JPH02285511A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain the magnetic recording medium provided with good lubricity and with the durability improved by providing a magnetic layer on a nonmagnetic substrate and incorporating a specified ether compd. into the magnetic layer. CONSTITUTION:A magnetic layer is provided on a nonmagnetic substrate, and an ether compd. shown by formula I is incorporated into the magnetic layer. In the formula, R1 is 2-30C hydrocarbonic groups, R2 is hydrogen atom, 1-8C aliphatic hydrocarbonic group or aryl group, and R3 and R4 are respectively hydrogen atom, 1-8C aliphatic hydrocarbonic groups or aryl groups with the number of carbons in R1>=the number of carbons in R2. As a result, the wear of the magnetic layer is reduced, and durability is 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 an ether compound represented by the following general formula (1). It provides:

(In the formula, R is a hydrocarbon group having 2 to 30 carbon atoms, R2 is a hydrogen atom, an aliphatic hydrocarbon group having 1 to 8 carbon atoms or an aryl group, R3 and R4 are each a hydrogen atom, and 1 to 8 carbon atoms.
represents an aliphatic hydrocarbon group or an aryl group. However, R1
Carbon number≧R2 carbon number. ) In the ether compound represented by the general formula (1) according to the present invention (hereinafter abbreviated as ether compound (1)), the number of carbon atoms in R1 is 2 to 30 as described above, but especially 8 to 22 carbon atoms. , and even 12~
20 is preferred. Further, R8 may be linear or branched, and may be saturated or have an unsaturated bond.

R2 is a hydrogen atom, a linear or branched aliphatic hydrocarbon group having 1 to 8 carbon atoms, or an aryl group, and particularly preferably a hydrocarbon group having 1 to 2 carbon atoms or a hydrogen atom.

In addition, R3 and R4 are each a hydrogen atom and have a carbon number of 1 to 8.
is an aliphatic hydrocarbon group or an aryl group, preferably a methyl group.

Ether compound (1) can be synthesized, for example, by a known method as shown below.

That is, the glycidyl ether represented by the following formula (2) and the benzyl alcohol represented by the following formula (3) are combined with a suitable catalyst (for example, an alkali metal hydroxide such as LiOH, NaOH, NaOMe, Na0Et, etc.). -BuO
by a known method in the presence of alkali metal alcoholides such as K, tertiary amines such as triethylamine, tributylamine, and tetraethylenediamine, protonic acids such as sulfuric acid and hydrochloric acid, and Lewis acids such as boron trifluoride ether complexes. The reaction results in an alcohol compound represented by formula (4).

Q-CH20H R1-C-R4 υN This alcohol compound and epichlorohydrin represented by formula (5) are reacted by a known method to obtain an ether compound represented by formula (6).

υ The ether compound represented by formula (6) and the ketone (or aldehyde) represented by formula (7) are prepared by a known method (e.g. J, Am, Oil Chem, 5oc-+
65+1299 (1988)) by reducing the compound represented by formula (8) with hydrogen using palladium carbon as a catalyst.
A compound of formula (9) can be obtained.

When an aliphatic hydrocarbon group or an aryl group is further introduced into the alcohol moiety of the compound represented by formula (9) through an ether bond, the compound represented by formula (9) is treated with an alkali metal (e.g. Na, The alcoholade obtained by reacting with K) and the haloalkyl represented by 200) may be reacted by a known method.

lhX Qo) (where X represents a halogen such as CI, Br, I, etc.) The amount of the ether compound (1) added to the magnetic recording medium in the present invention is 0.05 to 15 parts by weight per 100 parts by weight of the magnetic material. 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 ether 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 isopropyl alcohol or hexane and drying it after forming the magnetic paint film. 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 is fine acicular powder. 'FezO,,,Fe:104+C
Metal oxides such as r0z, as well as Co-deposited - FezO
,,,C.

γFe processed like doped γ-Fe203
2O3, metallic iron powder, barium ferrite in the form of microplates and some of its Fe atoms are Ti, Co, and Zn.

ν, magnetic powder substituted with one or more types such as Nb,
Examples include ultrafine powder of metals or alloys such as Co, Fa-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 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 polyamide; metals such as Al and 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 100 parts by weight Vinyl chloride-vinyl acetate copolymer Width 11〃Polyurethane resin''
11//Carbon black (antistatic agent) 2 Cr2O:+ (abrasive) 10 Toluene 71 Methyl ethyl kene 71 Cyclohexanone
107 Note) *1: Product name manufactured by Union Carbide Co., Ltd. V A G H *
2: Trade name N-2301 manufactured by Nippon Polyurethane Co., Ltd. The above composition was mixed in a sand mill for 10 hours, taken out through a filter, and immediately before coating, 4.4 parts by weight of a curing agent 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 applied to the disc so that the coating amount of the lubricant shown in Table 1 was 600 cm/bot. A sample disk was prepared by applying the following coating.

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. A state with no scratches was rated as ◎, and evaluations were made as O1△ and × in descending order of the number of scratches.

The results are shown in Table 3.

q

Claims (1)

[Scope of Claims] A magnetic recording medium having a magnetic layer on a non-magnetic support, characterized in that the magnetic layer holds an ether 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 with 2 to 30 carbon atoms, R_2
represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 8 carbon atoms, or an aryl group, and R_3 and R_4 each represent a hydrogen atom, an aliphatic hydrocarbon group having 1 to 8 carbon atoms, or an aryl group. However, R_1 carbon number≧R_2 carbon number. )