JP2002367142A - Magnetic recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic recording medium wherein output deterioration due to the burning or the like between a head and a media is suppressed and satisfactory still characteristics and enhanced durability can be obtained. SOLUTION: The magnetic recording medium has a lubricant of heptyl stearate and the like in or/and on a magnetic layer, with <=50% high temperature oxidation stability by thermal analysis of magnetic powder which is a constituent component of the magnetic layer 3, containing 20-100 mg/m<2> lubricant that can be extracted by n-hexane.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium such as a magnetic tape.

[0002]

2. Description of the Related Art In magnetic recording media corresponding to video tapes, data tapes, and the like, studies on improving electromagnetic conversion characteristics have been actively made for the purpose of achieving higher recording density and higher image quality. In general, running properties and durability are important characteristics of a magnetic recording medium, and it is an important issue in designing a medium to secure running properties and durability while improving electromagnetic conversion characteristics.

In order to improve the electromagnetic conversion characteristics,
Improvements in magnetic properties, reduction in spacing loss by making the surface of the magnetic tape mirror-finished, and the like are being studied. For example, in a coating type magnetic recording medium, as a method of mirror-finishing the surface of a magnetic tape, the surface properties of a support may be smoothed, or the particle size of a ferromagnetic powder or an abrasive may be reduced. A device such as uniform dispersion is devised. Further, for the purpose of making the surface of the magnetic tape mirror-finished and for highly filling the ferromagnetic powder, a calender treatment is performed after a magnetic paint is applied and dried.

On the other hand, magnetic heads are also being developed, and the use of magnetic film materials having high saturation magnetic flux density and high magnetic permeability, that is, metal heads such as amorphous head alloys and superstructure artificial lattice films have been actively developed. Has begun to be used. As described above, with the improvement in the performance of the magnetic head, the current situation is that the metal head and the metal medium are increasingly shared.

[0005]

However, as is well known, in a system using a metal head and a metal medium, a head burn-in phenomenon occurs when the medium runs in a low humidity environment, and a sudden burn-in phenomenon occurs. Output degradation occurs. This seizure phenomenon is greatly related to head abrasion, and it has been confirmed that a certain amount of head abrasion can be improved by providing the tape with a certain amount of head abrasion. However, this countermeasure has a problem of deteriorating the still characteristics.

It has also been confirmed that the improvement of the still characteristics can be improved by increasing the particle size of the abrasive added to the magnetic layer. However, in such a case, there is a problem that the tape surface is polished by the seizure adhered in a low humidity environment, and the output is greatly reduced.

In order to solve these problems, Japanese Patent Laid-Open Publication No. Hei 6-282837 discloses that the average abrasive particles having a Mohs hardness of 6 or more contained in the magnetic layer are inclined from the outermost surface to the inside. With this configuration, a method for improving output degradation and still durability has been disclosed.

However, in order to further improve the electromagnetic conversion characteristics, the method disclosed in Japanese Patent Application Laid-Open No. 6-282837 is inadequate. In order to improve both output degradation and still characteristics, it is difficult to design.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and it is possible to suppress output deterioration due to burn-in between a head and a medium, and to improve a good still characteristic and durability. It is an object of the present invention to provide an obtained magnetic recording medium.

[0010]

That is, according to the present invention, a lubricant is contained in and / or on the magnetic layer, and the high-temperature oxidation stability of the magnetic powder as a component of the magnetic layer by thermal analysis is 50%.
The present invention relates to a magnetic recording medium, wherein the amount of the lubricant extracted with n-hexane is 20 to 100 mg / m ² .

Here, the above-mentioned “high-temperature oxidation stability rate” means a value obtained by using the following equation (1).

[0012]

(Equation 1) [However, in the above formula (1), Tg is a change in weight of the magnetic powder when the magnetic powder is heated and oxidized,
That is, it represents an oxidation reaction rate. Tg ¹ is the Tg when the temperature of the magnetic powder is raised to 200 ° C. at 100 ° C./min in an N ₂ atmosphere and then held for 30 minutes in an N ₂ (80%) + O ₂ (20%) atmosphere. Tg ² represents Tg when the magnetic powder is completely oxidized, that is, when it is saturated. ]

According to the present invention, since the high-temperature oxidative stability of the magnetic powder by thermal analysis is 50% or less, even when the head and the medium slide, even in an environment in which high-temperature frictional heat is generated, seizure may occur. Is suppressed, and output degradation can be suppressed.

In addition, since the lubricant is retained in and / or on the magnetic layer and the amount of the lubricant extracted by n-hexane is specified as ²⁰ to 100 mg / m ² , excellent still Has properties and durability.

Therefore, the magnetic recording medium of the present invention can achieve both suppression of output deterioration due to burn-in between the head and the medium and improvement in still characteristics and durability.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail based on embodiments.

In general, a coating type magnetic recording medium is composed of a composite material such as a binder of an inorganic pigment or a high molecular compound. For example, the mixing ratio of the inorganic pigment to the binder exceeds a certain value. In such a case, voids and voids are generated in the medium, and the voids and voids tend to increase as the blending ratio of the inorganic pigment increases. And
When the amount of the lubricant present on the surface of the magnetic recording medium is reduced by sliding, the lubricant existing inside the magnetic layer passes through the above-described voids and holes, and slides. It is believed that it is supplied on the surface and effectively affects the still characteristics. Therefore, of the added lubricant, the amount of the lubricant confined inside the magnetic layer cannot be expected as long as it does not permeate onto the surface of the magnetic recording medium. The amount of the lubricant present in the region is related to the still characteristics of the magnetic recording medium.

For this reason, when the surface of the magnetic recording medium is mirror-finished by calendering or the like, even if the amount of the lubricant added is the same, the lubricant may be used in the still recording medium of the magnetic recording medium depending on the calendering conditions. The effects on the properties are very different. Therefore, it is difficult to control the still characteristics and durability of the magnetic recording medium simply by adding the lubricant to the magnetic paint alone. On the other hand, after calendering, there is also a method of adding the lubricant by a method such as a top coat on the magnetic layer.In this case, too, if the amount of the lubricant is too large, the magnetic tape is increased due to an increase in friction. Therefore, it is necessary to find an effective amount of the magnetic recording medium because the magnetic recording medium tends to stick to the recording medium, and the running reliability may decrease.

The inventors of the present invention have conducted intensive studies to solve the above problems, and as a result, the amount of the lubricant extracted with n-hexane was substantially equal to the amount of the lubricant existing on the surface of the magnetic recording medium. And found the most effective range for the amount of the lubricant and arrived at the present invention. Here, the “amount of the lubricant present substantially on the surface of the medium” is, more specifically, 0.1% from the surface of the magnetic recording medium.
It means the amount of the lubricant existing in the range of 2 to 0.5 μm, or the amount of the lubricant existing in the surface area of the magnetic layer.

The magnetic recording medium according to the present invention is characterized in that the amount of the lubricant extracted with n-hexane is 20 to 100 m
Since it is specified as g / m ² , more preferably 40 to 80 mg / m ² , it has more excellent still characteristics and durability. If the amount of the lubricant extracted with n-hexane is less than 20 mg / m ² , the improvement of the still characteristics and the like may not be achieved. Conversely, if it exceeds 100 mg / m ² , the friction of the magnetic recording medium may increase due to an increase in friction. Sticking and the like are likely to occur, and the running reliability decreases.

The method using n-hexane for extracting the lubricant has the best relation with the still property,
This is the most effective method because it is inexpensive, simple, and has good reproducibility. There is another extraction method, for example, a method in which a component that has been vaporized by heating a magnetic recording medium is analyzed by gas chromatography or the like, but no relationship with still characteristics or the like was found.

As the lubricant, higher fatty acid esters are preferred. As the higher fatty acid ester, an ester compound composed of a higher fatty acid having 16 or more and 22 or less carbon atoms and neopentyl alcohol is most preferable. In addition, a monobasic fatty acid having 10 or more and 24 or less carbon atoms ( However, it may be branched or contain an unsaturated bond.) And a monohydric alcohol having 1 to 18 carbon atoms (however, it may be branched or contain an unsaturated bond. Or an ester compound comprising an alkylene oxide monoalkyl ether. By using these, even when the same amount as the other higher fatty acid esters is present, it is possible to suppress the friction of the portion that slides at a low speed lower, and to form an oil film with more excellent durability. For this reason, it is possible to further improve running performance and durability.

Specific examples of the ester compound include methyl stearate, ethyl stearate, propyl stearate, butyl stearate, sec-butyl stearate, tert-butyl stearate, isobutyl stearate, and stearic acid. Pentyl acid,
Examples include heptyl stearate, octyl stearate, butoxyethyl stearate, butyl palmitate, pentyl palmitate, heptyl palmitate, octyl palmitate, isooctyl palmitate, octyl myristate, oleyl oleate, and the like.

The lubricant may be used in combination with a conventionally known lubricant in addition to the higher fatty acid esters. As the conventionally known lubricant, for example, higher fatty acids such as myristic acid and stearic acid,
Ester compounds of salts of these metals and amines, fatty acids with monohydric or higher alcohols up to hexavalent,
Examples include silicone oils and alkyl phosphates including those modified with fatty acids and the like.These may include other substituents such as ether bonds by the addition of ethylene oxide or the like, and may partially include a fluorine atom. May be included. Further, perfluoropolyether and its modified products are exemplified.

Generally, burn-in which causes output deterioration is an oxide. By suppressing the generation of this oxide, output deterioration can be suppressed, and high-temperature frictional heat is generated when the head and the medium slide, so that the oxidization stability at that high temperature is required for the magnetic powder. Since the magnetic recording medium according to the present invention has a high-temperature oxidation stability of 50% or less by thermal analysis of the magnetic powder constituting the magnetic layer, high-temperature frictional heat is generated, for example, when the head and the medium slide. Even under a reduced environment, generation of oxides as burn-in products is suppressed, and output deterioration can be suppressed.

As described above, the high-temperature oxidation stability of the magnetic powder by thermal analysis was specified to be 50% or less, but the lower limit is preferably set to 0%. With the above range,
Even in an environment in which high-temperature frictional heat is generated when the head and the medium slide, generation of oxides as burn-in products is further suppressed, and more excellent output deterioration suppressing effect can be obtained. However, if it exceeds 50%, generation of oxides cannot be suppressed, and output deterioration cannot be reduced.

The high-temperature oxidation stability can be obtained by using the above-mentioned equation (1). As a method of oxidizing the magnetic powder for measuring the high-temperature oxidation stability, for example, And TG-DTA (EXSTAR6000 series, manufactured by Seiko Instruments Inc.), the temperature was raised to 200 ° C. at 100 ° C./min in an N ₂ atmosphere, and then in an N ₂ (80%) + O ₂ (20%) atmosphere. The change in TG when held for 30 minutes at is measured.
Further, the value obtained when the TG is sufficiently oxidized and the TG is saturated is defined as the TG after the complete oxidation reaction, and a value obtained by dividing the TG from 100 ° C. to 200 ° C. by the value is defined as the high-temperature oxidation stability rate.

The ferromagnetic powder used in the present invention includes:
It is preferably a fine metal powder, for example, γ-FeO having a high-temperature oxidation stability of 50% or less by thermal analysis
x (x = 1.33 to 1.5), Co-modified γ-FeOx
(X = 1.33 to 1.5), a known ferromagnetic material such as a ferromagnetic alloy containing Fe, Ni or Co as a main component (75% or more), barium ferrite, or strontium ferrite can be used. In addition, these ferromagnetic powders include Al, Si, S, Sc, Ti, V, Cr, C
u, Y, Mo, Rh, Pd, Ag, Sn, Sb, Te,
Ba, Ni, Ta, W, Re, Au, Hg, Pb, B
It may contain atoms such as i, La, Ce, P, Mn, Zn, Co, Sr, and B.

The control of the high-temperature oxidation stability can be realized by changing the composition of the magnetic powder. In addition, a combination with the size such as the major axis length of the magnetic powder is effective. Yes, the longer the major axis length and the specific surface area, the better, but they may be appropriately selected depending on the format used.

As the binder that can be used in the magnetic recording medium according to the present invention, any resin material used in a usual coating type magnetic recording medium can be used.
The type is not particularly limited. Examples of typical binder resins include vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-vinyl alcohol copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, and chloride chloride. Vinyl-vinyl acetate-maleic acid copolymer, acrylate-vinylidene chloride copolymer, acrylate-acrylonitrile copolymer, methacrylic acid-vinylidene chloride copolymer, methacrylate-styrene copolymer, thermoplastic Polyurethane resin, phenoxy resin, polyvinyl fluoride, vinylidene chloride-acrylonitrile copolymer, butadiene-acrylonitrile copolymer, acrylonitrile-butadiene-methacrylic acid copolymer, polyvinyl butyral, cellulose derivative, styrene-butadiene copolymer, poly Ester resins, phenol resins, epoxy resins, thermosetting polyurethane resins, urea resins, melamine resins, alkyd resins, urea - formaldehyde resins, polyvinyl acetal resin, or mixtures thereof, and the like. Above all, polyurethane resin which is supposed to give flexibility,
Desirable are a polyester resin, an acrylonitrile-butadiene copolymer and the like, and a cellulose derivative, a phenol resin and an epoxy resin, which are said to impart rigidity. The binder may be one having improved durability by crosslinking an isocyanate compound, or one having an appropriate polar group introduced.

The magnetic layer may contain an inorganic pigment, which may be selected from alumina, chromium oxide, silicon oxide, titanium oxide, silicon carbide, calcium carbonate, α-
Examples include iron oxide, kaolin, graphite, mica, and titanium carbide.

It is also possible to add a curable resin into the magnetic layer in order to improve the durability. Specific examples include a thermosetting resin represented by a polyisocyanate compound and a polyepoxy compound, and an electron beam reactive curable resin. These can be used alone or in combination of two or more.

Further, a dispersant such as lecithin, an antistatic agent such as carbon black, an abrasive, and a rust inhibitor may be added to the magnetic layer as required. As the dispersant, antistatic agent, abrasive and rust preventive, any conventionally known materials can be used, and there is no particular limitation. The carbon black includes acetylene black, furnace black, and the like, depending on the manufacturing method.

