EP0144705A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Optical recording medium and process for producing the same
Assignee: Sumitomo Bakelite Co Ltd
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Filing: 1984-10-29
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Granted: —
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Expires: 2004-10-29
Abstract
Abstract In an optical recording medium (optical disk recording medium) on which information can be optically written, read and erased by use of a laser light and which comprises a transparent substrate of a synthetic resin and an information-recording layer provided on the surface of the substrate, said synthetic resin consists of an epoxy resin composition comprising an alicyclic epoxy resin or a mixture of an alicyclic epoxy resin and an aromatic epoxy resin; an organic polybasic acid anhydride; a curing accelerator; and an anti-discoloring (anti-oxidizing) agent, the above substrate is a cured product of a cast article of the epoxy resin composition and has a Si0 2 or SiO layer or a hard coat layer of a synthetic resin which may have a Si0 2 or SiO layer on its surface, whereby the substrate has thermal resistance and abrasion or scratch resistance, and on said layer there is provided an information-recording layer made of a low melting point metal such as Te, Se, Bi or the like or a complex material of said metal and an organic material or a rare earth metal and transition metal series magnetic alloy such as Td-Gd-Fe or the like. Said transparent substrate can easily be obtained by forming a thin film of MgF 2 , CaF 2 or SiC on the inner surface of a casting mold by an ion-plating method, a spattering method or the like in order to facilitate the release of the molded article of the epoxy resin composition from the casting mold, and casting the epoxy resin composition into the mold. The Si 2 0 or SiO layer or the hard coat of synthetic resin is applied on the thus obtained substrate and the information-recording layer is then applied thereto in a conventional manner. The hard coat of synthetic resin can easily be formed by first applying the hard coat layer on the inner surface of the casting mold, then casting the epoxy resin composition into the casting mold and curing the same to transfer the hard coat onto the cured molded article of the epoxy resin composition.
Inventors
- 👤 Morio Tsuge
- 👤 Setsuo Suzuki
- 👤 Syoichi Nakayama
- 👤 Yushi Sakamoto
- 👤 Koji Morishita
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 12:28
CPC Classifications
C; C08; C08G; C08G59/00; C08G59/18; C08G59/20; C08G59/22; C08G59/24; C08G59/226; C09; C09D; C09D4/00; G; G11; G11B; G11B23/00; G11B23/0057; G11B23/0064; G11B23/0092; G11B7/00; G11B7/24; G11B7/241; G11B7/252; G11B7/253; G11B7/2533; G11B7/254; G11B7/2548; G11B7/242; G11B7/243; G11B2007/24302; G11B2007/24316; G11B2007/24318; G11B2007/24324; G11B2007/24328; G11B7/2534; G11B7/2542; G11B7/257; G11B7/2578
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
66 words
An optical recording medium comprising a transparent substrate of a synthetic resin and an information-recording layer provided thereon, on which medium information can be optically written, read and erased by means of a laser light, said transparent substrate consisting essentially of a cast-cured product of an epoxy resin composition comprising an alicyclic epoxy resin, an organic polybasic acid anhydride, a curing accelerator and an anti-discoloring agent.
Claim 2
Dependent Claim
66 words
An optical recording medium comprising a transparent substrate of a synthetic resin and an information-recording layer provided thereon, on which medium information can be optically written, read and erased by means of a laser light, said transparent substrate consisting essentially of a cast-cured product of an epoxy resin composition comprising an alicyclic epoxy resin, an organic polybasic acid anhydride, a curing accelerator and an anti-discoloring agent.
Claim 3
Dependent Claim
82 words
An optical recording medium comprising a transparent substrate of a synthetic resin and an information-recording layer provided thereon, on which medium information can be optically written, read and erased by means of a laser light, said transparent substrate consisting essentially of a cast-cured product of an epoxy resin composition comprising a mixture of a major amount of an alicyclic epoxy resin and a minor amount of an aromatic epoxy resin, an organic polybasic acid anhydride, a curing accelerator and an anti-discoloring agent.
