WO2021200627A1

WO2021200627A1 - Fluororesin film and manufacturing method for same

Info

Publication number: WO2021200627A1
Application number: PCT/JP2021/012798
Authority: WO
Inventors: 渉笠井
Original assignee: Ａｇｃ株式会社
Priority date: 2020-03-31
Filing date: 2021-03-26
Publication date: 2021-10-07
Also published as: TW202146479A; KR20220162686A; CN115335438A; JPWO2021200627A1; CN118438634A

Abstract

Provided is a film constituted by a tetrafluoroethylene-based polymer, the film having a thickness of 100-200 μm, a haze of 8% or less, and a thermal expansion/contraction rate, after heating for 30 minutes at 180℃, of -1% to +1%, inclusive, in both a width direction and a flow direction thereof.

Description

Fluororesin film and its manufacturing method

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

As electronic devices become lighter and more compact, flexible printed wiring boards (FPCs) are widely used as lightweight and flexible wiring materials as a measure against the amount of wiring and space restrictions in the devices. In recent years, as the speed of transmission signals on printed wiring boards has increased, the frequency of signals has been increasing. Along with this, the FPC is strongly required to have low dielectric properties (low dielectric constant, low dielectric loss tangent) in a high frequency region. In response to this demand, liquid crystal polymers (LCP), syndiotactic polystyrene (SPS), and polyphenylene having low dielectric properties are used as base films for FPC, instead of conventional polyimide (PI) and polyethylene terephthalate (PET). A base film composed of sulfide (PPS) or the like has been proposed.
On the other hand, with the pursuit of improving the design of electronic devices, there are opportunities for FPCs to be used in places that are visible to the public, such as flexible devices such as flexible displays and touch panels, and electronic devices that reflow and use semiconductor elements such as LEDs. is increasing. In such electronic devices and the like, the FPC needs to have transparency.

Although PI film has excellent heat resistance, there is a problem in transparency. Although PET film is excellent in transparency, it has low heat resistance, and when it is used in a flexible printed wiring board, warpage and dimensional change of the base material due to heat during reflow become problems. Tetrafluoroethylene-based polymers such as polytetrafluoroethylene (PTFE) have high transparency and are excellent in physical properties such as chemical resistance, water and oil repellency, heat resistance, and electrical properties, and PI, LCP, SPS, etc. Since it has a low dielectric constant and a low dielectric loss tangent as compared with materials such as PPS, 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 are prone to misalignment at the circuit processing stage. Therefore, Patent Document 1 proposes a method of removing the strain by an annealing treatment (heat treatment) after the film is formed.

International Publication No. 2019/202343

Since the tetrafluoroethylene polymer has crystallinity and the crystals easily grow in the cooling process of the melt-molded product, the obtained film tends to have a large haze even if the light transmittance is high. Further, when the film becomes thick, the strain is not easily eliminated even if the heat treatment is performed as in the method of Patent Document 1, and the flatness of the film may be impaired by the heat treatment because the dimensional stability is poor.

As a result of diligent studies, the present inventor has found a film having good dimensional stability, low haze, good yield in circuit formation, and both transparency and heat resistance.
An object of the present invention is to provide a film having the above characteristics and a method for producing the same.

The present invention has the following aspects.
<1> An extruded film composed of a tetrafluoroethylene polymer, having a thickness of 100 to 200 μm, a haze of 8% or less, and a thermal expansion / contraction rate after heating at 180 ° C. for 30 minutes. A film in which both the flow direction and the width direction of the film are -1 to + 1%.
<2> The film of <1>, wherein the tetrafluoroethylene-based polymer is a tetrafluoroethylene-based polymer containing a unit based on tetrafluoroethylene and a unit based on perfluoro (alkyl vinyl ether).
<3> The tetrafluoroethylene-based polymer contains a unit based on perfluoro (alkyl vinyl ether) and has a polar functional group, or a tetrafluoroethylene-based polymer having a polar functional group, or a unit based on perfluoro (alkyl vinyl ether) for all units. A film of <1> or <2>, which is a tetrafluoroethylene-based polymer containing 0.0 to 5.0 mol% and having no polar functional group.
<4> The film according to any one of <1> to <3>, wherein the tetrafluoroethylene polymer has a melting temperature of 260 to 320 ° C.

<5> A method for producing any of the films <1> to <4> by a T-die casting method, in which the tetrafluoroethylene polymer is discharged from a die in a molten state and extruded to control the temperature. A manufacturing method comprising an operation of sandwiching a film between two rolled rolls and cooling the film.
<6> The production method of <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 apparatus having a kneading portion and a hopper connected to the kneading portion is provided, and pellets of a tetrafluoroethylene-based polymer having a melting temperature of 260 to 320 ° C. are charged into the hopper, and the kneading portion is used. When the melted and kneaded melt-kneaded product is discharged from the T-die to produce a film, the temperature of the pellet at the connection portion of the hopper with the kneaded portion is set to (the melting temperature-200) to (the melting temperature-). 100) The production method of <5> or <6>, further comprising an operation of supplying the pellets to the kneading portion after adjusting to a temperature range of 100) ° C.
<8> The production method according to any one of <5> to <7>, wherein the pellet has a diameter of 1.0 to 4.0 mm.

<9> Any of <5> to <8>, wherein the hopper is a multi-stage hopper including a first-stage portion and a second-stage portion arranged on the kneading portion side from the first-stage portion. Manufacturing method.
<10> The production method according to any one of <5> to <9>, wherein the pressure in the step portion of the hopper closest to the kneading portion is 1000 Pa or less.
<11> The extrusion molding apparatus includes a T-die connected to the side opposite to the hopper in the axial direction of the kneading portion, and a stationary mixer provided between the kneading portion and the T-die. , <5> to <10>.
<12> The operation of discharging the tetrafluoroethylene-based polymer from the T-die in a molten state and heating the molten tetrafluoroethylene-based polymer in a non-contact heating unit before contacting with the first cooling roll is further included. , <5> to <11>.
<13> The production method of <12>, wherein the difference between the temperature of the tetrafluoroethylene polymer and the temperature of the first cooling roll in the T-die is 250 ° C. or less.
<14> The production method of <12> or <13>, wherein the absolute value of the difference between the temperature of the tetrafluoroethylene polymer and the temperature of the non-contact heating unit in the T die is 70 ° C. or less.

