JPH10269743A - Magnetic recording tape cassette - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control deterioration of drop-out characteristic due to quality change of magnetic tape and improve rigidity of the tape by including the specific amount of cation-based antistatic agent to a resin rid for opening and closing an aperture at the part opposed to the magnetic tape extended in the magnetic recording tape cassette. SOLUTION: A front rid 103a and a back rid 103b are formed using, for example, ABS. As an antistatic agent, a cation-based surface activating agent is added in the amount of 1 to 100 ppm. In the magnetic recording tape cassette 100, the magnetic tape 120 is held between the front rid 103a of the rid 103 and the back rid 103b and is arranged at the position near both rids 103a and 103b. Adverse influence of anti-electrification agent can be prevented and deterioration of the drop-out characteristic can be controlled to the practical level by setting the amount of cation-based antistatic agent included in the rid 103 to 100 ppm or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic tape comprising a metal thin film type magnetic recording medium, and in particular, to a short wavelength magnetic recording signal (high density magnetic recording) such as a high band 8 mm video tape or a digital VTR. The present invention relates to a magnetic recording tape cassette suitable for recording and reproduction.

[0002]

2. Description of the Related Art Magnetic tapes having a ferromagnetic metal thin film in a magnetic layer have better characteristics than conventional coating type magnetic recording media in terms of recording density and the like, and are therefore used for video tape recorders. Has been put to practical use as a magnetic tape.

[0003] Also, considering the development of the magnetic tape field in the future, application fields such as digital video recorders and other higher-quality video recorders and digital tape recorders are expected to be widely used. I have.

FIGS. 1 and 2 show a perspective view and a schematic exploded view of a magnetic recording tape cassette, respectively. The magnetic recording tape cassette 100 includes an upper shell 101 and a lower shell 102, which accommodate a pair of reels 200 around which a magnetic tape 120 is wound. In addition, both shells 1
01 and 102, a pair of reels 20
An opening is provided in a portion facing the magnetic tape stretched over the opening 0, and the opening is opened and closed by a lid 103, in this example, a front lid 103a and a back lid 103b.

The reel 200 has an upper flange 201,
Lower tape 202 and magnetic tape 1 at the center between them
20 comprises a hub 203 in which it is wound.

In the magnetic recording tape cassette 100, a magnetic tape 120 is sandwiched between a front lid 103a and a back lid 103b of a lid 103 at a front portion thereof. Therefore, the magnetic tape 120 is disposed at a position close to both the lids 103a and 103b of the lid portion 103.

[0007] Plastic materials generally used for magnetic recording tape cassettes are poor conductors of electricity, and it is necessary to prevent electrification in order to prevent dust from being absorbed or making processing difficult. For this reason, it is necessary to use an antistatic agent.

As a method for preventing electrification of the magnetic recording tape cassette, a so-called external prevention method in which a surface active agent is applied to the surface, or a method in which a conductive material such as silver or copper powder or a surface active agent is mixed. Internal prevention laws and the like are known. Although the external prevention method is inferior in durability, it is a convenient method when it is desired to avoid changes in the physical properties of the material or to avoid difficulties in processing. The antistatic agent used in these methods for preventing electrification includes an anion-based antistatic agent, a cationic antistatic agent, and a nonionic antistatic agent.

[0009]

The lid 103 of the magnetic recording tape cassette 100 shown in FIG. 1 contains a cationic antistatic agent, for example, a cationic surfactant. In addition, there is an effect that charging of the magnetic tape 120 is prevented. Further, the lid 103 is made of a magnetic tape 120 from dust or the like.
Has the role of protecting

The above-mentioned cationic surfactant has a hydroxyl group (—O
Since H) is included, hydrophilicity increases when it is included. As the hydrophilicity increases, a resin lid portion 103,
It is known that the compatibility with the cationic surfactant is deteriorated and the cationic surfactant is leached on the surface, so that the antistatic effect is improved.

However, as the hydrophilicity increases, it becomes easier to adsorb moisture, which adversely affects the magnetic tape 120 stored in the magnetic recording tape cassette 100. That is, deterioration of magnetic properties and dropout deterioration due to the generation of rust occur.

This is because the magnetic tape 120
However, the cationic surfactant contained in the lid portion 103 adversely affects the properties of the magnetic tape 120 because it is located close to the lid portion 103.

In a home digital VTR or the like for recording digital image signals, the recording track pitch is extremely narrow, 10 μm, due to the necessity of high-density magnetic recording. The effects are more likely to appear than before, and thorough improvements are needed.

