JP2005116051A - Photocuring transfer sheet, method for manufacturing optical information recording medium using the same, and optical information recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photocuring transfer sheet, where a DVD or the like is thin, an optical information recording medium having high capacity is manufactured advantageously, and an even shape of an uneven substrate, or a stamper having projections and recesses, such as pits, can be easily transferred at a room temperature, when manufacturing the optical information recording medium. <P>SOLUTION: The photocuring transfer sheet has a photocuring transfer layer. In the photocuring transfer layer, a reactive polymer having a photopolymerization functional group is contained, and a storage elastic modulus at frequencies 1 Hz, 0.01 Hz, and 100 Hz are 1×10<SP>3</SP>to 9×10<SP>4</SP>Pa, 5×10<SP>3</SP>Pa or higher, and 1×10<SP>7</SP>Pa or lower, respectively, at 25°C. The optical information recording medium uses the photocuring transfer sheet. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical information recording medium in which information such as DVD (Digital Versatile Disc) and CD (Compact Disc) is recorded and / or recordable as digital signals such as large-capacity characters, sounds, and moving images. The present invention relates to a method and a photocurable transfer sheet advantageously used in these methods.

  Audio CDs and CD-ROMs are widely used as recorded optical information recording media with pits formed on the surface as digital signals. Recently, DVDs with pit recording on both sides capable of recording moving images and recordings have been made. As a next-generation recording medium for CD, it has been gradually used. In addition, CD-R, CD-RW, DVD-R, DVD-RW, and the like that can be recorded by a user in which pits and grooves are formed have attracted attention.

  For a DVD having recording layers on both sides, for example, as shown in FIG. 5, reflection layers 1a and 2a are respectively formed on the signal bit forming surfaces of two transparent resin substrates 1 and 2 each having a signal bit formed on one side. In the state in which the reflective layers 1a and 2a face each other, the substrates 1 and 2 are bonded and bonded via the adhesive layer 3, and the double-sided readout type, and as shown in FIG. In the substrates 1 and 2 on which the signal bits are formed, a semi-transparent layer 1b is formed on the signal bit surface of one substrate 1, and a reflective layer 2a is formed on the signal bit surface of the other substrate 2, and these semi-transparent reflective layers There is known a single-sided readout type in which substrates 1 and 2 are bonded and bonded via an adhesive layer 3 with 1b and a reflective layer 2a facing each other.

  On February 10, 2002, a unified standard “Blu-ray Disc” for the next generation optical disc was proposed. The main specifications are recording capacity: 23.3 / 25/27 GB, laser wavelength: 405 nm (blue-violet laser), lens numerical aperture (N / A): 0.85, disc diameter: 120 mm, disc thickness: 1.2 mm Track pitch: 0.32 μm or the like.

  As described above, the blu-ray disc has a narrow groove and a small pit. For this reason, it is necessary to narrow down the spot of the reading laser. However, if the spot is made smaller, it will be greatly affected by the tilt of the disc, and even if the DVD to be reproduced is slightly bent, it cannot be reproduced. In order to compensate for this disadvantage, it is considered to reduce the thickness of the substrate and to make the thickness of the cover layer on the pit on the laser irradiation side about 0.1 mm.

  Non-Patent Document 1, page 68 describes a DVD manufacturing method that meets the above requirements. This will be described with reference to FIG. A stamper made of polycarbonate having a reflective layer (or recording layer) 6a on the uneven surface provided by applying an ultraviolet curable resin 5A on the reflective layer of the disk substrate (1.1mm) 4a and having a reflective layer (or recording layer) on the uneven surface. An ultraviolet curable resin 5B is provided on 4b by coating. Next, the substrate is turned upside down, the substrate and the stamper are attached, and ultraviolet rays are irradiated from the stamper side to cure the ultraviolet curable resins 5A and 5B. The stamper 4b is removed from the layer of the ultraviolet curable resin 5B, a reflective layer (or recording layer) 6b is formed on the uneven surface, and a cover layer (thickness of about 0.1 mm) 7 is formed thereon.

  In the above method, an ultraviolet curable resin is provided on the surfaces of the disk substrate and the stamper by coating, and then the substrate is turned upside down and attached to the stamper. In this way, it is necessary to perform a complicated process of application and inversion, and when pasting the substrate and the stamper by inversion, there are disadvantages such as the generation of bubbles when contacting the viscous UV curable resins, There is a problem that good pasting cannot be performed. Further, the ultraviolet curable resin has a large shrinkage at the time of curing, and there is a problem that deformation such as warpage of the obtained medium is conspicuous.

Patent Document 1 proposes the use of an adhesive film having a specific storage elastic modulus (a storage elastic modulus at a frequency of 1 Hz is 1 × 10 ⁵ Pa or less at 25 ° C.) instead of the liquid ultraviolet curable resin. . The use of this adhesive film improves the followability to fine pits and the like formed on a signal recording layer such as a DVD-ROM, and improves the thickness accuracy of the light transmission layer. As the adhesive film, an acrylic resin having a polymer of (meth) acrylic acid and its ester as a main component and having a free unsaturated double bond is used.

JP 2002-241711 A NIKKEI ELECTRONICS, No. 2001.1.5

  However, when an optical disk is produced using an adhesive film having a specific storage modulus described in Patent Document 1, a vacuum laminator obtained by heating an adhesive film punched into a donut shape to 70 ° C. is used in advance. Bonding is performed with a heated DVD substrate. That is, when producing an optical disk using the adhesive film described in Patent Document 1, it is necessary to heat the film, the disk, etc., and if this can be performed at room temperature, it is extremely advantageous in productivity.

  Accordingly, the present invention provides a photocurable transfer sheet that is advantageous for the production of a high capacity optical information recording medium having a small thickness, such as a DVD, and is excellent in productivity. For that purpose.

  It is another object of the present invention to provide a method for manufacturing the optical information recording medium.

  It is another object of the present invention to provide a thin optical information recording medium obtained by the above manufacturing method.

The above object consists of a photocurable composition that can be deformed by pressurization, including a reactive polymer having a photopolymerizable functional group, and the storage elastic modulus at frequencies of 1 Hz, 0.01 Hz, and 100 Hz is 25 ° C., respectively. It can be achieved by a photocurable transfer sheet having a photocurable transfer layer of 1 × 10 ^{3 to} 9 × 10 ⁴ Pa, 5 × 10 ³ Pa or more, and 1 × 10 ⁷ Pa or less.

