JPS60226021A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To prevent reduction in the quality of sound and image due to stain and friction or reduction in the reliability of a magnetic recording medium by forming a coated fluororesin layer on the magnetic layer of the magnetic recording medium. CONSTITUTION:A magnetic layer 2 is formed on a substrate 1 by coating, vapor deposition, sputtering or plating. The thickness of the layer 2 is usually regulated to about 0.1-10mum but can be reduced to <=0.1mum according to a method applied. A coated layer 3 of fluororesin is then formed on the magnetic layer 2 by a conventional coating method such as roll coating, spray coating or doctor knife coating. It is desirable that the layer 3 is made as thin as possible, and the thickness of the layer 3 should be restricted to several mum, desirably submicron order.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applicable to magnetic tapes or magnetic disks attached to magnetic recording devices such as audio recorders, video tape recorders, and computers. This is related to the improvement of

Conventional technology Audio/visual equipment such as audio tape recorders and video tape recorders, computers, etc.
Magnetic tapes or magnetic disks are used as recording media, and recently there has been an extremely strong demand for higher density and higher speed.

Therefore, in addition to improving magnetic heads, efforts are being made to make the magnetic layer thinner and improve the coating media that make up the magnetic layer. There is a need to improve sound quality and image quality.

However, even with these improvements in magnetic heads and magnetic tapes, it is difficult to eliminate dirt on the magnetic head due to dirt on the magnetic tape and friction between the magnetic tape and the magnetic head. This adversely affects sound quality, image quality, or reliability, and has a negative effect on the life of the magnetic head, the life of the magnetic tape, and the life of the battery that drives the magnetic tape. Incidentally, although magnetic cards are not required to have such a high density, reliability is extremely important, and it is necessary to prevent deterioration in reliability due to dirt on the magnetic card or physical damage during handling as much as possible.

Problems to be Solved by the Invention The present invention solves problems such as deterioration of sound quality, image quality, and reliability due to dirt and friction by providing a specific coating layer on the magnetic layer constituting the magnetic recording medium. This was an attempt to solve the problem by providing a .

Means for Solving the Problems The gist of the present invention is a magnetic recording medium having a structure in which a fluororesin coating layer is provided on a magnetic layer of the magnetic recording medium.

The fluororesin used in the present invention includes a tetrafluoroethylene homopolymer or copolymer,
Examples include homopolymers or copolymers of vinylidene fluoride, homopolymers or copolymers of chlorotrifluoroethylene, and in particular, tetrafluoroethylene homopolymers and tetrafluoroethylene copolymers in an appropriate ratio, especially in a weight ratio of 85:5 to 85:5. to: so,
It is preferable to mix and use them at a ratio of <130:10 to 20:80. Examples of the comonomer include olefins, fluorine-containing olefins, perfluoroolefins, and fluoroalkyl vinyl ethers. In addition, a homopolymer of tetrafluoroethylene and a fluorine-based surfactant are mixed in an appropriate ratio, especially a weight ratio of 85%.
:5~10:90, Nakanzu〈θ0:10~20:80
It is preferable to use them in a mixed manner.

Furthermore, it is also preferable to use a mixture of a tetrafluoroethylene copolymer and a fluorosurfactant together with a tetrafluoroethylene homopolymer.

These fluororesins are used as a solution or dispersion for coating purposes, but they do not attack the magnetic layer;
From the viewpoint of coating workability and environmental non-contamination, it is particularly desirable to apply the coating as an aqueous dispersion.

It is preferable that this aqueous dispersion further contains a silicon resin such as silicone oil, silicone grease, oil compound, silicone varnish, etc., and various anionic, nonionic, cationic or amphoteric surfactants. , fluorine-based solvents, saturated hydrocarbon-based solvents, polyhydric alcohols, brighteners, viscosity modifiers, waxes, stabilizers, and the like.

The magnetic recording medium of the present invention is manufactured by providing a magnetic layer on a base material and further providing a fluororesin coating layer thereon.

In the case of magnetic tape, the base material is polyester film, diacetate film, triacetate film,
Rigid polyvinyl chloride finochim, polycarbonate film, polypropylene film, polyimide film,
In the case of magnetic disks, aluminum substrates such as glass fiber reinforced polyester films are often used.

