JP3951550B2

JP3951550B2 - Method for preventing deterioration of printed matter and treatment liquid

Info

Publication number: JP3951550B2
Application number: JP2000116797A
Authority: JP
Inventors: 正也柴谷; 弘幸大西
Original assignee: Seiko Epson Corp
Current assignee: Seiko Epson Corp
Priority date: 2000-04-18
Filing date: 2000-04-18
Publication date: 2007-08-01
Anticipated expiration: 2020-04-18
Also published as: JP2001300415A

Description

【０００１】
【発明の属する技術分野】
本発明は、印刷物、特にインクジェット記録された印刷物の劣化防止方法及び該劣化防止方法に用いる処理液に関する。
【０００２】
【従来の技術及び発明が解決しようとする課題】
近年のインクジェット記録技術の革新的な進歩により、インクジェット記録により記録媒体に出力される画像は高品位化しており、銀塩写真に匹敵する高画質の画像の出力が可能となっている。しかし、高画質の画像の出力に用いられるインクジェット記録用のインクである染料インクは、紫外光や可視光、水分及び窒素酸化物ガスやオゾンガス等により経時的に変退色し易いという欠点を有する。このため、染料インクを用いてインクジェット記録された印刷物は、耐光性、耐水性及び耐ガス性に劣り、室内の壁に貼っておく等の通常の環境下において変色等の記録画像の劣化が起こる等、保存性（劣化防止）の点で未だ銀塩写真には及ばない。
【０００３】
また、インクジェット記録用媒体としては、非晶質シリカ等の微小な多孔質材料を含有するインク受容層を有する、いわゆる吸収型が主流であり、画像の高画質化追究のため、該多孔質顔料として、更に微小化したものが用いられる傾向にある。しかし、多孔質顔料を更に微小化すると、それに比例して比表面積が大きくなるため、インク受容層中の多孔質顔料と外気との接触性が高まり、その結果、印刷物の保存性、特に耐ガス性が低下するおそれがある。
【０００４】
また、近年のインクジェット用記録媒体自体は、耐水性はかなり満足し得る水準となったものの、その耐光性及び耐ガス性については依然課題となっている。
インクジェット用記録媒体の耐光性及び耐ガス性向上の技術としては、例えば、インクジェット用記録媒体を構成するインク受容層自体の耐光性や耐ガス性の向上を図ったもの（特開平９−２５４５２６号公報、特開平８−１６４６６４号公報、特開平５−２２１１１５号公報及び特開平７−２４６７６９号公報等参照）や、画像表面に耐光性や耐ガス性を有するフィルム、樹脂層等を積層したもの（特開平８−２５２９８５号公報、特開平８−２５２８８３号公報、特開平５−３１８９４３号公報、特開平８−１７４９８９号公報、特開平８−２０７４２９号公報及び特開平９−１７４９９５号公報等参照）等の技術があるが、何れもインクジェット用記録媒体に十分な耐光性及び耐ガス性を付与できない。
【０００５】
上述の通り、染料インクは、紫外光や可視光及び水分並びに窒素酸化物ガス、Ｈ₂Ｓガス、硫黄酸化物ガス及びオゾンガス等により経時的に変退色し易いという欠点を有しており、また、インクジェット用記録媒体は、耐光性及び耐ガス性が低いという欠点を有している。このため、該インクジェット用記録媒体に、該染料インクによりインクジェット記録された印刷物は、特に、耐光性及び耐ガス性の点で問題がある。
【０００６】
従って、本発明の目的は、印刷物に簡単な処理を施すだけで、印刷物の劣化防止、特に印刷物の耐光性及び耐ガス性を向上させて、紫外光や可視光、酸化性ガス等による該印刷物の変退色を防止することができる印刷物の劣化防止方法を提供することにある。
【０００７】
本発明者らは、耐水性基材上にインク受容層を設けてなる記録媒体に、染料インクにより画像及び／又は文字を形成した印刷物を、特定の処理液、詳しくは特定の樹脂を分散状態で含有する処理液で処理することにより、前記目的を達成し得ることを知見した。
【０００８】
【課題を解決するための手段】
本発明は、上記知見に基づきなされたもので、耐水性基材上にインク受容層を設けてなる記録媒体に、染料インクにより画像及び／又は文字を形成した印刷物を、処理液で処理する印刷物の劣化防止方法であって、前記処理液は、樹脂、耐光性向上剤及びインク定着剤を含有する該樹脂の水系分散液であり、その最低造膜温度が７０℃以上であり、前記樹脂は、印刷物［記録媒体における耐水性基材が、温度２０℃、相対湿度９０％の環境下における酸素透過率３０ｃｃ／（ｍ² ・Ｄ・ａｔｍ）以上の耐水性紙であり、そのインク受容層に染料インクにより画像の形成された印刷物］の画像の表面に該樹脂を塗工量１５ｇ／ｍ² で塗工することにより、該印刷物の温度２０℃、相対湿度９０％の環境下における酸素透過率を１０ｃｃ／（ｍ² ・Ｄ・ａｔｍ）以下にし得る樹脂であり、前記処理液による処理が、処理前の前記印刷物を前記処理液に浸積する浸積工程と、該浸積工程を経た前記印刷物を、前記水系分散液の最低造膜温度未満の温度で加熱して予備乾燥する予備乾燥工程と、該予備乾燥工程を経た前記印刷物の画像及び／又は文字が形成された一面にフィルムを接着させ、且つ前記水系分散液の最低造膜温度以上の温度で該印刷物を加熱して乾燥するフィルム接着工程と、前記印刷物から前記フィルムを剥離するフィルム剥離工程とを備える印刷物の劣化防止方法を提供するものである。
【０００９】
【発明の実施の形態】
以下、本発明の印刷物の劣化防止方法の好ましい実施形態について図１及び図２を参照しながら説明する。
先ず、本実施形態の劣化防止方法の対象となる印刷物１０について説明する。
印刷物１０は、図１に示すように、耐水性基材２上にインク受容層３を設けてなる記録媒体１に、染料インクにより画像及び／又は文字（図示せず）を形成してなるものである。印刷物１０を構成する記録媒体１及び前記染料インクは、この種の印刷物におけるものと同様である。
【００１０】
記録媒体１を構成する耐水性基材２としては、耐水性を有し、液処理工程により伸縮し難いものが用いられ、例えば、サイズ処理が施された紙、ポリエチレン、ポリプロピレン、ポリエステル等を紙にコートしたレジンコート紙、バライタ紙やＲＣペーパー等の写真用基材、ポリエチレンテレフタレート、ポリエチレン、ポリプロピレン等の熱可塑性樹脂フィルム、合成紙、合成繊維で形成されたシート状物等が挙げられる。
【００１１】
耐水性基材２の温度２０℃、相対湿度９０％の環境下における酸素透過率は、耐ガス性向上の観点から、好ましくは５０ｃｃ／（ｍ² ・Ｄ・ａｔｍ）以下、更に好ましくは３０ｃｃ／（ｍ² ・Ｄ・ａｔｍ）以下である。尚、酸素透過率の測定方法については後述する。
【００１２】
記録媒体１を構成するインク受容層３も、顔料を主体とする通常のインク受容層と同様に形成してある。
顔料としては、例えば、無定型シリカ、沈殿法のシリカ、ゲルタイプのシリカ、気相法シリカ、擬ベーマイト等のアルミナ水和物、シリカ／アルミナハイブリッドゾル、スメクタイト粘土、炭酸カルシウム、硫酸カルシウム、硫酸バリウム、二酸化チタン、カオリン、白土、タルク、珪酸マグネシウム、珪酸カルシウム等が挙げられる。
【００１３】
インク受容層３は、インク受容層の強度を高める観点から、バインダーを含有することが好ましい。バインダーとしては、例えば、ポリビニルアルコール、シラノール変性ポリビニルアルコール、酢酸ビニル、澱粉、カルボキシメチルセルロース等のセルロース誘導体、カゼイン、ゼラチン、スチレン−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、エチレン−酢酸ビニル共重合体等のビニル系共重合体ラテックス、アクリル酸及びメタクリル酸の重合体等のアクリル系共重合体ラテックス等が挙げられる。
【００１４】
インク受容層３には、更に助剤を含有させてもよい。助剤としては、印刷物１０の高い印字濃度及び耐水性の観点から、染料定着剤を含有することが好ましい。染料定着剤としては、例えば、カチオン性有機物、多価金属イオン及びカチオン性界面活性剤等が挙げられる。カチオン性有機物としては、例えば、１級〜３級アミン化合物、１級〜３級アミン塩、４級アンモニウム塩等の低分子化合物や、１級〜３級アミノ基、１級〜３級アミン塩基若しくは４級アンモニウム塩基を有するオリゴマー又はこれらの基を有するポリマー等が挙げられ、具体的には、ジアリルジメチルアンモニウムクロライドポリマー、エピハロヒドリン−２級アミンコポリマー、ジシアンジアミドポリアルキルアミンコポリマー、ジアリルジメチルアンモニウムクロライド−二酸化硫黄コポリマー、ジアリルジメチルアンモニウムクロライド−アクリルアミドコポリマー、ジアリルメチルアンモニウム塩ポリマー、ジアリルアミン塩酸塩−二酸化硫黄コポリマー、ジメチルメチルアミン塩酸塩コポリマー、ポリアリルアミン、ポリエチレンイミン、ポリエチレンイミン４級アンモニウム塩化合物、（メタ）アクリルアミドアルキルアンモニウム塩ポリマー、４級アンモニウム塩基を含むアイオネン等が挙げられる。多価金属イオンとしては、Ａｌ³⁺ 、Ｃａ²⁺ 、Ｍｇ²⁺ 等が挙げられる。カチオン性界面活性剤としては、塩化ベンザルコニウム等が挙げられる。
【００１５】
その他の助剤として、光安定剤、蛍光増白剤、紫外線吸収剤、耐水化剤、酸化防止剤、防かび剤、分散剤、界面活性剤、増粘剤、ｐＨ調整剤、消泡剤等が挙げられる。
【００１６】
印刷物を構成する前記染料インクとしては、インクジェット記録に一般的に使用される染料インクであればよいが、本発明の印刷物の劣化防止方法は、染料インクとして、特に水系の染料インクを用いた印刷物に対して有効である。このような水系の染料インクは、通常、染料、溶媒及び補助薬品からなる。
前記水系の染料インクに用いられる染料としては、例えば、直接染料、酸性染料、塩基性染料、反応性染料、食用色素等の水溶性染料が挙げられる。
【００１７】
前記水系の染料インクに用いられる溶媒としては、水及び水溶性の各種有機溶媒、例えば、メチルアルコール、エチルアルコール等の炭素数１〜４のアルキルアルコール類、グリセリン、エチレングリコール等の多価アルコール類等が挙げられる。
【００１８】
前記水系の染料インクに用いられる補助薬品としては、例えば、湿潤剤、分散剤、消泡剤、表面張力調整剤、防かび剤、ｐＨ調整剤、酸化防止剤、粘度調整剤等が挙げられる。
【００１９】
本発明の劣化防止方法の対象である印刷物は、前記記録媒体に、前記染料インクにより画像及び／又は文字がインクジェット記録されてなるもので、この印刷物の構成は、従来のこの種の印刷物と特に変わらない。ここで言う「インクジェット記録」の方式は、ノズルから前記染料インクの液滴を前記記録媒体に直接吐出、付着させ得るものをいう。
【００２０】
次に、本発明の劣化防止方法の対象である印刷物１０の劣化防止方法の実施形態について説明する。
【００２１】
本実施形態の劣化防止方法に用いられる処理液は、樹脂を好ましくは３０〜９８重量％、更に好ましくは４０〜８０重量％含有し、耐光性向上剤を好ましくは０．０１〜２５重量％、更に好ましくは０．１〜５重量％含有し、インク定着剤を好ましくは０．５〜２５重量％、更に好ましくは２〜１０重量％含有する該樹脂の水系分散液（エマルジョン）であり、該エマルジョンは、その最低造膜温度（ＭＦＴ）が７０℃以上、好ましくは７０〜１４０℃、更に好ましくは１００〜１２０℃である。
前記処理液中における各成分の含有量をそれぞれ前記範囲内とすることにより、画像及び／又は文字に悪影響を及ぼすことなく、一層効果的に印刷物の耐光性及び耐ガス性を向上させることができる。
尚、「最低造膜温度（ＭＦＴ）」とは、エマルジョンを被着剤に塗付したとき、粒子が融着して連続した皮膜を形成することのできる最低温度をいう〔ＪＩＳ工業用語大辞典第４版、（財）日本規格協会〕。ＭＦＴは、ＪＩＳＫ６８００に従い、測定される。
