TW202146479A - Fluororesin film and manufacturing method for same - Google Patents

Abstract

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

Description

Fluorine resin film and method for producing the same

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

With the development of light weight and miniaturization of electronic equipment, flexible printed wiring boards (FPC) are widely used as light-weight and flexible wiring materials in order to cope with the limitation of wiring quantity or space in the equipment. In recent years, the transmission signal in the printed wiring board has become increasingly high-speed, and the signal has also increased in frequency. Along with this, low dielectric properties (low dielectric constant, low dielectric loss factor) in the high frequency region are strongly required for FPC. In response to this requirement, it is proposed to use the following substrate film as the substrate film for FPC. Sulfide (PPS) or the like is constituted in place of the conventional polyimide (PI) and polyethylene terephthalate (PET). On the other hand, with the continuous pursuit of improving the design of electronic equipment, flexible devices such as flexible displays and touch panels, or semiconductor components such as LEDs (Light Emitting Diodes) are used for reflow. Electronic machines, etc. are increasingly using FPC in visible parts. In such electronic devices, etc., the FPC needs to have both transparency.

Although PI film is excellent in heat resistance, it has a problem in transparency. Although PET film has excellent transparency, it has low heat resistance, and when it is used in a flexible printed wiring board, there is a problem that the substrate is warped or dimensionally changed due to the heat during reflow. Tetrafluoroethylene polymers such as polytetrafluoroethylene (PTFE) have high transparency and excellent physical properties such as chemical resistance, water and oil repellency, heat resistance, and electrical properties, and are compatible with PI, LCP, SPS, PPS and other materials. In comparison, the dielectric constant and the dielectric loss factor are also low, so it can be used as the base film of FPC which is transparent and excellent in reflow resistance. On the other hand, tetrafluoroethylene-based polymers have poor dimensional stability and are prone to positional displacement during circuit processing. Therefore, Patent Document 1 proposes a method of removing the strain by annealing treatment (heat treatment) after film formation. prior art literature Patent Literature

Patent Document 1: International Publication No. 2019/203243

[Problems to be Solved by Invention]

The tetrafluoroethylene-based polymer has crystallinity, and its crystals tend to grow during the cooling process of the melt-molded body. Therefore, even if the light transmittance of the obtained film is high, the haze tends to increase. In addition, when the film becomes thick, even if heat treatment is performed by the method of Patent Document 1, it is difficult to relieve the strain and the dimensional stability is deteriorated. Therefore, the flatness of the film may be impaired by the heat treatment.

The inventors of the present invention have conducted intensive research, and as a result, have found a film that has good dimensional stability, low haze, good yield in circuit formation, and can achieve both transparency and heat resistance. An object of the present invention is to provide a film having the above-mentioned properties and a method for producing the same. [Technical means to solve problems]

The present invention has the following aspects. <1> A film, which is an extrusion-molded film composed of a tetrafluoroethylene-based polymer, the thickness of which is 100 to 200 μm, the haze is 8% or less, and the thermal expansion ratio after heating at 180°C for 30 minutes is the same as the film. The travel direction and the width direction are both -1 to +1%. <2> The film according to <1>, wherein the tetrafluoroethylene-based polymer includes a tetrafluoroethylene-based unit and a perfluoro(alkyl vinyl ether)-based unit. <3> The film according to <1> or <2>, wherein the tetrafluoroethylene-based polymer contains a perfluoro(alkyl vinyl ether)-based unit and has a polar functional group, or contains 2.0 to 5.0 with respect to all units Molar % of units based on perfluoro(alkyl vinyl ether) and without polar functional groups. <4> The film according to any one of <1> to <3>, wherein the melting temperature of the tetrafluoroethylene-based polymer is 260 to 320°C.

<5> A method for producing the film according to any one of the above <1> to <4>, which is a method for producing the film according to any one of the above <1> to <4> by a T-die casting method , which includes the following operations: the above-mentioned tetrafluoroethylene-based polymer is extruded from a die in a molten state and extruded, and the obtained film is sandwiched between two temperature-controlled rolls and cooled. <6> The manufacturing method according to <5>, wherein the temperature of one of the two rolls subject to temperature control is 150 to 250°C, and the temperature of the other is 80 to 150°C. <7> The production method according to <5> or <6>, comprising an extrusion molding apparatus having a kneading section and a hopper connected to the kneading section, and feeding tetrafluoroethylene having a melting temperature of 260 to 320° C. into the hopper When the pellets of the vinyl polymer are melted and kneaded by the above-mentioned kneading section and the melt-kneaded product is discharged from the T-die to produce a film, the following operation is further included: After the temperature is adjusted within the range of (the above-mentioned melting temperature-200) to (the above-mentioned melting temperature-100)° C., the above-mentioned pellets are supplied to the above-mentioned kneading section. <8> The production method according to any one of <5> to <7>, wherein the diameter of the particles is 1.0 to 4.0 mm.

<9> The manufacturing method according to any one of <5> to <8>, wherein the hopper is provided with a first stage portion and a second stage portion arranged on the side of the kneading portion with respect to the first stage portion. Multi-stage hopper. <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 production method according to any one of <5> to <10>, wherein the extrusion molding apparatus includes: a T die connected to the kneading section on the opposite side of the hopper in the axial direction; and a static mixer A device is arranged between the above-mentioned kneading part and the above-mentioned T-die. <12> The production method according to any one of <5> to <11>, further comprising an operation of discharging the tetrafluoroethylene-based polymer in a molten state from a T-die, and treating the tetrafluoroethylene-based polymer in a molten state The polymer is heated with a non-contact heating section before it contacts the first chill roll. <13> The production method according to <12>, wherein the difference between the temperature of the tetrafluoroethylene-based polymer in the T-die and the temperature of the first cooling roll is 250°C or less. <14> The production method according to <12> or <13>, wherein the absolute value of the difference between the temperature of the tetrafluoroethylene-based polymer in the T-die and the temperature of the non-contact heating portion is 70°C or less.

<15> A layered body having a layer composed of the film according to any one of the above <1> to <4>, and a base material layer composed of a base material other than the film. [Effect of invention]

According to the present invention, there is provided a film with good dimensional stability, low haze, good yield in circuit formation, and both transparency and heat resistance, and a manufacturing method thereof. According to the present invention, in particular, a relatively thick film of about 100 μm, preferably as a base material of an antenna substrate, can be provided. The film of the present invention can be used as a colorless, transparent and low-loss antenna substrate.

