JP4100991B2 - Optical article using photocurable resin composition, method for forming fine uneven pattern, and transfer foil - Google Patents

Description

【００４４】
（式中、Ｒ¹は水素又は炭素数１〜５のアルキル基を示し、Ｘは単結合又は２価の原子団を示す。）
式（１）中に含まれるＲ¹は、水素又は炭素数１〜５のアルキル基を示し、アルキル基としては、メチル、エチル、ｎ−プロピル、イソプロピル、ｎ−ブチル、イソブチル、ｓｅｃ−ブチル、ｔｅｒｔ−ブチル、ｎ−ペンチル等が例示される。
【００４５】
式（１）中に含まれるＸの構造は特に限定されず、主鎖に水酸基を直接結合させる単結合であっても良いし、何らかの２価の原子団であってもよい。２価の原子団としては、分岐、脂肪族炭素環、芳香族炭素環又は置換基を有していてもよいアルキレン基、或いは、エステル基、アミド基、エーテル基、アルキレンオキシド鎖等の化学構造を含む炭化水素鎖を例示することができる。
【００４６】
２価の原子団Ｘの分子鎖を短くすると架橋が密になるので、樹脂組成物に高硬度が求められる場合に有効であり、逆に、この分子鎖を長くすると、この水酸基の部分にイソシアネート化合物（ｂ）を介して導入した光重合性官能基が動き易くなり、反応性が高くなるので、柔軟で強度のある樹脂が得られる。
【００４７】
式（１）で表される構成単位としては、２価の原子団Ｘがエステル基を含んでいる下記式（１ａ）で表される構成単位が好ましい。２価の原子団Ｘの分子鎖の長さ考慮すると、Ｒ²の炭素原子数は１〜８であることが好ましい。
【００４８】
【化２】

【００４９】
（式中、Ｒ¹は上記式（１）と同じであり、Ｒ²は分岐、脂肪族炭素環、芳香族炭素環又は置換基を有していてもよいアルキレン基である。）
式（１）の構成単位を導入するために使用されるモノマーとしては、２−ヒドロキシエチル（メタ）アクリレート、２−ヒドロキシプロピル（メタ）アクリレート、４−ヒドロキシブチル（メタ）アクリレート、４−ヒドロキシシクロヘキシル（メタ）アクリレート、５−ヒドロキシシクロオクチル（メタ）アクリレート、２−ヒドロキシ−３−フェニルオキシプロピル（メタ）アクリレート等のヒドロキシアルキルアクリレート；Ｎ−メチロール（メタ）アクリルアミド等のヒドロキシル基含有アクリルアミド；ポリエチレングリコール（メタ）アクリレート、ポリプロピレングリコール（メタ）アクリレート；α−ヒドロキシメチルアクリル酸エステル等のα−ヒドロキシアルキルアクリル酸エステル；ビニルアルコール、ビニルフェノール等を例示することができる。
【００５０】
重合体（ａ）の主鎖骨格には、水酸基を有する構成単位が必須単位として含まれるが、主鎖骨格に他の構成単位が含まれていても良い。他の構成単位としては、例えば、アルキル基等の有機基或いはカルボキシル基等の酸性官能基を有する構成単位がある。このような他の構成単位を主鎖骨格に導入するために使用されるモノマーとしてアクリル系化合物やオレフィン系化合物のようなエチレン性不飽和結合を含有する化合物を用いることができる。
【００５１】
アクリル系化合物の具体例としては、（メタ）アクリル酸等のカルボキシル基又はその他の酸性官能基を含有するアクリル系化合物；メチル（メタ）アクリレート、エチル（メタ）アクリレート、ブチル（メタ）アクリレート等のアルキルアクリレート；エトキシエチル（メタ）アクリレート等のアルコキシアルキルアクリレート；２−メトキシエトキシエチル（メタ）アクリレート等のアルコキシアルコキシアルキルアクリレート；メトキシジエチレングリコール（メタ）アクリレート等のアルコキシアルキレングリコールアクリレート；Ｎ，Ｎ−ジメチルアミノエチル（メタ）アクリレート、Ｎ，Ｎ−ジエチルアミノエチル（メタ）アクリレート等のジアルキルアミノアルキル（メタ）アクリレート；その他、アクリロニトリル、ジメチルアクリルアミド、２−イソシアネートエチル（メタ）アクリレート等を挙げることができ、また、（メタ）アクリロイル変性シリコーン、ビニル変性シリコーン等の離型性を有するモノマーも挙げることができる。
【００５２】
また、オレフィン系化合物の具体例としては、２−カルボキシ−１−ブテン、２−カルボキシ−１−ペンテン、２−カルボキシ−１−ヘキセン、２−カルボキシ−１−へプテン等のカルボキシル基又はその他の酸性官能基を含有するオレフィン系化合物を挙げることができる。
【００５３】
特に、嵩高い基を有する構成単位は、その構造自体の耐熱性が高いので、硬化後の樹脂のガラス転移温度を高くするために有効である。嵩高い基を有する構成単位を重合体の主鎖へと導入するために使用されるモノマーとしては、エチレン性不飽和結合含有基と嵩高い基を有するアクリル系化合物が好ましく用いられ、具体的には、シクロヘキシル（メタ）アクリレート、ジシクロペンタニル（メタ）アクリレート、ジシクロペンテニル（メタ）アクリレート、ジシクロペンテニルオキシエチル（メタ）アクリレート、イソボルニル（メタ）アクリレート、ベンジル（メタ）アクリレート、フェニル（メタ）アクリレート、アクリロイルモルフォリン、アダマンチル（メタ）アクリレート、３−ヒドロキシアダマンチル（メタ）アクリレート、スチレン、α−メチルスチレン、４−ビニルピリジン、ビニルピロリドン、ビニルカプロラクトン等の環状構造を有するモノマーを例示することができる。
【００５４】
また、Ｎ−フェニルマレイミド等の光二量化反応を起こす官能基を有するモノマー、グリシジル（メタ）アクリレート等の光カチオン重合を起こす官能基を有するモノマーを、構成単位として用いることができる。
【００５５】
水酸基を有する構成単位や嵩高い基を有する構成単位、及びその他の構成単位を形成する共重合モノマーは、各々例示したものを単独でも、また２種以上を混合して使用しても良い。
【００５６】
重合体（ａ）中に含まれる水酸基を有する構成単位の量は、要求される光重合性の程度に応えるべく調節され、重合体の主鎖を形成するための共重合モノマーの総使用量（総仕込み量）に対する水酸基含有モノマーの仕込み量の割合で表す時に、通常は５〜９０モル％、特に１０〜６０モル％含有することが好ましい。水酸基を有する構成単位の割合が少なすぎる場合には、最終的に光硬化性樹脂に導入される光重合性官能基の量が少なくなるために架橋密度が不充分となり易く、さらには光重合性官能基の導入に伴い形成されるウレタン結合構造の量も少なくなるため、当該光硬化性樹脂は硬化前の熱可塑性及び硬化後の柔軟性が不充分となり易い。一方、水酸基を有する構成単位の割合が多すぎる場合には、合成時にゲル化する等の不都合がある。
【００５７】
嵩高い基を有する構成単位は、主に、光硬化性樹脂の硬化前の熱可塑性及び硬化後の柔軟性を考慮して調節され、重合体の主鎖を形成するための共重合モノマーの総使用量（総仕込み量）に対する嵩高い基を含有するモノマーの仕込み量の割合で表す時に、通常は０〜９０モル％、特に５〜８０モル％含有することが好ましい。嵩高い基を有する構成単位の割合が少なすぎる場合には、最終的に得られる光硬化性樹脂の硬化前の耐ブロッキング性及び硬化後の耐熱性が不充分となり易い。一方、嵩高い基を有する構成単位の割合が多すぎる場合には、最終的に得られる光硬化性樹脂の硬化前の熱可塑性が低下するという不都合がある。
【００５８】
上記重合体（ａ）としては、例えば下記式（２）
【００５９】
【化３】

【００６０】
（式中、Ｚは光硬化性樹脂を改質するための基を表し、好ましくは嵩高い環状構造の基である。Ｒ³は夫々互いに独立して水素原子又はメチル基を表し、Ｒ⁴は炭素数１〜２０の炭化水素基を表し、Ｒ⁵は直鎖状又は分岐鎖状のアルキレン基を表す。ｌ（エル）とｍとｎとｏ（オー）の合計を１００とした場合に、ｌは０〜９０、ｍは０〜８０、ｎは０〜５０、ｏは５〜９０の整数である。）
で表される構造の重合体を例示することができる。
【００６１】
この式（２）で表される重合体の中で好ましい１例としては、メチルメタクリレート０〜９０モルと、嵩高い基を有するビニル系又はアクリル系モノマー（例えばイソボルニルメタクリレート）０〜８０モルとメタクリル酸０〜５０モルと２−ヒドロキシエチルメタクリレート１０〜８０モルとを共重合して得られるものを例示することができる。
【００６２】
前記イソシアネート化合物（ｂ）とは、一分子内に少なくとも２つのイソシアネート基を有して前記重合体（ａ）及び前記重合性化合物（ｃ）の各々の水酸基とウレタン結合することができるイソシアネート化合物をいい、そのようなイソシアネート化合物としては、テトラメチレンジイソシアネート、ヘキサメチレンジイソシアネート、２，４−トリレンジイソシアネート、２，６−トリレンジイソシアネート、４，４’−ジフェニルメタンジイソシアネート、１，５−ナフタレンジイソシアネート、３，３−ジメチル−４，４−ジフェニレンイソシアネート、イソホロンジイソシアネート、ｍ−キシリレンジイソシアネート、ｐ−キシリレンジイソシアネート、１，３−ビス（イソシアネートメチル）シクロヘキサン、１，３−ビス（α，α−ジメチルイソシアネートメチル）ベンゼン、トリメチルヘキサメチレンジイソシアネート、水素添加キシリレンジイソシアネート等が挙げられる。
【００６３】
また、下記式（３ａ）乃至（３ｇ）で表されるイソシアネート化合物を使用することもできる。
【００６４】
【化４】

【化５】

【００６５】
これらのイソシアネート化合物は、単独で又は２種以上を混合して使用することができる。これらの中でも、イソホロンジイソシアネートは下記式（４）で表される化合物であり、樹脂の柔軟性や隣接する層との密着性の観点から好ましく用いられる。
【００６６】
【化６】

