JP2020044839A - Thermoplastic resin film and electric/electronic component including the same, and insulation material - Google Patents

Abstract

To provide a thermoplastic resin film that is excellent in heat resistance, electric insulation and/or heat insulation and film-making stability as well as has reduced defects and excellent quality.SOLUTION: A thermoplastic resin film has a polyarylene sulfide resin as the main component, including a multilayer structure of two layers or more, where at least one layer of them is a layer (I) having holes, and a melting point of 275°C or lower.SELECTED DRAWING: None

Description

  The present invention relates to a thermoplastic resin film.

Films and nonwoven fabrics made of thermoplastic resins represented by polyarylene sulfide, polyetherimide, polyethylene naphthalate, polyamide, polyetheretherketone, liquid crystal polymer, fluororesin, etc. have heat resistance, electrical insulation, low moisture absorption, and high temperature. Because of its excellent dimensional stability and chemical resistance underneath, it is suitably used as an insulating material and a heat insulating material for electric / electronic parts, battery members, mechanical parts, and automobile parts.
In particular, a film made of polyarylene sulfide represented by polyphenylene sulfide (hereinafter, sometimes abbreviated as PPS) makes use of its heat resistance and flame retardant properties, and can be applied to filters and separators, and to insulators and heat insulation. Application studies on materials and substrates for circuit boards are underway (for example, Patent Documents 1 and 2). In these applications, a high level of electrical properties such as electrical insulation and low dielectric properties has recently been required, and techniques for making the film porous have been studied from the viewpoint of improving these properties. In order to make the film porous, a method of mixing a low melting point material (for example, Patent Document 3) or a method of finely stretching the sheet immediately after extruding the molten resin using a T-die by drafting to make the film porous may be used. However, there are problems such as the occurrence of stains on the mouthpiece due to the low melting point and the low retention stability and poor productivity.
In addition, a method has been proposed in which inorganic particles are added to a thermoplastic resin such as a polyarylene sulfide resin and biaxially stretched to form pores (Patent Document 5). In addition, there is a problem that the distance between the holes becomes short, the holes are connected, and a defect that can be visually observed occurs.

JP 2010-106408 A JP-A-10-259561 JP 2015-13913 A JP-A-58-67733 JP-A-2005-98577

  An object of the present invention is to solve the above problems. An object of the present invention is to provide a thermoplastic resin film which is excellent not only in heat resistance, electric insulation and / or heat insulation and film formation stability but also with few defects and excellent quality.

The thermoplastic resin film of the present invention has the following configuration in order to solve the above problems.
(1) A thermoplastic resin film containing a polyarylene sulfide resin as a main component, having a laminated structure of two or more layers, at least one of the constituent layers having pores, and a melting point of 275 ° C. or less. A thermoplastic resin film characterized by being the layer (I).
(2) a thermoplastic resin film according to (1), wherein the thermoplastic resin film to at least the diameter 50μm crater-like defect is 20 / m ² or less.
(3) The thermoplastic resin according to (1) or (2), wherein the orientation parameter of the layer (II) other than the layer (I) of the thermoplastic resin film is 0.8 to 1.4. the film.
(4) An electric / electronic component using the thermoplastic resin film according to any one of (1) to (3).
(5) An insulating material using the thermoplastic resin film according to any one of (1) to (3).
(6) The thermoplastic resin film according to (1), wherein the film is biaxially stretched.

Since the thermoplastic resin film of the present invention is excellent in heat resistance, electric insulation and / or heat insulation, it is used for electric / electronic devices, battery members, mechanical parts and automobile parts, insulating materials, heat insulating materials, tapes and circuit boards. It can be suitably used as a substrate, a film for a toner stirring bar for printing, and a film for release.

The thermoplastic resin film of the present invention comprises a resin containing a polyarylene sulfide resin as a main component.
Here, the main component means that the polyarylene sulfide resin accounts for 80% by mass or more of the raw material constituting the thermoplastic resin film.
The polyarylene sulfide resin used in the present invention is a homopolymer or a copolymer having a repeating unit of-(Ar-S)-. Examples of Ar include units represented by the following formulas (1) to (11).

(R1 and R2 are substituents selected from hydrogen, an alkyl group, an alkoxy group, and a halogen group, and R1 and R2 may be the same or different.)
The thermoplastic resin film of the present invention has a laminated structure of two or more layers. As the repeating unit of the polyarylene sulfide resin used in the layer (II) other than the layer (I) having a vacancy, a p-arylene sulfide unit represented by the above formula (1) is preferable. Examples thereof include polyphenylene sulfide, polyphenylene sulfide sulfone, and polyphenylene sulfide ketone. As a particularly preferable p-arylene sulfide unit, a p-phenylene sulfide unit is preferably exemplified from the viewpoint of film physical properties and economic efficiency.

  The thermoplastic resin film of the present invention has a structure including at least one or more layers (I) each having a hole and a layer (II) having a composition different from that of the layer (I).

  The polyarylene sulfide resin used in the thermoplastic resin film layer (II) of the present invention means that a p-arylene sulfide unit represented by the following structural formula is constituted by 97 mol% or more of all repeating units as a main structural unit. Is more preferable, and more preferably 98 mol% or more. If the content of such a main component is less than 97 mol%, the crystallinity, the glass transition temperature, and the like will be low, and the heat resistance, electric characteristics, and chemical resistance may be reduced.

  Further, as long as it is less than 3 mol% of the repeating unit, a unit containing a copolymerizable sulfide bond may be contained. Examples of such a repeating unit include a trifunctional unit, an ether unit, a sulfone unit, a ketone unit, a meta bonding unit, an aryl unit having a substituent such as an alkyl group, a biphenyl unit, a terphenylene unit, a vinylene unit, and a carbonate unit. Specific examples are given, and one or two or more of them can coexist. In this case, the structural unit may be in any form of random copolymerization or block copolymerization.

The molecular weight of the polyarylene sulfide resin used in the thermoplastic resin film layer (II) of the present invention is preferably 40,000 or more in weight average molecular weight, more preferably 40,000 to 80,000, more preferably 45,000 to 80,000. More preferably, it is from 000 to 75,000. When the molecular weight is in the above range, the entanglement of the molecular chains increases, so that stretchability and excellent mechanical properties are exhibited. The weight average molecular weight can be measured by gel permeation chromatography (GPC).
The thermoplastic resin film layer (II) of the present invention may or may not contain inorganic particles.

  When particles are contained in the thermoplastic resin film layer (II) of the present invention, the concentration of the particles is preferably 0.01 to 10% by mass relative to the layer (II), and 0.01 to 5% by mass. Is more preferred. With the above concentration, the function as a support of the layer (II) can be exhibited when the film is stretched. When the concentration of the particles contained in the layer (II) is more than 10% by mass, the film cannot withstand the stress applied to the film during stretching, so that the film is easily broken, and the film forming stability may be impaired.

