JPS5994239A - Magnetic recording medium and its production - Google Patents

Abstract

PURPOSE:To improve wear and running stability without deteriorating the electromagnetic conversion characteristic at a short wavelength by using at least fatty amide as an essential component in an org. lubricant layer which is laminated in a prescribed amt. by a vacuum deposition method on a thin ferromagnetic film. CONSTITUTION:An org. lubricant layer which consists essentially of at least fatty amide and has 10X10<-8>-100X10<-8>g/m<2> lamination quantity is laminated by a vacuum deposition method on the surface of a thin ferromagnetic film in a vacuum deposition device. Such lamination quantity poses no particular problem in an electromagnetic conversion characteristic (for example, wavelength lambda= 0.85mum). The lamination quantity is controlled by controlling the temp. in the vessel for a vapor source which is disposed in the vacuum deposition device and is packed therein with an org. lubricant. The org. lubricant consists essentially of at least fatty amide and contains other components such as fatty acid, fatty ester or the like. The fatty amide used as the essential component is preferably an amide of >=12 C fatty acid. For example, lauric amide, myristic amide, etc. are enumerated for such fatty amide.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a magnetic recording medium with excellent wear resistance and running properties, in particular a magnetic recording medium in which the magnetic layer is composed of a ferromagnetic thin film, 2. The present invention relates to a binder-type magnetic recording medium and its manufacturing method, and the magnetic recording medium according to the present invention is used in audio tape decks, video tape recorders, and PCs! It is applied to MFF magnetic recording devices, large computers, terminal data processing devices such as personal computers, etc.

Conventional structure and its problems A magnetic layer is deposited on a non-magnetic substrate by vacuum evaporation, sputtering,
Binder-free magnetic recording media, which are composed only of ferromagnetic thin films using thin film forming methods such as ion plating and do not contain binders or additives, have excellent electromagnetic conversion characteristics at short wavelengths. It is said to be a high-density magnetic recording medium, and research and development has recently been carried out to solve various problems with the aim of putting it into practical use.

Among these, the most important problems are wear and running stability. This is especially true at times of high temperature and high humidity.

The magnetic recording medium is subjected to high-speed relative motion with the magnetic head during the process of recording and reproducing magnetic signals.

In this case, the vehicle must run smoothly and in a stable manner. Also, wear and damage due to contact with the magnetic head must not occur.

However, no ferromagnetic metal layer alone can withstand the harsh conditions during magnetic recording and reproduction, and for this reason various slippery layers are provided on the surface layer.

One of them is Langmu, ir-Blodgett.
Japanese Patent Publication No. 56-30609 discloses a method for forming a uniformly adsorbed film of saturated fatty acids and metal salts by a method. With this method, the abrasion resistance and lubricity are improved somewhat, but the
%RH), problems still remain regarding slipperiness and running durability. Moreover, from a manufacturing standpoint, it is extremely difficult to form a uniform adsorption layer on the surface of a long magnetic recording medium on an industrial scale.

On the other hand, there is a method in which an organic lubricant and a polymeric substance are laminated on a ferromagnetic vapor-deposited thin film by simultaneous vapor deposition (Japanese Patent Publication No. 56-723
No. 8) is disclosed. Although it is said that this method improves the slipperiness and film surface strength, the amount of lamination on the ferromagnetic vapor-deposited thin film of the organic lubricant and polymer material shown in the two examples is 400 and 470. Magnetic recording media have too large a spacing loss at short wavelengths, making them unsuitable for use at short wavelengths.

Object The object of the present invention is to provide a method for solving the above problem, namely at short wavelengths.

Structure of the invention Vacuum evaporation method, ion blating,
All ferromagnetic thin films are laminated using thin film forming means such as sputtering. Subsequently, in a vacuum evaporation apparatus, the ferromagnetic thin film surface is coated with at least fatty acid amide as a main component,
The amount of lamination per unit surface area of the ferromagnetic thin film is 10×1
0 ~ 100X10-86 ・.

C1l/cd] is laminated by a vacuum evaporation method.

In this case, if the magnetic recording medium is constructed with a lamination amount of 5XIC)-897d or less, no effect on lubricity will be observed even at normal temperature and normal humidity. Also, 500X10-817cd
In the above case, immediately after starting to use the vehicle, the vehicle runs smoothly, but as the number of runs increases, the running becomes unstable.

From the viewpoint of both abrasion resistance and runnability at high temperature and high humidity, the amount W of the slippery layer is further restricted to 10 x 10-8 to 100
Preferably, it is X10-811/d. In this case, the amount of lamination is determined by electromagnetic conversion characteristics (for example, among the organic lubricant layers laminated at wavelength This causes a larger spacing loss.

Assuming that the specific gravity of the laminated slippery layer is 1.degree. 1, the amount of lamination described above is converted into an average film thickness t, which corresponds to 6 meters and 10 to 100 people.

