JPS60140530A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To prevent a substrate from curling and wrinkling by providing a magnetic layer on one surface of a substrate and a back layer on the other surface and incorporating anatase TiO2 particles in the back layer. CONSTITUTION:A magnetic layer is formed on one surface of a substrate by sticking a ferromagnetic metal thereto or coating iron oxide together with a binder thereto. A back layer is provided on the other surface of the substrate. The back layer is formed by coating the anatase TiO2 particles mixed together with a solid material such as carbon black, graphite, molybdenum disulfide, etc. and a lubricant such as fatty acid, surface active agent, etc. with a binder such as cellulosic resin, polyvinyl butyral resin, polystyrene resin, etc. on the substrate. The mechanical strength is improved by such layer, by which curling and wrinkling are prevented and running property, winding property, drop-out, etc. are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording medium having a back layer.

When a magnetic layer is formed on a thin substrate such as a polymer film, curls may occur at both ends of the substrate in the direction perpendicular to the strike direction.
It has the disadvantage that wrinkles tend to form on the entire surface. When curls occur at both ends of the substrate, running performance, winding performance, and pet touch deteriorate, and when wrinkles occur, dropouts and output fluctuations occur.

Therefore, preventing curls and wrinkles on the substrate has become an important technical issue for magnetic recording media.

The object of the present invention is to improve the above-mentioned drawbacks and to provide a magnetic recording medium that prevents curls and wrinkles of the substrate.

In order to achieve the above object, the present invention provides a magnetic recording medium in which a magnetic layer is provided on one surface of a substrate and a back layer is provided on the other surface, in which the back layer contains anatase-type TiO2.
The present invention provides a magnetic recording medium characterized by containing two particles.

Hereinafter, the present invention will be explained based on examples.

As the substrate, a polymer film such as polyester or polypropylene having a thickness of about 10 μm is used.

Then, a ferromagnetic metal made of iron, cobalt, nickel, or an alloy of these is attached to one surface of this substrate by vacuum evaporation, ion blasting, sputtering, plating, etc., or iron oxide is coated with a binder. Then, a magnetic layer is formed. A back layer is provided on the other side of the base. The back layer consists of anatase-type TiO resin, epoxy resin, vinyl resin, silicone resin, polyurethane resin,
It is formed by applying a mixture of a binder such as polymethyl methacrylate resin, acrylonitrile-butadiene-styrene copolymer resin, or polystyrene resin.

The anatase-type lower 10□ particles have the shape of a square plate or a flat quadrangular bipyramid developed in a direction parallel to the <001) plane, and according to the present invention, such particles are included. Therefore, the mechanical strength is increased and the occurrence of curls and wrinkles on the substrate is prevented.

Note that the former square plate shape developed in a direction parallel to the (001) plane is more effective.

For example, when running properties, single winding properties, dropout, and composite Young's modulus were measured for the examples of the present invention and the conventional examples, the results shown in the table were obtained.

A polyester film with a thickness of 10 .mu.m and a width of 1"/2 inch is used as the substrate. The magnetic layer is CO:N+=8:2
A ferromagnetic metal having a ratio of 0.1 μm is formed on one surface of the substrate by vacuum evaporation to a thickness of 0.1 μm and l−1c=Boo (Oe). The back layer was made of 1 part of fluorosurfactant, 50 parts of MEKl, and 150 parts of toluene in the conventional example.
The present invention is formed by coating the other surface of the substrate with a coating material mixed in a binder of 10 parts of nylic chloride-vinyl acetate co-polymerized resin to a thickness of 1 μm. It is formed by applying paint mixed with

As is clear from the results in the table, in the present invention, the composite Young's modulus is approximately twice that of the conventional product, the mechanical strength is increased, and the running performance, winding performance, and dropout are improved.

As described above, according to the present invention, a magnetic recording medium can be obtained that can prevent curls and wrinkles by improving mechanical strength, and can improve running performance, winding performance, dropout, etc.

Patent applicant: Hitachi Capacitor Co., Ltd.

Claims (2)

[Claims] (1) A magnetic recording medium in which a magnetic layer is provided on one surface of a substrate and a back layer is provided on a narrow surface, characterized in that the back layer contains anatase type T+O particles. (2) Anatase type T+O, in which the particles are in the form of a square plate developed in a direction parallel to the (001) plane.Claim 1
Magnetic recording medium described in Section 1.