JPH01211218A - Magnetic recording tape - Google Patents

Abstract

PURPOSE:To improve corrosion resistance by providing a coating layer of a volatile rust inhibitor on one face of a magnetic recording tape. CONSTITUTION:The volatile rust inhibitor 5 consisting of dicyclohexylalumin nitrite or diisopropylamine nitrite or the mixture composed thereof or cyclohexylamine carbonate or benzotriazole is superposed on a thin magnetic material film 2 consisting of Co, Co-Ni or Co-Cr alloy. Then, the rust inhibitor passivates the surface of the magnetic metallic film by contact with, adsorption on and bond with said film, by which the corrosion resistance is improved. The surfaces of the volatile rust inhibitive film and the magnetic film are chipped to expose the active surface when the tape travels and comes into high speed sliding contact with a magnetic head and rotary drum, but the volatile rust inhibitor is adsorbed again on such surface and restores the active surface; therefore, the corrosion resistance is assured. This action is executed in a cassette case. The volatile rust inhibitor is filled at all times in the case and since the rust inhibitor has a rapid effect and maintains the effect for a long period of time, the inhibitor is effective for long-term preservation.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording tape made of a metal thin film magnetic material used as a magnetic recording medium for video tape recorders, electronic computers, and the like.

Prior Art The advantages of using a metal thin film as a magnetic material in a magnetic recording tape include that it is advantageous for high-density recording, that a thin and uniform film can be obtained, and that long-time recording is possible.

For this reason, magnetic recording tapes made of thin metal magnetic films have attracted attention in recent years. For example, development is progressing on an 8 mm video magnetic tape in which a thin metal film magnetic material is formed by vacuum deposition on a substrate such as polyethylene terephragm.

Although magnetic recording tapes using this type of metal thin film magnetic material as a recording medium have excellent high-density recording characteristics, their surfaces are susceptible to oxidation and rust in high humidity or corrosive atmospheres.

When this rust occurs, the rust or the magnetic material peels off due to the sliding contact of the magnetic head during recording and reproduction in a video tape recorder. This causes serious problems in practical use, such as increased dropouts, reduced running performance, and reduced main output.

As a means to solve the above-mentioned problem, a magnetic tape made of a thin metal film magnetic material is treated in an oxygen glow or ozone atmosphere to form a stable oxide film layer on the surface of the magnetic tape.
Methods to improve corrosion resistance, methods to improve corrosion resistance by forming a coating with metal oxides that have a corrosion inhibiting effect using sputtering or vacuum evaporation, or methods to improve corrosion resistance by forming a coating with metal oxides that have a corrosion inhibiting effect, or methods to improve corrosion resistance by forming a coating with metal oxides that have a strong corrosion inhibiting effect using plasma or wet methods. There are methods of protection and formation (JP-A-61-22418, JP-A-61-2).
20116, JP 60-57536, JP 5B-189833). Another method is to include a rust preventive agent in the back coat layer provided on the back surface of the base of the magnetic recording tape (Japanese Unexamined Patent Publication No. 58-1
89833) Alternatively, there is a method of attaching a leader tape provided with a rust preventive layer containing a rust preventive agent to only one end of the magnetic recording tape to improve corrosion resistance (Japanese Unexamined Patent Publication No. 62-2
0551 (Publication No. 3).

Problems to be Solved by the Invention However, while it is possible to ensure corrosion resistance over time by modifying and improving the surface of a thin metal film magnetic material, when a magnetic recording tape is run on a video tape recorder, the magnetic head and magnetic head Because the rotating drum on which the tape is mounted slides against the tape surface at high speed, the oxide film layer and protective film layer formed on the surface are removed without being removed, and the corrosion resistance effect does not persist over long periods of use or storage.

In addition, the oxide film layer and the protective film layer made of inorganic material are both highly hard and brittle, so they are easily scratched off, and the chipped powder causes an increase in dropouts or a reduction in the life of the still.

There is still no way to incorporate rust preventive into the back coat layer.
When the magnetic recording tape is wound on a tape reel and installed inside the magnetic tape cassette case, the exposed part of the rust preventive agent contained in the back coat layer becomes uneven on the surface of the magnetic material. On the other hand, since the rust is transferred only to the convex portions, uneven rust prevention treatment is not satisfactory.

Next, in a method in which a leader tape provided with a rust preventive layer containing a rust preventive agent is attached to one end of the magnetic recording tape, the area of the leader tape is approximately 1 for short-time recording compared to the area of the magnetic recording tape. /160. Approximately 1/6 for long-term recording
00, so the rust preventive's lasting effect is extremely short and cannot be considered an effective means for long-term storage.

Means for Solving the Problems In order to solve the above problems, the magnetic recording tape of the present invention has a structure in which at least one surface of the tape has a coating layer of a volatile rust preventive agent.

Effects According to the present invention, the volatile rust preventive agent comes into contact with, adsorbs and bonds with the surface of the metal thin film magnetic material, thereby passivating the surface and improving corrosion resistance.

Furthermore, when running on a video tape recorder, the magnetic head and the rotating drum on which the magnetic head is mounted slide at high speed, and the volatile rust preventive agent and metal thin film magnetic material surface are removed without being exposed, even if the active surface is exposed. Corrosion resistance is ensured by adsorbing and repairing the volatile rust preventive agent again. This action has a relatively high airtightness (because it is carried out inside the cassette case, the case is always filled with a volatile rust preventive agent), it is fast-acting, and its effectiveness lasts for a long time. It is also sufficiently effective in terms of storage and reliability.

As described above, the method of coating at least one surface of the magnetic recording tape with a volatile rust preventive agent is performed by sputtering a volatile rust preventive powder.

Alternatively, the anticorrosive powder may be mixed and dispersed together with a binder resin, an organic solvent, and other necessary components, applied, and dried.

There are various types of volatile rust preventives that can be used, but those that have good volatility and are effective against cobalt, nickel, chromium, etc. are used here.For example, Dicyclohexylamine nitrite, diisopropylamine nitrite, or mixtures thereof, as well as cyclohexylamine carbonate, benzotriacetate, etc., are preferably used. The thickness of at least one coating should be between 0.01 and 0.1 microns, because if it is thicker than 0.1 micron, the amount of adhesion to the surface of the magnetic head will increase, causing disturbances in reproduced images and poor running.
．． A range of 1 cyclon is preferred, and 0.02 to 0.05 micron is more preferred.

Example Next, the present invention will be explained using an example.

FIGS. 1A to 1C are cross-sectional views of an 8 mm width magnetic recording tape according to embodiments A to C of the present invention.

In each of Examples A to C, a metal thin film magnetic material 2 made of a cobalt-nickel alloy with a thickness of 0.1 to 0.2 microns is coated on the surface of a polyethylene terephthalate base film (hereinafter referred to as the base film) 1 with a thickness of about 10 microns. A back coat layer 3 consisting of a resin binder, carbon particles and an inorganic filler was further applied to a thickness of 0.3 to 0.5 microns on the back side of the base film 1 by a wet method.

Thereafter, it was cut into a predetermined width to produce a magnetic recording tape. In this magnetic recording tape, Example A is applied to the surface of the back coat layer 3, Example B is applied to the cut surfaces 4a and 4b of the magnetic recording tape on the side surfaces perpendicular to the tape surface, and Example C is applied to the metal thin film magnetic body 2. A vaporizable rust preventive agent layer 5, which is a coating layer, was formed on each surface by sputtering dicyclohexylamine nightquina crystal powder. In addition, the coating thickness was 0.05 micron for Examples A and B, and 0.02 micron for Example C, taking into account the reduction in output due to spacing loss.
Micron.

Next, a magnetic recording tape 1o having the configuration of Examples A to C was prepared.
A video tape cassette was produced by winding an O meter into a cheaply y shape and placing it inside a cassette case. This tape set was loaded into a videotape recorder and continuously run 100 passes in playback mode.

After that, remove the tape and place it in a high temperature and high humidity environment (30°C, 80°C).
%R, H) for 48 hours, changes in cobalt hydroxide on the surface of the magnetic tape were measured by photoelectron spectroscopy (ESCA). ``This cycle was repeated 10 times.

As a comparative example, monocarboxylic acid (R-CH-COOH), known as an organic rust preventive agent, was mixed and dispersed in isopropyl alcohol to a concentration of 1,500 ppm, and a solution was prepared using a magic trick to form a magnetic material for a magnetic recording tape. Comparative Example P is a magnetic recording tape having a rust preventive layer with a thickness of about 0.02 microns on the surface, and in this magnetic recording tape,
Comparative Example Q was one that was not run using a video tape recorder.

FIG. 2 is a plot of the main peak of cobalt, which is the main component of the magnetic material, and the peak ratio of surface hydroxide in ESCA. The video magnetic recording tapes (Examples A to C) in which the vaporizable rust preventive layer 5 was provided on at least one surface of the magnetic recording tape had a higher level of hydroxyl oxidation on the surface of the magnetic material than Comparative Example P treated with the conventional example. There is little increase in quantity.

This was at almost the same level as Comparative Example Q, which was treated using the conventional method and was not repeatedly run on a video tape recorder, indicating that the rust-preventing effect of the volatile rust preventive agent lasts for a long time. That is, in Comparative Example P treated with the conventional example, during continuous running in a video tape recorder, the rust-preventive layer coated on the surface is gradually scraped off by the magnetic head and the rotating drum on which the magnetic head is mounted, and the rust-preventive layer is removed. This means that the antirust effect of the agent has been lost. On the other hand, in Examples A to C in which the vaporizable rust preventive layer 5 was provided on at least one surface of the tape, the magnetic head was continuously run by a video tape recorder, and the magnetic material was surfaced by a rotating drum on which the magnetic head was mounted. The rust preventive agent adsorbed to the surface is scraped off.
Even if the active surface of the magnetic material is exposed, the rust preventive component that volatilized on this part is immediately adsorbed to the surface, repairing and protecting it, thereby ensuring the long-term storage reliability of the magnetic recording tape.

In addition, the magnetic recording tape processed in the conventional example (Comparative Example P)
After 3 cycles, there was an increase in dropouts, and after 6 cycles, it became impossible to run on a video tape recorder. On the other hand, it was confirmed that the various magnetic recording tapes obtained according to Examples A to C of the present invention had no problems with regard to dropout, output, and runnability.

Note that the metal thin film magnetic body 2 may be made of cobalt or a cobalt-chromium alloy. In addition to the crystal powder used in this example, the crystal powder forming the volatile rust preventive layer 5 by sputtering may be diisopropyfuramine nitrite, a mixture of synchrohexylamine nitride and diimpropylamine nitride, or cyclohexylamine nitride. 1 Rareamine carbonate, benzotriazole, etc. may also be used.

Effects of the Invention As is clear from the above explanation, in the magnetic recording tape of the present invention, the volatile rust preventive agent comes into contact with, adsorbs and bonds with the surface of the metal thin film magnetic material, thereby passivating the surface and improving corrosion resistance. It is something.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a magnetic recording tape in each of Examples A to C of the present invention, and FIG. 2 is a peak ratio of cobalt main beak and surface hydroxide after each cycle of ESCA in Examples A to C. FIG. DESCRIPTION OF SYMBOLS 1...Polyethylene terephthalate base film, 2...Metal thin film magnetic material, 3...Nokutsu coat layer, 4a, 4b...Magnetic recording tape cut surface , 6... Volatile rust preventive agent layer. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 - Cycle

Claims (3)

[Claims] (1) A magnetic recording tape consisting of a magnetic thin film of metal provided on a substrate by vacuum deposition, characterized in that a volatile anticorrosion layer is formed on at least one surface of the tape. (2) The metal thin film magnetic material is made of cobalt, cobalt-nickel, or cobalt-chromium alloy, and the volatile rust preventive layer is dicyclohexylamine nitrite, diylipropylamine nitrite, a mixture thereof, or cyclohexylamine carbonate. 2. The magnetic recording tape according to claim 1, comprising benzotriazole. (3) The magnetic recording tape according to claim 1, wherein the volatile anticorrosion layer is formed on a side surface perpendicular to the surface of the tape.