JPH0625514A - Thermoplastic polyester composition and film - Google Patents

Abstract

PURPOSE:To provide a thermoplastic polyester composition comprising a polyester containing organic polymer fine particles extremely fine in their particle diameters and inorganic particles having a specific particle diameter, and giving films excellent in flatness, lubricity and wear resistance. CONSTITUTION:This thermoplastic polyester composition comprises (A) a thermoplastic polyester preferably consisting mainly of a polyethylene terephthalate, (B) organic polymer fine particles (preferably, styrene/ethylvinylbenzene/ divinylbenzene copolymer, etc.) having a particle diameter of 0.002-0.1mum, preferably 0.02-0.08mum, more preferably 0.002-0.07mum, preferably the heat-resistant organic polymer fine particles having a thermal decomposition temperature of >=350 deg.C, in an amount of 0.01-10wt.% based on the component A, and (C) inorganic particles (preferably silicon dioxide or calcium carbonate) having a particle diameter of 0.002-5mum in a B/C weight ratio of 1/(0.001-10). The biaxially oriented (laminated) polyester film comprising this composition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic polyester composition containing organic polymer fine particles having extremely fine particle diameters and inorganic particles, and more specifically to flatness when formed into a molded article, The present invention relates to a thermoplastic polyester composition and a film having excellent abrasion resistance.

[0002]

2. Description of the Related Art Generally, thermoplastic polyesters such as polyethylene terephthalate have excellent mechanical properties and chemical properties and are widely used as molded articles such as films and fibers. In particular, the polyethylene terephthalate film is excellent in flatness, mechanical strength and dimensional stability and is suitable as a base film for a magnetic recording medium.
On the other hand, with the recent development of magnetic recording media, the properties required for the base film have become increasingly severe.

For example, when high density recording such as a video tape is required, the surface of the base film is required to be flatter. However, when the surface becomes flat, surface friction,
Abrasion increases, scratches are generated on the film surface, abrasion powder is generated, and many other problems occur.

When the wear resistance of a molded product, for example, a film for magnetic tape is low, abrasion powder of the film is apt to be generated during the manufacturing process of the magnetic tape, resulting in coating omission in the process of applying the magnetic layer, resulting in , Cause magnetic recording dropout. In addition, when using a magnetic tape, in most cases, it is run while contacting with a recording / reproducing device, etc., so abrasion powder generated at the time of contact adheres to the magnetic material, and a dropout (drop / drop) of magnetic recording occurs at the time of recording / reproducing. Out).

That is, the magnetic tape film is required to have slipperiness and abrasion resistance both during the magnetic tape manufacturing process and when used as a magnetic tape.

As a method for improving flatness and wear resistance, a so-called back coating method, in which an appropriate coating is provided on the surface opposite to the magnetic layer, is effective, but it is extremely expensive and has various characteristics. There are problems, and it is not a practically effective method.

Further, in JP-A-3-221556, crosslinked polymer particles (c) having an average particle size of 0.01 μm or more and less than 0.1 μm and crosslinked polymer particles (d) having an average particle size of 0.1 to 5 μm are used. Although it is contained to improve slipperiness and wear resistance, the effect is not sufficient, and the effect is small especially when the vehicle is run at high speed.

[0008]

The object of the present invention is to provide an organic polymer fine particle having an extremely small particle diameter and an inorganic particle having a specific particle diameter in a polyester to obtain excellent flatness, slipperiness, and It is intended to provide a polyester composition and a film having abrasion resistance.

[0009]

The above-mentioned object of the present invention is achieved by the following constitution. (1) An organic polymer fine particle having a particle diameter of 0.002 μm or more and less than 0.10 μm is added to the polyester in an amount of 0.01
Inorganic particles having a particle size of 10% by weight and 0.002 μm or more and less than 5 μm are used in a weight ratio of 0.00 with respect to the organic polymer particles.
1 to 10 are laminated on at least one surface of the thermoplastic polyester composition, (2) the biaxially oriented polyester film comprising the polyester composition of (1), and (3) the polyester composition of (1) A biaxially oriented laminated polyester film characterized in that

