JP4195781B2 - Master for lithographic printing plate - Google Patents

Description

【００６８】
Ｒ¹、Ｒ³、Ｒ⁵は水素、又はメチル基を、Ｒ²、Ｒ⁴、Ｒ⁶、Ｒ⁷はそれぞれ置換基を有していてもよい炭素数１〜１２のアルキレン基、シクロアルキレン基、アリーレン基、又はアラルキレン基を表し、Ｘは−Ｏ−又は−ＮＲ⁸−を表し、Ｙは単結合又は−ＣＯ−基を表す。Ｒ⁸は水素原子、置換基を有していてもよい炭素数１〜１２のアルキル基、シクロアルキル基、アリール基又はアラルキル基を表す。具体的にはＮ−（４−カルボキシフェニル）−メタクリルアミド、Ｎ−（２−カルボキシフェニル）−アクリルアミド、Ｎ−（４−クロロ−２−カルボキシフェニル）−メタクリルアミド、４−カルボキシフェニルエチルメタクリレート、４−カルボキシスチレン、２−カルボキシフェニロキシエチルアクリレート等が挙げられる。
【００６９】
上記のカルボキシ基を有するモノマー以外の高分子化合物に、熱によってアルカリ可溶性となる性質を付与するモノマーとしては、１分子中に、窒素原子上に少なくとも１つの水素原子が結合したスルホンアミド基と、重合可能な不飽和結合をそれぞれ１つ以上有する低分子化合物からなるモノマーが好ましい。その中でも、アクリロイル基、アリル基又はビニロキシ基と、無置換或いはモノ置換アミノスルホニル基又は置換スルホニルアミノ基とを有する低分子化合物からなるモノマーが好ましい。このような化合物としては、例えば、下記一般式（IV）〜（VIII）で示される化合物が挙げられる。
【００７０】
【化２】

【００７１】
式中、Ｘ¹、Ｘ²はそれぞれ−Ｏ−又は−ＮＲ¹⁷−を表す。Ｒ¹、Ｒ⁴はそれぞれ水素原子又は−ＣＨ₃を表す。Ｒ²、Ｒ⁵、Ｒ⁸、Ｒ¹¹、Ｒ¹⁵はそれぞれ置換基を有していてもよい炭素数１〜１２のアルキレン基、シクロアルキレン基、アリーレン基又はアラルキレン基を表す。Ｒ³、Ｒ¹⁷、Ｒ¹²は水素原子、置換基を有していてもよい炭素数１〜１２のアルキル基、シクロアルキル基、アリール基又はアラルキル基を表す。また、Ｒ⁶、Ｒ¹⁶は、置換基を有していてもよい炭素数１〜１２のアルキル基、シクロアルキル基、アリール基又はアラルキル基を表す。Ｒ⁷、Ｒ⁹、Ｒ¹³は、水素原子又は−ＣＨ₃を表す。Ｒ¹⁰、Ｒ¹⁴はそれぞれ単結合又は置換基を有していてもよい炭素数１〜１２のアルキレン基、シクロアルキレン基、アリーレン基又はアラルキレン基を表す。Ｙ¹、Ｙ²はそれぞれ単結合又は−ＣＯ−を表す。
具体的には、ｍ−アミノスルホニルフェニルメタクリレート、Ｎ−（ｐ−アミノスルホニルフェニル）メタクリルアミド、Ｎ−（ｐ−トルエンスルホニル）アクリルアミド等を好適に使用することができる。
【００７２】
また上記（IV）〜（VIII）以外の他のモノマーとしては、１分子中に、−ＣＯ−ＮＨ−ＳＯ₂−で表される活性イミノ基と、重合可能な不飽和結合をそれぞれ１つ以上有する低分子化合物からなるモノマーも好ましい。このような化合物としては、具体的には、Ｎ−（ｍ−アミノスルホニル）メタクリルアミド、Ｎ−（ｐ−アミノスルホニル）メタクリルアミド、Ｎ−（ｐ−トルエンスルホニル）アクリルアミド等を好適に使用することができる。また、フェノール性水酸基を有するアクリルアミド、メタクリルアミド、アクリル酸エステル、メタクリル酸エステル又はヒドロキシスチレンからなるモノマーも他のモノマーとして好ましく用いられる。このような化合物としては、具体的にはＮ−（４−ヒドロキシフェニル）アクリルアミド、Ｎ−（４−ヒドロキシフェニル）メタクリルアミド、ｏ−、ｍ−、ｐ−ヒドロキシフェニルアクリレート、ｏ−、ｍ−、ｐ−ヒドロキシスチレン等が挙げられる。
【００７３】
上記モノマーの共重合成分としては、例えば、下記（１）〜（１１）に挙げるモノマーを用いることができ、下記モノマーを２成分以上含んでもよい。
（１）例えば、２−ヒドロキシエチルアクリレート又は２−ヒドロキシエチルメタクリレート等の脂肪族水酸基を有するアクリル酸エステル類及びメタクリル酸エステル類。
（２）アクリル酸メチル、アクリル酸エチル、アクリル酸プロピル、アクリル酸ブチル、アクリル酸アミル、アクリル酸ヘキシル、アクリル酸オクチル、アクリル酸ベンジル、アクリル酸２−クロロエチル、グリシジルアクリレート、Ｎ−ジメチルアミノエチルアクリレート等のアルキルアクリレート。
（３）メタクリル酸メチル、メタクリル酸エチル、メタクリル酸プロピル、メタクリル酸ブチル、メタクリル酸アミル、メタクリル酸ヘキシル、メタクリル酸シクロヘキシル、メタクリル酸ベンジル、メタクリル酸−２−クロロエチル、グリシジルメタクリレート、Ｎ−ジメチルアミノエチルメタクリレート等のアルキルメタクリレート。
（４）アクリルアミド、メタクリルアミド、Ｎ−メチロールアクリルアミド、Ｎ−エチルアクリルアミド、Ｎ−ヘキシルメタクリルアミド、Ｎ−シクロヘキシルアクリルアミド、Ｎ−ヒドロキシエチルアクリルアミド、Ｎ−フェニルアクリルアミド、Ｎ−ニトロフェニルアクリルアミド、Ｎ−エチル−Ｎ−フェニルアクリルアミド等のアクリルアミドもしくはメタクリルアミド。
【００７４】
（５）エチルビニルエーテル、２−クロロエチルビニルエーテル、ヒドロキシエチルビニルエーテル、プロピルビニルエーテル、ブチルビニルエーテル、オクチルビニルエーテル、フェニルビニルエーテル等のビニルエーテル類。
（６）ビニルアセテート、ビニルクロロアセテート、ビニルブチレート、安息香酸ビニル等のビニルエステル類。
（７）スチレン、α−メチルスチレン、メチルスチレン、クロロメチルスチレン等のスチレン類。
（８）メチルビニルケトン、エチルビニルケトン、プロピルビニルケトン、フェニルビニルケトン等のビニルケトン類。
（９）エチレン、プロピレン、イソブチレン、ブタジエン、イソプレン等のオレフィン類。
（１０）Ｎ−ビニルピロリドン、Ｎ−ビニルカルバゾール、４−ビニルピリジン、アクリロニトリル、メタクリロニトリル等。
（１１）マレイミド、Ｎ−アクリロイルアクリルアミド、Ｎ−アセチルメタクリルアミド、Ｎ−プロピオニルメタクリルアミド、Ｎ−（ｐ−クロロベンゾイル）メタクリルアミド等の不飽和イミド。
【００７５】
これらの熱によってアルカリ可溶性となる高分子化合物の重量平均分子量は５００〜２００，０００、数平均分子量は２００〜６０，０００であることが好ましい。熱によってアルカリ可溶性となる高分子化合物は単独で又は２種類以上を組み合わせて使用してもよく、サーマルポジ型画像形成層全固形分中５〜９９重量％、好ましくは１０〜９５重量％、特に好ましくは２０〜９０重量％の添加量で用いられる。添加量が５重量％未満であると画像形成層の耐久性が悪化し、また、９９重量％を越えると感度、耐久性の両面で好ましくない。
サーマルポジ型画像形成層には、上記、熱によってアルカリ可溶性となる高分子化合物の他に、バインダーが好適に添加される。バインダーとしては、ウレタン樹脂が挙げられ、中でも、カルボキシ基或いはスルホンアミド基を有するウレタン樹脂が好ましい。即ち、本発明に好適に使用されるポリウレタン樹脂は、ジイソシアナート化合物と、Ｎ上に少なくとも１つのＨ原子が結合したスルホンアミド基を含有するジオール化合物との反応生成物を基本骨格とするポリウレタン樹脂である。
【００７６】
本発明で好適に使用されるジイソシアナート化合物としては、２，４−トリレンジイソシアナート、２，４−トリレンジイソシアナートの二量体、２，６−トリレンジイソシアナート、ｐ−キシリレンジイソシアナート、ｍ−キシリレンジイソシアナート、４，４’−ジフェニルメタンジイソシアナート、１，５−ナフチレンジイソシアナート、３，３’−ジメチルビフェニル−４，４’−ジイソシアナート等の芳香族ジイソシアナート化合物；ヘキサメチレンジイソシアナート、トリメチルヘキサメチレンジイソシアナート、リジンジイソシアナート、ダイマー酸ジイソシアナート等の如き脂肪酸ジイソシアナート化合物；イソホロンジイソシアナート、４，４’−メチレンビス（シクロヘキシルイソシアナート）、メチルシクロヘキサン−２，４（又は２，６）ジイソシアナート、１，３−（イソシアナートメチル）シクロヘキサン等の脂環族ジイソシアナート化合物；１，３−ブチレングリコール１モルとトリレンジイソシアナート２モルとの付加体等のジオールとジイソシアナートとの反応物であるジイソシアナート化合物等が挙げられる。
【００７７】
また、Ｎ上に少なくとも１つのＨ原子が結合したスルホンアミド基を含有するジオール化合物としては、ｐ−（１，１−ジヒドロキシメチルエチルカルボニルアミノ）ベンゼンスルホンアミド、ｐ−（１，１−ジヒドロキシメチルエチルカルボニルアミノ）ベンゼンスルホンアミドのＮ−エチル体、Ｎ−（ｍ−メチルスルホニルアミノフェニル）−２，２−ジヒドロキシメチルプロパンアミド、Ｎ−（ｐ−メチルスルホニルアミノフェニル）−２，２−ジヒドロキシメチルプロパンアミド、Ｎ−（ｍ−エチルスルホニルアミノフェニル）−２，２−ジヒドロキシメチルプロパンアミド、Ｎ−（ｐ−エチルスルホニルアミノフェニル）−２，２−ジヒドロキシメチルプロパンアミド、Ｎ−（２，２−（ジヒドロキシエチルアミノカルボニル）エチル）メタンスルホンアミド、Ｎ−（２，２−（ジヒドロキシエチルアミノカルボニル）エチルベンゼンスルホンアミド、Ｎ−（２，２−（ジヒドロキシエチルアミノカルボニル）エチル−ｐ−トルエンスルホンアミド等が挙げられる。
【００７８】
これらのスルホンアミド基を含有するジオール化合物は、単独で又は２種以上組み合わせて使用することができる。また更に、スルホンアミド基を有さず、イソシアナートと反応しない他の置換基を有していてもよいジオール化合物をスルホンアミド基を有するジオール化合物と併用することもできる。このようなジオール化合物としては、エチレングリコール、ジエチレングリコール、トリエチレングリコール、テトラエチレングリコール、プロピレングリコール、ジプロピレングリコール、ポリエチレングリコール、ポリプロピレングリコール、ネオペンチルグリコール、１，３−ブチレングリコール、１，６−ヘキサンジオール、２−ブチル−１，４−ジオール、２，２，４−トリメチル−ｌ，３−ペンタンジオール、１，４−ビス−β−ヒドロキシエトキシシクロヘキサン、シクロヘキサンジメタノール、トリシクロデカンジメタノール、水添ビスフェノールＡ、水添ビスフェノールＦ、ビスフェノールＡのエチレンオキサイド付加体、ビスフェノールＡのプロピレンオキサイド付加体、ビスフェノールＦのエチレンオキサイド付加体、ビスフェノールＦのプロピレンオキサイド付加体、水添ビスフェノールＡのエチレンオキサイド付加体、水添ビスフェノールＡのプロピレンオキサイド付加体、ヒドロキノンジヒドロキシエチルエーテル、ｐ−キシリレングリコール、ジヒドロキシエチルスルホン、ビス（２−ヒドロキシエチル）−２，４−トリレンジカルバメート、２，４−トリレン−ビス（２−ヒドロキシエチルカルバミド）、ビス（２−ヒドロキシエチル）−ｍ−キシリレンジカルバメート、ビス（２−ヒドロキシエチル）イソフタレート、３，５−ジヒドロキシ安息香酸、２，２−ビス（ヒドロキシメチル）プロピオン酸、２，２−ビス（２−ヒドロキシエチル）プロピオン酸、２，２−ビス（３−ヒドロキシプロピル）プロピオン酸、ビス（ヒドロキシメチル）酢酸、ビス（４−ヒドロキシフェニル）酢酸、４，４−ビス（４−ヒドロキシフェニル）ペンタン酸、酒石酸等が挙げられる。
【００７９】
本発明に使用可能なポリウレタン樹脂は上記ジイソシアナート化合物及びジオール化合物を非プロトン性溶媒中、それぞれの反応性に応じた活性の公知な触媒を添加し、加熱することにより合成される。使用するジイソシアナート及びジオール化合物のモル比は好ましくは０．８：１〜１．２：１、より好ましくは０．８５：１．１〜１．１：１であり、ポリマー末端にイソシアネート基が残存した場合、この末端をアルコール類又はアミン類等で処理することにより、最終的にイソシアナート基が残存しないポリウレタン樹脂が合成される。
本発明に使用可能なウレタン樹脂の重量平均分子量は２，０００以上が好ましく、より好ましくは５，０００〜３０万である。また、数平均分子量は１，０００以上が好ましく、より好ましくは２，０００〜２５万の範囲である。また多分散度（重量平均分子量／数平均分子量）は１以上が好ましく、より好ましくは１．１〜１０の範囲である。
また、本発明に使用可能なバインダー中には、未反応の単量体が含まれていてもよい。この場合、単量体のバインダー中に占める割合は１５重量％以下が望ましい。以上挙げたバインダーは単独でも用いることができるが、１種以上混合することも好ましい。中でもノボラック樹脂と他に挙げたバインダーを混合して用いることが好ましい。
【００８０】
本発明のサーマルポジ型画像形成層には、更に必要に応じて、種々の添加剤を添加することができる。例えばオニウム塩、ｏ−キノンジアジド化合物、芳香族スルホン化合物、芳香族スルホン酸エステル化合物等の熱分解性であり、分解しない状態では、熱によってアルカリ可溶性となる高分子化合物の溶解性を実質的に低下させる物質を併用することは、画像部の現像液への溶解阻止性の向上を図る点では、好ましい。オニウム塩としてはジアゾニウム塩、アンモニウム塩、ホスホニウム塩、ヨードニウム塩、スルホニウム塩、セレノニウム塩、アルソニウム塩等を挙げる事ができる。
【００８１】
本発明において用いられるオニウム塩として、好適なものとしては、例えば S. I. Schlesinger, Photogr. Sci. Eng., 18, 387(1974) 、T. S. Bal et al, Polymer, 21, 423(1980) 、特開平５−１５８２３０号公報に記載のジアゾニウム塩、米国特許第4,069,055 号、同4,069,056 号、特開平3-140140号公報に記載のアンモニウム塩、D. C. Necker et al, Macromolecules, 17, 2468(1984)、C. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988)、米国特許第4,069,055号、同4,069,056号に記載のホスホニウム塩、J. V.Crivello et al, Macromorecules, 10(6), 1307 (1977)、Chem. & Eng. News, Nov. 28, p31 (1988)、欧州特許第104,143号、米国特許第339,049号、同第410,201号、特開平2-150848号、特開平2-296514号に記載のヨードニウム塩、J. V.Crivello et al, Polymer J. 17, 73 (1985)、J. V. Crivello et al. J. Org.Chem., 43, 3055 (1978)、W. R. Watt et al, J. Polymer Sci., Polymer Chem.Ed., 22, 1789 (1984)、J. V. Crivello et al, Polymer Bull., 14, 279 (1985) 、J. V. Crivello et al, Macromorecules, 14(5) ，1141(1981)、J. V. Crivello et al, J. Polymer Sci., Polymer Chem. Ed., 17, 2877 (1979) 、欧州特許第370,693号、同233,567号、同297,443号、同297,442号、米国特許第4,933,377号、同3,902,114号、同410,201号、同339,049号、同4,760,013号、同4,734,444号、同2,833,827号、独国特許第2,904,626号、同3,604,580号、同3,604,581号に記載のスルホニウム塩、J. V. Crivello et al, Macromorecules, 10(6), 1307 (1977)、J. V. Crivello et al, J. Polymer Sci., Polymer Chem. Ed., 17, 1047 (1979) に記載のセレノニウム塩、C. S. Wen et al, Teh,Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988)に記載のアルソニウム塩等が挙げられる。
【００８２】
本発明において、ジアゾニウム塩が特に好ましい。また、特に好適なジアゾニウム塩としては特開平５−１５８２３０号公報記載のものが挙げられる。
好適なキノンジアジド類としては、ｏ−キノンジアジド化合物を挙げることができる。本発明に用いられるｏ−キノンジアジド化合物は、少なくとも１個のｏ−キノンジアジド基を有する化合物で、熱分解によりアルカリ可溶性を増すものであり、種々の構造の化合物を用いることができる。つまり、ｏ−キノンジアジドは熱分解によりバインダーの溶解抑制能を失うことと、ｏ−キノンジアジド自身がアルカリ可溶性の物質に変化することの両方の効果により感材系の溶解性を助ける。本発明に用いられるｏ−キノンジアジド化合物としては、例えば、Ｊ．コーサー著「ライト−センシティブ・システムズ」（John Wiley & Sons. Inc.)第３３９〜３５２頁に記載の化合物が使用できるが、特に種々の芳香族ポリヒドロキシ化合物あるいは芳香族アミノ化合物と反応させたｏ−キノンジアジドのスルホン酸エステルまたはスルホン酸アミドが好適である。また、特公昭43−28403号公報に記載されているようなベンゾキノン（１，２）−ジアジドスルホン酸クロライドまたはナフトキノン−（１，２）−ジアジド−５−スルホン酸クロライドとピロガロール−アセトン樹脂とのエステル、米国特許第3,046,120号および同第3,188,210号に記載されているベンゾキノン−（１，２）−ジアジドスルホン酸クロライドまたはナフトキノン−（１，２）−ジアジド−５−スルホン酸クロライドとフェノール−ホルムアルデヒド樹脂とのエステルも好適に使用される。
【００８３】
さらにナフトキノン−（１，２）−ジアジド−４−スルホン酸クロライドとフェノールホルムアルデヒド樹脂あるいはクレゾール−ホルムアルデヒド樹脂とのエステル、ナフトキノン−（１，２）−ジアジド−４−スルホン酸クロライドとピロガロール−アセトン樹脂とのエステルも同様に好適に使用される。その他の有用なｏ−キノンジアジド化合物としては、数多くの特許に報告され知られている。例えば特開昭47−5303号、特開昭48−63802号、特開昭48−63803号、特開昭48−96575号、特開昭49−38701号、特開昭48−13354号、特公昭41−11222号、特公昭45−9610号、特公昭49−17481号、米国特許第2,797,213号、同第3,454,400号、同第3,544,323号、同第3,573,917号、同第3,674,495号、同第3,785,825号、英国特許第1,227,602号、同第1,251,345号、同第1,267,005号、同第1,329,888号、同第1,330,932号、ドイツ特許第854,890号などの各明細書中に記載されているものを挙げることができる。
ｏ−キノンジアジド化合物の添加量は、好ましくはサーマルポジ型画像形成層全固形分に対し、１〜５０重量％、更に好ましくは５〜３０重量％、特に好ましくは１０〜３０重量％の範囲である。これらの化合物は単一で使用できるが、数種の混合物として使用してもよい。
【００８４】
オニウム塩の対イオンとしては、四フッ化ホウ酸、六フッ化リン酸、トリイソプロピルナフタレンスルホン酸、５−ニトロ−ｏ−トルエンスルホン酸、５−スルホサリチル酸、２，５−ジメチルベンゼンスルホン酸、２，４，６−トリメチルベンゼンスルホン酸、２−ニトロベンゼンスルホン酸、３−クロロベンゼンスルホン酸、３−ブロモベンゼンスルホン酸、２−フルオロカプリルナフタレンスルホン酸、ドデシルベンゼンスルホン酸、１−ナフトール−５−スルホン酸、２−メトキシ−４−ヒドロキシ−５−ベンゾイル−ベンゼンスルホン酸及びパラトルエンスルホン酸等を挙げることができる。これらの中でも特に六フッ化リン酸、トリイソプロピルナフタレンスルホン酸や２，５−ジメチルベンゼンスルホン酸のごときアルキル芳香族スルホン酸が好適である。
ｏ−キノンジアジド化合物以外の添加剤の添加量は、サーマルポジ型画像形成層全固形分に対し、好ましくは１〜５０重量％、更に好ましくは５〜３０重量％、特に好ましくは１０〜３０重量％である。
【００８５】
更に感度を向上させる目的で、環状酸無水物類、フェノール類、有機酸類を併用することもできる。環状酸無水物としては、米国特許第４，１１５，１２８号明細書に記載されている無水フタル酸、テトラヒドロ無水フタル酸、ヘキサヒドロ無水フタル酸、３，６−エンドオキシ−Δ４−テトラヒドロ無水フタル酸、テトラクロル無水フタル酸、無水マレイン酸、クロル無水マレイン酸、α−フェニル無水マレイン酸、無水コハク酸、無水ピロメリット酸等が使用できる。フェノール類としては、ビスフェノールＡ、ｐ−ニトロフェノール、ｐ−エトキシフェノール、２，４，４′−トリヒドロキシベンゾフェノン、２，３，４−トリヒドロキシベンゾフェノン、４−ヒドロキシベンゾフェノン、４，４′，４″−トリヒドロキシトリフェニルメタン、４，４′，３″，４″−テトラヒドロキシ−３，５，３′，５′−テトラメチルトリフェニルメタン等が挙げられる。更に、有機酸類としては、特開昭６０−８８９４２号、特開平２−９６７５５号公報等に記載されている、スルホン酸類、スルフィン酸類、アルキル硫酸類、ホスホン酸類、リン酸エステル類及びカルボン酸類等があり、具体的には、ｐ−トルエンスルホン酸、ドデシルベンゼンスルホン酸、ｐ−トルエンスルフィン酸、エチル硫酸、フェニルホスホン酸、フェニルホスフィン酸、リン酸フェニル、リン酸ジフェニル、安息香酸、イソフタル酸、アジピン酸、ｐ−トルイル酸、３，４−ジメトキシ安息香酸、フタル酸、テレフタル酸、４−シクロヘキセン−１，２−ジカルボン酸、エルカ酸、ラウリン酸、ｎ−ウンデカン酸、アスコルビン酸等が挙げられる。
【００８６】
上記の環状酸無水物、フェノール類及び有機酸類の画像形成層中に占める割合は、０．０５〜２０重量％が好ましく、より好ましくは０．１〜１５重量％、最も好ましくは０．１〜１０重量％である。また、本発明における画像形成層中には、現像条件に対する処理の安定性を広げるため、特開昭６２−２５１７４０号公報や特開平３−２０８５１４号公報に記載されているような非イオン界面活性剤、特開昭５９−１２１０４４号公報、特開平４−１３１４９号公報に記載されているような両性界面活性剤を添加することができる。
【００８７】
非イオン界面活性剤の具体例としては、ソルビタントリステアレート、ソルビタンモノパルミテート、ソルビタントリオレート、ステアリン酸モノグリセリド、ポリオキシエチレンノニルフェニルエーテル等が挙げられる。両面活性剤の具体例としては、アルキルジ（アミノエチル）グリシン、アルキルポリアミノエチルグリシン塩酸塩、２−アルキル−Ｎ−カルボキシエチル−Ｎ−ヒドロキシエチルイミダゾリニウムベタインやＮ−テトラデシル−Ｎ，Ｎ−ベタイン型（例えば、商品名アモーゲンＫ、第一工業（株）製）等が挙げられる。上記非イオン界面活性剤及び両性界面活性剤は、サーマルポジ型画像形成層全固形分に対し、０．０５〜１５重量％が好ましく、より好ましくは０．１〜５重量％である。
【００８８】
［サーマルネガ型画像形成層］
タイプIIIのサーマルネガ型画像形成層は、少なくとも、下記一般式（IX）で表される構成単位を有するポリマー、熱架橋剤、酸発生剤及び後に詳述する光熱変換剤を含有する。
【００８９】
【化３】

【００９０】
一般式（IX）中、Ｒ¹は、水素原子又はメチル基を示す。Ｘ¹は、それ自体アルカリ可溶性を示すか、又は、アルカリ可溶性基を有する連結基を示す。ここで、アルカリ可溶性基とは、スルホン酸アミド、スルホン酸イミド又はカルボン酸イミドのような部分を含む基を指し、具体的には、−ＳＯ₂ＮＨ−、−ＮＨＳＯ₂−、−ＳＯ₂ＮＨＣＯ−、−ＣＯＮＨＳＯ₂−、−ＣＯＮＨＣＯ−等が挙げることができる。Ａｒ¹は、置換基を有していてもよい炭素数２０個以下の芳香族炭化水素基を示す。具体的には、ベンゼン環、ナフタレン環、アントラセン環、フェナントレン環等を挙げることができる。これらの芳香族炭化水素基のうち、入手性・経済性の観点から、ベンゼン環又はナフタレン環であることが好ましい。
【００９１】
また、これらの芳香族炭化水素基が有することができる好ましい置換基としては、炭素数２０以下の炭化水素基、ハロゲン原子、シアノ基、ニトロ基、カルボキシル基、カルバモイル基等を挙げることができる。Ｙ¹は、Ｎ−Ｒ³、酸素原子又は硫黄原子を示し、Ｒ²は、置換基を有していてもよい炭素数２０個以下の炭化水素基を示す。ここで、Ｒ³は、水素原子又は置換基を有していてもよい炭素数２０個以下の炭化水素基を示す。Ｒ²及びＲ³において用いることのできる好ましい置換基としては、ハロゲン原子、シアノ基、ニトロ基、カルボキシル基、カルバモイル基、炭素数２０以下のアルコキシル基、炭素数２０以下のペルフルオロアルキル基及び炭素数２０以下のヒドロキシアルキル基等を挙げることができる。また、ｎは１〜４の整数を示す。Ｌ¹は、単結合、エステル結合、カルボン酸アミド結合、スルホン酸アミド結合、エーテル結合、チオエーテル結合又はこれらの結合を含有していてもよい炭素数２０以下の炭化水素基を示す。Ｌ²は、単結合又は炭素数２０以下の炭化水素基を示すが、入手性・経済性の観点から、単結合であることが好ましい。
【００９２】
なお、Ｒ²とＡｒ¹及びＲ³とＡｒ¹、さらにＲ²とＲ³は、それぞれシクロヘキサン環等の環構造を形成していてもよい。本発明において好適に用いられる、一般式（IX）で表される構成単位を有するポリマーは、下記一般式（X）で表される構成単位を有するポリマーである。なお、一般式（X）中、一般式（IX）の符号と同じものについては同じ符号を付して説明を省略する。
【００９３】
【化４】

【００９４】
式中、Ｒ⁴及びＲ⁵は、同じでも異なっていてもよく、水素原子又は置換基を有していてもよい炭素数２０個以下の炭化水素基を示す。Ｒ⁴及びＲ⁵において用いることのできる好ましい置換基としては、ハロゲン原子、シアノ基、ニトロ基、カルボキシル基、カルバモイル基、炭素数２０以下のアルコキシル基、炭素数２０以下のペルフルオロアルキル基及び炭素数２０以下のヒドロキシアルキル基等を挙げることができる。なお、Ｒ⁴とＲ⁵は、縮環したベンゼン環やシクロヘキサン環等の環構造を形成していてもよい。一般式（X）で表される構成単位を有するポリマーは、対応する一般式（XI）で表されるモノマーを用い、従来公知の方法によりラジカル重合することにより得られる。
なお、一般式（XI）中、一般式（X）の符号と同じものについては同じ符号を付して説明を省略する。
【００９５】
【化５】

【００９６】
本発明において、好適に用いられる一般式（XI）で表されるモノマーの例を式（XI−１）〜（XI−１３）として以下に挙げる。なお、下記式中、Ｒ¹は水素原子又はメチル基を示し、Ｚ¹は酸素原子又はＮＨを示す。
【００９７】
【化６】