【００６７】
前記重合性化合物（ｃ）は、前記重合体（ａ）に導入すべき１又は２以上の光重合性官能基、及び、前記イソシアネート化合物（ｂ）のイソシアネート基とウレタン結合を形成するための水酸基を有する化合物である。
【００６８】
重合性化合物（ｃ）における光重合性官能基とは、光照射により重合反応し、光硬化性樹脂の分子間に架橋結合を形成し得る官能基であり、光照射により直接活性化して光重合反応するものであってもよいし、光重合性官能基と光重合開始剤を共存させて光照射した時に光重合開始剤から発生した活性種の作用により重合反応が開始、促進されるものであってもよい。なお本発明において光には、可視及び非可視領域の波長の電磁波だけでなく、放射線も含まれ、放射線には、例えばマイクロ波、電子線が含まれる。
【００６９】
光重合性官能基としては、例えば、エチレン性不飽和結合（代表的にはエチレン性二重結合）のような光ラジカル重合反応性を有するもの、エポキシ基等の環状エーテル基のような光カチオン重合反応性を有するもの、光アニオン重合反応性を有するもの、及び、光二量化反応性を有するもの等が該当する。その中でもエチレン性二重結合が好ましい。エチレン性二重結合は、（メタ）アクリロイル基、ビニル基、アリル基等のいずれでもよく、中でも（メタ）アクリロイル基が好ましい。
【００７０】
水酸基と共に（メタ）アクリロイル基を有する化合物としては、例えば、２−ヒドロキシエチル（メタ）アクリレート、２−ヒドロキシプロピル（メタ）アクリレート、４−ヒドロキシシクロヘキシル（メタ）アクリレート、５−ヒドロキシシクロオクチル（メタ）アクリレート、２−ヒドロキシ−３−フェニルオキシプロピル（メタ）アクリレートのような（メタ）アクリロイル基を１つのみ有する化合物；及び、トリメチロールプロパンジアクリレート、ペンタエリスリトールトリアクリレート、ジペンタエリスリトールモノヒドロキシペンタアクリレート、イソシアヌル酸オキシエチルジ（メタ）アクリレート、グリセロール（メタ）アクリレート類、ポリエチレングリコール（メタ）アクリレート類のような（メタ）アクリロイル基を２つ以上有する化合物が例示できる。
【００７１】
これらの中でも、（メタ）アクリロイル基を２つ以上有する化合物は、重合体（ａ）に含まれる個々の水酸基に対して複数の（メタ）アクリロイル基を導入できるので、光硬化性樹脂の架橋密度を充分に高めることができ、好ましい。
【００７２】
本発明に係る光硬化性樹脂を製造する際に、重合体（ａ）、イソシアネート化合物（ｂ）及び重合性化合物（ｃ）を一度に混合して反応させると、イソシアネート化合物（ｂ）の一分子内に複数存在する全てのイソシアネート基が、重合体（ａ）とだけ又は重合性化合物（ｃ）とだけ反応する副反応が起こり易いので、上記した通りの分子構造を得ることが難しい。そのため、本発明に係る光硬化性樹脂を製造するためには、先ず、水酸基を有する構成単位を主鎖骨格に含む重合体（ａ）、及び、イソシアネート化合物（ｂ）と重合性化合物（ｃ）の付加物（ｂ−ｃ）とを各々別個に製造し、それから前記重合体（ａ）に付加物（ｂ−ｃ）を反応させることが好ましい。
【００７３】
前記重合体（ａ）を製造するために用いられる重合用溶媒としては、水酸基、アミノ基等の活性水素を有しない溶媒が好ましく、例えば、テトラヒドロフラン等のエーテル類；ジエチレングリコールジメチルエーテル、ジエチレングリコールジエチルエーテル、ジエチレングリコールメチルエチルエーテル等のグリコールエーテル類、メチルセロソルブアセテート等のセロソルブエステル類やプロピレングリコールモノメチルエーテルアセテート、酢酸−３−メトキシブチル等が挙げられ、芳香族炭化水素類、ケトン類、エステル類等も用いることができる。
【００７４】
重合体（ａ）を製造するために用いられる重合開始剤としては、一般的にラジカル重合開始剤として知られているものを使用することができる。その具体例としては、２，２’−アゾビスイソブチロニトリル、２，２’−アゾビス−（２，４−ジメチルバレロニトリル）、２，２’−アゾビス−（４−メトキシ−２，４−ジメチルバレロニトリル）等のニトリル系アゾ化合物（ニトリル系アゾ系重合開始剤）；ジメチル２，２’−アゾビス（２−メチルプロピオネート）、２，２’−アゾビス（２，４，４−トリメチルペンタン）等の非ニトリル系アゾ化合物（非ニトリル系アゾ系重合開始剤）；ｔ−ヘキシルペルオキシピバレート、ｔｅｒｔ−ブチルペルオキシピバレート、３，５，５−トリメチルヘキサノイルペルオキシド、オクタノイルペルオキシド、ラウロイルペルオキシド、ステアロイルペルオキシド、１，１，３，３−テトラメチルブチルペルオキシ−２−エチルヘキサノエート、サクシニックペルオキシド、２，５−ジメチル−２，５−ジ（２−エチルヘキサノイルペルオキシ）ヘキサン、１−シクロヘキシル−１−メチルエチルペルオキシ２−エチルヘキサノエート、ｔ−ヘキシルペルオキシ−２−エチルヘキサノエート、４−メチルベンゾイルペルオキシド、ベンゾイルペルオキシド、１，１’−ビス−（ｔｅｒｔ−ブチルペルオキシ）シクロヘキサン等の有機過酸化物（パーオキサイド系重合開始剤）；および過酸化水素が挙げられる。ラジカル重合開始剤として過酸化物を使用する場合には、これと還元剤とを組み合わせてレドックス型重合開始剤として使用してもよい。
【００７５】
重合体（ａ）の製造においては、重量平均分子量を調節するために分子量調節剤を使用することができ、例えば、クロロホルム、四臭化炭素等のハロゲン化炭化水素類；ｎ−ヘキシルメルカプタン、ｎ−オクチルメルカプタン、ｎ−ドデシルメルカプタン、ｔｅｒｔ−ドデシルメルカプタン、チオグリコール酸等のメルカプタン類；ジメチルキサントゲンジスルフィド、ジイソプロピルキサントゲンジスルフィド等のキサントゲン類；ターピノーレン、α−メチルスチレンダイマー等が挙げられる。
【００７６】
重合体（ａ）は、ランダム共重合体およびブロック共重合体のいずれであってよい。ランダム共重合体を製造する場合には、前記の各モノマー、触媒からなる配合組成物を、溶剤を入れた重合槽中に８０〜１１０℃の温度条件で２〜５時間かけて滴下し、熟成させることにより重合させることが可能であり、重合体（ａ）が得られる。
【００７７】
イソシアネート化合物（ｂ）と重合性化合物（ｃ）とを反応させて得られる付加物（ｂ−ｃ）は、その分子内に、重合体（ａ）の水酸基と反応してウレタン結合を形成し得るイソシアネート基が１つ残っていれば充分である。従って、イソシアネート化合物（ｂ）としてジイソシアネート化合物を用い、重合性化合物（ｃ）として分子内に水酸基を１つだけ有する化合物を用いる場合には、イソシアネート化合物（ｂ）と重合性化合物（ｃ）の仕込み量を等モル前後とし、約１：１モルの付加物を調製することが好ましい。
【００７８】
イソシアネート化合物（ｂ）に対する重合性化合物（ｃ）の付加量が多すぎる場合にはイソシアネート基が消費され過ぎてしまうので、重合体（ａ）の水酸基と反応できない副生物が増加するという不都合がある。一方、イソシアネート化合物（ｂ）に対する重合性化合物（ｃ）の付加量が少な過ぎる場合には付加物（ｂ−ｃ）の収率が下がるという不都合がある。
【００７９】
前記重合体（ａ）と付加物（ｂ−ｃ）との反応は、前記重合体（ａ）を溶解可能な溶剤、例えば、トルエン、ケトン、セロソルブアセテート、ジメチルスルフォキサイド等の溶媒に溶解させ、この溶液を撹拌しながら、付加物（ｂ−ｃ）を滴下及び反応させることにより、付加物（ｂ−ｃ）中のイソシアネート基が重合体（ａ）の水酸基と反応してウレタン結合を生じ、該ウレタン結合及び付加物（ｂ−ｃ）中のウレタン結合を介して重合体（ａ）中に光重合性官能基を導入することができる。この際に使用する付加物（ｂ−ｃ）の使用量は、重合体（ａ）の水酸基を有する構成単位と付加物（ｂ−ｃ）との比率で、水酸基を有する構成単位１モル当たり付加物（ｂ−ｃ）が０．１〜１０モル、好ましくは０．５〜５モルの範囲になる量である。尚、上記重合体（ａ）中の水酸基よりも当量以上の付加物（ｂ−ｃ）を使用する場合で重合体（ａ）にカルボキシル基が含まれる場合には、該付加物（ｂ−ｃ）は重合体（ａ）中のカルボキシル基とも反応してアミド結合を生じることもあり得る。
【００８０】
本発明においては、重合体（ａ）の水酸基に対し付加物（ｂ−ｃ）が全てウレタン結合して光硬化性樹脂を形成し、且つ、重合体（ａ）の水酸基に結合していない付加物（ｂ−ｃ）や重合性化合物（ｃ）が反応生成物中に混在していないことが好ましいが、これらの付加物（ｂ−ｃ）や重合性化合物（ｃ）は、光重合性官能基を複数有するモノマーとして機能し、本発明に係る光硬化性樹脂との間で架橋結合を形成し得るので、ある程度の量であれば光硬化性樹脂と共存していてもよく、硬化時に架橋密度を高めて硬化樹脂層の塗膜物性を向上させる効果が得られる。従って、重合体（ａ）に付加物（ｂ−ｃ）を反応させる方法で得られる光硬化性樹脂は、副生物又は未反応体による悪影響が少ないため、これらが混在したままの状態でも凹凸パターン形成材料として利用可能であり、精製の手間が省ける点で有利である。
【００８１】
本発明に係る光硬化性樹脂は、ポリスチレン換算重量平均分子量が１０，０００〜５００，０００であることが好ましい。上記分子量が１０，０００未満の場合には、充分な成膜性が得られないばかりでなく、塗工後に室温で巻取り保管した時にブロッキングを起こし易い。また、上記分子量が５００，０００を超える場合には軟化しにくいために賦型性が悪くなる。
【００８２】
次に、本発明に係る光硬化性樹脂組成物について説明する。本発明に係る光硬化性樹脂組成物は、上記本発明に係る光硬化性樹脂と、離型剤とを必須成分として含有する。
【００８３】
本発明に係る光硬化性樹脂組成物に含有される光硬化性樹脂は、上述したように硬化前には優れた凹凸パターン形成能と加工適性を発揮すると共に、硬化後には優れた塗膜物性を発揮する。そのため本発明に係る光硬化性樹脂組成物は、非常に複雑な微細凹凸パターンでも精度良く複製することができ、複製の際に連続生産性にも優れ、さらには、強度、硬度、耐熱性、耐擦傷性、耐水性、耐薬品性、被塗布面（代表的には基材）に対する密着性、基材の屈曲や伸縮に追随できる可とう性等の諸物性に優れた微細凹凸パターン形成層を形成することができる。
【００８４】
特に、重合性化合物（ｃ）として一分子内に光重合性官能基を２つ以上有するものを用いる場合には、上記したように光硬化性樹脂に多量の光重合性官能基が導入されるので、光硬化性樹脂組成物の架橋密度が非常に大きくなり、硬化後の諸物性を向上させる効果が高い。
【００８５】
硬化後の諸物性の中でも、とりわけ耐熱性及び耐久性（耐摩耗性、耐薬品性、耐水性）が架橋密度の増大によって向上し、高熱、摩擦又は溶剤に曝されても、微細凹凸パターンの変形、消失、損傷が起こり難い。
【００８６】
また、本発明に係る光硬化性樹脂組成物は、優れた離型性を有する上記光硬化性樹脂に対し離型剤を必須成分として配合することにより、さらに離型性を改善しているので、光硬化性樹脂組成物の層に押し付けたスタンパーを、樹脂層の面荒れや版取られを起こさずにきれいに剥離することができ、且つ、剥離の際にスタンパー内に樹脂の一部が残らないので反復エンボス性にも優れており、微細凹凸パターンの精度及び連続生産性の点で特に優れている。
【００８７】
離型剤としては従来公知の離型剤、例えば、シリコーン系離型剤、ポリエチレンワックス、アミドワックス、テフロンパウダー（テフロンは登録商標）等の固形ワックス、弗素系、リン酸エステル系の界面活性剤等が何れも使用可能である。
【００８８】
シリコーン系離型剤は、本発明で用いられる上記光硬化性樹脂と組み合わせた時にスタンパーからの離型性が特に良好であり、版取られ現象が起こり難くなる。シリコーン系離型剤は、オルガノポリシロキサン構造を基本構造とする離型剤であり、例えば、未変性又は変性シリコーンオイル、トリメチルシロキシケイ酸を含有するポリシロキサン、シリコーン系アクリル樹脂等が該当する。
【００８９】
変性シリコーンオイルは、ポリシロキサンの側鎖及び／又は末端を変性したものであり、反応性シリコーンオイルと非反応性シリコーンオイルとに分けられる。反応性シリコーンオイルとしては、アミノ変性、エポキシ変性、カルボキシル変性、カルビノール変性、メタクリル変性、メルカプト変性、フェノール変性、片末端反応性、異種官能基変性等が挙げられる。非反応性シリコーンオイルとしては、ポリエーテル変性、メチルスチリル変性、アルキル変性、高級脂肪エステル変性、親水性特殊変性、高級アルコキシ変性、高級脂肪酸変性、フッ素変性等が挙げられる。一つのポリシロキサン分子に上記したような変性方法の２つ以上を行うこともできる。
【００９０】
変性シリコーンオイルは樹脂との適度な相溶性があるため好ましい。特に、光硬化性樹脂又は光硬化性樹脂組成物中に必要に応じて配合される他の塗膜形成成分に対して反応性がある反応性シリコーンオイルを用いる場合には、硬化樹脂層中に化学結合よって固定されるので、当該硬化樹脂層の密着性阻害、汚染、劣化等の問題が起き難い。特に、蒸着工程での蒸着層との密着性向上には有効である。また、（メタ）アクリロイル変性シリコーン、ビニル変性シリコーン等の、光硬化性を有する官能基で変性されたシリコーンの場合は、本発明の光硬化性樹脂組成物と架橋するため、硬化後の特性に優れる。
【００９１】
トリメチルシロキシケイ酸を含有するポリシロキサンは表面にブリードアウトし易く離型性に優れており、表面にブリードアウトしても樹脂との密着性に優れ、金属蒸着やオーバーコート層との密着性にも優れている点で好ましい。
【００９２】
シリコーン系アクリル樹脂は、上記（メタ）アクリロイル変性シリコーンオイルの他にも、ケイ素を含有するモノマーを共重合或いはグラフト化したアクリル樹脂を用いることができる。
【００９３】
上記離型剤は１種類のみ或いは２種類以上を組み合わせて添加することができる。
【００９４】
離型剤は、光硬化性樹脂組成物の固形分全量中に０．１〜３０重量％の割合で配合するのが好ましい。離型剤の割合が上記範囲未満では、スタンパーと光硬化性樹脂層の離型性が不充分となりやすい。一方、離型剤の割合が上記範囲を超えると組成物の塗工時のはじきによる塗膜面の面荒れの問題が生じたり、製品において基材自身及び近接する層、例えば、蒸着層の密着性を阻害したり、転写時に皮膜破壊等（膜強度が弱くなりすぎる）を引き起こす等の点で好ましくない。
【００９５】
本発明に係る光硬化性樹脂組成物に、有機溶媒にコロイド状に分散させることが可能な無機微粒子を含有させる場合には、賦型性、形状維持性及び離型性が向上する点から好ましい。
【００９６】
有機溶媒にコロイド状に分散させることが可能な無機微粒子としては、無機微粒子の一部が水酸化物になっており水が吸着して水和した構造をとっていると、光硬化性樹脂組成物の希釈溶剤である有機溶媒中でコロイド状の形態に分散させやすいので好ましい。また、無機微粒子の表面を疎水化処理すると、コロイド状に分散させやすくなる。無機微粒子は、例えば、有機アミンや有機カルボン酸などの有機低分子成分で表面処理することにより疎水性を付与することができる。
【００９７】
また、無機微粒子は、塗膜に充分な透明性を確保するために、いわゆる超微粒子サイズのものを用いる。ここで「超微粒子」とはサブミクロンオーダーの粒子のことであり、一般的に「微粒子」と呼ばれている数μｍから数１００μｍの粒子径を有する粒子よりも粒子径の小さいものを意味している。本発明において用いられる無機微粒子の具体的なサイズは、光硬化性樹脂組成物が適用される光学物品の用途及びグレードによっても相違するが、一般的には一次粒子径が１ｎｍ〜３００ｎｍの範囲のものを用いるのが好ましい。一次粒子径が１ｎｍ未満では、樹脂組成物の賦型性、形状維持性及び離型性を充分に向上させることが困難になり、一方、一次粒子径が３００ｎｍを超えると、樹脂の透明性が損なわれ光学用物品の用途によっては透明性が不充分となる場合がある。
【００９８】
無機微粒子の具体例としては、ＳｉＯ₂、ＴｉＯ₂、ＺｒＯ₂、ＳｎＯ₂、Ａｌ₂Ｏ₃等の金属酸化物微粒子を挙げることができ、これらの中から上記したようにコロイド状分散が可能で且つサブミクロンオーダーの粒子サイズを有するものを選択して用いるのが好ましく、特に、コロイダルシリカ（ＳｉＯ₂）微粒子を用いるのが好ましい。
【００９９】
無機微粒子は、光硬化性樹脂組成物の固形分全量中に１〜７０重量％の割合で配合するのが好ましく、１〜５０重量％の割合で配合するのが特に好ましい。無機微粒子の割合が１重量％未満では、樹脂組成物の賦型性、形状維持性及び離型性を充分に向上させることが困難になり、一方、無機微粒子の割合が７０重量％を超えると、脆質性が顕著になり、露光硬化後に充分な強度や表面硬度が得られにくくなる。
【０１００】
無機微粒子は、どのような形状であってもよいが、針状等の嵩高い形状のものが好ましい。針状微粒子としては、例えば、太さが５〜２０ｎｍで、長さが４０〜３００ｎｍのものを用いることができる。
【０１０１】
無機微粒子の表面に（メタ）アクリロイル基等の反応性官能基を導入し、これを用いる場合には、微粒子同士で又は光硬化性樹脂の硬化性成分との間で共有結合等の化学結合を形成させることができるので、塗膜の諸物性、特に強度及び硬度が向上する。
【０１０２】
このような無機微粒子を光硬化性樹脂組成物に配合する場合には、当該光硬化性樹脂組成物からなる光硬化性樹脂層にプレススタンパーを押圧して微細凹凸パターンを賦形し、スタンパーを取り外した後の露光工程や蒸着工程等のプロセス途中で、樹脂組成物自身の弾性により微細凹凸パターンが丸みを帯びて型崩れするのを防ぐことができる。また、上記無機微粒子を配合することにより光硬化性樹脂組成物の離型性が向上し、光硬化性樹脂層に押圧したスタンパーを取り外すときにスタンパーのキャビティ内面に樹脂組成物が付着しにくくなる。
【０１０３】
これにより、従来から要求されている程度の凹凸の幅（ピッチ）が約１０μｍ以下又は凹凸の深さが２μｍ以下の微細凹凸パターンを精度良く複製できることは言うまでもなく、より高度な光学的機能を有する複雑な微細凹凸パターン、例えば、凹凸パターンの幅（ピッチ）が約２００ｎｍ以下であったり、或いは、幅に対する深さ（深さ／幅）が１／２以上であるパターンを複製する場合でも、スタンパーの圧接時にキャビティ内の隅々にまで微細凹凸パターン形成材料を流し込むことができ、スタンパーを引き剥がす時に版取られを起こさず、スタンパーを取り除いた後のパターン崩れも起こし難いため、微細凹凸パターンを精度良く且つエンボス加工により大量連続生産することが可能になる。
【０１０４】
さらには、無機微粒子には光硬化性樹脂組成物のタック性を軽減する効果もあり、基材フィルムに光硬化性樹脂層を形成しプレススタンパーを押圧する前の中間積層体をロール状に巻き取ってもブロッキングを生じにくくなるという利点がある。
【０１０５】
本発明の光硬化性樹脂組成物には、光硬化性樹脂組成物の硬化前又は硬化後の物性を調節する目的で、補助的なバインダー成分、例えば、非反応性又は架橋反応性のバインダーポリマー、或いは、単官能又は多官能の光重合性モノマー又はオリゴマーを配合しても良い。架橋反応性のバインダー成分を補助的に用いる場合には、通常、上記光硬化性樹脂と同じ反応形式のものが用いられ、例えば、光硬化性樹脂が光ラジカル重合性であれば、補助的バインダー成分も光ラジカル重合性のものが組み合わされる。
【０１０６】
多官能のモノマー又は多官能オリゴマー、すなわち光重合性官能基を一分子内に２つ以上有するモノマー又はオリゴマーは、光硬化性樹脂組成物の架橋密度をさらに高める目的で好適に用いられる。
【０１０７】
光ラジカル重合性を有する２官能のモノマー、オリゴマーとしてはポリエチレングリコールジ（メタ）アクリレート、ポリプロピレングリコールジ（メタ）アクリレート、ネオペンチルグリコールジ（メタ）アクリレート、１，６−ヘキサンジオールジ（メタ）アクリレート等；３官能のモノマー、オリゴマーとしてはトリメチロールプロパントリ（メタ）アクリレート、ペンタエリスリトールトリ（メタ）アクリレート、脂肪族トリ（メタ）アクリレート等；４官能のモノマー、オリゴマーとしてはペンタエリスリトールテトラ（メタ）アクリレート、ジトリメチロールプロパンテトラ（メタ）アクリレート、脂肪族テトラ（メタ）アクリレート等が挙げられる。５官能以上の光ラジカル重合性モノマー、オリゴマーとしてはジペンタエリスリトールペンタ（メタ）アクリレート、ジペンタエリスリトールヘキサ（メタ）アクリレート等；その他にも、ポリエステルアクリレート、ウレタンアクリレート、ポリエーテルアクリレート、エポキシアクリレート等の各種アクリレートオリゴマー；フォスファゼン骨格、アダマンタン骨格、カルド骨格、ノルボルネン骨格等の嵩高い構造を持つモノマー又はオリゴマー等が挙げられる。官能基数は特に限定されるものではないが、官能基数が３より小さいと耐熱性が低下する傾向があり、又、２０以上では柔軟性が低下する傾向があるため、特に３〜２０官能のものが好ましい。
【０１０８】
多官能の光ラジカル重合性モノマー又はオリゴマーとしては、上記の（メタ）アクリレート類のほか、ジビニルベンゼン等のビニル化合物、ジエチレングリコールビスアリルカーボネート、トリメチロールプロパンジアリル、ジアリルフタレート、ジメタクリルフタレート、ジアリルイソフタレート等のアリル化合物を用いることもできる。
【０１０９】
光カチオン重合反応を利用する場合には、分子内に一つ以上のエポキシ基を有するモノマー、分子内に一つ以上のエポキシ基と一つ以上の（メタ）アクリロイル基を有するモノマー、オキセタン化合物等を使用することができる。
【０１１０】
上記モノマー或いはオリゴマーの使用量は、前記光硬化性樹脂１００重量部当たり約５〜８０重量部の範囲、好ましくは約１０〜４０重量部の範囲で使用する。モノマー或いはオリゴマーの使用量が上記範囲未満では、得られる硬化樹脂層の強度、耐熱性、耐擦傷性、耐水性、耐薬品性、基材に対する密着性を向上させるためには充分でない場合が多い。一方、モノマー或いはオリゴマーの使用量が上記範囲を超えると表面のタックが高くなり、ブロッキングを引き起こしたり、ホログラム等の複製時に版（プレススタンパー）に材料が一部残る（版取られ）ことにより反復エンボス性が低下する等の問題を来たし易い。
【０１１１】
本発明に係る光硬化性樹脂組成物には、必要に応じてさらに光重合開始剤、重合禁止剤や、有機金属カップリング剤等の他の成分を配合して調製することができる。
【０１１２】
光重合開始剤は、使用する光源の波長に対して活性を有するものが配合され、バインダーやモノマーの反応形式の違い（例えばラジカル重合やカチオン重合など）に応じて適切な活性種を発生させるものを用いる。
【０１１３】
光ラジカル開始剤としては、例えば、ベンゾイン、ベンゾインメチルエーテル、ベンゾインエチルエーテル、ベンゾインイソプロピルエーテル、α−メチルベンゾイン、α−フェニルベンゾイン、アントラキノン、メチルアントラキノン、アセトフェノン、２，２−ジエトキシアセトフェノン、２，２−ジメトキシ−２−フェニルアセトン、ベンジルジアセチルアセトフェノン、ベンゾフェノン、ｐ−クロロベンゾフェノン、２−ヒドロキシ−２−メチルプロピオフェノン、ジフェニルジスルフィド、テトラメチルチウラムスルフィド、α−クロルメチルナフタレン、アントラセン、ヘキサクロロブタジエン、ペンタクロロブタジエン、ミヒラーズケトン、２−クロロチオキサントン、２，４−ジエチルチオキサントン、ベンジルジメチルケタール、ビス（２，４，６−トリメチルベンゾイル）−フェニルフォスフィンオキサイド、２−メチル−１−［４−（メチルチオ）フェニル］−２−モルフォリノプロパノン−１，２−ヒドロキシ−２−メチル−１−フェニルプロパン−１−オン、１−［４−（２−ヒドロキシエトキシ）−フェニル］−２−ヒドロキシ−２−メチル−１−プロパン−１−オン等がある。
【０１１４】
光カチオン開始剤としては、例えば、芳香族ジアゾニウム塩、芳香族ヨードニウム塩、芳香族スルホニウム塩、芳香族ホスホニウム塩、混合配位子金属塩等が挙げられる。
【０１１５】
光アニオン開始剤としては、例えば、１,１０‐ジアミノデカンや４,４’‐トリメチレンジピペリジン、カルバメート類及びその誘導体、コバルト‐アミン錯体類、アミノオキシイミノ類、アンモニウムボレート類等を例示することができる。
【０１１６】
上記光重合開始剤は、光硬化性樹脂組成物の固形分全量に対して０．５〜１０重量％の割合で配合するのが好ましい。光重合開始剤は１種のみを単独で用いてもよいし、２種以上を組み合わせて用いてもよい。
【０１１７】
本発明の光硬化性樹脂組成物には、貯蔵安定性を向上させるために、重合禁止剤を配合してもよい。重合禁止剤としては、例えば、ハイドロキノン、ｔ−ブチルハイドロキノン、カテコール、ハイドロキノンモノメチルエーテル等のフェノール類；ベンゾキノン、ジフェニルベンゾキノン等のキノン類；フェノチアジン類；銅類等を用いることができる。重合禁止剤は、光硬化性樹脂組成物の固形分全量に対して０．１〜１０重量％の割合で配合するのが好ましい。
【０１１８】
光硬化性樹脂組成物には、微細凹凸パターンを有する表面構造の耐熱性、強度、或いは、金属蒸着層との密着性を高めるために、有機金属カップリング剤を配合してもよい。また、有機金属カップリング剤は、熱硬化反応を促進させる効果も持つため有効である。有機金属カップリング剤としては、例えば、シランカップリング剤、チタンカップリング剤、ジルコニウムカップリング剤、アルミニウムカップリング剤、スズカップリング剤等の各種カップリング剤を使用できる。
【０１１９】
シランカップリング剤としては、例えば、ビニルトリクロルシラン、ビニルトリス（β−メトキシエトキシ）シラン、ビニルトリエトキシシラン、ビニルトリメトキシシラン等のビニルシラン；γ−メタクリロキシプロピルトリメトキシシラン、γ−メタクリロキシプロピルメチルジメトキシシラン等のアクリルシラン；β−（３，４−エポキシシクロヘキシル）エチルトリメトキシシラン、γ−グリシドキシプロピルトリメトキシシラン、γ−グリシドキシプロピルメチルジエトキシシラン等のエポキシシラン；Ｎ−β−（アミノエチル）−γ−アミノプロピルトリメトキシシラン、Ｎ−β−（アミノエチル）−γ−アミノプロピルメチルジメトキシシラン、γ−アミノプロピルトリメトキシシラン、Ｎ−フェニル−γ−アミノプロピルトリメトキシシラン等のアミノシラン；及び、その他のシランカップリング剤として、γ−メルカプトプロピルトリメトキシシラン、γ−クロロプロピルメチルジメトキシシラン、γ−クロロプロピルメチルジエトキシシラン等が挙げられる。
【０１２０】
チタンカップリング剤としては、例えば、イソプロピルトリイソステアロイルチタネート、イソプロピルトリドデシルベンゼンスルホニルチタネート、イソプロピルトリス（ジオクチルパイロホスフェート）チタネート、テトライソプロピルビス（ジオクチルホスファイト）チタネート、テトラオクチルビス（ジトリデシルホスファイト）チタネート、テトラ（２，２−ジアリルオキシメチル）ビス（ジトリデシル）ホスファイトチタネート、ビス（ジオクチルパイロホスフェート）オキシアセテートチタネート、ビス（ジオクチルパイロホスフェート）エチレンチタネート、イソプロピルトリオクタノイルチタネート、イソプロピルジメタクリルイソステアロイルチタネート、イソプロピルイソステアロイルジアクリルチタネート、イソプロピルトリ（ジオクチルホスフェート）チタネート、イソプロピルトリクミルフェニルチタネート、イソプロピルトリ（Ｎ−アミノエチル・アミノエチル）チタネート、ジクミルフェニルオキシアセテートチタネート、ジイソステアロイルエチレンチタネート等が挙げられる。
【０１２１】
ジルコニウムカップリング剤としては、例えば、テトラ−ｎ−プロポキシジルコニウム、テトラ−ブトキシジルコニウム、ジルコニウムテトラアセチルアセトネート、ジルコニウムジブトキシビス（アセチルアセトネート）、ジルコニウムトリブトキシエチルアセトアセテート、ジルコニウムブトキシアセチルアセトネートビス（エチルアセトアセテート）等が挙げられる。
【０１２２】
アルミニウムカップリング剤としては、例えば、アルミニウムイソプロピレート、モノｓｅｃ−ブトキシアルミニウムジイソプロピレート、アルミニウムｓｅｃ−ブチレート、アルミニウムエチレート、エチルアセトアセテエートアルミニウムジイソプロピレート、アルミニウムトリス（エチルアセトアセテート）、アルキルアセトアセテートアルミニウムジイソプロピレート、アルミニウムモノアセチルアセトネートビス（エチルアセトアセテート）、アルミニウムトリス（アセチルアセトアセテート）等を挙げることができる。
【０１２３】
上記有機金属カップリング剤は、光硬化性樹脂組成物の固形分全量中に０．１〜１５重量％の割合で配合するのが好ましい。有機金属カップリング剤の割合が上記範囲未満では、耐熱性、強度、蒸着層との密着性の付与効果が不充分である。一方、有機金属カップリング剤の割合が上記範囲を超えると、組成物の安定性、成膜性が損なわれるおそれがある。
【０１２４】
本発明の光硬化性樹脂組成物は、通常、希釈溶剤を用いて塗布液の状態に調製し、微細凹凸パターンの形成に用いる。上記したような各材料を、アセトン、メチルエチルケトン、メチルイソブチルケトン、シクロヘキサノン、ベンゼン、トルエン、キシレン、クロルベンゼン、テトラヒドロフラン、メチルセロソルブ、エチルセロソルブ、メチルセロソルブアセテート、エチルセロソルブアセテート、酢酸エチル、１，４−ジオキサン、１，２−ジクロロエタン、ジクロルメタン、クロロホルム、メタノール、エタノール、イソプロパノール等、またはそれらの混合溶剤に溶解、分散することにより、本発明に係る光硬化性樹脂組成物の塗布液を調製することができる。塗布液は、通常、固形分濃度が１０〜５０重量％程度となるように調節される。
【０１２５】
なお、光硬化性樹脂組成物を調製する際に、重合体（ａ）に付加物（ｂ−ｃ）を反応させる方法で得られた光硬化性樹脂を用いる場合には、上述したように副生物又は未反応体による悪影響が少ないため、重合体（ａ）に付加物（ｂ−ｃ）を反応させた反応液をそのまま他の材料と混合して光硬化性樹脂組成物を調製してもよく、遊離の付加物（ｂ−ｃ）や未反応の重合性化合物（ｃ）が光硬化性樹脂組成物中に混在していても、これらは多官能モノマーとして機能し、架橋密度を向上させる効果が得られる。
【０１２６】
以上のようにして得られる光硬化性樹脂組成物を基材フィルム等の支持体の表面に塗布し、必要に応じて乾燥させて光硬化性樹脂組成物の層（微細凹凸パターン形成層）を形成して凹凸パターン受容体を作製し、当該凹凸パターン受容体の微細凹凸パターン形成層表面にスタンパーを圧接してエンボス加工を行い、微細凹凸パターン形成層を露光して硬化させることにより、光学的機能を有する微細凹凸パターンを形成することができ、光学物品やスタンパーとして利用できる。
【０１２７】
また、この光硬化性樹脂組成物により、上述したような高度な光学的機能を有する複雑な微細凹凸パターンを精度良く且つエンボス加工により大量連続生産することが可能になる。
【０１２８】
以下において上記光硬化性樹脂組成物を用いる微細凹凸パターン形成方法、微細凹凸パターン転写箔について述べる。
【０１２９】
支持体に、本発明に係る光硬化性樹脂組成物を支持体上に塗工して微細凹凸パターン形成層を形成する前後、或いは、微細凹凸パターン形成層に微細凹凸パターンを形成する前後に、必要に応じて支持体又は微細凹凸パターン形成層の上にアンカー層、剥離層、金属薄膜層、オーバーコート層、感圧又は感熱接着剤層等の他の層を形成してもよい。
【０１３０】
微細凹凸パターン形成層は、スタンパーを圧接した状態で硬化させてもよいが、スタンパーを取り外した後で露光、加熱することも可能である。後者の方法は、微細凹凸パターン形成層を硬化工程に移す前にスタンパーを取り外し、取り外したスタンパーはエンボス工程で連続使用できるので連続生産性に優れている。
【０１３１】
また、本発明では、上記光硬化性樹脂組成物が成膜性及び離型性に優れていることを利用し、基材フィルム上に微細凹凸パターン形成層を形成した中間積層体をロール状に巻き取って一時的に貯蔵し、別の場所へ運搬して巻き戻し、スタンピング及び硬化を行うことも可能である。
【０１３２】
さらにスタンピング及び硬化を行った中間積層体をロール状に巻き取って一時的に貯蔵し、別の場所へ運搬し巻き戻し、必要に応じて追加の光硬化工程を行って充分に硬化させたり、或いは、必要に応じて金属薄膜、オーバーコート層、感圧又は感熱接着剤層等を形成することが可能である。
【０１３３】
凹凸パターン受容体は、微細凹凸パターンの表面構造を付与すべき最終製品であってもよいが、中間的な転写媒体であってもよい。すなわち本発明においては、上記光硬化性樹脂組成物を第一の支持体に塗布して微細凹凸パターン形成層を形成することで転写箔（凹凸パターン受容体）を作製し、この転写箔の微細凹凸パターン形成層に微細凹凸パターンを形成し、当該微細凹凸パターン形成層を硬化させた後で、第二の支持体（最終製品）上に転写することが可能である。転写箔を用いる場合には、最終製品の表面に直接エンボス加工を行う必要が無い、或いは、転写箔上に予め微細凹凸パターンを大量連続形成することができる等の利点があり、例えば、複雑な表面形状の物品等の直接エンボス加工を行うことが困難な物品の表面や、ロール状に巻き取ることができないガラス、プラスチック、金属板等の支持体に、微細凹凸パターンを連続転写によって形成することも可能である。
【０１３４】
本発明において微細凹凸パターン転写箔は、第一の支持体上に、少なくとも本発明に係る前記光硬化性樹脂組成物からなり、且つ、第一の支持体から剥離して第二の支持体に転写することが可能な状態で微細凹凸パターン形成層が設けられている積層体であり、必要に応じて、上記微細凹凸パターン形成層に加えて剥離層、反射層、接着剤層或いはその他の層の１又は２以上を設けることができる。例えば図１に示すように、転写箔１は、支持体２上に剥離層３、微細凹凸パターン形成層４、反射層５、及び、接着剤層６を順次積層した構成としてもよい。
【０１３５】
転写箔を作製する場合の支持体としては、通常、可撓性のある基材フィルムが用いられ、強度や耐熱性等の点でポリエチレンテレフタレート等のプラスチックフィルムが適しているが、プラスチックフィルムに限られず、また、可撓性が無くてもよく、金属板や紙等の他の材質を支持体として利用してもよい。また、紙等の含浸性ある支持体を用いる場合には、支持体組織内に微細凹凸パターン形成層が含浸した状態で形成されてもよく、このような状態であっても支持体上に設けられた微細凹凸パターン形成層の一形態に含まれる。また、ホログラム等の微細凹凸パターンの大量生産性を考慮して基材フィルムとして連続フィルムを用いてもよいが、枚葉状の基材フィルムを用いてもよい。
【０１３６】
剥離層は、転写箔の剥離性や箔切れ性を向上させる目的で微細凹凸パターン形成層の下層に必要に応じて設けられ、転写箔から何らかの被転写面（第二の支持体）に微細凹凸パターン形成層と共に転写された後は最表面になる層である。剥離層としては、例えば、アクリル樹脂、ポリエステル樹脂、ポリ塩化ビニル樹脂、セルロース樹脂、シリコーン樹脂、塩化ゴム、カゼイン、各種界面活性剤、金属酸化物等の中から１種のみ選んで単独で又は２種以上を選んで混合して用いることができる。または、微細凹凸パターン形成層に使用する本発明の光硬化性樹脂組成物に、これらを添加剤として添加したものも、剥離層として用いることができる。
【０１３７】
反射層は、例えばレリーフホログラムを形成する場合に微細凹凸パターン上に設けられる。反射層は、金属薄膜、又は、高屈折率材料の塗工液を用いて形成した高屈折率膜で形成できる。
【０１３８】
金属薄膜は、例えば、Ｃｒ、Ｔｉ、Ｆｅ、Ｃｏ、Ｎｉ、Ｃｕ、Ａｇ、Ａｕ、Ｇｅ、Ａｌ、Ｍｇ、Ｓｂ、Ｐｂ、Ｐｄ、Ｃｄ、Ｂｉ、Ｓｎ、Ｓｅ、Ｉｎ、Ｇａ、Ｒｂ等の金属及びその酸化物、窒化物、硫化物等を単独若しくは２種類以上組み合わせた混合物からなり、化学蒸着や物理蒸着等の方法で形成できる。また、高屈折率材料膜は、例えば、高屈折率フィラーを分散した塗工液の塗工、金や銀のコロイド溶液の塗工、ゾルゲル反応に代表される有機金属化合物の加水分解重縮合反応による塗膜形成等により形成できる。
【０１３９】
また、接着剤層は、微細凹凸パターン形成層の転写性、及び、転写後における被転写面に対する密着性を向上させる目的で、或いは、エンボス加工後の微細凹凸パターン形成層の表面を反射膜や保護膜で被覆する場合には、これらの層に対する密着性を向上させる目的で微細凹凸パターン形成層の最表面に設けられ、微細凹凸パターン形成層と共に転写された後は最下層となる層である。
【０１４０】
接着剤層としては、感熱性接着性樹脂として公知のものを使用できる。例えば、ポリイソプレンゴム、ポリイソブチレンゴム、スチレンブタジエンゴム等のゴム系；ポリ（メタ）アクリル酸メチル、ポリ（メタ）アクリル酸エチル、ポリ（メタ）アクリル酸プロピル、ポリ（メタ）アクリル酸ブチル、ポリ（メタ）アクリル酸−２−エチルヘキシル等の（メタ）アクリル酸エステル系；ポリイソブチルエーテル等のポリビニルエーテル系；ポリ酢酸ビニル、塩化ビニル−酢酸ビニル共重合体等のポリ塩化ビニル系；ポリアクリルアミド、ポリメチロールアクリルアミド等のポリアミド系；ポリ塩化ビニル等の塩化ビニル系；ポリビニルブチラール、酢酸ビニル／アクリル酸オクチル、酢酸ビニル／アクリル酸ブチル、塩化ビニリデン／アクリル酸ブチル等の他のビニル系；ポリスチレン等の芳香族ビニル系；及びポリ塩化オレフィン等が挙げられ、これらの中から１種のみ選んで単独で又は２種以上を組み合わせて用いることができる。
【０１４１】
本発明の微細凹凸パターン形成方法を、レリーフホログラムの転写箔を例にとって具体的に説明する。なお、使用される符号は図１を参照するためのものである。先ず、ポリエチレンテレフタレート等の連続プラスチックからなる基材フィルム２をロールストックから繰り出す。繰り出した基材フィルムの上に剥離剤の塗工液をロールコーターを用いて塗布し、次いで、前記塗工液に含まれている有機溶剤が飛散する温度、例えば、ｌ００〜１６５℃に設定した加熱炉内に０．１〜１分間程度導いて乾燥させて、剥離層３を形成する。この剥離層３の上に、引き続き光硬化性樹脂組成物からなる微細凹凸パターン形成材料をロールコーターを用いて塗布し、次いで、組成物に含まれている有機溶剤が飛散する温度、例えば、ｌ００〜１６５℃に設定した加熱炉１０内に０．１〜１分間程度導いて乾燥させて微細凹凸パターン形成層４を形成して転写箔１を作製する。上記ロールコーター以外の塗工機としては、例えばカーテンコーター、フローコーター、リップコーター、ドクターブレードコーター、グラビアコーター等も使用できる。微細凹凸パターン形成層の厚さは、通常０．１〜５．０μｍ程度である。作製した転写箔１は再び巻き取られてロールストックとされ、保存又は運搬される。
【０１４２】
次に、転写箔１をロールストックから繰り出し、微細凹凸パターン形成層の表面にレリーフホログラムのスタンパーを圧接してエンボス加工を行い、微細凹凸パターン（図示せず）を形成する。
【０１４３】
ホログラムパターンのエンボス加工は、例えば、レーザー光や電子線を用いて作った母型から引き続き作成したスタンパーを周面に装着した金属ロ−ルとペーパーロールよりなる１対のエンボスローラーを使用して通常の方法で、例えば、熱ロール温度１００〜２００℃、プレス圧５×１０³〜５×１０⁶Ｐａで行う。この範囲のプレス条件でエンボス加工を行う場合には、微細凹凸パターン形成層の樹脂温度が６０〜８０℃の温度域内又はその付近の温度に調節され、エンボス加工に適している。熱ロール温度を上記範囲より高くすると、エンボス加工を高速で行うことができるが、基材フィルムのダメージが大きくなる。また、熱ロール温度を上記範囲より低くすると、樹脂温度を上昇させるのに時間がかかるので、エンボス工程が遅くなる。なお、複製装置のエンボスローラーとしては、樹脂製版によりマスターホログラムから複製ホログラムを作成し、これをシリンダー上に貼り付けたものも使用できる。
【０１４４】
エンボス加工は片面エンボスで充分であるが、両面エンボスでもよい。エンボスに当たっては、エンボスロールの温度設定が重要であり、エンボス形状を再現する観点からは比較的高温で、比較的高い圧力でエンボスするのが好ましいが、エンボス版への付着を防止するためには比較的低い圧力でエンボスするのが好ましく、全く逆の関係となる。また、有効に作用する熱容量から考えた場合は、複製するフイルムの搬送速度も重要である。光硬化性樹脂組成物のエンボスロールへの付着を低減するためには、上述した離型剤の選定も重要である。
【０１４５】
光硬化性樹脂層にエンボス加工を行い、スタンパーから剥がした後、光を照射して樹脂層を硬化させる。硬化に用いる光としては、高エネルギー電離放射線及び紫外線が挙げられる。高エネルギー電離放射線源としては、例えば、コッククロフト型加速器、ハンデグラーフ型加速器、リニヤーアクセレーター、ベータトロン、サイクロトロン等の加速器によって加速された電子線が工業的に最も便利且つ経済的に使用されるが、その他に放射性同位元素や原子炉等から放射されるγ線、Ｘ線、α線、中性子線、陽子線等の放射線も使用できる。紫外線源としては、例えば、紫外線螢光灯、低圧水銀灯、高圧水銀灯、超高圧水銀灯、キセノン灯、炭素アーク灯、太陽灯等が挙げられる。
【０１４６】
硬化後、微細凹凸パターンの上には、必要に応じて、さらに金属蒸着層のような反射膜や、耐擦傷性や耐汚染性を高めるための透明保護膜を形成してもよい。また、微細凹凸パターン形成層の上に反射膜や保護膜等の層を付加する場合には、さらにその上に接着剤層を付加してもよい。
【０１４７】
光硬化させた樹脂層には反射膜を設ける必要がある。反射膜として光を反射する金属薄膜を用いると不透明タイプのホログラムとなり、透明な物質でホログラム層と屈折率差がある反射膜を設ける場合は透明タイプとなるが、どちらも使用できる。反射膜等の金属薄膜は、昇華、真空蒸着、スパッタリング、反応性スパッタリング、イオンプレーティング、電気メッキ等の公知の方法で形成可能である。
【０１４８】
不透明タイプのホログラムを形成する金属薄膜としては、例えば、Ｃｒ、Ｔｉ、Ｆｅ、Ｃｏ、Ｎｉ、Ｃｕ、Ａｇ、Ａｕ、Ｇｅ、Ａｌ、Ｍｇ、Ｓｂ、Ｐｂ、Ｐｄ、Ｃｄ、Ｂｉ、Ｓｎ、Ｓｅ、Ｉｎ、Ｇａ、Ｒｂ等の金属及びその酸化物、窒化物等を単独若しくは２種類以上組み合わせて形成される薄膜を用いることができる。上記金属薄膜の中でもＡｌ、Ｃｒ、Ｎｉ、Ａｇ、Ａｕ等が特に好ましく、その膜厚は１〜１０，０００ｎｍ、望ましくは２０〜２００ｎｍの範囲である。
【０１４９】
透明タイプのホログラムを形成する薄膜は、ホログラム効果を発現できる光透過性のものであれば、いかなる材質のものも使用できる。例えば、微細凹凸パターン形成層の樹脂と屈折率の異なる透明材料を用いることができる。この場合の屈折率は、ホログラム形成層の樹脂の屈折率より大きくても小さくてもよいが、屈折率の差は０．１以上が好ましく、０．５以上がより好ましく、１．０以上が特に好ましい。また、上記以外の透明タイプには、２０ｎｍ以下の金属性反射膜がある。好適に使用される透明タイプ反射層としては、酸化チタン（ＴｉＯ₂）、硫化亜鉛（ＺｎＳ）等が挙げられる。
【０１５０】
このようにして微細凹凸パターン形成層の上に、微細凹凸パターンを形成し硬化させた転写箔は、再び巻き取られてロールストックとされ、保存又は運搬される。
【０１５１】
次に、微細凹凸パターンを形成した転写箔をロールストックから繰り出し、その微細凹凸パターン形成層の上に、第二の支持体の被転写面を向き合わせて重ね合せ、ホログラムを転写しようとする部分の転写箔を基材フィルム側から加圧ローラや加圧板で加熱・加圧して溶融接着させた後、転写箔を剥離することにより、微細凹凸パターンを有する微細凹凸パターン形成層が第二の支持体上に転写される。転写の際の温度及び圧力は、加圧方式（ロール式、スタンピング式）及び加圧時間等の加圧方法に関する要因のほか、支持体の材質と溶融温度、感熱接着剤の溶融温度、感熱接着剤と支持体材質の密着性等の要因によって条件が大きく異なってくるため、適宜調節する。
【０１５２】
このようにして、光硬化性樹脂組成物の硬化物からなると共に、レリーフホログラムの微細凹凸パターンが形成された表面構造を有する硬化樹脂層を備えた光学物品が得られる。
【０１５３】
本発明によれば、上記レリーフホログラムと同様の方法により又は上記方法を必要に応じて修正して、光硬化性樹脂組成物の硬化物からなると共に、様々な光学的機能を有する微細凹凸パターンが形成された表面構造を有する硬化樹脂層を備えた光学物品を作製することが可能である。
【０１５４】
本発明の光硬化性樹脂組成物を用いるエンボス加工により作製される光学物品としては、（１）セキュリティ用途で使用されるレリーフホログラムや回折格子、例えばクレジットカード、ＩＤカード、商品券、紙幣等に付されるものや、（２）グラフィックアーツ及び意匠用途で使用されるレリーフホログラムや回折格子、例えば、いわゆるプリクラ等のアミューズメント商品又は景品、包装、葉書・封書、ノベルティグッズ等に付されるものや、（３）全光線及び／又は特定の波長の光の反射、透過、散乱、偏光、集光又は干渉の少なくとも一つを制御する光学素子、例えば、反射板、散乱板、偏光板、レンズ、波長選択素子、反射防止板、複屈折波長板、サブ波長構造を持つ光学素子等の光学素子等として用いられるものや、（４）情報記録素子、例えば、情報記録ホログラム、光カード、光ディスク等として用いられるもの等を挙げることができる。
【０１５５】
本発明は、レリーフホログラムや回折格子以上に複雑又は精密に光を制御する用途に適用可能であるが、レリーフホログラムや回折格子に適用する場合にも、ただ単に明るいホログラムを得るだけでなく、複雑なデザインをもつレリーフホログラムや回折格子を形成できる。
【０１５６】
さらに本発明によれば、非常に高い精度で微細凹凸パターンを形成できるので、光学物品に付与すべき微細凹凸パターンを型にして相補的な凹凸パターンを複製し、これをスタンパーとして使用することが可能である。
【０１５７】
【実施例】
Ａ．製造例
Ａ−１ 水酸基を持つアクリル樹脂ａの合成
（製造例１）
冷却器、滴下ロート及び温度計付きの２リットルのフラスコに、トルエン４０ｇ、メチルエチルケトン４０ｇを、アゾ系の重合開始剤と共に仕込み、２−ヒドロキシエチルメタクリレート２１．０ｇ、メチルメタクリレート５８．０ｇ、イソボルニルメタクリレート２２．５ｇ、トルエン３０ｇ、メチルエチルケトン２０ｇの混合液を滴下ロートで滴下させながら、１００℃の温度下で８時間反応させた後、室温まで冷却し、水酸基を持つアクリル樹脂ａの樹脂溶液を得た。
【０１５８】
Ａ−２ イソシアネート基含有ウレタンアクリレートの合成
（製造例２）
冷却器、滴下ロート及び温度計付きの２リットルのフラスコに、メチルエチルケトン１２０．０ｇ、イソホロンジイソシアネート３３．０ｇを仕込み、グリセリンアクリレートメタクリレート（商品名：７０１Ａ、新中村化学工業製）５５．３ｇ、ラウリン酸ジブチルスズを加えて反応させ、イソシアネート基含有ウレタンアクリレートｂの樹脂溶液を得た。
【０１５９】
（製造例３）
上記ウレタンアクリレートｂの合成で用いたグリセリンアクリレートメタクリレートをテトラメチロールメタントリアクリレート（商品名：Ａ−ＴＭＭ−３−ＬＭＮ、新中村化学工業製）８８．４ｇに変更して、イソシアネート基含有ウレタンアクリレートｃの樹脂溶液を得た。
【０１６０】
Ｂ．実施例及び比較例
Ｂ−１ 光硬化性樹脂の合成
（実施例１）
前記製造例１で得られたアクリル樹脂ａの樹脂溶液４０．０ｇに対し、前記製造例２で得られたイソシアネート基含有ウレタン化アクリレートｂの樹脂溶液を４５．５ｇ添加し、ラウリン酸ジブチルスズを触媒として付加反応させた。反応生成物のＩＲ分析によりイソシアネート基の吸収ピークの消失を確認し、反応を終了した。重量平均分子量（ポリスチレン換算）が約４７０００のアクリル樹脂Ａを得た。
【０１６１】
（実施例２）
前記製造例１で得られたアクリル樹脂ａの樹脂溶液４０．０ｇに対し、前記製造例２で得られたイソシアネート基含有ウレタン化アクリレートｂの樹脂溶液を１４５．８ｇ添加し、ラウリン酸ジブチルスズを触媒として付加反応させた。反応生成物のＩＲ分析によりイソシアネート基の吸収ピークの消失を確認し、反応を終了した。重量平均分子量（ポリスチレン換算）が約４００００のアクリル樹脂Ｂを得た。
【０１６２】
（実施例３）
前記製造例１で得られたアクリル樹脂ａの樹脂溶液６０．０ｇに対し、前記製造例３で得られたイソシアネート基含有ウレタン化アクリレートｃの樹脂溶液を８２．５ｇ添加し、ラウリン酸ジブチルスズを触媒として付加反応させた。反応生成物のＩＲ分析によりイソシアネート基の吸収ピークの消失を確認し、反応を終了した。重量平均分子量（ポリスチレン換算）が約１７２０００のアクリル樹脂Ｃを得た。
【０１６３】
Ｂ−２ 光硬化性樹脂組成物の調製
（実施例４）
下記組成に従って各成分を混合し、光硬化性樹脂組成物１を得た。
＜光硬化性樹脂組成物１の組成＞
・実施例１のアクリル樹脂Ａ：８０重量部（固形分換算）
・ウレタンアクリレートオリゴマー（商品名：紫光ＵＶ−１７００Ｂ、日本合成化学工業製）：２０重量部
・シリコーン系離型剤（商品名：Ｘ−２４−８２０１、信越化学工業製）：５重量部
・光開始剤（商品名：イルガキュア９０７、チバスペシャルティケミカルズ製）：５重量部
【０１６４】
（実施例５）
下記組成に従って各成分を混合し、光硬化性樹脂組成物１を得た。
＜光硬化性樹脂組成物２の組成＞
・実施例１のアクリル樹脂Ｂ：９０重量部（固形分換算）
・シリコーン系離型剤（商品名：ＢＹＫ−３７１、ビックケミー製）：５重量部・光開始剤（商品名：イルガキュア９０７、チバスペシャルティケミカルズ製）：５重量部
【０１６５】
（実施例６）
下記組成に従って各成分を混合し、光硬化性樹脂組成物３を得た。
＜光硬化性樹脂組成物３の組成＞
・実施例１のアクリル樹脂Ｃ：９０重量部（固形分換算）
・シリコーン系離型剤（商品名：Ｘ−２１−３０５６、信越化学工業製）：５重量部
・光開始剤（商品名：イルガキュア９０７、チバスペシャルティケミカルズ製）：５重量部
【０１６６】
（比較例１）
下記組成に従って各成分を混合し、比較組成物１を得た。
＜比較組成物１の組成＞
・製造例１のアクリル樹脂ａ（未変性物）：８０重量部（固形分換算）
・ウレタンアクリレートオリゴマー（商品名：紫光ＵＶ−１７００Ｂ、日本合成化学工業製）：２０重量部
・シリコーン系離型剤（商品名：Ｘ−２４−８２０１、信越化学工業製）：５重量部
【０１６７】
Ｂ−３ ラベルタイプ微細凹凸パターンシートの作製
上記実施例及び比較例で得られた樹脂組成物を各々、厚さ５０μｍの片面易接着性処理ポリエチレンテレフタレートフィルム（ダイアホイルＴ６００Ｅ Ｕ−３６、ダイアホイルへキスト製）の易接着性処理面上にグラビアコーターで塗工し、１００℃で乾燥して溶剤を揮発させて、乾燥時塗工量が２ｇ／ｍ²の複製用感光性フィルムを形成した。この複製用感光性フィルムは、比較例で得られた樹脂組成物を用いて作製したものを含め、いずれも表面タックはなく、巻取り状態でブロッキングを起こさないものであった。
【０１６８】
次に、複製装置のエンボスローラーに、電子線描画により形成した回折格子（ピッチ０．８μｍ）から作製したプレススタンパーを設置した。複製用感光性フィルムを、当該複製装置の給紙側にセットし、加熱ローラーを１５０℃に設定して加熱プレスし、エンボスローラーから剥離して、回折格子パターンを形成した。複製品は、比較例で得られた樹脂組成物を用いて作製したものを含め、いずれも版取られを起こさず、離型性が良好であった。
【０１６９】
次に、高圧水銀灯により紫外線を照射して、複製用感光性フィルムを光硬化させ、引き続き、真空蒸着法によりアルミニウムを蒸着して、回折格子フィルム（微細凹凸パターンシート）を作製した。回折格子フィルムは、比較例で得られた樹脂組成物を用いて作製したものを含め、いずれも光沢があり、光沢が暗くなっている部分や欠けている部分等はなく、良好であった。
【０１７０】
Ｂ−４ 評価
（１）回折格子フィルムの耐熱性
上記の回折格子フィルムを１００℃のオーブンに５時間入れ、回折格子の光沢、明るさを加熱前後で比較し、下記基準で評価した。結果を第１表に示す。
＜耐熱性の評価基準＞
○：変化無し
×：光沢が無く、全体的に暗くなっている
【０１７１】
（２）回折格子形成ガラス板の耐熱性
スライドガラス上に、実施例及び比較例で得られた樹脂組成物を各々、スピンコーターで塗工し、１００℃のオーブンで乾燥して溶剤を揮発させて、乾燥時塗工量が３ｇ／ｍ²の塗膜を形成した。この塗膜上に、電子線描画により形成した回折格子（ピッチ０．８μｍ）から作製したプレス用ニッケルスタンパーを重ねて、ホットプレート上で充分加熱した後、加熱ラミネーターで凹凸パターンをエンボスした。
【０１７２】
続いて、高圧水銀灯により積算露光量が６００ｍＪ／ｃｍ²になるように紫外線を照射し、回折格子パターンを表面に有するガラス板を作製した。
【０１７３】
得られた回折格子パターン形成ガラス板を２００℃のオーブンに１時間おき、その表面を観察し、下記基準に従って評価した。結果を第１表に示す。
＜回折格子形成ガラス板の評価基準＞
○：変化無し
×：光沢が無く、全体的に暗くなっている
【０１７４】
（３）硬化後の耐摩耗性
実施例及び比較例で得られた樹脂組成物を各々、厚さ５０μｍの片面易接着性処理ポリエチレンテレフタレートフィルム（ダイアホイルＴ６００Ｅ Ｕ−３６、ダイアホイルへキスト製）の易接着性処理面上にグラビアコーターで塗工し、１００℃で乾燥して溶剤を揮発させて、乾燥時塗工量が２ｇ／ｍ²の複製用感光性フィルムを形成した。
【０１７５】
続いて、フィルムに高圧水銀灯により積算露光量が６００ｍＪ／ｃｍ²になるように紫外線を照射した。得られた硬化フィルムは、ＪＩＳ Ｋ−７２０４に基づき、テーバー（Ｔａｂｅｒ）摩耗試験を行った。摩耗輪はＣＳ−１０を使用し、荷重を２５０ｇとした。試験開始前と２００回転後のヘイズ差を評価した。結果を第１表に示す。
【０１７６】
（４）樹脂組成物の動的粘弾性、ガラス転移温度
実施例及び比較例で得られた樹脂組成物を各々、ポリエステルフィルム上に塗工し、室温で乾燥して溶剤を揮発させて、乾燥時塗工量が５０ｇ／ｍ²のキャストフィルムを形成した。このキャストフィルムは、幅５．０ｍｍ、長さ１２ｍｍの短冊状にカットし、高圧水銀灯により積算露光量が６００ｍＪ／ｃｍ²になるように紫外線を照射した。
【０１７７】
硬化させたキャストフィルムの動的粘弾性は、固体粘弾性アナライザーＲＳＡ−ＩＩ（レオメトリック製）を使用して行なった。測定条件は、基本測定周波数を１Ｈｚとして、温度範囲を３０〜３００℃、昇温速度５℃／ｍｉｎで測定した。測定により得られるｔａｎδ（動的損失弾性率／動的貯蔵弾性率）のピークをガラス転移温度とした。結果を第１表に示す。
【０１７８】
【表１】

