JPS63153745A - Production of information recording medium - Google Patents

Abstract

PURPOSE:To produce an information recording medium at a low cost by forming a pregroove layer and a recording layer which permits recording/erasing of information onto a base film by a web method, then die-blanking the film to the shape of a disk. CONSTITUTION:A UV curing resin soln. is coated on the base film 5 by a coating means 6 in a coating part 1 and a coated film is formed thereon when the rolled base film 5 is let off. A stamper 7 provided with projecting parts to a spiral or concentrical circular shape is then pressed onto the coated film in tight contact therewith and UV rays from a lamp 8 are projected to the coated film from the base film side to cure the film in a stamper pressing and UV projecting part 2. The stamper 7 is removed and the pregroove layers having guide grooves is provided on the film 5. The coating liquid is coated on the groove layer by a coating means 9 in a recording layer forming part 3 and is dried 10, by which the recording layer 23 is provided. The base film 5 is finally blanked to the disk shape by a die-blanking means 11 in a die- blanking part 4. The information recording medium is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a method for manufacturing an information recording medium on which information can be written and erased using a high energy density laser beam. More specifically, the present invention relates to a method for manufacturing a flexible information recording medium.

[Technical Background of the Invention] In recent years, information recording media that use high energy density beams such as laser light have been developed and put into practical use. This information storage medium, also commonly referred to as an optical disk, is used in a wide range of applications such as video disks, audio disks, and even large-capacity still image files and large-capacity computer disk memories.

An optical disc basically consists of a disc-shaped transparent substrate made of plastic, glass, etc., and a recording layer provided thereon. Materials for the recording layer include Bi, Sn, and I.
Metals or metalloids such as n, Te, etc.; and cyanine-based, metal complex-based, quinone-based dyes, and the like are known.

Information is written on an optical disk by irradiating the optical disk with a laser beam, for example.
The irradiated portion of the recording layer absorbs the light and locally increases in temperature, resulting in a physical or chemical change that changes its optical properties, thereby recording information. Information is also read from an optical disc by irradiating the optical disc with a laser beam, and the information is reproduced by detecting reflected or transmitted light in response to changes in the optical characteristics of the recording layer.

Note that there are two types of optical disks: one that allows recording (writing) only - times (non-rewritable type) and the other that allows repeated recording and erasing (rewritable type). Furthermore, as a non-rewritable type, there is also known a read-only optical disk in which information is recorded by providing unevenness on the recording layer during the manufacturing process.

The recording layer is usually formed by depositing, sputtering, or ion plating an inorganic material such as a metal or semimetal as described above on a substrate. Therefore,
In general, U.S. disks are manufactured by providing a recording layer and the like on each substrate that has been previously formed into a disk shape. However, for the above-mentioned playback-only optical discs, after coating the base film with an ultraviolet curable resin to form a coating film, the coating film is pressed and adhered to the signal forming surface of the stamper, and then UV light is applied from the base film side. A manufacturing method (web method) is known in which a resin layer with uneven signals is formed by curing the coating film by irradiation with irradiation, and then die-cutting into a disk shape (Japanese Patent Application Laid-Open No. No. 56-87203, Special Publication No. 57-35
No. 095, No. 57-35096).

On the other hand, very recently, a polymer blend consisting of vinylidene fluoride polymer and polymethyl methacrylate has been used as the recording layer material, and information can be recorded by utilizing the state change between the compatibility state and the phase separation state of the substance. A method of
．． 1986). However, since this polymer blend itself has low absorption of light such as a laser beam, the polymer blend alone cannot actually record sufficient information, and it is difficult to put it into practical use as it is.

Therefore, the applicant placed a light-absorbing substance in contact with a polymer blend that can change state between a compatible state and a phase-separated state due to temperature changes as described above, and applied laser light to this light-absorbing substance. The light-absorbing material generates heat by irradiating and absorbing it, and the heat generation raises the temperature of the polymer blend above the cloud point between its compatible state and phase-separated state, and absorbs the light irradiated with laser light. We have already filed a patent application for an information recording method that involves changing the state of a polymer blend that is in contact with a sexual substance part and then fixing the state change of the polymer blend by rapidly cooling it, and for an information recording medium used in this method. (Tokugan Sho 6)
No. 1-181442, No. 61-181443, No. 61
-181444, 61-184539, 61-
No. 184540 and No. 61-184541).

[Summary of the Invention] An object of the present invention is to provide a method for manufacturing an information recording medium that can be mass-produced and is inexpensive.

Another object of the present invention is to provide a method for manufacturing a novel information recording medium that allows information to be recorded and erased.

The above object is to provide a method for manufacturing an information recording medium in which a pregroove layer and a recording layer on which information can be written and erased by a laser are provided on a substrate. After applying a resin to form a coating film, a step of tightly pressing a stamper provided with a convex portion in a spiral shape or a concave shape onto the coating film: or 1b) Protruding in a spiral shape or a convex shape. After applying an ultraviolet curable resin to a stamper provided with a part to form a coating film, the stamper with the coating film formed thereon is superimposed on an ultraviolet-transparent base film; 2) Applying ultraviolet rays from the base film side. Step of forming a pre-groove layer on the base film by curing the coating film made of ultraviolet curable resin by irradiation: 3) The surface of the pre-groove layer changes between a compatible state and a phase-separated state due to temperature changes. 4) forming a recording layer on the pre-groove layer by applying and drying a coating solution containing a polymer blend capable of causing change and a light-absorbing substance; and 4) providing a pre-groove layer and a recording layer. This can be achieved by the method for manufacturing an information recording medium of the present invention, which is characterized in that it includes the following steps: punching out a base film into a disk shape according to the shape of the groove.