【００９８】
【化７】

【００９９】
【化８】

【０１００】
本発明において一般式（IX）で表される構成単位を有する好適なポリマーとしては、前記一般式（XI）で表されるモノマーの一種のみを用いた単独重合体や２種以上を用いた共重合体の双方を使用することができる。本発明で用い得る前記ポリマーは、一般式（XI）で表されるモノマーと、一般式（XI）で表されるモノマー以外の他の従来公知の重合性モノマーとの共重合体を使用することが塗布溶液に対する溶解性や塗膜の柔軟性の観点から、好ましい。
このような一般式（XI）で表されるモノマーと組み合わせて用いられる公知のモノマーとしては、例えば、メチルアクリレート、エチルアクリレート、プロピルアクリレート、ブチルアクリレート、２−エチルヘキシルアクリレート、シクロヘキシルアクリレート、２−ヒドロキシエチルアクリレート、ベンジルアクリレート等のアクリル酸エステル類、メチルメタクリレート、エチルメタクリレート、プロピルメタクリレート、ブチルメタクリレート、２−エチルヘキシルメタクリレート、シクロヘキシルメタクリレート、２−ヒドロキシエチルメタクリレート、ベンジルメタクリレート等のメタクリル酸エステル類、アクリロニトリル等が挙げられる。
【０１０１】
本発明の一般式（IX）で表される構成単位を有するポリマーは、その部分構造としてアルカリ可溶性を有する連結基（例えば、酸性基等）であるＸ¹を有しているため、アルカリ水に対する溶解性に優れているが、さらに補助的に他の酸性基を有するモノマーを用いた共重合体としても良い。用いられるモノマーとしては例えば、アクリル酸、メタクリル酸、イタコン酸、マレイン酸、Ｎ−（２−カルボキシエチル）アクリルアミド、Ｎ−（２−カルボキシエチル）メタクリルアミド、Ｎ−（カルボキシフェニル）アクリルアミド、Ｎ−（カルボキシフェニル）メタクリルアミド、カルボキシスチレン、マレイミド、Ｎ−（フェニルスルホニル）アクリルアミド、Ｎ−（フェニルスルホニル）メタクリルアミド、Ｎ−（トリルスルホニル）アクリルアミド、Ｎ−（トリルスルホニル）メタクリルアミド、Ｎ−（クロロフェニルスルホニル）アクリルアミド、Ｎ−（クロロフェニルスルホニル）メタクリルアミド、Ｎ−（スルファモイルフェニル）アクリルアミド、Ｎ−（スルファモイルフェニル）メタクリルアミド、Ｎ−（メチルスルファモイルフェニル）アクリルアミド、Ｎ−（メチルスルファモイルフェニル）メタクリルアミド、Ｎ−（フェニルスルファモイルフェニル）アクリルアミド、Ｎ−（フェニルスルファモイルフェニル）メタクリルアミド、Ｎ−（トリルスルファモイルフェニル）アクリルアミド、Ｎ−（トリルスルファモイルフェニル）メタクリルアミド、Ｎ−［（クロロフェニルスルファモイル）フェニル］アクリルアミド、Ｎ−［（クロロフェニルスルファモイル）フェニル］メタクリルアミド、Ｎ−（ヒドロキシフェニル）アクリルアミド、Ｎ−（ヒドロキシフェニル）メタクリルアミド、Ｎ−（ヒドロキシナフチル）アクリルアミド、Ｎ−（ヒドロキシナフチル）メタクリルアミド等が挙げられる。
【０１０２】
また、酸性基ではないが、ｐ−スチレンスルホン酸のナトリウム塩、２−アクリルアミド−２−メチルプロパンスルホン酸のアルカリ金属塩、テトラアルキルアンモニウム塩、３−スルホプロピルアクリレートのカリウム塩等の強酸の塩を含有するモノマーは、水に対する溶解性を向上でき、結果として画像形成層の水性現像液に対する現像性を向上できるので、共重合体の構成成分として好ましい。
これらを用いた共重合体中に含まれる一般式（IX）で表される構成単位の割合は、２０〜９５重量％であることが好ましく、さらに好ましくは３０〜９０重量％である。また、サーマルネガ型画像形成層に含有される一般式（IX）で表される構成単位を有するポリマーの重量平均分子量は、好ましくは５０００以上であり、さらに好ましくは１万〜３０万の範囲であり、数平均分子量は好ましくは１０００以上であり、さらに好ましくは２０００〜２５万の範囲である。多分散度（重量平均分子量／数平均分子量）は１以上が好ましく、さらに好ましくは１．１〜１０の範囲である。これらのポリマーは、ランダムポリマー、ブロックポリマー、グラフトポリマー等いずれでもよいが、ランダムポリマーであることが好ましい。
【０１０３】
一般式（IX）で表される構成単位を有するポリマーを合成する際に用いられる溶媒としては、例えば、テトラヒドロフラン、エチレンジクロリド、シクロヘキサノン、メチルエチルケトン、アセトン、メタノール、エタノール、エチレングリコールモノメチルエーテル、エチレングリコールモノエチルエーテル、２−メトキシエチルアセテート、ジエチレングリコールジメチルエーテル、１−メトキシ−２−プロパノール、１−メトキシ−２−プロピルアセテート、Ｎ，Ｎ−ジメチルホルムアミド、Ｎ，Ｎ−ジメチルアセトアミド、トルエン、酢酸エチル、乳酸メチル、乳酸エチル、ジメチルスルホキシド、水等が挙げられる。これらの溶媒は単独で又は２種以上混合して用いられる。合成する際に用いられるラジカル重合開始剤としては、アゾ系開始剤、過酸化物開始剤等公知の化合物が使用できる。一般式（IX）で表される構成単位を有するポリマーは単独で用いても混合して用いてもよく、サーマルネガ型画像形成層全固形分に対し２０〜９５重量％、好ましくは４０〜９０重量％の割合で画像形成材料中に添加される。添加量が２０重量％未満の場合は、画像形成した際、画像部の強度が不足する。また添加量が９５重量％を越える場合は、画像形成されない。
【０１０４】
サーマルネガ型画像形成層に用いられる熱架橋剤としては、分子内に２個以上のヒドロキシメチル基、アルコキシメチル基、エポキシ基又はビニルエーテル基を有する化合物を挙げることができる。好ましくはこれらの架橋性官能基が芳香環に直接結合した化合物である。具体的には、メチロールメラミン、レゾール樹脂、エポキシ化されたノボラック樹脂、尿素樹脂等が挙げられる。さらに、「架橋剤ハンドブック」（山下晋三、金子東助著、大成社（株））に記載されている化合物も好ましい。特に、分子内に２個以上のヒドロキシメチル基又はアルコキシメチル基を有するフェノール誘導体は画像形成した際の画像部の強度が良好であり好ましい。このようなフェノール誘導体として、具体的には、レゾール樹脂を挙げることができる。しかしながら、これらの熱架橋剤は当然ながら熱に対して不安定であり、画像形成材料を作成した後の保存時の安定性があまりよくない。これに対し、分子内に４〜８個のベンゼン核、少なくとも１個のフェノール性水酸基及び少なくとも２個の式（XII）で表される基を有するフェノール誘導体は保存時の安定性も良好であり、最も好適に用いられる。
【０１０５】
【化９】

【０１０６】
前記（XII）のＲ⁶は、水素原子、アルキル基又はアシル基を示し、アルキル基としては、メチル基、エチル基、ｎ−プロピル基、イソプロピル基、ｎ−ブチル基、イソブチル基、ｓｅｃ−ブチル基又はｔ−ブチル基のような炭素数１〜４のアルキル基が、アシル基としては、ホルミル基、アセチル基、ブチリル基、ベンゾイル基、シンナモイル基、バレリル基が好ましい。また、メトキシエチル基、メトキシプロピル基、ヒドロキシエチル基、ヒドロキシプロピル基等の炭素数１〜４の置換アルキル基を用いることができる。
サーマルネガ型画像形成層に使用可能なフェノール誘導体は、公知のフェノール化合物、例えば、特開平１−２８９９４６号公報、同３−１７９３５３号公報、同３−２００２５２号公報、同３−１２８９５９号公報、同３−２００２５４号公報、同５−１５８２３３号公報、同５−２２４４０９号公報に記載されているフェノール化合物と、ホルムアルデヒドとを強アルカリ性媒体中で約０〜８０℃、好ましくは１０〜６０℃の温度で１〜３０時間反応させることによりＲ⁶＝Ｈのものが得られる。
【０１０７】
その後、さらに酸性条件下、炭素数１〜４のアルコール、置換アルコール、酸ハライド又は酸無水物と、０〜８０℃で、１〜３０時間反応させることにより、Ｒ⁶＝アルキル、アシルのものが得られる。アルコール、置換アルコールと反応させる際の温度は、２０〜８０℃が好ましく、酸ハライド又は酸無水物と反応させる際の温度は、０〜３０℃が好ましい。本発明に使用可能なフェノール誘導体の具体例としては、下記一般式（XIII）〜（XX）で表わされる化合物が挙げられるがこれらに限定されるわけではない。これらのフェノール誘導体は、単独で用いてもよく、二種以上混合して用いてもよいが、その際の使用量は、サーマルネガ型画像形成層中、０．２〜６０重量％、好ましくは０．５〜２０重量％である。また、ベンゼン核が１〜３個で、フェノール性ヒドロキシル基と式（XII）で表わされる基を有する化合物は、着肉性、現像許容性の低下を招くため、サーマルネガ型画像形成層はこれらの化合物を実質的に含まないことが望ましい。より具体的には、サーマルネガ型画像形成層中５重量％以下であることが望ましく、更に好ましくは３重量％以下であり、最も好ましくは０重量％である。
【０１０８】
【化１０】

【０１０９】
【化１１】

【０１１０】
【化１２】

【０１１１】
【化１３】

【０１１２】
式中、Ｒ⁷〜Ｒ⁹、Ｒ¹⁴、Ｒ²²、Ｒ²³は水素原子、ハロゲン原子、アルキル基又はアルコキシ基を示し、Ｒ¹⁰、Ｒ¹⁸〜Ｒ²¹は水素原子又はアルキル基を示し、Ｒ¹¹〜Ｒ¹³は水素原子、ハロゲン原子又はアルキル基を示し、Ｒ¹⁵〜Ｒ¹⁷は、単結合、置換基を有してもよいアルキレン基、アルケニレン基、フェニレン基、ナフチレン基、カルボニル基、エーテル基、チオエーテル基、アミド結合又はそれら二種以上の組み合わせを示し、Ｙは一般式（XII）で表わされる基を示し、ａ、ｂ、ｃ、ｄ、ｘ、ｙは、０〜３の整数を示すが、ａ＋ｂ＋ｃ＋ｄ＋ｘ＋ｙは２〜１６の整数であり、ｋ、ｌ、ｍ、ｎは０〜３の整数を示すが、すべてが０になることはなく、ｅ、ｆ、ｇ、ｈ、ｐ、ｑ、ｒ、ｓ、ｔ、ｕは０〜３の整数を示し、ｚは０又は１を示す。
前記一般式（XIII）〜（XX）で表わされる化合物のより具体的な例としては、例えば下記構造のものが挙げられる。
【０１１３】
【化１４】

