JPS5928227A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording medium having an extremely superior antistatic effect, high magnetic flux density and high sensitivity and undergoing hardly sticking of dust by interposing a resin layer contg. a specified antistatic agent and carbon black between a magnetic layer and a support. CONSTITUTION:The desired resin of a resin layer contg. an antistatic agent and carbon black is polyurethane resin, polyester resin, acrylic resin, nitrile rubber, butyral resin or the like. The resin is dissolved in an org. solvent such as toluene, methyl ethyl ketone or cyclohexanone, and prescribed amounts of a specified antistatic agent and carbon black are added to the soln. and uniformly mixed. The resulting soln. is coated on a support by a coating means such as gravure coating so as to make the thickness about 0.1-1.0mum after drying. The soln. is dried, and a magnetic coating material contg. magnetic powder, a binder and other additives is coated by a conventional method to form a magnetic layer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording medium, and by providing a resin layer containing a specific antistatic agent and carbon black between a magnetic layer and a support, the magnetic recording medium can be improved. It has excellent antistatic properties and is difficult for dirt and dust to adhere to.
Furthermore, it is an object of the present invention to provide a magnetic recording medium that has good magnetic flux density and sensitivity, and is highly durable in that the magnetic layer is difficult to peel off.

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-Fetus in the magnetic layer has a high electrical resistance, the electrical resistance of the magnetic tape is high, and therefore the magnetic tape is extremely easily charged with static electricity due to friction with the magnetic head, guide pin, etc. Dirt, dust, etc. easily 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 carbon black between the support and the magnetic layer, the decrease in magnetic flux density and sensitivity can be prevented. They have found that the antistatic effect is almost negligible and sufficiently satisfactory, and that the magnetic layer is less likely to peel.

The resin of the resin layer containing the antistatic agent and carbon black used in the present invention includes polyurethane resin,
Polyester resins, acrylic resins, nitrile rubber, butyral resins, etc. are desirable, such as N-2304 from Nippon Polyurethane Co., Ltd. and Byron 20 from Toyobo Co., Ltd.
0.300, Japan Zeono Hiker 1432, I
, Sekisui Co., Ltd.'s Eslec B, etc.

Then, a predetermined amount of a specific antistatic agent and carbon black are added to a solution in which such a resin is dissolved in an organic solvent such as toluene, methyl ethyl ketone, or cyclohexanone, and the antistatic agent and carbon black are mixed uniformly. A solution containing a binder, carbon black, and a resin is coated onto a support using a coating method such as gravure coating so that the dry thickness is approximately 0.1 to 1.0 μm, and after drying, magnetic powder, a binder, A magnetic coating containing various other additives is applied by a conventional method to form a magnetic layer.

Similarly, 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 r Fe 20.
3, Fe 304, CO-containing 7- Fe 20
3. Metals, etc. are used, and as binders, for example, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, polyurethane resins, nitrocellulose, epoxy resins, etc. are used, and as organic solvents for magnetic paints, for example, toluene is used. , methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, tetrahydrofurano, etc. are used.

Some specific examples of the magnetic recording medium according to the present invention will be described below.

Example 1 15 parts by weight of carbon black, 4 parts by weight of amine salt (Esomin T/12 manufactured by Lion Oil Co., Ltd.), 40 parts by weight of a mixed solvent of methyl ethyl ketone, toluene and methyl isobutyl ketone.
0 parts by weight, 100 parts by weight of polyurethane elastomer,
After uniformly mixing and dispersing with a ball mill etc., this solution is applied onto a support such as a polyester film, and after drying, a magnetic paint (not containing carbon black or antistatic agent) is further applied thereon. After calendar processing,
The tape is heat-treated at about 55° C. for about 20 hours and slit into a predetermined length to obtain, for example, a magnetic tape for a video tape recorder.

Example 2 A mixed solution of 15 parts by weight of carbon black, 4 parts by weight of an alkyl ester type antistatic agent (Newcol 150 manufactured by Nippon Nyukazai Co., Ltd.), 400 parts by weight of a mixed solvent of methyl ethyl ketone, toluene and methyl isobutyl ketone, and 100 parts by weight of a polyurethane elastomer was prepared. A magnetic tape is obtained in the same manner as in Example 1.

Example 3 15 parts by weight of carbon black, 3 parts by weight of an alkyl ether type antistatic agent (IJ Mina N manufactured by Marubishi Yuka Industries, Ltd.),
A magnetic tape is obtained in the same manner as in Example 1 using a mixed solution of 400 parts by weight of a mixed solvent of methyl ethyl ketone, toluene and methyl isobutyl ketone, and 100 parts by weight of a polyurethane elastomer.

