JPS63167413A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To provide a magnetic recording medium which does not form rust on the surface of a magnetic layer and decreases deterioration of the magnetic characteristics with age by forming a specific rust inhibitor layer and lubricating agent layer successively on a thin ferromagnetic metallic film formed on a nonmagnetic base. CONSTITUTION:N-substd. perfluoroalkane amide is coated as a rust inhibitor on the thin ferromagnetic metallic film of the magnetic recording medium formed with the thin ferromagnetic metallic film as the magnetic layer on the nonmagnetic base and the lubricating agent layer is further formed thereon. The N-perfluoroalkane amide is the compd. expressed by the general formula CnF2n+1CONHR (R is a hydrocarbon group, n>=3). The formation of the rust on the surface of the thin ferromagnetic metallic film is thus prevented even at and under a high temp. and high humidity. The deterioration of the magnetic characteristics with age in coercive force and saturation magnetization quantity is decreased. The magnetic recording medium having a small coefft. of dynamic friction and excellent running stability and durability is thus obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a so-called magnetic layer in which a ferromagnetic metal thin film is formed as a magnetic layer on a non-magnetic support by vacuum thin film forming techniques such as vacuum evaporation and sputtering. The present invention relates to a ferromagnetic metal thin film type magnetic recording medium.

[Summary of the invention]

The present invention provides a magnetic recording medium in which a ferromagnetic metal thin film is formed as a magnetic layer on a non-magnetic support, in which an N-substituted perfluoroalkanamide is coated as a rust preventive agent on the ferromagnetic metal thin film that is the magnetic layer. However, by forming an additional lubricant layer on top of the lubricant layer, there is almost no rust on the magnetic layer surface even under high temperature conditions, and there is little change in magnetic properties such as coercive force and saturation magnetization. The aim is to provide a magnetic recording medium with excellent runnability and durability.
be.

[Conventional technology]

Conventionally, as a magnetic recording medium, r
γ-Fez○3°Fe3 containing FexOs, Co
F 8204,7 F e z containing O4,co
○.

and F2O3, ferromagnetic compounds containing Co, oxide ferromagnetic powders such as CrO□, or Fe, Co, N! A powder magnetic material such as an alloy magnetic powder whose main components are vinyl chloride-vinyl acetate copolymer,
Coating-type magnetic recording media, which are manufactured by coating and drying a magnetic paint dispersed in an organic binder such as polyester resin or polyurethane resin, are widely used.

On the other hand, with the increasing demand for high-density magnetic recording, ferromagnetic metal materials such as Co-Ni alloys have been developed using plating and vacuum GT film forming techniques (vacuum evaporation, sputtering, ion blating, etc.). A so-called ferromagnetic metal thin film type magnetic recording medium, which is directly deposited on a non-magnetic support such as a polyester film or a polyimide film, has been proposed and is attracting attention. A magnetic recording medium made of this ferromagnetic metal 1 not only has excellent coercive force and squareness, and has excellent electromagnetic conversion characteristics at short wavelengths, but also has an extremely thin magnetic layer, making it possible to record It has a number of advantages, including extremely low thickness loss during demagnetization and reproduction, and the ability to increase the packing density of magnetic material because there is no need to mix a non-magnetic organic binder into the magnetic layer. There is.

However, since the magnetic layer of the above-mentioned ferromagnetic metal thin film type magnetic recording medium is made of metal, the surface of the magnetic layer tends to corrode during storage, especially when left under high temperature or high humidity. There was a problem that magnetic properties such as saturation magnetization deteriorated over time.

In addition, in the above-mentioned ferromagnetic metal thin film type magnetic recording medium, since the surface of the magnetic layer has extremely good smoothness, the substantial contact area becomes large, making it easy for 'a adhesion phenomenon (so-called sticking) to occur. There are many drawbacks in terms of durability, running performance, etc., such as a large coefficient of friction, and improvement thereof is also a problem.

[Problem that the invention seeks to solve]

The present invention provides a ferromagnetic metal thin film type magnetic recording medium that hardly generates grains on the surface of the magnetic layer even at high temperatures or high temperatures, has little change in magnetic properties over time, and has excellent running properties and durability. The aim is to solve the above-mentioned problems.

[Means for solving problems]

As a result of intensive research to achieve the above-mentioned object, the inventors of the present invention have found that by coating an N-substituted perfluoroalkanamide on a ferromagnetic metal thin film and forming a lubricant layer on top of it, a good The present invention has been completed by discovering that a ferromagnetic metal T formed on a non-magnetic support has a rust-preventing effect and is excellent in runnability and durability.
! It is characterized in that an N-substituted perfluoroalkanamide is applied onto the peritoneum, and a lubricant layer is sequentially formed on top of the N-substituted perfluoroalkanamide.

The N-substituted perfluoroalkane amide used as a rust inhibitor in the present invention has the general formula %() (wherein R is a hydrocarbon group and n is an integer of 3 or more.) The compound shown is

Here, the hydrocarbon group R in the alkane moiety in the above formula (1) may be linear or branched, or may contain an alicyclic or aromatic ring, especially one containing a double bond. is more preferable.

The N-substituted perfluoroalkane amide represented by the above formula (I) can be easily synthesized by the synthesis method represented by the following formula (A).

... (A) Regarding the above perfluorocarboxylic acid chloride, the method of LHauptschein [Journal of American Chemical Society 75]
B? (1953)) or can be synthesized by the method proposed by the present inventor in Japanese Patent Application No. 61-26577. For example, in Japanese Patent Application No. 61-26577, the corresponding perfluorocarboxylic acid (C, IF, 1
．． , C00H) with thionyl chloride (SOCh) in the presence of dimethylformamide (DMF) to chlorinate the reaction formula.

DMF... (B) (In the formula, n represents an integer.) In addition, for long-chain amines, the corresponding carboxylic acid is converted into a chloride using thionyl chloride or oxalyl chloride, and then the acid is reacted with ammonia. It can be obtained by reducing the amide with lithium aluminum hydroxide.

(For example, the method of Nagase et al., Agriculture Biological Chemistry 47 5
3 The above-mentioned rust preventive can be applied to the ferromagnetic metal thin film by diluting the rust preventive in an appropriate solvent and applying it to the surface of the ferromagnetic metal thin film, or by applying the vapor of the rust preventive to the ferromagnetic metal thin film. Various methods can be used, such as applying it to the surface of a thin film.

The magnetic recording medium on which the rust preventive layer has been formed in this manner further has a lubricant layer containing a lubricant as a main layer above the rust preventive layer. By forming a lubricant layer, the wear resistance, running properties, and durability of the magnetic recording medium are significantly improved. Therefore, in combination with the corrosion-resistant effect of the rust preventive layer made of the N-substituted perfluoroalkanamide, the characteristics of the magnetic recording medium can be improved.

As shown in FIG. 1, a magnetic recording medium on which a rust preventive layer and a lubricant layer are formed as described above includes a nonmagnetic support (1), a ferromagnetic metal thin film (2), and a rust preventive layer (4). ), lubricant layer (3)
It has a structure in which the layers are sequentially laminated in this order. That is, it has a two-layer structure in which a layer having a rust-preventing effect and a layer having a lubricating effect are separately laminated.

Here, the rust preventive agent IJ (4) may be formed by depositing only the above-mentioned N-substituted perfluoroalkanamide, but
If necessary, appropriate amounts of other rust preventive agents, extreme pressure agents, etc. may be added. The above rust preventive agent N (4) is applied to a ferromagnetic metal thin film (2
), the coating amount is equal to that of the magnetic recording medium 1.
- Preferably about 0.5 to 100 ■/per, and 1 to 20 ■/
M is more preferable. If the coating amount is too small, the effect of improving corrosion resistance will not be apparent, while if it is too large, a sticking phenomenon will occur between the sliding member and the ferromagnetic metal thin film, resulting in poor running properties.

Other rust preventives that can be used in the rust preventive layer (4) may include any rust preventive agent that is normally used as a rust preventive agent for this type of magnetic recording medium, such as phenols. , naphthols, quinones, diaryl ketones, heterocyclic compounds containing a nitrogen atom, heterocyclic compounds containing an oxygen atom, heterocyclic compounds containing a sulfur atom, compounds having a mercapto group, thiocarboxylic acids or their salts, thiazole compounds, etc. can be mentioned. Specific examples are as follows.

First, the above-mentioned phenols include dihydric phenols, alkylphenols, and nitrosophenols.

The dihydric phenol mentioned above is hydroquinone.

Pure phenols such as resorcinol and catechol, and alkylamino, nitro, and halogeno substituted products thereof, such as 2-methylhydroquinone, 4-methylresorcinol, 5-methylresorcinol, 4-methylpyrocatechol, 2,5-dimethylhydroquinone , 4,6-dimethylresorcinol.

2.5-dimethylresorcinol, 2-isopropyl-
Examples include 5-methylhydroquinone + 2-tart-butylhydroquinone, 215-di-tert-butylhydroquinone, 4-tert-butylcatechol, 2-amylsorcinol, 2-resorcinol, 2°5-dichlorohydroquinone, and the like. The above alkylphenol refers to an alkyl substituted product of -valent phenol,
For example, 0-cresol.

m-cresol, p-cresol, 0-ethylphenol, m-ethylphenol, p-ethylphenol, 2
．． 3-dimethylphenol, 2,5-dimethylphenol, 2,6-dimethylphenol.

3.4-dimethylphenol, 3,5-dimethylphenol, 2,4.6-)dimethylphenol, 2
, 4.5-trimethylphenol, 5-isopropyl-
2-Methylphenol, p-tert-butylphenol, 2,6-tert-butyl-p-cresol.

Examples include 4,4'-methylenebis-2,6-tert-butylphenol, 2,6-dimethyl-4-tert-butylphenol, and 2,4,6-tri-tert-butylphenol.

Examples of the above nitrosophenols include 4-nitroso-2-methoxy-1-phenol, 4-nitroso-2
-Ethoxy-1-phenol, 6-nitroso-〇-cresol, 4-nitroso-m-cresol, 0-nitrosophenol, 2-nitrolaphenol. Examples include 2-nitrosoresorcin, 4-nitrosoresorcin, p-nitrosophenol, and the like.

Next, the naphthols mentioned above include α-naphthol, β-naphthol,
- Naphthol, 1,2-naphthalenediol.

1.3-naphthalenediol, 1,4-naphthalenediol, 1,5-naphthalenediol, 1.7-naphthalenediol, 1.8-naphthalenediol, 2.3-naphthalenediol, 1,4.5-naphthalenediol , 1,2゜5.8-Naphthalenetetraol and other pure naphthols, and nitro, nitroso, amino, halogeno i! tA naphthols, such as 1-chloro-2-naphthol, 2°4-dichloro-1-naphthol, 1-nitro-2-naphthol, 1,6-sinitro-2-naphthol, 1-nitroso-2-naphthol, 2- Nitroso-1
-naphthol, 1-amino-2-naphthol, and the like.

The above quinones include p-benzoquinone, 0-benzoquinone, 1.2-naphthoquinone, 1.4-naphthoquinone, 2.6-naphthoquinone, anthraquinone, 9゜10-
Quinones without substituents such as phenanthrenequinone and diphenoquinone; methylquinones such as methyl-p-benzoquinone, 2,3-dimethyl-p-benzoquinone, 2-methyl-1,4-naphthoquinone and 2-methylanthraquinone;2. 5-dihydroxy-p-benzoquinone 5-tetrahydroxy-p-benzoquinone, 5-hydroxy-1,4
-naphthoquinone, 2.3-dihydroxy-1,4-naphthoquinone, 5.8-dihydroxy-1,4-naphdoquinone, 2-hydroxyanthraquinone, 1゜2-di-droxyanthraquinone, 1,2.3-1- Hydroxyquinones such as lihydroxyanthraquinone, 1.2.4-)lihydroxyanthraquinone, 1,2.5-trihydroxyanthraquinone, 1,2.6-)lihydroxyanthraquinone, 1゜2.7-)lihydroxyanthraquinone 2-aminoanthraquinone, 1.2
-Aminoquinones such as diaminoanthraquinone, nitroquinones such as 1-nitroanthraquinone and 1,5-dinitroanthraquinone, and halogenoquinones such as 2,6-dichloro-p-benzoquinone, tetrachloro-p-benzoquinone, and tetrabromo-p-benzoquinone. , or 2
Quinones having more than one substituent, such as 2,5-dichloro-3,6-dihydroxy-p-benzoquinone, 1-
Examples include methyl-2-hydroxy-1,4-naphthoquinone.

Examples of the diaryl ketone include benzophenone and derivatives thereof, such as benzophenone, 4-methylbenzophenone, 3-methylbenzophenone, 3.4
-dimethylbenzophenone, 4゜4'-dimethylbenzophenone, 3.4'-dimethylbenzophenone, 4-
Alkyl substituted products such as ethylbenzophenone, 4-hydroxybenzophenone.

4.4”-dihydroxybenzophenone, 2,3.4
-) Hydroxybenzophenones such as dihydroxybenzophenone, 2.4-dihydroxybenzophenone, 2.2', 5.6'-tetrahydroxybenzophenone, 2.3', 4.4', 6-pentahydroxybenzophenone, 4-amino Benzophenone, aminobenzophenones such as 4'-diaminobenzophenone, or benzophenones having two or more substituents, such as 4-methoxy-2-hydroxybenzophenone,
2.2'-dihydroxy-4-methoxybenzophenone and the like can be mentioned.

Examples of the nitrogen atom-containing heterocyclic compound include acridine, 2.2°, 2-terpyridylneocuproine, 2.2
"-dipyridylbenzotriazole, 5-methylbenzotriazole, bathophenandroline, 1,10-phenanthroline, aldehyde collidine, benzylpyridine, phenylpyridine, quinazoline, 2-heptadecylimidazole, etc., as well as compounds having a phenolic hydroxyl group , for example 4-(2-pyridylazo)-resorcin 1-(
Compounds having a carboxyl group such as 2-pyridylazo)-2-naphthol, 4-quinolitool, 4-methyl-2-quinolitool, 8-quinolitool, quinolinediol, such as kynurenic acid, acridic acid, atophane, kirnadic acid, cinchoninic acid, Isonicotine! , 2.5-
Compounds having an amino group or imino group such as pyridinedicarboxylic acid and quinic acid, such as 2-aminobenzimidazole and 5-amino-IH-tetrazole.

5-amino-I H-1,2,4-triazole, adenine, guanine, luminol, 2-hydrazinoquinoline, thiamine, etc. Compounds having a carbonyl group, such as boflavin, theobromine, allantoin, alloxan, 2-thiobarbylic acid , bioluric acid, isatin, hydantoin, thymine, barbylic acid, orotic acid, uracil, succinimide, taleatinin, 2-pyrrolidone, and the like.

Examples of the above-mentioned heterocyclic compounds containing an oxygen atom include tocopherol, morin, quercetin, ascorbic acid, anhydride 1.
Examples include 8-naphthalic acid, resorufin, kojic acid, dehydroacetic acid, oxazole, 3-aminophthalimide, 4-aminophthalimide, uridine, thymidine, guanosine, isatoic anhydride, and the like.

Examples of the above-mentioned heterocyclic compounds containing a sulfur atom include sulfolane, 3-hydroxysulfolane, 3-methylsulfolane,
Sulfolene, 3-hydroxysulfolene, 3-methylsulfolene, rhodanine, 3-aminorhodanine, thiazoline-4-carboxylic acid, 4H-1,4-thiazine, biotin, 3,6-thioxanthine diamine, 3,6 -thioxanthin diamine-10,10-dioxide and the like.

Examples of the compound having a mercapto group include 2-benzoxazolethiol and thiophenol.

Thiosalicylic acid, propanethiol, thiouracil, 2
, 3-quinoxalinedithiol, dithizone, thioxin, 2-benzimidazolethiol.

6-thioguanine, 5-nitro-2~benzimidazo↓
Ruthiol, 5-amino-1,3,4-thiazole-2
-Thiol and the like.

Examples of the thiocarboxylic acid or its salt include sodium diethyldithiocarbamate, ethanethioic acid, rubeanic acid, thioacetamide, ethanedithioic acid, and the like.

The above thiazole compounds include bismuthiol■,
Diazosulfide, azosulfime, 1゜3.4-thiadiazole, bismuthiol, biazthiol, benzothiazole, 2-methylbenzothiazole, 2-(p-
aminophenyl)-6-methylbenzothiazole, 2-
Mercaptobenzothiazole.

Examples include benzothiazoline, 2-benzothiazoline, benzothiazolone and the like.

In addition, when the extreme pressure agent added to rust preventive agent N (4) makes partial metal contact in the boundary lubrication area, it reacts with the metal surface due to the accompanying frictional heat, forming a reaction product film. This is a boron-based scratching agent that acts to prevent friction and wear.

Phosphorus-based extreme pressure agents, sulfur-based extreme pressure agents, halogen-based extreme pressure agents, residual metal-based extreme pressure agents, composite extreme pressure agents, and the like are known.

Specifically, examples of the boron-based scratching agent include tributyl borate, triotadecyl borate, triphenyl borate, tritolyl borate, triethyl borate, tripropyl borate, trimentyl borate, etc. .

The above-mentioned phosphorus-based extreme pressure agent includes tributyl phosphate,
Trioctyl phosphate, tri-2-ethylhexyl phosphate, trilauryl phosphate Trioleyl phosphate, dibutyl phosphate, dioctyl phosphate Di-2-ethylhexyl phosphate, dilauryl phosphate, dioleyl phosphate, etc. phosphate esters, tributyl phosphite, Trioctyl phosphite, tri-2-ethylhexyl phosphite 1 trilauryl phosphite, trioleylphosphite, dibutyl phosphite, dioctyl phosphite, di-2-ethylhexyl phosphite, dilauryl phosphite, dioleyl phosphite Phosphite esters such as dibutyl phosphate butylamine salt, dibutyl phosphate octylamine salt, dibutyl phosphate stearylamine salt, dioctyl phosphate butylamine salt, dioctyl phosphate octylamine salt, dioctyl phosphate laurylamine salt.

Dioctyl phosphate stearylamine salt, di-2-
Ethylhexylphosphate butylamine salt, di-2-
Ethylhexylphosphate octylamine salt, G2
-Ethylhexylphosphate laurylamine salt, di-2-ethylhexylphosphate stearylamine salt,
Dilaurylphosphate butylamine salt 2 Dilaurylphosphate octylamine salt, dilaurylphosphate laurylamine salt, dilaurylphosphate stearylamine salt, dioleylphosphate butylamine salt,
Dioleyl phosphate octylamine salt, dioleyl phosphate laurylamine salt.

Examples include phosphate ester amine salts such as dioleyl phosphate stearyl amine salt.

The above-mentioned sulfur-based extreme pressure agents include mineral oils with unsaturated bonds such as sulfurized whale oil and sulfurized dipentene, sulfurized oils and fats produced by adding sulfur to fats and oils and fatty acids, and heating them, dibenzyl disulfide, and disulfide. diphenyl, di-t disulfide
-butyl 5 disulfide di-5ee-butyl, disulfide di-n-
Disulfides such as butyl, octyl disulfide, diethyl disulfide, benzyl sulfide, diphenyl sulfide, divinyl sulfide, dimethyl sulfide, diethyl sulfide, di-1 sulfide
- Monosulfides such as butyl, di-5ec-butyl sulfide, di-n-butyl sulfide, polysulfides such as dimethyl trisulfide, di-t-butyl trisulfide, di-1-nonyl polysulfide, and olefin polysulfide, general formula % Examples include thiocarbonate represented by the formula %([) ([) (wherein R represents a hydrocarbon group)], elemental sulfur, and the like.

The halogen-based extreme pressure agent is allyl bromide.

Bromine compounds such as octadecyl bromide, cyclohexyl bromide, stearyl bromide, benzyl bromide, io-1 compounds such as benzyl iodide, allyl iodide, butyl iodide, octadecyl iodide, cyclohexyl iodide, hexachloroethane, monochloroethane .

Examples include chlorine compounds such as chlorinated paraffin, chlorinated diphenyl, chlorinated fats and oils, methyl trichlorostearate, pentachloropentadienoic acid, esters of hexachloronaphthenic acid compounds, and imide derivatives of hexachloronaphthenic acid compounds.

The organometallic extreme pressure agents include zinc diisobutyldithiophosphate, zinc isobutylpentyldithiophosphate, zinc isopropyl-1-methylbutyldithiophosphate, zinc isobutylnonylphenyldithiophosphate, zinc isobutylheptylphenyldithiophosphate, and zinc diheptylphenyldithiophosphate. Zinc, dinonylphenyl dithiophosphate zinc,
thiophosphates such as molybdenum dithiophosphate,
Zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, zinc ethylphenyldithiocarbamate.

Thiocarbamates such as zinc dibenzyldithiocarbamate, zinc dimethyldithiocarbamate, copper plated dimethyldithiocarbamate, iron dimethyldithiocarbamate, selenium diethyldithiocarbamate, silver diethyldithiocarbamate, metal alkyldithiocarbamates such as molybdenum and antimony, etc. Can be mentioned.

Examples of the composite extreme pressure agent include dialkylthiophosphate amines such as di-2-ethylhexylthiophosphate amine, propyl chloride, propyl bromide, propyl iodide, butyl chloride,
Phosphate esters of alkyl halides such as butyl bromide phosphate, butyl iodide phosphate, etc.
In addition to chloronaphsanthate, thiophosphates represented by the general formula % () (wherein R in each general formula represents a hydrogen atom, an alkyl group, an alkenyl group, or an aryl group) , in which R represents a hydrogen atom, an alkyl group, an alkenyl group, or an aryol group) are highly effective.

The above-mentioned extreme pressure agents may be used alone, but it is also possible to use a mixture of two or more types.

On the other hand, the lubricant layer (3) is formed by applying a lubricant, and if necessary, an extreme pressure agent may be added thereto. The weight shall be within the range of %. The above-mentioned rust preventive agent may be added to the lubricant N(3) to further improve the rust preventive effect. The lubricant layer (3
) is coated on the rust preventive layer (4), the coating amount is preferably about 0.5 to 100 cm per 1 of the magnetic recording medium, and more preferably 1 to 20 cm per square. preferable.

If the coating amount is too small, the lubricating effect will not be apparent, while if it is too large, a sticking phenomenon will occur between the sliding member and the ferromagnetic metal thin film, resulting in poor running performance.

As the lubricant that can be used in the lubricant layer (3), conventionally known ordinary lubricants can be used, such as fatty acids or metal salts thereof, fatty acid amides, fatty acid esters, fatty alcohols or alkoxides thereof, and fatty amines. , polyhydric alcohols, sorbitan esters, mannisotan esters, sulfurized fatty acids, aliphatic mercaptans, modified silicone oils, perfluoroalkyl ethylene oxides, perfluoropolyethers, higher alkyl sulfonic acids or their metal salts, perfluoroalkyl sulfonic acids or its ammonium salt or its metal salt, perfluoroalkylcarboxylic acid or these metal salts (carboxylic acid perfluoroalkyl ester or perfluoroalkylcarboxylic acid ester, etc. are exemplified, and these are used alone or in a mixture of two or more types) Of course, the usable lubricants are not limited to these, and it goes without saying that any conventionally known lubricants can be used.

In particular, perfluoropolyethers, perfluoroalkyl carboxylic acid esters, and perfluoroalkyl carboxylic acid esters have excellent low-temperature properties, so by using these as part of the lubricant, the operating temperature range can be expanded.

The above-mentioned perfluoropolyethers include -aCF, 云OCF (CF s) CF x→=rmoOCF a-
T→CF s, polyether represented by the general formula % (X+ 3', qr in the above general formula are integers, preferably within the range of 40 to 500), These polyethers have hydroxyl, carboxyl, and phosphoric acid groups at the molecular ends.

Examples include those into which polar groups such as sulfonic acid groups, salts thereof, and ester groups have been introduced, and have excellent lubricity and oxidation resistance. Specifically, examples include Fonprin, a product manufactured by Montegisson, and Talite Sox, a product manufactured by DuPont.

The above carboxylic acid perfluoroalkyl ester has the general formula (however, in the above general formula, n≧4, m≦2n+1,
j≧0, k≧3. ) is a compound represented by Here, the number of n in the aliphatic hydrocarbon group (-C, lH,) of the carboxylic acid may be 4 or more, but preferably 12 or more.

Further, this aliphatic hydrocarbon group may be either saturated or unsaturated, and may be linear or have a side chain.

Specifically, for example, oleic acid pentadecafluorooctyl ester, lylunic acid pentadecafluorooctyl ester, linoleic acid pentadecafluorooctyl ester, linoleic acid nonadecafluorodecyl ester, isostearic acid nonadecafluoroodecyl ester, butanoic acid pentadeca Examples include fluorodecyl ester.

The above-mentioned perfluoroalkyl carboxylic acid ester represents a hydrocarbon group having a general formula number of 1 to 25. ) is a compound represented by

Specifically, for example, nonadecafluorodecanoic acid isostearyl ester, pentadecafluorooctanoic acid isostearyl ester, pentadecafluorooctanoic acid isononyl ester, pentadecafluorooctanoic acid sulfur ester, nonadecafluorooctanoic acid sulfur ester , nonadecafluorodecanoic acid runyl ester, and the like.

In addition, in order to prevent uneven wear of the magnetic head due to sliding friction between the magnetic head and the magnetic recording medium, amine borane may be added.The amount of amine borane added is within the range of 10 to 30% by weight of the lubricant. do.

Examples of amine borane that can be used include: ■ dimethylamine borane ((C1,) 3N-BHi)■Triethylamineborane ((CzHs)J-BHs)■t-butylamineporane ((Cut) scNHg' BHi)■
N,N-dimethylanilineborane (C-RsN(CtH
%) Proverb 88. ) @'; ia 7'o hill 7 mi 7 ho-y
C ((CIliLCH) tNt811s) ■ Ammoniaporane (NH,.BH3) [Phase] Monomethylamine borane ((Ct13)N)lz.B11. ) etc.

In addition to the above-mentioned lubricant and amine borane, an extreme pressure agent and a rust preventive agent may be added to the above-mentioned lubricant N(3) as necessary. As the extreme pressure agent and rust preventive agent, the same ones as those that can be added to the above-mentioned rust preventive agent N(4) can be used, and they may be appropriately selected so as to obtain predetermined characteristics.

The magnetic recording medium to which the present invention is applied is one in which a ferromagnetic metal thin film is provided as a magnetic layer on a non-magnetic support, and the material for the non-magnetic support may include polyesters such as polyethylene terephthalate, Polyolefins such as polyethylene and polypropylene, cellulose derivatives such as cellulose triacetate, cellulose diacetate, and cellulose acetate butyrate, vinyl resins such as polyvinyl chloride and polyvinylidene chloride, polycarbonate,
Examples include plastics such as polyimide and polyamideimide, light metals such as aluminum alloys and titanium alloys, and ceramics such as alumina glass.

The forms of this non-magnetic support include film, sheet,
It may be a disk, card, drum, etc.

The surface roughness of the non-magnetic support may be controlled by forming one or more types of protrusions such as mountain-like protrusions and 9-grain protrusions on the surface of the non-magnetic support.

For example, the above-mentioned mountain-like protrusions have a particle size of 5 when forming a polymer film.
It is formed by internally adding 0.00 to 3000 particles, and the height from the surface of the polymer film is 100.
~1000 people, density approximately lXl0'~l0XIO'
pieces/1m”.The inorganic fine particles used to form the mountain-like protrusions include calcium carbonate (CaCO
S), silica, alumina, etc. are suitable.

The wrinkle-like protrusions are undulations formed by, for example, applying and drying a dilute solution of resin using a specific mixed solvent, and the height thereof is 0.01 to 10 μm, preferably 0.
．． 03~0.5μm, the shortest distance between protrusions is 0.1~20
Let it be μm. Examples of resins used to form these wrinkle-like projections include saturated polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyamides, polystyrene, polycarbonates, polyacrylates, polysulfones, polyethersulfones, polyvinyl chloride, polyvinylidene chloride, and polyvinyl butyral. A single substance, a mixture, or a copolymer of various resins such as polyphenylene oxide, phenoxy resin, etc., and those having a soluble solvent are suitable. Then, a solvent that is a poor solvent for the resin and has a boiling point higher than the good solvent is added in an amount of 10 to 100 times the amount of the resin to a solution in which these resins are dissolved in the good solvent and the resin concentration is 1 to 11,000 pp. By applying and drying the solution on the surface of a polymer film, an "i1 layer" having very fine wrinkle-like irregularities can be obtained.

The granular protrusions are formed by attaching organic ultrafine particles such as acrylic resin or inorganic fine particles such as silica or metal powder in a spherical or semispherical shape. The height of this granular protrusion is
50 to 500 people, density 1XIO' to 50X10b/la'' i degree tossle.

The surface properties of the ferromagnetic metal thin film that is the magnetic layer can be controlled by forming at least one type of these protrusions, but the effect is enhanced by combining two or more types. By forming the protrusions and the protrusions, durability and running properties are greatly improved.

In this case, the overall height of the protrusion is 100 to 200
The density is preferably within the range of 0 people, and the density is ln+
It is preferable that the average number of particles per unit is 1 x 105 to 1 x 10?.

Further, the ferromagnetic metal thin film that is the magnetic layer is formed as a continuous film by a vacuum thin film forming technique such as a vacuum evaporation method, an ion blating method, or a sputtering method.

In the vacuum evaporation method described above, a ferromagnetic metal material is evaporated by resistance heating, high frequency heating, electron beam heating, etc. under a vacuum of 10-' to 10-'' Torr, and the evaporated metal (
Generally, in order to obtain a high coercive force, an oblique evaporation method is employed in which the ferromagnetic metal material is deposited obliquely to the substrate. or,
It also includes those in which the vapor deposition is performed in an oxygen atmosphere in order to obtain higher coercive force.

The above-mentioned ion brating method is also a type of vacuum deposition method, in which DC glow discharge and RF glow discharge are caused in an inert gas atmosphere of 10-4 to 10-' Torr, and the above-mentioned ferromagnetic metal material is evaporated during the discharge. It is to let them do so.

The above sputtering method uses 10-' to 10-' Torr.
A glow discharge is caused in an atmosphere mainly composed of argon gas, and the generated argon gas ions are used to knock out atoms on the target surface. method, or magnetron sputtering method using magnetron discharge.

In the case of this sputtering method, Cr or W is used.

A base film such as V may be formed in advance.

In any of the above methods, Bl, Sb, Pb, Sn, Ga, I
n.

By pre-depositing a base metal layer such as Cd, Ge, Si, TI, etc., and depositing the film in a direction perpendicular to the substrate surface, excellent magnetic properties can be achieved in an in-plane manner without magnetic anisotropy orientation. It is suitable for forming a layer, for example, into a magnetic disk.

When forming a metal magnetic thin film using such vacuum thin film forming technology, the ferromagnetic metal materials used include Fe,
In addition to metals such as Co and Ni, C.

-Ni alloy, Co-Pt alloy, Co-Ni-Pt alloy,
Fe-Co alloy, Fe-Ni alloy, Fe-Co-Ni alloy, Fe-Co-B alloy, Co-N1-Fe-B
Examples include alloys, Co-Cr alloys, and those containing metals such as Cr and A1. In particular, Co-C
When r-alloy is used, a perpendicularly magnetized film is formed.

The thickness of the magnetic layer formed by such a method is 0.
It is about 0.04 to 1 μm.

Furthermore, a so-called back coat layer may be formed on the surface of the nonmagnetic support opposite to the surface on which the magnetic layer is provided. The back coat layer is formed by coating the surface of the nonmagnetic support with a back coat paint in which a binder resin and a powder component are mixed and dispersed in an organic solvent.

Examples of the binder resin used in the back coat paint include vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, and acrylic ester-acrylonitrile copolymer. copolymer, thermoplastic polyurethane elastomer, polyvinyl fluoride, vinylidene chloride-acrylonitrile copolymer, butadiene-acrylonitrile copolymer,
Synthetic rubber resins such as polyamide resins, polyvinyl butyral, cellulose derivatives, polyester resins, and polybutadiene, phenolic resins, epoxy resins, polyurethane curable resins, melamine resins, alkyd resins, silicone resins, acrylic reaction resins, epoxy-polyamide resins, Nitrocellulose-melamine resins, mixtures of high molecular weight polyester resins and isocyanate prepolymers, mixtures of methacrylate copolymers and diisocyanate prepolymers, mixtures of polyester polyols and polyisocyanates, urea formaldehyde resins, low molecular weight glycols /polymeric diol/triphenylmethane triisocyanate mixture, polyamine resin, and mixtures thereof.

Alternatively, a binder resin having a hydrophilic polar group may be used to improve the dispersibility of the powder component.

Specifically, -go-maze-0503M, C00M, -
polyurethane resin into which a hydrophilic polar group selected from (OM') * (wherein M represents a hydrogen atom or an alkali metal, and M represents a hydrogen atom, an alkali metal or a hydrocarbon group); Polyester resins, vinyl chloride-vinyl acetate copolymers, vinylidene chloride copolymers, acrylic ester copolymers, butadiene copolymers, etc. can be used.

Various methods can be used to introduce the above-mentioned hydrophilic polar groups depending on the type of resin. For example, the following methods can be used to introduce the above-mentioned hydrophilic cold groups into polyurethane resins and polyester resins. Bye.

(11 A method in which the hydrophilic polar group is introduced in advance into a dibasic acid, polyol, etc. that is a raw material for polyurethane or polyester.

(2) A method in which an OH group is left at the terminal or side chain, and this OH group is modified with a compound having a hydrophilic polar group.

In the case of method (2), +21-1 a compound containing a hydrophilic polar group and a halogen (e.g. chlorine) in the molecule, and a polyfunctional polyol as a raw material, and an OH group at the end or side chain of the polymer chain. The remaining polyurethane resin or polyester resin is dissolved in a solvent such as dimethylformamide or dimethyl sulfoxide in which both components are soluble, and amines such as lysine, picoline, triethylamine, and epoxy compounds such as ethylene oxide and propylene oxide are dissolved. 0H in the presence of a dehydrochlorination agent such as
A method of introducing a hydrophilic polar group through a dehydrochlorination reaction between the group and chlorine.

+2+-2 A compound containing a hydrophilic polar group and an OH group in the molecule,
A method of reacting a polyurethane resin or a polyester resin in which an OH group remains at the end or side chain of a polymer chain via a diisocyanate compound.

There is.

In order to introduce a hydrophilic polar group into the copolymer-based binder resin, (3) a method of using a compound having a hydrophilic polar group and a copolymerizable double bond as a copolymerizable monomer.

(4) As a copolymerizable monomer, a compound having active hydrogen and a copolymerizable double bond is used, and the above active hydrogen is introduced into the side chain of the copolymer. A method of modifying with a compound having a group capable of reacting with.

(5) As a copolymerization monomer, use a compound having a group that can react with active hydrogen and a double bond that can be copolymerized, and introduce the group that can react with active hydrogen into the side chain of the copolymer. , a method of modification with a compound containing a hydrophilic polar group and the above-mentioned active hydrogen.

etc.

On the other hand, the above-mentioned powder component includes carbon-based fine powder for imparting conductivity (for example, furnace carbon, channel carbon, acetylene carbon, thermal carbon, lamp carbon, etc., among which furnace carbon and thermal carbon are used). ), inorganic pigments (α-Fe0OH, α-Ferns + C added to control surface roughness and improve durability)
rzOs + T iOg + ZnO, S r O+
SiO□Sing・21(go, AhOs・2SiO□
・21110, 3 units go・4510g ・HIO2M
gC0+ ・Mg(OH) t ・3HtOtAlzQ
+, CaC01+MgC0z, 5btOs, etc.).

Furthermore, as the organic solvent for the above-mentioned back coat paint,
Ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate,
Ethyl acetate, butyl acetate.

Ester solvents such as ethyl lactate and glycol monoethyl acetate, glycol ether solvents such as glycol dimethyl ether, glycol monoethyl ether, and dioxane, aromatic hydrocarbon solvents such as benzene, toluene, and xylene, and fats such as hexane and heptane. Group hydrocarbon solvents, methylene chloride, ethylene chloride,
Carbon tetrachloride, chloroform, ethylene chlorohydrin,
General-purpose solvents such as chlorinated hydrocarbon solvents such as dichlorobenzene can be used.

A lubricant may be used in combination with the above-mentioned back coat layer. In this case, there is a method of adding the lubricant internally to the back coat layer, or a method of depositing the lubricant on the bank coat layer. In any case, the above-mentioned lubricants include fatty acids,
Conventionally known lubricants such as fatty acid esters, fatty acid amides, metal soaps, fatty alcohols, paraffins, and silicones can be used.

Examples of these lubricants include fatty acids such as saturated fatty acids having 12 or more carbon atoms, such as lauric acid, myristic acid, valmitic acid, stearic acid, behenic acid, oleic acid, linoleic acid, and lylunic acid, or unsaturated fatty acids. Fatty acids can be used.

As the fatty acid ester, ethyl stearate, butyl stearate, amyl stearate, stearic acid monoglyceride, oleic acid monoglyceride, etc. can be used.

Examples of fatty acid amides include caproic acid amide, capric acid amide, lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, oleic acid amide,
linoleic acid amide, methylene bisstearic acid amide,
Ethylene bisstearamide, etc. can be used.

The metal soaps include the aforementioned fatty acids Zn, Pb, and N.
i.

Salts with Go+ Fe, AI, Mg+ Sr+ Cu, etc., or with sulfonic acids such as lauryl sulfonic acid, palmitylsulfonic acid, myristyl sulfonic acid, stearyl sulfonic acid, behenyl sulfonic acid, oleyl sulfonic acid, linolesulfonic acid, lilinsulfonic acid, etc. Salts with the above metals can be used.

As the aliphatic alcohol, cetyl alcohol, stearyl alcohol, etc. can be used.

As the paraffin, saturated hydrocarbons such as n-nonadecane, n-tridecane, and n-tocosan can be used.

As silicones, polysiloxanes in which hydrogen is partially substituted with alkyl groups or phenyl groups, and those modified with fatty acids, aliphatic alcohols, fatty acid amides, etc. can be used.

Furthermore, a lubricant similar to that of the top coat layer attached to the surface of the magnetic layer may be added.

[Effect]

As mentioned above, N
By depositing the -substituted perfluoroalkanamide, the formation of rust in the ferromagnetic metal thin film is prevented.

Furthermore, by forming a lubricant layer on top of the rust preventive layer, running properties and durability are improved.

〔Example〕

Hereinafter, specific examples of the present invention will be described, but the present invention is not limited to these examples.

A ferromagnetic metal fI film type magnetic recording medium was fabricated using an N-substituted perfluoroalkanamide.

Example 1 CO was deposited on a 14 μmpJ polyethylene terephthalate film by oblique evaporation to form a ferromagnetic metal thin film with a thickness of 1000 μm.

Next, on the surface of this ferromagnetic metal thin film, N-stearylpentadecafluorooctaneamide (CJ+5CON) I
After applying CIJ*y) in an amount of 5 g/I+, apply perfluoropolyether as a lubricant in an amount of 5 g/d, dry, and cut into 8 mm width. A sample tape was created.

Example 2 Co was deposited on a 14 μm fq polyethylene terephthalate film by oblique evaporation to form a ferromagnetic metal thin film with a thickness of 1000 μm.

Next, on the surface of this ferromagnetic metal thin film, N-lynylpentadecafluorooctaneamide (C?FISCONHC) was applied.
+sHi+) in an amount of 5#/M, then apply perfluoropolyether as a lubricant in an amount of 5#/I, dry it, cut it into 8mm width and make a sample tape. It was created.

Example 3 Co was deposited on a 14 μm thick polyethylene terephthalate film by oblique evaporation to form a 1000 μm thick ferromagnetic metal thin film.

Next, N-isostearylpentadecafluorooctaneamide (CJIscON) was applied on the surface of this ferromagnetic metal thin film.
Hisoc+ lH3? ) to a coating amount of 5*/n(), apply perfluoropolyether as a lubricant to a coating amount of 5*/d, dry it, cut it into 8 mm width and make a sample tape. It was created.

Example 4 CO was deposited on a 14 μm thick polyethylene terephthalate film by an oblique evaporation method to form a ferromagnetic metal fill film with a thickness of 1000 μm.

Next, on the surface of this ferromagnetic gold NTR film, Bentade was applied at a coating amount of 5 ■/n, and then perfluoropolyether was applied as a lubricant at a coating amount of 5 ■/M. After coating and drying, sample tapes were prepared by cutting into 8 mm width.

Example 5 Co was deposited on a 14 μm thick polyethylene terephthalate film by an oblique evaporation method to form a 1000 μm thick ferromagnetic metal thin film.

Next, on the surface of this ferromagnetic metal "Ti1M, N-nonylpentadecafluorooctaneamide CCqF l5cO
N) After applying ICJ+q) to a coating amount of 5 yt/d, apply perfluoropolyether as a lubricant to a coating amount of 5 yt/cd, dry, and cut into 8 mm width. A sample tape was created.

Example 6 CO was deposited on a 14 μm thick polyethylene terephthalate film by oblique evaporation to form a 1000 μm thick ferromagnetic metal thin film.

Next, after coating N-cyclohexylpentadecafluorooctaneamide on the surface of this ferromagnetic metal thin film,
The amount of perfluoropolyether applied as a lubricant is 5■
The sample tape was prepared by applying and drying the sample tape so as to give a width of 8 mm.

Example 7 Co was deposited on a 14 μm thick polyethylene terephthalate film by an oblique evaporation method to form a 1000 μm thick ferromagnetic metal thin film.

Next, this ferromagnetic metal mli! On the surface, N-oleyl nonadecafluorooctanamide (CJ I 9CON
After applying HC + eHss) at a coating amount of 5 ■/d, apply perfluoropolyether as a lubricant at a coating amount of 5 ■/d, drying, cutting into 8 mm width and making sample tape. It was created.

For each sample tape prepared, the initial holding power (
Hc+), saturation magnetization (Is+), and temperature 45°C,
Retention power (Ilcg) after being left under 80% relative humidity for one week
) and saturation magnetization! (1st) was measured, and the rate of change was determined according to the following formula. As Comparative Example 1, the rate of change was also investigated for a blank tape with only a lubricant layer and no rust preventive applied thereon. The results are shown in Table 1.

Rate of change in Hc = (Hcg-Hc+)/Hc, 'X100
(χ) Rate of change of Is - (Isz Is+)/Is+
X 100 (χ) Table 1 As is clear from the above table, each embodiment of the present invention is
It is extremely stable even when left for one week at a temperature of 45°C and a relative humidity of 80% RH, and the rate of change in He and Is
The rate of change in both values was extremely small, and no rust was observed. On the other hand, the tape of the comparative example without a rust preventive layer had a large change rate of He and a large change rate of Is (and had poor corrosion resistance, with a considerable amount of rust generated).

Next, the dynamic friction coefficient and shuttle durability were measured under conditions of a temperature of 25° C. and a relative humidity (RH) of 60% using the sample tapes produced in each of the above examples. This coefficient of dynamic friction was determined by using a guide pin made of stainless steel (SUS 304) and applying a constant tension of 5fl/se.
The test was conducted by feeding at a speed of c. In addition, the shuttle durability was evaluated by running the shuttle for 2 minutes each time, and determining the number of shuttle runs until the output decreased by 13 dB. Still durability was evaluated by evaluating the decay time for the output to -3 dB in a pause state. As Comparative Example 2, a blank tape without any rust preventive layer or lubricant layer was also measured. The measurement results are shown in Table 2.

(Left below) Table 2 As is clear from Table 2, the sample tapes of each example had a small coefficient of dynamic friction and extremely stable running properties.
Further, no damage was observed on the tape surface even after 100 reciprocating runs. Furthermore, the still durability was extremely good, and even after 150 shuttle runs, no decrease in output by 13 dB was observed. On the other hand, in the case of the comparative tape, the coefficient of friction increased as the number of reciprocating runs increased, and the running was unstable and the tape showed constant friction, and its durability was poor.

〔Effect of the invention〕

As is clear from the above description, in the present invention,
A rust preventive agent containing N-substituted perfluoroalkanamide as a main component is coated on the magnetic layer of a ferromagnetic metal thin film type magnetic recording medium, and a lubricant layer is provided on top of this, so it can withstand high temperatures or high humidity. Rust is prevented from forming on the surface of the ferromagnetic metal thin film that is the magnetic layer underneath, and there is little change in magnetic properties such as coercive force and saturation magnetization, and it has excellent running stability and durability with a small coefficient of dynamic friction. It can be used as a magnetic recording medium.

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view of a main part showing an example of the structure of a magnetic recording medium to which the present invention is applied. 1...Nonmagnetic support 2...Ferromagnetic metal thin film 3...Lubricant layer 4...Rust preventive layer

Claims (1)

[Claims] A magnetic recording medium comprising a ferromagnetic metal thin film formed on a non-magnetic support, and a rust preventive layer containing an N-substituted perfluoroalkanamide and a lubricant layer sequentially formed on the ferromagnetic metal thin film.