As a method for detecting the amount of the organic slippery layer during production, a film thickness monitor whose detector is made of quartz is used. Furthermore, the amount of organic matter actually adhered was measured gravimetrically using a microbalance, and it was confirmed that it roughly matched the layered amount W calculated by a film thickness monitor. ing.

The amount of lamination is controlled by controlling the temperature inside the evaporation source container, which is placed in the vacuum evaporation apparatus and filled with the organic lubricant.

The organic lubricant used in the present invention has at least a fatty acid amide as a main component, and also contains other components such as fatty acids, fatty acid esters, etc.

The ratio of the stacking amount of fatty acid and the stacking amount of fatty acid amide as an example of other components is preferably in the range of 0.1 to 1.

The same can be said about fatty acid esters.

When the organic lubricant layer is composed of multiple types of lubricants, a plurality of evaporation source containers are arranged in the vacuum evaporation apparatus, and each container is filled with one type of organic lubricant. It is necessary to completely control the temperature inside each evaporation source container so that the amount of stacked layers and the ratio of stacked layers described above can be obtained.

The fatty acid amide used as the main component in the present invention preferably has a fatty acid carbon number of 12 or more.

For example, lauric acid amide, myristic acid amide, palmitic acid amide, stearic acid amide.

Araxic acid amide, behenic acid amide, lignoceric acid amide, cerotic acid amide, montanic acid amide, melisic acid amide, n-todriacontanoic acid amide, n-tetratriacontanoic acid amide.

Examples include n-hexatriacontanoic acid amide and n-octatriacontanoic acid amide.

Fatty acid amides having 11 or fewer carbon atoms exhibit almost no slipperiness.

When a fatty acid is used as another component in the present invention, it preferably has 12 or more carbon atoms.

For example, lauric acid, myristic acid, palmitic acid, stearic acid, araxic acid, behenic acid.

Lignoceric acid, cerotic acid, montanic acid, melisic acid, n-todriacontanoic acid, n-tetratriacontanoic acid, n-hexatriacontanoic acid.

Examples include n-octatriacontanoic acid.

Fatty acids having 11 or fewer carbon atoms lack slipperiness stability. Further, when a fatty acid ester is used as another component used in the present invention, a monohydric or polyhydric alcohol ester of a fatty acid having 8 or more carbon atoms is used. When the number of carbon atoms in the fatty acid used in the fatty acid ester was 7 or less, little lubricity was observed.

The ferromagnetic thin film used in the present invention is made of Fe, Go, Ni or other ferromagnetic metals, or Fe-Co, Fe-N
i.

Co-Ni, Fe-Cu, Co-Cr, Co
-Ga, Co-Cu, Ni-Cu.

Ferromagnetic alloys such as Fe-Co-Ni and Mn-B1,
Fe-0,Co-Ni-〇Fe-Co-OFe
An oxide magnetic material such as -Co-Cu-0 is used.

Furthermore, the non-magnetic substrate used in the present invention is made of polycarbonate, polyethylene terephthalate,
It may be made of polyimide, glass, alumina, ceramics, sapphire, aluminum, or the like.

Description of Examples Example 1 Cobalt (80%) was deposited on a long film made of polyethylene terephthalate with a thickness of 10 μm in a vacuum evaporation apparatus 1 (not shown) by a vacuum evaporation method.
A ferromagnetic thin film layer was created by continuous oblique evaporation of nickel (20%) with forced introduction of oxygen. Subsequently, in a vacuum evaporation apparatus 2 schematically shown in FIG. 1 (exhaust system etc. are omitted), an organic slippery layer is laminated on the surface of the ferromagnetic thin film by vacuum evaporation. That is, the film 1 on which the ferromagnetic thin films are laminated is supplied from the unwinding roll section 2, and the surface of the ferromagnetic thin film 10 is covered with the benzene filled in the evaporation sources 3 and 4 set at a predetermined temperature. These evaporated molecules coming from the acid amide 3a and stearic acid 4a mix, and while the organic material layer consisting of behenic acid amide and stearic acid is laminated, the organic material slipping layer and the ferromagnetic material layer are stacked. A film 1 containing a thin film is wound around a take-up roll section 5. A method for detecting the stacking amount of each organic substance in the organic substance slipping layer is, for example, by detecting the stacking amount Wv of behenic acid amide.
An explanation will be given using the case as an example. A film thickness monitor is placed in the vicinity of the film 1 running from the unwinding reel 2 toward the take-up reel 1 in the figure, and in a position where only the molecules of behenic acid amide 3a flying from the evaporation source 3 can be detected. 3b, it is possible to detect the stacking amount WvQ of only behenic acid amide in the organic slipping layer. The shielding plate 6 arranged between the evaporation source 3 and the evaporation source 4 extremely reduces the amount of the evaporated molecules of stearic acid 4a filled in the evaporation source 4 that fly to the film thickness monitor 3b. It was arranged for this purpose.

Among the organic slipping layers, the amount W of stearic acid alone
Similarly, s can be detected by the film thickness monitor 4b.

Note that 7 in the figure indicates the winding 11 from the unwinding roll section 2.
2. Disposed near the film 1 running in the part 5,
7a shows a mask placed in order to control the amount of behenic acid amide 3a and stearic acid 4a molecules coming from evaporation sources 3 and 4 stacked on the surface of the ferromagnetic thin film; This shows the mask hole that has been opened, and most of the behenic acid amide and stearic acid molecules that have passed through the mask hole 7ai are deposited on the surface of the ferromagnetic thin film.

By the above method, a magnetic recording medium having the stacking amounts Wv and Ws'i of behenic acid amide and stearic acid as shown in Table 1 was manufactured, and then each magnetic recording medium was cut into 8 pieces, so that the sample flow was 1 ~ 6 magnetic tapes include magnetic tapes without an organic slippery layer (sample demand is ○) and 30
The dynamic friction coefficient was measured in a 90% RH environment, and the electromagnetic conversion characteristics were measured in an environment of room temperature and humidity using a testing machine with the same functionality as a commercially available VTR.

Example-2 On the surface of a ferromagnetic thin film prepared in the same manner as Example-1,
By filling the evaporation source 3 with stearic acid amide and the evaporation source 4 with tristearin and using the same method as in Example 1, an organic slippery layer consisting of behenic acid amide and tristearin, that is, Table 2 A magnetic recording medium having a laminated amount Wsa and WTf of stearic acid amide and tristearin as shown in FIG. The same measurements as in Example-1 were performed. Note that the magnetic tape used at this time without a square lubricating layer was subjected to the same measurements as the above-mentioned magnetic tape, with the sample &' being set at 100.

Tables 1 and 2 show the measurement results of the dynamic friction coefficient and electromagnetic conversion characteristics of the magnetic tape shown above.

All the measurement results of the coefficient of dynamic friction were measured in a constant temperature and humidity room at 30°C and 590%RH, and the diameter was 4.

A post made of 5US420■2 is installed, and a magnetic tape is wrapped around the post. A certain tension is applied to the magnetic tape, and the speed is 18 mm/s.
It is sent at a speed of ea. 13. -7 When the above magnetic tape 'i was run back and forth 100 times, the relationship between the number of reciprocations and the coefficient of kinetic friction was converted into data, and this shows the coefficient of kinetic friction at the first and 100th reciprocation. be.

In addition, the item "presence or absence of scratches" in Tables 1 and 2 is 100
This shows whether or not there were scratches on the surface of the ferromagnetic thin film of the magnetic tape after it was reciprocated several times.

The electromagnetic conversion characteristics were measured at a wavelength of 'io and 85 μm, and the output of each magnetic tape was compared, with the output of the magnetic tape on which no organic slipping layer was laminated as o (dB). ing.

Margin below 15.7 From Tables 1 and 2, it can be seen that the surface of the ferromagnetic thin film contains at least fatty acid amide as a main component, and the amount of lamination on the surface of the thin film is 10X10)-8 to 1o○X10-"9/ld.
A magnetic tape in which an organic slippery layer is laminated by a vacuum evaporation method has a stable dynamic friction coefficient, that is, running stability at high temperature and high humidity, and has no scratches on the surface of the ferromagnetic thin film. In other words, it can be seen that the abrasion resistance of the magnetic tape is improved.

Furthermore, it can be seen from the electromagnetic conversion characteristics that the amount of deterioration is extremely small. (As far as the video playback screen is concerned, it does not affect the image quality in any way.) In the above embodiments, all explanations are given using magnetic tape as an example, but the present invention is also fully effective for magnetic disks and magnetic cards. Needless to say, it brings.

Effects of the Invention According to the present invention, it is possible to easily obtain a magnetic recording medium that is excellent in wear resistance, runnability, and has excellent electromagnetic conversion characteristics at short wavelengths.

BRIEF DESCRIPTION OF THE DRAWINGS The 167-zoo diagram is a diagram for explaining the method of manufacturing a magnetic recording medium according to the present invention.

Claims (1)

[Claims] (1) An organic slippery layer is laminated on a ferromagnetic thin film provided on a non-magnetic substrate, and the organic slippery layer contains at least a small amount of fatty acid amide as a main component and is a unit of the ferromagnetic thin film surface. The amount of lamination per area is 10X10 ~ 1ωX10 11/
A magnetic recording medium characterized by being d. (→ A ferromagnetic thin film is provided on a non-magnetic substrate, and then an organic slippery layer containing at least fatty acid amide as a main component is deposited on the ferromagnetic thin film by vacuum evaporation in an amount per unit area of the ferromagnetic thin film surface. Lamination amount is 1o x 10-8 ~ 100 x 10
A method for manufacturing a magnetic recording medium, characterized by stacking layers so that g/d.