【発明の効果】
以上に述べたように、本発明に係る光硬化性樹脂は、前記イソシアネート化合物（ｂ）の１分子内に含まれるイソシアネート基の１つが、前記重合体（ａ）の主鎖にぶら下がるペンダント構造に含まれる水酸基とウレタン結合すると共に、このイソシアネート化合物（ｂ）の同じ分子内に含まれる別のイソシアネート基が、前記重合性化合物（ｃ）の水酸基とウレタン結合した構造であり、その分子内に多量のウレタン結合構造と多量の光重合性官能基を含有させることができる。
【０１７９】
この光硬化性樹脂は、硬化前においては室温で高粘度又は固体状の熱成形性を有する塗膜を形成できる成膜性、微細凹凸パターンをスタンパ−で精密に複製し得る熱可塑性、スタンパ−を剥離した後でも型崩れにしにくい形状維持性、及び、耐ブロッキング性を有しており、硬化後においては、強度、耐熱性、耐擦傷性、耐水性、耐薬品性、被塗布面（代表的には基材）に対する密着性、基材の屈曲や伸縮に追随できる可とう性等の諸物性にも優れている。
【０１８０】
特に、上記重合性化合物（ｃ）として一分子内に光重合性官能基を２つ以上有するものを用いる場合には、重合体（ａ）の水酸基１つ当たり光重合性官能基が２つ以上導入されるので、架橋密度が非常に大きくなり、硬化後の諸物性を向上させる効果が高い。架橋密度の増大によって、とりわけ耐熱性、耐久性（耐摩耗性、耐薬品性、耐水性）が向上し、高熱、摩擦又は溶剤に曝されても、微細凹凸パターンの変形、消失、損傷が起こり難い。
【０１８１】
また、重合体（ａ）に付加物（ｂ−ｃ）を反応させる方法で得られる光硬化性樹脂は、副生物又は未反応体による悪影響が少ないため、これらが混在したままの状態でも凹凸パターン形成材料として利用可能であり、精製の手間が省ける点で有利である。
【０１８２】
本発明に係る光硬化性樹脂組成物は、優れた離型性を有する上記光硬化性樹脂に対し離型剤を必須成分として配合することにより、さらに離型性を改善しているので、光硬化性樹脂組成物の層に押し付けたスタンパーを、樹脂層の面荒れや版取られを起こさずにきれいに剥離することができ、且つ、剥離の際にスタンパー内に樹脂の一部が残らないので反復エンボス性にも優れており、微細凹凸パターンの精度及び連続生産性の点で特に優れている。
【０１８３】
この光硬化性樹脂組成物に有機溶媒にコロイド状に分散させることが可能な無機微粒子を含有させる場合には賦型性、形状維持性及び離型性がさらに向上し、微細凹凸パターンを有する表面構造を精度よく複製でき、特に、近年の非常に複雑な微細凹凸パターンも正確に複製できる。また、微細凹凸パターンの精度が上がるだけでなく、耐ブロッキング性も上がることから、未硬化の状態でロール状に巻き取って保管、運搬可能となる。
【０１８４】
また、本発明に係る微細凹凸パターン形成方法によれば、以上述べたところから明らかなように、精度が高く且つ硬化後物性に優れた微細凹凸パターンを連続大量生産することが可能である。
【０１８５】
また、上記光硬化性樹脂組成物は、微細凹凸パターン形成層を形成した後、未硬化の状態でロール状に巻き取ってもブロッキングを起こし難いので、微細凹凸パターン転写箔を形成することも可能である。微細凹凸パターン転写箔を利用する場合には、生産性をさらに向上させることができる。
【０１８６】
本発明によれば、レリーフホログラムや回折格子の微細凹凸パターンを複製できることは言うまでもなく、より高度な光学的機能を有する複雑な微細凹凸パターンを精度良く且つエンボス加工により大量連続生産することが可能となり、具体的には、全光線及び／又は特定の波長の光の反射、透過、散乱、偏光、集光又は干渉の少なくとも一つを制御する光学素子や、情報記録素子等の微細凹凸パターンを形成することができる。
【０１８７】
さらに本発明によれば、非常に高い精度で微細凹凸パターンを形成できるので、光学物品に付与すべき微細凹凸パターンを型にして相補的な凹凸パターンを複製し、これをスタンパーとして使用することが可能である。
【図面の簡単な説明】
【図１】微細凹凸パターン転写箔の一例についての模式的断面図である。
【符号の説明】
１…転写箔
２…支持体
３…剥離層
４…微細凹凸パターン形成層
５…反射層
６…接着層[0001]
BACKGROUND OF THE INVENTION
The present invention is capable of forming a coating film having excellent post-curing physical properties in terms of strength, heat resistance, flexibility, or other aspects, as well as excellent ability to form a fine concavo-convex pattern and other processability before curing. Photocurable resin, photocurable resin composition containing the resin, method of forming a fine uneven pattern using the resin composition, and transfer foil, optical article, and stamper using the resin composition About.
[0002]
[Prior art]
Conventionally, a photocurable resin composition is applied onto a support, for example, to form a photocurable resin layer, and a fine uneven pattern is applied to the surface of the photocurable resin layer. The resin layer is cured by exposure with active energy rays such as a light-reflective layer such as a metal vapor deposition film or a layer having a refractive index different from that of the resin layer as a reflective layer on the formed uneven pattern surface. As a result, optical articles such as diffraction gratings and relief holograms are produced and used for decoration of various cards and securities, and for the purpose of preventing counterfeiting.
[0003]
As one of the methods for forming a resin layer having a fine concavo-convex pattern that exhibits such an optical function, a liquid photocurable resin composition is applied onto a transparent support such as a polyester film to obtain a liquid light. There is a so-called 2P method (Photo Polymer method) in which a curable resin layer is formed, a stamper having fine irregularities is pressed onto it and cured by light irradiation from the support side, and then the stamper is removed. However, in this method, since light is irradiated from the back side of the support, if the support has light absorption, the curing is insufficient, the stamper cannot be removed until the curing is completed, and the process takes time. Since the curable resin layer is in a liquid state, air bubbles are likely to enter between the stamper and the stamper that is in pressure contact, or when the stamper is peeled off from the cured resin layer, stringing occurs on the surface of the resin layer, causing surface roughness. There is.
[0004]
As another method, a photocurable resin composition having a high viscosity or a solid at room temperature is coated on a support to form a photocurable resin layer, and then a stamper is pressed onto and peeled off, followed by light irradiation. There is a method of curing by performing (Japanese Patent Publication No. 5-46063, Japanese Patent Publication No. 6-85103). According to this method, the photocurable resin layer can be sufficiently cured because it is directly irradiated with light. Since the photocurable resin composition is highly viscous or solid, the support is wound up after storage or stored. Photocurable resin layer that can be transported and can be applied and replicated in separate processes, and the stamper can be peeled off and irradiated with light, so that the stamper can be pressed and cured in separate processes There is an advantage that bubbles can hardly enter between the stamper and the pattern can be formed accurately, and when the stamper is peeled off from the photocurable resin layer, the surface of the resin layer is less likely to be stringed.
[0005]
However, in the method using a photocurable resin composition having a high viscosity or a solid at room temperature, a part of the photocurable resin composition is adhered in the cavity of the stamper in order to peel off the stamper from the uncured resin layer. The stamper is peeled off from the uncured resin layer, which tends to remain (the phenomenon of plate-cutting), and the harder the photocurable resin composition flows into the cavity of the stamper as the uneven pattern to be replicated becomes finer. Then, since light is irradiated, there is a problem that pattern collapse is likely to occur until the curing is completed.
[0006]
Further, the cured resin layer obtained by applying a fine uneven pattern to the coating film of the photocurable resin composition and curing it has various physical properties that can withstand use as an optical article such as a diffraction grating or a relief hologram, for example, , Strength, hardness, heat resistance, durability (abrasion resistance, scratch resistance, chemical resistance, water resistance, etc.), adhesion to the substrate, and flexibility of the substrate and followability to expansion and contraction are required. Is done.
[0007]
Japanese Patent Application Laid-Open No. 2000-63459 describes a photocurable resin composition containing a urethane-modified acrylic resin having a bulky group and a release agent as essential components. Among the currently known materials, this resin composition can satisfy the performances required before and after curing to some extent.
[0008]
However, with the expansion of the use of optical articles that apply fine concavo-convex patterns, the photocurable resin composition used as the material is required to have further superior performance with respect to various physical properties before and after curing as described above. It has been.
[0009]
In particular, regarding heat resistance, for example, when a fine uneven pattern is provided on an optical article and heat-treated at a temperature of 200 ° C. or higher, or when the fine uneven pattern is used as a stamper for injection molding, It is required that the fine concavo-convex pattern formed by curing the photocurable resin composition does not deform or disappear even under an environment exposed to water or an environment where heat and pressure are applied simultaneously.
[0010]
As for durability, for example, when a fine uneven pattern functioning as a hologram is provided on the surface of a plastic card, or when the dirt attached to the hologram surface on the card is scraped with an organic solvent such as alcohol or acetone, Since it is assumed that the card is left under high temperature and high humidity, or is exposed to water, the fine concavo-convex pattern formed by curing the photocurable resin composition is rubbed in an environment subject to wear. Wear resistance or scratch resistance that will not be damaged or scraped even if mechanical external force is applied, etc., chemical resistance that does not elute with organic solvents, and durability such as water resistance that does not deform due to moisture Desired.
[0011]
Even with the resin composition described in JP-A No. 2000-63459, it is difficult to form an optical fine concavo-convex pattern having sufficient performance that can cope with such recent expansion of applications.
[0012]
  The present invention has been accomplished in view of the above-mentioned actual situation, and the first object thereof is excellent in the ability to form a fine uneven pattern and other processability before curing, and after curing, strength, heat resistance, Excellent film properties in flexibility or other aspectsA fine concavo-convex pattern forming method using a photocurable resin composition containing a photocurable resin, a fine concavo-convex pattern transfer foil using the photocurable resin composition and the fine concavo-convex pattern forming method, and a fine concavo-convex pattern It is to provide an optical article.
[0013]
  The second object of the present invention is, among various performances required for a fine concavo-convex pattern forming material, particularly excellent in heat resistance and durability of the fine concavo-convex pattern after curing. However, it contains a photo-curing resin that has a heat resistance that does not deform or disappear, and that can form a fine concavo-convex pattern that has excellent durability such as abrasion resistance, scratch resistance, chemical resistance, and water resistance.To provide a fine uneven pattern forming method using a photocurable resin composition, a fine uneven pattern transfer foil using the photocurable resin composition and the fine uneven pattern forming method, and an optical article having a fine uneven pattern. is there.
[0016]
[Means for Solving the Problems]
  An optical article according to the present invention provided to achieve the above object is a polymerizable compound (c) having at least an acrylic resin (a) having a hydroxyl group, one hydroxyl group, and one acryloyl group or methacryloyl group. A cured product of a photocurable resin composition containing a photocurable resin bonded through an isocyanate compound (b) having at least two isocyanate groups and a release agent as essential components And a surface structure on which a fine concavo-convex pattern is formed.
[0017]
  The second optical article provided in the present invention is a polymerizable compound (c) having at least an isocyanate compound (b) having at least two isocyanate groups, one hydroxyl group, and one acryloyl group or methacryloyl group. A photocurable resin composition containing, as essential components, a photocurable resin obtained by reacting an adduct (bc) obtained by reacting with an acrylic resin (a) having a hydroxyl group, and a release agent. And a surface structure on which a fine concavo-convex pattern is formed.
[0018]
  The photocurable resin used in the present invention isOne of the isocyanate groups contained in one molecule of the isocyanate compound (b) is urethane-bonded to a hydroxyl group contained in a pendant structure hanging from the main chain of the polymer (a), and the same isocyanate compound (b). Another isocyanate group contained in the molecule is a structure in which the hydroxyl group of the polymerizable compound (c) is urethane-bonded, and a large amount of urethane-bonded structure and a large amount ofAcryloyl group and / or methacryloyl groupCan be contained.
[0019]
This photo-curable resin is a film forming property capable of forming a highly viscous or solid thermoformable film at room temperature before curing, a thermoplastic resin capable of accurately replicating a fine uneven pattern with a stamper, a stamper It has shape retention and blocking resistance that is difficult to lose its shape even after peeling off, and after curing, strength, hardness, heat resistance, scratch resistance, water resistance, chemical resistance, surface to be coated It also has excellent physical properties such as adhesion to the substrate and flexibility to follow bending and expansion / contraction of the substrate.
[0020]
  The polymerizable compound (c) has two or more acryloyl groups and / or methacryloyl groups in one molecule, so that two or more acryloyl groups and / or methacryloyl groups are introduced per one hydroxyl group of the polymer (a). BecauseThe crosslinking density becomes very large, and the effect of improving various physical properties after curing, particularly heat resistance and durability (wear resistance, chemical resistance, water resistance) is high.
[0021]
In addition, since the photocurable resin obtained by the method of reacting the adduct (bc) with the polymer (a) is less adversely affected by by-products or unreacted substances, the concavo-convex pattern can be obtained even in the state where these remain mixed. It can be used as a forming material, and is advantageous in that it saves the labor of purification.
[0023]
  The photocurable resin composition used in the present invention isBy adding a release agent as an essential component to the photocurable resin having excellent release properties, the release property is further improved, so a stamper pressed against the layer of the photocurable resin composition is used. The resin layer can be peeled cleanly without causing surface roughness or plate removal, and since a part of the resin does not remain in the stamper at the time of peeling, it is excellent in repetitive embossing and a fine uneven pattern It is particularly excellent in terms of accuracy and continuous productivity.
[0024]
Silicone mold release agents are preferred because they have particularly good mold release properties from the stamper when combined with the above-mentioned photocurable resin used in the present invention, and the phenomenon of taking a plate hardly occurs.
[0026]
Therefore, according to the present invention, it is possible to obtain an optical article comprising a surface structure on which a fine concavo-convex pattern is formed which is composed of a cured product of the above-described photocurable resin composition and has high accuracy and excellent physical properties after curing. Needless to say, it is possible to reproduce a relief hologram or a fine concavo-convex pattern of a diffraction grating, a complex fine concavo-convex pattern having a higher optical function, for example, reflection, transmission, scattering of light of a total ray and / or a specific wavelength, Even an optical element that controls at least one of polarization, condensing, and interference, and a fine concavo-convex pattern such as an information recording element, can be mass-produced with high accuracy and by embossing.
[0027]
  Next, the fine uneven | corrugated pattern formation method based on this invention is a polymeric compound (a) which has at least the acrylic resin (a) which has a hydroxyl group, one hydroxyl group, and one acryloyl group or a methacryloyl group on a support body. a fine photo-curing resin composition comprising, as essential components, a photo-curable resin bonded with c) and an isocyanate compound (b) having at least two isocyanate groups, and a release agent. A concavo-convex pattern receptor provided with a concavo-convex pattern forming layer is prepared, a concavo-convex pattern is formed by pressing a stamper on the surface, and then the fine concavo-convex pattern forming layer is cured.
[0028]
  The second fine unevenness pattern forming method provided in the present invention comprises at least an isocyanate compound (b) having at least two isocyanate groups, one hydroxyl group, and one acryloyl group or methacryloyl group on a support. Contains, as an essential component, a photocurable resin obtained by reacting an adduct (bc) obtained by reacting a polymerizable compound (c) with an acrylic resin (a) having a hydroxyl group, and a release agent Preparing a concavo-convex pattern receptor provided with a fine concavo-convex pattern forming layer comprising a photocurable resin composition, forming a concavo-convex pattern by pressing a stamper on the surface, and then curing the fine concavo-convex pattern forming layer It is characterized by that.
[0029]
  According to the fine concavo-convex pattern forming method of the present invention, it is possible to continuously mass-produce fine concavo-convex patterns with high accuracy and excellent physical properties after curing.
[0030]
  In particular, the fine concavo-convex pattern forming layer can be wound on a roll stock and stored and transported as needed after the stamper is peeled off, and rewound again to cure the fine concavo-convex pattern by light irradiation. Excellent productivity.
[0031]
  In one aspect of the fine concavo-convex pattern forming method, a fine concavo-convex pattern transfer foil in which a fine concavo-convex pattern forming layer made of the photocurable resin composition is provided on a first support so as to be transferable is used. The fine concavo-convex pattern forming layer cured on the support of the concavo-convex pattern transfer foil can be transferred onto the second support. According to this method, fine irregularities are formed on the surface of an article that is difficult to directly emboss, such as an article having a complicated surface shape, or on a support such as glass, plastic, or metal plate that cannot be rolled up. The pattern can be formed by continuous transfer.
[0032]
DETAILED DESCRIPTION OF THE INVENTION
  The present invention is described in detail below. In this specification,(Meth) acrylateRepresents acrylate and methacrylate;(Meth) acrylicRepresents acrylic and methacrylic ((Meta) acryloylRepresents acryloyl and methacryloyl.
[0033]
The photocurable resin according to the present invention comprises a polymer (a) containing a structural unit having a hydroxyl group in the main chain skeleton, and a polymerizable compound (c) having at least one hydroxyl group and one photopolymerizable functional group. , Which are bonded via an isocyanate compound (b) having at least two isocyanate groups.
[0034]
That is, in this photocurable resin, one of the isocyanate groups contained in one molecule of the isocyanate compound (b) forms a urethane bond with a hydroxyl group contained in a pendant structure hanging from the main chain of the polymer (a). Another isocyanate group contained in the same molecule of the isocyanate compound (b) has a structure in which a urethane bond is formed with the hydroxyl group of the polymerizable compound (c). Therefore, this photocurable resin introduce | transduced at least 1 (preferably 2 or more) photopolymerizable functional group through two urethane bonds with respect to each hydroxyl group contained in a polymer (a). It can contain a large amount of urethane bond structure and a large amount of photopolymerizable functional group in the molecule.
[0035]
This photo-curable resin composition containing the photo-curable resin as a main component can be applied to any surface to be coated and dried as necessary to form a coating film having a high viscosity or solid thermoformability at room temperature. Can be formed. Since this coating film is not liquid, bubbles are difficult to enter when the stamper is pressed. Moreover, since this coating film is excellent in thermoplasticity, if it heats as needed, pressing a stamper, it will flow to every corner in the cavity of a stamper, and will be shape | molded correctly. Furthermore, this photocurable resin composition is excellent in releasability and shape maintainability, and even when the stamper is peeled off before curing, it does not cause surface roughness or plate removal, and can be left after being peeled off. Does not lose shape. Moreover, since this photocurable resin composition has a weak tackiness, even if the fine concavo-convex pattern receptor having a fine concavo-convex pattern forming layer made of this photocurable resin composition is wound or stacked before curing, Hard to cause blocking. Thus, the coating film which consists of a photocurable resin composition which has the photocurable resin which concerns on this invention as a main component is excellent in the fine unevenness | corrugation pattern formation ability and processability before hardening.
[0036]
Moreover, the fine concavo-convex pattern forming layer obtained by curing this coating film has strength, hardness, heat resistance, scratch resistance, water resistance, chemical resistance, and adhesion to the coated surface (typically the substrate). And various physical properties such as flexibility that can follow the bending and expansion / contraction of the substrate.
[0037]
In particular, when using a compound having two or more photopolymerizable functional groups in one molecule as the polymerizable compound (c), there are two or more photopolymerizable functional groups per one hydroxyl group of the polymer (a). Since it is introduced, the crosslinking density becomes very large, and the effect of improving various physical properties after curing is high.
[0038]
Among various physical properties after curing, heat resistance and durability (abrasion resistance, chemical resistance, water resistance) are improved by increasing the crosslinking density. For example, deformation and loss are less likely to occur even when the fine uneven pattern is exposed to a high temperature environment, particularly in a severe environment where heat and pressure are applied simultaneously due to improved heat resistance, and by improving wear resistance and scratch resistance, Even when a fine concavo-convex pattern such as a hologram is provided in a place that is easily exposed to a mechanical external force such as the surface of a credit card, it becomes difficult to be worn or scratched. Even when the surface is wiped with a solvent, it is difficult to elute.
[0039]
This photocurable resin is an adduct (b-) obtained by reacting an isocyanate compound (b) having at least two isocyanate groups with a polymerizable compound (c) having at least one hydroxyl group and one photopolymerizable functional group. It is possible to synthesize c) by reacting with a polymer (a) containing a structural unit having a hydroxyl group in the main chain skeleton.
[0040]
The structural unit having a hydroxyl group in the polymer (a) means a structural unit having a hydroxyl group in a pendant structure hanging from the main chain of the polymer (a) (including a case where the pendant structure is a hydroxyl group itself), It is a component for introducing a photopolymerizable functional group through the isocyanate compound (b). Therefore, the content ratio of the structural unit having a hydroxyl group is adjusted in consideration of the degree of photopolymerization required for the photocurable resin.
[0041]
As the monomer used for introducing the structural unit having a hydroxyl group into the main chain of the polymer, a compound having an ethylenically unsaturated bond-containing group and a hydroxyl group can be used.
[0042]
As the structural unit having a hydroxyl group, a structural unit represented by the following formula (1) is preferable.
[0043]
[Chemical 1]