【０１１４】
【化１５】

【０１１５】
【化１６】

【０１１６】
【化１７】

【０１１７】
式中、Ｙ²〜Ｙ¹³は、水素原子又は式（XII）で表わされる基を示すが、各化合物中、少なくとも２個は式（XII）で表わされる基を有しており、好ましくは、すべてが式（XII）で表わされる基である。本発明において好適に用いられる他の熱架橋剤としては、アルデヒドやケトン化合物を挙げることができる。好ましくは、分子内に２個以上のアルデヒド又はケトンを有する化合物である。これらの熱架橋剤は単独で使用してもよく、また２種類以上を組み合わせて使用してもよい。本発明において、熱架橋剤はサーマルネガ型画像形成層固形分中、５〜７０重量％、好ましくは１０〜６５重量％の添加量で用いられる。熱架橋剤の添加量が５重量％未満であると画像形成した際の画像部の膜強度が悪化し、また、７０重量％を越えると保存時の安定性の点で好ましくない。
【０１１８】
さらに、サーマルネガ型画像形成層には酸発生剤が添加される。酸発生剤とは、光又は１００℃以上の加熱により分解し酸を発生する化合物であり、発生する酸としては、スルホン酸、塩酸等のｐＫａが２以下の強酸であることが好ましい。本発明において好適に用いられる酸発生剤としては、ヨードニウム塩、スルホニウム塩、ホスホニウム塩、ジアゾニウム塩等のオニウム塩が挙げられる。具体的には、ＵＳ４，７０８，９２５や特開平７−２０６２９号に記載されている化合物を挙げることができる。特に、スルホン酸イオンを対イオンとするヨードニウム塩、スルホニウム塩、ジアゾニウム塩が好ましい。
【０１１９】
ジアゾニウム塩としては、米国特許第３８６７１４７号記載のジアゾニウム化合物、米国特許第２６３２７０３号明細書記載のジアゾニウム化合物や特開平１−１０２４５６号及び特開平１−１０２４５７号の各公報に記載されているジアゾ樹脂も好ましい。また、ＵＳ５，１３５，８３８やＵＳ５，２００，５４４に記載されているベンジルスルホナート類も好ましい。さらに、特開平２−１０００５４号、特開平２−１０００５５号及び特開平９−１９７６７１号に記載されている活性スルホン酸エステルやジスルホニル化合物類も好ましい。他にも、特開平７−２７１０２９号に記載されている、ハロアルキル置換されたＳ−トリアジン類も好ましい。
これらの化合物は単独で使用してもよく、また２種以上を組み合わせて使用してもよい。これらの化合物は、サーマルネガ型画像形成層全固形分に対し０．０１〜５０重量％、好ましくは０．１〜２５重量％、より好ましくは０．５〜１５重量％の割合で添加される。添加量が０．０１重量％未満の場合は、画像が得られない。また添加量が５０重量％を越える場合は、印刷時非画像部に汚れを発生する。
【０１２０】
サーマルネガ型画像形成層には更に必要に応じて、種々の添加剤を添加することができる。例えば、ラジカル重合可能なエチレン性二重結合を分子内に２個以上有する多官能モノマーを添加することができる。このような化合物としては、エチレングリコールジ（メタ）アクリレート、ジエチレングリコールジ（メタ）アクリレート、ポリエチレングリコールジ（メタ）アクリレート、ヘキサンジオールジ（メタ）アクリレート、トリメチロールエタントリ（メタ）アクリレート、トリメチロールプロパントリ（メタ）アクリレート、ペンタエリスリトール及びジペンタエリスリトールのトリ−、テトラ−若しくはヘキサ（メタ）アクリレート等が挙げられる。これらの多官能モノマーの添加量は、サーマルネガ型画像形成層中３０重量％以下である。
【０１２１】
［機上現像サーマルネガ型画像形成層］
タイプIVの機上現像サーマルネガ型画像形成層は、熱反応性感応基を有する微粒子ポリマー又は熱反応性感応基を有する化合物を内包するマイクロカプセルを含有する。
【０１２２】
上記の熱反応性官能基としては、重合反応を行うエチレン性不飽和基（例えば、アクリロイル基、メタクリロイル基、ビニル基、アリル基など）、付加反応を行うイソシアナート基又はそのブロック体、その反応相手である活性水素原子を有する官能基（例えば、アミノ基、ヒドロキシル基、カルボキシル基など）、同じく付加反応を行うエポキシ基、その反応相手であるアミノ基、カルボキシル基又はヒドロキシル基、縮合反応を行うカルボキシル基とヒドロキシル基もしくはアミノ基、開環付加反応を行う酸無水物とアミノ基もしくはヒドロキシル基などを挙げることができる。しかし、化学結合が形成されるならば、どのような反応を行う官能基でも良い。
【０１２３】
該機上現像サーマルネガ型画像形成層に用いる、熱反応性官能基を有する微粒子ポリマーとしては、アクリロイル基、メタクリルロイル基、ビニル基、アリル基、エポキシ基、アミノ基、ヒドロキシル基、カルボキシル基、イソシアネート基、酸無水物およびそれらを保護した基を有するものを挙げることができる。これらの官能基のポリマー粒子への導入は、重合時に行ってもよいし、重合後に高分子反応を利用して行ってもよい。
【０１２４】
重合時に導入する場合は、これらの官能基を有するモノマーを乳化重合もしくは懸濁重合することが好ましい。
そのような官能基を有するモノマーの具体例として、アリルメタクリレート、アリルアクリレート、ビニルメタクリレート、ビニルアクリレート、グリシジルメタクリレート、グリシジルアクリレート、２−イソシアネートエチルメタクリレート、そのアルコールなどによるブロックイソシアナート、２−イソシアネートエチルアクリレート、そのアルコールなどによるブロックイソシアナート、２−アミノエチルメタクリレート、２−アミノエチルアクリレート、２−ヒドロキシエチルメタクリレート、２−ヒドロキシエチルアクリレート、アクリル酸、メタクリル酸、無水マレイン酸、２官能アクリレート、２官能メタクリレートなどを挙げることができるが、これらに限定されない。
【０１２５】
これらのモノマーと共重合可能な、熱反応性官能基をもたないモノマーとしては、例えば、スチレン、アルキルアクリレート、アルキルメタクリレート、アクリロニトリル、酢酸ビニルなどを挙げることができるが、熱反応性官能基をもたないモノマーであれば、これらに限定されない。
熱反応性官能基の導入を重合後に行う場合に用いる高分子反応としては、例えば、ＷＯ９６−３４３１６号公報に記載されている高分子反応を挙げることができる。
【０１２６】
上記の熱反応性官能基を有する微粒子ポリマーの中で、微粒子ポリマー同志が熱により合体するものが好ましく、その表面は親水性で、水に分散するものが特に好ましい。微粒子ポリマーのみを塗布し、凝固温度よりも低い温度で乾燥して作製した時の皮膜の接触角（空中水滴）が、凝固温度よりも高い温度で乾燥して作製した時の皮膜の接触角（空中水滴）よりも低くなることが好ましい。このように微粒子ポリマー表面を親水性にするには、ポリビニルアルコール、ポリエチレングリコールなどの親水性ポリマーまたはオリゴマー、または親水性低分子化合物を微粒子ポリマー表面に吸着させてやれば良いが、その方法はこれらに限定されるものではない。
【０１２７】
これらの熱反応性官能基を有する微粒子ポリマーの凝固温度は、７０℃以上が好ましいが、経時安定性を考えると１００℃以上がさらに好ましい。
上記の微粒子ポリマーの平均粒径は、０．０１〜２０μmが好ましいが、その中でも０．０５〜２．０μｍがより好ましく、特に０．１〜１．０μｍが好ましい。この範囲内で良好な解像度と経時安定性が得られる。
これらの反応性官能基を有する微粒子ポリマーの添加量は、機上現像サーマルネガ型画像形成層固形分の５０重量％以上が好ましく、６０重量％以上がさらに好ましい。
【０１２８】
該機上現像サーマルネガ型画像形成層に用いられるマイクロカプセルは、熱反応性官能基を有する化合物を内包している。この熱反応性官能基を有する化合物としては、重合性不飽和基、ヒドロキシル基、カルボキシル基、カルボキシレート基、酸無水物基、アミノ基、エポキシ基、イソシアナート基、及びイソシアナートブロック体を挙げることができる。
【０１２９】
重合性不飽和基を有する化合物としては、エチレン性不飽和結合、例えばアクリロイル基、メタクリロイル基、ビニル基、アリル基などを少なくとも１個、好ましくは２個以上有する化合物が好ましく、この様な化合物群は当該産業分野において広く知られるものであり、本発明においては、これらを特に限定なく用いることができる。これらは、化学的形態としては、モノマー、プレポリマー、すなわち２量体、３量体およびオリゴマー、またはそれらの混合物、及びそれらの共重合体である。
【０１３０】
例として、不飽和カルボン酸（例えば、アクリル酸、メタクリル酸、イタコン酸、クロトン酸、イソクロトン酸、マレイン酸など）、そのエステル、不飽和カルボン酸アミドが挙げられ、好ましくは、不飽和カルボン酸と脂肪族多価アルコールとのエステルおよび不飽和カルボン酸と脂肪族多価アミンとのアミドが挙げられる。
また、ヒドロキシル基、アミノ基、メルカプト基等の求核性置換基を有する不飽和カルボン酸エステルまたは不飽和カルボン酸アミドと単官能もしくは多官能のイソシアネートまたはエポキシドとの付加反応物、および単官能もしくは多官能のカルボン酸との脱水縮合反応物等も好適に使用される。
また、イソシアナート基やエポキシ基などの親電子性置換基を有する不飽和カルボン酸エステルまたはアミドと、単官能もしくは多官能のアルコール、アミンまたはチオールとの付加反応物、さらに、ハロゲン基やトシルオキシ基等の脱離性置換基を有する不飽和カルボン酸エステルまたはアミドと、単官能もしくは多官能アルコール、アミンまたはチオールとの置換反応物も好適である。
また、別の好適な例として、上記の不飽和カルボン酸を、不飽和ホスホン酸又はクロロメチルスチレンに置き換えた化合物を挙げることができる。
【０１３１】
不飽和カルボン酸と脂肪族多価アルコールとのエステルである重合性化合物の具体例としては、アクリル酸エステルとして、エチレングリコールジアクリレート、トリエチレングリコールジアクリレート、１，３−ブタンジオールジアクリレート、テトラメチレングリコールジアクリレート、プロピレングリコールジアクリレート、ネオペンチルグリコールジアクリレート、トリメチロールプロパンジアクリレート、トリメチロールプロパントリアクリレート、トリメチロールプロパントリス（アクリロイルオキシプロピル）エーテル、トリメチロールエタントリアクリレート、ヘキサンジオールジアクリレート、１，４−シクロヘキサンジオールジアクリレート、テトラエチレングリコールジアクリレート、ペンタエリスリトールジアクリレート、ペンタエリスリトールトリアクリレート、ペンタエリスリトールテトラアクリレート、ジペンタエリスリトールジアクリレート、ジペンタエリスリトールペンタアクリレート、ジペンタエリスリトールヘキサアクリレート、ソルビトールトリアクリレート、ソルビトールテトラアクリレート、ソルビトールペンタアクリレート、ソルビトールヘキサアクリレート、トリス（アクリロイルオキシエチル）イソシアヌレート、ポリエステルアクリレートオリゴマー等を挙げることができる。
【０１３２】
メタクリル酸エステルとしては、テトラメチレングリコールジメタクリレート、トリエチレングリコールジメタクリレート、ネオペンチルグリコールジメタクリレート、トリメチロールプロパントリメタクリレート、トリメチロールエタントリメタクリレート、エチレングリコールジメタクリレート、１，３−ブタンジオールジメタクリレート、ヘキサンジオールジメタクリレート、ペンタエリスリトールジメタクリレート、ペンタエリスリトールトリメタクリレート、ペンタエリスリトールテトラメタクリレート、ジペンタエリスリトールジメタクリレート、ジペンタエリスリトールヘキサメタクリレート、ソルビトールトリメタクリレート、ソルビトールテトラメタクリレート、ビス〔ｐ−（３−メタクリロイルオキシ−２−ヒドロキシプロポキシ）フェニル〕ジメチルメタン、ビス−〔ｐ−（メタクリロイルオキシエトキシ）フェニル〕ジメチルメタン等を挙げることができる。
【０１３３】
イタコン酸エステルとしては、エチレングリコールジイタコネート、プロピレングリコールジイタコネート、１，３−ブタンジオールジイタコネート、１，４−ブタンジオールジイタコネート、テトラメチレングリコールジイタコネート、ペンタエリスリトールジイタコネート、ソルビトールテトライタコネート等を挙げることができる。
【０１３４】
クロトン酸エステルとしては、エチレングリコールジクロトネート、テトラメチレングリコールジクロトネート、ペンタエリスリトールジクロトネート、ソルビトールテトラジクロトネート等を挙げることができる。
イソクロトン酸エステルとしては、エチレングリコールジイソクロトネート、ペンタエリスリトールジイソクロトネート、ソルビトールテトライソクロトネート等を挙げることができる。
マレイン酸エステルとしては、エチレングリコールジマレート、トリエチレングリコールジマレート、ペンタエリスリトールジマレート、ソルビトールテトラマレート等を挙げることができる。
【０１３５】
その他のエステルの例として、例えば、特公昭４６−２７９２６号、特公昭５１−４７３３４号、特開昭５７−１９６２３１号記載の脂肪族アルコール系エステル類や、特開昭５９−５２４０号、特開昭５９−５２４１号、特開平２−２２６１４９号記載の芳香族系骨格を有するもの、特開平１−１６５６１３号記載のアミノ基を含有するもの等を挙げることができる。
【０１３６】
また、脂肪族多価アミン化合物と不飽和カルボン酸とのアミドのモノマーの具体例としては、メチレンビス−アクリルアミド、メチレンビス−メタクリルアミド、１，６−ヘキサメチレンビス−アクリルアミド、１，６−ヘキサメチレンビス−メタクリルアミド、ジエチレントリアミントリスアクリルアミド、キシリレンビスアクリルアミド、キシリレンビスメタクリルアミド等を挙げることができる。
その他の好ましいアミド系モノマーの例としては、特公昭５４−２１７２６号記載のシクロへキシレン構造を有するものを挙げることができる。
【０１３７】
また、イソシアネートと水酸基の付加反応を用いて製造されるウレタン系付加重合性化合物も好適であり、そのような具体例としては、例えば、特公昭４８−４１７０８号公報中に記載されている１分子に２個以上のイソシアネート基を有するポリイソシアネート化合物に、下記式（II）で示される水酸基を有する不飽和モノマーを付加させた１分子中に２個以上の重合性不飽和基を含有するウレタン化合物等が挙げられる。
【０１３８】
一般式（II)
ＣＨ₂＝Ｃ（Ｒ¹）ＣＯＯＣＨ₂ＣＨ（Ｒ²）ＯＨ
（ただし、Ｒ¹およびＲ²は、それぞれＨまたはＣＨ₃を示す。）
【０１３９】
また、特開昭５１−３７１９３号、特公平２−３２２９３号、特公平２−１６７６５号に記載されているようなウレタンアクリレートや、特公昭５８−４９８６０号、特公昭５６−１７６５４号、特公昭６２−３９４１７号、特公昭６２−３９４１８号記載のエチレンオキサイド系骨格を有するウレタン化合物も好適なものとして挙げることができる。
さらに、特開昭６３−２７７６５３号、特開昭６３−２６０９０９号、特開平１−１０５２３８号に記載される、分子内にアミノ構造やスルフィド構造を有するラジカル重合性化合物を好適なものとして挙げることができる。
【０１４０】
その他の好適なものの例としては、特開昭４８−６４１８３号公報、特公昭４９−４３１９１号公報、同５２−３０４９０号公報の各公報に記載されているようなポリエステルアクリレート類、エポキシ樹脂と（メタ）アクリル酸を反応させたエポキシアクリレート類等の多官能のアクリレートやメタクリレートを挙げることができる。また、特公昭４６−４３９４６号公報、特公平１−４０３３７号公報、同１−４０３３６号公報記載の特定の不飽和化合物や、特開平２−２５４９３号公報に記載のビニルホスホン酸系化合物等も好適なものとして挙げることができる。また、ある場合には、特開昭６１−２２０４８号公報記載のペルフルオロアルキル基を含有する化合物も好適に使用される。さらに日本接着協会誌、２０巻７号、３００〜３０８ページ（１９８４年）に光硬化性モノマーおよびオリゴマーとして紹介されているものも好適に使用することができる。
【０１４１】
好適なエポキシ化合物としては、グリセリンポリグリシジルエーテル、ポリエチレングリコールジグリシジルエーテル、ポリプロピレンジグリシジルエーテル、トリメチロールプロパンポリグリシジルエーテル、ソルビトールポリグリシジルエーテル、ビスフェノール類もしくはポリフェノール類又はそれらの水素添加物のポリグリシジルエーテルなどが挙げられる。
【０１４２】
好適なイソシアネート化合物としては、トリレンジイソシアネート、ジフェニルメタンジイソシアネート、ポリメチレンポリフェニルポリイソシアネート、キシリレンジイソシアネート、ナフタレンジイソシアネート、シクロヘキサンフェニレンジイソシアネート、イソホロンジイソシアネート、ヘキサメチレンジイソシアネート、シクロヘキシルジイソシアネート、又は、それらをアルコールもしくはアミンでブロックした化合物を挙げることができる。
好適なアミン化合物としては、エチレンジアミン、ジエチレントリアミン、トリエチレンテトラミン、ヘキサメチレンジアミン、プロピレンジアミン、ポリエチレンイミンなどが挙げられる。
【０１４３】
好適なヒドロキシル基を有する化合物としては、末端メチロール基を有する化合物、ペンタエリスリトールなどの多価アルコール、ビスフェノール・ポリフェノール類などを挙げることができる。
好ましカルボキシル基を有する化合物としては、ピロメリット酸、トリメリット酸、フタル酸などの芳香族多価カルボン酸、アジピン酸などの脂肪族多価カルボン酸などが挙げられる。
好適な酸無水物としては、ピロメリット酸無水物、ベンゾフェノンテトラカルボン酸無水物などが挙げられる。
【０１４４】
エチレン状不飽和化合物の共重合体の好適なものとして、アリルメタクリレートの共重合体を挙げることができる。例えば、アリルメタクリレート／メタクリル酸共重合体、アリルメタクリレート／エチルメタクリレート共重合体、アリルメタクリレート／ブチルメタクリレート共重合体などを挙げることができる。
【０１４５】
マイクロカプセル化する方法としては、公知の方法が適用できる。例えばマイクロカプセルの製造方法としては、米国特許２８００４５７号、同２８００４５８号にみられるコアセルベーションを利用した方法、英国特許９９０４４３号、米国特許３２８７１５４号、特公昭３８−１９５７４号、同４２−４４６号、同４２−７１１号にみられる界面重合法による方法、米国特許３４１８２５０号、同３６６０３０４号にみられるポリマーの析出による方法、米国特許３７９６６６９号に見られるイソシアネートポリオール壁材料を用いる方法、米国特許３９１４５１１号に見られるイソシアネート壁材料を用いる方法、米国特許４００１１４０号、同４０８７３７６号、同４０８９８０２号にみられる尿素―ホルムアルデヒド系もしくは尿素ホルムアルデヒド−レゾルシノール系壁形成材料を用いる方法、米国特許４０２５４４５号にみられるメラミン−ホルムアルデヒド樹脂、ヒドロキシセルロース等の壁材を用いる方法、特公昭３６−９１６３号、同５１−９０７９号にみられるモノマー重合によるｉｎ ｓｉｔｕ法、英国特許９３０４２２号米国特許３１１１４０７号にみられるスプレードライング法、英国特許９５２８０７号、同９６７０７４号にみられる電解分散冷却法などがあるが、これらに限定されるものではない。
【０１４６】
該機上現像サーマルネガ型画像形成層に用いられる好ましいマイクロカプセル壁は、３次元架橋を有し、溶剤によって膨潤する性質を有するものである。このような観点から、マイクロカプセルの壁材は、ポリウレア、ポリウレタン、ポリエステル、ポリカーボネート、ポリアミド、およびこれらの混合物が好ましく、特に、ポリウレアおよびポリウレタンが好ましい。マイクロカプセル壁に熱反応性官能基を有する化合物を導入しても良い。
【０１４７】
上記のマイクロカプセルの平均粒径は、０．０１〜２０μmが好ましいが、中でも０．０５〜２．０μｍがさらに好ましく、０．１０〜１．０μｍが特に好ましい。この範囲内で、良好な解像度と経時安定性が得られる。
このようなマイクロカプセルは、カプセル同志が熱により合体してもよいし、合体しなくとも良い。要は、マイクロカプセル内包物のうち、塗布時にカプセル表面もしくはマイクロカプセル外に滲み出したもの、又は、マイクロカプセル壁に浸入したものが、熱により化学反応を起こせば良い。添加された親水性樹脂、又は、添加された低分子化合物と反応してもよい。また２種類以上のマイクロカプセルに、それぞれ異なる官能基で互いに熱反応するような官能基をもたせることによって、マイクロカプセル同士を反応させてもよい。
従って、熱によってマイクロカプセル同志が、熱で溶融合体することは画像形成上好ましいことであるが、必須ではない。
【０１４８】
マイクロカプセルの機上現像サーマルネガ型画像形成層への添加量は、固形分換算で、好ましくは１０〜６０重量％、さらに好ましくは１５〜４０重量％である。この範囲内で、良好な機上現像性と同時に、良好な感度および耐刷性が得られる。
【０１４９】
マイクロカプセルを機上現像サーマルネガ型画像形成層に添加する場合、内包物が溶解し、かつ壁材が膨潤する溶剤をマイクロカプセル分散媒中に添加することができる。このような溶剤によって、内包された熱反応性官能基を有する化合物の、マイクロカプセル外への拡散が促進される。
このような溶剤としては、マイクロカプセル分散媒、マイクロカプセル壁の材質、壁厚および内包物に依存するが、多くの市販されている溶剤から容易に選択することができる。例えば架橋ポリウレア、ポリウレタン壁からなる水分散性マイクロカプセルの場合、アルコール類、エーテル類、アセタール類、エステル類、ケトン類、多価アルコール類、アミド類、アミン類、脂肪酸類等が好ましい。
【０１５０】
具体的化合物としては、メタノール、エタノール、第３ブタノール、n−プロパノール、テトラヒドロフラン、乳酸メチル、乳酸エチル、メチルエチルケトン、プロピレングリコールモノメチルエーテル、エチレングリコールジエチルエーテル、エチレングリコールモノメチルエーテル、γ−ブチルラクトン、Ｎ，Ｎ−ジメチルホルムアミド、Ｎ，Ｎ−ジメチルアセトアミドなどがあるが、これらに限られない。またこれらの溶剤を２種以上用いても良い。
【０１５１】
マイクロカプセル分散液には溶解しないが、前記溶剤を混合すれば溶解する溶剤も用いることができる。添加量は、素材の組み合わせにより決まるものであるが、通常、塗布液の５〜９５重量％が好ましく、より好ましい範囲は、１０〜９０重量％、特に好ましい範囲は１５〜８５重量％である。
【０１５２】
該機上現像サーマルネガ型画像形成層には、このように熱反応性基を有する微粒子ポリマー又はマイクロカプセルを用いるので、必要に応じてこれらの反応を開始又は促進する化合物を添加してもよい。反応を開始又は促進する化合物としては、熱によりラジカル又はカチオンを発生するような化合物を挙げることができ、例えば、ロフィンダイマー、トリハロメチル化合物、過酸化物、アゾ化合物、ジアゾニウム塩又はジフェニルヨードニウム塩などを含んだオニウム塩、アシルホスフィン、イミドスルホナートなどが挙げられる。
これらの化合物は、機上現像サーマルネガ型画像形成層固形分の１〜２０重量％の範囲で添加することができる。好ましくは３〜１０重量％の範囲である。この範囲内で、機上現像性を損なわず、良好な反応開始又は促進効果が得られる。
【０１５３】
該機上現像サーマルネガ型画像形成層には親水性樹脂を添加しても良い。親水性樹脂を添加することにより機上現像性が良好となるばかりか、機上現像サーマルネガ型画像形成層自体の皮膜強度も向上する。
親水性樹脂としては、例えばヒドロキシル、カルボキシル、ヒドロキシエチル、ヒドロキシプロピル、アミノ、アミノエチル、アミノプロピル、カルボキシメチルなどの親水基を有するものが好ましい。
【０１５４】
親水性樹脂の具体例として、アラビアゴム、カゼイン、ゼラチン、澱粉誘導体、カルボキシメチルセルロースおよびそのナトリウム塩、セルロースアセテート、アルギン酸ナトリウム、酢酸ビニル−マレイン酸コポリマー類、スチレン−マレイン酸コポリマー類、ポリアクリル酸類およびそれらの塩、ポリメタクリル酸類およびそれらの塩、ヒドロキシエチルメタクリレートのホモポリマーおよびコポリマー、ヒドロキシエチルアクリレートのホモポリマーおよびコポリマー、ヒドロキシプロピルメタクリレートのホモポリマーおよびコポリマー、ヒドロキシプロピルアクリレートのホモポリマーおよびコポリマー、ヒドロキシブチルメタクリレートのホモポリマーおよびコポリマー、ヒドロキシブチルアクリレートのホモポリマーおよびコポリマー、ポリエチレングリコール類、ヒドロキシプロピレンポリマー類、ポリビニルアルコール類、ならびに加水分解度が少なくとも６０重量％、好ましくは少なくとも８０重量％の加水分解ポリビニルアセテート、ポリビニルホルマール、ポリビニルブチラール、ポリビニルピロリドン、アクリルアミドのホモポリマーおよびコポリマー、メタクリルアミドのホモポリマーおよびポリマー、Ｎ−メチロールアクリルアミドのホモポリマーおよびコポリマー等を挙げることができる。
【０１５５】
親水性樹脂の機上現像サーマルネガ型画像形成層への添加量は、該層固形分の５〜４０重量％が好ましく、１０〜３０重量％がさらに好ましい。この範囲内で、良好な機上現像性と皮膜強度が得られる。
【０１５６】
以上詳述したサーマルポジ型画像形成層、サーマルネガ型画像形成層および機上現像サーマルネガ型画像形成層には、共通して、レーザー光などの光を熱に変換するための光熱変換剤及び必要に応じて露光による加熱後直ちに可視像を得るための焼き出し剤、画像着色剤としての染料や顔料または画像形成層に柔軟性等を付与するための可塑剤などが添加される。
【０１５７】
本発明において、光熱変換剤としては種々の顔料もしくは染料を用いる事ができる。顔料としては、市販の顔料およびカラーインデックス（Ｃ．Ｉ．）便覧、「最新顔料便覧」（日本顔料技術協会編、１９７７年刊）、「最新顔料応用技術」（ＣＭＣ出版、１９８６年刊）、「印刷インキ技術」ＣＭＣ出版、１９８４年刊）に記載されている顔料が利用できる。
顔料の種類としては、黒色顔料、黄色顔料、オレンジ色顔料、褐色顔料、赤色顔料、紫色顔料、青色顔料、緑色顔料、蛍光顔料、金属粉顔料、その他、ポリマー結合色素が挙げられる。具体的には、不溶性アゾ顔料、アゾレーキ顔料、縮合アゾ顔料、キレートアゾ顔料、フタロシアニン系顔料、アントラキノン系顔料、ペリレンおよびペリノン系顔料、チオインジゴ系顔料、キナクリドン系顔料、ジオキサジン系顔料、イソインドリノン系顔料、キノフタロン系顔料、染付けレーキ顔料、アジン顔料、ニトロソ顔料、ニトロ顔料、天然顔料、蛍光顔料、無機顔料、カーボンブラック等が使用できる。
【０１５８】
これら顔料は表面処理をせずに用いてもよく、表面処理をほどこして用いてもよい。表面処理の方法には樹脂やワックスを表面コートする方法、界面活性剤を付着させる方法、反応性物質（例えば、シランカップリング剤やエポキシ化合物、ポリイソシアネート等）を顔料表面に結合させる方法等が考えられる。上記の表面処理方法は、「金属石鹸の性質と応用」（幸書房）、「印刷インキ技術」（ＣＭＣ出版、１９８４年刊）および「最新顔料応用技術」（ＣＭＣ出版、１９８６年刊）に記載されている。
【０１５９】
顔料の粒径は０．０１μｍ〜１０μｍの範囲にあることが好ましく、０．０５μｍ〜１μｍの範囲にあることがさらに好ましく、特に０．１μｍ〜１μｍの範囲にあることが好ましい。顔料の粒径が０．０１μｍ未満のときは分散物の画像形成層塗布液中での安定性の点で好ましくなく、また、１０μｍを越えると画像形成層の均一性の点で好ましくない。顔料を分散する方法としては、インク製造やトナー製造等に用いられる公知の分散技術が使用できる。分散機としては、超音波分散器、サンドミル、アトライター、パールミル、スーパーミル、ボールミル、インペラー、デスパーザー、ＫＤミル、コロイドミル、ダイナトロン、３本ロールミル、加圧ニーダー等が挙げられる。詳細は、「最新顔料応用技術」（ＣＭＣ出版、１９８６年刊）に記載がある。
【０１６０】
染料としては、市販の染料および文献（例えば「染料便覧」有機合成化学協会編集、昭和４５年刊）に記載されている公知のものが利用できる。具体的には、アゾ染料、金属錯塩アゾ染料、ピラゾロンアゾ染料、アントラキノン染料、フタロシアニン染料、カルボニウム染料、キノンイミン染料、メチン染料、シアニン染料などの染料が挙げられる。本発明において、これらの顔料、もしくは染料のうち赤外光、もしくは近赤外光を吸収するものが、赤外光もしくは近赤外光を発光するレーザでの利用に適する点で特に好ましい。
【０１６１】
そのような赤外光もしくは近赤外光を吸収する顔料としては、カーボンブラックが好適に用いられる。また、赤外光もしくは近赤外光を吸収する染料としては、例えば特開昭５８−１２５２４６号、特開昭５９−８４３５６号、特開昭５９−２０２８２９号、特開昭６０−７８７８７号等に記載されているシアニン染料、特開昭５８−１７３６９６号、特開昭５８−１８１６９０号、特開昭５８−１９４５９５号等に記載されているメチン染料、特開昭５８−１１２７９３号、特開昭５８−２２４７９３号、特開昭５９−４８１８７号、特開昭５９−７３９９６号、特開昭６０−５２９４０号、特開昭６０−６３７４４号等に記載されているナフトキノン染料、特開昭５８−１１２７９２号等に記載されているスクワリリウム色素、英国特許４３４，８７５号記載のシアニン染料等を挙げることができる。
【０１６２】
また、染料として米国特許第５，１５６，９３８号記載の近赤外吸収増感剤も好適に用いられ、また、米国特許第３，８８１，９２４号記載の置換されたアリールベンゾ（チオ）ピリリウム塩、特開昭５７−１４２６４５号（米国特許第４，３２７，１６９号）記載のトリメチンチアピリリウム塩、特開昭５８−１８１０５１号、同５８−２２０１４３号、同５９−４１３６３号、同５９−８４２４８号、同５９−８４２４９号、同５９−１４６０６３号、同５９−１４６０６１号に記載されているピリリウム系化合物、特開昭５９−２１６１４６号記載のシアニン色素、米国特許第４，２８３，４７５号に記載のペンタメチンチオピリリウム塩等や特公平５−１３５１４号、同５−１９７０２号公報に開示されているピリリウム化合物、エポリン社製Ｅｐｏｌｉｇｈｔ III−１７８、Ｅｐｏｌｉｇｈｔ III−１３０、Ｅｐｏｌｉｇｈｔ III−１２５等は特に好ましく用いられる。
【０１６３】
また、染料として特に好ましい別の例として、米国特許第４，７５６，９９３号明細書中に式（I）、（II）として記載されている近赤外吸収染料を挙げることができる。これらの顔料もしくは染料は、画像形成層全固形分に対し０．０１〜５０重量％、好ましくは０．１〜１０重量％、染料の場合特に好ましくは０．５〜１０重量％、顔料の場合特に好ましくは３．１〜１０重量％の割合で画像形成層中に添加することができる。顔料もしくは染料の添加量が０．０１重量％未満であると感度が低くなり、また５０重量％を越えると画像形成層の均一性が失われ、画像形成層の耐久性が悪くなる。
【０１６４】
焼き出し剤としては、露光による加熱によって酸を放出する化合物（光酸放出剤）と塩を形成し得る有機染料の組合せを代表として挙げることができる。具体的には、特開昭５０−３６２０９号、同５３−８１２８号の各公報に記載されているｏ−ナフトキノンジアジド−４−スルホン酸ハロゲニドと塩形成性有機染料の組合せや、特開昭５３−３６２２３号、同５４−７４７２８号、同６０−３６２６号、同６１−１４３７４８号、同６１−１５１６４４号及び同６３−５８４４０号の各公報に記載されているトリハロメチル化合物と塩形成性有機染料の組合せを挙げることができる。かかるトリハロメチル化合物としては、オキサゾール系化合物とトリアジン系化合物とがあり、どちらも経時安定性に優れ、明瞭な焼き出し画像を与える。
【０１６５】
画像の着色剤としては、前述の塩形成性有機染料以外に他の染料を用いることができる。好適な染料としては、塩形成性有機染料の他に、油溶性染料と塩基性染料を挙げることができる。具体的にはオイルイエロー＃１０１、オイルイエロー＃１０３、オイルピンク＃３１２、オイルグリーンＢＧ、オイルブルーＢＯＳ、オイルブルー＃６０３、オイルブラックＢＹ、オイルブラックＢＳ、オイルブラックＴ−５０５（以上オリエント化学工業（株）製）、ビクトリアピュアブルー、クリスタルバイオレット（ＣＩ４２５５５）、メチルバイオレット（ＣＩ４２５３５）、エチルバイオレット、ローダミンＢ（ＣＩ１４５１７０Ｂ）、マラカイトグリーン（ＣＩ４２０００）、メチレンブルー（ＣＩ５２０１５）等を挙げることができる。また、特開昭６２−２９３２４７号公報に記載されている染料は画像の着色剤として特に好ましい。これらの染料は、画像形成層全固形分に対し、０．０１〜１０重量％、好ましくは０．１〜３重量％の割合で画像形成層中に添加することができる。
【０１６６】
可塑剤としては、ブチルフタリル、ポリエチレングリコール、クエン酸トリブチル、フタル酸ジエチル、フタル酸ジブチル、フタル酸ジヘキシル、フタル酸ジオクチル、リン酸トリクレジル、リン酸トリブチル、リン酸トリオクチル、オレイン酸テトラヒドロフルフリル、アクリル酸又はメタクリル酸のオリゴマー及びポリマー等が用いられる。
【０１６７】
上記した、有機物からなるアブレーションポジ型画像形成層、サーマルポジ型画像形成層およびサーマルネガ型画像形成層は、通常、各成分を溶媒に溶かして、親水性表面を有する金属層上に塗布することにより製造することができる。
ここで使用する溶媒としては、エチレンジクロライド、シクロヘキサノン、メチルエチルケトン、メタノール、エタノール、プロパノール、エチレングリコールモノメチルエーテル、１−メトキシ−２−プロパノール、２−メトキシエチルアセテート、１−メトキシ−２−プロピルアセテート、ジメトキシエタン、乳酸メチル、乳酸エチル、Ｎ，Ｎ−ジメチルアセトアミド、Ｎ，Ｎ−ジメチルホルムアミド、テトラメチルウレア、Ｎ−メチルピロリドン、ジメチルスルホキシド、スルホラン、γ−ブチルラクトン、トルエン等を挙げることができるがこれに限定されるものではない。
【０１６８】
これらの溶媒は単独で又は混合して使用される。溶媒中の上記成分（添加剤を含む全固形分）の濃度は、好ましくは１〜５０重量％である。また塗布、乾燥後に得られる塗布量（固形分）は、用途によって異なるが、平版印刷版用原版についていえば一般的に０．５〜５．０ｇ／ｍ²が好ましい。
なお、塗布液中には、塗布性を良化するための界面活性剤、例えば特開昭６２−１７０９５０号公報に記載されているようなフッ素系界面活性剤を添加することができる。添加量は、好ましくは画像形成層の０．０１〜１重量％、より好ましくは０．０５〜０．５重量％である。
塗布方法としては、種々の方法を用いることができるが、例えば、バーコーター塗布、回転塗布、スプレー塗布、カーテン塗布、ディップ塗布、エアーナイフ塗布、ブレード塗布、ロール塗布等を挙げることができる。
【０１６９】
［製版方法］
次に、平版印刷版用原版を用いた平版印刷版の製版方法について説明する。上記した感熱型画像形成層を有する平版印刷版用原版は、例えば、熱記録ヘッドなどにより直接画像様に感熱記録を施したり、波長７６０〜１２００ｎｍの赤外線を放射する固体レーザー又は半導体レーザー、あるいは赤外線灯を用いたり、あるいはキセノン放電灯などによる高照度の紫外線又は可視光線のフラッシュ露光を行うなどの方法で画像露光される。
画像の書き込みは、面露光方式、走査方式のいずれでもよい。前者の場合は、赤外線照射方式や、キセノン放電灯の高照度の短時間光を原版上に照射して光・熱変換によって熱を発生させる方式である。赤外線灯などの面露光光源を使用する場合には、その照度によっても好ましい露光量は変化するが、通常は、印刷用画像で変調する前の面露光強度が０．１〜１０Ｊ／ｃｍ²の範囲であることが好ましく、０．３〜１Ｊ／ｃｍ²の範囲であることがより好ましい。
【０１７０】
後者の場合には、赤外線成分を多く含むレーザー光源を使用して、レーザービームを画像で変調して原版上を走査する方式が行われる。レーザー光源の例として、半導体レーザー、ヘリウムネオンレーザー、ヘリウムカドミウムレーザー、ＹＡＧレーザーを挙げることができる。ピーク出力が１０００Ｗ、好ましくは２０００Ｗのレーザーを照射するのが好ましい。この場合の露光量は、印刷用画像で変調する前の面露光強度が０．１〜１０Ｊ／ｃｍ²の範囲であることが好ましく、０．３〜１Ｊ／ｃｍ²の範囲であることがより好ましい。
画像露光された平版印刷版用原版は、露光後に現像し、更に必要であればガム引きを行ったのち、印刷機に版を装着し印刷を行うこともできる。また、露光後ただちに（現像工程を経ずに）印刷機に版を装着し印刷を行うこともできる。この場合は、湿し水等により、加熱部あるいは露光部が膨潤し、印刷初期に膨潤部が除去され、平版印刷版が形成される。即ち、本発明の平版印刷版用原版を使用する製版方法では、特に現像処理を経ることなく平版印刷版を製版し得る。ここでいう現像とは、水或いは水を主成分とするｐＨ２以上の現像液により現像することを指す。
【０１７１】
現像を行う場合も、現像処理を行わない場合も、露光後に加熱処理を行うことが記録時の感度向上の観点から好ましい。加熱処理の条件は、８０〜１５０℃の範囲内で１０秒〜５分間行うことが好ましい。即ち、この加熱処理を施すことにより、レーザー照射時、記録に必要なレーザーエネルギーを減少させることができる。
このような処理によって得られた本発明の平版印刷版用原版は現像されるかあるいは現像工程を経ずにそのままオフセット印刷機等にかけられ、多数枚の印刷に用いられる。
【０１７２】
【実施例】
以下、実施例により、本発明を詳細に説明するが、本発明はこれらに限定されるものではない。
（実施例１〜６および比較例１〜６：サーマルポジ型画像形成層）
支持体の作成方法
金属基板として０．２４ｍｍの厚みのアルカリ脱脂処理済みのアルミニウム板を使用し、以下の処理を順に行った。
【０１７３】
１）機械的粗面化処理方法
０．９号ナイロンブラシにてスラリー状の研磨剤（平均粒径１５μｍ程度のパミス）を供給しながら、回転数１５０ｒｐｍで研磨を行った。
２）化学的溶解処理方法ｉ
苛性ソーダの濃度２０ｗｔ％一定とし、温度４０℃で処理時間はＲａが０．３μｍになるように調整した。その後、１０秒流水にて水洗後、硫酸濃度１２０ｇ／リットル、液温５０℃、１０秒間浸漬し、デスマット処理を行った。Ｒａの計測値は、０．３±０．０５μｍ（標準偏差）であった。
３）電解粗面化処理方法
特開平３−７９７９９号公報の電源波形を使い、硝酸濃度１２ｇ／リットル、アルミニウム濃度を６ｇ／リットルの濃度に設定し、液温６０℃として陽極側の電流密度をピット個数が１．２〜９１個／ｍｍ²の範囲になるように設定した。その後水洗した。ピット個数はＳＥＭ観察の結果７０±２０個／ｍｍ²であった。
【０１７４】
４）化学的溶解処理方法ii
苛性ソーダの濃度２０ｗｔ％一定とし、温度４０℃で処理時間は１．３ｇ／ｍ²になるように調整した。その後、１０秒流水にて水洗後、硫酸濃度１２０ｇ／リットル、液温５０℃、１０秒間浸漬し、デスマット処理をおこなった。
５）陽極酸化処理方法
特開平８−２６４１１８号公報の図４の装置を２台直列接続した装置で、下記表１に示す陽極酸化処理条件で、直流電源を用いて電気を供給し、所望の陽極酸化皮膜厚となるように時間を調整し、被膜を生成させ、水洗した。Ｒａの計測値は、０．３±０．０５μｍ（平均±標準偏差）であった。
６）陽極酸化皮膜厚の決定方法
所望の陽極酸化皮膜厚になるような処理時間の決定方法は、検量線法により行った。例えば、表１に示す各陽極酸化処理条件で処理時間を変えて検量線試料とした。検量線試料の一部を折り曲げて、折り曲げた際に発生したひび割れ部分の側面（通称破断面）を超高分解能型ＳＥＭ（日立Ｓ−９００）を使用し、観察し、陽極酸化皮膜厚を測定した。これにより処理時間と陽極酸化皮膜厚との関係を示す検量線を作成し、この検量線から所望の陽極酸化皮膜厚に相当する処理時間を決定した。
【０１７５】
７）陽極酸化皮膜のポアの表面口部径と内部最大径の測定方法
陽極酸化皮膜のポアの表面口部径は超高分解能型ＳＥＭ（日立Ｓ−９００）を使用した。１２Ｖという比較的低加速電圧で、導電性を付与する蒸着処理等を施す事無しに、表面を１５万倍の倍率で観察し、５０個のポアを無作為抽出して平均値を使用した。標準偏差誤差は±１０％以下であった。
陽極酸化皮膜のポアの内部最大径は、陽極酸化処理済みのアルミを折り曲げて、折り曲げた際に発生したひび割れ部分の側面（通称破断面）を超高分解能型ＳＥＭ（日立Ｓ−９００）を使用し、観察した。１２Ｖという比較的低加速電圧で、導電性を付与する蒸着処理等を施す事無しに、陽極酸化皮膜の破断面のポアの内部最大径部分を１５万倍の倍率で観察し、５０個のポアを無作為抽出して平均値を使用した。標準偏差誤差は±１０％以下であった。
【０１７６】
８）封孔処理方法
実施例１〜４及び比較例１においては、上記陽極酸化処理を施したアルミニウム板を熱水中に表１に記載の所定時間通過させることにより封孔処理を行った。実施例６及び比較例４は、９０〜１００℃の０．１ｗｔ％ＮａＦ／１０ｗｔ％ＮａＨ₂ＰＯ₄水溶液（封孔剤Ａ）中に表１に記載の所定時間通過させることにより封孔処理を行った。実施例５並びに比較例１、２、５及び６については封孔処理を行わなかった。
【０１７７】
９）下塗り層の形成方法
上記封孔処理後の基板（基板［Ａ］とする）に３号珪酸ソーダ（Ｎａ₂Ｏ：ＳｉＯ₂＝１：３）珪酸ナトリウム濃度１ｗｔ％の水溶液にて２０℃で１０秒間処理し、水洗し、基板［Ｂ］を作製した。珪酸ナトリウムの被覆量は市販の蛍光Ｘ線分析装置によって検量線法にて定量分析をおこなった結果、珪酸としては６ｍｇ／ｍ²、珪酸ナトリウムとしては８ｍｇ／ｍ²であった。検量線用試料は、Ｘ線照射面積全面に３号珪酸ソーダを適量水希釈して一定容量滴下して広げて乾燥し、作製した。さらに上記基板［Ｂ］をｐＨ３の硝酸水溶液にて２０℃にて１０秒間処理し、水洗して、基板［Ｃ］を作製した。上記基板［Ｃ］の表面に、下記に示した組成のＡ型下塗り剤を塗布し、８０℃で１５秒間乾燥した。乾燥後の被覆量は１５ｍｇ／ｍ²であった。
【０１７８】
［Ａ型下塗り剤］
下記化合物 ０．３ｇ
メタノール １００ ｇ
水 １ ｇ
【０１７９】
【化１８】

【０１８０】
１０）画像形成層の形成方法
次に、上記のごとく処理された基板上に、以下の感光液１を塗布量が１．０ｇ／ｍ²になるように塗布したのち、ＴＡＢＡＩ社製、ＰＥＲＦＥＣＴ ＯＶＥＮＰＨ２００にてＷｉｎｄ Ｃｏｎｔｒｏｌを７に設定して１４０℃で５０秒間乾燥し、平版印刷版用原版を得た。
【０１８１】
〔感光液１〕
ｍ，ｐ−クレゾールノボラック（ｍ／ｐ比＝６／４、 ０．４２７ｇ
重量平均分子量３５００，未反応クレゾール０．５重量％含有）
シロキサン構造含有アルカリ可溶性樹脂（Ｆ−１） ０．０４７ｇ
特開平１１−２８８０９３号公報記載の特定の共重合体１ ２．３７ｇ
シアニン染料Ａ（下記構造） ０．１５５ｇ
２−メトキシ−４−（Ｎ−フェニルアミノ）ベンゼン ０．０３ｇ
ジアゾニウム・ヘキサフルオロホスフェート
テトラヒドロ無水フタル酸 ０．１９ｇ
エチルバイオレットの対イオンを６−ヒドロキシ−β− ０．０５ｇ
ナフタレンスルホン酸にしたもの
フッ素系界面活性剤（メガファックＦ−１７６ＰＦ、 ０．０３５ｇ
大日本インキ化学工業（株）製）
フッ素系界面活性剤（メガファックＭＣＦ−３１２、 ０．０５ｇ
大日本インキ化学工業（株）製）
ｐ−トルエンスルホン酸 ０．００８ｇ
ビス−ｐ−ヒドロキシフェニルスルホン ０．０６３ｇ
ステアリル酸ｎ−ドデシル ０．０６ｇ
γ−ブチルラクトン １３ｇ
メチルエチルケトン ２４ｇ
１−メトキシ−２−プロパノール １１ｇ
【０１８２】
［シロキサン構造含有アルカリ可溶性樹脂（Ｆ−１）の合成］
クレゾールノボラック（ｍ／ｐ＝６０／４０、Ｍｗ＝５．２×１０³）１２０ｇをメタノール４００ｍｌに溶解し、ナトリウムメトキシド５．４ｇを加え、３０分間攪拌した。メタノールを減圧留去し、テトラヒドロフラン４００ｍｌを加え、溶媒を置換した。エポキシ型末端反応性シリコーンＭＣＲ−Ｅ１１（（株）チッソ製）１７ｇを加え、６時間、加熱、還流した。反応液を室温まで冷却し、水８０００ｍｌに注ぎ込み、分離物をろ取、水洗、乾燥することによりシロキサン構造含有アルカリ可溶性樹脂（Ｆ−１）１３２ｇを得た。
【０１８３】
【化１９】

