JP4570604B2 - Optical recording medium manufacturing sheet, optical recording medium, and manufacturing method thereof - Google Patents

Description

  The present invention relates to an optical recording medium manufacturing sheet capable of forming an optical recording medium by forming a protective layer in the optical recording medium, a manufacturing method thereof, and an optical recording medium manufactured using such an optical recording medium manufacturing sheet. And a manufacturing method thereof.

A next-generation large-capacity optical recording medium such as a Blu-ray Disc employs a structure in which a protective layer for protecting the recording layer is provided on the recording layer. As a method for forming this protective layer, a method of attaching an optical film excellent in film thickness accuracy and optical characteristics to a recording layer via an adhesive or an adhesive (Patent Document 1), or a photocurable adhesive film is recorded. There is a method of transferring to a layer (Patent Document 2).
Japanese Patent No. 3338660 JP 2002-25110 A

  However, the method described in Patent Document 1 requires a film that satisfies special optical performance, and such an optical film is expensive. In addition, the number of steps until the optical film is bonded to the recording layer is large, and it is difficult to reduce the cost.

  On the other hand, also in the method described in Patent Document 2, when a hard coat layer or the like is formed on the surface of the photocurable adhesive film after the photocurable adhesive film is transferred to the recording layer, first, photocurable adhesive film is used. It is necessary to irradiate the agent film with light, cure the photocurable adhesive film to form a protective layer, then apply a hard coat agent or the like to the protective layer, and dry and cure the coating film, There was a problem that the number of processes was large.

  The present invention has been made in view of such a situation, and can form a protective layer of an optical recording medium easily and inexpensively, and can form other layers on the protective layer with a small number of steps. An object of the present invention is to provide a sheet for manufacturing an optical recording medium and a method for manufacturing the same, an optical recording medium manufactured using the sheet for manufacturing an optical recording medium, and a method for manufacturing the optical recording medium.

  In order to achieve the above object, first, the present invention is an optical recording medium manufacturing sheet provided with an energy curable layer, wherein the first surface of the energy curable layer is adhered to a SUS304 steel plate or a polycarbonate plate. Provided is a sheet for manufacturing an optical recording medium, wherein the force is less than 10 mN / 25 mm, and the adhesive force of the second surface of the energy curable layer to the SUS304 steel plate or polycarbonate plate is 100 mN / 25 mm or more ( Claim 1).

  Secondly, the present invention is an optical recording medium manufacturing sheet provided with an energy curable layer, wherein the first surface of the energy curable layer has an adhesive force of less than 10 mN / 25 mm to a SUS304 steel plate or a polycarbonate plate. The second surface of the energy curable layer is attached to either a SUS304 steel plate or a polycarbonate plate to completely cure the energy curable layer, and the second surface is applied to the SUS304 steel plate or the polycarbonate plate. An adhesive sheet having an adhesive strength of 100 mN / 25 mm or more is provided (claim 2).

  The “optical recording medium” in this specification refers to a medium on which information can be optically recorded / reproduced, and is mainly a read-only, write once or rewritable disc-like medium (eg, CD, CD-ROM, CD-R, CD-RW, DVD, DVD-ROM, DVD-R, DVD-RW, DVD-RAM, LD, Blu-ray Disc, HD DVD, MO, etc .; Including)), but is not necessarily limited thereto.

  Further, the “adhesive strength” in the present invention refers to the current adhesive strength (before the main curing) of the energy curable layer, and the “adhesive strength” in the present invention is the energy curable layer attached to the adherend. Thereafter, it refers to the adhesive force of the energy curable layer to the adherend when the energy curable layer is fully cured. These “adhesive strength” and “adhesive strength” are represented by values measured according to test examples described later.

  According to the above inventions (Inventions 1 and 2), since an expensive film substrate is not used as the protective layer, the protective layer of the optical recording medium can be formed at a low cost. In addition, since the second surface of the energy curable layer has a predetermined adhesive force or adhesive force and does not require a separate adhesive layer, a protective layer can be easily formed, and the protective layer and the adhesive layer There is no problem of delamination between layers and scattering of reflected light between layers. On the other hand, the adhesive force of the first surface of the energy curable layer is relatively low, and it is possible to apply and form another layer on the surface with a uniform film thickness. Therefore, before main-curing the energy-curable layer, a coating film of another energy-curable layer is formed on the first surface of the energy-curable layer, and energy is applied to the laminate, whereby both layers Can be cured at one time (main curing), and another energy cured layer can be formed on the protective layer with a small number of steps.

  In the said invention (invention 1 and 2), it is preferable that the said energy curable layer consists of a single layer (invention 3). According to this invention (Invention 3), it is possible to easily form the energy curable layer with a small number of steps.

  In the said invention (Invention 1-3), it is preferable that the said energy curable layer is a layer hardened | cured by irradiation of an energy ray, or was hardened or semi-hardened (Invention 4). According to the energy ray irradiation, it is easy to control the degree of curing of the energy curable layer.

  In the above invention (Inventions 1 to 4), the energy curable layer is obtained by curing or semi-curing a material mainly composed of an energy curable component having a polymerizable double bond by application of energy, The disappearance ratio of the double bond of the energy curable component on the first surface of the energy curable layer is 60% or more, and more than the disappearance ratio of the double bond of the energy curable component on the second surface. More than 15% is preferable (Claim 5).

  In the above inventions (Inventions 1 to 5), the energy curable layer is preferably a material in which an energy curable monomer and / or oligomer as a main component is cured or semi-cured (Invention 6).

  In the said invention (invention 6), it is preferable that content of the energy curable monomer in the said material is 50 mass% or less, and content of energy curable oligomer is 50 mass% or more (invention 7). . According to this invention (invention 7), the degree of cure in the thickness direction of the energy curable layer can be easily changed, and the adhesive force on the first surface and the adhesive force on the second surface are the above inventions (invention 1). It becomes easy to change like 2).

  In the above invention (Inventions 1 to 7), the energy curable layer preferably forms a protective layer of an optical recording medium.