  In the photocurable transfer sheet, the photocurable composition generally further contains a plasticizing reactive diluent having a molecular weight of 1000 or less and having a photopolymerizable functional group. The amount of the plasticizing reactive diluent is 10% by mass or more (particularly 20% by mass or more, especially 25% by mass or more; the upper limit is preferably 40% by mass) based on the total amount of the photocurable composition. Is preferred. The plasticizing reactive diluent having a photopolymerizable functional group is generally a di (meth) acrylate of an (preferably linear) alkanediol, particularly preferably having 3 to 10 carbon atoms in the alkanediol. preferable. Acrylate is particularly preferable.

  The glass transition temperature of the photocurable composition is generally 20 ° C. or lower (particularly 15 ° C. to −10 ° C.), and particularly the glass transition temperature of the reactive polymer is 20 ° C. or lower (particularly 15 ° C. to −10 ° C.). )). It is advantageous for improving the transferability of the uneven surface.

  The reactive polymer preferably contains 1 to 50 mol% of a photopolymerizable functional group in order to obtain appropriate curability and cured film strength. The photopolymerizable functional group is preferably a (meth) acryloyl group from the viewpoint of curability. The photocurable composition preferably contains 0.1 to 10% by mass of a photopolymerization initiator in order to obtain appropriate curability. The photocurable transfer sheet preferably has a thickness of 1 to 1200 μm (particularly 5 to 300 μm) from the viewpoint of transferability and workability. The number average molecular weight of the reactive polymer is preferably 10,000 to 300,000, and the weight average molecular weight is preferably 10,000 to 300,000. This is preferable from the viewpoint of transferability and workability.

  The light curable transfer sheet preferably has a light transmittance of 70% or more in a wavelength region of 380 to 420 nm (preferably a wavelength region of 380 to 600 nm, particularly 380 to 800 nm). When a signal is read from the obtained medium with a laser, an error-free operation is guaranteed. It is preferable that the curing shrinkage ratio of the photocurable transfer sheet is 8% or less.

  The photocurable transfer layer preferably contains transparent fine particles. Thereby, even in the state of a roll of a long sheet, there can be obtained a photocurable transfer sheet in which the components of the photocurable transfer layer are not exuded and the thickness of the sheet does not vary.

  The fact that the release sheet is provided on one or both surfaces of the photocurable transfer layer improves the actual production efficiency. The photo-curable transfer sheet is long and the photo-curable transfer layer and the release sheet have approximately the same width (so-called full edge; but can also be used at the dry edge) to improve workability and reduce costs. It is valid.

Using the photocurable transfer sheet of the present invention, the following steps (2) to (4):
(2) The process of removing one peeling sheet of the said photocurable transfer sheet;
(3) Photocuring of the photocurable transfer sheet on the reflective layer of the substrate having irregularities as recording pits and / or grooves on the surface and further provided with a reflective layer along the irregularities on the irregular surface. A laminate in which the surface of the light-sensitive transfer layer is placed in contact with the uneven surface of the reflective layer, and the surface of the photocurable transfer sheet is adhered along the uneven surface of the reflective layer by pressing them. A step of forming; and (4) a step of removing the other release sheet from the laminate,
An optical information recording medium can be obtained by carrying out a manufacturing method characterized by including:

In addition, before the step (2),
(1) A step of punching the photocurable transfer sheet into a disc shape (generally having a through hole in the center); or (1) A photocurable transfer layer of the photocurable transfer sheet and one release sheet are formed into a disc. Punching into a shape and leaving the other release sheet as it is;
It is preferable to carry out.

    In the latter case, in the step (2), it is preferable to remove the release sheet on the punched side.

After performing the step (4), (5) the uneven surface of the stamper having unevenness as recording pits and / or grooves on the surface of the photocurable transfer layer from which the release sheet of the laminate has been removed. Placing and pressing them to form a laminate in which the surface of the photocurable transfer sheet is in close contact with the uneven surface;
(6) A step of providing irregularities on the surface of the photocurable transfer layer by curing the photocurable transfer layer of the laminate having the stamper by ultraviolet irradiation and then removing the stamper;
It is common to include.

After performing the step (6), further (7) a step of providing a reflective layer on the uneven surface of the photocurable transfer layer;
Can also be included.

  The present invention also resides in an optical information recording medium obtained by the above manufacturing method.

  The photo-curable transfer sheet of the present invention is a photo-curable transfer sheet that is advantageous for the production of a high-capacity optical information recording medium such as a DVD, and the optical information recording medium can be obtained by using this sheet. It is possible to easily transfer the concavo-convex shape of a substrate having a concavo-convex structure such as pits or a stamper in the vicinity of room temperature during manufacturing. That is, in the photocurable transfer layer of the present invention, the storage elastic modulus before curing is set in a specific range, and thus, room temperature transfer can be performed very easily and with excellent unevenness followability. In addition, there are no adverse effects (for example, fluctuations in the thickness of the transfer layer in the production of optical information recording media) associated with improved transferability.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a cross-sectional view showing an example of an embodiment of a photocurable transfer sheet 10 used in the present invention. The photocurable transfer layer 11 has release sheets 12a and 12b on both sides. The release sheet may be either one or not. It is set appropriately according to the usage mode.

The photocurable transfer layer 11 is a layer having a specific storage elastic modulus so that it can be accurately transferred even at normal temperature by pressing the uneven surface of the stamper. That is, the photocurable transfer layer 11 has storage elastic moduli at frequencies of 1 Hz, 0.01 Hz, and 100 Hz of 1 × 10 ^{3 to} 9 × 10 ⁴ Pa, 5 × 10 ³ Pa or more at 25 ° C. respectively (especially 8 × 10 ³ Pa or higher) and 1 × 10 ⁷ Pa or lower (particularly 5 × 10 ⁶ Pa or lower). The glass transition temperature of the photocurable composition (particularly reactive polymer) constituting the photocurable transfer layer 11 is preferably 20 ° C. or lower (particularly 15 ° C. to −10 ° C.). In order to increase the density of information, it is preferable that the layer has a light transmittance of 70% or more in a wavelength region of 380 to 420 nm so that reading with a reproducing laser can be easily performed. In particular, a layer having a light transmittance of 80% or more in a wavelength region of 380 to 420 nm is preferable. Therefore, the optical information recording medium of the present invention produced using this transfer sheet can be advantageously used in a method of reproducing a pit signal using a laser having a wavelength of 380 to 420 nm.

  Using the photocurable transfer sheet 10, the optical information recording medium of the present invention can be produced, for example, as shown in FIG.

  In general, the photocurable transfer sheet 10 is first punched into a disc shape (generally a donut shape having a through hole in the center). At this time, when the photocurable transfer layer 11 and all of the release sheets 12a and 12b on both sides are punched out, the photocurable transfer layer 11 and one of the release sheets 12b are punched into a disk shape, and the other release sheet 12a is left as it is. In some cases, it is selected as appropriate (1). As described above, the punching operation in advance is advantageous in that the photocurable transfer sheet of the present invention contains, for example, transparent fine particles, so that the transfer layer does not ooze out and does not bleed out with good workability.

Next, the release sheet 12a is removed from the photocurable transfer sheet 10, and a photocurable transfer layer with the release sheet 12b is prepared (2). Photocurability with the side without the release sheet facing the translucent reflective layer 23 (generally a reflective layer having a relatively low reflectivity such as AgX) of the irregular surface of the substrate 21 having irregularities as recording pits on the surface. The transfer sheet 11 is pressed (3). As a result, a laminate (consisting of 11, 23, 21) is formed in which the surface of the photocurable transfer sheet is adhered along the uneven surface. When used as an optical information recording medium with this configuration, the photocurable transfer sheet 11 is cured by ultraviolet irradiation, and the release sheet 12b is removed (4). Since the photocurable transfer sheet of the present invention has the specific storage elastic modulus, the surface thereof can be brought into close contact with the uneven surface of the substrate with extremely excellent followability near room temperature. it can.
Next, the stamper 24 having irregularities as recording pits on the surface is pressed against the surface of the uncured photocurable transfer sheet 11 (the surface not in contact with the substrate) by removing the release sheet 12b from the laminate. (5). A laminate (comprising 21, 23, 11, 24) in which the surface of the photocurable transfer sheet 11 is in close contact with the uneven surface of the stamper 24 is formed, and the photocurable transfer sheet of the laminate is cured by ultraviolet irradiation. After removing (6), the stamper 24 is removed to provide irregularities such as recording pits on the surface of the cured sheet. As a result, a laminate (optical information recording medium) including the substrate 11, the reflective layer 23, and the cured photocurable transfer sheet 11 is obtained. Usually, a reflective layer (generally a reflective layer having a high reflectance such as Al)) 25 is provided on the unevenness (surface of the cured sheet) (7), and an organic polymer film (cover layer) 26 is further provided thereon as an adhesive. Paste through the layer (8). A photocurable transfer sheet may be further pressed onto the surface of the cured sheet having recording pits and cured by ultraviolet irradiation. Alternatively, an ultraviolet curable resin may be applied and cured on the surface of the cured sheet. The translucent reflective layer may be a normal reflective layer such as Al (for double-sided readout). The reflective layer 25 may be a translucent reflective layer, and the translucent reflective layer 23 may be a highly reflective reflective layer.

  In the above method, the read-only optical information recording medium has been described. However, the same method can be applied to a recordable optical information recording medium. In the case of a recordable medium, it has grooves or grooves and pits. In this case, instead of the reflective layer and the translucent reflective layer, a metal recording layer (in the case of a dye recording layer or when the reflectance of the metal recording layer is low, Recording layer and reflective layer) are generally provided. Otherwise, the optical information recording medium can be manufactured in the same manner as described above.

  In the present invention, the concavo-convex shape which is the recording pits and / or grooves of the substrate 21 presses the photocurable transfer layer 11 and the substrate 21 at a relatively low temperature (preferably normal temperature) of 50 ° C. or less (preferably reduced pressure). The photo-curable transfer sheet is designed so that it can be accurately transferred. Superposition of the substrate 21 and the photocurable transfer layer 11 is generally performed with a pressure roll or a simple press (preferably under reduced pressure). Further, the cured layer of the photocurable transfer layer 11 has a good adhesive force with the metal used for the reflective layer on the surface of the substrate 21 and does not peel off. If necessary, an adhesion promoting layer may be provided on the reflective layer.

  Similarly, the concavo-convex shape which is a recording pit and / or groove of the stamper 24 presses the photocurable transfer layer 11 and the stamper 24 at a low temperature (preferably normal temperature) of 50 ° C. or less (preferably under reduced pressure). Therefore, the photocurable transfer sheet is designed so that the transfer is accurately performed. The stacking of the stamper 21 and the photocurable transfer sheet 11 is generally performed by a pressure roll or a simple press (preferably under reduced pressure). Further, the cured layer of the photocurable transfer layer 11 has extremely weak adhesive force with a metal such as nickel used for the stamper, and the photocurable transfer sheet can be easily peeled from the stamper.

  Since the substrate 21 is generally a thick plate (usually about 0.3 to 1.5 mm, particularly about 1.1 mm), it is generally produced by a conventional injection molding method. However, you may manufacture using a photocurable transfer sheet and a stamper. Since the photocurable transfer sheet of the present invention can be thinned to 300 μm or less (preferably 150 μm or less), the other substrate can be produced by a conventional method, and the thickness of the substrate can be increased. Transfer accuracy can be increased.

  In the above step, when pressing the photocurable transfer layer against the substrate or when pressing the stamper against the photocurable transfer layer, it is preferable to press under reduced pressure. Thereby, the removal of bubbles and the like are performed smoothly.

  The pressing under reduced pressure may be performed, for example, by passing a photocurable transfer sheet and a stamper between two rolls under reduced pressure, or using a vacuum forming machine, placing the stamper in a mold and reducing the pressure. Examples thereof include a method in which a photocurable transfer sheet is pressure-bonded to a stamper.

  In addition, pressing under reduced pressure can be performed using a double vacuum chamber type apparatus. This will be described with reference to FIG. FIG. 4 shows an example of a double vacuum chamber type laminator. The laminator includes a lower chamber 41, an upper chamber 42, a silicone rubber sheet 43, and a heater 45. In the lower chamber 41 in the laminator, a laminate 49 of a substrate having unevenness and a photocurable transfer sheet, or a laminate 49 of a substrate, a photocurable transfer sheet, and a stamper is placed. Both the upper chamber 42 and the lower chamber 41 are evacuated (depressurized). The laminated body 49 is heated by the heater 45 as necessary, and then the upper chamber 42 is returned to atmospheric pressure while the lower chamber 41 is evacuated, and the laminated body is pressure-bonded. Cool and take out the laminate and move to the next step. Thereby, defoaming is sufficiently performed at the time of exhaust, and the stamper or the substrate and the photocurable transfer sheet can be pressure-bonded without any bubbles.

The photocurable transfer sheet 10 used in the present invention is composed of a photocurable composition containing a reactive polymer having a photopolymerizable functional group, and the photocurable transfer layer 11 having the specific storage elastic modulus. It is what you have.
The photocurable composition of the present invention is generally a reactive polymer having a photopolymerizable functional group (generally having a glass transition temperature of 20 ° C. or lower), and a photopolymerizable functional group (preferably a (meth) acryloyl group). ) Having a plasticizing reactive diluent (monomers and oligomers), a photopolymerizable initiator, and optionally other additives.

The photocurable transfer layer 11 is a layer having a specific storage elastic modulus so that it can be accurately transferred near normal temperature by pressing the uneven surface of the stamper. That is, the photocurable transfer layer 11 has storage elastic moduli at frequencies of 1 Hz, 0.01 Hz, and 100 Hz of 1 × 10 ^{3 to} 9 × 10 ⁴ Pa, 5 × 10 ³ Pa or more at 25 ° C. respectively (especially 8 × 10 ³ Pa or higher) and 1 × 10 ⁷ Pa or lower (particularly 5 × 10 ⁶ Pa or lower). The storage elastic modulus at 0.01 Hz is related to the storage stability when uncured, and when this value is less than 5 × 10 ³ Pa, oozing from the end occurs when stored in a roll state, Variations in the thickness of the transfer layer occur. The storage elastic modulus at 100 Hz is related to the hardness when transferring uneven shapes such as pits with a stamper or the like, and when this value exceeds 1 × 10 ⁷ Pa, the transferability at the transfer temperature is not sufficient and the uneven shape Is not accurately transcribed. The storage modulus at a frequency of 1 Hz is related to both of the above characteristics. At a frequency of 1 Hz, if it is less than 1 × 10 ³ Pa, the uncured thickness tends to change, and if it exceeds 9 × 10 ⁴ Pa, transfer failure tends to occur.

  The photocurable transfer layer having the specific storage elastic modulus can be obtained mainly by a suitable combination of types and amounts of the reactive polymer and the plasticizing reactive diluent.

  Examples of the reactive polymer having a photopolymerizable functional group include alkyl acrylate (eg, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate) and / or alkyl methacrylate (eg, methyl methacrylate, ethyl methacrylate, butyl methacrylate, A homopolymer or copolymer (namely, acrylic resin) obtained from 2-ethylhexyl methacrylate) and having a photopolymerizable functional group in the main chain or side chain. Such a polymer is obtained, for example, by copolymerizing one or more kinds of (meth) acrylate and (meth) acrylate having a functional group such as hydroxyl group (eg, 2-hydroxyethyl (meth) acrylate). The polymer can be obtained by reacting with a functional group of the polymer and a compound having a photopolymerizable group, such as isocyanatoalkyl (meth) acrylate. Therefore, an acrylic resin having a photopolymerizable functional group via a urethane bond is preferable.

  The reactive polymer of the present invention preferably contains 1 to 50 mol%, particularly 5 to 30 mol% of a photopolymerizable functional group. This photopolymerizable functional group is generally a group having an unsaturated double bond, and preferred examples thereof include acryloyl group, methacryloyl group, vinyl group, particularly acryloyl group, and methacryloyl group.

  The glass transition temperature of the reactive polymer is generally 20 ° C. or lower, and when the glass transition temperature is 20 ° C. or lower, when the resulting photocurable transfer layer is pressure-bonded to the uneven surface of the stamper, at room temperature. Can also be flexible enough to closely follow the uneven surface. In particular, followability is excellent when the glass transition temperature is in the range of 15 ° C to -50 ° C (particularly 15 ° C to -10 ° C). If the glass transition temperature is too high, a high pressure and a high pressure are required at the time of attachment, leading to a decrease in workability. If it is too low, a sufficient altitude after curing cannot be obtained.

  Further, the reactive polymer of the present invention generally has a number average molecular weight of 5,000 to 1,000,000, preferably 10,000 to 300,000, and the weight average molecular weight is generally 5,000 to 1,000,000, preferably 10,000 to 300,000.

  The plasticizing reactive diluent is a compound capable of plasticizing the photocurable transfer layer before curing, and includes, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meta ) Acrylate, 2-ethylhexyl polyethoxy (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, phenyloxyethyl (meth) acrylate, tricyclodecane mono (meth) acrylate, dicyclopentenyloxyethyl (meth) Acrylate, tetrahydrofurfuryl (meth) acrylate, acryloylmorpholine, N-vinylcaprolactam, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, o-phenylphenyloxyethyl (meth) acrylate , Neopentyl glycol di (meth) acrylate, neopentyl glycol dipropoxy di (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, tricyclodecane dimethylol di (meth) acrylate, 1,6-hexane Diol di (meth) acrylate, nonanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, tris [(meth) acryloxyethyl] isocyanate (Meth) acrylate monomers such as nurate and ditrimethylolpropane tetra (meth) acrylate, polyol compounds (for example, ethylene glycol, propylene glycol, Pentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 2-ethyl-2-butyl-1,3-propanediol, trimethylolpropane, diethylene glycol, diethylene glycol Polyols such as propylene glycol, polypropylene glycol, 1,4-dimethylolcyclohexane, bisphenol A polyethoxydiol, polytetramethylene glycol, the polyols and succinic acid, maleic acid, itaconic acid, adipic acid, hydrogenated dimer acid, Polyester polyols which are reaction products of polybasic acids such as phthalic acid, isophthalic acid and terephthalic acid or their anhydrides, polycaprolactone polyols which are reaction products of the polyols and ε-caprolactone, the polyols Kind Reaction products of polybasic acids or their anhydrides with ε-caprolactone, polycarbonate polyols, polymer polyols, etc.) and organic polyisocyanates (for example, tolylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, diphenylmethane-4, 4′-diisocyanate, dicyclopentanyl diisocyanate, hexamethylene diisocyanate, 2,4,4′-trimethylhexamethylene diisocyanate, 2,2 ′, 4-trimethylhexamethylene diisocyanate, etc.) and a hydroxyl group-containing (meth) acrylate (for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenyloxypro Polyurethane (meth) acrylate, bisphenol A type, which is a reaction product of pill (meth) acrylate, cyclohexane-1,4-dimethylol mono (meth) acrylate, pentaerythritol tri (meth) acrylate, glycerin di (meth) acrylate, etc. Examples thereof include (meth) acrylate oligomers such as bisphenol type epoxy (meth) acrylate which is a reaction product of bisphenol type epoxy resin such as epoxy resin and bisphenol F type epoxy resin and (meth) acrylic acid. These plasticizing reactive diluents having a photopolymerizable functional group can be used alone or in combination.

  Among these, compounds having a molecular weight of 1000 or less, more preferably 500 or less, and particularly 200 to 400 are preferable. Bifunctional compounds are preferred. Preferred compounds include tricyclodecane dimethylol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, nonanediol di (meth) acrylate, 1,4-butanediol and the like (in the present invention). Then, acrylates are particularly preferable). The amount of the plasticizing reactive diluent is 10% by mass or more (particularly 20% by mass or more, especially 25% by mass or more; the upper limit is preferably 40% by mass) based on the total amount of the photocurable composition. Is preferred. The mass ratio of the reactive polymer to the plasticizing reactive diluent is generally 60:10 to 50, preferably 60:20 to 50, and particularly preferably 60:20 to 45.

  As the photopolymerization initiator, any known photopolymerization initiator can be used, but one having good storage stability after blending is desirable. Examples of such photopolymerization initiators include benzoin series such as acetophenone series and benzyldimethyl ketal, thiophenone series such as benzophenone series, isopropylthioxanthone, and 2-4-diethylthioxanthone, and other special types include methylphenylglycol. Oxylate can be used. Particularly preferably, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- (4- (methylthio) phenyl) -2-morpholinopropane-1, Examples include benzophenone. These photopolymerization initiators may contain one or two or more kinds of known and commonly used photopolymerization accelerators such as benzoic acid-based or tertiary amine-based compounds such as 4-dimethylaminobenzoic acid as required. Can be mixed and used. Moreover, it can be used by 1 type, or 2 or more types of mixture of only a photoinitiator. In general, the photocurable composition preferably contains a photopolymerization initiator in an amount of 0.1 to 20% by mass, particularly 1 to 10% by mass.

  Among the photopolymerization initiators, examples of the acetophenone-based polymerization initiator include 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, 4-t-butyl-trichloroacetophenone, diethoxyacetophenone, and 2-hydroxy-2. -Methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 1- (4-dodecylphenyl) -2-hydroxy-2-methyl Propan-1-one, 4- (2-hydroxyethoxy) -phenyl (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- (4- (methylthio) phenyl) -2 As benzophenone polymerization initiators such as morpholinopropane-1, Benzophenone, benzoyl benzoate, methyl benzoyl benzoate, 4-phenyl benzophenone, hydroxybenzophenone, 4-Benzzoiru 4'-methyl diphenyl sulfide, etc. 3,3'-dimethyl-4-methoxybenzophenone may be used.

  As the acetophenone-based polymerization initiator, in particular, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- (4- (methylthio) phenyl) -2 -Morpholinopropane-1 is preferred. As the benzophenone polymerization initiator, benzophenone, benzoylbenzoic acid, and methyl benzoylbenzoate are preferable. Tertiary amine photopolymerization accelerators include triethanolamine, methyldiethanolamine, triisopropanolamine, 4,4'-dimethylaminobenzophenone, 4,4'-diethylaminobenzophenone, ethyl 2-dimethylaminobenzoate. , Ethyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate (n-butoxy), isoamyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate and the like can be used. Particularly preferably, as the photopolymerization accelerator, ethyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate (n-butoxy), isoamyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, etc. Is mentioned.

  As another additive, a silane coupling agent (adhesion promoter) can be added. As this silane coupling agent, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxy Propyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-chloropropylmethoxysilane, vinyltrichlorosilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β There are (aminoethyl) -γ-aminopropyltrimethoxysilane and the like, and one of these can be used alone or two or more of them can be used in combination. The addition amount of these silane coupling agents is usually 0.01 to 5 parts by mass with respect to 100 parts by mass of the reactive polymer.

  Similarly, an epoxy group-containing compound can be added for the purpose of improving adhesiveness. Examples of the epoxy group-containing compound include triglycidyl tris (2-hydroxyethyl) isocyanurate; neopentyl glycol diglycidyl ether; 1,6-hexanediol diglycidyl ether; acrylic glycidyl ether; 2-ethylhexyl glycidyl ether; Examples thereof include phenol glycidyl ether; pt-butylphenyl glycidyl ether; adipic acid diglycidyl ester; o-phthalic acid diglycidyl ester; glycidyl methacrylate; Further, the same effect can be obtained by adding an oligomer containing an epoxy group having a molecular weight of several hundred to several thousand or a polymer having a weight average molecular weight of several thousand to several hundred thousand. The addition amount of these epoxy group-containing compounds is sufficient to be 0.1-20 parts by mass with respect to 100 parts by mass of the reactive polymer, and at least one of the epoxy group-containing compounds can be added alone or in combination. .

  As another additive, a hydrocarbon resin can be added for the purpose of improving workability such as workability and bonding. In this case, the added hydrocarbon resin may be either a natural resin type or a synthetic resin type. In natural resin systems, rosin, rosin derivatives, and terpene resins are preferably used. For rosin, gum-based resins, tall oil-based resins, and wood-based resins can be used. As the rosin derivative, rosin obtained by hydrogenation, heterogeneity, polymerization, esterification, or metal chloride can be used. As the terpene resin, a terpene phenol resin can be used in addition to a terpene resin such as α-pinene and β-pinene. In addition, dammar, corbal and shellac may be used as other natural resins. On the other hand, in the synthetic resin system, petroleum resin, phenol resin, and xylene resin are preferably used. As the petroleum resin, aliphatic petroleum resin, aromatic petroleum resin, alicyclic petroleum resin, copolymer petroleum resin, hydrogenated petroleum resin, pure monomer petroleum resin, and coumarone indene resin can be used. As the phenol resin, an alkyl phenol resin or a modified phenol resin can be used. As the xylene-based resin, a xylene resin or a modified xylene resin can be used.

  Acrylic resin can also be added. For example, a homopolymer or copolymer obtained from alkyl acrylate (eg, methyl acrylate, ethyl acrylate, butyl acrylate) and / or alkyl methacrylate (eg, methyl methacrylate, ethyl methacrylate, butyl methacrylate) can be mentioned. Moreover, the copolymer of these monomers and another copolymerizable monomer can also be mentioned. In particular, polymethyl methacrylate (PMMA) is preferable from the viewpoints of reactivity during photocuring, durability after curing, and transparency.

  Although the addition amount of polymers, such as the said hydrocarbon resin, is selected suitably, 1-20 mass parts is preferable with respect to 100 mass parts of said reactive polymers, More preferably, it is 5-15 mass parts.

  The photocurable transfer layer of the present invention preferably contains transparent fine particles having an average particle size of 300 nm or less. Thereby, without impairing the transferability, photocurability, etc. of the photocurable transfer layer composed of a photocurable composition such as a reactive polymer, from the side surface when the photocurable transfer sheet is rolled. It is intended to greatly suppress the bleeding and exudation of the transfer layer component and the variation in sheet thickness.

  The transparent fine particles may be inorganic fine particles or organic fine particles as long as they have transparency and an average particle size of 300 nm or less. Examples of the inorganic fine particles include glass beads, talc, silica, alumina, magnesia, zinc white, calcium carbonate, barium sulfate, titanium dioxide, aluminum hydroxide, mica, feldspar powder, and quartz powder. Examples of the fine particles include acrylic resin (eg, polymethyl methacrylate (PMMA)), polystyrene, styrene / acrylic copolymer, polyethylene, epoxy resin, silicone resin, polyvinylidene fluoride, Teflon (registered trademark), divinylbenzene / styrene. Examples thereof include fine particles of a copolymer, phenol resin, polyurethane, cellulose acetate, nylon, cellulose, benzoguanamine resin, and melamine resin. As the transparent fine particles, silica, titanium dioxide and polymethyl methacrylate are preferable, and silica fine particles are particularly preferable. These fine particles generally have an average particle size of 1 to 300 nm, preferably 1 to 200 nm. If it exceeds 300 nm, the transferability tends to decrease. On the other hand, if it is too small, the bleeding suppression effect of the present invention tends to decrease.

The silica fine particles preferably have an average particle diameter (primary particle diameter) of 1 to 300 nm, more preferably 1 to 200 nm, and particularly preferably 10 to 100 nm. The silica fine particles are powdery silica or colloidal silica, and the shape thereof is spherical, hollow, porous, rod-like, plate-like, fibrous, or indeterminate, and preferably spherical. The specific surface area of the silica fine particles is generally ^{0.1~3000m 2 / g, 10~1500m 2 /} g are preferred. The fine pore volume of the silica fine particles is generally 0.1 to 5 ml / g, preferably 0.2 to 2 ml / g.

  Preferable examples include Aerosil 130, Aerosil 300, Aerosil 380, Aerosil TT600 and Aerosil OX50; Nipsil VN-3 manufactured by Nippon Silica Kogyo Co., Ltd .; Chemisnow MP manufactured by Soken Chemical Co., Ltd.

  The transparent fine particles are generally contained in the photocurable composition in an amount of generally 0.5 to 20% by mass, particularly 1 to 10% by mass. Setting within this range is particularly advantageous for maintaining transparency while suppressing seepage and variation in sheet thickness.

  In addition to the above additives, the photocurable composition of the present invention may contain a small amount of an ultraviolet absorber, an antioxidant, a dye, a processing aid and the like.

  A photocurable transfer sheet comprising the photocurable composition of the present invention comprises the above reactive polymer, a plasticizing reactive diluent (monomer and oligomer) having a photopolymerizable functional group, and optionally other additives. Are uniformly mixed and kneaded with an extruder, roll, etc., and then formed into a predetermined shape by a film forming method such as calendar, roll, T-die extrusion, inflation or the like. When using a support (generally a release sheet), it is necessary to form a film on the support. More preferably, the photocurable adhesive film-forming method of the present invention is obtained by uniformly mixing and dissolving each constituent component in a good solvent, and then applying this solution to a separator precisely coated with silicone or fluororesin. , A gravure roll method, a Myer bar method, a lip die coating method, or the like is used to form a film by coating on a support and drying the solvent.

  The thickness of the photocurable transfer sheet is preferably 1 to 1200 μm, particularly preferably 5 to 500 μm. Particularly preferred is 5 to 300 μm (preferably 150 μm or less). If it is thinner than 1 μm, the sealing performance is poor, and the unevenness of the transparent resin substrate may not be filled. On the other hand, if the thickness is larger than 1000 μm, the thickness of the recording medium increases, which may cause problems in the storage and assembly of the recording medium, and may also affect the light transmission.

  It is preferable that a release sheet is attached to one side or both sides of the photocurable transfer sheet.

  As a material for the release sheet, a transparent organic resin having a glass transition temperature of 50 ° C. or higher is preferable. As such a material, polyester resins such as polyethylene terephthalate, polycyclohexylene terephthalate, polyethylene naphthalate, nylon 46, modified In addition to polyamide resins such as nylon 6T, nylon MXD6, polyphthalamide, ketone resins such as polyphenylene sulfide and polythioether sulfone, sulfone resins such as polysulfone and polyether sulfone, polyether nitrile, polyarylate, Use a transparent resin substrate mainly composed of an organic resin such as polyetherimide, polyamideimide, polycarbonate, polymethyl methacrylate, triacetyl cellulose, polystyrene, polyvinyl chloride, etc. Can. Of these, polycarbonate, polymethyl methacrylate, polyvinyl chloride, polystyrene, and polyethylene terephthalate can be suitably used. The thickness is preferably 10 to 200 μm, particularly preferably 30 to 100 μm.

  As a material for the substrate 21 having signal recording irregularities on its surface, a transparent organic resin having a glass transition temperature of 50 ° C. or higher is preferable. As such a support, polyethylene terephthalate, polycyclohexylene terephthalate, polyethylene naphthalate is used. Polyester resins such as phthalates, polyamide resins such as nylon 46, modified nylon 6T, nylon MXD6 and polyphthalamide, ketone resins such as polyphenylene sulfide and polythioether sulfone, and sulfone resins such as polysulfone and polyether sulfone Besides, organic resins such as polyether nitrile, polyarylate, polyether imide, polyamide imide, polycarbonate, polymethyl methacrylate, triacetyl cellulose, polystyrene, polyvinyl chloride, etc. It can be a transparent resin substrate having a main component. Among these, polycarbonate, polymethyl methacrylate, polyvinyl chloride, polystyrene, and polyethylene terephthalate are excellent in terms of transferability and birefringence, and can be suitably used. The thickness is preferably 200 to 2000 μm, particularly preferably 500 to 1500 μm.

  The organic polymer film material 26 is preferably a transparent organic resin having a glass transition temperature of 50 ° C. or higher. Examples of such a support include polyester resins such as polyethylene terephthalate, polycyclohexylene terephthalate, and polyethylene naphthalate, and nylon. 46, modified nylon 6T, nylon MXD6, polyamide resins such as polyphthalamide, ketone resins such as polyphenylene sulfide and polythioether sulfone, polysulfone, sulfone resins such as polyether sulfone, polyether nitrile, Transparent tree mainly composed of organic resins such as polyarylate, polyetherimide, polyamideimide, polycarbonate, polymethyl methacrylate, triacetyl cellulose, polystyrene, polyvinyl chloride Substrate can be used. Among these, polycarbonate, polymethyl methacrylate, polyvinyl chloride, polystyrene, and polyethylene terephthalate are excellent in terms of transferability and birefringence, and can be suitably used. The thickness is preferably 10 to 200 μm, particularly preferably 50 to 100 μm.

  The photocurable transfer sheet thus obtained in the present invention is composed of a photocurable composition containing a reactive polymer having a glass transition temperature of 20 ° C. or lower, and is further 380 to 420 nm of the photocurable transfer layer. The light transmittance in the wavelength region is preferably 70% or more. That is, by setting the glass transition temperature to 20 ° C. or lower, when the photocurable transfer layer is pressure-bonded to the uneven surface of the stamper, the glass transition temperature can be flexible to closely follow the uneven surface. In particular, the tracking property is excellent when the glass transition temperature is in the range of 15 ° C to -50 ° C (particularly 15 ° C to -10 ° C). If the glass transition temperature is too high, a high pressure and high temperature are required at the time of attachment, which leads to a decrease in workability. If it is too low, a sufficient altitude after curing cannot be obtained.

  The photocurable transfer sheet has a light transmittance of 70% or more in a wavelength region of 380 to 420 nm (preferably 380 to 800 nm), in order to prevent a decrease in intensity of a read signal by a laser. Furthermore, the light transmittance in the wavelength region of 380 to 420 nm is preferably 80% or more.

  The reactive polymer in the photocurable composition preferably has 1 to 50 mol% of a polymerizable functional group. Thereby, the intensity | strength which the photocurable transfer sheet obtained can hold | maintain shape after hardening can be acquired. As mentioned above, the photopolymerization initiator is preferably in the range of 0.1 to 10% by mass.

  Since the photocurable transfer sheet of the present invention can be provided in the form of a film whose film thickness accuracy is precisely controlled, it is possible to easily and accurately bond the substrate and the stamper. In addition, this bonding can be carried out at 10 to 50 ° C. by a simple method such as a pressure roll or a simple press, and then cured by light at room temperature for 1 to several tens of seconds. Since it is difficult for displacement and peeling to occur in the laminate, it has a feature that it can be handled freely until photocuring.

  When the photocurable transfer sheet of the present invention is cured, many light sources that emit light in the ultraviolet to visible region can be used as the light source, for example, ultrahigh pressure, high pressure, low pressure mercury lamp, chemical lamp, xenon lamp, halogen lamp, Mercury halogen. A lamp, a carbon arc lamp, an incandescent lamp, a laser beam, etc. are mentioned. The irradiation time cannot be determined unconditionally depending on the type of lamp and the intensity of the light source, but is about several seconds to several minutes.

  In order to accelerate curing, the laminate may be preheated to 30 to 80 ° C. and irradiated with ultraviolet rays.

  The obtained reflective layer on the uneven surface of the substrate of the present invention is formed by metal deposition (for example, sputtering, vacuum deposition, ion plating, etc.) of the reflective layer on the substrate. Examples of the metal include aluminum, gold, silver, and alloys thereof. The translucent reflective layer on the cured sheet is formed using silver or the like as a metal. That is, it is necessary to make the reflective layer have a lower reflectance than the reflective layer, and the components, film thickness, etc. are changed.

When an organic polymer film is pasted on the reflective layer of the cured sheet, an adhesive is applied on one side, and the other is stacked thereon and cured. When the adhesive is a UV curable resin, it is obtained by UV irradiation, and when it is a hot melt adhesive, it is obtained by applying and cooling under heating.
The optical information recording medium of the present invention is usually processed in a disk shape (generally having a through hole in the center) as described above, but it is continuously formed in a sheet shape and finally made into a disk shape. Good.

  The following examples further illustrate the present invention.

[Example 1]
<Preparation of photocurable transfer sheet>
(Production of reactive polymer)
Formula I
2-ethylhexyl methacrylate 70 parts by mass Methyl methacrylate 20 parts by mass 2-hydroxyethyl methacrylate 10 parts by mass Benzophenone 5 parts by mass Toluene 30 parts by mass Ethyl acetate 30 parts by mass

  The mixture having the above composition was heated to 60 ° C. with gentle stirring to initiate polymerization, and stirred at this temperature for 10 hours to obtain an acrylic resin having a hydroxyl group in the side chain. Thereafter, 5 parts by mass of Karenz MOI (2-isocyanatoethyl methacrylate; Showa Denko KK) was added and reacted at 50 ° C. with gentle stirring in a nitrogen atmosphere to have reactivity having a photopolymerizable functional group. Polymer solution 1 was obtained.

  The obtained reactive polymer had a Tg of 0 ° C. and a methacryloyl group in the side chain of 5 mol%.

Formula II
Reactive polymer solution 1 100 parts by mass Hexanediol diacrylate 30 parts by mass 1-hydroxycyclohexyl phenyl ketone 1 part by mass

  The mixture of the above composition was uniformly dissolved and applied on the entire surface of a release sheet (width 300 mm, length 1000 m, thickness 75 μm; trade name No. 23, manufactured by Fujimori Kogyo Co., Ltd.), and a dry thickness of 20 ± 2 μm. A photocurable transfer sheet was formed, and the same release sheet as above was attached to the opposite side of the sheet and rolled up into a roll to obtain a roll (0.5 m in diameter) of the photocurable transfer sheet.

[Comparative Example 1]
In Example 1, the roll of the photocurable transfer sheet was obtained similarly except not using the hexanediol diacrylate of the mixing | blending II.

[Comparative Example 2]
In Example 1, the roll of the photocurable transfer sheet was obtained similarly except having used 60 mass parts of hexanediol diacrylate of the mixing | blending II.

(1) Evaluation of photo-curable transfer sheet (1-1) Measurement of storage elastic modulus of transfer sheet The storage elastic modulus of the transfer layer of the transfer sheet obtained in Example 1 and Comparative Examples 1 and 2 is viscoelastic. Measurement was performed using Rheo Stress RS300 (manufactured by HAAKE) as a measuring device. At that time, using a parallel plate of φ = 20 mm, measurement was performed at a measurement thickness of 1 mm (transfer layer was thinned by pressing), a measurement temperature of 25 ° C., and frequencies of 0.01 Hz, 1 Hz, and 100 Hz.
(1-2) Thickness accuracy The thickness of the obtained photocurable transfer sheet was measured at 10 locations per 1 m ² , and the degree of thickness variation was measured. The case where the variation was within 5% was rated as ◯, and the case where the variation was over 5% was marked as x.

(2) Evaluation of the obtained optical information recording medium After punching the roll of the photocurable transfer sheet of each example into a disk shape, one release sheet is removed, and the obtained disk-shaped photocurable transfer sheet is injected. On the aluminum reflective layer (70 nm) provided on the uneven surface of the polycarbonate substrate (thickness 1.1 mm) having an uneven surface as a pit formed by molding, the transfer sheet surface and the reflective layer are placed in contact with each other, The photocurable transfer sheet was pressed under a load of 2 kg using a roller made of silicone rubber having a surface temperature of 25 ° C. to form a laminate (corresponding to (3) in FIG. 2).

  Remove the other release sheet of the photo-curing transfer sheet of the laminate, and contact the surface of the removed transfer sheet with a nickel stamper with a concavo-convex surface as a pit, with the concavo-convex surface of the stamper The stamper was pressed with a load of 2 kg using a roller made of silicone rubber having a surface temperature of 25 ° C. to form a laminate, and the uneven shape of the stamper was transferred to the transfer sheet surface.

