JP2003263796A - Method for manufacturing optical information recording medium, and optical information recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an optical information recording medium in which superior recording characteristics and durability, and high productivity are available by using a method for manufacturing a cover layer in which a roll-like winding process is involved, and to provide the optical information recording medium. <P>SOLUTION: In the method for manufacturing the optical information recording medium, where the cover layers consisting of a cover film with an adhesive layer formed on the surface of a recording layer side provided on a substrate is laminated in such a way that the adhesive layer abuts on the surface, the cover layer is produced through: a process for forming a laminated body formed by successively laminating a first mold-released film, the adhesive layer, the cover film, and a second mold-released layer; and a process for winding the laminated body into a roll shape. In the first mold-released layer, its surface abutting on the surface of the adhesive layer has a center-surface average- roughness (SRa) of ≤50 nm and the other surface has a center-surface average- roughness (SRa) of ≤100 nm, and a thickness of ≥20 μm. The optical information recording medium is manufactured by the method. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a write-once type optical information recording medium capable of recording and reproducing by using a laser beam having a specific wavelength, and an optical information recording medium produced by the manufacturing method. .

[0002]

2. Description of the Related Art Conventionally, a write-once type optical information recording medium capable of recording information only once by laser light is widely known as CD-R. It has the advantage that it can be played back using a commercially available CD player, and recently, the demand thereof has increased with the spread of personal computers.
In addition, as a medium capable of recording a larger capacity than a CD-R,
A write-once digital versatile disc (DVD-
R) is also in practical use.

As one of the structures of these write-once type optical information recording media, a light-reflecting layer made of Au or the like, a recording layer made of an organic compound, and further adhered to the recording layer are formed on a disk-shaped substrate. It is known that the cover layer including the adhesive layer of 1) and the cover layer are sequentially laminated. Recording and reproduction can be performed by irradiating the laser beam from the resin layer side.
Recording of information on the write-once type optical information recording medium is performed by the laser light irradiation portion of the recording layer absorbing the light and locally deforming by heat generation (for example, generation of pits). On the other hand, in reproducing information, normally, a write-once type optical information recording medium is irradiated with a laser beam having the same wavelength as that of a recording laser beam, and a portion (recording portion) where the recording layer is heat-deformed and a portion where the recording layer is not deformed (recording portion) This is performed by detecting the difference in reflectance from the unrecorded portion).

Recently, networks such as the Internet and high-definition TV have been rapidly spread. Also, HDT
V (High Definition Televisions)
Ion) has also started airing. Under these circumstances,
There is a need for a large-capacity optical information recording medium capable of inexpensively and easily recording image information. The above-mentioned DVD-R plays a sufficient role as a large-capacity recording medium at present, but the demand for large-capacity and high-density recording is increasing, and it is necessary to develop a recording medium that can meet these demands. Is. Therefore, as for the optical information recording medium, further development of a recording medium having a larger capacity capable of performing high-density recording with light having a short wavelength is underway. Particularly, the write-once type optical information recording medium capable of recording information only once is being used more frequently for long-term storage or backup of large-capacity information, and therefore there is a strong demand for its development.

Generally, the high density of the optical information recording medium can be achieved by shortening the wavelength of the recording and reproducing laser and increasing the NA of the objective lens to reduce the beam spot. Recently, wavelengths of 680 nm, 650 nm and 6
Development is rapidly progressing from a 35 nm red semiconductor laser to a blue-violet semiconductor laser (hereinafter, referred to as a blue-violet laser) having a wavelength of 400 nm to 500 nm that enables ultra-high density recording, and optical information corresponding thereto is being developed. Recording media are also being developed. In particular, since the release of the blue-violet laser, development of an optical recording system using the blue-violet laser and a high NA pickup has been considered, and a rewritable optical information recording medium having a recording layer that changes in phase and an optical recording system have been developed. Already, DVR system ("ISOM2000" 210-2
11). As a result, a certain result was obtained with respect to the problem of high density in the rewritable optical information recording medium.

The optical information recording medium used in the optical recording system using the blue-violet laser and the high NA pickup as described above has a high NA when the recording layer is irradiated with the blue-violet laser light.
In order to adjust the focus of the objective lens, it is preferable to thin the cover layer on which the laser light is incident. Here, for example, a thin film is used as the cover layer, and the cover layer is adhered to the recording layer using an adhesive or a pressure-sensitive adhesive. The thickness of the cover layer is usually about 100 μm including the adhesive layer formed by curing the adhesive, but it is optimized depending on the wavelength of the laser to be irradiated and NA.

Further, in Japanese Patent Laid-Open No. 2000-67468, a film laminate having a structure in which a laminate of a transparent film and an adhesive sheet is sandwiched between release films is continuously formed, and then formed into a disc shape. Processing into a disc-shaped film laminate, further peeling the release film on the side in contact with the pressure-sensitive adhesive sheet, while sticking while aligning on the optical disk substrate surface on which the recording surface is formed,
The method of providing the cover layer by this method is described.
According to this method, after continuously forming the film laminate, when the film laminate is wound into a roll,
If the surface shape of the release film is transferred to the adhesive surface of the adhesive sheet and the surface roughness of the release film is large,
The surface roughness of the adhesive surface also becomes large, the optical information recording medium provided with the cover layer using the adhesive sheet, surface blurring and thickness unevenness occur, or bubbles are mixed, as a result,
It was not possible to obtain sufficient recording characteristics and durability.

