JPH03194722A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To impart good lubricating ability to a medium and to improve durability by incorporating specified compd. into a magnetic layer. CONSTITUTION:The magnetic layer contains a compd. expressed by formula I, wherein R1 is hydrocarbon group having 3-23C, R2 is hydrocarbon group having 1-20C, R3 and R4 represent hydrogen atom or hydrocarbon or phenyl group having 1-8C. The adding amt. of the compd. is preferably 0.05-15 pts. wt. to 100 pts.wt. of the magnetic material. This compd. is impregnated into the magnetic layer by preliminarily mixing with the magnetic coating material or by dissolving in a all-purpose solvent, applying the solution on the magnetic coating film after forming and drying. By this method, good lubricating ability can be obtd. and the durability of the medium can be 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 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 inventors have 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, R1 represents a hydrocarbon group having 3 to 23 carbon atoms, R2 represents a hydrocarbon group having 1 to 20 carbon atoms, and R1Ra represents a hydrogen atom, a hydrocarbon group having 1 to 8 carbon atoms, or a phenyl group.) In the compound represented by the general formula (1) according to the invention (hereinafter abbreviated as compound (1)), R
1 is a hydrocarbon group having 3 to 23 carbon atoms, but the carbon number of R3 is preferably 11 to 21, and most preferably 13 to 17.Also, even if this R is a straight chain, it has a branch @ chain. Furthermore, it may have a saturated bond or an unsaturated bond.

R1 is a hydrocarbon group having 1 to 20 carbon atoms, and may be linear or branched.

R3 and R4 are a hydrogen atom, a hydrocarbon group having 1 to 8 carbon atoms, or a phenyl group, and particularly preferably a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms.

Compound (1) can be obtained by a normal esterification reaction between the fatty acid represented by the following formula (2) % formula % (2) and an alcohol represented by the following formula (3) 4 .

The alcohol represented by the general formula (3) can be prepared using a known method (for example, Org,
5ynth, , I [[, 502 (1955))].

In addition, the trimethylol compound represented by the general formula (5) is obtained by combining an aldehyde represented by the following formula (6) % formula % (6) and formaldehyde represented by the following formula (7) HCHO (7) with a base. It can be obtained by reacting in the presence of the compound according to the method disclosed in Japanese Patent Publication Nos. 62-8419, 61-148134, and 63-11333.

Typical aldehydes represented by the general formula (6) are propionaldehyde and butyraldehyde, but as described above, octylaldehyde, dodecylaldehyde, stearylaldehyde, etc. having longer chains can also be used.

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. It may be used in combination with esters such as esters, 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 the paint film by applying a solution of a general-purpose solvent such as isopropanol or hexane after forming the magnetic paint film and drying it. I can do it.

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 includes fine needle-shaped 7 FezO5+ FezO5+ Cro
Metal oxides such as W, and Co-coated T Fetus
,C.

γPe processed like doped 7-Fe, O,
g's, metallic iron powder, microplate-shaped barium ferrite and some of its Fe atoms are Ti, Co, and 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, 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; metals such as Al and 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 rays, 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 100 parts by weight Vinyl chloride-vinyl acetate copolymer” 11 Polyurethane resin *ffi 11 Carbon black (antistatic agent) 2 Cr, 0. (abrasive) 10 Toluene 71 Methyl ethyl ketone 71〃Cyclohexanone
107 Note) *l: 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 a curing agent was added immediately before coating. 4.4 parts by weight was added and stirred. This paint 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 disk 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 μ/M.

Table 1 Comparative Examples 1 to 4 Sample disks were prepared in exactly the same manner as in 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 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 ○, Δ, and × in descending order of the number of scratches.

The results are shown in Table 3.

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_1 is a hydrocarbon group having 3 to 23 carbon atoms, R_2
represents a hydrocarbon group having 1 to 20 carbon atoms, and R_3 and R_4 represent a hydrogen atom, a hydrocarbon group having 1 to 8 carbon atoms, or a phenyl group. )