JP2020139151A - Thermoplastic resin film and method for producing the same - Google Patents

Abstract

To provide a thermoplastic resin film that is excellent in heat resistance, electric characteristics and workability.SOLUTION: A thermoplastic resin film has a thermoplastic resin A having polyarylene sulfide as the main component, and a resin B different from the resin A; holes are included in a film; when a melting point or softening point of the resin A is Tma(°C) and a melting point or softening point of the resin B is Tmb(°C), the relationship Tmb>Tma is met; and an average dispersion diameter of the resin B in the film is 0.5-10.0 μm or less.SELECTED DRAWING: None

Description

The present invention relates to a thermoplastic resin film having excellent heat resistance, electrical properties, and processability.

Films and non-woven fabrics made of thermoplastic resins such as polyarylene sulfide, polyetherimide, polyethylene naphthalate, polyamide, polyetheretherketone, liquid crystal polymer, and fluororesin have heat resistance, electrical properties, low moisture absorption, and high temperature. Because of its excellent dimensional stability and chemical resistance, it is suitably used as an insulating material and a heat insulating material for electrical / electronic parts, battery parts, mechanical parts and automobile parts.
In recent years, the members to which these thermoplastic resin films have been applied have been miniaturized, and the thermoplastic resin films used in accordance therewith are required to maintain the same characteristics as the conventional thickness and to be thinned. There is.
When the thermoplastic resin film is thinned with the same composition, there is a problem that the mechanical properties and the electrical properties decrease as the thickness decreases (for example, Patent Documents 1 and 2).
Therefore, in order to maintain both the characteristics of the thermoplastic resin film, particularly the electrical characteristics and the thinning, a method of making the thermoplastic resin film porous has been proposed (for example, Patent Documents 4 and 5).

Japanese Unexamined Patent Publication No. 2008-266593 Japanese Unexamined Patent Publication No. 2011-127244 Japanese Unexamined Patent Publication No. 2013-206818 Japanese Unexamined Patent Publication No. 2014-102946

However, since the film to which the above method is applied contains a portion having a low resin density, there is a problem that the mechanical properties are significantly lowered and the workability is lowered.

An object of the present invention is to solve the above-mentioned problems. That is, it is to provide a thermoplastic resin film having excellent heat resistance, electrical characteristics, and processability (mechanical characteristics).

The thermoplastic resin film of the present invention has the following configuration in order to solve the above problems. That is,
It contains a thermoplastic resin A containing polyarylene sulfide as a main component and a resin B different from the resin, has pores in the film, and has a melting point or softening point of the resin A of Tma (° C.), which is a resin B. When the melting point or the softening point is Tmb (° C.), the relationship is Tmb> Tma, and the average dispersion diameter of the resin B in the film is 0.5 to 10.0 μm or less. It is a thermoplastic resin film.

The thermoplastic resin film of the present invention has excellent heat resistance, electrical properties, and workability, and is excellent in heat resistance, electrical characteristics, and workability, and is used for electrical / electronic equipment, battery parts, mechanical parts, automobile parts, insulating materials, printing equipment parts, heat-resistant tape, circuit boards, and mold release. It can be suitably used as a film.

The thermoplastic resin film of the present invention contains a thermoplastic resin A containing polyarylene sulfide as a main component. Here, the main component refers to a component that accounts for 60% by mass or more of the resin composition constituting the film. By containing the thermoplastic resin A containing polyarylene sulfide as a main component, excellent durability can be exhibited. The concentration of the thermoplastic resin A in the thermoplastic resin film is preferably 60 to 95% by mass, more preferably 60 to 85% by mass.

The polyarylene sulfide resin preferably used as the thermoplastic resin A of the present invention refers to a copolymer having a repeating unit of − (Ar—S) − (Ar represents an aryl group). Examples of Ar include units represented by the following formulas (A) to (K).

(In formulas (A) to (I), R1 and R2 are substituents selected from hydrogen, alkyl groups, alkoxy groups, and halogen groups, and R1 and R2 may be the same or different).
As the repeating unit, the p-allylen sulfide unit represented by the above formula (A) is preferable, and typical examples thereof include polyphenylene sulfide, polysulfone, polyether sulfone, polyphenylene sulfide sulfone, polyphenylene sulfide ketone and the like. As a particularly preferable p-allylen sulfide unit, a p-phenylene sulfide unit is preferably exemplified from the viewpoint of film physical properties and economic efficiency.

The polyarylene sulfide resin used as the thermoplastic resin A of the present invention comprises a p-phenylene sulfide unit represented by the following structural formula (1) as a main constituent unit in an amount of 80 mol% or more and 99.9 mol% or less of all repeating units. It is preferable that it is. With the above composition, excellent heat resistance and chemical resistance can be exhibited.

Further, it can be copolymerized with the copolymerization unit in the range of 0.01 mol% or more and 20 mol% or less of the repeating unit.

Preferred copolymerization units include the following structural formulas (2) to (6), and particularly preferable copolymerization units are m-phenylene sulfide units. The mode of copolymerization with the copolymerization component is not particularly limited as the main constituent unit, but a random copolymer is preferable.

(Here, X indicates alkylene, CO, SO ₂ units.)

(In formula (6), R represents an alkyl group, a nitro group, a phenylene group, and an alkoxy group.)
The thermoplastic resin film of the present invention contains a thermoplastic resin B different from the thermoplastic resin A. The thermoplastic resin B may be either crystalline or amorphous, and examples of the crystalline resin include a thermoplastic polyimide resin, an aromatic polyether ketone, an aromatic aryl ketone, and a liquid crystal polymer (LCP). As the amorphous resin, it is preferable to contain at least one selected from polyetherimide (PEI), thermoplastic polyamideimide resin and the like. Among them, it is preferable to contain at least one selected from any of liquid crystal polymer, polyetherimide, thermoplastic polyimide resin, and polyetheretherketone, and it is selected from any of crystalline thermoplastic polyimide resin and polyetheretherketone. It is particularly preferable to include at least one of the above-mentioned materials from the viewpoint of heat resistance, electrical characteristics, and processability.