The following terms have the following meanings. "Film thickness" is obtained by measuring the thickness of the film at 10 points in the width direction at equal distances using a contact thickness gauge DG-525H (manufactured by Ono Shoki Co., Ltd.) and a probe AA-026 (ϕ10 mm, SR7). The average of the measured values. The "melting temperature of the polymer" is the temperature corresponding to the maximum value of the melting peak measured by differential scanning calorimetry (DSC). The "unit" in the polymer means an atomic group based on 1 molecule of the above-mentioned monomer formed by the polymerization of the monomer. The unit may be a unit directly formed by a polymerization reaction, or a unit in which a part of the above-mentioned unit is converted into another structure by treating the polymer. Hereinafter, the unit based on the monomer a is also abbreviated as "monomer a unit". The "glass transition point of the polymer" is the value determined by analyzing the 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"), with a thickness of 100-200 μm, a haze of 8% or less, and heated at 180°C for 30 The thermal expansion and contraction rate after one minute is -1 to +1% in both the advancing 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 also be a roll film in a wound state. Moreover, as the laminated body of this invention which has the layer which consists of the film of this invention and the base material layer which consists of a base material other than the film of this invention, the laminated body which laminated|stacked the film of this invention and a metal foil is preferable. Such a laminate formed by laminating the film and metal foil of the present invention can be suitably used as an FPC if it is cut to a specific length and the metal foil is processed into a transmission circuit (including vias). For example, it is suitable for use as an antenna substrate that is colorless and transparent and has excellent electrical properties. Furthermore, the layer composed of the film of the present invention is hereinafter referred to as "F polymer layer", and the substrate layer composed of substrates other than the film of the present invention is hereinafter referred to as "substrate" unless otherwise specified. Floor".

Forming strain caused by this production method (melt forming method by extrusion forming) remains in a film of a normal hot-melt fluororesin. Regarding the film of the present invention, by appropriately controlling the cooling conditions of the resin film during molding as described below, both MD and TD have a thermal expansion and contraction ratio of -1 to +1%, and the strain in each direction is small and sufficient Even if the thickness is 100 to 200 μm, the haze is 8% or less, and the transparency is excellent. Therefore, since the laminated body having this film layer has small strain and is sufficiently uniform, it is considered that it is excellent in thermal shock resistance, suppresses deformation, and is excellent in dimensional stability. For example, when the laminate of the present invention using metal foil as the base layer is processed into a printed wiring board, the thermal shock resistance when forming through holes or through holes is high, and as a result, it is easy to obtain a product that is less prone to breakage. printed wiring board.

In addition, the thermal expansion-contraction rate of a film was measured as follows. First, a test piece having a square of 12 cm square along both sides of the MD and along the two sides of the TD was cut out of the film. Next, on the surface of the obtained test piece, a line segment with a length of 10 cm is drawn along MD and TD, respectively. Then, the test piece was heated in an oven at 180° C. for 30 minutes, taken out, cooled to 25° C. naturally, and then the length of the line segment was measured again. The thermal expansion ratio is 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 and contraction rate is the change rate (percentage) of the segment length before and after heating. In addition, a negative number represents film elongation, and a positive number represents film shrinkage. The thermal expansion ratio 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%, respectively, and more preferably -0.5 to +0.5%. When the thermal expansion ratio is within the above range, even if it is heated, it becomes more difficult to generate wrinkles due to the strain of the film.

The F polymer in the present invention is a polymer comprising tetrafluoroethylene (TFE) based units (TFE units). The F polymer in the present invention is hot-melt, and its melting temperature is preferably 260-320°C, more preferably 275-315°C, and still more preferably 290-310°C. In this case, the formability 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.

As the F polymer, polytetrafluoroethylene (PTFE), a polymer (PFA) containing a TFE unit and a unit (PAVE unit) based on a perfluoro(alkyl vinyl ether) (PAVE), a hexafluoro-based A polymer (FEP) of units of propylene (HFP), preferably PFA. As PAVE, CF ₂ =CFOCF ₃ , CF ₂ =CFOCF ₂ CF _{3 ,} and CF ₂ =CFOCF ₂ CF ₂ CF ₃ (PPVE) are preferred, and PPVE is more preferred.

The F polymer preferably has polar functional groups. The polar functional group may be included in the unit of the F polymer, and may also be included in the terminal group of the main chain of the F polymer. Examples of the latter form include a polymerization initiator, an F polymer having a polar functional group as a terminal group derived from a chain transfer agent or the like, and a polar functional polymer obtained by subjecting the F polymer to plasma treatment or ionizing radiation treatment. base F polymer. As the polar functional group, a hydroxyl group-containing group and a carbonyl group-containing group are preferable. As a group containing a hydroxyl 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 as the carbonyl group-containing group, a carboxyl group, an alkoxycarbonyl group, an amide group, an isocyanate group, a carbamate group (-OC(O) are preferred. )NH ₂ ), acid anhydride residues (-C(O)OC(O)-), imide residues (-C(O)NHC(O)- etc.) and carbonate groups (-OC(O)O -), more preferably an acid anhydride residue.

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

The F polymer is preferably a polymer (1) and a polymer (2), wherein the polymer (1) includes a TFE unit and a PAVE unit and has a polar functional group, and the polymer (2) includes a TFE unit and a PAVE unit , and the content of PAVE units is 2.0 to 5.0 mol % relative to all units, and it does not have polar functional groups. These F polymers are easy to form fine spherulites in the molded product, and it is easy to improve the adhesion with other components. As a result, it becomes easier to obtain a molded product excellent in surface smoothness, adhesiveness, and electrical properties.

The polymer (1) is preferably a polymer containing a TFE unit, a PAVE unit and a unit based on a monomer having a polar functional group, more preferably a TFE unit of 90 to 99 mol %, 0.5 to 99 mol % of the total unit. 9.97 mol % of PAVE units, 0.01-3 mol % of units based on monomers with polar functional groups. In addition, as the monomer having a polar functional group, itaconic anhydride, citraconic anhydride, and 5-norbornene-2,3-dicarboxylic anhydride (hereinafter, also referred to as "NAH") are preferred. As a specific example of the polymer (1), the polymer described in International Publication No. 2018/16644 can be mentioned.

