JPS6286532A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To upgrade corrosion resistance and to improve runnability and durability by using specific compds. on the layer surface of a magnetic recording medium. CONSTITUTION:At least the compd. expressed by the formula I among the compds. expressed by the formulas I-IV (R1, R2 are perfluoroalkyl or alkyl, both of which are not alkyl. R3 is an alkyl, alkenyl, M is H, alkali metal atom, ammonium, X is a halogen atom. n, m, l are 20 integers. p is 1-4, q is 0-3, there is no case in which all of R3 are methyl when p+q=4) is used for the surface layer of the magnetic recording medium. The other compds. are prefer ably used at a mixing ratio of 0.1-10 with 1 compd. expressed by the formula I. The magnetic film to be applied may be any of a coating type, thin film type by vapor deposition, etc. of which the effect is remarkable with the thin film type. The corrosion resistance of the magnetic tape is thereby upgraded and the excellent runnability and durability are obtd. Such magnetic recording medium is widely used in audio, video and computer fields.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to magnetic recording media, and more specifically to magnetic tapes.

(Prior Art) Magnetic recording media such as magnetic tapes, magnetic sheets, and magnetic disks are widely used in the audio field, video field, and combinator field. However, as the demand for high-density recording has increased recently, this coated type has been replaced by a coated type, which has a lower recording density due to the amount of binder, and has a higher saturation magnetization. In addition, there are many thin-film magnetic recording media in use in which a ferromagnetic metal thin film can be formed on a support by direct vapor deposition, sputtering, ion blating, etc. without the need for a binder.

However, the ferromagnetic layer of such a thin-film recording medium has a large coefficient of friction, so when it is run on a video deck, for example, it may be rubbed by a magnetic head, producing a frictional noise called tape squeal. When this friction is severe, the tape may stop. Not only do they have poor running performance, but they are also prone to scratches due to friction with magnetic heads, guide rollers, liners, etc.

For this reason, the so-called still durability, which is used when viewing still images by playing back on a video tape deck, and the so-called repeat durability, which is seen by repeatedly playing this tape and viewing its durability, are extremely inferior to those of a coating shop, and are not practical for practical use. The current situation is that it cannot withstand it. Furthermore, when a metal thin film is exposed to air, the metal is oxidized by the presence of oxygen and moisture, resulting in poor corrosion resistance. For example, the iron oxide that is produced when subjected to oxidative corrosion exhibits no magnetism, which not only reduces the recording density as a recording medium, but also causes noise due to the corroded and scratched areas. Sometimes.

In order to solve these problems, a coating film is provided on the ferromagnetic metal thin film, but in this case, it is necessary to reduce the so-called spacing p, which causes a loss of output when scanning the magnetic layer with a magnetic head. In order to do this, the film thickness must be made thinner.

In order to solve these problems, various inorganic or organic compounds have been conventionally attached to or overcoated on the surface of the magnetic layer. For example, JP-A-56-14
No. 3540 discloses a magnetic recording medium in which a metal thin film layer is provided with a layer mainly composed of polyurethane resin. Also,
JP-A-58-133631 discloses a magnetic recording medium in which a sorbitan ester is deposited on a metal thin film layer.

However, these are not yet sufficiently durable for practical use, especially when rubbed by a magnetic head. Furthermore, Japanese Patent Application Laid-Open No. 146027/1983 discloses a magnetic recording medium in which a surface treatment film made of phosphate ester or its metal salt is provided on a metal thin film. The invention also states that metal salts of phosphoric acid esters are preferred. However, even with this metal salt of phosphoric acid ester, durability such as the above-mentioned tape squeal and still durability is not sufficient. In particular, recent trends in magnetic recording technology include, for example, in audio tapes, there is a shift from compact cassettes to microphone cassettes, and in the video field, from the current VH8 and β formats to 8mm video and electronic cameras. As a result, the trend is toward further miniaturization and higher density, so for example, in the case of &F magnetic tape, the tape traveling force has become complicated and the contact with guide balls, guide rollers, etc. As the number of opportunities for friction increases and the frequency of friction increases, further improvements in mechanical properties such as runnability and durability are desired.

In addition, Japanese Patent Application Laid-Open No. 60-85427 discloses trialkyl phosphorus containing an alcohol having 10 or more carbon atoms, which is applied to the above-mentioned requirement, and greatly improves running performance and durability, but further improvements are needed in practical use. It is desirable.

