JP4332373B2 - Volume hologram layer and volume hologram transfer foil - Google Patents

Description

【００５０】
および、
【００５１】
【化２】

【００５２】
で表わされる化合物が挙げられる。
【００５３】
また、本態様においては、上記の中でもカチオン重合性化合物として１分子あたり３官能以上の重合性官能基を有するカチオン重合性化合物を使用することが好ましい。これにより、体積ホログラム層中の架橋密度の高いものとすることができることから、体積ホログラム層の箔切れを良好なものとすることができるからである。これらのカチオン重合性化合物は１種または２種以上組み合わせて用いてもよい。
【００５４】
ここで、本態様においては、上記カチオン重合性化合物を、１重量％〜６０重量％の範囲内、中でも２０重量％〜５０重量％の範囲内用いることが好ましい。
【００５５】
（２）ラジカル重合性化合物
次に、本態様に用いられるラジカル重合性化合物について説明する。本態様に用いられるラジカル重合性化合物は、体積ホログラム層を形成する際に、例えばレーザー照射等によって、後述する光ラジカル重合開始剤系から発生した活性ラジカルの作用により重合する化合物であれば、特に限定されるものではないが、本態様においては、分子中に少なくとも１つのエチレン性不飽和二重結合を有するものが好ましい。
【００５６】
ここで、体積ホログラム層は、例えばレーザー光またはコヒーレンス性の優れた光等によってラジカル重合性化合物を重合させて干渉縞を形成し、像を形成するものである。したがって、ラジカル重合性化合物およびカチオン重合性化合物は、それぞれにおける屈折率が異なるものが選択されて用いられるものであり、どちらの屈折率が大きいものであってもよい。本態様においては、中でも材料選択性の面からラジカル重合性化合物の平均の屈折率が上記カチオン重合性化合物より大きいものであることが好ましく、具体的には、平均の屈折率が０．０２以上大きいことが好ましい。これは、ラジカル重合性化合物と上記カチオン重合性化合物との平均の屈折率の差が上記値より低い場合には、屈折率変調が不十分となり、高精細な像を形成することが困難となるからである。ここでいう平均の屈折率とは、カチオン重合性化合物またはラジカル重合性化合物を重合させた後の重合体について測定する屈折率の平均値をいう。また、本態様の屈折率は、アッベ屈折計により測定された値である。
【００５７】
本態様に用いられるラジカル重合性化合物としては、例えばメチルメタクリレート、ヒドロキシエチルメタクリレート、ラウリルアクリレート、Ｎ−アクリロイルモルホリン、２−エチルヘキシルカルビトールアクリレート、イソボニルアクリレート、メトキシプロピレングリコールアクリレート、１，６−ヘキサンジオールジアクリレート、テトラエチレングリコールジアクリレート、トリメチロールプロパントリアクリレート、ペンタエリスリトールトリアクリレート、ペンタエリスリトールテトラアクリレート、アクリルアミド、メタクリルアミド、スチレン、２−ブロモスチレン、フェニルアクリレート、２−フェノキシエチルアクリレート、２,３−ナフタレンジカルボン酸(アクリロキシエチル)モノエステル、メチルフェノキシエチルアクリレート、ノニルフェノキシエチルアクリレート、β−アクリロキシエチルハイドロゲンフタレート、フェノキシポリエチレングリコールアクリレート、２,４,６−トリブロモフェニルアクリレート、ジフェン酸(２−メタクリロキシエチル)モノエステル、ベンジルアクリレート、２,３−ジブロムプロピルアクリレート、２−ヒドロキシ−３−フェノキシプロピルアクリレート、２−ナフチルアクリレート、Ｎ−ビニルカルバゾール、２−(９−カルバゾリル)エチルアクリレート、トリフェニルメチルチオアクリレート、２−(トリシクロ〔５,２,１０^２・^６〕ジブロモデシルチオ)エチルアクリレート、Ｓ−(１−ナフチルメチル)チオアクリレート、ジシクロペンタニルアクリレート、メチレンビスアクリルアミド、ポリエチレングリコールジアクリレート、トリメチロールプロパントリアクリレート、ペンタエリスリトールトリアクリレート、ジフェン酸(２−アクリロキシエチル)(３−アクリロキシプロピル−２−ヒドロキシ)ジエステル、２,３−ナフタリンジカルボン酸(２−アクリロキシエチル)(３−アクリロキシプロピル−２−ヒドロキシ)ジエステル、４,５−フェナントレンジカルボン酸(２−アクリロキシエチル)(３−アクリロキシプロピル−２−ヒドロキシ)ジエステル、ジブロムネオペンチルグリコールジアクリレート、ジペンタエリスリトールヘキサアクリレート、１,３−ビス〔２−アクリロキシ−３−(２,４,６−トリブロモフェノキシ)プロポキシ〕ベンゼン、ジエチレンジチオグリコールジアクリレート、２,２−ビス(４−アクリロキシエトキシフェニル)プロパン、ビス(４−アクリロキシジエトキシフェニル)メタン、ビス(４−アクリロキシエトキシ−３,５−ジブロモフェニル)メタン、２,２−ビス(４−アクリロキシエトキシフェニル)プロパン、２,２−ビス(４−アクリロキシジエトキシフェニル)プロパン、２,２−ビス(４−アクリロキシエトキシ−３,５−ジブロモフェニル)プロパン、ビス(４−アクリロキシエトキシフェニル)スルホン、ビス(４−アクリロキシジエトキシフェニル)スルホン、ビス(４−アクリロキシプロポキシフェニル)スルホン、ビス(４−アクリロキシエトキシ−３,５−ジブロモフェニル)スルホン、及び上記におけるアクリレートをメタクリレートに変えた化合物、更には特開平２−２４７２０５号公報や特開平２−２６１８０８号公報に記載されているような分子内に少なくともＳ原子を２個以上含む、エチレン性不飽和二重結合含有化合物が挙げられ、これらを１種、または２種以上混合して用いることができる。
【００５８】
ここで本態様においては、このようなラジカル重合性化合物を、１重量％〜６０重量％、中でも２０重量％〜５０重量％用いることができる。
【００５９】
（３）光ラジカル重合開始剤系
次に、本態様に用いられる光ラジカル重合開始剤系について説明する。本態様に用いられる光ラジカル重合開始剤系は、体積ホログラム層を形成する際に、照射される例えばレーザー等によって、活性ラジカルを生成し、上記ラジカル重合性化合物を重合させることが可能な開始剤系であれば、特に限定されるものではなく例えば、米国特許第４,７６６,０５５号、同第４,８６８,０９２号、同第４,９６５,１７１号、特開昭５４−１５１０２４号公報、同５８−１５,５０３号公報、同５８−２９,８０３号公報、同５９−１８９,３４０号公報、同６０−７６７３５号公報、特開平１−２８７１５号公報、特願平３−５５６９号及び「プロシーディングス・オブ・コンフェレンス・オン・ラジエーション・キュアリング・エイジア」 (ＰＲＯＣＥＥＤＩＮＧＳ ＯＦ ＣＯＮＦＥＲＥＮＣＥ ＯＮ ＲＡＤＩＡＴＩＯＮ ＣＵＲＩＮＧ ＡＳＩＡ)」(Ｐ．４６１〜４７７、１９８８年)等に記載されている開始剤系等が挙げられる。
【００６０】
ここで、開始剤系とは、一般に光を吸収する成分である増感剤と活性ラジカル発生化合物や酸発生化合物を組み合わせて用いることができることを意味する。このような光ラジカル重合開始剤系における増感剤は可視レーザー光を吸収するために色素のような有色化合物が用いられる場合が多いが、最終的なホログラムに無色透明性が要求される場合（例えば、自動車等のヘッドアップディスプレーとして使用する場合）の増感剤としては、特開昭５８−２９８０３号公報、特開平１−２８７１０５号公報、特願平３−５５６９号に記載されているようなシアニン系色素の使用が好ましい。シアニン系色素は一般に光によって分解しやすいため、本態様における後露光、または室内光や太陽光の下に数時間から数日放置することでホログラム中の色素が分解されて可視域に吸収を持たなくなり、無色透明な体積ホログラムを得ることができるからである。シアニン系色素の具体例としては、アンヒドロ−３,３´−ジカルボキシメチル−９−エチル−２,２´チアカルボシアニンベタイン、アンヒドロ−３−カルボキシメチル−３´,９−ジエチル−２,２´チアカルボシアニンベタイン、３,３´,９−トリエチル−２,２´−チアカルボキシアニン・ヨウ素塩、３,９−ジエチル−３´−カルボキシメチル−２,２´−チアカルボシアニン・ヨウ素塩、３,３´,９−トリエチル−２,２´−(４,５,４´,５´−ジベンゾ)チアカルボシアニン・ヨウ素塩、２−[３−(３−エチル−２−ベンゾチアゾリデン)−１−プロペニル]−６−[２−(３−エチル−２−ベンゾチアゾリデン)エチリデンイミノ]−３−エチル−１,３,５−チアジアゾリウム・ヨウ素塩、２−[[３−アリル−４−オキソ−５−(３−n−プロピル−５,６−ジメチル−２−ベンゾチアゾリリデン)−エチリデン−２−チアゾリニリデン]メチル]３−エチル−４,５−ジフェニルチアゾリニウム・ヨウ素塩、１,１´,３,３,３´,３´−ヘキサメチル−２,２´−インドトリカルボシアニン・ヨウ素塩、３,３´−ジエチル−２,２´−チアトリカルボシアニン・過塩素酸塩、アンヒドロ−１−エチル−４−メトキシ−３´−カルボキシメチル−５´−クロロ−２,２´−キノチアシアニンベタイン、アンヒドロ−５,５´−ジフェニル−９−エチル−３,３´−ジスルホプロピルオキサカルボシアニンヒドロキシド・トリエチルアミン塩、２−[３−(３−エチル−２−ベンゾチアゾリデン)−１−プロペニル]−６−[２−(３−エチル−２−ベンゾチアゾリデン)エチリデンイミノ]−３−エチル−１,３,５−チアジアゾリウム・ヨウ素塩等が挙げられ、これらの１種、または２種以上を組み合わせて使用することができる。
【００６１】
シアニン系色素と組み合わせて用いてもよい活性ラジカル発生化合物としては、上記の特開昭５８−２９８０３号公報、特開平１−２８７１０５号公報、特願平３−５５６９号に記載されているようなジアリールヨードニウム塩類、あるいは２,４,６−置換−１,３,５−トリアジン類が挙げられる。高い感光性が必要なときは、ジアリールヨードニウム塩類の使用が特に好ましい。上記ジアリールヨードニウム塩類の具体例としては、ジフェニルヨードニウム、４,４´−ジクロロジフェニルヨードニウム、４,４´−ジメトキシジフェニルヨードニウム、４,４´−ジターシャリーブチルジフェニルヨードニウム、３,３´−ジニトロジフェニルヨードニウムなどのクロリド、ブロミド、テトラフルオロボレート、ヘキサフルオロホスフェート、ヘキサフルオロアルセネート、ヘキサフルオロアンチモネート、トリフルオロメタンスルホン酸塩などが例示される。又２,４,６−置換−１,３,５−トリアジン類の具体例としては、２−メチル−４,６−ビス(トリクロロメチル)ー１,３,５−トリアジン、２,４,６−トリス(トリクロロメチル)−１,３,５−トリアジン、２−フェニル−４,６−ビス(トリクロロメチル)−１,３,５−トリアジン、２,４−ビス(トリクロロメチル)−６−(p−メトキシフェニルビニル)−１,３,５−トリアジン、２−(４´−メトキシ−１´−ナフチル)−４,６−ビス(トリクロロメチル)−１,３,５−トリアジン等が挙げられる。
【００６２】
ここで、このような光ラジカル重合開始剤系は、０．３重量％〜１５重量％、中でも１重量％〜１０重量％用いられる。
【００６３】
（４）光カチオン重合開始剤系
次に、本態様で用いられる光カチオン重合開始剤系について説明する。本態様に用いられる光カチオン重合開始剤系は、エネルギー照射によりブレンステッド酸やルイス酸を発生し、上記カチオン重合性化合物を重合させるものであれば、特に限定されるものではないが、特に上記ラジカル重合性化合物を重合させる例えばレーザーやコヒーレンス性の優れた光等に対しては反応せず、その後全面に照射されるエネルギーによって感光するものであることが好ましい。これにより、上記ラジカル重合性化合物が重合する際、カチオン重合性化合物がほとんど反応しないまま存在させることができ、体積ホログラム層における大きな屈折率変調が得られるからである。
【００６４】
ここで、レーザー光やコヒーレンス性の優れた光に対して、低感光性である光カチオン重合開始剤とは、以下の条件で熱分析を行った際、光カチオン重合開始剤系によって開始された光重合に起因するＤＳＣ値の最大値が測定試料１ｍｇあたり５００ｍＷ以下（０ｍＷを含む）であるものとすることができる。
測定条件
測定装置：セイコー電子工業（株）製ＳＳＣ５２００Ｈ熱分析システムにおいて示差走査熱計量ＤＳＣ２２０と光源装置ＵＶ−１を使用