Next, UV irradiation was performed from the photocurable transfer sheet side using a metal halide lamp under conditions of an integrated light quantity of 1000 mJ / cm ² to cure the transfer sheet.

  The stamper was peeled and removed from the laminated body, and a silver alloy was sputtered onto the concavo-convex surface of the cured photocurable transfer sheet, thereby forming a silver alloy transflective layer. A polycarbonate film (thickness 70 μm; trade name Pure Ace C110-70, manufactured by Teijin Ltd.) was pasted thereon via an adhesive.

  Thus, an optical information recording medium having two layers of uneven surfaces was obtained.

(2-1) Light transmittance of the obtained optical information recording medium (wavelength region of 380 to 420 nm)
One photocurable transfer sheet was measured for light transmittance in a wavelength region of 380 to 420 nm in accordance with JIS-K6717. 70% or more was rated as ◯, and less than 70% as x.

(2-2) Transferability of the obtained optical information recording medium (signal reading)
The reproduction waveform of the obtained optical information recording medium was measured using a laser having a wavelength of 405 nm, and the transferability was evaluated by comparing the obtained reproduction waveform with the waveform of the stamper used for production. A mark that coincided with the waveform of the stamper was marked with ◯, and a mark that almost did not coincide was marked with x.

  The test results obtained are shown in Table 1.

  The photocurable transfer sheet obtained in Example 1 has good thickness accuracy and excellent workability, and the optical information recording medium obtained by using this has a good pit shape, and can be transferred at room temperature. It can be seen that it is excellent. On the other hand, the optical information recording medium produced from the photocurable transfer sheet having a storage modulus not using a diluent in Comparative Example 1 which is higher than the range of the present invention has a good thickness accuracy, but has a good transferability. Was inferior. Further, the optical information recording medium produced from a transfer sheet having a storage elastic modulus lower than the range of the present invention has good transferability but poor thickness accuracy.

Sectional drawing which shows an example of embodiment of the photocurable transfer sheet of this invention It is sectional drawing which shows an example of the manufacturing method of the optical information recording medium of this invention. It is sectional drawing which shows an example of the optical information recording medium of this invention. It is this schematic for demonstrating the press method using the apparatus of a double vacuum chamber system. It is sectional drawing which shows the conventional optical information recording medium. It is sectional drawing which shows another conventional optical information recording medium. It is sectional drawing which shows the procedure of the manufacturing method of the optical information recording medium as described in Nikkei Electronics.

Explanation of symbols

11 Photocurable transfer sheet 12a, 12b Release sheet 21 Substrate 23 Translucent reflective layer 24 Stamper 25 Reflective layer 26 Organic polymer film (cover layer)
1, 2 Transparent resin substrate 1a, 2a Reflective layer 3 Adhesive layer 1b Translucent layer 4a Disk substrate 5A, 5B UV curable resin 6a Reflective layer (or recording layer)
7 Cover layer

Claims (17)

It consists of a photocurable composition containing a reactive polymer having a photopolymerizable functional group, and the storage elastic modulus at frequencies of 1 Hz, 0.01 Hz, and 100 Hz is 1 × 10 ^{3 to} 9 × 10 ⁴ Pa at 25 ° C., respectively. The photocurable transfer sheet which has a photocurable transfer layer which is 5 * 10 < ³ > Pa or more and 1 * 10 < ⁷ > Pa or less.   The photocurable transfer sheet according to claim 1, wherein the photocurable composition further comprises a plasticizing reactive diluent having a photopolymerizable functional group having a molecular weight of 1000 or less.   The photocurable transfer sheet according to claim 2, wherein the photocurable composition contains a plasticizing reactive diluent in a solid content of 10% by mass or more.   The photocurable transfer sheet according to claim 2 or 3, wherein the plasticizing reactive diluent having a photopolymerizable functional group is di (meth) acrylate of alkanediol.   The photocurable transfer sheet according to claim 1, wherein the reactive polymer has a glass transition temperature of 20 ° C. or lower.   The photocurable transfer sheet according to any one of claims 1 to 5, wherein the number average molecular weight of the reactive polymer is 10,000 to 300,000.   The photocurable transfer sheet according to any one of claims 1 to 6, wherein the weight average molecular weight of the reactive polymer is 10,000 to 300,000.   The photocurable transfer sheet according to any one of claims 1 to 7, wherein the light transmittance in a wavelength region of 380 to 420 nm is 70% or more.   The photocurable transfer sheet according to any one of claims 1 to 8, wherein the light transmittance in a wavelength region of 380 to 800 nm is 70% or more.   The photocurable transfer sheet according to claim 1, wherein the photocurable transfer layer has a thickness of 5 to 300 μm.   The photocurable transfer sheet according to any one of claims 1 to 10, wherein a release sheet is provided on one or both surfaces of the photocurable transfer layer.   The photocurable transfer sheet according to claim 11, wherein the photocurable transfer sheet is long, and the photocurable transfer layer and the release sheet have substantially the same width. The following steps (2) to (4):
(2) The process of removing one peeling sheet of the photocurable transfer sheet of Claim 11 or 12;
(3) Photocuring of the photocurable transfer sheet on the reflective layer of the substrate having irregularities as recording pits and / or grooves on the surface and further provided with a reflective layer along the irregularities on the irregular surface. A laminate in which the surface of the light-sensitive transfer layer is placed in contact with the uneven surface of the reflective layer, and the surface of the photocurable transfer sheet is adhered along the uneven surface of the reflective layer by pressing them. Forming step;
The manufacturing method of the optical information recording medium characterized by the above-mentioned. Before the step (2),
(1) A step of punching a photocurable transfer sheet into a disc shape; or (1) A step of punching out the photocurable transfer layer of the photocurable transfer sheet and one release sheet into a disc shape, and leaving the other release sheet as it is. ;
The method of manufacturing an optical information recording medium according to claim 13. After performing the step (4), (5) the uneven surface of the stamper having unevenness as recording pits and / or grooves on the surface of the photocurable transfer layer from which the release sheet of the laminate has been removed. Placing and pressing them to form a laminate in which the surface of the photocurable transfer sheet is in close contact with the uneven surface;
(6) A step of providing irregularities on the surface of the photocurable transfer layer by curing the photocurable transfer layer of the laminate having the stamper by ultraviolet irradiation and then removing the stamper;
The method for producing an optical information recording medium according to claim 13 or 14, comprising: (7) A step of providing a reflective layer on the uneven surface of the photocurable transfer layer after performing the steps (5) to (6);
The method for producing an optical information recording medium according to claim 15, comprising: An optical information recording medium obtained by the production method according to claim 13.

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