When the melting point or softening point of the thermoplastic resin A used in the thermoplastic resin film of the present invention is Tma (° C.) and the melting point or softening point of the thermoplastic resin B is Tmb (° C.), there is a relationship of Tmb> Tma. 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. By having the above-mentioned relationship of thermal characteristics, the average dispersion diameter of the thermoplastic resin B can be controlled within the range described later when the thermoplastic resin film is formed, and excellent dimensional stability can be exhibited. ..

In the thermoplastic resin film of the present invention, the difference (Tmb-Tma) between the melting point or softening point (Tmb) of the thermoplastic resin B and the melting point or softening point (Tma) of the thermoplastic resin A is preferably 20 ° C. or higher. More preferably, it is above ° C. By having the above-mentioned relationship of thermal characteristics, when a thermoplastic resin film is formed, the width of the average dispersion diameter can be reduced when controlling the average dispersion diameter of the thermoplastic resin B to the range described later, or as a film. Dimensional stability can be improved.

The melting point of the thermoplastic resin used in the present invention can be evaluated by a differential scanning calorimeter, and the softening point can be evaluated by a method described later using a thermomechanical analyzer.

The concentration of the thermoplastic resin B contained in the thermoplastic resin film of the present invention is preferably 40% by mass or less, more preferably 5 to 40% by mass, and further preferably 15 to 40% by mass. preferable. By setting the above concentration, pores can be efficiently formed in the thermoplastic resin film. When the concentration of the thermoplastic resin B is less than 5% by mass, the interface between the thermoplastic resin B and the thermoplastic resin A, which is the starting point of the pores, is reduced, so that the pores are hard to be formed and the electrical characteristics of the thermoplastic resin film are deteriorated. May decrease. Further, if the concentration of the thermoplastic resin B exceeds 40% by mass, it becomes difficult to stretch the thermoplastic resin film during production, and the productivity may decrease. The concentration of the thermoplastic resin B can be evaluated by the method described later.

The thermoplastic resin film of the present invention preferably has pores formed around the thermoplastic resin B as a core. Further, it is more preferable that the interface between the thermoplastic resin B and the matrix thermoplastic resin A is clear. By having the above structure, it is possible to suppress excessive stress concentration around the domain of the thermoplastic tree B and efficiently form pores in the film necessary for lowering the relative permittivity. In order to form pores with the thermoplastic resin B as the central core, it can be achieved by setting the thermal characteristics of the thermoplastic resins A and B within the above-mentioned range. The presence or absence of nuclei of pores can be evaluated by observing the cross section with a scanning electron microscope SEM. The method for forming the pores with the thermoplastic resin B as the core is not particularly limited, but the manufacturing method described later is used using the thermoplastic resin A and the thermoplastic resin B having Tma and Tmb in the above-mentioned range. For example, forming a film with.

The average dispersion diameter of the thermoplastic resin B contained in the thermoplastic resin film of the present invention needs to be 0.5 to 10.0 μm, more preferably 0.5 to 5.0 μm. By setting the average dispersion diameter in the above range, excessive stress concentration of the thermoplastic tree B dispersed in the thermoplastic resin A around the domain is suppressed in the stretching step when the thermoplastic resin film is produced. , Pore in the film necessary for lowering the relative permittivity can be efficiently formed. If the average dispersion diameter is smaller than 0.5 μm, it becomes difficult for pores to be formed during stretching, so that the effect of reducing the relative permittivity may not be sufficiently obtained. Further, when the average dispersion diameter is 10.0 μm or more, stress concentration tends to occur around the thermoplastic tree B dispersed during the production of the film, which causes a decrease in productivity due to tearing and a decrease in mechanical properties as a film. , The processability may deteriorate when the film is processed into the final use form. The method for evaluating the average dispersion diameter of the thermoplastic resin B contained in the thermoplastic resin film can be confirmed by a method described later. The average dispersion diameter of the thermoplastic resin B can be controlled by the raw material manufacturing method and film forming conditions described later.

As a method for forming pores in the thermoplastic resin film of the present invention, since the process can be simplified and the productivity is excellent, the dry method (the resin is melted and extruded into a sheet is stretched to make it porous. Method) is preferably used.

The thermoplastic resin film of the present invention has pores in the film. The ratio of pores in the film (porosity) is preferably 20% or more. By having the above porosity, it is possible to improve the electrical characteristics of the thermoplastic resin film. Here, the porosity refers to the ratio of the area of the pores contained in the image when the cross-sectional area of the thermoplastic resin film of any size is 100, and the pores are formed in the cross-sectional image of the arbitrary size. If it is not observed, the porosity is 0%. When the porosity is smaller than 20%, the pores contained in the thermoplastic resin film are reduced, and the proportion of air having a small relative permittivity in the film is reduced, so that the electrical characteristics may be deteriorated. The higher the porosity, the more preferable, but from the viewpoint of maintaining productivity, 70% or less is preferable. The porosity is preferably 20-60% and 30-50%. The porosity can be set within the above range by controlling the concentration and dispersion diameter of the thermoplastic tree B contained in the thermoplastic resin film and applying the film forming conditions described later. The porosity can be confirmed by evaluating the cross section of the thermoplastic resin film by the method described later.