The thermoplastic polyester in the present invention is produced by a polycondensation reaction using a bifunctional component such as an aromatic dicarboxylic acid or its dialkyl ester and a glycol component as raw materials, and is mainly composed of polyethylene terephthalate. Is preferred. The polyester may be a homopolyester or a copolyester, and examples of the copolymerization include adipic acid, sebacic acid, phthalic acid, isophthalic acid, naphthalene-2,6-
Dicarboxylic acid, dicarboxylic acid component such as 5-sodium sulfoisophthalic acid, polyvalent carboxylic acid component such as trimellitic acid and pyromellitic acid, and tetramethylene glycol, hexamethylene glycol, diethylene glycol, propylene glycol, neopentyl glycol,
Examples include diol components such as polyoxyalkylene glycol, p-xylylene glycol, 1,4-cyclohexanedimethanol, and 5-sodium sulforesorcin.

In the present invention, when the particle size of the organic polymer fine particles is 0.002 μm or more and less than 0.10 μm, abrasion resistance is good, which is desirable. It is preferably 0.002 μm or more and less than 0.08 μm, and more preferably 0.002 μm or more and less than 0.07 μm.

The organic polymer fine particles in the present invention include, for example, polystyrene or crosslinked polystyrene particles, styrene-acrylic and acrylic crosslinked particles, styrene.
Examples of the particles include vinyl particles such as methacrylic and methacrylic crosslinked particles, particles of benzoguanamine formaldehyde, silicone, polytetrafluoroethylene, polyphenyl ester, phenol resin, etc. Any particle may be used as long as it is an organic polymer fine particle in which at least a part of the formed portion is insoluble in polyester. Preferably,
Generally, a copolymer of a monovinyl compound (A) having only one aliphatic unsaturated bond in the molecule and a compound (B) having two or more aliphatic unsaturated bonds in the molecule as a crosslinking agent is Can be mentioned.

Examples of the compound (A) in the above copolymer include aromatic monovinyl compounds such as styrene, α-methylstyrene, fluorostyrene, vinylbilin and ethylvinylbenzene, and vinyl cyanide compounds such as acrylonitrile and methacrylonitrile. Acrylic acid such as, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, octyl acrylate, dodecyl acrylate, hexadecyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, glycidyl acrylate, N, N'-dimethylaminoethyl acrylate Ester monomer, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate,
Butyl methacrylate, sec-butyl methacrylate, allyl methacrylate, phenyl methacrylate,
Methacrylic acid ester monomers such as benzyl methacrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate, N, N'-dimethylaminoethyl methacrylate,
Mono- or dicarboxylic acids such as acrylic acid, methacrylic acid, maleic acid and itaconic acid, and acid anhydrides of dicarboxylic acids, and amide monomers such as acrylamide and methacrylamide may be used.

Examples of the compound (B) include divinylbenzene compound, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate,
Alternatively, ethylene glycol diacrylate, ethylene glycol dimethacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, 1,3-butylene glycol diacrylate,
Mention may be made of polyvalent acrylates and methacrylates such as 1,3-butylene glycol dimethacrylate, trimethylolpropane triacrylate and trimethylolpropane trimethacrylate. Of the compound (B),
From the viewpoint of controlling the particle size, it is preferable to use divinylbenzene, ethylene glycol dimethacrylate or trimethylolpropane trimethacrylate. These compounds (A) and (B) can also be used as a copolymer by using two or more kinds.

Preferred examples of the composition of the organic polymer fine particles of the present invention include butyl acrylate-divinylbenzene copolymer, ethylvinylbenzene-divinylbenzene copolymer, 2-ethylhexyl acrylate-
Examples thereof include crosslinked polymer fine particles such as divinylbenzene copolymer and 2-ethylhexyl acrylate-ethylene glycol dimethacrylate copolymer. In addition, butyl acrylate-ethyl vinyl benzene-divinyl benzene copolymer, styrene-ethyl vinyl benzene-divinyl benzene copolymer, 2-ethylhexyl acrylate-
The fine particles may be produced by a three-component system such as ethylene glycol dimethacrylate-divinylbenzene copolymer, or a multi-component system of more than three components.

