JPS6222169B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a magnetic recording medium, and by providing a resin layer containing at least a specific antistatic agent and titanium monoxide between a magnetic layer and a support,
The magnetic layer has extremely excellent peeling resistance, the magnetic recording medium has little chargeability, dirt and dust do not easily adhere to it, it has excellent running properties, and it has a high packing density of magnetic powder. It is an object of the present invention to provide a magnetic recording medium which has excellent electromagnetic conversion characteristics and light shielding properties. A magnetic recording medium such as a magnetic tape has a magnetic layer made of a mixture of magnetic powder, a binder, and various other additives formed on a support such as a polyester film, and is mainly insulating. It is structured as follows. In particular, since the magnetic powder such as γ-Fe ₂ O ₃ in the magnetic layer has high electrical resistance, the electrical resistance of the magnetic tape is high, and therefore the magnetic head
The magnetic tape is extremely easily charged with static electricity due to friction with guide pins, etc., and dirt and dust are likely to adhere to it. Therefore, anionic, cationic, nonionic, amphoteric surfactants or carbon are added to the magnetic layer, but magnetic tapes containing surfactants, etc. in the magnetic layer are fully satisfactory. At present, it is not very desirable because it does not provide an antistatic effect, and the magnetic flux density and sensitivity decrease. The present invention eliminates the above-mentioned drawbacks, namely, by providing a resin layer containing a specific antistatic agent and titanium monoxide between the support and the magnetic layer, the magnetic flux density and sensitivity are reduced. There are almost no
They have also found that it has a sufficiently satisfactory antistatic effect, that the magnetic layer is less likely to peel off, and that it also has excellent light-shielding properties. As the resin for the resin layer containing the antistatic agent and titanium monoxide used in the present invention, polyurethane resin, polyester resin, acrylic resin, nitrile rubber, butyral resin, etc. are desirable, and for example, N- 2304,
These include Toyobo's Byron 200 and 300, Nippon Zeon's Hiker 1432J, and Sekisui's Esletsuk B. Then, such a resin is used, for example, toluene,
A predetermined amount of a specific antistatic agent and titanium monoxide are added to a solution dissolved in an organic solvent such as methyl ethyl ketone or cyclohexanone, and after uniformly mixing, a solution containing the antistatic agent, titanium monoxide, and resin is prepared. is coated on the support using a coating method after gravure coating so that the dry thickness is approximately 0.1 to 1.0 μm, and after drying, a magnetic paint containing magnetic powder, binder, and various other additives is applied using a conventional method. Then, a magnetic layer is provided. Note that there are no particular restrictions on the components of the magnetic layer provided on the resin layer containing a specific antistatic agent provided on the support, and examples of the magnetic powder include γ-Fe ₂ O ₃ and Fe ₃ O _{4 .} , Co-containing γ-Fe ₂ O ₃ , metal, etc. are used as binders, for example, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, polyurethane resin, nitrocellulose, epoxy resin, etc., and magnetic paint Examples of the organic solvent used include toluene, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and tetrahydrofuran. Some specific examples of the magnetic recording medium according to the present invention will be described below. Example 1 After uniformly mixing and dissolving 100 parts by weight of TiO, 4 parts by weight of amine salt (Esomin T/12 from Lion Oil Co., Ltd.), 300 parts by weight of a mixed solvent of methyl ethyl ketone, toluene and methyl isobutyl ketone, and 15 parts by weight of polyurethane elastomer. This solution is applied onto a support such as a polyester film, and after drying, a magnetic paint (not containing carbon black) is applied thereon, calendered, and then heated at approximately 55°C for approximately 20 hours. The tape is processed and slit into a predetermined width to obtain, for example, a magnetic tape for a video tape recorder. Example 2 Using a mixed solution of 100 parts by weight of TiO, 6 parts by weight of an alkyl ester type antistatic agent (Newcol 150 from Nippon Nyukazai Co., Ltd.), 300 parts by weight of a mixed solvent of methyl ethyl ketone, toluene and methyl isobutyl ketone, and 15 parts by weight of polyurethane elastomer. A magnetic tape is obtained in the same manner as in Example 1. Example 3 A mixed solution of 100 parts by weight of TiO, 4 parts by weight of an alkyl ether type antistatic agent (Elimina N from Marubishi Yuka Kogyo Co., Ltd.), 300 parts by weight of a mixed solvent of methyl ethyl ketone, toluene and methyl isobutyl ketone, and 15 parts by weight of polyurethane elastomer. A magnetic tape is obtained in the same manner as in Example 1. Example 4 100 parts by weight of TiO, 2 parts by weight of alkyl sulfonate (Statexan KI from Bayer AG), 300 parts by weight of a mixed solvent of methyl ethyl ketone, toluene and methyl isobutyl ketone, polyurethane elastomer
A magnetic tape is obtained in the same manner as in Example 1 using 15 parts by weight of the mixed solution. Example 5 100 parts by weight of TiO, alkyl phosphate (first
Example 1 was prepared using a mixed solution of 5 parts by weight of Elenon No. 19M (manufactured by Kogyo Seiyaku Co., Ltd.), 300 parts by weight of a mixed solvent of methyl ethyl ketone, toluene and methyl isobutyl ketone, and 15 parts by weight of polyurethane elastomer.
