JPH0939072A - Thermoplastic resin film and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To flatten a filter having a filler added thereto by passing a molten thermoplastic resin containing a filler specified in the standard deviation of a particle size through a filter specified the filler, filtering accuracy, the product of the diameter and basis wt. of metal fibers, the axial orientation of metal fibers, the voids of the filler and the flow resistance of air. SOLUTION: A thermoplastic resin containing a filler wherein an average particle size is δ and the standard deviation thereof is 0.1 δ or more is melted using an extruder. This resin is passed through a filter wherein the filler and filtering accuracy satisfy formula I, the product of the diameter (d) and wt. basis (w) of metal fibers of the n-th layer satisfy formulae II, III, media composed of metal fibers of which the axes are oriented in the direction crossing the flow of the molten resin at a right angle and having voids of 35-90% are laminated and the flow resistance of air is 35mm H2 O or more to be filtered and subsequently emitted from a cap to be quenched to be molded into a sheet form. n is the number from the upstream side of the media constituting the filter.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a thermoplastic resin film and a thermoplastic resin film produced by the method. More specifically, we manufacture thermoplastic resin films with less coarse protrusions used in base films for magnetic tape than thermoplastic resins with fillers and thermoplastic resin films with improved electrical properties used in dielectrics for capacitors. And a film therefor.

[0002]

2. Description of the Related Art Among thermoplastic resin films, polyethylene terephthalate, polyethylene 2, which are highly functional in mechanical properties, thermal properties, and electrical properties, among others.
Films based on 6-naphthalate, polyphenylene sulfide, polypropylene, polystyrene, polyamide, aramid, etc. are preferably used for magnetic materials, capacitors, electrical insulation, thermal transfer ribbons, stencil printing applications and the like.

These thermoplastic resin films are generally manufactured in a wide width, wound into a roll, and processed by a method such as coating, printing, vapor deposition and sputtering. It is an important quality characteristic that these thermoplastic resin films have good processability in these processing steps as well as the characteristics of the final product. In recent years, attempts have been made to improve the slipperiness and improve the workability and wear resistance by adjusting the surface roughness of the thermoplastic resin film by adding an appropriate filler in recent years, and the surface of the thermoplastic resin film has been improved. In order to meet the requirements for flatness and smoothness and the requirements for good slipperiness and wear resistance, special attention is paid to the material of the filler to be added, the state of forming fine particles, the size, and the amount added (for example, JP-A-6-322243, etc.). In addition, various methods for improving the dispersed state of these fillers at the thermoplastic resin production stage have been proposed (for example, JP-A-2-11636 and JP-A-6-322242).
Issue Bulletin). In particular, the flatness of the film surface as well as the smoothness are strongly required for magnetic material applications, capacitor applications, etc., and there is a great interest in selection in consideration of the characteristics of these fillers themselves.

[0004]

In view of the above problems, the present inventors have proposed a method in which the addition of an inorganic and / or organic filler to a thermoplastic resin does not impair the film quality such as flatness and smoothness. The present invention has been achieved as a result of intensive research.

Processability, that is, the quality represented by the surface roughness and slipperiness of the thermoplastic resin film, and the required quality of the final product, that is, the flatness, smoothness, abrasion resistance, and electrical characteristics of the thermoplastic resin film. The quality represented by (1) depends on the characteristics of the filler added together. In particular, the average particle size may be used as an index representing these characteristics.

In view of the relationship between the quality of these thermoplastic resin films and the particle size of the filler, the present inventors note that the particle size slightly larger than the average particle size of the added filler determines these qualities. The present invention has been reached.
Needless to say, the particle size distribution and the average particle size that determine the quality are obtained by controlling the particle size distribution in the filler manufacturing stage and / or the thermoplastic resin manufacturing stage to distribute the particle size distribution in the narrowest possible range. It is possible to match the diameters, but even if the particles adjusted in this way are used, when they are melted again using the extruder for film formation, they are re-aggregated and the desired flat, smooth heat is obtained. It may be difficult to obtain the surface of the plastic resin film.

An object of the present invention is to relatively easily obtain a desired film quality by physically cutting a filler coarser than the average particle diameter of the filler added to the thermoplastic resin.

Another object of the present invention is to prevent the appearance of large protrusions due to the agglomeration of the filler by dispersing the filler which is re-aggregated after being melted in the extruder.

Another object of the present invention is to provide a filter having an improved filtering ability as compared with a conventional filter which removes gels, foreign matters and the like in order to cut coarse particles of the filler.

Another object of the present invention is to provide a base film for magnetic materials having few coarse protrusions, a base film for capacitors having improved electric characteristics, and the like.

