JPS63173225A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve the lubricity and durability of the magnetic layer in a wide temp. range by forming the magnetic layer contg. oleic acid and ethyl stearate or ethyl oleate and 2-ethylhexyl laurate on a supporting body. CONSTITUTION:The magnetic layer contg. oleic acid and ethyl stearate or ethyl oleate and 2-ethylhexyl laurate is formed on a supporting body. The ethyl stearate or ethyl oleate jointly used with oleic acid is the ester of 2 C ethyl alcohol and 18 C stearic acid or oleic acid, and as stabilized lubricity in a wide temp. range. Meanwhile, the 2-ethylhexyl laurate is the ester of 8 C 2- etylhexyl alcohol and 12 C lauric acid, and has excellent lubricity especially under low-temp. conditions. As a result, the wear resistance and durability of the magnetic layer are improved in a wide temp. range.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to magnetic recording media used for high-density recording such as digital audio tapes, high-definition video tapes, and high-density floppy disks. The present invention relates to a magnetic recording medium with excellent durability.

Conventional technology In general, magnetic recording media are made by coating a magnetic paint consisting of magnetic powder, binder resin, organic solvent, and other necessary components on a substrate such as a polyester film. The magnetic layer is easily worn out due to intense contact with
High durability with less wear on the magnetic layer is desired. Efforts have been made by many people to improve the durability of magnetic recording media, and various lubricants have been mixed or applied to the magnetic layer. Liquid paraffin, higher fatty acids, higher fatty acid esters, etc. are used as such lubricants.

Problems to be Solved by the Invention Although the use of these lubricants improves the durability of magnetic recording media, there is a problem in that a medium with sufficient properties has not yet been realized.

The present invention is intended to solve these problems, and aims to provide a magnetic recording medium whose magnetic layer has good lubrication properties over a wide temperature range and has excellent durability.

Means for Solving the Problems The magnetic recording medium according to the present invention is one in which a magnetic layer containing oleic acid, ethyl stearate or ethyl oleate and 2-ethylhexyl laurate is formed on a support.

Function: This configuration provides stable lubrication properties and long durability over a wide temperature range. The oleic acid used in the present invention is an unsaturated fatty acid with 18 carbon atoms that is liquid at room temperature and has excellent lubrication ability, especially when the magnetic layer is in direct contact with the magnetic head. is fully exhibited, and the durability of the magnetic layer is improved. Furthermore, when used in combination with ethyl stearate-straddling ethyl oleate and 2-ethylhexyl laurate, the lubricating functions of these three act synergistically to further improve the lubrication properties and wear resistance of the magnetic layer.

Ethyl stearate or ethyl oleate, which is used in combination with oleic acid in this invention, is an ester obtained from ethyl alcohol with 2 carbon atoms and stearic acid or oleic acid with 18 carbon atoms, and has a stable lubricating function over a wide temperature range. has.

On the other hand, 2-ethylhexyl laurate has 8 carbon atoms.
An ester of ethylhexyl alcohol and lauric acid with 12 carbon atoms.It has excellent lubricating effect especially at low temperatures, and when used together with oleic acid, these act synergistically to improve the wear resistance of the magnetic layer. This further improves the lubrication properties and wear resistance over a wide temperature range.

The blending ratio of all oleic acid esters (ethyl stearate or the total amount of ethyl oleate and 2-ethylhexyl laurate) is preferably within the range of 1:2 to 1:8 by weight, and these lubricants used together If the blending ratio of any of the agents is too small, the abrasion resistance of the magnetic layer will not be sufficiently improved. In particular, if the blending ratio of the ester amount is too small, the abrasion resistance at high temperatures will not be improved.

Furthermore, if the blending ratio of oleic acid is too high, the coefficient of friction with the pad will increase, making running unstable. If the blending ratio of ester is too high, it will bleed out onto the surface of the magnetic layer, staining the head, and reducing the output. The wear resistance of the pad is also reduced, which tends to cause problems with bending.

The total amount of oleic acid and ethylene stearate or ethyl oleate and 2-ethylhexyl laurate blended in such proportions should be within the range of 5 to 16 weight percent based on the magnetic powder. is preferable; if it is too small, the desired effect will not be obtained, and if it is too large, it will bleed out onto the surface of the magnetic layer, staining the magnetic head, and causing a decrease in output.

