JP2000211082A - Easy slip composite polyester film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite polyester film excellent in surface flatness, easy slip properties at a time of the formation/processing of a film, blocking resistance and shaving resistance and useful for various uses, especially, for a base film of a high density magnetic recording medium. SOLUTION: In an easy slip composite polyester film wherein a continuous film layer having a fine reticulated uneven structure is provided on at least the single surface of a polyester film, the film layer contains inert fine particles with a mean particle size of 10-200 nm and the Ra (square average roughness) by AFM of the outer surface of the film layer is 3-20 nm and the height of projections by fine particles present in the recessed parts of the film layer is 0.3-3 times the height of the projected parts of the film layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slippery composite polyester film, and more particularly, to a flatness, excellent slipperiness during film formation and processing, excellent blocking resistance and abrasion resistance, a magnetic recording medium, and various photographs. Materials, packaging materials, electrical insulation materials,
The present invention relates to a slippery composite polyester film suitable as a base film used for general industrial materials and the like, particularly a base film for a ferromagnetic metal thin film type magnetic recording medium.

[0002]

2. Description of the Related Art A biaxially stretched polyester film represented by a polyethylene terephthalate film has excellent mechanical properties, heat resistance, chemical resistance, etc., and is therefore used for audio tapes, video tapes, computer tapes, floppy disks, video floppy disks. The demand for such materials as photographic film, wrapping film, metallizing film for capacitors, electrically insulating film, OHP film and the like has been particularly remarkable recently.

However, in order to smoothly produce a film and apply the film to the above-mentioned applications, it is inevitable to improve the slipperiness of the film.

For example, in the case of a film having a particularly flat surface, the slipperiness of the film is insufficient, which seriously hinders operations such as winding, rewinding, coating, slitting, and the like. Causes trouble such as dust absorption. For example, when various molded products produced by subjecting an unstretched or uniaxially stretched film of polyethylene terephthalate to pressure molding or vacuum molding are superimposed on each other, if the surface lubricity is insufficient, the molded products are mutually bonded. It cannot be removed smoothly, so that the workability in the working process is significantly reduced.

Conventionally, as a means for improving the slipperiness of a polyester film, for example, a film is formed by using a polyester to which fine particles of various fillers such as silicon oxide, kaolin, talc, calcium carbonate or alumina are added.
Then, when the film thickness is reduced in the biaxial stretching step, it has been put to practical use to utilize the phenomenon that the filler projects as fine projections on the film surface. Similarly, as a technique for improving the slipperiness utilizing minute projections, a method of converting a catalyst used in the polymerization of polyester into particles insoluble in a polymer is also known.

Although these methods have been successful in improving the slipperiness of the film, the presence of fine particles in the film composition naturally lowers the transparency of the film or reduces the fine particles. Coarse projections or F / S are formed on the film surface by the large-diameter particles mixed in a small amount in the agglomerates and fine particles, and the D / O of the video tape is reduced.
Or leaving voids in the film composition to be improved. In particular, diazo film, metallizing film, photographic film, or polyester film as a material for magnetic tapes and floppy disks that require flattening of the surface of the base film by densification, decrease in transparency or generation of voids and coarse protrusions Is a serious obstacle.

Further, as another means for improving the slipperiness,
There is known a method in which a coating film containing fine particles is provided on at least one surface of a film, and fine projections are formed on the film. This method has a problem that even though lubricity can be ensured, the adhesion of the polyester film is not sufficient and the abrasion resistance is poor.

Particularly, as a base film of an extremely high-density magnetic recording medium, in particular, a magnetic recording medium in which a magnetic layer is formed of a ferromagnetic metal thin film, ultra-flatness for providing a high output and easy slipping for winding the film. Contrary to the above, there is a need for a method of providing a lubricating film on the side of the tape on which the back coat layer is to be provided. However, although the conventional film can ensure lubricity, there is a problem of a so-called heat loss phenomenon in which a film is melted by heat of metal particles when a metal thin film is provided by vapor deposition.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to solve such problems and to provide excellent flatness, excellent slipperiness during film formation and processing, anti-blocking properties and abrasion resistance, magnetic recording media, and various types of photographs. It is an object of the present invention to provide a slippery composite polyester film suitable as a base film used for materials, packaging materials, electric insulating materials, general industrial materials, and the like, particularly as a base film for a ferromagnetic metal thin film magnetic recording medium.