測定試料：対象となる光カチオン重合開始剤系をユニオンカーバイド社製ＵＶＲ−６１１０（カチオン重合性化合物）に対して３重量％溶解させることにより調製（有機溶剤を加えて溶解させた後に有機溶剤を蒸発させてもよい。）
照射光：干渉フィルター（半値幅約１０ｎｍ）を使用してレーザー光またはコヒーレンス性の優れた光と同程度に調節した光を２００ｍＪ／ｃｍ^２照射
このような光カチオン重合開始剤系としては、例えば「ＵＶ硬化；科学と技術（ＵＶ Ｃｕｒｉｎｇ：Ｓｃｉｅｎｃｅ ａｎｄ Ｔｅｃｈｎｏｌｏｇｙ）」、第２３〜７６頁、エス・ピーター・パーパス（Ｓ. Ｐｅｔｅｒ Ｐａｐｐａｓ）編集、ア・テクノロジー・マーケッティング・パブリケーション（Ａ Ｔｅｃｈｎｏｌｏｇｙ Ｍａｒｋｅｔｉｎｇ Ｐｕｂｌｉｃａｔｉｏｎ）および「コメンツ・インオーガニック・ケミストリ（Ｃｏｍｅｎｔｓ Ｉｎｏｒｇ. Ｃｈｅｍ.）」、ビー・クリンゲルト、エム・リーディーカーおよびエイ・ロロフ（Ｂ. Ｋｌｉｎｇｅｒｔ，Ｍ.Ｒｉｅｄｉｋｅｒ ａｎｄ Ａ. Ｒｏｌｏｆｆ）、第７巻、第３号、第１０９〜１３８頁（１９８８年）などに記載されているもの等が挙げられ、これらの１種または２種以上を用いることができる。
【００６５】
また、上記の中でもジアリールヨードニウム塩類で好ましいものとしては上述した光ラジカル重合開始剤系で示したヨードニウムのテトラフルオロボレート、ヘキサフルオロホスフェート、ヘキサフルオロアルセネート、ヘキサフルオロアンチモネート、トリフルオロメタンスルホネート、９,１０−ジメトキシアントラセンスルホネートなどが挙げられる。トリアリールスルホニウム塩類で好ましいものとしては、トリフェニルスルホニウム、４−ターシャリーブチルトリフェニルスルホニウム、トリス(４−メチルフェニル)スルホニウム、トリス(４−メトキシフェニル)スルホニウム、４−チオフェニルトリフェニルスルホニウムなどのスルホニウムのテトラフルオロボレート、ヘキサフルオロホスフェート、ヘキサフルオロアルセネートおよびヘキサフルオロアンチモネート、トリフルオロメタンスルホネート、９,１０−ジメトキシアントラセン−２−スルホネート等が挙げられる。
【００６６】
ここで、このような光カチオン重合開始剤系は、０．３重量％〜１５重量％、中でも１重量％〜１０重量％用いられる。
【００６７】
（５）その他
また、本態様の体積ホログラム層中には、上述した成分以外に、必要に応じて例えば熱重合防止剤、シランカップリング剤、可塑剤、着色剤、高分子結合剤等の添加剤等を含有するものであってもよい
本態様においては、特に高分子結合剤を含有することが好ましく、この高分子結合剤によって、体積ホログラム層を均一にすることができ、また上記ラジカル重合性化合物の重合により形成された像を保つことが可能となるのである。
【００６８】
このような高分子結合剤としては、上記ラジカル重合性化合物および上記カチオン重合性化合物と相溶性の良好なものが用いられ、例えば塩素化ポリエチレン、ポリメチルメタクリレート、メチルメタクリレートと他の（メタ）アクリル酸アルキルエステルとの共重合体、塩化ビニルとアクリロニトリルの共重合体、ポリ酢酸ビニル、ポリビニルアルコール、ポリビニルホルマール、ポリビニルブチラール、ポリビニルピロリドン、エチルセルロース、アセチルセルロース等の側鎖または主鎖にカチオン重合性基を有する高分子等が挙げられ、これらの１種または２種以上を組み合わせて用いることができる。
【００６９】
このような高分子結合剤は、通常２０重量％〜５０重量％、中でも３０重量％〜４０重量％用いられる。
【００７０】
（６）体積ホログラム層
次に、本態様の体積ホログラム層について説明する。本態様の体積ホログラム層は、上記カチオン重合性化合物、上記ラジカル重合性化合物、上記光ラジカル重合開始剤、上記光カチオン重合開始剤、および上記微粒子とを含有する層であれば、特に限定されるものではない。
【００７１】
このような体積ホログラム層の形成は、まず上述した各成分を混合した組成物を、例えば目的とする基材上に、一般的なコーティング手段、例えば、スピンコーター、グラビアコーター、コンマコーター、バーコーター等により塗布し、必要に応じて乾燥する。また例えば２枚のガラス板等の基材の間に上記組成物を注入することによって形成されたものであってもよい。
【００７２】
また、上記材料の塗布の際、必要に応じて溶媒を用いてもよく、この溶媒としては、例えばメチルエチルケトン、アセトン、シクロヘキサノンなどのケトン系溶媒、酢酸エチル、酢酸ブチル、エチレングリコールジアセテートなどのエステル系溶媒、トルエン、キシレンなどの芳香族系溶媒、メチルセロソルブ、エチルセロソルブ、ブチルセロソルブなどのセロソルブ系溶媒、メタノール、エタノール、プロパノールなどのアルコール系溶媒、テトラヒドロフラン、ジオキサンなどのエーテル系溶媒、ジクロロメタン、クロロホルムなどのハロゲン系溶媒等が挙げられる。
【００７３】
次に、上記組成物が塗布された層に、通常ホログラフィー露光装置に用いられるレーザー光はコヒーレンス性の優れた光（たとえば波長３００ｎｍ〜１２００ｎｍの光）による露光によって、上述したラジカル重合性化合物を重合させて、目的とする像の干渉縞を記録する。続いて、未反応のまま残っているカチオン重合性化合物を、上記光カチオン重合開始剤系の感光する光（例えば２００ｎｍ〜７００ｎｍの光）を上記組成物に全面に照射して硬化させることにより、本態様の体積ホログラム層とすることができるのである。この際、未反応のまま残っているラジカル重合性化合物を同時に硬化させてもよい。また、上記像を形成後、エネルギーを全面に照射する前に、赤外線や熱で処理することで、回折効率や回折光のピーク波長、半値幅等を変化させてもよい。
【００７４】
また、体積ホログラム層の用途や種類によって適宜選択されるものであるが、上記組成物の塗布量は、通常１ｇ／ｍ^２〜５０ｇ／ｍ^２の範囲内とされ、体積ホログラム層の膜厚は、通常０．１μｍ〜５０μｍ、中でも１μｍ〜２０μｍの範囲内とされる。
【００７５】
Ｂ．体積ホログラム転写箔
次に、本発明の体積ホログラム転写箔について説明する。本発明の体積ホログラム転写箔は、上述した体積ホログラム層と、基材と、感熱性接着剤層とを有する体積ホログラム転写箔であって、上記基材上に前記ホログラム層が形成され、上記ホログラム層上に感熱性接着剤層が形成されているものである。
【００７６】
本発明の体積ホログラム転写箔は、例えば図１に示すように、基材１と、その基材１上に形成されたホログラム層２と、そのホログラム層２上に形成された感熱性接着剤層３とを有するものである。
【００７７】
本発明の体積ホログラム転写箔は、上記感熱性接着剤と被着体とを接触させて、基材側から熱をかけることにより、感熱性接着剤により体積ホログラム層と被着体とを接着することができ、被着体上に体積ホログラム層を転写することができるのである。この際本発明によれば、上述した箔切れ性の良好な上記体積ホログラム層を有することから、目的とする部分のみ、体積ホログラム層を被着体に転写することが可能となり、様々な用途に用いることが可能な体積ホログラム転写箔とすることができるのである。
【００７８】
このような転写は、例えば図２に示すように、体積ホログラムを転写する被着体６の表面に、上記感熱性接着剤層３が接するように重ね合わせ、上記基材側から体積ホログラムを転写する部分に、例えば加熱可能な金型７等で加熱・加圧して、上記感熱性接着剤層３を溶融接着させ、その後基材１を剥離することによって行うことができる。
【００７９】
以下、本発明の体積ホログラム転写箔の各構成について説明する。なお、体積ホログラム層については、上記体積ホログラム転写箔と同様であるので、ここでの説明は省略する。
【００８０】
１．基材
まず、本発明の体積ホログラム転写箔に用いられる基材について説明する。本発明に用いられる基材は、上記ホログラム層が形成されるものであり、体積ホログラム層を被着体に転写する際には、この基材側から熱転写が行われるものである。したがって、上記ホログラム層が形成可能であり、かつ熱転写の際に加わる熱や圧力に対して耐性を有するものであれば、特に限定されるものではなく、例えばＰＥＴフィルム、ポリ塩化ビニル（ＰＶＣ）フィルム、ポリ塩化ビニリデンフィルム、ポリエチレンフイルム、ポリプロピレンフイルム、ポリカーボネートフイルム、セロハンフィルム、アセテートフィルム、ナイロンフィルム、ポリビニルアルコールフィルム、ポリアミドフィルム、ポリアミドイミドフィルム、エチレン−ビニルアルコール共重合体フィルム、ポリメチルメタクリレート（ＰＭＭＡ）フィルム、ポリエーテルスルホンフィルム、ポリエーテルエーテルケトン（ＰＥＥＫ）フィルム等を用いることができる。また、このような基材の厚さとしては、体積ホログラム転写箔の用途や種類等に応じて適宜選択されるものであるが、通常５μｍ〜２００μｍ、好ましくは１０μｍ〜５０μｍの範囲内とされる。
【００８１】
２．感熱性接着剤層
次に、本発明に用いられる感熱性接着剤層について説明する。本発明に用いられる感熱性接着剤層は、体積ホログラム転写箔の基材と反対側の表面に形成される層であり、体積ホログラム層を熱転写により被着体上に転写する際に密着させて加熱等することにより、体積ホログラム層と被着体とを接着する層である。
【００８２】
このような感熱性接着剤層としては、例えばエチレン−酢酸ビニル共重合樹脂（ＥＶＡ）、ポリアミド樹脂、ポリエステル樹脂、ポリエチレン樹脂、エチレン−イソブチルアクリレート共重合樹脂、ブチラール樹脂、ポリ酢酸ビニルおよびその共重合体樹脂、セルロース系樹脂、ポリメチルメタクリレート樹脂、ポリビニルエーテル系樹脂、ポリウレタン樹脂、ポリカーボネート樹脂、ポリプロピレン樹脂、エポキシ樹脂、フェノール樹脂、スチレンブタジエンスチレンブロック共重合体（ＳＢＳ）、スチレンイソプレンスチレンブロック共重合体（ＳＩＳ）、スチレンエチレンブチレンスチレンブロック共重合体（ＳＥＢＳ）、スチレンエチレンプロピレンスチレンブロック共重合体（ＳＥＰＳ）等の熱可塑性樹脂を用いることができる。上記の中でも、１８０℃以下の温度でヒートシール可能な層であることが好ましく、さらにエチレン−酢酸ビニル共重合樹脂（ＥＶＡ）の酢酸含量２５％以上のものを用いることが好ましい。また、上記樹脂に、必要に応じて感熱性接着剤層が着色されたものであってもよい。
【００８３】
３．体積ホログラム転写箔
次に、本発明の体積ホログラム転写箔について説明する。本発明の体積ホログラム転写箔は、上記体積ホログラム層と、上記基材と、上記感熱性接着剤層とを有するものであって、上記基材上に前記ホログラム層が形成され、上記ホログラム層上に感熱性接着剤層が形成されているものであれば、その構成等は特に限定されるものではなく、上記の層以外に例えば、図３に示すように、基材１と、その基材１上に形成された剥離層４と、その剥離層４上に形成されたホログラム層２と、そのホログラム層２上に形成された感熱性接着剤層３とを有するものであってもよく、またさらに、例えば図４に示すように、基材１と、その基材１上に形成されたホログラム層２と、そのホログラム層２上に形成された反射層５と、その反射層５上に形成された感熱性接着剤層３とを有するものであってもよい。
【００８４】
上記剥離層とは、体積ホログラム転写箔を用いて、被着体上に体積ホログラム層を転写する際に、上記基材と上記体積ホログラム層とを剥離を容易に行うことを可能とする層であり、例えばアクリル系樹脂、塩化ビニル−酢酸ビニル共重合樹脂、ポリエステル樹脂、ポリメタクリル酸エステル樹脂、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、金属酸化物等から、１種または２種以上を混合したもの等を用いることができる。上記の中でも、分子量２００００〜１０００００程度のアクリル系樹脂単独、またはアクリル系樹脂と分子量８０００〜２００００の塩化ビニル−酢酸ビニル共重合樹脂とからなり、さらに添加剤として分子量１０００〜５０００のポリエステル樹脂が１〜５重量％含有する組成物からなることが特に好ましい
また、本発明においては特に、上記基材と上記体積ホログラム層との間の剥離力が１〜５ｇ／インチ（９０°剥離）となるようなものであることが好ましい。また、その厚みは剥離力、箔切れ等の面から、０．１μｍ〜２μｍの範囲内であることが好ましい。
【００８５】
