JPH03288386A - Tape cassette - Google Patents

Abstract

PURPOSE:To assure the reliability of high-density recording even under a highly corrosive environmental condition by disposing trap layers of a resin component having an amide group in a part near a magnetic tape stretched at least between both reels of a cassette. CONSTITUTION:Resins having an active N-H bond, such as -CONH- or -CONH2, as the amide group are effective as the trap layers 24, 25 of the cassette for, for example, 8-mm tapes. These resins include, for example, 4-nylon, 6-nylon, 66-nylon and the modified substances and copolymers thereof. Such cassette tape puts the high-density magnetic recording by the magnetic recording medium of a ferromagnetic metallic thin film type having a protective film into practica bility even in the severe environment where corrosive gases coexist.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a tape cassette containing a metal thin film type magnetic tape suitable for high-density magnetic recording.

Conventional Technology Magnetic recording, which is currently flourishing, is based on the magnetic differential type, and it is no exaggeration to say that it has developed around advances in the magnetic tape and magnetic head systems that exchange signals.

In order to continue to develop magnetic recording, it is essential to improve the recording density of the layers, and the transition from the conventional oxide-based to metal-based tape head systems is a prerequisite, and active efforts are being made in various fields. Development is underway.

Metal thin film magnetic tape has Co-N as a magnetic recording layer.
i-0 diagonally deposited film arranged in the form of a polymer film,
It is called ME tape, and is beginning to play a role in increasing the density of 8mm video.

Furthermore, such metal thin film magnetic tape is highly anticipated as an indispensable product for increasing the density of digital recording from analog recording, and is expected to solve various problems brought about by shortening the wavelength of recording signals, and solve the problems inherent in the material itself. Discussions are continuing to find solutions to the issues at a higher level.

Among the above, an important issue is how to impart durability to a magnetic recording layer with good smoothness in order to minimize spacing loss, which is a major problem with short wavelength signals. The problem is how to ensure overall stability when thinning the film and improving short wavelength characteristics, and how to take measures against the problem of deterioration over time due to corrosion.

The proposals that have been made so far to solve these problems can be summarized in the following items.

In other words, ■ Improving friction, wear, etc. by arranging minute protrusions on the magnetic recording layer [for example, IEE Transactions
ON MAGNETICS (IEEETRANSACTIO
NS ON M^GNETIC5) vo 1. M.A.
G21 N1115.1524-1526 (198
5).

JP-A-59-207422, JP-A-612848
See Publication No. 29, etc.], ■ Effective use of a partially oxidized layer to improve corrosion resistance, wear resistance, etc. without exposing the metal part responsible for magnetism [
For example, Japanese Patent Publication No. 57-2391, Japanese Patent Publication No. 57-2
9770, Japanese Patent Application Laid-open No. 153856/1983], ■ Harden the material structure of the magnetic recording layer itself to have good corrosion resistance [For example, see Japanese Patent Application Laid-open No. 591195
No. 32, JP-A No. 61-139920, etc.], ■ Avoid direct sliding between the magnetic recording layer and the magnetic head, etc.
The essential role of the magnetic recording layer itself and ensuring durability against sliding can be shared by providing another protective lubricant layer.
For example, JP-A-6093635, JP-A-61-1
No. 31231, Japanese Patent Application Laid-open No. 142525/1983,
JP-A-61-151830, JP-A-612423
23, JP 61-250825, JP 61-280019, JP 62-8325, JP 61-61444, etc.], ■ Any combination of the above proposals. has been adopted.

Magnetic tapes improved by the above techniques are generally placed in tape cassettes and put into practical use.

The vast majority of tape cassettes currently in practical use are assembled from molded synthetic resin parts, and the materials are made in accordance with various standards.

Appropriate improvements have been made to the design, ease of assembly, mechanical properties, weather resistance, etc., but especially for recent high-density recording applications, it is necessary to prevent foreign matter from entering the system and prevent problems such as dropouts and clogging. For the purpose of
Publication No. 9983.

Utility Model Publication No. 58-109875, Japanese Patent Application Publication No. 615487
No. 61-48481.

JP-A-61-162290, Utility Model Application No. 611181
See Publication No. 75, etc.].

The above-mentioned cassettes with good airtightness, specifically commercially available 8mm video, R-DAT, and broadcast format cassettes, are preferable in terms of improving the weather resistance of metal thin film type magnetic tapes, and This is believed to have helped improve the tape itself and made it possible to put it into practical use.

