WO2011040375A1 - 光情報記録媒体用粘着シート、光情報記録媒体ならびに光情報記録媒体再生方法および装置 - Google Patents
光情報記録媒体用粘着シート、光情報記録媒体ならびに光情報記録媒体再生方法および装置 Download PDFInfo
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- WO2011040375A1 WO2011040375A1 PCT/JP2010/066718 JP2010066718W WO2011040375A1 WO 2011040375 A1 WO2011040375 A1 WO 2011040375A1 JP 2010066718 W JP2010066718 W JP 2010066718W WO 2011040375 A1 WO2011040375 A1 WO 2011040375A1
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- information recording
- optical information
- recording medium
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- layer
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
- G11B7/252—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers
- G11B7/256—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of layers improving adhesion between layers
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/24018—Laminated discs
- G11B7/24024—Adhesion or bonding, e.g. specific adhesive layers
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/2403—Layers; Shape, structure or physical properties thereof
- G11B7/24056—Light transmission layers lying on the light entrance side and being thinner than the substrate, e.g. specially adapted for Blu-ray® discs
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/2403—Layers; Shape, structure or physical properties thereof
- G11B7/24065—Layers assisting in recording or reproduction below the optical diffraction limit, e.g. non-linear optical layers or structures
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/21—Circular sheet or circular blank
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/28—Web or sheet containing structurally defined element or component and having an adhesive outermost layer
- Y10T428/2852—Adhesive compositions
- Y10T428/2878—Adhesive compositions including addition polymer from unsaturated monomer
- Y10T428/2887—Adhesive compositions including addition polymer from unsaturated monomer including nitrogen containing polymer [e.g., polyacrylonitrile, polymethacrylonitrile, etc.]
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/28—Web or sheet containing structurally defined element or component and having an adhesive outermost layer
- Y10T428/2852—Adhesive compositions
- Y10T428/2878—Adhesive compositions including addition polymer from unsaturated monomer
- Y10T428/2891—Adhesive compositions including addition polymer from unsaturated monomer including addition polymer from alpha-beta unsaturated carboxylic acid [e.g., acrylic acid, methacrylic acid, etc.] Or derivative thereof
Definitions
- the present invention relates to an optical information recording medium for optically recording or reproducing information, an adhesive sheet used for manufacturing the optical information recording medium, an optical information recording medium reproducing method for reproducing the optical information recording medium, and optical information
- the present invention relates to a recording medium playback apparatus.
- optical information recording media are increasingly required to increase the information recording density in order to process a huge amount of information such as video.
- One of the solutions is super-resolution technology.
- Super-resolution technology occurs when information is recorded on a pre-pit or recording type optical information medium having a length less than the optical resolution limit (determined by the laser wavelength and the numerical aperture of the optical system) of the reproducing apparatus. This is a technique for reproducing a recording mark). This makes it possible to record using a mark having a short length, thereby increasing a substantial information recording density.
- Patent Document 1 and Patent Document 2 describe a method of substantially reducing the spot diameter by forming a mask layer on an optical information recording medium.
- Patent Document 1 discloses an optical disk apparatus that performs recording and reproduction using a reflectance change caused by uneven prepits formed on a substrate of an optical disk medium, on a medium layer on which a signal is recorded (The laser beam is irradiated on the disk surface from the objective lens on the side that is irradiated with the laser beam at room temperature. The laser beam is not absorbed due to the increase in temperature due to the reproduction laser power. It is disclosed to form a temperature-dependent optical shutter layer that absorbs reproduction laser light.
- Patent Document 1 in an optical disc apparatus that records and reproduces information using a change in reflectance due to a phase change of a recording material, laser light is emitted from an objective lens on the disc surface (on the disc surface).
- the irradiation side absorbs the reproduction laser beam at room temperature, stops absorbing the reproduction laser beam due to the temperature rise due to the reproduction laser power, and absorbs the reproduction laser beam again due to the temperature drop after passing through the reproduction focusing spot. It is also disclosed to form a dependent light shutter layer.
- Patent Document 2 in an optical information recording medium having a recording film on a substrate, light is not transmitted before the reading light is irradiated to the position before the reading light or recording light is incident on the recording film. It is disclosed to provide an optical shutter layer containing as a main component a thermochromic substance that is in a colored state and rises in temperature at the central portion of the irradiated portion when irradiated with readout light, and becomes partially transparent and light transmissive. ing.
- thermochromic material and phase change material forming the mask layer exhibit a mask effect by melting when the temperature is raised to a certain temperature or higher.
- the melted substance has high fluidity, and its initial composition and shape are likely to change.
- the mask effect is gradually increased due to a shift in the composition and shape of the mask layer when repeated recording and reproduction are performed.
- the conventional optical information recording medium has insufficient durability.
- Patent Document 3 and Patent Document 4 disclose an invention in which a metal oxide whose reflectance and / or transmittance changes according to a change in temperature is used for the mask layer. .
- repeated recording and reproduction are performed by forming a mask layer with a material such as a metal oxide (preferably zinc oxide) that does not melt due to a temperature rise during recording or reproduction.
- a metal oxide preferably zinc oxide
- the layer in contact with the information recording layer as the mask layer has a low thermal conductivity in order to promote the temperature rise, and between the light-transmitting base film and the information recording layer. It is described that it is preferable to join the two with a transparent resin layer interposed therebetween.
- an optical information recording medium described in Patent Document 5 a transparent base film, a transparent resin layer, an information recording layer, and a substrate are laminated, and a mask layer constituting the information recording layer is always transparent. It will be in contact with the resin layer. For this reason, the performance of the transparent resin layer is such that the adhesion with the metal oxide constituting the information recording layer is sufficiently maintained, and the embedding property (trackability) with respect to the uneven information recording layer is provided. It is required not to adversely affect the product.
- a method of containing an acidic group as a main component of the transparent resin layer is used.
- corrosion occurs in the metal oxide film in contact with the transparent resin layer, particularly under high temperature and high humidity.
- the acidic group is not contained, the corrosiveness can be suppressed, but on the other hand, the adhesive force to the metal is dramatically reduced.
- Patent Document 6 proposes an adhesive that does not contain a carboxyl group-containing copolymerizable monomer and contains a nitrogen atom-containing copolymerizable monomer.
- the (meth) acrylic acid ester copolymer synthesized in Patent Document 6 is not touched on the physical property behavior of the transparent resin layer at all, and in the configuration given in the examples, in a rapid environmental change Cracks occur in the metal oxide film forming the information recording layer.
- the present invention has been made in view of such a problem, and a mark having a length shorter than the optical system resolution of the reproducing apparatus (a recording mark generated when information is recorded on a pre-pit or a recording type optical information medium).
- An optical information recording medium that is stable against changes in the external environment according to usage conditions, and an adhesive transparent resin layer used in the production of the optical information recording medium
- an optical information recording medium reproducing method and an optical information recording medium reproducing apparatus for reproducing the optical information recording medium for reproducing the optical information recording medium.
- the first invention group constitutes an optical information recording medium in which a signal having a mark length shorter than the optical system resolution limit of the reproducing apparatus can be reproduced by reproducing light irradiated at the time of reproducing.