Example 4 15 parts by weight of carbon black, alkyl sulfonate (
A magnetic tape is obtained in the same manner as in Example 1 using a mixed solution of 3 parts by weight of Bayer's 5tatexan KI), 400 parts by weight of a mixed solvent of methyl ethyl ketone, toluene and methyl isobutyl ketone, and 100 parts by weight of a polyurethane elastomer.

Example 5 15 parts by weight of carbon black, alkyl phosphate (
Using a mixed solution of 4 parts by weight of Nyrenone N [119M] manufactured by Daiichi Kogyo Seiyaku Co., Ltd., 400 parts by weight of a mixed solvent of methyl ethyl ketone, toluene and methyl isobutyl ketone, and 100 parts by weight of polyurethane distomer, magnetic Get the tape.

Example 6 15 parts by weight of carbon black, quaternary ammonium salt (
A magnetic tape was obtained in the same manner as in Example 1 using a mixed solution of 4 parts by weight of OA'rANAO5N (available from American Cyanamid Co.), 400 parts by weight of a mixed solvent of methyl ethyl ketone, toluene and methyl isobutyl ketone, and 100 parts by weight of polyurethane distomer. .

Example 7 15 parts by weight of carbon black, 4 parts by weight of Nrubitan derivative (Turupon S manufactured by Toho Chemical Co., Ltd.), methyl ethyl ketone,
A magnetic tape is obtained in the same manner as in Example 1 using a mixed solution of toluene, 400 parts by weight of methyl isobutyl ketone, and 100 parts by weight of polyurethane elastomer.

Example 8 15 parts by weight of carbon black, betaine type antistatic agent (
Nippon Nyukazai Co., Ltd.'s Chixtool R2) 5 parts by weight, 400 parts by weight of a mixed solvent of methyl ethyl ketone, toluene and methyl imbutyl ketone, 100 parts by weight of polyurethane elastomer
A magnetic tape is obtained in the same manner as in Example 1 using parts by weight of the mixed solution.

Example 9 15 parts by weight of carphone black, 3 parts by weight of imidacillin type antistatic agent (Livoin LH manufactured by Lion Oil Co., Ltd.), 400 parts by weight of a mixed solvent of methyl ethyl ketone, toluene and methyl isobutyl ketone, 10 parts by weight of polyurethane elastomer
A magnetic tape is obtained in the same manner as in Example 1 using 0 parts by weight of the mixed solution.

Example 10 15 parts by weight of carbon black, 2 parts by weight of amine salt (Esomino T/12 manufactured by Lion Oil Co., Ltd.), 2 parts by weight of alkyl phosphate (Nyrenone Nα19M manufactured by Daiichi Kogyo Seiyaku Co., Ltd.),
A magnetic tape is obtained in the same manner as in Example 1 using a mixed solution of 400 parts by weight of a mixed solvent of methyl ethyl ketone, toluene and methyl isobutyl ketone, and 100 parts by weight of a polyurethane elastomer.

Example 11 15 parts by weight of carbon black, 2 parts by weight of an alkyl ether type antistatic agent (IJ Mina N manufactured by Marubishi Yuka Kogyo Co., Ltd.),
Quaternary ammonium salt (0A from American Cyanamid Co.)
A magnetic tape is obtained in the same manner as in Example 1 using a mixed solution of 3 parts by weight of TANAOSN), 400 parts by weight of a mixed solvent of methyl ethyl ketone, toluene and methyl isobutyl ketone, and 100 parts by weight of polyurethane distomer.

Example 12 15 parts by weight of carbon black, alkyl sulfonate (
Bayer's 5tatexan KI) 2 parts by weight,
Quaternary ammonium salt (0A from American Cyanamid Co.)
A magnetic solution was prepared in the same manner as in Example 1 using a mixed solution of 4 parts by weight of vinyl chloride-vinyl acetate-vinyl alcohol copolymer, and 400 parts by weight of a mixed solvent of methyl ethyl ketone, toluene, and methyl imbutyl ketone. Get the tape.

Example 13 15 parts by weight of carbon black, quaternary ammonium salt (
A carbon black with a composition of 4 parts by weight of 0ATANAO5N (produced by American Cyanamid Co., Ltd.), 400 parts by weight of a mixed solvent of methyl ethyl ketone, toluene, and methyl isobutyl ketone, and 100 parts by weight of a polyurethane elastomer was used. After adsorption, a mixed solvent and a polyurethane elastomer are added to perform mixing and dispersion, and using this solution, a magnetic tape is obtained in the same manner as in Example 1.

