JP3896402B2 - Optical information recording medium manufacturing method and optical information recording medium - Google Patents

Description

【００２４】
上記一般式（II）において、Ｚ¹及びＺ²は、各々独立に、５員又は６員の含窒素複素環を形成するために必要な原子団を表し、Ｒ¹及びＲ²は、各々独立に、アルキル基を表し、Ｌ¹、Ｌ²、Ｌ³、Ｌ⁴及びＬ⁵は、各々独立に、置換されていてもよいメチン基を表し、ｎ１及びｎ２は、各々独立に、０、１又は２を表し、ｐ及びｑは、各々独立に、０又は１を表し、Ｍ１は、電荷中和対イオンを表し、そしてｍ１は、分子中の電荷を中和させるために必要な０以上の数を表す。
【００２５】
上記一般式（II）で表されるシアニン色素は、下記一般式（II−１）もしくは一般式（II−２）で表される化合物であることが好ましい。
【００２６】
【化２】

【００２７】
上記一般式（II−１）及び一般式（II−２）において、Ｚ³及びＺ⁴は、各々独立に、置換基を有していてもよいベンゼン環又はナフタレン環を形成するために必要な原子団を表し、Ｒ³、Ｒ⁴、Ｒ⁵、Ｒ⁶、Ｒ⁷、及びＲ⁸は、各々独立に、炭素原子数１乃至８のアルキル基を表し、Ｒ⁹は、水素原子、炭素原子数１乃至８のアルキル基、炭素原子数７乃至１０のアラルキル基、炭素原子数６乃至１０のアリール基、炭素原子数１乃至８のアルコキシ基、ヘテロ環基、ハロゲン原子、又は炭素原子数１乃至８のカルバモイル基を表し、Ｍ２^m2-は陰イオンを表し、そしてｍ２は、１又は２を表す。
【００２８】
アゾ色素は、下記一般式（III）で表される化合物であることが好ましい。
【００２９】
【化３】

【００３０】
上記一般式（III）において、Ｍは、金属原子を表し、Ｘは、酸素原子、硫黄原子、又は＝ＮＲ¹¹を表し、Ｒ¹¹は、水素原子、アルキル基、アリール基、アシル基、アルキルスルホニル基、又はアリールスルホニル基を表し、Ｚ¹¹は、５員又は６員の含窒素複素環を形成するために必要な原子団を表し、そしてＺ¹²は、芳香環又は複素芳香環を完成するために必要な原子団を表す。
【００３１】
上記一般式（III）で表されるアゾ色素は、下記一般式（III−１）で表される化合物であることが好ましい。
【００３２】
【化４】

【００３３】
上記一般式（III−１）において、Ｍは、鉄、コバルト、ニッケル、銅、亜鉛、パラジウム、白金、又は金を表し、Ｙは、酸素原子、硫黄原子、又は＝ＮＲ¹²を表し、Ｒ¹²，Ｒ¹³、及びＲ¹⁴は、各々独立に、炭素原子数１乃至１２の置換基を有していてもよいアルキル基を表し、Ｒ¹³とＲ¹⁴は互いに連結して環を形成していてもよく、Ｒ¹⁵は、炭素原子数１乃至１２の置換基を有していてもよいアルキル基又は炭素原子数６乃至１６の置換基を有していてもよいフェニル基、又はナフチル基を表し、Ｒ¹⁶及びＲ¹⁷は、各々独立に、水素原子、ハロゲン原子、アルキル基、アリール基、シアノ基、アシル基、アルキルスルホニル基、又はアリールスルホニル基を表し、Ｒ¹⁸、Ｒ¹⁹、及びＲ²⁰は、各々独立に、水素原子、アルキル基、アリール基、ヒドロキシ基、アルコキシ基、アリールオキシ基、アミノ基、カルボンアミド基、スルホンアミド基、シアノ基、ハロゲン原子、アシル基、アルキルスルホニル基、又はアリールスルホニル基を表す。
【００３４】
オキソノール色素は、下記一般式（IV−１）又は一般式（IV-２）で表される化合物であることが好ましい。なお、一般式（IV−１）又は一般式（IV-２）で表される化合物の具体例は、例えば、特開平１０−２９７１０３号公報、同１０−３０９８７１号公報、及び同１０−３０９８７２号公報に記載されている。
【００３５】
【化５】

【００３６】
上記一般式（IV−１）または一般式（IV-２）において、Ａ²¹、Ａ²²、Ｂ²¹及びＢ²²は、各々独立に、置換基を表し、Ｙ²¹及びＺ²¹は、各々独立に、炭素環もしくは複素環を形成するために必要な原子団を表し、Ｅ及びＧは、各々独立に、共役二重結合鎖を完成するために必要な原子団を表し、Ｘ²¹は、＝Ｏ、＝ＮＲ²¹又は＝Ｃ（ＣＮ）₂を表し、Ｘ²²は、−Ｏ、−ＮＲ²¹又は−Ｃ（ＣＮ）₂を表し（但し、Ｒ²¹は置換基を表す）、Ｌ²¹、Ｌ²²、Ｌ²³、Ｌ²⁴及びＬ²⁵は各々独立に、置換されていてもよいメチン基を表し、Ｖ^k+は、カチオンを表し、ｎ３及びｎ４は、各々独立に０、１又は２を表し、ｘ及びｙは、各々独立に、０又は１を表し、そしてｋは、１〜１０の整数を表す。
【００３７】
色素記録層の形成に際して、その塗布液の調製には、フッ素化アルコールとフッ素化環状アルカンもしくはアルケンとの混合溶剤が用いられる。
フッ素化アルコールとしては、下記の一般式（Ｉ）で表される化合物を用いることが好ましい。
Ｒ−ＣＨ₂ＯＨ （Ｉ）
上記式において、Ｒは、ＣＦ₃、又はＨ（ＣＦ₂・ＣＦ₂）_nを表す。ｎは、１乃至３の整数を表す。
これらの具体例としては、ＨＣＦ₂ＣＦ₂ＣＨ₂ＯＨ、ＨＣＦ₂ＣＦ₂ＣＦ₂ＣＦ₂ＣＨ₂ＯＨ、及びＣＦ₃ＣＨ₂ＯＨを挙げることができる。特に、フッ素化アルコールとしては、２，２，３，３−テトラフルオロ−１−プロパノール（ＨＣＦ₂ＣＦ₂ＣＨ₂ＯＨ）を用いることが好ましい。
【００３８】
フッ素化環状アルカンもしくはアルケンは、４乃至６員のフッ素化環状アルカンもしくはアルケンが好ましく、更に好ましくは、５員のフッ素化環状アルカンもしくはアルケンである。フッ素化環状アルカンもしくはアルケンは、骨格の炭素原子数の０．５乃至２．０倍（更に好ましくは、炭素原子数の１．０乃至２．０倍、特に好ましくは、１．０乃至１．８倍、最も好ましくは、１．２乃至１．６倍）のフッ素原子で置換されたフッ素化環状アルカンもしくはアルケンであることが好ましい。フッ素化環状アルカンの例としては、１，１，２，２，３−ペンタフルオロシクロブタン、１，１，２，２，３，３−ヘキサフルオロシクロペンタン、１，１，２，２，３，３，４−ヘプタフルオロシクロペンタン、１，１，２，２，３，４，５−ヘプタフルオロシクロペンタン、１，１，２，２，３，３，４，４−オクタフルオロシクロペンタン、１，１，２，２，３，３，４，５−オクタフルオロシクロペンタン、及び１，１，２，２，３，３，４，４，５−ノナフルオロシクロヘキサンを挙げることができる。また、フッ素化環状アルケンの例としては、１，１，２，２，３，４−ヘキサフルオロシクロブテン、１，１，２，２，３，３，４，５−オクタフルオロシクロペンテン、及び１，１，２，２，３，３，４，４，５，６−デカフルオロシクロヘキセンを挙げることができる。これらの化合物は、例えば、特開平８−１２６０３号、同８−１４３４８７号、同９−９５４５８号、同１０−３１６５９６号、同１０−３１６５９７号、及び同１０−３１６５９８号の各公報に開示されている。尚、これらの化合物は、主に洗浄剤として有用とされているものである。
【００３９】
本発明で使用する上記フッ素化環状アルカンもしくはアルケンは、フッ素化アルコールより低沸点であることが好ましい。特に、前記２，２，３，３−テトラフルオロ−１−プロパノールより低沸点であることが好ましい。この化合物の沸点は、約１１０℃であるため、この化合物の沸点より１０℃以下の沸点のものが好ましく、更に好ましくは、２０℃以下の沸点のものであり、塗布特性などを考慮すると、沸点が、５０℃以上のものであることが好ましい。またフッ素化環状アルカンもしくはアルケンは色素に対する溶解性が比較的良好であるものが選ばれる。このような点から、本発明では、上記フッ素化環状アルカンとして、１，１，２，２，３，３，４−ヘプタフルオロシクロペンタン、１，１，２，２，３，４，５−ヘプタフルオロシクロペンタン、１，１，２，２，３，３，４，４−オクタフルオロシクロペンタン、及び１，１，２，２，３，３，４，５−オクタフルオロシクロペンタンを用いることが好ましい。１，１，２，２，３，３，４−ヘプタフルオロシクロペンタン（下記の式で表される化合物）を用いることが特に好ましい。
【００４０】
【化６】

【００４１】
上記化合物の沸点は、約８２．５℃であり、また上記アルコール溶剤に比べて色素に対する溶解性は劣るものの、色素溶剤として十分使用できることから、この化合物を上記フッ素化アルコールと併用することで、色素記録層形成用塗布液の性能、特に塗布後の該層の乾燥速度を向上させることができる。
【００４２】
フッ素化アルコールとフッ素化環状アルカンもしくはアルケンは、その混合容量比が、９５：５〜６０：４０（好ましくは、９０：１０〜７０：３０）の範囲となるように混合溶剤として用いられる。色素記録層の形成は、上記混合溶剤に色素を溶解して塗布液を調製し、この塗布液を基板表面に塗布して塗膜を形成したのち乾燥することにより行われる。尚、塗布液の調整に際しては、退色防止剤や、更に所望により結合剤を加えることもできる。また、塗布液中には酸化防止剤、ＵＶ吸収剤、可塑剤、潤滑剤など各種の添加剤を目的に応じて添加してもよい。
【００４３】
色素記録層形成用塗布液の調製に際しては、従来から知られている溶剤を用いてもよい。このような溶剤の例としては、酢酸ブチル、セロソルブアセテートなどのエステル；メチルエチルケトン、シクロヘキサノン、メチルイソブチルケトンなどのケトン；ジクロルメタン、１，２−ジクロルエタン、クロロホルムなどの塩素化炭化水素；ジメチルホルムアミドなどのアミド；シクロヘキサンなどの炭化水素；テトラヒドロフラン、エチルエーテル、ジオキサンなどのエーテル；エタノール、ｎ−プロパノール、イソプロパノール、ｎ−ブタノール、ジアセトンアルコールなどのアルコール；エチレングリコールモノメチルエーテル、エチレングリコールモノエチルエーテル、プロピレングリコールモノメチルエーテルなどのグリコールエーテル類などを挙げることができる。上記溶剤は使用する色素の溶解性などを考慮して単独または二種以上を適宜併用することができる。
【００４４】
退色防止剤の代表的な例としては、ニトロソ化合物、金属錯体、ジインモニウム塩、アミニウム塩などを挙げることができる。これらの例は、特開平２−３００２８８号、同３−２２４７９３号、あるいは同４−１４６１８９号等の各公報に記載されている。退色防止剤を併用する場合には、その使用量は、色素の量に対して、通常０．１〜５０重量％の範囲であり、好ましくは、０．５〜４５重量％の範囲、更に好ましくは、３〜４０重量％の範囲、特に５〜２５重量％の範囲である。
【００４５】
結合剤の例としては、例えば、ゼラチン、セルロース誘導体、デキストラン、ロジン、ゴムなどの天然有機高分子物質；およびポリエチレン、ポリプロピレン、ポリスチレン、ポリイソブチレン等の炭化水素系樹脂、ポリ塩化ビニル、ポリ塩化ビニリデン、ポリ塩化ビニル・ポリ酢酸ビニル共重合体等のビニル系樹脂、ポリアクリル酸メチル、ポリメタクリル酸メチル等のアクリル樹脂、ポリビニルアルコール、塩素化ポリエチレン、エポキシ樹脂、ブチラール樹脂、ゴム誘導体、フェノール・ホルムアルデヒド樹脂等の熱硬化性樹脂の初期縮合物などの合成有機高分子を挙げることができる。色素記録層の材料として結合剤を併用する場合に、結合剤の使用量は、色素１００重量部に対して、上限が２０重量部、好ましくは１０重量部、更に好ましくは５重量部にとどめるべきである。
【００４６】
このようにして調製される色素記録層の塗布液中の色素の濃度は一般に０．０１〜１０重量％の範囲にあり、好ましくは０．１〜５重量％の範囲にある。
【００４７】
塗布方法としては、スプレー法、スピンコート法、ディップ法、ロールコート法、ブレードコート法、ドクターロール法、及びスクリーン印刷法などを挙げることができる。本発明では、色素記録層の形成は、スピンコート法を利用して行うことが好ましい。色素記録層は単層でも重層でもよい。色素記録層の層厚（乾燥後の厚み）は一般に２０〜５００ｎｍの範囲にあり、好ましくは５０〜３００ｎｍの範囲にある。
【００４８】
色素記録層の上には、特に情報の再生時における反射率の向上の目的で、金属反射層が設けられていることが好ましい。金属反射層の材料である光反射性物質はレーザ光に対する反射率が高い物質であり、その例としては、Ｍｇ、Ｓｅ、Ｙ、Ｔｉ、Ｚｒ、Ｈｆ、Ｖ、Ｎｂ、Ｔａ、Ｃｒ、Ｍｏ、Ｗ、Ｍｎ、Ｒｅ、Ｆｅ、Ｃｏ、Ｎｉ、Ｒｕ、Ｒｈ、Ｐｄ、Ｉｒ、Ｐｔ、Ｃｕ、Ａｇ、Ａｕ、Ｚｎ、Ｃｄ、Ａｌ、Ｇａ、Ｉｎ、Ｓｉ、Ｇｅ、Ｔｅ、Ｐｂ、Ｐｏ、Ｓｎ、Ｂｉなどの金属及び半金属あるいはステンレス鋼を挙げることができる。これらの物質は単独で用いてもよいし、あるいは二種以上の組合せで、または合金として用いてもよい。これらのうちで好ましいものは、Ｃｒ、Ｎｉ、Ｐｔ、Ｃｕ、Ａｇ、Ａｕ、Ａｌ及びステンレス鋼である。特に好ましくは、Ａｕ金属、Ａｇ金属、あるいはこれらの合金である。好ましいＡｕ又はＡｇ合金としては、それぞれＰｔ、Ｃｕ、及びＡｌからなる群より選ばれる少なくとも一種の金属を含む合金を挙げることができる。最も好ましくは、Ａｇ金属又はＡｇ合金である。金属反射層は、例えば、光反射性物質を蒸着、スパッタリングまたはイオンプレーティングすることにより、色素記録層の上に形成することができる。金属反射層の層厚は、一般的には１０〜８００ｎｍの範囲にあり、好ましくは２０〜５００ｎｍの範囲、更に好ましくは５０〜３００ｎｍの範囲である。
【００４９】
金属反射層の上には通常、色素記録層や金属反射層を物理的および化学的に保護する目的で樹脂保護層が設けられる。保護層に用いられる材料の例としては、ＳｉＯ、ＳｉＯ₂ 、ＭｇＦ₂ 、ＳｎＯ₂ 、Ｓｉ₃ Ｎ₄ 等の無機物質、熱可塑性樹脂、熱硬化性樹脂、ＵＶ硬化性樹脂等の有機物質を挙げることができる。保護層は、例えば、プラスチックの押出加工で得られたフィルムを接着剤を介して金属反射層上及び／または基板上にラミネートすることにより形成することができる。あるいは真空蒸着、スパッタリング、塗布等の方法により設けられていてもよい。また、熱可塑性樹脂、熱硬化性樹脂の場合には、これらを適当な溶剤に溶解して塗布液を調製したのち、この塗布液を塗布し、乾燥することによっても形成することができる。ＵＶ硬化性樹脂の場合には、溶剤を用いることなくそのままもしくは適当な溶剤に溶解して塗布液を調製したのちこの塗布液を塗布し、ＵＶ光を照射して硬化させることによっても形成することができる。これらの塗布液中には、更に帯電防止剤、酸化防止剤、ＵＶ吸収剤等の各種添加剤を目的に応じて添加してもよい。本発明では、樹脂保護層が設けられていることが好ましい。樹脂保護層の層厚は一般には０．１〜１００μｍの範囲にある。この樹脂保護層は、基板の色素記録層が設けられていない側にも耐傷性、耐湿性を高める目的で設けることもできる。
【００５０】
ＣＤ−Ｒ型の光ディスクを用いた光情報の記録再生は、例えば、次のように行われる。ＣＤ−Ｒ型の光ディスクの場合には、通常のＣＤフォーマットの場合の１倍速（１．２〜１．４ｍ／秒）で記録再生が可能である共に、２倍速、４倍速、６倍速、もしくはそれ以上の高速での記録再生も可能である。
光ディスクを所定の定線速度（ＣＤフォーマットの場合は１．２〜１．４ｍ／秒）または所定の定角速度にて回転させながら、基板側から半導体レーザ光などの記録用の光を照射する。この光の照射により、記録層の照射部分がその光を吸収して局所的に温度上昇し、ピットが生成してその光学特性を変えることにより情報が記録される。記録光としては５００〜８５０ｎｍの範囲の発振波長を有する半導体レーザービームが用いられる。用いられるレーザービームの波長は好ましくは５００〜８００ｎｍの範囲である。ＣＤ−Ｒ型の光ディスクにおいては、７７０〜７９０ｎｍの範囲の波長が適している。上記のように記録された情報の再生は、光ディスクを所定の定線速度で回転させながら半導体レーザ光を基板側から照射して、その反射光を検出することにより行うことができる。
【００５１】
以上の記載は、ＣＤ−Ｒ型の光ディスクの製造方法を例にして本発明の光情報記録媒体の製造方法を説明したものであるが、ＤＶＤ−Ｒ型の光ディスクも同様な方法で製造することができる。
【００５２】
【実施例】
以下に本発明の実施例と比較例とを記載する。
［実施例１］
【００５３】
【化７】

