JP2000016644A - Thermoplastic resin film roll - Google Patents

Abstract

PROBLEM TO BE SOLVED: To hold a superior winding form in winding up a product for a long time, to improve blocking resistance, and reduce the peeling charge quantity even if winding hardness is increased by specifying the surface roughness of respective center lines of both faces of a film and the winding hardness of the film roll. SOLUTION: Biaxial orientation polyester film is slit into a desired film width so as to be wind up into a roll. In this case, for example, the contact pressure of a rubber roll is adjusted so that the winding hardness of the film roll become no less than 90 deg. but no more than 98 deg. in Asker hardness. As for the film, one of a center line surface roughness RaA is set to 10 nm or less. The other center line surface roughness RaB is set to 20 nm or less. When the surface roughnesses RaA, RaB of the both surfaces of the film are different, the film as a form of a laminated film. Therefore, it has less peeling charge and superior blocking resistance so that it is suited for a base film for a magnetic record medium, especially high-density magnetic record medium.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a magnetic recording medium having a small amount of peeling electricity, good blocking resistance and good winding, and particularly suitable for use as a base film of a high-density magnetic recording medium. The present invention relates to a film roll of a plastic resin film.

[0002]

2. Description of the Related Art In recent years, remarkable progress has been made in increasing the density of magnetic recording media. For example, a metal thin film in which a ferromagnetic metal thin film is formed on a non-magnetic support by a physical deposition method such as vacuum evaporation or sputtering or a plating method. The development and commercialization of a thin-film magnetic recording medium in which a needle-like magnetic powder such as a metal powder or an iron oxide powder is applied to a thickness of 2 μm or less, are also being promoted.

Examples of the former include, for example, Co-deposited tape (Japanese Patent Laid-Open No. 54-147010), Co-Cr
Perpendicular magnetic recording medium made of an alloy (Japanese Patent Laid-Open No. 52-1347)
No. 06 publication) is known. As the latter example, for example, high-density magnetic recording using an ultra-thin layer coating type medium [Technical Report of the Institute of Electronics and Communication Engineers MR94-78 (1995-02)] is known.

Conventional coating type magnetic recording media (magnetic recording media in which magnetic powder is mixed with an organic polymer binder and coated on a nonmagnetic support) have a low recording density and a long recording wavelength. While the thickness of the magnetic layer is as thick as about 2 μm or more, the metal thin film formed by thin film forming means such as vacuum evaporation, sputtering, or ion plating has a very small thickness of 0.2 μm or less, and is extremely thin. In the case of a layer coating type medium as well, although a non-magnetic underlayer is provided.
It is very thin with a thickness of 13 μm.

Therefore, in the above-described high-density magnetic recording medium, the surface condition of the non-magnetic support greatly affects the surface properties of the magnetic layer. The surface state of the support is directly expressed as irregularities on the surface of the magnetic layer, which causes noise in the reproduced signal. Therefore, it is desirable that the surface of the non-magnetic support is as smooth as possible.

For this reason, only the surface of the non-magnetic layer side of the non-magnetic support is co-extruded or coated.
A technique of roughening by laminating a filler-containing layer is used.

However, with the increase in the density of magnetic recording, the surface roughness of the non-magnetic layer side of the non-magnetic support is transferred to the surface of the magnetic layer.
Since O and the like are generated, the surface on the nonmagnetic layer side is also being flattened. For this reason, at the time of winding the product film, it is conceivable that the product film is hard-wound so as to reduce the temporal change of the winding shape. On this occasion,
There is a problem that the peeling charge is increased by increasing the winding hardness.

In order to reduce the charge, conventionally, a method of mixing an antistatic agent into a polymer or applying an agent having an antistatic function by coating has been proposed. In a conventional magnetic recording medium, the conventional method causes defects such as dropout (D / O) due to bleed out of the antistatic agent.

Further, the inventor of the present invention has found that even when the end face of the film has a high edge due to the decrease in the surface roughness of the non-magnetic support, the high edge portions are blocked when wound into a roll. Problem occurs.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to overcome the drawbacks of the prior art and to use it as a base film of a magnetic recording medium having a small peeling charge and good blocking resistance, especially a high density magnetic recording medium. It is to provide a thermoplastic resin film roll suitable for the above.

[0011]

The present invention has the following configuration to achieve the above object.

