JPH0335414A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve durability of the medium by incorporating a specified epoxy compd. into the magnetic layer. CONSTITUTION:An epoxy compd. expressed by formula I is incorporated into the magnetic layer. In the formula, (n) and (l) represent 0 or integers from 1 to 23, (m) is 1 or 2, and R represents a hydrocarbon group with 1 - 18 carbon atoms. This epoxy compd. may be mixed beforehand with the coating material, or dissolved in a general purpose solvent such as isopropanol, hexane, etc., to prepare a solution, applied on the magnetic coating film after the film is formed, and then dried. Thereby, the obtd. magnetic layer has enough lubricating property and improved wear resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording medium, and more particularly to a magnetic recording medium with excellent durability.

[Prior art and problems to be solved by the invention] Magnetic recording media slide violently against magnetic heads and pads during recording and reproduction, and the magnetic layer is easily abraded, so the magnetic layer has less wear and is highly durable. something is desired.

Therefore, as measures to improve the wear resistance of the magnetic layer, methods such as an internal addition method in which various lubricants are mixed into the magnetic layer, or a top coating method in which a lubricant layer is formed on the surface of the magnetic layer have been used.

Conventionally used lubricants include higher fatty acids and their esters, fatty acid amides, liquid paraffin, and silicone oils.

However, it is currently difficult to say that these lubricants are satisfactory in terms of performance.

[Means to solve the problem]

The present inventor has arrived at the present invention as a result of intensive research in order to obtain a magnetic recording medium that is provided with good lubricity and has significantly improved durability.

That is, the present invention provides a magnetic recording medium having a magnetic layer on a non-magnetic support, wherein the magnetic layer contains an epoxy compound represented by the following general formula (1). It provides:

(In the formula, n and l are 0 or an integer of 1 to 23, m is 1 or 2, and R represents a hydrocarbon group having 1 to 18 carbon atoms.) In the epoxy compound (hereinafter abbreviated as epoxy compound (1)), n and l are O or an integer from 1 to 23 as described above, but preferably 8<n+1<20. Alternatively, R is a hydrocarbon group having 1 to 18 carbon atoms, and may be linear, branched, saturated, or unsaturated. m is 1 or 2, more preferably 1.

The amount of the epoxy compound (1) added to the magnetic recording medium in the present invention is 0.05 to 1 per 100 parts by weight of the magnetic material.
5 parts by weight is preferred. Further, if necessary, it may be used in combination with other general-purpose lubricants, such as esters such as butyl stearate, fatty acids such as oleic acid, and hydrocarbons such as squalane.

The epoxy compound (1) in the present invention can be used by being mixed into the paint in advance, or by impregnating it into the paint film by applying a solution of a general-purpose solvent such as isopropanol or hexane and drying it after forming the magnetic paint film. can.

Further, a medium in which a magnetic layer is formed on a non-magnetic support by sputtering or vapor deposition can also be coated and used in the same manner.

The magnetic powder used in the magnetic recording medium of the present invention is fine needle-shaped T Fe1Oi+ Fe1Oi+ Cru
Metal oxides such as
O-doped γ-Fe, γF processed like 03
ezes, metallic iron powder, barium ferrite in the form of microplates and some of its Fe atoms are Ti, Co, Zn.

Magnetic powder substituted with one or more of V, Nb, etc.
Examples include ultrafine powder of metals or alloys such as Co, Fe-Co, and Fe-Ni. Among these, metallic iron powder is particularly unstable chemically, and in order to improve this, metal atoms such as nickel, cobalt, titanium, silicon, and aluminum are added.
Salts and oxides, which are sometimes added in small amounts or surface treated, can also be used. Metallic iron powder may also have a thin oxide film formed on its surface in a weakly oxidizing atmosphere to stabilize it, and metal powder treated in this way can also be used. Further, two or more kinds of the above-mentioned magnetic powders may be mixed and used.

Examples of the binder used in the present invention for dispersing magnetic powder to form a magnetic layer include polyurethane, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyacrylonitrile, nitrile rubber, epoxy resin, Alkyd resin, polyamide, polyacrylic ester,
Examples include polymethacrylic acid ester, polyvinyl acetate, polyvinyl butyral, vinylidene chloride, nitrified cotton, maleic acid-modified vinyl chloride/vinyl acetate copolymer, and ethyl cellulose.

These may be used alone or in combination of two or more, and a plasticizer or curing agent may be added to adjust the hardness of the resin.

In addition to the above-mentioned components, additives such as abrasives and antistatic agents commonly used in this field can be added to the magnetic layer of the magnetic recording medium of the present invention.

In addition, non-magnetic supports used in manufacturing the magnetic recording medium of the present invention include polyesters such as polyethylene terephthalate; polyolefins such as polyethylene and polypropylene; cellulose derivatives such as cellulose triacetate and cellulose diacetate; polycarbonate; Vinyl chloride; polyimide; plastics such as aromatic polyamide HAI; metals such as Cu; paper, etc. are used. The support may be in any form such as a film, tape, sheet, disk, card, or drum, and the surface of the support may be treated with corona discharge, radiation, ultraviolet light, etc., or may be precoated with a suitable resin.

〔Example〕

EXAMPLES The present invention will be explained in more detail below with reference to Examples, but it goes without saying that the present invention is not limited to these Examples.

Examples 1 to 4 Metallic iron powder Vinyl chloride-vinyl acetate copolymer 0I Polyurethane resin 0 Carbon black (antistatic agent) Cr, 02 (abrasive) Toluene methyl ethyl ketone cyclohexanone Note) 100 parts by weight 11 11 2 1O 71 〃 71〃 107〃 *lH Union Carbide Co., Ltd., product name VAGH Umbrella 2 Nippon Polyurethane Co., Ltd., product name N-2301 After mixing the above composition in a sand mill for 10 hours, it was taken out through a filter, and then a curing agent was added just before coating. 4.4 parts by weight of was added and stirred. This paint was applied to both sides of a 32μ thick polyethylene terephthalate film so that the magnetic layer thickness after drying would be 4μ, dried and rolled up. This was calendered and cured, then punched out into a disc shape, and a 2.0% by weight isopropanol solution of the lubricant shown in Table 1 was added.
A sample disk was prepared by applying the lubricant shown in Table 1 in an amount of 600 u/nt.

Table Comparative Examples 1 to 4 Sample disks were produced in exactly the same manner as Examples 1 to 4, except that various lubricants shown in Table 2 were used instead of the lubricants used in Examples 1 to 4.

Table 2 Test Examples To examine the durability of the sample disks obtained in Examples 1 to 4 and Comparative Examples 1 to 4, each sample disk was housed in a shell lined with nonwoven fabric, loaded into a recording and reproducing device, and the same The head was run continuously on the track. The circumferential speed at this time is 7-/sec.

Damage to the magnetic layer of the sample disk after a certain number of baths was visually evaluated. The state with no scratches was rated O, and the ratings were rated as ○, Δ, and × in descending order of the number of scratches.

The results are shown in Table 3.

table

Claims (1)

[Scope of Claims] 1. A magnetic recording medium having a magnetic layer on a non-magnetic support, characterized in that the magnetic layer holds an epoxy compound represented by the following general formula (1). recoding media. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(1) (In the formula, n and l are 0 or integers from 1 to 23, m is 1 or 2, and R represents a hydrocarbon group having 1 to 18 carbon atoms.)