JPS58208931A - Manufacture of magnetic tape - Google Patents

Abstract

PURPOSE:To thin a magnetic layer, also to raise an S/N ratio, and to increase the contact strength of a base material and the magnetic layer, by raising the surface density of magnetic particles by applying a magnetic field when solidifying a mixed composite which adds magnetic material fine particles in synthetic resin. CONSTITUTION:When applying and solidifying a composite which disperses magnetic material fine particles 3 in synthetic resin 5, on the surface of a synthetic resin tape 2, a layer 4 which raises density of the magnetic material fine particles 3 by applying a magnetic field in the thickness direction of the tape by a magnetic pole 6 is formed. In this regard, it is desirable that ultrasonic vibration is outputted together with the magnetic field so that the particles 3 move easily. In this way, density of the particles 3 in the layer 4 is made about two times or more as high as the inside of a resin layer 5 of the lower layer, S/N ratio is raised about 50% comparing with conventional S/N ratio, and thickness of a magnetic layer (total of the layers 4, 5) can be set to <=1mu. In this way, strength of the tape itself and adhesive strength of the magnetic layer and the tape 2 are raised and the durability is also raised.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a magnetic tape in which a magnetic field is applied during solidification to create a difference in concentration distribution of magnetic particles in a synthetic resin tape.

The conventional magnetic tape in the United States is a tape made of polyester resin, polyimide resin, acetyl cellulose resin, etc. as a base material, and a powdered magnet is fixed to the surface of the tape. Commonly used magnets include platinum-cobalt-based, rare-earth cobalt-based, aFezes-cobalt-rare-earth based magnets, which are made into fine particles and bonded together. However, the thickness of the magnetic particle layer obtained by coating on the base tape could not be reduced by any method, and the noise level could not be improved.

8 In view of these current circumstances, the present invention incorporates magnetic fine particles into a base synthetic resin, applies a magnetic field in the thickness direction (vertical direction) during solidification, increases the surface density of the magnetic particles, and solidifies to form a tape shape. This is used to form an ultra-thin surface magnetic layer to increase the noise ratio and create a highly sensitive tape.
At the same time, it is possible to increase the adhesion force of the magnetic material and increase the strength of the tape.

Next, the present invention will be explained by way of an example.

First, Figure 1 explains the conventional magnetic tape.
A magnetic layer 1 is formed by adhering a magnetic powder 3 to the surface of a synthetic resin tape 2, but the thickness of such an adhesive layer 1 is limited even when the type of magnetic powder 3 is considered. Normally at least 5
~lOμ.

FIG. 2 shows an embodiment of the present invention, in which a powder magnetic material 3 is mixed with a synthetic resin 2 of a tape forming material. Then, when molding and solidifying the synthetic resin into a thin film tape, the magnetic poles 6 are opposed to the surface and scanned over the surface to treat the magnetic particles 3 in the resin so as to create a difference in concentration distribution between the surface and the inside, and solidify the resin. . By performing such a solidification process, an extremely thin magnetic layer 4 in which magnetic powder 3 is densely distributed is formed on the surface layer of the molded tape, and the inside is dotted with magnetic powder 3. A thick layer 5 can be formed.

Generally, tape resins include polyester resin, polyimide resin, acetyl cellulose resin, and -t.

Other materials can be used, and high Hc magnetic powders such as rare earth balt, platinum cobalt, α-Fe203, and Co-Ni can be used as the magnetic material.

In the present invention, a mixed composition containing γFe z Oa in the amount shown in Table 1 was made into a tape and solidified, and a magnetic field of 500 Gauss was applied during solidification. Furthermore, by outputting ultrasonic vibrations, for example, 32 kHz f, it is possible to easily move the powder (
When the Noshi Tape surface concentration is processed to a high density, the surface IIk degree of the magnetic powder is approximately twice that of the inside, and the surface layer 4
The thickness of the lower layer 5 was 0.5μ and the thickness of the lower layer 5 was 50μ. The signal-to-noise ratio was improved by about 50% compared to the conventional one.

Table 1 - Example of γFe2O3 Mixed Composition When a coarse magnetic film is formed, the magnetic powder 3, which is also mixed in the lower layer 5, is dispersed and distributed within the resin, resulting in a dispersion-strengthened structure. Compared to a polyester film made in the United States with a magnetic particle layer adhered to it, the strength is approximately 1
An improvement of about 3%. As explained above, Fu%mei is made by applying a magnetic field and applying ultrasonic vibration when fine particles of magnetic material are put on a synthetic resin material and solidified into a tape shape. w: J meeting, within the surface of the tape! −
There is a difference in the quality of the magnetic material between the two.

It is not easy to form a magnetic layer with a thickness of 1 .mu.m or less in the process of forming a magnetic layer with high density and high density on the surface layer.

Thus, +: The magnetic tape of the invention is designed to reduce the noise density and increase the S/N ratio, and also to increase the strength of the tape itself by strengthening the dispersion of the powder, as well as the adhesion holding power of the magnetic fine particles. It has increased durability and wear resistance, and is extremely effective when used.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a conventional magnetic tape, and FIG. 2 is a cross-sectional view of an embodiment of the invention. 1...Magnetic layer 3...Magnetic grains 2...Synthetic resin tape 4...High-density magnetic layer 5...Synthetic resin layer 6 - Magnetic pole patent applicant Bengami Japax Laboratory Co., Ltd. Agent Person Masu Burier Ko West - Ward 7rIA 3 Taku 2 Diagram

Claims (1)

[Claims] 1. A mixed composition in which fine particles of magnetic material are added to a synthetic resin material is molded into a tape of a predetermined thickness, and when it is solidified, a magnetic field is applied thereto to form a surface layer within the tape. A method for producing a magnetic tape characterized by increasing the concentration of magnetic crystalline particles. 2. The method for producing a magnetic tape according to claim 1, characterized in that fine particles of γFezOa are mixed with nitrocellulose, polyvinyl butyral, and 7-chlorohexane as the magnetic material, and ultrasonic vibration is performed in a magnetic field.