JPS6222173B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a magnetic recording medium, and by providing a resin layer containing titanium monoxide and a lubricant on the base surface opposite to the magnetic layer, electromagnetic conversion characteristics such as video S/N and video sensitivity can be improved. The object of the present invention is to provide a magnetic recording medium that has excellent characteristics such as abrasion resistance and runnability. In recent years, as magnetic tapes for high-density recording, for example, for video tape recorders, have become widespread, such magnetic tapes have problems such as video S/N, video sensitivity, abrasion of guide poles and guide posts of video tape recorders, scinning phenomenon, etc. Improving the balance between noise during tape running and overall characteristics has become an issue. However, in the past, even though the video S/N and video sensitivity characteristics were excellent to a certain extent, tape winding became loose, the tape was damaged, and the guide post on the recording/playback device side was often worn out. Even if a product is excellent in some characteristics, it has disadvantages in that it is not a comprehensively balanced characteristic, just as it is said to be inferior in other characteristics. The present invention eliminates the above-mentioned drawbacks, that is, the back surface of the magnetic recording medium has an average particle size of 0.01 to
By coating titanium monoxide with a thickness of 5 μm, preferably 0.015 to 0.2 μm, and a lubricant using a binder resin, the above-mentioned overall characteristics are improved, resulting in an excellent and well-balanced magnetic recording medium. He discovered that Furthermore, the amount of titanium monoxide added to the binder resin layer provided on the back surface of the magnetic recording medium is approximately 100% relative to the binder resin content in the binder resin layer.
50 to 200% by weight, the amount of lubricant added is approximately 5 to 30% by weight based on the binder resin content in the binder resin layer.
It has also been found that it is preferable that the Some embodiments of the magnetic recording medium according to the present invention will be described below. Examples 1 to 4 A magnetic paint made of a magnetic powder such as Co-containing γ-Fe ₂ O ₃ , a binder such as vinyl chloride-vinyl acetate copolymer, a solvent such as methyl ethyl ketone, etc. is applied to one side of a base such as a polyester film. The magnetic layer is formed by applying a predetermined thickness, and on the other side of the base, 100 parts of titanium monoxide with an average particle size of 0.05 to 0.2 μm and a hydrocarbon lubricant (liquid paraffin,
Natural paraffin, micro wax, polyethylene wax) 20 parts, polyurethane elastomer 80 parts
A mixed and dispersed solution of 30 parts of vinyl chloride-vinyl acetate-vinyl alcohol copolymer and 600 parts of methyl ethyl ketone is coated to a thickness of 0.2 to 2 μm, for example, about 1 μm, to form a back coat layer and obtain a magnetic tape for a video tape recorder. . Examples 5 to 8 Magnetic tapes are obtained in the same manner as in Example 1 except that the liquid paraffin in the back coat layer of Example 1 is replaced with a fatty acid lubricant (stearic acid, lauric acid, palmitic acid, oleic acid). Examples 9 to 12 The liquid paraffin of the back coat layer of Example 1 was mixed with a fatty acid amide lubricant (stearic acid amide, palmitic acid amide, methylene bisstearamide,
A magnetic tape is obtained in the same manner as in Example 1 except that ethylene bisstearamide) is used. Examples 13-17 The same procedure as in Example 1 was carried out except that the liquid paraffin in the back coat layer of Example 1 was replaced with an ester lubricant (isopropyl myristate, isoamyl stearate, butyl stearate, hexyl laurate, oleyl oleate). Get magnetic tape. Examples 18 to 24 The liquid paraffin of the back coat layer of Example 1 was mixed with a silicone lubricant (the following general formulas () to ()).
A magnetic tape is obtained in the same manner as in Example 1, except that (However, R ₁ and R ₂ are hydrogen atoms or carbon atoms 1 to 18
The monovalent hydrocarbon group, R ₃ and R ₄ have 2 to 2 carbon atoms.
17 divalent hydrocarbon groups) (However, R and R' are hydrocarbon groups having 7 to 26 carbon atoms,
n is an integer from 1 to 20) (However, R and R' are hydrocarbon groups having 8 to 18 carbon atoms,
R'' is a hydrogen atom or a methyl group, n, m and l are
A natural number that satisfies the conditions of 1≦m<15, 2≦n+l≦16) (However, n is a natural number from 1 to 50) (However, R ₁ is a monovalent hydrocarbon group having 1 to 6 carbon atoms, R ₂
is a monovalent hydrocarbon group having 7 to 21 carbon atoms, X is hydrogen or a fluorine atom, n is an integer of 1 to 4, m is an integer of 1 to 3) (However, R ₁ is a saturated or unsaturated 1 having 7 to 21 carbon atoms.
valence hydrocarbon group, R ₂ is a methyl group or phenyl group,
R ₃ is a group represented by -OCOR ₁ , Y is -[CF ₂ ] _-k W
(However, k is an integer from 1 to 8, W is hydrogen or fluorine atom), l, m and n are 0≦l≦200, 1≦m<
100, an integer that satisfies the conditions of 1≦n<100, l+m+n≦300) (However, R is a saturated or unsaturated 1 having 7 to 21 carbon atoms.
R ₁ , R ₂ and R ₃ are RCOO groups, R ₄ is a monovalent saturated hydrocarbon group having 6 to 20 carbon atoms, k, l,
m and n are 1≦k, 1≦l<200, 1≦m<
Comparative Example 1 A magnetic tape was obtained in the same manner as in Example 1, except that liquid paraffin was not added to the back coat layer of Example 1. Comparative Examples 2 to 5 Magnetic tapes were obtained in the same manner as in Example 1, except that CaCO ₃ was used in place of the titanium monoxide in the back coat layer of Examples 1 to 4. Comparative Example 6 A magnetic tape was obtained in the same manner as in Example 18 except that CaCO ₃ was used in place of the titanium monoxide in the back coat layer. Regarding the magnetic tape obtained as described above, the video S/N, video sensitivity, noise during running, tape winding slack occurrence rate, degree of abrasion, and degree of wear of the guide post of the recording/reproducing machine were measured as shown in the table. It is.