That is, a thermoplastic resin film is wound into a roll, and the film has a center line surface roughness (RaA) of 10 nm or less on one surface and the other center line surface roughness. (RaB) is 20 nm or less, and the roll hardness of the roll is 90 ° or more and 98 ° or less in Asker hardness (measured using “ASKER rubber hardness tester” manufactured by Kobunshi Keiki Co., Ltd.). Characteristic thermoplastic resin film roll.

In this case, it is preferable that the peeling charge amount is 40 KV or less.

The roll hardness of the film roll of the present invention is 90 ° to 98 °, preferably 92 ° to 97 ° in Asker strength. If the Asker hardness is less than 90 °, the end face will shift during transport of the roll, causing problems such as poor shape or scratching.In the production of a metal thin film magnetic recording medium,
When putting in a vacuum chamber, which is the process of forming a metal thin film,
If the Asker hardness is less than 90 °, buckling occurs at the core due to a large air layer, which is not preferable. On the other hand, when the Asker hardness exceeds 98 °, the charge amount of the film increases and static electricity is generated, which deteriorates the handleability of the film and is dangerous for use in a process using an organic solvent. Similarly, if the charge amount exceeds 40 KV, a problem occurs.

Further, in the film roll of the present invention, the wound thermoplastic resin film has an end parallel to the longitudinal direction of the film oscillated, and the surface roughness of the roll end face is not less than 3 μm and not more than 200 μm. Preferably, there is.

The surface roughness of the end face of the film roll in the present invention is preferably 3 μm or more and 200 μm or less, more preferably 5 to 200 μm, particularly preferably 5 to 100 μm, and particularly preferably 10 to 100 μm. If the surface roughness of the roll end face is less than 3 μm, high pressure is locally applied at the high edge portion of the film, causing blocking between the films and causing process troubles such as film cutting. On the other hand, when the surface roughness exceeds 200 μm,
The shape of the roll is poor, which is not preferable.

The end face of the film roll has an unevenness depth of 0.050 mm or more and 5 mm or less,
It is preferably 1 mm or more and 5 mm or less. Further, it is preferable that an apex interval (an interval between two adjacent apexes) of the convex portions of the unevenness on the end face of the roll in the roll diameter direction is 0.2 mm or more and 1 mm or less.

Examples of the thermoplastic resin in the present invention include polyester resins, polyamide resins, polyimide resins, polyether resins, polycarbonate resins, polyvinyl resins, and polyolefin resins. Of these, polyester-based resins, and aromatic polyesters are preferred.

As the aromatic polyester, polyethylene terephthalate, polyethylene isophthalate,
Preferred examples include polytetramethylene terephthalate, poly-1,4-cyclohexylene dimethylene terephthalate, and polyethylene-2,6-naphthalenedicarboxylate. Of these, polyethylene terephthalate and polyethylene-2,6-naphthalenedicarboxylate are particularly preferred.

The polyester may be a homopolyester or a copolyester. In the case of copolyester, for example, as a copolymer component of polyethylene terephthalate and polyethylene-2,6-naphthalenedicarboxylate, for example, diethylene glycol,
Propylene glycol, neopentyl glycol, polyethylene glycol, p-xylylene glycol, 1,
Diol components such as 4-cyclohexanedimethanol, adipic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid (however, in the case of polyethylene-2,6-naphthalenedicarboxylate), 2,6-naphthalenedicarboxylic acid (however, , Polyethylene terephthalate), other dicarboxylic acid components such as 5-sodium sulfoisophthalic acid, and oxycarboxylic acid components such as p-oxyethoxybenzoic acid. Incidentally, the amount of the copolymer component is preferably 20 mol% or less, more preferably 10 mol% or less. Further, trifunctional or higher polyfunctional compounds such as trimellitic acid and pyromellitic acid can be copolymerized. In this case, the polymer is preferably copolymerized in a substantially linear amount, for example, 2 mol% or less.

The film made of polyester or the like used in the present invention can optionally contain additives such as a stabilizer, a colorant and an antistatic agent. In particular, in order to roughen the film surface and improve the slipperiness, it is preferable to mix various inert solid fine particles in the polymer.

The biaxially oriented polyester film, which is one of the thermoplastic resin films used in the present invention, is obtained, for example, by melting a sufficiently dried polyester at a melting point of (melting point + 7
0) Melt extrusion at a temperature of 0 ° C., rapid cooling on a casting drum to form an unstretched film, and then sequentially or simultaneously biaxially stretch the unstretched film and heat-set it. Biaxial stretching is preferably sequential biaxial stretching,
At that time, the unstretched film is stretched 2.3 to 6.5 times in the longitudinal direction at 70 to 170 ° C, and then stretched 2.3 to 6.5 times in the transverse direction at 70 to 150 ° C using a stenter. 1
It is preferred to heat set at a temperature of 50 to 250 ° C. under tension or limited shrinkage. The heat setting time is preferably from 10 to 30 seconds. The stretching conditions in the longitudinal and transverse directions are preferably selected so that the properties of the obtained biaxially oriented polyester film satisfy the required properties, for example, such that the properties in both directions are substantially equal. In the case of simultaneous biaxial stretching, the above stretching temperature, stretching ratio, heat setting temperature and the like can be applied.

If necessary, a so-called three-stage stretching method or a four-stage stretching method in which the biaxially stretched polyester film is further stretched in the machine direction and / or the transverse direction can be employed. In the four-stage stretching method, the unstretched film is 70 to
The film is stretched 1.8 to 2.8 times in the longitudinal direction at a temperature of 150 ° C., and then stretched 3.5 to 5 times in the transverse direction with a stenter, and then heat-set at a temperature of 100 to 170 ° C. for 10 to 30 seconds ( (Intermediate heat fixation), and then re-stretched 1.5 to 3.0 times in the longitudinal direction at a temperature of 110 to 180 ° C.
The film may be stretched 1.2 to 2.4 times in the transverse direction at a temperature of 0 to 190 ° C, and may be heat-set under tension at a temperature of 150 to 250 ° C for 10 to 30 seconds.

The biaxially stretched film thus obtained is slit into a desired film width, and then wound into a roll.
At this time, the winding hardness of the film roll is 90 as Asker hardness.
The contact pressure of a contact pressure roll of a winding machine, for example, a rubber roll, is adjusted so as to be not less than 98 ° and not more than 98 °. Further, it is preferable to oscillate the wound film so that the roll end face of the film roll has a surface roughness of 3 to 200 μm.

The thermoplastic resin film of the present invention, particularly the biaxially stretched polyester film, has a center line surface roughness (RaA) of one surface of 10 nm or less, preferably 5 n.
m or less. The lower limit of the center line surface roughness (RaA) is preferably 0.3 nm, more preferably 0.5 nm. Also, the center line surface roughness of the other surface (Ra
B) is 20 nm or less, preferably 10 nm or less.
The lower limit of the center line surface roughness (RaB) is preferably 1 nm, more preferably 3 nm.

When the surface roughness RaA and RaB of both surfaces of the thermoplastic resin film are different, the film takes the form of a laminated film. This laminated film can be formed by a conventionally known lamination method, for example, a coextrusion method or a coating method. For example, in the co-extrusion method, a polymer containing a predetermined particle size and amount of inert fine particles (lubricant) and a polymer containing no such fine particles or having a smaller particle size and / or
Alternatively, it can be obtained by co-extruding a polymer containing a small amount of inert fine particles in a molten state to form an unstretched laminated film, and then stretching the unstretched laminated film biaxially. In the coating method, when producing a biaxially stretched film using a polymer that does not contain inert fine particles, it can be produced by coating an unstretched film or a uniaxially stretched film with a coating liquid containing inert fine particles. it can.

The thermoplastic resin film according to the present invention comprises:
The thickness (total thickness) is 2.5 to 10 μm, and further 3 to 8 μm
m is preferable.

The film roll of the present invention has the above-mentioned winding hardness, but has the advantage that the amount of peeling charge is small. The peeling charge amount is 40 KV or less, and furthermore, 20
It is preferably at most KV. This advantage is advantageous when a thermoplastic resin film is used for a base film of a magnetic recording medium.

When the film roll of the present invention is used for producing a magnetic recording medium, for example, the embodiment is as follows.

On a smooth surface (surface having a surface roughness of RaA) of the film rewound from the film roll of the present invention, iron, cobalt, chromium, or these are coated by a method such as vacuum deposition, sputtering, or ion plating. A ferromagnetic metal thin film layer composed of an alloy or oxide as a main component is formed, and a protective layer such as diamond-like carbon (DLC) or a fluorinated carboxylic acid-based layer is formed on the surface of the ferromagnetic metal thin film. By providing a lubricating layer sequentially and, if necessary, providing a back coat layer on the surface on the thin film layer C side by a known method, the output in the short wavelength region, S /
Excellent electromagnetic conversion characteristics such as N, C / N, dropout,
A vapor-deposited magnetic recording medium for high-density recording with a low error rate can be obtained. This vapor-deposited magnetic recording medium is extremely useful as a Hi8 for analog signal recording, a digital video cassette recorder (DVC) for digital signal recording, an 8 mm data, and a DDSIV tape medium.