[0010]

SUMMARY OF THE INVENTION The object of the present invention is to provide, according to the present invention, at least one side of a polyester film,
A composite polyester film provided with a continuous coating layer having a fine network uneven structure, wherein the coating layer has an average particle size of 10 to 10.
Ra (root mean square roughness) by AFM (atomic force microscope) on the outer surface of the coating layer having inert fine particles of 200 nm
Is 3 to 20 nm, and the height of projections of the fine particles present in the concave portions of the coating layer is 0.3 to 3 times the height of the convex portions of the coating layer. This is achieved by a composite polyester film.

The present invention will be described in detail below. As the polyester constituting the polyester film of the present invention,
Polyethylene terephthalate, polyethylene isophthalate, polytetramethylene terephthalate, poly-1,
Preferred examples include 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 a copolyester, as a copolymerization component of polyethylene terephthalate and polyethylene-2,6-naphthalenedicarboxylate, for example, diethylene glycol, propylene glycol, neopentyl glycol, polyoxyethylene glycol, p-xylene glycol, 1,4-cyclohexane Diol components such as dimethanol, adipic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid (for polyethylene-2,6-naphthalenedicarboxylate), 2,6-naphthalenedicarboxylic acid (for polyethylene terephthalate) ) Other dicarboxylic acid components such as 5-sodium sulfoisophthalic acid,
and oxycarboxylic acid components such as p-oxyethoxybenzoic acid. The amount of the copolymer component is preferably 20 mol% or less, more preferably 10 mol% or less, based on all the acid components.

Further, a trifunctional or higher polyfunctional compound such as trimellitic acid or pyromellitic acid can be copolymerized. In this case, it is preferable to copolymerize the polymer in a substantially linear amount, for example, 2 mol% or less.

The thickness of the polyester film in the present invention is preferably 1 to 20 μm, more preferably 2 to 10 μm.

The polyester film in the present invention comprises:
It may or may not contain inert particles.
When it is contained, organic particles or inorganic particles may be used.

In the inert particles, organic particles include polystyrene, polystyrene-divinylbenzene, polymethyl methacrylate, methyl methacrylate copolymer, cross-linked methyl methacrylate, polytetrafluoroethylene, polyvinylidene fluoride,
Polyacrylonitrile, particles made of a polymer such as a benzoguanamine resin, and core-shell structured particles made of a graft copolymer containing these polymers as components are preferable.Inorganic particles include silica, alumina,
Particles composed of inorganic compounds such as titanium dioxide, feldspar, kaolin, talc, graphite, calcium carbonate, molybdenum disulfide, carbon black and barium sulfate are preferred.

These particles are usually used during the production of polyester,
For example, it is added to the reaction system at any time during the transesterification reaction or polycondensation reaction in the case of the transesterification method, or at any time in the case of the direct polymerization method, preferably as a slurry in glycol. The average particle size of the inert particles is 0.005 to 2 μm, and further 0.01 to 1.8 μm.
And the amount of addition is preferably 0.001 to 2% by weight, more preferably 0.01 to 1.5% by weight.

The polyester film in the present invention is A
Ra (root mean square roughness) by FM is preferably 0.1 to 5 nm, more preferably 0.3 to 4 nm. The polyester film may be a single-layer film or a multi-layer film composed of two or more polyester films having different compositions.

The continuous film layer having a fine network uneven structure in the present invention is preferably composed of a layer containing a binder resin, inert fine particles and a surfactant.

The binder resin constituting the continuous film in the present invention includes an alkyd resin, a phenol resin,
Examples thereof include an epoxy resin, an amino resin, a polyurethane resin, a cellulose resin, a vinyl acetate resin, and a vinyl chloride-vinyl acetate copolymer. Water-soluble or water-dispersible polyester resins, acrylic resins, and acryl-polyester resins are preferred from the viewpoints of adhesion to the polyester film, protrusion retention, lubricity, and the like.
These resins may be a homopolymer or a copolymer, or may be a mixture.

Examples of the acid component constituting the water-soluble or water-dispersible polyester resin include terephthalic acid, isophthalic acid, phthalic acid, 1,4-cyclohexanedicarboxylic acid, 2,6-naphthalenedicarboxylic acid,
4'-diphenyldicarboxylic acid, adipic acid, sebacic acid, dodecanedicarboxylic acid, succinic acid, 5-sodium sulfoisophthalic acid, 2-potassium sulfoterephthalic acid, trimellitic acid, trimesic acid, trimellitic anhydride, phthalic anhydride, Examples thereof include polyvalent carboxylic acids such as p-hydroxybenzoic acid and monopotassium trimellitate.

Examples of the hydroxy compound component include ethylene glycol, propylene glycol,
3-propanediol, 1,4-butanediol, 1,
6-hexanediol, neopentyl glycol, 1,
4-cyclohexanedimethanol, p-xylylene glycol, ethylene oxide adduct of bisphenol A,
Examples thereof include polyhydroxy compounds such as diethylene glycol, triethylene glycol, polyethylene oxide glycol, polytetramethylene oxide glycol, dimethylolpropionic acid, glycerin, trimethylolpropane, sodium dimethylolethylsulfonate, and potassium dimethylolpropanoate. it can. A polyester resin can be prepared from these compounds by a conventional method. From the viewpoint of producing an aqueous paint, it is preferable to use an aqueous polyester resin containing a 5-sodium sulfoisophthalic acid component or a carboxylate group. Such a polyester resin can be a self-crosslinking type having a functional group in the molecule, or can be crosslinked using a curing agent such as a melamine resin or an epoxy resin.

Examples of the acrylic component used in the production of the water-soluble or water-dispersible acrylic resin include acrylates (alcohol residues include methyl, ethyl, n-propyl, isopropyl, and n-butyl). Group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group, phenyl group, benzyl group, phenylethyl group, etc.); methacrylic acid ester (the alcohol residue is the same as above); 2-hydroxyethyl Hydroxy-containing monomers such as acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate; acrylamide, methacrylamide, N-methylmethacrylamide, N-methylacrylamide, N-
Amide group-containing monomers such as methylol acrylamide, N-methylol methacrylamide, N, N-dimethylol acrylamide, N-methoxymethyl acrylamide, N-methoxymethyl methacrylamide, N-phenylacrylamide; N, N-diethylaminoethyl acrylate; Amino group-containing monomers such as N, N-diethylaminoethyl methacrylate and the like can be mentioned. These monomers include sulfonic acid groups such as styrene sulfonic acid, vinyl sulfonic acid and salts thereof (eg, sodium salt, potassium salt, ammonium salt and the like) or a salt thereof; crotonic acid, itaconic acid,
Monomers containing a carboxyl group or a salt thereof, such as acrylic acid, maleic acid, fumaric acid, and salts thereof (eg, sodium salt, potassium salt, ammonium salt, etc.); anhydrides such as maleic anhydride, itaconic anhydride, etc. Containing monomers; other vinyl isocyanate, allyl isocyanate, styrene, vinyl methyl ether, vinyl ethyl ether, vinyl tris alkoxysilane,
It can be used in combination with monomers such as alkyl maleic acid monoester, alkyl fumaric acid monoester, acrylonitrile, methacrylonitrile, alkyl itaconic acid monoester, vinylidene chloride, vinyl acetate, vinyl chloride, and allyl glycidyl ether. In this case, it is preferable that a component of a (meth) acrylic monomer such as an acrylic acid derivative and a methacrylic acid derivative is contained in an amount of 50 mol% or more, and it is particularly preferable that a component of methyl methacrylate is contained.

The water-soluble or water-dispersible acrylic resin can be self-crosslinked with a functional group in the molecule, or can be crosslinked with a crosslinking agent such as a melamine resin or an epoxy compound.

In the present invention, the water-soluble or water-dispersible acryl-polyester resin is used to include the acryl-modified polyester resin and the polyester-modified acryl resin, and the acryl resin component and the polyester resin component are bonded to each other. And includes, for example, a graft type and a block type. Acrylic-polyester resins, for example, add a radical initiator to both ends of the polyester resin to cause polymerization of the acrylic monomer, or add a radical initiator to the side chain of the polyester resin to polymerize the acrylic monomer. Alternatively, it can be produced by attaching a hydroxyl group to the side chain of the acrylic resin and reacting it with a polyester having an isocyanate group or a carboxyl group at a terminal to obtain a comb polymer.

The components constituting the acryl-polyester resin include the compounds exemplified as the components constituting the acrylic resin and the polyester resin.

The content of the water-soluble or water-dispersible resin in the continuous film of at least one resin selected from the group consisting of polyester resins, acrylic resins and acrylic-polyester resins is preferably 20 to 80% by weight. If it is less than 20% by weight, the adhesion to the film is reduced, while if it exceeds 80% by weight, other components (inert fine particles, surfactants, etc.) are insufficient, and the overall properties cannot be satisfied.

As shown in FIG. 1, the continuous film layer having a fine network uneven structure according to the present invention is a continuous film having a net-like surface shape and having inert fine particles also at the mesh portion. It is.

As a means for forming the surface of the continuous film layer into a fine network uneven structure, as a part of the binder resin, polyvinyl alcohol, gelatin, cellulose, a styrene copolymer containing a sulfonate group, or the like is used. A method using a poor resin is preferably applicable. The content of the poorly spreadable resin in the continuous film is preferably 5 to 50% by weight, more preferably 10 to 40% by weight. If the amount is less than 5% by weight, the continuous film does not have a sufficient fine network structure, so that slipperiness is insufficient. If it exceeds 50% by weight, the abrasion resistance of the continuous film itself is reduced.
It is not preferable.

Examples of the material of the inert fine particles contained in the continuous coating layer include polystyrene, polystyrene-divinylbenzene, polymethyl methacrylate, methyl methacrylate copolymer, cross-linked methyl methacrylate copolymer, polytetrafluoroethylene, and polyvinylidene. Organics such as fluoride, polyacrylonitrile, benzoguanamine resin, silica, alumina, titanium dioxide,
Any of inorganic substances such as kaolin, talc, graphite, calcium carbonate, feldspar, molybdenum disulfide, carbon black, barium sulfate and the like may be used. Alternatively, core-shell type particles having a multilayer structure in which the inside and outside are made of substances having different properties may be used.

The average particle size of the inert fine particles is preferably 10
To 200 nm, more preferably 20 to 100 nm, and the content of the fine particles in the continuous film layer is preferably 5 to 200 nm.
It is 40% by weight, more preferably 5 to 20% by weight.
Further, the fine particles preferably have a narrow particle size distribution, and more preferably have a substantially uniform particle size. This average particle size is 10
nm or less than 5% by weight,
The film is insufficient in slipperiness, so that winding property, transportability in a film forming process is insufficient, and blocking is easily caused. On the other hand, when the average particle size exceeds 200 nm or when the content exceeds 40% by weight, there is a problem that the film is easily shaved.

The surfactant contained in the continuous film layer in the present invention is not particularly limited, and examples thereof include a nonionic surfactant, an anionic surfactant, and a cationic surfactant. The content of this surfactant is preferably in the range of 5 to 40% by weight.

The coating layer in the present invention is a continuous coating, and its outer surface has an Ra (root mean square roughness) by AFM (atomic force microscope) of 3 to 20 nm, preferably 4 to 20 nm.
15 nm. When the Ra is less than 3 nm, the lubricity is insufficient, and the film winding property, the transport property in the film forming process are insufficient, and blocking is liable to occur. on the other hand,
When Ra exceeds 20 nm, the coating layer is easily scraped.

