JPS61216112A - Magnetic recording medium and its production - Google Patents

Abstract

PURPOSE:To control sufficiently the corrosion of a magnetic recording medium from its side surface by coating a protective agent on the part adjacent to the protrusion on a substrate film and further coating a ferromagnetic metallic thin film layer thereon. CONSTITUTION:A protective agent 9 is coated on the part adjacent to a protrusion 41 of a substrate film 4 having ruggedness and the void to be formed adjacent to the protrusion 41 is filled with the protective agent 9. When a ferromagnetic metallic thin film 16 is formed thereon, the void to be formed adjacent to the protrusion 41 due to the shadow effect characteristic of the oblique- incidence vapor deposition is filled with the protective agent 9. Since the ferromagnetic metallic thin film layer 16 is formed under such conditions, the ferromagnetic metallic thin film layer is formed without generating any voids due to the shadow effect characteristic of the oblique-incidence vapor deposition, the corrosion of the magnetic recording medium from its side surface can be sufficiently controlled, the strength of the lower part of the ferromagnetic metallic thin film layer is enhanced and sufficient durability can be obtained even when the medium is traveled for a long time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a magnetic recording medium having a ferromagnetic metal thin film layer as a recording layer and a method for manufacturing the same, and more specifically to a magnetic recording medium having a ferromagnetic metal thin film layer as a recording layer, and more specifically to a magnetic recording medium having a ferromagnetic metal thin film layer as a recording layer, and more specifically to a magnetic recording medium having a ferromagnetic metal thin film layer as a recording layer, and more particularly to a magnetic recording medium having a ferromagnetic metal thin film layer as a recording layer and a method for manufacturing the same. The present invention relates to a magnetic recording medium and its manufacturing method.

[Conventional technology]

A magnetic recording medium with a ferromagnetic metal thin film layer as a recording layer is produced by moving a base film such as Tsutomi or polyester film along the circumferential side of a cylindrical can in a vacuum atmosphere, and then depositing metal or other metals on this base film. It is made using methods such as oblique incidence evaporation of alloys, etc., and in recent years, it has become particularly popular for its high-temperature and high-humidity capacity.

In order to improve running performance under air, it is possible to use a base film having protrusions and further provide a wetting agent layer on top of the ferromagnetic metal thin film layer formed on the base film having protrusions. Proposed.

(Unexamined Japanese Patent Publication No. 59-94227) [Problems to be Solved by the Invention] However, in the method of using a base film having such protrusions and forming a ferromagnetic metal thin film layer on this base film, the ferromagnetic material Sha 1, which is unique to oblique incidence evaporation of
- As a result, voids are created adjacent to the protrusions of the base film, making it impossible to sufficiently suppress corrosion from the sides of the magnetic recording medium, resulting in insufficient durability when running for a long time. The problem was that I couldn't get it.

[Failure to solve the problem]

This invention was made as a result of various inspections to eliminate these drawbacks, and involves moving a base film having protrusions along the circumferential side of a cylindrical can in a vacuum atmosphere.
A vapor flow obtained by heating and evaporating the protective agent is applied to this base film at a high incidence angle to deposit the protective agent on the portions of the base film adjacent to the projections, and then the base film is shaped into a cylindrical shape. The protective agent is deposited along the circumferential surface of the base film, which moves in the opposite direction to the case where the protective agent is deposited along the circumferential surface of the projection.Secondly, the ferromagnetic material is heated and evaporated. By performing oblique incidence vapor deposition with a vapor flow of ferromagnetic material, the voids created adjacent to the protrusions of the base film due to the shadow effect during oblique incidence deposition of the ferromagnetic material are filled with a protective agent in advance, and the voids are filled with a protective agent. A thin ferromagnetic I11 metal layer is formed to sufficiently suppress corrosion from the sides of the magnetic recording medium and provide durability even when running for long periods of time. Ai].

