KR20220162686A - Fluorine resin film and its manufacturing method - Google Patents

Abstract

A film composed of a tetrafluoroethylene-based polymer, having a thickness of 100 to 200 µm, a haze of 8% or less, and a thermal expansion and contraction rate after heating at 180°C for 30 minutes of -1% or more +1 in both the flow direction and the width direction. % or less, film.

Description

Fluorine resin film and its manufacturing method

The present invention relates to a film of a tetrafluoroethylene-based polymer and a method for producing the same.

BACKGROUND OF THE INVENTION While weight reduction and compactness of electronic devices are progressing, flexible printed wiring boards (FPCs) are widely adopted as a lightweight and flexible wiring material as a countermeasure against the wiring amount and space limitation in the device. BACKGROUND OF THE INVENTION [0002] In recent years, with the increase in speed of transmission signals in printed wiring boards, the increase in frequency of signals is progressing. In connection with this, low dielectric characteristics (low dielectric constant, low dielectric loss tangent) in a high frequency region are strongly requested of FPC. In response to these demands, liquid crystal polymers (LCP) having low dielectric properties, syndiotactic polystyrene (SPS), and polyimide (PET) instead of conventional polyimide (PI) and polyethylene terephthalate (PET) have been used as base films used in FPC. A base film composed of phenylene sulfide (PPS) or the like has been proposed.

On the other hand, with the pursuit of improving the design of electronic devices, flexible devices such as flexible displays and touch panels, and electronic devices that use semiconductor elements such as LEDs by reflowing, opportunities to use FPCs in conspicuous places is increasing In such an electronic device or the like, the FPC needs to have transparency.

Although the PI film is excellent in heat resistance, there is a problem in transparency. PET film is excellent in transparency but has low heat resistance, and when used in a flexible printed wiring board, warpage or dimensional change of the base material due to heat during reflow becomes a subject. Tetrafluoroethylene-based polymers such as polytetrafluoroethylene (PTFE) have high transparency, excellent physical properties such as chemical resistance, water and oil repellency, heat resistance, and electrical properties, and have properties such as PI, LCP, SPS, and PPS. Since it has a low dielectric constant and a low dielectric loss tangent even compared to materials, it can be used as a base film for FPC that is transparent and has excellent reflow resistance.

On the other hand, tetrafluoroethylene-based polymers have poor dimensional stability, and misalignment tends to occur at the stage of circuit processing. Therefore, Patent Literature 1 proposes a method of removing the strain by annealing treatment (heat treatment) after forming the film into a film.

International Publication No. 2019/203243

The tetrafluoroethylene-based polymer has crystallinity, and since the crystals tend to grow in the cooling process of the molten molded product, the obtained film tends to have a large haze even if the light transmittance is high. In addition, when the film becomes thick, the deformation is difficult to be eliminated even if heat treatment is performed as in the method of Patent Document 1, and the flatness of the film may be impaired by heat treatment because the dimensional stability is poor.

As a result of intensive studies, the present inventors have found a film having good dimensional stability, low haze, good yield in circuit formation, and compatible with transparency and heat resistance.

An object of the present invention is to provide a film having the above characteristics and a manufacturing method thereof.

The present invention has the following aspects.

<1> An extrusion film composed of a tetrafluoroethylene-based polymer, having a thickness of 100 to 200 μm, a haze of 8% or less, and a thermal expansion and contraction rate after heating at 180 ° C. for 30 minutes in both the flow direction and the width direction of the film -1 to +1%, a film.

<2> The film according to <1>, wherein the tetrafluoroethylene-based polymer is a tetrafluoroethylene-based polymer containing units based on tetrafluoroethylene and units based on perfluoro(alkyl vinyl ether).

<3> The above tetrafluoroethylene-based polymer contains perfluoro(alkyl vinyl ether)-based units and has a polar functional group, or perfluoro(alkyl vinyl ether) for all units The film according to <1> or <2>, which is a tetrafluoroethylene-based polymer containing 2.0 to 5.0 mol% of a unit based on vinyl ether) and having no polar functional group.

<4> The film according to any one of <1> to <3>, wherein the tetrafluoroethylene-based polymer has a melting temperature of 260 to 320°C.

<5> A method for producing the film of any one of <1> to <4> by a T die casting method, wherein the tetrafluoroethylene-based polymer is discharged in a molten state from a die and extruded, and the temperature controlled A manufacturing method including operation cooled by interposing a film between two rolls.

<6> The manufacturing method according to <5>, wherein the temperature of the two temperature-controlled rolls is 150 to 250°C on one side and 80 to 150°C on the other side.

<7> An extrusion molding device having a kneading unit and a hopper connected to the kneading unit is provided, and pellets of a tetrafluoroethylene-based polymer having a melting temperature of 260 to 320° C. are introduced into the hopper and melted in the kneading unit. And when discharging the kneaded melt-kneaded material from the T die to produce a film, the temperature of the pellets at the junction with the kneading section of the hopper is (the melting temperature - 200) to (the melting temperature - 100) The manufacturing method according to <5> or <6>, which further includes an operation of supplying the pellets to the kneading unit after adjusting to the range of °C.

<8> The manufacturing method according to any one of <5> to <7>, wherein the pellets have a diameter of 1.0 to 4.0 mm.

<9> Manufacture of any one of <5> to <8>, wherein the hopper is a multistage hopper including a first end and a second end disposed closer to the kneading section than the first end. Way.

<10> The manufacturing method according to any one of <5> to <9>, wherein the pressure in the end of the hopper closest to the kneading section is 1000 Pa or less.

<11> The extrusion molding device includes a T-die connected to the side opposite to the hopper in the axial direction of the kneading unit, and a stationary mixer provided between the kneading unit and the T-die. <5> to < 10> The manufacturing method of any one of.

<12> Further comprising an operation of discharging the tetrafluoroethylene-based polymer in a molten state from the T die and heating the molten tetrafluoroethylene-based polymer in a non-contact heating unit before contacting the first cooling roll The manufacturing method in any one of <5>-<11> which does.

<13> The manufacturing method according to <12>, wherein a difference between a temperature of the tetrafluoroethylene-based polymer in the T die and a temperature of the first cooling roll is 250°C or less.

<14> The manufacturing method according to <12> or <13>, wherein the absolute value of the difference between the temperature of the tetrafluoroethylene polymer in the T die and the temperature of the non-contact heating part is 70°C or less.

<15> A layered product having a layer made of the film of any one of the above <1> to <4>, and a base material layer made of a base material other than the film.

ADVANTAGE OF THE INVENTION According to this invention, the dimensional stability is good, haze is low, the yield in circuit formation is good, and the film which can make transparency and heat resistance compatible, and its manufacturing method are provided. According to the present invention, it is possible to provide a thick film of around 100 μm that is particularly preferred as a substrate for an antenna substrate. The film of the present invention is colorless and transparent and is useful as a low-loss antenna substrate.

