JP2004338273A - Thermal recording material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal recording material which enables a stable image formation without being affected by fluctuation in the humidity of an using environment. <P>SOLUTION: This thermal recording material, which includes a component A, a component B for making the component A develop a color, and an isolating layer for isolating the components A and B from each other, makes the component B, passing through the isolating layer, react with the component A, so as to form a dye component; the isolating layer is constituted as a multilayer structure of at least two layers which is composed of polymer components different from each other; and a 0%RH/90%RH moisture permeability of the polymer component constituting a layer, which is not brought into contact with the component A of the isolating layer, is set at 20 g/m<SP>2</SP>24 hrmm or less. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００６０】
【化２】

【００６１】
前記重合開始剤の含有量としては、本発明におけるモノマー１質量部に対して、０．００１〜０．１質量部が好ましく、０．０１〜０．０５質量部がさらに好ましい。さらに、重合性界面活性剤としてカチオン性若しくはアニオン性の重合性界面活性剤を用いることもでき、この場合には該重合性界面活性剤と反対電荷を有する水溶性の重合開始剤を用いるのが好ましい。
【００６２】
また、上記の修飾工程において液組成物に本発明におけるモノマーを添加するタイミングとしては、上記カプセル壁形成工程におけるカプセル壁の形成後であれば特に限定はなく、例えば、カプセル内壁形成後（乳化重合後）連続してモノマーを添加してもよい。また、第２のポリマー成分は単独種および２種以上のいずれであってもよく、所望の性能に応じて適宜決定することができる。また、必要に応じて、本発明におけるモノマーの重合反応途中に、該本発明におけるモノマーとは異なる種類の本発明におけるモノマーをさらに添加し、異なる２種の第２のポリマー成分でヘテロ型にカプセル壁を修飾してもよい。
【００６３】
次に、感熱記録材料の発色成分として含有する成分Ａおよび成分Ｂとしては、下記組合せの成分が挙げられる。以下の各組合せにおいて、前者は成分Ａを後者は成分Ｂを示す。
（ア）電子供与性染料前駆体と電子受容性化合物との組合せ。
（イ）ジアゾニウム塩化合物とカップリング成分（以下、適宜「カプラー化合物」と称する。）との組合せ。
（ウ）ベヘン酸銀、ステアリン酸銀等の有機酸金属塩と、プロトカテキン酸、スピロインダン、ハイドロキノン等の還元剤との組合せ。
（エ）ステアリン酸第二鉄、ミリスチン酸第二鉄等の長鎖脂肪酸鉄塩と、タンニン酸、没食子酸、サリチル酸アンモニウム等のフェノール類との組合せ。
（オ）酢酸、ステアリン酸、パルミチン酸等のニッケル、コバルト、鉛、銅、鉄、水銀、銀塩のような有機酸重金属塩と、硫化カルシウム、硫化ストロンチウム、硫化カリウム等のアルカリ金属又はアルカリ土類金属硫化物との組合せ、又は前記有機酸重金属塩と、ｓ−ジフェニルカルバジド、ジフェニルカルバゾン等の有機キレート剤との組合せ。
【００６４】
（カ）銀、鉛、水銀、ナトリウム等の硫酸塩等の重金属硫酸塩と、ナトリウムテトラチオネート、チオ硫酸ソーダ、チオ尿素等の硫黄化合物との組合せ。
（キ）ステアリン酸第二鉄等の脂肪族第二鉄塩と、３，４−ヒドロキシテトラフェニルメタン等の芳香族ポリヒドロキシ化合物との組合せ。
（ク）シュウ酸銀、シュウ酸水銀等の有機酸金属塩と、ポリヒドロキシアルコール、グリセリン、グリコール等の有機ポリヒドロキシ化合物との組合せ。
（ケ）ペラルゴン酸第二鉄、ラウリン酸第二鉄等の脂肪酸第二鉄塩と、チオセシルカルバミドやイソチオセシルカルバミド誘導体との組合せ。
（コ）カプロン酸鉛、ペラルゴン酸鉛、ベヘン酸鉛等の有機酸鉛塩と、エチレンチオ尿素、Ｎ−ドデシルチオ尿素等のチオ尿素誘導体との組合せ。
【００６５】
（サ）ステアリン酸第二鉄、ステアリン酸銅等の高級脂肪族重金属塩とジアルキルジチオカルバミン酸亜鉛との組合せ。
（シ）レゾルシンとニトロソ化合物との組合せのようなオキサジン染料を形成するもの。
（ス）ホルマザン化合物と還元剤及び／又は金属塩との組合せ。
（セ）保護された色素（又はロイコ色素）プレカーサと脱保護剤との組合せ。
（ソ）酸化型発色剤と酸化剤との組合せ。
（タ）フタロニトリル類とジイミノイソインドリン類との組合せ。（フタロシアニンが生成する組合せ。）
（チ）イソシアナート類とジイミノイソインドリン類との組合せ（着色顔料が生成する組合せ）。
（ツ）顔料プレカーサーと酸又は塩基との組合せ（顔料が形成する組合せ）。
【００６６】
上記の中でも、実質的に無色の電子供与性染料前駆体（以下、電子供与性無色染料という）と電子受容性化合物との組合せ、またはジアゾニウム塩化合物とカプラー化合物との組合せが好ましい。特に、成分Ａとして電子供与性無色染料またはジアゾニウム塩化合物を好適に用いることができる。
【００６７】
前記電子供与性無色染料としては、従来より公知のものを使用することができ、その具体例として下記化合物を挙げることができる。ただし、本発明においてはこれらに限定されるものではない。具体的には、フタリド系化合物、フルオラン系化合物、フェノチアジン系化合物、インドリルフタリド系化合物、ロイコオーラミン系化合物、ローダミンラクタム系化合物、トリフェニルメタン系化合物、トリアゼン系化合物、スピロピラン系化合物、ピリジン系、ピラジン系化合物、フルオレン系化合物等の各種化合物を挙げることができる。
【００６８】
フタリド系化合物としては、例えば、米国再発行特許第２３，０２４号、米国特許第３，４９１，１１１号、同第３，４９１，１１２号、同第３，４９１，１１６号及び同第３，５０９，１７４号に記載の化合物が挙げられ、具体的には、３，３−ビス（ｐ−ジメチルアミノフェニル）−６−ジメチルアミノフタリド、３，３−ビス（ｐ−ジエチルアミノ−ｏ−ブトキシフェニル）−４−アザフタリド、３−（ｐ−ジエチルアミノ−ｏ−ブトキシフェニル）−３−（１−ペンチル−２−メチルインドール−３−イル）−４−アザフタリド、３−（ｐ−ジプロピルアミノ−ｏ−メチルフェニル）−３−（１−オクチル−２−メチルインドール−３−イル）−５−アザ（又は−６−アザ、又は−７−アザ）フタリド等が挙げられる。
【００６９】
フルオラン系化合物としては、例えば、米国特許第３，６２４，１０７号、同第３，６２７，７８７号、同第３，６４１，０１１号、同第３，４６２，８２８号、同第３，６８１，３９０号、同第３，９２０，５１０号、同第３９５９，５７１号に記載の化合物が挙げられ、具体的には、２−（ジベンジルアミノ）フルオラン、２−アニリノ−３−メチル−６−ジエチルアミノフルオラン、２−アニリノ−３−メチル−６−ジブチルアミノフルオラン、２−アニリノ−３−メチル−６−Ｎ−エチル−Ｎ−イソアミルアミノフルオラン、２−アニリノ−３−メチル−６−Ｎ−メチル−Ｎ−シクロヘキシルアミノフルオラン、２−アニリノ−３−クロル−６−ジエチルアミノフルオラン、２−アニリノ−３−メチル−６−Ｎ−エチル−Ｎ−イソブチルアミノフルオラン、２−アニリノ−６−ジブチルアミノフルオラン、２−アニリノ−３−メチル−６−Ｎ−エチル−Ｎ−テトラヒドロフルフリルアミノフルオラン、２−アニリノ−３−メチル−６−ピペリジノアミノフルオラン、２−（ｏ−クロロアニリノ）−６−ジエチルアミノフルオラン、２−（３，４−ジクロルアニリノ）−６−ジエチルアミノフルオラン等が挙げられる。
【００７０】
フェノチアジン系化合物としては、例えば、ベンゾイルロイコンメチレンブルー、ｐ−ニトロベンジルロイコメチレンブルー等が挙げられ、ロイコオーラミン系化合物としては、例えば、４，４’−ビス−ジメチルアミノベンズヒドリンベンジルエーテル、Ｎ−ハロフェニル−ロイコオーラミン、Ｎ−２，４，５−トリクロロフェニルロイコオーラミン等が挙げられ、ローダミンラクタム系化合物としては、ローダミン−Ｂ−アニリノラクタム、ローダミン−（ｐ−ニトリノ）ラクタム等が挙げられる。また、スピロピラン系化合物としては、例えば、米国特許第３，９７１，８０８号に記載の化合物が挙げられ、具体的には、３−メチル−スピロ−ジナフトピラン、３−エチル−スピロ−ジナフトピラン３，３’−ジクロロ−スピロ−ジナフトピラン、３−ベンジルスピロ−ジナフトピラン、３−メチル−ナフト−（３−メトキシ−ベンゾ）スピロピラン、３−プロピル−スピロ−ジベンゾピラン等が挙げられ、ピリジン系、ピラジン系化合物類としては、例えば、米国特許第３，７７５，４２４号、同第３，８５３，８６９号、同第４，２４６，３１８号に記載の化合物が挙げられ、フルオレン系化合物としては、例えば、特願昭６１−２４０９８９号等に記載の化合物が挙げられる。
【００７１】
カラー感熱記録材料とする場合には、シアン、マゼンタ、イエローから選ばれる１つ以上の発色色素用の電子供与性無色染料が用いられる。シアン、マゼンタ、イエロー発色としては、米国特許第４，８００，１４９号等に記載のものを使用でき、さらにイエロー発色色素用電子供与性無色染料としては、米国特許第４，８００，１４８号等に記載のものも使用でき、シアン発色色素用電子供与性無色染料としては、特開平６３−５３５４２号等に記載のものも使用できる。
【００７２】
前記電子供与性無色染料の含有量は、記録層中に０．０１〜３ｇ／ｍ^２が好ましく、０．１〜１ｇ／ｍ^２がより好ましい。前記含有量を上記範囲にすると、特に十分な発色濃度を得ることができると共に、塗布適性が劣化することもない。多層構成の場合には、上記範囲で電子供与性無色染料を含有する記録層を複数積層して構成する。
【００７３】
前記ジアゾニウム塩化合物としては、Ａｒ−Ｎ_２ ^＋・Ｘ⁻〔Ａｒは芳香族環基を表し、Ｘ⁻は酸アニオンを表す。〕で表される化合物が挙げられる。このジアゾニウム塩化合物は加熱によりカプラーとカップリング反応を起こして発色したり、また光によって分解する化合物である。これらはＡｒ部分の置換基の位置や種類によって、その最大吸収波長を制御することが可能である。
【００７４】
前記式中のＡｒは、置換又は無置換のアリール基を表す。置換基としては、アルキル基、アルコキシ基、アルキルチオ基、アリール基、アリールオキシ基、アリールチオ基、アシル基、アルコキシカルボニル基、カルバモイル基、カルボアミド基、スルホニル基、スルファモイル基、スルホンアミド基、ウレイド基、ハロゲン基、アミノ基、ヘテロ環基、ニトロ基、シアノ基等が挙げられ、これら置換基は、更に置換されていてもよい。
【００７５】