In the case of audio magnetic tape, the magnetic materials constituting the magnetic layer include γ-iron oxide, chromium oxide, cobalt-containing γ-iron oxide, cobalt-nickel, iron/cobalt/copper, and iron/cobalt/copper.・In the case of magnetic tape for video, such as Nikke J, γ-iron oxide, cobalt-containing γ-iron oxide, oxidized konokuruto, co/<)reto nickel, iron heat cobal)-
In the case of computer magnetic disks, γ-iron oxide is often used, such as copper, iron, copper, etc. For magnetic disks for computers, γ-iron oxide is often used.
z%t±monk)! ! This is usually done by depositing, sputtering or plating. The thickness of the magnetic layer is often about 0.1 to 10 microns, but according to method (2), it can also be reduced to 0.1 microns or less. In addition,
In the case of the coating method (2), vinyl chloride resins, acrylic resins, urethane resins, epoxy resins, melamine resins, etc. are used as binders, and these binders contain various additives such as plasticizers and stabilizers. , lubricants, dispersants, antistatic agents, etc.

For installing the fluororesin coating layer on the magnetic layer, any of the usual coating methods, including the roll coach ink method, spray coating method, and doctor knife method, can be used. The thickness of this coating layer is desirably as thin as possible, and should be kept on the order of several microns, preferably submicrons. Note that a fluororesin coating layer may also be provided on the opposite side of the magnetic layer of the base film constituting the magnetic tape.

FIG. 1 is a schematic cross-sectional view showing an example of the magnetic recording medium of the present invention, in which (1) is a base material, (2) is a magnetic layer, and (3) is a fluororesin coating layer.

Effects of the Invention In the magnetic recording medium of the present invention, a protective layer of micron or submicron order is formed by a fluororesin coating layer on the magnetic tape, magnetic disk, floppy disk, magnetic card, etc. sent to the magnetic head. However, the adhesion between the fluororesin coating layer and the magnetic layer is good, and not only does the presence of the fluororesin coating layer have no negative effect on sound or image quality, but
This protective layer's excellent slipperiness, antifouling properties, resistance to changes in temperature and humidity, and anti-damage properties prevent the magnetic head and magnetic tape from getting dirty or scratched, and prevent friction between the magnetic tape and the magnetic head. As a result, the magnetic layer can be made thinner more easily, improving the reliability of recording and erasing, and improving the sound and image quality. The lifespan of batteries that drive tapes and the like will also be significantly extended.

Industrial Application Field The magnetic recording medium of the present invention can be used as a magnetic tape, a magnetic disk, a floppy disk, which is attached to a magnetic recording device such as an audio tape recorder, a video tape recorder, a combination unit, or a word processor, or a cash card, a credit card, or an electronic device. It is useful as a program card for microwaves, sewing machines, etc., a paper card for expressways, a magnetic card for train tickets, commuter passes, price tags, etc.

EXAMPLES Next, the magnetic recording medium of the present invention will be further explained with reference to Examples.

Example 1 An audio magnetic tape was prepared in which a 5 micron thick coated layer of chromium oxide was formed on a 16 micron thick polyester stretched film tape, and a fluorine film having the following composition was coated on the magnetic layer of this magnetic tape. An aqueous resin dispersion was coated to a dry thickness of about 1 micron.

Fluoroethylene h Tetrafluoroethylene homopolymer 6% Tetrafluoroethylene-hexafluoropropylene copolymer 5% Paraffinic midpoint solvent 25% Brightener, surfactant, viscosity modifier, stabilizer 9% Water 55% Such The magnetic tape of this composition was attached to a portable cassette tape recorder, and the deterioration of sound quality and battery life were investigated over a long period of time. Since it will not be damaged, the period until noise occurs will be significantly extended,
Also, since the magnetic tape can be fed smoothly, the battery life is 3.
It was found that the period of time was increased by ~40%.

Example 2 A video magnetic tape was prepared in which a 5 micron thick coating layer of cobalt-containing γ-iron oxide was formed on a 25 micron thick polyester stretched film tape, and the following was applied on the magnetic layer of this magnetic tape. A fluororesin aqueous dispersion having the following composition was coated to a dry thickness of about 1 micron.

Fluorine group Tetrafluoroethylene homopolymer 7% Fluorine surfactant 4% Silicone oil 4% Paraffin midpoint solvent 22% Brightener, surfactant, viscosity modifier, stabilizer 11% Water 52% Like this When a magnetic tape with a similar configuration is attached to a portable video tape recorder, the sound quality and image quality deteriorate over a long period of time.
We investigated the battery life and found that compared to when the battery was not coated with an aqueous fluororesin dispersion, the time it took for the audio and video to deteriorate was significantly longer because the magnetic tape was not damaged, and the time it took for the magnetic tape to deteriorate was significantly longer. It has been found that the life of the battery can be extended by around 30% due to smoother operation.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of the magnetic recording medium of the present invention. (1)...Base material, (2)...Magnetic layer, (3)...
Fluorine resin coating layer patent applicant Atsushi Kitamura Patent applicant Nissei Sangyo Co., Ltd. Figure 1

Claims (1)

[Claims] 1. A magnetic recording medium having a structure in which a glossy fiber resin coating layer is provided on a magnetic layer of the magnetic recording medium.