また、反射層としては、上記感熱性接着剤層と体積ホログラム層との間に形成されるものであり、この反射層に光を反射する例えば金属薄膜等を用いると、不透明タイプの体積ホログラムとなり、ホログラム層と屈折率差がある透明な物質を用いた場合には、透明タイプの体積ホログラムとなるがいずれも本発明に用いることが可能である。このような反射層は、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により形成することが可能である。
【００８６】
また、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等の金属およびその酸化物、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が挙げられる。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、中でも２０〜２００ｎｍの範囲であることが好ましい。
【００８７】
一方、透明タイプのホログラムを形成する薄膜としては、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、ホログラム形成層（光硬化樹脂層）の樹脂と屈折率の異なる透明材料が挙げられる。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、より好ましくは０．５以上であり、１．０以上が最適である。また、上記以外では２０ｎｍ以下の金属性反射膜が挙げられ、好適に使用される透明タイプ反射層としては、酸価チタン（ＴｉＯ_２ ）、硫化亜鉛（ＺｎＳ）、Ｃｕ・Ａｌ複合金属酸化物等が挙げられる。
【００８８】
さらに、本発明においては、上記剥離層と体積ホログラム層との間、体積ホログラム層と感熱性接着剤層との間のいずれかもしくは双方にバリア層を設けることもできる。本発明の製造手段に使用する感光材料や剥離層ならびに感熱性接着剤層の組み合わせによっては、経時的に体積ホログラム層から他の層への低分子量成分の移行が起こり、これに起因して記録されたホログラムのピーク波長が青側（短波長側）に移行したり、剥離層等にこれが移行した場合にはその剥離性を変化させたりする場合がある。上記のようなバリア層を設けることによって、これらの阻害要因を解消することができるのである。
【００８９】
このようなバリア層として用いる材料としては、そのバリア性を発現する材料であれば、特に制限はないが、通常、透明性有機樹脂材料を用いることによってその目的を達成することができる。中でも、無溶剤系の３官能以上、好ましくは６官能以上の、紫外線や電子線等の電離放射線に反応する電離放射線硬化性エポキシ変性アクリレート樹脂、ウレタン変性アクリレート樹脂、アクリル変性ポリエステル樹脂等を用いることができる。特に、その中でもウレタン変性アクリレート樹脂がそのバリア性の高さから好ましく用いられる。
【００９０】
また、これらの電離放射線硬化性樹脂としては、そのコーティング適正、最終的に得られるバリア層の硬度等を考慮すると、その分子量は５００〜２０００の範囲のものが好ましく用いられる。また、バリア層のコーティングは基本的に無溶剤系であるため、体積ホログラム層、剥離層、感熱性接着剤層のどの層にも積層形成することができる。
【００９１】
また、各層の密着性が弱い場合には、密着向上層等が形成されたものであってもよい。
【００９２】
上述したような本発明の体積ホログラム転写箔は、上記基材、体積ホログラム層、および感熱性接着剤層を、それぞれ順次積層して製造されるものであってもよいが、各部材をそれぞれ独立の工程によって準備し、これらを積層することによって製造されるものであってもよい。
【００９３】
例えば、像を記録した体積ホログラム層、剥離層を形成した基材、および感熱性接着剤層を準備し、これらを積層する方法等が挙げられる。各部材をそれぞれ独立の工程によって準備する場合には、例えば基材上に剥離層等をドライプロセス等により形成することが可能となり、様々な材料を用いることや、製造効率等の面から好ましいものとすることができる。
【００９４】
また例えば、上記基材（剥離層が形成されていてもよい）上に体積ホログラム層を形成した後、体積ホログラム層に像を記録した部材と、感熱性接着剤層とを準備し、これらを積層するもの等であってもよい。この場合、上述した体積ホログラム層を形成する組成物を支持体上に塗布し、例えばレーザー等を照射することにより、ラジカル重合性化合物を重合させて像を記録し、上記基材と積層する。その後、上記組成物全面に照射することにより、像が記録された体積ホログラム層と上記基材とが積層された部材を形成する。続いて、上記支持体を剥離して、感熱性接着剤を例えば１００℃〜１８０℃に加熱しながら積層する方法等とすることができる。
【００９５】
ここで、上述した本発明の体積ホログラム積層体は、例えばプラスチックカード、携帯電話、金券、日用品またはＣＤ−ＲＯＭのパッケージなどに適用可能である。
【００９６】
また、本発明においては、上記基材と上記体積ホログラム層との層間接着力を制御する方法も包含する。
【００９７】
すなわち、上記の体積ホログラム転写箔の層構成において剥離層を有する場合には、剥離層と支持フィルムとの間の層間接着力Ａと剥離層とホログラム形成層との間の層間接着力Ｂと、体積ホログラム層と感熱性接着剤層との間の層間接着力Ｃの相対関係ならびにＢの値が、下記の関係を満足することが望ましい。
層間接着力： Ｃ≧Ｂ＞Ａ
Ｂ値： ６００ｇｆ／インチ
なお、本発明は、上記実施形態に限定されるものではない。上記実施形態は、例示であり、本発明の特許請求の範囲に記載された技術的思想と実質的に同一な構成を有し、同様な作用効果を奏するものは、いかなるものであっても本発明の技術的範囲に包含される。
【００９８】
【実施例】
以下、実施例および比較例を挙げて本発明を具体的に説明する。実施例中の「部」および「％」は特に断りのない限り全て重量基準である。
【００９９】
〔破断点伸度、破断強度測定方法〕
本発明における体積ホログラム層の破断点伸度、破断強度は、ＪＩＳ Ｋ７１２７−１９８９に従うＩＮＳＴＲＯＮ社製試験機「ＩＮＳＴＲＯＮ５５６５」により下記の条件により測定した値から、応力（Ｓｔｒｅｓｓ）−伸度（Ｓｔｒａｉｎ）曲線（Ｓ−Ｓ曲線）を自記録させ、この曲線から破断点伸度を求めた値である。
【０１００】
測定雰囲気：２５℃または１３０℃
試験片 ：２５ｍｍ幅
引張り速度：２ｍｍ／分
〔破断強度および破断点伸度測定用サンプルの作製〕
体積ホログラム記録用感光性組成物は、
カチオン重合性化合物（表中「ＣＭ」と記載） ３０重量部
ラジカル重合性化合物（表中「ＲＭ」と記載） ３０重量部
増感剤（表中「ＤＹＥ」と記載） １重量部
活性ラジカル発生化合物（表中「ＰＩ」と記載） ４重量部
高分子結合剤（表中「ＢＰ」と記載 ３０重量部
微粒子 ５重量部
で調製した。この調製において、ラジカル重合性化合物として、ビス（４−アクリロキシジエトキシフェニル）メタンを、光ラジカル重合開始剤系として３，９−ジエチル−３´−カルボキシメチル−２，２´−チアカルボシアニン・ヨウ素塩とジフェニルヨードニウムヘキサフルオロアンチモネートとの組み合わせを用いた。光カチオン重合開始剤系はジフェニルヨードニウムヘキサフルオロアンチモネートを兼用させた。高分子結合剤として、メチルメタクリレート／グリシジルメタクリレートの共重合体（共重合比９０／１０、Ｍｗ５００００）を用いた。
【０１０１】
上記の体積ホログラム記録用感光性組成物４０重量部に、メチルエチルケトン（ＭＥＫ）３０重量部およびメタノール３０重量部を加え、体積ホログラム記録用感光性組成物の溶液を得た。この組成物の溶液を５０μｍのＰＥＴフィルム（デュポン社製Ｍｙｌｅｒ２００）に乾燥後の膜厚が２０μｍとなるようにグラビアコートで塗工し、さらに塗工面に５０μｍのＰＥＴフィルムをラミネートして、体積ホログラム形成層を有する第１部材を作製した。
【０１０２】
このフィルムを高圧水銀灯４Ｊ／ｃｍ^２で硬化させた後、支持体から剥がし、幅２０ｍｍ、長さ５０ｍｍのフィルム状試験片を作製した。なお、フィルム形成の際に、支持体表面が離型処理されていると、硬化ホログラム層の剥離が容易となる。
【０１０３】
〔箔切れ性評価用サンプルの作製〕
体積ホログラム形成層を有する第１部材（ＰＥＴフィルム／体積ホログラム形成層／（剥離性）ＰＥＴフィルム）、剥離層を有する第２部材（剥離層／ＰＥＴフィルム）、および感熱性接着剤層を有する第３部材（感熱性接着剤層／剥離性ＰＥＴフィルム）をそれぞれ独立の工程によって別々に用意した。
【０１０４】
〔第１部材の作製〕
上記〔破断強度および破断点伸度測定用サンプルの作製〕で調製した体積ホログラム記録用感光性組成物４０重量部に対し、メチルエチルケトン（ＭＥＫ）３０重量部およびメタノール３０重量部を加え、体積ホログラム記録用感光性組成物の溶液を得た。この組成物の溶液を５０μｍのＰＥＴフィルム（ルミラーＴ６０（５０μｍ）；東レ（株）製）に乾燥後の膜厚が１０μｍとなるようにグラビアコートで塗工し、さらに塗工面に表面離型処理ＰＥＴフィルム（トーセロ（株）製・ＳＰ−ＰＥＴ（３８μｍ））をラミネートして、体積ホログラム形成層を有する第１部材を作製した。
【０１０５】
〔第２部材の作製〕
第２部材はＰＥＴフィルム（ルミラーＴ６０（５０μｍ）；東レ（株）製）上に剥離層（ハクリニス４５−３）を公知の塗工方法を利用して乾燥後の膜厚が１μｍとなるように均一にコートした。
【０１０６】
〔第３部材の作製〕
第３部材は、表面離型処理ＰＥＴフィルム（ＳＰ−ＰＥＴ（５０μｍ）；トーセロ（株）製）上に感熱性接着剤（ＥＣ１２００；中央理化（株）製）を、公知の塗工方法を利用して乾燥後の層厚が２μｍとなるように塗布して作製した。
【０１０７】
〔評価サンプルの作製〕
上記の体積ホログラム形成層を有する第１部材の一方のＰＥＴフィルムを剥離し、予め用意された体積ホログラム原版に、第１部材をラミネートした。次いで波長５１４ｎｍのアルゴンレーザー光を照度１ｍＷ／ｃｍ^２で６０秒間露光し、干渉縞を形成した。続いて１００℃で１０分間加熱処理し、第１部材の片面の表面離型処理ＰＥＴフィルムを剥がし、体積ホログラム形成層の面に対向するように第２部材の剥離層面を８０℃にてラミネートした。これによりＰＥＴフィルム／剥離層／体積ホログラム形成層／ＰＥＴフィルムからなる積層体を得た。その後、体積ホログラム形成層を高圧水銀灯にて２５００ｍＪ／ｃｍ^２の照射による定着処理（後露光）を行い、感材に接するＰＥＴフィルムを剥がし、剥がした面に第３部材の感熱性接着剤層面を１００℃にてラミネートした。これによりＰＥＴフィルム／剥離層／体積ホログラム層／感熱性接着剤層／表面離型処理ＰＥＴフィルムからなる積層体から表面離型処理ＰＥＴフィルムを剥がし、本発明の体積ホログラム転写箔を得た。
【０１０８】
これにより、以下に示す実施例、比較例の全てにおいて十分実用範囲にある無色透明の体積ホログラム転写箔が得られた。
【０１０９】
〔体積ホログラム転写箔の転写試験方法〕
ＰＥＴフィルム／剥離層／体積ホログラム層／感熱性接着剤層からなる体積ホログラム転写箔を作製した。体積ホログラムを転写させる被着体（塩化ビニルカード）の表面に、本発明の体積ホログラムの転写箔を、該転写箔の感熱性接着剤層が接するように重ね合わせ、体積ホログラムを転写させる部分の転写箔の上から、１０ｍｍ×１０ｍｍの矩形金型を１５０℃で押し当てた。所望部分の感熱性接着剤層を溶融接着させて、転写層を付与した。
【０１１０】
箔切れ性の評価は、転写部外縁に余分な転写箔が付着しているかを確認することにより行った。評価基準として、転写部分と非転写部分とが、明瞭に破断した場合を○、特に再現良く明瞭に破断した場合を◎とした。また、転写部の４辺のうち、１辺もしくは２辺にわずかに非転写部が付着している場合を△、２以上の辺に大きな非転写部が付着している場合を×とした。ここでいう「非転写部」とは、体積ホログラム転写箔から体積ホログラムを付着させる際に、付着が望まれない部分をいう。
【０１１１】
（実施例１〜１６、比較例１〜８）
カチオン重合性化合物の種類、フッ素系粒子（ＦＭ１０８重合体）の粒径の組み合わせを変えて、体積ホログラム層の破断強度、破断点伸度、転写適性を評価した。これらの各条件と結果を下記の表１に示す。いずれの実施例においても、十分実用範囲にある体積ホログラム転写箔が得られた。
【０１１２】
【表１】

【０１１３】
（実施例１７〜４０、比較例９〜１６）
次に、カチオン重合性化合物の種類、フッ素系粒子（ＰＴＦＥ重合体）の粒径の組み合わせを変えて、体積ホログラム層の破断強度、破断点伸度、転写適性を評価した。これらの各条件と結果を下記の表２に示す。いずれの実施例においても、十分実用範囲にある体積ホログラム転写箔が得られた。
【０１１４】
【表２】

【０１１５】
（比較例１７〜２４）
次に、粒子を含有させず、カチオン重合性化合物の種類を変えて、体積ホログラム層の破断強度、破断点伸度、転写適性を評価した。これらの各条件と結果を下記の表３に示す。いずれの比較例においても、実用範囲にある体積ホログラム転写箔が得られなかった。
【０１１６】
【表３】

【０１１７】
（比較例２５、２６）
次に、体積ホログラム記録材料にオムニデックス３５２を使用し、特願平１０−９７１７３号公報の実施例１に記載の配合でフッ素系粒子（ＦＭ１０８重合体：２００ｎｍ、ＰＴＦＥ粒子：２００ｎｍ）を添加し、体積ホログラム層の破断強度、破断点伸度、転写適性を評価した。これらの各条件と結果を下記の表４に示す。いずれの比較例においても、実用範囲にある体積ホログラム転写箔が得られなかった。
【０１１８】
【表４】

【０１１９】
（比較例２７、比較例２８）
次に、体積ホログラム記録材料にオムニデックス３５２を使用し、特願平１０−９７１７３号公報の実施例１および２に記載の配合で各粒子を含んだ体積ホログラム層の破断強度、破断点伸度、転写適性を評価した。これらの各条件と結果を下記の表５に示す。いずれの比較例においても、実用範囲にある体積ホログラム転写箔が得られなかった。
【０１２０】
【表５】

【０１２１】
（比較例２９〜３６）
次に、粒子をコロイダルシリカ（ＭＩＢＫ−ＳＴ（日産化学社製））とし、カチオン重合性化合物の種類を変えて、体積ホログラム層の破断強度、破断点伸度、転写適性を評価した。これらの各条件と結果を下記の表６に示す。いずれの比較例においても、実用範囲にある体積ホログラム転写箔が得られなかった。
【０１２２】
【表６】

【０１２３】
（実施例４１、４２）
次に、粒子をチタニア微粒子（Ｒ−６３０（石原産業社製））とし、カチオン重合性化合物の種類を変えて、体積ホログラム層の破断強度、破断点伸度、転写適性を評価した。これらの各条件と結果を表７に示す。いずれの実施例においても、十分実用範囲にある体積ホログラム転写箔が得られた。
【０１２４】
【表７】

【０１２５】
表１から表７までで使用したカチオン重合性化合物「ＣＭ」を下記の表８に示す。
【０１２６】
【表８】

【０１２７】
また、上記で使用したラジカル重合性化合物の屈折率は、１．５４であり、上記カチオン重合性化合物の屈折率より大きいものである。なお、屈折率はアッベ屈折計を用いてＪＩＳ Ｋ４１７２に準拠して測定した値である。
【０１２８】
さらに、表１から表７までで使用した微粒子を下記の表９に示す。
【０１２９】
【表９】

