JPH07165943A - Biaxially oriented polyester film - Google Patents

Abstract

PURPOSE:To obtain a biaxially oriented polyester film having excellent scratch resistance and slittability and useful for packaging, etc., by including a specific amount of a specific double oxide in a film. CONSTITUTION:This biaxially oriented polyester film is produced by incorporating a polyester film composed of an aromatic dicarboxylic acid and a glycol with 100-20,000ppm of a double oxide consisting of two or more kinds of metals and oxygen and having an average primary particle diameter of 0.01-0.10mum, a specific surface area of 40-150m<2>/g and a chlorine-content of 0.001-0.5wt.%, e.g. a double oxide composed of two or more kinds of metals selected from Al, B, P, Si, Ge, Ti, Zr, W and Fe and oxygen.

Description

Detailed Description of the Invention

[0001]

2. Description of the Related Art Polyesters, particularly polyethylene terephthalate, have excellent physical and chemical properties, and biaxially oriented polyester films obtained by adding fine particles of inorganic compounds or organic compounds called lubricant particles to polyester are magnetic tapes. It is widely and commonly used as a film. Recently, there is an increasing demand for scratch resistance (scratch resistance) of base films for magnetic tapes. Scratch is caused by scratches on the part where the magnetic tape comes into contact (for example, scratches on the tape by a metal guide pin or a plastic cassette pin when dubbing with a high-speed sprinter) and abrasion powder generated in the running system in the tape deck. A scratch that can be applied. When a magnetic tape is manufactured using a base film having poor scratch resistance, the inside of the manufacturing apparatus is contaminated with powder generated by abrasion in the manufacturing process, and dropout occurs in the resulting magnetic tape. The above-mentioned improvement of scratch resistance is very important because it improves the quality of the magnetic tape.

As a method of improving abrasion resistance, inert fine particles having a certain hardness as a lubricant in a polyester film (for example, inert fine particles having a Mohs hardness of 6 or more) or alumina fine particles having a specific crystal type (for example, , Δ-alumina or γ-alumina) is known (for example, JP-A 1-311131, JP-A 3-6238, JP-A 3-6239, and Japanese Patent Publication No. 4-39). 40375). But,
In the above method, the scratch resistance of the film with respect to the plastic cassette pin is improved, but the scratch resistance with respect to the metal cassette pin during high-speed dubbing is not sufficient.
That is, it has been found that it is not important to use inert particles or alumina having the above-mentioned specific type of crystal form in order to increase the scratch resistance. As a method of improving this, a specific surface area of 40-100
A method using a composite oxide containing m ² of alumina / titanium oxide / silica as a component has been disclosed (Japanese Patent Laid-Open No. 5-17.
0943). It has been found that high dispersibility of particles is a key point for improving scratch resistance when it is attempted to impart a predetermined scratch resistance to a film using the above substances. Even if the surface area is sufficient, if the dispersibility of the particles is not sufficient, not only the predetermined scratch resistance cannot be obtained, but also secondary scratches due to coarse particles, that is, dropouts increase. In the base film for magnetic tape,
If the scratch resistance can be satisfied, the improvement of the quality of the tape is promoted and it is industrially very useful.

[0003]

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned conventional problems, and its purpose is to:
It is an object of the present invention to provide a biaxially oriented polyester film which has excellent scratch resistance and therefore has less scratches on the surface of the tape during a high-speed dubbing process.

[0004]

Means for Solving the Problems The inventors of the present invention have earnestly studied measures against the above problem from the viewpoint of a lubricant or a filler contained in the polyester film, and as a result, the present invention has been accomplished. The biaxially oriented polyester film of the present invention is a polyester film comprising an acid component mainly containing an aromatic dicarboxylic acid and at least one glycol component, and the polyester film has an average primary particle size of 0.01 μm or more and 0 μm or more. .1 μ or less, specific surface area 40-150 m ² / g, chlorine content of 0.001% or more and 0.05% or less, a composite oxide (A) composed of two or more different metal elements and oxygen elements. Is contained in an amount of 100 ppm or more and 20000 ppm or less.

