JPS5928235A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To provide a magnetic recording medium capable of stable recording in high speed operation without causing irregular winding, and high density recording and reproducing, by incorporating at least 0.1-20wt% TiO and 0.1- 5wt% antistatic agent based on the quantity of ferromagnetic powder in a magnetic layer. CONSTITUTION:A mixture of 100pts.wt. Co-contg. gamma-Fe2O3, 10pts.wt. vinyl chloride-vinyl acetate-vinyl alcohol copolymer, 10pts.wt. polyurethane resin, 2pts.wt. lubricant, 10pts.wt. abrasives, 2pts.wt. alkylamine deiv. ''TB 103'' manufactured by MATSUMOTO YUSHI KK, and 5pts.wt. TiO powder having 0.015-5mum average particle diameter is intermixed and dispersed in a sand mill, a prescribed amt. of polyisocyanate hardening agent is added to it, and a magnetic tape is obtained by coating with this dispersion. On the other hand, a magnetic tape was prepd. by using 5pts.wt. TB 103 without adding said TiO powder, and compared with said tape. As a result, since the former contains the TiO powder and the antistatic agent in the magnetic layer, the magnetic tape was found to have a winding appearance remarkably improved by their synergistic effect.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording medium, in which titanium monoxide is contained in a magnetic layer in an amount of 0.1 to 20% by weight based on ferromagnetic powder;
By containing at least the anti-static agent in the 5-weight mooring part, it exhibits excellent runnability without winding disorder during high-speed operations such as fast-forward shuttle search in a recording/reproducing device such as a video tape recorder, and is free from dropouts. It is an object of the present invention to provide a magnetic recording medium that does not cause such problems and can perform high-density recording and reproduction.

γ-Fe = 03, a magnetic recording medium such as a magnetic tape obtained by applying a magnetic paint containing a ferromagnetic powder such as CO-containing γ-Fe203, a binder, etc. onto a support such as a polyester film. Because the magnetic layer coating has high electrical resistance, it is easily charged with static electricity.
Therefore, dirt, dust, etc. tend to stick to the magnetic tape, causing dropouts, and furthermore, the winding and running properties of the magnetic tape become poor.

In order to eliminate such drawbacks, carbon black, a surfactant, etc. are conventionally added to the magnetic layer to prevent static electricity. However, in order to obtain a sufficient antistatic effect with these substances, a considerably large amount must be added. As a result, even if antistatic properties are achieved, the packing density of the magnetic powder decreases, and the electromagnetic conversion characteristics deteriorate. This is not so desirable. Furthermore, if a large amount of surfactant is contained, plumping will occur, and the surface electrical resistance of the magnetic layer will be greatly affected by humidity, resulting in a significantly large surface electrical resistance in a dry state.

The present invention eliminates the above-mentioned drawbacks; that is, when the magnetic layer contains not only an antistatic agent but also rice-based titanium, the blooming phenomenon that occurs when only an antistatic agent is used is suppressed. It has been discovered that the rotating drum, magnetic head, etc. are less likely to get dirty, and that the winding shape and running properties of the magnetic tape are also improved, and this invention was developed based on these viewpoints.

Examples of the magnetic recording medium according to the present invention will be described below.

Example 1 100 parts by weight of 0o-containing γ-Fe203, 10 parts by weight of vinyl chloride-vinyl acetate-vinyl alcohol copolymer, 10 parts by weight of polyurethane resin, 2 parts by weight of lubricant, 10 parts by weight of abrasive
Parts by weight, 2 parts by weight of an alkylamine derivative (TE101, Matsumoto Oil Film), and 5 parts by weight of TiO powder with an average particle size of 0.015 to 5 μm were mixed and dispersed in a sand mill, and an incyanate curing agent was added to the mixture. A magnetic paint containing a predetermined amount of is applied to a base such as, for example, a polyester film, subjected to calendering, a curing reaction is performed, and is slit to a predetermined width to obtain a magnetic tape.

Example 2 Using a cationic surfactant (AMS937, manufactured by Lion Oil) in place of TE101 in the magnetic paint of Example 1,
A magnetic tape is obtained in the same manner as in Example 1.

Example 3 A magnetic tape is obtained in the same manner as in Example 1 except that a cationic surfactant (Rheostat 937, manufactured by Lion Oil Co., Ltd.) is used in place of TBl and 03 in the magnetic paint of Example 1.

