JPS58194130A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To enhance magnetic characteristics and wear resistance and to provide long-term shelf stability, by incorporating a specified compound into the magnetic recording layer on the surface of the support. CONSTITUTION:A compound represented by a general formula I is incorporated into a magnetic recording layer on the surface of a support. In the formula, R is optionally substituted alkyl, alkenyl or aryl, and each R' is H or alkyl, yet all of four R's are not H.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to magnetic recording media such as magnetic tapes and magnetic sheets, and particularly to high-density magnetic recording media that have good wear resistance, storage stability, and high playback output. It is.

Conventionally, in magnetic recording media such as recording tapes and audiotapes, s k'ez04 s )'e -0o-N
I mixed magnetic powder with vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer, polybutyl acrylate, 7-acrylic acid notyl-acrylate)! A coating solution is obtained by separating and kneading a binder such as a lulu copolymer, cellulose oil removal, evogin resin, or polyurethane concentrate, polyethylene terephthalate, cellulose triacetate, polycarbonate, polypropylene, polyester, etc. It was placed on a film-like nonmagnetic support such as vinyl chloride. By using these binders alone or in combination,
The dispersibility of the magnetic powder in the binder is poor due to insufficient moisture between the six sides of the magnetic powder particles and the binder, and the shape of the magnetic powder particles having acicular crystals. Therefore, in order to obtain the desired magnetic properties in conventional magnetic recording media, it is necessary to have other properties in addition to the magnetic recording media, such as abrasion resistance and storage stability. was not fully satisfied.

In particular, in video tapes that are required to be able to record short wavelengths, poor dispersion of magnetic powder in the magnetic layer leads to deterioration of the SIN ratio and decrease in sensitivity. Due to the repeated use, the magnetic coating was worn out, and the magnetic powder contained in the coating was likely to fall off, giving rise to undesirable results such as clogging of the magnetic head.

For this reason, various additives are used to control the particle size distribution of magnetic powder [7], improve the dispersibility of magnetic powder in a binder, and improve wear resistance. For example, Special Publications No. 41-18064, No. 43-186, No. 43-
No. 669, No. 47-15624, JP-A-49-534
02, No. 49-58804, No. 49-84405, No. 51-40904, and No. 52-70811, magnetic powder dispersion paint containing magnetic powder and binder as described in It contains higher fatty acids, fatty acid esters, fatty acid esters, higher alcohols, metal soaps, higher alcohol sulfuric esters, polyethylene oxide, lecithin, etc., and this magnetic powder dispersion is coated on the surface of a non-magnetic support. Nowadays, magnetic recording media are being manufactured.

However, even with the addition of these additives, the improvement of magnetic properties,
It has been difficult to obtain a magnetic recording medium having desirable characteristics in terms of wear resistance, long-term storage stability, and the like. For example, if a large amount of these additives is used, the mechanical strength of the magnetic recording layer will decrease, which is an undesirable result. A so-called pluming phenomenon occurs in which the additive gradually oozes out onto the surface, and tackiness is observed, resulting in undesirable results in terms of storage stability. In addition, the dispersibility of magnetic powder, the i of magnetic recording
Her sexual characteristics were also far from satisfactory.

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel magnetic recording medium that overcomes the various drawbacks of the 11th century.

Another object of the present invention is to provide a wear-resistant and wear-resistant magnetic recording medium.

Still another object of the present invention is to provide a magnetic recording medium with a good S/N ratio.

Still another object of the present invention is to provide a magnetic recording medium with high reproduction output.

Still another object of the present invention is to provide a high quality magnetic recording medium with excellent storage stability.

The above-mentioned objective of the present invention is achieved by a magnetic recording medium in which the magnetic recording layer on the surface of the support contains a compound represented by the following general formula 0 (hereinafter referred to as the compound of the present invention). Ru.