【０１３０】
【発明の効果】
本発明によれば、２５℃および１３０℃における破断強度と破断点伸度が、上記範囲内であることによって、例えば体積ホログラム層を体積ホログラム転写箔とした場合、熱転写の際に、箔切れを良好なものとすることができ、様々な用途に用いることが可能な体積ホログラム層とすることができるのである。
【図面の簡単な説明】
【図１】本発明の体積ホログラム転写箔の一例を示す概略断面図である。
【図２】本発明の体積ホログラム転写箔の転写の一例を示す概略断面図である。
【図３】本発明の体積ホログラム転写箔の他の例を示す概略断面図である。
【図４】本発明の体積ホログラム転写箔の他の例を示す概略断面図である。
【符号の説明】
１ … 基材
２ … 体積ホログラム層
３ … 感熱性接着層
４ … 剥離層
５ … 反射層
６ … 被着体
７ … 金型[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a volume hologram layer used for, for example, a volume hologram transfer foil, and a volume hologram transfer foil using the volume hologram layer.
[0002]
[Prior art]
The hologram is obtained by recording two light beams (object light and reference light) having the same wavelength on the photosensitive material as interference fringes. When this hologram is irradiated with light under the same conditions as the original object light, a diffraction phenomenon due to interference light occurs, and the same wavefront as the original object light can be reproduced. Holograms are classified into several types (surface relief holograms, volume holograms, etc.) depending on the form of interference fringes generated by the interference of laser light or light with excellent coherence.
[0003]
Here, the hologram is often used for security purposes by utilizing the characteristic that it is difficult to duplicate the same design. In this application, a surface relief type hologram in which interference fringes are recorded by forming fine irregularities on the surface of the hologram forming layer is generally used. However, in recent years, with the spread of hologram technology and the advancement of counterfeit technology, imitation replication of surface relief holograms has become possible, making it difficult to apply to security applications.
[0004]
On the other hand, a volume hologram is produced by three-dimensionally recording interference fringes generated by light interference as fringes having different refractive indexes in the thickness direction of the photosensitive material. This volume hologram is easy to judge whether it is true or not because the manufacturing method is different from the surface relief hologram that is widely used at present and the visual effect is completely different. In addition, since manufacturing equipment is expensive and imitation of a design requires advanced design technology, it is extremely difficult to produce a hologram for the purpose of counterfeiting. For this reason, use of volume holograms for security purposes is demanded.
[0005]
Here, in order to attach the hologram to the adherend, a transfer foil including a base film, a hologram layer and a heat-sensitive adhesive layer is usually used. In this case, the heat-sensitive adhesive layer in the hologram transfer foil and the adherend are brought into contact, and thermal transfer is performed from the base film side. At this time, in order to form the hologram layer in a desired shape, it is necessary that the hologram layer is cut, that is, has a good foil cutting property, and the hologram is surely applied to the adherend. However, the volume hologram needs to have a thick volume hologram layer in order to obtain a clear image due to the characteristic of recording interference fringes in the formation layer, and as a result, the foil breakability is inferior. In addition, in order to mass-produce volume hologram transfer foil, it is necessary to use a photopolymer that can be processed by a dry process. However, since a non-reactive plasticizer or the like is usually used for improving the refractive index modulation ability, the produced volume hologram is softened, and accordingly the foil breakability is further deteriorated.
[0006]
As such a volume hologram, for example, a volume hologram recording photosensitive composition excellent in coating strength (see Patent Document 1) and a volume hologram laminate forming label to which fine particles are added have been proposed (Patent Document). 2). A hologram transfer foil that defines the elongation at break is also proposed (see Patent Document 3). However, none of the methods has led to a hologram layer that has a clear image, is excellent in transferability, and can be mass-produced.
[0007]
[Patent Document 1]
Japanese Patent No. 2873126
[Patent Document 2]
JP-A-10-97173
[Patent Document 3]
JP 2000-272295 A
[0008]
[Problems to be solved by the invention]
In view of the above, it is desired to provide a volume hologram layer having good foil cutting properties, for example, used for volume hologram transfer foils.
[0009]
[Means for Solving the Problems]
In the present invention, at a layer thickness of 20 μm, the breaking strength at 25 ° C. is in the range of 10 MPa to 30 MPa, the elongation at break is in the range of 0.1% to 3%, and the breaking strength at 130 ° C. is 0.1 MPa. Provided is a volume hologram layer characterized in that the elongation at break is in the range of 0.1% to 5% in the range of ˜1 MPa.
[0010]
According to the present invention, when the breaking strength and elongation at break at 25 ° C. and 130 ° C. are within the above ranges, for example, when the volume hologram layer is a volume hologram transfer foil, the foil breakage may be caused during thermal transfer. It can be a good volume hologram layer that can be used for various purposes.
[0011]
In the said invention, it is preferable to contain microparticles | fine-particles. This is because by incorporating fine particles into the volume hologram layer, the foil cutting property can be improved.
[0012]
The present invention also includes a cationic polymerizable compound, a radical polymerizable compound, a photo radical polymerization initiator system for polymerizing the radical polymerizable compound, a photo cationic polymerization initiator system for polymerizing the cationic polymerizable compound, an average A volume hologram layer comprising fine particles having a particle diameter of 100 nm to 600 nm is provided.
[0013]
According to the present invention, an image can be formed as a volume hologram layer by containing the cationic polymerizable compound and the radical polymerizable compound and their polymerization initiator system, and the fine particles. Therefore, for example, when the volume hologram layer is a volume hologram transfer foil, the foil breakage can be improved during thermal transfer.
[0014]
In the said invention, it is preferable that the said cationically polymerizable compound is a liquid at normal temperature. Accordingly, when forming a volume hologram on which an image is formed, for example, by irradiating a laser beam or the like, movement of the cationic polymerizable compound in the layer is facilitated, and an image of the volume hologram is efficiently formed. This is because it becomes possible.
[0015]
Moreover, in the said invention, it is preferable that the said cationically polymerizable compound is a compound which has a polymeric functional group more than trifunctional per molecule. This is because the cross-linking density in the volume hologram layer can be made high, and the volume hologram layer can have a good foil breakage.
[0016]
Furthermore, in the above invention, the volume hologram layer has a layer thickness of 20 μm, a breaking strength at 25 ° C. in the range of 10 MPa to 30 MPa, an elongation at break in the range of 0.1% to 3%, and It is preferable that the breaking strength at 130 ° C. is in the range of 0.1 MPa to 1 MPa, and the elongation at break is in the range of 0.1% to 5%. When the breaking strength and breaking elongation at 25 ° C. and 130 ° C. are within the above ranges, for example, when the volume hologram layer is a volume hologram transfer foil, the foil breakage should be good during thermal transfer. Because you can.
[0017]
In the present invention, the fine particles are preferably contained in an amount of 1 to 30% by weight. If the content of the fine particles is less than the above range, it is difficult to make the foil breakage good. If the content is more than the above range, the volume hologram layer has a high strength. It is because it may become weak.
[0018]
In the present invention, the fine particles can be fluorine-based fine particles. This is because good foil breakage can be expressed by using the above-mentioned fine particles as fluorine-based fine particles.
[0019]
In the present invention, the fine particles can be titania fine particles. This is because even when the fine particles are titania fine particles, good foil breakage can be expressed.
[0020]
The present invention is also a volume hologram transfer foil having the volume hologram layer of the invention, a base material, and a heat-sensitive adhesive layer, wherein the volume hologram layer is formed on the base material, and the volume hologram There is provided a volume hologram transfer foil, wherein a heat-sensitive adhesive layer is formed on the layer.
[0021]
According to this invention, since it has the said volume hologram layer, it can be set as the volume hologram transfer foil with favorable foil cutting | disconnection, and can be used for various uses.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a volume hologram layer and a volume hologram transfer foil using the volume hologram layer. Each will be described below.
[0023]
A. Volume hologram layer
First, the volume hologram layer of the present invention will be described. There are two embodiments of the volume hologram layer of the present invention. As a first aspect, at a layer thickness of 20 μm, the breaking strength at 25 ° C. is in the range of 10 MPa to 30 MPa, the elongation at break is in the range of 0.1% to 3%, and the breaking strength at 130 ° C. Within the range of 0.1 MPa to 1 MPa, the elongation at break is within the range of 0.1% to 5%. As a second aspect, the cationic polymerizable compound, the radical polymerizable compound, and the above It contains a radical photopolymerization initiator system for polymerizing a radically polymerizable compound, a cationic photopolymerization initiator system for polymerizing the cationically polymerizable compound, and fine particles having an average particle diameter of 100 nm to 600 nm.
[0024]
According to the present invention, in any aspect, when the volume hologram layer is used for, for example, a volume hologram transfer foil, the foil breakage is good when the volume hologram layer is formed on the adherend by thermal transfer. It can be done.
[0025]
Each aspect will be described below.
[0026]
1. First aspect
First, the 1st aspect of the volume hologram layer of this invention is demonstrated. In the first aspect of the volume hologram layer of the present invention, the volume hologram layer having a layer thickness of 20 μm has a breaking strength at 25 ° C., a breaking strength at 130 ° C. and an elongation at break within a predetermined range. .
[0027]
Thereby, when the volume hologram layer is used for, for example, a volume hologram transfer foil, the foil can be cut off.
[0028]
Specifically, the breaking strength and the breaking elongation at 25 ° C. are preferably in the range of 10 MPa to 30 MPa, more preferably 15 MPa to 30 MPa, and the breaking elongation is 0.1% to 3%. Within the range, it is preferable that it is in the range of 0.1% to 1%. Further, the breaking strength at 130 ° C. is preferably in the range of 0.1 MPa to 1 MPa, particularly 15 MPa to 30 MPa, and the elongation at break is in the range of 0.1% to 5%, especially 0.1% to 1 It is preferably within the range of 5%.
[0029]
Here, the breaking strength and elongation at break are values measured at a pulling speed of 2 mm / min using a self-recording tester (Tensilon universal tester INSTRON5565 manufactured by INSTRON).
[0030]
Furthermore, the volume hologram layer of this embodiment preferably has a glass transition temperature of 100 ° C. or higher. Thereby, even when heat is applied to the volume hologram layer of this embodiment, the volume hologram layer can be stable, and the volume hologram layer can be transferred by, for example, a thermal transfer method or the like.
[0031]
Here, the volume hologram layer in this embodiment preferably contains fine particles. Thereby, a defect can be intentionally formed in the volume hologram layer, and brittleness can be imparted to the volume hologram layer. Due to this brittleness, the breaking strength and elongation at break can be within the above ranges.
[0032]
In this embodiment, the fine particles preferably have an average particle size in the range of 100 nm to 600 nm, more preferably in the range of 150 nm to 500 nm, and particularly in the range of 200 nm to 500 nm. When the average particle size of the fine particles is smaller than the above range, it is difficult to impart brittleness to the volume hologram layer, and when the average particle size of the fine particles is larger than the above range, the volume hologram of the volume hologram layer This is because it may adversely affect image formation. In this embodiment, it is particularly preferable that the particle diameter is smaller than the wavelength of laser light or the like used when recording an image on the volume hologram layer.
[0033]
Here, the average particle diameter is generally used to indicate the particle size of the particles, and in this embodiment, is a value measured by a laser method. The laser method is a method of measuring an average particle size, a particle size distribution, and the like by dispersing particles in a solvent and thinning and calculating scattered light obtained by applying a laser beam to the dispersion solvent. Here, the average particle size is a value measured using a particle size analyzer Microtrac UPA Model-9230 manufactured by Leeds & Northrup as a particle size measuring device by a laser method.
[0034]
The fine particles are preferably contained in the volume hologram layer in the range of 1% by weight to 30% by weight, particularly in the range of 5% by weight to 20% by weight. This is because when the amount of the fine particles is less than the above range, it becomes difficult to contribute to the foil breakage of the volume hologram layer. When the amount is more than the above range, the strength and transparency of the volume hologram layer are maintained. This is because it becomes difficult.
[0035]
Here, the fine particles are not particularly limited as long as they have the above-mentioned particle diameter. For example, as the resin skeleton, low-density polyethylene, high-density polyethylene, polypropylene, (meth) acryl, polyvinyl chloride, Organic fine particles including polyamide, polyimide, polycarbonate, epoxy or urethane, and copolymers thereof, silica, mica, talc, clay, graphite, calcium carbonate, alumina, aluminum hydroxide, ferrite, china clay, kaolin, titanium dioxide, glass Inorganic particles such as flakes, asbestos, wax stone powder, silica stone powder, barium sulfate, Shelben, chamotte, and titania can be used, and these fine particles may be used alone or in combination of two or more.
[0036]
Among these, in this embodiment, fluorine fine particles or titania fine particles which are fine particles of a fluorine-containing resin in which part or all of hydrogen in the skeleton or side chain in the resin of the organic fine particles is substituted with fluorine atoms are used. Is preferred. This is because it is possible to improve the foil cut of the volume hologram layer.
[0037]
In addition, the fluorine-based fine particles, which are the fine particles of the fluorine-containing resin, have a small friction coefficient, and thus have little interaction with other components contained in the volume hologram layer, and impart a brittleness to the volume hologram layer in a small amount. It becomes possible to do. As the fluorine-based fine particles, those obtained by partially or fully fluorinating the organic fine particles exemplified above, or those obtained by treating the surface of the fine particles with a fluorine-containing compound can be used. In particular, it is preferable to use fluorine-based fine particles utilizing a (meth) acrylic acid ester compound. Specific examples of such fine particles include a fluorine-containing acrylic ester described in JP-A-5-194322, a fluorine-containing (meth) acrylic compound described in JP-A-9-104655, and JP-A-2001-72646. A monomer polymer using at least one fluorine monomer represented by the fluorine-containing polyfunctional (meth) acrylic acid ester compound described above, or having at least one ethylenically unsaturated bond in one molecule not containing other fluorine Monomer copolymer copolymerized with compound, fluorine-containing resin composite fine particles disclosed in JP-A-6-73137, fluorine-containing (meth) acrylic acid ester copolymer disclosed in JP-A-5-194668, etc. Is mentioned. These fluorine-based fine particles can be used alone or in combination.
[0038]
Further, as the titania fine particles used in the present embodiment, for example, rutile type titania fine particles of titanium dioxide that do not deteriorate with time in the hologram layer due to the photocatalytic action are used. Further, as a method for improving the foil breakage, a surface treatment with a silane coupling agent containing a fluorinated alkyl or a surface treatment with a metal oxide such as alumina or silica is effective. Specifically, R-820, R-830, R-930, R-550, R-630, R-680, CR-80, CR-90, CR-95, CR-60, etc. manufactured by Ishihara Sangyo are listed. It is done.
[0039]
Here, as a material used for the volume hologram layer of this aspect, a material used for a normal volume hologram layer can be used, and for example, the same material as the second aspect described later can be used. Since there is, explanation here is omitted.
[0040]
2. Second aspect
Next, a second aspect of the volume hologram layer of the present invention will be described. The second aspect of the volume hologram layer of the present invention includes a cationic polymerizable compound, a radical polymerizable compound, a photo radical polymerization initiator system for polymerizing the radical polymerizable compound, and a light for polymerizing the cationic polymerizable compound. It contains a cationic polymerization initiator system and fine particles having an average particle diameter of 100 nm to 600 nm.
[0041]
According to this aspect, it is possible to form an image as a volume hologram layer by containing the cationically polymerizable compound and the radically polymerizable compound and a polymerization initiator system thereof. By containing fine particles having an average particle diameter within the range, when the volume hologram layer is used for a volume hologram transfer foil or the like, the foil breakage can be improved.
[0042]
Specifically, the breaking strength and the breaking elongation at 25 ° C. are preferably in the range of 10 MPa to 30 MPa, more preferably 15 MPa to 30 MPa, and the breaking elongation is 0.1% to 3%. It is preferable that it is in the range, especially in the range of 0.1% to 1%. Further, the breaking strength at 130 ° C. is preferably in the range of 0.1 MPa to 1 MPa, particularly 15 MPa to 30 MPa, and the elongation at break is in the range of 0.1% to 5%, especially 0.1% to 1 It is preferably within the range of 5%. Here, the breaking strength and the elongation at break are values measured by the method described above.
[0043]
Further, the volume hologram layer of this embodiment preferably has a glass transition temperature of 100 ° C. or higher. Thereby, even when heat is applied to the volume hologram layer of this embodiment, the volume hologram layer can be stable, and the volume hologram layer can be transferred by, for example, a thermal transfer method or the like.
[0044]
Hereafter, each structure of the volume hologram layer of this aspect is demonstrated, respectively. Note that the fine particles used in this embodiment are the same as those in the first embodiment described above, and thus the description thereof is omitted here.
[0045]
(1) Cationic polymerizable compound
First, the cationically polymerizable compound used in this embodiment will be described. The cationically polymerizable compound used in this embodiment is a compound that undergoes cation polymerization with Bronsted acid or Lewis acid generated by decomposition of a photocationic polymerization initiator system described later upon receiving energy irradiation.
[0046]
Here, the volume hologram layer is formed by, for example, irradiating the target image with a laser to polymerize a radically polymerizable compound described later, and then irradiating the entire surface with energy to form a cationic polymerizable compound or the like. By polymerizing the uncured material. In addition, the laser etc. at the time of forming an image and the energy irradiated with energy on the entire surface are usually of different wavelengths, and the cationically polymerizable compound used in this embodiment is formed by, for example, a laser that forms an image. A compound that does not polymerize is preferred.
[0047]
Further, in this embodiment, such a cationically polymerizable compound is preferably in a liquid state at normal temperature because the radically polymerizable compound is preferably polymerized in a relatively low viscosity composition. . Examples of such cationically polymerizable compounds include "Chemtech. Oct." V. JV Crivello, page 624 (1980), Japanese Patent Application Laid-Open No. Sho 62-149784, Journal of the Adhesion Society of Japan [Vol. 5, pp. 179-187 (1990)] and the like.
[0048]
Specifically, diglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, 1,4-bis (2,3-epoxypropoxyperfluoroisopropyl) cyclohexane, sorbitol polyglycidyl ether, trimethylolpropane polyglycidyl ether, resorcin diglycidyl Ether, 1,6-hexanediol diglycidyl ether, polyethylene glycol diglycidyl ether, phenyl glycidyl ether, paratertiary butylphenyl glycidyl ether, adipic acid diglycidyl ester, orthophthalic acid diglycidyl ester, dibromophenyl glycidyl ether, dibromoneopentyl Glycol diglycidyl ether, 1,2,7,8-diepoxyoctane, 1,6-dimethylol perful Rhohexanediglycidyl ether, 4,4′-bis (2,3-epoxypropoxyperfluoroisopropyl) diphenyl ether, 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, 3,4-epoxycyclohexyl Oxirane, 1,2,5,6-diepoxy-4,7-methanoperhydroindene, 2- (3,4-epoxycyclohexyl) -3 ', 4'-epoxy-1,3-dioxane-5-spirocyclohexane 1,2-ethylenedioxy-bis (3,4-epoxycyclohexylmethane), 4 ', 5'-epoxy-2'-methylcyclohexylmethyl-4,5-epoxy-2-methylcyclohexanecarboxylate, ethylene glycol -Bis (3,4-epoxycyclohexanecarboxylate), bis- (3,4-epoxy (Cicyclohexylmethyl) adipate, di-2,3-epoxycyclopentyl ether, vinyl-2-chloroethyl ether, vinyl-n-butyl ether, triethylene glycol divinyl ether, 1,4-cyclohexanedimethanol divinyl ether, trimethylolethanetri Vinyl ether, vinyl glycidyl ether, and formula
[0049]
[Chemical 1]

[0050]
and,
[0051]
[Chemical formula 2]

