JPS60125918A - Magnetic recording medium and its production - Google Patents

Abstract

PURPOSE:To improve wear resistance, traveling stability and high reliability of recording and reproduction by constituting a specific fluoride on the surface of a thin ferromagnetic metallic film. CONSTITUTION:A lubricant layer 3 constituted on the surface of a thin ferromagnetic metallic film 2 constituted on the surface of a nonmagnetic base 1 contains 2 kinds of lubricants consisting of low mol. wt. polyolefin 3b and fluoride 3a expressed by CnF2n+1COOH or CnF2n+1COOM. At least the fluoride 3a of the layer 3 is constituted on the surface of the film 2. The magnetic recording medium provided with the lubricant layer contg. such fluoride on the surface of the film 2 has improved stability of running and wear resistance and has high reliability in recording and reproduction.

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention is applicable to magnetic recording devices such as audio chip recorders, video tape recorders, and PCM recorders.
Among magnetic recording media used in terminal data processing devices such as large-scale computers and partial computers, non-binder-type AA recording media whose magnetic layer is composed of a ferromagnetic metal thin film and their manufacturing capabilities are especially useful. Regarding leaving.

Conventional configurations and their problems Non-magnetic substrates, magnetic layers, vacuum evaporation, suba, tarinog,
Non-inder type magnetic recording media, which are composed only of ferromagnetic metal thin films by making full use of thin film formation methods such as ion/brating, and do not contain any additives, are It is said to be a high-density recording medium with excellent conversion characteristics, 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 problem is that recording and playback must be performed while ensuring wear and running stability.

A magnetic recording medium is placed under high-speed relative motion with a magnetic head during the recording and re/IE process of magnetic signals.

At that time, the process must be carried out smoothly and stably. Father, wear and tear (11) due to contact with the magnetic head must not occur.

However, my father told me that there is no ferromagnetic metal/II7 film layer that can withstand the harsh conditions of magnetic recording and birth, so I decided to add a divine lubricant layer to the edge of the surface.
IJl has been said.

As a way to deal with the problem described in J-, perfluoroargylcarboxylic acid CnF2n is added to the surface of the ferromagnetic metal thin film.
4-1C○○H or its metal salt CnF2□-1C
It has been proposed to form a fluoride represented by OOM. Note that n represents an integer, and 4 represents a metal element.

Although this proposal greatly improves the wear and running stability of the ferromagnetic metal thin film, there is a phenomenon in which the reproduced signal is missing within a given deck (sometimes referred to as blindness for short).

) occurs, resulting in the problem of a lack of high reliability in recording and playback.

We are currently investigating the cause of this, but it appears that CnF2n detached from the surface of the ferromagnetic metal thin film for some reason.
It is presumed that this occurs because +1COOH or CnF2n+1000M adheres near gap E1 of the magnetic head.

Purpose of the Invention The present invention solves the problems of the lubricant layer containing fluoride described above, and improves wear resistance, running stability, and recordability.
The present invention provides a magnetic recording medium with high reliability over a lifetime and a method for manufacturing the same.

Structure of the Invention The magnetic recording medium of the present invention includes 1 a non-magnetic support, a ferromagnetic metal thin film formed on the surface of the non-magnetic support, a low molecular weight polyolefin formed on the surface of the ferromagnetic metal thin film, and CnF2n+, C0OH or C": CnF2n
+1COOM (a metal salt of CnF2n+1COOH. By being constructed on the surface of a thin metal film, it is possible to prevent wear and tear [behavioral quality and high reliability of recording].

Historically, the method for manufacturing a magnetic recording medium of the present invention includes a step of laminating a ferromagnetic metal thin film on a non-magnetic support, and a wet method to coat the surface of the ferromagnetic metal thin film with CnF2□-1COO.
Step of applying a fluoride consisting of H or CnF2n+1000M and the surface of the fluoride] Either or both of nj and the surface of the ferromagnetic metal thin film not coated with the fluoride are coated by a dry method. Therefore, the method includes a step of laminating low-molecular-weight polyolefin, and can effectively form a magnetic recording medium with the above-described effects.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the magnetic recording medium according to the present invention will be described with reference to FIG. It is a diagram.

