JPH05307731A - Magnetic recording tape - Google Patents

Abstract

(57) [Abstract] [Purpose] Audio output, running durability, tape deformation, audio level fluctuation, D.I. O. To obtain a magnetic recording tape excellent in increase and the like. [Structure] A magnetic layer is provided on one surface of a non-magnetic support,
A magnetic recording tape having a back coat layer on the opposite surface thereof, wherein the temperature is 3 ° C or higher and 40 ° C or lower, and the humidity is 10% RH or higher and 80
In the environmental range of% RH or less, the magnetic recording tape width direction 1
The amount of curvature that makes the magnetic layer side convex per 1/2 inch is
It is in the range of 0.3 mm to 0.7 mm, and the thermal contraction rate after heating for 30 minutes at 105 ° C. in the longitudinal direction of the non-magnetic support is 2.5% or less and the thermal contraction rate in the width direction is the longitudinal direction. Of 1.0
Or more, and at least one of the surface root mean square roughness is in the range of 0.01 to 0.025 μm, and the tensile Young's modulus in the length direction and the width direction is 58.
It is set to 80 MPa or more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording tape for use in video equipment, audio equipment, computers and the like, and more particularly to a thin magnetic recording tape suitable for a long time and its support. Is.

[0002]

2. Description of the Related Art In recent years, these various magnetic recording media have been suitable for high-density recording. Therefore, recording wavelengths are short, recording track widths are narrow, and recording media are thin. As a result, the S / N ratio, sensitivity, and frequency characteristics generally become disadvantageous, but as a countermeasure against this, methods such as making the magnetic powder fine and making the magnetic layer highly smooth are adopted. However, if only the above measures are taken, the surface property of the magnetic layer is increased and the friction coefficient is increased, which is disadvantageous in terms of runnability and durability. It is known to provide a back coat layer on the surface opposite to the surface of the magnetic layer.

[0003]

However, the above-mentioned conventional methods have problems such as durability, especially deformation of the magnetic recording tape, and deterioration of electromagnetic conversion characteristics.

In view of the above problems, the present invention provides a highly durable magnetic recording tape which is excellent in electromagnetic conversion characteristics and is excellent in deformation of the magnetic recording tape and deterioration of electromagnetic conversion characteristics.

[0005]

In order to solve the above problems, the present invention is a magnetic recording tape in which a magnetic layer is provided on one side of a non-magnetic support and a back coat layer is provided on the opposite side. In a temperature range of 3 ° C. or more and 40 ° C. or less and a humidity of 10% RH or more and 80% RH or less, the amount of curvature that makes the magnetic layer side convex per 1/2 inch of the magnetic recording tape width direction is 0.3 mm. It is formed in the range of 0.7 mm. The non-magnetic support used in the present invention has a length of 1
The heat shrinkage ratio after heating at 05 ° C for 30 minutes is 2.5% or less,
The heat shrinkage ratio in the width direction is 1.0 times or more that in the length direction, and the surface root mean square roughness is preferably in the range of 0.01 to 0.025 μm in at least one of the surfaces, and further, When the thickness is thin and 10 μm or less, the tensile Young's modulus in the length direction and the width direction is preferably 5880 MPa or more.

[0006]

According to the present invention, due to the above-described structure, the tape sliding surface of the magnetic head and the condition of the magnetic recording tape with respect to various posts of the running system are improved. In particular, since the heat shrinkage ratio of the non-magnetic support in the width direction is relatively larger than the heat shrinkage ratio in the length direction, it is easy to obtain an appropriate curved state in the tape width direction. Further, the surface property of the non-magnetic support on the side opposite to the magnetic layer side of the magnetic recording tape is shape-transferred to the surface of the magnetic layer to prevent an adverse effect due to the deterioration of the surface property, and thus electromagnetic conversion characteristics, particularly C / N. A magnetic recording tape having an excellent ratio can be obtained. Also, the thickness is 10μ
In the case of a thin film having a thickness of m or less, the tensile Young's modulus in the longitudinal direction and the width direction of the non-magnetic support is limited in order to impart a well-balanced mechanical strength to the magnetic recording tape in a well-balanced manner. It is possible to obtain a highly durable magnetic recording tape that is excellent in deformation, deterioration of electromagnetic conversion characteristics, and the like.