【００２２】
前記処理液中に含有される前記樹脂は、印刷物［記録媒体における耐水性基材が、温度２０℃、相対湿度９０％の環境下における酸素透過率３０ｃｃ／（ｍ² ・Ｄ・ａｔｍ）以上の耐水性紙であり、そのインク受容層に染料インクにより画像の形成された印刷物］の画像の表面に該樹脂を塗工量１５ｇ／ｍ² で塗工することにより、該印刷物の温度２０℃、相対湿度９０％の環境下における酸素透過率を１０ｃｃ／（ｍ² ・Ｄ・ａｔｍ）以下にし得る樹脂である。ここで、前記樹脂が塗工される印刷物は、本実施形態の劣化防止方法の対象となる印刷物１０である。このような樹脂を含有する前記処理液で印刷物１０を処理することにより、印刷物１０に十分な耐ガス性を付与することができる。
尚、前記樹脂の前記塗工量と前記酸素透過率との関係の規定には、前記塗工量が１５ｇ／ｍ²以下、例えば、３ｇ／ｍ²、１ｇ／ｍ²、０．１ｇ／ｍ²でも前記酸素透過率を１０ｃｃ／（ｍ² ・Ｄ・ａｔｍ）以下にし得る樹脂が含まれることは言う迄もない。
前記耐水性基材及び前記樹脂の塗工された印刷物の酸素透過率は、ＡＳＴＭ−Ｄ−１４３４に従って測定した値である。
【００２３】
前記樹脂は、水不溶性又は水難溶性の微粒子である。その平均粒径は０．０１〜１０μｍ、特に０．５〜８μｍであることが、インクの液安定性並びに該樹脂をそのガラス転移温度以上の温度で加熱した際の製膜性及び該樹脂の膜の透明性の観点から好ましい。
【００２４】
前記樹脂としては、家庭用アイロン等により、７０℃以上、好ましくは１００℃以上、更に好ましくは１２０℃以上の温度で加熱しても透明性を保持し、変色や亀裂が生じないものが良く、好ましくは、ポリオレフィン系樹脂、（メタ）アクリル酸系樹脂、スチレン−ブタジエン系樹脂、塩化ビニル系樹脂、スチレン−アクリル系樹脂、ブタジエン系樹脂、スチレン系樹脂、フェノール系樹脂、シリコン樹脂、ウレタン樹脂、エポキシ樹脂からなる群から選ばれる１種または２種以上が挙げられる。特に、透明性及び耐熱性並びに耐光性及び耐ガス性の観点から、ポリオレフィン系樹脂が好ましい。
【００２５】
前記耐光性向上剤としては、水溶性のもので、紫外光や可視光による記録画像の変退色を抑制する作用を持つものであればよく、好ましくは、紫外線吸収剤、ヒンダードアミン系光安定剤（ＨＡＬＳ）及びクエンチャー（消光剤）からなる群から選ばれる１種または２種以上が挙げられる。紫外線吸収剤としては、例えば、ベンゾフェノン系、サルシレート系、ベンゾトリアゾール系及びシアノアクリレート系、並びに酸化チタン、酸化亜鉛、酸化セレン及び酸化セリウム等の金属酸化物が挙げられる。クエンチャーとしては、例えばニッケル、コバルト等の金属錯塩系等が挙げられる。特に、染料インクの光劣化防止の観点から、紫外線吸収剤及びＨＡＬＳが好ましい。
【００２６】
前記インク定着剤としては、印刷物１０を、前記処理液で処理した際の染料インクの滲み出しを防止する作用を有するものであればよく、好ましくは、カチオン性有機物、多価金属イオン及びカチオン性界面活性剤からなる群から選ばれる１種または２種以上が挙げられる。カチオン性有機物、多価金属イオン及びカチオン性界面活性剤は、それぞれ前記染料定着剤と同様のものが使用できる。特に、染料インクの耐光性を阻害せずに、該染料インクの定着性を向上させる観点から、カチオン性有機物、とりわけエピハロヒドリン−２級アミンコポリマー及びジシアンジアミドポリアルキルアミンコポリマーが好ましい。
【００２７】
前記処理液には、前述の各成分（樹脂、耐光性向上剤及びインク定着剤）に加えて、必要に応じて添加剤を適宜配合してもよい。添加剤としては、例えば、無機顔料、分散剤、粘度調整剤、防腐剤、防かび剤等を、これらの１種又は２種以上で用いることができる。
【００２８】
前記処理液は、前述の各成分と、必要に応じて前記添加剤とを適宜配合して、前記樹脂のエマルジョンとして調整されるが、フィルム剥離工程（後述する）における印刷物１０からのフィルムの剥離性を向上させる観点から、該添加剤として、無機顔料を配合することが好ましい。無機顔料としては、インク受容層３に用いられる前記顔料と同様のものが使用できる。特に、保護層４（後述する）に補助的なインク吸収能を付与すると共に、該保護層４の透明性を向上させる観点から、シリカゲル、アルミナゾル等の白色顔料が好ましい。また、該白色顔料は、その平均粒径が０．０１〜０．１μｍであることが、該保護層４の透明性を向上させる観点から好ましい。
【００２９】
前述の如く、前記処理液に更に前記無機顔料を配合する場合、その含有量は、フィルムの剥離性と前記保護層４の透明性とのバランスの観点から、該処理液中、好ましくは１〜５０重量％、更に好ましくは５〜２０重量％である。
【００３０】
また、前記処理液には、前記樹脂の分散安定性の観点から、前記添加剤として、分散剤を配合することが好ましい。分散剤としては、従来公知のものが用いられ、例えば、ポリカルボン酸塩、スチレン−アクリル酸系樹脂、末端アルキル基変性ポリビニルアルコール等の高分子型分散剤や、ジアルキルスルコハク酸誘導体、アルキルナフタレンスルホン酸塩等の乳化重合用分散剤等が挙げられる。
【００３１】
前述の如く、前記処理液に更に前記分散剤を配合する場合、その含有量は、該処理液中、好ましくは０．００１〜１重量％、更に好ましくは０．０１〜０．１重量％である。
【００３２】
前記処理液は、該処理液による印刷物１０の処理のし易さの向上、及び処理後の印刷物の表面を美麗に仕上げる観点から、その固形分濃度が１〜４０重量％であることが好ましく、１０〜２５重量％であることが更に好ましい。また、前記処理液は、その粘度が２００ｃｐｓ以下であることが好ましく、１０〜１００ｃｐｓであることが更に好ましい。粘度を前記範囲内とするために、例えば、前記粘度調整剤としてエタノール等のアルコール類等（粘度を下げる場合）やカルボキシメチルセルロース、デンプン等（粘度を上げる場合）を添加することもできる。
【００３３】
本実施形態の印刷物の劣化防止方法における、前記印刷物１０の前記処理液による処理は、浸積工程と、予備乾燥工程と、フィルム接着工程と、フィルム剥離工程とを備え、次のようにして実施される。
【００３４】
先ず、印刷物１０は、浸積工程において、前記処理液中に浸積される。浸積時間は１０秒間程度が好ましい。浸積時間が短すぎると、該処理液が印刷物１０に十分に浸透せず、また、浸積時間が長すぎても劣化防止の効果は頭打ちとなり、滲みやインク受容層の剥がれ等の不都合が生じる。
【００３５】
前記浸積工程を経た印刷物１０は、予備乾燥工程において、前記処理液（水系分散液）のＭＦＴ未満の温度で加熱されて予備乾燥される。予備乾燥方法としては、特に家庭用ドライヤー等による温風による風乾が好ましい。本実施形態の印刷物の劣化防止方法では、ＭＦＴが前記所定温度以上の前記処理液を用いているので、前記浸積工程を経た印刷物１０を、家庭用ドライヤー等により加熱しても該樹脂を溶融・膜化させることなく、湿潤状態の印刷物１０から水分を速やかに蒸発除去することができ、次工程でフィルムをきれいに貼合・接着させることが可能となって、処理後の印刷物１０の表面に光沢感に優れた鏡面を作り出すことができる。仮に、ＭＦＴが前記所定温度未満の処理液を用いた場合には、家庭用ドライヤー等による加熱によって該処理液中の樹脂が溶融・膜化してしまい、次工程でフィルムをきれいに貼合・接着させることができず、処理後の印刷物１０の表面に鏡面を作ることができない。
【００３６】
前記予備乾燥工程における予備乾燥の程度は、予備乾燥後の印刷物１０のインク受容層３上に、前記樹脂の微粒子を含有する前記処理液のゲル状物が残留する程度とする。印刷物１０の含水率としては、好ましくは１５重量％以下、更に好ましくは８重量％以下となるようにする。
【００３７】
前記予備乾燥工程を経た印刷物１０は、フィルム接着工程において、先ず、前記ゲル状物を介して、印刷物１０の画像及び／又は文字が形成された一面（インク受容層３の表面）の全面を覆うように平滑なフィルムが貼合される。次に、フィルムが貼合された印刷物１０は、該フィルムが下になるように平滑な台等の上に載置され、予め前記処理液のＭＦＴ以上の温度に加熱された家庭用アイロン等により、上（耐水性基材２のインク受容層３と反対側の面）から加熱・加圧処理される。その際、該印刷物１０の全体が均一に加熱・加圧されるようにすることが好ましい。該加熱・加圧処理により、印刷物１０が乾燥されると共に、前記ゲル状物中に残存する水分が完全に蒸発除去され、前記樹脂の微粒子が溶融して一定の流動性を持った溶融物となる。そして、該溶融物が、インク受容層３の表面の全面に均一な厚みで配されて、前記フィルムが印刷物１０に接着される。乾燥の程度は、乾燥後の印刷物１０の含水率が、好ましくは１０重量％以下、更に好ましくは６重量％以下となるようにする。
【００３８】
前記フィルムとしては、前記フィルム接着工程における取扱い容易性、コスト及び安全性の観点から、ポリエチレンテレフタレート（ＰＥＴ）樹脂フィルム、ポリエチレン（ＰＥ）樹脂フィルム、ポリプロピレン（ＰＰ）樹脂フィルム等が好ましい。また、該フィルムの厚みは、好ましくは１０〜１００μｍ、更に好ましくは２５〜５０μｍである。
【００３９】
前記フィルム接着工程を経た印刷物１０は、フィルム剥離工程において、先ず、室温まで冷却される。その際、前記溶融物が固化して、前記フィルムとインク受容層３との間に前記樹脂の層が形成される。その後、該フィルムが剥離される。
【００４０】
以上のようにして処理された印刷物１０は、図２に示すように、画像等が形成されたインク受容層３上が、厚みが好ましくは１〜５０μｍ、更に好ましくは５〜２５μｍの保護層４に被覆される。保護層４の厚みを前記範囲内とするためには、前記処理液の固形分濃度や粘度及び処理液への浸積時間等を調整すればよく、具体的には、前記厚みの保護層４を形成するには、前記処理液を、塗工量（塗布量）３〜２５ｇ／ｍ²で以て前記厚みの保護層を形成し且つ該保護層の酸素透過率が１０ｃｃ／（ｍ² ・Ｄ・ａｔｍ）以下となるように調整するのが好ましい。更に、その際、前記樹脂の塗工量換算で２〜１５ｇ／ｍ²となり且つ前記保護層の酸素透過率が１０ｃｃ／（ｍ² ・Ｄ・ａｔｍ）以下となるように前記処理液を調整するのが好ましい。１５ｇ／ｍ²超塗工しないと酸素透過率が１０ｃｃ／（ｍ² ・Ｄ・ａｔｍ）以下にならない樹脂では、処理後の印刷物の表面性を悪化させてしまうため好ましくない。このような保護層４をインク受容層３上に具備することにより、印刷物１０に十分な耐光性及び耐ガス性を付与することができる。
また、保護層４は、前述の如く、インク受容層３上に付着した前記樹脂の微粒子にフィルムを被着させた後、該樹脂の微粒子を溶融・膜化させることにより形成されるので、その表面は、該フィルムの鏡面を拾って光沢感が向上した美しいものとなる。
【００４１】
本実施形態の劣化防止方法の対象となる印刷物１０は、耐水性基材上にインク受容層を設けてなる記録媒体に、染料インクにより画像及び／又は文字を形成した印刷物であれがよいが、特に好ましい形態を挙げると、次の通りである。
前記耐水性基材２としては、ＲＣペーパー（銀塩写真用基材）が好ましく、その坪量は、好ましくは１５０〜３００ｇ／ｍ² 、更に好ましくは２００〜２５０ｇ／ｍ² である。
【００４２】
前記インク受容層３としては、前記顔料として気相法シリカを含有するものが好ましく、その平均粒子径は０．０１〜１μｍ、特に０．１〜０．５μｍであることが、インク受容層の平滑性及び解像性等の画質の向上の点で好ましく、また、そのＢＥＴによる比表面積は１５０〜３５０ｍ² ／ｇ、特に２５０〜３００ｍ² ／ｇであることが、インクの吸収性の点で好ましい。
【００４３】
前記インク受容層３は、固形分換算で、前記顔料として気相法シリカを３０〜８０重量％、特に５０〜７０重量％、前記バインダーとしてポリビニルアルコールを２０〜６０重量％、特に３０〜５０重量％、前記助剤である染料定着剤として２級アミンエピハロヒドリンのポリマーを５〜３０重量％、特に１０〜２０重量％含有することが、耐水性及び耐湿性の点で好ましい。
また、前記インク受容層３の耐水性基材２への塗工量は、固形分換算で５〜４０ｇ／ｍ² が好ましく、１０〜３０ｇ／ｍ² であることが更に好ましい。インク受容層３自体の厚みとしては、好ましくは５〜８０μｍ、更に好ましくは２０〜６０μｍである。
