JP3868587B2 - Thermal transfer sheet and manufacturing method thereof - Google Patents

Description

【００１５】
また、耐熱滑性層に含有する耐熱樹脂は、イソシアネート基と反応する官能基をもたないもので、詳しくは樹脂の水酸基、アミノ基、カルボキシル基、メルカプト基等のイソシアネートと反応をする官能基を有していないもので、かつシリルイソシアネートと相溶性のある樹脂である。特にノルボルネン樹脂が上記の性能を充分に満たすため好ましく使用される。耐熱滑性層用塗工液のシリルイソシアネートと、イソシアネート基との反応性基をもたず、かつ該シリルイソシアネートと相溶性のある耐熱性樹脂との配合は、シリルイソシアネート１００重量部に対して、その耐熱樹脂が５〜２０００重量部の範囲で使用でき、耐熱樹脂が１０〜１０００重量部の範囲が特に好ましく使用できる。耐熱樹脂の量が少ないと、耐熱滑性層の塗工安定性に欠ける点が出てきて、耐熱滑性層の印刷面にムラが生じやすくなる。一方、耐熱樹脂の量が多くなるとサーマルヘッドとの滑り性が低下し、サーマルヘッドと熱転写シートとの熱融着が生じやすくなり、好ましくない。
【００１６】
耐熱滑性層用塗工液はシリルイソシアネートと、イソシアネート基との反応性基をもたず、かつ該シリルイソシアネートと相溶性のある耐熱性樹脂を含有しているため、さらにシリルイソシアネートは塗工液の状態で希釈されていれば、自己架橋を抑えられるため、耐熱滑性層の塗工液がゲル化することなく、安定したものとなり、耐熱滑性層の印刷面が均一で、ムラのない仕上がりが得られる。耐熱滑性層用塗工液は、上記一般式で表されるシリルイソシアネートを主体とし、フィラーや滑剤を、そのシリルイソシアネートと反応硬化するものでなければ、本発明の目的を妨げない範囲で、添加してもよい。
【００１７】
その適当なフィラーとしては、例えば、タルク、カオリン、クレー、炭酸カルシウム、水酸化マグネシウム、炭酸マグネシウム、酸化マグネシウム、沈降性硫酸バリウム、ハイドロタルサイトシリカ等の無機フィラーと、アクリル樹脂、ベンゾグアナミン樹脂、シリコーンやテフロン等からなる有機フィラーが挙げられるが、好ましくは、タルク、カオリン、クレー等のへきかい性を有し、かつ硬度は比較的低いがサーマルヘッドのクリーニング性を有するものが良い。
具体的にはタルクの場合、散弾式磨耗度で１５〜２００ｍｇのものが好ましく、磨耗度が低いとヘッド滓を生じやすく、また高いとサーマルヘッド保護層の磨耗が著しくなる。
【００１８】
更に性能向上及び性能安定化の為に、耐熱滑性層に滑剤を添加することが好ましく、これらの添加する滑剤としては、ポリエチレンワックス、パラフィンワックス等のワックス類、高級脂肪族アルコール、オルガノポリシロキサン、アニオン系界面活性剤、カチオン系界面活性剤、両性界面活性剤、ノニオン系界面活性剤、フッ素系界面活性剤、有機カルボン酸及びその誘導体、長鎖脂肪族化合物等が挙げられる。特に、リン酸エステル系界面活性剤等の滑剤を用いることが好ましい。それは、高エネルギー印加時に熱離型剤として補足的に作用するためである。
【００１９】
前記の一般式で表されるシリルイソシアネートと、必要に応じて添加剤を加え、塗工適性に合うように選択したアセトン、酢酸エチル、メチルエチルケトン、トルエン、キシレン等の溶剤に溶解、或いは分散させて塗工液を作成し、この塗工液をグラビアコーター、ロールコーター、ワイヤバー等の慣用の塗工手段で塗布、乾燥して、滑性層を形成することができる。
滑性層の塗工量は、固形分基準で５．０ｇ／ｍ² 以下がよく、好ましくは０．１〜２．０ｇ／ｍ² の厚さで充分な性能を持つ耐熱滑性層を形成することが出来る。
尚、フィラーや滑剤の添加剤の添加量は、耐熱滑性層を形成するバインダー樹脂１００重量部あたり１〜１５０重量部であり、好ましくは、４０〜１２０重量部である。
【００２０】
本発明では、上記基材フィルムと耐熱滑性層との間に、プライマー層を設け、基材フィルムと耐熱滑性層の接着性を向上させることができる。
プライマー層は、基材フィルムと耐熱滑性層に対し、充分な接着性を有するとともに、基材フィルムの熱変形を抑えるような耐熱性、寸法安定性を有していることが好ましい。このプライマー層は、熱可塑性樹脂、各種熱硬化性樹脂、各種硬化剤と反応基を有する樹脂との混合組成、光及び電離放射線にて架橋反応を生じる塗膜組成物のいずれでもよく、塗工量については固形分基準で１．０ｇ／ｍ² 以下、好ましくは０．０１〜０．０５ｇ／ｍ² の厚さが良い。
尚、基材フィルムと耐熱滑性層の接着性を向上させるために、基材フィルムの表面に易接着処理やコロナ放電処理を行い、プライマー層を設けないことも可能である。
【００２１】
（熱転写色材層）
上記基材フィルムの他の面に形成する熱転写色材層としては、昇華型熱転写シートの場合には昇華性の染料を含む層、すなわち熱昇華性の染料層を形成し、一方、熱溶融型の熱転写シートの場合には顔料等で着色した熱溶融性インキ層を形成する。
以下昇華型熱転写シートの場合を代表例として説明するが、本発明は昇華型熱転写シートのみに限定されるものではない。昇華型の熱転写色材層に用いられる染料としては、従来、公知の熱転写用シートに使用されている染料はいずれも本発明に使用可能であり特に限定されない。例えば、いくつかの好ましい染料としては、赤色染料として、ＭＳ ＲＥＤ Ｇ、Ｍａｃｒｏ Ｒｅｄ Ｖｉｏｒｅｔ
【００２２】
Ｒ、Ｃｅｒｅｓ Ｒｅｄ ７Ｂ、Ｓａｍａｒｏｎ Ｒｅｄ ＨＢＳＬ、Ｒｅｓｏｌｉｎ Ｒｅｄ Ｆ３ＢＳ等が挙げられ、又、黄色の染料としては、ホロンブリリアントイエロー６ＧＬ、ＰＴＹ−５２、マクロレックスイエロー６Ｇ等が挙げられ、又、青色染料としては、カヤセットブルー７１４、ワクソリンブルーＡＰ−ＦＷ、ホロンブリリアントブルー−Ｓ−Ｒ、ＭＳブルー１００等が挙げられる。
【００２３】
上記のごとき染料を担持する為のバインダー樹脂として好ましいものを例示すれば、エチルセルロース、ヒドロキシエチルセルロース、エチルヒドロキシセルロース、ヒドロキシプロピルセルロース、メチルセルロース、酢酸セルロース、酢酪酸セルロース等のセルロース系樹脂、ポリビニルアルコール、ポリ酢酸ビニル、ポリビニルブチラール、ポリビニルアセトアセタール、ポリビニルピロリドン等のビニル系樹脂、ポリ（メタ）アクリレート、ポリ（メタ）アクリルアミド等のアクリル樹脂、ポリウレタン系樹脂、ポリアミド系樹脂、ポリエステル系樹脂等が挙げられるが、これらの中では、セルロース系、ビニル系、アクリル系、ウレタン系及びポリエステル系等の樹脂が耐熱性、染料の移行性等の点から好ましい。
【００２４】
染料層は、前記の基材フィルムの一方の面に、以上の如き染料及びバインダーに必要に応じて添加剤、例えば、離型剤や無機の微粒子などを加えたものを、トルエン、エチルエチルケトン、エタノール、イソプロピルアルコール、シクロヘキサノン、ＤＭＦ等の適当な有機溶剤に溶解したり、或いは有機溶剤や水に分散した分散体を、例えば、グラビア印刷法、スクリーン印刷法、グラビア版を用いたリバースロールコーティング印刷法等の手段により塗布及び乾燥して形成することが出来る。
