JPS61283048A - Production of thin-type disk - Google Patents

Abstract

PURPOSE:To obtain stably the title thin flexible disk by laminating a resin having a low heat-deflection temp. on one or both surfaces of a heat-resistant sheet directly or through another layer, heating and compressing the resinous layer to transfer a rugged signal to the layer and cooling and curing the resin. CONSTITUTION:A soln. in toluene of polymethyl methacrylate having 85 deg.C heat-deflection temp. and 80000 number average mol.wt. is uniformly coated on a polyimide film 8 having >=300 deg.C heat-deflection temp. and 25mum thickness. The film8 is dried at 100 deg.C to laminate a polymethyl methacrylate layer 7 having about 50mum thickness. A stamper 4 molded from an original disk by electrocasting is fixed to a metallic mold 2, a cushion 5 is fixed to a metallic mold 3 and the laminate is heated and compressed to transfer a rugged signal to the layer 7. The laminate is then cooled and cured. A disk is stamped 6 and the remaining material is wound. By this constitution, a flexible disk having <=1mm thickness can be stably obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a disk, and particularly to a method for manufacturing a thin high-density information recording disk such as a flexible video disk and a grooved optical information recording substrate.

[Conventional technology]

Conventional high-density information recording disks are made of thermoplastic resin such as polymethyl methacrylate or polycarbonate, with uneven signals on the surface.

It is manufactured by injection molding or compression molding, followed by cooling and solidification.

With this method, it is difficult to make the film thin, and the thickness is 1.0mm.
It was difficult to stably manufacture the following discs.

[Purpose of the invention]

The present invention has been made in view of the above problems, and its purpose is to provide a method for stably manufacturing flexible disks and the like having a thickness of 1.0+u+ or less.

[Means to solve the problem]

The above object of the present invention is to laminate a resin having a lower heat deformation temperature than the heat resistant sheet on one or both sides of a heat resistant sheet directly or through another layer, and to press the resulting laminate sheet under heat. This is achieved by a method in which a concavo-convex signal is transferred onto the surface of the resin layer, and then cooled and solidified.

In the present invention, the method of laminating the resin on the heat-resistant sheet includes a method of dissolving the resin in a solvent etc. and applying it to the heat-resistant sheet by roll coating, a method of forming the resin into a film form and laminating it on the heat-resistant sheet, etc. There is. If an adhesive layer is provided between the resin and the heat-resistant sheet, even greater adhesive strength can be obtained, and the heat-resistant sheet is protected by the adhesive layer.

A sheet in which a resin is laminated on a heat-resistant sheet is heated and pressed, and an uneven signal is transferred to the surface of the resin layer of the sheet.

After the above transfer process, a thin disk is obtained through cooling and solidification.Thin disks with resin layers on both sides have a large amount of information per disk, are economical, and have a symmetrical shape on the front and back. Therefore, the thin disk itself has the advantage of less deflection.

Further, in the present invention, if the thin disk onto which the uneven signal is transferred is subjected to post-processing such as metal vapor deposition or coating with a light-absorbing dye, a disk that can be used in an optically configurable system can be obtained.

The heat-resistant sheet, that is, the heat-resistant base film used in the present invention is one that can withstand the temperature of the resin in a plastic state during formation of the uneven pattern, and is preferably a thermosetting heat-resistant film.
Typical examples of this thermosetting heat-resistant film include polyimide film, polyamideimide film, epoxy resin film, silicone resin film, polyesterimide film, polyester film, tetrafluoroethylene-hexafluoropropylene copolymer film, and tetrafluoroethylene-hexafluoropropylene copolymer film. Examples include fluororesin films such as fluoroethylene rubber fluoroalkyl vinyl ether copolymer films.

