JP2003136656A - Laminated polyester film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated polyester film excellent in blocking resistance, flatness, winding properties and processability and excellent in electromagnetic conversion characteristics when used in a metal vapor deposition type magnetic recording medium. SOLUTION: In the laminated film wherein a polyester layer A, a polyester layer B and a coating layer C are laminated in this order, the polyester layer B contains 0.001-1 wt.% of inert particles with a mean particle size of 50-1,000 nm and the polyester layer A contains no inert particles or contains inert particles A having a mean particle size smaller than the mean particle size of the inert particles contained in the polyester layer B and the coating layer C contains 1-40 wt. % of a cellulose compound wherein the viscosity of a 3 wt.% aqueous solution at 20 deg.C is 10-1,000 Pa/s.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated polyester film, and more particularly to a magnetic recording medium excellent in electromagnetic conversion characteristics and running durability, particularly a ferromagnetic metal thin film type magnetic recording medium for recording / reproducing digital signals, for example, The present invention relates to a laminated polyester film useful as a base film for digital video cassette tapes, data storage tapes and the like.

[0002]

2. Description of the Related Art In recent years, the progress of high density recording of magnetic recording media has been remarkable, for example, a ferromagnetic metal thin film formed on a non-magnetic support by a physical deposition method such as vacuum deposition or sputtering or a plating method. Metal thin film magnetic recording media are being developed and put to practical use. Specifically, Co
Vapor Deposition Tape (Japanese Patent Laid-Open No. 54-147010), C
Perpendicular magnetic recording medium made of o-Cr alloy
No. 134706) is known.

In a conventional coating type magnetic recording medium (a magnetic recording medium prepared by mixing magnetic powder in an organic polymer binder and coating it on a non-magnetic support), the thickness of the magnetic layer is as thick as about 2 μm or more, and Recording density is low and recording wavelength is long. On the other hand, the metal thin film (magnetic layer) in the ferromagnetic metal thin film type magnetic recording medium has a very thin thickness of 0.2 μm or less.

For this reason, the degree of influence of the surface condition of the non-magnetic support (base film) on the surface property of the magnetic recording layer is much larger in the metal thin film. That is, in the case of a ferromagnetic metal thin film type magnetic recording medium, the surface state of the non-magnetic support is directly expressed as surface irregularities of the metal thin film, which causes noise of the recording / reproducing signal. Therefore, it is desirable that the surface of the non-magnetic support be as smooth as possible.

On the other hand, from the viewpoint of handling such as film formation of the non-magnetic support, conveyance in the processing step, winding and unwinding, it is preferable that the film has excellent slipperiness. If the surface of the film is too smooth, the slipperiness between the film and the film is deteriorated and the surface is likely to be scratched, resulting in a decrease in product yield and an increase in manufacturing cost. Therefore, from the viewpoint of manufacturing cost, the surface of the non-magnetic support is preferably as rough as possible.

Further, in the case of a metal thin film type magnetic recording medium, in order to improve the adhesion between the metal thin film and the base film, the surface of the base film, which is called ion bombardment treatment, is activated by ions before forming the metal thin film. Process to convert. Then, when forming the metal thin film, the back surface of the film is cooled so that the film surface is heated at a considerably high temperature and the base film is not melted or physical properties such as mechanical properties are deteriorated. For this backside cooling, a method of winding a base film around a drum-shaped cooling body is usually adopted. At this time, both ends of the base film are masked so that a metal thin film is not formed on the drum surface.

Therefore, at both ends of the film roll that has gone through the vapor deposition process, the portions where the metal thin film is not formed by this masking are continuously activated in the longitudinal direction while being surface-activated by the ion bombardment treatment. Exist. Then, this portion comes into contact with the opposite surface side with a high force in a state of being rolled up in a roll shape, which easily causes blocking. When a metal thin film type magnetic recording medium is manufactured, a back coat layer and, if necessary, a top coat layer are provided after vapor deposition of a metal thin film, but if the blocking occurs in these processing steps, There is a problem that the film is likely to be cut or wrinkled, and the yield is significantly reduced. To prevent such blocking,
The surface of the non-magnetic support is preferably rough.

As described above, the surface of the non-magnetic support is required to be smooth from the viewpoint of electromagnetic conversion characteristics,
On the other hand, it is required to be rough from the viewpoints of handleability, manufacturing cost, and prevention of blocking.

In order to meet the above conflicting requirements,
A laminated film composed of two layers in which the surface of one layer is rougher than the surface of the other layer (for example, Japanese Patent Publication No. 1-2633).
No. 8) is proposed. However, in this laminated film, high protrusions of the rough surface layer are transferred to the surface of the flat surface layer,
There is a problem that the electromagnetic conversion characteristics of a magnetic recording medium deteriorate due to the push-up effect of the large particles added to the rough surface layer to the flat surface layer.

As a measure to prevent the surface smoothness from being deteriorated by the catalyst residue (fine particles) inside the base film, a germanium compound is used as a polymerization catalyst as a raw material for the smooth surface layer, and a specific amount of germanium and phosphorus are contained. Laminated film using polyester
No. 15695) has been proposed. However, even with this laminated film, bleed-out of foreign matters such as protrusions and oligomers from the surface of the rough surface occurs during film production or in the metal thin film processing step described above, and these foreign particles are smoothed in the smooth surface layer in each manufacturing step. It has a problem of reducing the sex.

[0011]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide a metal-deposited thin film type magnetic recording medium which is particularly excellent in blocking resistance, abrasion resistance and processability. Another object of the present invention is to provide a laminated polyester film having excellent electromagnetic conversion characteristics.

[0012]

The object of the present invention is, according to the present invention, a laminated film in which a polyester layer A, a polyester layer B and a coating layer C are laminated in this order,
The polyester layer B contains 0.001 to 1% by weight of the inactive particles B having an average particle size of 50 to 1000 nm, and the polyester layer A contains no inactive particles or more than the inactive particles contained in the polyester layer B. Also contains inert particles A having a small average particle diameter, and the coating layer C contains 1 to 40% by weight of a cellulose compound having a viscosity of a 3% by weight aqueous solution at 20 ° C. in the range of 10 to 1000 mPa · s. Achieved by the featured laminated polyester film.

Further, according to the present invention, in the laminated polyester film of the present invention, (a) the coating layer C comprises, in addition to the cellulose compound, (1) (meth) acrylic acid, polycarboxylic acid and polyhydric alcohol. 40 to 89% by weight of poly (meth) acrylic acid-polyester consisting of (2) 1 to 20% by weight of inert particles C having an average particle size of 10 to 80 nm,
(3) Containing 1 to 30% by weight of a surfactant,
(B) Poly (meth) acrylic acid-polyvalent carboxylic acid component / (meth) acrylic acid component molar ratio in the polyester is 1
/ 9-5 / 5, and alkyl methacrylates that do not contain acrylic acid component (A) is an epoxy group (M _A) 65 to
97 mol% and (B) an epoxy group-containing (meth) acrylate (M _B) 3 to 35 to consist mol%, (c) an inert particle B is crosslinked silicone resin, crosslinked acrylic resin,
Crosslinked polyester, aluminum oxide, titanium dioxide,
At least one kind of particles selected from the group consisting of silicon dioxide, kaolin, and clay, and (d) the ten-point average roughness (WRzB) of the surface of the polyester layer B in contact with the coating layer C is 30 to 300 nm. That (e) the surface roughness (WRaA) of the surface of the laminated polyester film on which the coating layer C is not laminated is in the range of 0.1 to 4 nm, and (f) the polyester layer B of the polyester layer A. The coating layer D is laminated on the surface not in contact with
The coating layer D contains 0.5 to 30% by weight of inert particles D having an average particle diameter of 10 to 50 nm and a volume shape factor of 0.1 to π / 6, and (g) a thickness of 2 μm or more and less than 8 μm. There is also provided, or (h) a laminated polyester film comprising the polyester constituting the polyester layer A and the polyester layer B being polyethylene terephthalate or polyethylene-2,6-naphthalate, and these laminated polyesters of the present invention are also provided. The film is preferably used as a support for a magnetic recording medium by providing a magnetic layer on the surface of the laminated polyester film on which the coating layer C is not laminated.