That is, the present invention enables mass production and cost reduction of information recording media by forming a pregroove layer and a layer that can record and erase information on a base film by a web method, and then cutting it into a disk shape. This is to realize the following.

Traditionally, the web manufacturing method was applied when an ultraviolet curable resin layer (recording layer in which information is recorded) with signals formed in a concavo-convex shape is provided on a base film, that is, when manufacturing information recording media for reproduction only. It had been. According to the present invention, the pregroove layer and the recording layer can be provided by a web method. Moreover, the pre-groove layer made of ultraviolet curable resin can be provided by tightly pressing a stamper provided with guide grooves onto the coating film made of the resin formed on the base film and then curing it, or It can also be provided by forming a coating film made of the resin on a stamper in advance, and then superposing the stamper together with this coating film on a base film and curing it.

Until now, the formation of pregrooves using ultraviolet curable resin (the so-called r2P method) was thought to be suitable for manufacturing optical discs one by one using a disc-shaped substrate, that is, for small-scale production. According to the present invention, since it can be applied to a web method that allows continuous production, there is no need to apply the resin to each substrate, and a large number of substrates can be coated with one continuous coating. Similarly, a large number of recording layers can be formed by one continuous application and drying. Therefore, information recording media having a pregroove layer and a recording layer can be mass-produced and manufactured at low cost.

In addition, the recording layer formed by coating in the present invention is made of a new material that is a combination of a specific polymer blend and a light-absorbing substance, and it is possible to not only write information but also erase information by changing the state of the polymer blend. It is something.

This polymer blend has a lower critical cosolution temperature (LCS).
There are two types: T) type and upper critical cosolution temperature (UCST) type. The lower critical cosolute temperature type exhibits a phase separation state at temperatures above the cloud point, while the upper critical cosolute temperature type exhibits a miscible state at temperatures above the cloud point. is the temperature at which a polymer blend changes its composition between a compatible state and a phase-separated state. Any polymer blend changes state between a compatible state and a phase-separated state depending on temperature. In a dissolved state, the blended polymers are uniformly mixed and transparent, but in a phase-separated state, each component polymer has a different refractive index and becomes cloudy. Polymer blends also have the property of once becoming cloudy or transparent at temperatures above the cloud point and then returning to their original state when slowly cooled, but on the other hand, when rapidly cooled, they retain their same white turbidity (transparency) even at room temperature.

By irradiating the recording layer made of the above polymer blend and a light-absorbing substance with a laser beam, the light-absorbing substance absorbs the beam energy and generates heat, which causes the polymer blend to reach a temperature above its cloud point. It changes and becomes cloudy or transparent. Thereafter, by rapidly cooling the polymer blend, the area irradiated with the laser beam is fixed in this cloudy or transparent state, thereby recording information. Note that the information can be reproduced by irradiation with a relatively weak laser beam as in the conventional method. That is, information can be read based on differences in reflectance or transmittance due to differences in transparency.

Further, by raising the temperature of the polymer blend that has partially undergone a state change to above the cloud point again and then slowly cooling it, the light irradiated area (recording area) can be returned to its original state.

This operation restores the entire polymer blend to its original transparent or cloudy state and erases the recorded information.

Therefore, the information recording medium manufactured by the method of the present invention is an E-DRAW medium capable of recording and erasing information at any time.
(Erasable-Direct Read Af
It is useful as a terWrite type recording medium.

[Structure of the Invention] A method for manufacturing an information recording medium of the present invention will be outlined with reference to the accompanying drawings.

FIG. 1 is a diagram schematically showing an example of an apparatus used in the manufacturing method of the present invention.

In FIG. 1, the manufacturing apparatus includes an ultraviolet curable resin coating section 1, a stamper pressing and ultraviolet irradiation section 2. It is composed of a recording layer forming section 3 and a die cutting section 4.

When the base film 5 wound into a roll is unwound, an ultraviolet curable resin solution is first applied onto the base film S by the application means 6 in the application section 1 to form a coating film. Next, the stamper pressing and ultraviolet irradiation section 2 applies a stamp on the coating film made of ultraviolet curable resin.
A stamper 7 provided with a convex portion in a spiral or circular shape (guide groove shape) is tightly pressed, and in this state ultraviolet light is irradiated from the base film side by an ultraviolet lamp 8. As a result, the coating film made of the ultraviolet curable resin is cured.Next, the stamper 7 is removed and a pregroove layer having guide grooves is provided on the base film.

