JPS62226422A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve running durability and friction resistance by holding a lubricating agent contg. a long-chain perfluoroalkyl carboxylate on a magnetic recording medium having a magnetic layer essentially consisting of magnetic powder and resin binder on a nonmagnetic substrate. CONSTITUTION:The magnetic recording medium is formed by providing the magnetic layer essentially consisting of the magnetic powder and resin binder on the surface of the nonmagnetic substrate 1. The layer contg. the lubricating agent shown by the dotted section is held on the magnetic layer. The layer contg. the lubricating agent may be provided on either the front or rear of the magnetic layer. The long-chain perfluoroalkyl carboxylate is used for the lubricating agent. The lubricity is thus maintained even in a low temp. region and the lubricating effect is maintained for a long period of time, by which the coefft. of friction is decreased and the running durability and friction resistance are improved.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a magnetic recording medium having a magnetic layer mainly composed of magnetic powder and a resin binder on a non-magnetic support. The present invention relates to a magnetic recording medium with improved properties.

[Summary of the invention]

The present invention provides long-term lubrication by holding a lubricant containing a long-chain carboxylic acid perfluoroalkyl ester in a magnetic recording medium having a magnetic layer mainly composed of magnetic powder and a resin binder on a non-magnetic support. The objective is to provide a magnetic recording medium that has long-lasting effects and excellent running stability and abrasion resistance.

(Prior Art) Magnetic tapes are required to have various characteristics such as having a particularly low coefficient of friction, smooth and stable running properties, a small amount of powder falling off, and good splicability. When magnetic tape is used in magnetic recording and reproducing devices such as video tape recorders (hereinafter abbreviated as VTR), it runs at high speed while physically contacting tape guides, magnetic heads, etc., so it has poor abrasion resistance. It is important to be able to run stably for long periods of time.For example, if the friction coefficient of the tape surface changes during recording or playback, the tape will vibrate at the guide or magnetic head.As a result, the tape There are disadvantages in that the recorded/playback signals (for example, timbre signals) change in frequency and become a sound different from the cause wave number, or the vibration sound of the tape (so-called Q sound) can be directly heard.

In order to prevent this, various attempts have been made to impart lubricity to the tape. For example, a solid lubricant such as molybdenum disulfide, graphite, or wax is added to a magnetic paint containing magnetic powder and a binder. However, this solid lubricant is not desirable because it is not very effective in terms of durability, and if added in large amounts, it deteriorates the magnetic properties.

On the other hand, higher fatty acids, higher fatty acid esters, paraffinic hydrocarbons, silicone oils (e.g. dimethyl silicone oil, diphenyl silicone oil), etc. may be used as lubricants, but even these may provide sufficient durability and lubricity. This is particularly insufficient for VTR cassettes.

[Problem that the invention seeks to solve]

Even if a protective film is formed by applying a lubricant as described above, it is not very effective in terms of durability, running performance, and friction resistance, and blooming, where the lubricant oozes onto the surface of the magnetic layer, tends to occur. There were various problems such as tape sticking phenomenon, stick-slip, etc.

Furthermore, the lubricating effect must be excellent under any usage conditions, but conventional lubricants have a limited usable temperature.For example, many of them solidify or freeze at low temperatures, making it difficult to achieve their lubricating effect. I couldn't let it go.

Therefore, an object of the present invention is to provide a magnetic recording medium that maintains lubricity under any usage conditions and has excellent running stability and friction resistance.

[Means for solving problems]

As a result of intensive research to achieve the above object, the present inventors discovered that carboxylic acid perfluoroalkyl ester, which is an ester of aliphatic carboxylic acid and perfluoroalcohol, exhibits a good lubricating effect. A magnetic recording medium comprising a magnetic layer mainly composed of magnetic powder and a resin binder on a non-magnetic support, the magnetic recording medium comprising a long-chain carboxylic acid perfluoroalkyl ester. It is characterized by holding a lubricant containing.

The long-chain carboxylic acid perfluoroalkyl ester used as a lubricant in the present invention has the general formula % ([) (However, in the above general formula, n≧4, m≦20+1,
i≧2. ) is a compound represented by Here, the number of n in the aliphatic hydrocarbon group (-C,,11,) 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.

On the other hand, perfluoroalkyl group (-(crux) +C
If the number of i in F3) is 2 or more, it shows an effect as a lubricant, but if it is 5 or more, the effect becomes noticeable.

