JP2011162771A - Biaxially oriented polyphenylene sulfide film and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biaxially oriented film that improves thermal dimensional stability and elongation at break and excels in processability while maintaining excellent properties of polyphenylene sulfide and that is suitably used for various films for industrial materials, such as ones for electrical insulation, solar cells, packaging, ink ribbons, circuit boards, and capacitors. <P>SOLUTION: The biaxially oriented polyphenylene sulfide film contains 0.1-8 wt.% of a polyester resin including an ethylene terephthalate unit as a main component, in a polyphenylene sulfide resin when the sum of the weight of the polyphenylene sulfide resin and the weight of the polyester resin is taken as 100 wt.%, and elongation at break in the longitudinal direction and the width direction of the film is 70% or more. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a biaxially oriented polyphenylene sulfide film.

  Polyphenylene sulfide (hereinafter sometimes abbreviated as PPS) having excellent heat resistance, hydrolysis resistance, barrier properties, chemical resistance, electrical insulation, etc. has properties suitable as engineering plastics. It is used for electrical / electronic parts, machine parts and automobile parts. However, PPS lacks toughness and is used in electrical insulation materials for water heater motors that require bending during processing, as well as electrical insulation materials for motors and drive motors for car air conditioners used in hybrid vehicles. It cannot be said that the elongation at break is sufficient, and it has been pointed out that there is a lack of toughness such as the occurrence of cracks during processing. Also, in applications that are used by bonding to different materials such as solar cell backsheets and circuit boards, improvement in dimensional stability is required, and improvements are required, but PPS films that still meet this requirement There was no.

  Moreover, since the crystal melting temperature of PPS is as high as 280 ° C., it is necessary to set the heating temperature at the time of melt extrusion to a high temperature of 320 ° C. or higher in order to give sufficient fluidity when forming a film, Since a large amount of energy is required, a film forming method with low energy consumption is required from an environmental point of view.

  Several attempts to improve the performance of PPS resin by mixing other resins are known.

  For example, Patent Document 1 proposes a PPS film in which polyethylene terephthalate (hereinafter abbreviated as PET) is blended with PPS and has improved thermal dimensional stability. However, since the PET content is large, the heating temperature during melt extrusion is high. For this reason, the thermal decomposition of PET was induced and its mechanical properties were not sufficient, and the dimensional stability was insufficient. Patent Document 2 discloses an example in which the toughness is improved by finely dispersing PET in PPS to form a two-phase continuous structure. However, this also had the same problem as the above example because of the high PET content.

Japanese Patent Laid-Open No. 7-88954 Japanese Patent Laid-Open No. 2004-231909

  An object of the present invention is to provide a biaxially oriented PPS film having improved thermal dimensional stability and elongation at break while maintaining excellent properties of PPS and improved workability. Another object is to provide a means for producing an environmentally friendly PPS film.

  In order to achieve the above object, the present invention has the following configuration. That is, the polyphenylene sulfide resin contains 0.1% by weight or more and 8% by weight or less of a polyester resin having an ethylene terephthalate unit as a main component when the sum of the weight of the polyphenylene sulfide resin and the weight of the polyester resin is 100% by weight; The main point is that the film is a biaxially oriented polyphenylene sulfide film having a breaking elongation of 70% or more in the longitudinal direction and the width direction of the film.

  According to the present invention, the thermal dimensional stability and elongation at break can be improved while maintaining the excellent characteristics of PPS, and the workability can be improved. Therefore, for electrical insulation, for solar cells, for packaging, and for ink ribbons Films for various industrial materials such as for automobiles, circuit boards and condensers. Specifically, electrical insulation materials for water heater motors, electrical insulation materials for motors and drive motors for car air conditioners used in hybrid vehicles, etc. It can be suitably used as a solar battery backsheet or a circuit board film used for bonding with a different material. Moreover, since the fluidity at the time of melt extrusion can be improved and the temperature at the time of melt extrusion can be set to 300 ° C. or less, it is environmentally friendly.

  Hereinafter, the biaxially oriented laminated film of the present invention will be described.

  The biaxially oriented PPS film of the present invention contains 0.1 wt% or more and 8 wt% or less of a polyester resin containing ethylene terephthalate units as a main component when the sum of the weight of the polyphenylene sulfide resin and the weight of the polyester resin is 100 wt%. Is.

  The inventors have discovered a very interesting fact while studying the melt flow properties of a mixture of a PPS resin and a polyester resin based on ethylene terephthalate units. That is, when the content of the polyester is gradually increased from 0% by weight, the melt viscosity shows a tendency to decrease. When the content exceeds 3%, the melt viscosity is reversed and when the content exceeds 10%, the original PPS is increased. This is a phenomenon in which the melt viscosity is lower than that of the original PPS but is almost fluid. That is, when the content exceeds 10%, heating at about 320 ° C. is necessary for stable film formation. A decrease in melt viscosity means that extrusion at a lower temperature is possible. Surprisingly, when the content of the polyester is in the range of 0.1 wt% to 8 wt% when the sum of the weight of the polyphenylene sulfide resin and the weight of the polyester resin is 100 wt%, the elongation at break It was also found that a film with improved thermal dimensional stability can be obtained and is suitable for molding.

  The reason for this is not clear, but it is assumed that a polyester mainly composed of ethylene terephthalate units enters between PPS molecules to plasticize and fluidize the resin composition. If the content of the polyester resin containing ethylene terephthalate units as the main component is less than 0.1% by weight, the fluidity is not good, and the contribution to the physical properties of the polyester resin is small, so that sufficient film physical properties can be obtained. I can't. In addition, when the amount is more than 8% by weight, the fluidity cannot be improved, and therefore, melt extrusion at a high temperature is unavoidable, and the thermal decomposition of the polyester proceeds, resulting in deterioration of mechanical properties and film formation. Since the polyester induces tearing and dilutes the PPS characteristics (chemical resistance, heat resistance, flame retardancy, etc.), sufficient film physical properties cannot be obtained. Polyester resin content with ethylene terephthalate unit as the main component suppresses cracking when processing electrical insulation materials for water heater motors, electrical insulation materials for car air conditioners and drive motors used in hybrid vehicles, etc. From the viewpoint of achieving the above, it is more preferably 0.1% by weight or more and less than 5% by weight, and further preferably 0.5% by weight or more and less than 5% by weight.

In the present invention, the melt viscosity of the mixture of the PPS resin and the polyester resin containing ethylene terephthalate units as a main component is preferably in the range of 100 to 700 Pa · s at a temperature of 290 ° C. and a shear rate of 100 sec ^−1. More preferably, it is in the range of 200 to 500 Pa · s.

  In the present invention, the time when the polyphenylene sulfide resin contains the polyester resin containing ethylene terephthalate units as the main component is not particularly limited. Then, there are a method of forming a master chip, a method of mixing and melt-kneading at the time of melt extrusion. Since high dispersibility can be realized by performing pre-melt kneading, a method of pre-kneading into a master chip using a high-shear mixer with high shear stress such as a twin screw extruder is preferably exemplified. In particular, a method of pre-melt kneading (pelletizing) a mixture of polyphenylene sulfide and a polyester mainly composed of ethylene terephthalate units before melt extrusion to form a master chip is preferable.

  The PPS used in the biaxially oriented polyphenylene sulfide film of the present invention is preferably a p-phenylene sulfide unit represented by the following structural formula as a main structural unit of the polymer, preferably 80 mol% or more, more preferably 90 mol% or more, still more preferably Is a polymer containing 95 mol% or more. If 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. Examples of such units include trifunctional units, ether units, sulfone units, ketone units, meta bond units, aryl units having functional groups such as alkyl groups, biphenyl units, terphenylene units, Examples include vinylene units and carbonate units, and specific examples include the following structural units. One or more of these can coexist. In this case, the structural unit may be included in either a random type or a block type.

  Use of PPS consisting essentially of p-phenylene sulfide, or PPS containing 1 mol% or less of trifunctional components and 99 mol% or more of p-phenylene sulfide is used. It is preferable from the viewpoint of performance. In this case, the PPS resin has a melting point of 280 to 290 ° C. and a glass transition temperature of 90 to 95 ° C.

  In the present invention, from the viewpoint of improving the resin fluidity at the time of melt extrusion of PPS and improving the film processability, when the sum of the weight of the polyphenylene sulfide resin and the weight of the polyester resin is 100% by weight, the polyphenylene sulfide resin contains The copolymerized polyphenylene sulfide resin is preferably contained in an amount of 30% by weight or more. More preferably, it is contained in an amount of 50% by weight or more, more preferably 70% by weight or more. The upper limit of the content of the copolymerized polyphenylene sulfide resin is 99.9% by weight. The copolymerized polyphenylene sulfide resin referred to in the present invention is obtained by copolymerizing a p-phenylene sulfide unit and a phenylene sulfide unit other than p-phenylene sulfide, that is, an m-phenylene sulfide unit or an o-phenylene sulfide unit. This copolymerized polyphenylene sulfide resin has a lower melting point than PPS consisting essentially only of p-phenylene sulfide, so that copolymerization is achieved when the sum of the weight of the polyphenylene sulfide resin and the weight of the polyester resin is 100% by weight. By mixing polyphenylene sulfide within the preferable range of the present invention, the melting point of the polyphenylene sulfide resin matrix itself can be effectively lowered, and as a result, the melt extrusion temperature can be lowered. Moreover, it becomes easy to improve breaking elongation by containing copolymerization polyphenylene sulfide resin. The reason for this is not clear, but because the skeleton of the copolymerized phenylene sulfide is bent as compared with the p-phenylene sulfide skeleton, the molecular chain entanglement increases, and the molecular chain slippage during the tensile test is substantially reduced. It is presumed that the elongation is improved by an effect that is suppressed compared to PPS consisting of only PPS.

  On the other hand, if the copolymerized polyphenylene sulfide is less than 30% by weight, the effect of lowering the melting point of the polyphenylene sulfide resin matrix itself is small, and it may be difficult to improve the elongation at break. The copolymer unit is preferably an m-phenylene sulfide unit, and the copolymerization amount of the unit is preferably 3 mol% or more and 50 mol% or less, more preferably 5 mol% or more and 30 mol% or less, and still more preferably. Is 8 mol% or more and 15 mol% or less. When the copolymerization component is less than 3 mol%, the melting point is high, and when it exceeds 50 mol%, the heat resistance, which is a characteristic of the polyphenylene sulfide resin, may be significantly reduced.

  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. It can be produced by a method for obtaining a polymer having a relatively large molecular weight as described in Japanese Patent No. 7332.

  In the present invention, the PPS resin is subjected to crosslinking / high molecular weight heating by heating in air, heat treatment under an inert gas atmosphere such as nitrogen or reduced pressure, washing with an organic solvent, hot water and an aqueous acid solution, an acid anhydride, It can also be used after various treatments such as activation with functional group-containing compounds such as amines, isocyanates and functional 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 acetic acid or acetate at 30 to 100 ° C. for 10 to 60 minutes, washed with ion exchange water several times at 30 to 80 ° C. and dried to obtain a PPS powder. This 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-exchanged water at 30 to 80 ° C., and under reduced pressure of 5 torr or less. dry. Since the polymer thus obtained is a substantially linear PPS polymer, 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.

  Next, the polyester mainly composed of ethylene terephthalate units used in the present invention is a polyester containing at least 70 mol% or more of ethylene terephthalate units. Desirably, the polyester contains 80 mol% or more of ethylene terephthalate units. Less than 30 mol% generally contains units formed from other acid components or other glycol components, but p-hydroxybenzoic acid, m-hydroxybenzoic acid, 2,6-hydroxynaphthoic acid, etc. The aromatic hydroxycarboxylic acid and p-aminophenol, p-aminobenzoic acid, and the like can be included as long as the effects of the present invention are not impaired.

  The intrinsic viscosity (IV) of the polyester mainly composed of an ethylene terephthalate unit used in the present invention is preferably 0.55 to 2.0 dl / from the viewpoint of film formation stability and ease of kneading with PPS. g, more preferably 0.6 to 1.4 dl / g.

  Although the specific example which obtains the polyester resin used for this invention below is shown, this invention is limited to these description and is not interpreted.

  A dicarboxylic acid or an ester derivative thereof and a glycol component such as ethylene glycol are heated and dissolved in the presence of an esterification or transesterification catalyst such as magnesium acetate and subjected to esterification or transesterification by a conventional method. In order to make the amount of ethylene phthalate units within a desired range, it is easy to adjust the composition of the raw materials. After completion of the esterification or transesterification reaction, a metal compound catalyst such as germanium dioxide and / or a phosphorus compound such as trimethyl phosphate is added, and then the reaction system is gradually depressurized while heating up to reduce the pressure to 1 mmHg or less. Below, the polymerization reaction is advanced at 290 ° C. by a conventional method to obtain a polyester mainly composed of ethylene terephthalate having an intrinsic viscosity of about 0.5 dl / g. In the present invention, from the viewpoint of stabilizing the film forming property by setting the intrinsic viscosity of the film to 0.6 dl / g or more, the obtained polyester resin having an intrinsic viscosity of about 0.5 is in a chip shape and is 180 ° C. or less in advance. After precrystallization at a temperature of 190 ° C. to 250 ° C. under a reduced pressure of about 1 torr for 10 to 40 hours to obtain a polyester chip having an intrinsic viscosity of 0.6 dl / g to 2.0 dl / g. It is preferable. The conditions of the solid phase polymerization temperature and the solid phase polymerization time can be appropriately changed depending on the type and amount of the metal compound added to the polyester, the type and amount of the phosphorus compound, the intrinsic viscosity, and the like. In the present invention, after preliminarily crystallizing at a temperature of 180 ° C. or lower in advance, it is preferable to carry out solid phase polymerization at 190 to 250 ° C. under reduced pressure of about 1 torr for 10 to 35 hours. In addition, as a polymerization catalyst in the polycondensation reaction, a normal polyester polymerization catalyst can be appropriately used. For example, antimony type such as antimony trioxide, manganese type such as manganese oxide, germanium type such as germanium oxide, various titanium types, and aluminum type compounds may be mentioned.

  When the particles are added, for example, if the water sol or alcohol sol obtained at the time of synthesis is added without drying, the dispersibility of the particles is good. It is also effective to add a water slurry of particles to the polyester and knead it into the polyester using a vented twin-screw kneading extruder. As a method of adjusting the content and number of particles, a master of high-concentration particles is prepared by the above method, and it is diluted with polyester that does not substantially contain particles at the time of film formation to adjust the content of particles. The method to do is effective.

  The breaking elongation in the longitudinal direction and the width direction of the biaxially oriented polyphenylene sulfide film of the present invention is 70% or more. By using such a film, it is possible to suppress cracking during processing of an electrical insulation material for a water heater motor, an electrical insulation material for a car air conditioner motor and a drive motor used in a hybrid vehicle, and the like. The breaking elongation in the longitudinal direction and the width direction is preferably 80% or more, more preferably 100% or more. When the elongation at break in the longitudinal direction and the width direction of the film is less than 70%, for example, when used for motor insulation, the toughness is insufficient in the slot liner or wedge insertion process that requires flexibility, Problems such as cracks are likely to occur. The upper limit of the elongation at break is not particularly limited, but is 200%. When the elongation at break is 200% or more, it may be necessary to make the draw ratio at the time of film formation extremely low, and the orientation of the molecular chain becomes weak, so that the flatness of the film deteriorates in the drawing process. Because there is a fear. In order to make the elongation at break 70% or more, as will be described later, for example, the maximum temperature during melt extrusion during film formation is 300 ° C. or less, and the heat setting after biaxial stretching is 240 ° C. This can be achieved by a method of applying at a temperature of 280 ° C. or lower.

  The biaxially oriented polyphenylene sulfide film of the present invention preferably has a sum of the heat shrinkage in the longitudinal direction and the width direction of 2.5% or less when heated at 150 ° C. for 30 minutes. More preferably, it is 2.0% or less, More preferably, it is 1.5% or less. When the sum of the heat shrinkage ratios in the longitudinal direction and the width direction exceeds 2.5%, for example, for solar cell backsheets and circuit boards used for bonding with different materials, the manufacturing process and high temperature environment during use In applications exposed to the above, warping (curling) may occur, and dimensional stability may be inappropriate. In order to achieve such a range of heat shrinkage rate, it can be achieved by appropriately adjusting the stretching ratio, stretching temperature, and heat treatment conditions after stretching, and as will be described later, the heat after biaxial stretching is achieved. Fixing is preferably performed at a temperature of 240 ° C. or higher and 280 ° C. or lower.

  The biaxially oriented polyphenylene sulfide film of the present invention can contain organic or inorganic particles for imparting slipperiness, abrasion resistance, scratch resistance to the film, and improving processability. Examples of the particles include inorganic particles such as titanium oxide, calcium carbonate, silica, alumina and zirconia, and inert particles such as silicone particles, organic particles such as crosslinked acrylic particles and crosslinked polystyrene particles, and calcium acetate during polymerization of the polymer. It is also possible to deposit particles in the course of polymer polymerization using lithium or lithium acetate.

  Although the thickness of the biaxially oriented laminated film of the present invention can be appropriately determined according to the purpose, it is 10 μm or more and 500 μm or less, preferably 25 μm or more and 350 μm or less. If the thickness of the film is less than 10 μm, the strength of the whole film will be insufficient and the handling properties will deteriorate. For example, if it is used for motor insulation, the electrical insulation will be insufficient, while if it exceeds 500 μm, the film will become stiff. It should be noted that processing becomes difficult.

  Further, organic lubricants such as heat stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, flame retardants, pigments, dyes, fatty acid esters and waxes may be added within the range not impairing the object of the present invention. Good.

  Furthermore, the biaxially oriented polyphenylene sulfide film of the present invention may be subjected to processing such as heat treatment, molding, surface treatment, laminating, coating, printing, embossing and etching, as long as the object of the present invention is not impaired.

  Next, the method for producing the biaxially oriented film of the present invention will be described with specific examples, but it is needless to say that the present invention is not construed as being limited by this description.

