JPH05253850A - Abrasive tape for texturing surface of hard disk - Google Patents

Abstract

PURPOSE:To provide an abrasive tape which can form uniform irregularities on the surface when texturing the surface of a hard disk. CONSTITUTION:An abrasive tape which textures the surface of a hard disk, comprises an abrasive layer 2 formed in such a way that a mixture of abrasive grains and binder is applied to a base sheet 1 made of nonwoven cloth. In this case, since the nonwoven cloth acting as the base sheet is elastic, and allows to abrasion chips to remain, it is possible to form uniform irregularities (texturing) on the surface of a hard disk.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an abrasive tape for texturing the surface of a hard disk.

[0002]

2. Description of the Related Art Hard disks are used as magnetic storage media in computers and the like. The surface of this hard disk is plated with nickel-phosphorus, but the surface of the hard disk is textured in order to increase the density of magnetization.

For this texturing, an abrasive material (for example, aluminum oxide, zirconium oxide, etc.) is formed on a PET film (12 to 75 μm) which is a base material sheet in the past.
A polishing tape prepared by coating a mixture of a diamond (or the like) and a binder so as to have a thickness of 3 to 30 μm as a polishing layer has been used.

[0004]

However, in such a conventional texturing process using a polishing tape, the surface of the hard disk cannot be made uneven as shown in FIG. 3, resulting in uneven projections. .. Such unevenness hinders the advancement of the magnetization density. The lack of elasticity of the base sheet is considered as a cause of such unevenness of the unevenness. That is, if the base material sheet is not elastic, the abrasive having a large grain size deeply digs into the surface of the hard disk and creates unevenness more than desired.

Another cause is considered to be that polishing debris due to polishing remains on the hard disk, and the polishing debris makes the surface of the hard disk uneven.

Therefore, an object of the present invention is to provide a polishing tape capable of forming uniform unevenness on the surface of a hard disk when the surface of the hard disk is textured.

Still another object of the present invention is to provide a polishing tape capable of discharging polishing debris without leaving the polishing debris on the hard disk.

[0008]

A polishing tape for texture-processing the surface of a hard disk according to the present invention comprises a base material sheet made of a non-woven fabric, coated with a mixture of abrasive particles and a binder to form a polishing layer. It consists of The thickness of the polishing layer is preferably in the range of 1 μm to 10 μm, and the thickness of the substrate sheet is preferably in the range of 50 μm to 500 μm.

Here, the non-woven fabric may be a non-woven fabric composed of long fibers such as rayon, polyester, pulp, hemp, or a mixed paper of rayon and pulp. Further, a groove for discharging polishing waste may be provided on the polishing tape.

[0010]

The nonwoven fabric, which is the base sheet of the present invention, is elastic and has a thin polishing layer, so that even if relatively large abrasive particles are present on the abrasive tape, the abrasive particles when the abrasive tape is pressed against the hard disk are large. Penetrates into the base sheet, not into the hard disk. Therefore, even if there are some differences in the size of the abrasive particles, uniform unevenness is formed on the surface of the hard disk.

Further, the polishing waste is carried along with the polishing tape without remaining on the hard disk. When a groove for discharging the scraps is formed on the polishing tape, the scraps are discharged through the groove.

[0012]

EXAMPLE As shown in FIG. 1, a polishing tape for texturing a hard disk of the present invention is a nonwoven fabric 1
The polishing layer 2 is formed on the above. The nonwoven fabric of the base material sheet 1 is preferably a nonwoven fabric of rayon long fibers. However,
The base sheet 1 is not limited to this non-woven fabric, but may be polyester, urethane foam, paper, linen, or mixed paper (for example, mixed paper of rayon and pulp). The thickness of the base sheet 1 is preferably 50 to 500 μm. If it is too thin, it will lack elasticity.

The polishing layer 2 is formed by applying a kneaded material of abrasive particles and a binder onto the base sheet 1.
The abrasive particles are preferably aluminum oxide (Al ₂ O ₃ ) and chromium oxide (Cr) having an average particle size of 1 to 10 μm.
₂ O ₃ ), silicon carbide (SiC), iron oxide (Fe
₂ O ₃ ) etc. can be used.

The binder is preferably prepared by dissolving a saturated polyester resin in a mixed solvent of toluene, xylene, ethyl acetate and methyl ethyl ketone, and further adding an isocyanate compound curing agent.

The viscosity of the mixture of the abrasive particles and the binder adhesive when applied is 100 to 600 cp. When the kneaded material is applied to the base material sheet 1, the polishing layer 2 has a thickness of 1 to 10 μm.
m is performed.

The coating method may be so-called solid coating (see, for example, Japanese Examined Patent Publication No. 53-44714), but polishing scraps can be easily discharged from the polishing tape and effectively textured. It is desirable to form straight grooves forming an angle of 20 to 70 degrees on the surface of the layer at equal intervals (see FIG. 2). As the method for forming the grooves, a method of combing the surface of the polishing layer at regular intervals with a comb (US Pat. No. 2,755,607) and a direction of printing a polishing layer having various patterns on a base sheet (US Pat. 14
No. 2,334) or a substrate sheet whose surface is embossed, and the kneaded material is applied to form irregularities on the polishing layer by the surface tension of the kneaded material during drying (Japanese Patent Laid-Open No. 1-17).
1771).

Example 1 After heating 1 kg of aluminum oxide (average particle size 3 μm) at 100 ° C. for 1 hour, 1150 g of saturated polyester resin was mixed and stirred in a mixed solvent of toluene, xylene, ethyl acetate and methyl ethyl ketone (50
0 cp) and 75 g of an isocyanate-based curing agent were added, and the mixture was filtered with a wire mesh filter. This mixture was applied to a non-woven fabric of rayon material (long fibers) having a thickness of 90 μm to a uniform thickness of 3 μm and dried by a dryer.

[Example 2] A substrate sheet having a thickness of 200
The same polishing tape as in Example 1 except that a non-woven fabric of rayon material of μm was used.

[Example 3] A substrate sheet having a thickness of 860
The same polishing tape as in Example 1 except that a mixed paper of rayon and pulp of μm was used.

[Comparative] A conventional polishing tape prepared by coating a PET layer having a thickness of 25 μm with a polishing layer containing polishing particles of aluminum oxide having an average particle diameter of 2 μm for 3 μm was used for comparison.

A 3.5 "hard disk was textured using the above four types of tapes, and the disk roughness was measured.

The texture processing was carried out under the following conditions using a polishing machine manufactured by the company. Texture processing conditions Polishing time 20 seconds Tape feed 50 cm / min Spindle rotation 400 RPM Rubber hardness 40 degrees Oscillation rotation 160 RPM
Width ± 1mm Pressure 2.2kg

For the measurement of the disc roughness after polishing, eight points were measured using a contact-type roughness measuring instrument (P-1) manufactured by Tencor under the following conditions, and the average thereof was obtained. Measurement condition Diamond tip with a tip of 0.2μm R Measuring length 0.5mm
Measurement speed 20 μm / sec Cutoff 80 μm Needle load 5 mg Measurement position R = 23
mm

The results of the above measurements are shown in the table below. Here, Ra indicates the center line average roughness (Å), Rp indicates the center line mountain height (Å), and the ratio thereof indicates the protrusion rate. Therefore, it is shown that the smaller the protrusion rate, the more uniform the texture processing, that is, the more uniform the surface of the hard disk could be. As is clear from this table, the polishing tape of the present invention improved the protrusion ratio by 40% or more as compared with the conventional tape.

Table Tape Ra Rp Rp / Ra (protrusion ratio) Example 1 59 186 3.2 Example 2 68 213 3.1 Example 3 60 210 3.5 3.5 Conventional tape 64 325 5.1

FIG. 4 shows the state of protrusions on the surface of a hard disk that was textured with the polishing tape of the present invention. As is clear from comparison between FIG. 4 and FIG. 3, the polishing tape of the present invention remarkably improved the uniformity of the unevenness due to the texturing.

[0027]

When the surface of a hard disk is textured using the polishing tape of the present invention, it is possible to form uniform unevenness on the surface of the hard disk.

Furthermore, the polishing scraps generated by polishing can be discharged without remaining on the hard disk.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an abrasive tape for texturing the surface of a hard disk of the present invention.

FIG. 2 shows the polishing tape of the present invention having linear grooves formed on the surface of the polishing layer.

FIG. 3 shows the state of protrusions on the surface of a hard disk textured by a conventional polishing tape.

FIG. 4 shows the state of protrusions on the surface of a hard disk that has been texture-processed with the polishing tape of the present invention.

[Explanation of symbols]

 1 Base Material Sheet 2 Polishing Layer 3 Groove

Claims (5)

[Claims] 1. A polishing tape for texturing the surface of a hard disk, comprising a substrate sheet made of a non-woven fabric, and a mixture of abrasive particles and a binder applied on the substrate sheet to form a polishing layer. 2. The polishing tape according to claim 1, wherein the polishing layer has a thickness of 1 μm to 10 μm.
Polishing tape. 3. The polishing tape according to claim 1, wherein the thickness of the base sheet is in the range of 50 μm to 500 μm. 4. The polishing tape according to claim 1, wherein the nonwoven fabric is a nonwoven fabric made of rayon, polyester, pulp or hemp filaments. 5. The polishing tape according to claim 1, wherein a groove for discharging polishing waste is formed on a surface of the polishing tape.