  The melting point of the thermoplastic resin film layer (I) of the present invention is 275 ° C. or less. By setting the melting point of the thermoplastic resin film layer (I) within the above range, when forming the pores under the stretching conditions described later, a part of the pores is melted or softened, the stretching stress is absorbed, and the connection of the pores is prevented. For this reason, it is possible to suppress an increase in defects and breakage of the film during film formation while maintaining a high porosity. If the melting point is higher than 275 ° C., the number of defects may increase or the stability of film formation may decrease. Further, the lower limit of the melting point is preferably 230 ° C. or more from the viewpoints of heat resistance reduction and film formation stability. The melting point of the thermoplastic resin film layer (I) can be controlled by polymerizing the polyarylene sulfide resin with the above-described composition. The melting point of the thermoplastic resin film layer (I) is more preferably from 245 ° C to 275 ° C, even more preferably from 245 ° C to 260 ° C. The melting point of the thermoplastic resin film layer (I) can be measured using a method described later.

  As a method for keeping the melting point of the thermoplastic resin film layer (I) of the present invention in the above range, it is preferable to use a copolymerized polyarylene sulfide resin for the layer (I), and preferably 80 to 95 mol% or less is a poly-arylene sulfide resin. By being composed of a p-arylene sulfide unit, more preferably 85 to 92 mol%, it is possible to obtain a polyarylene sulfide resin having a melting point in the above range. If the content of such a component is less than 80 mol%, the crystallinity may decrease, and the heat resistance and the film formation stability may decrease. If the content exceeds 95 mol%, the polyarylene sulfide resin used for the thermoplastic resin film layer (I) may be used. May not be able to sufficiently lower the melting point, thereby increasing the number of defects.

  Preferred copolymer units are

(Here, X represents an alkylene, CO, or SO ₂ unit.)

(Where R represents an alkyl, nitro, phenylene, or alkoxy group), and a particularly preferred copolymer unit is an m-phenylene sulfide unit. The mode of copolymerization with the copolymer component is not particularly limited, but is preferably a random copolymer.

  The porosity of the thermoplastic resin film layer (I) of the present invention is 20% or more, preferably 20 to 70%, more preferably 35 to 60%, and still more preferably 45 to 60%. Here, the porosity refers to the ratio of the area of the vacancies contained in the image of an arbitrary size of the layer (I) when the area of the image is 100, and the arbitrary size of the layer (I) In the case where no vacancy is observed in the cross-sectional image, the porosity is 0%. If the porosity is smaller than 20%, the number of porosity contained in the thermoplastic resin film is reduced, and the proportion of air having a small dielectric constant in the film is reduced, so that electric characteristics may be reduced. The porosity is preferably as high as possible, but is preferably 70% or less from the viewpoint of maintaining productivity. The porosity within the above range can be achieved by applying the particle concentration and film forming conditions described later. The porosity can be confirmed by evaluating the cross section of the laminate by a method described later.

  As a method of forming pores in the thermoplastic resin film layer (I) of the present invention, a dry method (a method in which a resin is melted and extruded into a sheet shape, and a porous material is stretched to form a porous film) is used because the process is simplified and the productivity is excellent. Is preferable. In addition, in consideration of the retention stability and productivity in the dry method, a method of forming the pores around the particles by adding and stretching the inorganic particles to the layer for forming the pores is preferably used. .

  The concentration of the particles contained in the thermoplastic resin film layer (I) of the present invention is based on 100% by mass of the raw material composition of the resin resin layer constituting the thermoplastic resin film layer (I) and other additives. The content is preferably 10% by mass or more, more preferably 10 to 60% by mass, and particularly preferably 15 to 40% by mass. By setting the particle concentration within the above range, pores can be efficiently formed. When the particle concentration is less than 10% by mass, pores may be difficult to be formed because the particle concentration is low at the time of film production described below. On the other hand, when the particle concentration exceeds 60% by mass, stretching becomes difficult during the production of the thermoplastic resin film, and the productivity may be reduced.

  Particles preferably used in the thermoplastic resin film layer (I) of the present invention include oxide ceramics such as alumina, silica, titania, zirconia, magnesia, ceria, yttria, zinc oxide, iron oxide, silicon nitride, titanium nitride, and the like. Nitride ceramics such as boron nitride, silicon carbide, calcium carbonate, aluminum sulfate, barium sulfate, potassium titanate, talc, kaolin clay, kaolinite, halloysite, pyrophyllite, montmorillonite, sericite, mica, amesite, bentonite And inorganic compounds such as asbestos, zeolite, calcium silicate, magnesium silicate, diatomaceous earth, silica sand and other ceramics, glass fibers and the like. One type of particles may be used, or a plurality of types may be mixed and used. Among these, calcium carbonate, barium sulfate, zinc oxide and silica are preferred from the viewpoint of dispersibility and defect suppression, and calcium carbonate, barium sulfate and silica are most preferred from the viewpoint of defect suppression.

  The particles used in the thermoplastic resin film layer (I) of the present invention can be subjected to a surface treatment as long as the physical properties of the thermoplastic resin film are not impaired.

  The volume average particle diameter of the particles used in the thermoplastic resin film layer (I) of the present invention is preferably from 1 to 20 μm, more preferably from 3 to 20 μm, even more preferably from 5 to 10 μm. By using particles having the above volume average particle size, aggregation of particles that are likely to occur when the particles are blended at a high concentration is suppressed, and stress is concentrated around the particles when stretched. Voids can be efficiently formed in I). When the volume average particle diameter of the particles is less than 3 μm, it is difficult to form pores during stretching, the porosity is reduced due to the reduced size of the pores, and the aggregation is caused due to the increased surface area of the particles. There are cases. If the volume average particle size is larger than 20 μm, the film may easily break during stretching due to penetration of the particles, and the productivity of the thermoplastic resin film may be reduced. The volume average particle diameter and concentration of the particles used for the thermoplastic resin film layer (I) of the present invention can be confirmed by using a method described later.

  The particles preferably used for the layer (I) constituting the thermoplastic resin film of the present invention are a laser diffraction method (a method for determining the particle size by analyzing the intensity distribution of diffracted light obtained by irradiating the particles with a laser beam). ), The particle diameter (D50: median diameter) of a 50% numerical value corresponding to the median of the particle size distribution (cumulative distribution) obtained is preferably 1 to 10 μm, more preferably 3 to 20 m, and More preferably, it is 10 μm. By using the particles of D50 described above, it is possible to suppress the aggregation of particles that are likely to occur when the particles are blended at a high concentration, and to concentrate stress around the particles when stretched. Holes can be formed efficiently. If the D50 of the particles is less than 1 μm, aggregation may easily occur due to an increase in the surface area of the particles, and productivity may decrease, or porosity may decrease due to difficulty in forming pores during stretching. On the other hand, when D50 is larger than 10 μm, film breakage is likely to occur during stretching due to penetration of particles, and the productivity of the thermoplastic resin film may be reduced.