Further, in the recording layer forming section 3, a coating liquid for forming a recording layer is applied onto the pregroove layer by the coating means 9 to form a coating film, and then the coating film is dried in a drying zone IO to form a recording layer. provided. Finally, in the die-cutting section 4, the base film provided with the pre-groove layer and the recording layer is punched out into a disk shape by the die-cutting means 11 to obtain an information recording medium. Note that the base film after being punched out is wound up again.

However, the above manufacturing apparatus is an example of the apparatus used in the manufacturing method of the present invention, and the method of the present invention is not limited to the above embodiment. For example, instead of providing the application part l of the ultraviolet curable resin, the stamper 7 can be used in advance.
A coating film is formed by applying an ultraviolet curable resin solution to the uneven surface of the stamper, and in the stamper suppression and ultraviolet irradiation section 2, this coating film is superimposed on the stamper or base film on which it has been formed, and then irradiated with ultraviolet rays. A pre-groove layer may also be formed.

FIG. 2 is a sectional view showing an example of the structure of an information recording medium according to the present invention manufactured by the above method.

In FIG. 2, the information recording medium is composed of a substrate 21, a pregroove layer 22, and a recording layer 23 in this order. The recording layer 23 consists essentially of a polymer blend and a light-absorbing material.

However, the information recording medium manufactured by the manufacturing method of the present invention is not limited to the above embodiment, and for example, a reflective layer may be provided on the side of the recording layer opposite to the side in contact with the pregroove layer. good.

Below, the method for manufacturing the information recording medium of the present invention will be explained in detail.

In the present invention, the elongated base film that can serve as the substrate of the information recording medium is transparent to ultraviolet rays, has a uniform thickness, and has low elasticity. Materials for such base films include, for example, polyethylene terephthalate, polycarbonate, polyimide, triacetyl cellulose, polyvinyl chloride, and polypropylene. The thickness of the base film is generally lO
-11000p, preferably 50-300p
It is in the μm range.

An undercoat layer may be provided on the surface of the base film for the purpose of improving flatness, improving adhesive strength, and preventing deterioration of the recording layer. Examples of materials for the undercoat layer include polymethyl methacrylate, acrylic acid/methacrylic acid copolymer, styrene/maleic anhydride copolymer, polyvinyl alcohol, N-methylolacrylamide, styrene/sulfonic acid copolymer, styrene/maleic anhydride copolymer, Vinyl toluene copolymer, chlorosulfonated polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, vinyl acetate/vinyl chloride copolymer, ethylene/vinyl acetate copolymer, polyethylene, polypropylene, polycarbonate, etc. Organic substances such as polymeric substances and nitrogen coupling agents; and inorganic oxides (Si02, A
120, etc.) and inorganic substances such as inorganic fluorides (MgF2).

The undercoat layer is formed by, for example, dissolving or dispersing the above-mentioned substance in a suitable solvent, applying this coating solution to the base film surface by a coating method such as a roll coating method, a gravure offset coating method, or a dip coating method, and then drying it. It can be formed by The layer thickness of the undercoat layer is generally 0.0
0.05 to 20 Bm, preferably 0.05 to 20 Bm. O1~1
It is in the range of 0 lm.

On this base film, tracking grooves and/or
Alternatively, a pregroove layer having irregularities representing information such as an address signal is provided.

As the material for the pregroove layer made of an ultraviolet curable resin, a mixture of at least one monomer or oligomer of acrylic acid monoesters, diesters, triesters, and tetraesters and a photopolymerization initiator can be used.

The oligomers constituting the ultraviolet curable resin used in the present invention include mono-, di-, and tri-(
I can mention meth)acrylates.

(a) Poly(meth)acrylates of aliphatic, alicyclic, araliphatic di- to hexavalent polyhydric alcohols and polyalkylene gelicols: For example, ethylene glycol, propylene glycol,
1.3- or 1.4-butanediol, hexanediol, neopentyl glycol, cyclohexanediol, trimethylolethane, trimethylolpropane,
Poly(meth)acrylates of polyhydric alcohols such as glycerin, sorbitol, pentaerythritol, dipentaerythritol, hydrogenated bisphenol A; and poly(meth)acrylates such as diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol Examples include poly(meth)acrylates of alkylene gelylcols.

Incidentally, these specific examples are described in Japanese Patent Application Laid-open No. 12098/1983.

(b) Poly(meth)acrylate of polyhydric alcohol in the form of aliphatic, alicyclic, araliphatic, aromatic di- to hexavalent polyhydric alcohol with alkylene oxide added: For example, bisphenol A dioxyethyl Examples include poly(meth)acrylates of polyhydric alcohols such as ethers, which are obtained by adding ethylene oxide or propylene oxide to polyhydric alcohols such as trimethylolpropane, pentaerythritol, glycerin, and bisphenol A.

(C) Poly(meth)acryloyloxyalkyl phosphate ester: Obtained by reaction of hydroxyl group-containing (meth)acrylate with phosphorus pentoxide, for example, poly(meth)acryloyloxyethyl phosphate, poly(meth)acryloyl Oxypropyl phosphate is mentioned.

(d) Polyester poly(meth)acrylate: Usually synthesized by esterifying (meth)acrylic acid, polyhydric alcohol, and polyhydric carboxylic acid. It is estimated that poly(meth)acrylate, a polyester-type polyhydric alcohol, is the main component, and synthesis examples and specific examples thereof can be found in JP-A-49-128944 and other published patent publications (49-128088, 49-120981). ，
49-93473, 49-28692, 48-9651
5, 48-66679, 48-25790, etc.).

For example, di(meth)acrylate of polyester diol of cohelic acid and ethylene glycol, di(meth)acrylate of polyester diol of maleic acid and ethylene glycol, di(meth)acrylate of polyester diol of phthalic acid and diethylene glycol, Di(meth)acrylate of polyester diol with tetrahydrophthalic acid and diethylene glycol, poly(meth)acrylate of polyester diol with adipic acid and triethylene glycol, poly(meth)acrylate of polyester polyol with tetrahydrophthalic acid and trimethylolpropane , poly(meth)acrylate of polyester polyol of tetrahydrophthalic acid and pentaerythritol.

Among these polyester poly(meth)acrylates, when using aliphatic or alicyclic polycarboxylic acid-based polyester poly(meth)acrylates rather than aromatic polycarboxylic acid-based ones such as phthalic acid, The resulting crosslinked cured product has better properties such as weather resistance and toughness.

(e) 2 molecules of epoxy poly(meth)acrylate
(meth)acrylic acid, carboxyl group-containing (meth)acrylate, or (meth)acrylic acid or carboxyl group-containing (meth)acrylate and polybasic acid in an epoxy resin having at least 3 epoxy groups, approximately equivalent to the epoxy group. It is synthesized by a method such as reacting a mixture of

Alternatively, it can be synthesized by a method such as reacting an epoxy group-containing (meth)acrylate with a polyhydric carboxylic acid.

Synthesis examples and specific examples of epoxy poly(meth)acrylate are disclosed in JP-A-49-28692 and other published patent publications (4B-66182, 48-60787, 49-12).
090, etc.), Japanese Patent Publication No. 12091/1987 and 4
It is described in Publication No. 9-12090 and the like.

For example, addition reaction between various epoxy resins such as bisphenol A diglycidyl ether type, glycerin diglycidyl ether type, polyalkylene gellicol diglycidyl ether type, polybasic acid diglycidyl ester type, and cyclohexene oxide type, and (meth)acrylic acid. products.

<f) Polyurethane poly(meth)acrylate: It has the structure of a polyhydric alcohol (meth)acrylate having a polyurethane bonding unit in the main chain, and usually contains a hydroxyl group-containing (meth)acrylate, a polyisocyanate, and if necessary a polyhydric alcohol. It is synthesized by a method such as reacting with Synthesis examples and specific examples are given in JP-A-48-60787.
It is stated in the publication number etc.

For example, addition reaction products of 2-hydroxyethyl (meth)acrylate or 2-hydroxypropyl (meth)acrylate and diisocyanate, addition reaction products of 2-hydroxyethyl (meth)acrylate, diisocyanate, and dihydric alcohol, etc. corresponds to this example.

(g) Polyamide poly(meth)acrylate: It has the structure of a polyhydric alcohol (meth)acrylate with a polyamide bonding unit in the main chain, and is usually a (meth)acrylate containing a hydroxy group in a boria-mido type polycarboxylic acid. Or react with epoxy group-containing (meth)acrylate,
Alternatively, it can be synthesized by reacting (meth)acrylic acid with a polyamide-type polyhydric alcohol. Synthesis examples and specific examples can be found in JP-A No. 48-60787 and JP-A No. 48-6078.
It is described in JP-A-37246 and the like.

For example, a reaction product of a polyamide-type polycarboxylic acid obtained by the reaction of ethylenediamine and phthalic acid with 2-hydroxyethyl (meth)acrylate or glycidyl (meth)acrylate corresponds to this example.

(h) Polysiloxane poly(meth)acrylate: It has a (meth)acrylate structure of a polyhydric alcohol having a polysiloxane bonding unit in the main chain, and is usually a (meth)acrylate of a polyhydric alcohol having a polysiloxane bonding unit. Synthesis examples and specific examples of 0 synthesized by methods such as reacting acids or hydroxyl group-containing (meth)acrylates are described in Japanese Patent Publication No. 49-4296 and the like.

(i) Vinyl-based or diene-based low polymer having (meth)acryloyloxy groups in the side chain and/or terminal: Ester bond, urethane bond, amide bond in the side chain or terminal of the vinyl-based or diene-based low polymer , has a structure in which a (meth)acryloyloxy group is bonded via an ether bond, etc. Low polymerization usually has a hydroxyl group, carboxyl group, epoxy group, etc. in the side chain or terminal
In the body, (meth)acrylic acid, carboxyl group-containing (meth)acrylate, hydroxyl group-containing (meth)acrylate, epoxy group-containing (meth)acrylate, isocyanate group-containing (meth)acrylate, amino group It is synthesized by a method such as reacting containing (meth)acrylates. Synthesis examples and specific examples are described in JP-A-50-9687, JP-B No. 45-15629, JP-A-45-15630, and the like.

For example, there may be mentioned a reaction product obtained by reacting a copolymer of (meth)acrylic acid and another vinyl monomer with glycidyl (meth)acrylate.

Note that crosslinkable monomers belonging to this system generally tend to become highly viscous or solid as their molecular weight increases, so they should be used after being dissolved in a liquid low viscosity crosslinking monomer as described below, or Low molecular weight (usually number average molecular weight 3,000
It is preferable to use the following liquid ones.

(j) Modified products of the crosslinkable monomers described in (a) to (i) above: At least a part of the hydroxyl group or carboxyl group remaining in each of the above crosslinkable monomers is reacted with these groups. It is a modified product obtained by reacting with an acid chloride, acid anhydride, isocyanate or epoxy compound, and the modification method and specific examples are described in JP-A-49-1289.
It is described in Japanese Patent Application Laid-Open No. 49-128088, etc.

Among the oligomers mentioned above, those particularly suitable for the present invention are (b), (d), (e) and (f).
Further, as the monomers constituting the ultraviolet curable resin used in the present invention, the following (meth)acrylates (i) to (x) can be mentioned.

(t) CH*=Cl-C0O-CaH2n+, (where n is an integer from 1 to 12) (ii) C) It
-CH-COO-(CHtCHtO)-R, n is 1 to
(1ii) CHt”Cl-C0O-(CHzCH*0
) t-RO,l, 4.8 or 9) (iv) (it) and (iit) -(CHtC
H2G)- chain changed to CH3 -CH, -CH-0- chain (V) CH, -CH-tl: 0O-X-OH dicyclopentadienyloxyethyl acrylate hydrogenated dicyclopentadienyloxy Ethyl acrylate (vii) CHx CH, proverbially C-C0OR” OH (where R1 is -CH, CH20H1-CI2C) lcHi or -CI (3) (viii) N-vinylpyrrolidone (ix) isobornyl acrylate, di Cyclopentadienyl acrylate, hydrogenated dicyclopentadienyl acrylate (x) styrene These oligomers and monomers may be used alone, or in blends of oligomers, blends of oligomers, or oligomers and monomers. However, it is desirable that the adhesion to the base film is good.

Examples of photopolymerization initiators include benzoin alkyl ethers, benzyl ketals, acetals, acetophenone derivatives, benzophenone derivatives, xanthone derivatives,
Examples include thioxanthone derivatives, anthraquinone derivatives, and benzaldehyde derivatives. In addition, specific examples of compounds that can be used as sensitizers include:
Benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzophenone, benzyl, 2.2-dimethoxy-2-phenylacetophenone, 2.2-dimethoxy-2-hydroxyacetophenone, diphenyl disulfide, 2-hydroxy-2- Propiophenone, 4,4'-bisdiethylaminobenzophenone, dimethylaminobenzaldehyde,
Mention may be made of ethyl-4,4'-bisdimethylaminobenzophenone, ethyl anthraquinone, and 2-chlorothioxanthone. These sensitizers can be used alone or in appropriate combinations.

Furthermore, the ultraviolet curable resin may contain a silane coupling agent, and examples of the silane coupling agent include γ-glycidoxyprobyltrimethoxysilane, β-(3,4-epoxycyclohexyl) Epoxysilane-based silane coupling agents such as ethyltrimethoxylane; aminosilane-based silane coupling agents such as N-β-aminoethyl-γ-aminopropyltrimethoxysilane and N-β-aminoethyl-γ-aminopropylmethyldimethoxysilane Ring agent: A vinyl silane-based silane coupling agent such as γ-methacryloxypropyltrimethoxysilane is preferred.

The pregroove layer can be formed on the base film, for example, by the following method.

First, a coating solution is prepared by mixing the above acrylic ester, a photopolymerization initiator, and, if necessary, a silane coupling agent. This coating liquid is applied uniformly to the base film surface by a coating method such as a roll coating method, a gravure offset coating method, or a dip coating method to form a coating film. A stamper with precisely formed protrusions is pressed tightly against the coating film with the protrusions facing the coating film. In this state, the coating film made of the ultraviolet curable resin is irradiated with ultraviolet light through the base film to cure the coating film. By peeling off the stamper from the base film, a pregroove layer having a spiral or concentric guide groove is formed on the base film. As the ultraviolet lamp, a high pressure mercury lamp, a metal halide lamp, etc. are used.

Alternatively, instead of applying the coating liquid onto the base film, you can apply it to the surface of the convex side of the stamper to form a coating film, and then overlap the stamper on the base film so that the coating film is on the base film side. In this state, UV rays are irradiated from the base film side to harden the coating film and fix the base film and coating film, and then the pre-groove layer is formed in the same way by peeling off the stamper from the base film. A base film is obtained.

The thickness of the pre-groove layer is generally 0.05 to 1100p.
, preferably in the range of 0.1 to 501 Lm. Further, the guide groove formed on the surface of the pregroove layer generally has a depth in the range of 300 to 1300 mm,
The distance (pitch) between the grooves is in the range of 0.5 to 2 m.

Next, a recording layer is formed on the pregroove layer. The recording layer is a layer consisting essentially of a polymer blend containing and supporting a light-absorbing substance in a dispersed state.