前記アリール基としては、炭素原子数６〜３０のアリール基が好ましく、例えば、フェニル基、２−メチルフェニル基、２−クロロフェニル基、２−メトキシフェニル基、２−ブトキシフェニル基、２−（２−エチルヘキシルオキシ）フェニル基、２−オクチルオキシフェニル基、３−（２，４−ジ−ｔ−ペンチルフェノキシエトキシ）フェニル基、４−クロロフェニル基、２，５−ジクロロフェニル基、２，４，６−トリメチルフェニル基、３−クロロフェニル基、３−メチルフェニル基、３−メトキシフェニル基、３−ブトキシフェニル基、３−シアノフェニル基、３−（２−エチルヘキシルオキシ）フェニル基、３，４−ジクロロフェニル基、３，５−ジクロロフェニル基、３，４−ジメトキシフェニル基、３−（ジブチルアミノカルボニルメトキシ）フェニル基、４−シアノフェニル基、４−メチルフェニル基、４−メトキシフェニル基、４−ブトキシフェニル基、４−（２−エチルヘキシルオキシ）フェニル基、４−ベンジルフェニル基、４−アミノスルホニルフェニル基、４−Ｎ，Ｎ−ジブチルアミノスルホニルフェニル基、４−エトキシカルボニルフェニル基、４−（２−エチルヘキシルカルボニル）フェニル基、４−フルオロフェニル基、３−アセチルフェニル基、２−アセチルアミノフェニル基、４−（４−クロロフェニルチオ）フェニル基、４−（４−メチルフェニル）チオ−２，５−ブトキシフェニル基、４−（Ｎ−ベンジル−Ｎ−メチルアミノ）−２−ドデシルオキシカルボニルフェニル基、等が挙げられる。
また、これらの基は、さらに、アルキルオキシ基、アルキルチオ基、置換フェニル基、シアノ基、置換アミノ基、ハロゲン原子、ヘテロ環基等により置換されていてもよい。
【００７６】
前記ジアゾニウム塩化合物の含有量は、記録層中に０．０１〜３ｇ／ｍ^２が好ましく、０．０２〜１．０ｇ／ｍ^２がより好ましい。前記含有量を上記範囲にすると、特に十分な発色性が得られると共に、感度が低下したり、定着時間を長くする必要が生じることもない。
【００７７】
次に、前記電子供与性無色染料と反応して発色させる電子受容性化合物、前記ジアゾニウム塩化合物と反応して発色させるカプラー化合物について詳述する。
前記電子受容性化合物としては、特開平４−２２６４５５号に記載の３−ハロ−４−ヒドロキシ安息香酸、特開昭６３−１７３６８２号に記載のヒドロキシ基を有する安息香酸のメタアクリロキシエチルエステル、アクリロキシエチルエステル、同５９−８３６９３号、同６０−１４１５８７号、同６２−９９１９０号に記載のヒドロキシ基を有する安息香酸とヒドロキシメチルスチレンとのエステル、欧州特許２９３２３号に記載のヒドロキシスチレン、特開昭６２−１６７０７７号、同６２−１６７０８号に記載のハロゲン化亜鉛のＮ−ビニルイミダゾール錯体、同６３−３１７５５８号に記載の電子受容性化合物等を参考にして合成できる化合物等が挙げられる。中でも、３−ハロ−４−ヒドロキシ安息香酸が好ましい。
【００７８】
前記３−ハロ−４−ヒドロキシ安息香酸には、例えば、３−クロロ−４−ヒドロキシ安息香酸エステルビニルフェネチルエステル、３−クロロ−４−ヒドロキシ安息香酸ビニルフェニルプロピルエステル、３−クロロ−４−ヒドロキシ安息香酸−（２−アクリロイルオキシエチル）エステル、３−クロロ−４−ヒドロキシ安息香酸−（２−メタクリロイルオキシエチル）エステル、３−クロロ−４−ヒドロキシ安息香酸−（２−アクリロイルオキシプロピル）エステル、３−クロロ−４−ヒドロキシ安息香酸−（２−メタクリロイルオキシプロピル）エステル、３−クロロ−４−ヒドロキシ安息香酸−（３−アクリロイルオキシプロピル）エステル、３−クロロ−４−ヒドロキシ安息香酸−（３−メタクリロイルオキシプロピル）エステル、３−クロロ−４−ヒドロキシ安息香酸−（４−アクリロイルオキシブチル）エステル、３−クロロ−４−ヒドロキシ安息香酸−（４−メタクリロイルオキシブチル）エステル、３−クロロ−４−ヒドロキシ安息香酸−（５−アクリロイルオキシペンチル）エステル、３−クロロ−４−ヒドロキシ安息香酸−（５−メタクリロイルオキシペンチル）エステル、３−クロロ−４−ヒドロキシ安息香酸−（６−アクリロイルオキシヘキシル）エステル、３−クロロ−４−ヒドロキシ安息香酸−（６−メタクリロイルオキシヘキシル）エステル、３−クロロ−４−ヒドロキシ安息香酸−（８−アクリロイルオキシオクチル）エステル、３−クロロ−４−ヒドロキシ安息香酸−（８−メタクリロイルオキシオクチル）エステル等、
【００７９】
スチレンスルホニルアミノサリチル酸、ビニルベンジルオキシフタル酸、β−メタクリロキシエトキシサリチル酸亜鉛、β−アクリロキシエトキシサリチル酸亜鉛、ビニロキシエチルオキシ安息香酸、β−メタクリロキシエチルオルセリネート、β−アクリロキシエチルオルセリネート、β−メタクリロキシエトキシフェノール、β−アクリロキシエトキシフェノール、β−メタクリロキシエチル−β−レゾルシネート、β−アクリロキシエチル−β−レゾルシネート、ヒドロキシスチレンスルホン酸−Ｎ−エチルアミド、β−メタクリロキシプロピル−ｐ−ヒドロキシベンゾエート、β−アクリロキシプロピル−ｐ−ヒドロキシベンゾエート、メタクリロキシメチルフェノール、アクリロキシメチルフェノール、メタクリルアミドプロパンスルホン酸、アクリルアミドプロパンスルホン酸、β−メタクリロキシエトキシ−ジヒドロキシベンゼン、β−アクリロキシエトキシ−ジヒドロキシベンゼン、γ−スチレンスルホニルオキシ−β−メタクリロキシプロパンカルボン酸、
【００８０】
γ−アクリロキシプロピル−α−ヒドロキシエチルオキシサリチル酸、β−ヒドロキシエトキニルフェノール、β−メタクリロキシエチル−ｐ−ヒドロキシシンナメート、β−アクリロキシエチル−ｐ−ヒドロキシシンナメート、３，５ジスチレンスルホン酸アミドフェノール、メタクリロキシエトキシフタル酸、アクリロキシエトキシフタル酸、メタクリル酸、アクリル酸、メタクリロキシエトキシヒドロキシナフトエ酸、アクリロキシエトキシヒドロキシナフトエ酸、３−β−ヒドロキシエトキシフェノール、β−メタクリロキシエチル−ｐ−ヒドロキシベンゾエート、β−アクリロキシエチル−ｐ−ヒドロキシベンゾエート、β’−メタクリロキシエチル−β−レゾルシネート、β−メタクリロキシエチルオキシカルボニルヒドロキシ安息香酸、β−アクリロキシエチルオキシカルボニルヒドロキシ安息香酸、Ｎ，Ｎ’−ジ−β−メタクリロキシエチルアミノサリチル酸、Ｎ，Ｎ’−ジ−β−アクリロキシエチルアミノサリチル酸、Ｎ，Ｎ’−ジ−β−メタクリロキシエチルアミノスルホニルサリチル酸、Ｎ，Ｎ’−ジ−β−アクリロキシエチルアミノスルホニルサリチル酸、及びこれらの金属塩（例えば、亜鉛塩等）、等が好適に挙げられる。
【００８１】
上記のほか、例えば、フェノール誘導体、サリチル酸誘導体、芳香族カルボン酸の金属塩、酸性白土、ペントナイト、ノボラック樹脂、金属処理ノボラック樹脂、金属錯体等も挙げることができる。具体的には、特公昭４０−９３０９号、特公昭４５−１４０３９号、特開昭５２−１４０４８３号、特開昭４８−５１５１０号、特開昭５７−２１０８８６号、特開昭５８−８７０８９号、特開昭５９−１１２８６号、特開昭６０−１７６７９５号、特開昭６１−９５９８８号等に記載されている。具体的には、下記化合物を挙げることができる。
【００８２】
フェノール誘導体としては、例えば、２，２’−ビス（４−ヒドロキシフェニル）プロパン、４−ｔ−ブチルフェノール、４−フェニルフェノール、４−ヒドロキシジフェノキシド、１，１’−ビス（３−クロロ−４−ヒドロキシフェニル）シクロヘキサン、１，１’−ビス（４−ヒドロキシフェニル）シクロヘキサン、１，１’−ビス（３−クロロ−４−ヒドロキシフェニル）−２−エチルブタン、４，４’−ｓｅｃ−イソオクチリデンジフェノール、４，４’−ｓｅｃ−ブチリデンジフェノール、４−ｔｅｒｔ−オクチルフェノール、４−ｐ−メチルフェニルフェノール、４，４’−メチルシクロヘキシリデンフェノール、４，４’−イソペンチリデンフェノール、ｐ−ヒドロキシ安息香酸ベンジル等が挙げられる。
【００８３】
サリチル酸誘導体としては、例えば、４−ペンタデシルサリチル酸、３，５−ジ（α−メチルベンジル）サリチル酸、３，５−ジ（ｔｅｒｔ−オクチル）サリチル酸、５−オクタデシルサリチル酸、５−α−（ｐ−α−メチルベンジルフェニル）エチルサリチル酸、３−α−メチルベンジル−５−ｔｅｒｔ−オクチルサリチル酸、５−テトラデシルサリチル酸、４−ヘキシルオキシサリチル酸、４−シクロヘキシルオキシサリチル酸、４−デシルオキシサリチル酸、４−ドデシルオキシサリチル酸、４−ペンタデシルオキシサリチル酸、４−オクタデシルオキシサリチル酸等、及びこれらの亜鉛、アルミニウム、カルシウム、銅、鉛塩等が挙げられる。
【００８４】
前記電子受容性化合物の含有量としては、電子供与性無色染料１質量部に対して、０．５〜２０質量部が好ましく、３〜１０質量部がより好ましい。電子供与性無色染料の含有量を上記範囲にすると、特に十分な発色濃度を得ることができると共に、感度の低下や塗布適性の劣化を招くこともない。
【００８５】
前記カプラー化合物は、塩基性雰囲気及び／又は中性雰囲気で上記のジアゾニウム塩化合物とカップリングして色素を形成するものであり、色相調整等種々の目的に応じて、複数種を併用して用いることができる。該カプラー化合物としては、例えば、レゾルシン、フロログルシン、２，３−ジヒドロキシナフタレン、２，３−ジヒドロキシナフタレン−６−スルホン酸ナトリウム、１−ヒドロキシ−２−ナフトエ酸モルホリノプロピルアミド、２−ヒドロキシ−３−ナフタレンスルホン酸ナトリウム、２−ヒドロキシ−３−ナフタレンスルホン酸アニリド、２−ヒドロキシ−３−ナフタレンスルホン酸モルホリノプロピルアミド、２−ヒドロキシ−３−ナフタレンスルホン酸−２−エチルヘキシルオキシプロピルアミド、２−ヒドロキシ−３−ナフタレンスルホン酸−２−エチルヘキシルアミド、５−アセトアミド−１−ナフトール、１−ヒドロキシ−８−アセトアミドナフタレン−３，６−ジスルホン酸ナトリウム、１−ヒドロキシ−８−アセトアミドナフタレン−３，６−ジスルホン酸ジアニリド、１，５−ジヒドロキシナフタレン、２−ヒドロキシ−３−ナフトエ酸モルホリノプロピルアミド、２−ヒドロキシ−３−ナフトエ酸オクチルアミド、２−ヒドロキシ−３−ナフトエ酸アニリド、
【００８６】
５，５−ジメチル−１，３−シクロヘキサンジオン、１，３−シクロペンタンジオン、５−（２−ｎ−テトラデシルオキシフェニル）−１，３−シクロヘキサンジオン、５−フェニル−４−メトキシカルボニル−１，３−シクロヘキサンジオン、５−（２，５−ジ−ｎ−オクチルオキシフェニル）−１，３−シクロヘキサンジオン、Ｎ，Ｎ’−ジシクロヘキシルバルビツール酸、Ｎ，Ｎ’−ジ−ｎ−ドデシルバルビツール酸、Ｎ−ｎ−オクチル−Ｎ’−ｎ−オクタデシルバルビツール酸、Ｎ−フェニル−Ｎ’−（２，５−ジ−ｎ−オクチルオキシフェニル）バルビツール酸、Ｎ，Ｎ’−ビス（オクタデシルオキシカルボニルメチル）バルビツール酸、１−フェニル−３−メチル−５−ピラゾロン、１−（２，４，６−トリクロロフェニル）−３−アニリノ−５−ピラゾロン、１−（２，４，６−トリクロロフェニル）−３−ベンズアミド−５−ピラゾロン、６−ヒドロキシ−４−メチル−３−シアノ−１−（２−エチルヘキシル）−２−ピリドン、２，４−ビス−（ベンゾイルアセトアミド）トルエン、１，３−ビス−（ピバロイルアセトアミドメチル）ベンゼン、ベンゾイルアセトニトリル、テノイルアセトニトリル、アセトアセトアニリド、ベンゾイルアセトアニリド、ピバロイルアセトアニリド、２−クロロ−５−（Ｎ−ｎ−ブチルスルファモイル）−１−ピバロイルアセトアミドベンゼン、１−（２−エチルヘキシルオキシプロピル）−３−シアノ−４−メチル−６−ヒドロキシ−１，２−ジヒドロピリジン−２−オン、１−（ドデシルオキシプロピル）−３−アセチル−４−メチル−６−ヒドロキシ−１，２−ジヒドロピリジン−２−オン、１−（４−ｎ−オクチルオキシフェニル）−３−ｔｅｒｔ−ブチル−５−アミノピラゾール等が挙げられる。
【００８７】
カプラー化合物の詳細については、特開平４−２０１４８３号、特開平７−２２３３６７号、特開平７−２２３３６８号、特開平７−３２３６６０号、特開平５−２７８６０８号、特開平５−２９７０２４号、特開平６−１８６６９号、特開平６−１８６７０号、特開平７−３１６２８０号等の公報に記載されている。本出願人が、先に提出した特願平８−０２７０９５号、特願平８−０２７０９６号、特願平８−０３０７９９号、特願平８−１２６１０号、特願平８−１３２３９４号、特願平８−３５８７５５号、特願平８−３５８７５６号、特願平９−０６９９９０号等に記載ししたものも参照できる。
