JPS62125532A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To provide the excellent lubricity to the titled medium and to improve the durability even under extensive service conditions by incorporating an ester compd. shown by the specified general formula, squalene, and a fatty acid having the specified number of carbons into a magnetic layer. CONSTITUTION:From 1-15wt% of the ester compd. shown by general formula I, squalene, and the 8-28C fatty acid is incorporated into magnetic powder to form the magnetic layer. Excellent lubricity is provided to the magnetic recording medium using this magnetic layer and the durability is enhanced even under the extensive service conditions. In the formula, R1 and R2 are 1 1-25C (where the total number of carbons in R1 and R2 is 14-34) straight- chain or branched-chain saturated alkyl group and R3 is a 7-29C straight-chain or branched-chain saturated or unsaturated alkyl group.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to magnetic recording media. More specifically, it relates to magnetic recording media and bodies with excellent durability.

[Conventional technology and problems]

Magnetic recording media are made by coating a magnetic paint consisting of magnetic powder, binder resin, organic solvent, and other necessary components on a substrate such as a polyester film. Since the magnetic layer is easily abraded due to violent sliding contact with the magnetic head, jacket liner, etc., there is a need for a magnetic layer that is less abrasive and has excellent durability.

Therefore, as a measure to improve the wear resistance of the magnetic layer, various lubricants are mixed into the magnetic layer.

Conventionally used lubricants include fatty acids, oleyl oleate, butoxide stearate, fatty acid amides, liquid paraffin, wax, and the like. however,
At present, these lubricants cannot be said to be satisfactory in terms of performance. For example, oleyl oleate, butoxide stearate, etc. are insufficient for improving the durability of media, while fatty acids such as stearic acid and oleic acid, and hydrocarbon-based lubricants such as liquid paraffin are effective in improving durability. Although effective, it has poor compatibility with the binder, and when used in large quantities, it bleeds from the surface of the magnetic layer and tends to stain the head.

[Means for solving problems]

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 imparted with good lubricity and has significantly improved durability even under a wide range of usage environments.

That is, the present invention provides a magnetic recording medium having a magnetic layer on a non-magnetic support, in which the magnetic layer has the following general formula (I) υ (wherein R4 and R2 have a carbon number of 1 to 25 (wherein R1
and R2 have a total of 14 to 34 carbon atoms), and R3 is a linear or branched saturated or unsaturated alkyl group having 7 to 29 carbon atoms.

), squalane, and a carbon number of 8
-28 fatty acids.

[Effect]

The magnetic recording medium of the present invention includes the general formula (1) in the magnetic layer.
), squalane, and a fatty acid having 8 to 28 carbon atoms. These ester compounds, squalane and fatty acids are thought to act as lubricants. When used in combination,
Although excellent lubricity is imparted, the detailed reason is not clear.

The ester compound represented by the general formula (1) according to the present invention can be produced by, for example, an esterification reaction between a branched alcohol (this branched alcohol is called Guerbet alcohol because of its synthesis method) and a fatty acid. Obtainable. In the present invention, as described above, esters in which the sum of the carbon numbers of R5 and R2 is 14 to 34 are used, and those in which the sum of carbon numbers is 22 to 34 are particularly preferred.

Squalane according to the present invention is a hydrocarbon represented by the following formula (ff), and is 2.6.10.15.19.23-
Also called hexamethyltetracosane.

The fatty acid according to the present invention has 8 to 28 carbon atoms,
It may be saturated, unsaturated, linear, or branched. Specific examples of fatty acids include caprylic acid, capric acid, lauric acid, myristic acid, valmitic acid, stearic acid, isostearic acid, arachidic acid, behenic acid,
Examples include 12-stearic acid, oleic acid, linoleic acid, and erucic acid.

Further, the total amount of the ester compound, squalane, and fatty acid used is usually 1 to 100 parts by weight of the magnetic powder.
It is 15 parts by weight. In addition, the quantitative ratio of ester compound/fatty acid/squalane is 10-60% by weight for the ester compound, 10-50% by weight for the fatty acid, and 20-80% by weight for the squalane, taking the total of these three as 100% by weight. It is preferable to set it as %. Furthermore, the amount of squalane is at least 5
It is more preferable to set it to 0% by weight.