Furthermore, according to the present invention, there is provided a magnetic recording comprising the above-mentioned laminated polyester film of the present invention and a magnetic layer provided on the surface on which the coating layer C is not laminated. A medium, and as a preferred embodiment thereof, a magnetic recording medium in which the magnetic layer is a ferromagnetic metal thin film layer is also provided.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The laminated polyester film of the present invention is obtained by laminating a polyester layer B on one surface of a polyester layer A and laminating a coating layer C on the surface of the polyester layer B which is not in contact with the polyester layer A. .

Aromatic polyesters are preferably mentioned as the polyesters A and B constituting the polyester layers A and B, and they may be the same kind or different kinds.

As the aromatic polyester, polyethylene terephthalate, polyethylene isophthalate,
Examples thereof include polytetramethylene terephthalate, poly-1,4-cyclohexylene dimethylene terephthalate, and polyethylene-2,6-naphthalate (polyethylene-2,6-naphthalene dicarboxylate). Of these, polyethylene terephthalate and polyethylene-2,6-naphthalate are preferred.

Polyesters A and B used in the present invention
May be a homopolyester or a copolyester. In the case of copolyester, for example, polyethylene terephthalate or polyethylene-2,6-naphthalate copolymerization components include diethylene glycol, propylene glycol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol, polyethylene glycol, 1,4-cyclohexanediene. Other diol components such as methanol and p-xylylene glycol, adipic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid (provided that polyethylene-2,
6-naphthalate), 2,6-naphthalenedicarboxylic acid (however, in the case of polyethylene terephthalate), other dicarboxylic acid components such as 5-sodium sulfoisophthalic acid, oxycarboxylic acid components such as p-oxyethoxybenzoic acid, etc. Is mentioned. The amount of these copolymerization components is 20 mol% unless the effects of the present invention are impaired.
Hereafter, it is preferably 10 mol% or less.
Furthermore, a trifunctional or higher-functional compound such as trimellitic acid, pyromellitic acid, or pentaerythritol 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 copolymerization components in the case of polyesters other than polyethylene terephthalate and polyethylene-2,6-naphthalate may be considered in the same manner as above.

The polyester may further contain pigments, dyes, antioxidants, antistatic agents, light stabilizers and light-shielding agents (eg carbon black, titanium oxide, etc.) as long as the effects of the present invention are not impaired. Such additives can be contained as needed.

In the laminated polyester film of the present invention, the polyester layers A and B are preferably made of the same polyester, but they may be made of different polyesters. For example, a laminated film in which both layer A and layer B are made of polyethylene terephthalate or polyethylene-2,6-naphthalate is preferable, but layer A (or layer B) is polyethylene terephthalate and layer B (or layer A) is polyethylene-2, It may be a laminated film made of 6-naphthalate.

The polyester A forming the polyester layer A can be manufactured by a conventionally known method. For example, polyethylene terephthalate can be produced by a method in which terephthalic acid and ethylene glycol are esterified or dimethyl terephthalate and ethylene glycol are transesterified, and then the reaction product is polycondensed.

The polyester obtained by the above method (melt polymerization) can be made into a polymer having a higher degree of polymerization by a polymerization method in a solid state (solid phase polymerization), if necessary.

In this polymerization, known catalysts can be used, and as the transesterification catalyst in the melt polymerization, oxides of manganese, calcium, magnesium and titanium,
Chlorides, carbonates, carboxylates and the like are preferable, and particularly acetates, that is, manganese acetate, calcium acetate, magnesium acetate and titanium acetate are preferable.

Examples of polycondensation catalysts include antimony compounds, titanium compounds and germanium compounds.

As the antimony compound used as the polycondensation catalyst, antimony trioxide, antimony pentoxide,
Preferable examples include antimony acetate.

The titanium compound used as the polycondensation catalyst is preferably an organic titanium compound, and examples thereof include those described in JP-A-5-298670. More specifically, titanium alcoholate or organic acid salt, a reaction product of a tetraalkyl titanate and an aromatic polycarboxylic acid or an anhydride thereof, and the like can be exemplified.
Preferred specific examples include titanium tetrabutoxide, titanium isopropoxide, titanium oxalate, titanium acetate, titanium benzoate, titanium trimellitate, and a reaction product of tetrabutyl titanate and trimellitic anhydride.

Further, examples of the germanium compound used as the polycondensation catalyst include those described in Japanese Patent No. 2792068. More specifically, (a) amorphous germanium oxide, (b) crystalline germanium, (iii) a solution of germanium oxide dissolved in glycol in the presence of an alkali metal or an alkaline earth metal or a compound thereof, and (d) Examples thereof include a germanium oxide glycol solution prepared by dissolving germanium oxide in water, adding glycol to the solution, and distilling off water.

Further, it is preferable that the polyester A contains a phosphorus compound which is conventionally added in the polyester manufacturing process in order to maintain thermal stability. The phosphorus compound is not particularly limited, but orthophosphoric acid, phosphorous acid, trimethyl phosphate, triethyl phosphate, tri-phosphoric acid.
Preference is given to n-butyl phosphate.

The polyester layer A in the present invention may contain substantially no particles or may contain inert particles A. When the polyester layer A contains substantially no particles, excellent electromagnetic conversion characteristics can be obtained when used as a magnetic recording medium, and when particles are contained in a range that does not adversely affect the electromagnetic conversion characteristics, the running durability is improved. Can be planned. When the polyester layer A contains inert particles, the volume shape factor is 0.1 to π / 6, and the average particle size is 30 to
400 nm inactive particles (hereinafter, the inactive particles contained in the polyester layer A are referred to as the inactive particles A) are preferable.

Examples of preferable inert particles A include (1) heat-resistant polymer particles (for example, crosslinked silicone resin, crosslinked polystyrene, crosslinked acrylic resin, melamine-
Formaldehyde resin, aromatic polyamide resin, polyimide resin, polyamideimide resin, particles made of cross-linked polyester, etc.), (2) metal oxide (for example, aluminum oxide, titanium dioxide, silicon dioxide (silica),
(Magnesium oxide, zinc oxide, zirconium oxide, etc.), (3) metal carbonate (eg, magnesium carbonate, calcium carbonate, etc.), (4) metal sulfate (eg, calcium sulfate, barium sulfate, etc.), (5) Examples of the fine particles include one or more kinds of carbon (for example, carbon black, graphite, diamond, etc.), and (6) clay mineral (for example, kaolin, clay, bentonite, etc.). Among these, crosslinked silicone resin particles, crosslinked polystyrene resin particles, melamine-formaldehyde resin particles, polyamideimide resin particles, other aluminum oxide (alumina), titanium dioxide, silicon dioxide, zirconium oxide, synthetic calcium carbonate,
Fine particles of barium sulphate, diamond or kaolin are preferred. More preferably, crosslinked silicone resin particles, crosslinked polystyrene resin particles, other aluminum oxide (alumina), titanium dioxide, silicon dioxide,
Alternatively, they are fine particles made of calcium carbonate. You may use these 1 type (s) or 2 or more types.

The inert particles A have different average particle diameters.
When using more than one kind of particles, as the second and third particles (fine particles) having a small average particle size, for example, fine particles such as colloidal silica and alumina having a crystal morphology such as α, γ, δ and θ are preferably used. be able to. Further, among the particle species exemplified as the inert particles A having the average particle diameter dA, fine particles having a small average particle diameter can also be used as the second and third particles (fine particles).

The shape of the inert particles A has a volume shape factor (f) described later of 0.1 to π / 6, more preferably 0.2 to π.
/ 6, particularly preferably 0.4 to π / 6. The average particle diameter dA of the inert particles A is 30 to 400 n.
m, further 40 to 200 nm, especially 50 to 100 nm
Is preferred. If the average particle diameter dA is less than 30 nm, the improvement of the slip property of the film may be insufficient, while if it exceeds 400 nm, the electromagnetic conversion characteristics of the magnetic recording medium may be unfavorable.

When the inert particles A are contained in the polyester A, the content thereof is preferably 0.001 to 0.2% by weight, more preferably 0.01 to 0.1% by weight, based on the polyester layer A. , Particularly preferably 0.02
It is 0.06% by weight. If this amount is less than 0.001% by weight, the improvement of the slipperiness of the film may be insufficient, while if it exceeds 0.2% by weight, the electromagnetic conversion characteristics of the magnetic recording medium may be poor. It is not preferable because it exists.

The polyester B forming the polyester layer B in the present invention can be produced in the same manner as the polyester A. In that case, it is preferable to use the same catalyst as the polyester A as the catalyst used. Further, it is preferable to contain a phosphorus compound as in the case of the polyester A. The polyesters A and B preferably have a polymer intrinsic viscosity of 0.45 or more in view of the physical properties of the film (for example, Young's modulus). The upper limit of the intrinsic viscosity of the polymer is not particularly limited,
It is preferably at most 1.0, and the intrinsic viscosity of the polymer is particularly preferably in the range of 0.5 to 0.9.

The polyester layer B in the present invention is an inert particle having an average particle size larger than that of the inert particles A contained in the polyester layer A (hereinafter, the inert particles contained in the polyester layer B are referred to as the inert particles B). .) Must be included. The average particle size of the inert particles B is equal to that of the inert particles A.
If it is smaller than this, problems such as blocking may occur in the film manufacturing process and the metal thin film forming process. The average particle size (dB) of the inert particles B is 50 to 1,000 nm, preferably 100 to 800 nm, more preferably 150 to 7 nm.
00 nm, particularly preferably 200 to 600 nm.
The content of the inert particles B is determined by the polyester layer B
With respect to 0.001 to 1% by weight, preferably 0.005
˜0.8 wt%, more preferably 0.01 to 0.6 wt%, and particularly preferably 0.01 to 0.2 wt%.

As the preferable inert particles B, the same kind of particles as the above-mentioned inert particles A can be mentioned. This particle has 1
One kind or two or more kinds may be used, but from the viewpoint of resistance to falling off from the polyester layer B, a hydroxyl group that is more likely to improve the affinity by the reaction with the terminal carboxyl group of the polyester layer B is present on the particle surface. Particles present in large amounts are preferred, and at least one particle selected from crosslinked silicone resin, crosslinked acrylic resin, crosslinked polyester, aluminum oxide, titanium dioxide, silicon dioxide (silica), kaolin and clay is particularly preferred.

If the average particle size of the inert particles B is less than 50 nm or the content thereof is less than 0.001% by weight, the film winding property and blocking resistance will be poor. On the other hand, when the average particle size exceeds 1,000 nm or the content exceeds 1% by weight, the shape transfer of the protrusion to the opposite surface (the surface of the polyester layer A) or the protrusion from below the polyester layer A is caused. The electromagnetic conversion characteristics are deteriorated by pushing up.

The polyester layer B may contain, in addition to the inert particles B, second and third particles (fine particles) having an average particle size smaller than that of the inert particles B. The average particle size of the fine particles is preferably 5 to 450 nm, more preferably 10 to 400 nm, and particularly preferably 30 to 350 nm.
nm. The content of the second and third particles (fine particles) is preferably 0.00 based on the polyester layer B.
5 to 1% by weight, more preferably 0.01 to 0.7% by weight, and particularly preferably 0.02 to 0.5% by weight.

In the laminated polyester film of the present invention, various characteristics of the base film are less likely to deteriorate with time in the production of a magnetic tape, so that the surface opposite to the side on which the magnetic layer is provided, that is, the surface of the polyester layer B (polyester layer). A coating layer C is provided on the surface not in contact with A). The coating layer C needs to contain 1 to 40% by weight of a cellulose compound having a solution viscosity of a 3% aqueous solution in the range of 10 to 1000 mPa · s at 20 ° C.

The solution viscosity of the cellulose compound is 20 ° C.
Below, the solution viscosity of a 3% aqueous solution was measured using a B-type viscometer or an Ubbelohde-type viscometer (mainly used at 500 mPa · s or less and 100,000 mPa · s or more), at 10 mPa · s. If it does not satisfy the requirement, the blocking resistance becomes poor over time, and the electromagnetic characteristics of the magnetic recording medium deteriorate. In addition, 1000 mPa · s
If it exceeds, the solution viscosity will be too high, and it will be difficult to apply it to the surface of layer B. Even if it is possible, the cellulose component will not be dispersed uniformly, and rather the abrasion resistance will be poor in the film manufacturing process, and The object is transferred to the layer A side, which causes a dropout or the like.

The cellulose compound in the present invention is not particularly limited, and examples thereof include methyl cellulose, ethyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, carboxymethyl cellulose and the like, and methyl cellulose is particularly preferable.

The coating layer C in the present invention is required to contain a cellulose compound in an amount of 1 to 40% by weight. If the content is less than 1% by weight, blocking resistance and abrasion resistance are greatly deteriorated. If it exceeds 40% by weight, the compatibility with the binder is poor and the abrasion resistance is poor.

In addition to the cellulose compound, the coating layer C in the present invention contains 40 to 89% by weight of poly (meth) acrylic-polyester consisting of poly (meth) acrylic acid, polycarboxylic acid and polyhydric alcohol. Is preferred.

If the content of the poly (meth) acrylic-polyester is less than 40% by weight, a uniform film cannot be obtained, and if it exceeds 89% by weight, the blocking resistance is greatly reduced.

Poly (meth) acrylic used in the present invention
Polyester is a component of polycarboxylic acid /
(Meth) molar ratio of the acrylic acid component is 1 / 9-5 / 5, (meth) acrylic acid component, (A) an alkyl methacrylate containing no epoxy groups (M _A) 65 to 97 mol% and (B ) epoxy group-containing acrylic monomer (M _B) preferably contains 3 to 35 mol%.

The (meth) acrylic acid used herein by the present inventor means methacrylic acid, acrylic acid and their derivatives, and poly (meth) acrylic-polyester is modified with (meth) acrylic acid. And a poly (meth) acrylic component and a polyester component are bonded to each other, and examples thereof include a graft type and a block type. The poly (meth) acrylic-polyester is, for example, a radical initiator is added to both ends of the polyester to polymerize a (meth) acrylic acid monomer, or a radical initiator is added to a side chain of the polyester (meth). ) It can be produced by polymerizing an acrylic monomer, or by attaching a hydroxyl group to the side chain of an acrylic resin and reacting it with a polyester having an isocyanate group or a carboxyl group at the terminal. When this ratio is less than 1/9, the adhesion of the film to the polyester film tends to be insufficient, and when it exceeds 5/5, the abrasion resistance of the film and the oligomer suppressing effect of the base film are difficult to be exhibited. In other words, the polyester component of the poly (meth) acrylic-polyester secures the adhesiveness between the coating layer and the polyester film, and the poly (meth) acrylic component secures the abrasion resistance of the coating and the oligomer suppressing effect of the base film. To do.

[0048] Additionally, poly (meth) acrylic - constituting the polyester (meth) of acrylic acid component, (A) an alkyl methacrylate containing no epoxy groups (M _A)
Examples of the alkyl group applicable to are preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, a 2-ethylhexyl group, a cyclohexyl group and the like. Also,
Preferable examples of the epoxy group-containing acrylic monomer (MB) ( _B ) include glycidyl acrylate, glycidyl methacrylate, and allyl glycidyl ether. On the other hand, the polyester resin component constituting the poly (meth) acrylic-polyester is composed of the following polyvalent carboxylic acid or its ester-forming derivative and polyhydric alcohol or its ester-forming derivative. Examples of polycarboxylic acid components include terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride, 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, sebacic acid, trimellitic acid, and pyromellitic acid. 5,
-Sodium sulfoisophthalic acid and the like. It is preferable to synthesize a copolyester resin by using two or more of these acid components. It is also possible to use hydroxycarboxylic acids such as maleic acid, itaconic acid and the like and p-hydroxybenzoic acid and the like which are unsaturated polybasic acid components in a small amount. The polyhydric alcohol component may be ethylene glycol, 1,4-butanediol, diethylene glycol, dipropylene glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, xylene glycol, dimethylolpropane, poly (ethylene oxide). ) Glycol, poly (tetramethylene oxide) glycol and the like. Two or more kinds of these monomers can be used for copolymerization. Among these, it is particularly preferable to use 1,4-cyclohexanedimethanol in terms of achieving both surface flatness and heat resistance.

Further, the coating layer C contains 1 to 20 inert particles C having an average particle size of 10 to 80 nm in addition to the cellulose compound.
It is preferable to contain it by weight.

The inert particles C to be contained in the coating layer C are not particularly limited, but those having a relatively low specific gravity, which does not easily settle in the coating liquid, are preferable. For example, organic particles made of a resin such as crosslinked silicone resin, acrylic resin, polystyrene, melamine-formaldehyde resin, aromatic polyamide resin, polyamideimide resin, crosslinked polyester, wholly aromatic polyester, silicon dioxide (silica),
Inorganic particles made of calcium carbonate or the like are preferable. Of these, crosslinked silicone resin particles, acrylic resin particles, silica particles, core-shell organic particles (core: crosslinked polystyrene, shell: polymethylmethacrylate particles, etc.) are preferable.

The average particle diameter (dC) of the inert particles C is 10
-80 nm, preferably 12-65 nm, more preferably 15-55 nm. If the average particle size is less than 10 nm, the improvement of the slipperiness of the film may be insufficient, while if it exceeds 80 nm, the electromagnetic conversion characteristics of the magnetic recording medium may be unfavorable.

The content of the inactive particles C is 1 to 20% by weight, preferably 4 to 20% by weight based on the coating layer C (solid content of the coating liquid).
It is 18% by weight, more preferably 5 to 15% by weight.
If the content is less than 1% by weight, the improvement of the slipperiness of the film may be insufficient, whereas if it exceeds 20% by weight, the electromagnetic conversion characteristics of the magnetic recording medium may become poor, which is preferable. Absent.

Further, the coating layer C preferably contains 1 to 30% by weight of a surfactant in addition to the cellulose compound. As the surfactant in the coating layer C, any of anionic type, cationic type and nonionic type may be used, and among them, the nonionic type is preferable. Examples of the nonionic surfactant include ester type, ether type, and alkylphenol type. The ratio of the surfactant in the film is 1
The content is preferably not less than 30% by weight and more preferably not less than 2% by weight and not more than 28% by weight. If it is less than 1% by weight, the coatability will be extremely deteriorated and the running durability with the head when used as a magnetic recording medium will be insufficient.
If it exceeds 5% by weight, the heat resistance of the coating layer decreases, which is not preferable.

If desired, other components such as stabilizers, dispersants, UV absorbers, thickeners, release agents, etc. may be added to the coating layer C as long as the effects of the present invention are not impaired. You can

The ten-point average roughness (WRzB) of the surface of the polyester layer B which is not in contact with the polyester layer A
Is 30 to 300 nm, preferably 40 to 250 nm, and particularly preferably 50 to 200 nm. When WRzB is 30 nm or less, the handleability of the laminated film is poor, sufficient productivity cannot be improved, and the blocking improving effect is insufficient. On the other hand, when it exceeds 300 nm, the shape transfer of the protrusion to the surface on the opposite side where the magnetic layer is provided (the surface of the polyester layer A) becomes large, which may impair the electromagnetic conversion characteristics, which is not preferable. The surface roughness (WRzB) can be adjusted by the particle size and amount of the inert particles C contained in the coating layer C and / or the particle size and amount of the inert particles B contained in the polyester layer B.

On the other hand, the laminated polyester film of the present invention is improved in various characteristics when used as a magnetic tape.
The coating layer D is preferably provided on the surface on which the magnetic layer is provided, that is, the surface of the polyester layer A (the surface not in contact with the polyester layer B).

The coating layer D has an average particle size of 10 to 50 n.
m, the volumetric shape factor of 0.1 to π / 6, and the inert particles C of 0.
It is preferable to contain 5 to 30% by weight.

As the resin forming the coating layer D, for example, water-based polyester resin, water-based acrylic resin, water-based polyurethane resin and the like are preferably mentioned, and water-based polyester resin is particularly preferable.

The water-based polyester resin has acid components such as isophthalic acid, phthalic acid, 1,4-cyclohexanedicarboxylic acid, 2,6-naphthalenedicarboxylic acid,
4,4'-diphenyldicarboxylic acid, adipic acid, sebacic acid, dodecanedicarboxylic acid, succinic acid, sodium 5-sulfoisophthalate, potassium 2-sulfoterephthalate, trimellitic acid, trimesic acid, trimellitic acid monopotassium salt, At least one selected from the group consisting of polyvalent carboxylic acids such as p-hydroxybenzoic acid, and glycol components such as ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 1 , 4-cyclohexanedimethanol, p-xylylene glycol,
Those mainly composed of at least one selected from the group consisting of polyhydric hydroxy compounds such as dimethylolpropane and an ethylene oxide adduct of bisphenol A are preferably used. Further, a graft polymer or a block copolymer in which an acrylic polymer chain is bonded to a polyester chain, or two kinds of polymers have a specific physical constitution (IPN (interpenetrating polymer network) within a micro particle).
Mold, core shell mold, etc.) may be used. As the water-based polyester resin, a type that dissolves, emulsifies, and finely disperses in water can be freely used, but a type that emulsifies and finely disperses in water is preferable. Further, since these impart hydrophilicity, for example, sulfonate group, carboxylate group,
A polyether unit or the like may be introduced.

The inert particles D contained in the coating layer D are not particularly limited, but are unlikely to settle in the coating liquid,
Those having a relatively low specific gravity are preferable. For example, organic particles made of resins such as crosslinked silicone resin, acrylic resin, polystyrene, melamine-formaldehyde resin, aromatic polyamide resin, polyamideimide resin, crosslinked polyester, wholly aromatic polyester, silicon dioxide (silica), calcium carbonate, etc. The following inorganic particles are preferred. Of these, crosslinked silicone resin particles, acrylic resin particles, silica particles, core-shell organic particles (core: crosslinked polystyrene, shell: polymethylmethacrylate particles, etc.) are preferable.

The average particle diameter (dD) of the inert particles D is 1
It is 0 to 50 nm, preferably 12 to 45 nm, more preferably 15 to 40 nm. This average particle size is 10 nm
If it is less than 50 nm, the improvement of the slipperiness of the film may be insufficient, while if it exceeds 50 nm, the electromagnetic conversion characteristics of the magnetic recording medium may become poor, which is not preferable.

The shape of the inert particles D has a volume shape factor (f) described later of 0.1 to π / 6, preferably 0.2 to π.
/ 6, and more preferably 0.4 to π / 6.

The shape of particles having a volume shape factor (f) of π / 6 is a sphere (a true sphere). That is, those having a volume shape factor (f) of 0.4 to π / 6 substantially include spheres, true spheres, and elliptical spheres such as rugby balls, and are preferable as the inert particles D. Particles having a volume shape factor (f) of less than 0.1, for example, flaky particles,
It is not preferable because the running durability will be reduced.

The content of the above-mentioned inert particles D is such that the coating layer D
0.5 to 30% by weight, preferably 2 to 20% by weight, more preferably 3 to 10% by weight, based on (solid content of coating liquid).
Is. If this content is less than 0.5% by weight, the improvement of the slipperiness of the film may be insufficient, while 30
When the content exceeds the weight%, the electromagnetic conversion characteristics of the magnetic recording medium may be deteriorated, which is not preferable.

The laminated polyester film in the present invention has a surface roughness on the surface of the polyester layer A (the surface which is not in contact with the polyester layer B and is the surface of the coating layer D when the coating layer D is provided). (WRaA) is 0.1
It is preferably 4 nm. More preferably 0.2
.About.3.5 nm, particularly preferably 0.3 to 3.0 nm, especially 0.4 to 2.5 nm. This WRaA is 0.1n
When it is less than m, the slipperiness is poor and it is extremely difficult to produce a film. On the other hand, when WRaA exceeds 4 nm, the electromagnetic conversion characteristics are deteriorated, which is not preferable.

The surface roughness (WRaA) is adjusted by the particle size and amount of the inert particles D contained in the coating layer D and / or the particle size and amount of the inert particles A contained in the polyester layer A. You can

The total thickness of the laminated polyester film in the present invention is usually 2 μm or more and less than 8 μm, preferably 2.5 to 7.5 μm. Regarding the thickness constitution of the polyester layer A and the polyester layer B, the thickness of the layer B is preferably 1/50 to 1/2 of the total thickness of the laminated film, more preferably 1/30 to 1/3, and particularly preferably 1/20. ~ 1/4
Is. The thickness of the coating layer C is usually 1 to 100 nm, preferably 2 to 50 nm, more preferably 3 to 10 nm,
Particularly preferably, it is 3 to 8 nm.