  The example of the method of obtaining the polyester resin which has ethylene terephthalate as a main component is as having demonstrated previously.

  The PPS resin can be obtained, for example, by reacting sodium sulfide and p-dichlorobenzene 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 can be added as a polymerization degree adjusting agent, and the 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. Since the polymer thus obtained is a substantially linear PPS polymer, stable film formation and stretching are possible. 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 Further, a heat stabilizer and an antioxidant may be added.

Subsequently, the manufacturing method of the master pellet of the polyester resin which has PPS resin and ethylene terephthalate as a main component is described below. First, a polyester resin containing ethylene terephthalate as a main component is dried under reduced pressure at a crystallization temperature or higher and a melting point or lower, preferably 140 to 200 ° C. for 2 to 5 hours. PPS does not need to be dried, but may be dried under the same conditions as polyester having ethylene terephthalate as a main component for the purpose of removing adsorbed water on the surface. A polyester resin mainly containing dried ethylene terephthalate and a PPS resin are blended and supplied to a vent type twin screw extruder heated to 270 ° C to 320 ° C. The screw configuration of the twin screw extruder is preferably provided with a kneading zone made of paddles, dull mages or the like. Shear rate is preferably 50~400sec ^-1, more preferably 100~300sec ^-1. When the shear rate is 50 sec ^-1 or less can not be obtained sufficiently dispersed state, when the shear rate exceeds 300 sec ^-1, not only the temperature control becomes difficult due to generation of heat-generating, cause degradation of the polymer there is a possibility. The residence time of the kneaded polymer is preferably 0.5 to 10 minutes, more preferably 1 to 5 minutes. If the residence time is less than 0.5 minutes, a sufficient dispersion state cannot be obtained, and if it exceeds 10 minutes, the polymer may be decomposed. Moreover, you may mix | blend and disperse | distribute a dispersing agent in order to improve a dispersibility in this kneading | mixing process.

  The polyester master chip containing PPS / ethylene terephthalate as a main component thus obtained is vacuum-dried at 180 ° C. for 3 hours or more and put into an extruder heated to a temperature of 270 to 300 ° C. In the present invention, it is important that the heating temperature at the time of melt extrusion of the extruder is 300 ° C. or less. When the heating temperature exceeds 300 ° C., the polyester resin containing ethylene terephthalate as a main component will be deteriorated and the elongation at break will be lowered. It becomes easy to cause tearing during filming.

  The molten polymer that has passed through the extruder is passed through a filter and discharged into a sheet using a die of a T die. This sheet-like material is brought into close contact with a cooling drum having a surface temperature of 20 to 60 ° C. to be cooled and solidified to obtain a substantially non-oriented unstretched film.

  Next, this unstretched film is biaxially stretched. Stretching methods include sequential biaxial stretching methods (stretching methods that combine stretching in each direction, such as a method of stretching in the width direction after stretching in the longitudinal direction), and simultaneous biaxial stretching methods (in the longitudinal direction and the width direction). The method of extending | stretching simultaneously), or the method which combined them can be used.

  A sequential biaxial stretching method will be described as a specific example. In sequential biaxial stretching, an unstretched film is heated with a heating roll group, and the stretching ratio is 3.0 to 4.5 times in the longitudinal direction (MD direction). Preferably, the film is stretched in a multistage of 3.1 to 4.0 times, more preferably 3.2 to 3.8 times in one or more stages (MD stretching). The stretching temperature ranges from Tg (glass transition temperature of a PPS resin containing a polyester resin containing ethylene terephthalate units as a main component) to (Tg + 50) ° C., preferably (Tg + 2) to (Tg + 40) ° C. In the case of the film of this invention, extending | stretching temperature is 90 to 135 degreeC, More preferably, it is 92 to 125 degreeC. Thereafter, it is cooled by a cooling roll group of 20 to 50 ° C.

  For stretching in the width direction (TD direction) following stretching in the MD direction, for example, a method using a tenter is generally used. The both ends of this film are gripped with clips, guided to a tenter, and stretched in the width direction (TD stretching). The stretching temperature is preferably Tg (glass transition temperature of a PPS resin containing a polyester resin containing ethylene terephthalate units as a main component) to (Tg + 50) ° C., more preferably (Tg + 2) to (Tg + 40) ° C. In the case of the film of the present invention, the stretching temperature is 90 ° C to 135 ° C, more preferably 92 ° C to 125 ° C. The draw ratio is in the range of 3.0 to 4.5 times, preferably 3.1 to 4.0 times, and more preferably 3.2 to 3.8 times. From the viewpoint of improving the flatness and workability after stretching and the thermal dimensional stability, the area ratio (the product of the MD direction stretching ratio and the TD direction stretching ratio) is preferably 8 times or more and 15 times or less, preferably 9 times or more, 14 A ratio of 2 times or less is more preferable. When the area stretch ratio is less than 8 times, the orientation of the molecular chain during stretching is weak, and a film with poor planarity may be obtained after heat treatment. On the other hand, if the area stretch ratio exceeds 16 times, it may be necessary to make the stretch ratio during film formation extremely high, and the film break elongation decreases, so the effect of improving workability and thermal dimensional stability. It is difficult to obtain the effect of property, and the film may be broken in the stretching process.

  Next, this stretched film is heat-set under tension. In the biaxially oriented film of the present invention, it is important to carry out the heat setting temperature after stretching from a temperature in the vicinity of the melting point of PET, which cannot normally be taken by PET film formation, in a region beyond that, that is, below the melting point of PPS. The heat setting temperature is in the range of 240-280 ° C. The heat setting temperature is preferably 245 ° C to 275 ° C, more preferably 250 ° C to 270 ° C. When the heat setting temperature after stretching is less than 240 ° C., the melting of the strained amorphous chain and crystal structure of PET having a melting point near 250 ° C. is insufficient, and it is difficult to improve the elongation at break. In addition, since the crystal structure of PPS having a high melting point of 285 ° C. is insufficient, it may be difficult to obtain an improvement in thermal dimensional stability and the film may have insufficient dimensional stability.

  Following heat setting, the film is further subjected to a relaxation treatment in the width direction in a temperature zone of 40 to 230 ° C., more preferably a temperature zone not lower than the stretching temperature and not higher than the heat fixing temperature. The relaxation rate is preferably 1 to 10%, more preferably 2 to 9%, and further preferably 4 to 8%.

  Further, the film is cooled and rolled up to room temperature, if necessary, in the longitudinal and width directions, if necessary, to obtain the desired biaxially oriented polyphenylene sulfide film.

  The characteristic value measurement method and effect evaluation method of the present invention are as follows.

(1) Melt viscosity Using a flow tester CFT-500 (manufactured by Shimadzu Corporation), the base length is 10 mm, the base diameter is 1.0 mm, the preheating time is set to 5 minutes, the temperature is 290 ° C., and the shear rate is 100 sec. ^-1 was measured.

(2) Film thickness Using an electronic micrometer (K-312A type) manufactured by Anritsu Corporation, the film thickness was measured at a needle pressure of 30 g.

(3) Glass transition temperature (Tg) and melting temperature (Tm) of the film
The measurement was performed according to JIS K7121-1987. Using a differential scanning calorimeter DSC (RDC220) manufactured by Seiko Instruments Inc. and a disk station (SSC / 5200) manufactured by Seiko Instruments Inc. as a data analysis device, 5 mg of the sample was melted and held at 350 ° C. for 5 minutes on an aluminum tray, and rapidly cooled and solidified. The temperature was raised from room temperature at a heating rate of 20 ° C./min. At that time, the peak temperature of the endothermic peak of melting observed was defined as the melting temperature (Tm). 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.

(4) Breaking elongation In the longitudinal direction and the width direction of the film, strip-shaped samples having a length of 200 mm and a width of 10 mm were cut out and used for measurement. The elongation at break was measured at 25 ° C. and 65% RH using a tensile tester according to the method defined in ASTM-D882-97. 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.

(5) Thermal shrinkage at 150 ° C. According to JIS C2318 (1997), two lines are drawn on the film surface so that the width is 10 mm and the measurement length is about 200 mm, and the distance between the two lines is measured accurately. This is L0. This film sample is left in an oven at 100 ° C. or 150 ° C. for 30 minutes under no load, and then the distance between the two lines is measured again, this is taken as L1, and the thermal shrinkage rate is determined by the following equation.
Thermal contraction rate (%) = {(L0−L1) / L0} × 100.

(6) Flame retardance A horizontal marker line is placed at a position 125 mm from the lower end in the vertical direction of a 200 mm long × 50 mm wide film, and is wound around a 12.7 mmφ mandrel to form a cylindrical shape having a length of 200 mm. After the overlapping end of the cylindrical film mark line (positioned 125 mm from the lower end of the cylinder) and the upper end of the cylinder (75 mm in length) is fixed with cello tape (registered trademark), the mandrel is removed and the cylindrical film Make a film sample.
The upper opening of the cylindrical sample is sealed with a clip, the vertical axis is vertical, and the cylindrical sample is fixed at a position where the lower end of the cylindrical sample is 9.5 mm above the burner. Adjust the burner to make a 19 mm long blue flame, which is in contact with the lower end of the sample for 3 seconds and ignited and burned 20. Immediately after the fire is extinguished, the flame is contacted again in the same manner and the second combustion is performed. The burning time when burning by two flame contact was measured and judged according to the following criteria. In addition, the combustion test performed about 5 samples that the combustion time by a 2 times flame contact was measured for each flame for each sample. Judgment was made according to the following criteria by a total of 10 flame contact combustion times. Of the five tests, the flame retardancy when even one of the tests burned to a 125 mm marker line was x. ◎ and ○ are acceptable and × is unacceptable.
(Flame retardancy criteria)
(Double-circle): The combustion time after applying a flame every time is less than 10 seconds, and the sum total of the time to burn by 10 flame contact is 50 seconds or less.

    ◯: The above criteria cannot be satisfied, the combustion time after applying the flame every time is less than 30 seconds, and the total time for burning with 10 flame contacts is less than 200 seconds.

    ×: When even one line burns to the marking line. Or, the combustion time after applying the flame every time is 30 seconds or more, or the total time for burning with 10 flame contact is 200 seconds or more.

(7) Molding processability Using a motor processing machine (Odawara Engineering Co., Ltd.), the film is punched into a size of 12 × 80 mm (the longitudinal direction of the film is set to 80 mm), and further creased is processed at a total processing speed of 2 1,000 samples were produced at a rate of pcs / second, and the number of cracks or cracks was counted and judged as follows. ◎◎, ◎, ○ are acceptable and × are unacceptable.
◎: Less than 25 samples with cracks and cracks ◎: 25 to less than 50 samples with cracks and cracks O: 50 to less than 200 samples with cracks and cracks × : The number of samples in which cracks or cracks occurred was 200 or more.

(8) Defect foreign matter on the film surface Aluminum vapor deposition was performed on the film surface, observed with a phase contrast microscope at 250 times, and the number of coarse protrusions of 2 μm or more seen there was regarded as a defective foreign matter. Judged. (Double-circle) and (circle) pass and x do not pass.
：: Coarse protrusions less than 2/10 cm ² ○: Coarse protrusions of 2 or more and less than 7/10 cm ² ×: Coarse protrusions of 7/10 cm ² or more

(8) Film formation stability When the polyphenylene sulfide film was produced, the time during which the film could be formed without causing breakage of the film was determined according to the following criteria.
◎: No break after 2 hours ○: Break occurs 2 times or less in 2 hours ×: Break occurs 3 times or more in 2 hours

(9) Dimensional stability A. Production of copper foil-laminated laminate The surface of the sample film was subjected to surface activation treatment of corona discharge treatment, the film sample was cut into a size of 20 cm wide and 30 cm long, and a rolled copper foil having a thickness of 12 μm was laminated. After carrying out a heat press cure for 20 minutes under a condition of 270 ° C. and 5 MPa in a nitrogen atmosphere, a copper foil was etched to form an electric circuit having a model pattern. The following evaluation was performed after cooling to room temperature.

