JPS5813444Y2 - magnetic recording tape - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a magnetic recording tape that runs stably during winding and can be wound up with side end surfaces neatly aligned.

With magnetic recording tapes, which have a magnetic layer on the surface of a plastic base film such as polyester film or acetate film, during high-speed operations such as fast forwarding or rewinding, there may be problems due to interlayer adhesion between the tapes or air being trapped between the tapes. The running becomes unstable, and the side end surfaces of the tape wound on the take-up reel are not aligned in an orderly manner, resulting in what is called a disorderly winding state.

As a result, the side edges of the magnetic recording tape are stretched, deformed, or damaged, causing output fluctuations and dropouts.

As a method to improve such defects, a groove portion with a width of about 0.4 rran and a side length of about 1.0 rran is formed on the surface opposite to the magnetic layer of the plastic base film, communicating at the side edge 1.
A protrusion-patterned coating consisting of square protrusions with a flat surface of 25mm is applied to a thickness of approximately 1-2μ to prevent irregular winding by smoothing the outflow of air caught between the tapes. It is proposed to do so.

However, in recent years, with magnetic recording tapes in which the surface of the magnetic layer has been made smooth with a calender roll or the like to improve contact with the magnetic head, it is not possible to sufficiently suppress irregular winding even if the above conventional method is used. .

Moreover, when the coating film is stored as a wound tape for a long period of time, it has the disadvantage that it adheres to the magnetic layer and peels off.

In order to improve this drawback, the present inventors investigated various methods and found that the surface opposite to the magnetic layer of a plastic base film such as a polyester film or acetate film was coated with sandblasting or etching in an alkaline solution. by mechanical or chemical means,
It has been found that when a flexible rough surface with fine protrusions is formed, the irregular winding state can be sufficiently suppressed.

However, since the rough surface of this magnetic recording tape has a relatively large electrical resistance, it is easily charged, and depending on the usage conditions,
Charging may cause random winding.

The present invention was devised in view of the above circumstances, and by applying a small amount of antistatic agent to the rough surface formed on the surface opposite to the surface on which the magnetic layer of the plastic base film is formed, It maintains excellent antistatic properties for a long period of time without impairing the smooth outflow of air trapped between the tapes due to the fine protrusions of the tape and the suppression of slippage between the tapes, resulting in good tape winding. It was designed so that it was possible to carry out the acquisition.

In order to enable such excellent tape winding,
It is necessary to appropriately select the roughness of the rough surface, and it is preferable that the center line average roughness of the rough surface is in the range of 0.3 to 5μ, and in order to maintain this roughness and flexibility, antistatic The key is to apply the agent.

One method to satisfy this requirement is to dissolve or disperse the antistatic agent in a solvent such as water, alcohol, toluene, MIBK, etc. at a sufficiently low concentration, and apply this on the rough surface, or to apply the antistatic agent to the rough surface. By immersing a substrate film having a rough surface therein, the antistatic agent can be thinly and uniformly deposited on the rough surface.

In order to coat the antistatic agent without impairing the roughness and flexibility of the rough surface, it is preferable to use a liquid in which the antistatic agent is dissolved or dispersed at a concentration of 10% by weight or less.

In addition, a polymerizable antistatic agent is used as an antistatic agent,
When this is cured and deposited on the rough surface of the base film, it is possible to more effectively prevent the antistatic agent from disappearing from the rough surface, and moreover, it can prevent the antistatic agent from oozing out onto the surface and causing adhesion. This is more preferable because it can also prevent this.

As a polymerizable antistatic agent, polymerizable No. 4 manufactured by Yoshimura Oil Chemical Co., Ltd.
PM-70゜AW-1, AW consisting of class ammonium salt
-2, Vermax S, PMX-5006, PMX50
07, PMX5008, etc. are suitable.

These antistatic agents contain a polymerization initiator, so
Polymerization can be easily carried out by heat treatment at 00 to 120°C.

Next, embodiments of the present invention will be described.

Example 1 As shown in the drawings, a rough surface 1 having soft and fine protrusions was formed on the back surface by sandblasting.
A magnetic paint having the following composition was applied to a thickness of about 12 μm on the surface of a polyester base film 20 having a thickness of 5 μm to form a magnetic layer 3, and the surface was given a mirror finish using a calendar roll.

Magnetic paint composition 7-Fe2O3 powder 300 parts by weight Vinyl chloride vinyl acetate copolymer 80 DOP 30 /1 Toluene
150 〃 MIBK 200 tt Next, on the rough surface 1 of this base film 2, a mixed solution of 2MX5006 (manufactured by Yoshimura Yukagaku, polymerizable quaternary ammonium salt antistatic agent) in toluene and MIBK was applied and dried. Then, heat curing treatment is performed at 100 to 120°C for 10 minutes, and antistatic agent 4 is added to about 0.5? /lr? It was covered with

Rank the center line average roughness of the rough surface of this base film,
As a result of measurement using a stylus type electric surface roughness meter manufactured by Tyler Hoven, it is approximately 0.8μ.

Example 2 A polyester film having a thickness of about 25 μm was etched with a caustic soda solution to form a soft, rough surface with fine protrusions as the base film. Example 1
A magnetic layer similar to the above was applied to one side.

Next, PM is applied to the rough surface of the base film opposite to the magnetic layer.
-70 (manufactured by Yoshimura Yukagaku, polymerizable quaternary ammonium salt antistatic agent) was applied and dried.
A heat curing treatment was performed at ~120°C for 10 minutes, and an antistatic agent was applied at approximately 0.5y71rrt'.

The center line average roughness of the rough surface of this base film is about 1.
It is 5μ.

Next, for comparative reference, a magnetic layer similar to that in Example 1 was applied to the surface of a polyester film that had not been roughened, and a groove approximately 0.4 mm wide was added to the back surface. A magnetic recording tape (conventional example) in which a coating film with a protrusion pattern consisting of a square protrusion with a flat surface with a side length of about 1.0 mm is applied with a paint made of vinyl chloride-vinyl acetate copolymer. was created.

As described above, the magnetic recording tapes obtained in Examples 1 and 2, the button of the conventional example, and the untreated antistatic one (comparative example) of Example 1 were wound at a speed of about 7 m/see. The table below shows the results of repeating the loading operation, measuring the number of times at which the irregular winding state was observed and the time (half-life) until the charging voltage was halved after charging at a predetermined voltage.

As is clear from the above table, the magnetic recording tape according to the present invention can be wound smoothly even after being wound more than 150 times, with good winding. The amount is significantly reduced compared to the Examples and Comparative Examples, and winding can be carried out smoothly even in a dry state.

In addition, the magnetic recording tape according to the present invention has flexibility or pliability because the protrusions on the rough surface are formed of a plastic material, and can moderately suppress slippage between the tapes.
It prevents traces from remaining on the magnetic layer, and exhibits excellent characteristics with almost no abnormality observed in output fluctuations due to traces on the magnetic layer.

[Brief explanation of the drawing]

The drawing is a sectional view of an embodiment of a magnetic recording tape according to the present invention. 1...Rough surface, 2...Base film, 3
...Magnetic layer, 4...Charging cutoff agent.

Claims (1)

[Scope of utility model registration request] A flexible rough surface with fine protrusions is formed on the back surface of a plastic base film with a magnetic layer on the surface by mechanical or chemical means, and the center line average roughness of the rough surface is 0.3 to 5 μm. A magnetic recording tape characterized in that the rough surface is coated with a polymerizable antistatic agent.