The polymer (2) preferably contains 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 units. The content of the PAVE units in the polymer (2) is preferably 2.1 to 5.0 mol %, more preferably 2.2 to 5.0 mol %, based on the total units. Furthermore, the fact that the polymer (2) does not have polar functional groups means that the number of polar functional groups contained in the polymer is less than 500 with respect to the number of carbon atoms constituting the main chain of the polymer, 1×10 ^{6 .} The number of the above-mentioned polar functional groups is preferably 100 or less, more preferably less than 50. The lower limit of the number of the above-mentioned polar functional groups is usually zero. The polymer (2) can be produced by using a polymerization initiator or a chain transfer agent that does not generate polar functional groups as the terminal groups of the polymer chain, and can also be used for F polymers with polar functional groups (in the main polymer of the polymer). The terminal group of the chain has a polar functional group derived from a polymerization initiator, such as an F polymer, etc.), and is produced by fluorination treatment. As a method of the fluorination treatment, a method using a fluorine gas can be mentioned (refer to Japanese Patent Laid-Open No. 2019-194314, etc.).

The films of the present invention may contain other resins than F polymers. However, the content of the F polymer contained in the film is preferably 80% by mass or more, and more preferably 100% by mass. Examples of other resins other than the F polymer include epoxy resins, polyimide resins, polyimide as precursors of polyimide, acrylic resins, phenolic resins, liquid crystalline polyester resins, polyimide resins, and polyimide resins. Olefin resin, modified polyphenylene ether resin, polyfunctional cyanate resin, polyfunctional maleimide-cyanate resin, polyfunctional maleimide resin, vinyl ester resin, urea resin, phthalate Diallyl formate resin, melamine resin, guanamine resin, melamine-urea co-condensation resin, styrene resin, polycarbonate resin, polyarylate resin, polyarylene, polyarylene, aromatic polyamide resin, aromatic Polyetheramide, polyphenylene sulfide, polyaryletherketone, polyamideimide, polyphenylene ether.

The film of the present invention may further contain, for example, an inorganic filler, an organic filler, a thixotropy imparting agent, an antifoaming agent, a silane coupling agent, a dehydrating agent, a plasticizer, a weathering agent, an antioxidant, a heat stabilizer, a lubricant, and an antistatic agent. Agents, brighteners, colorants, conductive agents, mold release agents, surface treatment agents, viscosity modifiers, flame retardants, etc.

As inorganic fillers, boron nitride fillers, beryllium oxide fillers (fillers of beryllium oxides), silicate fillers (silicon oxide fillers, wollastonite fillers, talc fillers) and metal oxides (cerium oxide, oxide Aluminum, magnesium oxide, zinc oxide, titanium oxide, etc.) fillers. Moreover, at least a part of the surface of an inorganic filler may be surface-treated. As the surface treatment agent used for the surface treatment, polyols, saturated fatty acids, esters thereof, amines, paraffins, silane coupling agents, silicones, and polysiloxanes may, for example, be mentioned. The shape of the inorganic filler can be any of granular, needle-like (fibrous), plate-like, and the like, and specific shapes include spherical, scaly, lamellar, leaf-like, almond-like, and columnar shapes. , cockscomb, equiaxed, leaf, mica, block, plate, wedge, rosette, reticulate, angular column.

Hereinafter, the manufacturing method of the film of this invention is demonstrated. In order to be able to adjust the strain of the film, the film of the present invention can be suitably produced by a T-die casting method (melt extrusion method using a T-die). The present inventors have found that the strain of MD and TD of the film caused by the T-die casting method depends on the state (temperature, fluidity) and cooling conditions of the F polymer in the molten state. The state until the F polymer is crystallized by the cooling roll is determined. In other words, the present inventors have found that if the state of the F polymer and the cooling conditions are appropriately set to control the crystallization of the F polymer, the thermal shrinkage (strain) of the MD and TD of the obtained film can be obtained. Condensed within a specific range, and due to the suppression of crystal growth, even a relatively thick film such as 100 to 200 μm can achieve low haze.

The production method of the film of the present invention includes the following operations: the F polymer is extruded from a T die in a molten state, and the resulting film is sandwiched between two temperature-controlled rolls and cooled (this method 1) . The temperature of one of the above-mentioned two rolls subject to temperature control is preferably 150 to 250°C, and the temperature of the other is 80 to 150°C. Furthermore, one of the two temperature-controlled rolls is preferably 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 diagram showing an embodiment of a film manufacturing apparatus used in the present method 1. FIG. The manufacturing apparatus 10 shown in FIG. 1 includes a T-die 20 , a first cooling roll (first cooling roll) 30 arranged vertically below the T-die 20 , a quenching roll 301 , and a second cooling roll 30 arranged in parallel with the first cooling roll 30 . The cooling roll 40 , the winding roll 50 that winds up the film 1 , and the conveying rolls 61 and 62 arranged between the winding roll 50 and the second cooling roll 40 . Moreover, the 1st cooling roll 30 may further be equipped with the air knife 70, Preferably it is equipped with the air knife 70.

The F polymer is heated and melted in an extruder (not shown) connected to the T die 20 , and then fed into the T die 20 . The molten F polymer is discharged toward the first cooling roll 30 from the die lip 21 of the T die 20 . Then, the molten F polymer discharged is brought into contact with the first cooling roll 30, and the F polymer is sandwiched between the first cooling roll 30 by the quench roll 301 and cooled. Furthermore, the F polymer is conveyed by the conveyance rollers 61 and 62 after passing through the second cooling roll 40 . After that, the F polymer is wound up to the winding roll 50 as the film 1 . As the first cooling roll 30, a metal roll capable of temperature control is preferably used, and as the quench roll 301, a metal elastic roll is preferably used.

As a metal elastic roll, the surface consists of a metal material, such as stainless steel, and the elastic material, such as fluid or rubber, is filled between the surface metal material and the shaft roll. The metal elastic roll includes, for example, a shaft roll that has a substantially cylindrical shape and is rotatably provided, and a metal thin film that is arranged so as to cover the outer peripheral surface of the shaft roll, has a cylindrical shape, and contacts the shaft as a film. a roll; and a fluid enclosed between the shaft roll and the metal film. The metal elastic roller exhibits elasticity by the above-mentioned fluid, and has the characteristic of being able to perform roll forming at low linear pressure. This characteristic is effectively utilized in the present invention to help control the film cooling conditions. As the material of the shaft roll, stainless steel can be exemplified. The metal thin film is preferably formed of stainless steel and has a thickness of 2 to 5 mm. The metal film preferably has bendability or flexibility, and preferably has a seamless structure without a welded joint. The metal elastic roll provided with such a metal film is excellent in durability, and when the metal film is mirror-finished, the same operation as a normal mirror-finished roll can be performed. In order to obtain a film with excellent surface smoothness, it is more preferable to make the surface of the metal elastic roll a mirror 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 Industry Co., Ltd. are mentioned.

