JPS5939812B2 - magnetic recording medium - Google Patents

Description

Detailed Description of the Invention The present invention relates to a magnetic recording medium, in which a quaternary ammonium salt represented by the general formula +R1-<R3 is coated on the surface of the magnetic recording medium or between the magnetic layer and the base layer. As a result, it is possible to effectively prevent static electricity on the magnetic recording medium, to improve the running properties and winding shape of the magnetic tape, and in particular, to effectively reduce the charging voltage, making it difficult to generate discharge noise. The object of the present invention is to provide a magnetic recording medium that is easy to manufacture and inexpensive.

Conventionally, magnetic tapes and the like have, for example, a polyester film on which a magnetic layer made of a mixture of magnetic powder, a binder, and various other additives is formed.

All of these magnetic tapes are mainly insulating, and since magnetic powder has high electrical resistance,
Magnetic tape has a high electrical resistance, and magnetic tape is extremely easily charged with static electricity due to friction, etc., and dust and the like are easily attached to the magnetic tape. This also results in an increase in the coefficient of static friction,
This disturbs the winding shape of the magnetic tape and further reduces running performance. In order to eliminate this drawback, conventionally, a highly conductive material such as carbon is placed in the magnetic layer to lower its electrical resistance and prevent the charging phenomenon from occurring. Alternatively, instead of carbon, anionic, cationic, nonionic, or amphoteric surfactants have been added. However, these antistatic agents have the disadvantage that they cause a decrease in the magnetic flux density and sensitivity of the magnetic recording medium.Recently, quaternary ammonium salts are said to be effective in preventing static electricity. However, when such quaternary ammonium salts are added to the magnetic layer, the disadvantage is that once the magnetic tape becomes statically charged due to friction, the static electricity is difficult to discharge. . In addition, the charged voltage is high, which also has the disadvantage of causing discharge noise. The present invention eliminates the above-mentioned drawbacks, and examples thereof will be described below.

Example 1 About 100 parts by weight of Co-γFe2O3, about 19 parts by weight of a mixture of vinyl chloride-vinyl acetate-vinyl alcohol copolymer and polyurethane elastomer, about 5 parts by weight of carbon,
Approximately 1 part by weight of soybean lecithin, approximately 1 part by weight of a mixture of 2:1 hexyldecyl stearate: 2:2 hexyldecyl palmitate and 2:1 isoamyl stearate: isoamyl palmitate, a mixture of methyl ethyl ketone, toluene, and methyl isobutyl ketone. After mixing and dispersing a paint containing about 270 parts by weight of a solvent for about 20 hours, a polyisocyanate containing about 1 part by weight of 2-ethylhexyl acid phosphate (for example, D-103H from Takeda Pharmaceutical Co., Ltd.) is mixed and dispersed.
After adding about 8 parts by weight of this magnetic paint onto a polyester film and calendering it, a solution of about 0.5% methanol and toluene of a quaternary ammonium salt of was uniformly applied to the surface of the magnetic layer to give a sufficient amount of water. After drying to a temperature of about 50° C., the tape is heat-treated at about 55° C. for about 24 hours and slit into a predetermined width to produce, for example, a magnetic tape for a video tape recorder.

Example 2 A magnetic tape is produced in the same manner as in Example 1, using a substitute for the quaternary ammonium salt in Example 1.

Example 3 A magnetic tape was prepared in the same manner as in Example 1, using instead of the quaternary ammonium salt in Example 1.

Example 4 A magnetic tape was prepared in the same manner as in Example 1, using instead of the quaternary ammonium salt in Example 1.

Example 5 A magnetic tape was prepared in the same manner as in Example 1, using instead of the quaternary ammonium salt in Example 1.

Example 6 A magnetic paint having the same composition as in Example 1 was applied to a polyester film, and after calendering, about 5
The magnetic tape was heat-treated at 5°C for about 24 hours, and then the quaternary ammonium salt solution of Example 1 was applied to the polyester film side of the magnetic tape, and after sufficiently drying, it was slit into a predetermined width and magnetically coated. make tape.

Examples 7 to 10 Magnetic tapes are produced in the same manner as in Example 6 using the quaternary ammonium salts of Examples 2 to 5.

Example 11 The quaternary ammonium salt solution of Example 1 was applied and dried on a polyester film, and then the magnetic paint of Example 1 was applied thereon, and after calendering, it was heated at about 55°C for about 24 hours.
The tape is heated for a period of time and then slit to a predetermined width to make magnetic tape.

Examples 12-15 Magnetic tapes are made in the same manner as in Example 11 using the quaternary ammonium salts of Examples 2-5.

Comparative Example 1 A magnetic tape is produced in the same manner as in Example 1, using the quaternary ammonium salt in place of the quaternary ammonium salt in Example 1.