In FIG. 1, 1 represents a non-magnetic support, 2 represents a ferromagnetic metal thin film formed on the surface of the non-magnetic support 1, and 3 represents a ferromagnetic metal thin film formed on the surface of the ferromagnetic metal thin film 2. is low molecular weight h1-polyolefin 3b and CnF2n+1COO
This shows a lubricant layer containing two types of lubricants made of fluoride 3a represented by H or CnF2n+1000M, and in the lubricant layer 3, the fluoride 3a is
It is formed at least on the surface of the ferromagnetic metal thin film 2. In addition, in FIG. 1, the ferromagnetic metal thin film 20 has the above-mentioned 7 layers forming a substantially continuous layer rather than an island shape on the surface.
The low molecular weight polyolefin 3b has a continuous layer on the surface of the compound 3a.

CnF2n+1COOH or ll used in the present invention
-1Cnb -1- is desirable. Here, if n is less than 7, no effect as a lubricant will be found.

Preferably, it is a metal element such as MijMg, Ni, Co, Zn, or fla.

The low molecular weight polyolefin used in the present invention is low molecular weight polyethylene with a molecular weight of 10,000 or less.

Low molecular weight: i, polypropylene, low molecular weight polybutylene, etc., but the power of low molecular weight polyethylene and low molecular weight polypropylene is terrifying. Q has a lubricant layer containing low molecular weight 14-polybutyreno, which lacks long-term running stability. If you choose the subtotal average molecule (,1) that shows the distribution of molecular groups, it is likely to be 5 or more -F.A lubricant containing a low molecular weight polyolefin that is 5 or more -1-. In the layer, the car shows smooth running on the inner ridge where it starts running within the predetermined running system, but as the running turns J'W JJII, the running 11 becomes unstable.

Low molecule - 1: As a specific example of polyethylene, for example, Zanowanox 171-P (1500
), E-250P (2000), E-:300 (2000), Ill-P (2000), 1
31-P (3500).

161-P (5000), 161 (5000)
, i66-P(6000), and the like.

Note that the value in parentheses indicates the average numerator.

Specific examples of low molecular weight polypropylene include Viscol 660P (3opo) manufactured by Sanyo Chemical Industries, Ltd.
Examples include T'S-200 (3500) and 550P (4000). Note that the value in parentheses indicates the average molecular weight.

” The total amount of lamination WT on the ferromagnetic metal thin film 2 of the lubricant layer 3 consisting of two components is 10×10 to 100ox1.
0-8C! /cni] Good size, 50X10”~5o
ox 1o-8 [y/cri]. If the abundance is less than 100x1o-8Cy/crl, wear resistance cannot be obtained;
Above y), spacing loss due to the lubricant layer occurs.

Among the total lamination amount WT, low molecular weight polyolefin 3a
Assuming that the amount of stacking is WL and the amount of stacking of the above-mentioned horn compound 3o is wF, then NT-wL+WF is formed.
The ratio VVL/V'l'F is 0.05 or more, preferably 0.1 or more -42. WL/QF value is 0.0
If it is less than 5, scratches will occur during travel within a predetermined deck, resulting in a lack of high reliability in recording and reproduction.

The ferromagnetic metal thin film according to the present invention can be made of Fe, Co, Ni or other ferromagnetic metals, or Fe-Co, Fe-Ni.
.

Co-Ni, Fe-Cu, co-Cr, Co
-da, Co-Cu.

Ni-Cu, Fe-Co-Ni, mn-B1
ferromagnetic alloys such as

Fe-0, Co-rJi-0, Fe-Co-0, Fe-
A 4iθ material containing oxygen such as Co-Cu-0 thread is used.