【０１８４】
１１）レーザー照射条件
市販の露光機：クレオ社製のトレンドセッター３２４４を用いて露光を行った。露光条件は出力０．５Ｗ、波長８３０ｎｍ、ビーム径１７μｍ（１／ｅ²）、主走査速度５ｍ／Ｓに設定した。
１２）クリア感度評価方法
平版印刷版用原版の版面にレーザーの照射出力を変えて全面露光し、富士写真フイルム（株）製現像液ＤＴ−１（１：８で希釈したもの）及び富士写真フイルム（株）製フィニッシャーＦＰ２Ｗ（１：１で希釈したもの）を仕込んだ富士写真フイルム（株）製ＰＳプロセッサー９００Ｈを用い、液温３０℃、現像時間１２秒にて現像した。このときの現像液の電導度は４５ｍＳ／ｃｍであった。現像後の平版印刷版をマクベス濃度計（設定;青色）で濃度の変化を計測し、縦軸をマクベス濃度、横軸をレーザーの出力とした場合の相関図の変化点（画像形成層が完全に無くなって支持体の色になる点）をクリア感度と見做し感度評価を行った。なお、比較例２の感度を基準（１００ｍＪ／ｃｍ²）として、各実施例１〜６、比較例１および比較例３〜６の感度を求めた。
【０１８５】
１３）印刷評価方法
上記の様にしてレーザー照射により画像露光した平版印刷版用原版を、富士写真フイルム（株）製現像液ＤＴ−１（１：８で希釈したもの）及び富士写真フイルム（株）製フィニッシャーＦＰ２Ｗ（１：１で希釈したもの）を仕込んだ富士写真フイルム（株）製ＰＳプロセッサー９００Ｈを用い、液温３０℃、現像時間１２秒にて現像した。このときの現像液の電導度は４５ｍＳ／ｃｍであった。現像後、得られた平版印刷版を印刷機に装着して印刷を行った。印刷機としては、ハリス菊半単色機（ハリス（株）製）を用い、インキとしてＧｅｏｓ墨（大日本インキ化学工業（株）製）、湿し水として、湿し水ＥＵ−３（富士写真フィルム（株）製）を１：１００に水で希釈したもの９０ｖｏｌ％とイソプロパノール１０ｖｏｌ％の混合物をそれぞれ用いて、上質紙上に印刷を行った。
【０１８６】
１４）残色、残膜性能評価方法
残色は、現像後、非画像部に残存している染料の量を市販の分光光度計（測定波長８３０ｎｍ）にて、相対評価した。
残膜は現像後、非画像部に残存しているバインダーの量を市販の分光光度計（測定波長２８０ｎｍ）にて、相対評価した。
１５）汚れ性能評価方法
印刷開始から５００枚印刷後に、印刷機を一時停止させて、印刷機のブランケット部分のインキを日東電工製ＰＥＴテープにて写し取り、非画像部のインキによる汚れ具合を目視にて評価した。
１６）耐刷性能評価方法
上記汚れ性能が△以下になった時点を刷了と判定し、その時点での印刷枚数を刷了枚数とした。
【０１８７】
それぞれの結果を以下、表１にまとめる。
【０１８８】
【表１】

【０１８９】
残色／残膜：◎；検出されない、○；少し検出される、△；検出される、
×；かなり検出される、××；全面検出される
汚れ：◎；全く汚れない、○；少し汚れる、△；汚れる、×；かなり汚れる、
××；全面汚れる
耐刷（刷了枚数）：◎；３万枚以上、○；３万枚未満１万枚以上、
△；１万枚未満３千枚以上、×；３千枚未満１００枚越え、
××；１００枚以下
【０１９０】
（実施例７〜１２および比較例７〜１２：サーマルネガ型画像形成層）
封孔処理方法までは実施例１〜６および比較例１〜６に準じ、下記表２の通りとした。
画像形成層の形成方法
基板上に下記画像形成層塗布液（処方Ｂ）を塗布バーにて塗布し、１００℃オーブンで１分間、乾燥させた。塗布液の塗布前後の厚みをマイクロメータで１０点計測し平均した結果、サーマルネガ型画像形成層（処方Ｂ）膜厚は平均１．５μｍ、標準偏差０．８μｍであった。塗布液の塗布前後の重量変化と比重から算出した厚みは、１．７μｍであった。これを平版印刷版用原版とした。
【０１９１】
画像形成層塗布液（処方Ｂ）
・光または熱によって酸を発生する下記化合物 ０．２ｇ
・酸により架橋する下記架橋剤（フェノール誘導体） ０．７ｇ
・バインダー（丸善石油化学（株）製のポリビニルフェノール １．５ｇ
「マルカリンカーＭＳ−４Ｐ）
・赤外線吸収剤ＮＫ−３５０８（商品名） ０．１５ｇ
（日本感光色素研究所（株）製）
・その他添加剤
ビクトリアピュアブルーＢＯ（Ｃ．Ｉ．４４０４０） ０．０５ｇ
フッ素系界面活性剤（メガファックＦ−１７７、 ０．０６ｇ
大日本インキ化学工業（株）製）
・溶剤
メチルエチルケトン １５ｇ
１−メトキシ−２−プロパノール ５ｇ
メチルアルコール ７ｇ
【０１９２】
【化２０】

【０１９３】
レーザー照射条件及び現像条件
得られた平版印刷版用原版を各々、波長１０６４ｎｍの赤外線を発する固体レーザーの連続発振ＹＡＧレーザー（最大光出力０．７２４Ｗ）で露光した。走査速度１２０ｃｍ／ｓ、１／ｅ²ビーム直径：Ｄ＝３５μｍ（ビームプロファイルは良好なガウス分布であったのでガウス分布近似し、ピーク最大強度の１／ｅ²光出力の位置をビーム直径とした。）で露光した後、１４０℃に温度設定したオーブン内で４５秒間加熱処理した。その後、加熱処理されたサンプルを浸漬型現像槽を有する市販の自動現像機ＰＳ−９００ＮＰ（富士写真フイルム（株）製）を用いて現像処理を行った。このＰＳ−９００ＮＰの現像処理槽には、下記組成のアルカリ現像処理液（ｐＨ約１３）が２０リットル仕込まれ、現像処理液の温度は３０℃に保温してあった。
ＰＳ−９００ＮＰの第２浴目には、水道水を８リットル、第３浴目には、ＦＰ２Ｗ（富士写真フイルム（株）製）：水＝１：１で希釈したフィニッシングガム液を８リットル仕込んだ。
【０１９４】
アルカリ現像処理液の組成
・Ｄ−ソルビット ２．５重量％
・水酸化ナトリウム ０．８５重量％
・ジエチレントリアミンペンター（メチレンホスホン酸） ０．０５重量％
５Ｎａ塩
・水 ９６．６重量％
【０１９５】
クリア感度、印刷評価方法は、現像条件等を上記の通りにした以外は、実施例１〜６および比較例１〜６と同じ方法で行った。なお、クリア感度においては、比較例８の感度を基準（１００ｍＪ／ｃｍ²）として、各実施例７〜１２、比較例７および比較例９〜１２の感度を求めた。また、残色、残膜性能、汚れ性能、耐刷評価方法も実施例１〜６および比較例１〜６と同じ方法で行った。
【０１９６】
それぞれの結果は以下の表２のようになった。
【表２】

【０１９７】
残色／残膜：◎；検出されない、○；少し検出される、△；検出される、
×；かなり検出される、××；全面検出される
汚れ：◎；全く汚れない、○；少し汚れる、△；汚れる、×；かなり汚れる、
××；全面汚れる
耐刷（刷了枚数）：◎；３万枚以上、○；３万枚未満１万枚以上、
△；１万枚未満３千枚以上、×；３千枚未満１００枚越え、
××；１００枚以下
【０１９８】
（実施例１３〜１８および比較例１３〜１８：アブレーションポジ型画像形成層）
封孔処理方法までは実施例１〜６および比較例１〜６に準じ、下記表３の通りとした。
【０１９９】
画像形成層の形成方法
上記封孔処理を行って支持体上にアブーレーション型の画像形成層塗布液を塗布乾燥させた。即ち、下記画像形成層塗布液（処方Ｃ）を塗布バーにて塗布し、１２０℃オーブンで１分間、乾燥させた。画像形成層（処方Ｃ）の塗布前後の厚みをマイクロメータで１０点計測し平均した結果、画像形成層（処方Ｃ）膜厚は平均１μｍ±標準偏差０．８μｍであった。画像形成層の塗膜形成前後の重量変化と比重から算出した厚みは、１μｍであった。
画像形成層塗布液（処方Ｃ）
ベヘン酸：５ｍｇ、ＰＭＭＡ：４１ｍｇ（アルドリッチ、平均分子量９９６０００（ＧＰＣ））、Ｃｙａｂｓｏｒｂ ＩＲ−１６５（Ａｍｅｒｉｃａｎ Ｃｙｎａｍｉｄ）：８ｍｇを１３ｃｃクロロホルムに溶解し、画像形成層塗布液（処方Ｃ）を作成した。
【０２００】
レーザー露光条件
連続発振ＹＡＧレーザー（波長１，０６４μｍ）、レーザー光最大出力０．７２４Ｗ、走査速度１２０ｃｍ／ｓ、１／ｅ²ビーム直径３５μｍ（ビームプロファイルは良好なガウス分布であったのでガウス分布近似し、ピーク最大強度の１／ｅ²光出力の位置をビーム直径とした。）
クリア感度、印刷評価方法は、現像処理を行わない以外は、実施例１〜６および比較例１〜６と同じ方法でおこなった。なお、クリア感度においては、比較例１４の感度を基準（１００ｍＪ／ｃｍ²）として、各実施例１３〜１８、比較例１３および比較例１５〜１８の感度を求めた。また、残色、残膜性能、汚れ性能、耐刷評価方法も実施例１〜６および比較例１〜６と同じ方法で行った。
【０２０１】
それぞれの結果は以下の表３のようになった。
【０２０２】
【表３】

【０２０３】
残色／残膜：◎；検出されない、○；少し検出される、△；検出される、
×；かなり検出される、××；全面検出される
汚れ：◎；全く汚れない、○；少し汚れる、△；汚れる、×；かなり汚れる、
××；全面汚れる
耐刷（刷了枚数）：◎；３万枚以上、○；３万枚未満１万枚以上、
△；１万枚未満３千枚以上、×；３千枚未満１００枚越え、
××；１００枚以下
【０２０４】
（実施例１９〜２９および比較例１９〜２６：アブレーションポジ型画像形成層）
なお、実施例２１及び実施例２９はそれぞれ参考例２１及び参考例２９と読替えるものとする。
下記表４に記載の性状（表面口部平均ポア径、内部ポア最大径、表面口部皮膜厚さ、内部ポア皮膜厚さ、表面口部ポア密度、ポア空隙率）の陽極酸化皮膜を有する支持体上に、前記実施例１３〜１８と同様のアブレーションポジ型画像形成層を設け、平版印刷版用原版とした。
これらの平版印刷版用原版の機上現像性、耐キズ性、感度及び耐刷性を評価した。
耐刷性については前記実施例１〜１８と同様の方法、機上現像性、耐キズ性及び感度については下記の方法で評価した。評価結果は、下記表４に示す。
【０２０５】
＜機上現像性評価方法＞
印刷機：ハリス菊半単色機(ハリス（株）製)
インキ：Ｇｅｏｓ紅（大日本インキ化学工業（株）製）
印刷開始時から正常な印刷物が得られるまでの印刷枚数を調べた。
【０２０６】
○：１〜５０枚
○△：５１〜１００枚
△：１０１〜２００枚
×：２０１枚以上
【０２０７】
＜耐キズ試験＞
引っ掻き試験機：HEIDON Scratching Intensity TESTER HEIDON−18
ダイヤモンド針を使用、荷重を５０〜４００ｇまで変化させた時のキズ付き難さの総合評価によりレベルを評価した。
【０２０８】
○：総合評価耐キズ性きわめて良好
△：良好（問題ないレベル）
×：不可
【０２０９】
＜感度＝クリア感度の評価方法＞
平版印刷版用原版の版面にレーザーの照射出力を変えて全面露光し、印刷機（ハリス菊半単色機(ハリス（株）製)）に装着し、インクを用いずに印刷機の運転を５分間行った後、平版印刷版をマクベス濃度計（設定：青色）で濃度の変化を計測し、縦軸をマクベス濃度、横軸をレーザーの出力とした場合の相関図の変化点（画像形成層が完全に無くなって支持体の色になる点）をクリア感度と見做し感度評価を行った。なお、比較例２０の感度を基準（１００ｍＪ／ｃｍ²）として、各実施例１９〜２９、比較例１９および比較例２１〜２６の感度を求めた。
【０２１０】
【表４】

