JPH04286739A - Production of substrate for optical recording medium - Google Patents

Abstract

PURPOSE:To prevent the contamination of a stamper roll. CONSTITUTION:A cleaning roll 7 is brought into contact with the stamper roll 4 by which the stains of the stamper roll 4 are transferred to a cleaning roll 7 at the time of forming a preformat by using the stamper roll 4 on a sheet 8 extruded from a tee-die 2 of an extruder 1.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a method for manufacturing a substrate for an optical recording medium for optically recording and reproducing information, and more specifically, a method for manufacturing a substrate for an optical recording medium in which a stamper roll is provided with cleaning means. Regarding.

0002

[Prior Art] Conventionally, optical recording media use light for recording and reproducing.
For example, it is constructed by providing an optical recording layer on a transparent substrate through which a semiconductor laser or the like can pass, and further laminating this with a protective member. On this optical recording medium substrate (hereinafter abbreviated as substrate), a preformat with minute irregularities on the micron order, such as tracking grooves and address information pits, is formed in advance. Methods such as injection method, compression method, 2P method, and casting method are known as methods for creating a preformat. However, these methods have difficulty in satisfying mass production and cost efficiency. As a method to satisfy these requirements, for example, Japanese Patent Application Laid-Open No. 56-86721 discloses that a thermoplastic resin sheet is heated with an infrared lamp in a heating box, and then a pair of forming rolls is used to form a concavo-convex signal, thereby creating an information recording disc. A method of manufacturing is disclosed.

[0003] This method allows the roll sheet to be processed continuously using forming rolls, so it is very suitable for mass production, but it has the following problems. (1) Since the sheet is heated once it has been formed, the sheet will be deformed when it is heated and softened due to distortions during the sheet forming process, such as distortions caused by stretching, and even if a preformat pattern is transferred to it using a forming roll. A substrate with a highly accurate preformat cannot be obtained. (2) The heat-softened resin sheet is an elastic body, and fine unevenness preformat cannot be accurately transferred by pressing with forming rolls.

[0004] To solve these problems, Japanese Patent Publication No. 63-31847 discloses a method in which a base film is provided with an ultraviolet curable resin layer, a signal is transferred and cured using a stamper, and flexible disks are manufactured continuously. A method is disclosed. However, this method requires a large number of steps and is problematic in terms of cost reduction.

[0005] Therefore, the authors melted and extruded a thermoplastic resin to form a resin sheet, and used a stamper roll to transfer the uneven shape for a preformat signal onto the resin sheet to manufacture a substrate for an optical recording medium. I invented a way to do that.

However, even in this method, when the substrate is manufactured for a long period of time, resin, dust, etc. adhere to the surface of the stamper roll, and there is a problem that the uneven shape for the preformat signal cannot be accurately transferred.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of these conventional problems, and involves forming a resin sheet by melt-extruding a thermoplastic resin, and applying a stamper roll to the resin sheet. When manufacturing substrates for optical recording media such as optical disks and optical cards by transferring a concave-convex preformat shape, by providing a means to remove dirt adhering to the stamper roll, the concavities and convexities can be accurately printed even during long-term continuous production. The present invention was completed after learning that preformat signals can be transferred, and the purpose thereof is to provide a method for manufacturing an optical recording medium substrate that solves the above-mentioned problems.

[0008]

[Means for Solving the Problems] In order to achieve the above object, the present invention melts and extrudes a thermoplastic resin using an extruder equipped with a T-die to form a resin sheet, and at the same time, the extruded resin sheet has a predetermined shape. In the method of manufacturing a substrate for an optical recording medium in which a predetermined shape is transferred to the sheet by pressing a stamper roll having a shape, the surface of the stamper roll is cleaned by providing a cleaning means that comes into contact with the stamper roll. The cleaning means has a cleaning member along its outer peripheral surface and is a cleaning roll that rotates in contact with the stamper roll, and the cleaning member is made of ultrafine fibers.
This includes being an adhesive, and a thermoplastic resin to be extruded and provided with a means for keeping the temperature at a temperature higher than the surface temperature of the stamper roll and lower than its melting temperature.

