JP2008266600A - Biaxially oriented film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biaxially oriented film excellent in the resistance to moist heat and dielectric breakdown properties. <P>SOLUTION: The biaxially oriented film is a film comprising polyester (a), polyimide (b), polyarylene sulfide (c) and a compatibilizer (d), wherein the content is in the ranges of (a) 50 to 98% by weight, (b) 1 to 30% by weight and 0.1 to 30% by weight (c) with respect to the total weight of the polyester (a), the polyimide (b) and the polyarylene sulfide (c), respectively, in the film; the polyimide (b) and the polyarylene sulfide (c) form dispersed phases, respectively; the mean dispersion diameters of the polyimide (b) and the polyarylene sulfide (c) are in the ranges of 1 to 50 nm and 50 to 500 nm, respectively; and the elongation half life of the film by a test on the resistance to moist heat is 30 hours or longer but 120 hours or shorter. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a biaxially oriented film having excellent moisture and heat resistance and dielectric breakdown characteristics. In particular, the film of the present invention is a biaxially oriented film that can be suitably used as a film for various industrial materials such as for electrical insulation, capacitors, packaging, ink ribbons, circuit boards, and solar cells.

  Polyester film uses various properties such as magnetic recording media, electrical insulation, capacitors, packaging, various industrial materials, etc. by utilizing excellent mechanical properties, thermal properties, electrical properties, surface properties, and heat resistance. Used for applications. In order to improve the quality in these applications, there is a demand for improvement in dimensional stability, heat resistance, and moist heat resistance, particularly in a high temperature environment. However, for example, a polyester film made of ethylene terephthalate alone may not have sufficient dimensional stability, heat resistance, and moist heat resistance under a high temperature environment.

  In recent years, in order to increase the heat resistance of a polyester film, methods such as blending other thermoplastic resins with polyester have been studied.

  About the blend of polyester and polyimide resin, the glass transition temperature which becomes a heat resistant parameter | index may rise with the increase in a polyimide resin fraction (for example, patent document 1).

  However, a composition comprising polyester and polyimide has a thermal dimensional stability in the vicinity of the glass transition temperature (100 to 120 ° C.) and mechanical long-term heat resistance at a high temperature in the vicinity of 150 to 200 ° C. as compared to the case of the polyester alone. Although it is excellent (for example, patent document 2), it may be inadequate about the heat-and-moisture resistance in 140 degreeC80% RH. When the heat and humidity resistance is insufficient, for example, in motor insulation films for electric car air conditioners that use refrigerants that have been developed in recent years, the film deteriorates during continuous use in a high temperature environment. This is not preferable because problems such as loss of insulation may occur.

In a film made of a polyarylene sulfide resin mainly composed of polyphenylene sulfide, a polyester resin mainly composed of polyethylene terephthalate, and a polyimide resin mainly composed of polyetherimide, a film having improved moisture and heat resistance has been proposed. However, the film according to Patent Document 3 still has insufficient moisture and heat resistance, and the dispersion of each resin in the film may be insufficient, and the film-forming property may be inferior (for example, Patent Document 3).
U.S. Pat. No. 4,141,927 Japanese Patent Laid-Open No. 14-245857 JP 2006-169512 A

  An object of the present invention is to obtain a biaxially oriented polyester film having excellent moisture and heat resistance and dielectric breakdown characteristics. Another object of the present invention is to obtain a biaxially oriented polyester film that exhibits excellent dimensional stability in a high-temperature environment or a high-humidity environment and is excellent in film-forming production stability.

The present inventors have found that the above problem can be solved mainly by the following configuration.
(1) A film containing polyester (a), polyimide (b), polyarylene sulfide (c) and compatibilizer (d). Polyester (a), polyimide (b), polyarylene sulfide (c) in the film ) In the range of (a) 50 to 98% by weight, (b) 1 to 30% by weight, (c) 0.1 to 30% by weight, polyimide (b) and polyarylene sulfide (c) ) Form a dispersed phase, the average dispersion diameter of polyimide (b) is in the range of 1 to 50 nm, the average dispersion diameter of polyarylene sulfide (c) is in the range of 50 to 500 nm. A biaxially oriented film having a period of 30 hours to 120 hours.
(2) The content of polyester (a) is in the range of (a) 50 to 90% by weight with respect to the total of polyester (a), polyimide (b), and polyarylene sulfide (c) in the film. The biaxially oriented film according to (1), wherein the content of sulfide (c) is in the range of (c) 1 to 30% by weight, and the elongation half-life of the film by a heat and humidity test is 60 hours to 120 hours .
(3) The biaxially oriented film according to (1) or (2), wherein the weight ratio of the polyimide (b) and the polyarylene sulfide (c) contained in the film satisfies the following formula.
0.01 ≤ c / b ≤ 3.0
(4) The biaxially oriented film according to any one of (1) to (3), wherein a silicon atom (Si) is contained in a dispersed interface phase of polyimide (b) or polyarylene sulfide (c) in the film. .
(5) The biaxially oriented film according to any one of (1) to (4), wherein the polyester (a) is polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate or a modified product thereof.
(6) The biaxially oriented film according to any one of (1) to (5), wherein the polyimide (b) is a polyetherimide.
(7) The biaxially oriented film according to any one of (1) to (6), wherein the polyarylene sulfide (c) is polyphenylene sulfide.
(8) The biaxially oriented film according to any one of (1) to (7), which is used as a magnetic recording medium.

  Since the biaxially oriented film of the present invention has few foreign substances and has excellent moisture and heat resistance and dielectric breakdown characteristics, various industries such as electrical insulation applications, capacitor applications, packaging applications, ink ribbon applications, circuit board applications, solar cell applications, etc. As a film for materials, its industrial value is extremely high.

  The biaxially oriented film of the present invention is a film containing polyester (a) and polyimide (b), polyarylene sulfide (c) and compatibilizer (d).

  The biaxially oriented film of the present invention contains polyester (a), polyimide (b), polyarylene sulfide (c), and the content thereof is polyester (a), polyimide (b), poly By satisfying (a) 50 to 98% by weight, (b) 1 to 30% by weight, and (c) 0.1 to 30% by weight based on the total amount of arylene sulfide (c), the film has excellent heat resistance and dielectric breakdown. Properties can be imparted.

  The polyester (a) in the present invention is a polymer having an ester bond in the main chain, and is a polymer containing at least 80% by weight of a polymer obtained by condensation polymerization of a diol and a dicarboxylic acid or an ester-forming derivative thereof. is there. Preferred examples include thermoplastic polyesters having an aromatic ring in the chain unit of the polymer. Specifically, usually, an aromatic dicarboxylic acid (or an ester-forming derivative thereof) and a diol (or an ester-forming derivative thereof) and / or Or the polymer or copolymer obtained by the condensation reaction which has hydroxycarboxylic acid as a main component is mentioned.

  Here, the dicarboxylic acid is represented by terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, adipic acid, sebacic acid or ester-forming derivatives thereof. Examples of the ester-forming derivative include dimethyl terephthalate, dimethyl isophthalate, and dimethyl phthalate. Two or more of these dicarboxylic acids can be used in combination. On the other hand, the diol is represented by ethylene glycol, butanediol, propanediol, trimethylene glycol, tetramethylene glycol, cyclohexanedimethanol and the like. Two or more of these diols can be used in combination.

  Specific polymers include, for example, polymethylene terephthalate, polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene isophthalate, polytetramethylene terephthalate, polyethylene-p-oxybenzoate, poly-1,4-cyclohexylene dimethylene terephthalate. Polyethylene-2,6-naphthalate or the like can be used.

  Of course, these polyesters may be a homopolymer or a copolymer. In the case of a copolymer, examples of the copolymer component include diol components such as diethylene glycol, neopentyl glycol, and polyalkylene glycol, adipic acid, and sebatin. Dicarboxylic acid components such as acid, phthalic acid, isophthalic acid and 2,6-naphthalenedicarboxylic acid, and hydroxycarboxylic acid components such as hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid may be contained.

  When the film contains polyester as a main component, it is excellent in terms of mechanical properties, thermal properties, electrical properties, surface properties, heat resistance, and the like.

  The intrinsic viscosity of the polyester (a) used in the present invention is preferably from 0.55 to 2.0 dl / g, from the viewpoint of melt kneading properties with polyimide and polyarylene sulfide, film-forming properties, and melt heat stability. Preferably it is 0.6-1.4 dl / g, Most preferably, it is 0.65-1.3 dl / g.

  The biaxially oriented film of the present invention contains polyester as a main component. In the present invention, this is defined as including 50 to 98% by weight of polyester with respect to the total of polyester (a), polyimide (b), and polyarylene sulfide (c) in the film.

  When the content of the polyester in the biaxially oriented film of the present invention is less than the above range, mechanical properties, thermal properties, electrical properties, surface properties, heat resistance, and workability deteriorate. When the above range is exceeded, the dimensional stability, heat resistance and heat and humidity resistance deteriorate. The content of the polyester in the biaxially oriented film of the present invention is preferably 50 to 90% by weight, more preferably, based on the total of the polyester (a), polyimide (b) and polyarylene sulfide (c) in the film. 60 to 88% by weight, more preferably 65 to 85% by weight.

  The polyester includes polyethylene terephthalate (hereinafter referred to as PET), polyethylene-2,6-naphthalate (hereinafter referred to as PEN), polypropylene terephthalate (hereinafter referred to as PPT), polybutylene terephthalate (hereinafter referred to as PBT) and / or a copolymer thereof. More preferably, and / or these modified products are contained. Particularly preferred is PET or PEN.

  A film mainly composed of PET, PEN, PBT, PPT and / or a copolymer thereof can be formed at low cost because it can be continuously formed by using a conventional melt film forming method and productivity can be improved. There is. Moreover, it is also practically suitable to use these polyesters as a mixture according to required properties such as moldability, heat resistance, toughness, and surface properties.

  The polyimide (b) referred to in the present invention is a melt-formable polymer containing a cyclic imide group, and may be any one that can meet the purpose of the present invention. Examples of the polyimide (b) include a polyetherimide containing an aliphatic, alicyclic or aromatic ether unit and a cyclic imide group as repeating units.

  When the film contains polyimide (b), the glass transition temperature of the film is likely to be higher than that of a film made only of polyester, so that the film is provided with excellent heat resistance and moist heat resistance.

  The biaxially oriented polyester film of the present invention contains 1 to 30% by weight of polyimide (b) based on the total of polyester (a), polyimide (b) and polyarylene sulfide (c) in the film. When the content of the polyimide (b) is less than the above range, the glass transition temperature rise of the film is not sufficient, so that the heat resistance and heat and humidity resistance are poor. On the other hand, when the above range is exceeded, the film-forming property of the film deteriorates, the production cost increases, and it becomes difficult to control the dispersion diameter within the range of the present invention. The content of the polyimide (b) is preferably 5 to 20% by weight, more preferably 8 to 15% by weight.

The polyimide (b) in the present invention preferably has a melt viscosity of 100 to 600 Pa · S at 350 ° C. and a shear rate of 100 sec ⁻¹ . When the melt viscosity is 100 to 600 Pa · S, the kneadability of the polyimide (b) and the polyarylene sulfide (c) tends to be improved. When it is in this range, the average dispersion diameter of the polyarylene sulfide (c) in the finally obtained film can be easily controlled to 50 to 500 nm, which is the definition of the present invention.

In the present invention, the melt viscosity [b] at a temperature of 350 ° C. and a shear rate of 200 sec ⁻¹ for the polyimide (b) and the melt viscosity [c] at a temperature of 350 ° C. and a shear rate of 200 sec ⁻¹ for the polyarylene sulfide (c) are: It is preferable to satisfy the relationship.
1/3 ≦ [c] / [b] ≦ 3
When the melt viscosity of the polyimide (b) and the polyarylene sulfide (c) is within the above range, the average dispersion diameter of the polyimide (b) and the polyarylene sulfide (c) in the polyester (a) is within the range of the present invention. In some cases, the film can be easily controlled, foreign matter in the film can be reduced, and excellent heat resistance and moist heat resistance can be imparted to the film.

  The polyimide (b) in the present invention is preferably a polyetherimide. The polyetherimide has good compatibility with the polyester (a) and may have excellent melt moldability and workability.

  Examples of such polyetherimide include, for example, US Pat. No. 4,141,927, Japanese Patent No. 2622678, Japanese Patent No. 2609912, Japanese Patent No. 2606914, Japanese Patent No. 2596565, and Japanese Patent No. 2596565. Polyetherimide described in Japanese Patent No. 2596566, Japanese Patent No. 2598478, Japanese Patent No. 2598536, Japanese Patent No. 2599171, Japanese Patent Laid-Open No. 9-48852, Japanese Patent No. 2655556, Polymers described in Japanese Patent No. 2564636, Japanese Patent No. 2564737, Japanese Patent No. 2563548, Japanese Patent No. 2563547, Japanese Patent No. 2558341, Japanese Patent No. 2558339, and Japanese Patent No. 2854580 Etc., but these But it is not limited.

  If the effect of the present invention is not impaired, the main chain of polyimide contains structural units other than cyclic imide and ether units, such as aromatic, aliphatic, alicyclic ester units, oxycarbonyl units, and the like. It does not matter.

  Further, if the effect of the present invention is not inhibited, structural units other than cyclic imide and ether units in the main chain of polyetherimide, for example, aromatic, aliphatic, alicyclic ester units, oxycarbonyl units, etc. It may be contained.

  Specific examples of the polyetherimide that can be preferably used in the present invention include polymers represented by the following general formula.

In the above formula, R ₁ is a divalent aromatic or aliphatic residue having 6 to 30 carbon atoms, and R ₂ is a divalent aromatic having 6 to 30 carbon atoms. From a residue, an alkylene group having 2 to 20 carbon atoms, a cycloalkylene group having 2 to 20 carbon atoms, and a polydiorganosiloxane group chain-terminated with an alkylene group having 2 to 8 carbon atoms A divalent organic group selected from the group consisting of: Moreover, as said R < ₁ >, R < ₂ >, the aromatic residue shown by the following formula group can be mentioned, for example.

  In the present invention, polyetherimide having a glass transition temperature of preferably 350 ° C. or lower, more preferably 300 ° C. or lower, and most preferably 250 ° C. or lower is preferable from the viewpoint of compatibility with the thermoplastic resin, cost, and melt moldability. 2,2-bis [4- (2,3-dicarboxyphenoxy) phenyl] propane dianhydride having a structural unit represented by the following formula, and a condensate of m-phenylenediamine or p-phenylenediamine, and these These copolymers and modified products are most preferred from the viewpoints of compatibility with thermoplastic resins, cost, melt moldability, and the like. This polyetherimide is commercially available from GE Plastics and is a registered trademark of "Ultem 1000", "Ultem 1010", "Ultem 1040", "Ultem 5000", "Ultem 6000", "Ultem 6050" and "Extem XH1015" series. Is known.

Or

The weight ratio b / a between the polyester (a) and the polyimide (b) contained in the biaxially oriented polyester film of the present invention is preferably in the range of 0.01 to 0.4. By being in the said range, the production cost can be lowered at the same time as imparting excellent heat and moisture resistance to the film. The range of the weight ratio b / a between the polyester (a) and the polyimide (b) is preferably 0.05 to 0.3, more preferably 0.1 to 0.25.

The polyarylene sulfide (c) referred to in the present invention is a homopolymer or copolymer having a repeating unit of the formula-(Ar-S)-as a main constituent unit. Examples of Ar include units represented by the following formulas (A) to (K), among which the formula (A) is particularly preferable.

(In the formula, R1 and R2 are substituents selected from hydrogen, an alkyl group, an alkoxy group and a halogen group, and R1 and R2 may be the same or different.)
As long as this repeating unit is a main structural unit, it can contain a small amount of branching units or crosslinking units represented by the following formulas (L) to (N). The amount of copolymerization of these branch units or cross-linking units is preferably in the range of 0 to 5 mol% when the total of-(Ar-S)-, branch units and cross-linking units is 100 mol%, preferably 1 mol. More preferably, it is in the range of% or less.