Problems to be Solved by the Invention However, the spread of video in recent years has been remarkable, and the scope of recording has expanded for both consumer and professional use. In addition to being exposed to various corrosive residues, such as H2S, SO
2,C1! 2. There is a growing demand for materials that can withstand practical use under harsher conditions, including exposure to NOx.

Even if the tape cassette system is completely harmless under normal usage conditions, in special environments where the above-mentioned debris is present in high concentration, even short exposure may cause signal loss or clogging. Problems such as triggering occurred, and improvements were desired.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide an improved tape cassette that makes it possible to ensure the reliability of high-density recording even under highly corrosive and special environmental conditions.

Means for Solving the Problems In order to solve the above-mentioned problems, the tape cassette of the present invention has a magnetic tape in which a trap layer made of a resin component having an amide group is stretched between at least both sides of the cassette. It is arranged in a part of the vicinity of .

Function: In the metal thin film type magnetic tape disposed in the tape cassette of the present invention, corrosive gas that diffuses and enters through the gaps existing in the tape cassette in a stored state is captured by adsorption reaction on the trap layer. Since the invading gases are protected by flowing toward the trap layer due to concentration gradient-controlled diffusion, there is no practical problem in deterioration of the magnetic tape side even in a highly corrosive gas atmosphere. It will keep it in good condition. The above-mentioned effect is particularly strong because the cassette is highly sealed and the gas inside moves by diffusion.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 5 is an enlarged sectional view of an ME tape that was placed in a tape cassette according to an embodiment of the present invention and whose practicality was evaluated. In FIG. 5, 1 is a polymer film such as polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, etc., and 2 is Ae 203. S io
2. Eu2O:+.

A fine particle preliminary inspection fabric layer coated with fine particles such as C, O, ZrO2, etc. 3 is Co-0, Co-Ni, Co-Cr.

Co-Ti, Co-5i, Co-Cr-Nb, Co-N
A magnetic recording layer made of a ferromagnetic metal thin film such as i-0,
4 is a 5i02 film, a plasma polymerized film, and a BN film.

A protective film such as a hard carbon film is arranged at an optimal thickness while taking into account spacing loss. 5 is a lubricating layer made of higher fatty acids, perfluorocarboxylic acids and their esters,
Lubricants such as perfluoropolyether. 6 is a so-called back coat layer in which fillers such as carbon black and calcium carbonate are dispersed and fixed in a resin to improve running properties.

The magnetic tape with the above configuration is 1i2 inch, 8mm,
Cut to either 3.8 mm or other specified width if necessary, and pass through leader tape and trailer tape.
After being wound on a reel to the required length, it is assembled into a cassette.

The tape cassette targeted in one embodiment of the present invention has a relatively good airtightness, and is currently used in large quantities.
Since it is difficult to obtain a sufficient degree of sealing with a tape cassette for an i2-inch home video tape without a back cover, which will be described later, a detailed explanation will be given in Fig. 6.
As shown in the external view of FIG. 7, this device is designed to have a hermetically sealed structure, such as those for 8 mm video and R-DAT.

FIG. 6 is an external view showing an 8mm video tape cassette, where 7 is a magnetic tape, 8 is a main case, 9 is a case A (hereinafter referred to as the lower half), and 10 is a case B (hereinafter referred to as the lower half).
(referred to as an upper half), 11 is a front lid that is pivotally supported on the upper half 10 so as to be openable and closable, and covers the front surface of the main body case 8. 1
2 is a rear cover for protecting the magnetic tape 7 that is placed in the drawer. FIG. 7 is an external view of a tape cassette for R-DAT, in which 13 is an upper half, 14 is a lower half, 15 is a front lid, and 16 is a rear lid.

A more specific example will be described in detail below.

The ME tape used to examine the effects of this example was a polyethylene terephthalate film with a thickness of 10 μm, and an average of 50 Sigh particles with a particle size of 100 A per 1 μm2.
After applying, apply 5X along a cylindrical can with a diameter of 1m.
Co-Ni (Ni; 20
% by weight) to a thickness of 0.1 μm, a hard carbon film with a thickness of 100 A was formed on it by DC plasma polymerization of methane gas, and then DuPont, which is commercially available as a perfluoropolyether carboxylic acid, was deposited on top of it by DC plasma polymerization of methane gas. Company-made “K”
RYTOX-157, FS-M" about 50A, and
Carbon black and calcium carbonate were mixed at a weight ratio of 1:4 on the side opposite to the magnetic layer, and the mixture was mixed with the polyester resin.
Disperse 100% by weight, mix with solvent, apply and dry,
．． An 8 mm wide tape with a 5 μm backcoat layer was used. This tape will be referred to as ME-A.