In the general formula (KO), P-Ugly1ゝ(R')4 General formula 0], R is an alkyl group, preferably an alkyl group having 5 to 30 carbon atoms (for example, an octyl group, a decyl group, a dodecyl group, octadecyl &), alkenyl group,
Preferably vertical IA atom #I! 15 to 30 alkenyl groups (e.g., octenyl group, oleyl group), aryl groups (e.g., phenyl group), R' is a hydrogen atom or an alkyl group, each of which may be different, and preferably has 1 to 4 carbon atoms. 10% of the furkyl group preferably represents a furkyl group having 1 to 4 carbon atoms (eg, methyl group, butyl group). However, the four R's are never hydrogen atoms f at the same time.

Furthermore, the RO and R' lines may be the same group (or atom) or may be different groups (or atoms).

In the present invention, each of the above groups may have an arbitrary substituent. Typical substituents include a halogen atom (eg, fluorine atom), an alkyl group (eg, octyl group, dodecyl group, stearyl group), and an alkenyl group (eg, butenyl group, oleyl group).

Examples include 1-aryl groups (for example, phenyl 4), and preferably 1-fluorine-substituted alkyl groups, particularly fluorine-substituted alkyl groups having 2 to 10 carbon atoms (for example, perfluoropentyl group).

Next, a specific example of the compound of the present invention will be given, but the compound of the present invention is not limited thereto.

Exemplary Compounds] (01)4B,0)a P -ON (OH,)4(
2) 0 (8) 0 (荀 0 (6) O (6) 0 (7) O There is.

1. Synthesis example of exemplified compound (1) 31 t of sodium dioleyl phosphate and 5.5 f of detramethyl 7 ammonium chloride were dissolved in 200 g of water, heated under gentle reflux for 1 hour with stirring, cooled, and then dried under reduced pressure. Solidify and extract with n-hexane (repeat,
7.2 Synthesis example of exemplified compound (2) didodecylphenyl phosphorus #25 fk metal 7-ol 200
- triethylamine 5.059 while stirring
When added, it becomes cloudy. If this reaction mixture is drawn as a chain line, e
, target product 292 as a wet viscous solid (97% yield)
get.

In addition to the above, the compound of the present invention can be easily synthesized according to the description in Ryohei Oda's "Synthesis of Surfactants and Their Applications" (published by Asakura Shoten).

These compounds of the present invention may be used alone or in combination of two or more.

The magnetic powder used in the present invention is a fine powder having a major axis of magnetic metal powder of 0.1 μ to 1 μ. Examples of magnetic metal include metals such as iron, nickel, and cobalt, aluminum, cobalt, iron, Alloys and mixtures of metals such as lead, magnesium, nickel, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium, aluminum oxide, iron oxide, steel oxide, nickel oxide ,
Zinc oxide! I! Examples include metal compounds containing metal oxides such as titanium oxide and magnesium oxide, and ferromagnetic substances such as ferrite. Mainly used are fine powders of ferromagnetic metals such as ferrite and iron-cobalt-nickel alloys.

In order to incorporate the compound of the present invention together with magnetic powder into a magnetic powder dispersion paint, at least one compound of the present invention is dissolved in a solvent such as toluene, methyl ethyl ketone, ethyl sepsolp, acetone, methanol, etc. After soaking the magnetic powder at a ratio of This results in Asahi 1m magnetic powder that can be easily wetted and dispersed in the agent.

Alternatively, at least one compound of the present invention may be added to the magnetic powder-dispersed paint directly or dissolved in a suitable solvent.

The compound of the present invention is usually 7 o per 100 parts by weight of magnetic powder.
, s11 parts to 30i parts, preferably 0.5 parts to 30i parts
It is preferable to use it within the range of 10 weights.

If the amount of the compound of the present invention is less than 0.5 parts by weight, the effect of the present invention will not be significant, and if it exceeds 30 parts by weight, a plumping phenomenon may occur, giving unfavorable results.