Comparative Example 1 A magnetic tape is obtained by applying a magnetic paint (containing carbon black) directly onto a support such as a polyester film, without providing a single layer of polyurethane elastomer containing carbon black and an amine salt in Example 1.

Comparative Example 2 A magnetic tape is obtained in the same manner as in Example 1 using a mixed solution of 15 parts by weight of carbon black, 400 parts by weight of a mixed solvent of methyl ethyl ketone, toluene and methyl isobutyl ketone, and 100 parts by weight of polyurethane elastomer.

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 (■), half-life (seconds), static friction coefficient at the initial stage and after 50 repeated runs) (μS)) and peeling resistance of the magnetic layer (durability dust when adhesive tape is attached to the surface of the magnetic layer and removed) are measured as shown in the table.

(11) 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 charging voltage is as low as 650 to 730μ, and is reduced by half. The period is short at 28 to 33 seconds, and there is not much difference between the initial μS and the μS after 50 repeated runs, and magnetic tape has almost no adverse effects even after repeated runs. On the other hand, the magnetic tape of the comparative example has a high charging voltage of 1050 to 1160 V, a long half-life of 95 to 152 seconds, and furthermore, the μS after repeated running 50 times is significantly larger than the initial μS. ,
Therefore, the magnetic tape of the comparative example easily generates static electricity due to sliding contact with the magnetic head, guide pin, etc. during tape running, easily causes charging phenomenon, and easily attracts dirt and dust. The magnetic tape of the invention does not cause any charging phenomenon due to sliding contact with magnetic heads, guide pins, etc. during tape running, does not easily attract dirt and dust, and has good running properties. It can be seen that it is.

Further, the magnetic tape of the present invention has carbon (12) in the magnetic layer.
Since it does not contain black, the magnetic paint has good dispersibility and there is no deterioration in magnetic properties such as a decrease in magnetic flux density or a decrease in sensitivity.

Furthermore, since the magnetic tape of the present invention has a binder resin layer containing carbon black, amine salt, etc. between the support and the magnetic layer, the magnetic layer has excellent durability. Even if carbon black is present, it is much better than when only carbon black is included.

Comparison with Examples 6 and 13 shows that even if a specific antistatic agent is adsorbed on the surface of carbon black, it has almost no effect on the characteristics of the magnetic recording medium, and the carbon black used in the present invention has almost no effect on the characteristics of the magnetic recording medium. Examples include graphite carbon, Keracheno Black EC (Akzo), Palkan XO (Cabot), acetylene black (Denki Kagaku Kogyo), other color carbons, filler carbons, etc. 5 to 100 parts by weight of a polyinsyanate such as Coronae) L (manufactured by Nippon Polyurethane) is added to a resin solution containing L, and this solution is heated at about 55°C for 24 to 72 hours after coating, and then magnetic paint is applied. The magnetic tape may also be obtained by coating the magnetic tape.

In addition, antistatic agents such as amine salts and carbon black,
It is interposed in the layer between the magnetic layer and the support, and the amount of antistatic agent such as amine salt is about 3 to 40 parts by weight per 100 parts by weight of magnetic powder contained in the magnetic layer. Approximately 10 to 35 parts by weight of carbon black provides a sufficient antistatic effect and also prevents the magnetic layer from peeling off.

As described above, the magnetic recording medium according to the present invention includes an amine salt, an alkyl ester type, an alkyl ether type, an argyl sulfonate, an alkyl phosphate, a quaternary ammonium salt, a sorbitan derivative, Since a resin layer containing at least one petaino-type or imidacilline-type antistatic agent and carbon black is provided, magnetic recording media such as magnetic tapes, floppy disks, and hard disks are susceptible to static electricity generation. Even when used in an environment, charging phenomenon can be effectively prevented, the coefficient of friction is small, the wear of the magnetic layer is correspondingly small, and the running properties are also good.Furthermore, the magnetic layer does not easily peel off, making it durable. It also has the advantage of not causing any deterioration in magnetic properties such as a decrease in magnetic flux density or sensitivity.

(15) 149-

Claims (1)

[Claims] At least one type of antistatic agent of amine salt, alkyl ester type, alkyl ether type, alkyl sulfonate, alkyl phosphate, quaternary ammonium salt, nrubitan derivative, betaine type, or imidacilline type is provided between the magnetic layer and the support. A magnetic recording medium comprising a resin layer containing carbon black and carbon black.