JPS6294271A - Abrasive tape - Google Patents

Abstract

PURPOSE:To improve the abrasive performance for smoothening a finishing face, by containing in a covering layer an abradant comprising non-magnetic powder of high hardness. CONSTITUTION:An abrasive material, comprising non-magnetic powder whose hardness is more than Morse hardness 8 and average particle size is from 0.01mum and more than 0.1mum and less than, and binder is kneaded to obtain a material (coating layer) 2, which is adhesively applied to a flexible non- magnetic supporting member 1. Thus, due to the hardness more than Morse hardness 8, the abrasive performance is improved by eliminating flaws on the surface of a magnetic head, which is formed when a rough grinding is performed, so that RF output high enough for video or high grade audio use can be obtained. And, as the average particle size is set from 0.01mum and more than to 0.1mum and less than, the time required for smoothening the head face can be shortened with excellent smootheness on the finishing face.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a polishing tape used for precision polishing of magnetic heads of magnetic recording and reproducing devices, and particularly for final finishing of magnetic heads for video or high-end audio. This invention relates to the polishing tape used.

(Prior Art) When polishing a magnetic head using a polishing tape, first rough cutting is performed using a rough polishing tape, and then finishing is performed using a finishing polishing tape.

Tapes for finishing polishing include magnetic,
It is known that a head cleaning tape has been repurposed. This tape usually uses abrasive particles having an average particle diameter of 0.3 μm or more as an abrasive, and the coating 1 on the support is calendered to have a surface roughness (Ra) of 0.
．． It is set to 0.04 to 0.10 μm.

However, magnetic heads particularly for video or high-end audio use are required to have high characteristics.

When the above-mentioned tape is used to polish such a magnetic head, the particle size of the abrasive particles is too large and the hardness is too small, resulting in insufficient polishing of the head surface, making it difficult to obtain high characteristics. there were.

That is, the magnetic head is moved frJ by the above-mentioned tape.
Even after polishing, scratches left during rough cutting remained, making it difficult to obtain sufficient high-frequency characteristics as a magnetic head for video or high-end audio. In addition, it takes time to finish the head surface to a smooth finish, and the surface properties of the polished head surface are insufficient for use as a magnetic head for the above-mentioned applications.

(Object of the Invention) The present invention has been made in view of the above circumstances, and it is possible to polish the magnetic head surface in a short time so that the surface of the magnetic head has sufficient characteristics for use in video or high-end audio. The object of the present invention is to provide an abrasive tape that can be obtained.

(Structure of the Invention) The abrasive tape of the present invention comprises an abrasive made of a non-magnetic powder having a high hardness of 8 or more on the Mohs scale and an extremely small average particle size of less than 0.01 μm, and a binder (
It is characterized in that it is kneaded with a binder) and coated on a flexible non-magnetic support.

Here, the abrasive tape is not limited to what is called a tape-shaped polishing tape, and broadly includes disc-shaped or sheet-shaped polishing tapes.

(Effects of the Invention) According to the abrasive tape of the present invention, the magnetic head is abrasive using non-magnetic powder with high hardness, and the abrasive tape has a higher abrasive ability than the conventional one which uses abrasive particles of small hardness. As a result, polishing can be completed in a short time. In addition, since the non-magnetic powder is extremely fine, it is possible to form a finished surface with better smoothness than conventional methods that use abrasive particles with large particle diameters. A magnetic head polished by Cheap 4P can obtain sufficient characteristics as a magnetic head for video or high-end audio.

(Embodiment) Embodiments of the present invention will be described in detail below.

As shown in the drawings, the polishing tape according to the embodiment of the present invention is composed of a flexible non-magnetic support 1 and a coating 2 formed on the support 1. The coating layer 2 is formed by combining an abrasive and a binder. In addition, this abrasive is Cr z 03, A
It consists only of hard abrasive particles 4 such as 9Jz 03 and Si C with a Mohs hardness of 8 or more, and the average particle size is 0.
Extremely fine particles with a diameter of 0.01 μm or more and less than 0.1 μm are used. Furthermore, the surface roughness (Ra) of the coating layer 2 is set to 0.4 or less under the condition of a cutoff of 0.8, making it possible to perform super-finish polishing of a video magnetic head.

When polishing the tape sliding surface of the magnetic head 3, the polishing tape is run at a constant speed from one side of the reel (not shown) placed at two positions sandwiching the magnetic head 3 to the other. The coating layer 2 is slid on the head 3. At this time, the hard and fine abrasive particles 4 protruding from the surface of the coating layer 2 polish the tape 1 sliding surface of the magnetic head 3 smoothly.

The binder for bonding the polishing particles 4 to the support 1 is vinyl chloride-nylidene chloride copolymer, vinyl chloride-vinyl acetate-vinyl alcohol copolymer, vinyl chloride-vinyl acetate-maleic acid copolymer, etc. Polymers, vinyl chloride-vinyl propionate-maleic acid copolymers, di-1-cellulose, epoxy resins, isocyanate resins, polyamides, polyamines, etc. are preferably used.