For this reason, it has been desired to develop a magnetic recording medium that has corrosion resistance, runnability, and durability that meet recent demands.

(Object of the Invention) An object of the present invention is to provide a magnetic recording medium that is corrosion resistant, has good running properties, and has good durability, in accordance with the above-mentioned demands.

(Structure of the Invention) The object of the present invention is to satisfy the following general formula (1) and general formula (2).
, is achieved by a magnetic recording medium characterized by having at least a compound represented by general formula +11 out of compounds represented by general formula (3) or general formula (4) on the layer surface of the magnetic recording medium.

General formula (tla, COOR2 General formula (21 CnF2n+I COOM General formula (3
) CmF2m+4803M(R3)q In the formula, R1 and R2 are a perfluoroalkyl group or an alkyl group. However, R+ and R2 cannot both be a furkyl group. R3 is an alkyl group or an alknyl group. M is a hydrogen atom, an alkaline earth atom, or an ammonium group, and X is a hapogen atom.
, m and l are integers of 20 or less, p is 1 to 4, q is O to 3
is an integer. Note that when p+q=4, all R3s are not methyl groups.

In the above-mentioned compound giving a preferred embodiment of the present invention, in the above general formula, R1 and R2 are perfluoro I:I furkyl groups or alkyl groups having 20 or less carbon atoms, and Rs has 10 to 20 carbon atoms. fulkyl groups.

Further, M is preferably hydrogen, sodium, potassium atom or ammonium group, and X is preferably chlorine or iodine.

Furthermore, it is preferable that n, m and l are each 3 to 10, p is 1, and q is O or l.

The compound according to the present invention can be applied to a coating type in which a magnetic paint containing magnetic powder or the like is applied to a support, and a thin film type magnetic recording in which a ferromagnetic metal thin film is directly applied to a support by a method such as vapor deposition. Although it can be applied to any medium, the effect is remarkable in thin film type. Furthermore, it may be applied to the surface layer of a back coat layer containing a nonmagnetic filler.

Next, specific examples of the compounds according to the present invention will be given.

[Example of compound represented by general formula (1)]; (11C4Fr
COOCF3 (21Cs Fr3COOC2P 5 (31Ca Fr3COOCF3 (41Cl0F21COOC3F?) (5) Cl2F25COOCF3 (61Ca Fr3COOCHs [Example of compound represented by general formula (2)]; (1) 03
F7COOH (2) Cs P7 C00K 13) 08 Fr3COOC (4) C8Fr3COOC (s> CIl FI7COONH4(6) C1
oF2sCOOK (7) CtsFvCOOK [Example of compound represented by general formula (3)]; (11CaFv
SO3K (2) CgFksSO2K (31C3P17SO3 to 141 010F21SO3NH4 [Example of compound represented by general formula (4)]; fil C6
F13NH3I f2) C? FtsNH3I +31 C3F17NH3I (4) Cl0F21NH3I f5) C4F9NH3I [61(C6F+3)2NH2I (7) 06F, 3-NH4I 16H93 f8) CeFuNH3C1 (9) C6F13NH3 (C1 out 33) 2 This invention In the compound of general formula (1) The mixing ratio of the other compounds to the amount of the compound of general formula (1) is 0.1 to 10, preferably 0.5 to 5.

When the above compound is applied to the magnetic layer side and, if necessary, to the back coat layer side, it imparts remarkable lubricity to the layer surface, greatly improving runnability and durability, and significantly improving corrosion resistance. increase

The total amount applied to the layer surface is 0.5 to 3019/i, preferably 1 to 10 mfl/d. In addition, there is a lubricating layer on the surface of the layer.
When used as an overfoot layer such as a rust prevention layer, the film thickness is preferably 50 to 500X. If it is 500 Å or more, the spacing loss will be large, and if it is thinner than 50X, it will have poor lubricity.
The effect on corrosion resistance will be reduced.

The combination of these compounds with other lubricants, such as phosphoric esters, gives even better results for the lubricity.

Lubricants that can be used in combination include silicone oil, graphite, carbon black graft polymer, molybdenum disulfide, tungsten disulfide, fatty acids such as lauric acid, palmitic acid, oleic acid, stearic acid, behenic acid, myristic acid, and butyl stearate. Fatty acid esters such as octyl palmitate and octyl 4-ritate can be mentioned.