In a preferred embodiment, the complex oxide (A) has a pH of 3.5 or more in a 10% aqueous dispersion system.
5 or less is shown. In a preferred embodiment, the composite oxide (A) is Al, B, P, Si, Ge, Ti, Z.
It contains at least two kinds of metal elements of r, W and Fe. In a preferred embodiment, the composite oxide (A)
Is a complex metal oxide (A) containing 20 mol% or more and 90 mol% or less of Al as a constituent component and 100 ppm or more and 20000 or more.
Contains below ppm. In a preferred embodiment, the composite oxide (A) is a composite oxide mainly composed of Al and Si, a composite oxide mainly composed of Al and Ti, Al and Z.
r composite oxide, Al and Fe composite oxide, Al, Si and Ti composite oxide, Al, Ti and Zr composite oxide, Al, Si and Zr composite oxide, Al 4. The biaxially oriented polyester film according to claim 3, wherein at least one kind is selected from a composite oxide composed of Si and Fe, and a composite oxide composed of Al, Ti and Fe. In a further preferred embodiment, the composite oxide (A) is Al
(Aluminum), Si (silicon) and O (oxygen) as main constituent elements, and is composed of a substantially amorphous compound, and the Al content (Al / (Al + Si) molar ratio) of the compound is 0.3. It is above 0.9 and below.

Next, the present invention will be described in detail. 2 of the present invention
The axially oriented polyester film is mainly composed of polyester. This polyester contains an acid component mainly containing an aromatic dicarboxylic acid and at least one glycol component, and 95 mol% or more of its constituent units are ethylene terephthalate units (consisting of terephthalic acid and ethylene glycol). It is preferable. Acid components other than terephthalic acid include isophthalic acid and p-β-
Oxyethoxybenzoic acid, 2,6-naphthalenedicarboxylic acid, 4,4-dicarboxyl phenyl, 4,4-dicarboxyl benzophenone, bis (4-carboxyl phenyl) ethane, adipic acid, sebacic acid, 5-sodium sulfoisophthalic acid , Cyclohexane-1,4
-Dicarboxylic acid components such as dicarboxylic acid; and oxycarboxylic acids such as p-oxybenzoic acid. As the glycol component other than ethylene glycol, propylene glycol, butanediol, neopentyl glycol, diethylene glycol, cyclohexanedimethanol, an ethylene oxide adduct of bisphenol A,
Polyethylene glycol, polypropylene glycol,
Examples thereof include polytetramethylene glycol. In addition, it may contain a small amount of a compound containing an amide bond, a urethane bond, an ether bond, a carbonate bond, or the like.

The complex oxide (A) used in the present invention is a covalent bond of AlCl ₃ , SiCl ₄ , Ti.
It is obtained by a method of burning chlorides such as Cl ₄ , ZrCl ₄ and FeCl ₄ in the presence of hydrogen and oxygen, or a combustion method. The structure of the composite oxide is considerably different from a mixture of oxides of each metal component contained in the composite oxide alone (for example, aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, iron oxide). That is, the complex oxide has a structure in which different elements are bonded by oxygen (for example, Al
-O-Si) as a main constituent component,
Although it depends on the abundance ratio of the elements, most of the amorphous oxides have extremely small structural characteristics (for example, crystal form) of the individual oxides. The complex oxide particles (A) used in the present invention further contain chlorine (ions) in an amount of 0.001 to 0.5.
Contains by weight%. As a result, even if the specific surface area of the composite oxide particles exceeds 100 m ² , the dispersibility of the composite oxide particles in the polyester will be good, and as a result, the abrasion resistance of the polyester film at high speed duplicator, Scratch resistance and abrasion resistance can be secured. When the chlorine ion content is less than 0.001% by weight, the dispersibility of the composite oxide particles in the glycol component or in the polyester during film formation is poor, and the resulting polyester film has abrasion resistance and scratch resistance. Etc. will be adversely affected.
If it exceeds 0.5% by weight, deterioration due to thermal decomposition of the polyester during the polymerization of the polyester and during film formation is not desirable. It is preferably 0.001% or more and 0.3% or less.

By appropriately selecting the starting material, the combustion conditions and the purification conditions, a composite oxide containing chlorine ions in a predetermined ratio can be obtained. The structure of the composite oxide thus obtained is quite different from that of the mixture of oxides of the respective metals contained in the composite oxide. That is, the composite oxide has a bond represented by a structure in which different elements are bonded with oxygen (for example, Al—O—Si) as a main constituent component. In the present invention, such a complex oxide is shown as, for example, Al ₂ O ₃ / SiO ₂ .
Although it depends on the ratio of the metal species and the metal components, most of the composite oxides of the present invention are amorphous oxides in which the structural characteristics (for example, crystal form) of oxides of each metal are extremely small.

As such a composite oxide, SiO₂
/ ZrO₂, SiO₂/ Fe₂O₃, TiO₂/ Fe₂
O₃, Al₂O₃/ SiO₂, Al₂O₃/ TiO₂,
Al ₂O₃/ ZrO₂, Al₂O₃/ Fe₂O₃Etc. 2
Original composite oxide; Al₂O₃/ SiO₂/ Fe₂O₃, A
l₂O₃/ SiO₂/ TiO₂, Al₂O₃/ TiO ₂
/ ZrO₂, Al₂O₃/ SiO₂/ ZrO2 etc. ternary
Complex oxides; and more complex multi-component oxides
You can Al having Al among the above as one constituent metal
₂O₃/ SiO₂, Al₂O₃/ TiO₂, Al₂O₃
/ ZrO₂Binary oxides such as Al, and Al₂O₃/ S
iO₂/ TiO₂, Al₂O₃/ TiO ₂/ ZrO₂,
Al₂O₃/ SiO₂/ ZrO₂ Ternary complex oxides such as
Are preferable from the viewpoint of the effect of improving scratch resistance, and among them, binary type
Al₂O₃/ SiO₂Has a remarkable effect of improving scratch resistance
Since it is large, it is particularly preferable. Furthermore, the Al content (A
1 / (Al + Si) molar ratio) is 0.3 or more and 0.9 or less
Certain amorphous complex oxides are preferred. Two-dimensional system is three-dimensional
From the above system, a composite oxide having a uniform primary particle size can be obtained,
It is preferable in terms of improving scratch resistance and abrasion resistance.

The "amorphous" means the X of the composite oxide particles.
In line diffraction, a broad peak area (Pam) appearing in the range of 2θ = 10 degrees to 45 degrees and a sharp peak area (Pc) appearing in the range of 2θ = 65 degrees to 70 degrees (Pc)
r) and the area ratio obtained from the following equation (see FIG. 1), and when the value is 0.7 or more,
It is said to be "amorphous". When calculating the above area,
As shown in FIG. 1, a base line is set for each peak, and areas between the peak and the base line are Pam and Pcr, respectively. Amorphousness = Pam / (Pcr + Pam). The composite oxide particles may be particles of any shape. Further, in the above-mentioned composite oxide, a single oxide of the composite oxide-constituting metal such as Al ₂ O ₃ , SiO ₂ , B ₂ O ₃ , TiO ₂ , Zr is used as a by-product in the production.
The inclusion of O ₂ , WO ₃ , Fe ₂ O ₃ , etc. is not a problem as long as their average primary particle diameter is less than 0.1 μ. These crystal forms are not particularly limited.

Composite oxide particles (A) used in the present invention
Has an average primary particle diameter of 0.01 to 0.1 μm, preferably 0.01 to 0.05 μm, and most preferably 0.1.
It is 01 to 0.03 μm. When the average primary particle diameter of the composite oxide particles (A) is 0.1 μm or more, the diameter of the secondary aggregate in the polyester becomes large, which causes dropout, which is not preferable. Furthermore, it becomes difficult to cut the obtained film (slitting property deteriorates),
(Hereafter, the ease of cutting is referred to as "slit property"). The average primary particle diameter of the composite oxide particles (A) is 0.0
When it is less than 1 μm, the aggregation of the composite oxide particles becomes severe during the polyester polymerization, and coarse projections occur in the obtained film. When such a film is used as a magnetic tape, the surface of the tape may be scratched due to coarse protrusions,
Or dropout will occur.