Examples of the slurry abrasives usable in the present invention include α-alumina, β-alumina, fused alumina, silicon carbide, chromium oxide, cerium oxide, α-iron oxide, corundum, diamond, quartzite, Garnet, silicon nitride, boron nitride, molybdenum carbide, boron carbide, tungsten carbide, titanium oxide, etc. as the main component,
Known materials having a Mohs hardness of 6 or more are used alone or in combination. The average particle size of these abrasives is 0.01 to 2
Although μm is preferable, abrasives having different particle sizes may be combined as needed, or a single abrasive may be used by broadening the particle size distribution.

As the rust preventive, any rust preventive conventionally used in this type of magnetic recording medium can be used, and examples thereof include organic amines, phenols, naphthols, quinones, and the like. Examples include nitrogen-containing heterocyclic compounds such as riboflavin, oxygen-containing heterocyclic compounds such as guanosine, sulfur-containing heterocyclic compounds such as sulfolane, compounds containing a mercapto group such as thiophenol, and thiazole compounds.

As the material of the nonmagnetic support usable in the present invention, those generally used for magnetic recording media can be used, for example, polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyethylene, polypropylene and the like. Polyolefins, cellulose derivatives such as cellulose triacetate, cellulose diacetate, cellulose acetate butyrate, vinyl resins such as polyvinyl chloride and polyvinylidene chloride, polycarbonate, polyimide, polyamide imide, other plastics, metals such as aluminum and copper , Aluminum alloys, light alloys such as titanium alloys, ceramics, single crystal silicon, and the like.

The magnetic recording medium according to the present invention is obtained by dispersing the above-mentioned constituents of the magnetic powder and the magnetic layer having a high-temperature oxidation stability of 50% or less by thermal analysis in the binder, and The liquid is dispersed in an organic solvent selected from ethers, esters, ketones, aromatic hydrocarbons, aliphatic hydrocarbons, organic chlorinated compounds, and the like depending on the type of the binder and the like, for the magnetic layer. It can be produced by obtaining a paint and applying the paint for the magnetic layer on the non-magnetic support. Here, the lubricant may be added at any of the initial, middle, and end of the mixing and dispersion of the magnetic paint, and may be top-coated after the magnetic layer is formed.

In preparing the magnetic paint, a roll mill, a ball mill, a sand mill, a kneader, an extruder, a homogenizer, an ultrasonic disperser, or the like is used.
What is necessary is just to disperse and knead the compounding components.

On the side of the non-magnetic support on which the magnetic layer is not provided (the back side), a back coat layer is provided for the purpose of improving the runnability of the magnetic recording medium, and preventing charge and transfer. Can be provided. The thickness of the back coat layer is preferably 0.3 to 1.0 μm,
The back coat layer is formed by, for example, dispersing solid particles such as an inorganic pigment in a binder (which may be basically the same binder as that which can be used for the magnetic layer), and the type of the binder. Is prepared by kneading together with an organic solvent selected according to the above, and applying this to the back surface of the non-magnetic support.

Examples of the curing agent include aromatic polyisocyanates and aliphatic polyisocyanates, and adducts of these with active hydrogen compounds are preferred. As the aromatic polyisocyanate, toluene diisocyanate (TD
I), 1,3-xylene diisocyanate, 1,4-xylene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), p-phenyl diisocyanate, m-fail diisocyanate, 1,5-naphthyl diisocyanate, and the like. . Also,
Examples of the aliphatic polyisocyanate include hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate, cyclohexane diisocyanate, and isophorone diisocyanate (IPDI). Active hydrogen compounds forming adducts with these include ethylene glycol, 1,4-butanediol, 1,3-butanediol, neopentyl glycol, diethylene glycol, trimethylolpropane,
Glycerin and the like, and the average molecular weight is 100-5000.
Are preferred.

FIG. 1 is a schematic sectional view of a magnetic recording medium according to the present invention.

The magnetic recording medium 1 according to the present invention has a magnetic layer 3 formed on a non-magnetic support 2 by coating.
On the side of the non-magnetic support 2 on which the magnetic layer 3 is not provided, a back coat layer 4 is provided as necessary.
As described above, the high-temperature oxidation stability of the magnetic powder, which is a component of the magnetic layer 3, by thermal analysis is 50% or less. Also,
The lubricant is contained in the magnetic layer 3 (internal addition)
Alternatively, after the magnetic layer 3 is formed, it is top-coated (externally added), or internally and externally added, and n-
When the amount of the lubricant extracted by hexane is 20 to 10
0 mg / m ² .

Since the high-temperature oxidation stability of the magnetic powder by thermal analysis is 50% or less, the generation of seizure oxides, for example, in an environment in which high-temperature frictional heat is generated when a head and a medium slide. And output deterioration can be further suppressed.

Further, the above-mentioned extraction with n-hexane
The amount of lubricant is 20-100mg / m ^TwoIs identified as
Therefore, it has better still characteristics and durability.

Accordingly, the magnetic recording medium 1 according to the present invention
Can achieve both suppression of output deterioration due to burn-in between the head and the medium and improvement in still characteristics and durability.

In the magnetic recording medium according to the present invention, the magnetic layer is not limited to a single magnetic layer, but may be a laminate of a plurality of magnetic layers. Thus, a configuration in which an adhesive layer is formed may be adopted.

The material of the head suitably used for the magnetic recording medium according to the present invention includes a ferrite head, an SMX (sofmax) head, a laminated amorphous head, and the like, and is not particularly limited.

[0048]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described, but the present invention is not limited to these embodiments.

Example 1 First, a magnetic coating material having the composition shown in Table 1 below was dispersed by a sand mill, and then a curing agent (manufactured by Nippon Polyurethane Co., Ltd.)
Brand name: Coronate L) was added in an amount of 3 parts by weight and a lubricant (heptyl stearate) in an amount of 2 parts by weight.
It was applied on a 0 μm PET (polyethylene terephthalate) film so that the thickness after drying was 2.0 μm.

[0050]

[Table 1]

Thereafter, a magnetic field orientation treatment was performed, and the film was dried and wound up.

Next, a processing temperature of 115 ° C. and a line pressure of 300
Calendar treatment at kg / cm, temperature 60 ° C, 20
A hardening treatment was performed for a long time to form a magnetic layer. (Hereinafter, the calendar conditions are strong: temperature: 120 ° C., linear pressure: 350 kg
/ Cm, medium: temperature 115 ° C, linear pressure 300 kg / cm,
Weak: temperature 110 ° C., linear pressure 250 kg / cm, referred to as strong, medium and weak, respectively. )

On the side of the non-magnetic support on which the magnetic layer was not provided, a back coat layer having a composition shown in Table 2 below was formed to a thickness of 1.0 μm.

[0054]

[Table 2]

The wide tape obtained in this way is 8 m long.
The sample tape of Example 1 was fabricated by assembling in a video cassette.

[0056] Comparative Example 1 lubricant 1 part by weight of (heptyl stearate), except that calendering conditions were strong, to prepare a sample tape of Comparative Example 1 in the same manner as in Example 1.

[0057] Comparative Example 2 Lubricants 1 part by weight of (stearic acid heptyl), except calender conditions that a medium to prepare a sample tape of Comparative Example 2 in the same manner as in Example 1.