Comparative Example 2 A magnetic tape is produced in the same manner as in Example 6, using the quaternary ammonium salt of Comparative Example 1 instead of the quaternary ammonium salt of Example 6.

Comparative Example 3 A magnetic tape is produced in the same manner as in Example 11, using the quaternary ammonium salt of Comparative Example 1 instead of the quaternary ammonium salt in Example 11.

Comparative Example 4 A magnetic tape is prepared in which the quaternary ammonium salt of Comparative Example 1 is mixed into the magnetic layer.

Comparative Example 5 A magnetic tape is prepared by mixing the quaternary ammonium salt of Comparative Example 1 into a polyester film.

Comparative Example 6 Magnetic tapes were prepared in which the quaternary ammonium salts of Examples 1 to 5 were mixed into the magnetic layer.

Comparative Example 7 Magnetic tapes were prepared in which the quaternary ammonium salts of Examples 1 to 5 were mixed into a polyester film.

Comparative Example 8 A magnetic tape is made by coating a magnetic paint on a polyester film that does not use any quaternary ammonium salt.

Regarding the magnetic tape made in the above example, the antistatic effect,
The running conditions and static friction coefficient were measured as shown in the table.

As is clear from this table, there is not much difference between the initial μs and the μs after 50 repetitions of the magnetic tape made according to this example, and the charging phenomenon is caused by friction. In contrast, in the case of the magnetic tapes of Comparative Examples 1 to 5, there was a large difference between the initial μs and the μs after 50 repetitions, indicating that a significant charging phenomenon occurred due to friction. It can be seen that

In particular, when the quaternary ammonium salt according to the present invention is coated on the base opposite to the magnetic layer, the antistatic properties are better than when the same quaternary ammonium salt is mixed in the magnetic layer or the base. The effect is extremely good. Also, regarding the charged voltage, when the quaternary ammonium salt according to the present invention is applied to the surface of the magnetic recording medium, it becomes smaller than when it is mixed in the magnetic layer or the base, and the discharge noise is reduced accordingly. is less likely to occur. On the other hand, the fourth
When a grade ammonium salt is mixed into the magnetic layer or base, the charged voltage is lower, and discharge noise is less likely to occur. Also, regarding the running properties of the magnetic tape, the magnetic tape made according to this example has good performance, and for example, there is no deterioration of the winding shape such as loosening during winding of the magnetic tape. In the case of the magnetic tape such as Example 1, the winding loosens during winding, and its running properties are extremely poor.

Furthermore, since the magnetic recording medium according to the present invention can be produced by simply applying a quaternary ammonium salt solution on the base or magnetic layer of the magnetic recording medium, it is possible to create the magnetic recording medium by simply applying a quaternary ammonium salt solution onto the base or magnetic layer of the magnetic recording medium. Compared to conventional magnetic recording media, it is easier to make and costs less.

Furthermore, if the quaternary ammonium salt according to the present invention is interposed between the magnetic layer and the base layer, the quaternary ammonium salt of the present invention will be more effective when the quaternary ammonium salt is interposed between the magnetic layer and the base layer than when it is interposed on the surface of the magnetic recording medium. The class ammonium salt is particularly difficult to adhere to the magnetic head, etc., and the magnetic head, etc. is less likely to be damaged.

In addition, in the general formula of the quaternary ammonium salt according to the present invention, R
1 is any hydrocarbon such as an alkyl group or allyl group having one or more amide groups, R2, R3 and R4 are any hydrocarbons, X is Cl, . Br. I. Any anion such as SO4, PO4, OH, etc. may be used, and various other types are possible in addition to the quaternary ammonium salts in the above embodiments.

As mentioned above, the magnetic recording medium according to the present invention has the general formula ± \ ▲V4'
(In the formula, R1 is a hydrocarbon containing one or more amide groups, R2, R3 and R4 are hydrocarbons, and X is an anion.) A quaternary ammonium salt represented by Since it is interposed between the magnetic layer and the base layer of the recording medium, it is possible to effectively prevent static electricity on the magnetic recording medium, and in particular, it is possible to more effectively reduce the charging voltage, making it less likely that discharge noise will occur, and also reducing the charging voltage. The half-life is extremely short, and since the quaternary ammonium salt is not adsorbed to magnetic powder, there is no reduction in coercive force, etc., and it is extremely effective in preventing static electricity. For example, the running properties and winding shape of the magnetic tape are improved, and the magnetic tape is easy to manufacture and can be manufactured at low cost.

Claims (1)

[Claims] General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼(However, in the formula,
R_1 is a hydrocarbon containing one or more amide groups, R_2
, R_3 and R_4 are hydrocarbons, and X represents an anion) is interposed on the surface of a magnetic recording medium or between a magnetic layer and a base layer of a magnetic recording medium. Medium.