The F polymer in the molten state is cooled by sandwiching it with a quenching roll 301, which is preferably a metal elastic roll, and a first cooling roll 30, which is preferably a metal roll, thereby cooling the film rapidly and suppressing the growth of crystals, thereby reducing fog. degree, and reduce the accumulation of strain in the film sandwiched between the first cooling roll and the quenching roll. The temperature of the first cooling roll 30 is preferably 150 to 250°C, and the temperature of the quench roll 301 is preferably 80 to 150°C so that the film can be rapidly cooled. Further, it is preferable that the first cooling roll and the quenching roll have a mechanism for passing the heat medium, and it is preferable to have a duplex mechanism for the heating medium to go back and forth in the axial direction and to pass through it repeatedly. The temperature of the first cooling roll and the temperature of the quenching roll refer to the temperature of the heat medium. When the quench roll is a metal elastic roll, it is preferably a temperature range that does not impair the properties of the metal elastic roll itself.

In this method 1, it is preferable to further provide the air knife 70 just behind the position of the 1st cooling roll 30 which clamps the F polymer in a molten state by the quench roll 301. The air knife 70 has a function of blowing a slit-shaped air stream uniformly and linearly along the width direction of the first cooling roll 30 from the slit nozzle to the line where the molten F polymer is in contact with the first cooling roll 30 , and the F polymer in the molten state is cooled and pressed against the first cooling roll 30 . Similar to the quench roll 301, it has the effect of improving the cooling efficiency of the F polymer, suppressing the haze of the obtained film, and reducing the thermal expansion and contraction rate. The temperature of the air blown out from the air knife is preferably 150-200°C, more preferably 170-200°C. If it is 150 degreeC or more, the thermal expansion-contraction rate of a film becomes small, and if it is 200 degreeC or less, haze tends to become small. The flow velocity of the air blown out from the air knife is preferably 10-20 m/sec.

The method for producing the film of the present invention further includes the following method: in the method 1, for example, using the extrusion molding apparatus 11 shown in FIG. 2). FIG. 2 is a conceptual diagram showing an embodiment of the extrusion molding apparatus used in the second method. In addition, in the following description, the right side in FIG. 2 (forward in the transfer direction of the melt-kneaded product) is referred to as a "front end", and the left side (rearward in the transfer direction described above) is referred to as a "base end".

The extrusion molding apparatus 11 shown in FIG. 2 includes a hopper 2 and a kneading section 3 communicating with the hopper 2 . The kneading section 3 of the present embodiment is composed of a uniaxial kneader having a cylinder 31 and a single screw 32 rotatably provided in the cylinder 31 . When a uniaxial kneader is used, it is easy to prevent the deterioration of the F polymer when the pellets are melt-kneaded. 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) expressed as the ratio of the overall length L to the diameter D is more preferably: 30 to 45. When the effective length is within the above-mentioned range, the deterioration of the F polymer can be prevented, and sufficient shear stress can be imparted to the F polymer, and the temperature unevenness of the melt-kneaded product can be easily reduced.

On the base end side of the cylinder 31, a gear box 33 and a motor 34 are arranged in this order. A gear (not shown) is connected to the front end of the rotating shaft 341 of the motor 34 , and the gear meshes with a specific gear (not shown) in the gear box 33 . In the gear box 33 , the rotational motion of the rotating shaft 341 is accelerated or decelerated and transmitted to the rotating shaft 331 . The front end 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, and the screw 32 is rotated at a predetermined rotational speed. As a result, the melt-kneaded product is transferred from the proximal end side (left side) toward the distal end side (right side) in FIG. 2 .

Further, a heater 35 is provided on the outer peripheral portion of the cylinder 31 . The pellets (F polymer) fed into the cylinder 31 are melted by the heating of the heater 35, mixed (kneaded) by the rotation of the screw 32, and transferred toward the front end side. Thereby, the pellets are melted and kneaded, and the melt-kneaded product is extruded from the front end opening 311 of the cylinder 31 . A T die 5 is arranged on the front end side of the cylinder 31 (the side opposite to the hopper 2 in the axial direction of the kneading portion 3). The melt-kneaded product extruded from the front end 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 this method 1, a film of the F polymer is produced. Here, the T-mode 5 in FIG. 2 only needs to be understood as corresponding to the T-mode 20 in FIG. 1 (or FIG. 3 described below). In addition, although not shown in figure, a heater is also provided in the T-die 5 .

In the present embodiment, a static mixer (static mixer) 6 is provided between the cylinder 31 (kneading unit 3 ) and the T-die 5 . The static mixer 6 divides, switches, or reverses the flow path of the melt-kneaded product to stir the melt-kneaded product. By providing such a static mixer 6, the melt-kneaded product can be uniformly kneaded while suppressing deterioration of the melt-kneaded product without applying excessive external force.

The hopper 2 is arranged on the base end side of the cylinder 31 . The hopper 2 of the present embodiment is composed of a two-stage hopper having a funnel-shaped first-stage portion 21 and a funnel-shaped second-stage portion 22 disposed on the side of the kneading portion 3 (cylinder 31 ) rather than the first stage portion 21 . constitute. The heater 211 and the pump P1 are connected to the first stage portion 21 . Thereby, the pellets supplied into the first stage portion 21 can be heated in a decompressed state. The first step portion 21 is connected to the second step portion 22 via the connection portion 212 . The heater 221 and the pump P2 are connected to the second stage portion 22 . Thereby, the pellets supplied into the second stage portion 22 can be heated in a decompressed state. The second step portion 22 is connected to the cylinder 31 via the connection portion 222 . The inner surface (inner peripheral surface) of the hopper 2 (the first step portion 21 and the second step portion 22 ) is preferably covered with a resin film. That is, the inner surface of the hopper 2 is preferably resin lined. Thereby, the softened particles can be sufficiently prevented from adhering to the inner surface of the hopper 2 . In addition, as a constituent material of the resin film, a fluororesin such as PTFE may, for example, be mentioned.