[0052]
The compound represented by these is mentioned.
[0053]
Moreover, in this aspect, it is preferable to use the cationically polymerizable compound which has a trifunctional or more polymerizable functional group per molecule as a cationically polymerizable compound among the above. Thereby, since the cross-linking density in the volume hologram layer can be increased, it is possible to improve the foil cut of the volume hologram layer. These cationically polymerizable compounds may be used alone or in combination of two or more.
[0054]
Here, in this embodiment, it is preferable to use the cationically polymerizable compound in the range of 1% by weight to 60% by weight, particularly in the range of 20% by weight to 50% by weight.
[0055]
(2) Radical polymerizable compound
Next, the radically polymerizable compound used in this embodiment will be described. The radical polymerizable compound used in this embodiment is a compound that is polymerized by the action of an active radical generated from a photo radical polymerization initiator system described later, for example, by laser irradiation or the like when forming a volume hologram layer. Although it does not limit, in this aspect, what has at least 1 ethylenically unsaturated double bond in a molecule | numerator is preferable.
[0056]
Here, the volume hologram layer forms an interference fringe by polymerizing a radical polymerizable compound with, for example, laser light or light having excellent coherence, and forms an image. Accordingly, the radical polymerizable compound and the cationic polymerizable compound are selected and used as those having different refractive indexes, and either of them may have a large refractive index. In this embodiment, it is preferable that the average refractive index of the radical polymerizable compound is higher than that of the cationic polymerizable compound from the viewpoint of material selectivity. Specifically, the average refractive index is 0.02 or more. Larger is preferred. This is because when the difference in average refractive index between the radical polymerizable compound and the cationic polymerizable compound is lower than the above value, the refractive index modulation becomes insufficient and it becomes difficult to form a high-definition image. Because. The average refractive index here means the average value of the refractive index measured for the polymer after polymerizing the cationic polymerizable compound or the radical polymerizable compound. Further, the refractive index of this embodiment is a value measured by an Abbe refractometer.
[0057]
Examples of the radical polymerizable compound used in this embodiment include methyl methacrylate, hydroxyethyl methacrylate, lauryl acrylate, N-acryloylmorpholine, 2-ethylhexyl carbitol acrylate, isobornyl acrylate, methoxypropylene glycol acrylate, and 1,6-hexanediol. Diacrylate, tetraethylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, acrylamide, methacrylamide, styrene, 2-bromostyrene, phenyl acrylate, 2-phenoxyethyl acrylate, 2,3- Naphthalenedicarboxylic acid (acryloxyethyl) monoester, methylphenoxye Acrylate, nonylphenoxyethyl acrylate, β-acryloxyethyl hydrogen phthalate, phenoxypolyethylene glycol acrylate, 2,4,6-tribromophenyl acrylate, diphenic acid (2-methacryloxyethyl) monoester, benzyl acrylate, 2,3 -Dibromopropyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-naphthyl acrylate, N-vinylcarbazole, 2- (9-carbazolyl) ethyl acrylate, triphenylmethylthioacrylate, 2- (tricyclo [5,2, 10 ² ・ ⁶ Dibromodecylthio) ethyl acrylate, S- (1-naphthylmethyl) thioacrylate, dicyclopentanyl acrylate, methylene bisacrylamide, polyethylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, diphenic acid (2- Acryloxyethyl) (3-acryloxypropyl-2-hydroxy) diester, 2,3-naphthalene dicarboxylic acid (2-acryloxyethyl) (3-acryloxypropyl-2-hydroxy) diester, 4,5-phenanthrene dicarboxylic Acid (2-acryloxyethyl) (3-acryloxypropyl-2-hydroxy) diester, dibromoneopentyl glycol diacrylate, dipentaerythritol hexaacrylate, 1,3-bis [2-a Riloxy-3- (2,4,6-tribromophenoxy) propoxy] benzene, diethylenedithioglycol diacrylate, 2,2-bis (4-acryloxyethoxyphenyl) propane, bis (4-acryloxydiethoxyphenyl) Methane, bis (4-acryloxyethoxy-3,5-dibromophenyl) methane, 2,2-bis (4-acryloxyethoxyphenyl) propane, 2,2-bis (4-acryloxydiethoxyphenyl) propane, 2,2-bis (4-acryloxyethoxy-3,5-dibromophenyl) propane, bis (4-acryloxyethoxyphenyl) sulfone, bis (4-acryloxydiethoxyphenyl) sulfone, bis (4-acryloxy) Propoxyphenyl) sulfone, bis (4-acryloxyethoxy-3,5-dibromophenyl) sulfone, and A compound obtained by replacing acrylate with methacrylate in the above, and further comprising at least two S atoms in the molecule as described in JP-A-2-247205 and JP-A-2-261808. A double bond containing compound is mentioned, These can be used 1 type or in mixture of 2 or more types.
[0058]
Here, in this embodiment, such a radically polymerizable compound can be used in an amount of 1% to 60% by weight, especially 20% to 50% by weight.
[0059]
(3) Photo radical polymerization initiator system
Next, the radical photopolymerization initiator system used in this embodiment will be described. The radical photopolymerization initiator system used in this embodiment is an initiator capable of generating active radicals and polymerizing the radical polymerizable compound by, for example, laser irradiation when the volume hologram layer is formed. The system is not particularly limited, and examples thereof include U.S. Pat. Nos. 4,766,055, 4,868,092, 4,965,171, and JP-A-54-151024. 58-15,503, 58-29,803, 59-189,340, 60-76735, JP-A-1-28715, and Japanese Patent Application No. 3-5569. And "Proceedings of Conference on Radiation Curing Asia" (PROCEEDINGS OF CONFERENCE ON RADIATION C URING ASIA) "(P.461-477, 1988) and the like.
[0060]
Here, the initiator system means that a sensitizer, which is a component that generally absorbs light, and an active radical generating compound or an acid generating compound can be used in combination. A sensitizer in such a radical photopolymerization initiator system often uses a colored compound such as a dye to absorb visible laser light, but the final hologram requires colorless transparency ( For example, as a sensitizer for use in a head-up display of an automobile or the like, as described in JP-A-58-29803, JP-A-1-287105, and Japanese Patent Application No. 3-5569. It is preferable to use a cyanine dye. Since cyanine dyes are generally easily decomposed by light, the dyes in the hologram are decomposed and absorbed in the visible region by being left exposed for several hours to several days under post-exposure or indoor light or sunlight in this embodiment. This is because a colorless and transparent volume hologram can be obtained. Specific examples of the cyanine dye include anhydro-3,3′-dicarboxymethyl-9-ethyl-2,2′thiacarbocyanine betaine, anhydro-3-carboxymethyl-3 ′, 9-diethyl-2,2 'Thiacarbocyanine betaine, 3,3', 9-triethyl-2,2'-thiacarboxyanine iodine salt, 3,9-diethyl-3'-carboxymethyl-2,2'-thiacarbocyanine iodine salt 3,3 ′, 9-triethyl-2,2 ′-(4,5,4 ′, 5′-dibenzo) thiacarbocyanine iodine salt, 2- [3- (3-ethyl-2-benzothiazoli Den) -1-propenyl] -6- [2- (3-ethyl-2-benzothiazolidene) ethylideneimino] -3-ethyl-1,3,5-thiadiazolium iodine salt, 2-[[ 3-allyl-4-oxo-5- (3-n-propyl-5,6-dimethyl Ru-2-benzothiazolidene) -ethylidene-2-thiazolinylidene] methyl] 3-ethyl-4,5-diphenylthiazolinium-iodine salt, 1,1 ′, 3,3,3 ′, 3′-hexamethyl -2,2'-Indotricarbocyanine iodine salt, 3,3'-diethyl-2,2'-thiatricarbocyanine perchlorate, anhydro-1-ethyl-4-methoxy-3'-carboxy Methyl-5′-chloro-2,2′-quinothiocyanine betaine, anhydro-5,5′-diphenyl-9-ethyl-3,3′-disulfopropyloxacarbocyanine hydroxide triethylamine salt, 2- [ 3- (3-Ethyl-2-benzothiazolidene) -1-propenyl] -6- [2- (3-ethyl-2-benzothiazolidene) ethylideneimino] -3-ethyl-1,3,5 -Thiadiazolium / Yo Salts and the like, can be used in combination with one or more of these.
[0061]
Examples of active radical generating compounds that may be used in combination with cyanine dyes are those described in JP-A-58-29803, JP-A-1-287105, and Japanese Patent Application No. 3-5569. Examples include diaryliodonium salts and 2,4,6-substituted-1,3,5-triazines. The use of diaryliodonium salts is particularly preferred when high photosensitivity is required. Specific examples of the diaryl iodonium salts include diphenyl iodonium, 4,4′-dichlorodiphenyl iodonium, 4,4′-dimethoxydiphenyl iodonium, 4,4′-ditertiary butyl diphenyl iodonium, and 3,3′-dinitrodiphenyl iodonium. Such as chloride, bromide, tetrafluoroborate, hexafluorophosphate, hexafluoroarsenate, hexafluoroantimonate, trifluoromethanesulfonate and the like. Specific examples of 2,4,6-substituted-1,3,5-triazines include 2-methyl-4,6-bis (trichloromethyl) -1,3,5-triazine, 2,4,6. -Tris (trichloromethyl) -1,3,5-triazine, 2-phenyl-4,6-bis (trichloromethyl) -1,3,5-triazine, 2,4-bis (trichloromethyl) -6- ( p-methoxyphenylvinyl) -1,3,5-triazine, 2- (4′-methoxy-1′-naphthyl) -4,6-bis (trichloromethyl) -1,3,5-triazine and the like. .
[0062]
Here, such a radical photopolymerization initiator system is used in an amount of 0.3 to 15% by weight, especially 1 to 10% by weight.
[0063]
(4) Photocationic polymerization initiator system
Next, the photocationic polymerization initiator system used in this embodiment will be described. The photocationic polymerization initiator system used in this embodiment is not particularly limited as long as it generates Bronsted acid or Lewis acid by energy irradiation and polymerizes the cationically polymerizable compound. It is preferable that the radical polymerizable compound is not reacted with, for example, laser or light having excellent coherence, and is exposed to energy irradiated to the entire surface. Thereby, when the radical polymerizable compound is polymerized, the cationic polymerizable compound can be allowed to exist with little reaction, and a large refractive index modulation in the volume hologram layer can be obtained.
[0064]
Here, the photocationic polymerization initiator having low photosensitivity with respect to laser light or light with excellent coherence is initiated by a photocationic polymerization initiator system when thermal analysis is performed under the following conditions. The maximum DSC value resulting from photopolymerization may be 500 mW or less (including 0 mW) per 1 mg of the measurement sample.
Measurement condition
Measuring apparatus: In the SSC5200H thermal analysis system manufactured by Seiko Denshi Kogyo Co., Ltd., the differential scanning calorimetry DSC220 and the light source device UV-1 are used.
Measurement sample: Prepared by dissolving 3% by weight of the target cationic photopolymerization initiator system in UVR-6110 (cationic polymerizable compound) manufactured by Union Carbide (added and dissolved the organic solvent) It may be evaporated.)
Irradiation light: 200 mJ / cm of light adjusted to the same level as laser light or light with excellent coherence using an interference filter (half width of about 10 nm) ² Irradiation
As such a photocationic polymerization initiator system, for example, “UV Curing: Science and Technology”, pages 23-76, edited by S. Peter Pappas, • Technology Marketing Publication and “Comments Inorganic. Chem.”, B. Klingert, M. Reediker and A. L. Ried (B. Klingertk, M. Riedk) and A. Roloff), Vol. 7, No. 3, pp. 109-138 (1988), etc. are used, and one or more of these are used. Rukoto can.
[0065]
Among the above, preferable diaryl iodonium salts include iodonium tetrafluoroborate, hexafluorophosphate, hexafluoroarsenate, hexafluoroantimonate, trifluoromethanesulfonate, 9, Examples thereof include 10-dimethoxyanthracene sulfonate. Preferred triarylsulfonium salts include triphenylsulfonium, 4-tertiarybutyltriphenylsulfonium, tris (4-methylphenyl) sulfonium, tris (4-methoxyphenyl) sulfonium, 4-thiophenyltriphenylsulfonium, and the like. Examples include sulfonium tetrafluoroborate, hexafluorophosphate, hexafluoroarsenate and hexafluoroantimonate, trifluoromethanesulfonate, 9,10-dimethoxyanthracene-2-sulfonate, and the like.
[0066]
Here, such a cationic photopolymerization initiator system is used in an amount of 0.3 to 15% by weight, especially 1 to 10% by weight.
[0067]
(5) Other
In addition to the above-described components, the volume hologram layer of this embodiment contains additives such as a thermal polymerization inhibitor, a silane coupling agent, a plasticizer, a colorant, and a polymer binder as necessary. May be
In this embodiment, it is particularly preferable to contain a polymer binder, and this polymer binder can make the volume hologram layer uniform and keep the image formed by the polymerization of the radical polymerizable compound. It becomes possible.
[0068]
As such a polymer binder, those having good compatibility with the radical polymerizable compound and the cationic polymerizable compound are used. For example, chlorinated polyethylene, polymethyl methacrylate, methyl methacrylate and other (meth) acrylic compounds are used. Copolymers with acid alkyl esters, copolymers of vinyl chloride and acrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, ethyl cellulose, acetyl cellulose, etc. These can be used, and one or more of these can be used in combination.
[0069]
Such a polymer binder is usually used in an amount of 20 to 50% by weight, especially 30 to 40% by weight.
[0070]
(6) Volume hologram layer
Next, the volume hologram layer of this aspect will be described. The volume hologram layer of this embodiment is particularly limited as long as it contains the cationic polymerizable compound, the radical polymerizable compound, the photo radical polymerization initiator, the photo cationic polymerization initiator, and the fine particles. It is not a thing.
[0071]
In order to form such a volume hologram layer, first, a composition in which the above-described components are mixed, for example, a general coating means such as a spin coater, a gravure coater, a comma coater, and a bar coater is formed on a target substrate. Apply by etc. and dry as needed. Further, for example, it may be formed by injecting the composition between two substrates such as a glass plate.
[0072]
In addition, when applying the above materials, a solvent may be used as necessary. Examples of the solvent include ketone solvents such as methyl ethyl ketone, acetone, and cyclohexanone, and esters such as ethyl acetate, butyl acetate, and ethylene glycol diacetate. Solvent, aromatic solvent such as toluene and xylene, cellosolve solvent such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, alcohol solvent such as methanol, ethanol, propanol, ether solvent such as tetrahydrofuran, dioxane, dichloromethane, chloroform, etc. And halogen-based solvents.
[0073]
Next, the above-mentioned radical polymerizable compound is polymerized by exposure to light having excellent coherence (for example, light having a wavelength of 300 nm to 1200 nm) on the layer coated with the above composition. The interference fringes of the target image are recorded. Subsequently, the cationically polymerizable compound remaining unreacted is cured by irradiating the entire surface with light (for example, light of 200 nm to 700 nm) exposed to the photocationic polymerization initiator system. It can be set as the volume hologram layer of this aspect. At this time, the radically polymerizable compound remaining unreacted may be simultaneously cured. In addition, after the image is formed and before the entire surface is irradiated with energy, the diffraction efficiency, the peak wavelength of the diffracted light, the half width, and the like may be changed by processing with infrared rays or heat.
[0074]
In addition, although it is appropriately selected depending on the use and type of the volume hologram layer, the coating amount of the composition is usually 1 g / m. ² ~ 50g / m ² The film thickness of the volume hologram layer is usually 0.1 μm to 50 μm, particularly 1 μm to 20 μm.
[0075]
B. Volume hologram transfer foil
Next, the volume hologram transfer foil of the present invention will be described. The volume hologram transfer foil of the present invention is a volume hologram transfer foil having the volume hologram layer described above, a base material, and a heat-sensitive adhesive layer, wherein the hologram layer is formed on the base material, and the hologram A heat-sensitive adhesive layer is formed on the layer.
[0076]
The volume hologram transfer foil of the present invention includes, for example, as shown in FIG. 1, a base material 1, a hologram layer 2 formed on the base material 1, and a heat-sensitive adhesive layer formed on the hologram layer 2. 3.
[0077]
The volume hologram transfer foil of the present invention bonds the volume hologram layer and the adherend with the heat sensitive adhesive by bringing the heat sensitive adhesive into contact with the adherend and applying heat from the substrate side. The volume hologram layer can be transferred onto the adherend. At this time, according to the present invention, since the volume hologram layer having the above-described good foil cutting property is provided, it is possible to transfer the volume hologram layer to the adherend only on the target portion, and for various applications. The volume hologram transfer foil can be used.
[0078]
For example, as shown in FIG. 2, the transfer is performed such that the heat-sensitive adhesive layer 3 is in contact with the surface of the adherend 6 to which the volume hologram is transferred, and the volume hologram is transferred from the substrate side. For example, the heat-sensitive adhesive layer 3 can be melted and bonded to the portion to be heated and pressed with a heatable mold 7 or the like, and then the substrate 1 is peeled off.
[0079]
Hereinafter, each structure of the volume hologram transfer foil of this invention is demonstrated. The volume hologram layer is the same as that of the volume hologram transfer foil, and the description thereof is omitted here.
[0080]
1. Base material
First, the base material used for the volume hologram transfer foil of the present invention will be described. The base material used in the present invention is one on which the hologram layer is formed. When the volume hologram layer is transferred to an adherend, thermal transfer is performed from the base material side. Therefore, there is no particular limitation as long as the hologram layer can be formed and has resistance to heat and pressure applied during thermal transfer. For example, PET film, polyvinyl chloride (PVC) film , Polyvinylidene chloride film, Polyethylene film, Polypropylene film, Polycarbonate film, Cellophane film, Acetate film, Nylon film, Polyvinyl alcohol film, Polyamide film, Polyamideimide film, Ethylene-vinyl alcohol copolymer film, Polymethyl methacrylate (PMMA) A film, a polyethersulfone film, a polyetheretherketone (PEEK) film, or the like can be used. Further, the thickness of such a substrate is appropriately selected according to the use or type of the volume hologram transfer foil, but is usually in the range of 5 μm to 200 μm, preferably 10 μm to 50 μm. .