1 is a schematic view showing an embodiment of a film manufacturing apparatus used in this method 1. FIG.
Fig. 2 is a schematic view showing one embodiment of an extrusion molding apparatus that can be used in the present invention.
Fig. 3 is a schematic diagram showing an embodiment of a film manufacturing apparatus used in Method 3.

The terms below have the following meanings.

"Thickness of the film" was determined by using a contact type thickness meter DG-525H (manufactured by Ono Chikki Co., Ltd.) and measuring ruler AA-026 (Φ 10 mm, SR7), measuring the thickness of the film by 10 so that the distances were equal in the width direction. It is the average value of the measured values measured at the points.

"The melting temperature of a polymer" is the temperature corresponding to the maximum value of the melting peak measured by the differential scanning calorimetry (DSC) method.

A "unit" in a polymer means an atomic group based on one molecule of the monomer formed by polymerization of the monomer. The unit may be a unit directly formed by a polymerization reaction, or may be a unit in which a part of the unit is converted into another structure by treating a polymer. Hereinafter, the unit based on the monomer a is simply referred to as "monomer a unit".

"The glass transition point of a polymer" is a value measured by analyzing a polymer by the dynamic viscoelasticity measurement (DMA) method.

The film of the present invention is an extrusion molded film composed of a tetrafluoroethylene-based polymer (hereinafter also referred to as “F polymer”), has a thickness of 100 to 200 μm, has a haze of 8% or less, and is 180° C. for 30 minutes. The thermal expansion and contraction rate after heating is -1 to +1% in both the flow direction (hereinafter referred to as MD) and the width direction (hereinafter referred to as TD) of the film.

The film of the present invention may be a rolled film.

Moreover, as a laminate of the present invention having a layer made of the film of the present invention and a substrate layer made of a substrate other than the film of the present invention, a laminate formed by laminating the film of the present invention and metal foil is preferable. The laminate formed by laminating the film and metal foil of this invention can be suitably used as an FPC by cutting to a predetermined length and processing the metal foil into a transmission circuit (including vias), for example, colorless. It is preferable as an antenna substrate that is transparent and has excellent electrical properties.

In addition, the layer composed of the film of the present invention is hereinafter referred to as "F polymer layer", and the base layer composed of a base material other than the film of the present invention is simply referred to as "substrate layer" hereinafter, unless otherwise specified.

Molding deformation resulting from the production method (melt molding method by extrusion molding) remains in a film of a normal hot-meltable fluororesin. In the film of the present invention, by appropriately controlling the cooling conditions of the resin film during molding as described later, both MD and TD have a thermal expansion and contraction rate of -1 to +1%, and deformation in each direction is small and sufficiently uniform, While excellent in dimensional stability, even if the thickness is 100 to 200 µm, the haze is 8% or less, and the transparency is excellent.

Therefore, it is considered that even in a laminate having such a film layer, since the deformation is small and sufficiently uniform, the thermal shock property is excellent, the deformation is suppressed, and the dimensional stability is excellent. For example, the laminate of the present invention having metal foil as a base layer has high thermal shock resistance when forming through holes or vias when processing it into a printed wiring board, and as a result, a printed wiring board that is unlikely to cause disconnection is obtained. easy.

In addition, the thermal expansion and contraction rate of a film is measured as follows. First, a 12 cm square test piece having two sides along the MD and two sides along the TD was cut out of the film. Next, a line segment with a length of 10 cm is drawn on the surface of the obtained test piece in MD and TD, respectively. Next, after putting this test piece into a 180 degreeC oven for 30 minutes and heating it, it takes it out, and after naturally cooling to 25 degreeC, the length of a line segment is measured again.

The thermal expansion and contraction rate is a value calculated according to formula: {(length of line segment before heating) - (length of line segment after heating)}/(length of line segment before heating) × 100. That is, the thermal expansion and contraction rate is the rate of change (percentage) of the length of the line segment before and after heating. In addition, minus signifies elongation of the film, and plus signifies shrinkage of the film.

The thermal expansion and contraction rate of the film of the present invention is -1 to +1% in both MD and TD of the film, preferably -0.8 to +0.8%, and more preferably -0.5 to +0.5%. When the thermal expansion and contraction ratio is within the above range, wrinkles resulting from deformation of the film are less likely to occur even when heated.

Polymer F in the present invention is a polymer containing tetrafluoroethylene (TFE)-based units (TFE units). Polymer F in the present invention is hot meltable, and its melting temperature is preferably 260 to 320°C, more preferably 275 to 315°C, still more preferably 290 to 310°C. In such a case, the molding processability of the F polymer and the mechanical strength of the film of the present invention are easily balanced.

The glass transition point of polymer F is preferably from 75 to 125°C, more preferably from 80 to 100°C.

As the F polymer, polytetrafluoroethylene (PTFE), a polymer containing TFE units and units based on perfluoro (alkylvinyl ether) (PAVE) (PAVE units) (PFA), hexafluoropropene ( HFP)-based units (FEP) are exemplified, and PFA is preferred. As PAVE, CF ₂ = CFOCF ₃ , CF ₂ = CFOCF ₂ CF ₃ and CF ₂ = CFOCF ₂ CF ₂ CF ₃ (PPVE) are preferable, and PPVE is more preferable.

It is preferable that F polymer has a polar functional group. The polar functional group may be contained in the unit in the F polymer or may be contained in the terminal group of the main chain of the F polymer. Examples of the latter aspect include an F polymer having a polar functional group as an end group derived from a polymerization initiator, a chain transfer agent, or the like, and an F polymer having a polar functional group obtained by subjecting the F polymer to plasma treatment or ionizing radiation treatment. As the polar functional group, a hydroxyl group-containing group and a carbonyl group-containing group are preferable.

As the hydroxyl group-containing group, a group containing an alcoholic hydroxyl group is preferable, and -CF ₂ CH ₂ OH and -C(CF ₃ ) ₂ OH are more preferable.

The carbonyl group-containing group is a group containing a carbonyl group (> C(O)), and examples of the carbonyl group-containing group include a carboxyl group, an alkoxycarbonyl group, an amide group, an isocyanate group, a carbamate group (-OC(O)NH ₂ ), an acid anhydride residue ( -C(O)OC(O)-), imide residues (-C(O)NHC(O)- etc.) and carbonate groups (-OC(O)O-) are preferred, and acid anhydride residues are more preferred do.

When the F polymer has a carbonyl group-containing group, the number of carbonyl group-containing groups in the F polymer is preferably 10 to 5000, more preferably 100 to 3000, and more preferably 800 to 1500 per 1×10 ⁶ carbon atoms of the main chain. more preferable In addition, the number of carbonyl group-containing groups in the F polymer can be quantified by the method described in the composition of the polymer or International Publication No. 2020/145133.

The F polymer is a polymer (1) containing a TFE unit and a PAVE unit and having a polar functional group, and a polar functional group containing a TFE unit and a PAVE unit and containing 2.0 to 5.0 mol% of PAVE units with respect to the total units. A polymer (2) having no is preferred.

These F polymers tend to form fine spherulites in a molded product and easily increase adhesion to other components. As a result, a molded product having excellent surface smoothness, adhesiveness and electrical properties is more easily obtained.

Polymer (1) is preferably a polymer containing units based on TFE units, PAVE units, and monomers having polar functional groups, and 90 to 99 mol% of these units in this order with respect to all units, 0.5 to 0.5% by mole. It is more preferable that it is a polymer containing 9.97 mol% and 0.01-3 mol%. Moreover, as a monomer which has a polar functional group, itaconic acid anhydride, a citraconic acid anhydride, and 5-norbornene-2,3-dicarboxylic acid anhydride (henceforth also described as "NAH") are preferable. As a specific example of polymer (1), the polymer described in International Publication No. 2018/16644 is mentioned.

It is preferable that polymer (2) consists only of a TFE unit and a PAVE unit, and contains 95.0-98.0 mol% of TFE units and 2.0-5.0 mol% of PAVE units with respect to all units. 2.1-5.0 mol% is preferable with respect to all units, and, as for content of the PAVE unit in polymer (2), 2.2-5.0 mol% is more preferable.

In addition, that the polymer (2) does not have a polar functional group means that the number of polar functional groups the polymer has is less than 500 per 1×10 ⁶ of carbon atoms constituting the polymer main chain. 100 or less are preferable and, as for the number of said polar functional groups, less than 50 are more preferable. The lower limit of the number of the polar functional groups is usually zero.

Polymer (2) may be produced using a polymerization initiator or chain transfer agent that does not generate a polar functional group as an end group of the polymer chain, and an F polymer having a polar functional group (the polar functional group derived from the polymerization initiator is the main component of the polymer) It may be produced by fluorinating an F polymer having a chain terminal group, etc.). As a method of fluorination treatment, a method using fluorine gas (see Japanese Unexamined Patent Publication No. 2019-194314 and the like) is exemplified.

The film of this invention may contain resin other than F polymer. However, 80 mass % or more is preferable and, as for content of F polymer contained in a film, 100 mass % is more preferable. Resins other than the F polymer include epoxy resins, polyimide resins, polyamic acids as polyimide precursors, acrylic resins, phenol resins, liquid crystalline polyester resins, polyolefin resins, modified polyphenylene ether resins, and polyfunctional cyanate esters. Resins, polyfunctional maleimide-cyanate resins, polyfunctional maleimide resins, vinyl ester resins, urea resins, diallylphthalate resins, melamine resins, guanamine resins, melamine-urea cocondensation resins, styrene resins, polycarbonate resins , polyallylate resin, polysulfone, polyallylsulfone, aromatic polyamide resin, aromatic polyetheramide, polyphenylene sulfide, polyallyl ether ketone, polyamideimide, and polyphenylene ether.

The film of the present invention may include, for example, an inorganic filler, an organic filler, a thixotropic agent, an antifoaming agent, a silane coupling agent, a dehydrating agent, a plasticizer, a weathering agent, an antioxidant, a heat stabilizer, a lubricant, an antistatic agent, a brightener, a colorant, and a conductive agent. agent, release agent, surface treatment agent, viscosity modifier, flame retardant and the like may be further included.

As the inorganic filler, boron nitride filler, beryllia filler (beryllium oxide filler), silicate filler (silica filler, wollastonite filler, talc filler), and metal oxide (cerium oxide, aluminum oxide, magnesium oxide, oxide, etc.) zinc, titanium oxide, etc.) fillers are preferred. Moreover, at least one part of the surface of the inorganic filler may be surface-treated. Examples of the surface treatment agent used for such surface treatment include polyhydric alcohols, saturated fatty acids, esters thereof, amines, paraffin wax, silane coupling agents, silicones, and polysiloxanes.

The shape of the inorganic filler may be any of granular, acicular (fibrous), plate-like, and the like, and specific shapes include spherical, scaly, layered, lobe-like, aquatic, columnar, crown-like, equiaxed A phase, a leaf, a mica, a block, a flat plate, a wedge, a rosette, a mesh, and a prism.

Hereinafter, the manufacturing method of the film of this invention is demonstrated. The film of the present invention can be preferably produced by a T die casting method (melt extrusion method using a T die) from the viewpoint of being able to adjust the deformation of the film.

The MD and TD deformation of the film by the T die casting method depends on the state (temperature, fluidity) of the molten F polymer and the cooling conditions, until the molten F polymer ejected from the T die is crystallized by the cooling roll. The present inventors have found that it is determined according to the state of. In other words, if the crystallization of the F polymer is controlled by appropriately setting the state of the F polymer and the cooling conditions, the MD and TD thermal contraction rates (strain) of the obtained film are converged within a predetermined range, and also due to suppression of crystal growth, , the present inventors have found that a low haze can be achieved even with a relatively thick film of 100 to 200 μm.

The method for producing a film of the present invention includes an operation in which polymer F is discharged in a molten state from a T die, extruded, and cooled by interposing the film between two temperature-controlled rolls (method 1). Preferably, the temperature of the two rolls subjected to temperature control is 150 to 250°C on one side and 80 to 150°C on the other side. More preferably, one of the two temperature-controlled rolls is a metal roll controlled to 150 to 250°C, and the other is a metal elastic roll controlled to 80 to 150°C.

1 is a schematic view showing one embodiment of a film manufacturing apparatus used in this method 1. FIG. The manufacturing apparatus 10 shown in FIG. 1 includes a T die 20, a first cooling roll (first cooling roll) 30 disposed vertically below the T die 20, a quench roll 301, , Arranged between the 2nd cooling roll 40 provided side by side with the 1st cooling roll 30, the winding roll 50 which winds up the film 1, and the winding roll 50 and the 2nd cooling roll 40 and conveying rolls 61 and 62.

Moreover, you may further equip the 1st cooling roll 30 with the air knife 70, and it is preferable to equip it.

Polymer F is melted by heating in an extruder (not shown) connected to the T die 20, and supplied into the T die 20. The F polymer in a molten state is discharged from the lip 21 of the T die 20 toward the first cooling roll 30 . Next, the discharged F polymer in a molten state is cooled while being brought into contact with the first cooling roll 30 and interposed between the first cooling roll 30 by the rapid cooling roll 301 . Moreover, F polymer is conveyed by the conveyance rolls 61 and 62 after passing the 2nd cooling roll 40. After that, the F polymer is wound around the winding roll 50 as the film 1 . As the first cooling roll 30, it is preferable to use a metal roll capable of temperature control, and as the quenching roll 301, it is preferable to use a metal elastic roll.

