JPS6059521A - 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] The present invention relates to magnetic recording media.

Electroless cobalt-based plating films are widely used as high-density magnetic recording media, and recently, vapor-deposited films are also attracting attention as long-term recording tapes that can replace coated tapes.

The present inventor has conducted various studies regarding such cobalt films, and the present invention has been made as part of this research.

That is, 1. The gist of the present invention is a magnetic recording characterized in that palladium is attached to the surface of a plastic substrate, and then a magnetic metal layer containing cobalt, manganese and/or zinc is formed by electroless plating. It's in the medium.

The present invention will be explained in detail below.

First, the plastic substrate used in the present invention is usually made of polyester or polyimide resin from the viewpoint of adhesion with the magnetic layer, heat resistance, cost, etc.

Biaxially oriented polyethylene terephthalate is preferably used. The thickness is usually selected from about t-200μ.

In the present invention, on such a plastic substrate,
Palladium is deposited by sputtering or ion blating to impart catalytic activity for forming the magnetic metal layer.

When using the sputtering method, a direct current method or a high frequency method is usually used depending on the type of power source used.

The degree of vacuum is usually 10-' to io-'To in the case of the DC method.
rr, and in the case of the A frequency method, it is about 10-2 to 10-' Torr.

In addition, when using the ion plate ink method, the degree of vacuum is usually selected from 70-2 to 70''3 Torr for the DC method and 10-3 to 0'' Torr for the high-frequency method. Palladium to be coated The thickness is usually 5~.

In the present invention, a magnetic metal layer containing cobalt, manganese and/or zinc is then formed on the substrate-1 by electroless plating.

That is, the substrate is immersed in an electroless plating bath, and the bath composition,
By maintaining appropriate conditions, the magnetic metal layer can be formed on the surface of the substrate.

As a plating bath, in addition to cobalt salt, manganese salt and/or
Alternatively, an alkaline bath containing zinc chloride may be used. As the alkaline bath, an ammonia alkaline bath or a caustic alkaline bath is usually used, and an ammonia alkaline bath is preferred from the viewpoint of bath stability.

Furthermore, hypophosphite or the like is used as a reducing agent, and citric acid or tartaric acid or the like is used as a complexing agent.

In particular, in the case of ammonia-alkaline baths using sulfates as salts of cobalt, manganese or zinc and tartaric acid as complexing agent, the resulting a-air recording medium has the best properties.

The temperature of the bath is usually about 15-9.5;C, and the pH is 7-9.
Selected from about 1.

The thickness of the magnetic metal layer is usually about 00/-3μ, preferably about 0.05-/μ.

In the magnetic metal layer, the cobalt content is usually 30%.
or more, preferably 70% or more.

Manganese and zinc can be contained up to about 3% and 10%, respectively, and the phosphorus content is usually selected from about λ to t%. Of course, it may also contain other metals such as nickel.

Through electroless plating, metal ions such as cobalt are deposited on the substrate surface to form a magnetic metal layer.

The obtained magnetic recording medium has particularly excellent mechanical properties without impairing electromagnetic conversion properties, and also has good environmental resistance.

In other words, the elongation at break is significantly improved.

Since it also has good sliding properties (wear resistance) with a magnetic head, it is particularly useful as a magnetic recording tape that involves high-speed, long-time running.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 Palladium with a thickness of about SOX was sputtered (DC SO
o v, degree of vacuum! ;
Electroless plating was performed using the bath shown in Table 1 at a pH of 0.0 (adjusted with NH4OH) and a temperature of SO 0 C for approximately S minutes.

4- Table l Magnetic metal layer (Co-Zn-P) of the obtained magnetic recording medium
The thickness was OISμ.

Example In Example 1, ZnSO4 plating was performed as a bath component.

The thickness of the magnetic metal layer (Co-Mn-P) is 0. /! ;
The electromagnetic conversion characteristics, mechanical characteristics, and ml environmental properties of the magnetic recording media obtained in Reference Example and Example 2 were examined.

In addition, the coercive force (He) was measured using a B-H Lube laser (external magnetic field 1 x 10' A/m), and the elongation was measured using an Instron type ledger tester. is H after holding in a high temperature and high humidity environment (373K, 90%)
It was measured by the change in a.

(1) Coercive force (He): (Oe) Co -Zn -P about lθθO Co -Mn -P about A θO Note that the edge roughness of the magnetic metal layer is 000 by using the same method as in Example/λ! i, 0. / , 0.2, θ3 and 0,3 p
magnetic recording media (Co-Zn-P and Co-Mn-P)
When Y was prepared and the holding force was measured in the same way, those with a thickness of 02 or more were the same as the above values (i.e., T(c
is constant when the membrane pressure is θ15μ or more).

(2) Elongation at break: For both Co-Zn-P and Co-Mn-P, the elongation at break (approximately 70%) of the substrate (polyethylene terephthalate) was so large that it was impossible to measure the elongation.

For comparison, znSO4 (73mo
l/? 7Z') instead of l) Ni 804
(5mol/ri) ti) Na25n03 (
Co-N1-P and Co-8n-p films with a thickness of 75 μm were formed in the same manner using 13 mol/m')', and the elongation was measured. The results show that Co-Ni-P:
/ 3%, and Co-8n-P 0%.

(3) Environmental resistance: The decrease in Ha after holding for i6g hours was at a level that caused no practical problems.

Applicant: Mitsubishi Chemical Industries, Ltd. Agent Patent Attorney Hase - 1 other person

Claims (1)

[Claims] (1) A magnetic recording medium characterized in that palladium is attached to the surface of a plastic substrate, and then a magnetic metal layer containing cobalt, manganese and/or zinc is formed by electroless plating.