[0011]

In order to solve the above-mentioned problems, the method for producing a thermoplastic resin film of the present invention comprises an inorganic material having an average particle size δ and a standard deviation σ of 0.1 δ or more, and / or A thermoplastic resin containing one or more organic fillers is melted using an extruder, and the molten thermoplastic resin is filled with the filler and the filtration accuracy η satisfies the expression (1), and the diameter d of the metal fiber of the nth layer is d. The product (w · d) _{n of} and the basis weight w satisfies the equations (2) and (3), and the porosity is such that the axis of the metal fiber is arranged in the direction orthogonal to the flow of the molten thermoplastic resin. A method of laminating 35 to 90% of media, filtering through a filter having a flow resistance r by air of 35 mmH ₂ O or more, and then discharging from a die and rapidly cooling to form a sheet. Consists of. 2.5 <η / δ <50 (1) 400 <(wd) _n <16000 (2) (wd) _{n + 1} / (wd) _n ≤2.5 (3) (where (n is the number from the upstream side of the media that constitutes the filter)

This filter uses a filter made of media obtained by sintering metal fibers. The metal fiber is preferably made of stainless metal. The melt viscosity of the thermoplastic resin when passing through the filter is 20
Adjust to 0 to 12000 poise.

Further, the average particle size δ is 0.01 to 1.0.
The center line average roughness Ra of the film surface using a thermoplastic resin containing one or more fillers having a standard deviation σ of 0.1 δ or more in μm is 15 nm or less, and coarse protrusions of H2 or more are 5 or less.
It is possible to produce a base film for magnetic materials having a number of particles / 100 cm ² or less, and a primary particle diameter of 0.01 to 100 cm ^2.
Center line average roughness Ra and 10 of the film surface using a thermoplastic resin containing at least one aggregating filler having an average particle size δ of 0.2 μm to 3.0 μm and a standard deviation σ of 0.2δ or more. The point average roughness Rz and the maximum roughness Rmax satisfy Rmax ≦ (2δ) ^1/3 Rz Rz ≦ 10δ ^1/2 Ra, and a base film for a capacitor having Ra of 10 to 200 nm can be manufactured. .

The most preferable example of these thermoplastic resin films is a thermoplastic resin film having a thickness of 0.5 to 25 μm, such as polyethylene terephthalate or polyethylene 2,6-naphthalate, which is biaxially stretched and then heat set. is there.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below along with preferred embodiments. The thermoplastic resin used in the present invention is a highly functional thermoplastic resin such as polyethylene terephthalate, polyethylene 2,6-naphthalate, polyphenylene sulfide, polypropylene, polystyrene, which has high functionality in mechanical properties, thermal properties, and electrical properties. , Polyamide, aramid and the like are preferable. The present invention
In particular, a thermoplastic resin is melt extruded into a sheet, then biaxially stretched in the longitudinal and transverse directions, and heat-treated for magnetic materials, capacitors, electrical insulation, and thermal transfer ribbons that have excellent dimensional stability and mechanical and thermal stability. It is suitable for a thermoplastic resin film used for applications, stencil printing, etc.

In the present invention, an inorganic and / or organic filler is used in order to improve the final quality and handleability. The term “final” as used herein refers to the quality in the form of functioning as a product. In other words, in the case of magnetic material applications, the recorded or recorded material is reproduced more faithfully, and the flatness required for the base film, the formation of uniform protrusions, the limitation of coarse protrusions, and heat -It refers to all quality characteristics such as mechanical stability and head touch. In addition, taking capacitor applications as an example, it means that the capacitors function as designed after they have been installed in the equipment.The withstand voltage characteristics, frequency characteristics, capacity uniformity, and heat
It refers to quality characteristics such as stability against mechanical shock. Further, the handling property is a quality in the middle of processing for achieving the final quality. That is, taking a magnetic material as an example, the suitability of the magnetic powder coating step is good,
The tape has good winding characteristics, it can be dubbed at high speed, and there are no wrinkles, surface scrapes, or falling during these processing steps. Further, taking a capacitor application as an example, it is that wrinkles during vapor deposition processing and wrinkles due to heat do not easily occur, winding characteristics are good, and element winding characteristics of capacitors are good. All of these characteristics are represented by the surface roughness and slipperiness of the film as the quality characteristics of the base film, but in some cases they can be expressed by secondary characteristics such as air entrainment and surface adhesion. is there.

As the inorganic filler used in the present invention,
Inorganic particles such as silicon dioxide, titanium dioxide, zirconium dioxide, calcium carbonate, alumina, talc and kaolin are common. In addition, an aggregate of these inert particles may be used. Further, as the organic filler, particles of high heat-resistant polymer such as styrene, silicone, polymethylmethacrylate, and polyamideimide can be used,
You may use these individually or in combination with the said inorganic filler.

The average particle size of the filler used in the present invention is
The range of 0.01 to 3 μm is preferable. 0.01
If the thickness is less than μm, the surface of the film will not only improve the processing step and the quality of the final product to a small extent even if a filler is added, but if the addition amount is increased in order to exert the effect, thickness unevenness will occur in the subsequent stretching step. It is not preferable because it is easy to cause a breakage or breakage, which makes stretching difficult. On the other hand, it is not practical to apply a thermoplastic resin using a filler larger than 3 μm to the film of the present invention having the thickness and required quality.

