JP4185496B2 - Manufacturing method of optical information medium - Google Patents

Description

  The present invention relates to a method for producing an optical information medium, and more particularly, to a method for producing an optical information medium having a composite hard coat layer and excellent in scratch resistance / abrasion resistance and antifouling property / lubricity. In the present invention, the composite hard coat layer is a hard coat layer provided on the surface of the optical information medium responsible for scratch resistance and wear resistance, and a surface provided on the surface of the hard coat layer for antifouling properties and lubricity. Including layers. The optical information medium includes various types such as a read-only optical disc, an optical recording disc, and a magneto-optical recording disc.

In recent years, optical disks have been required to have higher recording capacities for enormous information processing such as moving image information. As the recording density of optical discs increases, recording / reproducing becomes extremely susceptible to scratches on the surface of the light transmission layer on the recording / reproducing laser beam incident side of the optical disc. For this reason, it is necessary to increase the hardness of the light transmission layer surface of the optical disk. Further, in many cases, dirt such as fingerprints, sebum, sweat, cosmetics and the like adhere to the surface of an optical disc depending on the use of the user. Once such dirt is attached, it is not easy to remove, and the attached dirt causes a significant trouble in recording and reproducing information signals. For these reasons, the surface of the light transmission layer on the incident side of the recording / reproducing laser beam of the optical disc is required to be excellent in scratch resistance, wear resistance, antifouling property, and lubricity.
Currently, polycarbonate and methyl methacrylate resin materials are often used as optical materials such as a light transmission layer of an optical information medium from the viewpoint of moldability, transparency, price, and the like. However, such materials have problems such as scratch resistance, abrasion resistance, and antifouling properties against organic stains, and are easily charged due to their high insulation properties. There is also a problem that a large amount of dust adheres to the surface and an error occurs in recording / reproducing optical information.
In order to improve the scratch resistance of the medium surface, it is generally performed to form a transparent and scratch-resistant hard coat on the surface of the light transmission layer of the medium. The hard coat is formed by applying an active energy ray polymerization curable compound having two or more polymerizable functional groups such as (meth) acryloyl groups in the molecule to the surface of the light transmission layer, and applying this to the active energy ray such as ultraviolet rays. It is performed by curing by irradiation. However, although the obtained hard coat is excellent in abrasion resistance as compared with the resin film surface such as polycarbonate and methyl methacrylate, there is a limit to the level of abrasion resistance that can be achieved, and it is not limited to the medium. It does not have sufficient scratch resistance during use. If the resin is harder due to scratch resistance, the shrinkage during curing will increase, and the obtained medium will have a large disc surface warpage. In addition, since such a hard coat is intended only to improve the scratch resistance, it cannot be expected to have an antifouling effect against contaminants such as dust, oil mist in the atmosphere, or fingerprint stains.
As a hard coat having an antifouling property against organic stains, for example, Japanese Patent Application Laid-Open No. 10-110118 proposes kneading a non-crosslinked fluorosurfactant into a hard coat agent. However, when a non-crosslinked fluorosurfactant is added to the hard coat agent, there is a problem that the surfactant gradually disappears when, for example, wiping is performed when the medium is used.
Japanese Patent Application Laid-Open No. 11-213444 discloses that a fluorine-based polymer is applied to the surface of a conventional optical disk substrate such as polycarbonate. However, the fluoropolymer is only physically adsorbed to the substrate surface by van der Waals force, and the adhesion of the fluoropolymer to the substrate surface is extremely poor. Therefore, there is a big problem in the durability of the surface treatment by applying the fluoropolymer.
In Japanese Patent Laid-Open No. 2002-190136, metal chalcogenide fine particles such as silica fine particles are contained in the hard coat to improve the scratch resistance of the hard coat, and water repellent or oil repellent groups are further provided on the hard coat. It is disclosed that a film of a silane coupling agent is provided to improve the antifouling property of the surface.
By the way, when the surface of the medium is made to have a low coefficient of friction, the impact when hard projections come into contact can be slid and released, so that the generation of scratches can be suppressed. Accordingly, it is desired to improve the scratch resistance by reducing the friction coefficient of the hard coat surface. Particularly, in recent years, the numerical aperture (NA) of the objective lens for focusing the recording / reproducing laser beam is increased to 0.7 or more, for example, about 0.85, and the wavelength λ of the recording / reproducing laser beam is increased to about 400 nm. Attempts have been made to reduce the condensing spot diameter of the laser beam by shortening it, thereby recording a large volume of digital data. When the NA is increased in this way, the working distance between the objective lens and the surface of the optical information medium is reduced (for example, when NA is set to about 0.85, the working distance is 100 μm. In this case, the surface of the optical information medium, the objective lens, and the support that supports the objective lens are likely to come into contact with each other during the rotation of the optical information medium. Therefore, it is required to increase the wear resistance of the hard coat surface and at the same time reduce the friction coefficient.

SUMMARY OF THE INVENTION Accordingly, the object of the present invention is to solve the above-mentioned problems of the prior art and to provide an inexpensive method for producing an optical information medium having a surface excellent in scratch resistance, wear resistance, antifouling property and lubricity. There is to do.
SUMMARY OF THE INVENTION As a result of intensive studies, the present inventors have found that a hard coat layer responsible for scratch resistance and wear resistance on the surface of the light transmission layer on the recording / reproducing laser beam incident side, and a surface on the hard coat layer surface. It has been found that an optical information medium having a surface excellent in scratch resistance / abrasion resistance and antifouling property / lubricity can be obtained by providing a composite hard coat layer including a surface layer responsible for antifouling properties and lubricity. It was. The inventors further studied a method for manufacturing an optical information medium, and reached the present invention.
The present invention includes the following inventions.
(1) A method for producing an optical information medium having at least a recording layer, a light transmission layer, a hard coat layer, and a surface layer in this order on a support substrate,
On the light transmission layer, a hard coat agent composition containing an active energy ray-curable component is applied to form an uncured hard coat layer,
On the uncured hard coat layer, a surface layer material containing an active energy ray-curable component having a lubrication and / or antifouling function is formed to form an uncured surface layer,
The formed uncured hard coat layer and the uncured surface layer are irradiated with an electron beam, and then irradiated with ultraviolet rays to cure both layers to form a cured hard coat layer and a cured surface layer. A method of manufacturing an optical information medium. This optical information medium is used so that laser light for recording or reproduction enters through the surface layer, the hard coat layer, and the light transmission layer.
(2) The method for producing an optical information medium according to (1), wherein the active energy ray-curable component contained in the hard coat agent composition is an ultraviolet curable component.
(3) The method for producing an optical information medium according to (1) or (2), wherein the active energy ray-curable component contained in the surface layer material is an electron beam-curable component.
(4) The active energy ray-curable component contained in the surface layer material is an electron beam-curable component and has a silicone-based substituent and / or a fluorine-based substituent, as described in (1) or (2) Manufacturing method of optical information medium.
(5) After forming an uncured hard coat layer, it is dried as necessary, irradiated with ultraviolet rays to form a semi-cured hard coat layer, and then on the semi-cured hard coat layer, for the surface layer The method for producing an optical information medium according to any one of (1) to (4), wherein the material is deposited to form an uncured surface layer. When the surface layer is formed by applying the surface layer material, the surface layer material is applied and then dried.
(6) The method for producing an optical information medium according to (5), wherein an annealing treatment (thermal relaxation treatment) is performed after irradiating the uncured hard coat layer with ultraviolet rays.
(7) The method for manufacturing an optical information medium according to any one of (1) to (6), wherein the surface layer material is formed by coating, the surface layer material is applied, and then heat treatment is performed. .
(8) An active energy ray-curable material is applied on the recording layer and irradiated with ultraviolet rays to form a semi-cured or cured light transmissive layer, and then on the semi-cured or cured light transmissive layer. The manufacturing method of the optical information medium in any one of (1)-(7) which apply | coats a hard-coat agent composition to and forms an uncured hard-coat layer.
(9) The method for manufacturing an optical information medium according to (8), wherein after the light transmission layer is irradiated with ultraviolet rays, annealing treatment (thermal relaxation treatment) is performed.
(10) A light transmissive layer is formed on the recording layer using a resin sheet, and then a hard coating agent composition is applied on the light transmissive layer to form an uncured hard coat layer. (7) The method for producing an optical information medium according to any one of (7).
(11) The method for producing an optical information medium according to any one of (1) to (10), wherein the surface layer has a thickness of 1 nm to 100 nm.
(12) The method for producing an optical information medium according to any one of (1) to (11), wherein the light transmission layer has a thickness of 10 μm to 300 μm.
(13) The method for producing an optical information medium according to any one of (1) to (12), wherein an acceleration voltage of the electron beam in electron beam irradiation is 20 to 100 kV.
The present invention also includes the following inventions.
(14) A method for producing an optical information medium having at least a recording layer on one surface of a light-transmitting support substrate and having a hard coat layer and a surface layer in this order on the other surface of the light-transmitting support substrate. There,
On the other surface of the light-transmitting support substrate, a hard coat agent composition containing an active energy ray-curable component is applied to form an uncured hard coat layer,
On the uncured hard coat layer, a surface layer material containing an active energy ray-curable component having a lubrication and / or antifouling function is formed to form an uncured surface layer,
The formed uncured hard coat layer and the uncured surface layer are irradiated with an electron beam, and then irradiated with ultraviolet rays to cure both layers to form a cured hard coat layer and a cured surface layer. A method of manufacturing an optical information medium. This optical information medium is used so that laser light for recording or reproduction enters through the surface layer, the hard coat layer, and the translucent support substrate.
(15) The method for producing an optical information medium according to (14), wherein the active energy ray curable component contained in the hard coat agent composition is an ultraviolet curable component.
(16) The method for producing an optical information medium according to (14) or (15), wherein the active energy ray-curable component contained in the surface layer material is an electron beam-curable component.
(17) The active energy ray-curable component contained in the surface layer material is an electron beam-curable component and has a silicone-based substituent and / or a fluorine-based substituent, as described in (14) or (15) Manufacturing method of optical information medium.
(18) After forming an uncured hard coat layer, it is dried as necessary, irradiated with ultraviolet rays to form a semi-cured hard coat layer, and then on the semi-cured hard coat layer, for the surface layer The method for producing an optical information medium according to any one of (14) to (17), wherein the material is deposited to form an uncured surface layer.
(19) The method for producing an optical information medium according to (18), wherein an annealing treatment (thermal relaxation treatment) is performed after the uncured hard coat layer is irradiated with ultraviolet rays.
(20) The method for producing an optical information medium according to any one of (14) to (19), wherein the film formation of the surface layer material is performed by coating, the surface layer material is coated, and then the heat treatment is performed. .
(21) The method for producing an optical information medium according to any one of (14) to (20), wherein the surface layer has a thickness of 1 nm to 100 nm.
(22) The method for producing an optical information medium according to any one of (14) to (21), wherein an acceleration voltage of the electron beam in electron beam irradiation is 20 to 100 kV.
In the present invention, the optical information medium includes various media such as a read-only optical disk, an optical recording disk, and a magneto-optical recording disk.
ADVANTAGE OF THE INVENTION According to this invention, the cheap manufacturing method of the optical information medium which has a composite hard-coat layer and is excellent in abrasion resistance, abrasion resistance, antifouling property, and lubricity is provided.

ここで、Ｒは、（メタ）アクリロイル基、ビニル基、メルカプト基、環状エーテル基及びビニルエーテル基の中から選択される少なくとも１つの反応性基を含む置換基であり、ｎ、ｍはそれぞれ重合度であり、ｎは５〜１０００、ｍは２〜１００である。
フッ素系化合物としては、フッ素含有（メタ）アクリレート化合物が挙げられ、具体的には、例えば、２，２，３，３，３−ペンタフルオロプロピル（メタ）アクリレート、２，２，３，３−テトラフルオロプロピル（メタ）アクリレート、２，２，２−トリフルオロエチル（メタ）アクリレート、１Ｈ，１Ｈ，５Ｈ−オクタフルオロペンチル（メタ）アクリレート、３−（パーフルオロ−５−メチルヘキシル）−２−ヒドロキシプロピル（メタ）アクリレート、２−（パーフルオロオクチル）エチルアクリレート、３−パーフルオロオクチル−２−ヒドロキシプロピル（メタ）アクリレート、２−（パーフルオロデシル）エチル（メタ）アクリレート、２−（パーフルオロ−９−メチルオクチル）エチル（メタ）アクリレート、３−（パーフルオロ−７−メチルオクチル）エチル（メタ）アクリレート、２−（パーフルオロ−９−メチルデシル）エチル（メタ）アクリレート、１Ｈ，１Ｈ，９Ｈ−ヘキサデカフルオロノニル（メタ）アクリレート等のフッ化アクリレートが挙げられるが、必ずしもこれらに限定されるものではない。例えば、（メタ）アクリレート基が導入されたパーフルオロポリエーテルなどの高分子化合物、あるいは（メタ）アクリレート基の代わりにビニル基又はメルカプト基を有するフッ素系化合物等も好ましく用いることができる。Ｆｏｍｂｒｉｎ Ｚ ＤＯＬ（アルコール変性パーフルオロポリエーテル（アウジモント社製））のジアクリレート、フルオライトＡＲＴ３、フルオライトＡＲＴ４（共栄社化学）が具体例として挙げられる。
また、フッ素系化合物としては、フッ素含有置換基を有する部位と、環状エーテル基及びビニルエーテル基の中から選択される少なくとも１つの反応性基とを有する化合物が挙げられる。具体的には、３−（１Ｈ，１Ｈ−パーフルオロオクチロキシ）−１，２−エポキシプロパン、３−（１Ｈ，１Ｈ−パーフルオロノニロキシ）−１，２−エポキシプロパン、３−（１Ｈ，１Ｈ−パーフルオロデシロキシ）−１，２−エポキシプロパン、３−（１Ｈ，１Ｈ−パーフルオロウンデシロキシ）−１，２−エポキシプロパン、３−（１Ｈ，１Ｈ−パーフルオロテトラデシロキシ）−１，２−エポキシプロパン、３−（１Ｈ，１Ｈ−パーフルオロヘキサデシロキシ）−１，２−エポキシプロパン、１Ｈ，１Ｈ，６Ｈ，６Ｈ−パーフルオロ−１，６−ヘキサンジオールジグリシジルエーテル、１Ｈ，１Ｈ，８Ｈ，８Ｈ−パーフルオロ−１，８−オクタンジオールジグリシジルエーテル、１Ｈ，１Ｈ，９Ｈ，９Ｈ−パーフルオロ−１，９−ノナンジオールジグリシジルエーテル、１Ｈ，１Ｈ，１０Ｈ，１０Ｈ−パーフルオロ−１，１０−デカンジオールジグリシジルエーテル、１Ｈ，１Ｈ，１２Ｈ，１２Ｈ−パーフルオロ−１，１２−ドデカンジオールジグリシジルエーテル、Ｆｏｍｂｒｉｎ Ｚ ＤＯＬ（アルコール変性パーフルオロポリエーテル（アウジモント社製））のジグリシジルエーテル等が挙げられるが、必ずしもこれらに限定されるものではない。例えば、反応性基として３，４−エポキシシクロヘキシル基等の脂環エポキシ基や、ビニルエーテル基を有する化合物も好ましく用いることができる。
表面層用材料に含まれる活性エネルギー線硬化性化合物としては、１種のみを用いてもよく、２種以上を併用してもよい。表面層用材料に含まれる活性エネルギー線硬化性成分は、電子線硬化性成分であることが好ましい。
また、表面層用材料中には、ハードコート剤組成物におけるのと同様に、必要に応じて、非重合性の希釈溶剤、有機フィラー、無機フィラー、重合禁止剤、酸化防止剤、紫外線吸収剤、光安定剤、消泡剤、レベリング剤、顔料、ケイ素化合物などを含んでいても差し支えない。
次に、光透過層（８）上へのハードコート層（９）と表面層（１０）とからなる複合ハードコート層の形成について説明する。
本発明において、硬化性材料を用いた半硬化又は硬化状態の光透過層（８）表面上に、あるいは光透過性シートからなる光透過層（８）表面上に、前記ハードコート剤組成物を塗布して未硬化のハードコート層を形成する。ハードコート剤の塗布方法は、限定されることなく、スピンコート法、ディップコート法、グラビアコート法等の各種塗布方法を用いるとよい。ハードコート層の硬化後の厚さは、１μｍ以上１０μｍ以下、好ましくは１μｍ以上５μｍ以下となるように形成するとよい。１μｍ未満では、ディスクに充分な表面硬度を与えることができず、１０μｍを超えると、クラックが発生したり、ディスクの反りが大きくなる傾向にある。
光透過層（８）表面にハードコート剤組成物を塗布した後、前記表面層用材料を成膜するのに先立って、未硬化のハードコート層の流動性をなくしておくことが好ましい。未硬化ハードコート層の流動性をなくしておくことによって、これの上に表面層用材料を成膜する際に、ハードコート層の膜厚変動や表面性の悪化を防ぐことができ、表面層用材料を均一に成膜しやすい。
未硬化ハードコート層の流動性をなくすためには、例えば、塗布後に加熱して、ハードコート剤組成物中に含まれていた溶剤をハードコート層から除去するとよい。また、この加熱により、アニール処理（熱緩和処理）を行い、ディスクにたまった硬化収縮による応力を一旦開放させることが好ましい。ここでのアニール処理温度としては、６０℃以上が好ましく、８０℃以上がさらに好ましい。アニール処理温度を８０℃以上とすることで、応力の開放をより早く完全に行うことができる。アニール処理温度の上限は、用いる支持基体の材質にもよるが、一般的に用いる材質のガラス転移温度Ｔｇより、少なくとも１０℃低い温度で行うことが好ましい。また、アニール処理時間は、アニール処理温度にもよるが、１〜５分間が生産効率上からも好ましい。
光透過層に紫外線を照射した後の（すなわち、ハードコート層形成前の）前記したアニール処理を行わなかった場合においても、ハードコート層塗布後のアニール処理を行うことによって、ディスクにたまった応力の開放効果が得られる。この場合にも、アニール処理時間は１〜５分間程度が好ましい。
また、未硬化ハードコート層の流動性をなくすためには、塗布後に必要に応じて加熱して、紫外線を照射してハードコート層を半硬化の状態としてもよい。この際、ハードコート層が完全には硬化しないように、紫外線の照射に注意する。なお、半硬化とは、塗布されたハードコート剤組成物の一部が未反応であることを意味する。従って、ハードコート層の物理的な硬化度は特に問わず、表面の粘着性（タック）が消失していても差し支えない。この際の紫外線照射量は、ハードコート層の厚さにもよるが、例えば１〜５００ｍＪ／ｃｍ^２、好ましくは１〜２００ｍＪ／ｃｍ^２とするとよい。この程度の紫外線照射量で、半硬化状態のハードコート層が得られやすい。ハードコート層に紫外線を照射した後、前記と同様のアニール処理を行うことも好ましい。
次に、未硬化又は半硬化（一部硬化）状態のハードコート層表面上に、前記表面層用材料を成膜して未硬化の表面層を形成する。表面層は、硬化後に得られる厚さが、１ｎｍ以上１００ｎｍ以下、好ましくは５ｎｍ以上５０ｎｍ以下となるように形成するとよい。１ｎｍ未満では、防汚性及び潤滑性の効果があまり得られず、１００ｎｍを超えると、下層のハードコート層の硬度があまり反映されず、耐擦傷性及び耐摩耗性の効果が減少してしまう。
成膜は、前記表面層用材料の塗布により、あるいは蒸着により行うことができる。塗布に際しては、前記表面層用材料を適当な溶剤で希釈し、この塗布液を限定されることなく、スピンコート法、ディップコート法、グラビアコート法、スプレーコート法等の各種塗布方法で塗布するとよい。表面層用材料を塗布した後、加熱処理を行うことが好ましい。加熱処理により、溶剤が蒸発すると共に、表面層用材料が熱によりレベリングされて平滑な表面を得やすくなる。この際の加熱処理温度は６０℃以上が好ましく、８０℃以上がさらに好ましい。加熱処理時間は１〜５分間程度が好ましい。
この際の溶剤としては、未硬化又は半硬化（一部硬化）状態のハードコート層中の活性エネルギー線硬化性化合物を実質的に溶解しない溶剤を選択して用いることが好ましい。前記ハードコート剤組成物を実質的に溶解するか否かは、溶剤の種類だけでなく、塗布方法にも依存する。例えば、表面層用材料の塗布方法としてスピンコート法を用いる際は、多くの場合、スピンコート時に塗布液に含まれる希釈溶剤の大半は揮発するため、前記ハードコート剤組成物をある程度溶解する溶剤を希釈溶剤として用いても、実用上は問題にならない。一方、例えば、表面層用材料の塗布方法としてディップコート法を用いる場合は、未硬化の前記ハードコート層表面と、表面層用材料塗布液との接触時間が長いため、前記ハードコート剤組成物をまったく溶解しないか、ほとんど溶解しない溶剤を用いる必要がある。
このようにして、未硬化又は半硬化（一部硬化）状態のハードコート層と、その表面上に未硬化の表面層とを形成する。
次に、形成された未硬化又は半硬化のハードコート層及び未硬化の表面層に電子線を照射し、その後、紫外線を照射して、前記両層を硬化させる。また、硬化性材料を用いた光透過層（８）が半硬化状態の場合には光透過層（８）を硬化させる。
この際、電子線の照射量は、例えば１〜５０Ｍｒａｄ、好ましくは３〜３０Ｍｒａｄとするとよい。また、電子線の加速電圧は、例えば２０〜１００ｋＶ、好ましくは３０〜７０ｋＶとするとよい。この程度の電子線照射量及び加速電圧で、表面層が硬化されると共に、ハードコート層もある程度硬化され特に表面層の近傍のハードコート層がかなり硬化され、これら両層が界面において強固に密着され、さらに、記録層への電子線によるダメージが起こらないようにすることができる。電子線照射に続く紫外線の照射量は、ハードコート層（９）厚さにもよるが、さらに硬化性材料を用いた光透過層（８）が半硬化状態の場合には光透過層（８）の厚さにもよるが、例えば５００〜５０００ｍＪ／ｃｍ^２、好ましくは１０００〜４０００ｍＪ／ｃｍ^２とするとよい。光透過層（８）が半硬化状態の場合には、光透過層（８）を完全に硬化させるために、より多くの紫外線の照射量が必要となる。このような電子線照射、それに続く紫外線照射によって、完全に硬化し且つ強固に密着されたハードコート層（９）及び表面層（１０）が得られると共に、完全に硬化した光透過層（８）が得られる。
電子線照射、それに続く紫外線照射によって、表面層用材料に含まれる活性エネルギー線硬化性化合物の反応性基同士間での反応や、表面層用材料に含まれる活性エネルギー線硬化性化合物の反応性基と、ハードコート剤組成物に含まれる活性エネルギー線硬化性化合物（無機フィラー表面を修飾している活性エネルギー線反応性基を有する化合物を含む）の反応性基との反応が効率よく起こり、完全に硬化し且つ強固に密着されたハードコート層（９）及び表面層（１０）が得られるものと考えられる。
また、電子線照射、紫外線照射の際には、雰囲気中の酸素濃度が５００ｐｐｍ以下、好ましくは２００ｐｐｍ以下、より好ましくは１０ｐｐｍ以下となるように、窒素などの不活性ガスによるパージを行うことが好ましい。これは、照射雰囲気中で生じる酸素ラジカルに起因する表面の硬化阻害を抑制するためである。あるいは、照射雰囲気中の酸素濃度を制御する代わりに、ハードコート剤組成物及び／又は表面層用材料中に、従来公知の各種酸素阻害抑制剤を添加しておいてもよい。このような酸素阻害抑制剤としては、例えば、日本国特開２０００−１０９８２８号公報、日本国特開２０００−１０９８２８号公報及び日本国特開２０００−１４４０１１号公報に記載されている酸素阻害抑制剤を用いることができる。いうまでもなく、上記酸素阻害抑制剤と、照射雰囲気中の酸素濃度制御とを併用しても差し支えない。
本発明のこのようなプロセスを用いることにより、高硬度のハードコート層（９）上に、その硬度が最表面に反映される程度に薄く、且つ良好な防汚性・潤滑性を有する表面層（１０）を設けると共に、ハードコート層（９）と表面層（１０）の良好な密着性が得られる。
次に、図２を参照して、他の構成例の光情報媒体（以下、光ディスクと略記する）についての本発明の製造方法について説明する。図２は、本発明で製造される光ディスクの他の例の概略断面図である。
図２に例示する光ディスク（３１）は、光透過性支持基体（２０）の一方の面上に有機色素層（２５）と、色素層（２５）上の反射層（２３）と、反射層（２３）上に接着層（２８）を介して貼り合わされた支持基体（２１）とを有し、支持基体（２０）の他方の面上に光透過性ハードコート層（２９）と光透過性表面層（３０）とを有する。この例では、色素層（２５）及び反射層（２３）が記録層を構成する。光ディスク（３１）は、表面層（３０）、ハードコート層（２９）及び支持基体（２０）を通して、記録又は再生のためのレーザー光が入射するように使用される。このような光ディスクとして、追記型のＤＶＤ−Ｒがある。記録／再生レーザー光としては、６５０ｎｍや６６０ｎｍの波長のレーザー光が用いられる。また、青色レーザービーム（４０５ｎｍ程度の波長）が用いられる。
図２に例示した追記型のＤＶＤ−Ｒの他に、光情報媒体として、再生専用型のＤＶＤ−ＲＯＭ、書換え可能型のＤＶＤ−ＲＡＭ等、種々のものが商品化されている。再生専用型のＤＶＤとしては、ＤＶＤ−ＶｉｄｅｏやＤＶＤ−ＲＯＭ等があるが、これらの光記録媒体では、光透過性基板の形成の際に、情報信号が記録されたピットと呼ばれる凹凸が形成され、その上にＡｌなどの金属反射層が形成され、さらに保護層が形成される。保護層上に接着層を介して別の支持基体が貼り合わされて、最終的な光記録媒体となる。書換え可能型のＤＶＤの場合には、前記の相変化型光ディスクについて説明したのと同様に、記録層を構成すれば良い。又、このような構成の媒体において、青色レーザービームを用いて記録／再生する方式も検討されつつある。
支持基体（２０）としては、光透過性の基板が用いられる。光透過性支持基体（２０）は従来、ポリカーボネート樹脂を射出成形し、その表面に種々の情報、例えばプレピットやプレグルーブ等を形成しているが、用いる材料はこれに限定されるものでなく、ポリオレフィン樹脂等の樹脂等も好ましく用いられる。あるいは、ガラス平板に２Ｐ法によりプレピットやプリグルーブを形成することによっても得られる。
支持基体（２０）上に、スピンコート法により溶剤に溶解した有機色素を塗布し、乾燥することで目的の膜厚の有機色素層（２５）を形成する。有機色素としては、種々のシアニン色素、アゾ色素、フタロシアニン色素等から選択する。色素層形成の方法はスピンコート法以外にスプレー法やスクリーン印刷法、さらには蒸着法等も適用可能で、形成する膜厚は用いる色素によって適宜、選択される。
スピンコート法を適用する場合、色素成分を溶媒に溶解して有機色素溶液として使用するが、溶媒としては、色素を十分溶解することができ、また透過性基板に悪影響を及ぼさないものを選択して用いる。濃度は０．０１〜１０重量％程度が好ましい。
溶媒としては、例えばメタノール、エタノール、イソプロピルアルコール、オクタフルオロペンタノール、アリルアルコール、メチルセロソルブ、エチルセロソルブ、テトラフルオロプロパノール等のアルコール系；ヘキサン、ヘプタン、オクタン、デカン、シクロヘキサン、メチルシクロヘキサン、エチルシクロヘキサン、ジメチルシクロヘキサン等の脂肪族または脂環式炭化水素系溶媒；トルエン、キシレン、ベンゼン等の芳香族炭化水素系溶媒；四塩化炭素、クロロホルム、テトラクロロエタン、ジブロモエタン等のハロゲン化炭化水素系溶媒；ジエチルエーテル、ジブチルエーテル、ジイソプロピルエーテル、ジオキサン等のエーテル系溶媒；３−ヒドロキシ−３−メチル−２−ブタノン等のケトン系溶媒；酢酸エチル、乳酸メチル等のエステル系溶媒；水などが挙げられ、これらの中から基板材料を侵さないものを用いることができる。これらは単独で用いてもよく、あるいは２種以上を混合して用いてもよい。
有機色素層の膜厚は、特に限定するものでないが、１０〜３００ｎｍ程度が好ましく、特には６０〜２５０ｎｍ程度である。
有機色素層（２５）上に反射層（２３）を設ける。反射層の材料としては、再生光の波長で反射率の充分高いもの、例えばＡｕ、Ａｇ、Ｃｕ、Ａｌ、Ｎｉ、Ｐｄ、Ｃｒ、Ｐｔ等の元素を単独または合金として用いる。また上記以外でも下記のものを含んでいてもよい。例えばＭｇ、Ｓｅ、Ｈｆ、Ｖ、Ｎｂ、Ｒｕ、Ｗ、Ｍｎ、Ｒｅ、Ｆｅ、Ｃｏ、Ｒｈ、Ｉｒ、Ｚｎ、Ｃｄ、Ｇａ、Ｉｎ、Ｓｉ、Ｇｅ、Ｔｅ、Ｐｂ、Ｐｏ、Ｓｎ、Ｂｉ等の金属および半金属等を挙げることができる。
反射層の形成は、例えば、スパッタ法、イオンプレーティング法、化学蒸着法、真空蒸着法等が挙げられるが、これら例示に限定されるものでない。また、基板の上や反射層の下に反射率の向上や記録特性の改善のために公知の無機系または有機系の中間層、接着層を設けてもよい。反射層の膜厚は特に限定されるものでないが、１０〜３００ｎｍ程度が好ましく、特には８０〜２００ｎｍ程度である。
反射層（２３）の上には通常、保護層としての役割を兼ねた接着層（２８）を介して支持基体（２１）を貼り合わせる。支持基体（２１）は、前記支持基体（２０）と同様のものが用いられる。接着層（２８）の材料としては、両基体（２１）及び（２０）を接着でき、反射層を外力から保護するものであれば特に限定されるものでない。接着剤としては、熱可塑性樹脂、熱硬化性樹脂、紫外線硬化性樹脂等を挙げることができる。熱可塑性樹脂、熱硬化性樹脂などは適当な溶媒に溶解して塗布液を塗布し、乾燥することによって形成することができる。紫外線硬化性樹脂は、そのまま若しくは適当な溶媒に溶解して塗布液を調製した後にこの塗布液を塗布し、紫外線を照射して硬化させることによって形成することができる。紫外線硬化性樹脂としては、例えばウレタンアクリレート、エポキシアクリレート、ポリエステルアクリレート等のアクリレート樹脂を用いることができる。これらの材料は単独で、あるいは混合して用いてもよいし、１層だけでなく多層膜にして用いてもよい。
接着層（２８）の形成方法としては、記録層と同様にスピンコート法やキャスト法などの塗布方法が用いられる。
また、貼り合わせに用いる接着剤は、ホットメルト接着剤、紫外線硬化型接着剤、加熱硬化型接着剤、粘着型接着剤などが用いられ、それぞれに適した方法、例えば、ロールコーター法や、スクリーン印刷法、スピンコート法などが挙げられるが、ＤＶＤ−Ｒの場合、作業性や生産性、ディスク特性などから総合的に判断して紫外線硬化接着剤を用い、スクリーン印刷法やスピンコート法が用いられる。
一方、支持基体（２０）の他方の面上に、ハードコート層（２９）及び表面層（３０）とからなる複合ハードコート層を形成する。ハードコート層（２９）に用いる活性エネルギー線硬化性成分を含むハードコート剤組成物、及び表面層（３０）に用いる潤滑及び／又は防汚機能を有する活性エネルギー線硬化性成分を含む表面層用材料はそれぞれ、図１の光ディスクの製造において述べたのと同様である。
また、ハードコート層（２９）及び表面層（３０）の形成も、図１の光ディスクの製造において述べたのと同様に行うことができる。図２の光ディスクにおいて、ハードコート層（２９）は、厚さ１μｍ以上１０μｍ以下、好ましくは１μｍ以上５μｍ以下となるように形成するとよい。表面層（３０）は、厚さ１ｎｍ以上１００ｎｍ以下となるように形成するとよい。
本発明のプロセスを用いることにより、高硬度のハードコート層（２９）上に、その硬度が最表面に反映される程度に薄く、且つ良好な防汚性・潤滑性を有する表面層（３０）を設けると共に、ハードコート層（２９）と表面層（３０）の良好な密着性が得られる。
以上のような材料及び成膜、硬化方法を用いることにより、耐擦傷性・耐摩耗性及び防汚・潤滑性に優れ、その耐久性も良好な複合ハードコート層を有する光情報媒体が製造される。FIG. 1 is a schematic cross-sectional view of an example of an optical disk manufactured by the present invention.