In the continuous film layer of the present invention, the height of the projections due to the inert fine particles present in the concave portions of the continuous film is 0.3 to 3 times, preferably 0.5 to 2 times the height of the convex portions of the continuous film layer. Needs to be If the height is less than 0.3 degrees, blocking tends to occur, while if it exceeds three times, it is easy to scrape.

The area ratio of the projections / concave portions of the continuous coating layer is 0.2 to 5, more preferably 0.3 to 3, especially 0.5 to 2.
It is desirable that If this ratio is less than 0.2, the coefficient of friction increases, and the lubricity becomes insufficient. On the other hand, when it exceeds 5, blocking tends to occur.

The frequency of protrusions due to the inert fine particles present in the recesses of the continuous film layer is 1 × 10 ⁴ to 1 × 10 ⁸ / m.
m ² is preferred. This frequency is 1 × 10 ⁴ pieces /
If it is less than ² mm, the slipperiness is insufficient, while 1 ×
If it exceeds 10 ⁸ pieces / mm ² , it becomes easy to scrape.

In the continuous film layer of the present invention, other components besides the binder resin, the inert fine particles and the surfactant may be added as long as they do not affect the present invention. For example, in order to further improve the blocking resistance, a method of adding a silicone wax or a siloxane copolymer is preferably used.

The thickness of the continuous coating layer in the present invention is 1 to 1
The thickness is preferably 00 nm, more preferably 3 to 30 nm.

The composite polyester film of the present invention can be produced according to a conventionally known method.

For example, when the polyester film is a single layer, the polyester is melted at a melting point of Tm ° C. to (Tm + 7
0) After extruding into a film at a temperature of 40 ° C.,
To obtain an unstretched film. Thereafter, the unstretched film is placed in a uniaxial direction (longitudinal or transverse direction) at a temperature of (Tg-10) to (Tg + 70) ° C. (where Tg: glass transition temperature of polyester) in a range of 2.5 to 8 in a conventional manner. The film is stretched at a magnification of 0.0 times, preferably 3.0 to 7.5 times, and then a coating solution for forming a film is applied to at least one surface of the film. 2.5 at the temperature of (Tg + 70) ° C.
The film is stretched at a magnification of up to 8.0 times, preferably at a magnification of 3.0 to 7.5 times. Further, if necessary, the film may be stretched again in the machine direction and / or the cross direction.

That is, the stretching may be performed in two, three, four or more stages. The total stretching ratio is usually 9 times or more, preferably 12 to 35 times, more preferably 15 to 32 times as the area stretching ratio. Subsequently, the biaxially oriented film is heat-set and crystallized at a temperature of (Tg + 70) to (Tm-10) ° C., for example, 180 to 250 ° C., thereby giving excellent dimensional stability. The heat setting time is 1
~ 60 seconds is preferred.

The composite polyester film of the present invention is used in various fields.
In particular, it is useful as a base film for a ferromagnetic metal thin film type magnetic recording medium.

The composite polyester film of the present invention is formed on the surface opposite to the surface on which the continuous film layer is formed by a method such as vacuum deposition, sputtering, or ion plating.
Form a ferromagnetic metal thin film layer composed of iron, cobalt, chromium, or an alloy or oxide containing these as a main component, and a protective layer such as diamond-like carbon (DLC) on the surface if necessary By providing a fluorine-containing carboxylic acid-based lubricating layer in sequence and further providing a known back coat layer on the surface of the continuous coating layer, it is particularly excellent in output in a short wavelength region and electromagnetic conversion characteristics such as S / N and C / N. , Drop-out, and error rate can be obtained as a vapor-deposited magnetic recording medium for high-density recording. This vapor-deposited electromagnetic recording medium can be used as a Hi8 for analog signal recording, a digital video cassette recorder (DVC) for digital signal recording, a 8 mm data, and a tape medium for DDSIV, and is extremely useful.

[0044]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. The measuring method used in the present invention is as follows.

(1) Average particle diameter of fine particles Measured using a light scattering method. That is, Nicom Instruments Inc.
instruments Inc. NICOMP M manufactured by
ODEL 270 SUBMICRON PARTIC
Expressed as the "equivalent spherical diameter" of the particle at the point of 50% by weight of the total particle as determined by LE SIZER.