[0081]
2. Heat sensitive adhesive layer
Next, the heat-sensitive adhesive layer used in the present invention will be described. The heat-sensitive adhesive layer used in the present invention is a layer formed on the surface of the volume hologram transfer foil opposite to the substrate, and is brought into close contact when the volume hologram layer is transferred onto the adherend by thermal transfer. It is a layer that bonds the volume hologram layer and the adherend by heating or the like.
[0082]
Examples of such a heat-sensitive adhesive layer include ethylene-vinyl acetate copolymer resin (EVA), polyamide resin, polyester resin, polyethylene resin, ethylene-isobutyl acrylate copolymer resin, butyral resin, polyvinyl acetate, and copolymer thereof. Combined resin, cellulose resin, polymethyl methacrylate resin, polyvinyl ether resin, polyurethane resin, polycarbonate resin, polypropylene resin, epoxy resin, phenol resin, styrene butadiene styrene block copolymer (SBS), styrene isoprene styrene block copolymer Thermoplastic resins such as (SIS), styrene ethylene butylene styrene block copolymer (SEBS), and styrene ethylene propylene styrene block copolymer (SEPS) can be used. Among these, a layer that can be heat-sealed at a temperature of 180 ° C. or lower is preferable, and an ethylene-vinyl acetate copolymer resin (EVA) having an acetic acid content of 25% or more is preferably used. Further, the resin may have a heat-sensitive adhesive layer colored as necessary.
[0083]
3. Volume hologram transfer foil
Next, the volume hologram transfer foil of the present invention will be described. The volume hologram transfer foil of the present invention comprises the volume hologram layer, the substrate, and the heat-sensitive adhesive layer, wherein the hologram layer is formed on the substrate, and the hologram layer is formed on the hologram layer. As long as a heat-sensitive adhesive layer is formed on the substrate, the structure and the like are not particularly limited. For example, as shown in FIG. 1 may have a release layer 4 formed on 1, a hologram layer 2 formed on the release layer 4, and a heat-sensitive adhesive layer 3 formed on the hologram layer 2, Still further, for example, as shown in FIG. 4, the base material 1, the hologram layer 2 formed on the base material 1, the reflection layer 5 formed on the hologram layer 2, and the reflection layer 5 It may have the formed heat-sensitive adhesive layer 3.
[0084]
The release layer is a layer that enables the substrate and the volume hologram layer to be easily peeled when the volume hologram layer is transferred onto an adherend using a volume hologram transfer foil. Yes, for example, acrylic resin, vinyl chloride-vinyl acetate copolymer resin, polyester resin, polymethacrylate resin, polyvinyl chloride resin, cellulose resin, silicone resin, chlorinated rubber, casein, various surfactants, metal oxides, etc. From the above, one or a mixture of two or more can be used. Among these, an acrylic resin having a molecular weight of about 20,000 to 100,000, or an acrylic resin and a vinyl chloride-vinyl acetate copolymer resin having a molecular weight of 8000 to 20000, and a polyester resin having a molecular weight of 1,000 to 5,000 as an additive. It is particularly preferred that it comprises a composition containing ~ 5 wt%
In the present invention, it is particularly preferable that the peeling force between the substrate and the volume hologram layer is 1 to 5 g / inch (90 ° peeling). Moreover, it is preferable that the thickness exists in the range of 0.1 micrometer-2 micrometers from surfaces, such as peeling force and foil cutting.
[0085]
Further, the reflection layer is formed between the heat-sensitive adhesive layer and the volume hologram layer. When a metal thin film or the like that reflects light is used for the reflection layer, an opaque type volume hologram is obtained. When a transparent material having a refractive index difference from that of the hologram layer is used, a transparent type volume hologram is obtained, but any of them can be used in the present invention. Such a reflective layer can be formed by a known method such as sublimation, vacuum deposition, sputtering, reactive sputtering, ion plating, or electroplating.
[0086]
In addition, as the metal thin film forming the opaque type hologram, for example, Cr, Ti, Fe, Co, Ni, Cu, Ag, Au, Ge, Al, Mg, Sb, Pb, Pd, Cd, Bi, Sn, Examples thereof include a thin film formed of a metal such as Se, In, Ga, Rb and the like, an oxide, a nitride, or the like alone or in combination of two or more. Among the metal thin films, Al, Cr, Ni, Ag, Au and the like are particularly preferable, and the film thickness is preferably in the range of 1 to 10,000 nm, particularly 20 to 200 nm.
[0087]
On the other hand, as a thin film for forming a 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 hologram forming layer (photo-curing resin 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 The above is optimal. In addition to the above, a metallic reflective film having a thickness of 20 nm or less can be mentioned. As a transparent type reflective layer that is suitably used, acid value titanium (TiO 2) ₂ ), Zinc sulfide (ZnS), Cu • Al composite metal oxide, and the like.
[0088]
Further, in the present invention, a barrier layer can be provided between the release layer and the volume hologram layer, or between or both of the volume hologram layer and the heat-sensitive adhesive layer. Depending on the combination of the photosensitive material, the release layer, and the heat-sensitive adhesive layer used in the production method of the present invention, the low molecular weight component may be transferred from the volume hologram layer to another layer over time, resulting in recording. In some cases, the peak wavelength of the generated hologram shifts to the blue side (short wavelength side), or when the peak wavelength shifts to the release layer or the like, the peelability may be changed. By providing the barrier layer as described above, these obstruction factors can be eliminated.
[0089]
The material used for such a barrier layer is not particularly limited as long as it is a material that exhibits its barrier properties, but the object can usually be achieved by using a transparent organic resin material. Among them, a solvent-free trifunctional or higher functional group, preferably a hexafunctional or higher functional ionizing radiation curable epoxy-modified acrylate resin, urethane-modified acrylate resin, acrylic-modified polyester resin, etc. that reacts with ionizing radiation such as ultraviolet rays and electron beams is used. Can do. In particular, urethane-modified acrylate resins are preferably used because of their high barrier properties.
[0090]
In addition, as these ionizing radiation curable resins, those having a molecular weight in the range of 500 to 2,000 are preferably used in consideration of the coating suitability, the hardness of the finally obtained barrier layer, and the like. Further, since the coating of the barrier layer is basically a solventless system, it can be laminated on any of the volume hologram layer, the release layer, and the heat-sensitive adhesive layer.
[0091]
Moreover, when the adhesiveness of each layer is weak, the adhesion improvement layer etc. may be formed.
[0092]
The volume hologram transfer foil of the present invention as described above may be manufactured by sequentially laminating the base material, the volume hologram layer, and the heat-sensitive adhesive layer, but each member is independent of each other. It may be manufactured by preparing the above steps and laminating them.
[0093]
For example, a volume hologram layer on which an image is recorded, a base material on which a release layer is formed, and a heat-sensitive adhesive layer are prepared and laminated. When each member is prepared by an independent process, for example, a release layer can be formed on a substrate by a dry process, etc., which is preferable in terms of using various materials and manufacturing efficiency. It can be.
[0094]
Also, for example, after forming a volume hologram layer on the substrate (which may have a release layer), a member having an image recorded on the volume hologram layer and a heat-sensitive adhesive layer are prepared, and these are prepared. A laminate or the like may be used. In this case, the composition for forming the volume hologram layer described above is applied onto a support and, for example, irradiated with a laser or the like, the radical polymerizable compound is polymerized, an image is recorded, and the substrate is laminated. Thereafter, the whole surface of the composition is irradiated to form a member in which the volume hologram layer on which the image is recorded and the base material are laminated. Then, the said support body is peeled and it can be set as the method of laminating | stacking, for example, heating a heat sensitive adhesive to 100 to 180 degreeC.
[0095]
Here, the volume hologram laminate of the present invention described above can be applied to, for example, a plastic card, a mobile phone, a cash voucher, a daily necessities, or a CD-ROM package.
[0096]
Moreover, in this invention, the method of controlling the interlayer adhesive force of the said base material and the said volume hologram layer is also included.
[0097]
That is, in the case of having a release layer in the layer configuration of the volume hologram transfer foil described above, an interlayer adhesive force A between the release layer and the support film and an interlayer adhesive force B between the release layer and the hologram forming layer, It is desirable that the relative relationship of the interlayer adhesive force C between the volume hologram layer and the heat-sensitive adhesive layer and the value of B satisfy the following relationship.
Interlayer adhesion: C ≧ B> A
B value: 600 gf / inch
The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.
[0098]
【Example】
Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. In the examples, “parts” and “%” are all based on weight unless otherwise specified.
[0099]
[Method of measuring elongation at break and strength at break]
The elongation at break and the breaking strength of the volume hologram layer in the present invention are stress (strain) -elongation (strain) curves based on values measured under the following conditions by an INSTRON tester “INSTRON 5565” according to JIS K7127-1989. (S-S curve) is recorded, and the elongation at break is obtained from this curve.
[0100]
Measurement atmosphere: 25 ° C or 130 ° C
Test piece: 25 mm width
Pulling speed: 2mm / min
[Preparation of a sample for measurement of breaking strength and elongation at break]
The photosensitive composition for volume hologram recording is
30 parts by weight of cationically polymerizable compound (described as “CM” in the table)
Radical polymerizable compound (described as “RM” in the table) 30 parts by weight
Sensitizer (described as “DYE” in the table) 1 part by weight
Active radical generating compound (described as “PI” in the table) 4 parts by weight
Polymer binder (described as “BP” in the table) 30 parts by weight
5 parts by weight of fine particles
It was prepared with. In this preparation, bis (4-acryloxydiethoxyphenyl) methane is used as the radical polymerizable compound, and 3,9-diethyl-3'-carboxymethyl-2,2'-thiacarbocyanine is used as the radical photopolymerization initiator system. A combination of iodine salt and diphenyliodonium hexafluoroantimonate was used. The photocationic polymerization initiator system was also combined with diphenyliodonium hexafluoroantimonate. As the polymer binder, a copolymer of methyl methacrylate / glycidyl methacrylate (copolymerization ratio 90/10, Mw 50000) was used.
[0101]
30 parts by weight of methyl ethyl ketone (MEK) and 30 parts by weight of methanol were added to 40 parts by weight of the above photosensitive composition for volume hologram recording to obtain a solution of the photosensitive composition for volume hologram recording. The solution of this composition was applied to a 50 μm PET film (Myler 200 manufactured by DuPont) with a gravure coat so that the film thickness after drying was 20 μm, and then a 50 μm PET film was laminated on the coated surface, and a volume hologram A first member having a formation layer was produced.
[0102]
High pressure mercury lamp 4J / cm ² Then, the film was peeled off from the support to prepare a film-like test piece having a width of 20 mm and a length of 50 mm. In addition, when the support surface is released during the film formation, the cured hologram layer can be easily peeled off.
[0103]
[Fabrication evaluation sample preparation]
A first member having a volume hologram forming layer (PET film / volume hologram forming layer / (peelable) PET film), a second member having a peel layer (release layer / PET film), and a first member having a heat-sensitive adhesive layer. Three members (heat-sensitive adhesive layer / peelable PET film) were prepared separately by independent processes.
[0104]
[Production of first member]
Volume hologram recording was performed by adding 30 parts by weight of methyl ethyl ketone (MEK) and 30 parts by weight of methanol to 40 parts by weight of the photosensitive composition for volume hologram recording prepared in the above [Preparation of samples for measuring breaking strength and elongation at break]. A solution of the photosensitive composition for use was obtained. The solution of this composition was applied to a 50 μm PET film (Lumirror T60 (50 μm); manufactured by Toray Industries, Inc.) with a gravure coat so that the film thickness after drying was 10 μm, and surface release treatment was further applied to the coated surface. A PET film (SP-PET (38 μm) manufactured by Tosero Co., Ltd.) was laminated to prepare a first member having a volume hologram forming layer.
[0105]
[Production of second member]
The second member is a PET film (Lumirror T60 (50 μm); manufactured by Toray Industries, Inc.) with a release layer (Haklinis 45-3) using a known coating method so that the film thickness after drying becomes 1 μm. Coated uniformly.
[0106]
[Production of third member]
The third member uses a heat-sensitive adhesive (EC1200; manufactured by Chuo Rika Co., Ltd.) on a surface release-treated PET film (SP-PET (50 μm); manufactured by Tosero Co., Ltd.) using a known coating method. And it applied and produced so that the layer thickness after drying might be set to 2 micrometers.
[0107]
[Production of evaluation samples]
One PET film of the first member having the volume hologram forming layer was peeled off, and the first member was laminated on a volume hologram master prepared in advance. Next, an argon laser beam having a wavelength of 514 nm is irradiated with an illuminance of 1 mW / cm. ² For 60 seconds to form interference fringes. Subsequently, heat treatment was performed at 100 ° C. for 10 minutes, the surface release treatment PET film on one side of the first member was peeled off, and the release layer surface of the second member was laminated at 80 ° C. so as to face the surface of the volume hologram forming layer. . This obtained the laminated body which consists of PET film / release layer / volume hologram formation layer / PET film. Then, the volume hologram forming layer is 2500 mJ / cm with a high pressure mercury lamp. ² Fixing treatment (post-exposure) by irradiation was performed, the PET film in contact with the photosensitive material was peeled off, and the heat-sensitive adhesive layer surface of the third member was laminated at 100 ° C. on the peeled surface. Thereby, the surface release treatment PET film was peeled off from the laminate composed of PET film / release layer / volume hologram layer / thermosensitive adhesive layer / surface release treatment PET film to obtain the volume hologram transfer foil of the present invention.
[0108]
Thereby, the colorless and transparent volume hologram transfer foil which is in a practical range sufficiently in all of the following examples and comparative examples was obtained.
[0109]
[Transfer test method for volume hologram transfer foil]
A volume hologram transfer foil composed of PET film / release layer / volume hologram layer / thermosensitive adhesive layer was prepared. The volume hologram transfer foil of the present invention is superimposed on the surface of an adherend (vinyl chloride card) to which the volume hologram is transferred so that the heat-sensitive adhesive layer of the transfer foil is in contact with the surface, and the volume hologram is transferred. A 10 mm × 10 mm rectangular mold was pressed at 150 ° C. from above the transfer foil. The desired portion of the heat sensitive adhesive layer was melt bonded to provide a transfer layer.
[0110]
The evaluation of foil breakage was performed by confirming whether or not extra transfer foil was adhered to the outer edge of the transfer part. As an evaluation standard, a case where the transfer part and the non-transfer part were clearly broken was marked as ◯, and a case where the break was clearly broken particularly well with reproducibility. Further, among the four sides of the transfer portion, a case where a non-transfer portion is slightly attached to one or two sides is indicated by Δ, and a case where a large non-transfer portion is attached to two or more sides is indicated by ×. The “non-transfer portion” here refers to a portion that is not desired to be attached when the volume hologram is attached from the volume hologram transfer foil.
[0111]
(Examples 1-16, Comparative Examples 1-8)
The combination of the kind of the cationic polymerizable compound and the particle size of the fluorine-based particles (FM108 polymer) was changed to evaluate the breaking strength, elongation at break, and transferability of the volume hologram layer. Each of these conditions and results are shown in Table 1 below. In any of the examples, a volume hologram transfer foil in a practical range was obtained.
[0112]
[Table 1]

