JPS58164022A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To enhance the wear resitance of a magnetic layer by adding oleic acid and a silicone lubricant to the layer. CONSTITUTION:To a magnetic layer are added oleic acid and a silicone lubricant such as dimethylsilicone oil, methylphenylsilicon oil or fluorosilicone oil. The blending ratio between the oleic acid and the lubricant is 9:1-5:5 by weight, and the total amount of them is 0.1-20wt% of the amount of magnetic powder in the magnetic layer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording medium, and an object thereof is to provide a magnetic recording medium with excellent durability.

-a, a magnetic recording medium is made by applying a magnetic paint consisting of magnetic powder, binder resin, organic solvent, and other necessary components onto a substrate such as a polyester film, and the magnetic head, pad, etc. are used during recording and reproduction. Because of the intense sliding contact, the magnetic layer is likely to be abraded, so a magnetic layer that is less abrasive and has excellent durability is required.

For this reason, various lubricants are mixed into the magnetic layer as a way to improve the wear resistance of the magnetic layer.
For example, a magnetic layer containing a silicone lubricant such as silicone oil has been proposed.

However, although the abrasion resistance is certainly improved by incorporating this silicone-based lubricant, it is not sufficient.In particular, when this silicone-based lubricant is used in the magnetic layer of a magnetic disk, etc., it has problems such as pad staining. be.

The inventors conducted various studies in view of the above circumstances and found that the wear resistance of the magnetic layer can be sufficiently improved by incorporating oleic acid into the magnetic layer in combination with a silicone lubricant. , this invention was made.

The olein used in this invention has a carbon number of 1 or more.
It is an oily unsaturated fatty acid of No. 8 and has excellent lubricating ability, and when used together with a silicone lubricant, it is compatible and the lubricating functions of both act synergistically, further improving the wear resistance of the magnetic layer. In addition, by incorporating these into the magnetic layer of the magnetic disk due to the synergistic effect of the two, the disadvantages of containing silicone lubricant alone are eliminated, and the pad does not get dirty. Although the pad tends to wear out during use, this pad wear is alleviated and the wear resistance is improved.

Further, as the silicone lubricant used in combination, various modified silicone compounds such as dimethyl silicone oil, methylphenyl silicone oil, fluorosilicone oil, etc. are preferably used. This type of silicone lubricant has excellent lubrication ability, and when contained in the magnetic layer, reduces the wear coefficient of the magnetic layer and improves the wear resistance of the magnetic layer.

The blending ratio of oleic acid to such a silicone lubricant is preferably within the range of 9:1 to 5:5 by weight (silicone lubricant to oleic acid), and the blending ratio of oleic acid is preferably within the range of 9:1 to 5:5. If the amount is too small, the wear resistance of the magnetic layer will not be sufficiently improved, and if it is too large, the pad may be worn out when used as the magnetic layer of a magnetic disk.

Also, the amount of silicone lubricant and oleic acid mixed in such a proportion is 0.1 to 20 times the magnetic powder in total! ? It is preferable to keep it within 1%,
If it is too small, the desired effect cannot be obtained, and if it is too large, it may bleed out onto the surface of the magnetic layer, contaminating the magnetic head, and lowering the output.

To incorporate oleic acid and a silicone-based lubricant into the magnetic layer, dissolve them in a suitable solvent such as normal hekylin, and apply or spray the solution obtained by dissolving onto the preformed magnetic layer. Alternatively, conversely, the magnetic layer may be immersed in the above solution, or it may be incorporated by kneading these together with a magnetic powder and a binder resin to form a magnetic layer.

Next, embodiments of the invention will be described.

Example I Co-containing -Fe203 magnetic powder 270-mli parts VAGH (manufactured by U.C.C., USA, salt 80 vinylide-vinyl acetate-vinyl alcohol copolymer)
)N 1432J (manufactured by Zeon Corporation,
15 Acrylonitrinobi-butadiene copolymer) Coronate Nippon Polyurethane 10 parts by weight Trifunctional low molecular weight isocyanate compound manufactured by N Kogyo Co., Ltd.) T-IS-500 (manufactured by Asahi Carbon Co., Ltd., 34
〃Carbon black) α-Fe203 powder 11 〃Methyl isobutyl ketone 420 〃Toluene
420 This composition was mixed and dispersed in a ball mill to prepare a magnetic paint.
A 5μ polyester film was coated on both sides to a dry thickness of 3μ and dried for 12 hours to form a magnetic layer. Next, this was immersed for a short time in an impregnating solution consisting of 40 parts by weight of oleic acid, 10 parts by weight of dimethyl silicone oil, and xooofj parts of n-hexane, dried, and then punched out into a disc shape to produce a magnetic disk.

Example 2 In the composition of the magnetic paint in Example 1, the amount of VAGH used was changed from 80 parts by weight to 40 parts by weight, and the amount of Coronate L used was changed from 10 parts by weight to 20 parts by weight, and N 1432.7 omitted, new bandex T-
5201 (manufactured by Dainippon Ink & Chemicals Co., Ltd., urethane elastomer) Total 40? A magnetic disk was produced in the same manner as in Example 1 except that fj parts were added.

Comparative Example 1 A magnetic disk was produced in the same manner as in Example 1 except that oleic acid was omitted from the composition of the impregnating solution in Example 1.

Comparative Example 2 A magnetic disk was produced in the same manner as in Example 1 except that dimethyl silicone oil was omitted from the composition of the impregnating solution in Example 1.

In order to examine the durability of the magnetic disks obtained in each example and each comparative example, each magnetic disk was inserted into a dirt prevention jacket, loaded into the recording/reproducing device a, and contacted with the L1 magnetic head at a pad pressure of 25 r/cJ. Circumferential speed 10 m
The playback output is 50% of the initial output while sliding at /sec.
The regular running time until K"l was measured.

The table below shows the results.

As is clear from the table above, both the magnetic disks obtained by the present invention (Examples 1 and 2) have a longer running time than the conventional magnetic disks (Comparative Examples 1 and 2). It can be seen that the magnetic recording medium obtained by this invention has excellent durability.

Claims (1)

[Claims] 1. A magnetic recording medium having a magnetic layer containing oleic acid and a silicone lubricant