JPS5931002A - Preparation of surface-treated ferromagnetic powder and magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve dispersibility by a method wherein ferromagnetic powder is dispersed in an electrolytic solution which is then treated by such a solution that a surface active agent with charges opposite to those of the ferromagnetic powder is mixed to a hydrophilic solvent, and a hydrophobic organic solvent is added thereto to move the ferromagnetic powder into the organic layer. CONSTITUTION:First, ferromagnetic powder is dispersed in an electrolytic solution such as NaOH or KOH, and the surface of the powder is charged to be positive or negative depending on the type of the electrolyte. Next, this electrolyte solution is treated by such a solution that a cationic or anionic surface active agent with charges opposite to surface charges of the ferromagnetic powder is mixed to a hydrophilic solution. A hydrophobic organic solvent such as aliphatic hydrocarbon or alicyclic hydrocarbon is added to the treated solution, thereby moving the ferromagnetic powder into the organic layer. As a result, it becomes possible to obtain surface-treated ferromagnetic powder with sufficient hydrophobic property and a dispersion solution thereof.

Description

[Detailed description of the invention]

The present invention relates to a dispersion of surface-treated ferromagnetic powder, a method for producing the powder, and a magnetic recording medium, and particularly relates to a dispersion of surface-treated ferromagnetic powder suitable for high-density recording and production of shadow powder. Conventionally, magnetic recording media such as recording tapes and video tapes are mixed with binders such as vinyl copolymers, cellulose resins, epoxy resins, and polyurethane resins. However, the use of these binders alone or in combination tends to impair the dispersibility of ferromagnetic powders, resulting in poor surface properties and wear resistance of conventional magnetic recording media. Particularly in video tapes that require short wavelength recording, poor dispersion of ferromagnetic powder in the magnetic layer leads to deterioration of the S/N ratio and decrease in sensitivity. In addition, since the magnetic coating comes into contact with the magnetic field (7) during recording and reproduction, repeated use causes wear and tear, and the ferromagnetic powder contained in the coating is likely to fall off, causing clogging of the magnetic head. This led to undesirable results. For this reason, various additives are used for the purpose of improving the dispersibility of the strong B powder and improving the abrasion resistance. For example, Japanese Patent Publications No. 41-18064, No. 43-186, No. 43-669°, No. 47-15624, No. 49-F13402, No. 49-Fi8B04, No. 4
No. 9-84405, No. 51-40904, No. 52-7
As described in each publication of No. 0811, higher fatty acids, fatty acid amides, fatty acid esters, higher alcohols, metal salts, sulfuric esters of higher alcohols, and polyethylene are added to the magnetic paint containing ferromagnetic powder and binder. A magnetic recording medium is produced by coating a magnetic coating material containing oxide, lecithin, etc. on a non-magnetic support. However, it has been difficult to produce a magnetic recording medium with desirable characteristics even if these additives are simply added during the production of magnetic paint. For example, if large amounts of these additives are used, the mechanical strength of the magnetic layer will be reduced, which is an undesirable result. Unfortunately, after the magnetic property is formed, a so-called "blooming" phenomenon occurs in which the additive gradually oozes out, resulting in unfavorable results in terms of storage stability. In addition, the magnetic properties of amphoteric (fli) and the dispersibility of strong (e) powder were also improved for the purpose of improving the dispersibility of strong (e) powder.
As described in the specification of No. 8, it has been proposed to pre-treat the ferromagnetic powder with a surfactant for surface treatment. A hydrophilic surfactant such as lecithin is added to the solvent to prepare an active agent bath solution, and after adding and dispersing the ferromagnetic powder to be treated in the solution, it is filtered and air-dried. The surface-treated ferromagnetic powder is obtained by drying under reduced pressure.This method definitely causes 1-Pluming.
Although this phenomenon can be suppressed, there is a problem in that the dispersibility of the ferromagnetic powder becomes worse. Furthermore, there is a problem in that a satisfactory dispersion state cannot be achieved by simply dipping the ferromagnetic powder into a surfactant bath and dispersing it, as has been done in the past. An object of the present invention is to provide a novel surface-treated ferromagnetic powder dispersion, a novel surface-treated ferromagnetic powder manufacturing method, and a novel magnetic recording medium that overcome the above-mentioned drawbacks. That is, the objects of the present invention are as follows. The first object of the present invention is to provide a well-dispersed dispersion of surface-treated ferromagnetic powder. A second object of the present invention is to provide a method for producing surface-treated ferromagnetic powder with excellent dispersibility. A third object of the invention is to provide a magnetic recording medium with good wear resistance. A fourth object of the present invention is to provide a magnetic recording medium with good storage stability. A fifth object of the present invention is to provide a magnetic recording medium with a good S/N ratio. A sixth object of the present invention is to provide a magnetic recording medium with high reproduction output. Among the above-mentioned objectives of the present invention, the first objective is to disperse ferromagnetic powder in an electrolyte bath, and then treat it with a hydrophilic solvent mixed with a surfactant with a charge opposite to that of the powder surface. This is achieved by a dispersion of surface-treated ferromagnetic powder, which is characterized in that a hydrophobic organic solvent is added to the above-mentioned treatment agent to transfer the ferromagnetic powder to an organic layer. Among the above aspects of the present invention, the second objective is the cold resistance of the electrolyte. i Disperse the magnetic powder, then treat it with a hydrophilic solvent mixed with a surfactant with a charge opposite to that of the powder surface, add a hydrophobic organic solvent to the previous treatment, and then disperse the ferromagnetic powder. This is achieved by a method for producing surface-treated ferromagnetic powder, which is characterized by transferring the powder to an organic layer and then taking it out. *Among the chain objectives of the invention, the third to sixth objectives are Ili! in an electrolyte bath solution! i Disperse the magnetic powder [2, then mix the surface active agent on the surface of the shadow powder with a hydrophilic solvent, and add the hydrophobic organic solution H to the processing box to form a ferromagnetic powder. A magnetic recording medium characterized in that it contains a surface-treated ferromagnetic powder that transfers the powder into several layers and extracts the carbon.
In addition, ferromagnetic powder is dispersed in an electrolyte bath solution, and then treated with a mixture of a hydrophilic solvent and a surfactant with an electric potential opposite to that of the powder surface. A magnetic recording medium characterized in that a binder is added to a surface-treated ferromagnetic powder obtained by adding a magnetic organic solvent and transferring the ferromagnetic powder to an organic solvent, and the mixture is coated on a non-magnetic support. achieved by
J1. Ru. The electrolytes according to the present invention include those that charge the surface of ferromagnetic powder rice negatively and those that charge the surface of ferromagnetic rice powder negatively. J6,
Na(,)H, KOH, Na, PO,, Na, P
2O,,Na,P,0,2. Na25in, , Na4Sin4. Na2WO,
,K,PO,,K,P2O7゜K,P,0,2. K2
SiO3, K4SiO, K2WO, etc. are used to positively charge the ferromagnetic powder Table 111, and 17 is Al.
