JPH03108139A - Continuous production of substrate for optical recording medium - Google Patents

Abstract

PURPOSE:To make continuous operation and to improve productivity by subjecting a sheet substrate to a corona discharge treatment and irradiating a UV curing resin liquid packed between the substrate and a rolled stamper with UV rays, thereby curing the resin. CONSTITUTION:A resin tank 9 contg. the liquid UV curing resin 8 which is cured by irradiation with UV rays is provided below the rolled stamper 6. The resin 8 is applied at a uniform thickness on the surface of the stamper 6 by a coating roller 10. The sheet substrate 1 is subjected to the corona discharge treatment by a corona discharger 3. This substrate 1 and the stamper 6 are brought into tight contact with each other and the resin 8 of the substrate 1 is irradiated with the UV rays from a UV lamp 12 through the substrate 1 and is cured. The resin 8 and the substrate 1 are peeled from the stamper 6 upon curing of the resin 8. The productivity is improved by continuously carrying out the operation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for continuously manufacturing an optical recording medium substrate suitable for optical writing and recording using a laser or the like.

C. Prior Art Conventionally, in optical information recording media such as optical disks or optical carts, optically detectable minute pits of several pits are formed in a track shape on a thin recording layer provided on a substrate. This allows high-density recording of information. In such optical information recording media, it is necessary to scan a laser beam along a track when recording and reproducing information, and therefore a substrate with a guide groove for tracking is generally used.

A method for manufacturing such guide grooves or substrates with guide grooves is compression molding, in which a softened plastic material is pressed with a stamper and then solidified.
on Igold) method, injection molding method in which molten plastic material is injected into a mold with a stamper and solidified, and guide grooves are transferred from the stamper using ultraviolet curing resin (Photo Polymer). 2 P (Photo Polym
22 method is the best in terms of transferability of the guide groove, solvent resistance of the substrate, and ability to reduce optical distortion of the substrate.

The fact that the substrate has excellent solvent resistance is particularly advantageous when an organic material is used as the recording material and a recording layer is formed by coating. In this case, it is possible to use solvents that cannot be used with general plastic substrates such as acrylic and polycarbonate because they would corrode the substrate, which greatly expands the range of recording materials that can be used. Become. Furthermore, the 2P method has the great advantage of requiring very little capital investment compared to other methods.

However, the 22 method has a problem in that it takes longer to manufacture per substrate than other methods, making it unsuitable for mass production. Therefore, WO38103311 (patent application 1986-
No. 506,504), by using an rX disk on which a concavo-convex pattern is formed and transferring the concavo-convex pattern of this master onto a film base material, a film-like optical information recording medium substrate can be obtained. Continuous manufacturing techniques have been proposed. Specifically, after applying an ultraviolet curing resin to a roll-shaped stamper on which a concavo-convex pattern is formed,
A technique has been proposed in which the film substrate is overlapped with a film substrate, the ultraviolet curable resin is cured by irradiation with ultraviolet rays, and then the film substrate and the cured ultraviolet curable resin are peeled off using a stamper.

[Problems to be Solved by the Invention] On the other hand, the requirements for the ultraviolet curable resin used in the 22 method include good adhesion to the substrate, good releasability from the stamper, and a recording layer. Resins that have excellent curability and do not deteriorate the recording layer tend to have relatively poor adhesion to the substrate. Therefore, a method is being used to improve the adhesion of the resin using a brimer. From the viewpoint of productivity, a UV-curable type of brimer is suitable, but it increases the number of steps such as applying the brimer and curing by UV irradiation, and the increase in the number of steps reduces the yield. However, there were problems such as deterioration of the recording layer.

Furthermore, general-purpose polyolefin substrates such as polymethylpentene, which have excellent birefringence and cost efficiency, have the problem of repelling ultraviolet curable resin and poor adhesion with ultraviolet curable resin due to the low surface energy of the substrate. had.

The present invention has been made in view of the above-mentioned problems, and provides a substrate for optical recording media in which the adhesion between the substrate and the ultraviolet curing resin is improved by subjecting the sheet substrate to a corona discharge treatment, using a brimer. The purpose of this invention is to provide a continuous manufacturing method that reduces the number of steps, increases productivity, and improves yield compared to conventional methods.

Furthermore, the present invention uses a general-purpose polyolefin substrate which is advantageous in terms of birefringence and cost, and continuously manufactures a substrate for an optical recording medium with good adhesion between the substrate and an ultraviolet curing resin with high productivity. The purpose is to provide a method.

[Means for Solving the Problems] That is, the present invention uses a rolled stamper having a fine uneven pattern corresponding to guide grooves and/or information,
A method for continuously manufacturing a substrate for an optical recording medium by transferring and forming a concavo-convex pattern of the stamper onto a substrate using an ultraviolet curable resin, a step of subjecting a sheet substrate to a corona discharge treatment, a step of treating a sheet substrate with a corona discharge; , after being brought into close contact with a rolled stamper coated with ultraviolet curing resin,
A substrate for an optical recording medium, characterized in that the steps of curing the resin on the sheet substrate by irradiating ultraviolet rays through the sheet substrate, and peeling off the cured resin and the sheet substrate from a roll stamper are performed as a series of steps. This is a continuous manufacturing method.

Hereinafter, the undeveloped Ill will be explained in detail with reference to the drawings.

FIG. 1 is an explanatory diagram showing an example of a method for continuously manufacturing a substrate for an optical recording medium. In FIG. 1, a light-transmitting sheet substrate 1 is configured to be fed out by a feeding roller 2. As shown in FIG. The sheet substrate l is not limited in any way as long as it is flexible, such as polycarbonate.

Plastic sheets such as acrylic resin, polyolefin resin, polyester resin, and epoxy resin can be suitably used.

3 indicates a corona discharger, 4 is an electrode, and 5 is a ground. Between electrode 4 and earth 5 there is usually a frequency of 20 to 30 KI.
+7. An alternating current electric field with a voltage of about 10 to 30 KV is applied to cause corona discharge. The shape of the electrode 4 is a wire electrode, a roller electrode made of a wire covered with ceramics, and a pin electrode made of a large number of bottles lined up.

Any ball electrode etc. can be used, but sheet substrate l
In order to process the sheet substrate evenly in the width direction, it is desirable to use a wire electrode.More preferably, a split electrode consisting of wires arranged in parallel for both the electrode 4 and the ground 5 is preferable.This corona discharge treatment allows the surface of the sheet substrate to be Breaking of molecular bonds and oxidation by ozone occur, improving the paintability and adhesion of the UV-curable resin.

Reference numeral 6 denotes a roll-shaped stamper, and a guide groove and irregularities corresponding to information are formed on the surface of the stamper. The sheet substrate l sent out from the feeding roller 2 and subjected to corona discharge treatment by the corona discharger 3 is conveyed along the circumference of the rolled stamper 6.

The diameter of the rolled stamper 6 varies depending on the thickness and material of the sheet substrate l, but for example, considering a 1.2 mm thick polycarbonate optical disk, it is preferably φ 300 or more. Taking this into consideration, φ150 votes or more is preferable.

Such a rolled stamper 6 has a thickness of 0.1 to 0.3 m.
A method of gluing a flat stamper of m along the roll surface with an adhesive, or a method of mechanically fixing it with screws, etc.
Alternatively, it can be produced by directly stamping on the roll surface.

The nip roller 7 transfers the sheet substrate l to the rolled stamper 6
It has a force that presses against the surface of the surface. A resin tank 9 containing a liquid ultraviolet curing resin 8 that is cured by ultraviolet irradiation is provided below the rolled stamper 3. In this resin tank 9, liquid ultraviolet curable resin 8 is applied to the surface of the roll-shaped stamper 6 by an application roller 10 that rotates while being pressed against the surface of the roll-shaped stamper 6. After adjusting the thickness of the resin liquid applied in this way to be uniform with the plate 11, the resin liquid applied in this manner is transferred to the sheet substrate by the nip roller 7.
and the rolled stamper 6. The thickness of the coating is adjusted between 0.11 is and 50 #Lm so as to reduce the inclusion of bubbles.

As the ultraviolet curable resin 8, a prepolymer, oligomer, monomer, etc. having an unsaturated bond in the molecule can be used. For example, one or more types of unsaturated polyesters, acrylates such as epoxy acrylate, urethane acrylate, and polyether acrylate, and methacrylates such as epoxy methacrylate, urethane methacrylate, polyether methacrylate, and polyester methacrylate are combined in one molecule with unsaturated A photopolymerizable heptamer having a bond, such as a mixture of functional heptamers such as dicyclopentenyl acrylate, 1,3-butanediol acrylate, polyethylene glycol diacrylate, and pentaerythritol triacrylate, and further as a polymerization initiator. Radical-generating compounds such as helogenated acetophenones, benzophenone, benzoin, benzoin ether, Michler's ketone, benzyl, benzyl dimethyl ketal, tetramethylthiuram monosulfide, and thioxanthone are used, and they are easy to peel off from the stamper in the hardened state and recordable. The liquid UV curing resin 8 may be applied to the rolled stamper 6 as long as it matches well with the layer, and the application of the liquid ultraviolet curable resin 8 to the rolled stamper 6 is not particularly limited. The coating method can be selected depending on the viscosity and coating film thickness from among the known coating methods used in the above. Alternatively, the ultraviolet curing resin 8 may be applied directly to the sheet substrate using a coating roll 10'.

The sheet substrate 1 that has passed through the nip roller 7 is coated with an ultraviolet curable resin liquid filled between the sheet substrate 1 and the rolled stamper 6 over the entire width thereof by an ultraviolet ray tube 12 provided above the rolled stamper 6. The ultraviolet curing resin 8 is cured by irradiating ultraviolet light. The delivery roller 13 has a function of peeling off the sheet substrate 1 and the layer of the ultraviolet curing resin 8 that has been cured while being fixed thereto from the rolled stamper 6.

In this way, a concavo-convex pattern corresponding to the information on the optical disc is transferred onto the substrate, and substrates for optical information recording media can be continuously manufactured. Note that, if necessary, a step of further irradiating ultraviolet rays after peeling off the ultraviolet curable resin 8 may be provided.

In addition, the feeding speed of the sheet substrate l is 0.05 to 5 m/s.
In, preferably in the range of 0.05 to 2.5 s/sin. If the speed is less than 0.05 s/sin, productivity cannot be increased, and if the speed exceeds 5 m/in, air bubbles may be mixed in. It becomes easier.

[Example] Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 After forming a photoresist (trade name, AX-1300 manufactured by Hoechst) V with a film thickness of 10 on a glass master,
After exposure using a laser cutting device and then development to form a concavo-convex pattern, a Ni thin film was formed on the formed concavo-convex pattern by sputtering to make the surface conductive, and then electroforming was performed to form a concavo-convex pattern. , 1 part N
The N15i for 3 and 5 inches with a groove width of 0.6 IL, a width of 1.6 mm, a groove depth of 900 mm, and a spiral-shaped uneven pattern was then peeled off from the glass master disk. ! I got the 'l' plate stamper.

Using an epoxy adhesive (trade name: EP-170, manufactured by Cemedine), the obtained Ni plate stamper was stamped with an outer diameter of 4.
Twelve stampers were adhered in a row to the side of a roller with a width of 150 mm and a width of 150 to produce a rolled stamper.

A polycarbonate sheet substrate with a thickness of 1.2mm and @JI20m was used as the substrate, and the sheet substrate was moved at a speed of 2.4cm/
■ In, this sheet substrate is supplied with a slit interval of 10 ■
Wire electrodes with a length of 110 layers were arranged in the width direction of the sheet, and corona discharge treatment was performed at a frequency of 25, 11z, and a voltage of 22 KV. (nv os-z generator,
Tantic (Denmark) m) The surface tension of the sheet substrate at this time had increased from 35 dyne/cm to 72 dyne/cm or more.

An ultraviolet curable resin having the composition shown in Table 1 below was applied to the uneven surface of the rolled stamper to a thickness of 25% IA, and the rolled stamper and sheet substrate were brought into close contact with each other using a nip roller, and then spread out. Ultraviolet light (4Kw high pressure mercury lamp, 300■W) is applied to the ultraviolet curing resin over the entire width of the board.
/cm”) to cure the ultraviolet curable resin.

Next, the sheet substrate and the cured ultraviolet curable resin on it were peeled off using a roll stamper to obtain a sheet substrate having an uneven pattern with a width of 0.6μ, a pitch of 1.6pm, and a groove depth of 900. . No defects such as air bubbles were observed in the sheet substrate obtained in this way, and the adhesion between the sheet substrate and the ultraviolet curing resin was also good, and when a cross-cut tape peeling test was performed, the resin did not peel off. It didn't happen.