Generally magnetic powder dispersion I! The main components of the I material are ferromagnetic powder, a binder, the compound of the present invention, and a coating solvent.
Depending on the case, a dispersing agent, an 841w agent, an abrasive, an antistatic agent, and other additives may be included. This magnetic powder-dispersed paint is prepared by dissolving and dispersing the above-mentioned composition in an organic solvent, and is coated onto the surface of the non-magnetic support to form a magnetic recording layer.

Regarding the manufacturing method of the magnetic powder dispersion paint used in the present invention, please refer to Japanese Patent Publications No. 35-15, No. 39-26794, No. 43-1.
No. 86, No. 47-28043, No. 47-28045, No. 47-28046, No. 47-28048, No. 4
No. 7-31445, No. 48-11162, No. 48-
It is described in detail in various publications such as No. 21331, No. 48-33683, and Soviet Patent Specification No. 308033.

As the binder used in the present invention, conventionally known thermoplastic resins, thermosetting resins, reactive resins, and mixtures thereof are used.

The thermoplastic resin has a softening temperature of 150 or less and an average molecular diameter of 10,000 to 200,000. The degree of polymerization is about 2
00 to 200011 degrees, such as vinyl chloride-vinyl acetate copolymer, vinyl chloride/L, -vinylidene chloride copolymer, vinyl chloride-chloronitrile copolymer, acrylic acid ester=1 crylonitrile copolymer, Acrylic ester-vinylidene chloride copolymer, acrylic ester-styrene copolymer, methacrylic ester-7
Acrylonitrile copolymer, methacrylic acid ester-vinylidene chloride copolymer, methacrylic acid ester-styrene copolymer, urethane elastomer, polyvinyl fluoride, vinylidene chloride-1-crylonitrile co-1 polymer, acrylonitrile-butadiene copolymer , polyamide 411 resin, polyvinyl butyral, cellulose cast conductor (cellulose acetate styrate, cellulose diacetate, cellulose triacetate, cellulose pluvionate, 2) ET cellulose, etc.), stainless-putadiene copolymer, polyester resin, resin 17hi vinyl ether-acrylic acid ester comonomer, amino resin, various synthetic rubber-based thermoplastic resins, and mixtures thereof are used.

These resins are disclosed in Japanese Patent Publications Nos. 37-6877 and 39-1.
No. 2528, 39-192824. Same 40-5349
No. 40-20907, No. 41-9463, No. 4
No. 1-14059, No. 41-16985, No. 42-6
No. 428, No. 42-11621, No. 43-4623, No. 43-15206, No. 44-2889, No. 44
-17947, 44-18232, 45-14
No. 020, No. 45-14500, No. 47-18573
No. 47-22063, No. 47-22064, No. 47-22068, No. 47-22069, No. 47-
No. 22070, US Patent No. 48-27886, US Patent No. 3,144,352, US Patent No. 3,419,420,
It is described in the specifications of the same No. 3,499.789 and the same No. 3,713,887.

The thermosetting resin or the reactive resin has a molecular weight of 200,000 or less in the state of a coating liquid, and after coating and drying, it becomes a polymer through reactions such as incorporation and addition, and the molecular weight becomes infinite. Moreover, among these thermosetting resins or reactive resins, those that do not soften or melt before the resin is polymerized are preferred. Specifically, for example, phenol resin, epoxy resin, polyurethane curable resin, urea resin, melamine resin, alkyd resin, silicone resin, acrylic reaction resin, high molecular weight polynystyl lubricant and insifnate prepolymer σ) mixture! #! J, mixture of methacrylate co-1 and diisocyphnate prepolymer, polyester polyol and polyisocyanate
, mixtures of original formaldehydol/triphenylmethane tri-r-socyanate, poly-fE resins, and mixtures thereof.

