JPS62246123A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain good image quality in the stage of still reproduction under low humidity and to extend and stabilize the life of a titled medium by forming a thin layer contg. a fluorinated phenyl deriv. on a thin ferromagnetic metallic film contg. oxygen. CONSTITUTION:The thin film contg. the fluorinated phenyl deriv. expressed by the formula I or II is formed on the thin ferromagnetic metallic film contg. oxygen. In the formulas I, II R<1>, R<3> denote a fluorine atom or residual fluorinated hydrocarbon group of 1-22, l denotes 1-5 integer, P denotes 1-4 integer. R<2>, R<4> denotes a hydrogen atom or residual hydrocarbon group of 1-22C, m denotes 5-l integer, q denoted 4-p integer, and A-C denote an org. polar group having the atom of any among oxygen, nitrogen, sulfur and phosphorus at the bond terminal. The this ferromagnetic metallic film is adequately a thin metallic film which consists essentially of Co, etc., and is formed by, for example, a diagonal or vertical vapor deposition method or a thin metallic film which consists essentially of Co, etc. and contains the oxygen obtd. when an atmosphere perdominated by gaseous oxygen is used for the atmosphere in the stage of film formation.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention is suitable for magnetic recording media such as magnetic tapes and magnetic disks, and particularly relates to a magnetic recording medium suitable for rotary head type video tape recorders.

[Conventional technology] Balt, nickel, iron, or alloys containing these as main components are used to produce polymer films such as polyester films, polyimide films, non-magnetic metal thin sheets, etc. using vacuum film-forming methods such as vacuum evaporation, sputtering, and ion blasting. A ferromagnetic metal thin film magnetic recording medium formed on a substrate made of ferromagnetic metal can dramatically improve recording density compared to conventional coated magnetic recording media. To achieve this, it is necessary to make the surface of the magnetic recording medium as flat as possible to reduce the spacing loss between the magnetic head and the magnetic recording medium as much as possible.

However, if the surface is flattened too much,
This may impede the running performance and extremely shorten the playback life, especially in the still mode of video signal playback, so the surface of the magnetic recording medium is usually finely roughened and at the same time various types of organic abrasions are applied. These problems have been solved by providing a surface coating layer made of resin or the like. Various fatty acid esters are used as such surface coating materials.

Lubricants such as fatty acid amide, silicone oil, and fluorine oil, and resins such as polyamide resin and epoxy resin have been used singly or in various composite forms.〇Problems to be solved by the invention When looking at still regeneration life All of the above-mentioned surface coatings usually have a lifespan of 3Q minutes or more at normal temperature and humidity, but when the humidity drops below 20%RH, and even below 15%RH, the lifespan decreases to 3Q minutes or less. As a result of the studies conducted by the present inventors, it has become clear that many white spots running horizontally appear in the reproduced image, even if they do not deteriorate.

Means for Solving the Problems The present invention relates to a magnetic recording medium characterized in that a thin layer containing a fluorinated phenyl derivative is formed on a ferromagnetic metal thin film containing oxygen. The above-mentioned problems have been solved by the phenyl derivative's strong protective action on the surface of magnetic metals under low humidity conditions.

In the present invention, the following general formula (I) or (■) is applied on a ferromagnetic metal thin film that has improved surface hardness and corrosion resistance and adhesion of two surface coating materials by incorporating oxygen.

General formula (I), general formula (■): [However, in general formula (I) or (II), R1
and R3 represents a fluorine atom or a fluorinated hydrocarbon residue having 1 to 22 carbon atoms, 1 represents an integer of 1 to 6, and p represents an integer of 1 to 4.

R2 and R4 are hydrogen atoms or have 1 to 22 carbon atoms
represents a hydrocarbon residue, m represents an integer of 6-1,
q represents an integer of 4-p.

n, r, and S each represent an integer from 0 to 1o.

m , u , and V each represent an integer of 0 or 1. OA, B, and C represent a polar group having a bond terminal with any one of oxygen, nitrogen, sulfur, and phosphorus. ] A thin layer containing a fluorinated phenyl derivative represented by the following is formed.

Function: Due to the above structure, the fluorinated phenyl derivative has a strong protective effect on the surface of magnetic metal under low humidity and a lubricating effect, making it stable under low humidity environment where ferromagnetic metal tends to adhere to the magnetic head. This maintains still playback durability.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings.

The figure shows the basic configuration of a magnetic recording medium in an embodiment of the present invention. In the figure, 1 is a substrate, 2 is a ferromagnetic metal thin film, and 3 is a surface coating layer. The surface coating layer 3 is composed of a thin film layer containing a 7-nominated phenyl derivative.

Examples of the above-mentioned fluorinated phenyl derivatives used in the present invention include: (I) Carboxylic acids FF FF (2) Alcohols FF FF (3) Phosphoric acids (4) Aminoamides FF FF (6) Esters (7) ) Mercaptans, etc. The 7-nominated phenyl derivative used in the present invention has at least one fluorophenyl group, fluoroalkylphenyl group, fluorophenylene group, 6- or fluoroalkylphenylene group, and these It is suitable that the molecular weight of the group accounts for 5% or more of the total molecular weight. If this ratio is 6% or less, the effects of the present invention cannot be obtained. As seen in some of the above examples, the lubricity of the fluorinated phenyl derivative itself can be further improved by incorporating a long-chain half-0-roalkyl group or an aliphatic alkyl group.

