JP2000327807A - Polyester film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a film having stable tearing properties while maintaining low hygroscopicity, gas barrier properties, transparency and the like by preparing a raw material comprising in a specific ratio a polyester comprising a dicarboxylic acid and a diol, and a material containing a specific amount or more of a polytetrafluoroethylene. SOLUTION: A polyester film is made from a raw material comprising 80-99.95 mass % of a polyester comprising a dicarboxylic acid such as terephthalic acid and the like and a diol such as ethylene glycol and the like and 0.05-20 mass % of a powder material obtained by mixing 1-90 mass % of polytetrafluoroethylene particles having a particle size of not larger than 10 μm with 99-10 mass % of an organic polymer. The content of the polytetrafluoroethylene in the film is set to 0.04-5 mass %. If further necessary, fillers such as particulate silica or the like, pigments, stabilizers and the like are compounded. The monomers constituting the inorganic polymer are desirably those containing at least 30 mass % of aromatic vinyl monomers such as styrene and the like, and vinyl cyanide monomers such as acrylonitrile and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester film, and more particularly to a polyester film having excellent tearability and useful as a packaging material for foods, daily necessities and the like.

[0002]

2. Description of the Related Art Conventionally, packaging bags using various plastic films have been widely used for packaging foods, daily necessities, medicines, miscellaneous goods and the like. Among them, packaging bags in which two or three or more layers of a non-oriented plastic which can be heat-sealed with a plastic film such as a biaxially stretched polyester film are widely used. Biaxially stretched polyester film is excellent in low moisture absorption, gas barrier properties, transparency, mechanical strength, durability, moisture resistance, mechanical strength, heat resistance, oil resistance, tubular method, flat simultaneous biaxial stretching method It is manufactured using a flat-type sequential biaxial stretching method and the like, and is one of films widely used in the food packaging field and the like.

However, a packaging bag using a biaxially stretched polyester film has a drawback that tear-openability is poor. There is a method of providing a notch to improve tear openability, but when tearing from the notch, a phenomenon that often does not tear linearly occurs, the contents are scattered and wasted, and clothes are stained. Trouble may occur.

One of the easy-opening materials having excellent linearity when the film is torn is a film obtained by laminating a uniaxially stretched polyolefin film as an intermediate layer.
As an example of such a film, there is, for example, a three-layer laminated film composed of a biaxially oriented polyester film / a uniaxially oriented polyolefin film / an unoriented polyolefin film. However, such 3
A laminated film having a layer structure has a problem in terms of cost since an intermediate layer must be provided, and its use is limited.

As a method of imparting tear linearity to the biaxially stretched polyester film itself, a different polymer component exhibiting a phase-separated form with a polyester mainly containing an aromatic dicarboxylic acid such as terephthalic acid is added. A way to do that has been proposed. For example, JP-A-10-16
No. 8293 discloses a method of adding a polyether polyester block copolymer composed of polytetramethylene glycol and polybutyl terephthalate (PBT) to polyethylene terephthalate (PET). However, this method is a method of adding a second component that melts in the same manner as polyester at the time of melt shaping of the polyester. Therefore, in order to obtain a clear improvement in tearability, for example, a large amount of 5% to 10% is used. Requires the addition of heterogeneous components. Furthermore, film forming properties caused by the addition of different components,
In order to avoid a decrease in transparency and mechanical strength, there has been a problem that new restrictions are imposed on the composition and the production method.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above circumstances, and solves such a problem by providing a polyester film having low moisture absorption, gas barrier properties, transparency, and the like.
It is an object of the present invention to provide a polyester film having stable tearability while maintaining advantages such as mechanical strength.

[0007]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, formed a film using polyester and a material containing a specific amount of polytetrafluoroethylene as raw materials. It has been found that the above problem can be solved by forming a film.

The polyester film of the present invention comprises a polyester comprising a dicarboxylic acid and a diol.
95% by mass and 1% by mass of polytetrafluoroethylene
It is characterized in that 0.05 to 20% by mass of the material contained above is used as a raw material. By adopting such a polyester film, it is possible to obtain a polyester film having a stable tear property without impairing the advantages of the polyester film such as low moisture absorption, gas barrier properties, transparency, and excellent mechanical strength. it can.