【００８８】
前記カプラー化合物の含有量としては、ジアゾニウム塩化合物１質量部に対して、０．５〜２０質量部が好ましく、１〜１０質量部がより好ましい。カプラー化合物の含有量を上記範囲にすると、発色性の点でより効果的であり、塗布適性が劣化することもない。
【００８９】
前記カプラー化合物は、その他の成分と共に水溶性高分子を添加して、サンドミル等により固体分散して用いることもできるが、適当な乳化助剤とともに乳化し、乳化物として用いることもできる。固体分散又は乳化する方法としては、特に限定はなく、公知の方法の中から適宜選択することができる。方法の詳細については、特開昭５９−１９０８８６号、特開平２−１４１２７９号、特開平７−１７１４５号の各公報に記載されている。
【００９０】
また、カップリング反応を促進する目的で、第３級アミン類、ピペリジン類、ピペラジン類、アミジン類、フォルムアミジン類、ピリジン類、グアニジン類、モルホリン類等の有機塩基を用いることが好ましい。有機塩基については、特開昭５７−１２３０８６号、特開昭６０−４９９９１号、特開昭６０−９４３８１号、特願平７−２２８７３１号、特願平７−２３５１５７号、特願平７−２３５１５８号等の各公報に記載されている。有機塩基の使用量は特に限定されるものではないが、ジアゾニウム塩化合物１モルに対し、１〜３０モルが好ましい。
【００９１】
【実施例】
以下、実施例により本発明を具体的に説明するが、本発明はこれらの実施例に限定されるものではない。なお、実施例中の「％」は特に断らない限り質量基準である。
【００９２】
（実施例１）
−サンプルの調製−
厚さ１３０μｍのトリアセチルセルロース支持体の上に、下記化合物（１）［成分Ａ］の酢酸エチル溶液を乾燥後の層厚が約３μｍとなるようにスピンコートし乾燥させた後、さらにその上層（第１隔離層）としてナイロン６６のジメチルスルホキシド（ＤＭＳＯ）溶液を乾燥後の層厚が約１０〜１５μｍとなるように塗布し、乾燥させた。その後、第１隔離層の上層として更に塩化ビニリデン（０％ＲＨ／９０％ＲＨにおける透湿度０．１〜０．３ｇ／ｍ^２・２４ｈｒ・ｍｍ〔２５℃〕；重量法）のジメチルホルムアミド（ＤＭＦ）溶液を乾燥後の層厚が約１０〜１５μｍとなるようにスピンコートし、乾燥させて第２隔離層を形成した。また更に、第２隔離層の上に別途調製した、ポリビニルアルコールをバインダーとする下記化合物（２）［成分Ｂ］の乳化物（固形分濃度３０％、化合物（２）の該固形分に対する濃度は５０％）を、乾燥後の層厚が３μｍとなるように塗布し、乾燥させた。以上のようにして、支持体／成分Ａ含有層／第１隔離層／第２隔離層／成分Ｂ含有層で構成されたサンプル１を得た。本サンプル１の隔離層は第１隔離層および第２隔離層の二層構造に構成されている。
【００９３】
【化３】

【００９４】
−評価−
上記より得たサンプル１を２３℃／２０％ＲＨ、および２３℃／８０％ＲＨの環境条件のもとにそれぞれ個別に一晩放置した後、各々について成分Ｂ含有層の表面から静発色試験器により１０秒間加熱したところ、印加温度に相当する濃度のシアン色が得られた。このシアン色の部分の濃度をＸ−ｒｉｔｅ（Ｘ−ｒｉｔｅ社製）を用いて測定し、最大濃度の５０％に相当する濃度が得られる各温度の差（８０％における温度−２０％における温度）を算出した。算出した結果を下記表１に示す。
【００９５】
（比較例１）
実施例１において、塩化ビニリデンのテトラヒドロフラン（ＴＨＦ）溶液を塗布せず第２隔離層を設けなかったこと以外、実施例１と同様にして、支持体／成分Ａ含有層／第１隔離層／成分Ｂ含有層に構成されたサンプル２を得ると共に、同様の評価を行なった。
【００９６】
（比較例２）
実施例１において、塩化ビニリデンのテトラヒドロフラン（ＴＨＦ）溶液を、ポリビニルアルコール（０％ＲＨ／９０％ＲＨにおける透湿度３６６ｇ／ｍ^２・２４ｈｒ・ｍｍ〔重量法〕）水溶液に代えたこと以外、実施例１と同様にして、支持体／成分Ａ含有層／第１隔離層／第２隔離層／成分Ｂ含有層に構成されたサンプル３を得ると共に、同様の評価を行なった。
【００９７】
【表１】

【００９８】
上記表１に示すように、成分Ａを保護する第１隔離層に隣接して更に透湿度２０ｇ／ｍ^２・２４ｈｒ・ｍｍ以下の第２隔離層を設けて成分Ａ及びＢの間に二層構造の隔離層を形成した実施例では、成分Ａを保護する第１隔離層の物質透過性能の湿度依存が抑えられ、湿度に起因する発色バラツキを抑制することができた。一方、第２隔離層を設けずに単層の隔離層を設けた比較例１、並びに第２隔離層を構成するポリマー成分の透湿度が２０ｇ／ｍ^２・２４ｈｒ・ｍｍを超える比較例２では、隔離層における物質透過性能（同濃度を得るのに要する熱量）が湿度差で大きくなり、大きな発色バラツキを生じた。
【００９９】
【発明の効果】
本発明によれば、使用環境の湿度変動の影響を受けることなく安定的に画像を形成することができる感熱記録材料を提供することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat-sensitive recording material, and more particularly to a heat-sensitive recording material in which the influence on color developability due to humidity fluctuations in the use environment is suppressed.
[0002]
[Prior art]
Various methods for forming microcapsules are conventionally used, for example, a method using coacervation of a hydrophilic wall-forming material (for example, see Patent Document 1) or an interfacial polymerization method (for example, Patent Documents 2 to 4). A method using polymer precipitation (for example, see Patent Document 5), a method using an isocyanate polyol wall material (for example, see Patent Document 6), a method using an isocyanate wall material (for example, see Patent Document 7), urea-formaldehyde , A method using a urea formaldehyde-resorcinol wall forming material (for example, see Patent Document 8), a method using a wall forming material such as melamine-formaldehyde resin, hydroxybrovir cellulose (for example, see Patent Document 9), monomer polymerization In situ method (for example, see Patent Document 10), electrolytic content Cooling method (e.g., see Patent Document 11), a spray drying method (for example, see Patent Document 12), etc. are known.
[0003]
Specifically, in the method using the interfacial polymerization method, an oil phase in which a core substance is dissolved or dispersed in a hydrophobic organic solvent is mixed with an aqueous phase containing a water-soluble polymer, and emulsified and dispersed by a homogenizer or the like. It can be encapsulated by forming a microcapsule wall made of a polymer substance by heating and causing a polymer formation reaction at the oil-water interface. This interfacial polymerization method is widely used because of the advantage that microcapsules having good storage performance can be obtained in a short time and with a uniform particle size.
[0004]
On the other hand, the heat-sensitive recording material contains, for example, a coloring first component and a coloring second component that reacts with the coloring component in a separated state and reacts these two components when heated to form an image. In general, one of the two components is encapsulated in a microcapsule to form a separated state. However, the above-mentioned heat-sensitive recording material is used in various environments, and there is a problem that the color density varies depending on the humidity environment during printing due to the influence of humidity.
[0005]
As a technique for enhancing resistance to moisture and humidity, a double wall microcapsule having a primary wall made of an amino resin and a secondary wall made of a polyion complex of a cationic polyamide-epihalohydrin resin and polystyrene sulfonic acid is described. (See, for example, Patent Document 13). However, there is a problem that the suitability for production is not sufficient for use in image formation, and a technique for obtaining moisture resistance while maintaining the suitability for production has been demanded.