On the ferromagnetic metal thin film, the fluorinated phenyl derivative is applied alone at a rate of 0.1 to 500 wJ per m5 of surface, more preferably O,S to 2007+19, or other lubricants, rust preventives, resins, etc. It is preferable to have it exist in a thin layer as a complex with. In addition to coating or vapor-depositing it directly on the ferromagnetic metal thin film, there are other methods for making it exist, such as coating or vapor-depositing it on the back side of the magnetic recording medium and then applying it to the back surface of the magnetic recording medium when stacking (winding) the magnetic recording medium. A method of transferring it onto the surface of a ferromagnetic metal thin film is also possible.

The ferromagnetic metal thin film may be, for example, a metal thin film mainly made of Co, Ni, Fe, etc. formed by oblique evaporation or vertical evaporation, or a metal thin film mainly made of alloys thereof (e.g. CoNi, CoCr, etc.). A suitable material is one containing oxygen, which can be obtained when the atmosphere during film formation is such that oxygen gas becomes oxidizing. The oxygen content is suitably at least 3% or more, preferably 6% or more in terms of atomic ratio to the ferromagnetic metal. If it is less than 3%, the effects of the present invention cannot be obtained.

As a substrate on which a ferromagnetic metal thin film is to be formed, it is appropriate to use one that has good macroscopic surface smoothness and has minute protrusions, for example, a substrate with a height of 60 to 600 cm.
Polyester films having an average of I x 10' to 108 corrugations or peaks per m2 are particularly preferred.

Wavy protrusions (height: 100, human density: 1 x 106 CoNi ferromagnetic metal thin film (Ni=20%, film thickness 1
000) were formed in the presence of trace amounts of oxygen. The oxygen content 1ii in the film was 5% in terms of atomic ratio. This sample is designated as A.

There are several granular protrusions (average height: 70 people, average diameter: 1) per 100 pm'' of surface with a gentle gradient due to silica fine particles added to the polyester film, and relatively small protrusions due to fine particles caused by polymerization catalyst residues. On the surface of the polyester film, which reduces large protrusions as much as possible, 1 steep mountain-like protrusions are formed using colloidal silica particles with a diameter of 150A as cores and UV-curable epoxy resin as a binder.
A CoN i film (N l = 201 + film thickness 1000A, oxygen content 7%) was formed on the substrate on which X 10'/2 depressions were formed under the same conditions as above.
shall be.

Further, as a comparative example, C is a sample B in which no oxygen was introduced during vapor deposition (B only the oxygen content was 2% or less). A solution of various fluorinated phenyl derivatives prepared in advance was coated on these deposited films to form a thin layer, and then cut into a predetermined width to make a magnetic tape, which was then assembled into a prototype video deck at 20C: 15% RH. The still reproduction characteristics were measured, and the time at which horizontal white spots began to appear in the reproduced image (white spot generation time) and the time at which the reproduced image began to become completely distorted (lifetime) were determined. The results are summarized in the table below. As a comparative example, perfluoroalkyl group-containing fluorine-containing derivatives containing no fluorinated phenyl group, ... (I2), (I3
), (I4), higher aliphatic acids and their derivatives,...
...(IS), magnetic film with low oxygen content...
(7) etc. are added.

Effects of the Invention As is clear from the above description, the magnetic recording medium of the present invention has excellent image quality during still reproduction under low humidity, and has a long and stable lifespan, making it extremely valuable industrially. is higher than 0

[Brief explanation of drawings]

The drawing is a sectional view of one embodiment of the magnetic recording medium of the present invention. 1...substrate, 2...ferromagnetic metal thin film,
3...Surface coating layer. Name of agent: Patent attorney Toshio Nakao and 1 other person1-
---Ichiban Rebellion 2----The most powerful B-sexuality is tortured 3--...

Claims (1)

[Scope of Claim] A magnetic recording medium characterized in that a thin layer containing a fluorinated phenyl derivative represented by the following general formula (I) or (II) is formed on a ferromagnetic metal thin film containing oxygen. General formula (I): ▲There are mathematical formulas, chemical formulas, tables, etc.▼ General formula (II): ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [However, in general formula (I) or (II), R^
1 and R^3 represent a fluorine atom or a fluorinated hydrocarbon residue having 1 to 22 carbon atoms, 1 represents an integer of 1 to 5, and p represents an integer of 1 to 4. R^2 and R^4 are hydrogen atoms or have 1 to 2 carbon atoms
2 represents a hydrocarbon residue, m represents an integer of 5-1, and q represents an integer of 4-p. n, r, and s each represent an integer from 0 to 10. m, u, and v each represent an integer of 0 or 1. A, B, and C represent a polar group having any one of oxygen, nitrogen, sulfur, and phosphorus atoms as a bond terminal. ]