JPH08263878A - Optical disk and its production - Google Patents

Abstract

PURPOSE: To prevent scratches and deposition of dust on an optical disk and to improve reliability as a recording medium by adding scratching resistance and antistatic effect to the surface of a synthetic resin substrate of an optical disk so that these effects are permanent. CONSTITUTION: After a compd. having alkoxysilyl groups or silanol groups is applied on the surface of a synthetic resin substrate of an optical disk, the substrate is left to stand at normal temp. for a desired time or heated at between >=30 deg.C and <=150 deg.C for a desired time. By this method, the formed film contains a siloxane mesh structure having silanol groups and is firmly adhered to the substrate surface by an anchor effect.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of an optical disk such as a magneto-optical disk, a phase change type optical disk, a compact disk (CD), etc. in which recorded information is reproduced by an optical means, and in particular, the surface of the disk is electrically charged. The present invention relates to an optical disc and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a substrate of an optical disk such as a magneto-optical disk, a phase change type optical disk, a compact disk (CD), etc., which reproduces recorded information by an optical means is a polycarbonate, a polymethylmethacrylate, an amorphous polyolefin. And other synthetic resin substrates are used.

These resins have the characteristics of being optically homogeneous and highly transparent, and being excellent in moldability and mechanical strength, but have low surface hardness and are easily scratched on the substrate surface. Therefore, there is a drawback that an error is likely to occur when reproducing or recording the information.

Further, since the synthetic resin substrate is easily charged and dust such as dust or dust is easily adsorbed on its surface, there is a drawback that an error is likely to occur at the time of reproducing or recording information.

In order to solve such a problem, a surface protective coating agent has been developed which protects the substrate surface by applying a resin composition which is cured by ultraviolet rays onto a synthetic resin substrate and curing it. . Furthermore, a method has been implemented in which an antistatic agent is mixed into a protective coating agent, and the antistatic agent is applied onto a substrate and cured to prevent the substrate from being charged.

The expression of the antistatic ability in the above method of mixing the antistatic agent in the protective coating agent is due to the bleeding of the antistatic agent on the cured surface of the substrate,
If excessive antistatic agent oozes out on the surface of the substrate during long-term use, it may cause an error when reproducing or recording information.Therefore, the amount of antistatic agent added depends on the surface condition of the substrate. Need to be limited to a level that does not disturb,
Therefore, this method has a problem that the effect of preventing the adsorption of dust such as dust and dust cannot be sufficiently obtained.

[0007]

DISCLOSURE OF THE INVENTION The present invention provides an optical disk having excellent scratch resistance on the surface of a substrate and having an antistatic ability for preventing adhesion of dust without causing bleeding of an antistatic agent on the surface of the substrate. The purpose is to provide.

[0008]

In order to solve the above problems, the present inventor has conducted diligent studies, and as a result, applied a compound having an alkoxysilyl group or a silanol group to the substrate surface on the reading surface side of an optical disk. Then, it was found that scratch resistance and antistatic ability can be permanently imparted to the surface of the substrate by leaving it for a predetermined time after coating or by heating it at a predetermined temperature for a predetermined time, and the present invention has been completed. .

That is, the optical disk of the present invention is an optical disk using a transparent synthetic resin substrate, characterized in that a film containing a siloxane network having a silanol group is formed on the substrate surface on the reading surface side of the optical disk. Is.

The optical disc manufacturing method of the present invention is
A method of manufacturing an optical disc using a transparent synthetic resin substrate is characterized by including a step of applying a compound having an alkoxysilyl group or a silanol group to the substrate surface on the reading surface side of the optical disc.

Further, the method for producing an optical disc of the present invention is the method for producing an optical disc using a transparent synthetic resin substrate, wherein silicon tetrachloride is partially hydrolyzed in alcohol on the substrate surface on the reading side of the optical disc. It is characterized by having a step of applying an object.

In the present invention, the surface on the side on which the laser light is incident upon irradiating the laser light to reproduce the recorded information is referred to as the reading surface of the optical disk.

The resin used as the material of the substrate of the optical disk in the present invention is a material that does not undergo deformation such as shape change or physical property change due to operating temperature and humidity of optical disks such as magneto-optical disks, phase change type optical disks and compact disks (CD). However, it is not particularly limited, and examples thereof include polycarbonate resin, acrylic resin, polyolefin resin, and the like.