  Thirdly, in the present invention, a coating agent containing a material having an energy curable component as a main component is applied to a substrate, and the obtained coating film is opposite to the first surface in contact with the substrate. When the second surface of the coating film is placed in the presence of oxygen and energy is applied to the coating film, the adhesive force of the first surface of the coating film to the SUS304 steel plate or the polycarbonate plate is less than 10 mN / 25 mm. For producing an optical recording medium, wherein the coating film is cured or semi-cured to form an energy curable layer so that the adhesive strength to the SUS304 steel plate or the polycarbonate plate on the second surface is 100 mN / 25 mm or more A method for producing a sheet is provided (claim 8).

  In this specification, “semi-cured” refers to a state between uncured and completely cured, and “cured” refers to all of the cured state rather than the uncured state. Including curing. “Complete curing” refers to a state in which curing does not substantially proceed even when energy is further applied.

  According to the method of the present invention (invention 8), the first surface of the coating film is brought into contact with the substrate, and the second surface is placed in the presence of oxygen, so that the degree of curing of the energy curable component is changed to the first. It can be large on the first surface and small on the second surface, and as described above, an energy curable layer having different adhesive strengths depending on the surface can be obtained.

  In the said invention (invention 8), you may affix another base material on the said 2nd surface of the formed energy hardening layer (invention 9). Thereby, it is possible to protect the 2nd surface with comparatively large adhesive force of an energy hardening layer.

  In the above inventions (inventions 8 and 9), the energy curable component has a polymerizable double bond, and by application of the energy, two energy curable components on the first surface of the coating film are formed. It is preferable to eliminate the double bond by 60% or more and 15% or more more than the disappearance ratio of the double bond of the energy curable component on the second surface (claim 10).

  In the said invention (invention 8-10), it is preferable that the said material has an energy curable monomer and / or an oligomer as a main component (invention 11).

  In the said invention (invention 11), it is preferable that content of the energy curable monomer in the said material shall be 50 mass% or less, and content of energy curable oligomer shall be 50 mass% or more (invention 12). .

  In the said invention (invention 8-12), it is preferable to use an energy ray as energy applied for formation of the said energy curable layer (invention 13). If energy rays are used, it is easy to control the degree of curing of the energy curable layer.

  4thly this invention makes it the state which exposed the said 2nd surface of the said energy curable layer in the said sheet | seat for optical recording medium manufacture (Claims 1-7), and said 2nd of the said energy curable layer. A protective layer is formed by applying a surface to a recording layer of an optical recording medium, and applying energy to the energy curable layer to cure the energy curable layer. A method is provided (claim 14).

  In the said invention (invention 14), before applying energy with respect to the said energy curable layer, the coating film of the other layer of energy curable is formed on the said 1st surface of the said energy curable layer. (Claim 15). According to this invention (invention 15), the energy curable layer and the other energy curable layer can be cured at once (main curing), and the other energy cured layer can be applied to the protective layer with a small number of steps. Can be formed. In addition, the first surface of the energy curable layer that forms the coating film of the other energy curable layer has a relatively low adhesive force and is cured to some extent. Can be applied and formed.

  In the said invention (invention 15), it is preferable that the said other layer of energy hardening is a hard-coat layer (invention 16).

  In the said invention (invention 14-16), it is preferable to use an energy ray as energy applied for formation of the said protective layer (invention 17).

The fifth aspect of the present invention is an optical recording medium manufactured using the optical recording medium manufacturing sheet (Claim 3 ) , wherein the energy curable layer of the optical recording medium manufacturing sheet is the optical recording medium. An optical recording medium is provided which is directly laminated on a recording layer of the medium and serves as a protective layer of the optical recording medium (claim 18).

  According to the present invention, a protective layer for an optical recording medium can be formed inexpensively and easily, and in the manufacturing process of the optical recording medium, another layer such as a hard coat layer is added to the protective layer with a small number of steps. It can also be formed.

Hereinafter, embodiments of the present invention will be described.
[Sheet for optical recording medium production]
FIG. 1 is a cross-sectional view of an optical recording medium manufacturing sheet according to an embodiment of the present invention. The optical recording medium manufacturing sheet 1 according to the present embodiment includes an energy curable layer 11 and base materials 12 and 12 ′ laminated on both surfaces of the energy curable layer 11. However, the base materials 12 and 12 ′ are peeled off when the optical recording medium manufacturing sheet 1 is used.

  The energy curable layer 11 is a layer that can constitute a protective layer for protecting the recording layer of the optical recording medium. The adhesive force of one surface (first surface; for example, the surface on the base material 12 side) of the energy curable layer 11 to the SUS304 steel plate or the polycarbonate plate is less than 10 mN / 25 mm.

  Further, the adhesive strength of the other surface (second surface; for example, the surface on the substrate 12 ′ side) of the energy curable layer 11 is 100 mN / 25 mm or more, preferably 300 to 1,000,000 mN with respect to the SUS304 steel plate. / 25 mm or 100 mN / 25 mm or more, preferably 500 to 1,000,000 mN / 25 mm with respect to the polycarbonate plate. On the other hand, when the adhesive strength after complete curing is defined instead of the current adhesive strength, the second surface of the energy curable layer 11 is attached to the SUS304 steel plate and the energy curable layer 11 is completely cured. The adhesive strength of the second surface to the SUS304 steel plate is 100 mN / 25 mm or more, preferably 500 to 1,000,000 mN / 25 mm, or the second surface of the energy curable layer 11 is pasted on a polycarbonate plate to cure the energy. The adhesive force of the second surface to the polycarbonate plate after the conductive layer 11 is completely cured is 100 mN / 25 mm or more, preferably 1,000 to 1,000,000 mN / 25 mm. It is particularly preferable that the adhesive force after complete curing of the second surface of the energy curable layer 11 is within the above range for both the SUS304 steel plate and the polycarbonate plate.

In addition, the said adhesive force and adhesive force are represented by the value measured according to the test example mentioned later. As shown in this test example, in this specification, 1000 mJ / cm ² of ultraviolet irradiation is performed as energy applied for complete curing of the energy curable layer 11. After the ultraviolet irradiation, the curing reaction does not substantially proceed even when the ultraviolet rays are further irradiated. Moreover, the adhesive force of the said range of the 1st surface of the energy curable layer 11 means that hardening of the 1st surface has progressed to such an extent that it does not have a substantial adhesive force.

