JPS62134836A - Manufacture of aluminum-resin composite substrate for optical magnetic disk with guide groove - Google Patents

Abstract

PURPOSE:To easily obtain an aluminum-resin composite substrate at a moderate cost by irradiating ultraviolet rays from a master disk and transferring a guide groove on an aluminum disk. CONSTITUTION:The Al disk is previously made at a coarseness of 10mum or below in terms of its surface. Then a silane coupling agent is applied to the Al disk as an adhesion improving agent to form a coupling layer. Next, an ultraviolet curing liquid resin is flowed on the Al disk, and the master disk made of a resin transmitting ultraviolet rays is compressed. When ultraviolet rays are irradiated from the master disk side to cure the ultraviolet curing liquid resin, the guide groove installed on the master disk is transferred. Thus the Al-resin composite substrate can be easily obtained at a moderate cost.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing an aluminum-resin composite substrate for optical/magnetic disks, which has excellent mechanical properties and is inexpensive and easy.

[Prior art]

Conventionally, substrates for optical/magnetic disks have been mainly made of glass or plastic. However, with the increasing density of storage capacity, high speed rotation and high accessibility have become important.Under such conditions, glass substrates are advantageous in preventing surface runout, warping, etc., but they are easily damaged when rotating at high speeds exceeding aooorpm. It is a danger.

Although plastic substrates can deal with these damages, they are not suitable for practical use because of the effects of surface runout, warpage, etc.

As a solution to these problems, metal substrates, particularly aluminum, have been used.

Products using aluminum have been announced in which a carbon layer is formed as an anti-reflection layer on an aluminum disk and a functional film is added to the entire group, but the manufacturing method for these is not specified at all. I don't have it.

Grooves can be added to optical/magnetic disk substrates by cutting the obtained substrate directly using a laser beam, or by using a grooved nickel master disk to transfer the grooves onto the substrate. Methods have been taken to do so. The method of directly cutting the substrate requires a complicated process and is not suitable for mass production.

On the other hand, the 7-otoborimer method (hereinafter referred to as the 2P method) is generally used for the transfer method, but when using an aluminum disc, the 2P method is used because both the aluminum disc and the nickel master disc are metal plates and are opaque. The formation of groove transcription was inconceivable.

[Purpose of the Invention] The present invention has been made by intensive investigation into a method for easily obtaining an optical/magnetic disk substrate having a guide groove that can withstand high speed rotation and has excellent accessibility, and in particular, an aluminum substrate having a guide groove. - We have discovered a method to easily obtain a resin composite substrate by using a plastic master, which was previously unthinkable.

[Structure of the invention]

The present invention involves casting ultraviolet-curable liquid resin gold onto an aluminum disk, having guide grooves on the resin, arranging a master disk made of a resin that transmits ultraviolet light so that the guide grooves face each other, and iron-pressing the resin. ,
An optical device having a guide groove, characterized in that an ultraviolet curable liquid resin is completely cured by irradiating ultraviolet light from the master side, and a guide groove made of the resin is transferred and formed on an aluminum disk.
This is a method of manufacturing an aluminum-resin composite substrate for magnetic disks.

The surface of the aluminum disk used in the present invention is roughened by wet or dry honing, chemical etching, etc. in order to improve adhesion to the ultraviolet curable resin.

The surface roughness is determined depending on the thickness of the ultraviolet curable resin layer. The thickness of the resin layer used in aluminum-resin composite substrates for optical/magnetic disks is often 50μ or less, and the surface roughness of the aluminum disk is at most 10μ or less.
Yes. If it is 10μ or more, there is a tendency for shadows of the roughened surface of the unevenness on the aluminum disk to appear on the surface of the resin layer (2P layer).

A silane cassilling agent is applied as an adhesion improver to the roughened surface of the aluminum disk by a known method, and a coupling layer is formed on the surface, preferably by heat treatment.

The coupling agent used here is a silane compound containing an unsaturated functional group such as vinyl silane, and the casting agent is a lower alcohol such as ethanol or insolononol. An ultraviolet curing liquid resin is cast onto the thus surface-treated aluminum disk.