The above-mentioned average primary particle diameter is the average particle diameter of the material in the form of the smallest unit which is not aggregated, and does not mean the particle diameter of the secondary aggregate formed by the aggregation of the particles. Absent. The average particle size of the primary particles is the arithmetic mean of the particle diameters observed by an electron microscope. From the viewpoint of scratch resistance, the particle size distribution of the composite oxide particles (A) is preferably close to monodisperse. The composite oxide particles (A) used in the present invention are substantially non-porous, and have a specific surface area of 40 m ² / g or more and 150 m ² / g or less. From the viewpoint of imparting an effect of scratch resistance and suppressing secondary scratches, 101 m ² / g or more and 130 m ² / g or less are particularly preferable.

The content of the composite oxide particles (A) in the biaxially oriented polyester film of the present invention is 100 to 20.
It is necessary to be 000 ppm, preferably 10
It is from 00 to 5000 ppm. When the content of the composite oxide particles (A) is less than 100 ppm, the obtained polyester film does not have sufficient scratch resistance.
The content of the composite oxide particles (A) is 20000 ppm
When it exceeds, the ratio of the composite oxide particles contained in the obtained film is dropped off when the film is run, and the dropped particles have a higher hardness than the polyester film, so that the film surface is damaged. Furthermore, the heat resistance of the polyester film is also reduced. When the obtained film is laminated and used, the above content means the content in the outermost layer and does not mean the content in the entire multilayer.

The surface of the composite oxide particles (A) may be modified with various surface treating agents. As the surface treatment agent used for the purpose of suppressing aggregation as much as possible or for improving the affinity with the glycol component or polyester, phosphoric acid and its derivatives (for example, phosphoric acid ester, alkali metal salt of phosphoric acid, phosphorus Acid ammonium salt), polyacrylic acid ammonium salt, polymethacrylic acid ammonium salt, alkali metal hydroxide, silane coupling agent, titanium coupling agent and the like, and sodium hydroxide is particularly preferable. The surface treatment agent is generally used in an amount of 5% by weight or less based on the composite oxide particles (A).

In the biaxially oriented polyester film of the present invention, in addition to the composite oxide particles (A), calcium carbonate (CaCO ₃ ), barium sulfate (BaSO ₄ ), calcium fluoride (CaF ₂ ), talc, kaolin. Inert inorganic compound particles made of titanium oxide, silicon oxide (SiO ₂ ), alumina or the like; organic particles made of crosslinked polystyrene, crosslinked polymethacrylic acid ester, crosslinked polyacrylic acid ester or the like may be contained as a lubricant. . From the viewpoint of mobility, silicon oxide (silicon oxide having a spherical particle shape),
Alternatively, particles made of calcium carbonate (CaCO ₃ ) are preferable. Kaolin is particularly preferable from the viewpoint of scratch resistance. For further improvement of the sharpness, it is preferable to use calcium carbonate or silica having a particle size of 0.4 μ or more. Further, in order to further improve the scratch resistance, it is preferable to use spherical organic particles having a relatively low hardness, that is, a low crosslink density.

The calcium carbonate particles have three crystals of calcite classified as trigonal or hexagonal, aragonite classified as orthorhombic, and vaterite classified as hexagonal or pseudo-hexagonal depending on their crystal structure. Although it is classified into types, any crystal type may be used, and the shape thereof can be arbitrarily selected such as a go-stone shape, a rugby ball shape, a plate shape, a continuous spherical shape, a cubic shape, a spindle shape, a columnar shape, a needle shape, a spherical shape, and an oval shape. . From the viewpoint of improving scratch resistance and abrasion resistance during high-speed running, gostone-like or plate-like calcium carbonate is particularly preferable. The kaolin particles may be of any type regardless of natural kaolin, synthetic kaolin, calcinability, and non-sinterability, and the shape thereof may be arbitrarily selected such as plate shape, columnar shape, spherical shape, spindle shape, and egg shape.

When the above-mentioned inert inorganic compound particles and organic particles are contained in the biaxially oriented polyester film of the present invention, the total content of these particles is 5
It is preferably from 00 to 10000 ppm, more preferably from 1500 to 7000 ppm. Content of the above-mentioned inert inorganic compound particles and organic particles is 500 ppm
When it is less than 1, the obtained polyester film does not have sufficient slipperiness. When the content of the above-mentioned inert inorganic compound particles and organic particles exceeds 10000 ppm, coarse protrusions are formed on the surface of the film by the inert inorganic compound, and the abrasion resistance of the film decreases. When the obtained film is laminated and used, the above content means the content in the outermost layer and does not mean the content in the entire multilayer.