In the production of the organic polymer fine particles used in the present invention, components other than the compounds (A) and (B) may be added to control the particle size and improve heat resistance and dispersibility. Therefore, coating with a slight amount of an inorganic substance, surface treatment for improving affinity, and the like may be performed. In addition, for example, diethylbenzene which is an impurity of commercially available divinylbenzene may be contained.

The organic fine particles used in the present invention may be used as a mixture of two or more kinds as long as the present invention satisfies the particle diameter and the total addition amount of the present invention.

The term "degree of crosslinking" as used herein means the monovinyl compound (A) having only one aliphatic unsaturated bond in the molecule forming the organic polymer fine particles, and 2 in the molecule as a crosslinking agent.
It means the weight% of the component (B) in the compound (B) having one or more aliphatic unsaturated bonds, and is specifically represented by the following formula. Crosslinking degree (%) = B / (A + B) × 100

Regarding the heat resistance of the organic polymer fine particles of the present invention, particles having a heat decomposition temperature of 350 ° C. or higher by a thermobalance are preferable, more preferably 360 ° C. or higher, and particularly preferably 360 ° C. or higher. It is preferably 380 ° C. or higher. If the temperature is lower than 350 ° C, particles tend to aggregate during production of the polyester composition, during melt molding, or during recovery and reuse of the molded product, so that the surface uniformity and wear resistance of the molded product tend to be alienated. In order to have such heat resistance, it is necessary to highly crosslink with the crosslinking agent of the compound (B). The type of cross-linking agent is not particularly limited, but divinylbenzene is preferable, and pure divinylbenzene is preferably 5% by weight with respect to the entire monomers forming the organic polymer.
More preferably, it is 8% by weight or more.

As the organic polymer fine particles used in the present invention, those obtained by a known production method can be used. As a known production method, there is a method such as the following by emulsion polymerization. (1) Soap-free polymerization method, that is, a method of using no emulsifier or using an extremely small amount of emulsifier. (2) A seed polymerization method in which polymer particles are added to the polymerization system prior to emulsion polymerization and emulsion polymerization is performed. (3) A core-shell polymerization method in which a part of the monomer components is emulsion-polymerized and the remaining monomers are polymerized in the polymerization system. (4) JP-A-54-97582 and JP-A-5-97582
A polymerization method using Eugelstat or the like disclosed in JP-A-4-126288. (5) A polymerization method which does not use a swelling aid in the method of (4). Further, in order to control the particle size, the component concentration, temperature, stirring state, etc. may be changed at any stage of the polymerization.

In the present invention, the organic polymer fine particles may have a functional group. The kind of such a functional group is not particularly limited, and examples thereof include a metal salt of a carboxyl group, a hydroxyl group, a sulfonic acid group, an ester group, and a carboxyl group.

The method of introducing the functional group is not particularly limited, but from the viewpoint of the heat resistance of the particle, it is preferable to once produce a particle that becomes a highly crosslinked matrix and introduce the functional group on the surface of the matrix particle. Particularly, from the viewpoint of dispersibility of particles, it is desirable to introduce a functional group which is preferably non-reactive with polyester. For example, when introducing a sodium salt of a carboxyl group, a styrene-divinylbenzene copolymer is used as a base particle to produce particles highly crosslinked with divinylbenzene, and then a carboxyl group is introduced onto the particle surface with methacrylic acid. . The functional group of -COONa is introduced on the surface of the particles by making the inside of the particle production system alkaline. Further, the above-mentioned organic polymer fine particle slurry, in order to improve the particle dispersibility in the slurry, an anionic system,
A cationic or nonionic surfactant may be added. The particles may be added at any time during the production of the particles, or may be added to the slurry after the production of the particles. The particle size of the inorganic particles in the present invention is 0.002 μm or more and less than 5 μm. It is preferably 0.004 μm or more and less than 4 μm, and more preferably 0.005 μm or more and less than 3 μm because the running property and wear resistance are improved.

