JP2018083415A - Laminate film, and production method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate film that is excellent in heat resistance, electrical insulation, and stability in production, and achieves a low dielectric constant and a thin film.SOLUTION: A laminate film contains as a main component a thermoplastic resin having at least one of a nitrogen atom and a sulfur atom as the constituent element and a melting point or softening point of 270°C or higher. At least one layer of layers constituting the laminate film is a layer (I) containing inorganic particles. The layer (I) has one or more peaks in each region of a region of 0.15 μm or more and less than 3 μm and a region of 3 μm or more and 20 μm or less in a size distribution of the inorganic particles contained in the layer (I). The laminate film has a dielectric constant of 2.5 or less and a thickness of 15-150 μm.SELECTED DRAWING: None

Description

  The present invention relates to a laminated film having excellent heat resistance and electrical insulation, excellent film forming stability, a low dielectric constant, and a thin film.

Films made of thermoplastic resins such as polyarylene sulfide, polyetherimide, polyethylene naphthalate, polyamide, polyimide, polyetheretherketone, liquid crystal polymer, and fluororesin are excellent in heat resistance and electrical insulation. -It is suitably used for insulating materials and heat insulating materials for electronic parts, battery members, machine parts and automobile parts. In recent years, with the development of the wireless communication field such as smartphones, tablets, and game devices, in order to improve the information processing speed, the dielectric constant of high-frequency circuit board materials has been reduced, and the substrate material has been made into a film with the miniaturization of equipment. It is being considered.
As a substrate film, a film made of polyimide, liquid crystal polymer, and polyarylene sulfide (hereinafter abbreviated as PPS) has been studied. However, the problem is that the high-frequency characteristics are inferior and the film is expensive. Further, although fluorine films have been studied, the high-frequency characteristics are excellent, but the problem is that the linear expansion coefficient is high and the adhesive processability is poor.
Therefore, the idea was to improve the high-frequency characteristics by making a relatively inexpensive PPS film porous. As a method for making a PPS film porous, a method has been proposed in which a component soluble in a solvent is mixed with the raw material of the film to form a film and then washed with a solvent to form pores (Patent Document 1). Since a soluble component is dispersed with a small dispersion diameter, it is a problem that the effect of reducing the dielectric is low. Moreover, although the method of mixing a foaming agent with a film raw material and forming a void | hole using a carbon dioxide is proposed (patent document 2), since a foaming ratio is high, a film turns into a film and heat conductivity falls. There was a problem.
In addition, a technique has been proposed in which fine particles are blended into the raw material of the PPS film to form vacancies during biaxial stretching (Patent Document 3). The problem is that the effect is low.

Japanese Patent Laid-Open No. 2015-13913 JP2013-206818A Japanese Patent Laying-Open No. 2015-98577

  An object of the present invention is to solve the above-described problems. An object of the present invention is to provide a laminated film that is excellent in heat resistance and electrical insulation, has excellent film forming stability, has a low dielectric constant, and can be thinned.

  The laminated film of the present invention has the following configuration in order to solve the above problems. That is, as a molecular constituent element, a laminated film mainly composed of a thermoplastic resin having a melting point or softening point of at least 270 ° C. having at least one of a nitrogen atom or a sulfur atom, and at least of the layers constituting the film One layer is a layer (I) containing inorganic particles, and the particle size distribution of the inorganic particles contained in the layer (I) has one or more peaks in each region of 0.15 μm to less than 3 μm and 3 μm to 20 μm. And having a dielectric constant of 2.5 or less at 23 ° C. and 65% RH, and a thickness of 15 to 150 μm.

Since the laminated film of the present invention is excellent in heat resistance and electric insulation, it can be suitably used as an electric / electronic device, a battery member, a machine part and an automobile part.

The laminated film of the present invention contains, as a main component, a thermoplastic resin having a melting point or softening point of at least 270 ° C. having at least one of a nitrogen atom and a sulfur atom as a molecular constituent element. Here, the melting point refers to the transition temperature of the solid / liquid of the resin, and the softening point refers to the temperature at which the thermoplastic resin begins to be substantially deformed by heating. Moreover, a main component means the component which occupies 60% or more among the resin compositions which comprise a film. By having the above thermal characteristics, excellent heat resistance can be exhibited. When the melting point or softening point is lower than 270 ° C., the film tends to be deteriorated when used in a high temperature environment of 180 ° C. or higher, and mechanical characteristics and electrical characteristics may be lowered. The higher the melting point or softening point, the better the heat resistance, but it is preferably 350 ° C. or lower from the viewpoint of productivity. The melting point can be evaluated by a differential scanning calorimeter, and the softening point can be evaluated by a method described later using a thermomechanical analyzer. Examples of the thermoplastic resin include polyamide resin, polyetherimide (PEI), thermoplastic polyamideimide resin, aromatic-containing vinyl resin (ABS, etc.), polyarylene sulfide resin (polysulfone, polyethersulfone, polyphenylene sulfide, etc.). It is preferably at least one selected from the group consisting of Among these, at least one selected from polyarylene sulfide, polyamide, and polyetherimide is preferable from the viewpoint of heat resistance and insulation, and a polyarylene sulfide resin is preferable from the viewpoint of workability and productivity. To most preferred.
The polyarylene sulfide resin used for the laminated film of the present invention refers to a copolymer having a repeating unit of-(Ar-S)-. Examples of Ar include units represented by the following formulas (A) to (K).

(R1 and R2 are substituents selected from hydrogen, an alkyl group, an alkoxy group, and a halogen group, and R1 and R2 may be the same or different.)
As the repeating unit, a p-arylene sulfide unit represented by the above chemical formula 1 is preferable, and typical examples thereof include polyphenylene sulfide, polysulfone, polyether sulfone, polyphenylene sulfide sulfone, polyphenylene sulfide ketone and the like. Particularly preferred p-arylene sulfide units are preferably p-phenylene sulfide units from the viewpoint of film properties and economy.

  The polyarylene sulfide resin used in the present invention is preferably composed of 80 mol% or more and 99.9 mol% or less of p-phenylene sulfide units represented by the following structural formula as main structural units. By setting it as said composition, the outstanding heat resistance and chemical-resistance can be expressed.