When a type having a very smooth surface such as a magnetic material is required, the filler to be added is a monodisperse filler having an average particle size of 0.01 to 1.0.
It is preferable to add one or more types of filler having a size of μm. On the other hand, in the case of a film for which a relatively rough surface is preferred such as a capacitor application, an aggregate filler can be appropriately used in addition to the monodisperse filler. In this case, it is preferable that the monodisperse filler has an average particle diameter of 0.01 to 1.0 μm, and the aggregate filler has an average particle diameter of 0.2 to 3 μm. In the present invention, with respect to the particle diameter when several kinds of particles are added, the average value of the larger particle diameter distribution is referred to as the average particle diameter. Here, if the average particle size of the aggregated particles is 0.2 μm or less, no effect is obtained. On the other hand, if it is 3.0 μm or more, the load applied to the filter becomes too large when the filtration according to the present invention is used, which is not practical.

In addition to the average particle diameter δ, the filler used in the present invention has a standard deviation σ of 0.
It is 1δ or more. If the standard deviation is 0.1δ or less, the distribution of the particle size is limited to a narrow range, and it is effective in dispersing the filler aggregated again after being melted in the extruder, but one of the major objects of the present invention. The purpose and effect of “filtering a filler that is coarser than the average particle size with a filter” is diminished.

The preferred amount of filler added is 0.0
The content is from 01 to 1.0% by weight, but if the filtration capacity is sufficient, the content is not limited to this range and may be used. Of course 0.0
If it is less than 01% by weight, there is no effect. Incidentally, in the filler production step or the thermoplastic resin production step, the filter of the present invention is used to cut coarse particles of several times to several tens times the average particle diameter to regulate the distribution of the filler, and melted using an extruder. Then, it is more effective and preferable to discharge from a wide die by using the method of the present invention when forming a sheet.

The media made of metal fibers are arranged such that their fiber axes are parallel to the media layer (direction orthogonal to the flow direction of the molten thermoplastic resin (right angle direction)). Apparent porosity becomes large when the fiber axis is also arranged in the thickness direction of the medium, and it looks as if it is preferable, but for the purpose of the present invention of accurately filtering by using a plurality of extremely thin media layers,
This is not preferable because it only increases the loss of voids between the effective metal fibers.

Further, the medium composed of metal fibers is constructed so that the material diameter and the basis weight satisfy the relations of the above expressions (2) and (3). Equation (2) shows that, for example, when a material with a large diameter is used in a medium requiring strength, the weight of the material is reduced, and a material with a small diameter is used for the medium for controlling the filtration accuracy, and the weight of the material is increased. is important. In the present invention, this preferable range is 400 to
16000. If it is less than 400, sufficient filtration cannot be performed, which is not preferable. Further, if it is 16000 or more, the density in the thickness direction of the filtration layer increases, and the efficiency of filtration inside decreases, which is not preferable.

Equation (3) shows the overall state of the media constructed by stacking, and is important for achieving effective filtration. The number of layers is not particularly limited as long as it is 2 or more, but preferably 3 or more, more preferably 4 or more. In addition, it is preferable to stack several tens of layers so as to have a structure as if (w × d) _n are continuous, since a large filtration capacity can be obtained.

The porosity of these media is 35 to 9
0%. It is preferably 50 to 80%, more preferably 65 to 75%. If it is less than 35%, it becomes difficult to carry out effective filtration, which is not preferable. On the other hand, when it is 90% or more, the medium cannot withstand the filtration pressure, which is not preferable. Furthermore, the difference in porosity between adjacent media to be stacked is 1
5% or less, more preferably 10% or less,
This is not the case.

The basis weight of each medium is 100 to
10000 g / m ² is preferred. Do not filtration can sufficient for 100 g / m ² or less is not preferable because filtered clogging is increased in 10000 g / m ² or more. Here, the basis weight is the weight per unit filtration area of the material forming the medium. The material diameter is 30 μm or less.
If it exceeds 30 μm, it is difficult to obtain the filtration accuracy targeted by the present invention, which is not preferable. Here, the material diameter of the metal fiber is usually its average diameter, and when a different diameter material having a major axis and a minor axis in the form of a metal fiber is used, the minor axis is referred to as the material diameter.

In the lamination of the filter in the present invention, the individual media may be sintered and then laminated, or the metal fibers forming the individual media may be respectively laminated and then integrally sintered. . The term "sintering" as used herein means that powder particles are bonded at a temperature lower than the melting point of the substance, and its characteristics are described in detail, for example, in "Handbook of Metals (edited by The Japan Institute of Metals, published by Maruzen)". As is done.

