JPH02266926A - Polishing tape - Google Patents

Abstract

PURPOSE:To eliminate the adhesion of dust due to static elasticity and to polish a magnetic head without damaging the slide surface of a tape by providing a polishing layer composed of a membrane formed by a PVD method specific in Vickers hardness and surface electric resistivity on a plastic substrate. CONSTITUTION:A polishing layer composed of a membrane formed by a PVD method having Vickers hardness of 500 or more and surface electric resistivity of 10<10> ohm or less is provided on a plastic substrate. This polishing tape is excellent in polishing action because of its high hardness and suppressed in the generation and accumulation of static electricity even when a magnetic head is slid for a long time because surface electric resistivity is 10<10> ohm or less and, since the adhesion of dust in air or polishing refuse is not generated, the slide surface of the tape is not damaged and the magnetic head can be well polished. Since no binder is contained in the polishing layer, the adhered substance from the polishing layer is not adhered to a surface to be polished during a polishing process and the capacity of the magnetic head is not deteriorated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a polishing tape used for polishing a magnetic head of a magnetic recording/reproducing device.

(Prior Art and its Problems) In order to perform good recording and reproduction, a magnetic head for video or high-end audio needs to have an appropriate curvature and a smooth tape sliding surface. For this reason, generally when manufacturing a magnetic head, a polishing tape is used to give the head an appropriate curvature, and a step is also provided to smoothen the tape sliding surface.

Conventionally, such abrasive tapes are made of Cr=o3, Few Os on a plastic substrate.

Abrasive particles such as AelOs and SIC, and binders,
A product coated with an abrasive coating containing lubricant, etc. is used. (Unexamined Japanese Patent Publication No. 62-224579, Unexamined Japanese Patent Publication No. 62-224579,
(Japanese Patent Publication No. 2-224581, Japanese Unexamined Patent Publication No. 62-176771) However, with such abrasive tapes, static electricity is generated by sliding the magnetic head for a long time, and ■dust in the air ■polishing debris etc. There is a problem in that it adheres to the tape and gets between the polishing tape and the magnetic head, eventually damaging the tape sliding surface of the magnetic head. This problem was particularly serious under low humidity conditions.

Also, with the tape on the grind like this! +? ! ? When the surface roughness is reduced for polishing purposes, there is a problem in that the binder adheres to the surface of the magnetic head, resulting in a decrease in output.

(Problems to be Solved by the Invention) The present invention has been made to solve the above-mentioned problems, and is capable of polishing a magnetic head without the adhesion of dust due to static electricity and without damaging the tape sliding surface of the magnetic head. The purpose of the present invention is to provide a polishing tape for precision polishing that can be used for precision polishing.

(Means for Solving the Problems) The object of the present invention is to coat a plastic substrate with a P layer having a Vickers hardness of 500 or more and a surface electrical resistivity of io'' ohms or less.
This is achieved by using a polishing tape provided with a polishing layer made of a thin film made by the VD method.

In particular, the median surface roughness Ra of the polished VIN surface is 0.03 to 0.3μ when the cutoff length is O18.
It is effective to use an abrasive tape having a diameter of m.

The polishing tape of the present invention has a high Vickers hardness of 500 or more, so it has excellent polishing action, and its electrical resistivity is less than IQI @ ohm, so it will not generate static electricity even when a magnetic head is slid for a long time. Accumulation is suppressed and there is no adhesion of dust or polishing debris in the air, so there is no damage to the polished surface.
Good polishing of the magnetic head is possible. Furthermore, since the polishing tape of the present invention does not contain a binder in the polishing layer unlike conventional polishing tapes, deposits from the polishing arm do not adhere to the polishing surface during the polishing process, so that the magnetic head In addition, since the surface roughness of the surface of the polishing layer can be made relatively small, the smoothness of the polishing surface of the magnetic head can be improved.
In particular, the median surface roughness Ra is 0.03 to 0.3 μm (
It is desirable that the cutoff length be 0.8 mm).