【００２５】
このようにして形成する染料層は０．２〜５．０μｍ、好ましくは０．４〜２．０μｍ程度の厚さであり、又、染料層中の昇華性染料は、染料層の重量の５〜９０重量％、好ましくは１０〜７０重量％の量で存在するのが好適である。
形成する染料層は所望の画像がモノカラーである場合には、前記染料のうちから１色を選んで形成し、又、所望の画像がフルカラー画像である場合には、例えば、適当なシアン、マゼンタ及びイエロー（更に必要に応じてブラック）を選択して、イエロー、マゼンタ及びシアン（更に必要に応じてブラック）の染料層を形成する。
【００２６】
（熱転写シートの製造方法）
本発明の熱転写シートの製造方法は、基材フィルムの一方の面に熱転写色材層を有し、他方の面に耐熱滑性層を設ける熱転写シートの製造方法において、該耐熱滑性層がシリルイソシアネートと、イソシアネート基との反応性基をもたず、かつ該シリルイソシアネートと相溶性のある耐熱性樹脂を含有する塗工液により、該基材フィルムに該耐熱滑性層を塗工し、乾燥して形成する時に、溶媒が蒸発し、シリルイソシアネート自体が自己架橋の反応が終了することを特徴とする。
【００２７】
熱転写シートは、基材フィルムの一方の面に熱転写色材層を有し、他方の面に耐熱滑性層を設けた構成で、該耐熱滑性層を形成するための塗工液にシリルイソシアネートと、イソシアネート基との反応性基をもたず、かつ該シリルイソシアネートと相溶性のある耐熱性樹脂を有している。耐熱滑性層の塗工液中ではシリルイソシアネートは希釈されていて安定であるが、塗工された後、溶媒が蒸発して、シリルイソシアネートが自己架橋する反応が行われる、その塗工、乾燥時に自己架橋の反応が終了する。したがって、耐熱滑性層の塗工後において、エージング（加熱熟成）等の熱処理や、紫外線照射や電子線照射等の装置を必要としない。一方、熱転写シートの耐熱滑性層のより耐熱性向上のために、各種イソシアネート硬化剤や不飽和結合を有するモノマー、オリゴマーとの反応生成物を使用することができる。そして、硬化手段は加熱、電離放射線の照射等あげられるが、加熱の場合では、塗工液中に硬化前の未反応の材料を混合させておくため、塗工液の貯蔵安定性から硬化速度を遅めにすることが行われる。このようなときには、上記の製造方法で、耐熱滑性層を塗工し、乾燥した後に、熱転写シートを加熱熟成して、耐熱滑性層の硬化処理を行うこともできる。
【００２８】
上記の如き熱転写シートを用いて、画像を形成するために使用する、被転写材である受像シートは、その記録面が前記の染料に対して染料受容性を有するものであればいかなるものでもよく、又、染料受容性を有しない紙、金属、ガラス、合成樹脂などである場合には、その少なくとも一方の表面に染料受容層を形成すればよい。又、熱溶融型の熱転写シートの場合には、被転写材は特に限定されず、通常の紙やプラスチックフィルムであってもよい。
上記の熱転写シート及び上記の如きシートを使用して熱転写を行う際に使用するプリンターとしては、公知の熱転写プリンターがそのまま使用可能であり、特に限定されない。
【００２９】
【実施例】
次に参考例、実施例及び比較例を挙げて本発明を更に具体的に説明する。尚、文中、部又は％とあるのは特に断りの無い限り重量基準である。
（実施例１）
基材フィルムとして６μｍ厚のポリエチレンテレフタレートフィルムに下記組成の耐熱滑性層用塗工液Ａを乾燥時約０．５ｇ／ｍ² になるように塗布及び温度１００℃の熱風を当て乾燥した。
基材フィルムの他方の面に、下記組成の熱転写色材層用塗工液Ａを乾燥時約１．０ｇ／ｍ² になるように塗布及び乾燥して、熱転写色材層を形成し、本発明の実施例１の熱転写シートを作製した。
【００３０】
耐熱滑性層用塗工液Ａ組成
シリルイソシアネート １０部
（株式会社マツモト交商製、オルガチックスＳＩＣ−４３４）
ノルボルネン樹脂 ５部
（日本合成ゴム株式会社製、アートンＧ）
メチルエチルケトン ５部
トルエン ５部
【００３１】
熱転写色材層用塗工液Ａ組成
ＭＳ−ＲＥＤ−Ｇ ２．００部
（三井東圧化学株式会社製、ディスパースレッド６０）
マクロレックスレッドバイオレットＲ １．５０部
（バイエル社製、ディスパースバイオレット２６）
ポリビニルアセトアセタール樹脂 ３．５０部
（積水化学工業株式会社製、エスレックスＫＳ−５）
メチルエチルケトン ４６．５０部
トルエン ４６．５０部
【００３２】
（実施例２）
実施例１の耐熱滑性層塗工液Ａに代えて下記の塗工液Ｂを用い、その他は実施例１と同様にして実施例２の熱転写シートを得た。
耐熱滑性層用塗工液Ｂ組成
シリルイソシアネート １０部
（株式会社マツモト交商製、オルガチックスＳＩＣ−４３４）
ノルボルネン樹脂 １０部
（日本合成ゴム株式会社製、アートンＧ）
メチルエチルケトン ５部
トルエン ５部
【００３３】
（実施例３）
実施例１の耐熱滑性層塗工液Ａに代えて下記の塗工液Ｃを用いた以外は、実施例１と同様にして実施例３の熱転写シートを得た。
耐熱滑性層用塗工液Ｃ組成
シリルイソシアネート １０部
（株式会社マツモト交商製、オルガチックスＳＩＣ−４３４）
ポリカーボネート樹脂 １０部
（帝人化成株式会社製、パンライトＫ−１３００）
メチルエチルケトン ５部
トルエン ５部
【００３４】
（実施例４）
実施例１の滑性層塗工液Ａに代えて下記の塗工液Ｄを用いた以外は、実施例１と同様にして実施例４の熱転写シートを得た。
耐熱滑性層用塗工液Ｄ組成
シリルイソシアネート １部
（株式会社マツモト交商製、オルガチックスＳＩＣ−４３４）
ノルボルネン樹脂 ２０部
（日本合成ゴム株式会社製、アートンＧ）
メチルエチルケトン ５部
トルエン ５部
【００３５】
（比較例１）
実施例１の滑性層塗工液Ａに代えて下記の塗工液Ｅを用いた以外は、実施例１と同様にして比較例１の熱転写シートを得た。
耐熱滑性層用塗工液Ｅ組成
シリルイソシアネート １０部
（株式会社マツモト交商製、オルガチックスＳＩＣ−４３４）
メチルエチルケトン ５部
トルエン ５部
【００３６】
（比較例２）
基材フィルムとして６μｍ厚のポリエチレンテレフタレートフィルムに下記の耐熱滑性層用塗工液Ｆを乾燥時約１．０ｇ／ｍ² になるように塗布及び乾燥した。さらに、６０℃で７日間の加熱熟成をして硬化処理を行い、耐熱滑性層を形成した。基材フィルムの他方の面に、前記の熱転写色材層用塗工液Ａを乾燥時約１．０ｇ／ｍ² になるように塗布及び乾燥して、熱転写色材層を形成し、比較例２の熱転写シートを作製した。
耐熱滑性層用塗工液Ｅ組成
ポリビニルブチラール樹脂 １．６０部
（積水化学工業株式会社製、エスレックＢＸ−１）
ポリイソシアネート ４．２３部
（大日本インキ化学工業株式会社製、バーノックＤ−７５０−４５）
リン酸エステル系界面活性剤 ０．６８部
（第一工業製薬株式会社製、プライサーフＡ２０８Ｓ）
タルク（日本タルク製、ミクロエースＬ−１） ０．３２部
メチルエチルケトン ３８．４３部
トルエン ３８．４３部
【００３７】
（評価方法１）
上記の各熱転写シートにおいて、耐熱滑性層を形成した後に巻き取って２０℃の室内で３日間放置する。（但し、比較例２は、加熱熟成を行って、その後に上記条件の室内放置を行う。）