For the purpose of further improving scratch resistance, Al ₂ O ₃ and Si having an average primary particle diameter of 0.1 μm or less are used.
It is also possible to add at least one kind of ultrafine particles of O ₂ , TiO ₂ , ZrO ₂ , Fe ₂ O _3, etc. into the biaxially oriented polyester film of the present invention. Examples of such alumina include crystalline alumina hydrates such as gibbsite, bayerite, nordstrandite, boehmite, diaspore, and todite; amorphous alumina hydrates such as amorphous gel, boehmite gel, and bayerite gel; And ρ, η, γ, χ, κ, δ, θ type intermediate activated alumina or α type alumina, and among them, δ type or γ type intermediate activated alumina is preferable.

The content of these ultrafine particles is preferably 20000 ppm or less in total with the composite oxide particles of the present invention. If it exceeds 20000ppm,
The composite oxide particles contained in the obtained film often fall off when the film is run, and the dropped particles damage the film surface because they have higher hardness than the polyester film. Furthermore, the heat resistance of the polyester film is also reduced. When the obtained film is laminated and used, the above content means the content in the outermost layer and does not mean the content in the entire multilayer.

In the production of the polyester of the present invention, the dispersibility of lubricants (that is, composite oxide particles, inert inorganic compound particles, and organic particles) is improved, and the electrostatic adhesion of the resulting film is improved. For at least one of alkali metal hydroxides or salts such as sodium hydroxide and lithium hydroxide, and alkaline earth metal salts such as magnesium acetate and calcium acetate; phosphoric acid;
It is possible to add a phosphoric acid alkyl ester or a derivative thereof. In this case, the molar ratio of the additive represented by the following formula is preferably 0.4 to 1.0. Above all, a combination system of sodium hydroxide, magnesium acetate and phosphoric acid or trimethyl phosphate is most preferable from the viewpoint of suppressing aggregation of the composite oxide.

[0021]

[Equation 1]

When the above molar ratio is less than 0.4 or more than 1.0, the added composite oxide particles and the particles of the inert inorganic compound such as calcium carbonate tend to agglomerate, resulting in coarse particles in the polyester. Particles are generated, and thus the magnetic tape using such polyester is apt to drop out. The composite oxide particles (A)
The method of mixing with the polyester is a method of adding the composite oxide particles to the polyester polycondensation reaction system to complete polycondensation, or a method of adding the composite oxide particles to the molten polyester and kneading. , Either method can be adopted. Usually, the former method is preferable from the viewpoint of dispersibility of the composite oxide particles in the polyester. in this case,
The composite oxide particles are usually added to the reaction system as a slurry in addition to the glycol component. The timing of addition depends on the type of composite oxide particles used, the particle size, the chlorine ion concentration, the slurry concentration when the particles are made into a slurry, the temperature of the slurry, and the like. Usually, the addition time is preferably before the start of the polycondensation reaction. Generally, the surface treatment agent is added to a slurry composed of the composite oxide particles (A) and a glycol component at the time of polyester preparation, whereby the dispersibility of the particles in the obtained polyester is improved. It will increase even more. At this time, the dispersibility of the particles in the polyester is further improved by heating the slurry to the boiling point of the glycol component.

The method for producing the biaxially oriented polyester film of the present invention may be any method and is not particularly limited. For example, there are the following production methods. First, a polyester film prepared by adding the above-mentioned inactive inorganic or organic compound particles to the composite oxide particles and, if necessary, for forming protrusions on the film surface, by a conventional method, Biaxially stretched in the direction. The stretching order may be any of vertical and horizontal, horizontal and vertical, and simultaneous biaxial methods. Alternatively, three or more stages of stretching may be performed by appropriately combining transverse stretching, longitudinal stretching and simultaneous biaxial stretching. After biaxially stretching the polyester film, heat treatment is usually performed with a tenter. Heat treatment at 190 ~ 230 ℃ 2
It is preferable to carry out for 10 seconds, and it is preferable to carry out re-stretching of 2 to 30% in the transverse direction or both longitudinal and transverse directions simultaneously with the heat treatment. After the heat treatment, relaxation treatment may be performed in the horizontal direction and the vertical direction. Lateral relaxation is 130-170 ℃
It is preferable to carry out in a tenter. The vertical relaxation is
It is preferably carried out on a heating roll at a temperature of 80 to 150 ° C. A multilayer film obtained by using at least one layer obtained by the present invention as the outermost layer is also useful.