<15> A laminate having a layer made of any of the films <1> to <4> and a base material layer made of a base material other than the film.

According to the present invention, there is provided a film having good dimensional stability, low haze, good yield in circuit formation, and capable of achieving both transparency and heat resistance, and a method for producing the same. According to the present invention, it is possible to provide a thick film of about 100 μm, which is particularly preferred as a base material for an antenna substrate. The film of the present invention is useful as a colorless, transparent, low-loss antenna substrate.

It is the schematic which shows one Embodiment of the film manufacturing apparatus used in this method 1. It is the schematic which shows one Embodiment of the extrusion molding apparatus which can be used in this invention. It is the schematic which shows one Embodiment of the film manufacturing apparatus used in this method 3.

The following terms have the following meanings.
"Film thickness" is determined by using a contact type thickness gauge DG-525H (manufactured by Ono Sokki Co., Ltd.) and using a stylus AA-026 (Φ10 mm, SR7) to measure the film thickness in the width direction. It is an average value of the measured values measured at 10 points so that is equal.
The "polymer melting temperature" is the temperature corresponding to the maximum value of the melting peak measured by the differential scanning calorimetry (DSC) method.
The "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 processing a polymer. Hereinafter, the unit based on the monomer a is also simply referred to as “monomer a unit”.
The "glass transition point of a polymer" is a value measured by analyzing a polymer by a dynamic viscoelasticity measurement (DMA) method.

The film of the present invention is an extruded film composed of a tetrafluoroethylene-based polymer (hereinafter, also referred to as “F polymer”), which has a thickness of 100 to 200 μm and a haze of 8% or less. The thermal expansion / contraction rate after heating at 180 ° C. for 30 minutes 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 in a wound state.
Further, as the laminate of the present invention having a layer made of the film of the present invention and a base material layer made of a base material other than the film of the present invention, a laminate made by laminating the film of the present invention and a metal foil is used. preferable. The laminate formed by laminating the film and the metal foil of the present invention can be suitably used as an FPC if it is cut to a predetermined length and the metal foil is processed into a transmission circuit (including vias), for example. It is suitable as an antenna substrate that is colorless and transparent and has excellent electrical characteristics.
The layer made of the film of the present invention is hereinafter referred to as "F polymer layer", and the base material layer made of a base material other than the film of the present invention is hereinafter simply referred to as "base material layer" unless otherwise specified.

Molding strain due to the manufacturing method (melt molding method by extrusion molding) remains in the ordinary heat-meltable fluororesin film. The film of the present invention has a thermal expansion / contraction rate of -1 to + 1% for both MD and TD by appropriately controlling the cooling conditions of the resin film during molding, with little distortion in each direction and sufficiently uniform. In addition to being excellent in dimensional stability, haze is 8% or less even when the thickness is 100 to 200 μm, and the transparency is excellent.
Therefore, even in the laminated body having such a film layer, it is considered that the strain is small and the film is sufficiently uniform, so that the thermal shock resistance is excellent, the deformation is suppressed, and the dimensional stability is excellent. For example, the laminate of the present invention using a metal foil as a base material has high thermal shock resistance when forming through holes or vias when processing it into a printed wiring board, and as a result, the printed wiring board is less likely to break. Is easy to obtain.

The thermal expansion / contraction rate of the film is measured as follows. First, a 12 cm square square test piece having two sides along the MD and two sides along the TD is cut out from the film. Next, a line segment having a length of 10 cm is drawn on each of the MD and TD on the surface of the obtained test piece. Next, this test piece is placed in an oven at 180 ° C. for 30 minutes, heated and then taken out, naturally cooled to 25 ° C., and then the length of the line segment is measured again.
The thermal expansion / contraction rate is a value calculated according to the 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 / contraction rate is the rate of change (percentage) of the length of the line segment before and after heating. The minus represents the elongation of the film, and the plus represents the shrinkage of the film.
The thermal expansion and contraction ratio of the film of the present invention is -1 to + 1% for both MD and TD of the film, preferably −0.8 to + 0.8%, and more preferably −0.5 to + 0.5%, respectively. When the thermal expansion / contraction ratio is within the above range, wrinkles due to distortion of the film are less likely to occur even when heated.

The F polymer in the present invention is a polymer containing a unit (TFE unit) based on tetrafluoroethylene (TFE). The F polymer in the present invention is thermally meltable, and its melting temperature is preferably 260 to 320 ° C., more preferably 275 to 315 ° C., and even more preferably 290 to 310 ° C. In such a case, the moldability of the F polymer and the mechanical strength of the film of the present invention are easily balanced.
The glass transition point of the F polymer is preferably 75 to 125 ° C, more preferably 80 to 100 ° C.

F-polymers include polytetrafluoroethylene (PTFE), polymers containing TFE units and units based on perfluoro (alkyl vinyl ether) (PAVE) (PAVE units), polymers containing units based on hexafluoropropene (HFP), and polymers containing units based on hexafluoropropene (HFP). (FEP) is mentioned, and PFA is preferable. As the 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.

The F polymer preferably has a polar functional group. The polar functional group may be contained in a 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 a terminal group derived from a polymerization initiator, a chain transfer agent, etc., and an F polymer having a polar functional group obtained by plasma-treating or ionizing the F polymer. Be done. 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 the carbonyl group-containing group includes a carboxyl group, an alkoxycarbonyl group, an amide group, an isocyanate group, and a carbamate group (-OC (O) NH _2). ), Acid anhydride residues (-C (O) OC (O)-), imide residues (-C (O) NHC (O)-etc.) and carbonate groups (-OC (O) O-) are preferred. , Acid anhydride residues are more preferred.

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, per ^{1 × 10 6 carbon atoms in the main chain.} ~ 1500 pieces are more preferable. The number of carbonyl group-containing groups in the F polymer can be quantified by the composition of the polymer or the method described in International Publication No. 2020/145133.

The F polymer contains a polymer having a polar functional group (1) including TFE units and PAVE units, and 2.0 to 5.0 mol% of PAVE units with respect to all units including TFE units and PAVE units. , The polymer (2) having no polar functional group is preferable.
These F polymers tend to form microspherulites in the molded product and tend to increase the adhesion to other components. As a result, it is easier to obtain a molded product having excellent surface smoothness, adhesiveness and electrical properties.