These 11 fats are listed in Japanese Patent Publication No. 39-8103 and No. 40-
No. 9779, No. 41-7192, No. 41-81J16
No. 41-14275, No. 42-18179, No. 43-12031, No. 44-28023, No. 45-
1450.1, 45-24'j02, 46-1
No. 3103, No. 47-22u67-+, No. 47-
2 2 13 7 No. 2, No. 47-22073, No. 4
No. 7-28045, No. 47-28048, No. 44-2
8023 publications, U.S. Patent No. 3.1 4 4.3 5
3%, same No. 3,320,090, same No.3,
No. 437,510, same No. 3, 597, 27
No. 3, No. 3,781,21, No. 3,7 8 1
, 211 specification.

These binders may be used alone or in combination, and if necessary, other Km additives may be added. Mixing ratio of ferromagnetic powder and binder Adhesive 10-400 parts by weight preferably 30
If the binder is used in the range of ~200 parts by weight, too much of the binder will lower the arrangement density when used as a magnetic recording medium, and if too little, the strength of the magnetic recording layer will be poor, the durability will be reduced, and
&Unfavorable fist stiffness such as dropping occurs.

In addition to the compound of the present invention, a binder, and the ferromagnetic powder, additives such as a dispersant, a lubricant, an abrasive, and an antistatic agent are added to the magnetic powder-dispersed paint that forms the magnetic recording layer. Good too.

Dispersants that may be used include caprylic acid.

Fats with 12 to 18 carbon atoms (R
,0OOH, R1 is an alkyl group having 11 to 17111 carbon atoms);
a+) or alkaline earth metals (Mg, Oa, B
A metal soap consisting of (a) etc. is used; In addition, higher alcohols having 12 or more longitudinal atoms and sulfuric esters may also be used. These dispersants are added in an amount of 1 to 20 parts per 100 parts of the binder.

These dispersants are disclosed in Japanese Patent Publication Nos. 39-28369 and 44
-17945, 11148-15001 Publications 1 U.S.% Peak No. 3.587.993, No. 3,470.02
1Q It is stated in each specification.

@f# M includes silico/oil, carbon blank, graphite, carbon black graft polymer, molypide disulfide/, tanges disulfide j), carbon tA monobasic fatty acid with 12 to 1 atoms, and the fatty acid in the fatty region. Fatty acid esters (so-called μ) made of monohydric alcohols having 21 to 23 longitudinal atoms together with the number of longitudinal atoms can also be used. These lubricants are added in an amount of 0.2 to 20 JIJt parts based on lOθ electric m parts of the binder. Regarding these, Japanese Patent Publication No. 43-23889, No. 43
-81543 fathom 1 publication, U.S. Patent No. 3.470.0
No. 21, No. 3.492.235, No. 3,497,
No. 411, No. 3,523.086, No. 3,625
, No. 760, No. 3,630.772, No. 3,63
No. 4.253, No. 3,642,539, No. 3.6
87.725, IBM Technica
l Disclosure Bu eyes @hin Vol-9
, N17, Pag@779 (December 1966)
: ELEKTRONIK 1961 NILI 2
.

It is described in Page 380 etc.

The abrasives used are commonly used materials such as fused alumina, expanded silicon chromium oxide, corundum, artificial corona/dam, diamond, artificial diamond, garnet, and emery (main ingredients: corundum and magnetite). Ru. These abrasives have an average particle size of 0.05 to 5 .mu.m, particularly preferably 0.1 to 2 .mu.m. These abrasives are used in an amount of 7 parts by weight per 100 parts by weight of the binder.
It is added in a range of 201 parts to 201 parts. These abrasives are disclosed in Japanese Unexamined Patent Publication No. 11EI49-115510, U.S. Patent No. 3.007.807, U.S. Pat.
Patent No. 3,687,725, British Patent No. 1.1
45.349 and West German Patent (DT-PS) No. 853.211. .

