JP2021088174A - Polyphenylene sulfide film, roll of polyphenylene sulfide film, and method of manufacturing the same - Google Patents

Abstract

To provide a polyphenylene sulfide film containing very little polyphenylene sulfide modified polymer, and a film roll.SOLUTION: There is provided a polyphenylene sulfide film in which, in a film plane, a maximum wavelength of a fluorescence spectrum is not observed in a wavelength region of 450 nm or more.SELECTED DRAWING: None

Description

The present invention relates to a polyphenylene sulfide film having an extremely small amount of modified polymer mainly composed of a resin raw material constituting the film on the surface of the film, a roll made of the polyphenylene sulfide film, and a method for producing the same.

As electronic devices and information devices become more sophisticated and more accurate, the required quality of materials used is becoming stricter. For example, the required quality of base film for capacitors, substrate film for high frequency circuits, and release film is strict. These members often require processing such as bonding other materials to the base film or coating.

Therefore, it is desired that there are few surface defects and internal defects of the base film so as not to impair the quality of the above members, and at the same time, in order to improve workability during processing, heat resistance, chemical resistance and dimensional stability are desired. , Good mechanical properties are required.

Films such as polyethylene, polypropylene, polyester, polyimide, and fluororesin have been used as films and sheets conventionally used in the above fields. Among them, polyphenylene sulfide film has heat resistance, chemical resistance, and dimensional stability. Since the mechanical properties are good, it can be suitably used and the range of use is expanded. Among them, as an example of providing a high-quality polyphenylene sulfide film, a polyphenylene sulfide film having few surface defects has been proposed (Patent Document 1).

Japanese Patent Application Laid-Open No. 2000-34356

Polyphenylene sulfide film has good heat resistance, chemical resistance, dimensional stability, and mechanical properties, so it is suitable for high-performance electronic equipment members. However, when polyphenylene sulfide film contains locally modified products. Is a chronic issue. Since the modified polyphenylene sulfide has different resin properties from that of polyphenylene sulfide, it may induce a shape change or perforation around the modified product during the film forming process, which may impair the quality of the film. However, since an analytical method capable of distinguishing between polyphenylene sulfide modified products and polyphenylene sulfide has not been found, the identity and cause of the modified products cannot be identified, and a method capable of suppressing the formation of the modified products has not been established.

The present invention provides a polyphenylene sulfide film, a polyphenylene sulfide film roll, and a method for producing the same, which are characterized by having extremely few defects due to a modified polymer containing the same as a main component in the resin raw material constituting the film and having good flatness. To provide.

In order to solve the above problems, the present invention has the following configuration. That is,
[1] A polyphenylene sulfide film characterized in that the maximum wavelength of the fluorescence spectrum is not observed in a wavelength region having a wavelength of 450 nm or more in the film surface.
[2] The cross-section of the film was measured 4096 by infrared spectroscopy (ATR method), a peak intensity peak intensity in the wavelength range of 1200～1250Cm ^-1 and (IR-p) in the wavelength range of 1450～1500Cm ^-1 A polyphenylene sulfide film in which the ratio of the ratio X to 0.01 or less is 0.5 or more when the ratio X [(IR-p) / (IR-s)] of (IR-s) is determined.
[3] The polyphenylene sulfide film according to [1] or [2], wherein the thickness of the film is 1.0 μm or more and 500 μm or less.
[4] A polyphenylene sulfide film roll obtained by winding a polyphenylene sulfide film, characterized in that a maximum wavelength of a fluorescence spectrum is not observed in a wavelength region having a wavelength of 450 nm or more in the film surface.
[5] a cross-section of the film was measured 4096 by infrared spectroscopy (ATR method), a peak intensity at a range of a peak intensity (IR-p) and wavelength 1450～1500Cm ^-1 in the wavelength range of 1200～1250Cm ^-1 When the ratio X [(IR-p) / (IR-s)] of (IR-s) was determined, the polyphenylene sulfide film having a ratio X of 0.01 or less was 0.5 or more was wound up. Polyphenylene sulfide film roll.
[6] The polyphenylene sulfide film roll according to [4] or [5], wherein the thickness of the film is 1.0 μm or more and 500 μm or less.
[7] The description according to any one of [4] to [6], wherein the width of the film roll is 300 mm or more, and the length of the polyphenylene sulfide film wound on the roll is 500 m or more. Polyphenylene sulfide film roll.
[8] The polyphenylene sulfide film roll according to any one of [4] to [7], wherein the orientation angle of the film roll is 85 degrees or less with respect to the longitudinal direction of the film.
[9] The polyphenylene sulfide film resin composition is put into an extruder, melt-kneaded in the extruder, extruded from a mouthpiece to be cooled and solidified, and then stretched at least in the traveling direction of the film. The method for producing a polyphenylene sulfide film according to any one of [1] and [3], wherein the oxygen concentration in the mouthpiece is 1.0% by volume or less.
[10] The polyphenylene sulfide resin composition is charged into an extruder, melt-kneaded in the extruder, and then extruded from a mouthpiece for a resin residence time of less than 120 minutes [9]. ] The method for producing a polyphenylene sulfide film according to the above.
[11] The polyphenylene sulfide film resin composition is put into an extruder, melt-kneaded in the extruder, extruded from a mouthpiece to be cooled and solidified, and then stretched at least in the traveling direction of the film. The method for producing a polyphenylene sulfide film roll according to [4] to [8], wherein the oxygen concentration in the mouthpiece is 1.0% by volume or less.
[12] The polyphenylene sulfide resin composition is charged into an extruder, melt-kneaded in the extruder, and then extruded from a mouthpiece for a resin residence time of less than 120 minutes [11]. ]. The method for producing a polyphenylene sulfide film roll.