【００４４】
本実施形態の劣化防止方法の対象となる印刷物１０は、インクジェットプリンタにより画像及び／又は文字が形成されることが好ましい。
【００４５】
本発明の印刷物の劣化防止方法は、前記実施形態に制限されず、種々の変更が可能である。例えば、印刷物１０を、前記処理液で処理する方法として、前記実施形態では、印刷物１０を前記処理液に浸積したが、印刷物１０に前記処理液をスプレー等を用いて噴霧してもよい。
【００４６】
また、前記フィルム接着工程では、印刷物１０に平滑なフィルムを貼合したが、特定の模様が付されたフィルムを貼合してもよい。このようなフィルムを用いることにより、処理後の印刷物１０の表面に、規則的あるいは不規則な模様を付すことができ、例えば、写真のラスター面や絹面等を作ることができる。
【００４７】
また、保護層４は、インク受容層３上に設ければよく、耐水性基材２の片面に設けてもよく、両面に設けてもよい。
尚、保護層４を印刷物１０の片面に設けた場合には、印刷物１０のカールを防止するため、耐水性基材２のインク受容層３と反対側の面に予めバックコート層を設けてもよい。
【００４８】
また、インク受容層３は、耐水性基材２の片面のみならず、両面に設けてもよい。また、画質向上の観点から、インク受容層３に公知のカレンダー装置を用いて平滑化処理を施してもよい。
また、前記実施形態におけるインク受容層３に代えて、例えば、特開平１１−５８９４２号公報に記載されているように、有機カチオン性ポリマーが結合した無機微粒子を含有させた空隙を設けた層や、特開平１１−１１５３０８号公報に記載されているように、無機微粒子と水溶性樹脂と特定の架橋剤とを用いて恒率乾燥速度を示す間に該水溶性樹脂を架橋させて、硬化させることにより得られる層等を用いることもできる。その他、特開平１０−８１０６４号公報、同１０−１００３９７号公報、同１０−１１９４２０号公報、同１０−１１９４２３号公報、同１０−１１９４２４号公報、同１０−１７５３６５号公報、同１０−１９３７７６号公報、同１０−２０３００６号公報、同１０−２１７６０１号公報、同１１−２０３００号公報、同１１−２０３０６号公報、特開平７−２７６７８９号公報、特開平８−１７４９９２号公報等に記載のインク受容のための層に変更することもできる。
【００４９】
また、記録媒体１に画像等を形成する方法として、前記実施形態ではインクジェット記録方式を用いたが、染料インクを用いて画像等を形成できる方法であればよく、例えば、昇華型熱転写方式、熱溶融型熱転写方式等を用いて画像等を形成してもよい。
【００５０】
本発明の印刷物の劣化防止方法は、その対象である印刷物を、特定の処理液で処理することにより、該処理液の保護層を印刷物の表面に形成し、該印刷物の耐光性及び耐ガス性を向上させるものである。従って、本発明の方法により印刷物の表面に形成される保護層の形態は、特定の処理液の乾燥によって形成される乾燥物が、印刷物の画像及び／又は文字を外気と遮断するように被覆した形態であればよい。
【００５１】
【実施例】
以下に、本発明の印刷物の劣化防止方法の実施例を示す。しかしながら、本発明は、かかる実施例に制限されるものではないことはいうまでもない。尚、以下の例中、「部」及び「％」は、特に明示しない限りそれぞれ重量部及び重量％を示す。
【００５２】
〔実施例１〕
下記の印刷物Ａ及びＢの製法それぞれで得られた印刷物Ａ及びＢを、下記製造例１で得られた処理液中にそれぞれ５秒間浸積した後、それらを引き上げて家庭用ドライヤーにより８０℃（該処理液のＭＦＴ未満の温度）で加熱して、予備乾燥した。その後、各印刷物の画像及び／又は文字が形成された一面（インク受容層の表面）の全面を覆うように、厚さ２５μｍのＰＥＴフィルム（コロナ処理無し、ユニチカ製）を貼合した。そして、該フィルムが下になるように、各印刷物を平滑な台の上に載置し、予め１４０℃（前記処理液のＭＦＴ以上の温度）に加熱された家庭用アイロンにより、各印刷物の全体をそれぞれ均一に加熱・加圧して、該フィルムを接着すると共に、各印刷物を乾燥した。各印刷物を室温まで冷却した後、該フィルムを剥離して、処理印刷物Ａ１及びＢ１（何れも含水率７重量％）を得た。何れも塗布量は５〜１０ｇ／ｍ²であった。
【００５３】
〔印刷物Ａの製法〕
耐水性基材上にインク受容層を設けてなる記録媒体として、市販のインクジェット用記録媒体（商品名「ＰＭ写真用紙」、ＥＰＳＯＮ製）を用い、これに、染料インク（Ｃ，Ｍ，Ｙ，Ｂｋ４色の１００％パッチ）を用いてインクジェットプリンター（商品名「ＰＭ８００Ｃ」、セイコーエプソン社製）によりカラーパッチを印刷し、印刷物Ａを得た。
【００５４】
〔印刷物Ｂの製法〕
前記印刷物の製法Ａで用いたものと同様の記録媒体に、前記印刷物の製法Ａで用いたものと同様の染料インクを用いて前記ＰＭ８００Ｃにより、高精細カラーデジタル標準画像［（ＩＳＯ／ＪＩＳ−ＳＣＩＤ）、画像名称「ポートレート」（サンプル番号１、画像の評価認識番号Ｎ１）］を印刷して、印刷物Ｂを得た。
【００５５】
〔比較例１〜４〕
実施例１における下記処理液に代えて、下記比較製造例１〜４でそれぞれ得られた処理液を用いた以外は実施例１と同様にして、それぞれ比較処理印刷物Ａ’１〜Ａ’４及びＢ’１〜Ｂ’４を得た。
【００５６】
〔製造例１〕
水２５０部に、ポリオレフィン樹脂エマルジョン（固形分濃度４０％、商品名「ケミパール」、三井化学製）９６．５部、水溶性紫外線吸収剤（商品名「ニードラル」、多木化学製）３部及びインク定着剤（商品名「スミレーズレジン１００１」、住友化学製）０．５部を添加し、混合して、固形分濃度２８．５％、粘度５０ｃｐｓの処理液を得た。
【００５７】
〔比較製造例１〕
製造例１における水溶性紫外線吸収剤の代わりに水を用いた以外は製造例１と同様にして、固形分濃度２５．５％、粘度４５ｃｐｓの処理液を得た。
【００５８】
〔比較製造例２〕
製造例１における水溶性紫外線吸収剤及びインク定着剤の代わりに水を用いた以外は製造例１と同様にして、固形分濃度２５％、粘度４４ｃｐｓの処理液を得た。
【００５９】
〔比較製造例３〕
製造例１におけるポリオレフィン樹脂エマルジョンの代わりにアクリル樹脂エマルジョン（固形分濃度４０％、商品名「ボンロン」、三井化学製）を用いた以外は製造例１と同様にして、固形分濃度２８．５％、粘度４８ｃｐｓの処理液を得た。
【００６０】
〔比較製造例４〕
製造例１におけるポリオレフィン樹脂エマルジョンの代わりにでんぷん（商品名「ＭＳ３８００」、日本食品加工製）１０部及び水１００部を用いた以外は製造例１と同様にして、固形分濃度１３．５％、粘度９５ｃｐｓの処理液を得た。
【００６１】
〔処理性、耐ガス性、画質変化性、耐水性、耐湿性及び耐光性の評価〕
実施例１で得られた処理印刷物Ａ１、及び比較例１〜４でそれぞれ得られた比較処理印刷物Ａ’１〜Ａ’４それぞれについて、下記の〔処理性の評価基準〕、〔耐ガス性の評価基準〕及び〔画質変化性の評価基準〕により評価した。それらの結果を下記表１に示す。尚、〔耐水性の評価〕及び〔耐湿性の評価〕については、処理印刷物Ａ１並びに比較処理印刷物Ａ’１、Ａ’３及びＡ’４についてのみ行い、下記の〔耐水性の評価基準〕及び〔耐湿性の評価基準〕により評価した。
また、実施例１で得られた処理印刷物Ｂ１、及び比較例１〜４でそれぞれ得られた比較処理印刷物Ｂ’１〜Ｂ’４それぞれについて、下記の〔耐光性の評価基準〕により評価した。その結果を下記表１に示す。
【００６２】
〔処理性の評価基準〕
処理印刷物Ａ１及び比較処理印刷物Ａ’１〜Ａ’４それぞれの「表面状態」及び「染料の滲み出し程度」を目視で観察し、それぞれ下記評価基準により評価した。尚、「表面状態」は、フィルム剥離直後の表面状態についてのものであり、また、「染料の滲み出し程度」は、フィルム貼合前（予備乾燥後）についてのものである。
〔表面状態の評価基準〕
○：処理前と比較して光沢感が向上している。
△：処理前と比較して多少凹凸がある。実用限界。
×：処理前と比較して曇り、亀裂、凹凸が生じており、実用不可。
××：フィルムを剥離する際に、基材の破れやインク受容層の剥離が起こる。
〔染料の滲み出し程度の評価基準〕
○：滲みは全く観察されない。
×：Ｃ，Ｍ，Ｙ，Ｂｋのうち少なくとも１色の滲みが観察できる。
【００６３】
〔耐ガス性の評価基準〕
処理印刷物Ａ１及び比較処理印刷物Ａ’１〜Ａ’４それぞれを、ガス導入口及び排出口の付いたガラス容器に入れ、ガス発生器にて発生させた混合ガス（オゾン１ｐｐｍ、ＮＯ₂５ｐｐｍ、ＳＯ₂１ｐｐｍ）を３０分間連続して導入してガス処理を行った。ガス処理後の処理印刷物及び各比較処理印刷物について、色差計を用い、ガス処理前の処理印刷物及び各比較処理印刷物に対する色差（Ｃ，Ｍ，Ｙ３色についての平均値）をそれぞれ求め、下記評価基準により評価した。
〔評価基準〕
○：色差が５未満。耐ガス性良好。
△：色差が５以上１５未満。実用限界。
×：色差が１５以上。実用に堪えない。
【００６４】
〔画質変化性の評価基準〕
印刷物Ａ（処理前）並びに処理印刷物Ａ１及び比較処理印刷物Ａ’１〜Ａ’４（処理後）それぞれについて、反射濃度測定器（「ＳＰＭ５０−１」、グレタグマクベス社製）を用い反射濃度を測定して、ＯＤ変化率（Ｃ，Ｍ，Ｙ３色についての平均値）を求め、下記評価基準により評価した。
〔評価基準〕
○：ＯＤ変化率が５％以下。
△：ＯＤ変化率が１０％未満。
×：ＯＤ変化率が１０％以上。
【００６５】
〔耐水性の評価基準〕
処理印刷物Ａ１並びに比較処理印刷物Ａ’１、Ａ’３及びＡ’４を、温度２５℃、相対湿度５０％の環境下に２４時間放置した後、０．３ｃｃの水滴を、それぞれのＣ，Ｍ，Ｙ，Ｂｋのパッチ１００％部分に滴下し、更に、温度２５℃、相対湿度５０％の環境下に２４時間放置した。その後、処理印刷物Ａ１並びに比較処理印刷物Ａ’１、Ａ’３及びＡ’４それぞれについての前記「染料の滲み出し程度」を目視で観察し、下記評価基準により評価した。
〔評価基準〕
○：滲みは全く観察されない。耐水性良好。
△：Ｃ，Ｍ，Ｙ，Ｂｋのうちの２色の滲みが観察できる。実用限界。
×：Ｃ，Ｍ，Ｙ，Ｂｋのうちの３色以上の滲みが観察できる。実用に堪えない。
【００６６】
〔耐湿性の評価基準〕
処理印刷物Ａ１並びに比較処理印刷物Ａ’１、Ａ’３及びＡ’４を、温度２５℃、相対湿度５０％の環境下に２４時間放置して乾燥処理を行った後、温度４０℃、相対湿度８０％の環境下に２４時間放置して湿潤処理を行った。湿潤処理後の処理印刷物Ａ１並びに比較処理印刷物Ａ’１、Ａ’３及びＡ’４それぞれの画像背景部分について、色差計を用い、湿潤処理前（乾燥処理後）の処理印刷物Ａ１並びに比較処理印刷物Ａ’１、Ａ’３及びＡ’４それぞれに対する色差（Ｃ，Ｍ，Ｙ３色についての平均値）を求め、下記評価基準により評価した。
〔評価基準〕
○：色差が５未満。耐湿性良好。
△：色差が５以上１０未満。実用限界。
×：色差が１０以上。実用に堪えない。
【００６７】
〔耐光性の評価基準〕
処理印刷物Ｂ１及び比較処理印刷物Ｂ’１〜Ｂ’４それぞれを、キセノンウェザオメーターＣｉ３５Ａ（ＡＴＬＡＳ社製）を用いて、３４０ｎｍの放射エネルギー０．２５Ｗ／ｍ² 、ブラックパネル温度６３℃、相対湿度５０％ＲＨの環境下で、４５ｋＪ／ｍ² の光暴露処理を行った。光暴露処理後の処理印刷物Ｂ１及び比較処理印刷物Ｂ’１〜Ｂ’４それぞれの画像背景部分について、色差計を用い、光暴露前処理前の処理印刷物Ｂ１及び比較処理印刷物Ｂ’１〜Ｂ’４それぞれに対する色差（Ｃ，Ｍ，Ｙ３色及び画像背景部分についての平均値）を求め、下記評価基準により評価した。
〔評価基準〕
○：色差が５未満。耐光性良好。
△：色差が５以上１０未満。実用限界。
×：色差が１０以上。実用に堪えない。
【００６８】
〔酸素透過率の測定〕
処理印刷物Ａ１及び比較処理印刷物Ａ’１〜Ａ’４それぞれの温度２０℃、相対湿度９０％の環境下における酸素透過率を、前記ＡＳＴＭ−Ｄ−１４３４に従って測定した。その結果を下記表１に示す。
【００６９】
〔ＭＦＴの測定〕
製造例１及び比較製造例１〜４でそれぞれ得られた処理液のＭＦＴを、前記ＪＩＳＫ６８００に従って測定した。その結果を下記表１に示す。
【００７０】
【表１】