0I? l, Feeko, , 'ri+]14, etc. are excited. 9 times and 1 times of melt t of the pre-electrolyte, electric p
Types of Ir and Ir to use! It varies depending on the isoelectric point of the magnetic powder, but in order to charge the surface of the ferromagnetic powder with +E and K, the concentration of the electrolyte solution is such that i(1, In order to make the surface of the ferromagnetic powder negative, use an electrolyte solution with a concentration such that TJ)I is lower than the isoelectric point of the ferromagnetic powder. do. In addition, for the ferromagnetic powder 1009r, the electrolyte bath 3N Ip, 2(l
ml-50 (using 10me, good? L < IB
, 50mg to 2000] Ni Ina. In the present invention, as a dispersion method for dispersing ferromagnetic powder in an electrolyte bath, a ball mill, a sand grinder,
Examples include a method using a Qi% impeller dispersion rock, a high-speed mixer, a homogenizer, and the like. It is believed that by dispersing the ferromagnetic powder in an electrolyte solution, shear force acts effectively on the aggregated powder, thereby reducing the proportion of the aggregated ferromagnetic powder. Although water alone is often sufficient as a solvent for the electrolyte solution according to the present invention, various hydrophilic solvents may be used as necessary, such as linear or branched alcohols or alcohol ethers having 1 to 8 carbon atoms. Or alcohol such as polyhydric alcohol (methanol, ethanol, ethoxyethanol, ethylene glycol, etc.):
Ketones having 3 to 6 carbon atoms (e.g. acetone,
Methyl ethyl ketone, etc.): hydrophilic ethers such as tetrahydrofuran or dioxane, nitrogen-containing hydrophilic heating media such as dimethylpyrrolidone, dimethylformamide, dimethylacetamide, pyridine, etc., per 100 parts by weight of water, good. 6. Any of the above can be used as the electrolyte according to the present invention, but if the ferromagnetic powder is a metal, if the surface of the powder is positively charged, rust may easily occur. 0, it is preferable to charge the powder negatively, and when the ferromagnetic powder is a metal compound, the surface of the powder may be charged positively or negatively. In the present invention, the ferromagnetic powder is dispersed in a solution and the ferromagnetic powder is treated with an interfacial oily agent with a charge opposite to that of the ferromagnetic powder surface. If an electrolyte is used that first makes the ferromagnetic powder surface m1 negative, a surfactant with an opposite charge, that is, a cationic surfactant, is used to first positively charge the ferromagnetic powder surface. When an electrolyte is used, an anionic surfactant is used. In addition to being dispersed in an electrolyte bath solution, the ferromagnetic powder, whose surface is charged, is treated with a surfactant of opposite charge. It is thought that a stable adsorption layer of surfactant will be formed on the surface of the ferromagnetic powder.In the case of 17, a treatment different from the treatment according to the present invention, that is, a strong magnetic powder with a negatively charged surface is applied. When magnetic powder was treated with a 7-ion surfactant, or when a ferromagnetic powder whose surface was positively charged was treated with a cationic surfactant, the surface quality obtained was inferior. Examples of cationic surfactants that can be used include quaternary ammonium salts, ammonium salts of higher alkyl amines, pyridine, other chamber-containing heterocyclic compounds, and their ammonium salts, phosphonium salts, and sulfonium salts. Tani glaze surfactants are mentioned.Anionic surfactants include sodium stearate,
Carboxylic acid salts of sodium palmitate, sodium oleate, potassium laurate; sodium cetyloxyacetate, p-tucylphenoxy^'' carboxylic acid group that forms a needle bond such as acid I, lium, etc.; dodecyl sulfone Carboxylic acid salts rich in amide bonds such as sodium amide acetate and potassium cetyl sulfonamide acetate; Carboxylic acid salts that cure the amine group of sulfur-lium lauryl aminoacetate and decylaminopropion M%; monoester dodecyl alcohol phthalate ) l) Nonorubonic acids that remove ester bonds such as lamb salt; fatty alcohol sulfate esters such as stearyl sodium sulfate and ammonium lauryl alcohol sulfate; sodium lauryl polyethylene glycol ether sulfate;
Polyethylene glycol ether sulfate such as sodium p-octylphenylpolyethylene glycol ether sulfate; sodium stearamide ethanol sulfate 1 p-
Sulfuric esters with amide bonds such as off-glubenzamide ethanol sodium sulfate; sulfuric esters with ester bonds such as butyl sodium sulfooleate; sulfonic acids such as sodium cetyl sulfonate and sodium p-decylbenzene sulfonate Layer: β-hydroxydodecylsulfuric acid sulfonate having a hydroxyl group such as 1M sodium phosphate; sulfonate salt having an ester bond such as α-sulfostearate isopropyl ester sodium ester, sulfosuccinate bis-2-ethylhexyl ester sodium chloride, etc. (fi j basin; sulfonate salts having an amide bond such as α-sulfolauric acid butyramide sodium salt; sulfonic acid groups having an ano group such as α-sodium cyanocetylsulfonate; N-tetratecyltaurine sodium salt, etc. Sulfonates with amine groups; Sulfonates with ether bonds such as β-dodecyloxyethylsulfonic acid; Sulfonic acid groups with nosulfide bonds such as sodium lauryl thiomethane sulfonate; Dotesyl alcohol phosphate monoester disodium salts, phosphoric acid ester salts such as decyl alcohol phosphoric acid diester monosodium salt, etc. The surfactant according to the present invention can be used in an amount of 1 part by weight to 50 parts by weight per 10,000 weight of ferromagnetic powder. In particular, it is preferable to use 0.11 to 10 parts by weight. Less than 0.05 parts by weight is enough for one effect, and if it exceeds 50 parts by weight, emulsification tends to occur, so it is preferable. This is because the above-mentioned surfactant solution can be mixed with only water, or a hydrophilic solvent as mentioned in the explanation of the above-mentioned electrolyte solution (when used for a surfactant, a hydrophilic solvent is used) (A surfactant may be dissolved in the surfactant.) Alternatively, the surfactant may be mixed with a medium prepared by mixing water and the above-mentioned hydrophilic solvent in any proportion. When the surfactant according to the invention is used as a solution of the hydrophilic solvent and/or water, it is preferable to use the surfactant as a solution.Therefore, for example, ferromagnetic powder 10,000
When you want to use 5 parts by weight of surfactant,
The concentration of the surfactant is 10% by weight (
50 parts by weight of the hydrophilic solvent-1: or a mixture of 9 parts of water and 10 parts by weight of a surfactant. It is okay to use some parts. In addition, a mixture of ferromagnetic powder 1009rK and 1 surfactant in 4W aqueous solvent was used at 20m/~5+
Use 100 ml [7, preferably 50 nDj ~ 2
00 (l ml used. Ferromagnetic powder, surfactant, hydrophilic organic solvent lσ/l
'! It can be used in various proportions. +As the surfactant according to the invention, any of the above surfactants can be used, but cationic thread surfactants are more preferred than anionic surfactants. This is because, as mentioned above, the electrolyte according to the present invention and 1
This corresponds to No. 7 in which the surface of the ferromagnetic powder is preferably negatively charged. In the present invention, a highly stable powder is dispersed in an electrolyte bath oil, and then treated with a hydrophilic solvent mixed with a surfactant having an opposite charge to the surface of the ferromagnetic powder, and then treated with the treatment liquid. A hydrophobic organic solvent is added to the mixture to transfer the ferromagnetic powder to the organic layer. The hydrophobic organic solvent is a linear or branched aliphatic hydrocarbon having 5 to 14 carbon atoms, an alicyclic hydrocarbon having 5 to 11 carbon atoms, a substituted (preferred substituent) having 6 to 18 carbon atoms, is a halogen or alkyl group) or an unsubstituted aromatic hydrocarbon, a cyclic or acyclic ketone having 4 to 10 carbon atoms, or a halogen atom with 1 to 1 carbon atoms. However, examples include halogen-containing aliphatic hydrocarbons, and those with a solubility parameter (generally called SP value) of 7.0 or more and less than 10.0 (value at 5°C) are preferred. Among the hydrophobic organic solvents, the aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, and halogenated aliphatic hydrocarbons are preferable from the viewpoint of operability and ease of separation from water. More preferred are aliphatic hydrocarbons, alicyclic hydrocarbons, and aromatic hydrocarbons. Examples of the preferred hydrophobic organic solvents include pentane, hexane, hebutane,
