JPS6246434A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To substantially decrease coefft. of friction by forming a thin ferromagnetic metallic film layer consisting of a metal contg. cobalt as an essential component on a substrate and forming a lubricating agent layer thereon, then subjecting said layer to a moisture sticking treatment. CONSTITUTION:The thin ferromagnetic metallic film layer 2 consisting of the metal contg. cobalt as the essential component is formed on the substrate 1. The treatment to stick moisture onto the lubricating agent layer 3 formed on the thin metallic film layer 2 is executed by exposing the layer 3 to steam kept at >=40 deg.C temp. and >=70% relative humidity or spraying >=40 deg.C water grains to the layer 3 or immersing the layer 3 into >=40 deg.C water. The lubricating agent layer subjected to such moisture sticking treatment is improved in the adhesiveness of the layer 3 to the layer 2 by the synergistic interaction of the moisture sticking to the layer 3 and the lubricating agent layer; in addition, the lubricating effect of the layer 3 is extremely satisfactorily provided, by which the coefft. of friction is thoroughly decreased and the running stability and wear resistance are improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a magnetic recording medium having a ferromagnetic metal thin film layer as a magnetic recording layer, and more specifically relates to a method for manufacturing a magnetic recording medium having a small coefficient of friction, high running stability and The present invention relates to a method of manufacturing the above-mentioned magnetic recording medium having excellent durability.

[Conventional technology]

A magnetic recording medium whose magnetic recording layer is a ferromagnetic metal thin film layer is
It is usually made by depositing metals or their alloys on a base film by vacuum deposition, sputtering, etc., and has characteristics suitable for high-density recording, but on the other hand, the coefficient of friction with the magnetic head is large, causing wear and tear. The problem is that it is easily damaged and has poor running stability and durability.

For this reason, efforts have been made to improve durability and corrosion resistance by coating various lubricants on the ferromagnetic metal thin film layer to provide a protective film layer with good lubricity.For example, myristic acid It has been proposed to provide a lubricant layer with good lubricity on a ferromagnetic metal thin film layer by depositing a fatty acid such as ferromagnetic metal. (Japanese Patent Publication No. 56-30609) [Problems to be Solved by the Invention] However, in the case where a lubricant layer made of this type of fatty acid is provided on a ferromagnetic metal thin film layer, the lubricant layer has a lubricating effect. Although the wear resistance has been improved, the coefficient of friction has not yet been sufficiently reduced, and running stability and durability have not been sufficiently improved.

[Means for solving problems]

This invention was made as a result of extensive research in view of the current situation, and involves forming a ferromagnetic metal thin film layer made of a metal whose main component is cobalt on a substrate, and then depositing a ferromagnetic metal thin film layer on this ferromagnetic metal thin film layer. After applying a lubricant to form a lubricant layer, a moisture adhesion treatment is performed at a temperature of 40°C or higher to remove the lubricant layer on the ferromagnetic metal thin film layer and the moisture attached to the lubricant layer. Due to the synergistic effect of the lubricants, the lubricating effect of the lubricant is fully exhibited, the coefficient of friction is sufficiently reduced, and running stability and wear resistance are sufficiently improved.

In this invention,
; The lubricant layer is treated with water vapor at a temperature of 40°C or higher and a relative humidity of 70% or higher.
IIH:l:g6tka1, alloy Lt? ! i
l? *'iP'IN&:&Kl><40,.
I□Tsuyo. . , 2 q ”) c18 KA 1.6.4 YO 2 1 □ i If the water is immersed in water with a temperature of 40°C or higher, and such moisture adhesion treatment is performed, - adhesion to the lubricant layer. The moisture absorbed by the lubricant layer interacts synergistically with the lubricant layer and the ferromagnetic metal thin film layer.
1 has been improved, and the lubricating effect of the lubricant layer is extremely good, and the coefficient of friction is sufficiently reduced, resulting in 7. Stable running +! -75 Abrasion resistance 7' Full direction J''1
do.
: In this kind of moisture adhesion treatment, the temperature should be lowered to 4
If carried out at a temperature lower than 0°C, moisture adhesion on the surface of the lubricant layer,
It is preferable to carry out the process at a temperature of 40°C or higher, and the higher the temperature, the better the results. is obtained. Particularly in water vapor: When exposed to water vapor, the temperature should be 40°C or higher and the relative humidity should be 70% so that sufficient moisture 1 is attached and retained on the surface of the lubricant layer.
It is preferable to carry out exposure to the above water vapor, and the higher the relative humidity and the higher the temperature, the better the results will be obtained.

The lubricant layer subjected to such moisture adhesion treatment is
For example, a ferromagnetic metal thin film layer is dissolved in an appropriate solvent such as toluene, methyl isobutyl ketone, methyl ethyl ketone, cyclohexanone, ethyl acetate, isopropyl alcohol, Freon, tetrahydrofuran, dimethyl formamide, dioxane, etc., and the ferromagnetic metal thin film layer is immersed in the solution obtained by dissolving. The lubricant may be formed by crushing, or by coating or spraying the solution on the ferromagnetic metal thin film layer, or by vacuum depositing a lubricant onto the ferromagnetic metal thin film layer. The lubricant layer thus formed on the ferromagnetic metal thin film layer has an excellent lubrication function, and when the above-mentioned moisture adhesion treatment is performed on this lubricant layer, it synergizes with the attached moisture. It interacts with the ferromagnetic metal thin film layer with good adhesion and is deposited on the ferromagnetic metal thin film layer, and the lubricating function is further improved, the coefficient of friction is sufficiently reduced, and running stability and wear resistance are improved. be done.

Suitable lubricants used include aliphatic lubricants, fluorine-based lubricants, silicone-based lubricants, and hydrocarbon-based lubricants. Among the aliphatic lubricants, lauric acid , myristic acid, valmitic acid,
Fatty acids such as stearic acid and behenic acid, metal salts of fatty acids such as zinc stearate and cobalt stearate, fatty acid esters such as n-butyl stearate and octyl myristate, fatty alcohols such as stearyl alcohol and myristyl alcohol, trimethyl Examples include chlorides such as stearyl ammonium chloride and stearoyl chloride, and amines such as stearylamine, stearylamine acetate, and stearylamine hydrochloride. In addition, as the fluorine-based lubricant, perfluoropolyether, perfluoroalkyl polyether, perfluoroalkyl carboxylic acid, etc. are preferably used, and specific examples of commercially available products include Daikin Co., Ltd. Daifluoril #20, Dupont Co., Ltd. Examples include Talaito Sox M, Talaito Sox H1 Vydax AR, manufactured by Montegisson, and Fomblin Z, manufactured by Montegisson. Furthermore, silicone-based lubricants include silicone oil, modified silicone oil, and the like, and hydrocarbon-based lubricants include paraffin, squalane, wax, and the like.

When used, one type or a mixture of two or more of them is used, and the coating amount is 20 to 1
It is preferable to apply the coating within a range in which a film of 1,000 yen is formed.If the film thickness is thinner than 20 yen, the excellent lubricating effect cannot be fully exhibited and the coefficient of friction cannot be sufficiently reduced. If it is thicker than normal, the spacing loss will be too large, which will have a negative effect on the electromagnetic conversion characteristics.

Materials for forming the ferromagnetic metal thin film layer include CO alone,
Co-Cr alloy containing Co as a main component, Co-Ni alloy, Co-P alloy, Co-Fe alloy, Co-Fe-Cr
Co alloys such as alloys are preferably used, and these ferromagnetic materials are deposited on the base film by means such as vacuum deposition, ion blating, spankling, and coating, and are coated with Co-based metals. A ferromagnetic metal thin film layer is formed.

In addition, as magnetic recording media, polyester film,
Structures that come into sliding contact with magnetic heads, such as magnetic tapes based on synthetic resin films such as polyimide films, magnetic disks and drums based on disks or drums made of synthetic resin films, aluminum plates, glass plates, etc., and magnetic cards. It includes various forms of.