The polymer (1) is preferably a polymer containing TFE units, PAVE units and units based on a monomer having a polar functional group, and 90 to 99 mol% of these units are added to all units in this order, 0. More preferably, the polymer contains 5.5 to 9.97 mol% and 0.01 to 3 mol%. Further, as the monomer having a polar functional group, itaconic anhydride, citraconic anhydride and 5-norbornene-2,3-dicarboxylic acid anhydride (hereinafter, also referred to as “NAH”) are preferable. Specific examples of the polymer (1) include the polymers described in WO 2018/16644.

The polymer (2) is composed of only TFE units and PAVE units, and contains 95.0 to 98.0 mol% of TFE units and 2.0 to 5.0 mol% of PAVE units with respect to all the units. preferable. The content of PAVE units in the polymer (2) is preferably 2.1 to 5.0 mol%, more preferably 2.2 to 5.0 mol%, based on all the units.
The fact that the polymer (2) does not have polar functional groups means that the number of polar functional groups of the polymer is less than 500 with respect to ^{1 × 10 6 carbon atoms constituting the polymer main chain.} It means that there is. The number of the polar functional groups is preferably 100 or less, more preferably less than 50. The lower limit of the number of polar functional groups is usually 0.
The polymer (2) may be produced by using a polymerization initiator, a chain transfer agent or the like that does not generate a polar functional group as the terminal group of the polymer chain, and is an F polymer having a polar functional group (derived from the polymerization initiator). An F polymer having a polar functional group at the terminal group of the main chain of the polymer) may be fluorinated to produce the polymer. Examples of the fluorination treatment method include a method using fluorine gas (see JP-A-2019-194314, etc.).

The film of the present invention may contain a resin other than the F polymer. However, the content of the F polymer contained in the film is preferably 80% by mass or more, more preferably 100% by mass. Examples of resins other than F polymer include epoxy resin, polyimide resin, polyamic acid which is a polyimide precursor, acrylic resin, phenol resin, liquid crystal polyester resin, polyolefin resin, modified polyphenylene ether resin, and polyfunctional cyanate ester resin. Polyfunctional maleimide-cyanic acid ester resin, polyfunctional maleimide resin, vinyl ester resin, urea resin, diallyl phthalate resin, melamine resin, guanamine resin, melamine-urea cocondensate resin, styrene resin, polycarbonate resin, polyimide resin, polysulfone , Polyallylsulfone, aromatic polyamide resin, aromatic polyetheramide, polyphenylene sulfide, polyallyl ether ketone, polyamideimide, polyphenylene ether and the like.

The film of the present invention is, for example, an inorganic filler, an organic filler, a thixo-imparting agent, a defoaming agent, a silane coupling agent, a dehydrating agent, a plasticizer, a weathering agent, an antioxidant, a heat stabilizer, a lubricant, an antistatic agent, and the like. It may further contain a whitening agent, a colorant, a conductive agent, a mold release agent, a surface treatment agent, a viscosity modifier, a flame retardant and the like.

Inorganic fillers include boron nitride fillers, beryllia fillers (berylium oxide fillers), silicate fillers (silica fillers, wollastonite fillers, talc fillers), and metal oxides (cerium oxide, aluminum oxide, Magnesium oxide, zinc oxide, titanium oxide, etc.) fillers are preferable. Further, at least a 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 waxes, silane coupling agents, silicones, and polysiloxanes.
The shape of the inorganic filler may be granular, needle-like (fibrous), plate-like, etc., and specific shapes include spherical, scaly, layered, leaf-like, apricot kernel, columnar, chicken crown, etc. Shaft-shaped, leaf-shaped, mica-shaped, block-shaped, flat plate-shaped, wedge-shaped, rosette-shaped, mesh-shaped, and prismatic-shaped.

Hereinafter, the method for producing the film of the present invention will be described. 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 adjusting the distortion of the film.
The strain of MD and TD of the film by the T die casting method depends on the state (temperature, fluidity) of the F polymer in the molten state and the cooling conditions, and the molten F polymer discharged from the T die is placed on a cooling roll. The present inventors have found that it is determined by the state until crystallization. In other words, if the F polymer states and cooling conditions are appropriately set to control the crystallization of the F polymer, the heat shrinkage (strain) of the MD and TD of the obtained film converges within a predetermined range, and The present inventors have found that low haze can be achieved even with a relatively thick film of 100 to 200 μm due to the suppression of crystal growth.

The method for producing a film of the present invention includes an operation of ejecting an F polymer from a T-die in a molten state, extruding the film, sandwiching the film between two temperature-controlled rolls, and cooling the film (the present method 1). Preferably, 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. More preferably, one of the two temperature-controlled rolls is a metal roll controlled at 150 to 250 ° C., and the other is a metal elastic roll controlled at 80 to 150 ° C.

FIG. 1 is a schematic view showing an embodiment of a film manufacturing apparatus used in the present method 1. The manufacturing apparatus 10 shown in FIG. 1 is attached to the T die 20, the first cooling roll (first cooling roll) 30 arranged vertically below the T die 20, the quenching roll 301, and the first cooling roll 30. It has a second cooling roll 40, a take-up roll 50 for winding the film 1, and transport rolls 61 and 62 arranged between the take-up roll 50 and the second cooling roll 40.
Further, the first cooling roll 30 may be further provided with an air knife 70, and it is preferable that the first cooling roll 30 is provided with an air knife 70.