Thermoplastic resins are preferred as the resin that forms the uneven pattern on the surface used in the present invention. Typical thermoplastic resins include polysulfone, polyolefin, ethylene-vinyl acetate copolymer, and ethylene-acrylate copolymer. and polyolefin copolymers such as ethylene-propylene copolymers, polyolefin halides, vinyl chloride copolymers such as vinyl acetate-vinyl chloride copolymers and vinyl chloride-acrylonitrile copolymers, and vinylidene chloride-vinyl chloride copolymers. vinylidene chloride copolymers such as vinylidene chloride-vinyl chloride-acrylonitrile copolymers, polystyrene, styrene-acrylonitrile copolymers (A
S resin), styrene copolymers such as styrene-acrylonitrile-butadiene copolymer (AB!J resin), p-methylstyrene, 2,5-dichlorostyrene, vinylanthracene, etc., or their copolymers ( styrene copolymer), coumaron and indene or their copolymers with styrene, terpene resin or picolite, acrylic resin, polyacrylonitrile, acrylonitrile-vinyl acetate copolymer, acrylonitrile-vinylpyridine copolymer, acrylic Acrylic nitrile copolymers such as nitrile-methyl methacrylate copolymers, polyacrylamide, dia-7ton acrylamide polymers made by reacting acrylonitrile with acetone, polyvinyl acetate, acrylic esters, vinyl esters, vinyl ethers, ethylene, etc. copolymer with vinyl acetate,
Polyvinyl ether, polyamide, thermoplastic polyester, polyvinyl alcohol or polyvinyl acetal resin, polyurethane, polyvinyl carbazole having a number average molecular weight of e, ooo or less, or a polyvinyl carbazole copolymer of vinyl carbazole and ethylene or styrene, etc. Nitrogen-containing vinyl polymers, polybutadiene or diene polymers such as butadiene-styrene copolymers and isoprene-isobutylene copolymers, polyethers, polybonates, polyethyleneimines, cellulose resins, or two of the above resins. There are blends of the above materials and blends with other thermoplastic resin plates.

〔Effect of the invention〕

As described above, a resin having a lower heat deformation temperature than the heat-resistant sheet is laminated on one or both sides of the heat-resistant sheet, directly or through another layer, and the resulting laminated sheet is heated and pressed, and the resin is By transferring uneven signals to the layer and then cooling and solidifying it, flexible disks and the like with a thickness of 1.0 mm or less can be stably manufactured.

〔Example〕

Hereinafter, specific embodiments of the present invention will be shown based on FIGS. 1.2.3 and 4, and the present invention will be explained in further detail.

Example 1 Polymethyl methacrylate having a heat distortion temperature of 85°C and a number average molecular weight of 80,000 was dissolved in toluene, and the solution was used to form a polyimide film 8 with a heat distortion temperature of 300°C or higher and a thickness of 25 tiles in FIG. (Kapton film from Azuma) by roll coating to a uniform thickness. When the polyimide film 8 coated with the solution is heated and dried at 100°C for 1 hour, the film becomes 50% thick after the toluene has evaporated.
The polymethyl methacrylate layer 7 of u remained, and a laminated sheet 1 was obtained. In FIG. 2, as a press part, a stamper 4 manufactured by electroforming from a master was attached to a mold 2, and a cushion layer 5 was attached to a mold 3. The laminated sheet 1 was heated and pressed in the press section to transfer the concave and convex signals to the polymethyl methacrylate layer 7, then cooled and solidified, and a disk with the concave and convex signals was punched out in the punching section 6. After punching out the sheet, I rolled it up.

Example 2 Polymethyl methacrylate having a heat distortion temperature of 85°C and a number average molecular weight of 80,000 was dissolved in toluene, and the solution was used to form a polyimide film 16 with a heat distortion temperature of 300°C or higher and a thickness of 25 scales in FIG. (Kapton Film of East)
It was applied to both sides of the film to a uniform thickness by roll coating. When the polyimide film 1B coated with the solution is heated and dried at 100°C for 1 hour, the thickness becomes 5.
A 0u polymethyl methacrylate layer 7 remained on both sides of the polyimide film IB, and a laminated sheet 9 was obtained. In FIG. 4, stampers 12 and 13 manufactured by electroforming from a master are used as press parts in molds 10 and 11, respectively.
I was attached to it. The laminated sheet 9 was heated and pressed in the press section to transfer the concave and convex signal bands to both polymethyl methacrylate layers 15, then cooled and solidified, and a disk with the concave and convex signals was punched out in the punching section 14. . After punching out the sheet, I rolled it up.

[Brief explanation of drawings]

Figures 1 and 3 are cross-sectional views of sheets made of polyimide film laminated with polymethyl methacrylate;
FIG. 4 is a cross-sectional view of an apparatus that transfers a concavo-convex signal to the laminated sheet and punches out a finished disk. 1.9: Laminated sheet 2.3, 10, 11: Mold 4, 12.137 Stamper 5: Cushion layer 6.14: Punching section 7.15: Polymethyl methacrylate 8.18: Polyimide film Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1) A resin having a lower heat distortion temperature than the heat-resistant sheet is laminated on one or both sides of a heat-resistant sheet, either directly or via another layer, and the resulting laminated sheet is pressed under heat. A method for manufacturing a thin disk, characterized in that after transferring a concavo-convex signal to the surface of the resin layer, the resin layer is cooled and solidified. 2) The method for manufacturing a thin disk according to claim 1, wherein the resin layer is made of a thermoplastic resin. 3) The method for manufacturing a thin disk according to claim 1 or 2, wherein the heat-resistant sheet is made of a thermosetting resin.