In the film unwound from the film roll of the present invention, iron or fine needle-like magnetic powder (metal powder) mainly composed of iron is coated on a smooth surface with polyvinyl chloride, vinyl chloride / vinyl acetate copolymer. It is uniformly dispersed in a binder such as a coalescence, and has a magnetic layer thickness of 1 μm or less, preferably 0.1 to 1 μm.
m, and further, if necessary, by providing a back coat layer on the rough surface by a known method,
In particular, a metal-coated magnetic recording medium for high-density recording with excellent output in the short wavelength region, electromagnetic conversion characteristics such as S / N, C / N, and low dropout and error rate can be obtained. Further, if necessary, a nonmagnetic layer containing fine titanium oxide particles or the like as an underlayer of the metal powder-containing magnetic layer is dispersed in the same organic binder as the magnetic layer on the smooth surface,
It can also be painted. This metal-coated magnetic recording medium includes 8 mm video for recording analog signals, Hi8, β cam SP, W-VHS, digital video cassette recorder (DVC) for recording digital signals, 8 mm data, and D
It is extremely useful as a magnetic tape medium for DSIV, digital β cam, D2, D3, SX, etc.

The film unwound from the film roll of the present invention may be provided on a smooth surface with needle-like fine magnetic powder such as iron oxide or chromium oxide, or plate-like fine magnetic powder such as barium ferrite. Evenly dispersed in a binder such as vinyl / vinyl acetate copolymer, and the magnetic layer thickness is 1
μm or less, preferably 0.1 to 1 μm, and further, if necessary, by providing a back coat layer on the rough surface by a known method, especially in the short wavelength region, so that the output, S / N And an oxide-coated magnetic recording medium for high-density recording, which has excellent electromagnetic conversion characteristics such as C / N and low dropout and error rate. Further, if necessary, a nonmagnetic layer containing fine titanium oxide particles or the like is dispersed in the same organic binder as the magnetic layer and coated as a base layer of the magnetic powder-containing magnetic layer on the smooth surface. You can also. This oxide-coated magnetic recording medium is extremely useful as a high-density oxide-coated magnetic recording medium such as a data streamer QIC for digital signal recording.

The above-mentioned W-VHS is an analog HDTV signal recording VTR, and DVC is a digital HTV signal.
The film of the present invention is applicable to DTV signal recording, and can be said to be a very useful base film for these HDTV-compatible VTR magnetic recording media.

[0034]

EXAMPLES The present invention will be described more specifically with reference to the following examples, but the present invention is not limited to these examples. In the Examples and Comparative Examples, “parts” and “%” are based on weight unless otherwise specified, and the physical property values and properties in the present invention are measured and defined by the following methods, respectively, and are defined. is there.

[Asker hardness] It is represented by an average value obtained by observing 10 points in the roll width direction using an ASKER rubber hardness meter type C manufactured by Kobunshi Keiki Co., Ltd.

[Electrification Amount of Peeling] Rolled film
m / min, rewinding and stripping off, using a current collector type potential measuring device manufactured by Kasuga Electric Co., Ltd., trade name "KS-525 type"
The maximum value when the charge amount is measured in the longitudinal direction is defined as the peeling charge amount.

[Evaluation of Blocking] After leaving the roll-shaped film at 80% relative humidity and a temperature of 60 ° C. for 3 days, the film was rewound at a speed of 100 m / min, peeled off, and cut at the end face by blocking. evaluate. ：: No disconnection. ×: There is disconnection.

[Center Line Surface Roughness of Film Surface] (Ra
A, RaB) Non-contact three-dimensional roughness meter manufactured by WYKO Co., Ltd., trade name "TO
PO-3D ", measuring magnification 40 times, measuring area 24
The measurement is performed under the condition of ² μm × 239 μm (0.058 mm ² ), and Ra is calculated by the following formula by surface analysis using built-in software of the roughness meter, and an output value is used.

[0039]

(Equation 1)

Z _jk is the height on the three-dimensional roughness chart at the j-th and k-th positions in the measurement direction (242 μm) and the direction orthogonal to it (239 μm) divided into M and N, respectively. It is.

