JPH0495216A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain the magnetic recording medium having an excellent traveling characteristic and corrosion resistance by providing a lubricating layer contg. specific org. compds. on a magnetic recording layer. CONSTITUTION:The lubricating layer contg. at least one kind of the compds. selected from the org. compds. expressed by formula I and formula II is provided on the magnetic recording layer. In the formulas, R denotes >=8C alkyl group; RF denotes >=4C perfluoroalkyl group; n denotes 0 to 3 integer. Namely, the org. compds. to be used as a lubricant have a perfluoroalkyl group, alkyl group and polar section in one molecule and, therefore, the compds. have good compatibility (wettability, etc.) with materials, such as metals, metal oxides and binders, on the surface of the magnetic recording layer and can uniformly form a lubricant film on the magnetic recording layer. The magnetic recording medium having the high lubricity and durability is obtd. in this way.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a magnetic recording medium, and more specifically, the present invention relates to a magnetic recording medium, and more specifically, a top coat layer that is a lubricating layer of a magnetic recording layer has improved running characteristics, corrosion resistance, and durability. Concerning excellent magnetic recording media.

[Conventional technology]

Magnetic recording media require a high degree of running stability because they come into sliding contact with magnetic heads and the like. In particular, a magnetic recording medium having a magnetic recording layer made of a ferromagnetic metal thin film is easily scraped because the metal is exposed on the two surfaces, so higher lubricity is required.

In order to improve this lubricity, it has been proposed to apply various lubricants; Due to the large coefficient of friction against parts, adsorption phenomenon, so-called sticking, is likely to occur, and fatty acid-based lubricants (Japanese Patent Application Laid-Open No. 61-24017)
Lubricants have advantages and disadvantages, such as accelerating corrosion of the magnetic recording layer, and the current situation is that no lubricant with satisfactory properties as a lubricant layer of a magnetic recording medium has been obtained.

On the other hand, a magnetic recording medium using perfluoroalkylcarboxylic acid amine salt as a lubricant has recently been proposed (Japanese Patent Application Laid-Open No. 1983-1989-1).
However, in general, fluorocarboxylic acids have high acidity because they contain a large amount of electron-withdrawing F atoms, and when this type of compound is used as a lubricant,
There was a problem in that the magnetic metal in the magnetic recording layer was easily eroded and the magnetic properties were deteriorated.

[Problem to be solved by the invention]

As mentioned above, conventional perfluoroalkyl polyether-based lubricants have a large coefficient of friction against sliding members such as magnetic heads, which tends to cause adsorption phenomenon, or so-called sticking. However, when using a perfluoroalkylcarboxylic acid amine salt as a lubricant, the magnetic recording layer is corroded and corrosion resistance deteriorates. Therefore, it has a high acidity,
There is a problem in that the magnetic metal in the magnetic recording layer is eroded and the magnetic properties are deteriorated.

An object of the present invention is to solve the above-mentioned problems in the conventional technology, and to do so without corroding the magnetic recording layer and preventing deterioration of the lubricating properties even when stored for a long time or left in a corrosive environment for a long time. A magnetic recording medium having a lubricating layer is provided.

By providing a lubricating layer containing a fluoroethyleneimine-based or fluoroepoxide-based organic compound that has a specific molecular structure that is chemically stable and resistant to deterioration, it has good running characteristics and corrosion resistance. The objective is to realize a highly reliable magnetic recording medium with excellent durability.

[ll! Means to solve the problem]

In order to achieve the above object of the present invention, on a non-magnetic substrate,
In a magnetic recording medium having a magnetic recording layer formed directly or via an underlayer, the following structural formulas (1), (2), (3) or (4), (5), (
A lubricating layer containing at least one organic compound selected from 6) is provided, which further improves the running characteristics and corrosion resistance of the magnetic recording medium, resulting in a highly durable magnetic recording medium. It becomes possible to realize the medium.

RN CHz CH25(CH-)n RF
・・・＝・＝・・・(3) Or.