FIG. 2 is a schematic cross-sectional view of an example of an optical disk manufactured by the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
With reference to FIG. 1, a method for manufacturing an optical information medium (hereinafter abbreviated as an optical disk) of the present invention will be described. Hereinafter, a phase change type optical disc will be described as an example. However, the present invention is not limited to this, and can be widely applied regardless of the type of recording layer, such as a read-only optical disc and an optical disc that can be recorded only once.
FIG. 1 is a schematic cross-sectional view of an example of an optical disk manufactured by the present invention. In FIG. 1, an optical disk (1) has a reflective layer (3) and a second dielectric layer (4) on the surface of a support base (2) on which fine irregularities such as information pits and pregrooves are formed. The phase change recording material layer (5) and the first dielectric layer (6) are provided in this order, and the light transmission layer (8) is provided on the first dielectric layer (6). ) Have a hard coat layer (9) and a surface layer (10). In this example, the reflective layer (3), the second dielectric layer (4), the phase change recording material layer (5) and the first dielectric layer (6) constitute the recording layer (7). Both the hard coat layer (9) and the surface layer (10) are referred to as a composite hard coat layer for convenience. The optical disk (1) is used so that laser light for recording or reproduction enters through the surface layer (10), the hard coat layer (9), and the light transmission layer (8).
Although not shown in the drawing, an optical disc having two or more recording layers in which a recording layer is further provided on the recording layer (7) via a spacer layer is also included in the present invention. In this case, the optical disc has a light transmission layer (8), a hard coat layer (9), and a surface layer (10) on the recording layer farthest from the support base (2).
The support substrate (2) has a thickness of 0.3 to 1.6 mm, preferably 0.5 to 1.3 mm, and has information pits and pregrooves on the surface on which the recording layer (7) is formed. Etc. are formed.
As the support base (2), since the optical disc (1) is used so that the laser light is incident from the light transmitting layer (8) side as described above, it is not necessary to be optically transparent, but transparent As the material, polycarbonate resin, acrylic resin such as polymethyl methacrylate (PMMA), various plastic materials such as polyolefin resin, and the like can be used. Such a material that is easily bent is particularly effective because it can suppress the occurrence of warping of the disk. However, glass, ceramics, metal or the like may be used. In the case of using a plastic material, the concavo-convex pattern is often created by injection molding, and in the case of other than the plastic material, it is formed by a photopolymer method (2P method).
On the support substrate (2), the reflective layer (3) is usually formed by sputtering. As a material for the reflective layer, a metal element, a metalloid element, a semiconductor element, or a compound thereof is used alone or in combination. Specifically, for example, a known reflective layer material such as Au, Ag, Cu, Al, or Pd may be selected. The reflective layer is preferably formed as a thin film having a thickness of 20 to 200 nm.
The second dielectric layer (4), the phase change recording material layer (5), the first dielectric layer (6) directly on the reflective layer (3), or in the absence of the reflective layer, directly on the support substrate (2). ) Are formed in this order by the sputtering method.
The phase change recording material layer (5) is reversibly changed between a crystalline state and an amorphous state by laser light irradiation, and is formed of a material having different optical characteristics between the two states. For example, Ge—Sb—Te, In—Sb—Te, Sn—Se—Te, Ge—Te—Sn, In—Se—Tl, In—Sb—Te, and the like can be given. Further, these materials contain a trace amount of at least one of metals selected from Co, Pt, Pd, Au, Ag, Ir, Nb, Ta, V, W, Ti, Cr, Zr, Bi, In, and the like. It may be added, or a reducing gas such as nitrogen may be added in a trace amount. The thickness of the recording material layer (5) is not particularly limited and is, for example, about 3 to 50 nm.
The second dielectric layer (4) and the first dielectric layer (6) are formed on both sides of the upper and lower surfaces of the recording material layer (5). The second dielectric layer (4) and the first dielectric layer (6) have a function as an interference layer for adjusting optical characteristics as well as mechanical and chemical protection functions of the recording material layer (5). Each of the second dielectric layer (4) and the first dielectric layer (6) may be composed of a single layer or a plurality of layers.
The second dielectric layer (4) and the first dielectric layer (6) are respectively Si, Zn, Al, Ta, Ti, Co, Zr, Pb, Ag, Zn, Sn, Ca, Ce, V, Cu, It is preferably formed from an oxide, nitride, sulfide, fluoride, or a composite thereof containing at least one of metals selected from Fe and Mg. The extinction coefficient k of each of the second dielectric layer (4) and the first dielectric layer (6) is preferably 0.1 or less.
The thickness of the second dielectric layer (4) is not particularly limited, and is preferably about 20 to 150 nm, for example. The thickness of the first dielectric layer (6) is not particularly limited, and is preferably about 20 to 200 nm, for example. By selecting the thicknesses of both dielectric layers (4) and (6) in such a range, the reflection can be adjusted.
On the first dielectric layer (6), the light transmission layer (8) is formed using an active energy ray-curable material or using a light transmission sheet such as a polycarbonate sheet. In the present invention, the active energy ray refers to an electron beam or ultraviolet rays.
The active energy ray curable material used for the light transmission layer (8) is optically transparent, UV curable on the condition that optical absorption and reflection in the used laser wavelength region are small and birefringence is small. Select from materials and electron beam curable materials.
Specifically, the active energy ray curable material is preferably composed of an ultraviolet ray (electron beam) curable compound or a composition for polymerization thereof. Examples of such compounds include ester compounds of acrylic acid and methacrylic acid, acrylic double bonds such as epoxy acrylate and urethane acrylate, allyl double bonds such as diallyl phthalate, and unsaturated double bonds such as maleic acid derivatives. Mention may be made of monomers, oligomers, polymers, etc. containing or introduced in the molecule a group which is crosslinked or polymerized by ultraviolet irradiation such as bonding. These are preferably polyfunctional, particularly trifunctional or more, and may be used alone or in combination of two or more. Moreover, you may use a monofunctional thing as needed.
As the UV curable monomer, a compound having a molecular weight of less than 2000 is preferable, and as the oligomer, a molecular weight of 2000 to 10,000 is preferable. Examples of these include styrene, ethyl acrylate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol methacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, and the like. As pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane di (meth) acrylate, phenol ethylene oxide adduct (Meth) acrylate and the like. In addition, examples of the ultraviolet curable oligomer include oligoester acrylate and an acrylic modified product of urethane elastomer.
The active energy ray curable material may contain a known photopolymerization initiator. The photopolymerization initiator is not particularly required when an electron beam is used as the active energy ray, but is required when ultraviolet rays are used. The photopolymerization initiator may be appropriately selected from ordinary ones such as acetophenone, benzoin, benzophenone, and thioxanthone. Among the photopolymerization initiators, examples of the photoradical initiator include Darocur 1173, Irgacure 651, Irgacure 184, and Irgacure 907 (all manufactured by Ciba Specialty Chemicals). Content of a photoinitiator is about 0.5 to 5 weight% with respect to the said active energy ray hardening component, for example.
Moreover, as an ultraviolet curable material, the composition containing an epoxy resin and a photocationic polymerization catalyst is also used suitably. As the epoxy resin, alicyclic epoxy resins are preferable, and those having two or more epoxy groups in the molecule are particularly preferable. Examples of alicyclic epoxy resins include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, bis- (3,4-epoxycyclohexylmethyl) adipate, bis- (3,4-epoxycyclohexyl) adipate, One or more of 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) cyclohexane-meta-dioxane, bis (2,3-epoxycyclopentyl) ether, vinylcyclohexene dioxide and the like are preferable. . Although there is no restriction | limiting in particular in the epoxy equivalent of an alicyclic epoxy resin, Since favorable sclerosis | hardenability is acquired, it is preferable that it is 60-300, especially 100-200.
Any known photocationic polymerization catalyst may be used without any particular limitation. For example, one or more metal fluoroborate and boron trifluoride complexes, bis (perfluoroalkylsulfonyl) methane metal salts, aryldiazonium compounds, 6A group aromatic onium salts, 5A group aromatic onium salts, A dicarbonyl chelate, a thiopyrylium salt, an MF6 anion (where M is P, As or Sb), a triarylsulfonium complex salt, an aromatic iodonium complex salt, an aromatic sulfonium complex salt, etc. In particular, it is preferable to use one or more of polyarylsulfonium complex salts, aromatic sulfonium salts or iodonium salts of halogen-containing complex ions, aromatic onium salts of 3A group elements, 5A group elements, and 6A group elements. Content of a photocationic polymerization catalyst is about 0.5 to 5 weight% with respect to the said active energy ray hardening component, for example.
As the active energy ray-curable material used for the light transmission layer, a material having a viscosity (25 ° C.) of 1,000 to 10,000 cp is preferable.
In the formation of the light transmission layer (8), the application of the active energy ray-curable material on the first dielectric layer (6) may be performed by a spin coating method. The thickness of the light transmission layer (8) is, for example, about 10 to 300 μm, preferably 20 to 200 μm, particularly 70 to 150 μm, more particularly 75 to 150 μm after curing.
In the present invention, after the active energy ray curable material is applied onto the first dielectric layer (6), the curable material layer is irradiated with ultraviolet rays to be semi-cured or cured, preferably semi-cured. As the light transmissive layer, in the subsequent step, it is preferable to form an uncured hard coat layer by applying the hard coat agent composition onto the semi-cured or cured light transmissive layer.
The amount of UV irradiation at this time depends on the thickness of the light transmitting layer (8) and the type of the active energy ray-curable material, but when obtaining a semi-cured light transmitting layer, for example, 10 to 1500 mJ / cm. ² , Preferably 50 to 1000 mJ / cm ² It is good to do. A semi-cured light-transmitting layer is easily obtained with such an ultraviolet irradiation amount. Semi-cured means that a part of the applied curable material is unreacted. Therefore, the physical curing degree of the light transmission layer is not particularly limited, and the surface tackiness (tack) may be lost. Further, when obtaining a cured light-transmitting layer, for example, 1000 to 5000 mJ / cm. ² , Preferably 2000 to 4000 mJ / cm ² It is good to do. A light-transmitting layer in a cured state can be obtained with such an ultraviolet irradiation amount. In particular, by leaving the light-transmitting layer in a semi-cured state, the fluidity is lost, the interface is not disturbed even by the application of the hard coat agent composition in the next step, and the adhesiveness with the light-transmitting layer is very high. It is preferable because an excellent hard coat layer is formed.
Further, the ultraviolet irradiation at this time may be performed in a plurality of times, and in that case, the integrated irradiation amount of the ultraviolet light may be set in the above range. In addition, the application operation of the active energy ray-curable material may be performed in a plurality of times, and ultraviolet irradiation may be performed after each application operation. By curing the resin stepwise by performing ultraviolet irradiation in a plurality of times, it is possible to reduce the stress due to curing shrinkage that accumulates on the disk at one time, and finally the stress that accumulates on the disk is reduced. As a result, even if the light transmission layer (8) is thick as described above, it is preferable because a disk having excellent mechanical properties can be produced.
It is also preferable to perform annealing treatment (thermal relaxation treatment) after irradiating the light transmission layer with ultraviolet rays. The stress due to curing shrinkage is maximized at the moment when the curable material is cured, and is relieved with the passage of time. Therefore, it is preferable to release the stress caused by the curing shrinkage accumulated in the disk by annealing. Further, when the ultraviolet irradiation is performed in a plurality of times, a more preferable result can be obtained by performing an annealing process between the ultraviolet irradiation and the ultraviolet irradiation subsequent to this irradiation.
The annealing treatment temperature here is preferably 60 ° C. or higher, and more preferably 80 ° C. or higher. By setting the annealing temperature to 80 ° C. or higher, the stress can be released more quickly and completely. Although the upper limit of the annealing temperature depends on the material of the supporting substrate to be used, it is preferably performed at a temperature that is at least 10 ° C. lower than the glass transition temperature Tg of a generally used material. Also, the annealing treatment time is preferably 1 to 5 minutes from the viewpoint of production efficiency, though it depends on the annealing treatment temperature.
Or in this invention, a light transmissive layer can also be formed using a light transmissive resin sheet. In this case, on the first dielectric layer (6), the same active energy ray-curable material as that for the light transmission layer described above is applied to form an uncured resin material layer. A light transmissive sheet as a light transmissive layer (8) is placed on the uncured resin material layer, and then the resin material layer is cured by irradiating active energy rays such as ultraviolet rays. The sheet is adhered to form a light transmission layer (8). As the active energy ray-curable material used for the resin material layer, a material having a viscosity (25 ° C.) of 3 to 500 cp is preferable. The resin material layer may be applied by a spin coating method. The thickness of the resin material layer is, for example, about 1 to 50 μm, preferably 10 to 40 μm after curing.
As the light-transmitting sheet, for example, a polycarbonate sheet having a desired thickness selected from 50 to 300 μm, preferably 50 to 150 μm is used. More specifically, the light transmitting layer (8) is formed by placing a polycarbonate sheet having a desired thickness on an uncured resin material layer in vacuum (0.1 atm or less), The atmosphere is returned to atmospheric pressure, and the resin material layer is cured by irradiating with ultraviolet rays.
A composite hard coat layer comprising a hard coat layer (9) and a surface layer (10) is formed on the light transmission layer (8). First, a hard coat agent composition containing an active energy ray-curable component used for the hard coat layer (9) and a surface containing an active energy ray-curable component having a lubricating and / or antifouling function used for the surface layer (10) The layer material will be described.
The active energy ray-curable component contained in the hard coating composition is UV curable, provided that it is optically transparent, has little optical absorption and reflection in the laser wavelength region used, and has low birefringence. The material and the electron beam curable material are selected, but it is preferable to select from the ultraviolet curable material. That is, the hard coat agent composition is preferably an ultraviolet curable composition. The ultraviolet curable material contained in the hard coat agent composition is selected from the same ultraviolet curable materials as those for the light transmitting layer (8) described above. That is, as hard coating agent compositions, unsaturated compounds such as ester compounds of acrylic acid and methacrylic acid, acrylic double bonds such as epoxy acrylate and urethane acrylate, allylic double bonds such as diallyl phthalate, and maleic acid derivatives A radical polymerizable composition containing a monomer, oligomer, polymer or the like containing or introduced in the molecule a group that crosslinks or polymerizes upon irradiation with ultraviolet rays such as a double bond, and a photopolymerization initiator can be used. Moreover, the cationically polymerizable composition containing an epoxy resin and a photocationic polymerization catalyst is also used suitably as a hard-coat agent composition.
As an active energy ray hardening compound contained in a hard-coat agent composition, only 1 type may be used and 2 or more types may be used together.
The hard coat agent composition may contain an inorganic filler in order to improve the wear resistance, if necessary. Examples of the inorganic filler include silica, alumina, zirconia, titania and the like. The average particle diameter of the inorganic filler is preferably 100 nm or less, and more preferably 50 nm or less, particularly when transparency is required.
Furthermore, in order to further increase the strength and wear resistance of the cured coating, the surface of the inorganic filler is preferably modified with a compound having an active energy ray polymerizable group. Examples of inorganic fillers having an average particle size of 50 nm or less and surface-modified with a compound having an active energy ray polymerizable group include, for example, Japanese Patent Application Laid-Open No. 11-60235, Japanese Patent Application Laid-Open No. 9-100111, and There are reactive silica particles described in Japanese Patent Application Laid-Open No. 2001-187812, which can be preferably used in the present invention. The silica particles described in Japanese Patent Laid-Open No. 11-60235 include a cation-reactive oxetanyl group as a reactive group, and the silica particles described in Japanese Patent Laid-Open No. 9-100111 are As a reactive group, a radical reactive (meth) acryloyl group is included. The silica particles described in Japanese Patent Application Laid-Open No. 2001-187812 include a radical-reactive unsaturated double bond such as a (meth) acryloyl group and a cation-reactive group such as an epoxy group at the same time. By adding such an inorganic filler to the hard coat agent composition, the wear resistance of the hard coat layer can be further improved. The content of the inorganic filler is, for example, about 5 to 80% by weight in the hard coat agent composition (as a solid content). When the inorganic filler is contained in an amount of more than 80% by weight, the film strength of the hard coat layer tends to be weak.
In addition, the hard coat agent composition may further include a non-polymerizable diluent solvent, an organic filler, a polymerization inhibitor, an antioxidant, an ultraviolet absorber, a light stabilizer, an antifoaming agent, a leveling agent, a pigment, A silicon compound may be included.
The material for the surface layer (10) is anti-staining (water-repellent and / or water-repellent) provided that it is optically transparent, has little optical absorption and reflection in the used laser wavelength region, and has low birefringence. The compound is not particularly limited as long as it is a compound having a substituent capable of imparting (oiliness) and / or lubricity and having an active energy ray-polymerizable reactive group. For example, examples of the substituent for imparting antifouling property and / or lubricity include a silicone-based substituent and a fluorine-based substituent. Active energy ray polymerizable reactive groups include active energy ray radical polymerizable reactive groups such as (meth) acryloyl group, vinyl group and mercapto group, and active energy ray cations such as cyclic ether group and vinyl ether group. A polymerizable reactive group is mentioned. Silicone compounds or fluorine compounds having such radically polymerizable reactive groups or cationically polymerizable reactive groups can be used.
As the silicone-based compound, a compound having a site having a silicone-based substituent and at least one reactive group selected from a (meth) acryloyl group, a vinyl group, a mercapto group, a cyclic ether group, and a vinyl ether group More specifically, for example, compounds represented by the following formulas (1) to (3) are exemplified, but the compounds are not necessarily limited thereto.

Here, R is a substituent containing at least one reactive group selected from a (meth) acryloyl group, a vinyl group, a mercapto group, a cyclic ether group and a vinyl ether group, and n and m are polymerization degrees, respectively. N is 5 to 1000, and m is 2 to 100.
Examples of the fluorine-based compound include fluorine-containing (meth) acrylate compounds. Specifically, for example, 2,2,3,3,3-pentafluoropropyl (meth) acrylate, 2,2,3,3- Tetrafluoropropyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, 1H, 1H, 5H-octafluoropentyl (meth) acrylate, 3- (perfluoro-5-methylhexyl) -2- Hydroxypropyl (meth) acrylate, 2- (perfluorooctyl) ethyl acrylate, 3-perfluorooctyl-2-hydroxypropyl (meth) acrylate, 2- (perfluorodecyl) ethyl (meth) acrylate, 2- (perfluoro -9-methyloctyl) ethyl (meth) acrylate, 3- (par Fluorinated acrylates such as uro-7-methyloctyl) ethyl (meth) acrylate, 2- (perfluoro-9-methyldecyl) ethyl (meth) acrylate, 1H, 1H, 9H-hexadecafluorononyl (meth) acrylate However, it is not necessarily limited to these. For example, a polymer compound such as perfluoropolyether having a (meth) acrylate group introduced therein, or a fluorine compound having a vinyl group or a mercapto group instead of the (meth) acrylate group can be preferably used. Specific examples include Fombrin Z DOL (alcohol-modified perfluoropolyether (Audimont)) diacrylate, fluorite ART3, and fluorite ART4 (Kyoeisha Chemical).