  The particles used in the layer (I) constituting the thermoplastic resin film of the present invention preferably have a particle diameter (D90) of 90% of the cumulative distribution obtained by the particle size distribution measurement of 20 μm or less, and 16 μm or less. Is more preferable. When D90 satisfies the above range, the width of the particle size distribution can be narrowed, and the stress distribution during stretching can be made uniform, so that the generation of minute voids can be suppressed. When D90 is larger than 20 μm, the content of large-diameter particles, which tend to concentrate stress during stretching, increases, so that non-uniform stretching occurs, and fine pores are formed near small-diameter particles, which are difficult to transmit stretching stress. May increase and the mechanical properties may decrease. The lower limit of D90 is preferably as close to D50 from the viewpoint of making the particle diameter uniform.

  The particles used in the layer (I) constituting the thermoplastic resin film of the present invention preferably have a D90 / D50 ratio (D90 / D50) of 4.0 or less obtained by particle size distribution measurement, and D3.0. It is more preferably at most 2.5, more preferably at most 2.5. By setting D90 / D50 within the above range, the width of the particle size distribution can be narrowed, and the stress distribution during stretching can be made uniform, so that the generation of minute pores can be suppressed. In addition, since the diameter of the pores formed can be controlled more uniformly by making the particle diameter close to D50, variation in electrical characteristics can be suppressed. When D90 / D50 is larger than 4.0, stress at the time of stretching is concentrated around the included particles of D90 or more, and it becomes difficult to uniformly transmit the stress to the particles on the smaller diameter side than D50. May increase, or coarse pores may be formed in the vicinity of large-diameter particles forming D90, and the electric characteristics may vary. The lower limit of D90 / D50 is preferably as close to 1 as possible from the viewpoint of making the particle diameter uniform. The particle size distribution of the particles contained in the thermoplastic resin film can be confirmed by a method described later.

  The particle diameter and particle concentration of the cumulative distribution of 50 and 90% obtained by the particle size distribution measurement of the particles preferably used for the layer (I) constituting the thermoplastic resin film of the present invention should be confirmed by the method described later. Can be. The polyarylene sulfide resin used for the thermoplastic resin film layer (II) of the present invention and / or the polyarylene sulfide resin composition used for the layer (I) may include an antioxidant, a heat-resistant agent, and the like as long as the effects of the present invention are not impaired. Various additives such as a stabilizer, an antistatic agent and an antiblocking agent may be contained.

  The thermoplastic resin film of the present invention may be any of an unstretched film, a uniaxially oriented film (a film stretched in any one direction), and a biaxially stretched film (a film stretched biaxially in any direction and a direction perpendicular thereto). However, from the viewpoint of characteristics and productivity, a biaxially oriented film is preferable. As a method for obtaining a biaxially oriented film, a sequential biaxial stretching method (a stretching method in which stretching in one direction is combined such as a method of stretching in the longitudinal direction and then stretching in the width direction), a simultaneous biaxial stretching method (long (A method of simultaneously stretching in the width direction and the width direction) or a method of combining them. Among them, the sequential biaxial stretching method is particularly preferable from the viewpoint of productivity. The presence or absence of stretching and the axial direction can be confirmed by measuring the shrinkage at 250 ° C. of the film by a method described later.

  The thermoplastic resin film of the present invention has a laminated structure of two or more layers. By having two or more layers, the stretchability of the thermoplastic resin film itself is improved, tearing is suppressed, and productivity can be improved. As a laminated structure, two layers (I) / (II) composed of a layer (I) and a layer (II), (I) / (II) / (I), (II) / (I) / ( (II), (II) / (I) / (II) / (I), (II) / (I) / (II) / (I) / (II) Not done.

  The thickness of the thermoplastic resin film of the present invention is not particularly limited, but is preferably 1 to 300 μm, more preferably 5 to 300 μm, and still more preferably 10 to 250 μm from the viewpoint of film forming properties.

The thickness of the thermoplastic resin film can be controlled by adjusting the supply amount of the raw material, the take-up speed, and the stretching ratio when obtaining an unstretched sheet. The film thickness can be evaluated by a method described later.
The thermoplastic resin film of the present invention has a laminated structure composed of a layer (I) and a layer (II), and the layer (I) represented by the formula (a) has a laminated ratio of 0.40 to 0.95. Preferably, there is.

(A) Lamination ratio of layer (I) = layer (I) thickness / (layer (I) + layer (II) thickness)
By setting the lamination ratio in the above range, both electrical characteristics such as dielectric constant and weight reduction can be achieved. When the lamination ratio of the layer (I) is less than 0.40, it is difficult to reduce the weight, which may lead to an increase in cost. On the other hand, when the ratio of the thickness of the layer (I) exceeds 0.95, electric characteristics such as a dielectric constant may be poor. The ratio of the thickness of the layer (I) is more preferably 0.60 or more and 0.90 or less, and further preferably 0.70 or more and 0.85 or less. The lamination ratio of the layer (I) of the thermoplastic resin film within the above range can be achieved by adjusting the discharge amount during melt extrusion. The lamination ratio of the layer (I) of the thermoplastic resin film of the present invention can be measured using a method described later.

The thermoplastic resin film of the present invention, from the viewpoint of electrical characteristic improvement such as vapor deposition plaque inhibition and the dielectric constant at the time of deposition, it is preferable that disadvantages of more in diameter 50μm crater-like is 20 / m ² or less, more preferably Is 10 / m ² or less. When a crater-like defect occurs, when the thermoplastic resin film of the present invention is used for an electrical insulating material or a heat insulating material, when a deposition unevenness occurs during processing such as vapor deposition, or when a defect such as bending is formed, a through hole is formed in the defect portion. This is not preferable because electrical characteristics such as dielectric constant may occur.

Further, when the number of crater-like defects exceeds 20 / m ² , not only the deposition unevenness and the electrical characteristics are inferior, but also the film breaks during running of the film during processing and through holes may be generated in the defect portions.

Here, the crater-shaped defect refers to a substantially circular concave shape, which has a concave shape when the defect surface is observed by the Vert SCan method, and the defect is photographed with a microscope. Using image analysis software (MacView ver. 4.0, manufactured by Mountech Co., Ltd.) from the photograph, the area and perimeter were derived, and the circularity calculated by the following equation (a) was in the range of 0.8 to 1.0. It refers to those having a diameter of 50 μm or more. As for the degree of circularity, 1.0 is the maximum value and 1.0 is a perfect circle.
Equation (b) circularity = 4 ＝ × (area) ÷ (perimeter) ²
As a method for keeping the crater-like defects of the thermoplastic resin film in the above range, the layer (I) may be produced by using the above-mentioned copolymerized polyarylene sulfide resin having a melting point of 275 ° C. or less and by the production method described below. Can be more preferably achieved.