The type of the inorganic particles used in the present invention is not particularly limited, but for example, silicon oxide, kaolin, titanium oxide, aluminum oxide, calcium carbonate, aluminum silicate, talc, barium sulfate, sodium phosphate, monolithium phosphate. Examples thereof include trilithium phosphate, calcium phosphate, carbon black, graphite, zirconia, magnesium carbonate, and tungsten oxide. Among them, silicon oxide, kaolin, titanium oxide, calcium carbonate, magnesium carbonate and the like can be preferably used. Known surface treatments are applied to these inorganic particles, for example, JP-A-62-223339 and JP-A-63-3.
You may perform the process shown by 12345 gazette, Unexamined-Japanese-Patent No. 63-280763, etc. Further, these inorganic particles may be used in combination of two or more kinds.

The amount of the organic polymer fine particles added to the polyester is 0.01 to 10% by weight. Preferably 0.0
It is desirable that the content is 3 to 8% by weight, and more preferably 0.05 to 6% by weight, in terms of flatness and wear resistance. The amount of the inorganic particles added to the polyester is 0.001 to 10 by weight, preferably 0.005 to 8 by weight, and more preferably 0.01 to 6 by weight with respect to the organic polymer particles.
Is desirable in terms of flatness and wear resistance. The ratio of the particle size of the organic polymer particles to the inorganic particles (particle size of the inorganic particles / particle size of the organic polymer particles) is preferably 0.1 to 10.
When it is 0, particularly preferably 0.2 to 30, running property and wear resistance are good, which is desirable.

When fine organic polymer fine particles and inorganic particles are used in combination, the hardness of the protrusions has a distribution when the film runs at high speed, and it is possible to achieve both running properties and abrasion resistance.

The method of adding the organic polymer fine particles and the inorganic particles of the present invention is not particularly limited, and the organic particles and the inorganic particles may be added simultaneously or separately. For example, it can be added as a glycol slurry of the polyester raw material during the polyester production process, that is, during the transesterification, esterification, polycondensation reaction, or during the kneading of the molten polyester.

When the organic polymer fine particles are added alone,
It is preferable to add water and / or organic compound slurry having a boiling point of 200 ° C. or less to the polyester as fine organic polymer particles in a vent type extruder, and remove water and / or an organic compound having a boiling point of 200 ° C. or less under heating and reduced pressure. However, the method obtained by melt-kneading is more preferable because the dispersibility is further improved. The vent-type molding machine is a melt molding machine having at least one vent hole, and may be, for example, an extrusion molding machine or an injection molding machine. At least one of the vent holes for removing water and / or an organic compound having a boiling point of 200 ° C. or lower needs to be kept under reduced pressure. The degree of pressure reduction in the vent hole is preferably maintained at 100 Torr or less, more preferably 50 Torr or less, still more preferably 30 Torr or less. Boiling point 2
Examples of organic compounds having a temperature of 00 ° C. or lower include alcohols such as methanol, ethanol and ethylene glycol, hydrocarbon compounds such as benzene and toluene, and other compounds such as esters, ketones and amines.
There is no particular limitation. Of these, water is preferable from the viewpoints of handling properties and removability. Of course, the water and / or the organic compound may be a mixed solvent of two or more kinds, in which case a water-rich mixed solvent is preferable.

According to this method, the organic polymer fine particles can be added to and mixed with the polyester in the state of water and / or an organic compound slurry having a boiling point of 200 ° C. or less. For example, when added during the polyester synthesizing reaction, the adverse effects such as significant delay of the polyester synthesizing reaction due to water or a surfactant can be avoided, and the workability is improved. Further, even crosslinked polymer particles having relatively poor heat resistance can be mixed with polyester. When the inorganic particles are added separately from the organic polymer fine particles, the method of adding the inorganic particles as an ethylene glycol slurry is preferable from the viewpoint of dispersibility.

As described above, in the present invention, the organic polymer fine particles and the inorganic particles may be added simultaneously or separately, or the respective master polymers may be produced and blended and used. Further, it may be used by diluting it with polyester containing substantially no particles.

Further, in the polyester of the present invention, a metal compound catalyst of a compound such as lithium, sodium, calcium, magnesium, manganese, zinc, antimony, germanium and titanium which is usually used in the production of polyester, and a phosphorus compound as a color preventing agent. Etc. may be included.

