JPH04362511A - Magnetic recording tape - Google Patents

Abstract

PURPOSE:To obtain the thin magnetic recording tape which has excellent durability and electromagnetic conversion characteristics and is used for video and audio equipment, computers, etc. CONSTITUTION:The tensile Young's modulus of a magnetic layer is in a 1500 to 1800kg/mm<2> range at -10 deg.C and 1100 to 1800kg/mm<2> at 40 deg.C and 80% RH; further, the tensile Young's modulus in the longitudinal direction and transverse direction of a nonmagnetic base is >=600kg/mm<2>. Further, the rout means square surface roughness on at least either surface of the nonmagnetic base is in a 0.01 to 0.025mum range.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a magnetic recording tape used for video, audio equipment, computers, etc., and more particularly to a thin magnetic recording tape suitable for long-term use and its support. It is.

0002

2. Description of the Related Art In recent years, these various magnetic recording media are suitable for high-density recording, and for this purpose, the recording wavelength is becoming shorter, the recording track width is narrower, and the recording medium thickness is becoming thinner. As a result, the S/N ratio, sensitivity, and frequency characteristics are generally disadvantageous, but as a countermeasure to this problem, methods have been adopted such as making the magnetic powder finer and making the magnetic layer highly smooth. However, if the above-mentioned measures alone are used, the surface properties of the magnetic layer will increase, resulting in an increase in the coefficient of friction, which will be disadvantageous in terms of runnability and durability. It is known to provide a back coat layer on the opposite side of the magnetic layer.

0003

[Problems to be Solved by the Invention] However, with the above-mentioned conventional methods, there are problems with durability, especially the occurrence of powder falling off from the magnetic layer, scratches on the magnetic surface, deformation of the magnetic recording tape, and deterioration of electromagnetic conversion characteristics. There was a problem.

In view of the above problems, the present invention provides a highly durable magnetic recording tape that has excellent electromagnetic conversion characteristics and is also resistant to deformation of the magnetic recording tape, generation of falling powder, and deterioration of electromagnetic conversion characteristics. be.

[0005]

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a magnetic recording tape having a magnetic layer provided on a non-magnetic support, the tensile Young's modulus of the magnetic layer being -
1500-1800Kg/mm2 at 10℃, 40℃8
The tensile Young's modulus of the non-magnetic support in the length direction and the width direction is in the range of 1100 to 1800 Kg/mm2 at 0% RH, and the tensile Young's modulus of the non-magnetic support is 600 Kg/mm2 or more, and the surface root mean square of the non-magnetic support is The present invention is characterized in that the roughness of at least one surface is in the range of 0.01 to 0.025 μm, and the magnetic recording tape has excellent durability and electromagnetic conversion characteristics.

[0006]

[Function] With the above-described structure, the present invention provides a magnetic recording tape with improved electromagnetic conversion characteristics and excellent durability.

[0007] The durability of a magnetic recording tape is required to be minimal, such as a decrease in output and an increase in dropouts, in a wide range of environments from low temperatures to high temperatures and high humidity. Depending on the strength and hardenability of the binder used for the magnetic layer, the magnetic layer is greatly affected by temperature and moisture in a high temperature and high humidity atmosphere, resulting in deterioration of these properties, as well as the occurrence of powder falling off from the magnetic layer and damage to the magnetic surface. Significant deterioration of characteristics occurs due to scratches on the magnetic recording tape, deformation of the magnetic recording tape, etc. Furthermore, in a low-temperature environment, scratches on the magnetic surface are likely to occur, leading to a decline in still characteristics. These problems reduce the tensile Young's modulus of the magnetic layer to 1500 to 1800 Kg/mm at -10°C.
2. 1100-1800Kg/m at 40℃80%RH
If it is limited to the range of m2, sufficient improvement can be achieved.

Furthermore, especially in the case of a thin magnetic recording tape using a non-magnetic support with a thickness of 10 μm or less, in order to provide a certain level of mechanical strength in a well-balanced manner in the longitudinal and width directions, the thickness of the non-magnetic support must be By limiting the tensile Young's modulus in the longitudinal and width directions to 600 Kg/mm2 or more, a magnetic recording tape can be obtained that is excellent in durability, particularly in terms of deformation of the magnetic tape, envelope flatness, audio level fluctuation, etc.