[0044]
(Wherein R¹Represents hydrogen or an alkyl group having 1 to 5 carbon atoms, and X represents a single bond or a divalent atomic group. )
R contained in formula (1)¹Represents hydrogen or an alkyl group having 1 to 5 carbon atoms, and examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl and the like. Is done.
[0045]
The structure of X contained in Formula (1) is not particularly limited, and may be a single bond in which a hydroxyl group is directly bonded to the main chain, or may be any divalent atomic group. The divalent atomic group includes a branched, aliphatic carbocyclic ring, aromatic carbocyclic ring, or an alkylene group which may have a substituent, or a chemical structure such as an ester group, an amide group, an ether group, or an alkylene oxide chain. The hydrocarbon chain containing can be illustrated.
[0046]
If the molecular chain of the divalent atomic group X is shortened, the cross-linking becomes dense, which is effective when high hardness is required for the resin composition. Conversely, if the molecular chain is lengthened, an isocyanate group is added to the hydroxyl group. Since the photopolymerizable functional group introduced via the compound (b) becomes easy to move and the reactivity becomes high, a flexible and strong resin can be obtained.
[0047]
As the structural unit represented by the formula (1), a structural unit represented by the following formula (1a) in which the divalent atomic group X includes an ester group is preferable. Considering the length of the molecular chain of the divalent atomic group X, R²The number of carbon atoms is preferably 1-8.
[0048]
[Chemical formula 2]