B. Dimensional stability of circuit board samples (evaluation of curl resistance)
A circuit board sample was placed on a flat table, and the lift (curl) of the sample end face was measured and evaluated according to the following criteria. The more samples with less lift, the better the dimensional stability as a circuit board, and ◎ and ○ are acceptable and × is unacceptable.

  A: Among the four corners of each sample, 90 or more out of 100 samples have a lifting height of 10 mm or less at the portion with the largest lifting.

  A: Among the four corners of each sample, 70 to 89 of 100 samples have a lift height of 10 mm or less at a portion where the lift is the largest.

X: Of the four corners of each sample, the number of samples with the largest lifting height of 10 mm or less is less than 70 out of 100 samples.

Specific examples of the present invention will be described below in comparison with comparative examples.

(Reference Example 1) Production of poly-p-phenylene sulfide (PPS) In a 70 liter autoclave equipped with a stirrer, 8267.37 g (70.00 mol) of 47.5% sodium hydrosulfide and 2957.21 g of 96% sodium hydroxide (70.97 mol), N-methyl-2-pyrrolidone (NMP) 11434.50 g (115.50 mol), sodium acetate 2583.00 g (31.50 mol), and ion-exchanged water 10500 g were charged at normal pressure. The mixture was gradually heated to 245 ° C. over about 3 hours while introducing nitrogen, and after distilling 14780.1 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, 10235.46 g (69.63 mol) of p-dichlorobenzene and 900.00 g (91.00 mol) of NMP were added, the reaction vessel was sealed under nitrogen gas, and stirred at 240 rpm while stirring at 0.6 ° C. / The temperature was raised to 238 ° C. at a rate of minutes. 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 26300 g of NMP, the solvent and solid matter were filtered off with a sieve (80 mesh), and the resulting particles were washed with 31900 g of NMP and filtered off. This was washed several times with 56000 g of ion-exchanged water and filtered, then washed with 70000 g of 0.05 wt% aqueous calcium acetate and filtered. After washing with 70000 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 resin had a melt viscosity of 2000 poise (310 ° C., shear rate of 1000 sec ⁻¹ ), a glass transition temperature of 90 ° C., and a melting point of 285 ° C.

(Reference Example 2) Production of polyethylene terephthalate (PET) 0.09% by weight of calcium acetate and 0.03% by weight of antimony trioxide with respect to dimethyl terephthalate were added to a mixture of dimethyl terephthalate and ethylene glycol. The ester exchange reaction was carried out by heating with the method. Next, after adding 0.15% by weight of lithium acetate and 0.21% by weight of trimethyl phosphate to the raw material dimethyl terephthalate, the resulting transesterification product was transferred to a polymerization reaction tank, 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 by a conventional method to obtain polyethylene terephthalate (PET) having an intrinsic viscosity of 0.54 dl / g. The obtained PET polymer was heat-treated at a temperature of 225 ° C. for 20 hours under a reduced pressure of 1 mmHg or less using a rotary vacuum solid phase polymerization apparatus to obtain a PET polymer having an intrinsic viscosity of 0.70 dl / g.

Reference Example 3 Production of Copolymerized Polyphenylene Sulfide (m-PPS) 100 moles of sodium sulfide nonahydrate, 45 moles of sodium hydroxide and 25 liters of N-methyl-2-pyrrolidone (hereinafter referred to as NMP) in an autoclave Was gradually heated to 220 ° C. while stirring, and the contained water was removed by distillation. Into the system after dehydration, 86 mol% of p-dichlorobenzene as a main component monomer, 15 mol% of m-dichlorobenzene as a secondary component monomer, and 0.2 mol% of 1,2,4-trichlorobenzene were added. It was added together with 1 liter of NMP, and after 3 kg / cm ^{2 of} pressurized nitrogen was sealed at 170 ° C., the temperature was raised and polymerization was carried out at 260 ° C. for 4 hours. After completion of the polymerization, the mixture was cooled, the polymer was precipitated in distilled water, and a small polymer was collected with a wire mesh having a 150 mesh opening. This polymer was washed on the 5th floor with distilled water at 90 ° C. and then dried at 120 ° C. under reduced pressure to obtain a copolymerized polyphenylene sulfide (m-PPS) polymer in the form of white particles. The obtained m-PPS resin had a melt viscosity of 2000 poise (310 ° C., shear rate 1000 / s), a glass transition temperature of 86 ° C., and a melting point of 260 ° C.

Example 1
97% by weight of the PPS resin obtained in Reference Example 1 and 3% by weight of the PET resin obtained in Reference Example 2 were dried at 150 ° C. and a reduced pressure of 133 Pa or less for 4 hours, respectively, and then heated to 280 to 320 ° C. Vent type twin screw extruder (L / D = 40, vent vacuum) equipped with a three-shaft type screw (PET and PPS kneading plasticization zone / Dalmage kneading zone / Fine dispersion compatibilizing zone by reverse screw dull mage) And PPS / PET master pellets containing 3% by weight of PET were obtained.

Next, the obtained PPS / PET master pellets were dried under reduced pressure at 180 ° C. for 3 hours, and then supplied to a full flight single-screw extruder in which the extruder melting section was heated to 300 ° C. The molten polymer was passed through a fiber sintered stainless steel metal filter (14 μm cut), melted and extruded from a die of a T die set at a temperature of 295 ° C., and an electrostatic charge was applied to a cast drum having a surface temperature of 25 ° C. The film was tightly cooled and solidified to produce an unstretched film.
This unstretched film was stretched at a magnification of 3.4 times in the longitudinal direction of the film at a temperature of 98 ° C. using a difference in peripheral speed of the roll using a longitudinal stretching machine composed of a plurality of heated roll groups. . Thereafter, both ends of the film are gripped with clips and guided to a tenter, stretched in the width direction of the film at a stretching temperature of 100 ° C. and a stretching ratio of 3.5 times, and subsequently subjected to heat treatment at a temperature of 260 ° C. for 8 seconds. Thereafter, the film was subjected to a 5% relaxation treatment in the transverse direction in a cooling zone controlled at 160 ° C. and cooled to room temperature, and then the film edge was removed to obtain a biaxially oriented film having a thickness of 125 μm. The composition and characteristics of the biaxially oriented film obtained in this example are as shown in Table 1, and the flowability is improved from the value of the melt viscosity, and the melt extrusion stable at the melt extrusion temperature of 300 ° C. Film formation was possible, and the film characteristics were also flame retardant, and the thermal dimensional stability and moldability were extremely excellent.