The film of the present invention can be used as a monolayer film, of course, but when it is used in the form of a biaxially oriented film after being laminated on at least one side, the film surface has good uniformity, easy slippage and abrasion resistance. Therefore, it is preferable. In this case, a usual polyethylene terephthalate film or the like is preferably used as the base film.

The film thickness of the laminated portion in the above is 0.1 to 10 times the average particle diameter of the added inorganic particles,
In particular, if it is 0.1 to 5 times, slipperiness and wear resistance are particularly good, which is preferable.

As a laminating method in the present invention, a known laminating method such as melt coextrusion can be appropriately used.

[0034]

The present invention will be described in detail below with reference to examples. The characteristic values of the obtained polyester were measured according to the following methods.

(A) Particle Size of Particles The average particle size of the organic polymer particles and the inorganic particles was determined by the particle equivalent spherical diameter corresponding to 50% by volume measured by electron micrograph of the particles. The equivalent sphere diameter is the diameter of a sphere that has the same volume as the particle.

(B) Intrinsic Viscosity of Polymer Measured at 25 ° C. using o-chlorophenol as a solvent.

(C) Thermal Decomposition Temperature of Organic Polymer Fine Particles Rigaku Denki TAS-100 in nitrogen atmosphere under heating rate 2
The thermobalance weight loss curve at 0 ° C / min was measured. 10% was taken as the thermal decomposition temperature.

(D) Film Properties (1) Surface Roughness Ra (μm) Measured using a stylus type surface roughness meter according to JIS-B-0601 (cutoff value 0.08 mm, measurement length 4 m).
m). (2) Sliding property (μk) A film is slit into ½ inch, and a tape running tester TBT-300 type (manufactured by Yokohama System Research Co., Ltd.)
Was struck in an atmosphere of 20 ° C. and 55% RH, and the initial μk was calculated from the following formula. μk = 0.733 log (T ₁ / T ₂ ), where T ₂ is the inlet tension and T ₁ is the outlet tension. The guide diameter is 6 mmφ, the guide material is SUS27 (surface roughness 0.2S), the winding angle is 180 °, and the running speed is 3.
It is 3 cm / sec. Those having a μk of 0.35 or less have good slipperiness. Here, μk of 0.35 is a critical value for determining whether the slipperiness during film processing or as a product becomes extremely poor.

(3) Abrasion resistance (scraping by fast-forwarding / rewinding) A magnetic coating material having the following composition is applied to a film by a gravure roll, magnetically oriented, and dried. In addition, a small test calendar device (steel roll / nylon roll,
(5 stages), temperature: 70 ° C., linear pressure: 200 kg / cm, and then calendaring is performed at 70 ° C. for 48 hours. The above tape raw material was slit to 1/2 inch to prepare a pancake. A length of 250 m from this pancake was incorporated into a VTR cassette to obtain a VTR cassette. (Composition of magnetic paint) -Co-containing iron oxide: 100 parts by weight-Vinyl chloride / vinyl acetate copolymer: 10 parts by weight-Polyurethane elastomer: 10 parts by weight-Polyisocyanate: 5 parts by weight-Lecithin: 1 part by weight-Methyl ethyl ketone : 75 parts by weight Methyl isobutyl ketone: 75 parts by weight Toluene: 75 parts by weight Carbon black: 2 parts by weight Lauric acid: 1.5 parts by weight This video tape is fast-forwarded and rewound repeatedly on a commercial VCR 50 Judging was performed by judging the amount of shavings adhering to the tape running surface and the metal bottle in the cassette. The characteristics were rated as 1st and 2nd grade by visual inspection according to the following criteria. Almost no shavings adhered: Class 1 Small amount of shavings adhered: Class 2 Large amount of shavings adhered: Class 3

In the examples, "parts" means "parts by weight" unless otherwise specified. The abbreviations in each table are the abbreviations of the following compounds. The value of the added amount in parentheses in each table is the content of each particle in the film. BA: Butyl acrylate EVB: Ethyl vinyl benzene DVB: Divinyl benzene 2-EHA: 2-Ethylhexyl acrylate ST: Styrene

Example 1 An undried polyethylene terephthalate chip having an intrinsic viscosity of 0.670 containing 0.3% by weight of water was melted into a polymer state by using a vent type twin-screw extruder and 5% by weight. Styrene-ethylvinylbenzene-divinylbenzene (weight ratio 10/35/50) copolymer particles (pyrolysis temperature 410 ° C) having an average particle diameter of 0.02 µm dispersed as a water slurry of % Was added. The polymer (I) obtained had an intrinsic viscosity of 0.641.