The F polymer is melted by heating in an extruder (not shown) connected to the T die 20 and supplied into the T die 20. The melted F polymer is discharged from the lip 21 of the T die 20 toward the first cooling roll 30. Next, the discharged F polymer in the molten state comes into contact with the first cooling roll 30 and is sandwiched between the first cooling rolls 30 by the quenching roll 301 to be cooled. Further, the F polymer is conveyed by the

transfer rollers

61 and 62 after passing through the second cooling roll 40. After that, the F polymer is wound on the take-up 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 metal elastic roll include a roll whose surface is made of a metal material such as stainless steel and whose surface is filled with an elastic material such as fluid or rubber between the surface metal material and the shaft roll. The metal elastic roll is, for example, a shaft roll provided rotatably in a substantially cylindrical shape, a cylindrical metal thin film arranged so as to cover the outer peripheral surface of the shaft roll and in contact with a film-like object, and a shaft thereof. It consists of a fluid enclosed between a roll and a metal thin film. The metal elastic roll exhibits elasticity due to the fluid, and has a characteristic that roll pressure bonding can be performed at a low linear pressure. In the present invention, this characteristic is utilized to contribute to the control of film cooling conditions.
Examples of the material of the shaft roll include stainless steel. The metal thin film is made of stainless steel, and its thickness is preferably 2 to 5 mm. The metal thin film is preferably flexible or flexible, and preferably has a seamless structure without weld joints. A metal elastic roll provided with such a metal thin film has excellent durability and can be handled in the same manner as a normal mirror surface roll if the metal thin film is mirror-finished. From the viewpoint of obtaining a film having excellent surface smoothness, it is more preferable that the surface of the metal elastic roll is a mirror surface roll. Examples of commercially available metal elastic rolls include UF rolls manufactured by Hitachi Zosen Corporation and SF rolls manufactured by Chiba Machinery Co., Ltd.

The melted F polymer is preferably sandwiched between a quenching roll 301, which is a metal elastic roll, and preferably a first cooling roll 30, which is a metal roll, to cool the film, thereby rapidly cooling the film and growing crystals. The haze can be lowered, and the accumulation of strain applied to the film sandwiched 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 quenching roll 301 is preferably 80 to 150 ° C. from the viewpoint of rapidly cooling the film. Both the first cooling roll and the quenching roll are preferably configured to have a mechanism for passing the heat medium, and preferably have a dual mechanism in which the heat medium reciprocates in the axial direction and repeatedly passes through. 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 in a temperature range that does not impair the characteristics of the metal elastic roll itself.

In the present method 1, it is preferable that the air knife 70 is further provided at a position immediately after the molten F polymer is sandwiched between the first cooling roll 30 by the quenching roll 301. The air knife 70 is in a molten state by uniformly blowing a slit-shaped air flow linearly in the width direction of the first cooling roll 30 from the slit nozzle on the line where the molten F polymer contacts the first cooling roll 30. It has a role of cooling the F polymer of No. 1 and pressing it against the first cooling roll 30. Similar to the quenching roll 301, it has the effect of increasing the cooling efficiency of the F polymer, suppressing the haze of the obtained film, and lowering the thermal expansion / contraction rate.
The temperature of the air blown from the air knife is preferably 150 to 200 ° C, more preferably 170 to 200 ° C. If the temperature is 150 ° C. or higher, the thermal expansion / contraction rate of the film is small, and if the temperature is 200 ° C. or lower, the haze tends to be small.
The flow velocity of the air blown from the air knife is preferably 10 to 20 m / sec.

The method for producing a film of the present invention further comprises a method for producing a film from pellets of an F polymer having a melting temperature of 260 to 320 ° C., in the present method 1, for example, using the extrusion molding apparatus 11 shown in FIG. Including (this method 2).
FIG. 2 is a conceptual diagram showing an embodiment of an extrusion molding apparatus used in the present method 2. In the following description, the right side (front of the molten kneaded product in the transfer direction) in FIG. 2 will be referred to as the “tip”, and the left side (rear of the transfer direction) will be referred to as the “base end”.

The extrusion molding apparatus 11 shown in FIG. 2 includes a hopper 2 and a kneading portion 3 communicating with the hopper 2. The kneading portion 3 of the present embodiment is composed of a uniaxial kneader having a cylinder 31 and one screw 32 rotatably provided in the cylinder 31. If a uniaxial kneader is used, it is easy to prevent the F polymer from deteriorating when the pellets are melt-kneaded.
In this case, when the total 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 total length L to the diameter D is more preferably 30 to 45. .. 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 it is easy to reduce temperature unevenness of the melt-kneaded product.

A gearbox 33 and a motor 34 are arranged in order on the base end side of the cylinder 31. A gear (not shown) is connected to the tip of the rotating shaft 341 of the motor 34, and this gear meshes with a predetermined gear (not shown) in the gearbox 33.
In the gearbox 33, the rotational motion of the rotary shaft 341 is accelerated or decelerated and transmitted to the rotary shaft 331. The tip of the rotating shaft 331 is connected to the base end side of the screw 32.
With this configuration, the rotation of the motor 34 is transmitted to the screw 32 to rotate the screw 32 at a predetermined rotation speed. As a result, the melt-kneaded product is transferred from the base end side (left side) to the tip end side (right side) in FIG.

A heater 35 is provided on the outer peripheral portion of the cylinder 31. The pellet (F polymer) supplied into the cylinder 31 is melted by heating the heater 35, mixed (kneaded) by the rotation of the screw 32, and transferred toward the tip side. As a result, the pellets are melted and kneaded, and the melt-kneaded product is extruded from the tip opening 311 of the cylinder 31.
A T-die 5 is arranged on the tip end side of the cylinder 31 (the side opposite to the axial hopper 2 of the kneading portion 3). The melt-kneaded product 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 thereafter, as described in the present method 1, an F polymer film is produced. Here, it may be understood that the T-die 5 in FIG. 2 corresponds to the T-die 20 in FIG. 1 (or FIG. 3 described later). Although not shown, the T-die 5 is also provided with a heater.

In the present embodiment, a static mixer (static mixer) 6 is provided between the cylinder 31 (kneading portion 3) and the T-die 5. The stationary mixer 6 is an element that divides, converts, or inverts the flow path of the melt-kneaded product to stir the melt-kneaded product.
By installing the stationary mixer 6, it is not necessary to apply an unnecessary external force to the melt-kneaded product, so that deterioration of the melt-kneaded product can be suppressed and uniform kneading can be performed.

A hopper 2 is arranged on the base end side of the cylinder 31. The hopper 2 of the present embodiment is a two-stage type including a funnel-shaped first step portion 21 and a funnel-shaped second step portion 22 arranged on the kneading portion 3 (cylinder 31) side of the first step portion 21. It consists of a hopper.
The heater 211 and the pump P1 are connected to the first stage portion 21. As a result, the pellets supplied into the first stage portion 21 can be heated in a reduced pressure state.
The first stage portion 21 is connected to the second stage portion 22 via the connecting portion 212.
The heater 221 and the pump P2 are connected to the second stage portion 22. As a result, the pellets supplied into the second stage portion 22 can be heated in a reduced pressure state.
The second stage portion 22 is connected to the cylinder 31 via the connecting portion 222.
The inner surface (inner peripheral surface) of the hopper 2 (first step portion 21 and second step portion 22) is preferably coated with a resin film. That is, it is preferable that the inner surface of the hopper 2 is lined with resin. As a result, it is possible to sufficiently prevent the softened pellets from adhering to the inner surface of the hopper 2. Examples of the constituent material of the resin film include fluororesins such as PTFE.

The pellet used in this method 2 may contain a component other than the F polymer, but the content of the F polymer is preferably 80% by mass or more, and more preferably 100% by mass. preferable. Examples of the components other than the F polymer include the above-mentioned other resins and additives.
Further, as the shape of the pellet, a spherical shape or a columnar shape can be mentioned, and the columnar shape is preferable. The diameter of the pellet is preferably 1.0 to 4.0 mm. If the pellets have such a diameter, they can be sufficiently heated (heated) to the inside when heated by the hopper 2 while preventing bridging (clogging) in the hopper 2.

In this method 2, the pellets of the F polymer are preheated in the hopper 2 and then supplied to the kneading section 3, and the melt-kneaded product melted and kneaded in the kneading section 3 is discharged from the T-die 5 to produce a film. do. At this time, the temperature of the pellets at the connecting portion 222 with the kneading portion 3 of the hopper 2 is adjusted to the range of (X-200) to (X-100) ° C. Note that X is the melting temperature of the F polymer. The temperature of the pellets at the connecting portion 222 of the hopper 2 with the kneading portion 3 is preferably (X-175) to (X-125) ° C. The specific pellet temperature is preferably 70 to 225 ° C, more preferably 105 to 195 ° C. In this case, bridging in the hopper 2 is unlikely to occur due to softening of the pellets. Further, since the temperature unevenness of the melt-kneaded product in the kneaded portion 3 is sufficiently reduced, it is easy to obtain a film having a uniform thickness and preventing the occurrence of fish eyes.

The pressure in the second stage portion 22 (the stage portion closest to the kneading portion 3) is preferably lower than the pressure in the first stage portion 21, preferably 1000 Pa or less, and more preferably 100 Pa or less. As a result, the air in the pellets can be sufficiently removed, the formation of the heat insulating layer by the air can be prevented, and the temperature unevenness of the melt-kneaded product in the kneaded portion 3 can be easily prevented.
The softened pellets are supplied to the kneading section 3. The rotation speed of the screw 32 is preferably 10 to 50 ppm. The heating temperature by the heater 35 is more preferably (X + 30) to (X + 50) ° C.
If the pellets are melt-kneaded under the above conditions, a homogeneous melt-kneaded product with little temperature unevenness is likely to be formed. As a result, the film of the present invention is more easily obtained.
The melt-kneaded product 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 this method 1 and wound on a take-up roll.
Further, the extrusion molding apparatus 11 may have a cutting machine, if necessary.

According to this method 2, the polymer is uniformly melted and kneaded without giving an excessive heat history while highly suppressing the surging phenomenon to form a film. Therefore, it is possible to easily manufacture a wide film having few defects (fish eyes) and having a sufficient length in the lateral direction.
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 0.

In the method for producing a film of the present invention, in the present method 1 or 2, the F polymer is discharged from the T die in a molten state, and the melted F polymer is brought into contact with the first cooling roll before being contacted with a non-contact heating unit. Further includes a method of heating with (this method 3).
FIG. 3 is a schematic view showing an embodiment of the film manufacturing apparatus used in the present method 3. The manufacturing apparatus 101 shown in FIG. 3 further includes a pair of heaters (non-contact heating portions) 80 arranged to face each other between the T die 20 and the first cooling roll 30 in the manufacturing apparatus 10 according to the first method. It is the same as that of the manufacturing apparatus 10 except that the manufacturing apparatus 10 is used.

The F polymer is melted by heating in an extruder (not shown) connected to the T die 20 and supplied into the T die 20. The melted F polymer is discharged from the lip 21 of the T die 20 toward the first cooling roll 30. Next, when the discharged F polymer in the molten state passes between the pair of heaters 80, it is heated without contacting the heaters 80, comes into contact with the first cooling roll 30, and is brought into contact with the quenching roll 301. 1 It is pressed against the cooling roll 30 and cooled. At this time, the air knife 70 installed in the direction perpendicular to the tangent line in contact with the first cooling roll 30 uniformly blows the slit-shaped air flow linearly in the width direction of the first cooling roll 30 to form a molten state. The F polymer may be cooled and pressed against the first cooling roll 30. Further, the F polymer is conveyed by the

transfer rollers

61 and 62 after passing through the second cooling roll 40, and is wound on the take-up roll 50 as the film 1.

According to this configuration, the molten F polymer discharged from the T die 20 is maintained at a high temperature by heating with the heater 80 even before reaching the first cooling roll 30. Therefore, the molten F polymer flowing down toward the first cooling roll 30 maintains a relatively high fluidity, so that 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, in the molten F polymer, the occurrence of the Boeing phenomenon (orientation of the F polymer toward MD and TD) is suppressed during film formation, and the strain (thermal expansion / contraction ratio) of MD and TD as described above is small. It is presumed that a film can be obtained.

In particular, in the configuration shown in FIG. 3, since the F polymer discharged from the T die 20 is heated by the heaters 80 from both sides in the thickness direction, the temperature uniformity in the thickness direction is high, and the above Boeing phenomenon occurs. Excellent effect of suppressing. Further, from the viewpoint of further improving the effect of suppressing the occurrence of the Boeing 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, for example, the width of the heater 80 may be designed to be sufficiently larger than the length in the width direction of the F polymer.

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 It is preferably 70 ° C. or lower, more preferably 30 to 50 ° C. In this case, the temperature of the F polymer can be maintained sufficiently high up to the first cooling roll 30 while preventing deterioration of the F polymer. When the die temperature and the die lip temperature are different, X ¹ means the die temperature.
Further, when the temperature of the first cooling roll 30 was defined as ^{Y 1} [° C.], the difference ^(X 1 -Y ¹⁾ is preferably 250 ° C. or less, more preferably 200 ° C. or less, more preferably 125 ~ 175 ° C. .. In this case, since the degree of cooling of the F polymer by the first cooling roll 30 becomes more appropriate, distortion of MD and TD is unlikely to remain in the obtained film 1, and deformation due to insufficient cooling can be suitably prevented. Specifically, Y ¹ is preferably 150 to 250 ° C.