The filtration accuracy is determined by the gap between the metal fibers and the length of passage of the thermoplastic resin. The filler added to the thermoplastic resin is present in the thermoplastic resin film by the method of the present invention, It is important to achieve the most effective quality characteristics. Filtration accuracy should be determined from the thickness of the thermoplastic resin film, the size of the filler used, and the required quality. If more flatness and smoothness are required, a filtration accuracy of 10 μm or less, and further flatness and smoothness are required. If required, a filtration accuracy of 5 μm or less may be required. Further, when a film having an ultra-smooth surface is required, a filter having a filtration accuracy of 1 μm or less can be used, and a filter having a filtration accuracy of 0.5 μm or less can also be used. On the other hand, when a film having a rough surface is required, a film having a filtration accuracy of 30 μm or less may be used.

Further, in the present invention, it is necessary that the average particle size of the filler used in the thermoplastic resin and the filtration accuracy are kept in the relationship of the formula (1). Here, the filtration accuracy is JIS
The particle size (μm) of which 11% or dust ACFTD specified in Z8901-1974 is used and 95% of which is cut. That is, the formula (1) is achieved by filtering 95% or more of particles on the side that is more than 2.5 times larger than the average particle diameter of the filler and less than 50 times smaller than the average particle diameter. That is, it is important to physically remove particles on the rougher side than this range. The range of formula (1) is preferably 3 to 30, more preferably 4 to 20.
When it is 2.5 or less, the load for filtering the filler becomes extremely high, which is not preferable. Further, when it is 50 or more, the effect of the present invention becomes difficult to be obtained, which is not preferable. On the other hand, the formula (1) also represents the difficulty of the filler passing through the filter, and when the selection of the filler and the filtration accuracy are sufficiently taken into consideration according to the present invention, the filtration operation becomes easy, which is preferable.

Furthermore, the filter of the present invention is required to have a flow resistance r by air of 35 mmH ₂ O or more. In the case of a medium exhibiting a flow resistance of less than 35 mmH ₂ O, the effect of cutting coarse particles of the added filler and the dispersion effect of aggregation are poor, and the collection efficiency is also poor. Preferably 50m
mH ₂ O or more, more preferably 60 mmH ₂ O or more.

In the laminated filter of the present invention, for example, when the filter composed of the medium of the present invention is housed in a casing having the same volume, the number of filters used is reduced and the apparent filtration area is reduced. However, the substantial filtration capacity is improved.

As the metal of the filter medium used in the present invention, stainless steel, bronze, copper or the like can be used, but stainless steel is preferable from the viewpoint of activity with a thermoplastic resin and recycling. Among stainless steel, SUS304, SUS316, SUS316
L, SUS410, SUS430 and the like are preferable, but not limited thereto. Further, it may be preferable to use a medium obtained by sintering a multi-component system in which these various metals and various stainless steels are mixed, because the void interface inside the sintered body has a function that has not been found in the past.

The extruder that can be used in the present invention is a screw type extruder, preferably a single-screw or twin-screw extruder. The thermoplastic resin has a melting point of several tens of degrees Celsius or more. It is important that uniform melting be possible without any abnormal temperature rise.

The range of the melt viscosity of the thermoplastic resin which can be filtered through the filter in the present invention is 200 to 12
It is 000 poise. When it is less than 200 poise, the filter of the present invention does not increase the filtration resistance and it becomes difficult to effectively utilize the entire surface of the medium of the present invention, which is not preferable. On the other hand, if the melt viscosity is more than 12000 poise, filtration resistance through the filter of the present invention becomes too large, which increases the risk of deformation of the media and collapse of the media layer, which is not preferable. The viscosity of the thermoplastic resin varies depending on the molten state. That is, since the melt viscosity varies depending on the molecular weight and the melting temperature of the thermoplastic resin, for example, when passing through a filter configured as in the present invention, the melt viscosity should be controlled to be adjusted to 200 to 12,000 poise. is important. By doing so, it is possible to prevent the nonuniform flow of the molten thermoplastic resin that is caused by the abnormally high filtration resistance and the damage of the filter or the abnormally low filtration resistance, and the uniform discharge of the thermoplastic resin can be achieved. It becomes possible, and it is possible to use it in an optimum state including the collection efficiency of the filter.

Here, as an apparatus for adjusting the melt viscosity of the melted thermoplastic resin to the melt viscosity of the present invention, for example,
A general method is to control the external heating temperature of the extruder. A thermometer is installed in front of the filter device, and the viscosity can be calculated from the temperature of the molten thermoplastic resin according to the temperature-viscosity relationship, and can be fed back to the temperature control unit of the extruder for adjustment. As a more preferable adjusting method, it is preferable to adjust the viscosity of the molten thermoplastic resin immediately before entering the filter, because it can be easily adjusted, the adjustment range is widened, and thermal deterioration of the thermoplastic resin can be suppressed. That is, with a jacket capable of heating and cooling at the same time, the temperature of the thermoplastic resin is adjusted within a short time by passing it through a melt viscosity adjusting device having a structure capable of exchanging heat with the thermoplastic resin. The melt viscosity can be adjusted. It is more preferable to install a static mixer or the like inside the temperature control device or on the outlet side thereof so that the thermoplastic resin after heat exchange does not have temperature unevenness. Also in the present melt viscosity adjusting device, the temperature of the thermoplastic resin is detected on the outlet side thereof, and is fed back to the temperature control unit for adjustment according to the temperature-viscosity relationship.

In the above, it is preferable to enclose a liquid in the jacket for facilitating heat exchange from the viewpoint of heat exchange efficiency and temperature unevenness, and circulate the liquid between the temperature control unit, but not limited to this. , Electric heater, air,
A heat exchange system combining water and the like may be used. Also,
The melt viscosity adjusting device used in the present invention is preferably applied to the thermoplastic resin after passing through the filter so as not to be held at an abnormally high temperature for a long time. This does not apply if the time taken to complete is short.

Furthermore, it is advisable to detect the pressure of the molten thermoplastic resin before entering the filter device to prevent an abnormally high pressure from being applied to the filter and to install a pressure gauge for detecting clogging of the filter.

The die of the present invention is preferably used in a T shape, a coat hanger shape, a fish tail shape or the like. Further, two or more extruders may be installed on the upstream side of the die in the present invention, and a type of laminating using a feed block or a die of laminating in the die may be used. As a matter of course, the filter according to the present invention can be used between each of these extruders and the die to perform the filtration that is the object of the present invention.

The thermoplastic resin sheet can be molded by discharging it onto a rotating drum whose temperature is controlled below the glass transition temperature of the thermoplastic resin and quenching it. In order to improve the cooling efficiency, it is preferable to use an electrostatic casting method, a method of spraying an air jet, a method of forming a thin water film on the drum, or the like so as to bring them into close contact with the rotating drum, because the rapid cooling efficiency increases.

Further, the thermoplastic resin sheet is heated to a temperature near the glass transition temperature or higher by a longitudinal stretching machine and stretched 3 to 7 times, and both ears are gripped by clips and guided to a transverse stretching machine. An extremely high quality biaxially stretched thermoplastic resin film can be obtained by heating above the glass transition temperature and stretching 3 to 5 times, and heat setting at a temperature below the melting point.

[0041]

The present invention will be described in more detail with reference to the following examples. The measuring method used was as follows. (1) Average particle size and standard deviation The area of particles is determined from a transmission electron micrograph, and the average value and standard deviation of all observed particles are determined as the diameter of a circle having the same area.

(2) Filtration accuracy 11 kinds of test powder JIS-Z8901-1974 or dust ACFTD were dispersed in distilled water, the particle size distribution was measured by HIAC, and compared with the particle size distribution after passing through the filter. The 95% cut value is used as the filtration accuracy.

(3) Porosity The volume of the space is calculated from the volume of the medium, the amount of the material used, and the specific gravity, and expressed as a percentage.

(4) Unit weight The weight of the material used per unit filtration area of the media is expressed (unit: g / m ² ).

(5) Material diameter The material diameter of the particles is measured by a micrograph and the average diameter is determined. In the case of different diameters having a long diameter and a short diameter, the short diameter is measured and the average diameter is used.

(6) Cross-section of filter media After the filter media is hardened with an epoxy resin, it is cut along the longitudinal or flat cross-section of the media, the cut surface is polished, and then a metallographic photograph is taken to examine the axial direction of the metal fibers. Observe the arrangement, material diameter, and void condition.

(7) Flow resistance A pair of hemispherical upper and lower cups having air flow holes seal the outer circumference of a filter having an effective diameter of 40 mm to 0.5 l.
/ Min.・ Read the difference between the air pressures in the upper and lower cups with a manometer when flowing cm ² of air.

(8) Surface roughness Ra, Rz, and Rmax are measured at 10 points with a length of 4 mm and a cutoff of 0.8 mm in accordance with JIS-B0601, and the average is taken.

(9) Dielectric Breakdown Voltage According to JIS-C2318, electrical insulation characteristics are measured by the element method, and the average breakdown voltage at that time is compared.

(10) Intrinsic viscosity Measured at 25 ° C. using orthochlorophenol as a solvent.

(11) Melt viscosity The viscosity of the heat-melted thermoplastic resin is measured by a Koka type flow tester to prepare a calibration curve of a temperature-viscosity curve.
The viscosity of the thermoplastic resin when melted is calculated from the calibration curve by detecting the temperature.

(12) Coarse protrusions A thermoplastic resin film is attached to a smooth glass cylindrical surface, and a Newton's ring formed when a light beam of a sodium lamp is irradiated is observed under a microscope to determine the number of double rings or more to 100c.
Count on the area of m ² .

