JPH04106717A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve both of electromagnetic conversion characteristics and durability of a magnetic recording medium having a magnetic layer on a nonmagnetic supporting body and having a back coating layer on the other side of the supporting body, by forming a stainless steel thin film on one side of the nonmagnetic supporting body. CONSTITUTION:A magnetic layer is provided on one side of a nonmagnetic supporting body, while a back coating layer is provided on the other side of the supporting body. A stainless steel thin film is formed on at least either side of the nonmagnetic supproting body. The stainless steel thin film is preferably 0.1-1.2mum thick, and more preferably 0.1-0.8mum thick. Any conventional, well-known materials may be used as a binder, crossliking agent, abrasive, dispersant added as required, plasticizer, antistatic agent, and for the nonmagnetic supporting body, back coating layer, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording medium used in video, audio equipment, computers, etc., and more particularly relates to a thin magnetic recording medium suitable for long-term use. The present invention relates to tapes and their supports.

BACKGROUND OF THE INVENTION In recent years, each of these magnetic recording media has become suitable for high-density recording, and for this purpose, the trend has been to shorten the recording wavelength, narrow the recording track width, and reduce the thickness of the recording medium.

As a result, the S/N ratio, anger level, and frequency characteristics are generally inconsistent.
However, as a countermeasure to this problem, methods have been adopted such as pulverizing the magnetic powder and making the magnetic layer highly smooth. However, if the above measures are taken alone, the surface smoothness of the magnetic layer increases, which increases the coefficient of friction, resulting in disadvantages in terms of runnability and durability. A method is known in which a back coat layer is provided on the surface of the support opposite to the magnetic layer surface.

Problems to be solved by the inventionHowever, the conventional methods as mentioned above, durability,
In particular, there were problems such as deformation of the magnetic tape and deterioration of electromagnetic conversion characteristics.

The present invention solves the above problems and aims to provide a highly durable magnetic tape that has excellent electromagnetic conversion characteristics and is also resistant to deformation of the magnetic tape and deterioration of magnetic conversion characteristics.

Means for Solving the Problems In order to solve the above problems, the present invention provides a magnetic recording medium in which a magnetic layer is provided on a non-magnetic support and a coat layer is provided on the opposite surface. The present invention is characterized in that a stainless steel thin film is formed on at least one surface of the support, thereby obtaining a magnetic recording medium with excellent durability and electromagnetic conversion characteristics.

The film thickness of the stainless steel FR film in the present invention is 0.1 μm
It is preferably 12 μm, more preferably 0
．． It is 1 μm to 0.8 μm.

Operation The present invention improves the mechanical strength of the magnetic tape and eliminates the adverse effects caused by deformation of the magnetic tape, especially the durability. In other words, magnetic recording media, such as magnetic tape for video recorders, are wound around various posts at a fixed angle and run, but in order to regulate the position of the various posts in the height direction, there is a A regulation post is provided on the upper side of the tape.If the tape attempts to detach from the regulation post and run, the tape will basically prevent the tape from detaching due to the undulation of the tape itself. There must be.

However, as the overall thickness of the tape decreases, the rigidity of the tape decreases, resulting in the tape bending, the edges of the tape becoming seaweed-like, or in the worst case, the tape breaking and causing serious damage. By forming a stainless steel IF film on at least one side of the non-magnetic support as in the present invention, when the tape is locally bent, the elastic modulus, Because the tape is made of a thin metal film with high tenacity, a reaction force acts on the tape, increasing the bending and torsional rigidity of the tape, greatly improving its durability, especially its deformation. Furthermore, with the above configuration, by improving the mechanical strength in the longitudinal and width directions of the magnetic tape and maintaining a balance between them, it is possible to obtain magnetic keep with high F-helobe output flatness and excellent electromagnetic conversion characteristics. .

Examples The present invention will be explained below. Here, the present invention - binder in two layers, crosslinking agent, abrasive, 4. Dispersion f added as required
11. As the desensitizing agent, antistatic agent, nonmagnetic support, back coat layer, etc., conventionally known ones can be used.

Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited thereto.

EXAMPLES; All component ratios shown here (1 part) are parts by weight.

Tenshu example 1 The magnetic paint was adjusted as follows.

F-based alloy magnetic powder coercive force Hc = 15500e, BET specific surface area = 56
T1(,/g, saturation magnetization δs=127emu7・
g, acicular ratio -8/1: Vinyl chloride vinyl acetate copolymer resin, 0 parts PO □ 1 Ure Tanoki l effect - 0 parts 5 [IP
l (AI: 203): Average particle size - 0.2 μm) 6 parts car t7・Fu-7・ri 1 part Average particle size -20 μm:・2
Part mini 1st/acid 1 part Phthyl scearate 1 part Methyl ethyl ketone 100 parts Toluene L-100
60 parts of chlorhexanone The above composition was cross-mixed using a pressure kneader and a sand mill to prepare a magnetic coating material. The resulting magnetic paint
Add 1514 parts of Desmodor (manufactured by Bayer Co., Ltd.) to J Inno Noor 1st Compound 'l1y11, mix well with a surface speed) jI genitalia, filter with an average filter of 1 μm in diameter, and remove the magnetic paint m (ii was carried out.