In more detail, for example, in a magnetic recording tape for a video tape recorder, it runs while being wound around a variety of posts at a certain angle, but in order to regulate the position of the various posts in the height direction. Lower regulation posts and upper regulation posts are provided. In order for the tape to run stably without separating from the regulation post, proper running characteristics are required, and when attempting to run with the tape released, it is basically released due to the rigidity of the tape itself. You must drive so that you don't. However, if the thickness of the entire tape becomes thinner, the rigidity of the tape becomes smaller, which is disadvantageous. In addition, the amount of bending that makes the magnetic layer side convex per 1/2 inch in the tape width direction is 0.3 mm to
Outside the range of 0.7 mm, the end face in the tape width direction floats up against various posts in the traveling system, the gap between the post roller part and the regulation part is difficult to crease, and the tape may break, The end part becomes wakame-like, and in the worst case, the tape is broken and important information is lost. Further, the contact state of the magnetic head with respect to the tape sliding surface is not uniform.

As in the present invention, in an environmental range of a temperature of 3 ° C. to 40 ° C. and a humidity of 10% RH to 80% RH,
By setting the amount of curvature in which the magnetic layer side is convex about 1/2 inch in the width direction of the magnetic recording tape to be in the range of 0.3 mm to 0.7 mm, the magnetic head and various posts of the running system are magnetically coupled. Since the recording tape runs in a state of uniformly contacting and being pressed, electromagnetic conversion characteristics, particularly audio output, durability, especially deformation of the tape are greatly improved.

[0009]

The present invention will be described below. Here, as the binder, cross-linking agent, abrasive, optionally added dispersant, plasticizer, antistatic agent, non-magnetic support, back coat layer and the like used in the present invention, those conventionally known may be used. it can.

Hereinafter, the present invention will be specifically described 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".
Is shown.

Example 1 A magnetic coating material was prepared as follows. Fe-based alloy magnetic powder 100 parts [Coercive force H _C = 123.3 × 10 ³ A / m, BET specific surface area = 56 × 10 ³ m ² / kg, Saturation magnetization amount = 1.6 × 10 ^-4 WB · m / Kg, acicular ratio = 9/1] Vinyl chloride vinyl acetate copolymer resin 10 parts Polyurethane resin 10 parts Abrasive (Al ₂ O ₃ ) [average particle size = 0.2 μm] 6 parts Carbon black [average particle size = 20 mμ] 2 parts Myristic acid 1 part Butyl stearate 1 part Methyl ethyl ketone 100 parts Toluene 100 parts Cyclohexanone 60 parts The above composition was kneaded and dispersed using a pressure kneader and a sand mill to prepare a magnetic paint. 4 parts of a polyisocyanate compound [manufactured by Bayer Co., Desmodur L] was added to the obtained magnetic paint, thoroughly mixed and stirred with a high-speed stirrer, and then filtered with a filter having an average pore diameter of 1 μm to prepare the magnetic paint. It was

Next, the above-mentioned magnetic paint having a thickness of 7.5 μm, a tensile Young's modulus in the lengthwise direction of 6670 MPa, a tensile Young's modulus in the widthwise direction of 6080 MPa, a thermal shrinkage of 2 after heating at 105 ° C. for 30 minutes in the lengthwise direction is 2 0.3%, the heat shrinkage ratio in the width direction was 1.3 times that in the length direction, and the surface root mean square roughness was 0.
After coating, magnetic field orientation, and drying treatment on a 012 μm polyethylene terephthalate film support, mirror finishing treatment with a super calender roll was performed to obtain 2.6 μm.
An original roll having a magnetic layer of m thickness was obtained. This raw roll is cured at 50 ° C. for 24 hours, and then a back coat layer having a thickness of 0.5 μm is provided on the opposite surface of the magnetic layer.
Video tape sample (390 m
Long) was prepared.