[0006]
In addition, the microcapsule has a substance-separating action on the microcapsule wall that prevents contact between the inside and outside of the capsule at room temperature, and the inside and outside of the capsule can be contacted only when heat and / or pressure is applied above a certain value. It is like that. This phenomenon can be controlled to some extent as a change in the physical properties of the capsule by appropriately selecting the material of the capsule wall, the capsule core substance (substance contained in the capsule), additives, etc. It was difficult to suppress variations in color density (density variation) while maintaining color development performance that could be tolerated.
[0007]
[Patent Document 1] US Pat. No. 2,800,547
[Patent Document 2] US Pat. No. 3,287,154
[Patent Document 3] British Patent No. 990443
[Patent Document 4] Japanese Patent Publication No. 38-19574
[Patent Document 5] US Pat. No. 3,418,250
[Patent Document 6] US Pat. No. 3,796,669
[Patent Document 7] US Pat. No. 3,914,511
[Patent Document 8] US Patent No. 4001140
[Patent Document 9] US Pat. No. 4,025,455
[Patent Document 10] Japanese Patent Publication No. 36-9168
[Patent Document 11] British Patent No. 952807
[Patent Document 12] US Pat. No. 3,111,407
[Patent Document 13] JP-A-5-7767
[0008]
[Problems to be solved by the invention]
In particular, when using an interfacial polymerization method for microencapsulation, when the isocyanate is used as the capsule wall forming material for forming the microcapsules, the physical properties of the microcapsules formed are highly dependent on humidity.
The present invention has been made in view of the above, and an object of the present invention is to provide a heat-sensitive recording material capable of stably forming an image without being affected by fluctuations in humidity of the use environment. The task is to do.
[0009]
[Means for Solving the Problems]
In the present invention, in particular, polyurethane / urea thermoresponsive microcapsules are highly dependent on humidity. Among the coating polymers covering the microcapsules encapsulating component A, the moisture permeability of the coating polymer not in contact with component A varies in concentration due to changes in humidity. It was achieved based on the knowledge that it is important.
Means for solving the above-mentioned problems are as follows.
[0010]
<1> A component A, a component B that develops the color of component A, and an isolation layer that isolates component A and component B, and reacting component B that has passed through the isolation layer with component A A heat-sensitive recording material to be formed, wherein the isolation layer is composed of a multilayer structure of at least two layers composed of mutually different polymer components, and the polymer component constituting the layer not contacting the component A of the isolation layer, Moisture permeability at 0% RH / 90% RH is 20 g / m²A heat-sensitive recording material characterized by being 24 hr · mm or less.
[0011]
<2> The heat-sensitive recording material according to <1>, wherein the layer that does not contact the component A of the isolation layer is a layer that contacts the component B. That is, among the layers not in contact with component A, the layer in contact with component B has a moisture permeability of 20 g / m at 0% RH / 90% RH.²It is effective to use a polymer component of 24 hr · mm or less.
[0012]
<3> The heat-sensitive recording material according to <2>, wherein the isolation layer constitutes a capsule wall of a microcapsule enclosing the component A, and a layer not in contact with the component A forms the outermost layer of the capsule wall. is there. That is, when a microcapsule that encloses component A is formed by a multi-layered separation layer, the outermost layer farthest from component A has a moisture permeability of 20 g / m at 0% RH / 90% RH.²-It can comprise suitably using a polymer component of 24 hr * mm or less.
[0013]
<4> The heat-sensitive recording material according to any one of <1> to <3>, wherein a polymer main component constituting at least one layer excluding the layer in contact with the component B of the isolation layer is a urethane / urea polymer. It is. That is, a mode in which a layer surface mainly composed of a urethane / urea polymer is covered with a layer in contact with the component B (for example, the outermost layer of the microcapsule) is preferable.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The heat-sensitive recording material of the present invention contains two color-forming components (components A and B) that react with each other to form a color with a multi-layered separation layer interposed, and at least does not contact with the component A that does not pass through the separation layer. The water vapor permeability at 0% RH / 90% RH of the polymer constituting one layer is 20 g / m.²-It is configured as 24 hr · mm or less. Hereinafter, the heat sensitive recording material of the present invention will be described in detail.
[0015]
The heat-sensitive recording material of the present invention comprises component A, component B that develops color of component A, and an isolation layer that isolates component A and component B, and component B that has passed through the isolation layer when heated is component A. And forming a dye component to form an image. For example, it is constituted by providing at least one recording layer on the support having the component B outside the microcapsules enclosing the component A. Can do. At this time, the component A is separated from the component B by using a microcapsule wall (hereinafter also simply referred to as a capsule wall) covering and encapsulating the component A as an isolation layer. For example, the component B reacts with the component A when it passes through the capsule wall. Color.
[0016]
In the present invention, among the components A and B existing through the isolation layer, the component B has a coloring system that reacts with the component A mainly by passing through the isolation layer. A polymer component having moisture permeability, which will be described later, further covers the layer on the component B side (outside of the innermost layer) from the layer in contact (for example, the innermost layer of the capsule wall that directly covers and encloses the component A in the case of microcapsules). Since a layer that is not in contact with the component A used (preferably a layer that is in contact with the component B) is provided, the humidity dependence of the glass transition point of the layer in contact with the component A (for example, the innermost layer of the capsule wall) can be suppressed. Therefore, the heat-sensitive recording material of the present invention is hardly affected by humidity in the usage environment, and can effectively suppress variations in print density due to humidity fluctuations.
[0017]
The isolation layer in the present invention is constituted by a multilayer structure in which at least two layers composed of different polymer components are laminated, and color develops by reacting with the component B that has passed through the isolation layer among the isolation layers having this multilayer structure. At least one layer not in contact with component A has a moisture permeability of 20 g / m at 0% RH / 90% RH.²-It is comprised using the polymer component which is 24 hr * mm or less. That is, for example, when the multilayer structure is composed of two layers, a polymer in which one of the two layers is in contact with component A and the other is in contact with component B, and the other layer in contact with component B has a moisture permeability in the above range. Formed with ingredients. Specifically, for example, when the multi-layer structure is a microcapsule having a two-layered separating layer forming a capsule wall, the outer layer that contacts the component A and further covers the inner layer that encloses it is a polymer component whose moisture permeability is in the above range. Consists of.
[0018]
In addition, when the multilayer structure of the separating layer has a three-layer structure, an intermediate layer is further provided between the inner layer and the outer layer in the two-layer structure. In this case, the component structure and various performances of each layer including the inner layer are included. In consideration of the above, at least one of the outer layer and the intermediate layer is constituted by a polymer component having a moisture permeability in the above range. The same applies to the layers other than the innermost layer when the multilayer structure has a four-layer structure or more.
[0019]
Component A and Component B are separated by a separating layer (for example, capsule wall) and exist in the heat-sensitive recording material, and component B that has passed through the separating layer (for example, capsule wall) acts on component A to form a dye component. However, when the isolation layer is composed of three or more layers, the moisture permeability not in contact with the component A is 20 g / m.²It is preferable to form a layer having a thickness of 24 hr · mm or less as the outermost layer farthest from the component A when the layer in contact with the component B, that is, for example, when the three-layered separation layer forms a capsule wall.
[0020]
The isolation layer having the multilayer structure configured as described above is formed using different polymer components in the layers constituting the multilayer. The polymer components different from each other are 20 g / m as constituting a layer not in contact with component A.²The polymer component having the above moisture permeability of 24 hr · mm or less is appropriately selected, and the polymer component constituting the layer in contact with the component A (and other layers not in contact with the component A) has film properties such as material permeability during heating. It can be selected as appropriate in consideration. For example, when the multilayer structure is constituted by two layers, the other layer can be constituted by a polymer component different in kind from the polymer component constituting the one layer. At this time, the other layer may be configured to include one polymer layer, and the other layer may include a polymer component of the other layer, or may include other polymer components. Furthermore, when the multilayer structure is composed of three or more layers, it is sufficient that at least two layers are composed of different types of polymer components.
[0021]
The “moisture permeability at 0% RH / 90% RH” according to the present invention can be measured by a method (gravimetric method) based on JIS Z0208-1976. That is, with a relative humidity difference of 90%, a thickness of 0.1 mm and an area of 1 m²Of water vapor passing through the sample in 24 hours [g / m²· 24 hr · mm]. Hereinafter, it is also simply referred to as “moisture permeability”.
In the present invention, the moisture permeability is 20 g / m.²· 24 hr · mm or less, particularly preferably 15 g / m²24 hr · mm or less, most preferably 5 g / m²・ It is 24 hr · mm or less.
[0022]
The above moisture permeability is 20 g / m²Examples of the polymer component having 24 hr · mm or less include, for example, cellulose acetate, hydrochloric acid rubber, cellulose triacetate, polyimide, polycarbonate, polyester (for example, polyethylene terephthalate), ionomer, polyimide, fluorine-based resin (for example, poly-4-fluoro Ethylene, poly-3-fluorochloroethylene, etc.), polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, and the like. Each layer constituting the isolation layer can be suitably formed using any one of these polymer components, or using any one of these polymer components as a main component and a mixed system with other polymer components.
[0023]
Layers other than the layer that does not contact component A using the polymer component having moisture permeability (preferably the layer that contacts component B), that is, the layer that contacts component A and the other layer that does not contact component A (that is, the above-mentioned permeability) Layers not using a polymer component having humidity include, for example, urethane resin, urea resin, amide resin, ester resin, polycarbonate, urea-formaldehyde resin, melamine resin, polystyrene, styrene methacrylate copolymer, styrene- It can comprise using polymer components, such as an acrylate copolymer. Two or more of these polymer components can be used in combination.
[0024]
In the present invention, at least one of the constituent layers of the isolation layer excluding the layer in contact with component B (for example, the outermost layer farthest from the component A contained when the isolation layer forms a capsule wall) is a urethane / urea polymer. It is desirable that it is a layer containing as a main component because the effects of the present invention are effectively exhibited. For example, when the separation layer has a two-layer structure, the layer in contact with the component A (for example, the innermost layer of the capsule wall directly covering and encapsulating the component A in the case of microcapsules) is composed mainly of a urethane / urea polymer. Furthermore, the layer (outermost layer of the capsule wall) in contact with component B is 20 g / m in moisture permeability.²-It can comprise using a polymer component of 24 hr * mm or less, and another polymer component may further contain in these two layers.
[0025]
When the heat-sensitive recording material of the present invention is constituted by providing at least one recording layer on a support, microcapsules in which component A (or component B) is encapsulated by a capsule wall (separating layer) having a multilayer structure, Prepare a coating solution containing component B (or component A) outside the microcapsule and, if necessary, an organic base and other components, and apply and dry the coating solution on a support such as paper or a synthetic resin film. It can produce by doing.
[0026]
The application of the coating liquid can be appropriately selected from known coating methods, and examples thereof include bar coating, blade coating, air knife coating, gravure coating, roll coating coating, spray coating, dip coating, and curtain coating. It is done. The dry coating amount of the recording layer after coating and drying is 2.5 to 30 g / m.²Is preferred.
[0027]
The method for forming an isolation layer in the present invention will be described by taking an isolation layer having a two-layer structure including a first isolation layer and a second isolation layer as an example.
For example, when the heat-sensitive recording material of the present invention has an A layer containing component A and a B layer containing component B on the support, the A layer (or B layer) / first isolation layer on the support. The isolation layer can be provided by forming / second isolation layer / B layer (or A layer) in order from the support side. Further, when the isolation layer forms a capsule wall constituting a microcapsule containing component A (or component B), it can be suitably provided as in the following example.