[Example] The material of the filter is SUS
Using 316 L of stainless metal fibers having various wire diameters, the media shown in Tables 1, 3, and 5 were laminated and configured and sintered. The upper side of the table is the upstream side. The flow resistance due to air at this time is shown in the same table, and an example of a typical cross section of the metal fiber in the longitudinal section of the media layer and in the direction perpendicular to the flow (metal fiber axial direction) is shown in FIG. In the micrograph of FIG. 1, the white portion represents the cross section of the metal fiber, the left photograph shows the vertical cross section of the filter having the portions 101 and 102 from the upstream side, and the right photograph shows Part 10
The cross-sectional view (plan cross-sectional view) in the plane direction of 1 and 102 (direction parallel to the filter surface) is shown.

As a filter device, as shown in FIG.
1 ', the media 2 and 2'on the downstream side, are molded into a disk-shaped filter having a diameter of 12 inches, and two disk-shaped filters are combined to withstand the filtration pressure and melt heat inside the two filters. A stainless wire mesh 3 made of SUS304 is used as a support for securing a space through which the plastic resin can flow, the outer periphery is welded (welded portion 4), and the inner peripheral portion has a circular discharge hole 6 in the central portion. The seal ring 5 was welded (welded portion 4 ') so that the molten thermoplastic resin was collected at the radial center of the filter.

This disc-shaped filter 10 is piled up and shown in FIG.
The filter device was assembled as follows. In FIG. 3, a plurality of disc-shaped filters 10 are stacked and assembled by using a plurality of filter trees 30 as a support, and housed in filter casings 20 and 20 '. The molten thermoplastic resin is introduced through the thermoplastic resin introduction hole 40, filtered by each filter 10, and then the thermoplastic resin discharge hole 5
Emitted from 0.

As shown in FIG. 4, a single-screw extruder 60 having a diameter of 90 mm is used as an extruder and its motor 61 is used.
By controlling the number of revolutions of No. 2 via the motor control device 62, the number of revolutions of the screw, the melting of the raw material charged from the hopper 63, the discharge amount, etc. were controlled. Further, as a melt viscosity adjusting device 70 for the thermoplastic resin, a high mixer 71 equipped with a jacket 72 for circulating a liquid for temperature control was used to pass through this and adjust the viscosity of the thermoplastic resin. The conversion of temperature-viscosity is obtained by measuring the viscosity in advance with a flow tester for each type of thermoplastic resin, inputting a calibration curve into the computer, converting it from temperature to viscosity, and calculating the difference from the desired viscosity. The required temperature was fed back to the liquid temperature control unit.

Further, a pressure detecting device 81 is installed at the inlet of the filter device 80 to measure the pressure applied to the filter and to stop the motor 61 of the extruder when an abnormally high pressure is applied. I tried to activate the lock. In addition, the pressure at the inlet of the filter device 80 is 250 kg after the thermoplastic resin starts passing through the filter.
The total passing amount up to / cm ² was calculated from the rate of increase of the pressure, and was taken as the filtration capacity per unit filtration area. As the wide base 90, a T-shaped base with a width of 550 mm is used.
It was discharged onto a cooling drum 92 as a rotary cooling body having a diameter of 700 mm. The surface temperature of the cooling drum 92 was 20 ° C. In addition, electrostatic pinning 91 was used to bring the thermoplastic resin sheet into close contact with the drum 92.

Examples 1 to 3 (Tables 1 and 2) As a thermoplastic resin, the average particle diameter δ and the standard deviation σ of the silica particles of Table 1 were 0.15% by weight, respectively, and the intrinsic viscosity (IV) was 0.595 to 0.61 of polyethylene terephthalate was dried by a conventional method, and the extruder was operated at 280 ° C.
After melt-extruding with, the mixture was filtered through a viscosity adjusting device and a filter device. Table 1 shows the constitution and characteristics of the filter used for filtration.

Then, it was rapidly cooled with a rotary cooling body, stretched by a longitudinal stretching machine at 98 ° C. to 3.6 times, and further stretched by a transverse stretching machine at 105 ° C.
Stretched to 3.9 times and heat set at 200 ° C.
Cooled at ° C. Table 2 shows the characteristic values such as surface roughness and surface protrusion of the biaxially stretched polyethylene terephthalate film having a thickness of 9 µm, which was relaxed by 4% in the transverse direction by heat setting and cooling.

Comparative Examples 1 to 5 (Tables 1 and 2) The same filters as in Example 1 were used and the average particle size was 2.2 μm.
m, a polyethylene terephthalate containing a filler having a standard deviation of 0.4 μm (Comparative Example 1), the same polyester as in Example 1 was used, and the same polyester as in Example 3 was used with the filters of Comparative Example 2 and Comparative Example 5. The filter of Comparative Example 3 was used to pass the polyester of Example 2 using the filter of Comparative Example 4, and the polyester was discharged onto a rotary cooling body by the same device as that of Example, biaxially stretched and heat-set after molding. Table 2 shows the characteristic values of the polyethylene terephthalate film. Here, the filter of Comparative Example 5 is SUS31.
It is a filter composed of a single layer medium of 6 L metal fiber.