- the “adhesive sheet” in the present specification is a layer including an adhesive transparent resin layer, and may be a single layer or a plurality of layers. Moreover, there is no restriction
- the “information recording layer” in the present specification is an information recording layer having a function of reproducing a mark having a length shorter than the optical system resolution limit of the reproducing apparatus, and is a metal film and / or a metal oxide film. It may be a single layer or a plurality of layers.
- optical information recording medium in this specification refers to a medium on which information can be optically recorded / reproduced, and mainly corresponds to a read-only type, a write-once type, or a rewritable type disc-like medium. Specific examples include CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-R, DVD-RW, DVD-RAM, Blu-ray Disc, and the like. Absent.
- the optical information recording medium which can reproduce
- the (meth) acrylic acid ester copolymer preferably contains methyl (meth) acrylate as a monomer component (Invention 2).
- the (meth) acrylic acid ester copolymer preferably contains a nitrogen atom-containing copolymerizable monomer as a monomer component (Invention 3).
- the second invention group provides an optical information recording medium in which the pressure-sensitive adhesive sheet for optical information recording medium (Invention 1 to 4) is provided on an information recording layer (Invention 5).
- substrate are laminated
- the third invention group provides an optical information recording medium reproduction method (Invention 7), characterized by using the optical information recording medium (Inventions 5 and 6).
- the fourth invention group provides an optical information recording medium driving device using the optical information recording medium (Inventions 5 and 6) (Invention 8).
- an optical information recording medium that can reproduce a mark shorter than the optical system resolution of the reproducing apparatus and is stable against changes in the external environment.
- FIG. 1 is a cross-sectional view of an optical information recording medium according to an embodiment of the present invention. It is a figure which shows an example of the manufacturing method of the optical information recording medium based on the embodiment.
- FIG. 1 is a cross-sectional view of an optical information recording medium pressure-sensitive adhesive sheet according to an embodiment of the present invention.
- the pressure-sensitive adhesive sheet for optical information recording medium according to the present embodiment is for protecting the information recording layer in the optical information recording medium, but is not limited thereto.
- An adhesive sheet 1 for an optical information recording medium includes a transparent resin layer 11 and a protective sheet (protective layer) 12 laminated on one surface (upper surface in FIG. 1) of the transparent resin layer 11. And a release sheet 13 laminated on the other surface (the lower surface in FIG. 1) of the transparent resin layer 11.
- the protective sheet 12 serves as a protective layer in the optical information recording medium, and the release sheet 13 is peeled off and removed when the optical information recording medium pressure-sensitive adhesive sheet 1 is used.
- the transparent resin layer 11 in the present embodiment is used to bond the information recording layer 3 (see FIG. 2) formed on the substrate 2 of the optical information recording medium and the protective sheet 12. Therefore, the transparent resin layer 11 is preferably a layer made of an adhesive.
- This transparent resin layer 11 is mainly composed of a (meth) acrylic acid ester copolymer that does not contain an acidic group, a storage elastic modulus at 23 ° C. of 1.5 ⁇ 10 5 Pa or less, and a gel fraction. It is necessary to be 68% by mass or more.
- the transparent resin layer 11 It is possible to prevent the occurrence of cracks in the information recording layer 3 adjacent to. Therefore, according to the pressure-sensitive adhesive sheet 1 for optical information recording medium having the transparent resin layer 11, an optical information recording medium that is stable against changes in the external environment can be manufactured.
- the transparent resin layer 11 requires that a (meth) acrylic acid ester copolymer containing no acidic group is a main component.
- a (meth) acrylic acid ester copolymer is a polymer containing a (meth) acrylic acid ester monomer as a constituent component, and is excellent as an optical application.
- the (meth) acrylic acid ester copolymer does not contain an acidic group. When the acidic group is contained, the adhesive force of the transparent resin layer 11 to the information recording layer 3 is improved, but the information recording layer 3 is easily corroded, and as a result, a reading error occurs.
- the storage elastic modulus at 23 ° C. of the transparent resin layer 11 needs to be 1.5 ⁇ 10 5 Pa or less, and preferably 1.3 ⁇ 10 5 Pa or less. If the storage elastic modulus exceeds 1.5 ⁇ 10 5 Pa, cracks may occur in the information recording layer 3 adjacent to the transparent resin layer 11 when a sudden temperature / humidity change occurs in the environment of the obtained optical information recording medium. Occurs, and the function as an optical information recording medium is lost.
- the lower limit of the storage elastic modulus at 23 ° C. of the transparent resin layer 11 is not particularly limited from the viewpoint of preventing cracks, but is preferably 1.0 ⁇ 10 3 Pa or more, particularly 1.0 ⁇ 10 4 Pa or more. It is preferable that When the storage elastic modulus is 1.0 ⁇ 10 3 Pa or more, the retainability of the protective sheet 12 laminated on the transparent resin layer 11 is improved.
- the gel fraction of the transparent resin layer 11 needs to be 68% by mass or more, and preferably 74% by mass or more. When the gel fraction of the transparent resin layer 11 is less than 68% by mass, the reproduction sensitivity of the obtained optical information recording medium is lowered.
- the upper limit of the gel fraction of the transparent resin layer 11 is not particularly limited from the viewpoint of preventing cracks, but is preferably 95% by mass or less, and particularly preferably 85% by mass or less. If the gel fraction of the transparent resin layer 11 exceeds 95% by mass, the transparent resin layer 11 is not tacky, and the adhesive force to the information recording layer 3 cannot be obtained.
- This gel fraction can be adjusted by the degree of crosslinking when producing the resin component constituting the transparent resin layer 11 mainly composed of a (meth) acrylic acid ester copolymer.
- the measuring method of the said storage elastic modulus and gel fraction is as showing in the Example mentioned later.
- the (meth) acrylic acid alkyl ester monomer constituting the (meth) acrylic acid ester copolymer will be described.
- the (meth) acrylic acid alkyl ester monomer is a (meth) acrylic acid alkyl ester having an alkyl ester moiety having 1 to 20 carbon atoms, preferably having an alkyl ester moiety having 1 to 12 carbon atoms (meta ) Acrylic acid alkyl ester.
- Examples include dodecyl, myristyl (meth) acrylate, palmityl (meth) acrylate, and stearyl (meth) acrylate. These can be used alone or in combination of two or more.
- the ratio of the above (meth) acrylic acid alkyl ester monomer to all monomers constituting the (meth) acrylic acid ester copolymer is preferably 70 to 97% by mass, particularly 75 to 95% by mass. It is preferable that When the ratio of the (meth) acrylic acid alkyl ester is within this range, the transparent resin layer 11 that is pressure-bonded to the information recording layer 3 follows the unevenness of the information recording layer 3 well, so that the reliability of information recording and reproduction is improved. In addition, the content of the nitrogen atom-containing copolymerizable monomer described later can be ensured.
- the (meth) acrylic acid ester copolymer particularly preferably contains methyl (meth) acrylate as a monomer component, and more preferably contains methyl acrylate as a monomer component.
- methyl (meth) acrylate as a monomer component, the adhesive strength of the transparent resin layer 11 obtained to the metal / metal oxide can be improved.
- methyl (meth) acrylate methyl acrylate or methyl methacrylate can be used alone, or methyl acrylate and methyl methacrylate can be used in combination.
- the ratio of methyl (meth) acrylate to all monomers constituting the (meth) acrylate copolymer is preferably 1 to 40% by mass, and particularly preferably 5 to 35% by mass. .
- the ratio of methyl (meth) acrylate is in this range, the adhesive force of the transparent resin layer 11 to the information recording layer 3 becomes good.
- the (meth) acrylic acid ester copolymer preferably contains a nitrogen atom-containing copolymerizable monomer as a constituent component.
- the nitrogen atom-containing copolymerizable monomer is a polar component and can improve the adhesion of the resulting (meth) acrylic acid ester copolymer to the metal / metal oxide.
- nitrogen atom-containing copolymerizable monomer examples include acrylamide, methacrylamide, N-methylacrylamide, N-methylmethacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N-tert-butylacrylamide, N- Vinylpyrrolidone, N, N-dimethylacrylamide, N, N-ethylacrylamide, N, N-dimethylaminopropylacrylamide, N-isopropylacrylamide, N-phenylacrylamide, dimethylaminopropylacrylamide, N-vinylcaprolactam, acryloylmorpholine, ( (Meth) acrylic acid monomethylaminoethyl, (meth) acrylic acid monoethylaminoethyl, (meth) acrylic acid monomethylaminopropyl, (meth) acrylic acid monoethyl Minopuropiru, can be used in combination with (meth) dimethylaminoethyl acrylate,
- the ratio of nitrogen atom-containing copolymerizable monomer to all monomers constituting the (meth) acrylic acid ester copolymer is preferably 0.1 to 30% by mass, particularly 0.3 to 30%.
- the content is preferably mass%, more preferably 0.4 to 25 mass%.
- the ratio of the nitrogen atom-containing copolymerizable monomer is within this range, the adhesive force of the transparent resin layer 11 to the information recording layer 3 becomes better. If the ratio of the nitrogen atom-containing copolymerizable monomer exceeds 30% by mass, the embedding property (following property) of the transparent resin layer 11 with respect to the information recording layer 3 may be deteriorated.
- the (meth) acrylic acid ester copolymer preferably includes both the above-mentioned methyl (meth) acrylate and a nitrogen atom-containing copolymerizable monomer as monomer components.
- the (meth) acrylic acid ester copolymer preferably has a crosslinkable functional group in the molecule.
- the crosslinkable functional group include a carboxyl group, a hydroxy group, a glycidyl group, and a carbon-carbon unsaturated bond.
- the hydroxy group, the glycidyl group, and the carbon-carbon unsaturated bond are included. Is preferred. Hydroxy groups and glycidyl groups react with a crosslinking agent to crosslink, and carbon-carbon unsaturated bonds crosslink by their mutual addition reaction.
- a method of irradiating active energy rays such as an electron beam or ultraviolet rays is performed.
- active energy rays such as an electron beam or ultraviolet rays
- a carboxyl group is also a crosslinkable functional group, since a carboxyl group is an acidic group and causes the information recording layer 3 to corrode, it is preferable not to include a monomer having a carboxyl group.
- a hydroxy group or glycidyl group into a (meth) acrylic acid ester copolymer it can be copolymerized with a (meth) acrylic acid ester and a (meth) acrylic acid ester having a hydroxy group or a glycidyl group in the molecule. It is sufficient to polymerize with a monomer.
- the monomer having a hydroxy group in the molecule include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and (meth) acrylic acid.
- Examples include (meth) acrylic acid hydroxyalkyl esters such as 2-hydroxybutyl, (meth) acrylic acid 3-hydroxybutyl, and (meth) acrylic acid 4-hydroxybutyl.
- Examples of the monomer having a glycidyl group in the molecule include And glycidyl (meth) acrylate. These monomers can be used alone or in combination of two or more.
- a functional group having a carbon-carbon unsaturated bond into the (meth) acrylic acid ester copolymer for example, a carbon-carbon unsaturated bond and a functional group of the (meth) acrylic acid ester copolymer in the molecule.
- a method of reacting a compound having a functional group which reacts with (hereinafter referred to as “unsaturated bond-containing compound”) and a (meth) acrylic acid ester copolymer a compound having a functional group which reacts with (hereinafter referred to as “unsaturated bond-containing compound”) and a (meth) acrylic acid ester copolymer.
- the functional group of the unsaturated bond-containing compound and the functional group of the (meth) acrylic acid ester copolymer may be appropriately selected, and a hydroxy group, an isocyanate group, a glycidyl group, or the like can be used.
- an isocyanate group may be used as the functional group of the unsaturated bond-containing compound.
- unsaturated bond-containing compounds include compounds having an isocyanate group such as methacryloyloxyethyl isocyanate and allyl isocyanate, compounds having a glycidyl group such as glycidyl (meth) acrylate, and the like. Two or more kinds can be used in combination.
- the ratio of the monomer having a crosslinkable functional group in the molecule to all monomers constituting the (meth) acrylic acid ester copolymer is preferably 0.1 to 10% by mass, particularly 0 It is preferably 2 to 5% by mass.
- the ratio of the monomer having a crosslinkable functional group in the molecule is within this range, the (meth) acrylic acid ester copolymer can be well crosslinked, and the gel fraction of the transparent resin layer can be increased.
- the above-mentioned preferable value can be obtained.
- the crosslinkable functional group is a carbon-carbon unsaturated bond
- the monomer having a crosslinkable functional group is a monomer in which a carbon-carbon unsaturated bond is introduced by reacting with an unsaturated bond-containing compound. I mean.
- the (meth) acrylic acid ester copolymer may contain a monomer other than the above monomers as a constituent, if desired.
- monomers include (meth) acrylic acid alkoxyalkyl esters such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate, vinyl acetate, and styrene.
- the (meth) acrylic acid ester copolymer described above can be produced by any known polymerization method such as solution polymerization or bulk polymerization using a mixture of the above monomers as a raw material.
- the polymerization initiator used in the polymerization include an azo initiator and a peroxide initiator.
- azo initiator examples include 2,2′-azobisisobutyronitrile, 2,2′-azobis-2-methylbutyronitrile, 2,2′-azobis (2-methylpropionic acid) dimethyl, 4,4'-azobis-4-cyanovaleric acid, azobisisovaleronitrile, 2,2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis [2- (5-methyl-2-imidazoline) -2-yl) propane] dihydrochloride, 2,2'-azobis (2-methylpropionamidine) disulfate, 2,2'-azobis (N, N'-dimethyleneisobutylamidine) dihydrochloride, etc.
- peroxide initiator examples include dibenzoyl peroxide and tert-butyl permaleate.
- the amount of the polymerization initiator used is not particularly limited, but is usually 0.01 to 2 parts by mass with respect to 100 parts by mass of the monomer component.
- the weight average molecular weight of the (meth) acrylic acid ester copolymer is preferably about 200,000 to 1,800,000, more preferably 500,000 to 1,500,000.