Next: 7.5. ! With a thickness of 7 m, the tensile Young's modulus in the longitudinal direction is 680 kR/mm2, and the tensile Young's modulus in the width direction is 620 kg, /+nm. The polyester formed from this:] Process 4-L7/Terephthalate film was coated on two coats, magnetic field was distributed, and after the drying process, a mirror finish treatment using Super Cale/Darroll Ni was applied to the original film having a 26 μm thick magnetic layer. I got Uru.

The second raw fabric roll was subjected to hardening treatment T3, and then a back coat layer with a thickness of 05 μm was applied to the stainless steel thin film roll.
A 5-inch diameter sample (250 m long) was made by cutting a 2-inch diameter.

Example 2 A videotape sample was prepared in the same manner as in Example 1, except that the polyethylene terephthalate film in Example 1 was replaced with a polyethylene terephthalate film on which a 1.1 μm thick stainless steel thin film was formed on the bank coat layer side. was created.

Comparative Example 1 A videotape sample was produced in the same manner as in Example 1, except that the polyethylene terephthalate film of Example 1 was replaced with an ordinary polyethylene terephthalate film without stainless steel.

Comparative Example 2 A videotape sample was prepared in the same manner as in Example 1, except that the polyethylene terephthalate film in Example 1 was replaced with a polyethylene terephthalate film on which a 1.6 μm thick stainless steel thin film was formed on the surface on the hack coat layer side. was created.

Example 3 A videotape sample was prepared in the same manner as in Example 1, except that the polyethylene terephthalate film in Example 1 was replaced with a polyethylene terephthalate film on which a 2 μm thick stainless steel thin film was formed on the surface on the magnetic layer side.

Example 4 The polyethylene terephthalate film of Example 1 was coated on both sides of the magnetic layer side and the back coat layer side, each with 0.2
A videotape sample was prepared in the same manner as in Example 1 except that a polyethylene terephthalate film having a μm-thick stainless steel thin film was used.

The following evaluation tests were conducted on the videotape samples G obtained in each of the above Examples and Comparative Examples.

(1) Stiffness The stiffness of the magnetic tape was measured using a commercially available Lube Stiff 7 tester when it was twisted into a linog shape with a circumference of 100 m.

(2) Enherobe output flatness rate Using a VH3 system VTR (\V = FS900 manufactured by Matsu T Denki Co., Ltd.) which uses an amorphous alloy for recording and reproduction, the enherobe at a recording frequency of 5 MHz was measured for each videotape sample. The output flatness rate was measured.

(3) Deformation of tape Using the VTR described in (2), each videotape sample was
After running 200 times in an environment of °C and 80% RH, the deformation of the tape sample was visually observed and evaluated on a five-point scale. Evaluation (Practical) 2: 5 for no problems at all, 1 for practical problems.

(4) Audio level fluctuation The output of the audio head was rectified, and the level fluctuation of the output was measured after the test according to (3) above.

(5) Dropout Momentary drops in the video signal were measured before and after the test according to (3) above using a dropout counter.The dropout counter shows the change rate after the test compared to before the test as a magnification.Obtained results Table 1 shows this.

(Margins below) 壬〒; / ふ 0 0 こ ~ OOt knee t ~ − = き W ; :l 2j −−
〒 S ≧ Leap S ko 〒
[寥茶 −−− daura; Kurekō; ; f ＆′g −♂ f beaji−ni (− As is clear from Table 1, a magnetic layer is placed on a nonmagnetic support and a back coat is applied to the opposite side. By forming a stainless steel 1III thin film on at least one surface of a non-magnetic support in a magnetic recording medium having layers, it is possible to improve electromagnetic conversion characteristics, especially enherobe output flatness, durability, especially tape deformation, audio A magnetic tape with excellent resistance to level fluctuations and dropouts can be obtained.

In the above examples, the stainless steel thin film was formed on the nonmagnetic support by a vacuum spreading method, but the same effect can be obtained by using a sputtering method.

Effect of the invention

Claims (1)

[Claims] A magnetic recording medium in which a magnetic layer is provided on one surface of a non-magnetic support and a back coat layer is provided on the other surface, wherein a stainless steel thin film is formed on at least one surface of the non-magnetic support. A magnetic recording medium characterized by: