JPS60136033A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve runnability by adding a specific compd. as a lubricant to a medium. CONSTITUTION:A magnetic layer 2 contg. a lubricant is formed on the surface of a non-magnetic base 1. The layer contg. the lubricant is shown by the dotted section. Triester of tris-(2-hydroxyethyl)isocyanurate and fatty acid is used as a solvent. The magnetic powder usable for the magnetic layer includes gamma-Fe2O3, Fe3O4, gamma-Fe2O3, Fe3O4 doped or deposited with cobalt, etc. The binder usable for the magnetic layer includes a vinyl chloride/vinyl acetate copolymer, vinyl chloride/vinyl acetate/vinyl alcohol copolymer, etc. Acetone, methyl ethyl ketone, methyl isobutyl ketone, etc. are used alone or as a mixture as an org. solvent in preparing the magnetic paint. Polyester such as polyethylene terephthalate or the like is used as the non-magnetic base to be coated thereon with the magnetic paint adjusted with said org. solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording medium having a magnetic layer on a non-magnetic support, such as a magnetic tape or a magnetic disk.

Magnetic tapes are particularly required to have various properties, including a low coefficient of friction, smooth and stable running properties, a small amount of powder falling off, and good splicability. That is, when a magnetic tape is used in a magnetic recording/reproducing device such as a VTR, it runs at high speed while physically contacting tape guides, magnetic heads, etc., so it has excellent wear resistance and remains stable for a long time. For example, if the WL friction coefficient of the tape case changes during recording or playback, the tape will vibrate at the guide or magnetic head, and as a result, the recording/playback process on the tape will be affected. There are disadvantages in that the frequency of the sound (for example, tone reconnaissance sound) changes, resulting in a sound different from the facial wave number, or that the vibration sound of the tape (so-called Q sound) can be directly heard.

In order to prevent this, various attempts have been made to impart magnetism to the tape. For example, solid particles such as molybdenum disulfide, graphite, wax, etc. are added to a magnetic paint containing magnetic powder and a binder. However, this solid gradual release is not desirable because it is not very effective for durability and also deteriorates magnetic properties when added in a large amount.

On the other hand, higher fatty acids, higher fatty acid esters, paraffinic hydrocarbons, silicone oils (e.g. dimethyl silicone oil, diphenyl silicone oil), etc. may be used as lubricants, but even these may provide sufficient durability and lubricity. This is particularly insufficient for VTR cassettes. Moreover, blooming, which is a slippery ooze on the surface of the magnetic layer, is likely to occur, causing tape sticking phenomena, stain slips, and the like.

The present invention has been made to correct the above-mentioned defects, and an object of the present invention is to improve the running properties of a magnetic recording medium by using a novel lubricant.

That is, the present invention relates to a magnetic recording medium having a magnetic layer on a non-magnetic support, characterized in that the magnetic recording medium retains an ester of tris(2-hydroxyethyl)isocyanurate and a fatty acid. It's about the medium.

As the ester of tris(2-hydroxyethyl)isocyanurate and fatty acid, triester can preferably be used. Both saturated and unsaturated fatty acids can be used. When a fatty acid is shown as RCOOH, the hydrocarbon group R
The number of carbon atoms is 7 to 21.0'! ``'''' Preferably 5 Pa/Less than 7 A/'' Smoothness and functional ability '1 will be poor. the other 2
If the lubricant is difficult to obtain if it exceeds 1, the amount of the lubricant used in the invention, when included in the magnetic layer, is 0.2 to 4 parts by weight per 100 parts by weight of the magnetic powder in the magnetic layer. PHP)
It is preferable that In addition, when it is included in the back coat layer (described later) on the back of the base, 0.2 to 20 parts by weight (PIIR) per 100 parts of the binder in the bank coat layer.
It is desirable that Furthermore, when coating Tosopko-H5t or a coating layer (both described below) made of the above-mentioned lubricant, the amount of the lubricant applied is
It is desirable that the ratio is o■/d.

