KR910000211B1 - Magnetic recording carrier - Google Patents

Abstract

A magnetic recording media comprises a metallic thin film layer formed by coating one surface of a non-magnetic substrate with a ferromagnetic metal or its alloy, and a back coat layer formed by coating the other surface of the film with a coating liquor. The coating liquor is prepd. by mixing at least one of organic polysiloxane cpd. of formula (I) with a resin, and dissolving the mixt. in an organic solvent. In (I), Z is 1-50 wt.% R1CO or 50-99 wt.% R2(O-CHH-CHR3)n; R1 is C7-17 hydrocarbon; R2 is C6-18 hydrocarbon; R3 is H or methyl; l is 1-100; m is 1-50; n is 1-20; Rf is C1-18 perfluoro alkyl. The media has a good travel- stability in the magnetic tape.

Description

Magnetic recording media

1 is a experimental diagram of the kinetic friction coefficient.

* Explanation of symbols for main parts of the drawings

A: Drum B: Sample Tape

C: Tension detection part D: Load weight

T ₁ : Gravity by Load Weight D ₂ : Tension of Tape

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium. In particular, a thin film layer of a ferromagnetic metal or alloy is formed on a nonmagnetic support by vacuum deposition, sputtering, ion plating, or the like to form a recording layer, and a back coat on the opposite side of the recording layer. A magnetic recording medium having a back coat layer formed thereon.

Recently, with the increase in the popularity of video tape recorders (V.T.R), studies are being actively conducted to provide magnetic recording media having excellent driving characteristics, and high density of magnetic recording media is required in accordance with the trend of light and short reduction of electronic products.

In order to increase the density of the magnetic recording medium, a magnetic layer using a thin film layer formed by forming a ferromagnetic metal such as Ni, Co, Fe, etc. to a thickness of several hundreds of micrometers-1 mu m on a nonmagnetic support by vacuum deposition, ion framing, and sputtering As the recording medium has been proposed, a review thereof is actively discussed.

The magnetic recording medium thus produced is capable of high-density recording, has an extremely smooth surface, and has excellent characteristics without a signal noise ratio due to transfer.

However, the tape manufactured as described above has a disadvantage in that curling occurs at both ends of the film because the thermal expansion coefficient and the elastic modulus of the support layer of the magnetic recording medium and the metal thin film layer are different.

In addition, when the tape is mounted in the deck, the magnetic surface of the magnetic tape causes adhesion with the guide roll. The smoother the metal thin film layer, the higher the coefficient of friction between the magnetic layer and the guide roll. There are disadvantages such as deformation, screen shaking, and output fluctuation.

In addition, the blocking phenomenon with the tape in contact when the tape is wound on the reel is more severely generated so that the surface is smooth.

Therefore, the magnetic recording medium in which the metal thin film layer is formed by vacuum deposition, ion framing, and sputtering as described above is used to secure driving stability while maintaining the advantages of high density and high sensitivity of electronic recording due to smoothness of the metal thin film layer. The problem is that the friction coefficient must be lowered.

Accordingly, it is an object of the present invention to provide a magnetic recording medium having excellent running stability to a magnetic recording medium having the above smooth metal thin film layer.

In order to solve the above problems, the present inventors have a good curling effect of the organic polysiloxane compound and the curl phenomenon is well fixed by the back coat layer containing at least one organic polysiloxane compound on the back surface of the support on which the ferromagnetic metal thin film layer is formed. The blocking phenomenon can be prevented, and output fluctuation due to adhesion with the guide roll is lowered, so that the running stability is good.

The organic polysiloxane compound used in the present invention is represented by the following general formula.