Next, the resin having an amide group, which is a requirement of the present invention, will be explained in detail.

As the amide group, those having an active N-H bond such as -CONH- or C0N82 are effective.

Examples of such resins having an amide group include nylon resins having an amide group in the main chain, such as 4-nylon and 6-nylon.
There are nylon, 60-nylon, and modified products and copolymers thereof. Examples of resins having amide groups in side chains include polyacrylamide, polymethacrylamide, and copolymers thereof. Also, there are reactants of vinyl polymers containing acrylic acid or methacrylic acid and amine compounds.

The above resin having an amide group can be used alone or in combination with other resins.

A method for forming a trap layer containing these resin components on a tape cassette is to apply a solution of the above resin to the required area and form a thin film on the cassette surface, or to form a thin film on the cassette surface, or to form a trap layer containing the above resin components alone or A mixture of other resins can be used as the cassette material, and the surface of the cassette itself can be used as a trap layer.

Low-molecular amide compounds, such as stearamide, are also effective as corrosive gas trapping agents.
In a composition that shows a sufficient trapping effect when forming a thin film alone or when added to a resin,
It was easy to fall off from the resin surface and had poor practicality.

(Example 1) FIG. 1 is a longitudinal sectional side view of the main parts of an 8 mm tape cassette used in a first example of the present invention.

In FIG. 1, 17 is an ME tape, and 18 is a Co--Ni-0 magnetic layer obtained by a vapor deposition method. 19 is a reel flange, 20 is an upper half, 21 is a lower half, 22 is a front lid, 23
is the posterior lid. 24 and 25 are trap layers.

- That is, in this example, ABS is used as the cassette material.
Resin (acrylonitrile/butadiene/styrene resin)
As shown in the figure, the trap layer is placed on the inside and part of the side surfaces of the front lid and rear lid, and the effects of forming the trap layer on various materials using the coating method will be described. The materials used are shown below.

Modified nylon: Methoxymethylated nylon (trade name, Torezin M, manufactured by Teikoku Sangyo) Nylon copolymer: Nylon 6/66/610 (trade name, Amilan CM, manufactured by Toshi) Polyacrylamide, polymethacrylamide: Radical ME by using these cassette parts with Kinzo trapping agent according to the polymerization method.
-Comparative example with cassette incorporating A tape and without trap layer, 2 rolls each at 35°C, 85~
After leaving it in a desiccator at 9o%RH, HCe, 3ppm for 4 hours, a commercially available 8mm video (Sony, EV-8
900), recording and reproduction was performed in a range of 1 m from the front and back of the position corresponding to the tape pull-out section.

The conditions and results are summarized in Table 1. In the table, dropout was evaluated by increase rate, and clogging was evaluated by total time, and the worse value of the two volumes was shown. Combinations were also carried out using ME tapes (referred to as ME-B) that were prepared under the same conditions as ME-A, except that some cassettes were not provided with a hard carbon film.

(Margins below) As can be seen from the results in Table 1, ME tapes (tape cassettes 1 to 4) used in cassettes with trap layers are more sensitive to corrosive environments than tapes 5 and 6. But you know you'll be protected.

However, in the case of ME Tape 7.8 without a hard carbon film, even in the case of a cassette with a trap layer, dropouts and clogging increased, and the effect of the trap layer was not sufficient, making it unsatisfactory. No results have been obtained.

This is thought to be because there is no significant difference between the adsorption reactivity of the trap layer and the adsorption reactivity of the ME tape without a hard carbon film, and the corrosive gas does not selectively adsorb and react with the trap layer. That is, the present invention provides great effects when used in an ME tape having a protective film whose adsorption reactivity is somewhat lower than that of the trap layer.

(Example 2) The modified nylon used in the example was coated with
The tape ME-A, which has a protective film made of a hard carbon film, was installed at different parts with a thickness of 0 micron and heated at 20°C.
The cassette coating conditions were determined by exposing the recording and reproducing characteristics to an environment of 3.8 ppm of Ce2 guff at 65-70% RH and 1.6 ppm of SO2 gas at 35°C and 90% RH for 24 hours. The results are summarized in Table 2.