  On the other hand, the second surface of the energy curable layer 11 is intended to be stuck on the recording layer of the optical recording medium. The surface of the recording layer of the optical recording medium has a metal portion that actually becomes a recording portion and a polycarbonate portion that is located at the peripheral edge of the metal portion. Therefore, when the adhesive force of the second surface or the adhesive force after complete curing is within the above range with respect to the SUS304 steel plate or the polycarbonate plate, the object as the optical recording medium manufacturing sheet 1 can be achieved.

  In the energy curable layer 11, the first surface has a higher degree of curing than the second surface, and the first surface has another layer (for example, a hard coat layer described later) on the first surface. ) Is cured to the extent that it can be formed as it is (including the concept of semi-curing and complete curing), and the second surface is cured to such an extent that it has adhesive strength that can be applied to the recording layer of the optical recording medium (half-curing). Including concept). Thereby, the energy curable layer 11 as a whole has a strength that allows punching and pasting.

  Since the adhesive force of the first surface of the energy curable layer 11 is within the above range, the coating film of the other layer is uniformly formed on the first surface before the energy curable layer 11 is fully cured. It is possible to form with. In addition, when the adhesive force of the second surface of the energy curable layer 11 or the adhesive force after complete curing is in the above range, the energy curable layer 11 can be attached to the recording layer of the optical recording medium, and The energy curable layer 11 and the recording layer are firmly bonded, and an optical recording medium in which delamination hardly occurs is obtained.

  Further, since the energy curable layer 11 is in such a cured state, the energy curable layer 11 has sufficient hardness, and when the optical recording medium manufacturing sheet 1 is punched into the shape of the optical recording medium. In addition, there is no possibility that the energy curable layer 11 protrudes or deforms, and the yield can be maintained high.

  The energy curable layer 11 is a layer that is cured by application of energy, or is cured or semi-cured. Examples of the energy to be applied include energy rays or heat. Preferably, energy rays whose degree of curing is easily controlled by an irradiation amount or the like are used. Therefore, the energy curable layer 11 is preferably a layer that is cured by irradiation of energy rays, or a cured or semi-cured layer.

  The energy curable layer 11 is preferably composed of a single layer (a layer made of a single material). As a result, it is possible to easily form with a smaller number of steps than to form a plurality of layers (see a method for forming the energy curable layer 11 described later).

  The energy curable layer 11 is preferably a material obtained by curing or semi-curing a material mainly composed of an energy curable component having a polymerizable double bond (hereinafter referred to as “energy curable material”). In this case, the disappearance ratio of the double bond of the energy curable component on the first surface of the energy curable layer 11 is 60% or more, particularly 65 to 90%, and two of the energy curable component on the second surface. It is preferably 15% or more, particularly 20% or more, more than the disappearance ratio of the heavy bond. In addition, it is preferable that the loss | disappearance ratio of the double bond of the energy curable component in the 2nd surface of the energy curable layer 11 is 10 to 75%, especially 10 to 50%.

  After the rate of disappearance of the double bond of the energy curable component is in such a range, the adhesive force on the first surface and the second surface of the energy curable layer 11 and the substrate are completely cured by applying energy. It becomes easy to enter the adhesive force within the above range. Further, the energy curable layer 11 has a certain degree of hardness, and prevents the energy curable layer 11 from protruding or deforming when the optical recording medium manufacturing sheet 1 is punched into the shape of the optical recording medium. can do.

  The energy curable material preferably contains an energy curable monomer and / or oligomer as a main component. By using energy curable materials based on energy curable monomers and / or oligomers, the use of solvents can be significantly reduced or eliminated altogether. As a result, a solvent drying step is not required and productivity is improved, and it is also effective for environmental measures. Furthermore, the omission of the drying step eliminates the risk of foaming that tends to occur during drying. Here, an oligomer shall mean a thing with a mass average molecular weight of 500-10,000, and a preferable mass average molecular weight is 1,000-10,000.

  As the energy curable monomer and / or oligomer, an ester of polyhydric alcohol and (meth) acrylic acid having a polymerizable double bond is preferably used. Examples of such energy curable monomers and / or oligomers include monofunctional acrylates such as cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, p-cumylphenoxyethyl (meth) acrylate, urethane (meth) ) Acrylate, bisphenol A di (meth) acrylate, ethylene oxide modified bisphenol A di (meth) acrylate, propylene oxide modified bisphenol A di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, Pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6- Polyfunctional acrylic esters such as xanthandiol di (meth) acrylate, polyethylene glycol di (meth) acrylate, dimethylol tricyclodecane di (meth) acrylate, polyester oligo (meth) acrylate, polyurethane oligo (meth) acrylate, etc. Is mentioned. These energy curable monomers and / or oligomers may be used alone or in combination of two or more.

  The content of the energy curable monomer in the energy curable material is preferably 50% by mass or less, and the content of the energy curable oligomer is preferably 50% by mass or more. In particular, the content of the energy curable monomer is preferably 10 to 50% by mass, and the content of the energy curable oligomer is preferably 50 to 90% by mass.

  When the content of the energy curable monomer and the energy curable oligomer in the energy curable material is in the above range, the degree of curing in the thickness direction of the energy curable layer 11 can be easily changed, and the adhesive force on the first surface can be changed. It becomes easy to change the adhesive force on the second surface as described above.

  The energy curable component may contain an energy curable polymer. As the energy curable polymer, it is preferable to use a (meth) acrylic acid ester (co) polymer having an energy curable group introduced in the side chain.

  The mass average molecular weight of the energy curable polymer is preferably greater than 10,000. The upper limit is not particularly limited, but is preferably 2,500,000 or less.

  When the energy curable component contains an energy curable polymer, the content is preferably 0.5 to 60% by mass in the energy curable material. When the energy curable material contains the energy curable polymer in this range, the energy curable material can be handled as a solution having a relatively constant viscosity with respect to fluctuations in various external factors such as temperature. .

  When ultraviolet rays are used as the energy for curing the energy curable layer 11, the energy curable material preferably contains a photopolymerization initiator. By using this photopolymerization initiator, the polymerization curing time and the light beam can be increased. Irradiation amount can be reduced.

  Specific examples of the photopolymerization initiator include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, methyl benzoin benzoate, benzoin dimethyl ketal, 2,4 -Diethylthioxanthone, 1-hydroxycyclohexyl phenyl ketone, benzyldiphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, β-chloranthraquinone, (2,4,6-trimethyl) Benzyldiphenyl) phosphine oxide, 2-benzothiazole-N, N-diethyldithiocarbamate, oligo {2-hydroxy-2-methyl-1 [4- (1-propenyl) phenyl] propanone}, and 2,2-dimethoxy-1,2-and the like. These may be used alone or in combination of two or more. Among these, it is preferable to use a photopolymerization initiator having the same absorption region as the wavelength of ultraviolet rays irradiated to the energy curable layer 11.

  The photopolymerization initiator is added to 100 parts by mass of energy curable monomer and / or oligomer (when energy curable polymer is blended, the total amount of energy curable monomer and / or oligomer and energy curable polymer is 100 parts by mass). It is preferably used in an amount in the range of 0.1 to 10 parts by mass, particularly 0.5 to 6 parts by mass.

  On the other hand, when heat is used as the energy for curing the energy curable layer 11, the energy curable material preferably contains a thermal polymerization initiator. Specific examples of the thermal polymerization initiator include peroxides such as benzoyl peroxide and azo compounds such as 2,2-azobisisobutyronitrile.

  Thermal polymerization initiator is added to 100 parts by mass of energy curable monomer and / or oligomer (when energy curable polymer is blended, the total amount of energy curable monomer and / or oligomer and energy curable polymer is 100 parts by mass). It is preferably used in an amount in the range of 0.1 to 10 parts by mass, particularly 0.5 to 6 parts by mass.

  The energy curable material may contain an energy non-curable polymer. As the energy non-curable polymer, for example, it is preferable to use a thermoplastic resin such as an acrylic resin, polycarbonate, polyester, polyurethane, etc. that is inexpensive and excellent in transparency.

  The content of the energy non-curable polymer is preferably 0.5 to 60% by mass in the energy curable material. When the energy curable material contains the energy non-curable polymer in this range, it becomes possible to maintain a relatively constant viscosity against fluctuations in various external factors such as temperature, and handling of the energy curable material is facilitated. It becomes easy.

  Moreover, when the energy curable material contains a compound having a functional group in its composition, it may contain a crosslinking agent. Examples of the crosslinking agent include isocyanate compounds, epoxy compounds, amine compounds, melamine compounds, aziridine compounds, hydrazine compounds, aldehyde compounds, oxazoline compounds, metal alkoxide compounds, metal chelate compounds, metal salts, ammonium salts, and reactive phenol resins. Etc. can be used.

  The content of the crosslinking agent is preferably 0.01 to 30 parts by mass, particularly preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the total amount of the compound having a polymerizable functional group. .

  The energy curable material may contain an inorganic filler. Examples of the inorganic filler include silica, alumina, titanium oxide, zinc oxide, calcium oxide, antimony oxide, tin oxide, germanium oxide, and cerium oxide.

  The average particle size of the inorganic filler is usually 0.001 to 200 μm. Moreover, when using an inorganic filler, it is preferable that the content is 0.1-40 mass% in energy curable material.

  Furthermore, the energy curable material may contain an adhesion improver in order to improve the adhesive force of the energy curable layer 11 to the recording layer of the optical recording medium. As the adhesion improver, for example, a monomer having a carboxyl group such as acrylic acid, methacrylic acid, itaconic acid, 2-acryloyloxyethyl succinic acid is preferably used.

  The content of the adhesion improver is preferably 0.001 to 10% by mass, and particularly preferably 0.005 to 1% by mass in the energy curable material.

  Further, the energy curable material may contain various additives. Examples of the additive include a leveling agent for improving the surface smoothness of the energy curable layer 11, an antioxidant, an ultraviolet absorber, a dye, a plasticizer, a thickener, a silane coupling agent, and an antistatic agent. An agent, a tackifier, etc. can be used. The compounding quantity of these additives is not specifically limited, It determines suitably in the range of about 0-30 mass% in energy curable material.

  The thickness of the energy curable layer 11 is appropriately determined in consideration of the purpose of use of the energy curable layer 11, and is generally preferably 0.5 to 600 μm, particularly preferably 3 to 150 μm. Furthermore, it is preferable that it is 15-120 micrometers.

The film thickness accuracy in 1 m ² of the energy curable layer 11 is preferably ± 10% or less of the target film thickness, particularly preferably ± 5% or less. If it exceeds ± 10%, the focal point of the laser may be deviated, and the signal may not be read normally. Note that the film thickness accuracy is sufficiently maintained even after the entire energy curable layer 11 is completely cured.

  The retardation after complete curing of the energy curable layer 11 is preferably 20 nm or less, and particularly preferably 15 nm or less. If the retardation of the energy curable layer 11 exceeds 20 nm, the signal characteristics of the obtained optical recording medium may be deteriorated.

  Regarding the transparency after complete curing of the energy curable layer 11, the 405 nm spectral transmittance is preferably 80% or more, and particularly preferably 85% or more. If the 405 nm spectral transmittance is less than 80%, the signal characteristics of the obtained optical recording medium may be deteriorated.

  As the base materials 12 and 12 ', conventionally known materials can be used. For example, resin films such as polyethylene terephthalate and polypropylene, and these resin films can be used as silicone release agents, long-chain alkyl release agents, alkyd resins. A release film subjected to a release treatment with a system release agent or the like can be used. The substrate 12 on the side in contact with the first surface of the energy curable layer 11 is not particularly required to be peeled off because the adhesive strength of the first surface is low, but the second layer of the energy curable layer 11 is not required. The substrate 12 ′ on the side in contact with the surface is preferably subjected to a peeling treatment since the adhesive strength of the second surface is relatively high.

  When using a release film that has been subjected to a release treatment as both the base materials 12 and 12 ′, the base material 12 ′ that is peeled first from the energy curable layer 11 is used as a light release type release film and then peeled off later. It is preferable that the base material 12 is a heavy release type release film.

  In addition, when ultraviolet rays may be irradiated as energy through the base material 12 or the base material 12 ', the base material 12 or the base material 12' needs to be made of a transparent material.

  The base materials 12 and 12 ′ have a surface roughness (Ra) on the side in contact with the energy curable layer 11 of 0.1 μm or less, particularly 0.05 μm or less in order to impart smoothness to the energy curable layer 11. Preferably there is. If the surface roughness (Ra) of the substrates 12 and 12 'exceeds 0.1 μm, the surface roughness of the energy curable layer 11 increases, and the signal characteristics of the resulting optical recording medium may be degraded. The thickness of the base materials 12 and 12 ′ is usually about 10 to 200 μm, preferably about 20 to 100 μm.

[Method for producing sheet for producing optical recording medium]
Next, a method for manufacturing the optical recording medium manufacturing sheet 1 according to the embodiment will be described. FIG. 2 is a diagram showing a method for manufacturing the optical recording medium manufacturing sheet 1.

  In order to manufacture the sheet 1 for manufacturing an optical recording medium, first, as shown in FIGS. 2A to 2B, an application agent containing an energy curable material is applied on the surface of the substrate 12, A coating film 11p is obtained. The coating agent containing the energy curable material may contain only the energy curable material, or may further contain a solvent if desired.

  The solvent is not particularly limited as long as it dissolves oligomers and monomers such as ethyl acetate and acetone used for viscosity adjustment of the coating agent or its additive. When a solvent is added to the coating agent, the coating film 11p is formed and then appropriately dried to remove the solvent from the coating film 11p.

  As the coating method of the coating agent, it is preferable to use a coating machine such as a knife coater, a roll knife coater, a kiss roll coater, a reverse roll coater, or a die coater that can form a coating film having a uniform film thickness. . According to these coating methods, the energy curable layer 11 with high film thickness accuracy can be formed.

  Next, as shown in FIG. 2C, energy is applied to the obtained coating film 11p, and the adhesive force and coating of the surface (first surface) of the coating film 11p in contact with the substrate 12 are applied. The energy curable layer 11 is formed by curing or semi-curing the energy curable material so that the adhesive force of the exposed surface (second surface) of the film 11p has the value described above.

  At this time, the exposed surface (second surface) of the coating film 11p is assumed to be in the presence of oxygen. In the presence of oxygen, the curing reaction due to the energy application of the energy curable component is inhibited, so that the curing of the energy curable component is difficult to proceed. Therefore, the first surface of the coating film 11p that is in contact with the base material 12 and does not come into contact with oxygen is cured and the adhesive force is reduced, while the second surface of the exposed coating film 11p is cured. It is difficult to maintain the adhesive strength relatively high, and the energy curable layer 11 having different adhesive strength depending on the surface as described above can be obtained.

As a method for applying energy, there is irradiation of energy rays or heating, but irradiation with energy rays that can easily control the degree of curing is preferably performed. As energy rays, ultraviolet rays, electron beams, etc. are usually used. The irradiation amount of the energy ray is not particularly limited as long as the energy curable material can be cured or semi-cured so that the first surface and the second surface of the energy curable layer 11 exhibit the above adhesive force. in the case of, preferably 1~150mJ / cm ² in quantity, in particular 5 to 100 mJ / cm ² is preferred.

  Thus, while providing a difference in the oxygen concentration in each surface of the energy curable layer 11 and controlling the amount of energy to be applied, both surfaces of the single composition layer can be brought into a desired cured state.

  Finally, if desired, as shown in FIG. 2D, a base material 12 'is laminated on the exposed surface (second surface) of the energy curable layer 11. By laminating the base material 12 ′, the second surface having a relatively high adhesive force of the energy curable layer 11 can be protected.

[Method of manufacturing optical recording medium]
Next, an example of a method for manufacturing an optical recording medium D (single-sided single-layer type) using the optical recording medium manufacturing sheet 1 will be described. 3A to 3F are diagrams showing an example of a method for manufacturing an optical recording medium D using the optical recording medium manufacturing sheet 1 described above.

  In addition, the optical recording medium manufacturing sheet 1 is previously punched and formed into the shape of the optical recording medium D. The punching process may be performed by a conventional method, for example, using a punching device or the like. Since the energy curable layer 11 of the optical recording medium manufacturing sheet 1 is cured or semi-cured, there is no possibility that the energy curable layer 11 protrudes or deforms in this punching process, and the yield is maintained high. be able to.

  First, as shown in FIG. 3A, an optical recording medium substrate 2 having an uneven pattern composed of grooves and lands is manufactured. The optical recording medium substrate 2 is usually made of polycarbonate and can be formed by a molding method such as injection molding.

  A recording layer 3 is formed on the concave-convex pattern of the optical recording medium substrate 2 as shown in FIG. The recording layer 3 is usually composed of a film made of an inorganic material or a laminate of the film, for example, a laminate composed of a reflective film, a dielectric film, a phase change film, and a dielectric film in order from the bottom. The These films can be formed by means such as sputtering.

  Next, as shown in FIG. 3C, the base material 12 ′ is peeled and removed from the second surface of the energy curable layer 11 of the optical recording medium manufacturing sheet 1 to remove the second of the energy curable layer 11. The surface is exposed, and the energy curable layer 11 is pressure-bonded to the surface of the recording layer 3 on the optical recording medium substrate 2. As an apparatus that can be used for such pressure bonding, for example, an optical disk laminating apparatus disclosed in Japanese Patent Application Laid-Open No. 2003-151181 can be cited.

  At this time, since the second surface of the energy curable layer 11 has a predetermined adhesive force, the energy curable layer 11 can be attached to the recording layer 3.

  As shown in FIG. 3D, when the base 12 is peeled and removed from the energy curable layer 11 to expose the first surface of the energy curable layer 11, as shown in FIG. An energy curable hard coat agent is applied onto the first surface of the energy curable layer 11 to obtain a coating film 4p.

  At this time, the first surface of the energy curable layer 11 is cured to a relatively high degree and does not have adhesiveness that hinders the operation of applying the hard coating agent. The coating film 4p can be formed with a uniform film thickness.

  Finally, as shown in FIG. 3 (f), energy is applied to the energy curable layer 11 and the coating film 4p, and the entire energy curable layer 11 is fully cured to form a protective layer, and the coating film 4p. Is hardened as a hard coat layer 4. Thereby, the optical recording medium D is obtained. Here, “main curing” is performed in order to stabilize the adhesive state of the energy curable layer 11 after the optical recording medium manufacturing sheet 1 is attached to the optical recording medium substrate 2. If a stable performance is obtained as D, the main curing may not be in a completely cured state.

