JPS5856227A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve the wear resistance of a magnetic head well as the wear resistance of a magnetic recording medium containing said magnetic head, by adding a specific amount of both Al2O3 of a specific particle size and the nonmagnetic powder of a specific degree of hardness to the magnetic powder contained in a magnetic layer. CONSTITUTION:A magnetic layer is formed on a support. This magnetic layer contains magnetic powder, Al2O3 having 0.005-0.1mu particle size and the nonmagnetic powder of Cr2O3, alpha-Fe2O3, alpha-Al2O3, SiC, SiO2, etc. having 0.3-2.0mu particle size and >=5Mohs hardness. The total content of Al2O3 and the nonmagnetic powder is set at 0.5-20wt% based on the magnetic powder. At the same time, the proportion of the Al2O3 powder to the nonmagnetic powder is set preferably within a range of (1:20)-(1:1) by weight.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to magnetic recording media. More specifically, the present invention relates to a magnetic recording medium in which the abrasion resistance of a magnetic layer and the abrasion resistance of a magnetic head are improved.

Magnetic recording media for t-tio, video, and computers come into intense contact with magnetic heads during recording and reproduction, and therefore are required to have magnetic layers that are less abrasive and have excellent rigidity.

For this reason, c' of Cr2U3 powder and At203 powder
) is much harder than magnetic powder, and its particle size is comparable to (or even larger than) magnetic particles.It has been proposed that it be mixed into the magnetic layer as a reinforcing additive. .

But these reinforcing additives? If it is mixed in, surface j abrasion properties will be improved, but on the other hand, the surface j will be improved. There is a risk of wear and tear.

On the other hand, S powder processing also uses Cr2U with small particle size.
Non-1i8tl powder like a powder, At203 powder? Although there is no risk of wear and tear on the magnetic head, the wear resistance of the magnetic layer will not be sufficiently improved.

The object of the present invention is, firstly, to provide a magnetic recording medium tray with improved abrasion resistance of the magnetic layer, and secondly, to provide a magnetic recording medium tray that does not cause wear and damage to the magnetic head. There is something to do.

The above object of the present invention is to provide At2 of o, oos, o, tμ.
03 powder, and a Mohs hardness of j or higher and 0.3 to -2.
0μ non-magnetic powder and km magnetic powder. , t--i!
It can be obtained by adding Owt%.

As the blending ratio of At203 powder increases, the wear of the magnetic head decreases, but when the amount exceeds the same amount, the effect of improving the wear resistance of the magnetic recording medium decreases. Therefore, the ratio of Az2o3 powder and non-magnetic powder is /:20. /: I is preferable, and At2υ3 mixed at the above blending ratio
powder and non-rJB powder (e.g. Cr2U3, α-F
e 203 , α-A12cJ3, Si0%5i02, etc.) are O, S ~
By adding 20 wt %, excellent wear resistance of the magnetic layer is obtained. When it exceeds 20 wt%, head wear increases and the 11i magnetic conversion characteristics deteriorate.

The magnetic layer of the present invention basically consists of magnetic powder dispersed in a binder, which contains the above-mentioned At2 (J3) and non-magnetic powder. Therefore, the magnetic powder and binder are not particularly limited. Specific examples of magnetic powder (ferromagnetic powder) include γ-Fe2O3, Fe3U4,
CO modified iron oxide, Fe-C.

Alloy, Ba ferrite, Fe-Co-Ni alloy, Fe
-Co-Cu alloy, etc. Binders include vinyl chloride-vinyl acetate copolymer, epoxy resin, polyamide resin, original resin, melamine resin, phenol resin,
Examples include cellulose derivatives. The magnetic layer, magnetic recording medium, and manufacturing method of the present invention are described in Japanese Patent Application Laid-open No.
Just follow the numbers etc.

The magnetic recording medium of the present invention can be applied to video tape recorders, audio tape recorders, computers, etc.

The present invention 7 will be explained in more detail with reference to Examples r below. In Examples, "1 part" indicates "overlapping part".

Example 1 The following composition was dispersed in a grape mill and coated with a removable layer.
r prepared, dry the raw cloth to a dry thickness of jμ on a polyester base film with a thickness of 2/jμ, and then mirror-finish it with a calendar roll. It was then cut into a predetermined width to produce a magnetic recording medium.