(Function) The biaxially oriented polyester film of the present invention has an average primary particle diameter of 0.01 μ to 0.05 μ.
Below, specific surface area is 40-150 m ² / g, chlorine content is 0.001% or more and 0.5% or less, 10% pH in aqueous solution
Contains 3.5 to 5.5 of the composite oxide particles having excellent dispersibility, and therefore has excellent affinity with polyester and does not impair the slit property. Furthermore, when a magnetic tape was prepared using this as a base film, the scratch resistance to plastic cassette pins of this tape, and the scratch resistance to metal guide pins in a high-speed duplicator running system were significantly improved. It

(Examples) Next, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. The methods for measuring the physical properties and characteristics of the films obtained in Examples and Comparative Examples are shown below. (1) Average Primary Particle Diameter of Composite Oxide Particles and Other Inorganic Compound Particles (Lubricants) Observing the composite oxide particles of the present invention at a magnification of 100,000 using a transmission electron microscope manufactured by Hitachi, Ltd. Then, the diameter of the particles was measured from the photograph. The average of 500 measured values of these particles was calculated and taken as the average primary particle diameter.

(2) Specific Surface Area of Composite Oxide Particles The specific surface area of each composite oxide was measured by the BET method described in JIS K-1474.

(3) Chlorine content in complex oxide particles A predetermined amount of complex oxide particles was immersed in pure water for one day at room temperature and then filtered with a 0.1 μ filter. The Cl ion in the obtained filtrate was quantified by ion chromatography (Yokogawa IC-100 manufactured by Hokushin Electric Co., Ltd.).

(4) pH Measurement of Composite Oxide Particles 10 g of the composite oxide particles were added to 100 ml of pure water at 25 ° C., and after stirring for 10 minutes, a pH meter (HORIBA pH meter F-) adjusted with a standard solution was added. The pH of the dispersion was measured in 14).

(5) Amorphousness of Al / Si-based composite oxide particles Amorphousness of the composite oxide particles was determined by a reflection method using a high intensity X-ray diffractometer manufactured by Rigaku Denki Co., Ltd. Measurement conditions: Cu-Kα ray subjected to nickel filter Measurement angle 2θ = 10 to 90 degrees 45 kV, 150 mA Scan speed = 2 degrees / min Amorphous degree of composite oxide particles containing SiO ₂ / Al ₂ O ₃ as a component In X-ray diffraction, a broad peak area (Pam) appearing in the range of 2θ = 10 degrees to 45 degrees and 2
It was calculated by the following formula from the area (Pcr) of a sharp peak appearing in the range of θ = 65 degrees to 70 degrees (see FIG. 1). To calculate the area, a baseline was set for each peak as shown in FIG. 1, and the areas between the peak and the baseline were defined as Pam and Pcr, respectively. Amorphousness = Pam / (Pcr + Pam).

(6) Average Surface Roughness of Film Using a Surfcom 300A surface roughness meter (manufactured by Tokyo Seimitsu Co., Ltd.), needle diameter 1 μm, weight 0.07 g, measurement reference length 0.8 m.
The center line average roughness (Ra: μm) was measured when the film surface was measured under conditions of m and cutoff of 0.08 mm.

(7) Sliding property of film (friction coefficient) According to ASTM D-1894-63, the static friction coefficient between two films was measured under the environmental conditions of 23 ° C. and 65 RH% using a thread type strip tester. It was measured.

