JP2004090513A - Inkjet recording material and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording material and its manufacturing method, in which the quality of an image formed thereby is good and the drying characteristics of image surface is excellent and, in addition, no crack develops in the ink accepting layer thereof. <P>SOLUTION: This inkjet recording material is formed by providing a coating layer, which includes at least a silanol-modified polyvinyl alcohol (A1), a polyvinyl alcohol (A2), the degree of polymerization of which is at least 2,000 and which is not modified by the silanol, and silica particles under the condition that the mass ratio (A1/A1+A2) of A1 and A2 is set to be 0.25-0.75 on a base material. <P>COPYRIGHT: (C)2004,JPO

Description

【００２４】
実際には、例えばＲ１１３０（クラレ社製）の如く、市販されているものもある。ちなみにＲ１１３０の重合度は１７００、ｎ；約９９、ｍ；０〜１のシラノール変性ポリビニルアルコール（ｐは０ではない）といわれている。
【００２５】
前記したインク受容層の親水性バインダーとしては、透明性が高くインクの高い浸透性が得られるバインダーが好ましく用いられ、その意味から本発明では親水性バインダーとして、重合度が２０００以上のシラノール変成されていないポリビニルアルコール（Ａ２）が用いられる。
【００２６】
特に好ましいのは、ケン化度が８０以上の部分または完全ケン化したものであり、平均重合度２５００〜６０００のポリビニルアルコールが好ましい。市販されているものとしては、下記一般式（Ａ２）において、ｎ；９０、ｍ；１０で重合度３５００、４３００（いずれもクラレ社製、ＰＶＡ２３５、２４５）等がある。
【００２７】
【化２】

【００２８】
上記したポリビニルアルコール等の親水性バインダーは、無機微粒子に対して、小さい比率で用いる方がインク受容性の点で好ましいが、あまりに少ないとひび割れが発生しやすくなる。
【００２９】
本発明は、親水性バインダー量を、シリカ粒子に対して、３０質量％以下の小さい比率で用いても、ひび割れを防止できることが最大の特長である。従って、本発明において、親水性バインダー量は、シリカ粒子に対して３０質量％以下、好ましくは１０〜２７質量％の範囲で用いるのが好ましい。
【００３０】
本発明において好ましい態様は、無機微粒子として気相法シリカを１０〜３０ｇ／ｍ^２、バインダーとしてポリビニルアルコールを気相法シリカに対して１０〜３０質量％、架橋剤としてほう酸もしくはほう酸塩を用いることである。
【００３１】
本発明は、ほう酸もしくはほう酸塩を塗布直前に後述するインライン添加するのも好ましい態様である。インライン添加されるほう酸は、全ほう酸量の一部であっても全量であってもよい。ほう酸の好ましい添加量は、気相法シリカの粒子径や添加量、及びポリビニルアルコールの量によって変わるが、ポリビニルアルコールに対して、５〜３５質量％が適当である。好ましくは８〜３０質量％の範囲である。
【００３２】
ほう酸のインライン添加用の溶液は、ほう酸の濃度が１〜１０質量％程度になるように、水を主体とする溶媒に溶解して作られる。インライン添加する場合は濃度に応じて、流量を設定し、流量計で制御された所定量の塗布液中に添加される。
【００３３】
更に、本発明のインク受容層は、カチオン性化合物を含有するのが好ましい。カチオン性化合物としては、例えばカチオン性ポリマーや水溶性金属化合物が挙げられる。カチオン性ポリマーとしては、ポリエチレンイミン、ポリジアリルアミン、ポリアリルアミン、ポリアルキルアミン重合物、特開昭６３−２８０６８１号、特開平１−４０３７１号、同６−２３４２６８号、同７−１２５４１１号、同１０−１９３７７６号公報等に記載された１〜３級アミノ基、４級アンモニウム塩基を有するポリマーが好ましく用いられる。これらのカチオンポリマーの分子量は、５，０００以上が好ましく、更に５，０００〜１０万程度が好ましい。
【００３４】
これらのカチオン性ポリマーの使用量はシリカ粒子に対して１〜１０質量％、好ましくは２〜７質量％である。
【００３５】
塗布液は、通常、シリカ粒子を高圧ホモジナイザー、高速ホモジナイザー、ボールミル等で水中に分散し、該分散液と親水性バインダー、架橋剤、界面活性剤等を混合して作製される。生産効率を上げるためには、１回に多量の塗布液を作製し、連続塗布することが好ましい。従って、１回に製造された塗布液量は、長時間かけて基材に塗布される。例えば５時間、更には１０時間を越える場合がある。塗布液を作製して塗布が終了するまでの間、塗布液は３０〜４５℃程度の温度に保温されて経時される。
【００３６】
塗布液は、通常、１バッチ当たり数百リットル〜数千リットルの単位で製造され、貯留釜（タンク）に一旦貯留され、貯留釜からポンプやヘッド差（高低差）を利用し、パイプ等の送液管を通じて塗布装置に供給されて支持体に塗布される。
【００３７】
従来は塗布液製造時にインク受容層の構成成分は全て添加され、完全な塗布液の形で塗布装置に供給されている場合が多かった。しかし、本発明では、シラノール変成ポリビニルアルコール（Ａ１）の一部もしくは全部を添加せずに塗布液を製造し、該塗布液を塗布する直前に架橋剤を塗布液中に添加混合する方が好ましい。
【００３８】
具体的には、Ａ１の一部もしくは全部を、貯留釜から塗布装置へ塗布液が送液される経路で、該塗布液に添加混合する。
【００３９】
この方法は、インライン添加とも称されており、そのための混合装置も、インラインミキサーやスタティックミキサーとして市販されている。例えば、Ｋｅｎｉｃｓ社（アメリカ）製のスタティックミキサー、Ｓｕｌｇｅｒ社（スイス）製のスタティックミキシングエレメントＳＭＶ型、晃立工業社製のシマザキパイプミキサー、東レ社製のＨｉ−Ｍｉｘｅｒ、ノリタケ社製のスタティクミキサーＮ１０等がある。また、インライン動的ミキサーとしては、特願平１１−８０６５５号に記載のものを用いることもできる。
【００４０】
本発明の好ましい一態様例として、塗布直前に添加する工程を図を用いて更に詳細に説明する。
【００４１】
図１はインク受容層の製造装置の模式図である。貯留釜１に貯留された塗布液は、ヘッド差（塗布液の粘度が高い場合は図示しないポンプを併用することができる）を利用しパイプ２を通して降下される。一方、貯留釜３には、Ａ１を含有する溶液がインライン添加液として貯留されており、同様にヘッド差を利用しパイプ４を通して降下される。降下された塗布液及びＡ１は、それぞれ流量計５、６で所定の流量に制御された後、インラインミキサー７で混合され完全な塗布液となって、塗布装置８に送液されて支持体に塗布される。
