JPS61177625A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain the titled magnetic recording medium wherein both traveling property and durability are especially improved by providing a layer contg. the phosphoric ester of a saturated or unsaturated alcohol or its metallic salt and a fatty acid or the metallic salt of the fatty acid on a ferromagnetic metallic thin film on a carrier. CONSTITUTION:A film contg. the mono-, di- and triester of phosphoric acid preferably having a 10-30C saturated or unsaturated hydrocarbon group or the phosphoric ester, which can be replaced by the salts of Ba, Ca, Na, K, NH4, etc. in case of a mono- or diester, and jointly contg. at least one among a >=10C fatty acid or its metallic salt or NH4 salt is formed in 50-500Angstrom thick ness on the ferromagnetic metallic thin film on a carrier of a polyester film, etc. An excellent lubricant layer is thus formed, and an excellent magnetic recording medium with reduced friction, improved traveling property and durabil ity, reduced spacing loss, a long stall file, and reduced distortions of the upper and the lower edge of the image or scews is obtained.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a magnetic recording medium, and particularly to a magnetic recording medium in which a ferromagnetic metal thin film is provided on a support, and more specifically to a magnetic recording medium in which a thin ferromagnetic metal film is provided on a support. The present invention relates to a magnetic recording medium with improved durability.

(Prior Art) Magnetic recording media such as magnetic tapes, magnetic sheets, and magnetic squares are widely used in the audio, video, and computer fields. For example, magnetic tapes of this kind are made by dispersing ferromagnetic powder in a binder and are of a nine-coat type. However, as the demand for high-density recording has recently increased, the recording density of this coated type has become smaller due to the amount of binder. Direct vapor deposition, sputtering,
Thin-film magnetic recording media in which a ferromagnetic metal thin film can be formed on a support by ion blating or the like have come into widespread use.

However, the ferromagnetic layer of such a thin film type recording medium has a large coefficient of friction, so when it is run on, for example, a video deck, it may be rubbed by a magnetic head, producing a frictional noise called tape squeal. If this friction is severe, the tape may come to a halt, causing not only poor running performance but also the possibility of scratches due to friction with magnetic heads, guide rollers, liners, etc.

For this reason, the so-called still durability when viewing still images when used as a videotape, and the so-called repeat durability when viewing a still image when the tape is played repeatedly, are significantly lower than those of the coated type. The current situation is that it is inferior and far from practical use. Furthermore, when a thin metal film is exposed to air, the metal is oxidized by the presence of oxygen and moisture, resulting in poor corrosion resistance. For example, iron oxide, which is produced when subjected to oxidative corrosion, exhibits no magnetism, which not only reduces the recording density as a recording medium, but also causes noise in the corroded areas and scratched areas. There is a book that could be the cause.

In order to solve these problems, a coating film is provided on the ferromagnetic metal thin film, but in this case, it is necessary to reduce the so-called spacing loss that accompanies the loss of output when scanning the magnetic layer with a magnetic head. Therefore, it is necessary to reduce the film thickness.

In order to solve these problems, various inorganic or organic compounds have been conventionally attached to or overcoated on the surface of the magnetic layer.
No. 540 discloses a magnetic recording medium in which a metal thin film layer is provided with a layer mainly composed of polyurethane resin. Furthermore, Japanese Patent Laid-Open No. 133631/1983 discloses a magnetic recording medium in which a sorbitan ester is deposited on a metal thin film layer. However, these durability is still insufficient for practical use, especially when rubbed by a magnetic head.
No. 8-146027 discloses a magnetic recording medium in which a surface treatment film made of phosphate ester or its metal salt is provided on a metal thin film. The invention also states that metal salts of phosphoric acid esters are preferred. However, even with this metal salt of phosphoric acid ester, durability such as the above-mentioned tape squeal and still durability is not sufficient.

In particular, recent trends in magnetic recording technology include, for example, the shift from the use of compact cassettes to microcassettes in audio tapes, and the shift from the current VH8 and β formats to 8mm video in the video field. With the shift to electronic cameras, the trend is toward further miniaturization and higher density. For example, when it comes to magnetic tape, its path has become complicated, causing contact with guide poles, guide rollers, etc. Since there are many opportunities to rub, there is a need for further improvement in mechanical properties such as runnability and durability, and the metal salts of phosphoric acid esters described above cannot satisfy the practicality.

In addition, Japanese Patent Application No. 191686/1986 describes a trialkyl phosphate ester in which a carbon fiber is ester-linked with 10 or more alkyl groups, which can be applied to the same purpose. Although the properties and durability have been improved, further improvement is desirable for practical use. For this reason, there is a desire to develop a magnetic recording medium that has runnability and durability that meets recent demands.

(Object of the Invention) An object of the present invention is to provide a magnetic recording medium having a ferromagnetic metal thin film layer that maintains runnability, has excellent durability, and satisfies the above-mentioned recent demands.

(Structure of the Invention) An object of the present invention is to provide a magnetic recording medium having a ferromagnetic metal thin film on a support, in which a saturated or unsaturated alkyl phosphate ester and/or a metal salt thereof and a metal salt thereof are provided on the ferromagnetic metal thin film. It is released by directly or indirectly depositing a layer containing fatty acids and/or their metal salts. In the present invention, "directly attached" means to be present on the ferromagnetic metal thin film by coating, etc., and "indirectly" means to be included in a layer provided as an upper layer of the film, or It is to be present and caused to exist on the upper layer by coating.

Next, the present invention will be explained in detail.

The stone alkyl phosphates used in the present invention include triplekyl phosphates, dialkyl phosphates and monoalkyl phosphates, where alkyl can be saturated or contain an unsaturated moiety; It may have various branches.