- the (meth) acrylic acid ester copolymer is preferably cross-linked by a cross-linking agent.
- a cross-linking agent By crosslinking the (meth) acrylic acid ester copolymer, the strength and storage stability of the transparent resin layer 11 can be improved.
- the gel fraction of the transparent resin layer 11 is controllable by adjusting the crosslinking degree of a (meth) acrylic acid ester copolymer.
- polyisocyanate compound examples include tolylene diisocyanate or a hydride thereof, an adduct of tolylene diisocyanate and trimethylolpropane, triphenylmethane triisocyanate, methylene bis-di-phenyl isocyanate or a hydride thereof, Hexamethylene diisocyanate, adduct of hexamethylene diisocyanate and trimethylolpropane, xylylene diisocyanate, adduct of xylene diisocyanate and trimethylolpropane, 4,4'-dicyclohexylmethane diisocyanate, or As these polymers, those having two or more isocyanate groups in the molecule can be used.
- crosslinkable functional group is a carbon-carbon unsaturated bond
- it is appropriately selected from compounds that generate radicals by light or heat according to the type of the information recording layer 3 of the optical information recording medium.
- the amount of the crosslinking agent used is not particularly limited, but is usually 0.001 to 20 parts by mass with respect to 100 parts by mass of the (meth) acrylic acid ester copolymer.
- the pressure-sensitive adhesive constituting the transparent resin layer 11 includes an antioxidant, a tackifier resin (petroleum resin, terpene resin, rosin resin, coumarone indene resin, Phenol resin, etc.), ultraviolet absorbers, light stabilizers, softeners, rust inhibitors, silane coupling agents, fillers, and the like.
- a tackifier resin petroleum resin, terpene resin, rosin resin, coumarone indene resin, Phenol resin, etc.
- ultraviolet absorbers ultraviolet absorbers
- light stabilizers softeners
- rust inhibitors silane coupling agents
- fillers and the like.
- antioxidant any one selected from conventionally known hindered phenol antioxidants, amine antioxidants, sulfur antioxidants, phosphorus antioxidants, quinone antioxidants, and the like is appropriately selected.
- a hindered phenolic antioxidant is preferably used. By adding these antioxidants, corrosion of the information recording layer 3 can be more effectively suppressed.
- the antioxidant include monocyclic phenolic antioxidants such as 2,6-di-tert-butyl-p-cresol, butylhydroxyanisole and stearyl ⁇ - (3,5-di-tert-butyl- 4-Hydroxyphenyl) propionate or the like as a bicyclic phenolic antioxidant as 4,4′-butylidenebis (3-methyl-6-tert-butylphenol) and 3,6-dioxaoctamethylenebis [3- (3 -Tert-butyl-4-hydroxy5-methylphenyl) propionate] and the like as 1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane as a tricyclic phenolic antioxidant Tetrakis [methylene-3- (3 ′, 5′-di-tert-butyl-) as a tetracyclic phenolic antioxidant '- hydroxyphenyl) propionate] methane, etc. may be
- the amount of the antioxidant used is not particularly limited, but is usually 0.005 to 10% by mass, preferably 0.01 to 5% by mass, more preferably in the pressure-sensitive adhesive constituting the transparent resin layer 11. 0.1-3 mass%.
- the amount of the antioxidant used is 0.005% by mass or more, the effect of inhibiting corrosion of the information recording layer 3 is exhibited.
- the content exceeds 10% by mass, the effect is not improved for the amount, and it may be economically disadvantageous.
- the pressure-sensitive adhesive constituting the transparent resin layer 11 preferably has a total content of residual solvent and residual monomer of 100 mass ppm or less, particularly 50 mass ppm or less, more preferably 20 mass ppm or less. As described above, since the residual amounts of the solvent and the monomer are small, the corrosion of the information recording layer 3 can be more effectively suppressed, and the corrosion of the protective sheet 12 and the optical information recording medium on the substrate 2 can be suppressed. it can.
- the thickness of the transparent resin layer 11 is appropriately determined according to the depth of the concavo-convex pattern (prepits, lands, or grooves) formed on the substrate 2, but is usually about 5 to 60 ⁇ m, preferably 10 ⁇ 30 ⁇ m.
- the protective sheet 12 in this embodiment is for protecting the information recording layer 3 in the optical information recording medium, and constitutes the light receiving surface of the optical information recording medium.
- the material of the protective sheet 12 needs to have a sufficient light transmittance with respect to the wavelength range of the laser beam used for the optical information recording medium, and is generally visible in the wavelength range of 380 to 780 nm.
- a light transmissive film that transmits light is used.
- a light transmissive film for example, a film made of a transparent resin such as an acrylic resin, a polyolefin resin, a polycarbonate resin, or a norbornene resin can be used.
- the linear expansion coefficient of the protective sheet 12 is preferably substantially the same as the linear expansion coefficient of the substrate 2 so that the optical information recording medium does not warp at high temperatures. Therefore, when the board
- a hard coat layer may be provided on the surface of the light transmissive film opposite to the transparent resin layer 11. By providing this hard coat layer, for example, even if the optical head of the drive comes into contact with the surface of the protective sheet 12, it is difficult to be damaged.
- the protective sheet 12 is preferably one having a surface that is as flat as possible and is less likely to cause birefringence.
- the light condensing degree of the condensed laser light is deteriorated. Further, if there is uneven thickness, it causes a reduction in the degree of condensing of the laser light, so it is preferable that the uneven thickness is as small as possible.
- the thickness of the protective sheet 12 is determined according to the type of the optical information recording medium, the thickness of the substrate 2, and the like, but is usually about 50 to 100 ⁇ m, preferably about 60 to 90 ⁇ m.
- release sheet 13 conventionally known ones can be used.
- resin films such as polyethylene terephthalate and polypropylene, and resin films made of silicone release agents, long-chain alkyl release agents, alkyd resin types, for example.
- a release sheet subjected to a release treatment with a release agent or the like can be used.
- the release sheet 13 preferably has a surface roughness (Ra) on the side subjected to the release treatment (side in contact with the transparent resin layer 11) of 0.1 ⁇ m or less.
- the thickness of the release sheet 13 is usually about 10 to 200 ⁇ m, preferably about 20 to 100 ⁇ m.
- the adhesive strength of the pressure-sensitive adhesive sheet for optical information recording media is preferably 8.0 N / 25 mm or more, particularly preferably 10 N / 25 mm or more, as will be described later.
- the adhesive force is 8.0 N / 25 mm or more, the adhesive force between the transparent resin layer 11 and the information recording layer 3 becomes sufficient, and peeling between the two hardly occurs.
- the measuring method of adhesive force is shown in the Example mentioned later.
- the form of the pressure-sensitive adhesive sheet 1 for an optical information recording medium according to the present embodiment is not particularly limited, and may be a single unit or a plurality of layers. Moreover, there is no restriction
- the production method of the optical information recording medium pressure-sensitive adhesive sheet 1 according to the present embodiment is not particularly limited.
- the material constituting the transparent resin layer 11 and, if desired, a solvent for example, ethyl acetate, toluene, 2-butanone, etc.