【００７１】
表１に示す結果から明らかなように、実施例１の印刷物の劣化防止方法に従って、処理液（製造例１）で処理した印刷物は、処理性、耐ガス性、画質変化性、耐水性、耐湿性、耐光性及び酸素透過率の全てにおいて優れるものであることが分かる。これに対し、比較例１〜４の印刷物の劣化防止方法に従って、処理液（比較製造例１〜４）で処理した印刷物は、何れも処理性、耐ガス性、画質変化性、耐水性、耐湿性及び酸素透過率の何れかが十分なレベルに達していないことが分かる。尚、実施例１の印刷物の劣化防止方法においては、印刷物を処理液中に浸積させることにより、該処理液を該印刷物に含浸させたが、「処理液中への浸積」に代えて、「スプレーによる処理液の噴霧」により該処理液を該印刷物に含浸させても、同様の結果が得られた。
【００７２】
また、実施例１と比較例１及び２との対比から、画質変化を伴わずに、印刷物の耐ガス性及び耐光性を向上させるためには、本発明の処理液の必須成分である樹脂、耐光性向上剤及びインク定着剤が必要であることが分かる。
また、実施例１と比較例３との対比から、処理後の印刷物の光沢感を向上させるためには、処理液のＭＦＴが一定温度以上である必要があることが分かる。比較例３では、ＭＦＴが低い処理液で印刷物を処理したため、家庭用ドライヤーによる予備乾燥で該処理液中に分散された樹脂が溶融・膜化してしまい、次工程でフィルム貼合・接着をきれいに行うことができなかった。
また、実施例１と比較例４との対比から、処理液としては、酸素透過率が一定値以下である樹脂を分散状態で含有させたものを用いる必要があることが分かる。
【００７３】
【発明の効果】
本発明の印刷物の劣化防止方法によれば、画質をほとんど変化させることなく、印刷物の劣化防止、特に印刷物の耐光性及び耐ガス性を向上させて、紫外光や可視光、酸化性ガス等による該印刷物の変退色を防止することができ、また、特別な装置を用いることなく、家庭用ドライヤーや家庭用アイロン等で行うことができるので、一般の家庭でも容易に印刷物の劣化防止処理を行うことができる。更に、劣化防止処理後の印刷物は、その印刷面が鏡面仕上げされ、光沢感が向上した美しいものになる。
【図面の簡単な説明】
【図１】本発明の印刷物の劣化防止方法に用いられる印刷物の断面を拡大して示す拡大断面図である。
【図２】本発明の印刷物の劣化防止方法により処理された処理後の印刷物の断面を拡大して示す拡大断面図である。
【符号の説明】
１記録媒体
２耐水性基材
３インク受容層
４保護層
１０印刷物[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for preventing deterioration of printed matter, in particular, printed matter recorded by inkjet, and a treatment liquid used for the method for preventing deterioration.
[0002]
[Prior art and problems to be solved by the invention]
Due to recent advances in ink-jet recording technology, images output to a recording medium by ink-jet recording have been improved in quality, and high-quality images comparable to silver salt photographs can be output. However, dye ink, which is an ink for ink jet recording used for outputting a high-quality image, has a defect that it is likely to discolor with time due to ultraviolet light, visible light, moisture, nitrogen oxide gas, ozone gas, or the like. For this reason, printed matter recorded by inkjet using dye ink is inferior in light resistance, water resistance and gas resistance, and recorded images such as discoloration are deteriorated under a normal environment such as being stuck on an indoor wall. Etc., still not as good as silver salt photography in terms of storage stability (preventing deterioration).
[0003]
Also, as an ink jet recording medium, a so-called absorption type having an ink receiving layer containing a microporous material such as amorphous silica is the mainstream, and the porous pigment is used for the purpose of pursuing higher image quality. As a result, a further miniaturized one tends to be used. However, when the porous pigment is further miniaturized, the specific surface area is proportionally increased, so that the contact between the porous pigment in the ink-receiving layer and the outside air is improved, and as a result, the storability of the printed matter, particularly the gas resistance, is increased. May decrease.
[0004]
Further, although the ink-jet recording medium itself has been sufficiently satisfactory in water resistance, its light resistance and gas resistance are still problems.
As a technique for improving light resistance and gas resistance of an ink jet recording medium, for example, an improvement in light resistance and gas resistance of an ink receiving layer itself constituting the ink jet recording medium (Japanese Patent Laid-Open No. 9-254526). JP, 8-164664, JP-A-5-221115, and JP-A-7-246769, etc.), a film having light resistance and gas resistance, a resin layer, etc. laminated on the image surface (See JP-A-8-252985, JP-A-8-252883, JP-A-5-318943, JP-A-8-174899, JP-A-8-207429, JP-A-9-174959, etc. However, none of them can provide sufficient light resistance and gas resistance to an inkjet recording medium.
[0005]
As described above, dye ink is composed of ultraviolet light, visible light, moisture, nitrogen oxide gas, H ₂ The ink recording medium has the disadvantage that it is likely to be discolored and faded with time due to S gas, sulfur oxide gas, ozone gas, and the like, and the ink jet recording medium has the disadvantage of low light resistance and gas resistance. For this reason, the printed matter recorded with the dye ink on the inkjet recording medium has a problem particularly in light resistance and gas resistance.
[0006]
Accordingly, the object of the present invention is to prevent deterioration of the printed matter, particularly improve the light resistance and gas resistance of the printed matter, by simply performing a simple treatment on the printed matter, and the printed matter by ultraviolet light, visible light, oxidizing gas, etc. It is an object of the present invention to provide a method for preventing deterioration of printed matter that can prevent the color fading.
[0007]
The present inventors disperse a printed material in which an image and / or characters are formed with a dye ink on a recording medium having an ink-receiving layer on a water-resistant substrate, a specific treatment liquid, specifically a specific resin in a dispersed state. It was found that the above-mentioned purpose can be achieved by treating with the treatment liquid contained in the above.
[0008]
[Means for Solving the Problems]
The present invention has been made on the basis of the above findings, and is a printed material in which an image and / or characters are formed with a dye ink on a recording medium in which an ink receiving layer is provided on a water-resistant substrate. The treatment liquid is an aqueous dispersion of the resin containing a resin, a light fastness improver, and an ink fixing agent. , That The minimum film forming temperature is 70 ° C. or higher, and the resin is a printed material [oxygen permeability of 30 cc / (m in a water-resistant base material in a recording medium at a temperature of 20 ° C. and a relative humidity of 90%]. ² D · atm) or more water-resistant paper, and the resin coating amount is 15 g / m on the surface of the image of the printed matter in which the ink receiving layer is formed with dye ink. ² Coating, the oxygen transmission rate of the printed matter in an environment of a temperature of 20 ° C. and a relative humidity of 90% is 10 cc / (m ² ・ D ・ atm) Resin R , The treatment with the treatment liquid is performed by immersing the printed matter before treatment in the treatment liquid, and heating the printed matter that has undergone the immersion step at a temperature lower than the minimum film-forming temperature of the aqueous dispersion. A pre-drying step for pre-drying, a film is adhered to one surface on which images and / or characters of the printed matter that have undergone the pre-drying step are formed, and the printed matter is at a temperature equal to or higher than the minimum film-forming temperature of the aqueous dispersion. A film adhering process for heating and drying the film, and a film exfoliating process for exfoliating the film from the printed matter The present invention provides a method for preventing deterioration of printed matter.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a preferred embodiment of the method for preventing deterioration of printed matter of the present invention will be described with reference to FIGS.
First, the printed matter 10 that is the subject of the degradation prevention method of the present embodiment will be described.
As shown in FIG. 1, the printed material 10 is formed by forming an image and / or characters (not shown) with dye ink on a recording medium 1 in which an ink receiving layer 3 is provided on a water-resistant substrate 2. It is. The recording medium 1 constituting the printed matter 10 and the dye ink are the same as those in this kind of printed matter.
[0010]
As the water-resistant substrate 2 constituting the recording medium 1, a water-resistant substrate that is water-resistant and difficult to expand and contract by the liquid treatment process is used. For example, sized paper, polyethylene, polypropylene, polyester, etc. are used as paper. Resin-coated paper coated on the surface, photographic base materials such as baryta paper and RC paper, thermoplastic resin films such as polyethylene terephthalate, polyethylene and polypropylene, synthetic paper, and sheet-like materials formed of synthetic fibers.
[0011]
From the viewpoint of improving gas resistance, the oxygen permeability of the water-resistant substrate 2 in an environment of a temperature of 20 ° C. and a relative humidity of 90% is preferably 50 cc / (m ² · D · atm) or less, more preferably 30 cc / (m ² D · atm) or less. A method for measuring oxygen permeability will be described later.
[0012]
The ink receiving layer 3 constituting the recording medium 1 is also formed in the same manner as a normal ink receiving layer mainly composed of pigment.
Examples of the pigment include amorphous silica, precipitated silica, gel type silica, vapor phase silica, pseudoboehmite and other alumina hydrates, silica / alumina hybrid sol, smectite clay, calcium carbonate, calcium sulfate, sulfuric acid. Barium, titanium dioxide, kaolin, white clay, talc, magnesium silicate, calcium silicate and the like can be mentioned.
[0013]
The ink receiving layer 3 preferably contains a binder from the viewpoint of increasing the strength of the ink receiving layer. Examples of the binder include polyvinyl alcohol, silanol-modified polyvinyl alcohol, cellulose derivatives such as vinyl acetate, starch, carboxymethyl cellulose, conjugated diene copolymer latex such as casein, gelatin, and styrene-butadiene copolymer, ethylene-vinyl acetate. Examples thereof include vinyl copolymer latexes such as copolymers, and acrylic copolymer latexes such as polymers of acrylic acid and methacrylic acid.
[0014]
The ink receiving layer 3 may further contain an auxiliary agent. The auxiliary agent preferably contains a dye fixing agent from the viewpoint of high print density and water resistance of the printed product 10. Examples of the dye fixing agent include cationic organic substances, polyvalent metal ions, and cationic surfactants. Examples of the cationic organic substance include low molecular compounds such as primary to tertiary amine compounds, primary to tertiary amine salts, and quaternary ammonium salts, primary to tertiary amino groups, and primary to tertiary amine bases. Or an oligomer having a quaternary ammonium base or a polymer having these groups, specifically, diallyldimethylammonium chloride polymer, epihalohydrin-secondary amine copolymer, dicyandiamide polyalkylamine copolymer, diallyldimethylammonium chloride-dioxide Sulfur copolymer, diallyldimethylammonium chloride-acrylamide copolymer, diallylmethylammonium salt polymer, diallylamine hydrochloride-sulfur dioxide copolymer, dimethylmethylamine hydrochloride copolymer, polyallylamine, polyethylene N'imin, polyethyleneimine quaternary ammonium salt compounds, (meth) acrylamide alkyl ammonium salt polymers, ionene like including a quaternary ammonium base. As the polyvalent metal ion, Al ³⁺ , Ca ²⁺ , Mg ²⁺ Etc. Examples of the cationic surfactant include benzalkonium chloride.
[0015]
Other auxiliary agents include light stabilizers, fluorescent brighteners, UV absorbers, water resistance agents, antioxidants, fungicides, dispersants, surfactants, thickeners, pH adjusters, antifoaming agents, etc. Is mentioned.
[0016]
The dye ink constituting the printed material may be a dye ink generally used for ink jet recording. However, the method for preventing deterioration of the printed material according to the present invention is a printed material using a water-based dye ink as the dye ink. It is effective against. Such a water-based dye ink is usually composed of a dye, a solvent and auxiliary chemicals.
Examples of the dye used in the water-based dye ink include water-soluble dyes such as direct dyes, acid dyes, basic dyes, reactive dyes, and food dyes.
[0017]
Examples of the solvent used in the aqueous dye ink include water and various water-soluble organic solvents, for example, alkyl alcohols having 1 to 4 carbon atoms such as methyl alcohol and ethyl alcohol, and polyhydric alcohols such as glycerin and ethylene glycol. Etc.
[0018]
Examples of auxiliary chemicals used in the aqueous dye ink include a wetting agent, a dispersing agent, an antifoaming agent, a surface tension adjusting agent, an antifungal agent, a pH adjusting agent, an antioxidant, and a viscosity adjusting agent.
[0019]
The printed matter that is the object of the deterioration preventing method of the present invention is one in which images and / or characters are inkjet-recorded on the recording medium with the dye ink. does not change. The “inkjet recording” method mentioned here refers to a method in which droplets of the dye ink can be directly ejected and adhered to the recording medium from nozzles.
[0020]
Next, an embodiment of a method for preventing deterioration of the printed matter 10 that is a target of the method for preventing deterioration of the present invention will be described.
[0021]
The treatment liquid used in the deterioration preventing method of the present embodiment preferably contains 30 to 98% by weight of resin, more preferably 40 to 80% by weight, and preferably 0.01 to 25% by weight of light resistance improver, An aqueous dispersion (emulsion) of the resin containing 0.1 to 5% by weight, preferably 0.5 to 25% by weight, and more preferably 2 to 10% by weight of an ink fixing agent, The emulsion has a minimum film-forming temperature (MFT) of 70 ° C. or higher, preferably 70 to 140 ° C., more preferably 100 to 120 ° C.
By setting the content of each component in the treatment liquid within the above range, the light resistance and gas resistance of the printed matter can be more effectively improved without adversely affecting images and / or characters. .
The “minimum film-forming temperature (MFT)” refers to the lowest temperature at which particles can be fused to form a continuous film when an emulsion is applied to an adherent [JIS Industrial Terms Dictionary]. 4th edition, Japan Standards Association]. MFT is measured according to JIS K 6800.
[0022]
The resin contained in the treatment liquid is a printed matter [oxygen permeability of 30 cc / (m in an environment where the water-resistant substrate in the recording medium is at a temperature of 20 ° C. and a relative humidity of 90%. ² D · atm) or more water-resistant paper, and the resin coating amount is 15 g / m on the surface of the image of the printed matter in which the ink receiving layer is formed with dye ink. ² Coating, the oxygen transmission rate of the printed matter in an environment of a temperature of 20 ° C. and a relative humidity of 90% is 10 cc / (m ² (D · atm) A resin that can be reduced to the following. Here, the printed material to which the resin is applied is the printed material 10 that is a target of the deterioration prevention method of the present embodiment. By treating the printed material 10 with the treatment liquid containing such a resin, it is possible to impart sufficient gas resistance to the printed material 10.