【００４２】
次に、インク受容層の構成について説明する。本発明のインク受容層は、シリカ粒子を主に含有するものである。他に無機微粒子として、炭酸カルシウム、炭酸マグネシウム、カオリン、クレー、タルク、硫酸カルシウム、硫酸バリウム、二酸化チタン、酸化亜鉛、ハイドロタルサイト、ケイ酸アルミニウム、ケイソウ土、ケイ酸カルシウム、合成シリカ、コロイダルシリカ、アルミナ、擬ベーマイト等を含有させてもよい。
【００４３】
上記、シリカ粒子の中でも、合成シリカが好ましく、特に気相法シリカが好ましく用いられる。合成シリカには、湿式法によるものと気相法によるものがある。通常シリカ微粒子といえば湿式法シリカを指す場合が多い。湿式法シリカとしては、（１）ケイ酸ナトリウムの酸などによる複分解やイオン交換樹脂層を通して得られるシリカゾル、また（２）このシリカゾルを加熱熟成して得られるコロイダルシリカ、（３）シリカゾルをゲル化させ、その生成条件を変えることによって数ミクロンから１０ミクロン位の一次粒子がシロキサン結合した三次元的な二次粒子となったシリカゲル、更には（４）シリカゾル、ケイ酸ナトリウム、アルミン酸ナトリウム等を加熱生成させて得られるもの等のケイ酸を主体とする合成ケイ酸化合物がある。
【００４４】
本発明において、好ましく用いられる気相法シリカは、湿式法に対して乾式法とも呼ばれ、一般的には火炎加水分解法によって作られる。具体的には四塩化ケイ素を水素及び酸素と共に燃焼して作る方法が一般的に知られているが、四塩化ケイ素の代わりにメチルトリクロロシランやトリクロロシラン等のシラン類も、単独または四塩化ケイ素と混合した状態で使用することができる。気相法シリカは、アエロジル（日本アエロジル社製）、ＱＳタイプ（トクヤマ社製）として市販されており容易に入手することができる。
【００４５】
本発明に用いられる気相法シリカの一次粒子の平均粒径は、３０ｎｍ以下が好ましく、より高い光沢を得るためには、３〜１０ｎｍでかつＢＥＴ法による比表面積が２５０ｍ^２／ｇ以上（好ましくは２５０〜５００ｍ^２／ｇ）のものを用いるのが好ましい。本発明で云うＢＥＴ法とは、気相吸着法による粉体の表面積測定法の一つであり、吸着等温線から１ｇの試料の持つ総表面積、即ち比表面積を求める方法である。
【００４６】
通常吸着気体としては、窒素ガスが多く用いられ、吸着量を被吸着気体の圧、または容積の変化から測定する方法が最も多く用いられている。多分子吸着の等温線を表すのに最も著名なものは、Ｂｒｕｎａｕｅｒ、Ｅｍｍｅｔｔ、Ｔｅｌｌｅｒの式であってＢＥＴ式と呼ばれ表面積決定に広く用いられている。ＢＥＴ式に基づいて吸着量を求め、吸着分子１個が表面で占める面積を掛けて、表面積が得られる。
【００４７】
上記気相法シリカの特徴は、一次粒子が網目構造または鎖状につながりあって二次的に凝集した状態で存在することであり、これによって、高いインク受容性が得られる。前記二次凝集の状態は５０〜５００ｎｍ程度に保つことが好ましく、これによって、光沢を低下させずに高いインク受容性が得られる。
【００４８】
本発明において、インク受容層に含有させるシリカ粒子の量は、８ｇ／ｍ^２以上が好ましく、１０〜３０ｇ／ｍ^２の範囲がより好ましい。
【００４９】
本発明において、シリカ粒子を含有するインク受容層は、皮膜としての特性を維持するために他のバインダーを併用してもよい。このバインダーとしては、公知の各種親水性バインダーを用いることができる。例えば、ゼラチン及びその誘導体、ポリビニルピロリドン、プルラン、ポリエチレングリコール、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、デキストラン、デキストリン、ポリアクリル酸及びその塩、寒天、カラギーナン、キサンテンガム、ローカストビーンガム、アルギン酸、アラビアゴム、水溶性ポリビニルブチラール、あるいは、カルボキシ基やスルホン酸基を有するビニルモノマーの単独または共重合体等を挙げることができる。
【００５０】
本発明におけるインク受容層は、皮膜の脆弱性を改良するために各種油滴を含有することができる。そのような油滴としては室温における水に対する溶解性が０．０１質量％以下の疎水性高沸点有機溶媒（例えば、流動パラフィン、ジオクチルフタレート、トリクレジルホスフェート、シリコーンオイル等）や重合体粒子（例えば、スチレン、ブチルアクリレート、ジビニルベンゼン、ブチルメタクリレート、ヒドロキシエチルメタクリレート等の重合性モノマーを一種以上重合させた粒子）を含有させることができる。そのような油滴は好ましくは親水性バインダーに対して１０〜５０質量％の範囲で用いることができる。
【００５１】
本発明において、インク受容層には、界面活性剤を添加することができる。界面活性剤の添加量はインク受容層を構成するポリビニルアルコール等のバインダー１００ｇに対して０．００１〜５ｇが好ましく、より好ましくは０．０１〜３ｇである。
【００５２】
本発明において、インク受容層には、更に着色染料、着色顔料、インク染料の定着剤、紫外線吸収剤、酸化防止剤、顔料の分散剤、消泡剤、レベリング剤、防腐剤、蛍光増白剤、粘度安定剤、ｐＨ調節剤などの公知の各種添加剤を添加することもできる。
【００５３】
本発明において、インク受容層の塗布方法は、特に限定されず、公知の塗布方法を用いることができる。例えば、スライドビード方式、カーテン方式、エクストルージョン方式、エアナイフ方式、ロールコーティング方式、ケッドバーコーティング方式等がある。上記塗布方式の中でも、特にスライドビード方式、カーテン方式、エクストルージョン方式が好ましく用いられる。
【００５４】
本発明において、インクジェット記録用紙は基材上に、少なくとも１層のインク受容層を設けた構成であるが、さらに第２のインク受容層、インク定着層、中間層、保護層等を設けてもよい。
【００５５】
本発明に用いられる基材（支持体）としては、耐水性支持体が好ましく用いられ、例えばポリエチレンテレフタレートやポリエチレンナフタレートのようなポリエステル樹脂、ジアセテート樹脂、トリアセテート樹脂、アクリル樹脂、ポリカーボネート樹脂、ポリ塩化ビニル、ポリイミド樹脂、セロハン、セルロイド等の樹脂フィルム、また、ポリエチレンやポリプロピレン等のポリオレフィン樹脂で紙を被覆（ラミネート）した支持体、更にガラス板等が挙げられる。
【００５６】
これらの支持体は、透明であっても不透明であってもよい。本発明に用いられる耐水性基材の厚みは、５０〜２００μｍ程度のものが好ましい。
【００５７】
本発明において特に好ましい基材は、ポリエチレンテレフタレートやポリオレフィン樹脂被覆紙である。
【００５８】
以下、ポリオレフィン樹脂被覆紙について詳細に説明する。
ポリオレフィン樹脂被覆紙を構成する原紙は、特に制限はなく、一般に用いられている紙が使用できるが、より好ましくは例えば写真用支持体に用いられているような平滑な原紙が好ましい。原紙を構成するパルプとしては天然パルプ、再生パルプ、合成パルプ等を１種もしくは２種以上混合して用いられる。この原紙には一般に製紙で用いられているサイズ剤、紙力増強剤、填料、帯電防止剤、蛍光増白剤、染料等の添加剤が配合されている。
【００５９】
さらに、表面サイズ剤、表面紙力剤、蛍光増白剤、帯電防止剤、染料、アンカー剤等が表面塗布されていてもよい。
【００６０】
