JPH0363930A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To reduce the wear of a magnetic layer and to improve the durability of the medium by incorporating a compd. shown by a specified formula into the magnetic layer provided on a nonmagnetic substrate. CONSTITUTION:A compd. shown by formula I is incorporated into the magnetic layer provided on the nonmagnetic substrate. In the formula, R is 11-31C hydrocarbonic groups, 13-21C groups are preferably used, and 15-17C groups are most preferably used. A straight-chain or branched-chain R can be used, and the R may have a saturated or unsaturated bond. The amt. of the compd. to be incorporated into the magnetic recording medium is preferably controlled to 0.05-15pts.wt. based on 100pts.wt. of a magnetic material. Consequently, good lubricity is imparted, and the durability is drastically improved.

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 azides, 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 a compound represented by the following general formula (1). This is what we provide.

(In the formula, R represents a hydrocarbon group having 11 to 31 carbon atoms.) In the compound represented by the general formula (1) according to the present invention (hereinafter abbreviated as compound (1)), as described above, R
The number of carbon atoms is 11 to 31, preferably 13 to 21, and most preferably 15 to 17.

Further, R may be a straight chain or a branched chain, and further may be saturated or have an unsaturated bond.

The amount of compound (1) added to the magnetic recording medium in the present invention is preferably 0.05 to 15 parts by weight per 100 parts by weight of the magnetic material. 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 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 after forming the magnetic paint film. .

The same method can also be applied to media in which a magnetic layer is formed on a non-magnetic support by sputtering or vapor deposition.

The magnetic powder used in the magnetic recording medium of the present invention includes needle-shaped fine T FezO5+ Fe3O4, Crow
Metal oxides such as Co-coated-Fe, 0. ,
C.

Doped 7-Fe, γFe processed like 01
zes, 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 powders of metals or alloys such as Co, Fe-Co+Fe-Ni, and the like. 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. Further, in order to adjust the hardness of the resin, a plasticizer or a hardening agent may be added.

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 boria, HAI, metals such as Cu; paper, etc. are used. The form may be a film, tape, sheet, disk, card, drum, etc. Further, 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 1 part Vinyl chloride-vinyl acetate copolymer 11 Polyurethane resin 0 Carbon black (antistatic agent) Crz (h (abrasive) Toluene methyl ethyl ketone cyclohexanone note) 11 parts by weight 2 〃 10〃 71〃 71〃 107〃 Book 1: Union Carbide Co., Ltd., product name VAGH*2: Nippon Polyurethane Co., Ltd., product name N-2301 After mixing the above composition in a sand mill for 10 hours, take it out through a filter, and further Immediately before coating, 4.4 parts by weight of a hardening agent was added and stirred.This coating was applied on 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 to the disc.
Sample disks were prepared by applying the lubricant shown in Table 1 in an amount of 600 cm/bot.

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 Table 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 head was run continuously on the same track. The circumferential speed at this time is 7 m/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 as ◎, and the following ratings were given as 01△ and × in descending order of the number of scratches.

The results are shown in Table 3.

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 contains a compound represented by the following general formula (1). Medium. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(1) (In the formula, R represents a hydrocarbon group having 11 to 31 carbon atoms.)