  The orientation parameter of the thermoplastic resin film layer (II) of the present invention is preferably from 0.8 to 1.4, and more preferably from 0.9 to 1.2. When the orientation parameter falls within the above range, mechanical properties are improved, and heat resistance and workability can be improved. When the orientation parameter is 0.8 or less, heat resistance and workability may be poor. On the other hand, if the ratio is larger than 1.4, the film may be easily torn, and the film may be broken during processing. Making the orientation parameter fall within the above range can be achieved by manufacturing by a manufacturing method described later. The orientation parameter can be confirmed by a method described later.

  The dielectric constant of the thermoplastic resin film of the present invention at a frequency of 10 GHz at a temperature of 23 ° C. and 65% RH is preferably 3.0 or less, more preferably 2.5 or less. By having the above characteristics, when used as a circuit board material in a high frequency region, the parasitic capacity of the insulating material can be reduced, so that transmission loss can be effectively suppressed. When the dielectric constant is higher than 3.0, transmission loss may increase when used as a substrate material. The lower the dielectric constant, the better, but the feasible range is 1.8 or more. The dielectric constant within the above range can be achieved by forming a film by a manufacturing method described later. The dielectric constant can be evaluated by a method described later.

  The thermoplastic resin film of the present invention preferably has an average strength retention of 50 to 100% in the length direction after treatment at 200 ° C./1000 hours and in the direction perpendicular to the length direction in the film plane, and 60%. It is more preferably from 100 to 100%, more preferably from 80 to 100%. Here, the length direction is defined as 0 ° in any direction of the thermoplastic resin film, and when measured while changing the direction in the film plane from −90 ° to 90 ° in steps of 10 °, the breaking strength is the highest. It is the direction in which it has become smaller. By setting the strength retention in the above range, the mechanical properties and electrical properties of the thermoplastic resin film when used at high temperatures for a long time can be maintained. If the strength retention is less than 50%, the long-term heat resistance is inferior, and when used for a long time at a high temperature, cracks may occur due to deterioration and electrical characteristics may be deteriorated. In order to maintain the strength retention in the above range, it can be achieved by using a resin having the above-mentioned melting point and stretching by a method described later. The strength retention can be evaluated by a method described later.

  In the method for producing the film of the present invention, a thermoplastic resin film using a poly-p-phenylene sulfide resin (hereinafter sometimes abbreviated as a PPS resin) as a polyarylene sulfide resin in the thermoplastic resin film layer (II). Method for producing film in the case of using poly-m-phenylene sulfide resin obtained by copolymerizing m-phenylene sulfide with PPS as polyarylene sulfide resin in layer (I) (hereinafter sometimes abbreviated as copolymerized PPS resin) Will be described as an example, but the present invention is not limited to this example.

  Examples of the method for producing the PPS resin include the following method. Sodium sulfide and p-dichlorobenzene are reacted in an amide-based 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, alkali metal carboxylate and the like are added as a polymerization degree regulator, and the polymerization reaction is performed at a temperature of 230 to 280 ° C. After the polymerization, the polymer is cooled, and the polymer is converted into a water slurry and filtered through a filter to obtain a granular polymer. This is stirred in an aqueous solution of acetate or the like at a temperature of 30 to 100 ° C. for 10 to 60 minutes, washed several times with ion-exchanged water at a temperature of 30 to 80 ° C., and dried to obtain a PPS granular polymer. After washing this with high-temperature water of 30 to 100 ° C., it is washed twice or more, more preferably three or more times with an aqueous solution of acetic acid or an aqueous solution of acetate (eg, sodium acetate or calcium acetate). After washing with ion-exchanged water and drying, a granular polymer of PPS is obtained.

As a method for producing the copolymerized PPS resin, for example, there is the following method. Sodium sulfide and p-dichlorobenzene and m-dichlorobenzene are blended in the ratio according to the present invention, and in an amide polar solvent such as N-methyl-2-pyrrolidone (NMP) in the presence of a polymerization aid under high temperature and high pressure. To react. If necessary, a copolymer component such as trihalobenzene can be included. Caustic potash or alkali metal carboxylate is added as a polymerization degree regulator, and the polymerization reaction is performed at a temperature of 200 to 280 ° C. After the polymerization, the polymer is cooled, and the polymer is converted into a water slurry and filtered through a filter to obtain a granular polymer. After washing this with high-temperature water of 30 to 100 ° C., it is washed twice or more, more preferably three or more times with an aqueous solution of acetic acid or an aqueous solution of acetate (eg, sodium acetate or calcium acetate). After washing with ion-exchanged water and drying, a granular polymer of copolymerized PPS is obtained.
PPS obtained as a polyarylene sulfide resin and a copolymerized polyarylene sulfide resin, the copolymerized PPS polymer, are introduced into a vented extruder, melt-extruded into strands, cooled with water at a temperature of 25 ° C., and then cut. To produce a chip.

  As for the thermoplastic resin film, the PPS resin chip and the copolymerized PPS resin chip are supplied to separate melt extruders and heated to the melting point of each resin or higher. Each raw material melted by heating is laminated in a molten state into three layers of PPS layer / copolymerized PPS layer / PPS layer in a joining device provided between the melt extruder and the outlet of the die. Extruded. The sheet is closely adhered to a cooling drum having a surface temperature of 20 to 70 ° C. to be cooled and solidified, thereby forming a substantially non-oriented three-layer laminated sheet of layer (II) / layer (I) / layer (II). obtain.

  Next, biaxial stretching is performed. The unstretched film obtained above is subjected to a sequential biaxial stretching machine or a simultaneous biaxial stretching machine in a range from the glass transition point of the copolymerized PPS resin used for the layer (II) to the cold crystallization temperature. After biaxial stretching with a biaxial stretching machine, heat treatment is performed to obtain a biaxially oriented film. As a stretching method, a sequential biaxial stretching method (a stretching method in which stretching in one direction is combined such as a method of stretching in the width direction after stretching in the longitudinal direction), a simultaneous biaxial stretching method (stretching in the longitudinal direction and the width direction). Simultaneous stretching) or a combination thereof can be used, but the sequential biaxial stretching method is most preferably employed from the viewpoint of suppressing defects.