In addition, the surface properties of the non-magnetic support on the side opposite to the magnetic layer side of the magnetic recording tape are transferred to the surface of the magnetic layer, and by preventing the negative effects caused by the decrease in surface properties, the electromagnetic conversion characteristics, especially C A magnetic recording tape with an excellent /N ratio can be obtained.

To explain in more detail, magnetic recording tapes, for example magnetic recording tapes for video tape recorders, are wound around various posts at a fixed angle and run, and the positions of the various posts in the height direction are regulated. For this purpose, lower regulation posts and upper regulation posts are provided. When the tape attempts to run away from the regulation post, it must basically run in such a way that it does not come off due to the rigidity of the tape itself. 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 scenario, the tape breaking and causing damage to important parts. You end up in a situation where you lose information.

[0011] In the magnetic recording tape in which a magnetic layer is provided on a non-magnetic support as in the present invention, the tensile Young's modulus of the magnetic layer is 1500 to 1800 Kg/mm2 at -10°C;
It is in the range of 1100 to 1800 Kg/mm2 at 40°C and 80% RH, and the tensile Young's modulus of the non-magnetic support in the longitudinal and width directions is 600 Kg/mm2 or more, so that the tape is not locally bent. Because the elastic modulus is well-balanced and high, a reaction force acts when the tape tries to bend, increasing the bending and torsional rigidity of the tape, increasing its durability and
In particular, the deformation of the tape is greatly improved.

0012

[Example] The present invention will be explained below. Here, conventionally known binders, crosslinking agents, abrasives, dispersants, plasticizers, antistatic agents, and back coat layers used in the present invention can be used.

[0013] The present invention will be specifically explained below with reference to Examples, but the present invention is not limited thereto. All "parts" in the component ratios shown in the examples are "parts by weight."
It shows.

(Example 1) The magnetic paint was prepared as follows.

[0015] Fe-based alloy magnetic powder

100 parts [Holding force HC = 1550
Oe, BET specific surface area = 56 m2 /g,
Saturation magnetization amount σS = 127 emu/g, acicular ratio = 9/
1] Vinyl chloride vinyl acetate copolymer resin

10 parts polyurethane resin

10 parts Abrasive (Al
2O3) [Average particle size = 0.2 μm]
6 parts carbon black [average particle size = 20mμ]
Part 2 myristic acid

1 part Butyl stearate

1 part methyl ethyl ketone
10
0 parts toluene

100 parts cyclohexanone
6
0 parts The above composition was kneaded and dispersed using a pressure kneader and a sand mill to prepare a magnetic paint. Three parts of a polyisocyanate compound [Desmodur L, manufactured by Bayer AG] was added to the obtained magnetic paint, and the mixture was thoroughly mixed and stirred using a high-speed stirrer, and then filtered through a filter with an average pore size of 1 μm to prepare a magnetic paint. Ta.

Next, the magnetic paint was made of polyethylene terephthalate having a thickness of 10.3 μm, a tensile Young's modulus in the length direction of 820 Kg/mm2, a tensile Young's modulus in the width direction of 470 Kg/mm2, and a surface root mean square roughness of 0.023 μm. After coating on a film support, magnetic field orientation, and drying treatment, mirror finishing treatment was performed using a super calendar roll to obtain a raw roll having a 2.6 μm thick magnetic layer. This raw roll was cured at 50°C for 24 hours.
Next, a 0.5 μm thick back coat layer was provided on the opposite side of the magnetic layer, and the videotape sample (
A length of 250 m) was produced.

(Example 2) A videotape sample was prepared in the same manner as in (Example 1) except that the amount of the polyisocyanate compound added to the magnetic paint in (Example 1) was increased from 3 parts to 6 parts.

(Example 3) A magnetic paint was prepared by adding 0.5 part of triazinedithiol, a curing accelerator for vinyl chloride resin, to the magnetic paint containing the polyisocyanate compound of (Example 1). ) A videotape sample was prepared in the same manner.

