JPS63106925A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve a weather resistant characteristic and preserving stability by preparing a rolled and vapor deposited article under specific roll-up tension, then un-rolling the vapor deposited article and preserving the same in an oxidation accelerating atmosphere at the time of providing a thin magnetic metal or alloy film by a roll-up vapor deposition method on a flexible substrate. CONSTITUTION:The rolled and vapor deposited article is prepd. under >=13.5X10<8>b/tkg weight roll-up tension when the width of the flexible substrate is designated as bmm and the thickness thereof as tmm at the time of providing the thin magnetic metal or alloy film by the roll-up vapor deposition method on the flexible substrate. The rolled and vapor deposited article is thereafter un-rolled under <=13.5X10<-8>b/tkg weight roll-up tension. The vapor deposited article which is un-rolled in such a manner is preserved for a specified period or longer in the oxidation accelerating atmosphere. The specified period varies with the roll-up tension and is preferably >=12hr. The oxidation accelerating atmosphere refers to the inside of a gas contg. an oxidative gas such as oxygen and ozone and may be; for example, in the atm. air. An atmosphere contg. the pressurized oxidative gas is equally satisfactory.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a magnetic recording medium, and more particularly to a method for manufacturing a metal thin film type magnetic recording medium with excellent weather resistance.

[Conventional technology]

What has been conventionally used as a magnetic recording medium is a so-called one-coating type magnetic recording medium in which powdered magnetic powder is coated on a non-magnetic substrate together with an organic binder and dried. On the other hand, with the increasing demand for high-density recording in recent years, expectations for so-called ``metal thin film type magnetic recording media'' have increased, and steady development and research is being carried out.

Although the above-mentioned "metal thin-film type magnetic recording media have greater potential than conventional coating-type magnetic recording media in terms of electromagnetic conversion characteristics and recording density, their fateful weakness is that they have poor weather resistance." For example, so-called vapor-deposited tape, which is made by obliquely vapor-depositing cobalt on a polyester film, will rust if left in an atmosphere of 60% and 20% RH for about a week, and will clog the head if recorded and played back on a deck. This rust will progress even further if a small amount of Na (J) microcrystals is introduced in the form of a sol into this atmosphere, or if sulfur dioxide gas of about /ppm is introduced. Furthermore, if the metal film is left in a high-temperature, high-humidity atmosphere, oxidation of the metal film progresses and the total amount of magnetic flux increases by more than 10%.

This problem of poor weather resistance of metal thin film media is widely recognized, and various methods have been proposed to improve the weather resistance. However, the effect cannot be said to be sufficient.

Alternatively, there are problems such as requiring large-scale equipment and poor productivity, or sacrificing other characteristics such as electromagnetic conversion characteristics.Therefore, it is desirable to improve weather resistance characteristics, which is simpler and more effective. It was rare.

[Purpose of the invention]

The present invention was made in view of the above circumstances, and its purpose is to provide a method for manufacturing a magnetic recording medium with improved weather resistance and storage stability.

[Structure of the invention]

In the present invention, when a magnetic metal or alloy thin film is provided on a flexible substrate by a winding vapor deposition method, the width of the flexible substrate is reduced to bmm.
, when the thickness is tmm13. ! ×1010-8b-Magnetic recording characterized in that the above-described rolled vapor-deposited product is re-wound with a winding tension of at least 100 lbs., and then the above-mentioned rolled vapor-deposited product is re-wound with a winding tension of less than 100 lbs., and stored in an oxidizing acceleration atmosphere. The present invention relates to a method for producing a medium.

The flexible substrate of the present invention is mainly a plastic substrate such as polyethylene terephthalate, polyimide, polyamide, polyvinyl chloride, cellulose triacetate, polycaponate, polyethylene naphthalate, or the like.

The magnetic metals and alloys of the present invention include metals such as Fe, Co, and Ni, or Fe-Co and Fe-Ni.

Co-Ni, Fe-Co-Ni, Fe-Rh.

Co-Cu, Co-Pr, Co-8m, Co-t, Ni
-Cu, Co-Cr, Fe-Cr, Ni-Cr, etc. Magnetic metals and alloys formed in the form of a thin film on a substrate are often partially oxidized and/or nitrided to impart more desirable characteristics. Particularly preferred is co or C.

It is an alloy containing 70Hi% or more of.

An example of a winding vapor deposition apparatus is shown in FIG. When using this apparatus, a rolled vapor-deposited product is prepared as follows. That is,
The flexible substrate 7 is sent out from the delivery roll 6, moved along the cooling drum ta, and wound up on the take-up roll ta. Vapor deposition takes place in this quantum type 3. 1st
What is shown in the figure is a method of forming a magnetic film by a so-called oblique evaporation method, in which film formation is performed while partially regulating the incident vapor flow using a mask lλ. Also, gas inlet/
It is also possible to use known methods such as controlling the magnetic properties by introducing an oxidizing gas or the like. In the apparatus shown in FIG. 1, the winding tension of the present invention can be set by controlling the tension when winding around the winding roll ta. It is desirable that the winding tension is equal to or greater than the width of the flexible substrate.