In order to incorporate oleic acid and ethylene stearate or ethyl slate or 2-ethylhexyl laurate into the magnetic layer, dissolve them in a suitable solvent such as n-hexane, and apply the resulting solution to the pre-formed magnetic layer. This can be done by coating or spraying on the solution, or by immersing the magnetic layer in the solution, or by kneading these together with magnetic powder and binder resin to form a magnetic layer.

Example Examples of the present invention will be described below.

Example 1 Oleic acid 2 parts by weight Magnetic powder 250 parts by weight WAG) I (vinyl chloride-vinyl acetate-vinyl alcohol copolymer manufactured by UCC, USA) 82 parts by weight N-2304 (polyurethane manufactured by Nippon Polyurethane Industries)
18 parts by weight Coronet) L (polyisocyanate made by Nippon Polyurethane Industries) 7.6 parts by weight Granular alumina 12.6 parts by weight Carbon black 16 parts by weight Methyl ethyl ketone 600 parts by weight Toluene
600 parts by weight of this composition was mixed and dispersed in a ball mill to prepare a magnetic paint, and this magnetic paint was applied to both sides of a 75-micron thick polyester film to a dry thickness of 2 microns, and then dried. A magnetic layer was formed. Next, this was immersed for a short time in an impregnating solution having the composition ratio shown in Table 1 prepared separately, and after drying, it was punched out into a disk shape to produce a magnetic disk.

(Space below) Example 2 The ratio of oleic acid, ethyl oleate and 2-ethylhexyl laurate was 1:1:3.6 by weight, and the total weight of these was about 8% of the magnetic powder. A magnetic coating was prepared by kneading with magnetic powder and a binder resin, and a magnetic disk was produced in the same manner as in Example 1, except that immersion in an impregnating solution was omitted.

Comparative Example 1 In the blending composition of fatty acids and esters in Example 2, oleic acid was changed to lentin, ethyl oleate was changed to n-butyl stearate, and 2-ethylhexyl laurate was changed to oleyl adipate in equal amounts. A magnetic disk was produced in the same manner as in Example 2.

In order to examine the durability of the magnetic disks obtained in each Example and each Comparative Example at room temperature and high/low temperature, each magnetic disk was inserted into a dirt-prevention jacket and loaded into a recording/reproducing device at 0°C to 60°C. Under each condition, the running time until the reproduction output reached 80% of the initial output was measured while the magnetic head was brought into contact with the pad pressure of 2rsf/aA. Table 2 shows the results. Example 3 The magnetic layer formed in Example 1 was immersed for a short time in an impregnating solution having the composition ratio shown in Table 3 prepared separately, and after drying, I punched it out into a plate shape to make a magnetic disk.

Example 4 Magnetic powder and A magnetic disk was made in the same manner as in Example 1, except that a magnetic paint was prepared by kneading with a binder resin, and immersion in an impregnating solution was omitted.

Comparative Example 2 In the blending composition of fatty acids and esters in Example 4, oleic acid was changed to lecithin, ethyl stearate was changed to n-butyl stearate, and 2-ethylhexyl laure if oleyl adipate were changed in equal amounts. A magnetic disk was produced in the same manner as in Example 4.

Similarly, for the magnetic disks obtained in the above Examples and Comparative Examples, each magnetic disk was inserted into a dirt prevention jacket and loaded into a recording/reproducing device, and the magnetic head was padded under various conditions of 0°C to 60°C. The running time until the reproduction output reached 80% of the initial output was measured while contacting at a pressure of 26 da/d.Table 4 shows the results.

(Hereinafter, blank space) As is clear from this, the magnetic disks obtained by the present invention all have a longer running time at 0° C. to 50° C. compared to the magnetic disks obtained in the comparative example.

Effects of the Invention As described above, according to the present invention, it is possible to obtain the effect that the magnetic layer has good wear resistance and excellent durability in a wide temperature range.

Claims (1)

[Claims] 1. A magnetic recording medium comprising a magnetic layer comprising oleic acid and ethyl stearate or ethyl oleate and 2-ethylhexyl laurate formed on a support.