As a method of applying energy for the main curing, there is irradiation of energy rays or heating, but energy rays that are not affected by heat or the like are preferably irradiated with a short process time. As energy rays, ultraviolet rays, electron beams, etc. are usually used. The irradiation amount of energy rays is not particularly limited as long as the entire energy curable layer 11 can be fully cured and the coating film 4p can be cured, but in the case of ultraviolet rays, for example, the amount of light is 100 to 10,000 mJ. / cm ² is preferable, and 500 to 2,000 mJ / cm ² is particularly preferable.

  As described above, if the sheet 1 for producing an optical recording medium is used, the energy curable layer 11 and the hard coat layer 4 can be simultaneously cured by applying a single energy, so that the hard disk can be efficiently hardened with a small number of steps. An optical recording medium D having a coat layer can be produced.

  As described above, by manufacturing the optical recording medium D using the optical recording medium manufacturing sheet 1, the protective layer can be formed at low cost without using an expensive film substrate as the protective layer. . Further, since it is not necessary to provide a separate adhesive layer, the protective layer can be formed easily, and there is no problem of delamination or scattering of reflected light between the protective layer and the adhesive layer.

  In the optical recording medium manufacturing method, a single-sided single-layer optical recording medium is manufactured using the optical recording medium manufacturing sheet 1, but the present invention is not limited to this. For example, the optical recording medium A single-sided two-layer optical recording medium can be manufactured using the manufacturing sheet 1. Further, instead of the hard coat layer 4, another energy curable layer having a predetermined purpose may be formed.

  The embodiment described above is described for facilitating understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  For example, the substrate 12 ′ in the optical recording medium manufacturing sheet 1 may be omitted.

  EXAMPLES Hereinafter, although an Example etc. demonstrate this invention further more concretely, the scope of the present invention is not limited to these Examples etc.

[Example 1]
65 parts by mass of urethane acrylate as an energy curable oligomer (manufactured by Shin-Nakamura Chemical Co., Ltd., UA6100, mass average molecular weight (theoretical value): about 2300, solid content concentration 100% by mass, bifunctional), and energy curable monomer 35 parts by mass of isobornyl acrylate (manufactured by Kyoeisha Chemical Co., Ltd., light acrylate IB-XA, solid concentration 100% by mass) and 1-hydroxycyclohexyl phenyl ketone (manufactured by Ciba Specialty Chemicals Co., Ltd., Irgacure) as a photopolymerization initiator 184, solid concentration 100% by mass) and 3 parts by mass.

  The obtained energy curable material is a transparent base material made of polyethylene terephthalate (Toray Industries, Ltd., Lumirror T60, thickness: 50 μm, surface roughness (Ra): 0.001 μm; hereinafter referred to as “PET base material”. The film was applied using a knife coater so that the film thickness (target film thickness) of the energy curable layer (before the main curing) was 100 μm. In addition, the surface roughness (Ra) of the base material was measured using a surface roughness measuring machine (manufactured by Mitutoyo Corporation, SV-3100).

Then, the above-mentioned coating film (exposed surface is exposed to air) is irradiated with ultraviolet rays having an illuminance of 150 mW / cm ² and an amount of light of 40 mJ / cm ² using an ultraviolet irradiation device (H-bulb light source manufactured by Fusion UV Systems Japan). Irradiation from the film side formed an energy curable layer. The actual film thickness of this energy curable layer was 95 μm. The laminate thus obtained was used as an optical recording medium manufacturing sheet. In addition, the light quantity was measured using the light meter (The eye graphics company make, UV METER UVPF-36).

[Example 2]
97 parts by mass of urethane acrylate as an energy curable oligomer (manufactured by Nippon Synthetic Chemical Co., Ltd., UV-3210EA, mass average molecular weight (theoretical value): about 5000, solid content concentration 70% by mass, ethyl acetate diluted product, bifunctional), 3 parts by mass of phenoxyethyl acrylate (produced by Tokyo Chemical Industry Co., Ltd., solid concentration: 100% by mass, monofunctional) as an energy curable monomer and 1-hydroxycyclohexyl phenyl ketone (Ciba Specialty Chemicals) as a photopolymerization initiator Manufactured by Irgacure 184, solid content concentration of 100% by mass) and 3 parts by mass.

  For the production of an optical recording medium in the same manner as in Example 1 except that the obtained energy curable material was used and the energy curable material was applied on the base material, followed by a drying process at 100 ° C. for 2 minutes. A sheet was produced. The actual film thickness of the energy curable layer was 92 μm.

Example 3
62 parts by mass of urethane acrylate as an energy curable oligomer (manufactured by Negami Kogyo Co., Ltd., UV9000H, mass average molecular weight (measured value): about 5000, solid concentration 100% by mass, bifunctional) and isobol as an energy curable monomer 38 parts by mass of nyl acrylate (manufactured by Kyoeisha Chemical Co., Ltd., light acrylate IB-XA, solid content concentration 100% by mass) and 1-hydroxycyclohexyl phenyl ketone (manufactured by Ciba Specialty Chemicals, Irgacure 184) as a photopolymerization initiator (Solid content concentration 100% by mass) 3 parts by mass were mixed.

  Using the obtained energy curable material, a sheet for producing an optical recording medium was produced in the same manner as in Example 1. The actual film thickness of the energy curable layer was 98 μm.

Example 4
Urethane acrylate as an energy curable oligomer (manufactured by Negami Kogyo Co., Ltd., UV9000PEP, mass average molecular weight (actual measured value): about 5000, solid content concentration 100% by mass, bifunctional) 54 parts by mass and isovol as an energy curable monomer 46 parts by mass of nyl acrylate (manufactured by Kyoeisha Chemical Co., Ltd., light acrylate IB-XA, solid concentration 100% by mass) and 1-hydroxycyclohexyl phenyl ketone (manufactured by Ciba Specialty Chemicals, Irgacure 184) as a photopolymerization initiator (Solid content concentration 100% by mass) 3 parts by mass were mixed.

  Using the obtained energy curable material, a sheet for producing an optical recording medium was produced in the same manner as in Example 1. The actual film thickness of the energy curable layer was 98 μm.