【００５４】
上記のインドレニン系シアニン色素１．００ｇを２，２，３，３−テトラフルオロ−１−プロパノール（ＴＦＰ）９５ｍＬと１，１，２，２，３，３，４−ヘプタフルオロシクロペンタン（商品名：ゼオローラＨ、日本ゼオン（株）製）５ｍＬとからなる混合溶剤に添加し、これに１時間超音波を印加して攪拌溶解させ、記録層形成用塗布液を調製した。
この塗布液を、表面にスパイラル状のプレグルーブ（トラックピッチ：１．６μｍ、プレグルーブ幅：５００ｎｍ、プレグルーブの深さ：１７５ｎｍ）が射出成形により形成されたポリカーボネート基板（外径：１２０ｍｍ、内径：１５ｍｍ、厚さ：１．２ｍｍ）のそのプレグルーブ側の表面に、スピンコートにより塗布、乾燥して色素記録層（厚さ（プレグルーブ内）：１３０ｎｍ）を形成した。
【００５５】
次に、ＤＣマグネトロンスパッタ装置を用いて色素記録層上に銀をスパッタして、膜厚約１５０ｎｍの金属反射層を形成した。更に該金属反射層上に、ＵＶ硬化性樹脂（商品名：ダイキュアクリアＳＤ−３１８、大日本インキ化学工業（株）製）をスピンコートにより塗布した後、メタルハライドランプにて紫外線を照射し、硬化させ、層厚約８μｍの樹脂保護層を形成した。
【００５６】
以上の工程により、基板、色素記録層、金属反射層、及び樹脂保護層がこの順で積層されてなる本発明に従うＣＤ−Ｒ型の光ディスク（以下、単にＣＤ−Ｒ）を製造した。
【００５７】
［実施例２〜５］
実施例１において、色素記録層の塗布液の調製に際し、２，２，３，３−テトラフルオロ−１−プロパノールと１，１，２，２，３，３，４−ヘプタフルオロシクロペンタンとの混合容量比を表１に示すように変更すること以外は同様にして、本発明に従うＣＤ−Ｒ（実施例５以外）を製造した。
【００５８】
［比較例１］
実施例１において、色素記録層の塗布液の調製に際し、２，２，３，３−テトラフルオロ−１−プロパノール１００ｍＬとし、１，１，２，２，３，３，４−ヘプタフルオロシクロペンタンを使用しなかったこと以外は同様にして、比較用のＣＤ−Ｒを製造した。
【００５９】
［光情報記録媒体としての評価］
（１）塗布後の色素記録層の乾燥所要時間
実施例及び比較例の光ディスクの製造において、基板上に色素記録層形成用塗布液をスピンコート装置から滴下し、該塗布後の色素記録層表面が乾燥するまでの所要時間を目視により測定した（色素記録層表面の乾燥によって該層の塗布表面の光沢が外周側に向かって徐々に変化するため、この光沢の変化を目視により観察した）。
【００６０】
（２）ジッターの測定
実施例及び比較例の光ディスクに、ＯＭＴ２０００（パルステック社製）を用いて波長７８０ｎｍのレーザ光をＮＡ０．５のピックアップを用い、定線速度４．８ｍ／秒で、ＥＦＭ信号を、記録パワーを３〜１０ｍＷまで変化させて最適記録パワーで記録した。その後、ＣＤ−ＣＡＴＳ（オーディオディベロップメント社製）を用いて波長７８０ｎｍのレーザ光をＮＡ０．４５のピックアップを用い、定線速度１．２ｍ／秒、０．５ｍＷのレーザパワーで記録信号を再生し、基板の中心から４０ｍｍの位置における１１Ｔランドジッター（ピット間ジッター）をＴＩＡ（ヒューレットパッカード社製）を用いて測定した。ジッター値は小さいほど記録信号が均一であることを示す。評価結果を表１に示す。
【００６１】
【表１】

【００６２】
表１の結果から、フッ素化アルコール（ＴＦＰ）と１，１，２，２，３，３，４−ヘプタフルオロシクロペンタン（ゼオローラＨ）との混合溶剤を用いて調製した塗布液を使用して色素記録層を設けた本発明に従う光ディスク（実施例１〜５）の場合には、フッ素化アルコール（ＴＦＰ）溶剤を単独で用いて調製した塗布液を使用して色素記録層を設けた従来の光ディスク（比較例１）に比べて塗布後の色素記録層の乾燥所要時間を短縮できることがわかる。特に、実施例１〜４に見られるように、フッ素化アルコールと１，１，２，２，３，３，４−ヘプタフルオロシクロペンタンとの混合容量比が、９５：５〜６０：４０の場合には、塗布後の色素記録層の乾燥所要時間の短縮と共に良好なジッターが達成されることがわかる。
【００６３】
【発明の効果】
本発明に従う製造方法では、光情報記録媒体の色素記録層用の塗布液の調製に際して、溶剤として、フッ素化アルコールを主体にしてこれとフッ素化環状アルカンもしくはアルケン（特に１，１，２，２，３，３，４−ヘプタフルオロシクロペンタン）とからなる混合溶剤を使用しているため、従来のフッ素化アルコール溶剤を単独で使用した場合に比べて塗布後の色素記録層の乾燥速度を上げることができる。従って、色素記録層形成工程における所要時間を短縮することが可能となり、生産性を向上させることができる。また、フッ素化環状アルカンもしくはアルケン（特に１，１，２，２，３，３，４−ヘプタフルオロシクロペンタン）は、ポリカーボネート製基板を溶かすことがなく、また、フッ素化アルコール溶剤に比べて色素に対する溶解性は劣るものの、フッ素化アルコールと併用することで良好な塗布特性を有する塗布液の調製が可能となり、従って、均一な色素記録層の形成が可能であり、良好な記録再生特性を示す光情報記録媒体を製造することができる。更にフッ素化環状アルカンもしくはアルケン（特に１，１，２，２，３，３，４−ヘプタフルオロシクロペンタン）は、フッ素化アルコールに比べ安価に入手可能であるために、製造コストを下げることができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical information recording medium manufacturing method and an optical information recording medium including a step of coating and forming a dye recording layer capable of recording information using a laser beam on a transparent disk-shaped substrate.
[0002]
[Prior art]
An optical information recording medium (write-once type optical disc) capable of recording information only once by laser light is known as a write-once type CD (so-called CD-R). A typical structure of a CD-R type optical disk is a transparent disk-shaped substrate in which a recording layer made of an organic dye, a reflective layer made of metal such as gold, and a protective layer made of resin are laminated in this order. . Information writing (recording) on this CD-R type optical disc is generally performed by irradiating the optical disc with laser light in the near-infrared region (usually laser light having a wavelength near 780 nm), and irradiating the dye recording layer. The portion absorbs the light and the temperature rises locally, causing a physical or chemical change (for example, generation of pits) to change its optical properties. On the other hand, information reading (reproduction) is usually performed by irradiating the optical disk with laser light having the same wavelength as the recording laser light, and recording is performed by changing the optical characteristics of the dye recording layer (generating pits, etc.). This is performed by detecting a difference in reflectance between a portion) and a portion not changed (unrecorded portion).
[0003]
Recently, there has been a demand for an optical information recording medium having a larger recording capacity, and a write-once DVD (digital video disk) (DVD-R) has been proposed as a response to this demand (for example, "Nikkei New Media" separate volume "DVD", published in 1995). In this document, as a write-once DVD-R type optical disc corresponding to the CD-R type optical disc, a guide groove (pre-groove) for tracking the irradiated laser beam is compared with the CD-R type. On a transparent disk-like substrate formed to be less than half (0.74 to 0.8 μm), a recording layer made of an organic dye, and usually a metal reflective layer and a protective layer made of resin on the recording layer Of the two laminates provided with a recording layer inside and bonded with an adhesive, or one of the two laminates is replaced with a disk-shaped protective plate In addition, a configuration in which a recording layer, a metal reflection layer, and a resin protective layer are provided in order on only one substrate is described. Information is written (recorded) and read (reproduced) on the DVD-R type optical disc. Laser light having a wavelength shorter than 780 nm generally used in the CD-R type optical disc (usually 600 to (Laser light in a wavelength range of 700 nm) is performed.
[0004]
As a substrate material for the above-mentioned CD-R type and DVD-R type optical disks, polycarbonate is often used because of its high dimensional stability. A spiral guide groove (pre-groove) is usually formed on the surface of the substrate, and the dye recording layer is provided on the surface. In general, the dye recording layer is formed by preparing a coating solution in which a dye is dissolved in a solvent and then applying the coating solution using a spin coating method. For the preparation of the coating solution, for example, a fluorine-containing compound is generally used as a solvent for dissolving the dye (Japanese Patent Laid-Open No. 63-159090). Generally, there is a problem that the dye as a recording material has low solubility in a solvent. However, the above fluorine-containing compound exhibits relatively good solubility in the dye and the surface of the polycarbonate substrate (unevenness of the pregroove). It has excellent characteristics such as not dissolving. In the above publication, an example using 2,2,3,3-tetrafluoro-1-propanol is specifically described.
[0005]
[Problems to be solved by the invention]
According to the study of the present inventor, a dye-containing coating solution prepared using the above fluorinated alcohol (particularly 2,2,3,3-tetrafluoro-1-propanol) is used, and a dye is formed using a spin coating method. When the recording layer is formed, it is possible to form a dye recording layer having a relatively uniform thickness, but the coating characteristics that the drying of the dye recording layer after coating takes a relatively long time are still improved. It turned out that there was a point. For this reason, there is a problem that the dye recording layer forming process takes a long time and the production line tends to be stagnant.
[0006]
The main object of the present invention is to shorten the drying time after coating in the coating forming step of the dye recording layer and to efficiently form the dye recording layer, thereby realizing an optical information recording medium realizing high productivity. It is in providing the manufacturing method of.
[0007]
[Means for Solving the Problems]
The present inventor has eagerly studied for a solvent for preparing a coating solution that exhibits a relatively high solubility in a dye and can improve the coating properties of the coating solution after preparation. As a result, the dye recording layer can be coated by using a fluorinated cyclic alkane or alkene (preferably 1,1,2,2,3,3,4-heptafluorocyclopentane) mixed with a fluorinated alcohol solvent. It has been found that the formation can be performed in a short time as compared with the prior art, and therefore an optical information recording medium can be manufactured with high productivity. Thus, as a solvent for preparing the coating liquid, a spin-coating method can be used by mixing and using the above-mentioned solvent having a low boiling point compared to fluorinated alcohol, particularly 2,2,3,3-tetrafluoro-1-propanol. It was found that the evaporation of the solvent in the dye recording layer after coating in the coating forming step by the above was accelerated, the drying time could be shortened, and the dye recording layer could be formed efficiently. It was also found that a coating solution capable of forming a uniform dye recording layer with almost no coating unevenness can be prepared by using a mixture of a fluorinated cyclic alkane or alkene and the fluorinated alcohol.
[0008]
The present invention relates to a method for producing an optical information recording medium including a step of coating and forming a dye recording layer capable of recording information by irradiation with laser light on a transparent disk-shaped substrate. The mixing volume ratio of fluorinated alcohol and fluorinated cyclic alkane or alkene 95: 5-60: 40 A method for producing an optical information recording medium, comprising: preparing a coating solution by dissolving a dye in a mixed solvent mixed so as to satisfy the following range; and applying the coating solution on a substrate and drying the coating solution It is in.
[0009]
In the present invention, a dye exhibiting a change in physical properties upon irradiation with laser light has a mixing volume ratio of fluorinated alcohol and fluorinated cyclic alkane or alkene. 95: 5-60: 40 There is also a dye solution which is dissolved in a mixed solvent in the above range.
[0010]
The present invention of Optical information recording medium Can be produced using the above dye solution .
[0011]
The method for producing an optical information recording medium of the present invention is preferably in the following manner.
(1) A fluorinated alcohol and a fluorinated cyclic alkane or alkene are mixed, and the mixing volume ratio is in the range of 95: 5 to 60:40 (more preferably 90:10 to 70:30). A method for producing an optical information recording medium used as a mixed solvent.
(2) As a fluorinated alcohol, the following general formula (I):
R-CH ₂ OH (I)
[Wherein R is CF _Three Or H (CF ₂ ・ CF ₂ ) _n N represents an integer of 1 to 3. ]
The manufacturing method of the optical information recording medium using the compound represented by these.
(3) A method for producing an optical information recording medium using 2,2,3,3-tetrafluoro-1-propanol as the fluorinated alcohol.
(4) Use 2,2,3,3-tetrafluoro-1-propanol as the fluorinated alcohol, and lower than 2,2,3,3-tetrafluoro-1-propanol as the fluorinated cyclic alkane or alkene. A method for producing an optical information recording medium using a solvent having a boiling point.
(5) A method for producing an optical information recording medium using 1,1,2,2,3,3,4-heptafluorocyclopentane as the fluorinated cyclic alkane.
[0012]
(6) A method for producing an optical information recording medium, wherein the dye recording layer is formed by a spin coating method.
(7) A dye solution using a cyanine dye, an azo dye, or an oxonol dye as the dye.
(8) The optical information recording medium has a configuration in which a dye recording layer, a metal reflection layer, and a resin protective layer are provided in this order on a transparent disk substrate.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
In the production method of the optical information recording medium of the present invention, when the dye recording layer is formed, the mixing capacity ratio of the fluorinated alcohol and the fluorinated cyclic alkane or alkene is used as a solvent to prepare the dye-containing coating solution. 95: 5-60: 40 It is characterized by using a mixed solvent in the range of. The optical information recording medium manufactured according to the manufacturing method of the present invention includes a CD-R type optical disk and DVD having a dye recording layer formed using a coating solution prepared using the specific mixed solvent as described above. -R type optical discs are included. In this specification, a method for manufacturing an optical information recording medium of the present invention will be described by taking a CD-R type optical disc as an example.
[0014]
A typical example of a CD-R type optical disk is manufactured by laminating a dye recording layer, a metal reflective layer, and a resin protective layer in this order on a transparent disk-shaped substrate. Hereinafter, a method for producing an optical information recording medium including a transparent substrate, a dye recording layer, a metal reflection layer, and a resin protective layer will be described in order as an example.
[0015]
The transparent substrate can be arbitrarily selected from various materials used as a substrate of a conventional optical information recording medium. Examples of the substrate material include glass; polycarbonate; acrylic resin such as polymethyl methacrylate; vinyl chloride resin such as polyvinyl chloride and vinyl chloride copolymer; epoxy resin; amorphous polyolefin and polyester. These materials may be used in combination as desired. These materials can be used as a film or as a rigid substrate. Among the above materials, polycarbonate is preferable from the viewpoint of moisture resistance, dimensional stability, price, and the like.
[0016]
An undercoat layer may be provided on the surface of the substrate on which the dye recording layer is provided for the purpose of improving the flatness, improving the adhesive force, and preventing the recording layer from being altered. Examples of the material for the undercoat layer include polymethyl methacrylate, acrylic acid / methacrylic acid copolymer, styrene / maleic anhydride copolymer, polyvinyl alcohol, N-methylol acrylamide, styrene / vinyl toluene copolymer, chlorosulfonated. High molecular substances such as polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, vinyl acetate / vinyl chloride copolymer, ethylene / vinyl acetate copolymer, polyethylene, polypropylene, polycarbonate; and silane coupling agents And the like.
[0017]
The undercoat layer is prepared by dissolving or dispersing the above substances in an appropriate solvent to prepare a coating solution, and then applying the coating solution to the substrate surface using a coating method such as spin coating, dip coating, or extrusion coating. Can be formed. The thickness of the undercoat layer is generally in the range of 0.005 to 20 μm, preferably in the range of 0.01 to 10 μm.
[0018]
On the substrate (or undercoat layer), it is preferable that irregularities (pregrooves) representing information such as tracking grooves or address signals are formed. This pregroove is preferably formed directly on the substrate when a resin material such as polycarbonate is injection molded or extruded.
[0019]
Further, the pregroove may be formed by providing a pregroove layer. As a material of the pregroove layer, a mixture of at least one monomer (or oligomer) of monoester, diester, triester and tetraester of acrylic acid and a photopolymerization initiator can be used. The pregroove layer is formed, for example, by first applying a mixed liquid composed of the above-mentioned acrylic acid ester and polymerization initiator on a precisely manufactured matrix (stamper), and further placing a substrate on this coating liquid layer. After that, the coating layer is cured by irradiating ultraviolet rays through the substrate or the mother die, and the substrate and the coating layer are fixed. Subsequently, it can obtain by peeling a board | substrate from a mother mold. The thickness of the pregroove layer is generally in the range of 0.05 to 100 μm, preferably in the range of 0.1 to 50 μm.
[0020]
The depth of the pregroove is preferably in the range of 0.01 to 0.3 μm, and the half width is preferably in the range of 0.2 to 0.9 μm. In addition, by setting the depth of the pregroove in the range of 0.15 to 0.2 [mu] m, it is possible to improve the sensitivity with almost no decrease in reflectance, which is particularly preferable. Therefore, such an optical disk (an optical disk in which a dye recording layer and a metal reflection layer are formed on a deep groove substrate) has high sensitivity, and can be recorded with low laser power. There is an advantage that it can be used or the service life of the semiconductor laser can be extended.
[0021]
A dye recording layer is provided on the substrate. The dye used for forming the dye recording layer is not particularly limited. For example, cyanine dyes, phthalocyanine dyes, imidazoquinoxaline dyes, azo dyes, pyrylium / thiopyrylium dyes, azurenium dyes, squarylium dyes, metal complex dyes such as Ni and Cr, naphthoquinone dyes, anthraquinone dyes, indophenol dyes, merocyanine dyes, oxonol dyes And naphthoaniline dyes, triphenylmethane dyes, triallylmethane dyes, aminium / diimonium dyes and nitroso compounds. Of these dyes, cyanine dyes, phthalocyanine dyes, azo dyes, azurenium dyes, squarylium dyes, oxonol dyes and imidazoquinoxaline dyes are preferable. Particularly preferred are cyanine dyes, azo dyes, and oxonol dyes.
[0022]
The cyanine dye is preferably a compound represented by the following general formula (II). Specific examples of the cyanine dye represented by formula (II) are described in, for example, JP-A-4-175188, JP-A-10-151861, and JP-A-11-58973.
[0023]
[Chemical 1]