The aspect ratio of the domain of the thermoplastic resin B contained in the thermoplastic resin film of the present invention is preferably 1.1 to 4.0, more preferably 1.5 to 3.0. The aspect ratio of the domain of the thermoplastic resin B can be adjusted by controlling the temperature at the time of stretching the film within an appropriate range. By controlling the aspect ratio of the thermoplastic resin B, stress concentration during stretching on the surface of the domain can be suppressed, and the mechanical strength and porosity can be maintained within a certain range. If the aspect ratio is smaller than 1.5, the domain of the thermoplastic resin B is not deformed during stretching, and strain remains at the interface of the thermoplastic resin A, which is a matrix, and the mechanical properties of the thermoplastic resin film may deteriorate. .. Further, when the aspect ratio is larger than 4, the domain of the thermoplastic resin B is significantly deformed at the time of stretching, and sufficient porosity may not be formed at the time of stretching, and the porosity may decrease. The aspect ratio of the domain of the thermoplastic resin B contained in the thermoplastic resin film of the present invention can be evaluated by the method described later.

The thermoplastic resin film of the present invention may contain inorganic particles as a composition constituting the film. When using inorganic particles, oxide-based ceramics such as alumina, silica, titania, zirconia, magnesia, ceria, itria, zinc oxide, and iron oxide, nitride-based ceramics such as silicon nitride, titanium nitride, and boron nitride, silicon carbide, etc. Calcium carbonate, aluminum sulfate, barium sulfate, potassium titanate, talc, kaolin clay, kaolinite, halloysite, pyrophyllite, montmorillonite, cericite, mica, amesite, bentonite, asbestos, zeolite, calcium silicate, magnesium silicate , Ceramics such as kaolin, kaolin, and inorganic compounds such as glass fiber can be blended. Further, the inorganic particles used can be surface-treated within a range that does not impair the physical properties of the thermoplastic resin film. The inorganic particles used may be one kind, or a plurality of kinds may be mixed and used. Among the above, calcium carbonate, barium sulfate, zinc oxide and silica are preferable from the viewpoint of dispersibility, and calcium carbonate and silica are most preferable from the viewpoint of low cost.

When inorganic particles are used as the composition constituting the thermoplastic resin film of the present invention, the volume average particle diameter of the inorganic particles is preferably 0.3 to 10 μm, more preferably 0.5 to 5 μm. preferable. By using the particles having the above-mentioned volume average particle diameter, it is possible to suppress the aggregation of the particles and suppress the stress around the inorganic particles when they are stretched. If the volume average particle size of the inorganic particles is less than 0.3 μm, agglomeration of the particles is likely to occur and the stretchability may be lowered. Further, when the volume average particle diameter is larger than 10 μm, the difference from the dispersion diameter of the thermoplastic resin B contained in the film becomes large, stress tends to concentrate at the interface between the thermoplastic resin A and the inorganic particles, and the mechanical strength of the film increases. May decrease.

When inorganic particles are used as the composition constituting the thermoplastic resin film of the present invention, the blending concentration thereof is preferably 0.1 to 20% by mass, more preferably 0.1 to 10% by mass. By setting the concentration of the inorganic particles in the above range, pores can be efficiently formed in the film.

The thermoplastic resin film of the present invention may have a laminated structure of two or more layers. Selectable laminated configurations include two layers (I) / (II) composed of layers (I) and (II) of any formulation, (I) / (II) / (I), (II). Multi-layered configurations such as / (I) / (II), (II) / (I) / (II) / (I), (II) / (I) / (II) / (I) / (II) are listed. However, it is not limited to this. Further, a layer structure having a layer having a composition different from that of (I) to (II) can be further added.

The thickness of the thermoplastic resin film of the present invention is preferably 5 to 350 μm, more preferably 10 to 300 μm from the viewpoint of productivity. The film thickness and the layer thickness can be controlled by adjusting the supply amount of the raw material when obtaining the unstretched sheet. The film thickness and layer thickness can be evaluated by the method described later.

The thermoplastic resin film of the present invention preferably has a relative permittivity of 3.0 or less at a frequency of 10 GHz at a temperature of 23 ° C. and 65% RH, and more preferably 2.8 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. If the relative permittivity is larger than 3.0, the transmission loss may increase when used as a substrate material. The lower the relative permittivity, the more preferable, but the feasible range is 1.8 or more. The relative permittivity can be within the above range by setting the composition and properties of the thermoplastic resin film to the above-mentioned constitution. The relative permittivity can be evaluated by the method described later.

In the thermoplastic resin film of the present invention, the absolute value of the transmission loss at 10 to 40 GHz at 23 ° C. and 65% RH is preferably less than 30 dB / 100 mm, and more preferably less than 25 dB / 100 mm. The transmission loss represents the degree of deterioration of the signal flowing on the communication line. If the transmission loss is larger than 30 dB / 100 mm, the deterioration of the input signal on the circuit line is large, and it becomes difficult to apply it as a member of a device during large-capacity communication. The lower the absolute value of the transmission loss, the more preferable. The transmission loss can be within the above range by setting the thermoplastic resin film to the above-mentioned relative permittivity. The transmission loss can be evaluated by the method described later.

In the thermoplastic resin film of the present invention, it is preferable that the average value of the end crack resistance in an arbitrary direction and the direction perpendicular to the thermoplastic resin film in terms of 200 μm is 120 N / 20 mm or more. By having the above-mentioned characteristics, when the thermoplastic resin film is put into practical use, it is possible to exhibit durability against stress applied in the thickness direction of the thermoplastic resin film. If the end crack resistance is smaller than 120 N / 20 mm, tearing is likely to occur when stress is applied in the thickness direction, and it may not be practical. The higher the upper limit of the end crack resistance is, the more preferable it is, but the feasible range is 1500 N / 20 mm or less. The average value of the end crack resistance in an arbitrary direction and the direction orthogonal to it in terms of 200 μm is more preferably 130 N / 20 mm or more, and further preferably 150 N / 20 mm or more. The end crack resistance can be achieved in the above range by setting the composition, characteristics, and film forming conditions described above. The end crack resistance can be evaluated by the method described later.

The method for producing a thermoplastic resin film of the present invention will be described by taking as an example a case where a polyarylene sulfide resin is used.

A method for producing a polyarylene sulfide resin preferably used for the thermoplastic resin film of the present invention will be described. Sodium sulfide and p-dichlorobenzene are mixed and reacted in an amide-based polar solvent such as N-methyl-2-pyrrolidone (NMP) under high temperature and high pressure. If necessary, it is also possible to include a copolymerization component such as m-dichlorobenzene or trihalobenzene. Potassium hydroxide, an alkali metal carboxylic acid salt, or the like is added as a degree of polymerization adjusting agent, and the polymerization reaction is carried out at 230 to 290 ° C. After the polymerization, the polymer is cooled, and the polymer is filtered through a filter as an aqueous slurry to obtain a wet granular polymer. An amide-based polar solvent is added to this granular polymer, and the mixture is stirred and washed at a temperature of 30 to 100 ° C., washed several times with ion-exchanged water at 30 to 80 ° C., and several times with an aqueous metal salt solution such as calcium acetate. After washing, it is dried to obtain a granular polymer of a polyarylene sulfide resin which is a thermoplastic resin A. The thermoplastic resin A and a different thermoplastic resin B are blended at an arbitrary ratio as described above, put into an extruder with a vent set at 300 to 350 ° C., melt-extruded into a strand shape, and heated to a temperature of 25 ° C. After cooling with the water of the above, cutting is made to prepare a chip, which is used as a raw material for a film. At this time, the temperature (actual temperature) of the molten resin itself at the time of extrusion is set to the melting point or softening point Tmb to (Tmb + 20) ° C. of the thermoplastic resin B, so that the average dispersion diameter can be within the above range. If it is lower than the above resin temperature, the thermoplastic resin B may not be sufficiently melted at the time of dispersion, and the dispersion diameter may become large and control may not be possible. Further, when the temperature exceeds the above temperature, the melt viscosity of the thermoplastic resin B becomes small and the dispersion diameter becomes small, or the thermoplastic resin B undergoes thermal deterioration during extrusion and the mechanical properties deteriorate when the film is formed. There is. The actual temperature of the molten resin can be measured by using an infrared radiation thermometer (AD-5614, manufactured by A & D Co., Ltd.) immediately after being discharged from the die head at the time of extrusion. When the thermoplastic resins A and B are melt-extruded, inorganic particles, additives and the like can be blended in an arbitrary ratio. After the raw material for a film is dried under reduced pressure at 180 ° C. for 3 hours, a full-flight single shaft whose molten portion is set between the melting point or softening point Tma of the thermoplastic resin A and the melting point or softening point Tmb of the thermoplastic resin B. After being supplied to an extruder and passed through a filter, it is discharged from a T-die type base, and is brought into close contact with a cooling drum having a surface temperature of 20 to 70 ° C. while applying an electrostatic charge to quench and solidify, and is substantially non-oriented. An unstretched film in the state is obtained.

Next, in the case of biaxial stretching, the stretching method includes a sequential biaxial stretching method (a stretching method that combines stretching in each direction such as a method of stretching in the longitudinal direction and then stretching in the width direction), and simultaneous biaxial stretching. A stretching method (a method of stretching in the longitudinal direction and the width direction at the same time) or a method in which they are combined can be used. Here, a sequential biaxial stretching method in which stretching is performed first in the longitudinal direction and then in the width direction will be illustrated.

The unstretched film obtained above is heated with a heating roll group, and the unstretched film is heated 2.8 to 5.0 times in the longitudinal direction (MD direction), more preferably 2.8 to 4.5 times. Stretching in stages or in multiple stages of two or more stages (MD stretching). The stretching temperature is in the range of the glass transition temperature (Tg) to the cold crystallization temperature (Tcc) of the thermoplastic resin A, preferably (Tg + 5) to (Tcc-10) ° C. Then, 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. 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 of the thermoplastic resin A, more preferably in the range of (Tg + 5) to (Tcc-10) ° C. The draw ratio is preferably 2.8 to 5.0 times, preferably 2.8 to 4.5 times, from the viewpoint of the flatness of the film.

At this time, regarding the stretch ratio of the film, the ratio of the MD ratio to the TD ratio (stretch ratio = MD ratio / TD ratio) is preferably 1.05 or less, more preferably 1.00 or less, and 0.95 or less. More preferred. When the pores contained in the layer (I) are stretched in the MD direction, which is the initial stretching direction, stress is concentrated at the interface between the resin and the particles, and peeling occurs. After that, a hole extending in the MD direction is formed starting from this peeling point. At this time, heat is generated at the particle / resin interface due to stress concentration, and when a crystalline thermoplastic resin is used as the resin composition of the film, local crystallization progresses, and the plasticity of the resin part due to heating during stretching progresses. It is thought that it interferes with deformation and forms minute pores that form pores, causing brittleness. Further, it is considered that the amorphous resin softens the resin too much, causing poor formation of pores. Therefore, if excessive stretching in the MD direction is performed, the crystalline thermoplastic resin is likely to be stretched and broken due to the subsequent stretching in the TD direction, and a decrease in the mechanical strength of the film becomes apparent. .. Further, in the case of amorphous resin, the porosity may be low even though it is stretched biaxially. Therefore, the draw ratio in the MD direction is preferably low as long as the flatness is not impaired, and the draw ratio in the TD direction should be high as long as the film does not tear, which is the mechanical characteristics after biaxial stretching, especially the end crack resistance. It is important to maintain the balance of electrical characteristics.

Next, an operation (heat fixing process) of heat-fixing the stretched film under tension is performed. The temperature of the heat treatment zone is the whole of the heat treatment zone, and either the heat treatment is performed at the same temperature, or the heat treatment is performed at different temperatures in the first half and the second half of the heat treatment zone. .. The heat fixing temperature is preferably 160 ° C. to the melting point or softening point (Tma) of the thermoplastic resin A, and preferably 180 to (Tma-10) ° C. from the viewpoint of suppressing heat shrinkage as a film. After the heat-fixing treatment, the film is cooled to a room temperature, and if necessary, relaxed by 1 to 20% in the longitudinal and width directions, and then wound to obtain a biaxially stretched thermoplastic resin film.

The thermoplastic resin film of the present invention has excellent heat resistance, electrical properties, and workability, and is excellent in heat resistance, electrical characteristics, and workability, and is used for electrical / electronic equipment, battery parts, mechanical parts, automobile parts, insulating materials, printing equipment parts, heat-resistant tape, circuit boards, and mold release. It can be suitably used as a film.

[Measurement method of characteristics]
(1) Melting point or softening point of the thermoplastic resin film a. Melting point (℃)
When using crystalline resin as resin A and resin B of the thermoplastic resin film, according to JIS K7121-1987, DSC (RDC220) manufactured by Seiko Instruments Co., Ltd. is used as the differential scanning calorimeter, and disk station manufactured by Seiko Instruments Co., Ltd. is used as the data analysis device. Using SSC / 5200), the weighed 3 mg sample was heated from room temperature to 340 ° C. at a heating rate of 20 ° C./min on an aluminum saucer, and the peak temperature of the endothermic peak of melting observed at that time was measured. Measure. The measurement was carried out three times per sample, and the average value of the obtained values was taken as the melting point (° C.) of the sample.

b. Softening point (℃)
When an amorphous resin is used as the resin A and the resin B of the thermoplastic resin film, it is cut into a circle having a diameter of 5 mm and used as a sample. This sample was heated in a thermomechanical analyzer (SS6100, manufactured by Hitachi High-Tech Science Co., Ltd.) using a conical needle-inserted probe with a tip diameter of 0.5 mm under a load of 49 mN under a heating condition of 10 ° C./min. The softening point is measured from the plot of the needle insertion amount of the probe and the heating temperature. The measurement was carried out three times per sample, and the average value of the obtained values was taken as the softening point (° C.) of the sample.

(2) Thickness of thermoplastic resin film, average dispersion diameter / aspect ratio of thermoplastic resin B, concentration of thermoplastic resin B Cross section of a sample fixed on a sample table of a scanning electron microscope with the thickness direction as the normal direction. After cutting the cross section by ion etching for 10 minutes under the conditions of decompression degree 10 ^-3 Torr, voltage 0.25 KV, current 12.5 mA using a sputtering device, the surface is cut with the same device. Is sputtered with gold, and a scanning electron microscope SEM (JSM6700F manufactured by JEOL Ltd.) is used to take a cross-sectional photograph of 2,000 times the above sample.

a. The thickness of the thermoplastic resin film was measured from the image obtained by the thickness observation. If the entire thickness direction of the thermoplastic resin film cannot be confirmed at the above magnification, several images are taken in the thickness direction, and the entire image is confirmed by stitching the images together. A total of 10 samples were selected at arbitrary locations for measuring the thickness, and the average of the measured values of the 10 samples was taken as the film thickness of the sample.

b. An image analysis software (MacView ver4.0, manufactured by Mountech Co., Ltd.) was used to create a cross-sectional projection image of the obtained cross-sectional photograph of the average dispersion diameter of the thermoplastic resin B. After measuring the diameter of the minimum circumscribed circle for all the domains of the thermoplastic resin B included in the cross-sectional projected image, the average value (R) was calculated. The evaluation was performed at 5 locations in each of the arbitrary direction of the film and the direction perpendicular to it, and the average value of (R) obtained from the evaluation of a total of 10 points was the average of the thermoplastic resin B contained in the sample. The dispersion diameter was used.

c. For the cross-sectional photograph obtained with the aspect ratio of the thermoplastic resin B, a cross-sectional projection image is created using image analysis software (MacView ver4.0, manufactured by Mountech Co., Ltd.), and is included in the cross-sectional projection image using the same software. The aspect ratios were calculated for all the domains of the thermoplastic resin B, and the average value was used as the aspect ratio of the domains of the thermoplastic resin B contained in the sample.

(3) Concentration of thermoplastic resins A and B in the film 0.1 g of the thermoplastic resin film was weighed, sandwiched between SUS plates, and heated to a melting point equal to or higher than the thermoplastic resin A measured in (1) on a hot stage. After that, it is rapidly cooled to eliminate the pores contained in the film. Next, the rapidly cooled film-like sample was fixed on the sample table of the scanning electron microscope, and the degree of decompression was ^10-3 Torr and the voltage was 0.25 KV using a sputtering device so that the cross section with the thickness direction as the normal direction could be seen. After cutting the cross section by ion etching for 10 minutes under the condition of a current of 12.5 mA, the surface was subjected to gold sputtering by the same apparatus, and using a scanning electron microscope SEM, the above sample 2, Take a 000x cross-sectional photograph.
For the obtained cross-sectional photograph, a cross-sectional projection image was created using image analysis software (MacView ver4.0, manufactured by Mountech Co., Ltd.), and all the domains of the thermoplastic resin B contained in the cross-sectional projection image were created using the software. And the total area of the film portion in the cross-sectional projected image were calculated and used as the concentrations (% by mass) of the thermoplastic resin B and the thermoplastic resin A using the following formula.
Concentration of thermoplastic resin B (mass%) = [Area of thermoplastic resin B / total area of film portion in cross-sectional projected image] × 100
Concentration of thermoplastic resin A (% by mass) = 100-Concentration of thermoplastic resin B (% by mass).

(4) Porosity (%)
The sample fixed on the sample table of the scanning electron microscope was subjected to the conditions of decompression degree 10 ^-3 Torr, voltage 0.25 KV, current 12.5 mA using a sputtering device so that the cross section perpendicular to the surface of the film could be seen. After 10 minutes of ion etching treatment to cut the cross section, the surface was subjected to gold sputtering by the same apparatus and observed at a magnification of 2000 times using a scanning electron microscope. For the obtained observation image, image analysis software (MacView ver4.0, manufactured by Mountech Co., Ltd.) was used to determine the area A (μm ² ) of the pores and the total area B (μm ² ) of the observation image. The porosity C (%) was calculated and applied to the following formula. Evaluation was performed at 5 locations in each of the two directions of the film in any direction and in the direction perpendicular to it, a total of 10 observation images were taken and the porosity was calculated, and the average of the 10 points was the porosity (the porosity). %).
Porosity C (%) = area A (μm ² ) of the hole portion / total area B (μm ² ) × 100.

