JPH0830930A - Polishing tape - Google Patents

Abstract

PURPOSE:To make it possible to improve polishing effect while suppressing polishing flaws and to provide a polishing tape adequate for use in polishing and cleaning of magnetic tapes, magnetic heads, etc., to be used for high-density recording by improving the structure of this polishing tape. CONSTITUTION:This polishing tape is composed of a first polishing layer 2 formed on a base 1 and second polishing layers selectively formed on this layer 2. The base 1 is a film of an arbitrary thickness consisting of a high-polymer material. The layer 2 is a flat layer consisting of a polishing agent and binder and is formed by dispersing the polishing agent and the binder in a solvent and applying the a. over the entire surface of the base. The layers 3 are composed of the polishing agent and the binder like the layer 2 but an important requirement is that the layers 3 are selectively formed on the layer 2. The polishing surface of the polishing tape is brought into contact with the surface to be polished of the magnetic tape or the magnetic head and the polishing tape is slid in such a manner that the surface to be polished crosses the striped patterns of the polishing surface in order to execute polish and cleaning with the polishing tape 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 polishing tape used for polishing and cleaning magnetic tapes and magnetic heads.

[0002]

2. Description of the Related Art In a magnetic tape or a magnetic head, dust, debris, and fallen objects that have fallen off from the magnetic layer are not present on the surface of the magnetic layer or on the magnetic head during use. Often adheres to the tape sliding surface. If the foreign matter attached to the magnetic tape or the magnetic head is left as it is, any of them causes a dropout, leading to a reduction in the SN ratio. For this reason, it has been conventionally practiced to use a polishing tape and bring it into sliding contact with a magnetic tape or a magnetic head to grind and remove foreign matter attached thereto.

Most of the polishing tapes used for polishing and cleaning such magnetic tapes and magnetic heads have a two-layer structure in which one polishing layer is formed on a support. The polishing layer is composed of a polishing agent and a binder, and is formed, for example, in a flat layer or a fine hexagonal pattern. The performance of this polishing tape is determined by the pattern shape of the polishing layer, the material and size of the polishing agent, and the like.

[0004]

By the way, when polishing or cleaning a magnetic tape or a magnetic head,
The polishing tape requires a certain level of polishing power. However, in the case of the above-mentioned polishing tape in which only one polishing layer is formed, when the polishing force is increased, the problem of polishing scratches occurs accordingly. Considering this, the present situation is that the polishing power cannot be sufficiently increased.

For example, in order to increase the polishing power of the polishing tape, it is advantageous to use, as the polishing agent, one having a high hardness and a small count, that is, one having a large size. On the contrary, polishing scratches are more likely to occur when an abrasive having a high hardness is used, and particularly remarkable when an abrasive having a small count is used. As described above, the improvement of the polishing property and the prevention of the polishing scratches are contradictory.

Specifically, as the polishing agent for the above polishing tape, Al ₂ O ₃ powders # 4000 and # 6000 or SiC powders # 4000 and # 6000 are generally used.

Since SiC powder has a relatively high hardness, it can be said that # 4000 of this SiC powder is preferable if only the polishing property is prioritized. However, the polishing tape using this has a problem of occurrence of polishing scratches. On the other hand, # 6000 of Al ₂ O ₃ powder is suitable for suppressing the occurrence of polishing scratches.
The polishing tape using this is inferior in polishing property. In addition to this, no matter what combination of material and count, no improvement in polishing property and prevention of polishing scratches are satisfied, and in the configuration in which only one polishing layer is formed, both of these conditions are satisfied. It can be said that compatibility is quite difficult.

In the field of magnetic recording, it is considered that the recording density will be further increased in the future, and the precision of the contact state of magnetic tapes and magnetic heads is also strictly required. For this reason, it is necessary for the above-mentioned polishing tape for cleaning and polishing to perform high-precision polishing while suppressing polishing scratches, and it is possible to improve polishing property and prevent polishing scratches at a high level. Is required.

Therefore, the present invention has been proposed in view of such conventional circumstances, and can improve the polishing performance while suppressing polishing scratches, and is useful for polishing and cleaning magnetic tapes and magnetic heads used for high density recording. The purpose is to provide a suitable polishing tape for use.

[0010]

In order to achieve the above object, the inventors of the present invention have conducted extensive studies, and as a result, in order to achieve both improvement in polishing property of a polishing tape and prevention of polishing scratches, It was not enough to control only the material and size of the agent, leading to the idea that the structure itself needs to be changed.

