JPH0123922B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a magnetic material and a method for manufacturing the same. Surfactants conventionally used to improve the dispersibility of powdered magnetic substances in the production of magnetic materials include fatty amine soaps, polyhydric alcohol fatty acid esters, polyoxyethylene alkyl ether phosphates, and polyoxyethylene. Alkyl phenyl ether phosphates and the like are known, and among them, specific polyoxyethylene alkyl phosphates and polyoxyethylene alkyl phenyl ether phosphates are known to be desirable. However, as the demand for improving the performance of magnetic materials has increased in recent years, there has been a strong desire to develop surfactants that are particularly suitable for this purpose. The present inventor has arrived at the present invention as a result of various studies in order to meet such demands, and the first aspect of the present invention is the general formula (However, R is an alkyl group, alkenyl group, or alkylphenyl group having 4 to 24 carbon atoms, n is 0 or an integer of 1 to 30, m is an integer of 1 to 30, [-
(C ₂ H ₄ O) _o (C ₃ H ₆ O) _n ]- The arrangement of C ₂ H ₄ O and C ₃ H ₆ O can be arbitrary. ) This is a magnetic material characterized by containing at least one of a phosphoric acid monoester compound, a phosphoric acid diester compound, and a derivative thereof as shown in the following. The second aspect of the present invention is the general formula (However, R is an alkyl group, alkenyl group, or alkylphenyl group having 4 to 24 carbon atoms, and n is 0 or 1
~30 integer, m is an integer from 1 to 30 [-
(C ₂ H ₄ O) _o (C ₃ H ₆ O) _n ]- The arrangement of C ₂ H ₄ O and C ₃ H ₆ O can be arbitrary. ) is a method for producing a magnetic material, which is characterized by immersing a powdered magnetic substance in an aqueous liquid of at least one kind of a phosphoric acid monoester compound, a phosphoric diester compound, and their derivatives shown in (a) and over-drying the powdered magnetic substance. . Furthermore, the third aspect of the present invention is the general formula (However, R is an alkyl group, alkenyl group, or alkylphenyl group having 4 to 24 carbon atoms, and n is 0 or 1 to
An integer of 30, m is an integer of 1 to 30 [-(C ₂ H ₄ O)
_o (C ₃ H ₆ O) _n ]- The arrangement of C ₂ H ₄ O and C ₃ H ₆ O can be arbitrary. This is a method for producing a magnetic material, which comprises blending at least one of the phosphoric acid monoester compound, phosphoric diester compound, and their derivatives shown in ) into a magnetic paint and processing the mixture. In the present invention, the term "magnetic material" refers to magnetic powder, magnetic paint, magnetic recording medium, and the like. The compound of the above general formula according to the present invention has 4 carbon atoms.
~24 alcohols or alkylphenols are subjected to addition polymerization of a specified propylene oxide, or ethylene oxide and propylene oxide by a known method, and the resulting compound is treated with a known phosphorylating agent such as phosphorus oxychloride or phosphorus pentoxide. The alcohols used as starting materials include butanol, octanol, decanol, lauryl alcohol, cetyl alcohol, stearyl alcohol, oleyl alcohol, and oxocarbons having 11 to 15 carbon atoms. Method-synthesized alcohols and other alkylphenols include octylphenol, nonylphenol, dodecylphenol, butylphenol, dinonylphenol, etc. However, from the viewpoint of effectiveness and economy, lauryl alcohol, stearyl alcohol, oleyl alcohol, carbon number 11, etc. ~15 oxo-synthesized alcohols, nonylphenol, etc. are preferred. (1) When only propylene oxide is added to these alcohols and alkylphenols, the average amount is 1 to 30 moles, preferably 3 to 10 moles on average.(2) When ethylene oxide and propylene oxide are added, the average amount is 1 to 30 moles each. Preferably ethylene oxide average 1~
The average amount of propylene oxide is 3 to 10 moles, and the addition order of ethylene oxide and propylene oxide may be either block or random. The phosphorylating agent may be either phosphorus oxychloride or phosphorus pentoxide, but in the case of adding only propylene oxide, phosphorus oxychloride is preferred. Usually, the phosphoric acid ester is obtained as a mixture of a phosphoric acid monoester and a phosphoric diester. Examples of derivatives of the compounds represented by the above general formula include alkali metal or alkaline earth metal salts, ammonium salts, amine salts, and the like. Powdered magnetic substances used in the production of the magnetic material of the present invention include γ-Fe ₂ O ₃ , magnetite (Fe ₃ O ₄ ), and bertolite iron oxide (FeOx1.33<
x<1.5), those modified with cobalt, manganese, nickel, zinc, chromium, etc., and powders of metallic iron and its alloys. They can be used alone or in appropriate combinations. To produce a magnetic material containing a compound (surfactant) represented by the above general formula in the method of the present invention: (1) An aqueous solution in which the surfactant is dissolved or suspended in water, or toluene, kerosene, or methyl ethyl ketone. (2) In the case of (1) above, a powdered magnetic substance is immersed in a non-aqueous liquid dissolved or suspended in an organic solvent such as chloroform, ethanol, or ethyl acetate, and a surfactant is adsorbed onto the particle surface of the magnetic powder. A method of spraying an aqueous or non-aqueous liquid onto a powdered magnetic material to adsorb a surfactant onto the particle surface of the powdered magnetic material. (3) When producing a magnetic paint by dispersing the powdered material in a resin binder. This can be done by adding a surfactant to the mixture. These methods of immersing a powdered magnetic material in an aqueous solution containing a medium surfactant are more preferable from the viewpoint of uniformly adsorbing the surfactant onto the particle surface of the powdered magnetic material and from the viewpoint of processing operation. It's a method. In the present invention, the amount of the surfactant according to the above general formula added is 0.1 to 6%, preferably 0.5 to 4%, based on the weight of the powdered magnetic material. If the amount added is too small than the above range, the desired effect cannot be obtained, and if it is too large, the strength of the magnetic coating film may be impaired, which is not preferable. Examples of the resin binder used in the present invention include vinyl, cellulose, urethane, epoxy, phenoxy, and acrylic resins. According to the present invention, as is clear from the Examples and Comparative Examples described later, various desirable effects are brought about compared to the case where conventional surfactants are used. In other words, (1) the compatibility of the powdered magnetic substance with the resin binder is improved and the dispersibility is improved;
The magnetic properties are improved. (2) The leaching of the surfactant on the surface of the magnetic coating film is suppressed and the abrasion resistance is improved by reducing stickiness. Also
The present invention is useful in two industries, such as (3) reducing foaming during immersion treatment in an aqueous system, and (4) uniform adsorption of surfactants and improvement of treatment efficiency. Next, examples of the present invention will be shown. Examples 1 to 3 (1) Surfactant according to the present invention A 5 mol of propylene oxide was added to 1 mol of stearyl alcohol, and then 5 mol of ethylene oxide was added to form poly(5) oxypropylene poly(5).
Oxyethylene stearyl ether is obtained. Furthermore, 0.4 mole of phosphorus pentoxide was reacted with 1 mole of the obtained poly(5) oxypropylene poly(5) oxyethylene stearyl ether, and the phosphoric acid monoester content was 65% and the phosphoric acid diester content was 31%.
An oily substance was obtained containing %. It is referred to as surfactant 1 according to the present invention. B. A mixture of 5 moles of ethylene oxide and 5 moles of propylene oxide is randomly added to 1 mole of stearyl alcohol, and then 0.8 mole of phosphorus oxychloride is reacted with 1 mole of the obtained adduct, followed by hydrolysis, washing with water, dehydration, and phosphoric acid monoester. minutes 71
%, and an oily substance containing 26% phosphodiester content was obtained. It is referred to as surfactant 2 according to the present invention. C Hydrolysis by adding 6 moles of propylene oxide to 1 mole of stearyl alcohol and reacting 0.9 moles of phosphorus oxychloride with 1 mole of the adduct obtained,
After washing with water and dehydrating, an oily substance containing 81% of phosphoric acid monoester and 14% of phosphoric acid diester was obtained.
It is referred to as surfactant 3 according to the present invention. (2) Comparative surfactant: 1 mole of stearyl alcohol and ethylene oxide
1 mole of the obtained adduct was reacted with 0.4 mole of phosphorus pentoxide to obtain a soft wax-like substance having a phosphoric acid monoester content of 64% and a phosphoric acid diester content of 33%. Comparative surfactant 1 is used. (3) Preparation of magnetic paint γ-Fe ₂ O ₃ powder...100 parts Vinyl chloride-vinyl acetate copolymer...15〃 Dioctyl phthalate...5〃 Surfactant of the present invention or comparative surfactant
...4〃 Toluene ...122〃 Methyl ethyl ketone ...110〃 The above mixture was sufficiently kneaded in a ball mill to obtain a magnetic paint. Parts indicate parts by weight. (4) Manufacture of magnetic recording medium The magnetic paint obtained in (3) was applied to a polyester film in a conventional manner, and then oriented and dried to obtain a magnetic recording medium in which a magnetic coating film with a thickness of about 8 μm was formed. (Examples 1 to 3 Comparative Example 1) (5) Characteristics of magnetic recording medium Comparison of Examples 1, 2, and 3 using surfactants 1, 2, and 3 according to the present invention and comparison using comparative surfactant 1 Regarding the magnetic recording medium of Example 1, coercive force Hc residual magnetic flux density Br, saturation magnetic flux density
Table 1 shows the measurement results of Bm, squareness ratio Br/Bm, and orientation ratio OR, and the sticky feel of the film after processing at 60° C. for 24 hours. Examples 1, 2 and 3 are compared to Comparative Example 1.
It can be seen that the dispersibility and filling properties are improved because Br, Bm, Br/Bm, and OR are improved. It can also be seen that the stickiness of the film has been improved.