(2) Surface roughness by AFM (atomic force microscope) Ra (22th root mean roughness) measured under the following conditions using an atomic force microscope Nano Scope III AFM J scanner manufactured by Digital Instruments Co., Ltd. ) Is measured under the following conditions, and an average value of n = 10 is used. Probe; single bond silicon sensor Scanning mode: tapping mode Scanning range: 10 μm × 10 μm Pixels: 256 × 256 data points Scanning speed: 2.0 Hz Measurement environment: room temperature, in air

(3) Area ratio of convex / concave portions of continuous film layer From the AFM image of 10 μm × 10 μm measured in (2),
The ratio of convex / concave portions is calculated by an image analysis method. n = 1
An average value of 0 is used.

(4) Height of protrusions due to inactive fine particles present in recesses of continuous film layer From the AFM image of 10 μm × 10 μm measured in (2),
The height of ten protrusions is randomly measured for one image, and the average value of a total of 100 protrusions of the ten AFM images is defined as the height (nm) of the protrusions.

(5) Height of convex portion of continuous film layer From the AFM image of 10 μm × 10 μm measured in (2),
The height of 10 continuous film projections was randomly measured for one image, the height of 100 continuous projections of 10 AFM images was measured in total, and the total of 100 AFM images of 10 images were measured. Is the height of the convex portion (nm).

(6) Frequency of protrusions due to inactive particles present in recesses in continuous film layer The number of protrusions present in the recesses is counted from the 10 μm × 10 μm AFM image measured in (2) and divided by the recess area. The frequency of the protrusions is calculated, and the average value of the ten AFM layers is defined as the frequency of protrusions (number / mm ² ).

(7) Coefficient of friction of film (μs) A fixed glass plate is placed under the two superposed films, and the film under the superposed film (the film in contact with the glass plate) is removed. Take off with a low-speed roll (about 10 cm / min), fix the detector at one end of the upper film (the end opposite to the take-up direction of the lower film) and detect the tensile force at the start between the films. . The thread used at that time weighs 1 kg and the lower area is 100
cm ² is used.

The coefficient of friction (μs) is obtained from the following equation. μs = tensile force at start (kg) / load 1 kg The evaluation is performed based on the following criteria. ；; less than 0.7 △; 0.7 or more and less than 0.80 ×; 0.80 or more

(8) Blocking resistance The processing surface of the two films and the surface to be processed are overlapped, and a pressure of 150 kg / cm ² is applied to the film at 60 ° C. and 80% R
The film is peeled after 65 hours in an atmosphere of H, and evaluated by its peeling force (g per 5 cm). The evaluation is performed based on the following criteria based on the peeling force. ：: 0 to less than 10 g / cm Δ: 10 g / cm or less to less than 15 g / cm ×: 15 g / cm or more to tear

(9) Abrasion resistance The film was sampled to a length of 25 to 30 cm and a width of 1/2 inch, and a razor blade was applied to the surface of the coating layer at an angle of 90 ° and a depth of 0.5 mm. , Load 500g /
The width in the depth direction of the shaved powder adhering to the leather when running at a speed of 6.7 cm / sec at a speed of 0.5 inch is determined by taking a microphotograph (× 160).

The following judgment is made based on the width of the shaving powder in the depth direction. The smaller the width of the shaving powder in the depth direction, the better the shaving properties. ：: less than 3 nm △: 3 nm to less than 5 nm ×: 5 nm or more

(10) Heat Loss Using a continuous winding vacuum evaporation apparatus as shown in FIG.
The composite polyester film is checked for heat loss.

The continuous winding type vacuum evaporation apparatus is configured for so-called oblique evaporation, and the inside thereof is in a vacuum state (for example, about 1 mm).
0 ⁻³ Pa), rotates in the counterclockwise direction (arrow Z direction) in the drawing and faces the cooling can 2 cooled to −20 ° C. in the vacuum chamber 1. An evaporation source 3 is provided.

Then, the composite polyester film is unwound in the direction of arrow D from the supply roll 4 rotating counterclockwise in FIG. The deposition material 6 heated and evaporated by the beam 5 is adhered, a metal magnetic thin film is deposited, and then wound around a winding roll 7. Guide rollers 8 and 9 are provided between the supply roll 4 and the cooling can 2 and between the cooling can 2 and the take-up roll 7, respectively. A predetermined tension is applied to the composite polyester film running from 2 to the take-up roll 7 so that the composite polyester film runs smoothly.

The vapor deposition source 3 is a container in which the above-mentioned metal magnetic material Co—Ni alloy is contained in a container 10, and the electron beam source 11 accelerates and irradiates the vapor deposition source (metal magnetic material) with an electron beam 5. Then, the metal magnetic material 6 is heated and evaporated, and is adhered (deposited) on the composite polyester film running along the peripheral surface of the cooling can 2 to form a metal magnetic thin film, thereby producing a magnetic recording medium. At this time, a deposition-preventing plate 12 is provided between the vapor deposition source 3 and the cooling can 2, and a shutter 13 is provided so as to be position-adjustable so that only vapor-deposited particles incident on the composite polyester film at a predetermined angle are passed. . Thus, a metal magnetic thin film is formed by the oblique deposition method.

When the continuous film layer side surface of the composite polyester film is oriented so as to be in contact with the cooling can, and a 180-nm-thick metal magnetic thin film is formed on the opposite film surface on which the continuous film is formed, the heat loss is evaluated according to the following criteria. carry out. (The width of the polyester film is 500 mm) ○: Heat loss △: Heat loss of 5 mm or more occurs at 3 pieces / 10 m length or more ×: Heat loss of 5 mm or more diameter occurs at 10 pieces / 10 m length or more

Example 1 Dimethyl 2,6-naphthalenedicarboxylate and ethylene glycol, manganese acetate as a transesterification catalyst, antimony trioxide as a polymerization catalyst, and phosphorous acid as a stabilizer were added in a conventional manner. To obtain polyethylene-2,6-naphthalate (PEN) containing substantially no inert particles.

The polyethylene-2,6-naphthalate was dried at 170 ° C. for 6 hours, fed to an extruder, melted at a melting temperature of 280 to 300 ° C., extruded into a sheet from a die, quenched, and cooled to a thickness. An 82 μm unstretched film was obtained.

The obtained unstretched film is preheated, further 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 coated on one side of the vertically-stretched film. The water-soluble coating liquid having the composition of the continuous coating layer shown in Table 1 and the water-soluble coating liquid of the other coating layer on the other surface were each 0.020 μm,
It was applied to a thickness of 0.009 μm (after stretching and drying), was subsequently supplied to a stenter, and was stretched 5.6 times in the horizontal direction at 150 ° C. The obtained biaxially stretched film was
The resultant was heat-set with hot air at 0 ° C. for 4 seconds to obtain a slippery composite polyester film having a thickness of 4.9 μm. Table 1 shows the characteristics of this film.

(Composition of the other surface film) Binder resin Acrylic-modified polyester SH551A manufactured by Takamatsu Oil & Fat Co., Ltd. 70 parts by weight Inert particles Acrylic particles (average particle size 40 nm) 10 parts by weight Surfactant Nippon Oil & Fats Co., Ltd. Nonion NS-240 20 parts by weight

Example 3, Comparative Examples 1, 5 A slippery composite polyester film was obtained in the same manner as in Example 1, except that the composition of the continuous coating layer was changed as shown in Table 1. Table 1 shows the characteristics of this film.

Examples 2 and 4 and Comparative Examples 2 to 4 Dimethyl terephthalate and ethylene glycol, manganese acetate as a transesterification catalyst, antimony trioxide as a polymerization catalyst, and phosphorous acid as a stabilizer were constantly added. Polymerization was carried out by the method to obtain polyethylene terephthalate (PET) containing substantially no inert particles.

This polyethylene terephthalate was converted to 170
After drying at 3 ° C. for 3 hours, the mixture was fed to an extruder and melted at 280 to 280 ° C.
It was melted at 300 ° C., extruded into a sheet from a die, and quenched 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 coated on one side of the vertically-stretched film. A water-soluble coating liquid having the composition of the coating layer shown in Table 1 and a water-soluble coating liquid having the same coating composition on the other side as in Example 1 were used on the other surface.
It was applied so as to have a thickness of 020 μm and 0.009 μm (after stretching and drying), was subsequently supplied to a stenter, and was 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 4 seconds to obtain a thickness of 6.0 μm.
m of a composite polyester film was obtained. Table 1 shows the characteristics of this film.

Comparative Examples 6 and 7 A composite polyester film was obtained in the same manner as in Example 2 except that the composition and the coating thickness of the continuous film layer were changed as shown in Table 1. Table 1 shows the characteristics of this film.

[0070]

[Table 1]

As is clear from Table 1, the slippery composite polyester film according to the present invention has a low coefficient of friction, no blocking between films, excellent abrasion resistance and no heat loss during vapor deposition. On the other hand, those which do not satisfy the requirements of the present invention cannot simultaneously satisfy these characteristics.

[0072]

According to the present invention, it is excellent in surface flatness, slipperiness in film formation and processing, blocking resistance and abrasion resistance, and is useful as a base film for high-density magnetic recording media in various applications. A complex polyester film can be provided.

[Brief description of the drawings]

FIG. 1 is a view schematically showing a fine network uneven structure of a continuous coating layer.

FIG. 2 is a schematic configuration diagram of a continuous winding type vapor deposition apparatus.

[Explanation of symbols]

 1: vacuum chamber 2: cooling can 3: evaporation source 4: film supply roll 6: evaporation material 7: film winding roll

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Toshifumi Osawa 3-37-19 Koyama, Sagamihara-shi, Kanagawa F-term in Sagamihara Research Center, Teijin Limited 4F100 AA20H AJ20A AK01A AK25A AK25H AK25J AK41B AK41J AK42B AL01A AR00C AR00D AS00A BA02 BA04 BA07 BA10C BA10D BA14 CA18A CA30 DD06 DD07 DD07A DD08 DD09 DD09A DE01A DE01H EC18A EJ91C GB41 HB21 JB05A JB09A JG06D JK12 JK15 JK16 JK16A JL00 JL00C JM01A YB00 CB01B01B

Claims (8)

[Claims] 1. A composite polyester film comprising a polyester film provided with a continuous film layer having a fine network uneven structure on at least one surface of the polyester film, wherein the film layer has an average particle size of 1.
It has inert fine particles of 0 to 200 nm, and the Ra (root mean square roughness) of the outer surface of the coating layer by AFM is 3 to 20 nm.
Wherein the height of the projections of the fine particles present in the concave portions of the coating layer is 0.3 to 3 times the height of the convex portions of the coating layer. 2. The slippery composite polyester film according to claim 1, wherein the continuous film layer has a convex / concave area ratio of 0.2 to 5. 3. The slippery composite polyester film according to claim 1, wherein the frequency of projections by inert fine particles present in the concave portions of the continuous film layer is 10 ⁴ to 10 ⁸ / mm ² . 4. The slippery polyester film according to claim 1, wherein the continuous film layer comprises a binder resin, inert fine particles, and a surfactant. 5. The binder resin forming the continuous film layer contains at least one resin selected from the group consisting of a water-soluble or water-dispersible polyester resin, an acrylic resin, and an acryl-polyester resin. 2. The slippery composite polyester film according to item 1. 6. The slippery composite polyester film according to claim 1, wherein the polyester film is a film composed of polyethylene terephthalate or polyethylene-2,6-naphthalenedicarboxylate. 7. The composite polyester film according to claim 1, wherein a continuous coating layer having a fine network uneven structure is provided on one side of the film, and a back coat layer is provided on the continuous coating layer, and magnetic recording is performed on the opposite side of the film. A magnetic recording medium provided with a layer. 8. The magnetic recording medium according to claim 7, wherein the magnetic recording layer is a ferromagnetic metal thin film layer.