The laminated polyester film of the present invention can be produced according to a method known in the art or accumulated in the art. Among them, the laminated structure of the polyester layer A and the polyester layer B is preferably produced by a coextrusion method, and the lamination of the coating layer C and the coating layer D is preferably performed by a coating method.

For example, a biaxially oriented polyester film will be described. A (partially saponified) ester wax and an inert particle B in or before the extrusion die (generally, the former is called a multi-manifold system, the latter is called a feed block system). The polyester B containing finely dispersed and contained therein and the polyester A containing the inert particles A as required are respectively subjected to high precision filtration, and then laminated and composited in a molten state to obtain a laminated structure having the above-mentioned preferable thickness ratio. After that, the film is coextruded from the die at a temperature of melting point (Tm) to (Tm + 70) ° C., and then rapidly cooled and solidified by a cooling roll at 40 to 90 ° C. to obtain an unstretched laminated film. Then, the unstretched laminated film was subjected to a conventional method in a uniaxial direction (longitudinal direction or transverse direction) at a temperature of (Tg-10) to (Tg + 70) ° C. (however, Tg: glass transition temperature of polyester) of 2.5 to. 8.0 times magnification, preferably 3.0 to 7.5
2 times at a temperature of (Tg) to (Tg + 70) ° C. in a direction perpendicular to the above-described stretching direction (the second-stage stretching is in the transverse direction when the first-stage stretching is in the longitudinal direction). .5
Stretching is performed at a draw ratio of ˜8.0 times, preferably a draw ratio of 3.0 to 7.5 times. Furthermore, if necessary, the vertical and / or
Alternatively, it may be stretched again in the transverse direction. That is, two steps,
It is advisable to carry out stretching in three stages, four stages or multiple stages. The total draw ratio is usually 9 times or more, preferably 10 to 35 times,
It is more preferably 12 to 30 times.

Further, the biaxially oriented film has (Tg +
Excellent dimensional stability is imparted by heat-fixing crystallization at a temperature of 70) to (Tm-10) ° C, for example, in the case of a polyethylene terephthalate film, at 180 to 250 ° C. At that time, the heat setting time is preferably 1 to 60 seconds.

In the production of the laminated polyester film, the polyesters A and B may optionally contain additives other than the above-mentioned inert particles, such as stabilizers, colorants, and specific resistance adjusting agents for molten polymers. .

The lamination of the coating layer D on the polyester layer A and the lamination of the coating layer C on the polyester layer B in the present invention are preferably carried out by a method of applying an aqueous coating liquid.

It is preferable that the coating is performed on the surfaces of the polyester layer A and the polyester layer B before the final stretching treatment, and after the coating, the film is stretched at least uniaxially. The film is dried before or during this stretching. Among them, the application is unstretched laminated film or longitudinal (uniaxial)
It is preferable to perform it on a stretched laminated film, particularly a longitudinal (uniaxial) stretched laminated film. The coating method is not particularly limited, but examples thereof include a roll coating method and a die coating method.

The solid content concentration of the coating solution, especially the aqueous coating solution, is
0.2 to 8% by weight, more preferably 0.3 to 6% by weight, especially 0.
It is preferably from 5 to 4% by weight. Then, other components, for example, other surfactants, stabilizers, dispersants, ultraviolet absorbers, thickeners, etc. can be added to the aqueous coating liquid within a range that does not impair the effects of the present invention.

In the present invention, in order to improve various performances such as head touch as a magnetic recording medium and running durability, and at the same time achieve thinning, the Young's modulus of the laminated film is set in the longitudinal and lateral directions. And usually 45
00N / mm ² or more and 6000 N / mm ² or more, preferably 4800N / mm ² or more and 6800N / mm ²
Or more, more preferably 5500N / mm ² or more and 8000 N / mm ² or more, particularly preferably 5500N /
mm ² or more and 10,000 N / mm ² or more.

The crystallinity of the polyester layers A and B is preferably 30 to 50% when the polyester is polyethylene terephthalate and 28 to 38% when the polyester is polyethylene-2,6-naphthalate. If both are below the lower limit, the heat shrinkage rate will be large, while if it is above the upper limit, the abrasion resistance of the film will be deteriorated and white powder tends to be generated when sliding on the surface of the roll or the guide pin.

According to the present invention, a laminated polyester film in which a polyester layer B is laminated on one surface of the polyester layer A, a coating layer C and the polyester are formed on the surface of the polyester layer B (the surface not in contact with the polyester layer A). Surface of layer A (surface not in contact with polyester layer B)
There is also provided a magnetic recording medium using each of the laminated polyester films having the coating layer D laminated thereon as a base film.

The embodiment for producing a magnetic recording medium from the laminated polyester film of the present invention is as follows.

The laminated polyester film of the present invention contains iron, cobalt, nickel, chromium or a main component thereof on the surface of the polyester layer A, preferably the coating layer D, by a method such as vacuum deposition, sputtering and ion plating. It is particularly useful as a base film of a magnetic recording medium on which a ferromagnetic metal thin film layer (magnetic layer) made of an alloy or oxide is formed. The thickness of the metal thin film layer is 100-
It is preferably 300 nm.

Further, in the laminated polyester film of the present invention, a protective layer such as diamond-like carbon (DLC) and a fluorine-containing carboxylic acid type lubricating layer are sequentially provided on the surface of the ferromagnetic metal thin film layer according to the purpose, application and need. Further, if necessary, by providing a back coat layer on the surface of the polyester layer B opposite to the magnetic layer by a known method,
In particular, it is preferable to use it as a vapor deposition magnetic recording medium for high density recording, which has excellent output in a short wavelength region, electromagnetic conversion characteristics such as S / N and C / N, and has little dropout and error rate. This vapor-deposited magnetic recording medium is used for analog signal recording Hi8, digital signal recording digital video cassette recorder (DVC), data 8 mm, DDSI.
It is extremely useful as a magnetic tape medium for V, and is particularly suitable for use in digital video tape applications because excellent results can be obtained. It is also suitable for use as a data storage tape because excellent results can be obtained.

Further, the laminated polyester film of the present invention has the polyester layer A, preferably the coating layer D, on the surface thereof,
Needle-shaped fine magnetic powder (metal powder) containing iron or iron as the main component
Is uniformly dispersed in a binder such as polyvinyl chloride or vinyl chloride / vinyl acetate copolymer, and coated so that the magnetic layer has a thickness of 1 μm or less, preferably 0.1 to 1 μm. Is the opposite surface, ie
By providing a backcoat layer on the surface of the coating layer C by a known method, the output, S / N, C /
A metal-coated magnetic recording medium for high density recording, which has excellent electromagnetic conversion characteristics such as N and has a small dropout and error rate, can be obtained. In addition, a non-magnetic layer containing fine titanium oxide particles or the like as an underlayer of the magnetic layer containing the metal powder is dispersed in the same organic binder as the magnetic layer on the surface of the polyester layer A or the coating layer D, if necessary. It can also be painted. This metal coated magnetic recording medium is used for analog signal recording 8 mm video, Hi8, β-cam SP, W-VHS, digital signal recording digital video cassette recorder (DVC), data 8 mm, D
It is extremely useful as a magnetic tape medium for DSIV, digital β cam, D2, D3, SX and the like.

Further, in the laminated polyester film of the present invention, acicular fine magnetic powder such as iron oxide or chromium oxide or plate-like fine magnetic powder such as barium ferrite is formed on the surface of the polyester layer A, preferably the coating layer D. It is evenly dispersed in a binder such as polyvinyl chloride or vinyl chloride / vinyl acetate copolymer, and coated so that the thickness of the magnetic layer is 1 μm or less, preferably 0.1 to 1 μm. By providing a back coat layer on the surface opposite to the magnetic layer by a known method,
In particular, an oxide-coated magnetic recording medium for high density recording having excellent output in a short wavelength region, electromagnetic conversion characteristics such as S / N and C / N, and low dropout and error rate can be obtained. In addition, if necessary, a non-magnetic layer containing fine titanium oxide particles or the like as an underlayer of the oxide powder-containing magnetic layer is formed on the surface of the polyester layer A or the coating layer D in the same organic binder as the magnetic layer. It can also be dispersed and coated. This oxide-coated magnetic recording medium is useful as an oxide-coated magnetic recording medium for high-density recording such as a QIC for a data streamer for digital signal recording.