The polymer blend used as a material for the recording layer in the present invention is a mixture of two or more types of polymers, and can undergo a state change between a compatible state and a phase-separated state. However, a combination of a polymer and a monomer may exhibit similar behavior, and such compositions are also included in the polymer blend of the present invention.

Polymer blends can be roughly divided into lower critical cosolute temperature (LCST) types, which are transparent and compatible at room temperature, but phase separate and become cloudy at temperatures above the clouding point, and conversely, those with a cloudy phase at room temperature. There is an upper critical solution temperature (UCST) type that is in a separated state and becomes compatible and transparent at a high temperature above the cloud point.

FIG. 3 shows an example of a phase diagram for a LCST type polymer blend. The horizontal axis shows the volume fraction of one polymer when two types of polymers are blended, and the vertical axis shows the temperature.

In FIG. 3, each point on the curve is a cloud point for that composition. Region below this cloud point (lower side of the curve in Figure 3)
shows a compatible state (transparent), and a high temperature region above the cloud point (third
The upper part of the curve in the figure) is a phase-separated state! s (cloudy). Further, since the polymer blend is uniformly mixed regardless of the composition at a temperature lower than the temperature Tc (lowest cloud point temperature), this temperature Tc is called the lower critical cosolution temperature.

In the case of a UCST type polymer blend, on the contrary, the phase diagram becomes an upwardly convex curve, and the upper critical cosolution temperature is similarly determined.

The cloud point of the polymer blend varies depending on the type of polymer, its composition, and in the case of amorphous polymers, its molecular weight distribution and molecular weight, but it is preferably in the range of 60 to 400°C, particularly preferably 80 to 300°C. in the range of ℃.

Examples of LCST type polymer blends include: l) Combinations of amorphous polymers: polystyrene and polyvinyl methyl ether, styrene.
Acrylonide-lyl copolymer and poly-6-caprolactone, styrene-acrylonitrile copolymer and polymethyl methacrylate, polyvinyl nitrate and polymethyl acrylate, ethylene-vinyl acetate copolymer and chlorinated rubber, poly(-caprolactone and Polycarbonate (bisphenol Affi), p-chlorostyrene/0-chlorostyrene copolymer and poly(2,6-dimethyl-1,4-phenylene oxide), polycarbonate (bisphenol A type) and ethylene oxide block copolymer, butylene terephthalate・Tetrahydrofuran block copolymer and polyvinyl chloride, thermoplastic polyurethane [poly-ε-caprolactone soft block] and polyvinyl chloride; 2) Combination of crystalline polymer and amorphous polymer: ゛Polyvinylidene fluoride and polymethyl acrylate; polyvinylidene fluoride and polyethyl acrylate, polyvinylidene fluoride and polymethyl methacrylate, polyvinylidene fluoride and polyethyl methacrylate, polyvinylidene fluoride and polyvinyl methyl ketone; and 3) a combination of a crystalline polymer and a crystalline upper layer. : Polyethylene oxide and trioxane, poly-ε-caprolactone and trioxane;

Examples of UCST type polymer blends include combinations of amorphous polymers such as polystyrene and polyisoprene, polystyrene and polyisobutyne, polypropylene oxide and polybutadiene, polyisobutyne and polydimethylsiloxane, and the like.

In addition, these polymers can be made into a copolymer with an appropriate amount of heptamer within the range showing LC3T and UCST.

The light-absorbing material used in the present invention has a high absorption rate for laser light and exhibits a heat-generating effect by absorbing light.

Since the use of semiconductor lasers that emit near-infrared light as recording and reproducing lasers has been put into practical use, the light-absorbing substance is preferably a dye that has a high absorption rate for light in the near-infrared region of 700 to 900 nm. Examples include: i) Cyanine dye: [11(CH+)J-(CH-(:H)s-CH-"N
(CHz)t C04- (however, n is 2 or 3
) Margin below N(cL)2' ”N(CH3)2
RR (However, R is a hydrogen atom or N(CHs)2) (R is an alkyl group, and an alkyl group, an alkoxy group, an aralkyl group, an alkenyl group; benzene carboxylate, methyl carboxylate or trifluoromethyl carboxylate, n is an integer from O to 3) [6] Φ-
L='l' (X-).

(However, Φ and ! are each an indole ring residue or a benzindole ring residue, L is a linking group for forming monocarbocyanine, dicarbocyanine, tricarbocyanine or tetracarbocyanine, and
- is an anion and 1m is O or 1) it) squarylium dye: C(CH3)5 O-C(CHs): +1ii) Thiol nickel complex dye: (However, X is a hydrogen atom,
A chlorine atom, a bromine atom or a methyl group, and n is 1 to 4
and A is a quaternary ammonium group)iV
) Naphthoquinone-based, anthraquinone-based pigments: (Tatashi,
R is a hydrogen atom or OC, H,) R'
0 (wherein R is OH, NH2, NHX or NX*tea, where X is an alkyl group and X' is a hydrogen atom, an alkyl group, an allyl group, an amino group or a substituted amino group) ON ) It 0 0 NH,S and the like. In addition to these dyes, triallylmethane dyes, phthalocyanine dyes, immonium dyes, nitroso compounds, and the like can also be used.