In the above polyester film,
It is desirable that the material containing 1% by mass or more of polytetrafluoroethylene is composed of 1 to 90% by mass of polytetrafluoroethylene particles and 99 to 10% by mass of an organic polymer. Further, the particle diameter of the polytetrafluoroethylene is desirably 10 μm or less.

Further, in the above polyester film, it is preferable that 70 mol% or more of the dicarboxylic acid is terephthalic acid and 70 mol% or more of the diol is ethylene glycol.

In the above polyester film, the content of polytetrafluoroethylene is 0.0
Desirably, the content is 4 to 5% by mass. Furthermore, it is desirable that the polyester film is biaxially stretched.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The polyester film of the present invention comprises a polyester 8 comprising a dicarboxylic acid and a diol.
It is a polyester film made from 0 to 99.95% by mass and 0.05 to 20% by mass of a material containing 1% by mass or more of polytetrafluoroethylene (hereinafter abbreviated as “PTFE”). If the content of PTFE is 1% by mass or more and less than 0.05% by mass, excellent tearability may not be obtained. If it exceeds 20% by mass, the advantages of the polyester film, such as excellent low moisture absorption, gas barrier properties, transparency, and mechanical strength, may be impaired.

The content of PTFE in the polyester film obtained from the above-mentioned raw materials is set to 0.04 to 5% by mass. When the content of PTFE is less than 0.04% by mass, excellent tearability may not be obtained. If it exceeds 5% by mass, advantages of the polyester film such as transparency and durability tend to be impaired.

The polyester used in the polyester film of the present invention includes a polycondensate obtained from a dicarboxylic acid and a diol. Examples of the dicarboxylic acids include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyldicarboxylic acid, and diphenoxyethanedicarboxylic acid; and aliphatic acids such as adipic acid, sebacic acid, azelaic acid, and decanedicarboxylic acid. Dicarboxylic acids; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, etc .; and one or more of these can be used.

Considering the mechanical properties of the polyester film obtained by using dicarboxylic acid, terephthalic acid and naphthalenedicarboxylic acid are preferred, and considering cost, terephthalic acid and isophthalic acid are preferred. From the viewpoint of both cost and mechanical properties, it is most preferred that 70 mol% or more of the dicarboxylic acids constituting the polyester is terephthalic acid.

Examples of the diol include aliphatic glycols such as ethylene glycol, diethylene glycol, trimethylene glycol, tetramethylene glycol, neopentyl glycol, hexamethylene glycol, dodecamethylene glycol, triethylene glycol, tetraethylene glycol, and polyethylene glycol; Alicyclic glycols such as cyclohexanedimethanol; aromatic diols such as bisphenols, hydroquinone and 2,2-bis (4-β-hydroxyethoxyphenyl) propane;
Species or two or more can be used.

Considering the mechanical properties and cost of the polyester film obtained by using a diol, ethylene glycol, diethylene glycol, 1,4-cyclohexanedimethanol, 2,2-bis (4-β-hydroxyethoxyphenyl) propane Considering the versatility as a film, in order to highly balance the properties such as oil resistance and heat resistance in addition to the mechanical properties, 70% by mole or more of the diol constituting the polyester is preferably ethylene glycol. Most preferred. Furthermore, in order to ensure the mechanical properties, gas barrier properties, etc. of the polyester film, the intrinsic viscosity [η] measured in an equivalent solvent mixture of phenol and tetrachloroethane at 25 ° C. is 0.5 dl / g or more. It is preferred that

Further, in the material containing 1% by mass or more of PTFE used in the polyester film of the present invention,
The content of the FE particles is preferably from 1 to 90% by mass, more preferably from 8 to 90% by mass. PTF
When the E content is less than 1% by mass, the effect of improving tearability becomes insufficient, and when it exceeds 90% by mass, the smoothness and transparency of the film are easily impaired.

Further, if the particle size of PTFE in the PTFE-containing material is too large, it tends to be difficult to uniformly disperse PTFE in the polyester, so that it is preferably 10 μm or less, more preferably. Is 0.05 to 1.0 μm. When the particle diameter of the PTFE exceeds 1.0 μm, it becomes difficult to disperse the PTFE in water or the like, and the method of adjusting the PTFE-containing material may be restricted.

The material containing 1% by mass or more of PTFE is preferably a powder obtained by mixing 1 to 90% by mass of PTFE particles and 99 to 10% by mass of an organic polymer. As a material containing such PTFE, for example, an aqueous dispersion of PTFE particles having a particle diameter of 0.05 to 1.0 μm and an aqueous dispersion of organic polymer particles are mixed, and the mixture is powdered by coagulation or spray drying. Solidified or PT having a particle diameter of 0.05 to 1.0 μm
A polymer obtained by polymerizing a monomer constituting an organic polymer in the presence of an aqueous dispersion of FE particles, and then coagulating or spray-drying to obtain a powder, or a particle diameter of 0.05 to
In a dispersion obtained by mixing an aqueous dispersion of 1.0 μm PTFE particles and an aqueous dispersion of organic polymer particles, the vinyl monomer is emulsion-polymerized and then powdered by coagulation or spray drying. And the like.

In order to obtain such a material containing PTFE, it is preferable to use a particle size of 0.05 to 1.0 μm.
Is obtained by polymerizing a tetrafluoroethylene monomer by emulsion polymerization using a fluorine-containing surfactant.

In the emulsion polymerization of the PTFE particles, PT
As long as the properties of the FE are not impaired, the copolymer component may be a fluorine-containing olefin such as hexafluoropropylene, chlorotrifluoroethylene, fluoroalkylethylene, or perfluoroalkylvinyl ether, or a fluorine-containing alkyl such as perfluoroalkyl (meth) acrylate. (Meth) acrylate or the like can be used.
The amount of the copolymer component used at this time is preferably not more than 10% by weight based on tetrafluoroethylene.

Examples of commercially available raw materials for the aqueous dispersion of PTFE particles include Fluon AD manufactured by Asahi ICI Fluoropolymer.
-1, AD-936, Polyflon D manufactured by Daikin Industries, Ltd.
-1, D-2, Teflon 30J manufactured by DuPont-Mitsui Fluorochemicals, and the like.

On the other hand, examples of monomers constituting the organic polymer include styrene, α-methylstyrene, p-methylstyrene, o-methylstyrene, t-butylstyrene,
aromatic vinyl monomers such as o-ethylstyrene, p-chlorostyrene, o-chlorostyrene, 2,4-dichlorostyrene, p-methoxystyrene, o-methoxystyrene and 2,4-dimethylstyrene; methyl acrylate , Methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, dodecyl acrylate, dodecyl methacrylate, tridecyl acrylate, tridecyl methacrylate ,
Octadecyl acrylate, octadecyl methacrylate,
(Meth) acrylate monomers such as cyclohexyl acrylate and cyclohexyl methacrylate; vinyl cyanide monomers such as acrylonitrile and methacrylonitrile; α, β-unsaturated carboxylic acids such as maleic anhydride; N-phenylmaleimide , N-methylmaleimide,
Maleimide monomers such as N-cyclohexylmaleimide; epoxy group-containing monomers such as glycidyl methacrylate; vinyl ether monomers such as vinyl methyl ether and vinyl ethyl ether; vinyl carboxylate monomers such as vinyl acetate and vinyl butyrate Α-olefins such as ethylene, propylene and isobutylene; butadiene,
Examples include diene monomers such as isoprene and dimethylbutadiene.

These monomers can be used alone or in combination of two or more. In consideration of the cost, mechanical properties, and transparency of the obtained polyester film, one of aromatic vinyl monomer and vinyl cyanide monomer may be used.
Monomers containing at least 30% by mass of one or more species are preferred.

As such a material containing PTFE, one or more kinds can be used as a raw material of the polyester film of the present invention.

The polyester film of the present invention can be produced, for example, by the following method. First, PTFE
The dispersion obtained using the aqueous dispersion of the particles and the aqueous dispersion of the organic polymer particles is poured into hot water in which metal salts such as calcium chloride and magnesium sulfate are dissolved, and salting out is performed.
After solidification, the powder is dried or spray-dried to obtain a powdered PTFE-containing material. This PTFE
Is mixed into a heat extruder and extruded into a sheet from a die orifice of a T-die to produce an unstretched sheet. T
The sheet extruded from the die orifice of the die is wound tightly around a cooling drum by an electrostatic application casting method or the like and cooled, and then at a temperature of 80 to 140 ° C. and 3.0 to 5.0, respectively, vertically and horizontally. Stretched at a magnification of 20 times and then at a temperature of 20
Heat-treated at 0 to 245 ° C to obtain a biaxially stretched film.