【０２１１】
【発明の効果】
本発明に係わる平版印刷版用原版は、金属支持体上に、表面の口部径が０〜３０ｎｍで内部の最大径が４０〜３００ｎｍのポアを有する陽極酸化皮膜を有することにより、感度、汚れ、耐刷性能を維持しながら、残色性能、残膜性能を良化することができた。
また、陽極酸化皮膜のポア径０〜３０ｎｍの表面口部部分の厚さを１０〜５００ｎｍ、ポア径４０〜３００ｎｍの内部最大径部分の厚さを１００〜２０００ｎｍ、さらには、陽極酸化皮膜の表面部分のポア密度を２５００個／μｍ²以下、陽極酸化皮膜の空隙率を２０〜７０％とすることにより、耐キズ性を向上させることができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an original plate for a lithographic printing plate, particularly capable of plate making by scanning exposure based on a digital signal, has good sensitivity, hardly causes a residual color phenomenon or a residual film phenomenon, and has excellent stain resistance and printing durability. Also relates to an excellent lithographic printing plate precursor.
[0002]
[Prior art]
In the field of lithographic printing plate precursors, a metal support is widely used. Among them, aluminum is known to produce an oxide film by flowing direct current electricity as an anode in an acidic solution, and it is possible to perform a process generally known as an alumite process, and it is also lightweight and inexpensive. There are advantages. When alumite treatment is applied to the aluminum surface, the alumina oxide film has higher acid resistance and hardness than metal aluminum, and a large number of pores called pores are regularly formed in the film structure. The BET method (gas adsorption method) It is known that there are advantages such as improved hydrophilicity and improved adhesion when forming a coating film, since the surface area due to is greatly increased.
[0003]
In the production of pores, conventionally, an appropriate electrolytic solution such as sulfuric acid was used to supply a direct current to the support side by a constant current method, and an anodized film was produced in the electrolytic solution. When the fracture surface of the pore of the anodic oxide film obtained by such a method is observed with an ultrahigh resolution SEM (S-900) or the like, the cross-sectional shape of the pore can be observed. In that case, a pipe-like shape in which the diameters of the surface mouth portion and the maximum diameter portion are substantially the same is usual.
The pores of such an anodized film cause a decrease in residual color that remains after development due to the dye that is a photosensitive layer component, and a decrease in residual film that also leaves a binder that is also a photosensitive layer component after development. There was sometimes. Therefore, a technique is known in which the pores are sealed by an appropriate sealing process as necessary so that the photosensitive layer components do not enter the pores.
[0004]
In recent years, images can be formed by exposure in the near-infrared to infrared region, and particularly by recording images using heat generated during light irradiation using a laser having a light-emitting region in the region. A so-called heat mode type CTP lithographic printing plate precursor capable of making a plate directly from digital data of a computer or the like has attracted attention.
This can be done by changing the irradiation laser light for drawing into heat using a photothermal conversion material, etc., and changing the solubility in the developer with the generated heat, or thermally decomposing the photosensitive layer or explosive expansion by rapid heating. It is to be removed (ablated). When aluminum is used as a support for these lithographic printing plate precursors for heat mode type CTP (hereinafter also simply referred to as heat mode sensitive material), the heat conductivity is high, and the heat is rapidly dissipated to the support side. The loss of heat generation occurred, which was one of the causes of sensitivity reduction. In other words, if the heat insulating property of the support surface can be improved and the heat radiation can be minimized, it is expected that the sensitivity will be increased accordingly.
[0005]
On the other hand, a method to increase sensitivity by using an organic material with low thermal conductivity such as PET as a support has also been tried, but it has lower hydrophilicity than metal materials, and absorbs moisture during printing to achieve dimensional accuracy. The current situation is that it cannot be used for advanced printing such as color printing and high-definition printing.
As a support for a heat mode sensitive material, there has been a problem of improving the heat insulation, which is the only drawback, while taking advantage of the advantages of various surface treatments of aluminum, hydrophilicity, dimensional accuracy stability and the like.
[0006]
As a means to improve the heat insulation of aluminum, by utilizing the property of low thermal conductivity of the anodized film itself, the thickness of the film is increased, or after forming the anodized film, it is immersed in an aqueous acid solution or an alkaline solution, There is a method of increasing the pore diameter and increasing the porosity. If the film thickness is increased, an extra amount of electricity is required, which increases the cost, and the remaining color tends to be noticeable because the pore becomes deeper by that amount. On the other hand, when the pore diameter is increased, the porosity in the anodized film on the surface of the support is improved and the heat insulation is improved, so that the heat generated by laser irradiation hardly escapes to the metal aluminum plate side. Since the heat generated as a result effectively acts in the photosensitive layer, the sensitivity becomes high. On the other hand, when the pore is enlarged, the photosensitive layer and the colored dye for laser beam absorption contained in the photosensitive layer enter into the pore and cause a residual color and a residual film. As a method of reducing the residual color, the surface of the anodized film is coated by performing sealing treatment such as hot water sealing treatment with a small amount of sealing agent mixed in, reducing the specific surface area, and at the same time, the photosensitive layer components inside the pore Since the color does not enter, the residual color performance is improved. However, as a result of performing the sealing treatment and covering the surface, there is a problem that when the pore density decreases, the photosensitive layer enters the inside of the pore, the striking effect is reduced, and the adhesion is reduced. Further, when the pores are enlarged, multiple pores are formed in a state where the pores are in contact with each other, and the strength of the anodized film is extremely reduced. As a result, there arises a problem that stains due to film peeling and printing durability deteriorate.
[0007]
[Problems to be solved by the invention]
The present invention overcomes the above-mentioned drawbacks of the prior art, can improve the residual color performance and the residual film performance while maintaining the sensitivity, and further provides a lithographic printing plate precursor excellent in stain resistance and printing durability. It is something to be offered.
[0008]
[Means for Solving the Problems]
  As a result of diligent efforts, the present inventors have determined that the pores of the anodized film on the metal support have a maximum mouth diameter of 0-30 nm and a maximum internal diameter.40It has been found that by adjusting the thickness to ˜300 nm, the remaining color performance, the remaining film performance, the stain resistance and the printing durability can be improved while maintaining the sensitivity, and the present invention has been achieved.
  That is, the present invention provides a metal support having a surface mouth diameter of 0 to 30 nm and a maximum internal diameter.40A lithographic printing plate precursor comprising an anodized film having a pore of ˜300 nm and an image forming layer containing a photothermal conversion agent on the anodized film.
[0009]
  In the lithographic printing plate precursor of the present invention, the average diameter of the mouth of the surface is 0 to 30 nm and the average diameter of the bottom is on the anodized film on the metal support.40By having a pore of ˜300 nm, the porosity of the anodized film is in an appropriate range, the heat insulation property of the anodized film is improved, and heat generated by laser irradiation does not escape to the metal support, resulting in Therefore, it is effective in the image forming layer, resulting in high sensitivity. Further, a residual color phenomenon in which a dye that is an image forming layer component enters and remains, and a residual film phenomenon in which a binder that is also an image forming layer component remains are less likely to occur. Further, since the multiple pores are formed in the state where the pores are in contact with each other and the strength of the anodized film is not extremely lowered, the stain due to the film peeling and the deterioration of the printing durability do not occur. That is, the stain resistance and printing durability are excellent.
[0010]
  Moreover, it is preferable that the lithographic printing plate precursor of the present invention is subjected to a sealing treatment on the surface mouth portion of the pore of the anodized film so that the average diameter of the surface mouth portion is reduced. In that case, as a result of covering the surface, the pore density is reduced and the image forming layer enters the inside of the pore, the striking effect is reduced, and the adhesion force is reduced. Therefore, anodization is performed for the purpose of compensating for the reduction in adhesion force. It is desirable to perform an electrolytic surface roughening treatment on the metal support before.
  Further, the thickness of the surface opening portion of the anodized film having a pore diameter of 0 to 30 nm is 10 to 500 nm, and the pore diameter is40The thickness of the inner maximum diameter portion of ˜300 nm is preferably 100 to 2,000 nm, and the pore density of the surface portion of the anodized film is 2500 / μm.²Preferably, the porosity of the anodized film is 20 to 70%.
[0011]
The lithographic printing plate precursor according to the invention may have a pore diameter of 0 to 30 nm on the surface of the pore of the anodized film, but is preferably 5 to 20 nm. If it exceeds 30 nm, the image forming layer and the sealing agent enter the pores, and the background stains, ink repellency, on-machine developability and the like deteriorate.
Moreover, the lithographic printing plate precursor according to the present invention may have a maximum inside diameter of 20 to 300 nm, preferably 40 to 200 nm, inside the pores of the anodized film. If it is less than 20 nm, the porosity is lowered, the sensitivity is lowered, and the printing durability is deteriorated. On the other hand, if it exceeds 200 nm, the strength of the anodized film itself is lowered and the printing durability is deteriorated.
[0012]
Moreover, although the thickness of the surface opening part of the pore diameter of 0-30 nm of an anodized film is preferable if it is 10-500 nm, 50-300 nm is more preferable. If it is less than 10 nm, scratch resistance may be lowered. On the other hand, if it exceeds 500 nm, the production cost (mainly power cost) is undesirably high although the effect on quality is small.
Moreover, although the thickness of the internal maximum diameter part of the pore diameter 20-300 nm of an anodized film is preferable if it is 100-2000 nm, 500-1500 nm is more preferable. If the thickness is less than 100 nm, the sensitivity is low and the printing durability may be deteriorated. On the other hand, if it exceeds 2000 nm, the production cost (mainly power cost) is increased although the quality effect is small.
[0013]
The pore density of the surface portion of the anodized film is 2500 / μm²The following is preferable, but 500 to 2000 / μm²Is more preferable. 2500 / μm²If it exceeds 1, scratch resistance may be reduced.
Furthermore, the porosity of the anodized film is preferably 20 to 70%, more preferably 30 to 50%. If it is less than 20%, the sensitivity may be lowered and printing durability may be lowered. On the other hand, if it exceeds 70%, scratch resistance may be deteriorated.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the lithographic printing plate precursor according to the invention will be described in more detail.
[Metal support]
Various metals can be used as the metal support used in the lithographic printing plate precursor according to the present invention. Among them, it is preferable to use aluminum, copper, stainless steel, plated steel plate, or the like. Most preferably, aluminum that is excellent in rust prevention, has high recyclability, has a low specific gravity, is excellent in handleability, and is inexpensive.
As the aluminum material provided for this purpose, JIS1050 material, JIS1100 material, JIS1070 material, Al-Mn alloy, Al-Mn-Mg alloy, Al-Zr alloy, Al-Mg-Si alloy, etc. are used. Has been.
[0015]
Regarding the JIS 1050 material, the technology developed by the present inventors is disclosed in the following patent publications. JP 59-153861, JP 61-51395, JP 62-146694, JP 60-215725, JP 60-215726, JP 60-215727, JP JP 60-216728, JP 61-272367, JP 58-11759, JP 58-42493, JP 58-212254, JP 62-148295, JP 4-4-1 JP-A-254545, JP-A-4-165541, JP-B-3-68939, JP-A-3-234594, JP-B-1-47545, and JP-A-62-140894. In addition, techniques disclosed in Japanese Patent Publication No. 1-35910 and Japanese Patent Publication No. 55-28874 are also known.
[0016]
Regarding the JIS 1070 material, the technology developed by the present inventors is disclosed in the following patent publications. JP-A-7-81264, JP-A-7-305133, JP-A-8-49034, JP-A-8-73974, JP-A-8-108659, and JP-A-8-92679.
Regarding the Al—Mg alloy, the technology developed by the present inventors is disclosed in the following patent publications. JP-B-62-5080, JP-B-63-60823, JP-B-3-61753, JP-A-60-20396, JP-A-60-203497, JP-B-3-11635, JP-A-61-274993 JP, Sho 62-23794, JP 63-47347, JP 63-47348, JP 63-47349, JP 64-1293, JP 63-135294, JP 63-87288, JP 4-73392, JP 7-100904, JP 62-149856, JP 4-73394, JP 62-181191, JP 5-76530. JP, 63-30294 and JP-B-6-37116. Also disclosed in JP-A-2-215599 and JP-A-61-201747.
[0017]
Regarding the Al—Mn alloy, the technology developed by the present inventors is disclosed in the following patent publications. JP-A-60-230951, JP-A-1-306288 and JP-A-2-293189. In addition, JP-B-54-42284, JP-B-4-19290, JP-B-4-19291, JP-B-4-19292, JP-A-61-35995, JP-A-64-51992, JP-A-4-19592, No. 226394, US Pat. Nos. 5,009,722 and 5,028,276, etc.
Regarding the Al—Mn—Mg alloy, the technology developed by the present inventors is disclosed in the following patent publications. JP-A-62-86143 and JP-A-3-222296. JP-B 63-60824, JP-A 60-63346, JP-A 60-63347, JP-A-1-293350, European Patent 223737, US Patent 4,818,300, British Patent It is also disclosed in each specification of No. 1,222,777.
[0018]
Regarding the Al—Zr alloy, the technology developed by the present inventors is disclosed in the following patent publications. Japanese Examined Patent Publication Nos. 63-15978 and 61-51395. Also disclosed in JP-A-63-143234 and JP-A-63-143235.
The Al—Mg—Si alloy is disclosed in British Patent 1,421,710.
[0019]
In general, in order to obtain an aluminum or aluminum alloy plate used for a lithographic printing plate support, first, the aluminum alloy molten metal having the above-described components and alloy component ratios is subjected to a cleaning treatment according to a conventional method and cast.
In the cleaning process, so-called rigid media filters such as flux processing, degassing using argon gas, chlorine gas, ceramic tube filters, ceramic foam filters, etc. are used to remove unnecessary gases such as hydrogen in the molten metal. In addition, a filter using an alumina flake, an alumina ball or the like as a filter medium, a filtering using a glass cloth filter or the like, or a process combining degassing and filtering is performed. These cleaning treatments are preferably performed in order to prevent defects caused by foreign matters such as non-metallic inclusions and oxides in the molten metal and defects caused by gas dissolved in the molten metal. Regarding filtering of the molten metal, JP-A-6-57432, JP-A-3-162530, JP-A-5-140659, JP-A-4-231425, JP-A-4-276031, JP-A-5-311261, JP-A-5-311261 6-136466, and the like. Further, the degassing of the molten metal is described in JP-A-5-51659, JP-A-5-49148, and the like. The present inventors have also disclosed a technique relating to degassing of molten metal in Japanese Patent Application Laid-Open No. 7-40017.
[0020]
As described above, casting is performed using the molten metal that has been subjected to the cleaning treatment. As for the casting method, there are a method using a solid mold typified by a DC casting method and a method using a driving mold typified by a continuous casting method. When the DC casting method is used, the cooling rate solidifies in the range of 0.5 to 30 ° C./second. When it is less than 0.5 ° C./second, a large number of coarse intermetallic compounds are formed. In the continuous casting method, a method using a cooling roll typified by the Hunter method and the 3C method, and a method using a cooling belt and a cooling block typified by the Husley method and the Al Swiss Caster II type are industrially performed. ing. When the continuous casting method is used, it solidifies at a cooling rate of 100 to 1000 ° C./second. In general, since the cooling rate is higher than that of the DC casting method, there is a feature that the solid solubility of the alloy component in the aluminum matrix can be increased. With respect to the continuous casting method, the present inventors have disclosed, for example, JP-A-3-79798, JP-A-5-201166, JP-A-5-156414, JP-A-6-262203, JP-A-6-122949, JP-A-6-122949. 210406, JP-A-6-26308, and the like. When DC casting is performed, an ingot having a thickness of 300 to 800 mm can be produced.
[0021]
The ingot is chamfered as necessary according to a conventional method to cut 1 to 30 mm, preferably 1 to 10 mm, of the surface layer.
Before and after that, soaking treatment is performed as necessary. When performing the soaking process, heat treatment is performed at 450 to 620 ° C. for 1 hour or more and 48 hours or less so that the intermetallic compound is not coarsened. When the heat treatment is shorter than 1 hour, the effect of the soaking treatment is insufficient.
Subsequently, hot rolling and cold rolling are performed to obtain an aluminum rolled sheet. Intermediate annealing may be performed before, after, or during hot rolling. The intermediate annealing conditions in this case are a method of heating at 280 to 600 ° C. for 2 to 20 hours, preferably 350 to 500 ° C. for 2 to 10 hours using a batch annealing furnace, and a continuous annealing furnace for 10 to 10 hours. When heated at a temperature elevation rate of 200 ° C./second, the crystal structure can be made finer.
The aluminum plate finished to a thickness of 0.1 to 0.5 mm by the above steps may be improved in flatness by a correction device such as a roller leveler or tension leveler in order to improve the flatness. The flatness may be improved after the aluminum plate is cut into a sheet, but in order to improve the productivity, it is preferable to improve the flatness in a continuous coil state.
[0022]
Further, a slitter line may be used to process the plate width to a predetermined width. Moreover, in order to prevent the generation | occurrence | production of the damage | wound by friction of aluminum plates, you may provide a thin oil film on the surface of an aluminum plate. As the oil film, a volatile or non-volatile film is appropriately used as necessary.
In addition, regarding cold rolling, the present inventors have disclosed in JP-A-6-210308. When continuous casting is performed, for example, if a cooling roll such as a Hunter method is used, a cast plate having a thickness of 1 to 10 mm can be directly continuously cast, and a merit that a hot rolling step can be omitted is obtained. Further, when a cooling roll such as the Husley method is used, a cast plate having a thickness of 10 to 50 mm can be cast. Generally, a hot rolling roll is arranged immediately after casting and continuously rolled, so that a thickness of 1 to 1 is obtained. A 10 mm continuous cast and rolled plate is obtained. These continuous cast and rolled sheets are finished to a thickness of 0.1 to 0.5 mm through processes such as cold rolling, intermediate annealing, flatness improvement, and slitting, as described in the case of DC casting. It is done. Regarding the intermediate annealing condition and the cold rolling condition when the continuous casting method is used, the present inventors have disclosed JP-A-6-220593, JP-A-6-210308, JP-A-7-54111, JP-A-8- No. 92709, etc.
When the aluminum plate produced by the above-described method is used as a support for a lithographic printing plate, various properties described below are desired depending on the application.
[0023]
Regarding strength: In order to obtain waist strength necessary for a printing plate support, it is desirable that the 0.2% proof stress is 140 MPa or more. Further, in order to obtain a certain level of waist strength even when the burning treatment is performed, the 0.2% proof stress after heating at 270 ° C. for 3 to 10 minutes is 80 MPa or more, preferably 100 MPa or more. In particular, when the strength of the waist is required, an aluminum material added with Mg or Mn can be used. However, since the ease of fitting to the plate cylinder of a printing press is inferior, depending on the application, the material The addition amount of the trace component is appropriately selected. With regard to these, the present applicant has disclosed in JP-A-7-126820, JP-A-62-2140894, and the like.
[0024]
Regarding the crystal structure: When a chemical surface treatment or an electrochemical surface treatment is performed as a support for a lithographic printing plate, surface defects may occur due to the crystal structure of the surface of the aluminum plate. The crystal structure is preferably not very coarse. The width of the crystal structure is 200 μm or less, preferably 100 μm or less, and more preferably 50 μm or less. The length of the crystal structure is 5000 μm or less, preferably 1000 μm or less, more preferably 500 μm or less. With regard to these, the present applicant has disclosed in JP-A-6-218495, JP-A-7-39906, JP-A-7-124609, and the like.
[0025]
Regarding alloy component distribution: When a chemical surface treatment or electrochemical surface treatment is performed as a support for a lithographic printing plate, poor surface quality is caused by uneven distribution of alloy components on the surface of the aluminum plate. In some cases, the distribution of alloy components on the surface is preferably not very uneven. With regard to these, the present applicant has disclosed in JP-A-6-48058, JP-A-5-301478, JP-A-7-13289, and the like.
Regarding intermetallic compounds: When performing a chemical surface treatment or an electrochemical surface treatment as a support for a lithographic printing plate, it may be affected by the size and density of the intermetallic compound. With regard to these, the present applicant has disclosed in JP-A-7-138687 and JP-A-4-254545.
[0026]
For example, a hardboard and felt are laid on an iron pallet, cardboard donut plates are applied to both ends of the product, the whole is wrapped with a polytube, a wooden donut is inserted into the inner diameter of the coil, and the outer periphery of the coil is felt. , Squeeze with strap and display on the outer periphery. Moreover, a polyethylene film is used as the packaging material, and needle felt and hard board are used as the cushioning material. There are various other forms, but it is important that they can be transported stably without scratches.
[0027]
The following surface treatment is performed on such an aluminum plate. This pretreatment is typically performed by removing rolling oil on the surface of the aluminum plate using a solvent such as trichlene or a surfactant, or by using an alkaline etching agent such as sodium hydroxide or potassium hydroxide. It is the exposure of the aluminum plate surface. Specifically, solvent degreasing methods include methods using petroleum solvents such as gasoline, kerosene, benzine, solvent naphtha, normal hexane, trichloroethylene, methylene chloride, perchlorethylene, 1,1,1-trichloroethane, etc. There is a method using a chlorinated solvent. Alkaline degreasing methods include methods using aqueous solutions of soda salts such as sodium hydroxide, sodium carbonate, sodium bicarbonate, sodium sulfate, sodium orthosilicate, sodium metasilicate, No. 2 sodium silicate, No. 3 sodium silicate, etc. There are a method using an aqueous solution of silicate, a method using an aqueous solution of phosphate such as monobasic sodium phosphate, tribasic sodium phosphate, dibasic sodium phosphate, sodium tripolyphosphate, sodium pyrophosphate and sodium hexametaphosphate. When the alkaline degreasing method is used, the aluminum surface may be dissolved depending on the treatment time and the treatment temperature. Therefore, the degreasing treatment needs not to be accompanied by a dissolution phenomenon. As the degreasing treatment with a surfactant, an anionic surfactant, a cationic surfactant, a nonionic surfactant, and an aqueous solution of an amphoteric surfactant can be used, and various commercially available products can be used. As a degreasing method, a dipping method, a spraying method, a method of rubbing a liquid in a cloth or the like can be used. Moreover, you may use an ultrasonic wave for the immersion or spraying method. Regarding the degreasing treatment, for example, JP-A-2-26793 can be referred to.
[0028]
The above metal support is subjected to mechanical surface roughening treatment, chemical dissolution treatment i, electrolytic surface roughening treatment, and chemical dissolution treatment ii in this order as disclosed in JP-A-11-87675. It is desirable to do in.
[Mechanical roughening]
This mechanical surface roughening includes methods such as transfer, brushing, and liquid honing, and can be used in combination in consideration of productivity. Various methods can be used as a transfer method for pressing the uneven surface against the aluminum plate. That is, in addition to the above-mentioned Japanese Patent Application Laid-Open Nos. 55-74898, 60-36195, and 60-20396, Japanese Patent Application No. 4-175945, which performs transfer several times. Japanese Patent Laid-Open No. 6-24168, which is characterized in that the handwriting and the surface are elastic, is also applicable. In addition, by using electrical discharge machining, shot blasting, laser, plasma etching, etc., transfer is repeatedly performed using a roll etched with fine irregularities, and the uneven surface coated with fine particles is contacted with an aluminum plate. Then, a concavo-convex pattern corresponding to the average diameter of the fine particles may be repeatedly transferred to the aluminum plate a plurality of times by applying a pressure repeatedly over the surface and applying a plurality of times. As methods for imparting fine irregularities to a transfer roll, JP-A-3-8635, JP-A-3-66404, JP-A-63-65017, and the like are known. Further, a fine groove may be cut from two directions using a die, a cutting tool, a laser, or the like on the roll surface, and the surface may be provided with square irregularities. The surface of the roll may be subjected to a process such that the formed square irregularities are rounded by performing a known etching process or the like. It goes without saying that quenching and hard chrome plating may be performed to increase the surface hardness.
[0029]
An example of a mechanical surface roughening process using a brush is as follows: a polishing slurry is uniformly dispersed on a traveled aluminum plate, and a brush roll is rotated on the surface to mechanically roughen the surface. I do. The polishing slurry can be dispersed and the surface roughened by a brush roll at two or more locations. When using a brush, the flexural modulus is 10,000 to 40,000 kg / cm.², Preferably 15,000-35,000 kg / cm²In addition, it is preferable to use a brush having a bristle strength of 500 g or less, preferably 400 g or less, and further using an abrasive having a particle size of 20 to 80 μm, preferably 30 to 60 μm. The material of the brush preferably has the above mechanical strength, and can be used other than the above mechanical strength. For example, it can be appropriately selected from synthetic resins and metals. Examples of the synthetic resin include polyamide such as nylon, polyolefin such as polypropylene, polyester such as polyvinyl chloride and polybutylene terephthalate, and polycarbonate. Examples of the metal include stainless steel and brass. Also, the material of the abrasive is preferably in the above particle size range, and the material is not limited, and is selected from alumina, silica, silicon carbide, silicon nitride, etc. that have been conventionally used for mechanical roughening treatment. Is done. The mechanical surface-roughening treatment is performed by pressing the roll brush having the brush bristles against the surface of the aluminum plate while rotating at high speed and supplying the abrasive to the roll brush. At this time, the number of rotations of the roll brush, the pressure contact force, the supply amount of the abrasive, etc. are not particularly limited. As an apparatus suitable for the mechanical surface roughening, for example, an apparatus described in Japanese Patent Publication No. 50-40047 can be given.
[0030]
A combination of a thin nylon brush (No. 0.9 to No. 3) and a fine abrasive (average particle size of 10 μm to 30 μm: pumice, silica sand, etc.) is particularly suitable for Ra to be 0.1 μm to 0.5 μm. .
[0031]
[Chemical dissolution treatment i]
After performing the mechanical surface roughening treatment as described above, the aluminum surface is subjected to chemical etching treatment using an alkaline solution having a pH of 11 or more, preferably 13 or more, for the purpose of smoothing and homogenizing the aluminum plate. .
[0032]
In the process of chemically etching the aluminum surface, the traveled aluminum plate is passed through an etching treatment tank, and in the treatment tank, an alkaline solution is sprayed and sprayed uniformly over the width direction of the aluminum plate. Surface etching is performed by spraying an etching solution mainly containing sodium oxide. When the aluminum plate leaves the etching bath, the surface of the plate is wiped with a nip roll to prevent the processing solution from being taken out of the bath.
[0033]
During the etching process, the sodium hydroxide component in the processing solution is reduced by the reaction, the aluminum ion content is increased, and the amount of the processing solution and the concentration of the components are changed, for example, water is evaporated and decreased. For this reason, sodium hydroxide solution and water are replenished to the treatment liquid in the liquid preparation tank, but the aluminum ions in the treatment liquid are maintained at a predetermined concentration by the replenishment liquid without removing the increasing aluminum ions. There is a lot of waste. For this reason, a part of the processing liquid in the preparation tank is circulated to the diffusion dialysis tank and the precipitation tank in a timely manner to remove aluminum ions from the system. In the diffusion dialysis tank, about 70% of the fed processing solution is recovered as a sodium hydroxide solution and returned to the preparation tank. On the other hand, the dialysis waste liquid that has become a supersaturated sodium aluminate solution by dialysis in a diffusion dialysis tank is sent to the precipitation tank. In the diffusion dialysis tank, water can be added to replenish the evaporated water. In the precipitation tank, the dialysis waste liquid from the diffusion dialysis tank and the treatment liquid from the preparation tank are mixed, and aluminum hydroxide is crystallized from the mixed liquid using the aluminum hydroxide seed in the supersaturated sodium aluminate solution as a nucleus. A mixture of a treatment solution mainly composed of sodium hydroxide solution from which aluminum ions have been removed and crystals of aluminum hydroxide is sent to a thickener, and the crystallized aluminum hydroxide is separated by a drum filter and collected in a hopper. On the other hand, the treatment liquid mainly composed of sodium hydroxide liquid is returned to the liquid preparation tank as a recovered liquid.
[0034]
In addition to the method using diffusion dialysis, a crystallization method for crystallization may be used. The etching amount in the chemical etching process is 3 g / m.²25 g / m²Or less, preferably 3 g / m²15 g / m or more²It is as follows. Etching amount is 3g / m²If it is less than this, the unevenness formed by the mechanical surface roughening treatment cannot be smoothed, and uniform pits cannot be generated in the subsequent electrolytic treatment. On the other hand, the etching amount is 25 g / m.²If it exceeds, the irregularities disappear. Usable alkaline solutions include, for example, sodium hydroxide aqueous solution such as sodium hydroxide, sodium carbonate, sodium bicarbonate, sodium sulfate, silicic acid such as sodium orthosilicate, sodium metasilicate, No. 2 sodium silicate, No. 3 sodium silicate Examples thereof include an aqueous salt solution, an aqueous phosphate solution such as monobasic sodium phosphate, dibasic sodium phosphate, tribasic sodium phosphate, sodium tripolyphosphate, sodium pyrophosphate, and sodium hexametaphosphate. The treatment conditions are an alkaline solution concentration of 0.01% to 50% by weight, a liquid temperature of 20 ° C. to 90 ° C., and a time of 5 seconds to 5 minutes, which are selected as appropriate so as to achieve the above etching amount.
[0035]
When the surface of the aluminum plate is chemically etched with the alkaline solution, an insoluble residue, that is, smut is generated on the surface. Therefore, the smut is removed by using an acidic solution having the same composition as that of the acidic solution used in the subsequent electrolytic surface roughening treatment. Preferred treatment conditions are a liquid temperature of 30 to 80 ° C. and a time of 3 seconds to 3 minutes.
Next, an electrolytic surface roughening treatment is performed on the aluminum plate thus treated.
[0036]
[Electrolytic roughening treatment]
The electrolytic surface-roughening treatment in the present invention is not particularly limited, but as described in JP-A No. 11-84675, first and second electrolysis by alternating waveform current in an acidic solution before and after the cathodic electrolysis treatment. It is preferable to carry out the treatment. Cathodic electrolytic treatment generates smut on the surface of the aluminum plate and generates hydrogen gas, thereby enabling more uniform electrolytic roughening. First, the 1st and 2nd electrolytic surface roughening process by the alternating waveform current in an acidic solution is demonstrated. In this electrolytic surface roughening treatment, the first treatment and the second treatment may be under the same conditions, or may be different within the range of preferred treatment conditions.
[0037]
An example of the process which performs an electrolytic surface-roughening process by the 1st and 2nd electrolytic surface-roughening process to an aluminum support body is shown. As an apparatus for subjecting an aluminum support to electrolytic surface roughening, there are a first surface side roughening treatment apparatus for electrolytically roughening the surface of the aluminum support, and a second surface side for electrolytically roughening the surface of the aluminum support. It consists of a roughening treatment apparatus and a back surface roughening treatment apparatus for electrolytically roughening the back side surface of the aluminum support. Each of the surface side roughening treatment device and the back surface roughening treatment device is provided with a pair of arc-shaped main electrodes connected to the electrolytic cell via an AC power source, and above the main electrodes. A freely rotatable drum roll is arranged. An electrolytic solution is filled between the main electrode and the drum roll. Further, a pass roll is disposed between the first surface side roughening treatment device, the second surface side roughening treatment device, and the back surface side roughening treatment device to form a travel path of the aluminum support. . In addition, the traveling path between the second surface side roughening apparatus and the back surface roughening apparatus is such that the surface is in contact with the drum roll and the back surface is immersed in the electrolyte in the back surface roughening apparatus. It is a reversal travel path that reverses the aluminum support. A plurality of sprays sprayed on the electrolytic solution aluminum support are provided in the reversing travel path.
[0038]
In order to manufacture the aluminum support with the apparatus as described above, the main electrode of each roughening treatment apparatus is energized and the aluminum support is run. Then, the surface of the aluminum support is continuously roughened by the first surface side roughening treatment device and the second surface side roughening treatment device. The aluminum support whose surface was roughened was inverted so that it passed through the reverse running path, the surface side was in contact with the drum roll of the back surface roughening device, and the back surface was immersed in the electrolyte. In the state, it is sent to the back surface roughening apparatus. And while driving | running | working this inversion driving | running route, an electrolyte solution is sprayed from a spray and the aluminum support body is always made into the wet state.
[0039]
This electrolytic surface roughening treatment can be performed according to the electrochemical grain method described in, for example, Japanese Patent Publication No. 48-28123 and British Patent No. 896563. This electrolytic graining uses a sinusoidal alternating current, but it may be performed using a special waveform as described in JP-A-52-58602. Further, the waveform described in JP-A-3-79799 can also be used. JP-A-55-158298, JP-A-56-28898, JP-A-52-58602, JP-A-52-152302, JP-A-54-85802, JP-A-60-190392, JP-A-58-120531. JP-A-63-176187, JP-A-1-5889, JP-A-1-280590, JP-A-1-118489, JP-A-1-148592, JP-A-1-178596, JP-A-1-188315, JP-A-1-188315. -154947, JP-A-2-235794, JP-A-3-260100, JP-A-3-253600, JP-A-4-72079, JP-A-4-72098, JP-A-3-267400, and JP-A-1-141994. Methods can also be applied. As the frequency, in addition to the above, those proposed for electrolytic capacitors can be used. For example, U.S. Pat. Nos. 4,276,129 and 4,676,879.
[0040]
Examples of the acidic solution that is an electrolytic solution include nitric acid, hydrochloric acid, and the like, as well as U.S. Pat. Electrolyte solutions such as those described in JP-A-4336113 and JP-A-4184932 can also be used. The concentration of the acidic solution is preferably 0.5 to 2.5% by weight, but 0.7 to 2.0% by weight is particularly preferable in consideration of use in the smut removal treatment. The liquid temperature is preferably 20 to 80 ° C, particularly preferably 30 to 60 ° C.
[0041]
Various electrolyzers and power sources have been proposed, such as U.S. Pat. No. 4,023,637, JP-A-56-123400, JP-A-57-59770, JP-A-53-12738, JP-A-53-32821. Japanese Unexamined Patent Publication No. 53-32822, Japanese Unexamined Patent Publication No. 53-32823, Japanese Unexamined Patent Publication No. 55-122896, Japanese Unexamined Patent Publication No. 55-132848, Japanese Unexamined Patent Publication No. 62-127500, Japanese Unexamined Patent Publication No. 1-52100, Japanese Unexamined Patent Publication No. 1-52098, Japanese Unexamined Patent Publication No. 60. -67700, JP-A-1-230800, JP-A-3-257199, and the like. Besides the above-mentioned patents, various proposals have been made. For example, Japanese Patent Laid-Open Nos. 52-58602, 52-152302, 53-12738, 53-12739, 53-32821, 53-32822, 53-32833 JP-A 53-32824, JP-A 53-32825, JP-A 54-85802, JP-A 55-122896, JP-A 55-132894, JP-B 48-28123, JP-B 51-7081, Of course, those described in JP-A-52-13338, JP-A-52-133840, JP-A-52-133844, JP-A-52-133845, JP-A-53-149135, JP-A-54-146234 are also applicable. it can.
[0042]
This electrolytic treatment is performed with an anode electricity quantity of 30 to 400 C / dm.² , Preferably 50 to 200 C / dm²Done in Anode electric quantity is 30C / dm²Below, no uniform pits are generated, while 400 C / dm²The pit will become too large if you cross over.
[0043]
During the first and second electrolytic surface roughening treatments, the aluminum plate is subjected to cathodic electrolytic treatment. By this cathodic electrolysis treatment, smut is generated on the surface of the aluminum plate, and hydrogen gas is generated to enable more uniform electrolytic roughening. This cathodic electrolysis treatment is carried out in an acidic solution with a cathode electric quantity of 3 to 80 C / dm.², Preferably 5-30 C / dm²Done in Cathode electricity is 3 C / dm²Is less than 80 C / dm.²Exceeding this ratio is not preferable because the amount of smut adhesion becomes excessive. Further, the electrolytic solution may be the same as or different from the solution used in the first and second electrolytic surface roughening processes.
[0044]
[Chemical dissolution treatment ii]
After the electrolytic surface roughening treatment, the aluminum plate is subjected to a second chemical etching treatment using an alkaline solution having a pH of 11 or more. The alkaline solution having a pH of 11 or more used in the second chemical etching process may be the same as the alkaline solution used in the first chemical etching process, or a different alkaline solution may be used. However, the etching amount is 0.1 to 8 g / m, different from the first chemical etching process.², Preferably 0.2 to 3.0 g / m²More preferably, 0.5 to 1.5 g / m²It is. Etching amount is 0.1g / m²If the ratio is less than 8 g / m, the pit end obtained by the electrolytic treatment cannot be smoothed.²If you cross over, the pit disappears.
[0045]
Since the smut is generated by the chemical etching process, the aluminum plate is removed using a solution mainly containing sulfuric acid. Here, the solution mainly composed of sulfuric acid is a mixed solution obtained by appropriately mixing phosphoric acid, nitric acid, chromic acid, hydrochloric acid and the like in addition to a sulfuric acid single solution. For the removal of smut using a solution mainly composed of sulfuric acid, reference can be made to, for example, JP-A-53-12739. Moreover, you may combine alkali treatment and can refer, for example, Unexamined-Japanese-Patent No. 56-51388. Further, JP-A-60-8091, JP-A-63-176188, JP-A-1-38291, JP-A-1-127389, JP-A-1-188699, JP-A-3-177600, JP-A-3-126891, and JP-A-3-12689. The methods described in each of the 1911100 publications can also be used in combination.
[0046]
[Anodic oxidation treatment]
Next, an anodized film is formed on the surface of the aluminum plate. An example of the process of anodizing the surface of an aluminum plate is shown. The aluminum plate is transported and charged to (+) by the feeding electrode in the feeding tank in which the electrolyte is stored. And an aluminum plate is conveyed toward an electrolytic treatment tank. Next, the aluminum plate is charged to (−) by the electrolytic electrode, whereby an anodized film is formed on the surface thereof, and the aluminum plate exiting the electrolytic treatment tank is conveyed to a subsequent process. The feeding electrode and the electrolytic electrode are connected to a DC power source. Using such an anodizing apparatus, an anodic oxide film can be formed by energizing an aluminum plate as an anode in a solution having a sulfuric acid concentration of 50 to 300 g / liter and an aluminum concentration of 5% by weight or less. The solution may contain phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid and the like. The amount of oxide film formed is 1.0 to 5.0 g / m.², Especially 1.5-4.0 g / m²It is preferable that Since the treatment conditions for anodization vary depending on the electrolyte used, it cannot be generally stated, but in general, the concentration of the electrolyte is 1 to 80% by weight, the solution temperature is 5 to 70 ° C., and the current density is 0.8. 5-60A / dm²The voltage is in the range of 1 to 100 V, the electrolysis time is 15 seconds to 50 minutes, and the pore structure is adjusted.
[0047]
For example, it is known that if the type of the electrolytic solution is the same, the pore diameter of the pore generated by electrolysis is proportional to the electrolytic voltage. By gradually increasing the electrolysis voltage using this property, a pore with an expanded bottom is generated.
In addition, it is known that the pore diameter changes greatly when the type of the electrolyte is changed. Roughly speaking, the pore diameter in the sulfuric acid electrolyte <the pore diameter in the oxalic acid electrolyte <the phosphoric acid electrolyte The pore diameter. Therefore, it is possible to change the electrolyte solution and perform the treatment twice, or connect the treatment equipment in two or three steps and perform the treatment continuously in two or three stages to form an anodized film structure. Is possible.
In the present invention, the pores at the surface mouth portion of the anodized film are particularly improved by a method in which an electrolytic voltage is increased using a phosphoric acid electrolyte and a method in which the first stage is sulfuric acid and the second stage is phosphoric acid. While maintaining the diameter, a film having a large pore at the bottom was obtained and evaluated, but the production method is not limited to these.
[0048]
<Method for determining the amount of anodized film>
The amount of anodized film is proportional to the amount of electricity applied. The quantity of electricity has the relationship of the following formula 1.
[0049]
Electricity [Coulomb / m²] = Current [A / m²] X processing time [seconds] Equation 1
[0050]
Therefore, in the case of the constant current method, by changing the treatment time, electrolysis, measuring the film amount by JIS-H8680-7 (film weight method), and creating a calibration curve, the desired film amount is obtained. It is possible to determine the corresponding processing time.
However, since JIS-H8680-7 (film weight method) is used by boiling a powerful drug such as an aqueous chromic acid solution, it is unsafe and takes time. Therefore, a fluorescent X-ray analyzer can be simply substituted. That is, a part of the calibration curve sample was measured for the coating amount by JIS-H8680-7 (film weight method), and a part of the calibration curve sample was actually measured for the scattering intensity by fluorescent X-ray analysis (Rh Lα ray Compton scattering line). Thus, a calibration curve can be created and the amount of film can be measured. The example sample of this specification is an anodized film (170 g / liter, 33 ° C., 5 A / dm) using ordinary sulfuric acid.²), The treatment time was changed to obtain a calibration curve sample, and the electrolytic treatment time was adjusted to obtain a desired film amount by fluorescent X-ray analysis.
For the sake of simplification, even if the type of the electrolytic solution was changed to phosphoric acid or the like, a calibration curve prepared using sulfuric acid was used without changing the calibration curve.
[0051]
<Measurement method of pore diameter and internal maximum diameter of pores in anodized film>
High resolution TEM (transmission electron microscope) or ultra high resolution SEM (scanning electron microscope) is used to observe the film structure for measuring the pore diameter and maximum internal diameter of the anodized film. I can do it. Observation by TEM is very time-consuming because it is necessary to cut out and observe an ultrathin section using an apparatus called a microtome. Therefore, it is usually desirable to use an ultra-high resolution SEM. Hitachi S-900 was used in the examples and comparative examples in this specification.
The pore diameter of the pores of the anodized film was observed at a magnification of 5 to 200,000 times with a relatively low accelerating voltage of 12 V and without performing a vapor deposition treatment for imparting conductivity, The pores were randomized and the average value was used. The standard deviation error was ± 10% or less. In addition, the maximum internal diameter of the pores of the anodized film is determined by bending the anodized aluminum plate and forming the side surface (commonly referred to as the fracture surface) of the cracked portion generated when the anodized aluminum plate is bent into an ultra-high resolution SEM (Hitachi S-900). ) And observed. The bottom part of the fracture surface of the anodized film is observed at an appropriate magnification without conducting vapor deposition treatment that imparts conductivity at a relatively low acceleration voltage of 12 V, and 50 pores are randomly extracted. Average values were used. The standard deviation error was ± 10% or less.
[0052]
[Sealing treatment]
The sealing treatment is a treatment for closing the hole of the porous anodic oxide film with a metal oxide, hydroxide, salt or the like.
As a typical sealing treatment method, water glass such as sodium silicate and potassium silicate is diluted, applied or dipped and dried, and a chemical called a sealing agent is added to steam and hot water in an appropriate amount. There is a method of forming a sealing film by exposing the sealing treatment liquid by a method such as immersion or spraying.
[0053]
Typical sealants include sodium fluoride, calcium fluoride, potassium fluoride, magnesium fluoride, barium fluoride, chromium fluoride, lithium fluoride, manganese fluoride, nickel fluoride, iron fluoride. , Phosphoric acid phosphoric acid, ammonium fluorophosphate, potassium fluoroaluminate, sodium hexafluorozirconium, sodium hexafluorotitanate, potassium hexafluorotitanate, hexafluorozirconium hydroacid, hexafluorotitanium hydroacid, hexafluorotitanium Ammonium acid, hexafluorosilicic acid and the like can be mentioned, and these can be used alone or in admixture of two or more. Of these, sodium fluoride and potassium fluoride are particularly preferred. The concentration of the inorganic fluorine compound in the treatment liquid is suitably in the range of 0.1 to 40% by weight, preferably 0.1 to 10% by weight. If it is 1% by weight or more, relatively large particles are produced and the intended effect cannot be obtained. If it exceeds 40% by weight, the particle diameter becomes too small or the aluminum plate is easily etched, which is not preferable.
[0054]
The treatment liquid containing the inorganic fluorine compound contains another phosphorus compound that does not interfere with the generation of particles and does not etch the aluminum plate. Examples thereof include phosphoric acid and aluminum salts, ammonium salts, sodium salts, potassium salts, calcium salts, zinc salts, magnesium salts, lithium salts, and the like thereof.
[0055]
Specifically, for example, zinc phosphate, aluminum phosphate, ammonium phosphate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, monoammonium phosphate, monopotassium phosphate, monosodium phosphate, dihydrogen phosphate Potassium, dipotassium hydrogen phosphate, calcium phosphate, sodium ammonium hydrogen phosphate, diammonium hydrogen phosphate, magnesium hydrogen phosphate, magnesium phosphate, ferrous phosphate, ferric phosphate, sodium dihydrogen phosphate, phosphorus Sodium phosphate, disodium hydrogen phosphate, lead phosphate, diammonium phosphate, calcium dihydrogen phosphate, lithium phosphate, phosphotungstic acid, ammonium phosphotungstate, sodium tungstate phosphate, ammonium phosphomolybdate, phosphomolybdenum Sodium salt . Further, phosphonic acids such as sodium phosphite, sodium tripolyphosphate, sodium pyrophosphate, aminoethylphosphonic acid, phenylphosphonic acid and the like can be mentioned. Preferred examples include sodium dihydrogen phosphate, disodium hydrogen phosphate, potassium dihydrogen phosphate, and dipotassium hydrogen phosphate. These may be used alone or in combination of two or more.
[0056]
The concentration when the above compound is added to the treatment liquid is suitably less than 50% by weight, and if it exceeds 50% by weight, it does not dissolve, prevents the formation of particles with a preferred particle size, This is not preferable because the surface anodized film is etched. Desirably, it is around 10% by weight.
As the treatment method, a dipping method, a spraying method, a spraying method, a coating method and the like are suitable. The treatment temperature is suitably 60 to 100 ° C., the treatment time is suitably 30 to 300 seconds, and the pH is preferably 1.0 to 6.5. During such treatment, a direct current or alternating current can be passed to treat the aluminum plate in the same way as anodization, and in this case, the treatment time can be shortened. Further, if the treatment concentration is increased or the treatment time is lengthened, the amount of product is too much, which causes stains during printing, which is not preferable. The aluminum support thus treated is usually washed with water, but the surface can be further treated if necessary.
As a more preferred surface treatment, treatment with an aqueous solution of phosphoric acid and ammonium salt or alkali metal salt, and further, for example, treatment for providing an undercoat layer made of a water-soluble compound such as polyacrylic acid, polyvinyl alcohol, polyvinylphosphonic acid, Examples thereof include a treatment for undercoating a dye or pigment for preventing halation.
In addition, a method of attaching the granular product to the aluminum support more firmly by hot water at 50 ° C. or higher and / or hot air treatment or steam treatment is desirable.
[0057]
As the sealing treatment, a sealing treatment in which exposure is performed in a steam atmosphere for 10 seconds to 30 seconds, or 0.1 wt% NaF / 10 wt% NaH.₂PO_FourA treatment in which an aqueous solution (using pure water) is immersed for 10 to 30 seconds at 90 ° C. to 100 ° C. is desirable.
The optimum state of the sealing amount was observed using the method for observing the surface mouth diameter of the anodized film described in << Method for measuring the pore diameter of the pore of the anodized film and the internal maximum diameter >> It is desirable that the mouth is not observed, petals, needle-like projections, etc. are not observed, and the surface is almost flat.
[0058]
The surface of the metal support subjected to the above treatment has a center line average roughness (Ra) of 0.1 to 0.5 μm and an average roughness (Rz) of 1.0 to 5.0 μm. Is preferred. When Ra exceeds 0.5 μm, the adhesion to the image forming layer is improved, but when forming an image by laser exposure, the image forming layer tends to remain in the concave portion, so it is necessary to increase the laser irradiation intensity. In addition, it causes a decrease in sensitivity, and the reflected light at the interface between the image forming layer and the metal support is irregularly reflected.
[0059]
<< Ra measurement method with surface roughness meter >>
The center line surface roughness (JIS-BO601-1970) is preferably 0.1 to 0.5 μm. The centerline surface roughness when electrochemical surface roughening, chemical etching, and desmut treatment are added to the surface roughness after mechanical roughening, chemical etching, and desmutting treatment. It is preferably 0.9 to 1.5 times.
[0060]
[Image forming layer]
The image forming layer of the lithographic printing plate precursor according to the invention contains a photothermal conversion agent and is classified into the following three types.
Type I: Melting removal (ablation) by heat causes the laser-irradiated portion of the uppermost imageable layer to scatter in the air, and a metal layer appears on the uppermost layer side. (Ablation positive)
Type II: The uppermost imageable layer is decomposed and softened by heat, so that it becomes soluble in the developer and the film strength deteriorates significantly. The irradiated part is removed. (Thermal positive)
Type III: The uppermost imageable layer is polymerized and cured by heat to change to a property insoluble in the developer, and the film strength is remarkably enhanced. The irradiated part is removed. (Thermal negative)
Type IV: The uppermost imageable layer is polymerized and cured by heat, so that the film strength is remarkably enhanced. On the other hand, the laser non-irradiated part is easily removed by water or rubbing. (On-press development type thermal negative)
[0061]
[Ablation positive type image forming layer]
Specific examples of type I include inorganic materials such as Cr, Ti, Pb-Sb-Sn ternary alloys known as type alloys, metals such as metals, coal, charcoal, diamond, DLC. (Diamond-like coating), carbons such as graphite and classy carbon, oxides, nitrides, silicides and carbides. Moreover, not only a simple substance but a mixture may be sufficient.
[0062]
Specific examples of the above include aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, hafnium oxide, vanadium oxide, niobium oxide, tantalum oxide, molybdenum oxide, tungsten oxide, and chromium oxide. In addition, aluminum nitride, silicon nitride, titanium nitride, zirconium nitride, hafnium nitride, vanadium nitride, niobium nitride, tantalum nitride, molybdenum nitride, tungsten nitride, chromium nitride, silicon nitride, Examples thereof include boron nitride. In addition, titanium silicide, zirconium silicide, hafnium silicide, vanadium silicide, niobium silicide, tantalum silicide, molybdenum silicide, tungsten silicide, chromium silicide, and the like can be given. In addition, titanium boride, zirconium boride, hafnium boride, vanadium boride, niobium boride, tantalum boride, molybdenum boride, tungsten boride, chromium boride, and the like can be given. Further, aluminum carbide, silicon carbide, titanium carbide, zirconium carbide, hafnium carbide, vanadium carbide, niobium carbide, tantalum carbide, molybdenum carbide, tungsten carbide, chromium carbide, and the like can be given.
[0063]
Since these inorganic substances have a high light absorptance of light having a wavelength of 760 to 1064 nm, such as YAG laser and LD laser, among the inorganic substances, a layer capable of forming an image by heat is ablated and peeled off.
Among them, Cr, Ti, Pb—Sb—Sn, diamond, DLC, TiO exhibiting ink affinity₂, BaTiO_Three, SrTiO_Three, Si_ThreeN_FourSiC or the like is desirable. Vapor deposition, CVD, sol-gel method, sputtering method, ion plating method, diffusion method, electrodeposition method, plating method and the like can be appropriately used for forming the image-forming layer.
Moreover, after ablation, as generally performed, a step of physically scraping with a brush or the like may be used in combination to remove the residue.
[0064]
Specific examples of the organic substance include PMMA (polymethyl methacrylate), EMA-styrene, polystyrene, and novolac, which are generally known as ink-philic polymers. Since these polymers have a low light absorptance of light having a wavelength of a writing laser (760 to 1064 nm), it is necessary to dissolve, disperse or mix an appropriate photothermal conversion material. As a photothermal conversion material, various commercially available YAGs, light absorbing dyes having a wavelength of LD laser, such as Cyasorb IR-165 (American Cyanamid), Epolight III-117, Epolight III-130, and Epolight III-180 can be used. In addition, various inorganic substances described in the specific examples of type I inorganic substances may be dispersed and mixed in the polymer as powders. Various undercoats may be applied to improve the adhesion between the image forming layer and the support.
[0065]
[Thermal positive image forming layer]
The type II thermal positive image forming layer contains at least a polymer compound that becomes alkali-soluble by heat and a photothermal conversion agent described in detail later.
Examples of the polymer compound that is used for the thermal positive image forming layer and becomes alkali-soluble by heat include resins having an acid group such as a phenolic hydroxyl group or a carboxy group. Examples of the resin having a phenolic hydroxyl group include a resol type phenol resin and a novolac type phenol resin, and among these, a novolac resin is preferable. Examples of the novolak resin that can be suitably used in the present invention include phenol formaldehyde resin, m-cresol formaldehyde resin, p-cresol formaldehyde resin, o-cresol formaldehyde resin, m- / p-mixed cresol formaldehyde resin, phenol / cresol ( m-, p-, o-, and m- / p-, m- / o-, o- / p-mixed)) cresol formaldehyde resins such as mixed formaldehyde resins. Resol-type phenol resins are also preferably used, and phenol / cresol (m-, p-, o- and m- / p-, m- / o-, o- / p-mixed) mixed formaldehyde Resins are preferable, and phenol resins described in JP-A-61-217034 are particularly preferable.
[0066]
Other polymer compounds that become alkali-soluble by heat include, for example, a copolymer containing a carboxy group. For example, a copolymer of a monomer having at least one unsaturated bond polymerizable with a carboxy group (COOH group) in one molecule is preferable. Examples of the monomer having a carboxy group include methacrylic acid, acrylic acid, itaconic acid, and the like, but monomers other than those shown in the following general formulas (I) to (III) are also preferably used.
[0067]
[Chemical 1]

