JP3362789B2 - Magnetic recording media - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium comprising a support and a magnetic paint applied on the support. The present invention relates to a magnetic recording medium containing abrasive particles in the magnetic layer. Thus, head adhesion is reduced, and running properties and tape properties such as stills are improved. 2. Description of the Related Art In magnetic recording media such as audio, video, floppy disks, computer tapes, etc., in order to prevent a magnetic layer from being damaged by contact with a magnetic head, aluminum is used.
₂ O ₃ , Cr ₂ O ₃ , TiO ₂ , SiO ₂ , SiC, α-Fe
It is common practice to add non-magnetic inorganic materials such as ₂ O ₃ and ZnO ₂ . However, if the type, particle size, and amount of the inorganic material particles to be added are not properly selected, problems such as damaging the magnetic head, increasing the wear amount of the magnetic head, and deteriorating the electromagnetic conversion characteristics occur. For this reason, conventionally, the above-mentioned inorganic materials have been used alone.
Alternatively, a small amount is added in combination to strengthen the magnetic layer.
The inventor has previously added particles containing two types of inorganic materials as an inorganic material as a coating film reinforcing agent,
Research has been conducted to provide a magnetic recording medium that enhances the effect of reinforcing the coating film, has less head adhesion, and has less head wear. Until now, coatings have been reinforced by mixing non-hard inorganic powders with high hardness.In recent years, however, with the improvement in performance required for video tapes and tapes for digital equipment, the use of fine magnetic powders and high dispersion bonding Agent (binder)
The adoption of tapes and the smoothing of the tape surface have progressed, and these measures are disadvantageous to the durability of the magnetic coating, the stability of friction, and the adhesion of the head, and further enhance the durability of the coating. ,
It is desired to improve the head cleaning effect. The use of inorganic material particles that have been generally used in the past for such high-performance tapes deteriorates the electromagnetic conversion characteristics and causes inadequate reinforcement, resulting in tape damage during durability running and head cleaning effects. Deficiency causes problems such as an increase in head adhesion and a decrease in output.
In addition, running failure may occur due to an increase in friction. [0004] Therefore, the present inventors thought that the problem associated with high performance can be solved by appropriately selecting the inorganic material and the amount of addition as a coating film reinforcing agent. .
The present applicant has proposed that TiO ₂ and α-Al ₂ O ₃ as inorganic materials,
It has been found that the combined use of other inorganic particles can satisfy the conflicting requirements of damage to the magnetic head, reduction in wear, and reduction in wear of the magnetic tape. However, head wear and friction stability were not sufficient. SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic recording medium with reduced head adhesion, reduced head wear, and improved physical properties. [0006] When α-Al ₂ O _3, which is generally used at present, is used alone, the reinforcing effect of the magnetic coating film and the decrease in head adhesion are difficult. Further, a similar problem occurred with a combination of two or more kinds of inorganic particles. However, α-
Compound having Fe element at the time of production of Al ₂ O ₃ or Si element
And a compound having an Fe element as α-Al
Reducing head mutually compensate for each other's shortcomings attachment, head wear, the wear of the magnetic layer by using the alpha-Al ₂ O ₃ containing were mixed with ₂ O ₃ raw material calcined to Si or Fe, or both I was able to. According to the present invention, the average particle size is 0.10 μm to 0.30 μm.
In μ , 0.5 to 3.0% of Fe element or 0.05 to 0.
A magnetic paint in which α-Al ₂ O ₃ containing 30% of Si element and 0.5 to 3.0% of Fe element is dispersed in a binder together with a magnetic powder or the like is applied to a non-magnetic support. Magnetic recording medium. [0008] Here, the average particle size of 0.10μ ~ 0.30μ
Fe, or a method of manufacturing the α-Al ₂ O ₃ containing Si and Fe elements, in manufacturing the α-Al ₂ O ₃ by firing a raw material, a compound having a Si or Fe element before firing Mix and fire to obtain Fe or α containing Si and Fe elements
-Al ₂ O ₃ . Si addition amount is 0.05
The content of Fe is preferably 0.5 to 3.0%. In this document,% means% by weight. When the particle diameter is less than 0.10 μm, the effect of reinforcing the magnetic coating film is insufficient, and when it exceeds 0.30 μm, the surface properties of the magnetic coating film are deteriorated, and the electromagnetic characteristics are adversely affected. If the content of Si and Fe is less than the lower limit, the reinforcing effect is insufficient,
Even if the upper limit is exceeded, the reinforcing effect is insufficient. Examples of the binder for the magnetic layer that can be used in the present invention include a polyurethane resin, a thermosetting resin such as vinyl chloride-vinyl acetate-vinyl alcohol copolymer, and an acrylic acid having a double bond sensitive to an electron beam. A well-known resin such as an electron beam curable resin can be used. In particular, thermosetting resins and electron beam curable resins are suitable. As the magnetic powder that can be used in the present invention, a conventionally known magnetic powder for a magnetic recording medium can be used. The magnetic paint of the present invention has a binder other than the above abrasive,
It is manufactured by adding and mixing a well-known magnetic powder, a solvent, and a lubricant, and one of the methods well-known in the art can be adopted as the method. As the lubricant that can be used in the magnetic paint of the present invention, any conventionally known lubricants such as fatty acids such as myristic acid and stearic acid, and fatty acid esters such as butyl stearate and butyl myristate can be used. In addition, other inorganic reinforcing agents may be contained in a very small amount. The average particle size added to the magnetic paint is 0.10 μm