Obtain a magnetic tape in the same manner as above. Example 6 Using a mixed solution of 100 parts by weight of TiO, 6 parts by weight of a quaternary ammonium salt (CATANAC SN from American Cyanamid Company), 300 parts by weight of a mixed solvent of methyl ethyl ketone, toluene and methyl isobutyl ketone, and 15 parts by weight of a polyurethane elastomer,
A magnetic tape is obtained in the same manner as in Example 1. Example 7 The same procedure as in Example 1 was carried out using a mixed solution of 100 parts by weight of TiO, 10 parts by weight of a sorbitan derivative (Sorbon S from Toho Chemical Co., Ltd.), 300 parts by weight of methyl ethyl ketone, toluene and methyl isobutyl ketone, and 20 parts by weight of polyurethane elastomer. to obtain magnetic tape. Example 8 Using a mixed solution of 100 parts by weight of TiO, 18 parts by weight of a betaine type antistatic agent (Texnol R2 from Nippon Nyukazai Co., Ltd.), 400 parts by weight of a mixed solvent of methyl ethyl ketone, toluene and methyl isobutyl ketone, and 30 parts by weight of a polyurethane elastomer, A magnetic tape is obtained in the same manner as in Example 1. Example 9 Conducted using a mixed solution of 100 parts by weight of TiO, 15 parts by weight of an imidazoline type antistatic agent (Libomin LH from Lion Oil Co., Ltd.), 400 parts by weight of a mixed solvent of methyl ethyl ketone, toluene and methyl isobutyl ketone, and 30 parts by weight of polyurethane elastomer. A magnetic tape is obtained in the same manner as in Example 1. Example 10 100 parts by weight of TiO, 2 parts by weight of amine salt (Esomin T/12 manufactured by Lion Oil Co., Ltd.), 2 parts by weight of alkyl phosphate (Elenon No. 19M manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), methyl ethyl ketone, toluene and methyl isobutyl ketone. Using a mixed solution of 300 parts by weight of mixed solvent and 15 parts by weight of polyurethane elastomer,
A magnetic tape is obtained in the same manner as in Example 1. Example 11 100 parts by weight of TiO, 2 parts by weight of an alkyl ether type antistatic agent (Elimina N from Marubishi Yuka Kogyo Co., Ltd.), quaternary ammonium salt (from American Cyanamid Co., Ltd.)
A magnetic tape was obtained in the same manner as in Example 1 using a mixed solution of 3 parts by weight of CATANAC SN), 300 parts by weight of a mixed solvent of methyl ethyl ketone, toluene and methyl isobutyl ketone, and 15 parts by weight of polyurethane elastomer. Example 12 100 parts by weight of TiO, 2 parts by weight of alkyl sulfonate (Statexan KI from Bayer), quaternary ammonium salt (from American Cyanamid)
CATANAC SN) 6 parts by weight, 18 parts by weight of vinyl chloride-vinyl acetate-vinyl alcohol copolymer, and 300 parts by weight of a mixed solvent of methyl ethyl ketone, toluene, and methyl isobutyl ketone. Get the tape. Example 13 Using a composition of 100 parts by weight of TiO, 6 parts by weight of a quaternary ammonium salt (CATANAC SN from American Cyanamid Company), 300 parts by weight of a mixed solvent of methyl ethyl ketone, toluene and methyl isobutyl ketone, and 20 parts by weight of a polyurethane elastomer,
After adding a quaternary ammonium salt to TiO and adsorbing it on the surface, a mixed solvent and a polyurethane elastomer are added and mixed and dispersed. This is applied onto a support such as a polyester film, and after drying, a magnetic paint (carbon After applying a film (not including black), calendering it, heating it at about 55°C for about 20 hours, and slitting it into a predetermined width to obtain, for example, a magnetic tape for a video tape recorder. Comparative Example 1 A magnetic tape is obtained by applying a magnetic paint (including carbon black) directly onto a support such as a polyester film, without providing the polyurethane elastomer layer containing the amine salt and TiO in Example 1. Comparative Example 2 A magnetic tape is obtained in the same manner as in Example 1 using a mixed solution of 100 parts by weight of TiO, 300 parts by weight of a mixed solvent of methyl ethyl ketone, toluene and methyl isobutyl ketone, and 15 parts by weight of polyurethane elastomer. Comparative Example 3 6 parts by weight of quaternary ammonium salt (CATANC SN from American Cyanamid), 300 parts by weight of a mixed solvent of methyl ethyl ketone, toluene and methyl isobutyl ketone, polyurethane elastomer 20
A magnetic tape is obtained in the same manner as in Example 1 using parts by weight of the mixed solution. Regarding the magnetic tape obtained as described above, its antistatic effect (measured at a temperature of 40°C and a humidity of 25%, charging voltage (V), half-life (seconds), coefficient of kinetic friction at the initial stage and after 50 repeated runs) (μs)) and the peeling resistance of the magnetic layer (durability when an adhesive tape is attached to the surface of the magnetic layer and then peeled off) are as shown in the table.