Carboxylic acid perfluoroalkyl esters are easily synthesized, for example, by reacting a corresponding acid chloride with a fluorine-containing alcohol. The reaction formula is as follows.

Clll1. COCl÷C*Fzk, + (CHz)
JOH base C, lH, Coo (CHi) JCkhb, +... (1
) Formula The above acid chloride can be easily synthesized by chlorinating a commercially available aliphatic carboxylic acid with phosphorus pentachloride PCl5 or thionyl chloride SOCl□. In particular, for aliphatic carboxylic acids with a small number of carbon atoms, thionyl chloride 5
It can be synthesized by chlorination with OC1z. The reaction formula is as follows.

CI s C,111,C00II-C,11,COCl・・
・Formula (2) On the other hand, fluorine-containing alcohol CkFz□+(C1l□)
For jOH, perfluorocarboxylic acid obtained by the Simmons method etc. is dimethylformamide (DMF).
It can be easily synthesized by chlorination in the presence of the compound and then reduction with a reducing agent.

The reaction formula is as follows.

... Formula (3) The above carboxylic acid perfluoroalkyl ester may be used alone as a lubricant, but it may also be mixed with a conventionally known lubricant to expand the usable temperature range. good.

The lubricants used include fatty acids or their metal salts;
Fatty acid amide, fatty acid ester, aliphatic alcohol or its alcohol; toside, aliphatic amine, polyhydric alcohol, sorbitan ester, mannintan ester, sulfurized fatty acid, aliphatic mercapcoun, modified silicone oil,
Perfluoroalkyl ethylene oxide, perfluoropolyethers, higher alkyl sulfonic acid or its metal salt, perfluoroalkyl sulfonic acid or its ammonium salt or its metal salt, perfluoroalkyl carboxylic acid or its metal salt, perfluoroalkyl carboxylic acid ester etc. are exemplified. In particular, the general formula C-F
Perfluoroalkyl carboxylic acid esters represented by Z, ..., IC0OR (where n represents an integer of 6 to 10 and R represents a hydrocarbon group having 1 to 25 carbon atoms) also have good low temperature characteristics. Therefore, it is suitable for use in combination with the above carboxylic acid perfluoroalkyl ester. Of course,
Lubricants that can be used in combination are not limited to these,
Any conventionally known lubricant can be used.

When included in the magnetic layer, the amount of the lubricant used in the present invention is 0.2 parts by weight per 100 parts by weight of the magnetic powder in the magnetic layer.
~1 part 4 parts (PHP) is preferred. In addition, when it is included in the back coat layer on the back side of the non-magnetic support, 0.2 to 0.2 to 100 parts by weight of the binder in back coat J5
Preferably, the amount is 20 parts by weight (PHR). Furthermore, when forming a top coat layer or coating layer consisting of the above lubricant, the amount of the lubricant applied is 1 to 100.
It is preferable that the value is 0■/M.

Next, the structure of a magnetic recording medium to which the present invention is applied is illustrated in FIGS. 1 to 5.

FIG. 1 shows a magnetic layer (2) containing a lubricant formed on the surface of a non-magnetic support (1). The same applies to the following figures, but the layer containing the lubricant is shown as a cross-section with interspersed spots. Figure 2 shows magnetism 1! Figure 3 shows a state in which a coating N (4) made of a lubricant is formed on the back surface of the non-magnetic support (1). Indicates the condition. Figure 4 shows the back coat layer (
Fig. 5 shows a state in which a lubricant is contained in the back coat N (5), and further shows a state in which a coating layer (4) made of a lubricant is formed on the back coat N (5). The bank coat Jg (5) is provided for various purposes, including stabilizing running properties by appropriately controlling the surface roughness of the back surface, and preventing static electricity. For this purpose, the back coat layer may be coated with a binder mixed with carbon black, or may further contain a nonmagnetic pigment such as α-FezO, alumina, talc, etc. The magnetic recording medium of the present invention can be used not only for 611 tapes but also for magnetic disks having magnetic layers on the front or back surfaces. Also, the location where the lubricant is held is
It can be variously placed in the magnetic layer (2) or on the front and/or back surface of the magnetic layer (2). That is, in the present invention, a magnetic recording medium holding a long-chain carboxylic acid perfluoroalkyl ester includes cases in which this compound is internally added to the above-mentioned magnetic layer, top coat layer, and back coat layer, and further includes a magnetic surface, This also includes the case where this compound is attached to the surface of the back coat layer.