Antistatic agents and E2 used include conductive powders such as graphite, carbon black, and carbon black grafted polymers; natural surfactants such as saponins; 7
7-ion surfactants such as /l-molecular oxide type, glycerin type, glycidol type; cationic external activity such as higher alkylaj7 types, quaternary l memonium salts, bilin, other *cumulative types, phosphonium or sulfonium types agent; 7-ionic surfactant containing acidic groups such as carboxylic acid, sulfonate acid, phosphoric acid, its ester group, phosphoric acid ester group; 74 groups, aminosulfonic acids, 1
Amphoteric activators such as sulfuric acid or phosphoric acid esters of minol alcohol are used.

These surfactants that can be used as antistatic agents are disclosed in U.S. Pat.
No. 2,676.924, No. 2,676.97
No. 5, No. 2,691,566, No. 2.727.8
No. 60, No. 2,730,498, No. 2,742,
No. 379, No. 12,739,891, No. 3,068
, No. 101, No. 3,158,484, No. 3, 20
No. 1,253, No. 3,210,191, No. 3,2
No. 94,540, No. 3,415,649, No. 3,
No. 441,413, No. 3.442,654, No. 3
, 475.174, 3,545,974, West German Patent Publication (Ou8) No. 1,942,66
Specification No. 5, British Pestle @ No. 1,077.317, No. 1
．． 198,450, etc., Ryohei Oda et al.'s ``Synthesis of Surfactants and Their Applications'' (Maki Shoten 1964 edition); 1958 edition) BT, P, 7th pickpocket
encyclopedia op Φ surface active
Agents, Volume 2 J (Chemical Publishing Company, 1964, 14 [i); Handbook of External Activators, No. 6
It is written on the bottom of the print (Sangyo Tosho Co., Ltd., December 20, 1960).

These surfactants may be added singly or in combination. Although these are used as antistatic agents, they are sometimes used for other purposes such as dispersion, improving magnetic properties, improving #4 slipperiness, and as coating aids.

The magnetic recording layer is formed by dissolving the above composition in an organic solvent,
Coat it on the surface of a non-magnetic support as a coating solution.

Organic solvents used during coating include ketones such as 7setone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; alcohols such as methanol, ethanol, purpanol, and butanol; methyl acetate, ethyl acetate, butyl acetate, ethyl lactate, and acetic acid. Ester systems such as glycol monoethyl ether; glycol ether systems such as diethyl ether, glycol dimethyl ether, glycol monoethyl ether, and dioxane; tar systems (aromatic hydrocarbons) such as benzene, toluene, and xylene;
chlorinated aspect ratio hydrogen such as notylene coolide, etele/lypride, carbon tetrachloride, chloroform, ethylene flurhydrin, dichlorobenzene, etc. can be used.

The material for the support may be any non-magnetic material, such as polynisdels such as polyethylene terephthalate and polyethylene-2,6-7-talate, polyolefins such as polypropylene, cellulose triacetate, cellulose p-sdai Cellulose haze conductor such as 7-tate,
Plastics such as polycarbonate, Ou, kl,
Non-magnetic metals such as Zn, glass, porcelain, ceramics such as earthenware, etc. are used.

The thickness of these non-magnetic supports is approximately 3 to 100 μIn in the case of a film or sheet, preferably 5 to 50 μIn.
n, and in the case of disks and cards, 0.5 to 10
am, and in the case of a drum shape, it is cylindrical, and its shape is determined depending on the recorder used.

The above-mentioned non-magnetic support may be coated with a so-called back coat on the surface opposite to the surface on which the magnetic layer is provided for the purpose of preventing soldering or transfer.

Regarding the back coat, for example, US Special Forces No. 2.80
No. 4,401, No. 3,293,066, No. 3.6
No. 17,378, same No. 3. (No. 162,676, No. 3.734.772, No. 3,476.596, No. 2.643.048, No. 2,803.5564,
Same No. 2, 887.462, Same No. 2,923.642, Same No. 2.997,451, Same No. 3,007,892
g, same No. 3.041.196, same cylinder 3,115,42
ml is listed in each specification such as No. 0 and No. 3.166.688.