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 shows an example of a vacuum garnishing apparatus 0) used in the present invention, where l is a vacuum tank, and the inside of the vacuum tank 1 is maintained in a vacuum by an exhaust system 2. 3 is a cylindrical folding pin 4 disposed in the center of the vacuum chamber 1, and is made of a polyester fin having irregularities. The base film 4 is moved from the raw roll 5 along the 14 sides of the cylindrical key 4 and 3, and is wound onto the winding roller 5). During this time, the protective agent 8 is first heated and evaporated in the protective agent source 7 disposed at the bottom of the vacuum chamber 1, facing the base film 4 that moves along the circumferential side of the cylindrical cylinder 3. The steam streamer is directed at the base film 4 at a high angle and the protective agent 0)
Vapor deposition takes place. By oblique incidence deposition of this protective agent,
As shown in FIG. 2, a protective agent 9 is applied to a portion of the base film 4 having irregularities adjacent to the protrusions 41, and the voids formed adjacent to the protrusions 41 are filled with the protective agent 9.

Reference numerals 10 and 11 denote deposition prevention plates for adjusting the incident angle to the base film 4 that moves along the circumferential side of the cylindrical can 3 of the vapor stream obtained by heating and evaporating the protective agent, and this deposition prevention plate As shown in FIG. 2, the incident angle of the vapor flow A adjusted by 10 and 11 is caused by the shadow effect when ferromagnetic material is deposited at an oblique incidence.
It is preferable to set the angle of incidence to be high within the range of 70 to 90 degrees so that the protective agent can be deposited within the range that can fill the gap that occurs adjacent to 1. If this is done, the protective agent is deposited beyond the gap formed adjacent to the protrusion 41 of the base film 4 due to the shadow effect when the ferromagnetic material is deposited at an oblique incidence, which adversely affects the electromagnetic conversion characteristics.

The base film 4 has the protective agent 9 adhered to the portion adjacent to the protrusion 41 in this manner. After being once wound up on the take-up roll 6, it moves in the opposite direction from the take-up roll 6 along the circumferential side of the cylindrical can 3, and is wound up on the raw fabric 1 coil 5. During this time, the ferromagnetic material 13 is heated and evaporated by the ferromagnetic material evaporation source 12 disposed at the bottom of the vacuum chamber 1 by rotating the base film 4 moving along the circumferential side of the cylindrical can 3 once. Vapor flow B is directed onto the substrate film 4 for vapor deposition. At this time, the steam flow B is directed to the cylindrical can 3 at an angle within a predetermined range by anti-adhesion plates 14 and 15 provided at the bottom and sides of the cylindrical can 3.
Oblique incidence deposition is performed by directing the ferromagnetic metal thin film layer 16 onto the substrate film 4 moving along the circumferential side of the ferromagnetic metal thin film layer 16 on the portion adjacent to the projection 41, as shown in FIG. is formed on the base film 4 to which is attached.

The protrusions 41 of the base film 4 having irregularities in this way
A protective agent 9 is applied to the area adjacent to the
Second, when the ferromagnetic metal thin film layer 16 is formed, the ferromagnetic metal is deposited with the protective agent 9 filling the voids formed adjacent to the protrusions 41 due to the shadow effect peculiar to obliquely incident evaporation of the ferromagnetic material. Since the thin film layer 16 is formed, the ferromagnetic metal thin film layer is formed without creating voids due to the shadow effect peculiar to oblique incidence evaporation, and corrosion from the sides of the magnetic recording medium is sufficiently suppressed, and the ferromagnetic metal thin film is formed. The strength of the lower part of the layer is also strengthened, providing sufficient durability even when running for long periods of time.

The protective agent 9 to be applied by vacuum deposition or the like to the portion of the substrate film 4 having such unevenness adjacent to the protrusion 41 may be a polyethylene resin, a polyester resin, a cellulose resin, an epoxy resin, or a styrene resin. , phenoxy resin, acetate resin, acrylic resin, etc., as well as Ta
, Pt, O3, Rh, and other noble metals are preferably used, and specific examples include, for example, ester resin RV-1.
03 (polyester resin manufactured by Toyobo Co., Ltd.), ethyl cellulose, F, AI'3 (cellulose acetate manufactured by Dow Chemical Co., Ltd.), Epiclon (epoxy resin manufactured by Dainippon Ink & Chemicals Co., Ltd.), Styron (styrene resin manufactured by Asahi Dow Co., Ltd.),
Examples include PK HH (phenoxy resin manufactured by U, C, C).

The base film ζ is polyester, polyimide 1-
, plastic films made from commonly used polymer moldings such as polyamide 1', which have protrusions formed by processing them, or protrusions formed on these plastic films using organic substances, inorganic substances, etc. is used, and the ferromagnetic material forming the ferromagnetic metal thin film layer is Co, , Fe XN i-, Co
N' alloy, Co-Cr alloy, C0-P alloy, Co
A ferromagnetic material commonly used in vacuum deposition, such as a -Ni-P alloy, is used.

〔Example〕

Next, embodiments of the invention will be described.

Example 1 A polyester film 4 having a thickness of 12 μm and having protrusions 41 as high as 100 people on its surface was loaded into the vacuum deposition apparatus shown in FIG. It was moved and set to be wound onto the winding roll 6. Next, the inside of the vacuum chamber 1 is heated by the exhaust system 2 to lXl0')-
The polyethylene 8 set in the protective agent evaporation source 7 is heated and evaporated at a rate of 10 people/sec.
Vapor deposition was performed using the deposition prevention plates 10 and 11 at an incident angle of 80 degrees, and polyethylene was deposited on the portions of the polyester film 4 adjacent to the protrusions 41. Next, the inside of the vacuum chamber 1 is heated 5X.
The vacuum was evacuated to 10-5 torr, and the polyester film 4, which had been wound onto the take-up roll 6, was moved along the circumferential surface of the cylindrical can 3 in the opposite direction to the direction in which polyethylene was applied, and the ferromagnetic material was evaporated. Cobalt 13 placed in a source 12 is heated and evaporated at a rate of 30 people/sec, and is deposited on a polyester film 4 coated with polyethylene to a thickness of 10
A ferromagnetic metal thin film layer consisting of 0.000000000 cobalt was formed. Thereafter, the polyester film 4 is cut into a predetermined width, and as shown in FIG. 2, a protective agent 9 is applied to a portion of the polyester film 4 adjacent to the projections 41, and a ferromagnetic metal thin film layer 16 is further applied thereon. I made magnetic tape A.

Comparative Example 1 Example 1 odor °ζ, protrusion 4 of polyester film 4
A magnetic tape was produced in the same manner as in Example 1, except that the adhesion of polyethylene to the portion adjacent to Example 1 was omitted.

Comparative Example 2 Except for Comparative Example 1, in which a 0.1% by weight methyl isobutyl ketone solution of stearic acid was applied to the ferromagnetic metal thin film layer-L to form a hot water agent layer made of stearic acid with a dry thickness of 200 g. A magnetic tape was produced in the same manner as in Comparative Example 1.

Regarding the magnetic tape obtained in each example and comparative example,
Corrosion resistance and durability were tested, and the coefficient of dynamic friction was measured.

The corrosion resistance test was carried out by leaving the obtained magnetic tape in an atmosphere of 60°C and 190% RH for one week, measuring the saturation magnetization after standing, and calculating the rate of deterioration from the initial saturation magnetization. . The durability test was conducted by measuring the still life using a commercially available VTR deck.

The table below shows the results.

Table [Effects of the Invention] As is clear from the above table, the magnetic tape obtained in Example 1 had a lower
The deterioration rate is small and the durability is good, which shows that the magnetic recording medium obtained by the method of the present invention has excellent corrosion resistance and durability.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view of a vacuum binding device used in the manufacturing method of the present invention, and FIG. 2 is a partially enlarged sectional view of a magnetic recording medium obtained by the manufacturing method of the present invention.

Claims (1)

[Claims] 1. A protective agent is applied to a portion of a base film having projections adjacent to the projections, and a ferromagnetic metal thin film layer is provided by further applying a ferromagnetic material thereon. Characteristic magnetic recording medium 2: A base film having protrusions is moved along the circumferential side of a cylindrical can in a vacuum atmosphere, and a vapor flow obtained by heating and evaporating a protective agent onto this base film is applied at a high incidence angle. The protective agent is applied to the portion of the base film adjacent to the protrusion, and then the base film is moved along the circumferential side of the cylindrical can in the opposite direction to the direction in which the protective agent was deposited. , magnetic recording characterized in that a ferromagnetic metal thin film layer is provided on a base film coated with a protective agent adjacent to the projections by obliquely depositing a vapor flow obtained by heating and evaporating a ferromagnetic material. Media manufacturing method