[0049]
(Wherein R¹Is the same as the above formula (1), and R²Is a branched, aliphatic carbocycle, aromatic carbocycle or an alkylene group which may have a substituent. )
Monomers used for introducing the structural unit of the formula (1) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 4-hydroxycyclohexyl. Hydroxyalkyl acrylates such as (meth) acrylate, 5-hydroxycyclooctyl (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate; hydroxyl group-containing acrylamide such as N-methylol (meth) acrylamide; polyethylene glycol (Meth) acrylate, polypropylene glycol (meth) acrylate; α-hydroxyalkyl acrylate ester such as α-hydroxymethyl acrylate ester; vinyl alcohol, vinyl phenol And the like.
[0050]
The main chain skeleton of the polymer (a) contains a constituent unit having a hydroxyl group as an essential unit, but the main chain skeleton may contain another constituent unit. Examples of the other structural unit include a structural unit having an organic functional group such as an alkyl group or an acidic functional group such as a carboxyl group. As a monomer used for introducing such other structural unit into the main chain skeleton, a compound containing an ethylenically unsaturated bond such as an acrylic compound or an olefin compound can be used.
[0051]
Specific examples of acrylic compounds include acrylic compounds containing a carboxyl group such as (meth) acrylic acid or other acidic functional groups; methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, etc. Alkoxy acrylate; alkoxyalkyl acrylate such as ethoxyethyl (meth) acrylate; alkoxyalkoxyalkyl acrylate such as 2-methoxyethoxyethyl (meth) acrylate; alkoxyalkylene glycol acrylate such as methoxydiethylene glycol (meth) acrylate; N, N-dimethylamino Dialkylaminoalkyl (meth) acrylates such as ethyl (meth) acrylate and N, N-diethylaminoethyl (meth) acrylate; others, acrylonitrile, dimethyl Acrylamide, 2-isocyanate ethyl (meth) acrylate can be exemplified, and also, may also be mentioned (meth) acryloyl-modified silicone, a monomer having a releasing property such as vinyl-modified silicone.
[0052]
Specific examples of the olefinic compound include 2-carboxy-1-butene, 2-carboxy-1-pentene, 2-carboxy-1-hexene, 2-carboxy-1-heptene and other carboxyl groups or other Mention may be made of olefinic compounds containing acidic functional groups.
[0053]
In particular, the structural unit having a bulky group is effective in increasing the glass transition temperature of the cured resin because the structure itself has high heat resistance. As the monomer used for introducing the structural unit having a bulky group into the main chain of the polymer, an acrylic compound having an ethylenically unsaturated bond-containing group and a bulky group is preferably used. Is cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, isobornyl (meth) acrylate, benzyl (meth) acrylate, phenyl (meth) ) Monomers having a cyclic structure such as acrylate, acryloylmorpholine, adamantyl (meth) acrylate, 3-hydroxyadamantyl (meth) acrylate, styrene, α-methylstyrene, 4-vinylpyridine, vinylpyrrolidone, vinylcaprolactone It can be.
[0054]
Moreover, a monomer having a functional group that causes a photodimerization reaction such as N-phenylmaleimide and a monomer having a functional group that causes a photocationic polymerization such as glycidyl (meth) acrylate can be used as a constituent unit.
[0055]
As the copolymerization monomer forming the structural unit having a hydroxyl group, the structural unit having a bulky group, and other structural units, those exemplified above may be used alone or in admixture of two or more.
[0056]
The amount of the structural unit having a hydroxyl group contained in the polymer (a) is adjusted to meet the required degree of photopolymerization, and the total amount of copolymerization monomers used to form the polymer main chain ( When expressed in terms of the ratio of the amount of the hydroxyl group-containing monomer to the total amount charged), it is usually preferred to contain 5 to 90 mol%, particularly 10 to 60 mol%. When the proportion of the structural unit having a hydroxyl group is too small, the amount of the photopolymerizable functional group to be finally introduced into the photocurable resin is reduced, so that the crosslinking density tends to be insufficient. Since the amount of the urethane bond structure formed with the introduction of the functional group is also reduced, the photocurable resin is likely to have insufficient thermoplasticity before curing and flexibility after curing. On the other hand, when the proportion of the structural unit having a hydroxyl group is too large, there are disadvantages such as gelation during synthesis.
[0057]
The structural unit having a bulky group is mainly adjusted in consideration of the thermoplasticity before curing of the photocurable resin and the flexibility after curing, and is the total amount of copolymerization monomers for forming the main chain of the polymer. When expressed as a ratio of the charged amount of the monomer containing a bulky group to the amount used (total charged amount), it is usually preferably 0 to 90 mol%, particularly preferably 5 to 80 mol%. When the proportion of the structural unit having a bulky group is too small, the finally obtained photocurable resin tends to have insufficient blocking resistance before curing and heat resistance after curing. On the other hand, when the proportion of the structural unit having a bulky group is too large, there is an inconvenience that the thermoplasticity before curing of the finally obtained photocurable resin is lowered.
[0058]
Examples of the polymer (a) include the following formula (2):
[0059]
[Chemical Formula 3]

[0060]
(In the formula, Z represents a group for modifying the photocurable resin, and preferably a bulky cyclic structure group.^ThreeEach independently represents a hydrogen atom or a methyl group, R^FourRepresents a hydrocarbon group having 1 to 20 carbon atoms, R^FiveRepresents a linear or branched alkylene group. When the total of l (el), m, n, and o (o) is 100, l is an integer from 0 to 90, m is from 0 to 80, n is from 0 to 50, and o is an integer from 5 to 90. )
The polymer of the structure represented by these can be illustrated.
[0061]
As a preferable example in the polymer represented by the formula (2), 0 to 90 mol of methyl methacrylate and 0 to 80 mol of vinyl-based or acrylic monomer (for example, isobornyl methacrylate) having a bulky group. And 0 to 50 mol of methacrylic acid and 10 to 80 mol of 2-hydroxyethyl methacrylate can be exemplified.
[0062]
The isocyanate compound (b) is an isocyanate compound having at least two isocyanate groups in one molecule and capable of urethane-bonding with the hydroxyl groups of the polymer (a) and the polymerizable compound (c). Examples of such isocyanate compounds include tetramethylene diisocyanate, hexamethylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, 3 , 3-dimethyl-4,4-diphenylene isocyanate, isophorone diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, 1,3-bis (α α- dimethyl isocyanate methyl) benzene, trimethyl hexamethylene diisocyanate, hydrogenated xylylene diisocyanate and the like.
[0063]
In addition, isocyanate compounds represented by the following formulas (3a) to (3g) can also be used.
[0064]
[Formula 4]

[Chemical formula 5]

[0065]
These isocyanate compounds can be used alone or in admixture of two or more. Among these, isophorone diisocyanate is a compound represented by the following formula (4), and is preferably used from the viewpoint of the flexibility of the resin and the adhesiveness with an adjacent layer.
[0066]
[Chemical 6]

