JPS58105444A - Production of information carrier of high density - Google Patents

Abstract

PURPOSE:To simplify working and to shorten the time of reduction, by producing a signal and giving magnetism at one time to an information recording carrier which contains a resin-coated layer cured by ultraviolet-ray containing magnetic fine powder. CONSTITUTION:A desired amount of the ultraviolet-ray curing resin mixed with the magnetic fine powder is coated thin and evenly on the entire convex side of a base material 1a by a roll coating, a spin coating or other coating processes. A material 1 is put with a coated layer 1b turned up is put on the upper surface of a die 3 of a press, and the pressure is applied to the material 1 while moving up the die 3 by a hydraulic press. Thus contact between the layer 1b and a stamper 7 attached to a cope 5 of the press progresses while giving slight deformation of the material 1 gradually toward the outside. As a result, air is pushed outside to eliminate the existence of air bubbles between the layer 1b and the stamper 7. Under such conditions, the shutter 6 of an ultraviolet-ray source 10 provided at the lower part of the die 3 is opened to irradiate the ultraviolet rays to the layer 1b. Thus the formation and hardening are finished instantaneously. Then the hydraulic press 4 is opened to obtain an information recording carrier in which the information signal is transcribed and formed to the layer 1b containing the magnetic fine powder on the surface.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a high density information phase.

In Japanese Patent Application No. 55-48409, the present applicant proposed a method of recording signals by providing alternating magnetic portions and non-magnetic portions. As a method for manufacturing an information carrier based on such a signal recording method, a thermoplastic resin is used as the material of the information carrier, a concave-convex signal is formed on the thermoplastic resin by thermal recycling, and a concave-convex signal is formed on the concave-convex surface by vapor deposition or sputtering. The applicant has already proposed a method of providing a magnetic layer, or a method of filling the recess with a resin liquid mixed with magnetic powder and curing it. Because the thermoplastic resin that is the material for the information carrier is heated and melted to be molded, it has the drawback of requiring a large amount of heat and time.Additionally, a magnetic part must be placed on the surface after molding, making it a two-step process. It also has some drawbacks.

Recently, a manufacturing method using ultraviolet curable resin instead of thermoplastic resin has become known in order to shorten molding time5, but even this method requires two steps to form a magnetic layer after molding. The drawbacks of poor efficiency have not been improved.

The present invention has been made to solve the above-mentioned drawbacks of the prior art. ), in which an ultraviolet curable resin containing a desired amount of magnetic fine powder is applied to the surface of an umbrella-shaped base material that transmits ultraviolet rays, and this is used as the material of the magnetic information carrier; A stamper having a negative signal with respect to the final signal to be obtained is gradually pressed onto the ultraviolet curable resin coating layer containing the magnetic fine powder from the top of the umbrella shape to the periphery, and the stamper and the magnetic fine powder are bonded together. After the coating layer of the ultraviolet curable resin contained therein is completely adhered, ultraviolet rays are irradiated to form a signal.

Next, the present invention will be explained with reference to FIGS. 1 to 3, which are examples thereof.

In the present invention, a circular plate serving as the base material 1a of the information recording carrier is prepared in advance by molding, and an ultraviolet curable resin mixed with a desired amount of magnetic fine powder is applied to the convex surface of the circular plate to form the carrier material 1. A signal is formed on this coating layer 1b.

The material of the circular plate 1a, which is the base material 1a, has good adhesion to the ultraviolet curable resin mixed with a desired amount of magnetic fine powder, which will be described later. It is better to use plastic.

What is important when molding the base material 1a is that the opening 1a is not molded into a flat plate shape, but is shaped into an umbrella shape (in other words, the central part is the apex and the peripheral part is the base) It is formed to look like a part of a sphere.The base material 1a formed in this way is shown in FIG.

Note that the vertical and horizontal ratios have been changed here for clarity.

An ultraviolet curable resin mixed with a desired amount of magnetic fine powder is applied thinly and uniformly to the entire surface of the convex surface of the base material 1a prepared in this way by roll coating, spin cording, or the like. The ultraviolet curable resin mixed with the desired amount of magnetic fine powder is mainly composed of a prepolymer having a radically polymerizable Q unsaturated group and a monomer having an ethylenically unsaturated group, and contains a small amount of a polymerization initiator and an auxiliary agent. Magnetic fine powder, such as Fen Ni, is added to the ultraviolet curable resin.
C.