Examples include octane (all of the above may be linear or branched), cyclopentane, cyclohegizane, cyclohebutane, cyclooctane, benzene, toluene, xylene, carbon tetrachloride, chloroform, methylene chloride, and the like. A mixture of one or two or more highly hydrophobic organic solvents may be used. The use of hydrophobic organic solvents varies depending on the solvent, but strong IB powder 100.9
5000 mA from almA for r, M'! It is particularly desirable to use it within the range of 50 ml to 2000 mA. By adding a hydrophobic organic solvent, the treatment liquid is roughly divided into 21 layers: an organic layer (a liquid layer with strong hydrophobicity) and an aqueous layer (a liquid layer with a strong hydrophilicity). The surface-treated ferromagnetic powder migrates to the organic layer, and those that have not been sufficiently hydrophobized are left behind in the water layer. Therefore, the dispersion of the surface-treated ferromagnetic powder according to the present invention obtained by removing the water layer , the surface-treated ferromagnetic powder that had been sufficiently hydrophobized was selectively included, and therefore a well-dispersed dispersion of the surface-treated ferromagnetic powder was obtained. Further, by removing the solvent from the dispersion according to the invention and drying it, the surface-treated ferromagnetic powder according to the invention can be obtained, and the obtained powder can be obtained as described above in 41: Dispersion teaching according to the invention. As the sufficiently hydrophobized powder was selectively extracted, it was a surface-treated ferromagnetic powder with reduced dispersibility. Regarding the excellent dispersibility of the surface-treated ferromagnetic powder obtained by the dispersion 7α of the surface-treated ferromagnetic powder according to the present invention or the above-mentioned production method according to the present invention, see 1tm [plJ
As will be explained in detail below, as one example, the sedimentation rate of ferromagnetic powder in 0, n-hexane can be used as a guide. The excellent dispersibility of the surface-treated ferromagnetic powder obtained by grinding the surface-treated ferromagnetic powder resulted in a magnetic coating material with extremely good dispersibility in magnetic coatings used for making magnetic recording media, which will be described later. Its excellent dispersibility can be widely used in the fields of magnetic fluids and magnetic pigments. Ferromagnetic powder 19r was added to a sedimentation tube with an inner diameter of 10 M and an inner volume of 30 tn/:, and after shaking thoroughly for 1 minute, the suspended n-
The height to the interface with hexane is defined as the sedimentation rate, m (24
per hour), and the sedimentation rate is 0 to
100, preferably 0 to 106, gives good dispersibility! i! It can be said to be an iei powder. Another example is that the sedimentation rate is considered to be a measure of the degree of aggregation (the lower the value, the lower the rate of aggregation), whereas the surface of the ferromagnetic powder is considered to be hydrophobic. To find out whether the powder is floating or slightly dispersed, suspend and disperse the powder in various solutions with known surface tension (e.g. water-methanol mixed solvent). The degree of hydrophobicity of the powder is determined by the surface tension of the melt when I can think. The dispersion of the surface-treated ferromagnetic powder according to the present invention or the surface-treated ferromagnetic powder produced by the above-mentioned production method 1 has extremely excellent dispersibility, whether evaluated by the above-mentioned sedimentation rate or hydrophobicity. Ta. In the present invention, after dispersing ferromagnetic powder in an electrolyte solution,
The ferromagnetic powder may be treated with the above-mentioned surfactant solution without engineering the R-type powder, and the ferromagnetic powder may be taken out from the above-mentioned treatment solution and treated with water and/or an ice-based aqueous solvent,
A hydrophobic organic solvent may be added to transfer the ferromagnetic powder to the first layer. The surface-treated ferromagnetic powder obtained by the production method of the present invention is mixed and dispersed in a solvent together with a binder to obtain a magnetic paint, and the paint is coated on a non-magnetic support to form a magnetic layer. Such a magnetic recording medium is produced. Further, the dispersion of the surface-treated ferromagnetic powder according to the present invention is concentrated and dried as necessary, and a binder is added, kneaded, and dispersed to obtain a magnetic paint, and the paint is coated on a non-41B support. , a magnetic layer, and one magnetic recording medium according to the present invention is manufactured. In any of the above magnetic paints, a dispersant,
It may also contain additives such as lubricants, antistatic agents, and antistatic agents. Regarding the manufacturing method of mother paint, Japanese Patent Publication No. 3F1-15, No. 39-26794, No. 43-186, No. 47-28
No. 043, No. 47-28045, No. 47-28046
No. 47-28048, No. 47-31445, No. 48-11i62-#, No. 48-21331 Sword, No. 48
-33683, West German Published Patent Publication No. 2060655
It is described in detail in various publications such as USSR Patent Specification No. 308033. Binders that can be used in the magnetic layer of the magnetic recording medium according to the present invention include conventionally known thermoplastic resins, thermosetting resins,
Reactive resin "!", electron beam curable side fat, or mixtures thereof are used. As the heat 0Tffi resin, the softening temperature is 150°C or less, and the average molecular weight is 10.0 (10 to 200, 000,
About 200 to 2,000 fake products, such as vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, acrylic ester-acrylic acid 17 o = To I
J.A. Copolymer, acrylic acid ester-vinylidene chloride copolymer, acrylic acid ester-styrene 7 co-M combination, methacrylic acid ester-acrylonitrile copolymer, methacrylic acid ester-vinylidene chloride copolymer (4), methacrylic ester- Styrene copolymer, urethane elastomer, polyvinyl fluoride, vinyliso/-acrylonitrile chloride copolymer, acrylonitrile-butadiene copolymer, polyamide resin, polyvinyl butyral, cellulose m4
(cellulose acetate butyrate, cellulose diacetate, cellulose triacetate, cellulose flobioide, nitrocellulose, etc.), styrene-butadiene copolymer, polyester resin, chlorovinyl ether-acrylic acid ester copolymer, amine resin , various synthetic rubber-based thermoplastic resins, and mixtures thereof. These and these resin wires, Special Publication No. 37-6877, No. 39-
No. 12528, No. 39-19282, No. 40-5:1
No. 49, No. 40-20907, No. 41-9463,
No. 41-14059, No. 41-16985, No. 42
-6428, No. 42-11621, No. 43-462
No. 3, No. 43-15206, No. 44-2889, No. 44-17947, No. 44-18232, No. 45-
No. 14020, No. 4F+-14500, No. 47-18
F173, No. 47-22063, No. 47-2206
No. 4, No. 47-22068, No. 47-22069,
No. 47-22070, No. 48-27886, U.S. Patent No. 3,144,352, No. 3,419,42
No. 0, No. 3,499,789, No. 3,713,8
It is described in the specification of No. 87. The thermosetting resin or reactive resin has a molecular weight of 200,000 or less in the state of coating oil, and after coating and drying, the molecule tLL becomes infinite due to reactions such as b condensation and addition. Among these resins, those which do not soften or melt before the resin is thermally decomposed are preferred. Specifically, examples include phenol 84 B'R, epoxy resin, polyurethane curable resin, urea resin, melan resin,
Alkyd resin, silicone resin, acrylic reactive resin,
Mixtures of polymeric polyester resins and isocyanate prepolymers, mixtures of methacrylate copolymers and diisocyanate prepolymers, mixtures of polyester polyols and polyisocyanates, urea formaldehyde resins, low molecular weight glycols/^molecular weight diols/ Mixtures of triphenylmethane triisocyanate, polyamine resins, mixtures thereof, etc. These resins are disclosed in Japanese Patent Publications Nos. 39-8103 and 40-97.
79@, No. 41-7192, No. 41-8016, No. 41-14275, No. 42-18179, No. 43-
No. 12081, No. 44-28 (No. 123, No. 45-14
No. 501, No. 4Fi-24902, No. 46-1310
No. 3, No. 47-22067, No. 47-22072,
No. 47-22073, No. 47-28045, No. 47
-28048, U.S. Patent No. 47-28922, U.S. Patent No. 3,144゜353, U.S. Pat.