その放置後、各熱転写シートの他方の面に熱転写色材層の塗工液を塗布、乾燥して熱転写色材層を形成した。そして、その熱転写色材層の塗工された面の状態を目視にて観察し、評価する。判断基準は以下の通りである。
○：塗工ムラがなく、均一な塗工面である。
×：塗工ムラがある。
【００３８】
（評価方法２）
上記の熱転写シートを従来より使用されている受像シートと重ね、詳細には図１に示すように、熱転写シート３の熱転写色材層と受像シート４の受像面とを重ね、サーマルヘッド２とプラテンロール５との間にはさみ、サーマルヘッド２の上から２０００ｇの荷重（重り）１をかける。次に受像シート４を固定し、熱転写シート３をテンシロン（ＯＲＩＥＮＴＥＣ製、ＶＣＴ−１０００）で矢印方向に（上記の荷重方向と直交し、サーマルヘッドに対し、印字する搬送方向に）一定速度（５００ｍｍ／ｍｉｎ）で引っ張る。その際に、サーマルヘッド２は以下の条件で通電しておき、熱転写シート３とサーマルヘッド２との熱融着の有無を目視にて観察し、評価する。
【００３９】
＜通電時の印画条件＞
電圧 ：１８Ｖ
パルス幅：１１．２５ｍｓ
記録周期：２２．５ｍｓ／ｌｉｎｅ
【００４０】
上記熱融着の評価の判断基準は以下の通りである。
○：熱融着が認められない。
△：熱融着が少し認められる。
×：熱融着が認められ、熱転写シートに破れが生じる。
【００４１】
（評価方法３）
上記の熱転写シートを３ｃｍ四方に切断し、専用の試料ホルダーに挟み、赤外分光光度計（日本分光工業製、Ａ−１００）で赤外線吸収波長を測定する。２３００ｃｍ^-1付近の波長の吸収の有無で、未反応のイソシアネート基の有無を確認する。尚、各熱転写シートは耐熱滑性層の塗布、乾燥直後の状態で赤外線吸収波長を測定する。比較例２の熱転写シートは、耐熱滑性層の塗布、乾燥直後で、加熱熟成前の状態で測定する。
【００４２】
（評価結果）
評価結果を表１に示す。
（以下余白）
【表１】

【００４３】
【発明の効果】
以上のごとき本発明によれば、基材フィルムの一方の面に熱転写色材層を有し、他方の面に耐熱滑性層を設けた熱転写シートにおいて、該耐熱滑性層を形成するための塗工液にシリルイソシアネートと、イソシアネート基との反応性基をもたず、かつ該シリルイソシアネートと相溶性のある耐熱性樹脂を含有し、該基材フィルムに該耐熱滑性層を耐熱滑性層用塗工液により塗工し、乾燥して形成する時に、溶媒が蒸発し、シリルイソシアネート自体が自己架橋の反応が終了する。したがって、サーマルヘッドとの滑り性が良く、サーマルヘッドと熱転写シートとの熱融着が生じたりせず、耐熱滑性層と合い重なる面への滑性剤の裏移りがなく、更に耐熱滑性層の印刷面が均一で、ムラのない、耐熱性に優れた熱転写シートが得られ、さらに、耐熱滑性層はシリルイソシアネートが塗工液の状態で希釈されていれば、自己架橋を抑えられるため、耐熱滑性層の塗工液がゲル化することなく、安定したものとなり、耐熱滑性層の印刷面が均一で、ムラのない仕上がりが得られ、熱転写画像の品質向上につながる。また、耐熱滑性層のシリルイソシアネートは、塗工し、乾燥する時に、自己架橋して、その反応が終了するので、耐熱滑性層の塗工後において、エージング（加熱熟成）等の熱処理や、紫外線照射や電子線照射等の装置を必要としない。
【図面の簡単な説明】
【図１】熱転写シートと受像シートを重ね、サーマルヘッドで通電加熱中の熱転写シートとサーマルヘッドとの熱融着の有無を評価する時の状態を示す説明図である。
【符号の説明】
１ ２０００ｇの重り
２ サーマルヘッド
３ 熱転写シート
４ 受像シート
５ プラテンロール[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thermal transfer sheet. More specifically, a heat-resistant slipping layer is provided on a base film, and is excellent in heat responsiveness such as slidability and releasability with a thermal head, and between the thermal head and the thermal transfer sheet. The present invention relates to a thermal transfer sheet that does not cause thermal fusion and further prevents the slipping agent from being transferred to the surface that overlaps the slipping layer, and a method for manufacturing the same.
[0002]
[Prior art]
Conventionally, as a thermal transfer sheet, a plastic film such as a polyester film is used as a base film, and a sublimation type thermal transfer sheet in which a dye layer composed of a sublimable dye and a binder resin is provided on one surface of the base film; There is known a heat-melting type thermal transfer sheet provided with an ink layer made of a heat-meltable composition containing a colorant instead of a dye layer. These thermal transfer sheets are heated in the form of an image from the back by a thermal head, and the dye or ink layer of the dye layer is transferred to a transfer material to form an image.
[0003]
Furthermore, in the conventional thermal transfer sheet, if high energy is applied to the thermal transfer sheet when printing a high density image, the substrate film is fused by heat with the thermal head, and a paper jam (jam) occurs in the thermal transfer printer. Sometimes.