A desired amount of fine powders of metals such as, oxides thereof, alloys thereof, and alloy oxides thereof are mixed and dispersed in a well-balanced manner.

Such a material 1 is then fed out to a press machine.

As is clear from FIGS. 2 and 3, this press machine has a lower mold 6 and an upper mold 5. The lower mold 3 is made of a material that transmits ultraviolet rays, such as ultraviolet-transparent melas, and its upper surface is A tightening ring 2 is provided for fixing the periphery of the material 1, and the upper die 5 is provided with a stamper fastener 8 for attaching a stamper 7. Further, 10 is an ultraviolet light source located below the lower mold 5, 4 is a hydraulic press for the upper and lower parts of the upper mold 5, and 9 is a centering bush.

The material 1 described above is placed on the upper surface of the lower die 6 of the press machine as described above, with the coating layer 1b facing upward, and the tightening ring 2 is used to position the material 1 and fix its peripheral edge. At this time, since the upper surface of the lower mold 3 is formed in a flat shape, the material 1 contacts the lower mold 3 only at the peripheral edge, and the top of the material 1 does not come into contact with the lower mold 6 and must be slightly floating. This state is shown in FIG.

After that, when pressure is applied while raising the lower die in a hydraulic press, the contact between the coated layer 1b and the stamper 7 attached to the upper die 5 of the press machine occurs at the center, that is, the top of the coated layer 1b. At first there is a point contact, and then the contact progresses toward the outer periphery while slightly deforming the material 1. This pushes out air and prevents air bubbles from entering between the coated layer 1b and the stamper 7. At the same time, it goes without saying that the air between the material 1 and the upper surface of the lower die 3 will escape from the periphery as pressure is applied.In this state, pressure is applied to the specified pressure by the hydraulic press until the specified pressure is reached. At this point, the shutter 6 of the ultraviolet light source 10 installed at the bottom of the lower mold is opened to irradiate the coating layer 1b with ultraviolet rays, thereby completing molding curing instantly.

In this case, unlike the case of molding by recycling heating and cooling, curing of the resin is completed almost instantaneously, so it is possible to significantly shorten the time compared to the case of thermal recycling. When the curing by ultraviolet rays is completed and the hydraulic press 4 is opened, an information recording carrier is obtained in which information signals are transferred and molded 2 onto the ultraviolet curable resin coating layer 1b containing magnetic fine powder on the surface. Here, the material 1, which was initially umbrella-shaped, was deformed into a flat shape by pressure, and in addition, the pressure was released due to shrinkage that occurs when the ultraviolet curable resin containing magnetic fine powder is cured. However, the return of the deformation is very slight and the shape becomes almost flat.

With such a configuration, the information recording carrier can be manufactured quickly and with stable quality without air bubbles.

The feature of the present invention is that the base material 1a is formed in advance into an umbrella shape, and a thin coating layer 1b of an ultraviolet curable resin containing a desired amount of magnetic fine powder is applied on the convex surface of the base material 1a, and ultraviolet rays are applied under pressure. The signal is transferred and molded onto this coating layer -1b by irradiation. What is important here is that when pressurizing, it is possible to apply pressure while pushing out air, thus completely preventing air entrainment.

■ Although the material 1 has been formed into an umbrella shape, a coating layer 1b of an ultraviolet curable resin containing a desired amount of magnetic fine powder is applied to the convex surface of the material 1, and a signal is generated by applying ultraviolet rays while applying pressure to the material 1b. The coated layer 1b of the ultraviolet curable resin, which is transfer molded and contains a desired amount of magnetic fine powder, shrinks slightly when the signal molding is completed, so that it has an umbrella-shaped curvature in the direction of loosening.

In addition, the umbrella shape is deformed into a flat shape by application and pressure, and after the pressure is released, the umbrella shape becomes almost flat, and even if it does return, it will be to the extent that it does not interfere with reproduction. By the way, according to the inventors' experiments, the diameter is 120 + 1111
Base material 1 prepared in advance as an information recording carrier with a thickness of 0.5 m
If the difference in height between the center part and the outermost part of a (difference between the top and bottom of the umbrella shape) is 80μ, the difference in height after signal molding is 30μ.
It was reduced to μ, and it was at a level where there was no problem in signal reproduction.