The polishing layer of the polishing tape of the present invention is formed by physical vapor deposition (PVD).
It is a thin film that is formed on a plastic substrate by a method (method).

As the PVD method, a method such as a vacuum evaporation method, a reactive vacuum evaporation method, an ion blating method, an ion assisted evaporation method, a sputtering method, etc. can be selected.

However, since the polishing layer of the present invention is made of ilM having sufficient hardness, it is necessary to contain a considerable amount of highly hard ceramics in the polishing layer. Therefore, the following method is used for film formation.

For example, (1) titanium is vapor-deposited in oxygen or nitrogen-containing gas to obtain 11pH) II containing titanium oxide or titanium nitride.

(Reactive Vapor Deposition Method) (1) Aluminum is vapor-deposited in an RF plasma of a gas containing oxygen to obtain a polished thin film containing aluminum oxide.

(Ion Blating Method) ■While depositing iron, air gas is simultaneously ionized using an ion gun and sent to the film forming area to obtain a polished thin film containing iron oxynitride.

(Ion assisted method) The polishing layer is made of a thin film formed by the above-mentioned PVD method.
For example, the following compositions can be selected. However, what is important here is that by appropriately selecting the parameters of the PVD method, the composition can be controlled, and the properties such as the hardness and surface electrical resistivity of the thin film of the resulting polishing layer can be controlled. .

The composition of the polishing layer thin film formed by the PVD method is, for example, Cr, O, +Cr main components, Aj! x 03 +Af principal component, Fee 02 +Fe
Main components: TiNx+Ti, AIN+A1.5ilN.

+Si, BN soil component, SiC+Sl, TiOx+Ti,
BeO+Be5Styx%TiC+T1Cr5 C intention+
Cr, WC, diamond-like carbon main component, iron oxynitride, etc., especially Cr, O.

+Cr main component, 111.0. +AJ main component, TiNx
+Ti main component, SiC+Si main component, TiOx+Ti main component, and diamond-like carbon main component are preferable.

Further, the hardness of the polishing layer is a Vickers hardness of 500 or more, more preferably 1000 or more, and even more preferably 1500 or more. It is preferable that the Vickers hardness is higher because the polishing time can be shortened. Since the polishing layer is a thin film, a hardness tester for thin films is used to measure the Vickers hardness.The surface electrical resistivity of the polishing layer is 10'6 ohm or less.
More preferably 10 ohms or less, even more preferably 10
'0 surface electrical resistivity that is less than or equal to ohm is measured using a commercially available meter (
For example, it can be measured using Tokyo Denshi Co., Ltd.'s 5TACK TR-3). The measurement is performed by pressing two probes against a tape-shaped polishing tape and reading the resistance value.The environmental atmosphere at this time is a temperature of 10° C. to 30° C. and a relative humidity of 15% to 85%.

In order to keep the hardness and surface electrical resistivity of the polishing layer within the above ranges, for example, taking the main component of A1*Os+A1 as an example, A1 is deposited while 0.0. It is necessary to appropriately select the 0-fold partial pressure, A2 evaporation rate, 08 ionization rate, etc. at the time of gas introduction.

Do it in a similar way.

The plastic substrate of the abrasive tape of the present invention includes polyethylene terephthalate, polyimide, polyamide,
Polyethylene naphthalate, polyvinylidene, etc. can be used. The required thickness is between 5μm and 5μm in order to achieve both stiffness and flexibility required in the polishing process.
0um, more preferably 110A1~'30μm. In particular, since the polishing layer of the present invention is a thin film, the surface properties of the substrate used have a large effect on the final roughness of the polishing layer. Therefore, it is also important to control the surface roughness of the substrate. However, the median surface roughness Ra is 0.01-0.5 μm, preferably 0.03-0.3 In (cutoff length 0.05 μm).
8) is desirable.