No. 0, No. 3, 437. No. 510, same No. 3. F) No. 97,273, No. 3,78
No. 1°210 and No. 3,781,211. Examples of electron-side irradiation-curable resins include unsaturated prepolymers,
Typical maleic anhydride type, urethane acrylic type, epoxy acrylic type, polyester acrylic type, polyether acrylic type, polyurethane acrylic type, polyurethane acrylic type, or as a multifunctional seven-piece, ether acrylic type, urethane acrylic Types include epoxy acrylic type, phosphate ester acrylic type, aryl type, / vine hydrocarbon type, etc. 1. These binders may be used alone or in combination, and other additives may be added as necessary. is added. The mixing ratio of the surface-treated ferromagnetic powder and the binder according to the present invention is 10 to 10 parts of the binder to 100 parts of the ferromagnetic powder.
It is used in an amount of 400 parts by weight, preferably in the range of 30 to 200 ifi parts. If the amount of binder is too large, the recording density of the magnetic recording medium will be reduced, and if it is too small, the strength of the magnetic layer will be poor, resulting in undesirable situations such as decreased durability and powder falling off. Furthermore, in order to improve the durability of the magnetic recording medium according to the present invention, the magnetic layer can contain various curing agents,
For example, polyincyanate can be included. As polyisocyanates, diisocyanates and 31
There are adducts with curved polyols, pentamers of diisocyanates, and decarboxylation compounds of 1.3 mol of diisocyanate and water. Examples of these include an adduct of 13 moles of tolylene diisocyanate and 1 mole of trimethylolpropane, an adduct of 3 moles of metaxylylene diisocyanate and 1 mole of trimethylolpropane, a pentamer of tolylene diisocyanate,
There are 5iii:II consisting of 3 moles of tolylene diisocyanate and 2 moles of hexamethylene diisocyanate, and a decarboxylated product obtained by reacting 3 moles of hexamethylene diisocyanate with 1 mole of water, and these are easily obtained industrially. In addition to the surface-treated ferromagnetic powder according to the present invention, the binder and curing agent described above, the magnetic layer contains additives such as a dispersant, a lubricant,
Abrasives, antistatic agents, etc. may also be added. Dispersants used include caprylic acid, capric acid,
Fatty acids having 8 to 18 carbon atoms such as lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, elaidic acid, linoleic acid, lyuronic acid, etc. (R-0C) Represented by OH, where R is 7 carbon atoms ~17 saturated or unsaturated alkyl groups): alkali metal (lii
, Na, K, etc.) or alkaline earth metals (Mg,
Metal soap consisting of Ca, Ba, etc.); lecithin, etc. are used. I F calligraphy needle---0 filling fi=-E-
1lij two power 1- conversion 1 eye bush-blooded tiger quarrel haiku le ni yotsuji 4
In addition to these, higher alcohols having 12 or more carbon atoms and sulfuric esters may also be used. Further, the surfactants described in the dispersion of the surface-treated ferromagnetic powder or the method for producing the surface-treated ferromagnetic powder according to the present invention can also be used. These dispersants may be used alone or in combination with 2a or more. These dispersants are added in an amount of 1 to 20 parts by weight per 100 M parts of the binder. These dispersants are described in Japanese Patent Publication No. 39-28369, No. 44
-17945, 48-IF)001, U.S. Patent No. 3. F187,993, same No. 3,470,021
It is written in the #IB book etc. As a lubricant, silicone oil, carbon black,
Graphite, carbon bra, 7 graphite polymer,
Molybdenum disulfide, tungsten disulfide, 1 carbon atom
Fatty acid esters (so-called waxes) consisting of 2 to 16 monobasic fatty acids and monohydric alcohols having a total number of carbon atoms of 21 to 23 carbon atoms can also be used. These lubricants are added in an amount of 0.2 to 20 parts by weight based on 100 parts of the binder phase. Regarding these, Q Kotesha Special Publication No. 43-23889, No. 43-8
Publications such as 1Fi43, U.S. Patent No. 3,470,021
Published, No. 3,492.23 F1, No. 3, 497
, No. 411, No. 3,523,086, No. 3.62
fi, 76 ('l, No. 3, 6: (No. 0, 772, No. 3.6: (No. 4,253, No. 3,642, 53)
9 bow, specifications of the same No. 3,687,725, IBMT
electrical disclosure Bul, 1
etin Vol, 9, A 7゜Page 77
9 (December 1966): ELEKTRONIK1
961 Bian 12, page 380, etc. Commonly used abrasive materials include fused alumina, silicon carbide chromium oxide, corundum, artificial corantum, diamond, artificial diamond, sacrostone, and emery (main ingredients: corundum and magnetite). These σ) abrasives have an average particle size of 0.05 to 5μ
The thickness of the rust is also σ) force (used, particularly preferably 0.
It is 1 to 2μ. These abrasives are added in an amount of 7 to 21 parts by weight per 100 parts by weight of the binder. These techniques are described in Japanese Patent Publication No. 115510/1986, U.S. Patent No. 3,007,807, and U.S. Patent No. 3,041,1.
No. 96, No. 3,687,725, British Patent No. 1,1
No. 45,349, West German Patent (DT-PS) 853
, No. 211. The antistatic agents used include conductive powders such as graphite, carbon black, and carbon black graft polymers; natural surfactants such as saponin; and nonionic surfactants such as alkylene oxides, glycerinone threads, and glycidols. Agents: A-class alkylamines, quaternary ammonium salts, pyridine, other heterocycles,
Cationic surfactants such as phosphonium or sulfonium; anionic surfactants containing acidic groups such as carboxylic acid, sulfonic acid, phosphoric acid, sulfuric acid ester groups, and phosphoric acid ester groups; diamino acids, aminosulfonic acids, and sulfuric or phosphoric acid of amino alcohols. Ampholytic activators such as esters are used. These surfactants that can be used as anti-teishin agents are disclosed in U.S. Pat. 2.71', No. 623, No. 9, No. 1, No. 2
, 240,472, 2,288,226, 2,676.122, 2,676.924, 2,676.97Fi, 2,691,566 , No. 2,727,860, No. 2,730,498
No. 2,742,379, No. 2,739,89
No. 1, No. 3,068,101, No. 3,158,4
No. 84, No. 3,201.2F) No. 3, No. 3,210 of the same house
, No. 191, No. 3,294,540, No. 3,41
Fi, No. 649, No. 3,441,413, No. 3,
No. 442,654, No. 3,475,174, No. 3
, 54fi, No. 974, West German Patent Publication (OL8
) 1,942,665, British Patent No. 1.07731
No. 7, No. 1,198,450, etc., Ryohan Odara and others [Synthesis of surfactants and their applications] (Maki Shoten 1964 edition): A. W. Peiri [Surface Active Agents J (Interscience Publications Inc. 1958 Edition) 2T,
"Encyclopedia of Surfactant Agents Volume 2" by P. Sisley (Chemical Vapri, Shcompany 1964 edition): [Surfactant 9
J! 6th printing (Zagyozu 1 Company name)” 1941
(February or Sunday) etc. Further, the surfactants described in the dispersion of the optical surface-treated ferromagnetic powder or the method for producing the surface-treated ferromagnetic powder according to the present invention can also be used. These surface oil agents can be used alone or in combination.

