JPH07112593A - Method for manufacturing card-shaped optical recording medium - Google Patents

Abstract

(57) [Summary] [Problem] To provide a method for producing a card-shaped optical recording medium, which can prevent cracks from occurring, has good adhesion to a substrate, and has high flexibility. To do. [Structure] A transparent photocurable hard coat liquid is applied to the opposite side of the groove surface of the transparent substrate with the same solvent for 10 to 100 pp
A card-shaped optical recording medium, characterized in that it is washed with a diluting solution diluted to m, and a hard coat agent is applied on the washed surface with a slight amount of the diluting solution remaining and then photocured to form a hard coat layer. Method

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a card-shaped optical recording medium, and more particularly to a method for manufacturing an optical card having a hard coat.

[0002]

2. Description of the Related Art In recent years, with the progress of informationization in society, an information storage medium for recording or reproducing optical information such as an optical disk, an optical card, an optical tape, etc. as a means for efficiently handling a wide variety of information, and recording of information. Many playback devices have been proposed.

In the information storage medium, binarized information has a change in reflectance, a change in reflected light intensity due to a change in surface shape such as the presence or absence of pits (holes), and polarization due to a magneto-optical effect. There is one that can detect the change in the surface by converting it into the change in intensity. The characteristics of the information storage carrier described above are excellent in that it has a long recording life because of its high recording density and non-contact recording and reproduction.

Further, a card-shaped information storage carrier (hereinafter referred to as an optical card) which is excellent in portability and has a large capacity compared to its size has been actively researched and developed recently, and has been proposed. Have begun.

The optical card will be described below. Optical cards can be used as information carriers that can be carried by each individual, such as medical chart cards, credit cards, cash cards, bank cards, by taking advantage of their ability to record large amounts of information and their excellent portability. It is expected to be put to practical use in a wide variety of applications such as ID cards such as ID cards and driver's licenses.

However, since the optical card is an information storage carrier for optically recording / reproducing, a transparent substrate through which light passes,
And the defects on its surface are fatal, and in particular, since the card on which a large amount of personal information is recorded is carried and used, it is most concerned that the surface of the card will be scratched during carrying and it will not be reproducible. Has been done. For this reason, increasing the wear resistance of the surface of the transparent substrate is an indispensable development item, and many proposals have been made so far.

[0007] In the proposals so far, for example, Japanese Utility Model Laid-Open No. 54-
No. 179104, Japanese Utility Model Publication No. 60-37700,
As disclosed in Japanese Patent Laid-Open No. 63-23236, etc., it has been a mainstream to apply a resin dissolved in a solvent to a resin substrate and cure the resin to form a hard coat layer. Examples of this coating method include a roll coater coating method, a spinner coating method, and a dipping coating method.

On the other hand, as a dry method for providing a hard coat layer, as described in JP-A-62-129952,
There is also a type in which a transparent hard film (specifically, a glass thin film is suggested) is used for the hard coat.

[0009]

However, in the above-mentioned conventional example, regarding the adhesion to the substrate, particularly the adhesion of the hard coat layer to the polymethylmethacrylate substrate,
There was a problem that peeling is likely to occur.

Further, for a relatively soft substrate such as polycarbonate, it becomes necessary to thicken the hard coat layer in order to increase its hardness, but this results in poor adhesion and easy occurrence of cracks. There was also a problem.
Therefore, in order to improve the occurrence of cracks and adhesion, it is possible to apply a hard coat layer several times to make the hardness a gradient, but by increasing the number of layers, the number of production steps increases and the yield decreases, so There was a problem that it was costly.

[0011]

SUMMARY OF THE INVENTION The present invention is intended to solve the above problems, and its gist is a card-shaped optical recording medium in which a recording layer is formed on the groove surface of a transparent substrate and a protective layer is provided thereon. In the method for producing a transparent substrate, a hard coat liquid comprising a transparent photo-curable hard coat base material and a solvent is applied to the opposite side of the groove surface of the transparent substrate in an amount of 10 to 100 with the same solvent.
A card-shaped optical recording medium, characterized in that it is washed with a diluent diluted to ppm and a hard coat agent is applied on the cleaned surface with a slight amount of the diluent remaining, and then photocured to form a hard coat layer. A method for manufacturing a card-shaped optical recording medium, comprising a recording layer formed on the groove surface of a transparent substrate, and a protective layer provided on the recording layer, wherein a transparent photocurable type is provided on the opposite side of the groove surface of the transparent substrate. Hard coating solution consisting of hard coating main agent and solvent with the same solvent 10-100
After washing with diluted solution diluted to ppm, and leaving a trace amount of diluted solution on the washed surface, in an atmosphere of solvent vapor 60 ° C-80 ° C
After applying heat treatment for a predetermined time with a hard coat agent,
A method for producing a card-shaped optical recording medium is characterized by forming a hard coat layer by photo-curing.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

FIG. 1 is an explanatory view showing a typical example of a card-shaped optical recording medium obtained by the manufacturing method of the present invention. In FIG. 1, a card-shaped information storage medium obtained by the method of the present invention is provided with a hard coat layer 2 on the opposite side of the groove surface of a transparent substrate 1 having a pre-groove portion 1a on the surface thereof by the above-described manufacturing method. A recording layer 4 is formed on the groove portion 1a, and a back substrate 5 as a protective layer is bonded onto the recording layer 4 with an adhesive layer 6 interposed therebetween.

Next, FIGS. 2A to 2D are process diagrams showing an example of a method for manufacturing a card-shaped optical recording medium of the present invention.
In the figure, the opposite side of the groove surface of the transparent substrate 1 is washed with a diluting solution of 10 to 100 ppm prepared by diluting the hard coating solution with a solvent to leave a small amount of the diluting solution (FIG. 2).
(A)). Then, a hard coat liquid is applied and light 9 is irradiated (FIG. 2B). At this time, photocuring starts in a state where the interface between the transparent substrate 1 and the hard coat layer 2 is solvent-rich compared to the surface of the hard coat layer, so that the hardness of the hard coat layer 2 after curing has a gradient in the thickness direction. . Further, the interface between the diluting solution 7 and the hard coat agent 8 disappears during the photo-curing process, and the hard coat layer 2 is formed (FIG. 2).
(C)). The recording layer 4 is formed on the pre-groove portion 1a of the transparent substrate 1 on which the hard coat layer 2 is formed, and the back substrate 5 is attached onto the recording layer 4 with the adhesive layer 6 interposed therebetween to form a card-like optical recording. Media can be obtained (Fig. 2
(D)).

FIGS. 3A to 3E are process diagrams showing another example of the method for manufacturing a card-shaped optical recording medium of the present invention. In FIG. 3, the opposite side of the groove surface of the transparent substrate 1 is washed with a diluting solution having a concentration of 10 to 100 ppm, which is obtained by diluting the hard coating solution with a solvent, to leave a small amount of the diluting solution (FIG. 3).
(A)). This transparent substrate 1 is put in a constant temperature bath 11 filled with a solvent vapor 10 and heat-treated at 60 to 80 ° C. for 1 to 3 minutes (FIG. 3B). Next, a hard coat liquid is applied and irradiated with light 9 (FIG. 3 (c)). At this time, photocuring starts in a state where the interface between the transparent substrate 1 and the hard coat layer 2 is solvent-rich compared to the surface of the hard coat layer, so that the hardness of the hard coat layer 2 after curing has a gradient in the thickness direction. . Further, the interface between the diluting solution 7 and the hard coat agent 8 disappears during the photo-curing process, and the hard coat layer 2 is formed (FIG. 3 (d)). Next, the recording layer 4 is formed on the pre-groove portion 1a of the transparent substrate 1 on which the hard coat layer 2 is formed, and the back substrate 5 is bonded onto the recording layer 4 via the adhesive layer 6, A card-shaped optical recording medium is obtained. In the present invention, the hard coat solution is diluted with a solvent,
The reason for setting the concentration to 10 to 100 ppm is that if the concentration is less than 10 ppm, the concentration is too thin to be effective as a hard coating solution (diluting solution), and if it exceeds 100 ppm, the concentration is too high and the hard coating agent on the substrate exceeds the required amount. Is applied, and as a result, a hard coat layer having good adhesion and a gradient is not formed.

In the present invention, a generally known photocurable resin is used as the main agent for the hard coat, and those having optical characteristics that are not inconvenient for recording and reproducing are preferable. For example, bisphenol A epoxy acrylate,
Examples thereof include fatty acid-modified epoxy acrylate, urethane acrylate, and polyfunctional oligoester acrylate. The same solvent is preferably used as the solvent for diluting the hard coat agent and the hard coat main agent, and any solvent may be used as long as it is compatible with the hard coat main agent and does not attack the transparent substrate 1. For example, toluene, toluene /
Butyl acetate mixed solvent, methanol, isopropyl alcohol and the like can be mentioned.

In the present invention, it is preferable that the transparent substrate has little inconvenience in optical recording / reproducing,
Moreover, it is sufficient if it has a high transmittance with respect to the light used. For example, glass, acrylic resin, polyester resin, polycarbonate resin, vinyl resin, polysulfone resin, polyimide resin, polyacetal resin, polyolefin resin, polyamide resin, cellulose derivative and the like can be used.

A wide range of recording layers can be used as long as information can be recorded by light energy. For example, organic dyes such as polymethine dyes such as cyanine, naphthoquinone dyes or phthalocyanine pigments can be used. Can be mentioned.

As the inorganic material, a metal, a semimetal, etc., such as a low melting point material such as Bi, Sn, Te or As,
Examples thereof include complex compounds in which Se, S, O, C and the like are bonded, Te-TeO ₂ system recordable by phase change, and silver halide recordable by change in optical density.

In the present invention, the adhesive layer used is one that does not react with the recording layer and does not deteriorate the function of the recording layer. For example, a hot-melt type ethylene-vinyl acetate copolymer and its modified resin, ethylene- Ethyl acrylate copolymer, vinyl acetate-acrylate copolymer,
Examples include polyimide resins and epoxy resins.

The back substrate may be made of any material such as glass, plastic and metal, but is preferably the same material as the transparent substrate.