The method of mixing the polyester and the material containing PTFE is not particularly limited, and examples thereof include generally known methods using a single-screw extruder, a twin-screw extruder, a batch kneader, a roll, or the like. it can. Also, PT
It is also possible to increase the ratio of the material containing FE to prepare a masterbatch mixed with polyester in advance, and then mix the masterbatch and polyester with a desired composition to obtain a raw material.

As the biaxial stretching method, any of a tenter simultaneous biaxial stretching method and a sequential biaxial stretching method using a roll and a tenter may be used. Further, a biaxially stretched film may be manufactured by a tubular method.

Such a polyester film is composed of a polyester 80 to 9 comprising a dicarboxylic acid and a diol.
Since 9.95% by mass and 0.05 to 20% by mass of a material containing 1% by mass or more of PTFE are used as raw materials, they are excellent in low hygroscopicity, gas barrier properties, transparency, mechanical strength and the like. And a stable polyester film having the advantage of the conventional polyester film.

Further, the material containing PTFE is
By using E1 to 90% by mass and organic polymer 99 to 10% by mass, good tearability can be obtained without impairing the smoothness and transparency of the obtained polyester film. Further, when the particle size of PTFE is 1
By setting the particle size to 0 μm or less, P using an aqueous PTFE dispersion
Adjustment of the TFE-containing material is facilitated.

Further, by controlling the content of tetrafluoroethylene in the polyester film to be 0.04 to 5% by mass, it is possible to maintain good transparency and fluidity while obtaining excellent tearing properties. Can be.

Further, by making at least 70 mol% of the dicarboxylic acid constituting the polyester into terephthalic acid and making at least 70 mol% of the diol ethylene glycol, a polyester film having excellent mechanical properties can be obtained. In addition, the cost can be kept low.

Further, by forming a biaxially stretched film, excellent strength and durability required for a packaging material and the like can be obtained, so that an industrially useful polyester film can be obtained.

As described above, the polyester film of the present invention may be a biaxially stretched film, but may be an unstretched film or a uniaxially stretched film.
It is not particularly limited.

The polyester film of the present invention may be subjected to a surface treatment such as a corona discharge treatment, a surface hardening treatment, a plating treatment, a coloring treatment, or various coating treatments, if necessary.

Further, in the polyester film of the present invention, if necessary, a filler such as fine particle silica,
Various additives such as dyes, pigments and stabilizers may be blended.

[0038]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments. In the following Reference Examples, Examples and Comparative Examples, the raw materials used for the evaluation and the measuring methods are as follows. “Parts” and “%” mean “parts by mass” and “% by mass” unless otherwise specified.

Measurement method (1) Solid content: The solid content was determined by drying the particle dispersion at 170 ° C. for 30 minutes. (2) Particle size distribution, weight average particle size: A particle dispersion diluted with water was used as a sample liquid and subjected to dynamic light scattering (ELS800, manufactured by Otsuka Electronics Co., Ltd., temperature 25 ° C., scattering angle 90 °). It was measured. (3) Zeta potential (surface potential): 0.01
The sample was diluted with a mol / l aqueous solution of NaCl, and this was used as a sample solution, which was measured by electrophoresis (ELS800, manufactured by Otsuka Electronics Co., Ltd., temperature 25 ° C., scattering angle 10 °). (4) Intrinsic viscosity [η]: Measured at 25 ° C. using an equal weight mixture of phenol and tetrachloroethane as a solvent. (5) Tear linearity: A rectangular film piece of 205 mm in the longitudinal direction (MD direction) and 40 mm in the width direction (TD direction) of the film is cut out, and a length of 5 mm is provided at the center of one short side of this film piece. 30 samples with a notch were prepared, and the sample was torn by hand in the MD direction from the notch, and the number of samples whose tear propagation end reached the short side facing the side where the notch was cut was evaluated as an evaluation value of tear linearity in the MD direction. And (6) Tensile strength: 10 mm in the longitudinal direction of the film and 100 mm in the width direction were cut out into strip-shaped test pieces, and ASTM-
It was measured according to D882.