The support may be in any form such as a tape, sheet, card, disk, or drum, and various materials may be selected depending on the form.

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

In one kneading, the magnetic powder and the above-mentioned components are all added to the mixing wire simultaneously or one after another. For example, there is a method in which magnetically dispersed wood is first added to a liquid containing a dispersant and kneaded for a predetermined period of time, and then the remaining components are added and mixed continuously to obtain a magnetically dispersed paint.

Various types of crosstalk machines h' are used for crosstalk distribution.

For example, two-roll mill, three-roll mill, ball s/
L, Pebble Mill, Sand Grinder, Szegva
ri 7) Lighter, high-speed impeller disperser, high-speed Stono mill, high-speed impact mill, Tishar kneader, A
d mixer, homogenizer-1 ultrasonic separation machine, etc.

The technology related to crosstalk dispersion is T, O, FAT'l'CJ
F'aint l'low and by N
Pigment Dispersion (196
Published by John W. Ley & 5ons, Inc.). Also, U.S. Patent No. 2,581,414
It is also mentioned in the specifications of No. 2, No. 855.156.

The magnetic powder-dispersed paint is overlaid on a non-magnetic support.

As a coating method for forming a magnetic recording layer,
-Doctor coat, Blade-1, Engineering Knife coat, Squeeze coat, Impregnation coat, Reverse rule coat, Transfer rule coat, Graphic coat,
Kiss coat, cast coat, spray coat, etc. can be used, and other methods are also possible, and detailed explanations of these can be found in "Coating Engineering" published by Nokin Shoten, pages 253-27.
It is described in detail on page 7 (published on March 20, 1972).

With this method, the magnetic layer coated on the support is guaranteed! After the treatment for orienting the magnetic powder in the layer is performed during or after applying the magnetic dispersion paint, the formed magnetic recording 1- is dried.

Further, if necessary, the magnetic recording medium according to the present invention is manufactured by subjecting it to surface smoothing processing or cutting it into a desired shape.

In this case, the orientation magnetic field is approximately 500~2,
000 Gauss, and the drying temperature is approximately 50-100℃
The drying temperature and drying time are about 3 to 1 minutes.

4. Orientation method for magnetic powder L1 in the patent publications and specifications of Shimoki. It has been stated.

For example, US TFIIN Permit No. 949,840, No. 2796.359, No. 3,001,891, No. 3172.776, No. 3,416,949,
Specifications of 3゜473.960, 3,681,138, Japanese Patent Publication No. 32-3427, 39-283
No. 68, No. 40-23624, No. 4Q-23625, No. 41-13181, No. 48-13043, No. 4
8-39722, etc.

The orientation direction of the magnetic material is determined by its use. That is, in the case of sound tapes, small video tapes, and memory tapes, it is parallel to the length of the tape, and in the case of broadcast video tapes, it is 30" to 90" in the longitudinal direction.
It is oriented with an inclination of .

The magnetic recording medium using the compound of the present invention has wear resistance,
It is a high quality magnetic recording medium with good storage stability and reproduction output with a high S/N ratio.

The present invention will be explained in more detail below using Examples.

The components, proportions, order of operations, etc. shown here can be changed as appropriate, and the present invention is not limited to the following examples. In addition, in the following examples, all "parts" refer to "July J1 Department".
shows.

Example 1 Exemplary compounds (1) to (4) of the present invention shown in No. 111 below were diluted with 500 s of methanol, and magnetic powder 10
0 part was added and mixed and dispersed. After filtering and air drying 8
Dry under reduced pressure at 0°C 12, treated magnetic powder 1 to 4 shown in Table 1
was created.

Table 1 A small amount of each of the above treated magnetic powders 8111 to 4 was collected,
When a flan aging test was conducted in a water-toluene system, the treated magnetic MI ore was completely formed into an organic layer. Since the untreated magnetic powder leaves a residual sound in the water layer, the treated magnetic powder modifies the surface of the Fi magnetic powder so that it can be well wetted into the solvent-based binder. I understand that.