[0008]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide excellent recording characteristics and durability in a method for producing an optical information recording medium using a method for producing a cover layer having a step of winding in a roll shape. To provide a method of manufacturing an optical information recording medium having properties, and an optical information recording medium manufactured by the manufacturing method. Another object of the present invention is to provide a method of manufacturing an optical information recording medium having excellent productivity, and an optical information recording medium manufactured by the manufacturing method.

[0009]

Means for Solving the Problems The present inventor suppresses the transfer of the surface shape of the release film to the adhesive layer in the step of winding the cover layer sandwiched by the release film in a roll shape. By doing so, it has been found that the problems of the above-mentioned conventional techniques can be solved by increasing the adhesiveness of the adhesive layer, and the present invention has been completed. That is, the method for producing an optical information recording medium of the present invention, on the surface of the recording layer side provided on the substrate,
A method of manufacturing an optical information recording medium, comprising a cover layer comprising a cover film provided with an adhesive layer, the adhesive layer being attached so that the adhesive layer contacts the surface, and the cover layer comprises a first release layer. A film, an adhesive layer, a cover film, and a second release film are sequentially laminated, to form a laminate, and a step of winding the laminate into a roll, The center surface average roughness (SRa) of the surface of the first release film in contact with the surface of the adhesive layer
Is 50 nm or less, the center surface average roughness (SRa) of the other surface
Is 100 nm or less and the thickness is 20 μm or more.

In the method for producing an optical information recording medium of the present invention, after the step of winding the laminated body into a roll, a step of holding the adhesive layer until the crosslinking reaction is substantially completed, and the laminated layer. Sequentially performing a step of punching the body into a disk shape, a step of stacking and holding the disk-shaped laminated body substantially vertically or substantially horizontally, and a step of peeling the first and second release films. Is preferred. The optical information recording medium of the present invention is characterized by being manufactured by the method for manufacturing the optical information recording medium.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The method for manufacturing the optical information recording medium of the present invention will be described in detail below. First, a characteristic method of manufacturing the cover layer in the method of manufacturing the optical information recording medium of the present invention will be described. In the present invention, the cover layer includes at least (a) a step of forming a laminate in which a first release film, an adhesive layer, a cover film, and a second release film are sequentially laminated. , (B) a step of winding the laminated body in a roll shape, and then manufactured. Hereinafter, each step will be described.

[(A) Step of forming a laminated body in which a first release film, an adhesive layer, a cover film and a second release film are sequentially laminated] This step is formed. The laminated body 100 has an adhesive layer 2 as shown in FIG.
The cover film 10 provided with 0 has a structure in which both surfaces are sandwiched between the first release film 30 and the second release film 40. Here, FIG. 1 is a schematic sectional view for explaining the structure of the laminated body. In the step (a), the first release film 30 used is to be attached to the surface (adhesive surface) of the adhesive layer, and has a center plane average roughness (of the surface A that contacts the surface of the adhesive layer ( SRa) is 50 nm or less, and the center surface average roughness (SRa) of the other surface B is
Is 100 nm or less and the thickness is 20 μm or more. More preferably, the center plane average roughness of surface A (SRa)
Of 40 nm or less and the center plane average roughness (SRa) of the surface B is 8
It is particularly preferable that the thickness is 0 nm or less and the thickness is 25 μm or more, the center surface average roughness (SRa) of the surface A is 30 nm or less, the center surface average roughness (SRa) of the surface B is 60 nm or less, and the thickness is 30 μm or more. . Here, the center surface average roughness (SR
a) means that the orthogonal coordinate axes X and Y are placed on the center plane of the roughness curved surface, the axis orthogonal to the center plane is the Z axis, and the roughness curved surface is f.
It is a value calculated as (x, y) and the sizes Lx and Ly of the reference surface.

By thus defining the surface roughness of the surface A of the first release film 30 within the above range, the surface roughness of the surface A of the first release film 30 is directly determined by the adhesive layer. It is possible to prevent the transfer. Further, by defining the surface roughness and the thickness of the surface B of the first release film 30, the surface roughness of the surface B of the first release film 30 and the surface roughness of the second release film 40 are defined. Can indirectly reduce the influence on the surface roughness of the adhesive layer. Therefore, the optical information recording medium of the present invention prevents occurrence of surface wobbling and thickness unevenness due to the surface roughness of the adhesive layer, and has good adhesiveness, resulting in sufficient It has the effect of obtaining recording characteristics and durability.

On the other hand, in the step (a), the second release film 40 used is attached to the surface of the cover film via a thin adhesive layer or adhesive layer (not shown). Usually, the cover film 10 used for the cover layer has the following properties in order to prevent scattering of irradiated light.
Surface smoothness is required, but if the surface smoothness is high,
When wound in a roll shape, it often causes disorder of winding and poor handling in slits and punching steps. Therefore, the second release film 40 having a large surface roughness on the surface D is attached to the surface of the cover film 10 to impart a handling characteristic of facilitating winding. In addition, the second release film 40 preferably has a smooth surface C in order to improve the adhesion with the cover film 10. Specifically, in the second release film 40, the center surface average roughness (SRa) of the surface C in contact with the cover film is 50 nm or less, and the center surface average roughness (SRa) of the other surface D is 200 n.
It is preferably m or more. Also, the thickness is 10 to 100
It is preferably μm.

As the first release film 30 and the second release film 40, polyethylene film, polypropylene film, polyethylene terephthalate film, vinyl chloride film, vinylidene chloride film can be preferably used. In order to obtain the desired surface roughness as described above with these films, conventionally known methods can be used. Specifically, the film formation conditions (stretching degree, speed), It can be appropriately adjusted depending on the amount, size and shape of the filler contained.