A layer surface containing a mixture of these compounds is formed by applying a paint, and this paint contains a mixture of said compounds from 0.005% by weight! It consists of an organic solvent solution containing heavy ingredients. Organic solvents for this purpose include toluene, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, xylene, benzene, cyclohexanone, methanol, ethanol, prop/(nol, impropatol,
Single or mixed solvents such as butanol, ethyl cellosolve, methyl cellosolve, etc. are used.

To apply this paint, methods such as dipping in the above paint, reverse roll method, extrusion method, doctor blade method, gravure printing method, spray method, etc. are used. The resulting coating is dried by conventional means.

The ferromagnetic metal thin film in the present invention is Fe.

Metals such as Co and Ni or re-Co%Fe -Ni
, Co-Ni.

re -Co-NisFe-Rh%Fe-Cu, C
o-Cu5Co-Au.

Co-Y, Co-La5Co-Pr, Co-G
d%Co-8m, Co-Pt%Ni-Cu, Mn
-Bi, Mn-8bMn-8b1, Fe-Cr.

Co-Cr%Ni-Cr, Fe-Co-Cr, re
A ferromagnetic alloy such as -Co-Ni-Cr formed into a thin film by vacuum deposition is used. The thickness of this metal thin film is preferably about 500X to 5000A.

Furthermore, those deposited in an oxygen atmosphere exhibit better durability.

Regarding the coated magnetic layer and back coat layer, conventional techniques can be used as they are.

The support on which the metal thin film is formed may be a plastic base such as polyester, polyethylene terephthalate, polyimide, polyamide, polyamideimide, polyvinyl chloride, cellulose triacetate, polycarbonate, polyethylene naphthalate, or AI! ,
A/Gold alloy Ti%Ti alloy, a metal plate such as stainless steel, etc. are used.

(Example) Next, the present invention will be described in detail, but the present invention is not limited thereto.

Example 1 Co-N on polyethylene terephthalate with a thickness of 7 μm
A metal thin film layer was formed by vapor depositing Ni (20% by weight) to a thickness of 1000 A.

On this metal thin film layer, a lubricant as shown below was dissolved in ethyl cellosolve and applied to a wet film thickness of 5 μm. Then, they were dried, slit, and packed into cassettes to obtain Samples 1 to 11.

[Comparative sample]; Sample 1 C7PI5COOK 5119 /ze Sample 2 C7FI5SO3K 5 recommendation 9 /ld Sample 3 Cs P13NH3I 58g /ze
Sample of the present invention]; Sample 4 06F13COOCF3 511F/r
rt sample 5 C6F1COOCF3 5 Q/m' sample 6 Cy FlsCOOK 3 shoulder 9/m”
06FtaCOOCF3 319/m” Sample 7 C7F15COOK 5111
i+/rlC6FI3COOCF3
3 wings 9/rrl sample 8 06F13NH3I 3 m9 /zeC6
F13COOCF3 3 Shoulder 9/m Sample 9 C6FtaNH3I 5 "9'/ rr
lC6F13COOCF3 3 shoulder 9/rl sample 10 07F15SO3K 3 Q/mC6
FI3COOCF3 3 y / , 1 sample 11 C7F15SO3K 5 shoulder 9/rlC6P
H3COOCF3 3119/m The coefficient of friction of the magnetic surface of the magnetic tapes of Samples 1 to 11 was measured, and the cassettes were placed on a deck to observe running performance, and still durability and repeated playback durability were measured.

As can be seen from these results, the combination of the two types of compounds of the present invention improves running properties and durability.

Moreover, perfluorofuryl ester shows good results even when used alone.

Claims (1)

[Claims] Among the compounds represented by the following general formula (1), general formula (2), general formula (3), or general formula (4), at least the compound represented by general formula (1) can be magnetically recorded. 1. A magnetic recording medium comprising a layer on the surface of the medium. General formula (1) R_1COOR_2 General formula (2) CnF_2n_+_1COOM General formula (3
) CmF_2m_+_1SO_3M General formula (4) ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼ [In the formula, R_1 and R_2 are perfluoroalkyl groups or alkyl groups. However, R_1 and R_2 are never both alkyl groups. R_3 is an alkyl group or an alkenyl group. M is a hydrogen atom, an alkali metal atom or an ammonium group, and X is a halogen atom. Further, n, m and l are integers of 20 or less, p is an integer of 1 to 4, and q is an integer of 0 to 3. Note that when p+q=4, all R_3 are not methyl groups. ]