[Table] Example 4 (1) Surfactant according to the present invention 6 moles of ethylene oxide are added to 1 mole of nonylphenol, then 3 moles of propylene oxide are added, and 0.5 moles of phosphorus pentoxide is added to 1 mole of the obtained adduct. were reacted to obtain an oily substance containing 5% phosphoric acid monoester and 27% phosphoric diester. It is referred to as surfactant 4 according to the present invention. (2) Comparative surfactant Add 6 moles of ethylene oxide to 1 mole of nonylphenol, react 1 mole of the resulting adduct with 0.5 mole of phosphorus pentoxide, and remove the phosphoric acid monoester component.
An oil containing 67% phosphoric acid diester content 25% was obtained. Comparative surfactant 2. (3) Treatment of powdered magnetic substance Add 2.5 g of Surfactant 4 according to the present invention or Comparative Surfactant 2 to a 500 c.c. beaker and add 300 c.c. of water.
was added and stirred for 5 minutes at 1000 rpm using a stirrer.
Immediately after the stirring was stopped, almost no foaming was observed in the case of Surfactant 4 according to the present invention, whereas foaming with a height of about 1 cm was observed in the case of the surfactant of Comparative Example 2. Next, 100 parts by weight of r-Fe ₂ O ₃ powder was added to this aqueous solution and stirred for 5 minutes using a stirrer, but in the case of surfactant 4 according to the present invention, no foaming occurred at all, whereas in the case of surfactant 4 of comparative example 2, no foaming occurred. A foaming phenomenon was observed in the agent. Next, the filtrate obtained by filtration was dried at 80° C. for 24 hours to obtain a magnetic powder for magnetic recording media. (4) Preparation of magnetic paint r-Fe ₂ O ₃ powder treated with surfactant 4 according to the present invention or comparative surfactant 2...103 parts by weight Vinyl chloride-vinyl acetate copolymer...15 Dioctyl phthalate...5 Toluene ...122 〃 Methyl ethyl ketone ...110 〃 The above mixture was sufficiently kneaded in a ball mill to obtain a magnetic paint. (5) Production of magnetic recording medium The magnetic paint obtained in (4) was applied to a polyester film in a conventional manner, oriented, and dried to obtain a magnetic recording medium in which a magnetic coating film with a thickness of about 8 μm was formed.
(Example 4, Comparative Example 2) (6) Characteristics of magnetic recording medium The characteristics of Example 4 and Comparative Example 2 are shown in Table 2, and Example 4 has superior characteristics compared to Comparative Example 2. have.