[You may add... Although these are used as antistatic agents, they are sometimes used for other purposes, such as dispersion, improving magnetic properties, improving lubricity, and as coating aids. (Solvents for B-type paints or solvents used when applying magnetic paints include: acetone, methyl ethyl ketone, methyl isobutyl ketone, ketones such as cyclohexanone; alcohols such as methanol, ethanol, gropal, phthanol; 4: vinegar [Ester threads of ethyl, ethyl acetate, butyl acetate, ethyl lactate, glycol acetate monoethyl ether; glycol ether threads such as diethyl ether, glycol dimethyl ether, glycol monoethyl ether, dioxane; benzene, toluene, xylene, etc. Aromatic hydrocarbons: methylene chloride, ethylene chloride, carbon tetrachloride, chloroform, ethylene chlorohydrin, dichlorobenzene, etc. Rokenized hydrocarbons can be used. Twisted, non-abrasive support material Examples include polyesters such as polyethylene terephthalate-1 and polyethylene-2,6-naphthalate, polyolefins such as polypropylene, cellulose derivatives such as cellulose triacetate and cellulose diacetate, 7'-last ink such as polycarbonate, Ou. Approximately 5 to 50μ
m, and in the case of tisuf, card-like, 30, am
-10 mm, 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-68-sex support group may be provided with a so-called backoat, which is the opposite of the first rule in which a cap is provided for the purpose of preventing static electricity, preventing transfer, etc. Regarding barak coats, see, for example, U.S. Pat.
．． 4, No. 401, No. 3,293,066, No. 3
, No. 617, No. 378, No. 3,062,676,
Same No. 3.734,772, same y* 3,476.59
No. 6, No. 2,643,048, No. 2,803,5
56'@, No. 2.887,462, No. 2, 92
3, 642 +4F, same No. 2.997,451, same No. 3, OO7, 892, same No.: U, 04], 19
No. 6, No. 3,115,420'@, No. 3, i66.
It is described in each specification such as No. 688. In addition, the form of the support is tape, sheet, card, de, f.
It may be made of either a disk or a drum, and the material of the yuzu is selected depending on the form and necessity. A dispersion of light surface-treated ferromagnetic powder or surface-treated ferromagnetic powder according to the invention, a binder, a dispersant, a lubricant, an abrasive agent, an anti-weighing agent, a magnetic paint, etc. It is said that Before mixing and dispersing the ferromagnetic powder or optically treated ferromagnetic powder, all of the above components should be added at the same time.
Rirui is individually mixed #1! There is a method of making magnetic obstetrics by adding each ingredient to the machine and continuing kneading. Various types of kneading rocks are used for mixing and dispersing. Examples are two roll mill, three roll mill, whole mill, pebble mill, sand grinder, Szegvari
There are attritor, high speed impeller Mm, Akane speed stone mill, high speed impact mill, dispernitter, island speed mixer, homogenizer, ultrasonic generator 11, etc. When the magnetic paint according to the invention is separated by these methods, it is dispersed very well, and when the dispersibility evaluation method described in Section 0 is used, the number of aggregates when observed with an electron microscope is was significantly less than that of conventional magnetic paints. Technologies related to crosstalk dispersion include T, c, and PATTON.
AuthorPa1nt FLOW and Pigment
Dispersj, on (1964 John Wi
(Published by Lley & 5pns). Also, U.S. I±1 Patent No. 2,581,414 and U.S. I±1 Patent No. 21
85J] No. 56. Coating methods for coating the magnetic paint onto the support to form a magnetic layer include air doctor coating, blade coating, air knife coating, squeeze coating, impregnation coating, reverse roll coating, transfer roll coating, and gravure coating. , kiss coat, cast coat, spray coat, etc. can be used, and other methods are also possible. (Issuance) is described in detail. The magnetic layer coated on the support by such a method is optionally treated to orient the ferromagnetic powder according to the present invention in the layer, and then the formed magnetic layer is dried. The magnetic recording material of 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 5o in alternating current or direct current. ~3500 Gauss, and the drying temperature is approximately 1) ~]
It is preferable that the IK is about 00'C and the drying time is about 3 to 10 minutes. The method for orienting the ferromagnetic powder according to the present invention may be the method described in the following patents. For example, U.S. Patent No. 1,949,840;
No. 796,359, 143. o 01, No. 891, No. 3.172.776, No. 3,416,94
No. 9, No. 3, 473, 960, No. 3,681
, No. 138, Tokusho No. 2-3427, No. 39-28368, No. 40-23624, No. 40-
No. 23625, No. 41-13181, No. 48-130
No. 43 and No. 48-39722. The direction of orientation of the ferromagnetic powder according to the present invention is determined by its use, i.e., parallel to the length of the tape in the case of sound tapes, small video tapes, and memory tapes; In some cases, it is oriented at an inclination of 130° to 9u' with respect to the long awn direction. The high-speed recording medium f4- produced by I/C as described above and according to the present invention has extremely good abrasion resistance and excellent storage stability compared to conventional ones. . 1
7. Magnetic recording medium t4--1 according to the present invention, S/N ratio (
The signal-to-noise ratio) has been significantly improved compared to conventional recording media, and the playback output has also been improved.
It was possible to obtain higher playback output than the conventional one. From the above seven points, the magnetic recording medium according to the present invention showed excellent performance even in density recording. The present invention will be explained in more detail below using examples. Those skilled in the art will readily understand that the ingredients, proportions, order of operations, etc. shown herein may be changed without departing from the spirit of the present invention. Therefore, the invention should not be limited to the examples below. In addition, in the following examples, "1 part" refers to "Tozaibu", and the term "1 audio tape" used in Example 1 and "video tape" 1 in this specification
It is synonymous with "magnetic recording medium". Examples 1 to 12 100 parts of the ferromagnetic powder shown in Table 1 below was mixed with about 1
In addition to 1000 parts of a specified electrolyte aqueous solution, the mixture was dispersed using a sand grinder. Table 1 Among the ferromagnetic powders listed in Table 1 obtained in this way, in the electrolyte water bath report 1 containing ferromagnetic powders with a positive surface charge, sodium dotecyl sulfate, an anionic surfactant, was used. [50 parts of a 0% aqueous solution was added, and in A2, a 10% aqueous quasi-silicon of sodium oleate, which is also an anionic surfactant, was added, and after each was mixed and dispersed again, a hydrophobic organic solvent was added and the mixture was redispersed. After that, the aqueous layer was removed and the organic layer was taken out, and the resulting dispersion was filtered once, air-dried, and then dried under reduced pressure to form a surface-treated ferromagnetic powder plate.
Obtained Bian 2. In addition, among the ferromagnetic powders listed in Table 1, military # quality water bath 9ya 3 and A5 containing ferromagnetic powder with a negatively charged surface charge were used.
In , the cationic surfactant N-cetyl-N
-Add 50 parts of a lO% aqueous solution of ethylmorphorinium ethosulfate, and for A4 and Flat 6, add 150 parts of a 10% aqueous solution of decyltributylammonium bromide, which is also a cationic surfactant, and mix and disperse again. , add a hydrophobic organic solvent, disperse again 39- 7 / Kotoshi, remove the aqueous layer 7 and take out the old layer L 7 The resulting dispersion is filtered once, air-dried, and then dried under reduced pressure 1- , surface-treated ferromagnetic powders &3~ya6 were obtained. In addition, among the ferromagnetic powders in Table 1, in the electrolyte aqueous solution containing ferromagnetic powder whose surface is positively charged, 10% of sodium dodecyl sulfate (1/1/2 of methanol and water) was used.
Add 950 parts of the mixed solvent of 1) bath, and add 5 parts of 10% methanol solution of sodium oleate to the plate 2.
Add 0 parts, mix and disperse again (7), add a hydrophobic organic solvent, disperse again, remove the aqueous layer and mix (17).