The particles used in this method 2 may contain components 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. As components other than the F polymer, the above-mentioned other resins or additives can be exemplified. Moreover, as a shape of a particle, a spherical shape and a cylindrical shape are mentioned, Preferably it is a cylindrical shape. The diameter of the particles is preferably 1.0 to 4.0 mm. If it is a particle of this diameter, bridging (clogging) in the hopper 2 can be prevented, and when heating in the hopper 2, the heating (warming) can be sufficiently performed to the inside thereof.

In the present method 2, the pellets of the F polymer are preheated in the hopper 2, then supplied to the kneading section 3, melted and kneaded in the kneading section 3, and the obtained melt-kneaded product is discharged from the T-die 5 to produce a film . At this time, the temperature of the pellets in the connection part 222 of the hopper 2 and the kneading part 3 is adjusted in the range of (X-200)-(X-100) degreeC. Furthermore, X is the melting temperature of the F polymer. The temperature of the particles in the connection part 222 of the hopper 2 and the kneading part 3 is preferably (X-175) to (X-125)°C. The temperature of the specific particles is preferably 70-225°C, more preferably 105-195°C. In this case, it is difficult to generate bridges in the hopper 2 due to the softening of the particles. Moreover, since the temperature unevenness of the melt-kneaded material in the kneading section 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 part 22 (the stage part closest to the kneading part 3 ) is preferably lower than the pressure in the first stage part 21 , preferably 1000 Pa or less, more preferably 100 Pa or less. Thereby, the air in the pellets can be sufficiently removed, and the formation of a heat insulating layer by the air can be prevented, and the occurrence of temperature unevenness in the melt-kneaded product in the kneading section 3 can be easily prevented. The softened granules are supplied to the kneading section 3 . The rotational speed of the screw 32 is preferably 10-50 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-mentioned conditions, a homogeneous melt-kneaded product with less temperature unevenness can be easily formed. As a result, the film of the present invention is easier to obtain. The melt-kneaded product is supplied to the T-die 5 via the static mixer 6 and discharged from the T-die 5 . The melt-kneaded material discharged from the T-die 5 is formed into a film as described in this method 1, and is wound up on a winding roll. Moreover, the extrusion molding apparatus 11 may have a cutter as needed.

According to the present method 2, the surging phenomenon is highly suppressed, and the polymer is uniformly melted and kneaded without imparting an excessive thermal history, thereby forming a film. Therefore, a wide-width film with few defects (fish eyes) and a sufficient length in the short-side direction can be easily produced. 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.

The production method of the film of the present invention further includes the following method: in the method 1 or the method 2, the F polymer is discharged from the T die in a molten state, and the molten F polymer is in a state before it contacts the first cooling roll. Heating is performed by a non-contact heating unit (this method 3). FIG. 3 is a schematic diagram showing an embodiment of the film manufacturing apparatus used in the present method 3. FIG. The manufacturing apparatus 101 shown in FIG. 3 is in the manufacturing apparatus 10 in the present method 1, and further has a pair of heaters (non-contact heating part) 80 arranged oppositely between the T-die 20 and the first cooling roll 30 , except that it is the same as the manufacturing apparatus 10 .

The F polymer is heated and melted in an extruder (not shown) connected to the T die 20 , and then fed into the T die 20 . The molten F polymer is discharged toward the first cooling roll 30 from the die lip 21 of the T die 20 . Then, the molten F polymer discharged is heated without contacting the heater 80 while passing between the pair of heaters 80 , and then contacts the first cooling roll 30 and is heated by the quenching roll 301 . It is cooled by being pressed against the first cooling roll 30 . At this time, the F polymer in the molten state can also be cooled and pressed by the air knife 70 provided in the following manner, and the slit-shaped air flow can be uniformly blown linearly along the width direction of the first cooling roll 30 . Abutting against the first cooling roll 30 , the air knife 70 is provided along a direction perpendicular to the tangent line contacting the first cooling roll 30 . Furthermore, after passing through the 2nd cooling roll 40, the F polymer is conveyed by the conveyance rolls 61 and 62, and is wound up by the winding roll 50 as the film 1.

According to this configuration, the F polymer in the molten state discharged from the T-die 20 is also maintained at a relatively high temperature by heating by the heater 80 until it reaches the first cooling roll 30 . Therefore, the F polymer in the molten state flowing down toward the first cooling roll 30 maintains relatively high fluidity, and thus does not easily become stretched by its own weight or the tensile force of the first cooling roll 30 . As a result, the phenomenon of bowing (the alignment of the F polymer in MD and TD) during film formation of the F polymer in the molten state is suppressed, and it is presumed that the above-mentioned strains in MD and TD (thermal expansion and contraction) can be obtained. rate) smaller films.

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 uniformity of the temperature in the thickness direction is high, and the The above-mentioned bending phenomenon produces an excellent effect. In addition, in order to further enhance the effect of suppressing the occurrence of the bending phenomenon, it is preferable to configure the heater 80 so that the temperature of the F polymer in the width direction can also be made uniform. In this case, for example, the width of the heater 80 may be designed to be sufficiently longer 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 preferably It is 70 degreeC or less, More preferably, it is 30-50 degreeC. In this case, the deterioration of the F polymer can be prevented, and the temperature of the F polymer can be maintained high enough until it reaches the first cooling roll 30 . Furthermore, when the die temperature is different from the die lip temperature, X ¹ refers to the die temperature. 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 lower, more preferably 200° C. or lower, and still more preferably 125 to 175° C. In this case, since the degree of cooling of the F polymer by the first cooling roll 30 is more appropriate, the obtained film 1 is less likely to remain in MD and TD strains, and deformation due to insufficient cooling can also be appropriately prevented. Specifically, Y ^{1 is} preferably 150 to 250°C.

Furthermore, in order to further enhance the effect of suppressing the occurrence of the warping phenomenon, it is preferable to configure the first cooling roll 30 so that the temperature in the MD and TD of the F polymer can be made uniform even when the first cooling roll 30 is used for cooling. Therefore, it is preferable that the 1st cooling roll 30 is comprised so that it may have the mechanism which passes a heat medium, and it is preferable that it is comprised so that it may be comprised with the double-type mechanism which reciprocates and passes the heat medium in the axial direction. Furthermore, the temperature of the first cooling roll 30 Y ¹ means the temperature of the heat medium.