[Roll shape under reduced pressure] The roll-shaped film was left under a reduced pressure of 100 mmHg for 8 hours, then returned to normal pressure, and evaluated for buckling of the core. ：: No buckling. ×: There is buckling.

[Surface Roughness of Roll End Surface] A curable silicone resin manufactured by Toyo Chemical Laboratory Co., Ltd., trade name "DE-SI-CON" was mixed with a special hardener at any five locations on the roll end surface. A replica is sampled with a tool, and the sampled replica is cut in parallel with the roll diameter direction, and the cut surface is observed with a microscope. The length (Lx) in the roll diameter direction is 1 to
Take a picture so that it is 5 mm.

When the photographed image is subjected to image processing using an image processing analyzer manufactured by Nireco Co., Ltd., trade name “LEX-FS”, and the obtained center line roughness is represented by z = f (x), The value obtained by the following equation is defined as the film surface roughness.

[0044]

(Equation 2)

[Depth of unevenness and vertex interval on end face of film roll] The method of measuring the depth of unevenness on the end face of the film roll and the apex distance between convex portions is the same as in the above [Surface roughness]. Is cut in parallel with the roll diameter direction, and a photograph is taken so that the length (Lx) in the roll diameter direction is 5 mm, and the 5-point average value of the maximum depth in Lx is defined as the depth of unevenness on the end face. I do.

The average value of the five points which is the minimum distance between adjacent peaks (vertices) separated by 0.1 mm or more is defined as the vertex distance.

Example 1 Dimethyl terephthalate and ethylene glycol were polymerized in the usual manner by adding manganese acetate as a transesterification catalyst, antimony trioxide as a polymerization catalyst, and phosphorous acid as a stabilizer.
Polyethylene terephthalate A substantially free of inert fine particles was obtained.

In the same manner, polyethylene terephthalate B containing 0.15% of silica particles having an average particle diameter of 0.4 μm was obtained.

Each of these polyethylene terephthalates was dried at 170 ° C. for 3 hours, and then supplied to two extruders, respectively, and melt-extruded at a melting temperature of 290 ° C. using a multi-manifold type co-extrusion die. The sheet extruded from the die was rapidly cooled to obtain an unstretched film having a thickness of 82 μm.

The obtained unstretched film is preheated, stretched 3.2 times in the machine direction at a film temperature of 95 ° C. between low-speed and high-speed rolls, quenched, and then cooled to the polyethylene terephthalate A side of the vertically-stretched film temperature. A water-soluble coating solution containing a water-soluble resin of an acrylic-modified polyester and acrylic particles having an average particle diameter of 30 nm is 0.005 μm (0.0% after stretching and drying).
15 μm), and then supplied to a stenter and stretched 4.1 times in the horizontal direction at 110 ° C.
The obtained biaxially stretched film was heat-set with hot air at 220 ° C. for 5 seconds to obtain a laminated biaxially oriented polyester film having a thickness of 5.9 μm.

The surface roughness RaA of the obtained polyethylene terephthalate A is 1.5 nm, and the surface roughness RaB of the polyethylene terephthalate B is 4.2 nm.

The polyester film thus obtained was wound on a rubber roll having an Asker hardness of 50 degrees with a contact pressure of 50 kg / m and a width of 500 mm and a length of 8,000 m.

At this time, the roll end face was film-oscillated so that one side satisfies the following formula (1) ′, and the opposite end moved in accordance with this.

[0054]

(Equation 3)

However, the unit is millimeter (mm).

Y: Displacement of the film edge when the position of the innermost film edge of the oscillation is defined as a reference 0, and the outside of the oscillation is defined as plus. X: Arbitrary position in the longitudinal direction of the film (however, This is the displacement of the end in the longitudinal direction of the film when the oscillation is shifted from the innermost position to the outermost position (reference 0), and the oscillation period is 50 m.

The Asker hardness of the obtained roll, the charge amount,
The surface roughness of the roll end face is as shown in Table 1.

Comparative Example 1 A biaxially oriented polyester film similar to that of Example 1 was applied to a rubber roll having an Asker hardness of 50 degrees at a contact pressure of 20 kg / m, a width of 500 mm and a length of 8,000.
0 m was wound under the same conditions as in the oscillation of the roll end face in Example 1.

The properties of the obtained roll are as shown in Table 1.

Comparative Example 2 In Comparative Example 1, the contact pressure was set to 8
The test was performed under the same conditions as in Comparative Example 1 except that the pressure was 0 kg / m.

The properties of the obtained roll are as shown in Table 1.

Comparative Example 3 Dimethyl terephthalate and ethylene glycol were added, manganese acetate was added as a transesterification catalyst, antimony trioxide was added as a polymerization catalyst, and phosphorous acid was added as a stabilizer.
Polyethylene terephthalate C containing 0.10% of silica particles having an average particle size of 0.6 μm was obtained.

The polyethylene terephthalate was converted to 170
After drying at ℃ for 3 hours, the mixture was melt-extruded from a die at a melting temperature of 290 ° C. The sheet material melt-extruded from the die was quenched to obtain an unstretched film having a thickness of 82 μm.

The obtained unstretched film was preheated, stretched 3.2 times in the machine direction at a film temperature of 95 ° C. between low-speed and high-speed rolls, quenched, and then supplied to a stenter.
The film was stretched 4.1 times in the transverse direction at 110 ° C. The obtained biaxially stretched film was heat-set with hot air at 220 ° C. for 5 seconds to obtain a biaxially oriented polyester film having a thickness of 5.9 μm.

The surface roughness Ra of the obtained film was 18 nm on both sides.

This film was wound under the same conditions as in Comparative Example 1 except that the contact pressure was 100 kg / m.

The properties of the obtained roll are as shown in Table 1.

[0068]

[Table 1]

As is evident from Table 1, the product according to the present invention has a small amount of peeling charge even when the winding hardness is high, the winding appearance during winding of the product is good for a long time, and the anti-blocking property is also high. It shows excellent properties.

[0070]

The thermoplastic resin film of the present invention is excellent in the winding property and the flatness of the non-magnetic layer surface required as a base film for magnetic recording. It has a good winding shape for a long period of time, has excellent blocking resistance, and has a characteristic that the amount of peeling charge is small even when the winding hardness is increased, so it is particularly useful for high density magnetic recording media. .

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshifumi Osawa 3-37-19 Koyama, Sagamihara-shi, Kanagawa F-term in the Sagamihara Research Center, Teijin Limited 3F055 AA05 4F071 AA14 AA45 AA46 AA50 AA51 AA54 AA60 AF13Y AF27Y AF38Y AF53 AF54 AH14 BA01 BB06 BB08 BC01 BC16 5D006 BA19 CB01 CB07 FA00

Claims (11)

[Claims] 1. A film roll in which a thermoplastic resin film is wound into a roll, wherein a center line surface roughness (RaA) of one surface of the film is 10 nm or less, and a center line of the other surface is A thermoplastic resin film roll having a surface roughness (RaB) of 20 nm or less and a winding hardness of the film roll of 90 ° or more and 98 ° or less in Asker hardness. 2. The thermoplastic resin film roll according to claim 1, wherein the peeling charge amount is 40 KV or less. 3. The thermoplastic resin film according to claim 1, wherein the center line surface roughness (RaA) of one surface is 5 nm or less and the center line surface roughness (RaB) of the other side is 10 nm or less. 3. The thermoplastic resin film roll according to item 1. 4. The thermoplastic resin film according to claim 1, wherein the end of the film roll parallel to the longitudinal direction of the film is oscillated, and the surface roughness of the end face of the roll is 3 μm or more and 200 μm or less. roll. 5. The depth of the unevenness of the roll end surface is 0.056 m.
5. The thermoplastic resin film roll according to claim 1, having a length of not less than m and not more than 5 mm. 6. The thermoplastic resin film according to claim 1, wherein a distance between two adjacent vertexes in the roll diameter direction of the convex portion of the concave and convex portions on the roll end surface is 0.2 mm or more and 1 mm or less. roll. 7. The thermoplastic resin film roll according to claim 1, wherein the total thickness of the film is 2.5 to 10 μm. 8. The thermoplastic resin film roll according to claim 1, which is used for a base film of a magnetic recording medium. 9. The thermoplastic resin film roll according to claim 8, wherein the magnetic recording medium is a metal thin film type magnetic recording medium. 10. The magnetic recording medium according to claim 1, wherein the thickness of the magnetic layer is 1 μm.
The thermoplastic resin film roll according to claim 8, which is the following coating type magnetic recording medium. 11. The thermoplastic resin film roll according to claim 8, wherein the magnetic recording medium is a digital signal recording type magnetic recording medium.