〔Example〕

Next, embodiments of the invention will be described.

Example 1 A polyester film with a thickness of 10 μm was loaded into a vacuum deposition apparatus, and a cobalt-nickel alloy (molar ratio 80:20) was heated and evaporated under a vacuum of 5×10 −5 Torr to deposit a 150 μm thick polyester film onto the polyester film. A ferromagnetic metal thin film layer made of a cobalt 12.7 Kel alloy was formed. Then,
A 0.11°C mass % methyl isobutyl ketone solution of stearic acid is applied onto this ferromagnetic metal thin film layer and dried to form a lubricant layer of stearic acid with a thickness of 100 mm.
Subsequently, this was exposed to saturated steam at 60° C. for 5 hours to perform a moisture adhesion treatment. Thereafter, it was cut to a predetermined width to produce a magnetic tape A in which a ferromagnetic metal thin film layer 2 and a lubricant layer 3 were sequentially laminated on a polyester film 1 as shown in FIG.

Example 2 In the lubricant layer formation and moisture adhesion treatment in Example 1, a 0.1% by weight Freon solution of perfluoroalkyl carboxylic acid was used in place of the 0.1% by weight methyl isobutyl ketone solution of stearic acid. A magnetic layer was prepared in the same manner as in Example 1, except that a lubricant layer with a thickness of 100 μm consisting of perfluoroalkyl carboxylic acid was formed, and the moisture adhesion treatment was performed by exposing it to saturated steam at 80° C. for 1 hour. I made tape A.

Example 3 In the moisture adhesion treatment in Example 1, magnetic tape A was prepared in the same manner as in Example 1, except that instead of being exposed to saturated steam at 60°C for 5 hours, water droplets at 80°C were sprayed for 15 minutes. I made it.

Example 4 In the moisture adhesion treatment in Example 1, instead of being exposed to saturated steam at 60°C for 5 hours, it was exposed to water at 60°C for 30 hours.
Magnetic tape A was prepared in the same manner as in Example 1, except that the tape was immersed for a minute.

Comparative Example 1 A magnetic tape was produced in the same manner as in Example 1, except that the water adhesion treatment for the lubricant layer was omitted.

Comparative Example 2 A magnetic tape was produced in the same manner as in Example 2, except that the water adhesion treatment for the lubricant layer was omitted.

Regarding the magnetic tapes obtained in each example and comparative example,
The friction coefficient and still life were measured.

The table below shows the results.

〔Effect of the invention〕

As is clear from the above table, the magnetic tapes obtained in this invention (Examples 1 to 4) are the same as Comparative Examples 1 and 2.
Compared to the magnetic tape obtained in It can be seen that the following can be obtained.

[Brief explanation of drawings]

FIG. 1 is a partially enlarged sectional view of a magnetic tape obtained by the present invention. DESCRIPTION OF SYMBOLS 1... Polyester film (substrate), 2... Ferromagnetic metal thin film layer, 3... Lubricant layer, A... Magnetic tape (magnetic recording medium)

Claims (1)

[Claims] 1. A ferromagnetic metal thin film layer made of a metal whose main component is cobalt is formed on a substrate, and then a lubricant is deposited on the ferromagnetic metal thin film layer to form a lubricant layer. After forming, 40℃
Method 2 for manufacturing a magnetic recording medium characterized by performing moisture adhesion treatment at a temperature of 40°C or more and a relative humidity of 7.
The method 3 for manufacturing a magnetic recording medium according to claim 1, which is performed by exposing the lubricant layer to water vapor of 0% or more, the water adhesion treatment is carried out by blowing water droplets at a temperature of 40° C. or more onto the lubricant layer. A method 4 for producing a magnetic recording medium according to claim 1, wherein the moisture adhesion treatment is performed by immersing the lubricant layer in water at a temperature of 40° C. or higher. Method for manufacturing magnetic recording media