Moreover, as a fluorine-type compound, the compound which has a site | part which has a fluorine-containing substituent, and at least 1 reactive group selected from a cyclic ether group and a vinyl ether group is mentioned. Specifically, 3- (1H, 1H-perfluorooctyloxy) -1,2-epoxypropane, 3- (1H, 1H-perfluorononoxy) -1,2-epoxypropane, 3- (1H, 1H-perfluorodecyloxy) -1,2-epoxypropane, 3- (1H, 1H-perfluoroundecyloxy) -1,2-epoxypropane, 3- (1H, 1H-perfluorotetradecyloxy) -1 , 2-epoxypropane, 3- (1H, 1H-perfluorohexadecyloxy) -1,2-epoxypropane, 1H, 1H, 6H, 6H-perfluoro-1,6-hexanediol diglycidyl ether, 1H, 1H, 8H, 8H-perfluoro-1,8-octanediol diglycidyl ether, 1H, 1H, 9H, 9H-perfluoro-1,9-no Diglycidyl ether, 1H, 1H, 10H, 10H-perfluoro-1,10-decanediol diglycidyl ether, 1H, 1H, 12H, 12H-perfluoro-1,12-dodecanediol diglycidyl ether, Fombrin Z Examples thereof include diglycidyl ether of DOL (alcohol-modified perfluoropolyether (Audimont)), but are not necessarily limited thereto. For example, a compound having an alicyclic epoxy group such as 3,4-epoxycyclohexyl group or a vinyl ether group as a reactive group can be preferably used.
As the active energy ray-curable compound contained in the surface layer material, only one type may be used, or two or more types may be used in combination. The active energy ray-curable component contained in the surface layer material is preferably an electron beam-curable component.
In addition, in the surface layer material, as in the hard coat agent composition, if necessary, a non-polymerizable diluent solvent, an organic filler, an inorganic filler, a polymerization inhibitor, an antioxidant, an ultraviolet absorber , Light stabilizers, antifoaming agents, leveling agents, pigments, silicon compounds and the like may be included.
Next, formation of a composite hard coat layer composed of the hard coat layer (9) and the surface layer (10) on the light transmission layer (8) will be described.
In the present invention, the hard coat agent composition is formed on the surface of the light transmissive layer (8) in a semi-cured or cured state using a curable material or on the surface of the light transmissive layer (8) made of a light transmissive sheet. Apply to form an uncured hard coat layer. The coating method of the hard coating agent is not limited, and various coating methods such as a spin coating method, a dip coating method, and a gravure coating method may be used. The thickness of the hard coat layer after curing may be 1 μm or more and 10 μm or less, preferably 1 μm or more and 5 μm or less. If it is less than 1 μm, sufficient surface hardness cannot be given to the disk, and if it exceeds 10 μm, cracks tend to occur or the warp of the disk tends to increase.
After applying the hard coat agent composition to the surface of the light transmission layer (8), it is preferable to eliminate the fluidity of the uncured hard coat layer prior to forming the surface layer material. By eliminating the fluidity of the uncured hard coat layer, it is possible to prevent fluctuations in the thickness of the hard coat layer and deterioration of the surface property when forming the surface layer material on the surface layer. It is easy to form a uniform material.
In order to eliminate the fluidity of the uncured hard coat layer, for example, it is preferable to remove the solvent contained in the hard coat agent composition from the hard coat layer by heating after coating. Further, it is preferable to perform an annealing process (thermal relaxation process) by this heating to once release the stress caused by the curing shrinkage accumulated in the disk. The annealing temperature here is preferably 60 ° C. or higher, and more preferably 80 ° C. or higher. By setting the annealing temperature to 80 ° C. or higher, the stress can be released more quickly and completely. Although the upper limit of the annealing temperature depends on the material of the supporting substrate to be used, it is preferably performed at a temperature that is at least 10 ° C. lower than the glass transition temperature Tg of a generally used material. Also, the annealing treatment time is preferably 1 to 5 minutes from the viewpoint of production efficiency, though it depends on the annealing treatment temperature.
Even when the annealing process after the light transmission layer is irradiated with ultraviolet rays (that is, before the formation of the hard coat layer) is not performed, the stress accumulated on the disk by the annealing process after the hard coat layer is applied. The opening effect is obtained. Also in this case, the annealing time is preferably about 1 to 5 minutes.
In order to eliminate the fluidity of the uncured hard coat layer, the hard coat layer may be semi-cured by applying ultraviolet rays after heating as necessary. At this time, attention is paid to ultraviolet irradiation so that the hard coat layer is not completely cured. Semi-cured means that a part of the applied hard coat agent composition is unreacted. Therefore, the physical curing degree of the hard coat layer is not particularly limited, and the surface adhesiveness (tack) may be lost. The amount of ultraviolet irradiation at this time depends on the thickness of the hard coat layer, but is, for example, 1 to 500 mJ / cm. ² , Preferably 1 to 200 mJ / cm ² It is good to do. With this amount of ultraviolet irradiation, a semi-cured hard coat layer is easily obtained. It is also preferable to perform the same annealing treatment as described above after irradiating the hard coat layer with ultraviolet rays.
Next, the surface layer material is formed on an uncured or semi-cured (partially cured) hard coat layer surface to form an uncured surface layer. The surface layer may be formed so that the thickness obtained after curing is 1 nm to 100 nm, preferably 5 nm to 50 nm. If the thickness is less than 1 nm, the effects of antifouling and lubricity are not obtained so much. If the thickness exceeds 100 nm, the hardness of the lower hard coat layer is not reflected so much, and the effects of scratch resistance and wear resistance are reduced. .
The film formation can be performed by applying the surface layer material or by vapor deposition. In coating, the surface layer material is diluted with an appropriate solvent, and this coating solution is not limited, and can be applied by various coating methods such as spin coating, dip coating, gravure coating, and spray coating. Good. It is preferable to perform heat treatment after applying the surface layer material. By the heat treatment, the solvent evaporates and the surface layer material is leveled by heat, and a smooth surface is easily obtained. The heat treatment temperature at this time is preferably 60 ° C. or higher, more preferably 80 ° C. or higher. The heat treatment time is preferably about 1 to 5 minutes.
As the solvent in this case, it is preferable to select and use a solvent that does not substantially dissolve the active energy ray-curable compound in the uncured or semi-cured (partially cured) hard coat layer. Whether or not the hard coat agent composition is substantially dissolved depends not only on the type of solvent but also on the coating method. For example, when the spin coating method is used as a coating method for the surface layer material, in most cases, most of the dilution solvent contained in the coating solution is volatilized during the spin coating, and therefore the solvent that dissolves the hard coating agent composition to some extent. Even if it is used as a diluting solvent, there is no practical problem. On the other hand, for example, when the dip coating method is used as the coating method for the surface layer material, the contact time between the uncured hard coat layer surface and the surface layer material coating solution is long, so the hard coat agent composition It is necessary to use a solvent that does not dissolve at all or hardly dissolves.
In this way, an uncured or semi-cured (partially cured) hard coat layer and an uncured surface layer are formed on the surface.
Next, the formed uncured or semi-cured hard coat layer and uncured surface layer are irradiated with an electron beam, and then irradiated with ultraviolet rays to cure the two layers. Moreover, when the light transmission layer (8) using a curable material is in a semi-cured state, the light transmission layer (8) is cured.
At this time, the irradiation amount of the electron beam is, for example, 1 to 50 Mrad, preferably 3 to 30 Mrad. The acceleration voltage of the electron beam is, for example, 20 to 100 kV, preferably 30 to 70 kV. With this amount of electron beam irradiation and acceleration voltage, the surface layer is cured and the hard coat layer is also cured to some extent, especially the hard coat layer in the vicinity of the surface layer is considerably cured, and these two layers adhere firmly at the interface. In addition, it is possible to prevent the recording layer from being damaged by the electron beam. Although the irradiation amount of ultraviolet rays following electron beam irradiation depends on the thickness of the hard coat layer (9), when the light transmission layer (8) using a curable material is in a semi-cured state, the light transmission layer (8 ), Depending on the thickness of, for example, 500 to 5000 mJ / cm ² , Preferably 1000 to 4000 mJ / cm ² It is good to do. When the light transmission layer (8) is in a semi-cured state, a larger amount of ultraviolet irradiation is required to completely cure the light transmission layer (8). By such electron beam irradiation and subsequent ultraviolet irradiation, a hard coating layer (9) and a surface layer (10) which are completely cured and firmly adhered are obtained, and a completely cured light transmitting layer (8). Is obtained.
Reaction between reactive groups of the active energy ray-curable compound contained in the surface layer material and reactivity of the active energy ray-curable compound contained in the surface layer material by electron beam irradiation and subsequent ultraviolet irradiation The reaction between the active group and the reactive group of the active energy ray-curable compound (including the compound having an active energy ray reactive group that modifies the inorganic filler surface) contained in the hard coat agent composition occurs efficiently, It is considered that a hard coat layer (9) and a surface layer (10) which are completely cured and firmly adhered are obtained.
Further, at the time of electron beam irradiation and ultraviolet irradiation, it is preferable to purge with an inert gas such as nitrogen so that the oxygen concentration in the atmosphere is 500 ppm or less, preferably 200 ppm or less, more preferably 10 ppm or less. . This is in order to suppress surface hardening inhibition caused by oxygen radicals generated in the irradiation atmosphere. Alternatively, instead of controlling the oxygen concentration in the irradiation atmosphere, various conventionally known oxygen inhibition inhibitors may be added to the hard coat agent composition and / or the surface layer material. As such an oxygen inhibition inhibitor, for example, an oxygen inhibition inhibitor described in Japanese Unexamined Patent Publication No. 2000-109828, Japanese Unexamined Patent Publication No. 2000-109828, and Japanese Unexamined Patent Publication No. 2000-144011. Can be used. Needless to say, the oxygen inhibition inhibitor and oxygen concentration control in the irradiation atmosphere may be used in combination.