If necessary, prior to the formation of the ferromagnetic metal thin film, a thin film with a DH effect, such as L' i , C
r, gold 1 such as Ni (or oxygen-mediated metal thin film, At
After forming an oxide thin film such as 203°SiO2,
A strong+a+l+ metal thin film as described in AiJ may be constructed.

The non-magnetic support used in the present invention (Arch 1, polyethylene terestalate or its copolymer, mixture).

A polyester film made of polyethylene naphthalate or a copolymer thereof, a mixture thereof, a polyimide film such as polyesterimide, polyimide, etc.

A typical example is a plastic film made of aromatic polyamide film or the like. It may be an inorganic material such as copper, crow, alumina, ceramics, zaphire, or aluminum.

2 to 4 show other embodiments of the magnetic recording medium according to the present invention. In the figure, 11, 12, 13 indicate non-magnetic supports, and 21, 22, 23 constituted on the surface of the non-magnetic supports 11, 12, 13 indicate ferromagnetic metal thin films,
Numerals 31, 32 and 33 formed on the surface of the ferromagnetic metal thin film 21, 22 and 23 indicate a lubricant layer. Furthermore, in FIG. 2, a low-molecular-weight compound 7] compound s1a, which constitutes a substantially continuous layer rather than an island-like layer on the surface of the ferromagnetic metal thin film 21, and an island-like low molecular weight compound 31a on the surface of the ferromagnetic metal thin film 21, are shown. polyolefin 3
The lubricant layer 31 is constituted by 11). In FIG. 3, there is a fluoride 32a in the shape of a dot on the surface of the ferromagnetic metal thin film 22, and the surface of the fluoride 32a and the ferromagnetic metal thin film 22 which is not coated with the fluoride 32a are shown. The lubricant layer 32 is made of a low molecular weight polyolefin 32b which is generally continuous on the surface.

In FIG. 4, a table of a heptadide 33a, which has an island shape on the surface of the ferromagnetic metal thin film 23, and its fluoride 33a (
The lubricant layer 33 is constituted by the low molecular weight polyolefin 33D having an island shape on the surface of the ferromagnetic metal thin film 23 which is not coated with the fluoride 33a.

Next, a method for manufacturing a magnetic recording medium according to the present invention will be explained. In the ia magnetic recording medium manufacturing method of the present invention, 1.
Non-linear 1t1. A stingray 9 forming a ferromagnetic metal thin film 2 on the support 1 and on the surface of the ferromagnetic metal thin film 2? !
,,! Civil law nF2n+1COQH or Cn in formula law
Apply a fluoride 3a consisting of F2 The soft method refers to a method used in addition to the wet method. The wet method is acetone, l-luene, methylethyl')-1-one, 7
A facial cloth liquid prepared by dissolving a specified lubricant in a solvent such as /l/coal is applied to the surface of a ferromagnetic metal thin film by a reverse roll method or a rod coating method, and then the solvent is coated with a dry ray♀. In this method, the lubricant is left on the surface of the ferromagnetic metal thin film by evaporating the lubricant.

The dry method is a method in which a lubricant is directly formed on the surface of a ferromagnetic metal thin film without using the solvent, and a lubricant is efficiently and effectively formed on the surface of the ferromagnetic metal thin film. Therefore, it is mainly carried out in a vacuum apparatus using thin film forming means such as ion blating, vacuum evaporation, snowdropping, and plasma polymerization.

In the case of a dry method such as ion blasting, sputtering, or plasma polymerization, it has the effect of forcibly removing the fluoride already formed on the surface of a ferromagnetic metal thin film. It depends on the selection of the conditions when applying the coating, such as strength, degree of vacuum 2, etc., and the amount of fluoride to be coated, taking into account the amount of fluoride that will be forcibly detached from the thin film. What is solved? In the case of the nine-space deposition method, the above-mentioned problem of separation is not noticeable.