Comparative Example 1 A magnetic tape is obtained in the same manner as in Example 1 except that 5 parts by weight of TE101 is used without adding TiO powder to the magnetic coating material.

Comparative Example 2 A magnetic tape is obtained in the same manner as in Example 2 except that 5 parts by weight of AMS937 is used without adding TiO powder to the magnetic paint.

Comparative Example 3 A magnetic tape is obtained in the same manner as in Example 3 except that 5 parts by weight of Rheostat 937 is used without adding TiO powder to the magnetic paint.

Comparative Example 4 A magnetic tape is obtained in the same manner as in Example 1, except that TE101 is not added to the magnetic coating material.

Comparative Example 5 A magnetic tape is obtained in the same manner as in Example 1 except that 2 parts by weight of carbon black is added to the magnetic paint without adding TE101.

The magnetic tape obtained as described above was mounted on a video tape recorder, and a repeated running test was conducted 100 times.The cumulative defective rate of the magnetic tape in the winding form was determined to be 0% for those of Examples 1 and 3. , that of Example 2 is 1% or less,
Comparative Example 1 is 25%, Comparative Example 2 is 28%, Comparative Example 3 is 32%, Comparative Example 4 is 6%, Comparative Example 5 is 4%, etc. Comparing the magnetic tape of this example and the magnetic tape of the comparative example, T
When both the TiO powder and the antistatic agent are mixed together in the magnetic layer, the winding appearance of the magnetic tape is extremely good, and when the TiO powder is not included in the magnetic layer, the magnetic tape is The winding appearance of the magnetic tape is extremely poor, and even if TiO powder is included in the magnetic layer, if the antistatic agent is not included, the winding appearance of the magnetic tape is not good. It can be seen that the synergistic effect of these significantly improves the winding appearance of the magnetic tape.

Similarly, such a magnetic tape is wound with an average grain size of 0.01 to 5 μm, preferably 0.015 μm, in the magnetic layer.
~2μm titanium powder is 0.1~2μm compared to magnetic powder
0 weight ratio, antistatic agent is 0.5 to 5 to magnetic powder
If it is contained in a proportion by weight, the result is extremely good.

Similarly, in the above example, TB 1 was used as the antistatic agent.
03, AMS937, and Rheostat 937, but there are also others, such as amine salts, alkyl ester types, alkyl ether types, alkyl sulfonates, alkyl phosphates, quaternary ammonium salts, sorbitan derivatives, hetain types, and imidacillin types. An antistatic agent may also be used.

Furthermore, when the surface electrical resistance (Ω) of the magnetic tape obtained above was measured, it was found that the magnetic tape of Example 1 was 5×10 7
, 8×107 for Example 2, 7× for Example 3
107, Comparative Example 1 is 2 x 109, Comparative Example 2 is 3 x 109, Comparative Example 3 is 3 x 109, Comparative Example 4
The magnetic tape of Comparative Example 5 has a size of 1×108, and the magnetic tape of Comparative Example 5 has a size of 9×107.The magnetic tape of this example also has an excellent antistatic effect, and is free from static electricity and dirt and dust. It is also difficult.

Same, the surface electrical resistance of the magnetic layer is 9.9X109Ω/crn
The following materials are sufficient to prevent static electricity, and dirt, dust, etc. are difficult to adhere to.

As described above, the magnetic recording medium according to the present invention contains, in the magnetic layer, Ookkibe titanium in an amount of 0.1 to 20% by weight relative to the ferromagnetic powder in the magnetic layer, and an antistatic agent of 0.1 to 5% by weight. For example, in a recording/reproducing device such as a video tape recorder, it exhibits excellent running performance without winding disorder during high-speed operations such as fast forward shuttle search, does not cause dropouts, and is free from dirt and dust. It has the advantage of being difficult to adhere to, and furthermore, the packing density of the magnetic powder can be increased, so that the electromagnetic conversion characteristics can be improved.

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Claims (1)

[Claims] In the magnetic layer, 0.1 to 20% of the ferromagnetic powder in the magnetic layer.
A magnetic recording medium comprising at least 0.1 to 5% by weight of titanium monoxide and 0.1 to 5% by weight of an antistatic agent.