- a coating agent containing a kiss roll coater, a reverse roll coater, a knife coater, a roll knife coater, a die coater, a spin coater and the like is applied onto the protective sheet 12 and dried, and the transparent resin layer 11 is dried.
- the protective sheet 12 is laminated on the surface of the transparent resin layer 11.
- the transparent resin layer 11 is preferably dried by heating at 70 ° C. or higher, preferably 80 to 150 ° C. for about 10 seconds to 10 minutes.
- the thus obtained pressure-sensitive adhesive sheet 1 for optical information recording medium can be preferably applied to an optical information recording medium, particularly an optical information recording medium having a wavelength of light used for recording / reproduction of 395 to 432 nm.
- the pressure-sensitive adhesive sheet 1 for manufacturing an optical information recording medium (a laminate of the protective sheet 12 and the transparent resin layer 11) excluding the release sheet 13 has a light transmittance of 85% or more at a wavelength of 395 to 432 nm. preferable. If the light transmittance is 85% or more, the transmission of the laser light incident on the information recording layer of the optical information recording medium and the reflected light from the information recording layer is good.
- the light transmittance is more preferably 90% or more.
- FIG. 2 is a cross-sectional view of an optical information recording medium according to an embodiment of the present invention
- FIGS. 3A to 3D are views showing an example of a method for manufacturing an optical information recording medium according to the embodiment. It is.
- the optical information recording medium D1 includes a protective sheet (protective layer) 12 from the incident surface side (upper surface side in FIG. 2) on which reproduction light is incident during reproduction,
- the transparent resin layer 11, the information recording layer 3, and the substrate 2 are laminated.
- the materials for the protective sheet 12 and the transparent resin layer 11 are as described above.
- the substrate 2 those usually used for optical information recording media can be used, which are generally made of polycarbonate and can be molded by a molding method such as injection molding.
- the information recording layer 3 has a layer adapted to a read-only optical information recording medium or a recordable optical information recording medium.
- a layer suitable for a reproduction-only optical information recording medium a two-layer structure of a zinc oxide film and a Ta film sputtering layer in order from the reproduction light incident surface side is preferable from the viewpoint of practicality including reproduction durability.
- a recording type optical information recording medium such as a rewritable type or a recordable type
- a multilayer structure including a phase change film composed of a zinc oxide film and GeSbTe is preferable.
- the structure of the information recording layer 3 in the present embodiment is not limited to the above, and may be a layer structure that exhibits super-resolution characteristics.
- the substrate 2 is made of polycarbonate having a thickness of 1.1 mm, for example.
- the material and thickness of the substrate 2 are not limited to this, and may be a predetermined strength that can be used as a substrate on which irregularities such as prepits or grooves are provided on the surface.
- the substrate 2 may be made of, for example, a polyolefin resin or a metal. Further, the substrate 2 may have a multilayer structure.
- a substrate 2 having a concavo-convex pattern such as a prepit or a groove is manufactured.
- An information recording layer 3 is formed on the uneven pattern of the substrate 2 as shown in FIG.
- the information recording layer 3 is formed by depositing Ta (7 nm) and a zinc oxide film (60 nm) on the uneven pattern of the substrate 2 by sputtering.
- the release sheet 13 of the pressure-sensitive adhesive sheet 1 for optical information recording medium is peeled off to expose the transparent resin layer 11, and as shown in FIG.
- the layer 11 is pressure-bonded to the surface of the information recording layer 3 on the substrate 2.
- the transparent resin layer 11 can be used even when it is placed under high temperature and / or high humidity, or even when a sudden temperature change and / or humidity change occurs. It is possible to prevent the occurrence of cracks in the information recording layer 3 adjacent to the surface of the information recording layer 3, and thus it is stable against changes in the external environment. Furthermore, when the (meth) acrylic acid ester copolymer constituting the transparent resin layer 11 does not contain an acidic group, corrosion of the information recording layer 3 can be suppressed. Therefore, according to the pressure-sensitive adhesive sheet 1 for optical information recording medium, it is possible to obtain a highly reliable optical information recording medium D1 that does not hinder the information recording / reproducing function. This optical information recording medium D1 is suitable as a super-resolution medium.
- the optical information recording medium D1 is a single-sided single-layer type, but may be a single-sided two-layer type or may be a multilayer.
- the adhesive which comprises the transparent resin layer 11 which comprises the adhesive sheet 1 for optical information recording media was previously formed in layers and used as the adhesive sheet 1 for optical information recording media
- the transparent resin layer 11 may be liquefied by a method such as melting or dissolving in a solvent, and an optical information recording medium pressure-sensitive adhesive sheet may be formed on the information recording layer 3 by a spin coating method or the like.
- the adhesive sheet for optical information recording media for forming the protective layer of an optical information recording medium for example, it has the transparent resin layer 11 and does not have the protective sheet 12.
- An adhesive sheet for an optical information recording medium is produced, and the transparent resin layer 11 of the adhesive sheet for an optical information recording medium may be used for bonding two substrates provided with an information recording layer together.
- optical information recording medium playback method In the optical information recording medium reproducing method according to the present embodiment, the optical information recording medium is used as a super-resolution medium.
- the focusing means can be simplified compared to the conventional super-resolution medium, and the reproduction laser power is higher than that of the conventional super-resolution medium. Even if it is set to a value lower than the power, sufficient reproduction is possible, so that the power consumption of the reproduction apparatus can be reduced.
- optical information recording medium driving device In the optical information recording medium driving apparatus according to the present embodiment, the optical information recording medium is used as a super-resolution medium.
- the focusing means can be simplified compared with the conventional super-resolution medium having a relatively low reflectance, and the reproduction laser power is the same as the conventional one. Even if it is set to a value lower than the laser power for the super-resolution medium, sufficient reproduction is possible, so that the power consumption of the reproduction apparatus can be reduced.
- a focus error occurs, if there is a means to increase the reproduction laser power and retry, it is easy to focus while keeping the gain adjustment of the light receiving element as usual, so the cost increases The reliability of the focus can be improved while minimizing.
- the release sheet 13 in the optical information recording medium pressure-sensitive adhesive sheet 1 may be omitted.
- Example 1 A method for producing the pressure-sensitive adhesive sheet for optical information recording medium of Example 1 will be described below. First, 68.5 parts by mass of n-butyl acrylate as monomer components, 30 parts by mass of methyl acrylate, 1 part by mass of 2-hydroxyethyl acrylate, and 0.5 parts by mass of acrylamide, and azobisiso 0.2 parts by mass of butyronitrile was added to 200 parts by mass of ethyl acetate, and the mixture was stirred at 60 ° C. for 17 hours to obtain an acrylate copolymer solution. In addition, the weight average molecular weight of the obtained acrylic acid ester copolymer was 600,000.
- xylene diisocyanate trifunctional adduct (TD-75, manufactured by Soken Chemical Co., Ltd.) as a cross-linking agent was 0.6.
- a mass part was added and diluted with 2-butanone to a solution with a concentration of 25% by mass to obtain an adhesive solution.
- This pressure-sensitive adhesive solution was applied to a release-treated surface of a release sheet (SP-PET 381031, polyethylene terephthalate film released by a silicone resin-based release agent) using a knife coater, and dried at 90 ° C. for 1 minute. A transparent resin layer having a thickness of 25 ⁇ m was formed. Next, a polycarbonate film (manufactured by Teijin Limited, Pure Ace C110-75, thickness: 75 ⁇ m) as a protective sheet was laminated on the transparent resin layer. Thus, an adhesive sheet for optical information recording media of Example 1 having a thickness of 138 ⁇ m was obtained.
- Example 2 A method for producing the pressure-sensitive adhesive sheet for optical information recording medium of Example 2 will be described below.
- Example 1 is the same as Example 1 except that the acrylic acid ester copolymer obtained by adding 78.5 parts by mass of n-butyl acrylate and 20 parts by mass of methyl acrylate was used.
- the adhesive sheet for optical information recording media of Example 2 having a thickness of 138 ⁇ m was prepared in the same manner as described above.
- the weight average molecular weight of the obtained acrylic acid ester copolymer was 650,000.
- Example 3 A method for producing the pressure-sensitive adhesive sheet for optical information recording medium of Example 3 will be described below.
- a xylene diisocyanate-based cross-linking agent was used using an acrylate copolymer obtained by adding 78.5 parts by mass of n-butyl acrylate and 20 parts by mass of methyl acrylate.
- An adhesive sheet for optical information recording medium of Example 3 having a thickness of 138 ⁇ m was prepared in the same manner as in Example 1 except that the amount of addition was changed to 1.2 parts by mass.
- the weight average molecular weight of the obtained acrylic acid ester copolymer was 650,000.
- Example 4 A method for producing the pressure-sensitive adhesive sheet for optical information recording medium of Example 4 will be described below.
- the optical information recording medium of Example 4 having a thickness of 138 ⁇ m was prepared in the same manner as in Example 1 except that the addition amount of the xylene diisocyanate-based crosslinking agent in Example 1 was changed to 0.3 parts by mass.
- a pressure-sensitive adhesive sheet for production was produced.
- the weight average molecular weight of the obtained acrylic acid ester copolymer was 600,000.
- Comparative Example 1 A method for producing the pressure-sensitive adhesive sheet for optical information recording medium of Comparative Example 1 will be described below.
- the optical information recording medium of Comparative Example 1 having a thickness of 138 ⁇ m was prepared in the same manner as in Example 1 except that the addition amount of the xylene diisocyanate-based crosslinking agent was changed to 1.2 parts by mass in Example 1.
- a pressure-sensitive adhesive sheet was prepared.
- the weight average molecular weight of the obtained acrylic acid ester copolymer was 550,000.
- Example 2 A method for producing the pressure-sensitive adhesive sheet for optical information recording medium of Comparative Example 2 will be described below.
- a xylene diisocyanate-based cross-linking agent was used using an acrylate copolymer obtained by adding 78.5 parts by mass of n-butyl acrylate and 20 parts by mass of methyl acrylate.
- the same operation as in Example 1 was performed except that the amount of addition was changed to 0.3 parts by mass, and a pressure-sensitive adhesive sheet for optical information recording medium of Comparative Example 2 having a thickness of 138 ⁇ m was produced.
- the weight average molecular weight of the obtained acrylic acid ester copolymer was 600,000.
- Example 3 A method for producing the pressure-sensitive adhesive sheet for optical information recording medium of Comparative Example 3 will be described below.
- Example 1 except that 77 parts by mass of n-butyl acrylate, 20 parts by mass of ethyl acrylate, and 3 parts by mass of acrylic acid ester copolymer were used as monomer components.
- the same operation as in Example 1 was performed to produce an optical information recording medium pressure-sensitive adhesive sheet of Comparative Example 3 having a thickness of 138 ⁇ m.
- the weight average molecular weight of the obtained acrylic acid ester copolymer was 540,000.
- the storage elastic modulus (Pa) at 23 ° C. of the formed transparent resin layer was measured at a measurement frequency of 1 Hz using a viscoelasticity measuring device (manufactured by Rheometrics, DYNAMIC ANALYZER RDA II). The results are shown in Table 1.
- the initial transmittance Ta1 for light having a wavelength of 405 nm was measured for the obtained sample. Specifically, using a UV-visible spectrophotometer (manufactured by Shimadzu Corporation, UV-3100PC), 405 nm light was irradiated from the protective sheet side of the sample, and the transmittance was measured.
- a UV-visible spectrophotometer manufactured by Shimadzu Corporation, UV-3100PC
- the initial transmittance Ta2 for light having a wavelength of 405 nm was measured for the obtained sample. Specifically, using a UV-visible spectrophotometer (manufactured by Shimadzu Corporation, UV-3100PC), 405 nm light was irradiated from the protective sheet side of the sample, and the transmittance was measured.
- a UV-visible spectrophotometer manufactured by Shimadzu Corporation, UV-3100PC
- Test Example 4 (Crack resistance test) ⁇ Crack test by heat> Sputtered film surface of a polycarbonate plate (thickness: 1.2 mm) on which a Ta film (7 nm) and a zinc oxide film (60 nm) were formed in this order by sputtering the pressure-sensitive adhesive sheet for optical information recording media produced in Examples and Comparative Examples The sample was pasted on a transparent resin layer and used as a sample.
- the obtained sample was placed in an environment at a temperature of 80 ° C. for 70 hours, and immediately placed in an environment at 23 ° C. and a relative humidity of 65% for 24 hours. Thereafter, the zinc oxide film was observed using a digital microscope (manufactured by Keyence Corporation, UV-3100PC) to observe the occurrence of cracks and evaluated according to the following criteria. The results are shown in Table 1. ⁇ : No change with respect to the initial state (no cracking) ⁇ : Cracks are partially generated ⁇ : Cracks are generated entirely
- the obtained sample was placed in an environment of a temperature of 60 ° C. and a relative humidity of 85% for 70 hours, and immediately placed in an environment of 23 ° C. and a relative humidity of 65% for 24 hours. Thereafter, the zinc oxide film was observed using a digital microscope (manufactured by Keyence Corporation, UV-3100PC) to observe the occurrence of cracks and evaluated according to the following criteria. The results are shown in Table 1. ⁇ : No change with respect to the initial state (no cracking) ⁇ : Cracks are partially generated ⁇ : Cracks are generated entirely
- the obtained sample was allowed to stand for 24 hours under conditions of 23 ° C. and 50% relative humidity, and then, using a universal tensile tester (Orientec, Tensilon), a peeling speed of 300 mm / min and a peeling angle of 180 °. Then, the pressure-sensitive adhesive sheet for optical information recording medium was peeled from the zinc oxide film, and the adhesive force (N / 25 mm) was measured. The results are shown in Table 1.