Furthermore, it is also possible to use the lubricant according to the invention in combination with other conventional lubricants mentioned above.

A magnetic recording medium, such as a magnetic tape, according to the present invention is illustrated in FIGS. 1 to 5.

FIG. 1 shows a magnetic layer (2) containing the lubricant of the present invention formed on the surface of a non-magnetic base (1). In the following figures, the layer containing the lubricant according to the invention is shown in large-scale cross-sections. FIG. 2 shows a state in which a top coat layer (3) made of a lubricant according to the present invention is formed on the surface of a magnetic layer (2). Figure 3 shows a coating layer (4) made of a lubricant according to the present invention on the back side of the non-magnetic base +11.
FIG. 4 shows a state in which a non-magnetic base (1
FIG. 5 shows a state in which the lubricant according to the present invention is contained in the bank coat layer (5) formed on the back surface of
A coating layer (6) made of a lubricant according to the present invention is shown formed on a back coat layer +51. The back coat layer (5) is provided for various purposes, including stabilizing runnability by appropriately controlling the surface roughness of the back surface, and preventing static electricity. For this purpose, the bank coat layer may be coated with a binder mixed with carbon black, or may be further mixed with a non-magnetic pigment such as α-Fe20i, alumina, talc, etc. The magnetic recording medium of the present invention can be applied not only to such magnetic tapes but also to magnetic disks having magnetic layers on the front or back surfaces. Further, the lubricant according to the present invention can be held at various positions in the magnetic layer (2) or on the front and/or back surface of the magnetic layer (2).

As the magnetic powder that can be used in the magnetic layer of the present invention, γ-Fe
2O3, F111304.7 Pe20i and Fea04
mixed crystal with cobalt doped or coated rPe
J3 or Fe50+, CrO2, barium ferrite, various alloy powder magnetic materials (e.g. p6-Co, Co-
Nf, FeC.

-Nis Pe -Go -B % Pe -Co -
Cr-B% Mn-old, Mn-AI, Fe-C
o -V, etc.), iron nitride, etc., these two
More than one species may be mixed and used at °C.

Examples of RIJ-capable binders used in the magnetic layer include vinyl chloride-vinyl acetate-#I: polymer, vinyl chloride-vinyl acetate-#I: vinyl alcohol copolymer, vinyl chloride-vinyl acetate-maleic acid copolymer, Vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, acrylic ester-acrylonitrile copolymer, acrylic ester-vinylidene chloride copolymer, methacrylic ester-hynylidene chloride copolymer, methacrylic ester- Styrene copolymer, thermoplastic polyurethane resin,
Phenoxy resin, polyvinyl fluoride, vinylidene chloride-acrylonitrile copolymer, butadiene-acrylonitrile copolymer, acrylonitrile-butadiene-methacrylic acid copolymer, acrylonitrile-butadiene-acrylic acid copolymer, polyvinyl butyral, polyvinyl acetal, cellulose Examples include derivatives, styrene-butadiene copolymers, polyester resins, phenol resins, epoxy resins, thermosetting polyurethane resins, urea resins, melamine resins, alkyd resins, urea formaldehyde resins, and the like.

When preparing the magnetic paint, use organic solvents such as ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; alcohols such as methanol, ethanol, propatool, and butanol; ethyl acetate, butyl acetate, ethyl lactate, glycol acetate, Esters such as monoethyl ether; glycol ethers such as ethylene glycol dimethyl ether, ethylene glycol monoethyl ether, dioxane; benzene,
Aromatic hydrocarbons such as toluene and xylene; aliphatic hydrocarbons such as hexane and heptane; nitropropane and the like can be used alone or as a mixture. This is used as a non-magnetic base to apply magnetic paint adjusted with organic solvent.
Examples of ζ include polyesters such as polyethylene terephthalate, polyolefins such as polypropylene, cellulose derivatives such as cellulose triacetate and cellulose diacetate, polycarbonate, polyvinyl chloride, polyamide, polyimide, metal materials such as aluminum and copper, paper, etc. . In addition, Freon,
Low boiling solvents such as hexane, ethanol, etc. may be used.

