JPH0671550A - Surface abrasive tape for magnetic disk - Google Patents

Abstract

PURPOSE:To secure a uniform surfacing property by containing a zircoaluminate compound in an abrasive layer. CONSTITUTION:A surface abrasive tape being available in a magnetic disk grinding attachment with a structure consisting of a magnetic disk 1, a magnetic tape 2, two guide rolls 3a, 3b, a backup roll 4 and a slit air nozzle 5 has a supporter and an abrasive layer formed on this supporter. This abrasive layer consists of an abrasive grain and a bonding agent. A zircoaluminate compound with a structure being shown in a formula is contained in this abrasive layer. With this constitution, the extent of affinity between the abrasive grain and the bonding agent is enhanced, and bonding strength in both of them is well improved, whereby surface hardness on the abrasive tape becomes increased. In consequence, a higher abrasive capacity is kept up, thus a surface of the magnetic disk is uniformly ground in this way.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface polishing for a magnetic disk, which is used for surface polishing for smoothing a recording image of the magnetic disk when manufacturing a magnetic recording medium such as a flexible magnetic disk and a magnetic tape. Regarding tape.

[0002]

2. Description of the Related Art In recent years, magnetic recording media such as flexible magnetic disks and magnetic tapes have been required to have a higher density. Therefore, development of ultra-smooth media design technology has been strongly desired. Usually, in a magnetic disk having a magnetic recording layer composed of magnetic powder and a binder on a non-magnetic support, the surface of the magnetic recording layer is polished in the circumferential direction in order to further improve its surface property. Processing is done. By performing such a surface polishing treatment, the recording / reproducing spacing loss between the magnetic head and the magnetic disk can be significantly reduced, and as a result, the magnetic disk having excellent running stability as well as electromagnetic conversion characteristics. Is obtained.

The surface of the magnetic disk in the circumferential direction is polished by using a polishing tape provided with a polishing layer comprising a fine particle having a polishing property and a binder on one surface of a long support. It is common to be told. A magnetic disk surface polishing apparatus is used when performing surface polishing processing on a magnetic disk using such a polishing tape. In this apparatus, the polishing tape is pressed against the surface of a magnetic disk rotating at high speed by a backup roll having elasticity, and as a result, minute projections existing on the surface of the magnetic layer are removed and surface polishing is achieved.

[0004]

In the case of polishing the surface of a flexible magnetic disk, if the binding force of the binder to the abrasive particles is not sufficient, the abrasive particles will be shed, inducing scratches, or polishing particles. Was adhered to the disk surface, resulting in a marked deterioration in quality, which was a major problem.

The present invention has been made in view of the above situation. That is, it is an object of the present invention to provide a surface polishing tape for a flexible magnetic disk which does not cause abrasive particles to be shed when the polishing tape is used for polishing.

[0006]

According to the present invention, there is provided a support and a polishing layer formed on the support, the polishing layer comprising abrasive particles and a binder for surface polishing of a magnetic disk. In the tape, a surface-polishing tape for magnetic disk containing the zircoaluminate compound having the following structure in the polishing layer is obtained.

[0007]

In the present invention, as shown in FIG. 2, when the surface hardness of the polishing tape is observed by taking the horizontal axis as an example and the comparative example and the vertical axis as a minute hardness, the surface hardness of the polishing tape is zirco aluminum. The addition of the nate coupling agent enhances the affinity between the abrasive particles and the binder, and increases the binding force between the two to increase the affinity. Therefore, it is possible to obtain a polishing tape which has a high polishing ability even under the pressure applied during the contact polishing of the polishing tape and the magnetic disk, and which has a uniform polishing ability without shedding. Therefore, by polishing a magnetic disk using the polishing tape according to the present invention,
The surface polishing property is not deteriorated, and the desired polishing time can be shortened as shown in FIG. 3, so that the production efficiency is improved.