Claim 4
Dependent Claim
82 words
An optical recording medium comprising a transparent substrate of a synthetic resin and an information-recording layer provided thereon, on which medium information can be optically written, read and erased by means of a laser light, said transparent substrate consisting essentially of a cast-cured product of an epoxy resin composition comprising a mixture of a major amount of an alicyclic epoxy resin and a minor amount of an aromatic epoxy resin, an organic polybasic acid anhydride, a curing accelerator and an anti-discoloring agent.
Claim 5
Dependent Claim
39 words
An optical recording medium according to Claim 1, wherein the transparent substrate has a SiO or Si0 2 film bonded to one side or both sides and the information-recording layer is bonded to the SiO or Sio 2 film.
Claim 6
Dependent Claim
39 words
An optical recording medium according to Claim 2, wherein the transparent substrate has a SiO or Si0 2 film bonded to one side or both sides and the information-recording layer is bonded to the SiO or SiO 2 film.
Claim 7
Dependent Claim
39 words
An optical recording medium according to Claim 1, wherein the transparent substrate has a coating film of a radiation-curable resin bonded to one side or both sides and the information-recording layer is bonded to the radiation-curable resin coating film.
Claim 8
Dependent Claim
39 words
An optical recording medium according to Claim 2, wherein the transparent substrate has a coating film of a radiation-curable resin bonded to one side or both sides and the information-recording layer is bonded to the radiation-curable resin coating film.
Claim 9
Dependent Claim
58 words
An optical recording medium according to Claim 1, wherein the transparent substrate has a coating film of a radiation-curable resin or a thermosetting resin bonded to one side or both sides and a SiO or Si0 2 film is further bonded to said coating film, and the information-recording layer is attached to the SiO or Si0 2 film.
Claim 10
Dependent Claim
58 words
An optical recording medium according to Claim 2, wherein the transparent substrate has a coating film of a radiation-curable resin or a thermosetting resin bonded to one side or both sides and a SiO or SiO 2 film is further bonded to said coating film, and the information-recording layer is attached to the SiO or Si0 2 film.
Claim 11
Dependent Claim
24 words
An optical recording medium according to Claim 2, 4 or 6, wherein the cast-cured product has an index of refraction of 1.50 to 1.60.
Claim 12
Dependent Claim
28 words
An optical recording medium according to Claim 5, 6, 7 or 8, wherein the coating film of a radiation-curable resin has a pencil hardness of 4H or more.
Claim 13
Dependent Claim
21 words
An optical recording medium according to Claim 5, 6, 7 or 8, wherein the radiation-curable resin is a ultraviolet ray-curable resin.
Claim 14
Dependent Claim
38 words
An optical recording medium according to Claim 5, 6, 7 or 8, wherein the transparent substrate has a coating film of a radiation-curable resin on both sides and the coating films are of the same kind of resin.
Claim 15
Dependent Claim
37 words
An optical recording medium according to Claim 5, 6, 7 or 8, wherein the transparent substrate has a coating film of a radiation-curable resin on both sides, and the coating films are of different kinds of resins.
Claim 16
Dependent Claim
43 words
An optical recording medium according to Claim 5, 6, 7 or 8, wherein the transparent substrate has a coating film of a thermosetting resin on one side or both sides and the coating film is a hardened coating film of a melamine resin.
Claim 17
Dependent Claim
104 words
A process for producing an optical recording medium which comprises forming a film of MgF 2 or CaF 2 on the inner surface of a casting mold by an ion-plating method, a spattering method or a vacuum-deposition method, casting into the mold an epoxy resin composition comprising an alicyclic epoxy resin or a mixture of a major amount of an alicyclic epoxy resin and a minor amount of an aromatic epoxy resin, an organic polybasic acid anhydride, a curing accelerator and an anti-discoloring agent, and then heat-curing the epoxy resin composition to obtain a transparent substrate, and applying an information-recording layer onto the substrate.
