JPS59167837A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording medium which improves the lubricity and wear resistance of a magnetic layer and has excellent running stability and durability by having the magnetic layer incorporated therein with an org. compd. having a perfluoroalkyl group and a polyalkylene oxide group in a molecule. CONSTITUTION:A magnetic layer incorporated therein with an org. fluorine compd. such as (''Unidine DS401'' produced by Daikin Co., Ltd.) having a perfluoroalkyl group and polyalkylene oxide group in a molecule at 0.001-5pts.wt. by 100pts.wt. magnetic powder, together with a binder resin is formed on a base film. The org. fluorine compd. has adequate compatibility with a binder and a solvent for magnetic coating and provides excellent lubricity and wear resistance to the magnetic layer without bleeding out on the surface of the magnetic layer and without pinholing the magnetic layer. The magnetic tape or the like having excellent durability and running stability is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording medium, and an object thereof is to improve the lubricity and wear resistance of a magnetic layer, and to provide a magnetic recording medium that has excellent running stability and durability. be.

Generally, magnetic powder is placed on a substrate such as polyester film.
Magnetic recording media such as magnetic tapes, which are made by applying a magnetic paint consisting of a binder, an organic solvent, and other necessary components, run while coming into contact with magnetic heads, guide members, etc., so the coefficient of friction of the magnetic layer is small. The magnetic layer is required to have excellent running stability, and since it comes into violent sliding contact with a magnetic head during recording and reproduction, the magnetic layer is required to have excellent durability with little wear.

Therefore, as a measure to improve the lubricity and wear resistance of the magnetic layer, various lubricants have been incorporated into the magnetic layer. For example, silicone oil, which has a large lubricating effect, has been added to the magnetic layer. There are some things contained inside.

However, although silicone oil has excellent lubricity, it has poor compatibility with the binder, so although it can reduce the frictional resistance of the magnetic layer to some extent, it can make the magnetic layer inhomogeneous, causing pinholes and causing damage to the surface of the magnetic layer. The problem is that the magnetic layer tends to ooze out excessively, and because of this, the effect of improving the lubricity and wear resistance of the magnetic layer is not sufficient, and it cannot be said that running stability and durability can necessarily be improved. .

In view of the above circumstances, the inventors conducted various tests and found that when an organic fluorine compound having a perfluoroalkyl group and a polyalkylene oxide group in the molecule is contained in the magnetic layer, the compatibility with the binder increases. It was discovered that the solubility is good, and the lubricity and wear resistance of the magnetic layer can be sufficiently improved without excessive exudation or pinholes on the surface of the magnetic layer, and this invention has been made. .

Since the organic fluorine compound used in this invention has a polyalkylene oxide group, it is moderately compatible with various binders and organic solvents, and therefore does not excessively exude or cause pinholes on the surface of the magnetic layer. Never.

Furthermore, since these compounds have a perfluoroalkyl group with excellent lubricity, the lubricity and wear resistance of the magnetic layer are improved, and a magnetic recording medium with excellent running stability and durability can be obtained.

Such organic fluorine compounds can be widely used as long as they have a perfluoroalkyl group and a polyalkylene oxide group in the molecule, and a specific example of a commercially available product is Unidyne 1) 5401 manufactured by Daikin Industries, Ltd.
, 05402, trade name Megafac F17Q, manufactured by Dainippon Ink Chemical Co., Ltd.

Same F171. Examples include the F172 and F173.

The amount of the above-mentioned organic fluorine compound used is preferably 0.001 to 5 parts by weight per 100 parts by weight of the magnetic powder.If this amount is too large, the dispersibility may deteriorate or it may ooze out onto the surface of the magnetic layer, causing damage to the magnetic head. may contaminate the equipment and reduce output.

The magnetic powder applied to this invention includes 1-F e 203
゜Fe3O4 and their intermediate iron oxide powders, CO
In addition to magnetic iron oxide powder such as iron oxide powder containing
Any metal magnetic powder such as Fe, Ni or an alloy thereof can be used. Further, as the binder, any of various conventionally known resins can be used.

Next, embodiments of the invention will be described.

Example CO-containing r-Fe203 magnetic powder 80 weight i
Part VAGH (USA U, C1 (4), hinyl chloride-vinyl acetate-vinyl alcohol copolymer 10...
Bandex °r5250 (manufactured by Dainippon Ink Co., Ltd., urethane nilastone) 8.

Coronate, manufactured by Nippon Polyurethane Kogyo Co., Ltd., polyfunctional low molecular weight incyanate compound) 1I Organic fluorine compound (Unidyne L) 5401). ,. 5
Part by weight cyclohexanone 50
〃Methyl ethyl ketone 50
A magnetic paint was prepared by mixing and dispersing the mixture having the above composition in a ball mill for 70 hours. Apply this magnetic paint to a thickness of 11
After coating on a μm polyester film to a dry thickness of 5 μm, drying, and surface treatment, the thickness is 3.8 mm.
I cut it into widths and made magnetic tape.

Comparative Example A magnetic tape was prepared in the same manner as in the example except that in the composition of the magnetic paint in the example, one part of KF96 (dimethylsiloxane) manufactured by Shin-Etsu Chemical Co., Ltd. was used in place of the organic fluorine compound of the example.

The magnetic tapes obtained in the above Examples and Comparative Examples were tested for durability and measured for friction coefficients.

The durability test was conducted under the conditions of 35°C and 80% RH, with a head load of 10 g, and a running speed of 4.8 c1n/
This is done by running the magnetic tape for 2 seconds and reproducing it, and measuring the number of runs until the output drops by 3 dB from the initial output.The friction coefficient is determined after running the magnetic tape 200 times under the same conditions as the durability test described above. (The coefficient of friction with the air discharge head was measured.

Claims (1)

[Claims] (1) A magnetic recording medium having a magnetic layer containing an organic fluorine compound having a perfluoroalkyl group and a polyalkylene oxide group in the molecule.