In addition, in the regulation of the relationship between the coating amount of the resin and the oxygen transmission rate, the coating amount is 15 g / m. ² Hereinafter, for example, 3 g / m ² 1g / m ² 0.1 g / m ² However, the oxygen permeability is 10 cc / (m ² -D · atm) Needless to say, a resin that can be made below is included.
The oxygen permeability of the water-resistant substrate and the printed material coated with the resin is a value measured according to ASTM-D-1434.
[0023]
The resin is water-insoluble or hardly water-soluble fine particles. The average particle size is 0.01 to 10 μm, particularly 0.5 to 8 μm. The liquid stability of the ink, the film forming property when the resin is heated at a temperature equal to or higher than the glass transition temperature, and the resin It is preferable from the viewpoint of transparency of the film.
[0024]
As the resin, a resin that maintains transparency even when heated at a temperature of 70 ° C. or higher, preferably 100 ° C. or higher, more preferably 120 ° C. or higher with a household iron or the like, and does not cause discoloration or cracking. Preferably, polyolefin resin, (meth) acrylic acid resin, styrene-butadiene resin, vinyl chloride resin, styrene-acrylic resin, butadiene resin, styrene resin, phenolic resin, silicon resin, urethane resin, 1 type, or 2 or more types chosen from the group which consists of an epoxy resin is mentioned. In particular, polyolefin resins are preferred from the viewpoints of transparency, heat resistance, light resistance, and gas resistance.
[0025]
The light fastness improver may be water-soluble and has an action of suppressing discoloration of a recorded image due to ultraviolet light or visible light. Preferably, an ultraviolet absorber, a hindered amine light stabilizer ( 1 type or 2 types or more chosen from the group which consists of HALS) and a quencher (quenching agent) is mentioned. Examples of the ultraviolet absorber include benzophenone-based, salicylate-based, benzotriazole-based, and cyanoacrylate-based, and metal oxides such as titanium oxide, zinc oxide, selenium oxide, and cerium oxide. Examples of the quencher include metal complex salts such as nickel and cobalt. In particular, an ultraviolet absorber and HALS are preferable from the viewpoint of preventing the light deterioration of the dye ink.
[0026]
The ink fixing agent is not particularly limited as long as it has a function of preventing the dye ink from exuding when the printed matter 10 is treated with the treatment liquid, and is preferably a cationic organic substance, a polyvalent metal ion and a cationic substance. 1 type (s) or 2 or more types chosen from the group which consists of surfactant are mentioned. As the cationic organic substance, the polyvalent metal ion, and the cationic surfactant, those similar to the dye fixing agent can be used. In particular, from the viewpoint of improving the fixing property of the dye ink without impairing the light resistance of the dye ink, a cationic organic substance, particularly an epihalohydrin-secondary amine copolymer and a dicyandiamide polyalkylamine copolymer are preferable.
[0027]
In addition to the above-described components (resin, light resistance improver, and ink fixing agent), additives may be appropriately added to the treatment liquid as necessary. As additives, for example, inorganic pigments, dispersants, viscosity modifiers, preservatives, fungicides and the like can be used as one or more of these.
[0028]
The treatment liquid is prepared as an emulsion of the resin by appropriately blending the above-described components and, if necessary, the additive, and peeling of the film from the printed material 10 in a film peeling step (described later). From the viewpoint of improving the properties, it is preferable to blend an inorganic pigment as the additive. As the inorganic pigment, the same pigments as those used in the ink receiving layer 3 can be used. In particular, white pigments such as silica gel and alumina sol are preferred from the viewpoints of providing auxiliary ink absorbing ability to the protective layer 4 (described later) and improving the transparency of the protective layer 4. The white pigment preferably has an average particle size of 0.01 to 0.1 μm from the viewpoint of improving the transparency of the protective layer 4.
[0029]
As described above, when the inorganic pigment is further added to the treatment liquid, the content thereof is preferably 1 to 4 in the treatment liquid from the viewpoint of the balance between the peelability of the film and the transparency of the protective layer 4. 50% by weight, more preferably 5 to 20% by weight.
[0030]
Moreover, it is preferable to mix | blend a dispersing agent with the said process liquid as said additive from a viewpoint of the dispersion stability of the said resin. As the dispersant, conventionally known ones are used. For example, polymer dispersants such as polycarboxylates, styrene-acrylic acid resins, terminal alkyl group-modified polyvinyl alcohol, dialkyl succinic acid derivatives, alkyl naphthalene, etc. Examples include emulsion polymerization dispersants such as sulfonates.
[0031]
As described above, when the dispersant is further added to the treatment liquid, the content thereof is preferably 0.001 to 1% by weight, more preferably 0.01 to 0.1% by weight in the treatment liquid. is there.
[0032]
The treatment liquid preferably has a solid content concentration of 1 to 40% by weight from the viewpoint of improving the ease of treatment of the printed matter 10 with the treatment liquid and beautifully finishing the surface of the printed matter after the treatment. More preferably, it is 10 to 25% by weight. Further, the treatment liquid preferably has a viscosity of 200 cps or less, and more preferably 10 to 100 cps. In order to make the viscosity within the above range, for example, alcohols such as ethanol (when the viscosity is lowered), carboxymethylcellulose, starch and the like (when the viscosity is raised) can be added as the viscosity modifier.
[0033]
In the printed matter deterioration prevention method of the present embodiment, the treatment of the printed matter 10 with the treatment liquid includes an immersion step, a preliminary drying step, a film adhesion step, and a film peeling step, and is performed as follows. Is done.
[0034]
First, the printed material 10 is immersed in the treatment liquid in the immersion process. The immersion time is preferably about 10 seconds. If the immersion time is too short, the treatment liquid does not sufficiently penetrate into the printed material 10, and if the immersion time is too long, the effect of preventing deterioration will reach its peak, and there are inconveniences such as bleeding and peeling of the ink receiving layer. Arise.
[0035]
In the preliminary drying step, the printed material 10 that has undergone the immersion step is heated at a temperature lower than the MFT of the treatment liquid (aqueous dispersion) and preliminary dried. As the preliminary drying method, air drying with warm air using a household dryer or the like is particularly preferable. In the printed matter deterioration prevention method of the present embodiment, since the MFT uses the treatment liquid having the predetermined temperature or more, the resin melts even when the printed matter 10 that has undergone the immersion process is heated by a domestic drier or the like.・ Moisture can be quickly evaporated and removed from the printed material 10 in a wet state without forming a film, and the film can be bonded and adhered neatly in the next step. A mirror surface with excellent gloss can be created. If a treatment liquid having an MFT of less than the predetermined temperature is used, the resin in the treatment liquid is melted and formed into a film by heating with a household dryer or the like, and the film is pasted and adhered cleanly in the next step. And a mirror surface cannot be formed on the surface of the printed matter 10 after the processing.
[0036]
The degree of preliminary drying in the preliminary drying step is such that the gel-like substance of the treatment liquid containing fine particles of the resin remains on the ink receiving layer 3 of the printed matter 10 after the preliminary drying. The water content of the printed material 10 is preferably 15% by weight or less, more preferably 8% by weight or less.
[0037]
In the film adhering step, the printed material 10 that has undergone the preliminary drying step first covers the entire surface (the surface of the ink receiving layer 3) on which the image and / or characters of the printed material 10 are formed via the gel-like material. A smooth film is laminated. Next, the printed material 10 on which the film is bonded is placed on a smooth table or the like so that the film is on the bottom, and is heated in advance by a household iron or the like heated to a temperature equal to or higher than the MFT of the treatment liquid. The surface is heated and pressurized from above (the surface of the water-resistant substrate 2 opposite to the ink receiving layer 3). At that time, it is preferable to uniformly heat and press the entire printed matter 10. By the heating and pressurizing treatment, the printed material 10 is dried, the water remaining in the gel-like material is completely evaporated and removed, and the resin fine particles are melted to have a certain fluidity. Become. Then, the melt is disposed on the entire surface of the ink receiving layer 3 with a uniform thickness, and the film is adhered to the printed material 10. The degree of drying is such that the moisture content of the printed material 10 after drying is preferably 10% by weight or less, more preferably 6% by weight or less.
[0038]
The film is preferably a polyethylene terephthalate (PET) resin film, a polyethylene (PE) resin film, a polypropylene (PP) resin film, or the like from the viewpoints of easy handling, cost, and safety in the film bonding step. The thickness of the film is preferably 10 to 100 μm, more preferably 25 to 50 μm.
[0039]
The printed material 10 that has undergone the film bonding step is first cooled to room temperature in the film peeling step. At that time, the melt is solidified to form the resin layer between the film and the ink receiving layer 3. Thereafter, the film is peeled off.
[0040]
As shown in FIG. 2, the printed matter 10 processed as described above has a thickness of preferably 1 to 50 μm, more preferably 5 to 25 μm on the ink receiving layer 3 on which an image or the like is formed. Coated. In order to set the thickness of the protective layer 4 within the above range, the solid content concentration and viscosity of the treatment liquid, the immersion time in the treatment liquid, and the like may be adjusted. In order to form the above-mentioned treatment liquid, the coating amount (coating amount) is 3 to 25 g / m. ² Thus, the protective layer having the above thickness is formed, and the oxygen permeability of the protective layer is 10 cc / (m ² -It is preferable to adjust so that it may become below D * atm). Furthermore, at that time, 2 to 15 g / m in terms of coating amount of the resin. ² And the oxygen permeability of the protective layer is 10 cc / (m ² (D · atm) It is preferable to adjust the treatment liquid so as to be less than or equal to D · atm. 15g / m ² Without super coating, oxygen permeability is 10cc / (m ² A resin that does not fall below D · atm) is not preferable because the surface properties of the printed matter after treatment are deteriorated. By providing such a protective layer 4 on the ink receiving layer 3, the printed matter 10 can be provided with sufficient light resistance and gas resistance.
Further, as described above, the protective layer 4 is formed by depositing a film on the fine particles of the resin adhering to the ink receiving layer 3 and then melting and forming the fine particles of the resin. The surface becomes a beautiful one with a glossiness improved by picking up the mirror surface of the film.
[0041]
The printed material 10 that is the target of the deterioration prevention method of the present embodiment may be a printed material in which an image and / or characters are formed with a dye ink on a recording medium in which an ink receiving layer is provided on a water-resistant substrate. Particularly preferred embodiments are as follows.
As the water-resistant substrate 2, RC paper (silver salt photographic substrate) is preferable, and its basis weight is preferably 150 to 300 g / m. ² More preferably, 200 to 250 g / m ² It is.
[0042]
The ink receiving layer 3 preferably contains gas phase method silica as the pigment, and the average particle size thereof is 0.01 to 1 μm, particularly 0.1 to 0.5 μm. It is preferable in terms of improvement in image quality such as smoothness and resolution, and its specific surface area by BET is 150 to 350 m. ² / G, especially 250-300m ² / G is preferable from the viewpoint of ink absorbability.
[0043]
The ink receiving layer 3 is 30 to 80% by weight, particularly 50 to 70% by weight of vapor-phase silica as the pigment, and 20 to 60% by weight, especially 30 to 50% by weight of polyvinyl alcohol as the binder, in terms of solid content. It is preferable in terms of water resistance and moisture resistance to contain 5 to 30% by weight, particularly 10 to 20% by weight of a secondary amine epihalohydrin polymer as a dye fixing agent as the auxiliary.
The coating amount of the ink receiving layer 3 on the water-resistant substrate 2 is 5 to 40 g / m in terms of solid content. ² Is preferred, 10-30 g / m ² More preferably. The thickness of the ink receiving layer 3 itself is preferably 5 to 80 μm, more preferably 20 to 60 μm.
[0044]
It is preferable that an image and / or characters are formed on the printed matter 10 that is a target of the degradation prevention method of the present embodiment by an inkjet printer.
[0045]
The method for preventing deterioration of printed matter of the present invention is not limited to the above-described embodiment, and various modifications can be made. For example, as a method of processing the printed material 10 with the processing liquid, in the embodiment, the printed material 10 is immersed in the processing liquid, but the processing liquid is sprayed on the printed material 10 using a spray or the like. do it Also good.
[0046]
