JPS62222425A - magnetic recording medium - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic coating film used for magnetic disks and the like, and a method for producing the same.

[Conventional technology]

Porous with coated magnetic disk! ! A method for obtaining a 1JVT film is to mix an incompatible high-temperature volatile agent into the paint (as disclosed in JP-A+
1i56-3435) and a method of mixing an organic solvent adsorbent into the paint (Japanese Unexamined Patent Publication No. 6O-124024).

[Problem that the invention seeks to solve]

In the former method, an incompatible high-temperature volatile material that volatilizes at a higher temperature than the solvent used is used during the curing process, and the volatile material volatilizes to form holes in the process in which the solvent evaporates and curing begins.

With this method, it is difficult to control the hole diameter. The latter method takes advantage of the fact that the evaporation of organic solvents from activated carbon, silica gel, etc. deviates to a temperature several tens of degrees higher than the boiling point of the solvent, and such adsorbents are mixed into paints to remove solvents that are not adsorbed during the curing process. After the adsorbent evaporates and curing starts, the solvent adsorbed to the adsorbent evaporates while forming holes. The lubricant is deposited both in the holes formed in the coating binder and in the pores of the adsorbent. In this method, the diameter of the holes formed in the binder can be controlled by the pore size of the adsorbent, but at high recording densities, it is difficult to include non-magnetic materials such as adsorbents in the coating film. This will be disadvantageous in terms of recording characteristics.

An object of the present invention is to provide a porous magnetic disk coating film that is impregnated with a large amount of lubricant, has no adhesion, has high strength, and has excellent electromagnetic conversion characteristics.

[Means for solving problems]

The present invention supplements this point by forming a porous coating film on the substrate before forming the recording medium on the substrate,
If a paint containing recording material but no adsorbent is applied to the porous membrane, some of the solvent in the paint will be adsorbed by the adsorbent within the porous membrane, and will not be adsorbed during the curing process of the paint. This is based on new knowledge that after the solvent evaporates, it begins to volatilize in the temperature range where curing begins, forming holes in the coating film.

[Effect]

According to the above-described structure, the paint for forming the recording medium does not contain an adsorbent, and therefore, the volume of the formed porous recording medium is smaller than that of filler such as an adsorbent. Since no non-magnetic material is included, deterioration in electromagnetic conversion characteristics due to porosity can be minimized.

[Embodiments of the invention]

Example 1 10 parts by weight of activated carbon powder, 30 parts by weight of epoxy resin, PV
10 parts by weight of B, 30 parts by weight of phenolic resin, 200 parts by weight of solvent
A paint consisting of an amount of vL was prepared and spin-coated onto an aluminum substrate. After curing this at 220° C. for 2 hours, the surface was smoothed and a porous film with a thickness of 1 μm was formed. On this porous membrane, parts by weight of γ-FezOalOO, 15 parts by weight of alumina filler, 3 parts by weight of epoxy resin
0 parts by weight, 30 parts by weight of phenolic resin, 10 parts by weight of polyvinyl butyral resin, and 500 parts by weight of solvent (
The coating material (prepared by the same method as described in JP-A-60-124024) was woven using a spin cord, oriented in a magnetic field, cured at 220 DEG C. for 2 hours, and then processed to smooth the surface.

The sliding properties of the obtained magnetic disk were evaluated using an alumina slider (
A spherical surface with a radius of 30 Wn) was applied to the surface of the rotating disk under a load of 20 g, and the number of rotations until a sliding scratch occurred was evaluated, and the number of rotations was 4 x 104 times. Also, 2F output is 0
, 90 m Vp-p noise was 14 μVrms.

Figure 1 is a schematic cross-sectional view showing the coating structure according to the present invention, in which 10 is an aluminum substrate, 2o is a base layer binder, 21 is activated carbon, 22 is a hole formed in the process of volatilization of the solvent adsorbed on the activated carbon, 30 is a recording medium layer binder, 31 is a magnetic powder, 32 is a filler, and 33 is a hole formed by volatilization of the solvent adsorbed and held on the base 21° 22 during curing of the recording medium layer.

Comparative Example 1> γ-r/ax○5100 parts by weight prepared in the same manner as used in Example 1 and alumina 74 were added to an aluminum solder substrate.
915 parts by weight, 30 parts by weight of epoxy resin, 30 parts by weight of phenol resin, 10 parts by weight of polyvinyl butyral resin,
A paint consisting of 500 parts by weight of solvent was spin-coded, and after magnetic field orientation, it was cured at 220° C. for 2 hours to process the surface. Sliding scratches occurred after 2×104 times. 2F output is 0, 90m
Vp-p, noise was 14μVrinS.

Comparative Example 2> 2 parts by weight of activated carbon prepared in the same manner as used in Example 1, parts by weight of γ-FezOalOO,
Alumina 74515 parts by weight, epoxy resin; 30 parts by weight, phenolic resin 30 parts by weight, polyvinylbutinol 1
A paint consisting of 0 parts by weight of solvent and 500 parts by weight of solvent was oriented using a spin cord in a magnetic field and then cured at 220° C. for 2 hours to process one surface. Sliding scratches occurred after 4×104 times. 2F output is 0.
90 mVp-p, noise was 16 μVrms.

〔Effect of the invention〕

By forming a porous membrane on the base layer according to the present invention,
With the same strength as when adsorbent is mixed into the recording media coating,
A recording medium with 10% less noise could be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing the coating structure according to the present invention. 1o... Aluminum substrate, 20... Base layer binder °-
121... Activated carbon, 22... Holes formed in the process of volatilization of the solvent adsorbed on the activated carbon, 30... Recording medium layer binder, 31... Magnetic powder, 32... Filler, 33... ...During the curing of the recording medium layer, the adsorption rate l on the base 21.22

Claims (1)

[Claims] 1. On an aluminum substrate, at least one of activated carbon, silica gel, and γ alumina, and at least one of single crystal α alumina with a particle size of 0.5 to 10 μm, SiC, and ZrO_2 are coated with an epoxy resin, It is dispersed and suspended in a solution consisting of polyvinyl butyral resin, phenolic resin, and a solvent, and then applied and cured on the substrate, and if necessary, a surface smoothing process is performed to form a base layer with a thickness of 0.5 to 10 μm. A step of forming at least magnetic powder and an epoxy resin on the underlayer.
A magnetic recording medium characterized in that it is prepared by a process of coating, orienting, and curing a magnetic paint made of polyvinyl butywool resin, phenol resin, and a solvent to form a magnetic cloth film, and a processing process. 2. The magnetic recording medium according to item 1, wherein particles of one or more types of alpha alumina, SiC, or ZrO_2 used to form the underlayer are also contained in the magnetic coating film. 3. The magnetic recording medium according to item 1, wherein the particles of one or more types of α-alumina, SiC, or ZrO_2 used to form the sample layer have a structure that protrudes from the surface of the magnetic coating film.