JPH04330630A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To provide the process for producing the magnetic recording medium having decreased drop-outs. CONSTITUTION:An interior finishing material having <=1X10<8>(OMEGA/cm<2>) surface electric resistivity and the half-life of a charge voltage within 1 second is used as a ceiling, a wall surface 2 and a floor 3. Further, the above-mentioned floor is a copper wire embedment type. A baking-painted panel consisting of a steel sheet having >=2mm thickness as its base body is used as the finishing material for the above-mentioned wall surface. A cover 4 for a wiring and piping pit which is a part of the above-mentioned floor surface is made of a stainless steel without coating. The magnetic recording media are produced in a clean room 6 constituted in such a manner.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating apparatus for coating type magnetic recording media, and more particularly to a method for manufacturing magnetic recording media with less dropouts.

0002

[Prior Art] Coated magnetic recording media usually have a thickness of 4 to 7 mm.
A long film of polyethylene terephthalate or the like having a length of 5 μm and a width of 100 to 1000 mm is coated with a magnetic paint using a coating device to form a magnetic layer and, if necessary, a back coat layer, and then dried and wound up. Thereafter, the coated surface is smoothed using a calender device, and then cut into a predetermined product width using a slitter device, wound up, and placed in a tape cassette to form a product.

In recent years, with the increasing density of magnetic recording media,
Dropouts are a serious defect in product quality.
Among the causes of dropout, foreign matter on or in the magnetic layer is the most important factor.

Conventionally, therefore, it has been common practice to install a coating device, a calender device, and a slitter device (not shown) in a process clean room. The interior finishing materials for such a clean room include Keical painted boards for the ceiling and walls, PVC sheets for the floor, piping and wiring to connect to equipment are placed inside the pit, and painted iron plates are used as the pit cover material. It is commonly used.

[0005]

[Problems to be Solved by the Invention] However, in clean rooms using the above-mentioned interior materials, it has not always been possible to significantly reduce dropouts. Foreign matter generated by workers involved in the production of magnetic recording media in the clean room and equipment for producing the magnetic recording media floats inside the clean room and is released along with the air out of the clean room through an exhaust duct installed in the clean room. According to the studies conducted by the present inventors, not all foreign substances are exhausted, but some of them are removed from the ceiling, walls, etc. that make up the clean room.
Deposits adhere to the floor.

[0006] The reason for this is that the surface electrical resistivities of the Keical coated board and PVC sheet used as interior finishing materials for clean rooms are relatively high at 1010 (Ω/cm2) and 1013 (Ω/cm2), respectively. Foreign matter adheres to the material as it becomes electrically charged. Using the deposited foreign matter as a nucleus, other foreign matter adheres to it, and after it grows, it unsteadily scatters from the ceiling, walls, and floor, and attaches to the magnetic recording medium being manufactured, causing dropouts. It turned out that.

Furthermore, with conventional painted iron plates used for pit covers, the paint peels off due to the passage of workers, trolleys, etc., and then scatters in the clean room, which also causes dropouts.

An object of the present invention is to solve these conventional problems and provide a method and apparatus for manufacturing a magnetic recording medium with less dropout.

[0009]

[Means for Solving the Problems] In order to solve the above problems, the method for manufacturing a magnetic recording medium of the present invention uses an interior finishing material having a surface electrical resistivity of 1×10 8 (Ω/cm 2 ) or less for ceiling and wall surfaces. , is characterized by applying magnetic paint to the base film in a clean room used for the floor, the half-life of the charging voltage is within 1 second, using copper wire embedded flooring as the finishing material for the floor, and applying the magnetic paint to the base film in a clean room. thickness 2mm
The above-mentioned baking-painted panel made of a steel plate as a base is used, and the cover for the wiring and piping pit, which is a part of the floor surface, is made of unpainted stainless steel.