Further, from the viewpoint of further improving the effect of suppressing the occurrence of the Boeing phenomenon even during cooling by the first cooling roll 30, the first cooling roll 30 can make the temperatures of the F polymer in MD and TD uniform. It is preferable to configure.
Therefore, the first cooling roll 30 is preferably configured to have a mechanism for passing the heat medium, and preferably has a configuration having a double mechanism in which the heat medium reciprocates in the axial direction and repeatedly passes through. ^{The temperature Y 1} of the first cooling roll 30 means the temperature of the heat medium.

In the configuration shown in FIG. 3, a pair of heaters 80 are arranged, but only one of them may be arranged. Further, the non-contact heating unit may be configured by a blow device that blows hot air instead of the heater 80.

In all of the methods 1 to 3, the thickness of the F polymer in the molten state (thickness t in FIGS. 1 and 3) before contacting with the first cooling roll 30 is preferably 100 to 200 μm. In this case, the accuracy of heating by the heater 80 and cooling by the first cooling roll 30 is improved, and the distortion of MD and TD is less likely to remain in the obtained film 1.

When the ratio (draw ratio) of the opening degree of the lip 21 of the T die 20 to the thickness of the finally obtained film 1 is large, the molecular chain of the polymer contained in the F polymer is in a strongly stretched state, and the polymer molecules are formed. Easy to orient. As a result, the distortion of MD and TD remaining on the film 1 tends to increase. Therefore, the draw ratio is preferably 50 or less.
Further, the peripheral speed of the first cooling roll 30 (peripheral speed S in FIGS. 1 and 3) is more preferably 2 to 20 m / min from the viewpoint of further reducing the distortion of MD and TD remaining on the film 1. The temperature of the second cooling roll 40 is more preferably 30 to 90 ° C.

The F polymer (film 1) after being separated from the first cooling roll 30 may be subjected to a surface treatment capable of introducing an adhesive functional group on the surface thereof. Such surface treatments include corona discharge treatment, discharge treatment such as plasma treatment, plasma graft polymerization treatment, electron beam irradiation, light irradiation treatment such as excimer UV light irradiation, itro treatment using flame, and wet etching using metallic sodium. Processing can be mentioned.
By this surface treatment, polar functional groups such as a hydroxy group, a carbonyl group, and a carboxy group are introduced into the surface of the film 1, and as a result, the adhesiveness with other surfaces is further enhanced.

Hereinafter, the laminated body of the present invention (hereinafter, also referred to as “the present laminated body”) will be described.
The present laminate is a laminate in which an F polymer layer (a layer made of the film of the present invention) and a base material layer are laminated in this order. The present laminate is a method of laminating a film of the present invention and a film-like or sheet-like base material other than the film of the present invention by a roll-to-roll method, for example, at a melting temperature of an F polymer to 400 ° C. Alternatively, it is preferably obtained by a method of laminating and then hot-pressing the F polymer at a melting temperature of to 400 ° C.

Examples of the material of the base material layer in this laminate include metals and resins. Examples of the resin include a thermoplastic resin, a non-thermosetting resin, an uncured product of a curable resin, and a cured product of a curable resin. In particular, metals and heat-resistant resins are preferable.
The base material layer in the present laminate is preferably a layer formed from a film-like or sheet-like base material. As the film-shaped or sheet-shaped base material, a metal foil and a heat-resistant resin film are preferable.
The base material layer in the present laminate may also be a resin layer or a metal layer formed on the surface of the film of the present invention by means such as coating or plating.

When the base material layer in the present laminate is a layer formed of a metal foil, the ten-point average roughness of the surface of the metal foil is preferably 0.01 μm or more and 0.5 μm or less. In this case, the film of the present invention and the metal foil tend to adhere more firmly. Therefore, the electrical characteristics are likely to be remarkably exhibited in the laminate having the film of the present invention having high film thickness accuracy and the printed circuit board obtained by processing the laminate.
Specifically, when the base material layer in the present laminate is made of a metal foil, the dielectric loss tangent of the F polymer layer of the present 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, rolled copper foil and electrolytic copper foil are preferable.
The surface of the metal foil may be rust-proofed (formation of an oxide film such as chromate). Further, the surface of the metal foil may be treated with a silane coupling agent. The processing range at that time may be a part of the surface of the metal foil or the entire surface.
The thickness of the metal foil is preferably 0.1 to 20 μm, more preferably 0.5 to 10 μm.

Further, as the metal foil, a metal foil with a carrier containing two or more layers of metal foil may be used. The metal foil with a carrier includes a carrier copper foil (thickness: 10 to 35 μm) and an ultrathin copper foil (thickness: 2 to 5 μm) laminated on the carrier copper foil via a release layer. Copper foil can be mentioned. By using such a copper foil with a carrier, it is possible to form a fine pattern by an 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 layers are laminated are preferable.
Specific examples of the metal foil with a carrier include the trade name "FUTF-5DAF-2" manufactured by Fukuda Metal Leaf Powder Industry Co., Ltd.

The base material layer of this laminate may be a metal layer formed by a vapor phase film forming method and a plating method. The metal layer can be formed, for example, by 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 the metal from the seed layer by an electroplating method. The surface of the film of the present invention may be surface-treated before forming the seed layer. Examples of the surface treatment method include annealing treatment, 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.
Examples of the metal in the seed layer include copper, nickel, chromium, nichrome alloy, titanium alloy and the like.
Copper is mentioned as a metal to be plated by the electrolytic plating method.

When the base material layer in the present laminate is a layer of a heat-resistant resin film, such a film contains one or more kinds of heat-resistant resins, and may be a single-layer film or a multilayer film. Glass fiber, carbon fiber, or the like may be embedded in the heat-resistant resin film.
When the base material 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 base material 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 laminated body is remarkably lowered, and warpage is unlikely to occur.
Examples of the heat-resistant resin include polyimide, polyarylate, polysulfone, polyallylsulfone, aromatic polyamide, aromatic polyetheramide, polyphenylene sulfide, polyallyl ether ketone, polyamideimide, liquid crystal polyester, and liquid crystal polyester amide. Polyimide (particularly aromatic polyimide) is preferred.

In the present laminate which is a heat-resistant resin film having the film of the present invention on both sides, the thickness (total thickness) thereof is preferably 220 μm or more, more preferably 250 μm or more. The thickness is preferably 500 μm or less. In such a configuration, the ratio of the total thickness of the two F polymer layers to the thickness of the heat-resistant resin film is more preferably 0.8 or more. The above ratio is preferably 5 or less.
In this case, the characteristics of the heat-resistant resin film (high yield strength, resistance to plastic deformation) and the characteristics of the F polymer layer (low water absorption) are exhibited in a well-balanced manner.

Specific examples of the present 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 is mentioned.
A preferred embodiment of the laminate in which the base material layer is a heat-resistant resin film is a polyimide film having a heat-resistant resin film having a thickness of 20 to 100 μm, and the film of the present invention, the polyimide film, and the like. Examples thereof include a three-layer film in which the films of the present invention are directly contacted and laminated in this order. In such an embodiment, the thicknesses of the two films of the present invention are the same, preferably 100 to 200 μm. The total thickness ratio of the two films of the present invention to the thickness of the polyimide film is preferably 0.5 to 5. The laminated body of such an embodiment is most likely to exhibit the effect of the above-mentioned laminated body.

Here, the outermost surface of the present laminate (the surface of the F polymer layer opposite to the base material layer) may be further surface-treated in order to further improve its linear expansion property and adhesiveness.
Examples of the surface treatment method include annealing treatment, corona treatment, plasma treatment, ozone treatment, excimer treatment, and silane coupling treatment.
The conditions for the annealing treatment are preferably 120 to 180 ° C., a pressure of 0.005 to 0.015 MPa, and a time of 30 to 120 minutes.
Examples of the gas used for the plasma treatment include oxygen gas, nitrogen gas, rare gas (argon and the like), hydrogen gas, ammonia gas and vinyl acetate. One type of these gases may be used, or two or more types may be used in combination.

A printed circuit board is obtained by etching the metal foil of the present laminate (metal foil with F polymer layer) in which the base material layer is a metal foil to form a transmission circuit. Specifically, a method of etching a metal foil to process it into a predetermined transmission circuit, or a method of processing a metal foil into a predetermined transmission circuit by an electrolytic plating method (semi-additive method (SAP method), MSAP method, etc.). Can be used to manufacture printed circuit boards.
A printed circuit board manufactured from a metal foil with an F polymer layer has a transmission circuit formed from the metal foil and an F polymer layer in this order. Specific examples of the configuration of the printed circuit board include a transmission circuit / F polymer layer / prepreg layer, and a transmission circuit / F polymer layer / prepreg layer / F polymer layer / transmission circuit.
In the manufacture of 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 of the film of the present invention.

Although the film of the present invention, the method for producing the same, and the laminate of the present invention have been described above, the present invention is not limited to the configuration of the above-described embodiment.
For example, the film of the present invention and the laminate of the present invention may have any other configuration added or replaced with any configuration exhibiting the same function in the above-described configuration.
In addition, the production method of the present invention may additionally have any other step in the configuration of the above embodiment, or may be replaced with any step that produces the same action.

Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited thereto. Details of each component are shown below.
[F polymer]
F polymer 1: A 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 having no functional group containing 98.0 mol% and 2.0 mol% of TFE units and PPVE units in this order (melting temperature 300 ° C.).
The F polymer 1 has ^{1000 carbonyl group-containing groups per 1 × 10 6} main chain carbon atoms, and the F polymer 2 has 40 carbonyl group-containing groups.
[pellet]
Pellet 1: F polymer 1 pellet (diameter: 2.2 mm)
[Measurement of haze]
The haze (cloudiness) of the film 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 expansion and contraction rate]
According to JISK7133: 1999, a film was cut out to a size of 120 mm × 120 mm, and then a 100 mm marked line was drawn in the film flow direction (MD) and the width direction (TD), and the length of the marked line was measured. The film was allowed to stand in an oven at 180 ° C. and heated for 30 minutes, then naturally cooled to 25 ° C., the length of the marked line was measured again, and the expansion / contraction ratio was calculated according to the following formula.
Formula: {(length of marked line before heating)-(length of marked line after heating)} / (length of marked line before heating) x 100
[Film appearance]
The film was allowed to stand on a smooth glass surface, the presence or absence of warpage (waviness) was confirmed, and the film was evaluated according to the following criteria.
〇: No warpage is confirmed.
×: Warpage is confirmed.

[Example 1]
(1) Production of Film F Polymer 1 was put 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 molten F polymer 1 is sandwiched between the first cooling roll 30 at 200 ° C. by the quenching roll 301 which is a metal elastic roll controlled at 90 ° C., and then toward the first cooling roll. 1 From an air knife (height 50 mm) installed perpendicular to the tangent line in contact with the cooling roll, a slit-shaped air flow of 200 ° C. is uniformly blown linearly in the width direction of the first cooling roll 30 at a wind speed of 15 m / sec. Then, it was pressed against the first cooling roll 30, passed through the second cooling roll 40 at 90 ° C., and then taken up and wound up by the winding rolls 61 and 62 heated to 90 ° C. The haze of the obtained film (hereinafter referred to as PFA film 1) was 3%, and the thermal expansion / contraction rate after heating at 180 ° C. for 30 minutes was 0.2% for MD and −0.3% for TD.
A hopper is connected to the front stage of the kneading portion of the extruder, and when the F polymer 1 is charged, the pellet 1 is charged into the hopper and subjected to decompression treatment and heat treatment of 100 Pa or less in the hopper to perform the connection portion. The temperature of the F polymer in the above was adjusted to 180 ° C. Further, the molten F polymer 1 extruded from the T-die was heat-treated at 320 ° C. with a non-contact heater before coming into contact with the quenching roll and the first roll.
(2) Manufacture and Evaluation of Antenna Substrate A nickel-chromium alloy layer is formed on the PFA film 1 by a roll-to-roll method by sputtering a nickel-chromium alloy to a thickness of 10 nm, and then the nickel-chromium alloy is formed. A copper layer was formed on the layer by sputtering copper to a thickness of 200 nm. Further, a dry film resist was roll-laminated on the copper layer at 90 ° C., and then exposed and developed so that the mesh width was 6 μm.
The mesh portion was plated to a thickness of 6 μm by copper sulfate electrolytic copper plating. Then, 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 substrate was measured, and the evaluation of whether or not the antenna substrate was conducting was performed as conducting (◯) / not conducting (×). Further, the haze of the antenna substrate after forming the mesh antenna was measured by the above method.
Table 1 shows the film manufacturing conditions, film characteristics, and performance evaluation results as an antenna.