The method of providing the adhesive layer 20 on the surface of the cover film 10 is not particularly limited, but it is used because there is a step of winding the laminate 100 in a roll in (b) described later. The cover film 10 preferably has a continuous length such that it can be wound into a roll, and an adhesive layer is preferably continuously provided on the surface of the cover film. Specifically, a method of pasting a pressure-sensitive adhesive layer 20 formed in advance on the surface of the cover film 10 (hereinafter, appropriately referred to as an indirect method) and a method of directly applying a pressure-sensitive adhesive to the surface of the cover film 10, A method of forming the adhesive layer 20 by drying (hereinafter, appropriately referred to as a direct method) can be roughly classified into two. Alternatively, a commercially available adhesive film provided with the adhesive layer 20 in advance may be used.

In the case of the indirect method, for example, the adhesive layer can be continuously attached to the surface of the cover film via an adhesive layer installation device as shown in FIG. Here, FIG. 2 is a schematic cross-sectional view of an adhesive layer installation device used in an exemplary embodiment of a method for continuously providing an adhesive layer on the surface of a cover film. In addition, such an adhesive layer installation device, in the device,
The step (b) of winding the laminated body 100 into a roll described below can also be performed. As shown in FIG. 2, the pressure-sensitive adhesive layer installation device is a roll 1 around which a release film f ₁ is wound.
Coating means 2, drying means 3 and cover film f ₂
It has a roll 4 around which the (cover film 10) is wound, and a roll 5 around which the release film f ₁ provided with an adhesive layer and the cover film f ₂ are wound together.

[0018] The operation of the pressure-sensitive adhesive layer installation apparatus, first, a release film f ₁ from the roll 1 wound, feed the release film f ₁ in the direction of the arrow. The control unit (not shown)
When it is confirmed that the tip of the released release film f ₁ has been conveyed to a predetermined area (application area), the surface of the release film f ₁ is preliminarily formed on the surface of the release film f ₁ by using the application unit 2 installed in the area. The application of the prepared adhesive coating solution is started (application step). By such a coating process, the release film f ₁ having the pressure-sensitive adhesive coating layer is obtained. The adhesive coating process is continued until the release film f ₁ wound around the roll 1 is fed to the end. When a control unit (not shown) confirms that the release film f ₁ on which the pressure-sensitive adhesive coating layer is formed has been conveyed to the drying area, the pressure-sensitive adhesive coating layer is dried by the drying means 3 installed in the drying area. (Drying process). Then, in this step, the solvent of the pressure-sensitive adhesive coating layer is volatilized, and the release film f ₁ provided with the pressure-sensitive adhesive layer is obtained. After that, the release film f ₁ provided with an adhesive layer is further conveyed, and the cover film f ₂ delivered from the roll 4 and the surface of the cover film f ₂ and the adhesive layer contact each other in the bonding area a. As in (bonding step). Then, the release film f ₁ provided with an adhesive layer and the cover film f ₂ are wound together on the roll 5 (winding step). In the adhesive layer installation device,
These series of steps are performed by one roll-shaped release film f.
₁ is sent out from the roll 1 and continuously performed until it is wound up on the roll 5.

In the adhesive layer installation device, as the coating means 2, a conventionally known coating means can be used. Specific examples thereof include a spraying method, a roll coating method, a blade coating method, a doctor roll method, and a screen printing method. Further, as the drying means 3, conventionally known coating means such as heat drying and blast drying can be used.

The release film f ₁ used in the adhesive layer installation device in the indirect method has the same surface properties and thickness as the above-mentioned first release film 30, and the first release film is used as it is. It may be made to function as the film 30, or the release film f ₁ may be peeled off before being wound up on the roll 5, and the first release film 30 may be newly attached. In addition, the second release film 40 may be provided in advance on the surface of the cover film f ₂ used in the adhesive layer installation device in the indirect method where the adhesive layer is not provided, or the roll 5 may be provided with the second release film 40. The second release film 30 may be attached before being wound up. Further, as the roll-shaped cover film f ₂ , for example, 75 m
A film having a width of 130 mm and a length of 200 m wound around an mφ axis can be used.

Here, when the step (a) and the step (b) described later are continuously performed in the above-mentioned indirect method pressure-sensitive adhesive layer installation device, the release film f ₁ is left as it is. It is preferable that the second release film 40 is provided in advance on the surface of the cover film f _{2 on which} the adhesive layer is not provided, using the one that functions as the first release film 30.

In the case of the direct method, a roll-shaped cover film is sent out, the adhesive coating solution is continuously applied from the front end to the end of the cover film to form an adhesive coating layer, and then the adhesive coating is sequentially applied. The layer is dried to form an adhesive layer over the entire surface on one side of the cover film. After that, the first release film 30 is adhered to the surface of the adhesive layer (adhesive surface), and the second release film 40 is adhered to the surface of the cover film to form the laminate 100. Also in the coating and drying steps in the direct method, the same means as the coating means and the drying means used in the adhesive layer installation device can be used.

The cover film 10 (cover film f ₂ ) used in the step (a) is not particularly limited as long as it is a film made of a transparent material, but an acrylic resin such as polycarbonate or polymethylmethacrylate;
It is preferable to use vinyl chloride resins such as polyvinyl chloride and vinyl chloride copolymers; epoxy resins; amorphous polyolefins; polyesters; cellulose triacetate, and more preferably polycarbonate or cellulose triacetate. The term "transparent" means that the transmittance of light used for recording and reproduction is 80%.
It means that it is more than%.