For this reason, it has been proposed to apply various lubricants on the film on the side opposite to the dye layer or the ink layer for the purpose of providing the thermal transfer sheet with a slip property.
[0004]
[Problems to be solved by the invention]
In order to provide slipperiness on the film on the opposite side of the dye layer or ink layer of the thermal transfer sheet, the above-mentioned base film is fused with the thermal head by heat and the paper clogging occurs in the thermal transfer printer. A slipping layer of resin containing groups was provided. However, when the silyl group is in a free state, it shifts to the printing surface of the dye layer or ink layer, and there is a problem that coating unevenness when the dye layer or ink layer is provided, so-called repellency occurs.
In addition, a method of using highly reactive silyl isocyanate to eliminate a free silyl group has been reported. Since this silyl isocyanate has high reactivity, the reaction is completed during drying after coating, so that the unreacted silyl group was transferred to the printing surface of the dye layer or ink layer. However, since silyl isocyanate alone has low film-forming properties, unevenness may occur on the printed surface, and heat resistance is not sufficient, and further heat resistance is required.
[0005]
Accordingly, an object of the present invention is to provide a thermal transfer sheet having a thermal transfer color material layer on one side of a base film and a heat-resistant slipping layer on the other side, which is excellent in slidability with the thermal head. Heat transfer sheet and heat transfer sheet does not occur, there is no slip-off of the lubricant on the surface that overlaps the slipping layer, and the printed surface of the slipping layer is uniform, uniform, and heat resistant An object is to provide an excellent thermal transfer sheet and a method for producing the same.
[0006]
[Means for Solving the Problems]
  The above object is achieved by the present invention described below. That is, the thermal transfer sheet of the present invention is a thermal transfer sheet having a thermal transfer color material layer on one surface of a base film and a heat-resistant slip layer provided on the other surface.In coating liquid to formIt is characterized by having a heat-resistant resin that does not have a reactive group of silyl isocyanate and an isocyanate group and is compatible with the silyl isocyanate. The thermal transfer color material layer is a heat sublimable dye layer or a heat-meltable ink layer.
[0007]
  Further, in the method for producing a thermal transfer sheet having a thermal transfer color material layer on one surface of a base film and a heat-resistant slipping layer on the other surface, the heat-resistant slipping layer reacts with silyl isocyanate and an isocyanate group. Contains a heat-resistant resin that has no functional group and is compatible with the silyl isocyanateDepending on the coating liquidApply the heat-resistant slip layer to the base film and dryFormedIn this case, the solvent is evaporated, and the silyl isocyanate itself is characterized in that the self-crosslinking reaction is completed.