Magnetic layer composition cobalt modified iron oxide ioo part γ-At
2υ3 (particle size o, o, iμ) shown in Table 1 -tit
Magnetic powder with hardness above Mohs hardness (particle size o3μ) Nitrocellulose 6. J part polyurethane side fat / 2.6 parts carphone black Co, J part lubricated cutting
R, J part hardening
Saddle, θ section bath cut /
30 copies of the magnetic recording medium obtained in Sample 2/, filled into a videotape recorder, and steel percentage? It was measured. Also, the amount of wear on the magnetic head was measured by running the magnetic 6-pin recording medium repeatedly in the playback state for 00 hours. It was measured.

The results are shown in Table 1. Note that steel properties are an index of wear resistance, and the longer this time, the better the wear resistance.

As is clear from Table 1, γ-At203 with a particle size of o, ooz ~ 0,1μ and a particle size of 0 are used as reinforcing additives.
．． 3-2.0μ and Mohs hardness! Magnetic recording media according to the present invention using the above non-magnetic powder in combination with a tray (samples 1 to 6.
Samples 7 to ir) are magnetic recording media for comparison (samples 7 to l, l).
21) Yoshi, S1- Tail durability is long and head wear is also less.

From this, the magnetic layer according to the present invention has excellent abrasion resistance, and
'6 The amount of wear on the head is improved.

A- Example A magnetic recording medium was prepared in the same manner as in Example 1 except that the following composition was used. Prepared.

Magnetic layer composition cobalt modified iron oxide 100 parts γ-At
203 (particle size O, OSμ) amount α-A shown in Table 2
Ja 203 (particle size 0.3μ) Vinegar e
Vinyl-vinyl alcohol copolymer Wr polyester polyurethane 70 parts Carbon black 1 part Lubricant
curing agent
r part bath additive 1
Thirty samples were obtained, two of which were attached to a video tape recorder, and the stealth characteristic sound was measured. In addition, the sample was repeatedly run in the reproducing state for 0/θO time, and the wear noise of the magnetic head was measured. Results 7 are shown in Table 2. In the table, the still characteristics are an index of wear resistance, and the longer the time, the better the wear resistance. show.

-Tar-/O- As is clear from Table 2, γ-At2 (J3 and α-A,
The magnetic recording medium using Ja2O3 and r in combination has stealth characteristics ItCp, and the amount of head wear is less than that using only α-At2U3. Moreover, the magnetic i of the present invention
Among the recording media, ii of γ At2U3 is α-At2
The smaller the amount of U3, the better the stealth characteristics.

Patent applicant: Fuji Photo Film Co., Ltd. - / l - Procedural amendment filed in 1982, 2 and 10 days, dated November 9, 1981, Commissioner of the Patent Office, Shima 1) Haruki Tono 1, Indication of the case, 1978 patent First request 322≠
No. 2, Name of the invention Magnetic recording medium 3, Relationship with the person making the amendment Patent applicant Address 210 Nakanuma, Minamiashigara City, Kanagawa Prefecture Contact address Fuji Photo Film Co., Ltd. 2-26-30 Nishiazabu, Minato-ku, Tokyo 106 Company Tokyo Head Office Telephone: (406) 2537 Table Target of Amendment Column of “Detailed Description of the Invention” of Specification & Contents of Amendment (1) Amend “Contact” to “Sliding Contact” in all lines, page 1, line 77 of the specification of the application .

(2) On page 1 of the same line, correct the sentence ``It is a magnetic layer'' and ``It has a magnetic layer association.''

(3) Delete "Haruka" at the end of the first page of the same book.

(4) Ibid., page 2, line 77-lr, ``obtained'' is amended to ``achieve''.

(5+ Insert "For magnetic powder" in front of the line "Blending ratio" on page 1 of Doso.

(6) Page 3 of the same book, line 7 “J e rwt more than wt%
% more than that.”

(7) On page 3 of the same book, //line "in the binder" is corrected to "in the binder and inside".

(8) ``Therefore'', page 3, line 73? "Here," I correct.

(9) The same book, page 5, line 1, page t, line 72, and ! Page -/- Correct the last line to the last line as "Still" in the page/line.

00) ``Mounting'' on page 6 of the same book is corrected to ``loading''.

01) Table 1 on pages 7 to r of Doso and Table 2 on page 10 will be amended as shown in the attached sheets.

-Ko-

Claims (1)

[Claims] The support body and the magnetic layer provided thereon are composed of (lla powder, (2) particles f (1; l, 0
06-0, / μ (D A, 1203 and (3) particles f i: l: 0, j ~ co, θ μ, including non-a powder with a Mohs hardness of j or more, and the sum of At203 and non-extractable powder A magnetic recording medium characterized in that the content is (0.j, -20 wt % based on the weight of the material).