According to the present invention, it is possible to provide a polyphenylene sulfide film and a polyphenylene sulfide film roll in which the amount of modified polymer containing a resin raw material constituting the film as a main component is extremely small.

The polyphenylene sulfide in the present invention refers to a polymer in which 85 mol% or more (preferably 90 mol% or more) of repeating units is composed of structural units represented by the following structural formulas. If such a component is less than 85 mol%, the crystallinity, softening point, etc. of the polymer may be lowered, and the heat resistance, dimensional stability, mechanical properties, mold releasability, etc. may be impaired.
Chemical formula 1

In the above polyphenylene sulfide, if it is less than 15 mol%, preferably less than 10 mol% of the repeating unit, a unit containing a copolymerizable sulfide bond may be included as the repeating unit. The method of copolymerizing the polymer may be random or block type.

In the present invention, the PPS film refers to a film in which 90% by weight or more of the resins constituting the film is PPS.

One aspect of the present invention is a polyphenylene sulfide film in which the maximum wavelength of the fluorescence spectrum is not observed in the wavelength region of 450 nm or more in the film plane. By using such a polyphenylene sulfide film, it is possible to obtain a film in which the amount of the modified polymer containing the resin constituting the film as a main component is extremely small. Fluorescence intensity peaks of such modified polymers are observed above 450 nm. This modified polymer is produced by modifying the polyphenylene sulfide resin, and as a result of diligent studies by the present inventors, the polyphenylene sulfide resin in which the polyphenylene sulfide resins are oxygen-bridged and the sulfur of the polyphenylene sulfide resin are obtained. It was found to be one of the polyphenylene sulfide resins with a sulfonyl group whose atoms were oxidized. Further, since these modified sites have different resin properties from polyphenylene sulfide, deformation of the peripheral portion in the film forming process, especially when the film is a thin film, is caused by thickness unevenness, and conversely, the thin film is formed. Therefore, it may induce perforation and significantly impair the quality of the film. As a result of diligent studies by the present inventors, it has been found that the modified polymer of the polyphenylene sulfide resin is produced particularly during the step of drying the resin before film formation or during melt extrusion during film formation. It is important to manage these modified polymers as modified sites in the film. For example, unlike unmelted polyphenylene sulfide resin due to insufficient melting and iron powder due to friction of manufacturing machines generated in the film forming process, these foreign substances are observed and managed with a maximum wavelength of fluorescence spectrum of 450 nm or more. be able to.

This modified site does not contain inorganic substances such as SUS and is composed only of resin.

Further, as another aspect of the present invention, in the measurement method described later, 4096 points of the cross section of the film are measured by infrared spectroscopic analysis (ATR method), and the peak intensity (IR- ^{) in the wavelength range of 1200 to 1250 cm -1 is measured.} When the ratio X [(IR-p) / (IR-s)] of p) and the peak intensity (IR-s) in the wavelength range of 1450 to 1500 cm ^{-1 is determined, the ratio X is 0.01 or less.} The ratio is 0.5 or more. By using such a polyphenylene sulfide film, it is possible to obtain a film having an extremely small amount of modified polymer in the film. When the cross section of the film is measured by infrared spectroscopic analysis (ATR method), the above-mentioned modified polymer is ^{observed in the wavelength range of 1200 to 1250 cm-1} (peak derived from (oxygen cross-linking, sulfonic acid component)). The unmodified polyphenylene sulfide resin is ^{observed in the wavelength range of 1450 to 1500 cm -1} (peak derived from (aromatic ring C = C expansion and contraction)). In the film cross-section, the ratio X of the peak intensity in the wavelength range of 1200～1250Cm ^-1 peak intensity in the range of (IR-p) and wavelength ^{1450~1500cm -1 (IR-s) [} (IR-p) / (IR- By having many portions of 0.01 or less in s)], it is possible to obtain a film in which the modified polymer is extremely small in the film. More preferably, the ratio at which the ratio X is 0.01 or less is 0.6 or more.

The polyphenylene sulfide film of the present invention preferably has a thickness of 1.0 μm or more and 500 μm or less, and more preferably 250 μm or less. If the film thickness is less than 1.0 μm, the film breaking strength and breaking elongation may be significantly lowered, and the workability may be deteriorated. If the film thickness is larger than 500 μm, burrs are likely to occur during film processing, which may make handling difficult. By setting the film thickness within the above range, it is possible to obtain a film having good breaking strength and breaking elongation and suppressing the generation of burrs during film processing.

One aspect of the present invention is a polyphenylene sulfide film roll obtained by winding a polyphenylene sulfide film, which is characterized in that a maximum wavelength of a fluorescence spectrum is not observed in a wavelength region of 450 nm or more in the film plane.

The polyphenylene sulfide film roll of the present invention preferably has a width of 300 mm or more. It may be an intermediate product roll that is wound immediately after the film is manufactured, or it may be a product roll that is formed by slitting the intermediate product roll. The length of the polyphenylene sulfide film wound on the polyphenylene sulfide film roll is preferably 500 m or more, more preferably 1000 m or more. The longer the film length, the easier it is for the molten resin to stay. Therefore, especially when the film length is 1000 m or more, the conventional polyphenylene sulfide film roll has a metamorphic site, but the polyphenylene sulfide film of the present invention has a metamorphic site. Since it has the effect of suppressing the degeneration site, it is unlikely to cause defects.

The polyphenylene sulfide film wound on the polyphenylene sulfide film roll of the present invention is particularly effective in suppressing a modified portion when the orientation angle is 85 degrees or less with respect to the longitudinal direction of the film. As described above, when the residence time in the film manufacturing process becomes long, the film manufacturing process usually has a rectangular shape in the width direction perpendicular to the film forming direction while filtering the molten resin with a cylindrical filter. The molten resin is extruded from the base die, but the flow speed of the outer periphery of the filter is more likely to stagnate than the flow speed of the central part of the filter, and the resin transported to the rectangular base die is Since the amount of resin retained at the end portion is large, a modified portion is more likely to occur in the end portion direction with respect to the film width direction. Therefore, the modified resin is likely to be generated at a portion where the orientation angle is 85 degrees or less with respect to the longitudinal direction of the film.

The polyphenylene sulfide film of the present invention preferably contains particles for the purpose of enhancing the slipperiness of the film. As the type of particles, particles that do not affect the fluorescence spectrum of the polyphenylene sulfide film of the present invention can be used. One type of particles may be used alone, or two or more types may be used in combination. Among the particles, calcium carbonate particles are preferable because they have good dispersibility in the polyphenylene sulfide film.

The average particle size of the particles contained in the polyphenylene sulfide film of the present invention is preferably 0.1 μm or more and 10 μm or less, more preferably 5 μm or less, and further preferably 2 μm or less. If the average particle size is larger than 10 μm, the film surface protrusions become large, so that it may not be suitable for mold release applications. If the average particle size is less than 0.1 μm, the slipperiness of the film surface deteriorates, so that scratches are likely to occur during film transportation and processing, and the quality of the film may deteriorate.

The content of the particles contained in the polyphenylene sulfide film of the present invention is preferably 0.1% by weight or more and 5% by weight or less, and more preferably 3% by weight or less. If the particle content is larger than 5% by weight, the film surface protrusions become large, so that it may not be suitably used for mold release applications and the like. If the particle content is less than 0.1% by weight, the slipperiness of the film surface deteriorates, so that scratches are likely to occur during film transportation and processing, and the quality of the film may deteriorate.

The polyphenylene sulfide film of the present invention may be blended with a resin (different polymer) other than polyphenylene sulfide as long as it does not adversely affect the fluorescence spectrum of the present invention, and may be blended with an antioxidant, a heat stabilizer, and a lubricant. , An additive such as an ultraviolet absorber may be added.

The polyphenylene sulfide film of the present invention may be a single film or a composite film. Examples of the composite film include a laminated film having two or more layers. For example, the polyphenylene sulfide film of the present invention may be a two-layer laminated film composed of A layer / B layer having a surface layer (A layer) or a three-layer laminated film composed of A layer / B layer / A layer, and may be a flat surface. From the viewpoint of properties and withstand voltage, it is preferable to apply the polyphenylene sulfide film of the present invention to all layers.

The surface of the polyphenylene sulfide film of the present invention may be coated or laminated with a resin or compound such as an antistatic agent as long as it does not adversely affect the fluorescence spectrum of the present invention, or an appropriate surface treatment such as corona discharge treatment may be applied. Or plasma treatment.

(Film manufacturing method)
Regarding the method for producing a polyphenylene sulfide film of the present invention, it is preferable to produce it by, for example, the steps shown below.

First, the method for producing polyphenylene sulfide of the present invention will be described. Polyphenylene sulfide can be produced, for example, by polymerizing an alkali metal sulfide (alkali sulfide) with dihalobenzene.

Examples of the alkali metal sulfide include lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, cesium sulfide and the like, and among them, sodium sulfide is preferable. These alkali metal sulfides can be used as hydrates or aqueous mixtures, or in the form of anhydrides. It is also possible to use alkali metal sulfides, sulfides, alkali metal hydrates such as lithium hydroxide and sodium hydroxide prepared in situ and alkali metal sulfides prepared from hydrogen sulfide in the reaction system. it can. One type of alkali metal sulfide may be used alone, or two or more types may be used in combination.

Examples of dihalobenzene include p-dichlorobenzene such as p-dichlorobenzene and p-dibromobenzene, m-dihalobenzene such as m-dichlorobenzene, and halogen atoms such as 1-methoxy-2,5-dihalobenzene and 3,5-dichlorobenzoic acid. Dichlorobenzene and the like containing a substituent other than the above can be mentioned. Among these, p-dichlorobenzene is preferable, and p-dichlorobenzene is particularly preferable. One type of dihalobenzene may be used alone, or two or more types may be used in combination.

The amount of dihalobenzene used (charged amount) is preferably in the range of 0.9 to 2.0 mol, more preferably 1.0 to 1.3 mol, per 1 mol of charged alkali metal sulfide. Desirable for obtaining polyphenylene sulfide. If this usage ratio is less than 0.9 mol or more than 2.0 mol, it becomes difficult to obtain polyphenylene sulfide having a high viscosity (high degree of polymerization) suitable for processing, which is not preferable.

In the present invention, a monohalo compound (not necessarily an aromatic compound) can be used in combination with dihalobenzene in order to form the terminal of the produced polyphenylene sulfide, or to regulate the polymerization reaction or the molecular weight. Further, in order to form a branched or crosslinked polymer, a polyhalo compound (not necessarily an aromatic compound) having a trihalo or higher such as 1,2,4-trichlorobenzene or 1,3,5-trichlorobenzene, or an active hydrogen is used. It is also possible to use a halogen aromatic compound, a halogen aromatic nitro compound and the like in combination.

In the present invention, it is preferable to add a polymerization aid to react in order to adjust the degree of polymerization. As the polymerization aid, a known polymerization aid generally used as a polymerization aid for polyphenylene sulfide can be used. For example, alkali metal hydroxide (caustic alkali), carboxylic acid alkali metal salt, alkali metal carbonate, etc. Examples include alkaline earth metal hydroxides and alkaline earth metal carbonates. Among these, alkali metal hydroxides and carboxylic acid alkali metal salts are preferably used.

Examples of the alkali metal hydroxide include sodium hydroxide, potassium hydroxide, lithium hydroxide and the like. Examples of the alkali metal salt of the carboxylic acid include lithium acetate, sodium acetate, potassium acetate, sodium propionate, lithium valerate, sodium benzoate, sodium phenylacetate, potassium p-tolurate, and the like, which are inexpensive. Sodium acetate is preferably used because it is easily available. Alkali metal salts of carboxylic acids can be used as anhydrides, hydrates or aqueous solutions. Further, the alkali metal salt of the carboxylic acid is composed of an organic acid and one or more compounds selected from the group consisting of an alkali metal hydroxide, an alkali metal carbonate and an alkali metal bicarbonate in an organic amide solvent. It may be formed by adding equal chemical equivalents and reacting.

One type of polymerization aid may be used alone, or two or more types may be used in combination. The amount of the polymerization aid used can be appropriately selected from a wide range depending on the type of the polymerization aid itself, the type of alkali metal sulfide and dihalobenzene, etc., but is 0 with respect to 1 mol of the charged alkali metal sulfide. The range of 0.01 mol to 5 mol is preferable, and the range of 0.1 to 2 mol is more preferable.

As the solvent, it is preferable to use a polar solvent such as an organic amide solvent. Among the organic amide solvents, N-alkylpyrrolidone such as N-methyl-2-pyrrolidone and N-ethyl-2-pyrrolidone, and caprolactams such as N-methyl-ε-caprolactam, 1 , 3-Dialkyl-2-imidazolidinone, tetraalkylurea, amide-based high boiling point polar solvent such as abrotic organic amide solvent typified by hexaalkylphosphate triamide is preferably used. Among these, N-methyl-2-pyrrolidone (hereinafter, may be abbreviated as NMP) is particularly preferably used. The amount of the solvent used is preferably in the range of 0.2 to 10 mol, more preferably in the range of 2 to 5 mol, per 1 mol of the charged alkali metal sulfide.

(1) The polyphenylene sulfide used in the polyphenylene sulfide film of the present invention contains an appropriate amount of alkali metal sulfide and dihalobenzene, and if necessary, an appropriate amount of a halogenating compound other than dihalobenzene and a polymerization aid, such as an amide-based high boiling point solvent. It can be produced by adding it to the polar solvent of the above and reacting it under high temperature and high pressure. The pressure in the polymerization system is appropriately selected according to the type and amount of the auxiliary agent used, the desired degree of polymerization, and the like. The temperature and polymerization time in the polymerization system are also appropriately selected depending on the type and amount of the auxiliary agent used, the desired degree of polymerization, etc., but are preferably 20 minutes to 50 hours at a temperature of 200 to 300 ° C. It is preferably 1 to 10 hours at a temperature of 230 to 280 ° C. As described above, powdery or granular polyphenylene sulfide is obtained. The resulting powdery or granular polyphenylene sulfide is then washed with water and / and a solvent to separate by-salts, polymerization aids, unreacted monomas and the like.

(2) When particles are added to the polyphenylene sulfide film of the present invention as described above, first, the particles are mixed with the powdery or granular polyphenylene sulfide obtained in (1) above, and uniformly mixed with Henschel or the like. Further, when blending a resin (different polymer) other than polyphenylene sulfide, or when adding additives such as an antioxidant, a heat stabilizer, a lubricant, and an ultraviolet absorber, the mixture is similarly mixed with polyphenylene sulfide.

Then, the obtained mixture is supplied to an extruder (preferably an extruder having one or more stages of vent holes), melt-kneaded at a temperature of 290 to 360 ° C., and extruded from a suitable mouthpiece to obtain a polyphenylene sulfide resin composition. obtain. Further, it may be melt-molded into a gut shape and cut to a length of about 2 to 10 mm to obtain a pellet-shaped polyphenylene sulfide resin composition. The obtained polyphenylene sulfide resin composition is dried in a heating type dryer under vacuum at a temperature of 100 to 180 ° C. and a time of about 1 to 5 hours.

When particles are not added, a resin (different polymer) other than polyphenylene sulfide, an antioxidant, a heat stabilizer, a lubricant, an ultraviolet absorber, etc. is added to the polyphenylene sulfide obtained in (1) as necessary. The agents can be mixed and extruded or melt molded in the same manner as in the case of a mixture containing particles, and used as a polyphenylene sulfide resin composition.

The polyphenylene sulfide resin composition produced in this manner may be used alone or in combination of two or more. For example, polyphenylene sulfide resin pellets to which particles have been added (hereinafter, also referred to as particle pellets) and polyphenylene sulfide resin pellets to which particles have not been added (hereinafter, also referred to as particle-free pellets) can be mixed and used.

(3) Next, the polyphenylene sulfide resin pellet of the present invention is produced using the polyphenylene sulfide resin pellet obtained in (2). The polyphenylene resin pellet obtained in (2) is stirred with a mixer under reduced pressure (preferably with a vacuum degree of 0 to 50 mmHg) to a temperature of 120 to 230 ° C. (preferably 160 ° C. to 200 ° C.) for 3 hours. The above (preferably 5 to 10 hours) is dried. The polyphenylene sulfide resin composition may be dried in a plurality of steps, such as drying the polyphenylene sulfide resin composition as described above, then slowly cooling the composition, returning it to room temperature, and drying it again. Here, if the drying temperature exceeds 230 ° C., there is a concern that the dried raw material will solidify and hinder the film formation of the film, and if the temperature is less than 120 ° C., impurities in the polyphenylene sulfide raw material, particularly about 250 ° C. High boiling point compounds that are heated to the point of volatilization may remain, causing film defects. Insufficient depressurization causes the polyphenylene sulfide resin to react with oxygen, facilitating the formation of modified polymers.

Next, the dried polyphenylene sulfide resin composition is used to prepare the polyphenylene sulfide film of the present invention, and the film may be a single layer or a composite layer. When the composite film is produced, a coating, laminating, coextrusion method or the like can be used as the laminating method. Among them, lamination by coextrusion is preferable in terms of controlling the thickness of each layer constituting the polyphenylene sulfide film of the present invention.
The polyphenylene sulfide film of the present invention is formed as follows. First, the polyphenylene sulfide resin composition is supplied to a melt extruder and heated to a temperature equal to or higher than the melting point (preferably 290 to 360 ° C.) of the polyphenylene sulfide resin composition to melt it. Next, the melt is extruded from a slit-shaped mouthpiece outlet and rapidly cooled by a method such as cooling and solidifying (casting) on a rotating metal drum called a casting roll to prepare an unstretched film. At this time, it is preferable to install a gear pump, a static mixer, and a filtration device in the polymer flow path. When this melt extrusion time is long, the polyphenylene sulfide resin has an increased chance of reacting with residual oxygen, which increases the possibility of oxygen cross-linking or sulfonated, that is, forming a modified polymer. In the filtration device, the resin tends to stay in the vicinity of the outer wall on the inner surface of the casing, so that the chances of the polymer being modified increase, and it becomes easy to be observed as a modified polymer in the finally obtained film.

The residence time during melting of the resin (the time from when the polyphenylene sulfide resin composition is put into the extruder, after being melt-kneaded in the extruder, and then extruded from the mouthpiece) shall be less than 120 minutes. Is preferable, and more preferably less than 90 minutes. For the purpose of the present invention, it is not necessary to set a lower limit of the residence time in particular, but it is realistic that it is 10 minutes or more in order to prevent insufficient melting. Further, as the film thickness becomes thinner, the amount of molten polymer discharged decreases in the film forming process described later, so that the residence time in the extrusion system tends to increase. As a method of shortening the residence time, increasing the film forming speed can be mentioned, but the amount of heat may be insufficient in the film heat treatment step, and the dimensional stability deteriorates in the post-processing of applying heat to the film. Therefore, in the present invention, a method of controlling the residence time and suppressing the generation of the modified polymer can be mentioned as a preferable method.

The polyphenylene sulfide film of the present invention preferably has an oxygen concentration of 1.0% by volume or less in the mouthpiece from the extruder. When the oxygen concentration in the mouthpiece from the extruder is greater than 1.0% by volume, the sulfur atom of the polyphenylene sulfide resin reacts with oxygen to promote the sulfonated polyphenylene sulfide, or the polyphenylene sulfides are crosslinked with oxygen. In some cases, modified polymers are likely to be produced. The reason why the oxygen concentration becomes larger than 1.0% by volume is that the air remaining in the gap between the pellets is contained in the extruder as it is. In order to reduce the oxygen concentration in the mouthpiece from the extruder to 1.0% by volume or less, when the pellets are vacuum-dried and then the pressure in the system is equalized, an inert gas such as nitrogen gas, argon gas, or helium gas is used. There is a method of inflowing gas. Among the inert gases, the high-purity gas has a greater effect of suppressing the formation of the modified polymer.

A step of stretching the obtained unstretched film in the film longitudinal direction (sometimes referred to as a vertical direction or a running direction of the film) and a step of stretching in the film width direction (horizontal direction) using a roll group and a tenter. Examples thereof include a sequential biaxial stretching method and a simultaneous biaxial stretching method in which stretching in the film longitudinal direction and the film width direction is performed at the same time. Among them, the sequential biaxial stretching method is preferable.

When the sequential biaxial stretching method is used, the stretching conditions are appropriately selected from a wide range according to various conditions such as the type of polyphenylene sulfide contained in the polyphenylene sulfide resin composition and the presence / absence and type of other resins and additives. However, the temperature is 60 to 150 ° C., preferably 70 to 130 ° C., more preferably 80 to 110 ° C., and the longitudinal direction (longitudinal direction) and the width direction (horizontal direction) are each 2 to 7 times, preferably 2 It is preferable to stretch at a magnification of ~ 5 times, more preferably 3 to 5 times.

It is preferable that the obtained stretched film is further heat-treated. The heat treatment conditions at this time can be appropriately selected from a wide range depending on the type of polyphenylene sulfide contained in the polyphenylene sulfide resin composition and various conditions such as the presence / absence and type of other resins and additives, but the temperature. It may be carried out in the range of 180 to (melting point of polyphenylene sulfide composition) ° C., preferably 200 to (melting point of polyphenylene sulfide resin composition-5) ° C. for 1 to 60 seconds under a constant length or a limited shrinkage of 15% or less. , Preferable in terms of heat resistance, mechanical properties, and thermal dimensional stability. Further, in order to improve the thermal dimensional stability of the film, it may be relaxed in one direction or two directions.

The polyphenylene sulfide film thus obtained can be used for various types of industrial use, and since it has the electrical conductivity characteristic of the polyphenylene sulfide resin, it can be particularly preferably used for capacitors and mold release applications.

(Measurement method of physical properties)
(1) Collection of rolls to be evaluated While rewinding the intermediate product rolls obtained from each Example / Comparative Example, slits of 200 mm in the width direction from the center of the intermediate product roll and 400 mm from the cross section to both ends, for a total of 5 rolls. It was made into a film roll. In the obtained film roll, the first, third, and fifth rolls are measured from one (left) end to the other (right) end of the intermediate product roll.
For convenience, the first measurement target is "-1", the third is "-2", and the fifth is "-3". That is, in Example 1, the first (left end) is used. Examples 1-1, the third (center portion) is referred to as Example 1-2, the fifth (right end portion) is referred to as Example 1-3, and so on, and the same applies to other Examples and Comparative Examples. ..

(2) Number of Modified Sites and Fluorescence Intensity Each film roll obtained at the extreme wavelength (1) is divided into three equal parts in the longitudinal direction, and within each of the three equal parts, 500 × in the longitudinal direction from any location. Cut out to 500 mm and use samples A, B, and C in order from the unwinding direction. Among the samples A, B, and C, the defect points that can be visually confirmed in the sample are specified, the one having the most defects is designated as the observation sample D, and if no defects are confirmed, the sample A is designated as the observation sample D. When a plurality of defects in the observed sample D are confirmed in a 10 mm square centering on an arbitrary defect portion, the defects in the sample are confirmed as one. Using a fluorescence microscope "BX-51" (manufactured by Olympus Medical Science Co., Ltd.) and a spectroscopic unit "TFCAM-7000 / F" (manufactured by Lambda Vision Co., Ltd.), the drawbacks are the wavelength region on the X-axis and the wavelength on the Y-axis. As a spectrum, the wavelength spectrum that maximizes all the defects was obtained. Among the obtained wavelength spectra, the wavelength having the maximum wavelength spectrum of 450 nm or more was set as the intensity limit wavelength, and the defect was set as the denatured site, and the number of denatured sites was counted.

(3) Infrared spectroscopy (ATR method)
A cross section of a defect measured with a fluorescence microscope in the observation sample D in (2) was cut out, and 64 × 64 points (4096) in a 32 μm square region were used with a micro-PL spectroscopic analyzer “HR-320” (manufactured by Horiba Jobin Yvon). Point), infrared spectroscopic analysis was performed by the ATR method, and data was collected by a two-dimensional infrared detector. The peak observed at 1200 to 1250 cm ^-1 was defined as a peak derived from modified PPS (oxygen cross-linked, sulfonic acid component), and its intensity was defined as IR-p. The peak observed at 1450 to 1500 cm ^-1 was defined as a peak derived from PPS (aromatic ring C = C expansion and contraction), and its intensity was defined as IR-s. Regarding the ratio X [(IR-p) / (IR-s)] of 4096 points, the ratio of the ratio X ≦ 0.01 was defined as A, and the ratio of the ratio X> 0.01 was defined as B.
In the case of a laminated film, ATR measurement was performed for each layer.
Regarding IR-s, the peak position did not change even if a resin other than PPS was mixed in an amount of about several% by weight. Therefore, the peak observed at ^{1450 to 1500 cm -1 was defined as IR-s.}

(4) Thickness (μm)
From the observation sample D obtained in (2), a slice of a film whose cross section was cut using an electric microtome ST-201 manufactured by Japan Microtome Research Institute was observed with a transmitted light microscope, and the thickness (μm) was measured.

(5) Orientation angle Using the microwave transmission type molecular orientation meter MOA-6004 (manufactured by Oji Measuring Instruments Co., Ltd.) from the observation sample D obtained in (2), the edge of the film roll is 20 mm from the center to the center. 300 × 300 mm in the longitudinal direction was cut out toward, and the orientation angle from the longitudinal direction was measured.

(6) Film-forming stability In film-forming, the film-forming stability was evaluated as follows.
Good ◎: Passed when film tear is less than 1 time / 2 days 〇: Passed when film tear is 1 time / 2 days or more and less than 1 day ×: When film tear occurs once / 1 day or more ..

(7) Flatness Arbitrary two points were selected from the parts of the observed sample D for which no defects were confirmed, the cross-sectional height was confirmed by SEM, and the average was taken as the film thickness A. In addition, the same applies to the sites identified as denatured sites of the sample used in (1) (any three denatured sites are targeted for measurement, and if there are less than three denatured sites, only the existing number is measured). The cross-sectional height was confirmed by SEM and averaged to obtain the thickness B of the film in which the denatured portion exists, the absolute value of the difference in thickness | thickness A-thickness B | was obtained, and the flatness of the film was evaluated as follows. ..

Good ⊚: 1.0% ≧ | Thickness A-Thickness B | / Thickness A × 100
Pass 〇: 1.5% ≧ | Thickness A-Thickness B | / Thickness A x 100> 1.0%
Fail x: | Thickness A-Thickness B | / Thickness A x 100> 1.5%.

(8) Comprehensive evaluation The comprehensive evaluation of the film was evaluated in the following three stages from the viewpoint of film forming stability and flatness.
⊚: Both film-forming stability and flatness are good 〇: Both film-forming stability and flatness are passed or good, and any one or more is passed ×: One or more of film-forming stability and flatness failure.

[Manufacturing of film]
(Manufacturing method of polyphenylene sulfide powder)
In a 70 L autoclave with a stirrer, 8.181 kg (70.00 mol) of 48 wt% sodium hydroxide aqueous solution, 2.943 kg (70.63 mol) of 96% pure sodium hydroxide, N-methyl-2-pyrrolidone. 11.45 kg (115.5 mol) of (NMP), 2.239 kg (27.30 mol) of anhydrous sodium acetate, and 4.900 kg (272.2 mol) of ion-exchanged water were charged, and 240 ° C. was passed through nitrogen at normal pressure. The reaction vessel was cooled to 160 ° C. after distilling 9.12 kg of water and 0.14 kg of NMP. The stirring speed in this reaction was 240 rpm (240 rpm).