According to the present invention, by providing a cleaning roll having a cleaning means, for example, a cleaning member along the outer circumferential surface, in contact with the stamper roll that transfers the uneven shape of the preformat, the dirt on the stamper roll can be removed. It is intended to be moved to a cleaning roll and disposed of.

[0010] As for this cleaning roll, it is important to remove dirt without damaging the stamper roll. Moreover, this stain is mainly caused by the extrusion resin evaporating and adhering to the roll.

On the other hand, the temperature of the stamper roll during molding is lower than the glass transition point (Tg) of the extruded resin, but the temperature is about 90 to 140° C. when extruding polycarbonate, for example.

[0012] For this reason, the cleaning roll must be able to withstand this temperature.

Therefore, specifically, (1) a method of mechanically removing dirt using a cleaning roll coated with a cleaning material such as ultrafine fiber, and (2) a method of removing dirt onto the cleaning roll side using a cleaning material such as an adhesive. (3) A cleaning roll coated with the same material as the resin to be extruded as a cleaning member is pressed onto the stamper roll at a temperature higher than the stamper roll temperature and lower than the melting point to cause dirt to adhere to the cleaning roll. .

[0014] The ultrafine fibers used in (1) are those that are more flexible than the stamper roll, thinner than the preformat pattern (3 to 0.8 μm), and heat resistant. For example, composite fibers of polyester and nylon, nonwoven fabrics, etc. may be mentioned.

[0015] As the adhesive for (2), there are silicone resins and various heat-resistant rubbers, and any adhesive that has good heat resistance can be used.

The present invention will be explained below based on the drawings. Figure 1 shows how uneven shapes such as guide grooves and preformat patterns are transferred to thermoplastic resin using a horizontal three-roll system.
1 is a schematic diagram showing a method of molding a substrate for an optical recording medium,
1 is an extruder, 2 is a T die, 3 is a first roll for molding,
4 is a stamper roll (second roll), 5 is a third roll, 6 is a take-up machine, and 7 is a cleaning roll.

The sheet 8 extruded from the T-die 2 of the extruder 1 is guided between a first roll 3 and a stamper roll (second roll) 4, where both rolls 3,
4, and the shape of a stamper (not shown) attached to the outer peripheral surface of the stamper roll 4 is transferred. The sheet 8 that has been transferred is then transferred to the third roll 5
After passing between the stamper roll 4 and the stamper roll 4, the stamper is taken up by a take-up machine 6.

On the other hand, a cleaning roll 7 is in contact with the stamper roll 4, and the stamper roll 4
The cleaning member 9 rotates substantially in synchronization with the rotation of the stamper roll, and dirt adhering to the surface of the stamper roll is constantly removed by a cleaning member 9 attached to the surface of the stamper roll.

[0019] As the thermoplastic resin used here,
Any material that can be used as a substrate for optical recording media may be used, such as polycarbonate, polystyrene, polysulfone,
Polyolefin etc. are used. The stamper roll is
Obtained by gluing or mechanically fixing a metal stamper to a mirror roll.

[0020]

[Examples] The present invention will be explained in more detail with reference to Examples below. Example 1 Using polycarbonate as thermoplastic resin, diameter φ6
The sheet was extruded using a 5 mm extruder (300 mm width T-die) to form a substrate. At this time, the temperature inside the extruder was 270°C, and the temperature of the T-die was 300°C. In addition, the first to third molding rolls are made of carbon steel with a chrome-plated surface and have a diameter of 300 mm.The stamper roll is a mirror-finish roll made of a nickel stamper (thickness 100 μm) made for optical cards. It was used by screwing it on. Further, the temperature of the roll was controlled by circulating oil through the roll. The temperature of the oil circulated through the first to third rolls is 80°C and 100°C, respectively.
℃, 130℃, take-up speed 3.0 m/min,
When extrusion molding was performed using a substrate with a thickness of 0.4 mm, the surface temperature of each roll was 110°C for the first roll and 110°C for the second roll.
The temperature was 120°C for the roll and 135°C for the third roll. Also, the cleaning roll used here has a diameter of φ100.
An ultrafine fiber (manufactured by Kanebo Co., Ltd., trade name: Zabina Mini Max) was wound around a 5 mm thick metal roll.