Further, the cover film 10 may contain various additives as long as the effects of the present invention are not impaired. For example, a UV absorber for cutting light having a wavelength of 400 nm or less and / or a dye for cutting light having a wavelength of 500 nm or more may be contained. As for the surface physical properties of the cover film 10, it is preferable that the surface roughness is 5 nm or less for both the two-dimensional roughness parameter and the three-dimensional roughness parameter. Further, from the viewpoint of the degree of condensing light used for recording and reproduction, the cover film 1
The birefringence of 0 is preferably 10 nm or less.

The cover film 10 has a thickness of 0.03 to
The range of 0.15 mm is preferable, and 0.05 to
The range of 0.12 mm is more preferable. With such a range, there is an advantage that handling in the step of attaching the cover film 10 becomes easy and coma aberration can be suppressed.

As the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer formed in the step (a), acrylic-based, rubber-based or silicon-based pressure-sensitive adhesives can be used, but transparency,
From the viewpoint of durability, acrylic adhesives are preferable. As such an acrylic pressure-sensitive adhesive, 2-ethylhexyl acrylate, n-butyl acrylate or the like is a main component, and in order to improve cohesive force, a short chain alkyl acrylate or methacrylate, for example, methyl acrylate, ethyl acrylate, methyl methacrylate. And acrylic acid, methacrylic acid, which can be a cross-linking point with the cross-linking agent,
It is preferable to use a copolymerized product of an acrylamide derivative, maleic acid, hydroxylethyl acrylate, glycidyl acrylate and the like. A mixing ratio of the main component, the short chain component, and the component for adding a crosslinking point,
The glass transition temperature (Tg) and the crosslink density can be changed by appropriately adjusting the type.

A cross-linking agent is preferably mixed with the above-mentioned pressure-sensitive adhesive in order to improve the tackiness and durability. Examples of such a crosslinking agent include an isocyanate crosslinking agent, an epoxy resin crosslinking agent, a melamine resin crosslinking agent, a urea resin crosslinking agent, and a chelate crosslinking agent.
Isocyanate crosslinking agents are more preferred. Examples of the isocyanate cross-linking agent include tolylene diisocyanate, 4-4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, naphthylene-1,5-diisocyanate, o-
Isocyanates such as toluidine isocyanate, isophorone diisocyanate and triphenylmethane triisocyanate, products of these isocyanates with polyalcohols, and polyisocyanates produced by condensation of isocyanates can be used. Commercially available products of these isocyanates are Nippon Polyurethane Co., Ltd., Coronate L, Coronate HL, Coronate 2030, Coronate 203.
1. Millionate MR, Millionate HTL; Takenate D-102, Takenate D-110 manufactured by Takeda Pharmaceutical Co., Ltd.
N, Takenate D-200, Takenate D-202; Sumitomo Bayer, Death Module L, Death Module I
L, death module N, death module HL; and the like.

[(B) Step of winding the laminated body into a roll] In the step (a), the first release film 30 is formed on the laminated body 100 formed by the direct method or on a commercially available adhesive sheet. In this step, the laminate 100 formed by sticking the second release film 40 to each other is wound into a roll, so that the laminate 100 is more portable than a plate-like laminate having the same amount. It has the advantage of being easy and having excellent transportability. Further, the adhesive layer installation device continuously performs the steps (a) and (b), and the formed laminate 100 is easily removed from the device and easily transferred to other steps described below. can do.

[Other Steps for Producing Cover Layer] (Keeping until the crosslinking reaction of the adhesive layer is substantially completed)
This step is a step for improving the durability of the optical information recording medium by making the adhesiveness of the adhesive layer and the adhesiveness with the bonding surface of the recording layer or the intermediate layer excellent. In this step, the laminate 100 wound into a roll in the step (b) is held until the crosslinking reaction of the adhesive layer is substantially completed. Here, "until the crosslinking reaction of the pressure-sensitive adhesive layer is substantially completed" means "the pressure-sensitive adhesive layer is measured by an infrared absorption spectrum, and a peak derived from a functional group involved in the crosslinking of the crosslinking agent used is substantially Until it disappears "
Refers to the thickness of the pressure-sensitive adhesive layer, the type of pressure-sensitive adhesive that constitutes the pressure-sensitive adhesive layer, the type of cross-linking agent, and the atmosphere (temperature and humidity) of the space where
Is adjusted accordingly.

For example, an acrylic adhesive as the adhesive
And an isocyanate cross-linking agent as a cross-linking agent,
The composed adhesive layer (X) has a temperature of 23 ° C. and a humidity of 50% R
In an atmosphere of h, the infrared absorption spectrum of the adhesive layer is
Measure the vector over time, and check it before holding (immediately after application).
2275 to 2250 cm derived from isocyanate
^-1Until the absorption peak that appears in the vicinity disappears
By measuring the time, the "crosslinking reaction of the adhesive layer (X) was confirmed.
It is possible to find the time corresponding to "until qualitatively ends"
Wear. Thus, the "crosslinking reaction of the adhesive layer
The time corresponding to "until practically ended" is
Is a normal room temperature environment (temperature 21 to 30 ° C., humidity 30 to 8
72 hours at 0% Rh). For this reason,
Cover film provided with an adhesive layer in an environment
Must be held for 72 hours or more.