RCHCH2NH(CHJn Rp ・------・
(4) H RCHCH, O(CH2)n RF ・・・・・・・・・
・・・・・・・・・・・・(5)H In the above structural formulas (1) to (3,) or (4) to (6), R is an alkyl group having 8 or more carbon atoms, and RF is a perfluoroalkyl group having 4 or more carbon atoms; n represents an integer of 0 to 3;

In the magnetic recording medium of the present invention, the organic compound represented by the above structural formulas (1) to (3) or (4) to (6) used as a lubricant has a perfluoroalkyl group, an alkyl group, Because it has a polar region and a magnetic recording layer, it has good compatibility (wettability, etc.) with all substances on the surface of the magnetic recording layer, such as metals, metal oxides, binders, rust preventives, and other lubricants. Since a lubricant film can be uniformly formed and a lubricant layer with strong bonding force with the magnetic recording layer can be formed, a magnetic recording medium with high lubricity and durability can be obtained. moreover.

It can also be used in combination with magnetic paints, back coat paints, anti-rust paints, and other lubricant paints.

In addition, the organic compounds represented by the above structural formulas (1) to (3) can be obtained by polyaddition reaction of alkylethyleneimine and fluoroalkylamine, or alkylethyleneimine and fluoroalkyl alcohol, or alkylethyleneimine and fluoroalkylthioalcohol. The obtained substances are organic compounds represented by the above structural formulas (4) to (6).

Alkyl epoxides and fluoroalkyl amines.

Alternatively, it is a substance obtained by polyaddition reaction of alkyl epoxide and fluoroalkyl alcohol, or alkyl epoxide and fluoroalkylthio alcohol, both of which are highly chemically stable and difficult to deteriorate.
It does not attack the magnetic recording layer, and there is little change in the lubricating properties even after long-term storage of magnetic recording media or long-term exposure to corrosive environments.

Moreover, no deterioration of magnetic properties occurs.

In order to exhibit sufficient lubricity in the organic compound represented by the above structural formulas (1) to (3) or (4) to (6) used as a lubricant in the magnetic recording medium of the present invention,
The number of carbon atoms in R, which is an alkyl group, must be 8 or more, and the number of carbon atoms in RF, which is a perfluoroalkyl group, must be 4 or more, and in order to further improve the lubrication performance, R must be linear. In addition, when this organic compound is a liquid, it is preferable to have a double bond in R in order to reduce the viscosity and prevent sticking due to stick-slip or adsorption with the magnetic head. If the number is too large, the degree of freedom of the alkyl chain decreases and the lubricity deteriorates, so it is appropriate that the number is 4 or less.

In the magnetic recording medium of the present invention, methods for forming a lubricating layer containing an organic compound represented by structural formulas (1) to (3) or (4) to (6) on the magnetic recording layer include gravure coating, All conventional organic layer formation methods such as spin coating, vacuum evaporation, etc. are suitably used. In addition to the method of directly forming the lubricant on the magnetic recording layer, various methods can be applied, such as forming a lubricant layer on the back surface and transferring it to the magnetic recording layer, or incorporating it into a magnetic paint or back coat paint.

Further, in the magnetic recording medium of the present invention, the magnetic recording layer formed on the substrate is made of γ-Fe, O, powder.

Fe50. Powder, Co-containing-Fe, ○, Powder, Co-containing Fe50. Magnetic powder such as powder, Fe powder, Co powder, Fe-Ni powder, etc. is coated on a substrate together with a binder component and an organic solvent, and then dried.
Single metals such as O, Fe, and Ni or alloys containing these metals as main components 2 For example, Co-Ni alloy, Co-Cr
It is formed by depositing a ferromagnetic metal or alloy such as alloy, Co-P alloy, or Co-Ni-P alloy onto a substrate by various means such as vacuum evaporation, ion blasting, sputtering, plating, etc. Ru.

Further, in the magnetic recording medium of the present invention, the ferromagnetic metal thin film forming the magnetic recording layer is made of a simple metal of Co or an alloy containing Co as a main component.

A passive layer such as Co may be formed on the surface of the magnetic recording layer, that is, between the magnetic recording layer and the lubricating layer.6 The magnetic recording medium of the present invention may be made of synthetic resin such as polyester film or polyimide film. Magnetic tape based on film, glass plate, aluminum plate 1
It includes various forms of structures that come into sliding contact with a magnetic head, such as magnetic disks and magnetic drums that have a synthetic resin plate or the like as a base.

〔Example〕

Examples of the present invention will be given below and will be explained in more detail.

(Example 1) A polyester film substrate with a thickness of 10 mm was set in a vacuum evaporation apparatus, and heated under a vacuum of 10 mm Torr.

Co-Ni 80wt%-Ni20vt% alloy was heated and evaporated to a thickness of 2000 on a polyester film substrate.
A ferromagnetic metal thin film layer made of an alloy was formed. Thereafter, it was left in an oxygen atmosphere of 3 atm for 50 hours, and then placed on a magnetic recording layer consisting of 9 ferromagnetic metal thin films.

A Co passivation layer with a thickness of 50 μm was formed. Next.

The polyester film substrate on which the above ferromagnetic metal thin film layer was formed was set in a gravure coating device, and a lubricant paint with the following structural formula (1
)-1 0.1wt% IPA (isopropyl alcohol) solution was applied and dried to form a lubricating layer with a thickness of 150 mm on the 2 ferromagnetic metal thin film layer,
A magnetic tape was produced by cutting it to a predetermined width.

C, H, CH=CHC1, H, o-N-CH, -CH2
-NHCH,C,F,.

...(1)-1 (Example 2) Same as Example 1 except that a 0,1 wt% IPA solution of an organic compound represented by the following structural formula (1) = 2 was used as the lubricant paint. A magnetic tape was produced using the following method.

C,, H3□-N-CH, -CH2-NHC2H4C,
F... (1)-2 (Example 3) Example 1 except that a 0.1vt% IPA solution of an organic compound represented by the following structural formula (2>-1) was used as a lubricant paint. A magnetic tape was produced in the same manner.

(Example 4) A magnetic tape was produced in the same manner as in Example 1, except that a 0.1 wt% IPA solution of an organic compound represented by the following structural formula (2)-2 was used as a lubricant coating.

C1,H37-N-CH,-CH2-0C2H,C,F
, □ ...(2)-2 (Example 5) The same procedure as Example 1 was used, except that a 0.1 wt% IPA solution of an organic compound represented by the following structural formula (3)-1 was used as the lubricant paint. A magnetic tape was produced in the same manner.

(Example 6) A magnetic tape was produced in the same manner as in Example 1, except that a 0.1 wt% IPA solution of an organic compound represented by the following structural formula (3)-2 was used as a lubricant coating.

C1-H37N CH2CH25CxH4CsFtz
...(3)-2■ (Example 7) The above structural formula (1) used in the lubricant paint in Example 1
)-1 and perfluoropolyether [Fom+bli manufactured by Montegisson
A magnetic tape was prepared in the same manner as in Example 1, except that a solution of Q, let% ZS90 [fluorine-based solvent (manufactured by Montegisson)] mixed with Z-AM 2001) at a weight ratio of 1:1 was used. Created.

(Example 8) A magnetic tape was produced in the same manner as in Example 1, except that a 0.1 wt % EPA solution of an organic compound represented by the following structural formula (4)-1 was used as a lubricant coating.

A magnetic tape was produced in the same manner as in Example 1, except that 0 and 1 wt% IPA solutions of the organic compounds were used.

(Example 11) A magnetic tape was produced in the same manner as in Example 1, except that a 0.1 vt% IPA solution of an organic compound represented by the following structural formula (5)-2 was used as a lubricant coating.

(Example 9) A magnetic tape was produced in the same manner as in Example 1, except that a 0.1 vt% IPA solution of an organic compound represented by the following structural formula (4)-2 was used as a lubricant coating.

(Example 12) A magnetic tape was produced in the same manner as in Example 1, except that a 0.1 wt % IPA solution of an organic compound represented by the following structural formula (6)-1 was used as a lubricant coating.

(Example 10) As a lubricant paint, the organic compound represented by the following structural formula (5)-1 (Example 13) As a lubricant paint, an organic compound Q represented by the following structural formula (6)-2, 1 wt% IPA solution A magnetic tape was produced in the same manner as in Example 1, except that .

(Example 14) The organic compound represented by the structural formula (4)-1 used in Example 8 and perfluoropolyether [Fomblin Z-AM20 manufactured by Montegisson
01] and 1% ZS mixed at a weight ratio of 1:1.
A magnetic tape was produced in the same manner as in Example 1, except that 90 solution was used.

(Comparative Example 1) As the lubricant paint in Example 1, Fonblin Z-
A magnetic tape was produced in the same manner as in Example 1, except that a 0.1% AM2001+1% ZS90 solution was used.

(Comparative Example 2) As the lubricant paint in Example 1, 0 stearic acid
A magnetic tape was produced in the same manner as in Example 1, except that a 1 vt% IPA solution was used.

(Comparative example 3) Except that the formation of the lubricating layer in Example 1 was omitted.

A magnetic tape was produced in the same manner as in Example 1.

The magnetic tapes prepared in Examples 1 to 14 and Comparative Examples 1 to 3 were assembled into an 8-pin VTR cassette half with a 90-minute specification, and a running test was conducted on an actual machine. The evaluation was the total running time during which the reproduction output decreased by 6 dB (output deterioration time T1), and the time during which the output decreased by 6 dB during still reproduction (still life T2).

and the degree of tape squeal. The evaluation criteria for tape squealing was divided into three levels: o: no squealing, Δ: sometimes squealing, and x: squealing. In addition, the stability of the magnetic tape over time was evaluated by examining the coefficient of friction of the magnetic recording layer against a stainless steel (SUS) pin immediately after the magnetic tape was prepared and after being left at 60° C. and 90% RH for two weeks. The results are shown in Table 1.

As is clear from Table 1, the magnetic tapes obtained in Examples 1 to 14 of the present invention have longer durability than the magnetic tapes of Comparative Examples 1 to 3, both in terms of deterioration time T□ and still life T2. This shows that it is a good magnetic recording medium with excellent properties, low tape squeal, and no change in friction coefficient. On the other hand, the magnetic tape of Comparative Example 1 has relatively good durability but has a lot of tape squeal, the magnetic tape of Comparative Example 2 has significantly poor corrosion resistance, and the magnetic tape of Comparative Example 3 has significantly poor durability. It shows. therefore.

According to the present invention, it is possible to realize a magnetic recording medium that has good running properties, good corrosion resistance, and excellent durability.

〔Effect of the invention〕

As explained in detail above, the magnetic recording medium having the lubricating layer of the present invention has long output deterioration time and still life, is excellent in corrosion resistance and durability, has almost no change in friction coefficient, and has running stability with little tape squeal. A highly reliable magnetic recording medium with excellent properties can be obtained.

Representative Patent Attorney Junnosuke Nakamura

Claims (1)

[Claims] 1. In a magnetic recording medium having a magnetic recording layer formed directly or via an underlayer on a non-magnetic substrate, the following structural formula (1) or ( 3) A magnetic recording medium comprising a lubricating layer containing at least one compound selected from the organic compounds shown in item 3). ▲There are mathematical formulas, chemical formulas, tables, etc.▼......(1) ▲There are mathematical formulas, chemical formulas, tables, etc.▼......(2) ▲There are mathematical formulas, chemical formulas, tables, etc.▼......(3) (Formula (wherein, R represents an alkyl group having 8 or more carbon atoms, R_F represents a perfluoroalkyl group having 4 or more carbon atoms, and n represents an integer of 0 to 3.) 2. Directly or with an underlayer on the nonmagnetic substrate. In the magnetic recording medium having a magnetic recording layer formed through the magnetic recording layer, at least one compound selected from organic compounds represented by the following structural formulas (4) to (6) is added on the magnetic recording layer. A magnetic recording medium characterized by being provided with a lubricating layer containing the lubricating layer. ▲There are mathematical formulas, chemical formulas, tables, etc.▼......(4) ▲There are mathematical formulas, chemical formulas, tables, etc.▼......(5) ▲There are mathematical formulas, chemical formulas, tables, etc.▼......(6) (Formula (wherein, R represents an alkyl group having 8 or more carbon atoms, R_F represents a perfluoroalkyl group having 4 or more carbon atoms, and n represents an integer of 0 to 3.) 3. Claims 1 or 2 Structural formula (1) of
A magnetic recording medium, wherein R in the organic compound represented by (6) is an unbranched linear alkyl group. 4. A magnetic recording medium, wherein R in the organic compound according to claim 1, 2, or 3 has 1 to 4 double bonds. 5. A magnetism characterized in that in the organic compound according to claim 1, 2, 3, or 4, some or all of the hydrogens of R are an alkyl group substituted with fluorine. recoding media. 6. The magnetic recording medium according to any one of claims 1 to 5, wherein the magnetic recording layer is made of an elemental metal such as Co (cobalt), Fe (iron), or Ni (nickel) or any of the above metals. A magnetic recording medium characterized in that it is a ferromagnetic metal thin film made of at least one metal or alloy selected from among alloys as a main component. 7. The magnetic recording medium according to claim 6, wherein the ferromagnetic metal thin film forming the magnetic recording layer is made of a simple metal of Co or an alloy mainly composed of Co, and the surface of the magnetic recording layer, that is, the magnetic Between the recording layer and the lubricating layer, Co
A magnetic recording medium characterized by forming a passive layer.