Example 5
Urethane acrylate as an energy curable oligomer (manufactured by Nippon Synthetic Chemical Co., Ltd., UV6020EA, mass average molecular weight (theoretical value): about 800, solid content concentration 70% by mass, diluted ethyl acetate, bifunctional) 73 parts by mass, energy curing 49 parts by mass of isobornyl acrylate (Kyoeisha Chemical Co., Ltd., light acrylate IB-XA, solid concentration 100% by mass) as a photopolymerizable monomer, and 1-hydroxycyclohexyl phenyl ketone (Ciba Specialty Chemicals) as a photopolymerization initiator 3 parts by mass of Irgacure 184, solid content concentration of 100% by mass).

  For the production of an optical recording medium in the same manner as in Example 1 except that the obtained energy curable material was used and the energy curable material was applied on the base material, followed by a drying process at 100 ° C. for 2 minutes. A sheet was produced. The actual film thickness of the energy curable layer was 95 μm.

[Comparative Example 1]
The energy curable material obtained in Example 2 was applied onto a PET substrate in the same manner as in Example 1. Then, the coating film is irradiated with ultraviolet rays having an illuminance of 1000 mW / cm ² and a light quantity of 1000 mJ / cm ² from the coating film side by an ultraviolet irradiation device (manufactured by Fusion UV Systems Japan Co., Ltd., H bulb light source). A layer was formed. The actual film thickness of this energy curable layer was 92 μm. The laminate thus obtained was used as an optical recording medium manufacturing sheet.

[Comparative Example 2]
Urethane acrylate as an energy curable oligomer (manufactured by Negami Kogyo Co., Ltd., UV9000H, mass average molecular weight (actual measured value): about 5000, solid content concentration 100% by mass, bifunctional) 38 parts by mass and isovol as an energy curable monomer 62 parts by weight of nyl acrylate (manufactured by Kyoeisha Chemical Co., Ltd., light acrylate IB-XA, solid content concentration 100% by mass) and 1-hydroxycyclohexyl phenyl ketone (manufactured by Ciba Specialty Chemicals, Irgacure 184) as a photopolymerization initiator (Solid content concentration 100% by mass) 3 parts by mass were mixed.

  Using the obtained energy curable material, a sheet for producing an optical recording medium was produced in the same manner as in Comparative Example 1. The actual film thickness of the energy curable layer was 98 μm.

[Test example]
(1) Measurement of disappearance ratio of double bond About the sheet for optical recording medium production obtained in the example and the comparative example, a diamond ATR method using a Fourier transform infrared spectrometer (Perkin Elmer, Spectrum One) was used. The energy at each surface is determined by the reduction rate of the absorption peak near 810 cm ⁻¹ in the surface layer portion of the surface (first surface) and the exposed surface (second surface) of the energy curable layer in contact with the PET substrate. The disappearance ratio of the double bond of the curable component was determined. The absorption peak area of the energy curable component not irradiated with energy rays is 100%, and the illuminance is 1000 mW / cm ² using an ultraviolet irradiation device (made by Eye Graphics, ECS-401GX, high pressure mercury lamp H04-L41). The absorption peak area of the energy curable layer irradiated with ultraviolet rays having a light amount of 1000 mJ / cm ² was converted to 0%. Here, it is assumed that the absorption peak area and the number of double bonds are directly proportional. The results are shown in Table 1.

(2) Measurement of adhesive strength The first surface / second surface of the energy curable layer of the optical recording medium production sheet obtained in the examples and comparative examples are pressure-bonded to a SUS304 steel plate, and 180 in accordance with JIS Z0237. ° Peel adhesion was measured. In addition, the adherend was changed to a SUS304 steel plate to obtain a polycarbonate plate (manufactured by Mitsubishi Engineering Plastics, Iupilon NF-2000VU, 2 mm × 70 mm × 150 mm), and the adhesive strength was measured in the same manner. The results are shown in Table 1.

(3) Measurement of adhesive force The first surface / second surface of the energy curable layer of the optical recording medium production sheet obtained in the examples and comparative examples were pressure-bonded to a SUS304 steel plate. The energy curable layer of the laminate is irradiated with ultraviolet rays having an illuminance of 1000 mW / cm ² and a light quantity of 1000 mJ / cm ² by an ultraviolet irradiation device (Fusion UV Systems Japan, H bulb light source). Completely cured.

  About the 1st surface / 2nd surface of the obtained hardened layer, it peeled 180 degree | times according to JISZ0237, and measured adhesive force as adhesive force. Further, the adherend was changed to a SUS304 steel plate and a polycarbonate plate (manufactured by Mitsubishi Engineering Plastics Co., Ltd., Iupilon NF-2000VU, 2 mm × 70 mm × 150 mm) was measured in the same manner. The results are shown in Table 1.

(4) Confirmation of tackiness The first surface and the second surface of the energy curable layer of the optical recording medium production sheets obtained in the examples and comparative examples were each touched with a finger to confirm the presence or absence of the tackiness. . The results are shown in Table 1.

(5) Confirmation of bonding possibility Using the optical disk bonding apparatus disclosed in Japanese Patent Application Laid-Open No. 2003-151181, the second energy curable layer of the optical recording medium manufacturing sheet obtained in Examples and Comparative Examples is used. The surface was pressed onto a disc-shaped polycarbonate plate, and whether or not bonding was possible was confirmed. The results are shown in Table 1.

(6) Retardation measurement Illuminance of 1000 mW / cm on the energy curable layers of the optical recording medium production sheets obtained in the examples and comparative examples using an ultraviolet irradiation device (H bulb light source manufactured by Fusion UV Systems Japan). ^{2. After} irradiating ultraviolet rays with a light quantity of 1000 mJ / cm ² and peeling off the PET base material, the retardation was measured with a phase difference measuring device (manufactured by Oji Scientific Instruments, KOBRA-WR). The results are shown in Table 1.

(7) Measurement of 405 nm spectral transmittance The energy curable layer of the optical recording medium production sheet obtained in Examples and Comparative Examples was irradiated with an ultraviolet ray irradiation device (Fusion UV Systems Japan, H bulb light source) with an illuminance of 1000 mW. / cm ^2, was irradiated with ultraviolet light intensity 1000 mJ / cm ^2, after removing the PET substrate, a spectrophotometer (manufactured by Shimadzu Corporation, UV-3100PC) was measured 405nm spectral transmittance by. The results are shown in Table 1.