Moreover, in the said film adhesion process, although the smooth film was bonded to the printed matter 10, you may bond the film with which the specific pattern was attached | subjected. By using such a film, a regular or irregular pattern can be given to the surface of the processed printed matter 10, and for example, a photo raster surface or silk surface can be made.
[0047]
Further, the protective layer 4 may be provided on the ink receiving layer 3, may be provided on one side of the water-resistant substrate 2, or may be provided on both sides.
When the protective layer 4 is provided on one side of the printed matter 10, a back coat layer may be provided in advance on the surface opposite to the ink receiving layer 3 of the water-resistant substrate 2 in order to prevent curling of the printed matter 10. Good.
[0048]
Further, the ink receiving layer 3 may be provided not only on one side of the water-resistant substrate 2 but also on both sides. Further, from the viewpoint of improving the image quality, the ink receiving layer 3 may be subjected to a smoothing process using a known calendar device.
Further, in place of the ink receiving layer 3 in the embodiment, for example, as described in JP-A-11-58942, a layer provided with voids containing inorganic fine particles bonded with an organic cationic polymer, As described in JP-A-11-115308, the water-soluble resin is crosslinked and cured while showing a constant rate of drying using inorganic fine particles, a water-soluble resin, and a specific crosslinking agent. The layer obtained by this can also be used. In addition, JP-A Nos. 10-81064, 10-1000039, 10-119420, 10-119423, 10-119424, 10-175365, 10-19376 Ink described in JP-A-10-203006, JP-A-10-217601, JP-A-11-20300, JP-A-11-20306, JP-A-7-276789, JP-A-8-174992, and the like. It can also be changed to a layer for acceptance.
[0049]
In addition, as a method for forming an image or the like on the recording medium 1, the inkjet recording method is used in the above embodiment, but any method that can form an image or the like using a dye ink may be used. For example, a sublimation thermal transfer method, An image or the like may be formed using a melt-type thermal transfer method or the like.
[0050]
The method for preventing deterioration of a printed material according to the present invention comprises forming a protective layer of the treatment liquid on the surface of the printed material by treating the printed material, which is the object, with a specific processing solution, and protecting the light and gas resistance of the printed material. Is to improve. Therefore, the form of the protective layer formed on the surface of the printed material by the method of the present invention is such that the dried material formed by drying a specific treatment liquid covers the image and / or characters of the printed material from the outside air. Any form is acceptable.
[0051]
【Example】
Below, the Example of the deterioration prevention method of the printed matter of this invention is shown. However, it goes without saying that the present invention is not limited to such examples. In the following examples, “parts” and “%” represent parts by weight and% by weight unless otherwise specified.
[0052]
[Example 1]
Printed products A and B obtained by the production methods of the following printed products A and B, respectively, were immersed in the treatment liquid obtained in the following Production Example 1 for 5 seconds, and then pulled up to 80 ° C. with a household dryer ( The treatment liquid was heated at a temperature lower than the MFT) and preliminarily dried. Thereafter, a PET film having a thickness of 25 μm (no corona treatment, manufactured by Unitika) was bonded so as to cover the entire surface (the surface of the ink receiving layer) on which images and / or characters of each printed matter were formed. Then, each printed matter is placed on a smooth table so that the film is on the bottom, and the whole printed matter is obtained by a domestic iron preheated to 140 ° C. (temperature equal to or higher than the MFT of the treatment liquid). Were each heated and pressurized uniformly to adhere the film and to dry each printed matter. After each print was cooled to room temperature, the film was peeled off to obtain treated prints A1 and B1 (both containing 7% by weight). In any case, the coating amount is 5 to 10 g / m. ² Met.
[0053]
[Production method of printed matter A]
As a recording medium in which an ink receiving layer is provided on a water-resistant substrate, a commercially available inkjet recording medium (trade name “PM Photo Paper”, manufactured by EPSON) is used, and a dye ink (C, M, Y, A color patch was printed using an ink jet printer (trade name “PM800C”, manufactured by Seiko Epson Corporation) using a Bk4 color 100% patch, and a printed material A was obtained.
[0054]
[Production method of printed matter B]
A high-definition color digital standard image [(ISO / JIS-SCID) is obtained by the PM800C using the same dye ink as used in the printed material manufacturing method A on a recording medium similar to that used in the printed material manufacturing method A. ) And image name “Portrait” (sample number 1, image evaluation recognition number N1)] were printed to obtain a printed matter B.
[0055]
[Comparative Examples 1-4]
In place of the following treatment liquids in Example 1, the treatment liquids A′1 to A′4 and Comparative treatment printed materials A′1 to A′4 and B′1 to B′4 were obtained.
[0056]
[Production Example 1]
250 parts of water, 96.5 parts of a polyolefin resin emulsion (solid concentration 40%, trade name “Chemical”, manufactured by Mitsui Chemicals), 3 parts of a water-soluble UV absorber (trade name “Needral”, manufactured by Taki Chemical) 0.5 part of an ink fixing agent (trade name “SUMIREZ RESIN 1001”, manufactured by Sumitomo Chemical Co., Ltd.) was added and mixed to obtain a treatment liquid having a solid content concentration of 28.5% and a viscosity of 50 cps.
[0057]
[Comparative Production Example 1]
A treatment liquid having a solid content concentration of 25.5% and a viscosity of 45 cps was obtained in the same manner as in Production Example 1 except that water was used instead of the water-soluble ultraviolet absorber in Production Example 1.
[0058]
[Comparative Production Example 2]
A treatment liquid having a solid content concentration of 25% and a viscosity of 44 cps was obtained in the same manner as in Production Example 1 except that water was used in place of the water-soluble ultraviolet absorber and the ink fixing agent in Production Example 1.
[0059]
[Comparative Production Example 3]
The solid content concentration was 28.5% in the same manner as in Production Example 1 except that an acrylic resin emulsion (solid content concentration 40%, trade name “Bonlon”, manufactured by Mitsui Chemicals) was used instead of the polyolefin resin emulsion in Production Example 1. A treatment liquid having a viscosity of 48 cps was obtained.
[0060]
[Comparative Production Example 4]
A solid content concentration of 13.5% was obtained in the same manner as in Production Example 1 except that 10 parts of starch (trade name “MS3800”, manufactured by Nippon Food Processing) and 100 parts of water were used instead of the polyolefin resin emulsion in Production Example 1. A treatment liquid having a viscosity of 95 cps was obtained.
[0061]
[Evaluation of processability, gas resistance, image quality change, water resistance, moisture resistance and light resistance]
For each of the treated printed matter A1 obtained in Example 1 and the comparatively treated printed matter A′1 to A′4 obtained in Comparative Examples 1 to 4, the following [Evaluation Criteria for Treatability] and [Gas Resistance Evaluation was performed according to [Evaluation Criteria] and [Evaluation Criteria for Image Quality Change]. The results are shown in Table 1 below. In addition, about [Water resistance evaluation] and [Moisture resistance evaluation], it is performed only for the treated printed matter A1 and the comparatively treated printed matter A′1, A′3 and A′4, and the following [Waterproofness evaluation criteria] and [Evaluation criteria for moisture resistance]
Further, each of the processed printed material B1 obtained in Example 1 and the comparative processed printed materials B′1 to B′4 obtained in Comparative Examples 1 to 4 were evaluated according to the following [light resistance evaluation criteria]. The results are shown in Table 1 below.
[0062]
[Evaluation criteria for processability]
The “surface state” and “the degree of dye oozing” of each of the treated printed material A1 and the comparative treated printed materials A′1 to A′4 were visually observed and evaluated according to the following evaluation criteria. The “surface state” is for the surface state immediately after film peeling, and the “degree of dye oozing” is for before film bonding (after preliminary drying).
[Evaluation criteria for surface condition]
○: Glossiness is improved compared to before treatment.
(Triangle | delta): There are some unevenness | corrugations compared with before a process. Practical limit.
X: Cloudiness, cracks, and irregularities are generated as compared with before treatment, impractical.
XX: When the film is peeled off, the substrate is broken or the ink receiving layer is peeled off.
[Evaluation criteria for the degree of dye oozing]
○: No bleeding is observed at all.
X: Bleeding of at least one color among C, M, Y, and Bk can be observed.
[0063]
[Evaluation criteria for gas resistance]
Each of the treated printed matter A1 and the comparative treated printed matter A′1 to A′4 is put into a glass container having a gas inlet and an outlet, and a mixed gas generated by a gas generator (ozone 1 ppm, NO ₂ 5ppm, SO ₂ 1 ppm) was continuously introduced for 30 minutes for gas treatment. Using the color difference meter, the color difference (average values for C, M, and Y3 colors) for the processed printed material before each gas processing and each comparative processed printed material is determined for each processed printed material after gas processing and each comparative processed printed material. It was evaluated by.
〔Evaluation criteria〕
○: Color difference is less than 5. Good gas resistance.
Δ: Color difference is 5 or more and less than 15. Practical limit.
X: Color difference is 15 or more. Unbearable for practical use.
[0064]
[Evaluation criteria for image quality variability]
For each of the printed matter A (before treatment), the treated printed matter A1 and the comparative treated printed matter A′1 to A′4 (after treatment), the reflection density is measured using a reflection density measuring device (“SPM50-1”, manufactured by Gretag Macbeth). Then, the OD change rate (average value for C, M, Y3 colors) was obtained and evaluated according to the following evaluation criteria.
〔Evaluation criteria〕
○: OD change rate is 5% or less.
Δ: OD change rate is less than 10%.
X: OD change rate is 10% or more.
[0065]
[Evaluation criteria for water resistance]
The treated printed matter A1 and the comparative treated printed matter A′1, A′3 and A′4 were left in an environment of a temperature of 25 ° C. and a relative humidity of 50% for 24 hours, and then 0.3 cc of water droplets were added to the respective C, M , Y, Bk patches were dropped onto a 100% portion, and further left in an environment of a temperature of 25 ° C. and a relative humidity of 50% for 24 hours. Thereafter, the above-mentioned “degree of dye oozing” for each of the processed printed material A1 and the comparative processed printed materials A′1, A′3, and A′4 was visually observed and evaluated according to the following evaluation criteria.
〔Evaluation criteria〕
○: No bleeding is observed at all. Good water resistance.
Δ: Bleeding of two colors of C, M, Y, and Bk can be observed. Practical limit.
X: Bleeding of three or more colors among C, M, Y, and Bk can be observed. Unbearable for practical use.
[0066]
[Evaluation criteria for moisture resistance]
The treated printed matter A1 and the comparative treated printed matter A′1, A′3 and A′4 were left to stand for 24 hours in an environment at a temperature of 25 ° C. and a relative humidity of 50%, and then subjected to a drying treatment. Wet treatment was performed by leaving it in an 80% environment for 24 hours. Using the color difference meter for each of the image background portions of the processed printed material A1 after the wet treatment and the comparative processed printed materials A′1, A′3, and A′4, the processed printed material A1 and the comparative processed printed material before the wet processing (after the drying processing). Color differences (average values for C, M, and Y3 colors) for A′1, A′3, and A′4 were determined and evaluated according to the following evaluation criteria.
〔Evaluation criteria〕
○: Color difference is less than 5. Good moisture resistance.
Δ: Color difference is 5 or more and less than 10. Practical limit.
X: Color difference is 10 or more. Unbearable for practical use.
[0067]
[Evaluation criteria for light resistance]
Using the xenon weatherometer Ci35A (manufactured by ATLAS) for each of the treated print B1 and the comparative treated prints B′1 to B′4, the radiation energy of 340 nm is 0.25 W / m. ² In a black panel temperature of 63 ° C. and a relative humidity of 50% RH, 45 kJ / m ² The light exposure treatment was performed. For each of the image background portions of the processed print B1 after the light exposure treatment and the comparative processed prints B′1 to B′4, using a color difference meter, the processed print B1 before the light exposure treatment and the comparative processed prints B′1 to B ′. The color differences (average values for the C, M, Y3 colors and the image background portion) for each of the four were determined and evaluated according to the following evaluation criteria.
〔Evaluation criteria〕
○: Color difference is less than 5. Good light resistance.
Δ: Color difference is 5 or more and less than 10. Practical limit.
X: Color difference is 10 or more. Unbearable for practical use.
[0068]
[Measurement of oxygen permeability]
The oxygen transmission rate of each of the processed printed material A1 and the comparative processed printed materials A′1 to A′4 in an environment of a temperature of 20 ° C. and a relative humidity of 90% was measured according to ASTM-D-1434. The results are shown in Table 1 below.
[0069]
[Measurement of MFT]
The MFTs of the treatment liquids obtained in Production Example 1 and Comparative Production Examples 1 to 4 were measured according to JIS K 6800. The results are shown in Table 1 below.
[0070]
[Table 1]