Therefore, the present inventor has conducted intensive studies and found that the amount of the cationic surfactant contained as an antistatic agent in the lid portion 103 of the magnetic recording tape cassette 100 is controlled to a specific range. As a result, it has been found that the deterioration of the dropout characteristic due to the deterioration of the magnetic tape can be suppressed to a practical level, the durability of the magnetic tape can be secured, and the smooth running property of the magnetic tape can be secured.

[0015]

A magnetic recording tape cassette according to the present invention has a pair of upper and lower shells, and a pair of tape reels around which a magnetic tape is wound are rotatably stored, and the magnetic tape is a pair of tapes. The magnetic recording tape cassette is stretched by a reel and has an opening in a portion facing the stretched magnetic tape, and the opening is made openable and closable by a rotating resin-made lid. It is assumed that the resin lid contains 1 to 100 ppm of the cationic antistatic agent.

According to the present invention, the amount of the cationic antistatic agent contained as an antistatic agent in the lid portion of the magnetic recording tape cassette having the resin lid portion is 100 p.
pm or less, the adverse effect of the cationic antistatic agent on the magnetic tape can be reduced, and as a result, the deterioration of the dropout characteristics due to the deterioration of the magnetic tape can be suppressed to a practical level, Durability can be ensured.

Further, by setting the amount of the cationic antistatic agent contained in the resin lid portion to 1 ppm or more, the charging of the magnetic tape can be prevented, and the stable running property of the magnetic tape can be secured. can do.

That is, when the lid portion of the magnetic recording tape cassette contains a large amount of a cationic antistatic agent, and the magnetic recording tape cassette is stored for a long time in a high-temperature and high-humidity environment, the cationic antistatic agent is removed from the lid portion. Volatilizes and adheres to the magnetic tape and reacts with the metal in the magnetic layer, or the hydrophilicity increases due to the cationic antistatic agent, which makes it easier to adsorb moisture, and is applied to the magnetic tape stored in the magnetic recording tape cassette. Deterioration occurs on the magnetic tape due to adverse effects, and the dropout characteristics deteriorate,
The durability also deteriorates. Therefore, the adverse effect of the cationic antistatic agent on the magnetic tape is reduced by controlling the cationic antistatic agent contained in the lid portion to 100 ppm or less.

On the other hand, as described above, since the cationic antistatic agent in the lid portion of the magnetic recording tape cassette has an antistatic effect on the magnetic tape, if the amount of the cationic antistatic agent is too small, In view of the fact that the antistatic effect of the magnetic tape cannot be sufficiently obtained and the running property of the magnetic tape may be hindered, by setting the amount of the cationic antistatic agent in the lid portion to 1 ppm or more, The running property of the magnetic tape can be ensured.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a magnetic recording tape cassette wherein the content of a cationic antistatic agent, for example, a cationic surfactant, contained as an antistatic agent in a lid portion is controlled to 1 to 100 ppm. A recording tape cassette is obtained.

Hereinafter, embodiments of the present invention will be described.
The magnetic recording tape cassette of the present invention can be applied to a magnetic recording tape cassette having the same structure as that shown in the perspective view and the exploded view in FIGS.

That is, as shown in FIGS. 1 and 2,
The magnetic recording tape cassette 100 includes an upper shell 10
1 and the lower shell 102 are united to accommodate a pair of reels 200 around which the magnetic tape 120 is wound. The magnetic tape 120 is spanned by a pair of reels 200, and has an opening at a front part of the shells 101 and 102 and at a portion facing the magnetic tape stretched over the reel 200. . This opening can be opened and closed by a lid 103 that is rotatably supported, in this example, a front lid 103a and a back lid 103b.

For the front lid 103a and the back lid 103b, for example, ABS (acrylonitrile styrene butylene) can be used, and a cationic surfactant is added to these lid portions as an antistatic agent. As the cationic surfactant, for example, C ₁₂ H
₂₅ N ⁺ (CH ₃ ) (C ₂ H ₄ OH) ₂ ClO ₄ can be used, but is not limited to this example.

The reel 200 has an upper flange 201,
Lower tape 202 and magnetic tape 1 at the center between them
20 comprises a hub 203 in which it is wound.

In the magnetic recording tape cassette 100, a magnetic tape 120 is sandwiched between a front lid 103a and a back lid 103b of a lid 103 at a front portion thereof. Therefore, the magnetic tape 120 is disposed at a position close to both the lids 103a and 103b of the lid portion 103.

In the resin-made lid portion 103 of the above-described magnetic recording tape cassette 100, a cationic surfactant is used as an antistatic agent in the production stage at 0.01 to 0.1.
4% by weight shall be added.

Here, the amount of the cationic surfactant contained in the resin-made lid portion 103 of the manufactured magnetic recording tape cassette 100 is measured, and the lid portion 103 having a different content of the cationic surfactant is measured. Are prepared as samples of [Examples 1 to 6] and [Comparative Examples 1 and 2], respectively.

The amount of the cationic surfactant contained in the resin lid 103 of the magnetic recording tape cassette 100 is measured by the following method.

First, each of the front lid 103a and the back lid 103b of the magnetic recording tape cassette 100 is pulverized, weighed at 5 g, and used as a powder sample. next,
100 ml of acetone is added to this powder sample, and extraction is performed for 2 hours. Thereafter, the supernatant is measured with a 50 ml measuring cylinder, and this is used as an extraction measurement sample solution. here,
If the extraction time is sufficient for extraction saturation,
It is not limited to two hours.

Next, the amount of the cationic surfactant in the lid portion of the sample liquid for extraction measurement is measured by gas chromatography-mass spectrometry (GC-MS analysis). In addition,
As the measuring device, for example, NEC DX-303 can be used.

The measurement was performed as described above [Examples 1 to
The amounts of the cationic surfactants of [6] and [Comparative Examples 1 and 2] are shown in the following (Table 1).

[0032]

[Table 1]

Next, the manufacturing conditions of the magnetic tape are shown in the following (Table 2). The manufacturing conditions of the magnetic tape are common to [Examples 1 to 6] and [Comparative Examples 1 and 2].

[0034]

[Table 2]

The structure of a vapor deposition device used for forming a magnetic layer of a magnetic tape will be described below. As shown in FIG.
In this vapor deposition apparatus, a feed roll 3 and a take-up roll 4 are provided in a vacuum chamber 1 evacuated from exhaust ports 15 and 16 to be in a vacuum state.
The non-magnetic support 2 runs sequentially on the take-up roll 4.

A cooling can 5 is provided between the feed roll 3 and the take-up roll 4 while the nonmagnetic support 2 is running. The cooling can 5 is provided with a cooling device (not shown) to suppress deformation and the like of the non-magnetic support 2 due to a rise in temperature.

The non-magnetic support 2 is sequentially sent out from the feed roll 3, passes through the peripheral surface of the cooling can 5, and is taken up by the take-up roll 4.
The guide rolls 6 and 7 allow the non-magnetic support 2 to run smoothly.

In the vacuum chamber 1, a crucible 8 is provided below the cooling can 5, and the crucible 8 is filled with a metallic magnetic material 9. On the other hand, an electron gun 10 for heating and evaporating the metallic magnetic material 9 filled in the crucible 8 is attached to the side wall of the vacuum chamber 1. In this electron gun 10, the electron beam B emitted from the
It is arranged at a position where it is irradiated to the metal magnetic material 9 inside. The metal magnetic material 9 evaporated by the irradiation of the electron beam B is deposited on the non-magnetic support 2 to form a magnetic layer.

A shutter 13 is provided between the cooling can 5 and the crucible 8 and in the vicinity of the cooling can 5 so as to cover a predetermined area of the non-magnetic support 2 running on the peripheral surface of the cooling can 5. The metal magnetic material 9 evaporated by the shutter 13 is deposited obliquely on the nonmagnetic support 2 within a predetermined angle range.

Further, at the time of depositing the magnetic layer, oxygen gas is supplied to the surface of the non-magnetic support 2 by an oxygen gas introducing pipe 14 provided through the side wall portion of the vacuum chamber 1 so that the magnetic properties, durability, and the like are improved. The weather resistance is improved.

The thickness of the magnetic layer of the magnetic tape is 200
The surface of this magnetic layer is coated with perfluoropolyether as a lubricant, and finally the magnetic tape 120 of the magnetic recording tape cassette 100 shown in FIGS. 1 and 2 can be obtained.

Examples 1 to 4 were prepared as described above.
For the magnetic recording tape cassettes of [6] and [Comparative Examples 1 and 2], the still characteristics and the dropout increase rate before and after storage were measured in a high-temperature and high-humidity environment. Here, the storage condition is 45 ° C,
The humidity was 80% for 4 days.