  Further, the polyarylene sulfide resin in the present invention may be a random copolymer, a block copolymer and a mixture thereof containing the above repeating unit.

  Representative examples of these polysulfide resins include, but are not limited to, polyphenylene sulfide, polyphenylene sulfide sulfone, polyphenylene sulfide ketone, random copolymers, block copolymers, and mixtures thereof.

  When the film contains polyarylene sulfide, the heat resistance and moist heat resistance of polyarylene sulfide are imparted to the biaxially oriented film of the present invention.

The biaxially oriented film of the present invention contains polyarylene sulfide (c) in an amount of 0.1 to 30% by weight based on the total of polyester (a), polyimide (b) and polyarylene sulfide (c) in the film. It is necessary, and more preferably 1 to 30% by weight.

When the content of the polyarylene sulfide (c) is less than the above range, the film has poor heat resistance and moist heat resistance. Moreover, when the said range is exceeded, the film formability of a film will deteriorate and production cost will become high. Moreover, it is inferior to the secondary workability of a film. Further, it may be difficult to control the dispersion diameter within the range of the present invention. A more preferable range of the content of the polyarylene sulfide (c) is 2 to 20% by weight, further preferably 3 to 15% by weight, and most preferably 3 to 5%.

  The polyarylene sulfide (c) is preferably polyphenylene sulfide.

  The polyphenylene sulfide (hereinafter referred to as PPS) referred to in the present invention is a resin containing preferably 80 mol% or more, more preferably 90 mol% or more of a phenylene sulfide unit represented by the following structural formula. When the phenylene sulfide component is less than 80 mol%, the crystallinity and heat transition temperature of the polymer are low, and the heat resistance and dimensional stability, which are the characteristics of PPS, may be impaired.

  As the repeating unit of the polyarylene sulfide used in the present invention, the structural formula represented by the above formula (A) is preferable, and representative examples thereof include polyphenylene sulfide, polyphenylene sulfide sulfone, polyphenylene sulfide ketone, Examples thereof include random copolymers, block copolymers, and mixtures thereof. A particularly preferred polyarylene sulfide is preferably polyphenylene sulfide (PPS) from the viewpoint of film properties and economy, and a p-phenylene sulfide unit represented by the following structural formula is preferably 80 as the main structural unit of the polymer. It is a resin containing mol% or more, more preferably 90 mol% or more, and still more preferably 95 mol% or more. When the p-phenylene sulfide component is less than 80 mol%, the crystallinity and thermal transition temperature of the polymer are low, and the heat resistance, dimensional stability, mechanical properties, dielectric properties, etc., which are the characteristics of PPS, may be impaired.

  In the PPS resin, if the repeating unit is less than 20 mol%, preferably less than 10 mol%, other units containing copolymerizable sulfide bonds may be included. As the repeating unit of less than 20 mol%, preferably less than 10 mol% of the repeating unit, for example, a trifunctional unit, an ether unit, a sulfone unit, a ketone unit, a meta bond unit, an aryl unit having a substituent such as an alkyl group, Examples include biphenyl units, terphenylene units, vinylene units, carbonate units, and the like, and specific examples include the following structural units. One or more of these can coexist. In this case, the structural unit may be either a random type or a block type copolymerization method.

  PPS consisting essentially of p-phenylene sulfide or PPS consisting of 1 mol% or less of trifunctional components and 99 mol% or more of p-phenylene sulfide is used as a film raw material for cost, film-forming properties, particularly at high temperatures. Most preferable from the viewpoint of performance and the like. In this case, the obtained PPS resin has a melting point of 280 to 290 ° C. and a glass transition temperature of 90 to 95 ° C.

  The melt viscosity of the PPS resin and the PPS resin composition is not particularly limited as long as melt kneading is possible. However, the melt viscosity is 50 to 5,000 Pa · s at a temperature of 315 ° C. and a shear rate of 1,000 (1 / sec). It is preferable that it is the range of this, More preferably, it is the range of 100-2,000 Pa.s.

  The PPS resin used in the present invention can be obtained by various methods, for example, a method for obtaining a polymer having a relatively small molecular weight described in JP-B-45-3368, or JP-B-52-12240 and JP-A-61-61. Although it can manufacture by the method of obtaining the polymer with comparatively large molecular weight described in 7332 gazette, it is not necessarily limited to these.

  In the present invention, the obtained PPS resin is subjected to crosslinking / polymerization by heating in air, heat treatment under an inert gas atmosphere such as nitrogen or reduced pressure, washing with an organic solvent, hot water, an acid aqueous solution, etc., acid anhydride It can also be used after various treatments such as activation with functional group-containing compounds such as products, amines, isocyanates and functional group disulfide compounds.

  Next, although the manufacturing method of PPS resin is illustrated, in this invention, it is not limited to this in particular. For example, sodium sulfide and p-dichlorobenzene are reacted in an amide polar solvent such as N-methyl-2-pyrrolidone (NMP) under high temperature and high pressure. If necessary, a copolymer component such as trihalobenzene can be included. Caustic potash or alkali metal carboxylate is added as a polymerization degree adjusting agent, and a polymerization reaction is performed at 230 to 280 ° C. After the polymerization, the polymer is cooled, and the polymer is filtered as a water slurry through a filter to obtain a granular polymer. This is stirred in an aqueous solution such as acetate at 30 to 100 ° C. for 10 to 60 minutes, washed several times with ion exchange water at 30 to 80 ° C. and dried to obtain a PPS powder. The powder polymer is washed with NMP at an oxygen partial pressure of 10 torr or less, preferably 5 torr or less, then washed several times with ion exchange water at 30 to 80 ° C., and dried under a reduced pressure of 5 torr or less. The polymer thus obtained is a substantially linear PPS polymer, and the melt crystallization temperature Tmc of the PPS resin is in the range of 160 to 190 ° C., so that stable stretch film formation is possible. Of course, if necessary, other polymer compounds, inorganic and organic compounds such as silicon oxide, magnesium oxide, calcium carbonate, titanium oxide, aluminum oxide, crosslinked polyester, crosslinked polystyrene, mica, talc and kaolin and thermal decomposition inhibitors, Heat stabilizers and antioxidants may be added.

  As a specific method for crosslinking / high molecular weight by heating PPS resin, under an oxidizing gas atmosphere such as air or oxygen or a mixed gas atmosphere of the oxidizing gas and an inert gas such as nitrogen or argon. A method of heating until a desired melt viscosity is obtained at a predetermined temperature in a heating container can be exemplified. The heat treatment temperature is usually selected from 170 to 280 ° C, more preferably from 200 to 270 ° C, and the heat treatment time is usually selected from 0.5 to 100 hours, more preferably from 2 to 50 hours. However, by controlling both of these, a target viscosity level can be obtained. The heat treatment apparatus may be a normal hot air dryer or a heating apparatus with a rotary type or a stirring blade, but in order to efficiently and uniformly perform the treatment, use a heating apparatus with a rotary type or a stirring blade. Is preferred.

  As a specific method for heat-treating the PPS resin under an inert gas atmosphere such as nitrogen or under reduced pressure, a heat treatment temperature of 150 to 280 ° C., preferably 200 to 200 ° C. under an inert gas atmosphere such as nitrogen or under reduced pressure. A method of heat treatment at 270 ° C. and a heating time of 0.5 to 100 hours, preferably 2 to 50 hours can be exemplified. The heat treatment apparatus may be a normal hot air drier or a heating apparatus with a rotary or stirring blade, but it is preferable to use a heating apparatus with a rotary or stirring blade for efficient and more uniform treatment. .

  The PPS resin used in the present invention is preferably a PPS resin that has been subjected to deionization treatment. Specific examples of the deionization treatment include an acid aqueous solution washing treatment, a hot water washing treatment, and an organic solvent washing treatment, and these treatments may be used in combination of two or more methods.

  The following method can be illustrated as a specific method for the organic solvent cleaning treatment of the PPS resin. That is, the organic solvent is not particularly limited as long as it does not have an action of decomposing the PPS resin. For example, nitrogen-containing polar solvents such as N-methylpyrrolidone, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, Sulfoxide / sulfone solvents such as dimethyl sulfone, ketone solvents such as acetone, methyl ethyl ketone, diethyl ketone, acetophenone, ether solvents such as dimethyl ether, dipropyl ether, tetrahydrofuran, chloroform, methylene chloride, trichloroethylene, ethylene chloride, dichloroethane, Halogen solvents such as tetrachloroethane, chlorobenzene, methanol, ethanol, propanol, butanol, pentanol, ethylene glycol, propylene glycol, Phenol, cresol, alcohol phenol based solvents such as polyethylene glycol, benzene, and aromatic hydrocarbon solvents such as toluene and xylene. Among these organic solvents, N-methylpyrrolidone, acetone, dimethylformamide and chloroform are particularly preferably used. These organic solvents are used alone or in combination of two or more.

  As a method of washing with an organic solvent, there is a method of immersing a PPS resin in an organic solvent, and it is possible to appropriately stir or heat as necessary. There is no restriction | limiting in particular about the washing | cleaning temperature at the time of wash | cleaning PPS resin with an organic solvent, Arbitrary temperature in the range of normal temperature-300 degreeC can be selected. As the cleaning temperature increases, the cleaning efficiency tends to increase, but usually a sufficient effect is obtained at a temperature of room temperature to 150 ° C. The PPS resin that has been washed with an organic solvent is preferably washed several times with water or warm water in order to remove the remaining organic solvent.

  The following method can be illustrated as a specific method of the hot water washing process of PPS resin. That is, it is preferable that the water to be used is distilled water or deionized water in order to exhibit a preferable chemical modification effect of the PPS resin by hot water washing. The operation of the hot water treatment is usually performed by adding a predetermined amount of PPS resin to a predetermined amount of water, and heating and stirring at normal pressure or in a pressure vessel. The ratio of the PPS resin to water is preferably larger, but usually a bath ratio of 200 g or less of PPS resin is selected for 1 liter of water.

  The following method can be illustrated as a specific method of the acid aqueous solution washing treatment of the PPS resin. That is, there is a method of immersing the PPS resin in an acid or an acid aqueous solution, and it is possible to appropriately stir or heat as necessary. The acid to be used is not particularly limited as long as it does not have an action of decomposing PPS resin. For example, aliphatic saturated monocarboxylic acids such as formic acid, acetic acid, propionic acid and butyric acid, and halogen-substituted fatty acids such as chloroacetic acid and dichloroacetic acid. Saturated carboxylic acids, aliphatic unsaturated monocarboxylic acids such as acrylic acid and crotonic acid, aromatic carboxylic acids such as benzoic acid and salicylic acid, dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, phthalic acid and fumaric acid And inorganic acidic compounds such as sulfuric acid, phosphoric acid, hydrochloric acid, carbonic acid and silicic acid. Of these, acetic acid and hydrochloric acid are preferably used. It is preferable to wash the acid-treated PPS resin several times with water or warm water in order to remove the remaining acid or salt. The water used for washing is preferably distilled water or deionized water in the sense that the effect of the preferred chemical modification of the PPS resin is not impaired by the acid treatment. When the acid aqueous solution cleaning treatment is performed, the acid terminal component of the PPS resin increases, and when mixed with polyester, polyimide, etc., the dispersibility is improved, and the thermal dimensional stability, heat resistance, and heat and humidity resistance of the hybrid resin are improved. Effect is obtained.

  The weight ratio c / b of the polyimide (b) and the polyarylene sulfide (c) contained in the biaxially oriented polyester film of the present invention is preferably 0.01 to 3.0, but the lower limit is preferably larger, 0.02 or more Preferably, it is 0.03 or more, more preferably 0.05 or more. Especially, it is very preferable to set it as the range of 0.1-3.0. More preferably, it is 0.3-2.0, and most preferably 0.5-1.5. Since the range of the weight ratio of the polyimide (b) and the polyarylene sulfide (c) is within the above range, the dispersion diameter of the polyimide (b) and the polyarylene sulfide (c) can be easily controlled within the range of the present invention. The film can be given excellent wet heat resistance, and at the same time, the production cost can be reduced.

  The compatibilizing agent (d) in the present invention acts as a compatibilizing agent for deriving a block copolymer composed of polyimide (b) and polyarylene sulfide (c).

  The raw material used when producing the biaxially oriented film of the present invention was prepared by kneading polyimide (b) and polyarylene sulfide (c) in advance using a compatibilizing agent (d) when producing a resin as a raw material. It is preferable to use a resin.

  In the present invention, by using the compatibilizing agent (d), excellent dispersibility in the film of the polyimide (b) and the polyarylene sulfide (c) in the film is obtained. Polyimide is easily dispersed in polyester, but polyarylene sulfide may not be sufficiently dispersed without a compatibilizer.

  When the biaxially oriented film of the present invention contains the compatibilizing agent (d), the average dispersed diameter of the dispersed phase in the polyarylene sulfide film can be easily controlled within the preferred range of the present invention. Such a compatibilizer (d) has at least one functional group selected from an epoxy group, amino group, isocyanate group, hydroxyl group, mercapto group and ureido group in the molecular formula and molecular structure of the compound. Compounds are preferred. These functional groups may selectively react with the polyimide (b) or polyarylene sulfide (c) in a high yield.

  The content of the compatibilizing agent (d) preferably contained in the present invention is 0.01 to 3 parts per 100 parts by weight of the total of the polyester (a), polyimide (b) and polyarylene sulfide (c) in the film. It is preferable that it is a weight part. More preferably, it is 0.1-2 weight part, Most preferably, it is 0.2-1.5 weight part.

  Examples of the compatibilizing agent (d) in the present invention include alkoxysilanes having one or more functional groups selected from an epoxy group, an amino group, and an isocyanate group. Specific examples of such compounds include epoxy group-containing alkoxysilanes such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, and β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane. Compounds, ureido group-containing alkoxysilane compounds such as γ-ureidopropyltriethoxysilane, γ-ureidopropyltrimethoxysilane, γ- (2-ureidoethyl) aminopropyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane Γ-isocyanatopropyltrimethoxysilane, γ-isocyanatopropylmethyldimethoxysilane, γ-isocyanatopropylmethyldiethoxysilane, γ-isocyanatopropylethyldimethoxysilane, γ-isocyanate pro Isocyanate group-containing alkoxysilane compounds such as ruethyldiethoxysilane, γ-isocyanate-propyltrichlorosilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ- (2-aminoethyl) aminopropyltri Examples include amino group-containing alkoxysilane compounds such as methoxysilane and γ-aminopropyltrimethoxysilane. Among these, an epoxy group-containing alkoxysilane compound and an isocyanate group-containing alkoxysilane compound are preferable because they easily react with polyimide and polyarylene sulfide. In particular, an isocyanate group-containing alkoxysilane is most preferred. Examples include γ-isocyanatopropyltriethoxysilane, γ-isocyanatopropyltrimethoxysilane, γ-isocyanatopropylmethyldimethoxysilane, γ-isocyanatopropylmethyldiethoxysilane, γ-isocyanate. Examples thereof include propylethyldimethoxysilane, γ-isocyanatopropylethyldiethoxysilane, and γ-isocyananetopropyltrichlorosilane.

  As a specific compatibilizer, for example, “KBE-9007” (product name) 3-isocyanatopropyltriethoxysilane, which is commercially available from Shin-Etsu Chemical Co., Ltd. and is available as a silane coupling agent, KBM-303 "(product name) 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane and the like.

  When an alkoxysilane having one or more functional groups selected from an epoxy group, an amino group, and an isocyanate group is used as a compatibilizing agent, a siloxane bond is formed between the polyetherimide (b) and the polyarylene sulfide (c). The siloxane bond is likely to exist near the interface of the dispersed phase. Silicon (silicon) atoms (elements) can be detected in the vicinity of the interface of the dispersed phase using a TEM-EDX method or the like. In the present invention, it is preferable that a silicon atom (Si) derived from a siloxane bond is included in the interface of the dispersed phase composed of polyimide (b) or polyarylene sulfide (c).

  In the resin phase separation structure observed with an electron microscope in the biaxially oriented film of the present invention, polyester forms a continuous phase, and polyimide and polyarylene sulfide form a dispersed phase.