으로 표시되는 기이고, R¹은 탄소수 7-17인 포화 또는 불포화의 1가 탄화수소기이고, R²은 탄소수 6-18인 포화 또는 불포화의 1가 탄화수소기이고, R³은 수소 또는 메틸기이고, 1은 1-100의 정수이고, m은 1-50의 정수이고, n은 1-20의 정수이며, R^f는 탄소수 1-8의 퍼플루오로 알킬기임)(Wherein one of Z is a group represented by 1-50% by weight of R ¹ Co and the other is 50-99% by weight of

R ¹ is a saturated or unsaturated monovalent hydrocarbon group having 7 to 17 carbon atoms, R ² is a saturated or unsaturated monovalent hydrocarbon group having ⁶ to 18 carbon atoms, R ³ is hydrogen or a methyl group, 1 is an integer of 1-100, m is an integer of 1-50, n is an integer of 1-20, R ^f is a perfluoro alkyl group having 1-8 carbon atoms)

Examples of R ¹ mentioned above include C ₇ H _15- , C ₉ H _19- , C ₁₁ H _23- , C ₁₃ H _27- , C ₁₅ H _31- , C ₁₇ H _31- , C ₁₇ H _33- , C ₁₇ H _35- , and the like, and as R ² , C ₆ H _13- , C ₈ H _17- , C ₁₀ H _19- , C ₁₀ H _21- , C ₁₂ H _25- , C ₁₄ H _29- , C ₁₆ H _33- , C ₁₈ H _35- , C ₁₈ H ₃₇ -and the like.

In addition, R ^f represents a perfluoro alkyl group having 1 to 8 carbon atoms, which includes -CF ₃ , -C ₂ F ₅ , -C ₃ F ₇ , -C ₄ F ₉ , -C ₅ F ₁₁ , -C ₆ F ₁₃ , -C ₇ F ₁₅ , -C ₈ F ₁₇ .

It is preferable that the usage-amount of the said organic polysiloxane compound exists in the range of 0.01-10 weight% with respect to resin used together.

If it is less than 0.01% by weight, the desired lubricating effect cannot be obtained. If it is higher than 10% by weight, the organic polysiloxane compound leaks to the surface of the resin coating layer and is transferred to the adjacent ferromagnetic metal thin film layer at the time of winding, thereby adversely affecting the magnetic properties.

A better range is 0.01-5% by weight.

Examples of the resin used in the present invention include cellulose derivatives, vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinyl acetate-vinyl alcohol copolymers, vinyl chloride-vinylidene chloride copolymers, polyurethane resins, phenoxy resins, and phenolic resins. Or an amino resin, melamine resin, epoxy resin, urea resin, alkyd resin, trifunctional isocyanate, or the like, alone or in combination of two or more thereof.

In addition, it is preferable that the thickness of the back coat layer containing an organic polysiloxane compound and resin exists in the range of 0.1 micrometer-3 micrometers in this way.

If the coating thickness is less than 0.1㎛, the blocking effect is reduced, the friction coefficient is reduced, and if it is thicker than 3㎛, curling occurs toward the back coat.

As a material for forming the ferromagnetic metal thin film layer on the surface of the support, a metal such as Co, Ni, Fe, or an alloy thereof is used, and these are supported by a polyester film or the like by plating, vacuum deposition, sputtering, ion plating, or the like. A metal thin film layer is formed on the surface.

As a method of forming the back coat layer of the present invention on the opposite side of the support, after forming a ferromagnetic metal thin film on the surface of the support as described above, the single or mixed resin selected from the above-mentioned resins together with at least one organic polysiloxane compound The solution is dissolved in a suitable organic solvent to form a solution, which is then formed on the back side of the support and dried.

As the organic solvent to be used, solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, toluene, xylene, tetrahydrofuran, methanol and ethanol may be used alone or in combination of two or more thereof.

Hereinafter, the present invention will be described in more detail with reference to Examples.

First, the synthesis examples of the organic polysiloxane compound to be used in the examples are shown in Table 1 below.