[0058] Comparative Example 3 Lubricants 1 part by weight of (heptyl stearate), except calender conditions were weak, to prepare a sample tape of Comparative Example 3 in the same manner as in Example 1.

[0059] Comparative Example 4 lubricant (heptyl stearate) 2 parts by weight, except that calendering conditions were strong, to prepare a sample tape of Comparative Example 4 in the same manner as in Example 1.

[0060] EXAMPLE 2 Lubricants 2 parts by weight (heptyl stearate), except calender conditions were weak, to prepare a sample tape of Example 2 in the same manner as in Example 1.

[0061] 3 parts by weight Example 3 Lubricants (heptyl stearate), except that calendering conditions were strong, to prepare a sample tape of Example 3 in the same manner as in Example 1.

[0062] Example 4 lubricants 3 parts by weight (heptyl stearate), except calender conditions that a medium to prepare a sample tape of Example 4 in the same manner as in Example 1.

[0063] Example 5 lubricant 3 parts by weight (heptyl stearate), except calender conditions were weak, to prepare a sample tape of Example 5 in the same manner as in Example 1.

[0064] 4 parts by weight of Example 6 lubricant (heptyl stearate), except that calendering conditions were strong, to prepare a sample tape of Example 6 in the same manner as in Example 1.

[0065] Example 7 lubricant 4 parts by weight (heptyl stearate), except calender conditions that a medium to prepare a sample tape of Example 7 in the same manner as in Example 1.

[0066] Example 8 lubricant 4 parts by weight (heptyl stearate), except calender conditions were weak, to prepare a sample tape of Example 8 in the same manner as in Example 1.

[0067] Example 9 lubricant (heptyl stearate) 5 parts by weight, except that calendering conditions were strong, to prepare a sample tape of Example 9 in the same manner as in Example 1.

[0068] Comparative Example 5 lubricant 5 parts by weight (stearic acid heptyl), except calender conditions that a medium to prepare a sample tape of Comparative Example 5 in the same manner as in Example 1.

[0069] Comparative Example 6 lubricant 5 parts by weight (heptyl stearate), except calender conditions were weak, to prepare a sample tape of Comparative Example 6 in the same manner as in Example 1.

Example 10 A magnetic coating material having the composition shown in Table 3 below was dispersed by a sand mill, and then 3 parts by weight of a curing agent (manufactured by Nippon Polyurethane Co., product surface: Coronate L) and a lubricant (heptyl stearate) were used. Was added in an amount of 2 parts by weight.
Was applied so that the thickness after drying was 2.0 μm. The calendering conditions were as follows: processing temperature 115 ° C., line pressure 35
A sample tape of Example 10 was produced in the same manner as in Example 1 except that the pressure was set to 0 kg / cm.

[0071]

[Table 3]

[0072] Example 11 lubricant 2 parts by weight (heptyl stearate), except that calendering conditions that a medium to prepare a sample tape of Example 11 in the same manner as in Example 10.

[0073] 1 part by weight Comparative Example 7 lubricant (heptyl stearate), except that calendering conditions were strong, to prepare a sample tape of Comparative Example 7 in the same manner as in Example 10.

[0074] Comparative Example 8 lubricant 1 part by weight of (heptyl stearate), except that calendering conditions that a medium to prepare a sample tape of Comparative Example 8 in the same manner as in Example 10.

[0075] Comparative Example 9 lubricant 1 part by weight of (heptyl stearate), except that calendering conditions were weak, to prepare a sample tape of Comparative Example 9 in the same manner as in Example 10.

[0076] two parts Comparative Example 10 lubricant (heptyl stearate), except that the calendering conditions were strong, to produce a sample tape of Comparative Example 10 as in Example 10.

[0077] Example 12 lubricant 2 parts by weight (heptyl stearate), except that calendering conditions were weak, to prepare a sample tape of Example 12 in the same manner as in Example 10.

[0078] Example 13 lubricant 3 parts by weight (heptyl stearate), except that the calendering conditions were strong, to prepare a sample tape of Example 13 in the same manner as in Example 10.

[0079] Example 14 lubricant 3 parts by weight (heptyl stearate), except that calendering conditions that a medium to prepare a sample tape of Example 14 in the same manner as in Example 10.

[0080] Example 15 3 parts by weight of a lubricant (heptyl stearate), except that calendering conditions were weak, to prepare a sample tape of Example 15 in the same manner as in Example 10.

[0081] Example 16 lubricant 4 parts by weight (heptyl stearate), except that the calendering conditions were strong, to prepare a sample tape of Example 16 in the same manner as in Example 10.

[0082] Example 17 lubricant 4 parts by weight (heptyl stearate), except that calendering conditions that a medium to prepare a sample tape of Example 17 in the same manner as in Example 10.

[0083] Example 18 lubricant 4 parts by weight (heptyl stearate), except that calendering conditions were weak, to prepare a sample tape of Example 18 in the same manner as in Example 10.

[0084] Example 19 lubricant 5 parts by weight (heptyl stearate), except that the calendering conditions were strong, to prepare a sample tape of Example 19 in the same manner as in Example 10.

Example 20 A lubricant (heptyl stearate) was 5 parts by weight, and the calendering conditions were a processing temperature of 115 ° C. and a linear pressure of 300 kg / cm.
Example 20 was performed in the same manner as Example 10 except that
Was prepared.

[0086] Comparative Example 11 lubricant 5 parts by weight (heptyl stearate), except that calendering conditions that a medium to prepare a sample tape of Comparative Example 11 in the same manner as in Example 10.

[0087] Comparative Example 12 lubricant 5 parts by weight (heptyl stearate), except that calendering conditions were weak, to prepare a sample tape of Comparative Example 12 in the same manner as in Example 10.

Comparative Example 13 A magnetic coating material having the composition shown in Table 4 below was dispersed by a sand mill, and then 3 parts by weight of a curing agent (trade name: Coronate L, manufactured by Nippon Polyurethane Co.) and a lubricant (heptyl stearate) were used. 1 part by weight, and the thickness is 10.0 μm
Was applied so that the thickness after drying was 2.0 μm. In addition, a sample tape of Comparative Example 13 was produced in the same manner as in Example 1 except that the calendering conditions were set to be strong.

[0089]

[Table 4]

[0090] Comparative Example 14 lubricant 1 part by weight of (heptyl stearate), except that calendering conditions that a medium to prepare a sample tape of Comparative Example 14 in the same manner as in Comparative Example 13.

[0091] Comparative Example 15 lubricant 1 part by weight of (heptyl stearate), except that calendering conditions were weak, to prepare a sample tape of Comparative Example 15 in the same manner as in Comparative Example 13.

[0092] Comparative Example 16 lubricant (heptyl stearate) 2 parts by weight, except that the calendering conditions were strong, to prepare a sample tape of Comparative Example 16 in the same manner as in Comparative Example 13.

Example 21 2 parts by weight of a lubricant (heptyl stearate) were used under calendering conditions of a processing temperature of 120 ° C. and a linear pressure of 350 kg / cm.
Example 21 was performed in the same manner as in Comparative Example 13 except that
Was prepared.

[0094] Example 22 lubricant 2 parts by weight (heptyl stearate), except that calendering conditions that a medium to prepare a sample tape of Example 22 in the same manner as in Comparative Example 13.

