing group is .u represents an integer of 0 to 5 represents an integer of 0 to 4 integer from 2 to 12 Represents.)