Using the treated magnetic powder Nal~4 obtained above, a magnetic tape was produced with the following composition.

The above composition was placed in a ball mill, thoroughly heated and dispersed, and then a blackish brown magnetic powder dispersed paint was obtained. Apply this paint to one side of a 15μ polyethylene terephthalate film.
It was coated and dried to a dry film thickness of 6 μm while applying a Gaussian magnetic field.

The resulting wide magnetic wave was subjected to supercalender temperature sensing and slit into 127 pieces in width to obtain a video tape. The samples of the present invention are designated as Ugly 1 to Ugly 4, respectively.

Example 2 Exemplary compounds (1) to (4) of the present invention shown in Table 2 below were diluted in methanol SOO@, and a magnetic alloy (F
100 parts of e-Co-Ni) were added and mixed and dispersed.

Thereafter, it was filtered, air-dried, and then dried under reduced pressure to produce treated magnetic powders U5 to U8 shown in Table 2.

Table 2 Using the thus obtained treated magnetic powders ta5 to ta8, magnetic powder dispersed paints were prepared with the following compositions.

After the above composition was thoroughly mixed and dispersed in a ball mill, 3 parts of tolylene diisocyanate was added and mixed uniformly to obtain a magnetic paint. This paint was applied to one side of a 15 μm polyethylene terephthalate film 9 while applying a magnetic field of 1200 Gauss to a dry film thickness of 5 μm and dried.

The wide sample thus obtained was used as Example 10 Invention Sample N11.
Samples of the present invention N115-8 were prepared in the same manner as in Example 1.

Comparative Example 1 Untreated Co instead of surface-modified treated magnetic powder
Invention sample M of Example 1 except that Fe50<
A videotape was made in the same manner as al.

This is designated as comparative sample Nll.

Comparative Example 2 Example 2 except that an untreated magnetic alloy (F+-0o-Ni) was used instead of the surface-modified treated magnetic powder.
A videotape was prepared in the same manner as sample Na5 of the present invention. This is designated as comparative sample N1L2.

Comparative Example 3 After the above composition was thoroughly mixed and dispersed in a ball mill, a blackish brown magnetic powder dispersed paint was obtained. A videotape was obtained using this paint in the same manner as inventive sample NIL5 of Example 2. This j-p is designated as comparative sample m3.

Comparative Example 4 The above composition was thoroughly mixed and dispersed in a ball mill to obtain a magnetic powder-dispersed paint.

11 using this paint! A videotape was obtained in the same manner as sample part 5 of the invention fl12. This tape is designated as comparative sample Na4.

The comparative test results for each of these samples are summarized in Table 3K.

Note (a) RF output is measured using VT)l deck.
The RF' output at M was measured and expressed as a relative value with the output of the comparative sample Mal as 0.

(b) Abrasion resistance was determined by repeatedly sliding a 5 m long tape back and forth at a speed of 7 m/sec using a simulated head, and then visually measuring the tape surface and measuring 1 g #I.

(C) Storage stability was determined by the occurrence of sticking after being left to stand for 24 hours at a humidity of 80% and a temperature of 40°C.

From the above results, it can be seen that the magnetic recording medium according to the present invention is a high-density magnetic recording medium that has better wear resistance and storage stability and higher reproduction output than conventional ones.

Patent applicant Konishiroku Photo Industry Co., Ltd. Agent: Patent attorney Akira Sakaguchi (and 1 other person)

Claims (1)

[Scope of Claims] A magnetic recording medium characterized in that a magnetic recording layer on a support surface contains a compound represented by the following general formula [0]. General formula 0] 1o0 (RO)sr ON (R')a [In the formula, R represents a substituted or hydrogen-substituted furkyl group, fulkenyl group, or aryl group, and It' represents a hydrogen atom or a furkyl group, , four R' at four o'clock
is never a hydrogen atom. ]