JP2617980B2 - Friction sheet for tape cassette - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction sheet for a tape cassette, which is disposed between a case containing a magnetic tape and the magnetic tape so as to smoothly run the tape.

Technical Background of the Invention and Problems Thereof Generally, in a tape cassette using a magnetic tape such as a compact cassette, a video cassette, and a digital audio tape (DAT), frictional resistance is generated between the magnetic tape and the inner peripheral surface of the cassette case. A friction sheet for reducing the magnetic tape to make the running of the magnetic tape smooth is provided. This friction sheet is made of a highly slippery sheet such as ultrahigh molecular weight polyethylene or polytetrafluoroethylene resin, but all have a problem that they have high electric resistance and are easily charged. If the electric resistance is large, the frictional resistance increases due to static electricity generated by friction with the magnetic tape, so that the magnetic tape is liable to be worn. Further, the abrasion increases the contact resistance and may significantly hinder the running of the tape. Further, when the friction sheet is charged, it is discharged only after the high voltage state is reached, so that there is a possibility that noise is induced in the magnetic recording / reproducing apparatus.

Therefore, conventionally, the above problem has been solved by mixing or applying a conductive filler such as graphite or carbon to ultrahigh molecular weight polyethylene, polytetrafluoroethylene resin or the like. However, since the conductive filler such as graphite and carbon has a different color or gray, there still remains a problem that the visibility of the black magnetic tape stored in the magnetic tape cassette is poor. Here, the visibility means how easily the remaining amount of the magnetic tape can be visually confirmed.

In addition, in order to solve such disadvantages of the related art, it is conceivable to include a conductive material for preventing static electricity and a pigment for improving visibility together in a single plastic film. The present inventors have confirmed that the vividness of the color has a disadvantage that it becomes turbid due to the inclusion of the conductive material, which is not practical.

Object of the Invention The present invention has been made in view of such circumstances,
The purpose is to increase the visibility of the magnetic tape in the tape cassette without significantly impairing the sliding characteristics and electrical resistance characteristics of the conventional friction sheet, and to obtain a fashionable friction sheet for a tape cassette. .

SUMMARY OF THE INVENTION In order to achieve the above object, the friction sheet for a tape cassette according to the present invention includes a colored plastic film colored with a pigment and a white plastic film mixed with a white conductive oxide. It is characterized by becoming.

According to such a friction sheet for a tape cassette according to the present invention, the friction sheet is composed of two layers of a colored plastic film and a white plastic film, and the colored plastic film has good sliding characteristics and visibility. The inconvenience of the prior art is eliminated at a glance by giving the white plastic film good antistatic properties. Particularly, in the present invention, since a white conductive plastic film is laminated on the back surface of the colored plastic film,
The vividness of the color tone of the colored plastic film is maintained, the visibility of the tape is remarkably improved, and the fashionability is also excellent.

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

1 is a sectional view of a friction sheet for a tape cassette according to an embodiment of the present invention, FIG. 2 is a plan view of the tape cassette, FIG. 3 is a plan view of the tape cassette when the upper tape cassette is removed, FIG. 4 is a sectional view of a friction sheet for a tape cassette according to another embodiment of the present invention.

As shown in FIG. 1, a friction sheet 10 for a tape cassette according to the present invention
And a white plastic film 2 laminated on this surface. The overall shape of the friction sheet 10 is, for example, as shown in FIG.

The colored plastic film 1 is a portion that comes into sliding contact with the side end of the magnetic tape 3, and as shown in FIG. 2, the black plastic film wound around the reel 4 from the viewing window 6 formed in the tape cassette 5. Is colored so that the rest of the magnetic tape 3 can be easily seen.

Since the colored plastic film 1 is a portion where the side end of the magnetic tape 3 slides as described above,
It is preferable to be made of a material having excellent sliding characteristics. The material of the colored plastic film 1 that satisfies these characteristics is particularly preferably ultra-high molecular weight polyethylene, but examples include polytetrafluoroethylene (PTFE), polystyrene, polyester, and other plastics. As the ultra-high molecular weight polyethylene, HIZEX Million (manufactured by Mitsui Petrochemical Co., Ltd.), Hostalen (manufactured by Hoechst) and the like can be preferably used.

Further, in order to color the colored plastic film 1 to an appropriate color for the purpose of improving visibility or fashionability,
The film 1 contains a pigment. Film 1
Any of organic and inorganic pigments may be used as the pigment. For example, titanium white (white), nickel titanium yellow (yellow), red brick (red), molybdenum orange (red), cadmium orange (red), ultramarine (ultra blue), azo pigments, phthalocyanine pigments, tetrachloroisoindolinone yellow And quinacridone red to purple, dioxazine purple or a conductive compound based on polyolefin or PUC. The particle size of such a pigment is preferably 0.5 to 5 μm. The mixing ratio of such a pigment is preferably about 1 to 25% by weight with respect to the base colored plastic film. Furthermore, the layer thickness of the colored plastic film 1 in which such a pigment is blended is preferably 0.01 to 0.05 mm.