[0008]

Examples As the support which can be used in the present invention, there are long films of polyethylene terephthalate, polyacetate, polyimide and the like, and any of them may be used. The abrasive particles may be fine powders having a Mohs hardness of 6 or more, such as fused alumina, silicon carbide, chromium oxide, α-
Examples thereof include iron oxide, diamond, silicon oxide and titanium oxide. The average particle size of the fine powder is 0.01 to 10 μm.
m, preferably 0.3 to 3 μm.
As the binder, a commercially available resin can be used. For example, as the binder used in the present invention, vinyl chloride-vinyl acetate-vinyl alcohol copolymer, epoxy resin, phenoxy resin, vinyl chloride-
Examples thereof include vinyl propionate copolymers, vinyl chloride-acrylic acid ester copolymers, vinyl chloride-vinyl acetate-maleic acid copolymers, polyvinyl butyral resins, acrylonitrile-butadiene copolymers and polyurethane resins. The zircoaluminate-based coupling agent used in the present invention has the following structure,
_{- (CH 2) 2 NH 2} , - (CH 2) 4 COOH, - (C
_{H 2) 12 CH 2, -} (CH 2) 2 SH, - (CH 2) 12 CH 3
Compounds having a functional group such as The amount of the coupling agent added is 0.1 to the abrasive particles.
It may be in the range of 5 wt%, preferably 1-3 wt
It may be in the range of%.

In order to compare the polishing tape according to the present invention with the conventionally used polishing tape, a performance comparison test was conducted between a sample obtained by carrying out the present invention and a conventional comparison sample.

Example 1 (Paint) 80 parts by weight of fused alumina (average particle size 0.5 μm). Polyurethane resin (Tg 25 ° C.) 6 parts by weight (solid content). Epoxy resin 14 parts by weight (solid content). Amino zircoaluminate propylene glycol 2.0 parts by weight. Methyl ethyl ketone / toluene 90 parts by weight / 90 parts by weight. After kneading the above composition in a ball mill for 50 hours, 4 parts by weight (solid content) of an isocyanate compound (Coronate L manufactured by Nippon Polyurethane Co., Ltd.) was added and further kneading for 1 hour to obtain a coating material. This was placed on a polyethylene terephthalate (PET) film having a thickness of 50 μm and the polishing layer after drying had a thickness of
It is coated and dried to a thickness of μm, slit into a width of 1 inch, and wound around a core with an inner diameter of 6 ″ for 100 m.
The sample was cured at 72 ° C for 72 hours.

Comparative Example 1 A sample was obtained in the same manner as in Example 1 except that the zircoaluminate coupling agent was used when forming the polishing layer in Example 1. As shown in FIG. 1, each sample obtained in the above-mentioned examples and comparative examples was subjected to magnetic disk polishing having a mechanism including a magnetic disk 1, a polishing tape 2, guide rolls 3a and 3b, a backup roll 4, and a slit air nozzle 5. The flexible magnetic disk having a diameter of 3.5 ″ was mounted on the apparatus and subjected to surface polishing treatment under the treatment conditions shown in Table 1.

[Table 1] The relationship between the polishing time and the glossiness of the magnetic disk surface when used is shown in FIG. Here, the surface glossiness of the magnetic disk was evaluated by a gloss meter.

Using the magnetic disks obtained by using the respective polishing tapes, 100 sheets for each sample, and 200 sheets in total, the surface of the magnetic disks was visually observed during the surface polishing to examine the scratch occurrence rate. Further, a track quality inspection was conducted under the conditions shown in Table 2.

[Table 2] Table 3 shows the scratch occurrence rate and the track quality inspection result.

[Table 3] That is, in the visual inspection of the surface of the magnetic disk and the track quality inspection of the missing error, the example clearly shows the desired surface roughness without the occurrence of scratches due to the shedding and polishing of the abrasive particles.

[0013]

As described above, by using the polishing tape of the present invention, it is possible to obtain uniform surface property without the abrasive particles being shed during surface polishing. Further, the polishing time required for obtaining the desired surface roughness is short. Therefore, it becomes possible to produce a high-quality magnetic disk, and the production efficiency of the magnetic disk is improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing a magnetic disk surface polishing apparatus used for evaluating a magnetic disk surface polishing tape in Examples of the present invention and Comparative Examples.

FIG. 2 is a diagram showing minute hardness in Examples and Comparative Examples.

FIG. 3 is a diagram showing changes in required polishing time and gloss in Examples and Comparative Examples.

[Explanation of symbols]

 1 magnetic disk 2 polishing tape 3a, 3b guide roll 4 backup roll 5 slit air nozzle

Claims (1)

[Claims] 1. A surface-polishing tape for a magnetic disk comprising a support and a polishing layer formed on the support, the polishing layer comprising abrasive particles and a binder.
A surface-polishing tape for a magnetic disk, comprising a zircoaluminate compound having the structure of [Chemical 1]