JPS58108042A - Disc type recording carrier - Google Patents

Abstract

PURPOSE:To prevent deformation at high temp. and high humidity by laminating an UV curing resin layer having pits corresponding to information on a transparent substrate consisting of a thermosetting resin to form a disc and specifying the respective curable resins. CONSTITUTION:An UV curing resin layer 3 having pits 1 corresponding to information signals, a metallic layer 4 and a plastic protective layer 5 are laminated successively on a transparent plate 2 consisting of a thermosetting resin having network structure, whereby a disc type recording medium is formed. In this case, a resin contg. bi- or higher functional methacrylate or dially ester of org. dicarboxylic acid as one component is used as a thermosetting resin for the plate 2. Epoxy acrylate or the like obtd. by reaction of an epoxy resin with acrylic acid is used for the layer 3. These resins form the disc type recording medium of high quality which does not deform when exposed to high temp. and high humidity.

Description

[Detailed description of the invention] The present invention is an optical POM audio disc.

This relates to disc-shaped record carriers used for optical video discs, etc. In particular, when these disc-shaped record carriers are manufactured from stampers obtained from master discs by electroforming, etc., the information signals applied to the stampers are extremely sensitive. The object of the present invention is to provide an extremely high-quality disk-type record carrier that has a faithful surface structure and does not undergo deformation such as warping even when exposed to high temperature or high humidity.

In the field of the record industry, in order to obtain discs, for example, disc records are produced by hot compression molding of a copolymer of vinyl chloride and vinyl acetate, using a stamper whose surface is coated with information signals. ing. However, for example in a video disc with a high density information signal,
Since the information signal has a microstructure, there is a problem in that a good reproduction signal cannot be obtained due to inaccuracy in molding.

In addition, in recent years, optical video discs have been released that are made by compressing or injection molding methacrylic resin and then providing a vapor-deposited metal layer and a protective layer, but since methacrylic resin is a thermoplastic resin, there are restrictions on the operating temperature range, especially the upper limit. However, since it does not yet have a mesh structure, it is prone to warping due to moisture absorption.For this reason, the upper limit of the operating temperature range is higher, and it is better to use methacrylic resin instead of polycarbonate resin, which has less moisture absorption. Attempts have been made to replace this with discs, but the reality is that it is extremely difficult to mold optically uniform discs free of optical distortion.

Therefore, there is a strong demand for a disk-type record carrier having a signal faithful to the information signal applied to the stamper. In addition, there is a strong demand for a disk-type record carrier that does not undergo deformation such as warpage and can be used under any environment. Furthermore, from a production standpoint, it is necessary that the disc be easily peeled off from the stamper after it is manufactured, that is, it must not have adhesiveness to the stamper.

The present invention provides a disk-type record carrier that satisfies such demands, and is characterized by using a transparent plate made of a thermosetting resin having a network structure as a support, and having a transparent plate on one side of the support. It is constructed by sequentially laminating an ultraviolet curing resin layer, a metal layer, and a resin protective layer each having pits corresponding to at least an information signal.

In manufacturing the disk-type record carrier of the present invention, first, a part or the entire surface of the stamper on which the information signal has been applied is coated with a liquid resin that can be cured by irradiation with ultraviolet rays, and then a liquid resin that can be cured by heat curing is applied. The obtained support made of a thermosetting transparent plate having a network structure is pressed to make the liquid resin have a uniform thickness. The liquid resin is then cured by irradiating ultraviolet light through the support.
Thereafter, the support is peeled off from the stamper together with the cured resin adhered thereto to obtain a disk. If the resulting disc is to be used as an optical video disc or an optical audio disc, a reflective layer of metal, e.g. aluminum, is provided by vacuum deposition on the surface with pits corresponding to the information signals, and a plastic protective layer is applied thereon. The layer can be applied by spray coating or the like to obtain a single-sided disc-shaped record carrier. It goes without saying that a double-sided disk-type record carrier can be obtained by bonding the plastic protective layer surfaces of the disk-type record carrier thus obtained together with a suitable adhesive.

A transparent plate made of a thermosetting resin having a network structure must have appropriate transparency in the ultraviolet region around 366 mμ, and when optically reading information signals from the obtained disk-shaped record carrier, it is necessary to Especially He-Ha
Excellent transparency to laser light or semiconductor laser light is required. In order to satisfy these demands,
The material for the transparent plate is preferably a thermosetting resin obtained by using a trifunctional or higher functional methacrylic acid ester or diallyl ester of an organic dicarboxylic acid as one component. Examples of trifunctional or higher functional methacrylic acid esters include ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, and trimethylolpropane trimethacrylate. Examples of diallyl esters of organic dicarboxylic acids include diallyl maleate and diallyl. Examples include phthalates.

In order to obtain a transparent plate made of a thermosetting resin having a network structure, an appropriate amount of a monofunctional vinyl monomer such as methyl methacrylate or diethylene glycol methacrylate monomethyl ether is mixed with the trifunctional or higher functional methacrylic ester or diallyl ester. and dissolve a thermosetting catalyst such as an organic peroxide. This is 11W! When poured between flat glass plates equipped with E-thick gaskets and left at a predetermined temperature for a certain period of time, polymerization occurs and the desired transparent plate is obtained.

For example, 1. Mix 2% by weight of methyl ethyl ketone peroxide with a mixture of neopentyl glycol dimethacrylate and diethylene glycol methacrylate monomethyl ether, pour the resulting clear solution between glass plates, and heat at 70°C for 5 hours.