  Moreover, it can also copolymerize with a copolymerization unit in 0.01 mol% or more and 20 mol% or less of a repeating unit.

  Preferred copolymer units are

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

(Wherein 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 copolymerization component is not particularly limited, but is preferably a random copolymer.

The laminated film of the present invention has a layer (I) containing inorganic particles in at least one layer constituting the film. Voids can be efficiently formed by the inorganic particles contained in the layer (I), and the laminated film can be made low dielectric.
The laminated film of the present invention preferably has a laminated structure of two or more layers. By having a layer structure of two or more layers, the stretchability of the laminated film itself is improved, the tearing is suppressed, and the productivity can be improved. As the laminated structure, when the layer (I) and the layer having a composition different from the layer (I) are (II), two layers (I) / (II), (I) / (II) / (I), (II) / (I) / (II), (II) / (I) / (II) / (I), (II) / (I) / (II) / (I) / (II ) And the like, but is not limited thereto. Moreover, it can also be set as the layer structure which added the layer which consists of a composition different from (I)-(II) further.
The other layer (II) constituting the laminated film of the present invention may or may not contain inorganic particles.
When the layer (II) of the laminated film of the present invention contains particles, the concentration of the particles is preferably 0.01 to 5% by mass, and more preferably 0.01 to 1% by mass. By setting it as said density | concentration, while extending | stretching a film, while exhibiting the function as a support body of layer (II), the insulation as a laminated | multilayer film can be improved. When the concentration of the particles contained in the layer (II) exceeds 5% by mass, the film cannot withstand the stress applied to the film at the time of stretching, and the film tends to break, so that the film-forming stability is impaired, or the insulation May decrease.
When inorganic particles are contained in the other layer (II) constituting the laminated film of the present invention, the volume average particle size is 0.15 to 20 μm, and 0.3 to 15 μm from the viewpoint of film formation stability. It is more preferable that the thickness is 0.5 to 10 μm.
The thickness of the laminated film of the present invention is 15 to 150 μm, more preferably 25 to 150 μm, and further preferably 25 to 125 μm from the viewpoint of productivity and practical use.
If the thickness exceeds 150 μm, the heat conductivity is lowered, so that heat generated during transmission is difficult to escape, and deformation of the film due to heat is likely to occur. When the thickness is 15 μm or less, the strength as a film is lowered, and film formation stability may be lowered. The film thickness and layer thickness can be controlled by adjusting the feed rate of raw materials using particles described later when obtaining an unstretched sheet. Moreover, film thickness and layer thickness can be evaluated by the method mentioned later.
Examples of inorganic particles that can be used in the laminated film of the present invention include alumina ceramics such as alumina, silica, titania, zirconia, magnesia, ceria, yttria, zinc oxide, and iron oxide, and silicon nitride, titanium nitride, and boron nitride. Nitride ceramics, silicon carbide, calcium carbonate, aluminum sulfate, barium sulfate, potassium titanate, talc, kaolin clay, kaolinite, halloysite, pyrophyllite, montmorillonite, sericite, mica, amicite, bentonite, asbestos, zeolite Inorganic compounds such as ceramics such as calcium silicate, magnesium silicate, diatomaceous earth, and silica sand, and glass fiber. One kind of particles may be used, or a plurality of kinds may be mixed and used.
The inorganic particles used in the laminated film of the present invention can be subjected to surface treatment within a range that does not impair the physical properties of the laminated film.
The dielectric constant of the inorganic particles that can be used in the laminated film of the present invention is preferably 3.0 or less, more preferably 2.0 or less at a frequency of 10 GHz under a temperature of 20 ° C. and 65% RH. . Since the inorganic particles contained in the film have the above dielectric constant, the laminated film can be further reduced in dielectric constant. When the dielectric constant is 3.0 or more, the low dielectric effect due to void formation is offset by the dielectric constant of the particles, and the low dielectric effect as a film may be reduced. Examples of the particles having a dielectric constant of 3.0 or less include zinc oxide and calcium carbonate. The dielectric constant of the inorganic particles can be evaluated by a method described later.