Examples 4 and 5 (Tables 3 and 4) As the thermoplastic resin, 0.2 agglomerated silica having a primary particle size of 0.02 μm, an average particle size of 2.8 μm and a standard deviation of 0.6 μm was used. % By weight and 0.3% by weight of aluminum silicate having an average particle size of 0.4 μm added to give an intrinsic viscosity of 0.1.
61 polyethylene terephthalate (Example 5), primary particle size 0.02 μm and average particle size 2.
Agglomerated silica with a standard deviation of 0.5 μm at 2 μm is 0.
15% by weight of polyethylene terephthalate having an intrinsic viscosity of 0.65 to which 0.1% by weight of calcium carbonate having an average particle diameter of 0.6 μm was added (Example 5) was dried by a conventional method, and the extrusion was performed. Melt extruding at 280 ° C.
It filtered through the viscosity control apparatus and the filter apparatus. Table 3 shows the constitution and characteristics of the filter used for filtration. After that, it is rapidly cooled with a rotary cooling body, and 110 ° C. in a longitudinal stretching machine.
It was stretched 5 times, further stretched 3.8 times at 115 ° C. by a transverse stretching machine, heat-set at 200 ° C., and cooled at 130 ° C.
It was relaxed by 3% in the transverse direction from heat setting to cooling to obtain a biaxially stretched polyethylene terephthalate film having a thickness of 4.5 μm. Along with the characteristic values, a capacitor element was prepared and the withstand voltage characteristics are shown in Table 4.

Comparative Examples 6 to 8 (Tables 3 and 4) Polyethylene terephthalate having the same formulation as in Examples 4 and 5 was used, and Comparative Examples 6, 7 and 8 were used in the filter device.
Using the same media as in the example, the composition was discharged onto a rotary cooling body by the same apparatus as used in the example, and after forming, a capacitor element was prepared and the withstand voltage characteristics are shown in Table 4 together with the characteristic values of the polyethylene terephthalate film which was biaxially stretched and heat-set. . Comparative Example 7
Was a filter composed of a single-layer medium obtained by sintering metal fibers made of SUS316L. Comparative Example 8
Used a filter composed of a single-layer medium obtained by sintering metal powder of SUS430.

Comparative Example 9 In Example 1, the temperature of the viscosity adjusting device was adjusted so that the melt viscosity was 190 poise. The molten thermoplastic resin discharged from the die is different in the speed and time of passing through the filter,
A sheet could not be formed due to uneven viscosity and uneven color.

Comparative Example 10 The polyethylene terephthalate of Example 1 was placed in a heating and depressurizing apparatus before the drying thereof and solid-phase polymerized to obtain an intrinsic viscosity of 0.85. When the temperature of the extruder and the viscosity adjusting device was set to 295 ° C. and the mixture was fed into the filter device of Example 1, the pressure gauge at the inlet became 250 kg / cm ² or more, the interlock was turned on, and the motor of the extruder stopped. The melt viscosity at this time was 13,000 poise in conversion.

Example 6 (Tables 5 and 6) 0.3% by weight of agglomerated silica particles having a primary particle diameter of 0.02 μm, an average particle diameter of 1.8 μm and a standard deviation of 0.4 μm as a thermoplastic resin. And an intrinsic viscosity of 0.2% by weight of aluminum silicate having an average particle diameter of 0.3 μm is 0.
Polyethylene terephthalate (63) was dried by a conventional method, melt-extruded at 285 ° C. by the above extruder, and then filtered through a viscosity adjusting device and a filter. The constitution and characteristics of the filter used for filtration are shown in Table 5.

After that, it is rapidly cooled with a rotary cooling body, and 1 with a longitudinal stretching machine.
The film was stretched 3.3 times at 00 ° C., further laterally stretched at 110 ° C. 3.6 times, heat-set at 225 ° C., and cooled at 150 ° C.
From heat setting to cooling, relax 3% laterally to 2.2
A polyethylene terephthalate film having a thickness of μm was obtained. The characteristics and withstand voltage characteristics are shown in Table 6.

Comparative Example 11 (Tables 5 and 6) Polyethylene terephthalate having the same formulation as in Example 6 was used, passed through the filter in Table 5, discharged onto a rotary cooling body by the same apparatus as in Example, and molded. Table 6 shows the characteristics and withstand voltage characteristics of the biaxially stretched and heat-fixed polyethylene terephthalate film.

[0068]

[Table 1]

[0069]

[Table 2]

[0070]

[Table 3]

[0071]

[Table 4]

[0072]

[Table 5]

[0073]

[Table 6]

[0074]

According to the present invention, it is possible to physically and efficiently cut a coarse filler having a particle size distribution of the filler added to the thermoplastic resin, and to disperse the re-aggregated filler after melting to aggregate it. It is possible to prevent the appearance of large protrusions due to, and to provide a filter with improved filtration capacity,
It is possible to easily provide a thermoplastic resin film having both good processability and required quality, such as a magnetic material base film with few coarse protrusions and a capacitor base film with improved electrical characteristics.