As mentioned above, a long-chain carboxylic acid perfluoroalkyl ester is included in the magnetic layer, or a top coat layer provided on the magnetic layer and/or a bath coat layer provided on the support opposite to the magnetic layer) is added to the FJ with the above length. When a chain carboxylic acid perfluoroalkyl ester is present, the lubricity of the top coat layer and back coat layer can be improved. As the solvent in this case, a low boiling point solvent such as freon, hexane, ethanol, etc. can be used.

As magnetic powder that can be used for the magnetic layer, γ-PezOi+
Fe3O4,r Fe,03 and Fe+04?
T Fez doped or coated with quartz, cobalt
O*, T Fe3O4 or FexOa, C
oxide magnetic powder such as row, Fe, Ni, Co.

Pe-Ni alloy, Fe-Co alloy, Fe-N1-P alloy, Fe-Ni-Co alloy, Fe-Co-8 alloy, Fe-
Co-V alloy.

re-Mn-'ln alloy, Fe-Ni-Zn alloy,
Fe-Ni -Co-Cr alloy + Fe Ni
CoP alloy, Fe-Co-Cr-8 alloy, Ni
-Co alloy, Co-P alloy, Mn-B1 alloy, Mn-A
metal magnetic powders mainly composed of Fe, Ni, and Co, such as l-alloys; hexagonal ferrite powders such as barium ferrite;
Examples include various ferromagnetic powders such as iron nitride, and in some cases two or more of these may be used in combination.

Especially when using metal magnetic powder, Si, AI, P
Elements such as % Mns Cr or compounds thereof may be added.

Binders that can be used in the magnetic layer include thermoplastic resins, thermosetting resins, reactive resins, electron beam curable resins, and mixtures thereof.

As a thermoplastic resin as a binder, the softening temperature is 15
Below 0°C, with an average molecular weight of 10,000 to 200,000, and a degree of polymerization of about 200 to 2,000, vinyl chloride
Vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, vinyl chloride-vinyl acetate-vinyl alcohol copolymer, vinyl chloride-vinyl acetate-maleic acid copolymer, acrylic ester- Acrylonitrile copolymer, acrylic ester-vinylidene chloride copolymer, acrylic ester-styrene copolymer, methacrylic ester-acrylonitrile copolymer, methacrylic ester-vinylidene chloride copolymer, methacrylic ester-styrene copolymer acrylonitrile-butadiene-acrylic acid copolymer, acrylonitrile-butadiene-methacrylic acid copolymer,
Polyvinyl butyral, polyvinyl acecool, urethane elastomer, polyvinyl fluoride, vinylidene chloride
Acrylonitrile copolymer, acrylonitrile-butadiene copolymer, polyamide resin, cellulose derivative (cellulose acetate butyrate, cellulose diacetate, cellulose triacetate, cellulose propionate, nitrocellulose, etc.), styrene-butadiene copolymer, polyester resin, Chlorovinyl ether
Acrylic ester copolymers, amino resins, various synthetic rubber-based thermoplastic resins, and mixtures thereof are used.

As the thermosetting resin or the reactive resin, those having a molecular weight of 20QOOO or less in the state of a coating solution, and which become insolubilized by a reaction such as condensation or addition after coating and drying are used.

Among these resins, those that do not soften or melt before the resin is thermally decomposed are preferred. Specifically, phenolic resins, phenoxy resins, epoxy resins, polyurethane curable resins, urea resins, melamine resins, alkyd resins, silicone resins, acrylic reaction resins, vinyl chloride-vinyl acetate resins, methacrylate copolymers, and Mixtures of diisocyanate prepolymers, mixtures of high molecular weight polyester resins and isocyanate prepolymers, urea-formaldehyde resins, mixtures of polyester polyols and isocyanates, polycarbonate-type polyurethanes, polyamide resins, low molecular wall glycols, high molecular weight diols, triphenylmectone triisomers 7 nate mixtures, polyamine resins, and mixtures thereof.

Examples of electron beam irradiation-curable resins include unsaturated prepolymers,
For example, maleic anhydride type, urethane acrylic type, polyester acrylic type, polyether acrylic type, polyurethane acrylic type, polyamide acrylic type, etc., or as a polyfunctional monomer, ether acrylic type, urethane acrylic type, phosphate ester acrylic type, etc. Examples include the oil type, hydrocarbon type, and the like. The above-mentioned binder resin may optionally contain -5OJ, -0SOJ, -COOM, -μ(
Hydrophilic polar groups such as OM'')2 (in the formula, M represents a hydrogen atom or an alkali metal, and Mo represents a hydrogen atom, an alkali metal, or a hydrocarbon group) are introduced to improve dispersibility in magnetic powder. May be improved.

The magnetic coating material forming the magnetic layer may contain additives such as a dispersant, an abrasive, a filler, an antistatic agent, and a rust preventive agent, if necessary.

For example, dispersants include lecithin, caprylic acid, caprylic acid, lauric acid, myristic acid, valmitic acid, stearic acid, oleic acid, elaidic acid, linoleic acid,
Fatty acids having 8 to 18 carbon atoms such as lyrinic acid and stearolic acid (R represented by R-COOII has 7 to 7 carbon atoms)
17 saturated or unsaturated alkyl groups), alkali metals (Li, Na, K, etc.) or alkaline earth metals (Mg, Ca, etc.) of the above fatty acids.

(Ba, etc.), fluorine-containing compounds of the aforementioned fatty acid esters, polyalkylene oxide alkyl phosphate esters, lecithin, trialkyl polyolefin oxy quaternary ammonium salts (alkyl has 1 carbon number)
-5, olefins include ethylene, propylene, etc.). In addition, higher alcohols having 12 or more carbon atoms, sulfuric esters, and the like can also be used. Further, a combination of a sulfonic acid salt of a succinic acid ester (including an ethylene glycol ester), a polycarboxylic acid of a maleic acid copolymer, an amine surfactant, or a polyoxine alkylene glycol can also be used. These dispersants may be used alone or in combination of two or more. These dispersants are added in an amount of 1 to 20 parts by weight per 100 parts by weight of the magnetic powder.

As the coupling agent, known titanate coupling agents, silane coupling agents, etc. may be used in combination.

Commonly used abrasive materials include fused alumina, silicon carbide, chromium oxide, corundum, artificial corundum, diamond, artificial diamond, garnet, emery (main components are corundum and magnetic iron I12), titanium dioxide, etc. used. These abrasives have a Mohs hardness of 5
The above is the average particle diameter of 0.05 to 5 μm, particularly preferably 0.1 to 2 μm. These abrasives are used in an amount of 1 part by weight per 100 parts by weight of magnetic powder.
It is added in a range of 20 parts by weight.

As fillers, goethite (α-Fe20i1), red iron (α-Fe20i), fine powder silica gel, colloidal silica, precipitated silica, calcium carbonate, barium carbonate, strontium carbonate, barium chloride, strontium chloride, magnesium hydroxide, Potassium titanate, zinc oxide, titanium oxide, kaolin, talc, diatomaceous earth, Cu
tOs 2ZnO・Sing・HzOlLa, Ce
-, Prs Md and Sm fluorides, glass powder, etc. are used. These fillers have a Mohs hardness of less than 5 and an average particle size of 0.05 to 5 μm, preferably 0.1
It is a non-tn fine powder of ~2 μm. These fillers are added in an amount of 1 to 20 parts by weight per 100 parts by weight of the magnetic powder.

Carbon blank and Gura are used as antistatic agents.

phyto, tin oxide-antimony oxide type compound.

Titanium oxide-tin oxide-antimony oxide type compound.

Conductive powder such as carbon black graft polymer, natural surfactant such as saponin, alkylene oxide type 5
Nonionic surfactants such as glycerin type and glycidol type, pyridine and other complex NWIs.

Cationic surfactants such as phosphonium or sulfoniums, anionic surfactants containing acidic groups such as carboxylic acids, sulfonic acids, phosphoric acids, sulfate ester groups, phosphate ester groups, amino acids, aminosulfonic acids, and sulfuric acid of amino alcohols. Alternatively, amphoteric activators such as phosphoric acid esters may be used. These conductive fine powders are added in an amount of 2 to 20 parts by weight per 100 parts by weight of the binder, and the surfactant is added in an amount of 0.1 to 10 parts by weight. These surfactants may be used alone or in combination. Although they can be used as antistatic agents, they may also be used for other purposes such as dispersion, improving magnetic properties, improving lubricity, and as coating aids.

Rust inhibitors include phosphoric acid, sulfamide, guanidine,
Pyridine, amine, urea, zinc chromate, calcium chromate, strontium chromate, etc. can be used, especially dicyclohexaneamine nitride, cyclohexylamine chromate, diisopropylamine nitrite, jetanolamine phosphate, cyclohexylammonium carbonate, hexamethylene diamine carbonate. , propylene diamine stearate 1
・Using a volatile rust inhibitor (inorganic or organic acid salt of amine, amide, or imide) such as guanidine carbonate, triethanolamine nitrite, and morpholine stearate improves the rust prevention effect. These anti-corrosion agents have a content of 0.0% per 100 parts by weight of magnetic fine powder. O is added in a range of 1 to 20 parts by weight.

The solvents added to the above paint or the diluting solvent for this paint are acetone, methyl ethyl ketone,
Methyl isobutyl ketone, cyclohexanone, etc.
methanol, ethanol.

Alcohols such as propatool, butanol, esters such as methyl acetate, ethyl acetate, butyl acetate, glycol acetate, ethyl lactate, ethylene glycol monoacetate, ether, monoethyl ether, glycol dimethyl ether, glycol monoethyl ether, dioxane, tetrahydrofuran Ethers such as benzene, toluene.

Aromatic hydrocarbons such as xylene, halogenated hydrocarbons such as methylene chloride, carbon tetrachloride, chloroform, dichlorobenzene, and nitropropane can be used.

The magnetic powder, the above-mentioned binder resin, dispersant, lubricant, abrasive, antistatic agent, solvent, etc. are kneaded to form a magnetic paint.

For mixing and purification, the magnetic powder and each of the above-mentioned components are fed into a kneading machine either simultaneously or sequentially. For example, there is a method in which magnetic powder is first added to a solution containing a dispersant and kneaded for a predetermined period of time, and then the remaining components are added and kneaded continuously to form a magnetic paint.

Various types of kneading machines are used for mixing the number of wires. For example, two-roll mill, Miki roll mill, ball mill,
These include pebble mills, sand grinders, high-speed impeller dispersers, high-speed stone mills, high-speed impact mills, disperser kneaders, high-speed mixers, homogenizers, ultrasonic dispersers, etc.

Materials for the non-magnetic support include polyesters such as polyethylene terephthalate and polyethylene-2,6-nuclate, polyolefins such as polyethylene and polypropylene, cellulose triacetate, cellulose diacetate, cellulose acenate butyrate, and cellulose acetate propionate. cellulose derivatives such as, vinyl resins such as polyvinyl chloride, polyvinylidene chloride,
Plastics such as polycarbonate, polyimide, polyamideimide, etc. and aluminum depending on the application.

Non-magnetic metals such as copper, tin, zinc or non-magnetic alloys containing these, ceramics such as glass, ON, Si carbide, porcelain and earthenware, paper, baryta, or carbon such as polyethylene, polypropylene, ethylene-butene copolymers, etc. Paper such as paper coated or laminated with α-polyolefins having 2 to 10 atoms can also be used.

Further, the shape of the nonmagnetic support may be any film, tape, sheet, disk, card, drum, etc., and various materials are selected as necessary depending on the shape.

The thickness of these non-Efg, sexual supports is usually about 2 to 100 mm.
The thickness is about μm, preferably 3 to 50 μm. In particular, when using a hard disk or magnetic card, 0.5
It is said to be about 101■. Moreover, in the case of a drum shape, it is cylindrical and its shape is determined depending on the recorder used.

Coating methods for forming a magnetic layer by coating the magnetic paint on the non-magnetic support include air doctor coating, blade coating, air knife coating, squeeze coating, impregnation coating, reverse roll coating, transfer roll coating, Clavier coat, kiss coat, cast coat, spray coat, spin cord, etc. can be used, but are not limited thereto.

[Effect]

A lubricant containing a long-chain carboxylic acid perfluoroalkyl ester can be retained in a magnetic recording medium formed by forming a magnetic layer mainly composed of magnetic powder and a resin binder on a non-magnetic support, so that the lubricant is good even at low temperatures. It exhibits a strong lubricating effect, reduces the coefficient of friction, and also eliminates running deterioration.

[Examples] Specific examples of the present invention will be described below, but the present invention is not limited to these examples.

First, a carboxylic acid perfluoroalkyl ester was synthesized according to the following synthesis example.