Comparative Example 1 A videotape sample was prepared in the same manner as in Example 1, except that the amount of the polyisocyanate compound added to the magnetic paint in Example 1 was reduced to 1 part.

(Example 4) The 24-hour curing treatment at 50°C in (Example 1) was performed at 60°C at 48°C.
A videotape sample was prepared in the same manner as in Example 1 except that the time curing treatment was changed.

(Comparative Example 2) A magnetic paint was prepared in which the amount of the polyisocyanate compound added to the magnetic paint of Example 1 was increased from 3 parts to 6 parts, and 1 part of triazinedithiol, a curing accelerator for vinyl chloride resin, was added. A videotape sample was prepared in the same manner as in Example 1, except that the 24-hour curing treatment at 50°C was changed to a 72-hour curing treatment at 60°C.

(Comparative Example 3) A videotape sample was prepared in the same manner as in (Example 1) except that the 24-hour curing treatment at 50° C. in (Example 1) was changed to no curing treatment.

(Example 5) The polyethylene terephthalate film support of (Example 1) was prepared with a thickness of 7.3 μm and a tensile Young's modulus of 8 in the longitudinal direction.
00Kg/mm2, tensile Young's modulus in the width direction is 750K
g/mm2, surface root mean square roughness 0.018μ
A videotape sample was prepared in the same manner as in Example 1 except that the support was changed to a polyethylene naphthalate film support.

(Comparative Example 4) The polyethylene terephthalate film support of (Example 1) was prepared with a thickness of 7.3 μm and a tensile Young's modulus of 1 in the longitudinal direction.
040Kg/mm2, tensile Young's modulus in the width direction is 550
Kg/mm2, surface root mean square roughness is 0.018
A videotape sample was prepared in the same manner as in Example 1 except that the support was changed to a .mu.m polyethylene naphthalate film support.

(Example 6) The polyethylene terephthalate film support of (Example 1) was prepared with a thickness of 7.3 μm and a tensile Young's modulus in the longitudinal direction of 6.
40Kg/mm2, tensile Young's modulus in the width direction is 660K
g/mm2, surface root mean square roughness 0.018μ
A videotape sample was prepared in the same manner as in Example 1 except that the support was changed to a polyethylene naphthalate film support.

(Comparative Example 5) The polyethylene terephthalate film support of (Example 1) was prepared with a thickness of 7.3 μm and a tensile Young's modulus of 5 in the longitudinal direction.
40Kg/mm2, tensile Young's modulus in the width direction is 560K
g/mm2, surface root mean square roughness 0.018μ
A videotape sample was prepared in the same manner as in Example 1, except that the sample was changed to one of m.

(Example 7) A videotape sample was prepared in the same manner as in (Example 1) except that the polyethylene terephthalate film support in (Example 1) was changed to one with a surface root mean square roughness of 0.013 μm. was created.

(Comparative Example 6) A videotape sample was prepared in the same manner as in (Example 1) except that the polyethylene terephthalate film support in (Example 1) was changed to one with a surface root mean square roughness of 0.028 μm. was created.

(Comparative Example 7) A videotape sample was prepared in the same manner as in (Example 1) except that the polyethylene terephthalate film support in (Example 1) was changed to one with a surface root mean square roughness of 0.008 μm. was created.