The inorganic particles contained in the layer (I) of the laminated film of the present invention are preferably selected from those having an average particle diameter of 0.15 to 20 μm, more preferably 0.3 to 15 μm. More preferably, it is selected from those having a thickness of 5 to 10 μm. By using particles having the above average particle diameter, it is possible to suppress particle aggregation and efficiently form voids. If the average particle size is smaller than 0.15 μm, it tends to be a coarse product due to aggregation of the particles, which may cause film breakage during film formation, or may reduce the effect of lowering the dielectric due to the small voids. Moreover, since the ratio of the particle diameter with respect to the thickness of a film will become large when larger than 20 micrometers, film forming stability may be impaired.
The particle size distribution of the inorganic particles contained in the layer (I) of the laminated film of the present invention is characterized by having one or more peaks in each region of 0.15 μm or more and less than 3 μm and 3 μm or more and 20 μm or less. Here, having one or more peaks means that there are two or more distinct vertices and one or more valleys between the vertices when the particle size distribution is plotted by volume frequency and particle diameter. Sure. By having the above particle size distribution, the film can be efficiently reduced in dielectric strength when the above-mentioned thickness is achieved, and the strength of the film can be maintained. In the case where the peak of the particle size distribution is only 0.15 μm or more and less than 3 μm or only 3 μm or more and 20 μm or less, and the film is confirmed only in one of the above ranges, void formation is insufficient and the low dielectric effect of the film is low or large Since voids are formed, the strength of the film may be lowered, which is not preferable in practice. The particle size distribution preferably has one or more peaks in each region of 0.3 μm or more and less than 3 μm and 5 μm or more and 15 μm or less, and one or more in each region of 0.5 μm or more and less than 3 μm and 5 μm or more and 10 μm or less. It is particularly preferred to have
The particles used in the layer (I) and the layer (II) of the laminated film of the present invention preferably have a content of particles having a particle diameter of more than 50 μm of 3% by volume or less, more preferably 1% by volume or less. preferable. When particles of 50 μm or more are included, it may be a pressurizing factor at the time of melt extrusion, or it may be a cause of film breakage at the time of stretching and productivity may be lowered.
It is preferable that the density | concentration of the particle | grains contained in layer (I) of the laminated | multilayer film of this invention is 1-50 mass%, 5-45 mass% is more preferable, 10-35 mass% is further more preferable. By setting the particle concentration within the above range, voids can be efficiently formed, and the film can be made low dielectric. When the particle concentration is less than 1% by mass, voids may be difficult to be formed because the particle concentration is low during film production to be described later. On the other hand, if the particle concentration exceeds 50% by mass, the amount of resin is reduced, so that tearing tends to occur during film production.
The average particle size and particle size distribution / concentration of the particles contained in layer (I) and layer (II) are determined by removing the desired layer from the film using a knife or microplane and ashing at 500 ° C. It can be confirmed by analyzing the particle size distribution of the charcoal collected after removing the ash as the particle size distribution of the inorganic particles contained in the target layer. Particles with the above particle size distribution can be obtained by classifying synthetic or natural mined particles using a sieve until the desired distribution is obtained after grinding.
The dielectric breakdown voltage of the laminated film of the present invention is preferably 101 to 250 kv / mm, and more preferably 120 to 250 kV / mm. The higher the breakdown voltage, the better. However, the upper limit is 250 kV / mm in consideration of the realizable range. The dielectric breakdown voltage is a limit voltage value when the applied voltage is increased until dielectric breakdown occurs, and can be measured based on JIS C2151 (2006). If the dielectric breakdown voltage is lower than 101 kV / mm, when the laminated film is used as an insulating material, sufficient insulation may not be exhibited, and it may not be used. In order to make the breakdown voltage within the above range, it can be achieved by having the layer configuration and the layer structure described above. The dielectric breakdown voltage can be evaluated by a method described later.
The laminated film of the present invention has a dielectric constant at a frequency of 10 GHz at a temperature of 23 ° C. and 65% RH of 2.5 or less, and more preferably 2.3 or less. By having the above characteristics, when used as a circuit board material in a high frequency region, it is possible to reduce the strange capacity of the insulating material, so that transmission loss can be effectively suppressed. If the dielectric constant is greater than 2.5, transmission loss may increase when used as a substrate material. The lower the dielectric constant, the better, but the realizable range is 1.5 or more. In order to make the dielectric constant within the above range, the composition and characteristics of the laminated film can be achieved by the above-described configuration. The dielectric constant can be evaluated by a method described later.
In the laminated film of the present invention, the average value of the breaking strength in the longitudinal direction and the transverse direction of the film at 25 ° C. is preferably 100 N / 10 mm or more, more preferably 110 N / 10 mm or more, and 120 N / 10 mm or more. More preferably it is. By setting the breaking strength of the film in the above range, it is possible to maintain the conveyance tension in the processing when the film is used with the base material, and to suppress the yield. When the breaking strength is 100 N / 10 mm or less, the film at the time of film conveyance is easily broken and the yield may be increased. The higher the breaking strength, the better. However, the realizable range is 1000 N / 10 mm or less. The breaking strength can be evaluated by a method described later. The breaking strength of the film can be achieved by using the aforementioned particles.
The thermal conductivity of the laminated film of the present invention is preferably 0.1 W / m · ° C. or more, more preferably 0.15 W / m · ° C. or more, and 0.2 W / m · ° C. or more. Is particularly preferred. By having said heat conductivity, the heat | fever generate | occur | produced by electricity supply when it uses as a base material can be spread | diffused efficiently. When the thermal conductivity is less than 0.1 W / m · ° C., heat is confined to the base material and the members adjacent thereto, which is likely to cause deformation and thermal deterioration, which is not preferable for practical use. The higher the thermal conductivity, the better, but the realizable range is 0.4 W / m · ° C. or less. Thermal conductivity can be achieved by using the above-mentioned particles and setting the film thickness as described above. The thermal conductivity can be evaluated using a method described later.
The transmission loss at 10 GHz at 23 ° C. and 65% RH of the laminated film of the present invention is preferably less than 25%, and more preferably less than 20%. Transmission loss represents the degree of deterioration of a signal flowing on a communication line. If the transmission loss is greater than 25%, the input signal on the circuit line is greatly deteriorated, and it becomes difficult to apply it as a member of a device during large-capacity communication. The lower the lower limit of transmission loss, the better. The transmission loss can be controlled within the above range by setting the laminated film to the above-described dielectric constant. The transmission loss can be evaluated by the method described later.
In the laminated film of the present invention, the average value of strength retention in the film longitudinal direction and width direction after treatment at 200 ° C./1000 hours is preferably 65 to 100%, more preferably 75 to 100%. By setting the strength retention within the above range, the mechanical properties and electrical properties of the laminated film when used for a long time at high temperature can be maintained. When the strength retention is less than 60%, the long-term heat resistance is inferior, and when used at a high temperature for a long time, cracks may occur due to deterioration or the electrical characteristics may deteriorate. In order to make a strength retention into said range, it can achieve by using the above-mentioned thermoplastic resin film. The strength retention can be evaluated by a method described later.
The resin composition constituting the laminated film of the present invention can be used by blending a resin other than the polyarylene sulfide resin within a range not impairing the effects of the present invention. Specific examples of such resins include polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polyamide resins, polyamideimide resins, polyketones, polyether ketones, polyether imides, and epoxy resins. However, it is not limited to this.

    The resin composition constituting the laminated film of the present invention can be used by blending an additive within a range not impairing the effects of the present invention. Specific examples of such additives include organic compounds, thermal decomposition inhibitors, thermal stabilizers, light stabilizers and antioxidants.

  The production method of the present invention will be described with reference to an example in which a polyarylene sulfide resin is used as a thermoplastic resin which is a preferred embodiment of the present invention.

A method for producing a polyarylene sulfide resin preferably used for the laminated film of the present invention will be described. Sodium sulfide and p-dichlorobenzene are blended and reacted in an amide polar solvent such as N-methyl-2-pyrrolidone (NMP) at high temperature and high pressure. If necessary, a copolymer component such as m-dichlorobenzene or trihalobenzene can also be included. Caustic potash or alkali metal carboxylate is added as a polymerization degree adjusting agent, and a polymerization reaction is performed at 230 to 290 ° C. After the polymerization, the polymer is cooled, and the polymer is filtered as a water slurry through a filter to obtain a wet granular polymer. An amide polar solvent is added to this granular polymer and washed by stirring at a temperature of 30 to 100 ° C., washed several times with ion exchange water at 30 to 80 ° C., and several times with an aqueous metal salt solution such as calcium acetate. After washing, drying is performed to obtain a granular polymer of polyarylene sulfide resin. This granular polymer and inorganic particles are mixed at an arbitrary ratio, put into an extruder with a vent set to 300 to 350 ° C, melt extruded into a strand, cooled with water at a temperature of 25 ° C, and then cut to produce a chip. And a raw material for the layer (I) containing inorganic particles. At this time, 1-100 mass parts is preferable with respect to 100 mass parts of granular polymers, and, as for the addition density | concentration of an inorganic particle, 5-80 mass parts is more preferable.
Moreover, only said granular polymer, or granular polymer, an inorganic particle, an additive, etc. are mixed in arbitrary ratios, it puts into the extruder with a vent set to 300-350 degreeC, melt-extrusion in the shape of a strand, temperature 25 degreeC After cooling with water, cutting is performed to produce a chip, which is used as a raw material for the other layer (II) having a composition different from that of the layer (I). These two types of chips were dried under reduced pressure at 180 ° C. for 3 hours, then supplied to two full-flight single-screw extruders each having a melting part set at 300 to 350 ° C., passed through a filter, and then melted. In the state, it is led by the laminating device at the upper part of the die so that it becomes 2 layers (lamination structure is (I) / (II), lamination ratio is (I) :( II) = 9: 1), then T-die type It is discharged from the die, and is brought into close contact while applying an electrostatic charge onto a cooling drum having a surface temperature of 20 to 70 ° C. to rapidly cool and solidify to obtain a substantially unoriented film.

  Next, in the case of biaxial stretching, the unstretched film obtained above is sequentially biaxially stretched in the range from the glass transition point (Tg) to the cold crystallization temperature (Tcc) of the polyarylene sulfide resin. After biaxial stretching with a biaxial stretching machine, one-stage or multi-stage heat treatment is performed at a temperature in the range of 150 to 280 ° C. to obtain a biaxially oriented film. Stretching methods include sequential biaxial stretching methods (stretching methods that combine stretching in each direction, such as a method of stretching in the width direction after stretching in the longitudinal direction), and simultaneous biaxial stretching methods (in the longitudinal direction and the width direction). The method of extending | stretching simultaneously), or the method which combined them can be used. Here, a sequential biaxial stretching method in which stretching in the longitudinal direction first and then in the width direction is illustrated. The unstretched film is heated with a heated roll group, and stretched in the longitudinal direction (MD direction) by 2.8 to 5.0 times, more preferably 3.0 to 4.2 times, one stage or two or more stages. (MD stretching). The stretching temperature is in the range of Tg to Tcc, preferably (Tg + 5) to (Tcc-10) ° C. Thereafter, it is cooled by a cooling roll group of 20 to 50 ° C.

  As a stretching method in the width direction (TD direction) following MD stretching, for example, a method using a tenter is common. The both ends of this film are gripped with clips, guided to a tenter, and stretched in the width direction (TD stretching). The stretching temperature is preferably Tg to Tcc, more preferably (Tg + 5) to (Tcc-10) ° C. The draw ratio is 2.8 to 5.0 times, preferably 3.0 to 4.5 times from the viewpoint of the flatness of the film.

Next, an operation (heat setting treatment) of heat-setting the stretched film under tension is performed. The temperature of the heat setting treatment is the same at the beginning and end of the heat treatment zone, and the heat treatment is performed at the same temperature, or the heat treatment treatment is performed in either one-stage heat setting or multistage heat setting in which heat treatment is performed at different temperatures in the first half and the second half of the heat treatment zone. . In the case of performing one-stage heat setting, the heat setting temperature is preferably 160 to 280 ° C. Moreover, when performing heat processing by multistage heat fixation, 150 degreeC-220 degreeC is preferable, and, as for the heat fixation temperature of the 1st step | paragraph (first half), 150 degreeC-210 degreeC is more preferable. By setting the first stage heat fixing temperature within the above range, it is possible to reduce the area magnification while maintaining the flatness of the film. The second stage (second half) heat setting temperature is preferably 220 to 280 ° C, more preferably 230 to 275 ° C. Here, when the second stage heat fixing temperature is less than 220 ° C., the thermal dimensional stability of the film may deteriorate, and when it exceeds 280 ° C., it approaches or exceeds the melting temperature of the polyarylene sulfide resin constituting the film. Therefore, it may be difficult to extract the film from the stretching apparatus by fusing to a clip that fixes both ends of the film during film formation. After the heat setting treatment, the film is cooled and rolled up to room temperature, if necessary, in the longitudinal and width directions, if necessary, to obtain a biaxially stretched laminated film.
Since the laminated film of the present invention is excellent in heat resistance and electrical insulation, it can be suitably used as insulating paper for automobiles, various parts of electric / electronic materials, and various motors. Moreover, since it has low dielectric properties and can be made thin, it can be suitably used particularly for circuit boards, flexible flat cables, various radars, film carriers, high-density magnetic tape materials, wire coating agents, film capacitors, and the like.
[Measurement method of characteristics]
(1) Layer thickness and layer structure of each layer constituting the laminate film and the laminate film The laminate film fixed on the sample stage of the scanning electron microscope is 10 to ³ Torr, voltage 0.25 KV, current using a sputtering apparatus. After performing the ion etching treatment at 12.5 mA 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 3,000 using a scanning electron microscope. .