Examples of the elastic metal roll include a roll having a surface made of a metal material such as stainless steel and filled with a fluid or an elastic material such as rubber between the surface metal material and the shaft roll. The metal elastic roll includes, for example, a shaft roll formed to be freely rotatable in a substantially cylindrical shape, a cylindrical metal thin film disposed so as to cover the outer circumferential surface of the shaft roll and contacting the film-like object, and these shaft rolls and the metal thin film. It consists of a fluid enclosed in between. The metal elastic roll exhibits elasticity due to the above fluid, and there is a feature that roll compression molding can be performed at a low linear pressure. In the present invention, these characteristics are utilized to contribute to control of film cooling conditions.

As a material of the shaft roll, stainless steel is exemplified. It is preferable that the metal thin film is made of stainless steel and has a thickness of 2 to 5 mm. The metal thin film is preferably flexible or flexible, and preferably has a seamless structure without welded joints. A metal elastic roll provided with such a metal thin film is excellent in durability, and if the metal thin film is mirror-finished, handling similar to that of a normal mirror surface roll can be performed. From the viewpoint of obtaining a film having excellent surface smoothness, it is more preferable that the surface of the elastic metal roll is a mirror-finished roll. As a commercial item of a metal elastic roll, the UF roll of Hitachi Shipbuilding Co., Ltd., and the SF roll of Chiba Machinery Co., Ltd. are mentioned.

By cooling the polymer F in a molten state with a quenching roll 301, preferably a metal elastic roll, through a first cooling roll 30, preferably a metal roll, the film is rapidly cooled to suppress crystal growth, thereby reducing haze. can be lowered, and the accumulation of strain applied to the film interposed between the first cooling roll and the quenching roll can be lowered.

The temperature of the first cooling roll 30 is preferably 150 to 250°C, and the temperature of the rapid cooling roll 301 is preferably 80 to 150°C from the viewpoint of rapidly cooling the film. Further, both the first cooling roll and the quenching roll preferably have mechanisms for passing the heat medium, and preferably have a dual mechanism for passing the heat medium reciprocally in the axial direction. The temperature of the first cooling roll and the temperature of the quenching roll both mean the temperature of the heat medium.

When the quenching roll is a metal elastic roll, it is preferably within a temperature range that does not impair the characteristics of the metal elastic roll itself.

In this method 1, it is preferable to further provide an air knife 70 at a position immediately after the F polymer in a molten state is interposed with the first cooling roll 30 by the quenching roll 301. The air knife 70 uniformly spreads a slit-shaped airflow along a line in the width direction of the first cooling roll 30 from the slit nozzle on the line where the F polymer in a molten state comes into contact with the first cooling roll 30. By spraying, it has a role of pressurizing the 1st cooling roll 30 while cooling the F polymer of a molten state. Similar to the quench roll 301, there is an effect of increasing the cooling efficiency of the F polymer, suppressing the haze of the obtained film, and lowering the thermal expansion and contraction rate.

150-200 degreeC is preferable and, as for the temperature of the air blown out from an air knife, 170-200 degreeC is more preferable. When it is 150°C or higher, the thermal expansion and contraction rate of the film becomes small, and when it is 200°C or lower, the haze tends to be small.

As for the flow rate of the air blown out from the air knife, 10-20 m/sec is preferable.

In the method for producing a film of the present invention, in the present method 1, for example, using the extrusion molding apparatus 11 shown in FIG. It further includes methods (2 of this Act).

Fig. 2 is a conceptual diagram showing an embodiment of an extrusion molding apparatus used in Method 2. In the following description, the right side (front of the melt-kneaded material in the conveying direction) in FIG. 2 is described as a "front end", and the left side (rear side in the conveying direction) is described as a "base end".

An extrusion molding apparatus 11 shown in FIG. 2 includes a hopper 2 and a kneading unit 3 communicating with the hopper 2 . The kneading unit 3 of the present embodiment is constituted by a single screw kneading machine having a cylinder 31 and one screw 32 rotatably formed in the cylinder 31 . When using a uniaxial kneading machine, it is easy to prevent the polymer F from deteriorating when melt-kneading the pellets.

In this case, when the overall length of the screw 32 is L (mm) and the diameter is D (mm), the effective length (L/D) represented by the ratio of the overall length (L) to the diameter (D) is , 30 to 45 are more preferable. When the effective length is within the above range, sufficient shear stress can be applied to the F polymer while preventing deterioration of the F polymer, and the temperature unevenness of the melt-kneaded product can be easily reduced.

On the proximal end side of the cylinder 31, a gear box 33 and a motor 34 are sequentially disposed. A gear (not shown) is connected to the front end of the rotating shaft 341 of the motor 34, and this gear meshes with a predetermined gear (not shown) in the gear box 33.

The gearbox 33 accelerates or decelerates the rotational motion of the rotating shaft 341 and transmits it to the rotating shaft 331 . The tip of the rotating shaft 331 is connected to the proximal end of the screw 32 .

With this structure, the rotation of the motor 34 is transmitted to the screw 32, and the screw 32 is rotated at a predetermined rotational speed. As a result, the melt-kneaded material is transferred from the base end side (left side) toward the front end side (right side) in FIG. 2 .

In addition, a heater 35 is formed on the outer periphery of the cylinder 31 . The pellets (F polymer) supplied into the cylinder 31 are melted by the heating of the heater 35, and are mixed (kneaded) by the rotation of the screw 32 and transported toward the front end side. Thereby, the pellets are melted and kneaded, and the melt-kneaded product is extruded from the tip opening 311 of the cylinder 31.

On the tip side of the cylinder 31 (opposite to the hopper 2 in the axial direction of the kneading section 3), a T die 5 is disposed. The melt-kneaded material extruded from the tip opening 311 of the cylinder 31 is discharged from the lower end opening (discharge port) of the T die 5, and then, as described in Method 1, a film of F polymer is produced. do. Here, it should be understood that the T die 5 in FIG. 2 corresponds to the T die 20 in FIG. 1 (or FIG. 3 described later). In addition, although not shown, a heater is also formed in the T-die 5 .

In this embodiment, a static mixer (static mixer) 6 is provided between the cylinder 31 (kneading section 3) and the T-die 5. This stationary mixer 6 is an element that divides, switches or inverts the flow path of the melt-kneaded material and stirs the melt-kneaded material.

By installing such a static mixer 6, it is not necessary to apply unnecessary external force to the melt-kneaded product, so that the melt-kneaded product can be uniformly kneaded while suppressing deterioration.

A hopper 2 is disposed on the base end side of the cylinder 31 . The hopper 2 of the present embodiment includes a lot-shaped first end 21 and a lot-shaped second end 22 disposed on the side of the kneading unit 3 (cylinder 31) rather than the first end 21 It is composed of a two-stage hopper equipped with.

A heater 211 and a pump P1 are connected to the first end portion 21 . In this way, the pellets supplied into the first end portion 21 can be heated under reduced pressure.

The 1st end part 21 is connected to the 2nd end part 22 via the connection part 212.

A heater 221 and a pump P2 are connected to the second end portion 22 . In this way, the pellets supplied into the second end portion 22 can be heated under reduced pressure.

The second end portion 22 is connected to the cylinder 31 via a connecting portion 222 .