The magnetic powder according to the present invention is fine needle-shaped r-Fe.
Metal oxides such as 203, FexOa, Cr0z, as well as Co-coated r-Fe203, Co-doped γ-Fe, 0.
r-Fe, 03, iron metal powder, barium ferrite in the form of microplates, and some of its Fe atoms are one or more of Ti, Co, Zn, V, Nb, etc. Substituted magnetic powder, Co, Fe-Co, Fe-N
Examples include ultrafine powder of metals or alloys such as i. Among these, iron metal powder has particularly poor chemical stability, so to improve this, small amounts of nickel, cobalt, titanium, silicon, aluminum, etc. are added in the form of metal atoms, salts, and oxides, or the surface is treated. However, these can also be used. In order to stabilize iron metal powder, a thin oxide film may be formed on the surface in a weakly oxidizing atmosphere, and metal powder treated in this manner may also be used.

Examples of binders that can be used in the present invention include polyurethane, polyester, polyvinyl chloride,
Vinyl chloride vinyl acetate copolymer, polyacrylonitrile, nitrile rubber, epoxy resin, alkyd resin, polyamide, polyacrylic acid ester, polymethacrylic acid ester, polyvinyl acetate, polyvinyl butyral, vinylidene chloride, vinylidene chloride copolymer, nitrified cotton , maleic acid-modified vinyl chloride/vinyl acetate copolymer, ethyl cellulose, and the like.

Although these may be used alone, two or more types are usually used in combination. Furthermore, a plasticizer or a hardening agent may be added to adjust the hardness of the resin.

Further, the amount of the binder blended is generally 15 to 60 parts by weight per 100 parts by weight of the magnetic powder. Even if the binder has the highest binding strength, if the amount is less than 15 parts by weight, the strength of the magnetic coating will be weak and the adhesive strength between the substrate and the magnetic coating will be insufficient. On the other hand, if the amount is more than 60 parts by weight, the concentration of magnetic powder in the magnetic coating film becomes small, which is disadvantageous because the reproduction output decreases. Furthermore, the properties of the coating film may deteriorate.

〔Example〕

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

Examples 1 to 5 Using the lubricants shown in Table 1, mixtures having the compositions shown below were prepared.

Co-adhered 7-FezO: + 100 parts by weight PVC/vinyl acetate copolymer 30 Nitrile butadiene rubber 2 15 Carbon black 7 Aluminum oxide 6 Toluene 150 Methyl ethyl ketone 150 Lecithin 1 Lubricant 8 Note) Material U.C.C., USA Product name: V A G 1
1 bottle 2 Nippon Zeon Co., Ltd. (trade name: 1432J) Next, the above mixture was kneaded in a sand mill for 15 hours, and then 7 parts by weight of a polyisocyanate compound (trade name: Coronate, manufactured by Nippon Polyurethane ■) was added to form a total of 5 types of magnetic paint. was prepared. These paints were then applied onto a polyethylene terephthalate film with a thickness of 75 μm to a dry film thickness of 1.5 μm.
It was coated so as to have a thickness of μ, and after drying, it was calendered. Further, this was left at 60° C. for 4 days to undergo a hardening reaction, and then punched out into a disk shape and surface polished to produce a magnetic disk.

The durability of each magnetic disk was tested by loading these disks into a floppy disk accelerated durability test drive and measuring the running time at 5°C and 25°C until the playback output reached 70% of the initial output. was determined.

The results are shown in Table 1.

Table 1 Comparative Examples 1 to 4 Instead of the lubricant used in the example, 8 parts by weight of the various lubricants shown in Table 2 were used, the other components and their amounts were the same as in the example, and the method of the example was followed. A total of four types of magnetic paints were prepared accordingly. Magnetic disks were manufactured using these paints in the same manner as in the examples, and the durability of these disks was examined. The results are shown in Table 2.

Table 2

Claims (1)

[Claims] 1. In a magnetic recording medium having a magnetic layer on a non-magnetic support, the magnetic layer has the following general formula (I) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼... I) {In the formula, R_1 and R_2 have a carbon number of 1 to 25 (however, R
The sum of the carbon numbers of _1 and R_2 is 14 to 34) is a linear or branched saturated alkyl group, and R_3 is a saturated alkyl group having 7 to 7 carbon atoms.
It is a saturated or unsaturated alkyl group having 29 straight or branched chains. } An ester compound represented by, squalane, and a carbon number of 8
A magnetic recording medium characterized by containing ~28 fatty acids.