[0008]
[Action]
  Good sliding performance with thermal head, no thermal fusion between thermal head and thermal transfer sheet,Heat resistanceThere is no slip-off of the lubricant to the surface that overlaps with the slipping layer, andHeat resistanceIn order to obtain a thermal transfer sheet having a uniform printing surface of the slippery layer, no unevenness and excellent heat resistance, the present invention has a thermal transfer color material layer on one side of the base film and the other side. In the thermal transfer sheet provided with a heat resistant slipping layer, theHeat resistanceSlippery layerIn coating liquid to formIt has a heat-resistant resin that does not have a reactive group of silyl isocyanate and an isocyanate group and is compatible with the silyl isocyanate. That is, by providing a heat-resistant slipping layer on one surface of the base film, the heat resistance and slipping functions can be exhibited by one layer.
[0009]
  Lubricants such as surfactants that have lubricity and heat release properties, and lubricants that are liquid at room temperature, such as oil, have good responsiveness to instantaneous heating and are used because there is little difference in sliding characteristics between printing and non-printing. In many cases, the lubricant moves to the contact portion and tends to slip. In contrast, in the present invention,Heat resistanceSlippery layerCoating liquid for formingContains silyl isocyanate to provide lubricity, prevent lubricant migration and set-off, and the sameHeat resistanceIt is possible to maintain heat resistance by containing a heat-resistant resin which does not have a reactive group with an isocyanate group and is compatible with the silyl isocyanate in the slipping layer.
[0010]
  Since the silyl isocyanate used in the present invention is very easy to react and cure, when the silyl isocyanate is added to the coating solution as the heat-resistant slipping layer, the coating solution reacts with other resins over time and cures. Therefore, in the present inventionHeat resistanceSlippery layerCoating liquid for formingA heat-resistant resin having no reactive group of silyl isocyanate and an isocyanate group and having compatibility with the silyl isocyanate was contained. Heat-resistant slip layerCoating liquidIs applied onto the substrate film and dried, the silyl isocyanate itself undergoes a reaction that self-crosslinks and the crosslinking reaction is completed upon drying.Heat resistanceSlippery layerCoating liquidSince silyl isocyanate does not have a reactive group with an isocyanate group and contains a heat-resistant resin that is compatible with the silyl isocyanate, the silyl isocyanate must be further diluted in the state of a coating solution. Since self-crosslinking can be suppressed,Heat resistanceThe coating liquid of the slipping layer becomes stable without gelation,Heat resistanceThe printing surface of the slippery layer is uniform and a uniform finish can be obtained, leading to improved quality of the thermal transfer image.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described in more detail with reference to preferred embodiments.
(Base film)
The base film constituting the thermal transfer sheet of the present invention may be any base film having a conventionally known degree of heat resistance and strength, for example, about 0.5 to 50 μm, preferably about 3 to 10 μm. Polyethylene terephthalate film of thickness, 1,4-polycyclohexylene dimethylene terephthalate film, polyethylene naphthalate film, polyphenylene sulfide film, polystyrene film, polypropylene film, polysulfone film, aramid film, polycarbonate film, polyvinyl alcohol film, In addition to cellophane, cellulose derivatives such as cellulose acetate, polyethylene film, polyvinyl chloride film, nylon film, polyimide film, ionomer film, condenser paper It may be paper such as paraffin paper, nonwoven fabric, or a composite of paper, nonwoven fabric and resin.
[0012]
(Heat resistant slipping layer)
  The heat-resistant slip layer of the present invention is formed on a base film,The coating solution for the heat resistant slipping layerIt has a heat-resistant resin that does not have a reactive group of silyl isocyanate and an isocyanate group and is compatible with the silyl isocyanate. Silyl isocyanate can be represented by the following general formula.
General formula: R_n-Si- (NCO)_4-n  However, n represents the integer of 0, 1, 2, or 3, and R is either an alkyl group, an aryl group, or a vinyl group. The silyl isocyanate represented by the above general formula functions as a lubricant and has the following features. Since the reaction rate is fast and the reaction is conducted at a relatively low temperature, aging is not required and productivity is high. Silyl isocyanate is very easy to react and cure, and in the heat-resistant slipping layer coating solution, silyl isocyanate is diluted and stable, but after coating, the solvent evaporates and silyl isocyanate is self-crosslinked. A reaction takes place and the crosslinking reaction is complete when dried.
[0013]
  The heat-resistant slip layer does not have a reactive group with an isocyanate group and includes a heat-resistant resin that is compatible with the silyl isocyanate. That is, the coating solution for forming the heat-resistant slipping layer has a silyl isocyanate and a heat-resistant resin that does not have a functional group that reacts with the isocyanate group of the silyl isocyanate and is compatible with the silyl isocyanate. It is what you are doing. Specific examples of the heat-resistant resin include saturated hydrocarbon norbornene resin, polycarbonate resin, acrylic resin, and the like. Of these resins, those having a glass transition point of 100 ° C. or higher are preferably used. However, the norbornene resin has the following structural formula 1.
[0014]
[Chemical 1]

[0015]
  Also,Heat resistanceThe heat-resistant resin contained in the slipping layer does not have a functional group that reacts with an isocyanate group, and specifically has a functional group that reacts with an isocyanate such as a hydroxyl group, amino group, carboxyl group, or mercapto group of the resin. It is a resin that is not compatible with silyl isocyanate. In particular, norbornene resin is preferably used because it sufficiently satisfies the above performance.Heat resistanceSlippery layerCoating liquidThe silyl isocyanate has no reactive group with the isocyanate group, and is blended with the heat-resistant resin compatible with the silyl isocyanate, the heat-resistant resin is 5 to 2000 with respect to 100 parts by weight of the silyl isocyanate. It can be used in the range of parts by weight, and the range of 10 to 1000 parts by weight of the heat resistant resin can be particularly preferably used. If the amount of heat-resistant resin is small,Heat resistanceThe point that lacks the coating stability of the slipping layer comes out,Heat resistanceUnevenness is likely to occur on the printed surface of the slipping layer. On the other hand, an increase in the amount of the heat-resistant resin is not preferable because the sliding property with the thermal head is lowered, and thermal fusion between the thermal head and the thermal transfer sheet is likely to occur.