【table】

[Table] As can be seen from the above results, the magnetic tape in which a binder resin layer containing TiO and a lubricant is provided on the opposite side of the support from the magnetic layer has high video S/N and video sensitivity. Low noise while driving
The electromagnetic conversion characteristics are good, and the magnetic tape is less prone to scratches and loosening of the tape.Furthermore, the coefficient of friction does not increase significantly even after repeated running, resulting in good running performance. It turns out that it is something. Furthermore, since the magnetic tape is less likely to be damaged, output fluctuations and dropouts are less likely to occur. In addition, the tape winding end surfaces are well aligned when the tape is fed at high speed, and there is little variation in signal output due to tape deformation or the like. Further, the magnetic tape of this embodiment has extremely good tape running properties and tape winding appearance, such as leaving the end of the tape in a free state and causing no slack in the winding even when the tape is rapidly stopped. Furthermore, when measuring the surface electrical resistance of the back surface of the magnetic tapes for the above magnetic tapes, the resistance of the magnetic tapes of this example was as low as 10 ⁸ Ω or less, whereas that of Comparative Examples 2 to 6 was 10 ⁸ to 10 ^{9 Ω} . Ω, and as a result, the antistatic effect was not sufficient, and dirt and dust were likely to adhere to it. Although no direct comparative examples are shown for Examples 5 and below, the comparison examples for Examples 5 and below, which do not contain both TiO and a lubricant in the back coat layer, are similar to Comparative Examples 2 to 5. and
Magnetic recording media containing both TiO and a lubricant in the back coat layer have good and well-balanced overall properties in many properties such as electromagnetic conversion characteristics, runnability, and winding shape due to the synergistic effect of TiO and the lubricant. It is something that As described above, the magnetic recording medium according to the present invention has a magnetic layer on one side of the support and a resin layer containing titanium monoxide and a lubricant on the other side, so that it can be used for video S/S.
N. The video sensitivity is high, the noise while driving is low, and the electromagnetic conversion characteristics are improved.
It is less likely to be scratched, less likely to drop out, has excellent durability and runnability, and the tape has a good winding appearance. Furthermore, it is effectively anti-static and does not attract dirt or dust. It has the advantage that it is difficult to use, and the overall characteristics of the magnetic recording medium are improved.

Claims (1)

[Claims] 1. A magnetic recording medium characterized in that a magnetic layer is provided on one side of a support and a resin layer containing titanium monoxide and a lubricant is provided on the other side.