(Step of punching the laminated body into a disk shape) In this step, the laminated body 100 has a predetermined size, that is,
It is punched into a disk having the same size as the substrate described later. More specifically, the stacked body 100 is sent out, and is temporarily flattened, and is continuously punched into the same size as the substrate by using, for example, a cut punch.
After that, the stacked body 100 other than the punched portion is wound into a roll shape again, so that the dust generated by the punching can be easily collected.

(Step of Stacking and Holding Disk-shaped Laminates in a Vertical or Horizontal Alignment) This step is for correcting distortions such as curl, curl, and anisotropy generated in the laminate 100. Done. As a method of stacking and holding the disc-shaped laminated body 100, for example, the disc-shaped laminated body 100 is held in a state of being laminated substantially vertically, and a load is applied to the laminated body 100 in the same vertical direction to cause strain. Can be corrected. Alternatively, the strain may be corrected by holding the stacked body 100 in a state of being stacked substantially horizontally and applying its own weight or a load in the direction of gravity.

In this state, for a predetermined time, for example, 1 hour,
By holding the disc-shaped laminated body 100, distortions such as curl, curl, and anisotropy are corrected. The holding time is appropriately set depending on the thickness of the cover film, the thickness of the pressure-sensitive adhesive layer, the types of pressure-sensitive adhesives that form the pressure-sensitive adhesive layer, crosslinking agents and other additives, and the atmosphere (temperature and humidity) of the space to be held. Adjusted.

As described above, according to the present invention, since the cover layer has a small surface roughness, it has an excellent effect that uneven thickness and inclusion of bubbles are small. In addition, all the steps of forming the cover layer are continuously performed, and as described above, they have excellent transportability and easy collection of dust, and thus have an effect of excellent productivity. Furthermore, in addition to the above effects, the cover layer produced through the above-described various steps exhibits high adhesion to the bonding surface of the recording layer or the intermediate layer, and exhibits curl, curl, anisotropy, and the like. Since the distortion is corrected, it is possible to further reduce the occurrence of surface unevenness and thickness unevenness. The cover layer peels off the first release film, and is adhered to the surface of the recording layer provided on the substrate so that the adhesive layer contacts the surface, and then the second release film is peeled off. By doing so, an optical information recording medium is manufactured.
The optical information recording medium manufactured in this manner has excellent recording characteristics and durability.

Here, in the method for manufacturing an optical information recording medium of the present invention, in addition to the step of forming the cover layer, a light reflecting layer forming step for forming the light reflecting layer on a substrate, which will be described later, There are various known steps including a recording layer forming step of forming the recording layer on the light reflecting layer.

<Light-Reflecting Layer Forming Step> The light-reflecting layer forming step is a step of forming a light-reflecting layer made of a light-reflecting substance on the surface of the substrate, which will be described later, on which the pre-groove is formed. As the substrate, various materials used as the substrate material of the conventional optical information recording medium can be arbitrarily selected and used. Specifically, glass; polycarbonate,
Acrylic resins such as polymethylmethacrylate; vinyl chloride resins such as polyvinyl chloride and vinyl chloride copolymer; epoxy resins; amorphous polyolefins; polyesters; metals such as aluminum; and the like. May be. Among the above materials,
From the viewpoint of moisture resistance, dimensional stability and low cost, amorphous polyolefin and polycarbonate are preferable, and polycarbonate is particularly preferable. The thickness of the substrate is
It is preferably 1.1 ± 0.3 mm.

A guide groove for tracking or unevenness (pre-groove) representing information such as an address signal is formed on the substrate. In order to achieve a higher recording density, a pre-groove with a narrower track pitch is required as compared with CD-R and DVD-R. For example, DVR-bl
When used as a medium such as ue, it is essential that the track pitch of the pre-groove is in the range of 200 to 400 nm, preferably 250 to 350 nm.
It becomes the range of. Also, the depth of the pre-groove (groove depth)
Must be in the range of 20 to 150 nm, and is preferably in the range of 50 to 100 nm.

For the purpose of improving the flatness and the adhesive force, the substrate surface on the side where a light reflecting layer described later is provided is
It is preferable to form an undercoat layer. Examples of the material for the undercoat layer include polymethylmethacrylate, acrylic acid / methacrylic acid copolymer, styrene / maleic anhydride copolymer, polyvinyl alcohol, N-methylolacrylamide, styrene / vinyltoluene copolymer, and chloro. Polymeric substances such as sulfonated polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, vinyl acetate / vinyl chloride copolymer, ethylene / vinyl acetate copolymer, polyethylene, polypropylene, polycarbonate; silane coupling Surface modifiers such as agents. The undercoat layer is prepared by dissolving or dispersing the above materials in a suitable solvent to prepare a coating liquid, and then spin coating, dip coating,
It can be formed by coating the substrate surface by a coating method such as extrusion coating. The thickness of the undercoat layer is generally in the range of 0.005 to 20 μm, preferably 0.01 to 10 μm.

The light reflecting layer can be formed on the substrate by vapor deposition, sputtering or ion plating of a light reflecting substance having a high reflectance for laser light. The thickness of the light reflecting layer is generally 10 to 300 nm.
And the range of 50 to 200 nm is preferable. The reflectance is preferably 70% or more.