In addition, in the structure shown in FIG. 3, a pair of heater 80 is arrange|positioned, but only one of them may be arrange|positioned. In addition, the non-contact heating part may be constituted by a blower device for blowing hot air instead of the heater 80 .

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

If the ratio (stretch ratio) of the opening degree of the die lip 21 of the T die 20 to the thickness of the film 1 finally obtained is large, the molecular chain of the polymer contained in the F polymer will be in a state with a large degree of extension, Polymer molecules are easily aligned. As a result, the strains of MD and TD remaining in the film 1 tend to be large. Therefore, the draw ratio is preferably 50 or less. Moreover, in order to further reduce the strain of MD and TD remaining in the film 1, the peripheral speed of the first cooling roll 30 (in FIGS. 1 and 3, the peripheral speed S) is also more preferably 2 to 20 m/min. Furthermore, the temperature of the second cooling roll 40 is more preferably 30 to 90°C.

The F polymer (film 1) after leaving|separated from the 1st cooling roll 30 can also be surface-treated so that an adhesive functional group can be introduce|transduced into the surface. Examples of the surface treatment include corona discharge treatment, discharge treatment such as plasma treatment, plasma graft polymerization treatment, electron beam irradiation, light irradiation treatment such as excimer UV (Ultraviolet) light irradiation, and ITRO using flame. Treatment, wet etching treatment using sodium metal. By this surface treatment, polar functional groups such as hydroxyl groups, carbonyl groups, and carboxyl groups are introduced into the surface of the film 1, and as a result, the adhesion to other surfaces is further improved.

Hereinafter, the laminate of the present invention (hereinafter, also referred to as "the present laminate") will be described. In this lamination system, a laminate of the F polymer layer (the layer composed of the film of the present invention) and the base material layer is sequentially laminated. The layered product is preferably obtained by combining the film of the present invention with a film-like or sheet-like substrate other than the film of the present invention in a roll-to-roll manner, for example, at the melting temperature of the F polymer -400 Lamination is performed at ℃, or hot pressing is performed at the melting temperature of the F polymer ~ 400 ℃ after overlapping.

As a material of the base material layer in this laminated body, a metal or resin can be mentioned. As resin, a thermoplastic resin, a non-thermofusible resin, an uncured product of a curable resin, a cured product of a curable resin, and the like can be mentioned. In particular, metal and heat-resistant resin are preferable. The base material layer in this laminate is preferably a layer formed of a film-like or sheet-like base material. As a film-shaped or sheet-shaped base material, a metal foil and a heat-resistant resin film are preferable. The base material layer in this laminate may also be a resin layer or a metal layer formed on the surface of the film of the present invention by a method such as coating or plating.

When the base material layer in this 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 can be easily adhered more firmly. Therefore, the laminated body which has the film of this invention with high film thickness precision, and the printed circuit board obtained by processing it are easy to express electrical characteristics remarkably. Specifically, when the base material layer in the laminate is formed of a metal foil, the dielectric loss factor of the F polymer layer of the laminate at a frequency of 10 GHz is preferably 0.0001 to 0.0020.

The material of the metal foil may, for example, be iron, copper, nickel, titanium, aluminum, or alloys thereof (stainless steel, nickel 42 alloy, etc.). As a metal foil, a rolled copper foil and an electrolytic copper foil are preferable. The surface of the metal foil can also be subjected to anti-rust treatment (formation of oxide films such as chromate). Moreover, the surface of a metal foil can also be processed with a silane coupling agent. The treatment range at this 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.

Moreover, as a metal foil, the metal foil with a carrier which consists of two or more layers of metal foils can also be used. Examples of the metal foil with carriers include carrier copper foil (thickness: 10 to 35 μm), and ultra-thin copper foil (thickness: 2 to 5 μm) laminated on the carrier copper foil with a dielectric release layer. Copper foil with carrier. If the copper foil with the carrier is used, a fine pattern can be formed by the MSAP (modified semi-additive) process. As said peeling layer, the metal layer containing nickel or chromium, and the multilayer metal layer obtained by laminating|stacking this metal layer are preferable. As a specific example of the metal foil with a carrier, the product called "FUTF-5DAF-2" manufactured by Futian Metal Foil Powder Industry Co., Ltd. can be exemplified.

The base material layer of this laminate may be a metal layer formed by a vapor deposition method and 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 sputtering or electroless plating, and then growing the metal from the seed layer by electroplating. The surface of the film of the present invention may also be surface-treated before the seed layer is formed. As a method of surface treatment, annealing treatment, corona treatment, plasma treatment, ozone treatment, excimer treatment, and silane coupling treatment can be mentioned. As the metal to be plated by the electroless plating method, copper and nickel may, for example, be mentioned. As the metal in the seed layer, copper, nickel, chromium, nickel-chromium alloy, titanium alloy, and the like can be exemplified. As a metal plated by electroplating, copper can be mentioned.

When the base material layer in this laminate is a layer of a heat-resistant resin film, the film contains one or more heat-resistant resins, and may be a single-layer film or a multi-layer film. Glass fibers, carbon fibers, 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 layered product is preferably a layered product in which the structure of the film of the present invention is layered on both surfaces 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 linear expansion coefficient of the laminated body is remarkably lowered, and warpage is less likely to occur. As the heat-resistant resin, polyimide, polyarylate, polyamide, polyarylene, aromatic polyamide, aromatic polyetheramide, polyphenylene sulfide, polyaryletherketone, polyamide may, for example, be mentioned. Imide, liquid crystal polyester, liquid crystal polyester imide, preferably polyimide (especially aromatic polyimide).

The thickness (total thickness) of this laminate as a heat-resistant resin film having the film of the present invention on both surfaces is preferably 220 μm or more, more preferably 250 μm or more. The above-mentioned thickness is preferably 500 μm or less. In this 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. About the said ratio, 5 or less is preferable. In this case, the properties of the heat-resistant resin film (higher yield strength, difficult plastic deformation) and the properties of the F polymer layer (lower water absorption) are balanced.