[0095] Example 23 lubricant 2 parts by weight (heptyl stearate), except that calendering conditions were weak, to prepare a sample tape of Example 23 in the same manner as in Comparative Example 13.

[0096] Example 24 lubricant 3 parts by weight (heptyl stearate), except that the calendering conditions were strong, to prepare a sample tape of Example 24 in the same manner as in Comparative Example 13.

[0097] Example 25 lubricant 3 parts by weight (heptyl stearate), except that calendering conditions that a medium to prepare a sample tape of Example 25 in the same manner as in Comparative Example 13.

[0098] Example 26 lubricant 3 parts by weight (heptyl stearate), except that calendering conditions were weak, to prepare a sample tape of Example 26 in the same manner as in Comparative Example 13.

[0099] 4 parts by weight Example 27 lubricant (heptyl stearate), except that the calendering conditions were strong, to prepare a sample tape of Example 27 in the same manner as in Comparative Example 13.

[0100] Example 28 lubricant 4 parts by weight (heptyl stearate), except that calendering conditions that a medium to prepare a sample tape of Example 28 in the same manner as in Comparative Example 13.

[0102] Example 29 lubricant 4 parts by weight (heptyl stearate), except that calendering conditions were weak, to prepare a sample tape of Example 29 in the same manner as in Comparative Example 13.

[0102] Example 30 lubricant 5 parts by weight (heptyl stearate), except that the calendering conditions were strong, to prepare a sample tape of Example 30 in the same manner as in Comparative Example 13.

Example 31 5 parts by weight of a lubricant (heptyl stearate) were used under the calendering conditions of a processing temperature of 115 ° C. and a linear pressure of 300 kg / cm.
Example 31 was carried out in the same manner as in Comparative Example 13 except that
Was prepared.

[0104] Comparative Example 17 lubricant 5 parts by weight (heptyl stearate), except that calendering conditions that a medium to prepare a sample tape of Comparative Example 17 in the same manner as in Comparative Example 13.

[0105] Comparative Example 18 lubricant 5 parts by weight (heptyl stearate), calendar conditions except that the weak, to prepare a sample tape of Comparative Example 18 in the same manner as in Comparative Example 13.

Comparative Example 19 A magnetic coating material having the composition shown in Table 5 below was dispersed by a sand mill, and then 3 parts by weight of a curing agent (trade name: Coronate L, manufactured by Nippon Polyurethane Co.) and a lubricant (heptyl stearate) were used. 1 part by weight, and the thickness is 10.0 μm
Was applied so that the thickness after drying was 2.0 μm. In addition, a sample tape of Comparative Example 19 was produced in the same manner as in Example 1 except that the calendering conditions were set to be strong.

[0107]

[Table 5]

[0108] Comparative Example 20 lubricant 1 part by weight of (heptyl stearate), except that calendering conditions that a medium to prepare a sample tape of Comparative Example 20 in the same manner as in Comparative Example 19.

[0109] Comparative Example 21 lubricant 1 part by weight of (stearic acid heptyl), calendar conditions except that the weak, to prepare a sample tape of Comparative Example 21 in the same manner as in Comparative Example 19.

[0110] Comparative Example 22 lubricant (heptyl stearate) 2 parts by weight, except that the calendering conditions were strong, to prepare a sample tape of Comparative Example 22 in the same manner as in Comparative Example 19.

[0111] Comparative Example 23 lubricant 2 parts by weight (heptyl stearate), except that calendering conditions that a medium to prepare a sample tape of Comparative Example 23 in the same manner as in Comparative Example 19.

[0112] Comparative Example 24 lubricant 2 parts by weight (heptyl stearate), except that calendering conditions were weak, to prepare a sample tape of Comparative Example 24 in the same manner as in Comparative Example 19.

[0113] 3 parts by weight Comparative Example 25 lubricant (heptyl stearate), except that the calendering conditions were strong, to prepare a sample tape of Comparative Example 25 in the same manner as in Comparative Example 19.

[0114] Comparative Example 26 lubricant 3 parts by weight (heptyl stearate), except that calendering conditions that a medium to prepare a sample tape of Comparative Example 26 in the same manner as in Comparative Example 19.

[0115] Comparative Example 27 lubricant 3 parts by weight (heptyl stearate), calendar conditions except that the weak, to prepare a sample tape of Comparative Example 27 in the same manner as in Comparative Example 19.

[0116] 4 parts by weight Comparative Example 28. lubricant (heptyl stearate), except that the calendering conditions were strong, to prepare a sample tape of Comparative Example 28 in the same manner as in Comparative Example 19.

[0117] Comparative Example 29 lubricant 4 parts by weight (heptyl stearate), except that calendering conditions that a medium to prepare a sample tape of Comparative Example 29 in the same manner as in Comparative Example 19.

[0118] Comparative Example 30 lubricant 4 parts by weight (heptyl stearate), except that calendering conditions were weak, to prepare a sample tape of Comparative Example 30 in the same manner as in Comparative Example 19.

[0119] Comparative Example 31 lubricant (heptyl stearate) 5 parts by weight, except that the calendering conditions were strong, to prepare a sample tape of Comparative Example 31 in the same manner as in Comparative Example 19.

[0120] Comparative Example 32 lubricant 5 parts by weight (heptyl stearate), except that calendering conditions that a medium to prepare a sample tape of Comparative Example 32 in the same manner as in Comparative Example 19.

[0121] Comparative Example 33 lubricant 5 parts by weight (stearic acid heptyl), calendar conditions except that the weak, to prepare a sample tape of Comparative Example 33 in the same manner as in Comparative Example 19.

Comparative Example 34 A magnetic coating material having the composition shown in Table 6 below was dispersed by a sand mill, and then 3 parts by weight of a curing agent (trade name: Coronate L, manufactured by Nippon Polyurethane Co., Ltd.) and a lubricant (heptyl stearate) were used. 1 part by weight, and the thickness is 10.0 μm
Was applied so that the thickness after drying was 2.0 μm. Further, a sample tape of Comparative Example 34 was produced in the same manner as in Example 1 except that the calender conditions were set to be strong.

[0123]

[Table 6]

[0124] Comparative Example 35 lubricant 1 part by weight of (heptyl stearate), outside it calendar conditions that a medium, to prepare a sample tape of Comparative Example 35 in the same manner as in Comparative Example 34.

[0125] Comparative Example 36 lubricant 1 part by weight of (stearic acid heptyl), calendar conditions except that the weak, to prepare a sample tape of Comparative Example 36 in the same manner as in Comparative Example 34.

[0126] Comparative Example 37 lubricant (heptyl stearate) 2 parts by weight, except that the calendering conditions were strong, to prepare a sample tape of Comparative Example 37 in the same manner as in Comparative Example 34.

[0127] Comparative Example 38 lubricant 2 parts by weight (heptyl stearate), except that calendering conditions that a medium to prepare a sample tape of Comparative Example 38 in the same manner as in Comparative Example 34.

[0128] Comparative Example 39 lubricant 2 parts by weight (stearic acid heptyl), calendar conditions except that the weak, to prepare a sample tape of Comparative Example 39 in the same manner as in Comparative Example 34.