The following evaluation tests were conducted on the videotape samples obtained in each of the above Examples and Comparative Examples. (1) Tensile Young's modulus Using Tensilon universal tensile tester (UCT-100: manufactured by Orientec Co., Ltd.), 1/2 inch width, 100 m
The Young's modulus at 0.5% elongation was calculated by pulling a m-long sample at a speed of 1 mm/min. (2) Surface roughness It was determined by calculating the root mean square roughness of the height on a roughness chart using a Talystep stylus type surface roughness meter manufactured by Taylor Hobson. (3) VHS system VTR using an amorphous alloy head for the C/N ratio recording/playback head (NV-FS900, Matsushita Electric Co., Ltd.)
The recording frequency of each videotape sample was 7 MHz.
The C/N ratio was measured. As a standard tape,
M Zaformat VTR cassette tape (Matsushita Electric (
Co., Ltd., AU-M90L), and the C/N ratio was 0d.
It was set as B. (4) Envelope output flatness rate VHS system VTR using an amorphous alloy head for the recording/playback head (NV-FS900, Matsushita Electric Co., Ltd.)
The recording frequency was 7 MH before and after running each videotape sample for 200 passes in an environment of 40°C and 80% RH.
The envelope output flatness rate at z was measured. (5) Audio level fluctuation The audio head output was rectified, and the level fluctuation of the output was measured after the test according to (4) above. (6) Dropout Before and after the test according to (4) above, a dropout counter (manufactured by Shibasoku Co., Ltd., VH01)
BZ). Dropout was expressed as the rate of change after the test compared to before the test. (7) Deformation and scratches on the tape After the test in (4) above, the deformation and scratches on each tape sample were visually observed and evaluated on a five-point scale. The evaluation was rated 5 if there was no practical problem at all, and 1 if there was a problem in practical use. (8) Amount of fallen powder After the test according to (4) above, the amount of fallen powder on the tape sliding surface of the magnetic head was visually observed and evaluated on a five-point scale. The rating was 5 if there was no practical problem at all, and 1 if there was a practical problem. (9) Still Life VHS system VTR (NV-M10, manufactured by Matsushita Electric Co., Ltd.)
was modified, and the still life of each videotape sample in a -10°C environment was measured.

The results obtained are shown in Table 1 and Table 2.

[0032]

[Table 1]

[0033]

[Table 2]

As is clear from Table 1, the present invention is a magnetic recording tape in which a magnetic layer is provided on a non-magnetic support, and the tensile Young's modulus of the magnetic layer is 1500 at -10°C.
~1800Kg/mm2, 110 at 40℃80%RH
0 to 1800 Kg/mm2, further, the tensile Young's modulus of the non-magnetic support in the length direction and the width direction is 600 Kg/mm2 or more, and further, the surface root mean square roughness of the non-magnetic support is 600 Kg/mm2 or more. However, at least one surface is characterized in that the thickness is in the range of 0.01 to 0.025 .mu.m, thereby obtaining a magnetic recording tape having excellent durability and electromagnetic conversion characteristics.

[0035]

As described in detail above, according to the present invention, there is provided a magnetic recording tape in which a magnetic layer is provided on a non-magnetic support, wherein the tensile Young's modulus of the magnetic layer is at -10°C. 15
00~1800Kg/mm2, 1 at 40℃80%RH
100 to 1800 Kg/mm2, further, the tensile Young's modulus of the non-magnetic support in the length direction and the width direction is 600 Kg/mm2 or more, and further, the surface root mean square roughness of the non-magnetic support is 600 Kg/mm2 or more. However, since at least one of the surfaces is in the range of 0.01 to 0.025 μm, it has excellent electromagnetic conversion characteristics such as C/N ratio,
Highly durable magnetic recording with excellent resistance to falling particles, magnetic recording tape deformation, scratches, envelope output flatness, audio level fluctuations, increased dropouts, and deterioration of electromagnetic conversion characteristics, and excellent still life. The tape can be obtained, and its practical value is great.

Claims (3)

[Claims] 1. A magnetic recording tape comprising a magnetic layer provided on a non-magnetic support, the tensile Young's modulus of the magnetic layer being:
1500~1800Kg/mm2 at -10℃, 40℃
A magnetic recording tape characterized in that it has a magnetic field strength in the range of 1100 to 1800 Kg/mm2 at 80% RH. 2. A magnetic recording tape comprising a magnetic layer provided on a non-magnetic support with a thickness of 10 μm or less, wherein the magnetic layer has a tensile Young's modulus of 1500 to 1800 kg at -10°C.
/mm2, 1100-1800K at 40℃80%RH
g/mm2, and the tensile Young's modulus of the non-magnetic support in the length direction and width direction is 600 Kg/m2.
A magnetic recording tape characterized by having a diameter of m2 or more. 3. The surface root mean square roughness of the nonmagnetic support is 0.01 to 0 on at least one surface.
．． 3. The magnetic recording tape according to claim 1, wherein the magnetic recording tape has a diameter in the range of 0.025 μm.