Synthesis Example 1 Oleic acid pencdecafluorooctyl ester (C+
J. C00C)IzCJ+s) This compound was prepared by preparing pentadecafluorooctanoyl chloride in anhydrous toluene by the method of Filler et al. [Journal of the American Society (Jouna)].
l of American 5ocie-ty) mutual 2
693 (1953)) and triethylamine were dissolved, and commercially available oleic acid was added thereto according to the method of T. R. Wood et al. (Journal of the American Society (1953)). Journal of＾meri
can 5ociety) 66287 (1944)
) by dropping oleic acid chloride obtained by chlorination with oxalyl chloride. After completion of the dropwise addition, the mixture was stirred overnight and washed with dilute hydrochloric acid, dilute alkaline water (8 liquids), and water in that order.The solvent, toluene, was removed and the mixture was purified by thin vacuum distillation.

Synthesis Example 2 Rirunic acid pentadecafluorooctyl ester (C+J
z*C00CIItCtP+s) In the same manner as in Synthesis Example 1, linoleic acid chloride obtained by chlorinating commercially available linoleic acid using oxalyl chloride was dropped into an anhydrous toluene solution containing pentadecafluorooctatotool and triethylamine. Thereafter, the same treatment as in Synthesis Example 1 was carried out for purification.

Synthesis Example 3 Linoleic acid pentadecafluorooctyl ester (C+
dli+C00C1l□CJ+s) In the same manner as in Synthesis Example 1, commercially available linoleic acid was chlorinated using oxalyl chloride, and linoleic acid chloride was dropped into an anhydrous toluene solution containing pentadecafluorooctatotool and triethylamine. Thereafter, the same treatment as in Synthesis Example 1 was carried out for purification.

Synthesis Example 4 Linoleic acid nonadecafluorodecyl ester (C+Jt
+C00CHzC1F+,) Commercially available linoleic acid was chlorinated using oxalyl chloride in the same manner as in Synthesis Example I. Linoleic acid chloride was converted to nonadecafluorooctanoic acid chloride using R Fillcr (R, Fillcr).
method (Journal of American Society (Jo
unalof American 5ociety)
The mixture was added dropwise to an anhydrous toluene solution containing triethylamine and nonadecafluorodecanol obtained by reduction according to No. 752,693 (1953)). Thereafter, the same treatment as in Synthesis Example 1 was carried out for purification.

Synthesis Example 5 Isostearic acid nonadecafluorodecyl ester (C
+dhsCOOC1hCqF+w) Isostearic acid chloride obtained by chlorinating commercially available isostearic acid with oxalyl chloride in the same manner as in Synthesis Example 1 was dropped into an anhydrous toluene solution containing nonadecafluorodecanol and triethylamine. Thereafter, the same treatment as in Synthesis Example 1 was carried out for purification.

Synthesis Example 6 Butanoic acid pentadecafluorooctyl ester (C41
1*C00CIhCJ ls) In the same manner as in Synthesis Example 1, commercially available butanoic acid was chlorinated using oxalyl chloride, and then butanoic acid chloride was dropped into an anhydrous toluene solution containing pentadecafluorooctatotool and triethylamine. Thereafter, the same treatment as in Synthesis Example 1 was carried out for purification.

Table 1 shows the boiling points and yields of Compounds 1 to 6 of Synthesis Examples 1 to 6 obtained as described above.

Example I Co'IIt-FezOi
100 parts by weight carbon (antistatic agent)
5 parts by weight Lecithin (dispersant) 1 part by weight Methyl ethyl ketone 150 ni1
150 parts by weight Methyl isobutyl ketone The above composition was used as a basic composition, and 1 part of oleic acid pentadecafluorooctyl ester of Compound 1 synthesized in Synthesis Example 1 was added to the basic composition, and mixed in a ball mill for 24 hours. Then, just before coating, 4 parts by weight of a curing agent was added and stirred for 30 minutes. This magnetic paint was applied onto a polyethylene terephthalate film having a thickness of 12 μm so that the thickness after drying would be 5 μm, and after performing magnetic field orientation, it was dried and wound up. This was calendered and then cut into 1/2 inch width to prepare sample tapes.

Example 2 1.5% of lylunic acid pentadecafluorooctyl ester of Compound 2 synthesized in Synthesis Example 2 was added to the basic composition of Example 1.
A sample tape was prepared in the same manner as in Example 1 using the magnetic paint added in parts by weight.

Example 3 Linoleic acid pentadecafluorooctyl ester of Compound 3 synthesized in Synthesis Example 3 was added to the basic composition of Example 1 in 1.
A sample tape was prepared in the same manner as in Example 1 using a magnetic paint containing 5 parts by weight.

Example 4 A sample was prepared in the same manner as in Example 1 using a magnetic paint in which 1.5 parts by weight of linoleic acid nonadecafluorodecyl ester of Compound 4 synthesized in Synthesis Example 4 was added to the basic composition of Example 1. I made a tape.

Example 5 One portion of isostearic acid nonadecafluorodecyl ester of Compound 5 synthesized in Synthesis Example 5 was added to the basic composition of Example 1.
．． A sample tape was prepared in the same manner as in Example 1 using a magnetic paint containing 5 parts by weight.

Example 6 1.5% butanoic acid pentadecafluorooctyl ester of Compound 6 synthesized in Synthesis Example 6 was added to the basic composition of Example 1.
A sample tape was prepared in the same manner as in Example 1 using the magnetic paint added in parts by weight.

Example 7 A sample tape was prepared in the same manner as in Example 1 using the basic composition of Example 1 as a magnetic paint. A 1.0% by weight n-hexane solution of oleic acid pentadecafluorooctyl ester of Compound 1 synthesized in Synthesis Example 1 was applied to the magnetic layer of the sample tape so that the coating amount of the ester was 16011.
A sample tape was prepared by applying (top coat) the sample to 1/II.

Example 8 A sample tape was prepared in the same manner as in Example 1 using the basic composition of Example 1 as a magnetic paint. A 1.0 wt% n-hexane solution of compound 2 (compound 2) synthesized in Synthesis Example 2, n-hexane, was applied to the magnetic layer of the sample tape so that the coating amount of the ester was 160 μ/m.
A sample tape was prepared by applying (top coat) so that the result was as follows.

Comparative Example A sample tape was prepared in the same manner as in Example 1 using a magnetic paint containing only the basic composition of Example 1 without adding any lubricant.

The friction coefficient and stick-slip of each of the prepared sample tapes were measured before and after aging (3 days at a temperature of 40° C. and a relative humidity (RH) of 80%). The results are shown in Table 2.

Table 2 (In this table, ○ indicates good quality and × indicates poor quality.) (See the margins below) As is clear from Table 2, the magnetic recording medium according to the present invention can suppress the coefficient of friction to an extremely small value. ,
Stick-slip can be avoided.

In particular, in magnetic recording media using the top coat method, it is possible to eliminate the running deterioration caused by changes in the magnetic field, which has been a problem in the past. In contrast, magnetic recording media without lubricant
It also had a large number of 112!1 coefficients, resulting in poor stain slip.

〔Effect of the invention〕

As is clear from the above description, in the present invention,
Since long-chain carboxylic acid perfluoroalkyl ester is used as a lubricant for magnetic recording media that have a magnetic layer mainly composed of magnetic powder and resin binder, lubricity is maintained even at low temperatures, and the lubrication effect is maintained over a long period of time. It is possible to obtain a magnetic recording medium that lasts long, has a small friction coefficient, and has excellent running stability and friction resistance.

[Brief explanation of drawings]

FIG. 1 is an enlarged sectional view of a main part showing a configuration example of a magnetic recording medium to which the present invention is applied, FIG. 2 is an enlarged sectional view of a main part showing another example of a structure of a magnetic recording medium, and FIG. The figure is an enlarged cross-sectional view of main parts showing still another example of the configuration of a magnetic recording medium.
FIG. 4 is an enlarged cross-sectional view of a main part showing still another example of the structure of a magnetic recording medium, and FIG. 5 is an enlarged cross-sectional view of a main part showing still another example of a structure of a magnetic recording medium. 1...Nonmagnetic support 2...Magnetic layer 3...Top coat layer 4...Coating layer 5...Back coat layer Patent applicant Sony Corporation representative Patent attorney Kodo Koike Materials Sakae Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] A magnetic recording medium having a magnetic layer mainly composed of magnetic powder and a resin binder on a non-magnetic support, characterized in that the magnetic recording medium retains a lubricant containing a long-chain carboxylic acid perfluoroalkyl ester. magnetic recording media.