In addition, in the case of dialkyl phosphate esters and monoalkyl phosphate esters, metal salts and ammonium salts are suitable.As metal salts, palicum salts, magnesium salts, calcium salts, natrium salts, potassium salts, lithium salts, etc. included. That is, expressed as a general formula, it is as follows.

Trialkyl phosphate ester Dialkyl phosphate ester Monoalkyl phosphate ester Here, Ht, Ht, and Hm each represent a saturated or unsaturated alkyl group, and each preferably has at least 10 carbon atoms and no more than 10 carbon atoms. .

M includes hydrogen, palicum, magnesium, calcium, sodium, potassium, lithium, ammonium, and the like.

Furthermore, among these, trialkyl phosphate esters are most preferred.

Specific examples thereof include, but are not limited to, compounds of the same name.

(i) (C+.H□0\p=Q Cυ (Cl4H1・0) island p=Q(3)
(C1·H□O), P-0 (4) (C,, H□o), p=.

(5) (C,,H,,O)(C,2 1(,,
O), P = = 0 (6) (C * a Hag O) 1 P wealth 0 (7) (CI6H□o), p =.

Sodium Na Nm The fatty acid or the metal salt thereof used in the present invention is specifically exemplified by a compound of amberjack, but is not limited to these.

(1) C, IH,, C00H (2) C□H,, C00H (3) CnH□C00H (4) C1q Has C00H (5)
C, Te Ham C00H(6) C,. H,
, C00H (71C,H□C0OH) and their metal salts (for example, sodium, potassium, ammonium, lithium, calcium, etc.).A layer containing these two types of compounds is added to the ferromagnetic metal thin film described later. When deposited, the ferromagnetic metal thin film provides lubricity when it is rubbed against a magnetic head, for example.

In addition, running performance and durability are significantly improved.

In addition, the layer containing these two types of compounds may be applied directly onto the ferromagnetic metal thin film by coating or the like, or may be applied to a lubricant layer, a rust preventive layer, or an intermediate layer laminated on the thin film. It can be indirectly attached to the thin film by containing it or making it exist thereon by coating or the like.

The combined ratio of the phosphoric acid ester and/or its metal salt and the fatty acid and/or its metal salt is preferably 10 to 1000 parts by weight of the latter to 100 parts by weight of the former.

These compounds form an elbow pad on a thin ferromagnetic metal film. If the film is thicker than this, the spacing loss will increase,
If it is thinner than this, the lubricity effect will be reduced.

A film containing a mixture of these compounds is formed by application of a paint, which paint contains a mixture of said compounds at 0.5%.
It consists of an organic solvent solution containing from 1% by weight of 005 to 1% by weight.

Organic solvents for this purpose include toluene, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, xylene, benzene, cyclohexanone, methanol, ethanol, propatool, ingropanol, butanol, ethyl cellosolve, methyl cellosolve, etc. alone or in combination. used.

Note that commonly used additives such as lubricants can also be used together with the above two types of compounds.

To apply this paint, the dipping method involves dipping the paint in the above paint, the hearth roll method, the extrusion method, the doctor blade method, and the method of applying this paint.
A gravure printing method, a spray method, etc. are used, and the coating film applied by these methods is dried by a conventional method.

The ferromagnetic metal thin film in the present invention is Fe.

Metal such as C01Ni or Fe-Co, Fe-N
i, Co-Ni, Fe-Co-N1, Fe
-Rh%Fe-Cu, Co-Cu%Co-Au
.

Co-Y%Co-La, Co-Pr, Co-
Gd, Co-8m, Co-Pt.

Ni-Cu, Mn-pu, Mn-8b%Mn-Al,
Fe-Cr, Co-Cr%N1-Cr, r
A ferromagnetic alloy such as e-Co-Or or re-Co-Nl-Cr formed into a thin film by vacuum deposition is used. The thickness of this metal thin film is 500A' to 5
00OA' position is preferable.

Furthermore, those deposited in an oxygen atmosphere exhibit better durability.

The support on which the metal thin film is formed is a plastic base such as polyester, polyethylene terephthalate, polyimide, polyamide, polyamideimide, polyvinyl chloride, cellulose triacetate, polycarbonate, polyethylene naphthalate, or AI, A1 alloy,
Metal plates such as TI, T1 alloy, stainless steel, etc. are used.

(Effects of the Invention) As explained above, the present invention provides a method in which a layer containing a phosphoric acid ester and/or a metal salt thereof and a fatty acid and/or a metal salt thereof is deposited directly or indirectly on a ferromagnetic metal thin film. Therefore, due to its excellent lubricity, the coefficient of friction of the thin metal film is reduced even with a relatively thin film, which reduces the friction against the magnetic head and guide roll, improving its running performance and increasing its durability. can. Thereby, so-called tape squeal can be prevented and methyl durability and repetition durability can be increased.

In addition, it does not impair contact resistance and reduces spacing loss.

(Implementation sequence) Next, the present invention will be described in detail, but the present invention is not limited thereto.

Implementation 9) Ill C on 12μ thick polyethylene terephthalate.

-Nl (Ni 20% by weight) was deposited to a thickness of 1000 nm to form a metal thin film layer. The film thickness after drying the 15 types of lubricant solutions shown in Table 1 below on this metal thin film is ts.
Samples 1 to 15 were obtained by coating, drying, slitting, and packing in cassettes to obtain samples 1 to 15. In all cases, a mixed solvent of badruene and ethyl cellosolve at a ratio of 9:1 (weight ratio) was used as the solvent.

Procedural amendment April 19, 1986

Claims (1)

[Claims] In a magnetic recording medium having a ferromagnetic metal thin film on a support, a layer containing a saturated or unsaturated alkyl phosphate ester and/or its metal salt, and a fatty acid and/or its metal salt on the ferromagnetic metal thin film. A magnetic recording medium characterized by having: