JP6565742B2 - Plastic film roll for magnetic recording materials - Google Patents

Description

  The present invention relates to a plastic film roll capable of uniformly applying a coating liquid for magnetic recording tape.

  Plastic films are used as base films for magnetic recording tapes, and in recent years, the demand for magnetic recording tapes is increasing for backup and archiving applications in cloud computing and ICT (Information and Communication Technology). . In addition, since the amount of data to be stored has increased dramatically due to the handling of big data, a highly reliable and high-density recording technique has been pursued. For the base film of magnetic recording tape, in order to meet the demand for higher density, extreme pursuit for a smooth surface with uniform thickness unevenness is being pursued.

  However, due to unevenness in the thickness of the base film and air entrainment between layers, the film may be deformed due to the influence during roll storage, or air between layers may escape and cause sagging of the film. When such a film is applied to the tape, uneven thickness of the coating solution occurs in the slack area, and when slitting to the tape width, the length of the tape end varies in the width direction and is curved (deterioration of tape curvature) ).

  Therefore, coating processing manufacturers have also changed the tension balance so that the thickness unevenness of the raw material does not affect the coating (Patent Document 1), or stopped using the portion with the poor original shape of the edge (Patent Document 2). . However, these methods are corrections for coating unevenness with respect to the entire width of the base film. In order to correct the uneven coating thickness at the width level of a magnetic tape product of about 10 mm in width, or to achieve high demand performance and improved tape manufacturing yield in recent years. It is insufficient.

JP 2004-269113 A JP 2009-243964 A

  Accordingly, an object of the present invention is to provide a plastic film that is less likely to sag during roll storage and has excellent tape processability.

  In order to solve this problem and achieve the above object, the present invention has the following configuration.

(1) A plastic film roll for a magnetic recording material in which a film is wound on a cylindrical core, and the roll average diameter D is 200 mm or more and 500 mm or less, and the roll is measured every 0.5 mm in the width direction. In the case of the shape values G1, G2, G3,... GX (mm), the value of the larger roll diameter is Gh (mm) and the value of the smaller one is Gl (mm) in all adjacent measurement value pairs. ,
(Gh−Gl) /0.5 <tan (0.3 °)
The plastic film roll for magnetic recording materials which has the original fabric shape value satisfy | filling the relationship which becomes.

  (2) The plastic film roll for magnetic recording materials according to (1), wherein the surface roughness Ra of the surface on which the magnetic layer of the film is formed is 0.5 nm or more and 20 nm or less.

  (3) The plastic film roll for magnetic recording materials according to (1) or (2), wherein the air biting rate is 0.5% or more and 25% or less.

  (4) The plastic film roll for magnetic recording materials according to any one of (1) to (3), wherein the film has a thickness of 1 μm or more and 20 μm or less.

  (5) The plastic film roll for magnetic recording materials according to any one of (1) to (4), wherein the thickness unevenness of the film is 9% or less of the average film thickness t.

  (6) The plastic film roll for magnetic recording materials according to any one of (1) to (5), wherein a dimensional change rate after the film is treated at 100 ° C. is 0% or more and 2% or less.

  By applying the present invention, as described later, it is possible to provide a plastic film that is less likely to sag during roll storage and has excellent tape processability.

  In the present invention, the plastic film roll is obtained by winding a film such as a polyester film, an aromatic polyamide film, a polypropylene film, a nylon film, or a polycarbonate film around a cylindrical core. Of course, the film to be rewound is not limited to these.

  The plastic film roll of the present invention can be suitably used for a magnetic recording material. Here, examples of the magnetic recording material include materials used for data storage tapes used in enterprise systems and LTO (Linear Tape-Open).

Examples of the cylindrical core include a cylinder for winding a film made of fiber reinforced plastic (FWP), carbon, paper, or the like. In particular, it is preferable to use a cylindricity of less than 0.1 mm and a Shore hardness of 85 degrees or more.
The cylindricity is the difference between the maximum value and the minimum value of the data values measured in the same manner with an original fabric shape measuring instrument described later. Shore hardness means the average value of 10 points measured at equal intervals in the width direction using a Shore hardness meter with a load of 1 kg according to JISK-6253 (2012) (cylindrical core 10 mm at each end is excluded from the measurement range).

  In addition, particles can be added to the film for surface formation. Examples of the types of particles include, but are not limited to, silica particles, calcium carbonate particles, carbon particles, polycarbonate particles, polyester particles, and polyether sulfone particles.

  The roll average diameter D of the plastic film roll of the present invention is preferably 200 mm or more and 500 mm or less.

Moreover, in the original fabric shape values G1, G2, G3,..., GX (mm) obtained by measuring the roll every 0.5 mm in the width direction, the value of the larger roll diameter is set to Gh ( mm) and the smaller value is Gl (mm),
(Gh−Gl) /0.5 <tan (0.3 °)
It is preferable to have a raw fabric shape value that satisfies the following relationship.

  When the value of (Gh−G1) /0.5 is tan (0.3 °) or more, even if the coating liquid is evenly applied, the coating liquid flows in the Gl direction, and the coating thickness is not uniform. , May be curved when slitting to tape width. When the roll average diameter D is less than 200 mm, coating unevenness may occur even if the above relational expression is satisfied. In addition, it is difficult to wind so that the average diameter D exceeds 500 mm in applications for magnetic tape where smoothness is required, and even if the film is wound up, the amount of lamination of the film is different. The effect is thin.

  In the plastic film roll of the present invention, the surface roughness Ra of the surface on which the magnetic layer of the film is formed is desirably 0.5 nm or more and 20 nm or less. If the thickness is less than 0.5 nm, the slippage between the films may be deteriorated, and wrinkles or the like may be involved, or the adhesiveness of the applied liquid may be deteriorated. On the other hand, if the thickness exceeds 20 nm, there is a risk that the coating liquid for magnetic recording material cannot be uniformly coated.

  In the plastic film roll of the present invention, it is desirable that the air entrapment ratio contained between the films is 0.5% or more and 25% or less. If the air entrapment rate exceeds 25%, air may escape during storage of the film roll, and the film may become slack, or may be bent when slitting to the tape width. If it is less than 0.5%, the slippage between the films is poor and wrinkles may be involved.

  The thickness of the film in the present invention is desirably 1 μm or more and 20 μm or less. If it is less than 1 μm, handling may be difficult and may not be suitable for processing. Also, a film exceeding 20 μm may not be suitable as a film for magnetic tape that requires a thin film.

  The thickness unevenness of the film in the present invention is desirably 9% or less of the thickness average value. If it exceeds 9%, the sag of the film may increase, or it may be difficult to satisfy the conditional expression (Gh−Gl) /0.5 <tan (0.3 °).

  The dimensional change rate at 100 ° C. of the film in the present invention is preferably 0% or more and 2% or less. When the rate of dimensional change becomes negative or exceeds 2%, there is a possibility of shrinkage during processing of the magnetic tape and uneven coating.

  Hereinafter, although the manufacturing method of the plastic film roll of this invention is demonstrated, this invention is not limited to this.

  The method for forming the plastic film roll of the present invention is not particularly limited, and any method such as melt film formation or solution film formation may be used.

(Raw material preparation process)
As described above, particles can be added to the plastic film roll of the present invention. The particles to be added preferably have a primary particle size of 1 nm or more and less than 1,000 nm and a content of 0.0 mass% or more and less than 10 mass%. If the particle size is 1,000 nm or more or the content is 10% by mass or more, it may be difficult to achieve the above-described surface roughness and air entrainment rate.

(Extrusion process)
The base used for obtaining the film may be combined with any of a general T die, I die, coat hanger die, and fish tail die. In addition, as an adjustment mechanism, a manual method using a screw bolt, a mechanical method in which the screw is driven by a motor, a heat bolt method using the thermal expansion of the rod, etc. may be used. It is preferable to use an automatic thickness control base that performs feedback control based on a thickness meter measurement result or a raw fabric shape measurement result. The automatic thickness control die has a pair of lips forming a slit gap, and the polymer is discharged through a die provided with a plurality of slit gap adjustment bolts arranged along the slit width direction on one lip. A program is activated by inputting the target thickness of the full width of the product and the slit gap adjusting bolt automatically moves is called an automatic cap bolt.

In achieving the original fabric shape defined in the present invention, it is desirable that the automatic base bolt control be programmed so that the following equation is established.
(Y0-Y1) / (αβ) / X <tan (0.3 °)
Film longitudinal direction (film forming direction, hereinafter referred to as MD) Stretch ratio: α, Film width direction (direction orthogonal to MD direction on the film surface, hereinafter referred to as TD) Stretch ratio: β, between automatic bolts in TD direction Distance: X (mm), movement amount in the bolt thickness direction: Y (mm) (when the movement amount of a bolt is Y0, the movement amount of the adjacent bolt is Y1)
By performing this programming, there is no steep pressure difference between adjacent bolts, and a steep original shape displacement profile difference between the bolts can be reduced.

(Stretching process)
The plastic film of the present invention is preferably a biaxially stretched film, and the method for biaxial stretching of the film may be either a sequential biaxial stretching method or a simultaneous biaxial stretching method. Good.

  In the case of the simultaneous biaxial stretching method, for example, any stretching method such as inflation simultaneous biaxial stretching method or stenter simultaneous biaxial stretching method may be adopted, but from the viewpoint of film formation stability and thickness uniformity, An axial stretching method is preferred.

  When using a float type stenter in the stretching process, the variation in the linear velocity of the hot air is not particularly limited and is appropriately determined according to the type of film polymer used, but the amount of heat received by the film varies in the width direction. It is desirable to control the variation in the linear velocity of the hot air blown in the TD direction to within ± 1% so that there is no air flow. If it exceeds ± 1%, there is a possibility that the relationship of (Gh−Gl) /0.5 <tan (0.3 °) is not satisfied. In order to achieve within ± 1%, it can be adjusted in advance, for example, by changing the width of the slit nozzle that ejects hot air.

  The stretching temperature in the stenter is desirably Tg-80 ° C. or higher and lower than Tg + 130 ° C. When stretching is performed at a temperature lower than Tg−80 ° C. or Tg + 130 ° C. or higher, the film may be stretched or broken with a non-uniform thickness, or may be loosened.

  Although a draw ratio is not specifically limited, Although it determines suitably by the kind of film polymer to be used, Preferably it is 1.0-8.0 times in length and 1.3-8.0 times in width. Further, after biaxial stretching, it may be re-stretched vertically or horizontally, or vertically and horizontally.

(Winding process)
It is desirable to perform the oscillation either in the jumbo roll winding in the film forming process or in the winding in the slit process so that the air is not stacked on the same part during winding. The oscillation width is not particularly limited, but can be 60 to 300 mm.

(Slit process)
In the step of slitting the plastic film of the present invention into the product width, the humidity control value of the slit environment is appropriately determined depending on the type of the film polymer, but it is preferable to control the relative humidity to be less than 30%. By suppressing the humidity to less than 30%, it is possible to suppress the film from absorbing moisture from the slit cut edge, and in particular, to prevent the end from becoming helicopter height.

  The winding tension is desirably 20 N / m or more and less than 200 N / m. If it is less than 20 N / m, wrinkles may occur at the time of winding. If it exceeds 200 N / m, the (Gh-Gl) of the original fabric shape may increase or the original fabric may be broken in the slit.

  The winding surface pressure is desirably 50 N / m or more and less than 700 N / m. If it is less than 50 N / m, there is a possibility that the amount of air entrainment increases and winding deviation occurs. When it is 700 N / m or more, the air entrapment rate decreases, the films do not slide each other, wrinkles may occur during winding, and defects due to charging may occur due to friction.

  Rubber, carbon, stainless steel, or the like can be used as the material of the contact roll that applies the surface pressure. Although not particularly limited, it is desirable to use a contact roll having a Shore hardness of 50 degrees or more. When the Shore hardness is less than 50 degrees, the surface pressure cannot be sufficiently applied, and the amount of air entrainment may increase, causing winding slippage.

  The slit speed is desirably 20 m / min or more and less than 500 m / min. If it is less than 20 m / min, the production efficiency is poor, and if it exceeds 500 m / min, defects due to charging may occur, or the amount of air entrainment may increase and cause winding displacement.

  Next, the measurement method used in the present invention is shown.

(Roll average diameter D)
The roll average diameter D was determined by the following method.

  The outer peripheral length of the film roll was measured using a tape measure having a dimensional accuracy of 100 μm at 1 point from the both ends in the roll width direction and the center position, and the average value was defined as De (mm).

  The roll average diameter D was defined by the following formula.

Roll average diameter D = De / π
(Original fabric shape value)
<Measurement>
The displacement in the width direction of the roll diameter of the film roll (original fabric shape) was measured using an original fabric shape measuring instrument (manufactured by Kitano Planning Co., Ltd.). A linear gauge (LGB-110), which is a detector attached to the measuring instrument, was brought into contact with the surface of the product roll, and was run on a dedicated rail at a speed of 12.5 mm / sec. The displacement of the roll diameter detected by the detector was output every 0.5 mm in the roll width direction via the D / A conversion unit (LG-DA1) and the linear gauge counter (LG-S1). The output data G1, G2, G3,... GX (mm) correspond to the roll diameter (mm) at the measurement position. In consideration of the effect of the height of the helicopter, the measurement width was measured by excluding 10 mm at each end. In the case of a film roll having a width of 1014 mm, when the measurement is performed by excluding the end portion, the number of measurement values of the obtained raw fabric shape value is 1989 points (as a measurement value pair, 1988 pairs).

The measurement was performed 3 times every 120 degrees with respect to the roll diameter.
<Fabric shape feedback>
The difference between the measured roll original fabric shape data and the target original fabric shape was obtained, and the value was divided by the number of laminated films, thereby calculating the target thickness value per film of the full width of the jumbo roll. In addition, it was assumed that the original fabric shape values at both ends of the roll excluded from measurement coincided with the original fabric shape target values. By inputting the thickness target value to the automatic die program, the bolt ON rate of the automatic die was adjusted, and the lip gap of the die corresponding to the concave or convex thickness target value was adjusted.
<Judgment>
With respect to all adjacent measurement value pairs of the raw roll shape value of the obtained roll, the larger value of the roll diameter is Gh (mm), the smaller value is Gl (mm),
It is confirmed whether (Gh−Gl) /0.5 is less than tan (0.3 °), and (Gh−Gl) /0.5 <tan (0.3 °) for all measured value pairs. In the case of ○, when there is a set of positions where (Gh−Gl) /0.5≧tan (0.3 °), it was marked as “x”.

(Surface roughness)
Using a non-contact optical roughness measuring instrument (apparatus: New View 7300 manufactured by Zygo), 10 fields of view were measured at a measurement area of 139 μm × 104 μm using a 50 × objective lens at random locations. The sample set is measured by setting the sample on the stage so that the measurement Y axis is in the MD direction of the sample film. An arithmetic average roughness (Ra) is obtained for each field of view using a bandpass filter with a wavelength of 1.65 to 50 μm by the surface analysis software MetroPro built in the roughness meter, and the average value is calculated for the surface roughness (Ra). It was.

(Air biting rate)
The air entrapment rate was calculated by the following formula using roll average diameter D (mm), film product length Lmm, outer diameter Dc (mm) of the winding core, and film average thickness t (μm) shown in the next section.

Air entrapment rate (%) = 100 × (D − ((L × t / 1,000 / π + Dc × Dc / 4) ^0.5 ) × 2) / D
(Measurement method of film average thickness t)
Film samples are taken across the entire width of the product. Ten sheets of these are stacked and measured using a micrometer manufactured by Mitutoyo Corporation, and divided by 10 to obtain the thickness per sheet. Sampling locations are uniformly 10 in the width direction, and the average value is taken as the average film thickness t (μm).

(Film thickness unevenness)
From the measured values of the film thickness at the 10 locations, ((maximum value−minimum value) / average value) × 100 (%) was defined as thickness unevenness.

(Measurement method of film dimensional change rate)
Two lines are drawn on the film surface so that the width is 10 mm and the measurement length is about 100 mm, and the distance between the two lines is accurately measured at 23 ° C., and this is defined as α0. This film sample was left in an oven at 100 ° C. for 10 minutes under a load of 1.5 g, and then the distance between the two lines was measured again at 23 ° C., and this was designated as α1. Obtain the dimensional change rate.

  Dimensional change rate (%) = {(α0−α1) / α0] × 100.

  Next, the evaluation method used in the present invention is shown.

(Applicability)
[Preparation of magnetic tape for evaluation]
A film roll stored for one month after film formation is unwound at a tension of 200 (N / m), and a magnetic coating and a non-magnetic coating having the following composition are applied on one surface (A surface) of the support by an extrusion coater (upper layer) Was applied with a magnetic paint to a coating thickness of 0.2 μm, and the lower layer was applied with a nonmagnetic paint to a coating thickness of 0.9 μm.), Magnetically oriented, and dried at 100 ° C. Next, a back coat having the following composition was applied to the opposite surface (B surface), and then a small test calender (steel / nylon roll, 5 steps) at a temperature of 85 ° C. and a linear pressure of 2.0 × 10 ⁵ N / After calendering with m, it was wound up as a tape original. The original tape was slit into a 1/2 inch (12.65 mm) width.

(Composition of magnetic paint)
Ferromagnetic metal powder: 100 parts by mass [Fe: Co: Ni: Al: Y: Ca = 70: 24: 1: 2: 2: 1 (mass ratio)]
[Long axis length: 0.09 μm, axial ratio: 6, holding force: 153 kA / m (1,922 Oe), saturation magnetic ratio: 146 Am ² / kg (146 emu / g), BET specific surface area: 53 m ² / g, X Linear particle size: 15 nm]
Modified vinyl chloride copolymer (binder): 10 parts by mass (average polymerization degree: 280, epoxy group content: 3.1% by mass, sulfonic acid group content: 8 × 10 ⁻⁵ equivalent / g)
-Modified polyurethane (binder): 10 parts by mass (number average molecular weight: 25,000, sulfonic acid group content: 1.2 × 10 ⁻⁴ equivalent / g, glass transition point: 45 ° C.)
Polyisocyanate (curing agent): 5 parts by mass (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name: Coronate L)
2-ethylhexyl oleate (lubricant): 1.5 parts by mass Palmitic acid (lubricant): 1 part by mass Carbon black (antistatic agent): 1 part by mass (average primary particle size: 0.018 μm)
Alumina (abrasive): 10 parts by mass (α alumina, average particle size: 0.18 μm)
-Methyl ethyl ketone: 75 parts by mass-Cyclohexanone: 75 parts by mass-Toluene: 75 parts by mass (composition of nonmagnetic paint)
Modified polyurethane: 10 parts by mass (number average molecular weight: 25,000, sulfonic acid group content: 1.2 × 10 ⁻⁴ equivalent / g, glass transition point: 45 ° C.)
-Modified vinyl chloride copolymer: 10 parts by mass (average polymerization degree: 280, epoxy group content: 3.1% by mass, sulfonic acid group content: 8 × 10 ⁻⁵ equivalent / g)
-Methyl ethyl ketone: 75 parts by mass-Cyclohexanone: 75 parts by mass-Toluene: 75 parts by mass-Polyisocyanate: 5 parts by mass (trade name: Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.)
・ 2-ethylhexyl oleate (lubricant): 1.5 parts by mass Palmitic acid (lubricant): 1 part by mass (composition of back coat)
Carbon black: 95 parts by mass (antistatic agent, average primary particle size 0.018 μm)
Carbon black: 10 parts by mass (antistatic agent, average primary particle size 0.3 μm)
・ Alumina (α alumina, average particle size: 0.18 μm)
Modified polyurethane: 20 parts by mass (number average molecular weight: 25,000, sulfonic acid group content: 1.2 × 10 ⁻⁴ equivalent / g, glass transition point: 45 ° C.)
Modified vinyl chloride copolymer (average polymerization degree: 280, epoxy group content: 3.1% by mass, sulfonic acid group content: 8 × 10 ⁻⁵ equivalent / g)
Cyclohexanone: 200 parts by mass Methyl ethyl ketone: 300 parts by mass Toluene: 100 parts by mass [Evaluation of coatability]
About the tape produced above, the coating property of the magnetic layer of the tape was evaluated by visually confirming the coating unevenness for 1000 m. ○: No coating unevenness Δ: Almost no coating unevenness ×: Coating unevenness [Evaluation of curvature]
In accordance with JISX6175 (2006), a tape length of 1.0 m was unwound and the deviation from a string with a tape length of 1.0 m was measured on a smooth surface.

○: Less than 3.8 mm ×: 3.8 mm or more

  Specific examples of the present invention are shown below, but the present invention is not limited thereto.

Example 1
(1) Preparation of PET pellets Polyethylene terephthalate pellets (50 mass%) substantially free of particles and "Ultem" (registered trademark) 1010 (hereinafter abbreviated as PEI) (50 mass%) manufactured by SABIC Innovative Plastics Co., Ltd. are 290 ° C. The pellet I containing 50% by mass of PEI was prepared by feeding to a bent biaxial kneading extruder of the same direction rotation type heated to 1.

  Supply polyethylene terephthalate containing spherical silica particles having an average particle size of 0.06 μm, pellet I, and polyethylene terephthalate substantially free of particles to a bi-axial kneading extruder of the same direction rotation type heated to 280 ° C. Thus, a thermoplastic resin A having a spherical silica particle content of 0.032% by mass and a PEI content of 3% by mass was obtained.

  Further, polyethylene terephthalate containing spherical silica particles having an average particle diameter of 0.06 μm, polyethylene terephthalate containing divinylbenzene / styrene copolymer crosslinked particles having an average particle diameter of 0.3 μm, and divinylbenzene having an average particle diameter of 0.45 μm. Polyethylene terephthalate containing crosslinked styrene / styrene copolymer particles, pellets I, and polyethylene terephthalate pellets substantially free of particles were fed to a bent biaxial kneading extruder of the same direction rotation type heated to 300 ° C. The particle content of 0.06 μm is 0.17% by mass, the particle content of 0.3 μm is 0.19% by mass, the particle content of 0.45 μm is 0.011% by mass, and the amount of PEI is 3% by mass. The resulting thermoplastic resin B was obtained.

  These thermoplastic resins were each dried under reduced pressure at 160 ° C. for 8 hours, then supplied to separate extruders, melt-extruded at 275 ° C. and filtered with high precision, and then merged and laminated with a rectangular two-layer merge block. Two layers were laminated such that the thickness ratio of the resin A was 85% and the resin B was 15% in the vertical direction. Thereafter, the film was wound around a casting drum having a surface temperature of 25 ° C. by using an electrostatic application casting method on a cooling roll through a slit die kept at 295 ° C., and solidified by cooling to obtain an unstretched laminated film.

  This laminated unstretched film was led to a simultaneous biaxial stretching tenter, and stretched at a temperature of 90 ° C. at the same time in the length direction and the width direction by 3.50 times. Subsequently, the film was re-stretched at 1.20 times and 1.40 times at the same time in the length direction and the width direction at a temperature of 190 ° C. Then, after a heat treatment at a temperature of 215 ° C. for 3.0 seconds, a relaxation treatment of 2.00% in the width direction was performed at a temperature of 160 ° C. Then, it cooled uniformly at 25 degreeC, the film edge was removed, and it wound up on the core with the oscillation width of 200 mm, and obtained the jumbo roll of the 4.3 micrometer-thick biaxially-oriented polyester film.

  Next, it is slit with a slitter at a winding speed of 200 m / min, a winding surface pressure of 200 N / m, a winding tension of 100 N / m and a small width (1,014 mm), with a runout of 0.02 mm, a cylindricity of 0.05 mm, On a cylindrical core of fiber reinforced plastic (FWP) core A (FWP10 manufactured by Tenryu Kogyo Co., Ltd.) having an axial elastic modulus of 14.5 GPa, a bending strength of 210 MPa, a surface hardness of 85, an outer diameter of 167 mm, and an inner diameter of 152.5 mm. Rolled up into a roll. The original film shape of this roll was measured, the target film thickness was calculated from the difference between the output value and the target original film shape, and fed back to the automatic die program. By this feedback, the bolt ON rate of the automatic die was adjusted, and the lip gap of the die corresponding to the convex or concave of the original fabric profile was adjusted. After that, the operation until the obtained jumbo roll is slit again under the same conditions and fed back to the automatic die is determined by the following equation: (Gh−G1) /0.5 <tan (0 .3 °). Thereafter, a film roll having a width of 1,014 mm, a winding length of 5,000 m, and an average diameter of 236 mm was obtained from the slit.

  After the roll was stored in a warehouse for one month, the roll was unwound and evaluated for applicability and bendability. As a result, all measured value pairs of the original fabric shape were conditional: (Gh-Gl) / 0. 5 <tan (0.3 degree) was satisfy | filled and the tape excellent in applicability | paintability and tape curvature was obtained.

(Example 2)
In the same manner as the thermoplastic resin A of Example 1, a thermoplastic resin C was obtained by adjusting the content of spherical silica particles to 0.20 mass% and the PEI content to 1.85 mass%.
Further, polyethylene terephthalate containing divinylbenzene / styrene copolymer crosslinked particles having an average particle size of 0.3 μm, polyethylene terephthalate containing divinylbenzene / styrene copolymer crosslinked particles having an average particle size of 0.8 μm, pellet I, and Polyethylene terephthalate pellets substantially free of particles are fed to a co-rotating bent type twin-screw kneading extruder heated to 280 ° C., and the particle content of 0.3 μm is 0.26% by mass, 0 A thermoplastic resin D having a particle content of .8 μm of 0.01% by mass and a PEI amount of 10% by mass was obtained. These were extruded in the same manner as in Example 1 to form a film, and a biaxially oriented polyester film jumbo roll having a thickness of 5.0 μm was obtained.

  Next, the raw film shape was measured until all measured value pairs of the original film shape of the film roll slit as in Example 1 satisfied the conditional expression: (Gh−G1) /0.5 <tan (0.3 °). Was fed back to the base, and then a film roll having a width of 1,014 mm, a winding length of 13,000 m, and an average diameter of 335 mm was obtained from the obtained jumbo roll. The winding conditions were a speed of 220 m / min, a winding surface pressure of 180 N / m, and a winding tension of 100 N / m. In this roll, all the measured value pairs of the original fabric shape satisfy the conditional expression: (Gh−Gl) /0.5 <tan (0.3 °), and the coating property and the bending property are good.