Next, in the method for manufacturing a magnetic recording medium of the present invention, a low molecular weight polyolefin is laminated by a dry method on either or both of the surface of the heptadide and the surface of the ferromagnetic metal thin film not coated with fluoride. An embodiment of a vacuum evaporation apparatus applied to the step of forming the wafer is explained below with reference to FIG.

As shown in FIG. 5, a magnetic recording medium 4 in which a strong 71θ metal thin film 2 is formed on a long and wide non-magnetic support.
iJ1, delivery L provided in the vacuum vapor deposition device 6
Jl+ 6 When being wound onto the winding shaft 8 through the running system 7 consisting of free rollers, expander rollers, proximity rollers, comb rollers, etc., the film is disposed in the vacuum vapor deposition device 5 and filled with polyolefin. J) The evaporated particles of low molecular weight polyolenoin and the evaporated fraction 1'-9a flying from the evaporator #9 set at a predetermined temperature are laminated on the surface of the ferromagnetic metal thin film 2. ,
9 and the magnetic recording medium 4 which is in the transport state VC.
A mask 10 having a perforated portion 10a is provided,
Evaporated particles and evaporated molecules 9a flying from the evaporation source 9
4 and 11 indicate gloss placed between the evaporation source 9 and the mask 1Q, and the evaporated particles and evaporated molecules 9a are laminated on the magnetic recording medium 4. Cover the opening 10a when the opening 10a is not exposed to the lamination +I-1 layer 41: l/x Irr +, -1-1-
IM r-+ +r17 A' t-i -j Alr
J- is also arousing. Although not shown in the figure, a monitor on the crystal film 11 is placed near the opening 10a in order to detect the amount of the evaporated particles and molecules 9a stacked on the magnetic recording medium 4. It is arranged.

Incidentally, the inventors selected methanol as the solvent,
C9F19CQOH with n=9 was dissolved in the solvent (1W) and coated on the surface of the ferromagnetic metal thin film by a wet method for 1J. After that, it was partially dissolved in heated toluene. This low molecular weight polyethylene was applied by a wet method to the surface of the magnetic metal thin film which was not coated with the compound described above and the fluoride. Furthermore, since the lubricant is applied in a discontinuously aggregated state, it has been impossible to form a uniform lubricant layer on the surface -L of a long magnetic recording medium.

More specific examples of the present invention will be described below.

Example-1 Polyethylene terephthalate mold l-V with encroachment and thickness of 10 μm Ikushina Zenhai V bale, ICo' (80%)
-Continuous diagonal deposition of Ni (20%) was performed with forced oxygen supply by four people to form a ferromagnetic metal thin film (thickness 1600A) with Ft
= r&shi/to.

On the surface of this Jf+i magnetic 1/1 metal film, a coating film having the above composition was applied using a 1-" throat coating method. 1
1st WF is %vF=60X 10-8 [y/Cnj]
Met.

Subsequently, Sunwax 171P (manufactured by Sanyo Chemical Co., Ltd.) as a low molecular weight polyethylene was laminated on the surface of the straight metal thin film coated with AiJ fluoride in a vacuum apparatus. The stacking amount WL of leaf wax 1F 1P is 30X 10"7/crl)
/Hi.

Thereafter, the above-mentioned Mi magnetic recording medium was cut into pieces having a width of 8 mm to obtain a sample shape of a magnetic tape.

Coefficient of kinetic friction of magnetic tape with lubricant layer provided in this way/
IS and the electromagnetic conversion characteristics under the specified wavelength at 26℃,
Measured under an environment of 60% Ri.

Jitsukai Q1//Li-2 A coating liquid 11 having the following composition was applied to the surface of a 74 ferromagnetic metal thin film prepared in the same manner as in Example 1 by a reverse roll method. At this time, the fluoride stack t WF
was 100 x 10-8 [710f] 0 Next, in the same way as in Example 1, a low molecule was applied to the surface of the ferromagnetic metal thin film coated with the fluoride by vacuum evaporation. Viscol 660P (manufactured by Sanyo Chemical Co., Ltd.) as polypropylene was laminated.

At this time, the number of laminated layers WL of Viscoel 660P is 6o x 1
O-8Cjl/cni].

Thereafter, the above magnetic recording medium was cut into 8 cylinder widths to form a sample shape of magnetic tape 2, and the measurements described in Example 1 were carried out.

Example 3 A coating solution ■ having the following composition was applied to a ferromagnetic metal thin film prepared in the same manner as in Example 1 using a reverse roll method.
It was applied. At this time, the fluoride (7) 4 blue layer i-,
wFu, 100 x 10-8Cy/crl:]7. Ta.

Methanol 20QOy Subsequently, in the same manner as in Example C-1, Sunwax 171P as a low-fraction Xf-plated polyethylene was laminated on the surface of the fluoride-containing ferromagnetic metal thin film by vacuum evaporation. Sunwax 171P (7) stacking amount Vv at this time
L was 40 x 10-8 (7/cnVJ).

Thereafter, the above magnetic recording medium was cut into a width of 8 mm to obtain a sample shape of magnetic tape 3, and the measurements described in Example 1 were carried out.

Example 4 A coating solution (2) having the composition shown in (1) was applied onto a ferromagnetic metal thin film prepared in the same manner as in Example (1) by the rod coating method. The stacking amount WF of the fluoride at this time
is 1o ox 1O-8 (,S''/ari).

Methanol 200OS! Next, in a vacuum apparatus, sunwax 131P as low molecular weight polyethylene was evaporated on the surface of the ferromagnetic metal thin film coated with the 111 fluoride using the vacuum evaporation method in the same manner as in Example-1. Laminated. ) This laminate iii WL kj, 30 X 10-” jl
-/aJ.

Thereafter, the magnetic recording medium No. 1 was cut to a width of 8 mm, and the measurements described in Example 1 were performed using the sample shape as a magnetic tape No. 4.

Comparative Example-1 Coating liquid I used in Example-1 was applied to the surface of a ferromagnetic metal thin film prepared in the same manner as in Example-1 by a rod coating method.

Thereafter, the magnetic recording medium was cut into bun width samples to obtain magnetic tapes having a sample shape of 5. Then, measurements similar to those for the sample shape described above were performed.

Comparative Example 2 A ferromagnetic metal thin film prepared in the same manner as in Actual Mli Example 1 was cut into an 8H width without applying anything to make a sample thread No. 6 magnetic tape. Then, measurements similar to those for the sample measurement described above were performed.

Sample types 1 to 1 obtained in the above-mentioned actual Mi examples and comparative examples; l'; 1. The measurement results of the flow line coefficient and electromagnetic conversion characteristics of the s6 magnetic tape are listed in Table 1.

The measurement of the dynamic friction coefficient is performed as follows.

The magnetic tape of each trial was wound around a post having a diameter of 4ψ and a material of 5US42°2, and the magnetic tape was run at a speed of IBmm/sec while applying a constant tension.

The length of the magnetic tape used to measure the coefficient of dynamic friction was 10 m. This involves selecting an arbitrary position in the longitudinal direction from a long magnetic tape, and cutting it into magnetic tapes with a length of 10 m from the selected position.
There is a measurement item-C.

Note that when many selected positions are extracted and the behavior of the dynamic friction coefficient in the longitudinal direction is examined, the values generally match the values shown in Table 1. Therefore, the magnetic recording medium of the present invention has extremely little variation in the coefficient of dynamic friction in the longitudinal direction.

Table 1 shows the coefficient of kinetic friction for the first and 100th reciprocation of the data obtained by running the magnetic tape of each sample 100 times back and forth and the relationship between the number of reciprocations and the coefficient of kinetic friction. . Furthermore, the presence or absence of scratches on the table is 1.
This figure shows whether there were any scratches on the surface of the ferromagnetic metal thin film of the magnetic tape after 00 reciprocating runs.

Next, we will describe the measurement of electromagnetic conversion locality. The magnetic tape of each sample has the same function as a commercially available VHS video tape /ζ
Light measurements were taken by running the vehicle inside the test track. A wavelength of 0.85 (μm) was selected, and one of the two heads in the /linder was used as a recording head and the other as a reproducing head, and recording and reproduction were performed continuously. The scale in the table is -16 (d) from the average playback level.
B) shows the total dropout time of the reproduced signal exhibiting the above output down.

Incidentally, the time used for optical measurement was 100 hours for all samples.

Margin Table 1 Table 1 shows that the magnetic tapes of Samples 161 to 4, which are examples of the present invention, have good lubricity because the initial coefficient of kinetic friction during reciprocating running is on the order of 0.2 to 0.3. That's what comes to mind. The coefficient of dynamic friction after 100 cycles of reciprocating travel has little variation compared to the initial value.
It can be seen that the running stability is good. Roughly speaking, it can be seen that the wear resistance is good because there are no scratches after 100 reciprocating runs. In addition, the total missing time of eyelids, which exhibit electromagnetic conversion characteristics at short wavelengths, is considerably shorter than that of Sample Type 5 and Sample Type 6 presented as comparative examples, resulting in high reliability of recording and playback. It can be seen that it has

In this example, the effects were specifically shown for several types of samples, but it was confirmed that the combinations of the other advantages mentioned above constituting the present invention also had similar effects.

Further, in this embodiment, a magnetic tape is used as an example of the magnetic recording medium, but it may also take the form of a magnetic disk or a magnetic disk without departing from the gist of the present invention.

Effects of the invention Low molecular weight polyolefin and CnF2n+1CoOH are added to the surface of the ferromagnetic metal thin film. It can be seen that the electromagnetic conversion characteristics have been improved to a certain extent, that is, high reliability in recording and reproduction is achieved.

Moreover, the surface of the ferromagnetic metal thin film and CnF2n, -1COOH
Alternatively, the method for producing a magnetic recording medium of the present invention involves laminating a low molecular weight ivoryolefin on one or both of the dowels on the surface of a fluoride made of CnF2n (1000M) by a dry method. The lubricant layer can be uniformly deposited, and an effective lubricant layer can be formed on an industrial scale.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the basic structure of a magnetic recording medium according to the present invention, FIGS. 2 to 4 are cross-sectional views showing other embodiments of the magnetic recording medium according to the present invention, and FIG. 6 is a cross-sectional view showing the basic structure of a magnetic recording medium according to the present invention. 1 is a configuration diagram showing an embodiment of a vacuum evaporation apparatus applied to the method of manufacturing a magnetic recording medium of FIG. 1, jl, 12.13...Nonmagnetic support,
2゜21.22.23...Ferromagnetic metal thin film, 3,3
1゜32, 33...Lubricant layer, 3a, 31
a, 32a, 33a...Fluoride, 3
D, 31b, 32b, 33b...low molecular weight polyolefin. Name of agent: Patent attorney Toshi Nakao and 1 other editors
1 Figure,? h Figure 5

Claims (2)

[Claims] (1) A nonmagnetic support, a ferromagnetic metal thin film formed on the surface of the nonmagnetic support, and a low molecular weight polyolefin and CnF2rl+1COOH on the surface of the ferromagnetic metal thin film.
or a lubricant layer containing a heptadide represented by CnF2n+1COOM (n: integer 2M=metal element). (2) A step of laminating a ferromagnetic metal thin film on a non-magnetic support, and applying 7;1-CnF2n4-1COOH or CnF2n+1cO to the surface of the ferromagnetic metal thin film according to the Civil Code.
A process of applying a fluoride consisting of OM, and applying a low molecular weight polyolefin by a dry method to either or both the surface of the fluoride and the surface of the ferromagnetic metal thin film not coated with the fluoride. 1. A method for manufacturing a magnetic recording medium, comprising the step of laminating layers.