※ＰＣ：ポリカーボネート

* PC: Polycarbonate

  From Table 1, by setting the adhesive force and adhesive force of the energy curable layer of the optical recording medium production sheet produced in the examples to the ranges specified in the present invention, the first surface is an obstacle to the next step. It has been found that the second surface has a sufficient adhesion to the polycarbonate, which is the substrate material of the optical recording medium, in spite of the moderate surface state that does not become necessary. In addition, the energy curable layer of each optical recording medium production sheet had retardation and transparency suitable as a protective layer for the optical recording medium. That is, it was shown that each optical recording medium manufacturing sheet is suitable for both the optical recording medium manufacturing method and the constituent material.

  In addition, about the sheet | seat for optical recording medium manufacture produced in the Example, as shown in a test example (3), it affixed on the SUS304 steel plate and the polycarbonate plate, and irradiated the energy beam and hardened the energy curable layer completely. Thereafter, the adhesive strength of the energy curable layer is measured. The SUS304 steel plate and the polycarbonate plate are assumed to be constituent materials of the optical recording medium, and this test can be regarded as a pseudo performance test of the optical recording medium manufactured using the optical recording medium manufacturing sheet.

  The present invention is useful for producing an optical recording medium inexpensively, simply, efficiently, and with a good yield.

It is sectional drawing of the sheet | seat for optical recording medium manufacture which concerns on one Embodiment of this invention. It is a figure which shows the manufacturing method of the sheet | seat for optical recording medium manufacture concerning the embodiment. It is a figure which shows an example of the optical recording medium manufacturing method using the sheet | seat for optical recording medium manufacture concerning the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Sheet | seat for optical recording medium manufacture 11 ... Energy curable layer 12, 12 '... Base material 2 ... Optical recording medium board | substrate 3 ... Recording layer 4 ... Hard-coat layer (other layers of energy curable layer)

Claims (18)

An optical recording medium manufacturing sheet provided with an energy curable layer,
The adhesive strength of the first surface of the energy curable layer to the SUS304 steel plate or polycarbonate plate is less than 10 mN / 25 mm,
The sheet for manufacturing an optical recording medium, wherein the second surface of the energy curable layer has an adhesive strength to a SUS304 steel plate or a polycarbonate plate of 100 mN / 25 mm or more. An optical recording medium manufacturing sheet provided with an energy curable layer,
The adhesive strength of the first surface of the energy curable layer to the SUS304 steel plate or polycarbonate plate is less than 10 mN / 25 mm,
Adhering the second surface of the energy curable layer to the SUS304 steel plate or polycarbonate plate after the second surface of the energy curable layer is attached to either a SUS304 steel plate or a polycarbonate plate to completely cure the energy curable layer. A sheet for producing an optical recording medium, wherein the force is 100 mN / 25 mm or more.   The sheet for producing an optical recording medium according to claim 1, wherein the energy curable layer comprises a single layer.   The sheet for producing an optical recording medium according to any one of claims 1 to 3, wherein the energy curable layer is a layer that is cured by irradiation of energy rays, or a cured or semi-cured layer. The energy curable layer is obtained by curing or semi-curing a material mainly composed of an energy curable component having a polymerizable double bond by application of energy,
The disappearance ratio of the double bond of the energy curable component on the first surface of the energy curable layer is 60% or more, and more than the disappearance ratio of the double bond of the energy curable component on the second surface. The sheet for producing an optical recording medium according to any one of claims 1 to 4, wherein the amount is 15% or more.   6. The optical recording medium production according to claim 1, wherein the energy curable layer is obtained by curing or semi-curing a material mainly composed of an energy curable monomer and / or oligomer. Sheet.   The sheet for manufacturing an optical recording medium according to claim 6, wherein the content of the energy curable monomer in the material is 50% by mass or less and the content of the energy curable oligomer is 50% by mass or more. . Apply a coating agent containing a material whose main component is an energy curable component to the substrate,
A second surface opposite to the first surface in contact with the substrate of the obtained coating film is placed in the presence of oxygen;
When energy is applied to the coating film, the first surface of the coating film has an adhesive strength of less than 10 mN / 25 mm to the SUS304 steel plate or polycarbonate plate, and the second surface has an adhesive strength to the SUS304 steel plate or polycarbonate plate. A method for producing a sheet for producing an optical recording medium, wherein the coating film is cured or semi-cured so that the energy curable layer is formed so as to be 100 mN / 25 mm or more.   9. The method for producing a sheet for producing an optical recording medium according to claim 8, wherein another substrate is attached to the second surface of the formed energy curable layer.   The energy curable component has a polymerizable double bond, and by applying the energy, the energy curable component has a double bond of 60% or more on the first surface of the coating film, and the second 10. The method for producing a sheet for producing an optical recording medium according to claim 8, wherein the amount of the double bond of the energy curable component on the surface is eliminated by 15% or more.   The method for producing a sheet for producing an optical recording medium according to any one of claims 8 to 10, wherein the material contains an energy curable monomer and / or an oligomer as a main component.   12. The sheet for producing an optical recording medium according to claim 11, wherein the content of the energy curable monomer in the material is 50% by mass or less and the content of the energy curable oligomer is 50% by mass or more. Production method.   The method for producing a sheet for producing an optical recording medium according to any one of claims 8 to 12, wherein an energy beam is used as energy applied for forming the energy curable layer. A state in which the second surface of the energy curable layer in the optical recording medium manufacturing sheet according to any one of claims 1 to 7 is exposed,
Affixing the second surface of the energy curable layer to a recording layer of an optical recording medium;
A method for producing an optical recording medium, comprising forming a protective layer by applying energy to the energy curable layer to cure the energy curable layer.   15. The coating film of another energy curable layer is formed on the first surface of the energy curable layer before applying energy to the energy curable layer. The manufacturing method of the optical recording medium of description.   The method of manufacturing an optical recording medium according to claim 15, wherein the other layer of the energy curable property is a hard coat layer.   The method of manufacturing an optical recording medium according to claim 14, wherein an energy beam is used as energy applied for forming the protective layer. An optical recording medium manufactured using the optical recording medium manufacturing sheet according to claim 3 ,
The light curable layer of the optical recording medium production sheet is directly laminated on the recording layer of the optical recording medium and serves as a protective layer of the optical recording medium. recoding media.

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