(Example 2) The thickness of the back coat layer of (Example 1) was changed from 0.5 μm to 0.
A video tape sample was prepared in the same manner as in (Example 1) except that the thickness was changed to 7 μm.

Comparative Example 1 The thickness of the back coat layer of (Example 1) was changed from 0.5 μm to 0.
A video tape sample was prepared in the same manner as in (Example 1) except that the thickness was changed to 9 μm.

(Comparative Example 2) A video tape sample was prepared in the same manner as in (Example 1) except that the raw roll of (Example 1) was subjected to a curing treatment at 50 ° C for 24 hours, without being cured.

(Comparative Example 3) In Example 1, the heat shrinkage rate after heating at 105 ° C. for 30 minutes in the length direction was 2.3% to 2.7%, and the heat shrinkage rate in the width direction was longer. Example 1 except that the polyethylene phthalate film support was changed from 1.3 times the direction to 0.9 times. A video tape sample was prepared in the same manner as in.

(Example 3) The surface root mean square roughness of Example 1 is 0.012μ.
m polyethylene terephthalate film support.
A video tape sample was prepared in the same manner as in (Example 1) except that the thickness was changed to 023 μm.

(Comparative Example 4) The surface root mean square roughness of (Example 1) is 0.012μ.
m polyethylene terephthalate film support.
A video tape sample was prepared in the same manner as in (Example 1) except that the thickness was changed to 027 μm.

(Example 4) The tensile Young's modulus in the length direction is 6670 MPa and the tensile Young's modulus in the width direction is 6080 M in the thickness of 7.5 μm of (Example 1).
A polyethylene terephthalate film support of Pa,
Video tape samples were prepared in the same manner as in (Example 1) except that the polyethylene naphthalate film supports of 7650 MPa and 7160 MPa were replaced.

(Comparative Example 5) The tensile Young's modulus in the lengthwise direction is 6670 MPa and the tensile Young's modulus in the widthwise direction is 6080 M in the thickness of 7.5 μm of (Example 1).
A polyethylene terephthalate film support of Pa,
Video tape samples were prepared in the same manner as in (Example 1), except that the values were changed to 7060 MPa and 5390 MPa, respectively.

The following evaluation tests were carried out on the video tape samples obtained in the above Examples and Comparative Examples. (1) Amount of Curvature Using a Union Optical interference microscope, the amount of curvature of the end face and the center in the width direction of the magnetic recording tape having a width of 1/2 inch was measured. (2) Surface roughness Using a Talystep stylus type surface roughness meter manufactured by Taylor Hobson, longitudinal magnification of 20 × 10 ³ times, lateral magnification of 50 times, stylus 2.5 μm × 0.1 μm, needle pressure 2 mg The surface roughness was measured under the conditions, and the root mean square roughness of the height was calculated and obtained on the roughness chart. (3) C / N ratio C / N at a recording frequency of 7 MHz is used by using an M-Zaformat VTR (AU-650, manufactured by Matsushita Electric Industrial Co., Ltd.) in which an amorphous alloy head is mounted on the recording / reproducing head.
The ratio was measured. As a standard tape, a cassette tape for the M-Zufomat VTR (Matsushita Electric Co., Ltd. AU-M9
0 L) and its C / N ratio was set to 0 dB. (4) Audio output and audio level fluctuation Each video tape sample was used at 40 ° C. 80% with an M-Zaformat VTR (AU-650, manufactured by Matsushita Electric Industrial Co., Ltd.) equipped with an amorphous alloy head as a recording / reproducing head.
A durability test was carried out by running for 200 passes for 300 hours in an RH environment. Before the test, the audio head output (ch. 2) was rectified, and the output was measured for level fluctuation after the test. As the standard tape, a cassette tape for M-Zaformat VTR (AU-M90L manufactured by Matsushita Electric Co., Ltd.) was used, and its audio head output was set to 0 dB. (5) Deformation of tape After the durability test of (3) above, the state of the deformation of the tape sample was visually observed and a five-level evaluation was performed. The evaluation was rated as 5 when there was practically no problem, and as 1 when there was practically a problem. (6) Dropout Dropout counter (manufactured by Shibasoku Co., Ltd., VH01)
BZ). For the dropout, the rate of change after the test with respect to that before the test was shown as a magnification.