- Test Example 6 (Signal characteristic evaluation) A zinc oxide film (60 nm) and a Ta film (7 nm) are formed as an information recording layer 3 by sputtering on a polycarbonate substrate provided with a 1-7 modulation random pattern having a minimum pit length of 94 nm, and a cover layer is formed thereon. As described above, the pressure-sensitive adhesive sheets for optical information recording media produced in Examples 1, 2, 4 and Comparative Example 2 were attached so as to be adjacent to the information recording layer 3, and this was used as a sample disk. Further, the laminate of the polycarbonate substrate and the cover layer prepared in Reference Example 1 was used as a comparative sample disk.
- the above sample disk is made up of a semiconductor laser capable of emitting laser light having a wavelength of 405 nm and N.I. A. (Aperture ratio) Reproduced by a disk evaluation machine having an optical system of 0.85 (DDU-1000, manufactured by Pulstec Corp.), and a reproduction signal obtained for each reproduction laser power is decoded by PRML (12221).
- the bER (bit error rate) for each reproduction laser power was calculated for each sample disk. Further, the reflectance at the reproduction wavelength of each sample disk was obtained during the reproduction.
- the bERs of the sample disks using Examples 1, 2, and 4, Comparative Example 2, and Reference Example 1 at a reproduction laser power of 0.7 mW were 1.4 ⁇ 10 ⁇ 4 and 2.0 ⁇ , respectively.
- the bER at the reproduction laser power of 0.5 mW is 8.4 ⁇ 10 ⁇ 4 , respectively.
- the bER at the reproduction laser power of 0.4 mW is 2.9 ⁇ , respectively.
- the reflectance of the sample disks using Examples 1, 2, and 4, Comparative Example 2, and Reference Example 1 is about 4% at the reproduction laser power of 0.5 mW only in Reference Example 1, and the reflection of other sample disks. The value was lower than the rate (5.0 to 5.4%).
- the reflectivity of the sample disks using Examples 1, 2, 4 and Comparative Example 2 increased as the reproduction laser power increased. That is, in comparison with Reference Example 1 which is a general optical disc cover layer, Examples 1, 2, 4 and Comparative Example 2 are equivalent in terms of reproduction sensitivity and have a high reflectance. .
- Examples 1, 2, 4 and Comparative Example 2 in which the reflectance is increased if the reproduction sensitivity is equivalent are the general optical disks. It can be said that it is superior to the reference example 1, which is a cover layer material, in terms of a super-resolution optical information recording medium manufacturing margin.
- Example 3 and Comparative Example 1 are compared with a sample disk using Reference Example 1 in terms of reproduction sensitivity and reflectance. Compared to the disk, it was confirmed that Example 3 and Comparative Example 1 were improved by about 0.2 mW, and the reflectance was improved similarly to the other samples, and it was confirmed that it increased as the reproduction laser power increased. It was done.
- Table 1 shows the results evaluated based on the following criteria.
- ⁇ Reproduction sensitivity> A Better than Reference Example 1 (can reproduce signal from lower reproduction laser power)
- ⁇ Equivalent to Reference Example 1 (signal reproduction is possible with the same level of reproduction laser power)
- ⁇ worse than Reference Example 1 (can reproduce signal from higher reproduction laser power)
- the present invention is useful for the production of a super-resolution medium having excellent durability and high reliability even under sudden environmental changes, or as the super-resolution medium.
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- Optical Record Carriers And Manufacture Thereof (AREA)
Abstract
Description
〔光情報記録媒体製造シート〕
図1は本発明の一実施形態に係る光情報記録媒体用粘着シートの断面図である。本実施形態に係る光情報記録媒体用粘着シートは、光情報記録媒体における情報記録層を保護するためのものであるが、これに限定されない。
図2は、本発明の一実施形態に係る光情報記録媒体の断面図であり、図3(a)~(d)は、同実施形態に係る光情報記録媒体の製造方法の一例を示す図である。
本実施形態に係る光情報記録媒体再生方法では、超解像媒体として、上記光情報記録媒体を用いる。
本実施形態に係る光情報記録媒体駆動装置では、超解像媒体として、上記光情報記録媒体を用いる。
実施例1の光情報記録媒体用粘着シートの作製方法を、以下に説明する。
まず、単量体成分としてアクリル酸n-ブチル68.5質量部、アクリル酸メチル30質量部、アクリル酸2-ヒドロキシエチル1質量部、及びアクリルアミド0.5質量部と、開始剤としてアゾビスイソブチロニトリル0.2質量部とを酢酸エチル200質量部中に添加し、60℃で17時間攪拌することにより、アクリル酸エステル共重合体溶液を得た。なお、得られたアクリル酸エステル共重合体の重量平均分子量は60万であった。
実施例2の光情報記録媒体用粘着シートの作製方法を、以下に説明する。
実施例1において、アクリル酸n-ブチルの添加量を78.5質量部、アクリル酸メチルの添加量を20質量部として得られたアクリル酸エステル共重合体を用いたこと以外は、実施例1と同様の操作を行い、厚さ138μmの実施例2の光情報記録媒体用粘着シートを作製した。なお、得られたアクリル酸エステル共重合体の重量平均分子量は65万であった。