The amount of α-Al ₂ O ₃ containing 0.30 μm of Si or Fe element can be added at a ratio of 0.5 to 15.0% by weight based on the binder resin. If the amount is too large, the dispersibility is adversely affected, and the electromagnetic characteristics are deteriorated. If the amount is too small, there is no effect. As the non-magnetic support that can be used in the present invention, there can be used synthetic resins such as polyester and other non-magnetic supports conventionally used for magnetic recording media such as audio, video, floppy disk, and computer tape. it can. DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference Example 1 A magnetic paint having the following composition was prepared and dried to a thickness of 3
It was applied to a polyester base having a thickness of 14 μm to a thickness of 14 μm, calendered, heat-treated, and then cut to a width of イ ン チ inch. 100 parts of magnetic powder (BET 45 m ² / g Co-γ-Fe ₂ O ₃ ) 20 parts of binder polyvinyl chloride copolymer (VAGH) / polyurethane resin (N-2304) 20 parts Abrasive (Si element 0.1. 10% content α-Al ₂ O ₃ particle size 0.11μ) 10 parts ・ MEK 300 parts ・ Carbon 3 parts ・ Additives (fatty acids) 2 parts Reference Example 2 The particle size of the abrasive is 0.22μ A magnetic tape was manufactured in the same manner as in Reference Example 1 except that the magnetic tape was changed. Reference Example 3 A magnetic tape was manufactured in the same manner as in Reference Example 1, except that the particle size of the abrasive was changed to 0.28 μm. Example 1 An abrasive was prepared by using an α-particle containing 0.85% of Fe element having a particle size of 0.18 μm.
The exception that the al ₂ O ₃ was prepared a magnetic tape in the same manner as in Reference Example 2. [0018] the exception that in Example 2 Si 0.20% of the abrasive particle size 0.23μ and Fe elements 1.15% containing α-Al ₂ O _3, the magnetic tape in the same manner as in Reference Example 2 Manufactured. Comparative Example 1 A magnetic tape was manufactured in the same manner as in Reference Example 1, except that the particle size of the abrasive was changed to 0.07 μm. Comparative Example 2 A magnetic tape was manufactured in the same manner as in Reference Example 1, except that the particle size of the abrasive was changed to 0.35 μm. Comparative Example 3 A magnetic tape was produced in the same manner as in Reference Example 1, except that the abrasive was changed to α-Al ₂ O ₃ having a particle size of 0.12 μm. Comparative Example 4 A magnetic tape was manufactured in the same manner as in Comparative Example 3, except that the particle size of the abrasive was changed to 0.21 μm. Comparative Example 5 A magnetic tape was manufactured in the same manner as in Comparative Example 3 except that the particle size of the abrasive was changed to 0.30 μm. Comparative Example 6 A magnetic tape was produced in the same manner as in Reference Example 2, except that α-Al ₂ O ₃ having a particle size of 0.20 μm coated with 1.20% of α-Fe ₂ O ₃ was used. Table 1 below shows the results of the characteristics of the above-described prototype magnetic recording medium. In the table, Br is the residual magnetic flux density, Bm is the saturation magnetic flux density, OR is the orientation ratio (the ratio of the magnetic flux density in the vertical direction / horizontal direction), and the unit of YS / N and CS / N is dB. [Table 1] The following can be confirmed from Table 1. When Comparative Examples 1, 2, and 3 with and without Si element are compared with Comparative Examples 3, 4, and 5, there is almost no difference in the magnetic characteristics, YS / N, and CS / N for each particle size. Although not seen, significant effects are seen on the adhesion of the magnetic head (number of clogging passes) and still life (durability of the magnetic tape). Comparison of the Presence or Absence of Fe Element When comparing Example 1 and Comparative Example 4, the magnetic properties, YS /
N and C / S / N also have an effect, and the number of clogging passes and still life (durability of magnetic tape) are also effective. As can be seen from Example 2 when Si and Fe elements are contained, there is a remarkable effect on durability and still life as in the case of using Si alone. Regarding the particle size when SiO ₂ is adsorbed When the particle size is 0.07 μm, the number of clogging passes and still life are good as compared with the case where Si or Fe is not adsorbed.
It is inferior to those having a particle size of 0.10 to 0.30 μm. In the case of 0.35 μm, the number of clogging passes and still life are good, but YS / N and CS / N
Is inferior to that of 0.10 to 0.30 μm. this is,
It is considered that the surface roughness was deteriorated due to the large particle size, and a spacing loss with the head occurred. Regarding the difference between Fe element containing and α-Fe ₂ O ₃ coating,
Comparing Comparative Example 6 Example 1 Te. When coated with α-Fe ₂ O ₃ , the number of clogging passes and inferior to the case where still life is included are inferior. As described above, according to the present invention, the adhesion of the magnetic head (the number of clogging passes) is reduced without sacrificing the magnetic characteristics, and the still life of the magnetic recording medium (the durability of the magnetic tape) is achieved. Can be improved.

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Hitoshi Kamigami               1-13-1 Nihonbashi, Chuo-ku, Tokyo               ー Decay Corporation                (56) References JP-A-63-96732 (JP, A)                 JP-A-3-86918 (JP, A)

Claims (1)

(57) [Claims 1] An average particle size of 0.10μ to 0.30μ,
0.5 to 3.0% Fe element, or 0.05 to 0.30
% Of Si element and 0.5 to 3.0% of Fe magnetism of α-Al ₂ O ₃ containing elemental formed by a magnetic coating material was dispersed in a binder with a magnetic powder is applied to the nonmagnetic support All the recording medium
Containing the Fe element or the Si element and the Fe element
Α-Al ₂ O ₃ is a compound having Fe element or Si
The compound having the element and the compound having the Fe element are referred to as α-
Must be obtained by mixing with the raw material of Al ₂ O ₃ and firing
A magnetic recording medium characterized by the above-mentioned.