That is, in the polishing tape of the present invention, a first polishing layer containing polishing powder is formed on a support, and a second polishing layer containing polishing powder is formed on the first polishing layer. It is characterized by being selectively provided.

The first polishing layer is formed on the entire surface of the support.

Further, the second polishing layer is characterized by being formed in a stripe pattern.

As shown in FIG. 1, the polishing tape of the present invention comprises a first polishing layer 2 on a support 1 and a second polishing layer selectively provided on the first polishing layer 2. It is composed of three.

The support 1 is a film made of a polymer material such as polyethylene terephthalate or polyethylene naphthalate and having an arbitrary thickness.

The first polishing layer 2 is a flat layer composed of an abrasive and a binder. The first polishing layer is formed by dispersing an abrasive and a binder in a solvent and applying the abrasive coating to the entire surface of the support by a coating method such as a gravure printing method. As the polishing agent, SiC powder, A
I ₂ O ₃ powder of # 1000 to 15000 is used. Further, as the binder and the solvent, any of those conventionally used in the polishing tape can be used and is not limited at all. Further, the film thickness of the first polishing layer is suitably 2.0 to 10.0 μm.

The second polishing layer is composed of a polishing agent and a binder, like the first polishing layer. Particularly, in the case of the second polishing layer, the second polishing layer is selectively provided on the first polishing layer. Is important.

That is, as shown in FIG. 1, in the second polishing layer, for example, rod-shaped polishing layers are arranged at arbitrary intervals and the running direction when the polishing tape is used (the direction of arrow A in the figure). It is formed in a striped pattern continuous with.
A plan view of this striped pattern is shown in FIG. Here, it is desirable that the height a, the width b, the interval c, and the inclination angle (angle with respect to the running direction A of the polishing tape) θ of the rod-shaped polishing layer fall within the following ranges.

A = 1.5 to 10 μm b = 0.25 to 1.00 mm c = 0.25 to 1.00 mm θ = 15 to 90 ° The rod-shaped polishing layer has a rectangular cross section shown in FIG. However, the cross-sectional shape may be either semicircular as shown in FIG. 3 or trapezoidal as shown in FIG. 4 as long as a striped pattern can be formed.

The second polishing layer is also formed by the gravure printing method or the like, like the first polishing layer. in this case,
As the gravure roll, a gravure roll having a groove formed in a pattern corresponding to the pattern of the second polishing layer is used. As the abrasive, binder and solvent, any of those used in the first polishing layer can be used. Therefore, the polishing paint used for forming the first polishing layer may be used as it is for forming the second polishing layer.

In order to polish and clean the magnetic tape and the magnetic head with the polishing tape having the above-mentioned structure, the surface (polishing surface) of the polishing tape on the side of the polishing layer is polished and cleaned. The surface to be polished (surface to be polished) is brought into contact with the surface, and the polishing tape is slid so that these surfaces to be polished cross the stripe pattern of the surface to be polished.

At this time, only the second polishing layer having a stripe pattern, which is the convex portion of the polishing surface, directly contacts the surface to be polished, and is in a so-called line contact state with the polishing surface.

When sliding in this state, in addition to the polishing action of the polishing agent, the edges of the convex portions on the polishing surface amplify the polishing action, and effective polishing is performed.

Further, the concave portion of the polishing surface works to remove the air layer generated when the polishing surface and the polishing surface are slid at high speed, and the adhesion between the polishing surface and the polishing surface is enhanced.
The polishing action is further improved.

Therefore, even when using an abrasive having a relatively large count (abrasive having a small size), which is advantageous for suppressing polishing scratches, but difficult to obtain the polishing property, a large polishing is performed. The effect is obtained. That is, it is possible to achieve both improvement of polishing property and prevention of polishing scratches, which was difficult with a polishing tape of a type in which a surface to be polished and a polishing surface are in surface contact, for example, a polishing tape having a flat polishing layer formed on a support. However, it will be easily realized.

Particularly, when the inclination angle of the striped pattern of the second polishing layer is set to a relatively small angle within the range of 15 to 90 °, the occurrence of polishing scratches can be suppressed. As a result, even when using a polishing agent with a small count (abrasive with a large size), polishing scratches are suppressed,
It is advantageous because the polishing scratches are prevented and the polishing property is improved. When the inclination angle of the striped pattern of the second polishing layer is set within the above range, the occurrence of polishing scratches can be suppressed because the polishing condition changes and the polishing powder generated by polishing becomes the polishing tape. It is considered that the particles are easily trapped, and the occurrence of polishing scratches caused by sliding between the polishing surface and the surface to be polished through the polishing powder is reduced.