By the way, as described above, the abrasive tape of the present invention uses hard and fine non-magnetic powder as the abrasive particles 4. That is, the average particle size is 0.01 μm or more with a fil' degree of Mohs hardness of 8 or more. nmii! I am using one from S. By setting the Mohs hardness to 8 or higher, the grinding ability is improved, and the scratches on the head surface caused during rough cutting are removed, and the RF specific output is high enough for video or high-end audio use. By setting the average particle size to 0.01 μm or more and less than 0.1 μm, the time required to smooth the head surface can be shortened, and at the same time, the polished head surface can be smoothed. This is to ensure that the surface properties are sufficient for use as a magnetic head for video or high-end audio.

In addition, in order to further enhance the above-mentioned effect, the average particle size of the abrasive particles 4 may be set to 0.01 μm to 0.03 μm. It is desirable to determine the above average particle size in consideration of the balance with the length of the minor axis.

Further, as the non-magnetic support 1 mentioned above, for example, polyethylene prephthalate (PET) or polyethylene naphthalate is used.

Furthermore, the thickness of the coating layer 2 depends on the shape of the magnetic head 3.

Although it depends on the material, if the thickness is too thick, the contact between the magnetic head 3 and the polishing tape will be poor, so it is preferably 50 μm or less.

Next, an example will be given and a detailed description will be given.

EXAMPLE A polishing tape 1 was prepared by coating a mixture having the following coating composition on a polyethylene terephthalate (PET) support having a thickness of 25 μm and a width of 1 part of 2 inches. In the following description, all parts indicate parts by weight.

Coating liquid composition・α-AQ, z 03...
... 95 parts (average particle size 0.2 μm, Mohs hardness 9)
・Vinyl chloride-vinylidene chloride copolymer... 15 parts ・Epoxy resin ・・・・・・
10 parts・Isocyanate resin・・・・・
・2 parts・butyl acetate ・・・・
・・250 parts・Methyl ethyl ketone ・・
...100 parts The surface roughness (Ra) of the coating layer of the 11Il polishing tape 1 is 0.09 μm. No calendaring was applied.

Comparative Example 1 As a comparative example to the above example, a polishing tape 2 was prepared by applying a liquid mixture having the following coating composition onto a support substantially similar to that of the above example. This comparative example is based on Japanese Patent Application Laid-Open No. 55-1177.
This is similar to Example 1 disclosed in Publication No. 30@.

Coating liquid composition/Cobalt-containing acicular iron oxide magnetic powder 7
0 parts/granular alpha iron oxide powder...
15 parts (average particle size 0.5 μm) ・5IC (average particle size 1.0 μm) ・・・・・・
10 parts Vinyl chloride-vinyl propionate...2
5-part maleic acid copolymer (Solon QA-431)
Methyl isobutyl ketone...100
Department/Dollor...1
00 parts Comparative Example 2 Polishing tape 3 was made in the same manner as in the example except that the size of the ω11 part (α-AizCh> in the example was changed to one having an average particle diameter of 0.5 μm).

Comparative Example 3 When coating the coating solution in the example on the support, the drying conditions were changed from those in the above example to improve the surface roughness (R) of the coating layer.
Polishing tape 4 was made in the same manner as in Example except that a) was changed to 0.9.

After polishing each video magnetic head using the polishing tapes of Examples and Comparative Examples 1, 2, and 3, each magnetic head is sequentially attached to a VTR to play back a standard magnetic tape on which signals have been recorded. At least I checked the RF specific output. The results are shown in the table below.

As is clear from the table above, when using the abrasive tapes of Comparative Examples 1.2.3, an RF specific output of at most +1 dB could not be obtained, whereas when using the abrasive tape of this example, A high RF ratio output of +5dB can be obtained.

[Brief explanation of drawings]

The drawing shows one example of the present invention during polishing of a magnetic head.
1 is an enlarged cross-sectional view of an abrasive tape made by 1...Nonmagnetic support (PET) 2...Coating 5 layer 3...Magnetic head 4.
... Abrasive particle (voluntary) procedure Nem Authorized Director General of the Patent Office January 962, 1986 Name of the invention Abrasive Tape 3 Relationship with the case of the person making the amendment Patent applicant Address 210 Nakanuma, Minamiashigara City, Kanagawa Prefecture Name
Fuji Photo Film Co., Ltd. 4, Agent: 5-2-1-6 Roppongi, Minato-ku, Tokyo Number of inventions increased by amendment: None 7: Subject of amendment: "Detailed description of the invention" column 8:
Contents of amendment 1) Page 3, line 20 of the specification

Claims (4)

[Claims] (1) An abrasive coating film made by kneading a binder with an abrasive agent made of a non-magnetic powder having a hardness of 8 or more on the Mohs scale and an average particle size of 0.01 μm or more and less than 0.1 μm is applied to a flexible non-magnetic film. An abrasive tape characterized by being coated on a magnetic support. (2) The polishing tape according to claim 1, wherein the non-magnetic powder has an average particle diameter of 0.01 μm or more and 0.03 μm or less. (3) Surface roughness (R
The polishing tape according to claim 1, wherein a) is 0.4 or less when the cutoff is 0.8 mm. (4) The polishing tape according to claim 1, wherein the non-magnetic powder consists of only an abrasive.