Specific examples of the laminate include a metal foil laminate having a metal foil and an F polymer layer on at least one surface of the metal foil, and a metal foil laminate having both a polyimide film and the polyimide film. Multilayer film of F polymer layer on the surface. As a preferred form of the laminate in which the base material layer is a heat-resistant resin film, the film of the present invention, the polyimide film, and the film of the present invention are laminated in this order in direct contact with the three-layer film. The flexible resin film is a polyimide film with a thickness of 20-100 μm. In this form, the thickness of the two films of the present invention is the same, preferably 100 to 200 μm. Moreover, it is preferable that it is 0.5-5 about the ratio of the total thickness of two films of this invention with respect to the thickness of a polyimide film. The layered product of this form is most likely to exhibit the effects of the above-described layered product.

Here, the outermost surface (surface on the opposite side to the base material layer of the F polymer layer) of the layered product may be further surface-treated to further improve the linear expansion or adhesiveness. As a method of surface treatment, annealing treatment, corona treatment, plasma treatment, ozone treatment, excimer treatment, and silane coupling treatment can be mentioned. Regarding the conditions in the annealing treatment, the temperature is preferably 120 to 180° C., the pressure is 0.005 to 0.015 MPa, and the time is preferably 30 to 120 minutes. As a gas used for plasma processing, oxygen gas, nitrogen gas, rare gas (argon gas etc.), hydrogen gas, ammonia gas, and vinyl acetate are mentioned. These gases may be used alone or in combination of two or more.

The metal foil of the laminate (metal foil with F polymer layer) in which the base material layer is a metal foil is etched to form a transmission circuit to obtain a printed circuit board. Specifically, a printed circuit board can be produced by etching a metal foil to process it into a specific transmission circuit, or by plating a metal foil (semi-additive method (SAP method), MSAP method, etc.) The foils are processed into specific transmission circuits. The printed circuit board made of the metal foil with the F polymer layer has the transmission circuit formed of the metal foil and the F polymer layer in this order. As a specific example of the structure of a printed circuit board, a transmission circuit/F polymer layer/prepreg layer, a transmission circuit/F polymer layer/prepreg layer/F polymer layer/transmission circuit can be mentioned. When manufacturing the 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 cover layer films may also be formed of the films 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 said embodiment. For example, the film of the present invention and the layered product of the present invention may add other arbitrary structures to the above-mentioned structures, and it is preferable to replace them with any structures that exhibit the same function. In addition, in the production method of the present invention, other arbitrary steps may be added to the configuration of the above-mentioned embodiment, and it is preferable to replace the arbitrary steps with the same functions. [Example]

Hereinafter, the present invention will be described in detail using examples, but the present invention is not limited to these examples. Details of each ingredient are shown below. [F polymer] F polymer 1: a polymer containing 98.0 mol % of TFE units, 0.1 mol % of NAH units and 1.9 mol % of PPVE units and having an acid anhydride group (melting temperature 300°C) F polymer 2: A polymer containing 98.0 mol % of TFE units and 2.0 mol % of PPVE units and having no functional group (melting temperature 300°C) Furthermore, in the F polymer 1, the number of carbon atoms in the main chain is 1×10 ⁶ , with 1000 carbonyl-containing groups, and F polymer 2 has 40. [Particles] Particle 1: Particles of F polymer 1 (diameter: 2.2 mm) [Measurement of haze] The haze (turbidity) of the films obtained in each of the examples and the like was based on JIS K 7136, using NDH5000 (Japan manufactured by Denshoku Industries Co., Ltd.) to measure. [Thermal expansion and contraction rate] According to JISK7133:1999, after the film is cut into a size of 120 mm × 120 mm, a 100 mm line is drawn along the film traveling direction (MD) and width direction (TD), and the length of the line is measured. . The film was left to stand in an oven at 180°C and heated for 30 minutes, then cooled to 25°C naturally, and then the length of the marking line was measured again, and the stretch ratio was calculated according to the following formula. Formula: {(Length of marking line before heating)-(Length of marking line after heating)}/(Length of marking line before heating)×100 [Film appearance] Put the film on the surface of the smooth glass and confirm The presence or absence of warpage (waving) was evaluated according to the following criteria. ○: Warpage (waving) was not recognized. ×: Warpage (waving) was confirmed.

[example 1] (1) Manufacture of film After the F polymer 1 was put into an extruder at 350° C., it was extruded from a T die having a width of 1600 mm so that the thickness might be 125 μm. The die temperature was 350°C and the die lip temperature was 370°C. The extruded F polymer 1 in the molten state was sandwiched by the first cooling roll 30 at 200 °C by the quenching roll 301 as a metal elastic roll controlled at 90 °C. The air knife (height: 50 mm) installed in the direction of the tangent line where the rolls meet is directed toward the first cooling roll, and blows a slit of 200°C uniformly in a line along the width direction of the first cooling roll 30 at a wind speed of 15 m/s The F polymer is pressed against the first cooling roll 30 by the air flow, and after passing through the second cooling roll 40 at 90°C, it is pulled and wound by the take-up 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 and contraction ratio after heating at 180° C. for 30 minutes was 0.2% in MD and −0.3% in TD. In addition, a hopper was connected to the front stage of the kneading section of the extruder, and the feeding of the F polymer 1 was adjusted as follows. Pa or less, and heat treatment was performed so that the temperature of the F polymer in the connecting portion reached 180°C. In addition, the F polymer 1 in the molten state extruded from the T-die was heated to 320° C. with a non-contact heater before it came into contact with the quench roll and the first roll. (2) Manufacture and evaluation of antenna substrate On the PFA film 1, a nickel-chromium alloy layer is formed by sputtering a nickel-chromium alloy with a thickness of 10 nm by a roll-to-roll method, and then, on the nickel-chromium alloy layer, sputtering is performed with a thickness of 200 nm. copper to form a copper layer. Furthermore, on the copper layer, after laminating a dry film resist with a 90 degreeC roll, it exposed and developed so that a width might become 6 micrometers. By electroplating copper using copper sulfate, the mesh portion was plated until its thickness became 6 μm. Then, the dry film resist was peeled off, and then, the copper layer and the nichrome layer formed by sputtering were removed by etching to obtain an antenna substrate. The resistance of the obtained antenna substrate was measured to evaluate whether or not it was conductive. If it was conductive, it was evaluated as (○), and if it was not conductive, it was evaluated as (x). In addition, the haze after the mesh antenna was formed on the antenna substrate was measured by the above-mentioned method. Table 1 shows the film production conditions, film properties, and performance evaluation results as an antenna.