(Comparative Example 1)
After 100% by weight of the PPS resin obtained in Reference Example 1 was dried under reduced pressure at 180 ° C. for 3 hours, it was supplied to a full-flight single screw extruder in which the extruder melting section was heated to 320 ° C. The molten polymer is passed through a fiber sintered stainless metal filter (14 μm cut), then melt extruded from a die of a T die set at a temperature of 310 ° C., and an electrostatic charge is applied to a cast drum having a surface temperature of 25 ° C. A biaxially oriented film was obtained in the same manner as in Example 1 except that it was solidified by cooling and solidified to produce an unstretched film. The configuration and characteristics of the biaxially oriented film obtained in this Comparative Example are as shown in Table 2. Since the melt viscosity was high, it was necessary to melt and extrude at 320 ° C. In the film characteristics, the flame retardancy was excellent, but the elongation at break was low, so that the moldability was insufficient, the film had a large thermal shrinkage rate and insufficient thermal dimensional stability.

(Examples 2 to 5)
A biaxially oriented film was obtained in the same manner as in Example 1 except that the mixing ratio of the PPS resin and the PET resin was changed to the conditions shown in Table 1. The constitution and characteristics of the biaxially oriented film obtained in this example are as shown in Table 1. In each example, stable melt extrusion and film formation were possible at a melt extrusion temperature of 300 ° C. Regarding the film properties, the biaxially oriented film obtained in Example 2 has flame retardancy and was extremely excellent in thermal dimensional stability and molding processability. The biaxially oriented film obtained in Example 3 had flame retardancy, extremely excellent moldability, and had thermal dimensional stability. Although the biaxially oriented film obtained in Example 4 was slightly inferior in flame retardancy and molding processability, it was extremely excellent in thermal dimensional stability. The biaxially oriented film obtained in Example 5 was extremely incombustible, while its thermal dimensional stability and molding processability were slightly inferior, but at a level with no problem.

(Comparative Example 2, Comparative Example 3)
The mixing ratio of the PPS resin and the PET resin was changed to the conditions shown in Table 2, and the melt extrusion conditions were supplied to a full flight single screw extruder heated to 310 ° C and set to a temperature of 300 ° C. A biaxially oriented film was obtained in the same manner as in Example 1 except that it was melt-extruded from the die of the T die. The composition and characteristics of the biaxially oriented film of this comparative example are as shown in Table 2. Since the melt viscosity is high, it is necessary to carry out melt extrusion at 310 ° C. or higher, and the film is formed for 2 hours. Two tears occurred. Since the extrusion temperature was 310 ° C., foreign matter estimated to be a PET degradation product could be confirmed on the film surface. The biaxially oriented film obtained in Comparative Example 2 is excellent in flame retardancy, but has a foreign matter, so that the elongation at break is low, the moldability is insufficient, the heat shrinkage rate is large, and the dimensional stability is insufficient. Met. In addition, the biaxially oriented film obtained in Comparative Example 3 has excellent dimensional stability, but lacks flame retardancy, and because of foreign matter, it is a film having low elongation at break and insufficient moldability. It was.

(Example 6)
The extruder melt section was fed to a full flight single screw extruder heated to 290 ° C. The molten polymer is passed through a fiber sintered stainless metal filter (14 μm cut), melt-extruded from a die of a T die set at a temperature of 290 ° C., and an electrostatic charge is applied to a cast drum having a surface temperature of 25 ° C. A biaxially oriented film was obtained in the same manner as in Example 1 except that the film was solidified by cooling and solidified to produce an unstretched film. The composition and characteristics of the biaxially oriented film obtained in this example are as shown in Table 1. Stable melt extrusion and film formation at a melt extrusion temperature of 290 ° C. are possible, and the film characteristics are also flame retardant. It had excellent thermal dimensional stability and molding processability.

(Example 7, Example 8)
A biaxially oriented film was obtained in the same manner as in Example 1 except that the heat setting temperature condition after biaxial stretching was changed to the conditions shown in Table 1. The configuration and characteristics of the biaxially oriented film obtained in this example are as shown in Table 1. All of them were capable of stable melt extrusion and film formation at a melt extrusion temperature of 300 ° C. Although the film of Example 7 had flame retardancy in terms of film characteristics, since the heat setting temperature was as low as 240 ° C., both the thermal dimensional stability and molding processability were slightly inferior, but at a level with no problem. On the other hand, although the film of Example 8 had flame retardancy, the heat setting temperature was as high as 280 ° C. and excellent in thermal dimensional stability, but the elongation at break was insufficient and the molding processability was slightly inferior, There was no level.

(Comparative Example 4)
A biaxially oriented film was obtained in the same manner as in Example 1 except that the heat setting temperature condition after biaxial stretching was changed to the conditions shown in Table 2. The composition and characteristics of the biaxially oriented film obtained in this comparative example are as shown in Table 2. Since the biaxially oriented film obtained in this comparative example has a low heat setting temperature of 230 ° C., the elongation at break is low. The film had low moldability and insufficient heat shrinkage rate, and insufficient heat dimensional stability improvement effect.

Example 9
67% by weight of the PPS resin obtained in Reference Example 1, 3% by weight of the PET resin obtained in Reference Example 2, and 30% by weight of the m-PPS resin obtained in Reference Example 3 were each obtained under reduced pressure of 150 ° C. and 133 Pa or less. Vent equipped with a twin-screw, three-stage type screw (PET and PPS kneading plasticization zone / Dalmerization kneading zone / Fine dispersion compatibilization zone by reverse screwing Dalmage) heated to 280-320 ° C. after drying for a period of time This was fed to a twin screw extruder (L / D = 40, vent vacuum 200 Pa), melt extruded with a residence time of 3 minutes, and PPS / PET master pellets containing 3% by weight of PET were obtained.