  In the biaxially oriented film of the present invention, the average dispersion diameter of the polyimide (b) is required to be in the range of 1 to 50 nm, and the average dispersion diameter of the polyarylene sulfide (c) is required to be in the range of 50 to 500 nm. In order to make the average dispersion diameter of (b) and polyarylene sulfide (c) within the above range, it is preferable to contain a compatibilizing agent (d).

  When the biaxially oriented film of the present invention contains a compatibilizing agent, the polyimide (b) and the polyarylene sulfide (c) may each be able to form a dispersed phase satisfactorily. Specifically, the average dispersion diameter of polyimide (b) can be in the range of 1 to 50 nm, and the average dispersion diameter of polyarylene sulfide (c) can be in the range of 50 to 500 nm.

  It is virtually impossible for the average dispersion diameter of the polyimide (b) and the polyarylene sulfide (c) to be less than the above range. When it is at least the above range, the film-forming property is inferior, the film is inferior in mechanical strength, and the heat and moisture resistance is not sufficient.

  It is preferable that the average dispersion diameter of a polyimide (b) is 1-40 micrometers, More preferably, it is 2-40 nm, More preferably, it is 5-30 nm.

  The lower limit of the average dispersion diameter of the polyarylene sulfide (c) is preferably 50 nm or more, more preferably 70 nm or more, and further preferably 100 nm or more. On the other hand, the upper limit is preferably 400 nm or less, more preferably 300 nm or less, and still more preferably 200 nm or less. That is, the range of the average dispersion diameter of the polyarylene sulfide (c) is preferably 50 to 400 nm, and more preferably 70 to 300 nm.

  When the average dispersion diameter of the polyarylene sulfide (c) is within the above range, the polyarylene sulfide (c) functions effectively as a knot when stretching the film, and the film has excellent film formability, mechanical strength, and moisture resistance. In some cases, thermal properties and dielectric breakdown characteristics can be imparted.

  Here, the average dispersion diameter is an average equivalent circle diameter obtained on a plurality of observation surfaces.

  Regarding the dispersion diameter of the polyimide (b) and the polyarylene sulfide (c), first, the cut surface of the film was observed using a transmission electron microscope under the condition of an applied voltage of 100 kV, and a photograph was taken at 20,000 times. Next, the obtained photograph was taken into an image analyzer as an image, 100 arbitrary dispersed phases were selected, and image processing was performed as necessary to obtain a dispersion diameter.

  When the biaxially oriented film of the present invention is produced, the mixed resin (e), polyimide (b), polyarylene sulfide (c) and phase obtained by blending the polyester (a) and the polyimide (b) in advance. A mixed resin (f) obtained by blending the solubilizer (d) is prepared separately, and then a resin (g) obtained by further mixing the mixed resin (e) and the mixed resin (f) is prepared. It is preferable to produce a film using this mixed resin (g) as a raw material.

  However, when a resin (h) obtained by simply mixing a substance containing polyester (a), polyimide (b), polyarylene sulfide (c) and compatibilizer (d) at a time is used as a raw material, film formation At times, in melt extrusion, the intrinsic viscosity (IV) of a large film is reduced, and the heat and heat resistance of the film is reduced, or unmelted matter is generated in the film as coarse foreign matter, which may reduce the dielectric breakdown characteristics. It is not preferable. Moreover, compared with the film formed using this resin (h), the film manufactured using said mixed resin (g) has the outstanding film forming property, and provides very excellent heat-and-moisture resistance. be able to.

  In addition, the biaxially oriented film of the present invention may be a single layer or a laminated structure of at least two layers. When taking a laminated structure, the film layer of the present invention may be used as a base layer part or a laminated part, but at least one surface layer is preferably composed of the film layer of the present invention.

  Although the thickness of the biaxially oriented film of the present invention varies depending on applications, it is generally preferably in the range of 1 to 500 μm, more preferably 5 to 300 μm, and even more preferably 10 from the viewpoint of thin film use and workability. It is in the range of ~ 200 μm.

  In the biaxially oriented film of the present invention, the contained polyimide (b) and polyarylene sulfide (c) each form a dispersed phase, the average dispersion diameter of the polyimide (b) is 1 to 50 nm, and the polyarylene sulfide (c) When the average dispersion diameter is in the range of 50 to 500 nm, excellent dielectric breakdown characteristics can be imparted to the film.

  Furthermore, the biaxially oriented film of the present invention may be subjected to any processing such as heat treatment, molding, surface treatment, laminating, coating, printing, embossing and etching, as necessary.

The biaxially oriented film of the present invention has excellent wet heat resistance. As a method for defining the heat and moisture resistance, there is an elongation half-life by film elongation retention (defined by the following formula) before and after the moisture heat treatment.
Elongation retention (%) = (breaking elongation of sample after treatment) / (breaking elongation of sample before treatment)
The treatment time until the elongation retention reaches 50% is defined as the elongation half-life. The elongation half-life of the present invention is from 30 hours to 120 hours. The larger the half-life of the biaxially oriented film of the present invention in the heat and humidity resistance test, the less the film is likely to deteriorate under high temperature and high humidity. In the biaxially oriented film of the present invention, it is virtually impossible for the half-life of the heat and humidity resistance test test to exceed 120 hours. On the other hand, in the biaxially oriented film of the present invention, when the wet heat and heat test elongation half-life is 30 hours or less, the film may not substantially have wet heat resistance. The elongation half life is preferably 60 hours or longer.

  In order to obtain a biaxially oriented film having an elongation half-life of 30 to 120 hours in the wet heat resistance test, “polyetherimide (hereinafter abbreviated as“ PEI ”) (b)” and polyarylene sulfide (c) Is preferably dispersed in PET with an average dispersion diameter of 1 to 50 nm (PEI (b)) and 50 to 500 nm (polyarylene sulfide (c)) using a compatibilizing agent (d).

  Preferably, PPS is used for the polyarylene sulfide. In addition, it is preferable that the above-described more preferable compatibilizer is used to contain Si element derived from the siloxane bond at the dispersion interface as described above. The smaller the average dispersion diameter of PEI (b) and polyarylene sulfide (c) (or PPS when PPS is used for polyarylene sulfide (c)), the better the biaxially oriented film of the present invention is. The half-life of the heat and humidity resistance test of the biaxially oriented film of the present invention is preferably 65 hours or longer and 110 hours or shorter, more preferably 70 hours or longer and 100 hours or shorter.

  The biaxially oriented film of the present invention can impart excellent dielectric breakdown characteristics when the elongation half-life of the film by a heat and humidity test is 30 hours or more and 120 hours or less. A long life can be imparted to a member when used for a material application, for example, an electrical insulation application.

  When producing the biaxially oriented film of the present invention, a mixed resin (e), polyimide (b), polyarylene sulfide (c) and phase obtained by blending polyester (a) and polyimide (b) in advance. A mixed resin (f) obtained by blending the solubilizer (d) is prepared separately, and then a resin (g) obtained by further mixing the mixed resin (e) and the mixed resin (f) is prepared. Alternatively, a resin (g ′) in which polyester (a ′) is further kneaded with the mixed resin (f) is prepared. By producing a film using the mixed resin (g) as a raw material or using the mixed resin (g ′), the mixed resin (e) and the polyester (a) as a raw material, the film has a half-life of 30% or more for a half-life of heat and heat resistance test. Less than time can be achieved. More preferably, a mixed resin (g ′) is used.

  At this time, the melt viscosity [a '] of the polyester (a') is a resin satisfying the formula 1/3 <[a '] / [f] <3 between the melt viscosity [f] of the mixed resin (f). Preferably there is.

  The polyester (a) and the polyester (a ′) are preferably the same kind of polyester. When (a) and (a ′) are the same type, it may be possible to stably form a continuous film.

  In order to obtain the biaxially oriented film of the present invention, a resin (f) in which a polyimide (b), a polyarylene sulfide (c) and a compatibilizer (d) are kneaded is prepared, and then the resin (f) and the polyester (a It is important to use, as a film raw material, a mixed resin prepared by kneading twice according to the difference in resin processing temperature of kneading.

  The biaxially oriented film or sheet of the present invention preferably has no pores having polyarylene sulfide as a nucleus. By using the mixed resin prepared as described above as a raw material for the biaxially oriented film, pores having polyarylene sulfide as a nucleus are not generated in the film. Due to the absence of pores with polyarylene sulfide as the core, when the biaxially oriented film of the present invention is continuously formed by the melt film forming method, the film formation is stable and the productivity may be greatly improved. .

  Here, the “pores having polyarylene sulfide as a nucleus” in the present invention is a polyarylene sulfide in which the nucleus for pore formation represented by resin, particles, etc. that induces pore formation by stretching or the like. Defined as a hole. Such a pore having polyarylene sulfide as a nucleus is formed by the method described later. When an ultrathin section of a film is observed under a specific condition using a transmission electron microscope (TEM), the polyarylene sulfide is formed inside the hole. Observed as a nucleus. In contrast, in the present invention, pores that do not correspond to pores having polyarylene sulfide as a nucleus are polyarylene having a spherical shape, fibrous shape, irregular shape, or other shape inside the pores in the TEM observation image. It refers to pores where substances other than sulfide are observed as nuclei. The case where the pore itself is not observed in the observed image is included when there is no pore having polyarylene sulfide as a nucleus. In the present invention, “having no pores with polyarylene sulfide as a nucleus” means that, as shown in the following measurement method, in the TEM observation image, polyarylene sulfide is used with respect to the entire observation visual field area (total area of the film). This refers to the case where the ratio (R) of the total area of pores as nuclei is 10% or less. Under the present circumstances, even if it has a hole which makes polyarylene sulfide a nucleus, it may not be detected as a hole by the above-mentioned method, but if the ratio R calculated by this method is in the above range, the above effect (manufactured) (Productivity improvement due to film stabilization).

  The production of the mixed resins (e), (f), (g), and (g ′) will be described as a specific example in which polyethylene terephthalate is used as polyester, polyetherimide is used as polyimide, and polyphenylene sulfide is used as polyarylene sulfide.

  In the present invention, when the mixed resin (f) is produced from polyphenylene sulfide and polyetherimide, a method of kneading using a high shear mixer with a shear stress such as a twin screw extruder is preferable. In that case, it is preferable to prepare a mixed resin having a weight fraction of PPS and PEI of 99/1 to 70/30. In the case of mixing with a twin screw extruder, from the viewpoint of reducing poor dispersion, a screw equipped with a triple twin screw type or a double twin screw type is preferable. In the kneading part (kneading zone), the melting point of the PPS resin +5 A resin temperature range of ˜55 ° C. is preferred. A more preferable temperature range is the melting point of the PPS resin + 10 to 45 ° C., and a more preferable temperature range is the melting point of the PPS resin + 10 to 35 ° C. Setting the temperature range of the kneading part to a preferable range makes it easy to increase the shear stress and increases the effect of reducing defective dispersion, and the dispersed diameter of the dispersed phase can be controlled within the preferable range of the present invention.

  Moreover, the (retention) time of the whole kneading process at that time has the preferable range for 1 to 5 minutes.

  Moreover, it is preferable that screw rotation speed shall be 100-500 rotation / min, More preferably, it is the range of 200-400 rotation / min. By setting the screw rotation speed within the above range, high shear stress is easily added, and the dispersion diameter of the dispersed phase can be controlled within the preferred range of the present invention. The ratio of [screw shaft length / screw shaft diameter] of the twin screw extruder is preferably in the range of 20 to 60, and more preferably in the range of 30 to 50. Further, in the twin screw, it is preferable to provide a kneading part by a kneading paddle or the like in order to increase the kneading force, and the kneading part is preferably formed in a screw shape having two or more, more preferably three or more.

  The order of mixing the raw materials is not particularly limited, and a method in which all the raw materials are blended and melt-kneaded by the above method, a part of the raw materials are blended and then melt-kneaded by the above method, and the remaining raw materials are blended and melted. Any method may be used, such as a method of kneading, or a method of mixing a part of raw materials and mixing the remaining raw materials using a side feeder during melt-kneading with a single or twin screw extruder. Further, a method using a supercritical fluid described in Journal of Plastics Processing Society of Japan, “Molding”, Vol. 15, No. 6, pp. 382 to 385 (2003) can be preferably exemplified.

  In the present invention, in order to control the dispersion diameter of the PPS domain in PET, a compound having one or more groups selected from an epoxy group, an amino group and an isocyanate group is used as a compatibilizer (d). It is preferable to add 0.05 to 5 parts by weight with respect to 100 parts by weight in total of PPS. More preferably, 0.2 to 3 parts by weight is added, and still more preferably 0.3 to 2 parts by weight. When the added amount of the compatibilizing agent (d) is less than 0.05 parts by weight, the compatibility between PPS and PEI becomes poor, and the effects of the present invention may not be obtained. On the other hand, when the amount of the compatibilizing agent (d) exceeds 5 parts by weight, the reactivity between PPS and PEI is excessively increased, and the melt viscosity increases and it may be difficult to perform extrusion during film production.

  In the present invention, when alkoxysilane is used as the compatibilizing agent (d), alcohol derived from alkoxysilane may be generated during kneading or extrusion. In order to obtain a resin composition with a small amount of alcohol generated as a raw material for film formation, PPS, PEI and a compatibilizer were melt-kneaded using a twin screw extruder having two or more kneading parts. Later, a method of further melt-kneading at least once is mentioned as a preferred method. In addition, in the second and subsequent melt-kneading, it may be preferable to add 0.02 part or more, more preferably 0.1 to 5 parts of water with respect to 100 parts by weight of the total of PPS and PEI. By this method, hydrolysis of the alkoxysilane compound is promoted, and the amount of alcohol generated from the resulting resin composition can be reduced. It is preferable to remove as much as possible from the raw material chip for film formation obtained by kneading impurities and oligomers in PPS and PEI, alcohol generated from the reaction of the compatibilizing agent, etc. It is preferable to provide a vacuum vent after the kneading part (kneading zone) of the extruder during kneading. The method of adding water is not particularly limited, but a method of side-feeding water using a liquid feeding device such as a gear pump or a plunger pump from the middle of the extruder, or once melting and kneading and further melting once or more. When kneading, a preferable method is to mix water or side feed from the middle of the extruder.

  The raw material (resin composition) of the biaxially oriented film of the present invention is preferably thermally stable. Whether the raw material is thermally stable can be determined by the method described below.

  First, among the polyester (a), polyimide (b), and polyarylene sulfide (c) constituting the film, the melting point of the resin having the highest melting point is defined as Tm. Next, the average dispersed particle size of the polyimide (b) in the polyester (a) is preferably 0.1 to 50 nm for the dispersed phase in the resin composition which is melted and retained for 5 minutes at a temperature of Tm + 30 ° C. and cooled in a water bath. Is 1 to 30 nm, most preferably 2 to 15 nm, and the average dispersed particle size of the polyarylene sulfide (c) in the polyester (a) is 50 to 500 nm, preferably 80 to 300 nm, most preferably 100 to 200 nm. It is preferable that If it is in the said range, the said raw material is thermally stable. The upper limit of the average dispersed particle size of the polyimide (b) after 5 minutes of melt residence is 50 nm or less, more preferably 30 nm or more, most preferably 20 nm or less, and the lower limit is preferably 0.1 nm or more, more preferably 1 nm or more. Most preferably, it is 2 nm or more. The upper limit of the average dispersed particle size of the polyarylene sulfide (c) after 5 minutes of melt residence is preferably 500 nm or less, more preferably 300 nm or less, most preferably 200 nm or less, and the lower limit is preferably 50 nm or more, more preferably Is 80 nm or more, most preferably 100 nm or more. Since the raw material of the biaxially oriented film of the present invention has such thermal stability, the continuous film formation for a long time becomes stable, the productivity of the biaxially oriented film of the present invention is increased, and the cost is reduced. May be possible. Also, it may be easy to keep the film quality uniform.

  Next, polyethylene terephthalate (PET) as the polyester (a), polyetherimide (PEI) “Ultem” (registered trademark by GE Plastics) as the polyimide (b), and polyphenylene sulfide (PPS) as the polyarylene sulfide (c) The preferred method for producing the biaxially oriented film of the present invention will be described by exemplifying the case of using the present invention, but the present invention is not limited to the following production method.