[0028]
That is, a capsule wall forming step for forming a capsule inner wall forming a first isolation layer with a first polymer component in the liquid composition; A modification step of modifying the surface of the capsule inner wall (first isolation layer) with the second polymer component to form the capsule outer wall (second isolation layer) by further adding and polymerizing the monomer) It can carry out suitably by the method of including. The isolation layer here has a two-layer structure of a first isolation layer and a second isolation layer.
[0029]
Hereinafter, each step will be described in detail.
-Capsule wall formation process-
The capsule wall forming step is a step of forming a first isolation layer (capsule inner wall) with the first polymer component in the liquid composition. In the present invention, a conventionally known microencapsulation method can be used for the formation of the capsule wall. For example, a method using coacervation of a hydrophilic wall forming material described in U.S. Pat. Nos. 2,800,457 and 2,800,458, Interfacial polymerization methods described in U.S. Pat. No. 3,287,154, British Patent No. 990443, Japanese Patent Publication Nos. 38-19574, 42-446, 42-771, etc., U.S. Pat. Nos. 3,418,250 and 3,660,304. A method by polymer precipitation, a method using an isocyanate polyol wall material described in US Pat. No. 3,796,669, a method using an isocyanate wall material described in US Pat. No. 3,914,511, US Pat. Nos. 4,001,140, 4,087,376 and 4,089,802 Urea-formaldehyde system, urea described A method using a lumaldehyde-resorcinol-based wall forming material, a method using a wall forming material such as melamine-formaldehyde resin and hydroxybrovir cellulose described in US Pat. No. 4,025,455, Japanese Patent Publication No. 36-9168, Japanese Patent Application Laid-Open No. 51- In situ method by polymerization of monomer described in No. 9079, electrolytic dispersion cooling method described in British Patent Nos. 952807 and 965074, spray drying method described in US Pat. No. 3,111,407 and British Patent No. 930422, The methods described in JP-A-7-73069, JP-A-4-101858 and JP-A-9-263057 can be appropriately selected and used.
[0030]
The method of forming the capsule wall (method of microencapsulation) is not limited to these, but an interfacial polymerization method can be suitably employed. The interfacial polymerization method refers to an oil phase prepared by dissolving or dispersing a core substance (for example, component A which is a coloring component) serving as a capsule core in a hydrophobic organic solvent, and water containing a water-soluble polymer dissolved therein. After mixing with the phase and emulsifying and dispersing by means such as a homogenizer, heating causes a polymer formation reaction at the oil droplet interface, thereby forming a capsule inner wall of the polymer substance (first polymer component). is there. The interfacial polymerization method can form capsules with a uniform particle size within a short time, and can provide excellent raw storage properties when used as a heat-sensitive recording material. Hereinafter, a method for forming a capsule inner wall serving as the first isolation layer (a microencapsulation method) will be described by taking an interfacial polymerization method as an example.
[0031]
As a microcapsule suitable for a thermosensitive recording material, at normal temperature, contact between substances inside and outside the capsule is hindered by the substance isolating action of the capsule inner wall, and only when heat (and / or pressure) is applied above a certain value, The thing which can contact the substance inside and outside a capsule is mentioned. This phenomenon can be freely controlled as a change in the physical properties of the capsule by appropriately selecting the material of the inner wall of the capsule, the capsule core substance (substance contained in the capsule), the additive, and the like. As described above, by providing the capsule outer wall as the second isolation film so as to cover the capsule inner wall as the first isolation film, it is possible to suppress changes in the physical properties of the capsule inner wall due to humidity fluctuations.
[0032]
At this time, the details of the first polymer component that becomes the material of the capsule inner wall (first isolation layer) are as described above, for example, urethane resin, urea resin, amide resin, ester resin, polycarbonate, urea. -The polymer component such as formaldehyde resin, melamine resin, polystyrene, styrene methacrylate copolymer, styrene-acrylate copolymer, etc., and also the second polymer component that becomes the material of the capsule outer wall (second separating layer), The moisture permeability described above is 20 g / m²-Each polymer component which is 24hr * mm or less is mentioned.
[0033]
The microcapsules by the interfacial polymerization method are formed by adding an oil phase prepared by dissolving or dispersing a core substance in a hydrophobic organic solvent into an aqueous phase, emulsifying and dispersing, and then heating. At this time, an aqueous solution in which a water-soluble polymer is dissolved is used for the aqueous phase in which the oil phase is emulsified and dispersed. Examples of the water-soluble polymer contained in the aqueous phase include gelatin, polyvinyl alcohol and the like, and details will be described later.
[0034]
The first polymer component constituting the capsule inner wall (first isolation layer) can be suitably formed particularly using isocyanate. For example, when polyurethane is used as a capsule wall material, a water-soluble polymer aqueous solution (aqueous phase) or an encapsulated polyvalent isocyanate and a second substance that reacts therewith to form a capsule wall (eg, polyol, polyamine) are encapsulated. By mixing in an oily medium (oil phase), emulsifying and dispersing in water, and then heating, a polymer formation reaction occurs at the oil droplet interface, and a capsule wall can be formed.
[0035]
US Pat. Nos. 3,281,383, 3,773,695, 3,793,268, JP-B-48-40347, JP-A-49-24159, JP-A-48-80191 are exemplified as the polyvalent isocyanate and the polyol and polyamine which are reacted with the polyvalent isocyanate. 48-84086 can be used. The polyvalent isocyanate compound is preferably a compound having a trifunctional or higher functional isocyanate group, but may be a bifunctional isocyanate compound. Specifically, diisocyanates such as xylene diisocyanate and hydrogenated products thereof, hexamethylene diisocyanate, tolylene diisocyanate and hydrogenated products thereof, isophorone diisocyanate and the like, and dimers or trimers thereof (burette or isocyanate). Nurate), other polyfunctional adducts such as trimethylolpropane polyols and bifunctional isocyanates such as xylylene diisocyanate, adducts of trimethylolpropane polyols and xylylene diisocyanate and other bifunctional isocyanates Examples thereof include a compound in which a high molecular weight compound such as polyether having active hydrogen such as polyethylene oxide is introduced, and a formalin condensate of benzene isocyanate.
[0036]
Specific examples of the polyol or polyamine include propylene glycol, glycerin, trimethylolpropane, triethanolamine, sorbitol, hexamethylenediamine and the like.
In an emulsified dispersion in which an oil phase is added to an aqueous phase in the interfacial polymerization method, a polyurea polymerization reaction can occur at the interface between the oil phase and the aqueous phase to form a polyurea wall, and a polyol and / or polyamine can be added. A polyurethane wall is then formed.
[0037]
In the present invention, when forming a microcapsule enclosing component A, the encapsulated component A may be present in a solution state or in a solid state in the capsule. In the case of producing a thermosensitive recording material, when the color forming component is encapsulated in a solution state, the color developing component such as an electron donating colorless dye or a diazonium salt compound may be encapsulated in an organic solvent. .
[0038]
In general, the organic solvent can be appropriately selected from high-boiling solvents such as phosphate ester, phthalate ester, acrylic acid ester, methacrylic acid ester, other carboxylic acid ester, fatty acid amide, alkylated biphenyl, Alkylated terphenyl, chlorinated paraffin, alkylated naphthalene, diallylethane, compounds solid at room temperature, oligomer oil, polymer oil, and the like are used. Specifically, JP-A-59-178451, JP-A-59-178455, JP-A-59-178457, JP-A-60-242894, JP-A-63-85633, JP-A-6-194825, JP-A-7-13310 and the like. Examples thereof include organic solvents described in JP-A Nos. 7-13311 and 9-106039 and Japanese Patent Application No. 62-75409. Further, when encapsulating, a so-called oilless capsule may be used without using the organic solvent.
As the usage-amount of the said organic solvent, 1-500 mass parts is preferable with respect to 100 mass parts of coloring components.
[0039]
Further, when the coloring component to be encapsulated in the organic solvent has low solubility, a low-boiling solvent having high solubility can be used in combination as an auxiliary solvent. On the other hand, the low boiling point solvent can be used without using the organic solvent. Examples of the low boiling point solvent include ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, methylene chloride and the like.
[0040]
After the oil phase is introduced into the aqueous phase, it is emulsified and dispersed by means such as a homogenizer. The water-soluble polymer added to the aqueous phase acts as a protective colloid that can make the dispersion uniform and easy. And acts as a dispersion medium for stabilizing the emulsified and dispersed aqueous solution. The water-soluble polymer contained as the protective colloid can be appropriately selected from known anionic polymers, nonionic polymers, and amphoteric polymers.
[0041]
As the anionic polymer, any of natural and synthetic ones can be used. For example, —COO—, —SO₂Examples thereof include those having a linking group such as-. Specifically, natural products such as gum arabic, alginic acid, and bectin; semi-synthetic products such as gelatin derivatives such as carboxymethyl cellulose and phthalated gelatin; sulfated starch, sulfated cellulose, and lignin sulfonic acid; maleic anhydride (hydrolysis) And synthetic products such as copolymers, acrylic acid (methacrylic acid) polymers and copolymers, vinylbenzenesulfonic acid polymers and copolymers, and carboxy-modified polyvinyl alcohol.
Examples of the nonionic polymer include polyvinyl alcohol, hydroxyethyl cellulose, and methyl cellulose.
Examples of the amphoteric polymer include gelatin. Of these, gelatin, gelatin derivatives, and polyvinyl alcohol are preferable.
The water-soluble polymer is used as an aqueous solution of 0.01 to 10% by mass.
[0042]
Moreover, in order to carry out emulsification dispersion more uniformly and to make a more stable dispersion, a surfactant can be added to at least one of the oil phase and the water phase. The surfactant can be appropriately selected from known surfactants for emulsification. For example, anionic or nonionic surfactants can act as protective colloids as described above and precipitate. And those that do not cause aggregation can be appropriately selected and used. Specific examples include sodium alkylbenzene sulfonate, sodium alkyl sulfate, dioctyl sodium sulfosuccinate, polyalkylene glycol (for example, polyoxyethylene nonylphenyl ether), and the like.
The addition amount of the surfactant is preferably 0.1% to 5%, more preferably 0.5% to 2% with respect to the oil phase mass.
[0043]
After emulsification and dispersion, the emulsion is heated to 30 to 70 ° C. for the purpose of promoting the capsule wall formation reaction. Thereby, the capsule inner wall which consists of a 1st polymer component in a liquid composition, ie, the 1st isolation layer which comprises an isolation layer, can be formed. Further, during the reaction, in order to prevent the capsules from aggregating, it is necessary to add water to reduce the collision probability between the capsules or to perform sufficient stirring.
Further, a dispersion for preventing aggregation may be added separately during the reaction.
The end point of the capsule wall formation reaction can be regarded as an approximate end point when the generation of carbon dioxide gas is observed with the progress of the polymerization reaction.
Usually, by performing the reaction for several hours, microcapsules encapsulating the coloring component can be obtained.
[0044]
The average particle diameter of the microcapsules before being modified with the second polymer component and forming the second isolation layer is preferably 10 μm or less, and more preferably 2 μm or less from the viewpoint of obtaining high resolution. In addition, if the formed microcapsule diameter is too small, the surface area with respect to a certain solid content becomes large and a large amount of wall agent is required. Therefore, the average particle diameter is preferably 0.1 μm or more.