Claim 18
Dependent Claim
104 words
A process for producing an optical recording medium which comprises forming a film of MgF 2 or CaF 2 on the inner surface of a casting mold by an ion-plating method, a spattering method or a vacuum-deposition method, casting into the mold an epoxy resin composition comprising an alicyclic epoxy resin or a mixture of a major amount of an alicyclic epoxy resin and a minor amount of an aromatic epoxy resin, an organic polybasic acid anhydride, a curing accelerator and an anti-discoloring agent, and then heat-curing the epoxy resin composition to obtain a transparent substrate, and applying an information-recording layer onto the substrate.
Claim 19
Dependent Claim
93 words
A process for producing an optical recording medium, which comprises forming a film of SiC on the inner surface of a casting mold by a spattering method or a reactive vacuum-deposition method, casting an epoxy resin composition comprising an alicyclic epoxy resin or a mixture of a major amount of an alicyclic epoxy resin and a minor amount of an aromatic epoxy resin, an organic polybasic acid anhydride, a curing accelerator and an anti-discoloring agent, curing the epoxy resin composition to obtain a transparent substrate, and applying an information-recording layer onto the substrate.
Claim 20
Dependent Claim
93 words
A process for producing an optical recording medium, which comprises forming a film of SiC on the inner surface of a casting mold by a spattering method or a reactive vacuum-deposition method, casting an epoxy resin composition comprising an alicyclic epoxy resin or a mixture of a major amount of an alicyclic epoxy resin and a minor amount of an aromatic epoxy resin, an organic polybasic acid anhydride, a curing accelerator and an anti-discoloring agent, curing the epoxy resin composition to obtain a transparent substrate, and applying an information-recording layer onto the substrate.
Claim 21
Dependent Claim
119 words
A process for producing an optical recording medium, which comprises coating at least one inner surface of a casting mold with a radiation-curable resin or a thermosetting resin, curing the resin to form a coating film on the inner surface of the mold, casting into the mold an epoxy resin composition comprising an alicyclic epoxy resin or a mixture of a major amount of an alicyclic epoxy resin and a minor amount of an aromatic epoxy resin, an organic polybasic acid anhydride, a curing accelerator and an anti-discoloring agent, heat-curing the epoxy resin composition, thereby transferring the coating film to the resulting substrate, and applying an information-recording layer to the surface of the resulting two-layer or three-layer cast laminate.
Claim 22
Dependent Claim
119 words
A process for producing an optical recording medium, which comprises coating at least one inner surface of a casting mold with a radiation-curable resin or a thermosetting resin, curing the resin to form a coating film on the inner surface of the mold, casting into the mold an epoxy resin composition comprising an alicyclic epoxy resin or a mixture of a major amount of an alicyclic epoxy resin and a minor amount of an aromatic epoxy resin, an organic polybasic acid anhydride, a curing accelerator and an anti-discoloring agent, heat-curing the epoxy resin composition, thereby transferring the coating film to the resulting substrate, and applying an information-recording layer to the surface of the resulting two-layer or three-layer cast laminate.
Claim 23
Dependent Claim
28 words
A process according to Claim 17, wherein the casting mold has a releasing film bonded to the inner surface before coating it with the radiation-curable or thermosetting resin.
Claim 24
Dependent Claim
16 words
A process according to Claim 17, wherein the casting mold is free from a releasing film.
Claim 25
Dependent Claim
24 words
A process according to Claim 17, wherein two inner surfaces of the casting mold are coated with one kind of radiation-curable or thermosetting resin.
Claim 26
Dependent Claim
24 words
A process according to Claim 17, wherein two inner surfaces of the casting mold are coated with different kinds of radiation-curable or thermosetting resins.
References Cited (Backward Citations)
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