[Example 2]
A film was formed in the same manner as in (1) of Example 1 except that F polymer 2 was used instead of F polymer 1 and air was not blown onto the molten F polymer 2 by an air knife on the first cooling roll. Manufactured (PFA film 2). Using the obtained PFA film 2, an antenna substrate and an antenna were prepared in the same manner as in (2) of Example 1, and evaluated in the same manner. Table 1 shows the film manufacturing conditions, film characteristics, and performance evaluation results as an antenna.

[Example 3]
The F polymer 1 is extruded from the T die to a thickness of 125 μm, and the quenching roll 301 is not used (that is, the quenching roll 301 and the first cooling roll 30 are not sandwiched), and the first cooling roll is used. The film was produced in the same manner as in (1) of Example 1 except that the film was wound through the first cooling roll without air blowing the molten F polymer 1 with an air knife (1). PFA film 3). Using the obtained PFA film 3, an antenna substrate and an antenna were prepared in the same manner as in (2) of Example 1, and evaluated in the same manner.
Table 1 shows the film manufacturing conditions and film characteristics of the obtained PFA film 3 and the performance evaluation results as an antenna. The PFA film 3 had poor adhesion to the first cooling roll, and "air marks", which are marks of air entering 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 cover material for an antenna. Further, the film of the present invention can be easily processed into a metal laminated plate (metal foil with resin), and the obtained processed articles include transparent flexible printed circuit boards, antenna parts, printed circuit boards, sports equipment, food industry supplies, and the like. It can be applied to various fields such as flexible device devices, wearable devices that emphasize design, and medical devices.
The entire contents of the specification, claims, abstract and drawings of Japanese Patent Application No. 2020-062167 filed on March 31, 2020 are cited here as the disclosure of the specification of the present invention. It is something to incorporate.

1 ... film, 10,101 ... manufacturing equipment, 20 ... T die, 21 ... lip, 30 ... first cooling roll, 301 ... quenching roll, 40 ... second cooling roll, 50 ... take-up roll, 61, 62 ... transport Roll, 70 ... air knife, 80 ... heater, t ... thickness, S ... peripheral speed, 11 ... extrusion molding device, 2 ... hopper, 21 ... first stage, 211 ... heater, 212 ... connection, P1 ... pump , 22 ... 2nd stage, 221 ... heater, 222 ... connection, P2 ... pump, 3 ... kneading, 31 ... cylinder, 311 ... tip opening, 32 ... screw, 33 ... gearbox, 331 ... rotating shaft, 34 ... motor, 341 ... rotating shaft, 35 ... heater, 5 ... T die, 6 ... stationary mixer, L ... total length, D ... diameter

Claims

An extruded film composed of a tetrafluoroethylene polymer, having a thickness of 100 to 200 μm, a haze of 8% or less, and a thermal expansion / contraction rate after heating at 180 ° C. for 30 minutes in the flow direction of the film. A film that is -1 to + 1% in both the width direction and the width direction.
The film according to claim 1, wherein the tetrafluoroethylene-based polymer is a tetrafluoroethylene-based polymer containing a unit based on tetrafluoroethylene and a unit based on perfluoro (alkyl vinyl ether).
The tetrafluoroethylene-based polymer contains a unit based on perfluoro (alkyl vinyl ether) and has a polar functional group, or a tetrafluoroethylene-based polymer having a polar functional group, or 2.0 to 2.0 to all units based on perfluoro (alkyl vinyl ether). The film according to claim 1 or 2, which is a tetrafluoroethylene-based polymer containing 5.0 mol% and having no polar functional group.
The film according to any one of claims 1 to 3, wherein the melting temperature of the tetrafluoroethylene polymer is 260 to 320 ° C.
The film according to any one of claims 1 to 4 is produced by a T-die casting method, in which the tetrafluoroethylene polymer is discharged from a die in a molten state and extruded to control the temperature. A manufacturing method comprising the operation of sandwiching a film between two rolls and cooling the film.
The manufacturing method according to claim 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.
An extrusion molding apparatus having a kneading portion and a hopper connected to the kneading portion is provided, and pellets of a tetrafluoroethylene-based polymer having a melting temperature of 260 to 320 ° C. are charged into the hopper, and the kneading portion is used for melting and kneading. When the melt-kneaded product was discharged from the T-die to produce a film, the temperature of the pellet at the connection portion of the hopper with the kneaded portion was set to (the melt temperature −200) to (the melt temperature −100) ° C. The production method according to claim 5 or 6, further comprising an operation of supplying the pellets to the kneading portion after adjusting to the range of.
The production method according to any one of claims 5 to 7, wherein the pellet has a diameter of 1.0 to 4.0 mm.
The method according to any one of claims 5 to 8, wherein the hopper is a multi-stage hopper including a first-stage portion and a second-stage portion arranged on the kneading portion side from the first-stage portion. Manufacturing method.
The manufacturing method according to any one of claims 5 to 9, wherein the pressure in the step portion of the hopper closest to the kneading portion is 1000 Pa or less.
A claim that the extrusion molding apparatus includes a T-die connected to the side opposite to the hopper in the axial direction of the kneading portion, and a stationary mixer provided between the kneading portion and the T-die. The production method according to any one of 5 to 10.
The claim further comprises the operation of discharging the tetrafluoroethylene-based polymer from the T-die in a molten state and heating the molten tetrafluoroethylene-based polymer in a non-contact heating unit before contacting with the first cooling roll. The production method according to any one of 5 to 11.
The production method according to claim 12, wherein the difference between the temperature of the tetrafluoroethylene polymer and the temperature of the first cooling roll in the T-die is 250 ° C. or less.
The production method according to claim 12 or 13, wherein the absolute value of the difference between the temperature of the tetrafluoroethylene polymer and the temperature of the non-contact heating unit in the T-die is 70 ° C. or less.
A laminate having a layer made of the film according to any one of claims 1 to 4 and a base material layer made of a base material other than the film.