[0045]
-Modification process-
In the modification step, a monomer having an ethylenically unsaturated bond (monomer in the present invention) is further added to the liquid composition in which the capsule inner wall (first isolation layer) is formed (microencapsulation) and further polymerized. The outer wall of the capsule forming the second isolation layer is formed by modifying the surface of the inner wall of the capsule with the second polymer component having the above-mentioned moisture permeability. At this time, a separating layer having a multilayer structure is constituted by the capsule inner wall and the capsule outer wall.
[0046]
The second polymer component can be formed using a monomer having an ethylenically unsaturated bond (monomer in the present invention). The monomer in the present invention can be appropriately selected from monomers having an ethylenically unsaturated bond as long as a polymer component satisfying the moisture permeability described above can be formed. Specific examples include styrene, vinyl chloride, vinylidene chloride and the like. Among these, it is particularly preferable to use a monomer having a plurality of vinyl groups in the molecule, and examples of such a monomer include divinylbenzene.
[0047]
The molecular weight of the monomer in the present invention is not particularly limited and may be selected according to the desired purpose. For example, the molecular weight is preferably about 100 to 5000, more preferably about 100 to about 2000.
[0048]
As described above, the second polymer component formed by the monomer in the present invention is added to the liquid composition in which the capsule inner wall (first isolation layer) is formed by further adding and polymerizing the monomer in the present invention. It can be attached (modified) to the inner wall of the capsule. Thereby, the second isolation layer is formed. As the polymerization method of the monomer in the present invention, a known polymerization method can be appropriately selected, and radical polymerization is particularly preferable.
In addition, the reaction temperature in the polymerization reaction of the monomer in the present invention can be appropriately selected.
[0049]
The layer thickness of the second isolation layer varies depending on the humidity dependency of the first isolation layer and various performances as a capsule, but is preferably 0.01 to 10 times the layer thickness of the first isolation layer, It is more preferably 0.1 to 2 times.
Moreover, it is desirable to add the monomer in the present invention so as to have a desired layer thickness with respect to the first isolation layer from the viewpoint of developing various performances as a capsule.
[0050]
In order to polymerize the “monomer in the present invention”, a polymerization initiator can be used. As the polymerization initiator, any of a photopolymerization initiator, a thermal polymerization initiator, a redox initiator, and the like can be used. Specific examples include the following.
[0051]
Examples of the photopolymerization initiator include benzophenone, 4,4-bis (dimethylamino) benzophenone, 4-methoxy-4′-dimethylaminobenzophenone, 4,4′-dimethoxybenzophenone, 4-dimethylaminobenzophenone, 4- Dimethylaminoacetophenone, benzylanthraquinone, 2-tert-butylanthraquinone, 2-methylanthraquinone, xanthone, thioxanthone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, fluorenone, acridone, bis (2,4,6-trimethylbenzoyl) -Bisacylphosphine oxides such as phenylphosphine oxide, and acylphosphine oxides such as 2,4,6-trimethylbenzoyl-diphenylphosphine oxide. Family ketones;
[0052]
Benzoin and benzoin ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether and benzoin phenyl ether; 2- (o-chlorophenyl) -4,5-diphenylimidazole duplex, 2- (o-chlorophenyl) -4, 5-di (m-methoxyphenyl) imidazole duplex, 2- (o-fluorophenyl) -4,5-diphenylimidazole duplex, 2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer, 2,4,6-triarylimidazole duplexes such as 2- (p-methoxyphenyl) -4,5-diphenylimidazole duplexes; polyhalogens such as carbon tetrabromide, phenyltribromomethylsulfone, phenyltrichloromethylketone Compound; JP 59-133 No. 28, JP-B-57-1819, JP-B-57-6096, compounds described in U.S. Patent No. 3,615,455;
[0053]
2,4,6-tris (trichloromethyl) -S-triazine, 2-methoxy-4,6-bis (trichloromethyl) -S-triazine, 2-amino-4,6-bis (trichloromethyl) -S- S-triazine derivatives having a trihalogen-substituted methyl group described in JP-A No. 58-29803, such as triazine and 2- (P-methoxystyryl) -4,6-bis (trichloromethyl) -S-triazine;
[0054]
Methyl ethyl ketone peroxide, cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, benzoyl peroxide, ditertiary-butyldiperoxyisophthalate, 2,5-dimethyl-2,5-di (benzoylberoxy) hexane, Tertiary butyl baroxybenzoate, a, a′-bis (tertiary butyl baroxyisopropyl) benzene, dicumyl peroxide, 3,3 ′, 4,4′-tetra- (tertiary butyl peroxycarbonyl) benzophenone, etc. An organic peroxide described in JP-A-59-189340;
[0055]
Azinium salt compounds described in US Pat. No. 4,743,530; tetraphenylammonium salt of triphenylbutyrate borate, tetrabutylammonium salt of triphenylbutyrate borate, tetramethylammonium salt of tri (P-methoxyphenyl) butyrateborate, etc. And organic boron compounds described in European Patent No. 023587; other diaryliodonium salts and iron allene complexes.
[0056]
Moreover, what combined 2 or more types of compounds is also known, and these can also be used for this invention. Examples of combinations of two or more compounds include a combination of 2,4,5-triarylimidazole dimer and mercaptobenzoxazole, etc., 4,4′- described in US Pat. No. 3,427,161. A combination of bis (dimethylamino) benzophenone and benzophenone or benzoin methyl ether, benzoyl-N-methylnaphthothiazoline and 2,4-bis (trichloromethyl) -6- (4′-) described in US Pat. No. 4,239,850 Combination of methoxyphenyl) -triazole, combination of dialkylaminobenzoate and dimethylthioxanthone described in JP-A-57-23602, 4,4′-bis (dimethylamino) of JP-A-59-78339 ) Benzophenone, benzophenone and polyhalogenated methyl compounds Like three kinds of combinations such as is.
[0057]
Furthermore, as other photopolymerization initiators, organic borate compounds described in JP-A-62-143044, JP-A-9-188585, JP-A-9-188686, JP-A-9-188710, etc., or cationic Examples thereof include spectral sensitizing dye-based borate compounds obtained from dyes.
[0058]
Examples of the thermal polymerization initiator include 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, 2,2′-azobis-2-amidinopropane dihydrochloride, 1,1′azobiscyclohexane. Preferred examples include -1-carbonitrile, 2,2′-azobis-2,4-dimethylvaleronitrile, and 2,2′-azobisisobutyronitrile (AIBN). Examples of the redox initiator include hydrogen peroxide-Fe.²⁺Salt, persulfate-NaHSO₃And benzoyl peroxide-dimethylaniline. Furthermore, the following compounds are mentioned. Note that the present invention is not limited to these.
[0059]
[Chemical 1]

[0060]
[Chemical 2]

[0061]
As content of the said polymerization initiator, 0.001-0.1 mass part is preferable with respect to 1 mass part of monomers in this invention, and 0.01-0.05 mass part is more preferable. Furthermore, a cationic or anionic polymerizable surfactant can be used as the polymerizable surfactant. In this case, a water-soluble polymerization initiator having a charge opposite to that of the polymerizable surfactant is used. preferable.
[0062]
Further, the timing of adding the monomer in the present invention to the liquid composition in the modification step is not particularly limited as long as it is after the capsule wall formation in the capsule wall formation step. For example, after the capsule inner wall formation (emulsion polymerization) After) the monomer may be added continuously. Further, the second polymer component may be either a single species or two or more species, and can be appropriately determined according to the desired performance. Further, if necessary, during the polymerization reaction of the monomer in the present invention, a monomer of the present invention of a different type from that of the monomer of the present invention is further added and encapsulated in a hetero type with two different second polymer components The wall may be modified.
[0063]
Next, examples of the component A and the component B contained as the color forming component of the thermosensitive recording material include the following combinations. In each of the following combinations, the former indicates component A and the latter indicates component B.
(A) A combination of an electron-donating dye precursor and an electron-accepting compound.
(A) A combination of a diazonium salt compound and a coupling component (hereinafter appropriately referred to as “coupler compound”).
(C) A combination of an organic acid metal salt such as silver behenate or silver stearate and a reducing agent such as protocatechinic acid, spiroindane or hydroquinone.
(D) A combination of a long-chain fatty acid iron salt such as ferric stearate or ferric myristate and a phenol such as tannic acid, gallic acid or ammonium salicylate.
(E) Organic acid heavy metal salts such as nickel, cobalt, lead, copper, iron, mercury and silver salts such as acetic acid, stearic acid and palmitic acid, and alkali metals or alkaline earth such as calcium sulfide, strontium sulfide and potassium sulfide A combination of a metal sulfide or a combination of the organic acid heavy metal salt and an organic chelating agent such as s-diphenylcarbazide or diphenylcarbazone.
[0064]
(F) A combination of a heavy metal sulfate such as a sulfate such as silver, lead, mercury or sodium and a sulfur compound such as sodium tetrathionate, sodium thiosulfate or thiourea.
(G) A combination of an aliphatic ferric salt such as ferric stearate and an aromatic polyhydroxy compound such as 3,4-hydroxytetraphenylmethane.
(H) A combination of an organic acid metal salt such as silver oxalate or mercury oxalate and an organic polyhydroxy compound such as polyhydroxy alcohol, glycerin or glycol.
(G) A combination of a ferric salt of a fatty acid such as ferric pelargonate or ferric laurate and a thiocesylcarbamide or isothiocecilcarbamide derivative.
(Co) A combination of a lead salt of an organic acid such as lead caproate, lead pelargonate or lead behenate and a thiourea derivative such as ethylenethiourea or N-dodecylthiourea.
[0065]
(Sa) A combination of a higher aliphatic heavy metal salt such as ferric stearate or copper stearate and zinc dialkyldithiocarbamate.
(B) Those that form an oxazine dye such as a combination of resorcin and a nitroso compound.
(Su) A combination of a formazan compound and a reducing agent and / or a metal salt.
(C) A combination of a protected dye (or leuco dye) precursor and a deprotecting agent.
(So) A combination of an oxidizing color former and an oxidizing agent.
(Ta) A combination of phthalonitriles and diiminoisoindolines. (A combination that produces phthalocyanine.)
(H) A combination of isocyanates and diiminoisoindolines (a combination that produces a colored pigment).
(Iv) A combination of a pigment precursor and an acid or a base (a combination that forms a pigment).
[0066]
Among these, a combination of a substantially colorless electron donating dye precursor (hereinafter referred to as an electron donating colorless dye) and an electron accepting compound, or a combination of a diazonium salt compound and a coupler compound is preferable. In particular, an electron-donating colorless dye or a diazonium salt compound can be suitably used as Component A.
[0067]
As the electron donating colorless dye, conventionally known dyes can be used, and specific examples thereof include the following compounds. However, the present invention is not limited to these. Specifically, phthalide compounds, fluoran compounds, phenothiazine compounds, indolylphthalide compounds, leucooramine compounds, rhodamine lactam compounds, triphenylmethane compounds, triazene compounds, spiropyran compounds, pyridine Examples thereof include various compounds such as phosphines, pyrazine compounds, and fluorene compounds.
[0068]
Examples of the phthalide compounds include US Reissued Patent No. 23,024, US Pat. Nos. 3,491,111, 3,491,112, 3,491,116, and 3, 509,174, specifically, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3,3-bis (p-diethylamino-o-butoxy) Phenyl) -4-azaphthalide, 3- (p-diethylamino-o-butoxyphenyl) -3- (1-pentyl-2-methylindol-3-yl) -4-azaphthalide, 3- (p-dipropylamino- o-methylphenyl) -3- (1-octyl-2-methylindol-3-yl) -5-aza (or -6-aza, or -7-aza) phthalide.
[0069]
Examples of the fluorane compound include U.S. Pat. Nos. 3,624,107, 3,627,787, 3,641,011, 3,462,828, and 3,681. , 390, 3,920,510, 3959,571, specifically, 2- (dibenzylamino) fluorane, 2-anilino-3-methyl-6 -Diethylaminofluorane, 2-anilino-3-methyl-6-dibutylaminofluorane, 2-anilino-3-methyl-6-N-ethyl-N-isoamylaminofluorane, 2-anilino-3-methyl-6 -N-methyl-N-cyclohexylaminofluorane, 2-anilino-3-chloro-6-diethylaminofluorane, 2-anilino-3-methyl-6-N-ethyl-N-isobu Ruaminofluorane, 2-anilino-6-dibutylaminofluorane, 2-anilino-3-methyl-6-N-ethyl-N-tetrahydrofurfurylaminofluorane, 2-anilino-3-methyl-6-pi Peridinoaminofluorane, 2- (o-chloroanilino) -6-diethylaminofluorane, 2- (3,4-dichloroanilino) -6-diethylaminofluorane and the like can be mentioned.
[0070]
Examples of phenothiazine compounds include benzoyl leucon methylene blue and p-nitrobenzyl leucomethylene blue. Examples of leucooramine compounds include 4,4′-bis-dimethylaminobenzhydrin benzyl ether, N -Halophenyl-leucooramine, N-2,4,5-trichlorophenylleucooramine and the like. Examples of rhodamine lactam compounds include rhodamine-B-anilinolactam and rhodamine- (p-nitrino) lactam. Can be mentioned. Examples of spiropyran compounds include compounds described in U.S. Pat. No. 3,971,808. Specifically, 3-methyl-spiro-dinaphthopyrans, 3-ethyl-spiro-dinaphthopyrans 3,3 '-Dichloro-spiro-dinaphthopyrans, 3-benzylspiro-dinaphthopyrans, 3-methyl-naphtho- (3-methoxy-benzo) spiropyrans, 3-propyl-spiro-dibenzopyrans, etc., pyridine-based and pyrazine-based compounds Examples thereof include compounds described in U.S. Pat. Nos. 3,775,424, 3,853,869, and 4,246,318. Examples of the fluorene compound include Japanese Patent Application No. Examples thereof include compounds described in JP-A-61-240989.
[0071]
When a color thermosensitive recording material is used, an electron donating colorless dye for one or more coloring dyes selected from cyan, magenta, and yellow is used. As cyan, magenta, and yellow coloring, those described in U.S. Pat. No. 4,800,149 can be used, and as an electron-donating colorless dye for yellow coloring pigment, U.S. Pat. No. 4,800,148 and the like. The electron-donating colorless dyes for cyan coloring dyes can also be those described in JP-A-63-53542.
[0072]
The content of the electron donating colorless dye is 0.01 to 3 g / m in the recording layer.²Is preferable, 0.1-1 g / m²Is more preferable. When the content is within the above range, a particularly sufficient color density can be obtained, and the suitability for coating does not deteriorate. In the case of a multilayer structure, a plurality of recording layers containing an electron donating colorless dye are stacked in the above range.
[0073]
Examples of the diazonium salt compound include Ar-N.₂ ⁺・ X⁻[Ar represents an aromatic ring group;⁻Represents an acid anion. ] The compound represented by this is mentioned. This diazonium salt compound is a compound that undergoes a coupling reaction with a coupler by heating to cause color development or to decompose by light. The maximum absorption wavelength of these can be controlled by the position and type of the substituent in the Ar portion.
[0074]
Ar in the above formula represents a substituted or unsubstituted aryl group. Examples of the substituent include an alkyl group, an alkoxy group, an alkylthio group, an aryl group, an aryloxy group, an arylthio group, an acyl group, an alkoxycarbonyl group, a carbamoyl group, a carbamide group, a sulfonyl group, a sulfamoyl group, a sulfonamide group, a ureido group, A halogen group, an amino group, a heterocyclic group, a nitro group, a cyano group and the like can be mentioned, and these substituents may be further substituted.
[0075]
The aryl group is preferably an aryl group having 6 to 30 carbon atoms. For example, a phenyl group, a 2-methylphenyl group, a 2-chlorophenyl group, a 2-methoxyphenyl group, a 2-butoxyphenyl group, 2- (2 -Ethylhexyloxy) phenyl group, 2-octyloxyphenyl group, 3- (2,4-di-t-pentylphenoxyethoxy) phenyl group, 4-chlorophenyl group, 2,5-dichlorophenyl group, 2,4,6- Trimethylphenyl group, 3-chlorophenyl group, 3-methylphenyl group, 3-methoxyphenyl group, 3-butoxyphenyl group, 3-cyanophenyl group, 3- (2-ethylhexyloxy) phenyl group, 3,4-dichlorophenyl group 3,5-dichlorophenyl group, 3,4-dimethoxyphenyl group, 3- (dibutylaminocarb) Nylmethoxy) phenyl group, 4-cyanophenyl group, 4-methylphenyl group, 4-methoxyphenyl group, 4-butoxyphenyl group, 4- (2-ethylhexyloxy) phenyl group, 4-benzylphenyl group, 4-aminosulfonyl Phenyl group, 4-N, N-dibutylaminosulfonylphenyl group, 4-ethoxycarbonylphenyl group, 4- (2-ethylhexylcarbonyl) phenyl group, 4-fluorophenyl group, 3-acetylphenyl group, 2-acetylaminophenyl Group, 4- (4-chlorophenylthio) phenyl group, 4- (4-methylphenyl) thio-2,5-butoxyphenyl group, 4- (N-benzyl-N-methylamino) -2-dodecyloxycarbonylphenyl Group, and the like.
Further, these groups may be further substituted with an alkyloxy group, an alkylthio group, a substituted phenyl group, a cyano group, a substituted amino group, a halogen atom, a heterocyclic group, or the like.
[0076]
The content of the diazonium salt compound is 0.01-3 g / m in the recording layer.²Is preferred, 0.02-1.0 g / m²Is more preferable. When the content is within the above range, particularly sufficient color developability can be obtained, and the sensitivity does not decrease and the fixing time does not need to be lengthened.
[0077]
Next, an electron accepting compound that reacts with the electron donating colorless dye and develops a color by reacting with the diazonium salt compound will be described in detail.
Examples of the electron-accepting compound include 3-halo-4-hydroxybenzoic acid described in JP-A-4-226455, methacryloxyethyl ester of benzoic acid having a hydroxy group described in JP-A-63-173682, Acryloxyethyl ester, ester of benzoic acid having hydroxy group and hydroxymethyl styrene described in JP-A-59-83893, JP-A-60-141588, and JP-A-62-99190, hydroxystyrene described in European Patent No. 29323, Examples thereof include compounds that can be synthesized with reference to N-vinylimidazole complexes of zinc halides described in Kaikai 62-1667077 and 62-16708, and electron-accepting compounds described in 63-317558. Of these, 3-halo-4-hydroxybenzoic acid is preferable.
[0078]
Examples of the 3-halo-4-hydroxybenzoic acid include 3-chloro-4-hydroxybenzoic acid ester vinyl phenethyl ester, 3-chloro-4-hydroxybenzoic acid vinyl phenylpropyl ester, and 3-chloro-4-hydroxybenzoic acid ester. Acid- (2-acryloyloxyethyl) ester, 3-chloro-4-hydroxybenzoic acid- (2-methacryloyloxyethyl) ester, 3-chloro-4-hydroxybenzoic acid- (2-acryloyloxypropyl) ester, 3 -Chloro-4-hydroxybenzoic acid- (2-methacryloyloxypropyl) ester, 3-chloro-4-hydroxybenzoic acid- (3-acryloyloxypropyl) ester, 3-chloro-4-hydroxybenzoic acid- (3- Methacryloyloxypropyl) ester, -Chloro-4-hydroxybenzoic acid- (4-acryloyloxybutyl) ester, 3-chloro-4-hydroxybenzoic acid- (4-methacryloyloxybutyl) ester, 3-chloro-4-hydroxybenzoic acid- (5- (Acryloyloxypentyl) ester, 3-chloro-4-hydroxybenzoic acid- (5-methacryloyloxypentyl) ester, 3-chloro-4-hydroxybenzoic acid- (6-acryloyloxyhexyl) ester, 3-chloro-4- Hydroxybenzoic acid- (6-methacryloyloxyhexyl) ester, 3-chloro-4-hydroxybenzoic acid- (8-acryloyloxyoctyl) ester, 3-chloro-4-hydroxybenzoic acid- (8-methacryloyloxyoctyl) ester etc,
[0079]
Styrenesulfonylaminosalicylic acid, vinylbenzyloxyphthalic acid, zinc β-methacryloxyethoxysalicylate, β-acryloxyethoxysalicylic acid zinc, vinyloxyethyloxybenzoic acid, β-methacryloxyethylorcerinate, β-acryloxyethylorceri , Β-methacryloxyethoxyphenol, β-acryloxyethoxyphenol, β-methacryloxyethyl-β-resorcinate, β-acryloxyethyl-β-resorcinate, hydroxystyrenesulfonic acid-N-ethylamide, β-methacryloxypropyl -P-hydroxybenzoate, β-acryloxypropyl-p-hydroxybenzoate, methacryloxymethylphenol, acryloxymethylphenol, methacrylamidepropanesulfone , Acrylamide propane sulfonic acid, beta-methacryloxyethoxy - dihydroxybenzene, beta-acryloxy ethoxy - dihydroxybenzene, .gamma. styrene sulfonyloxy -β- methacryloxy propanoic acid,
[0080]
γ-acryloxypropyl-α-hydroxyethyloxysalicylic acid, β-hydroxyethynylphenol, β-methacryloxyethyl-p-hydroxycinnamate, β-acryloxyethyl-p-hydroxycinnamate, 3,5 distyrene sulfone Acid amidophenol, methacryloxyethoxyphthalic acid, acryloxyethoxyphthalic acid, methacrylic acid, acrylic acid, methacryloxyethoxyhydroxynaphthoic acid, acryloxyethoxyhydroxynaphthoic acid, 3-β-hydroxyethoxyphenol, β-methacryloxyethyl- p-hydroxybenzoate, β-acryloxyethyl-p-hydroxybenzoate, β′-methacryloxyethyl-β-resorcinate, β-methacryloxyethyloxycarbonylhydroxybenzoic acid , Β-acryloxyethyloxycarbonylhydroxybenzoic acid, N, N′-di-β-methacryloxyethylaminosalicylic acid, N, N′-di-β-acryloxyethylaminosalicylic acid, N, N′-di-β -Methacryloxyethylaminosulfonylsalicylic acid, N, N′-di-β-acryloxyethylaminosulfonylsalicylic acid, and metal salts thereof (for example, zinc salts) are preferable.
[0081]
In addition to the above, for example, phenol derivatives, salicylic acid derivatives, metal salts of aromatic carboxylic acids, acidic clay, pentonite, novolac resins, metal-treated novolac resins, metal complexes and the like can also be mentioned. Specifically, JP-B-40-9309, JP-B-45-14039, JP-A-52-140483, JP-A-48-51510, JP-A-57-210886, JP-A-58-87089. JP-A-59-11286, JP-A-60-176795, JP-A-61-95988, and the like. Specifically, the following compounds can be mentioned.