The amount of residual water in the system per 1 mol of the charged alkali metal sulfide was 72.0 mol including the water consumed for the hydrolysis of NMP. In addition, 0.020 mol of hydrogen sulfide per mol of the charged alkali metal sulfide was scattered outside the reaction system.

Next, 10.29 kg (69.97 mol) of p-dichlorobenzene (p-DCB) and 9.090 kg (91.70 mol) of NMP were added to the reaction system. After sealing the reaction vessel under nitrogen gas, the temperature was raised from 200 ° C. to 227 ° C. at a rate of 0.8 ° C./min with stirring at 400 rpm, and then from 227 ° C. to 270 ° C. at 0.6 ° C./min. The temperature was raised at a rate and maintained at 270 ° C. for 140 minutes. Then, the reaction system was gradually cooled to 250 ° C. while adding 2.346 kg (130.3 mol) of ion-exchanged water into the system over 15 minutes. The reaction system was then gradually cooled from 250 ° C. to 200 ° C. at a rate of 1.0 ° C./min and then rapidly cooled to near room temperature.

The obtained polymer was washed with 15 kg of N-methyl-2-pyrrolidone solvent (bath ratio 15) per 1 kg of dry PPS at 90 ° C. for 1.5 hours and filtered. The obtained cake was washed / filtered twice in ion-exchanged water (bath ratio 15) at 70 ° C. for 1.5 hours, and then ion-exchanged water containing 1% by weight of calcium acetate (bath ratio 15), 70. It was washed / filtered at ° C. for 1.5 hours, and then washed / filtered again with ion-exchanged water (bath ratio 15) at 70 ° C. for 1.5 hours. The obtained polymer was dried at a temperature of 150 ° C. under vacuum for 4 days to obtain a polyphenylene sulfide powder.

(Creation of particle pellets)
A slurry in which 50% by weight of calcium carbonate particles having an average particle size of 1.0 μm was dispersed in ethylene glycol was prepared. This slurry was filtered through a filter and then mixed with the polyphenylene sulfide powder polymer using a Henschel mixer so that the calcium carbonate content was 7.0% by weight. The resulting mixture was fed to a vent extruder with a 30 mm diameter biaxial screw and melted at a temperature of 320 ° C. This melt was passed through a filter made of metal fiber and having a hole diameter of 10 μm, and then extruded from a die having a hole diameter of 2 mm to obtain a gut-shaped resin composition. Further, the composition was cut to a length of about 3 mm to obtain particle pellets having a particle content of 5.0% by weight. Hereinafter, it is referred to as PPS resin A. (Creation of particle-free pellets)
Only the above polyphenylene sulfide powder polymer was melt-extruded in the same manner as the particle pellets to obtain particle-free pellets containing no particles. Hereinafter, it is referred to as PPS resin B.

(Comparative Example 1)
After mixing the PPS resin A and the PPS resin B obtained as described above so that the content of calcium carbonate is 1.0% by weight based on the total amount of the resin, 3 mmHg is used using a rotary vacuum dryer. It was dried at a temperature of 180 ° C. for 4 hours under reduced pressure. After drying, nitrogen having a purity of 99% by volume or more was introduced to equalize the pressure.

The dried pellets were supplied to a uniaxial extruder, melted at 310 ° C. in an atmosphere having an oxygen concentration of 0.1% by volume, and extruded into a sheet from a mouthpiece having a width of 940 mm and a lip gap of 3 mm over 130 minutes. Next, this sheet was wound around a casting drum having a surface temperature of 25 ° C. using an electrostatic application casting method and cooled and solidified to prepare an unstretched film.

Using the sequential biaxial stretching method, the obtained unstretched film was stretched 4.0 times in the longitudinal direction at a temperature of 100 ° C., passed through a tenter for further stretching in the width direction, and 3.5 in the width direction at a temperature of 100 ° C. It was double stretched. In the heat treatment chamber following the tenter used for further stretching in the width direction, the film was heat-treated at a temperature of 260 ° C., relaxed in the width direction under a limited shrinkage of 5%, and the film was wound around the core to 2000 mm in the width direction. An intermediate product roll of a polyphenylene sulfide film having a length of 6000 m was obtained.

(Comparative Example 2)
After drying the pellets under reduced pressure, low-purity nitrogen (nitrogen purity less than 99% by volume) was flowed in to equalize the pressure, and the film thickness, extrusion system A oxygen concentration, and residence time were compared except as shown in Table 1. An intermediate product roll of polyphenylene sulfide film was obtained in the same manner as in Example 1.

(Comparative Example 3)
After mixing PPS resin A and PPS resin B so that the content of calcium carbonate is 1.0% by weight in the particle pellets and the particle-free pellets, the temperature is 180 under a reduced pressure of 3 mmHg using a rotary vacuum dryer. It was dried at ° C. for 4 hours. After drying, low-purity nitrogen (nitrogen purity less than 99% by volume) was introduced to equalize the pressure.
The pellets dried as the A layer were supplied to the single-screw extruder A and melted at 310 ° C. Further, as the B layer, the PPS resin A and the PPS resin B before drying were supplied to another bent type twin-screw kneading extruder B and melted at 310 ° C. After passing each of these two polymers with high precision, they are laminated by a three-layer merging block provided with a rectangular laminated portion, and have a width of 940 mm, which is composed of an A layer / B layer / A layer with the A layer as the outermost layer. It was extruded into a sheet from a base having a lip gap of 3 mm. Next, this sheet was wound around a casting drum having a surface temperature of 25 ° C. using an electrostatic application casting method and cooled and solidified to prepare an unstretched film.
An intermediate product roll of the polyphenylene sulfide film was obtained by the above method and the same method as in Comparative Example 1 except as described in the table.

(Example 1)
An intermediate product roll of the polyphenylene sulfide film was obtained in the same manner as in Comparative Example 1 except that the residence time of the extrusion system A was shown in Table 1.

(Example 2)
An intermediate product roll of the polyphenylene sulfide film was obtained in the same manner as in Comparative Example 1 except that the thickness of the film and the residence time of the extrusion system A were shown in Table 1.

(Example 3)
Same as in Comparative Example 3 except that nitrogen having a purity of 99% by volume or more was flowed in after drying the pellets under reduced pressure to equalize the pressure, and the oxygen concentration of the extrusion system A and the residence time of the extrusion system B were shown in Table 1. An intermediate product roll of polyphenylene sulfide film was obtained by the above method.

(Summary of observation)
In Comparative Example 1, since the extrusion system residence time is long, the denaturation of polyphenylene sulfide progresses, and there are many defects in which the maximum fluorescence intensity wavelength exceeds 450 nm, and the film-forming stability and flatness are poor, and the low-quality polyphenylene sulfide film roll. was gotten. Further, since this roll has a thin thickness around the modified portion, it has a low withstand voltage resistance when used as a capacitor, and cannot be suitably used for a capacitor application.

In Example 1, a high-quality polyphenylene sulfide film roll was obtained in which the residence time of the extrusion system was short, so that the polyphenylene sulfide was not denatured and the defect that the maximum fluorescence intensity wavelength exceeded 450 nm was not observed.
In Example 2, a high-quality polyphenylene sulfide film roll was obtained in which the extruded oxygen concentration was low, so that the polyphenylene sulfide was not denatured and the defect that the maximum fluorescence intensity wavelength exceeded 450 nm was not observed.

In Comparative Example 2, since the extruded oxygen concentration was high, the polyphenylene sulfide was denatured, and a film having a large number of defects having a maximum fluorescence intensity wavelength exceeding 450 nm was obtained, resulting in poor flatness. Further, since this roll has a thin thickness around the modified portion, it has a low withstand voltage resistance when used as a capacitor, and cannot be suitably used for a capacitor application.

In Comparative Example 3, since the residence time in the extrusion system B is long, the denaturation of polyphenylene sulfide progresses, the number of defects in which the maximum fluorescence intensity wavelength exceeds 450 nm is large, and a low-quality polyphenylene sulfide film roll having poor flatness is obtained. Was done.

In Example 3, since the residence time in the extrusion system B was short, a high-quality polyphenylene sulfide film roll was obtained in which denaturation of polyphenylene sulfide did not occur and a defect that the maximum fluorescence intensity wavelength exceeded 450 nm was not observed.

Claims (12)

A polyphenylene sulfide film characterized in that the maximum wavelength of the fluorescence spectrum is not observed in the wavelength region of 450 nm or more in the film plane. The cross section of the film was measured 4096 by infrared spectroscopy (ATR method), a peak intensity at a range of a peak intensity (IR-p) and wavelength 1450～1500Cm ^-1 in the wavelength range of 1200~1250cm ^-1 (IR- A polyphenylene sulfide film in which the ratio of the ratio X being 0.01 or less is 0.5 or more when the ratio X [(IR-p) / (IR-s)] of s) is determined. The polyphenylene sulfide film according to claim 1 or 2, wherein the thickness of the film is 1.0 μm or more and 500 μm or less. A polyphenylene sulfide film roll obtained by winding a polyphenylene sulfide film, which is characterized in that a maximum wavelength of a fluorescence spectrum is not observed in a wavelength region of 450 nm or more in the film plane. The cross section of the film was measured 4096 by infrared spectroscopy (ATR method), a peak intensity at a range of a peak intensity (IR-p) and wavelength 1450～1500Cm ^-1 in the wavelength range of 1200~1250cm ^-1 (IR- When the ratio X [(IR-p) / (IR-s)] of s) is determined, the polyphenylene obtained by winding a polyphenylene sulfide film having a ratio X of 0.01 or less is 0.5 or more. Sulfide film roll. The polyphenylene sulfide film roll according to claim 4, wherein the thickness of the film is 1.0 μm or more and 500 μm or less. The polyphenylene sulfide film roll according to any one of claims 4 to 6, wherein the width of the film roll is 300 mm or more, and the length of the polyphenylene sulfide film wound on the roll is 500 m or more. .. The polyphenylene sulfide film roll according to any one of claims 4 to 7, wherein the orientation angle of the film is 85 degrees or less with respect to the longitudinal direction of the film. The polyphenylene sulfide resin composition is put into an extruder, melt-kneaded in the extruder, extruded from the mouthpiece to be cooled and solidified, and then stretched at least in the traveling direction of the film. The method for producing a polyphenylene sulfide film according to any one of claims 1 to 3, wherein the concentration is 1.0% by volume or less. The ninth aspect of the present invention is characterized in that the residence time of the resin from the addition of the polyphenylene sulfide resin composition to the extruder, the melt-kneading in the extruder, and the extrusion from the mouthpiece is less than 120 minutes. The method for producing a polyphenylene sulfide film according to the above method. The polyphenylene sulfide film resin composition is put into an extruder, melt-kneaded in the extruder, extruded from the mouthpiece to be cooled and solidified, and then stretched at least in the traveling direction of the film. The method for producing a polyphenylene sulfide film roll according to claim 4 to 8, which comprises a step of winding a polyphenylene sulfide film produced by a production method having an oxygen concentration of 1.0% by volume or less. The eleventh claim is characterized in that the residence time of the resin from the time the polyphenylene sulfide resin composition is put into the extruder to the time when the resin is melt-kneaded in the extruder and then extruded from the mouthpiece is less than 120 minutes. The method for producing a polyphenylene sulfide film roll according to the above method.