In the sequential biaxial stretching method, as the first stretching method in the longitudinal direction, the unstretched film is stretched 3.0 to 5.0 times, more preferably 3.5 to 4.5 times in the longitudinal direction using a heating roll. Stretching is performed, and it is preferable to perform stretching in two stages (multi-stage stretching in the longitudinal direction) from the viewpoint of suppressing defects, and the relationship between the stretching temperature and the stretching ratio of the first and second stages is expressed by the following formulas (c, d) simultaneously. Preferably, it is satisfied. Here, the stretching temperature is the glass transition temperature (Tg _A ) to (Tg _A +20) ° C. of the PPS used for the layer (II), and preferably (Tg _A ) to (Tg _A +15) ° C.
Formula (c) T1 <T2 2 ° C ≦ T2-T1 ≦ 20 ° C 90 ° C <T1 <108 ° C
92 ° C <T2 <110 ° C
Formula (d) R1 <R2 1.2 ≦ R1 ≦ 2.0 1.5 ≦ R2 ≦ 3.3
3.0 ≦ R1 + R2 ≦ 5.0
Here, the first-stage stretching temperature (T1), the second-stage stretching temperature (T2), the first-stage stretching ratio (R1), and the second-stage stretching ratio (R2) are shown.

Longitudinal stretching temperature in the present invention, after preheating in the range of {layers glass transition temperature of the PPS used in _{(II) (Tg A) -10} ℃)} ~Tg A, Tg A ~ (Tg A +20) ℃, Preferably, it is guided to a stretching roll heated to a range of (Tg _A ) to (Tg _A +15) ° C. and stretched in the longitudinal direction (MD direction). At this time, the preheating temperature is preferably equal to or lower than the stretching temperature, and more preferably lower than the MD stretching temperature by 2 ° C. or more. By setting the above preheating temperature, excessive heating can be prevented during preheating, and the stretching stress can be uniformly propagated during the subsequent longitudinal stretching, so that the orientation uniformity during the longitudinal stretching is reduced. When the biaxially stretched film is formed in the subsequent step, the planarity can be improved. Thereafter, cooling is performed with a cooling roll group at 20 to 50 ° C.

As a stretching method in the width direction (TD direction) following the MD stretching, for example, a method using a tenter is generally used. Both ends of the film are gripped with clips, guided to a tenter, and stretched in the width direction (TD stretching). The stretching temperature is preferably from Tg _A to (Tg _A +15) ° C., more preferably from (Tg _A ) to (Tg _A +10) ° C., from the viewpoint of sufficiently orienting the film at the time of stretching and improving film forming stability and flatness. It is preferable to stretch 3.5 to 5.0 times, preferably 3.5 to 4.5 times.

Next, an operation (heat setting treatment) of heat setting the stretched film under tension is performed. Temperature of heat-setting is the melting point _(Tm A) -10 ℃ _~PPS melting point _(Tm A) -30 ℃ of PPS used in the thermoplastic resin film layer (II), preferably _Tm A -10 ° C. to Tm _A- 20 ° C. By setting the heat setting temperature within the above range, thermal stability such as dimensional stability during processing can be improved.

[Method of measuring characteristics]
(1) When measuring the film thickness, the lamination ratio, and the overall thickness of the layered thermoplastic resin film, use a dial gauge to measure the thickness of any five locations of the sample cut out of the film, and calculate the average value. I asked.
When measuring the layer thickness of each layer of the thermoplastic resin film, the cross section of the film is cut out with a microtome in a direction parallel to a direction perpendicular to the length direction in the film plane. The cross section of the film was photographed using a Leica DMLM manufactured by Leica Microsystems Co., Ltd. with a photograph of transmitted light at a magnification of 100 times, and the thickness of each layer of the thermoplastic resin film was determined arbitrarily for each layer. Five places were measured, and the average value was taken as the layer thickness of each layer.
Here, the length direction and the direction perpendicular to the length direction in the film plane refer to the direction obtained by the measurement method (9).

(2) Glass transition point and melting point of thermoplastic resin constituting layers (I) and (II) A DSC (RDC220) manufactured by Seiko Instruments Inc. as a differential scanning calorimeter according to JIS K7121-1987, and a data analyzer manufactured by the company as a differential scanning calorimeter A disk station (SSC / 5200) is used. From the thermoplastic resin film, the layer (I) and the layer (II) were cut out using a microplane to obtain 5 mg, taking into account the thickness of each layer measured in (1), and separately collected to obtain samples for each layer. The temperature is raised to 350 ° C. at a rate of 20 ° C./min (1st Run). Next, the sample is taken out, rapidly cooled, and then heated from room temperature to 350 ° C. at a rate of 20 ° C./min (2nd Run). The glass transition point and the peak temperature of the endothermic peak of melting confirmed in the 2nd Run DSC chart were defined as the glass transition point (Tg) and melting point (Tm) of the thermoplastic resin constituting each layer.

(3) Orientation parameter Using a micro ATR (Frontier Spotlight 400 manufactured by Perkin Elemer Co., Ltd.), the spectrum is measured in a direction perpendicular to and parallel to the film length direction of the thermoplastic resin film layer (II). The resulting vertical, with the absorbance of absorbance and 1390 cm ^-1 in the direction parallel 1093Cm ^-1, was determined orientation parameters by the following equation.
Here, the length direction and the direction perpendicular to the length direction in the film plane refer to the direction obtained by the measurement method (9).
Orientation parameter = (I ₁₀₉₃ (parallel) / I ₁₃₉₀ (parallel)) / (I ₁₀₉₃ (vertical) / I ₁₃₉₀ (vertical))
Number of integration: 10 times.

(4) Porosity (%)
Using a sputtering apparatus, the sample fixed on the sample stage of the scanning electron microscope was observed under a condition of 10 ⁻³ Torr, a voltage of 0.25 KV, and a current of 12.5 mA using a sputtering apparatus so that a cross section with the thickness direction as a normal direction could be seen. After performing ion etching treatment for 10 minutes to cut the cross section, the surface was subjected to gold sputtering with the same apparatus, and observed at a magnification of 2000 using a scanning electron microscope. Using the image analysis software (MacView ver. 4.0, manufactured by Mountech Co., Ltd.), the obtained observation image is binarized so that the resin portion is white and the holes are black, and the image is positioned at a position in the thickness direction of the observation image. On the other hand, the intensity is taken and the distribution is graphed. The point at which the intensity of the density turned to increase in the density distribution was determined as an interface, and the layer (I) having pores and the other layer (II) were distinguished. Using the image analyzer, the area A (μm ² ) of the hole portion and the total area B (μm ² ) of the layer in the observation image were calculated for the layer (I) having the holes in the observation image. The porosity C (%) of the layer (I) was determined by applying the following formula. The evaluation was carried out at five points in each of two directions, that is, an arbitrary direction of the film and a direction perpendicular thereto, taking a total of 10 observation images and calculating the porosity, and averaging the 10 points to the layer (I) Porosity (%).
Porosity C (%) of layer X = area A (μm ² ) of porosity portion in layer / total area B (μm ² ) × 100 of layer.
(5) Particle concentration / volume average particle diameter a. After confirming the thickness of the thermoplastic resin film and each layer using the method of particle concentration (1), the surface layer of the thermoplastic resin film is scraped off using a microplane within a range not exceeding the thickness of the surface layer. The shaved sample is placed in a weighed crucible and weighed again, and the weight of the sample before heating is weighed. Next, the crucible containing the sample is heated at 500 ° C./6 h in a muffle furnace (manufactured by Yamato Scientific Co., Ltd.) to incinerate the sample. After the crucible was cooled, it was weighed, the weight after heating was measured, and the weight before and after heating was inserted into the following formula to calculate the content (particle concentration) of the inorganic particles contained in the film. The sample amount was adjusted so that the mass of the residue was in the range of 100 to 200 mg.
Particle concentration (% by mass) = weight after heating (mg) / weight before heating (mg) × 100.
b. Volume average particle size a. Using a dispersion obtained by mixing the residue obtained in the above with purified water, using a laser diffraction / scattering particle size distribution analyzer (Microtrack MT3000, manufactured by Nikkiso Co., Ltd.) under the conditions of a laser beam wavelength of 780 nm and a measurement temperature of 25 ° C. Before the measurement, ultrasonic treatment was performed for 4 minutes, followed by measurement according to JIS Z8825-1: 2001, and the particle size distribution of the sample was determined. The dispersion was adjusted so that the transmittance of the measurement light source was about 90%. From the obtained particle size distribution, the volume average particle size was calculated using the following equation.
Volume average particle size (μm) = Σ (vd) / Σv
d: representative value of each particle size channel, v: percentage of particle content (vol%) for each particle size channel.

(6) Dielectric constant The dielectric constant is measured by a cavity resonator perturbation method at a frequency of 10 GHz using a dielectric material measuring device (manufactured by Kanto Electronics Application Development Co., Ltd.). A sample cut in a direction of 2.7 mm perpendicular to the length direction in the film plane and 45 mm in the film length direction was inserted into the cavity resonator, and the measurement was performed in a 23 ° C. and 65% RH environment. The measurement was performed at n = 3, and the average value was obtained and evaluated according to the following criteria.
Here, the length direction and the direction perpendicular to the length direction in the film plane refer to the direction obtained by the measurement method (9).
A: Dielectric constant is 2.5 or more B: Dielectric constant is more than 2.5 and 3.0 or less C: Dielectric constant is more than 3.0.

(7) Number of Crater-like Defects An arbitrary portion of the thermoplastic resin film was photographed with an area of 1 m ² using VertScan 2.0 (R5300GL-Lite-AC, manufactured by Ryoka Systems Inc.) under the following conditions.
Measurement conditions: OCD camera SONY HR-57 1/2 inch
Objective lens 5x
Intermediate lens 0.5x
Wavelength filter 530nm white
Measurement mode Focus
Next, using the attached analysis software (MacView ver. 4.0, manufactured by Mountech Co., Ltd.), the photographed screen is surface-corrected by a polynomial fourth-order approximation, and a defect having a concave shape is extracted. Microscopic images were taken. Using the image analysis software, the area and perimeter of the defect portion were derived from the obtained image of the defect portion, and the circularity was determined by the following equation.
Circularity = 4 x (area) / (perimeter) ²
The measurement was performed, and defects having a circularity in the range of 0.8 to 1.0 and a diameter of 50 μm or more were counted as crater-like defects.

(8) A test piece cut to a width of 10 mm and a length of 250 mm while changing any direction of the heat-resistant thermoplastic resin film to 0 ° and changing the direction from −90 ° to 90 ° in steps of 10 ° in the film plane. According to the method specified in JIS-C2151, a 10 mm wide sample piece was set to have a chuck-to-chuck length of 100 mm using a Tensilon tensile tester, and a tensile test was performed at a tensile speed of 300 mm / min. Here, when the breaking strength was measured while changing the direction, the direction in which the breaking strength became the smallest was determined as the length direction of the film.
Next, in a length direction and a direction perpendicular to the length direction in the film plane, a test piece cut to a width of 10 mm and a length of 250 mm was subjected to heat treatment in a hot air oven set at a temperature of 200 ° C. for 1000 hours. Then, the breaking strength before and after the heat treatment was measured. Based on the obtained value, the strength retention was calculated from the following equation, and evaluated according to the following criteria.
The measurement was performed 10 times each in the length direction and in the direction perpendicular to the length direction in the film plane, and the average value was obtained and evaluated according to the following criteria.

Strength retention (%) = Y / Y0 × 100
Y0: breaking strength before heat treatment (MPa)
Y: breaking strength after heat treatment (MPa)
AA: 80% or more A: Strength retention of 60% or more and less than 80% B: Strength retention of 50% or more, less than 60% C: Strength retention of less than 50%.

(9) Processability A thermoplastic resin film is sampled from an arbitrary position to a size of 10 cm × 10 cm, and the degree of vacuum is 1.0 Torr or less, using a vacuum evaporation device (VPC-260F) manufactured by ULVAC KIKO CO., LTD. After depositing aluminum having a thickness of 25 to 30 nm and a thickness of 50 nm, the sample is placed in parallel on a flat metal plate so that the deposition surface is facing upward, and after standing for 10 seconds, the surface state of the sample is visually observed and the following criteria are applied. Was evaluated. In addition, those having no visible irregularities were observed with an optical microscope (manufactured by Leica, DM2500, magnification 10 times) to confirm the presence or absence of irregularities.
AA: No irregularities can be confirmed visually or with an optical microscope.
AA: No irregularities can be visually confirmed, but less than 5 irregularities can be formed with an optical microscope.
B: No irregularities can be visually observed, but six or more irregularities can be formed with an optical microscope.
C: There are irregularities that can be visually confirmed.

(10) Transmission loss
After applying a circuit board adhesive AW-32 (manufactured by Kyodo Yakuhin Co., Ltd.) to both surfaces of the thermoplastic resin film at a solidified thickness of 2 μm, a 12 μm copper foil (3EC-HTE, manufactured by Mitsui Kinzoku Kogyo Co., Ltd.) Was laminated on both surfaces by pressing at a pressure of 4 MPa for 10 minutes using a vacuum heat press apparatus heated to 170 ° C. to produce a laminate having a configuration of copper foil / thermoplastic resin film / copper foil. A microstrip line having a wiring width of 140 μm and a length of 100 mm was formed as a circuit pattern on the copper foil surface of the obtained laminate by a chemical etching method, and used as a sample for evaluation. Immediately after the above sample was left for 24 hours in an environment of a temperature of 23 ° C. and a humidity of 65% RH, a 10-40 GHz frequency was measured using a network analyzer (“8722ES” manufactured by Agilent Technology) and a cascade microtech probe (ACP40-250). The transmission loss (dB / 100 mm) was measured, and the absolute value (dB / 100 mm) was evaluated according to the following criteria.
A: Absolute value of transmission loss is less than 15 dB / 100 mm B: Absolute value of transmission loss is 15 dB / 100 mm or more and less than 25 dB / 100 mm C: Absolute value of transmission loss is 25 dB / 100 mm or more
(11) Quality (variation in electrical characteristics)
A test piece of a square having a side of 50 mm is cut out from an arbitrary part of the thermoplastic resin film, and is sampled with an electronic micrometer (K-312A type, a needle pressure of 30 g, manufactured by Anritsu Corporation) in an atmosphere of 23 ° C. and 65% RH. Were measured at any three locations, and the average value was taken as the sample thickness (μm). Next, the partial discharge starting voltage is measured using a partial discharge measuring device (model name “QM-50” manufactured by Mitsubishi Cable Industries, Ltd.). The test piece is sandwiched between a stainless steel plate and a brass electrode. An AC voltage was applied to the stainless steel plate and the brass electrode at a step-up rate of 200 Vrms / sec, and the voltage value when the amount of discharge charge measured by the partial discharge measuring device reached 100 pC was measured. This is inserted into the following equation, and the partial discharge starting voltage of the sample in terms of 200 μm is obtained.
Partial discharge starting voltage (V) in terms of 200 μm = measured value (V) / thickness (μm) × 200 (μm)
The measurement was carried out at n = 50, and the width (range) of the numerical value was determined from the maximum / minimum value of the obtained measured values, and evaluated according to the following criteria.
AA: The range is less than 100 V A: The range is 100 V or more and less than 500 V B: The range is 500 V or more (12) Thermoplastic resin using the method of particle diameter (1) of 50, 90% of the cumulative distribution of layer (I) After confirming the thickness of each layer of the film, a desired layer in the thermoplastic resin film is cut off using a microplane within a range not exceeding the thickness. After placing the shaved sample in a weighed crucible, the sample is heated at 500 ° C./6 h in a muffle furnace (manufactured by Yamato Scientific Co., Ltd.) to incinerate the sample. After cooling the crucible, the obtained residue was mixed with purified water and adjusted so that the transmittance was about 90%. This dispersion was subjected to ultrasonic treatment for 4 minutes before measurement using a laser light diffraction scattering particle size distribution analyzer (Microtrack MT3000, manufactured by Nikkiso Co., Ltd.) at a laser light wavelength of 780 nm and a measurement temperature of 25 ° C. Measurement was performed according to JIS Z8825-1: 2001, and the particle diameters (D50, D90) of 50% and 90% of the cumulative distribution were determined from the particle size distribution of the sample.

(13) Presence or absence of stretching (shrinkage)
A sample of 10 cm × 10 cm is cut out from an arbitrary portion of the thermoplastic resin film in an arbitrary direction, and the length of four sides is measured with a caliper. Thereafter, the sample was sandwiched between polyimide films (manufactured by Toray DuPont Co., Ltd., 25 μm), heated in an oven at 250 ° C. for 1 hour, taken out and cooled, and then the length of the four sides of the sample was measured again with a caliper. Was determined by the following equation.
Shrinkage (%) = (length of side before heating−length of side after heating) / length of side before heating × 100
The measurement was performed at n = 5, and the average of the shrinkage rates in the vertical and horizontal directions of the cut sample was determined and evaluated according to the following criteria.
Unstretched: Shrinkage rate is less than 1% in both longitudinal and transverse directions Uniaxial stretching: Shrinkage rate is 1% or more in either longitudinal or transverse direction Biaxial stretching: Shrinkage rate is 1% or more in both longitudinal and transverse directions

(Reference Example 1) Production method of PPS resin 1 In an autoclave, 100 mol of sodium sulfide nonahydrate, 45 mol of sodium acetate and 25 l of N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP) were used. While charging and stirring, the temperature was gradually raised to a temperature of 220 ° C., and the contained water was removed by distillation. 95 mol of p-dichlorobenzene as a main component monomer and 5 mol of m-dichlorobenzene as a subcomponent monomer are added to the dehydrated system together with 5 liters of NMP, and nitrogen is added at a temperature of 170 ° C. at 3 kg / cm 3. After pressurizing and sealing in ² , 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 block polymer was collected by a wire mesh having a 150 mesh opening. The thus obtained small lumpy polymer is washed twice with distilled water at 90 ° C., then three times with an aqueous sodium acetate solution, washed once with distilled water, and dried at a temperature of 120 ° C. under reduced pressure. Thus, PPS resin 1 having a melting point of 265 ° C. was obtained.

(Reference Example 2) Production method of PPS resin 2 Same as Reference Example 1, except that 90 mol of p-dichlorobenzene was added as a main component monomer and 10 mol of m-dichlorobenzene was added as a subcomponent monomer together with 5 L of NMP. Thus, PPS resin 2 having a melting point of 250 ° C. was obtained.

(Reference Example 3) Production method of PPS resin 3 Same as Reference Example 1 except that 85 mol of p-dichlorobenzene was added as a main component monomer and 15 mol of m-dichlorobenzene was added as a subcomponent monomer together with 5 L of NMP. Thus, a PPS resin 3 having a melting point of 240 ° C. was obtained.

(Reference Example 4) Method for producing PPS resin 4 In an autoclave, 100 mol of sodium sulfide nonahydrate, 45 mol of sodium acetate, and 25 l of N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP) were used. While charging and stirring, the temperature was gradually raised to a temperature of 220 ° C., and the contained water was removed by distillation. Into the dehydrated system, 100 mol of p-dichlorobenzene as a main component monomer was added together with 5 liters of NMP, nitrogen was pressurized at a temperature of 170 ° C. at 3 kg / cm ² , and the temperature was raised. Polymerization was conducted at a temperature of 4 ° C. for 4 hours. After completion of the polymerization, the mixture was cooled, the polymer was precipitated in distilled water, and a small block polymer was collected by a wire mesh having a 150 mesh opening. The thus obtained small lumpy polymer is washed twice with distilled water at 90 ° C., then three times with an aqueous sodium acetate solution, washed once with distilled water, and dried at a temperature of 120 ° C. under reduced pressure. As a result, a PPS resin 4 having a melting point of 280 ° C. was obtained.

(Reference Example 6) Method for producing PPS resin 5 75% by mass of granules of PPS resin 2 and 25% by mass of FE9 (D50 = 6 μm, D90 = 11 μm) manufactured by Admatechs as silica particles were mixed and heated to 300 ° C. It is fed into a vented co-rotating twin-screw kneading extruder (manufactured by Nippon Steel Works, screw diameter 30 mm, screw length / screw diameter = 45.5), and melts at a residence time of 90 seconds and a screw rotation speed of 150 rotations / minute. It was extruded and discharged in a strand shape, cooled with water at a temperature of 25 ° C., and immediately cut to produce a chip, which was used as a film raw material (PPS resin 5).

(Example 1)
The PPS resin produced in Reference Example 4 was charged into a vented co-rotating twin-screw kneading extruder (manufactured by Nippon Steel Works, screw diameter 30 mm, screw length / screw diameter = 45.5) heated to 320 ° C. Then, the mixture was melt-extruded at a retention time of 90 seconds and a screw rotation speed of 150 revolutions / minute, discharged in a strand shape, cooled with water at a temperature of 25 ° C., and immediately cut to produce a chip made of the PPS resin of Reference Example 4. And dried under reduced pressure at 180 ° C. for 3 hours.

  Further, the PPS resin prepared in Reference Examples 1 to 3 was blended with the inorganic particles shown in Table 1, and a co-rotating twin-screw kneading extruder equipped with a vent heated to 300 ° C. (manufactured by Nippon Steel Works, screw diameter 30 mm, Screw length / screw diameter = 45.5), melt extruded at a retention time of 90 seconds and a screw rotation speed of 150 rotations / minute, discharged in a strand form, cooled with water at a temperature of 25 ° C., and immediately cut. In this way, a chip made of a PPS resin containing inorganic particles was prepared and dried under reduced pressure at 180 ° C. for 3 hours.

The PPS resin pellets (II raw material) of Reference Example 4 were extruded in a single-screw extruder (L / D = 28) set at an extrusion temperature of 320 ° C., and the formulations shown in Table 1 were prepared using Reference Examples 1 to 3, respectively. The inorganic particle-containing PPS resin pellets (raw material I) were respectively charged into a single screw extruder (L / D = 28) set at an extrusion temperature of 300 ° C., and a layer (II) composed of raw material II and a layer (I) composed of raw material I ) / II The raw material layer (II) is passed through a feed block laminating apparatus so as to have a three-layer structure having the thickness shown in Table 1 and guided to a T-die, extruded into a sheet shape, and a wire with respect to the entire width of the extruded sheet. A voltage was applied using a static electricity applying device, and the layer was brought into close contact with a casting drum cooled to 20 ° C. to be cooled and solidified to obtain a laminated sheet. The obtained laminated sheet was guided to a longitudinal stretching machine composed of rolls and stretched in the longitudinal direction (MD direction) under the conditions and magnifications shown in Table 1. Next, the film was stretched 3.8 times at a preheating temperature of 95 ° C. and a stretching temperature of 100 ° C. 3.8 times in a longitudinal direction (TD direction) using a tenter, and then heat-treated at 280 ° C. Subsequently, after performing 5% relaxation treatment in the transverse direction (TD direction) for 4 seconds in the relaxation treatment zone at 280 ° C., cooling to room temperature, removing the film edge, and applying a biaxially stretched film having a thickness shown in Table 1 Obtained.
Table 1 shows the properties of the obtained film. It was excellent in dielectric constant, heat resistance and workability, and had little transmission loss.

(Examples 2 to 7)
A biaxially stretched film having the thickness shown in Table 1 was obtained in the same manner as in Example 1 except that the raw materials of the layer (I) and the layer (II), the thickness of each layer, and the production method were as shown in Table 1.
Table 1 shows the properties of the obtained film. Compared with Example 1, the dielectric constant and the workability were excellent, and the transmission loss was smaller.

(Example 8)
A biaxially stretched film having the thickness shown in Table 1 was obtained in the same manner as in Example 1 except that the resin used for the layer (I) was PPS resin 5.

(Comparative Example 1)
The PPS resin pellets (II raw material) of Reference Example 4 were charged into a single screw extruder (L / D = 28) set at an extrusion temperature of 320 ° C., melted, guided to a T-die, extruded into a sheet shape, and extruded. A voltage was applied to the entire width by using a wire-type electrostatic application device, and was closely adhered to a casting drum cooled to 20 ° C. to be cooled and solidified to obtain a laminated sheet. The obtained laminated sheet was guided to a vertical stretching machine composed of rolls, and a biaxially stretched film made of PPS resin 4 and containing no inorganic particles was obtained in the same manner as in Example 1.
Table 1 shows the properties of the obtained film. As a result, the dielectric constant was inferior and the transmission loss was large as compared with the example.

(Comparative Example 2)
In addition, the PPS resin produced in Reference Example 4 was mixed with the inorganic particles shown in Table 1, and a vented co-rotating twin-screw kneading extruder (manufactured by Nippon Steel Works, screw diameter 30 mm, screw length heated to 320 ° C.) / Screw diameter = 45.5), melt extruded at a retention time of 90 seconds, screw rotation speed of 150 revolutions / minute, discharged in strand form, cooled with water at a temperature of 25 ° C., and immediately cut to obtain inorganic particles. The added PPS resin chip was produced, and dried under reduced pressure at 180 ° C. for 3 hours. This resin chip was used as a raw material for the layer (II) in a single screw extruder (L / D = 28) set at an extrusion temperature of 320 ° C., and a single screw extruded PPS resin pellets of Reference Example 4 (II raw material) set at an extrusion temperature of 320 ° C. A biaxially stretched film having a thickness shown in Table 1 was obtained in the same manner as in Example 1 except that the extruder was not charged into an extruder (L / D = 28).
Table 1 shows the properties of the obtained film. As compared with the examples, there were many defects, heat resistance and workability were poor, and transmission loss was large.
The details of the inorganic particles used in Examples and Comparative Examples are as follows.
CaCO ₃ : Calcium carbonate P-50 manufactured by Shiraishi Kogyo Co., Ltd. is passed through a sieve shaker (AS200 manufactured by Verder Scientific Co., Ltd.) so that the volume average particle diameter is 8 μm, D50 = 8 μm, D90 = 28 μm. It adjusted and used.
BaSO ₄ : Sakai Chemical Co., Ltd., BMH-60 (volume average particle diameter 7 μm, D50 = 7 μm, D90 = 17 μm) was used as it was.

  INDUSTRIAL APPLICABILITY The thermoplastic resin film of the present invention is not only excellent in heat resistance, electric insulation and / or heat insulation and film formation stability, but also has few defects, so that it can be used for electric / electronic parts, battery members, machine parts and automobile parts. Can be suitably used as an insulating material or a heat insulating material.

Claims (6)

A thermoplastic resin film containing a polyarylene sulfide resin as a main component, having a laminated structure of two or more layers, wherein at least one of the constituent layers has pores and a melting point of 275 ° C. or less ( (I) a thermoplastic resin film; The thermoplastic resin film according to claim 1, wherein the thermoplastic resin film to at least the diameter 50μm crater-like defect is characterized in that 20 or / m ² or less. The thermoplastic resin film according to claim 1 or 2, wherein the orientation parameter of the layer (II) other than the layer (I) of the thermoplastic resin film is 0.8 to 1.4. An electric / electronic part using the thermoplastic resin film according to claim 1. An insulating material using the thermoplastic resin film according to claim 1. The thermoplastic resin film according to claim 1, wherein the film is biaxially stretched.