[0016]
  Heat resistanceSlippery layerCoating liquidSince silyl isocyanate does not have a reactive group with an isocyanate group and contains a heat-resistant resin that is compatible with the silyl isocyanate, the silyl isocyanate must be further diluted in the state of a coating solution. Since self-crosslinking can be suppressed,Heat resistanceThe coating liquid of the slipping layer becomes stable without gelation,Heat resistanceThe printed surface of the slippery layer is uniform, and a uniform finish is obtained.Heat resistanceSlippery layerCoating liquidMay be added as long as it does not interfere with the object of the present invention, unless it is mainly composed of the silyl isocyanate represented by the above general formula and the filler and lubricant are not reactively cured with the silyl isocyanate.
[0017]
Suitable fillers include, for example, inorganic fillers such as talc, kaolin, clay, calcium carbonate, magnesium hydroxide, magnesium carbonate, magnesium oxide, precipitated barium sulfate, hydrotalcite silica, acrylic resins, benzoguanamine resins, silicones. An organic filler made of Teflon or the like is preferable, and a filler having a crisp property such as talc, kaolin, and clay and having a relatively low hardness but a thermal head cleaning property is preferable.
Specifically, in the case of talc, a shot-type wear degree of 15 to 200 mg is preferable. If the wear degree is low, head wrinkles are likely to occur, and if it is high, wear of the thermal head protective layer becomes remarkable.
[0018]
In order to further improve performance and stabilize performance, it is preferable to add a lubricant to the heat resistant slipping layer. Examples of the lubricant to be added include waxes such as polyethylene wax and paraffin wax, higher aliphatic alcohols, and organopolysiloxane. , Anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, fluorosurfactants, organic carboxylic acids and derivatives thereof, and long-chain aliphatic compounds. In particular, it is preferable to use a lubricant such as a phosphate ester-based surfactant. This is because it acts supplementarily as a heat release agent when high energy is applied.
[0019]
Add the silyl isocyanate represented by the above general formula and additives as necessary, and dissolve or disperse in a solvent such as acetone, ethyl acetate, methyl ethyl ketone, toluene, xylene selected to suit the coating suitability. A slipping layer can be formed by preparing a coating solution and applying and drying the coating solution by a conventional coating means such as a gravure coater, a roll coater, or a wire bar.
The coating amount of the slipping layer is 5.0 g / m on a solid basis.² The following is preferable, preferably 0.1 to 2.0 g / m² It is possible to form a heat-resistant slipping layer having sufficient performance at a thickness of 5 mm.
In addition, the addition amount of the filler and the additive of the lubricant is 1 to 150 parts by weight, preferably 40 to 120 parts by weight, per 100 parts by weight of the binder resin forming the heat resistant slipping layer.
[0020]
In this invention, a primer layer can be provided between the said base film and a heat resistant slipping layer, and the adhesiveness of a base film and a heat resistant slipping layer can be improved.
The primer layer preferably has sufficient adhesiveness to the base film and the heat-resistant slipping layer, and has heat resistance and dimensional stability that suppress thermal deformation of the base film. The primer layer may be any one of a thermoplastic resin, various thermosetting resins, a mixed composition of various curing agents and a resin having a reactive group, and a coating composition that causes a crosslinking reaction by light and ionizing radiation. The amount is 1.0 g / m on a solid basis.² Or less, preferably 0.01 to 0.05 g / m² The thickness of is good.
In addition, in order to improve the adhesiveness of a base film and a heat-resistant slipping layer, it is also possible to perform an easily bonding process or a corona discharge process on the surface of a base film, and not providing a primer layer.
[0021]
(Heat transfer color material layer)
As the thermal transfer color material layer formed on the other surface of the base film, in the case of a sublimation type thermal transfer sheet, a layer containing a sublimation dye, that is, a heat sublimation dye layer is formed, In the case of this thermal transfer sheet, a hot-melt ink layer colored with a pigment or the like is formed.
Hereinafter, the case of a sublimation type thermal transfer sheet will be described as a representative example, but the present invention is not limited to only a sublimation type thermal transfer sheet. As the dye used for the sublimation type heat transfer color material layer, any dye conventionally used for a known heat transfer sheet can be used in the present invention and is not particularly limited. For example, some preferred dyes include red dyes, MS RED G, Macro Red Bioret
[0022]
R, Ceres Red 7B, Samaron Red HBSL, Resolin Red F3BS and the like, and yellow dyes include Holon Brilliant Yellow 6GL, PTY-52, Macrolex Yellow 6G and the like, and blue dyes Kayaset Blue 714, Waxoline Blue AP-FW, Holon Brilliant Blue-S-R, MS Blue 100, and the like.
[0023]
Examples of preferable binder resins for supporting the dyes as described above include cellulose resins such as ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxy cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, and cellulose acetate butyrate, polyvinyl alcohol, poly Examples thereof include vinyl resins such as vinyl acetate, polyvinyl butyral, polyvinyl acetoacetal and polyvinyl pyrrolidone, acrylic resins such as poly (meth) acrylate and poly (meth) acrylamide, polyurethane resins, polyamide resins and polyester resins. Of these, cellulose-based, vinyl-based, acrylic-based, urethane-based, and polyester-based resins are preferable from the viewpoints of heat resistance, dye transferability, and the like.
[0024]
The dye layer is formed by adding one or more additives such as the above-described dye and binder to the one surface of the base film as necessary, for example, a mold release agent or inorganic fine particles. , Reverse roll coating using a gravure printing method, screen printing method, gravure plate, etc., dissolved in a suitable organic solvent such as ethanol, isopropyl alcohol, cyclohexanone, DMF, or dispersed in an organic solvent or water It can be formed by applying and drying by means such as printing.
[0025]
The dye layer thus formed has a thickness of about 0.2 to 5.0 μm, preferably about 0.4 to 2.0 μm, and the sublimable dye in the dye layer is 5% by weight of the dye layer. It is suitable to be present in an amount of ˜90% by weight, preferably 10-70% by weight.
The dye layer to be formed is formed by selecting one of the dyes when the desired image is monocolor, and when the desired image is a full color image, for example, an appropriate cyan, Magenta and yellow (further black if necessary) are selected to form yellow, magenta and cyan (further black if necessary) dye layers.