また、原紙の厚みに関しては特に制限はないが、紙を抄造中または抄造後カレンダー等にて圧力を印加して圧縮するなどした表面平滑性の良いものが好ましく、その坪量は３０〜２５０ｇ／ｍ^２が好ましい。
【００６１】
樹脂被覆紙の樹脂としては、ポリオレフィン樹脂や電子線で硬化する樹脂を用いることができる。ポリオレフィン樹脂としては、低密度ポリエチレン、高密度ポリエチレン、ポリプロピレン、ポリブテン、ポリペンテンなどのオレフィンのホモポリマーまたはエチレン−プロピレン共重合体などのオレフィンの２つ以上からなる共重合体及びこれらの混合物であり、各種の密度、溶融粘度指数（メルトインデックス）のものを単独にあるいはそれらを混合して使用できる。
【００６２】
又、樹脂被覆紙の樹脂中には、酸化チタン、酸化亜鉛、タルク、炭酸カルシウムなどの白色顔料、ステアリン酸アミド、アラキジン酸アミドなどの脂肪酸アミド、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などの脂肪酸金属塩、イルガノックス１０１０、イルガノックス１０７６などの酸化防止剤、コバルトブルー、群青、セシリアンブルー、フタロシアニンブルーなどのブルーの顔料や染料、コバルトバイオレット、ファストバイオレット、マンガン紫などのマゼンタの顔料や染料、蛍光増白剤、紫外線吸収剤などの各種の添加剤を適宜組み合わせて加えるのが好ましい。
【００６３】
本発明において好ましく用いられる基材である樹脂被覆紙は、走行する原紙上にポリオレフィン樹脂の場合は、加熱溶融した樹脂を流延する、いわゆる押出コーティング法により製造され、その両面が樹脂により被覆される。また、電子線により硬化する樹脂の場合は、グラビアコーター、ブレードコーターなど一般に用いられるコーターにより樹脂を塗布した後、電子線を照射し、樹脂を硬化させて被覆する。また、樹脂を原紙に被覆する前に、原紙にコロナ放電処理、火炎処理などの活性化処理を施すことが好ましい。支持体のインク受容層が塗布される面（表面）は、その用途に応じて光沢面、マット面などを有し、特に光沢面が優位に用いられる。裏面に樹脂を被覆する必要はないが、カール防止の点から樹脂被覆したほうが好ましい。裏面は通常無光沢面であり、表面あるいは必要に応じて表裏両面にもコロナ放電処理、火炎処理などの活性処理を施すことができる。また、樹脂被覆層の厚みとしては特に制限はないが、一般に５〜５０μｍの厚味に表面または表裏両面にコーティングされる。
【００６４】
本発明における基材には帯電防止性、搬送性、カール防止性などのために、各種のバックコート層を塗設することができる。バックコート層には無機帯電防止剤、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、界面活性剤など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】
次に、本発明の構成と効果を、実施例としてより具体的に示すが、無論本発明の態様は下記に限定されるわけではない。
【００６６】
尚、文中「部」とは「質量部」を表す。
〔実施例１〕
インクジェット記録用紙１−１（本発明外）
基材として、パルプからなる１２０ｇ／ｍ^２の紙の表面に低密度ポリエチレン（７０部）と高密度ポリエチレン（２０部）と酸化チタン（１０部）からなる樹脂組成物を２５ｇ／ｍ^２塗布し、裏面に高密度ポリエチレン（５０部）と低密度ポリエチレン（５０部）からなる樹脂組成物を２５ｇ／ｍ^２塗布してなる樹脂被覆紙を用いた。
【００６７】
下記に示すインク受容層塗布液は、気相法シリカが８質量％の固形分濃度になるように調製した。この塗布液を、３８℃で３時間経時した後、上記基材上にスライドビード塗布装置で湿分塗布量が２３８ｇ／ｍ^２になるように流量設定し、塗布乾燥した。これをインクジェット記録用紙１−１とする。
【００６８】
〈インク受容層塗布液１−１〉
気相法シリカ　　　　　　　　　　　　　　　　　　　　　　　１００部
（平均一次粒径７ｎｍ、ＢＥＴ法による比表面積３００ｍ^２／ｇ）
ジメチルジアリルアンモニウムクロライドホモポリマー　　　　　　２部
（シャロールＤＣ９０２Ｐ、分子量９０００；第一工業製薬社製）
塩基性ポリ水酸化アルミニウム　　　　　　　　　　　　　　　　　３部
（ピュラケムＷＴ；理研グリーン社製）
ほう酸　　　　　　　　　　　　　　　　　　　　　　　　　　　　８部
ポリビニルアルコール　　　　　　　　　　　　　　　　　　　　２５部
（ケン化度８８％、平均重合度３５００）
界面活性剤　　　　　　　　　　　　　　　　　　　　　　　　０．３部
インクジェット記録用紙１−２（本発明外）
上記インク受容層塗布液１−１のポリビニルアルコールを２０部とし、代わりにシラノール変性ポリビニルアルコール（Ｒ１１３０　平均重合度１７００；クラレ社製）を５部添加した以外は、インク受容層塗布液１−１と同様にしてインクジェット記録用紙１−２を作製した。
【００６９】
インクジェット記録用紙１−３（本発明内）
上記インク受容層塗布液１−１のポリビニルアルコールを１８部とし、代わりにシラノール変性ポリビニルアルコール（Ｒ１１３０　平均重合度１７００；クラレ社製）を７部添加した以外は、インク受容層塗布液１−１と同様にしてインクジェット記録用紙１−３を作製した。
【００７０】
インクジェット記録用紙１−４（本発明内）
上記インク受容層塗布液１−１のポリビニルアルコールを１２．５部とし、代わりにシラノール変性ポリビニルアルコール（Ｒ１１３０　平均重合度１７００；クラレ社製）を１２．５部添加した以外は、インク受容層塗布液１−１と同様にしてインクジェット記録用紙１−４を作製した。
【００７１】
インクジェット記録用紙１−５（本発明内）
上記インク受容層塗布液１−１のポリビニルアルコールを７部とし、代わりにシラノール変性ポリビニルアルコール（Ｒ１１３０　平均重合度１７００；クラレ社製）を１８部添加した以外は、インク受容層塗布液１−１と同様にしてインクジェット記録用紙１−５を作製した。
【００７２】
インクジェット記録用紙１−６（本発明外）
上記インク受容層塗布液１−１のポリビニルアルコールを５部とし、代わりにシラノール変性ポリビニルアルコール（Ｒ１１３０　平均重合度１７００；クラレ社製）を２０部添加した以外は、インク受容層塗布液１−１と同様にしてインクジェット記録用紙１−６を作製した。
【００７３】
インクジェット記録用紙１−７（本発明外）
上記インク受容層塗布液１−１のポリビニルアルコールを添加せず、代わりにシラノール変性ポリビニルアルコール（Ｒ１１３０　平均重合度１７００；クラレ社製）を２５部添加した以外は、インク受容層塗布液１−１と同様にしてインクジェット記録用紙１−７を作製した。
【００７４】
特性の評価
ひび割れ
インク受容層塗布乾燥後のインク受容層を有するインクジェット記録用紙１−１〜７の表面を肉眼にて注意深く観察し、ひび割れの状態を評価した。
【００７５】
シラノール変性ポリビニルアルコールを添加していないインクジェット記録用紙１−１を基準（２点）とし、良好なものほど点が増す５点法で評価付けをした。
【００７６】
評点
５；全く認められず
４；殆どなし
３；認められるがなんとか実用可能レベル
２；明らかに認められる
１；明らかに実用上問題あるレベル
表面乾燥性
フィルムカセットを有する特開２００１−２７７４８３公報の図１に記載されたインクジェット出力装置を用い、黒インクで全面印字しながら、その乾燥性を観察した。
【００７７】
インクジェット記録用紙１−１を基準（２点）とし、良好なものほど点が増す５点法で評価付けをした。