[0129] 3 parts by weight Comparative Example 40 lubricant (heptyl stearate), except that the calendering conditions were strong, to prepare a sample tape of Comparative Example 40 in the same manner as in Comparative Example 34.

[0130] Comparative Example 41 lubricant 3 parts by weight (heptyl stearate), except that calendering conditions that a medium to prepare a sample tape of Comparative Example 41 in the same manner as in Comparative Example 34.

[0131] Comparative Example 42 lubricant 3 parts by weight (heptyl stearate), calendar conditions except that the weak, to prepare a sample tape of Comparative Example 42 in the same manner as in Comparative Example 34.

[0132] 4 parts by weight Comparative Example 43 lubricant (heptyl stearate), except that the calendering conditions were strong, to prepare a sample tape of Comparative Example 43 in the same manner as in Comparative Example 34.

[0133] Comparative Example 44 lubricant 4 parts by weight (heptyl stearate), except that calendering conditions that a medium to prepare a sample tape of Comparative Example 44 in the same manner as in Comparative Example 34.

[0134] Comparative Example 45 lubricant 4 parts by weight (heptyl stearate), calendar conditions except that the weak, to prepare a sample tape of Comparative Example 45 in the same manner as in Comparative Example 34.

[0135] Comparative Example 46 lubricant (heptyl stearate) 5 parts by weight, except that the calendering conditions were strong, to prepare a sample tape of Comparative Example 46 in the same manner as in Comparative Example 34.

[0136] Comparative Example 47 lubricant 5 parts by weight (heptyl stearate), except that calendering conditions that a medium to prepare a sample tape of Comparative Example 47 in the same manner as in Comparative Example 34.

[0137] Comparative Example 48 lubricant 5 parts by weight (heptyl stearate), except that calendering conditions were weak, to prepare a sample tape of Comparative Example 48 in the same manner as in Comparative Example 34.

Example 32 A lubricant (heptyl stearate) was not added to a magnetic coating material, and a magnetic layer having a thickness of 2.0 μm was provided on a nonmagnetic support. Was coated in the same manner as in Example 10, except that the lubricant layer after drying was applied so that the thickness of the lubricant layer was 0.1 μm. Thus, a sample tape of Example 32 was produced.

Example 33 A lubricant (heptyl stearate) was added to a magnetic paint, and the magnetic paint was coated on a non-magnetic support with a thickness of 2.0 μm.
Was applied. Next, a sample tape of Example 33 was prepared in the same manner as in Example 10, except that a lubricant was applied on the magnetic layer so that the thickness of the lubricant layer after drying was 0.2 μm. .

Comparative Example 49 Instead of heptyl stearate as a lubricant, butyl palmitate was used, and 1 part by weight of the same was added. A sample tape was prepared.

[0141] Comparative Example 50 lubricant 1 part by weight (butyl palmitate), except that calendering conditions that a medium to prepare a sample tape of Comparative Example 50 in the same manner as in Comparative Example 49.

[0142] Comparative Example 51 lubricant 1 part by weight (butyl palmitate), except that calendering conditions were weak, to prepare a sample tape of Comparative Example 51 in the same manner as in Comparative Example 49.

[0143] Comparative Example 52 lubricant (butyl palmitate) 2 parts by weight, except that the calendering conditions were strong, to prepare a sample tape of Comparative Example 52 in the same manner as in Comparative Example 49.

[0144] Example 34 lubricant 2 parts by weight (butyl palmitate), except that calendering conditions that a medium to prepare a sample tape of Example 34 in the same manner as in Comparative Example 49.

[0145] Example 35 lubricant 2 parts by weight (butyl palmitate), except that calendering conditions were weak, to prepare a sample tape of Example 35 in the same manner as in Comparative Example 49.

[0146] Example 36 the lubricant, 3 parts by weight of (butyl palmitate), except that the calendering conditions were strong, to prepare a sample tape of Example 36 in the same manner as Comparative Example 49.

[0147] Example 37 lubricant 3 parts by weight (butyl palmitate), except that calendering conditions that a medium to prepare a sample tape of Example 37 in the same manner as in Comparative Example 49.

[0148] Example 38 lubricant 3 parts by weight (butyl palmitate), except that calendering conditions were weak, to prepare a sample tape of Example 38 in the same manner as in Comparative Example 49.

[0149] Example 39 lubricant 4 parts by weight (butyl palmitate), except that the calendering conditions were strong, to prepare a sample tape of Example 39 in the same manner as in Comparative Example 49.

[0150] Example 40 lubricant 4 parts by weight (butyl palmitate), except that calendering conditions that a medium to prepare a sample tape of Example 40 in the same manner as in Comparative Example 49.

[0151] Example 41 lubricant 4 parts by weight (butyl palmitate), except that calendering conditions were weak, to prepare a sample tape of Example 41 in the same manner as in Comparative Example 49.

[0152] Example 42 lubricant 5 parts by weight (butyl palmitate), except that the calendering conditions were strong, to prepare a sample tape of Example 42 in the same manner as in Comparative Example 49.

[0153] Comparative Example 53 lubricant 5 parts by weight (butyl palmitate), except that calendering conditions that a medium to prepare a sample tape of Comparative Example 53 in the same manner as in Comparative Example 49.

[0154] Comparative Example 54 lubricant 5 parts by weight (butyl palmitate), calendar conditions except that the weak, to prepare a sample tape of Comparative Example 54 in the same manner as in Comparative Example 49.

Comparative Example 55 The same procedure as in Example 10 was carried out except that butyl palmitate was used as the lubricant instead of heptyl stearate, and 1 part by weight of butyl palmitate was added. A sample tape was prepared.

[0156] Comparative Example 56 lubricant 1 part by weight (butyl palmitate), except that calendering conditions that a medium to prepare a sample tape of Comparative Example 56 in the same manner as in Comparative Example 55.

[0157] Comparative Example 57 lubricant 1 part by weight of (palmitate butyl), except that calendering conditions were weak, to prepare a sample tape of Comparative Example 57 in the same manner as in Comparative Example 55.

[0158] Comparative Example 58 lubricant (butyl palmitate) 2 parts by weight, except that the calendering conditions were strong, to prepare a sample tape of Comparative Example 58 in the same manner as in Comparative Example 55.

[0159] Example 43 lubricant 2 parts by weight (butyl palmitate), except that calendering conditions that a medium to prepare a sample tape of Example 43 in the same manner as in Comparative Example 55.

[0160] Example 44 lubricant 2 parts by weight (butyl palmitate), except that calendering conditions were weak, to prepare a sample tape of Example 44 in the same manner as in Comparative Example 55.

[0161] Example 45 lubricant 3 parts by weight (butyl palmitate), except that the calendering conditions were strong, to prepare a sample tape of Example 45 in the same manner as in Comparative Example 55.

[0162] Example 46 lubricant 3 parts by weight (butyl palmitate), except that calendering conditions that a medium to prepare a sample tape of Example 46 in the same manner as in Comparative Example 55.

[0163] Example 47 lubricant 3 parts by weight (butyl palmitate), except that calendering conditions were weak, to prepare a sample tape of Example 47 in the same manner as in Comparative Example 55.

[0164] Example 48 4 parts by weight of lubricant (butyl palmitate), except that the calendering conditions were strong, to prepare a sample tape of Example 48 in the same manner as in Comparative Example 55.