As the light-reflecting substance having a high reflectance, M
g, Se, Y, Ti, Zr, Hf, V, Nb, Ta, C
r, Mo, W, Mn, Re, Fe, Co, Ni, Ru,
Rh, Pd, Ir, Pt, Cu, Ag, Au, Zn, C
d, Al, Ga, In, Si, Ge, Te, Pb, P
Examples thereof include metals such as o, Sn, and Bi, semimetals, and stainless steel. These light-reflecting substances may be used alone, in a combination of two or more, or as an alloy. Preferred among these are Cr, Ni, Pt, Cu, Ag, Au, Al and stainless steel. Particularly preferably Au, A
g, Al or alloys thereof, most preferably Au, Ag or alloys thereof.

<Recording Layer Forming Step> The recording layer forming step is a step of forming a recording layer on the light reflecting layer. The recording layer is capable of recording information with a laser beam having a wavelength of 600 nm or less, and preferably contains a dye as a recording substance. Examples of the dye contained in the recording layer include a cyanine dye, an oxonol dye, a metal complex dye, an azo dye, and a phthalocyanine dye.

Further, JP-A-4-74690, JP-A-8-127174, JP-A-11-53758, JP-A-11-334204, and JP-A-11-33420.
5 publication, 11-334206 publication, 11-33 publication.
4207, JP-A-2000-43423, JP-A-2000-108513, and JP-A-2000-1.
The dyes described in Japanese Patent No. 58818 and the like are also preferably used.

For the recording layer, a recording material such as a dye is dissolved in a suitable solvent together with a binder and the like to prepare a coating liquid, and then the coating liquid is coated on the light reflecting layer formed on the surface of the substrate. It is formed by forming a coating film and then drying it. The concentration of the recording substance in the coating liquid is generally in the range of 0.01 to 15% by mass, preferably 0.1 to 10% by mass, more preferably 0.5 to 5% by mass, and most preferably Is in the range of 0.5 to 3 mass%.

Solvents for the coating liquid include butyl acetate, ethyl lactate, cellosolve acetate, etc .; methyl ethyl ketone, cyclohexanone, methyl isobutyl ketone, etc. ketone; chlorinated hydrocarbons such as dichloromethane, 1,2-dichloroethane, chloroform; dimethyl. Amides such as formamide; hydrocarbons such as methylcyclohexane; ethers such as tetrahydrofuran, ethyl ether, dioxane; alcohols such as ethanol, n-propanol, isopropanol, n-butanol diacetone alcohol; 2,2,3,3-tetrafluoro Fluorine-based solvents such as propanol; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether; Rukoto can. The above solvents can be used alone or in combination of two or more in consideration of the solubility of the recording substance to be used. Various additives such as an antioxidant, a UV absorber, a plasticizer and a lubricant may be added to the coating liquid depending on the purpose.

When a binder is used, examples of the binder include gelatin, cellulose derivatives, dextran,
Natural organic high molecular substances such as rosin and rubber; polyethylene,
Hydrocarbon resin such as polypropylene, polystyrene, polyisobutylene, vinyl resin such as polyvinyl chloride, polyvinylidene chloride, polyvinyl chloride / polyvinyl acetate copolymer, acrylic resin such as polymethyl acrylate and polymethyl methacrylate. , Polyvinyl alcohol, chlorinated polyethylene, epoxy resins, butyral resins, rubber derivatives, synthetic organic polymers such as initial condensates of thermosetting resins such as phenol / formaldehyde resins; When using a binder as the material of the recording layer,
The amount of the binder used is generally in the range of 0.01 times to 50 times the mass (mass ratio) of the recording substance, preferably 0.
It is in the range of 1-fold amount to 5-fold amount (mass ratio). The concentration of the recording substance in the coating liquid thus prepared is generally 0.
It is in the range of 01 to 10% by mass, preferably 0.1 to 5
It is in the range of mass%.

Examples of the coating method include spraying method, spin coating method, dipping method, roll coating method, blade coating method, doctor roll method and screen printing method. The recording layer may be a single layer or multiple layers. The layer thickness of the recording layer is generally in the range of 20 to 500 nm,
It is preferably in the range of 30 to 300 nm, more preferably in the range of 50 to 100 nm. Further, the coating liquid temperature is preferably in the range of 23 to 50 ° C., and 24 to
It is more preferably in the range of 40 ° C., especially 23
It is particularly preferably in the range of -50 ° C.

The recording layer may contain various anti-fading agents in order to improve the light resistance of the recording layer. A singlet oxygen quencher is generally used as the anti-fading agent. As a singlet oxygen quencher,
Those described in publications such as already known patent specifications can be used. As a specific example thereof, there is JP-A-58-1.
No. 75693, No. 59-81194, and No. 60.
No. 18387, No. 60-19586, and No. 6
0-19587, 60-35054, 60-36190, 60-36191,
No. 60-44554, No. 60-44555, No. 60-44389, No. 60-44390, No. 60-54892, No. 60-47069.
Japanese Patent Publication No. 63-209995, Japanese Patent Laid-Open No. 4-25
Japanese Patent Publication No. 492, Japanese Patent Publication No. 1-386080, and Japanese Patent Publication No. 6-26028, and German Patent 3503.
No. 99, and those described in the Chemical Society of Japan, October 1992, page 1141 and the like.

The amount of the anti-fading agent such as the singlet oxygen quencher used is usually in the range of 0.1 to 50% by mass, preferably 0.5 to 45% by mass, based on the amount of the dye. The range is more preferably 3 to 40% by mass, and particularly preferably 5 to 25% by mass.

<Intermediate Layer Forming Step> In the method for producing an optical information recording medium of the present invention, an intermediate layer may be provided on the recording layer. The intermediate layer is provided to enhance the storage stability of the recording layer and improve the adhesiveness between the recording layer and the cover layer. The material used for the intermediate layer is not particularly limited as long as it is a material that transmits light used for recording and reproduction, but, for example, a dielectric is generally preferable. Specifically, Zn, Si, Ti, T
Materials composed of nitrides, oxides, carbides, and sulfides such as e, Sn, Mo, and Ge are preferable, and ZnS, MoO ₂ , Ge
_{O 2, TeO, SiO 2,} TiO 2, ZuO, ZnS-S
iO ₂ and SnO ₂ are preferable, and ZnS—SiO ₂ and SnO ₂
Is more preferable. Moreover, this intermediate layer can be formed by vacuum film formation such as vapor deposition and sputtering.

As described above, the disk laminate formed through the light reflecting layer forming step, the recording layer forming step, and the intermediate layer forming step if necessary, and the cover layer forming step described above are prepared. An optical information recording medium is obtained by bonding the cover layer thus formed to the optical information recording medium.

The present invention has been described above with reference to an example of a method for producing an optical information recording medium provided with a recording layer containing an organic compound such as a dye as a recording substance.
A phase change recording layer for recording by phase change or a magneto-optical recording layer for recording by magneto-optical may be used. For example, in the case of a phase-change recording layer, the dielectric layer is composed of ZnS-SiO ₂ or the like, a dielectric layer provided instead of the light transmission layer. The phase change recording layer contains Sb, Te, A as a recording material.
A metal compound such as chalcogenide such as g or In can be used.

[0052]

EXAMPLES The present invention will be described in more detail below with reference to Examples, but the present invention is not limited thereto.

Example 1 <Production of Optical Information Recording Medium> Spiral groove (depth 100 nm, width 120 nm, track pitch 320 n)
m), 1.1 mm thick, 120 mm diameter injection molded polycarbonate resin (polycarbonate manufactured by Teijin Ltd.,
Product name: Panlite AD5503) Ag was sputtered on the grooved surface of the substrate to form a light-reflecting layer having a thickness of 100 nm (light-reflecting layer forming step).

After that, Orazol GN (phthalocyanine)
Nin-based dye, manufactured by ciba Specialty Chemicals Co., Ltd. 2
0 g of 2,2,3,3-tetrafluoropropanol 1
Add to liter and sonicate for 2 hours to dissolve
Then, a coating liquid for forming the recording layer was prepared. Prepared application
The liquid is spun on the light reflection layer at a rotation speed of 300 to 4000 rpm.
While changing the temperature to 23 ° C and 50% RH,
It was applied by pin coating. After that, 23 ℃, 50% R
The thickness of the recording layer formed by storing it in H for 1 to 4 hours 100
nm (recording layer forming step). And on the recording layer
ZnS-SiO ₂To a thickness of 5 nm
To form an intermediate layer.

<Preparation of Cover Layer> [Preparation of Adhesive Coating Solution] Acrylic copolymer (solvent: ethyl acetate / toluene = 1/1) and isocyanate cross-linking agent (solvent: ethyl acetate / toluene = 1/1) 1) and 1
The mixture was mixed at a ratio of 00: 1 (mass ratio) to prepare an adhesive coating liquid A.

[Surface Roughness and Thickness of First Release Film] The center surface average roughness (SRa) of the first release film used in this example was measured by the following method. Device: WYKO HD-2000 type objective lens: x50, intermediate lens: x0.5 Measurement range: 242 μm x 184 μm After performing inclination correction and cylindrical correction on the data, the center surface average roughness (SRa) is measured. did. The measurement results are shown in Table 1. In addition, Table 1 also shows the thickness of the first release film.

[(A) a step of forming a laminated body in which a first release film, an adhesive layer, a cover film and a second release film are sequentially laminated, and (b) a laminated body Step of winding into a roll] First, an adhesive layer was provided on the surface of the cover film using the adhesive layer installation device shown in FIG. Specifically, the first release film (polyethylene release film) wound on the roll 1 is fed in the direction of the arrow, and the application unit 2 installed is used to adhere to the surface of the first release film. The agent coating solution A was applied (application step). Then, the first release film on which the adhesive coating layer is formed,
Drying at 100 ° C. by a drying means 3 installed in a drying area (drying step), and a first adhesive layer having a film thickness of 20 μm
To obtain a release film. Then, the cover film (polycarbonate film, Teijin Pure Ace, thickness: 80 μm, with a second release film on one side, which was further fed with the first release film provided with an adhesive layer and sent out from the roll 4; The surface roughness of the surface D of the second release film, 250
nm) and the bonding area a so that the polycarbonate surface of the cover film and the adhesive layer contact each other (bonding step). As a result, a laminate in which the first release film, the adhesive layer, the cover film, and the second release film were sequentially laminated was obtained. Then, the laminate was wound around the roll 5 (winding step).

[Step of holding until the crosslinking reaction of the pressure-sensitive adhesive layer is substantially completed] The wound laminate was heated at 23 ° C. and 50% R
The atmosphere of h was maintained for 72 hours. The term "72 hours" means that the pressure-sensitive adhesive layer in this example is measured with an infrared spectroscopic absorption spectrum over time in the atmosphere, and an absorption peak appearing near 2275 to 2250 cm ^-1 derived from isocyanate is substantially present. It is the elapsed time until it disappears, and is the time corresponding to "until the crosslinking reaction of the adhesive layer is substantially completed" in this example.