The hard coat layer 2 of the card-shaped optical recording medium may be formed before or after the optical recording layer is formed.

[0023]

EXAMPLES The present invention will be described in more detail based on the following examples.

Example 1 A solution of a dye of the following general formula (I) dissolved in 2-butanone was spinner coated on the pregroove side of a 0.4 mm-thick polycarbonate substrate with pregrooves to a thickness of about 900.
A recording layer of A was formed.

[0025]

[Chemical 1] A 0.3 mm-thick polycarbonate backing substrate was bonded thereto via an adhesive (ethylene-vinyl acetate copolymer).

Next, the ultraviolet curable resin Unidick 17-
A hard coating agent of 824-9 (manufactured by Dainippon Ink and Chemicals, Inc.) and toluene (weight ratio 1: 1) was further diluted with toluene to 10 ppm, and the opposite side of the pregroove of the polycarbonate substrate was washed by a spin method. . Further, the above hard coating agent was applied thereon by a spin coating method, and then the lamp power was 80 W / cm and the sample-lamp distance was 1
A card-like optical recording medium was obtained by photo-curing at 6 cm to provide a hard coat layer having a thickness of 4 μm.

The pencil hardness of the surface of the hard coat layer was F, and sufficient hardness was obtained. Further, the pencil hardness near the middle of the hard coat layer was H and that near the polycarbonate substrate / hard coat layer interface was HB, confirming the hardness gradient in the thickness direction of the hard coat layer. Adhesion to the substrate was good, and cracks did not occur in the bending test because of the above-mentioned gradient.

[0028]

[Other Examples]

Example 2 A 0.3 mm-thick polycarbonate substrate with pregrooves was washed on the opposite side to the pregroove side with the hard coating agent diluent used in Example 1 by a spin method. The substrate was placed in a constant temperature bath at 60 ° C. filled with toluene vapor in a state where a small amount of the diluted solution remained, and heat-treated for 1 minute. On top of that, Example 1
After applying the hard coating agent used in 1. by the spin coating method, the lamp power was 80 W / cm, the sample-lamp distance was 16
The film was photocured at a thickness of cm to form a hard coat layer having a thickness of 3 μm.

The pregroove side of this polycarbonate film substrate was spinner coated with a dye represented by the general formula (I) in the same manner as in Example 1 to form a recording layer having a film thickness of 1100 A, and an adhesive (ethylene- Vinyl acetate copolymer)
A polycarbonate back substrate having a thickness of 0.3 mm was bonded via the above to manufacture a card-shaped optical recording medium.

The pencil hardness of the surface of the hard coat layer was F, and a sufficient hardness as a hard coat was obtained. Also,
The pencil hardness near the middle of the hard coat layer was H, and that near the polycarbonate substrate / hard coat layer interface was B, confirming the hardness gradient in the thickness direction of the hard coat layer. The adhesion of the hard coat layer to the substrate was good, and no crack was generated even in the bending test.

[0031]

As described above, in the optical card manufactured by the method for manufacturing a card-shaped optical recording medium of the present invention, since the hardness of the hard coat layer in the thickness direction becomes a gradient, the occurrence of cracks can be prevented. Further, it has good adhesion to the substrate, high flexibility, and the surface hardness of the hard coat layer is equal to or higher than that obtained by the conventional method.

[Brief description of drawings]

FIG. 1 is a typical example of an optical card obtained by a manufacturing method of the present invention.

FIG. 2 is a process chart showing an example of a manufacturing method of the present invention.

FIG. 3 is a process chart showing an example of a manufacturing method of the present invention.

[Explanation of symbols]

 1 Transparent Substrate 1a Pre-groove Part 2 Hard Coat Layer 4 Recording Layer 5 Back Substrate 6 Adhesive Layer 7 Hard Coat Agent Diluting Solution 8 Hard Coat Agent 9 Light 10 Solvent Vapor 11 Constant Temperature Bath

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Claims (2)

[Claims] 1. A method of manufacturing a card-shaped optical recording medium, comprising a transparent substrate, a recording layer formed on the groove surface, and a protective layer provided on the recording layer, the transparent substrate being provided on the opposite side of the groove surface.
A hard coat solution consisting of a transparent photo-curable hard coat main agent and a solvent is diluted with the same solvent to 10 to 100 ppm and washed with a dilute solution, and the hard coat agent is applied with a slight amount of the diluted solution remaining on the washed surface. And then photocuring to form a hard coat layer, which is a method for producing a card-shaped optical recording medium. 2. A method of manufacturing a card-shaped optical recording medium, comprising a recording layer formed on the groove surface of a transparent substrate, and a protective layer provided on the recording layer, wherein transparent photocuring is performed on the opposite side of the groove surface of the transparent substrate. The hard coat liquid consisting of the main agent of the mold and the solvent is washed with the same solvent at a dilution of 10 to 100 ppm, and a small amount of the diluted liquid remains on the washed surface under the atmosphere of solvent vapor at 60 ° C. A method for producing a card-shaped optical recording medium, which comprises heat-treating at 80 ° C. for a predetermined time, applying a hard coat agent, and then photocuring the hard coat layer to form a hard coat layer.