【table】

[Table] As can be seen from the above results, even when the magnetic tape according to the present invention is used in an environment where static electricity is likely to be generated, such as a humidity of 25%, the charged voltage remains low.
It has a low voltage of 610 to 690V, and a short half-life of 18 to 26 seconds.Furthermore, there is not much difference between the initial μs and the μs after 50 repeated runs. In contrast, the magnetic tape of the comparative example had a charging voltage of 1080
The magnetic tape of the present invention has a high voltage of ~1160V, a long half-life of 89 to 152 seconds, and the μs after 50 repeated runs is significantly larger than the initial μs. It can be seen that even when it comes into sliding contact with the head, guide pin, etc., charging phenomenon does not easily occur, dirt and dust do not easily adhere to it, and furthermore, it has good running properties. Furthermore, since the magnetic tape of the present invention does not contain carbon black in the magnetic layer, the dispersibility of the magnetic paint is good, and since the packing density of the magnetic powder can be increased, the electromagnetic conversion characteristics are also good. . In addition, the magnetic tape of the present invention has a binder resin layer containing not only TiO but also amine salt, etc. between the support and the magnetic layer, so the magnetic layer has excellent durability. Even if a binder resin layer is provided, it is much better than the case where only TiO is included. A comparison between Examples 6 and 13 shows that even if a specific antistatic agent is adsorbed on the surface of TiO, it has almost no effect on the characteristics of the magnetic recording medium. Furthermore, antistatic agents such as amine salts and TiO are interposed in the layer between the magnetic layer and the support. About 3 to 40 parts by weight of the agent, 20 to 120 parts by weight of TiO having an average particle size of about 0.01 to 5 μm, preferably about 40 to 120 parts by weight of TiO having an average particle size of about 0.01 to 1 μm.
100 parts by weight is sufficient for antistatic effect.
Furthermore, peeling of the magnetic layer is less likely to occur. In addition, 5 to 100 parts by weight of polyisocyanate such as Coronate L (manufactured by Nippon Polyurethane) is added to the intermediate layer, which is a binder resin layer containing an antistatic agent and TiO powder, in the same way as the magnetic layer. After applying the solution that will become the intermediate layer, the temperature is 24 to 72 at about 55℃.
A magnetic tape or the like may be obtained by heating for a period of time and then applying a magnetic paint. As described above, the magnetic recording medium according to the present invention has an amine salt, an alkyl ester type, an alkyl ether type, an alkyl sulfonate, an alkyl phosphate, a quaternary ammonium salt, a sorbitan derivative, At least one type of betaine type or imidazoline type antistatic agent,
Since a resin layer containing titanium monoxide is provided, it can be used for magnetic tapes, floppy disks, etc.
Even when magnetic recording media such as hard disks are used in environments where static electricity is likely to be generated, charging phenomena can be effectively prevented, and the coefficient of friction is small, the wear of the magnetic layer is correspondingly small, and the running properties are good. In addition, the magnetic layer does not easily peel off, is highly durable, does not cause deterioration of magnetic properties such as decrease in magnetic flux density or sensitivity, and has excellent light shielding properties. It has certain features such as:

Claims (1)

[Claims] 1 At least an amine salt, alkyl ester type, alkyl ether type, alkyl sulfonate, alkyl phosphate, quaternary ammonium salt, sorbitan derivative, betaine type, or imidazoline type antistatic agent is present between the magnetic layer and the support. 1. A magnetic recording medium comprising a resin layer containing one type of titanium monoxide and titanium monoxide.