[0026]
(Method for producing thermal transfer sheet)
  The method for producing a thermal transfer sheet of the present invention is a method for producing a thermal transfer sheet having a thermal transfer color material layer on one side of a base film and a heat resistant slipping layer on the other side. Contains a heat-resistant resin that has no isocyanate-reactive group and is compatible with the silyl isocyanate.Depending on the coating liquidApply the heat-resistant slip layer to the base film and dryFormedIn this case, the solvent is evaporated, and the silyl isocyanate itself is characterized in that the self-crosslinking reaction is completed.
[0027]
  The thermal transfer sheet has a thermal transfer color material layer on one side of the base film and a heat-resistant slipping layer on the other side.Heat resistanceSlippery layerCoating liquid for formingIt has a heat-resistant resin that does not have a reactive group of silyl isocyanate and an isocyanate group and is compatible with the silyl isocyanate. In the coating solution of the heat resistant slipping layer, the silyl isocyanate is diluted and stable, but after coating, the solvent evaporates and the silyl isocyanate undergoes a self-crosslinking reaction. Sometimes the self-crosslinking reaction ends. Therefore, after application of the heat resistant slipping layer, a heat treatment such as aging (heating aging) or an apparatus such as ultraviolet irradiation or electron beam irradiation is not required. On the other hand, in order to improve the heat resistance of the heat-resistant slip layer of the thermal transfer sheet, various isocyanate curing agents, reaction products with monomers and oligomers having an unsaturated bond can be used. The curing means includes heating, irradiation with ionizing radiation, etc. In the case of heating, since the unreacted material before curing is mixed in the coating liquid, the curing speed is determined from the storage stability of the coating liquid. Is done to delay. In such a case, the above manufacturing methodHeat resistanceAfter the slipping layer is applied and dried, the thermal transfer sheet can be heat-aged to cure the heat-resistant slipping layer.
[0028]
The image receiving sheet, which is a transfer material, used to form an image using the thermal transfer sheet as described above may be any one as long as its recording surface has dye acceptability for the above dyes. In the case of paper, metal, glass, synthetic resin, etc. that do not have dye acceptability, a dye accepting layer may be formed on at least one surface thereof. In the case of a heat melting type thermal transfer sheet, the material to be transferred is not particularly limited, and may be ordinary paper or plastic film.
A known thermal transfer printer can be used as it is as a printer used when performing thermal transfer using the above thermal transfer sheet and the above sheet, and is not particularly limited.
[0029]
【Example】
Next, the present invention will be described in more detail with reference examples, examples and comparative examples. In the text, “part” or “%” is based on weight unless otherwise specified.
Example 1
About 0.5 g / m of dried coating liquid A for heat-resistant slipping layer having the following composition on a polyethylene terephthalate film having a thickness of 6 μm as a base film.² Then, it was applied and dried by applying hot air at a temperature of 100 ° C.
On the other surface of the base film, a thermal transfer color material layer coating solution A having the following composition is dried at about 1.0 g / m.² It was applied and dried to form a thermal transfer color material layer to produce a thermal transfer sheet of Example 1 of the present invention.
[0030]
Coating liquid A composition for heat resistant slipping layer
10 parts of silyl isocyanate
(Matsumoto Co., Ltd., Olga Tix SIC-434)
5 parts of norbornene resin
(Arton G, manufactured by Nippon Synthetic Rubber Co., Ltd.)
Methyl ethyl ketone 5 parts
Toluene 5 parts
[0031]
Coating composition A for thermal transfer color material layer
MS-RED-G 2.00 parts
(Mitsui Toatsu Chemicals, Disper Thread 60)
Macrolex Red Violet R 1.50 parts
(Manufactured by Bayer, Disperse Violet 26)
Polyvinyl acetoacetal resin 3.50 parts
(Eslex KS-5, manufactured by Sekisui Chemical Co., Ltd.)
Methyl ethyl ketone 46.50 parts
46.50 parts of toluene
[0032]
(Example 2)
A thermal transfer sheet of Example 2 was obtained in the same manner as in Example 1 except that the following coating liquid B was used in place of the heat resistant slipping layer coating liquid A of Example 1.
Coating liquid B composition for heat resistant slipping layer
10 parts of silyl isocyanate
(Matsumoto Co., Ltd., Olga Tix SIC-434)
10 parts of norbornene resin
(Arton G, manufactured by Nippon Synthetic Rubber Co., Ltd.)
Methyl ethyl ketone 5 parts
Toluene 5 parts
[0033]
(Example 3)
A thermal transfer sheet of Example 3 was obtained in the same manner as in Example 1 except that the following coating liquid C was used in place of the heat resistant slipping layer coating liquid A of Example 1.
Coating liquid C composition for heat resistant slipping layer
10 parts of silyl isocyanate
(Matsumoto Co., Ltd., Olga Tix SIC-434)
10 parts of polycarbonate resin
(Teijin Chemicals Ltd., Panlite K-1300)
Methyl ethyl ketone 5 parts
Toluene 5 parts
[0034]
(Example 4)
A thermal transfer sheet of Example 4 was obtained in the same manner as in Example 1 except that the following coating liquid D was used in place of the slipping layer coating liquid A of Example 1.
Coating liquid D composition for heat resistant slipping layer
1 part silyl isocyanate
(Matsumoto Co., Ltd., Olga Tix SIC-434)
20 parts of norbornene resin
(Arton G, manufactured by Nippon Synthetic Rubber Co., Ltd.)
Methyl ethyl ketone 5 parts
Toluene 5 parts
[0035]
(Comparative Example 1)
A thermal transfer sheet of Comparative Example 1 was obtained in the same manner as in Example 1 except that the following coating liquid E was used in place of the slipping layer coating liquid A of Example 1.
Coating liquid E composition for heat resistant slipping layer
10 parts of silyl isocyanate
(Matsumoto Co., Ltd., Olga Tix SIC-434)
Methyl ethyl ketone 5 parts
Toluene 5 parts
[0036]
(Comparative Example 2)
The following heat-resistant slipping layer coating solution F was dried at about 1.0 g / m on a polyethylene terephthalate film having a thickness of 6 μm as a base film² It was applied and dried. Furthermore, it was heat-aged at 60 ° C. for 7 days for curing treatment to form a heat-resistant slipping layer. On the other surface of the base film, the thermal transfer color material layer coating liquid A is about 1.0 g / m when dried.² It was applied and dried to form a thermal transfer color material layer, and a thermal transfer sheet of Comparative Example 2 was produced.