[0027]

A first polishing layer containing polishing powder is formed on a support, and a second polishing layer containing polishing powder is formed on the first polishing layer.
When the polishing surface of the polishing tape on which the polishing layer is selectively provided is brought into contact with the surface (surface to be polished) of the magnetic tape or the magnetic head to be polished or cleaned, the surface to be polished has a convex surface. Only the second polishing layer, which is a part, directly contacts.

When the polishing surface and the surface to be polished are slid in this state, the polishing action of the polishing agent as well as the edges of the convex portions of the polishing surface amplify the polishing action, and effective polishing is performed.

Further, the concave portion of the polishing surface functions to remove the air layer generated when the polishing surface and the polishing surface are slid at high speed, and the adhesion between the polishing surface and the polishing surface is enhanced. The polishing action is further improved.

Therefore, even when an abrasive having a relatively large count (abrasive having a small size), which is advantageous for suppressing polishing scratches but difficult to obtain abrasiveness, is used, large polishing is performed. The effect is obtained. That is, it is possible to achieve both improvement of polishing property and prevention of polishing scratches, which was difficult with a polishing tape of a type in which a surface to be polished and a polishing surface are in surface contact, for example, a polishing tape having a flat polishing layer formed on a support. However, it is easily realized.

[0031]

EXAMPLES Specific examples of the present invention will be described below, but it goes without saying that the present invention is not limited thereto.

Example 1 First, a polishing coating material (polishing agent Al ₂ O ₃ powder) for forming the first polishing layer and the second polishing layer was prepared as follows.

Composition of abrasive coating 100 parts by weight of Al ₂ O ₃ powder (however, the count is any of # 2000, # 4000, # 6000, # 8000.) 15 parts by weight of polyurethane (trade name N-3127) (solid Amount) Vinyl chloride copolymer (VAGH) 30 parts by weight (solid amount) Methyl ethyl ketone 80 parts by weight Cyclohexanone 80 parts by weight Various materials are charged in a ball mill pod according to the above composition, mixed for about 48 hours, and then filtered and defoamed. did. And
An abrasive coating was prepared by adding 5 parts by weight of a polyisocyanate curing agent and stirring for about 30 minutes.

Then, the polishing coating material thus prepared was applied evenly on a support made of polyethylene terephthalate in a thickness of 7 μm by a gravure printing method to give about 80 μm.
It was dried at a temperature of ° C. Subsequently, it was cured by leaving it in a constant temperature bath kept at 60 ° C. for about 20 hours to form a first polishing layer.

Next, the above-mentioned polishing coating material is applied onto the thus formed first polishing layer in a stripe pattern by a gravure printing method and dried under the same conditions as in the case of the first polishing layer. Then, the second polishing layer was formed by curing.
The striped pattern is a shape in which rod-shaped polishing layers each having a quadrangular cross section with an inclination angle of 90 ° are connected at an interval of 0.3 mm. The rod-shaped polishing layer has a height of 3
μm, width is 0.5 mm.

Then, as described above, the raw tape tape on which the first polishing layer and the second polishing layer were formed was cut into a predetermined width to prepare a polishing tape.

Example 2 In preparing a polishing coating composition, instead of Al ₂ O ₃ powder as a polishing agent, SiC powders # 2000, # 4000,
A polishing tape was prepared in the same manner as in Example 1 except that either # 6000 or # 8000 was used.

Comparative Example 1 A polishing tape was prepared in the same manner as in Example 1 except that the second polishing layer was not formed.

Comparative Example 2 In preparing a polishing coating composition, SiC powders # 2000, # 4000, instead of Al ₂ O ₃ powder were used as abrasives.
A polishing tape was prepared in the same manner as in Example 1, except that either # 6000 or # 8000 was used and the second polishing layer was not formed.

Micro floppy disks were polished with each of the polishing tapes prepared as described above, and the polishing property and polishing scratches were evaluated.

The polishing property was evaluated by measuring the number of dropouts of the ground micro floppy disk. When the number of dropouts was small, it was determined that the polishing was sufficient, and when the number of dropouts was large, it was determined that the polishing was insufficient.

The polishing scratches were investigated by observing the floppy disk surface with an optical microscope (50 times).

Tables 1 to 4 show the results of evaluation of the polishing property and polishing scratches.

However, Table 1 is the polishing tape prepared in Example 1, Table 2 is the polishing tape prepared in Example 2, Table 3 is the polishing tape prepared in Comparative Example 1, and Table 4 is the polishing tape prepared in Comparative Example 2. Is the evaluation result of. In the table, in the column of abrasivity, ⊚ has sufficient abrasivity, ◯ has a practical abrasivity, Δ is insufficient abrasivity, and × is abrasivity. Each case is not practical. Also,
In the column of polishing scratches, ○ indicates that no polishing scratches have occurred, Δ indicates that some polishing scratches have been observed but is at a practical level, and × indicates that polishing scratches have occurred remarkably and cannot be put to practical use. Respectively.

[0045]

[Table 1]

[0046]

[Table 2]

[0047]

[Table 3]

[0048]

[Table 4]

First, Comparative Example 1 in which the polishing layer was not formed
Looking at the evaluation results (Tables 3 and 4) of the polishing tape of Comparative Example 2, it is advantageous to use SiC powder having a hardness higher than that of Al ₂ O ₃ powder in terms of the polishing property. It can be seen that the smaller the size, that is, the larger the size, the better the polishing property.
On the contrary, polishing scratches are more likely to occur when SiC powder having high hardness is used, and are particularly remarkable when a powder having a small count is used. That is, the improvement of the polishing property and the prevention of the polishing scratches are in conflict with each other.

In this case, no matter which combination of powder and count is used, those having excellent abrasiveness are likely to cause polishing scratches, and those having suppressed polishing scratches have insufficient abrasiveness. However, none of them have good polishing properties and polishing scratches.

On the other hand, looking at the evaluation results (Tables 1 and 2) for the polishing tapes of Examples 1 and 2 having the second polishing layer formed, the material of the polishing agent, the count and the polishing property are shown. The relationship between the polishing scratches is the same as that of the polishing tapes of Comparative Examples 1 and 2. However, compared with the polishing tapes of Comparative Example 1 and Comparative Example 2, the polishing scratches are about the same, but the polishing performance is quite good even when an abrasive having a relatively large count is used. . And Al
_{The 2} O ₃ powder has both # 4000, # 6000, and # 8000, and the SiC powder has both # 6000 and # 8000, which are both abrasive and abrasive.

From this, in the polishing tape, the first
It has been found that the structure in which the second polishing layer is selectively provided on the polishing layer is advantageous in improving polishing performance while suppressing polishing scratches.

Investigation of Inclination Angle of Second Polishing Layer Next, in order to examine the optimum pattern shape of the second polishing layer, the inclination angle was variously changed and the polishing property and polishing scratch were evaluated.

[0054] Al ₂ O ₃ powder of # 2000 as an abrasive
Using, the polishing tape was prepared in the same manner as in Example 1 except that the inclination angle of the striped pattern of the second polishing layer was changed as shown in Table 5, and the polishing properties and polishing scratches were evaluated. The results are shown in Table 5.

[0055]

[Table 5]

As can be seen from Table 5, among the characteristics of the polishing tape, especially the polishing scratches change depending on the inclination angle of the second polishing layer. And the inclination angle is 45 °,
When the angle is preferably smaller than that, polishing scratches can be suppressed even when the polishing agent (# 2000) having such a small count is used.

From this, it was found that adjusting the tilt angle when forming the second polishing layer made it easier to improve the polishing performance while suppressing polishing scratches.

[0058]

As is apparent from the above description, the polishing tape of the present invention is the first tape containing the polishing powder on the support.
Since the second polishing layer containing the polishing powder is selectively provided on the first polishing layer, it is possible to significantly improve the polishing performance while suppressing the occurrence of polishing scratches. Is possible. Therefore, it can be said that it is suitable for polishing and cleaning of magnetic tapes and magnetic heads used for high density recording.

[Brief description of drawings]

FIG. 1 is a perspective view showing one structural example of a polishing tape to which the present invention has been applied.

FIG. 2 is a plan view of the polishing tape.

FIG. 3 is a perspective view showing another configuration example of the polishing tape to which the present invention has been applied.

FIG. 4 is a perspective view showing still another configuration example of the polishing tape to which the present invention has been applied.

[Explanation of symbols]

 1 Support 2 First Polishing Layer 3 Second Polishing Layer

Claims (3)

[Claims] 1. A first polishing layer containing polishing powder is formed on a support, and a second polishing layer containing polishing powder is selectively provided on the first polishing layer. A polishing tape characterized by the above. 2. The polishing tape according to claim 1, wherein the first polishing layer is formed on the entire surface of the support. 3. The polishing tape according to claim 1 or 2, wherein the second polishing layer is formed in a stripe pattern.