The inner surfaces (inner peripheral surfaces) of the hopper 2 (first end 21 and second end 22) are preferably coated with a resin film. That is, it is preferable that the inner surface of the hopper 2 is lined with resin. This can sufficiently prevent the softened pellets from adhering to the inner surface of the hopper 2. Moreover, as a constituent material of a resin film, fluororesin, such as PTFE, is mentioned.

The pellet used in Method 2 may contain components other than the F polymer, but the content of the F polymer is preferably 80% by mass or more, more preferably 100% by mass. Components other than the F polymer include other resins and additives described above.

Moreover, as a shape of a pellet, a spherical shape and a cylindrical shape are mentioned, and a cylindrical shape is preferable. As for the diameter of a pellet, 1.0-4.0 mm is preferable. If it is a pellet of such a diameter, when heating with the hopper 2, it can fully heat (heat) to the inside while preventing bridging (clogging) in the hopper 2.

In this method 2, after heating the pellets of F polymer in advance in the hopper 2, they are supplied to the kneading unit 3, and the melt-kneaded material melted and kneaded in the kneading unit 3 is subjected to a T die 5 It is discharged from to prepare a film. At this time, the temperature of the pellets in the connection part 222 with the kneading part 3 of the hopper 2 is adjusted in the range of (X-200) - (X-100) degreeC. In addition, X is the melting temperature of F polymer. As for the temperature of the pellet in the connection part 222 with the kneading part 3 of the hopper 2, (X-175) - (X-125) degreeC is preferable. The specific temperature of the pellets is preferably from 70 to 225°C, more preferably from 105 to 195°C. In this case, bridging in the hopper 2 due to the softening of the pellets is unlikely to occur. In addition, since the temperature unevenness of the melt-kneaded product in the kneading section 3 is sufficiently reduced, a film having a uniform thickness and preventing the occurrence of fish eyes is easily obtained.

The pressure in the second end 22 (the end closest to the kneading section 3) is preferably lower than the pressure in the first end 21, preferably 1000 Pa or less, and more preferably 100 Pa or less. This makes it possible to sufficiently remove air in the pellets, prevent formation of a heat insulating layer by air, and easily prevent occurrence of temperature non-uniformity in the melt-kneaded material in the kneading section 3.

The softened pellets are supplied to the kneading unit 3. As for the rotational speed of the screw 32, 10-50 ppm is preferable. As for the heating temperature by the heater 35, (X+30) - (X+50) degreeC is more preferable.

When the pellets are melt-kneaded under the above conditions, a homogeneous melt-kneaded product with little temperature unevenness is easily formed. As a result, the film of the present invention is more easily obtainable.

The melt-kneaded material is supplied to the T die 5 via the stationary mixer 6 and discharged from the T die 5 . The melt-kneaded product discharged from the T die 5 is formed into a film as described in Method 1 and wound around a take-up roll.

Moreover, the extrusion molding apparatus 11 may have a cutting machine as needed.

According to this method 2, a film is molded by uniformly melting and kneading the polymer while suppressing the surging phenomenon to a high degree and without imparting excessive thermal history. For this reason, a wide film with few defects (fish eyes) and sufficient length also in the width direction can be manufactured easily.

The number of fish eyes in the film of the present invention is preferably less than 0.05 per 1 m 2 of the film. The lower limit of the number of fish eyes is zero.

In the method for producing a film of the present invention, in Method 1 or Method 2, polymer F is discharged from a T die in a molten state, and the polymer F in a molten state is heated in a non-contact heating unit before contacting the first cooling roll. (3 of this Act).

Fig. 3 is a schematic diagram showing one embodiment of the film manufacturing apparatus used in this method 3. In the manufacturing apparatus 101 shown in FIG. 3, in the manufacturing apparatus 10 in the present method 1, between the T die 20 and the first cooling roll 30, a pair of heaters ( It is the same as the manufacturing apparatus 10 except that it additionally has a non-contact heating part) 80.

Polymer F is melted by heating in an extruder (not shown) connected to the T die 20, and supplied into the T die 20. The F polymer in a molten state is discharged from the lip 21 of the T die 20 toward the first cooling roll 30 . Then, when the discharged molten polymer passes between the pair of heaters 80, it is heated without contacting the heater 80 and comes into contact with the first cooling roll 30, The quenching roll 301 presses against the first cooling roll 30 and cools. At this time, with the air knife 70 installed in the direction perpendicular to the tangential line in contact with the first cooling roll 30, the slit-shaped air flow is uniformly sprayed in a linear shape in the width direction of the first cooling roll 30, thereby forming a molten state. You may pressurize the 1st cooling roll 30 while cooling the F polymer of. In addition, after passing through the 2nd cooling roll 40, polymer F is conveyed by the conveyance rolls 61 and 62, and is wound around the winding roll 50 as the film 1.

According to this configuration, the F polymer in a molten state discharged from the T die 20 is maintained at a high temperature by heating with the heater 80 even while reaching the first cooling roll 30 . For this reason, since the F polymer in a molten state flowing down toward the first cooling roll 30 maintains relatively high fluidity, it is unlikely to be in a stretched state due to its own weight or the tensile force of the first cooling roll 30. . As a result, the F polymer in the molten state suppresses the bowing phenomenon (orientation of the F polymer in MD and TD) during film formation, and the above-mentioned MD and TD deformation (thermal expansion and contraction) is small. It is guessed that a film is obtained.

In particular, in the configuration shown in Fig. 3, since the F polymer discharged from the T die 20 is heated by the heater 80 on both sides in the thickness direction, the temperature uniformity in the thickness direction is high, and the bowing The effect of suppressing the occurrence of the phenomenon is excellent. In addition, from the viewpoint of further improving the effect of suppressing the occurrence of the bowing phenomenon, it is preferable to configure the heater 80 so that the temperature in the width direction of the F polymer can be made uniform. In this case, what is necessary is just to design the width of the heater 80 sufficiently larger than the length of F polymer in the width direction, for example.

When the temperature of the F polymer in the T die 20 is defined as X ¹ [°C] and the temperature of the heater 80 is defined as Z ¹ [°C], the absolute value of the difference (|X ¹ - Z ¹ |) is preferably 70°C or less, and more preferably 30 to 50°C. In this case, it is possible to keep the temperature of the F polymer high enough until it reaches the first cooling roll 30 while preventing the deterioration of the F polymer. Further, when the die temperature and the die lip temperature are different, X ¹ means the die temperature.

In addition, when the temperature of the first cooling roll 30 is defined as Y ¹ [°C], the difference (X ¹ - Y ¹ ) is preferably 250°C or less, more preferably 200°C or less, and 125 to 175 °C is more preferred. In this case, since the degree of cooling of the polymer F by the first cooling roll 30 becomes more appropriate, MD and TD deformations hardly remain in the resulting film 1, and deformation due to insufficient cooling is also preferably prevented. can do. Specifically, Y ¹ is preferably 150 to 250°C.