[0021] When substrates for optical recording media were manufactured continuously for a long time in this manner, no defects due to stains on the stamper roll were found on the substrates even after 15 hours. Example 2 A sticky synthetic rubber coated roller (HC-1 manufactured by Audio-Technica Corporation) was used as a cleaning roll. We also use a nickel stamper (thickness 150μm) with a spiral pattern for optical discs as a stamper roll.
A polycarbonate optical disk substrate (thickness: 1.2 mm) was obtained in the same manner as in Example 1, using a substrate affixed to a mirror-finished roll with an adhesive (SC55 manufactured by Sony Bond). At this time, the temperature of the oil for roll temperature adjustment was 90°C for the first roll, 110°C for the second roll, and 130°C for the third roll.
The take-up speed was 2 m/min.

[0022] In this way, 10 optical disk substrates are
After checking the stamper roll for a while, I found almost no dirt on the stamper roll. Example 3 A cleaning roll was prepared by coating the surface of a metal roll (diameter 150 mm) with polycarbonate to a thickness of 2 mm. The rest was the same as in Example 1, and the cleaning roll temperature was set to 140°C, which was higher than the stamper temperature of 110°C.

No stains were found on the stamper roll even after 20 hours of continuous molding. Comparative Example Molding was carried out under the same conditions as in Example 1 except for removing the cleaning roll. Polycarbonate powder began to adhere to the stamper roll approximately 30 minutes after the start of molding, and after approximately 1 hour, the substrate showed unevenness due to the contamination. has become clearly visible. In addition, a recording layer (organic dye; IRG-820 manufactured by Nippon Kayaku Co., Ltd.) was formed using this substrate to a thickness of 1000A, and a PC backing ( When an optical card was made by pasting the substrate with a substrate (thickness: 0.3 mm), its reflectance fluctuated finely between 16 and 22% due to irregular irregularities on the substrate, making it unusable.

[0024]

[Effects of the Invention] As explained above, by providing a cleaning means that comes into contact with the stamper roll to remove dirt, the stamper is constantly cleaned, and therefore extrusion molding can be performed continuously and efficiently. Can manufacture substrates. Furthermore, since the sheet is extruded and a preformat is formed, distortion of the substrate is eliminated and a highly accurate substrate can be manufactured.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view showing an example of a manufacturing apparatus used for implementing the present invention.

[Explanation of symbols]

1 Extruder 2 T-die 3 First roll 4 Second roll (stamper roll) 5
Third roll 6 Take-up machine 7 Cleaning roll 8 Sheet 9 Cleaning member

Claims (5)

[Claims] Claim 1: Melting and extruding a thermoplastic resin using an extruder equipped with a T-die to form a resin sheet,
A method for manufacturing a substrate for an optical recording medium, in which a predetermined shape is transferred to the extruded resin sheet by pressing a stamper roll having a predetermined shape to the extruded resin sheet,
A method for manufacturing a substrate for an optical recording medium, characterized in that a cleaning means is provided in contact with the stamper roll to perform extrusion transfer while cleaning the stamper roll surface. 2. Claim 1, wherein the cleaning means has a cleaning member along its outer peripheral surface and is a cleaning roll that rotates in contact with the stamper roll.
A method of manufacturing the described substrate. 3. The method for manufacturing a substrate according to claim 2, wherein the cleaning member is an ultrafine fiber. 4. The method of manufacturing a substrate according to claim 2, wherein the cleaning member is an adhesive. 5. The method of manufacturing a substrate according to claim 2, wherein the cleaning member is made of extrusion-molded thermoplastic resin, and means is provided to keep the temperature of the cleaning member at a temperature higher than the surface temperature of the stamper roll and lower than its melting temperature.