TABLE 1

Example 1

The surface of the film was cleaned by bom bard treatment of a polyester base film having a thickness of 10 μm with Ar gas particles, and then the surface ratio of cobalt: nickel was reduced to 80 at a residual gas pressure of 5 × 10 ⁻⁵ torr. An alloy of 20 was vacuum deposited to a thickness of 0.15 占 퐉 to form a ferromagnetic metal thin film layer, and then 0.5 parts by weight of the organic polysiloxane compound of Example 1 and nitrocellulose (H-1 / 2 manufactured by Nippon Oksei Co., Ltd.) were formed on the back surface of the base film. ) 25 parts by weight and a polyurethane resin (N-2304, manufactured by Nippon Polyurethane Co., Ltd.) were applied to the back side of the film by applying a solution for applying a back coat layer obtained by dissolving 650 parts by weight of methyl ether ketone and 300 parts by weight of toluene in a mixed solvent. After drying to form a 0.5 micrometer-thick back coat layer, it cut into the predetermined width and set it as Example 1.

Example 2

A magnetic tape prepared in the same manner as in Example 1 except that the organic polysiloxane compound was used in Synthesis Example 2.

Example 3

A magnetic tape prepared in the same manner as in Example 1 except that the organic polysiloxane compound was used in Synthesis Example 3.

Example 4

A magnetic tape prepared in the same manner as in Example 1 except that the organic polysiloxane compound was used in Synthesis Example 4.

Example 5

A magnetic tape prepared in the same manner as in Example 1 except that the organic polysiloxane compound was used in Synthesis Example 5.

Example 6

A magnetic tape prepared in the same manner as in Example 1 except that the organic polysiloxane compound was used in Synthesis Example 6.

Example 7

A magnetic tape prepared in the same manner as in Example 1 except that VAGH (vinyl chloride-vinyl acetate-vinyl alcohol copolymer made by V.C.C) was used instead of nitrocellulose.

Comparative Example 1

A magnetic tape was prepared in the same manner as in Example 1 except that no organic polysiloxane compound was used.

Comparative Example 2

A magnetic tape prepared in the same manner as in Example 1 except that no back coat layer was formed.

The characteristics of the above Examples and Comparative Examples were tested and the results are shown in Table 2.

TABLE 2

The above characteristic experiment is based on the method described below.

(1) curling phenomenon

When the magnetic tape is left unattended, the phenomenon of tape sticking toward the deposition surface is visually observed.

(2) dynamic friction coefficient (μd)

The dynamic friction coefficient was measured by a conventional method as shown in the accompanying drawings.

In the drawing, A denotes a drum, B denotes a sample tape, C denotes a tension detector, and D denotes a load weight, and T ₁ denotes a load T ₂ by a weight D.

When the tape wound angle (the center angle of the fan-shape connecting the tape wound end at the center of the drum as radian value) is θ, the dynamic friction coefficient μd is calculated by the following equation.

(3) output fluctuation

The sample tape is inserted into a VHS video tape recorder and the output fluctuation is measured when 7KHz is applied to the audio track.

(4) screen shaking

Visually observe the shaking phenomenon caused by the vibration of the tape when the tape is running.

As shown in Table 2, the present invention could provide a magnetic recording medium having no curling phenomenon and high running stability.

Claims (1)

In a magnetic recording medium having a ferromagnetic metal thin film layer formed of a metal or an alloy thereof on one side of a nonmagnetic support, at least one organic polysiloxane compound represented by the following general formula is mixed with a resin and then dissolved in an organic solvent to apply a coating solution. And a coating layer formed on the surface of the film opposite the metal thin film layer to form a back coat layer.

(Wherein one of Z is a group represented by 1-50% by weight of R ¹ Co, the other is 50-99% by weight of

R ¹ is a saturated or unsaturated monovalent hydrocarbon group having 7 to 17 carbon atoms, R ² is a saturated or unsaturated monovalent hydrocarbon group having ⁶ to 18 carbon atoms, R ³ is hydrogen or a methyl group, and 1 is An integer of 1-100, m is an integer of 1-50, n is an integer of 1-20, and R ^f is a perfluoro alkyl group having 1-8 carbon atoms.

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