[0024]
In the above general formula (II), Z ¹ And Z ² Each independently represents an atomic group necessary to form a 5- or 6-membered nitrogen-containing heterocyclic ring; ¹ And R ² Each independently represents an alkyl group, L ¹ , L ² , L ^Three , L ^Four And L ^Five Each independently represents an optionally substituted methine group, n1 and n2 each independently represent 0, 1 or 2, p and q each independently represent 0 or 1, M1 Represents a charge neutralizing counterion, and m1 represents a number of 0 or more necessary to neutralize the charge in the molecule.
[0025]
The cyanine dye represented by the general formula (II) is preferably a compound represented by the following general formula (II-1) or general formula (II-2).
[0026]
[Chemical 2]

[0027]
In the above general formula (II-1) and general formula (II-2), Z ^Three And Z ^Four Each independently represents an atomic group necessary for forming an optionally substituted benzene ring or naphthalene ring; ^Three , R ^Four , R ^Five , R ⁶ , R ⁷ And R ⁸ Each independently represents an alkyl group having 1 to 8 carbon atoms; ⁹ Is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, a heterocyclic group, a halogen atom, Represents an atom or a carbamoyl group having 1 to 8 carbon atoms; ^m2- Represents an anion, and m2 represents 1 or 2.
[0028]
The azo dye is preferably a compound represented by the following general formula (III).
[0029]
[Chemical 3]

[0030]
In the general formula (III), M represents a metal atom, and X represents an oxygen atom, a sulfur atom, or = NR. ¹¹ Represents R ¹¹ Represents a hydrogen atom, an alkyl group, an aryl group, an acyl group, an alkylsulfonyl group, or an arylsulfonyl group; ¹¹ Represents an atomic group necessary to form a 5- or 6-membered nitrogen-containing heterocycle, and Z ¹² Represents an atomic group necessary for completing an aromatic ring or a heteroaromatic ring.
[0031]
The azo dye represented by the general formula (III) is preferably a compound represented by the following general formula (III-1).
[0032]
[Formula 4]

[0033]
In the general formula (III-1), M represents iron, cobalt, nickel, copper, zinc, palladium, platinum, or gold, and Y represents an oxygen atom, a sulfur atom, or = NR. ¹² Represents R ¹² , R ¹³ And R ¹⁴ Each independently represents an alkyl group which may have a substituent of 1 to 12 carbon atoms; ¹³ And R ¹⁴ May be linked to each other to form a ring, and R ¹⁵ Represents an alkyl group which may have a substituent having 1 to 12 carbon atoms, a phenyl group which may have a substituent having 6 to 16 carbon atoms, or a naphthyl group; ¹⁶ And R ¹⁷ Each independently represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, a cyano group, an acyl group, an alkylsulfonyl group, or an arylsulfonyl group; ¹⁸ , R ¹⁹ And R ²⁰ Are each independently a hydrogen atom, alkyl group, aryl group, hydroxy group, alkoxy group, aryloxy group, amino group, carbonamido group, sulfonamido group, cyano group, halogen atom, acyl group, alkylsulfonyl group, or Represents an arylsulfonyl group.
[0034]
The oxonol dye is preferably a compound represented by the following general formula (IV-1) or general formula (IV-2). Specific examples of the compound represented by the general formula (IV-1) or the general formula (IV-2) include, for example, JP-A Nos. 10-297103, 10-309871, and 10-309872. It is described in the publication.
[0035]
[Chemical formula 5]

[0036]
In the general formula (IV-1) or (IV-2), A ^{twenty one} , A ^{twenty two} , B ^{twenty one} And B ^{twenty two} Each independently represents a substituent, Y ^{twenty one} And Z ^{twenty one} Each independently represents an atomic group necessary to form a carbocyclic or heterocyclic ring, E and G each independently represent an atomic group necessary to complete a conjugated double bond chain, and X ^{twenty one} Are = O, = NR ^{twenty one} Or = C (CN) ₂ X ^{twenty two} Are -O, -NR ^{twenty one} Or -C (CN) ₂ (However, R ^{twenty one} Represents a substituent), L ^{twenty one} , L ^{twenty two} , L ^{twenty three} , L ^{twenty four} And L ^{twenty five} Each independently represents an optionally substituted methine group; ^{k +} Represents a cation, n3 and n4 each independently represent 0, 1 or 2, x and y each independently represent 0 or 1, and k represents an integer of 1 to 10.
[0037]
In forming the dye recording layer, a mixed solvent of a fluorinated alcohol and a fluorinated cyclic alkane or alkene is used for preparing the coating solution.
As the fluorinated alcohol, it is preferable to use a compound represented by the following general formula (I).
R-CH ₂ OH (I)
In the above formula, R is CF _Three Or H (CF ₂ ・ CF ₂ ) _n Represents. n represents an integer of 1 to 3.
Specific examples of these include HCF ₂ CF ₂ CH ₂ OH, HCF ₂ CF ₂ CF ₂ CF ₂ CH ₂ OH and CF _Three CH ₂ OH can be mentioned. In particular, fluorinated alcohols include 2,2,3,3-tetrafluoro-1-propanol (HCF ₂ CF ₂ CH ₂ OH) is preferably used.
[0038]
The fluorinated cyclic alkane or alkene is preferably a 4- to 6-membered fluorinated cyclic alkane or alkene, and more preferably a 5-membered fluorinated cyclic alkane or alkene. The fluorinated cyclic alkane or alkene is 0.5 to 2.0 times the number of carbon atoms in the skeleton (more preferably 1.0 to 2.0 times the number of carbon atoms, and particularly preferably 1.0 to 1. It is preferably a fluorinated cyclic alkane or alkene substituted with 8 times, most preferably 1.2 to 1.6 times fluorine atoms. Examples of fluorinated cyclic alkanes include 1,1,2,2,3-pentafluorocyclobutane, 1,1,2,2,3,3-hexafluorocyclopentane, 1,1,2,2,3, 3,4-heptafluorocyclopentane, 1,1,2,2,3,4,5-heptafluorocyclopentane, 1,1,2,2,3,3,4,4-octafluorocyclopentane, 1,2,2,3,3,4,5-octafluorocyclopentane and 1,1,2,2,3,3,4,4,5-nonafluorocyclohexane. Examples of fluorinated cyclic alkenes include 1,1,2,2,3,4-hexafluorocyclobutene, 1,1,2,2,3,3,4,5-octafluorocyclopentene, and 1 1,2,2,3,3,4,4,5,6-decafluorocyclohexene. These compounds are disclosed in, for example, JP-A Nos. 8-12603, 8-143487, 9-95458, 10-316596, 10-316597, and 10-316598. ing. These compounds are mainly useful as cleaning agents.
[0039]
The fluorinated cyclic alkane or alkene used in the present invention preferably has a lower boiling point than the fluorinated alcohol. In particular, the boiling point is preferably lower than that of 2,2,3,3-tetrafluoro-1-propanol. Since the boiling point of this compound is about 110 ° C., the boiling point of this compound is preferably 10 ° C. or less, more preferably 20 ° C. or less. However, it is preferable that it is 50 degreeC or more. A fluorinated cyclic alkane or alkene having a relatively good solubility in a dye is selected. From such a point, in the present invention, 1,1,2,2,3,3,4-heptafluorocyclopentane, 1,1,2,2,3,4,5- Use heptafluorocyclopentane, 1,1,2,2,3,3,4,4-octafluorocyclopentane, and 1,1,2,2,3,3,4,5-octafluorocyclopentane Is preferred. It is particularly preferable to use 1,1,2,2,3,3,4-heptafluorocyclopentane (a compound represented by the following formula).
[0040]
[Chemical 6]

[0041]
The boiling point of the compound is about 82.5 ° C., and although the solubility in the dye is inferior to that of the alcohol solvent, it can be sufficiently used as a dye solvent. By using this compound in combination with the fluorinated alcohol, The performance of the coating liquid for forming the dye recording layer, particularly the drying speed of the layer after coating can be improved.
[0042]
The mixing volume ratio of the fluorinated alcohol and the fluorinated cyclic alkane or alkene is 95: 5 to 60:40. ( Preferably, it is used as a mixed solvent so that it may become the range of 90: 10-70: 30). The dye recording layer is formed by dissolving a dye in the above mixed solvent to prepare a coating solution, coating the coating solution on the substrate surface to form a coating film, and then drying the coating solution. In preparing the coating solution, a fading preventing agent and, if desired, a binder may be added. Various additives such as an antioxidant, a UV absorber, a plasticizer, and a lubricant may be added to the coating solution depending on the purpose.
[0043]
In preparing the dye recording layer forming coating solution, a conventionally known solvent may be used. Examples of such solvents include esters such as butyl acetate and cellosolve acetate; ketones such as methyl ethyl ketone, cyclohexanone and methyl isobutyl ketone; chlorinated hydrocarbons such as dichloromethane, 1,2-dichloroethane and chloroform; amides such as dimethylformamide. Hydrocarbons such as cyclohexane; ethers such as tetrahydrofuran, ethyl ether, dioxane; alcohols such as ethanol, n-propanol, isopropanol, n-butanol, diacetone alcohol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl Examples include glycol ethers such as ether. These solvents may be used alone or in combination of two or more in consideration of the solubility of the dye used.
[0044]
Typical examples of the anti-fading agent include nitroso compounds, metal complexes, diimmonium salts and aminium salts. Examples of these are described in JP-A-2-300288, JP-A-3-224793, JP-A-4-146189, and the like. When the anti-fading agent is used in combination, the amount used is usually in the range of 0.1 to 50% by weight, preferably in the range of 0.5 to 45% by weight, more preferably relative to the amount of the dye. Is in the range of 3-40% by weight, in particular in the range of 5-25% by weight.
[0045]
Examples of binders include, for example, natural organic polymer materials such as gelatin, cellulose derivatives, dextran, rosin, and rubber; and hydrocarbon resins such as polyethylene, polypropylene, polystyrene, and polyisobutylene, polyvinyl chloride, and polyvinylidene chloride. , Vinyl resins such as polyvinyl chloride / polyvinyl acetate copolymers, acrylic resins such as polymethyl acrylate and polymethyl methacrylate, polyvinyl alcohol, chlorinated polyethylene, epoxy resins, butyral resins, rubber derivatives, phenol / formaldehyde Examples thereof include synthetic organic polymers such as an initial condensate of a thermosetting resin such as a resin. When a binder is used in combination as a material for the dye recording layer, the upper limit of the amount of binder used should be 20 parts by weight, preferably 10 parts by weight, and more preferably 5 parts by weight with respect to 100 parts by weight of the dye. It is.
[0046]
The concentration of the dye in the dye recording layer coating solution thus prepared is generally in the range of 0.01 to 10% by weight, preferably in the range of 0.1 to 5% by weight.
[0047]
Examples of the coating method include a spray method, a spin coating method, a dip method, a roll coating method, a blade coating method, a doctor roll method, and a screen printing method. In the present invention, the dye recording layer is preferably formed using a spin coating method. The dye recording layer may be a single layer or a multilayer. The layer thickness (thickness after drying) of the dye recording layer is generally in the range of 20 to 500 nm, preferably in the range of 50 to 300 nm.
[0048]
A metal reflective layer is preferably provided on the dye recording layer for the purpose of improving the reflectance particularly during information reproduction. The light-reflective substance that is a material of the metal reflective layer is a substance having a high reflectance with respect to laser light. Examples thereof include Mg, Se, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Co, Ni, Ru, Rh, Pd, Ir, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Si, Ge, Te, Pb, Po, Sn, Mention may be made of metals such as Bi and metalloids or stainless steel. These substances may be used alone or in combination of two or more or as an alloy. Among these, Cr, Ni, Pt, Cu, Ag, Au, Al, and stainless steel are preferable. Particularly preferred are Au metal, Ag metal, or alloys thereof. Preferable Au or Ag alloy includes an alloy containing at least one metal selected from the group consisting of Pt, Cu, and Al. Most preferably, it is Ag metal or Ag alloy. The metal reflective layer can be formed on the dye recording layer, for example, by vapor deposition, sputtering or ion plating of a light reflective material. The thickness of the metal reflective layer is generally in the range of 10 to 800 nm, preferably in the range of 20 to 500 nm, and more preferably in the range of 50 to 300 nm.
[0049]
A resin protective layer is usually provided on the metal reflective layer for the purpose of physically and chemically protecting the dye recording layer and the metal reflective layer. Examples of materials used for the protective layer include SiO, SiO ₂ , MgF ₂ , SnO ₂ , Si _Three N _Four And inorganic materials such as thermoplastic resins, thermosetting resins, and UV curable resins. The protective layer can be formed, for example, by laminating a film obtained by extrusion of plastic on a metal reflective layer and / or a substrate via an adhesive. Or you may provide by methods, such as vacuum evaporation, sputtering, and application | coating. In the case of a thermoplastic resin or a thermosetting resin, it can also be formed by dissolving these in a suitable solvent to prepare a coating solution, and then applying and drying the coating solution. In the case of a UV curable resin, it can also be formed by preparing a coating solution as it is without using a solvent or dissolving it in a suitable solvent, and then applying the coating solution and curing it by irradiating with UV light. Can do. In these coating liquids, various additives such as an antistatic agent, an antioxidant, and a UV absorber may be added according to the purpose. In the present invention, a resin protective layer is preferably provided. The thickness of the resin protective layer is generally in the range of 0.1 to 100 μm. This resin protective layer can also be provided on the side of the substrate where the dye recording layer is not provided for the purpose of enhancing scratch resistance and moisture resistance.
[0050]
For example, recording / reproduction of optical information using a CD-R type optical disc is performed as follows. In the case of a CD-R type optical disc, recording / reproduction can be performed at 1 × speed (1.2 to 1.4 m / sec) in the case of a normal CD format, and at the same time, 2 × speed, 4 × speed, 6 × speed, or Recording and playback at a higher speed is possible.
While the optical disk is rotated at a predetermined constant linear velocity (1.2 to 1.4 m / second in the case of a CD format) or a predetermined constant angular velocity, recording light such as semiconductor laser light is irradiated from the substrate side. By this light irradiation, the irradiated portion of the recording layer absorbs the light and the temperature rises locally, pits are generated and information is recorded by changing the optical characteristics. As the recording light, a semiconductor laser beam having an oscillation wavelength in the range of 500 to 850 nm is used. The wavelength of the laser beam used is preferably in the range of 500 to 800 nm. A wavelength in the range of 770 to 790 nm is suitable for a CD-R type optical disc. The information recorded as described above can be reproduced by irradiating the semiconductor laser light from the substrate side while rotating the optical disk at a predetermined constant linear velocity and detecting the reflected light.
[0051]
In the above description, the manufacturing method of the optical information recording medium of the present invention is described by taking the manufacturing method of the CD-R type optical disc as an example. However, the DVD-R type optical disc should be manufactured by the same method. Can do.
[0052]
【Example】
Examples of the present invention and comparative examples will be described below.
[Example 1]
[0053]
[Chemical 7]