From the image obtained by observation, the thickness of the laminated film and the thickness of the layers constituting the laminated film were measured. When the whole thickness direction of the laminated film cannot be confirmed at the above magnification, several images are taken in the thickness direction, and the whole image is confirmed by joining the images.
The sample used for the measurement of thickness selected 10 places in total of arbitrary places, and made the average of the measured value of 10 samples the film thickness of the sample, and the thickness of the layer which comprises a film.
(2) Content (concentration) of inorganic particles and average particle size / particle size distribution a. Content (concentration)
After confirming the thickness of the laminated film and each layer using the method of (1), using a microplane and an electronic micrometer (manufactured by Anritsu Co., Ltd., K-312A type, needle pressure 30 g) at 23 ° C. and 65% RH The target layer is scraped off from the laminated film while checking the thickness in an atmosphere. The scraped sample is put in a weighing 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. The crucible was cooled and weighed, the weight after heating was measured, the weight before and after heating was inserted into the following formula, and the content of inorganic particles contained in the film was calculated. The measurement was performed at n = 3. When the average value was larger than 0, the layer was judged to contain particles, and the average value was used as the particle concentration of the sample. The sample amount was adjusted so that the mass of the residue was in the range of 100 to 200 mg.
Content of inorganic particles (% by mass) = weight after heating (mg) / weight before heating (mg) × 100
b. Particle size distribution and peak value a. The residue obtained in the above was mixed with purified water and adjusted so that the transmittance was about 90%. The dispersion was subjected to ultrasonic treatment for 4 minutes before measurement under the conditions of a laser beam wavelength of 780 nm and a measurement temperature of 23 ° C. using a laser beam diffraction / scattering particle size distribution measurement device (Microtrack MT3000, manufactured by Nikkiso). Measured according to JIS Z8825-1: 2001, and the peak value was read from the particle size distribution of the sample.

(3) Dielectric constant a. 1 g of particles of dielectric constant particles are weighed, and a 20 kPa load is applied for 1 minute to form a disk-shaped measurement sample having a diameter of 25 mm and a thickness of 1.5 ± 0.5 mm. This measurement sample is attached to ARES (manufactured by TA Instruments) equipped with a dielectric constant measurement jig (electrode) having a diameter of 25 mm. Using a 4284A Precision LCR meter (manufactured by Hewlett Packard) with a load of 250 g / cm 2 at a measurement temperature of 30 ° C., measurement was performed in an environment of 10 GHz, a temperature of 23 ° C., and a humidity of 65% RH. .
b. Dielectric constant of laminated film 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 minute material (width: 2.7 mm × length: 45 mm) was inserted into the cavity resonator, and measurement was performed in a temperature 23 ° C., humidity 65% RH environment.

(4) Dielectric breakdown voltage Measured according to JIS C2151, using an AC dielectric breakdown tester (manufactured by Kasuga Electric Co., Ltd., AC 30 kV). The size of the test piece was a square of 25 cm × 25 cm, and the sample was conditioned in an environment of 23 ° C. and 65% RH and measured at a frequency of 60 Hz and a boosting speed of 1000 V / sec. The shape of the electrode used is a cylindrical shape with a lower electrode serving as a pedestal of φ75 mm and a height of 15 mm, and an upper electrode having a cylindrical shape of φ25 mm and a height of 25 mm. As for any electrode, the surface on the side sandwiching the test piece was chamfered with R3 mm. The measurement was performed 10 times for each sample, and the dielectric breakdown voltage (kV / mm) was calculated by inserting the average value of the voltage value at which breakdown occurred and the average value of the thickness of the sample into the following equation.
Dielectric breakdown voltage (kV / mm) = average value of breakdown voltage value (kV) / average thickness value (mm)
(5) Breaking strength
Using an Instron type tensile testing machine (Orientec Co., Ltd. film tensile strength automatic measuring device “Tensilon AMF / RTA-100”), the sample size is 10 mm in a width of 23 ° C. and 65% RH. × Evaluation was performed at a test length of 100 mm and a pulling speed of 300 mm / min. The measurement was performed 10 times for each of the longitudinal direction and the transverse direction of the film, and the obtained evaluation values were inserted into the following formula to calculate the average value.
Breaking strength (N / 10 mm) = ((average value measured 10 times in the MD direction: N / 10 mm) + (average value measured 10 times in the TD direction: N / 10 mm)) / 2
(6) Thermal conductivity a. Specific heat capacity Cp
Using a differential scanning calorimeter (DSC-7, manufactured by Perkin Elmer), sapphire was used as a standard material according to JISK7123-1987, and the specific heat capacity (J / (kg · K)) at 25 ° C. was measured. . The measurement was performed at n = 5, and the average value was defined as the specific heat capacity Cp (J / (kg · K)) of the sample.
b. Thermal diffusivity α
The thermal diffusivity (m ² / S) was measured using ai-Phase Mobile 1u (a thermal conductivity measurement system manufactured by I-Phase Co., Ltd.). The measurement was performed at n = 5, and the average value was defined as the thermal diffusivity α (m ² / S) of the sample.
c. Density ρ
The film is cut into a size of 50 mm × 40 mm, and density is measured by Archimedes method at room temperature of 23 ° C. and relative humidity of 65% using a specific gravity measurement kit (AD-1653-BM, manufactured by A & D Co., Ltd.). Measurements were made. The measurement was performed at n = 3, and the average value was taken as the sample density ρ (kg / m ³ ).
d. Thermal conductivity λ
The measured values obtained in ac were inserted into the following formula, and the thermal conductivity λ (J / (s · m · k) was obtained.
Thermal conductivity λ (J / (s · m · k) =
Specific heat capacity Cp (J / (kg · K)) x thermal diffusivity α (m ² / S) x density ρ (kg / m ³ )
(7) Transmission loss
A sample obtained by depositing copper with a thickness of about 2 μm on the surface of the laminated film was used as a sample, and a microwave network analyzer (Agilent Technology “8722ES”) was used, and a cascade microtech probe (ACP 40-250) at 10 GHz. The transmission loss (%) was measured. The measurement was carried out immediately after the sample was allowed to stand for 24 hours in an environment of temperature 23 ° C. and humidity 65% RH, and evaluated according to the following criteria.
A: Less than 20% B: 20% or more and less than 25% C: 25% or more
(8) Film-forming property a. Film formation stability The film formation described in Examples and Comparative Examples was performed continuously for 5 hours, and the number of occurrences of film breakage (including breakage during longitudinal stretching, transverse stretching, and heat setting treatment) was as follows. Judged in.
A: No tear
B: Frequency of occurrence of tears 1 to 2 times C: Frequency of occurrence of tears 3 to 10 times
D: The occurrence frequency of breakage is 11 times or more. B. After melt filtration with a filter having an opening of 80 μm in an extrusion stable molten state, the film formation described in Examples and Comparative Examples is continuously performed for 5 hours, and the test is started. The resin pressure immediately after and the resin pressure at the end of the test were applied to the following equation, the resin pressure fluctuation amount ΔP was determined, and the value was evaluated as the standard of production stability and evaluated according to the following criteria.

Resin pressure fluctuation amount (ΔP) = resin pressure at the end of the test [MPa] −resin pressure immediately after the start of the test [MPa]
A: ΔP is 1 MPa or less B: ΔP is greater than 1 MPa and 2.0 MPa or less C: ΔP is greater than 2.0 MPa (9) Melting point or softening point of laminated film a. Melting point (℃)
According to JIS K7121-1987, using a Seiko Instruments DSC (RDC220) as a differential scanning calorimeter and a disk station (SSC / 5200) as a data analyzer, weighed 3 mg of sample on an aluminum saucer at room temperature. To 340 ° C. at a temperature rising rate of 20 ° C./min, and the peak temperature of the endothermic peak of melting observed at that time is measured. The measurement was carried out three times per sample, and the average of the obtained values was taken as the melting point (° C.) of the sample. In addition, when two or more peaks are confirmed, an average value is calculated for each peak.

b. Softening point (℃)
A circular sample having a diameter of 5 mm is cut out from an arbitrary portion of the laminated film to obtain a sample. This sample was heated on a thermomechanical analyzer (manufactured by Hitachi High-Tech Science Co., Ltd., SS6100) using a conical needle probe having a tip diameter of 0.5 mm at a load of 49 mN under a temperature rising condition of 10 ° C./min. The softening point is measured from a plot of probe penetration and heating temperature. The measurement was performed three times per sample, and the average value of the obtained values was defined as the softening point (° C.) of the sample.

(10) Heat-resistant laminated film The laminated film is cut to a width of 10 mm and a length of 250 mm in each of the MD direction and the TD direction to obtain a test piece, which is subjected to heat treatment for 1000 hours in a hot air oven set at a temperature of 200 ° C. The fracture strength before and after the heat treatment was measured, the strength retention was calculated from the following formula, and evaluated according to the following criteria. The breaking strength is set according to the method defined in JIS-C2151, using a Tensilon tensile tester, setting a 10 mm wide sample piece to a length between chucks of 100 mm, and conducting a tensile test at a tensile speed of 300 mm / min. Under these conditions, measurement was performed 10 times in the MD and TD directions, 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)
A: Strength retention is 75% or more B: Strength retention is 65% or more and less than 75% C: Strength retention is less than 65%

Reference Example 1 Production Method of Polyphenylene Sulfide Resin (Granule) Autoclave (maximum operating pressure: 14 MPa) with 100 moles of sodium sulfide nonahydrate, 45 moles of sodium acetate and 25 liters of N-methyl-2-pyrrolidone (Hereinafter abbreviated as NMP) was added, the temperature was gradually raised to a temperature of 220 ° C. with stirring, and the contained water was removed by distillation. In the system after the dehydration, 100 moles of p-dichlorobenzene as a main component monomer was added together with 5 liters of NMP, nitrogen was pressurized and sealed at 3 kg / cm ² at a temperature of 170 ° C., and the temperature was raised. Polymerization was carried out at a temperature of 4 ° C. for 4 hours. After completion of the polymerization, the polymer was cooled, the polymer was precipitated in distilled water, and a small polymer was collected with a wire mesh having a 150 mesh opening. The small polymer obtained in this way was washed twice with distilled water at 90 ° C., then washed three times with an aqueous sodium acetate solution, then washed once with distilled water, and dried at a temperature of 120 ° C. under reduced pressure. As a result, granules of polyphenylene sulfide (PPS) resin having a melting point of 280 ° C. were obtained.

(Reference Example 2) Production Method of Film Raw Material (PPS0) The PPS resin granules prepared in Reference Example 1 were bent at the same direction and rotated in the same direction with a biaxial kneading extruder (Nippon Steel Works, screw 30 mm in diameter, screw length / screw diameter = 45.5), melt-extruded at a residence time of 90 seconds and a screw rotation speed of 150 revolutions / minute, discharged into a strand, cooled with water at a temperature of 25 ° C., Immediately cutting was performed to produce a chip, which was used as a film raw material (PPS0).

(Reference Example 3) Production Method of Film Raw Material (PPS1) Two types of zinc oxide (LPZINC11 (average particle size 11 μm) and LPZINC2 (average particle size 2 μm) with different average particle sizes, manufactured by Sakai Chemical Co., Ltd., both dielectrics The rate is 1.7) for each 15% and 70% by mass of the PPS resin granules prepared in Reference Example 1 with a vented co-rotating twin-screw kneading extruder (made by Nippon Steel Works) heated to 320 ° C. , Screw diameter 30 mm, screw length / screw diameter = 45.5), melt-extruded at a residence time of 90 seconds and a screw rotation speed of 150 rotations / min, discharged into a strand, and cooled with water at a temperature of 25 ° C. Thereafter, cutting was performed immediately to produce a chip, which was used as a film raw material (PPS1).

(Reference Example 4) Production Method of Film Raw Material (PPS2) Two types of zinc oxide used were LPZINC11 (average particle size 11 μm) and fine zinc oxide (average particle size 0.2 μm, manufactured by Sakai Chemical Co., Ltd., dielectric constant 1 .7) A film raw material (PPS2) was obtained in the same manner as in Reference Example 3 except that it was changed to .7).

(Reference Example 5) Production Method of Film Raw Material (PPS3) The particles used were 2 types of silica (HF2001 (average particle size 5 μm, manufactured by Fuji Silysia Co., Ltd., dielectric constant 3.8) and OSCAL2725LW (average particle size 0. A raw material for film (PPS3) was obtained in the same manner as in Reference Example 3 except that 55 μm, Nissan Chemical Co., Ltd., dielectric constant 3.8) was used.

(Reference Example 6) Production Method of Film Raw Material (PPS4) The particles used were two types of calcium carbonate (P40 (average particle size 7 μm, manufactured by Shiraishi Kogyo Co., Ltd., dielectric constant 1.5) and CS-3NA (average particle size). A raw material for a film (PPS4) was obtained in the same manner as in Reference Example 3 except that the diameter was 1.5 μm, Ube Materials Co., Ltd., dielectric constant 1.5).

(Reference Example 7) Film raw material (PPS5)
A raw material for a film was prepared in the same manner as in Reference Example 3, except that two types of zinc oxide used were LPZINC20 (average particle size 20 μm, manufactured by Sakai Chemical Co., Ltd., dielectric constant 1.7) and LPZINC2 (average particle size 2 μm). (PPS5) was obtained.

(Reference Example 8) Film raw material (PPS6)
A film raw material (PPS6) was obtained in the same manner as in Example 3 except that 1% by mass of zinc oxide 1 type (LPZINC2) and 99% by mass of the PPS resin granules prepared in Reference Example 1 were blended.

(Reference Example 9) Film raw material (PPS7)
In the same manner as in Reference Example 3, except that 22.5% by mass of each of two types of zinc oxides (LPZINC11 and LPZINC2) having different average particle diameters and 55% by mass of the PPS resin granules prepared in Reference Example 1 were blended. A raw material (PPS7) was obtained.

(Reference Example 10) Film raw material (PPS8)
The raw material for film (PPS8) was used in the same manner as in Reference Example 3 except that the particles to be used were two kinds of calcium carbonate (P40 and white glaze (average particle size 0.1 μm, manufactured by Shiraishi Kogyo Co., Ltd., dielectric constant 1.5). )

(Reference Example 11) Film raw material (PPS9)
A raw material for film (PPS9) was obtained in the same manner as in Reference Example 3, except that two types of zinc oxide used were LPZINC30 (average particle size 30 μm, Sakai Chemical Co., Ltd., dielectric constant 1.7) and LPZINC2. .

(Reference Example 12) Film raw material (PPS10)
A raw material for film (PPS10) was obtained in the same manner as in Example 3 except that 30% by mass of zinc oxide type 1 (LPZINC11) and 70% by mass of the PPS resin granules prepared in Reference Example 1 were blended.

(Reference Example 13) Film raw material (PPS11)
A film raw material (PPS11) was obtained in the same manner as in Example 3 except that 30% by mass of zinc oxide 1 type (LPZINC2) and 70% by mass of the PPS resin granules prepared in Reference Example 1 were blended.
(Reference Example 14) Film raw material (PEI1)
2 types of zinc oxide with different average particle sizes (LPZINC11 (average particle size 11 μm) and LPZINC2 (average particle size 2 μm), manufactured by Sakai Chemical Co., Ltd., both having a dielectric constant of 1.7) are each 15% by mass, softened 70 mass% of PEI resin (ULTEM1010, manufactured by SAVIC Innovative Plastics Co., Ltd.) having a point of 340 ° C. was introduced into the vented co-rotating twin-screw kneading extruder of Reference Example 3 heated to 350 ° C., and the residence time was 90 The melt was extruded at a screw speed of 150 revolutions / minute, discharged in a strand form, cooled with water at a temperature of 25 ° C., and immediately cut to produce a chip, which was used as a film raw material (PEI1).
(Reference Example 15) Film raw materials (PEN0 and PEN1)
To a mixture of 100 parts by weight of dimethyl 2,6-naphthalenedicarboxylate and 60 parts by weight of ethylene glycol, 0.03 part by weight of manganese acetate tetrahydrate salt is added and gradually heated from 150 ° C. to 240 ° C. The transesterification was carried out while raising the temperature. In the middle, when the reaction temperature reached 170 ° C., 0.024 parts by weight of antimony trioxide was added. When the reaction temperature reached 220 ° C., 0.042 parts by weight (corresponding to 2 mmol%) of 3,5-dicarboxybenzenesulfonic acid tetrabutylphosphonium salt was added. Thereafter, a transesterification reaction was carried out. After the transesterification reaction, 0.023 parts by weight of trimethyl phosphate was added. Next, the reaction product is transferred to a polymerization reactor, heated to a temperature of 290 ° C., and subjected to a polycondensation reaction under a high reduced pressure of 0.2 mmHg or less. Polyethylene having an intrinsic viscosity of 0.65 dl / g and a melting point of 265 ° C. A chip of -2,6-naphthalate (PEN0) was obtained. 70 mass% of this PEN chip and two kinds of zinc oxides having different average particle diameters (LPZINC11 (average particle diameter 11 μm) and LPZINC2 (average particle diameter 2 μm), manufactured by Sakai Chemical Co., Ltd., both having a dielectric constant of 1.7) Were added to the vented same-direction rotating twin-screw kneading extruder of Reference Example 3 heated to 290 ° C., and melt-extruded at a residence time of 90 seconds and a screw speed of 150 revolutions / minute to form a strand. After discharging and cooling with water at a temperature of 25 ° C., cutting was performed immediately to produce a chip, which was used as a film raw material (PEN1).

(Examples 1-8, Comparative Example 3)
The chips obtained in Reference Examples 2 to 10 were each vacuum-dried at 180 ° C. for 3 hours, then separately supplied to two single-screw extruders in the combinations shown in Table 1, heated to 320 ° C. and melted And then melt-filtered with a filter having an opening of 80 μm, and then two layers (layer configuration is (I) / (II), stacking ratio is (I) :( II) = 9: 1) Then, it was discharged from a T-die die, and was tightly cooled and solidified while applying an electrostatic charge to a cast drum having a surface temperature of 25 ° C. to obtain a 450 μm unstretched laminated sheet. Then, after preheating the obtained unstretched laminated sheet with a plurality of heating rolls heated to a surface temperature of 90 ° C., a heating roll heated to a surface temperature of 100 ° C. and a circumference provided next to the heating roll The film was stretched 3.3 times in the longitudinal direction (MD direction) between 30 ° C. cooling rolls with different speeds. The uniaxially stretched sheet thus obtained was stretched 3.3 times at a temperature of 95 ° C. in the longitudinal direction (TD direction) using a tenter, followed by heat treatment at 270 ° C., and subsequently at 270 ° C. In the relaxation treatment zone, 5% relaxation treatment was performed in the TD direction and then cooled to room temperature to obtain a laminated film having a thickness of 100 μm.

(Example 8)
A chip of PEI resin (ULTEM 1010, manufactured by SAVIC Innovative Plastics) having a softening point of 340 ° C. (PEI 0) and a chip of PEI 1 obtained in Reference Example 14 were each vacuum-dried at 180 ° C. for 3 hours, and then the combinations shown in Table 1 Are separately supplied to two extruders heated to 350 ° C., and in a molten state, two layers are formed by a laminating apparatus at the upper part of the die (the laminating configuration is (I) / (II), the laminating ratio is (I): (II) = 9: 1), followed by ejection from a T-die die, adhesion rapid cooling and solidification while applying an electrostatic charge to a cast drum having a surface temperature of 25 ° C., and an unstretched laminate of 450 μm A sheet was obtained.
Next, the obtained unstretched sheet was cut into a size of 100 mm × 100 mm, and using a film stretcher (Brookner, KARO-IV), the preheating and stretching temperature were both 230 ° C. and the preheating time was 1 minute, At a stretching rate of 5% / sec, a stretching ratio of 3.3 times in the longitudinal (MD) direction of the sheet and then 3.3 times in the transverse (TD) direction of the sheet, followed by heat treatment at 270 ° C., Subsequently, a relaxation treatment of 5% was performed at 270 ° C. in the TD direction and then cooled to room temperature to obtain a PEI film having a thickness of 100 μm.

(Comparative Example 1)
The chips obtained in Reference Examples 2 and 3 were vacuum-dried at 180 ° C. for 3 hours, then supplied to an extruder, discharged from a T-die die, and an electrostatic charge was applied to a cast drum having a surface temperature of 25 ° C. Adhesion was rapidly cooled and solidified to obtain an unstretched sheet of 750 μm. Next, stretching and heat treatment were performed in the same manner as in Example 1 to obtain a film having a thickness of 170 μm.

(Comparative Example 2)
The chips obtained in Reference Examples 2 and 3 were vacuum-dried at 180 ° C. for 3 hours, then supplied to an extruder, discharged from a T-die die, and an electrostatic charge was applied to a cast drum having a surface temperature of 25 ° C. Adhesion was rapidly cooled and solidified to obtain an unstretched sheet of 150 μm. Subsequently, the film was stretched in the same manner as in Example 1 to collect a 10 μm film. However, the film was broken at the time of transverse stretching, and a biaxially stretched film could not be collected.

  (Comparative Example 4) Except for using the chips obtained in Reference Examples 2 and 12, a 100 μm film was collected in the same manner as in Example 1, but the film was broken during transverse stretching, and the biaxially stretched film was Could not be collected.

(Comparative Example 5)
A 100 μm film was collected in the same manner as in Example 1 except that the chips obtained in Reference Examples 2 and 13 were used.

(Comparative Example 6)
A 100 μm film was collected in the same manner as in Example 1 except that the chips obtained in Reference Examples 2 and 14 were used.

(Comparative Example 7)
The PEN chips (PEN0) and PEN1 chips obtained in Reference Example 15 were vacuum-dried at 160 ° C. for 3 hours, respectively, and then placed in two extruders heated to 290 ° C. in the combinations shown in Table 1. Separately supplied, melt-filtered with a filter having an opening of 80 μm, and then laminated with a laminating apparatus at the upper part of the die (the laminating configuration is (I) / (II), the laminating ratio is (I) :( II) = 9: 1), and then discharged from a T-die die, and was rapidly cooled and solidified while applying an electrostatic charge to a cast drum having a surface temperature of 25 ° C. to obtain a 450 μm unstretched sheet. Next, after preheating the obtained unstretched laminated sheet with a plurality of heating rolls heated to a surface temperature of 130 ° C., a heating roll heated to a surface temperature of 100 ° C., and a circumference provided next to the heating roll The film was stretched 3.3 times in the longitudinal direction (MD direction) between 30 ° C. cooling rolls with different speeds. The uniaxially stretched sheet thus obtained was stretched 3.3 times at a temperature of 130 ° C. in a direction perpendicular to the longitudinal direction (TD direction) using a tenter, followed by heat treatment at 230 ° C. and subsequently 230 ° C. In the relaxation treatment zone, 5% relaxation treatment was performed in the TD direction and then cooled to room temperature to obtain a PEN film having a thickness of 100 μm.
Table 1 shows the property evaluation results of the laminated films obtained in Examples 1 to 8 and Comparative Examples 1 to 7.

Claims (11)

As a constituent element of the molecule, at least one of the layers constituting the film, which is a laminated film mainly composed of a thermoplastic resin having a melting point or softening point of at least 270 ° C. having at least one of a nitrogen atom or a sulfur atom A layer (I) containing inorganic particles, and the particle size distribution of the inorganic particles contained in the layer (I) has one or more peaks in each region of 0.15 μm or more and less than 3 μm and 3 μm or more and 20 μm or less. A laminated film having a dielectric constant of 2.5 or less and a thickness of 15 to 150 μm. The laminated film according to claim 1, wherein the concentration of the inorganic particles contained in the layer (I) is 1 to 50% by mass. The laminated film according to claim 1, wherein the thermoplastic resin is selected from one or more of polyarylene sulfide, polyamide, and polyetherimide. The laminated film according to claim 1, wherein the inorganic particles contained in the layer (I) have a dielectric constant of 3.0 or less. The laminated film according to claim 1, wherein the dielectric breakdown voltage is 101 to 250 kV / mm. The manufacturing method of the film of Claim 1 manufactured by passing through the process of forming the sheet | seat which has a laminated structure of two or more layers by coextrusion, and the process of biaxially stretching this sheet | seat in said order. The heat insulating material using the laminated | multilayer film in any one of Claims 1-5. The insulating material using the laminated | multilayer film in any one of Claims 1-5. A motor using the insulating material according to claim 8. A tape using the laminated film according to claim 1. A circuit board using the laminated film according to claim 1.