Further, magnetic recording media to which the compound of the present invention is applied as a lubricant are not limited to so-called coating-type magnetic recording media in which a magnetic layer is formed by coating together with magnetic powder and a binder as described above, but also metal ferromagnetic 'a Pear-shaped magnetic recording media are also commonly used. This metal ferromagnetic thin film magnetic recording medium is formed by plating, vapor deposition, ion blasting, sputtering, or the like with a magnetic metal such as Co, Fe, Ni, or an alloy thereof on a nonmagnetic support -F. This metal ferromagnetic thin film magnetic recording medium has a high magnetic flux density because it does not require the use of a binder, and is useful for short wavelength, high density recording because it is formed into a very thin layer.

The present invention and examples will be explained below.

Example 1 Part by weight Co deposited 7-Fe2O3' 100 Carbon (antistatic agent) 5 Lecithin (dispersant) 1 Methyl ethyl ketone 150 Methyl isobutyl ketone 150 The above composition was used as a basic composition, and Tris (
1 part by weight of triester of 2-hydroxyethyl) isocyanurate and oleic acid was added and milled in a ball mill for 24 hours.
After mixing for a period of time, the mixture was taken out through a filter, and immediately before coating, 4 parts by weight of a curing agent was added and stirred for 30 minutes. This magnetic paint was applied onto a polyethylene terephthalate base having a thickness of 12 μm so that the thickness after drying would be 5 μm, and after magnetic field orientation, it was dried and rolled up. This was calendered and then cut into 1/2 inch width to prepare sample tapes.

Example 2 A sample tape was prepared in the same manner as in Example 1 using a magnetic paint in which 1 part by weight of triester of tris(2-hydroxyethyl)isocyanurate and myristic acid was added to the basic composition of Example 1. did.

Example 3 A sample tape was prepared in the same manner as in Example 1 using the basic composition of Example 1 as a magnetic paint. Tris(2-hydroxyethyl) was added to the magnetic layer of the sample tape above.
1. Triester of isocyanurate and oleic acid.
A sample tape was prepared by applying (top coat) an Owt% n-hexane solution such that the coating amount of triester was 160 .mu./-.

Example 4 A sample tape was prepared in the same manner as in Example 1 using the basic composition of Example 1 as a magnetic paint. Tris(2-hydroxyethyl) was added to the magnetic layer of the sample tape above.
1. Triester of isocyanurate and isostearic acid. A sample tape was prepared by applying (top coat) a kt% n-hexane solution so that the coating amount of triester was 160 μ/lri.

Comparative Example The basic composition of Example 1 was used as a magnetic paint. A sample tape was prepared in the same manner as in Example 1.

The properties of the sample tapes prepared in the above Examples and Comparative Examples are shown in the following table.

Table In this table, ◎ indicates extremely good, ◯ indicates good, △ indicates poor, and × indicates extremely poor.

Further, aging was carried out for 3 days at 40° C. and 80% condition -1.

As can be seen from the table, in the magnetic recording medium according to the present invention, the coefficient of friction can be suppressed to an extremely small value, and stick-slip can be avoided. In particular, according to the present invention, running deterioration due to aging, which has conventionally been a problem with magnetic recording media using the top coat method, can be solved.

[Brief explanation of drawings]

1 to 5 are cross-sectional views showing embodiments of magnetic recording media according to the present invention. +11 is the base, (2) is the magnetic layer, (3) is the top coat, +41. (61 is a residue coating layer, (5) is a bank coat 1-.

Claims (1)

[Claims] A magnetic recording medium having a magnetic layer on a non-magnetic support, characterized in that the magnetic recording medium contains an ester of tris(2-hydroxyethyl) isocyanurate and a fatty acid.