As described above, the magnetic recording medium of the present invention is formed by applying a solution containing solid fine particles and a binder, and various additives as necessary, on the surface opposite to the magnetic layer forming surface. Although a back coat layer may be provided, known solid fine particles, binders, and additives may be used and are not particularly limited. The thickness of the back coat layer is preferably 0.3 to 1.5 μm.

The above-mentioned W-VHS is an analog HDTV signal recording VTR, and DVC is a digital HDTV.
It is applicable for recording TV signals. Therefore, the laminated polyester film of the present invention is
It can be said that it is a very useful base film for a magnetic recording medium for a TV-compatible VTR.

[0085]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In addition, "parts" and "%" in Examples and Comparative Examples are parts by weight and% by weight, unless otherwise specified. The physical property values and characteristics in the present invention are measured and defined by the following methods.

(1) Intrinsic viscosity Determined from the value measured at 35 ° C. in an orthochlorophenol solvent.

(2) Solution viscosity of cellulose compound (mP
a.s) Using a B type viscometer and / or an Ubbelohde viscometer, 2
Solution viscosity is measured for a 3% aqueous solution at 0 ° C.

(3) Average particle size (I) of particles (Average particle size:
Shimadzu Corporation “CP-50 type Centrifuge particle size analyzer (Centrifuga
l Particle Size Analyzer) ”. The particle diameter "equivalent sphere diameter" corresponding to 50 mass% is read from the integrated curve of particles having respective particle diameters calculated based on the obtained centrifugal sedimentation curve and the abundances thereof, and this value is used as the average particle diameter (nm). ) (“Particle size measurement technology”, published by Nikkan Kogyo Shimbun, 1975, pages 242 to 247).

(4) Average particle size (II) of particles (Average particle size:
Particles having an average particle diameter of less than 60 nm that form small protrusions are measured by a light scattering method. That is, the product name "NICOMP MODEL 270 SUBMICRON PARTICLE SIZER" manufactured by Nicomp Instruments Inc.
The average particle diameter (nm) is defined as the "equivalent spherical diameter" of the particles at 50% of all the particles obtained by.

(5) Volumetric shape factor (f) A photograph of each particle was taken with a scanning electron microscope at a magnification corresponding to the size used, and an image analysis processor Luzex 500 (manufactured by Nippon Regulator Co., Ltd.) was used. The maximum diameter of the projection surface is obtained as the average particle diameter (D) (μm) of the particles, and the volume (V) (μm ³ ) of the particles is calculated and calculated by the following formula (I).

[0091]

[Equation 1] f = V / D ³ (I)

(6) Thickness of polyester layers A and B, and
And overall film thickness Random thickness of the entire film with a micrometer
10 points are measured and the average value is used. Polyester layer
About the layer thickness of A and B, the layer thickness of the thin polyester layer
Is measured by the method described below, and the thick polyester layer
Layer thickness is a coating layer and a polyester layer thinner than the total thickness
Calculate by subtracting the layer thickness of. That is, the secondary ion mass
Using an analyzer (SIMS), the depth from the surface layer excluding the coating layer
The highest of the particles in the film in the range of 5,000 nm
Metal element (M ⁺) And polyester
Hydrocarbons (C⁺) Concentration ratio (M⁺/ C⁺) Is the particle concentration
Then, from the surface to the depth of 5,000 nm, analyze in the thickness direction.
To do. At the surface layer, the particle concentration is low due to the interface called the surface.
In addition, the particle concentration increases as the distance from the surface increases. Book
In the case of the invention, once the particle concentration once reached a stable value of 1,
There is a case where it rises to a stable value of 2 and a case where it decreases monotonically.
is there. Based on this distribution curve, in the former case, (stable value
1 + stable value 2) / 2 with a depth giving a particle concentration of
In the latter case, the depth at which the particle concentration becomes 1/2 of the stable value 1
(This depth is deeper than the depth that gives a stable value of 1)
The thickness (μm) of the thin polyester layer. Measurement
The conditions are as follows.

(A) Measuring device Secondary ion mass spectrometer (SIMS); manufactured by Perkin Elmer Inc., "6300" (b) Measuring condition Primary ion species: O ²⁺ primary ion accelerating voltage : 12 KV Primary ion current: 200 nA Raster area: 400 μm □ Analysis area: Gate 30% Measuring vacuum degree: 6.0 × 10 ⁻⁹ Torr E-GUNN: 0.5 KV-3.0 A

If the most abundant particles in the range of 5,000 nm from the surface layer are organic polymer particles other than silicone resin, it is difficult to measure with SIMS, so FT-IR (Fourier transform red) is performed while etching from the surface. Outer layer spectroscopy) and, depending on the particle, the same concentration distribution curve as above is measured by XPS (X-ray photoelectric spectroscopy) or the like to determine the layer thickness (μm).

(7) Thickness of coating layer C A small piece of the film was fixed and molded with an epoxy resin, and an ultrathin section (cut in parallel with the film flow direction) having a thickness of about 600 angstrom was prepared with a microtome.
A transmission electron microscope (Hitachi, Ltd .:
H-800 type), and the thickness (nm) of the coating layer is obtained by searching the boundary surface of the coating layer C.

(8) Surface Roughness A non-contact three-dimensional roughness meter manufactured by WRa WYKO Co., Ltd., trade name "TOPO-
3D ", measurement magnification 40 times, measurement area 242μm ×
The measurement was performed under the condition of 239 μm (0.058 mm ² ) to obtain a surface roughness profile (original data). The center plane average roughness (WRa) defined by the following equation is obtained by the surface analysis using the software with a built-in roughness meter.

[0097]

[Equation 2]

Here, Zjk is the measurement direction (242 μ
m) and the direction orthogonal to it (239 μm) are divided into M and N, respectively, j-th and k-th directions.
It is the height on the three-dimensional roughness chart at the second position. Ten-point average roughness WRz From the data obtained by measuring under the same conditions using the same measuring device as above, the surface analysis by the software of the same roughness meter included 5 points from the highest peak (Hp) and the valley. (Hv)
The average value obtained by taking 5 points from the lower one is determined as WRz.

[0099]

[Equation 3]

(9) Young's modulus Using a tensile tester manufactured by Toyo Baldwin Co., Ltd., trade name "Tensilon", in a room adjusted to a temperature of 20 ° C. and a humidity of 50%, a length of 300 mm and a width of 12.7.
The mm sample film is pulled at a strain rate of 10% / min, and is calculated by the following equation (V) using the first linear portion of the tensile stress-strain curve.

[0101]

E = Δσ / Δε (V) where E is Young's modulus, Δσ is the stress difference due to the original average cross-sectional area between the two points on the straight line, and Δε is between the same two points. It is the strain difference.

(10) Winding property After optimizing the winding condition at the slit, the width 600
mm × 12,000m size, 30 rolls, speed 1
The film is slit at a rate of 00 m / min, and a roll having no bumps, protrusions, or wrinkles is regarded as a good product on the film surface after slitting, and the winding property is evaluated according to the following criteria. ⊚: 28 or more non-defective rolls ○: 25 to 27 non-defective rolls ×: 24 or less non-defective rolls

(11) Scraping resistance A film slit to a width of 12.7 mm was used, and the diameter was 2 mm.
Angle of the SUS guide pin with respect to the surface of the coating layer C by 40 °
Under the conditions of, tension 30g, speed 150m / min 5
The width of accumulation of the shavings adhering to the guide pins when traveling 0 m is obtained by taking a micrograph (× 160).
The width of the accumulated shavings is judged as follows. The smaller the accumulation width of the shavings is, the more excellent the shaving property is. ◯: less than 0.30 mm Δ: 0.30 mm or more less than 0.50 mm x: 0.50 mm or more

(12) Anti-blocking property The side of the two films on which the coating layer C is formed and the other surface (A
Surface) and are left to stand for 10 hours under no load in an atmosphere of 35 ° C. × 80% RH. Then, in the same atmosphere, under a load of 15 N / mm ² , for 24 hours, 5c
Two films that were cut into m-width strips and blocked with a tensile tester were peeled off at a speed of 100 m / min, and the A surface of the film was observed in 5 fields of view at 950 times with a differential interference microscope. Evaluate with. ◯: No transfer foreign matter or peeling of the coating layer was observed. Δ: Partial peeling of the transfer foreign matter or coating layer was observed. ×: There was peeling of the transfer foreign matter or coating layer on one side, or breakage occurred.

(13) Manufacture of magnetic tape and evaluation of characteristics (electromagnetic conversion characteristics) On the surface of the coating layer C of the laminated polyester film, 0.2 μm of a ferromagnetic thin film of 100% cobalt was deposited by a vacuum deposition method.
Two layers (each layer thickness is about 0.1 μm) are formed to have a thickness of m. A diamond-like carbon (DLC) film and a fluorine-containing carboxylic acid-based lubricating layer are sequentially provided on the surface of the formed ferromagnetic thin film, and a back coat layer is provided on the surface of the polyester layer A by a known method. After that, it was slit into a width of 8 mm and loaded into a commercially available 8 mm video cassette. Then, the characteristics (C / N) of the tape are measured using the following commercially available equipment. (A) Equipment used 8 mm video tape recorder, manufactured by Sony Corporation, product name "EDV-6000" manufactured by Shibasoku Co., Ltd., noise meter (b) Measuring method Recording signal of wavelength 0.5 μm (frequency about 7.4 MHz) Then, the ratio of the values of 6.4 MHz and 7.4 MHz of the reproduced signal is taken as the C / N of the tape, and the C / N of the commercially available 8 mm video vapor deposition tape is taken as 0 dB, and the relative values are evaluated as follows. ◎: Compared with commercial tape +3 dB or more ○: Compared with commercial tape +2 dB or more △: Compared with commercial tape -2 dB or more to less than +2 dB ×: Compared with commercial tape less than -2 dB

[Example 1] To a mixture of 100 parts of dimethyl 2,6-naphthalenedicarboxylate and 70 parts of ethylene glycol, 0.025 part of manganese acetate tetrahydrate as an ester exchange catalyst was added, and the internal temperature was 150 ° C. The transesterification reaction was carried out while gradually increasing the temperature. When the transesterification reaction reached 95%, phosphorous acid was added to 0.0
After adding 1 part and stirring sufficiently, ethylene glycol 2.
0.014 parts of a liquid (titanium content: 11% by weight) obtained by reacting 0.8 parts of trimellitic anhydride with 0.65 parts of tetrabutyl titanate in 5 parts was added. Further, 0.03% (based on the polymer) of spherical silica having an average particle diameter of 60 nm (volume shape factor 0.5) was added as a lubricant (inert particle A) and sufficiently stirred, and then the reaction product was polymerized into a reactor. And polycondensation was performed under high temperature vacuum (final internal temperature 295 ° C.) to obtain polyethylene 2,6-naphthalate (PEN) (resin A1) for polyester A having an intrinsic viscosity of 0.60.

Further, a transesterification reaction was carried out in the same manner as above, and when the transesterification reaction reached 95%, 0.01 part of phosphorous acid was added as a stabilizer, and the mixture was thoroughly stirred and then mixed. 0.03 parts of antimony oxide was added. After sufficiently distilling water mixed in the system, silicone particles having an average particle diameter of 300 nm and θ-alumina having an average particle diameter of 100 nm were used as lubricants (inert particles B) in the resin in an amount of 0.05% and After 0.2% addition and sufficient stirring, the reaction product was then transferred to a polymerization reactor and polycondensed under high temperature vacuum (final internal temperature 295 ° C.) to obtain an intrinsic viscosity of 0.
Polyethylene-2,6-naphthalate (PEN) (resin B1) for 70 polyester layers B was obtained. At this time, the residual amount of antimony in this polymer was 250 ppm.

The obtained resin A1 and resin B1 were dried at 170 ° C. for 6 hours and then fed to two extruders,
Melting at a melting temperature of 280 to 300 ° C., average opening 11
After high-precision filtration with a μm steel wire filter, use a multi-manifold type co-extrusion die to produce a polyester layer A
Polyester layer B is laminated on one side of and cooled rapidly to a thickness of 8
An unstretched laminated polyester film of 9 μm was obtained.

The obtained unstretched film is preheated, and the film temperature is 135 ° C. between low speed and high speed rolls.
It was stretched 6 times and rapidly cooled to obtain a longitudinally stretched film. Then, an aqueous coating solution (total solid content concentration of 1.0%) having the composition (solid content conversion) shown below was applied to the A layer side of the longitudinally stretched film by a kiss coating method so that the thickness of the coating layer D after drying was 8 nm. Was applied to.

<Solid Content Composition of Coating Liquid (For Coating Layer D)> Binder: Poly (meth) acrylic-polyester
60% Polyester part; terephthalic acid (55 mol%), isophthalic acid (40 mol%), 5-sodium sulfoisophthalic acid (5 mol%) / ethylene glycol (80 mol%), cyclohexanedimethanol (20 mol%)・ Poly (meth) acrylic part; methyl methacrylate (7
5 mol%), glycidyl methacrylate (20 mol%), n-butyl acrylate (5 mol%)-Mole ratio of polycarboxylic acid component / (meth) acrylic acid component = 3/7 Inactive particles C: Acrylic filler (Average particle size 30 nm)
(Volume shape factor 0.40) (Nippon Shokubai Co., Ltd., Eposter) 7% Surfactant X: (Nippon Yushi Co., Ltd., Nonion NS-20)
8.5) 3% surfactant Y: (Nonion NS-24, manufactured by NOF CORPORATION)
0) 30% At the same time, the thickness of the coating layer C after drying an aqueous coating liquid (total solid content concentration of 2.0%) having the composition (solid content conversion) shown below on the B layer side is 15 nm. As applied.

Solid content composition of coating liquid ・ Cellulose compound: 30% (methyl cellulose (Shin-Etsu
Made by Chemical Industry Co., Ltd., Metroze SM25)) ・ Binder (poly (meth) acrylic-polyester
Le): 60% -Polyester part; terephthalic acid (55 mol%), iso
Phthalic acid (40 mol%), 5-sodium sulfoisophthalate
Talic acid (5 mol%) / ethylene glycol (80 mol
%), Cyclohexanedimethanol (20 mol%) -Acrylic part; methyl methacrylate (90 mol%),
Glucidyl methacrylate (10 mol%) ・ Mole of polycarboxylic acid component / (meth) acrylic acid component
Ratio = 6/4 -Acrylic particles: 5% (average particle size 50 nm) -Surfactant: 5% (Nonion NS-20, manufactured by NOF CORPORATION)
8.5) Then, it was supplied to the stenter, and it was fed at 155 ° C in the horizontal direction for 5.
It was stretched 7 times. The obtained biaxially stretched film was
Heat set with hot air at ℃ for 4 seconds, and with a total thickness of 4.4 μm,
Laminated biaxially oriented polyester with a thickness of 0.6 μm of ester layer B
I got a tell film. Polyester layer of this film
About the thickness of A and B, the discharge amount of the two extruders
I adjusted more. Measured from the surface of this film on the coating layer C side
The determined surface roughness WRa is 1.3 nm.
Young's modulus is 5500 N / mm in the vertical direction ², Lateral direction 10,5
00N / mm²Met. Other of this laminated film
Characteristics and ferromagnetic thin film deposition type magnet using this film
The characteristics of the air tape are shown in Table 1.

[Examples 2 and 3] A laminated polyester was prepared in the same manner as in Example 1 except that the kind, the average particle size and the addition amount of the inert particles in the polyester layers A and B were changed as shown in Table 1. I got a film. Table 1 shows the characteristics of the obtained film and the characteristics of the ferromagnetic thin film deposition type magnetic tape using the film.

[Example 4] A laminated polyester film was obtained in the same manner as in Example 3 except that the solution viscosity of the cellulose contained in the coating layer C was changed as shown in Table 1. Table 1 shows the characteristics of the obtained film and the characteristics of the ferromagnetic thin film deposition type magnetic tape using this film.

[Example 5] Polyester layers A and B were prepared in the same manner as in Example 1 except that dimethyl 2,6-naphthalenedicarboxylate used for the polymerization of polyesters A and B was changed to the same molar amount of dimethyl terephthalate. To obtain polyethylene terephthalate (PET). The intrinsic viscosity was 0.60 for the polyester layer A resin and 0.67 for the polyester layer B resin.

After drying these resins at 170 ° C. for 3 hours, the thickness of each layer was adjusted in the same manner as in Example 1.
An unstretched laminated thermoplastic resin film having a thickness of 89 μm was obtained.

The obtained unstretched film was preheated, and the film temperature was 100 ° C. between rolls of low speed and high speed.
It was stretched 3 times and rapidly cooled to obtain a longitudinally stretched film. Next, on the A layer side of the longitudinally stretched film, inactive particles C are provided with a core-shell filler (core; cross-linked polystyrene, shell; polymethylmethacrylate) (average particle diameter; 30 nm, volume shape factor 0.45) manufactured by JRS Co., Ltd., SX 872
An aqueous coating solution (total solid content concentration 1.0%) having the same composition as in Example 1 was applied in the same manner as in Example 1 except that the content was changed to "1".

Subsequently, the mixture was supplied to a stenter and stretched 4.2 times in the transverse direction at 110 ° C. The obtained biaxially stretched film was heat set with hot air at 220 ° C. for 4 seconds to give a total thickness of 6.4.
A laminated biaxially oriented polyester film having a thickness of μm and a thickness of the thermoplastic resin layer B of 1.0 μm was obtained. The thickness of the thermoplastic resin layers A and B of this film was adjusted by the discharge amounts of the two extruders. Surface roughness WRa measured from the coating layer C side of the surface of the film, 1.7 nm, a Young's modulus of the film machine direction 5000N / mm ^2, was transverse 7000N / mm ^2. Table 1 shows the other properties of this laminated film and the properties of the ferromagnetic thin film deposition type magnetic tape using this film.

[Comparative Example 1] A laminated polyester film was obtained in the same manner as in Example 1 except that the solution viscosity of the cellulose contained in the coating layer C was changed as shown in Table 1. In the obtained film, the frequency of inactive particles C in the coating layer C falling off during film running was increased, and a large number of transfer to the opposite surface occurred. Therefore, when the film was made into a magnetic tape, sufficient electromagnetic conversion characteristics were obtained. I couldn't get it. Table 1 shows other characteristics and characteristics of the ferromagnetic thin film deposition type magnetic tape using this film.

[Comparative Example 2] A laminated polyester film was obtained in the same manner as in Example 1 except that the coating layer C was not applied. The resulting film has frequent peeling discharges during running,
Due to the rough surface of the polyester layer A, sufficient electromagnetic conversion characteristics could not be obtained when the tape was made into a magnetic tape.
Table 1 shows other characteristics and characteristics of the ferromagnetic thin film deposition type magnetic tape using this film.

[Comparative Example 3] A laminated polyester film was obtained in the same manner as in Example 1 except that the coating layer C did not contain cellulose. In the obtained film, the frequency of the inactive particles C in the coating layer C falling off during film running increases,
Since a large number of transfer to the opposite surface occurred and the surface of the polyester layer A was roughened by blocking, sufficient electromagnetic conversion characteristics could not be obtained when the magnetic tape was used. Table 1 shows other characteristics and characteristics of the ferromagnetic thin film deposition type magnetic tape using this film.

[Comparative Example 4] A laminated polyester film was obtained in the same manner as in Example 1 except that the type, the average particle size and the addition amount of the inert particles B contained in the polyester layer B were as shown in Table 1. It was The obtained film had a high degree of shape transfer to the surface opposite to the protrusion on the B layer side, and when used as a magnetic tape, sufficient electromagnetic conversion characteristics could not be obtained.
Table 1 shows other characteristics and characteristics of the ferromagnetic thin film deposition type magnetic tape using this film.

[0122]

[Table 1]

In Table 1, PEN represents polyethylene-2,6-naphthalate, and PET represents polyethylene terephthalate.

As is clear from Table 1, the laminated polyester film according to the present invention has a very flat one side and little transfer of the oligomer from the opposite side, exhibits excellent electromagnetic conversion characteristics, and is extremely windable. It is good. On the other hand, those which do not satisfy the requirements of the present invention cannot satisfy these characteristics at the same time.

[0125]

According to the present invention, a laminated polyester film having excellent blocking resistance, abrasion resistance, windability and processability, and particularly excellent electromagnetic conversion characteristics when used as a metal vapor deposition thin film type magnetic recording medium is obtained. Obtainable.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // C08L 67:00 C08L 67:00 (72) Inventor Hirofumi Murooka 3-37-19 Oyama, Sagamihara City, Kanagawa Prefecture F-Term inside Sagamihara Research Center of Teijin DuPont Films Co., Ltd. BA04 BA07 BA10A BA10C BA10D BA25 BA41 CA18 DE01A DE01B DE01C EH20 EH202 EH46 EH462 EJ05B EJ38 EJ382 GB41 JA06C JG06D JK09 JK14B JK14C JL01 YY00A YY00B YY00C 5D006 CB01 CB05 CB07 CB05 CB05 CB05CB07CB07

Claims (12)

[Claims] 1. A laminated film in which a polyester layer A, a polyester layer B and a coating layer C are laminated in this order, and the polyester layer B has an average particle diameter of 50 to 1000 nm.
Of the inert particles B of 0.001 to 1% by weight, the polyester layer A does not contain the inert particles or has an average particle size smaller than that of the inert particles contained in the polyester layer B. 1. The laminated polyester film containing 1 to 40% by weight of a cellulose compound having a viscosity of a 3% by weight aqueous solution at 20 ° C. in the range of 10 to 1000 mPa · s. 2. The coating layer C comprises, in addition to the cellulose compound, 40 to 89% by weight of (1) poly (meth) acrylic acid-polyester consisting of (meth) acrylic acid, polyvalent carboxylic acid and polyhydric alcohol, (2) Average particle size is 10
The laminated polyester film according to claim 1, which contains 1 to 20% by weight of 80 nm inactive particles C and 1 to 30% by weight of (3) a surfactant. 3. A poly (meth) acrylic acid-polycarboxylic acid component / (meth) acrylic acid component molar ratio in the polyester is 1/9 to 5/5, and the acrylic acid component is (A).
Alkyl methacrylate containing no epoxy groups (M _A) 65 to 97 mol% and (B) an epoxy group-containing (meth) acrylate (M _B) 3 to 35 laminated polyester film of claim 2 wherein comprising a mol%. 4. The inert particle B is at least one kind of particle selected from the group consisting of crosslinked silicone resin, crosslinked acrylic resin, crosslinked polyester, aluminum oxide, titanium dioxide, silicon dioxide, kaolin and clay. The laminated polyester film described. 5. The ten-point average roughness (WRzB) of the surface of the polyester layer B in contact with the coating layer C is 30 to 300 nm.
The laminated polyester film according to claim 1. 6. The laminated polyester film according to claim 1, wherein the surface roughness (WRaA) of the surface of the laminated polyester film on which the coating layer C is not laminated is in the range of 0.1 to 4 nm. 7. A coating layer D is laminated on the surface of the polyester layer A which is not in contact with the polyester layer B, and the coating layer D has an average particle diameter of 10 to 50 nm and a volume shape factor of 0.1 to 10.
The laminated polyester film according to claim 1, which contains 0.5 to 30% by weight of π / 6 inactive particles D. 8. The laminated polyester film according to claim 1, which has a thickness of 2 μm or more and less than 8 μm. 9. The laminated polyester film according to claim 1, wherein the polyester constituting the polyester layer A and the polyester layer B is polyethylene terephthalate or polyethylene-2,6-naphthalate. 10. A coating layer C of a laminated polyester film
The laminated polyester film according to any one of claims 1 to 9, which is used as a support for a magnetic recording medium by providing a magnetic layer on the surface on which the is not laminated. 11. A magnetic recording comprising the laminated polyester film according to any one of claims 1 to 9 and a magnetic layer provided on the surface on which the coating layer C is not laminated. Medium. 12. The magnetic recording medium according to claim 11, wherein the magnetic layer is a ferromagnetic metal thin film layer.