The dispersion obtained by taking out several layers was filtered for 1-1 hours, air-dried, and then dried under reduced pressure to obtain a surface-treated ferromagnetic powder plate.7. I got A8. In addition, among the highly resistant powders listed in Table 1, N-cetyl and N-ethylmorpholinium ethosulfate are used in electrolyte water-soluble standards &3 and Notification 5 containing ferromagnetic powders with negatively charged surface charges. 10% methanol bath @5o parts of IJ butylammonium bromide (decyl for A4 and A6)
-4()- respectively, after mixing and dispersing again, adding a hydrophobic organic solvent and dispersing again, removing the aqueous layer and taking out the organic layer, and filtering the resulting dispersion. After natural drying, it was dried under reduced pressure to obtain surface-treated magnetic powders A9 to AI2. (However, for Al1, a solvent solution containing % methanol and water was used.) Surface-treated ferromagnetic powder 711i obtained as above
1 to AI2 are shown in Table 2 below. Comparative example l Pure water 1 (in 100 parts, 00 containing *yeso + powder 10
After dispersing 0 parts of dotesil (#t, sodium acid lO
Add 50m of % water dispersion and disperse the angle, then disperse the enemy by 1
After filtration and air drying, the powder was dried under reduced pressure to obtain a surface-treated ferromagnetic powder. This is referred to as comparative surface-treated ferromagnetic powder sample 1. (In this comparison column, the sample was simply dispersed in pure water without being dispersed in electrolyte water mm.) Comparative Example 2 In a toluene bath Wklo 00 parts containing 5 parts of lecithin (a commonly used dispersant) , CO-containing B″e30
4 After 100 parts of powdered wood and 100 parts of powdered food, it was filtered once, air-dried, and dried under reduced pressure to obtain a surface-treated ferromagnetic powder. This is referred to as comparative surface-treated ferromagnetic powder sample 2. Comparative Example 3 When 100 parts of Fe powder was dispersed in 1000 parts of toluene solution containing 5 parts of lecithin (a dispersing agent commonly used in the past), the result was σ4, natural drying edge, vacuum drying and coating (... treatment). A ferromagnetic powder was obtained.This is referred to as comparative surface-treated ferromagnetic powder sample 3. Comparison of the untreated Qo 4,5 untreated ferromagnetic powder Sample 3 Differences in the ferromagnetic powder samples compared to P″ee powder after treatment were compared using the degree of hydrophobicity and sedimentation rate. Add each ferromagnetic powder to a liquid, and if the ferromagnetic powder floats in the solution without dripping, the surface tension (eL) of the solution
It shows that the surface energy (d, ynθ/t=m) of the ferromagnetic powder is smaller than the ferromagnetic powder (d, ynθ/t=m), and the strong S powder is dispersed or precipitated by the dispersion of the ferromagnetic powder. It can be judged from the fact that the surface energy of the ferromagnetic powder is larger than the tension in Table 1 of the solution. The sedimentation speed is determined by adding 1g of magnetic powder to a sedimentation tube (inner volume: 30m13
, inner diameter: l1IN), add n-hexane and
1 ml, shake all individual powder dispersions at the same rate for 1 minute, let stand, and after 24 hours, measure the stability of the suspension field from the supporting surface, and calculate the sedimentation rate. I asked for it. Table F shows the measurement results of the degree of hydrophobicity and sedimentation rate of sea urchin. From the above results, the surface-treated ferromagnetic powder according to the present invention,
hydrophobic (″
It can be seen that it has excellent dispersibility under conditions (a) oily. Next, using the thus obtained surface-treated ferromagnetic powder,
The following magnetic paint was produced. Thereafter, 1.3 parts of tolylene diisocyanate was added and mixed uniformly to obtain a magnetic paint. This paint was applied to one side of a polyethylene terephthalate film with a film thickness of 1 fi/jm while applying a restraining force to a dry film thickness of 5 μm.
It was coated to give a thickness of m. The 1-wide sample thus obtained was supercalendered to 12.7vrta +4j
A videotape was obtained by slitting the tape so that the voltage was Vc. Among the video tapes produced, those using the surface-treated tough powders of Examples 1 to 12 were manufactured by magnetic tape sample shops 1 to 12.
The tapes made of Jang 4B1 fresh vJ powder in Comparative Examples 1 to 5 are referred to as Comparative Tape Samples A1 to 5. Comparative test feeds for these videotapes are summarized at $-4. Note that Br/Bm represents the squareness ratio, which is 1
The larger the 11i, the better the magnetic properties. a) RF! 4 MH using a VTR keyboard for output measurement
The RF output at No. 2 was measured and expressed as a relative value with the output of Comparative Tape Sample-4 set at 0. b) For the S/N ratio, for the sample tape using CO-containing Fθ304 as the ferromagnetic powder, the value of Comparative Example 4 was Q d,
Regarding the sample tape designated as B and using Fe as the ferromagnetic powder, the value of Comparative Example 5 was expressed as a relative value of □dB. Note that the material used is metal (FiF in this example or comparative example).
Items in e) are marked with an American mark. C) Abrasion resistance was measured by repeatedly sliding a 5 m long tape back and forth at a speed of 7 m/8 eC using a simulated head, and then measuring the tape surface visually and using a microscope. d) Adhesiveness was determined by the occurrence of sticking after standing for a period of time at a humidity of 80% and a temperature of 40°C. From the above results, the magnetic recording medium according to the present invention has better wear resistance and storage stability than conventional ones (for example, no sticking due to adhesiveness), and has excellent S/N. It was found that the magnetic recording medium has a high reproduction output and is suitable for high-density recording. Examples 1 to 12 are about video tapes, but when used as audio tapes, they have good abrasion resistance and storage stability, as well as excellent S/N ratios and high playback output. It was a magnetic recording medium suitable for high-density recording. Examples The magnetic paints used in creating the magnetic recording media according to the present invention in Examples 1 to 12 and the comparative magnetic paints used in creating the samples in Comparative Examples 1 to 5 were applied with an applicator, respectively. When applied on a glass plate to a thickness of 60 microns (at the time of infiltration), the degree of dispersion was observed using a microscope.
The comparative magnetic paint had a lot of aggregates, whereas the magnetic paint used to create the samples of Examples 1 to 12 was uniformly dispersed and had very few aggregates. . Examples 14 to 25 Among the ferromagnetic powders listed in Table 1, 1! contains ferromagnetic powders whose surface is positively charged. j'l! Dodecyl sulfate, which is an anionic surfactant, is used in the aqueous solution 1).
Add IJum's 10% water bath solution Kanto, and in step 2, add 50 parts of 10% water bath solution of sodium oleate, which is also an anionic yarn surfactant 1 bioactive agent, and mix and disperse again, and then add 100 parts of ferromagnetic powder. Hydrophobic to <hm
After adding 1000 parts of medium and dispersing again, the water layer was removed and the surface-treated ferromagnetic powder was dispersed on the dispersion side 14. Obtained 15 pieces. In addition, among the ferromagnetic powders listed in Table 1, Table 3
In 5, N-cetyl-N-ethylmorphorinium ethosulfate, a cationic non-surfactant, was used.