[0068]
R¹, R^Three, R^FiveRepresents hydrogen or a methyl group, R², R^Four, R⁶, R⁷Represents an optionally substituted alkylene group having 1 to 12 carbon atoms, cycloalkylene group, arylene group, or aralkylene group, and X represents —O— or —NR.⁸-Represents Y and represents a single bond or a -CO- group. R⁸Represents a hydrogen atom, an optionally substituted alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, an aryl group or an aralkyl group. Specifically, N- (4-carboxyphenyl) -methacrylamide, N- (2-carboxyphenyl) -acrylamide, N- (4-chloro-2-carboxyphenyl) -methacrylamide, 4-carboxyphenylethyl methacrylate, Examples include 4-carboxystyrene and 2-carboxyphenyloxyethyl acrylate.
[0069]
As a monomer for imparting the property of being alkali-soluble by heat to a polymer compound other than the monomer having a carboxy group, a sulfonamide group in which at least one hydrogen atom is bonded to a nitrogen atom in one molecule; Monomers composed of low molecular weight compounds each having one or more polymerizable unsaturated bonds are preferred. Among these, a monomer composed of a low molecular compound having an acryloyl group, an allyl group or a vinyloxy group and an unsubstituted or monosubstituted aminosulfonyl group or a substituted sulfonylamino group is preferable. Examples of such compounds include compounds represented by the following general formulas (IV) to (VIII).
[0070]
[Chemical 2]

[0071]
Where X¹, X²Are —O— or —NR, respectively.¹⁷-Represents. R¹, R^FourAre each a hydrogen atom or -CH_ThreeRepresents. R², R^Five, R⁸, R¹¹, R¹⁵Each represents an alkylene group having 1 to 12 carbon atoms, a cycloalkylene group, an arylene group or an aralkylene group which may have a substituent. R^Three, R¹⁷, R¹²Represents a hydrogen atom, an optionally substituted alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, an aryl group or an aralkyl group. R⁶, R¹⁶Represents an optionally substituted alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, an aryl group or an aralkyl group. R⁷, R⁹, R¹³Is a hydrogen atom or -CH_ThreeRepresents. R^Ten, R¹⁴Each represents a C1-C12 alkylene group, cycloalkylene group, arylene group or aralkylene group which may have a single bond or a substituent. Y¹, Y²Each represents a single bond or —CO—.
Specifically, m-aminosulfonylphenyl methacrylate, N- (p-aminosulfonylphenyl) methacrylamide, N- (p-toluenesulfonyl) acrylamide and the like can be preferably used.
[0072]
In addition to the above (IV) to (VIII), other monomers include -CO-NH-SO in one molecule.₂A monomer composed of a low molecular weight compound having at least one active imino group represented by-and one or more polymerizable unsaturated bonds is also preferred. As such a compound, specifically, N- (m-aminosulfonyl) methacrylamide, N- (p-aminosulfonyl) methacrylamide, N- (p-toluenesulfonyl) acrylamide and the like are preferably used. Can do. Moreover, the monomer which consists of acrylamide, methacrylamide, acrylic ester, methacrylic ester, or hydroxystyrene which has a phenolic hydroxyl group is also preferably used as another monomer. Specific examples of such compounds include N- (4-hydroxyphenyl) acrylamide, N- (4-hydroxyphenyl) methacrylamide, o-, m-, p-hydroxyphenyl acrylate, o-, m-, p-hydroxystyrene etc. are mentioned.
[0073]
As a copolymerization component of the monomer, for example, monomers listed in the following (1) to (11) can be used, and two or more of the following monomers may be included.
(1) Acrylic acid esters and methacrylic acid esters having an aliphatic hydroxyl group such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate.
(2) Methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, glycidyl acrylate, N-dimethylaminoethyl acrylate Alkyl acrylates such as
(3) Methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-chloroethyl methacrylate, glycidyl methacrylate, N-dimethylaminoethyl Alkyl methacrylate such as methacrylate.
(4) Acrylamide, methacrylamide, N-methylolacrylamide, N-ethylacrylamide, N-hexylmethacrylamide, N-cyclohexylacrylamide, N-hydroxyethylacrylamide, N-phenylacrylamide, N-nitrophenylacrylamide, N-ethyl- Acrylamide or methacrylamide such as N-phenylacrylamide.
[0074]
(5) Vinyl ethers such as ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, and phenyl vinyl ether.
(6) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate.
(7) Styrenes such as styrene, α-methylstyrene, methylstyrene, and chloromethylstyrene.
(8) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone.
(9) Olefins such as ethylene, propylene, isobutylene, butadiene, and isoprene.
(10) N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine, acrylonitrile, methacrylonitrile and the like.
(11) Unsaturated imides such as maleimide, N-acryloylacrylamide, N-acetylmethacrylamide, N-propionylmethacrylamide, N- (p-chlorobenzoyl) methacrylamide.
[0075]
The polymer compound that becomes alkali-soluble by these heats preferably has a weight average molecular weight of 500 to 200,000 and a number average molecular weight of 200 to 60,000. The polymer compound that becomes alkali-soluble by heat may be used alone or in combination of two or more, and is 5 to 99% by weight, preferably 10 to 95% by weight, particularly 10% to 95% by weight, based on the total solid content of the thermal positive type image forming layer. It is preferably used in an addition amount of 20 to 90% by weight. If the addition amount is less than 5% by weight, the durability of the image forming layer is deteriorated, and if it exceeds 99% by weight, it is not preferable in terms of both sensitivity and durability.
In addition to the polymer compound that becomes alkali-soluble by heat, a binder is preferably added to the thermal positive image forming layer. Examples of the binder include a urethane resin, and among them, a urethane resin having a carboxy group or a sulfonamide group is preferable. That is, the polyurethane resin suitably used in the present invention is a polyurethane having a basic skeleton as a reaction product of a diisocyanate compound and a diol compound containing a sulfonamide group having at least one H atom bonded to N. Resin.
[0076]
Examples of the diisocyanate compound preferably used in the present invention include 2,4-tolylene diisocyanate, dimer of 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, and p-xylylene diene. Aromatic diesters such as isocyanate, m-xylylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, 3,3′-dimethylbiphenyl-4,4′-diisocyanate Isocyanate compounds; fatty acid diisocyanate compounds such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, dimer acid diisocyanate; isophorone diisocyanate, 4,4′-methylenebis (cyclohexylisocyanate) Nat), methylcyclohexane An alicyclic diisocyanate compound such as 2,4 (or 2,6) diisocyanate, 1,3- (isocyanatomethyl) cyclohexane; 1 mol of 1,3-butylene glycol and 2 mol of tolylene diisocyanate Examples thereof include a diisocyanate compound which is a reaction product of a diol such as an adduct and a diisocyanate.
[0077]
Examples of the diol compound containing a sulfonamide group in which at least one H atom is bonded to N include p- (1,1-dihydroxymethylethylcarbonylamino) benzenesulfonamide, p- (1,1-dihydroxymethyl). N-ethyl form of ethylcarbonylamino) benzenesulfonamide, N- (m-methylsulfonylaminophenyl) -2,2-dihydroxymethylpropanamide, N- (p-methylsulfonylaminophenyl) -2,2-dihydroxymethyl Propanamide, N- (m-ethylsulfonylaminophenyl) -2,2-dihydroxymethylpropanamide, N- (p-ethylsulfonylaminophenyl) -2,2-dihydroxymethylpropanamide, N- (2,2- (Dihydroxyethylaminocarbonyl) Le) methanesulfonamide, N- (2,2- (dihydroxy ethylaminocarbonyl) ethyl benzene sulfonamide, N- (2,2- (dihydroxy ethylaminocarbonyl) ethyl -p- toluenesulfonamide, and the like.
[0078]
These diol compounds containing sulfonamide groups can be used alone or in combination of two or more. Furthermore, a diol compound that does not have a sulfonamide group and may have other substituents that do not react with isocyanate can be used in combination with a diol compound having a sulfonamide group. Examples of such diol compounds include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, neopentyl glycol, 1,3-butylene glycol, and 1,6-hexane. Diol, 2-butyl-1,4-diol, 2,2,4-trimethyl-1,3-pentanediol, 1,4-bis-β-hydroxyethoxycyclohexane, cyclohexanedimethanol, tricyclodecane dimethanol, water Bisphenol A, hydrogenated bisphenol F, ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A, ethylene oxide adduct of bisphenol F Propylene oxide adduct of bisphenol F, ethylene oxide adduct of hydrogenated bisphenol A, propylene oxide adduct of hydrogenated bisphenol A, hydroquinone dihydroxyethyl ether, p-xylylene glycol, dihydroxyethyl sulfone, bis (2-hydroxyethyl) -2,4-tolylene dicarbamate, 2,4-tolylene-bis (2-hydroxyethylcarbamide), bis (2-hydroxyethyl) -m-xylylenedicarbamate, bis (2-hydroxyethyl) isophthalate, 3, 5-dihydroxybenzoic acid, 2,2-bis (hydroxymethyl) propionic acid, 2,2-bis (2-hydroxyethyl) propionic acid, 2,2-bis (3-hydroxypropyl) propionic acid, bis (hydroxymethyl) )vinegar Examples include acid, bis (4-hydroxyphenyl) acetic acid, 4,4-bis (4-hydroxyphenyl) pentanoic acid, and tartaric acid.
[0079]
The polyurethane resin that can be used in the present invention is synthesized by adding the above-mentioned diisocyanate compound and diol compound to an aprotic solvent and adding a known catalyst having an activity corresponding to the respective reactivity and heating. The molar ratio of the diisocyanate and diol compound used is preferably 0.8: 1 to 1.2: 1, more preferably 0.85: 1.1 to 1.1: 1, and an isocyanate group at the polymer end. When this is left, the terminal is treated with alcohols or amines to synthesize a polyurethane resin having no isocyanate group remaining.
The weight average molecular weight of the urethane resin that can be used in the present invention is preferably 2,000 or more, more preferably 5,000 to 300,000. The number average molecular weight is preferably 1,000 or more, more preferably in the range of 2,000 to 250,000. The polydispersity (weight average molecular weight / number average molecular weight) is preferably 1 or more, more preferably 1.1 to 10.
Moreover, the binder which can be used for this invention may contain the unreacted monomer. In this case, the proportion of the monomer in the binder is desirably 15% by weight or less. The above-mentioned binders can be used alone, but it is also preferable to mix one or more binders. Among them, it is preferable to use a novolak resin and other binders mixed together.
[0080]
Various additives can be further added to the thermal positive image forming layer of the present invention as required. For example, it is thermally decomposable, such as an onium salt, o-quinonediazide compound, aromatic sulfone compound, aromatic sulfonic acid ester compound, etc., and in the state where it does not decompose, the solubility of the polymer compound that becomes alkali-soluble by heat is substantially reduced. It is preferable to use a substance to be used in combination from the viewpoint of improving the dissolution inhibition of the image area in the developer. Examples of onium salts include diazonium salts, ammonium salts, phosphonium salts, iodonium salts, sulfonium salts, selenonium salts, and arsonium salts.
[0081]
Preferred examples of the onium salt used in the present invention include SI Schlesinger, Photogr. Sci. Eng., 18, 387 (1974), TS Bal et al, Polymer, 21, 423 (1980), -158230, U.S. Pat. Nos. 4,069,055 and 4,069,056, ammonium salts described in JP-A-3-140140, DC Necker et al, Macromolecules, 17, 2468 (1984), CS Wen et al., Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), U.S. Pat.Nos. 4,069,055, 4,069,056, JVCrivello et al, Macromorecules, 10 (6), 1307 ( 1977), Chem. & Eng. News, Nov. 28, p31 (1988), European Patent No. 104,143, U.S. Pat.Nos. 339,049, 410,201, JP-A-2-150848, JP-A-2-96514 Iodonium salts described, JVCrivello et al, Polymer J. 17, 73 (1985), JV Crivello et al. J. Org. Chem., 43, 3055 (1978), WR Watt et al, J. Polymer Sci., Polymer Chem. Ed., 22, 1789 (1984), JV Crivello et al, Polymer Bull., 14, 279 (1985), JV Crivello et al, Macromorecules, 14 (5), 1141 (1981), JV Crivello et al, J. Polymer Sci., Polymer Chem. Ed., 17, 2877 (1979), European Patents 370,693, 233,567, 297,443, 297,442, U.S. Patents 4,933,377, 3,902,114, 410,201 , 339,049, 4,760,013, 4,734,444, 2,833,827, German Patents 2,904,626, 3,604,580, 3,604,581, sulfonium salts described in JV Crivello et al, Macromorecules, 10 (6), 1307 (1977), Selenium salt described in JV Crivello et al, J. Polymer Sci., Polymer Chem. Ed., 17, 1047 (1979), CS Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 And arsonium salts described in Tokyo, Oct (1988).
[0082]
In the present invention, a diazonium salt is particularly preferable. Particularly suitable diazonium salts include those described in JP-A-5-158230.
Suitable quinonediazides include o-quinonediazide compounds. The o-quinonediazide compound used in the present invention is a compound having at least one o-quinonediazide group, which increases alkali solubility by thermal decomposition, and compounds having various structures can be used. That is, o-quinonediazide assists the solubility of the photosensitive material system by both the effects of losing the ability to suppress the dissolution of the binder by thermal decomposition and the change of o-quinonediazide itself into an alkali-soluble substance. Examples of the o-quinonediazide compound used in the present invention include J. Although compounds described in pages 339 to 352 of “Light-Sensitive Systems” by Korser can be used, they are particularly reacted with various aromatic polyhydroxy compounds or aromatic amino compounds. -Sulphonic esters or sulphonic amides of quinonediazides are preferred. Further, benzoquinone (1,2) -diazide sulfonic acid chloride or naphthoquinone- (1,2) -diazide-5-sulfonic acid chloride and pyrogallol-acetone resin as described in JP-B-43-28403 Esters of benzoquinone- (1,2) -diazidosulfonic acid chloride or naphthoquinone- (1,2) -diazido-5-sulfonic acid chloride and phenol described in US Pat. Nos. 3,046,120 and 3,188,210 Esters with formaldehyde resins are also preferably used.
[0083]
Further, an ester of naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride and phenol formaldehyde resin or cresol-formaldehyde resin, naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride and pyrogallol-acetone resin Similarly, the esters are also preferably used. Other useful o-quinonediazide compounds are reported and known in numerous patents. For example, JP 475303, JP 48-63802, JP 48-63803, JP 48-96575, JP 49-38701, JP 48-13354, No. 41-11222, JP-B 45-9610, JP-B 49-17481, U.S. Pat.Nos. 2,797,213, 3,454,400, 3,544,323, 3,573,917, 3,674,495, and 3,785,825 And British Patents 1,227,602, 1,251,345, 1,267,005, 1,329,888, 1,330,932, and German Patent 854,890.
The addition amount of the o-quinonediazide compound is preferably in the range of 1 to 50% by weight, more preferably 5 to 30% by weight, particularly preferably 10 to 30% by weight, based on the total solid content of the thermal positive type image forming layer. . These compounds can be used alone, but may be used as a mixture of several kinds.
[0084]
The counter ion of the onium salt includes tetrafluoroboric acid, hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid, 5-nitro-o-toluenesulfonic acid, 5-sulfosalicylic acid, 2,5-dimethylbenzenesulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, 2-nitrobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, 3-bromobenzenesulfonic acid, 2-fluorocaprylnaphthalenesulfonic acid, dodecylbenzenesulfonic acid, 1-naphthol-5-sulfone Examples include acid, 2-methoxy-4-hydroxy-5-benzoyl-benzenesulfonic acid, and paratoluenesulfonic acid. Of these, alkyl aromatic sulfonic acids such as hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid and 2,5-dimethylbenzenesulfonic acid are particularly preferred.
The amount of additives other than the o-quinonediazide compound is preferably 1 to 50% by weight, more preferably 5 to 30% by weight, and particularly preferably 10 to 30% by weight, based on the total solid content of the thermal positive type image forming layer. It is.
[0085]
Further, for the purpose of improving sensitivity, cyclic acid anhydrides, phenols, and organic acids can be used in combination. Examples of cyclic acid anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, and 3,6-endooxy-Δ4-tetrahydrophthalic anhydride described in US Pat. No. 4,115,128. Tetrachlorophthalic anhydride, maleic anhydride, chloromaleic anhydride, α-phenylmaleic anhydride, succinic anhydride, pyromellitic anhydride and the like can be used. As phenols, bisphenol A, p-nitrophenol, p-ethoxyphenol, 2,4,4'-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4-hydroxybenzophenone, 4,4 ', 4 ″ -Trihydroxytriphenylmethane, 4,4 ′, 3 ″, 4 ″ -tetrahydroxy-3,5,3 ′, 5′-tetramethyltriphenylmethane and the like. There are sulfonic acids, sulfinic acids, alkylsulfuric acids, phosphonic acids, phosphoric esters, carboxylic acids and the like described in Japanese Laid-Open Patent Application No. 60-88942, JP-A-2-96755, and the like. p-toluenesulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfinic acid, ethyl sulfate, phenyl Sphonic acid, phenylphosphinic acid, phenyl phosphate, diphenyl phosphate, benzoic acid, isophthalic acid, adipic acid, p-toluic acid, 3,4-dimethoxybenzoic acid, phthalic acid, terephthalic acid, 4-cyclohexene-1,2 -Dicarboxylic acid, erucic acid, lauric acid, n-undecanoic acid, ascorbic acid, etc. are mentioned.
[0086]
The proportion of the cyclic acid anhydride, phenols and organic acids in the image forming layer is preferably 0.05 to 20% by weight, more preferably 0.1 to 15% by weight, most preferably 0.1 to 0.1% by weight. 10% by weight. Further, in the image forming layer in the present invention, in order to widen the stability of the processing with respect to the developing conditions, the nonionic surface activity as described in JP-A-62-251740 and JP-A-3-208514 is used. An amphoteric surfactant as described in JP-A-59-121044 and JP-A-4-13149 can be added.
[0087]
Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan trioleate, stearic acid monoglyceride, polyoxyethylene nonylphenyl ether and the like. Specific examples of the double-sided activator include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine and N-tetradecyl-N, N-betaine. Examples thereof include trade names (for example, trade name Amorgen K, manufactured by Daiichi Kogyo Co., Ltd.). The nonionic surfactant and amphoteric surfactant are preferably 0.05 to 15% by weight, more preferably 0.1 to 5% by weight, based on the total solid content of the thermal positive type image forming layer.
[0088]
[Thermal negative type image forming layer]
The type III thermal negative image forming layer contains at least a polymer having a structural unit represented by the following general formula (IX), a thermal crosslinking agent, an acid generator, and a photothermal conversion agent described in detail later.
[0089]
[Chemical 3]

[0090]
In general formula (IX), R¹Represents a hydrogen atom or a methyl group. X¹Represents an alkali-soluble per se or a linking group having an alkali-soluble group. Here, the alkali-soluble group refers to a group containing a moiety such as sulfonic acid amide, sulfonic acid imide, or carboxylic acid imide, specifically, —SO₂NH-, -NHSO₂-, -SO₂NHCO-, -CONHSO₂-, -CONHCO- and the like can be mentioned. Ar¹Represents an aromatic hydrocarbon group having 20 or less carbon atoms which may have a substituent. Specific examples include a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthrene ring. Among these aromatic hydrocarbon groups, a benzene ring or a naphthalene ring is preferable from the viewpoint of availability and economy.
[0091]
Moreover, as a preferable substituent which these aromatic hydrocarbon groups can have, a C20 or less hydrocarbon group, a halogen atom, a cyano group, a nitro group, a carboxyl group, a carbamoyl group, etc. can be mentioned. Y¹Is N-R^ThreeRepresents an oxygen atom or a sulfur atom, R²Represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Where R^ThreeRepresents a hydrogen atom or a hydrocarbon group having 20 or less carbon atoms which may have a substituent. R²And R^ThreePreferred substituents that can be used in the above are halogen atom, cyano group, nitro group, carboxyl group, carbamoyl group, alkoxyl group having 20 or less carbon atoms, perfluoroalkyl group having 20 or less carbon atoms, and hydroxyalkyl having 20 or less carbon atoms. Groups and the like. Moreover, n shows the integer of 1-4. L¹Represents a single bond, an ester bond, a carboxylic acid amide bond, a sulfonic acid amide bond, an ether bond, a thioether bond or a hydrocarbon group having 20 or less carbon atoms, which may contain these bonds. L²Represents a single bond or a hydrocarbon group having 20 or less carbon atoms, and is preferably a single bond from the viewpoint of availability and economy.
[0092]
R²And Ar¹And R^ThreeAnd Ar¹And R²And R^ThreeEach may form a ring structure such as a cyclohexane ring. The polymer having a structural unit represented by the general formula (IX) that is preferably used in the present invention is a polymer having a structural unit represented by the following general formula (X). In addition, in general formula (X), the same code | symbol as the code | symbol of general formula (IX) is attached | subjected, and description is abbreviate | omitted.
[0093]
[Formula 4]

[0094]
Where R^FourAnd R^FiveThese may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 20 or less carbon atoms which may have a substituent. R^FourAnd R^FivePreferred substituents that can be used in the above are halogen atom, cyano group, nitro group, carboxyl group, carbamoyl group, alkoxyl group having 20 or less carbon atoms, perfluoroalkyl group having 20 or less carbon atoms, and hydroxyalkyl having 20 or less carbon atoms. Groups and the like. R^FourAnd R^FiveMay form a ring structure such as a condensed benzene ring or a cyclohexane ring. The polymer having the structural unit represented by the general formula (X) can be obtained by radical polymerization by a conventionally known method using the corresponding monomer represented by the general formula (XI).
In addition, in general formula (XI), the same code | symbol as the code | symbol of general formula (X) is attached | subjected, and description is abbreviate | omitted.
[0095]
[Chemical formula 5]

[0096]
In this invention, the example of the monomer represented by general formula (XI) used suitably is given to the following as formula (XI-1)-(XI-13). In the following formula, R¹Represents a hydrogen atom or a methyl group, Z¹Represents an oxygen atom or NH.
[0097]
[Chemical 6]

[0098]
[Chemical 7]

[0099]
[Chemical 8]

