JP3790319B2 - Support for imaging materials - Google Patents

Description

【００３５】
数式１において、Ｗｘは試料面域のＸ軸方向（抄紙方向）の長さを表わし、Ｗｙは試料面域のＹ軸方向（抄紙方向と垂直な方向）の長さを表わし、Ｓａは試料面域の面積を表す。
【００３６】
本発明の実施に好ましく用いられる、中心面平均粗さＳＲａが１.５０μm以下の基紙を製造する方法としては、具体的には、前記（段落００２７）したように適切な繊維長及び濾水度になるように叩解されたパルプを用い、また湿紙の乾燥途中で多段の緊度プレスを行い、更に基紙を抄造後マシンカレンダー、スーパーカレンダー、熱カレンダー等を用いて少なくとも２系列以上のカレンダー処理、例えば基紙に第１系列のカレンダー処理としてマシンカレンダー処理あるいは／及び熱マシンカレンダー処理を行い、その後第２系列以降のカレンダー処理として必要に応じて更にマシンカレンダー処理を行った後特開平4-110939号公報に記載もしくは例示の熱ソフトカレンダー処理を行って、中心面平均粗さＳＲａが１.５０μm以下の基紙を製造することが出来る。また、基紙中あるいは基紙上に各種の水溶性ポリマーもしくは親水性コロイドあるいはポリマーラテックスをサイズプレスもしくはタブサイズプレスあるいはブレード塗工、エアーナイフ塗工などの塗工によって固形塗布量として１.０g/m２以上、特に２.２g/m２以上含有あるいは塗設せしめるのが好ましい。
【００３７】
本発明の実施に用いられる基紙の密度としては、灰分を除いて計算して０.８０g/cm³〜１.１５g/cm³の範囲が好ましく、０.８５g/cm³〜１.０５g/cm³の範囲が更に好ましいが、本発明は、これらに限定されるものではない。また、本発明の実施に用いられる基紙の厚味に関しては、特に期限はないが、その坪量は４０g/m²〜２５０g/m²のものが有用であり、７０g/m²〜２２０g/m²のものが好ましい。
【００３８】
本発明における画像材料用支持体の基紙の画像形成層を設ける側（表側）は、フィルム形成能ある樹脂を含む樹脂層で被覆される。また、基紙の裏側は、フィルム形成能ある樹脂を含む樹脂層で被覆されるのが好ましい。それらのフィルム形成能ある樹脂としてはポリオレフィン樹脂、ポリカーボネート樹脂、ポリエステル樹脂、ポリアミド樹脂及びそれらの混合物などの熱可塑性樹脂が好ましく、中でも溶融押し出しコーティング性の点から前記したポリオレフィン樹脂あるいは／及びポリエステル樹脂が更に好ましく、ポリエチレン系樹脂が特に好ましい。また、特公昭60-17104号公報に記載もしくは例示の電子線硬化樹脂から成る樹脂層で被覆してもよい。
【００３９】
本発明の実施に好ましく用いられる表樹脂層用及び裏樹脂層用のポリエチレン系樹脂としては、低密度ポリエチレン樹脂、中密度ポリエチレン樹脂、高密度ポリエチレン樹脂、直鎖状低密度ポリエチレン樹脂、超低密度ポリエチレン樹脂、エチレンとプロビレン、ブチレン等のα―オレフィンとの共重合体、エチレンとアクリル酸、アクリル酸エチルエステル、無水マイレン酸等の共重合体またはグラフト共重合体である、所謂カルボキシ変性ポリエチレン樹脂等、またオートクレーブ型反応器、チューブラー型反応器等を用いた高圧ラジカル重合法によるポリエチレン系樹脂、メタロセン重合触媒を用いて重合製造したポリエチレン系樹脂、チーグラー法、フィリップス法等を用いた、メタロセン以外の金属触媒を用いて重合製造したポリエチレン系樹脂及びこれらの混合物をあげることが出来る。それらのポリエチレン系樹脂及び混合物としては、各種の密度、メルトフローレート（以下、ＪＩＳ Ｋ ６７６０で規定されるメルトフローレートのことを単にＭＦＲと略す）、分子量、分子量分布のものを使用できるが、通常、樹脂層を構成する樹脂成分（混合物である場合には混合物として）の密度が０.９０〜０.９７g/cm³の範囲、ＭＦＲが０.１g/10分〜５０g/10分、好ましくは、ＭＦＲが０.３g/10分〜４０g/10分の範囲のものを単独にあるいは混合して有利に使用できる。
【００４０】
本発明の実施に表樹脂層用に好ましく用いられる高圧法により重合製造したポリエチレン系樹脂としては、オートクレーブ型反応器、チューブラー型反応器などを用いた高圧製造法による長鎖分枝を有する各種のポリエチレン系樹脂である。それらの高圧法により重合製造したポリエチレン系樹脂としては、低密度ポリエチレン樹脂、中密度ポリエチレン樹脂、エチレンを主成分とするプロピレン、ブチレンなどのα−オレフィンとの共重合体、カルボキシ変性ポリエチレン樹脂など及びこれらの混合物であり、各種の密度、ＭＦＲ、分子量、分子量分布のものを使用できるが、通常、密度が０.９０〜０.９５g/cm³の範囲、ＭＦＲが０.１〜５０g/１０分、好ましくはＭＦＲが０.４〜５０g/１０分の範囲のものを単独にあるいは二種以上混合して使用できる。
【００４１】
本発明の実施に表樹脂層用に特に好ましく用いられるメタロセン重合触媒を用いて重合製造したポリエチレン系樹脂としては、特表平3-502710号公報、特開昭60-35006号公報、特表昭63-501369号公報、特開平3-234717号公報、特開平3-234718号公報などに記載もしくは開示されている如く、ジルコニウム系またはハフニウム系などのメタロセンと、好ましくはメチルアルミノキサンなどとを組み合わせて触媒活性を高めたものを重合触媒として用いて重合製造されたものである。それらのメタロセン重合触媒を用いて重合製造したポリエチレン系樹脂としては、超低密度ポリエチレン樹脂、低密度ポリエチレン樹脂、中密度ポリエチレン樹脂、高密度ポリエチレン樹脂、直鎖状低密度ポリエチレン樹脂、エチレンを主成分とするプロピレン、ブチレンなどのα−オレフィンとの共重合体、カルボキシ変性ポリエチレン樹脂など及びこれらの混合物であり、各種の密度、ＭＦＲ、分子量、分子量分布のものを使用できるが、通常、密度が０.８７〜０.９７g/cm³の範囲、ＭＦＲが０.０５〜５００g/１０分、好ましくは０.０８〜３００g/１０分の範囲のものを単独にあるいは二種以上混合して使用できる。
【００４２】
本発明の実施に表樹脂層用に特に好ましく用いられるメタロセン重合触媒以外の金属重合触媒を用いて重合製造したポリエチレン系樹脂としては、例えばチーグラー法、フィリップス法などを用いて重合製造した各種のポリエチレン系樹脂を挙げることができる。それらの金属メタロセン重合触媒以外の金属重合触媒を用いて重合製造したポリエチレン系樹脂としては、超低密度ポリエチレン樹脂、低密度ポリエチレン樹脂、中密度ポリエチレン樹脂、高密度ポリエチレン樹脂、直鎖状低密度ポリエチレン樹脂、エチレンを主成分とするプロピレン、ブチレンなどのα−オレフィンとの共重合体、あるいはカルボキシ変性ポリエチレン樹脂など及びこれらの混合物であり、各種の密度、ＭＦＲ、分子量、分子量分布のものを使用できるが、通常、密度が０.８７〜０.９７g/cm³の範囲、ＭＦＲが０.０５〜５００g/１０分、好ましくは０.０８〜３００g/１０分の範囲のものを単独に或いは二種以上混合して使用できる。
【００４３】
本発明の実施に用いられるポリエステル系樹脂としては、ポリエチレンテレフタレート樹脂、ポリブチレンテレフタレート樹脂、ポリエステル系生分解性樹脂及びこれらの混合物またはそれらとポリエチレン系樹脂との混合物であり、各種の密度、極限粘度[η]のものを使用できる。具体的な代表例としては、三菱化成株式会社製ポリエステル樹脂（商品名：ＮＯＶＡＰＥＸ ＨＳ００４、融点２３５℃、密度１.３３g/cm³、極限粘度[η]０.７３dl/g）を挙げることができる。また、ポリエステル樹脂とポリエチレン系樹脂との混合物を有利に用いることができる。例えば、共重合ポリエチレンテレフタレート樹脂とマレイン酸でグラフト変性された共重合ポリエチレン樹脂（融点７４℃）との混合物（三菱化成株式会社製、融点２２４℃）を挙げることができる。
また、本発明の実施に用いられるポリカーボネート系樹脂としては、各種のグレードのものを使用できるが、具体的な代表例としては、三菱化成株式会社製ポリカーボネート系樹脂（商品名：ＮＯＶＡＲＥＸ ７０２２Ａ、密度１.２０g/cm³、ＭＦＲ１２〜１６g/１０分、軟化点１６０℃〜１９０℃）を挙げることができる。
【００４４】
本発明の実施に有利に用いられる裏樹脂層用のポリエチレン樹脂としては、ＭＦＲが１０g/10分〜４０g/10分、好ましくは１０g/10分〜３０g/10分、密度が０.９６０g/cm³以上である高密度ポリエチレン系樹脂９０重量部〜６５重量部とＭＦＲが０.２g/10分〜３g/10分、好ましくは、０.２g/10分〜１.５g/10分、密度が０.９３５g/cm³以下である低密度ポリエチレン樹脂または中密度ポリエチレン樹脂１０重量部〜３５重量部とを予め溶融・混合したコンパウンド樹脂組成物が好ましい。また、低密度ポリエチレン樹脂または中密度ポリエチレン樹脂の分子量分布としては、分子量５０万以上の分率が１０重量%以上のものが好ましく、１２重量%以上のものが特に好ましい。該樹脂の分子量５０万以上の分率が１０重量%より少ないと成形加工性、特にネックインが大きくなって好ましくない。ここで、分子量の測定はウォーターズ社製１５０−Ｃ（カラム：東ソー社製ＧＭＨ−ＸＬ ＨＴ ８mmφ×３０cm×３本、溶媒：１，２，４−トリクロロベンゼン、温度：１３５℃、流量：１ml/min）を用いるＧＰＣ法により行った。
【００４５】
本発明の実施に用いられる裏樹脂層用のポリエチレン系樹脂としては、予め溶融・混合して調製したコンパウンド樹脂が好ましい。低密度ポリエチレン樹脂あるいは中密度ポリエチレン樹脂と高密度ポリエチレン樹脂とを予め溶融・混合してコンパウンド樹脂を調製する方法としては、単純溶融混合法、多段溶融混合法等を用いることができる。例えば、押し出し機、二軸押し出し機、加熱ロール練り機、バンバリーミキサー、加圧ニーダー等を用いて、所定量の低密度あるいは中密度ポリエチレン樹脂と高密度ポリエチレン樹脂、更に必要に応じて酸化防止剤、滑剤等の各種の添加剤を加えて溶融・混合した後、その混合物をペレット化する方法が有利に用いられる。
【００４６】
本発明における画像材料用支持体は、表樹脂層中及び裏樹脂層中のフィルム形成能ある樹脂が熱可塑性樹脂、好ましくはポリオレフィン樹脂、特に好ましくはポリエチレン系樹脂の場合には、表樹脂層用及び裏樹脂層用の樹脂組成物を溶融押し出し機を用いて、走行する基紙上にそのスリットダイからフィルム状に流延して被覆する、いわゆる溶融押し出しコーティング方式によって製造される。通常は、走行する基紙上に溶融押し出し機を用いて、そのスリットダイから溶融した樹脂組成物をフィルム状に押し出し、流延して被覆し、加圧ロールと冷却ロールとの間で圧着し、冷却ロールから剥離されるという一連の工程で生産される。
【００４７】
本発明における画像材料用支持体の表樹脂層としては、２層構成あるいはそれ以上の多層構成にすることによって、ノンドライ広葉樹漂白クラフトパルプを含む基紙との併用による相乗効果によって、本発明の効果が極めて顕著に発揮されることを見い出した。即ち、本発明における画像材料用支持体の表樹脂層を２層構成あるいはそれ以上の多層構成にすることによって、該支持体を有する画像材料及びそのプリントの見た目の光沢感を極めて顕著に改良出来ること、かつ支持体製造時の冷却ロールからの剥離性を顕著に改良出来ること、従って剥離むらの発生を無くすことが出来ること、それ故に画像材料用支持体を高速かつ安定生産できることを見い出した。
【００４８】
本発明における特に好ましい画像材料用支持体は、表樹脂層が２層あるいはそれ以上の多層構成のものであるが、２層構成のものが本発明の目的を効率的に達成する上で好ましい。また、表樹脂層が２層あるいはそれ以上の多層構成である画像材料用支持体としては、溶融押し出しコーティング方式によって製造されるものが好ましい。その製造に際し、２層あるいはそれ以上の多層の樹脂層が多層同時に押し出しコーティングされる、所謂共押し出しコーティング方式を用いてもよいし、少なくとも最下層から成る樹脂層、その後に少なくとも最上層から成る樹脂層が、順に別個のステーションで逐次に溶融押し出しコーティングされる、所謂逐次押し出しコーティング方式を用いてもよい。本発明においては、逐次押し出しコーティング方式を用いて製造される画像材料用支持体が特に好ましい。
【００４９】
また、溶融押し出しコーティングの際、スリットダイとしてはＴ型ダイ、Ｌ型ダイ、フィッシュテイル型ダイのフラットダイが好ましく、スリット開口径は０.１mm及至２mmであることが望ましい。また、多層共押し出しダイのタイプとしては、フィードブロックタイプ、マルチマニホールドタイプ、マルチスロットタイプ等のいずれタイプでもよい。また、溶融フィルムの温度は、２８０℃及至３４０℃であることが好ましく、その際最上層用の樹脂組成物とそれより下側の樹脂層を構成する樹脂組成物の温度差をつけてもよい。例えば、最上層用の樹脂組成物の温度をそれより下側の樹脂層を構成する樹脂組成物の温度より５〜１０℃低くして、樹脂層の冷却ロールからの剥離性の向上を図ることが出来る。
【００５０】
表樹脂層が多層構成である、本発明における特に好ましい画像材料用支持体の樹脂層としては、最上層の樹脂層（以下、単に最上層と略することがある）とそれより下側の樹脂層（以下、単に下側樹脂層と略することがある）とは、同じ物性、組成であってもよいし、異なっていてもよい。最上層及び下側樹脂層に好ましく用いられるポリエチレン系樹脂としては、前記したような各種の密度、ＭＦＲ、分子量、分子量分布等のものを単独にまたは混合して使用出来るし、それらの物性が同じものであってもよいし、異なっていてもよい。
【００５１】
例えば、最上層中のポリエチレン系樹脂として、そのＭＦＲ（二種以上含有している場合には、混合物としてのＭＦＲ、以下同意義である）が下側樹脂層中のポリエチレン系樹脂のＭＦＲ（二種以上含有している場合には、混合物としてのＭＦＲ、以下同意義である）より高いもの、低いものあるいは同じものを使用することが出来る。例えば、最上層中のポリエチレン系樹脂のとして、ＭＦＲが５g/１０分〜２０g/１０分のもの、下側樹脂層中のポリエチレン系樹脂として、ＭＦＲが２g/１０分〜１０g/１０分のものを使用出来るし、一方最上層中のポリエチレン系樹脂として、ＭＦＲが２g/１０分〜１０g/１０分のもの、下側樹脂層中のポリエチレン系樹脂として、ＭＦＲが５g/１０分〜２０g/１０分のものを使用出来るし、また、ＭＦＲが同じであるものを使用出来る。
【００５２】
また、最上層中のポリエチレン系樹脂として、その密度（二種以上含有している場合には、混合物としての密度、以下同意義である）が下側樹脂層中のポリエチレン系樹脂の密度（二種以上含有している場合には、混合物としての密度、以下同意義である）より高いもの、低いものあるいは同じものを使用することが出来る。例えば、最上層中のポリエチレン系樹脂として、密度が０.９２５g/cm³〜０.９７０g/cm³のもの、下側樹脂層中のポリエチレン系樹脂として、密度が０.８７０g/cm³〜０.９２５g/cm³のものを使用出来るし、一方最上層中のポリエチレン系樹脂として、密度が０.８７０g/cm³〜０.９２５g/cm³のもの、下側樹脂層中のポリエチレン系樹脂として、密度が０.９２５g/cm³〜０.９７０g/cm³のものを使用出来るし、また密度が同じであるものを使用出来る。
【００５３】
また、最上層中のポリエチレン系樹脂として、その融点が下側樹脂層中のポリエチレン系樹脂の融点より高いもの、低いものあるいは同じものを少なくとも１種使用出来る。例えば、最上層中のポリエチレン系樹脂として、融点が１１５℃以上のもの、下側樹脂層中のポリエチレン系樹脂として、融点が１１５℃未満のものを使用出来るし、一方最上層中のポリエチレン系樹脂として、融点が１１５℃未満のもの、下側樹脂層中のポリエチレン系樹脂として、融点が１１５℃以上のものと使用出来るし、また、融点が同じであるものを使用出来る。
【００５４】
本発明における画像材料用支持体の特に好ましい多層構成の樹脂層としては、本発明の効果、即ち該支持体を有する画像材料及びそのプリントの見た目の光沢感の改良効果及び剥離性の改良効果を極めて顕著に発揮出来るという観点から、最上層中のポリエチレン系樹脂としては、その密度が、下側樹脂層中のポリエチレン系樹脂の密度より高いものを少なくとも１種使用するか、または融点が、下側樹脂層中のポリエチレン系樹脂の融点より高いものを少なくとも１種使用するか、あるいは密度、融点共が下側樹脂層中のポリエチレン樹脂のそれらより高いものを少なくとも１種使用している多層構成の樹脂層が特に好ましい。
【００５５】
本発明における画像材料用支持体の表樹脂層中及び必要に応じて裏樹脂層中には、各種の添加剤を含有せしめることが出来る。支持体の白色度及び画像の鮮鋭度を改良する目的で、特公昭60-3430号公報、特公昭63-11655号公報、特公平1-38291号公報、特公平1-38292号公報、特開平1-105245号公報等に記載もしくは例示の二酸化チタン顔料を含有せしめるのが好ましい。また、二酸化チタンの他に酸化亜鉛、タルク、炭酸カルシウム等の白色顔料、離型剤として、ステアリン酸アミド、アラキジン酸アミド等の脂肪酸アミド、顔料の分散剤及び離型剤として、ステアリン酸亜鉛、ステアリン酸カルシウム、ステアリン酸アルミニウム、ステアリン酸マグネシウム、パルミチン酸亜鉛、ミリスチン酸亜鉛、パルミチン酸カルシウム等の脂肪酸金属塩、特開平1-105245号公報に記載もしくは例示のヒンダードフェノール、ヒンダードアミン、リン系、硫黄系等の各種酸化防止剤、コバルトブルー、群青、セリアンブルー、フタロシアニンブルー等のブルー系の顔料や染料、コバルトバイオレット、ファストバイオレット、マンガンバイオレット等のマゼンタ系の顔料や染料、特開平2-254440号公報に記載もしくは例示の蛍光増白剤、紫外線吸収剤等の各種の添加剤を適宜組み合わせて含有せしめることが出来る。それらの添加剤は、樹脂のマスターバッチあるいはコンパウンドとして含有せしめるのが好ましい。また、プリントの鮮鋭度または白色度あるいは画像材料用支持体の耐熱性、耐光性または離型性の効果的な向上等の点から、酸化チタン等の白色顔料及び蛍光増白剤、着色顔料や着色染料あるいは酸化防止剤、紫外線吸収剤または離型剤等その他の添加剤を下側樹脂層中より最上層中に高濃度に含有せしめるのが好ましい。特に、二酸化チタン顔料の最上層中の含有割合（最上層中の重量に対する割合として）を、７重量%以上、更に９重量%以上、なお更に１２重量%以上、特に１５重量%以上にすることが好ましい。
【００５６】
本発明の実施に当り、表・裏の樹脂組成物を基紙にコーティングする前に、基紙にコロナ放電処理、火炎処理などの活性化処理を施すのが好ましい。また、特公昭61-42254号公報に記載の如く、基紙に接する側の溶融樹脂組成物にオゾン含有ガスを吹きつけた後に走行する基紙に樹脂層を被覆しても良い。また、表、裏の樹脂層は逐次、好ましくは連続的に、押し出しコーティングされる、所謂タンデム押し出しコーティング方式で基紙に被覆されるのが好ましく、必要に応じて裏の樹脂層も二層以上の多層構成で被覆しても良い。また、画像材料用支持体の表樹脂層面は光沢面、特公昭62-19732号公報に記載の微粗面、マット面あるいは絹目面等に加工することが出来、裏樹脂層は通常無光沢面に加工するのが好ましい。
【００５７】
本発明における画像材料用支持体の表樹脂層の被覆厚さとしては、８〜１００μmの範囲が有用であるが、１２〜６０μmの範囲が好ましく、１８〜４０μmの範囲が特に好ましい。また、本発明における特に好ましい画像材料用支持体である、樹脂層が少なくとも最下層から成る樹脂層と少なくとも最上層から成る樹脂層を逐次に溶融押し出しコーティングして被覆された多層構成の場合、少なくとも最下層から成る樹脂層の厚さとしては、画像材料及びそのプリントの見た目の光沢感の改良効果の観点から、表側の全樹脂層厚さの２５%以上の厚さが好ましく、３９%以上の厚さが一層好ましく、５０%以上の厚さが特に好ましいが、特に制限されるものではない。また、裏側の基紙面は、フィルム形成能ある樹脂を主成分とする裏樹脂層で好ましくは被覆されるが、その樹脂はポリエチレン系樹脂が好ましく、その被覆厚さとしては表側の樹脂層と、特にカールバランスを取る範囲で適宜設定するのが好ましく、一般に８〜１００μmの範囲が有用であるが、好ましくは１２〜６０μmの範囲である。