[0054]
95 mL of 2,2,3,3-tetrafluoro-1-propanol (TFP) and 1,1,2,2,3,3,4-heptafluorocyclopentane (product) Name: Zeolora H, manufactured by Nippon Zeon Co., Ltd.) was added to a mixed solvent of 5 mL, and ultrasonic waves were applied thereto for 1 hour to dissolve with stirring to prepare a recording layer forming coating solution.
A polycarbonate substrate (outer diameter: 120 mm, inner diameter) on which a spiral pregroove (track pitch: 1.6 μm, pregroove width: 500 nm, pregroove depth: 175 nm) is formed on the surface of this coating solution by injection molding. : Dye recording layer (thickness (inside pregroove): 130 nm) was formed on the surface of the pregroove side of 15 mm and thickness (1.2 mm) by spin coating and drying.
[0055]
Next, silver was sputtered on the dye recording layer using a DC magnetron sputtering apparatus to form a metal reflective layer having a thickness of about 150 nm. Further, a UV curable resin (trade name: Dicure Clear SD-318, manufactured by Dainippon Ink & Chemicals, Inc.) was applied on the metal reflective layer by spin coating, and then irradiated with ultraviolet rays with a metal halide lamp. Curing was performed to form a resin protective layer having a layer thickness of about 8 μm.
[0056]
Through the above steps, a CD-R type optical disc (hereinafter simply referred to as CD-R) according to the present invention in which the substrate, the dye recording layer, the metal reflective layer, and the resin protective layer were laminated in this order was manufactured.
[0057]
[Examples 2 to 5]
In Example 1, in the preparation of the dye recording layer coating solution, 2,2,3,3-tetrafluoro-1-propanol and 1,1,2,2,3,3,4-heptafluorocyclopentane were used. CD-R according to the present invention in the same manner except that the mixing volume ratio is changed as shown in Table 1. (Other than Example 5) Manufactured.
[0058]
[Comparative Example 1]
In Example 1, when preparing the coating solution for the dye recording layer, 100 mL of 2,2,3,3-tetrafluoro-1-propanol was used, and 1,1,2,2,3,3,4-heptafluorocyclopentane was used. A CD-R for comparison was produced in the same manner except that was not used.
[0059]
[Evaluation as an optical information recording medium]
(1) Time required for drying the dye recording layer after coating
In the production of optical disks of Examples and Comparative Examples, a dye recording layer forming coating solution was dropped on a substrate from a spin coater, and the time required until the surface of the dye recording layer after coating was dried was visually measured ( Since the gloss of the coated surface of the dye layer gradually changes toward the outer periphery due to the drying of the surface of the dye recording layer, the change in the gloss was visually observed).
[0060]
(2) Jitter measurement
For the optical disks of Examples and Comparative Examples, an OMT2000 (manufactured by Pulstec) is used, a laser beam with a wavelength of 780 nm is used for a NA0.5 pickup, an EFM signal is recorded at a constant linear velocity of 4.8 m / sec, and the recording power is Recording was performed with the optimum recording power by changing the pressure to 3 to 10 mW. Then, using CD-CATS (produced by Audio Development Co., Ltd.), a recording signal is reproduced with a laser beam having a wavelength of 780 nm and a pickup of NA 0.45 at a constant linear velocity of 1.2 m / sec and a laser power of 0.5 mW. The 11T land jitter (jitter between pits) at a position 40 mm from the center of the substrate was measured using TIA (manufactured by Hewlett Packard). The smaller the jitter value, the more uniform the recording signal. The evaluation results are shown in Table 1.
[0061]
[Table 1]

[0062]
From the results in Table 1, using a coating solution prepared using a mixed solvent of fluorinated alcohol (TFP) and 1,1,2,2,3,3,4-heptafluorocyclopentane (Zeorolla H). In the case of the optical disks according to the present invention (Examples 1 to 5) provided with a dye recording layer, a conventional dye recording layer provided using a coating solution prepared by using a fluorinated alcohol (TFP) solvent alone. It can be seen that the time required for drying the dye recording layer after coating can be shortened as compared with the optical disk (Comparative Example 1). In particular, as seen in Examples 1-4, the mixing volume ratio of fluorinated alcohol and 1,1,2,2,3,3,4-heptafluorocyclopentane is 95: 5 to 60:40. In this case, it can be seen that good jitter is achieved as the time required for drying the dye recording layer after coating is shortened.
[0063]
【The invention's effect】
In the production method according to the present invention, when preparing a coating solution for a dye recording layer of an optical information recording medium, a fluorinated alcohol as a main component and a fluorinated cyclic alkane or alkene (especially 1, 1, 2, 2) are used. , 3,3,4-heptafluorocyclopentane), the drying speed of the dye recording layer after coating is increased compared with the case where a conventional fluorinated alcohol solvent is used alone. be able to. Therefore, the time required for the dye recording layer forming step can be shortened, and productivity can be improved. In addition, fluorinated cyclic alkanes or alkenes (particularly 1,1,2,2,3,3,4-heptafluorocyclopentane) do not dissolve the polycarbonate substrate, and are more pigments than fluorinated alcohol solvents. Although it is poor in solubility, it is possible to prepare a coating solution having good coating characteristics when used in combination with a fluorinated alcohol. Therefore, it is possible to form a uniform dye recording layer and to exhibit good recording / reproducing characteristics. An optical information recording medium can be manufactured. Furthermore, since fluorinated cyclic alkanes or alkenes (especially 1,1,2,2,3,3,4-heptafluorocyclopentane) are available at a lower cost than fluorinated alcohols, the production cost can be reduced. it can.

Claims (9)

  In a method for producing an optical information recording medium including a step of coating and forming a dye recording layer capable of recording information by irradiation with laser light on a transparent disk-shaped substrate, the dye recording layer is formed by fluorinated alcohol and fluorine. A coating solution is prepared by dissolving a dye in a mixed solvent in which a mixed volume of alkane or alkene is mixed so that the mixing volume ratio is in the range of 95: 5 to 60:40, and then the coating solution is applied onto a substrate. A method for producing an optical information recording medium, which is performed by drying. As the fluorinated alcohol, the following general formula (I):
R—CH ₂ OH (I)
[Wherein R represents CF ₃ or H (CF ₂ · CF ₂ ) _n , and n represents an integer of 1 to 3. The method for producing an optical information recording medium according to claim 1, wherein a compound represented by the formula:   The method for producing an optical information recording medium according to claim 2, wherein 2,2,3,3-tetrafluoro-1-propanol is used as the fluorinated alcohol. The method for producing an optical information recording medium according to claim 3 , wherein a solvent having a boiling point lower than that of 2,2,3,3-tetrafluoro-1-propanol is used as the fluorinated cyclic alkane or alkene.   The method for producing an optical information recording medium according to claim 4, wherein a 4- to 6-membered fluorinated cyclic alkane or alkene is used as the fluorinated cyclic alkane or alkene.   6. The method for producing an optical information recording medium according to claim 5, wherein 1,1,2,2,3,3,4-heptafluorocyclopentane is used as the fluorinated cyclic alkane.   A dye solution obtained by dissolving a dye exhibiting a change in physical properties upon irradiation with laser light in a mixed solvent having a mixing volume ratio of fluorinated alcohol and fluorinated cyclic alkane or alkene in the range of 95: 5 to 60:40. The fluorinated alcohol has the following general formula (I):
R—CH ₂ OH (I)
[Wherein R represents CF ₃ or H (CF ₂ · CF ₂ ) _n , and n represents an integer of 1 to 3. The dye solution according to claim 7, wherein the dye solution is represented by the formula:   The dye solution according to claim 7, wherein a 4- to 6-membered fluorinated cyclic alkane or alkene is used as the fluorinated cyclic alkane or alkene.