If it is smaller than this range, the polishing ability when used as a polishing tape will be insufficient and the polishing time will be long.

On the other hand, if it is larger than this range, the sliding surface of the magnetic helide will be damaged, causing problems such as a decrease in output.

A polishing layer is provided on the plastic substrate directly or via an intermediate layer. The thickness of the polishing layer is 250 to 7,500, more preferably 500 to 7,500, in order to achieve both the durability required for the polishing layer and the flexibility required for the polishing tape. If it is smaller than this range, the durability of the polishing layer will be insufficient and the polishing layer may come off during polishing. On the other hand, if it is larger than this range, the polishing layer becomes too stiff and the polishing tape lacks flexibility, which causes problems in precision polishing of the magnetic head.

〔Effect of the invention〕

Visical hardness of 500 or more, surface electrical resistivity of 10"
By using a polishing tape in which a thin film of ohm or higher is formed as a polishing layer on a plastic substrate by PVD method, scratches on the polishing surface due to dust and deposits occur even after long-term polishing, and the performance of the magnetic head deteriorates. It is possible to perform polishing without such problems.

In particular, by controlling the surface roughness of the polishing layer, precision polishing that cannot be achieved with conventional polishing tapes is possible.

The novel effects of the present invention will be explained in more detail by the following Examples and Comparative Examples.

(Example 1) A polishing tape was prepared using a vapor deposition apparatus whose main parts are illustrated in FIG.

Nobu 100 set on the delivery shaft 2 in the vacuum chamber 1,
The substrate 10 is pulled out from a polyimide roll 3 having a thickness of 2 o#m% and a median surface roughness Ra of 0.1 d/m (measured with a stylus roughness meter at a cut-off length of 008-), and then placed on a cooling drum 4.
It was wound up along the winding shaft 5 at a winding speed of 3 d/min. The vacuum chamber 1 was evacuated from an exhaust port 6 connected to a vacuum pump until the degree of vacuum in the vacuum chamber 1 reached 1×10 −s Torr.

1001d/1001d/
Oxygen gas is introduced at an introduction speed of 500 V, and the acceleration voltage is 500 V.
An ion stream 9 was generated with an ion current of 50 mA and directed onto the plastic substrate 10 placed along the cooling drum 4. On the other hand, Al having a purity of 3N was placed in a vapor deposition container 11 as a vapor deposition substance 12, and a vapor flow 13 was directed onto the plastic substrate 10 on the cooling drum 4 by electron beam heating.

A region in which the ion flow 9 and the vapor flow 13 reach the plastic substrate 10 was determined by a mask 14 provided on the front surface of the cooling drum 4, and a thin film of aluminum oxide was formed in that region. .

After film formation, the original fabric roll 15 was scraped off by the former reporter scraping shaft 5
was slit into 1/2 inch width to obtain a polishing tape having aluminum oxide as a polishing layer.

The Vickers hardness of the polishing tape is 2100 Tokyo Electronics Co., Ltd.
The surface electrical resistivity measured with 5TACK TR-3 manufactured by Kogyo Co., Ltd. was 10 ohms.

(Example 2) A polishing tape was prepared under the same conditions as in Example 1 except that the ion current value applied to the Kauffman type ion gun 7 was changed to 100 mA. An abrasive tape with a Biwakaas hardness of 220 G and a surface electrical resistivity of 10'' ohm was obtained.

(Example 3) A polishing tape was prepared under the same conditions as in Example 1 except that the ion current value applied to the Kauffman type ion gun 7 was changed to 25 mA. A polishing tape having a Vickers hardness of 1700 and a surface electrical resistivity of 107 ohms was obtained.

(Example 4) A polishing tape was prepared under the same conditions as in Example 1 except that the ion current value applied to the Kauffman type ion gun 7 was changed to 10 mA. Vickers hardness is 1500. A polishing tape having a surface electrical resistivity of 10-ohm was obtained.