On the other hand, the white plastic film 2 needs to have conductivity in order to prevent the electrification of the friction sheet 10, and to maintain the color tone of the colored plastic film 1 laminated on the surface vividly. It is necessary to have a system and color. For this reason, the white plastic film 2 contains a white conductive oxide. Examples of the white conductive oxide include conductive TiO ₂ powders exhibiting white to deep blue white. This is TiO ₂
(A conductive TiO ₂ containing antimony-doped tin dioxide). At the time of compounding, after kneading conductive TiO ₂ with plastic,
It is preferable to form a film to increase the volume conductivity. Further, it is also possible to form a conductive layer by dispersing conductive TiO ₂ in a paint and applying this to the film surface.

The compounding weight of such a white conductive oxide is preferably 3 to 30% by weight, and more preferably 5 to 25% by weight, based on the base plastic film. When the content is more than 30% by weight, the functional strength of the film is reduced.
This is because the adhesive strength with the adhesive also decreases. The particle diameter of such a white conductive oxide is preferably 0.5 to 1 μm. Also,
As a plastic serving as a base of the white plastic film 2 in which such a white conductive oxide is blended, the same plastic as a base of the colored plastic film 1 or other layer films of the plastic film 2 may be used. Preferably, it is 0.05 to 0.09 mm.

In the present invention, in order to laminate the colored plastic film 1 and the white plastic film 2 as described above, these films 1 and 2 are preferably bonded by thermocompression bonding. The bonding temperature (fusing temperature) needs to be higher than the melting point of the plastic that is the base of the films 1 and 2. For example, when ultra-high molecular weight polyethylene is used as a base for films 1 and 2, its melting point is 136.
Since the temperature is around ℃, thermocompression bonding may be performed at a temperature of about 140 ℃. This thermocompression bonding is efficient when performed between rolls. As a means for bonding and laminating the films 1 and 2, other than the above-mentioned thermocompression bonding, for example, a means such as bonding with a conductive adhesive may be employed.

The present invention relates to a friction sheet 10 shown in FIG.
However, the present invention is not limited thereto, and can be variously modified within the scope of the present invention.

For example, as shown in FIG. 4, a number of fine holes 7 penetrating the front and back surfaces are formed in the colored film 1a,
The friction sheet 10a may be configured so as to enhance the sliding characteristics with respect to the magnetic tape 3 and to enhance the conductivity to enhance the antistatic effect. The opening ratio of the fine holes 7 is preferably 10 to 30%. If the porosity is 30% or more, not only does the film strength decrease, but also the color (white) of the film 2 is seen through the surface of the film 1.

Effect of the Invention As described above, the friction sheet for a tape cassette according to the present invention is formed by laminating a colored plastic film colored with a pigment and a white plastic film mixed with a white conductive oxide. Therefore, the visibility of the magnetic tape in the tape cassette can be significantly improved without impairing the slip characteristics and electric resistance characteristics of the conventional friction sheet. Also,
By changing the pigment incorporated in the colored plastic film laminated on the white plastic film in various ways, the color of the friction sheet seen through the window for viewing the tape cassette can be changed vividly, so fashion Is also excellent.

EXAMPLES Hereinafter, the present invention will be described based on more specific examples, but the present invention is not limited thereto.

Example 5% by weight of an orange polyolefin-based conductive compound ("Rio Conduct" (registered trademark) manufactured by Toyo Ink Co., Ltd.) was added to ultrahigh molecular weight polyethylene powder having an average particle diameter of 3 μm.
After mixing as a pigment, the mixture is filled into a cylindrical mold, fired to form a block, and the block is cut to a thickness of 0.
A 04 mm orange film was obtained.

On the other hand, 25% by weight of white conductive titanium oxide is blended as a conductive filler in the same ultra-high molecular weight polyethylene powder,
After tempering, a white film having a thickness of 0.06 mm was obtained.

Next, the orange film and the white film are stacked in two layers, heated to 140 ° C. and passed between a pair of rolls at a speed of 2 m / min, and the two-layer film is heat-pressed, Friction sheet for tape cassette (0.1m thick
m).

The two layers of film are bonded together by fusion, and the volume resistivity per unit thickness is 3 × 10 ¹⁴ (Ω · cm) for a sheet (0.1 mm thick) containing only pigment. On the other hand, in the sheet (thickness 0.12 mm) of this embodiment,
It was 1.6 × 10 ¹⁰ (Ω · cm).

[Brief description of the drawings]

1 is a sectional view of a friction sheet for a tape cassette according to an embodiment of the present invention, FIG. 2 is a plan view of the tape cassette, FIG. 3 is a plan view of the tape cassette when the upper tape cassette is removed, FIG. 4 is a sectional view of a friction sheet for a tape cassette according to another embodiment of the present invention. 1,1a Colored plastic film 2 White plastic film 3 Magnetic tape 5, Tape cassette 10,10a Friction tape for tape cassette

Claims (5)

(57) [Claims] 1. A friction sheet for a tape cassette comprising a laminated plastic film colored with a pigment and a white plastic film containing a white conductive oxide. 2. The friction sheet for a tape cassette according to claim 1, wherein the colored plastic film and the white plastic film are laminated by thermocompression bonding. 3. A friction sheet for a tape cassette, wherein the white conductive oxide according to claim 1 is conductive titanium oxide. 4. A friction sheet for a tape cassette, wherein the white conductive oxide according to any one of claims 1 to 3 is blended in an amount of 3 to 30% by weight based on the white plastic film. 5. The friction sheet for a tape cassette according to claim 1, wherein a number of fine holes are formed in the colored plastic film.