[Example 2] A film (PFA) was produced in the same manner as in (1) of Example 1, except that the F polymer 2 was used instead of the F polymer 1, and the first cooling roll was not blown with the air knife to the molten F polymer 2. film 2). Using the obtained PFA film 2, an antenna substrate and an antenna were produced in the same manner as in (2) of Example 1, and evaluated in the same manner. Table 1 shows the film production conditions, film properties, and performance evaluation results as an antenna.

[Example 3] The F polymer 1 was extruded from the T-die so as to have a thickness of 125 μm, without using the quench roll 301 (that is, without being sandwiched between the quench roll 301 and the first cooling roll 30 ), and cooled in the first A film (PFA film 3) was produced in the same manner as in (1) of Example 1, except that the film was wound up through the first cooling roll without blowing air to the molten F polymer 1 with an air knife. Using the obtained PFA film 3, an antenna substrate and an antenna were produced in the same manner as in (2) of Example 1, and evaluated in the same manner. Table 1 shows the film production conditions and film properties of the obtained PFA film 3, and the results of performance evaluation as an antenna. The adhesion of the PFA film 3 to the first cooling roll was poor, and "air marks", ie, traces left by air entering between the film and the first cooling roll, were seen, and the appearance was poor.

[Table 1] Table 1 example 1 Example 2 Example 3 Film making conditions (unit) Types of PFA PFA1 PFA2 PFA1 Film thickness (μm) 125 125 125 heater temperature (°C) 320 320 320 1st cooling roll temperature (°C) 200 200 200 Chill Roll *Temperature (°C) 90 90 - air knife have none none Membrane evaluation haze (%) 2 4 12 Thermal expansion ratio (MD/TD) (%/%) 0.2/-0.3 0.2/-0.3 0.8/-1.5 Exterior ○ ○ × Antenna Evaluation turn on ○ ○ × haze (%) 4 6 15 ﹡Use metal elastic roller [Industrial Availability]

Since the film of the present invention is transparent and has excellent dimensional stability, it can be used 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 obtained processed article can be applied to a flexible printed circuit board with transparency, antenna parts, printed circuit boards, sports equipment, and food industries. Various fields such as soft devices such as supplies, wearable devices and medical devices that focus on design. Furthermore, the entire contents of Japanese Patent Application No. 2020-062167, the scope of application, abstract, and drawings filed on March 31, 2020 are incorporated herein by reference as a disclosure of the specification of the present invention.

1: Membrane 2: Hopper 3: Mixing Department 5:T mode 6: Static mixer 10,101: Manufacturing devices 11: Extrusion forming device 20: T mold 21: Die lip 21: Part 1 22: Part 2 30: 1st cooling roll 31: Cylinder 32: Screw 33: Gearbox 34: Motor 35: Heater 40: 2nd cooling roll 50: take-up roll 61, 62: Conveying rollers 70: Air Knife 80: heater 211: Heater 212: Connector 221: Heater 222: Connector 301: quench roll 311: Front opening part 331: Rotary axis 341: Rotary axis D: diameter L: full length P1: Pump P2: Pump S: Peripheral speed t: thickness

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

1: Membrane

10: Manufacturing device

20: T mold

21: Die lip

30: 1st cooling roll

40: 2nd cooling roll

50: take-up roll

61, 62: Conveying rollers

70: Air Knife

301: quench roll

S: Peripheral speed

t: thickness

Claims (15)

A film, which is an extruded film composed of a tetrafluoroethylene-based polymer, the thickness of which is 100-200 μm, the haze is 8% or less, and the thermal expansion and contraction rate after heating at 180 ° C for 30 minutes in the traveling direction of the film And the width direction is -1 to +1%. The film of claim 1, wherein the tetrafluoroethylene-based polymer comprises a tetrafluoroethylene-based unit and a perfluoro(alkyl vinyl ether)-based unit. The film according to claim 1 or 2, wherein the tetrafluoroethylene-based polymer contains a perfluoro(alkyl vinyl ether)-based unit and has a polar functional group, or contains 2.0 to 5.0 mol % based on the total unit. Units of perfluoro(alkyl vinyl ether) and no polar functional groups. The film according to any one of claims 1 to 3, wherein 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, which is a method for producing the film according to any one of claims 1 to 4 by T-die casting, comprising the following operations: The vinyl fluoride-based polymer was extruded from a die in a molten state, and the obtained film was sandwiched between two temperature-controlled rolls and cooled. The manufacturing method of claim 5, wherein the temperature of one of the two temperature-controlled rolls is 150 to 250°C, and the temperature of the other is 80 to 150°C. The production method according to claim 5 or 6, comprising an extrusion molding apparatus having a kneading section and a hopper connected to the kneading section, and feeding into the hopper a tetrafluoroethylene-based polymer having a melting temperature of 260 to 320°C When the pellets are melted and kneaded by the kneading section and the melt-kneaded product is ejected from the T-die to manufacture a film, the following operation is further included: the temperature of the pellets in the connection part of the hopper and the kneading section is adjusted to (the above-mentioned Melting temperature -200) - (the said melting temperature-100) °C range, and then the said pellet is supplied to the said kneading part. The manufacturing method according to any one of claims 5 to 7, wherein the diameter of the above-mentioned particles is 1.0-4.0 mm. The manufacturing method according to any one of claims 5 to 8, wherein the hopper includes a first-stage portion and a multi-stage hopper arranged in a second-stage portion closer to the kneading portion than the first-stage portion. The production 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. The manufacturing method according to any one of claims 5 to 10, wherein the extrusion molding device includes: a T die connected to the side opposite to the hopper in the axial direction of the kneading portion; and a static mixer provided in Between the above-mentioned kneading part and the above-mentioned T-die. The production method according to any one of claims 5 to 11, further comprising the operation of discharging the tetrafluoroethylene-based polymer in a molten state from a T-die, and contacting the tetrafluoroethylene-based polymer in a molten state with the tetrafluoroethylene-based polymer in a molten state. The first cooling roll is heated by a non-contact heating section. The production method of claim 12, wherein the difference between the temperature of the tetrafluoroethylene-based polymer in the T-die and the temperature of the first cooling roll 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-based polymer in the T-die and the temperature of the non-contact heating section is 70°C or less. A layered product having a layer composed of the film according to any one of claims 1 to 4, and a base material layer composed of a base material other than the film.

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