As the ultraviolet curable liquid resin, for example, an ultraviolet curable resin system in which oligomers such as epoxy acrylate, urethane acrylate, daryester acrylate, and daryether acrylate are dissolved in a polyfunctional acrylate monomer is preferably used.

The photoinitiator is preferably a photoinitiator with good sensitivity in a relatively long wavelength range, such as 2,2-dimethoxy-2-7enylacetophenone or benzoin isobutyl ether, or a combination thereof. Furthermore, stabilizers, discoloration inhibitors, leveling agents, etc. may be added to the ultraviolet curable resin system, if necessary.

Note that it is desirable that the ultraviolet curable liquid resin has good releasability from the master used in the next step.

Next, an ultraviolet-curable liquid resin is cast onto an aluminum disk, and a master disk made of a resin that has guide grooves and transmits ultraviolet light is pressed with iron. A master disc made of a resin having guide grooves and transmitting ultraviolet light can be easily obtained by an injection method.

The resin forming the master disc may be of any material as long as it transmits ultraviolet light, does not meet the strict conditions of low birefringence used in optical discs, and has excellent appearance, groove transferability, and dimensional accuracy. It is desirable that the material has good removability and is compatible with the ultraviolet curable liquid resin used. %, jelly carbonate and lrimethic acrylate, which have a proven track record in optical discs, etc., are used.

Further, after the master is pressed with iron and pressed, ultraviolet rays are irradiated from the master side to harden the ultraviolet curing liquid resin and transfer the guide grooves.

[Effects of the Invention] The method of the present invention makes it possible to transfer guide grooves onto an aluminum disk by irradiating ultraviolet rays from the master side, which was previously unthinkable, and makes it possible to easily obtain aluminum-resin composite substrates at low cost. I can do it.

〔Example〕

The surface of a 51/4-inch aluminum disk is roughened by dry honing to a maximum surface roughness Rmax<10 prn.

Next, a silane coupling agent consisting of γ-methacryloxysolopyltrimethoxysilane/ethanol 1/8 (parts by weight) is applied to the disk by a dipping method, and the disk is heated at 100° C. for 1 hour.

After cleaning the surface with acetone, apply Aix Acrylate 60.
Parts by weight, trimethylolprozine triacrylate) 40
Part by weight and as photosensitizer benzoin methyl ether 3
A UV-curable liquid resin consisting of parts by weight was cast and applied, and then a grooved master disk made of jellycarbonate was pressed and cured by irradiating with a high-pressure mercury lamp (SOW) from a height of 15α for 30 minutes. The resulting Al-ξ-resin composite substrate for optical/magnetic disks having guide grooves had a resin layer having a thickness of 30 μm.

Furthermore, the guide grooves transferred onto the aluminum disk had a transfer rate of 90 inches or more, making it an excellent substrate for SB optical/magnetic disks.

Claims (3)

[Claims] (1) Casting ultraviolet curable liquid resin onto an aluminum disk,
A master disk made of a resin that has guide grooves on the resin and is transparent to ultraviolet light is arranged so that the guide grooves face each other, and is pressed with scissors, and ultraviolet light is irradiated from the master side to form an ultraviolet curable liquid resin. A method for manufacturing an aluminum-resin composite substrate for optical/magnetic disks having guide grooves, which comprises hardening and transferring guide grooves made of the resin onto an aluminum disk. (2) A light beam having guide grooves according to claim 1, which uses an aluminum disk whose surface on which the ultraviolet curable liquid resin is cast is treated with a silane coupling agent having an ethylenic double bond. A method for manufacturing an aluminum-resin composite substrate for magnetic disks. (3) Claim 1, in which the master disk made of a resin having guide grooves and transmitting ultraviolet light is made of polycarbonate or polymethyl methacrylate obtained by injection molding.
A method for manufacturing an aluminum-resin composite substrate for optical/magnetic disks having a guide groove as described in 2.