To form the margin recording layer, first prepare a coating solution by dissolving the above polymer blend and light-absorbing substance in a suitable solvent, and then apply this coating solution to the surface of the pregroove layer to form a coating film. This can be done by drying.

Solvents for preparing the coating solution include toluene, xylene, ethyl acetate, butyl acetate, cellosolve acetate, methyl ethyl ketone, dichloromethane, 1,2-dichloroethane, dimethylformamide, methyl isobutyl ketone,
Examples include solvents for dissolving or dispersing polymer blends and light-absorbing substances, such as cyclohexanone, cyclohexane, tetrahydrofuran, ethyl ether, dioxane, ethanol, n-propanol, isopropanol, n-butanol, and mixed solvents thereof. . Depending on the purpose, various additives such as antioxidants, UV absorbers, plasticizers, and lubricants may be added to the coating liquid.

Examples of the coating method include a roll coating method and a gravure offset coating method.

The mixing ratio of the polymer blend and the light-absorbing substance in the coating solution varies depending on the type of these substances, or is generally 1.
It is in the range of 00:0.1 to 100:100 (weight ratio), preferably in the range of Zoo:1 to 100:50.

Further, the recording layer may be a single layer or a multilayer, but the layer thickness is generally 0.01 mm from the viewpoint of optical density required for optical information recording.
~104m, preferably 0.02~IJL
It is in the range of m.

The base film provided with the pregroove layer and the recording layer is then die-cut into a disk shape. A disk-shaped die cutter is used to punch out the base film together with the pregroove layer and the recording layer into a disk shape.

In this way, an information recording medium consisting of a substrate, a pregroove layer and a recording layer in this order is obtained (see FIG. 2).

After punching out the disc shape, a reflective layer may be provided on the recording layer for the purpose of improving the S/N ratio during information reproduction and improving sensitivity during recording. Recording and reproduction are performed by irradiating the recording layer with a laser beam from the substrate side.

The reflective layer is a layer consisting essentially of a light reflective material.

A light-reflective substance is a substance that has a high reflectance to laser light, and examples thereof include Mg and Se.

Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo,
W, Mn, Re, Fe, Co, Ni.

Ru, Rh, P, I r, Pt, Cu, Ag, Au,
Zn, C, An, Ga, In, Si.

Mention may be made of metals and metalloids such as Ge, Te, Pb, Po, Sn, and Bi. Among these, A9 is preferable. , Cr and Ni.

These substances may be used alone, or in combination of two or more, or as an alloy.

The reflective layer can be formed on the recording layer by, for example, vapor deposition, sputtering, ion plating, or the like using the above-described light-reflecting material.The thickness of the reflective layer is generally in the range of 100 to 3000 mm.

In addition, on the surface (exposed surface side) of the recording layer or reflective layer,
A protective layer may be provided for the purpose of physically and chemically protecting the recording layer. Further, the protective layer may be provided on the side of the substrate where the pregroove layer is not provided for the purpose of increasing scratch resistance and moisture resistance.

Examples of materials used for the protective layer include 5iO1Si0
Non-f & substances such as 2, MgF, 5n02; and 4:1 substances such as thermoplastic resins, thermosetting resins, and UV curable resins can be mentioned.

The protective layer can be formed, for example, by laminating a film obtained by plastic extrusion onto the recording layer (or reflective layer) and/or the substrate via an adhesive layer. Or vacuum evaporation, sputtering,
It may be provided by a method such as coating. In the case of thermoplastic resins and thermosetting resins, after preparing a coating liquid by dissolving them in an appropriate solvent, apply this coating liquid to the recording layer 3.
It can also be formed by coating and/or drying on a substrate. In the case of LTV curable resin, it can be cured by applying it as it is or by dissolving it in an appropriate solvent to prepare a coating solution, then applying this coating solution onto the recording layer and/or substrate, and curing it by irradiating it with UV light. can also be formed. Various additives such as antistatic agents, antioxidants, and UV absorbers may be added to these coating solutions depending on the purpose. may be performed before punching out the base film into a disc shape.

The thickness of the protective layer is generally in the range of 0.1 to 1100 p.

The information recording medium may be a single board having the above structure, or alternatively, by facing two substrates having the above structure so that the recording layer is on the inside and bonding them together using an adhesive or the like, A laminated type information recording medium can also be manufactured. Alternatively, an air sandwich type information recording medium is manufactured by using a substrate having the above configuration as at least one of two disk-shaped substrates and joining them via a ring-shaped outer spacer and a ring-shaped inner spacer. You can also.

Examples of the present invention are described below. However, each example does not limit the present invention.

[Example 1] On a two-wheel stretched polyethylene terephthalate film (base film, thickness: 10,100 u), an ultraviolet curable resin solution having the following composition was applied by roll coating to form a coating film with a film thickness of 201 Lm.

, fibrinolytic group Pentaerythritol propyl ether triacrylate 64% by weight N-vinylpyrrolidone 16% by weight Hexanediol diacrylate 16% by weight Benzyl dimethyl ketal
4% by weight Next, a stamper having convex portions in a spiral shape (height of convex portions = 800, pitch = 1.6 p.
, m) was tightly pressed onto the base film with the convex side facing down to prevent bubbles from entering, and then heated with a high pressure mercury lamp (8
0 W/cm) were lined up and irradiated with ultraviolet rays for 10 seconds through this base film to cure the coating film made of the ultraviolet curable resin. The stamper was peeled off from the base film to obtain a pregroove layer having spiral guide grooves on the base film.

Next, a toluene solution of an LCST type polymer blend of polystyrene and polyvinyl methyl ether and a dichloroethane solution of a cyanine dye (the above structural formula [5]: % formula %) are thoroughly mixed to prepare a coating solution. did. The mixing ratio of the polymer blend and cyanine dye in the coating liquid was Zoo:10 (weight ratio).

This coating solution was applied onto the pregroove layer by roll coating and then dried to provide a recording layer having a dry film thickness of 0.1 lm.

The base film provided with the pre-groove layer and the recording layer was adjusted to the perfect circle of the groove, with an inner diameter of 15 mm and an outer diameter of 1 mm.
It was punched out into a 30 mm disc shape.

In this way, an information recording medium consisting of a substrate, a pregroove layer, and a recording layer as shown in FIG. 2 was manufactured.

Semiconductor laser light (wavelength: 830n) is applied to this information recording medium.
m, irradiation power: 10mW, beam diameter: 1.6JLm)
After writing information by irradiating the
When the information was read by irradiating with a beam diameter of 1.6 pm, binary information was obtained.

[Example 2] In Example 1, LCS of a combination of polyvinylidene fluoride and polymethyl methacrylate was used as a polymer blend.
An information recording medium consisting of a substrate, a pregroove layer, and a recording layer was manufactured in this order by performing the same treatment as in Example 1 except for using a dimethylacetamide solution of the T-type polymer blend.

When the obtained information recording medium was subjected to the same operations as in Example 1 to write and read information, binary information was obtained.

[Example 3] In Example 1, LCS of a combination of polyvinylidene fluoride and polymethyl methacrylate was used as the polymer blend.
A disk-shaped substrate provided with a pregroove layer and a recording layer was obtained by carrying out the same treatment as in Example 1 except for using a dimethylacetamide solution of the T-shaped polymer blend.

Next, aluminum was vacuum-deposited on the recording layer to form a reflective layer having a thickness of 1,000 layers. moreover,
A protective layer having a layer thickness of 11001 L was formed by laminating a polyester film onto the reflective layer using an adhesive.

In this way, the substrate, pregroove layer, recording layer,
An information recording medium consisting of a reflective layer and a protective layer was manufactured.

When information was written and read on the obtained information recording medium in the same manner as in Example 1, binary information was obtained with a high S/N ratio.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of a manufacturing apparatus used in the manufacturing method of the present invention. FIG. 2 is a sectional view showing an example of an information recording medium manufactured according to the manufacturing method of the present invention. FIG. 3 shows a phase diagram of a polymer blend of the LCST type. 1: UV curable resin coating section, 2: Stamp bar pressing and UV irradiation section, 3: Recording layer forming section, 4: Die cutting section, 5: Base film, 6.9: Coating means, 7: Stamper, 8: Ultraviolet rays Lamp, lO: drying zone, 11: uncovering means. 21: Substrate, 22 nibreg group layer. 23: Recording layer, Patent applicant: Fuji Photo Film Co., Ltd. Agent: Yasushi Yanagawa, patent attorney Figure 3 Volume fraction

Claims (1)

[Claims] 1. A method for manufacturing an information recording medium in which a pre-groove layer and a recording layer on which information can be written and erased by a laser are provided on a substrate, including: 1a) applying an ultraviolet curable resin to an ultraviolet-transparent base film; After forming the coating film, a step of tightly pressing a stamper provided with a spiral or concentric circular convex portion onto this coating film; or 1b) a step in which a spiral or concentric circular convex portion is provided After applying an ultraviolet curable resin to the stamper to form a coating film, the stamper with the coating film formed thereon is superimposed on an ultraviolet-transparent base film; 2) UV curing by irradiating ultraviolet rays from the base film side 3) A step of forming a pre-groove layer on the base film by curing a coating film made of a synthetic resin. 4) forming a recording layer on the pre-groove layer by applying and drying a coating solution containing a blend and a light-absorbing substance; and 4) applying the base film provided with the pre-groove layer and the recording layer to the groove. A method for manufacturing an information recording medium, comprising: punching out a disc shape according to the shape. 2. 2. The method for manufacturing an information recording medium according to claim 1, wherein the base film has a long shape, and the first to fourth steps are performed continuously. 3. 2. The method of manufacturing an information recording medium according to claim 1, wherein after the fourth step, a reflective layer is formed by vapor deposition, sputtering, or ion plating of a reflective substance on the surface of the recording layer. 4. Claim 1, wherein the polymer blend is a lower critical cosolubilization temperature type polymer blend.
Method for manufacturing the information recording medium described in Section 1. 5. Claim 1, wherein the polymer blend is an upper critical cosolubilization temperature polymer blend.
Method for manufacturing the information recording medium described in Section 1.