After storage under the above conditions, the still characteristics and dropout increase rate of the magnetic tape 120 near the lid 103 in the magnetic recording tape cassette 100 shown in FIGS. 1 and 2 were measured.

In the dropout, the reproduction output attenuation is -1.
A signal having a length of 0 dB or more and a signal missing length of 10 μsec or more is detected and counted for 5 minutes, a value per minute is obtained, and an increase rate (%) before and after storage in a high temperature and high humidity environment is obtained. It was taken.

The still characteristic is obtained from the recording signal in the initial state by:
The time (minutes) until 3 dB degradation was measured. In addition, the modified EVS-900 made by Sony was used for the measurement of the dropout and the measurement of the still characteristic.
The recording signal was performed using 50% white.

Further, the electrical resistance of the lid portion 103 and the state of jamming in the magnetic recording tape cassettes 100 of [Examples 1 to 6] and [Comparative Examples 1 and 2] were also measured.

Examples 1 to 6 and Comparative Examples 1 and 2
Table 3 shows the measurement results of the increase rate (%) of the dropout and the still characteristics.

[0048]

[Table 3]

In the above (Table 3), the cationic surfactant contained in the lid portion of the magnetic recording tape cassette of Examples 1 to 6 is 1 to 100 ppm. Under these conditions, the still characteristics of the magnetic tape before and after storage in a high-temperature and high-humidity environment were both 120 (minutes).
As described above, good values are shown, and it is understood that deterioration is extremely small.

The increase rate (%) of the dropout in [Examples 1 to 6] is suppressed to a relatively low value of 10 to 100 (%).

On the other hand, in Comparative Example 1, the cationic surfactant contained in the lid portion of the magnetic recording tape cassette exceeded 100 ppm. In this case, the still property was significantly reduced. It deteriorates and the rate of increase in dropout also becomes extremely high.

On the other hand, Table 3 shows that the more cationic surfactant contained in the lid portion of the magnetic recording tape cassette, the lower the electrical resistance (Ω).
This is because the cationic surfactant is effectively acting as an antistatic agent.

[Comparative Example 2] shows that the cationic surfactant contained in the lid portion of the magnetic recording tape cassette contained 1
ppm, but in this case, the lid 1 of the magnetic recording tape cassette 100 shown in FIGS.
03 was jammed by the magnetic tape 120, so-called jamming occurred, and it was impossible to measure the still characteristics and the rate of increase in dropout.

This is because a sufficient amount of the cationic surfactant contained in the lid portion 103 of the magnetic recording tape cassette 100 did not provide a sufficient antistatic effect.

As described above, when the cationic surfactant contained in the lid portion 103 of the magnetic recording tape cassette 100 exceeds 100 ppm, the magnetic recording tape cassette was stored for a long time in the high temperature and high humidity environment. rear,
It can be seen that the magnetic tape 120 near the lid 103 is deteriorated, the dropout characteristics of the magnetic tape are deteriorated, and the durability is also deteriorated.

If the cationic surfactant contained in the lid portion 103 of the magnetic recording tape cassette 100 is less than 1 ppm, the antistatic effect cannot be sufficiently obtained, and the running property of the magnetic tape is hindered. Come.

That is, in order to prevent electrification of the magnetic tape 120 and ensure stable running of the magnetic tape 120, the results of Table 3 show that the magnetic recording tape cassette 1
It can be seen that it is necessary to set the amount of the cationic surfactant contained in the lid portion 103 of No. 00 to 1 to 100 ppm.

In the above-described embodiment, the magnetic recording tape cassette having the front lid and the back lid made of resin has been described. However, the present invention is not limited to such a magnetic recording tape cassette. ,
The same can be applied to a magnetic recording tape cassette having only a resin front lid.

In the above example, the cationic antistatic agent contained in the lid portion is a cationic surfactant C ₁₂ H ₂₅ N ⁺ (CH ₃ ) (C ₂ H ₄ OH).
_{Although 2} ClO ₄ was used, the present invention is not limited to this example, and higher amine halogenates, alkylpyridinium halides, quaternary ammonium salts, cations S
Any type of commercially available cationic antistatic agent such as A, cation AB, and cation BB can be used, and is not particularly limited to the material and the trade name.

Means for forming the magnetic layer include a vacuum evaporation method in which a ferromagnetic metal material is heated and evaporated under vacuum to be deposited on a non-magnetic support, and an ionization method in which the ferromagnetic metal material is evaporated during discharge. A conventionally known method such as a plating method, a sputtering method in which atoms on a target surface are beaten by argon ions generated by causing a glow discharge in an atmosphere containing argon as a main component, and the like can be applied.