[0071]
As is apparent from the results shown in Table 1, the printed matter treated with the treatment liquid (Production Example 1) according to the method for preventing deterioration of a printed matter of Example 1 was treated, treated with gas, improved in image quality, resistant to water and moisture. It can be seen that it is excellent in all of properties, light resistance and oxygen permeability. On the other hand, according to the printed matter deterioration prevention method of Comparative Examples 1 to 4, all the printed materials treated with the treatment liquid (Comparative Production Examples 1 to 4) have processability, gas resistance, image quality change property, water resistance, and moisture resistance. It can be seen that either the property or the oxygen permeability has not reached a sufficient level. In addition, in the deterioration prevention method of the printed matter of Example 1, the printed matter was impregnated into the printed matter by immersing the printed matter in the treating solution, but instead of “immersion into the treating solution”. The same result was obtained even when the printed matter was impregnated with the treatment liquid by “spraying of the treatment liquid by spraying”.
[0072]
Further, from the comparison between Example 1 and Comparative Examples 1 and 2, in order to improve the gas resistance and light resistance of the printed matter without changing the image quality, a resin that is an essential component of the treatment liquid of the present invention, It can be seen that a light fastness improver and an ink fixing agent are necessary.
Further, it can be seen from the comparison between Example 1 and Comparative Example 3 that the MFT of the treatment liquid needs to be equal to or higher than a certain temperature in order to improve the glossiness of the printed matter after the treatment. In Comparative Example 3, since the printed matter was processed with a processing liquid having a low MFT, the resin dispersed in the processing liquid was melted and formed into a film by preliminary drying with a household dryer, and the film bonding / adhesion was cleaned in the next step. Could not do.
Further, it can be seen from the comparison between Example 1 and Comparative Example 4 that the treatment liquid needs to contain a resin having an oxygen permeability of a certain value or less in a dispersed state.
[0073]
【The invention's effect】
According to the method for preventing deterioration of a printed matter of the present invention, the deterioration of the printed matter is improved, in particular, the light resistance and gas resistance of the printed matter are improved with almost no change in image quality, and ultraviolet light, visible light, oxidizing gas, etc. The printed material can be prevented from discoloration and discoloration, and can be performed with a household dryer or a domestic iron without using a special device. be able to. Further, the printed matter after the deterioration prevention treatment has a beautifully polished surface with a glossy finish.
[Brief description of the drawings]
FIG. 1 is an enlarged cross-sectional view showing an enlarged cross section of a printed material used in the method for preventing deterioration of a printed material according to the present invention.
FIG. 2 is an enlarged cross-sectional view showing an enlarged cross section of a printed material after being processed by the method for preventing deterioration of a printed material according to the present invention.
[Explanation of symbols]
1 Recording medium
2 Water resistant substrate
3 Ink receiving layer
4 Protective layer
10 Printed matter