0010

[Function] With the above-described configuration, the amount of foreign matter adhering to the interior material of the clean room can be significantly reduced, so that the foreign matter will not be scattered again in the clean room, and the foreign matter will not adhere to the magnetic recording medium being manufactured. There is no.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be specifically described below with reference to the drawings. (FIG. 1) is a sectional view showing a clean room for carrying out the method of manufacturing a magnetic recording medium according to the present invention.

For the ceiling 1, walls 2, and floor 3, an interior finishing material is used that has a surface electrical resistivity of 1×10 8 (Ω/cm 2 ) or less and a charging voltage half-life of 1 second or less. This can significantly reduce the amount of charge on interior materials,
Foreign matter generated by a worker (not shown) or from the magnetic recording medium manufacturing device 7, which includes a coating device, a calender device, a slitter device, etc., does not adhere to and accumulate on the clean room interior material, and almost all of it is discharged through the exhaust port 8. It is forcibly exhausted together with air to the outside of the clean room by an exhaust fan 9. The exhausted air containing foreign matter is filtered by a filter (not shown), and after removing foreign matter,
It is again supplied into the clean room 6.

Furthermore, the floor 3 has a copper wire embedded structure,
Furthermore, by providing a ground (not shown), the amount of charge on the floor can be significantly reduced. Moreover, as a finishing material for the wall surface, specifically, a baked painted panel whose base material is a steel plate with a thickness of 2 mm or more is used. If the thickness is less than 2 mm, it is difficult to make the charging voltage half-life within 1 second.

Furthermore, a pit cover 4 for a pit 5 in which piping and wiring for connection to a magnetic recording medium manufacturing apparatus is placed.
By making the pit cover unpainted stainless steel, there is no dust generated from the pit cover, further enhancing the effectiveness of the invention.

In the clean room configured as above, the magnetic coating liquid shown in Table 1 was applied onto a polyethylene phthalate film with a thickness of 10 μm using a coating device, and the surface of the coating was smoothed using a calender device. After that,
A hardening process was performed for a certain period of time using a hardening device, and the magnetic recording medium was cut into 1/2 inch width using a slitter device.

[0016]

[Table 1]

The prepared magnetic recording medium was placed in a tape cassette, and its dropout was measured. Table 2 shows the results of detecting a dropout of −10 dB or more for 10 μsec as a playback output.

[0018]

[Table 2]

As a comparative example, a magnetic recording medium was prepared in the same manner as in the above embodiment using a conventional coating apparatus, and the dropout was measured. The results are shown in Table 2.

[0020]

Effects of the Invention As described above, according to the method of manufacturing a magnetic recording medium according to the present invention, it is possible to significantly reduce the adhesion of foreign matter to the clean room interior material, thereby significantly reducing the dropout of the magnetic recording medium, and improving the quality of the product. It has become possible to significantly improve quality.

[Brief explanation of drawings]

FIG. 1 is a side view showing a method of manufacturing a magnetic recording medium according to an embodiment of the present invention.

[Explanation of symbols]

1 Ceiling 2 Wall surface 3. Floor 4 Pit cover 5 Pit 6 Clean room 7 Manufacturing equipment 8 Exhaust port 9 Exhaust fan

Claims (4)

[Claims] Claim 1: Surface electrical resistivity is 1×108 (Ω/
cm2 ) or less and whose half-life of electrostatic voltage is within 1 second in a clean room using an interior finishing material for the ceiling, walls, and floor. Method. 2. The method for manufacturing a magnetic recording medium according to claim 1, wherein a copper wire embedded type floor material is used for the floor. 3. The method of manufacturing a magnetic recording medium according to claim 1, wherein a baked painted panel whose base material is a steel plate with a thickness of 2 mm or more is used as the finishing material for the wall surface. 4. The method of manufacturing a magnetic recording medium according to claim 1, wherein the cover for the pit for wiring and piping, which is a part of the floor surface, is made of unpainted stainless steel.