In the above-described embodiment, Co was used as the magnetic layer. However, the magnetic layer of the magnetic tape 120 of the magnetic recording tape cassette 100 of the present invention shown in FIG. 1 is not limited to this example. Not Fe, Ni
Ferromagnetic metals such as Co-Ni, Co-Fe-Ni, Fe
-Cu, Co-Cu, Co-Au, Co-Pt, Mn-
Al, Fe-Cr, Co-Cr, Ni-Cr, Fe-C
Ferromagnetic alloys such as o-Cr and Fe-Co-Cr-Ni are exemplified. These may be a single-layer film or a multilayer film. Further, an underlayer or an intermediate layer may be provided between the nonmagnetic support and the metal magnetic thin film, or in the case of a multilayer film, for improving the adhesion between the layers and controlling the coercive force. Further, for example, in order to improve the corrosion resistance near the surface of the magnetic layer, it may be an oxide.

Further, a protective film layer may be formed on the magnetic layer. This material may be any material that is generally used as a protective film for a normal metal magnetic thin film. For example, carbon, CrO
₂ , Al ₂ O ₃ , BN, Co oxide, MgO, Si
_{O 2, Si 3 O 4,} SiN X, SiC, SiN X -Si
O ₂ , ZrO ₂ , TiO ₂ , TiC and the like can be mentioned. These may be a single-layer film or a composite film.

As the non-magnetic support, any conventionally known non-magnetic support can be used. For example, polyesters such as polyethylene terephthalate, polyolefins such as polypropylene, cellulose triacetate, cellulose diacetate, cellulose derivatives such as cellulose acetate butyrate, polyvinyl chloride,
Vinyl-based resins such as polyvinylidene chloride, plastics such as polycarbonate, polyimide, and polyamide-imide;
Examples include metals such as aluminum and copper, light alloys such as aluminum alloys and titanium alloys, and ceramic single crystal silicon.

[0064]

According to the present invention, the amount of the cationic antistatic agent contained as an antistatic agent in the lid of a magnetic recording tape cassette having a resin lid can be reduced by 100%.
ppm or less, the adverse effect of the cationic antistatic agent on the magnetic tape can be reduced, and as a result, the deterioration of the dropout characteristics due to the deterioration of the magnetic tape can be suppressed to a practical level, Durability could be secured.

Further, by setting the amount of the cationic antistatic agent contained in the resin lid portion to 1 ppm or more, the electrification of the magnetic tape can be prevented, and the stable running property of the magnetic tape can be ensured. We were able to.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a magnetic recording tape cassette according to the present invention.

FIG. 2 is a schematic sectional view of a magnetic recording tape cassette according to the present invention.

FIG. 3 is a schematic view of a magnetic tape deposition apparatus.

[Explanation of symbols]

1 vacuum chamber, 2 non-magnetic support, 3 feed roll, 4
Take-up roll, 5 cooling can, 6, 7 guide roll, 8 crucible, 9 metal magnetic material, 10 electron gun, 13
Shutter, 14 Oxygen gas introduction pipe, 15, 16 exhaust port, 100 magnetic recording tape cassette, 101 upper shell, 102 lower shell, 103 lid part, 10
3a front lid, 103b back lid, 12
0 magnetic tape, 200 reel, 201 upper flange, 202 lower flange, 203 hub

Claims (5)

[Claims] 1. A magnetic recording tape cassette comprising a pair of upper and lower shells, wherein a pair of tape reels around which a magnetic tape is wound are rotatably housed, and the magnetic tape is stretched over the pair of tape reels. The magnetic recording tape cassette has an opening in a portion facing the stretched magnetic tape, and the opening is opened and closed by a resin lid portion that is rotatably supported. Part is a cationic antistatic agent 1 to
A magnetic recording tape cassette containing 100 ppm. 2. The magnetic recording tape cassette according to claim 1, wherein the cationic antistatic agent is a cationic surfactant. 3. The magnetic recording tape cassette according to claim 1, wherein the magnetic tape is a metal thin film magnetic recording medium. 4. The magnetic recording tape cassette according to claim 1, wherein the resin lid part comprises a front lid and a back lid. 5. The magnetic recording tape cassette according to claim 1, wherein the lid part made of resin is composed of only a front lid.