The compounds having an alkoxysilyl group or silanol group in the present invention include vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane and γ.
-Glycidoxypropyltrimethoxysilane, β-
(3,4 epoxycyclohexyl) ethyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, Alkoxysilanes commonly called silane coupling agents such as N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane and γ-chloropropyltrimethoxysilane, and a portion of silicon tetrachloride in alcohol. Hydrolyzate and the like are exemplified. A surface treatment agent containing a partial hydrolyzate of silicon tetrachloride in alcohol as a main component is commercially available as Colcoat (registered trademark) from Colcoat Co., Ltd. This surface treatment agent can be used as a partial hydrolyzate in alcohol.

The above compounds in the present invention are usually used as an alcohol solution or an aqueous solution of methanol, ethanol, isopropanol and the like. Although the concentration of these solutions varies depending on the coating method, it is generally 0.1 to 1
It is used as a 0 vol%, more preferably 0.5 to 5 vol% solution.

The coating method of the above-mentioned compound or surface treatment agent in the present invention includes spin coating, spray coating,
The coating method is not particularly limited as long as it is a coating method used in ordinary resin coating, such as dipping or brush coating.

After the above compound or surface treatment agent is applied to the surface of the substrate, it is allowed to stand at room temperature for an arbitrary time, or at a temperature of 30 ° C to 150 ° C, more preferably 50 ° C to 100 ° C for any time, By heating, a coating film containing a siloxane network having silanol groups can be formed on the surface of the substrate. This siloxane network with silanol groups has hygroscopicity and strongly adheres to the surface of the substrate due to the anchoring effect, so it gives the substrate surface scratch resistance similar to that of glass, and also protects the substrate surface from charging. It becomes possible to retain the preventive ability permanently.

[0018]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

(Example 1) A surface treatment agent whose main component is a partial hydrolyzate of silicon tetrachloride in alcohol on the surface of a polycarbonate resin substrate for a 5.25-inch magneto-optical disk, a product of Colcoat Co., Ltd. Name "Colcoat N-
103X ”was spin-coated and heat-treated at 60 ° C. for 10 minutes.

After the treatment, the surface resistance of the substrate surface was measured and found to be 2.7 × 10 ⁹ Ω / □. The pencil hardness of this substrate was measured and found to be 2H.

Example 2 N-β (aminoethyl) γ-aminopropyltrimethoxysilane 2 was formed on the surface of a polycarbonate resin substrate for a 5.25-inch magneto-optical disk.
30% methanol solution by spray coating at 80 ℃
Heat treated for minutes.

After the treatment, the surface resistance of this shell was measured and found to be 5.3 × 10 ¹³ Ω / □. The pencil hardness of this substrate was measured and found to be H.

Comparative Example 1 The surface resistance of the polycarbonate resin substrate for a 5.25 inch magneto-optical disk was measured and found to be 10 ¹⁶ Ω or more. The pencil hardness of the substrate was measured and found to be 2B.

[0024]

As described above, according to the present invention, the substrate surface on the reading side of the optical disk is provided with scratch resistance similar to that of glass and the antistatic ability of the substrate surface is permanently retained. Since it is possible to prevent scratches and adhesion of dust on the surface of the optical disk permanently, it is possible to prevent the occurrence of an error at the time of reproducing or recording information, and improve the reliability as a recording medium. it can.

[0025]

Claims (3)

[Claims] 1. An optical disc using a transparent synthetic resin substrate, characterized in that a coating film containing a silanol group-containing siloxane network is formed on the substrate surface on the reading side of the optical disc. 2. A method of manufacturing an optical disk using a transparent synthetic resin substrate, comprising a step of applying a compound having an alkoxysilyl group or a silanol group to the surface of the substrate on the reading surface side of the optical disk. Optical disc manufacturing method. 3. A method of manufacturing an optical disk using a transparent synthetic resin substrate, comprising the step of applying a partial hydrolyzate of silicon tetrachloride in alcohol to the surface of the substrate on the reading surface side of the optical disk. A method for manufacturing a featured optical disc.