Add 50 parts of 0% water solution to each, and add 10% water solution of decyltributylammonium bromide, which is also a cationic surfactant, to A4 and &6, mix and disperse again, and then add 100 parts of ferromagnetic powder. After adding 1,000 parts of a hydrophobic organic compound* to the mixture and dispersing it again, the aqueous layer was removed to obtain a dispersion of surface-treated ferromagnetic powder. -50- In addition, among the strong ferromagnetic ladle in Table 1, in Amanelyte aqueous solution store 1 containing ferromagnetic powder whose surface is positively charged, 10% methanol solution of sodium dodecyl sulfate 5O In addition, in flat 2, 50 parts of 1O% methanol m# of sodium oleate were processed, mixed and dispersed at different angles, and then 1000 parts of hydrophobic organic #g medium was added to 100 parts of ferromagnetic powder. , after redispersing and tc, water j- is removed,
A flat plate 21 was obtained by dispersing the surface-treated ferromagnetic powder. In addition, among the ferromagnetic powders described in Cloth-1, an electrolyte aqueous solution containing a ferromagnetic powder whose surface is negatively charged @, A 3
10% methanol/150% of N-cetyl and N-ethylmorpholinium ethocarphate were added in Steps 4 and 6, respectively. IO% methanol solution of tesyltributylammonium bromide 5
After adding 0 parts to each and mixing and dispersing each again, 1000 parts of a hydrophobic organic medium was added to 100 parts of the ferromagnetic powder, and the mixture was dispersed again. After fc, the water layer was removed to form a dispersion of surface-treated ferromagnetic powder. J#0.22 to A25 were obtained. The dispersion rows 14 to 5 of the surface-treated ferromagnetic powder obtained as described above are shown in Table 5 below. -Dmu - Comparative Example 6 In 1000 parts of pure water, CO-containing Fθ304 powder 1()0
10% aqueous solution of sodium dodecyl sulfate was added and dispersed again, 1000 parts of cyclohexane was added to 100 parts of ferromagnetic powder, dispersed again, the water layer was removed, and the surface treatment was strengthened. A dispersion of magnetic powder was obtained. This was designated as sample 6 of a comparative surface-treated ferromagnetic powder dispersion. (In this comparative example, it was not dispersed in an electrolyte aqueous solution, but simply dispersed in pure water.) Comparative Example 7 In 5 tooo parts of toluene containing 5 parts of lecithin (a conventionally commonly used dispersant), CO containing Fθ30
After dispersing 100 parts of Powder No. 4, the water layer was removed to obtain a dispersion of surface-treated ferromagnetic powder. This was designated as sample 7 of a comparative surface-treated ferromagnetic powder dispersion. Comparative Example 8 After dispersing 100 parts of Fe powder in 1000's of toluene solution containing 5 parts of lecithin (a commonly used dispersant), the water layer was removed to obtain a dispersion of surface-treated ferromagnetic powder. Ta. This is designated as Sample 8 of polarized polarization of comparative surface-treated ferromagnetic powder. Comparative Example 9.10 Untreated 00-containing 1'''304 powder was dispersed in 1000 parts of methyl isobutyl ketone to determine the π phase.Comparative ferromagnetic powder dispersion sample 9. 100 parts of untreated Fe powder was dispersed in methyl isobutyl ketone. Differences in dispersibility were compared based on sedimentation rate.The sedimentation rate was determined for each sample dispersed in the sedimentation tube as described above: 3
Shake the ferromagnetic powder dispersion liquid (2ml) and Togane's ferromagnetic powder in the same manner for 1 minute, let it stand, and measure the height from the solution surface to the suspension interface after the cooling time. The sedimentation velocity was determined.Table 6 in F shows the measurement results of the degree of hydrophobicity and the sedimentation velocity.Table 6 From the above results, it can be seen that the dispersion of the surface-treated ferromagnetic powder according to the present invention M1. hydrophobic compared to powder dispersions (
It can be seen that uniform dispersion is achieved under lipophilic conditions. Next, the dispersion of the surface-treated ferromagnetic powder thus obtained was concentrated and dehydrated using a molecular sieve, and the molecular sieve was removed. After adjusting the solvent by concentrating or adding the solvent so that it has the same proportion as the base manure, polyurethane, silicone oil, and partially hydrolyzed vinyl chloride-vinyl acetate copolymer were added like the base manure to create a magnetic paint. 1 5 parts of cyclo-xane The above composition was placed in a ball mill, thoroughly mixed and dispersed, and then 3 parts of tolylene diisocyanate was added and mixed uniformly to obtain a magnetic paint. A magnetic field was applied to one side of a polyethylene terephthalate film with a film thickness of 15 pm, and a dry film thickness of 5 μm was applied to this paint.
It was coated to give a thickness of m. The wide sample thus obtained was slit into supercalender treated L, 12.7 wt1] to obtain a videotape. Among the video tapes produced, those prepared by dispersing the surface-treated ferromagnetic powder of Examples 14 to 5 were magnetic tape sample A.
14 to 2!5, and those obtained by dispersing the ferromagnetic powder of Comparative Examples 6 to 1o are referred to as comparative tape samples A6 to 1O. The comparative test results of these videotapes are summarized in Table 7. Note that Br/Bm represents the squareness ratio, and the larger the value, the better the magnetic properties. -) b - From the above results, the magnetic recording medium according to the present invention has better abrasion resistance and storage stability (for example, no sticking due to adhesiveness, etc.), and the magnetic recording medium according to the present invention has better wear resistance and storage stability than conventional ones. It was found that this magnetic recording medium is suitable for high-density recording, has excellent /N and high reproduction output. Examples 14 to 25 are about video tapes, but when used as audio tapes, they have good abrasion resistance and storage stability as well as a good S/N ratio and high playback output. It was a magnetic recording medium suitable for high-density recording. Example 26 The tc magnetic paint used in creating the magnetic recording media according to the present invention in Examples 14 to 25 and the comparative magnetic paint used in creating the samples in Comparative Examples 6 to IO were applied to each other. Using a magnetic paint, it was applied to a glass plate with a thickness of 60 microns (when wet), and the degree of dispersion was observed using WJ4 microscopic paint. The magnetic paints used in preparing the samples of Examples 14 to 25 were uniformly dispersed and had very few aggregates. Agent: Yo G Yoshi Beautiful Procedural Amendment August 301, 1981 Patent J 'H Kazuo Wakasugi 1, 1 Title of Invention Method for producing surface-treated ferromagnetic powder and magnetic recording medium 3
If amended, the relationship with tenancy Patent applicant address: Nishi-Shinjuku, Shinjuku-ku, Tokyo], 26, 2, 1 River Name (+27) Roku Konishi Photography Co., Ltd. 4 Agent: 19] Residence: Hino, Tokyo 5, Konishi Roku Photo Gyokugyo Co., Ltd., 1 Sakura-cho, Ichi. Date of the amendment order. 6. The column "Number of inventions stated in the claims" of the application to be amended.
Contents of amendments to the “Claims” column of the specification and the “Detailed Description of the Invention” column 7 of the specification (a) “Number of inventions stated in the claims” is corrected as follows. do. (Incorrect) 4 → (Correct) 3 (B) “Claim 11fi, I will be corrected as shown in the attached sheet. (C) The “Detailed Description of the Invention” column will be corrected as shown below. (1) On page 5, line 17, "Dispersion of surface-treated ferromagnetic powder and novel surface treatment strength" is corrected to "surface treatment strength." (2) Delete the first and second lines of page 6. (3)-(7) Correct as shown below. False Correct Page 6, line 3; 2nd purpose → same as 1st purpose Line 5; purpose of @3 → same as 2nd purpose Line 7; 4th purpose →
3rd purpose 2- Isadome same line 9; 5th purpose → 4th purpose same line 11; 6th purpose → 5th purpose (8) Page 6, lines 13- Delete the 19th line. (9)-00) Correct as shown below. Rivets, page 6, additional line; 2nd purpose → 1st purpose, page 7, line 7: 3rd to 6th purpose (11), page 7, line 12 ``Contains surface-treated ferromagnetic powder...''