Coating liquid E composition for heat resistant slipping layer
Polyvinyl butyral resin 1.60 parts
(Sekisui Chemical Co., Ltd., ESREC BX-1)
Polyisocyanate 4.23 parts
(Dai Nippon Ink Chemical Co., Ltd., Burnock D-750-45)
Phosphate-based surfactant 0.68 parts
(Daiichi Kogyo Seiyaku Co., Ltd., Prisurf A208S)
Talc (Nihon Talc, Microace L-1) 0.32 parts
Methyl ethyl ketone 38.43 parts
38.43 parts of toluene
[0037]
(Evaluation method 1)
In each of the above thermal transfer sheets, after forming the heat-resistant slipping layer, it is wound up and left in a room at 20 ° C. for 3 days. (However, in Comparative Example 2, heat aging is performed, and then the room is left in the above condition.)
After that, the thermal transfer color material layer coating solution was applied to the other surface of each thermal transfer sheet and dried to form a thermal transfer color material layer. Then, the state of the coated surface of the thermal transfer color material layer is visually observed and evaluated. Judgment criteria are as follows.
○: There is no coating unevenness and the coating surface is uniform.
X: There is coating unevenness.
[0038]
(Evaluation method 2)
The above-described thermal transfer sheet is overlaid on a conventionally used image receiving sheet. Specifically, as shown in FIG. 1, the thermal transfer color material layer of the thermal transfer sheet 3 and the image receiving surface of the image receiving sheet 4 are overlaid. It is sandwiched between the rolls 5 and a load (weight) 1 of 2000 g is applied from above the thermal head 2. Next, the image receiving sheet 4 is fixed, and the thermal transfer sheet 3 is fixed at a constant speed (500 mm) in the direction of the arrow with Tensilon (made by ORIENTEC, VCT-1000). / Min). At that time, the thermal head 2 is energized under the following conditions, and the presence or absence of thermal fusion between the thermal transfer sheet 3 and the thermal head 2 is visually observed and evaluated.
[0039]
<Printing conditions when energized>
Voltage: 18V
Pulse width: 11.25ms
Recording cycle: 22.5 ms / line
[0040]
Judgment criteria for the evaluation of the thermal fusion are as follows.
○: Thermal fusion is not recognized.
Δ: A little thermal fusion is observed.
X: Thermal fusion is observed, and the thermal transfer sheet is torn.
[0041]
(Evaluation method 3)
The above-mentioned thermal transfer sheet is cut into 3 cm square, sandwiched between dedicated sample holders, and the infrared absorption wavelength is measured with an infrared spectrophotometer (manufactured by JASCO Corporation, A-100). 2300cm^-1The presence or absence of unreacted isocyanate groups is confirmed by the presence or absence of absorption at a nearby wavelength. In addition, each thermal transfer sheet measures an infrared absorption wavelength in the state immediately after application | coating of a heat resistant slipping layer and drying. The thermal transfer sheet of Comparative Example 2 is measured immediately after application and drying of the heat resistant slipping layer and before heat aging.
[0042]
(Evaluation results)
The evaluation results are shown in Table 1.
(The following margin)
[Table 1]

[0043]
【The invention's effect】
  According to the present invention as described above, in the thermal transfer sheet having the thermal transfer color material layer on one surface of the base film and the heat resistant slip layer provided on the other surface, the heat resistant slip layerIn coating liquid to formIt contains a heat-resistant resin that does not have a reactive group of silyl isocyanate and an isocyanate group and is compatible with the silyl isocyanate, and the heat-resistant slipping layer is formed on the base film.With coating solution for heat resistant slipping layerCoating and dryingFormedWhen this is done, the solvent evaporates and the silyl isocyanate itself completes the self-crosslinking reaction. Therefore, the sliding property with the thermal head is good, and thermal fusion between the thermal head and the thermal transfer sheet does not occur.Heat resistanceThere is no slip-off of the lubricant to the surface that overlaps with the slipping layer, andHeat resistanceA thermal transfer sheet with a uniform printing surface of the slipping layer, no unevenness, and excellent heat resistance is obtained.Heat resistanceIf the silyl isocyanate is diluted in the state of the coating liquid, the slipping layer can suppress self-crosslinking,Heat resistanceThe coating liquid of the slipping layer becomes stable without gelation,Heat resistanceThe printing surface of the slippery layer is uniform and a uniform finish can be obtained, leading to improved quality of the thermal transfer image. In addition, since the silyl isocyanate of the heat resistant slipping layer is self-crosslinked when coated and dried, and the reaction is completed, after the heat resistant slipping layer is coated, heat treatment such as aging (heating aging) No equipment such as ultraviolet irradiation or electron beam irradiation is required.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a state when a thermal transfer sheet and an image receiving sheet are overlapped and the presence or absence of thermal fusion between the thermal transfer sheet and the thermal head that is being heated by the thermal head is evaluated.
[Explanation of symbols]
1 2000g weight
2 Thermal head
3 Thermal transfer sheet
4 Image-receiving sheet
5 Platen roll

Claims (3)

In a thermal transfer sheet having a thermal transfer color material layer on one side of a base film and a heat resistant slipping layer provided on the other side , silyl isocyanate and isocyanate are used as a coating liquid for forming the heat resistant slipping layer. A thermal transfer sheet characterized by having a heat-resistant resin that does not have a reactive group with a group and is compatible with the silyl isocyanate.   2. The thermal transfer sheet according to claim 1, wherein the thermal transfer color material layer is a thermal sublimable dye layer or a hot-melt ink layer. In the method for producing a thermal transfer sheet having a thermal transfer color material layer on one surface of a base film and a heat-resistant slipping layer on the other surface, the heat-resistant slipping layer is a reactive group of silyl isocyanate and an isocyanate group. the no, and the coating liquid containing the heat-resistant resin with the silyl isocyanate compatible, coating the heat-resistant slipping layer on the substrate film, when formed by drying, the solvent is evaporated And a method for producing a thermal transfer sheet, wherein the reaction of self-crosslinking of silyl isocyanate itself is completed.

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