In Table 2, the cassette 2A is the part a and part b of the front cover 22 in FIG.
As shown in section C and section C in FIG. 3, the side surface of the lower half was coated with a length of 10wn at section J of the surface facing the stretched tape. Cassette 2B is j in Figure 3.
The conditions were the same as those for cassette 2A, except that the coating length was 30 Wl. The cassette 2C has a front cover 22.
Part a, part b.

The coating length of the C part and the J part is 30+mn, and the side surface 30IIn corresponding to the J part of the upper half is coated. In addition to the conditions of cassette 2C, cassette 2D has a coating applied to portion g of the upper half and portion d of the lower half. In the cassette 2E, parts a and b of the front M22 and parts e and d of the lower half are coated.

In the cassette 2F, only the side portion of the tape winding portion of the reel flange, the i portion (this is for both reels), is coated. Cassette 2G has upper half and lower half d.

Parts e, f, and g are coated. Cassette 2
H is a product in which only the d and 2g portions of the upper half and lower half are coated.

(Margins below) Table 2 shows that depending on the coating area, even if the modified nylon is coated, a sufficient effect may not be obtained. In other words, although tape cassettes 6 to 8 are considerably improved over tape cassette 9 without coating, there is a coating layer, that is, a trap, in a region near the magnetic tape stretched between both reels. It is clear from Table 2 that it is preferable that layers are arranged.

(Example 3) Similar to Example 1, ABS resin was used as the cassette material, and a modified nylon coating film was formed at the same location,
In addition, the effect of changing the surface area of the coated front lid and rear lid will be explained. Cassette 3A has a standard planar configuration with a coating of 15 microns, and cassette 3B has 10 grooves of 100 microns deep and 50 microns wide on the surface, similar to the above. 15
Cassette 3C is 1m2 with a micron coating.
A coating film of 15 microns was also formed on a surface with 10 recesses each having a diameter of 50 microns.

Tape ME-A, which has a protective film made of a hard carbon film, was installed in the above cassette and exposed to a corrosive atmosphere containing 10 ppm and 2 ppm of nitrous gas (NO2) at 30°C and 80% RH for 1 hour for recording and playback. Table showing the results of investigating the characteristics.
They are summarized in 3.

(Margins below) Within the range of the representative examples shown in Table 3, there is almost no difference in the constituent surface area of the trap layer, but naturally, if the area becomes too small, the effect weakens.

As a rough guide, the surface area should be considered and designed to be approximately the same as the surface area of a magnetic tape in an open state without being wound.

Please note that this is just a rough guideline, taking into account the degree of sealing of the cassette, the actual exposure atmosphere, the exposure time, and the position of the open part changing as the tape is fed. Optimization can be done as appropriate depending on the cast area, the structure of the cassette, the degree of sealing, etc., and also taking economic efficiency into account.

Preferable methods for changing the surface area include changing the surface roughness of the cassette parts, placing fine ribs as reinforcement, and adding fine fillers to the coating film of the trapping agent, as appropriate. It has been confirmed that it can be adopted and its effects are sufficient.

(Example 4) FIG. 4 shows a longitudinal cross-sectional side view of the main parts of the 8 mm skein and soto used in the fourth example. The same parts as in FIG. 1 are shown with the same numbers. In this embodiment, a case in which a material having a trapping effect on the white body of a cassette component is used will be described in detail. Tape ME-A is molded using a mixed polymer of ABS resin (acrylonitrile, butadiene, styrene resin) and nylon resin (nylon 6) as the cassette material, placed in different parts, and has a protective film made of hard carbon film on the cassette. The results were obtained by exposing the sample to a corrosive atmosphere containing 6 ppm of nitrite gas (NO2) and 9 ppm of sulfur dioxide gas (SO2) at 35°C and 80 to 85% RH for 2 hours, recording and reproducing the characteristics. are summarized in Table 4 for each cassette condition.In Table 4, cassette 4A has a front cover in Fig. 7, cassette 4B has a front cover and rear cover, and cassette 4C has a front cover.
uses the above resin for the front lid, back lid, upper half, and lower half,
The same ABS resin as in Example 1 was used for other parts.

In addition, as a comparative example, a cassette made of ABS resin was
shall be.

As shown in Table 4, tape cassette 3 has a front cover,
It is used for the rear lid, upper half, and lower half, but only for the front lid.
Or, there is no big difference in cost and dimensions compared to when it is used for both the front and back lids.

This is within the design range in consideration of physical properties such as mechanical properties.

Furthermore, the composition of the resin component having a trapping effect is determined based on design considerations such as storage characteristics, compliance with standards, and physical properties.

(Example 5) In this example, similarly to Example 4, a case will be described in detail in which a modified ABS resin having a trapping effect is used for the cassette component itself.

The modified ABS resin was used under the following conditions. 40 parts of a monomer mixture consisting of styrene/acrylonitrile-70/30 in the presence of 60 parts of copolymer rubber having a composition of acrylonitrile/butadiene=10/90 (weight ratio)
30 parts of the graft copolymer obtained by polymerizing 1 part and styrene/acrylonitrile/acrylic acid = 65/32/3
(Weight ratio) Formed using a polymer having an amide group obtained by reacting 42 parts of copolymer and 28 parts of polyethylene glycol diamine (average molecular weight 400).The cassette has a protective film made of a hard carbon film. The tape ME-A was installed and exposed for 45 hours to a corrosive environment of 1 ppm SO2 gas at 23°C, 70% RH and a corrosive environment of C<2 ppm gas at 40°C, 83% RH, and the recording and reproducing characteristics were investigated. Table 5 summarizes the conditions for each part of the cassette where the material is used.

Cassette 5A used the front lid, cassette 5B had the front lid and rear lid, cassette 5c had the front lid, rear lid, upper half, and lower half, and cassette 5D had the upper half using the materials having the compositions described above. As a comparative example, a cassette made of ABS resin is designated as 5E.

(Margin below) As is clear from Table 5, it can be seen that a sufficient effect may not be obtained depending on the area where it is used.In the case of tape cassette 4, which uses a material that has a trap effect only in the upper and lower halves, , although there is a considerable improvement, the improvement effect is small, and it is clear from Table 5 that it is preferable to arrange the trap layer near the magnetic tape stretched between both reels.

Example b (Implementation meeting) An example carried out using R-DAT shown in the external view in Fig. 7 will be described in detail.A trap layer was arranged under appropriate conditions in the front cover 15 and rear cover 16 portions in Fig. 7. Incorporate tape ME-A with a protective film made of hard carbon film into the cassette, and
, 80%RH, hydrogen sulfide ()I=s') 4ppm,
The rate of change in block error rate was measured after 4 hours of exposure to a corrosive environment of 3 ppm hydrogen chloride (HC&2).

Cassette 6A is a case where the front lid is painted with modified nylon.
Cassette 6B is a case where a mixed resin of ABS and nylon is used for the front lid and rear lid, and cassette 6C is a case where the modified ABS resin used in Example 5 is used for the front lid and rear lid.

As a comparative example, a cassette made of ABS resin is designated as 6D.

The comparison results between the above cassette and comparative example are shown in Table-
They are summarized in 6. The R-DAT used in the measurements was a testing machine with the same functions as commercially available products, and was evaluated by making the head easy to clean, making it easy to initialize each measurement, and eliminating errors due to measurement order. It is.

(Margins below) As can be seen from Table 6, tape cassettes 1 to 3 are at a level where it can be said that there is almost no change.
It can be seen that it is also effective.

Effects of the Invention As described above, according to the present invention, high-density magnetic recording using a ferromagnetic metal thin film magnetic recording medium having a protective film can be put to practical use even in a harsh environment where corrosive gases exist. The industrial value of the present invention is great.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional side view of the main parts of an 8 mm tape cassette used in the first embodiment of the present invention, and FIG.
FIG. 3 is a perspective view of the main part of the lower half of the cassette for millimeter tape, FIG. 4 is a longitudinal side view of the main part of a cassette for 8 mm tape according to another embodiment, and FIG. 5 is a view of the present invention. FIG. 6 is an external view of an 8 mm video magnetic tape cassette, and FIG. 7 is an external view of a magnetic tape cassette for R-DAT. 1... Polymer film, 3... Magnetic recording layer consisting of a ferromagnetic metal thin film, 4... Protective film,
7... Magnetic tape, 8... Body case, 11.15.22... Front lid, 12, 16.2
3... Rear lid, 13... Upper half, 14
...Lower half, 17...ME tape,
24.25...Trap layer.

Claims (1)

[Claims] A tape cassette in which a magnetic recording layer is a ferromagnetic metal thin film disposed between two reels, and further contains a magnetic tape having a protective film on the magnetic recording layer and a reel wound with the magnetic tape. A tape cassette characterized in that a trap layer made of a resin component having an amide group is provided at least in a part of the vicinity of the magnetic tape stretched between both reels.