  First, magnesium acetate is added to a mixture of dimethyl terephthalate and ethylene glycol, and the mixture is heated to raise the ester exchange reaction. Next, after adding trimethyl phosphate to the transesterification reaction product, germanium oxide is added to move to the polycondensation reaction layer. Next, the reaction system is gradually depressurized while being heated and heated, and the polymerization reaction proceeds at 290 ° C. under a reduced pressure of 1 mmHg or less. Here, polyester (PET) having an intrinsic viscosity of about 0.6 is obtained. In addition, as a method of incorporating the particles into the polyester constituting the film, a method of dispersing particles in ethylene glycol in a predetermined ratio in the form of a slurry, mixing the ethylene glycol slurry and the polyester, or adding them during the polyester manufacturing process. Is preferred.

  When adding the particles, for example, it is preferable to add the water sol or alcohol sol obtained at the time of synthesis without drying, since the dispersibility of the particles is good. It is also effective to mix the aqueous slurry of particles directly with predetermined polyester pellets and knead them into the polyester using a vented twin-screw kneading extruder. As a method for adjusting the content and number of particles, a master of high-concentration particles is prepared by the above-mentioned method, and it is diluted with a polyester that does not substantially contain particles during film formation to reduce the content of particles. The method of adjusting is effective.

  When mixing polyester, polyimide, and polyarylene sulfide, before melt extrusion, a method of pre-melting and kneading (pelletizing) a mixture of polyester, polyimide, polyimide, polyarylene sulfide, compatibilizer, and each resin into a master pellet Is preferably exemplified.

In the present invention, first, a vent type twin-screw kneading extruder in which the polyethylene terephthalate pellets and the polyetherimide pellets are mixed at a weight ratio of 20/80 to 80/20 and heated to 270 to 320 ° C. And melt extruded. The shear rate at this time is preferably 50 to 300 sec ⁻¹ , more preferably 100 to 200 sec ⁻¹ , and the residence time is preferably 0.5 to 10 minutes, more preferably 1 to 5 minutes. Furthermore, when not compatible under the above conditions, the obtained chip may be put into the twin-screw extruder again and extrusion may be repeated until compatible.

Meanwhile, the polyetherimide pellets, the polyphenylene sulfide pellets and the compatibilizer were mixed at a weight ratio of 20/80 / 0.001 to 80/20/3, and heated to 300 to 330 ° C. To the two-screw kneading extruder. The shear rate at this time is preferably 50 to 300 sec ⁻¹ , more preferably 100 to 200 sec ⁻¹ , and the residence time is preferably 0.5 to 10 minutes, more preferably 1 to 5 minutes. It is preferable to obtain a sufficiently dispersed state. When the average dispersion diameter of the polyimide (b) in the obtained master pellet is 50 nm or more or the average dispersion diameter of the polyarylene sulfide (c) is larger than 500 nm, the master pellet is again put into the twin screw extruder. Extrusion may be repeated until the dispersion average particle size of is within the range of the present invention.

  Next, the obtained pellets made of polyester and polyetherimide (corresponding to the mixed resin (e)), and pellets made of polyetherimide, polyphenylene sulfide and a compatibilizer (corresponding to the mixed resin (f)) ) And polyethylene terephthalate pellets for dilution (polyester (a)) were dried under reduced pressure at 150 to 180 ° C. for 3 hours or more and then heated to 270 to 320 ° C. under a nitrogen stream or under reduced pressure so as not to lower the intrinsic viscosity. A biaxially oriented film is produced by feeding to an extruder.

  Moreover, it is preferable to use various types of filters, for example, filters made of materials such as sintered metal, porous ceramics, sand, and wire mesh, in order to remove foreign substances and denatured polymers. Moreover, you may provide a gear pump as needed in order to improve fixed_quantity | feed_rate supply property. Using an extruder, a sheet of a mixture of molten polyester, polyetherimide, and polyphenylene sulfide is extruded from a slit die and cooled on a casting roll to produce an unstretched film.

  According to the purpose, the resin constituting the biaxially oriented polyester film of the present invention includes a flame retardant, a heat stabilizer, a weathering material, an antioxidant, an ultraviolet absorber, a light stabilizer, a rust inhibitor, and a copper-resistant damage. Various additives such as stabilizers, antistatic agents, pigments, plasticizers, endblockers, lubricants, organic lubricants, chlorine scavengers, antiblocking agents, viscosity modifiers, and the like are added within a range that does not impair the purpose of the present invention. It doesn't matter.

Examples of the antioxidant include 2,6-di-tert-butyl-p-cresol (BHT); 3,3 ′, 3 ″, 5,5 ′, 5 ″ -hexa-tert-butyl-a, a ′, a ″-(mesitylene-2,4,6-triyl) tri-p-cresol (for example, IRGANOX 1330 manufactured by Ciba Specialty Chemicals);
Examples include pentaerythrole tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (for example, IRGANOX 1010 manufactured by Ciba Specialty Chemicals Co., Ltd.).

Examples of the heat stabilizer include tris (2,4-di-tert-butylphenyl) phosphite (for example, IRGAFOS168 manufactured by Ciba Specialty Chemicals);
Examples include a reaction product of 3-hydroxy-5,7-di-tert-butyl-furan-2-one and o-xylene (for example, HP-136 manufactured by Ciba Specialty Chemicals Co., Ltd.).
However, antioxidants and heat stabilizers are not limited to the above examples.

  The addition amount of the antioxidant and the heat stabilizer is 0.03 to 1 part by weight with respect to 100 parts by weight of the total of the polyester (a), polyimide (b), and polyarylene sulfide (c) of the film. Preferably there is. When the addition amount of each of the antioxidant and the heat stabilizer is less than the above range, it is inferior in long-term heat resistance and heat-and-moisture resistance in the production process until the biaxially oriented polyester film is obtained from the initial raw material, and in the subsequent secondary processing process. There is a case. In addition, when the addition amount of each of the antioxidant and the heat stabilizer exceeds the above range, the long-term heat resistance and heat-and-moisture resistance of the biaxially oriented polyester film obtained even if added more than that range, the economy is inferior There is. The addition amount of each of the antioxidant and the heat stabilizer is more preferably 0.05 to 0.00 with respect to 100 parts by weight of the total of the polyester (a), polyimide (b) and polyarylene sulfide (c) in the film. 9 parts by weight, more preferably 0.1 to 0.8 parts by weight.

  In the biaxially oriented film of the present invention, other components such as an organic lubricant such as an ultraviolet absorber, an antistatic agent, a flame retardant, a pigment, a dye, a fatty acid ester, and a wax are added within a range that does not impair the effects of the present invention. May be. In addition, inorganic particles, organic particles, and the like can be added to impart easy slipping, abrasion resistance, scratch resistance, and the like to the film surface.

  Examples of such additives include clay, mica, titanium oxide, calcium carbonate, kaolin, talc, wet or dry silica, colloidal silica, calcium phosphate, barium sulfate, alumina, zirconia, and other inorganic particles, acrylic acids, styrene And so-called internal particles, surfactants, and the like which are precipitated by a catalyst added during the polymerization reaction of polyester or polyphenylene sulfide.

Although the thickness of the biaxially oriented polyester film of this invention is not specifically limited, 1000 micrometers or less are preferable, More preferably, it is the range of 0.5-500 micrometers. Although it can be appropriately determined according to the application and purpose as described later, the range of 0.5 to 20 μm is particularly preferable.
The film of the present invention is suitably used for a magnetic recording medium, and is particularly suitable for a high density magnetic recording tape, for example, a base film for data storage. When used for magnetic recording media, the thickness of the film is usually 1 to 15 μm for magnetic recording materials, 2 to 10 μm for coated magnetic recording media for data or digital video, and vapor deposition for data or digital video. For the type magnetic recording medium, a range of 3 to 9 μm is preferable.

  The film of the present invention is also suitably used for capacitors, and the film thickness in this case is preferably 0.5 to 15 μm. By setting the film thickness within such a range, the dielectric breakdown voltage and the stability of the dielectric characteristics are excellent.

  Moreover, the film of this invention is used suitably also for a thermal transfer ribbon use, and it is preferable that the film thickness in this case is 1-6 micrometers. By setting the film thickness within such a range, high-definition printing can be performed without wrinkling during printing and without causing printing unevenness and ink overtransfer.

  The film of the present invention is also suitably used for heat-sensitive stencil paper, and the film thickness in this case is preferably 0.5 to 5 μm. By making the film thickness within such a range, the punching ability at low energy is also excellent, the punching diameter can be changed according to the energy level, and the printing property when performing color printing with multiple plates, etc. It is also excellent.

  The biaxially oriented film of the present invention preferably has an internal haze of 0 to 50%. More preferably, it is 0-30%, More preferably, it is 0-20%, Most preferably, it is 0-10%.

  When the internal haze is in the above range, there are cases in which the use of the biaxially oriented film of the present invention can be widened. For example, when the internal haze is within the above range, the biaxially oriented film or sheet of the present invention having high heat resistance and hydrolysis resistance may be used as a display member.

  In the method for producing a biaxially oriented polyester film of the present invention, a sheet-like product is formed by discharging from a die by melt extrusion using an extruder and cooling and solidifying the molten polymer.

  Next, the obtained sheet-like material is stretched in the longitudinal direction (longitudinal direction), then stretched in the width direction (transverse direction), or stretched in the width direction (transverse direction) and then stretched in the longitudinal direction (longitudinal direction). Biaxial orientation is imparted to the film by the sequential biaxial stretching method or the simultaneous biaxial stretching method. Although the specific example by the sequential biaxial stretching method used most generally is shown below, this invention is not limited to the following description.

  First, the sheet-like material (unstretched film) heated by a plurality of roll groups is not less than the glass transition temperature of the polyester (a) and not more than the glass transition temperature of the polyarylene sulfide (c), for example, at a stretching temperature of 90 to 170 ° C. The film is stretched in the longitudinal direction (longitudinal direction) in one step or in two or more steps at a magnification of 2 to 5 times, preferably 2.5 to 4.5 times, more preferably 3 to 4 times, and uniaxial An oriented film (uniaxially stretched film) is obtained.

  Furthermore, the film is gripped with a clip and guided to a tenter, which is not less than the glass transition temperature of the polyester (a) and not more than the glass transition temperature of the polyarylene sulfide (c), for example, a stretching temperature of 90 to 180 ° C., and a magnification of 2 to 6 times. The film is preferably stretched in the width direction (lateral direction) at a magnification of 2.5 to 5.5 times, more preferably 3 to 4.5 times. Under the present circumstances, you may extend | stretch 1.01-2.5 times further at the temperature of 110-180 degreeC in the longitudinal direction and / or the width direction as needed.

  In the present invention, the heat treatment temperature after stretching is preferably a temperature equal to or lower than the melting point of the polyester (a), more preferably a temperature of 190 to 245 ° C., and still more preferably, from the viewpoints of dimensional stability, heat resistance, and moist heat resistance. Is a temperature of 200 to 230 ° C. and is preferably heat-treated for 1 to 30 seconds. In addition, the biaxially oriented film of the present invention is preferably subjected to an intermediate cooling of 100 to 160 ° C. after the heat treatment step from the viewpoint of easily obtaining toughness, preferably a relaxation treatment, and in the width direction and / or the longitudinal direction. The relaxation treatment is preferably performed at a rate of 2 to 10%, more preferably 4 to 9%.

In this way, a biaxially oriented film (biaxially stretched film) excellent in heat and moisture resistance can be obtained.
A specific example in the case of producing a film used for a magnetic recording medium, for example, when the simultaneous biaxial stretching method is used is shown below.

  Simultaneous biaxial stretching can be performed by a simultaneous biaxial stretching method in which stretching is performed simultaneously in the longitudinal direction and the width direction using a simultaneous biaxial tenter. The stretching temperature varies depending on the structural component of the polyester and the component of the laminated portion when it is a laminated film, but in a single layer, the polyester (a) is polyethylene terephthalate, the polyimide (b) is polyetherimide, and the polyarylene sulfide. The case where polyphenylene sulfide is used as (c) will be described as an example. An unstretched film is guided to a linear motor type simultaneous biaxially stretched tenter by holding both ends of the film with clips, and in the preheating zone, the glass transition temperature of polyethylene terephthalate is not lower than the glass transition temperature of polyphenylene sulfide, for example, 85 to It is heated to 90 ° C., and stretched in one or two or more stages 4.5 to 10 times simultaneously in both the longitudinal direction and the width direction. The draw ratio may be different between the longitudinal direction and the width direction. At this time, it is preferable that the temperature of the clip holding the film edge is not less than the glass transition temperature of PET and not more than the glass transition temperature of PET + 30 ° C. The stretching temperature in the stretching step is preferably kept within the temperature range of not less than the glass transition temperature of the polyester (a) and not more than the glass transition temperature of the polyarylene sulfide (c), but once cooled, the film is crystallized. It may be stretched while being suppressed. In the case of a raw material having a high molecular weight or a material that is difficult to crystallize, it is preferable that the stretching temperature is increased to 200 ° C. In the latter half of the stretching process, it is preferable to stretch the film while gradually increasing the stretching temperature in two or more stages.

  Subsequently, from the viewpoint of manifestation of the effects of the present invention, the biaxially stretched film has a melting point of PET of −70 ° C. or higher and a melting point of PET or lower, more preferably a melting point of PET of −50 ° C. or higher and a melting point of PET of −10 ° C. or lower. The heat setting process is performed in the range of.

  Furthermore, a limited shrinkage of 0.5 to 5%, more preferably 1 to 3% is given in the longitudinal and width directions at the above heat setting temperature (hereinafter referred to as relaxation heat treatment I), and then the glass transition of the PET in the cooling process. More than temperature, melting point of PET-50 ° C. or less, more preferably glass transition temperature of PET + 10 ° C. or more, melting point of PET−80 ° C. or less, 1-7% with respect to longitudinal and width directions, more preferably 2 A limited shrinkage is given in a range of ˜6% (hereinafter referred to as relaxation heat treatment II). Here, the limited shrinkage is to suppress free shrinkage of the film by gripping the film edge with a clip during heat treatment (heat setting). That is, heat treatment (heat setting) is performed while restricting the shrinkage of the film.

  The relaxation heat treatment may be performed with different limiting shrinkage rates in the longitudinal direction and the width direction. In particular, it is preferable to perform relaxation heat treatment II in the cooling process after performing relaxation heat treatment I at the heat setting temperature in order to further enhance the effects of the present invention. The relaxation heat treatment II is preferably performed in two or more stages by changing the temperature. Then, the target biaxially oriented polyester film is obtained by cooling the film to room temperature, removing the film edge and winding up.

  The glass transition temperature Tg as used in the field of this invention is a value calculated | required according to JIS-K7121 from the heat flux gap at the time of temperature rising in a differential scanning calorimetry. When it is difficult to make a determination only by a method based on differential scanning calorimetry, a morphological method such as dynamic viscoelasticity measurement or microscopic observation may be used in combination. When determining the glass transition temperature by differential scanning calorimetry, it is also effective to use a temperature modulation method or a high sensitivity method. The melting point Tm in the present invention is a value determined according to JIS-K7122.

[Measurement method of physical properties]
(1) The measurement film of the content of each resin in the film is weighed and then dissolved in hexafluoroisopropanol (HFIP). When polyarylene sulfide is contained, it is insoluble, so the insoluble component is collected by centrifugation, and then weighed. The structure and weight fraction of polyarylene sulfide are measured by elemental analysis, FT-IR, and NMR methods. Can be measured. If the supernatant component is similarly analyzed, the weight fraction and structure of the polyester component and the polyimide component can be specified. Specifically, an NMR spectrum of ¹ H nucleus is measured for this supernatant component. In the obtained spectrum, the peak area intensity of absorption specific to polyester and polyimide (for example, aromatic proton of terephthalic acid if polyester is polyethylene terephthalate, aromatic proton of bisphenol A if polyimide is polyetherimide) The molar ratio of the blend is calculated from the ratio and the number of protons. Further, the weight ratio is calculated from the formula amount corresponding to the unit unit of the polymer. In this way, the weight fraction and structure of the polyester component and the polyimide component can be specified.