Another feature of the present invention is that conventionally molding signals and imparting magnetism were performed in two steps, but in the present invention they can be performed simultaneously, simplifying work, shortening manufacturing time, and reducing energy consumption. It is possible to achieve this goal.

Furthermore, another feature is that an ultraviolet curable resin containing magnetic fine powder is applied to the base material 1a molded into an umbrella shape to a thickness necessary for molding, and this is used as the molding layer 1b, thereby reducing the amount of resin used. In addition, if the quality of the ultraviolet curable resin containing this magnetic fine powder is strictly controlled and coated, a high quality information recording carrier can be manufactured. A signal having a magnetic layer can be formed by using the magnetic layer. Here, the thinner the molding layer 1b is, the shorter the molding time can be. However, as a result of various experiments, in order to obtain a stable information recording carrier of good quality, the thickness of the molding layer 1b containing the magnetic fine powder is The depth must be at least 10 times the depth of the unevenness of the signal to be molded,
The content of magnetic fine powder mixed in the ultraviolet curable resin is 60
It was necessary to keep the amount below 1130% (good*L<1130% to 40%) and came to the conclusion that it was gold.

Magnetic fine powder is opaque to ultraviolet light, but since the ultraviolet curable resin layer is thin (・), when exposed to an ultraviolet light source,
The thickness of the molded layer 1b is 1.0 to 1.5 μm or more.

The particle size of the magnetic powder is closely related to the signal depth, and is suitably 115 or less of the signal depth. .

Therefore, when the signal depth is 1000 to 1500'%', the particle size of the magnetic powder contained in the ultraviolet curable resin is suitably 200 to soo% (o, o2 to 0.03 .mu.).

In addition, the thickness of the molded layer 1b and the thickness of the base material 1a overlap, so that warpage does not occur due to shrinkage during mold curing of the molded layer 1b made of ultraviolet curable resin (as shown in 1, the thickness of the base material 1a is the thickness of the molded layer 1a). It must be sufficiently thicker than 1b thickness.

In view of this point, the present inventors determined that the thickness of the base material 1a and the molded layer 1
As a result of various experiments on the relationship between the thickness of the base material 1a and the thickness of the molded layer 1b, the thickness of the base material 1a is required to be at least 50 times the thickness of the molded layer 1b, and preferably 10 times the thickness of the molded layer 1b.
It was concluded that a thickness of 0 times or more is appropriate. Therefore, in the case of a magnetic information recording carrier, the thickness of the base material 1a is preferably 0.05111 or more (preferably 0.1 or more), and 0.2 to 0.3 m.
The thickness is appropriate.

The thickness of the molded layer 1b in this case is 1 to 1.5 microns, but preferably 2 to 3 microns.

As described above, according to the manufacturing method 1 of the present invention, molding can be completed in 2 to 3 seconds instead of 20 to 30 seconds in the conventional technology, and the number of manufacturing steps is reduced. It is possible to manufacture a magnetic information recording carrier that improves work efficiency and is also of significantly superior quality with no adverse effects caused by the generation of bubbles.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is an explanatory diagram showing a base material that becomes an information recording carrier, (a) is a plan view thereof, and (b) is a diagram A-A of (a). 'Cross section at line,
FIG. 2 is an explanatory diagram showing the state in which the material of the information recording carrier is set in the press machine, and FIG. 3 is an explanatory diagram showing the state during molding. 1-Material 2-Tightening ring 3-Lower die 4-Hydraulic cylinder f-5-Upper die 6-Shutter 7-Stamper-
8-Stambar fastener 9-Centering bush 1
〇-Ultraviolet light source patent applicant Toppan Printing Co., Ltd. Figure 1 Figure 31 19

Claims (1)

[Claims] Substantially providing magnetic portions and non-magnetic portions alternatelyK
In the method of soaking a high-density information carrier on which signals are recorded, an ultraviolet curable resin containing a desired amount of magnetic fine powder is applied to the surface of an umbrella-shaped base material that transmits ultraviolet rays. This was used as the material for the high-density information carrier, and a stamper having a negative signal with respect to the signal to be finally obtained was gradually applied to the ultraviolet curable resin coating layer containing the magnetic fine powder from the top of the umbrella shape to the periphery. A method for producing a high-density information carrier, which comprises pressing the stand bar and the ultraviolet curable resin coating layer containing the magnetic fine powder into complete contact with each other, and then irradiating ultraviolet rays to form a signal.