By using such a process of the present invention, a surface layer that is thin enough to reflect its hardness on the outermost surface and has good antifouling properties and lubricity on the high hardness hard coat layer (9). While providing (10), good adhesion between the hard coat layer (9) and the surface layer (10) can be obtained.
Next, with reference to FIG. 2, the manufacturing method of the present invention for an optical information medium having another configuration example (hereinafter abbreviated as an optical disk) will be described. FIG. 2 is a schematic cross-sectional view of another example of an optical disc manufactured according to the present invention.
An optical disk (31) illustrated in FIG. 2 includes an organic dye layer (25) on one surface of a light transmissive support base (20), a reflective layer (23) on the dye layer (25), and a reflective layer ( 23) a support base (21) bonded via an adhesive layer (28) on the light-transmitting hard coat layer (29) and a light-transmitting surface on the other surface of the support base (20). Layer (30). In this example, the dye layer (25) and the reflective layer (23) constitute a recording layer. The optical disk (31) is used so that laser light for recording or reproduction enters through the surface layer (30), the hard coat layer (29), and the support base (20). As such an optical disk, there is a write-once type DVD-R. As the recording / reproducing laser beam, a laser beam having a wavelength of 650 nm or 660 nm is used. A blue laser beam (wavelength of about 405 nm) is used.
In addition to the write-once DVD-R illustrated in FIG. 2, various optical information media such as a read-only DVD-ROM and a rewritable DVD-RAM have been commercialized. Reproduction-only DVDs include DVD-Video and DVD-ROM. These optical recording media have irregularities called pits on which information signals are recorded when forming a light-transmitting substrate. A metal reflective layer such as Al is formed thereon, and a protective layer is further formed. Another support substrate is bonded onto the protective layer via an adhesive layer to form a final optical recording medium. In the case of a rewritable DVD, the recording layer may be configured in the same manner as described for the phase change optical disk. In addition, a recording / reproducing system using a blue laser beam in a medium having such a configuration is being studied.
As the support base (20), a light transmissive substrate is used. Conventionally, the light transmissive support base (20) is formed by injection-molding polycarbonate resin, and various information such as pre-pits and pre-grooves are formed on its surface. However, the material used is not limited to this, Resins such as polyolefin resins are also preferably used. Alternatively, it can also be obtained by forming prepits or pregrooves on a glass flat plate by the 2P method.
On the support substrate (20), an organic dye dissolved in a solvent is applied by spin coating and dried to form an organic dye layer (25) having a desired film thickness. The organic dye is selected from various cyanine dyes, azo dyes, phthalocyanine dyes, and the like. As a method for forming the dye layer, a spray method, a screen printing method, and a vapor deposition method can be applied in addition to the spin coating method, and the film thickness to be formed is appropriately selected depending on the dye to be used.
When applying the spin coating method, the dye component is dissolved in a solvent and used as an organic dye solution. Select a solvent that can sufficiently dissolve the dye and does not adversely affect the transparent substrate. Use. The concentration is preferably about 0.01 to 10% by weight.
Examples of the solvent include alcohols such as methanol, ethanol, isopropyl alcohol, octafluoropentanol, allyl alcohol, methyl cellosolve, ethyl cellosolve, tetrafluoropropanol; hexane, heptane, octane, decane, cyclohexane, methylcyclohexane, ethylcyclohexane, Aliphatic or alicyclic hydrocarbon solvents such as dimethylcyclohexane; aromatic hydrocarbon solvents such as toluene, xylene and benzene; halogenated hydrocarbon solvents such as carbon tetrachloride, chloroform, tetrachloroethane and dibromoethane; diethyl Ether solvents such as ether, dibutyl ether, diisopropyl ether, dioxane; ketone solvents such as 3-hydroxy-3-methyl-2-butanone; ethyl acetate, methyl lactate Ester-based solvents; water and the like, can be used from among these does not attack the substrate material. These may be used singly or in combination of two or more.
The thickness of the organic dye layer is not particularly limited, but is preferably about 10 to 300 nm, and particularly about 60 to 250 nm.
A reflective layer (23) is provided on the organic dye layer (25). As a material for the reflective layer, a material having a sufficiently high reflectance at the wavelength of the reproduction light, for example, an element such as Au, Ag, Cu, Al, Ni, Pd, Cr, or Pt is used alone or as an alloy. In addition to the above, the following may be included. For example, Mg, Se, Hf, V, Nb, Ru, W, Mn, Re, Fe, Co, Rh, Ir, Zn, Cd, Ga, In, Si, Ge, Te, Pb, Po, Sn, Bi, etc. A metal, a semimetal, etc. can be mentioned.
Examples of the formation of the reflective layer include a sputtering method, an ion plating method, a chemical vapor deposition method, a vacuum vapor deposition method, and the like, but are not limited to these examples. In addition, a known inorganic or organic intermediate layer or adhesive layer may be provided on the substrate or under the reflective layer in order to improve reflectivity or improve recording characteristics. The thickness of the reflective layer is not particularly limited, but is preferably about 10 to 300 nm, and particularly about 80 to 200 nm.
On the reflective layer (23), a support substrate (21) is usually bonded via an adhesive layer (28) that also serves as a protective layer. The support base (21) is the same as the support base (20). The material of the adhesive layer (28) is not particularly limited as long as it can adhere both the substrates (21) and (20) and protect the reflective layer from external force. Examples of the adhesive include a thermoplastic resin, a thermosetting resin, and an ultraviolet curable resin. A thermoplastic resin, a thermosetting resin, etc. can be formed by dissolving in an appropriate solvent, applying a coating solution, and drying. The ultraviolet curable resin can be formed by preparing a coating solution as it is or by dissolving in an appropriate solvent, and then applying the coating solution and curing it by irradiating with ultraviolet rays. As the ultraviolet curable resin, for example, acrylate resins such as urethane acrylate, epoxy acrylate, and polyester acrylate can be used. These materials may be used alone or in combination, and may be used as a multilayer film as well as a single layer.
As a method for forming the adhesive layer (28), a coating method such as a spin coat method or a cast method is used as in the recording layer.
In addition, as the adhesive used for bonding, a hot melt adhesive, an ultraviolet curable adhesive, a heat curable adhesive, an adhesive adhesive, or the like is used, and a method suitable for each, for example, a roll coater method, a screen The printing method, spin coating method, etc. are mentioned. In the case of DVD-R, an ultraviolet curing adhesive is used based on comprehensive judgment from workability, productivity, disk characteristics, etc., and screen printing method or spin coating method is used. It is done.
On the other hand, a composite hard coat layer comprising a hard coat layer (29) and a surface layer (30) is formed on the other surface of the support substrate (20). Hard coat agent composition containing an active energy ray-curable component used for the hard coat layer (29), and surface layer containing an active energy ray-curable component having a lubricating and / or antifouling function used for the surface layer (30) Each material is the same as described in the manufacture of the optical disk of FIG.
Further, the hard coat layer (29) and the surface layer (30) can be formed in the same manner as described in the production of the optical disk of FIG. In the optical disk of FIG. 2, the hard coat layer (29) may be formed to have a thickness of 1 μm to 10 μm, preferably 1 μm to 5 μm. The surface layer (30) is preferably formed to have a thickness of 1 nm to 100 nm.
By using the process of the present invention, on the hard coat layer (29) having a high hardness, the surface layer (30) is thin enough to reflect its hardness on the outermost surface and has good antifouling properties and lubricity. In addition, good adhesion between the hard coat layer (29) and the surface layer (30) can be obtained.
By using the materials and film formation and curing methods as described above, an optical information medium having a composite hard coat layer having excellent scratch resistance, abrasion resistance, antifouling, and lubricity and excellent durability is produced. The

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.
[Example 1: Light transmission layer made of active energy ray curable material]
An optical recording disk sample having the layer structure shown in FIG. 1 was produced as follows.
A reflective layer (3) having a thickness of 100 nm made of Al ₉₈ Pd ₁ Cu ₁ (atomic ratio) on the surface of a disk-shaped support substrate (2) (made of polycarbonate, diameter 120 mm, thickness 1.1 mm) on which grooves are formed Was formed by sputtering. The depth of the groove was λ / 6 expressed by the optical path length at the wavelength λ = 405 nm. The recording track pitch in the groove recording system was 0.32 μm.
Next, a second dielectric layer (4) having a thickness of 20 nm was formed on the surface of the reflective layer (3) by sputtering using an Al ₂ O ₃ target. A recording material layer (5) having a thickness of 12 nm was formed on the surface of the second dielectric layer (4) by sputtering using an alloy target made of a phase change material. The composition (atomic ratio) of the recording material layer (5) was Sb ₇₄ Te ₁₈ (Ge ₇ In ₁ ). The recording material layer (5) surface, ZnS (80 mol%) - by _SiO 2 (20 mol%) sputtering method using a target, thereby forming a first dielectric layer having a thickness of 130 nm (6).
Next, the following ultraviolet curable material was applied to the surface of the first dielectric layer (6) by spin coating, and then partially cured by irradiation with ultraviolet rays (irradiation amount: 500 mJ / cm ² ). A light transmission layer (8) was formed so as to have a thickness of 98 μm after complete curing.
(Light transmission layer: Composition of UV curable material)
50 parts by weight of urethane acrylate oligomer (Made by Mitsubishi Rayon Co., Ltd., Diabeam UK6035)
Isocyanuric acid EO-modified triacrylate 10 parts by weight (Aronix M315, manufactured by Toa Gosei Co., Ltd.)
Isocyanuric acid EO-modified diacrylate 5 parts by weight (manufactured by Toa Gosei Co., Ltd., Aronix M215)
Tetrahydrofurfuryl acrylate 25 parts by weight Photopolymerization initiator (1-hydroxycyclohexyl phenyl ketone) 3 parts by weight Next, an ultraviolet / electron beam curable hard coating agent having the following composition is formed on the light transmission layer (8) by spin coating. After coating, the diluted solvent inside the film was removed by heating at 80 ° C. for 3 minutes in the atmosphere to form an uncured hard coat layer (9).
(Composition of hard coating agent)
Reactive group-modified colloidal silica (dispersion medium: propylene glycol monomethyl ether acetate, nonvolatile content: 40% by weight) 100 parts by weight dipentaerythritol hexaacrylate 48 parts by weight tetrahydrofurfuryl acrylate 12 parts by weight propylene glycol monomethyl ether acetate 40 parts by weight ( Non-reactive diluent solvent)
Irgacure 184 (polymerization initiator) 5 parts by weight Next, 0.5% (percentage by mass) of Fluorinert FC-77 (Sumitomo) of perfluoropolyether diacrylate (Audmont Co., Ltd., Fombrin Z DOL acrylic modified product, molecular weight of about 2000) (3M) solution was applied onto the uncured hard coat layer (9) by spin coating, and dried at 80 ° C. for 3 minutes to form an uncured surface layer (10).