(Example 3)
In N-methyl-2-pyrrolidone (hereinafter referred to as NMP), 2-chloroparaphenylenediamine (hereinafter referred to as CPA) corresponding to 85 mol% and diphenyl ether (hereinafter referred to as DPE) corresponding to 15 mol% are dissolved, and this solution is filtered. After filtering through a filter made of 1.0 μm polypropylene, it was transferred to a polymerization tank, and chloroterephthalic acid chloride (hereinafter referred to as 98.5 mol%) passed through a filter made of polypropylene having a filtration accuracy of 1.0 μm. CTPC) is added, and before polymerization, silica particles having an average particle size of 80 nm are 0.02% by mass with respect to the aromatic diamine component, and organic particles having an average particle size of 100 nm are 6.0% by mass with respect to the aromatic diamine component. %, And stirred for 2 hours at 30 ° C. or lower to obtain a polymerized polymer.
Next, 98.5 mol% lithium carbonate was added to the hydrogen chloride in the polymerized polymer and neutralized for 4 hours, and 10 mol% triethanolamine was added to the hydrogen chloride in the polymerized polymer. Then, stirring was performed for 1 hour to obtain an aromatic polyamide solution A having a polymer concentration of 10.8% by mass.

  Further, CPA corresponding to 85 mol% and DPE corresponding to 15 mol% are dissolved in NMP, and this solution is filtered through a filter made of polypropylene having a filtration accuracy of 1.0 μm, and then transferred to a polymerization tank. To this was added CTPC corresponding to 98.5 mol% passed through a filter made of polypropylene having a filtration accuracy of 1.0 μm, and the mixture was stirred at 30 ° C. or lower for 2 hours to obtain a polymerized polymer.

  Next, 98.5 mol% of lithium carbonate was added to the hydrogen chloride in the polymerized polymer and neutralized for 4 hours to obtain silica having an average primary particle size of 16 nm (“AEROSIL” manufactured by Nippon Aerosil Co., Ltd.). R972 type) was added to 1.6% by mass with respect to the polymer and stirred for 1 hour, and then 10 mol% of triethanolamine was added to hydrogen chloride in the polymerized polymer and stirred for 1 hour. The aromatic polyamide solution B having a polymer concentration of 10.8% by mass was obtained.

  Next, the aromatic polyamide solution A is passed through a metal fiber filter made of stainless steel with a filtration accuracy of 1.2 μm, and the aromatic polyamide solution B is passed through a metal fiber filter made of stainless steel with a filtration accuracy of 5.0 μm, and then inside the base Laminated. At this time, the lamination ratio (thickness ratio) of the aromatic polyamide solutions A and B was set to 50%. Next, the laminated polymer solution is cast on a stainless steel belt having a mirror-like surface, and heated for 2 minutes with hot air at 180 ° C. on the belt on the downstream side in the running direction from the base to evaporate the solvent, thereby providing self-retaining properties. The obtained film body was continuously peeled from the belt.

  Next, the film body was introduced into the tank of the solvent extraction processing apparatus, and the remaining solvent and the inorganic salt produced by neutralization were extracted with water by 1.15 times in the MD direction.

  Thereafter, the obtained film body was held by a clip of a horizontal stretching machine, dried and heat-treated for moisture, dried at 245 ° C. for 1.5 minutes, and stretched 1.43 times in the TD direction. The film edge was removed by slow cooling at a rate of 20 ° C./second, and wound on the core with an oscillation of 60 mm to obtain an aromatic polyamide film jumbo roll having an average thickness of 3.6 μm.

  Then, as in Example 1, the raw film shape was changed until all measured value pairs of the original film shape of the slit film roll satisfied the conditional expression: (Gh−G1) /0.5 <tan (0.3 °). A film roll having a width of 1,014 mm, a winding length of 12,000 m, and an average diameter of 300 mm was obtained from the resulting jumbo roll. The winding conditions were a speed of 30 m / min, a winding surface pressure of 250 N / m, and a winding tension of 50 N / m. In this roll, all measured value pairs of the original fabric shape satisfy the conditional expression: (Gh-Gl) /0.5 <tan (0.3 °), and the coating property and the bending property were good.

Example 4
In Example 3, the heat treatment temperature of the transverse stretching machine was 250 ° C., the TD stretching ratio was 1.46 times, and an aromatic polyamide film jumbo roll having an average thickness of 1.3 μm was obtained.

  Then, as in Example 1, the raw film shape was changed until all measured value pairs of the original film shape of the slit film roll satisfied the conditional expression: (Gh−G1) /0.5 <tan (0.3 °). A film roll having a width of 1,014 mm, a winding length of 7,000 m, and an average diameter of 200 mm was obtained from the resulting jumbo roll. The winding conditions were a speed of 40 m / min, a winding surface pressure of 300 N / m, and a winding tension of 100 N / m. In this roll, all measured value pairs of the original fabric shape satisfy the conditional expression: (Gh-Gl) /0.5 <tan (0.3 °), and the coating property and the bending property were good.

(Example 5)
In Example 3, the heat treatment temperature of the transverse stretcher was 241 ° C., the TD stretch ratio was 1.44 times, and an aromatic polyamide film jumbo roll having an average thickness of 20 μm was obtained.

  Then, as in Example 1, the raw film shape was changed until all measured value pairs of the original film shape of the slit film roll satisfied the conditional expression: (Gh−G1) /0.5 <tan (0.3 °). After feeding back to the die, a film roll having a width of 1,014 mm, a winding length of 7,000 m, and an average diameter of 492 mm was obtained from the obtained jumbo roll. The winding conditions were a speed of 30 m / min, a winding surface pressure of 100 N / m, and a winding tension of 70 N / m. In this roll, all measured value pairs of the original fabric shape satisfy the conditional expression: (Gh-Gl) /0.5 <tan (0.3 °), and the coating property and the bending property were good.

(Comparative Example 1)
Polyethylene terephthalate containing calcium carbonate particles having an average particle diameter of 1.05 μm and polyethylene terephthalate containing substantially no particles are fed to a co-rotating bent type twin-screw kneading extruder heated to 280 ° C. A thermoplastic resin E having a calcium particle content of 1.0% by mass was obtained.

  Also, a bent biaxial kneading of the same direction rotating type pellets of polyethylene terephthalate containing divinylbenzene / styrene copolymer crosslinked particles having an average particle size of 0.3 μm and polyethylene terephthalate containing substantially no particles heated to 300 ° C. It was supplied to an extruder to obtain a thermoplastic resin F having a particle content of 0.3 μm of 2.0% by mass.

  Extruded in the same manner as in Example 1 in a two-layer laminate with a thickness ratio of thermoplastic resin E 90% and thermoplastic resin F 10%, and formed into a film with an MD stretch ratio of 3.45 times, a TD stretch ratio of 4.51 times, and an oscillation width of 120 mm. As a result, a jumbo roll of a biaxially oriented polyester film having an average thickness of 5 μm was obtained.

  Subsequently, the original fabric shape was slit without feeding back to the die, and a film roll having a width of 1014 mm, a winding length of 15,000 m, and an average diameter of 355 mm was obtained. The winding conditions were a speed of 250 m / min, a winding surface pressure of 300 N / m, and a winding tension of 90 N / m. There is a measurement value pair that does not satisfy the conditional expression: (Gh−Gl) /0.5 <tan (0.3 °) in the raw fabric shape of this roll. Was confirmed. In addition, the curvature of the corresponding part also exceeded the deviation of 3.8 mm.

(Comparative Example 2)
In Example 3, the layer thickness ratio of the A layer and the B layer was 25% and 75%, the heat treatment temperature of the transverse stretching machine was 280 ° C., the MD stretch ratio was 1.05, and the TD stretch ratio was 1.08. The film was formed to obtain an aromatic polyamide film jumbo roll having an average thickness of 12 μm.

  Subsequently, the original fabric shape was slit without feeding back to the die, and a film roll having a width of 1014 mm, a winding length of 2,000 m, and an average diameter of 248 mm was obtained. The winding conditions were a speed of 20 m / min, a winding surface pressure of 200 N / m, and a winding tension of 60 N / m. There is a measurement value pair that does not satisfy the conditional expression: (Gh−Gl) /0.5 <tan (0.3 °) in the raw fabric shape of this roll. Was confirmed. In addition, the curvature of the corresponding part also exceeded the deviation of 3.8 mm.

Claims (6)

A plastic film roll for a magnetic recording material in which a film is wound on a cylindrical core, the roll average diameter D being 200 mm or more and 500 mm or less, and the original fabric shape value G1 measured for the roll every 0.5 mm in the width direction , G2, G3,..., GX (mm), when the value of the larger roll diameter in all adjacent measurement value pairs is Gh (mm) and the value of the smaller roll is Gl (mm),
(Gh−Gl) /0.5 <tan (0.3 °)
The plastic film roll for magnetic recording materials which has the original fabric shape value satisfy | filling the relationship which becomes. The plastic film roll for magnetic recording materials according to claim 1, wherein the surface roughness Ra of the surface on which the magnetic layer of the film is formed is 0.5 nm or more and 20 nm or less. The plastic film roll for magnetic recording materials according to claim 1 or 2, wherein the air biting rate is 0.5% or more and 25% or less. The plastic film roll for magnetic recording materials according to claim 1, wherein the film has a thickness of 1 μm or more and 20 μm or less. The plastic film roll for magnetic recording materials according to any one of claims 1 to 4, wherein the thickness unevenness of the film is 9% or less of the average film thickness t. The plastic film roll for magnetic recording materials according to any one of claims 1 to 5, wherein a rate of dimensional change after 100 ° C treatment of the film is 0% or more and 2% or less.