JPS6016008B2 - Manufacturing method of magnetic disk - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a coating film constituting a magnetic layer in a magnetic disk as a recording medium of a magnetic disk device.

In recent years, magnetic disk drives have become more densely packed with contacts.
The start-stop method is adopted to reduce the flying gap between the magnetic head and the magnetic disk, so the magnetic disk coating on the media is wear-resistant without damaging the monolithic type magnetic head. There is a demand for high strength materials with excellent head crush resistance and head flying properties.

Therefore, if hard alumina, silica, etc. are added to the paint to form a coating film, the strength of the coating improves, but the magnetic head is destroyed, resulting in a decrease in output and poor recording characteristics. In view of these points, it is an object of the present invention to provide an improved method for manufacturing a magnetic disk so as to form a strong coating without destroying the magnetic head. Focusing on the fact that suitable strength can be obtained, we put a thermosetting resin together with a magnetic oxide in the paint to form a coating film, and then added a long film that has excellent heat absorption properties to the resin. It is baked and hardened in a short period of time using an infrared heater at a certain wavelength with almost no oxidation.

The present invention will be explained in detail below with reference to the drawings. A thermosetting resin such as acrylic or epoxy is put in a paint together with a magnetic oxide such as gamma iron oxide (yFe203), and this is applied to an aluminum disc substrate. A magnetic layer is formed by applying a thin and uniform coating onto the magnetic layer using spin coating or the like.

Thereafter, the coating film is subjected to an orientation treatment, and then this coated coating is heated at about 2000 C for about 2 minutes using an infrared heater with a long wavelength of 50 peaks or more to perform a heat treatment. Then, since the long wavelength infrared rays are very well absorbed by the thermosetting resin, the resin hardens in about 2 minutes, with almost no oxidation, and a magnetic disk is manufactured. Next, to explain the coating strength of the magnetic disk according to the present invention manufactured in this way, a high-density head of 6000 BPI is used and the strength is 10 times that of a normal head load of 10.
The attached drawings show the results of the head crush resistance and abrasion resistance tests of the coating film when contact start/stop was performed over 00 days.

In this case, experiment A was manufactured according to the present invention, and dashed line B
The conventional method requires 15 to 60 minutes of abrasion treatment in a high-temperature furnace, and as a result, the number of contact starts and stops for the conventional method is about 20, whereas the present invention's method requires about 20 contact starts and stops. It can be seen that the coating can be applied 60 times, which is about three times as much, and the strength of the coating film is significantly increased. In addition, in the bending test of the paint film when the outermost part was bent 180 degrees using a palm tree, the paint film peeled off and could be easily removed by wiping the bent end with gauze. On the other hand, the material of the present invention does not cause such peeling and is strong against bending. As described above, according to the manufacturing method of the present invention, the strength of the coating film of the magnetic disk is increased, and since it does not contain hard additives such as alumina and silica, the magnetic head will not be destroyed.

In addition, the heat treatment time is short, which improves workability.

[Brief explanation of the drawing]

The attached drawing is a diagram showing the test results of the head crush resistance and abrasion resistance of the coating.

Claims (1)

[Claims] 1. A method for manufacturing a magnetic disk, which comprises applying a coating material containing at least a magnetic oxide and a thermosetting resin onto a substrate to form a coating film, and curing the coating film by baking it with a long-wavelength infrared heater. .