(8) Slitting The biaxially stretched film was slit into a 1/2 inch width using a slitter. At this time, the slits were observed and ranked as follows according to how much whiskers and powder were generated. 1 ... No whiskers or powder generation 2 ... Small whiskers or powder generation 3 ... Many whiskers or powder generation

(9) Scratch Resistance of Film to Metal Pins A polyester film cut into a width of 10 mm is Fe-C.
The r-made pin is made to travel while rubbing once at a tension of 100 g, a winding angle of 45 degrees, and a running speed of 300 m / min. Then
The amount of scratches was visually determined on the actual micrograph and ranked as follows. 1 ... No scratches are recognized 2 ... Slight scratches are recognized but extremely small amount 3 ... Small amount of scratches is recognized 4 ... Large amount of scratches are recognized

(10) Scratch resistance of film against plastic pin A polyester film cut into a width of 10 mm is rubbed once with a plastic pin at a tension of 100 g, a winding angle of 90 degrees, and a running speed of 150 m / min. Next, aluminum was vapor-deposited on the friction surface, and the amount of scratches on the aluminum vapor-deposited surface was visually determined by a micrograph of the actual state, and ranked as follows. 1 ... No scratches are observed 2 ... Slight scratches are recognized but extremely small amount 3 ... Small amount of scratches is recognized 4 ... Large amount of scratches are recognized If the films are ranks 1 and 2, there is no problem in practical use.

(Example 1) <Preparation of polyester composition a> AlCl ₃ and Si
An average primary particle diameter of 0.02 μm, a specific surface area of 90 m ² / g, a Cl content of 0.3% by weight, and an amorphousness of 0.96 by a method of burning Cl ₄ as a starting material in a gas phase of hydrogen and oxygen. , Al / (Al + S which becomes pH 4.0 in the aqueous solution
i) Molar ratio = 0.58 [Hereinafter, in Table 1, "Al /
(Al + Si) ”and the corresponding molar ratio are“ A
/ (A + B) ”] was obtained.
In Table 1, one of the metals or silicon contained in the binary composite oxide is represented by "A" and the other is represented by "B".
It is represented by. The obtained composite oxide particles were wet-ground in ethylene glycol to obtain a 20% by weight slurry having an average particle diameter of 0.06 μm. On the other hand, 100 parts by weight of terephthalic acid, 70.7 parts by weight of ethylene glycol, 0.0697 parts by weight of antimony trioxide, 0.271 of triethylamine.
Parts by weight and 0.0931 parts by weight of magnesium acetate were added, and esterification was carried out at 250 ° C. and a pressure of 2.5 kg / cm ² . After completion of the esterification, 0.0327 parts by weight of trimethyl phosphate was added to this solution under normal pressure to
Stirring was carried out at 0 ° C. After 30 minutes, the concentration of the composite oxide was 2% by weight with respect to the produced polyester,
A predetermined amount of the slurry was added and the mixture was further stirred for 30 minutes. After that, polycondensation reaction is performed under vacuum, and the intrinsic viscosity η =
A polyethylene terephthalate composition of 0.60 was obtained.
(Polyester composition a).

<Preparation of Polyester Composition b> In the production of the above polyester composition a, the same procedure is used except that calcium carbonate (inorganic compound particles) having an average particle diameter of 0.45 μm is added instead of the above composite oxide particles. Polymerization is carried out, calcium carbonate concentration 2%, intrinsic viscosity η = 0.62
A polyethylene terephthalate composition of was obtained. (Polyester composition b).

<Preparation of Polyester Composition c> In the production of the above polyester composition a, polymerization is performed in the same manner except that kaolin (inorganic compound particles) having an average particle diameter of 0.4 μm is added instead of the above composite oxide particles. Then, a polyethylene terephthalate composition having a kaolin concentration of 2% and an intrinsic viscosity η = 0.61 was obtained. (Polyester composition c).

<Preparation of Polyester Composition d> In the production of the polyester composition a, the intrinsic viscosity η = 0.6 is obtained in the same manner except that the composite oxide particles are not included.
A polyethylene terephthalate composition of No. 2 was obtained. (Polyester composition d).

