JPS59186131A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve the wear resistance and durability by sticking oleyl oleate to the surface of a magnetic layer contg. magnetic powder dispersed in a resin binder or by incorporating the compound in the layer. CONSTITUTION:Oleyl oleate is added to a magnetic coating material contg. magnetic powder dispersed in a resin binder by 5-50wt% of the amount of the resin component, and the resulting coating material is coated on a support to form a magnetic layer. An about 3wt% oleyl oleate soln. may be coated on the surface of a magnetic layer to stick 0.01-1.0g/m<2> oleyl oleate. Thus, a magnetic recording medium having superior lubricity, no stickiness, superior traveling performance and durability, e.g., a magnetic tape or a magnetic disk is obtd.

Description

[Detailed description of the invention] The present invention relates to magnetic recording media.

Magnetic recording media, such as magnetic tapes, magnetic disks, and magnetic sheets, are made by coating a non-magnetic support such as a polyester film with a magnetic paint in which magnetic powder is dispersed in a resin binder. Record by driving in contact.
It undergoes a large amount of wear due to the 4T regeneration process. For this reason, various measures have been taken in the past, such as improving the strength of the coating film, improving lubricity, and forming a protective coating. Among these, lubricants that are dispersed in the magnetic coating or applied to the surface have a high lubricating effect, and are therefore widely used. In particular, higher fatty acids, liquid paraffin, and the like are used as being relatively effective. However, as will be seen in the comparative examples described below, even these lubricants do not provide sufficient durability.

Therefore, an object of the present invention is to provide a magnetic recording medium in which the wear resistance of the magnetic layer is improved and the durability is improved.

In the present invention, oleyl oleate, which is an ester of unsaturated fatty acid and unsaturated higher alcohol, is dispersed in the magnetic layer.
Alternatively, the surface can be treated and its lubricating effect can significantly improve durability, which could not be expected with conventional lubricants.

In carrying out the present invention, oleyl oleate-1- is dissolved in a solvent such as n-hexane, and this solution is applied or sprayed onto a previously formed magnetic layer, or the magnetic layer is immersed in this solution. Alternatively, oleyl oleate may be cross-dispersed in the paint for forming the magnetic layer.

In the case of surface treatment, the amount of oleyl oleate is 0.
．． 01-1. It should be used within the range of OCJ/m2.

This amount is 0. The effect is not sufficient below O1g/m2.
If it exceeds 1,0(]/7n,2, it is undesirable as a sticky layer will form on the surface of the magnetic layer, making it easier for dust to adhere.Also, in the case of mixing and dispersing, the resin in the magnetic paint Oleyl oleate should be used in an amount of 5 to 50 wt% based on SWt.If this amount is less than 3% SWt, the effect will not be sufficient, and if it exceeds 50 wt%, the coating film strength will decrease due to the plasticizing effect of the lubricant. This results in a decrease in durability.

Hereinafter, examples of the present invention will be explained in more detail.
VAGII) polyurethane resin 14 (
Niraporan 2304 manufactured by Nippon Polyurethane Co., Ltd.) Polyisocyanate 6 (Coronet 1-L manufactured by Nippon Polyurethane Co., Ltd.) Carbon black
10 abrasive
5 mejile ethyl ken 1~n
150]~Luen
150 The above composition was sufficiently kneaded and dispersed in a ball mill to prepare a magnetic paint, which was applied onto a polyester base film to a dry thickness of 2.5 μm, dried, and then calendered. A magnetic layer was formed. A lubricant solution consisting of oleyl oleate 3 normal hexane 100 by weight was applied to the surface of the obtained magnetic layer at a concentration of 1.3 g/m2 to II ¥0.01 and dried to form a disc. I punched it out and created a magnetic disk.

Example 2 Overlapping part T-Fe203 magnetic powder 100 Vinyl chloride-vinyl acetate copolymer 22 (U.S. UCC
Polyurethane resin 14 (Nilaporan 2304, manufactured by Nippon Polyurethane Co., Ltd.) Polyisocyanate 6 (Coronate, manufactured by Nippon Polyurethane Co., Ltd.) Carbon black
10 abrasive
5 oleyl oleate-1 to 10
~7O-5 = Methyl Ezilken 1~N 150 The above composition was sufficiently mixed and dispersed in a ball mill to obtain a magnetic coating material, and this was applied onto a polyester base film to a dry thickness of 2.
．． After coating and drying the sea urchin, which is 571m long, Noko Render
This was processed into a magnetic layer, which was then punched out into a disk shape to create a magnetic disk.

Comparative Example 1 For comparison, a magnetic disk was prepared by punching out a magnetic disk having a magnetic layer without surface treatment with oleyl oleate in Example 1.

Comparative Example 2 A magnetic disk was produced according to Example 1, except that oleic acid was used instead of oleyl oleate.

Comparative Example 3 A magnetic disk was prepared according to the example using liquid paraffin instead of oleyl oleate.

The magnetic disks obtained in Examples and Comparative Examples were inserted into jackets and reproduced six times in a row at a head pressure of 150 y/cm2, and the time required for the output to reach 80% of the initial level was measured.

FIG. 1 shows the results of measurements made on the surface-treated magnetic disk of Example 1. The abscess on the surface of Oleyl Ole-1 was 0.01 g/m2, and the durability was about 400 hours. At 0.05 g/m2, the durability was 500 hours or more. Even at higher surface concentrations, the duration was 500 hours or more. Note that the measurement was discontinued after a little over 500 hours, so the actual durability is better than the case shown in Figure 1. On the other hand, the same figure also shows the stickiness of the magnetic disk surface.

As can be seen from the figure, it was found that stickiness increased when the surface concentration of A-rail oleay-1 was greater than 1.0 g/m2. In the figure, O indicates no stickiness, △ indicates slight stickiness, and × indicates much stickiness.

FIG. 2 shows the measurement results for the crosstalk dispersion type magnetic disk of Example 2. When the amount added to Oleyl Ole-1 was 5 wt%, the durability was about 350 hours, and the durability was 10 W [%
That's over 500 hours. When the amount added exceeds about 40%, the durability begins to decrease, and at about 50 wt%, it decreases to about 400 hours.

In addition, in Example 2, the magnetic powder to resin ratio was 2.4 to 1.
(weight ratio), but when a similar experiment was conducted with this ratio changed to 3.5:1, the same 4-piece result as in Example 2 was obtained.

On the other hand, the durability of Comparative Examples 1, 2, and 3 was measured for about 50 hours, about 200 hours, and about 150 hours, respectively.

From these results, it was revealed that the magnetic layer containing oleyl A-ray 1 to 1 of the present invention was extremely excellent in durability dimension 1. It will be apparent to those skilled in the art that many variations are possible within the scope of the invention. For example, other resins may be used as the binder resin, and not only γ-100203 but also γ-FC! 20a, metal magnetic powder, etc. can be used.

[Brief explanation of the drawing]

Figure 1 is a graph showing the relationship between the durability of the magnetic disk according to Example 1 and the surface concentration of oleyl oleate 1-1, and Figure 2 is a graph showing the relationship between the durability of the magnetic disk according to Example 1 and the amount of oleyl oleate added. It is a graph showing the relationship between =9-

Claims (1)

[Claims] 1. A magnetic recording medium having a magnetic layer dispersed in a magnetic powder resin binder, characterized in that the magnetic layer retains oleyl oleate-1- at least in its surface portion. recoding media. 2. The magnetic recording medium according to item 1 above, wherein oleyl oleate is attached to the surface of the magnetic layer. 3. The magnetic recording medium according to item 1 above, wherein oleyl oleate is dispersed inside the magnetic layer. 4. Oleyl oleate has a surface concentration of 0.01 to 1, Og
2. The magnetic recording medium according to item 2 above, which has a magnetic field index of /7712. 5. Oleyl oleate is 5 to 50 W [based on the resin content]
%.