【００７８】
評点
５；画像形成直後に、画像同士を擦り合わせても問題なし
４；画像形成直後に、画像面同士を重ねても問題なし
３；画像形成直後に、インクジェット記録用紙を重ね合わせても問題なし
２；画像形成直後に、インクジェット記録用紙を重ね合わせると問題あり
１；画像面の乾燥性悪く、明らかに実用上問題あるレベル
画質
上記インクジェット出力装置を用いて、１ｍｍ幅の中に細線を引いたチャート画面を描かせ、細線が明確に何本まで判別できるか、画像の滲みがないかで評価した。
【００７９】
インクジェット記録用紙１−１が基準（２点）となるよう、下記のごとき評点を定めた。
【００８０】
評点
５；１０本以上判別可能、滲みなし
４；９本程度判別可能、滲みほとんどなし
３；８本程度判別可能、滲みがあるがなんとか実用可能
２；６本程度判別可能、滲みあり
１；判別可能本数、滲み共に問題あり
結果を下記表１に示す。
【００８１】
【表１】

【００８２】
本発明内のインクジェット記録用紙１−３、１−４、１−５は、いずれの特性も良好である。これに対し、本発明外のインクジェット記録用紙１−１、１−２、１−６、１−７は少なくともいずれかの特性に問題があることがわかる。
【００８３】
【発明の効果】
本発明により、形成された画像の画質がよく、表面の乾燥性に優れ、しかもインク受容層のひび割れを生じないインクジェット記録材料とその製造方法を提供することができる。
【図面の簡単な説明】
【図１】インク受容層の製造装置の模式図である。
【符号の説明】
１　塗布液の貯留釜
２、４　パイプ
３　Ａ１の貯留釜
５、６　流量計
７　インラインミキサー
８　塗布装置[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ink jet recording material and a method for producing the same.
[0002]
[Prior art]
As a recording material used in the ink jet recording method, a porous paper made of a water-soluble binder such as polyvinyl alcohol to which an additive such as amorphous silica is added on a support called ordinary paper or an ink jet recording material There is known a recording material provided with an ink receiving layer.
[0003]
These recording materials are disclosed, for example, in JP-A Nos. 62-160277, 62-184879, 62-183382, and 64-11877.
[0004]
JP-B-3-56552, JP-A-10-81064, JP-A-10-119423, JP-A-10-175365, JP-A-10-203006, JP-A-10-217601, JP-A-11-20300, JP-A-11-20306 And JP-A-11-34481 disclose techniques for improving gloss and ink receptivity by using synthetic silica fine particles by a gas phase method.
[0005]
The recording material having such an ink receiving layer rapidly absorbs the hydrophilic ink for inkjet recording, and can seem to be dried instantaneously. Therefore, even immediately after image formation, the surface is not sticky, and the ink droplets ejected and landed do not bleed or expand around, and the image quality does not deteriorate.
[0006]
Forming an ink receiving layer having a void layer formed of inorganic fine particles on the substrate (support) as described above is one of effective means for improving the ink receiving property of the ink jet recording material. However, the amount of the inorganic binder used is limited so that the hydrophilic binder used in combination with the inorganic fine particles does not block the void layer and reduce the ink receptivity.
[0007]
As described above, the ink receiving layer coated and dried with the minimum necessary amount of the hydrophilic binder with respect to the inorganic fine particles in order to efficiently increase the void volume has a low film strength. In many cases, cracks occur, gloss is reduced, and image bleeding occurs, resulting in deterioration of image quality.
[0008]
Particularly when an ink receiving layer containing inorganic fine particles having an average particle diameter of 0.1 μm or less is provided, cracks are likely to occur, but it is known that a hydrophilic binder and a crosslinking agent thereof are used in combination to suppress the cracks. ing.
[0009]
Known crosslinking agents include, for example, epoxy compounds, aldehyde compounds, active halogen compounds, boric acid and its salts, borax, aluminum alum and the like.
[0010]
However, when a sufficient amount of the crosslinking agent is used to prevent the occurrence of cracks, the inconvenience that break phenomena newly occurs tends to occur. Breakage is a phenomenon in which, when handling a sheet-like recording material, when the recording material is bent, a crack occurs on the surface of the ink receiving layer. In particular, in applications where printing is performed by commercial inkjet plotters such as posters and in-store POPs, which are attracting attention in recent years, a large-sized sheet is easily broken due to handling of a large-sized sheet, which is a serious problem.
[0011]
Accordingly, there has been a demand for a technique for preventing the occurrence of cracks which does not use a large amount of the crosslinking agent as described above and which does not cause a problem such as a breakage phenomenon.
[0012]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to provide an ink jet recording material which has good image quality of a formed image, has excellent surface drying properties, and does not cause cracks in an ink receiving layer, and a method for producing the same.
[0013]
[Means for Solving the Problems]
As a result of intensive studies, the inventors of the present invention have found that the object of the present invention is achieved by adopting any of the following constitutions.
[0014]
[1] It contains at least a silanol-modified polyvinyl alcohol (A1), a non-silanol-modified polyvinyl alcohol (A2) having a degree of polymerization of 2,000 or more, and silica particles, and a mass ratio (A1 / A1 + A2) of A1 to A2 is 0.25. An ink jet recording material comprising a coating layer having a thickness of 0.75 to 0.75 on a substrate.
[0015]
[2] The method according to [1], wherein the degree of polymerization of the silanol-modified polyvinyl alcohol (A1) is 1,000 to 2,500, and the degree of polymerization of the non-silanol-modified polyvinyl alcohol (A2) is 2,500 to 6,000. Ink jet recording material.
[0016]
[3] The coating layer has a layer structure of two or more layers, and the layer closest to the substrate is at least a silanol-modified polyvinyl alcohol (A1) and a non-silanol-modified polyvinyl alcohol (A2) having a polymerization degree of 2,000 or more and silica. An ink jet recording material comprising particles and a coating layer having a mass ratio of A1 to A2 (A1 / A1 + A2) of 0.25 to 0.75 on a substrate.
[0017]
[4] The method for producing an inkjet recording material according to any one of [1] to [3], wherein the silanol-modified polyvinyl alcohol (A1) is added by an in-line mixer. .
[0018]
That is, according to the study of the present inventors, an inkjet recording material having an application layer (ink-receiving layer) using a binder obtained by appropriately mixing silanol-modified polyvinyl alcohol (A1) and ordinary polyvinyl alcohol (A2) has cracks. It was found that this was preferable in that it did not cause any problem.
[0019]
It is considered that the silanol-modified polyvinyl alcohol (A1) and the ordinary polyvinyl alcohol (A2) combine with each other to form large molecules by being connected to the silica particles, and exhibit preferable characteristics from the viewpoint of preventing cracking.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
[0021]
In the present invention, the coating liquid for the ink receiving layer (hereinafter referred to as a coating liquid) is composed of silica particles (fine particles of silica), a silanol-modified polyvinyl alcohol (A1) and a non-silanol-modified polyvinyl alcohol having a polymerization degree of 2,000 or more ( It contains at least the binder of A2) and its crosslinking agent. In addition, it is a general and preferable embodiment to contain an organic solvent, a cationic compound, a surfactant and the like.
[0022]
The silanol-modified polyvinyl alcohol (A1) is a compound having a structure represented by the following general formula (A1).
[0023]
Embedded image

[0024]
Actually, there is a commercially available product such as R1130 (manufactured by Kuraray). Incidentally, it is said that the polymerization degree of R1130 is 1700, n; about 99, m; 0 to 1, a silanol-modified polyvinyl alcohol (p is not 0).
[0025]
As the hydrophilic binder for the ink receiving layer, a binder having high transparency and high penetrability of the ink is preferably used. In that sense, in the present invention, as the hydrophilic binder, a silanol-modified polymer having a polymerization degree of 2,000 or more is used. Not used polyvinyl alcohol (A2) is used.
[0026]
Particularly preferred is a partially or completely saponified polymer having a degree of saponification of 80 or more, and polyvinyl alcohol having an average degree of polymerization of 2500 to 6000 is preferable. Examples of commercially available products include, in the following general formula (A2), n; 90, m; 10 and a degree of polymerization of 3,500, 4300 (all manufactured by Kuraray Co., Ltd., PVA235, 245).
[0027]
Embedded image

[0028]
It is preferable to use the above-mentioned hydrophilic binder such as polyvinyl alcohol at a small ratio with respect to the inorganic fine particles from the viewpoint of ink receptivity. However, if it is too small, cracks are easily generated.
[0029]
The greatest feature of the present invention is that cracking can be prevented even when the hydrophilic binder is used in a small ratio of 30% by mass or less based on the silica particles. Therefore, in the present invention, it is preferable to use the hydrophilic binder in an amount of 30% by mass or less, preferably 10 to 27% by mass, based on the silica particles.
[0030]
In a preferred embodiment of the present invention, 10 to 30 g / m ^{2 of} fumed silica as inorganic fine particles, 10 to 30% by mass of polyvinyl alcohol as binder for fumed silica, and boric acid or borate as a crosslinking agent are used. It is.
[0031]
In a preferred embodiment of the present invention, boric acid or borate is added in-line as described below immediately before coating. The boric acid added in-line may be a part of the total boric acid amount or the entire amount. The preferred amount of boric acid to be added varies depending on the particle size and amount of fumed silica and the amount of polyvinyl alcohol, but is suitably from 5 to 35% by mass based on polyvinyl alcohol. Preferably it is in the range of 8 to 30% by mass.
[0032]
The solution for in-line addition of boric acid is prepared by dissolving in a solvent mainly composed of water so that the concentration of boric acid becomes about 1 to 10% by mass. In the case of in-line addition, the flow rate is set according to the concentration, and the addition is performed in a predetermined amount of the coating solution controlled by a flow meter.
[0033]
Further, the ink receiving layer of the present invention preferably contains a cationic compound. Examples of the cationic compound include a cationic polymer and a water-soluble metal compound. Examples of the cationic polymer include polyethyleneimine, polydiallylamine, polyallylamine, polyalkylamine polymers, JP-A-63-280681, JP-A-1-40371, JP-A-6-234268, JP-A-7-125411, and Polymers having a primary to tertiary amino group and a quaternary ammonium group described in JP-A-193776 are preferably used. The molecular weight of these cationic polymers is preferably 5,000 or more, more preferably about 5,000 to 100,000.
[0034]
The amount of these cationic polymers used is 1 to 10% by mass, preferably 2 to 7% by mass, based on the silica particles.
[0035]
The coating liquid is usually prepared by dispersing silica particles in water using a high-pressure homogenizer, a high-speed homogenizer, a ball mill or the like, and mixing the dispersion with a hydrophilic binder, a crosslinking agent, a surfactant and the like. In order to increase the production efficiency, it is preferable to prepare a large amount of the coating solution at one time and to apply it continuously. Therefore, the amount of the coating liquid produced at one time is applied to the substrate over a long time. For example, it may exceed 5 hours, or even 10 hours. During the time from the preparation of the coating solution to the end of the coating, the coating solution is kept at a temperature of about 30 to 45 ° C. and aged.
[0036]
The coating liquid is usually manufactured in units of several hundred liters to several thousand liters per batch, and is temporarily stored in a storage tank (tank). It is supplied to a coating device through a liquid feed pipe and is coated on a support.
[0037]
Conventionally, all the components of the ink receiving layer were added during the production of the coating liquid, and were often supplied to the coating apparatus in the form of a complete coating liquid. However, in the present invention, it is preferable to prepare a coating solution without adding part or all of the silanol-modified polyvinyl alcohol (A1), and to add and mix a crosslinking agent into the coating solution immediately before applying the coating solution. .
[0038]
Specifically, part or all of A1 is added to and mixed with the coating liquid through a path in which the coating liquid is sent from the storage tank to the coating apparatus.
[0039]
This method is also called in-line addition, and a mixing device for that is also commercially available as an in-line mixer or a static mixer. For example, a static mixer manufactured by Kenics (USA), a static mixing element SMV type manufactured by Sulger (Switzerland), a Shimazaki pipe mixer manufactured by Koiritsu Kogyo, a Hi-Mixer manufactured by Toray, and a static mixer manufactured by Noritake. N10 and the like. Further, as the in-line dynamic mixer, those described in Japanese Patent Application No. 11-80655 can also be used.
[0040]
As a preferred embodiment of the present invention, the step of adding immediately before coating will be described in more detail with reference to the drawings.
[0041]
FIG. 1 is a schematic diagram of an apparatus for manufacturing an ink receiving layer. The coating liquid stored in the storage tank 1 is lowered through the pipe 2 using a head difference (a high-viscosity coating liquid can use a pump (not shown)). On the other hand, the solution containing A1 is stored in the storage tank 3 as an in-line addition liquid, and is similarly lowered through the pipe 4 using the head difference. The lowered coating liquid and A1 are controlled to a predetermined flow rate by the flow meters 5 and 6, respectively, and then mixed by the in-line mixer 7 to form a complete coating liquid, which is sent to the coating device 8 to be applied to the support. Applied.
[0042]
Next, the configuration of the ink receiving layer will be described. The ink receiving layer of the present invention mainly contains silica particles. Other inorganic fine particles such as calcium carbonate, magnesium carbonate, kaolin, clay, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, hydrotalcite, aluminum silicate, diatomaceous earth, calcium silicate, synthetic silica, and colloidal silica , Alumina, pseudo-boehmite and the like.
[0043]
Among the above silica particles, synthetic silica is preferable, and fumed silica is particularly preferably used. Synthetic silica includes those obtained by a wet method and those obtained by a gas phase method. Usually, silica fine particles often refer to wet process silica. Examples of the wet process silica include (1) silica sol obtained by double decomposition of sodium silicate with an acid or the like and an ion exchange resin layer, (2) colloidal silica obtained by heating and aging this silica sol, and (3) gelation of silica sol. By changing the formation conditions, silica gel in which primary particles of several microns to 10 microns have become siloxane-bonded three-dimensional secondary particles, and (4) silica sol, sodium silicate, sodium aluminate, etc. There are synthetic silicic acid compounds mainly composed of silicic acid such as those obtained by heat generation.
[0044]
In the present invention, the fumed silica preferably used is also called a dry method with respect to a wet method, and is generally produced by a flame hydrolysis method. Specifically, a method of making silicon tetrachloride by burning it with hydrogen and oxygen is generally known, but instead of silicon tetrachloride, silanes such as methyltrichlorosilane and trichlorosilane can be used alone or by silicon tetrachloride. And can be used in a mixed state. The fumed silica is commercially available as Aerosil (manufactured by Nippon Aerosil Co., Ltd.) and QS type (manufactured by Tokuyama Corporation) and can be easily obtained.
[0045]
The average particle size of the primary particles of the fumed silica used in the present invention is preferably 30 nm or less, and in order to obtain higher gloss, the average particle size is 3 to 10 nm and the specific surface area by the BET method is 250 m ² / g or more (preferably). Is preferably 250 to 500 m ² / g). The BET method referred to in the present invention is one of the methods for measuring the surface area of a powder by a gas phase adsorption method, and is a method for obtaining the total surface area of 1 g of a sample, that is, the specific surface area, from an adsorption isotherm.
[0046]
Usually, nitrogen gas is often used as the adsorption gas, and a method of measuring the amount of adsorption from the change in pressure or volume of the gas to be adsorbed is most often used. The most prominent expression of the isotherm for multimolecular adsorption is the Brunauer, Emmett, and Teller equation, which is called the BET equation and is widely used for determining the surface area. The amount of adsorption is determined based on the BET equation, and the surface area is obtained by multiplying the area occupied by one adsorbed molecule on the surface.
[0047]
The feature of the fumed silica is that the primary particles are present in a state of being secondary aggregated by being connected in a network structure or a chain shape, whereby high ink receptivity is obtained. The state of the secondary aggregation is preferably maintained at about 50 to 500 nm, whereby high ink receptivity can be obtained without reducing gloss.
[0048]
In the present invention, the amount of the silica particles to be contained in the ink receiving layer is preferably 8 g / ^{m 2} or more, the range of 10 to 30 g / ^{m 2} is more preferable.
[0049]
In the present invention, the ink receiving layer containing silica particles may be used in combination with another binder in order to maintain the properties as a film. As the binder, various known hydrophilic binders can be used. For example, gelatin and its derivatives, polyvinylpyrrolidone, pullulan, polyethylene glycol, carboxymethylcellulose, hydroxyethylcellulose, dextran, dextrin, polyacrylic acid and its salts, agar, carrageenan, xanthen gum, locust bean gum, alginic acid, gum arabic, water-soluble Examples thereof include polyvinyl butyral, and homo- or copolymers of a vinyl monomer having a carboxy group or a sulfonic acid group.
[0050]
The ink receiving layer in the present invention can contain various oil droplets in order to improve the brittleness of the film. Such oil droplets include hydrophobic high-boiling organic solvents having a solubility in water at room temperature of 0.01% by mass or less (eg, liquid paraffin, dioctyl phthalate, tricresyl phosphate, silicone oil, etc.) and polymer particles ( For example, particles obtained by polymerizing one or more polymerizable monomers such as styrene, butyl acrylate, divinylbenzene, butyl methacrylate, and hydroxyethyl methacrylate) can be contained. Such oil droplets can be preferably used in the range of 10 to 50% by mass based on the hydrophilic binder.
[0051]
In the present invention, a surfactant can be added to the ink receiving layer. The amount of the surfactant to be added is preferably 0.001 to 5 g, more preferably 0.01 to 3 g, per 100 g of a binder such as polyvinyl alcohol constituting the ink receiving layer.
[0052]
In the present invention, the ink receiving layer further contains a coloring dye, a coloring pigment, a fixing agent for the ink dye, an ultraviolet absorber, an antioxidant, a dispersant for the pigment, a defoaming agent, a leveling agent, a preservative, and a fluorescent whitening agent. Various known additives such as a viscosity stabilizer and a pH adjuster can also be added.
[0053]
In the present invention, the method for applying the ink receiving layer is not particularly limited, and a known coating method can be used. For example, there are a slide bead method, a curtain method, an extrusion method, an air knife method, a roll coating method, a ked bar coating method, and the like. Among the above coating methods, a slide bead method, a curtain method, and an extrusion method are particularly preferably used.
[0054]
In the present invention, the ink jet recording paper has a configuration in which at least one ink receiving layer is provided on a base material. However, a second ink receiving layer, an ink fixing layer, an intermediate layer, a protective layer, and the like may be further provided. Good.
[0055]
As the substrate (support) used in the present invention, a water-resistant support is preferably used. For example, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, diacetate resins, triacetate resins, acrylic resins, polycarbonate resins, and polystyrene resins Examples include resin films of vinyl chloride, polyimide resin, cellophane, celluloid, etc., supports coated (laminated) with paper with a polyolefin resin such as polyethylene or polypropylene, and glass plates.
[0056]
These supports may be transparent or opaque. The thickness of the water-resistant substrate used in the present invention is preferably about 50 to 200 μm.
[0057]
A particularly preferred substrate in the present invention is polyethylene terephthalate or polyolefin resin coated paper.
[0058]
Hereinafter, the polyolefin resin-coated paper will be described in detail.
The base paper constituting the polyolefin resin-coated paper is not particularly limited, and generally used paper can be used, but more preferably, smooth base paper used for a photographic support, for example, is preferable. As the pulp constituting the base paper, natural pulp, recycled pulp, synthetic pulp or the like may be used alone or in combination of two or more. The base paper contains additives generally used in papermaking, such as a sizing agent, a paper strength enhancer, a filler, an antistatic agent, a fluorescent whitening agent, and a dye.
[0059]
Further, a surface sizing agent, a surface strength agent, a fluorescent whitening agent, an antistatic agent, a dye, an anchoring agent and the like may be applied on the surface.
[0060]
The thickness of the base paper is not particularly limited, but preferably has good surface smoothness, such as applying a pressure by a calender or the like during papermaking or after papermaking, and has a basis weight of 30 to 250 g / g. m ² is preferred.
[0061]
As the resin of the resin-coated paper, a polyolefin resin or a resin that is cured by an electron beam can be used. The polyolefin resin is a low-density polyethylene, high-density polyethylene, polypropylene, polybutene, a homopolymer of an olefin such as polypentene or a copolymer of two or more olefins such as an ethylene-propylene copolymer and a mixture thereof, Those having various densities and melt viscosity indices (melt index) can be used alone or in combination.
[0062]
Also, in the resin of the resin-coated paper, white pigments such as titanium oxide, zinc oxide, talc, and calcium carbonate, fatty acid amides such as stearic acid amide and arachidic amide, zinc stearate, calcium stearate, aluminum stearate, and stearin Fatty acid metal salts such as magnesium acid, antioxidants such as Irganox 1010 and Irganox 1076, blue pigments and dyes such as cobalt blue, ultramarine blue, cecilian blue, phthalocyanine blue, and magenta such as cobalt violet, fast violet, and manganese purple It is preferable to add various additives such as pigments and dyes, fluorescent brighteners and ultraviolet absorbers in an appropriate combination.
[0063]
In the case of a polyolefin resin on a running base paper, the resin-coated paper that is preferably used in the present invention is manufactured by a so-called extrusion coating method of casting a resin melted by heating, and both surfaces thereof are coated with the resin. You. In the case of a resin which is cured by an electron beam, the resin is applied by a commonly used coater such as a gravure coater or a blade coater, and then irradiated with an electron beam to cure and coat the resin. Further, it is preferable to perform an activation treatment such as a corona discharge treatment or a flame treatment on the base paper before coating the resin on the base paper. The surface (surface) of the support on which the ink receiving layer is applied has a glossy surface, a matte surface, and the like, depending on the application, and the glossy surface is used particularly advantageously. It is not necessary to coat the back surface with a resin, but it is preferable to coat the resin from the viewpoint of curling prevention. The back surface is usually a matte surface, and the front surface or both front and back surfaces can be subjected to an activation treatment such as a corona discharge treatment or a flame treatment as required. The thickness of the resin coating layer is not particularly limited, but is generally 5 to 50 μm thick on the surface or on both sides.
[0064]
In the present invention, various back coat layers can be applied to the substrate for antistatic properties, transport properties, curling prevention properties, and the like. The back coat layer can contain an inorganic antistatic agent, an organic antistatic agent, a hydrophilic binder, a latex, a curing agent, a pigment, a surfactant and the like in an appropriate combination.
[0065]
【Example】
Next, the configuration and effects of the present invention will be more specifically shown as examples, but of course, embodiments of the present invention are not limited to the following.
[0066]
In the description, “parts” means “parts by mass”.
[Example 1]
Inkjet recording paper 1-1 (outside the present invention)
As a base material, a resin composition composed of low-density polyethylene (70 parts), high-density polyethylene (20 parts) and titanium oxide (10 parts) was applied to a surface of 120 g / m ² paper made of pulp at 25 g / m ^2. A resin-coated paper obtained by applying a resin composition comprising high-density polyethylene (50 parts) and low-density polyethylene (50 parts) to the back surface at 25 g / m ² was used.
[0067]
The coating solution for the ink receiving layer shown below was prepared so that the fumed silica had a solid content of 8% by mass. After the coating solution was aged at 38 ° C. for 3 hours, the flow rate was set to 238 g / m ² on the base material using a slide bead coating device, and the coating solution was dried. This is designated as inkjet recording paper 1-1.