Next, the hard coat layer (9) and the surface layer (10) were simultaneously cured by irradiating an electron beam under a nitrogen stream. Using an electron beam irradiation apparatus Min-EB (manufactured by Toyo Ink Manufacturing Co., Ltd.), the electron beam acceleration voltage was 50 kV and the irradiation dose was 100 kGy (10 Mrad). The oxygen concentration in the irradiation atmosphere was 80 ppm. Furthermore, the light transmission layer (8) and the hard coat layer (9) were completely cured by irradiating ultraviolet rays (irradiation amount: 3000 mJ / cm ² ) under a nitrogen stream. The oxygen concentration in the irradiation atmosphere was 80 ppm. The film thickness of the hard coat layer (9) was 2.1 μm, and the film thickness of the surface layer (10) was about 25 nm. The film thickness of the surface layer was measured by fluorescent X-ray analysis (XRF) using perfluoropolyether (Daikin Kogyo Co., Ltd., demnum) as a standard substance. In this way, a disk sample was obtained.

After the formation of the uncured hard coat layer (9) and before the application of the surface layer (10), ultraviolet irradiation (irradiation amount: 80 mJ / cm ² ) was performed, and the hard coat layer (9) was partially cured. In the same manner as in Example 1, a disk sample was obtained. The film thickness of the hard coat layer (9) was 2.1 μm, and the film thickness of the surface layer (10) was about 25 nm.

以上の測定結果を表１に示す。
表１から、実施例１〜４のディスクサンプルは、耐摩耗性に優れ、防汚耐久性も極めて良好であった。
比較例１においては、最後の紫外線照射を行わなかったために、耐摩耗性に著しく劣っていた。比較例２においては、電子線照射を行わなかったために、防汚性に著しく劣っていた。比較例３においては、ハードコート層の完全硬化後に表面層を塗布したために、防汚性に著しく劣っていた。
上記実施例では、相変化型光ディスクへの複合ハードコート層の付与を示した。しかしながら、本発明は、記録層が相変化型の光ディスクのみならず、再生専用型光ディスクや、追記型光ディスクにも適用される。そのため、前述の実施例はあらゆる点で単なる例示にすぎず、限定的に解釈してはならない。さらに、請求の範囲の均等範囲に属する変更は、すべて本発明の範囲内のものである。The ultraviolet ray irradiation amount in the formation of the light transmission layer (8) was changed to 3000 mJ / cm ² , and the light transmission layer (8) was completely cured before application of the hard coating agent, and the uncured hard coat layer (9 ), And before application of the surface layer (10), ultraviolet irradiation (irradiation amount: 80 mJ / cm ² ) was performed, and the hard coat layer (9) was partially cured, as in Example 1. A disk sample was obtained. The film thickness of the hard coat layer (9) was 2.1 μm, and the film thickness of the surface layer (10) was about 25 nm.
[Example 4: Light transmission layer by light transmission sheet]
The same processes as in Example 1 were performed until the first dielectric layer (6) was formed.
On the surface of the first dielectric layer (6), a radical polymerizable ultraviolet curable resin solution (Mitsubishi Rayon Co., Ltd., 4X108E, solvent: butyl acetate) is applied by spin coating, and the thickness after curing is 2.0 μm. A resin material layer was formed so that
Next, a polycarbonate sheet having a thickness of 100 μm was placed on the resin material layer in a vacuum (0.1 atm or less). As the polycarbonate sheet, Pure Ace manufactured by Teijin Ltd. manufactured by the casting method was used. Next, the pressure was returned to atmospheric pressure, and the resin material layer was cured by irradiating with ultraviolet rays, whereby the polycarbonate sheet was adhered, and this was used as the light transmission layer (8).
Subsequent operations were performed in the same manner as in Example 1. That is, an uncured hard coat layer (9) is formed on the light transmission layer (8), then an uncured surface layer (10) is formed, and then hardened by irradiation with an electron beam in a nitrogen stream. The coat layer (9) and the surface layer (10) were simultaneously cured. The electron beam acceleration voltage was 50 kV and the irradiation dose was 100 kGy (10 Mrad). The oxygen concentration in the irradiation atmosphere was 80 ppm. Furthermore, the hard coat layer (9) was completely cured by irradiating ultraviolet rays under a nitrogen stream (irradiation amount: 3000 mJ / cm ² ). The oxygen concentration in the irradiation atmosphere was 80 ppm. The film thickness of the hard coat layer (9) was 2.1 μm, and the film thickness of the surface layer (10) was about 25 nm.
[Comparative Example 1]
A disk sample was obtained in the same manner as in Example 1 except that the last ultraviolet irradiation (irradiation amount: 3000 mJ / cm ² ) was not performed.
[Comparative Example 2]
A disk sample was obtained in the same manner as in Example 1 except that the electron beam irradiation [irradiation dose: 100 kGy (10 Mrad)] was not performed.
[Comparative Example 3]
After the formation of the uncured hard coat layer (9) and before the application of the uncured surface layer (10), ultraviolet irradiation (irradiation amount: 3000 mJ / cm ² ) was performed to completely cure the hard coat layer (9). A disk sample was obtained in the same manner as in Example 1.
(Evaluation of disk sample surface)
The following performance tests were performed on the disk samples prepared in Examples 1 to 4 and Comparative Examples 1 to 3.
(1) Abrasion resistance Using steel wool # 0000, the degree of scratches produced when the hard coat surface of each disk sample was slid 20 times at a load of 4.9 N / cm ² was visually judged. Judgment criteria are as follows.
○: No scratches Δ: Slight scratches ×: Scratches generated (2) Antifouling property (antifouling durability)
The contact angle with pure water on the hard coat surface of each disk sample was measured. The measurement was performed after sliding the sample surface with a waste cloth containing a solvent. The sliding conditions were as follows. That is, a nonwoven fabric (Asahi Kasei Kogyo Co., Ltd., Bencott Lint Free CT-8) was impregnated with acetone and slid 50 times at a load of 4.9 N / cm ² . The contact angle was measured using a contact angle meter CA-D manufactured by Kyowa Interface Science Co., Ltd. in an environment with an air temperature of 20 ° C. and a relative humidity of 60%.

The above measurement results are shown in Table 1.
From Table 1, the disk samples of Examples 1 to 4 were excellent in abrasion resistance and extremely excellent in antifouling durability.
In Comparative Example 1, since the last ultraviolet irradiation was not performed, the abrasion resistance was remarkably inferior. In Comparative Example 2, since the electron beam irradiation was not performed, the antifouling property was remarkably inferior. In Comparative Example 3, since the surface layer was applied after the hard coat layer was completely cured, the antifouling property was remarkably inferior.
In the above embodiment, the application of the composite hard coat layer to the phase change type optical disk was shown. However, the present invention is applied not only to a phase change type optical disc but also to a read-only optical disc and a write once optical disc. For this reason, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. Furthermore, all modifications belonging to the equivalent scope of the claims are within the scope of the present invention.

Claims (13)

A method for producing an optical information medium having at least a recording layer, a light transmission layer, a hard coat layer, and a surface layer in this order on a support substrate,
On the light transmission layer, a hard coat agent composition containing an active energy ray-curable component is applied to form an uncured hard coat layer,
On the uncured hard coat layer, a surface layer material containing an active energy ray-curable component having a lubrication and / or antifouling function is formed to form an uncured surface layer,
The formed uncured hard coat layer and the uncured surface layer are irradiated with an electron beam, and then irradiated with ultraviolet rays to cure both layers to form a cured hard coat layer and a cured surface layer. A method of manufacturing an optical information medium. The method for producing an optical information medium according to claim 1, wherein the active energy ray-curable component contained in the hard coat agent composition is an ultraviolet curable component. The method for producing an optical information medium according to claim 1, wherein the active energy ray-curable component contained in the surface layer material is an electron beam-curable component. The active energy ray-curable component contained in the surface layer material is an electron beam-curable component, and has a silicone-based substituent and / or a fluorine-based substituent. Production method. After forming an uncured hard coat layer, it is dried as necessary, irradiated with ultraviolet rays as a semi-cured hard coat layer, and then the surface layer material is placed on the semi-cured hard coat layer. The method for producing an optical information medium according to claim 1, wherein the uncured surface layer is formed by film formation. 6. The method for manufacturing an optical information medium according to claim 5, wherein an annealing treatment (thermal relaxation treatment) is performed after the uncured hard coat layer is irradiated with ultraviolet rays. 2. The method for producing an optical information medium according to claim 1, wherein the surface layer material is formed by coating, the surface layer material is coated, and then heat treatment is performed. On the recording layer, an active energy ray-curable material is applied, irradiated with ultraviolet rays to form a semi-cured or cured light transmissive layer, and then hard coated on the semi-cured or cured light transmissive layer. The method for producing an optical information medium according to claim 1, wherein an uncured hard coat layer is formed by applying an agent composition. The method for manufacturing an optical information medium according to claim 8, wherein annealing (thermal relaxation treatment) is performed after the light transmission layer is irradiated with ultraviolet rays. The light transmission layer is formed on the recording layer by using a resin sheet, and then the hard coating agent composition is applied on the light transmission layer to form an uncured hard coat layer. The manufacturing method of the optical information medium as described. The method for producing an optical information medium according to claim 1, wherein the surface layer has a thickness of 1 nm to 100 nm. The method for manufacturing an optical information medium according to claim 1, wherein the light transmission layer has a thickness of 10 µm to 300 µm. A method for producing an optical information medium having at least a recording layer on one surface of a light transmissive support substrate, and having a hard coat layer and a surface layer in this order on the other surface of the light transmissive support substrate,
On the other surface of the light-transmitting support substrate, a hard coat agent composition containing an active energy ray-curable component is applied to form an uncured hard coat layer,
On the uncured hard coat layer, a surface layer material containing an active energy ray-curable component having a lubrication and / or antifouling function is formed to form an uncured surface layer,
The formed uncured hard coat layer and the uncured surface layer are irradiated with an electron beam, and then irradiated with ultraviolet rays to cure both layers to form a cured hard coat layer and a cured surface layer. A method of manufacturing an optical information medium.

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