(2) A detection film of Si atoms (Si element) in the dispersed interface phase was cut in a direction parallel to the longitudinal direction and perpendicular to the film surface, and a sample was prepared by an ultrathin section method. In order to clarify the contrast of the dispersed phase, it may be stained with osmic acid, ruthenic acid, phosphotungstic acid, or the like. Using a field emission electron microscope (JEOL JEM2100F, EDX (JEOL JED-2300T)), the cut surface was subjected to a pressurization voltage of 200 kV, a sample absorption current of 10 ⁻⁹ A, an EDX ray analysis of 20 seconds / point, and a beam diameter of 1 nm. The interface of the dispersed phase was evaluated by the TEM-EDX method under the conditions described above. Arbitrary evaluation was made on 10 dispersed phases, and the case where Si element was detected by 0.2 atomic% or more was indicated as ◯, and the case where it was not possible was indicated as X.

(3) The average dispersion diameter film of the dispersed phase is (a) a direction parallel to the longitudinal direction and perpendicular to the film surface, (a) a direction parallel to the width direction and perpendicular to the film surface, and (c) parallel to the film surface. The sample was cut in various directions, and a sample was prepared by an ultrathin section method. In order to clarify the contrast of the dispersed phase, it may be stained with osmic acid, ruthenic acid, phosphotungstic acid, or the like. The cut surface was observed using a transmission electron microscope (H-7100FA type, manufactured by Hitachi) under the condition of an applied voltage of 100 kV, and a photograph was taken at 20,000 times. The obtained photograph is taken into an image analyzer as an image, 100 arbitrary dispersed phases are selected, and image processing is performed as necessary, thereby obtaining the size of the dispersed phase as shown below. It was. The maximum thickness (la) and the maximum length (lb) in the film thickness direction of each dispersed phase appearing on the cut surface of (a), and the maximum thickness (lb) in the longitudinal direction of each dispersed phase appearing on the cut surface of (a) The maximum length (lc), the maximum length (ld) in the width direction, the maximum length (le) in the film longitudinal direction and the maximum length (lf) in the width direction of each dispersed phase appearing on the cut surface of (c). Asked. Next, the shape index I of the dispersed phase I = (number average value of lb + number average value of le) / 2, shape index J = (number average value of ld + number average value of lf) / 2, shape index K = (of la Number average value + number average value of lc) / 2, the average dispersion diameter of the dispersed phase was (I + J + K) / 3. Further, from I, J, and K, the maximum value was determined as the average major axis L, and the minimum value was determined as the average minor axis D.

(4) Intrinsic viscosity (IV)
Dissolve the sample in orthochlorophenol. The portion that does not dissolve is removed, and the portion that dissolves is measured. The value calculated by the following equation from the solution viscosity measured at 25 ° C. in orthochlorophenol was used.
ηsp / C = [η] + K [η] ² · C
Where ηsp = (solution viscosity / solvent viscosity) −1, C is the weight of dissolved polymer per 100 ml of solvent (g / 100 ml, usually 1.2), K is the Huggins constant (assuming 0.343), [η] Is the intrinsic viscosity (unit: dL / g) of the polymer (sample). Further, the solution viscosity and the solvent viscosity were measured using an Ostwald viscometer.

(5) Film thickness The film thickness was measured at 30 g of needle pressure using an electronic micrometer (K-312A type) manufactured by Anritsu Co., Ltd. in an atmosphere of 23 ° C. and 65% RH.

(6) Breaking strength and breaking elongation Measured using an Instron type tensile tester according to the method defined in JIS K7127. The measurement was performed under the following conditions, and the sample was changed 20 times. The average value was obtained by measuring each sample.

Measuring device: Orientec Co., Ltd. film strong elongation automatic measuring device "Tensilon AMF / RTA-100"
Sample size: width 10 mm x test length 200 mm (in the film longitudinal direction)
Sample shape: Strip pulling speed: 300 m / min Measurement environment: temperature 25 ° C., humidity 65% RH.
The distance between the initial pull chucks is 100 mm.
(7) Orientation discrimination The orientation state of the film is discriminated from an X-ray diffraction photograph obtained when X-rays are incident on the film from the following three directions.
・ Through incidence: Incident perpendicular to the surface formed in the longitudinal direction (MD) and transverse direction (TD) of the film. ・ End incidence: Incident perpendicular to the surface formed in the lateral direction and thickness direction of the film. ・ Edge incidence: Incident perpendicular to the surface formed in the longitudinal and thickness directions of the film.
In addition, the sample aligned the direction, piled up so that thickness might be set to about 1 mm, cut out, and used for the measurement.

X-ray diffraction photographs were measured by the imaging plate method under the following conditions.
・ X-ray generator: 4036A2 type manufactured by Rigaku Corporation ・ X-ray source: CuKα ray (using Ni filter)
・ Output: 40kV, 20mA
・ Slit system: 1mmφ pinhole collimator ・ Imaging plate: FUJIFILM BAS-SR
Imaging conditions: camera radius (distance between sample and imaging plate) 40 mm, exposure time 5 minutes.

Here, the non-orientation, uniaxial orientation, and biaxial orientation of the film are described in, for example, Kiyoichi Matsumoto et al., “Journal of Textile Society”, Vol. 26, No. 12, 1970, p. 537-549; Kiyoichi Matsumoto, “Making a film”, Kyoritsu Shuppan (1993), p. 67-86; Seizo Okamura et al., “Introduction to Polymer Chemistry (2nd Edition)”, Kagaku Dojin (1981), p. As described in 92-93, etc., it can be determined according to the following criteria.
・ Non-orientation: Debye with a substantially uniform intensity in X-ray diffraction photographs in any direction. ・ A (vertical) uniaxial orientation: Debye with substantially uniform intensity in an X-ray diffraction photograph of end incidence. -A Scherrer ring is obtained-Biaxial orientation: A diffraction image in which the diffraction intensity is not uniform is reflected in the X-ray diffraction photograph in any direction, reflecting the orientation.

(8) Moist heat resistance (half time of elongation at break)
A strip-shaped sample having a length of 200 mm and a width of 10 mm was cut out and used in the longitudinal direction of the film. In accordance with the method defined in JIS K-7127, the elongation at break was measured at 25 ° C. and 65% RH using a tensile tester. The distance between the initial pull chucks was 100 mm, and the pull speed was 300 m / min. The measurement was performed 20 times by changing the sample, and the average value (X) of the elongation at break was determined. In addition, in the longitudinal direction of the film, a strip-shaped sample having a length of 200 mm and a width of 10 mm was applied under a pressure of ² kg / cm ² using a highly accelerated life tester (Presser Cooker TPC-211 type manufactured by Tabay Espec Co., Ltd.) The sample was allowed to stand in an atmosphere of 140 ° C. and 80% RH and then naturally cooled. The sample was subjected to a tensile test under the same conditions as described above 20 times, and an average value (Y) of the breaking elongation was obtained. From the average values (X) and (Y) of the obtained elongation at break, the elongation retention was determined by the following equation. The treatment time until the elongation retention was 50% or less was defined as the half time of elongation at break.
Elongation retention (%) = (Y / X) × 100
The heat treatment time until the elongation retention was 50% or less was defined as the half-life of elongation at break. Wet heat resistance was evaluated according to the following criteria. ◎, ○, and Δ are acceptable, but a longer half-life is more preferable.
A: Elongation half-life is 80 hours or more.
○: The elongation half-life is 60 hours or more and less than 80 hours.
Δ: The elongation half-life is 30 hours or more and less than 60 hours.
X: The elongation half-life is less than 30 hours.

(9) Dielectric breakdown characteristics A 100-μm-thick 10 cm square aluminum foil electrode is used for the cathode, a brass 25 mmφ, 500-g electrode is used for the anode, a film is sandwiched between them, and a voltage increase rate of 100 V / sec using a Kasuga high-voltage DC power supply When a current of 10 mA or more flows, the dielectric breakdown is assumed, and the voltage value at this time is measured. 200V / μ or more was rated as ◯, and less than 200V / μ was rated as x.

(10) Internal haze of film Measured using a haze meter (HZ-2 manufactured by Suga Test Instruments Co., Ltd.) based on JIS K 7105 (1985). Moreover, the internal haze except a film surface haze was measured by putting the film in the quartz cell for liquid measurement, filling with liquid paraffin, and performing the measurement.

(11) Melt viscosity of polymer Measured using a flow tester CFT-500A (high and low flow tester) manufactured by Shimadzu Corporation. Load after 3 minutes of preheating time, KP (proportional constant) 40, integral time constant (I-TIME) 70, differential time constant (D-TIME) 70, die size 1mm, die length 10mm, plunger cut The area is 1 cm ² and the measurement is performed at a measurement position of 7 mm to 10 mm. The measurement was performed 5 times, and the average value was taken as the melt viscosity of the polymer. The unit of melt viscosity is [Pa · s]. In addition, although the shear rate at the time of measurement varies depending on the resin to be measured, the specific shear rate is as described above.

(12) Young's modulus Measured using an Instron type tensile tester according to the method defined in ASTM-D882. The measurement was performed under the following conditions.
Measuring device: Orientec Co., Ltd. film strong elongation automatic measuring device "Tensilon AMF / RTA-100"
Sample size: width 10 mm x test length 100 mm,
Tensile speed: 200 mm / min Measurement environment: temperature 23 ° C., humidity 65% RH
(13) Glass transition temperature (Tg)
It measured by the pseudo isothermal method according to JIS-K7121.
Measuring device: Temperature modulation DSC manufactured by TA Instrument
Heating temperature: 0 ° C to 300 ° C (RCS cooling method)
Temperature calibration: Melting point temperature modulation amplitude of high purity indium and tin: ± 1 ° C
Temperature modulation period: 60 seconds Temperature rising step: 5 ° C
Sample mass: 5mg
Sample container: Aluminum open container (22 mg)
Reference container: Aluminum open container (18mg)
The glass transition temperature (Tg) was calculated by the following formula.
Glass transition temperature = (extrapolated glass transition start temperature + extrapolated glass transition end temperature) / 2
(14) Melting point (Tm)
The peak temperature of the endothermic peak of melting was measured according to JIS-K7122 as the melting point (Tm).
Measuring device: “Robot DSC-RDC220” manufactured by Seiko Electronics Industry Co., Ltd.
For data analysis, “Disk Session SSC / 5200” was used.
Sample mass: 5 mg
Sample pretreatment: After melting and holding at 300 ° C for 5 minutes, rapid solidification heating rate: 20 ° C / min
(15) Confirmation that pores having polyarylene sulfide as a nucleus do not exist In order to confirm the absence of pores having a polyarylene sulfide as a nucleus, the following method was used.
An ultrathin slice having a cross section in the transverse direction-thickness direction of the biaxially oriented film or sheet of the present invention or polyester film composite was collected by an ultramicrotome by a resin embedding method using an epoxy resin. The section of the collected slice was observed using a transmission electron microscope (TEM) under the following conditions. Sample preparation and cross-sectional observation were performed at Toray Research Center.
・ Device: Transmission electron microscope (TEM) H-7100FA manufactured by Hitachi, Ltd.
・ Acceleration voltage: 100kV
Observation magnification: 40,000 times With respect to the biaxially oriented film or sheet of the present invention, a photograph is collected in which a side of the photograph is continuously observed parallel to the lateral direction of the film and parallel to the thickness direction. At this time, the size of one side parallel to the horizontal direction and one side parallel to the thickness direction in each photo was adjusted to be 6 μm and 5 μm, respectively, in the actual size of the film, and 10 μm (for two photos) parallel to the thickness direction. Equivalent). In addition, when the thickness of the film or sheet is less than 10 μm, a photograph observed continuously in parallel in the lateral direction may be collected.

An OHP sheet (an OSON sheet dedicated to EPSON manufactured by Seiko Epson Corporation) was placed on the obtained images. Next, of the observed voids, if there were observed nuclei inside the holes, only the nuclei were painted black on the OHP sheet with a magic pen. An image of the obtained OHP sheet was read under the following conditions.
Here, in order to discriminate that the nucleus is polyarylene sulfide (c), the portion serving as the core of the hole is examined using a field emission electron microscope (JEM2100F manufactured by JEOL, EDX (JED-2300T manufactured by JEOL)). The nuclei of the holes are evaluated by the TEM-EDX method under the conditions of an applied voltage of 200 kV, a sample absorption current of 10 ⁻⁹ A, an EDX ray analysis of 20 seconds / point, and a beam diameter of 1 nm. Arbitrary evaluation of 10 nuclei, S element detected more than 0.5 atomic%, nuclei composed of polyarylene sulfide, S element detected 0 to 0.5 atomic%, other than polyarylene sulfide A core consisting of
・ Scanner: Seiko Epson GT-7600U
・ Software: EPSON TWAIN ver. 4.20J
・ Image type: Line drawing ・ Resolution: 600dpi
The obtained image was subjected to image analysis using Image-Pro Plus, Ver.40 for Windows (registered trademark) manufactured by Planetron Co., Ltd. At this time, spatial calibration was performed using the scale of the captured cross-sectional image. The measurement conditions were set as follows.
-Fill the outline format in the display option settings in the count / size option.
-Set the object extraction option to None on the boundary.
・ Automatic extraction of dark objects for the brightness range selection setting during measurement.

Under the above conditions, the total area of the film, that is, the horizontal direction × thickness direction = 5 μm ×
The ratio of the area of pores (black-filled portion) with polyarylene sulfide (c) as the nucleus to the film thickness (measured in (5) above) was calculated as a percentage, and the area ratio (R) of the pores ( unit:%). From this, when the ratio of the pores having polyarylene sulfide as a nucleus to the total area of the film was 0% or more and 30% or less, the film was defined as having no pores having polyarylene sulfide as a nucleus.
The case where the ratio of the pores having polyarylene sulfide as the core to the total area of the film is 0% or more and less than 3% ◎, the case where it is 3% or more and less than 5%, ○, the case where it is 5% or more and 10% or less Δ. Moreover, since the film with the said ratio R larger than 10% has the hole which makes polyarylene sulfide a nucleus, it was set as x.

The obtained image was transferred to Image-Pro Plus, Ver. 4.0
Image analysis was performed using for Windows (registered trademark). At this time, spatial calibration was performed using 20 scales of the captured cross-sectional image. The measurement conditions were set as follows.
-Fill the outline format in the display option settings in the count / size option.
-In the object extraction option settings, set the exclusion on the boundary to None.
・ Automatic extraction of dark objects for the brightness range selection setting during measurement.
Under the above-mentioned conditions, the ratio of the area of the core (blackened portion) to the total area of the film observed with a photograph, that is, the horizontal direction × thickness direction = 5 μm × 10 μm as a measurement target was calculated as a percentage. The same measurement was performed three times for the same sample while changing the observation position, and the average value of the obtained area ratios was defined as the area ratio (R TEM) of the nucleus of the sample (unit:%). From this, when the ratio of the nucleus to the total area of the film is 5% or less, the film is defined as 30 having no-nuclear holes, and is marked as ◯. Moreover, since the film where the said ratio RTEM exceeds 5% does not have a nucleusless hole, it was set as x.

(15) Film formation stability A biaxially oriented polyester film was formed so that the width direction was 5 m, and the number of tears of the film until 10,000 m was wound was determined. In addition, film formation stability was evaluated from the number of film breaks as follows.
A: When there was no film tearing.
○: When the film was torn once or twice.
Δ: When the film was broken 3 or 4 times.
X: When the film was broken 5 times or more.

  The present invention will be described based on examples.

(Reference Example 1)
Production of polyethylene terephthalate (PET) polymer chips:
To a mixture of 100 parts by weight of dimethyl terephthalate and 60 parts by weight of ethylene glycol, 0.04 part by weight of magnesium acetate was added to 100 parts by weight of dimethyl terephthalate, and the mixture was heated to increase the ester exchange reaction.

  Next, 0.020 parts by weight of trimethyl phosphate is added to 100 parts by weight of dimethyl terephthalate, 0.02 parts by weight of germanium oxide is added to the transesterification product, and then the polycondensation reaction tank is transferred. did.