【００５８】
本発明における画像材料用支持体の表樹脂層面上には、コロナ放電処理、火炎処理などの活性化処理を施した後、特開昭61-84643号公報、特開平1-92740号公報、特開平1-102551号公報、特開平1-166035号公報等に記載もしくは例示のような下引層を塗設することができる。また、本発明における画像材料用支持体の裏樹脂層面上には、コロナ放電処理、火炎処理などの活性化処理を施した後、帯電防止等のために各種のバックコート層を塗設することができる。また、バックコート層には、特公昭52-18020号公報、特公昭57-9059号公報、特公昭57-53940号公報、特公昭58-56859号公報、特開昭59-214849号公報、特開昭58-184144号公報等に記載もしくは例示の無機帯電防止剤、有機帯電防止剤、親水性バインダー、ラテックス、硬化剤、顔料、界面活性剤等を適宜組み合わせて含有せしめることができる。
【００５９】
本発明における画像材料用支持体は、各種の写真構成層が塗設されてカラー写真印画紙用、白黒写真印画紙用、写植印画紙用、複写印画紙用、反転写真材料用、銀塩拡散転写法ネガ用及びポジ用、印刷材料用等各種の用途に用いることができる。例えば、塩化銀、臭化銀、塩臭化銀、沃臭化銀、塩沃臭化銀乳剤層を設けることができる。ハロゲン化銀写真乳剤層にカラーカプラーを含有せしめて、多層ハロゲン化銀カラー写真構成層を設けることができる。また、銀塩拡散転写法用写真構成層を設けることができる。それらの写真構成層の結合剤としては、通常のゼラチンの他に、ポリビニルピロリドン、ポリビニルアルコール、多糖類の硫酸エステル化合物などの親水性高分子物質を用いることができる。また、上記の写真構成層には各種の添加剤を含有せしめることができる。例えば、増感色素として、シアニン色素、メロシアニン色素など、化学増感剤として、水溶性金化合物、イオウ化合物など、カブリ防止剤もしくは安定剤として、ヒドロキシ−トリアゾロピリミジン化合物、メルカプト−複素環化合物など、硬膜剤としてホルマリン、ビニルスルフォン化合物、アジリジン化合物など、塗布助剤として、アルキルベンゼンスルフォン酸塩、スルホコハク酸エステル塩など、汚染防止剤として、ジアルキルハイドロキノン化合物など、そのほか蛍光増白剤、鮮鋭度向上色素、帯電防止剤、ｐＨ調製剤、カブらせ剤、更にハロゲン化銀の生成・分散時に水溶性イリジウム、水溶性ロジウム化合物などを適宜組み合わせて含有せしめることができる。
【００６０】
本発明に係る写真材料は、その写真材料に合わせて「写真感光材料と取扱法」（共立出版、宮本五郎著、写真技術講座２）に記載されている様な露光、現像、停止、定着、漂白、安定などの処理を行うことが出来る。また、多層ハロゲン化銀カラー写真材料は、ベンジルアルコール、タリウム塩、フェニドンなどの現像促進剤を含む現像液で処理してもよいし、ベンジルアルコールを実質的に含まない現像液で処理することもできる。
【００６１】
本発明における画像材料用支持体は、各種の熱移行型熱転写記録受像層が塗設されて各種の熱移行型熱転写記録受像材料用支持体として用いることができる。それらの熱移行型熱転写記録受像層に用いられる合成樹脂としては、ポリエステル樹脂、ポリアクリル酸エステル樹脂、ポリカーボネート樹脂、ポリ酢酸ビニル樹脂、ポリビニルブチラール樹脂、スチレンアクリレート樹脂、ビニルトルエンアクリレート樹脂等のエステル結合を有する樹脂、ポリウレタン樹脂等のウレタン結合を有する樹脂、ポリアミド樹脂等のアミド結合を有する樹脂、尿素樹脂等の尿素結合を有する樹脂、その他ポリカプロラクタム樹脂、スチレン系樹脂、ポリ塩化ビニル樹脂、塩化ビニル−酢酸ビニル共重合体樹脂、ポリアクリロニトリル樹脂等を挙げられる。これら樹脂に加えて、これらの混合物もしくは共重合体等も使用できる。
【００６２】
本発明に係わる熱移行型熱転写記録受像層中には、上記合成樹脂の他に離型剤、顔料等を加えても良い。上記離型剤としては、ポリエチレンワックス、アミドワックス、テフロンパウダー等の固形ワックス類、弗素系、リン酸エステル系界面活性剤、シリコーンオイル類等が挙げられる。これら離型剤の中でシリコーンオイルが最も好ましい。上記シリコーンオイルとしては、油状の物も使用できるが、硬化型のものが好ましい。硬化型のシリコーンオイルとしては、反応硬化型、光硬化型、触媒硬化型等が挙げられるが、反応硬化型のシリコーンオイルが特に好ましい。反応硬化型シリコーンオイルとしては、アミノ変性シリコーンオイル、エポキシ変性シリコーンオイル等が挙げられる。上記反応性シリコーンオイルの添加量は、受像層中に０.１〜２０wt%が好ましい。上記顔料としては、シリカ、炭酸カルシウム、酸化チタン、酸化亜鉛等の体質顔料が好ましい。また、受像層の厚さとしては、０.５〜２０μmが好ましく、２〜１０μmが更に好ましい。
【００６３】
本発明における画像材料用支持体は、各種のインク受像層が塗設されて各種のインクジェット記録材料用支持体として用いることができる。それらのインク受像層中にはインクの乾燥性、画像の鮮鋭性等を向上させる目的で各種のバインダーを含有せしめることができる。それらのバインダーの具体例としては、石灰処理ゼラチン、酸処理ゼラチン、酵素処理ゼラチン、ゼラチン誘導体、例えばフタール酸、マレイン酸、フマール酸等の二塩基酸の無水物と反応したゼラチン等の各種のゼラチン、各種ケン化度の通常のポリビニルアルコール、カルボキシ変性、カチオン変性及び両性のポリビニルアルコール及びそれらの誘導体、酸化澱粉、カチオン化澱粉、エーテル化澱粉等の澱粉類、カルボキシメチルセルロース、ヒドロキシエチルセルロース等のセルロース誘導体、ポリビニルピロリドン、ポリビニルピリジウムハライド、ポリアクリル酸ソーダ、アクリル酸メタクリル酸共重合体塩、ポリエチレングリコール、ポリプロピレングリコール、ポリビニルエーテル、アルキルビニルエーテル・無水マレイン酸共重合体、スチレン・無水マレイン酸共重合体及びそれらの塩、ポリエチレンイミン等の合成ポリマー、スチレン・ブタジエン共重合体、メチルメタクリレート・ブタジエン共重合体等の共役ジエン系共重合体ラテックス、ポリ酢酸ビニル、酢酸ビニル・マレイン酸エステル共重合体、酢酸ビニル・アクリル酸エステル共重合体、エチレン・酢酸ビニル共重合体等の酢酸ビニル系重合体ラテックス、アクリル酸エステル重合体、メタクリル酸エステル重合体、エチレン・アクリル酸エステル共重合体、スチレン・アクリル酸エステル共重合体等のアクリル系重合体または共重合体のラテックス、塩化ビニリデン系共重合体ラテックス等あるいはこれらの各種重合体のカルボキシル基等の官能基含有単量体による官能基変性重合体ラテックス、メラミン樹脂、尿素樹脂等の熱硬化合成樹脂系等の水性接着剤及びポリメチルメタクリレート、ポリウレタン樹脂、不飽和ポリエステル樹脂、塩化ビニル・酢酸ビニルコーポリマー、ポリビニルブチラール、アルキッド樹脂等の合成樹脂系接着剤、特公平3-24906号公報、特開平3-281383号公報、特願平4-240725号公報に記載もしくは例示のアルミナゾル、シリカゾル等の無機系バインダー等をあげることができ、これらを単独あるいは併用して含有せしめることができる。
【００６４】
本発明に係わるインクジェット記録材料のインク受像層中には、バインダーの他に各種の添加剤を含有せしめることができる。例えば、界面活性剤として、長鎖アルキルベンゼンスルフォン酸塩、長鎖、好ましくは分枝アルキルスルフォコハク酸エステル塩などのアニオン系界面活性剤、長鎖、好ましくは分岐アルキル基含有フェノールのポリアルキレンオキサイドエーテル、長鎖アルキルアルコールのポリアルキレンオキサイドエーテル等のノニオン系界面活性剤、特公昭47-9303号公報、米国特許3,589,906号明細書等に記載のフルオロ化した界面活性剤など、γ−アミノプロピルトリエトキシシラン、Ｎ−β（アミノエチル）γ−アミノプロピルトリメトキシシランなどのシランカップリング剤、ポリマーの硬膜剤として、活性ハロゲン化合物、ビニルスルフォン化合物、アジリジン化合物、エポキシ化合物、アクリロイル化合物、イソシアネート化合物等の硬膜剤、防腐剤として、特開平1-102551号公報に記載もしくは例示のＰ−ヒドロキシ安息香酸エステル化合物、ベンズイソチアゾロン化合物、イソチアゾロン化合物等、特開昭63-204251号公報、特開平1-266537号公報等に記載もしくは例示の着色顔料、着色染料、蛍光増白剤など、黄変防止剤としてヒドロキシメタンスルフォン酸ソーダ、Ｐ−トルエンスルフィン酸ソーダ等、紫外線吸収剤として、ヒドロキシ−ジ−アルキルフェニル基を２位に有するベンゾトリアゾール化合物など、酸化防止剤として、特開平1-105245号公報に記載もしくは例示のポリヒンダードフェノール化合物など、鉛筆加筆剤として、澱粉粒、硫酸バリウム、二酸化珪素等の有機または無機の粒子径０.２〜５μmの微粒子、特公平4-1337号公報等に記載もしくは例示のオルガノポリシロキサン化合物、ｐＨ調節剤として、苛性ソーダ、炭酸ソーダ、硫酸、塩酸、リン酸、クエン酸など、オクチルアルコール、シリコン系消泡剤などの各種の添加剤を適宜組み合わせて含有せしめることができる。
【００６５】
【実施例】
以下、実施例により本発明を詳しく説明するが、本発明の内容は実施例に限られるものではない。
【００６６】
実施例１〜６及び比較例１〜５
本発明における広葉樹漂白クラフトパルプの製造工程においては、特開昭60-69649号公報に記載の条件で蒸解後、未晒クラフトパルプを第一段階の洗浄工程で洗浄処理し、その後酸素脱リグニン処理（処理条件：パルプ濃度が未晒パルプ絶乾重量として１５重量%、苛性ソーダ及び酸素の添加量が未晒パルプ絶乾重量当たりそれぞれ１.５重量%及び１.０重量%、処理温度及び処理時間がそれぞれ１１０℃及び４５分であった）し、酸素脱リグンニン処理後第２段階の洗浄工程で洗浄処理し、以後の工程で特開昭60-69649号公報に記載の条件で「ＣＥＨＤＥＤＰ］の方式で漂白処理した。漂白処理された広葉樹漂白クラフトパルプは、精選工程で液体サイクロン方式のクリーナー等を用いて精選し、パルプ濃度が絶乾重量として４重量%の濃度で叩解工程に送り、パルプ繊維長が表１の記載のものになるように叩解した。一方、比較用の広葉樹漂白クラフトパルプの製造工程においては、精選後シートマシーンに送り、絶乾水分率が１５重量%であるパルプシートに抄造した。抄造したパルプシートは叩解工程に搬送し、パルプ繊維長が表１の記載のものになるように叩解した。
【００６７】
叩解後、パルプ１００重量部に対して、カチオン化澱粉３重量部、アニオン化ポリアクリルアミド０.２重量部、アルキルケテンダイマー乳化物（ケテンダイマー分として）０.４重量部、ポリアミドエピクロルヒドリン樹脂０.４重量部及び適当量の蛍光増白剤、青色染料、赤色染料を添加して紙料スラリーを調製した。その後、紙料スラリーを２００m/分で走行している長網抄紙機にのせ適切なタービュレンスを与えつつ紙匹を形成し、ウェットパートで１５〜１００kgf/cmの範囲で線圧が調節された３段のウェットプレスを行った後、スムージングロールで処理し、引き続く乾燥パートで３０〜７０kgf/cmの範囲で線圧が調節された２段の緊度プレスを行った後、乾燥した。その後、乾燥の途中でカルボキシ変性ポリビニルアルコール４重量部、蛍光増白剤０.０５重量部、青色染料０.００２重量部、塩化ナトリウム４重量部及び水９２重量部から成るサイズプレス液を２５g/m²サイズプレスし、最終的に得られる基紙水分が絶乾水分率で８重量％になるように乾燥し、線圧７０kgf/cmでマシンカレンダー処理して、坪量１７０g/m²の、密度が１.０４g/cm³、膜厚むら指数Ｒｐｙが１８０mVである画像材料用支持体の基紙を製造した。
【００６８】
次に、画像形成層を設ける側とは反対側の基紙面（裏面）をコロナ放電処理した後、該裏面に下記の樹脂組成物（Ｒ１）を樹脂温度３１５℃で２０μmの樹脂厚さに基紙の走行速度２００m/分で溶融押し出しコーティングした。この際、冷却ロールとしては、下記バック層を塗設後の該バック層面の中心面平均粗さＳＲａが１.１５μmになる粗面度のものを用いた。なお、使用した冷却ロールは液体ホーニング法で粗面化された冷却ロールで、冷却水温度１２℃で操業した。
【００６９】
樹脂組成物（Ｒ１）：高密度ポリエチレン樹脂（密度０.９６７g/cm³、ＭＦＲ＝１５g/10分）７０重量部と低密度ポリエチレン樹脂（密度０.９２４g/cm³、ＭＦＲ＝０.６g/10分）３０重量部とを溶融押し出し機を用いて予め溶融・混合して調製したコンパウンド樹脂組成物であり、そのペレットとして使用した。
【００７０】
引き続き、基紙の表面をコロナ放電処理した後、表樹脂層(1)として、該表面にチューブラ法低密度ポリエチレン樹脂[密度０.９１８g/cm³、ＭＦＲ＝８.５g/１０分、融点１０８℃、以下、低密度ポリエチレン樹脂（Ｒ２）と略す]４７.５重量%、含水酸化アルミニウム（対二酸化チタンに対してＡｌ₂Ｏ₃分として０.５０重量%）で表面処理したアナターゼ型二酸化チタン顔料５０重量％とステアリン酸亜鉛２.５重量%および酸化防止剤、テトラキス〔メチレン−３（３、５−ジ−tert−ブチル−４−ヒドロキシフェニル）プロピオネート〕メタン１５０ppmから成る二酸化チタン顔料マスターバッチ[以下、マスターバッチ（ＭＢ−１）と略す]１７重量部、低密度ポリエチレン樹脂（Ｒ２）４６.２５重量%、上記二酸化チタン顔料５０重量%、群青（第一化成工業株式会社製、#２０００）１.２５重量%とステリアン酸亜鉛２.５重量%、上記酸化防止剤１５０ppmから成る二酸化チタン顔料マスターバッチ[以下、マスターバッチ（ＭＢ−２）と略す]８重量部、オートクレーブ法低密度ポリエチレン樹脂[密度０.９２０g/cm³、ＭＦＲ＝４.５g/１０分、融点１０９℃、以下、低密度ポリエチレン樹脂（Ｒ３）と略す]５７.６重量部とフィリップス法高密度ポリエチレン樹脂[密度０.９６７g/cm³、ＭＦＲ＝７.０g/１０分、融点１３０℃、以下、高密度ポリエチレン樹脂（Ｒ４）と略す]１７.４重量部から成る樹脂組成物を樹脂温度３１５℃で２８μmの厚さに基紙の走行速度２００m/分で溶融押し出し機を用いて、鏡面の冷却ロールとプレスロールの線圧４０kgf/cmで溶融押し出しコーティングした。なお、表、裏のポリエチレン樹脂の溶融押し出しコーティングは、逐次溶融押し出しコーティングが行われる、いわゆるタンデム方式で行われた。その際、該樹脂被覆紙の二酸化チタン顔料を含む樹脂層の表面は、グロッシー面に加工した。
【００７１】
別途、基紙の表面をコロナ放電処理後、表樹脂層(2)として、該表面に下層の樹脂層として、厚さ１４μmの表樹脂層(1)と同じ樹脂組成物、上層の樹脂層として、厚さ１４μmの表樹脂層(1)と同じ樹脂組成物をそれぞれの樹脂温度３１５℃で基紙の走行速度２００m/分で、二層共押し出し機を用いて、鏡面の冷却ロールとプレスロールの線圧４０kgf/cmで二層同時押し出しコーティングする以外は、表樹脂層(1)を被覆する場合と同様にして樹脂被覆を行った。
【００７２】
また別途、基紙の表面をコロナ放電処理後、表樹脂層(3)として、該表面に下層の樹脂層として、厚さ１４μmの表樹脂層(1)と同じ樹脂組成物、上層の樹脂層として、厚さ１４μmの表樹脂層(1)と同じ樹脂組成物をそれぞれの樹脂温３１５℃で基紙の走行速度２００m/分で、下層、その後に上層の順に別個のステーションで溶融押し出し機を用いて、鏡面の冷却ロールとプレスロールの線圧４０kgf/cmで逐次溶融押し出しコーティングする以外は、表樹脂層(1)を被覆する場合と同様にして樹脂被覆を行った。
【００７３】
更に、表、裏樹脂層を加工後巻き取るまでの間に、樹脂被覆紙の裏樹脂層面にコロナ放電処理後、下記のバック層用塗液をオンマシン塗布した。乾燥重量分として、コロイド状シリカ：スチレン系ラテックス＝１：１から成り、更にポリスチレンスルフォン酸ソーダ０.０２１g/m²の他適量の塗布助剤等を含むバック層用塗液をラテックス分（固形重量計算で）として０.２１g/m²になる塗布量で塗設した。
【００７４】
バック層を塗設後、樹脂被覆紙を巻き取るまでの間に、表側の樹脂面にコロナ放電処理を施し、石灰処理ゼラチン１.２g、低分子量ゼラチン（新田ゼラチン株式会社製、Ｐ−３２２６）０.３g、パラオキシ安息香酸ブチルの１０重量%メタノール溶液０.３g及びスルフォコハク酸−２−エチルヘキシルエステル塩のメタノールと水の５重量%混合液０.４５gを含み、全量を水で１００gに調製した配合の下引塗液をゼラチン塗布量０.０６g/m²になるように均一にオンマシン塗布して画像材料用支持体を得た。
【００７５】
各々の画像材料用紙支持体を製造するときの表樹脂層の冷却ロールからの剥離性の評価方法としては、支持体製造時の全体的な剥離の不規則性を目視で観察すると共に得られた画像材料用支持体の表側の表面状態を斜光で観察し、剥離むらの発生の程度を視覚的に判定して、１０段階のグレード評価を行った。評価基準（グレード数値の大きいほど剥離性が良好であり、グレード数値の小さいほど剥離性が悪いことを表す）としては、以下の通りである。
【００７６】
グレード１０〜９：冷却ロールからの剥離は不規則性が全くなく、剥離むらの発生が全くあるいはほとんどなく、剥離性が極めて良好。
グレード ８〜７：冷却ロールからの剥離は不規則性がほとんどなく、剥離むらの発生が軽微で、剥離性が良好。
グレード ６〜５：冷却ロールからの剥離はわずかな不規則性を示し、剥離むらの発生がややあるが、実用上問題ない程度。
グレード ４〜１：冷却ロールからの剥離は不規則性を示し、剥離むらの発生が多く、実用上問題である。
【００７７】
次に、画像材料用支持体を有する写真プリントの見た目の光沢感の評価方法としては、以下に記載の方法で評価した。
【００７８】
画像材料用支持体の下引層上に隣接して順に、黄色発色カプラーを含む青感乳剤層、色混り防止剤を含む中間層、マゼンタ発色カプラーを含む緑感乳剤層、紫外線吸収剤を含む紫外線吸収層、シアン発色カプラーを含む赤感乳剤層及び保護層を多層塗布用Ｅバーにより塗設してゼラチンの総量が７g/m²であるカラー印画紙を作成した。各色感乳剤層は硝酸銀で０.６g/m²に相当する塩臭化銀を含み、更にハロゲン化銀の生成、分散及び成膜に必要なゼラチンの他、適量のカブリ防止剤、増感色素、塗布助剤、硬膜剤、増粘剤及び適量のフィルター染料などを含む。
【００７９】
次に、作成したカラー印画紙を３５℃、常湿下に５日間保存後、集合写真を焼き付け、現像、漂白・定着、安定の現像処理をした後乾燥し、写真プリントを作成した。又、別途白べた（未露光）及び黒べた（黒色発色）の焼き見本も作成した。なお、露光、現像、乾燥の一連の処理は、自動プリンター及び自動現像機により行った。なお、発色現像処理は、発色現像（４５秒）→漂白・定着（４５秒）→安定（９０秒）→乾燥の手順で行われた。
【００８０】
得られた集合写真、白べた及び黒べたの写真プリントについて、１０人のモニターにより視覚的に写真プリントの見た目の光沢感を総合的に評価した。
【００８１】
写真プリントの見た目の光沢感の評価基準としては、以下の通りである。
◎：見た目の光沢感が極めて高い。
◎〜○：見た目の光沢感がかなり高い。
○ ：見た目の光沢感が一層高い。
○〜□：見た目の光沢感が高い。
□ ：見た目の光沢感がやや高い。
△ ：見た目の光沢感がやや低いが、実用可能である。
× ：見た目の光沢感が低く、実用上問題がある。
【００８２】
得られた結果を表１に示す。
【００８３】
【表１】