(Example 5) A polishing tape was prepared under the same conditions as in Example 1 except that the ion current value applied to the Kauffman type ion gun 7 was changed to 5 mA. A polishing tape having a Vickers hardness of 1300 and a surface electrical resistivity of 10' ohm was obtained.

(Example 6) From the gas inlet 8 to the Kauffman type ion gun 7,
Nitrogen gas was introduced at an introduction rate of 0 to 7 minutes, and ions were generated at an accelerating voltage of 5 oov and an ion current of 50 mA. A polishing tape having a titanium nitride thin film as a polishing layer was obtained under the same conditions. The polishing layer had a Vickers hardness of 1900 and a surface electrical resistivity of 101 ohms.

(Example 7) A polishing tape was produced under the same conditions as in Example 6 except that the ion current value applied to the Kauffman type ion gun 7 was changed to 100 mA. Visical hardness was 2050, and surface electrical resistivity was 10' ohm.

(Example 8) A polishing tape was prepared under the same conditions as in Example 6 except that the ion current value applied to the Kauffman type ion gun 7 was changed to 25 mA. The Vickers hardness was 1750 and the surface electrical resistivity was 10" ohms.

(Example 9) A polishing tape was prepared under the same conditions as in Example 6 except that the ion current value applied to the Kauffman type ion gun 7 was changed to 10 mA. The Vickers hardness was 1300 and the surface electrical resistivity was 10' ohm.

(Example 10) A polishing tape was prepared under the same conditions as in Example 6 except that the ion current value applied to the Kauffman type ion gun 7 was changed to 5 mA. The Vickers hardness was 1100 and the surface electrical resistivity was 104 ohms.

(Comparative example) Cobalt-containing acicular iron oxide magnetic powder 70 parts Granular alpha iron oxide powder 15 parts (average particle size 0.5μ
m) SiC (average particle size 1.0 μm) 10 parts Vinyl chloride-vinyl propionate-maleic acid copolymer (Sonyron QA-431) 25 parts Methyl isobutyl ketone 100 parts Doluol 100 parts or more of the composition was ground in a sand grinder. A uniform coating solution was obtained by dispersing for about 1 hour. This coating solution was applied onto a polyethylene terephthalate substrate having a thickness of 20 μm to a dry film thickness of 5 μm, and after drying, it was slit into 1/2 inch width to obtain an abrasive tape.

The abrasive tapes obtained in the above Examples and Comparative Examples were evaluated for their abrasive ability and susceptibility to head scratches.

The ease of head scratches is determined by the number of scratches larger than 2 microns (0.5 mm wide ) in the interval.

Also, Ken 1m! Regarding power, 23℃70%RH.

This is the amount of head polishing when the head is polished for 10 seconds in an atmosphere.

Grinding power Ease of head scratching Example 1 12. un 2 pieces 2 7μm
None 3 7#m None 4 6μm None 5 3μm None 6 15xm 1 piece 7 11J1m None 8 10um None 9 6μm None 10 5#m None Comparative example 6#m 20 The abrasive tapes of the present invention in Examples 1 to 10 were , Kenma
It was found that the i-force was large and that it was superior to the conventional abrasive tape of the comparative example, especially in terms of head scratches caused by abrasion.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the main parts of a vapor deposition apparatus for producing the polishing tape of the present invention. 1... Vacuum chamber 4... Cooling drum 7... Kaufmann type ion system 9...-
・Ion flow 1G...Plastic base 13...
・・・ Steam flow

Claims (1)

[Scope of Claims] 1) An abrasive tape having an abrasive layer made of a thin film made by the PVD method and having a Vickers hardness of 500 or more and a surface electrical resistivity of 10^1^■ ohm or less on a plastic substrate. 2) The median surface roughness Ra of the surface of the polishing layer is 0.03 to 0.3μ when the cutoff length is 0.8mm.
The abrasive tape according to claim 1, which is m.