  Subsequently, the obtained PPS / PET master pellets were dried under reduced pressure at 180 ° C. for 3 hours, and then supplied to a full flight single screw extruder in which an extruder melting portion was heated to 290 ° C. The molten polymer is passed through a fiber sintered stainless metal filter (14 μm cut), then melt extruded from a die of a T die set at a temperature of 285 ° C., and an electrostatic charge is applied to a cast drum having a surface temperature of 25 ° C. The film was tightly cooled and solidified to produce an unstretched film. This unstretched film was stretched at a magnification of 3.4 times in the longitudinal direction of the film at a temperature of 98 ° C. using a difference in peripheral speed of the roll using a longitudinal stretching machine composed of a plurality of heated roll groups. . Then, the both ends of this film are gripped with clips, guided to a tenter, stretched in the width direction of the film at a stretching temperature of 100 ° C. and a stretching ratio of 3.5 times, and subsequently heat treated at a temperature of 250 ° C. for 8 seconds. Thereafter, the film was subjected to a 5% relaxation treatment in the transverse direction in a cooling zone controlled at 160 ° C. and cooled to room temperature, and then the film edge was removed to obtain a biaxially oriented film having a thickness of 125 μm. The configuration and characteristics of the biaxially oriented film obtained in this example are as shown in Table 3, and the fluidity is improved from the value of the melt viscosity as compared with Example 1, and even at a melt extrusion temperature of 290 ° C. Stable melt extrusion and film formation are possible, and the film properties have the same level of flame retardancy and thermal dimensional stability as in Example 1, and the molding processability is superior to that in Example 1. It was.

(Example 10)
3% by weight of the PET resin obtained in Reference Example 2 and 97% by weight of the m-PPS resin obtained in Reference Example 3 were dried at 150 ° C. and a reduced pressure of 133 Pa or less for 4 hours, respectively, and then heated to 280 to 320 ° C. Vent type twin screw extruder (L / D = 40, equipped with a twin screw / three stage type screw (configuration of PET and PPS kneading plasticization zone / dull mage kneading zone / inverted screw dull mage). (Vent vacuum 200 Pa) and melt extrusion with a residence time of 3 minutes to obtain a PPS / PET master pellet containing 3 wt% of PET.

  Next, the obtained PPS / PET master pellets were dried under reduced pressure at 180 ° C. for 3 hours, and then supplied to a full flight single screw extruder whose extruder melted portion was heated to 280 ° C. The molten polymer is passed through a fiber sintered stainless metal filter (14 μm cut), then melt extruded from a die of a T die set at a temperature of 280 ° C., and an electrostatic charge is applied to a cast drum having a surface temperature of 25 ° C. The film was tightly cooled and solidified to produce an unstretched film. This unstretched film was stretched at a magnification of 3.4 times in the longitudinal direction of the film at a temperature of 90 ° C. using a difference in peripheral speed of the roll using a longitudinal stretching machine composed of a plurality of heated roll groups. . Thereafter, both ends of the film are gripped with clips and guided to a tenter, stretched in the width direction of the film at a stretching temperature of 95 ° C. and a stretching ratio of 3.5 times, and subsequently subjected to heat treatment at a temperature of 245 ° C. for 8 seconds. Thereafter, the film was subjected to a 5% relaxation treatment in the transverse direction in a cooling zone controlled at 160 ° C. and cooled to room temperature, and then the film edge was removed to obtain a biaxially oriented film having a thickness of 125 μm. The composition and characteristics of the biaxially oriented film obtained in this example are as shown in Table 3. Compared to Example 1, the fluidity is greatly improved from the melt viscosity value, and the melt extrusion temperature of 280 ° C. Also, stable melt extrusion and film formation were possible, and in the film characteristics, the same flame retardance as in Example 1 was obtained, and the molding processability was superior to that in Example 1. Although the thermal dimensional stability was slightly inferior, there was no problem.

  Films for various industrial materials such as electric insulation, solar cells, packaging, ink ribbons, circuit boards, condensers, and more specifically, electric insulation materials for water heater motors and car air conditioners used in hybrid vehicles It can be suitably used as an electrical insulating material for a motor for a motor, a drive motor, etc., or as a film for a solar battery back sheet or a circuit board used for bonding with a different material.

Claims (5)

The polyphenylene sulfide resin contains a polyester resin having an ethylene terephthalate unit as a main component in an amount of 0.1% by weight to 8% by weight when the sum of the weight of the polyphenylene sulfide resin and the weight of the polyester resin is 100% by weight. And a biaxially oriented polyphenylene sulfide film having a breaking elongation in the width direction of 70% or more. 2. The biaxial orientation according to claim 1, wherein the content of the polyester resin is 0.5 wt% or more and less than 5 wt% when the sum of the weight of the polyphenylene sulfide resin and the weight of the polyester resin is 100 wt%. Polyphenylene sulfide film. The biaxially oriented polyphenylene according to claim 1 or 2, wherein the sum of the heat shrinkage ratios in the longitudinal direction and the width direction of the film when the heating condition is 150 ° C for 30 minutes is 2.5% or less. Sulfide film. The copolymerized polyphenylene sulfide resin is contained in the polyphenylene sulfide resin in an amount of 30% by weight or more when the sum of the weight of the polyphenylene sulfide resin and the weight of the polyester resin is 100% by weight. A biaxially oriented polyphenylene sulfide film according to claim 1. Both resins are mixed so that the polyester resin containing a polyphenylene sulfide resin and an ethylene terephthalate unit as a main component is contained in an amount of 0.1 to 8% by weight when the sum of the weight of the polyphenylene sulfide resin and the weight of the polyester resin is 100% by weight. A step of melt-extruding the mixed resin at a maximum heating temperature of 300 ° C. or less during melt extrusion, a step of biaxially stretching the melt-extruded film in the longitudinal direction and the width direction, and after biaxial stretching Performing a heat setting of at a temperature of 240 ° C. or higher and 280 ° C. or lower, and a method for producing a biaxially oriented polyphenylene sulfide film.