[0040]

[Reference Example] Production of PTFE-containing material [Reference Example 1] First, 300 parts of distilled water and 2 parts of sodium dodecylbenzenesulfonate were mixed with a stirring device, a cooler, a thermocouple, a nitrogen inlet, and a reagent dropping device. The flask was charged and heated to 70 ° C. in a water bath under a nitrogen stream. After dissolving 0.0004 parts of ferrous sulfate, 0.0012 parts of disodium ethylenediaminetetraacetate, and 0.8 parts of sodium formaldehyde sulfoxylate in 5 parts of distilled water and adding to the contents, 30 parts of acrylonitrile and 70 parts of styrene were added. Department,
A mixture of 0.5 parts of cumene hydroxy peroxide was added to 3
After that, the mixture was continuously heated and stirred for 1 hour,
5.1%, weight average particle diameter 100 μm, surface potential −30
An aqueous dispersion of acrylonitrile-styrene copolymer particles of mV (hereinafter, referred to as “P-1”) was obtained.

Next, 5 parts of polyoxyethylene alkyl phenyl ether was contained with respect to 100 parts of PTFE, the solid content was 63.0%, the particle size distribution showed a single peak, the weight average particle size was 290 nm, and the surface potential was -20 mV. PTFE
To 833 parts of a particle dispersion of Asahi Glass Fluoropolymers Co., Ltd. (Fluon AD936), 1167 parts of distilled water was added, and an aqueous dispersion of PTFE particles having a solid content of 26.2% (hereinafter, referred to as “a”)
It is called "F-1". ) Got.

Subsequently, 239.0 parts of P-1 (60 parts of acrylonitrile-styrene copolymer) and 80 parts of F-
1 (20 parts of PTFE) was charged into a flask equipped with a stirrer, a cooler, a thermocouple, a nitrogen inlet, and a reagent dropping device, and stirred at room temperature under a nitrogen stream for 1 hour. Then in the water bath 8
Heat to 0 ° C. and stir for 1 hour. Further, after dissolving 0.0004 parts of ferrous sulfate, 0.0012 parts of disodium ethylenediaminetetraacetate, and 0.8 parts of sodium formaldehyde sulfoxylate in 5 parts of distilled water and adding the resulting mixture to the contents, 6 parts of acrylonitrile; A mixture of 14 parts of styrene and 0.1 part of cumene hydroxyperoxide was added dropwise over 30 minutes, and then heating and stirring were continued for 1 hour. No solid matter was separated, and a uniform particle dispersion was obtained. The solid content of the particle dispersion is 28.6%, and the weight average particle size is 220 nm.
Met.

The thus-obtained particle dispersion is poured into an aqueous calcium chloride solution, the solid is separated, filtered and dried to obtain a powdered PTFE-containing material (hereinafter referred to as “C-
1 ". ) Got. The obtained C-1 was molded using a press molding machine, an ultrathin section was collected from the molded product using a microtome, and observed with a transmission electron microscope without staining. As a result, PTFE was observed as a dark area,
No PTFE aggregates larger than μm were observed.

REFERENCE EXAMPLE 2 An aqueous dispersion (P-1) of acrylonitrile-styrene copolymer particles as in Reference Example 1.
298.8 parts (acrylonitrile-styrene copolymer 7)
5 parts) and 100 parts (25 parts of PTFE) of the same aqueous dispersion (F-1) of PTFE particles as in Reference Example 1.
And stirred for 1 hour at room temperature under a nitrogen stream, then heated to 70 ° C. in a water bath and stirred for 1 hour. No solid matter was separated, and a uniform particle dispersion was obtained. The solid content of the particle dispersion is 24.9%, and the weight average particle size is 220.
nm.

Using the particle dispersion thus obtained, a powdery PTFE-containing material (hereinafter referred to as "C-2") was obtained in the same manner as in Reference Example 1. Obtained C-
2 was observed with a transmission electron microscope in the same manner as in Reference Example 1. As a result, PTFE aggregates exceeding 10 μm were not observed.

Reference Example 3 The same aqueous dispersion (F-1) of PTFE particles as in Reference Example 1, 160 parts (PTFE 40 parts)
1.0 part of dodecylbenzenesulfonic acid and 70 parts of distilled water
The flask was charged in the same flask as in Reference Example 1 and heated to 70 ° C. in a water bath under a nitrogen stream. In addition, ferrous sulfate 0.00
04 parts, disodium ethylenediaminetetraacetate 0.00
After dissolving 12 parts and 0.8 parts of sodium formaldehyde sulfoxylate in 5 parts of distilled water and adding to the contents, a mixture of 18 parts of acrylonitrile, 42 parts of styrene and 0.3 part of cumene hydroxyperoxide is dropped in 90 minutes. Then, heating and stirring were continued for 1 hour. No solid matter was separated, and a uniform particle dispersion was obtained. The solid content of the particle dispersion was 33.2%, and the weight average particle size was 220 nm.

Using the particle dispersion thus obtained, a powdery PTFE-containing material (hereinafter referred to as "C-3") was obtained in the same manner as in Reference Example 1. Obtained C-
3 was observed with a transmission electron microscope in the same manner as in Reference Example 1. As a result, PTFE aggregates exceeding 10 μm were not observed.

[0048]

Examples 1 to 3 Intrinsic viscosity [η] is 0.75 dl
/ G of polyethylene terephthalate (PET) and C-1 to C-3 obtained in Reference Examples 1 to 3 so that the obtained polyester film has a PTFE content of 0.2%. The mixture was weighed in a ratio and melt-kneaded at a barrel temperature of 270 ° C. using a twin-screw extruder to obtain pellets. After drying the pellets, the extruded sheet is melt-extruded at a resin temperature of 280 ° C. using a single screw extruder equipped with a T-die. Obtained. Further, the obtained unstretched sheet was stretched 4.0 times at 90 ° C. in the machine direction by a roll stretching method and 3.5 times at 120 ° C. in the transverse direction by a tenter.
Heat treatment was performed at 5 ° C. to obtain a 15 μm thick biaxially stretched film.

[0049]

[Table 1]

[0050]

Comparative Example 1 The same polyethylene terephthalate (PET) as in Example 1 was used, and the thickness was 1 in the same manner as in Example 1.
A 5 μm biaxially stretched film was obtained.

The biaxially stretched films of Examples 1 to 3 and Comparative Example 1 thus obtained each had a smooth surface and were transparent. Further, the tear linearity and tensile strength of the biaxially stretched films of Examples 1 to 3 and Comparative Example 1 were measured. Table 1 shows the results.

From Table 1, it can be seen that Examples 1 to 3 containing PTFE were used.
It was confirmed that all the biaxially stretched films of Example 3 were superior to the biaxially stretched film of Comparative Example 1 in tear linearity. Moreover, it became clear that all the biaxially stretched films of Examples 1 to 3 had sufficiently excellent tensile strength equivalent to that of the biaxially stretched film of Comparative Example 1.

[0053]

As described above, the polyester film of the present invention comprises 80 to 99.95% by mass of a polyester comprising a dicarboxylic acid and a diol, and 0.05 to 20% by mass of a material containing 1% by mass or more of PTFE. % As a raw material, so that the polyester film has the advantages of a conventional polyester film having excellent moisture absorption, gas barrier properties, transparency, mechanical strength, and the like, and a stable tear property. Can be.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 27:18) B29K 27:18 67:00 (72) Inventor Atsunori Koshirai 20 Miyukicho, Otake City, Hiroshima Prefecture No. 1 Inside Mitsubishi Rayon Co., Ltd. Central Research Laboratory (72) Inventor Koji Nishida 20-1 Miyukicho, Otake City, Hiroshima Prefecture Mitsubishi Rayon Co., Ltd. Central Research Laboratory F-term (reference) 4F071 AA01 AA27 AA46 AH04 BB08 BC01 4F210 AA17 AA24K AG01 AH54 QC05 QG01 4J002 AC023 BB003 BC023 BD152 BE043 BF013 BF023 BG043 BG053 BG103 BH003 CF061 GG02

Claims (6)

[Claims] 1. A material containing 80 to 99.95% by mass of a polyester comprising a dicarboxylic acid and a diol, and 0.05 to 20% of a material containing 1% by mass or more of polytetrafluoroethylene.
A polyester film characterized in that the polyester film is prepared by using, as a raw material, a mass%. 2. The material containing 1% by mass or more of polytetrafluoroethylene is composed of 1 to 90% by mass of polytetrafluoroethylene and 99 to 10% by mass of an organic polymer. The polyester film as described. 3. The polyester film according to claim 2, wherein the particle diameter of the polytetrafluoroethylene is 10 μm or less. 4. The polyester according to claim 1, wherein at least 70 mol% of the dicarboxylic acid is terephthalic acid, and at least 70 mol% of the diol is ethylene glycol. the film. 5. The polyester film according to claim 1, wherein the content of the polytetrafluoroethylene is 0.04 to 5% by mass. 6. The polyester film according to claim 1, which is biaxially stretched.