[Table] Example 5 Magnetic properties, etc. were measured in the same manner as in Example 3 except that the r-Fe ₂ O ₃ powder was replaced with cobalt-modified r-Fe ₂ O ₃ powder, and the following results were obtained. I got it.

[Table] Example 6 Magnetic properties, etc. were measured in the same manner as in Example 4, except that xylene was used instead of water and the material was dried at 60°C for 24 hours after treatment.The following results were obtained. Obtained.

[Table] Example 7 Magnetic properties, etc. were measured in the same manner as in Example 4, except that the preparation of the magnetic paint in Example 4 was changed as shown below.ゞEquivalent results were obtained. r-Fe ₂ O ₃ powder treated with surfactant 4 according to the present invention...100 parts by weight Vinyl chloride-vinyl acetate copolymer...17.5 Polyurethane resin...7.5 Methyl ethyl ketone...100 Cyclohexanone...100

Claims (1)

[Claims] 1. General formula (However, R is an alkyl group, alkenyl group, or alkylphenyl group having 4 to 24 carbon atoms, n is 0 or an integer of 1 to 30, m is an integer of 1 to 30, [-
(C ₂ H ₄ O) _o (C ₃ H ₆ O) _n ] - The arrangement of C ₂ H ₄ O and C ₃ H ₆ O can be arbitrary), A magnetic material comprising at least one acid diester compound and a derivative thereof. 2 General formula (However, R is an alkyl group, alkenyl group, or alkylphenyl group having 4 to 24 carbon atoms, n is 0 or an integer of 1 to 30, m is an integer of 1 to 30, [-
(C ₂ H ₄ O) _o (C ₃ H ₆ O) _n ]- The arrangement of C ₂ H ₄ O and C ₃ H ₆ O can be arbitrary. ) A method for producing a magnetic material, which comprises immersing a powdered magnetic substance in at least one kind of aqueous solution of a phosphoric acid monoester compound, a phosphoric diester compound, and their derivatives shown in (), filtering, and drying the powdered magnetic material. . 3 General formula (However, R is an alkyl group, alkenyl group, or alkylphenyl group having 4 to 24 carbon atoms, n is 0 or an integer of 1 to 30, m is an integer of 1 to 30, [-
(C ₂ H ₄ O) _o (C ₃ H ₆ O) _n ]- The arrangement of C ₂ H ₄ O and C ₃ H ₆ O can be arbitrary. 1.) A method for producing a magnetic material, which comprises blending at least one of a phosphoric acid monoester compound, a phosphoric diester compound, and a derivative thereof shown in () into a magnetic paint and processing the mixture.