Table 1 Composition of ultraviolet curable resin Urethane acrylate 30 parts Neopentyl glycol modified trimethylolpropane diacrylate 67 parts! -Hydroxycyclohexylphenylketone 3 parts Comparative Example 1 A sheet substrate having an uneven pattern was obtained in the same manner as in Example 1 except for the step of subjecting the sheet substrate to corona discharge.

50% of the ultraviolet curable resin cured on the sheet substrate was peeled off in a Gobanro tape peeling test.

Example 2 In a similar manner to Example 1, grooves @31. Pitch 12 end■,
A Ni flat plate stamper for optical cards having a striped concavo-convex pattern with a groove depth of 3000 mm was manufactured.

A rolled stamper was produced by adhering 10 stampers in rows to the side surface of a roller with an outer diameter of 200 mm and a diameter of 130 holes.

A polymethyl pentane sheet substrate with a thickness of 0.4 mm and 9% 1120 mm was used for the substrate, and the sheet substrate was heated at a speed of 31/1.
corona discharge treatment was performed in the same manner as in Example 1. At this time, the surface tension of the sheet substrate is Z5dyne/a
m to 52 dyne/am. Further, on the uneven surface of the roll-shaped stamper, an ultraviolet curable resin having the composition shown in Table 2 was applied to a thickness of 20 μm, and the same operation as in Example 1 was carried out, so that the groove width was 3 and the pitch was 12 μm. A sheet substrate having a concavo-convex pattern with a groove depth of 3000 was obtained.

The substrate obtained in this way had no defects due to air bubbles, and the adhesion between the sheet substrate and the ultraviolet curing resin was also good, and when a cross-cut tape peeling test was performed, no peeling of the resin occurred. .

Table 2 Composition of ultraviolet curable resin Epoxy acrylate 19 parts Neopentyl glycol-modified trimethylolpropane diacrylate 64 parts Dipentaerythritol hexaacrylate 14 parts ■-Hydroxycyclohexyl phenyl ketone 3 parts Comparative Example 2 The process of corona discharge treatment on the G-T's board Except for this, the other steps were the same as in Example 2 to obtain a sheet substrate having a concavo-convex pattern. However, there was some residual transfer of the ultraviolet curable resin onto the rolled stamper, making it necessary to replace and clean the rolled stamper. Further, the ultraviolet curable resin cured and transferred onto the sheet substrate was also peeled off by Govan 1] tape peeling test.

[Effects of the Invention] As explained below, according to the present invention, the following effects can be obtained.

(1) Continuous manufacturing can improve productivity.

(2) Compared to the case where a brimer is used, the number of steps can be reduced, productivity is high, and the adhesiveness between the substrate and the ultraviolet curing resin can be improved to improve the yield.

(3) It is also possible to use a general-purpose polyolefin substrate which is advantageous in terms of birefringence and cost.

[Brief explanation of drawings]

FIG. m1 is an explanatory diagram showing an example of a method for continuously manufacturing a substrate for an optical recording medium. l... Sheet substrate 2... Feeding roller 3.
... Corona discharger 4 ... Electrode 5 ... Earth
6... Rolled stamper 7... Nip roller 8... Ultraviolet curing resin 9... Resin tank
10-... Application roller 11... Blade
12-... Ultraviolet lamp 13... Delivery roller

Claims (2)

[Claims] (1) A substrate for optical recording media by using a roll-shaped stamper having a fine uneven pattern corresponding to guide grooves and/or information and transferring the uneven pattern of the stamper onto the substrate using an ultraviolet curing resin. In the continuous manufacturing method, the sheet substrate is subjected to a corona discharge treatment, the treated sheet substrate is brought into close contact with a rolled stamper coated with an ultraviolet curing resin, and then ultraviolet rays are irradiated through the sheet substrate. 1. A method for continuously manufacturing a substrate for an optical recording medium, characterized in that a step of curing a resin on a sheet substrate and a step of peeling the cured resin and the sheet substrate from a roll stamper are performed as a series of steps. (2) Claim 1, wherein the sheet substrate is polymethylpentene.
A continuous manufacturing method for the optical recording medium substrate described above.