[0068]
<Ink receiving layer coating liquid 1-1>
100 parts of fumed silica (average primary particle diameter 7 nm, specific surface area 300 m ² / g by BET method)
2 parts of dimethyldiallylammonium chloride homopolymer (Shalol DC902P, molecular weight 9000; manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
3 parts of basic polyaluminum hydroxide (Purachem WT; manufactured by Riken Green)
Boric acid 8 parts Polyvinyl alcohol 25 parts (Saponification degree 88%, average polymerization degree 3500)
Surfactant 0.3 part inkjet recording paper 1-2 (outside the present invention)
The ink receiving layer coating liquid 1-1 was prepared in the same manner as the ink receiving layer coating liquid 1-1 except that polyvinyl alcohol was changed to 20 parts and silanol-modified polyvinyl alcohol (R1130, average polymerization degree: 1700; manufactured by Kuraray Co., Ltd.) was added instead. In the same manner as in the above, inkjet recording paper 1-2 was produced.
[0069]
Inkjet recording paper 1-3 (within the present invention)
The ink receiving layer coating liquid 1-1 was prepared in the same manner as the ink receiving layer coating liquid 1-1 except that the polyvinyl alcohol was changed to 18 parts, and instead of silanol-modified polyvinyl alcohol (R1130, average polymerization degree: 1700; manufactured by Kuraray Co., Ltd.), 7 parts. In the same manner as in the above, inkjet recording paper 1-3 was produced.
[0070]
Inkjet recording paper 1-4 (within the present invention)
The ink receiving layer coating liquid 1-1 was changed to 12.5 parts of polyvinyl alcohol, and 12.5 parts of silanol-modified polyvinyl alcohol (R1130 average polymerization degree: 1700; manufactured by Kuraray Co.) was added instead. Inkjet recording paper 1-4 was prepared in the same manner as in liquid 1-1.
[0071]
Inkjet recording paper 1-5 (within the present invention)
The ink receiving layer coating liquid 1-1 was prepared in the same manner as the ink receiving layer coating liquid 1-1 except that 7 parts of polyvinyl alcohol was used and 18 parts of silanol-modified polyvinyl alcohol (R1130, average polymerization degree 1700; manufactured by Kuraray Co., Ltd.) was added instead. In the same manner as in the above, inkjet recording paper 1-5 was produced.
[0072]
Inkjet recording paper 1-6 (outside the present invention)
The ink receiving layer coating liquid 1-1 was prepared in the same manner as in the ink receiving layer coating liquid 1-1 except that polyvinyl alcohol was changed to 5 parts and silanol-modified polyvinyl alcohol (R1130, average polymerization degree: 1700; manufactured by Kuraray Co., Ltd.) was added instead. In the same manner as in the above, inkjet recording paper 1-6 was produced.
[0073]
Inkjet recording paper 1-7 (outside the present invention)
The ink receiving layer coating liquid 1-1 was prepared in the same manner as the ink receiving layer coating liquid 1-1 except that 25 parts of silanol-modified polyvinyl alcohol (R1130, average polymerization degree: 1700; manufactured by Kuraray Co., Ltd.) was added instead of the polyvinyl alcohol of the ink receiving layer coating liquid 1-1. In the same manner as in the above, inkjet recording paper 1-7 was produced.
[0074]
Evaluation of Characteristics The surface of the ink jet recording paper 1-1 to 7 having the ink receiving layer after coating and drying the cracked ink receiving layer was carefully observed with the naked eye to evaluate the state of the crack.
[0075]
Ink-jet recording paper 1-1 to which silanol-modified polyvinyl alcohol was not added was used as a reference (two points), and evaluation was made according to a five-point method in which the better the point, the more points increased.
[0076]
Rating 5: Not recognized at all 4; Almost none 3; Recognized but manageable level 2; Recognizable 1; Level with apparently practical problem Figure in JP-A-2001-277483 having a surface-drying film cassette Using the ink jet output device described in No. 1, the drying property was observed while printing the entire surface with black ink.
[0077]
The ink-jet recording paper 1-1 was used as a reference (two points), and the evaluation was made according to a five-point method in which the better the point, the more points increased.
[0078]
Rating 5: There is no problem if the images are rubbed together immediately after image formation. 4; There is no problem if the image surfaces are overlapped immediately after image formation. 3; There is no problem if ink jet recording paper is superimposed immediately after image formation. 2: There is a problem when ink-jet recording papers are superimposed immediately after image formation. 1; Level of image quality is poor and obviously problematic in practical use. A chart screen was drawn, and the number of fine lines that could be clearly identified was evaluated based on whether there was no blurring of the image.
[0079]
The following scores were determined so that the ink jet recording paper 1-1 was used as a reference (two points).
[0080]
Rating 5: 10 or more discrimination possible, no bleeding 4; about 9 discrimination possible, almost no bleeding 3; about 8 discrimination possible, bleeding but somehow practical 2; about 6 discrimination, bleeding 1; There is a problem in both the number of lines and bleeding. The results are shown in Table 1 below.
[0081]
[Table 1]

[0082]
The ink jet recording papers 1-3, 1-4, and 1-5 in the present invention have good properties. On the other hand, it can be seen that the inkjet recording papers 1-1, 1-2, 1-6, and 1-7 outside the present invention have a problem in at least one of the characteristics.
[0083]
【The invention's effect】
According to the present invention, it is possible to provide an ink jet recording material having good image quality of a formed image, excellent surface drying properties, and not causing cracks in an ink receiving layer, and a method for producing the same.
[Brief description of the drawings]
FIG. 1 is a schematic view of an apparatus for manufacturing an ink receiving layer.
[Explanation of symbols]
1 Reservoir 2 for coating liquid, 4 Reservoir 5 for pipe 3 A1 Flow meter 7 In-line mixer 8 Coating device

Claims (4)

It contains at least a silanol-modified polyvinyl alcohol (A1), a non-silanol-modified polyvinyl alcohol (A2) having a polymerization degree of 2,000 or more, and silica particles, and a mass ratio (A1 / A1 + A2) of A1 to A2 of 0.25 to 0.2. An ink jet recording material having a coating layer of 75 on a substrate. 2. The ink jet recording material according to claim 1, wherein the degree of polymerization of the silanol-modified polyvinyl alcohol (A1) is 1000 to 2500, and the degree of polymerization of the non-silanol-modified polyvinyl alcohol (A2) is 2500 to 6000. . The coating layer has a layer structure of two or more layers, and the layer closest to the base material contains at least silanol-modified polyvinyl alcohol (A1), a non-silanol-modified polyvinyl alcohol (A2) having a polymerization degree of 2,000 or more, and silica particles. An ink jet recording material having a coating layer having a mass ratio (A1 / A1 + A2) of A1 to A2 of 0.25 to 0.75 on a substrate. The method for producing an ink jet recording material according to any one of claims 1 to 3, wherein the silanol-modified polyvinyl alcohol (A1) is added using an inline mixer.

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