[0165] Example 49 lubricant 4 parts by weight (butyl palmitate), except that calendering conditions that a medium to prepare a sample tape of Example 49 in the same manner as in Comparative Example 55.

[0166] Example 50 4 parts by weight of lubricant (butyl palmitate), except that calendering conditions were weak, to prepare a sample tape of Example 50 in the same manner as in Comparative Example 55.

[0167] Example 51 lubricant 5 parts by weight (butyl palmitate), except that the calendering conditions were strong, to prepare a sample tape of Example 51 in the same manner as in Comparative Example 55.

[0168] Comparative Example 59 lubricant 5 parts by weight (butyl palmitate), except that calendering conditions that a medium to prepare a sample tape of Comparative Example 59 in the same manner as in Comparative Example 55.

[0169] Comparative Example 60 lubricant 5 parts by weight (butyl palmitate), except that calendering conditions were weak, to prepare a sample tape of Comparative Example 60 in the same manner as in Comparative Example 55.

Comparative Example 61 Instead of heptyl stearate as a lubricant, butyl palmitate was used, and 1 part by weight of the same was added. A sample tape was prepared.

[0171] Comparative Example 62 lubricant 1 part by weight (butyl palmitate), except that calendering conditions that a medium to prepare a sample tape of Comparative Example 62 in the same manner as in Comparative Example 61.

[0172] Comparative Example 63 lubricant 1 part by weight (butyl palmitate), calendar conditions except that the weak, to prepare a sample tape of Comparative Example 63 in the same manner as in Comparative Example 61.

[0173] Comparative Example 64 lubricant (butyl palmitate) 2 parts by weight, except that the calendering conditions were strong, to prepare a sample tape of Comparative Example 64 in the same manner as in Comparative Example 61.

[0174] Comparative Example 65 lubricant 2 parts by weight (butyl palmitate), except that calendering conditions that a medium to prepare a sample tape of Comparative Example 65 in the same manner as in Comparative Example 61.

[0175] Comparative Example 66 lubricant 2 parts by weight (butyl palmitate), calendar conditions except that the weak, to prepare a sample tape of Comparative Example 66 in the same manner as in Comparative Example 61.

[0176] 3 parts by weight Comparative Example 67 lubricant (butyl palmitate), except that the calendering conditions were strong, to prepare a sample tape of Comparative Example 67 in the same manner as in Comparative Example 61.

[0177] Comparative Example 68 lubricant 3 parts by weight (butyl palmitate), except that calendering conditions that a medium to prepare a sample tape of Comparative Example 68 in the same manner as in Comparative Example 61.

[0178] Comparative Example 69 lubricant 3 parts by weight (butyl palmitate), calendar conditions except that the weak, to prepare a sample tape of Comparative Example 69 in the same manner as in Comparative Example 61.

[0179] 4 parts by weight Comparative Example 70 lubricant (butyl palmitate), except that the calendering conditions were strong, to prepare a sample tape of Comparative Example 70 in the same manner as in Comparative Example 61.

[0180] Comparative Example 71 lubricant 4 parts by weight (butyl palmitate), except that calendering conditions that a medium to prepare a sample tape of Comparative Example 71 in the same manner as in Comparative Example 61.

[0181] 4 parts by weight Comparative Example 72 lubricant (butyl palmitate), except that the calendering conditions were strong, to prepare a sample tape of Comparative Example 72 in the same manner as in Comparative Example 61.

[0182] 5 parts by weight Comparative Example 73 lubricant (butyl palmitate), except that the calendering conditions were strong, to prepare a sample tape of Comparative Example 73 in the same manner as in Comparative Example 61.

[0183] Comparative Example 74 lubricant 5 parts by weight (butyl palmitate), except that calendering conditions that a medium to prepare a sample tape of Comparative Example 74 in the same manner as in Comparative Example 61.

[0184] Comparative Example 75 5 parts by weight of a lubricant (butyl palmitate), except that calendering conditions were weak, to prepare a sample tape of Comparative Example 75 in the same manner as in Comparative Example 61.

COMPARATIVE EXAMPLE 76 Instead of heptyl stearate as a lubricant, butyl palmitate was used, and 1 part by weight of the same was added. A sample tape was prepared.

[0186] Comparative Example 77 lubricant 1 part by weight (butyl palmitate), except that calendering conditions that a medium to prepare a sample tape of Comparative Example 77 in the same manner as in Comparative Example 76.

[0187] Comparative Example 78 lubricant 1 part by weight (butyl palmitate), except that calendering conditions were weak, to prepare a sample tape of Comparative Example 78 in the same manner as in Comparative Example 76.

[0188] Comparative Example 79 lubricant (butyl palmitate) 2 parts by weight, except that the calendering conditions were strong, to prepare a sample tape of Comparative Example 79 in the same manner as in Comparative Example 76.

[0189] Comparative Example 80 lubricant 2 parts by weight (butyl palmitate), except that calendering conditions that a medium to prepare a sample tape of Comparative Example 80 in the same manner as in Comparative Example 76.

[0190] Comparative Example 81 lubricant 2 parts by weight (butyl palmitate), calendar conditions except that the weak, to prepare a sample tape of Comparative Example 81 in the same manner as in Comparative Example 76.

[0191] 3 parts by weight Comparative Example 82 lubricant (butyl palmitate), except that the calendering conditions were strong, to prepare a sample tape of Comparative Example 82 in the same manner as in Comparative Example 76.

[0192] Comparative Example 83 lubricant 3 parts by weight (butyl palmitate), except that calendering conditions that a medium to prepare a sample tape of Comparative Example 83 in the same manner as in Comparative Example 76.

[0193] Comparative Example 84 lubricant 3 parts by weight (butyl palmitate), outside it calendar conditions were weak, to prepare a sample tape of Comparative Example 84 in the same manner as in Comparative Example 76.

[0194] 4 parts by weight Comparative Example 85 lubricant (butyl palmitate), except that the calendering conditions were strong, to prepare a sample tape of Comparative Example 85 in the same manner as in Comparative Example 76.

[0195] Comparative Example 86 lubricant 4 parts by weight (butyl palmitate), except that calendering conditions that a medium to prepare a sample tape of Comparative Example 86 in the same manner as in Comparative Example 76.

[0196] Comparative Example 87 lubricant 4 parts by weight (butyl palmitate), except that calendering conditions were weak, to prepare a sample tape of Comparative Example 87 in the same manner as in Comparative Example 76.

[0197] 5 parts by weight Comparative Example 88 lubricant (butyl palmitate), except that the calendering conditions were strong, to prepare a sample tape of Comparative Example 88 in the same manner as in Comparative Example 76.

[0198] Comparative Example 89 lubricant 5 parts by weight (butyl palmitate), except that calendering conditions that a medium to prepare a sample tape of Comparative Example 89 in the same manner as in Comparative Example 76.

[0199] Comparative Example 90 lubricant 5 parts by weight (butyl palmitate), except that calendering conditions were weak, to prepare a sample tape of Comparative Example 90 in the same manner as in Comparative Example 76.

Example 52 A lubricant (butyl palmitate) was not added to a magnetic coating material, and a magnetic layer having a thickness of 2.0 μm was provided on a nonmagnetic support. Was applied in such a manner that the thickness of the lubricant layer after drying was 0.1 μm, to thereby prepare a sample tape of Example 52 in the same manner as in Comparative Example 55.