[0100]
In the present invention, suitable polymers having a structural unit represented by general formula (IX) include homopolymers using only one kind of monomer represented by general formula (XI) and copolymers using two or more kinds. Both polymers can be used. The polymer that can be used in the present invention is a copolymer of a monomer represented by the general formula (XI) and a conventionally known polymerizable monomer other than the monomer represented by the general formula (XI). Is preferable from the viewpoint of solubility in the coating solution and flexibility of the coating film.
Examples of known monomers used in combination with the monomer represented by the general formula (XI) include, for example, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, 2-hydroxyethyl. Acrylic acid esters such as acrylate and benzyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, 2-hydroxyethyl methacrylate, methacrylic acid esters such as benzyl methacrylate, acrylonitrile, etc. It is done.
[0101]
The polymer having a structural unit represented by the general formula (IX) of the present invention is a linking group having an alkali solubility as a partial structure thereof (for example, an acidic group)¹Therefore, it is excellent in solubility in alkaline water, but may be a copolymer using a monomer having another acidic group as an auxiliary. Examples of the monomer used include acrylic acid, methacrylic acid, itaconic acid, maleic acid, N- (2-carboxyethyl) acrylamide, N- (2-carboxyethyl) methacrylamide, N- (carboxyphenyl) acrylamide, N- (Carboxyphenyl) methacrylamide, carboxystyrene, maleimide, N- (phenylsulfonyl) acrylamide, N- (phenylsulfonyl) methacrylamide, N- (tolylsulfonyl) acrylamide, N- (tolylsulfonyl) methacrylamide, N- (chlorophenyl) Sulfonyl) acrylamide, N- (chlorophenylsulfonyl) methacrylamide, N- (sulfamoylphenyl) acrylamide, N- (sulfamoylphenyl) methacrylamide, N- (methyls) Famoylphenyl) acrylamide, N- (methylsulfamoylphenyl) methacrylamide, N- (phenylsulfamoylphenyl) acrylamide, N- (phenylsulfamoylphenyl) methacrylamide, N- (tolylsulfamoylphenyl) Acrylamide, N- (tolylsulfamoylphenyl) methacrylamide, N-[(chlorophenylsulfamoyl) phenyl] acrylamide, N-[(chlorophenylsulfamoyl) phenyl] methacrylamide, N- (hydroxyphenyl) acrylamide, N -(Hydroxyphenyl) methacrylamide, N- (hydroxynaphthyl) acrylamide, N- (hydroxynaphthyl) methacrylamide and the like.
[0102]
Moreover, although it is not an acidic group, salts of strong acids such as sodium salt of p-styrenesulfonic acid, alkali metal salt of 2-acrylamido-2-methylpropanesulfonic acid, tetraalkylammonium salt, potassium salt of 3-sulfopropyl acrylate, etc. Is preferable as a component of the copolymer because it can improve the solubility in water and, as a result, improve the developability of the image forming layer in an aqueous developer.
The proportion of the structural unit represented by the general formula (IX) contained in the copolymer using these is preferably 20 to 95% by weight, more preferably 30 to 90% by weight. Further, the weight average molecular weight of the polymer having the structural unit represented by the general formula (IX) contained in the thermal negative image forming layer is preferably 5000 or more, and more preferably in the range of 10,000 to 300,000. The number average molecular weight is preferably 1000 or more, more preferably in the range of 2000 to 250,000. The polydispersity (weight average molecular weight / number average molecular weight) is preferably 1 or more, and more preferably 1.1 to 10. These polymers may be random polymers, block polymers, graft polymers or the like, but are preferably random polymers.
[0103]
Examples of the solvent used when synthesizing the polymer having the structural unit represented by the general formula (IX) include tetrahydrofuran, ethylene dichloride, cyclohexanone, methyl ethyl ketone, acetone, methanol, ethanol, ethylene glycol monomethyl ether, ethylene glycol mono Ethyl ether, 2-methoxyethyl acetate, diethylene glycol dimethyl ether, 1-methoxy-2-propanol, 1-methoxy-2-propyl acetate, N, N-dimethylformamide, N, N-dimethylacetamide, toluene, ethyl acetate, methyl lactate , Ethyl lactate, dimethyl sulfoxide, water and the like. These solvents may be used alone or in combination of two or more. As the radical polymerization initiator used in the synthesis, known compounds such as azo initiators and peroxide initiators can be used. The polymer having the structural unit represented by the general formula (IX) may be used alone or in combination, and is 20 to 95% by weight, preferably 40 to 90% by weight, based on the total solid content of the thermal negative image forming layer. % In the image forming material. When the addition amount is less than 20% by weight, the strength of the image portion is insufficient when an image is formed. If the addition amount exceeds 95% by weight, no image is formed.
[0104]
Examples of the thermal crosslinking agent used in the thermal negative image forming layer include compounds having two or more hydroxymethyl groups, alkoxymethyl groups, epoxy groups or vinyl ether groups in the molecule. A compound in which these crosslinkable functional groups are directly bonded to an aromatic ring is preferable. Specific examples include methylol melamine, resol resin, epoxidized novolac resin, urea resin and the like. Furthermore, the compounds described in “Crosslinking agent handbook” (Shinzo Yamashita, Tosuke Kaneko, Taiseisha Co., Ltd.) are also preferred. In particular, a phenol derivative having two or more hydroxymethyl groups or alkoxymethyl groups in the molecule is preferable because the strength of the image area when forming an image is good. A specific example of such a phenol derivative is a resole resin. However, these thermal crosslinking agents are naturally unstable to heat, and the stability during storage after the image forming material is prepared is not so good. In contrast, phenol derivatives having 4 to 8 benzene nuclei, at least one phenolic hydroxyl group and at least two groups represented by the formula (XII) in the molecule have good stability during storage. Are most preferably used.
[0105]
[Chemical 9]

[0106]
R of (XII)⁶Represents a hydrogen atom, an alkyl group or an acyl group, and the alkyl group includes a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group or a t-butyl group. Such an alkyl group having 1 to 4 carbon atoms is preferably a formyl group, acetyl group, butyryl group, benzoyl group, cinnamoyl group or valeryl group as the acyl group. Moreover, C1-C4 substituted alkyl groups, such as a methoxyethyl group, a methoxypropyl group, a hydroxyethyl group, a hydroxypropyl group, can be used.
Phenol derivatives that can be used in the thermal negative type image forming layer include known phenol compounds, for example, JP-A-1-289946, 3-179353, 3-200252, 3-128959, The phenol compounds described in JP-A-3-200244, JP-A-5-158233, and JP-A-5-224409 and formaldehyde in a strong alkaline medium at a temperature of about 0 to 80 ° C, preferably 10 to 60 ° C. By reacting for 1 to 30 hours at⁶= H is obtained.
[0107]
Thereafter, by further reacting with an alcohol having 1 to 4 carbon atoms, a substituted alcohol, an acid halide or an acid anhydride at 0 to 80 ° C. for 1 to 30 hours under acidic conditions, R⁶= Alkyl, acyl. The temperature at the time of reacting with the alcohol or the substituted alcohol is preferably 20 to 80 ° C., and the temperature at the time of reacting with the acid halide or acid anhydride is preferably 0 to 30 ° C. Specific examples of the phenol derivative that can be used in the present invention include, but are not limited to, compounds represented by the following general formulas (XIII) to (XX). These phenol derivatives may be used alone or in admixture of two or more, but the amount used is 0.2 to 60% by weight, preferably 0, in the thermal negative image forming layer. 0.5 to 20% by weight. In addition, a compound having 1 to 3 benzene nuclei and having a phenolic hydroxyl group and a group represented by the formula (XII) causes a decrease in the wall-thickness and development tolerance. It is desirable to be substantially free of compounds. More specifically, it is desirably 5% by weight or less in the thermal negative image forming layer, more preferably 3% by weight or less, and most preferably 0% by weight.
[0108]
[Chemical Formula 10]

[0109]
Embedded image

[0110]
Embedded image

[0111]
Embedded image

[0112]
Where R⁷~ R⁹, R¹⁴, R^{twenty two}, R^{twenty three}Represents a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group, and R^Ten, R¹⁸~ R^{twenty one}Represents a hydrogen atom or an alkyl group, R¹¹~ R¹³Represents a hydrogen atom, a halogen atom or an alkyl group, and R¹⁵~ R¹⁷Represents a single bond, an alkylene group which may have a substituent, an alkenylene group, a phenylene group, a naphthylene group, a carbonyl group, an ether group, a thioether group, an amide bond or a combination of two or more thereof, and Y represents a general formula A group represented by (XII), a, b, c, d, x, y represent an integer of 0-3, a + b + c + d + x + y is an integer of 2-16, and k, l, m, n are 0 to 3 integers are shown, but not all 0, e, f, g, h, p, q, r, s, t, u are integers 0 to 3, and z is 0 or 1 is shown.
Specific examples of the compounds represented by the general formulas (XIII) to (XX) include those having the following structures.
[0113]
Embedded image

[0114]
Embedded image

[0115]
Embedded image

[0116]
Embedded image

[0117]
Where Y²~ Y¹³Represents a hydrogen atom or a group represented by the formula (XII), and at least two of each compound have a group represented by the formula (XII), and preferably all are represented by the formula (XII). Group. Examples of other thermal crosslinking agents that are preferably used in the present invention include aldehydes and ketone compounds. A compound having two or more aldehydes or ketones in the molecule is preferable. These thermal crosslinking agents may be used alone or in combination of two or more. In the present invention, the thermal crosslinking agent is used in an amount of 5 to 70% by weight, preferably 10 to 65% by weight, in the solid content of the thermal negative image forming layer. If the addition amount of the thermal crosslinking agent is less than 5% by weight, the film strength of the image area at the time of image formation is deteriorated.
[0118]
Furthermore, an acid generator is added to the thermal negative image forming layer. The acid generator is a compound that decomposes by light or heating at 100 ° C. or higher to generate an acid, and the generated acid is preferably a strong acid having a pKa of 2 or less, such as sulfonic acid and hydrochloric acid. Examples of the acid generator suitably used in the present invention include onium salts such as iodonium salts, sulfonium salts, phosphonium salts, and diazonium salts. Specific examples include compounds described in US Pat. No. 4,708,925 and JP-A-7-20629. In particular, iodonium salts, sulfonium salts, and diazonium salts having a sulfonate ion as a counter ion are preferable.
[0119]
Examples of the diazonium salt include diazonium compounds described in U.S. Pat. No. 3,867,147, diazonium compounds described in U.S. Pat. No. 2,632,703, and diazo resins described in JP-A-1-102456 and JP-A-1-102457. Is also preferable. Also preferred are benzyl sulfonates described in US 5,135,838 and US 5,200,544. Furthermore, active sulfonic acid esters and disulfonyl compounds described in JP-A-2-100054, JP-A-2-100055 and JP-A-9-197671 are also preferred. In addition, haloalkyl-substituted S-triazines described in JP-A-7-271029 are also preferable.
These compounds may be used alone or in combination of two or more. These compounds are added in a proportion of 0.01 to 50% by weight, preferably 0.1 to 25% by weight, more preferably 0.5 to 15% by weight, based on the total solid content of the thermal negative image forming layer. When the addition amount is less than 0.01% by weight, an image cannot be obtained. On the other hand, when the added amount exceeds 50% by weight, the non-image area is stained during printing.
[0120]
Various additives can be further added to the thermal negative image forming layer as necessary. For example, a polyfunctional monomer having two or more ethylenic double bonds capable of radical polymerization in the molecule can be added. Such compounds include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, hexanediol di (meth) acrylate, trimethylolethane tri (meth) acrylate, and trimethylolpropane. Examples include tri (meth) acrylate, pentaerythritol, and tri-, tetra-, or hexa (meth) acrylate of dipentaerythritol. The addition amount of these polyfunctional monomers is 30% by weight or less in the thermal negative image forming layer.
[0121]
[On-machine development thermal negative image forming layer]
The type IV on-press development thermal negative image forming layer contains microcapsules encapsulating a fine particle polymer having a heat-reactive sensitive group or a compound having a heat-reactive sensitive group.
[0122]
Examples of the thermally reactive functional group include an ethylenically unsaturated group that undergoes a polymerization reaction (eg, acryloyl group, methacryloyl group, vinyl group, and allyl group), an isocyanate group that undergoes an addition reaction, or a block thereof, and a reaction thereof. Functional group having active hydrogen atom as a partner (for example, amino group, hydroxyl group, carboxyl group, etc.), epoxy group that similarly performs addition reaction, amino group, carboxyl group or hydroxyl group that is the reaction partner, condensation reaction is performed Examples thereof include a carboxyl group and a hydroxyl group or amino group, an acid anhydride that performs a ring-opening addition reaction, an amino group, or a hydroxyl group. However, any functional group capable of performing any reaction may be used as long as a chemical bond is formed.
[0123]
The fine particle polymer having a heat-reactive functional group used in the on-machine development thermal negative image forming layer includes acryloyl group, methacryloyl group, vinyl group, allyl group, epoxy group, amino group, hydroxyl group, carboxyl group, isocyanate. Mention may be made of those having groups, acid anhydrides and groups protecting them. Introduction of these functional groups into the polymer particles may be performed at the time of polymerization, or may be performed using a polymer reaction after the polymerization.
[0124]
When introduced at the time of polymerization, it is preferable to carry out emulsion polymerization or suspension polymerization of the monomer having these functional groups.
Specific examples of monomers having such functional groups include allyl methacrylate, allyl acrylate, vinyl methacrylate, vinyl acrylate, glycidyl methacrylate, glycidyl acrylate, 2-isocyanate ethyl methacrylate, block isocyanates based on alcohols thereof, 2-isocyanate ethyl acrylate, and the like. Block isocyanate with alcohol, 2-aminoethyl methacrylate, 2-aminoethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, acrylic acid, methacrylic acid, maleic anhydride, bifunctional acrylate, bifunctional methacrylate However, it is not limited to these.
[0125]
Examples of the monomer having no heat-reactive functional group that can be copolymerized with these monomers include styrene, alkyl acrylate, alkyl methacrylate, acrylonitrile, and vinyl acetate. The monomer is not limited as long as it has no monomer.
Examples of the polymer reaction used when the introduction of the heat-reactive functional group is performed after the polymerization include a polymer reaction described in WO96-34316.
[0126]
Among the fine particle polymers having the above-mentioned heat-reactive functional groups, those in which the fine particle polymers are coalesced by heat are preferred, and those having a hydrophilic surface and being dispersed in water are particularly preferred. The contact angle of the film when it was prepared by applying only fine polymer and drying at a temperature lower than the solidification temperature (water droplets), and the contact angle of the film produced by drying at a temperature higher than the solidification temperature ( It is preferable to be lower than the water droplets in the air. In order to make the fine particle polymer surface hydrophilic in this way, hydrophilic polymers or oligomers such as polyvinyl alcohol and polyethylene glycol, or hydrophilic low molecular weight compounds may be adsorbed on the fine particle polymer surface. It is not limited to.
[0127]
The solidification temperature of the fine particle polymer having these heat-reactive functional groups is preferably 70 ° C. or higher, but more preferably 100 ° C. or higher in view of stability over time.
The average particle size of the fine particle polymer is preferably 0.01 to 20 μm, more preferably 0.05 to 2.0 μm, and particularly preferably 0.1 to 1.0 μm. Within this range, good resolution and stability over time can be obtained.
The addition amount of the fine particle polymer having a reactive functional group is preferably 50% by weight or more, and more preferably 60% by weight or more based on the solid content of the on-press developing thermal negative image forming layer.
[0128]
The microcapsule used for the on-press developing thermal negative image forming layer contains a compound having a heat-reactive functional group. Examples of the compound having a thermally reactive functional group include a polymerizable unsaturated group, a hydroxyl group, a carboxyl group, a carboxylate group, an acid anhydride group, an amino group, an epoxy group, an isocyanate group, and an isocyanate block body. be able to.
[0129]
The compound having a polymerizable unsaturated group is preferably a compound having at least one ethylenically unsaturated bond, for example, an acryloyl group, a methacryloyl group, a vinyl group, an allyl group, etc., preferably two or more. Are widely known in the industrial field, and these can be used without particular limitation in the present invention. These are, as chemical forms, monomers, prepolymers, ie dimers, trimers and oligomers, or mixtures thereof, and copolymers thereof.
[0130]
Examples include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), esters thereof, unsaturated carboxylic acid amides, preferably unsaturated carboxylic acids and Examples include esters with aliphatic polyhydric alcohols and amides of unsaturated carboxylic acids with aliphatic polyvalent amines.
Further, an addition reaction product of an unsaturated carboxylic acid ester or unsaturated carboxylic acid amide having a nucleophilic substituent such as a hydroxyl group, an amino group, a mercapto group and the like with a monofunctional or polyfunctional isocyanate or epoxide, and a monofunctional or A dehydration condensation reaction product with a polyfunctional carboxylic acid is also preferably used.
In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an isocyanate group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, and further a halogen group or a tosyloxy group A substitution reaction product of an unsaturated carboxylic acid ester or amide having a leaving substituent such as monofunctional or polyfunctional alcohol, amine or thiol is also suitable.
Another preferred example is a compound obtained by replacing the unsaturated carboxylic acid with unsaturated phosphonic acid or chloromethylstyrene.
[0131]
Specific examples of the polymerizable compound that is an ester of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol include acrylic acid esters such as ethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butanediol diacrylate, tetra Methylene glycol diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate, trimethylolpropane tris (acryloyloxypropyl) ether, trimethylolethane triacrylate, hexanediol diacrylate, 1,4-cyclohexanediol diacrylate, tetraethylene glycol diacrylate, pentaerythritol diacrylate , Pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate, tris (acryloyl) Oxyethyl) isocyanurate, polyester acrylate oligomer and the like.
[0132]
Methacrylic acid esters include tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, Hexanediol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol hexamethacrylate, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis [p- (3-methacryloyloxy- 2-hydroxy Propoxy) phenyl] dimethyl methane, bis - [p- (can be given methacryloyloxy ethoxy) phenyl] dimethyl methane.
[0133]
Itaconic acid esters include ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate, 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol diitaconate And sorbitol tetritaconate.
[0134]
Examples of crotonic acid esters include ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate, and sorbitol tetradicrotonate.
Examples of isocrotonic acid esters include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, and sorbitol tetraisocrotonate.
Examples of maleic acid esters include ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate, and sorbitol tetramaleate.
[0135]
Examples of other esters include aliphatic alcohol esters described in JP-B-46-27926, JP-B-51-47334, JP-A-57-196231, JP-A-59-5240, JP Examples thereof include those having an aromatic skeleton described in JP-A-59-5241 and JP-A-2-226149, and those containing an amino group described in JP-A-1-165613.
[0136]
Specific examples of amide monomers of aliphatic polyvalent amine compounds and unsaturated carboxylic acids include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6-hexamethylene bis. -Methacrylamide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, xylylene bismethacrylamide and the like.
Examples of other preferable amide monomers include those having a cyclohexylene structure described in JP-B No. 54-21726.
[0137]
Further, urethane-based addition polymerizable compounds produced by using an addition reaction of isocyanate and hydroxyl group are also suitable. Specific examples thereof include, for example, one molecule described in JP-B-48-41708. A urethane compound containing two or more polymerizable unsaturated groups in one molecule obtained by adding an unsaturated monomer having a hydroxyl group represented by the following formula (II) to a polyisocyanate compound having two or more isocyanate groups. Etc.
[0138]
Formula (II)
CH₂= C (R¹) COOCH₂CH (R²) OH
(However, R¹And R²Are respectively H or CH_ThreeIndicates. )
[0139]
Further, urethane acrylates as described in JP-A-51-37193, JP-B-2-32293, JP-B-2-16765, JP-B 58-49860, JP-B 56-17654, JP-B Urethane compounds having an ethylene oxide skeleton described in JP-A-62-39417 and JP-B-62-39418 can also be mentioned as suitable examples.
Furthermore, radically polymerizable compounds having an amino structure or a sulfide structure in the molecule described in JP-A-63-277653, JP-A-63-260909, and JP-A-1-105238 are preferably listed. Can do.
[0140]
Examples of other suitable ones include polyester acrylates and epoxy resins as described in JP-A-48-64183, JP-B-49-43191, and JP-A-52-30490. Mention may be made of polyfunctional acrylates and methacrylates such as epoxy acrylates reacted with (meth) acrylic acid. In addition, specific unsaturated compounds described in JP-B-46-43946, JP-B-1-40337, JP-A-1-40336, vinylphosphonic acid compounds described in JP-A-2-25493, and the like are also included. It can be mentioned as a suitable thing. In some cases, compounds containing a perfluoroalkyl group described in JP-A-61-22048 are also preferably used. Further, those introduced as photocurable monomers and oligomers in Journal of Japan Adhesion Association, Vol. 20, No. 7, pages 300 to 308 (1984) can also be suitably used.
[0141]
Suitable epoxy compounds include glycerin polyglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene diglycidyl ether, trimethylolpropane polyglycidyl ether, sorbitol polyglycidyl ether, bisphenols or polyphenols or hydrogenated polyglycidyl ethers. Etc.
[0142]
Suitable isocyanate compounds include tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, xylylene diisocyanate, naphthalene diisocyanate, cyclohexanephenylene diisocyanate, hexamethylene diisocyanate, cyclohexyl diisocyanate, or alcohols or amines thereof. Mention may be made of blocked compounds.
Suitable amine compounds include ethylenediamine, diethylenetriamine, triethylenetetramine, hexamethylenediamine, propylenediamine, polyethyleneimine and the like.
[0143]
Preferred examples of the compound having a hydroxyl group include a compound having a terminal methylol group, a polyhydric alcohol such as pentaerythritol, and bisphenol / polyphenols.
Preferred examples of the compound having a carboxyl group include aromatic polyvalent carboxylic acids such as pyromellitic acid, trimellitic acid and phthalic acid, and aliphatic polyvalent carboxylic acids such as adipic acid.
Suitable acid anhydrides include pyromellitic acid anhydride and benzophenone tetracarboxylic acid anhydride.
[0144]
Preferable examples of the copolymer of ethylenically unsaturated compounds include a copolymer of allyl methacrylate. For example, allyl methacrylate / methacrylic acid copolymer, allyl methacrylate / ethyl methacrylate copolymer, allyl methacrylate / butyl methacrylate copolymer and the like can be mentioned.
[0145]
As a method of microencapsulation, a known method can be applied. For example, as a method for producing microcapsules, a method using coacervation as shown in U.S. Pat. Nos. 2,800,547 and 2,800,498, British Patent No. 990443, U.S. Pat. No. 3,287,154, Japanese Patent Publication No. 38-19574, No. 42-446. No. 42-711, an interfacial polymerization method, US Pat. No. 3,418,250, US Pat. No. 3,660,304, a method of polymer precipitation, US Pat. No. 3,796,669, a method using an isocyanate polyol wall material, US Pat. No. 3,914,511. Using an isocyanate wall material found in US Pat. No. 4,001,140, US Pat. No. 4,087,376, US Pat. No. 4,089,802, a method using a urea-formaldehyde-based or urea-formaldehyde-resorcinol-based wall forming material, A method using a wall material such as melamine-formaldehyde resin and hydroxycellulose as shown in Japanese Patent No. 4025445, an in situ method by monomer polymerization as shown in Japanese Patent Publication Nos. 36-9163 and 51-9079, British Patent No. 930422 Examples thereof include, but are not limited to, the spray drying method found in US Pat. No. 3111407, and the electrolytic dispersion cooling method shown in British Patent Nos. 952807 and 967074.
[0146]
A preferable microcapsule wall used in the on-press developing thermal negative image forming layer has a three-dimensional cross-linking and a property of swelling by a solvent. From such a viewpoint, the wall material of the microcapsule is preferably polyurea, polyurethane, polyester, polycarbonate, polyamide, and a mixture thereof, and particularly preferably polyurea and polyurethane. A compound having a thermally reactive functional group may be introduced into the microcapsule wall.
[0147]
The average particle size of the microcapsules is preferably 0.01 to 20 μm, more preferably 0.05 to 2.0 μm, and particularly preferably 0.10 to 1.0 μm. Within this range, good resolution and stability over time can be obtained.
Such microcapsules may be combined with each other by heat or may not be combined. In short, among the microcapsule inclusions, the one that oozes out of the capsule surface or outside the microcapsule at the time of application, or the one that enters the microcapsule wall may cause a chemical reaction by heat. You may react with the added hydrophilic resin or the added low molecular weight compound. In addition, two or more types of microcapsules may be reacted with each other by providing functional groups that react with each other with different functional groups.
Therefore, it is preferable for image formation that the microcapsules are fused and merged by heat, but it is not essential.
[0148]
The addition amount of the microcapsule to the on-press development thermal negative image forming layer is preferably 10 to 60% by weight, more preferably 15 to 40% by weight in terms of solid content. Within this range, good on-press developability and good sensitivity and printing durability can be obtained.
[0149]
When the microcapsules are added to the on-press development thermal negative image forming layer, a solvent capable of dissolving the inclusion and swelling the wall material can be added to the microcapsule dispersion medium. By such a solvent, diffusion of the encapsulated compound having a heat-reactive functional group to the outside of the microcapsule is promoted.
Such a solvent depends on the microcapsule dispersion medium, the material of the microcapsule wall, the wall thickness, and the inclusion, but can be easily selected from many commercially available solvents. For example, in the case of water-dispersible microcapsules composed of crosslinked polyurea and polyurethane walls, alcohols, ethers, acetals, esters, ketones, polyhydric alcohols, amides, amines, fatty acids and the like are preferable.
[0150]
Specific compounds include methanol, ethanol, tertiary butanol, n-propanol, tetrahydrofuran, methyl lactate, ethyl lactate, methyl ethyl ketone, propylene glycol monomethyl ether, ethylene glycol diethyl ether, ethylene glycol monomethyl ether, γ-butyl lactone, N, There are N-dimethylformamide, N, N-dimethylacetamide, and the like, but not limited thereto. Two or more of these solvents may be used.
[0151]
A solvent that does not dissolve in the microcapsule dispersion but dissolves when the solvent is mixed can also be used. The amount to be added is determined by the combination of materials, but is usually preferably 5 to 95% by weight of the coating solution, more preferably 10 to 90% by weight, and particularly preferably 15 to 85% by weight.
[0152]
Since the fine particle polymer or microcapsule having a thermally reactive group is used for the on-press development thermal negative image forming layer, a compound that initiates or accelerates these reactions may be added as necessary. Examples of the compound that initiates or accelerates the reaction include compounds that generate radicals or cations by heat, such as lophine dimer, trihalomethyl compound, peroxide, azo compound, diazonium salt, or diphenyliodonium salt. And onium salts, acylphosphine, imide sulfonate and the like.
These compounds can be added in the range of 1 to 20% by weight of the solid content of the on-press developing thermal negative image forming layer. Preferably it is the range of 3 to 10 weight%. Within this range, good reaction initiation or acceleration effect can be obtained without impairing on-press developability.
[0153]
A hydrophilic resin may be added to the on-press developing thermal negative image forming layer. Addition of the hydrophilic resin not only improves the on-press developability, but also improves the film strength of the on-press development thermal negative image forming layer itself.
As the hydrophilic resin, those having a hydrophilic group such as hydroxyl, carboxyl, hydroxyethyl, hydroxypropyl, amino, aminoethyl, aminopropyl, carboxymethyl and the like are preferable.
[0154]
Specific examples of hydrophilic resins include gum arabic, casein, gelatin, starch derivatives, carboxymethylcellulose and its sodium salt, cellulose acetate, sodium alginate, vinyl acetate-maleic acid copolymers, styrene-maleic acid copolymers, polyacrylic acids and Salts thereof, polymethacrylic acids and their salts, homopolymers and copolymers of hydroxyethyl methacrylate, homopolymers and copolymers of hydroxyethyl acrylate, homopolymers and copolymers of hydroxypropyl methacrylate, homopolymers and copolymers of hydroxypropyl acrylate, hydroxybutyl Homopolymers and copolymers of methacrylate, homopolymers and copolymers of hydroxybutyl acrylate Homopolymers of limers, polyethylene glycols, hydroxypropylene polymers, polyvinyl alcohols, and hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, acrylamide having a degree of hydrolysis of at least 60% by weight, preferably at least 80% by weight And copolymers, methacrylamide homopolymers and polymers, N-methylolacrylamide homopolymers and copolymers, and the like.
[0155]
The addition amount of the hydrophilic resin to the on-press development thermal negative image forming layer is preferably 5 to 40% by weight, more preferably 10 to 30% by weight of the solid content of the layer. Within this range, good on-press developability and film strength can be obtained.
[0156]
The thermal positive type image forming layer, the thermal negative type image forming layer and the on-machine development thermal negative type image forming layer described in detail above commonly have a photothermal conversion agent for converting light such as laser light into heat, and the necessity. Accordingly, a printing-out agent for obtaining a visible image immediately after heating by exposure, a dye or pigment as an image colorant, or a plasticizer for imparting flexibility or the like to the image forming layer is added.
[0157]
In the present invention, various pigments or dyes can be used as the photothermal conversion agent. Examples of pigments include commercially available pigment and color index (CI) manuals, “Latest Pigment Handbook” (edited by the Japan Pigment Technology Association, published in 1977), “Latest Pigment Applied Technology” (published by CMC, published in 1986), “Printing” The pigments described in "Ink Technology", published by CMC Publishing, 1984) can be used.
Examples of the pigment include black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and other polymer-bonded dyes. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments In addition, quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like can be used.
[0158]
These pigments may be used without surface treatment or may be used after surface treatment. Surface treatment methods include a method of surface coating with a resin or wax, a method of attaching a surfactant, a method of bonding a reactive substance (eg, a silane coupling agent, an epoxy compound, polyisocyanate, etc.) to the pigment surface, etc. Conceivable. The above-mentioned surface treatment methods are described in “Characteristics and Application of Metal Soap” (Shobobo), “Printing Ink Technology” (CMC Publishing, 1984) and “Latest Pigment Application Technology” (CMC Publishing, 1986). Yes.
[0159]
The particle size of the pigment is preferably in the range of 0.01 μm to 10 μm, more preferably in the range of 0.05 μm to 1 μm, and particularly preferably in the range of 0.1 μm to 1 μm. When the particle diameter of the pigment is less than 0.01 μm, it is not preferable from the viewpoint of stability of the dispersion in the image forming layer coating solution, and when it exceeds 10 μm, it is not preferable from the viewpoint of uniformity of the image forming layer. As a method for dispersing the pigment, a known dispersion technique used in ink production, toner production, or the like can be used. Examples of the disperser include an ultrasonic disperser, a sand mill, an attritor, a pearl mill, a super mill, a ball mill, an impeller, a disperser, a KD mill, a colloid mill, a dynatron, a three-roll mill, and a pressure kneader. Details are described in "Latest Pigment Applied Technology" (CMC Publishing, 1986).
[0160]
As the dye, commercially available dyes and known dyes described in the literature (for example, “Dye Handbook” edited by Organic Synthetic Chemical Society, published in 1970) can be used. Specific examples include azo dyes, metal complex azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, and cyanine dyes. In the present invention, among these pigments or dyes, those that absorb infrared light or near infrared light are particularly preferable because they are suitable for use in lasers that emit infrared light or near infrared light.
[0161]
Carbon black is preferably used as the pigment that absorbs such infrared light or near infrared light. Examples of dyes that absorb infrared light or near infrared light include, for example, JP-A-58-125246, JP-A-59-84356, JP-A-59-202829, JP-A-60-78787, and the like. Cyanine dyes described in JP-A-58-173696, JP-A-58-181690, JP-A-58-194595, etc., JP-A-58-112793, Naphthoquinone dyes described in JP-A-58-224793, JP-A-59-48187, JP-A-59-73996, JP-A-60-52940, JP-A-60-63744, etc. And squarylium dyes described in No.-112792, etc., and cyanine dyes described in British Patent No. 434,875.
[0162]
Further, near-infrared absorption sensitizers described in US Pat. No. 5,156,938 are also preferably used as dyes, and substituted arylbenzo (thio) pyrylium described in US Pat. No. 3,881,924. Salts, trimethine thiapyrylium salts described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, 58-220143, 59-41363, 59 -84248, 59-84249, 59-146063, 59-146061, pyrylium compounds described in JP-A-59-216146, cyanine dyes, U.S. Pat. No. 4,283,475 The pentamethine thiopyrylium salt described in No. 5 and the pyrylium compounds disclosed in Japanese Patent Publication Nos. 5-13514 and 5-19702, Phosphorus Ltd. Epolight III-178, Epolight III-130, Epolight III-125 and the like are particularly preferably used.
[0163]
Another particularly preferable example of the dye is a near-infrared absorbing dye described in US Pat. No. 4,756,993 as formulas (I) and (II). These pigments or dyes are 0.01 to 50% by weight, preferably 0.1 to 10% by weight, particularly preferably 0.5 to 10% by weight, and pigments, based on the total solid content of the image forming layer. Particularly preferably, it can be added to the image forming layer at a ratio of 3.1 to 10% by weight. When the added amount of the pigment or dye is less than 0.01% by weight, the sensitivity is lowered, and when it exceeds 50% by weight, the uniformity of the image forming layer is lost and the durability of the image forming layer is deteriorated.
[0164]
Typical examples of the printing-out agent include a combination of a compound that releases an acid by heating by exposure (photoacid releasing agent) and an organic dye that can form a salt. Specifically, combinations of o-naphthoquinonediazide-4-sulfonic acid halides and salt-forming organic dyes described in JP-A-50-36209 and JP-A-53-8128, No. 36223, 54-74728, 60-3626, 61-143748, 61-151644 and 63-58440, and trihalomethyl compounds and salt-forming organic dyes Can be mentioned. Such trihalomethyl compounds include oxazole compounds and triazine compounds, both of which have excellent temporal stability and give clear printout images.
[0165]
As the image colorant, other dyes can be used in addition to the above-mentioned salt-forming organic dyes. Suitable dyes include oil-soluble dyes and basic dyes in addition to salt-forming organic dyes. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (oriental chemical industry) Manufactured by Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI42000), Methylene Blue (CI522015), and the like. Further, the dyes described in JP-A-62-293247 are particularly preferred as the image colorant. These dyes can be added to the image forming layer in a proportion of 0.01 to 10% by weight, preferably 0.1 to 3% by weight, based on the total solid content of the image forming layer.
[0166]
Plasticizers include butyl phthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, acrylic acid Or oligomers and polymers of methacrylic acid are used.
[0167]
The above-mentioned ablation positive type image forming layer, thermal positive type image forming layer and thermal negative type image forming layer made of an organic substance are usually prepared by dissolving each component in a solvent and applying it onto a metal layer having a hydrophilic surface. Can be manufactured.
Solvents used here include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxy Examples include ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyllactone, and toluene. It is not limited to.
[0168]
These solvents are used alone or in combination. The concentration of the above components (total solid content including additives) in the solvent is preferably 1 to 50% by weight. The coating amount (solid content) obtained after coating and drying varies depending on the use, but generally speaking, it is 0.5 to 5.0 g / m for a lithographic printing plate precursor.²Is preferred.
In the coating solution, a surfactant for improving the coating property, for example, a fluorine-based surfactant described in JP-A-62-170950 can be added. The addition amount is preferably 0.01 to 1% by weight, more preferably 0.05 to 0.5% by weight of the image forming layer.
Various methods can be used as the coating method, and examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.
[0169]
[Plate making method]
Next, a method for making a lithographic printing plate using a lithographic printing plate precursor will be described. The lithographic printing plate precursor having the above-described heat-sensitive image forming layer is, for example, a solid laser or semiconductor laser that directly performs image-like heat recording with a thermal recording head or the like, or emits infrared light having a wavelength of 760 to 1200 nm, or infrared light. The image is exposed by a method such as using a lamp or flash exposure of high-intensity ultraviolet light or visible light using a xenon discharge lamp or the like.
Image writing may be performed using either a surface exposure method or a scanning method. In the former case, there are an infrared irradiation method and a method in which heat is generated by light / heat conversion by irradiating the original plate with high-intensity short-time light from a xenon discharge lamp. When a surface exposure light source such as an infrared lamp is used, the preferred exposure varies depending on the illuminance, but usually the surface exposure intensity before modulation with a printing image is 0.1 to 10 J / cm.²Is preferably in the range of 0.3-1 J / cm²More preferably, it is the range.
[0170]
In the latter case, a method is used in which a laser light source containing a large amount of infrared components is used to modulate the laser beam with an image and scan the original. Examples of the laser light source include a semiconductor laser, a helium neon laser, a helium cadmium laser, and a YAG laser. It is preferable to irradiate a laser having a peak output of 1000 W, preferably 2000 W. In this case, the exposure amount is 0.1 to 10 J / cm at the surface exposure intensity before modulation with the printing image.²Is preferably in the range of 0.3-1 J / cm²More preferably, it is the range.
An image-exposed lithographic printing plate precursor can be developed after exposure and, if necessary, gummed, if necessary, and then the plate can be attached to a printing press for printing. Alternatively, printing can be performed by mounting a plate on a printing press immediately after exposure (without passing through a development step). In this case, the heating part or the exposed part is swollen by dampening water or the like, and the swollen part is removed at the initial stage of printing to form a planographic printing plate. That is, in the plate making method using the lithographic printing plate precursor according to the present invention, a lithographic printing plate can be made without any particular development treatment. The term “development” as used herein refers to development with water or a developer having a pH of 2 or more containing water as a main component.
[0171]
Whether development is performed or development processing is not performed, heat treatment is preferably performed after exposure from the viewpoint of improving sensitivity during recording. It is preferable to perform the conditions of heat processing within the range of 80-150 degreeC for 10 second-5 minutes. That is, by performing this heat treatment, the laser energy required for recording can be reduced during laser irradiation.
The lithographic printing plate precursor according to the present invention obtained by such treatment is developed or directly applied to an offset printing machine or the like without passing through a development step, and used for printing a large number of sheets.
[0172]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.
(Examples 1 to 6 and Comparative Examples 1 to 6: Thermal positive type image forming layer)
How to make a support
An aluminum plate having an alkali degreasing treatment with a thickness of 0.24 mm was used as a metal substrate, and the following treatments were performed in order.
[0173]
1) Mechanical surface roughening method
Polishing was performed at a rotational speed of 150 rpm while supplying a slurry-like abrasive (pamis having an average particle size of about 15 μm) with a 0.9 nylon brush.
2) Chemical dissolution treatment method i
The concentration of caustic soda was kept constant at 20 wt%, and the treatment time was adjusted so that Ra was 0.3 μm at a temperature of 40 ° C. Thereafter, the plate was washed with running water for 10 seconds, and then immersed in a sulfuric acid concentration of 120 g / liter, a liquid temperature of 50 ° C. for 10 seconds to perform a desmut treatment. The measured value of Ra was 0.3 ± 0.05 μm (standard deviation).
3) Electrolytic surface roughening treatment method
Using the power supply waveform disclosed in Japanese Patent Laid-Open No. 3-79799, the nitric acid concentration is set to 12 g / liter, the aluminum concentration is set to 6 g / liter, the liquid temperature is 60 ° C., and the current density on the anode side is 1.2 to 91 pits. Piece / mm²It was set to be in the range. Thereafter, it was washed with water. The number of pits is 70 ± 20 / mm as a result of SEM observation.²Met.
[0174]
4) Chemical dissolution treatment method ii
The concentration of caustic soda is fixed at 20 wt%, the treatment time is 1.3 g / m at a temperature of 40 ° C.²It was adjusted to become. Thereafter, the plate was washed with running water for 10 seconds, and then immersed in a sulfuric acid concentration of 120 g / liter, a liquid temperature of 50 ° C. for 10 seconds to perform a desmut treatment.
5) Anodizing method
4 is a device in which two devices of FIG. 4 of Japanese Patent Laid-Open No. 8-264118 are connected in series, and electricity is supplied using a DC power source under the anodizing conditions shown in Table 1 below to achieve a desired anodized film thickness. The time was adjusted so that a film was formed and washed with water. The measured value of Ra was 0.3 ± 0.05 μm (mean ± standard deviation).
6) Determination method of anodic oxide film thickness
The determination method of the processing time to obtain a desired anodic oxide film thickness was performed by a calibration curve method. For example, a calibration curve sample was prepared by changing the treatment time under each anodizing treatment condition shown in Table 1. Using a super high resolution SEM (Hitachi S-900), observe and measure the thickness of the anodic oxide film by bending a part of the calibration curve sample and using the ultra high resolution SEM (Hitachi S-900). did. Thus, a calibration curve showing the relationship between the treatment time and the anodic oxide film thickness was prepared, and the treatment time corresponding to the desired anodic oxide film thickness was determined from the calibration curve.
[0175]
7) Measuring method of pore diameter and maximum internal diameter of pore of anodized film
An ultrahigh-resolution SEM (Hitachi S-900) was used for the diameter of the pores in the pores of the anodized film. The surface was observed at a magnification of 150,000 times and an average value was used by randomly extracting 50 pores without performing a vapor deposition treatment for imparting conductivity at a relatively low acceleration voltage of 12 V. The standard deviation error was ± 10% or less.
The maximum internal diameter of the pores in the anodized film is made by bending the anodized aluminum and using a super high resolution SEM (Hitachi S-900) for the side surface (commonly called fracture surface) of the cracked part that occurs when the aluminum is bent. And observed. The inner maximum diameter portion of the pores on the fracture surface of the anodized film was observed at a magnification of 150,000 times without applying a vapor deposition treatment that imparts conductivity at a relatively low acceleration voltage of 12 V, and 50 pores Were randomly extracted and the average value was used. The standard deviation error was ± 10% or less.
[0176]
8) Sealing method
In Examples 1 to 4 and Comparative Example 1, sealing treatment was performed by allowing the anodized aluminum plate to pass through the hot water for a predetermined time shown in Table 1. Example 6 and Comparative Example 4 were 0.1 wt% NaF / 10 wt% NaH at 90-100 ° C.₂PO_FourSealing treatment was performed by allowing the aqueous solution (sealing agent A) to pass through for a predetermined time as shown in Table 1. In Example 5 and Comparative Examples 1, 2, 5 and 6, no sealing treatment was performed.
[0177]
9) Formation method of undercoat layer
No. 3 sodium silicate (Na) on the substrate (referred to as substrate [A]) after the sealing treatment.₂O: SiO₂= 1: 3) Treated with an aqueous solution having a sodium silicate concentration of 1 wt% at 20 ° C. for 10 seconds and washed with water to prepare a substrate [B]. The coating amount of sodium silicate was 6 mg / m as silicic acid as a result of quantitative analysis by a calibration curve method using a commercially available fluorescent X-ray analyzer.², 8mg / m as sodium silicate²Met. The sample for the calibration curve was prepared by diluting a proper amount of No. 3 sodium silicate with water over the entire surface of the X-ray irradiated area, dropping a predetermined volume, spreading and drying. Further, the substrate [B] was treated with an aqueous nitric acid solution having a pH of 3 at 20 ° C. for 10 seconds and washed with water to prepare a substrate [C]. A type A primer having the composition shown below was applied to the surface of the substrate [C] and dried at 80 ° C. for 15 seconds. The coating amount after drying is 15 mg / m²Met.
[0178]
[Type A primer]
The following compound 0.3g
Methanol 100 g
1 g of water
[0179]
Embedded image