The resulting polyester composition a, polyester composition b, polyester composition c and polyester composition d were mixed in a predetermined weight ratio, and the A / (A + B) molar ratio of the composite oxide particles to the mixture and the The concentrations of calcium carbonate and kaolin particles are shown in Table 1.
The concentration was set to the value shown in. The mixture was dried, melted at 280 ° C., and cast on a cooling drum at 30 ° C. to obtain an unstretched film having a thickness of 220 μm. Then, this film was heated with a roll heated to 75 ° C. and an infrared heater having a surface temperature of 600 ° C. (installed at a position 20 mm away from the film), and then, in the longitudinal direction between the low speed roll and the high speed roll. It was stretched 3 times. Further, this film was stretched 4.4 times in the transverse direction at 100 ° C. in a tenter. In the tenter, the transverse stretching was followed by heat treatment, re-transverse stretching, and relaxation in the transverse direction. Next, the film is brought into contact with a roll heated to 120 ° C., and the tension between the heating roll and the rolls before and after the film is controlled to perform relaxation in the longitudinal direction,
A biaxially oriented polyester film having a thickness of 15 μm was obtained.
The characteristics of the film thus obtained are shown in Table 1.
Similarly, Table 1 also shows Examples 2 to 6 and Comparative Examples 1 to 3 described later.

(Examples 2 to 7) Composite oxide particles contained in the polyester composition a and the polyester composition b
In the same manner as in Example 1 except that the type of the inorganic compound particles contained in, the average particle diameter of each, and the content of each are shown in Table 1 and the film forming conditions were changed as appropriate. An oriented polyester film was obtained.

(Comparative Examples 1 to 3) Polyester composition a does not contain complex oxide particles, and polyester composition b
In the same manner as in Example 1 except that the type of the inorganic compound particles contained in, the average particle diameter of each, and the content of each are shown in Table 1 and the film forming conditions were changed as appropriate. An oriented polyester film was obtained.

[0042]

As described above, the present invention is excellent in scratch resistance and slitting property, and is useful in industrial fields other than magnetic recording media and packaging fields.

[0043]

[Table 1]

[Brief description of drawings]

FIG. 1 shows an example of the result of X-ray diffraction of a composite oxide.

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location // B29K 67:00 505: 00 B29L 7:00

Claims (7)

[Claims] 1. A polyester film comprising an acid component mainly containing an aromatic dicarboxylic acid and at least one glycol component, wherein the polyester film has an average primary particle diameter of 0.01 μ or more and 0.10 μ or less, A composite oxide (A) composed of two or more different metal elements and oxygen elements having a surface area of 40-150 m ² / g and a chlorine content of 0.001% by weight or more and 0.5% by weight or less is 100
A biaxially oriented polyester film, characterized in that it is contained in the range of ppm to 20000 ppm. 2. The composite oxide (A) according to claim 1 is 10
The biaxially oriented polyester film according to claim 1, which has a pH of 3.5 or more and 5.5 or less in a weight% aqueous dispersion system. 3. The biaxially oriented polyester film according to claim 1, wherein the average primary particle size of the composite oxide (A) according to claim 1 is 0.01 μ or more and 0.05 μ or less. 4. The composite oxide (A) according to claim 1 is A
The biaxially oriented polyester film according to any one of claims 1 to 3, comprising at least two kinds of metal elements of 1, B, P, Si, Ge, Ti, Zr, W and Fe. 5. The composite oxide (A) according to any one of claims 1 to 4, which contains 20 mol% or more and 90 mol% or less of the composite metal oxide (A) containing A1 as a constituent component. The biaxially oriented polyester film according to any one of claims 1 to 4. 6. The complex oxide (A) according to claim 4 or 5, wherein the complex oxide mainly comprises Al and Si,
l and Ti composite oxide, Al and Zr composite oxide, Al and Fe composite oxide, Al, Si and Ti composite oxide, Al and Ti and Zr composite oxide, Al And at least one selected from the group consisting of a complex oxide consisting of Si and Zr, a complex oxide consisting of Al, Si and Fe, and a complex oxide consisting of Al, Ti and Fe. Oriented polyester film. 7. The composite oxide particles (A) according to claim 4 to claim 6, wherein Al (aluminum), Si (silicon)
And a substantially amorphous compound containing O (oxygen) as a main constituent element, and the Al content (Al / (A
The biaxially oriented polyester film according to claim 4, wherein the (l + Si) molar ratio is 0.3 or more and 0.9 or less.