...Contains surface-treated ferromagnetic powder in a magnetic layer on a non-magnetic support...'' is corrected. (1. Correct "... after dispersing, sparse" in the 7th line of page 39 to "... after dispersing, sparse per 100 parts of ferromagnetic powder". (133, page 39) Line 8: “...add an organic solvent,
" was corrected to "...add 1000 parts of organic solvent." (1st line, page 39, line 7, ``After combining and dispersing, add a hydrophobic 3- organic solvent...'') After dispersing the residue, ferromagnetic powder,
Add 1000 parts of a hydrophobic organic solvent to 444100 parts...'' is corrected. (15) On page 40, line 10, "After dispersing, add a hydrophobic organic solvent" to "After dispersing, add 1000 parts of a hydrophobic organic solvent to 100 parts of ferromagnetic powder." correct. (10, page 41, line 1, ``...after dispersing, add a hydrophobic organic solvent'' to ``...after dispersing, add t of hydrophobic organic solvent to 100 parts of ferromagnetic powder. (17) On page 55, line 15, change ``The degree of hydrophobicity and sedimentation rate to Table 6 below...'' to ``The sedimentation rate to Table 6 below...''. 4- Attached claims (υ Ferromagnetic powder is dispersed in an electrolyte solution, and then treated with a solution containing a hydrophilic solvent mixed with a surfactant with a charge opposite to that of the surface of the powder. A method for producing a surface-treated ferromagnetic powder, characterized in that a hydrophobic organic solvent is added to the treatment liquid, and the ferromagnetic powder is transferred to an organic layer and taken out. Next, the powder was treated with a solution in which a surfactant with a charge opposite to that of the surface of the powder was mixed with a hydrophilic solvent, a hydrophobic organic solvent was added to the treatment solution, and the ferromagnetic powder was transferred to the organic layer and taken out. A magnetic recording medium characterized by containing surface-treated ferromagnetic powder in a magnetic layer on a non-magnetic support. (3) Ferromagnetic powder is dispersed in an IE electrolyte solution, and then a charge opposite to that of the powder surface is applied. A surface-treated ferromagnetic powder is bonded to a dispersion of surface-treated ferromagnetic powder obtained by treating the surfactant with a solution mixed with a hydrophilic solvent, adding a hydrophobic organic solvent to the treatment solution, and transferring the ferromagnetic powder to the organic layer. A magnetic recording medium characterized in that it is coated on a non-magnetic support by adding an agent.1 Procedural amendment September 7, 1982 2 Name of +111 3 Relationship with the case of the person making the amendment Address of the patent applicant 1-26-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Name (127) Konishiroku Photo Industry Co., Ltd. 191 Address 5 Konishiroku Photo Industry Co., Ltd., 1 Sakura-cho, Hino-shi, Tokyo Date of amendment order 6. Column 7 of “Detailed Description of the Invention” of the specification to be amended, Contents of the amendment (a) Correct the “Detailed Description of the Invention” column as below T
Ru. (1) Page 10, line 10 [... may be negatively charged. ” may be made to have a negative band S. Examples of ferromagnetic powders that can be used in the magnetic layer of the magnetic recording medium according to the present invention include r -Fe20B powder, Fe a
O4 powder, co containing r -Fe103 powder, c C:o, containing 2- Procedural amendment Kazuo Wakasugi, Commissioner of the Japan Patent Office] Indication of fact A 1 Patent application No. 141282 Ji32 Name of the invention Surface-treated ferromagnetic powder Manufacturing method and magnetic recording medium 3
Relationship with the case of the person making the amendment Patent Applicant Address No. 26, Nishi-Shinjuku, Shinjuku-ku, Tokyo 2nd Publication Name (+27) Konishiroku Photo Industry Co., Ltd. Representative Director Nobuhiko Kawamoto 4 Agent Address 191 Address 1-5 Sakura-cho, Hino-shi, Tokyo Date of the order for amendment 6. Column 7 for "Detailed description of the invention" in the specification subject to amendment Contents of the amendment Correct it accordingly. (1) 7 to 20 for [...] in the 5th line from the top of the fourth row
J is corrected as "...1 to 20 J for K." (2) The fourth line from the top of page 32 is corrected as "diethyl ether, glycol dimethyl ether, J is rf recall dimethyl ether." (3) On the 9th line from the top of page 32, “ethylene chlorohydrin, dichlorobenzene, etc.” is corrected to “dichlorobenzene, etc.” (4) 2nd line from the bottom of the audience page to 4th line from the top of page 37
According to the present invention... is oriented. ” to be deleted. 2- Procedural amendment 1, indication of the case Patent application No. 141282 +j2 Title of the invention Method for manufacturing surface-treated ferromagnetic powder and magnetic recording medium 3 Relationship with the amendment case Patent applicant address Shinjuku, Tokyo Ward Nishi-Shinjuku 1-26-2M Name (127) Roku Konishi Photo 2 [Representative Director of Industry Co., Ltd. 1]
Nobuhiko Kawamoto 4 Agent 191 Address Tokyo 1 No. 111 Sakura-cho 1-5 Date of amendment order 6 Voluntary application 6 Column 7 of Detailed Description of the Invention J of the specification to be amended, Amendment The content of "Detailed Description of the Invention" is corrected as follows. 1.Page 6, line 10, "Preferably 30~..."
is corrected to "preferably 10~...". 2- Procedural Amendment 1 Neutral σ) p 4.
j2 Name of the invention Method for producing surface-treated ferromagnetic powder and magnetic recording medium 3
Relationship with the Nagisa incident, which is supplemented by 11 Patent applicant address: Nishi-Shinjuku, Shinjo-ku, Tokyo] J'1126 No. 2 Name (+27) Roku Konishi ■ j' Shin Kogyo Co., Ltd. Kandai Roku Director Nobuhiko Moto 4 Agent address: 191, Tokyo 11! l'f width Sakura 1 town 1 suit land Konishi Roku Photography Ryo Co., Ltd. 5 Sodeyama 11th anniversary of the β order] Spontaneous 6, "Detailed description of the invention" column 7 of the specification to be amended, of the amendment The content column “Detailed Description of the Invention” is corrected as follows. (1) Delete "the dispersion liquid and the powder" from the 12th and 13th lines of page 2 of the specification $. (2) Delete page 15, line 9 to line 14 of the specification. (3) The phrase “dispersion liquid or the above according to the present invention” from lines 5 to 6 on page 18 of the specification is deleted. (4) "Inner volume 30d" on page 18, line 17 of the specification is corrected to "for 30 ml." (5) "Excluding water layer" on page 1, line 17 and line 19 of the specification is deleted. 2-

Claims (1)

[Claims] (1) Ferromagnetic powder is dispersed in an electrolyte solution, and then treated with a solution containing a hydrophilic solvent mixed with a surfactant with a charge opposite to that of the surface of the powder, and the treatment solution is Add a hydrophobic organic solvent,
A dispersion of surface-treated ferromagnetic powder, characterized in that ferromagnetic powder is transferred to organic 1m. +21 Ferromagnetic powder is dispersed in an electrolyte solution, and then treated with a solution in which a hydrophilic solvent is mixed with a surfactant with an opposite charge to the surface of the powder, and a hydrophobic organic solvent is added to the treatment solution,
A method for producing surface-treated ferromagnetic powder, characterized by transferring ferromagnetic powder to an organic layer and then taking it out. (3) Ferromagnetic powder is dispersed in an electrolyte solution, then treated with a solution containing a hydrophilic solvent mixed with a surfactant with a charge opposite to that of the powder surface, and a hydrophobic organic solvent is added to the treated image. , magnetic recording 1131 characterized by containing surface-treated ferromagnetic powder taken out by transferring ferromagnetic powder to an organic layer.
t. (4) During the electrolytic JjiL bath, ferromagnetic powder is dispersed, and then a surfactant with an opposite charge to the surface of the powder is mixed in a hydrophilic solvent [-treated with saliva, and then treated with Sr' prior to Sr' treatment. Add a hydrophobic organic solvent to transfer the ferromagnetic powder to the organic layer; add a binder to the resulting dispersion of the surface-treated ferromagnetic powder, and add a non-magnetic support A magnetic recording medium (book) characterized by