After that, the laminated body was punched into the same shape (disk shape) as the above substrate. Then, in the disc-shaped laminated body, first, the first release film was peeled off, and the intermediate layer and the adhesive layer were attached to each other by a pressing means using a roller. Further, the second release film was peeled off to obtain the optical information recording medium in Example 1.

<Evaluation> (1) C / N (Carrier to Noise Ratio) The produced optical information recording medium was used as a laser for 405 nm and N
A: A recording / reproducing evaluation device (DDU1000 manufactured by Pulstec Co., Ltd.) equipped with a 0.85 pickup was used, and a single frequency signal (2T = 0.13 μm) under the condition of a clock frequency of 66 MHz / linear velocity of 5.6 m / s. ) Was recorded and reproduced, and C / N was measured using a spectrum analyzer.
The results are shown in Table 1.

(2) Evaluation of Cover Layer Thickness Unevenness The optical information recording medium prepared was measured by a Keyence laser displacement meter (LT8020) to measure the cover layer thickness as a sheet distance between two points. 8 points in the circumferential direction of the medium (45 ° intervals), 8 points in the radial direction (5 mm intervals), total 6
The measurement was carried out at 4 points, and the thickness unevenness was determined from the (maximum value-minimum value / average value). As a criterion for judgment, those with 2% or less were evaluated as ◯ (no practical problems), and those with more than 2% were evaluated as x (no practical use). The results are shown in Table 1.

(3) Evaluation of Bubble Inclusion The produced optical information recording medium was measured from the cover layer side with a telecentric microscope (manufactured by Kowa Co., Ltd.) in a measuring range of 4.8 mm × 6.4 mm at about 40 times, 10 fields of view. Observation was performed to observe the mixing ratio of bubbles. As a criterion for judgment, the number of bubbles is 0 in the average value. ○, 1 to 5
The number of pieces was Δ, and the number of 6 or more was x. The results are shown in Table 1.

[Examples 2 to 5] In the step of producing the cover layer of Example 1, except that the first release film was replaced with one having the surface roughness and the thickness shown in Table 1, respectively.
Optical information recording media of Examples 2 to 5 were manufactured in the same manner as in Example 1. The manufactured optical information recording medium was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Examples 1 to 4] In the manufacturing process of the cover layer of Example 1, except that the first release film was replaced with one having the surface roughness and the thickness shown in Table 1, respectively.
In the same manner as in Example 1, optical information recording media of Comparative Examples 1 to 4 were produced. The manufactured optical information recording medium was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0065]

[Table 1]

From the results shown in Table 1, the optical information recording media of Examples 1 to 5 produced by the production method of the present invention have good C / N of recording characteristics and thickness unevenness, and further, It was found that there was little mixing. In particular, it was revealed that in the optical information recording medium of Example 1, since the first release film used had a small surface roughness (SRa) on both the surface A and the surface B, the thickness unevenness was very small. . On the other hand, in the optical information recording medium of Example 5, the first release film used was the surface A and the surface B.
Since both of the surface roughnesses (SRa) are relatively large, there is no problem in practical use, but the thickness unevenness is large with respect to the optical information recording media of the other examples, and the inclusion of bubbles is large. On the other hand, it is clear that the optical information recording media of Comparative Examples 1 to 4 have lower C / N of recording characteristics, larger thickness unevenness, and more air bubbles mixed in, as compared with Examples 1 to 5. became.
In particular, the first used in the optical information recording medium of Comparative Example 4
Even if the surface-roughness (SRa) of both the surface A and the surface B of the release film is small, if the thickness is small, the second release is performed by the step of winding the laminate into a roll. It was found that the surface shape of the film was transferred to the adhesive layer, and no favorable result was obtained in any evaluation.

[0067]

According to the present invention, in a method of manufacturing an optical information recording medium using a method of manufacturing a cover layer having a step of winding in a roll, an optical information recording having excellent recording characteristics and durability. A method for manufacturing a medium and an optical information recording medium manufactured by the method can be provided.
It is also possible to provide a method for manufacturing an optical information recording medium having excellent productivity, and an optical information recording medium manufactured by the manufacturing method.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view for explaining the structure of a laminated body.

FIG. 2 is a schematic cross-sectional view of an adhesive layer installation device used in an exemplary embodiment of a method for continuously providing an adhesive layer on the surface of a cover film.

[Explanation of symbols]

1, 4, 5 rolls 2 coating means 3 drying means 10 cover film 20 adhesive layer 30 first release film 40 second release film A surface B of the first release film that contacts the adhesive layer B first The other surface C of the surface A of the release film C The surface D of the second release film that contacts the cover film D The other surface of the surface C of the second release film f ₁ Release film f ₂ Cover film f ₃ Disc Film provided with a sticky adhesive layer

Claims (2)

[Claims] 1. A recording layer side surface provided on a substrate,
A method of manufacturing an optical information recording medium, comprising a cover layer comprising a cover film provided with an adhesive layer, the adhesive layer being attached to the surface so that the adhesive layer contacts the surface. Film, adhesive layer, cover film,
The second release film is produced through a step of forming a laminate formed by sequentially laminating the second release film, and a step of winding the laminate in a roll shape, wherein the first release film is the adhesive. The optical information recording is characterized in that the center surface average roughness (SRa) of the surface in contact with the surface of the layer is 50 nm or less, the center surface average roughness (SRa) of the other surface is 100 nm or less, and the thickness is 20 μm or more. Medium manufacturing method. 2. An optical information recording medium manufactured by the method for manufacturing an optical information recording medium according to claim 1.