Example 53 A lubricant (butyl palmitate) was added to a magnetic coating material in an amount of 3 parts by weight, and the magnetic coating material having a thickness of 2.0 was coated on a nonmagnetic support.
μm was applied. Next, a sample tape of Example 53 was prepared in the same manner as in Comparative Example 55, except that a lubricant was applied on this magnetic layer so that the thickness of the lubricant layer after drying was 0.1 μm. .

Each of the sample tapes prepared as described above was evaluated for lubricant extraction, high-temperature oxidation stability, output deterioration measurement, still characteristics, and friction measurement by the following methods.

<Measurement of Extraction Amount> Each sample tape obtained as described above was cut off by 5 m and placed in a conical beaker. 120 cc of n-hexane was measured into the conical beaker with a measuring cylinder, covered, and immersed for 5 minutes. After adding n-hexane, the mixture was stirred for 30 seconds at 1 minute and 4 minutes. Five minutes later, 100 cc was measured with a measuring cylinder, placed in a beaker, and left in a fume hood to evaporate n-hexane. In the evaporated beaker, acetonitrile:
5 cc of water = 100: 5 was added with a pipettor, and dissolved in an ultrasonic cleaner for 1 minute. Then, the solution was put into a sample bottle with a syringe in this beaker, and measurement was performed by an ODS reverse phase column by HPLC using a detector RI.

<Estimated high-temperature oxidation rate> The high-temperature oxidation stability rate is TG
Using DTA (EXSTAR6000 series, manufactured by Seiko Instruments Inc.), the temperature was raised to 200 ° C. at 100 ° C./min in an N ₂ atmosphere, and then N
The change in TG when the sample was kept for 30 minutes in an atmosphere of ₂ (80%) + O ₂ (20%) was measured. Further, the value obtained when the TG was sufficiently oxidized and the TG was saturated was defined as the TG after the complete oxidation reaction, and the value obtained by dividing the TG from 100 ° C. to 200 ° C. by that value was defined as the high-temperature oxidation rate.

<Measurement of output deterioration> A temperature of 40 ° C. and a relative humidity of 65% RH were measured using an 8 mm video recorder manufactured by Sony Corporation.
The tape was allowed to run for 4 hours under the environment described above, and the difference between the initial RF output and the RF output after running for 4 hours was measured. And, when the output deterioration is 1.5 dB or less, ○, 1.5 dB or more,
未 満 for less than 2.5 dB and × for more than 2.5 dB
And

<Still Characteristics> Using an 8 mm video recorder manufactured by Sony which has been modified so that still can be performed for a long time, the time from the initial stage until the RF output attenuates by 3 dB in an environment of a temperature of 40 ° C. and a relative humidity of 80% RH Was determined as the still time. Three measurements were performed for one sample, and the average value was calculated. And, when the still property is 300 minutes or more, ○, when the still property is 100 minutes or more and less than 200 minutes, Δ
A sample having a duration of less than 00 minutes was evaluated as x.

<Measurement of friction> The friction was measured using a tape friction measuring machine manufactured by Sony Corporation. Then, run a 100-pass tape, and if the increase in friction is 10% or less, ○, the increase in friction is 20%
The following were rated as △, and those that did not finish due to tape attachment were rated as ×.

The above results are shown in Tables 7 and 8 below.

[0209]

[Table 7A] * Lubricants: fatty acid esters (hereinafter the same)

[0210]

[Table 7B]

[0211]

[Table 8A]

[0212]

[Table 8B]

As is clear from Tables 7 and 8, the magnetic recording media of Examples 1 to 50 according to the present invention
Since the high-temperature oxidation stability of the magnetic powder, which is a component of the magnetic layer, by thermal analysis is 50% or less, even in an environment in which high-temperature frictional heat is generated when the head and the medium slide, for example, Generation of a certain oxide was suppressed, and output deterioration was able to be suppressed. The amount of the lubricant extracted with n-hexane is 20 to 100 mg / m ^2.
, It had excellent still characteristics and durability. Therefore, it was possible to achieve both suppression of output deterioration due to burn-in between the head and the medium and improvement in still characteristics and durability.

On the other hand, when the high-temperature oxidation stability of the magnetic powder by thermal analysis was 50% or less and the amount of the lubricant extracted with n-hexane was less than 20 mg / m ² , Although excellent in suppressing output deterioration,
Since the amount of the lubricant extracted by n-hexane was too small, the friction characteristics were deteriorated and the still characteristics could not be improved. If the high-temperature oxidation stability of the magnetic powder by thermal analysis is 50% or less, and the amount of the lubricant extracted with n-hexane exceeds 100 mg / m ² , the running reliability is increased due to an increase in friction. Dropped. further,
When the amount of the lubricant extracted by n-hexane is 20 to
When it is within the range of 100 mg / m ² and the high-temperature oxidation stability of the magnetic powder by thermal analysis exceeds 50%,
Although it had good still characteristics, it was difficult to suppress the generation of oxides, and output deterioration increased.

[0215]

According to the present invention, since the high-temperature oxidation stability of the magnetic powder by thermal analysis is 50% or less, even in an environment in which high-temperature frictional heat is generated when the head and the medium slide, for example, In addition, generation of oxides as burn-in products is suppressed, and output deterioration can be suppressed.

Further, since the lubricant is retained in and / or on the magnetic layer and the amount of the lubricant extracted by n-hexane is specified to be ²⁰ to 100 mg / m ² , excellent still Has properties and durability.

Therefore, the magnetic recording medium of the present invention can achieve both suppression of output deterioration due to burn-in between the head and the medium and improvement in still characteristics and durability.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a magnetic recording medium according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Magnetic recording medium, 2 ... Non-magnetic support, 3 ... Magnetic layer, 4
… Back coat layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // C10N 30:00 C10N 30:00 Z 40:18 40:18

Claims (6)

[Claims] 1. A magnetic powder which contains a lubricant in and / or on a magnetic layer, has a high-temperature oxidation stability of 50% or less by thermal analysis of magnetic powder as a constituent of the magnetic layer, and is extracted with n-hexane. The amount of the lubricant is 20 to 100 mg /
It is m ^2, and the magnetic recording medium. 2. The magnetic recording medium according to claim 1, wherein an amount of the lubricant extracted by the n-hexane is an amount of the lubricant existing in a surface area of the magnetic layer. 3. The lubricant is a fatty acid ester,
The magnetic recording medium according to claim 1. 4. The magnetic recording medium according to claim 3, wherein the fatty acid ester is an ester compound comprising a higher fatty acid having 16 to 22 carbon atoms and neopentyl alcohol. 5. The fatty acid ester comprises a monobasic fatty acid having 10 or more and 24 or less carbon atoms (however, it may be branched or may contain an unsaturated bond) and has one or more carbon atoms. 4. The magnetic recording according to claim 3, which is an ester compound comprising a monohydric alcohol of 18 or less (however, it may be branched or may contain an unsaturated bond) or a monoalkyl ether of an alkylene oxide. Medium. 6. The magnetic recording medium according to claim 1, wherein said magnetic powder is a ferromagnetic fine metal powder.