Claims

A method for preventing deterioration of a printed material, wherein a printed material in which an image and / or characters are formed with a dye ink on a recording medium having an ink-receiving layer provided on a water-resistant substrate, is treated with a treatment liquid,
The treatment liquid resin is a water-based dispersion of the resin containing a light fastness improving agent and the ink fixing agent, the minimum film forming temperature of that is at 70 ° C. or higher,
The resin is a printed material [water-resistant paper having a water-resistant substrate of a recording medium having an oxygen permeability of 30 cc / (m ² · D · atm) or more in an environment where the temperature is 20 ° C. and the relative humidity is 90%, and the ink The resin is applied at a coating amount of 15 g / m ² on the surface of the image of the printed material on which the image is formed with the dye ink on the receiving layer], so that the printed material has an environment of 20 ° C. and 90% relative humidity. oxygen permeability ^{10cc / (m 2 · D ·} atm) Ri resin der capable below,
The treatment with the treatment liquid is performed by immersing the printed matter before treatment in the treatment liquid, and heating the printed matter that has undergone the immersion step at a temperature lower than the minimum film-forming temperature of the aqueous dispersion. A pre-drying step for pre-drying, a film is adhered to one surface on which images and / or characters of the printed matter that have undergone the pre-drying step are formed, and the printed matter is at a temperature equal to or higher than the minimum film-forming temperature of the aqueous dispersion. The deterioration prevention method of printed matter provided with the film adhesion process which heats and dries and the film peeling process which peels the said film from the said printed matter .

The method for preventing deterioration of a printed matter according to claim 1, wherein the treatment liquid contains 30 to 98% by weight of the resin, 0.01 to 25% by weight of the light fastness improver, and 0.5 to 25% by weight of the ink fixing agent. .

The method for preventing deterioration of printed matter according to claim 1 or 2, wherein the treatment liquid further contains an inorganic pigment, and the content of the inorganic pigment is 1 to 50% by weight.

The resin is polyolefin resin, (meth) acrylic acid resin, styrene-butadiene resin, vinyl chloride resin, styrene-acrylic resin, butadiene resin, styrene resin, phenol resin, silicon resin, urethane resin. The method for preventing deterioration of a printed matter according to any one of claims 1 to 3, which is one or more selected from the group consisting of epoxy resins.

The method for preventing deterioration of printed matter according to any one of claims 1 to 4, wherein the light resistance improver is one or more selected from the group consisting of an ultraviolet absorber and a hindered amine light stabilizer.

The method for preventing deterioration of printed matter according to any one of claims 1 to 5, wherein the ink fixing agent is one or more selected from the group consisting of cationic organic substances.

Was treated with the treatment liquid, the printed matter obtained by drying, on the ink-receiving layer so as to include a protective layer having a thickness of 1 to 50 [mu] m, to any one of claims 1 to 6, treatment with the treating solution The method for preventing deterioration of the printed matter.

The method for preventing deterioration of printed matter according to any one of claims 1 to 7 , wherein the printed matter is ink-jet recorded on the recording medium with the dye ink.

A treatment liquid used in the method for preventing deterioration of printed matter according to any one of claims 1 to 8 ,
An aqueous dispersion of the resin containing a resin, a light fastness improver, and an ink fixing agent. The aqueous dispersion has a minimum film-forming temperature of 70 ° C. or higher, and the resin is a printed material [water resistance in a recording medium]. The water-resistant substrate is a water-resistant paper having an oxygen transmission rate of 30 cc / (m ² · D · atm) or more in an environment of a temperature of 20 ° C. and a relative humidity of 90%, and an image is formed on the ink receiving layer with a dye ink. By applying the resin to the surface of the image of [printed material] at a coating amount of 15 g / m ² , the oxygen transmission rate of the printed material in an environment of a temperature of 20 ° C. and a relative humidity of 90% is 10 cc / (m ² · D · atm) a treatment liquid that can be made lower than the following.