  Subsequently, the reaction system was gradually depressurized while being heated and heated, and polymerization was performed at 290 ° C. under a reduced pressure of 1 mmHg or less, thereby obtaining a polyethylene terephthalate chip having an intrinsic viscosity [η] = 0.65.

  Reference Example 2 Production of polyethylene-2,6-naphthalate (PEN) polymer chip: To a mixture of 100 parts by weight of dimethyl 2,6-naphthalenedicarboxylate and 60 parts by weight of ethylene glycol, manganese acetate tetrahydrate salt 0 0.03 part by weight was added, and the ester exchange reaction was carried out while gradually raising the temperature from 150 ° C to 240 ° C. In the middle, when the reaction temperature reached 170 ° C., 0.024 parts by weight of antimony trioxide was added. When the reaction temperature reached 220 ° C., 0.042 parts by weight (corresponding to 2 mmol%) of 3,5-dicarboxybenzenesulfonic acid tetrabutylphosphonium salt was added. Thereafter, a transesterification reaction was carried out. After the transesterification reaction, 0.023 parts by weight of trimethyl phosphate was added. Next, the reaction product was transferred to a polymerization reactor, heated to a temperature of 290 ° C., and subjected to a polycondensation reaction under a high vacuum of 0.2 mmHg or less, and polyethylene-2,6 having an intrinsic viscosity of 0.65 dl / g. -A naphthalate chip was obtained.

(Reference Example 3)
Production of polyimide (c-1, c-2) polymer chip:
<Polyimide (c-1)>
200 g of isophorone diisocyanate was added to 3,000 ml of N-methyl-2-pyrrolidone (NMP) under a nitrogen atmosphere and stirred. Next, 196 g of pyromellitic anhydride was added to this solution at room temperature, and then the temperature was gradually raised. Thereafter, heating at 180 ° C. for 6 hours stopped generation of carbon dioxide, so heating was stopped. After this polymer solution was developed and washed in water, the polymer obtained here was dried to obtain polyimide (c-1).

<Polyimide (c-2)>
Under a nitrogen stream, 147 g (0.5 mol) of biphenyltetracarboxylic dianhydride was added to 300 g of N-methyl-2-pyrrolidone. A solution obtained by dissolving 57 g (0.5 mol) of trans-1,4-diaminocyclohexane in 17.6 g of NMP was added dropwise to this solution, followed by stirring at room temperature for 2 hours and further at 50 ° C. for 4 hours to obtain a polyamic acid solution. This solution was cooled and then poured into 500 ml of water to precipitate a polymer. The precipitated polymer was collected by filtration and heat-treated at 250 ° C. for 2 hours in nitrogen to obtain the target polyimide (c-2).

Example 1
After 50 parts by weight of polyethylene terephthalate (PET) having an intrinsic viscosity of 0.65 obtained in Reference Example 1 and 50 parts by weight of polyetherimide (PEI) “Ultem” manufactured by General Electric, dehumidified and dried at 150 ° C. for 5 hours. , Heated to 320-290 ° C (screw zone, setting temperature gradient at extrusion head), twin-screw, three-stage type screw (PET and PEI kneading plasticization zone / Dalmage kneading zone / inverted screw Dalmage to achieve fine dispersion compatibilization PET with 50% by weight of PEI supplied to a vent type twin screw extruder (L / D = 40, vent hole pressure reduced to 200 Pa) and melt extruded in a residence time of 3 minutes. / PEI blend chip was obtained. This chip was designated as blend chip A.

  Furthermore, 10 parts by weight of polyetherimide (PEI) “Ultem” 1010 manufactured by General Electric, linear PPS resin (“Torelina” (registered trademark) M2088 manufactured by Toray Industries, Inc.), glass transition temperature 92 ° C., melting point 283 ° C.) and 90 parts by weight of γ-isocyanatopropyltriethoxysilane “KBE9007” manufactured by Shin-Etsu Chemical Co., Ltd. as a compatibilizer were heated to 320 to 290 ° C. (screw zone, extrusion Vent twin screw extruder (L / P) equipped with twin-screw three-stage type screw (PEI and PPS kneading plasticization zone / Dalmage kneading zone / inverted screw dullage compatibilizing zone) D = 40, the pressure reduction degree of the vent hole was 200 Pa), melt extrusion with a residence time of 3 minutes, and PPS A PEI / PPS / compatibilizer blend chip containing 90% by weight of resin was obtained. Further, a mixture of 100 parts by weight of the obtained PEI / PPS / compatibility agent and 0.5 parts by weight of water was melt-extruded by a twin screw extruder heated to 320 to 290 ° C. The obtained pellet was used as a blend chip B.

  Next, 30 parts by weight of blend chip B and 70 parts by weight of PET were supplied to a twin screw extruder heated to 270 to 310 ° C. and melt-extruded to obtain a blend chip of PET / PEI / PPS / compatibilizer. The resulting blend chip was designated as blend chip C.

  Next, 17.9 parts by weight of the obtained PET / PEI blend chip A and 17.8 parts by weight of the PET / PEI / PPS / compatibilizer blend chip C and the PET chip having an intrinsic viscosity of 0.65 obtained in Reference Example 1 64. 3 parts by weight are mixed so as to have the content (% by weight) shown in the table, dried under reduced pressure at 180 ° C. for 3 hours, put into an extruder, melt extruded at 300 ° C., and a fiber sintered stainless steel metal filter After passing (14 μm cut), the sheet was discharged from a T-die, and the sheet was adhered and solidified by a static electricity application method on a cooling drum having a surface temperature of 25 ° C. to obtain an unstretched film.

  Subsequently, the unstretched film was stretched by a factor of 3.4 times in the longitudinal direction of the film at a temperature of 95 ° C. using a peripheral speed difference of the roll using a heated longitudinal stretching machine composed of a plurality of roll groups. And stretched. Thereafter, both ends of the film were gripped with clips, led to a tenter, stretched 3.8 times at a temperature of 100 ° C. in the width direction, and subsequently heat treated at a temperature of 210 ° C. for 3 seconds (in the width direction). 2% relaxation treatment), followed by further 2% relaxation treatment in the width direction at a temperature zone of 150 ° C., and then gradually cooled to room temperature to obtain a biaxially oriented film having a thickness of 100 μm. The characteristics of the obtained biaxially oriented film are shown in the table. The biaxially oriented film obtained in this example was excellent in heat and moisture resistance. It also showed excellent dielectric breakdown characteristics.

(Examples 2 to 4)
In Example 2, biaxial orientation was carried out in the same manner as in Example 1 except that the film was stretched at 90 ° C. in both the machine direction and the transverse direction, and the content of the compatibilizing agent constituting the film was changed to the conditions shown in the table. A film was prepared. About Examples 3-4, the biaxially oriented film was created like Example 1 except having changed the content of the compatibilizing agent which comprises a film into the conditions shown in the table | surface. In particular, a biaxially oriented film was obtained by using blend chips A to C as in Example 1. The characteristics of the obtained biaxially oriented film are shown in the table. The biaxially oriented films obtained in Examples 2 to 4 were excellent in heat and moisture resistance. It also showed excellent dielectric breakdown characteristics.

(Example 5)
A biaxially oriented film was prepared in the same manner as in Example 1 except that 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane “KBM303” manufactured by Shin-Etsu Chemical Co., Ltd. was used as a compatibilizing agent. The characteristics of the obtained biaxially oriented film are shown in the table. The obtained biaxially oriented film was excellent in heat and moisture resistance. It also showed excellent dielectric breakdown characteristics.

(Example 6)
A biaxially oriented film was prepared in the same manner as in Example 1 except that the content of the polymer constituting the film was changed to the conditions shown in the table. In particular, as in Example 1, blend chips A to C were used. In Example 6, 4.3 parts by weight of blend chip A, 81.5 parts by weight of blend chip C, and 14.2 parts by weight of PET chip having an intrinsic viscosity of 0.65 obtained in Reference Example 1 are shown in the table. It mixed so that it might become quantity (weight%). The characteristics of the obtained biaxially oriented film are shown in the table. The biaxially oriented film obtained in Example 6 was excellent in heat and moisture resistance. It also showed excellent dielectric breakdown characteristics.

(Example 7)
A biaxially oriented film was prepared in the same manner as in Example 1 except that the content of the polymer constituting the film was changed to the conditions shown in the table. In particular, as in Example 1, blend chips A to C were used. In Example 7, 26.2 parts by weight of the blend chip A, 16.7 parts by weight of the blend chip C, and 56.8 parts by weight of the PET chip having an intrinsic viscosity of 0.65 obtained in Reference Example 1 are shown in the table. It mixed so that it might become quantity (weight%). The characteristics of the obtained biaxially oriented film are shown in the table. The biaxially oriented film obtained in Example 7 was excellent in heat and moisture resistance. It also showed excellent dielectric breakdown characteristics.

(Example 8)
A biaxially oriented film was prepared in the same manner as in Example 1 except that the content of the polymer constituting the film was changed to the conditions shown in the table. In particular, as in Example 1, blend chips A to C were used. In Example 8, 33.8 parts by weight of the blend chip A, 15.9 parts by weight of the blend chip C, and 50.2 parts by weight of the PET chip having an intrinsic viscosity of 0.65 obtained in Reference Example 1 are shown in the table. It mixed so that it might become quantity (weight%). The characteristics of the obtained biaxially oriented film are shown in the table. The biaxially oriented film obtained in Example 8 was excellent in heat and moisture resistance. It also showed excellent dielectric breakdown characteristics.

Example 9
A biaxially oriented film was prepared in the same manner as in Example 1 except that the content of the polymer constituting the film was changed to the conditions shown in the table. In particular, as in Example 1, blend chips A to C were used. In Example 9, 19.5 parts by weight of blend chip A, 5.6 parts by weight of blend chip C, and 74.9 parts by weight of PET chip having an intrinsic viscosity of 0.65 obtained in Reference Example 1 are shown in the table. It mixed so that it might become quantity (weight%). The characteristics of the obtained biaxially oriented film are shown in the table. The biaxially oriented film obtained in Example 9 was excellent in wet heat resistance. It also showed excellent dielectric breakdown characteristics.

(Example 10)
A biaxially oriented film was prepared in the same manner as in Example 1 except that the content of the polymer constituting the film was changed to the conditions shown in the table. In particular, as in Example 1, blend chips A to C were used. In Example 10, 13.6 parts by weight of blend chip A, 56.6 parts by weight of blend chip C, and 29.7 parts by weight of PET chip having an intrinsic viscosity of 0.65 obtained in Reference Example 1 are shown in the table. It mixed so that it might become quantity (weight%). The characteristics of the obtained biaxially oriented film are shown in the table. The biaxially oriented film obtained in Example 10 was excellent in heat and moisture resistance. It also showed excellent dielectric breakdown characteristics.

(Example 11)
A biaxially oriented film was prepared in the same manner as in Example 1 except that the content of the polymer constituting the film was changed to the conditions shown in the table. In particular, as in Example 1, blend chips A to C were used. In Example 11, 11.2 parts by weight of blend chip A, 76.3 parts by weight of blend chip C, and 12.5 parts by weight of PET chips having an intrinsic viscosity of 0.65 obtained in Reference Example 1 are shown in the table. It mixed so that it might become quantity (weight%). The characteristics of the obtained biaxially oriented film are shown in the table. The biaxially oriented film obtained in Example 11 was excellent in heat and moisture resistance. It also showed excellent dielectric breakdown characteristics.

(Examples 12 and 13)
A biaxially oriented film having a thickness of 100 μm was obtained in the same manner as in Example 1 except that the polyimide (c-1, c-2) shown in Reference Example 3 was used as the polyimide (c). It was set as Examples 12 and 13, respectively. The characteristics of the obtained films are shown in the table. The biaxially oriented films obtained in Examples 12 and 13 were excellent in heat and moisture resistance. It also showed excellent dielectric breakdown characteristics.

(Example 14)
Implemented except that a linear PPS resin ("Torelina" (registered trademark) M3910, glass transition temperature 90 ° C, melting point 283 ° C (b-1)) manufactured by Toray Industries, Inc. was used as the polyarylene sulfide (b). A film was formed in the same manner as in Example 1 to obtain a biaxially oriented film having a thickness of 100 μm. The properties of the obtained film are shown in the table. The biaxially oriented film obtained in this example was excellent in heat and moisture resistance. It also showed excellent dielectric breakdown characteristics.

(Example 15)
50 parts by weight of polyethylene-2,6-naphthalenedicarboxylate (PEN) having an intrinsic viscosity of 0.60 obtained in Reference Example 2 and 50 parts by weight of polyetherimide (PEI) “Ultem” 1010 manufactured by General Electric, Dehumidified and dried at 175 ° C. for 5 hours, then heated to 320 to 290 ° C. (screw zone, temperature gradient set at extrusion head), twin-screw, three-stage screw (PET and PEI kneading plasticization zone / Dalmage kneading Supplyed to a vent type twin screw extruder (L / D = 40, vent hole pressure reduced to 200 Pa) equipped with a zone / a fine dispersion compatibilization zone by reverse screw damage), and melt extrusion with a residence time of 3 minutes A PEN / PEI blend chip containing 50% by weight of PEI was obtained. This chip was designated as blend chip D.

  Furthermore, 10 parts by weight of polyetherimide (PEI) “Ultem” 1010 manufactured by General Electric, linear PPS resin (“Torelina” (registered trademark) M2088 manufactured by Toray Industries, Inc.), glass transition temperature 92 ° C., melting point 283 ° C.) and 90 parts by weight of γ-isocyanatopropyltriethoxysilane “KBE9007” manufactured by Shin-Etsu Chemical Co., Ltd. as a compatibilizer were heated to 320 to 290 ° C. (screw zone, extrusion Vent twin screw extruder (L / P) equipped with twin-screw three-stage type screw (PEI and PPS kneading plasticization zone / Dalmage kneading zone / inverted screw dullage compatibilizing zone) D = 40, the pressure reduction degree of the vent hole was 200 Pa), melt extrusion with a residence time of 3 minutes, and PPS A PEI / PPS / compatibilizer blend chip containing 90% by weight of resin was obtained. Further, a mixture of 100 parts by weight of the obtained PEI / PPS / compatibilizer and 0.5 parts by weight of water was melt-extruded by a twin screw extruder heated to 320 to 290 ° C. The obtained pellet was used as a blend chip B.

  Next, 30 parts by weight of blend chip B and 70 parts by weight of PEN were supplied to a twin-screw extruder heated to 270 to 310 ° C., and melt-extruded to obtain a PEN / PEI / PPS / compatibilizer blend chip. The obtained blend chip was named blend chip E.

  Next, 17.9 parts by weight of the obtained PEN / PEI blend chip D and 17.8 parts by weight of PEN / PEI / PPS / compatibilizer blend chip E and the PEN chip having an intrinsic viscosity of 0.60 obtained in Reference Example 2 64. 3 parts by weight are mixed so as to have the content (% by weight) shown in the table, dried under reduced pressure at 175 ° C. for 5 hours, put into an extruder, melt extruded at 300 ° C., and a fiber sintered stainless steel metal filter After passing (14 μm cut), the sheet was discharged from a T-die, and the sheet was adhered and solidified by an electrostatic application method on a cooling drum having a surface temperature of 55 ° C. to obtain an unstretched film.

  Subsequently, the unstretched film was stretched by 4.0 times in the longitudinal direction of the film at a temperature of 140 ° C. using a difference in peripheral speed of the roll by using a longitudinal stretching machine composed of a plurality of heated roll groups. And stretched. Thereafter, both ends of this film are gripped with clips, guided to a tenter, stretched 5.0 times at a temperature of 140 ° C. in the width direction, and subsequently heat treated at a temperature of 250 ° C. for 10 seconds, and then brought to room temperature. Slow cooling was performed to obtain a biaxially oriented film having a thickness of 250 μm. The characteristics of the obtained biaxially oriented film are shown in the table. The biaxially oriented film obtained in this example was excellent in heat and moisture resistance. It also showed excellent dielectric breakdown characteristics.