[0082]
Examples of the phenol derivative include 2,2′-bis (4-hydroxyphenyl) propane, 4-t-butylphenol, 4-phenylphenol, 4-hydroxydiphenoxide, 1,1′-bis (3-chloro-4). -Hydroxyphenyl) cyclohexane, 1,1'-bis (4-hydroxyphenyl) cyclohexane, 1,1'-bis (3-chloro-4-hydroxyphenyl) -2-ethylbutane, 4,4'-sec-isooctane Tylidene diphenol, 4,4′-sec-butylidene diphenol, 4-tert-octylphenol, 4-p-methylphenylphenol, 4,4′-methylcyclohexylidenephenol, 4,4′-isopentylidenephenol, Examples include benzyl p-hydroxybenzoate.
[0083]
Examples of the salicylic acid derivative include 4-pentadecyl salicylic acid, 3,5-di (α-methylbenzyl) salicylic acid, 3,5-di (tert-octyl) salicylic acid, 5-octadecylsalicylic acid, 5-α- (p- α-methylbenzylphenyl) ethylsalicylic acid, 3-α-methylbenzyl-5-tert-octylsalicylic acid, 5-tetradecylsalicylic acid, 4-hexyloxysalicylic acid, 4-cyclohexyloxysalicylic acid, 4-decyloxysalicylic acid, 4-dodecyl Examples thereof include oxysalicylic acid, 4-pentadecyloxysalicylic acid, 4-octadecyloxysalicylic acid, and the like, as well as zinc, aluminum, calcium, copper, and lead salts thereof.
[0084]
As content of the said electron-accepting compound, 0.5-20 mass parts is preferable with respect to 1 mass part of electron-donating colorless dye, and 3-10 mass parts is more preferable. When the content of the electron-donating colorless dye is in the above range, a particularly sufficient color density can be obtained, and the sensitivity and coating suitability are not deteriorated.
[0085]
The coupler compound forms a dye by coupling with the diazonium salt compound in a basic atmosphere and / or a neutral atmosphere, and is used in combination of plural kinds according to various purposes such as hue adjustment. be able to. Examples of the coupler compound include resorcin, phloroglucin, 2,3-dihydroxynaphthalene, sodium 2,3-dihydroxynaphthalene-6-sulfonate, 1-hydroxy-2-naphthoic acid morpholinopropylamide, 2-hydroxy-3- Sodium naphthalenesulfonate, 2-hydroxy-3-naphthalenesulfonic acid anilide, 2-hydroxy-3-naphthalenesulfonic acid morpholinopropylamide, 2-hydroxy-3-naphthalenesulfonic acid-2-ethylhexyloxypropylamide, 2-hydroxy- 3-naphthalenesulfonic acid-2-ethylhexylamide, 5-acetamido-1-naphthol, 1-hydroxy-8-acetamidonaphthalene-3,6-disulfonic acid sodium salt, 1-hydroxy-8-acetami 3,6-disulfonic acid dianilide, 1,5-dihydroxynaphthalene, 2-hydroxy-3-naphthoic acid morpholinopropyl amide, 2-hydroxy-3-naphthoic acid octyl amide, 2-hydroxy-3-naphthoic acid anilide,
[0086]
5,5-dimethyl-1,3-cyclohexanedione, 1,3-cyclopentanedione, 5- (2-n-tetradecyloxyphenyl) -1,3-cyclohexanedione, 5-phenyl-4-methoxycarbonyl- 1,3-cyclohexanedione, 5- (2,5-di-n-octyloxyphenyl) -1,3-cyclohexanedione, N, N′-dicyclohexylbarbituric acid, N, N′-di-n-dodecyl Barbituric acid, Nn-octyl-N′-n-octadecylbarbituric acid, N-phenyl-N ′-(2,5-di-n-octyloxyphenyl) barbituric acid, N, N′-bis (Octadecyloxycarbonylmethyl) barbituric acid, 1-phenyl-3-methyl-5-pyrazolone, 1- (2,4,6-trichlorophenyl)- -Anilino-5-pyrazolone, 1- (2,4,6-trichlorophenyl) -3-benzamido-5-pyrazolone, 6-hydroxy-4-methyl-3-cyano-1- (2-ethylhexyl) -2- Pyridone, 2,4-bis- (benzoylacetamido) toluene, 1,3-bis- (pivaloylacetamidomethyl) benzene, benzoylacetonitrile, thenoylacetonitrile, acetoacetanilide, benzoylacetanilide, pivaloylacetanilide, 2-chloro -5- (Nn-butylsulfamoyl) -1-pivaloylacetamidobenzene, 1- (2-ethylhexyloxypropyl) -3-cyano-4-methyl-6-hydroxy-1,2-dihydropyridine 2-one, 1- (dodecyloxypropyl) -3-acetyl- - methyl-6-hydroxy-1,2-dihydropyridin-2-one, 1- (4-n- octyloxyphenyl) -3-tert-butyl-5-aminopyrazole and the like.
[0087]
For details of the coupler compound, JP-A-4-201483, JP-A-7-223367, JP-A-7-223368, JP-A-7-323660, JP-A-5-278608, JP-A-5-297024, It is described in publications such as Kaihei 6-18669, JP-A-6-18670, and JP-A-7-316280. Japanese Patent Application No. 8-027095, Japanese Patent Application No. 8-027096, Japanese Patent Application No. 8-030799, Japanese Patent Application No. 8-12610, Japanese Patent Application No. 8-132394, Japanese Patent Application No. 8-127094, Reference can also be made to those described in Japanese Patent Application No. 8-358755, Japanese Patent Application No. 8-358756, Japanese Patent Application No. 9-069990, and the like.
[0088]
As content of the said coupler compound, 0.5-20 mass parts is preferable with respect to 1 mass part of diazonium salt compounds, and 1-10 mass parts is more preferable. When the content of the coupler compound is within the above range, it is more effective in terms of color developability, and the coating suitability is not deteriorated.
[0089]
The coupler compound can be used by adding a water-soluble polymer together with other components and solid-dispersing it with a sand mill or the like, but can also be emulsified with an appropriate emulsification aid and used as an emulsion. The method for solid dispersion or emulsification is not particularly limited, and can be appropriately selected from known methods. Details of the method are described in JP-A-59-190886, JP-A-2-141279, and JP-A-7-17145.
[0090]
For the purpose of accelerating the coupling reaction, it is preferable to use an organic base such as a tertiary amine, piperidine, piperazine, amidine, formamidine, pyridine, guanidine, or morpholine. Regarding organic bases, JP-A 57-123086, JP-A 60-49991, JP-A 60-94381, Japanese Patent Application No. 7-228731, Japanese Patent Application No. 7-235157, Japanese Patent Application No. 7- 235158 and the like. Although the usage-amount of an organic base is not specifically limited, 1-30 mol is preferable with respect to 1 mol of diazonium salt compounds.
[0091]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. In the examples, “%” is based on mass unless otherwise specified.
[0092]
Example 1
-Sample preparation-
A triacetyl cellulose support having a thickness of 130 μm was spin-coated with an ethyl acetate solution of the following compound (1) [component A] so that the layer thickness after drying was about 3 μm, and then dried. As a (first isolation layer), a dimethyl sulfoxide (DMSO) solution of nylon 66 was applied so that the layer thickness after drying was about 10 to 15 μm and dried. Thereafter, further vinylidene chloride (moisture permeability of 0.1% to 0.3 g / m at 0% RH / 90% RH) as the upper layer of the first isolation layer.²A dimethylformamide (DMF) solution of 24 hr · mm [25 ° C .; weight method) was spin-coated so that the layer thickness after drying was about 10 to 15 μm, and dried to form a second isolation layer. Furthermore, an emulsion of the following compound (2) [Component B] prepared separately on the second isolation layer and containing polyvinyl alcohol as a binder (solid content concentration 30%, concentration of the compound (2) with respect to the solid content is 50%) was applied so that the layer thickness after drying was 3 μm and dried. As described above, Sample 1 composed of the support / component A-containing layer / first separating layer / second separating layer / component B-containing layer was obtained. The isolation layer of Sample 1 is configured in a two-layer structure of a first isolation layer and a second isolation layer.
[0093]
[Chemical 3]

[0094]
-Evaluation-
Sample 1 obtained as described above was allowed to stand individually overnight under the environmental conditions of 23 ° C./20% RH and 23 ° C./80% RH, and each was then subjected to a static color tester from the surface of the component B-containing layer. When heated for 10 seconds, a cyan color corresponding to the applied temperature was obtained. The density of this cyan portion is measured using X-rite (manufactured by X-rite), and the difference between the temperatures at which a density corresponding to 50% of the maximum density is obtained (temperature at 80% −temperature at 20%). ) Was calculated. The calculated results are shown in Table 1 below.
[0095]
(Comparative Example 1)
Support / component A-containing layer / first separation layer / component in the same manner as in Example 1, except that the tetrahydrofuran (THF) solution of vinylidene chloride in Example 1 was not applied and the second separation layer was not provided. While obtaining the sample 2 comprised by the B content layer, the same evaluation was performed.
[0096]
(Comparative Example 2)
In Example 1, a solution of vinylidene chloride in tetrahydrofuran (THF) was added to polyvinyl alcohol (moisture permeability of 366 g / m at 0% RH / 90% RH).²24 hr · mm (weight method)) Except that the solution was replaced with an aqueous solution, a support / component A-containing layer / first separating layer / second separating layer / component B-containing layer was formed in the same manner as in Example 1. Sample 3 was obtained and the same evaluation was performed.
[0097]
[Table 1]

[0098]
As shown in Table 1 above, the moisture permeability is further 20 g / m adjacent to the first isolation layer protecting component A.²In an example in which a second isolation layer of 24 hr · mm or less is provided and a two-layer isolation layer is formed between components A and B, the humidity permeation performance of the first isolation layer protecting component A is dependent on humidity. It was possible to suppress color variation caused by humidity. On the other hand, the comparative example 1 which provided the single-layer isolation layer without providing the 2nd isolation layer, and the water vapor transmission rate of the polymer component which comprises a 2nd isolation layer are 20 g / m.²In Comparative Example 2 exceeding 24 hr · mm, the material permeation performance (the amount of heat required to obtain the same concentration) in the isolation layer was increased due to the humidity difference, resulting in large color variation.
[0099]
【The invention's effect】
According to the present invention, it is possible to provide a heat-sensitive recording material capable of stably forming an image without being affected by humidity fluctuations in the use environment.

Claims (4)

A heat sensitive material comprising a component A, a component B that develops the color of the component A, and an isolation layer that isolates the component A and the component B, and reacting the component B that has passed through the isolation layer with the component A to form a pigment component Recording material,
The isolation layer is constituted by a multilayer structure of at least two layers composed of different polymer components, and the permeability of the polymer component constituting the layer not contacting the component A of the isolation layer at 0% RH / 90% RH. A thermosensitive recording material having a humidity of 20 g / m ² · 24 hr · mm or less. The heat-sensitive recording material according to claim 1, wherein the layer that does not contact the component A of the isolation layer is a layer that contacts the component B. The heat-sensitive recording material according to claim 2, wherein the isolation layer constitutes a capsule wall of a microcapsule enclosing the component A, and a layer not in contact with the component A forms the outermost layer of the capsule wall. The thermosensitive recording material according to any one of claims 1 to 3, wherein a polymer main component constituting at least one layer of the isolation layer excluding the layer in contact with the component B is a urethane / urea polymer.