Next, 100 parts of dimethyl terephthalate,
Transesterification was carried out by adding 0.06 part of magnesium acetate as a catalyst to 64 parts of ethylene glycol.
Next, 0.03 part of antimony trioxide and 0.03 part of trimethyl phosphate were added, and an ethylene glycol slurry containing 10% by weight of calcium carbonate particles having an average particle diameter of 0.5 μm was added to the polymer so that the content of the particles was 0.5%. Polycondensation reaction was carried out by adding 2% by weight to polyester. The polymer (II) obtained had an intrinsic viscosity of 0.629.

The organic polymer fine particle-containing polymer (I), the inorganic particle-containing polymer (II) and particle-free polyethylene terephthalate are contained in the film in an amount of 0.2% by weight of the organic polymer fine particles, and the inorganic particles are Were mixed so as to have a content of 0.2% by weight to obtain a polyester composition.
Further, the polyester composition was dried, melt-extruded by an extruder at 290 ° C., and rapidly cooled by a casting drum to obtain an unstretched sheet. Subsequently, this was stretched 3.3 times in the machine direction at 90 ° C. and 3 times in the transverse direction, and then heat treated at 220 ° C. for 15 seconds to obtain a biaxially stretched film having a thickness of 12 μm. The polymer properties and film properties are shown in Table 1, and were excellent in flatness and abrasion resistance.

[0044]

[Table 1] Example 2 100 parts of dimethyl terephthalate, 5 ethylene glycol
8 parts, 0.06 part of magnesium acetate as a catalyst and 0.03 part of antimony trioxide are added, and methanol is distilled off while the temperature is raised to 230 ° C. to carry out a transesterification reaction. Thereafter, 0.05 part of trimethyl phosphate was added and dispersed as a 5 wt% ethylene glycol slurry, and 2-ethylhexyl acrylate-ethyl vinyl benzene-divinyl benzene having an average particle diameter of 0.02 μm (weight ratio 50/20/25). Copolymer particles (thermal decomposition temperature of 380 ° C.) and silicon dioxide particles having an average particle size of 0.6 μm dispersed as an ethylene glycol slurry having a concentration of 10% by weight are contained in an amount of 1% by weight of organic polymer fine particles with respect to polyester. , So that the content of silicon dioxide particles is 0.6% by weight. After that, the reaction mixture was transferred to a polycondensation reaction tank and the pressure was reduced while raising the temperature to 290 ° C. for polycondensation. The polymer (III) obtained had an intrinsic viscosity of 0.631. The obtained polymer was diluted 1/5 times with non-particle diameter polyethylene terephthalate to obtain the polyester composition shown in Table 1. After drying, it was melt extruded by an extruder at 290 ° C. and rapidly cooled by a casting drum to obtain an unstretched sheet. Obtained. Then, stretching and heat treatment under the same conditions as in Example 1,
A biaxially stretched film was obtained. The polymer properties and film properties are shown in Table 1, and were excellent in flatness and abrasion resistance.

Examples 3 to 5 Polyester compositions shown in Table 1 in the same manner as in Example 1 except that the composition, the particle size, the addition amount of the organic polymer fine particles, the type of inorganic particles, the particle size, and the addition amount were changed. A biaxially stretched film was obtained. The polymer characteristics and the film characteristics are as shown in Table 1, and the film characteristics were good in both cases. In particular, in Example 4, methacrylic acid was added to the organic polymer fine particles, polymerization was further performed, and then NaOH was added to add functional group -C.
Although OONa was introduced, the flatness was excellent and the wear resistance was also good.

Example 6 An undried polyethylene terephthalate chip having an intrinsic viscosity of 0.670 containing 0.3% by weight of water was melted into a polymer state by using a vent type twin-screw extruder to obtain 5% by weight of the polymer chip. Butyl acrylate-ethyl vinyl benzene-divinyl benzene (weight ratio 40/25/30) copolymer particles (pyrolysis temperature 390 ° C.) having an average particle size of 0.03 μm dispersed as an aqueous slurry was 1 weight per polymer. % Was added. The obtained polymer (I
V) had an intrinsic viscosity of 0.638.

Next, 100 parts of dimethyl terephthalate,
Transesterification was carried out by adding 0.06 part of magnesium acetate as a catalyst to 64 parts of ethylene glycol.
Next, 0.03 part of antimony trioxide and 0.03 part of trimethyl phosphate were added, and an ethylene glycol slurry containing 10% by weight of zirconium oxide particles having an average particle diameter of 0.02 μm was added to the polymer so that the content of the particles was 0.3%. 2% by weight
Was added to the polyester so that the polycondensation reaction was performed. The polymer (V) obtained had an intrinsic viscosity of 0.628. These polymers (IV) and (V) were mixed with the polymer (II) obtained in Example 1 and particle-free polyethylene terephthalate (3: 1: 1: 5) to obtain polyester compositions shown in Table 1. .

Further, both sides of the particle-free polyethylene terephthalate were melt coextruded at 290 ° C. to obtain a laminated unstretched film. Then, the film was stretched and heat-treated under the same conditions as in Example 1 to give a particle-free polyethylene terephthalate layer thickness of 11 μm, and a polyethylene terephthalate composition layer containing organic polymer particles and inorganic particles having a thickness of 0.1 μm.
A biaxially stretched film having 5 μm laminated on both sides was obtained. When this film was evaluated, as shown in Table 1, Ra =
The film was 0.019 μm, μk = 0.30, and the abrasion resistance was particularly good.

Comparative Example 1 A water slurry of butyl acrylate-divinylbenzene (weight ratio 70/25) copolymer particles having an average particle diameter of 0.02 μm was added to a polymer in the same manner as in Example 1 to obtain the polymer. 1/2 with particle-free polyethylene terephthalate
It was diluted twice to obtain the polyester composition shown in Table 2, and a biaxially stretched film was obtained in the same manner as in Example 1. The polymer characteristics and the film characteristics are as shown in Table 2, and the flatness and wear resistance deteriorated.

[0050]

[Table 2] Comparative Examples 2 and 5 A polyester composition and a biaxially stretched film were obtained in the same manner as in Example 2, except that the type of added particles, the amount added, etc. were changed. The polymer characteristics and the film characteristics are as shown in Table 2, and the abrasion resistance deteriorated. In Comparative Example 5, two kinds of inorganic particles having different particle sizes and different kinds were used, but the film characteristics were deteriorated.

Comparative Examples 3, 4 and 6 A polyester composition and a biaxially stretched film were obtained in the same manner as in Example 2, except that the type of added particles, the addition amount and the like were changed. Polymer properties and film properties are shown in Table 2, and a film having good flatness and abrasion resistance was not obtained.

[0052]

Since the polyester composition of the present invention uses both organic polymer fine particles having a specific particle diameter and inorganic particles in combination, the dispersibility of the particles is good and the flatness and abrasion resistance when formed into a film are improved. It has excellent properties. Therefore, it is suitable for magnetic tape applications, photographs, plate making applications, condenser applications, and the like. Furthermore, when a laminated film is formed using the composition of the present invention, a film having particularly good flatness and abrasion resistance can be obtained.

Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area C08L 101: 00) B29K 67:00 B29L 7:00 4F

Claims (3)

[Claims] 1. A particle size of 0.002 μm or more and 0.10 μm
0.01 to 10% by weight of organic polymer fine particles having a particle size of less than 0.005 μm and a particle size of 0.002 μm or more
A thermoplastic polyester composition containing inorganic particles of less than m in a weight ratio of 0.001 to 10 with respect to organic polymer particles. 2. A biaxially oriented polyester film comprising the polyester composition of claim 1. 3. A biaxially oriented laminated polyester film, which is obtained by laminating the polyester composition of claim 1 on at least one side.