(Comparative Example 1)
The polyethylene terephthalate (PET) having an intrinsic viscosity of 0.65 obtained in Reference Example 1 was dried under reduced pressure at 180 ° C. for 3 hours, then charged into an extruder, melt extruded at 285 ° C., and a fiber sintered stainless steel metal filter. After passing (14 μm cut), the sheet was discharged from a T-die, and the sheet was adhered and solidified by a static electricity application method on a cooling drum having a surface temperature of 25 ° C. to obtain an unstretched film.

  Subsequently, the unstretched film was stretched by a factor of 3.4 in the longitudinal direction of the film at a temperature of 105 ° C. using a difference in peripheral speed of the roll using a longitudinal stretching machine composed of a plurality of heated roll groups. And stretched. Thereafter, both ends of the film were gripped with clips, guided to a tenter, stretched 3.7 times at a temperature of 110 ° C. in the width direction, and subsequently heat treated at a temperature of 210 ° C. for 3 seconds, and then 170 ° C. In the temperature zone, 3% relaxation treatment was further performed in the width direction, followed by slow cooling to room temperature to obtain a biaxially oriented film having a thickness of 100 μm. The characteristics of the obtained biaxially oriented film are shown in the table. The obtained biaxially oriented film was inferior in wet heat resistance.

(Comparative Example 2)
50 parts by weight of polyethylene terephthalate (PET) having the intrinsic viscosity of 0.65 obtained in Reference Example 1 and 50 parts by weight of polyetherimide (PEI) “Ultem” 1010 manufactured by General Electric Co., at 150 ° C. for 5 hours. Dehumidified and dried, then heated to 320 to 290 ° C (screw zone, temperature gradient set at extrusion head), twin-screw, three-stage type screw (PET and PEI kneading plasticization zone / Dalmage kneading zone / reverse screw dalmage Supplied to a vent type twin screw extruder (L / D = 40, vent hole pressure reduced to 200 Pa) equipped with a fine dispersion compatibilization zone), melt extruded with a residence time of 3 minutes, and 50 wt. % PET / PEI blend chip was obtained.

  Next, the obtained PET / PEI blend chip and the above-mentioned PET chip having an intrinsic viscosity of 0.65 were mixed so as to have the content (% by weight) shown in the table, dried at 180 ° C. under reduced pressure for 3 hours, and then extruded. It was put into a machine, melt extruded at 285 ° C., passed through a fiber sintered stainless steel filter (14 μm cut), then discharged from a T die into a sheet, and the sheet was statically placed on a cooling drum having a surface temperature of 25 ° C. An unstretched film was obtained by solidifying and solidifying with an electric application method.

  Subsequently, the unstretched film was stretched by a factor of 3.4 in the longitudinal direction of the film at a temperature of 105 ° C. using a difference in peripheral speed of the roll using a longitudinal stretching machine composed of a plurality of heated roll groups. And stretched. Thereafter, both ends of the film were gripped with clips, guided to a tenter, stretched 3.7 times at a temperature of 110 ° C. in the width direction, and subsequently heat treated at a temperature of 210 ° C. for 3 seconds, and then 170 ° C. In the temperature zone, 3% relaxation treatment was further performed in the width direction, followed by slow cooling to room temperature to obtain a biaxially oriented film having a thickness of 100 μm. The characteristics of the obtained biaxially oriented film are shown in the table. The biaxially oriented film obtained in this comparative example containing no polyarylene sulfide (c) was inferior in heat and moisture resistance.

(Comparative Example 3)
A PET / PPS blend chip and a PET chip with an intrinsic viscosity of 0.65 were mixed so as to have the content (% by weight) shown in the table, dried under reduced pressure at 180 ° C. for 3 hours, and then charged into an extruder. After melt extrusion at 300 ° C. and passing through a fiber sintered stainless metal filter (14 μm cut), the sheet is discharged from a T-die into a sheet shape, and the sheet is adhered to a cooling drum having a surface temperature of 25 ° C. by an electrostatic application method. Solidified and cooled to obtain an unstretched film.

  Subsequently, the unstretched film was stretched by 4.0 times in the longitudinal direction of the film at a temperature of 90 ° C. using a peripheral speed difference of the roll using a longitudinal stretching machine composed of a plurality of heated roll groups. And stretched. Thereafter, both ends of this film are gripped with clips, guided to a tenter, stretched 4.0 times in the width direction at a temperature of 90 ° C., and subsequently heat treated at a temperature of 180 ° C. for 3 seconds, and then brought to room temperature. The film was slowly cooled to obtain a biaxially oriented film having a thickness of 100 μm. The characteristics of the obtained biaxially oriented film are shown in the table. The biaxially oriented film obtained in this comparative example containing no polyimide (b) was inferior in heat and moisture resistance.

(Comparative Example 4)
50 parts by weight of polyethylene terephthalate (PET) having the intrinsic viscosity of 0.65 obtained in Reference Example 1 and 50 parts by weight of polyetherimide (PEI) “Ultem” 1010 manufactured by General Electric Co., at 150 ° C. for 5 hours. After drying, heated to 320-290 ° C (screw zone, temperature gradient is set at the extrusion head), twin-screw, three-stage type screw (PET and PEI kneading plasticization zone / Dalmerization kneading zone / reverse screw The mixture was supplied to a vent type twin screw extruder (L / D = 40, the degree of pressure reduction of the vent hole was 200 Pa) equipped with a dispersion compatibilization zone), melt-extruded in a residence time of 3 minutes, and 50% by weight of PEI. The contained PET / PEI blend chip was obtained.

  Further, 50 parts by weight of a linear PPS resin (“Torelina” (registered trademark) M2088, glass transition temperature 92 ° C., melting point 283 ° C.) manufactured by Toray Industries, Inc., with an intrinsic viscosity of 0.65 obtained in Reference Example 1 50 parts by weight of PET was dried under reduced pressure at 180 ° C. for 3 hours, and then heated to 320 to 290 ° C. (temperature gradient was set in the screw zone and extrusion head). Feed time to a bent type twin screw extruder (L / D = 40, the degree of pressure reduction of the vent hole is 200 Pa) equipped with a crystallization zone / dalmage kneading zone / inverted screw dalmage). To obtain a PET / PPS blend chip containing 50 wt% PPS resin.

  Subsequently, the obtained PET / PEI blend chip, the PET / PPS blend chip, and the PET chip having the intrinsic viscosity of 0.65 were mixed so as to have the content (% by weight) shown in the table, and then at 180 ° C. for 3 hours. After drying under reduced pressure, it is put into an extruder, melt-extruded at 300 ° C., passed through a fiber sintered stainless steel metal filter (14 μm cut), and then discharged into a sheet form from a T-die. On the cooling drum, it was solidified by an electrostatic application method and cooled to obtain an unstretched film.

  Subsequently, the unstretched film was stretched by a factor of 3.4 times in the longitudinal direction of the film at a temperature of 95 ° C. using a peripheral speed difference of the roll using a heated longitudinal stretching machine composed of a plurality of roll groups. And stretched. Thereafter, both ends of the film were gripped with clips, led to a tenter, stretched 3.8 times at a temperature of 100 ° C. in the width direction, and subsequently heat treated at a temperature of 210 ° C. for 3 seconds (in the width direction). 2% relaxation treatment), followed by further 2% relaxation treatment in the width direction at a temperature zone of 150 ° C., and then gradually cooled to room temperature to obtain a biaxially oriented film having a thickness of 100 μm. The characteristics of the obtained biaxially oriented film are shown in the table. The biaxially oriented film obtained in this example was inferior in heat resistance.

(Comparative Example 5)
50 parts by weight of polyethylene terephthalate (PET) having the intrinsic viscosity of 0.65 obtained in Reference Example 1 and 50 parts by weight of polyetherimide (PEI) “Ultem” 1010 manufactured by General Electric Co., at 150 ° C. for 5 hours. After drying, heated to 320-290 ° C (screw zone, temperature gradient is set at the extrusion head), twin-screw, three-stage type screw (PET and PEI kneading plasticization zone / Dalmerization kneading zone / reverse screw The mixture was supplied to a vent type twin screw extruder (L / D = 40, the degree of pressure reduction of the vent hole was 200 Pa) equipped with a dispersion compatibilization zone), melt-extruded in a residence time of 3 minutes, and 50% by weight of PEI. The contained PET / PEI blend chip was obtained.

  Further, 50 parts by weight of a linear PPS resin (“Torelina” (registered trademark) M2088, glass transition temperature 92 ° C., melting point 283 ° C.) manufactured by Toray Industries, Inc., with an intrinsic viscosity of 0.65 obtained in Reference Example 1 As a compatibilizing agent, 0.5 part by weight of γ-isocyanatopropyltriethoxysilane “KBE9007” manufactured by Shin-Etsu Chemical Co., Ltd. was heated to 320 to 290 ° C. (screw zone, extrusion head part) Vent type twin-screw extruder (L / D =) equipped with a twin-screw three-stage type screw (PET and PPS kneading plasticization zone / dull image kneading zone / fine dispersion compatibilization zone by reverse screw dull mage) 40, the pressure reduction degree of the vent hole was 200 Pa), melt extrusion with a residence time of 3 minutes, and a PET / PPS blend containing 50% by weight of PPS resin. It was obtained Dochippu.

  Subsequently, the obtained PET / PEI blend chip, the PET / PPS blend chip, and the PET chip having the intrinsic viscosity of 0.65 were mixed so as to have the content (% by weight) shown in the table, and then at 180 ° C. for 3 hours. After drying under reduced pressure, it is put into an extruder, melt-extruded at 300 ° C., passed through a fiber sintered stainless steel metal filter (14 μm cut), and then discharged into a sheet form from a T-die. On the cooling drum, it was solidified by an electrostatic application method and cooled to obtain an unstretched film.

  Subsequently, the unstretched film was stretched by a factor of 3.4 times in the longitudinal direction of the film at a temperature of 95 ° C. using a peripheral speed difference of the roll using a heated longitudinal stretching machine composed of a plurality of roll groups. And stretched. Thereafter, both ends of the film were gripped with clips, led to a tenter, stretched 3.8 times at a temperature of 100 ° C. in the width direction, and subsequently heat treated at a temperature of 210 ° C. for 3 seconds (in the width direction). 2% relaxation treatment), followed by further 2% relaxation treatment in the width direction at a temperature zone of 150 ° C., and then gradually cooled to room temperature to obtain a biaxially oriented film having a thickness of 100 μm. The characteristics of the obtained biaxially oriented film are shown in the table. The biaxially oriented film obtained in this example was inferior in heat resistance.

(Comparative Example 6)
90 parts by weight of polyethylene terephthalate (PET) having an intrinsic viscosity of 0.65 obtained in Reference Example 1, 10 parts by weight of polyetherimide (PEI) “Ultem” 1010 manufactured by General Electric, and 5 parts by weight of PPS resin at 180 ° C. And then dried under reduced pressure for 3 hours, put into an extruder, melt extruded at 300 ° C., passed through a fiber sintered stainless steel metal filter (14 μm cut), and then discharged from a T-die into a sheet shape. An unstretched film was obtained by solidifying and cooling on a cooling drum having a temperature of 25 ° C. by electrostatic application.

  Subsequently, the unstretched film was stretched by a factor of 3.4 times in the longitudinal direction of the film at a temperature of 95 ° C. using a peripheral speed difference of the roll using a heated longitudinal stretching machine composed of a plurality of roll groups. And stretched. Thereafter, both ends of the film were gripped with clips, led to a tenter, stretched 3.8 times at a temperature of 100 ° C. in the width direction, and subsequently heat treated at a temperature of 210 ° C. for 3 seconds (in the width direction). 2% relaxation treatment), followed by further 2% relaxation treatment in the width direction at a temperature zone of 150 ° C., and then gradually cooled to room temperature to obtain a biaxially oriented film having a thickness of 100 μm. Film formation was not stable and a biaxially oriented film was not obtained.

(Comparative Example 7)
80% by weight of polyethylene terephthalate resin having a melting point of 260 ° C., an intrinsic viscosity of 1.27, and a carboxyl end group amount of 14 eq / t, a melting point of 280 ° C., an ash content of 0.6% by weight, a melt viscosity of 40 Pa · s, and a chloroform extraction amount of 3. 10% by weight of PPS resin 8%, MFR = 1000 g / 10 min, “Ultem 1010” polyetherimide resin manufactured by GE Plastics, 10% by weight, epoxy equivalent 875-975, molecular weight 1600 bisphenol A type epoxy resin After dry blending at a ratio of 1% by weight, it was melt-kneaded with a TEX30 twin-screw extruder manufactured by Nippon Steel Works, and pelletized with a strand cutter. The pellets dehumidified and dried at 120 ° C. overnight are put into an extruder, melt extruded at 300 ° C., passed through a fiber sintered stainless steel metal filter (14 μm cut), and then discharged from a T die into a sheet shape. Was solidified and cooled by electrostatic application on a cooling drum having a surface temperature of 25 ° C. to obtain an unstretched film.

  Subsequently, the unstretched film was stretched by a factor of 3.4 times in the longitudinal direction of the film at a temperature of 95 ° C. using a peripheral speed difference of the roll using a heated longitudinal stretching machine composed of a plurality of roll groups. And stretched. Thereafter, both ends of the film were gripped with clips, led to a tenter, stretched 3.8 times at a temperature of 100 ° C. in the width direction, and subsequently heat treated at a temperature of 210 ° C. for 3 seconds (in the width direction). 2% relaxation treatment), followed by further 2% relaxation treatment in the width direction at a temperature zone of 150 ° C., and then gradually cooled to room temperature to obtain a biaxially oriented film having a thickness of 100 μm. The characteristics of the obtained biaxially oriented film are shown in the table. The biaxially oriented film obtained in this example was inferior in heat-and-moisture resistance and inferior in dielectric breakdown characteristics.

Reference Example 4 Poly-p-phenylene sulfide (PPS-1) polymerization in a 70 liter autoclave equipped with a stirrer was a 47.5 mass% aqueous solution of sodium hydrosulfide 8,267.37 g (70.00 mol), 96 2,957.21 g (70.97 mol) of an aqueous solution of sodium hydroxide in mass%, 11,434.50 g (115.50 mol) of N-methyl-2-pyrrolidone (NMP), 2,583.00 g of sodium acetate (31 , 50 mol), and 10,500 g of ion-exchanged water, and gradually heated to 245 ° C. over about 3 hours while passing nitrogen at normal pressure, and after distilling 14,780.1 g of water and 280 g of NMP, the reaction vessel Was cooled to 160 ° C. The amount of water remaining in the system per mole of the charged alkali metal sulfide was 1.06 mol including the water consumed for the hydrolysis of NMP. The amount of hydrogen sulfide scattered was 0.02 mol per mol of the charged alkali metal sulfide.

  Next, 10,235.46 g (69.63 mol) of p-dichlorobenzene and 9,09.0.00 g (91.00 mol) of NMP were added, the reaction vessel was sealed under nitrogen gas, and the mixture was stirred at 240 rpm. The temperature was raised to 238 ° C. at a rate of 6 ° C./min. After reacting at 238 ° C. for 95 minutes, the temperature was raised to 270 ° C. at a rate of 0.8 ° C./min. After reacting at 270 ° C. for 100 minutes, 1,260 g (70 mol) of water was injected over 15 minutes and cooled to 250 ° C. at a rate of 1.3 ° C./minute. Then, after cooling to 200 ° C. at a rate of 1.0 ° C./min, it was rapidly cooled to near room temperature.

  The contents were taken out, diluted with 26,300 g of NMP, the solvent and solid matter were filtered off with a sieve (80 mesh), and the resulting particles were washed with 31,900 g of NMP and filtered off. This was washed 3 times with 56,000 g of ion-exchanged water and filtered, and then washed with 70,000 g of 0.05 wt% acetic acid aqueous solution and filtered. After washing with 70,000 g of ion-exchanged water and filtering, the resulting hydrous PPS particles were dried with hot air at 80 ° C. and dried under reduced pressure at 120 ° C. The obtained PPS had a melt viscosity of 200 Pa · s (310 ° C., shear rate of 1,000 / s), a glass transition temperature of 93 ° C., and a melting point of 285 ° C.