[0180]
10) Method for forming image forming layer
Next, on the substrate processed as described above, the following photosensitive solution 1 is applied in an amount of 1.0 g / m.²After coating, the Wind Control was set to 7 with a TARFAI PERFECT OVENPH200 and dried at 140 ° C. for 50 seconds to obtain a lithographic printing plate precursor.
[0181]
[Photosensitive solution 1]
m, p-cresol novolak (m / p ratio = 6/4, 0.427 g
(Weight average molecular weight 3500, containing 0.5% by weight of unreacted cresol)
Siloxane structure-containing alkali-soluble resin (F-1) 0.047 g
2.37 g of specific copolymer 1 described in JP-A-11-288093
Cyanine dye A (the following structure) 0.155 g
2-Methoxy-4- (N-phenylamino) benzene 0.03 g
Diazonium hexafluorophosphate
Tetrahydrophthalic anhydride 0.19g
0.05 g of 6-hydroxy-β- counterion of ethyl violet
Naphthalene sulfonic acid
Fluorosurfactant (Megafac F-176PF, 0.035g
Dainippon Ink & Chemicals, Inc.)
Fluorosurfactant (Megafac MCF-312, 0.05g
Dainippon Ink & Chemicals, Inc.)
p-Toluenesulfonic acid 0.008g
Bis-p-hydroxyphenylsulfone 0.063 g
N-dodecyl stearyl acid 0.06g
γ-Butyllactone 13g
24g of methyl ethyl ketone
11 g of 1-methoxy-2-propanol
[0182]
[Synthesis of siloxane structure-containing alkali-soluble resin (F-1)]
Cresol novolak (m / p = 60/40, Mw = 5.2 × 10^Three) 120 g was dissolved in 400 ml of methanol, 5.4 g of sodium methoxide was added, and the mixture was stirred for 30 minutes. Methanol was distilled off under reduced pressure, 400 ml of tetrahydrofuran was added, and the solvent was replaced. 17 g of epoxy-type terminal reactive silicone MCR-E11 (manufactured by Chisso Corporation) was added, and the mixture was heated to reflux for 6 hours. The reaction solution was cooled to room temperature, poured into 8000 ml of water, and the separated product was collected by filtration, washed with water, and dried to obtain 132 g of a siloxane structure-containing alkali-soluble resin (F-1).
[0183]
Embedded image

[0184]
11) Laser irradiation conditions
Commercial exposure was performed using a trend setter 3244 manufactured by Creo. The exposure conditions are: output 0.5 W, wavelength 830 nm, beam diameter 17 μm (1 / e²), The main scanning speed was set to 5 m / S.
12) Clear sensitivity evaluation method
The plate surface of the lithographic printing plate precursor was subjected to full exposure by changing the laser irradiation output, and developed by Fuji Photo Film Co., Ltd. Developer DT-1 (diluted 1: 8) and Fuji Photo Film Co., Ltd. Finisher FP2W Using a PS processor 900H manufactured by Fuji Photo Film Co., Ltd. (diluted 1: 1), the film was developed at a liquid temperature of 30 ° C. and a development time of 12 seconds. The electric conductivity of the developer at this time was 45 mS / cm. Change the density of the developed lithographic printing plate with a Macbeth densitometer (setting; blue), the change point of the correlation diagram when the Macbeth density is on the vertical axis and the laser output is on the horizontal axis (the image forming layer is completely Sensitivity evaluation was performed considering that the color of the support was lost) and the clear sensitivity. Note that the sensitivity of Comparative Example 2 is the standard (100 mJ / cm²), The sensitivity of each of Examples 1 to 6, Comparative Example 1, and Comparative Examples 3 to 6 was determined.
[0185]
13) Printing evaluation method
The lithographic printing plate precursor subjected to image exposure by laser irradiation as described above was developed with a developer DT-1 (diluted 1: 8) manufactured by Fuji Photo Film Co., Ltd. and finisher FP2W manufactured by Fuji Photo Film Co., Ltd. ( The film was developed using a PS processor 900H manufactured by Fuji Photo Film Co., Ltd., which had been diluted 1: 1, at a liquid temperature of 30 ° C. and a development time of 12 seconds. The electric conductivity of the developer at this time was 45 mS / cm. After development, the obtained lithographic printing plate was mounted on a printing machine for printing. As a printing machine, Harris chrysanthemum half-monochrome machine (manufactured by Harris Co., Ltd.) is used, Geos ink (manufactured by Dainippon Ink & Chemicals, Inc.) as ink, and dampening water EU-3 (Fuji Photo) as dampening water. A film (manufactured by Co., Ltd.) diluted 1: 100 with water was used to print on fine paper using a mixture of 90 vol% and isopropanol 10 vol%.
[0186]
14) Evaluation method of residual color and residual film
For the residual color, the amount of the dye remaining in the non-image area after development was relatively evaluated with a commercially available spectrophotometer (measurement wavelength: 830 nm).
The remaining film was subjected to relative evaluation with a commercially available spectrophotometer (measurement wavelength: 280 nm) after development, in the amount of the binder remaining in the non-image area.
15) Dirt performance evaluation method
After printing 500 sheets from the start of printing, the printing machine was temporarily stopped, the ink in the blanket part of the printing machine was copied with a PET tape manufactured by Nitto Denko, and the degree of smearing with the ink in the non-image area was visually evaluated.
16) Printing durability evaluation method
The point in time when the stain performance became Δ or less was determined to be finished, and the number of printed sheets at that point was taken as the number of finished sheets.
[0187]
Each result is summarized in Table 1 below.
[0188]
[Table 1]

[0189]
Residual color / residual film: ◎; not detected, ○: detected a little, △; detected,
×: Detected considerably, XX: Detected entirely
Dirt: ◎: Not dirty at all, ○: Slightly dirty, △: Dirty, ×: Very dirty,
Xx: The whole surface gets dirty
Printing durability (number of completed sheets): ◎; 30,000 or more, ○; less than 30,000, 10,000 or more,
Δ: Less than 10,000 sheets 3,000 sheets or more, ×: Less than 3,000 sheets 100 sheets,
XX: 100 sheets or less
[0190]
(Examples 7 to 12 and Comparative Examples 7 to 12: Thermal negative type image forming layer)
The process up to the sealing treatment method was as shown in Table 2 below in accordance with Examples 1 to 6 and Comparative Examples 1 to 6.
Method for forming image forming layer
The following image forming layer coating solution (formulation B) was applied onto the substrate with a coating bar, and dried in a 100 ° C. oven for 1 minute. As a result of measuring and averaging the thickness of the coating solution before and after application with a micrometer at 10 points, the average thickness of the thermal negative image forming layer (prescription B) was 1.5 μm and the standard deviation was 0.8 μm. The thickness calculated from the change in weight before and after application of the coating solution and the specific gravity was 1.7 μm. This was used as a lithographic printing plate precursor.
[0191]
Image forming layer coating solution (Prescription B)
・ 0.2g of the following compounds that generate acid by light or heat
-0.7 g of the following cross-linking agent (phenol derivative) that cross-links with acid
・ Binder (1.5g of Polyvinylphenol manufactured by Maruzen Petrochemical Co., Ltd.)
"Marcalinker MS-4P"
・ Infrared absorber NK-3508 (trade name) 0.15 g
(Nippon Sensitive Dye Research Institute)
・ Other additives
Victoria Pure Blue BO (C.I. 44040) 0.05 g
Fluorosurfactant (Megafac F-177, 0.06g
Dainippon Ink & Chemicals, Inc.)
·solvent
Methyl ethyl ketone 15g
1-methoxy-2-propanol 5g
7g methyl alcohol
[0192]
Embedded image

[0193]
Laser irradiation conditions and development conditions
Each of the obtained lithographic printing plate precursors was exposed to a solid-state laser continuous wave YAG laser (maximum light output 0.724 W) emitting infrared light having a wavelength of 1064 nm. Scanning speed 120cm / s, 1 / e²Beam diameter: D = 35 μm (Because the beam profile was a good Gaussian distribution, the Gaussian distribution was approximated and 1 / e of the peak maximum intensity²The position of the light output was taken as the beam diameter. ) And then heat-treated in an oven set at 140 ° C. for 45 seconds. Thereafter, the heat-treated sample was developed using a commercially available automatic processor PS-900NP (manufactured by Fuji Photo Film Co., Ltd.) having an immersion type developing tank. The PS-900NP development tank was charged with 20 liters of an alkali development solution (pH of about 13) having the following composition, and the temperature of the development solution was kept at 30 ° C.
The second bath of PS-900NP is charged with 8 liters of tap water, and the third bath is charged with 8 liters of finishing gum solution diluted with FP2W (Fuji Photo Film Co., Ltd.): Water = 1: 1. It is.
[0194]
Composition of alkaline developer
・ D-Sorbit 2.5% by weight
-Sodium hydroxide 0.85% by weight
・ Diethylenetriaminepenter (methylenephosphonic acid) 0.05% by weight
5Na salt
・ Water 96.6% by weight
[0195]
The clear sensitivity and the print evaluation method were the same as those in Examples 1 to 6 and Comparative Examples 1 to 6, except that the development conditions and the like were as described above. In the clear sensitivity, the sensitivity of Comparative Example 8 is used as a reference (100 mJ / cm²), The sensitivities of Examples 7 to 12, Comparative Example 7 and Comparative Examples 9 to 12 were determined. The remaining color, remaining film performance, stain performance, and printing durability evaluation method were also performed in the same manner as in Examples 1 to 6 and Comparative Examples 1 to 6.
[0196]
The results are shown in Table 2 below.
[Table 2]

[0197]
Residual color / residual film: ◎; not detected, ○: detected a little, △; detected,
×: Detected considerably, XX: Detected entirely
Dirt: ◎: Not dirty at all, ○: Slightly dirty, △: Dirty, ×: Very dirty,
Xx: The whole surface gets dirty
Printing durability (number of completed sheets): ◎; 30,000 or more, ○; less than 30,000, 10,000 or more,
Δ: Less than 10,000 sheets 3,000 sheets or more, ×: Less than 3,000 sheets 100 sheets,
XX: 100 sheets or less
[0198]
(Examples 13 to 18 and Comparative Examples 13 to 18: Ablation positive type image forming layer)
According to Examples 1-6 and Comparative Examples 1-6, it was as Table 3 below until the sealing treatment method.
[0199]
Method for forming image forming layer
The sealing treatment was performed, and an ablation type image forming layer coating solution was applied and dried on the support. That is, the following image forming layer coating solution (formulation C) was coated with a coating bar and dried in a 120 ° C. oven for 1 minute. As a result of measuring and averaging the thickness of the image forming layer (prescription C) before and after application with a micrometer at 10 points, the average thickness of the image forming layer (prescription C) was 1 μm ± standard deviation 0.8 μm. The thickness calculated from the weight change and the specific gravity before and after forming the coating film of the image forming layer was 1 μm.
Image forming layer coating solution (formulation C)
Behenic acid: 5 mg, PMMA: 41 mg (Aldrich, average molecular weight 996000 (GPC)), Cyabsorb IR-165 (American Cynamid): 8 mg was dissolved in 13 cc chloroform to prepare an image forming layer coating solution (formulation C).
[0200]
Laser exposure conditions
Continuous wave YAG laser (wavelength 1,064 μm), laser beam maximum output 0.724 W, scanning speed 120 cm / s, 1 / e²Beam diameter 35 μm (Because the beam profile was a good Gaussian distribution, the Gaussian distribution was approximated and 1 / e of the peak maximum intensity²The position of the light output was taken as the beam diameter. )
The clear sensitivity and the print evaluation method were the same as those in Examples 1 to 6 and Comparative Examples 1 to 6, except that the development process was not performed. In the clear sensitivity, the sensitivity of Comparative Example 14 is used as a reference (100 mJ / cm²), The sensitivities of Examples 13 to 18, Comparative Example 13 and Comparative Examples 15 to 18 were determined. The remaining color, remaining film performance, stain performance, and printing durability evaluation method were also performed in the same manner as in Examples 1 to 6 and Comparative Examples 1 to 6.
[0201]
The results are shown in Table 3 below.
[0202]
[Table 3]

[0203]
Residual color / residual film: ◎; not detected, ○: detected a little, △; detected,
×: Detected considerably, XX: Detected entirely
Dirt: ◎: Not dirty at all, ○: Slightly dirty, △: Dirty, ×: Very dirty,
Xx: The whole surface gets dirty
Printing durability (number of completed sheets): ◎; 30,000 or more, ○; less than 30,000, 10,000 or more,
Δ: Less than 10,000 sheets 3,000 sheets or more, ×: Less than 3,000 sheets 100 sheets,
XX: 100 sheets or less
[0204]
(Examples 19 to 29 and Comparative Examples 19 to 26: Ablation positive type image forming layer)
  In addition, Example 21 and Example 29 shall be read as Reference Example 21 and Reference Example 29, respectively.
  Support having an anodic oxide film having the properties described in Table 4 below (surface pore average pore diameter, internal pore maximum diameter, surface mouth film thickness, internal pore film thickness, surface mouth pore density, pore porosity) An ablation positive type image forming layer similar to that of Examples 13 to 18 was provided on the body to obtain a lithographic printing plate precursor.
  The on-press developability, scratch resistance, sensitivity and printing durability of these lithographic printing plate precursors were evaluated.
  The printing durability was evaluated in the same manner as in Examples 1 to 18, and the on-press developability, scratch resistance and sensitivity were evaluated by the following methods. The evaluation results are shown in Table 4 below.
[0205]
<On-press developability evaluation method>
Printing machine: Harris chrysanthemum half-color machine (manufactured by Harris Corporation)
Ink: Geos Beni (Dainippon Ink Chemical Co., Ltd.)
The number of printed sheets from the start of printing until a normal printed matter was obtained was examined.
[0206]
○: 1-50
○ △: 51-100 sheets
Δ: 101-200 sheets
×: 201 or more
[0207]
<Scratch resistance test>
Scratch testing machine: HEIDON Scratching Intensity TESTER HEIDON-18
A diamond needle was used, and the level was evaluated by comprehensive evaluation of the difficulty of scratching when the load was changed from 50 to 400 g.
[0208]
○: Overall evaluation scratch resistance very good
Δ: Good (no problem level)
×: Impossible
[0209]
<Sensitivity = evaluation method for clear sensitivity>
The entire surface of the original plate for lithographic printing plates is exposed by changing the laser output and mounted on a printing machine (Harris Chrysanthemum Monochrome Machine (made by Harris Corporation)), and the printing machine is operated without using ink. After a minute, the change in density of the planographic printing plate was measured with a Macbeth densitometer (setting: blue). Sensitivity evaluation was performed considering that the color of the support was completely eliminated and the color of the support was considered clear. The sensitivity of Comparative Example 20 is the standard (100 mJ / cm²), The sensitivities of Examples 19 to 29, Comparative Example 19 and Comparative Examples 21 to 26 were obtained.
[0210]
[Table 4]

[0211]
【The invention's effect】
  The lithographic printing plate precursor according to the present invention has a surface diameter of 0 to 30 nm and a maximum internal diameter on a metal support.40By having an anodic oxide film having a pore of ˜300 nm, it was possible to improve the residual color performance and the residual film performance while maintaining the sensitivity, dirt and printing durability.
  Further, the thickness of the surface mouth portion of the anodized film having a pore diameter of 0 to 30 nm is 10 to 500 nm, and the pore diameter is40The thickness of the internal maximum diameter portion of ˜300 nm is 100 to 2000 nm, and the pore density of the surface portion of the anodized film is 2500 / μm.²Hereinafter, by setting the porosity of the anodized film to 20 to 70%, scratch resistance can be improved.

Claims (8)

An anodized film having a pore having a surface mouth diameter of 0 to 30 nm and an internal maximum diameter of 40 to 300 nm on a metal support, and an image forming layer containing a photothermal conversion agent on the anodized film An original plate for a lithographic printing plate, comprising:   2. The lithographic printing plate precursor as claimed in claim 1, wherein the pores of the pores of the anodized film are subjected to sealing treatment to reduce the diameter of the surface orifices. The thickness of the surface mouth part of the pore diameter of 0 to 30 nm of the anodized film is 10 to 500 nm, and the thickness of the internal maximum diameter part of the pore diameter of 40 to 300 nm is 100 to 2000 nm. Item 2. A lithographic printing plate precursor as described in Item 1. ^2. The lithographic printing plate precursor as claimed in claim 1, wherein the pore density of the surface portion of the anodized film is 2500 / μm ² or less .   2. The lithographic plate according to claim 1, wherein the anodic oxide film is formed by anodizing with an electrolyte containing sulfuric acid and subsequently anodizing with an electrolyte containing phosphoric acid. Original plate for printing plate. The lithographic printing plate precursor as claimed in claim 1, wherein the image forming layer is an ablation positive image forming layer, a thermal positive image forming layer, a thermal negative image forming layer or an on-press developing thermal negative image forming layer. An image forming layer containing a photothermal conversion agent is formed on the anodized film after forming an anodized film having a pore with a surface opening diameter of 0 to 30 nm and an internal maximum diameter of 40 to 300 nm on a metal support. A method for producing an original plate for a lithographic printing plate to be formed, wherein a sealing treatment is performed on a surface mouth portion of a pore of an anodized film after anodizing treatment, and the diameter of the surface mouth portion is reduced. A method for producing a lithographic printing plate precursor. An image forming layer containing a photothermal conversion agent is formed on the anodized film after forming an anodized film having a pore with a surface opening diameter of 0 to 30 nm and an internal maximum diameter of 40 to 300 nm on a metal support. A method for producing a lithographic printing plate precursor to be formed, wherein the anodizing treatment is performed with an electrolytic solution containing sulfuric acid, followed by an electrolytic solution containing phosphoric acid. Method.