The upper limit is not particularly stipulated, but for example, i o -6-
If the weight exceeds 1 kg, the plastic substrate may be deformed, which is not preferable.

Sara<, t3. If the width is less than 4W and the width of the substrate is 300 mm or more, wrinkles are likely to occur due to the parallelism of the rollers, etc., and this will also affect the tension of the cooling drum and the delivery roll. This may also be related, but the substrate may not be cooled sufficiently and may receive a large amount of radiant heat from the high-temperature crucible 1O, resulting in severe thermal damage to the substrate. All of these are undesirable as they reduce the yield.

The thus obtained rolled vapor-deposited product is taken out from the vapor deposition apparatus, rewound, and subjected to preservation treatment. That is, when the width of the flexible substrate is t) mm and the thickness is tmm, the winding tension is 13. This is undesirable because there is a risk that the zxtO-8 roll will lose its shape. The atmosphere in which this rewinding is performed is normal air.

The rolled vapor-deposited product thus rewound is stored in an atmosphere that accelerates oxidation for a certain period of time. Here, the certain period of time varies depending on the film width and winding tension, but is preferably 72 hours or more. The oxidation acceleration atmosphere refers to a gas containing an oxidizing gas such as oxygen or ozone, and may be, for example, the atmosphere. Alternatively, a pressurized oxidizing gas-containing atmosphere may be used.

〔Example〕

Using the vapor deposition apparatus shown in Fig. 1, Cog
o Ni 20 (atom%) was deposited to form a magnetic thin film. The substrate used had a film width of toomm and a total length of 1room. Conveying speed rm/min, incident angle 0m1n=
Ko! 0, film thickness is 2000X, and 02 gas is introduced from the gas inlet // in the vacuum chamber of the evaporation chamber is J, 0x10 To
Vapor deposition was performed while introducing the material so that the relationship was rr.

At this time, the winding tension was set to j kg, and three rolled vapor-deposited products were created under these conditions. One of these is in the atmosphere at normal temperature and humidity! It was left as it was for several days.

(This is called the sample A) Also, one is the winding tension /, 7
It was re-wound with jkgW and left for the same j days (Sample B). Another one was re-wound at a winding tension of lkp and left for j days (sample C).

From the three samples obtained in this way, μ
Book sample / OFFI / m x 7! ? Fl
/ I cut it out to the size of m (Ko l ~ Ko da, Otsu l ~ Otsu μ
, Hei l ~ Hei ≠. The smaller number corresponds to the center side of the winding) or more/λ samples to 0%
Total magnetic flux φm before and after leaving it in RH atmosphere for one week
The rate of change of (M x / Crn) - Δφm/φm was measured. The results are shown in the table below (values are %). The smaller the value of this rate of change -Δφm/φm, the better the weather resistance. Sample B is slightly better than A, but sample C shows almost the same low values over the entire length of the roll, clearly showing the effect of improved weather resistance.

〔Effect of the invention〕

As described above, by using the method of the present invention, metal thin film magnetic recording media with excellent weather resistance and storage stability can be easily and uniformly produced.

[Brief explanation of the drawing]

FIG. 1 shows a winding vapor deposition apparatus. l...Vacuum tank t...Feeding roller...Cooling drum 10...Evaporation source/I...Gas inlet lμ-Take-up roller Patent applicant Fuji Photo Film Co., Ltd. Procedure correction band 1972 72-Monday 1st, Incident Display 1986 Patent Application No. 1! 2t4A
r No. 2, title of invention: method for manufacturing magnetic recording medium 3,
Relationship with the case of the person making the amendment Patent applicant 4, subject of the amendment [Claims J column and “Detailed Description of the Invention” column 5, Contents of the amendment L) of the specification] Correct the "Range of" column as shown in the attached sheet. e) Correct "to tori o scratch" on page λ, line 13 of the specification to "to0 cyo". 3) Correct “wo 關” on page 3, line 1 of the same book to f” tmJ. 4I-) Correct “wo fin” on page !/line j of the circular to rtff! Correct it with J. ! ``O cod'' on page 73 of the same book is corrected to (-tmJ).
! 1tl- When the width of the flexible substrate is bw and the thickness is tm / J, j /J, zxlo-8uK A method for manufacturing a magnetic recording medium, characterized in that the deposited product is rewound at a winding tension of less than 4 times and stored in an oxidizing acceleration atmosphere.

Claims (1)

[Claims] (1) When providing a magnetic metal or alloy thin film on a flexible substrate by the winding vapor deposition method, when the width of the flexible substrate is bmm and the thickness is tmm, ¥13.5 x 10^-^8b/ A rolled vapor-deposited product is created with a winding tension of ¥13.5 x 10^-^8b/tkg weight or less to accelerate oxidation. A method for manufacturing a magnetic recording medium, characterized by storing it in an atmosphere.