[Brief description of drawings]

FIG. 1 is a photomicrograph showing a longitudinal section of a filter made of a sintered medium of metal fibers used in the present invention and a plane section in a direction perpendicular to the flow (axial direction of metal fibers).

FIG. 2 is a cross-sectional view of a filter used in an example.

FIG. 3 is a cross-sectional view of a filter device used in an example.

FIG. 4 is a schematic configuration diagram of a thermoplastic resin sheet molding apparatus according to the present invention.

[Explanation of symbols]

 1, 1'Upstream side metal fiber medium 2, 2'Downstream side metal fiber medium 3 SUS wire mesh 4, 4'Welded part 5 Seal ring 6 Discharge hole 10 Filter 20, 20 'Filter casing 30 Filter tree 40 Heat Plastic resin introduction hole 50 Thermoplastic resin discharge hole 60 Extruder 61 Motor 62 Motor control device 63 Hopper 70 Melt viscosity adjustment device 71 High mixer 72 Temperature adjustment jacket 73 Temperature control unit 80 Filter device 81 Pressure detection device 90 Base 91 Electrostatic pinning 92 rotating cooling body 101, 102 metal fiber layer

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Claims (11)

[Claims] 1. The average particle size is δ, and the standard deviation σ is 0.
A thermoplastic resin containing one or more inorganic and / or organic fillers of 1δ or more is melted by using an extruder, and the molten thermoplastic resin satisfies the formula (1) with the filler and the filtration accuracy η, and n The product (wd) _n of the diameter d of the metal fiber of the layer and the basis weight w satisfies the formulas (2) and (3), and the axis of the metal fiber is orthogonal to the flow of the molten thermoplastic resin. The media with a porosity of 35 to 90%, which are arranged in, are laminated and filtered through a filter having a flow resistance r by air of 35 mmH ₂ O or more, and then discharged from a die and rapidly cooled to form a sheet. A method for producing a thermoplastic resin film, which comprises molding. 2.5 <η / δ <50 (1) 400 <(wd) _n <16000 (2) (wd) _{n + 1} / (wd) _n ≤2.5 (3) (where (n is the number from the upstream side of the media that constitutes the filter) 2. The production of a thermoplastic resin film according to claim 1, wherein a filter constituted by laminating two or more layers of metal fibers having a material diameter d of 30 μm or less and a basis weight w of 100 to 10000 g / m ² is used. Method. 3. The method for producing a thermoplastic resin film according to claim 1, wherein a filter having metal fibers made of stainless metal is used. 4. The viscosity μ of the molten thermoplastic resin is 200 to 1
The method for producing a thermoplastic resin film according to claim 1, wherein the film is adjusted to 2000 poise and passed through a filter. 5. A film which is discharged from a die and rapidly cooled to be formed into a sheet, and then stretched in a longitudinal and / or transverse direction, and then heat-fixed has a thickness of 0.5 to 25 μm. 5. The method for producing a thermoplastic resin film according to any one of 1 to 4. 6. A thermoplastic resin containing one or more fillers having an average particle diameter δ of 0.01 to 1.0 μm and a standard deviation σ of 0.1δ or more, and a center line average roughness Ra of the film surface is 15 nm. Below, 5 coarse projections of H2 or more / 1
The method for producing a thermoplastic resin film according to any one of claims 1 to 5, wherein the film is formed so as to have a size of 00 cm ² or less. 7. A thermoplastic resin containing at least one aggregating filler having a primary particle diameter of 0.01 to 1.0 μm, an average particle diameter δ of 0.2 to 3.0 μm and a standard deviation σ of 0.2δ or more. The center line average roughness Ra of the film surface, the 10-point average roughness Rz, and the maximum roughness Rmax satisfy Rmax ≦ (2δ) ^1/3 Rz Rz ≦ 10δ ^1/2 Ra, and Ra is The method for producing a thermoplastic resin film according to claim 1, wherein the film is formed so as to have a thickness of 10 to 200 nm. 8. The method for producing a thermoplastic resin film according to claim 1, wherein the thermoplastic resin is polyester. 9. A center line average roughness Ra of a film surface using a thermoplastic resin containing one or more fillers having an average particle size δ of 0.01 to 1.0 μm and a standard deviation σ of 0.1δ or more. 5 or less coarse projections of H2 or more at 15 nm or less
A thermoplastic resin film having a size of 100 cm ² or less. 10. A thermoplastic resin containing at least one aggregating filler having a primary particle diameter of 0.01 to 1.0 μm, an average particle diameter δ of 0.2 to 3.0 μm and a standard deviation σ of 0.2δ or more. The center line average roughness Ra and the surface roughness of the film used were 10 and 10.
A thermoplastic resin film in which point average roughness Rz and maximum roughness Rmax satisfy Rmax ≦ (2δ) ^1/3 Rz Rz ≦ 10δ ^1/2 Ra and Ra is 10 to 200 nm. 11. The thermoplastic resin is polyester.
The thermoplastic resin film according to claim 9 or 10.