(Example 16)
The PPS-1 resin prepared in Reference Example 4 was dried under reduced pressure of 1 mmHg at 180 ° C for 3 hours, and polyetherimide (“Ultem 1010” manufactured by GE Plastics) as polyimide (b) at 120 ° C for 3 hours at 1 mmHg Were dried separately under reduced pressure.

  After mixing 50 parts by weight of the above PPS-1 resin and 50 parts by weight of PEI with 2.4 parts by weight of γ-isocyanatopropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., “KBE9007”) under dry air, kneading paddle Charged into a co-rotating twin-screw kneading and extruding machine (manufactured by Nippon Steel Works, screw diameter 30 mm, screw length / screw diameter = 45.5) with three vacuum kneading sections, residence time 90 seconds, screw rotation speed It was melt-extruded at 300 rpm at 330 ° C., discharged into a strand, cooled with water at a temperature of 25 ° C., and immediately cut to produce a blend chip. The obtained PPS / PEI (50/50 parts by weight) blended chip raw material with 0.3 parts by weight of water added per 100 parts by weight was charged into the above twin-screw kneading extruder, residence time 90 seconds, screw A PEI / PPS blend chip was produced by melt extrusion at 330 ° C., 330 ° C., and discharging into a strand, cooling with water at a temperature of 25 ° C., and immediately cutting.

  The obtained PEI / PPS blend chip and the polyethylene terephthalate (PET) having an intrinsic viscosity of 0.65 obtained in Reference Example 1 were separately dried under reduced pressure of 1 mmHg at 180 ° C. for 3 hours. After drying, 30 parts by weight of PEI / PPS blend chip and 70 parts by weight of PET are put into the above-mentioned twin-screw kneader / extruder, melt residence time is 90 seconds, screw speed is 300 revolutions / minute, and it is melt extruded at 300 ° C and discharged into a strand. After cooling with water at a temperature of 25 ° C., it was immediately cut to prepare a PET / PEI / PPS blend chip.

  The obtained PET / PEI / PPS blend chip, the PET obtained in Reference Example 1 and the PET / PEI blend chip A prepared in Example 1 have the weight fraction of each resin in the film as shown in the table. Then, each chip was supplied to a full flight single screw extruder whose melting part was heated to 295 ° C.

  Next, the polymer melted by the extruder is filtered through a filter set at a temperature of 300 ° C., melt-extruded from a die of a T die set at a temperature of 300 ° C., and then adhered while applying an electrostatic charge to a cast drum having a surface temperature of 25 ° C. After cooling and solidification, an unstretched PET / PEI / PPS mixed film was produced.

  This unstretched PET / PEI / PPS film is stretched 3 times in the longitudinal direction of the film at a stretching temperature of 89 ° C. using a difference in the peripheral speed of the roll by using a longitudinal stretching machine composed of a plurality of heated roll groups. The film was stretched at a magnification of 4 times. Thereafter, both ends of the film were gripped with clips, led to a tenter, stretched 3.8 times in the width direction at a temperature of 89 ° C., and subsequently heat treated at a temperature of 210 ° C. for 3 seconds (in the width direction). 2% relaxation treatment), followed by further 2% relaxation treatment in the width direction in a temperature zone of 150 ° C., and then slowly cooled to room temperature to obtain a biaxially oriented film having a thickness of 30 μm. The characteristics of the obtained biaxially oriented film are shown in the table. The biaxially oriented film obtained in this example was excellent in heat and moisture resistance. It also showed excellent dielectric breakdown characteristics.

(Example 17)
An unstretched PET / PEI / PPS film was produced in the same manner as in Example 16 except that the contents of the resin constituting the film and the compatibilizing agent were changed to the conditions shown in the table.

  Grip both ends of this unstretched film with clips and lead to a linear motor type simultaneous biaxial stretching tenter, first stage stretching temperature 90 ° C, first stage stretching ratio (length / width) 3.5 / 3.5 times, Second stage stretching temperature 160 ° C, second stage stretching ratio (length / width) 1.8 times / 1.2 times, total stretching ratio (length / width) 6.3 times / 4.2 times, heat setting temperature 210 ° C, relaxation heat treatment I longitudinal relaxation rate The film was formed under the conditions of 2% relaxation heat treatment II longitudinal relaxation rate of 4%. The film temperature is heated to 89 ° C., and the film is simultaneously biaxially stretched at an area stretch ratio of 12.25 times (longitudinal magnification: 3.5 times, lateral magnification: 3.5 times). Subsequently, the film temperature was set to 160 ° C., and the film was stretched again at an area stretching ratio of 2.16 times (longitudinal magnification: 1.8 times, lateral magnification: 1.2 times), and heat-fixed at a heat-fixing temperature of 210 ° C. for 2 seconds. After the treatment, a relaxation heat treatment I of 2% in the longitudinal direction and the width direction is performed at the heat setting temperature, and then a relaxation heat treatment II of 4% in the longitudinal direction and 2% in the width direction is combined in two stages of 150 ° C and 100 ° C. And a biaxially stretched polyester film having a thickness of 5 μm was obtained. The composition, characteristics, etc. of this biaxially oriented polyester film were as shown in the table, and had excellent characteristics as a base film for magnetic recording media.

(Example 18)
A PEI / PPS blend chip was produced in the same manner as in Example 16 except that the contents of the resin constituting the film and the compatibilizer were changed to the conditions shown in the table. In the same manner as in Example 1, 50 parts by weight of PBT and 50 parts by weight of polyetherimide (PEI) “Ultem” manufactured by General Electric were dehumidified and dried at 150 ° C. for 5 hours, and then heated to 300 to 290 ° C. Was supplied to a vented twin-screw extruder equipped with a twin-screw three-stage screw and melt-extruded with a residence time of 3 minutes to obtain a PBT / PEI blend chip containing 50% by weight of PEI.
The obtained PEI / PPS blend chips were separately dried at 180 ° C. under reduced pressure of 1 mmHg for 3 hours, and PBT as polyester was separately dried at 160 ° C. under reduced pressure of 1 mmHg for 6 hours. After drying, 30 parts by weight of PEI / PPS blend chip and 70 parts by weight of PBT are put into the above twin screw kneader / extruder and melt-extruded at a residence time of 90 seconds, screw speed of 300 rpm and 280 ° C and discharged in a strand form. After cooling with water at a temperature of 25 ° C., cutting was performed immediately to prepare a PBT / PEI / PPS blend chip.

  The obtained PBT / PEI / PPS blend chip, PBT and PBT / PEI blend chip are dried in a vacuum dryer at 160 ° C for 5 hours to remove moisture sufficiently, and the weight fraction of each resin in the film is shown in the table. After mixing and mixing the polyester resin to a single screw extruder, melting it at 280 ° C, passing through a filter and gear pump, removing foreign matter and leveling the extrusion amount, The sheet was discharged in the form of a sheet on a cooling drum whose temperature was controlled to 20 ° C. At that time, a wire-like electrode having a diameter of 0.15 mm was applied electrostatically and adhered to the cooling drum to obtain an unstretched film. Next, the film temperature is raised with a heating roll before stretching in the longitudinal direction, and finally the film temperature is stretched 3.1 times in the longitudinal direction at 89 ° C., and then the preheating temperature is 80 ° C. with a tenter-type transverse stretching machine, The film was stretched 3.1 times in the width direction at a stretching temperature of 89 ° C and heat treated for 4 seconds at 210 ° C while relaxing 3% in the width direction in the tenter to obtain a biaxially oriented film with a film thickness of 12 µm. It was. The characteristics of the obtained biaxially oriented film are shown in the table. The biaxially oriented film obtained in this example was excellent in Young's modulus. It also showed excellent dielectric breakdown characteristics.

(Example 19)
A PEI / PPS blend chip was produced in the same manner as in Example 16 except that the contents of the resin constituting the film and the compatibilizer were changed to the conditions shown in the table. Further, 50 parts by weight of PPT dried at 120 ° C. for 5 hours under reduced pressure of 1 mmHg in the same manner as in Example 1 and 50 parts of polyetherimide (PEI) “Ultem” made by General Electric Co., Ltd. dehumidified and dried at 150 ° C. for 5 hours. PPT / containing 50% by weight of PEI by feeding to a bent type twin screw extruder equipped with a twin screw three stage type screw heated to 270 to 300 ° C. A PEI blend chip was obtained.
The obtained PEI / PPS blend chip was separately dried at 180 ° C. for 3 hours under 1 mmHg reduced pressure, and PPT as a polyester was separately dried at 120 ° C. for 6 hours under 1 mmHg reduced pressure. After drying, 30 parts by weight of PEI / PPS blend chip and 70 parts by weight of PPT are put into the above twin screw kneader / extruder and melt-extruded at a residence time of 90 seconds, screw speed of 300 revolutions / minute, 270 ° C and discharged in a strand form. After cooling with water at a temperature of 25 ° C., cutting was performed immediately to produce a PPT / PEI / PPS blend chip.

  The resulting PPT / PEI / PPS blend chip, PPT and PPT / PEI blend chip are dried in a vacuum dryer at 120 ° C for 7 hours to fully remove moisture, and the weight fraction of each resin in the film is shown in the table. After mixing and mixing the polyester resin to a single screw extruder, melting at 260 ° C, passing through a filter and gear pump, removing foreign matter and leveling the extrusion amount, The sheet was discharged in the form of a sheet on a cooling drum whose temperature was controlled to 20 ° C. At that time, a wire-like electrode having a diameter of 0.15 mm was applied electrostatically and adhered to the cooling drum to obtain an unstretched film. Next, the film temperature is raised with a heating roll before stretching in the longitudinal direction, and finally the film temperature is stretched 3.1 times in the longitudinal direction at 89 ° C., and then the preheating temperature is 80 ° C. with a tenter-type transverse stretching machine, The film was stretched 3.1 times in the width direction at a stretching temperature of 89 ° C and heat treated for 4 seconds at a temperature of 200 ° C while relaxing 3% in the width direction in the tenter to obtain a biaxially oriented film with a film thickness of 15 µm. It was. The characteristics of the obtained biaxially oriented film are shown in the table. The biaxially oriented film obtained in this example was excellent in Young's modulus. It also showed excellent dielectric breakdown characteristics.

(Examples 20 to 31)
The PPS-1 resin prepared in Reference Example 4 was dried at 180 ° C. under reduced pressure of 1 mmHg for 3 hours, and polyetherimide (“ULTEM 1010” manufactured by GE Plastics) (hereinafter referred to as PEI) was used as polyimide (b). They were dried separately at 120 ° C. for 3 hours under a reduced pressure of 1 mmHg. After mixing 50 parts by weight of the above PPS-1 resin and 50 parts by weight of PEI with 1.5 parts by weight of γ-isocyanatopropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., “KBE9007”) under dry air, kneading paddle Charged into a co-rotating twin-screw kneading and extruding machine (manufactured by Nippon Steel Works, screw diameter 30 mm, screw length / screw diameter = 45.5) with three vacuum kneading sections, residence time 90 seconds, screw rotation speed It was melt-extruded at 300 rpm at 330 ° C., discharged into a strand, cooled with water at a temperature of 25 ° C., and immediately cut to produce a blend chip. The obtained PPS / PEI (50/50 parts by weight) blended chip raw material with 0.3 parts by weight of water added per 100 parts by weight was charged into the above twin-screw kneading extruder, residence time 90 seconds, screw A PEI / PPS blend chip was produced by melt extrusion at 330 ° C., 330 ° C., and discharging into a strand, cooling with water at a temperature of 25 ° C., and immediately cutting.

  The obtained PEI / PPS blend chip and a PET resin (grade name: J055, intrinsic viscosity IV = 1.15 dL / g) manufactured by Mitsui Chemical Co., Ltd. were separately dried under reduced pressure of 1 mmHg at 180 ° C. for 3 hours. After drying, 30 parts by weight of PEI / PPS blend chip and 70 parts by weight of PET are put into the above-mentioned twin-screw kneader / extruder, melt residence time is 90 seconds, screw speed is 300 revolutions / minute, and it is melt extruded at 300 ° C and discharged into a strand. After cooling with water at a temperature of 25 ° C., it was immediately cut to prepare a PET / PEI / PPS blend chip.

  The obtained PET / PEI / PPS blend chip, the PET obtained in Reference Example 1 and the PET / PEI blend chip A prepared in Example 1 have the weight fraction of each resin in the film as shown in the table. Then, each chip was supplied to a full flight single screw extruder whose melting part was heated to 295 ° C.

  Next, the polymer melted by the extruder is filtered through a filter set at a temperature of 300 ° C., melt-extruded from a die of a T die set at a temperature of 300 ° C., and then adhered while applying an electrostatic charge to a cast drum having a surface temperature of 25 ° C. After cooling and solidification, an unstretched PET / PEI / PPS mixed film was produced.

  This unstretched PET / PEI / PPS film is stretched 3 times in the longitudinal direction of the film at a stretching temperature of 89 ° C. using a difference in the peripheral speed of the roll by using a longitudinal stretching machine composed of a plurality of heated roll groups. The film was stretched at a magnification of 4 times. Thereafter, both ends of the film were gripped with clips, led to a tenter, stretched 3.8 times in the width direction at a temperature of 89 ° C., and subsequently heat treated at a temperature of 210 ° C. for 3 seconds (in the width direction). 2% relaxation treatment), followed by further 2% relaxation treatment in the width direction at a temperature zone of 150 ° C., and then slowly cooled to room temperature to obtain a biaxially oriented film having a thickness of 25 μm. The characteristics of the obtained biaxially oriented film are shown in the table. The biaxially oriented films obtained in Examples 20 to 31 were each excellent in moisture and heat resistance. It also showed excellent dielectric breakdown characteristics.

Here, abbreviations in the table are shown below.
PET: Polyethylene terephthalate PEN: Polyethylene-2,6-naphthalate PPS: Polyphenylene sulfide PEI: Polyetherimide PBT: Polybutylene terephthalate PPT: Polypropylene terephthalate

  The biaxially oriented film of the present invention has excellent wet heat resistance and dielectric breakdown characteristics. The use of the biaxially oriented film of the present invention is not particularly limited, but for printing materials such as process / release materials, electrical insulating materials, solar cell materials, circuit board materials, capacitors, packaging, ink ribbons, It can be widely used for various industrial materials such as molding materials, and its industrial value is extremely high.

Claims (8)

Polyester (a), polyimide (b), polyarylene sulfide (c) and a film containing a compatibilizer (d),
The content of each of the polyester (a), polyimide (b), and polyarylene sulfide (c) in the film is (a) 50 to 98% by weight, (b) 1 to 30% by weight, (c) 0.1 to In the range of 30% by weight,
Polyimide (b) and polyarylene sulfide (c) each form a dispersed phase,
The average dispersion diameter of the polyimide (b) is 1 to 50 nm,
The average dispersion diameter of the polyarylene sulfide (c) is in the range of 50 to 500 nm,
A biaxially oriented film having an elongation half-life of 30 to 120 hours according to a heat and humidity test. The polyester (a) content in the film (a) is in the range of 50 to 90% by weight with respect to the sum of the polyester (a), polyimide (b), and polyarylene sulfide (c) in the film,
The content of polyarylene sulfide (c) is in the range of 1 to 30% by weight,
2. The biaxially oriented film according to claim 1, wherein the film has an elongation half-life of 60 hours or more and 120 hours or less by a heat and humidity resistance test. 3. The biaxially oriented film according to claim 1, wherein the weight ratio of the polyimide (b) and the polyarylene sulfide (c) contained in the film satisfies the following formula.
0.01 ≤ c / b ≤ 3.0 4. The biaxially oriented film according to claim 1, wherein a silicon atom (Si) is contained in the dispersed interface phase of the polyimide (b) or the polyarylene sulfide (c) in the film. The biaxially oriented film according to any one of claims 1 to 4, wherein the polyester (a) is polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate or a modified product thereof. 6. The biaxially oriented film according to any one of claims 1 to 5, wherein the polyimide (b) is a polyetherimide. The biaxially oriented film according to any one of claims 1 to 6, wherein the polyarylene sulfide (c) is polyphenylene sulfide. The biaxially oriented film according to any one of claims 1 to 7, which is used as a magnetic recording medium.