In addition, from the viewpoint of further improving the effect of suppressing the occurrence of the bowing phenomenon even during cooling by the first cooling roll 30, the first cooling can make the temperature of the F polymer in MD and TD uniform. It is preferable to constitute the roll 30.

Therefore, the first cooling roll 30 preferably has a structure that has a mechanism for passing the heat medium, and a structure that has a dual mechanism that allows the heat medium to reciprocate and repeatedly pass in the axial direction. In addition, temperature Y ¹ of the 1st cooling roll 30 means the temperature of a heat medium.

In addition, in the structure shown in FIG. 3, although a pair of heater 80 is arrange|positioned, you may make it arrange|position only in one side. In addition, the non-contact type heating unit may be configured with a blower that blows hot air instead of the heater 80 .

In all of Methods 1 to 3, the thickness of the F polymer in a molten state before contacting the first cooling roll 30 (thickness t in FIGS. 1 and 3) is preferably 100 to 200 μm. In this case, the precision of heating by the heater 80 and cooling by the 1st cooling roll 30 improves, and MD and TD deformation|transformation becomes more difficult to remain|survive in the obtained film 1.

When the ratio of the opening degree of the ribs 21 of the T die 20 to the thickness of the finally obtained film 1 (stretching ratio) is large, the molecular chain of the polymer included in the F polymer is in a strongly stretched state , and the polymer molecules are easily oriented. As a result, deformation of MD and TD remaining in the film 1 tends to increase. Therefore, the pulling ratio is preferably 50 or less.

Further, the circumferential speed (circumferential speed S in FIGS. 1 and 3 ) of the first cooling roll 30 is also 2 to 20 m/s from the viewpoint of further reducing deformation of MD and TD remaining in the film 1 minute is more preferable. Moreover, as for the temperature of the 2nd cooling roll 40, 30-90 degreeC is more preferable.

The F polymer (film 1) after being released from the first cooling roll 30 may be subjected to a surface treatment capable of introducing an adhesive functional group to its surface. Examples of such surface treatment include discharge treatment such as corona discharge treatment and plasma treatment, plasma graft polymerization treatment, light irradiation treatment such as electron beam irradiation and excimer UV light irradiation, ytro treatment using a flame, and wet etching treatment using metal sodium. can be heard

By this surface treatment, a polar functional group such as a hydroxyl group, a carbonyl group, or a carboxy group is introduced into the surface of the film 1, and as a result, adhesion to other surfaces is further increased.

Hereinafter, the laminate of the present invention (hereinafter also referred to as "this laminate") will be described.

This laminate is a laminate in which an F polymer layer (a layer made of the film of the present invention) and a substrate layer are laminated in this order. This laminate is obtained by laminating the film of the present invention and a film or sheet-like substrate other than the film of the present invention in a roll-to-roll manner, for example, at a melting temperature of the F polymer to 400 ° C., It is preferable to obtain by the method of heat-pressing at the melting temperature of polymer F - 400 degreeC after overlapping.

A metal and resin are mentioned as a material of the base material layer in this laminated body. Examples of the resin include thermoplastic resins, non-thermal melting resins, uncured products of curable resins, and cured products of curable resins. In particular, metals and heat-resistant resins are preferred.

It is preferable that the base material layer in this layered product is a layer formed of a film-like or sheet-like base material. As the substrate in the form of a film or a sheet, metal foil and a heat-resistant resin film are preferable.

The base material layer in this laminate may also be a resin layer or metal layer formed on the surface of the film of the present invention by means such as coating or plating.

As for the 10-point average roughness of the surface of metal foil, when the base material layer in this laminated body is a layer formed from metal foil, 0.01 micrometer or more and 0.5 micrometer or less are preferable. In this case, the film of the present invention and the metal foil tend to adhere more strongly. For this reason, in the laminated body which has the film of this invention with high film thickness precision, and the printed board obtained by processing it, electrical characteristics are easy to express remarkably.

Specifically, when the substrate layer in this laminate is made of metal foil, the dielectric loss tangent of the polymer F layer of this laminate at a frequency of 10 GHz is preferably 0.0001 to 0.0020.

Examples of the material of the metal foil include iron, copper, nickel, titanium, aluminum, and alloys thereof (stainless steel, nickel 42 alloy, etc.). As the metal foil, a rolled copper foil and an electrodeposited copper foil are preferable.

The surface of the metal foil may be subjected to rust prevention treatment (formation of an oxide film such as chromate). In addition, the surface of the metal foil may be treated with a silane coupling agent. The processing range in that case may be part of the surface of metal foil, or may be all of the surface.

The thickness of the metal foil is preferably 0.1 to 20 μm, more preferably 0.5 to 10 μm.

Moreover, you may use metal foil with a carrier containing two or more layers of metal foil as metal foil. Examples of the metal foil with a carrier include a copper foil with a carrier composed of a carrier copper foil (thickness: 10 to 35 μm) and an ultra-thin copper foil (thickness: 2 to 5 μm) laminated on the carrier copper foil with a release layer interposed therebetween. can If such a carrier-attached copper foil is used, it is possible to form a fine pattern by the MSAP (modified semi-additive) process. As the release layer, a metal layer containing nickel or chromium, and a multilayer metal layer in which the metal layer is laminated are preferable.

As a specific example of metal foil with a carrier, the product name "FUTF-5DAF-2" by Fukuda Metal Foil Industry Co., Ltd. is mentioned.

The base material layer of this layered product may be a metal layer formed by a vapor phase film formation method or a plating method. The metal layer can be formed by, for example, forming a metal seed layer on the surface of the film of the present invention by a sputtering method or an electroless plating method, and further growing a metal from the seed layer by an electrolytic plating method. Before forming the seed layer, you may surface-treat the surface of the film of this invention. Examples of the surface treatment include annealing, corona treatment, plasma treatment, ozone treatment, excimer treatment, and silane coupling treatment.

Examples of the metal to be plated by the electroless plating method include copper and nickel.

As a metal in a seed layer, copper, nickel, chromium, a nichrome alloy, a titanium alloy, etc. are mentioned.

Copper is exemplified as a metal to be plated by the electrolytic plating method.

When the base material layer in this laminate is a layer of a heat-resistant resin film, this film contains at least one type of heat-resistant resin, and may be a single-layer film or a multi-layer film. Glass fibers or carbon fibers or the like may be embedded in the heat-resistant resin film.

When the substrate layer is a layer of a heat-resistant resin film, the present laminate is preferably a laminate having a structure in which the film of the present invention is laminated on both sides of the substrate layer. In this case, since the film of the present invention is laminated on both sides of the heat-resistant resin film, the coefficient of linear expansion of the laminate is remarkably lowered and warping is less likely to occur.

As the heat-resistant resin, polyimide, polyallylate, polysulfone, polyallylsulfone, aromatic polyamide, aromatic polyetheramide, polyphenylene sulfide, polyallyl ether ketone, polyamideimide, liquid crystalline polyester, liquid crystalline poly Esteramide is mentioned, and polyimide (especially aromatic polyimide) is preferable.

In this laminate, which is a heat-resistant resin film having the film of the present invention on both sides, the thickness (total thickness) is preferably 220 μm or more, and more preferably 250 μm or more. As for the said thickness, 500 micrometers or less are preferable. In this structure, the ratio of the thickness of the sum of the two F polymer layers to the thickness of the heat-resistant resin film is more preferably 0.8 or more. As for the said ratio, 5 or less are preferable.

In this case, the characteristics of the heat-resistant resin film (high yield strength, incombustibility) and the characteristics of the F polymer layer (low water absorption) are exhibited in a good balance.

Specific examples of this laminate include a metal foil, a metal-clad laminate having an F polymer layer on at least one surface of the metal foil, a polyimide film, and a multilayer having an F polymer layer on both surfaces of the polyimide film. film can be taken.

As the present laminate, in a preferable embodiment of the laminate in which the substrate layer is a heat-resistant resin film, the heat-resistant resin film is a polyimide film having a thickness of 20 to 100 μm, and the film of the present invention, the polyimide film, and the film of the present invention are and a three-layer film laminated in direct contact in sequence. In this aspect, the thickness of the two films of the present invention is the same, and it is preferable that it is 100-200 micrometers. Moreover, as for ratio of the thickness in the sum total of two films of this invention with respect to the thickness of a polyimide film, 0.5-5 are preferable. The laminated body of this aspect most easily expresses the effect of the above-mentioned laminated body.

Here, the outermost surface (the surface of the F polymer layer opposite to the base material layer) of this laminate may be subjected to further surface treatment in order to further improve its linear expansibility and adhesiveness.

Examples of the surface treatment include annealing treatment, corona treatment, plasma treatment, ozone treatment, excimer treatment, and silane coupling treatment.

As for the conditions in the annealing treatment, it is preferable to set the temperature to 120 to 180°C, set the pressure to 0.005 to 0.015 MPa, and set the time to 30 to 120 minutes.

Examples of the gas used for the plasma treatment include oxygen gas, nitrogen gas, rare gas (such as argon), hydrogen gas, ammonia gas, and vinyl acetate. These gases may use 1 type or may use 2 or more types together.

The metal foil of this laminate (metal foil with F polymer layer) in which the substrate layer is metal foil is etched to form a transmission circuit to obtain a printed board. Specifically, by a method of processing metal foil into a predetermined transmission circuit by etching, or by a method of processing metal foil into a predetermined transmission circuit by an electrolytic plating method (semi-additive method (SAP method), MSAP method, etc.), A printed board can be manufactured.

A printed circuit board made of metal foil with an F polymer layer has a transmission circuit formed of metal foil and an F polymer layer in this order. As a specific example of the structure of a printed board, transfer circuit/F polymer layer/prepreg layer, and transfer circuit/F polymer layer/prepreg layer/F polymer layer/transfer circuit are mentioned.

In manufacturing such a printed circuit board, an interlayer insulating film may be formed on the transmission circuit, or a coverlay film may be laminated on the transmission circuit. These interlayer insulating films and coverlay films may be formed from the film of the present invention.

As mentioned above, although the film of this invention, its manufacturing method, and the laminated body of this invention were demonstrated, this invention is not limited to the structure of the above-mentioned embodiment.

For example, in the structure described above, the film of the present invention and the laminate of the present invention may be substituted with other arbitrary structures, or may be substituted with an arbitrary structure exhibiting the same function.

In addition, the manufacturing method of the present invention may further have other arbitrary steps in the configuration of the above embodiment, or may be substituted with an arbitrary step that produces the same action.

Example

Hereinafter, the present invention will be described in detail by examples, but the present invention is not limited thereto. Details of each component are shown below.

[F Polymer]

Polymer F 1: Polymer having an acid anhydride group containing 98.0 mol%, 0.1 mol%, and 1.9 mol% of TFE units, NAH units, and PPVE units in this order (melting temperature: 300°C)

F polymer 2: a polymer without a functional group containing 98.0 mol% and 2.0 mol% of a TFE unit and a PPVE unit in this order (melting temperature: 300°C)

Further, F polymer 1 has 1000 carbonyl group-containing groups per 1×10 ⁶ carbon atoms in the main chain, and F polymer 2 has 40 carbonyl group-containing groups.

[pellets]

Pellet 1: Pellets of polymer F 1 (diameter: 2.2 mm)

[Measurement of Haze]

The haze (cloudiness) of the films obtained in each Example and the like was measured using NDH5000 (manufactured by Nippon Denshoku Kogyo Co., Ltd.) in accordance with JIS K 7136.

[Heat stretch rate]

In accordance with JIS K 7133:1999, after cutting the film to a size of 120 mm x 120 mm, 100 mm gage lines were drawn in the film flow direction (MD) and width direction (TD), and the length of the gage line was measured. The film was allowed to stand in an oven at 180°C, heated for 30 minutes, and then cooled naturally to 25°C.

Formula: {(length of gauge line before heating) - (length of gauge line after heating)}/(length of gauge line before heating) × 100

[Film Appearance]

The film was left still on the surface of smooth glass, the presence or absence of warpage (curvature) was confirmed, and evaluation was made according to the following criteria.

○: Warpage (curvature) is not observed.

x: Warp (curvature) is confirmed.

[Example 1]

(1) Manufacture of film

Polymer F 1 was fed into an extruder at 350°C, and then extruded from a T die having a width of 1600 mm to a thickness of 125 µm. The die temperature was 350°C and the die lip temperature was 370°C. The extruded polymer F 1 in a molten state is interposed with a quench roll 301, which is a metal elastic roll controlled at 90°C, to a first cooling roll 30 at 200°C, and then toward the first cooling roll, From an air knife (50 mm in height) installed in the tangential and vertical direction in contact with the cooling roll, a slit-shaped air stream of 200 ° C. is uniformly sprayed in a line in the width direction of the first cooling roll 30 at a wind speed of 15 m / sec. After being pressed by one cooling roll 30 and subsequently passing through a 90°C second cooling roll 40, it was taken up by a winding roll 50 heated to 90°C and wound up. The haze of the obtained film (hereinafter referred to as the PFA film (1)) was 0.2% in MD and -0.3% in TD of the thermal expansion and contraction rate after heating at 3% and 180°C for 30 minutes.

In addition, a hopper is connected to the front end of the kneading section of the extruder, and the injection of F polymer 1 is performed by introducing pellet 1 into the hopper, subjecting the hopper to a reduced pressure treatment of 100 Pa or less and heat treatment, and F polymer in the connection section. It was carried out by adjusting the temperature to be 180 ° C. In addition, the F polymer 1 in a molten state extruded from the T die was subjected to heat treatment at 320°C with a non-contact heater before being brought into contact with the quench roll and the first roll.

(2) Manufacture and evaluation of antenna board

A nickel-chromium alloy layer was formed by sputtering a nickel-chromium alloy to a thickness of 10 nm on the PFA film 1 in a roll-to-roll manner, and then, on the nickel-chromium alloy layer, copper was sputtered to a thickness of 200 nm. A copper layer was formed by sputtering. Furthermore, after roll-laminating a dry film resist at 90 degreeC on the copper layer, it exposed and developed so that the mesh width might become 6 micrometers.

By copper sulfate electrolytic copper plating, the mesh portion was plated until the thickness became 6 μm. Thereafter, the dry film resist was peeled off, and then the copper layer and the nickel-chromium alloy layer formed by sputtering were removed by etching to obtain an antenna substrate.

The electrical resistance of the obtained antenna board was measured, and evaluation of whether or not conduction was achieved was performed as being conducted (○)/not conducting (x). In addition, the haze of the antenna substrate after forming the mesh antenna was measured by the method described above.

Table 1 shows film manufacturing conditions, film characteristics, and performance evaluation results as an antenna.

[Example 2]

A film was produced in the same manner as in (1) of Example 1, except that Polymer F 2 was used instead of Polymer F 1, and the air blowing with the air knife was not performed on Polymer F 2 in a molten state using the first cooling roll. (PFA film 2). Using the obtained PFA film 2, an antenna substrate and an antenna were created in the same manner as in (2) of Example 1, and evaluated in the same way. Table 1 shows film manufacturing conditions, film characteristics, and performance evaluation results as an antenna.

[Example 3]

Polymer F 1 is extruded from a T die to a thickness of 125 μm, and the quench roll 301 is not used (ie, the quench roll 301 and the first cooling roll 30 are not interposed), and , Film in the same manner as in (1) of Example 1, except that the film was wound via the first cooling roll without air blowing with the air knife to the F polymer 1 in a molten state with the first cooling roll. was prepared (PFA film 3). Using the obtained PFA film 3, an antenna substrate and an antenna were created in the same manner as in (2) of Example 1, and evaluated in the same way.

Table 1 shows the film production conditions, film properties, and performance evaluation results of the obtained PFA film 3 as an antenna. The PFA film 3 had poor adhesion to the first cooling roll, and "air traces", which are traces of air getting between the film and the first cooling roll, were observed, and the appearance was poor.

Since the film of the present invention is transparent and has excellent dimensional stability, it is useful as a covering material for an antenna. In addition, the film of the present invention can be easily processed into a metal laminate (metal foil with resin), and the resulting processed product is a flexible printed board having transparency, antenna parts, printed boards, sports equipment, food industrial products, etc. It can be applied to various fields, such as medical devices, flexible devices, wearable devices that place importance on design, and medical devices.

In addition, all the content of the JP Patent application 2020-062167, the claim, the abstract, and drawing for which it applied on March 31, 2020 is referred here, and it introduces as an indication of the specification of this invention.

1: film,
10, 101: manufacturing device
20: T die
21 : Lip
30: first cooling roll
301: quench roll
40: second cooling roll
50: winding roll
61, 62: conveying roll
70 : Air knife
80: heater
t : thickness
S: Peripheral speed
11: extrusion molding device
2 : Hopper
21: first end
211: heater
212: connection part
P1: Pump
22: second end
221: heater
222: connection part
P2: Pump
3: kneading part
31: cylinder
311: tip opening
32: screw
33: gearbox
331: axis of rotation
34: motor
341: axis of rotation
35: heater
5: T die
6: Stationary Mixer
L: overall length
D: Diameter

Claims (15)

An extrusion film composed of a tetrafluoroethylene-based polymer, having a thickness of 100 to 200 μm, a haze of 8% or less, and a thermal expansion and contraction rate after heating at 180 ° C. for 30 minutes from -1 to -1 in both the flow direction and the width direction of the film +1%, film. According to claim 1,
The film wherein the tetrafluoroethylene-based polymer is a tetrafluoroethylene-based polymer containing units based on tetrafluoroethylene and units based on perfluoro(alkylvinyl ether). According to claim 1 or 2,
The tetrafluoroethylene-based polymer includes perfluoro(alkylvinyl ether)-based units and has a polar functional group, or perfluoro(alkylvinylether)-based polymer for all units. A film containing 2.0 to 5.0 mol% of a unit based on , which is a tetrafluoroethylene-based polymer having no polar functional group. According to any one of claims 1 to 3,
A film in which the melting temperature of the tetrafluoroethylene-based polymer is 260 to 320 ° C. A method for producing the film according to any one of claims 1 to 4 by a T die casting method, wherein the tetrafluoroethylene-based polymer is discharged in a molten state from a die and extruded, and two temperature-controlled A manufacturing method including operation cooled by interposing a film between rolls. According to claim 5,
The manufacturing method in which the temperature of the two temperature-controlled rolls is 150 to 250°C on one side and 80 to 150°C on the other side. According to claim 5 or 6,
An extrusion molding apparatus having a kneading unit and a hopper connected to the kneading unit, wherein pellets of a tetrafluoroethylene-based polymer having a melting temperature of 260 to 320 ° C. are introduced into the hopper, and melted and kneaded in the kneading unit. When the melt-kneaded material is discharged from the T-die to produce a film, the temperature of the pellets at the junction with the kneading section of the hopper is in the range of (the melting temperature - 200) to (the melting temperature - 100) ° C. After adjusting to, further comprising an operation of supplying the pellets to the kneading unit. According to any one of claims 5 to 7,
The manufacturing method in which the diameter of the said pellet is 1.0-4.0 mm. According to any one of claims 5 to 8,
The manufacturing method in which the said hopper is a multi-stage hopper provided with the 1st end part and the 2nd end part arrange|positioned to the said kneading part side rather than the said 1st end part. According to any one of claims 5 to 9,
The manufacturing method according to claim 1 , wherein the pressure in the end closest to the kneading section of the hopper is 1000 Pa or less. According to any one of claims 5 to 10,
The manufacturing method according to claim 1 , wherein the extrusion molding apparatus includes a T-die connected to a side opposite to the hopper in an axial direction of the kneading unit, and a stationary mixer provided between the kneading unit and the T-die. According to any one of claims 5 to 11,
Further comprising an operation of discharging the tetrafluoroethylene-based polymer in a molten state from a T die and heating the molten tetrafluoroethylene-based polymer in a non-contact heating unit before contacting the first cooling roll, Way. According to claim 12,
The manufacturing method according to claim 1 , wherein a difference between a temperature of the tetrafluoroethylene-based polymer in the T die and a temperature of the first cooling roll is 250° C. or less. According to claim 12 or 13,
The manufacturing method according to claim 1 , wherein an absolute value of a difference between a temperature of the tetrafluoroethylene-based polymer in the T die and a temperature of the non-contact type heating part is 70° C. or less. A laminate comprising a layer made of the film according to any one of claims 1 to 4 and a base layer made of a base other than the film.

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