[0113]
(Examples 17 to 40, Comparative Examples 9 to 16)
Next, the combination of the kind of the cationic polymerizable compound and the particle size of the fluorine-based particles (PTFE polymer) was changed to evaluate the breaking strength, elongation at break, and transferability of the volume hologram layer. Each of these conditions and results are shown in Table 2 below. In any of the examples, a volume hologram transfer foil in a practical range was obtained.
[0114]
[Table 2]

[0115]
(Comparative Examples 17-24)
Next, particles were not contained, and the type of the cationic polymerizable compound was changed to evaluate the breaking strength, breaking elongation, and transferability of the volume hologram layer. Each of these conditions and results are shown in Table 3 below. In any of the comparative examples, a volume hologram transfer foil in the practical range could not be obtained.
[0116]
[Table 3]

[0117]
(Comparative Examples 25 and 26)
Next, Omnidex 352 is used as the volume hologram recording material, and fluorine-based particles (FM108 polymer: 200 nm, PTFE particles: 200 nm) are added with the composition described in Example 1 of Japanese Patent Application No. 10-97173. The breaking strength, breaking point elongation, and transferability of the volume hologram layer were evaluated. Each of these conditions and results are shown in Table 4 below. In any of the comparative examples, a volume hologram transfer foil in the practical range could not be obtained.
[0118]
[Table 4]

[0119]
(Comparative Example 27, Comparative Example 28)
Next, the omnidex 352 is used as the volume hologram recording material, and the breaking strength and elongation at break of the volume hologram layer containing the respective particles with the composition described in Examples 1 and 2 of Japanese Patent Application No. 10-97173 are disclosed. The transfer suitability was evaluated. Each of these conditions and results are shown in Table 5 below. In any of the comparative examples, a volume hologram transfer foil in the practical range could not be obtained.
[0120]
[Table 5]

[0121]
(Comparative Examples 29-36)
Next, the particles were colloidal silica (MIBK-ST (manufactured by Nissan Chemical Industries)), and the type of the cationic polymerizable compound was changed to evaluate the breaking strength, breaking point elongation, and transferability of the volume hologram layer. Each of these conditions and results are shown in Table 6 below. In any of the comparative examples, a volume hologram transfer foil in the practical range could not be obtained.
[0122]
[Table 6]

[0123]
(Examples 41 and 42)
Next, titania fine particles (R-630 (manufactured by Ishihara Sangyo Co., Ltd.)) were used as the particles, and the type of the cationic polymerizable compound was changed to evaluate the breaking strength, breaking point elongation, and transferability of the volume hologram layer. These conditions and results are shown in Table 7. In any of the examples, a volume hologram transfer foil in a practical range was obtained.
[0124]
[Table 7]

[0125]
The cationically polymerizable compound “CM” used in Tables 1 to 7 is shown in Table 8 below.
[0126]
[Table 8]

[0127]
Moreover, the refractive index of the radically polymerizable compound used above is 1.54, which is larger than the refractive index of the cationically polymerizable compound. The refractive index is a value measured according to JIS K4172 using an Abbe refractometer.
[0128]
Further, the fine particles used in Tables 1 to 7 are shown in Table 9 below.
[0129]
[Table 9]

[0130]
【The invention's effect】
According to the present invention, when the breaking strength and elongation at break at 25 ° C. and 130 ° C. are within the above ranges, for example, when the volume hologram layer is a volume hologram transfer foil, the foil breakage may be caused during thermal transfer. It can be a good volume hologram layer that can be used for various purposes.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view showing an example of a volume hologram transfer foil of the present invention.
FIG. 2 is a schematic sectional view showing an example of the transfer of the volume hologram transfer foil of the present invention.
FIG. 3 is a schematic sectional view showing another example of the volume hologram transfer foil of the present invention.
FIG. 4 is a schematic sectional view showing another example of the volume hologram transfer foil of the present invention.
[Explanation of symbols]
1 ... Base material
2… Volume hologram layer
3 ... Heat-sensitive adhesive layer
4 ... Release layer
5 ... Reflective layer
6 ... Adherent
7 ... Mold

Claims (8)

A cationic polymerizable compound, a radical polymerizable compound, a photo radical polymerization initiator system for polymerizing the radical polymerizable compound, a photo cationic polymerization initiator system for polymerizing the cationic polymerizable compound, and an average particle size of 100 nm to 600 nm. When the layer thickness is 20 μm, the breaking strength at 25 ° C. is in the range of 10 MPa to 30 MPa, the elongation at break is in the range of 0.1% to 3%, and at 130 ° C. A volume hologram layer having a breaking strength in a range of 0.1 MPa to 1 MPa and an elongation at break in a range of 0.1% to 5%,
  Furthermore, the volume hologram layer characterized by containing a polymer binder.   The volume hologram layer according to claim 1, wherein the polymer binder is compatible with the radical polymerizable compound and the cationic polymerizable compound.   The volume hologram layer according to claim 1, wherein the polymer binder is a polymer having a cationic polymerizable group in a side chain or a main chain. The volume hologram layer according to any one of claims 1 to 3, wherein the cationically polymerizable compound is liquid at normal temperature. The volume hologram layer according to any one of claims 1 to 4, wherein the cationic polymerizable compound is a compound having a polymerizable functional group having three or more functional groups per molecule. The volume hologram layer according to any one of claims 1 to 5, wherein a content of the polymer binder is in a range of 20 wt% to 50 wt%. The fine particles, the volume hologram layer according to any one of claims from claim 1, characterized in that contained 1 wt% to 30 wt% to claim 6. A volume hologram transfer foil comprising the volume hologram layer according to any one of claims 1 to 7 , a base material, and a heat-sensitive adhesive layer, wherein the volume hologram is formed on the base material. A volume hologram transfer foil, wherein a layer is formed and a heat-sensitive adhesive layer is formed on the volume hologram layer.

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