The obtained results are shown in (Table 1).

[0023]

[Table 1]

As is clear from (Table 1), according to the present invention, the temperature is 3 ° C. or higher and 40 ° C. or lower, and the humidity is 10% RH or higher and 8 or higher.
In the environmental range of 0% RH or less, the magnetic recording tape width direction 1 /
The amount of curvature in which the magnetic layer side is convex per 2 inches is 0.
In the range of 3 mm to 0.7 mm, the heat shrinkage rate after heating the nonmagnetic support in the lengthwise direction at 105 ° C. for 30 minutes is 2.5% or less, and the heat shrinkage rate in the width direction is 1 in the lengthwise direction. Is 0.0 times or more, and at least one of the surface root mean square roughness is in the range of 0.01 to 0.025 μm,
And, the tensile Young's modulus in the length direction and the width direction is 5880
When the pressure is higher than MPa, the magnetic output has excellent electromagnetic conversion characteristics such as audio output, and is highly durable against deformation of the magnetic recording tape, audio level fluctuation, increase in dropout, and deterioration of electromagnetic conversion characteristics. You get the tape.

[0025]

As described above in detail, according to the present invention, the temperature is 3 ° C. or higher and 40 ° C. or lower, and the humidity is 10% RH or higher and 80% or higher.
1/2 in the magnetic recording tape width direction in the environmental range of% RH or less
The amount of curvature that makes the magnetic layer side convex per inch is 0.3.
It is in the range of 0.7 mm to 0.7 mm, and the heat shrinkage ratio after heating the nonmagnetic support in the longitudinal direction at 105 ° C. for 30 minutes is 2.
5% or less, the heat shrinkage ratio in the width direction is 1.0 times or more in the length direction, and the surface root mean square roughness is at least one of the surfaces is in the range of 0.01 to 0.025 μm,
And, the tensile Young's modulus in the length direction and the width direction is 5880
By setting the pressure to MPa or more, excellent electromagnetic conversion characteristics such as audio output and excellent durability against deformation of the magnetic recording tape, audio level fluctuation, increase in dropout, deterioration of electromagnetic conversion characteristics, etc. A magnetic tape can be obtained, and its practical value is great.

Claims (4)

[Claims] 1. A magnetic recording tape having a magnetic layer on one surface of a non-magnetic support and a back coat layer on the other surface, the temperature being 3 ° C. to 40 ° C. and the humidity being 10% RH to 80. The magnetic recording tape is characterized in that, in an environmental range of not more than% RH, the amount of curvature that makes the magnetic layer side convex per 1/2 inch in the width direction of the magnetic recording tape is in the range of 0.3 mm to 0.7 mm. .. 2. A nonmagnetic support in the longitudinal direction at 105 ° C., 30
The heat shrinkage after heating for a minute is 2.5% or less, and the heat shrinkage in the width direction is 1.0 times or more in the length direction. Magnetic recording tape. 3. The surface root mean square roughness of the non-magnetic support is 0.01 to 0.02 on at least one of the surfaces.
Claims characterized by being in the range of 5 μm
The magnetic recording tape according to item (1). 4. The non-magnetic support has a thickness of 10 μm or less and a tensile Young's modulus of 5 in the length direction and the width direction.
The magnetic recording tape according to claim 1, wherein the magnetic recording tape has a pressure of 880 MPa or more.