[0067]
The polymerizable compound (c) includes one or more photopolymerizable functional groups to be introduced into the polymer (a), and a hydroxyl group for forming a urethane bond with the isocyanate group of the isocyanate compound (b). It is a compound which has this.
[0068]
The photopolymerizable functional group in the polymerizable compound (c) is a functional group that undergoes a polymerization reaction by light irradiation and can form a crosslink between the molecules of the photocurable resin, and is directly activated by light irradiation to photopolymerize. The polymerization reaction may be initiated or accelerated by the action of active species generated from the photopolymerization initiator when irradiated with light in the presence of a photopolymerizable functional group and a photopolymerization initiator. There may be. In the present invention, light includes not only electromagnetic waves having wavelengths in the visible and invisible regions but also radiation, and the radiation includes, for example, microwaves and electron beams.
[0069]
Examples of the photopolymerizable functional group include those having radical photopolymerization reactivity such as an ethylenic unsaturated bond (typically an ethylenic double bond), and a photocation such as a cyclic ether group such as an epoxy group. Those having polymerization reactivity, those having photoanion polymerization reactivity, those having photodimerization reactivity, and the like are applicable. Among these, an ethylenic double bond is preferable. The ethylenic double bond may be any of (meth) acryloyl group, vinyl group, allyl group and the like, and (meth) acryloyl group is particularly preferable.
[0070]
Examples of the compound having a (meth) acryloyl group together with a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxycyclohexyl (meth) acrylate, and 5-hydroxycyclooctyl (meth). Acrylate, compounds having only one (meth) acryloyl group such as 2-hydroxy-3-phenyloxypropyl (meth) acrylate; and trimethylolpropane diacrylate, pentaerythritol triacrylate, dipentaerythritol monohydroxypentaacrylate (Meth) acryloyl groups such as oxyethyl di (meth) acrylate, isocyanurate, glycerol (meth) acrylates, polyethylene glycol (meth) acrylates Compounds having two or more can be exemplified.
[0071]
Among these, since the compound having two or more (meth) acryloyl groups can introduce a plurality of (meth) acryloyl groups with respect to each hydroxyl group contained in the polymer (a), the crosslinking density of the photocurable resin Can be sufficiently increased.
[0072]
When the photocurable resin according to the present invention is produced, when the polymer (a), the isocyanate compound (b) and the polymerizable compound (c) are mixed and reacted at one time, one molecule of the isocyanate compound (b). It is difficult to obtain the molecular structure as described above, because all of the isocyanate groups present therein have a side reaction that reacts only with the polymer (a) or only with the polymerizable compound (c). Therefore, in order to produce the photocurable resin according to the present invention, first, a polymer (a) containing a structural unit having a hydroxyl group in the main chain skeleton, and an isocyanate compound (b) and a polymerizable compound (c). It is preferable that the adduct (bc) is separately produced, and then the adduct (bc) is reacted with the polymer (a).
[0073]
The polymerization solvent used for producing the polymer (a) is preferably a solvent having no active hydrogen such as a hydroxyl group or an amino group. For example, ethers such as tetrahydrofuran; diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol Examples include glycol ethers such as methyl ethyl ether, cellosolv esters such as methyl cellosolve acetate, propylene glycol monomethyl ether acetate, and 3-methoxybutyl acetate. Aromatic hydrocarbons, ketones, esters, etc. should also be used. Can do.
[0074]
As a polymerization initiator used for producing the polymer (a), those generally known as radical polymerization initiators can be used. Specific examples thereof include 2,2′-azobisisobutyronitrile, 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobis- (4-methoxy-2,4). Nitrile azo compounds (nitrile azo polymerization initiators) such as dimethylvaleronitrile); dimethyl 2,2′-azobis (2-methylpropionate), 2,2′-azobis (2,4,4- Non-nitrile azo compounds (non-nitrile azo polymerization initiators) such as trimethylpentane); t-hexyl peroxypivalate, tert-butyl peroxypivalate, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, Lauroyl peroxide, stearoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexano Succinic peroxide, 2,5-dimethyl-2,5-di (2-ethylhexanoylperoxy) hexane, 1-cyclohexyl-1-methylethylperoxy 2-ethylhexanoate, t-hexylperoxy-2 -Organic peroxides (peroxide-based polymerization initiators) such as ethylhexanoate, 4-methylbenzoyl peroxide, benzoyl peroxide, 1,1'-bis- (tert-butylperoxy) cyclohexane; and hydrogen peroxide It is done. When a peroxide is used as the radical polymerization initiator, it may be used as a redox polymerization initiator in combination with a reducing agent.
[0075]
In the production of the polymer (a), a molecular weight regulator can be used to adjust the weight average molecular weight, such as halogenated hydrocarbons such as chloroform and carbon tetrabromide; n-hexyl mercaptan, n -Mercaptans such as octyl mercaptan, n-dodecyl mercaptan, tert-dodecyl mercaptan, thioglycolic acid; xanthogens such as dimethylxanthogen disulfide and diisopropylxanthogen disulfide; terpinolene, α-methylstyrene dimer and the like.
[0076]
The polymer (a) may be either a random copolymer or a block copolymer. In the case of producing a random copolymer, the blended composition composed of the above monomers and catalysts is dropped into a polymerization tank containing a solvent over a period of 2 to 5 hours at a temperature of 80 to 110 ° C., and aged. The polymer (a) can be obtained by polymerization.
[0077]
The adduct (bc) obtained by reacting the isocyanate compound (b) and the polymerizable compound (c) can react with the hydroxyl group of the polymer (a) to form a urethane bond in the molecule. It is sufficient if one isocyanate group remains. Therefore, when a diisocyanate compound is used as the isocyanate compound (b) and a compound having only one hydroxyl group in the molecule is used as the polymerizable compound (c), the isocyanate compound (b) and the polymerizable compound (c) are charged. It is preferred to prepare an adduct of about 1: 1 mol with the amount being about equimolar.
[0078]
If the amount of the polymerizable compound (c) added to the isocyanate compound (b) is too large, the isocyanate group is consumed excessively, and there is a disadvantage that by-products that cannot react with the hydroxyl group of the polymer (a) increase. . On the other hand, when the addition amount of the polymerizable compound (c) to the isocyanate compound (b) is too small, there is a disadvantage that the yield of the adduct (bc) is lowered.
[0079]
The reaction between the polymer (a) and the adduct (bc) is dissolved in a solvent capable of dissolving the polymer (a), for example, a solvent such as toluene, ketone, cellosolve acetate, or dimethyl sulfoxide. While the solution is stirred, the adduct (bc) is dropped and reacted to react the isocyanate group in the adduct (bc) with the hydroxyl group of the polymer (a) to form a urethane bond. As a result, a photopolymerizable functional group can be introduced into the polymer (a) via the urethane bond and the urethane bond in the adduct (bc). The amount of the adduct (bc) used in this case is the ratio of the structural unit having a hydroxyl group of the polymer (a) to the adduct (bc), and is added per mole of the structural unit having a hydroxyl group. The amount of the product (bc) is in the range of 0.1 to 10 mol, preferably 0.5 to 5 mol. In the case where an adduct (bc) having an equivalent amount or more than the hydroxyl group in the polymer (a) is used and the polymer (a) contains a carboxyl group, the adduct (bc ) May also react with the carboxyl group in the polymer (a) to form an amide bond.
[0080]
In the present invention, the adduct (bc) is all urethane-bonded to the hydroxyl group of the polymer (a) to form a photocurable resin, and the addition is not bonded to the hydroxyl group of the polymer (a). It is preferable that the product (bc) and the polymerizable compound (c) are not mixed in the reaction product, but these adduct (bc) and the polymerizable compound (c) are photopolymerizable functional groups. Since it functions as a monomer having a plurality of groups and can form a cross-linking bond with the photo-curable resin according to the present invention, it may coexist with the photo-curable resin as long as it is a certain amount. The effect which raises a density and improves the coating-film physical property of a cured resin layer is acquired. Therefore, since the photocurable resin obtained by the method of reacting the adduct (bc) with the polymer (a) has little adverse effect due to by-products or unreacted substances, the uneven pattern is present even in a state where these remain mixed. It can be used as a forming material, and is advantageous in that it saves the labor of purification.
[0081]
The photocurable resin according to the present invention preferably has a polystyrene equivalent weight average molecular weight of 10,000 to 500,000. When the molecular weight is less than 10,000, not only a sufficient film forming property cannot be obtained, but also blocking tends to occur when the film is wound and stored at room temperature after coating. On the other hand, when the molecular weight exceeds 500,000, the moldability is deteriorated because it is difficult to soften.
[0082]
Next, the photocurable resin composition according to the present invention will be described. The photocurable resin composition according to the present invention contains the photocurable resin according to the present invention and a release agent as essential components.
[0083]
As described above, the photocurable resin contained in the photocurable resin composition according to the present invention exhibits excellent uneven pattern forming ability and processability before curing, and excellent coating film properties after curing. To demonstrate. Therefore, the photocurable resin composition according to the present invention can be replicated with high accuracy even with a very complicated fine uneven pattern, excellent in continuous productivity during replication, and further, strength, hardness, heat resistance, Fine concavo-convex pattern-forming layer with excellent physical properties such as scratch resistance, water resistance, chemical resistance, adhesion to the surface to be coated (typically a base material), and flexibility to follow the bending and expansion / contraction of the base material Can be formed.
[0084]
In particular, when a polymerizable compound (c) having two or more photopolymerizable functional groups in one molecule is used, a large amount of photopolymerizable functional groups are introduced into the photocurable resin as described above. Therefore, the crosslinking density of the photocurable resin composition becomes very large, and the effect of improving various physical properties after curing is high.
[0085]
Among various physical properties after curing, heat resistance and durability (abrasion resistance, chemical resistance, water resistance) are improved by increasing the crosslink density, and even when exposed to high heat, friction or solvent, Less likely to deform, disappear, or damage.
[0086]
Moreover, since the photocurable resin composition according to the present invention further improves the mold release property by blending a release agent as an essential component with respect to the photocurable resin having an excellent mold release property. The stamper pressed against the layer of the photocurable resin composition can be peeled cleanly without causing the surface of the resin layer to be rough or the plate is removed, and a part of the resin remains in the stamper at the time of peeling. Since it has no repetitive embossing property, it is particularly excellent in terms of precision of the fine uneven pattern and continuous productivity.
[0087]
Conventional release agents such as silicone release agents, polyethylene wax, amide wax, Teflon powder (Teflon is a registered trademark), fluorine-type and phosphate-type surfactants. Etc. can be used.
[0088]
Silicone release agents have particularly good release properties from the stamper when combined with the above-mentioned photocurable resin used in the present invention, and the phenomenon of taking a plate hardly occurs. The silicone release agent is a release agent having an organopolysiloxane structure as a basic structure, and examples thereof include unmodified or modified silicone oil, polysiloxane containing trimethylsiloxysilicate, and silicone acrylic resin.
[0089]
The modified silicone oil is obtained by modifying the side chain and / or terminal of polysiloxane, and is classified into a reactive silicone oil and a non-reactive silicone oil. Examples of the reactive silicone oil include amino modification, epoxy modification, carboxyl modification, carbinol modification, methacryl modification, mercapto modification, phenol modification, one-end reactivity, and different functional group modification. Examples of the non-reactive silicone oil include polyether modification, methylstyryl modification, alkyl modification, higher fatty ester modification, hydrophilic special modification, higher alkoxy modification, higher fatty acid modification, and fluorine modification. Two or more of the above-described modification methods can be performed on one polysiloxane molecule.
[0090]
Modified silicone oil is preferred because it has moderate compatibility with the resin. In particular, in the case of using a reactive silicone oil that is reactive with other film forming components blended as necessary in the photocurable resin or the photocurable resin composition, in the cured resin layer Since it is fixed by chemical bonding, problems such as adhesion inhibition, contamination, and deterioration of the cured resin layer are unlikely to occur. In particular, it is effective for improving the adhesion with the vapor deposition layer in the vapor deposition step. In addition, in the case of silicone modified with a photocurable functional group such as (meth) acryloyl-modified silicone, vinyl-modified silicone, etc., since it crosslinks with the photocurable resin composition of the present invention, Excellent.
[0091]
Polysiloxane containing trimethylsiloxysilicic acid is easy to bleed out on the surface and has excellent releasability. Even if it bleeds out to the surface, it has excellent adhesion to the resin, and adhesion to metal deposition and overcoat layer. Is also preferred because of its superiority.
[0092]
In addition to the above (meth) acryloyl-modified silicone oil, an acrylic resin obtained by copolymerizing or grafting a silicon-containing monomer can be used as the silicone-based acrylic resin.
[0093]
The said mold release agent can be added only in 1 type or in combination of 2 or more types.
[0094]
The release agent is preferably blended at a ratio of 0.1 to 30% by weight in the total solid content of the photocurable resin composition. When the ratio of the release agent is less than the above range, the release property between the stamper and the photocurable resin layer tends to be insufficient. On the other hand, if the ratio of the release agent exceeds the above range, a problem of surface roughness of the coating surface due to repelling at the time of coating of the composition may occur, or the substrate itself and the adjacent layer in the product, for example, adhesion of the vapor deposition layer This is not preferable from the viewpoints of inhibiting the properties and causing film breakage or the like (film strength becomes too weak) during transfer.
[0095]
In the case where the photocurable resin composition according to the present invention contains inorganic fine particles that can be dispersed in a colloidal form in an organic solvent, it is preferable from the viewpoint of improving moldability, shape maintenance, and releasability. .
[0096]
As the inorganic fine particles that can be dispersed in an organic solvent in a colloidal form, if a part of the inorganic fine particles is a hydroxide and has a structure in which water is adsorbed and hydrated, a photocurable resin composition This is preferable because it can be easily dispersed in a colloidal form in an organic solvent which is a diluting solvent for the product. Further, when the surface of the inorganic fine particles is subjected to a hydrophobic treatment, it becomes easy to disperse in a colloidal form. The inorganic fine particles can be imparted with hydrophobicity by, for example, surface treatment with an organic low molecular component such as organic amine or organic carboxylic acid.
[0097]
In addition, inorganic fine particles having a so-called ultrafine particle size are used in order to ensure sufficient transparency of the coating film. Here, “ultrafine particles” are particles of submicron order, and generally mean particles having a particle diameter smaller than particles having a particle diameter of several μm to several hundred μm, which are generally called “fine particles”. ing. The specific size of the inorganic fine particles used in the present invention varies depending on the use and grade of the optical article to which the photocurable resin composition is applied, but generally the primary particle diameter is in the range of 1 nm to 300 nm. It is preferable to use one. If the primary particle size is less than 1 nm, it becomes difficult to sufficiently improve the moldability, shape maintenance and mold release properties of the resin composition. On the other hand, if the primary particle size exceeds 300 nm, the resin has transparency. Depending on the use of the optical article, the transparency may be insufficient.
[0098]
Specific examples of inorganic fine particles include SiO₂TiO₂, ZrO₂, SnO₂, Al₂O_ThreeAmong these, it is preferable to select and use one having a particle size on the order of submicron, which can be colloidally dispersed as described above. Particularly, colloidal silica ( SiO₂It is preferable to use fine particles.
[0099]
The inorganic fine particles are preferably blended in a proportion of 1 to 70% by weight and particularly preferably in a proportion of 1 to 50% by weight in the total solid content of the photocurable resin composition. When the proportion of the inorganic fine particles is less than 1% by weight, it becomes difficult to sufficiently improve the moldability, shape maintaining property and releasability of the resin composition, while when the proportion of the inorganic fine particles exceeds 70% by weight. The brittleness becomes remarkable and it becomes difficult to obtain sufficient strength and surface hardness after exposure and curing.
[0100]
The inorganic fine particles may have any shape, but a bulky shape such as a needle shape is preferable. As the acicular fine particles, for example, those having a thickness of 5 to 20 nm and a length of 40 to 300 nm can be used.
[0101]
When a reactive functional group such as a (meth) acryloyl group is introduced on the surface of the inorganic fine particle, and this is used, a chemical bond such as a covalent bond is formed between the fine particles or with the curable component of the photocurable resin. Since it can be formed, various physical properties, particularly strength and hardness of the coating film are improved.
[0102]
When such inorganic fine particles are blended in the photocurable resin composition, a press stamper is pressed on the photocurable resin layer made of the photocurable resin composition to form a fine concavo-convex pattern. It is possible to prevent the fine uneven pattern from being rounded and out of shape due to the elasticity of the resin composition itself during the process such as the exposure process and the vapor deposition process after the removal. Also, by adding the inorganic fine particles, the releasability of the photocurable resin composition is improved, and the resin composition is less likely to adhere to the cavity inner surface of the stamper when the stamper pressed against the photocurable resin layer is removed. .
[0103]
This makes it possible to accurately reproduce a fine concavo-convex pattern having a concavo-convex width (pitch) of about 10 μm or less or a concavo-convex depth of 2 μm or less, as required, and has a more advanced optical function. Even when a complicated fine concavo-convex pattern, for example, a pattern in which the width (pitch) of the concavo-convex pattern is about 200 nm or less or a depth (depth / width) with respect to the width is ½ or more is reproduced, The fine uneven pattern forming material can be poured into every corner of the cavity at the time of pressure contact, and the plate is not taken off when the stamper is peeled off, and the pattern collapse after removing the stamper is also difficult to occur. Mass production with high accuracy and embossing becomes possible.
[0104]
Furthermore, the inorganic fine particles also have an effect of reducing the tackiness of the photocurable resin composition, and the intermediate laminate before forming the photocurable resin layer on the base film and pressing the press stamper is wound into a roll. Even if it takes, there exists an advantage that it becomes difficult to produce blocking.
[0105]
The photocurable resin composition of the present invention includes an auxiliary binder component such as a non-reactive or cross-linking reactive binder polymer for the purpose of adjusting the physical properties of the photocurable resin composition before or after curing. Alternatively, a monofunctional or polyfunctional photopolymerizable monomer or oligomer may be blended. When the crosslinking reactive binder component is used supplementarily, the same reaction type as that of the photocurable resin is usually used. For example, if the photocurable resin is photoradical polymerizable, the auxiliary binder is used. Components are also combined with those having radical photopolymerization.
[0106]
A polyfunctional monomer or polyfunctional oligomer, that is, a monomer or oligomer having two or more photopolymerizable functional groups in one molecule is preferably used for the purpose of further increasing the crosslinking density of the photocurable resin composition.
[0107]
Bifunctional monomer having photo-radical polymerizability, oligomers include polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate Trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, aliphatic tri (meth) acrylate, etc. as trifunctional monomers and oligomers; Pentaerythritol tetra (meth) as tetrafunctional monomers and oligomers Examples include acrylate, ditrimethylolpropane tetra (meth) acrylate, and aliphatic tetra (meth) acrylate. 5 or more functional radically polymerizable monomers and oligomers such as dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, etc .; in addition, polyester acrylate, urethane acrylate, polyether acrylate, epoxy acrylate, etc. Examples of various acrylate oligomers include monomers or oligomers having a bulky structure such as a phosphazene skeleton, an adamantane skeleton, a cardo skeleton, and a norbornene skeleton. The number of functional groups is not particularly limited, but if the number of functional groups is less than 3, the heat resistance tends to decrease, and if it is 20 or more, the flexibility tends to decrease. Is preferred.
[0108]
Polyfunctional photo-radically polymerizable monomers or oligomers include the above (meth) acrylates, vinyl compounds such as divinylbenzene, diethylene glycol bisallyl carbonate, trimethylolpropane diallyl, diallyl phthalate, dimethacryl phthalate, diallyl isophthalate An allyl compound such as can also be used.
[0109]
When using a photocationic polymerization reaction, a monomer having one or more epoxy groups in the molecule, a monomer having one or more epoxy groups and one or more (meth) acryloyl groups in the molecule, an oxetane compound, etc. Can be used.
[0110]
The monomer or oligomer is used in an amount of about 5 to 80 parts by weight, preferably about 10 to 40 parts by weight per 100 parts by weight of the photocurable resin. If the amount of the monomer or oligomer used is less than the above range, it is often insufficient to improve the strength, heat resistance, scratch resistance, water resistance, chemical resistance and adhesion to the substrate of the resulting cured resin layer. . On the other hand, if the amount of the monomer or oligomer used exceeds the above range, the surface tack becomes high, causing blocking, or repeated due to a part of the material remaining on the plate (press stamper) when the hologram is copied (press stamper). It is easy to cause problems such as a decrease in embossability.
[0111]
The photocurable resin composition according to the present invention can be prepared by further blending other components such as a photopolymerization initiator, a polymerization inhibitor, and an organic metal coupling agent as necessary.
[0112]
A photopolymerization initiator that has activity with respect to the wavelength of the light source to be used and generates an appropriate active species depending on the reaction mode of the binder or monomer (for example, radical polymerization or cationic polymerization) Is used.
[0113]
Examples of the photo radical initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, α-methylbenzoin, α-phenylbenzoin, anthraquinone, methylanthraquinone, acetophenone, 2,2-diethoxyacetophenone, 2, 2-dimethoxy-2-phenylacetone, benzyldiacetylacetophenone, benzophenone, p-chlorobenzophenone, 2-hydroxy-2-methylpropiophenone, diphenyldisulfide, tetramethylthiuram sulfide, α-chloromethylnaphthalene, anthracene, hexachlorobutadiene, Pentachlorobutadiene, Michler's ketone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, benzyldimethylket Bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanone-1,2-hydroxy-2-methyl- 1-phenylpropan-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, and the like.
[0114]
Examples of the photocation initiator include aromatic diazonium salts, aromatic iodonium salts, aromatic sulfonium salts, aromatic phosphonium salts, mixed ligand metal salts, and the like.
[0115]
Examples of photoanion initiators include 1,10-diaminodecane, 4,4'-trimethylenedipiperidine, carbamates and derivatives thereof, cobalt-amine complexes, aminooxyiminos, ammonium borates and the like. be able to.
[0116]
The photopolymerization initiator is preferably blended at a ratio of 0.5 to 10% by weight with respect to the total solid content of the photocurable resin composition. A photoinitiator may be used individually by 1 type and may be used in combination of 2 or more type.
[0117]
In order to improve the storage stability, a polymerization inhibitor may be blended in the photocurable resin composition of the present invention. As a polymerization inhibitor, for example, phenols such as hydroquinone, t-butylhydroquinone, catechol and hydroquinone monomethyl ether; quinones such as benzoquinone and diphenylbenzoquinone; phenothiazines; coppers and the like can be used. The polymerization inhibitor is preferably blended at a ratio of 0.1 to 10% by weight with respect to the total solid content of the photocurable resin composition.
[0118]
An organic metal coupling agent may be added to the photocurable resin composition in order to increase the heat resistance, strength, or adhesion of the surface structure having a fine concavo-convex pattern to the metal deposition layer. In addition, the organometallic coupling agent is effective because it has an effect of promoting the thermosetting reaction. As the organometallic coupling agent, for example, various coupling agents such as a silane coupling agent, a titanium coupling agent, a zirconium coupling agent, an aluminum coupling agent, and a tin coupling agent can be used.
[0119]
Examples of the silane coupling agent include vinyl silanes such as vinyltrichlorosilane, vinyltris (β-methoxyethoxy) silane, vinyltriethoxysilane, and vinyltrimethoxysilane; γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyl Acrylic silanes such as dimethoxysilane; epoxy silanes such as β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane; N-β -(Aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxy Aminosilanes such as silane; and, as other silane coupling agents, .gamma.-mercaptopropyltrimethoxysilane, .gamma.-chloropropyl methyl dimethoxy silane, .gamma.-chloropropyl methyl diethoxy silane and the like.
[0120]
Examples of titanium coupling agents include isopropyl triisostearoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl tris (dioctyl pyrophosphate) titanate, tetraisopropyl bis (dioctyl phosphite) titanate, tetraoctyl bis (ditridecyl phosphite) Titanate, tetra (2,2-diallyloxymethyl) bis (ditridecyl) phosphite titanate, bis (dioctylpyrophosphate) oxyacetate titanate, bis (dioctylpyrophosphate) ethylene titanate, isopropyltrioctanoyl titanate, isopropyldimethacrylisostearoyl Titanate, isopropyl isostearoyl diacryl titanate, isop Pirutori (dioctyl phosphate) titanate, isopropyl tricumylphenyl titanate, isopropyl tri (N- aminoethyl-aminoethyl) titanate, dicumyl phenyloxy acetate titanate, diisostearoyl ethylene titanate.
[0121]
Examples of the zirconium coupling agent include tetra-n-propoxyzirconium, tetra-butoxyzirconium, zirconium tetraacetylacetonate, zirconium dibutoxybis (acetylacetonate), zirconium tributoxyethyl acetoacetate, zirconium butoxyacetylacetonate bis. (Ethyl acetoacetate) and the like.
[0122]
Examples of the aluminum coupling agent include aluminum isopropylate, monosec-butoxyaluminum diisopropylate, aluminum sec-butyrate, aluminum ethylate, ethylacetoacetate aluminum diisopropylate, aluminum tris (ethylacetoacetate), alkylacetate Acetate aluminum diisopropylate, aluminum monoacetylacetonate bis (ethyl acetoacetate), aluminum tris (acetylacetoacetate) and the like can be mentioned.
[0123]
The organometallic coupling agent is preferably blended at a ratio of 0.1 to 15% by weight in the total solid content of the photocurable resin composition. When the ratio of the organometallic coupling agent is less than the above range, the effect of imparting heat resistance, strength, and adhesion to the deposited layer is insufficient. On the other hand, when the ratio of the organometallic coupling agent exceeds the above range, the stability and film formability of the composition may be impaired.
[0124]
The photocurable resin composition of the present invention is usually prepared in the state of a coating solution using a diluting solvent and used for forming a fine uneven pattern. Each material as described above is acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, benzene, toluene, xylene, chlorobenzene, tetrahydrofuran, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, ethyl acetate, 1,4- A coating solution of the photocurable resin composition according to the present invention can be prepared by dissolving and dispersing in dioxane, 1,2-dichloroethane, dichloromethane, chloroform, methanol, ethanol, isopropanol, or a mixed solvent thereof. it can. The coating solution is usually adjusted so that the solid content concentration is about 10 to 50% by weight.
[0125]
In addition, when preparing a photocurable resin composition, when using the photocurable resin obtained by the method with which an adduct (bc) is made to react with a polymer (a), as above-mentioned, it is a subsidiary. Even if the reaction liquid obtained by reacting the adduct (bc) with the polymer (a) is mixed with other materials as it is because there is little adverse effect due to living organisms or unreacted substances, a photocurable resin composition can be prepared. Well, even if a free adduct (bc) and an unreacted polymerizable compound (c) are mixed in the photocurable resin composition, these function as a polyfunctional monomer and improve the crosslinking density. An effect is obtained.
[0126]
The photocurable resin composition obtained as described above is applied to the surface of a support such as a base film, and dried as necessary to form a layer of the photocurable resin composition (a fine uneven pattern forming layer). Forming a concavo-convex pattern receptor, embossing by pressing a stamper on the surface of the fine concavo-convex pattern formation layer of the concavo-convex pattern receiver, and exposing and curing the fine concavo-convex pattern formation layer to optically A fine concavo-convex pattern having a function can be formed and used as an optical article or a stamper.
[0127]
In addition, this photocurable resin composition makes it possible to mass-produce a complicated fine concavo-convex pattern having the above-described advanced optical function with high accuracy by embossing.
[0128]
In the following, a method for forming a fine uneven pattern and a fine uneven pattern transfer foil using the photocurable resin composition will be described.
[0129]
Before and after forming the fine concavo-convex pattern forming layer on the support by applying the photocurable resin composition according to the present invention on the support, or before and after forming the fine concavo-convex pattern on the fine concavo-convex pattern forming layer, If necessary, other layers such as an anchor layer, a release layer, a metal thin film layer, an overcoat layer, a pressure-sensitive or heat-sensitive adhesive layer may be formed on the support or the fine uneven pattern forming layer.
[0130]
The fine concavo-convex pattern forming layer may be cured in a state where the stamper is pressed, but may be exposed and heated after the stamper is removed. The latter method is excellent in continuous productivity because the stamper is removed before the fine uneven pattern forming layer is transferred to the curing process, and the removed stamper can be continuously used in the embossing process.
[0131]
Further, in the present invention, utilizing the fact that the photocurable resin composition is excellent in film formability and releasability, an intermediate laminate in which a fine uneven pattern forming layer is formed on a base film in a roll shape. It is also possible to take up and store temporarily, transport to another location, rewind, stamping and curing.
[0132]
Furthermore, the intermediate laminate that has been stamped and cured is wound up into a roll and temporarily stored, transported to another place and rewound, and if necessary, an additional photocuring step is performed to sufficiently cure, Alternatively, a metal thin film, an overcoat layer, a pressure-sensitive or heat-sensitive adhesive layer, or the like can be formed as necessary.
[0133]
The concavo-convex pattern receptor may be a final product to which a surface structure of a fine concavo-convex pattern is to be imparted, but may be an intermediate transfer medium. That is, in the present invention, a transfer foil (uneven pattern receiver) is prepared by applying the above-mentioned photocurable resin composition to a first support to form a fine uneven pattern forming layer, and the transfer foil has a fine structure. After forming a fine uneven pattern on the uneven pattern forming layer and curing the fine uneven pattern forming layer, it is possible to transfer it onto the second support (final product). When the transfer foil is used, there is an advantage that it is not necessary to directly emboss the surface of the final product, or a large amount of fine uneven patterns can be formed in advance on the transfer foil. Forming a fine concavo-convex pattern by continuous transfer on the surface of an article that is difficult to directly emboss, such as a surface-shaped article, or on a support such as glass, plastic, or metal plate that cannot be rolled up Is also possible.
[0134]
In the present invention, the fine concavo-convex pattern transfer foil is composed of at least the photocurable resin composition according to the present invention on the first support, and peels from the first support to form the second support. It is a laminate provided with a fine concavo-convex pattern forming layer in a state capable of being transferred, and if necessary, in addition to the fine concavo-convex pattern forming layer, a peeling layer, a reflective layer, an adhesive layer or other layers 1 or 2 or more can be provided. For example, as shown in FIG. 1, the transfer foil 1 may have a configuration in which a peeling layer 3, a fine uneven pattern forming layer 4, a reflective layer 5, and an adhesive layer 6 are sequentially laminated on a support 2.
[0135]
As a support for producing a transfer foil, a flexible base film is usually used, and a plastic film such as polyethylene terephthalate is suitable in terms of strength and heat resistance, but is not limited to a plastic film. In addition, it may not be flexible, and other materials such as a metal plate and paper may be used as the support. Further, when using an impregnated support such as paper, it may be formed in a state in which the fine uneven pattern forming layer is impregnated in the support structure, and even in such a state, it is provided on the support. It is contained in one form of the formed fine uneven | corrugated pattern formation layer. In addition, a continuous film may be used as the base film in consideration of mass productivity of fine concavo-convex patterns such as holograms, but a sheet-like base film may be used.
[0136]
The release layer is provided on the lower layer of the fine concavo-convex pattern forming layer as necessary for the purpose of improving the peelability and tearability of the transfer foil, and fine concavo-convex from the transfer foil to some transfer surface (second support). This is the layer that becomes the outermost surface after being transferred together with the pattern forming layer. As the release layer, for example, only one kind selected from acrylic resin, polyester resin, polyvinyl chloride resin, cellulose resin, silicone resin, chlorinated rubber, casein, various surfactants, metal oxides, etc., alone or 2 More than seeds can be selected and mixed for use. Or what added these as an additive to the photocurable resin composition of this invention used for a fine uneven | corrugated pattern formation layer can also be used as a peeling layer.
[0137]
The reflective layer is provided on the fine concavo-convex pattern when, for example, a relief hologram is formed. The reflective layer can be formed of a metal thin film or a high refractive index film formed using a coating liquid of a high refractive index material.
[0138]
The metal thin film is, for example, a metal such as Cr, Ti, Fe, Co, Ni, Cu, Ag, Au, Ge, Al, Mg, Sb, Pb, Pd, Cd, Bi, Sn, Se, In, Ga, and Rb. And oxides, nitrides, sulfides, and the like thereof, or a mixture of two or more of them, and can be formed by a method such as chemical vapor deposition or physical vapor deposition. The high refractive index material film is, for example, coating of a coating liquid in which a high refractive index filler is dispersed, coating of a colloidal solution of gold or silver, or hydrolytic polycondensation reaction of an organometallic compound represented by a sol-gel reaction. It can be formed by forming a coating film by the method.
[0139]
The adhesive layer is used for the purpose of improving the transferability of the fine concavo-convex pattern forming layer and the adhesion to the transfer target surface after transfer, or the surface of the fine concavo-convex pattern forming layer after embossing is used as a reflective film or the like. In the case of covering with a protective film, it is provided on the outermost surface of the fine concavo-convex pattern forming layer for the purpose of improving adhesion to these layers, and is a layer that becomes the lowermost layer after being transferred together with the fine concavo-convex pattern forming layer. .
[0140]
As the adhesive layer, a known heat-sensitive adhesive resin can be used. For example, rubber systems such as polyisoprene rubber, polyisobutylene rubber, styrene butadiene rubber; poly (meth) methyl acrylate, poly (meth) ethyl acrylate, poly (meth) acrylate, poly (meth) acrylate, (Meth) acrylic acid esters such as poly (meth) acrylic acid-2-ethylhexyl; polyvinyl ethers such as polyisobutyl ether; polyvinyl chlorides such as polyvinyl acetate and vinyl chloride-vinyl acetate copolymer; polyacrylamide Polyamides such as polymethylolacrylamide; Vinyl chlorides such as polyvinyl chloride; Other vinyls such as polyvinyl butyral, vinyl acetate / octyl acrylate, vinyl acetate / butyl acrylate, vinylidene chloride / butyl acrylate; polystyrene, etc. Aromatic vinyl series of; and Li chloride olefin and the like, can be used alone or in combination of two or more select only one among these.
[0141]
The fine concavo-convex pattern forming method of the present invention will be specifically described by taking a relief hologram transfer foil as an example. In addition, the code | symbol used is for referring FIG. First, the base film 2 made of continuous plastic such as polyethylene terephthalate is fed out from the roll stock. The coating liquid of the release agent was applied onto the unrolled base film using a roll coater, and then set to a temperature at which the organic solvent contained in the coating liquid was scattered, for example, l00 to 165 ° C. The release layer 3 is formed by introducing the powder into a heating furnace for about 0.1 to 1 minute and drying it. On this peeling layer 3, the fine uneven | corrugated pattern formation material which consists of a photocurable resin composition is continuously apply | coated using a roll coater, Then, the temperature which the organic solvent contained in a composition scatters, for example, 100 The transfer foil 1 is produced by introducing the fine concavo-convex pattern forming layer 4 into the heating furnace 10 set at ˜165 ° C. for about 0.1 to 1 minute and drying it. As a coating machine other than the roll coater, for example, a curtain coater, a flow coater, a lip coater, a doctor blade coater, a gravure coater or the like can be used. The thickness of the fine uneven pattern forming layer is usually about 0.1 to 5.0 μm. The produced transfer foil 1 is wound up again to form a roll stock, which is stored or transported.
[0142]
Next, the transfer foil 1 is unwound from a roll stock, and a relief hologram stamper is pressed onto the surface of the fine concavo-convex pattern forming layer and embossed to form a fine concavo-convex pattern (not shown).
[0143]
The embossing of the hologram pattern is performed using, for example, a pair of embossing rollers composed of a metal roll and a paper roll with a stamper continuously created from a mother die made using laser light or an electron beam. In a usual manner, for example, a hot roll temperature of 100 to 200 ° C., a press pressure of 5 × 10^Three~ 5x10⁶Perform at Pa. When embossing is performed under the press conditions in this range, the resin temperature of the fine concavo-convex pattern forming layer is adjusted to a temperature in or near 60 to 80 ° C., which is suitable for embossing. When the hot roll temperature is higher than the above range, embossing can be performed at a high speed, but the damage to the base film is increased. Moreover, since it will take time to raise resin temperature when a hot roll temperature is made lower than the said range, an embossing process becomes slow. In addition, as an embossing roller of the duplicating apparatus, a duplication hologram created from a master hologram by resin plate making and pasted on a cylinder can be used.
[0144]
For embossing, single-sided embossing is sufficient, but double-sided embossing may be used. In embossing, it is important to set the temperature of the embossing roll. From the viewpoint of reproducing the embossing shape, it is preferable to emboss at a relatively high temperature and relatively high pressure, but in order to prevent adhesion to the embossing plate. It is preferable to emboss at a relatively low pressure, which is exactly the opposite relationship. In addition, when considering the heat capacity that works effectively, the conveyance speed of the duplicated film is also important. In order to reduce the adhesion of the photocurable resin composition to the embossing roll, the selection of the release agent described above is also important.
[0145]
The photocurable resin layer is embossed, peeled off from the stamper, and then irradiated with light to cure the resin layer. Examples of the light used for curing include high energy ionizing radiation and ultraviolet rays. As the high-energy ionizing radiation source, for example, an electron beam accelerated by an accelerator such as a cockcroft accelerator, a handagraaf accelerator, a linear accelerator, a betatron, or a cyclotron is industrially most conveniently and economically used. However, radiation such as γ rays, X rays, α rays, neutron rays, proton rays emitted from radioisotopes or nuclear reactors can also be used. Examples of the ultraviolet ray source include an ultraviolet fluorescent lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a xenon lamp, a carbon arc lamp, and a solar lamp.
[0146]
After curing, a reflective film such as a metal vapor deposition layer or a transparent protective film for enhancing scratch resistance and contamination resistance may be formed on the fine concavo-convex pattern as necessary. In addition, when a layer such as a reflective film or a protective film is added on the fine uneven pattern forming layer, an adhesive layer may be further added thereon.
[0147]
It is necessary to provide a reflective film on the photocured resin layer. When a metal thin film that reflects light is used as the reflection film, an opaque type hologram is formed. When a reflection film having a refractive index difference from the hologram layer is formed of a transparent substance, the reflection type is formed. A metal thin film such as a reflective film can be formed by a known method such as sublimation, vacuum deposition, sputtering, reactive sputtering, ion plating, or electroplating.
[0148]
For example, Cr, Ti, Fe, Co, Ni, Cu, Ag, Au, Ge, Al, Mg, Sb, Pb, Pd, Cd, Bi, Sn, Se, A thin film formed using a metal such as In, Ga, or Rb and an oxide or nitride thereof alone or in combination of two or more kinds can be used. Among the metal thin films, Al, Cr, Ni, Ag, Au and the like are particularly preferable, and the film thickness is in the range of 1 to 10,000 nm, desirably 20 to 200 nm.
[0149]
As the thin film forming the transparent type hologram, any material can be used as long as it is light transmissive so as to exhibit the hologram effect. For example, a transparent material having a refractive index different from that of the resin of the fine uneven pattern forming layer can be used. The refractive index in this case may be larger or smaller than the refractive index of the resin of the hologram forming layer, but the difference in refractive index is preferably 0.1 or more, more preferably 0.5 or more, and 1.0 or more. Particularly preferred. In addition, a transparent type other than the above includes a metallic reflective film of 20 nm or less. As a transparent type reflective layer preferably used, titanium oxide (TiO 2) is used.₂), Zinc sulfide (ZnS), and the like.
[0150]
The transfer foil in which the fine concavo-convex pattern is formed and cured in this manner on the fine concavo-convex pattern forming layer is wound up again to form a roll stock, which is stored or transported.
[0151]
Next, the transfer foil on which the fine concavo-convex pattern is formed is drawn out from the roll stock, and the transferred surface of the second support is faced and superimposed on the fine concavo-convex pattern forming layer to transfer the hologram. The transfer foil is heated and pressed with a pressure roller or pressure plate from the base film side to melt and adhere, and then the transfer foil is peeled off so that the fine uneven pattern forming layer having the fine uneven pattern is the second support. It is transferred onto the body. The temperature and pressure at the time of transfer are factors related to the pressure method (roll type, stamping type) and pressure method, as well as the material and melting temperature of the support, the melting temperature of the heat-sensitive adhesive, and the heat-sensitive adhesive. Since the conditions vary greatly depending on factors such as the adhesion between the agent and the support material, the conditions are adjusted accordingly.
[0152]
In this way, an optical article comprising a cured resin layer made of a cured product of the photocurable resin composition and having a surface structure on which a fine concavo-convex pattern of a relief hologram is formed is obtained.
[0153]
According to the present invention, a fine concavo-convex pattern comprising a cured product of a photocurable resin composition and having various optical functions is obtained by a method similar to that of the relief hologram or modified as necessary. An optical article provided with a cured resin layer having a formed surface structure can be produced.
[0154]
As optical articles produced by embossing using the photocurable resin composition of the present invention, (1) relief holograms and diffraction gratings used for security applications, such as credit cards, ID cards, gift certificates, banknotes, etc. (2) Relief holograms and diffraction gratings used for graphic arts and design applications, for example, amusement products such as so-called photo clubs or giveaways, packaging, postcards / sealings, novelty goods, etc. (3) An optical element that controls at least one of reflection, transmission, scattering, polarization, condensing, or interference of all rays and / or light of a specific wavelength, such as a reflector, a scattering plate, a polarizing plate, a lens, and a wavelength. (4) Information used as an optical element such as a selection element, an antireflection plate, a birefringent wavelength plate, an optical element having a subwavelength structure, or the like Recording device, for example, it can be cited information recording holograms, optical cards, and the like can be employed not only as an optical disk or the like.
[0155]
The present invention can be applied to applications that control light more complicatedly or more precisely than relief holograms and diffraction gratings. However, when applied to relief holograms and diffraction gratings, the present invention can be used not only to obtain bright holograms but also to obtain complex holograms. Relief holograms and diffraction gratings with simple designs can be formed.
[0156]
Furthermore, according to the present invention, a fine concavo-convex pattern can be formed with very high accuracy. Therefore, a complementary concavo-convex pattern can be duplicated using a fine concavo-convex pattern to be applied to an optical article as a mold and used as a stamper. Is possible.
[0157]
【Example】
A. Production example
A-1 Synthesis of acrylic resin a having hydroxyl group
(Production Example 1)
A 2 liter flask equipped with a condenser, dropping funnel and thermometer was charged with 40 g of toluene and 40 g of methyl ethyl ketone together with an azo polymerization initiator, 21.0 g of 2-hydroxyethyl methacrylate, 58.0 g of methyl methacrylate, and isobornyl. A mixture of 22.5 g of methacrylate, 30 g of toluene, and 20 g of methyl ethyl ketone was dropped with a dropping funnel and reacted at a temperature of 100 ° C. for 8 hours, and then cooled to room temperature to obtain a resin solution of acrylic resin a having a hydroxyl group. It was.
[0158]
A-2 Synthesis of isocyanate group-containing urethane acrylate
(Production Example 2)
A 2 liter flask equipped with a condenser, dropping funnel and thermometer is charged with 120.0 g of methyl ethyl ketone and 33.0 g of isophorone diisocyanate, 55.3 g of glyceryl acrylate methacrylate (trade name: 701A, manufactured by Shin-Nakamura Chemical Co., Ltd.), lauric acid Dibutyltin was added and reacted to obtain a resin solution of isocyanate group-containing urethane acrylate b.
[0159]
(Production Example 3)
The isocyanate group-containing urethane acrylate c was changed to 88.4 g of tetramethylol methane triacrylate (trade name: A-TMM-3-LMN, manufactured by Shin-Nakamura Chemical Co., Ltd.). A resin solution was obtained.
[0160]
B. Examples and Comparative Examples
B-1 Synthesis of photocurable resin
Example 1
45.5 g of the resin solution of the isocyanate group-containing urethanized acrylate b obtained in Production Example 2 is added to 40.0 g of the resin solution of acrylic resin a obtained in Production Example 1, and dibutyltin laurate is used as a catalyst. As an addition reaction. The disappearance of the absorption peak of the isocyanate group was confirmed by IR analysis of the reaction product, and the reaction was completed. An acrylic resin A having a weight average molecular weight (polystyrene conversion) of about 47,000 was obtained.
[0161]
(Example 2)
145.8 g of the resin solution of the isocyanate group-containing urethanized acrylate b obtained in Production Example 2 is added to 40.0 g of the resin solution of acrylic resin a obtained in Production Example 1, and dibutyltin laurate is used as a catalyst. As an addition reaction. The disappearance of the absorption peak of the isocyanate group was confirmed by IR analysis of the reaction product, and the reaction was completed. An acrylic resin B having a weight average molecular weight (polystyrene conversion) of about 40000 was obtained.
[0162]
(Example 3)
82.5 g of the resin solution of the isocyanate group-containing urethanized acrylate c obtained in Production Example 3 is added to 60.0 g of the acrylic resin a resin solution obtained in Production Example 1, and dibutyltin laurate is used as a catalyst. As an addition reaction. The disappearance of the absorption peak of the isocyanate group was confirmed by IR analysis of the reaction product, and the reaction was completed. An acrylic resin C having a weight average molecular weight (polystyrene conversion) of about 172,000 was obtained.
[0163]
B-2 Preparation of photocurable resin composition
Example 4
Each component was mixed according to the following composition, and the photocurable resin composition 1 was obtained.
<Composition of photocurable resin composition 1>
-Acrylic resin A of Example 1: 80 parts by weight (in terms of solid content)
-Urethane acrylate oligomer (trade name: Purple light UV-1700B, manufactured by Nippon Synthetic Chemical Industry): 20 parts by weight
-Silicone release agent (trade name: X-24-8201, manufactured by Shin-Etsu Chemical Co., Ltd.): 5 parts by weight
Photoinitiator (trade name: Irgacure 907, manufactured by Ciba Specialty Chemicals): 5 parts by weight
[0164]
(Example 5)
Each component was mixed according to the following composition, and the photocurable resin composition 1 was obtained.
<Composition of photocurable resin composition 2>
-Acrylic resin B of Example 1: 90 parts by weight (in terms of solid content)
-Silicone release agent (trade name: BYK-371, manufactured by Big Chemie): 5 parts by weight-Photoinitiator (trade name: Irgacure 907, manufactured by Ciba Specialty Chemicals): 5 parts by weight
[0165]
(Example 6)
Each component was mixed according to the following composition, and the photocurable resin composition 3 was obtained.
<Composition of photocurable resin composition 3>
-Acrylic resin C of Example 1: 90 parts by weight (in terms of solid content)
Silicone release agent (trade name: X-21-3056, manufactured by Shin-Etsu Chemical Co., Ltd.): 5 parts by weight
Photoinitiator (trade name: Irgacure 907, manufactured by Ciba Specialty Chemicals): 5 parts by weight
[0166]
(Comparative Example 1)
Each component was mixed according to the following composition, and the comparative composition 1 was obtained.
<Composition of Comparative Composition 1>
-Acrylic resin a (unmodified) in Production Example 1: 80 parts by weight (in terms of solid content)
-Urethane acrylate oligomer (trade name: Purple light UV-1700B, manufactured by Nippon Synthetic Chemical Industry): 20 parts by weight
-Silicone release agent (trade name: X-24-8201, manufactured by Shin-Etsu Chemical Co., Ltd.): 5 parts by weight
[0167]
B-3 Production of label type fine uneven pattern sheet
Each of the resin compositions obtained in the above Examples and Comparative Examples was formed on the easy-adhesive treated surface of a single-sided easy-adhesive treated polyethylene terephthalate film (Diafoil T600E U-36, manufactured by Diafoil Hequist) having a thickness of 50 μm. Coating with a gravure coater, drying at 100 ° C. to volatilize the solvent, and the coating amount on drying is 2 g / m²A photosensitive film for duplication was formed. All of the photosensitive films for duplication, including those prepared using the resin compositions obtained in the comparative examples, had no surface tack and did not cause blocking in the wound state.
[0168]
Next, a press stamper produced from a diffraction grating (pitch 0.8 μm) formed by electron beam drawing was placed on the embossing roller of the replication apparatus. The photosensitive film for duplication was set on the paper feeding side of the duplicating apparatus, the heating roller was set to 150 ° C. and heated and pressed, and peeled from the embossing roller to form a diffraction grating pattern. None of the replicated products, including those produced using the resin compositions obtained in the comparative examples, caused plate removal and had good release properties.
[0169]
Next, ultraviolet light was irradiated from a high-pressure mercury lamp to photocur the photosensitive film for duplication, and subsequently aluminum was deposited by vacuum deposition to produce a diffraction grating film (fine concavo-convex pattern sheet). The diffraction grating films, including those prepared using the resin compositions obtained in the comparative examples, were all glossy and were good with no darkened or missing parts.
[0170]
B-4 evaluation
(1) Heat resistance of diffraction grating film
The diffraction grating film was placed in an oven at 100 ° C. for 5 hours, and the gloss and brightness of the diffraction grating were compared before and after heating and evaluated according to the following criteria. The results are shown in Table 1.
<Evaluation criteria for heat resistance>
○: No change
×: no gloss, overall dark
[0171]
(2) Heat resistance of diffraction grating formed glass plate
Each of the resin compositions obtained in Examples and Comparative Examples was applied on a slide glass with a spin coater, dried in an oven at 100 ° C. to volatilize the solvent, and the coating amount upon drying was 3 g / m.²The coating film was formed. A nickel stamper for press produced from a diffraction grating (pitch 0.8 μm) formed by electron beam drawing was overlaid on this coating film, heated sufficiently on a hot plate, and then an uneven pattern was embossed with a heating laminator.
[0172]
Subsequently, the integrated exposure amount is 600 mJ / cm with a high-pressure mercury lamp.²A glass plate having a diffraction grating pattern on the surface was produced by irradiating with ultraviolet rays.
[0173]
The obtained diffraction grating pattern-formed glass plate was placed in an oven at 200 ° C. for 1 hour, and its surface was observed and evaluated according to the following criteria. The results are shown in Table 1.
<Evaluation criteria of diffraction grating formed glass plate>
○: No change
×: no gloss, overall dark
[0174]
(3) Abrasion resistance after curing
The resin compositions obtained in Examples and Comparative Examples were each gravure on the easy-adhesive treated surface of a 50 μm thick single-sided easy-adhesive treated polyethylene terephthalate film (Diafoil T600E U-36, manufactured by Diafoil Hequist). Coating with a coater, drying at 100 ° C. to volatilize the solvent, and the coating amount when dried is 2 g / m²A photosensitive film for duplication was formed.
[0175]
Subsequently, the integrated exposure amount is 600 mJ / cm with a high-pressure mercury lamp on the film.²Ultraviolet rays were irradiated so that The obtained cured film was subjected to a Taber abrasion test based on JIS K-7204. The wear wheel was CS-10 and the load was 250 g. The haze difference before starting the test and after 200 rotations was evaluated. The results are shown in Table 1.
[0176]
(4) Dynamic viscoelasticity and glass transition temperature of the resin composition
Each of the resin compositions obtained in Examples and Comparative Examples was coated on a polyester film, dried at room temperature to volatilize the solvent, and the coating amount on drying was 50 g / m.²A cast film was formed. This cast film is cut into strips having a width of 5.0 mm and a length of 12 mm, and the integrated exposure amount is 600 mJ / cm using a high-pressure mercury lamp.²Ultraviolet rays were irradiated so that
[0177]
The dynamic viscoelasticity of the cured cast film was performed using a solid viscoelasticity analyzer RSA-II (manufactured by Rheometric). The measurement conditions were a basic measurement frequency of 1 Hz, a temperature range of 30 to 300 ° C., and a temperature increase rate of 5 ° C./min. The peak of tan δ (dynamic loss elastic modulus / dynamic storage elastic modulus) obtained by measurement was taken as the glass transition temperature. The results are shown in Table 1.
[0178]
[Table 1]

【The invention's effect】
As described above, the photocurable resin according to the present invention has a pendant structure in which one of the isocyanate groups contained in one molecule of the isocyanate compound (b) is suspended from the main chain of the polymer (a). It is a structure in which another isocyanate group contained in the same molecule of the isocyanate compound (b) is urethane-bonded to the hydroxyl group of the polymerizable compound (c), and has a urethane bond with the hydroxyl group contained in the molecule. And a large amount of a photopolymerizable functional group.
[0179]
This photo-curable resin is a film forming property capable of forming a highly viscous or solid thermoformable film at room temperature before curing, a thermoplastic resin capable of accurately replicating a fine uneven pattern with a stamper, a stamper It has shape retention and blocking resistance that is difficult to lose its shape even after it is peeled off. After curing, strength, heat resistance, scratch resistance, water resistance, chemical resistance, surface to be coated (typical) In particular, it has excellent physical properties such as adhesion to a base material) and flexibility such that the base material can bend and stretch.
[0180]
In particular, when using a compound having two or more photopolymerizable functional groups in one molecule as the polymerizable compound (c), there are two or more photopolymerizable functional groups per one hydroxyl group of the polymer (a). Since it is introduced, the crosslinking density becomes very large, and the effect of improving various physical properties after curing is high. Increased crosslink density improves heat resistance and durability (abrasion resistance, chemical resistance, water resistance), and even when exposed to high heat, friction, or solvents, deformation, disappearance, and damage of fine uneven patterns occur. hard.
[0181]
In addition, since the photocurable resin obtained by the method of reacting the adduct (bc) with the polymer (a) is less adversely affected by by-products or unreacted substances, the concavo-convex pattern can be obtained even in the state where these remain mixed. It can be used as a forming material, and is advantageous in that it saves the labor of purification.
[0182]
Since the photocurable resin composition according to the present invention further improves the mold release property by blending a mold release agent as an essential component with respect to the photocurable resin having an excellent mold release property, The stamper pressed against the layer of the curable resin composition can be peeled cleanly without causing the surface of the resin layer to be roughened or the plate is removed, and part of the resin does not remain in the stamper at the time of peeling. It is also excellent in repetitive embossing properties, and is particularly excellent in terms of precision and continuous productivity of fine uneven patterns.
[0183]
When the photocurable resin composition contains inorganic fine particles that can be dispersed in a colloidal form in an organic solvent, the formability, shape maintenance, and releasability are further improved, and the surface has a fine uneven pattern. The structure can be duplicated with high accuracy, and in particular, very complicated fine uneven patterns in recent years can be duplicated accurately. Moreover, since not only the precision of a fine uneven | corrugated pattern rises but blocking resistance also improves, it can wind up and roll, and can be stored and conveyed in an uncured state.
[0184]
Moreover, according to the fine concavo-convex pattern forming method of the present invention, as is apparent from the above description, it is possible to continuously mass-produce fine concavo-convex patterns with high accuracy and excellent physical properties after curing.
[0185]
In addition, since the photocurable resin composition forms a fine concavo-convex pattern forming layer, it is difficult to cause blocking even if it is wound into a roll in an uncured state, so a fine concavo-convex pattern transfer foil can also be formed. It is. When the fine uneven pattern transfer foil is used, productivity can be further improved.
[0186]
According to the present invention, it is needless to say that a fine concavo-convex pattern of a relief hologram or a diffraction grating can be reproduced, and it becomes possible to mass-produce a complicated fine concavo-convex pattern having a more advanced optical function with high accuracy and embossing. Specifically, it forms an optical element that controls at least one of reflection, transmission, scattering, polarization, condensing, or interference of all rays and / or light of a specific wavelength, and a fine uneven pattern such as an information recording element can do.
[0187]
Furthermore, according to the present invention, a fine concavo-convex pattern can be formed with very high accuracy. Therefore, a complementary concavo-convex pattern can be duplicated using a fine concavo-convex pattern to be applied to an optical article as a mold and used as a stamper. Is possible.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of an example of a fine uneven pattern transfer foil.
[Explanation of symbols]
1. Transfer foil
2 ... Support
3 ... release layer
4 ... Fine uneven pattern forming layer
5 ... Reflective layer
6 ... Adhesive layer

Claims (17)

A polymerizable compound (c) having at least two hydroxyl groups, an acrylic resin having a hydroxyl group (a), one hydroxyl group, and one acryloyl group or methacryloyl group is passed through an isocyanate compound (b) having at least two isocyanate groups. It comprises a surface structure formed of a cured product of a photocurable resin composition, which contains a photocurable resin bonded to each other and a release agent as essential components, and has a fine uneven pattern formed thereon. , Optical articles. An adduct (bc) obtained by reacting an isocyanate compound (b) having at least two isocyanate groups, one hydroxyl group, and a polymerizable compound (c) having at least one acryloyl group or methacryloyl group, A fine concavo-convex pattern was formed with a cured product of a photocurable resin composition containing a photocurable resin obtained by reacting with an acrylic resin having a hydroxyl group (a) and a release agent as essential components . An optical article comprising a surface structure. The optical article according to claim 1 or 2, wherein the polymerizable compound (c) has two or more acryloyl groups and / or methacryloyl groups . The optical article according to any one of claims 1 to 3, wherein the release agent is a silicone-based release agent . The optical article according to any one of claims 1 to 4, wherein the fine uneven pattern is a relief hologram or a diffraction grating. The fine uneven pattern reflection of all rays and / or specific wavelengths of light, transmission, scattering, polarization, an optical element for controlling at least one condenser or interference, any one of claims 1 to 5 An optical article according to 1. The optical article according to any one of claims 1 to 6, wherein the fine uneven pattern has a structure for recording information. An isocyanate compound having at least two isocyanate groups, on the support , an acrylic resin (a) having a hydroxyl group, a polymerizable compound (c) having at least one hydroxyl group and one acryloyl group or methacryloyl group. A concavo-convex pattern receptor provided with a fine concavo-convex pattern forming layer made of a photocurable resin composition containing a photocurable resin bonded via (b) and a release agent as essential components is prepared. A method for forming a fine concavo-convex pattern, comprising forming a concavo-convex pattern by pressing a stamper on the surface and then curing the fine concavo-convex pattern forming layer. An adduct (b) obtained by reacting an isocyanate compound (b) having at least two isocyanate groups with a polymerizable compound (c) having at least one hydroxyl group and one acryloyl group or methacryloyl group on a support. A fine concavo-convex pattern forming layer comprising a photocurable resin composition, which contains, as essential components, a photocurable resin obtained by reacting -c) with an acrylic resin having a hydroxyl group (a) and a release agent A method for forming a fine concavo-convex pattern, comprising preparing a provided concavo-convex pattern receptor, pressing a stamper on the surface thereof to form a concavo-convex pattern, and then curing the fine concavo-convex pattern forming layer. The method for forming a fine unevenness pattern according to claim 8 or 9, wherein the polymerizable compound (c) has two or more acryloyl groups and / or methacryloyl groups. The fine uneven | corrugated pattern formation method as described in any one of Claims 8 thru | or 10 in which the said mold release agent is a silicone type mold release agent. The method for forming a fine concavo-convex pattern according to any one of claims 8 to 11 , wherein the fine concavo-convex pattern formation layer is cured after removing the stamper from the fine concavo-convex pattern formation layer . The method for forming a fine concavo-convex pattern according to any one of claims 8 to 12, wherein the fine concavo-convex pattern forming layer cured on the support is transferred onto the second support . On the first support, the polymerizable compound (c) having at least an acrylic resin having a hydroxyl group (a), one hydroxyl group, and one acryloyl group or methacryloyl group has at least two isocyanate groups. A fine concavo-convex pattern forming layer made of a photocurable resin composition containing a photocurable resin bonded via an isocyanate compound (b) and a release agent as essential components is provided to be transferable. A fine concavo-convex pattern transfer foil. Addition by reacting an isocyanate compound (b) having at least two isocyanate groups, a hydroxyl group and a polymerizable compound (c) having at least one acryloyl group or methacryloyl group on the first support. Fine concavo-convex pattern comprising a photocurable resin composition containing, as essential components, a photocurable resin obtained by reacting the product (bc) with an acrylic resin having a hydroxyl group (a) and a release agent A fine concavo-convex pattern transfer foil, wherein the forming layer is provided so as to be transferable.   The fine concavo-convex pattern transfer foil according to claim 14 or 15, wherein the polymerizable compound (c) has two or more acryloyl groups and / or methacryloyl groups. The fine concavo-convex pattern transfer foil according to any one of claims 14 to 16, wherein the release agent is a silicone-based release agent.

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