【００８４】
表１の結果から、広葉樹漂白クラフトパルプを製造後ドライパルプにすることなく、叩解工程に送られ、叩解された広葉樹漂白クラフトパルプを含む紙を基質とする、本発明における画像材料用支持体（実施例１〜６）は、写真プリントの見た目の光沢感が高く、かつ剥離性が良好で剥離むらの発生が無い、優れた画像材料用支持体であることがよくわかる。
【００８５】
特に、写真プリントの見た目の光沢感の改良効果の点から、繊維長が０.４５mm〜０.６５mmの範囲であるパルプを用いた画像材料用支持体が好ましいことがよくわかる（実施例１と４、実施例２と５、実施例３と６の比較）。また、特に写真プリントの見た目の光沢感及び剥離性の改良効果の点から、表樹脂が多層構成である画像材料用支持体が好ましいことがよくわかる（実施例１と実施例２または３及び実施例４と実施例５または６の比較）。更に、写真プリントの見た目の光沢感及び剥離性の改良効果の点から、逐次方式（逐次溶融押し出しコーティング方式と同意義である）で表樹脂層が多層構成にされた画像材料用支持体（実施例３と６）が更に好ましく、繊維長が０.４５mm〜０.６５mmの範囲であるパルプを用い、かつ逐次方式で表樹脂層が多層構成にされた画像材料用支持体（実施例３）が、最も好ましいことがよくわかる。
【００８６】
一方、絶乾水分率が５０%未満であるドライパルプを用いた紙を基質とする、本発明外の画像材料用支持体（比較例１〜５）は、写真プリントの見た目の光沢感が低くて問題があることがよくわかる。逐次方式で表樹脂層を多層構成にした場合（比較例３）でも、見た目の光沢感の改良効果は十分でなく、本発明の有効性が明らかであることがよくわかる（実施例３と比較例３の比較）。
【００８７】
実施例７〜１２及び比較例６
実施例３で用いたパルプの代わりに、表２に記載の構成のパルプを用いる以外は実施例３と同様にして実施した。
【００８８】
得られた結果を表２に示す。
【００８９】
【表２】

【００９０】
なお、表２中、（Ｐ１）は実施例３で用いたパルプであり、（Ｐ２）は比較例３で用いたパルプである。また、パルプは別叩解または共叩解を行い、構成されたパルプの繊維長が０.５５mmになるように叩解した。
【００９１】
表２の結果から、本発明の実施に用いられるノンドライ広葉樹漂白クラフトの基紙中の含有量としては、写真プリントの見た目の光沢感の改良効果の点から、基紙を構成する全パルプに対して、絶乾重量%で２０重量%以上が有用であり、４０重量%以上が好ましく、６０重量%以上が一層好ましく、８０重量%以上が特に好ましいことがよくわかる。
【００９２】
実施例１３〜１５及び比較例７〜８
実施例２で用いたパルプの代わりに、下記のパルプ（Ｐ１）〜（Ｐ５）を用いる以外は実施例２と同様に実施した。
パルプ（Ｐ１）：実施例２で用いたパルプ、絶乾重量%でパルプ濃度が４重量%のスラリー形態であるパルプ。
パルプ（Ｐ２）：比較例２で用いたパルプ、絶乾水分率が１５重量%であるドライパルプ。
パルプ（Ｐ３）：パルプ（Ｐ２）と同様に製造され、絶乾水分率が４５重量%であるウェットパルプ。
パルプ（Ｐ４）：パルプを漂白、精選後フィルター及びプレス（ロールプレス及びスクリュウープレス）で圧搾された絶乾水分率６０重量%であるパルプ濃縮物。
パルプ（Ｐ５）：パルプ（Ｐ４）と同様に製造された、絶乾水分率が７５重量%であるパルプ濃縮物。
【００９３】
得られた結果を表３に示す。
【００９４】
【表３】

【００９５】
表３の結果から、広葉樹漂白クラフトパルプを製造後ドライパルプまたは絶乾水分率が５０重量%未満であるウェットパルプにすることなく、叩解工程に送られ、叩解された広葉樹漂白クラフトパルプを含む紙を基質とする、本発明における画像材料用支持体（実施例１３〜１５）は、写真プリントの見た目の光沢感が高い、優れた画像材料用支持体であることがよくわかる。また、本発明の実施に用いるパルプとしては、絶乾水分率が５０重量%以上のものが有用であるが、７５重量%以上のものが好ましく、パルプ濃度が、絶乾重量%で１０重量%以下のスラリー形態のものが特に好ましいことがよくわかる。
【００９６】
実施例１６〜１８及び比較例９〜１０
実施例３で用いたパルプに代わり、実施例１３〜１５及び比較例７〜８で用いたパルプ（Ｐ１）〜（Ｐ５）を用いる以外は実施例３と同様に実施した。
【００９７】
得られた結果を表４に示す。
【００９８】
【表４】

【００９９】
表４の結果から、広葉樹漂白クラフトパルプを製造後ドライパルプまたは絶乾水分率が５０%重量%未満であるウェットパルプにすることなく、叩解工程に送られ、叩解された広葉樹漂白クラフトパルプを含む紙を基質とする、本発明における画像材料用支持体（実施例１６〜１８）は、写真プリントの見た目の光沢感が高い、かつ剥離性が良好で剥離むらの発生が無い、優れた画像材料用支持体であることがよくわかる。また、本発明の実施に用いるパルプとしては、絶乾水分率が５０重量%以上のものが有用であるが、７５重量%以上のものが好ましく、パルプ濃度が、絶乾重量%で１０重量%以下のスラリー形態のものが特に好ましいことがよくわかる。
【０１００】
また、表３と表４の比較から、本発明においては、写真プリントの見た目の光沢感の改良効果及び剥離性の改良効果の点から、逐次方式で表樹脂層が多層構成にされた画像材料用支持体（実施例１６〜１８）が、最も好ましいことがよくわかる。
【０１０１】
実施例１９〜２７
パルプの種類としては、実施例２と同じパルプ（Ｐ１）を用いるが、パルプの繊維長が表５に記載のものになるように叩解したパルプを用いる以外は実施例２と同様に実施した。
【０１０２】
得られた結果を表５に示す。
【０１０３】
【表５】

【０１０４】
なお、画像材料の腰の強さの評価方法としては、１３cm×１８cmのカラー写真プリントについて、１０人のモニターによりカラー写真プリントの端を持って上下に振り、手触り感による腰の強さを評価した。評価基準としては、○：腰が極めてまたはかなり強い、○〜□：腰が強い、□：腰がやや強い、△：腰がやや弱いが、実用可能である程度、×：腰が弱く、実用上問題がある程度を表す。
【０１０５】
表５の結果から、本発明の実施に用いられるノンドライ広葉樹漂白クラフトパルプとしては、写真プリントの見た目の光沢感及び画像材料の腰の強さの観点から、繊維長が０.４５mm〜０.６５mmの範囲のものが好ましく、０.４７mm〜０.６２mmの範囲のものが更に好ましく、０.４９mm〜０.５９mmの範囲のものが特に好ましいことがよくわかる。
【０１０６】
実施例２８〜３４
実施例３で用いた表樹脂層（３）の上層用または下層用の樹脂組成物の代わりに、下記の樹脂組成物（３ＵＡ）〜（３ＵＤ）または（３ＬＥ）〜（３ＬＧ）を、表８の組み合わせで用いること及び基紙の走行速度を３００m/分にすること以外は実施例３と同様に実施した。
【０１０７】
（上層用樹脂組成物）：（３ＵＡ）〜（３ＵＤ）
樹脂組成物（３ＵＡ）：実施例３で用いたマスターバッチ（ＭＢ−１）１７重量部と実施例３で用いたマスターバッチ（ＭＢ−２）８重量部と実施例３で用いた低密度ポリエチレン樹脂（Ｒ３）７５重量部から成る樹脂組成物。
【０１０８】
樹脂組成物（３ＵＢ）：実施例３で用いたものと同じ上層用樹脂組成物（上層中の全樹脂成分に対する高密度ポリエチレン樹脂の含有率、２０.１重量%）。
【０１０９】
樹脂組成物（３ＵＣ）：マスターバッチ（ＭＢ−１）１７重量部とマスターバッチ（ＭＢ−２）８重量部と低密度ポリエチレン樹脂（Ｒ３）４０.２重量部と高密度ポリエチレン樹脂（Ｒ４）３４.８重量部（上層中の全樹脂成分に対する高密度ポリエチレン樹脂の含有率、４０.１重量%）から成る樹脂組成物。
【０１１０】
樹脂組成物（３ＵＤ）：マスターバッチ（ＭＢ−１）２１重量部とマスターバッチ（ＭＢ−２）９重量部と低密度ポリエチレン樹脂（Ｒ３）５３.１重量部と高密度ポリエチレン樹脂（Ｒ４）１６.９重量部（上層中の全樹脂成分に対する高密度ポリエチレン樹脂の含有率、２０.１重量%）から成る樹脂組成物。
【０１１１】
（下層用樹脂組成物）：（３ＬＥ）〜（３ＬＧ）
樹脂組成物（３ＬＥ）：実施例３で用いたものと同じ下層用樹脂組成物。
【０１１２】
樹脂組成物（３ＬＦ）：密度０.９２４g/cm³、ＭＦＲ４.５g/１０分、融点１１１℃のオートクレーブ法低密度ポリエチレン樹脂。
【０１１３】
樹脂組成物（３ＬＧ）：密度０.９２４g/cm³、ＭＦＲ３.０g/１０分、融点１１１℃のチューブラ法低密度ポリエチレン樹脂。
【０１１４】
得られた結果を表６に示す。
【０１１５】
【表６】

【０１１６】
表６の結果より、本発明において好ましい画像材料用支持体である、表樹脂層が多層構成にされた画像材料用支持体の中でも、写真プリントの見た目の光沢感及び剥離性の改良効果の点から、最上層中に、それより下側の樹脂層中の樹脂よりも密度または融点の高い樹脂を少なくとも１種含有せしめるのが好ましいことがよくわかる。また、最上層より下側の樹脂層中の二酸化チタン顔料、着色顔料、離型剤、酸化防止剤などの添加剤の含有割合を、最上層中の添加剤の含有割合より低くしても、本発明の効果に全く問題なく、経済的に有利であることがよくわかる。
【０１１７】
実施例３５〜３８
実施例３２において、表樹脂層を逐次溶融押し出しコーティングする際に、上層及び下層用樹脂組成物の樹脂温度として、表７に記載の樹脂温度にする以外は実施例３と同様に実施した。
【０１１８】
得られた結果を表７に示す。
【０１１９】
【表７】

【０１２０】
表７の結果から、本発明においては、剥離性の改良効果の点から、多層構成である表樹脂層用の樹脂組成物を溶融押し出しコーティングするに際して、最上層用の樹脂組成物の温度をそれより下側の樹脂層を構成する樹脂組成物の温度より低くすることが好ましいことがよくわかる。
【０１２１】
実施例３９〜４３
実施例３２において、表樹脂層の上層及び下層の被覆厚さとして表８に記載の被覆厚さにする以外は実施例３２と同様に実施した。
【０１２２】
得られた結果を表８に示す。
【０１２３】
【表８】

【０１２４】
表８の結果から、本発明において好ましい画像材料用支持体である、表樹脂層が多層構成にされた画像材料用支持体の中でも、写真プリントの見た目の光沢感及び剥離性の改良効果の点から、少なくとも最下層から成る樹脂層の厚さが、全樹脂層厚さの２５%以上の厚さが好ましく、３９%以上の厚さが一層好ましく、５０%以上の厚さが特に好ましいことがよくわかる。
【０１２５】
実施例４４〜４６
実施例２で用いた表樹脂層（２）の上層用並びに下層用の樹脂組成物の代わりに、上層用の樹脂組成物として樹脂組成物（３ＵＤ）を用いること並びに下層用の樹脂組成物として樹脂組成物（３ＬＦ）を用いること及び基紙の走行速度を表９に記載の走行速度にすること以外は実施例２と同様に実施した。
【０１２６】
得られた結果を表９に示す。
【０１２７】
実施例４７〜４９
実施例３２において、基紙の走行速度を表９に記載の走行速度にすること以外は実施例３２と同様に実施した。
【０１２８】
得られた結果を表９に示す。
【０１２９】
【表９】

【０１３０】
表９の結果、即ち実施例４４と実施例４７（各々基紙の走行速度２００m/分）、実施例４５と実施例４８（各々基紙の走行速度２５０m/分）及び実施例４６と実施例４９（各々基紙の走行速度３００m/分）の結果の比較から、基紙の走行速度（即ち、画像材料用支持体の製造速度）が速くなればなる程、即ち基紙の走行速度が、２００m/分以上、更には２５０m/分以上、特に３００m/分以上である場合には、写真プリントの見た目の光沢感及び剥離むらの改良効果の点から、本発明における画像材料用支持体の中でも逐次溶融押し出しコーティング方式で表樹脂層が多層構成にされた画像材料用支持体が、特に好ましいことがよくわかる。更に、該画像材料支持体は、見た目の光沢感の高い画像材料及びそのプリントが得られる、かつ剥離むらの発生がない、なおかつ高速かつ安定生産出来る、特に優れた画像材料支持体であることがよくわかる。
【０１３１】
実施例５０
実施例３の画像材料用支持体上に多層ハロゲン化銀カラー写真構成層の代わりに、下記のインク受像層を塗設してインクジェット記録材料を作成した。その結果、該インクジェット記録材料は見た目の光沢感が高くかつ、光沢むらが無く、該画像材料用支持体は優れたものであった。
【０１３２】
インク受像層は、分子量７万のアルカリ処理ゼラチンの１０重量%ゼラチン水溶液３０g、ソジウムカルボキシメチルローズ（エーテル化度０.７〜０.８、Ｂ型粘度計での２重量%水溶液の粘度が５cp以下のもの）の８重量%水溶液３７.５g、エポキシ化合物（長瀬産業株式会社製ＮＥＲ−０１０）の５重量%メタノール溶液０.３g、スルフォコハク酸−２−エチルヘキシルエステル塩のメタノールと水の５重量%混合液０.５g及び純水３１.７gから成る塗液を固形分量で７g/cm²分塗設されて形成された。
【０１３３】
【発明の効果】
本発明により、見た目の光沢感が高い、かつ光沢むらがない画像材料及びそのプリントを提供できる、しかも支持体製造時の冷却ロールからの剥離性が良好であり、それ故高速かつ安定生産できる、紙を基質とする優れた樹脂被覆紙型の画像材料用支持体を提供できる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a resin layer in which a paper substrate (hereinafter sometimes abbreviated as a base paper) on which one of the image forming layers is provided is made of paper mainly composed of natural pulp as a substrate, and a film-forming resin. The image material and its print, particularly silver halide photographic paper and its print (a silver halide photographic paper print, hereinafter simply referred to as a silver halide photographic paper print). The present invention relates to a support for imaging material, which can be abbreviated as photographic print. Furthermore, the present invention can provide an image material and its print, in particular, silver halide photographic paper and photographic print, which have a remarkably high gloss appearance and no unevenness of gloss, and from the cooling roll at the time of producing the support. The present invention relates to a support for imaging materials that has improved peelability, does not cause peeling unevenness, and can be produced stably at high speed.
[0002]
[Prior art]
Usually, the image material is composed of an image material support and an image forming layer provided on the support. For example, a silver halide photographic material, an ink jet recording material, a heat transfer type thermal transfer recording image receiving material, a heat sensitive recording material, and a light sensitive heat sensitive recording material are respectively provided on a support for an image material. An image forming layer such as a transfer-type thermal transfer recording image-receiving layer, a heat-sensitive color developing layer, a light-sensitive and heat-sensitive color developing layer, and an undercoat layer, a protective layer, and the like are provided as necessary. In particular, the silver halide photographic composition layer includes a silver halide photographic emulsion layer, a protective layer, an undercoat layer, an intermediate layer or a color mixing prevention layer, an antihalation layer, a filter layer, an ultraviolet absorption layer, and combinations thereof. It is comprised from. For example, a single silver halide photographic material is a photographic material support provided with a silver halide photographic emulsion layer and a protective layer thereof. Multilayer silver halide color photographic materials are also provided on a support for photographic materials, such as an undercoat layer, a blue-sensitive silver halide photographic emulsion layer and an intermediate layer, a green-sensitive silver halide photographic emulsion layer and an ultraviolet absorbing layer, and a red-sensitive halogen. A silver halide photographic emulsion layer and a silver halide color photographic constituent layer such as a protective layer are provided in this order to form a multilayer arrangement.
[0003]
2. Description of the Related Art Conventionally, a resin-coated paper type support in which a base paper surface for a support for image material is coated with a resin capable of forming a film is well known. As a photographic material support for silver halide photographic material use, for example, in Japanese Patent Publication No. 55-12584, a photographic material whose base paper is coated with a film-forming resin, preferably a polyolefin resin is disclosed. Techniques for the support are disclosed. U.S. Pat. No. 3,501,298 discloses a technique for a photographic material support in which both surfaces of a base paper are coated with a polyolefin resin. In addition, since the rapid photographic development processing method for silver halide photographic materials has been applied, photographic material supports in which both sides of the base paper are coated with polyethylene resin have been put to practical use mainly for photographic paper. If necessary, the resin layer on the side on which one of the image forming layers is provided usually contains a titanium dioxide pigment in order to impart sharpness.
[0004]
In addition, US Pat. No. 4,774,224 supports resin-coated paper having a resin-coated surface roughness of 7.5 microinches-AA or less, particularly polyethylene resin-coated paper in which the surface of the base paper is coated with polyethylene resin. A thermal transfer recording image receiving element having a body has been proposed. Japanese Patent Application Laid-Open No. 63-307979 discloses a technique relating to an ink jet recording sheet having a resin-coated paper as a support.
[0005]
However, the support for resin-coated paper-type image materials, in which the surface on which the image-forming layer of the base paper, particularly the base paper mainly composed of natural pulp is provided, is coated with a resin layer still has some serious problems. The fact is that satisfactory results have not yet been obtained.
[0006]
First, the side on which the image forming layer of the base paper is provided (hereinafter, the side on which the image forming layer is provided is the front side, the resin layer coated on the front side is the front resin layer, the opposite side is the back side, and the resin layer is coated on the back side. The resin-coated paper for use as a support for image materials, in which the surface of the resin layer is coated with a resin layer containing at least a film-forming resin, particularly a polyethylene-based resin, Using a melt extruder, the polyethylene-based resin composition is cast and coated in a film form from the slit die, pressure-bonded between a pressure roll and a cooling roll, and peeled off from the roll after cooling. It is manufactured by the process. At that time, when producing a resin-coated paper for an image material for glossy use, as a cooling roll, a cooling roll having a mirror surface, a glossy surface, or a finely rough surface described in JP-B-62-19732 has a very good smoothness. Is used. Thus, the surface resin layer of the resin-coated paper is processed into a smooth surface because it is pressed against a cooling roll having extremely good smoothness in its molten state, and therefore the image material and the print using the resin-coated paper as a support. Then, it should be possible to obtain a product with a high gloss appearance. However, it was not possible to obtain a sufficiently high glossy appearance with image materials and prints using resin-coated paper actually produced as a support. In particular, with a photographic printing paper using a resin-coated paper as a support, it was not possible to obtain a photographic printing paper and a photographic print with sufficiently high gloss.
[0007]
Therefore, as a result of various studies on the apparent glossiness of the image material and its print, the present inventors have found that the factors affecting the apparent glossiness include the resin-coated paper as the support, the image forming layer, and the development processing. Although there are various factors such as the image forming method, it has been found that the apparent glossiness of the image material and its print is greatly influenced by the factors of the resin-coated paper as the support. Therefore, as a result of various studies on the factors of the resin-coated paper that affect the glossiness of the appearance, the present inventors have determined that the apparent glossiness of the image material and the print depends on the factors of the resin layer and that the natural pulp is the main component. Factors such as the type and properties of the base paper, such as natural pulp type, fiber length, paper slurry conditions such as paper additives contained in the paper slurry, paper making speed, tightness press, machine calendar conditions, etc. It was found that it depends on various factors such as paper making conditions, post-processing conditions such as size press and tab size press, and surface roughness of the base paper. Further, as the thickness of the surface resin layer of the resin-coated paper becomes thinner, particularly when the thickness is 31 μm or less, the image material using the resin-coated paper as a support and the apparent glossiness of the print are more prominent. It turns out that it falls. In particular, glossy photographic materials are required to have a high level of gloss when used in photographic prints, and photographic materials with poor visual glossiness of photographic prints are not suitable for glossy applications. There was a problem that it would have no commercial value.
[0008]
Second, the resin-coated paper for image materials for glossy applications requires a high degree of smoothness, but the more the surface resin layer becomes thicker, especially when extruding a molten resin onto a base paper, In particular, in the case of 20 μm or more, or as the production speed of the resin-coated paper becomes faster, particularly in the case of 200 m / min or more, the peelability of the resin-coated paper from the cooling roll deteriorates, and uneven peeling occurs on the resin-coated paper surface. That is, horizontal unevenness in the width direction is generated. When this unevenness of peeling occurs, the unevenness of gloss also occurs in the image material and print using the resin-coated paper as a support, resulting in a problem that the glossiness of appearance is further reduced and the commercial value is remarkably reduced.
[0009]
Conventionally, there have been several technical proposals for eliminating and improving the above-mentioned problems and other disadvantages of resin-coated paper-type image material supports. Occurred on the surface resin layer surface of a resin-coated paper-type photographic support by the two-layer extrusion coating method of the coextruded coating method and the sequential extrusion coating method described in JP-A-59-198451, JP-A-1-303435, etc. Although there is a description or exemplification of a technique for preventing and improving crater-like pores that tend to form and providing a photographic support excellent in smoothness without surface defects, it is insufficient to solve the above-mentioned problems In particular, it was extremely insufficient for improving and improving the glossiness of the appearance of the image material and the print using the resin-coated paper as a support.
[0010]
On the other hand, for the purpose of improving the smoothness of the resin-coated paper, a pulp having a specific fiber length distribution described in JP-A-58-68037, a specific fiber length described in JP-A-60-69649, Use of specific pulp such as width and thickness pulp, softwood pulp described in JP-A-61-35442, low-viscosity pulp described in JP-A-63-173045, JP-A-58-37642 Use of a base paper having a specific physical property value such as a base paper having a Beck smoothness of not less than a specific value, a surface paper having a surface roughness of not more than a specific value described in JP-A-63-291054, Thermal calendar processing of the base paper described in JP-A-60-126397, papermaking by a paper machine having an upper dewatering mechanism described in JP-A-61-284762, long net described in JP-A-63-204250 Techniques such as the use of a specific paper making method such as paper making by a two-layer paper machine, wet paper tension pressing described in JP-A-64-20541 are disclosed. However, it is insufficient for solving the above-mentioned problems, and particularly, it is extremely insufficient for improving and improving the glossiness of the appearance of the image material and the print using the resin-coated paper as a support.
[0011]
[Problems to be solved by the invention]
Accordingly, a first object of the present invention is to provide a resin in which paper having natural pulp as a main component is used as a substrate, and the paper substrate on which one image forming layer is provided is coated with a resin layer containing a resin capable of forming a film. An excellent resin-coated paper-type image, which is a coated paper and can provide an image material having high glossiness and a print thereof, particularly a silver halide photographic paper and a photographic print, using the resin-coated paper as a support. It is to provide a support for materials. The second object of the present invention is that the resin layer is coated at a production rate of 200 m / min or more, particularly 300 m / min or more, and therefore excellent in productivity and economy, and from the cooling roll at the time of producing the support. With improved releasability, there is no occurrence of unevenness of peeling, and therefore it can be produced at high speed and stably, and the resin-coated paper is used as a support for an image material that has a remarkably high gloss and has no unevenness of gloss. An object of the present invention is to provide an excellent resin-coated paper-type support for imaging material capable of providing such prints, particularly silver halide photographic paper and photographic prints.
[0012]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventor has a paper layer containing natural pulp as a main component, and the paper substrate on the side on which one of the image forming layers is provided contains a resin capable of forming a film. In the substrate for imaging material coated with, the paper substrate is sent to the beating process without making hardwood bleached kraft pulp into dry pulp or wet pulp with an absolute dry moisture content of less than 50% by weight and beating It has been found that the object of the present invention is achieved by a support for imaging materials characterized in that it contains at least the hardwood bleached kraft pulp that has been prepared.
[0013]
The object of the present invention is to make the content of the hardwood bleached kraft pulp in the paper substrate 20% or more, more 40% or more, still more 60% or more, especially 80% or more by weight in absolute dry weight%. It was found that this was achieved significantly. Further, as the hardwood kraft pulp before being sent to the beating process, by using one having a dry moisture content of 75% by weight or more, in particular, a slurry form having a pulp concentration of 10% by weight or less by dry weight%, We found that it was achieved even more markedly.
[0014]
Further, the object of the present invention is to set the fiber length of hardwood bleached kraft pulp after beating to 0.45 mm to 0.65 mm, further 0.47 mm to 0.62 mm, particularly 0.49 mm to 0.59 mm. By doing so, we found that it was achieved significantly.
Pulp fiber length: The pulp after beating, expressed in length-weighted average fiber length (mm) measured according to JAPAN TAPPI paper pulp test method No. 52-89 “Paper and pulp fiber length test method” .
[0015]
Further, it has been found that the object of the present invention can be effectively achieved by constituting the surface resin layer by at least two layers of the lowermost layer and the uppermost layer. In particular, an object of the present invention is that the at least two resin layers are coated by a sequential extrusion coating method in which at least the lowermost resin layer and at least the uppermost resin layer are sequentially melt extrusion coated. It has been found that this can be achieved significantly and synergistically. Further, by making the thickness of the resin layer comprising at least the lowermost layer 25% or more, further 40% or more, particularly 50% or more of the total resin layer thickness, it becomes extremely remarkably and synergistically. I found it to be achieved.
[0016]
Another object of the present invention is to provide the at least two layers by the melt extrusion coating method under the condition that the temperature of the resin composition for the uppermost layer is lower than the temperature of the resin composition constituting the lower resin layer. It has been found that coating the resin layer achieves very significantly and synergistically.
[0017]
Another object of the present invention is to make the content of the additive in the uppermost layer higher than the content of the additive in the lower resin layer, particularly as an additive, white pigment, colored pigment, coloring It has been found that it can be effectively achieved by using dyes, optical brighteners, antioxidants or mold release agents. Further, the object of the present invention is to use a titanium dioxide pigment as a white pigment, and further, the content of the titanium dioxide pigment in the uppermost layer (as a proportion of the weight of the uppermost layer) is 12% by weight or more, particularly 15% by weight or more. It has been found that this can be achieved more effectively.
[0018]
Furthermore, an object of the present invention is to make the running speed of the base paper at the time of coating the base paper with the at least two resin layers 200 m / min or more, further 250 m / min or more, particularly 300 m / min or more, It has been found that this is achieved remarkably and synergistically, and the present invention has been achieved.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
The hardwood bleached kraft pulp used in the practice of the present invention is sent to the beating process and beaten without making dry pulp or wet pulp having an absolute dry moisture content of less than 50% by weight after production. Here, the hardwood bleached kraft pulp that is not made into dry pulp or wet pulp having an absolute dry moisture content of less than 50% by weight is a pulp slurry form or wet form (mainly through pulp digestion process, bleaching process, etc. In the invention, it means hardwood bleached kraft pulp that is sent to the beating process as it is in a form containing an absolute dry moisture content of 50% by weight or more (pulp slurry form or wetness through pulp cooking process, bleaching process, etc. The hardwood kraft pulp that is sent to the beating process in the form may be hereinafter simply referred to as “None Dry hardwood bleached kraft pulp”. Further, the non-dry hardwood bleached kraft pulp referred to in the present specification includes non-dry hardwood softwood mixed bleached kraft pulp.
[0020]
The base paper used in the practice of the present invention is partly or entirely composed of non-dry hardwood bleached kraft pulp, but in combination with non-dry hardwood bleached kraft pulp, other natural pulp, if necessary, It may be composed of synthetic fibers or synthetic pulp. Natural pulp is preferred as pulp used in combination with non-dry hardwood bleached kraft pulp, hardwood bleached kraft pulp (dry pulp or wet pulp) having a moisture content of less than 50% by weight, hardwood bleached sulphite pulp, softwood bleached kraft pulp Wood pulp of softwood bleached sulfite pulp and hardwood softwood mixed bleached sulfite pulp is preferred. Moreover, various things, such as non-wood pulp, soda pulp, dissolved pulp, and other recycled pulp (spent paper pulp) can be used. The content of the non-dry hardwood bleached kraft pulp used in the practice of the present invention in the base paper is not limited to the total pulp constituting the base paper from the viewpoint of the effect of the present invention, particularly the effect of improving the glossiness of appearance. The dry weight% is preferably 20% by weight or more, more preferably 40% by weight or more, still more preferably 60% by weight or more, and particularly preferably 80% by weight or more.
[0021]
As the non-dry hardwood bleached kraft pulp used in the practice of the present invention, the wood chip is a mixed solution containing sodium hydroxide and sodium sulfide as chemical components, so-called cooking liquid, so-called cooking, so that lignin is removed, A product produced by separating and washing into pulp fiber and cooking residue, so-called black liquor in the presence of an antifoaming agent or an antifoaming agent, followed by oxygen delignification treatment and then bleaching treatment is advantageously used. In addition to sodium hydroxide and sodium sulfide, chemical components in the cooking liquor further include salts such as sodium carbonate, sodium sulfate, slaked lime and calcium carbonate, and cooking aids such as sodium borohydride and anthraquinone compounds. May be. Moreover, what was manufactured by various cooking systems, such as a polysulfide cooking, a batch type cooking, a continuous type cooking, may be manufactured by various sulfidity and a copper number. The cooking conditions are as follows: “Paper pulp and non-wood pulp” (published on March 10, 1967) edited by the Japan Paper Pulp Technology Association, Japanese Unexamined Patent Publication No. 60-67940, Japanese Unexamined Patent Publication No. 60-69649 It can be performed under various conditions such as those described.
[0022]
As the non-dry hardwood bleached kraft pulp used in the practice of the present invention, a non-dry hardwood bleached kraft pulp that has been subjected to washing treatment after cooking, then oxygen delignification treatment, preferably further washing treatment, and then bleaching treatment is advantageously used. The treatment conditions for oxygen delignification are preferably set so that the delignification degree in the oxygen delignification stage is 20% to 70%, preferably 40% to 50%. The oxygen delignification treatment is carried out in the presence of at least oxygen and alkali, and preferably an agent for preventing a decrease in the degree of polymerization of the pulp. As oxygen used for the oxygen delignification treatment, oxygen supplied from an oxygen cylinder, oxygen mainly produced from air by an oxygen-enriched film, and the like are advantageously used. In the oxygen delignification treatment, oxygen alone may be used, or an oxygen-based oxidizing agent such as hydrogen peroxide may be used in combination, ozone, nitrogen oxide, or the like. As the alkali used for the oxygen delignification treatment, alkaline liquids such as sodium hydroxide, sodium carbonate, white oxide liquid and green oxide liquid can be used, but it is preferable to use white oxide liquid. Examples of the pulp polymerization degree lowering preventive agent preferably used for the oxygen delignification treatment include magnesium carbonate, magnesium sulfate, and calcium chloride. Specific conditions for the oxygen delignification treatment can be performed under various treatment conditions. For example, specifically, the pulp concentration is 5 wt. To 35 wt.%, Preferably 10 wt.% To 20 wt.% As the dry weight of unbleached pulp, and the oxygen addition amount is the absolute dry weight of unbleached pulp. The range of 0.2 wt% to 4 wt% per weight, preferably the range of 0.5 wt% to 2 wt%, and the amount of alkali added is 0.2 wt% to 7 wt% in terms of caustic soda per dry weight of unbleached pulp. The range is preferably 0.5 wt% to 3 wt%. The treatment temperature for the oxygen delignification treatment is preferably in the range of 50 ° C. to 150 ° C., and the treatment time is preferably in the range of 10 minutes to 180 minutes. Further, the amount of the pulp polymerization degree reduction inhibitor used as necessary is preferably in the range of 0.05 wt% to 1 wt% per the dry weight of unbleached pulp.
[0023]
The non-dry hardwood bleached kraft pulp used in the practice of the present invention has been subjected to bleaching at the stage after cooking, washing, oxygen delignification performed as necessary, and washing. As the bleaching treatment, after the oxygen delignification treatment performed as necessary, the pre-bleaching treatment and the post-bleaching treatment are advantageously performed. In addition, the bleaching process said in this specification is the bleaching process after a pre-stage bleaching process. As the pre-stage bleaching treatment, chlorine treatment using chlorine, ozone treatment without using chlorine, instead of acid treatment, hydrogen peroxide treatment under acidic to neutral conditions, chlorine dioxide treatment under acidic conditions, or 2 of them Two or more combined treatments, such as non-chlorine treatment (Elementary Chlorine Free), or no chlorinated compounds, instead of oxides, for example, ozone treatment under acidic conditions, under acidic or alkaline conditions Treatment with hydrogen peroxide, treatment with other peroxides, or a combination treatment of two or more of them with a total chlorine free (contract TCF treatment). As the subsequent bleaching treatment, alkali extraction, hypochlorite bleaching treatment, one or more chlorine dioxide bleaching treatment, combined treatment of hydrogen peroxide bleaching treatment under alkaline conditions, or TCF treatment, alkali extraction , Peroxide bleaching treatment under acidic or alkaline conditions, one or two or more ozone bleaching treatments under acidic conditions (in some cases, oxygen may be used as an auxiliary), and if necessary, combined treatment with reductive bleaching treatment Is preferred.
[0024]
As a preferred multi-stage bleaching method of the non-dry hardwood bleached kraft pulp that is advantageously used in the practice of the present invention, chlorination (hereinafter abbreviated as symbol C) or ECF treatment (hereinafter abbreviated as symbol F) is applied as the preceding stage bleaching treatment. As the subsequent bleaching treatment, alkali treatment or extraction (hereinafter abbreviated as symbol E) is applied, and further hypochlorite bleaching treatment (hereinafter abbreviated as symbol H) or chlorine dioxide bleaching treatment (hereinafter abbreviated as symbol D). A method in which an alkaline peroxide bleaching treatment (hereinafter abbreviated as symbol P) is performed as necessary is advantageous. For example, “CEHDED”, “FEHDED”, “CEHDPD”, “CEHDEDP”, [FEHDEDP ”,“ CEHED ”,“ CEHPD ”,“ CEHEDP ”, [FEHEEDP],“ CEHEH ”,“ CEHEHP ”,“ FEHEHP ”, Methods such as “CEHPPHP”, “CEDED”, [FEHDED], and “CEEDDP” are useful.
[0025]
As a bleaching chemical for the non-dry hardwood bleached kraft pulp that is advantageously used in the practice of the present invention, chlorine gas or chlorine water is used for chlorine bleaching. Further, chlorine dioxide may be used in combination. It is advantageous to use caustic soda for the alkali treatment or extraction, but calcium hydroxide, ammonia and the like and mixtures thereof can be used. For hypochlorite bleaching, bleaching powder made by acting chlorine on solid powdered slaked lime, especially hypochlorous acid bleaching solution prepared by blowing chlorine into lime milk or dilute caustic soda solution industrially. So-called calcium-hypo bleaching solution and sodium-hypo bleaching solution are advantageously used. For chlorine dioxide bleaching, the Mathison method, the new Mathison method, the Elst method, C.I. I. Chlorine dioxide prepared by a hydrochloric acid system such as a sulfurous acid system such as the P method, a kesting method, a Nisso method, or a sorbet method is advantageously used. For alkaline peroxide bleaching, peroxides include hydrogen peroxide, sodium peroxide, peroxide bleaching solution (hydrogen peroxide, caustic soda, sodium silicate, and magnesium sulfate added as necessary. Inorganic or organic peroxides such as peracetic acid and t-butyl hydroperoxide and mixtures thereof are advantageously used, and alkalis include caustic soda, potassium hydroxide, aqueous ammonia, magnesium hydroxide, water Alkaline hydroxides or alkaline earth hydroxides such as calcium oxide and mixtures thereof are advantageously used. Ozone prepared from an ozone generator is advantageously used. The bleaching treatment may be performed under various conditions such as those described in “Pulp Processing and Bleaching” edited by the Paper and Pulp Technology Association (issued on January 27, 1968) and Japanese Patent Publication No. 58-43732. I can do it.
[0026]
In the present invention, the bleached pulp is preferably sent to a selection process, and the pulp is preferably cleaned using a cleaner, preferably a hydrocyclone cleaner. The final rejection rate with a cleaner is 0.02% by weight or more, preferably 0.05% by weight or more, per absolute dry pulp. Further, in the present invention, the pulp selected in the selection process is a slurry having a slurry form, specifically, a dry pulp concentration of usually 2 wt% to 10 wt%, preferably 3 wt% to 6 wt%. It is preferably sent to the beating process in the form. Also, in some cases, the pulp is concentrated by a suitable dewatering device, and the pulp dry concentration is less than 50% by weight of pulp concentrate or wet form pulp (therefore their dry water content is 50% by weight or more). As another example, it may be sent to the beating process by an appropriate transfer means such as a belt conveyor.
[0027]
The non-dry hardwood bleached kraft pulp used in the practice of the present invention is beaten and prepared so that the fiber length of the pulp is within a specific range measured for the pulp after beating before the addition of paper chemicals. It has been found that the effects of the present invention, in particular, the apparent glossiness of the image material and its print can be significantly improved by using. From this point of view, the non-dry hardwood bleached kraft pulp used in the practice of the present invention is useful when the fiber length is beaten in the range of 0.42 mm to 0.70 mm, but 0.45 mm to 0.65 mm. Beating in the range of 0.47 mm to 0.62 mm is more preferable, and beating in the range of 0.49 mm to 0.59 mm is particularly preferable. If the fiber length of the pulp is too short, the internal bond strength of the base paper becomes weak and the stiffness is lowered. On the other hand, if the fiber length of the pulp is too long, the effect of the present invention is hardly exhibited. In the present invention, the freeness of the pulp is preferably beaten in the range of 250 ml to 360 ml, more preferably beaten in the range of 280 ml to 330 ml. If the freeness of the pulp is too low, the papermaking suitability will be insufficient, the stiffness of the base paper will be low, and if the freeness of the pulp is too high, the formation of the base paper will tend to be poor. The freeness of the pulp as used in the present specification is the freeness (ml) measured for the pulp after beating according to TAPPI standard pulp test method No. T227m-58 “pulp freeness (freeness)”. )
[0028]
In the present invention, it is possible to preferably prepare by optimizing the balance between cutting beating and viscous beating as conditions for beating the pulp so that the fiber length and freeness of the pulp are in preferable ranges. Specifically, the beating beating ratio, beating time, pulp concentration, beating power, and other beating conditions were beaten under a series of experimental conditions, and the pulp fiber length and pulp of the collected pulp slurry It can be optimized by measuring the freeness.
[0029]
Various additives can be incorporated into the base paper used in the practice of the present invention when preparing the paper slurry. As sizing agent, fatty acid metal salt or fatty acid, alkyl ketene dimer emulsion described or exemplified in JP-B-62-7534, epoxidized higher fatty acid amide, alkenyl or alkyl succinic anhydride emulsion, rosin derivative, etc., dry paper Anionic, cationic or amphoteric polyacrylamide, polyvinyl alcohol, cationized starch, vegetable galactomannan, etc. Calcium, titanium oxide, etc., fixing agents such as water-soluble aluminum salts such as aluminum chloride and sulfuric acid, etc., pH regulators such as caustic soda, sodium carbonate, sulfuric acid, etc. -266537 Gazette etc. or exemplified coloring Fee, colored dye, that allowed to contain appropriately combining a fluorescent whitening agent is advantageous.
[0030]
Further, a composition comprising various water-soluble polymers or hydrophilic colloids or latexes, antistatic agents and additives is applied to the base paper used in the practice of the present invention by size press or tab size press or blade coating. It can be contained or applied by coating such as coating or air knife coating. As a water-soluble polymer or hydrophilic colloid, starch-based polymer, polyvinyl alcohol-based polymer, gelatin-based polymer, polyacrylamide-based polymer, cellulose-based polymer, etc. described or exemplified in JP-A No. 1-266537, as emulsions and latexes, Petroleum resin emulsion, emulsion or latex of copolymer comprising at least ethylene and acrylic acid (or methacrylic acid) as described or exemplified in JP-A-55-4027 and JP-A-1-80538, styrene -Natural chloride as an antistatic agent, such as emulsions or latexes of butadiene-based, styrene-acrylic-based, vinyl acetate-acrylic-based, ethylene-vinyl acetate-based, butadiene-methyl methacrylate-based copolymers and carboxy-modified copolymers thereof , Alkaline metal salts such as potassium chloride, alkaline earth metal salts such as calcium chloride and barium chloride, colloidal metal oxides such as colloidal silica, organic antistatic agents such as polystyrene sulfonate, etc. Kaolin, calcium carbonate, talc, barium sulfate, titanium oxide, etc. As pH regulators, hydrochloric acid, phosphoric acid, citric acid, caustic soda and other additives such as colored pigments, coloring dyes, and optical brighteners are appropriately combined. It is advantageous to contain or coat.
[0031]
In addition, as the base paper used in the practice of the present invention, the paper thickness non-uniformity index Rpy defined below is preferably 250 mV or less, more preferably 200 mV or less, and most preferably 150 mV or less. . The film thickness nonuniformity index Rpy referred to here is an electronic micrometer using a film thickness measuring instrument that moves a sample between two spherical styluses and measures the thickness variation of the sample as an electrical signal via the electronic micrometer. Under the condition that the sensitivity range is ± 15μm / ± 3V, the thickness variation in the paper making direction of the sample is measured by scanning at a constant speed of 1.5m / min in the paper making direction of the sample after zero adjustment. The signal value is subjected to fast Fourier transform using a Hanning window as a time window using an FFT analyzer, and a power spectrum (unit: mV) obtained by adding and averaging 128 times. ² ) And the power value in the frequency range of 2 Hz to 25 Hz is summed and multiplied by 2/3 to the power of 1/2 (unit: mV).
[0032]
As a method for producing a base paper having a film thickness nonuniformity index Rpy of 250 mV or less, which is preferably used in the practice of the present invention, specifically, appropriately hardened hardwood pulp is 30% by weight or more, preferably 50% by weight or more. Use. Specifically, for example, as the total pulp constituting the base paper, the fiber length of the pulp after beating is preferably 0.45 mm to 0.65 mm, more preferably 0.47 mm to 0.62 mm, and particularly preferably 0. Use hardwood kraft pulp beaten to .49mm to 0.59mm. It is preferable to use a paper making method suitable for the stock slurry to which the internal chemicals are added, and to make a base paper with a long net paper machine so that a uniform formation can be obtained. Specifically, for example, using a long web paper machine having an appropriate upper dewatering mechanism as described or exemplified in JP-A-61-284762, which gives an appropriate turbulence to the stock slurry, As a press, a multi-stage wet press, preferably a wet press of three or more stages, and a smooth paper roll at the final stage of the press part is combined with an appropriate paper making method so that a uniform texture can be obtained. The paper sheet is then subjected to calendering using a machine calendar, super calender, thermal calendar or the like after paper making, whereby a base paper having a film thickness nonuniformity index Rpy of 250 mV or less can be produced.
[0033]
As the base paper used in the practice of the present invention, the center plane average roughness SRa in the paper making direction at a cut-off value of 0.8 mm measured using a stylus type three-dimensional surface roughness meter on the front side of the base paper ( Hereinafter, the term “center surface average roughness SRa in the paper making direction at a cut-off value of 0.8 mm measured using a stylus type three-dimensional surface roughness meter on the front side of the base paper is simply referred to as center surface average roughness SRa”. Is preferably 1.50 μm or less, preferably 1.40 μm or less, more preferably 1.35 μm or less, and particularly preferably 1.25 μm or less. The center surface average roughness SRa at a cutoff value of 0.8 mm measured using a stylus type three-dimensional surface roughness meter in the present specification is defined by Equation 1.
[0034]
[Expression 1]

[0035]
In Equation 1, Wx represents the length in the X-axis direction (paper making direction) of the sample surface area, Wy represents the length in the Y-axis direction (direction perpendicular to the paper making direction) of the sample surface area, and Sa represents the sample surface. Represents the area of the area.
[0036]
As a method for producing a base paper having a center plane average roughness SRa of 1.50 μm or less that is preferably used in the practice of the present invention, specifically, as described above (paragraph 0027), an appropriate fiber length and Filter Use pulp that has been beaten so as to have a water level, perform multi-stage tension pressing in the middle of drying wet paper, and after making the base paper, use a machine calendar, super calendar, thermal calendar, etc. For example, machine calendar processing or / and thermal machine calendar processing is performed on the base paper as the first series of calendar processing, and then machine calendar processing is performed as necessary for the second and subsequent series of calendar processing. A base paper having a center plane average roughness SRa of 1.50 μm or less can be produced by performing a thermal soft calendering process described or exemplified in Japanese Utility Model Publication No. 4-110939. Also, various water-soluble polymers, hydrophilic colloids, or polymer latexes in the base paper or on the base paper are applied in a solid press amount of 1.0 g / kg by size press or tab size press, blade coating, air knife coating or the like. It is preferable to contain or coat m2 or more, particularly 2.2 g / m2 or more.
[0037]
The density of the base paper used in the practice of the present invention is 0.80 g / cm calculated excluding ash. ^Three ~ 1.15g / cm ^Three Is preferred, 0.85 g / cm ^Three ~ 1.05g / cm ^Three However, the present invention is not limited to these ranges. Further, regarding the thickness of the base paper used in the practice of the present invention, there is no particular deadline, but the basis weight is 40 g / m. ² ~ 250g / m ² Is useful, 70g / m ² ~ 220g / m ² Are preferred.
[0038]
The side (front side) on which the image forming layer of the base material for the image material support in the present invention is provided is coated with a resin layer containing a resin capable of forming a film. The back side of the base paper is preferably covered with a resin layer containing a resin capable of forming a film. The resin capable of forming a film is preferably a thermoplastic resin such as a polyolefin resin, a polycarbonate resin, a polyester resin, a polyamide resin, and a mixture thereof. Among them, the above-described polyolefin resin and / or polyester resin is preferable from the viewpoint of melt extrusion coating property. More preferred are polyethylene resins. Moreover, you may coat | cover with the resin layer which consists of an electron beam curable resin as described in Japanese Patent Publication No. 60-17104 gazette.
[0039]
The polyethylene resin for the front resin layer and the back resin layer preferably used in the practice of the present invention includes a low density polyethylene resin, a medium density polyethylene resin, a high density polyethylene resin, a linear low density polyethylene resin, and an ultra low density. So-called carboxy-modified polyethylene resin, which is a polyethylene resin, a copolymer of ethylene and an α-olefin such as propylene, butylene, a copolymer of ethylene and acrylic acid, acrylic acid ethyl ester, maleic anhydride, or a graft copolymer Etc, also autoclay The -Type resin, polyethylene resin by high-pressure radical polymerization using tubular reactors, polyethylene-based resin produced by polymerization using metallocene polymerization catalyst, metal catalyst other than metallocene using Ziegler method, Philips method, etc. Examples thereof include polyethylene resins polymerized and produced using the above and mixtures thereof. As those polyethylene-based resins and mixtures, those having various densities, melt flow rates (hereinafter, melt flow rates defined in JIS K 6760 are simply abbreviated as MFR), molecular weights, and molecular weight distributions can be used. Usually, the density of the resin component constituting the resin layer (as a mixture in the case of a mixture) is 0.90 to 0.97 g / cm. ^Three In the range of 0.1 g / 10 min to 50 g / 10 min, preferably MFR in the range of 0.3 g / 10 min to 40 g / 10 min can be used advantageously alone or in combination.
[0040]
Examples of the polyethylene resin polymerized and produced by the high-pressure method preferably used for the surface resin layer in the practice of the present invention include various types of long-chain branches produced by the high-pressure production method using an autoclave reactor, a tubular reactor, or the like. This is a polyethylene resin. Polyethylene resins polymerized and produced by these high-pressure methods include low-density polyethylene resins, medium-density polyethylene resins, copolymers with ethylene-based propylene, butylene and other α-olefins, carboxy-modified polyethylene resins, and the like. These are mixtures of various densities, MFRs, molecular weights, and molecular weight distributions. Usually, the density is 0.90 to 0.95 g / cm. ^Three And those having an MFR of 0.1 to 50 g / 10 min, preferably an MFR of 0.4 to 50 g / 10 min, can be used alone or in admixture of two or more.
[0041]
Examples of the polyethylene resin produced by polymerization using a metallocene polymerization catalyst particularly preferably used for the surface resin layer in the practice of the present invention include Japanese Patent Publication No. 3-502710, Japanese Patent Application Laid-Open No. 60-35006, As described or disclosed in 63-501369, JP-A-3-234717, JP-A-3-234718, etc., a metallocene such as zirconium or hafnium is preferably combined with methylaluminoxane or the like. A polymer produced by using a polymer having a higher catalytic activity as a polymerization catalyst. The polyethylene resins polymerized using these metallocene polymerization catalysts include ultra-low density polyethylene resin, low density polyethylene resin, medium density polyethylene resin, high density polyethylene resin, linear low density polyethylene resin, and ethylene as the main component. Copolymers with α-olefins such as propylene and butylene, carboxy-modified polyethylene resins, and the like, and mixtures thereof, which can be used in various densities, MFR, molecular weights, and molecular weight distributions. .87-0.97g / cm ^Three In the range of 0.05 to 500 g / 10 min, preferably 0.08 to 300 g / 10 min, can be used alone or in admixture of two or more.
[0042]
Examples of the polyethylene resin polymerized and produced using a metal polymerization catalyst other than the metallocene polymerization catalyst particularly preferably used for the surface resin layer in the practice of the present invention include various polyethylenes produced by polymerization using, for example, the Ziegler method and the Philips method. Based resins. Examples of polyethylene resins polymerized using metal polymerization catalysts other than those metal metallocene polymerization catalysts include ultra-low density polyethylene resins, low density polyethylene resins, medium density polyethylene resins, high density polyethylene resins, and linear low density polyethylene. Resins, copolymers of ethylene-based propylene, butylene and other α-olefins, carboxy-modified polyethylene resins, and mixtures thereof, and those having various densities, MFR, molecular weight, and molecular weight distribution can be used. Usually, the density is 0.87-0.97g / cm ^Three In the range of MFR of 0.05 to 500 g / 10 min, preferably 0.08 to 300 g / 10 min, can be used alone or in admixture of two or more.
[0043]
Polyester resins used in the practice of the present invention include polyethylene terephthalate resins, polybutylene terephthalate resins, polyester biodegradable resins and mixtures thereof, or mixtures of these with polyethylene resins, and various densities and limiting viscosities. [η] can be used. As a specific representative example, a polyester resin (trade name: NOVAPEX HS004, melting point 235 ° C., density 1.33 g / cm, manufactured by Mitsubishi Chemical Corporation) ^Three Intrinsic viscosity [η] 0.73 dl / g). Moreover, the mixture of a polyester resin and a polyethylene-type resin can be used advantageously. Examples thereof include a mixture of a copolymerized polyethylene terephthalate resin and a copolymerized polyethylene resin grafted with maleic acid (melting point 74 ° C.) (manufactured by Mitsubishi Kasei Co., Ltd., melting point 224 ° C.).
In addition, as the polycarbonate resin used in the practice of the present invention, those of various grades can be used. As a concrete representative example, polycarbonate resin manufactured by Mitsubishi Kasei Co., Ltd. (trade name: NOVAREX 7022A, density 1) .20g / cm ^Three MFR 12 to 16 g / 10 minutes, softening point 160 ° C. to 190 ° C.).
[0044]
The polyethylene resin for the back resin layer advantageously used in the practice of the present invention has an MFR of 10 g / 10 min to 40 g / 10 min, preferably 10 g / 10 min to 30 g / 10 min, and a density of 0.960 g / cm. ^Three 90 to 65 parts by weight of the above high-density polyethylene resin and MFR of 0.2 g / 10 min to 3 g / 10 min, preferably 0.2 g / 10 min to 1.5 g / 10 min, with a density of 0 .935g / cm ^Three A compound resin composition obtained by previously melting and mixing 10 parts by weight to 35 parts by weight of the following low density polyethylene resin or medium density polyethylene resin is preferable. The molecular weight distribution of the low-density polyethylene resin or medium-density polyethylene resin is preferably 10% by weight or more, particularly preferably 12% by weight or more, with a molecular weight of 500,000 or more. If the fraction of the resin having a molecular weight of 500,000 or more is less than 10% by weight, moldability, particularly neck-in, is undesirably increased. Here, the molecular weight was measured by Waters 150-C (Column: Tosoh GMH-XL HT 8 mmφ × 30 cm × 3, solvent: 1,2,4-trichlorobenzene, temperature: 135 ° C., flow rate: 1 ml / min)).
[0045]
The polyethylene resin for the back resin layer used in the practice of the present invention is preferably a compound resin prepared by melting and mixing in advance. As a method for preparing a compound resin by previously melting and mixing a low density polyethylene resin or a medium density polyethylene resin and a high density polyethylene resin, a simple melt mixing method, a multistage melt mixing method, or the like can be used. For example, by using an extruder, a twin screw extruder, a heated roll kneader, a Banbury mixer, a pressure kneader, etc., a predetermined amount of low density or medium density polyethylene resin and high density polyethylene resin, and if necessary, an antioxidant A method of adding various additives such as a lubricant, melting and mixing, and then pelletizing the mixture is advantageously used.
[0046]
The support for image material in the present invention is for the front resin layer when the resin capable of forming a film in the front resin layer and the back resin layer is a thermoplastic resin, preferably a polyolefin resin, particularly preferably a polyethylene resin. And a resin composition for the back resin layer is produced by a so-called melt extrusion coating method in which a running extruder is coated on a traveling base paper in the form of a film from its slit die. Usually, using a melt extruder on the traveling base paper, the melted resin composition is extruded from the slit die into a film, coated by casting, and pressure-bonded between a pressure roll and a cooling roll, It is produced in a series of steps of peeling from the cooling roll.
[0047]
As the surface resin layer of the support for image material in the present invention, the effect of the present invention can be obtained by a synergistic effect in combination with a base paper containing non-dry hardwood bleached kraft pulp by forming a multilayer structure of two layers or more. Has been found to be extremely prominent. That is, by making the surface resin layer of the support for image material in the present invention into a two-layer structure or a multilayer structure of more than that, the image material having the support and the apparent glossiness of the print can be remarkably improved. In addition, the present inventors have found that the releasability from the cooling roll during the production of the support can be remarkably improved, and hence the occurrence of uneven peeling can be eliminated, and therefore the support for image material can be produced stably at high speed.
[0048]
A particularly preferred support for an image material in the present invention has a multilayer structure having two or more surface resin layers, but a two-layer structure is preferable for efficiently achieving the object of the present invention. Further, the image material support having a surface resin layer having a multilayer structure of two layers or more is preferably one produced by a melt extrusion coating method. In the production, a so-called co-extrusion coating method in which two or more multilayer resin layers are simultaneously extrusion coated may be used, or a resin layer consisting of at least the lowermost layer and then a resin consisting of at least the uppermost layer. A so-called sequential extrusion coating system may be used in which the layers are sequentially melt extrusion coated at separate stations. In the present invention, a support for image material produced using a sequential extrusion coating method is particularly preferred.
[0049]
In the melt extrusion coating, the slit die is preferably a flat die such as a T-type die, an L-type die, or a fishtail die, and the slit opening diameter is preferably 0.1 mm to 2 mm. The multilayer coextrusion die may be any type such as a feed block type, a multi-manifold type, and a multi-slot type. Further, the temperature of the molten film is preferably 280 ° C. to 340 ° C. In that case, a temperature difference between the resin composition for the uppermost layer and the resin composition constituting the lower resin layer may be given. . For example, the temperature of the resin composition for the uppermost layer is made 5 to 10 ° C. lower than the temperature of the resin composition constituting the lower resin layer to improve the peelability of the resin layer from the cooling roll. I can do it.
[0050]
As the resin layer of the support for an image material particularly preferable in the present invention in which the surface resin layer has a multilayer structure, the uppermost resin layer (hereinafter sometimes simply referred to as the uppermost layer) and the lower resin are used. The layer (hereinafter sometimes simply referred to as the lower resin layer) may have the same physical properties and composition, or may be different. As the polyethylene resin preferably used for the uppermost layer and the lower resin layer, various kinds of density, MFR, molecular weight, molecular weight distribution, etc. as described above can be used alone or in combination, and their physical properties are the same. May be different or different.
[0051]
For example, as the polyethylene resin in the uppermost layer, the MFR (MFR as a mixture when two or more types are contained, hereinafter the same meaning) is used as the MFR of the polyethylene resin in the lower resin layer (two In the case of containing more than one species, MFR as a mixture, hereinafter the same meaning), higher, lower or the same can be used. For example, the polyethylene resin in the uppermost layer has an MFR of 5 g / 10 min to 20 g / 10 min, and the polyethylene resin in the lower resin layer has an MFR of 2 g / 10 min to 10 g / 10 min On the other hand, as the polyethylene resin in the uppermost layer, the MFR is 2 g / 10 min to 10 g / 10 min, and as the polyethylene resin in the lower resin layer, the MFR is 5 g / 10 min to 20 g / 10. Can be used, and those with the same MFR can be used.
[0052]
Further, as the polyethylene resin in the uppermost layer, the density (in the case where two or more types are contained, the density as a mixture, hereinafter the same meaning) is the density of the polyethylene resin in the lower resin layer (two In the case of containing more than one species, the density as a mixture, which is the same meaning below), higher, lower or the same can be used. For example, as a polyethylene resin in the uppermost layer, the density is 0.925 g / cm. ^Three ~ 0.970 g / cm ^Three As a polyethylene resin in the lower resin layer, the density is 0.870 g / cm ^Three ~ 0.925g / cm ^Three On the other hand, as the polyethylene resin in the top layer, the density is 0.870 g / cm ^Three ~ 0.925g / cm ^Three As a polyethylene resin in the lower resin layer, the density is 0.925 g / cm ^Three ~ 0.970 g / cm ^Three Can be used, and those with the same density can be used.
[0053]
Further, as the polyethylene resin in the uppermost layer, at least one of those whose melting point is higher, lower or the same as that of the polyethylene resin in the lower resin layer can be used. For example, the polyethylene resin in the uppermost layer can have a melting point of 115 ° C. or higher, and the polyethylene resin in the lower resin layer can have a melting point of less than 115 ° C., while the polyethylene resin in the uppermost layer can be used. As the polyethylene resin in the lower resin layer, those having a melting point of 115 ° C. or higher can be used, and those having the same melting point can be used.
[0054]
As the resin layer having a particularly preferable multilayer structure of the image material support in the present invention, the effects of the present invention, that is, the image material having the support and the effect of improving the glossiness of appearance of the print and the effect of improving the peelability are shown. From the standpoint that it can be remarkably exhibited, as the polyethylene resin in the uppermost layer, at least one kind whose density is higher than the density of the polyethylene resin in the lower resin layer is used, or the melting point is lower. Multi-layer structure using at least one kind higher than melting point of polyethylene resin in side resin layer, or using at least one kind higher in density and melting point than those of polyethylene resin in lower resin layer The resin layer is particularly preferable.
[0055]
Various additives can be contained in the front resin layer of the support for image material in the present invention and, if necessary, in the back resin layer. In order to improve the whiteness of the support and the sharpness of the image, Japanese Patent Publication No. 60-3430, Japanese Patent Publication No. 63-11655, Japanese Patent Publication No. 1-38291, Japanese Patent Publication No. 1-38292, It is preferable to include the titanium dioxide pigment described or exemplified in JP-A-1-05245. Further, in addition to titanium dioxide, white pigments such as zinc oxide, talc and calcium carbonate, release agents, fatty acid amides such as stearamide, arachidic acid amide, pigment dispersants and release agents, zinc stearate, Fatty acid metal salts such as calcium stearate, aluminum stearate, magnesium stearate, zinc palmitate, zinc myristate, calcium palmitate, hindered phenols, hindered amines, phosphorus-based, sulfur described or exemplified in JP-A-1-105245 Various antioxidants such as cobalt, blue pigments and dyes such as cobalt blue, ultramarine blue, ceria blue and phthalocyanine blue, magenta pigments and dyes such as cobalt violet, fast violet and manganese violet, JP-A-2-254440 Firefly described or illustrated Various additives such as a light brightener and an ultraviolet absorber can be appropriately combined and contained. These additives are preferably contained as a resin masterbatch or compound. In addition, from the viewpoint of effective improvement of print sharpness or whiteness or heat resistance, light resistance or releasability of the support for image material, white pigments such as titanium oxide, fluorescent whitening agents, coloring pigments, It is preferable that other additives such as a coloring dye, an antioxidant, an ultraviolet absorber, or a release agent are contained in a higher concentration in the uppermost layer than in the lower resin layer. In particular, the content of titanium dioxide pigment in the uppermost layer (as a proportion of the weight in the uppermost layer) is 7% by weight or more, further 9% by weight or more, still more 12% by weight or more, particularly 15% by weight or more. Is preferred.
[0056]
In practicing the present invention, it is preferable to subject the base paper to activation treatment such as corona discharge treatment and flame treatment before coating the base paper with the front and back resin compositions. Further, as described in JP-B-61-42254, a resin layer may be coated on the base paper that travels after the ozone-containing gas is sprayed on the molten resin composition on the side in contact with the base paper. In addition, the front and back resin layers are preferably coated on the base paper in a so-called tandem extrusion coating method, which is successively, preferably continuously, extrusion coated, and if necessary, the back resin layer may be two or more layers. You may coat | cover with the multilayer structure of these. Further, the surface resin layer surface of the support for image material can be processed into a glossy surface, a fine rough surface described in Japanese Patent Publication No. 62-19732, a matte surface or a silky surface, and the back resin layer is usually matte It is preferable to process the surface.
[0057]
As the coating thickness of the surface resin layer of the support for image material in the present invention, a range of 8 to 100 μm is useful, but a range of 12 to 60 μm is preferable, and a range of 18 to 40 μm is particularly preferable. Further, in the case of a multilayer structure in which the resin layer is a particularly preferable support for an image material according to the present invention and the resin layer is coated by sequentially melt extrusion coating a resin layer consisting of at least the lowermost layer and a resin layer consisting of at least the uppermost layer, The thickness of the resin layer comprising the lowermost layer is preferably 25% or more of the total resin layer thickness on the front side, preferably 39% or more from the viewpoint of the effect of improving the glossiness of the appearance of the image material and its print. The thickness is more preferable, and a thickness of 50% or more is particularly preferable, but is not particularly limited. Further, the base paper surface on the back side is preferably coated with a back resin layer mainly composed of a resin capable of forming a film, but the resin is preferably a polyethylene-based resin, and the coating thickness is a resin layer on the front side, In particular, it is preferable to set appropriately within the range where the curl balance is obtained. Generally, the range of 8 to 100 μm is useful, but the range of 12 to 60 μm is preferable.
[0058]
The surface resin layer surface of the image material support in the present invention is subjected to activation treatment such as corona discharge treatment and flame treatment, and then disclosed in JP-A-61-84643 and JP-A-1-92740. An undercoat layer as described or exemplified in Kaihei 1-102551, JP-A-1-66035, etc. can be applied. In addition, on the back resin layer surface of the image material support in the present invention, after applying an activation treatment such as a corona discharge treatment or a flame treatment, various back coat layers are coated for antistatic purposes. Can do. In addition, the back coat layer includes JP-B 52-18020, JP-B 57-9059, JP-B 57-53940, JP-B 58-56859, JP-A 59-214849, Inorganic antistatic agents, organic antistatic agents, hydrophilic binders, latexes, curing agents, pigments, surfactants and the like described or exemplified in Japanese Utility Model Publication No. 58-184144 can be contained in appropriate combinations.
[0059]
In the present invention, the image material support is coated with various photographic constituent layers, for color photographic paper, for black-and-white photographic paper, for phototypesetting paper, for copy photographic paper, for reversal photographic material, and for silver salt diffusion. It can be used for various applications such as transfer method negative, positive, and printing materials. For example, a silver chloride, silver bromide, silver chlorobromide, silver iodobromide, or silver chloroiodobromide emulsion layer can be provided. Multilayer silver halide color photographic constituent layers can be provided by incorporating color couplers in the silver halide photographic emulsion layer. Further, a photographic constituent layer for silver salt diffusion transfer method can be provided. As binders for these photographic constituent layers, hydrophilic polymer substances such as polyvinyl pyrrolidone, polyvinyl alcohol, and polysaccharide sulfate compounds can be used in addition to ordinary gelatin. The photographic composition layer can contain various additives. Examples include sensitizing dyes such as cyanine dyes and merocyanine dyes, chemical sensitizers such as water-soluble gold compounds and sulfur compounds, antifoggants or stabilizers such as hydroxy-triazolopyrimidine compounds and mercapto-heterocyclic compounds. Formalin, vinyl sulphone compounds, aziridine compounds as hardening agents, alkylbenzene sulphonate and sulfosuccinic acid ester salts as coating aids, dialkyl hydroquinone compounds as antifouling agents, other fluorescent whitening agents, improved sharpness A dye, an antistatic agent, a pH adjusting agent, a fogging agent, and a water-soluble iridium, a water-soluble rhodium compound, and the like can be contained in appropriate combinations during the formation and dispersion of silver halide.
[0060]
The photographic material according to the present invention can be exposed, developed, stopped, fixed, as described in “Photosensitive materials and handling methods” (Kyoritsu Shuppan, written by Goro Miyamoto, Photographic Technology Course 2) according to the photographic material. Processing such as bleaching and stabilization can be performed. The multilayer silver halide color photographic material may be processed with a developer containing a development accelerator such as benzyl alcohol, thallium salt or phenidone, or may be processed with a developer substantially free of benzyl alcohol. it can.
[0061]
The support for an image material in the present invention can be used as a support for various heat transfer type thermal transfer recording image receiving materials on which various heat transfer type heat transfer recording image receiving layers are coated. Synthetic resins used for these heat transfer type thermal transfer recording image receiving layers include polyester resins, polyacrylate resins, polycarbonate resins, polyvinyl acetate resins, polyvinyl butyral resins, styrene acrylate resins, vinyl toluene acrylate resins, and other ester bonds. Resin having urethane bond such as polyurethane resin, resin having amide bond such as polyamide resin, resin having urea bond such as urea resin, other polycaprolactam resin, styrene resin, polyvinyl chloride resin, vinyl chloride -Vinyl acetate copolymer resin, polyacrylonitrile resin, etc. are mentioned. In addition to these resins, mixtures or copolymers thereof can also be used.
[0062]
In addition to the above synthetic resin, a release agent, a pigment and the like may be added to the heat transfer type thermal transfer recording image receiving layer according to the present invention. Examples of the mold release agent include solid waxes such as polyethylene wax, amide wax, and Teflon powder, fluorine-based surfactants, phosphate ester-based surfactants, and silicone oils. Of these release agents, silicone oil is most preferred. As the silicone oil, an oily material can be used, but a curable type is preferable. Examples of the curable silicone oil include a reactive curable type, a photo curable type, and a catalyst curable type, and a reactive curable type silicone oil is particularly preferable. Examples of the reaction curable silicone oil include amino-modified silicone oil and epoxy-modified silicone oil. The amount of the reactive silicone oil added is preferably 0.1 to 20 wt% in the image receiving layer. As the pigment, extender pigments such as silica, calcium carbonate, titanium oxide, and zinc oxide are preferable. The thickness of the image receiving layer is preferably 0.5 to 20 μm, more preferably 2 to 10 μm.
[0063]
The support for image material in the present invention can be used as a support for various ink jet recording materials on which various ink image receiving layers are coated. These ink image-receiving layers can contain various binders for the purpose of improving the drying property of the ink, the sharpness of the image, and the like. Specific examples of such binders include various types of gelatin such as lime-processed gelatin, acid-processed gelatin, enzyme-processed gelatin, gelatin derivatives such as gelatin reacted with dibasic acid anhydrides such as phthalic acid, maleic acid, and fumaric acid. Ordinary polyvinyl alcohols of various saponification degrees, carboxy-modified, cation-modified and amphoteric polyvinyl alcohols and derivatives thereof, starches such as oxidized starch, cationized starch and etherified starch, cellulose derivatives such as carboxymethylcellulose and hydroxyethylcellulose , Polyvinylpyrrolidone, polyvinylpyridium halide, polyacrylic acid soda, acrylic acid / methacrylic acid copolymer salt, polyethylene glycol, polypropylene glycol, polyvinyl ether, alkyl vinyl ether / maleic anhydride Polymers, styrene / maleic anhydride copolymers and their salts, synthetic polymers such as polyethyleneimine, conjugated diene copolymer latexes such as styrene / butadiene copolymers and methyl methacrylate / butadiene copolymers, polyvinyl acetate , Vinyl acetate / maleic acid ester copolymer, vinyl acetate / acrylic acid ester copolymer, vinyl acetate polymer latex such as ethylene / vinyl acetate copolymer, acrylic acid ester polymer, methacrylic acid ester polymer, ethylene -Acrylic ester copolymer, acrylic polymer such as styrene / acrylic ester copolymer or latex of copolymer, vinylidene chloride copolymer latex, etc., or functional groups such as carboxyl groups of these various polymers Functional group-modified polymer latex with a monomer containing, Aqueous adhesives such as thermosetting synthetic resins such as lamin resin and urea resin, and synthetic resin adhesives such as polymethyl methacrylate, polyurethane resin, unsaturated polyester resin, vinyl chloride / vinyl acetate copolymer, polyvinyl butyral, alkyd resin, etc. Inorganic binders such as alumina sol and silica sol described or exemplified in Japanese Patent Publication No. 3-24906, Japanese Patent Application Laid-Open No. 3-281383, Japanese Patent Application No. 4-40725 can be given, and these can be used alone or in combination. And can be contained.
[0064]
The ink image-receiving layer of the ink jet recording material according to the present invention can contain various additives in addition to the binder. For example, as a surfactant, an anionic surfactant such as a long chain alkylbenzene sulfonate, a long chain, preferably a branched alkylsulfosuccinate, a polyalkylene oxide of a long chain, preferably a branched alkyl group-containing phenol Nonionic surfactants such as ethers, polyalkylene oxide ethers of long-chain alkyl alcohols, fluorinated surfactants described in Japanese Patent Publication No. 47-9303, US Pat. No. 3,589,906, etc. Silane coupling agents such as ethoxysilane and N-β (aminoethyl) γ-aminopropyltrimethoxysilane, polymer hardeners, active halogen compounds, vinyl sulfone compounds, aziridine compounds, epoxy compounds, acryloyl compounds, isocyanate compounds Hardener such as antiseptic As the agent, described in JP-A-1-102551 or exemplified P-hydroxybenzoic acid ester compounds, benzisothiazolone compounds, isothiazolone compounds, etc., JP-A 63-204251, JP-A 1-266537, etc. Or, examples of colored pigments, colored dyes, fluorescent whitening agents, hydroxymethane sulfonic acid sodium soda, P-toluene sulfinic acid soda, etc. as yellowing inhibitors, hydroxy-di-alkylphenyl groups in the 2-position as ultraviolet absorbers Benzotriazole compounds, etc., as antioxidants, polyhindered phenol compounds described or exemplified in JP-A-1-105245, etc., pencil writing agents, starch granules, barium sulfate, silicon dioxide and other organic or inorganic particles Fine particles with a diameter of 0.2 to 5 μm, or organopolysiloxanes described or exemplified in Japanese Examined Patent Publication No. 4-1337 Various additives such as octyl alcohol, silicon-based antifoaming agent, etc. can be appropriately combined and contained as a compound and pH adjuster such as caustic soda, sodium carbonate, sulfuric acid, hydrochloric acid, phosphoric acid, citric acid and the like.
[0065]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, the content of this invention is not restricted to an Example.
[0066]
Examples 1-6 and Comparative Examples 1-5
In the production process of hardwood bleached kraft pulp in the present invention, after cooking under the conditions described in JP-A-60-69649, unbleached kraft pulp is washed in the first stage washing process, and then oxygen delignification treatment (Processing conditions: pulp concentration is 15% by weight as the dry weight of unbleached pulp, caustic soda and oxygen are added at 1.5% and 1.0% by weight, respectively, per the dry weight of unbleached pulp, processing temperature and processing time. Was 110 ° C. and 45 minutes, respectively, and after the oxygen delignification treatment, it was washed in the second washing step. In the subsequent steps, “CEHDEDP” was used under the conditions described in JP-A-60-69649. Bleached hardwood bleached kraft pulp was carefully selected using a liquid cyclone cleaner, etc., in the refinement process, and the pulp concentration was 4% by weight as an absolute dry weight. The pulp fiber length was beaten so that the pulp fiber length was as described in Table 1. On the other hand, in the manufacturing process of comparative hardwood bleached kraft pulp, it was sent to the sheet machine after selection, and the moisture content was 15% by weight. The resulting pulp sheet was conveyed to a beating process and beaten so that the pulp fiber length was as described in Table 1.
[0067]
After beating, 100 parts by weight of pulp, 3 parts by weight of cationized starch, 0.2 parts by weight of anionized polyacrylamide, 0.4 parts by weight of an alkyl ketene dimer emulsion (as ketene dimer), and 0.5 parts of polyamide epichlorohydrin resin. A paper slurry was prepared by adding 4 parts by weight and an appropriate amount of fluorescent brightener, blue dye, and red dye. After that, a paper web was formed while giving appropriate turbulence on a long paper machine running the stock slurry at 200 m / min, and the linear pressure was adjusted in the range of 15-100 kgf / cm in the wet part. After performing a three-stage wet press, it was treated with a smoothing roll, followed by a two-stage tension press in which the linear pressure was adjusted in the range of 30 to 70 kgf / cm in the subsequent drying part, and then dried. Then, during drying, a size press solution consisting of 4 parts by weight of carboxy-modified polyvinyl alcohol, 0.05 parts by weight of optical brightener, 0.002 parts by weight of blue dye, 4 parts by weight of sodium chloride, and 92 parts by weight of water was 25 g / m ² Size-pressed, dried so that the final base paper moisture is 8% by weight in absolute dry moisture, machine calendered at a linear pressure of 70 kgf / cm, basis weight 170 g / m ² The density is 1.04 g / cm ^Three , Uneven film thickness finger A base paper for an image material support having a number Rpy of 180 mV was produced.
[0068]
Next, the base paper surface (back surface) opposite to the side on which the image forming layer is provided is subjected to corona discharge treatment, and then the following resin composition (R1) is applied to the back surface at a resin temperature of 315 ° C. based on a resin thickness of 20 μm. It was melt extrusion coated at a paper running speed of 200 m / min. At this time, as the cooling roll, a roll having a roughness with a center surface average roughness SRa of 1.15 μm after the coating of the following back layer was used. The cooling roll used was a cooling roll roughened by the liquid honing method, and operated at a cooling water temperature of 12 ° C.
[0069]
Resin composition (R1): High-density polyethylene resin (density 0.967 g / cm ^Three , MFR = 15 g / 10 min) 70 parts by weight and low density polyethylene resin (density 0.924 g / cm) ^Three , MFR = 0.6 g / 10 min) 30 parts by weight of a compound resin composition prepared by melting and mixing in advance using a melt extruder, and used as pellets.
[0070]
Subsequently, the surface of the base paper was subjected to corona discharge treatment, and then the surface resin layer (1) was coated with a low-density polyethylene resin having a density of 0.918 g / cm on the surface. ^Three , MFR = 8.5 g / 10 min, melting point 108 ° C., hereinafter abbreviated as low density polyethylene resin (R2)] 47.5 wt%, hydrous aluminum oxide (Al to titanium dioxide) ₂ O _Three 50% by weight of anatase-type titanium dioxide pigment and 2.5% by weight of zinc stearate surface-treated with 0.5% by weight) and an antioxidant, tetrakis [methylene-3 (3,5-di-tert-butyl- 4-hydroxyphenyl) propionate] Titanium dioxide pigment masterbatch consisting of 150 ppm of methane [hereinafter abbreviated as masterbatch (MB-1)] 17 parts by weight, low-density polyethylene resin (R2) 46.25% by weight, titanium dioxide pigment Titanium dioxide pigment masterbatch comprising 50% by weight, ultramarine (Daiichi Kasei Kogyo Co., Ltd., # 2000) 1.25% by weight, zinc stearate 2.5% by weight, and the above-mentioned antioxidant 150 ppm [hereinafter, masterbatch ( MB-2)] 8 parts by weight, autoclave low density polyethylene resin [density 0.920 g / cm ^Three , MFR = 4.5 g / 10 min, melting point 109 ° C., hereinafter abbreviated as low density polyethylene resin (R3) 57.6 parts by weight and Philips high density polyethylene resin [density 0.967 g / cm ^Three , MFR = 7.0 g / 10 min, melting point 130 ° C., hereinafter abbreviated as high density polyethylene resin (R4)] 17.4 parts by weight of a resin composition having a resin temperature of 315 ° C. and a thickness of 28 μm Using a melt extruder at a running speed of 200 m / min, melt extrusion coating was performed with a linear cooling roller and press roll pressure of 40 kgf / cm. Note that the melt extrusion coating of the front and back polyethylene resins was performed by a so-called tandem system in which sequential melt extrusion coating was performed. At that time, the surface of the resin layer containing the titanium dioxide pigment of the resin-coated paper was processed into a glossy surface.
[0071]
Separately, after corona discharge treatment on the surface of the base paper, as the surface resin layer (2), as the lower resin layer on the surface, the same resin composition as the surface resin layer (1) with a thickness of 14 μm, as the upper resin layer The same resin composition as the surface resin layer (1) with a thickness of 14 μm is used as a mirror cooling roll and a press roll using a two-layer co-extruder at a resin temperature of 315 ° C. and a base paper running speed of 200 m / min. The resin coating was carried out in the same manner as in the case of coating the surface resin layer (1) except that the two-layer simultaneous extrusion coating was performed at a linear pressure of 40 kgf / cm.
[0072]
Separately, after the corona discharge treatment on the surface of the base paper, as the surface resin layer (3), the same resin composition as the surface resin layer (1) having a thickness of 14 μm is formed on the surface, and the upper resin layer. As for the surface resin layer (1) having a thickness of 14 μm, a melt extruder is used in a separate station in the order of the lower layer and then the upper layer at a base paper traveling speed of 200 m / min at each resin temperature of 315 ° C. The resin coating was carried out in the same manner as in the case of coating the surface resin layer (1) except that sequential extrusion coating was carried out at a linear pressure of 40 kgf / cm between the mirror cooling roll and the press roll.
[0073]
Further, between the processing of the front and back resin layers and winding up, the back resin layer surface of the resin-coated paper was subjected to on-machine application of the following back layer coating liquid after corona discharge treatment. As dry weight, it was composed of colloidal silica: styrene latex = 1: 1, and polystyrene sodium sulfonate 0.021 g / m. ² The back layer coating solution containing an appropriate amount of coating aid, etc. as a latex component (calculated by solid weight) is 0.21 g / m. ² The coating amount was set to become.
[0074]
After coating the back layer and before winding the resin-coated paper, the resin surface on the front side was subjected to corona discharge treatment to give 1.2 g of lime-processed gelatin, low molecular weight gelatin (Nitta Gelatin Co., Ltd., P-3226). ) 0.3g, 0.3g of 10wt% methanol solution of butyl paraoxybenzoate and 0.45g of 5wt% mixture of methanol and water of sulfosuccinic acid-2-ethylhexyl ester salt, prepared to 100g with water The undercoating solution with the above composition was coated with a gelatin coating amount of 0.06 g / m. ² The support for image material was obtained by applying on-machine coating uniformly.
[0075]
As an evaluation method of the peelability from the cooling roll of the surface resin layer when manufacturing each image material paper support, it was obtained while visually observing the irregularity of the overall peel during the support manufacture. The surface state on the front side of the support for image material was observed with oblique light, and the degree of occurrence of peeling unevenness was visually judged, and a 10-stage grade evaluation was performed. The evaluation criteria (the larger the grade value, the better the peelability, the smaller the grade value, the worse the peelability) are as follows.
[0076]
Grades 10 to 9: The peeling from the cooling roll has no irregularity, the occurrence of peeling unevenness is little or no, and the peelability is very good.
Grade 8 to 7: Peeling from the cooling roll has almost no irregularity, occurrence of peeling unevenness is slight, and peelability is good.
Grade 6 to 5: Peeling from the cooling roll shows slight irregularity and peeling unevenness is slightly generated, but there is no practical problem.
Grade 4-1: Peeling from the cooling roll shows irregularity, and many peeling nonuniformities occur, which is a practical problem.
[0077]
Next, as a method for evaluating the glossiness of the appearance of a photographic print having a support for image material, evaluation was performed by the method described below.
[0078]
A blue-sensitive emulsion layer containing a yellow coloring coupler, an intermediate layer containing a color mixing inhibitor, a green-sensitive emulsion layer containing a magenta coloring coupler, and an ultraviolet absorber in this order adjacent to the undercoat layer of the image material support. An ultraviolet absorbing layer containing, a red sensitive emulsion layer containing a cyan coloring coupler, and a protective layer are coated with an E-bar for multilayer coating, and the total amount of gelatin is 7 g / m. ² A color photographic paper was created. Each color-sensitive emulsion layer is 0.6 g / m with silver nitrate. ² In addition to gelatin necessary for the formation, dispersion and film formation of silver halide, an appropriate amount of antifoggant, sensitizing dye, coating aid, hardener, thickener and Contains an appropriate amount of filter dye.
[0079]
Next, the prepared color photographic paper was stored at 35 ° C. under normal humidity for 5 days, then the group photo was baked, subjected to development, bleaching / fixing, stable development, and then dried to prepare a photographic print. Separately, white solid (unexposed) and black solid (black color) baked samples were also prepared. In addition, a series of processes of exposure, development, and drying were performed by an automatic printer and an automatic developing machine. The color development processing was performed in the order of color development (45 seconds) → bleaching / fixing (45 seconds) → stable (90 seconds) → drying.
[0080]
About the obtained group photo, white solid and black solid photo prints, the glossiness of the appearance of the photo prints was visually evaluated comprehensively by 10 monitors.
[0081]
The evaluation criteria for the apparent glossiness of photographic prints are as follows.
A: The glossiness of appearance is extremely high.
A to B: Appearance glossiness is quite high.
○: Appearance glossiness is higher.
○ to □: Appearance glossiness is high.
□: Appearance gloss is slightly high.
Δ: Appearance of gloss is somewhat low, but practical.
X: The glossiness of appearance is low, and there is a problem in practical use.
[0082]
The obtained results are shown in Table 1.
[0083]
[Table 1]

[0084]
From the results shown in Table 1, the substrate for imaging material in the present invention, which uses paper containing hardwood bleached kraft pulp sent to the beating process and beaten without making hardwood bleached kraft pulp after production, as a substrate ( It can be seen that Examples 1 to 6) are excellent supports for image materials that have high glossy appearance of photographic prints, good releasability, and no occurrence of uneven peeling.
[0085]
In particular, it is well understood that a support for image material using pulp having a fiber length in the range of 0.45 mm to 0.65 mm is preferable from the viewpoint of improving the glossiness of appearance of photographic prints (Example 1 and 4. Comparison between Examples 2 and 5 and Examples 3 and 6. In particular, it is well understood that the support for image material in which the surface resin has a multilayer structure is preferable from the viewpoint of the effect of improving the glossiness and peelability of the photographic print (Example 1 and Example 2 or 3 and Example). Comparison of Example 4 with Example 5 or 6). Furthermore, from the viewpoint of the effect of improving the glossiness and peelability of the appearance of photographic prints, a support for image materials in which the surface resin layer has a multi-layer structure in a sequential manner (which is equivalent to the sequential melt extrusion coating method) Examples 3 and 6) are more preferable, and a support for an imaging material in which a pulp having a fiber length in the range of 0.45 mm to 0.65 mm is used and the surface resin layer is formed into a multilayer structure in a sequential manner (Example 3) However, it is clear that it is most preferable.
[0086]
On the other hand, the support for imaging materials outside the present invention (Comparative Examples 1 to 5), which uses paper using dry pulp having an absolute dry moisture content of less than 50% as a substrate, has a low gloss on the appearance of photographic prints. It is clear that there is a problem. Even when the surface resin layer has a multilayer structure by the sequential method (Comparative Example 3), it can be seen that the effect of improving the apparent glossiness is not sufficient and the effectiveness of the present invention is clear (compared with Example 3). Comparison of Example 3).
[0087]
Examples 7-12 and Comparative Example 6
It implemented like Example 3 except using the pulp of the structure of Table 2 instead of the pulp used in Example 3. FIG.
[0088]
The obtained results are shown in Table 2.
[0089]
[Table 2]

[0090]
In Table 2, (P1) is the pulp used in Example 3, and (P2) is the pulp used in Comparative Example 3. The pulp was beaten separately or co-beaten so that the fiber length of the constituted pulp was 0.55 mm.
[0091]
From the results of Table 2, the content of the non-dry hardwood bleached kraft used in the practice of the present invention in the base paper is based on the total pulp constituting the base paper in terms of the effect of improving the glossiness of the appearance of photographic prints. Thus, it can be seen that 20% by weight or more is useful in terms of absolute dry weight%, preferably 40% by weight or more, more preferably 60% by weight or more, and particularly preferably 80% by weight or more.
[0092]
Examples 13-15 and Comparative Examples 7-8
It implemented similarly to Example 2 except using the following pulp (P1)-(P5) instead of the pulp used in Example 2. FIG.
Pulp (P1): Pulp used in Example 2, a pulp in the form of a slurry having an absolute dry weight of 4% and a pulp concentration of 4% by weight.
Pulp (P2): Pulp used in Comparative Example 2, dry pulp having an absolutely dry moisture content of 15% by weight.
Pulp (P3): A wet pulp produced in the same manner as pulp (P2) and having an absolutely dry moisture content of 45% by weight.
Pulp (P4): Pulp concentrate having an absolute dry water content of 60% by weight, which is bleached, finely selected and then pressed with a filter and a press (roll press and screw press).
Pulp (P5): Pulp concentrate produced in the same manner as pulp (P4) and having an absolute moisture content of 75% by weight.
[0093]
The obtained results are shown in Table 3.
[0094]
[Table 3]

[0095]
From the results in Table 3, the paper containing hardwood bleached kraft pulp that was sent to the beating process and beaten without making hardwood bleached kraft pulp after production into dry pulp or wet pulp with a moisture content of less than 50% by weight. It is well understood that the support for image materials (Examples 13 to 15) in the present invention using as a substrate is an excellent support for image materials having a high gloss appearance. Further, as the pulp used in the practice of the present invention, those having an absolute dry moisture content of 50% by weight or more are useful, but those having 75% by weight or more are preferable, and the pulp concentration is 10% by weight in terms of absolute dry weight%. It can be seen that the following slurry forms are particularly preferred.
[0096]
Examples 16-18 and Comparative Examples 9-10
It implemented similarly to Example 3 except using the pulp (P1)-(P5) used in Examples 13-15 and Comparative Examples 7-8 instead of the pulp used in Example 3. FIG.
[0097]
Table 4 shows the obtained results.
[0098]
[Table 4]

[0099]
From the results of Table 4, including hardwood bleached kraft pulp that was sent to the beating process and beaten, without making hardwood bleached kraft pulp into dry pulp or wet pulp having an absolute dry moisture content of less than 50% by weight after production. The support for image material according to the present invention (Examples 16 to 18) using paper as a substrate is an excellent image material having a high glossy appearance of photographic prints, good releasability and no occurrence of uneven peeling. It can be clearly seen that this is a support for use. Further, as the pulp used in the practice of the present invention, those having an absolute dry moisture content of 50% by weight or more are useful, but those having 75% by weight or more are preferable, and the pulp concentration is 10% by weight in terms of absolute dry weight%. It can be seen that the following slurry forms are particularly preferred.
[0100]
In addition, from the comparison between Table 3 and Table 4, in the present invention, from the viewpoint of the effect of improving the glossiness of appearance of a photographic print and the effect of improving the peelability, an image material in which the surface resin layer is formed into a multilayer structure in a sequential manner. It can be clearly seen that the support for Examples (Examples 16 to 18) is most preferable.
[0101]
Examples 19-27
As the type of pulp, the same pulp (P1) as in Example 2 was used, but the same procedure as in Example 2 was performed except that the pulp was beaten so that the fiber length of the pulp was as shown in Table 5.
[0102]
The results obtained are shown in Table 5.
[0103]
[Table 5]

[0104]
In addition, as a method of evaluating the waist strength of the image material, for a color photographic print of 13 cm x 18 cm, the edge of the color photographic print is shaken up and down by 10 monitors, and the waist strength by touch feeling is evaluated. did. Evaluation criteria are as follows: ○: waist is extremely or fairly strong, ○ to □: waist is strong, □: waist is slightly strong, △: waist is slightly weak, but practical to some extent, x: waist is weak, practical The problem represents some degree.
[0105]
From the results of Table 5, the non-dry hardwood bleached kraft pulp used in the practice of the present invention has a fiber length of 0.45 mm to 0.65 mm in terms of the glossiness of the appearance of the photographic print and the strength of the waist of the image material. It is well understood that the range of 0.47 mm to 0.62 mm is more preferable, and the range of 0.49 mm to 0.59 mm is particularly preferable.
[0106]
Examples 28-34
Instead of the resin composition for the upper layer or the lower layer for the surface resin layer (3) used in Example 3, the following resin compositions (3UA) to (3UD) or (3LE) to (3LG) Example 3 was carried out in the same manner as in Example 3 except that the combination was used and the running speed of the base paper was set to 300 m / min.
[0107]
(Resin composition for upper layer): (3UA) to (3UD)
Resin composition (3UA): 17 parts by weight of masterbatch (MB-1) used in Example 3, 8 parts by weight of masterbatch (MB-2) used in Example 3, and low-density polyethylene used in Example 3 A resin composition comprising 75 parts by weight of a resin (R3).
[0108]
Resin composition (3UB): The same upper layer resin composition as used in Example 3 (content of high-density polyethylene resin relative to all resin components in the upper layer, 20.1% by weight).
[0109]
Resin composition (3UC): 17 parts by weight of master batch (MB-1), 8 parts by weight of master batch (MB-2), 40.2 parts by weight of low density polyethylene resin (R3) and 34 parts of high density polyethylene resin (R4) A resin composition comprising 0.8 parts by weight (content of high-density polyethylene resin based on all resin components in the upper layer, 40.1% by weight).
[0110]
Resin composition (3UD): 21 parts by weight of master batch (MB-1), 9 parts by weight of master batch (MB-2), 53.1 parts by weight of low density polyethylene resin (R3) and 16 parts of high density polyethylene resin (R4) A resin composition comprising 0.9 parts by weight (content of high-density polyethylene resin based on all resin components in the upper layer, 20.1% by weight).
[0111]
(Resin composition for lower layer): (3LE) to (3LG)
Resin composition (3LE): The same lower layer resin composition as used in Example 3.
[0112]
Resin composition (3LF): Density 0.924 g / cm ^Three , MFR 4.5 g / 10 min, melting point 111 ° C., autoclave low density polyethylene resin.
[0113]
Resin composition (3LG): Density 0.924 g / cm ^Three Tubular low density polyethylene resin with MFR of 3.0 g / 10 min and melting point of 111 ° C.
[0114]
The results obtained are shown in Table 6.
[0115]
[Table 6]

[0116]
From the results shown in Table 6, among the image material supports having a multilayered surface resin layer, which is a preferred image material support in the present invention, the effect of improving the glossiness and peelability of the appearance of photographic prints. From the above, it can be seen that it is preferable that the uppermost layer contains at least one resin having a higher density or melting point than the resin in the lower resin layer. In addition, even if the content ratio of additives such as titanium dioxide pigment, color pigment, release agent, antioxidant, etc. in the resin layer below the uppermost layer is lower than the content ratio of the additive in the uppermost layer, It is well understood that the present invention is economically advantageous without any problem.
[0117]
Examples 35-38
In Example 32, when the surface resin layer was sequentially melt-extruded and coated, the resin temperature of the upper layer and lower layer resin compositions was the same as that of Example 3 except that the resin temperatures shown in Table 7 were used.
[0118]
The results obtained are shown in Table 7.
[0119]
[Table 7]

[0120]
From the results shown in Table 7, in the present invention, the temperature of the resin composition for the uppermost layer is set in the melt-extrusion coating of the resin composition for the surface resin layer having a multi-layer structure in view of the effect of improving the peelability. It is well understood that the temperature is preferably lower than the temperature of the resin composition constituting the lower resin layer.
[0121]
Examples 39-43
In Example 32, it carried out similarly to Example 32 except having set it as the coating thickness of Table 8 as coating thickness of the upper layer of a surface resin layer, and a lower layer.
[0122]
Table 8 shows the obtained results.
[0123]
[Table 8]

[0124]
From the results shown in Table 8, among the image material supports in which the surface resin layer has a multilayer structure, which is a preferable support for image materials in the present invention, the effect of improving the glossiness and peelability of the appearance of photographic prints. Therefore, the thickness of the resin layer comprising at least the lowest layer is preferably 25% or more of the total resin layer thickness, more preferably 39% or more, and particularly preferably 50% or more. I understand well.
[0125]
Examples 44-46
Instead of the resin composition for the upper layer and the lower layer for the surface resin layer (2) used in Example 2, the resin composition (3UD) is used as the resin composition for the upper layer and the resin composition for the lower layer. The same procedure as in Example 2 was performed except that the resin composition (3LF) was used and the running speed of the base paper was changed to the running speed shown in Table 9.
[0126]
Table 9 shows the obtained results.
[0127]
Examples 47-49
In Example 32, the same operation as in Example 32 was performed except that the traveling speed of the base paper was changed to the traveling speed described in Table 9.
[0128]
Table 9 shows the obtained results.
[0129]
[Table 9]

[0130]
The results of Table 9, ie, Examples 44 and 47 (each traveling speed of the base paper 200 m / min), Examples 45 and 48 (each traveling speed of the base paper 250 m / min), and Examples 46 and Example 49 (each traveling speed of the base paper 300 m / min), the higher the traveling speed of the base paper (that is, the manufacturing speed of the image material support), that is, the traveling speed of the base paper is In the case of 200 m / min or more, further 250 m / min or more, particularly 300 m / min or more, from the viewpoint of the effect of improving the glossiness of appearance of the photographic print and the unevenness of peeling, among the supports for image materials in the present invention. It can be seen that a support for image material in which the surface resin layer has a multilayer structure by the sequential melt extrusion coating method is particularly preferable. Further, the image material support is a particularly excellent image material support that can obtain an image material having a high gloss appearance and a print thereof, does not cause uneven peeling, and can be stably produced at high speed. I understand well.
[0131]
Example 50
Instead of the multilayer silver halide color photographic constituting layer, the following ink image-receiving layer was applied on the image material support of Example 3 to prepare an ink jet recording material. As a result, the inkjet recording material had a high gloss appearance and no uneven gloss, and the image material support was excellent.
[0132]
The ink image-receiving layer is composed of 30 g of 10% gelatin aqueous solution of alkali-processed gelatin having a molecular weight of 70,000, sodium carboxymethyl rose (degree of etherification: 0.7 to 0.8, viscosity of 2% aqueous solution by B-type viscometer) 37.5 g of 8 wt% aqueous solution of 5 cp or less), 0.3 g of 5 wt% methanol solution of epoxy compound (NER-010 manufactured by Nagase Sangyo Co., Ltd.), 5 of methanol and water of sulfosuccinic acid-2-ethylhexyl ester salt A coating solution composed of 0.5 g of a weight% mixed solution and 31.7 g of pure water is 7 g / cm in solid content. ² It was formed by coating.
[0133]
【The invention's effect】
According to the present invention, it is possible to provide an image material having a high gloss appearance and no gloss unevenness and a print thereof, and has good peelability from a cooling roll during the production of a support, and therefore, high-speed and stable production. It is possible to provide an excellent resin-coated paper-type support for image material using paper as a substrate.

Claims (13)

Paper substrate comprising natural pulp as a main component, and a paper substrate on which one of the image forming layers is provided is a support for an image material coated with a resin layer containing a film-forming resin, and is a hardwood bleaching craft. The kraft pulp sent to the beating process and beaten without being made into dry pulp or wet pulp having an absolute dry moisture content of less than 50% by weight after manufacturing the pulp is 20% by dry weight in the paper substrate. A support for imaging materials, containing at least wt% .   2. The support for imaging material according to claim 1, wherein the hardwood kraft pulp before being sent to the beating step is in the form of a slurry having a pulp concentration of 10% by weight or less by absolute dry weight%. The support for an image material according to claim 1 or 2 , wherein the fiber length defined below of the hardwood bleached kraft pulp after beating is 0.45 mm to 0.65 mm.
Fiber length of pulp: Regarding the pulp after beating, JAPAN TAPPI paper pulp test method no. 52-89 “Paper and Pulp Fiber Length Test Method” measured in accordance with the length weighted average fiber length (mm). Resin layer, according to claim 1, 2 or 3 images material support according those consisting of the bottom and top layers of at least two layers. 5. The support for imaging material according to claim 4 , wherein the resin layer is coated by a sequential extrusion coating method in which at least a resin layer comprising the lowermost layer and a resin layer comprising at least the uppermost layer are successively melt extrusion coated. . 6. The image material support according to claim 5 , wherein the thickness of the resin layer comprising at least the lowermost layer is 25% or more of the thickness of the entire resin layer. The resin layer is coated by a melt extrusion coating method under the condition that the temperature of the resin composition for the uppermost layer is lower than the temperature of the resin composition constituting the lower resin layer , 5. The support for image material according to 5 or 6 . The image according to claim 4, 5, 6 or 7 , wherein the uppermost layer contains at least one resin having a higher density or melting point than at least one resin contained in the resin layer below the uppermost layer. Material support. The support for an image material according to claim 4, 5, 6, 7 or 8 , wherein the content of the additive in the uppermost layer is higher than the content of the additive in the lower resin layer. The support for an image material according to claim 9 , wherein the additive is a white pigment, a coloring pigment, a coloring dye, a fluorescent brightener, an antioxidant, or a release agent. The support for an image material according to claim 10 , wherein the white pigment is a titanium dioxide pigment. The running speed of the paper substrate when the at least two resin layers are coated on the paper substrate is 200 m 2 / min or more, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 11 The support for image materials described. The paper substrate on the side opposite to the side on which the image forming layer is provided is coated with a resin layer containing a resin capable of forming a film, wherein: 1, 2, 3, 4, 5, 6, 7, 8 9. A support for imaging material according to 9, 10, 11 or 12.