The desired transparent plate is obtained by heating at 115° C. for 2 hours. This can be cut into an appropriate shape. By using the sheet made of thermosetting resin with a network structure obtained in this way as a transparent plate, deformation such as warping does not occur even when left under harsh conditions, and a high-quality disk-shaped record carrier can be produced. was found to be obtained.

An example of a liquid resin that can be cured by ultraviolet irradiation is one containing 2,2-bis(4-acryloyloxypolyethyleneoxyphenyl)propane represented by the following structural formula, (30@0H=CH2 (However, m and n are integers, and the sum of m and n is 3 to 4.) Furthermore, other typical examples include epoxy acrylate obtained by the reaction of epoxy resin and acrylic acid, N-
It substantially contains either vinylpyrrolidone or tetrahydrofurfuryl acrylate, or both, and a photopolymerization initiator, and by using this material, it has excellent releasability from the stamper and also has excellent removability from the stamper surface. - A disk is obtained which has a surface structure that is extremely faithful to the information signal applied to it.

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a partially enlarged plan view of a record carrier for an optical video disc, and FIG. 2 is a sectional view taken along the line X--X/. The disk-type record carrier having the structure shown in the figure is made of a thermosetting resin having a network structure obtained by containing at least a difunctional or higher-functional methacrylic acid ester or a diallyl ester of an organic dicarboxylic acid as one component, or an adhesive layer is provided on the surface. A transparent plate 2 made of the above resin and pits 1 corresponding to the axis signals are provided. As the ultraviolet curable resin, one containing 100 parts by weight of 2,2-bis(4-acryloyloxydiethyleneoxyphenyl)furopane, 2 parts by weight of benzyl and 1.6 parts by weight of P-dimethylaminobenzaldehyde, or bisphenol A type. It contains 60 parts by weight of epoxy acrylate obtained by the reaction of epoxy resin and acrylic acid, 40 parts by weight of N-vinylpyrrolidone, and 3 parts by weight of benzoin isobutyl ether.
be. Note that, in order to modify the properties of the resin layer 3, various additives can be added to the liquid resin that is cured by ultraviolet rays. For example, defoaming properties of liquid resin, stamper
Surfactants such as defoamers and wetting agents to improve wetting with the material, non-reactive thermoplastic resins to reduce curing shrinkage, and effective use of the heat generated from the lamp during ultraviolet irradiation. There are thermosetting catalysts such as organic peroxides.

After curing with ultraviolet rays, a metal layer for reflecting and reflecting laser light is formed by vacuum-depositing aluminum on the surface of the disk obtained by peeling it off from the stand bar.4. A plastic protective layer 6 obtained by coating with acrylic paint is then successively knotted.

Furthermore, in the above-described structure, by bonding the plastic protective layer surfaces together with a suitable adhesive, an optical video disc capable of double-sided playback can be obtained.

As is clear from the above description, according to the present invention, extremely fine pits can be obtained with high accuracy by forming pits in the ultraviolet curable resin layer. Also,
In contrast to conventional disks manufactured by compression or injection molding of methacrylic resin, which is a thermoplastic resin, the disk-shaped record carrier of the present invention has a transparent plate support made of a thermosetting resin having a network structure. Because of this, it is of extremely high quality and will not warp or otherwise deform even if left in high temperature or high humidity conditions.

In the above description, a disc-shaped record carrier suitable for use in optical video recording, 1-toku, etc. has been described in detail, but after being peeled off from the stamper, for example If a metal electrode such as silver is provided as a thin layer by vacuum evaporation or the like, and then a plastic dielectric layer and an oil layer are sequentially provided on top of this to form a disk-shaped record carrier, it can also be used as a capacitive video disk. It is possible.

[Brief explanation of the drawing]

FIG. 1 is a partially enlarged plan view showing an embodiment of a disk-type record carrier according to the present invention, and FIG. 2 is a sectional view thereof taken along the line XXZ. 1... Pit corresponding to the information signal, 2...
...Transparent plate made of thermosetting resin, 3...
・Ultraviolet curable resin layer, 4...Metal layer, 6...
...Plastic protective layer.

Claims (1)

[Scope of Claims] (1) A transparent plate made of a thermosetting resin having a network structure is used as a support, and on one side of the transparent plate, an ultraviolet curable resin layer, a metal layer, and a resin protective layer have at least pits corresponding to information signals. are sequentially laminated, and by arranging pits corresponding to the information signals in a spiral or concentric pattern, spiral or concentric recording traces are formed at predetermined intervals. A disc-type record carrier characterized by: ? ) The transparent plate made of a thermosetting resin having a network structure is made of a thermosetting resin obtained by using as one component a di- or higher-functional methacrylic acid ester or a diallyl ester of an organic dicarboxylic acid, or the above-mentioned film having an adhesive layer on its surface. A disk-type record carrier according to claim 1, characterized in that it is made of resin. (3) The ultraviolet curable resin layer contains 2,2-bis(4-acryloyloxypolyethyleneoxyphenyl)propane represented by the structural formula % (where m and n are integers and the sum of m and n is 3 to 4). (4) The ultraviolet curable resin layer obtained by curing the resin composition containing at least one of epoxy acrylate, N-vinylpyrrolidone, or tetrahydrofurfuryl acrylate obtained by the reaction of an epoxy resin and acrylic acid. The disk-shaped record carrier according to claim 0), which is obtained by curing a resin composition composed of one or both of them and a photopolymerization initiator. (6) It is characterized in that it is constructed by preparing two laminates consisting of a transparent plate, an ultraviolet curing resin layer, a metal layer and a resin protective layer, and pasting together the resin protective surfaces of the two laminates. Claims paragraphs (1), @), and (3)
) or (4).