実施例3の光情報記録媒体用粘着シートの作製方法を、以下に説明する。
実施例1において、アクリル酸n-ブチルの添加量を78.5質量部、アクリル酸メチルの添加量を20質量部として得られたアクリル酸エステル共重合体を用い、キシレンジイソシアナート系架橋剤の添加量を1.2質量部に変更したこと以外は、実施例1と同様の操作を行い、厚さ138μmの実施例3の光情報記録媒体用粘着シートを作製した。なお、得られたアクリル酸エステル共重合体の重量平均分子量は65万であった。
実施例4の光情報記録媒体用粘着シートの作製方法を、以下に説明する。
実施例1において、キシレンジイソシアナート系架橋剤の添加量を0.3質量部に変更したこと以外は、実施例1と同様の操作を行い、厚さ138μmの実施例4の光情報記録媒体製造用粘着シートを作製した。なお、得られたアクリル酸エステル共重合体の重量平均分子量は60万であった。
比較例1の光情報記録媒体用粘着シートの作製方法を、以下に説明する。
実施例1において、キシレンジイソシアナート系架橋剤の添加量を1.2質量部に変更したこと以外は、実施例1と同様の操作を行い、厚さ138μmの比較例1の光情報記録媒体用粘着シートを作製した。なお、得られたアクリル酸エステル共重合体の重量平均分子量は55万であった。
比較例2の光情報記録媒体用粘着シートの作製方法を、以下に説明する。
実施例1において、アクリル酸n-ブチルの添加量を78.5質量部、アクリル酸メチルの添加量を20質量部として得られたアクリル酸エステル共重合体を用い、キシレンジイソシアナート系架橋剤の添加量を0.3質量部に変更したこと以外は、実施例1と同様の操作を行い、厚さ138μmの比較例2の光情報記録媒体用粘着シートを作製した。なお、得られたアクリル酸エステル共重合体の重量平均分子量は60万であった。
比較例3の光情報記録媒体用粘着シートの作製方法を、以下に説明する。
実施例1において、単量体成分としてアクリル酸n-ブチル77質量部、アクリル酸エチル20質量部、及びアクリル酸3質量部として得られたアクリル酸エステル共重合体を用いたこと以外は、実施例1と同様の操作を行い、厚さ138μmの比較例3の光情報記録媒体用粘着シートを作製した。なお、得られたアクリル酸エステル共重合体の重量平均分子量は54万であった。
一般的な光情報記録媒体用透光層(光ディスク用カバー層)の例として、紫外線硬化型樹脂(三菱レイヨン社製,MP107)を、後述の試験例6に記載するポリカーボネート基板上に成膜した情報記録層にスピンコートにより塗布した後、紫外線照射し硬化させることで、カバー層を形成した。
実施例および比較例で作製した光情報記録媒体用粘着シートの透明樹脂層を重ね合わせ、厚さ2.5mmの透明樹脂層を形成した。
実施例および比較例で調製した粘着剤溶液をナイフコーターによって重剥離シート(リンテック社製,SP-PET381031,ポリエチレンテレフタレートフィルムをシリコーン樹脂系剥離剤で剥離処理したもの)の剥離処理面に塗布し、90℃で1分間乾燥して厚さ25μmの透明樹脂層を形成した。次いで、その透明樹脂層に、軽剥離シート(リンテック社製,SP-PET38GS,ポリエチレンテレフタレートフィルムをシリコーン樹脂系剥離剤で剥離処理したもの)をラミネートし、これをサンプルとした。
ゲル分率(%)=(乾燥・調湿後の未溶解成分質量/抽出前の粘着剤質量)×100
<熱による耐腐食性試験>
実施例および比較例で製造した光情報記録媒体用粘着シートを、酸化亜鉛膜をスパッタしたガラス板に透明樹脂層を介して貼付し、これをサンプルとした。なお、このときの光情報記録媒体用粘着シートの状態を初期状態とする。
Y1(%)=[(Ta1-Tb1)/Ta1]×100
実施例および比較例で製造した光情報記録媒体用粘着シートを、酸化亜鉛膜をスパッタしたガラス板に透明樹脂層を介して貼付し、これをサンプルとした。なお、このときの光情報記録媒体用粘着シートの状態を初期状態とする。
Y2(%)=[(Ta2-Tb2)/Ta2]×100
<熱による耐クラック試験>
実施例および比較例で製造した光情報記録媒体用粘着シートを、Ta膜(7nm)と酸化亜鉛膜(60nm)を順にスパッタリングにより成膜したポリカーボネート板(厚さ:1.2mm)のスパッタ膜面上に透明樹脂層を介して貼付し、これをサンプルとした。
○:初期状態に対し変化なし(クラックの発生なし)
△:部分的にクラックが発生している
×:全体にクラックが発生している
実施例および比較例で製造した光情報記録媒体用粘着シートを、Ta膜(7nm)と酸化亜鉛膜(60nm)を順にスパッタリングにより成膜したポリカーボネート板(厚さ:1.2mm)のスパッタ膜面上に透明樹脂層を介して貼付し、これをサンプルとした。
○:初期状態に対し変化なし(クラックの発生なし)
△:部分的にクラックが発生している
×:全体にクラックが発生している
ポリカーボネート板(厚さ:1.1mm)上に、Ta膜(7nm)および酸化亜鉛膜(60nm)を順にスパッタリングにより成膜した。実施例および比較例で製造した光情報記録媒体用粘着シートを幅25mm、長さ100mmに切断した後、ラミネーターを用いて剥離シートを剥離しながら、透明樹脂層を上記酸化亜鉛膜上に貼付し、これをサンプルとした。
最短ピット長94nmとなる1-7変調ランダムパターンが設けられたポリカーボネート製基板に、スパッタリングにより酸化亜鉛膜(60nm)およびTa膜(7nm)を情報記録層3として成膜し、その上にカバー層として、実施例1,2,4および比較例2で製造した光情報記録媒体用粘着シートを情報記録層3に隣接するように貼付し、これをサンプルディスクとした。また、上記参考例1で作製したポリカーボネート基板とカバー層との積層体を、比較用サンプルディスクとした。
<再生感度>
◎:参考例1より良い(より低い再生レーザパワーから信号再生可能)
○:参考例1と同等(同程度の再生レーザパワーから信号再生可能)
×:参考例1より悪い(より高い再生レーザパワーから信号再生可能)
<反射率>
○:参考例1より高い
△:参考例1と同等
×:参考例1より低い
11…透明樹脂層
12…保護シート(保護層)
13…剥離シート
2…基板
3…情報記録層
D1…光情報記録媒体
Claims (8)
- 再生時に照射される再生用の光によって、再生装置の有する光学系解像限界より短いマーク長の信号が再生され得る光情報記録媒体を構成する粘着シートであって、
前記光情報記録媒体の情報記録層上に設けられる粘着性の透明樹脂層を有し、
前記透明樹脂層は、
酸性基を含有しない(メタ)アクリル酸エステル共重合体が主成分であり、
23℃における貯蔵弾性率が1.5×105Pa以下であり、かつ
ゲル分率が68質量%以上である
ことを特徴とする光情報記録媒体用粘着シート。 - 前記(メタ)アクリル酸エステル共重合体は、(メタ)アクリル酸メチルを単量体成分として含むことを特徴とする請求項1に記載の光情報記録媒体用粘着シート。
- 前記(メタ)アクリル酸エステル共重合体は、窒素原子含有共重合性単量体を単量体成分として含むこと特徴とする請求項1または2に記載の光情報記録媒体用粘着シート。
- 保護層をさらに含むことを特徴とする請求項1~3のいずれかに記載の光情報記録媒体用粘着シート。
- 請求項1~4のいずれかに記載の光情報記録媒体用粘着シートが、情報記録層上に設けられてなる光情報記録媒体。
- 再生時に再生用の光が入射する入射面側から、保護層と、前記透明樹脂層と、前記情報記録層と、基板とが積層されてなることを特徴とする請求項5に記載の光情報記録媒体。
- 請求項5または6に記載の光情報記録媒体を用いることを特徴とする光情報記録媒体再生方法。
- 請求項5または6に記載の光情報記録媒体を用いることを特徴とする光情報記録媒体駆動装置。
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CN2010800435982A CN102893333A (zh) | 2009-10-01 | 2010-09-27 | 光信息记录媒体用粘着片、光信息记录媒体、光信息记录媒体再生方法以及装置 |
US13/497,866 US8691357B2 (en) | 2009-10-01 | 2010-09-27 | Pressure-sensitive adhesive sheet for optical data recording medium, optical data recording medium, and method and device for reproducing data from optical data recording medium |
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CN (1) | CN102893333A (ja) |
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JP3832659B2 (ja) | 2003-06-06 | 2006-10-11 | シャープ株式会社 | 光情報記録媒体、それを用いた記録方法、再生方法、光情報記録装置、および光情報再生装置 |
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- 2010-09-27 CN CN2010800435982A patent/CN102893333A/zh active Pending
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CN102893333A (zh) | 2013-01-23 |
JP2011076692A (ja) | 2011-04-14 |
US20120246666A1 (en) | 2012-09-27 |
JP5089667B2 (ja) | 2012-12-05 |
US8691357B2 (en) | 2014-04-08 |
TW201120169A (en) | 2011-06-16 |
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