(5) Relative Permittivity The relative permittivity is measured by the cavity resonator perturbation method at a frequency of 10 GHz using a dielectric material measuring device (manufactured by Kanto Denshi Applied Development Co., Ltd.). A sample cut out to 2.7 mm × 45 mm in an arbitrary direction was inserted into the cavity resonator, and measurement was performed in a temperature of 23 ° C. and a humidity of 65% RH. The measurement was performed with n = 3, and the average value of the obtained values was obtained.

(6) 200 μm equivalent end crack resistance (N / 20 mm)
Evaluation is performed according to JISC2151 (1990). After sampling the sample to a width of 20 mm and a length of 300 mm, use an electronic micrometer (manufactured by Anritsu Co., Ltd., K-312A type, stylus pressure 30 g) in an atmosphere of 23 ° C. and 65% RH at any three locations of the sample. The thickness was measured, and the average value was taken as the sample thickness (μm). Next, the measurement was carried out using the test fitting B (V-shaped notch type) under the conditions of a tensile speed of 200 mm / min and 23 ° C. Since the end crack resistance is proportional to the thickness, the measured value and the thickness were inserted into the following formula to obtain the end crack resistance in terms of 200 μm.
End crack resistance (N / 20 mm) converted to 200 μm = measured value of each sample (N / 20 mm) / thickness (μm) x 200 (μm)
The measurement was carried out for 10 films each in an arbitrary direction of the film and in a direction perpendicular to the film, and the numerical value obtained by the arithmetic mean was taken as the end crack resistance (N / 20 mm) of the sample in terms of 200 μm.

(7) Transmission characteristics (electrical characteristics)
After applying the circuit board adhesive AW-32 (manufactured by Kyodo Yakuhin Co., Ltd.) to both surfaces of the thermoplastic resin film with a solidified thickness of 2 μm, a 12 μm copper foil (3EC-HTE, manufactured by Mitsui Metal Industry Co., Ltd.) Was pressed on both surfaces by pressing at a pressure of 4 MPa for 10 minutes with a vacuum heat press device heated to 170 ° C. to prepare a laminate having a structure 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 leaving the above sample in a temperature of 23 ° C. and a humidity of 65% RH for 24 hours, a network analyzer (“8722ES” manufactured by Agilent Technologies) and a probe (ACP40-250) manufactured by Cascade Microtech were used at 10-40 GHz. 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 25 dB / 100 mm B: Absolute value of transmission loss is 25 dB / 100 mm or more and less than 30 dB / 100 mm C: Absolute value of transmission loss is 30 dB / 100 mm or more.

(8) Workability Using a motor slot processing machine (manufactured by Odawara Engineering Co., Ltd.), the sample is processed into a slot shape with a width of 20 mm and a length of 40 mm at a processing speed of 2 months / sec, and the processed sample is visually confirmed. , Samples that were deformed or torn were regarded as defective products, and the defective product occurrence rate was evaluated according to the following criteria. The number of processed samples is 100 for each sample.
AA: Defect rate is less than 15% A: Defect rate is 15% or more and less than 25% B: Defect rate is 25% or more and less than 40% C: Defect rate is 40% or more.

(9) A heat-resistant thermoplastic resin film was cut into a test piece having a width of 10 mm and a length of 250 mm in an arbitrary direction of the film and in a direction perpendicular to the film, and in a hot air oven set at a temperature of 200 ° C. for 1000 hours. The heat treatment was performed, the elongation at break before and after the heat treatment was measured, the elongation retention rate was calculated from the following formula, and evaluated according to the following criteria. For the elongation at break, a sample piece having a width of 10 mm is set to have a chuck-to-chuck length of 100 mm using a Tensilon tensile tester according to the method specified in JIS-C2151, and a tensile test is performed at a tensile speed of 300 mm / min. .. The evaluation was performed 10 times in each direction, the average value was calculated, and the evaluation was performed according to the following criteria.

Elongation retention rate (%) = Y / Y0 × 100
Y0: Elongation at break (%) before heat treatment
Y: Elongation at break (%) after heat treatment
A: Elongation retention rate is 80% or more B: Elongation retention rate is 50% or more and less than 80% C: Elongation retention rate is less than 50%.

(10) Presence or absence of nuclei of pores For a cross section of the thermoplastic resin film whose thickness direction is the normal direction in any direction from any place, a decompression degree 10 ^-3 Torr, voltage 0.25 KV, using a sputtering device. After performing ion etching treatment for 10 minutes under the condition of a current of 12.5 mA to cut a cross section, the surface is subjected to gold sputtering by the same apparatus, and a scanning electron microscope SEM (manufactured by JEOL Ltd., JSM6700F) A 3,000-fold cross-sectional photograph of the above sample was taken using the above sample to determine the presence or absence of the thermoplastic resin B domain inside the pores or at a part of the boundary between the thermoplastic resin A forming the matrix and the pores. It was confirmed and evaluated according to the following criteria.
A: The domain of the thermoplastic resin B can be confirmed inside the pores or a part of the boundary between the thermoplastic resin A and the pores, and the interface between the thermoplastic resin A and the thermoplastic resin B can be clearly observed.
B: The domain of the thermoplastic resin B can be confirmed inside the pores or in a part of the boundary between the thermoplastic resin A and the pores.
C: The domain of the thermoplastic resin B cannot be confirmed inside the pores or in a part of the boundary between the thermoplastic resin A and the pores.

(11) Dimensional stability A strip piece having a length of 40 mm and a width of 4 mm is collected from an arbitrary portion of the thermoplastic resin film in an arbitrary direction. In addition, samples of the same size are taken in the direction orthogonal to the film plane direction. A heat shrinkage curve was obtained when these samples were heated to 25 to 250 ° C. with a thermomechanical analyzer (TMA-50, manufactured by Shimadzu Corporation) under the conditions of a trial length of 15 mm, a load of 0.5 g, and 10 ° C./min. .. The temperature at which the displacement amount obtained from this heat shrinkage curve shrinks by 10% with respect to the initial value was obtained. The evaluation was performed at n = 5 in each of the arbitrary direction and the direction orthogonal to it, and the average value of 10 points was evaluated as the dimensional stability of the sample according to the following criteria.
A: 10% shrinkage temperature is 200 ° C or higher B: 10% shrinkage temperature is 150 ° C or higher and less than 200 ° C C: 10% shrinkage temperature is less than 150 ° C.

(Reference Example 1) Method for producing polyphenylene sulfide resin (granule) 100 mol of sodium sulfide 9 hydroxide, 45 mol of sodium acetate and 25 liters of N-methyl-2-pyrrolidone in an autoclave (maximum working pressure: 14 MPa). (Hereinafter, abbreviated as NMP) was charged, and the temperature was gradually raised to 220 ° C. with stirring, and the contained water was removed by distillation. In the dehydrated system, 100 mol of p-dichlorobenzene as the main component monomer was added together with 5 liters of NMP, nitrogen was pressurized and sealed at a temperature of 170 ° C. at 3 kg / cm ² , and then the temperature was raised to 270. Polymerization was carried out at a temperature of ° C. for 4 hours. After completion of the polymerization, the polymer was cooled, the polymer was precipitated in distilled water, and a small mass polymer was collected by a wire mesh having a 150 mesh mesh. The small lump polymer thus obtained was washed twice with distilled water at 90 ° C., washed three times with an aqueous sodium acetate solution, washed once with distilled water, and dried at a temperature of 120 ° C. under reduced pressure. Then, granules (PPS) of polyphenylene sulfide resin having a melting point of 280 ° C. were obtained.

(Examples 1 to 3)
The PPS of Reference Example 1 and the PEEK resin having a melting point of 345 ° C. (Kitaspire 820NT, manufactured by Solay) were weighed at the ratios shown in Table 1, and were heated to 350 ° C. in the same direction rotary twin-screw kneading extruder with a vent. Made by Japan Steel Works, screw diameter 30 mm, screw length / screw diameter = 45.5), and discharged in a strand shape while adjusting the rotation speed and feed amount so that the resin temperature becomes 360 ° C, and the temperature is 25. After cooling with water at ℃, it was immediately cut to prepare a chip, which was used as a raw material for a film. This raw material is vacuum-dried at 180 ° C. for 3 hours, then supplied to an extruder heated to 320 ° C., passed through a 55 μm-cut sintered filter in a molten state, and then discharged from a T-die type base to surface. An unstretched sheet having a temperature of 250 μm was obtained by close contact and quenching and solidification while applying a static charge to a cast drum having a temperature of 25 ° C. Next, the obtained unstretched sheet was preheated with a plurality of heating rolls heated to a surface temperature of 90 ° C., and then the heating roll heated to a surface temperature of 100 ° C. and the peripheral speed provided next to the heating rolls. It was stretched 3.5 times in the longitudinal direction (MD direction) with different cooling rolls at 30 ° C. The uniaxially stretched sheet thus obtained was stretched 3.5 times at a temperature of 95 ° C. in the longitudinal direction and the vertical direction (TD direction) using a tenter, and then heat-treated at 260 ° C. and continued at 260 ° C. After performing a relaxation treatment of 5% in the TD direction in the relaxation treatment zone of No. 1, the film was cooled to room temperature to obtain a thermoplastic resin film having a thickness of 20 μm.

(Example 4)
The PPS of Reference Example 1 and the polyetherimide (PEI) resin (ULTEM1010, manufactured by SAVIC Innovative Plastics) having a softening point of 340 ° C. were weighed at the ratios shown in Table 1, and rotated in the same direction with a vent heated to 350 ° C. It is put into a type twin-screw kneading extruder (manufactured by Japan Steel Works, screw diameter 30 mm, screw length / screw diameter = 45.5), and strands are adjusted while adjusting the rotation speed and feed amount so that the resin temperature becomes 350 ° C. After being discharged into a shape and cooled with water having a temperature of 25 ° C., it was immediately cut to prepare a chip, which was used as a raw material for a film. A film was produced in the same manner as in Example 2 except that the above raw materials were used, to obtain a thermoplastic resin film having a thickness of 20 μm.

(Example 5)
The PPS of Reference Example 1 and the thermoplastic polyimide (PI) resin (Surprim, manufactured by Mitsubishi Gas Co., Ltd.) having a melting point of 320 ° C. are weighed at the ratios shown in Table 1, and are heated to 330 ° C. It is put into a kneading extruder (manufactured by Japan Steel Works, screw diameter 30 mm, screw length / screw diameter = 45.5) and discharged in a strand shape while adjusting the rotation speed and feed amount so that the resin temperature becomes 335 ° C. Then, after cooling with water at a temperature of 25 ° C., cutting was performed immediately to prepare a chip, which was used as a raw material for a film. A film was produced in the same manner as in Example 2 except that the above raw materials were used, to obtain a thermoplastic resin film having a thickness of 20 μm.

(Example 6)
The PPS of Reference Example 1 and the thermoplastic liquid crystal polymer (LCP) resin (Ciberus LX70, manufactured by Toray Industries, Inc.) having a melting point of 315 ° C. were weighed at the ratios shown in Table 1, and rotated in the same direction with a vent heated to 325 ° C. It is put into a type twin-screw kneading extruder (manufactured by Japan Steel Works, screw diameter 30 mm, screw length / screw diameter = 45.5), and strands are adjusted while adjusting the rotation speed and feed amount so that the resin temperature becomes 330 ° C. After being discharged into a shape and cooled with water having a temperature of 25 ° C., it was immediately cut to prepare a chip, which was used as a raw material for a film. A film was produced in the same manner as in Example 2 except that the above raw materials were used, to obtain a thermoplastic resin film having a thickness of 20 μm.

(Comparative Example 1)
0.03 parts by mass of manganese acetate tetrahydrate salt was added to a mixture of 100 parts by mass of dimethyl 2,6-naphthalenedicarboxylic acid and 60 parts by mass of ethylene glycol, and gradually increased from a temperature of 150 ° C to a temperature of 240 ° C. The transesterification reaction was carried out while raising the temperature. On the way, when the reaction temperature reached 170 ° C., 0.024 parts by mass of antimony trioxide was added. Further, when the reaction temperature reached 220 ° C., 0.042 parts by mass (corresponding to 2 mmol%) of tetrabutylphosphonium salt of 3,5-dicarboxybenzenesulfonic acid was added. Then, the transesterification reaction was subsequently carried out, and after the transesterification reaction was completed, 0.023 parts by mass of trimethyl phosphate was added. Next, the reaction product was transferred to a polymerization reactor, heated to a temperature of 290 ° C., and subjected to a polycondensation reaction under a high 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. -2,6-Naphthalate (PEN) chips were obtained. This chip and PEEK resin with a melting point of 345 ° C (Kitaspire 820NT, manufactured by Solay) were weighed at the ratios shown in Table 1, and were heated to 350 ° C. Manufactured by Japan Steel Works, screw diameter 30 mm, screw length / screw diameter = 45.5), and discharged in a strand shape while adjusting the rotation speed and feed amount so that the resin temperature becomes 360 ° C. Immediately after cooling with water, cutting was performed to prepare a chip, which was used as a raw material for a film. This raw material is vacuum-dried at 160 ° C. for 3 hours, then supplied to an extruder heated to 290 ° C., passed through a 55 μm-cut sintered filter in a molten state, and then discharged from a T-die type base to surface. An unstretched sheet of 350 μm was obtained in the same manner as in Example 2 except that the above raw materials were used by close contact and quenching and solidification while applying a static charge to a cast drum having a temperature of 25 ° C. Next, the obtained unstretched sheet was cut into a size of 100 mm × 100 mm, and preheated and stretched at 130 ° C. for 1 minute using a film stretcher (KARO-IV manufactured by Brookner). At a stretching speed of 5% / sec, the sheet was sequentially stretched at a stretching ratio of 3.5 times in the longitudinal (MD) direction and then 3.5 times in the lateral (TD) direction of the sheet, followed by heat treatment at 230 ° C. After that, it was cooled to room temperature to obtain a thermoplastic resin film having a thickness of 20 μm.

(Comparative Example 2)
The PPS of Reference Example 1 and then the PEEK resin having a melting point of 345 ° C. (Kitaspire 820NT, manufactured by Solay) were weighed at the ratios shown in Table 1 and heated to 370 ° C. in the same direction rotary biaxial kneading with a vent. It is put into an extruder (manufactured by Japan Steel Works, screw diameter 30 mm, screw length / screw diameter = 45.5) and discharged in a strand shape while adjusting the rotation speed and feed amount so that the resin temperature becomes 380 ° C. After cooling with water at a temperature of 25 ° C., cutting was immediately performed to prepare a chip, which was used as a raw material for a film. A film was produced in the same manner as in Example 2 except that the above raw materials were used, to obtain a thermoplastic resin film having a thickness of 20 μm.

(Comparative Example 3)
The PPS of Reference Example 1 and the PEN of Comparative Example 1 were weighed at the ratios shown in Table 1, and the same-direction rotary twin-screw kneading extruder with a vent heated to 290 ° C. (manufactured by Japan Steel Works, screw diameter 30 mm, screw) Put it in the length / screw diameter = 45.5), discharge it in a strand shape while adjusting the rotation speed and feed amount so that the resin temperature becomes 300 ° C, cool it with water at a temperature of 25 ° C, and then immediately cut it. A chip was produced and used as a raw material for a film. A film was produced in the same manner as in Example 2 except that the above raw materials were used, to obtain a thermoplastic resin film having a thickness of 20 μm.

The thermoplastic resin film of the present invention has excellent heat resistance, electrical properties, and workability, and is used for electrical / electronic equipment, battery parts, mechanical parts, automobile parts, insulating materials, printing equipment parts, heat-resistant tapes, circuit boards, and release materials. It can be suitably used as a mold film.

Claims (7)

The resin A contains a thermoplastic resin A containing polyarylene sulfide as a main component and a thermoplastic resin B (resin B) different from the thermoplastic resin A (resin A), and has pores in the film. When the melting point or softening point of the resin B is Tma (° C.) and Tmb (° C.), there is a relationship of Tmb> Tma, and the average dispersion diameter of the resin B in the film is 0.5 to 10.0 μm or less. A thermoplastic resin film characterized by being. The thermoplastic resin film according to claim 1, wherein the concentration of the thermoplastic resin A in the thermoplastic resin film is 60 to 95% by mass, and the concentration of the thermoplastic resin B is 5 to 40% by mass. The thermoplastic resin film according to claim 1, wherein the thermoplastic resin B contains at least one of an aromatic aryl ketone and a thermoplastic polyimide. The thermoplastic resin film according to claim 1, wherein Tmb-Tma ≥ 20 ° C. The thermoplastic resin film according to claim 1, wherein the aspect ratio of the domain of the thermoplastic resin B in the cross section perpendicular to the surface of the film is 1.1 to 4.0. The method for producing a thermoplastic resin film according to claim 1, wherein the melting and heating temperature at the time of sheeting or filming is lower than the melting point or softening point of the thermoplastic resin B. An insulating material using the thermoplastic resin film according to any one of claims 1 to 5.